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2011 National Monitoring Programs Annual
Report (UATMP, NATTS, CSATAM)
Volume 1: Main
August 2013
Final Report
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EPA-454/R-13-007a
August 2013
2011 National Monitoring Programs Annual Report (UATMP, NATTS, CSATAM)
Volume 1: Main
By:
Eastern Research Group, Inc.
Morrisville, NC 27560
Prepared for:
Margaret Dougherty and David Shelow
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Contract No. EP-D-09-048
Delivery Orders 11, 15, 20, 21, 22, 23, 24, & 25
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Research Triangle Park, NC 27711
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2011 National Monitoring Programs
Annual Report
(UATMP, NATTS, CSATAM)
Final Report
EPA Contract No. EP-D-09-048
Delivery Orders 11,15, 20, 21, 22, 23, 24, & 25
Prepared for:
Margaret Dougherty and David Shelow
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Prepared by:
Eastern Research Group, Inc.
601 Keystone Park Drive, Suite 700
Morrisville, NC 27560
August 2013
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DISCLAIMER
Through its Office of Air Quality Planning and Standards, the U.S. Environmental Protection
Agency funded and managed the research described in this report under EPA Contract
No. EP-D-09-048 to Eastern Research Group, Inc. This report has been subjected to the
Agency's peer and administrative review and has been approved for publication as an EPA
document. Mention of trade names or commercial products in this report does not constitute
endorsement or recommendation for their use.
11
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TABLE OF CONTENTS
Page
List of Appendices xix
List of Figures xx
List of Tables xxxiv
List of Acronyms xliii
Abstract xlv
1.0 Introduction 1-1
1.1 Background 1-1
1.2 The Report 1-2
2.0 The 2011 National Monitoring Programs Network 2-1
2.1 Monitoring Locations 2-1
2.2 Analytical Methods and Pollutants Targeted for Monitoring 2-12
2.2.1 VOC and SNMOC Concurrent Sampling and Analytical Methods ... 2-14
2.2.2 Carbonyl Compound Sampling and Analytical Method 2-18
2.2.3 PAH Sampling and Analytical Method 2-19
2.2.4 Metals Sampling and Analytical Method 2-20
2.2.5 Hexavalent Chromium Sampling and Analytical Method 2-21
2.3 Sample Collection Schedules 2-22
2.4 Completeness 2-28
3.0 Summary of the 2011 National Monitoring Programs Data Treatment and
Methods 3-1
3.1 Approach to Data Treatment 3-1
3.2 Human Health Risk and the Pollutants of Interest 3-3
3.3 Noncancer Risk-Based Screening Evaluation Using Minimum Risk Levels 3-7
3.4 Additional Program-Level Analyses of the 2011 National Monitoring
Programs Dataset 3-8
3.4.1 The Effect of Mobile Source Emissions on Spatial Variations 3-8
3.4.2 Variability Analyses 3-9
3.4.3 Greenhouse Gas Assessment 3-11
in
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TABLE OF CONTENTS (Continued)
Page
3.5 Additional Site-Specific Analyses 3-11
3.5.1 Site Characterization 3-11
3.5.2 Meteorological Analysis 3-12
3.5.2.1 Back Trajectory Analysis 3-13
3.5.2.2 Wind Rose Analysis 3-14
3.5.3 Site-Specific Comparison to Program-level Average
Concentrations 3-15
3.5.4 Site Trends Analysis 3-16
3.5.5 Preliminary Risk-Based Screening and Pollutants of Interest 3-17
3.5.5.1 Emission Tracer Analysis 3-18
3.5.5.2 Cancer Risk and Noncancer Hazard Approximations 3-18
3.5.5.3 Risk-Based Emissions Assessment 3-19
4.0 Summary of the 2011 National Monitoring Programs Data 4-1
4.1 Statistical Results 4-1
4.1.1 Target Pollutant Detection Rates 4-1
4.1.2 Concentration Range and Data Distribution 4-13
4.1.3 Central Tendency 4-13
4.2 Preliminary Risk-Based Screening and Pollutants of Interest 4-15
4.2.1 Concentrations of the Pollutants of Interest 4-21
4.2.2 Risk-Based Screening Assessment Using MRLs 4-30
4.3 The Impact of Mobile Sources 4-33
4.3.1 Mobile Source Emissions 4-33
4.3.2 Hydrocarbon Concentrations 4-36
4.3.3 Motor Vehicle Ownership 4-36
4.3.4 Estimated Traffic Volume 4-38
4.3.5 Vehicle Miles Traveled 4-39
4.4 Variability Analysis 4-39
4.4.1 Coefficient of Variation and Inter-site Variability 4-39
4.4.2 Quarterly Variability Analysis 4-70
4.5 Greenhouse Gases 4-104
5.0 Sites in Arizona 5-1
5.1 Site Characterization 5-1
5.2 Meteorological Characterization 5-7
5.2.1 Climate Summary 5-7
5.2.2 Meteorological Conditions in 2011 5-8
iv
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TABLE OF CONTENTS (Continued)
Page
5.2.3 Back Trajectory Analysis 5-10
5.2.4 Wind Rose Comparison 5-13
5.3 Pollutants of Interest 5-16
5.4 Concentrations 5-19
5.4.1 2011 Concentration Averages 5-19
5.4.2 Concentration Comparison 5-23
5.4.3 Concentration Trends 5-28
5.5 Additional Risk-Based Screening Evaluations 5-32
5.5.1 Risk-Based Screening Assessment Using MRLs 5-32
5.5.2 Cancer Risk and Noncancer Hazard Approximations 5-33
5.5.3 Risk-Based Emissions Assessment 5-36
5.6 Summary of the 2011 Monitoring Data for PXSS and SPAZ 5-40
6.0 Sites in California 6-1
6.1 Site Characterization 6-1
6.2 Meteorological Characterization 6-11
6.2.1 Climate Summary 6-11
6.2.2 Meteorological Conditions in 2011 6-12
6.2.3 Back Trajectory Analysis 6-14
6.2.4 Wind Rose Comparison 6-19
6.3 Pollutants of Interest 6-24
6.4 Concentrations 6-26
6.4.1 2011 Concentration Averages 6-26
6.4.2 Concentration Comparison 6-28
6.4.3 Concentration Trends 6-31
6.5 Additional Risk-Based Screening Evaluations 6-32
6.5.1 Risk-Based Screening Assessment Using MRLs 6-32
6.5.2 Cancer Risk and Noncancer Hazard Approximations 6-32
6.5.3 Risk-Based Emissions Assessment 6-34
6.6 Summary of the 2011 Monitoring Data for CELA, RUCA, and SJJCA 6-40
7.0 Sites in Colorado 7-1
7.1 Site Characterization 7-1
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TABLE OF CONTENTS (Continued)
Page
7.2 Meteorological Characterization 7-12
7.2.1 Climate Summary 7-12
7.2.2 Meteorological Conditions in 2011 7-13
7.2.3 Back Trajectory Analysis 7-16
7.2.4 Wind Rose Comparison 7-22
7.3 Pollutants of Interest 7-29
7.4 Concentrations 7-31
7.4.1 2011 Concentration Averages 7-32
7.4.2 Concentration Comparison 7-37
7.4.3 Concentration Trends 7-42
7.5 Additional Risk-Based Screening Evaluations 7-47
7.5.1 Risk-Based Screening Assessment Using MRLs 7-47
7.5.2 Cancer Risk and Noncancer Hazard Approximations 7-48
7.5.3 Risk-Based Emissions Assessment 7-51
7.6 Summary of the 2011 Monitoring Data for the Colorado Monitoring Sites 7-59
8.0 Site in the District of Columbia 8-1
8.1 Site Characterization 8-1
8.2 Meteorological Characterization 8-6
8.2.1 Climate Summary 8-6
8.2.2 Meteorological Conditions in 2011 8-6
8.2.3 Back Trajectory Analysis 8-8
8.2.4 Wind Rose Comparison 8-10
8.3 Pollutants of Interest 8-12
8.4 Concentrations 8-13
8.4.1 2011 Concentration Averages 8-13
8.4.2 Concentration Comparison 8-15
8.4.3 Concentration Trends 8-17
8.5 Additional Risk-Based Screening Evaluations 8-18
8.5.1 Risk-Based Screening Assessment Using MRLs 8-18
8.5.2 Cancer Risk and Noncancer Hazard Approximations 8-19
8.5.3 Risk-Based Emissions Assessment 8-20
8.6 Summary of the 2011 Monitoring Data for WADC 8-24
VI
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TABLE OF CONTENTS (Continued)
Page
9.0 Sites in Florida 9-1
9.1 Site Characterization 9-1
9.2 Meteorological Characterization 9-13
9.2.1 Climate Summary 9-13
9.2.2 Meteorological Conditions in 2011 9-13
9.2.3 Back Trajectory Analysis 9-16
9.2.4 Wind Rose Comparison 9-23
9.3 Pollutants of Interest 9-31
9.4 Concentrations 9-33
9.4.1 2011 Concentration Averages 9-33
9.4.2 Concentration Comparison 9-36
9.4.3 Concentration Trends 9-42
9.5 Additional Risk-Based Screening Evaluations 9-51
9.5.1 Risk-Based Screening Assessment Using MRLs 9-51
9.5.2 Cancer Risk and Noncancer Hazard Approximations 9-51
9.5.3 Risk-Based Emissions Assessment 9-54
9.6 Summary of the 2011 Monitoring Data for the Florida Monitoring Sites 9-62
10.0 Site in Georgia 10-1
10.1 Site Characterization 10-1
10.2 Meteorological Characterization 10-6
10.2.1 Climate Summary 10-6
10.2.2 Meteorological Conditions in 2011 10-7
10.2.3 Back Trajectory Analysis 10-7
10.2.4 Wind Rose Comparison 10-10
10.3 Pollutants of Interest 10-12
10.4 Concentrations 10-13
10.4.1 2011 Concentration Averages 10-13
10.4.2 Concentration Comparison 10-15
10.4.3 Concentration Trends 10-17
10.5 Additional Risk-Based Screening Evaluations 10-18
10.5.1 Risk-Based Screening Assessment Using MRLs 10-18
10.5.2 Cancer Risk and Noncancer Hazard Approximations 10-19
10.5.3 Risk-Based Emissions Assessment 10-20
vii
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TABLE OF CONTENTS (Continued)
Page
10.6 Summary of the 2011 Monitoring Data for SDGA 10-24
11.0 Sites in Illinois 11-1
11.1 Site Characterization 11-1
11.2 Meteorological Characterization 11-7
11.2.1 Climate Summary 11-8
11.2.2 Meteorological Conditions in 2011 11-8
11.2.3 Back Trajectory Analysis 11-10
11.2.4 Wind Rose Comparison 11-13
11.3 Pollutants of Interest 11-16
11.4 Concentrations 11-19
11.4.1 2011 Concentration Averages 11-19
11.4.2 Concentration Comparison 11-25
11.4.3 Concentration Trends 11-31
11.5 Additional Risk-Based Screening Evaluations 11-43
11.5.1 Risk-Based Screening Assessment Using MRLs 11-43
11.5.2 Cancer Risk and Noncancer Hazard Approximations 11-43
11.5.3 Risk-Based Emissions Assessment 11-46
11.6 Summary of the 2011 Monitoring Data for NBIL and SPIL 11-50
12.0 Sites in Indiana 12-1
12.1 Site Characterization 12-1
12.2 Meteorological Characterization 12-8
12.2.1 Climate Summary 12-8
12.2.2 Meteorological Conditions in 2011 12-9
12.2.3 Back Trajectory Analysis 12-11
12.2.4 Wind Rose Comparison 12-14
12.3 Pollutants of Interest 12-18
12.4 Concentrations 12-19
12.4.1 2011 Concentration Averages 12-19
12.4.2 Concentration Comparison 12-21
12.4.3 Concentration Trends 12-22
12.5 Additional Risk-Based Screening Evaluations 12-25
12.5.1 Risk-Based Screening Assessment Using MRLs 12-25
viii
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TABLE OF CONTENTS (Continued)
Page
12.5.2 Cancer Risk and Noncancer Hazard Approximations 12-26
12.5.3 Risk-Based Emissions Assessment 12-27
12.6 Summary of the 2011 Monitoring Data for INDEM and WPIN 12-31
13.0 Site in Kentucky 13-1
13.1 Site Characterization 13-1
13.2 Meteorological Characterization 13-6
13.2.1 Climate Summary 13-6
13.2.2 Meteorological Conditions in 2011 13-6
13.2.3 Back Trajectory Analysis 13-8
13.2.4 Wind Rose Comparison 13-10
13.3 Pollutants of Interest 13-12
13.4 Concentrations 13-13
13.4.1 2011 Concentration Averages 13-13
13.4.2 Concentration Comparison 13-16
13.4.3 Concentration Trends 13-19
13.5 Additional Risk-Based Screening Evaluations 13-19
13.5.1 Risk-Based Screening Assessment Using MRLs 13-20
13.5.2 Cancer Risk and Noncancer Hazard Approximations 13-20
13.5.3 Risk-Based Emissions Assessment 13-22
13.6 Summary of the 2011 Monitoring Data for GLKY 13-26
14.0 Site in Massachusetts 14-1
14.1 Site Characterization 14-1
14.2 Meteorological Characterization 14-6
14.2.1 Climate Summary 14-6
14.2.2 Meteorological Conditions in 2011 14-7
14.2.3 Back Trajectory Analysis 14-7
14.2.4 Wind Rose Comparison 14-10
14.3 Pollutants of Interest 14-13
14.4 Concentrations 14-14
14.4.1 2011 Concentration Averages 14-14
14.4.2 Concentration Comparison 14-16
14.4.3 Concentration Trends 14-20
ix
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TABLE OF CONTENTS (Continued)
Page
14.5 Additional Risk-Based Screening Evaluations 14-24
14.5.1 Risk-Based Screening Assessment Using MRLs 14-24
14.5.2 Cancer Risk and Noncancer Hazard Approximations 14-24
14.5.3 Risk-Based Emissions Assessment 14-26
14.6 Summary of the 2011 Monitoring Data for BOMA 14-30
15.0 Sites in Michigan 15-1
15.1 Site Characterization 15-1
15.2 Meteorological Characterization 15-9
15.2.1 Climate Summary 15-9
15.2.2 Meteorological Conditions in 2011 15-9
15.2.3 Back Trajectory Analysis 15-11
15.2.4 Wind Rose Comparison 15-15
15.3 Pollutants of Interest 15-19
15.4 Concentrations 15-21
15.4.1 2011 Concentration Averages 15-22
15.4.2 Concentration Comparison 15-26
15.4.3 Concentration Trends 15-30
15.5 Additional Risk-Based Screening Evaluations 15-36
15.5.1 Risk-Based Screening Assessment Using MRLs 15-36
15.5.2 Cancer Risk and Noncancer Hazard Approximations 15-36
15.5.3 Risk-Based Emissions Assessment 15-38
15.6 Summary of the 2011 Monitoring Data for DEMI, RRMI, and SWMI 15-44
16.0 Site in Missouri 16-1
16.1 Site Characterization 16-1
16.2 Meteorological Characterization 16-6
16.2.1 Climate Summary 16-6
16.2.2 Meteorological Conditions in 2011 16-6
16.2.3 Back Trajectory Analysis 16-8
16.2.4 Wind Rose Comparison 16-10
16.3 Pollutants of Interest 16-13
16.4 Concentrations 16-14
16.4.1 2011 Concentration Averages 16-15
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TABLE OF CONTENTS (Continued)
Page
16.4.2 Concentration Comparison 16-19
16.4.3 Concentration Trends 16-24
16.5 Additional Risk-Based Screening Evaluations 16-32
16.5.1 Risk-Based Screening Assessment Using MRLs 16-32
16.5.2 Cancer Risk and Noncancer Hazard Approximations 16-33
16.5.3 Risk-Based Emissions Assessment 16-35
16.6 Summary of the 2011 Monitoring Data for S4MO 16-39
17.0 Sites in New Jersey 17-1
17.1 Site Characterization 17-1
17.2 Meteorological Characterization 17-13
17.2.1 Climate Summary 17-13
17.2.2 Meteorological Conditions in 2011 17-13
17.2.3 Back Trajectory Analysis 17-15
17.2.4 Wind Rose Comparison 17-20
17.3 Pollutants of Interest 17-26
17.4 Concentrations 17-30
17.4.1 2011 Concentration Averages 17-30
17.4.2 Concentration Comparison 17-36
17.4.3 Concentration Trends 17-39
17.5 Additional Risk-Based Screening Evaluations 17-51
17.5.1 Risk-Based Screening Assessment Using MRLs 17-52
17.5.2 Cancer Risk and Noncancer Hazard Approximations 17-52
17.5.3 Risk-Based Emissions Assessment 17-56
17.6 Summary of the 2011 Monitoring Data for the New Jersey Monitoring
Sites 17-62
18.0 Sites in New York 18-1
18.1 Site Characterization 18-1
18.2 Meteorological Characterization 18-9
18.2.1 Climate Summary 18-9
18.2.2 Meteorological Conditions in 2011 18-9
18.2.3 Back Trajectory Analysis 18-11
18.2.4 Wind Rose Comparison 18-15
XI
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TABLE OF CONTENTS (Continued)
Page
18.3 Pollutants of Interest 18-18
18.4 Concentrations 18-20
18.4.1 2011 Concentration Averages 18-20
18.4.2 Concentration Comparison 18-22
18.4.3 Concentration Trends 18-25
18.5 Additional Risk-Based Screening Evaluations 18-25
18.5.1 Risk-Based Screening Assessment Using MRLs 18-25
18.5.2 Cancer Risk and Noncancer Hazard Approximations 18-26
18.5.3 Risk-Based Emissions Assessment 18-27
18.6 Summary of the 2011 Monitoring Data for MONY and ROCH 18-31
19.0 Sites in Oklahoma 19-1
19.1 Site Characterization 19-1
19.2 Meteorological Characterization 19-14
19.2.1 Climate Summary 19-14
19.2.2 Meteorological Conditions in 2011 19-14
19.2.3 Back Trajectory Analysis 19-15
19.2.4 Wind Rose Comparison 19-23
19.3 Pollutants of Interest 19-30
19.4 Concentrations 19-35
19.4.1 2011 Concentration Averages 19-35
19.4.2 Concentration Comparison 19-45
19.4.3 Concentration Trends 19-54
19.5 Additional Risk-Based Screening Evaluations 19-61
19.5.1 Risk-Based Screening Assessment Using MRLs 19-61
19.5.2 Cancer Risk and Noncancer Hazard Approximations 19-61
19.5.3 Risk-Based Emissions Assessment 19-67
19.6 Summary of the 2011 Monitoring Data for the Oklahoma Monitoring Sites.. 19-75
20.0 Site in Rhode Island 20-1
20.1 Site Characterization 20-1
20.2 Meteorological Characterization 20-6
20.2.1 Climate Summary 20-6
20.2.2 Meteorological Conditions in 2011 20-7
xii
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TABLE OF CONTENTS (Continued)
Page
20.2.3 Back Trajectory Analysis 20-7
20.2.4 Wind Rose Comparison 20-10
20.3 Pollutants of Interest 20-13
20.4 Concentrations 20-14
20.4.1 2011 Concentration Averages 20-14
20.4.2 Concentration Comparison 20-16
20.4.3 Concentration Trends 20-18
20.5 Additional Risk-Based Screening Evaluations 20-19
20.5.1 Risk-Based Screening Assessment Using MRLs 20-19
20.5.2 Cancer Risk and Noncancer Hazard Approximations 20-19
20.5.3 Risk-Based Emissions Assessment 20-21
20.6 Summary of the 2011 Monitoring Data for PRRI 20-25
21.0 Site in South Carolina 21-1
21.1 Site Characterization 21-1
21.2 Meteorological Characterization 21-6
21.2.1 Climate Summary 21-6
21.2.2 Meteorological Conditions in 2011 21-6
21.2.3 Back Trajectory Analysis 21-8
21.2.4 Wind Rose Comparison 21-10
21.3 Pollutants of Interest 21-12
21.4 Concentrations 21-13
21.4.1 2011 Concentration Averages 21-13
21.4.2 Concentration Comparison 21-15
21.4.3 Concentration Trends 21-17
21.5 Additional Risk-Based Screening Evaluations 21-18
21.5.1 Risk-Based Screening Assessment Using MRLs 21-18
21.5.2 Cancer Risk and Noncancer Hazard Approximations 21-18
21.5.3 Risk-Based Emissions Assessment 21-19
21.6 Summary of the 2011 Monitoring Data for CHSC 21-23
22.0 Sites in South Dakota 22-1
22.1 Site Characterization 22-1
Xlll
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TABLE OF CONTENTS (Continued)
Page
22.2 Meteorological Characterization 22-9
22.2.1 Climate Summary 22-9
22.2.2 Meteorological Conditions in 2011 22-9
22.2.3 Back Trajectory Analysis 22-11
22.2.4 Wind Rose Comparison 22-14
22.3 Pollutants of Interest 22-18
22.4 Concentrations 22-20
22.4.1 2011 Concentration Averages 22-20
22.4.2 Concentration Comparison 22-23
22.4.3 Concentration Trends 22-26
22.5 Additional Risk-Based Screening Evaluations 22-26
22.5.1 Risk-Based Screening Assessment Using MRLs 22-27
22.5.2 Cancer Risk and Noncancer Hazard Approximations 22-27
22.5.3 Risk-Based Emissions Assessment 22-29
22.6 Summary of the 2011 Monitoring Data for SSSD and UCSD 22-33
23.0 Sites in Texas 23-1
23.1 Site Characterization 23-1
23.2 Meteorological Characterization 23-9
23.2.1 Climate Summary 23-9
23.2.2 Meteorological Conditions in 2011 23-9
23.2.3 Back Trajectory Analysis 23-11
23.2.4 Wind Rose Comparison 23-14
23.3 Pollutants of Interest 23-17
23.4 Concentrations 23-19
23.4.1 2011 Concentration Averages 23-19
23.4.2 Concentration Comparison 23-21
23.4.3 Concentration Trends 23-23
23.5 Additional Risk-Based Screening Evaluations 23-24
23.5.1 Risk-Based Screening Assessment Using MRLs 23-24
23.5.2 Cancer Risk and Noncancer Hazard Approximations 23-24
23.5.3 Risk-Based Emissions Assessment 23-25
23.6 Summary of the 2011 Monitoring Data for CAMS 35 and CAMS 85 23-29
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TABLE OF CONTENTS (Continued)
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24.0 Site in Utah 24-1
24.1 Site Characterization 24-1
24.2 Meteorological Characterization 24-6
24.2.1 Climate Summary 24-6
24.2.2 Meteorological Conditions in 2011 24-7
24.2.3 Back Trajectory Analysis 24-7
24.2.4 Wind Rose Comparison 24-10
24.3 Pollutants of Interest 24-11
24.4 Concentrations 24-14
24.4.1 2011 Concentration Averages 24-14
24.4.2 Concentration Comparison 24-18
24.4.3 Concentration Trends 24-23
24.5 Additional Risk-Based Screening Evaluations 24-31
24.5.1 Risk-Based Screening Assessment Using MRLs 24-31
24.5.2 Cancer Risk and Noncancer Hazard Approximations 24-32
24.5.3 Risk-Based Emissions Assessment 24-34
24.6 Summary of the 2011 Monitoring Data for BTUT 24-38
25.0 Sites in Vermont 25-1
25.1 Site Characterization 25-1
25.2 Meteorological Characterization 25-10
25.2.1 Climate Summary 25-10
25.2.2 Meteorological Conditions in 2011 25-11
25.2.3 Back Trajectory Analysis 25-11
25.2.4 Wind Rose Comparison 25-17
25.3 Pollutants of Interest 25-21
25.4 Concentrations 25-24
25.4.1 2011 Concentration Averages 25-24
25.4.2 Concentration Comparison 25-29
25.4.3 Concentration Trends 25-34
25.5 Additional Risk-Based Screening Evaluations 25-35
25.5.1 Risk-Based Screening Assessment Using MRLs 25-35
25.5.2 Cancer Risk and Noncancer Hazard Approximations 25-36
25.5.3 Risk-Based Emissions Assessment 25-39
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TABLE OF CONTENTS (Continued)
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25.6 Summary of the 2011 Monitoring Data for the Vermont Monitoring Sites .... 25-45
26.0 Site in Virginia 26-1
26.1 Site Characterization 26-1
26.2 Meteorological Characterization 26-6
26.2.1 Climate Summary 26-6
26.2.2 Meteorological Conditions in 2011 26-6
26.2.3 Back Trajectory Analysis 26-8
26.2.4 Wind Rose Comparison 26-10
26.3 Pollutants of Interest 26-12
26.4 Concentrations 26-13
26.4.1 2011 Concentration Averages 26-13
26.4.2 Concentration Comparison 26-15
26.43 Concentration Trends 26-16
26.5 Additional Risk-Based Screening Evaluations 26-17
26.5.1 Risk-Based Screening Assessment Using MRLs 26-17
26.5.2 Cancer Risk and Noncancer Hazard Approximations 26-17
26.5.3 Risk-Based Emissions Assessment 26-18
26.6 Summary of the 2011 Monitoring Data for RIVA 26-22
27.0 Site in Washington 27-1
27.1 Site Characterization 27-1
27.2 Meteorological Characterization 27-6
27.2.1 Climate Summary 27-6
27.2.2 Meteorological Conditions in 2011 27-7
27.2.3 Back Trajectory Analysis 27-7
27.2.4 Wind Rose Comparison 27-10
27.3 Pollutants of Interest 27-12
27.4 Concentrations 27-14
27.4.1 2011 Concentration Averages 27-14
27.4.2 Concentration Comparison 27-18
27.4.3 Concentration Trends 27-23
27.5 Additional Risk-Based Screening Evaluations 27-31
27.5.1 Risk-Based Screening Assessment Using MRLs 27-31
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TABLE OF CONTENTS (Continued)
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27.5.2 Cancer Risk and Noncancer Hazard Approximations 27-31
27.5.3 Risk-Based Emissions Assessment 27-33
27.6 Summary of the 2011 Monitoring Data for SEWA 27-37
28.0 Site in Wisconsin 28-1
28.1 Site Characterization 28-1
28.2 Meteorological Characterization 28-6
28.2.1 Climate Summary 28-6
28.2.2 Meteorological Conditions in 2011 28-7
28.2.3 Back Trajectory Analysis 28-7
28.2.4 Wind Rose Comparison 28-10
28.3 Pollutants of Interest 28-12
28.4 Concentrations 28-13
28.4.1 2011 Concentration Averages 28-13
28.4.2 Concentration Comparison 28-14
28.4.3 Concentration Trends 28-15
28.5 Additional Risk-Based Screening Evaluations 28-15
28.5.1 Risk-Based Screening Assessment Using MRLs 28-15
28.5.2 Cancer Risk and Noncancer Hazard Approximations 28-16
28.5.3 Risk-Based Emissions Assessment 28-17
28.6 Summary of the 2011 Monitoring Data for HOWI 28-20
29.0 Data Quality 29-1
29.1 Completeness 29-1
29.2 Method Precision 29-2
29.2.1 VOC Method Precision 29-4
29.2.2 SNMOC Method Precision 29-12
29.2.3 Carbonyl Compound Method Precision 29-17
29.2.4 PAH Method Precision 29-19
29.2.5 Metals Method Precision 29-20
29.2.6 Hexavalent Chromium Method Precision 29-21
29.3 Analytical Precision 29-23
29.3.1 VOC Analytical Precision 29-24
29.3.2 SNMOC Analytical Precision 29-32
29.3.3 Carbonyl Compound Analytical Precision 29-37
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TABLE OF CONTENTS (Continued)
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29.3.4 PAH Analytical Precision 29-39
29.3.5 Metals Analytical Precision 29-40
29.3.6 Hexavalent Chromium Analytical Precision 29-41
29.4 Accuracy 29-42
30.0 Results, Conclusions, and Recommendations 30-1
30.1 Summary of Results 30-1
30.1.1 National-level Results Summary 30-1
30.1.2 State-level Results Summary 30-2
30.1.3 Composite Site-level Results Summary 30-19
30.1.4 Data Quality Results Summary 30-21
30.2 Conclusions 30-21
30.3 Recommendations 30-23
31.0 References 31-1
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TABLE OF CONTENTS (Continued)
List of Appendices
Appendix A AQS Site Descriptions for the 2011 NATTS, UATMP, and CSATAM
Monitoring Sites
Appendix B Range of Method Detection Limits (MDLs)
Appendix C 2011 VOC Raw Data
Appendix D 2011 SNMOC Raw Data
Appendix E 2011 Carbonyl Compounds Raw Data
Appendix F 2011 PAH Raw Data
Appendix G 2011 Metals Raw Data
Appendix H 2011 Hexavalent Chromium Raw Data
Appendix I Summary of Invalidated 2011 Samples
Appendix J 2011 Summary Statistics for VOC Monitoring
Appendix K 2011 Summary Statistics for SNMOC Monitoring
Appendix L 2011 Summary Statistics for Carbonyl Compounds Monitoring
Appendix M 2011 Summary Statistics for PAH Monitoring
Appendix N 2011 Summary Statistics for Metals Monitoring
Appendix O 2011 Summary Statistics for Hexavalent Chromium Monitoring
Appendix P Risk Factors Used Throughout the 2011 NMP Report
Appendix Q Glossary of Terms
xix
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LIST OF FIGURES
2-1 Locations of the 2011 National Monitoring Programs Monitoring Sites 2-3
4-la Coefficient of Variation Analysis of Acenaphthene Across 23 Sites 4-45
4-lb Inter-Site Variability for Acenaphthene 4-45
4-2a Coefficient of Variation Analysis of Acetaldehyde Across 24 Sites 4-46
4-2b Inter-Site Variability for Acetaldehyde 4-46
4-3a Coefficient of Variation Analysis of Acrylonitrile Across 22 Sites 4-47
4-3b Inter-Site Variability for Acrylonitrile 4-47
4-4a Coefficient of Variation Analysis of Arsenic Across 14 Sites 4-48
4-4b Inter-Site Variability for Arsenic 4-48
4-5a Coefficient of Variation Analysis of Benzene Across 23 Sites 4-49
4-5b Inter-Site Variability for Benzene 4-49
4-6a Coefficient of Variation Analysis of Benzo(a)pyrene Across 23 Sites 4-50
4-6b Inter-Site Variability for Benzo(a)pyrene 4-50
4-7a Coefficient of Variation Analysis of Beryllium Across 14 Sites 4-51
4-7b Inter-Site Variability for Beryllium 4-51
4-8a Coefficient of Variation Analysis of 1,3-Butadiene Across 23 Sites 4-52
4-8b Inter-Site Variability for 1,3-Butadiene 4-52
4-9a Coefficient of Variation Analysis of Cadmium Across 14 Sites 4-53
4-9b Inter-Site Variability for Cadmium 4-53
4-10a Coefficient of Variation Analysis of Carbon Tetrachloride Across 23 Sites 4-54
4-1 Ob Inter-Site Variability for Carbon Tetrachloride 4-54
4-lla Coefficient of Variation Analysis of Chloroform Across 23 Sites 4-55
4-llb Inter-Site Variability for Chloroform 4-55
4-12a Coefficient of Variation Analysis ofp-Dichlorobenzene Across 23 Sites 4-56
4-12b Inter-Site Variability for/>-Dichlorobenzene 4-56
4-13a Coefficient of Variation Analysis of 1,2-Dichloroethane Across 23 Sites 4-57
4-13b Inter-Site Variability for 1,2-Dichloroethane 4-57
4-14a Coefficient of Variation Analysis of Ethylbenzene Across 23 Sites 4-58
4-14b Inter-Site Variability for Ethylbenzene 4-58
4-15a Coefficient of Variation Analysis of Fluorene Across 23 Sites 4-59
4-15b Inter-Site Variability for Fluorene 4-59
4-16a Coefficient of Variation Analysis of Formaldehyde Across 24 Sites 4-60
4-16b Inter-Site Variability for Formaldehyde 4-60
4-17a Coefficient of Variation Analysis of Hexachloro-1,3-butadiene Across 23 Sites 4-61
4-17b Inter-Site Variability for Hexachloro-1,3-butadiene 4-61
4-18a Coefficient of Variation Analysis of Hexavalent Chromium Across 22 Sites 4-62
4-18b Inter-Site Variability for Hexavalent Chromium 4-62
4-19a Coefficient of Variation Analysis of Lead Across 14 Sites 4-63
4-19b Inter-Site Variability for Lead 4-63
4-20a Coefficient of Variation Analysis of Manganese Across 14 Sites 4-64
4-20b Inter-Site Variability for Manganese 4-64
4-21a Coefficient of Variation Analysis of Naphthalene Across 23 Sites 4-65
4-21b Inter-Site Variability for Naphthalene 4-65
xx
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LIST OF FIGURES (Continued)
Page
4-22a Coefficient of Variation Analysis of Nickel Across 14 Sites 4-66
4-22b Inter-Site Variability for Nickel 4-66
4-23a Coefficient of Variation Analysis of Tetrachloroethylene Across 23 Sites 4-67
4-23b Inter-Site Variability for Tetrachloroethylene 4-67
4-24a Coefficient of Variation Analysis of Trichloroethylene Across 23 Sites 4-68
4-24b Inter-Site Variability for Trichloroethylene 4-68
4-25a Coefficient of Variation Analysis of Vinyl Chloride Across 23 Sites 4-69
4-25b Inter-Site Variability for Vinyl Chloride 4-69
4-26 Comparison of Average Quarterly Acenaphthene Concentrations 4-73
4-27 Comparison of Average Quarterly Acetaldehyde Concentrations 4-74
4-28 Comparison of Average Quarterly Acrylonitrile Concentrations 4-75
4-29a Comparison of Average Quarterly Arsenic (PMi0) Concentrations 4-76
4-29b Comparison of Average Quarterly Arsenic (TSP) Concentrations 4-77
4-30 Comparison of Average Quarterly Benzene Concentrations 4-78
4-31 Comparison of Average Quarterly Benzo(a)pyrene Concentrations 4-79
4-32a Comparison of Average Quarterly Beryllium (PMio) Concentrations 4-80
4-32b Comparison of Average Quarterly Beryllium (TSP) Concentrations 4-81
4-33 Comparison of Average Quarterly 1,3-Butadiene Concentrations 4-82
4-34a Comparison of Average Quarterly Cadmium (PMio) Concentrations 4-83
4-34b Comparison of Average Quarterly Cadmium (TSP) Concentrations 4-84
4-3 5 Comparison of Average Quarterly Carbon Tetrachloride Concentrations 4-85
4-36 Comparison of Average Quarterly Chloroform Concentrations 4-86
4-37 Comparison of Average Quarterly p-Dich\orobenzene Concentrations 4-87
4-3 8 Comparison of Average Quarterly 1,2-Dichloroethane Concentrations 4-88
4-39 Comparison of Average Quarterly Ethylbenzene Concentrations 4-89
4-40 Comparison of Average Quarterly Fluorene Concentrations 4-90
4-41 Comparison of Average Quarterly Formaldehyde Concentrations 4-91
4-42 Comparison of Average Quarterly Hexachloro-1,3-butadiene Concentrations 4-92
4-43 Comparison of Average Quarterly Hexavalent Chromium Concentrations 4-93
4-44a Comparison of Average Quarterly Lead (PMio) Concentrations 4-94
4-44b Comparison of Average Quarterly Lead (TSP) Concentrations 4-95
4-45a Comparison of Average Quarterly Manganese (PMio) Concentrations 4-96
4-45b Comparison of Average Quarterly Manganese (TSP) Concentrations 4-97
4-46 Comparison of Average Quarterly Naphthalene Concentrations 4-98
4-47a Comparison of Average Quarterly Nickel (PMio) Concentrations 4-99
4-47b Comparison of Average Quarterly Nickel (TSP) Concentrations 4-100
4-48 Comparison of Average Quarterly Tetrachloroethylene Concentrations 4-101
4-49 Comparison of Average Quarterly Trichloroethylene Concentrations 4-102
4-50 Comparison of Average Quarterly Vinyl Chloride Concentrations 4-103
5-1 Phoenix, Arizona (PXSS) Monitoring Site 5-2
5-2 South Phoenix, Arizona (SPAZ) Monitoring Site 5-3
5-3 NEI Point Sources Located Within 10 Miles of PXSS and SPAZ 5-4
5-4 2011 Composite Back Trajectory Map for PXSS 5-11
5-5 Back Trajectory Cluster Map for PXSS 5-11
xxi
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LIST OF FIGURES (Continued)
Page
5-6 2011 Composite Back Trajectory Map for SPAZ 5-12
5-7 Back Trajectory Cluster Map for SPAZ 5-12
5-8 Wind Roses for the Phoenix Sky Harbor International Airport Weather Station
nearPXSS 5-14
5-9 Wind Roses for the Phoenix Sky Harbor International Airport Weather Station
near SPAZ 5-15
5-10 Program vs. Site-Specific Average Arsenic (PMio) Concentration 5-24
5-11 Program vs. Site-Specific Average Benzene Concentrations 5-24
5-12 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 5-24
5-13 Program vs. Site-Specific Average 1,3-Butadiene Concentrations 5-25
5-14 Program vs. Site-Specific Average Hexavalent Chromium Concentration 5-25
5-15 Program vs. Site-Specific Average Lead (PMio) Concentration 5-25
5-16 Program vs. Site-Specific Average Manganese (PMio) Concentration 5-26
5-17 Program vs. Site-Specific Average Naphthalene Concentration 5-26
5-18 Annual Statistical Metrics for Arsenic (PMio) Concentrations Measured at PXSS 5-29
5-19 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at PXSS 5-29
5-20 Annual Statistical Metrics for Lead (PMio) Concentrations Measured at PXSS 5-30
5-21 Annual Statistical Metrics for Manganese (PMio) Concentrations Measured
at PXSS 5-30
6-1 Los Angeles, California (CELA) Monitoring Site 6-2
6-2 NEI Point Sources Located Within 10 Miles of CELA 6-3
6-3 Rubidoux, California (RUCA) Monitoring Site 6-4
6-4 NEI Point Sources Located Within 10 Miles of RUCA 6-5
6-5 San Jose, California (SJJCA) Monitoring Site 6-6
6-6 NEI Point Sources Located Within 10 Miles of SJJCA 6-7
6-7 2011 Composite Back Trajectory Map for CELA 6-15
6-8 Back Trajectory Cluster Map for CELA 6-15
6-9 2011 Composite Back Trajectory Map for RUCA 6-16
6-10 Back Trajectory Cluster Map for RUCA 6-16
6-11 2011 Composite Back Trajectory Map for SJJCA 6-17
6-12 Back Trajectory Cluster Map for SJJCA 6-17
6-13 Wind Roses for the Downtown Los Angeles/USC Campus Weather Station
near CELA 6-20
6-14 Wind Roses for the Riverside Municipal Airport Weather Station near RUCA 6-21
6-15 Wind Roses for the San Jose International Airport Weather Station near SJJCA 6-22
6-16 Program vs. Site-Specific Average Arsenic (PMio) Concentration 6-29
6-17 Program vs. Site-Specific Average Benzo(a)pyrene Concentrations 6-29
6-18 Program vs. Site-Specific Average Lead (PMio) Concentration 6-29
6-19 Program vs. Site-Specific Average Manganese (PMio) Concentration 6-30
6-20 Program vs. Site-Specific Average Naphthalene Concentrations 6-30
7-1 Grand Junction, Colorado (GPCO) Monitoring Site 7-2
7-2 NEI Point Sources Located Within 10 Miles of GPCO 7-3
xxii
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LIST OF FIGURES (Continued)
Page
7-3 Battlement Mesa, Colorado (BMCO) Monitoring Site 7-4
7-4 Silt, Colorado (BRCO) Monitoring Site 7-5
7-5 Parachute, Colorado (PACO) Monitoring Site 7-6
7-6 Rifle, Colorado (RICO) Monitoring Site 7-7
7-7 NEI Point Sources Located Within 10 Miles of BMCO, BRCO, PACO, and RICO 7-8
7-8 2011 Composite Back Trajectory Map for GPCO 7-17
7-9 Back Trajectory Cluster Map for GPCO 7-17
7-10 2011 Composite Back Trajectory Map for BMCO 7-18
7-11 Back Trajectory Cluster Map for BMCO 7-18
7-12 2011 Composite Back Trajectory Map for BRCO 7-19
7-13 Back Trajectory Cluster Map for BRCO 7-19
7-14 2011 Composite Back Trajectory Map for PACO 7-20
7-15 Back Trajectory Cluster Map for PACO 7-20
7-16 2011 Composite Back Trajectory Map for RICO 7-21
7-17 Back Trajectory Cluster Map for RICO 7-21
7-18 Wind Roses for the Walker Field Airport Weather Station near GPCO 7-23
7-19 Wind Roses for the Garfield County Regional Airport near BMCO 7-24
7-20 Wind Roses for the Garfield County Regional Airport near BRCO 7-25
7-21 Wind Roses for the Garfield County Regional Airport near PACO 7-26
7-22 Wind Roses for the Garfield County Regional Airport near RICO 7-27
7-23 Program vs. Site-Specific Average Acetaldehyde Concentration 7-37
7-24a Program vs. Site-Specific Average Benzene (Method TO-15) Concentration 7-37
7-24b Program vs. Site-Specific Average Benzene (SNMOC) Concentrations 7-38
7-25 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 7-38
7-26a Program vs. Site-Specific Average 1,3-Butadiene (Method TO-15) Concentration 7-38
7-26b Program vs. Site-Specific Average 1,3-Butadiene (SNMOC) Concentrations 7-39
7-27 Program vs. Site-Specific Average Formaldehyde Concentration 7-39
7-28 Program vs. Site-Specific Average Hexavalent Chromium Concentration 7-39
7-29 Program vs. Site-Specific Average Naphthalene Concentration 7-40
7-30 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at GPCO 7-43
7-31 Annual Statistical Metrics for Benzene Concentrations Measured at GPCO 7-43
7-32 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at GPCO 7-44
7-33 Annual Statistical Metrics for Formaldehyde Concentrations Measured at GPCO 7-44
7-34 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at GPCO 7-45
8-1 Washington, D.C. (WADC) Monitoring Site 8-2
8-2 NEI Point Sources Located Within 10 Miles of WADC 8-3
8-3 2011 Composite Back Trajectory Map for WADC 8-9
8-4 Back Trajectory Cluster Map for WADC 8-9
8-5 Wind Roses for the Ronald Reagan Washington National Airport Weather Station
near WADC 8-11
8-6 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 8-15
8-7 Program vs. Site-Specific Average Hexavalent Chromium Concentration 8-15
8-8 Program vs. Site-Specific Average Naphthalene Concentration 8-16
xxiii
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LIST OF FIGURES (Continued)
Page
8-9 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured at
WADC 8-17
9-1 St. Petersburg, Florida (AZFL) Monitoring Site 9-2
9-2 Pinellas Park, Florida (SKFL) Monitoring Site 9-3
9-3 Plant City, Florida (SYFL) Monitoring Site 9-4
9-4 NEI Point Sources Located Within 10 Miles of the Tampa/St. Petersburg, Florida
Monitoring Sites 9-5
9-5 Winter Park, Florida (ORFL) Monitoring Site 9-6
9-6 Orlando, Florida (PAFL) Monitoring Site 9-7
9-7 NEI Point Sources Located Within 10 Miles of ORFL and PAFL 9-8
9-8 2011 Composite Back Trajectory Map for AZFL 9-17
9-9 Back Trajectory Cluster Map for AZFL 9-17
9-10 2011 Composite Back Trajectory Map for SKFL 9-18
9-11 Back Trajectory Cluster Map for SKFL 9-18
9-12 2011 Composite Back Trajectory Map for SYFL 9-19
9-13 Back Trajectory Cluster Map for SYFL 9-19
9-14 2011 Composite Back Trajectory Map for ORFL 9-20
9-15 Back Trajectory Cluster Map for ORFL 9-20
9-16 2011 Composite Back Trajectory Map for PAFL 9-21
9-17 Back Trajectory Cluster Map for PAFL 9-21
9-18 Wind Roses for the St. Petersburg/Whitted Airport Weather Station near AZFL 9-24
9-19 Wind Roses for the St. Petersburg/Clearwater International Airport Weather
Station near SKFL 9-25
9-20 Wind Roses for the Plant City Municipal Airport Weather Station near SYFL 9-26
9-21 Wind Roses for the Orlando Executive Airport Weather Station near ORFL 9-27
9-22 Wind Roses for the Orlando Executive Airport Weather Station near PAFL 9-28
9-23 Program vs. Site-Specific Average Acetaldehyde Concentrations 9-37
9-24 Program vs. Site-Specific Average Arsenic (PMio) Concentration 9-37
9-25 Program vs. Site-Specific Average Benzo(a)Pyrene Concentrations 9-38
9-26 Program vs. Site-Specific Average Formaldehyde Concentrations 9-38
9-27 Program vs. Site-Specific Average Hexavalent Chromium Concentrations 9-39
9-28 Program vs. Site-Specific Average Lead (PMio) Concentration 9-39
9-29 Program vs. Site-Specific Average Manganese (PMio) Concentration 9-39
9-30 Program vs. Site-Specific Average Naphthalene Concentrations 9-40
9-31 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at AZFL 9-42
9-32 Annual Statistical Metrics for Formaldehyde Concentrations Measured at AZFL 9-43
9-33 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at ORFL 9-43
9-34 Annual Statistical Metrics for Formaldehyde Concentrations Measured at ORFL 9-44
9-35 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at SKFL 9-44
9-36 Annual Statistical Metrics for Formaldehyde Concentrations Measured at SKFL 9-45
9-37 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at SYFL 9-45
9-38 Annual Statistical Metrics for Formaldehyde Concentrations Measured at SYFL 9-46
9-39 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at SYFL 9-46
xxiv
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LIST OF FIGURES (Continued)
Page
10-1 Decatur, Georgia (SDGA) Monitoring Site 10-2
10-2 NEI Point Sources Located Within 10 Miles of SDGA 10-3
10-3 2011 Composite Back Trajectory Map for SDGA 10-9
10-4 Back Trajectory Cluster Map for SDGA 10-9
10-5 Wind Roses for the Hartsfield International Airport Weather Station near SDGA 10-11
10-6 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 10-15
10-7 Program vs. Site-Specific Average Hexavalent Chromium Concentration 10-15
10-8 Program vs. Site-Specific Average Naphthalene Concentration 10-16
10-9 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at SDGA 10-17
11-1 Northbrook, Illinois (NBIL) Monitoring Site 11-2
11-2 Schiller Park, Illinois (SPIL) Monitoring Site 11-3
11-3 NEI Point Sources Located Within 10 Miles of NBIL and SPIL 11-4
11-4 2011 Composite Back Trajectory Map for NBIL 11-10
11-5 Back Trajectory Cluster Map for NBIL 11-11
11-6 2011 Composite Back Trajectory Map for SPIL 11-11
11-7 Back Trajectory Cluster Map for SPIL 11-12
11-8 Wind Roses for the Palwaukee Municipal Airport Weather Station near NBIL 11-14
11-9 Wind Roses for the O'Hare International Airport Weather Station near SPIL 11-15
11-10 Program vs. Site-Specific Average Acetaldehyde Concentrations 11-25
11-11 Program vs. Site-Specific Average Arsenic (PMio) Concentration 11-26
11-12 Program vs. Site-Specific Average Benzene Concentrations 11-26
11-13 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 11-26
11-14 Program vs. Site-Specific Average 1,3-Butadiene Concentrations 11-27
11-15 Program vs. Site-Specific Average Formaldehyde Concentrations 11-27
11-16 Program vs. Site-Specific Average Hexavalent Chromium Concentration 11-27
11-17 Program vs. Site-Specific Average Lead (PMio) Concentration 11-28
11-18 Program vs. Site-Specific Average Manganese (PMio) Concentration 11-28
11-19 Program vs. Site-Specific Average Naphthalene Concentration 11 -28
11-20 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at NBIL 11-31
11-21 Annual Statistical Metrics for Arsenic (PMio) Concentrations Measured at NBIL.... 11-32
11 -22 Annual Statistical Metrics for Benzene Concentrations Measured at NBIL 11-32
11-23 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at NBIL 11-33
11-24 Annual Statistical Metrics for Formaldehyde Concentrations Measured at NBIL 11-33
11-25 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at NBIL 11-34
11 -26 Annual Statistical Metrics for Lead (PMio) Concentrations Measured at NBIL 11-34
11-27 Annual Statistical Metrics for Manganese (PMio) Concentrations Measured
at NBIL 11-35
11 -28 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at SPIL 11-35
11-29 Annual Statistical Metrics for Benzene Concentrations Measured at SPIL 11-36
11-30 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at SPIL 11-36
11-31 Annual Statistical Metrics for Formaldehyde Concentrations Measured at SPIL 11-37
xxv
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LIST OF FIGURES (Continued)
Page
12-1 Gary, Indiana (INDEM) Monitoring Site 12-2
12-2 NEI Point Sources Located Within 10 Miles of INDEM 12-3
12-3 Indianapolis, Indiana (WPIN) Monitoring Site 12-4
12-4 NEI Point Sources Located Within 10 Miles of WPIN 12-5
12-5 2011 Composite Back Trajectory Map for INDEM 12-12
12-6 Back Trajectory Cluster Map for INDEM 12-12
12-7 2011 Composite Back Trajectory Map for WPIN 12-13
12-8 Back Trajectory Cluster Map for WPIN 12-13
12-9 Wind Roses for the Lansing Municipal Airport Weather Station near INDEM 12-15
12-10 Wind Roses for the Indianapolis International Airport Weather Station near WPIN . 12-16
12-11 Program vs. Site-Specific Average Acetaldehyde Concentration 12-21
12-12 Program vs. Site-Specific Average Formaldehyde Concentration 12-21
12-13 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at INDEM... 12-23
12-14 Annual Statistical Metrics for Formaldehyde Concentrations Measured at
INDEM 12-23
13-1 Grayson, Kentucky (GLKY) Monitoring Site 13-2
13-2 NEI Point Sources Located Within 10 Miles of GLKY 13-3
13-3 2011 Composite Back Trajectory Map for GLKY 13-9
13-4 Back Trajectory Cluster Map for GLKY 13-9
13-5 Wind Roses for the Tri-State/MJ. Ferguson Field Airport Weather Station near
GLKY 13-11
13-6 Program vs. Site-Specific Average Benzene Concentration 13-17
13-7 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 13-17
13-8 Program vs. Site-Specific Average 1,3-Butadiene Concentration 13-17
13-9 Program vs. Site-Specific Average Hexavalent Chromium Concentration 13-18
13-10 Program vs. Site-Specific Average Naphthalene Concentration 13-18
14-1 Boston, Massachusetts (BOMA) Monitoring Site 14-2
14-2 NEI Point Sources Located Within 10 Miles of BOMA 14-3
14-3 2011 Composite Back Trajectory Map for BOMA 14-9
14-4 Back Trajectory Cluster Map for BOMA 14-9
14-5 Wind Roses for the Logan International Airport Weather Station near BOMA 14-12
14-6 Program vs. Site-Specific Average Arsenic (PMio) Concentration 14-17
14-7 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 14-17
14-8 Program vs. Site-Specific Average Hexavalent Chromium Concentration 14-17
14-9 Program vs. Site-Specific Average Lead (PMio) Concentration 14-18
14-10 Program vs. Site-Specific Average Manganese (PMio) Concentration 14-18
14-11 Program vs. Site-Specific Average Naphthalene Concentration 14-18
14-12 Annual Statistical Metrics for Arsenic (PMio) Concentrations Measured at BOMA . 14-20
14-13 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at BOMA 14-21
14-14 Annual Statistical Metrics for Lead (PMio) Concentrations Measured at BOMA 14-21
14-15 Annual Statistical Metrics for Manganese (PMio) Concentrations Measured
at BOMA 14-22
xxvi
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LIST OF FIGURES (Continued)
Page
15-1 Dearborn, Michigan (DEMI) Monitoring Site 15-2
15-2 River Rouge, Michigan (RRMI) Monitoring Site 15-3
15-3 Detroit, Michigan (SWMI) Monitoring Site 15-4
15-4 NEI Point Sources Located Within 10 Miles of DEMI, RRMI, and SWMI 15-5
15-5 2011 Composite Back Trajectory Map for DEMI 15-12
15-6 Back Trajectory Cluster Map for DEMI 15-12
15-7 2011 Composite Back Trajectory Map for RRMI 15-13
15-8 Back Trajectory Cluster Map for RRMI 15-13
15-9 2011 Composite Back Trajectory Map for SWMI 15-14
15-10 Wind Roses for the Detroit City Airport Weather Station near DEMI 15-16
15-11 Wind Roses for the Detroit City Airport Weather Station near RRMI 15-17
15-12 Wind Roses for the Detroit City Airport Weather Station near SWMI 15-18
15-13 Program vs. Site-Specific Average Acetaldehyde Concentrations 15-26
15-14 Program vs. Site-Specific Average Benzene Concentration 15-27
15-15 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 15-27
15-16 Program vs. Site-Specific Average 1,3-Butadiene Concentration 15-27
15-17 Program vs. Site-Specific Average Formaldehyde Concentrations 15-28
15-18 Program vs. Site-Specific Average Hexavalent Chromium Concentration 15-28
15-19 Program vs. Site-Specific Average Naphthalene Concentration 15-28
15-20 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at DEMI 15-31
15-21 Annual Statistical Metrics for Benzene Concentrations Measured at DEMI 15-31
15-22 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at DEMI 15-32
15-23 Annual Statistical Metrics for Formaldehyde Concentrations Measured at DEMI 15-32
15-24 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at DEMI 15-33
16-1 St. Louis, Missouri (S4MO) Monitoring Site 16-2
16-2 NEI Point Sources Located Within 10 Miles of S4MO 16-3
16-3 2011 Composite Back Trajectory Map for S4MO 16-9
16-4 Back Trajectory Cluster Map for S4MO 16-9
16-5 Wind Roses for the St. Louis Downtown Airport Weather Station near S4MO 16-12
16-6 Program vs. Site-Specific Average Acetaldehyde Concentration 16-19
16-7 Program vs. Site-Specific Average Arsenic (PMio) Concentration 16-19
16-8 Program vs. Site-Specific Average Benzene Concentration 16-20
16-9 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 16-20
16-10 Program vs. Site-Specific Average 1,3-Butadiene Concentration 16-20
16-11 Program vs. Site-Specific Average Formaldehyde Concentration 16-21
16-12 Program vs. Site-Specific Average Hexavalent Chromium Concentration 16-21
16-13 Program vs. Site-Specific Average Lead (PMio) Concentration 16-21
16-14 Program vs. Site-Specific Average Manganese (PMio) Concentration 16-22
16-15 Program vs. Site-Specific Average Naphthalene Concentration 16-22
16-16 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at S4MO 16-25
16-17 Annual Statistical Metrics for Arsenic (PMio) Concentrations Measured at S4MO... 16-25
16-18 Annual Statistical Metrics for Benzene Concentrations Measured at S4MO 16-26
16-19 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at S4MO 16-26
xxvii
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LIST OF FIGURES (Continued)
Page
16-20 Annual Statistical Metrics for Formaldehyde Concentrations Measured at S4MO .... 16-27
16-21 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
atS4MO 16-27
16-22 Annual Statistical Metrics for Lead (PMi0) Concentrations Measured at S4MO 16-28
16-23 Annual Statistical Metrics for Manganese (PMio) Concentrations Measured
atS4MO 16-28
17-1 Chester, New Jersey (CHNJ) Monitoring Site 17-2
17-2 NEI Point Sources Located Within 10 Miles of CHNJ 17-3
17-3 Elizabeth, New Jersey (ELNJ) Monitoring Site 17-4
17-4 New Brunswick, New Jersey (NBNJ) Monitoring Site 17-5
17-5 NEI Point Sources Located Within 10 Miles of ELNJ and NBNJ 17-6
17-6 Paterson, New Jersey (PANJ) Monitoring Site 17-7
17-7 NEI Point Sources Located Within 10 Miles of PANJ 17-8
17-8 2011 Composite Back Trajectory Map for CHNJ 17-16
17-9 Back Trajectory Cluster Map for CHNJ 17-16
17-10 2011 Composite Back Trajectory Map for ELNJ 17-17
17-11 Back Trajectory Cluster Map for ELNJ 17-17
17-12 2011 Composite Back Trajectory Map for NBNJ 17-18
17-13 Back Trajectory Cluster Map for NBNJ 17-18
17-14 2011 Composite Back Trajectory Map for PANJ 17-19
17-15 Wind Roses for the Summerville-Somerset Airport Weather Station near CHNJ 17-21
17-16 Wind Roses for the Newark International Airport Weather Station near ELNJ 17-22
17-17 Wind Roses for the Summerville-Somerset Airport Weather Station near NBNJ 17-23
17-18 Wind Roses for the Essex County Airport Weather Station near PANJ 17-24
17-19 Program vs. Site-Specific Average Acetaldehyde Concentrations 17-36
17-20 Program vs. Site-Specific Average Benzene Concentrations 17-37
17-21 Program vs. Site-Specific Average 1,3-Butadiene Concentrations 17-37
17-22 Program vs. Site-Specific Average Formaldehyde Concentrations 17-38
17-23 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at CHNJ 17-40
17-24 Annual Statistical Metrics for Benzene Concentrations Measured at CHNJ 17-40
17-25 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at CHNJ 17-41
17-26 Annual Statistical Metrics for Formaldehyde Concentrations Measured at CHNJ 17-41
17-27 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at ELNJ 17-42
17-28 Annual Statistical Metrics for Benzene Concentrations Measured at ELNJ 17-42
17-29 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at ELNJ 17-43
17-30 Annual Statistical Metrics for Formaldehyde Concentrations Measured at ELNJ 17-43
17-31 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at NBNJ 17-44
17-32 Annual Statistical Metrics for Benzene Concentrations Measured at NBNJ 17-44
17-33 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at NBNJ 17-45
17-34 Annual Statistical Metrics for Formaldehyde Concentrations Measured at NBNJ 17-45
18-1 New York City, New York (MONY) Monitoring Site 18-2
18-2 NEI Point Sources Located Within 10 Miles of MONY 18-3
18-3 Rochester, New York (ROCH) Monitoring Site 18-4
xxviii
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LIST OF FIGURES (Continued)
Page
18-4 NEI Point Sources Located Within 10 Miles of ROCH 18-5
18-5 2011 Composite Back Trajectory Map for MONY 18-12
18-6 Back Trajectory Cluster Map for MONY 18-12
18-7 2011 Composite Back Trajectory Map for ROCH 18-13
18-8 Back Trajectory Cluster Map for ROCH 18-13
18-9 Wind Roses for the Central Park Weather Station near MONY 18-16
18-10 Wind Roses for the Greater Rochester International Airport Weather Station
near ROCH 18-17
18-11 Program vs. Site-Specific Average Benzo(a)pyrene Concentrations 18-23
18-12 Program vs. Site-Specific Average Hexavalent Chromium Concentrations 18-23
18-13 Program vs. Site-Specific Average Naphthalene Concentrations 18-24
19-1 Tulsa, Oklahoma (TOOK) Monitoring Site 19-2
19-2 Tulsa, Oklahoma (TMOK) Monitoring Site 19-3
19-3 NEI Point Sources Located Within 10 Miles of TMOK and TOOK 19-4
19-4 Pryor Creek, Oklahoma (PROK) Monitoring Site 19-5
19-5 NEI Point Sources Located Within 10 Miles of PROK 19-6
19-6 Midwest City, Oklahoma (MWOK) Monitoring Site 19-7
19-7 Oklahoma City, Oklahoma (OCOK) Monitoring Site 19-8
19-8 NEI Point Sources Located Within 10 Miles of MWOK and OCOK 19-9
19-9 2011 Composite Back Trajectory Map for TOOK 19-17
19-10 Back Trajectory Cluster Map for TOOK 19-17
19-11 2011 Composite Back Trajectory Map for TMOK 19-18
19-12 Back Trajectory Cluster Map for TMOK 19-18
19-13 2011 Composite Back Trajectory Map for PROK 19-19
19-14 Back Trajectory Cluster Map for PROK 19-19
19-15 2011 Composite Back Trajectory Map for MWOK 19-20
19-16 Back Trajectory Cluster Map for MWOK 19-20
19-17 2011 Composite Back Trajectory Map for OCOK 19-21
19-18 Back Trajectory Cluster Map for OCOK 19-21
19-19 Wind Roses for the Richard Lloyd Jones Jr. Airport Weather Station near TOOK.... 19-24
19-20 Wind Roses for the Tulsa International Airport Weather Station near TMOK 19-25
19-21 Wind Roses for the Claremore Regional Airport Weather Station near PROK 19-26
19-22 Wind Roses for the Tinker Air Force Base Airport Weather Station near MWOK.... 19-27
19-23 Wind Roses for the Wiley Post Airport Weather Station near OCOK 19-28
19-24 Program vs. Site-Specific Average Acetaldehyde Concentrations 19-46
19-25 Program vs. Site-Specific Average Arsenic (TSP) Concentrations 19-47
19-26 Program vs. Site-Specific Average Benzene Concentrations 19-48
19-27 Program vs. Site-Specific Average 1,3-Butadiene Concentrations 19-49
19-28 Program vs. Site-Specific Average Formaldehyde Concentrations 19-50
19-29 Program vs. Site-Specific Average Lead (TSP) Concentrations 19-51
19-30 Program vs. Site-Specific Average Manganese (TSP) Concentrations 19-52
19-31 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at TOOK 19-54
19-32 Annual Statistical Metrics for Arsenic (TSP) Concentrations Measured at TOOK.... 19-55
19-33 Annual Statistical Metrics for Benzene Concentrations Measured at TOOK 19-55
xxix
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LIST OF FIGURES (Continued)
Page
19-34 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at TOOK .... 19-56
19-35 Annual Statistical Metrics for Formaldehyde Concentrations Measured at TOOK.... 19-56
19-36 Annual Statistical Metrics for Lead (TSP) Concentrations Measured at TOOK 19-57
19-37 Annual Statistical Metrics for Manganese (TSP) Concentrations Measured
at TOOK 19-57
20-1 Providence, Rhode Island (PRRI) Monitoring Site 20-2
20-2 NEI Point Sources Located Within 10 Miles of PRRI 20-3
20-3 2011 Composite Back Trajectory Map for PRRI 20-9
20-4 Back Trajectory Cluster Map for PRRI 20-9
20-5 Wind Roses for the T.F. Green State Airport Weather Station near PRRI 20-12
20-6 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 20-16
20-7 Program vs. Site-Specific Average Hexavalent Chromium Concentration 20-16
20-8 Program vs. Site-Specific Average Naphthalene Concentration 20-17
20-9 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at PRRI 20-18
21-1 Chesterfield, South Carolina (CHSC) Monitoring Site 21-2
21-2 NEI Point Sources Located Within 10 Miles of CHSC 21-3
21-3 2011 Composite Back Trajectory Map for CHSC 21-9
21-4 Back Trajectory Cluster Map for CHSC 21-9
21-5 Wind Roses for the Monroe Airport Weather Station near CHSC 21-11
21-6 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 21-15
21-7 Program vs. Site-Specific Average Hexavalent Chromium Concentration 21-15
21-8 Program vs. Site-Specific Average Naphthalene Concentration 21-16
21-9 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at CHSC 21-17
22-1 Sioux Falls, South Dakota (SSSD) Monitoring Site 22-2
22-2 NEI Point Sources Located Within 10 Miles of SSSD 22-3
22-3 Union County, South Dakota (UCSD) Monitoring Site 22-4
22-4 NEI Point Sources Located Within 10 Miles of UCSD 22-5
22-5 2011 Composite Back Trajectory Map for SSSD 22-12
22-6 Back Trajectory Cluster Map for SSSD 22-12
22-7 2011 Composite Back Trajectory Map for UCSD 22-13
22-8 Back Trajectory Cluster Map for UCSD 22-13
22-9 Wind Roses for the Joe Foss Field Airport Weather Station near SSSD 22-16
22-10 Wind Roses for the Sioux Gateway Airport Weather Station near UCSD 22-17
22-11 Program vs. Site-Specific Average Acetaldehyde Concentrations 22-24
22-12 Program vs. Site-Specific Average Benzene Concentrations 22-24
22-13 Program vs. Site-Specific Average 1,3-Butadiene Concentrations 22-25
22-14 Program vs. Site-Specific Average Formaldehyde Concentrations 22-25
23-1 Deer Park, Texas (CAMS 35) Monitoring Site 23-2
23-2 NEI Point Sources Located Within 10 Miles of CAMS 35 23-3
XXX
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LIST OF FIGURES (Continued)
Page
23-3 Karnack, Texas (CAMS 85) Monitoring Site 23-4
23-4 NEI Point Sources Located Within 10 Miles of CAMS 85 23-5
23-5 2011 Composite Back Trajectory Map for CAMS 35 23-12
23-6 Back Trajectory Cluster Map for CAMS 35 23-12
23-7 2011 Composite Back Trajectory Map for CAMS 85 23-13
23-8 Back Trajectory Cluster Map for CAMS 85 23-13
23-9 Wind Roses for the William P. Hobby Airport Weather Station near CAMS 35 23-15
23-10 Wind Roses for the Shreveport Regional Airport Weather Station near CAMS 85.... 23-16
23-11 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 23-22
23-12 Program vs. Site-Specific Average Hexavalent Chromium Concentrations 23-22
23-13 Program vs. Site-Specific Average Naphthalene Concentration 23-22
24-1 Bountiful, Utah (BTUT) Monitoring Site 24-2
24-2 NEI Point Sources Located Within 10 Miles of BTUT 24-3
24-3 2011 Composite Back Trajectory Map for BTUT 24-9
24-4 Back Trajectory Cluster Map for BTUT 24-9
24-5 Wind Roses for the Salt Lake City International Airport Weather Station near
BTUT 24-12
24-6 Program vs. Site-Specific Average Acetaldehyde Concentration 24-18
24-7 Program vs. Site-Specific Average Arsenic (PMio) Concentration 24-19
24-8 Program vs. Site-Specific Average Benzene Concentration 24-19
24-9 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 24-19
24-10 Program vs. Site-Specific Average 1,3-Butadiene Concentration 24-20
24-11 Program vs. Site-Specific Average Formaldehyde Concentration 24-20
24-12 Program vs. Site-Specific Average Hexavalent Chromium Concentration 24-20
24-13 Program vs. Site-Specific Average Lead (PMio) Concentration 24-21
24-14 Program vs. Site-Specific Average Manganese (PMio) Concentration 24-21
24-15 Program vs. Site-Specific Average Naphthalene Concentration 24-21
24-16 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at BTUT 24-24
24-17 Annual Statistical Metrics for Arsenic (PMio) Concentrations Measured at BTUT... 24-24
24-18 Annual Statistical Metrics for Benzene Concentrations Measured at BTUT 24-25
24-19 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at BTUT 24-25
24-20 Annual Statistical Metrics for Formaldehyde Concentrations Measured at BTUT .... 24-26
24-21 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at BTUT 24-26
24-22 Annual Statistical Metrics for Lead (PMio) Concentrations Measured at BTUT 24-27
24-23 Annual Statistical Metrics for Manganese (PMio) Concentrations Measured
at BTUT 24-27
25-1 Burlington, Vermont (BURVT) Monitoring Site 25-2
25-2 Underbill, Vermont (UNVT) Monitoring Site 25-3
25-3 NEI Point Sources Located Within 10 Miles of BURVT and UNVT 25-4
25-4 Rutland, Vermont (RUVT) Monitoring Site 25-5
25-5 NEI Point Sources Located Within 10 Miles of RUVT 25-6
25-6 2011 Composite Back Trajectory Map for BURVT 25-13
xxxi
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LIST OF FIGURES (Continued)
Page
25-7 Back Trajectory Cluster Map forBURVT 25-13
25-8 2011 Composite Back Trajectory Map for RUVT 25-14
25-9 Back Trajectory Cluster Map for RUVT 25-14
25-10 2011 Composite Back Trajectory Map for UNVT 25-15
25-11 Back Trajectory Cluster Map for UNVT 25-15
25-12 Wind Roses for the Burlington International Airport Weather Station near
BURVT 25-18
25-13 Wind Roses for the Rutland State Airport Weather Station near RUVT 25-19
25-14 Wind Roses for the Morrisville-Stowe State Airport Weather Station near UNVT ... 25-20
25-15 Program vs. Site-Specific Average Arsenic (PMio) Concentration 25-30
25-16 Program vs. Site-Specific Average Benzene Concentrations 25-30
25-17 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 25-30
25-18 Program vs. Site-Specific Average 1,3-Butadiene Concentrations 25-31
25-19 Program vs. Site-Specific Average Hexavalent Chromium Concentration 25-31
25-20 Program vs. Site-Specific Average Lead (PMio) Concentration 25-31
25-21 Program vs. Site-Specific Average Manganese (PMio) Concentration 25-32
25-22 Program vs. Site-Specific Average Naphthalene Concentration 25-32
25-23 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at UNVT 25-34
26-1 Richmond, Virginia (RIVA) Monitoring Site 26-2
26-2 NEI Point Sources Located Within 10 Miles of RIVA 26-3
26-3 2011 Composite Back Trajectory Map for RIVA 26-9
26-4 Back Trajectory Cluster Map for RIVA 26-9
26-5 Wind Roses for the Richmond International Airport Weather Station near RIVA 26-11
26-6 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 26-15
26-7 Program vs. Site-Specific Average Hexavalent Chromium Concentration 26-15
26-8 Program vs. Site-Specific Average Naphthalene Concentration 26-16
27-1 Seattle, Washington (SEWA) Monitoring Site 27-2
27-2 NEI Point Sources Located Within 10 Miles of SEWA 27-3
27-3 2011 Composite Back Trajectory Map for SEWA 27-9
27-4 Back Trajectory Cluster Map for SEWA 27-9
27-5 Wind Roses for the Boeing Field/King County International Airport Weather
Station near SEWA 27-11
27-6 Program vs. Site-Specific Average Acetaldehyde Concentration 27-18
27-7 Program vs. Site-Specific Average Arsenic (PMio) Concentration 27-18
27-8 Program vs. Site-Specific Average Benzene Concentration 27-19
27-9 Program vs. Site-Specific Average Benzo(a)pyrene Concentration 27-19
27-10 Program vs. Site-Specific Average 1,3-Butadiene Concentration 27-19
27-11 Program vs. Site-Specific Average Formaldehyde Concentration 27-20
27-12 Program vs. Site-Specific Average Hexavalent Chromium Concentration 27-20
27-13 Program vs. Site-Specific Average Lead (PMio) Concentration 27-20
27-14 Program vs. Site-Specific Average Manganese (PMio) Concentration 27-21
27-15 Program vs. Site-Specific Average Naphthalene Concentration 27-21
xxxii
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LIST OF FIGURES (Continued)
Page
27-16 Annual Statistical Metrics for Acetaldehyde Concentrations Measured at SEWA 27-24
27-17 Annual Statistical Metrics for Arsenic (PMio) Concentrations Measured at
SEWA 27-24
27-18 Annual Statistical Metrics for Benzene Concentrations Measured at SEWA 27-25
27-19 Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at SEWA.... 27-25
27-20 Annual Statistical Metrics for Formaldehyde Concentrations Measured at SEWA.... 27-26
27-21 Annual Statistical Metrics for Hexavalent Chromium Concentrations Measured
at SEWA 27-26
27-22 Annual Statistical Metrics for Lead (PMio) Concentrations Measured at SEWA 27-27
27-23 Annual Statistical Metrics for Manganese (PMio) Concentrations Measured
at SEWA 27-27
28-1 Horicon, Wisconsin (HOWI) Monitoring Site 28-2
28-2 NEI Point Sources Located Within 10 Miles of HOWI 28-3
28-3 2011 Composite Back Trajectory Map for HOWI 28-9
28-4 Back Trajectory Cluster Map for HOWI 28-9
28-5 Wind Roses for the Dodge County Airport Weather Station near HOWI 28-11
28-6 Program vs. Site-Specific Average Hexavalent Chromium Concentration 28-15
xxxin
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LIST OF TABLES
Page
1-1 Organization of the 2011 National Monitoring Programs Report 1-4
2-1 2011 National Monitoring Programs Sites and Past Program Participation 2-4
2-2 Site Characterizing Information for the 2011 National Monitoring Programs Sites 2-7
2-3 2011 VOC Method Detection Limits 2-16
2-4 2011 SNMOC Method Detection Limits 2-17
2-5 2011 Carbonyl Compound Method Detection Limits 2-19
2-6 2011 PAH Method Detection Limits 2-20
2-7 2011 Metals Method Detection Limits 2-21
2-8 2011 Hexavalent Chromium Method Detection Limits 2-22
2-9 2011 Sampling Schedules and Completeness Rates 2-24
2-10 Method Completeness Rates for 2011 2-30
3-1 Overview and Lay out of Data Presented 3-1
3-2 NATTS MQO Core Analytes 3-6
3-3 NATTS MQO Core Analytes Selected for Comparative Analysis 3-16
3-4 POM Groups for PAHs 3-21
4-1 Statistical Summaries of the VOC Concentrations 4-3
4-2 Statistical Summaries of the SNMOC Concentrations 4-6
4-3 Statistical Summaries of the Carbonyl Compound Concentrations 4-9
4-4 Statistical Summaries of the PAH Concentrations 4-10
4-5 Statistical Summaries of the Metals Concentrations 4-11
4-6 Statistical Summary of the Hexavalent Chromium Concentrations 4-12
4-7 Results of the Program-Level Preliminary Risk-Based Screening 4-16
4-8 Site-Specific Risk-Based Screening Comparison 4-19
4-9 Annual Average Concentration Comparison of the VOC Pollutants of Interest 4-22
4-10 Annual Average Concentration Comparison of the Carbonyl Compound Pollutants
of Interest 4-24
4-11 Annual Average Concentration Comparison of the PAH Pollutants of Interest 4-25
4-12 Annual Average Concentration Comparison of the Metals Pollutants of Interest 4-26
4-13 Comparison of Maximum Concentrations vs. ATSDRMRLs 4-31
4-14 Summary of Mobile Source Information by Monitoring Site 4-34
4-15 Greenhouse Gases Measured by Method TO-15 4-105
5-1 Geographical Information for the Arizona Monitoring Sites 5-5
5-2 Population, Motor Vehicle, and Traffic Information for the Arizona Monitoring
Sites 5-7
5-3 Average Meteorological Conditions near the Arizona Monitoring Sites 5-9
5-4 Risk-Based Screening Results for the Arizona Monitoring Sites 5-17
5-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Arizona Monitoring Sites 5-20
5-6 Risk Approximations for the Arizona Monitoring Sites 5-34
xxxiv
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LIST OF TABLES (Continued)
Page
5-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Arizona Monitoring Sites 5-37
5-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Arizona Monitoring
Sites 5-38
6-1 Geographical Information for the California Monitoring Sites 6-8
6-2 Population, Motor Vehicle, and Traffic Information for the California Monitoring
Sites 6-10
6-3 Average Meteorological Conditions near the California Monitoring Sites 6-13
6-4 Risk-Based Screening Results for the California Monitoring Sites 6-25
6-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
California Monitoring Sites 6-27
6-6 Risk Approximations for the California Monitoring Sites 6-33
6-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the California Monitoring Sites 6-3 5
6-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the California Monitoring
Sites 6-37
7-1 Geographical Information for the Colorado Monitoring Sites 7-9
7-2 Population, Motor Vehicle, and Traffic Information for the Colorado Monitoring
Sites 7-12
7-3 Average Meteorological Conditions near the Colorado Monitoring Sites 7-14
7-4 Risk-Based Screening Results for the Colorado Monitoring Sites 7-29
7-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Colorado Monitoring Sites 7-33
7-6 Risk Approximations for the Colorado Monitoring Sites 7-48
7-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Colorado Monitoring Sites 7-52
7-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Colorado Monitoring
Sites 7-55
8-1 Geographical Information for the Washington, D.C. Monitoring Site 8-4
8-2 Population, Motor Vehicle, and Traffic Information for the Washington, D.C.
Monitoring Site 8-5
8-3 Average Meteorological Conditions near the Washington, D.C. Monitoring Site 8-7
8-4 Risk-Based Screening Results for the Washington, D.C. Monitoring Site 8-13
8-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Washington, D.C. Monitoring Site 8-14
8-6 Risk Approximations for the Washington, D.C. Monitoring Site 8-19
8-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Washington, D.C. Monitoring Site 8-21
xxxv
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LIST OF TABLES (Continued)
Page
8-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Washington, D.C.
Monitoring Site 8-22
9-1 Geographical Information for the Florida Monitoring Sites 9-9
9-2 Population, Motor Vehicle, and Traffic Information for the Florida Monitoring
Sites 9-12
9-3 Average Meteorological Conditions near the Florida Monitoring Sites 9-14
9-4 Risk-Based Screening Results for the Florida Monitoring Sites 9-31
9-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Florida Monitoring Sites 9-34
9-6 Risk Approximations for the Florida Monitoring Sites 9-52
9-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Florida Monitoring Sites 9-55
9-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Florida Monitoring
Sites 9-58
10-1 Geographical Information for the Georgia Monitoring Site 10-4
10-2 Population, Motor Vehicle, and Traffic Information for the Georgia Monitoring
Site 10-5
10-3 Average Meteorological Conditions near the Georgia Monitoring Site 10-8
10-4 Risk-Based Screening Results for the Georgia Monitoring Site 10-13
10-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Georgia Monitoring Site 10-14
10-6 Risk Approximations for the Georgia Monitoring Site 10-19
10-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Georgia Monitoring Site 10-21
10-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Georgia Monitoring
Site 10-22
11-1 Geographical Information for the Illinois Monitoring Sites 11-5
11-2 Population, Motor Vehicle, and Traffic Information for the Illinois Monitoring
Sites 11-7
11-3 Average Meteorological Conditions near the Illinois Monitoring Sites 11-9
11-4 Risk-Based Screening Results for the Illinois Monitoring Sites 11-17
11-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Illinois Monitoring Sites 11-20
11-6 Risk Approximations for the Illinois Monitoring Sites 11-44
11-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Illinois Monitoring Sites 11 -47
11-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Illinois Monitoring
Sites 11-48
xxxvi
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LIST OF TABLES (Continued)
Page
12-1 Geographical Information for the Indiana Monitoring Sites 12-6
12-2 Population, Motor Vehicle, and Traffic Information for the Indiana Monitoring
Sites 12-8
12-3 Average Meteorological Conditions near the Indiana Monitoring Sites 12-10
12-4 Risk-Based Screening Results for the Indiana Monitoring Sites 12-18
12-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Indiana Monitoring Sites 12-20
12-6 Risk Approximations for the Indiana Monitoring Sites 12-26
12-7 Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Indiana Monitoring Sites 12-28
12-8 Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Indiana Monitoring
Sites 12-29
13-1 Geographical Information for the Kentucky Monitoring Site 13-4
13-2 Population, Motor Vehicle, and Traffic Information for the Kentucky Monitoring
Site 13-5
13-3 Average Meteorological Conditions near the Kentucky Monitoring Site 13-7
13-4 Risk-Based Screening Results for the Kentucky Monitoring Site 13-13
13-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Kentucky Monitoring Site 13-14
13-6 Risk Approximations for the Kentucky Monitoring Site 13-21
13-7 Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Kentucky Monitoring Site 13-23
13-8 Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Kentucky Monitoring
Site 13-24
14-1 Geographical Information for the Massachusetts Monitoring Site 14-4
14-2 Population, Motor Vehicle, and Traffic Information for the Massachusetts
Monitoring Site 14-5
14-3 Average Meteorological Conditions near the Massachusetts Monitoring Site 14-8
14-4 Risk-Based Screening Results for the Massachusetts Monitoring Site 14-13
14-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Massachusetts Monitoring Site 14-15
14-6 Risk Approximations for the Massachusetts Monitoring Site 14-25
14-7 Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Massachusetts Monitoring Site 14-27
14-8 Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Massachusetts
Monitoring Site 14-28
15-1 Geographical Information for the Michigan Monitoring Sites 15-6
15-2 Population, Motor Vehicle, and Traffic Information for the Michigan Monitoring
Sites 15-8
xxxvii
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LIST OF TABLES (Continued)
Page
15-3 Average Meteorological Conditions near the Michigan Monitoring Sites 15-10
15-4 Risk-Based Screening Results for the Michigan Monitoring Sites 15-20
15-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Michigan Monitoring Sites 15-22
15-6 Risk Approximations for the Michigan Monitoring Sites 15-37
15-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Michigan Monitoring Sites 15-39
15-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Michigan Monitoring
Sites 15-41
16-1 Geographical Information for the Missouri Monitoring Site 16-4
16-2 Population, Motor Vehicle, and Traffic Information for the Missouri Monitoring
Site 16-5
16-3 Average Meteorological Conditions near the Missouri Monitoring Site 16-7
16-4 Risk-Based Screening Results for the Missouri Monitoring Site 16-14
16-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Missouri Monitoring Site 16-15
16-6 Risk Approximations for the Missouri Monitoring Site 16-33
16-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Missouri Monitoring Site 16-36
16-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Missouri Monitoring
Site 16-37
17-1 Geographical Information for the New Jersey Monitoring Sites 17-9
17-2 Population, Motor Vehicle, and Traffic Information for the New Jersey Monitoring
Sites 17-12
17-3 Average Meteorological Conditions near the New Jersey Monitoring Sites 17-14
17-4 Risk-Based Screening Results for the New Jersey Monitoring Sites 17-27
17-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
New Jersey Monitoring Sites 17-31
17-6 Risk Approximations for the New Jersey Monitoring Sites 17-53
17-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the New Jersey Monitoring Sites 17-57
17-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the New Jersey Monitoring
Sites 17-59
18-1 Geographical Information for the New York Monitoring Sites 18-6
18-2 Population, Motor Vehicle, and Traffic Information for the New York Monitoring
Sites 18-8
18-3 Average Meteorological Conditions near the New York Monitoring Sites 18-10
18-4 Risk-Based Screening Results for the New York Monitoring Sites 18-19
xxxvin
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LIST OF TABLES (Continued)
Page
18-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
New York Monitoring Sites 18-21
18-6 Risk Approximations for the New York Monitoring Sites 18-26
18-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the New York Monitoring Sites 18-28
18-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the New York Monitoring
Sites 18-29
19-1 Geographical Information for the Oklahoma Monitoring Sites 19-10
19-2 Population, Motor Vehicle, and Traffic Information for the Oklahoma Monitoring
Sites 19-13
19-3 Average Meteorological Conditions near the Oklahoma Monitoring Sites 19-16
19-4 Risk-Based Screening Results for the Oklahoma Monitoring Sites 19-31
19-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Oklahoma Monitoring Sites 19-36
19-6 Risk Approximations for the Oklahoma Monitoring Sites 19-62
19-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Oklahoma Monitoring Sites 19-68
19-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Oklahoma Monitoring
Sites 19-71
20-1 Geographical Information for the Rhode Island Monitoring Site 20-4
20-2 Population, Motor Vehicle, and Traffic Information for the Rhode Island Monitoring
Site 20-6
20-3 Average Meteorological Conditions near the Rhode Island Monitoring Site 20-8
20-4 Risk-Based Screening Results for the Rhode Island Monitoring Site 20-13
20-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Rhode Island Monitoring Site 20-15
20-6 Risk Approximations for the Rhode Island Monitoring Site 20-20
20-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Rhode Island Monitoring Site 20-22
20-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Rhode Island
Monitoring Site 20-23
21-1 Geographical Information for the South Carolina Monitoring Site 21-4
21-2 Population, Motor Vehicle, and Traffic Information for the South Carolina
Monitoring Site 21-5
21-3 Average Meteorological Conditions near the South Carolina Monitoring Site 21-7
21-4 Risk-Based Screening Results for the South Carolina Monitoring Site 21-12
21-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
South Carolina Monitoring Site 21-14
21-6 Risk Approximations for the South Carolina Monitoring Site 21-19
xxxix
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LIST OF TABLES (Continued)
Page
21-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the South Carolina Monitoring Site 21-20
21-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the South Carolina
Monitoring Site 21-21
22-1 Geographical Information for the South Dakota Monitoring Sites 22-6
22-2 Population, Motor Vehicle, and Traffic Information for the South Dakota
Monitoring Sites 22-8
22-3 Average Meteorological Conditions near the South Dakota Monitoring Sites 22-10
22-4 Risk-Based Screening Results for the South Dakota Monitoring Sites 22-18
22-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
South Dakota Monitoring Sites 22-21
22-6 Risk Approximations for the South Dakota Monitoring Sites 22-28
22-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the South Dakota Monitoring Sites 22-30
22-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the South Dakota
Monitoring Sites 22-31
23-1 Geographical Information for the Texas Monitoring Sites 23-6
23-2 Population, Motor Vehicle, and Traffic Information for the Texas Monitoring Sites... 23-8
23-3 Average Meteorological Conditions near the Texas Monitoring Sites 23-10
23-4 Risk-Based Screening Results for the Texas Monitoring Sites 23-18
23-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Texas Monitoring Sites 23-20
23-6 Risk Approximations for the Texas Monitoring Sites 23-25
23-7 Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Texas Monitoring Sites 23-26
23-8 Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Texas Monitoring
Sites 23-27
24-1 Geographical Information for the Utah Monitoring Site 24-4
24-2 Population, Motor Vehicle, and Traffic Information for the Utah Monitoring Site 24-5
24-3 Average Meteorological Conditions near the Utah Monitoring Site 24-8
24-4 Risk-Based Screening Results for the Utah Monitoring Site 24-13
24-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Utah Monitoring Site 24-15
24-6 Risk Approximations for the Utah Monitoring Site 24-32
24-7 Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Utah Monitoring Site 24-35
24-8 Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Utah Monitoring
Site 24-36
xl
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LIST OF TABLES (Continued)
Page
25-1 Geographical Information for the Vermont Monitoring Sites 25-7
25-2 Population, Motor Vehicle, and Traffic Information for the Vermont
Monitoring Sites 25-9
25-3 Average Meteorological Conditions near the Vermont Monitoring Sites 25-12
25-4 Risk-Based Screening Results for the Vermont Monitoring Sites 25-22
25-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Vermont Monitoring Sites 25-25
25-6 Risk Approximations for the Vermont Monitoring Sites 25-37
25-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Vermont Monitoring Sites 25-40
25-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Vermont
Monitoring Sites 25-42
26-1 Geographical Information for the Virginia Monitoring Site 26-4
26-2 Population, Motor Vehicle, and Traffic Information for the Virginia Monitoring
Site 26-5
26-3 Average Meteorological Conditions near the Virginia Monitoring Site 26-7
26-4 Risk-Based Screening Results for the Virginia Monitoring Site 26-12
26-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Virginia Monitoring Site 26-14
26-6 Risk Approximations for the Virginia Monitoring Site 26-18
26-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Virginia Monitoring Site 26-19
26-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Virginia Monitoring
Site 26-20
27-1 Geographical Information for the Washington Monitoring Site 27-4
27-2 Population, Motor Vehicle, and Traffic Information for the Washington
Monitoring Site 27-5
27-3 Average Meteorological Conditions near the Washington Monitoring Site 27-8
27-4 Risk-Based Screening Results for the Washington Monitoring Site 27-13
27-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Washington Monitoring Site 27-15
27-6 Risk Approximations for the Washington Monitoring Site 27-32
27-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Washington Monitoring Site 27-34
27-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Washington
Monitoring Site 27-35
28-1 Geographical Information for the Wisconsin Monitoring Site 28-4
28-2 Population, Motor Vehicle, and Traffic Information for the Wisconsin
Monitoring Site 28-5
xli
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LIST OF TABLES (Continued)
Page
28-3 Average Meteorological Conditions near the Wisconsin Monitoring Site 28-8
28-4 Risk-Based Screening Results for the Wisconsin Monitoring Site 28-12
28-5 Quarterly and Annual Average Concentrations of the Pollutants of Interest for the
Wisconsin Monitoring Site 28-14
28-6 Risk Approximations for the Wisconsin Monitoring Site 28-16
28-7 Top 10 Emissions, Toxi city-Weighted Emissions, and Cancer Risk Approximations
for Pollutants with Cancer UREs for the Wisconsin Monitoring Site 28-18
28-8 Top 10 Emissions, Toxi city-Weighted Emissions, and Noncancer Hazard
Approximations for Pollutants with Noncancer RfCs for the Wisconsin
Monitoring Site 28-19
29-1 Method Precision by Analytical Method 29-4
29-2 VOC Method Precision: Coefficient of Variation Based on Duplicate and Collocated
Samples by Site 29-5
29-3 SNMOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site 29-13
29-4 Carbonyl Compound Method Precision: Coefficient of Variation Based on Duplicate
and Collocated Samples by Site 29-17
29-5 PAH Method Precision: Coefficient of Variation Based on Collocated Samples
by Site 29-20
29-6 Metals Method Precision: Coefficient of Variation Based on Collocated Samples
by Site 29-21
29-7 Hexavalent Chromium Method Precision: Coefficient of Variation Based on
Collocated Samples by Site 29-22
29-8 Analytical Precision by Analytical Method 29-23
29-9 VOC Analytical Precision: Coefficient of Variation Based on Replicate Analyses
by Site 29-25
29-10 SNMOC Analytical Precision: Coefficient of Variation Based on Replicate Analyses
by Site 29-33
29-11 Carbonyl Compound Analytical Precision: Coefficient of Variation Based on
Replicate Analyses by Site 29-37
29-12 PAH Analytical Precision: Coefficient of Variation Based on Replicate Analyses
by Site 29-40
29-13 Metals Analytical Precision: Average Coefficient of Variation Based on Replicate
Analyses by Site 29-41
29-14 Hexavalent Chromium Analytical Precision: Coefficient of Variation Based on
Replicate Analyses by Site 29-42
29-15 VOC NATTS PT Audit Samples-Percent Difference from True Value 29-43
29-16 Carbonyl Compound NATTS PT Audit Samples-Percent Difference from
True Value 29-44
29-17 PAH NATTS PT Audit Samples-Percent Difference from True Value 29-44
29-18 Metals NATTS PT Audit Samples-Percent Difference from True Value 29-44
29-19 Hexavalent Chromium PT Audit Samples-Percent Difference from True Value 29-44
xlii
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LIST OF ACRONYMS
AADT Average Annual Daily Traffic
AGL Above Ground Level
AQS Air Quality System
ASE Accelerated Solvent Extractor
ATSDR Agency for Toxic Substances and Disease Registry
CBS A Core-Based Statistical Area(s)
CFR Code of Federal Regulations
CNG Compressed Natural Gas
CSATAM Community-Scale Air Toxics Ambient Monitoring
CV Coefficient of Variation
DNPH 2,4-Dinitrophenylhydrazine
DQO Data Quality Objective(s)
EPA U.S. Environmental Protection Agency
ERG Eastern Research Group, Inc.
F Fahrenheit
FHWA Federal Highway Administration
GC/MS-FID Gas Chromatography/Mass Spectrometry and Flame lonization Detection
GHG Greenhouse Gas(es)
GIS Geographical Information System
GWP Global Warming Potential
HAP Hazardous Air Pollutant(s)
HPLC High-Performance Liquid Chromatography
HQ Hazard Quotient
HYSPLIT Hybrid Single-Particle Lagrangian Integrated Trajectory
1C Ion Chromatography
ICP-MS Inductively Coupled Plasma/Mass Spectrometry
IPCC Intergovernmental Panel on Climate Change
kt Knots
mb Millibar
MDL Method Detection Limit
mg/m3 Milligrams per cubic meter
mL Milliliter
MQO Method Quality Objective(s)
MRL Minimal Risk Level
MSA Metropolitan or Micropolitan Statistical Area(s)
MTBE Methyl tert-buty\ ether
NAAQS National Ambient Air Quality Standard
NATA National Air Toxics Assessment
xliii
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LIST OF ACRONYMS (Continued)
NATTS National Air Toxics Trends Stations
ND Non-detect
NEI National Emissions Inventory
ng/m3 Nanograms per cubic meter
NMOC Non-Methane Organic Compound(s)
NMP National Monitoring Programs
NOAA National Oceanic and Atmospheric Administration
NOx Oxides of Nitrogen
NWS National Weather Service
PAMS Photochemical Assessment Monitoring Stations
PAH Polycyclic Aromatic Hydrocarbon(s)
PM Particulate Matter
PMio Particulate Matter less than 10 microns
POM Polycyclic Organic Matter
ppbC Parts per billion carbon
ppbv Parts per billion by volume
ppm Parts per million
PT Proficiency Test
PUF Polyurethane Foam
QAPP Quality Assurance Project Plan
RfC Reference Concentration(s)
RFG Reformulated Gasoline
SATMP School Air Toxics Monitoring Program
SIM Selected Ion Monitoring
SIP State Implementation Plan(s)
SNMOC Speciated Nonmethane Organic Compound(s)
UATMP Urban Air Toxics Monitoring Program
VOC Volatile Organic Compound(s)
TAD Technical Assistance Document
TNMOC Total Nonmethane Organic Compound(s)
tpy Tons per year
TRI Toxics Release Inventory
TSP Total Suspended Particulate
TSV Total Spatial Variance
|ig/m3 Micrograms per cubic meter
jiL Microliter
URE Unit Risk Estimate(s)
VMT Vehicle Miles Traveled
WBAN Weather Bureau/Army/Navy ID
xliv
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Abstract
This report presents the results and conclusions from the ambient air monitoring conducted
as part of the 2011 National Monitoring Programs (NATTS, UATMP, and CSATAM) - three
individual programs with different goals, but together result in a better understanding and
appreciation of the nature and extent of toxic air pollution. The 2011 NMP includes data from
samples collected at 51 monitoring sites that collected 24-hour air samples, typically on a l-in-6
or l-in-12 day schedule. Twenty-four sites sampled for 61 volatile organic compounds (VOC); 31
sites sampled for 14 carbonyl compounds; eight sites sampled for 80 speciated nonmethane
organic compounds (SNMOC); 23 sites sampled for 22 polycyclic aromatic hydrocarbons (PAH);
15 sites sampled for 11 metals; and 22 sites sampled for hexavalent chromium. Over 218,900
ambient air concentrations were measured during the 2011 NMP. This report uses various
graphical, numerical, and statistical analyses to put the vast amount of ambient air monitoring
data collected into perspective. Not surprisingly, the ambient air concentrations measured during
the program varied significantly from city-to-city and from season-to-season.
The ambient air monitoring data collected during the 2011 NMP serve a wide range of
purposes. Not only do these data characterize the nature and extent of air pollution close to the
51 individual monitoring sites participating in these programs, but they also identify trends and
patterns that may be common to both urban and rural environments, and across the country.
Therefore, this report presents results that are specific to particular monitoring locations and
presents other results that are common to all environments. The results presented provide
additional insight into the complex nature of air pollution. The raw data are included in the
appendices of this report.
xlv
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1.0 Introduction
Air pollution contains many components that originate from a wide range of stationary,
mobile, and natural emissions sources. Because some of these components include air toxics that
are known or suspected to have the potential for negative human health impacts, the
U.S. Environmental Protection Agency (EPA) encourages state, local, and tribal agencies to
understand and appreciate the nature and extent of toxic air pollution in their respective
locations. To achieve this goal, EPA sponsors the National Monitoring Programs (NMP), which
include the Photochemical Assessment Monitoring Stations (PAMS) network, Urban Air Toxics
Monitoring Program (UATMP), National Air Toxics Trends Stations (NATTS) network,
Community-Scale Air Toxics Ambient Monitoring (CSATAM) Program, and monitoring for
other pollutants such as Non-Methane Organic Compounds (NMOCs). This report focuses on the
UATMP, NATTS, and CSATAM programs. These programs have the following program-
specific objectives:
The primary objective of the UATMP is to characterize the composition and
magnitude of air toxics pollution through ambient air monitoring.
The primary objective of the NATTS network is to obtain a statistically significant
quantity of high-quality representative air toxics measurements such that long-term
trends can be identified.
The primary objective of the CSATAM Program is to conduct local-scale
investigative air toxics monitoring projects.
1.1 Background
EPA began the NMOC program in 1984. Monitoring for selected NMOCs was performed
during the morning hours of the summer ozone season. NMOC data were to be used to better
understand ozone formation and to develop ozone control strategies. The UATMP was initiated
by EPA in 1988 as an extension of the existing NMOC program to meet the increasing need for
information on air toxics. Over the years, the program has grown in both participation and
targeted pollutants (EPA, 2009a). The program has allowed for the identification of compounds
that are prevalent in ambient air and for participating agencies to screen air samples for
concentrations of air toxics that could potentially result in adverse human health effects.
The NATTS network was created to generate long-term ambient air toxics concentration
data at specific fixed sites across the country. The 10-City Pilot program (LADCO, 2003) was
developed and implemented during 2001 and 2002, leading to the development and initial
1-1
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implementation of the NATTS network during 2003 and 2004. The goal of the program is to
estimate the concentrations of air toxics on a national level at fixed sites that remain active over
an extended period of time (EPA, 2009a). The generation of large quantities of high-quality data
over an extended period may allow concentration trends (i.e., any substantial increase or
decrease over a period of time) to be identified. The data generated are also used for validating
modeling results and emissions inventories, assessing current regulatory benchmarks, and
assessing the potential for developing cancerous and noncancerous health effects (EPA, 2012a).
The initial site locations were based on results from preliminary air toxics pilot programs such as
the 1996 National Air Toxics Assessment (NATA), which used air toxics emissions data to
model ambient monitoring concentrations across the nation. Monitoring sites were placed in both
urban and rural locations. Urban areas were chosen to measure population exposure, while rural
areas were chosen to determine background levels of air pollution (EPA, 2009b). Currently, 27
NATTS sites are strategically placed across the country (EPA, 2012b).
The CSATAM Program was initiated in 2004 and is intended to support state, local, and
tribal agencies in conducting discreet, investigative projects of approximately 2-year durations
via periodic grant competitions (EPA, 2009a). The objectives of the CSATAM Program include
identifying and profiling air toxics sources; developing and assessing emerging measurement
methods; characterizing the degree and extent of local air toxics problems; and tracking progress
of air toxics reduction activities (EPA, 2009a).
Many environmental and health agencies have participated in these programs to assess
the sources, effects, and changes in air pollution within their jurisdictions. In past reports,
measurements from UATMP, NATTS, and CSATAM monitoring sites have been presented
together and referred to as "UATMP sites." In more recent reports, a distinction is made among
the three programs due to the increasing number of sites covered under each program. Thus, it is
appropriate to describe each program; to distinguish among their purposes and scopes; and to
integrate the data, which allows each program's objectives and goals to complement each other.
1.2 The Report
This report summarizes and interprets the 2011 UATMP, NATTS, and CSATAM
monitoring efforts of the NMP. Included in this report are data collected at the 51 monitoring
1-2
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sites around the country whose operating agencies have opted to have their samples analyzed by
EPA's national contract laboratory, Eastern Research Group, Inc. (ERG). Agencies operating
sites under the NMP are not required to have their samples analyzed by ERG or may not have
samples for all methods analyzed by ERG, as they may have their own laboratories or use other
contract laboratories. In these cases, data are generated by sources other than ERG and are not
included in this report. The 51 sites included in this report are located in or near 33 urban or rural
locations in 23 states and the District of Columbia, including 29 metropolitan or micropolitan
statistical areas (MSAs).
This report provides both a qualitative overview of air toxics pollution at selected urban
and rural locations and a quantitative data analysis of the factors that appear to affect the
behavior of air toxics in urban and rural areas most significantly. This report also focuses on data
characterizations for each of the 51 different air sampling locations, a site-specific approach that
allows for a much more detailed evaluation of the factors (e.g., emissions sources, natural
sources, meteorological influences) that affect air quality differently from one location to the
next. Much of the data analysis and interpretation contained in this report focuses on pollutant-
specific risk potential.
This report offers participating agencies relevant information and insight into important
air quality issues. For example, participating agencies can use trends and patterns in the
monitoring data to determine whether levels of air pollution present public health concerns, to
identify which emissions sources contribute most to air pollution, or to forecast whether
proposed pollution control initiatives could significantly improve air quality. Monitoring data
may also be compared to modeling results, such as from EPA's NATA.
Policy-relevant questions that the monitoring data may help answer include the
following:
Which anthropogenic sources substantially affect air quality?
Have pollutant concentrations decreased as a result of regulations (or increased
despite regulation)?
Which pollutants contribute the greatest health risk on a short-term, intermediate-
term, and long-term basis?
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The data analyses contained in this report are applied to each participating UATMP,
NATTS, or C SAT AM monitoring site, depending upon pollutants sampled and duration of
sampling. Although many types of analyses are presented, state and local environmental
agencies are encouraged to perform additional evaluations of the monitoring data so that the
many factors that affect their specific ambient air quality can be understood fully.
To facilitate examination of the 2011 UATMP, NATTS, and CSATAM monitoring data,
henceforth referred to as NMP data, the complete set of measured concentrations is presented in
the appendices of this report. In addition, these data are publicly available in electronic format
from EPA's Air Quality System (AQS) (EPA, 2012c).
This report is organized into 31 sections and 17 appendices. While each state section is
designed to be a stand-alone section to allow those interested in a particular site or state to
understand the associated data analyses without having to read the entire report, it is
recommended that Sections 1 through 4 (Introduction, Monitoring Programs Network Overview,
Data Treatments and Methods, and Summary of Results) and Sections 29 and 30 (Data Quality
and Results, Conclusions, and Recommendations) be read as complements to the individual state
sections. Table 1-1 highlights the contents of each section.
Table 1-1. Organization of the 2011 National Monitoring Programs Report
Report
Section
Section Title
Overview of Contents
Introduction
This section serves as an introduction to the
background and scope of the NMP (specifically, the
UATMP, NATTS, and CSATAM).
The 2011 National Monitoring
Programs Network
This section provides information on the 2011 NMP
and network:
Monitoring locations
Pollutants selected for monitoring
Sampling and analytical methods
Sampling schedules
Completeness of the air monitoring programs.
Summary of the 2011 National
Monitoring Programs Data
Treatments and Methods
This section presents and discusses the data treatments
used on the 2011 NMP data to determine significant
trends and relationships in the data, characterize data
based on how ambient air concentrations varied with
monitoring location and with time, interpret the
significance of the observed spatial and temporal
variations, and evaluate risk.
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Table 1-1. Organization of the 2011 National Monitoring Programs Report (Continued)
Report
Section
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Section Title
Summary of the 201 1 National
Monitoring Programs Data
Sites in Arizona
Sites in California
Sites in Colorado
Site in the District of Columbia
Sites in Florida
Site in Georgia
Sites in Illinois
Sites in Indiana
Site in Kentucky
Site in Massachusetts
Sites in Michigan
Site in Missouri
Sites in New Jersey
Sites in New York
Sites in Oklahoma
Overview of Contents
This section presents and discusses the results of the
data treatments from the 201 1 NMP data.
Monitoring results for the sites in the Phoenix-Mesa-
Glendale, AZ MSA (PXSS and SPAZ)
Monitoring results for the sites in the Los Angeles-
Long Beach-Santa Ana, CA MSA (CELA), the
Riverside-San Bernardino-Ontario, CA MSA (RUCA),
and the San Jose-Sunnyvale-Santa Clara, CA MSA
(SJJCA)
Monitoring results for the sites in the Grand Junction,
CO MSA (GPCO) and Garfield County (BMCO,
BRCO, PACO, and RICO)
Monitoring results for the site in the Washington-
Arlington-Alexandria, DC-VA-MD-WV MSA
(WADC)
Monitoring results for the sites in the Orlando-
Kissimmee-Sanford, FL MSA (ORFL and PAFL) and
the Tampa-St. Petersburg-Clearwater, FL MSA
(AZFL, SKFL, and SYFL)
Monitoring results for the site in the Atlanta-Sandy
Springs-Marietta, GA MSA (SDGA)
Monitoring results for the sites in the Chicago- Joliet-
Naperville, IL-IN-WI MSA (NBIL and SPIL)
Monitoring results for the sites in the Chicago-Joliet-
Naperville, IL-IN-WI MSA (INDEM) and the
Indianapolis-Carmel, IN MSA (WPIN)
Monitoring results for the site in Gray son, KY
(GLKY)
Monitoring results for the site in the Boston-
Cambridge-Quincy, MA-NH MSA (BOMA)
Monitoring results for the sites in the Detroit- Warren-
Livonia, MI MSA (DEMI, RRMI, and SWMI)
Monitoring results for the site in the St. Louis, MO-IL
MSA (S4MO)
Monitoring results for the sites in the New York-
Northern New Jersey-Long Island, NY-NJ-PA MSA
(CHNJ, ELNJ, NBNJ, and PANJ)
Monitoring results for the site in the New York-
Northern New Jersey-Long Island, NY-NJ-PA MSA
(MONY) and the Rochester, NY MSA (ROCH)
Monitoring results for the sites in the Tulsa, OK MSA
(TOOK and TMOK), the Oklahoma City, OK MSA
(MWOK and OCOK), and Pryor Creek, OK (PROK)
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Table 1-1. Organization of the 2011 National Monitoring Programs Report (Continued)
Report
Section
20
21
22
23
24
25
26
27
28
29
30
31
Section Title
Site in Rhode Island
Site in South Carolina
Sites in South Dakota
Sites in Texas
Site in Utah
Sites in Vermont
Site in Virginia
Site in Washington
Site in Wisconsin
Data Quality
Results, Conclusions, and
Recommendations
References
Overview of Contents
Monitoring results for the site in the Providence-New
Bedford-Fall River, RI-MA MSA (PRRI)
Monitoring results for the site in Chesterfield, SC
(CHSC)
Monitoring results for the sites in the Sioux City, IA-
NE-SD MSA (UCSD) and the Sioux Falls, SD MSA
(SSSD)
Monitoring results for the sites in the Houston-Sugar
Land-Baytown, TX MSA (CAMS 35) and the
Marshall, TX MSA (CAMS 85)
Monitoring results for the site in the Ogden-Clearfield,
UT MSA (BTUT)
Monitoring results for the sites in the Burlington-South
Burlington, VT MSA (BURVT and UNVT) and the
Rutland, VT MSA (RUVT)
Monitoring results for the site in the Richmond, VA
MSA (RIVA)
Monitoring results for the site in the Seattle-Tacoma-
Bellevue, WA MSA (SEWA)
Monitoring results for the site in the Beaver Dam, WI
MSA (HOWI)
This section defines and discusses the concepts of
precision and accuracy. Based on quantitative and
qualitative analyses, this section comments on the
precision and accuracy of the 201 1 NMP ambient air
monitoring data.
This section summarizes the most significant findings
of the report and makes several recommendations for
future projects that involve ambient air monitoring.
This section lists the references cited throughout the
report.
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2.0 The 2011 National Monitoring Programs Network
Agencies operating UATMP, NATTS, or CSATAM sites may choose to have their
samples analyzed by EPA's contract laboratory, ERG, in Morrisville, NC. Data from 51
monitoring sites that collected 24-hour integrated ambient air samples for up to 12 months, at
l-in-6 or l-in-12 day sampling intervals, and sent them to ERG for analysis are included in this
report. Samples were analyzed for concentrations of selected hydrocarbons, halogenated
hydrocarbons, and polar compounds from canister samples (Speciated Nonmethane Organic
Compounds (SNMOCs) and/or Method TO-15),
carbonyl compounds from sorbent cartridge samples
(Method TO-11A), polycyclic aromatic hydrocarbons
(PAHs) from polyurethane foam (PUF) and XAD-2ฎ
resin samples (Method TO-13 A), trace metals from
filters (Method IO-3.5), and hexavalent chromium from
sodium bicarbonate-coated filters (EPA-approved
method). Section 2.2 provides further details on each of
the sampling methodologies used to collect and analyze
samples.
Agencies operating these sites are
not required to have their samples
analyzed by ERG. They may have
samples for only select methods
analyzed by ERG, as they may
have their own laboratories. In
these cases, data are generated by
sources other than ERG and are
not included in this report.
The following sections review the monitoring locations, pollutants selected for
monitoring, sampling and analytical methods, collection schedules, and completeness of the
2011NMPdataset.
2.1 Monitoring Locations
For the NATTS network, monitor siting is based on the need to assess population
exposure and background-level concentrations. For the UATMP and CSATAM programs,
representatives from the state, local, and tribal agencies that voluntarily participate in the
programs select the monitoring locations based on specific siting criteria and study needs.
Among these programs, monitors were placed in urban areas near the centers of heavily
populated cities (e.g., Chicago, IL and Phoenix, AZ), while others were placed in moderately
populated rural areas (e.g., Horicon, WI and Chesterfield, SC). Figure 2-1 shows the locations of
the 51 monitoring sites participating in the 2011 programs, which encompass 33 different urban
and rural areas. Outlined in Figure 2-1 are the associated core-based statistical areas (CBSA), as
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designated by the U.S. Census Bureau, where each site is located (Census Bureau, 2010). A
CBS A refers to either a metropolitan (an urban area with 50,000 or more people) or micropolitan
(an urban area with at least 10,000 people but less than 50,000 people) statistical area (Census
Bureau, 2012a).
Table 2-1 lists the respective monitoring program and the years of program participation
for the 51 monitoring sites. All 51 monitoring sites have been included in previous annual
reports, although two sites began sampling again under the NMP in 2011 after nine years. These
two sites are highlighted in Table 2-1.
As Figure 2-1 and Table 2-1 show, the 2011 NMP sites are widely distributed across the
country. Detailed information about the monitoring sites is provided in Table 2-2 and
Appendix A. Monitoring sites that are designated as part of the NATTS network are indicated by
bold italic type in Table 2-1 and subsequent tables throughout this report in order to distinguish
this program from the other two programs. Table 2-2 shows that the locations of the monitoring
sites vary significantly from site to site. These sites are located in areas of differing elevation,
population, land use, climatology, and topography. A more detailed look at each monitoring
site's surroundings is provided in the individual state sections.
For record-keeping and reporting purposes, each site was assigned the following:
A unique four- or five-letter site code used to track samples from the monitoring site
to the ERG laboratory.
A unique nine-digit AQS site code used to index monitoring results in the AQS
database.
This report cites the four- or five-letter site code when presenting selected monitoring
results. For reference, each site's AQS site code is provided in Table 2-2.
2-2
-------
Figure 2-1. Locations of the 2011 National Monitoring Programs Monitoring Sites
Underbill,
A^
Rutland, VT
Rochester, NY \ LJ^Boston, MA
Horicon.W."' ' '~ ' '
, Q I \ Dearborn, Ml
V, _ .^Detroit, MIV|E^ v^-Paterson, NJ
North brook, It-rrHgl/Riyer Rouge, Ml Chester, NJ
Schiller Park, lirฃ-fGary, i_N
Indianapolis, IN
Sioux Falls, SD
Union CountyTSD
Providence, Rl
New York, NY
Elizabeth, NJ
New Brunswick, NJ
San Jose, CA / Parachute, CO Rif|e co
Battlement Mesa, CO silt, CO
Washington,-DC
Grand Junction, CO
P/yor Creek, OK
OK
Oklahoma City, OK
Chesterfield, SC
Karnack, TX
Deer Park, TX
Winter Park, FL
Orlando, FL
Pinellas Park, FL
St. Petersburg, FL
Legend
Program
CSATAM
o NATTS
UATMP
Metropolitan/Micropolitan Statistical Area
-------
Table 2-1. 2011 National Monitoring Programs Sites and Past Program Participation
Monitoring Location
and Site
Battlement Mesa, CO (BMCO)
Boston, MA (BOMA)
Bountiful, UT (BTUT)
Burlington, VT (BURVT)
Chester, NJ (CHNJ)
Chesterfield, SC (CHSC)
Dearborn, MI (DEMI)
Decatur, GA (SDGA)
Deer Park, TX (CAMS 35)
Detroit, MI (SWMI)
Elizabeth, NJ (ELNJ)
Gary, IN (INDEM)
Grand Junction, CO (GPCO)
Grayson, KY (GLKY)
Horicon, WI (HOW)
Indianapolis, IN (WPIN)
Karnack, TX (CAMS 85)
Program
UATMP
NATTS
NATTS
UATMP
UATMP
NATTS
NATTS
NATTS
NATTS
UATMP
UATMP
UATMP
NATTS
NATTS
NATTS
UATMP
NATTS
2001 and Earlier
2001
2001
2001
1999-2001
2002
-------
Table 2-1. 2011 National Monitoring Programs Sites and Past Program Participation (Continued)
Monitoring Location
and Site
Los Angeles, CA (CELA)
Midwest City, OK (MWOK)
New Brunswick, NJ (NBNJ)
New York, NY (MONY)
Northbrook, IL (NBIL)
Oklahoma City, OK (OCOK)
Orlando, FL (PAFL)
Parachute, CO (PACO)
Paterson, NJ (PANJ)
Phoenix, AZ (PXSS)
Phoenix, AZ (SPAZ)
Pinellas Park, FL (SKFL)
Plant City, FL (SYFL)
Providence, RI (PRRI)
Pryor Creek, OK (PROK)
Richmond, VA (RIVA)
Rifle, CO (RICO)
Program
NATTS
UATMP
UATMP
NATTS
NATTS
UATMP
UATMP
UATMP
CSATAM
NATTS
UATMP
NATTS
NATTS
NATTS
UATMP
NATTS
UATMP
2001 and Earlier
2001
2001
2001
2002
/
/
2003
/
-------
Table 2-1. 2011 National Monitoring Programs Sites and Past Program Participation (Continued)
Monitoring Location
and Site
River Rouge, MI (RRMI)
Rochester, NY (ROCH)
Rubidoux, CA (RUCA)
Rutland, VT (RUVT)
San Jose, CA (SJJCA)
Schiller Park, IL (SPIL)
Seattle, WA (SEW A)
Silt, CO (BRCO)
Sioux Falls, SD (SSSD)
St. Louis, MO (S4MO)
St. Petersburg, FL (AZFL)
Tulsa, OK (TMOK)
Tulsa, OK (TOOK)
Underbill, VT (UNVT)
Union County, SD (UCSD)
Washington, D.C. (WADC)
Winter Park, FL (ORFL)
Program
UATMP
NATTS
NATTS
UATMP
NATTS
UATMP
NATTS
UATMP
UATMP
NATTS
UATMP
UATMP
UATMP
NATTS
UATMP
NATTS
UATMP
2001 and Earlier
2001
1995-1999
1991-1992, 2001
1990-1991
2002
S
/
/
/
2003
/
/
/
-------
Table 2-2. Site Characterizing Information for the 2011 National Monitoring Programs Sites
Site
Code
AZFL
BMCO
BOMA
BRCO
BTUT
BURVT
CAMS 35
CAMS 85
CELA
CHNJ
CHSC
DEMI
AQS
Code
12-103-0018
NA
25-025-0042
08-045-0009
49-011-0004
50-007-0014
48-201-1039
48-203-0002
06-037-1103
34-027-3001
45-025-0001
26-163-0033
Location
St. Petersburg, FL
Battlement Mesa, CO
Boston, MA
Silt, CO
Bountiful, UT
Burlington, VT
Deer Park, TX
Karnack TX
Los Angeles, CA
Chester NT
Chesterfield SC
Dearborn, MI
Land Use
Residential
Residential
Commercial
Agricultural
Residential
Commercial
Residential
Agricultural
Residential
Agricultural
Forest
Industrial
Location
Setting
Suburban
Rural
Urban/City
Center
Rural
Suburban
Urban/City
Center
Suburban
Rural
Urban/City
Center
Rural
Rural
Suburban
County-level
Population"
917,398
56,270
730,932
56,270
311,811
157,491
4,180,894
66,296
9,889,056
494,976
46,557
1,802,096
County-level
Vehicle
Registration,
# of Vehicles'1
(Year)
877,075
(2011)
72,957
(2010)
481,199
(2011)
72,957
(2010)
239,582
(2011)
169,767
(2012)
3,164,173
(2011)
70,858
fioin
7,360,573
(2011)
389,359
(2010)d
40,492
(2011)
1,334,752
(2011)
Estimated
Daily Traffic,
AADTb
(Year)
40,500
(2011)
2,527
(2002)
31,400
(2007)
150
(2002)
113,955
(2010)
14,000
(2007)
31,043
(2004)
1,250
(2010)
230,000
(2011)
12,917
(2010)
550
(2011)
92,800
(2011)
County-level
Stationary
Source HAP
Emissions
from the 2008
NEIC
(tpy)
1,381.26
1,364.26
572.38
1,364.26
391.90
347.53
9,322.29
593.11
14,794.19
198.46
97.19
7,384.27
County-level
Mobile Source
HAP
Emissions
from the 2008
NEIC
(tpy)
3,808.72
353.08
1,156.01
353.08
1,198.09
623.35
11,313.66
413.72
14,628.66
1,907.47
209.23
7,014.06
to
BOLD ITALICS = EPA-designaled NATTS site
""Reference: Census Bureau, 2012b
blndividual references provided in each state section.
c Reference: EPA, 2012d
dThe proportion of county-level population to the state-level population was applied to state-level vehicle registration figure and used as a surrogate when county-
level vehicle registration counts were not available.
eGPCO's hexavalent chromium monitor is at a separate, but adjacent, location; thus, this site has two AQS codes.
NA = Data not loaded into AQS per agency request
-------
Table 2-2. Site Characterizing Information for the 2011 National Monitoring Programs Sites (Continued)
Site
Code
ELNJ
GLKY
GPCOe
HOW
INDEM
MONY
MWOK
NBIL
NBNJ
OCOK
ORFL
PACO
AQS
Code
34-039-0004
21-043-0500
08-077-0017
08-077-0018
55-027-0001
18-089-0022
36-005-0080
40-109-0041
17-031-4201
34-023-0006
40-109-1037
12-095-2002
08-045-0005
Location
Elizabeth, NJ
Grayson, KY
Grand Junction, CO
Horicon, WI
Gary, IN
New York, NY
Midwest City, OK
Northbrook, IL
New Brunswick NT
Oklahoma City, OK
Winter Park, FL
Parachute, CO
Land Use
Industrial
Residential
Commercial
Agricultural
Industrial
Residential
Commercial
Residential
Agricultural
Residential
Commercial
Residential
Location
Setting
Suburban
Rural
Urban/City
Center
Rural
Urban/City
Center
Urban/City
Center
Urban/City
Center
Suburban
Rural
Suburban
Urban/City
Center
Urban/City
Center
County-level
Population"
539,494
27,586
147,083
88,661
495,558
1,392,002
732,371
5,217,080
814,217
732,371
1,169,107
56,270
County-level
Vehicle
Registration,
# of Vehicles'1
(Year)
424,894
(2010)d
32,398
(2011)
178,425
(2010)
100,176
(2011)
419,431
(2011)
246,748
(2011)
832,160
(2011)
2,072,399
(2011)
640,893
(2010)d
832,160
(2011)
1,056,627
(2011)
72,957
(2010)
Estimated
Daily Traffic,
AADTb
(Year)
250,000
(2006)
428
(2009)
11,000
(2011)
5,000
(2008)
34,240
(2010)
91,465
(2010)
40,900
(2011)
34,600
(2011)
114,322
(2010)
40,900
(2011)
32,500
(2011)
16,000
(2011)
County-level
Stationary
Source HAP
Emissions
from the 2008
NEIC
(tpy)
360.61
55.08
532.80
531.88
1,486.55
2,171.17
1,242.77
15,376.26
475.76
1,242.77
1,791.25
1,364.26
County-level
Mobile Source
HAP
Emissions
from the 2008
NEIC
(tpy)
1,342.05
179.45
573.11
467.91
1,857.03
1,217.06
3,717.21
11,796.13
2,290.35
3,717.21
4,785.53
353.08
to
oo
BOLD ITALICS = EPA-designaled NATTS site
""Reference: Census Bureau, 2012b
blndividual references provided in each state section.
c Reference: EPA, 2012d
dThe proportion of county-level population to the state-level population was applied to state-level vehicle registration figure and used as a surrogate when county-
level vehicle registration counts were not available.
eGPCO's hexavalent chromium monitor is at a separate, but adjacent, location; thus, this site has two AQS codes.
NA = Data not loaded into AQS per agency request
-------
Table 2-2. Site Characterizing Information for the 2011 National Monitoring Programs Sites (Continued)
Site
Code
PAFL
PANJ
PROK
PRRI
PXSS
RICO
RIVA
ROCH
RRMI
RUCA
RUVT
S4MO
AQS
Code
12-095-1004
34-031-0005
40-097-0187
44-007-0022
04-013-9997
08-045-0007
51-087-0014
36-055-1007
26-163-0005
06-065-8001
50-021-0002
29-510-0085
Location
Orlando, FL
Paterson, NJ
Pryor Creek, OK
Providence, RI
Phoenix, AZ
Rifle, CO
Richmond, VA
Rochester, NY
River Rouge, MI
Rubidoux, CA
Rutland, VT
St. Louis, MO
Land Use
Commercial
Commercial
Industrial
Residential
Residential
Commercial
Residential
Residential
Industrial
Residential
Commercial
Residential
Location
Setting
Suburban
Urban/City
Center
Suburban
Urban/City
Center
Urban/City
Center
Urban/City
Center
Suburban
Urban/City
Center
Suburban
Suburban
Urban/City
Center
Urban/City
Center
County-level
Population"
1,169,107
502,007
41,389
626,709
3,880,244
56,270
310,445
745,625
1,802,096
2,239,620
61,289
1,316,761
County-level
Vehicle
Registration,
# of Vehicles'1
(Year)
1,056,627
(2011)
396,602
(2010)d
39,968
(2011)
485,837
(2010)d
3,776,819
(2011)
72,957
(2010)
354,721
(2011)
550,992
(2011)
1,334,752
(2011)
1,711,492
(2011)
70,900
(2012)
1,114,812
(2011)
Estimated
Daily Traffic,
AADTb
(Year)
46,000
(2011)
22,272
(2010)
15,100
(2011)
136,800
(2009)
184,000
(2010)
17,000
(2011)
73,000
(2011)
86,198
(2010)
98,500
(2011)
145,000
(2011)
7,200
(2010)
79,558
(2011)
County-level
Stationary
Source HAP
Emissions
from the 2008
NEIC
(tpy)
1,791.25
162.17
329.16
906.46
1,618.22
1,364.26
740.28
1,809.55
7,384.27
2,552.70
135.82
1,054.65
County-level
Mobile Source
HAP
Emissions
from the 2008
NEIC
(tpy)
4,785.53
1,064.24
256.05
1,485.96
11,681.75
353.08
1,020.76
2,250.12
7,014.06
3,490.17
308.74
1,157.32
to
BOLD ITALICS = EPA-designaled NATTS site
""Reference: Census Bureau, 2012b
blndividual references provided in each state section.
c Reference: EPA, 2012d
dThe proportion of county-level population to the state-level population was applied to state-level vehicle registration figure and used as a surrogate when county-
level vehicle registration counts were not available.
eGPCO's hexavalent chromium monitor is at a separate, but adjacent, location; thus, this site has two AQS codes.
NA = Data not loaded into AQS per agency request
-------
Table 2-2. Site Characterizing Information for the 2011 National Monitoring Programs Sites (Continued)
Site
Code
SDGA
SEWA
SJJCA
SKFL
SPAZ
SPIL
SSSD
SWMI
SYFL
TMOK
TOOK
UCSD
AQS
Code
13-089-0002
53-033-0080
06-085-0005
12-103-0026
04-013-4003
17-031-3103
46-099-0008
26-163-0015
12-057-3002
40-143-1127
40-143-0235
46-127-0001
Location
Decatur, GA
Seattle, WA
San Jose, CA
Pinellas Park, FL
Phoenix, AZ
Schiller Park, IL
Sioux Falls, SD
Detroit, MI
Plant City, FL
Tulsa, OK
Tulsa, OK
TTninn County SD
Land Use
Residential
Industrial
Commercial
Residential
Residential
Mobile
Commercial
Commercial
Residential
Residential
Industrial
Agricultural
Location
Setting
Suburban
Suburban
Urban/City
Center
Suburban
Urban/City
Center
Suburban
Urban/City
Center
Urban/City
Center
Rural
Urban/City
Center
Urban/City
Center
Rural
County-level
Population"
699,893
1,969,722
1,809,378
917,398
3,880,244
5,217,080
171,752
1,802,096
1,267,775
610,599
610,599
14,651
County-level
Vehicle
Registration,
# of Vehicles'1
(Year)
472,535
(2011)
1,783,335
(2011)
1,517,190
(2011)
877,075
(2011)
3,776,819
(2011)
2,072,399
(2011)
210,914
(2011)
1,334,752
(2011)
1,135,945
(2011)
603,926
(2011)
603,926
(2011)
25,419
(2011)
Estimated
Daily Traffic,
AADTb
(Year)
140,820
(2011)
226,000
(2011)
104,000
(2011)
47,000
(2011)
128,000
(2010)
190,000
(2010)
18,700
(2011)
93,000
(2011)
10,600
(2011)
12,600
(2011)
63,000
(2011)
156
(2007)
County-level
Stationary
Source HAP
Emissions
from the 2008
NEIC
(tpy)
779.22
3,191.49
3,325.51
1,381.26
1,618.22
15,376.26
382.22
7,384.27
2,633.02
1,219.02
1,219.02
62.28
County-level
Mobile Source
HAP
Emissions
from the 2008
NEIC
(tpy)
3,044.68
9,694.40
2,772.68
3,808.72
11,681.75
11,796.13
600.33
7,014.06
4,579.82
3,065.07
3,065.07
122.79
BOLD ITALICS = EPA-designaled NATTS site
""Reference: Census Bureau, 2012b
blndividual references provided in each state section.
c Reference: EPA, 2012d
dThe proportion of county-level population to the state-level population was applied to state-level vehicle registration figure and used as a surrogate when county-
level vehicle registration counts were not available.
eGPCO's hexavalent chromium monitor is at a separate, but adjacent, location; thus, this site has two AQS codes.
NA = Data not loaded into AQS per agency request
-------
Table 2-2. Site Characterizing Information for the 2011 National Monitoring Programs Sites (Continued)
Site
Code
UNVT
WADC
WPIN
AQS
Code
50-007-0007
11-001-0043
18-097-0078
Location
Underbill, VT
Washington, D.C.
Indianapolis, IN
Land Use
Forest
Commercial
Residential
Location
Setting
Rural
Urban/City
Center
Suburban
County-level
Population"
157,491
617,996
911,296
County-level
Vehicle
Registration,
# of Vehicles'1
(Year)
169,767
(2012)
213,232
(2010)
820,767
(2011)
Estimated
Daily Traffic,
AADTb
(Year)
1,100
(2011)
7,700
(2009)
143,970
(2010)
County-level
Stationary
Source HAP
Emissions
from the 2008
NEIC
(tpy)
347.53
632.23
2,965.43
County-level
Mobile Source
HAP
Emissions
from the 2008
NEIC
(tpy)
623.35
1,257.69
3,380.45
BOLD ITALICS = EPA-designated NATTS site
""Reference: Census Bureau, 2012b
blndividual references provided in each state section.
c Reference: EPA, 2012d
dThe proportion of county-level population to the state-level population was applied to state-level vehicle registration figure and used as a surrogate when county-
level vehicle registration counts were not available.
eGPCO's hexavalent chromium monitor is at a separate, but adjacent, location; thus, this site has two AQS codes.
NA = Data not loaded into AQS per agency request
-------
The proximity of the monitoring sites to different emissions sources, especially industrial
facilities and heavily traveled roadways, often explains the observed spatial variations in ambient
air quality. To provide a first approximation of the potential contributions of stationary and
mobile source emissions on ambient air quality at each site, Table 2-2 also lists the following:
The number of people living within each monitoring site's respective county.
The county-level number of motor vehicles registered in each site's respective
county, based on total vehicle registrations.
The number of vehicles passing the nearest available roadway to the monitoring site,
generally expressed as average annual daily traffic (AADT).
Stationary and mobile source HAP emissions for the monitoring site's residing
county, according to the 2008 National Emissions Inventory (NEI).
This information is discussed in further detail in the individual state sections.
2.2 Analytical Methods and Pollutants Targeted for Monitoring
Air pollution typically contains hundreds of components, including, but not limited to,
volatile organic compounds (VOCs), metals, and paniculate matter (PM). Because the sampling
and analysis required to monitor for every component of air pollution has been prohibitively
expensive, the NMP focuses on specific pollutants that are analyzed using specific methods, as
listed below. The target pollutants varied significantly from monitoring site to monitoring site.
Compendium Method TO-15 was used to measure ambient air concentrations of
61 VOCs.
EPA-approved SNMOC Method was used to measure 80 ozone precursors. This
method was often performed concurrently with Method TO-15.
Compendium Method TO-11A was used to measure ambient air concentrations of
14 carbonyl compounds.
Compendium Method TO-13A was used to measure ambient air concentrations of
22 PAHs.
Compendium MethodIO-3.5 was used to measure ambient air concentrations of
11 metals.
EPA-approved hexavalent chromium method was used to measure ambient air
concentrations of hexavalent chromium.
2-12
-------
At each monitoring site, the sample collection equipment was installed either as a stand-
alone sampler or in a temperature-controlled enclosure (usually a trailer or a shed) with the
sampling probe inlet exposed to the ambient air. With these common setups, most monitoring
sites sampled ambient air at heights approximately 5 to 20 feet above local ground level.
The detection limits of the analytical methods must be considered carefully when
interpreting the corresponding ambient air monitoring data. By definition, method detection
limits (MDLs) represent the lowest concentrations at which laboratory equipment have been
experimentally determined to reliably quantify concentrations of selected pollutants to a specific
confidence level. If a pollutant's concentration in ambient air is below the method sensitivity (as
gauged by the MDL), the analytical method might not differentiate the pollutant from other
pollutants in the sample or from the random "noise" inherent in the analyses. While
quantification below the MDL is possible, the measurement reliability is lower. Therefore, when
pollutants are present at concentrations below their respective detection limits, multiple analyses
of the same sample may lead to a wide range of measurement results, including highly variable
concentrations or "non-detect" observations (i.e., the pollutant was not detected by the
instrument). Data analysts should exercise caution when interpreting monitoring data with a high
percentage of reported concentrations at levels near or below the corresponding detection limits.
MDLs are determined annually at the ERG laboratory using 40 CFR, Part 136
Appendix B procedures (EPA, 2012e) in accordance with the specifications presented in the
NATTS Technical Assistance Document (TAD) (EPA, 2009b). This procedure involves
analyzing at least seven replicate standards prepared on/in the appropriate sampling media (per
analytical method). Instrument-specific detection limits (replicate analysis of standards only) are
not determined because sample contamination and preparation variability would not be
considered.
For the metals, however, the MDL procedure described by "Appendix D: DQ FAC
Single Laboratory Procedure v2.4" (FAC, 2007) was used to determine MDLs for chromium for
both quartz and Teflonฎ filter types, as well as manganese, cobalt, nickel, cadmium, and lead for
quartz filters. The method involves analyzing at least seven replicate samples extracted from
2-13
-------
blank sampling and calculating the MDLs from the results. For all other metals analytes, the
MDL procedure described in 40 CFR was used.
Tables 2-3 through 2-8 identify the specific target pollutants for each analytical method
and their corresponding MDLs. For the VOC and SNMOC analyses, the experimentally-
determined MDLs do not change within a given year unless the sample was diluted. The 2011
VOC and SNMOC MDLs are presented in Tables 2-3 and 2-4, respectively. For the rest of the
analyses, the MDLs vary due to the actual volume pulled through the sample or if the sample
was diluted. For these analyses, the range and average MDL is presented for each pollutant in
Tables 2-5 through 2-8, based on valid samples. ERG's published pollutant-specific MDLs are
also presented in Appendix B.
The following discussion presents an overview of the sampling and analytical methods.
For detailed descriptions of the methods, refer to EPA's original documentation of the
Compendium Methods (EPA, 1998; EPA, 1999a; EPA, 1999b; EPA, 1999c; EPA, 1999d; EPA,
2006).
2.2.1 VOC and SNMOC Concurrent Sampling and Analytical Methods
VOC and SNMOC sampling and analysis can be performed concurrently in accordance
with a combination of EPA Compendium Method TO-15 (EPA, 1999a) and the procedure
presented in EPA's "Technical Assistance Document for Sampling and Analysis of Ozone
Precursors" (EPA, 1998). When referring to SNMOC, this report may refer to this method as the
"concurrent SNMOC method" or "concurrent SNMOC analysis" because both methods were
often employed at the same time to analyze the same sample. Ambient air samples for VOC
and/or SNMOC analysis were collected in passivated stainless steel canisters. The ERG
laboratory distributed the prepared canisters (i.e., cleaned and evacuated) to the monitoring sites
before each scheduled sample collection event, and site operators connected the canisters to air
sampling equipment prior to each sample day. Prior to field sampling, the passivated canisters
had internal pressures much lower than atmospheric pressure. Using this pressure differential,
ambient air flowed into the canisters automatically once an associated system solenoid valve was
opened. A mass flow controller on the sampling device inlet ensured that ambient air entered the
canister at an integrated constant rate across the collection period. At the end of the 24-hour
2-14
-------
sampling period, the solenoid valve automatically closed and stopped ambient air from flowing
into the canister. Site operators recovered and returned the canisters, along with the Chain of
Custody forms and all associated documentation, to the ERG laboratory for analysis.
By analyzing each sample with gas chromatography incorporating mass spectrometry
(operating in the Selected Ion Monitoring (SIM) mode) and flame ionization detection
(GC/MS-FID), laboratory staff determined ambient air concentrations of 61 VOCs and/or 80
SNMOCs, and calculated the total nonmethane organic compounds (TNMOC) concentration.
TNMOC is the sum of all hydrocarbon concentrations within the sample. Because isobutene and
1-butene elute from the GC column at the same time, the SNMOC analytical method reports
only the sum concentration for these two compounds, and not the separate concentration for each
compound. The same approach applies to m-xylene and/>-xylene for both the VOC and
concurrent SNMOC methods. Raw data for both methods are presented in Appendices C and D.
Table 2-3 presents the MDLs for the laboratory analysis of VOC samples with Method
TO-15 and Table 2-4 presents the MDLs for the analysis of SNMOC samples. The MDL for
every VOC is lower than 0.16 parts per billion by volume (ppbv). SNMOC detection limits are
expressed in parts per billion Carbon (ppbC). All of the SNMOC MDLs are less than 0.45 ppbC.
2-15
-------
Table 2-3. 2011 VOC Method Detection Limits
Pollutant
Acetonitrile
Acetylene
Acrolein
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
2011
MDL
(ppbv)
0.0235
0.0163
0.0501
0.0116
0.0165
0.0288
0.0083
0.0247
0.0250
0.0091
0.0072
0.0331
0.0237
0.0212
0.0087
0.0088
0.0119
0.0389
0.0076
0.0207
Pollutant
1 ,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1, 1-Dichloroethene
c/'s-l,2-Dichloroethylene
/raซ5-l,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 , 3 -Dichloropropene
trans- 1 , 3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Aery late
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -Butadiene
Methyl Ethyl Ketone
2011
MDL
(ppbv)
0.0183
0.0342
0.0368
0.0348
0.0114
0.0084
0.0086
0.0088
0.0089
0.0081
0.0100
0.0227
0.0222
0.0246
0.0088
0.0200
0.0076
0.0169
0.0369
0.1570
Pollutant
Methyl Isobutyl Ketone
Methyl Methacrylate
Methyl tert-Butyl Ether
w-Octane
Propylene
Styrene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1,1,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
Vinyl Chloride
/w.^-Xylene1
o-Xylene
2011
MDL
(ppbv)
0.0223
0.0223
0.0083
0.0149
0.0393
0.0223
0.0244
0.0178
0.0162
0.0365
0.0222
0.0254
0.0254
0.0096
0.0109
0.0285
0.0262
0.0079
0.0336
0.0180
sum of/w-xylene and^-xylene concentrations and not concentrations of the individual isomers.
2-16
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Table 2-4. 2011 SNMOC Method Detection Limits1
Pollutant
Acetylene
Benzene
1,3 -Butadiene
w-Butane
c/s-2-Butene
/raws-2-Butene
Cyclohexane
Cyclopentane
Cyclopentene
w-Decane
1-Decene
/w-Diethylbenzene
ฃ>-Diethylbenzene
2,2-Dimethylbutane
2,3 -Dimethy Ibutane
2,3 -Dimethy Ipentane
2,4-Dimethylpentane
w-Dodecane
1-Dodecene
Ethane
2-Ethyl-l-butene
Ethylbenzene
Ethylene
/w-Ethyltoluene
o-Ethyltoluene
ฃ>-Ethyltoluene
w-Heptane
2011
MDL
(ppbC)1
0.080
0.220
0.190
0.190
0.170
0.141
0.189
0.124
0.190
0.200
0.200
0.200
0.120
0.140
0.210
0.440
0.230
0.430
0.430
0.090
0.330
0.180
0.290
0.170
0.190
0.250
0.190
Pollutant
1-Heptene
w-Hexane
1-Hexene
c/s-2-Hexene
/raซs-2-Hexene
Isobutane
Isobutene/ 1 -Butene2
Isopentane
Isoprene
Isopropylbenzene
2-Methy 1-1 -Butene
3 -Methy 1-1 -Butene
2-Methy 1- 1 -Pentene
4-Methyl- 1 -Pentene
2-Methyl-2-Butene
Methylcyclohexane
Methylcyclopentane
2-Methy Iheptane
3-Methylheptane
2-Methy Ihexane
3-Methylhexane
2-Methy Ipentane
3 -Methy Ipentane
w-Nonane
1-Nonene
w-Octane
1-Octene
2011
MDL
(ppbC)1
0.440
0.180
0.330
0.330
0.330
0.160
0.130
0.180
0.190
0.200
0.190
0.190
0.330
0.330
0.190
0.180
0.160
0.130
0.160
0.220
0.140
0.150
0.170
0.210
0.250
0.230
0.260
Pollutant
w-Pentane
1 -Pentene
c/s-2-Pentene
/raซs-2-Pentene
a-Pinene
6-Pinene
Propane
w-Propylbenzene
Propylene
Propyne
Styrene
Toluene
w-Tridecane
1-Tridecene
1,2,3-Trimethylbenzene
1,2,4-Trimethylbenzene
1 , 3 ,5 -Trimethy Ibenzene
2,2,3 -Trimethy Ipentane
2,2,4-Trimethy Ipentane
2,3,4-Trimethy Ipentane
w-Undecane
1-Undecene
7w-Xylene//?-Xylene2
o-Xylene
Sum of Knowns
Sum of Unknowns
TNMOC
2011
MDL
(ppbC)1
0.110
0.130
0.180
0.140
0.200
0.200
0.100
0.190
0.090
0.100
0.260
0.280
0.430
0.430
0.150
0.180
0.190
0.260
0.160
0.150
0.200
0.200
0.240
0.170
NA
NA
NA
1 Concentration in ppbC = concentration in ppbv * number of carbon atoms in the compound.
2 Because isobutene and 1-butene elute from the GC column at the same time, the SNMOC analytical method reports
the sum concentration for these two compounds and not concentrations of the individual compounds. For the same
reason, the /w-xylene and^-xylene concentrations are reported as a sum concentration.
NA = Not applicable
2-17
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2.2.2 Carbonyl Compound Sampling and Analytical Method
Following the specifications of EPA Compendium Method TO-11A (EPA, 1999b),
ambient air samples for carbonyl compound analysis were collected by passing ambient air
through an ozone scrubber and then through cartridges containing silica gel coated with
2,4-dinitrophenylhydrazine (DNPH), a compound known to react selectively and reversibly with
many aldehydes and ketones. Carbonyl compounds in ambient air are retained in the sampling
cartridge, while other compounds pass through the cartridge without reacting with the DNPH-
coated matrix. The ERG laboratory distributed the DNPH cartridges to the monitoring sites prior
to each scheduled sample collection event and site operators connected the cartridges to the air
sampling equipment. After each 24-hour sampling period, site operators recovered and returned
the cartridges, along with the Chain of Custody forms and all associated documentation, to the
ERG laboratory for analysis.
To quantify concentrations of carbonyl compounds in the sampled ambient air, laboratory
analysts extracted the exposed DNPH cartridges with acetonitrile. High-performance liquid
chromatography (HPLC) analysis and ultraviolet detection of these solutions determined the
relative amounts of individual carbonyl compounds present in the original air sample. Because
the three tolualdehyde isomers elute from the HPLC column at the same time, the carbonyl
compound analytical method reports only the sum concentration for these isomers, and not the
separate concentrations for each isomer. Raw data for Method TO-11A are presented in
Appendix E.
Table 2-5 lists the MDLs reported by the ERG laboratory for measuring concentrations
of 14 carbonyl compounds. Although the sensitivity varies from pollutant-to-pollutant and from
site-to-site due to the different volumes pulled through the samples, the average detection limit
for valid samples reported by the ERG laboratory for every pollutant is less than 0.01 ppbv.
2-18
-------
Table 2-5. 2011 Carbonyl Compound Method Detection Limits
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes1
Valeraldehyde
Minimum
MDL
(ppbv)
0.0040
0.0040
0.0010
0.0020
0.0020
0.0010
0.0060
0.0010
0.0009
0.0020
0.0020
0.0010
Maximum
MDL
(ppbv)
0.0300
0.0300
0.0100
0.0140
0.0140
0.0100
0.0840
0.0090
0.0070
0.0110
0.0140
0.0110
Average
MDL
(ppbv)
0.0068
0.0068
0.0024
0.0032
0.0032
0.0024
0.0099
0.0020
0.0014
0.0026
0.0033
0.0025
1 The three tolualdehyde isomers elute from the HPLC column at the same time; thus,
the analytical method reports only the sum concentration for these three isomers and
not the individual concentrations.
2.2.3 PAH Sampling and Analytical Method
PAH sampling and analysis was performed in accordance with EPA Compendium
Method TO-13A (EPA, 1999c) and ASTM D6209 (ASTM, 2013). The ERG laboratory prepared
sampling media and supplied them to the sites before each scheduled sample collection event.
The clean sampling PUF/XAD-2ฎ cartridge and glass fiber filter are installed in a high volume
sampler by the site operators and allowed to sample for 24 hours. Sample collection modules and
Chain of Custody forms and all associated documentation were returned to the ERG laboratory
after sample collection. Within 14 days of sampling, the filter and cartridge are extracted
together using a toluene in hexane solution using the Dionex Accelerated Solvent Extractor
(ASE) 350 or ASE 300. The sample extract is concentrated to a final volume of 1.0 milliliter
(mL). A volume of 1 microliter (uL) is injected into the GC/MS operating in the SIM mode to
analyze 22 PAHs. Raw data for Method TO-13A are presented in Appendix F.
Table 2-6 lists the MDLs for the 22 PAH target pollutants. PAH detection limits are
expressed in nanograms per cubic meter (ng/m3). Although the sensitivity varies from pollutant-
to-pollutant and from site-to-site due to the different volumes pulled through the samples, the
average detection limit for valid samples reported by the ERG laboratory ranged from
0.032 ng/m3 (pyrene) to 0.145 ng/m3 (naphthalene).
2-19
-------
Table 2-6. 2011 PAH Method Detection Limits
Pollutant
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Coronene
Cyclopenta[cd]pyrene
Dibenz(a,h)anthracene
Fluoranthene
Fluorene
9-Fluorenone
Indeno(l,2,3-cd)pyrene
Naphthalene
Perylene
Phenanthrene
Pyrene
Retene
Minimum
MDL
(ng/m3)
0.029
0.025
0.023
0.027
0.023
0.025
0.024
0.016
0.025
0.021
0.013
0.033
0.018
0.022
0.030
0.026
0.018
0.067
0.021
0.022
0.019
0.026
Maximum
MDL
(ng/m3)
0.545
0.483
0.625
0.904
0.887
0.465
0.451
0.780
0.640
0.416
0.863
0.718
0.800
0.406
0.561
0.484
0.754
1.570
0.865
0.409
0.349
0.481
Average
MDL
(ng/m3)
0.051
0.045
0.057
0.083
0.081
0.043
0.042
0.071
0.059
0.038
0.079
0.066
0.073
0.038
0.052
0.045
0.069
0.145
0.079
0.038
0.032
0.048
2.2.4 Metals Sampling and Analytical Method
Sampling for the determination of metals in or on particulate matter was performed by
the sites in accordance with EPA Compendium Method IO-3.5 (EPA, 1999d). Ambient air
samples for metals analysis were collected by passing ambient air through either 47mm Teflonฎ
filters or 8" x 10" quartz filters, depending on the separate and distinct sampling apparatus used
to collect the sample; the 47mm Teflonฎ filter is used for low-volume samplers, whereas the
8" x 10" quartz filter is used for high-volume samplers. EPA provides the filters to the
monitoring sites. Sites sampled for either parti culate matter less than 10 microns (PMio) or total
suspended particulate (TSP). Particulates in ambient air were collected on the filters and, after a
24-hour sampling period, site operators recovered and returned the filters, along with the Chain
of Custody forms and all associated documentation, to the ERG laboratory for analysis.
Upon receipt at the laboratory, the whole filters (47mm Teflonฎ) or filter strips
(8" x 10" quartz) were digested using a dilute nitric acid, hydrochloric acid, and/or hydrofluoric
2-20
-------
acid (Teflon only) solution. The digestate was then quantified using inductively coupled plasma
mass spectrometry (ICP-MS) to determine the concentration of individual metals present in the
original air sample. Raw data for speciated metals are presented in Appendix G.
Table 2-7 lists the MDLs for the analysis of the metals samples. Due to the difference in
sample volume/filter collection media, there are two sets of MDLs listed in Table 2-7. Although
the sensitivity varies from pollutant-to-pollutant and from site-to-site due to the different
volumes pulled through the samples, the average MDL for valid samples ranged from
0.007 ng/m3 (mercury) to 2.07 ng/m3 (chromium) for the quartz filters and from 0.010 ng/m3
(cadmium) to 8.14 ng/m3 (chromium) for the Teflonฎ filters.
Table 2-7. 2011 Metals Method Detection Limits
Pollutant
Minimum
MDL
(ng/m3)
Maximum
MDL
(ng/m3)
Average
MDL
(ng/m3)
8 X 10" Quartz Filters
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Cobalt
Lead
Manganese
Mercury
Nickel
Selenium
0.007
0.033
0.001
0.004
1.430
0.015
0.060
0.074
0.005
0.230
0.009
0.055
0.389
0.059
0.079
3.530
0.067
19.400
23.000
0.565
3.940
0.513
0.013
0.049
0.008
0.010
2.072
0.025
0.132
0.163
0.007
0.361
0.021
Pollutant
Minimum
MDL
(ng/m3)
Maximum
MDL
(ng/m3)
Average
MDL
(ng/m3)
47mm Teflonฎ Filters
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Cobalt
Lead
Manganese
Mercury
Nickel
Selenium
0.020
0.100
0.010
0.010
6.080
0.020
0.020
0.200
0.020
0.290
0.060
0.060
0.220
0.020
0.020
10.800
0.030
0.080
0.270
0.030
1.500
0.180
0.023
0.160
0.011
0.010
8.138
0.021
0.024
0.204
0.022
1.096
0.069
2.2.5 Hexavalent Chromium Sampling and Analytical Method
Hexavalent chromium was measured using an EPA-approved approach. For a detailed
description of the method, refer to the "Standard Operating Procedure for the Determination of
Hexavalent Chromium in Ambient Air Analyzed by Ion Chromatography (1C)" (EPA, 2006).
Ambient air samples for hexavalent chromium analysis were collected by passing ambient air
through sodium bicarbonate impregnated acid-washed cellulose filters. ERG prepared and
distributed filters secured in Teflonฎ cartridges to the monitoring sites prior to each scheduled
sample collection event and site operators connected the cartridges to the air sampling
equipment. After a 24-hour sampling period, site operators recovered the cartridges and Chain of
2-21
-------
Custody forms and returned them to the ERG laboratory for analysis. Upon receipt at the
laboratory, the filters were extracted using a sodium bicarbonate solution. Ion chromatography
(1C) analysis and ultraviolet-visible detection of these extracts determined the amount of
hexavalent chromium present in each sample.
Although the sensitivity varies from site-to-site due to the different volumes pulled
through the samples, the average detection limit for valid samples reported by the ERG
laboratory across the program, which is presented in Table 2-8, is 0.0040 ng/m3. Raw data for
the hexavalent chromium method are presented in Appendix H.
Table 2-8. 2011 Hexavalent Chromium Method Detection Limits
Pollutant
Hexavalent Chromium
Minimum
MDL
(ng/m3)
0.0024
Maximum
MDL
(ng/m3)
0.0081
Average
MDL
(ng/m3)
0.0040
2.3 Sample Collection Schedules
Table 2-9 presents the first and last date on which sample collection occurred for each
monitoring site sampling under the NMP in 2011. The first sample date for each site is generally
at the beginning of January 2011 and sampling continued through the end of December 2011,
although there were a few exceptions:
The San Jose, CA site (SJJCA) samples PMio metals under the NMP. However, in
December 2010, this site changed samplers. This site began sampling PMio metals
using a low-volume sampler with Teflonฎ filters on December 16, 2010 (rather than
the previous high-volume sampler with quartz filters). As a result, data from the three
December 2010 samples collected with the low-volume sampler have been included
with the 2011 data for this site.
The River Rouge and Detroit, MI sites (RRMI and SWMI) began sampling carbonyl
compounds under the NMP at the end of January.
In May, the Grayson, KY site (GLKY) began sampling PMio metals under the NMP,
in addition to VOCs, hexavalent chromium, and PAHs. This site also began sampling
carbonyl compounds under the NMP in August.
The Silt, CO site (BRCO) experienced carbonyl compound sampler problems,
delaying sampling until September 2011.
The Paterson, NJ site (PANJ) stopped sampling under the NMP in May.
2-22
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The Midwest City, OK site (MWOK) stopped sampling in November 2011 and the
instrumentation was moved to a different location in Oklahoma City. Because less
than one month of data was available for 2011 for this new site, data from the new
location are not included in the 2011 NMP annual report and will be included in the
2012 NMP report.
According to the NMP schedule, 24-hour integrated samples were to be collected at each
monitoring site every l-in-6 days (or l-in-12 days, dependent upon location and monitoring
objectives) and each sample collection began and ended at midnight, local standard time.
However, there were some exceptions:
The Garfield County, CO sites (BMCO, BRCO, PACO, RICO) collected samples by
initiating the samplers manually. For these sites, samples were generally collected
from mid-morning of one day to mid-morning of the next. In addition, SNMOC
samples were collected on a l-in-6 day schedule while carbonyl compounds were
collected on a l-in-12 day schedule.
The South Phoenix, AZ site (SPAZ) collected VOC samples on a l-in-12 day
schedule.
The Paterson, NJ site (PANJ) collected VOC samples on a l-in-12 day schedule.
The Orlando, FL site (PAFL) collected metals samples on a l-in-12 day schedule.
The Burlington, VT and Rutland, VT sites (BURVT and RUVT) collected VOC
samples on a l-in-12 day schedule.
2-23
-------
Table 2-9. 2011 Sampling Schedules and Completeness Rates
Site
AZFL
BMCO
BOMA
BRCO
BTUT
BURVT2
CAMS 35
CAMS 85
CELA
CHNJ
CHSC
DEMI
ELNJ
GLKY
Monitoring Period1
First
Sample
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/9/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
Last
Sample
12/31/11
12/29/11
12/29/11
12/29/11
12/29/11
12/23/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
Carbonyl
Compounds
A
62
20
_
6
60
_
_
61
62
61
26
B
61
30
9
61
_
61
61
61
26
C
>100
672
672
98
100
>100
100
100
voc
A
_
60
30
61
61
61
61
B
61
30
_
_
61
61
61
61
C
98
100
_
_
100
100
100
100
Hexavalent
Chromium
A
61
61
60
61
60
61
61
B
61
61
61
61
_
61
61
61
C
100
100
98
100
98
100
100
Metals
A
_
60
60
41
B
61
61
_
41
C
98
98
100
SNMOC
A
51
54
60
_
B
61
61
61
_
C
_
84
89
98
PAH
A
61
62
58
59
60
60
61
B
61
61
61
61
61
61
_
61
C
100
>100
95
97
98
98
100
to
to
A = Number of valid samples collected.
B = Number of valid samples that should be collected in 2011 based on sample schedule and start/end date of sampling.
C = Completeness (%).
1 Begins with 1st sample collected and ends with last sample collected; date range presented may not be representative of each method-specific date range.
Sampling schedule was a l-in-12 day schedule rather than a l-in-6 schedule.
Includes three samples from December 2010.
BOLD ITALICS = EPA-designated NATTS site.
Shading indicates that completeness is below the MQO of 85%.
-------
Table 2-9. 2011 Sampling Schedules and Completeness Rates (Continued)
Site
GPCO
HOW
INDEM
MONY
MWOK
NBIL
NBNJ
OCOK
ORFL
PACO
PAFL2
PANJ2
PROK
PRRI
PXSS
Monitoring Period1
First
Sample
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
1/3/11
Last
Sample
12/29/11
12/29/11
12/29/11
12/29/11
11/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
5/15/11
12/29/11
12/29/11
12/29/11
Carbonyl
Compounds
A
60
57
56
62
62
60
60
21
_
_
58
_
48
B
61
61
56
61
61
61
61
30
_
_
61
61
C
98
93
100
>100
>100
98
98
702
95
79
voc
A
60
56
55
58
61
_
12
56
61
B
61
56
61
61
61
12
61
_
61
C
98
100
90
95
100
_
100
92
100
Hexavalent
Chromium
A
59
61
61
61
57
62
B
61
61
61
61
61
61
C
97
100
100
100
_
93
>100
Metals
A
_
_
56
53
61
31
_
56
61
B
56
61
_
61
31
61
61
C
100
87
100
100
92
100
SNMOC
A
54
53
_
B
61
61
C
_
89
87
_
_
PAH
A
61
60
61
57
57
B
61
_
61
61
_
_
_
_
_
60
61
C
100
98
100
95
93
to
to
A = Number of valid samples collected.
B = Number of valid samples that should be collected based on sample schedule and start/end date of sampling.
C = Completeness (%).
1 Begins with 1st sample collected and ends with last sample collected; date range presented may not be representative of each method-specific date range.
Sampling schedule was a l-in-12 day schedule rather than a l-in-6 schedule.
Includes three samples from December 2010.
BOLD ITALICS = EPA-designated NATTS site.
Shading indicates that completeness is below the MQO of 85%.
-------
Table 2-9. 2011 Sampling Schedules and Completeness Rates (Continued)
Site
RICO
RIVA
ROCH
RRMI
RUCA
RUVT2
S4MO
SDGA
SEWA
SJJCA3
SKFL
SPAZ2
SPIL
SSSD
SWMI2
Monitoring Period1
First
Sample
1/3/11
1/3/11
1/3/11
1/21/11
1/3/11
1/9/11
1/3/11
1/3/11
1/3/11
12/16/10
1/3/11
1/6/11
1/3/11
1/3/11
1/27/11
Last
Sample
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/23/11
12/29/11
12/31/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
Carbonyl
Compounds
A
17
_
57
59
60
61
62
59
28
B
30
_
58
61
61
61
61
61
29
C
572
98
97
98
100
>100
97
97
voc
A
_
30
57
61
31
56
60
B
30
61
61
31
61
61
C
_
100
93
100
100
92
98
Hexavalent
Chromium
A
61
56
61
61
61
62
B
_
61
61
61
61
61
61
C
100
92
_
100
100
100
>100
Metals
A
_
59
61
64
_
B
61
61
64
C
_
_
97
100
100
SNMOC
A
53
_
60
B
61
61
C
87
_
98
PAH
A
61
58
61
61
61
60
61
61
B
_
61
61
61
61
61
61
61
61
_
C
100
95
100
100
100
98
100
100
to
to
A = Number of valid samples collected.
B = Number of valid samples that should be collected based on sample schedule and start/end date of sampling.
C = Completeness (%).
1 Begins with 1st sample collected and ends with last sample collected; date range presented may not be representative of each method-specific date range.
Sampling schedule was a l-in-12 day schedule rather than a l-in-6 schedule.
Includes three samples from December 2010.
BOLD ITALICS = EPA-designated NATTS site.
Shading indicates that completeness is below the MQO of 85%.
-------
Table 2-9. 2011 Sampling Schedules and Completeness Rates (Continued)
Site
SYFL
TMOK
TOOK
UCSD
UNVT
WADC
WPIN
Monitoring Period1
First
Sample
1/3/11
1/3/11
1/3/11
1/6/11
1/3/11
1/3/11
1/3/11
Last
Sample
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
12/29/11
Carbonyl
Compounds
A
60
61
56
61
_
_
51
B
61
61
61
61
_
61
C
98
100
92
100
84
voc
A
60
57
56
60
B
_
61
61
61
61
_
C
_
98
93
92
98
_
Hexavalent
Chromium
A
59
60
61
B
61
61
61
C
97
98
100
Metals
A
58
56
57
_
B
61
61
61
C
95
92
93
SNMOC
A
56
B
_
61
C
92
PAH
A
60
60
61
B
61
61
61
C
98
_
98
100
A = Number of valid samples collected.
to B = Number of valid samples that should be collected based on sample schedule and start/end date of sampling.
K> C = Completeness (%).
1 Begins with 1st sample collected and ends with last sample collected; date range presented may not be representative of each method-specific date range.
Sampling schedule was a l-in-12 day schedule rather than a l-in-6 schedule.
Includes three samples from December 2010.
BOLD ITALICS = EPA-designated NATTS site.
Shading indicates that completeness is below the MQO of 85%.
-------
Table 2-9 shows the following:
24 sites collected VOC samples and 31 sites collected carbonyl compound samples;
VOC and carbonyl compound samples were collected concurrently at 19 sites.
8 sites collected SNMOC samples.
23 sites collected PAH samples.
15 sites collected metals samples.
22 sites collected hexavalent chromium samples.
As part of the sampling schedule, site operators were instructed to collect duplicate (or
collocated) samples on roughly 10 percent of the sample days for select methods when duplicate
(or collocated) samplers were available. Field blanks were collected once a month for carbonyl
compounds, hexavalent chromium, metals, and PAHs. Sampling calendars were distributed to
help site operators schedule the collection of samples, duplicates, and field blanks. In cases
where a valid sample was not collected for a given scheduled sample day, site operators were
instructed to reschedule or "make up" samples on other days. This practice explains why some
monitoring locations periodically strayed from the l-in-6 or l-in-12 day sampling schedule.
The l-in-6 or l-in-12 day sampling schedule provides cost-effective approaches to data
collection for trends characterization of toxic pollutants in ambient air and ensures that sample
days are evenly distributed among the seven days of the week to allow weekday/weekend
comparison of air quality. Because the l-in-6 day schedule yields twice the number of
measurements than the l-in-12 day schedule, data characterization based on this schedule tends
to be more representative.
2.4 Completeness
Completeness refers to the number of valid samples collected and analyzed compared to
the number of total samples expected based on a l-in-6 or l-in-12 day sample schedule.
Monitoring programs that consistently generate valid samples have higher completeness than
programs that consistently have invalid samples. The completeness of an air monitoring
program, therefore, can be a qualitative measure of the reliability of air sampling and laboratory
2-28
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analytical equipment as well as a measure of the efficiency with which the program is managed.
The completeness for each monitoring site and method sampled is presented in Table 2-9.
The measurement quality objective (MQO) for completeness based on the EPA-approved
Quality Assurance Project Plan (QAPP) specifies that at least 85 percent of samples from a given
monitoring site must be collected and analyzed successfully to be considered sufficient for data
trends analysis (ERG, 2011). The data in Table 2-9 show that seven datasets from a total of 123
datasets from the 2011 NMP monitoring sites did not meet this MQO (shaded cells in Table 2-9):
Four of the seven site-method combinations for which completeness was less than
85 percent were for Garfield County carbonyl compound sites (BRCO, BMCO,
PACO, and RICO). These sites tended to experience issues with their carbonyl
compound samplers. Prolonged issues resulted in BRCO sampling carbonyl
compounds for only four months out of the year.
Canister issues and several missed sample days led to a completeness less than
85 percent for BMCO SNMOC.
Maintenance of the primary carbonyl compound sampler at PXSS in 2010 led to a
problem with the ozone denuder. As a result, the primary sampling results from mid-
February 2010 through March 2011 were invalidated.
Intermittent sampler issues throughout 2011 resulted in a carbonyl compound
completeness less than 85 percent for WPIN.
Although the completeness for S4MO's VOC is 93 percent, it should be noted that the
Missouri Department of Natural Resources discovered a sampler contamination issue and
invalidated all of its acrylonitrile results for this site. This is discussed in more detail in the
Missouri state section (Section 16).
Appendix I identifies samples that were invalidated and lists the reason for invalidation,
based on the applied AQS null code.
Table 2-10 presents method-specific completeness. Method-specific completeness was
greater than 90 percent for all six methods performed under the 2011 NMP and ranged from
90.37 percent for SNMOC to 98.96 percent for hexavalent chromium.
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Table 2-10. Method Completeness Rates for 2011
Method
voc
SNMOC
Carbonyl Compounds
PAH
Metals Analysis
Hexavalent Chromium
# of Valid
Samples
1,281
441
1,594
1,382
834
1,328
#of
Samples
Scheduled
1,318
488
1,671
1,402
863
1,342
Method
Completeness
(%)
97.19
90.37
95.39
98.57
96.64
98.96
Minimum
Site-Specific
Completeness
(%)
90.16
(NBNJ)
83.60
(BMCO)
56.67
(RICO)
93.44
(PXSS)
86.89
(NBIL)
91.80
(ROCH)
Maximum
Site-Specific
Completeness
(%)
100.00
(12 sites)
98.36
(BTUT)
>100
(5 sites)
>100
(BTUT)
100.00
(7 sites)
>100
(2 sites)
2-30
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3.0
Summary of the 2011 National Monitoring Programs Data Treatment and Methods
This section summarizes the data treatment
and approaches used to evaluate the measurements
generated from samples collected during the 2011
NMP sampling year. These data were analyzed on
a program-wide basis as well as a site-specific
basis.
Results from the program-wide data
analyses are presented in Section 4
and results from the site-specific data
analyses are presented in the
individual state sections, Sections 5
through 28.
A total of 218,948 valid air toxics concentrations (including non-detects, duplicate
analyses, replicate analyses, and analyses for collocated samples) were produced from 8,835
valid samples collected at 51 monitoring sites during the 2011 reporting year. A tabular
presentation of the raw data and statistical summaries are found in Appendices C through O, as
presented in Table 3-1. Appendix P serves as the glossary for the NMP report and many of the
terms discussed and defined throughout the report are provided here.
Table 3-1. Overview and Layout of Data Presented
Pollutant Group
VOCs
SNMOCs
Carbonyl Compounds
PAHs
Metals
Hexavalent Chromium
Number of Sites
24
8
31
23
15
22
Appendix
Raw Data
C
D
E
F
G
H
Statistical Summary
J
K
L
M
N
O
3.1 Approach to Data Treatment
This section examines the various statistical tools employed to characterize the data
collected during the 2011 sampling year. Certain data analyses were performed at the program-
level, other data analyses were performed at both the program-level and on a site-specific basis,
and still other approaches were reserved for site-specific data analyses only. Regardless of the
data analysis employed, it is important to understand how the concentration data were treated.
The following paragraphs describe techniques used to prepare this large quantity of
concentration data for data analysis.
5-1
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For each monitoring site, the primary, duplicate (or collocated), and replicate
measurements were averaged together for each pollutant in order to calculate a single
concentration per sample date and method. This is referred to as thepreprocessed daily
measurement.
Concentrations of m,/>-xylene and o-xylene were summed together and are henceforth
referred to as "total xylenes," "xylenes (total)," or simply "xylenes" throughout the remainder of
this report, with a few exceptions. One exception is Section 4.1, which examines the results of
basic statistical calculations performed on the dataset. Table 4-1 and Table 4-2, which are the
method-specific statistics for VOCs and SNMOCs, respectively, present the xylenes results
retained as m,/>-xylene and o-xylene species. This is also true of the Data Quality
section (Section 29).
For the 2011 NMP, where statistical parameters are calculated based on the preprocessed
daily measurements, zeros have been substituted for non-detect results. In past reports, the
substitution of zeros was applied only to risk-related analyses; however, in the 2010 and 2011
NMP reports, the substitution of zeros was applied to all analyses. This approach is consistent
with how data are loaded into AQS per the NATTS TAD (EPA, 2009b) as well as other EPA air
toxics monitoring programs such as the School Air Toxics Monitoring Program (SATMP)
(EPA, 201 la) and the NATTS Network Assessment (EPA, 2012f). The substitution of zeros for
non-detects results in lower average concentrations of pollutants that are rarely measured at or
above the associated method detection limit and/or have a relatively high MDL.
In order to compare concentrations across multiple sampling methods, all concentrations
have been converted to a common unit of measure: microgram per cubic meter (ug/m3).
However, whenever a particular sampling method is isolated from others, such as in Tables 4-1
through 4-6, the statistical parameters are presented in the units of measure associated with the
particular sampling method. As such, it is important to pay close attention to the unit of measure
associated with each data analysis discussed in this and subsequent sections of the report.
5-2
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In addition, this report presents various time-based averages to summarize the
measurements for a specific site; where applicable, quarterly and annual averages were
calculated for each site. The quarterly average of a particular pollutant is simply the average
concentration of the preprocessed daily measurements over a given calendar quarter. Quarterly
averages include the substitution of zeros for all non-detects. Quarterly averages for the first
quarter in the calendar year include concentrations from January, February, and March; the
second quarter includes April, May, and June; the third quarter includes July, August, and
September; and the fourth quarter includes October, November, and December. A site must have
a minimum of 75 percent valid samples of the total number of samples possible within a given
quarter to have a quarterly average. For sites sampling on a l-in-6 day sampling schedule,
12 samples represents 75 percent; for sites sampling on a l-in-12 day schedule, six samples
represents 75 percent. Sites that do not meet these minimum requirements do not have a
quarterly average concentration presented. Sites may not meet this minimum requirement due to
invalidated or missed samples or because of a shortened sampling duration.
An annual average includes all measured detections and substituted zeros for non-detects
for a given calendar year (2011). Annual average concentrations were calculated for monitoring
sites where three quarterly averages could be calculated and where method completeness was
greater than or equal to 85 percent. Sites that do not meet these requirements do not have an
annual average concentration presented.
The concentration averages presented in this report are often provided with their
associated 95 percent confidence intervals. Confidence intervals represent the interval within
which the true average concentration falls 95 percent of the time. The confidence interval
includes an equal amount of quantities above and below the concentration average. For example,
an average concentration may be written as 1.25 ฑ 0.25 |ig/m3; thus, the interval over which the
true average would be expected to fall would be between 1.00 to 1.50 |ig/m3 (EPA, 201 la).
3.2 Human Health Risk and the Pollutants of Interest
A practical approach to making an assessment on a large number of measurements is to
focus on a subset of pollutants based on the end-use of the dataset. Thus, a subset of pollutants is
selected for further data analyses for each annual NMP report. In NMP annual reports prior to
3-3
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2003, this subset was based on the frequency and magnitude of concentrations (previously called
"prevalent compounds"). Since the 2003 NMP annual report, health risk-based calculations have
been used to identify "pollutants of interest." For the 2011 NMP report, the pollutants of interest
are also based on risk potential. The following paragraphs provide an overview of health risk
terms and concepts and outline how the pollutants of interest are determined and then used
throughout the remainder of the report.
EPA defines risk as "the probability that damage to life, health, or the environment will
occur as a result of a given hazard (such as exposure to a toxic chemical)" (EPA, 201 Ib). Human
health risk can be defined in terms of time. Chronic effects develop from repeated exposure over
long periods of time; acute effects develop from a single exposure or from exposures over short
periods of time (EPA, 2010a). Health risk is also route-specific; that is, risk varies depending
upon route of exposure (i.e., oral vs. inhalation). Because this report covers air toxics in ambient
air, only the inhalation route is considered. Hazardous air pollutants (HAPs) are those pollutants
"known or suspected to cause cancer or other serious health effects, such as reproductive effects
or birth defects, or adverse environmental effects" (EPA, 2012g).
Health risks are typically divided into cancer and noncancer effects when referring to
human health risk. Cancer risk is defined as the likelihood of developing cancer as a result of
exposure to a given concentration over a 70-year period, and is presented as the number of
people at risk for cancer per million people. Noncancer health effects include conditions such as
asthma; noncancer health risks are presented as a hazard quotient, the value below which no
adverse health effects are expected (EPA, 201 Ib). Cancer risk is presented as a probability while
the hazard quotient is a ratio and thus, a unitless value.
In order to assess health risk, EPA and other agencies develop toxicity factors, such as
cancer unit risk estimates (UREs) and noncancer reference concentrations (RfCs), to estimate
cancer and noncancer risks and to identify (or screen) where air toxics concentrations may
present a human health risk. EPA has published a guidance document outlining a risk-based
screening approach that utilizes a risk-based methodology for performing an initial screen of
ambient air toxics monitoring datasets (EPA, 2010a). This preliminary risk-based screening
process provides a risk-based methodology for analysts and interested parties to identify which
3-4
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pollutants may pose a risk in their area. Cancer UREs and noncancer RfCs are used as screening
values. Not all pollutants analyzed under the NMP have screening values; of the 177 pollutants
sampled under the NMP, 81 pollutants have screening values in the guidance document. The
screening values used in this analysis are presented in Appendix Q1.
The preprocessed daily measurements of the target pollutants were compared to these
chronic risk screening values in order to identify pollutants of interest across the program. The
following risk-based screening process was used to identify pollutants of interest:
1. The TO-15 and SNMOC methods have 12 pollutants in common. If a pollutant was
measured by both the TO-15 and SNMOC methods at the same site, the TO-15
results were used. The purpose of this data treatment is to have one concentration per
pollutant for each sample day.
2. Each preprocessed daily measurement was compared to the risk screening value.
Concentrations that are greater than the risk screening value are described as "failing
the screen."
3. The number of failed screens was summed for each applicable pollutant.
4. The percent contribution of the number of failed screens to the total number of failed
screens program-wide was calculated for each applicable pollutant.
5. The pollutants contributing to the top 95 percent of the total failed screens were
identified as pollutants of interest.
In regards to Step 5 above, the actual cumulative contribution may exceed 95 percent in
order to include all pollutants contributing to the minimum 95 percent criteria (refer to
hexachloro-1,3-butadiene in Table 4-7 for an example). In addition, if the 95 percent cumulative
criterion is reached, but the next pollutant contributed equally to the number of failed screens,
that pollutant was also designated as a pollutant of interest. Results of the program-wide risk-
based screening process are provided in Section 4.2.
Laboratory analysts have indicated that acetonitrile values may be artificially high (or
non-existent) due to site conditions and potential cross-contamination with concurrent sampling
of carbonyl compounds using Method TO-11 A. The inclusion of acetonitrile in data analysis
1 The risk-based screening process used in this report comes from guidance from EPA Region 4's report "A
Preliminary Risk-Based Screening Approach for Air Toxics Monitoring Datasets" but the screening values
referenced in that report have since been updated (EPA, 2012h).
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calculations must be determined on a site-specific basis by the agency responsible for the site.
Thus, acetonitrile results are excluded from certain program-wide and site-specific data analyses,
particularly those related to risk.
In addition to the preliminary risk-based screening process described above, the
pollutants of interest designation was further refined based on the NATTS TAD (EPA, 2009b).
This document identifies 19 pollutants ("MQO Core Analytes") that participating sites are
required to sample and analyze for under the NATTS program. Table 3-2 presents these 19
NATTS MQO Core Analytes. Monitoring for these pollutants is required because they are major
health risk drivers according to EPA (EPA, 2009b).
Table 3-2. NATTS MQO Core Analytes
Pollutant
Acrolein
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Acetaldehyde
Formaldehyde
Naphthalene
Benzo(a)pyrene
Arsenic
Beryllium
Cadmium
Manganese
Lead
Nickel
Hexavalent chromium
Class/Method
VOCs/TO-15
Carbonyl Compounds/
TO-11A
PAHs/TO-13A
Metals/IO-3.5
Metals/EPA
-------
With the exception of acrolein, all of the pollutants listed in Table 3-2 are inherently
considered pollutants of interest due to their designation as NATTS MQO Core Analytes. If a
pollutant listed in Table 3-2 did not meet the pollutant of interest criteria based on the
preliminary risk-based screening approach outlined above, that pollutant was added to the list of
program-wide pollutants of interest.
Although it is a NATTS MQO Core Analyte, acrolein was excluded from the preliminary
risk-based screening process due to questions about the consistency and reliability of the
measurements (EPA, 201 Ob). Thus, the results from sampling and analysis of this pollutant have
been excluded from any risk-related analyses presented in this report, similar to acetonitrile (as
discussed above).
The "pollutants of interest" designation is reserved for pollutants targeted for sampling
through the NMP that meet the identified criteria. As discussed in Section 2.0, agencies
operating monitoring sites that participate under the NMP are not required to have their samples
analyzed by EPA's national contract laboratory or may measure analytes other than
those targeted under the NMP. In these cases, data are generated by sources other than ERG and
are not included in the preliminary risk-based screening process or any other data analysis
contained in this report.
3.3 Noncancer Risk-Based Screening Evaluation Using Minimum Risk Levels
In addition to the preliminary risk-based screening process described above, a second
risk-based screening was conducted using the Agency for Toxic Substances and Disease
Registry (ATSDR) Minimal Risk Level (MRL) health benchmarks (ATSDR, 2012a). An MRL is
a concentration of a hazardous substance that is "likely to be without appreciable risk of adverse
noncancer health effects over a specified duration of exposure," similar to EPA's RfCs (ATSDR,
2012b). MRLs are intended to be used as screening tools, similar to the preliminary risk-based
screening process discussed above, where "exposure to a level above the MRL does not mean
that adverse health effects will occur" (ATSDR, 2012b). ATSDR defines MRLs for three
durations of exposure: acute, intermediate, and chronic exposure. Acute risk results from
exposures of 1 to 14 days; intermediate risk results from exposures of 15 to 364 days; and
chronic risk results from exposures of 1 year or greater (ATSDR, 2012b). MRLs, as published by
3-7
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ATSDR, are presented in parts per million (ppm) for gases and milligrams per cubic meter
(mg/m3) for particulates. The MRLs used in this report have been converted to |ig/m3, have one
significant figure, and are presented in Appendix Q.
For this risk-based screening evaluation, the preprocessed daily measurements were
compared to acute MRLs; quarterly averages were compared to intermediate MRLs; and annual
averages were compared to chronic MRLs. Section 4.2.2 presents the number of preprocessed
daily measurements, quarterly averages, and/or annual averages that are greater than their
respective MRL for each pollutant, summed to the program level. The number of site-specific
concentrations and/or time period averages that are greater than their respective MRLs is
expanded upon in the individual state sections.
3.4 Additional Program-Level Analyses of the 2011 National Monitoring Programs
Dataset
This section summarizes additional analyses performed on the 2011 NMP dataset at the
program level. Additional program-level analyses include an examination of the potential effect
of motor vehicles and a review of how concentrations vary among the sites themselves and from
quarter-to-quarter. The results of these analyses are presented in Sections 4.3 and 4.4.
3.4.1 The Effect of Mobile Source Emissions on Spatial Variations
Mobile source emissions from motor vehicles contribute significantly to air pollution.
"Mobile sources" refer to emitters of air pollutants that move, or can be moved, from place to
place and include both on-road and non-road emissions (EPA, 2012i). Pollutants found in motor
vehicle exhaust generally result from incomplete combustion of vehicle fuels. Although modern
vehicles and, more recently, vehicle fuels have been engineered to minimize air emissions, all
motor vehicles with internal combustion engines emit a wide range of pollutants. The magnitude
of these emissions primarily depends on the volume of traffic, while the chemical profile of these
emissions depends more on vehicle design and fuel formulation. This report uses a variety of
parameters to quantify and evaluate the effect of motor vehicle emissions on ambient air quality,
which are discussed further in Section 4.3:
Emissions data from the NEI
Total hydrocarbon concentrations
-------
Motor vehicle ownership data
Estimated daily traffic volume
Vehicle miles traveled (VMT).
This report uses Pearson correlation coefficients to measure the degree of correlation
between two variables, such as the ones listed above. By definition, Pearson correlation
coefficients always lie between -1 and +1. Three qualification statements apply:
A correlation coefficient of-1 indicates a perfectly "negative" relationship, indicating
that increases in the magnitude of one variable are associated with proportionate
decreases in the magnitude of the other variable, and vice versa.
A correlation coefficient of+1 indicates a perfectly "positive" relationship, indicating
that the magnitudes of two variables both increase and both decrease proportionately.
Data that are completely uncorrelated have Pearson correlation coefficients of 0.
Therefore, the sign (positive or negative) and magnitude of the Pearson correlation coefficient
indicate the direction and strength, respectively, of data correlations. In this report, correlation
coefficients greater than or equal to 0.50 and less than or equal to -0.50 are classified as strong,
while correlation coefficients less than 0.50 and greater than -0.50 are classified as weak.
The number of observations used in a calculation is an important factor to consider when
analyzing the correlations. A correlation using relatively few observations may skew the
correlation, making the degree of correlation appear higher (or lower) than it may actually be.
Thus, in this report, a minimum of five data points must be available to present a correlation.
3.4.2 Variability Analyses
Variability refers to the degree of difference among values in a dataset. Three types of
variability are analyzed for this report. The first type examines the coefficient of variation (CV)
for each of the program-level pollutants of interest across the program sites. The CV provides a
relative measure of variability by expressing the standard deviation to the magnitude of the
arithmetic mean for each of the program-level pollutants of interest, as identified in Section 4.2.
It is particularly useful when comparing different sets of data because it is unitless (Pagano, P.
and Gauvreau, K., 2000). In this report, variability across data distributions for different sites and
3-9
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different pollutants are compared. The CVs are shown in the form of scatter plots, where data
points represent the CV and a trend line is plotted to show linearity. In addition, the "R2" value is
also shown on each scatter plot. R2 is the coefficient of determination and is an indicator of how
dependant one variable is on the other. If R2 is equal to 1.0, the data exhibit perfect linearity; the
lower R2, the less dependent the variables are each other (Pagano, P. and Gauvreau, K., 2000).
Pollutants of interest whose data points are clustered together indicate uniformity in how the
concentrations are dispersed among the sites. This suggests that concentrations are affected by
typical and consistent sources (e.g., mobile sources). Data points that are not clustered suggest
the likelihood of a stationary source not typically found in most urban areas (e.g., coke
manufacturing facility).
The second type of variability assessed in this report is inter-site variability and is paired
with the CV analysis in Section 4.4. The annual average concentration for each site is plotted in
the form of a bar graph for each program-wide pollutant of interest. The criteria for calculating
an annual average is discussed in Section 3.1 and sites that do not meet these requirements do
not have an annual average concentration presented. This assessment allows the reader to
visualize how concentrations varied across the sites for a particular pollutant of interest. In order
to further this analysis, the program-level average concentrations, as presented in Tables 4-1
through 4-6 in Section 4.1, are plotted against the site-specific annual averages. This allows the
reader to see how the site-specific annual averages compared to the program-level average for
each pollutant. Note that the average concentrations shown for VOCs, SNMOCs, and carbonyl
compounds in Tables 4-1 through 4-3 are presented in method-specific units, but have been
converted to a common unit of measurement (|ig/m3) for the purposes of this analysis.
Quarterly variability is the third type of variability assessed in this report. The
concentration data for each site were divided into the four quarters of the year, as described in
Section 3.1. The completeness criteria, also described in Section 3.1, are maintained here as well.
The site-specific quarterly averages are illustrated by bar graphs for each program-level pollutant
of interest. This analysis allows for a determination of a quarterly (or seasonal) correlation with
the magnitude of concentrations for a specific pollutant.
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3.4.3 Greenhouse Gas Assessment
Currently, there is considerable discussion about climate change among atmospheric and
environmental scientists. Climate change refers to an extended period of change in
meteorological variables used to determine climate, such as temperature and precipitation.
Researchers are typically concerned with greenhouse gases (GHGs), which are those that cause
heat to be retained in the atmosphere (EPA, 2012J).
Agencies researching the effects of greenhouse gases tend to concentrate primarily on
tropospheric levels of these gases. The troposphere is the lowest level of the atmosphere, whose
height varies depending on season and latitude. This is also the layer in which weather
phenomenon occur (NOAA, 2013a). A few VOCs measured with Method TO-15 are greenhouse
gases, although these measurements reflect the concentration at the surface, or in the breathing
zone, and do not represent the entire troposphere. Section 4.5 presents the 10 GHGs currently
measured with Method TO-15, their Global Warming Potential (GWP), and the average
concentration across the NMP program. GWP is a way to determine a pollutant's ability to retain
heat relative to carbon dioxide, which is one of the predominant anthropogenic GHGs in the
atmosphere; higher GWPs indicate a higher potential contribution to global warming (EPA,
2012J). In the future, additional GHG pollutants may be added to the NMP Method TO-15 target
pollutant list in order to assess their surface-level ambient concentrations.
3.5 Additional Site-Specific Analyses
In addition to many of the analyses described in the preceding sections, the state-specific
sections contain additional analyses that are applicable only at the local level. This section
provides an overview of these analyses but does not discuss their results. Results of these site-
specific analyses are presented in the individual state-specific sections (Sections 5 through 28).
3.5.1 Site Characterization
For each site participating in the 2011 NMP, a site characterization was performed. This
analysis includes a review of the nearby area surrounding the monitoring site; plotting of
emissions sources surrounding the monitoring site; and obtaining population, vehicle
registration, traffic data, and other characterizing information.
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Regarding the plotting of emissions sources: for the 2011 (and 2010) NMP report, the
locations of point sources located near the monitoring sites were obtained from Version 2 of the
2008 NEI (EPA, 2012d). The 2008 NEI was compiled using a more streamlined approach by
EPA from state, local, and tribal agencies, as well as limited emission inventory data from other
federal programs, such as EPA's Toxics Release Inventory (TRI). By comparison, the 2008-2009
NMP report used Version 3 of the 2005 NEI, which included additional datasets not available for
the 2008 NEI. Thus, the total number of emission sources surrounding the monitoring sites is
generally lower in the 2008 NEI vs. the 2005 NEI. When comparing facility maps and emission
estimates presented in the 2011 (and 2010) NMP report to those presented in the 2008-2009
NMP report, it should be noted that the emissions inventory used in each report was for different
base years and was compiled differently.
3.5.2 Meteorological Analysis
Several site-specific meteorological analyses were performed in order to help readers to
determine which meteorological factors may play a role in a given site's air quality. First, an
overview of the general climatology is provided, based on the area where each site in located, to
give readers a general idea of what types of meteorological conditions likely affect the site. Next,
the average (or mean) for several meteorological parameters (such as temperature and relative
humidity) are provided. Two averages are presented for each parameter, one average for all days
in 2011 and one average for sample days only. These two averages allow for the determination
of how meteorological conditions on sample days varied from typical conditions throughout the
year. These averages are based on hourly meteorological observations collected from the
National Weather Service (NWS) weather station nearest each site and obtained from the
National Climatic Data Center (NCDC, 2010 and 2011). Although some monitoring sites have
meteorological instruments on-site and report these data to AQS, NWS data were chosen for this
analysis for several reasons:
Some sites do not have meteorological instruments on-site.
Some sites collect meteorological data but do not report them to AQS; thus, they are
not readily available.
There are differences among the sites in the meteorological parameters reported to
AQS.
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Although there are limitations to using NWS data, the data used is standardized and quality-
assured per NWS protocol.
In addition to the climate summary and the statistical calculations performed on
meteorological observations collected near each monitoring site, the following sections describe
additional meteorological analyses that were performed for each monitoring site. These analyses
were performed to further characterize the meteorology at or near each monitoring site and to
determine if the meteorological conditions on days samples were collected were representative
of conditions typically experienced near each site.
3.5.2.1 Back Trajectory Analysis
For all sites sampling under the NMP for 2011, a back trajectory analysis was conducted.
A back trajectory traces the origin of an air parcel in relation to the location where it is currently
being measured. The method of constructing a back trajectory uses the Lagrangian frame of
reference. In simplest terms, an air parcel can be traced back 1 hour to a new point of reference
based on the current measured wind speed and direction. At this new point of reference (that is
now 1 hour prior to the current observation), the wind speed and direction are used again to
determine where the air was 1 hour before. Back trajectory calculations are also governed by
other meteorological parameters, such as pressure and temperature. Each time segment is
referred to as a "time step."
Gridded meteorological data and the model used for back trajectory analyses were
prepared and developed by the National Oceanic and Atmospheric Administration (NOAA)
using data from the NWS and other cooperative agencies. The model used is the Hybrid Single-
Particle Lagrangian Integrated Trajectory (HYSPLIT) model (Draxler, R.R. and Rolph, G.D.,
1997 and 1998; Draxler, R.R., 1999). Back trajectories were computed using the HYPLIT model
to represent four times for each sample day, one at OOZ, 06Z, 12Z, and 18Z. "Z" time is "Zulu
Time" and the same time as UTC (Universal Time Coordinated) or GMT (Greenwich Mean
Time), or the local time at the prime meridian (NOAA, 2013a). Although back trajectories can
be modeled for extended periods of time, trajectories were constructed for durations of 24 hours
to match the 24-hour sampling duration. Trajectories are modeled with an initial height of
50 meters above ground level (AGL), and each sample day's back trajectories are plotted to
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create a composite back trajectory map. A composite back trajectory map was constructed for
each monitoring site using Geographical Information System (GIS) software. The composite
back trajectory map can be used in the estimation of a 24-hour air shed domain for each site. An
air shed domain is the geographical area surrounding a site from which an air parcel may
typically travel within the 24-hour time frame. Information about the maximum and average
trajectory length may also be provided in reference to the composite back trajectory maps. Note
that the distances provided are straight-line distances, or the length from the site to end point, not
necessarily the length of the actual trajectory. Agencies can use the air shed domain to evaluate
regions where long-range transport may affect their monitoring site.
In addition to the composite back trajectory map, the HYSPLIT model was used to
perform trajectory cluster analysis. This analysis is a grouping technique that allows the model to
create a subset of trajectories or "clusters" that represent trajectories originating from similar
locations. For each monitoring site, data from each sample day's back trajectories were used as
input for the cluster analysis program. The model compares the end points between each
trajectory and calculates a spatial variance. Trajectories that are similar to each other have lower
spatial variances while trajectories that are dissimilar have larger spatial variances. The model
then provides the user with information about total spatial variance (TSV) among the
trajectories, which allows the user to determine how many clusters best represent a given group
of trajectories (Draxler, R.R., et. al., 2009). Similar to the composite map, once the cluster
trajectories for each site were computed, a cluster map was constructed for each monitoring site
using GIS software. Both the direction and the distance from monitoring site are considered in
the clustering process. A minimum of 30 trajectories must be available for the model to run the
cluster analysis. Since four trajectories were computed for each sample day, a minimum of 30
sample days was the criteria used to perform the cluster analysis for this report. The cluster
analysis is useful for scientifically and quantitatively determining where air most often originates
for a given location.
3.5.2.2 Wind Rose Analysis
Wind roses were constructed for each site to help identify the predominant direction from
which the wind blows. A wind rose shows the frequency of wind directions as petals positioned
around a 16-point compass, and uses color or shading to represent wind speeds. Wind roses are
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constructed by uploading hourly NWS surface wind data from the nearest weather station (with
sufficient data) into a wind rose software program, WRPLOT (Lakes, 2011). For each site, three
wind roses were constructed: first, historical data were used to construct a historical wind rose
for up to 10 years prior to sampling; second, 2011 data were used to construct a wind rose
presenting wind data for the entire calendar year; and lastly, a wind rose was constructed to
present wind data for sample days only. In addition to the wind roses, a map showing the
distance between the NWS station used and the monitoring site is presented. This allows for
topographical influences on the wind patterns to potentially be identified.
A wind rose is often used in determining where to install an ambient monitoring site
when trying to capture emissions from an upwind source. A wind rose may also be useful in
determining whether high concentrations correlate with a specific wind direction. While the
composite back trajectory map shows where air parcels originated on a number of days, the wind
rose shows the frequency at which wind speed and direction are measured near the monitoring
site. Thus, the back trajectory analysis focuses on long range transport, while the wind rose
captures day-to-day fluctuations at the surface. Both are used to identify potential meteorological
influences on a monitoring site.
3.5.3 Site-Specific Comparison to Program-level Average Concentrations
To better understand how a site's concentrations compare to the program-level
concentrations, as presented in Tables 4-1 through 4-6 of Section 4.1, the site-specific and
program-level concentrations are presented together graphically for the selected NATTS MQO
Core Analytes listed in Table 3.3. This analysis is an extension of the analysis discussed in
Section 3.4.2 and utilizes box and whisker plots, or simply box plots, to visually show this
comparison. These box plots were created in Microsoft Excel, using the Peltier Box and Whisker
Plot Utility (Peltier, 2012). Note that for sites that sampled SNMOCs, benzene and 1,3-butadiene
are shown only in comparison to those sites sampling SNMOCs as opposed to sites sampling
these pollutants with Method TO-15, to match the program-level averages presented in
Tables 4-1 and 4-2 in Section 4.1.
The box plots used in this analysis overlay the site-specific minimum, annual average,
and maximum concentrations over several program-level statistical metrics. For the program-
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level, the first, second (median), third, and fourth (maximum) quartiles are shown as colored
segments on a "bar" where the color changes indicate the exact numerical value of the quartile.
The thin vertical line represents the program-level average concentration. The site-specific
annual average is shown as a white circle plotted on top of the bar and the horizontal lines
represent the minimum and maximum concentration measured at the site. An example of this
figure is shown in Figure 5-10. Note that the program-level average concentrations shown for
VOCs, SNMOCs, and carbonyl compounds in Tables 4-1 through 4-3 are presented in method-
specific units, but have been converted to a common unit of measurement (|ig/m3) for the
purposes of this analysis. These graphs are presented in Sections 5 through 28, and are grouped
by pollutant within each state section. This allows for both a "site vs. program" comparison, and
an inter-site comparison for sites within a given state.
Table 3-3. NATTS MQO Core Analytes Selected for Comparative Analysis
Pollutant
Benzene
1,3 -Butadiene
Acetaldehyde
Formaldehyde
Benzo(a)pyrene
Naphthalene
Arsenic
Manganese
Lead
Hexavalent Chromium
Class/Method
VOCs/TO-15
Carbonyl
Compounds/TO-llA
PAHs/TO-13A
MetaMO-3.5
Metals/EPA
3.5.4 Site Trends Analysis
Table 2-1 presents current monitoring sites that have participated in the NMP in previous
years. A site-specific trends analysis was conducted for sites with at least 5 consecutive years of
method-specific data analyzed under the NMP. The trends analysis was conducted for the
selected NATTS MQO Core Analytes shown in Table 3-3. Twenty-nine of the 51 sites have
sampled at least one pollutant group long enough for the trends analysis to be conducted. The
approach to this trends analysis is described below and the results are presented in the individual
state sections (Sections 5 through 28).
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The trends figures and analyses are presented as 1-year statistical metrics, which is a
change from previous reports (where 3-year rolling average concentrations were calculated). The
following criteria were used to calculate valid statistical metrics:
Analysis must have been performed under the NMP.
There must be a minimum of at least 5 years of consecutive data.
There must be a minimum of 85 percent completeness for each sampling year, which
corresponds to roughly 51 valid samples or approximately 10 months of sampling
(for a site sampling on a l-in-6 day sampling schedule).
Five individual statistical metrics were used in this analysis and are presented as box and
whisker plots, an example of which can be seen in Figure 5-18. The statistical metrics shown
include the minimum and maximum concentration measured during each year (as shown by the
upper and lower value of the lines extending from the box); the 5th percentile, 50thpercentile (or
median), and 95th percentile (as shown by the y-values corresponding with the bottom, gray line,
or top of the box, respectively); and the average concentration (as denoted by the orange
diamond). Each of the five metrics represents all measurements from that 1-year period.
Data used in this analysis were downloaded from EPA's AQS database (EPA, 2012c),
where non-detects are uploaded into AQS as zeros (EPA, 2009b). Similar to other analyses
presented in this report, zeros representing these non-detects were incorporated into the
statistical calculations. The results from sample days with precision data (duplicates, collocates,
and/or replicates) were averaged together to allow for the determination of a single concentration
per pollutant for each site, reflecting the data treatment described in Section 3.1.
3.5.5 Preliminary Risk-Based Screening and Pollutants of Interest
The preliminary risk-based screening process described in Section 3.2 and applied at the
program-level was also completed for each individual monitoring site to determine site-specific
pollutants of interest. Once these were determined, the time-period averages (quarterly and
annual) described in Section 3.1 were calculated for each site and were used for various risk-
related analyses at the site-specific level, as described below:
Comparison to ATSDR MRLs, as described in Section 3.3, including the emission
tracer analysis described below
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The calculation of cancer risk and noncancer hazard approximations in relation to
cancer and noncancer health effects
Risk-based emissions assessment.
3.5.5.1 Emission Tracer Analysis
The preprocessed daily measurements and time-period average concentrations for each
site-specific pollutant of interest were compared to the ATSDR MRL noncancer health
benchmarks in the same fashion described in Section 3.3. To further this analysis, pollution roses
were created for each of the site-specific pollutants of interest that have preprocessed daily
measurements greater than their respective ATSDR acute MRL health benchmark (where
applicable). This analysis is performed to help identify the geographical area where the
emissions sources of these pollutants may have originated. A pollution rose is a plot of the
ambient concentration versus the wind speed and direction; high concentrations may be shown in
relation to the direction of potential emissions sources.
3.5.5.2 Cancer Risk and Noncancer Hazard Approximations
Risk was further examined by calculating cancer risk and noncancer hazard
approximations for each of the site-specific pollutants of interest. The cancer risk
approximations presented in this report estimate the cancer risk due to exposure at the annual
average concentration over a 70-year period (not the risk resulting from exposure over the time
period covered in this report). A cancer risk approximation less than 1 in-a-million is considered
negligible; a cancer risk greater than 1 in-a-million but less than 100 in-a-million is generally
considered acceptable; and a cancer risk greater than 100 in-a-million is considered significant
(EPA, 2009c). The noncancer hazard approximation is presented as the Noncancer Hazard
Quotient (HQ), which is a unitless value. According to EPA, "If the HQ is calculated to be equal
to or less than 1.0, then no adverse health effects are expected as a result of exposure. If the HQ
is greater than 1.0, then adverse health effects are possible" (EPA, 201 Ib).
The toxicity factors applied to calculate the cancer risk and noncancer hazard
approximations are typically UREs (for cancer) or RfCs (for noncancer), which are developed by
EPA. However, UREs and RfCs are not available for all pollutants. In the absence of EPA
values, toxicity factors developed by agencies with credible methods and that are similar in
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scope and definition were used (EPA, 2012h). Cancer URE and noncancer RfC toxicity factors
can be applied to the annual averages to approximate risk based on ambient monitoring data.
While the cancer risk and noncancer hazard approximations do not incorporate human activity
patterns and therefore do not reflect true human inhalation exposure, they may allow analysts to
further refine their focus by identifying concentrations of specific pollutants that may present
health risks. Cancer UREs and/or noncancer RfCs, site-specific annual averages, and
corresponding annual average-based cancer risk and noncancer hazard approximations are
presented in each state section (Sections 5 through 28).
3.5.5.3 Risk-Based Emissions Assessment
A pollutant emitted in high quantities does not necessarily present a higher risk to human
health than a pollutant emitted in very low quantities. The more toxic the pollutant, the more risk
associated with its emissions in ambient air. The development of various health-based toxicity
factors has allowed analysts to apply weight to the emissions of pollutants based on toxicity
rather than mass emissions. This approach considers both a pollutant's toxicity potential and the
quantity emitted.
This assessment compares county-level emissions to toxicity-weighted emissions based
on the EPA-approved approach described below (EPA, 2007). The 10 pollutants with the highest
total mass emissions and the 10 pollutants with the highest associated toxicity-weighted
emissions for pollutants with cancer and noncancer toxicity factors are presented in each state
section. While the absolute magnitude of the pollutant-specific toxicity-weighted emissions is
not meaningful, the relative magnitude of toxicity-weighted emissions is useful in identifying the
order of potential priority for air quality managers. Higher values suggest greater priority;
however, even the highest values may not reflect potential cancer effects greater than the level of
concern (100 in-a-million) or potential noncancer effects above the level of concern
(e.g., HQ = 1.0). The pollutants exhibiting the 10 highest annual average-based risk
approximations for cancer and noncancer effects are also presented in each state section. The
results of this data analysis may help state, local, and tribal agencies better understand which
pollutants emitted, from a toxicity basis, are of the greatest concern.
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The toxicity-weighted emissions approach consists of the following steps:
1. Obtain HAP emissions data for all anthropogenic sectors from the NEI. For point
sources, sum the process-level emissions to the county-level.
2. Apply the mass extraction speciation profiles to extract metal and cyanide mass. The
only exception is for two chromium species: chromium and chromium compounds.
3. For chromium and chromium compounds, trivalent chromium (non-toxic) must be
separated from hexavalent chromium (toxic). To do this, apply the chromium
speciation profile to extract the hexavalent chromium mass by industry group.
4. Apply weight to the emissions derived from the steps above based on their toxicity.
The results of the toxicity-weighting process are unitless.
a. To apply weight based on cancer toxicity, multiply the emissions of each
pollutant by its cancer URE.
b. To apply weight based on noncancer toxicity, divide the emissions of each
pollutant by its noncancer RfC.
The PAHs measured using Method TO-13A are a sub-group of Poly cyclic Organic
Matter (POM). Because these compounds are often not speciated into individual compounds in
the NEI, the PAHs are grouped into POM Groups in order to assess risk attributable to these
pollutants (EPA, 201 Ic). Thus, emissions data and toxicity-weighted emissions for PAHs are
presented by POM Groups for this analysis. Table 3-4 presents the 22 PAHs measured by
Method TO-13A and their associated POM Groups. The POM groups are sub-grouped in
Table 3-4 because toxicity research has led to the refining of UREs for certain PAHs (EPA,
2012h). Note that naphthalene emissions are reported to the NEI individually; therefore,
naphthalene is not included in one of the POM Groups. Also note that four pollutants analyzed
by Method TO-13A and listed in Table 3-4 do not have assigned POM Groups.
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Table 3-4. POM Groups for PAHs
Pollutant
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Coronene
Cyclopenta[cd]pyrene
Dibenz(a,h)anthracene
Fluoranthene
Fluorene
9-Fluorenone
Indeno( 1 ,2,3 -cd)pyrene
Naphthalene*
Perylene
Phenanthrene
Pyrene
Retene
POM Group
Group 2
Group 2
Group 2
POM
Subgroup
Group 2b
Group 2b
Group 2d
Group 6
Group 5
GroupSa
Group 6
Group 2
Group 2
Group 2b
Group 2b
Group 6
Group 7
NA
NA
Group 5
Group 2
Group 2
GroupSb
Group 2b
Group 2b
NA
Group 6
NA
Group 2
Group 2
Group 2
Group 2b
Group 2d
Group 2d
NA
* Naphthalene emissions are reported to the NEI individually;
therefore, naphthalene is not included in one of the POM Groups.
NA = no POM Group assigned.
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4.0 Summary of the 2011 National Monitoring Programs Data
This section summarizes the results of the data analyses performed on the NMP dataset,
as described in Section 3.
4.1 Statistical Results
This section examines the following statistical parameters for the target pollutants of each
analytical method: 1) detection rates, 2) concentration ranges and data distribution, and 3) central
tendency statistics. Tables 4-1 through 4-6 present statistical summaries for the target pollutants
and Sections 4.1.1 through 4.1.3 review the basic findings of these statistical calculations.
4.1.1 Target Pollutant Detection Rates
There is an experimentally determined MDL for every target pollutant, as described in
Section 2.2. Quantification below the MDL is possible, although the measurement's reliability is
lower. If a concentration does not exceed the MDL, it does not mean that the pollutant is not
present in the air. If the instrument does not generate a numerical concentration, the
measurement is marked as "ND," or "non-detect." As explained in Section 2.2, data analysts
should exercise caution when interpreting monitoring data with a high percentage of reported
concentrations at levels near or below the corresponding MDLs. A thorough review of the
number of measured detections, the number of non-detects, and the total number of samples is
beneficial to understanding the representativeness of the interpretations made.
Tables 4-1 through 4-6 summarize the number of times the target pollutants were
detected out of the number of valid samples collected and analyzed. Approximately 54 percent of
the reported measurements (based on the preprocessed daily measurements) were above the
MDLs across the program. The following list provides the percentage of measurements that were
above the MDLs for each method:
40.7 percent for VOCs
51.1 percent for SNMOCs
81.5 percent for carbonyl compounds
63.0 percent for PAHs
4-1
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82.6 percent for metals
79.4 percent for hexavalent chromium samples.
Some pollutants were always detected while others were infrequently detected or not
detected at all. Similar to previous years' reports, acetaldehyde, formaldehyde, and acetone had
the greatest number of measured detections (1,594), using the preprocessed daily measurements.
These pollutants were reported in every valid carbonyl compound sample collected (1,594).
Acetylene, benzene, chloromethane, dichlorodifluoromethane, propylene, toluene,
trichlorofluoromethane, and trichlorotrifluoroethane were detected in every valid VOC sample
collected (1,281). Eight pollutants, including acetylene, ethylene, ethane, and toluene, were
detected in every valid SNMOC sample collected (441). Naphthalene, phenanthrene,
fluoranthene, and pyrene were detected in every valid PAH sample collected (1,382). Cadmium,
lead, manganese, and nickel were detected in every valid metal sample collected (834).
Hexavalent chromium was detected in 1,068 samples (out of 1,328 samples).
Although BTUT and NBIL have the greatest number of measured detections (7,321 for
BTUT and 6,995 for NBIL), they were also the only two sites that collected samples for all six
analytical methods/pollutant groups. However, the detection rates for these sites (66 and
68 percent, respectively) were not as high as other sites. Detection rates for sites that sampled
suites of pollutants that are frequently detected tended to be higher (refer to the list of method-
specific percentages of measurements above the MDL listed above). For example, metals were
rarely reported as non-detects. As a result, sites that sampled only metals (such as PAFL) would
be expected to have higher detection rates. PAFL's detection rate is 99 percent. Conversely,
VOCs had the lowest percentage of concentrations greater than the MDLs (40.7 percent). A site
measuring only VOCs would be expected to have lower detection rates, such as SPAZ
(48.3 percent).
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Table 4-1. Statistical Summaries of the VOC Concentrations
Pollutant
Acetonitrile
Acetylene
Acrolein
Acrylonitrile3
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1 ,2-Dibromoethane
m -Dichlorobenzene
o-Dichlorobenzene
^-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
#of
Measured
Detections1
1,275
1,281
1,254
300
33
1,281
o
6
61
69
737
966
1,219
1,279
20
203
756
1,281
9
1
299
31
88
108
736
1,281
5
#
of Non-
Detects1
6
0
27
924
1,248
0
1,278
1,220
1,212
544
315
62
2
1,261
1,078
525
0
1,272
1,280
982
1,250
1,193
1,173
545
0
1,276
Minimum2
(ppbv)
0.045
0.082
0.078
0.013
0.004
0.053
0.009
0.012
0.004
0.007
0.007
0.004
0.006
0.007
0.006
0.003
0.133
0.008
Maximum
(ppbv)
1,030
101
11.0
0.778
0.010
7.42
0.049
3.05
0.062
0.437
4.29
22.8
0.260
0.084
8.18
6.72
2.53
0.124
0.016
0.002
0.005
0.004
0.002
0.003
0.114
0.008
1.13
0.022
0.329
0.083
0.469
1.23
0.021
Arithmetic
Mean
(ppbv)
14.7
0.935
0.489
0.039
0.000
0.305
0.0001
0.021
0.001
0.010
0.043
0.925
0.096
0.000
0.011
0.079
0.611
0.000
Median
(ppbv)
0.392
0.598
0.370
0
0
0.218
0
0
0
0.010
0.028
0.033
0.098
0
0
0.018
0.600
0
Mode
(ppbv)
0.206
1.09
0
0
0
0.149
0
0
0
0
0
0
0.098
0
0
0
0.610
0
First
Quartile
(ppbv)
0.200
0.387
0.215
0
0
0.158
0
0
0
0
0.008
0.013
0.085
0
0
0
0.543
0
Third
Quartile
(ppbv)
1.91
0.970
0.597
0
0
0.325
0
0
0
0.014
0.050
0.425
0.109
0
0
0.030
0.663
0
Standard
Deviation
(ppbv)
67.0
3.31
0.526
0.103
0.001
0.359
0.001
0.163
0.004
0.019
0.133
2.60
0.022
0.003
0.229
0.427
0.114
0.005
Coefficient
of
Variation
4.55
3.54
1.08
2.62
6.36
1.18
26.4
7.90
5.34
1.99
3.07
2.81
0.234
10.4
21.0
5.38
0.186
18.6
NA
0.008
0.000
0.001
0.001
0.013
0.554
0.0001
0
0
0
0
0.008
0.548
0
0
0
0
0
0
0.544
0
0
0
0
0
0
0.526
0
0
0
0
0
0.017
0.578
0
0.055
0.002
0.012
0.003
0.024
0.059
0.001
6.52
6.82
9.12
4.64
1.86
0.106
17.0
2 Excludes zeros for non-detects
3 Because S4MO invalidated all acrylonitrile data for 2011, the number of measured detections plus the number of non-detects does not equal the total number of VOC samples
collected (1,281).
NA = Not applicable for these parameters
-------
Table 4-1. Statistical Summaries of the VOC Concentrations (Continued)
Pollutant
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
c/'s-l,2-Dichloroethylene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1,2-Dichloropropane
cis- 1 , 3 -Dichloropropene
trans- 1 ,3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Aery late
Ethyl fert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
Methyl fer/-Butyl Ether
w-Octane
Propylene
Styrene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1, 1,2-Trichloroethane
#of
Measured
Detections1
320
22
0
14
1,264
1
11
6
1,241
4
8
1,277
113
1,280
1,202
54
37
1,241
1,281
1,219
55
958
1,281
48
1,096
8
#
of Non-
Detects1
961
1,259
1,281
1,267
17
1,280
1,270
1,275
40
1,277
1,273
4
1,168
1
79
1,227
1,244
40
0
62
1,226
323
0
1,233
185
1,273
Minimum2
(ppbv)
0.011
0.005
Maximum
(ppbv)
0.174
0.018
Arithmetic
Mean
(ppbv)
0.006
0.0001
Median
(ppbv)
0
0
Mode
(ppbv)
0
0
First
Quartile
(ppbv)
0
0
Third
Quartile
(ppbv)
0
0
Standard
Deviation
(ppbv)
0.012
0.001
Coefficient
of
Variation
2.04
8.14
Not Detected
0.006
0.040
0.050
349
0.012
0.007
0.011
0.004
0.020
0.005
0.004
0.003
0.059
0.006
0.009
0.005
0.008
0.057
0.006
0.004
0.004
0.023
0.004
0.002
0.008
0.088
0.057
0.078
0.078
0.016
2.65
0.064
34.3
2.43
0.34
0.274
2.62
34.1
3.06
0.048
1.27
14.9
0.083
0.081
0.017
0.0002
1.01
0
0.128
0
0
0
0.087
0
0.230
0.002
12.6
11.8
12.5
NA
0.0002
0.0001
0.019
0.0001
0.0001
0.093
0.001
0.541
0.043
0.002
0.001
0.061
0.704
0.059
0.0005
0.023
0.586
0.001
0.010
0.000
0
0
0.018
0
0
0.064
0
0.430
0.034
0
0
0.041
0.374
0.034
0
0.014
0.339
0
0.010
0
0
0
0.017
0
0
0.038
0
0.474
0
0
0
0
0.348
0
0
0
0.288
0
0
0
0
0
0.016
0
0
0.041
0
0.285
0.022
0
0
0.027
0.265
0.023
0
0
0.187
0
0.008
0
0
0
0.020
0
0
0.101
0
0.643
0.052
0
0
0.065
0.558
0.049
0
0.027
0.645
0
0.012
0
0.003
0.002
0.008
0.003
0.001
0.123
0.004
1.00
0.074
0.014
0.012
0.100
1.85
0.156
0.003
0.048
0.959
0.003
0.006
0.001
14.6
17.9
0.440
20.7
13.2
1.32
4.12
1.85
1.72
7.34
11.4
1.64
2.63
2.65
5.50
2.06
1.64
6.82
0.570
13.0
2 Excludes zeros for non-detects
3 Because S4MO invalidated all acrylonitrile data for 2011, the number of measured detections plus the number of non-detects does not equal the total number of VOC samples
collected (1,281).
NA = Not applicable for these parameters
-------
Table 4-1. Statistical Summaries of the VOC Concentrations (Continued)
Pollutant
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 , 3 , 5-Trimethylbenzene
Vinyl chloride
m,p-Xylene
o-Xylene
#of
Measured
Detections1
251
1,281
1,281
1,275
1,226
82
1,273
1,267
#
of Non-
Detects1
1,030
0
0
6
55
1,199
8
14
Minimum2
(ppbv)
0.004
0.051
0.023
0.005
0.004
0.003
0.009
0.005
Maximum
(ppbv)
1.56
1.41
0.180
1.05
0.386
0.033
6.08
1.99
Arithmetic
Mean
(ppbv)
0.009
0.280
0.097
0.088
0.032
0.001
0.243
0.095
Median
(ppbv)
0
0.270
0.096
0.061
0.024
0
0.148
0.062
Mode
(ppbv)
0
0.262
0.096
0.033
0
0
0.033
0.023
First
Quartile
(ppbv)
0
0.255
0.089
0.039
0.016
0
0.078
0.036
Third
Quartile
(ppbv)
0
0.290
0.104
0.103
0.037
0
0.267
0.105
Standard
Deviation
(ppbv)
0.067
0.061
0.012
0.095
0.031
0.002
0.386
0.127
Coefficient
of
Variation
7.57
0.219
0.129
1.07
0.937
6.21
1.11
0.997
1 Out of 1,281 valid samples
2 Excludes zeros for non-detects
3 Because S4MO invalidated all acrylonitrile data for 20 1 1,
collected (1,281).
NA = Not applicable for these parameters
the number of measured detections plus the number of non-detects does not equal the total number of VOC samples
-------
Table 4-2. Statistical Summaries of the SNMOC Concentrations
Pollutant
Acetylene
Benzene
1,3 -Butadiene
w-Butane
c/s-2-Butene
/raซs-2-Butene
Cyclohexane
Cyclopentane
Cyclopentene
w-Decane
1-Decene
Tw-Diethylbenzene
ฃ>-Diethylbenzene
2,2-Dimethylbutane
2,3 -Dimethylbutane
2,3 -Dimethylpentane
2,4-Dimethylpentane
w-Dodecane
1-Dodecene
Ethane
2-Ethyl-l-butene
Ethylbenzene
Ethylene
/w-Ethyltoluene
o-Ethyltoluene
ฃ>-Ethyltoluene
w-Heptane
#of
Measured
Detections1
441
436
151
361
325
337
425
414
117
405
5
401
357
424
351
423
423
427
355
441
2
433
441
403
319
403
435
#
of Non-
Detects1
0
5
290
80
116
104
16
27
324
36
436
40
84
17
90
18
18
14
86
0
439
8
0
38
122
38
6
Minimum2
(ppbC)
0.271
0.241
0.041
0.339
0.048
0.066
0.101
0.076
0.077
0.073
0.096
0.075
0.077
0.088
0.101
0.107
0.080
0.073
0.071
1.59
0.241
0.086
0.717
0.082
0.086
0.062
0.079
Maximum
(ppbC)
237
12.9
4.24
81.9
2.36
5.54
16.9
21.0
8.21
9.12
4.27
2.38
1.82
2.93
3.86
4.07
2.28
6.60
8.57
1,390
0.557
4.05
674
2.68
2.71
1.99
11.9
Arithmetic
Mean
(ppbC)
2.25
1.65
0.120
11.7
0.197
0.276
1.92
0.615
0.134
0.571
0.013
0.404
0.269
0.555
0.730
0.611
0.406
0.519
0.302
54.9
0.002
0.531
4.81
0.328
0.222
0.246
1.65
Median
(ppbC)
1.12
1.13
0
5.70
0.146
0.177
0.954
0.402
0
0.383
0
0.350
0.214
0.421
0.455
0.478
0.324
0.437
0.201
26.2
0
0.341
2.09
0.266
0.182
0.214
0.924
Mode
(ppbC)
1.10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
100
0
0
1.83
0
0
0
0
First
Quartile
(ppbC)
0.733
0.704
0
1.53
0
0.092
0.240
0.241
0
0.170
0
0.239
0.118
0.262
0.165
0.303
0.197
0.322
0.112
5.89
0
0.232
1.57
0.162
0
0.151
0.261
Third
Quartile
(ppbC)
1.70
2.25
0.184
16.0
0.230
0.297
2.81
0.723
0.086
0.668
0
0.522
0.356
0.709
1.04
0.803
0.539
0.628
0.363
69.4
0
0.636
3
0.435
0.320
0.310
2.44
Standard
Deviation
(ppbC)
12.4
1.42
0.285
15.1
0.268
0.423
2.41
1.14
0.488
0.801
0.207
0.290
0.272
0.453
0.802
0.482
0.311
0.464
0.511
97.1
0.029
0.509
35.3
0.275
0.272
0.187
1.88
Coefficient
of
Variation
5.51
0.860
2.38
.29
.36
.53
.25
.85
3.64
1.40
16.0
0.717
1.01
0.815
1.10
0.788
0.765
0.895
1.69
1.77
15.9
0.959
7.33
0.841
1.23
0.762
1.14
1 Out of 441 valid samples
2 Excludes zeros for non-detects
NA = Not applicable for these parameters
-------
Table 4-2. Statistical Summaries of the SNMOC Concentrations (Continued)
Pollutant
1-Heptene
w-Hexane
1-Hexene
c/s-2-Hexene
trans-2-Rexene
Isobutane
Isobutene/ 1 -Butene
Isopentane
Isoprene
Isopropylbenzene
2-Methyl-l-butene
3 -Methyl- 1 -butene
2-Methy 1- 1 -pentene
4-Methy 1- 1 -pentene
2-Methyl-2 -butene
Methylcyclohexane
Methylcyclopentane
2-Methy Iheptane
3-Methylheptane
2-Methy Ihexane
3 -Methy Ihexane
2-Methy Ipentane
3-Methylpentane
w-Nonane
1-Nonene
w-Octane
1-Octene
#of
Measured
Detections1
308
439
357
54
25
440
181
418
370
273
249
6
12
14
287
418
438
349
357
427
411
441
441
403
135
423
164
#
of Non-
Detects1
133
2
84
387
416
1
260
23
71
168
192
435
429
427
154
23
3
92
84
14
30
0
0
38
306
18
277
Minimum2
(ppbC)
0.050
0.137
0.086
0.076
0.064
0.208
0.107
0.729
0.076
0.081
0.096
0.161
0.062
0.116
0.087
0.101
0.104
0.059
0.054
0.168
0.135
0.243
0.099
0.066
0.054
0.090
0.057
Maximum
(ppbC)
3.87
67.9
0.566
0.404
0.543
129
13.5
110
7.20
0.400
2.84
2.25
0.382
0.358
7.81
33.1
21.5
3.15
2.43
6.76
6.66
28.3
22.1
11.0
3.60
8.94
0.727
Arithmetic
Mean
(ppbC)
0.436
3.48
0.190
0.020
0.010
11.8
0.889
14.0
0.406
0.094
0.220
0.010
0.005
0.006
0.262
3.58
1.85
0.482
0.386
1.31
1.19
3.46
1.98
0.668
0.090
1.15
0.078
Median
(ppbC)
0.202
1.72
0.211
0
0
5.73
0
10.2
0.195
0.116
0.163
0
0
0
0.191
1.44
1.04
0.290
0.251
0.930
0.839
2.24
1.19
0.401
0
0.643
0
Mode
(ppbC)
0
1.01
0
0
0
1.14
0
0
0
0
0
0
0
0
0
0
2.76
0
0
0
0
1.16
2.49
0
0
0
0
First
Quartile
(ppbC)
0
0.599
0.137
0
0
1.50
0
4.36
0.127
0
0
0
0
0
0
0.266
0.384
0.096
0.108
0.549
0.390
0.967
0.529
0.171
0
0.241
0
Third
Quartile
(ppbC)
0.671
4.29
0.263
0
0
15.7
1.52
18.9
0.362
0.155
0.312
0
0
0
0.326
5.42
2.47
0.761
0.576
1.82
1.71
4.48
2.58
0.827
0.139
1.60
0.143
Standard
Deviation
(ppbC)
0.562
5.44
0.115
0.061
0.051
15.5
1.57
14.4
0.671
0.081
0.318
0.121
0.033
0.035
0.505
4.76
2.33
0.538
0.406
1.09
1.11
3.70
2.34
0.938
0.248
1.30
0.121
Coefficient
of
Variation
1.29
1.56
0.604
3.01
5.02
1.31
1.77
1.03
1.65
0.863
1.45
11.7
7.02
5.92
1.93
1.33
1.26
1.11
1.05
0.834
0.933
1.07
1.18
1.40
2.75
1.13
1.56
1 Out of 441 valid samples
2 Excludes zeros for non-detects
NA = Not applicable for these parameters
-------
Table 4-2. Statistical Summaries of the SNMOC Concentrations (Continued)
Pollutant
w-Pentane
1-Pentene
c/s-2-Pentene
/raซs-2-Pentene
a-Pinene
6-Pinene
Propane
w-Propylbenzene
Propylene
Propyne
Styrene
Toluene
w-Tridecane
1-Tridecene
1 ,2,3 -Trimethylbenzene
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
2,2,3 -Trimethylpentane
2,2,4-Trimethylpentane
2,3 ,4-Trimethylpentane
w-Undecane
1-Undecene
7w-Xylene/ฃ>-Xylene
o-Xylene
SNMOC (Sum of Knowns)
Sum of Unknowns
TNMOC
#of
Measured
Detections1
441
422
266
363
122
46
441
347
438
9
83
441
41
14
359
430
254
108
332
383
401
57
246
426
441
441
441
#
of Non-
Detects1
0
19
175
78
319
395
0
94
o
6
432
358
0
400
427
82
11
187
333
109
58
40
384
195
15
NA
NA
NA
Minimum2
(ppbC)
0.160
0.075
0.062
0.064
0.071
0.094
1.41
0.075
0.294
0.101
0.052
0.248
0.061
0.073
0.074
0.108
0.059
0.074
0.084
0.056
0.078
0.053
0.076
0.097
15.9
11.2
30.1
Maximum
(ppbC)
199
17.2
121
2.63
1.70
2.00
376
1.24
46.4
0.225
5.06
174
2.45
0.377
1.33
10.2
2.01
0.707
4.26
1.48
13.1
2.72
13.7
4.97
2,740
5,510
5,660
Arithmetic
Mean
(ppbC)
7.88
0.425
0.735
0.209
0.106
0.067
34.5
0.155
1.19
0.003
0.104
4.60
0.024
0.005
0.166
0.557
0.210
0.062
0.404
0.212
0.429
0.055
1.13
0.539
192
88.6
280
Median
(ppbC)
3.76
0.233
0.103
0.158
0
0
18.0
0.148
0.836
0
0
2.29
0
0
0.155
0.417
0.134
0
0.235
0.174
0.287
0
0.360
0.396
116
47.0
195
Mode
(ppbC)
1.94
0
0
0
0
0
126
0
1.03
0
0
2.72
0
0
0
0
0
0
0
0
0
0
0
0
250
29.5
245
First
Quartile
(ppbC)
1.5
0.179
0
0.107
0
0
6.15
0.103
0.640
0
0
1.14
0
0
0.108
0.278
0
0
0.086
0.120
0.150
0
0
0.231
49.1
28.5
101
Third
Quartile
(ppbC)
8.85
0.339
0.154
0.253
0.142
0
43.6
0.207
1.16
0
0
4.24
0
0
0.215
0.661
0.324
0
0.503
0.249
0.493
0
1.75
0.649
250
76.4
328
Standard
Deviation
(ppbC)
14.1
1.12
7.95
0.255
0.220
0.237
43.2
0.133
2.51
0.024
0.424
14.2
0.141
0.028
0.140
0.653
0.267
0.124
0.549
0.192
0.765
0.258
1.78
0.555
234
281
366
Coefficient
of
Variation
1.79
2.62
10.8
1.22
2.08
3.55
1.25
0.863
2.11
7.18
4.07
3.08
5.85
6.24
0.844
1.17
1.27
2.00
1.36
0.909
1.78
4.70
1.57
1.03
1.22
3.18
1.31
1 Out of 441 valid samples
2 Excludes zeros for non-detects
NA = Not applicable for these parameters
-------
Table 4-3. Statistical Summaries of the Carbonyl Compound Concentrations
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes
Valeraldehyde
#of
Measured
Detections1
1,594
1,594
1,572
1,591
1,570
0
1,594
1,562
3
1,588
1,364
1,563
#
of Non-
Detects1
0
0
22
3
24
1,594
0
32
1,591
6
230
31
Minimum2
(ppbv)
0.023
0.031
0.004
0.008
0.005
Maximum
(ppbv)
8.05
6.48
0.359
0.924
2.19
Arithmetic
Mean
(ppbv)
1.11
1.08
0.032
0.103
0.108
Median
(ppbv)
0.928
0.881
0.024
0.084
0.040
Mode
(ppbv)
1.07
1.21
0.017
0.065
0.016
First
Quartile
(ppbv)
0.636
0.580
0.016
0.058
0.022
Third
Quartile
(ppbv)
1.38
1.37
0.035
0.121
0.123
Standard
Deviation
(ppbv)
0.719
0.771
0.030
0.079
0.163
Coefficient
of
Variation
0.647
0.716
0.956
0.770
1.51
Not Detected
0.026
0.004
0.014
0.008
0.005
0.005
22.5
1.29
0.028
0.604
0.256
0.550
2.33
0.039
0.00004
0.132
0.030
0.030
1.82
0.024
0
0.110
0.024
0.022
1.79
0.012
0
0.081
0
0.011
1.22
0.015
0
0.078
0.014
0.014
2.76
0.039
0
0.165
0.038
0.035
1.89
0.086
0.001
0.084
0.029
0.041
0.813
2.20
23.9
0.633
0.947
1.35
2 Excludes zeros for non-detects
-------
Table 4-4. Statistical Summaries of the PAH Concentrations
Pollutant
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Coronene
Cyclopenta[cd]pyrene
Dibenz(a,h)anthracene
Fluoranthene
Fluorene
9-Fluorenone
Indeno( 1 ,2,3 -cd)pyrene
Naphthalene
Perylene
Phenanthrene
Pyrene
Retene
#of
Measured
Detections1
1,366
634
1,015
968
844
1,275
1,131
1,225
817
1,321
852
250
287
1,382
1,376
1,379
1,074
1,382
423
1,382
1,382
1,363
#
of Non-
Detects1
16
748
367
414
538
107
251
157
565
61
530
1,132
1,095
0
6
3
308
0
959
0
0
19
Minimum2
(ng/m3)
0.0793
0.0428
0.0229
0.015
0.0175
0.0194
0.0147
0.0115
0.00906
0.0204
0.0127
0.0147
0.0158
0.0925
0.365
0.101
0.0175
2.27
0.00889
0.387
0.0408
0.0204
Maximum
(ng/m3)
111
17.6
17.1
2.4
1.99
2.80
1.87
1.55
0.861
3.04
0.705
1.13
0.276
39.5
70.5
15.4
1.34
779
0.398
178
19.0
10.6
Arithmetic
Mean
(ng/m3)
4.64
0.666
0.369
0.088
0.084
0.219
0.112
0.126
0.056
0.218
0.051
0.023
0.009
2.42
4.98
1.46
0.110
81.7
0.016
9.92
1.40
0.410
Median
(ng/m3)
2.16
0
0.171
0.043
0.038
0.117
0.064
0.069
0.030
0.134
0.030
0
0
1.27
3.03
1.03
0.061
62.8
0
5.43
0.770
0.203
Mode
(ng/m3)
0
0
0
0
0
0
0
0
0
0
0
0
0
1.51
1.91
1.04
0
102
0
11
1.29
0
First
Quartile
(ng/m3)
0.986
0
0
0
0
0.054
0.030
0.034
0
0.070
0
0
0
0.690
1.69
0.589
0.025
32.8
0
2.87
0.419
0.117
Third
Quartile
(ng/m3)
4.55
0.587
0.411
0.111
0.109
0.276
0.145
0.150
0.076
0.293
0.061
0
0
2.51
5.16
1.77
0.138
108
0.029
10.1
1.47
0.410
Standard
Deviation
(ng/m3)
8.09
1.54
0.826
0.158
0.149
0.284
0.145
0.168
0.086
0.252
0.079
0.080
0.023
3.76
6.98
1.49
0.150
73.3
0.033
15.8
1.95
0.662
Coefficient
of
Variation
1.74
2.31
2.24
1.80
1.76
1.30
1.29
1.33
1.53
1.15
1.55
3.50
2.47
1.55
1.40
1.02
1.37
0.898
2.01
1.59
1.39
1.61
1 Out of 1,382 valid samples
2 Excludes zeros for non-detects
-------
Table 4-5. Statistical Summaries of the Metals Concentrations
Pollutant
Antimony (PM10)
Arsenic (PM10)
Beryllium (PM10)
Cadmium (PM10)
Chromium (PM10)
Cobalt (PM10)
Lead (PM10)
Manganese (PM10)
Mercury (PM10)
Nickel (PM10)
Selenium (PM10)
Antimony (TSP)
Arsenic (TSP)
Beryllium (TSP)
Cadmium (TSP)
Chromium (TSP)
Cobalt (TSP)
Lead (TSP)
Manganese (TSP)
Mercury (TSP)
Nickel (TSP)
Selenium (TSP)
#of
Measured
Detections1'2
546
541
517
547
526
536
547
547
516
547
490
287
287
287
287
287
287
287
287
287
287
287
#
of Non-
Detects1'2
1
6
30
0
21
11
0
0
31
0
57
0
0
0
0
0
0
0
0
0
0
0
Minimum3
(ng/m3)
0.020
0.004
0.0003
0.006
0.004
0.002
0.320
0.403
0.0005
0.073
0.0001
0.063
0.099
0.003
0.025
0.850
0.065
0.571
2.07
0.005
0.271
0.052
Maximum
(ng/m3)
8.87
4.27
0.27
2.23
11
2.96
30.9
395
0.526
7.97
3.24
4.12
1.76
0.108
1.50
9.06
12.3
19.0
104
0.089
5.44
2.57
Arithmetic
Mean
(ng/m3)
1.27
0.587
0.012
0.155
2.68
0.179
3.82
8.81
0.019
1.27
0.440
0.565
0.559
0.022
0.185
1.85
0.708
3.70
17.8
0.013
1.20
0.715
Median
(ng/m3)
0.830
0.436
0.006
0.083
2.49
0.095
2.50
4.48
0.010
0.980
0.300
0.432
0.519
0.018
0.145
1.70
0.370
3.12
14.4
0.012
1.01
0.690
Mode
(ng/m3)
0.190
0.090
0.002
0.040
0
0.040
2.47
13.8
0.01
1.18
0
0.395
0.247
0.009
0.131
1.45
0.368
2.30
21.8
0.012
1.28
1.01
First
Quartile
(ng/m3)
0.478
0.258
0.002
0.050
1.89
0.050
1.57
2.36
0.007
0.629
0.140
0.289
0.349
0.010
0.090
1.43
0.227
2.25
9.32
0.009
0.690
0.399
Third
Quartile
(ng/m3)
1.43
0.761
0.010
0.153
3.25
0.180
4.42
9.86
0.020
1.43
0.540
0.696
0.704
0.029
0.218
2.09
0.663
4.36
23.1
0.016
1.50
0.951
Standard
Deviation
(ng/m3)
1.44
0.525
0.028
0.226
1.44
0.303
4.00
20.6
0.032
1.13
0.488
0.489
0.288
0.016
0.175
0.719
1.30
2.41
12.8
0.007
0.706
0.396
Coefficient
of
Variation
1.13
0.894
2.25
1.46
0.536
1.69
1.05
2.34
1.70
0.890
1.11
0.865
0.515
0.723
0.944
0.389
1.83
0.652
0.719
0.530
0.589
0.554
1 For PM10, out of 548 valid samples
2 For TSP, out of 287 valid samples
3 Excludes zeros for non-detects
-------
Table 4-6. Statistical Summary of the Hexavalent Chromium Concentrations
Pollutant
Hexavalent Chromium
#of
Measured
Detections1
1,068
#
of Non-
Detects1
260
Minimum2
(ng/m3)
0.001
Maximum
(ng/m3)
0.268
Arithmetic
Mean
(ng/m3)
0.024
Median
(ng/m3)
0.018
Mode
(ng/m3)
0
First
Quartile
(ng/m3)
0.009
Third
Quartile
(ng/m3)
0.031
Standard
Deviation
(ng/m3)
0.026
Coefficient
of
Variation
1.08
1 Out of 1,328 valid samples
2 Excludes zeros for non-detects
to
-------
4.1.2 Concentration Range and Data Distribution
The concentrations measured during the 2011 NMP show a wide range of variability. The
minimum and maximum concentration measured (excluding zeros substituted for non-detects)
for each target pollutant are presented in Tables 4-1 through 4-6 (in respective pollutant group
units). Some pollutants, such as acetonitrile, had a wide range of concentrations measured, while
other pollutants, such as dichlorotetrafluoroethane, did not, even though they were both detected
frequently. The pollutant for each method-specific pollutant group with the largest range in
measured concentrations is as follows:
For VOCs, acetonitrile (0.045 ppbv to 1,030 ppbv)
For SNMOCs, ethane (1.59 ppbC to 1,390 ppbC)
For carbonyl compounds, formaldehyde (0.026 ppbv to 22.5 ppbv)
For PAHs, naphthalene (2.27 ng/m3 to 779 ng/m3)
For metals, both size fractions, manganese (0.403 ng/m3 to 395 ng/m3 for PMio and
2.07 ng/m3 to 104 ng/m3 for TSP)
For hexavalent chromium, 0.001 ng/m3 to 0.268 ng/m3.
4.1.3 Central Tendency
In addition to the number of measured detections and the concentration ranges,
Tables 4-1 through 4-6 also present a number of central tendency and data distribution statistics
(arithmetic mean, median, mode, first and third quartiles, standard deviation, and coefficient of
variation) for each of the pollutants sampled during the 2011 NMP in respective pollutant group
units. A multitude of observations can be made from these tables. The pollutants with the three
highest average concentrations, by mass, for each pollutant group are provided below, with
respective confidence intervals, although the 95 percent confidence interval is not provided in
the table.
The top three VOCs by average mass concentration, as presented in Table 4-1, are:
acetonitrile (14.7 ฑ 3.67 ppbv)
dichloromethane (1.01 ฑ 0.693 ppbv)
acetylene (0.934 ฑ0.182 ppbv).
4-13
-------
The top three SNMOCs by average mass concentration, as presented in Table 4-2, are:
ethane (54.9 ฑ 9.09 ppbC)
propane (34.5 ฑ4.04 ppbC)
isopentane (14.0 ฑ 1.34 ppbC).
The top three carbonyl compounds by average mass concentration, as presented in
Table 4-3, are:
formaldehyde (2.33 ฑ 0.09 ppbv)
acetaldehyde (1.11 ฑ 0.04 ppbv)
acetone (1.08 ฑ 0.04 ppbv).
The top three PAHs by average mass concentration, as presented in Tables 4-4, are:
naphthalene (81.7 ฑ3.87 ng/m3)
phenanthrene (9.92 ฑ 0.83 ng/m3)
fluorene (4.98 ฑ 0.37 ng/m3).
The top three metals by average mass concentration for both PMio and TSP fractions, as
presented in Table 4-5, are;
manganese (PMio = 8.81 ฑ 1.73 ng/m3, TSP = 17.80 ฑ 1.49 ng/m3)
lead (PMio = 3.82 ฑ 0.34 ng/m3, TSP = 3.70 ฑ 0.28 ng/m3)
total chromium (PMW = 2.68 ฑ 0.12 ng/m3, TSP = 1.85 ฑ 0.08 ng/m3).
The average mass concentration of hexavalent chromium, as presented in Table 4-6, is
0.024 ฑ0.001 ng/m3.
Appendices J through O present similar statistical calculations on a site-specific basis.
4-14
-------
4.2 Preliminary Risk-Based Screening and Pollutants of Interest
Based on the preliminary risk-based screening process described in Section 3.2,
Table 4-7 identifies the pollutants that failed at least one screen; summarizes each pollutant's
total number of measured detections, percentage of screens failed, and cumulative percentage of
failed screens; and highlights those pollutants contributing to the top 95 percent of failed screens
(shaded in gray) and thereby designated as program-wide pollutants of interest.
The results in Table 4-7 are listed in descending order by number of screens failed.
Table 4-7 shows that formaldehyde failed the highest number of screens (1,592), although
acetaldehyde and benzene were not far behind (1,570 and 1,488, respectively). These three
pollutants were also among those with the highest number of measured detections. Conversely,
four pollutants (chloroprene, c/s-l,3-dichloropropene, tetrachloroethylene, and
frvms-l^-dichloropropene) failed only one screen each. The number of measured detections for
these four pollutants varied significantly. Tetrachloroethylene was detected in 958 samples while
chloroprene was detected only once (both out of 1,281 valid samples).
While seven pollutants exhibited a failure rate of 100 percent, most of them were
infrequently detected. Of these seven, benzene was detected in all 1,488 samples (both SNMOC
and Method TO-15), while the other pollutants were detected less frequently. Thus, the number
of failed screens, the number of measured detections, and the failure rate must all be considered
when reviewing the results of the preliminary risk-based screening process. Other pollutants with
relatively high failure rates include acetaldehyde, acrylonitrile, carbon tetrachloride,
1,2-dichloroethane, 1,2-dibromoethane, formaldehyde, and 1,1,2,2-tetrachloroethane. While each
of these pollutants failed more than 98 percent of screens, four of them (acrylonitrile,
1,2-dichloroethane, 1,2-dibromoethane, and 1,1,2,2-tetrachloroethane) were detected in fewer
than 25 percent of samples collected.
4-15
-------
Table 4-7. Results of the Program-Level Preliminary Risk-Based Screening
Pollutant
Formaldehyde
Acet aldehyde
Benzene
Carbon Tetrachloride
Naphthalene
1,3-Butadiene
Arsenic
Manganese
Ethylbenzene
p-Dichlorobenzene
1 ,2-Dichloroethane
Acrylonitrile
Acenaphthene
Fluorene
Hexachloro- 1 , 3 -butadiene
Nickel
1 , 1 ,2,2-Tetrachloroethane
Propionaldehyde
Fluoranthene
Hexavalent Chromium
Cadmium
Trichloroethylene
Dichloromethane
1,2-Dibromoethane
Benzo(a)pyrene
Lead
Chloroform
Xylenes
Chloromethylbenzene
Acenaphthylene
Bromomethane
1,1,2-Trichloroethane
Carbon Bisulfide
Cobalt
Chloroprene
cis- 1 , 3 -Dichloropropene
trans- 1 ,3 -Dichloropropene
Tetrachloroethylene
Screening
Value
(Hg/m3)
0.077
0.45
0.13
0.17
0.029
0.03
0.00023
0.005
0.4
0.091
0.038
0.015
0.011
0.011
0.045
0.0021
0.017
0.8
0.011
0.000083
0.00056
0.2
7.7
0.0017
0.00057
0.015
9.8
10
0.02
0.011
0.5
0.0625
70
0.01
0.0021
0.25
0.25
3.8
Total
#of
Failed
Screens
1,592
1,570
1,488
1,261
1,074
995
694
518
401
351
320
300
132
117
105
97
55
49
43
40
36
35
34
31
19
17
14
12
9
4
4
4
2
2
1
1
1
1
11,429
#of
Measured
Detections
1,594
1,594
1,488
1,279
1,382
1,045
828
834
1,487
736
320
300
1,366
1,376
113
834
55
1,588
1,382
1,068
834
251
1,264
31
844
834
756
1,484
9
634
737
8
1,219
823
1
11
6
958
31,373
%of
Failed
Screens
99.87
98.49
100.00
98.59
77.71
95.22
83.82
62.11
26.97
47.69
100.00
100.00
9.66
8.50
92.92
11.63
100.00
3.09
3.11
3.75
4.32
13.94
2.69
100.00
2.25
2.04
1.85
0.81
100.00
0.63
0.54
50.00
0.16
0.24
100.00
9.09
16.67
0.10
36.43
%of
Total
Failures
13.93
13.74
13.02
11.03
9.40
8.71
6.07
4.53
3.51
3.07
2.80
2.62
1.15
1.02
0.92
0.85
0.48
0.43
0.38
0.35
0.31
0.31
0.30
0.27
0.17
0.15
0.12
0.10
0.08
0.03
0.03
0.03
0.02
0.02
0.01
0.01
0.01
0.01
Cumulative
%
Contribution
13.93
27.67
40.69
51.72
61.12
69.82
75.89
80.43
83.94
87.01
89.81
92.43
93.59
94.61
95.53
96.38
96.86
97.29
97.66
98.01
98.33
98.64
98.93
99.20
99.37
99.52
99.64
99.75
99.83
99.86
99.90
99.93
99.95
99.97
99.97
99.98
99.99
100.00
BOLD = EPA MQO NATTS Core Analyte
4-16
-------
The 18 NATTS MQO Core Analytes (excluding acrolein) are bolded in Table 4-7.
Several NATTS MQO Core Analytes failed screens, but did not contribute to the top 95 percent
of failed screens (such as hexavalent chromium). However, as described in Section 3.2, all
NATTS MQO Core Analytes are inherently designated as program-wide pollutants of interest.
Two pollutants, beryllium and vinyl chloride, were added as pollutants of interest because they
are NATTS MQO Core Analytes, even though they did not fail any screens. These two
pollutants are not shown in Table 4-7. Note that seven of the 15 pollutants contributing to the top
95 percent of failed screens (ethylbenzene,/>-dichlorobenzene, 1,2-dichloroethane, acrylonitrile,
acenaphthene, fluorene, and hexachloro-1,3-butadiene) are not NATTS MQO Core Analytes.
The program-level pollutants of interest, as indicated by the shading and/or bolding in
Table 4-7, were identified as follows:
Acenaphthene 1,2-Dichloroethane
Acetaldehyde
Acrylonitrile
Arsenic
Benzene
Benzo(a)pyrene
Beryllium
1,3-Butadiene
Cadmium
Carbon Tetrachloride
Chloroform
/>-Dichlorobenzene
Ethylbenzene
Fluorene
Formaldehyde
Hexachloro-1,3-butadiene
Hexavalent Chromium
Lead
Manganese
Naphthalene
Nickel
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
4-17
-------
The list of pollutants of interest identified via the preliminary risk-based screening
approach for 2011 is similar to the list of pollutants of interest for 2010. There is, however, one
exception. Hexachloro-1,3-butadiene was not identified as a pollutant of interest for 2010,
although it did fail screens. This pollutant was detected in 10 times as many samples in 2011
compared to 2010 and failed roughly 10 times more screens in 2011 than in 2010.
Of the 81 pollutants sampled for under the NMP that have corresponding screening
values, concentrations of 38 pollutants failed at least one screen (or roughly 48 percent of
pollutants). Of these, a total of 11,429 out of 31,373 concentrations (or 36.4 percent) failed
screens. If the measured detections for vinyl chloride and beryllium (the two NATTS MQO Core
Analytes that did not fail any screens) are included in the total number of concentrations
(32,259), the percentage of failed screens is 35.4 percent. If all of the pollutants with screening
values are considered (including those that did not fail any screens), the percentage of
concentrations failing screens is less (11,429 of 53,222, or 21.5 percent).
Table 4-8 presents the total number of failed screens per site, in descending order, as a
means of comparing the results of the preliminary risk-based screening process across the sites.
As shown, S4MO has the largest number of failed screens (602), followed by PXSS (589) and
NBIL (556). In addition to the number of failed screens, Table 4-8 also provides the total number
of screens conducted (one screen per valid preprocessed daily measurement for each site for all
pollutants with screening values). The failure rate, as a percentage, was determined from the
number of failed screens and the total number of screens conducted (based on applicable
measured detections) and is also provided in Table 4-8.
4-18
-------
Table 4-8. Site-Specific Risk-Based Screening Comparison
Site
S4MO
PXSS
NBIL
TOOK
TMOK
BTUT
GPCO
SEWA
DEMI
OCOK
PROK
MWOK
ELNJ
SPIL
NBNJ
CHNJ
SSSD
GLKY
UCSD
UNVT
SKFL
SYFL
SPAZ
SJJCA
RICO
PACO
AZFL
BURVT
BOMA
ORFL
INDEM
MONY
RRMI
BMCO
WPIN
ROCH
RUVT
CAMS 35
BRCO
PRRI
CELA
#of
Failed
Screens
602
589
556
521
511
510
498
482
468
457
422
417
406
405
364
345
319
303
300
179
176
156
154
143
142
125
123
123
122
120
115
115
110
102
102
97
96
75
70
66
64
Total # of
Measured
Detections1
2,724
2,584
2,662
1,701
1,769
2,473
2,076
2,531
2,112
1,776
1,640
1,654
1,319
1,236
1,266
1,244
1,251
2,142
1,143
1,884
964
814
549
1,243
414
395
186
533
1,471
180
171
893
169
367
153
735
472
629
331
798
691
%of
Failed
Screens
22.10
22.79
20.89
30.63
28.89
20.62
23.99
19.04
22.16
25.73
25.73
25.21
30.78
32.77
28.75
27.73
25.50
14.15
26.25
9.50
18.26
19.16
28.05
11.50
34.30
31.65
66.13
23.08
8.29
66.67
67.25
12.88
65.09
27.79
66.67
13.20
20.34
11.92
21.15
8.27
9.26
#of
Pollutant
Groups
Analyzed
5
5
6
3
3
6
4
5
4
3
3
3
2
2
2
2
3
5
3
4
3
3
1
2
2
2
1
1
3
1
1
2
1
2
1
2
1
2
2
2
1
1 Total number of measured detections for all pollutants with
screening values, not just those failing screens.
BOLD ITALICS = EPA-designaled NATTS Site
4-19
-------
Table 4-8. Site-Specific Risk-Based Screening Comparison (Continued)
Site
PANJ
WADC
RIVA
SWMI
SDGA
RUCA
PAFL
CHSC
CAMS 85
HOW
#of
Failed
Screens
63
61
57
57
56
54
28
3
0
0
Total # of
Measured
Detections1
237
731
681
84
668
625
308
452
50
41
%of
Failed
Screens
26.58
8.34
8.37
67.86
8.38
8.64
9.09
0.66
0.00
0.00
#of
Pollutant
Groups
Analyzed
1
2
2
1
2
1
1
2
1
1
1 Total number of measured detections for all pollutants with
screening values, not just those failing screens.
BOLD ITALICS = EPA-designaled NATTS Site
The total number of screens and the number of pollutant groups measured by each site
must also be considered when interpreting the results in Table 4-8. For example, sites sampling
three, four, or five pollutant groups tended to have a higher number of failed screens. Although
WPIN, ORFL, INDEM, and SWMI have the highest failure rates (67-68 percent each), these
sites sampled only one pollutant group (carbonyl compounds). Three pollutants measured with
Method TO-11A (carbonyl compounds) have screening values (acetaldehyde, formaldehyde, and
propionaldehyde) and two of these pollutants typically fail all or most of the screens conducted,
as shown in Table 4-7. Thus, sites sampling only carbonyl compounds have relatively high
failure rates. Conversely, sites that sampled several pollutant groups tended to have lower failure
rates due to the larger number of HAPs screened, as is the case with S4MO, PXSS, NBIL,
BTUT, and SEWA. These sites each sampled five or six pollutant groups and have a failure rate
around 20 percent. For this reason, the number of pollutant groups for which sampling was
conducted is also presented in Table 4-8. Note that measurements for two sites, HOWI and
CAMS 85, did not fail any screens (both of these sites sampled only hexavalent chromium).
The following sections from this point forward focus only on those pollutants designated
as program-level pollutants of interest.
4-20
-------
4.2.1 Concentrations of the Pollutants of Interest
Concentrations of the program-level pollutants of interest vary significantly, among the
pollutants and among the sites. Tables 4-9 through 4-12 present the top 10 annual average
concentrations and 95 percent confidence intervals by site for each of the program-level
pollutants of interest (for VOCs, carbonyl compounds, PAHs, and metals respectively). As
described in Section 3.1, an annual average is the average concentration of all measured
detections and zeros substituted for non-detects for a given year. Further, an annual average is
only considered valid where there are at least three quarterly averages and where the site-specific
method completeness is at least 85 percent. The annual average concentrations for PAHs in
Table 4-11 and metals in Table 4-12 are reported in ng/m3 for ease of viewing, while annual
average concentrations in Tables 4-9 and 4-10, for VOCs and carbonyl compounds, respectively,
are reported in ug/m3. Note that not all sites sampled each pollutant; thus, the list of possible
sites presented in Tables 4-9 through 4-12 is limited to those sites sampling each pollutant. For
example, only five sites sampled TSP metals; thus, all five sites appear in Table 4-12 for each
metal (TSP) pollutant of interest shown.
4-21
-------
Table 4-9. Annual Average Concentration Comparison of the VOC Pollutants of Interest
to
to
Rank
1
2
3
4
5
6
7
8
9
10
Acrylonitrile
(Hg/m3)
SPIL
0.77 ฑ0.11
UCSD
0.17 ฑ0.04
GLKY
0.16 ฑ0.07
NBIL
0.13 ฑ0.03
CHNJ
0.10 ฑ0.05
NBNJ
0.09 ฑ0.05
TMOK
0.08 ฑ 0.07
OCOK
0.07 ฑ0.05
GPCO
0.06 ฑ0.03
ELNJ
0.04 ฑ0.03
Benzene
(jig/m )
TOOK
3.59 ฑ0.98
SPAZ
1.65 ฑ0.45
PACO
1.45 ฑ0.21
TMOK
1.35ฑ0.18
PXSS
1.34 ฑ0.22
GPCO
1.34 ฑ0.35
RICO
1.27 ฑ0.18
BTUT
1.14ฑ0.15
ELNJ
1.03 ฑ0.13
RUVT
0.89 ฑ0.16
1,3-Butadiene
(Hg/m3)
SPAZ
0.29 ฑ0.10
PXSS
0.23 ฑ 0.06
OCOK
0.20 ฑ0.31
RICO
0.18 ฑ0.04
SPIL
0.16 ฑ0.03
ELNJ
0.14 ฑ0.02
GPCO
0.13 ฑ0.02
NBIL
0.12 ฑ0.10
TMOK
0.10 ฑ0.02
BTUT
0.10 ฑ0.02
Carbon
Tetrachloride
(Hg/m3)
DEMI
0.65 ฑ0.02
SEWA
0.65 ฑ0.03
NBIL
0.64 ฑ0.03
PXSS
0.63 ฑ0.03
SPAZ
0.63 ฑ0.07
TOOK
0.63 ฑ0.05
GLKY
0.63 ฑ0.03
CHNJ
0.62 ฑ0.03
PROK
0.62 ฑ0.03
S4MO
0.61 ฑ0.04
Chloroform
(Hg/m3)
NBIL
6.06 ฑ2.17
DEMI
0.82 ฑ0.14
PXSS
0.37 ฑ0.07
S4MO
0.35 ฑ0.40
SPAZ
0.18 ฑ0.04
ELNJ
0.14 ฑ0.03
NBNJ
0.13 ฑ0.02
SEWA
0.12 ฑ0.01
CHNJ
0.10 ฑ0.03
SPIL
0.09 ฑ0.02
/7-Dichlorobenzene
(Hg/m3)
SPAZ
0.26 ฑ 0.07
S4MO
0.21ฑ0.11
PROK
0.20 ฑ 0.07
PXSS
0.20 ฑ 0.04
TOOK
0.15 ฑ0.03
ELNJ
0.10 ฑ0.02
MWOK
0.09 ฑ0.01
TMOK
0.08 ฑ0.02
SPIL
0.07 ฑ0.03
BURVT
0.07 ฑ0.01
BOLD ITALICS = EPA-designaled NATTS Site
-------
Table 4-9. Annual Average Concentration Comparison of the VOC Pollutants of Interest (Continued)
Rank
1
2
3
4
5
6
7
8
9
10
1,2-Dichloro ethane
(Hg/m3)
CHNJ
0.034 ฑ0.019
S4MO
0.032 ฑ0.013
OCOK
0.031 ฑ0.024
NBNJ
0.030 ฑ0.012
ELNJ
0.028 ฑ0.014
PROK
0.028 ฑ0.012
GLKY
0.028 ฑ0.01
BTUT
0.028 ฑ0.013
GPCO
0.027 ฑ0.012
UCSD
0.026 ฑ0.011
Ethylbenzene
(Hg/m3)
SPAZ
1.06 ฑ0.28
PXSS
0.82 ฑ0.13
TOOK
0.68 ฑ0.13
GPCO
0.62 ฑ0.11
DEMI
0.61 ฑ0.13
TMOK
0.55 ฑ0.09
ELNJ
0.51 ฑ0.16
NBNJ
0.49 ฑ0.39
BTUT
0.47 ฑ0.13
S4MO
0.38 ฑ0.04
Hexachloro-1,3-
Butadiene
(Hg/m3)
S4MO
0.023 ฑ0.014
BURVT
0.019 ฑ0.015
MWOK
0.017 ฑ0.023
SPIL
0.016 ฑ0.025
NBNJ
0.015 ฑ0.01
GPCO
0.014 ฑ0.01
GLKY
0.014 ฑ0.009
UCSD
0.013 ฑ0.011
CHNJ
0.011 ฑ0.009
BTUT
0.010 ฑ0.008
Tetrachloroethylene
(Hg/m3)
PXSS
0.55 ฑ0.28
SPAZ
0.41 ฑ0.16
NBIL
0.35 ฑ0.13
SPIL
0.31 ฑ0.08
GPCO
0.26 ฑ0.05
ELNJ
0.20 ฑ0.05
DEMI
0.18 ฑ0.03
S4MO
0.18 ฑ0.04
MWOK
0.15 ฑ0.06
NBNJ
0.13 ฑ0.02
Trichloroethylene
(Hg/m3)
SPIL
0.64 ฑ0.41
ELNJ
0.09 ฑ0.09
SPAZ
0.05 ฑ0.03
CHNJ
0.05 ฑ0.09
NBIL
0.04 ฑ 0.02
GPCO
0.04 ฑ 0.02
S4MO
0.03 ฑ0.01
NBNJ
0.02 ฑ0.01
PXSS
0.02 ฑ0.01
UCSD
0.02 ฑ 0.02
Vinyl Chloride
(Hg/m3)
NBIL
0.003 ฑ 0.002
NBNJ
0.003 ฑ 0.002
SPIL
0 003 ฑ 0 003
S4MO
0.003 ฑ 0.002
DEMI
0.003 ฑ 0.002
CHNJ
0.002 ฑ 0.002
GPCO
0.002 ฑ 0.002
OCOK
0.001 ฑ0.002
PXSS
0.001 ฑ0.001
UCSD
0.001 ฑ0.001
J^.
K>
BOLD ITALICS = EPA-designated NATTS Site
-------
Table 4-10. Annual Average Concentration Comparison of the Carbonyl Compound Pollutants of Interest
J^.
K>
Rank
1
2
3
4
5
6
7
8
9
10
Acet aldehyde
(Ug/m3)
ELNJ
3.24 ฑ0.39
SPIL
2.94 ฑ0.61
S4MO
2.75 ฑ0.43
TOOK
2.75 ฑ0.41
NBNJ
2.49 ฑ0.27
GPCO
2.43 ฑ0.29
OCOK
2.41 ฑ0.33
TMOK
2.40 ฑ0.34
UCSD
2.33 ฑ0.40
BTUT
2.19 ฑ0.35
Formaldehyde
(Ug/m3)
BTUT
4.49 ฑ1.15
S4MO
4.25 ฑ 0.92
OCOK
4 06 ฑ 0 80
MWOK
4.05 ฑ0.53
TMOK
3.93 ฑ0.62
PROK
3.84 ฑ0.67
TOOK
3.74 ฑ0.57
ELNJ
3.45 ฑ0.44
SPIL
3.29 ฑ0.46
RRMI
3.23 ฑ0.47
BOLD ITALICS = EPA-designated NATTS Site
-------
Table 4-11. Annual Average Concentration Comparison of the PAH Pollutants of Interest
to
Rank
1
2
3
4
5
6
7
8
9
10
Acenaphthene
(ng/m3)
DEMI
13.42 ฑ5. 17
NBIL
13.14ฑ4.14
ROCH
12.29 ฑ3.55
GPCO
10.54 ฑ2.17
MONY
8.99 ฑ1.80
CAMS 35
6.58 ฑ2.30
S4MO
5.41 ฑ1.45
CELA
4.92 ฑ0.76
PRRI
3 65 ฑ083
RIVA
3. 13 ฑ0.64
Benzo(a)pyrene
(ng/m3)
GPCO
0.20 ฑ0.08
MONY
0.20 ฑ 0.04
DEMI
0.19 ฑ0.07
PRRI
0.16 ฑ0.03
NBIL
0.15 ฑ0.03
S4MO
0.13 ฑ0.03
BOMA
0.11 ฑ0.02
PXSS
0.10 ฑ0.04
ROCH
0.09 ฑ0.03
SEWA
0.08 ฑ0.05
Fluorene
(ng/m3)
NBIL
13.46 ฑ4.25
DEMI
11.19ฑ3.84
ROCH
9.92 ฑ2.81
MONY
9.47 ฑ1.55
CAMS 35
7.84 ฑ2.85
GPCO
7.68 ฑ0.98
S4MO
6.08 ฑ 1.40
CELA
5.62 ฑ0.70
PRRI
4.97 ฑ0.96
RUCA
4.09 ฑ0.56
Naphthalene
(ng/m3)
GPCO
155. 52 ฑ29.71
DEMI
143. 35 ฑ23.07
MONY
135.66 ฑ15.50
CELA
131. 96 ฑ21.23
WADC
102.71 ฑ20.46
NBIL
99.39 ฑ29.75
CAMS 35
94. 14 ฑ18.02
PRRI
91.41 ฑ14.27
RUCA
91. 18 ฑ17.14
SDGA
90.82 ฑ15.61
BOLD ITALICS = EPA-designated NATTS Site
-------
Table 4-12. Annual Average Concentration Comparison of the Metals Pollutants of Interest
to
Rank
1
2
o
J
4
5
6
7
8
9
10
Arsenic
(PM10)
(ng/m3)
S4MO
0.87 ฑ0.14
PXSS
0.77 ฑ0.16
NBIL
0.73 ฑ0.15
Sฃ^
0.66 ฑ0.12
PAFL
0.62 ฑ0.17
BTUT
0.59 ฑ0.19
BOM4
0.43 ฑ 0.07
SJJCA
0.39 ฑ0.07
UNVT
0.25 ฑ 0.06
Arsenic
(TSP)
(ng/m3)
TOOK
0.76 ฑ0.08
TMOK
0.63 ฑ 0.08
PROK
0.54 ฑ0.07
OCOK
0.47 ฑ 0.07
MWOK
0.40 ฑ 0.04
Beryllium
(PM10)
(ng/m3)
PXSS
0.047 ฑ0.016
BTUT
0.013 ฑ0.004
BOMA
0.010 ฑ0.007
S4MO
0.008 ฑ 0.002
NBIL
0 007 ฑ 0 004
SJJCA
0.007 ฑ0.001
SEWA
0.006 ฑ 0.005
UNVT
0.006 ฑ 0.002
PAFL
0.004 ฑ0.001
Beryllium
(TSP)
(ng/m3)
PROK
0.029 ฑ 0.006
TOOK
0.026 ฑ 0.004
MWOK
0.019 ฑ0.003
OCOK
0.018 ฑ0.003
TMOK
0.018 ฑ0.003
Cadmium
(PM10)
(ng/m3)
S4MO
0.56 ฑ0.12
NBIL
0 1 4 ฑ 0 03
BTUT
0.14 ฑ0.05
PXSS
0.14 ฑ0.03
BOMA
0.13 ฑ0.01
SEWA
0.10 ฑ0.03
SJJCA
0.07 ฑ 0.02
UNVT
0.07 ฑ0.01
PAFL
0.06 ฑ0.01
Cadmium
(TSP)
(ng/m3)
TOOK
0.31 ฑ0.08
TMOK
0.22 ฑ0.03
PROK
0.16 ฑ0.02
OCOK
0.13 ฑ0.03
MWOK
0.12 ฑ0.02
Hexavalent
Chromium
(ng/m3)
PXSS
0.065 ฑ0.012
CAMS 35
0.050 ฑ 0.007
DEMI
0.047 ฑ 0.009
MONY
0.041 ฑ0.005
SEWA
0.033 ฑ 0.007
S4MO
0.033 ฑ 0.006
BOMA
0.026 ฑ 0.006
SKFL
0 023 ฑ 0 005
PRRI
0.022 ฑ 0.006
CAMS 85
0.022 ฑ 0.003
BOLD ITALICS = EPA-designated NATTS Site
-------
Table 4-12. Annual Average Concentration Comparison of the Metals Pollutants of Interest (Continued)
to
Rank
1
2
o
J
4
5
6
7
8
9
10
Lead
(PM10)
(ng/m3)
S4MO
10.42 ฑ 1.72
NBIL
4.16 ฑ1.07
PXSS
4.06 ฑ 0.64
BTUT
3.51 ฑ0.98
BOMA
3.07 ฑ0.44
SJJCA
3.02 ฑ0.56
SEWA
2.89 ฑ0.44
PAFL
2.13 ฑ0.47
UNVT
1.46 ฑ0.29
Lead
(TSP1
(ng/m5)
TOOK
5.87 ฑ0.87
TMOK
4.91 ฑ0.64
PROK
2.69 ฑ0.3
OCOK
2.61 ฑ0.26
MWOK
2.48 ฑ0.22
Manganese
(PM10)
(ng/m3)
PXSS
22.82 ฑ6.79
S4MO
18.42 ฑ13. 18
NBIL
8.30 ฑ2.29
SEWA
8.17 ฑ2.57
BTUT
7.58 ฑ1.27
SJJCA
6.62 ฑ1.14
BOMA
3.48 ฑ0.44
PAFL
2.23 ฑ0.35
UNVT
1.84 ฑ0.32
Manganese
(TSP1
(ng/nr5)
TOOK
30.09 ฑ4.58
TMOK
20.52 ฑ3.06
OCOK
14.04 ฑ2.01
MWOK 13.26
ฑ1.94
PROK
11. 31 ฑ1.88
Nickel
(PM10)
(ng/m3)
SEWA
1.90 ฑ0.46
PXSS
1.74 ฑ0.33
BTUT
1.73 ฑ0.35
BOMA
1.38 ฑ0.17
NBIL
1.27 ฑ0.21
SJJCA
1.27 ฑ0.17
S4MO
1.20 ฑ0.26
PAFL
0.72 ฑ0.10
UNVT
0.53 ฑ0.10
Nickel
(TSP1
(ng/m5)
TOOK
1.75 ฑ0.19
TMOK
1.42 ฑ0.19
MWOK
1.20 ฑ0.21
OCOK
0.84 ฑ0.08
PROK
0.79 ฑ0.09
BOLD ITALICS = EPA-designated NATTS Site
-------
Observations from Tables 4-9 through 4-12 include the following:
The highest annual average concentration among the program-wide pollutants of
interest was calculated for chloroform for NBIL (6.06 ฑ2.17 |ig/m3). As shown in
Table 4-9, this annual average concentration is more than seven times the next
highest concentration of chloroform (DEMI, 0.82 ฑ 0.14 |ig/m3). The relatively large
confidence interval associated with this annual average indicates a wide range of
concentrations are factored into this average. Twenty-five of the 26 highest
chloroform concentrations measured program-wide, ranging from 2.61 |ig/m3to
32.9 |ig/m3, were measured at NBIL. NBIL also had the highest annual average
chloroform concentration among sites sampling this pollutant in 2010.
Behind NBIL's chloroform concentration, the next four highest annual average
concentrations were calculated for formaldehyde, ranging from 4.05 ฑ 2.17 |ig/m3
(MWOK) to 4.49 ฑ2.17 |ig/m3 (BTUT). All other annual average concentrations
were less than 4.0 |ig/m3. Formaldehyde and acetaldehyde account for 30 of the 32
annual average concentrations greater than 2.0 |ig/m3 in Tables 4-9 through 4-12 (the
two exceptions being for NBIL's chloroform and TOOK's benzene).
Among the VOCs, the annual average concentrations of benzene are the only annual
averages consistently greater than 1 |ig/m3. TOOK's annual average benzene
concentration (3.59 ฑ 0.98 |ig/m3) is significantly higher than the next highest annual
average benzene concentration (1.65 ฑ 0.45 |ig/m3 for SPAZ), which is similar to the
2010 NMP report. Across the program, four of the five benzene measurements
greater than 10 |ig/m3 (and 11 of the 15 benzene concentrations greater than 5 |ig/m3)
were measured at TOOK. Three of the five Colorado sites have one of the top 10
annual average benzene concentrations and both Tulsa, Oklahoma sites appear in
Table 4-9 for benzene.
The difference between the highest and tenth highest annual average concentration of
carbon tetrachloride is only 0.04 |ig/m3. The difference between the highest and
lowest annual average concentration of this pollutant among all NMP sites is
0.12 |ig/m3, indicating the relative uniformity in concentrations of this pollutant in
ambient air.
The annual average concentration of acrylonitrile for SPIL (0.77 ฑ0.11 |ig/m3) is
more than four times higher than the next highest annual average concentration of
this pollutant (0.17 ฑ 0.04 |ig/m3 for UCSD). Thirty-one of the 38 highest
concentrations of acrylonitrile (those greater than 0.75 |ig/m3) were measured at SPIL
and of the 24 measurements greater than 1.0 |ig/m3 program-wide, 19 were measured
at SPIL. However, the highest concentration of acrylonitrile (1.69 |ig/m3) was not
measured at SPIL; it was measured at TMOK.
The only other VOC for which an annual average concentration was greater than
1.0 |ig/m3 was calculated for ethylbenzene (SPAZ, 1.06 ฑ 0.28 |ig/m3). SPAZ had the
second highest number of ethylbenzene concentrations greater than 1 |ig/m3 (12),
behind only PXSS (20), which had the second highest annual average concentration
of ethylbenzene (0.82 ฑ 0.13 |ig/m3).
4-28
-------
The annual average concentration of trichloroethylene for SPIL (0.64 ฑ 0.41 |ig/m3)
is seven times higher than the next highest annual average
(ELNJ, 0.09 ฑ 0.09 |ig/m3). Of the 13 concentrations of trichloroethylene measured
across the program that are greater than 0.75 |ig/m3, 10 were measured at SPIL (and
two were measured at ELNJ). Similar trends in SPIL's trichloroethylene
concentrations were seen in the 2008-2009 and 2010 NMP reports. The confidence
intervals shown for both sites indicate a relatively high-level of variability in the
measurements. Note that trichloroethylene was detected in 75 percent of samples at
SPIL and 40 percent of samples at ELNJ.
Although BTUT has the highest annual average concentration of formaldehyde
(4.49 ฑ1.15 |ig/m3), the maximum concentration was not measured at this site.
However, nine of the 26 concentrations greater than 10 |ig/m3 were measured at
BTUT. While just greater than 0.50 |ig/m3 separates the annual averages for the top
five sites, the confidence interval for BTUT's annual average suggests a slightly
higher level of variability in the measurements than the other sites. The site with the
maximum formaldehyde measurement (2.71 ฑ1.10 |ig/m3) is NBNJ, who's annual
average formaldehyde concentration ranked 13th.
Although ELNJ has the highest annual average concentration of acetaldehyde
(3.24 ฑ 0.39 |ig/m3), the maximum concentration was measured at SPIL (14.5 |ig/m3),
which has the second highest annual average concentration (2.94 ฑ 0.61 |ig/m3)
among sites sampling carbonyl compounds. These two sites account for 18 of the 51
acetaldehyde measurements greater than 5 |ig/m3 (10 for ELNJ and eight for SPIL).
Although GPCO has the highest annual average concentration of naphthalene
(155.52 ฑ 29.71 ng/m3), the highest measurement of this pollutant was not measured
at this site. NBIL has the maximum measurement among all sites sampling
naphthalene (799 ng/m3), although its annual average concentration ranked sixth
(99.39 ฑ 29.75 ng/m3). GPCO has the highest number of naphthalene measurements
greater than 300 ng/m3 (five) among sites sampling this pollutant.
S4MO has the highest annual average concentration of three of the six PMio metals:
arsenic, cadmium, and lead. In addition, S4MO's annual average manganese
concentration ranks second highest. Several of S4MO's annual averages, such as
lead, are significantly higher than the other annual averages listed. The two maximum
concentrations of lead across the program were measured at S4MO (30.9 ng/m3 and
27.5 ng/m3). Additionally, 22 of the 32 highest lead concentrations (those greater than
10 ng/m3) were measured at S4MO. The maximum manganese concentration among
all sites sampling PMio metals was measured at S4MO (395 ng/m3) and is more than
twice the next highest manganese concentration (130 ng/m3, measured at PXSS). The
maximum concentration of cadmium was also measured at S4MO, while the second
highest concentration of arsenic was measured at S4MO (behind only BTUT).
TOOK has the highest annual average concentration of five of the six TSP metals:
arsenic, cadmium, lead, manganese, nickel. TOOK's annual average beryllium
concentration ranked second, behind PROK. Note that only Oklahoma sites sampled
TSP metals.
4-29
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S4MO was on the top 10 list for 21 of the 25 program-level pollutants of interest;
PXSS and NBIL were both on the top 10 list for 17 of the 25 program-level pollutants
of interest. GPCO appears in Tables 4-9 through 4-12 a total of 14 times. Conversely,
12 sites do not appear in Table 4-9 through 4-12 at all. Note, however, that some sites
did not meet the criteria for annual averages to be calculated.
4.2.2 Risk-Based Screening Assessment Using MRLs
Table 4-13 presents the pollutants analyzed under the NMP that have associated ATSDR
MRLs. Note that some pollutants do not have MRLs for one or more of the designated time
frames (acute, intermediate, or chronic). None of the preprocessed daily measurements are
greater than associated acute MRL; none of the quarterly average concentrations, where they
could be calculated, are greater than the associated intermediate MRL; and none of the annual
average concentrations, where they could be calculated, are greater than the associated chronic
MRL. Thus, Table 4-13 also presents the maximum preprocessed daily measurement, quarterly
average, and annual average concentration associated with each pollutant. This allows the reader
to see how close (or how far) from the MRL(s) some concentrations were. For example, the
acute MRL for benzene is 30 |ig/m3 and the maximum concentration measured was nearly
24 |ig/m3. Conversely, the acute MRL for acetone is 60,000 |ig/m3 while the maximum
concentration measured was 15.4 |ig/m3.
The pollutant with the concentration closest to the acute MRL is benzene (the acute MRL
is 30 |ig/m3 and the maximum benzene measurement is 23.8 |ig/m3). The pollutant with the
quarterly average concentration closest to the intermediate MRL is also benzene (the
intermediate MRL is 20 |ig/m3 and the maximum quarterly average is 4.39 |ig/m3). The pollutant
with the annual average concentration closest to the chronic MRL is manganese (the chronic
MRL is 0.04 |ig/m3 and the maximum annual average is 0.03 |ig/m3).
Because none of the preprocessed daily measurements are greater than associated acute
MRLs, the emission tracer analysis described in Section 3.5.5.1 was not performed.
4-30
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Table 4-13. Comparison of Maximum Concentrations vs. ATSDR MRLs
Pollutant
Acetone
Acrylonitrile
Benzene
Bromomethane
1,3 -Butadiene
Cadmium
Carbon Bisulfide
Carbon Tetrachloride
Chloroethane
Chloroform
Chloromethane
Chromium
Cobalt
ฃ>-Dichlorobenzene
1,2-Dichloroethane
1, 1-Dichloroethene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 , 3 -Dichloropropene
trans- 1 ,3 -Dichloropropene
Ethylbenzene
Formaldehyde
w-Hexane
Hexavalent Chromium
Manganese
Mercury
Methyl tert-Butyl Ether
ATSDR Acute
MRL1
(Hg/m3)
60,000
200
30
200
200
0.03
40,000
500
1,000
10,000
800
2,000
200
20,000
50
7,000
Maximum
Prep recessed Daily
Measurement
(Hg/m3)
15.40
1.69
23.80
1.70
9.51
0.01
21.60
32.90
5.24
2.83
0.20
1,214.00
0.06
11.50
27.70
0.99
ATSDR
Intermediate
MRL1
(Hg/m3)
30,000
20
200
200
200
400
0.3
1,000
80
800
1,000
30
40
40
9,000
40
0.3
3,000
Maximum
Quarterly Average
Concentration
(Hg/m3)
9.67
4.39
0.20
0.72
12.41
1.55
<0.01
0.54
<0.01
0.03
156.90
<0.01
0.03
0.02
1.65
8.37
0.01
0.08
ATSDR Chronic
MRL1
(Hg/m3)
30,000
10
20
0.01
900
200
100
100
0.1
60
2,000
1,000
30
30
300
10
2,000
0.04
0.2
3,000
Maximum Annual
Average
Concentration
(Hg/m3)
4.92
3.59
0.07
0.01
29.46
0.65
6.06
1.42
0.01
0.26
0.03
53.90
0.01
0.01
1.06
4.49
4.41
0.03
O.01
0.02
Reflects the use of one significant digit for MRLs
-------
Table 4-13. Comparison of Maximum Concentrations vs. ATSDR MRLs (Continued)
Pollutant
Naphthalene
Nickel
Styrene
Tetrachloroethylene
Toluene
1,1,1 -Trichloroethane
Trichloroethylene
Vinyl Chloride
Xylenes
ATSDR Acute
MRL1
(Hg/m3)
20,000
1,000
4,000
10,000
10,000
1,000
9,000
Maximum
Prep recessed Daily
Measurement
(Hg/m3)
13.10
8.63
93.90
0.44
8.40
0.08
34.76
ATSDR
Intermediate
MRL1
(Hg/m3)
0.2
4,000
500
80
3,000
Maximum
Quarterly Average
Concentration
(Hg/m3)
0.01
0.10
1.28
0.01
6.45
ATSDR Chronic
MRL1
(Hg/m3)
4
0.09
900
300
300
200
Maximum Annual
Average
Concentration
(Hg/m3)
0.16
0.01
1.45
0.55
6.41
4.06
Reflects the use of one significant digit for MRLs
-^
to
-------
4.3 The Impact of Mobile Sources
Ambient air is significantly impacted by mobile sources, as discussed in Section 3.4.1.
Table 4-14 contains several parameters that are used to assess mobile source impacts on air
quality near the monitoring sites, including emissions data from the NEI, concentration data, and
site-characterizing data, such as vehicle ownership.
4.3.1 Mobile Source Emissions
Emissions from mobile sources account for nearly half of air pollution in the United
States. Mobile source emissions can be broken into two categories: on-road and non-road. On-
road emissions come from mobile sources such as automobiles, buses, and construction vehicles
that use roadways; non-road emissions come from the remaining mobile sources such as
locomotives, lawn mowers, and boats (EPA, 20121). Table 4-14 contains county-level on-road
and non-road HAP emissions from the 2008 NEI.
Mobile source emissions tend to be highest in large urban areas and lowest in rural areas.
Estimated on-road county emissions were highest in Los Angeles County, CA (where CELA is
located), followed by Harris County, TX (where CAMS 35 is located), and Maricopa County,
AZ (where PXSS and SPAZ are located) while estimated on-road emissions were lowest in
Chesterfield County, SC and Union County, SD (where CHSC and UCSD are located,
respectively). Estimated non-road county emissions were also highest in Los Angeles County,
CA, followed by Cook County, IL (where NBIL and SPIL are located) and Maricopa County,
AZ. Estimated non-road county emissions were lowest in Union County, SD and Carter County,
KY (where GLKY is located).
4-33
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Table 4-14. Summary of Mobile Source Information by Monitoring Site
Site
AZFL
BMCO
BOMA
BRCO
BTUT
BURVT
CAMS 35
CAMS 85
CELA
CHNJ
CHSC
DEMI
ELNJ
GLKY
GPCO
HOW
INDEM
MONY
MWOK
NBIL
NBNJ
OCOK
ORFL
PACO
PAFL
County-level
Motor Vehicle
Registration1
(# of Vehicles)
877,075
72,957
481,199
72,957
239,582
169,767
3,164,173
70,585
7,360,573
389,359
40,792
1,334,752
424,894
32,398
178,425
100,176
419,431
246,748
832,160
2,072,399
640,893
832,160
1,056,627
72,957
1,056,627
Estimated
10-Mile Vehicle
Ownership1
(# of Vehicles)
555,080
7,703
1,100,560
33,018
206,495
130,202
528,398
2,410
2,647,604
187,012
4,852
775,162
1,724,607
17,159
145,607
24,846
348,652
1,007,684
427,423
353,553
637,915
429,679
907,230
7,703
795,455
Annual
Average Daily
Traffic1
(# of Vehicles)
40,500
2,527
31,400
150
113,955
14,000
31,043
1,250
230,000
12,917
550
92,800
250,000
428
11,000
5,000
34,240
91,465
40,900
34,600
114,322
40,900
32,500
16,000
46,000
County-level
Daily VMT1
21,395,381
1,901,434
10,695,874
1,901,434
6,866,779
4,027,945
56,650,489
2,578,700
214,458,140
14,256,044
1,276,517
42,804,737
12,485,902
1,084,000
2,031,327
2,626,054
16,226,000
9,698,000
27,190,328
86,863,779
20,415,685
27,190,328
33,325,315
1,901,434
33,325,315
County-Level
On-road
Emissions2
(tpy)
2,650.97
260.03
715.05
260.03
861.85
371.91
8,521.88
284.17
9,556.40
1,202.20
128.86
5,900.70
951.86
163.87
392.28
247.41
1,222.76
825.34
2,900.47
7,721.47
1,617.22
2,900.47
3,198.03
260.03
3,198.03
County-Level
Non-road
Emissions2
(tpy)
1,157.75
93.05
440.97
93.05
336.23
251.44
2,791.78
129.54
5,072.27
705.27
80.37
1,113.36
390.19
15.58
180.83
220.50
634.27
391.72
816.74
4,074.66
673.13
816.74
1,587.50
93.05
1,587.50
Hydrocarbon
Average3
(ppbv)
NA
NA
NA
NA
3.75
2.42
NA
NA
NA
1.81
NA
3.27
4.48
1.30
4.67
NA
NA
NA
1.90
5.71
2.66
2.42
NA
NA
NA
Reference: EPA, 2012d
3This parameter is only available for monitoring sites sampling VOCs.
BOLD ITALICS = EPA-designated NATTS Site
NA = Data not available
-------
Table 4-14. Summary of Mobile Source Information by Monitoring Site (Continued)
Site
PANJ
PROK
PRRI
PXSS
RICO
RIVA
ROCH
RRMI
RUCA
RUVT
S4MO
SDGA
SEWA
SJJCA
SKFL
SPAZ
SPIL
SSSD
SWMI
SYFL
TMOK
TOOK
UCSD
UNVT
WADC
WPIN
County-level
Motor Vehicle
Registration1
(# of Vehicles)
396,602
39,968
485,837
3,776,819
72,957
354,721
550,992
1,334,752
1,711,492
70,900
1,114,812
472,535
1,783,335
1,517,190
877,075
3,776,819
2,072,399
210,914
1,334,752
1,135,945
603,926
603,926
25,419
169,767
213,232
820,767
Estimated
10-Mile Vehicle
Ownership1
(# of Vehicles)
1,071,818
29,285
509,773
1,314,732
23,530
544,138
480,772
572,987
784,472
40,098
673,974
492,952
890,137
1,242,743
674,583
826,196
805,601
229,582
721,842
288,235
323,647
448,957
9,676
36,243
666,556
718,087
Annual
Average Daily
Traffic1
(# of Vehicles)
22,272
15,100
136,800
184,000
17,000
73,000
86,198
98,500
145,000
7,200
79,558
140,820
226,000
104,000
47,000
128,000
190,000
18,700
93,000
10,600
12,600
63,000
156
1,100
7,700
143,970
County-level
Daily VMT1
8,178,167
1,656,458
NA
89,448,000
1,901,434
8,246,774
17,772,000
42,804,737
55,717,760
1,766,027
19,896,584
20,187,000
23,282,703
41,250,490
21,395,381
89,448,000
86,863,779
3,751,886
42,804,737
34,351,899
20,348,926
20,348,926
808,049
4,027,945
9,775,000
32,005,000
County-Level
On-road
Emissions2
(tpy)
616.98
172.07
1,104.51
7,862.48
260.03
831.85
1,566.25
5,900.70
2,486.42
158.14
974.72
2,272.55
6,932.11
1,960.08
2,650.97
7,862.48
7,721.47
467.40
5,900.70
3,252.93
2,197.21
2,197.21
91.81
371.91
929.71
2,664.97
County-Level
Non-road
Emissions2
(tpy)
447.26
83.98
381.46
3,819.27
93.05
188.91
683.88
1,113.36
1,003.76
150.60
182.60
772.13
2,762.29
812.60
1,157.75
3,819.27
4,074.66
132.93
1,113.36
1,326.89
867.85
867.85
30.98
251.44
327.98
715.48
Hydrocarbon
Average3
(ppbv)
4.57
2.02
NA
5.16
NA
NA
NA
NA
NA
2.47
2.65
NA
2.37
NA
NA
6.74
2.86
1.75
NA
NA
3.89
9.15
0.98
0.94
NA
NA
Reference: EPA, 2012d
3This parameter is only available for monitoring sites sampling VOCs.
BOLD ITALICS = EPA-designated NATTS Site
NA = Data not available
-------
4.3.2 Hydrocarbon Concentrations
Hydrocarbons are organic compounds that contain only carbon and hydrogen.
Hydrocarbons are derived mostly from crude petroleum sources and are classified according to
their arrangement of atoms as alicyclic, aliphatic, and aromatic. Hydrocarbons are of prime
economic importance because they encompass the constituents of the major fossil fuels,
petroleum and natural gas, as well as plastics, waxes, and oils. Hydrocarbons in the atmosphere
originate from natural sources and from various anthropogenic sources, such as the combustion
of fuel and biomass, petroleum refining, petrochemical manufacturing, solvent use, and gas and
oil production and use. In urban air pollution, these components, along with oxides of nitrogen
(NOX) and sunlight, contribute to the formation of tropospheric ozone. Thus, the concentration of
hydrocarbons in ambient air may act as an indicator of mobile source activity levels. Several
hydrocarbons are sampled with Method TO-15, including benzene, ethylbenzene, and toluene.
Table 4-14 presents the average of the sum of hydrocarbon concentrations for each site
sampling VOCs. Note that only sites sampling VOCs have data in this column. Table 4-14 shows
that TOOK, SPAZ, and NBIL have the highest hydrocarbon averages among the sites monitoring
VOCs. Each of these sites is located in a highly populated urban area and in relatively close
proximity to heavily traveled roadways. For example, TOOK is located near Exit 3 A of 1-244 in
Tulsa, Oklahoma. The sites with the lowest hydrocarbon averages are GLKY, UCSD, and
UNVT. All three of these sites are located in rural areas. The average sum of hydrocarbon
concentrations can be compared to other indicators of mobile source activity, such as the ones
discussed below, to determine if correlations exist.
4.3.3 Motor Vehicle Ownership
Another indicator of motor vehicle activity near the monitoring sites is the total number
of vehicles owned by residents in the county where each monitoring site is located, which
includes passenger vehicles, trucks, and commercial vehicles, as well as vehicles that can be
regional in use such as boats or snowmobiles. Actual county-level vehicle registration data were
obtained from each applicable state or local agency, where possible. If data were not available,
vehicle registration data are available at the state-level (FHWA, 2011). The county proportion of
the state population was then applied to the state registration count.
4-36
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The county-level motor vehicle ownership data and the average summed hydrocarbon
concentrations are presented in Table 4-14. As previously discussed, TOOK, SPAZ, and NBIL
have the highest average summed hydrocarbon concentrations, respectively, while GLKY and
UCSD have the lowest. Table 4-14 also shows that SPAZ, PXSS, NBIL, and SPIL have the
highest county-level vehicle ownership of the sites sampling VOCs, while PROK, GLKY, and
UCSD have the lowest. The Pearson correlation coefficient calculated between these two
datasets is 0.46. Although this correlation falls just below the "strong" classification, it does
indicate a positive correlation between hydrocarbon concentrations and vehicle registration.
CELA, which has the highest county-level vehicle ownership of all NMP sites, did not sample
VOCs under the NMP.
The vehicle ownership at the county-level may not be completely indicative of the
ownership in a particular area. As an illustration, for a county with a large city in the middle of
its boundaries and less populated areas surrounding it, the total county-level ownership may be
more representative of areas inside the city limits than in the rural outskirts. Therefore, a vehicle
registration-to-population ratio was developed for each county with a monitoring site. Each ratio
was then applied to the 10-mile population surrounding the sites (provided in the individual state
sections) to estimate a 10-mile vehicle ownership, which is also presented in Table 4-14. Table
4-14 shows that ELNJ, PXSS, and PANJ have the highest 10-mile estimated vehicle ownership
of the sites sampling VOCs, while PROK, GLKY, and UCSD have the lowest. The Pearson
correlation coefficient calculated between the average summed hydrocarbon calculations and the
10-mile vehicle registration estimates is 0.41. While this correlation also falls below the "strong"
classification, it does indicate a positive correlation between hydrocarbon concentrations and the
estimated vehicle registration within a 10-mile radius. CELA, which had the highest 10-mile
estimated vehicle ownership of all NMP sites, did not sample VOCs under the NMP.
Other factors may affect the reliability of motor vehicle ownership data as an indicator of
ambient air monitoring data results:
Estimates of higher vehicle ownership surrounding a monitoring site do not
necessarily imply increased motor vehicle use in the immediate vicinity of a
monitoring site. Conversely, sparsely populated regions often contain heavily
traveled roadways.
4-37
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Emissions sources in the area other than motor vehicles may significantly affect
levels of hydrocarbons in ambient air.
4.3.4 Estimated Traffic Volume
Traffic data for each of the participating monitoring sites were obtained from state and
local agencies, primarily departments of transportation. Most of the traffic counts in this report
reflect AADT, which is "the total volume of traffic on a highway segment for 1 year, divided by
the number of days in the year," and incorporates both directions of traffic (FL DOT, 2007).
AADT counts obtained were based on data from 2002 to 2011, primarily 2009 forward. The
updated traffic values are presented in Table 4-14. The traffic data presented in Table 4-14
represent the most recently available data applicable to the monitoring sites.
There are several limitations to obtaining the AADT near each monitoring site. AADT
statistics are developed for roadways, such as interstates, state highways, or local roadways,
which are managed by different municipalities or government agencies. AADT is not always
available in rural areas or for secondary roadways. For monitoring sites located near interstates,
the AADT for the interstate segment closest to the site was obtained. For other monitoring sites,
the highway or secondary road closest to the monitoring site was used. Only one AADT value
was obtained for each monitoring site. The intersection or roadway chosen for each monitoring
site is discussed in each individual state section (Sections 5 through 28).
Table 4-14 shows that ELNJ, SEW A, and SPIL have the highest daily traffic volumes of
the sites sampling VOCs, while IHSTVT, GLKY, and UCSD have the lowest. For all monitoring
sites (not just those sampling VOCs), the highest daily traffic volume occurs near ELNJ, CELA,
and SEWA. ELNJ is located near Exit 13 on 1-95; CELA is located in downtown Los Angeles;
and SEWA is located in Seattle near the intersection of 1-5 and 1-9. ELNJ has the highest traffic
volume and the seventh highest hydrocarbon average, but SEWA, SPIL, and PXSS, which have
the second, third, and fourth highest traffic volumes, have the 17th, 11th, and 4th highest
hydrocarbon averages, respectively. Again, CELA did not measure VOCs under the NMP. A
Pearson correlation coefficient calculated between the average hydrocarbon calculations and the
traffic counts is 0.28. While this correlation is not a "strong" correlation, it does indicate a
positive correlation between hydrocarbon concentrations and traffic volumes.
4-38
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4.3.5 Vehicle Miles Traveled
Another approach to determine how mobile sources affect urban air quality is to review
VMT. VMT is "the sum of distances traveled by all motor vehicles in a specified system of
highways for a given period of time" (OR DOT, 2012). Thus, VMT values tend to be large (in
the millions). In past NMP reports, daily VMT data from the Federal Highway Administration
(FHWA) were obtained. However, VMT was only available by urban area; thus, no VMT was
available for sites located in rural areas. Beginning with the 2010 NMP, county-level VMT was
obtained from state organizations, primarily departments of transportation. However, these data
are not readily available for all states. In addition, not all states provide this information on the
same level. For example, many states provide VMT for all public roads, while the state of
Colorado provided this information for state highways only. County-level VMT are presented in
Table 4-14, where available.
The sites with the highest county-level VMT, where available, are CELA (Los Angeles
County, CA), PXSS and SPAZ (Maricopa County, AZ), and SPIL and NBIL (Cook County, IL).
The sites with the lowest county-level VMT, where available, are CHSC (Chesterfield County,
SC), GLKY (Carter County, KY), and UCSD (Union County, SD). A Pearson correlation
coefficient calculated between the average summed hydrocarbon concentrations and VMT,
where available, is 0.46, indicating a positive correlation between hydrocarbon concentrations
and county-level VMT. It is important to note that many of the sites with larger VMT did not
measure VOCs under the NMP (such as CELA, RUCA, CAMS 35, and SJJCA). In addition,
county-level VMT were not readily available for Rhode Island.
4.4 Variability Analysis
This section presents the results of the three variability analyses described in
Section 3.4.2.
4.4.1 Coefficient of Variation and Inter-site Variability
The site-specific CVs and the inter-site comparison analyses are discussed together in
this section. Figures 4-la through 4-25a are graphical displays of site-specific CVs (standard
deviation vs. annual average concentration) for the program-level pollutants of interest.
Figures 4-lb through 4-25b are bar graphs depicting the site-specific annual averages overlain on
4-39
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the program-level averages, as discussed in Section 4.1. For each program-level pollutant of
interest, the CV graph is shown first, followed by the inter-site variability graph. The figures are
aligned this way because they tend to complement each other; the data point with the highest
annual average concentration and/or standard deviation in the CV graph is easily identifiable in
the inter-site variability graph. Further, the inter-site variability graphs allow the reader to see
how the individual site-specific annual averages feed into the program-level averages (i.e., if a
specific site(s) is driving the program average). In addition to the standard deviations on the CV
graphs, the confidence intervals provided on the inter-site variability graphs are a further
indication of the amount of variability contained within the site-specific annual averages.
Several items to note about these figures: Some sites do not have annual averages
presented on the inter-site variability graphs because they did not meet the criteria specified in
Section 3.1. These same sites without annual averages on the inter-site variability graphs are not
represented by a data point on the corresponding CV graphs. For the sites sampling metals, the
program-level average for sites collecting PMio samples is presented in green while the program-
level average for sites collecting TSP samples is presented in pink. The annual averages for the
sites sampling only SNMOCs are not included in the graphs for benzene, 1,3-butadiene, or
ethylbenzene.
The CV figures show that few of the pollutants appear to exhibit the "clustering"
discussed in Section 3.4.2. Figure 4-10a for carbon tetrachloride exhibits clustering, or
uniformity in concentrations. Carbon tetrachloride is a pollutant that was used worldwide as a
refrigerant. However, it was identified as an ozone-depleting substance in the stratosphere and its
use was banned at the Kyoto Protocol. This pollutant has a long lifetime in the atmosphere, but
slowly degrades over time. Today, its concentration in ambient air is fairly ubiquitous regardless
of where it is measured. The CVs shown in Figure 4-10a not only support the expected
uniformity (i.e., lack of variability) in "background" concentrations of carbon tetrachloride, but
are also a testament to the representativeness of the data generated under the NMP. Figure 4-1 Ob
supports what is shown in Figure 4-10a. The inter-site variability is relatively low, with the
annual average concentrations of carbon tetrachloride ranging from 0.53 |ig/m3 for GPCO to
0.65 |ig/m3 for SEWA and DEMI. Further, the confidence intervals for all sites shown are less
than ฑ0.07 |ig/m3.
4-40
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Figure 4-13a shows that 1,2-dichloroethane also appears to exhibit clustering. However,
it should be noted that the y-axis scale for the standard deviation is three times larger than the
x-axis scale for the annual average concentration. This indicates that there is a relatively high-
level of variability in the individual concentrations, as supported in Figure 4-13b by the
relatively large confidence intervals shown for every site. In addition, this pollutant was detected
infrequently (only 25 percent of samples) and therefore has many zero substitutions factored into
each annual average, which contributes to both the low range of annual average concentrations
(all less than 0.035 |ig/m3) and the large confidence intervals.
Other pollutants, such as hexchloro-1,3-butadiene and vinyl chloride, exhibit the same
large confidence intervals on the inter-site variability graphs as 1,2-dichloroethane due to a large
number of non-detects and the associate zero substitutions. Hexchloro-1,3-butadiene was
detected in fewer than 10 percent of samples, resulting in a large number of zero substitutions.
With the exception of the sites that did not detect this pollutant, the standard deviations are all
greater than the annual average for each site in Figure 4-17a, as shown by the values along the
x- and y-axes. Further, nearly every site has a relatively large confidence interval shown in
Figure 4-17b. The largest confidence intervals were calculated for SPIL and MWOK; although
these two sites measured the two greatest concentrations of hexachloro-l,3-butadiene
(0.684 |ig/m3 for SPIL and 0.631 |ig/m3 for MWOK), this pollutant was detected only three times
at SPIL and four times at MWOK.
Similarly, vinyl chloride is another infrequently detected pollutant (less than a 7 percent
detection rate) for which the annual averages have large standard deviations in Figure 4-25a
(note how many of the standard deviations are more than twice the corresponding annual
averages) and large confidence intervals in Figure 4-25b. Although the concentrations of vinyl
chloride were at least an order of magnitude less than the concentrations of
hexchloro-1,3-butadiene, nearly half of the vinyl chloride measurements were greater than the
MDL while only two (the high concentrations for MWOK and SPIL) were greater than the MDL
for hexachloro-1,3 -butadiene.
4-41
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Several CVs for the program-level pollutants of interest follow a linear trend line.
Examples of pollutants whose annual average concentrations exhibit this trend include
acenaphthalene, acetaldehyde, benzene, fluorene, hexavalent chromium, lead, naphthalene, and
tetrachloroethylene. This means that as the annual averages increase, so do the standard
deviations, indicating increasing variability. This increased variability is often a result of an
increased range of individual measurements that are used to calculate the annual average. This is
supported by the corresponding inter-site variability graphs for each pollutant. The site-specific
annual averages that extend well above the program-level average concentration for each
pollutant tend to have a wider confidence interval associated with them, indicating a wider range
of measurements and the possible influence of outliers. The annual averages considerably less
than the program-level average concentration tend to have much smaller confidence intervals.
Figures 4-la and 4-lb for acenaphthalene and Figures 4-15a and 4-15b for fluorene are good
examples of this trend. The higher annual averages for sites such as DEMI, NBIL and ROCH
have large confidence intervals associated with them while sites such as CHSC, GLKY, and
UNVT have significantly lower annual averages as well as very small confidence intervals. To
illustrate this point, the range of measured detections of acenaphthene for DEMI was
0.698 ng/m3 to 111 ng/m3 while the range of measurements for GLKY was 0.0793 ng/m3 to
1.02 ng/m3. DEMF sill ng/m3 measureme
acenaphthene measured across the program.
1.02 ng/m3. DEMF sill ng/m3 measurement of acenaphthene was the highest measurement of
Some of the pollutants' annual averages follow a linear pattern, but one of the annual
average concentrations is significantly higher than other annual average concentrations of the
other sites, one of the standard deviations is significantly higher than other sites, or both (such as
benzene, beryllium, and tetrachloroethylene). Figures 4-5a and 4-5b show that the annual
average benzene concentration for TOOK is more than twice the next highest annual average
concentration for this pollutant. A review of TOOK's benzene data shows that all but seven of
TOOK's preprocessed daily measurements (out of 57) were greater than the program-level
average concentration of 0.98 |ig/m3. Thus, concentrations of benzene at TOOK tend to run
higher than at other sites. Figure 4-23a shows that the magnitude of the standard deviation axis is
more than twice the annual average axis for tetrachloroethylene. Figure 4-23b shows that this is
the result of the PXSS data. The maximum concentration measured at PXSS (8.63 |ig/m3) is
more than three times higher than the next highest tetrachloroethylene measurement (2.42 |ig/m3,
4-42
-------
measured at NBIL) and nearly five times higher than the next highest tetrachloroethylene
measurement at PXSS (1.74 |ig/m3). Thus, the annual average concentration of
tetrachloroethylene for PXSS is reflecting the influence of the outlying concentration.
Although many of the other pollutants of interest do not exhibit easily classifiable
clustering or appear to follow a linear pattern, some of them are influenced by one or more data
points that do not fall in line with the others. For example, the larger standard deviation
(1.20 |ig/m3) exhibited for 1,3-butadiene in Figure 4-8a indicates that this particular annual
average is likely influenced by outlier(s). Figure 4-8b shows that this data point represents
OCOK's annual average. Excluding this data point would allow the rest to follow a more linear
trend line. Although this site did not have the highest annual average concentration of
1,3-butadiene, the highest individual measurement of this pollutant across the program was
measured at OCOK (9.51 jig/m3). The next highest measurement of 1,3-butadiene at OCOK was
considerably less (approximately 0.25 |ig/m3). The next highest measurement at the program
level was 2.68 |ig/m3, measured at NBIL.
If the data point that represents SPIL's annual average and standard deviation was
removed and the scales adjusted, the trichloroethylene concentrations would appear to exhibit a
more linear trend, although some clustering would still be shown among the sites with the lowest
annual averages. The annual average trichloroethylene concentration for SPIL
(0.64 ฑ 0.41 |ig/m3) is more than seven times the annual average trichloroethylene concentration
for any other site, as shown in both Figures 4-23 a and 4-23b. If the two highest concentrations
measured at SPIL (those greater than 3 |ig/m3) were removed from the calculation, SPIL's
annual average would still be more than four times the next highest annual average (as calculated
for ELNJ). SPIL's annual average trichloroethylene concentration is discussed in more detail in
Section 4.2.1.
Acrylonitrile appears to exhibit clustering in Figure 4-3 a with the exception of the annual
average concentration for SPIL. The annual average concentration of acrylonitrile for SPIL
(0.77 |ig/m3) is nearly five times greater than the next highest concentration, as shown in
Table 4-9 and Figure 4-3b. Without this data point, the annual average concentrations of
acrylonitrile range from 0.01 |ig/m3 to 0.17 |ig/m3. However, this pollutant was detected in fewer
4-43
-------
than 25 percent of samples, resulting in a large number of zero substitutions; thus the standard
deviations for this pollutant tended to be rather large, as compared to the annual averages
themselves. This is evident by the number of sites whose standard deviations are larger than their
corresponding annual averages in Figure 4-3a.
Chloroform appears to exhibit clustering in Figure 4-1 la. However, chloroform was
detected in fewer than 60 percent of samples. This can yield relatively low annual averages and
standard deviations, due in part to the substitution of zeros for many non-detects. If the data
point that represents NBIL's annual average, which is more than seven times greater than the
next highest annual average, was removed from Figure 4-1 la and the scales adjusted, most of the
chloroform concentrations still exhibit clustering. However, the three sites (DEMI, PXSS, and
S4MO) with annual averages just above and just below the program-level average concentration
of chloroform (0.39 |ig/m3) stand out more, as they do in Figure 4-1 Ib. While S4MO's annual
average concentration is less than the annual averages for DEMI and PXSS, S4MO's standard
deviation (1.50 |ig/m3) is relatively large compared to its annual average concentration
(0.35 ฑ 0.40 |ig/m3). This is due to one particularly high measurement (11.5 |ig/m3), skewing the
data. This is illustrated not only by the confidence intervals shown in Figure 4-1 Ib but also by
the site-specific annual average concentration comparison for chloroform shown in Table 4-9.
4-44
-------
Figure 4-1 a. Coefficient of Variation Analysis of Acenaphthene Across 23 Sites
I15
B
.a
I
1
3
y=1.2448x-1.1506
R1 = 0.9163
6 8 10
Annual Average Concentration (ng/m3)
Figure 4-lb. Inter-Site Variability for Acenaphthene
.a
1 10
s
3
n
il
BOMA BTUT CAMS CELA CH5C DEMI GLKY GPCO MONY NBIL PRRI PX5S RIVA ROCH RUCA S4MO SDGA 5EWA 5JJCA 5KFL 5YFL UNVT WADC
35
Monitoring Site
Program Average
nSite-SpecificAnnual Average
4-45
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Figure 4-2a. Coefficient of Variation Analysis of Acetaldehyde Across 24 Sites
y=0.6977x-0.3503
ff- 0.7359
n o
1 1.5 2
Annual Average Concentration (
Figure 4-2b. Inter-Site Variability for Acetaldehyde
Monrtoring Site
Program Average
DSite-Specific Annual Average
4-46
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Figure 4-3a. Coefficient of Variation Analysis of Acrylonitrile Across 22 Sites
y=0.5078x +0.0733
R! = 0.6244
oo
0.3 0.4 0.5
Annual Average Concentration (
Figure 4-3b. Inter-Site Variability for Acrylonitrile
"E
JO.6
E
a
ซ 0.5
s
3
&0.4
Jฑt
?
Monitoring Site
Program Average D Site-Specific Annual Average
4-47
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Figure 4-4a. Coefficient of Variation Analysis of Arsenic Across 14 Sites
y=0.6659x + 0.0602
ซ.'- 0.5519
I 0.3
y=0.2846x + 0.0947
R2 = 0.5903
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Annual Average Concentration (ng/m3)
O PM10 O TSP Linear(PMlO) Linear(TSP)
Figure 4-4b. Inter-Site Variability for Arsenic
S
E
a
E 0.6
I
3
BOMA BTUT GLKY NBIL PAFL PXS5 S4MO SEWA SJJCA UNVT MWOK OCOK PROK TMOK TOOK
Monitoring Site
D Program PMlOAverage
D Program TSP Average
D Site-Specific Annual Average
4-48
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Figure 4-5a. Coefficient of Variation Analysis of Benzene Across 23 Sites
y= 1.0979X-0.4515
R! = 0.937
"I"
O
o
1.5 2 2.5
Annual Average Concentration (
Figure 4-5b. Inter-Site Variability for Benzene
Hh
Monitoring Site
Program Average D Site-Specific Annual Average
4-49
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Figure 4-6a. Coefficient of Variation Analysis of Benzo(a)pyrene Across 23 Sites
I-
|
I
y=0.945Bxt 0.034
R* = 0.5462
0.1 0.15
Annual Average Concentration (ng/m3)
Figure 4-6b. Inter-Site Variability for Benzo(a)pyrene
_ 0.2
|
a
E
g 0.15
I
3
BOMA BTUT CAMS CELA CHSC DEMI GLKY GPCO MONY NBIL PRRI PXSS RIVA ROCH RUCA S4MO SDGA SEWA SJJCA SKFL SYFL UNVT WADC
35
Monitoring Site
Program Average
nsite-SpecificAnnual Average
4-50
-------
Figure 4-7a. Coefficient of Variation Analysis of Beryllium Across 14 Sites
y=1.2502x + 0.0024
R! = 0.8486
I:
e
.a
op--
V=0.8987jt-0.0052
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05
Annual Average Concentration (ng/m5)
O PM10 O TSP Linear (PM10) Linear(TSP)
Figure 4-7b. Inter-Site Variability for Beryllium
I
=
\
I
r
BOMA BTUT GLKY NBIL PAFL PXSS S4MO SEWA SJJCA UNVT MWOK OCOK PROK TMOK TOOK
Monitoring Site
D Program PM10 Average
D Program TSP Average
D Site-Specific Annual Average
4-51
-------
Figure 4-8a. Coefficient of Variation Analysis of 1,3-Butadiene Across 23 Sites
V=l.S921x- 0.0484
ff= 0.234
0.15 0.2
Annual Average Concentration (n
Figure 4-8b. Inter-Site Variability for 1,3-Butadiene
"E
1
E
.a
s
3
S
0.1 -
I
1
* d
i
1
/
[ฑ
c/0<
+
?
-------
Figure 4-9a. Coefficient of Variation Analysis of Cadmium Across 14 Sites
y=0.7S72x+0.0072
R; = 0.9061
,-' v=10236x-0.052
R= = 0.7595
0.2 0.3 0.4
Annual Average Concentration (ng/m3)
O PM10 O TSP Linear(PMlO) Linear(TSP)
Figure 4-9b. Inter-Site Variability for Cadmium
T
E
a
= 0.4
s
3
} 0.3
BOMA BTUT GLKY NBIL PAFL PXS5 S4MO SEWA SJJCA UNVT MWOK OCOK PROK TMOK TOOK
Monitoring Site
D Program PM10 Average
D Program TSP Average
D Site-Specific Annual Average
4-53
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Figure 4-10a. Coefficient of Variation Analysis of Carbon Tetrachloride Across 23 Sites
0.2 0.3 0.4
Annual Average Concentration (\.
\ O
Y=-0.3B7Sx + 0.3687
R! = 0.1949 Q V!
^>V
O o
O O O
Figure 4-1 Ob. Inter-Site Variability for Carbon Tetrachloride
^
.s
S 04
I
3
&
rfl
-h
Monitoring S te
Program Average
DSite-SpecificAnnual Average
4-54
-------
Figure 4-lla. Coefficient of Variation Analysis of Chloroform Across 23 Sites
y= 1.3197X-0.0043
Rz = 0.9761
2345
Annual Average Concentration (ujj/m3)
Figure 4-1 Ib. Inter-Site Variability for Chloroform
^ ^
^ ซ?
Monitoring Site
Program Average
D Site -Specific Annual Average
4-55
-------
Figure 4-12a. Coefficient of Variation Analysis of/J-Dichlorobenzene Across 23 Sites
&
E 0.2
Y=0.9855x +0.0091
R= = 0.6357
0.1 0.15
Annual Average Concentration (
Figure 4-12b. Inter-Site Variability for/7-Dichlorobenzene
rfi
-------
Figure 4-13a. Coefficient of Variation Analysis of 1,2-Dichloroethane Across 23 Sites
i
y = 1.4603x +0.0109
RJ = 0.3805
0.015 0.02 0.025
Annual Average Concentration (i^g/m3)
Figure 4-13b. Inter-Site Variability for 1,2-Dichloroethane
_ 0.04
i
1
c
a
Monitoring Site
Program Average
DSite-SpecificAnnual Average
4-57
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Figure 4-14a. Coefficient of Variation Analysis of Ethylbenzene Across 23 Sites
.2 0.8
e
i
5 0.6
V=0.7195x
R' = 0.2712
O O
0.4 0.6 0.8
Annual Average Concentration ((^g/m5)
Figure 4-14b. Inter-Site Variability for Ethylbenzene
1-
E
a
ฃ o.s
s
s
Hh
rh
Monitoring Site
Program Average
DSite-SpecificAnnual Average
4-58
-------
Figure 4-15a. Coefficient of Variation Analysis of Fluorene Across 23 Sites
y=1.259x-2.0842
R! = 0.8677
I
&
6 S 10
Annual Average Concentration (ng/m3)
Figure 4-15b. Inter-Site Variability for Fluorene
.S
e
S 10
n
rh
^^
rir
BOMA BTUT CAMS CELA CHSC DEMI GLKY GPCO MONY NBIL PRRI PXSS RIVA ROCH RUCA S4MO SDGA SEWA SJJCA SKFL SYFL UNVT WADC
35
Monitoring Site
Program Average
D Site-Specific Annual Average
4-59
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Figure 4-16a. Coefficient of Variation Analysis of Formaldehyde Across 24 Sites
ฅ= 0.854Ix-0.5856
R! = 0.5261
1.5 2 2.5 3
Annual Average Concentration (|Jg/n
Figure 4-16b. Inter-Site Variability for Formaldehyde
_4
^E
1
c
.e
Monitoring Site
Program Average
DSite-SpecificAnnual Average
4-60
-------
Figure 4-17a. Coefficient of Variation Analysis of Hexachloro-l,3-butadiene Across 23 Sites
0.01 0.015
Annual Average Concentration (ug/m5)
Figure 4-17b. Inter-Site Variability for Hexachloro-l,3-butadiene
_ 0.03
i
1
g 0.025
C
I
3 0.02
Program Average
- ^ ,* ฃ
-------
Figure 4-18a. Coefficient of Variation Analysis of Hexavalent Chromium Across 22 Sites
J
B
.2
I ฐ
&
e
i
K
V=0.5671x +0.0051
R! = 0.8347
0.03 0.04
Annual Average Concentration (ng/m3)
Figure 4-18b. Inter-Site Variability for Hexavalent Chromium
_ 0.06
I
3 0.04
il
BOMA BTUT CAMS CAMS CHSC DEMI GLKY GPCO HOWI MONY NBIL PRRI PXSS RIVA ROCH S4MO SDGA SEWA SKFL SYFL UNVT WADC
35 85
Monitoring Site
Program Average
nsite-SpecificAnnual Average
4-62
-------
Figure 4-19a. Coefficient of Variation Analysis of Lead Across 14 Sites
r
y=0.6267x + 0.3349
R! = 0.8648
o ,,-6
00
y=0.6718x- 0.7655
R! = 0.995
468
Annual Average Concentration (ng/m3)
O PM10 O TSP Linear(PMlO) Linear(TSP)
Figure 4-19b. Inter-Site Variability for Lead
\
= s
I
1
I'
fn rf
BOMA BTUT GLKY NBIL PAFL PXSS S4MO 5EWA SJJCA UNVT MWOK OCOK PROK TMOK TOOK
Monitoring Site
D Program PMlOAverage
D Program TSP Average
D Site-Specific Annual Average
4-63
-------
Figure 4-20a. Coefficient of Variation Analysis of Manganese Across 14 Sites
!
y= 1.9349X-4.9954
R' = 0.7189
y=0.5592x
R== 0.994
0--"CT
15 20
Annual Average Concentration (ng/m3)
O PM10 O TSP Unear(PMlO) Linear(TSP)
Figure 4-20b. Inter-Site Variability for Manganese
r
E
.2
E 20
I
3
I15
BOMA BTUT GLKY NBIL PAFL PX5S S4MO SEW A SJJCA UNVT MWOK OCOK PROK TMOK TOOK
Monitoring Site
D Program PMlOAverage
D Program TSP Average
D Site-Specific Annual Average
4-64
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Figure 4-21a. Coefficient of Variation Analysis of Naphthalene Across 23 Sites
"i,.
B
a
i
3 60
ฃ
y=0.6549x +2.2998
60 BO 100 120
Annual Average Concentration (ng/m5)
140 160
Figure 4-21b. Inter-Site Variability for Naphthalene
Concentration (ng/m3)
H1 I-1 H1 H1 I-1 W
S S ฃ S S g
| so
ฅ
60 -
40
20
0
T
1
BO MA
i
n
n
lr
T
T
ill
BTUT CAMS CELA CHSC DEMI GLKY GPCO MONY NBIL PRRI PXSS RIVA ROCH RUC-A S4MO SDGA SEWA SJJCA SKFL
i
SYFL
fl
UNVT WADC
35
Monitoring Site
Pro|
ram Average
DSite-SpecificAnnual Average
4-65
-------
Figure 4-22a. Coefficient of Variation Analysis of Nickel Across 14 Sites
1"
e
I i
S
|
1 o.s
y=0.9749x-0.3606
R! = 0.8149
o
o-'''
y=0.4865x-0.0142
R; = 0.6739
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 l.S
Annual Average Concentration (ng/m3)
O PM10 O TSP Linear(PMlO) Linear(TSP)
Figure 4-22b. Inter-Site Variability for Nickel
BOMA BTUT GLKY NBIL PAFL PXS5 S4MO SEWA SJJCA UNVT MWOK OCOK PROK TMOK TOOK
Monitoring Site
D Program PM10 Average
D Program TSP Average
D Site-Specific Annual Average
4-66
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Figure 4-23a. Coefficient of Variation Analysis of Tetrachloroethylene Across 23 Sites
1
y=1.6099x-0.071
R! = 0.8417
0.2 0.3
Annual Average Concentration (
Figure 4-23b. Inter-Site Variability for Tetrachloroethylene
,-.0.6
i
1
I 0.5
i
50.4
Monitoring Site
Program Average
DSite-SpecificAnnual Average
4-67
-------
Figure 4-24a. Coefficient of Variation Analysis of Trichloroethylene Across 23 Sites
1,
"E 0.8
1
V= 2.3963X +0.0118
R'- 0.9665
0.2 0.3 0.4 0.5
Annual Average Concentration (ug/m5)
Figure 4-24b. Inter-Site Variability for Trichloroethylene
_0.8
1
JฑL
Program Average
Monitoring Site
D Site-Specific Annual Average
4-68
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Figure 4-25a. Coefficient of Variation Analysis of Vinyl Chloride Across 23 Sites
Jo.oos
e
a
I
y=2.6421x
R2 = 0.9021
0 i J
0
0.001 0.0015 0.002 0.0025
Annual Average Concentration (ug/m3)
Figure 4-25b. Inter-Site Variability for Vinyl Chloride
1
7 0.004
a
I
3 o.oos
Monitoring Site
Program Average
D Site -Specific Annual Average
4-69
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4.4.2 Quarterly Variability Analysis
Figures 4-26 through 4-50 provide a graphical display of the site-specific quarterly
average concentrations for each of the program-level pollutants of interest. Quarterly averages
are calculated based on the criteria specified in Section 3.1. If the pollutant of interest has a
corresponding ATSDR Intermediate MRL, as defined in Section 3.3, then this value is indicated
on the graph and is plotted where applicable. The National Ambient Air Quality Standard
(NAAQS) for lead (TSP) is a 3-month standard. Because this time period aligns well with the
quarterly averages presented in this section, the NAAQS for lead (TSP) is also provided in
Figure 4-44a and 4-44b. Note that the scales on the PMio and TSP graphs are the same for a
given speciated metal.
Data gaps, or missing quarterly averages, in the figures for the pollutants of interest can
be attributed to two reasons. First, some of the program-wide pollutants of interest were
infrequently detected in some quarters and thus have a quarterly average concentration of zero as
a result of the substitution of zeros for non-detects. One example of this is Figure 4-28 for
acrylonitrile. This pollutant was infrequently detected (300 measured detections out of 1,281
valid samples); of the 85 possible quarterly averages of this pollutant, 22 of them are zero. Thus,
few quarterly averages appear in Figure 4-28. Further, most of the remaining quarterly averages
have relatively few measurements and include many zero substitutions for non-detects, resulting
in relatively low quarterly averages. (Although this pollutant was detected in only 23 percent of
VOC samples collected, its risk screening value is relatively low; thus, all 300 measured
detections of this pollutant failed screens.)
Another reason for data gaps in the figures is due to the sampling duration of each site.
Some sites started late or ended early, which may result in a lack of quarterly averages. For
example, benzene is almost always detected in VOC samples, thus the gaps in Figure 4-30 are
primarily due to sampling duration. PANJ stopped sampling VOCs in May 2011; thus, the third
and fourth quarterly averages are blank. Because the criteria in Section 3.1 require a site to have
75 percent of the possible samples within a quarter (12 for a site sampling on a l-in-6 day
schedule), PAJN could not get a quarterly average for the second quarter because it did not
sample long enough within that quarter. Therefore, the only quarterly average that could be
calculated for PANJ was for the first quarter.
4-70
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Some pollutants of interest, such as acetaldehyde, benzene, carbon tetrachloride,
ethylbenzene, formaldehyde, and naphthalene, were detected year-round. Comparing the
quarterly averages for sites with four valid quarterly averages in a year may reveal a trend for
these pollutants. For example, formaldehyde averages tended to be highest in the third quarter, as
shown in Figure 4-41, with 18 of the 30 sites sampling formaldehyde (and have quarterly
averages) exhibiting the highest quarterly average during July through September. Thus, it
appears that formaldehyde concentrations tend to be highest during the summer months.
Conversely, benzene averages tended to be higher during the first quarter followed by the fourth
quarter, or the colder months, as shown in Figure 4-30. The seasonal behavior of benzene and
formaldehyde suggests the influence of reformulated gasoline (RFG) because the benzene
content is typically lowered during warmer periods (i.e., summer and spring). Refineries
typically begin production of RFG during the spring and end in the autumn. Additionally,
methyl tert-buty\ ether (MTBE) is often used as an RFG additive in fuels to replace the lowered
benzene content. Research has shown that the combustion of fuels containing MTBE leads to the
secondary production of formaldehyde. Thus, while benzene concentrations decrease during the
summer months, formaldehyde concentrations may increase if MTBE is used in the gasoline
blend.
Other notable trends include benzo(a)pyrene and 1,3-butaidene with higher
concentrations in the first and fourth quarters; acenaphthene and fluorene with higher
concentrations in the third quarter; and 1,2-dichloroethane with higher concentrations in the
second and fourth quarters. Arsenic tended to be highest during the fourth quarter for eight of
the nine sites sampling PMio metals year-round and four of the five sites sampling TSP metals (a
fourth quarter average could not be calculated for MWOK because it did not meet the
completeness criteria).
Other notable trends may also be revealed in these graphs. Figure 4-38 for
1,2-dichlorethane shows that most of the measured detections of this pollutant were measured
during the second and fourth quarter averages of 2011, as indicated by the red (second quarter)
and purple (fourth quarter) bars. Over 50 percent of the measured detections were measured
during the fourth quarter and another 28 percent were measured during the second quarter.
Figure 4-50 for vinyl chloride shows that this pollutant was infrequently detected, as many sites
4-71
-------
have fewer than four quarterly averages shown, even though they sampled year-round and met
the completeness criteria. Note that BTUT, RUVT, and SPAZ did not detect this pollutant at all.
The quarterly average comparison also allows for the identification of sites with
unusually high concentrations of the pollutants of interest compared to other sites and when
those high concentrations were measured. This is evident in Figures 4-28, 4-30, 4-32a, 4-33,
4-36, and 4-49 for acrylonitrile, benzene, beryllium, 1,3-butadiene, chloroform, and
trichloroethylene, respectively, to name a few. For example, Figure 4-36 shows that the quarterly
averages of chloroform for NBIL are significantly higher than for other sites sampling VOCs, as
most of the other bars are barely visible on the graph. Figure 4-49 shows that the quarterly
averages of trichloroethylene for SPIL are significantly higher than for other sites sampling
VOCs. Figure 4-32a and 4-32b show that PXSS's third quarter average concentration of
beryllium is significantly higher than this site's other the quarterly averages as well as all other
sites sampling speciated metals (both PMi0 and TSP). Conversely, these graphs may also reveal
when there is very little variability in the quarterly averages across other sites. Figure 4-35 for
carbon tetrachloride shows that the quarterly averages of this pollutant did not vary significantly
across the sites. Other pollutants may not exhibit such trends.
These graphs also show that only 10 of the 25 program-level pollutants of interest have
ATSDR Intermediate MRLs. For the 10 that do, the quarterly average concentrations are
significantly less than their respective ATSDR Intermediate MRLs, generally by an order of
magnitude or more, which is also discussed in Section 4.2.2. In all 10 cases, the scale on the
graph is well below the ATSDR Intermediate MRL.
4-72
-------
Figure 4-26. Comparison of Average Quarterly Acenaphthene Concentrations
BOMA BTUT CAMS CELA CHSC DEMI GLKY GPCO MONY NBIL PRRI PXSS RIVA ROCH RUCA S4MO SDGA SEWA SJJCA SKFL SYFL UNVT WADC
11st Quarter
Monitoring Site
2nd Quarter 3rd Quarter 14th Quarter
-------
Figure 4-27. Comparison of Average Quarterly Acetaldehyde Concentrations
11st Quarter
Monitoring Site
1 2nd Quarter 3rd Quarter
4th Quarter
-------
Figure 4-28. Comparison of Average Quarterly Acrylonitrile Concentrations
0.9
0.8
0.7
5 0.6
2
Q 0.5
&
2
| 0.4
&
v
0.3
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter B4th Quarter
-------
Figure 4-29a. Comparison of Average Quarterly Arsenic (PMio) Concentrations
BOMA BTUT GLKY NBIL PAFL PXSS S4MO
Monitoring Site
IstQuarter B2nd Quarter B3rd Quarter
SEWA
SJJCA
14th Quarter
UNVT
-------
Figure 4-29b. Comparison of Average Quarterly Arsenic (TSP) Concentrations
MWOK
OCOK
PROK
Monitoring Site
TMOK
TOOK
11st Quarter
12nd Quarter
3rd Quarter
14th Quarter
-------
Figure 4-30. Comparison of Average Quarterly Benzene Concentrations
J^.
I
oo
ATSDRIntermediateMRL=20
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter B4th Quarter
-------
Figure 4-31. Comparison of Average Quarterly Benzo(a)pyrene Concentrations
BOMA BTUT CAMS CELA CHSC DEMI GLKY GPCO MONY NBIL PRRI PXSS RIVA ROCH RUCA S4MO SDGA SEWA SJJCA SKFL SYFL UNVT WADC
35
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter B4th Quarter
-------
Figure 4-32a. Comparison of Average Quarterly Beryllium (PMio) Concentrations
0.12
oo
o
BOMA
BTUT
11st Quarter
GLKY
NBIL
S4MO
PAFL PXS5
Monitoring Site
2nd Quarter B3rd Quarter
SEWA
5JJCA
14th Quarter
UNVT
-------
Figure 4-32b. Comparison of Average Quarterly Beryllium (TSP) Concentrations
oo
0.12
0.1
Is0-08
.a
+ri
2
4-1
c
i
3 3.06
I
0.04
0.02
MWOK
OCOK
PROK
Monitoring Site
TMOK
TOOK
11st Quarter
12nd Quarter
3rd Quarter
14th Quarter
-------
Figure 4-33. Comparison of Average Quarterly 1,3-Butadiene Concentrations
oo
to
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter
4th Quarter
-------
Figure 4-34a. Comparison of Average Quarterly Cadmium (PMio) Concentrations
oo
BOMA BTUT GLKY NBIL
IstQuarter
PAFL PXSS
Monitoring Site
2nd Quarter B3rd Quarter
S4MO SEWA SJJCA UNVT
14th Quarter
-------
Figure 4-34b. Comparison of Average Quarterly Cadmium (TSP) Concentrations
oo
.a
s
2
0.1
6E-16
-0.1
11st Quarter
Monitoring Site
12nd Quarter B3rd Quarter B4th Quarter
-------
Figure 4-35. Comparison of Average Quarterly Carbon Tetrachloride Concentrations
oo
ATSDRIntermediate MRL= 200
11st Quarter
Monitoring Site
1 2nd Quarter 3rd Quarter
4th Quarter
-------
Figure 4-36. Comparison of Average Quarterly Chloroform Concentrations
oo
14
12
JTlO
I 8
I
I
ฃ
i ATSDRIntermediateMRL=200 ng/m3
! ...j
1st Quarter
Monitoring Site
2nd Quarter 3rd Quarter
4th Quarter
-------
Figure 4-37. Comparison of Average Quarterly /7-Dichlorobenzene Concentrations
oo
: ATSDRIntermediate MRL=1,000 |ag/m3
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter B4th Quarter
-------
Figure 4-38. Comparison of Average Quarterly 1,2-Dichloroethane Concentrations
oo
oo
11st Quarter
Monitoring Site
12nd Quarter B3rd Quarter
4th Quarter
-------
Figure 4-39. Comparison of Average Quarterly Ethylbenzene Concentrations
oo
VO
ATSDR Intermediate MRL= 9,000 ug/m3
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter B4th Quarter
-------
Figure 4-40. Comparison of Average Quarterly Fluorene Concentrations
J^.
I
o
BOMA BTUT CAMS CELA CHSC DEMI GLKY GPCO MONY NBIL PRRI PXSS RIVA ROCH RUCA S4MO SDGA SEWA SJJCA SKFL SYFL UNVT WADC
35
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter B4th Quarter
-------
Figure 4-41. Comparison of Average Quarterly Formaldehyde Concentrations
ATSDRIntermediateMRL =
11st Quarter
Monitoring Site
1 2nd Quarter 3rd Quarter
4th Quarter
-------
Figure 4-42. Comparison of Average Quarterly Hexachloro-l,3-butadiene Concentrations
0.06
VO
to
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter
4th Quarter
-------
Figure 4-43. Comparison of Average Quarterly Hexavalent Chromium Concentrations
0.09
0.08
ATSDR Intermediate MRL= 300 ng/m3
o.oi
BOMA BTUT CAMS CAMS CHSC DEMI GLKY GPCO HOWI MONY NBIL PRRI PXSS RIVA ROCH S4MO SDGA SEWA SKFL SYFL UNVT WADC
35 85
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter 4th Quarter
-------
Figure 4-44a. Comparison of Average Quarterly Lead (PMio) Concentrations
12
;-"
i NAAQS for Lead = 150 ng/m3
BOMA
BTUT
GLKY
11st Quarter
NBIL PAFL PXSS S4MO
Monitoring Site
2nd Quarter B3rd Quarter
SEWA
SJJCA
14th Quarter
UNVT
-------
Figure 4-44b. Comparison of Average Quarterly Lead (TSP) Concentrations
12
10
: NAAQS for Lead = 150 ng/m3
.a
4-1
2
MWOK
OCOK
PROK
Monitoring Site
TMOK
TOOK
11st Quarter
12nd Quarter
3rd Quarter
14th Quarter
-------
Figure 4-45a. Comparison of Average Quarterly Manganese (PMio) Concentrations
BOMA
BTUT
GLKY
11st Quarter
NBIL PAFL PXSS S4MO
Monitoring Site
2nd Quarter B3rd Quarter
SEWA
SJJCA
14th Quarter
UNVT
-------
Figure 4-45b. Comparison of Average Quarterly Manganese (TSP) Concentrations
MWOK
OCOK
PROK
Monitoring Site
TMOK
TOOK
11st Quarter
12nd Quarter
3rd Quarter
14th Quarter
-------
Figure 4-46. Comparison of Average Quarterly Naphthalene Concentrations
250
VO
oo
BOMA BTUT CAMS CELA CHSC DEMI GLKY GPCO MONY NBIL PRRI PXSS RIVA ROCH RUCA S4MO SDGA SEWA SJJCA SKFL SYFL UIWT WADC
35
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter 4th Quarter
-------
Figure 4-41 a. Comparison of Average Quarterly Nickel (PMio) Concentrations
3.5
VO
0.5
ATSDRIntermediate MRL= 200 ng/m3
BOMA BTUT GLKY NBIL PAFL PXSS S4MO
Monitoring Site
IstQuarter B2nd Quarter B3rd Quarter
5EWA
SJJCA
14th Quarter
UNVT
-------
Figure 4-47b. Comparison of Average Quarterly Nickel (TSP) Concentrations
3.5
O
O
ATSDRIntermediate MRL= 200 ng/mE
MWOK
OCOK
PROK
Monitoring Site
TMOK
TOOK
11st Quarter
12nd Quarter
3rd Quarter
14th Quarter
-------
Figure 4-48. Comparison of Average Quarterly Tetrachloroethylene Concentrations
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter B4th Quarter
-------
Figure 4-49. Comparison of Average Quarterly Trichloroethylene Concentrations
o
to
ATSDR Intermediate MRL = 500
11st Quarter
Monitoring Site
12nd Quarter B3rd Quarter
4th Quarter
-------
Figure 4-50. Comparison of Average Quarterly Vinyl Chloride Concentrations
J^.
I
o
0.009
O.OOS
ATSDRIntermediate MRL= 80
11st Quarter
Monitoring Site
12nd Quarter 3rd Quarter
4th Quarter
-------
4.5 Greenhouse Gases
Table 4-15 presents the program-level average concentrations for the 10 GHGs measured
using Method TO-15, in descending order by GWP. As shown, most of the GHGs were detected
in nearly every sample collected (a total 1,281 valid VOC samples). Chloroform, bromomethane,
and 1,1,1-trichloroethane were the only pollutants detected in less than 95 percent of VOC
samples collected, although even these were detected in greater than 50 percent of samples.
Dichlorodifluoromethane and dichlorotetrafluoroethane have the highest GWPs of the GHGs
measured by Method TO-15 (10,900 and 10,000 respectively), while bromomethane and
dichloromethane have the lowest GWPs (5 and 8.7, respectively). Dichloromethane has the
highest program-level average concentration among the GHGs measured, although the
associated confidence interval indicates that this concentration is likely influenced by outliers. A
review of the data shows that a single site contributed to this high average concentration. Three
concentrations of this pollutant greater than 100 |ig/m3 were measured at BTUT (ranging from
175 |ig/m3 to 349 |ig/m3). An additional three concentrations greater than 20 |ig/m3 were
measured at BTUT (ranging from 22.4 |ig/m3 to 70 |ig/m3). Besides dichloromethane, only three
additional GHGs shown in Table 4-15 have program-level average concentrations greater than
1 |ig/m3: dichlorodifluoromethane, trichlorofluoromethane, and chloromethane.
4-104
-------
Table 4-15. Greenhouse Gases Measured by Method TO-15
Pollutant
Dichlorodifluoromethane
Dichlorotetrafluoroethane
Trichlorotrifluoroethane
Trichlorofluoromethane
Carbon Tetrachloride
1,1,1 -Trichloroethane
Chloroform
Chloromethane
Dichloromethane
Bromomethane
Global
Warming
Potential1
(100 yrs)
10,900
10,000
6,130
4,750
1,400
146
31
13
8.7
5
Total # of
Measured
Detections
1,281
1,241
1,281
1,281
1,279
1,096
756
1,281
1,264
737
2011
Program
Average
(Hg/m3)
2.75
ฑ0.02
0.13
ฑ<0.01
0.74
ฑ0.01
1.58
ฑ0.02
0.60
ฑ0.01
0.05
ฑ<0.01
0.39
ฑ0.11
1.26
ฑ0.01
3.51
ฑ2.41
0.04
ฑ<0.01
:GWPs presented here are from the Intergovernmental Panel on Climate Change
(IPCC) Fourth Assessment Report (AR4) (IPCC, 2012).
4-105
-------
5.0 Sites in Arizona
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS and UATMP sites in Arizona, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
5.1 Site Characterization
This section characterizes the Arizona monitoring sites by providing geographical and
physical information about the location of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
The Arizona monitoring sites are located in Phoenix, Arizona. Figures 5-1 and 5-2 are
composite satellite images retrieved from ArcGIS Explorer showing the monitoring sites in their
urban locations. Figure 5-3 identifies nearby point source emissions locations by source
category, as reported in the 2008 NEI for point sources. Note that only sources within 10 miles
of the sites are included in the facility counts provided in Figure 5-3. A 10-mile boundary was
chosen to give the reader an indication of which emissions sources and emissions source
categories could potentially have a direct effect on the air quality at the monitoring sites. Further,
this boundary provides both the proximity of emissions sources to the monitoring sites as well as
the quantity of such sources within a given distance of the sites. Sources outside the 10-mile radii
are still visible on the map, but have been grayed out in order to show emissions sources just
outside the boundary. Table 5-1 provides supplemental geographical information such as land
use, location setting, and locational coordinates.
5-1
-------
Figure 5-1. Phoenix, Arizona (PXSS) Monitoring Site
to
-------
Figure 5-2. South Phoenix, Arizona (SPAZ) Monitoring Site
-------
Figure 5-3. NEI Point Sources Located Within 10 Miles of PXSS and SPAZ
112'25'CTW 112'2Q'0*W
112-10'0-W 112'5'Q-W
Legend
PXSS NATTS site
Note: Due to facili'.v density and collocation, the total facilities
displayed may not represent a\\ facilities within the area of interest.
10 mile radius
jjf SPAZ UATMP site County boundary
Source Category Group (No. of Facilities)
fi Aerospace/Aircraft Manufacturing (1)
4> Aircraft Operations (39)
c Chemical Manufacturing (1)
* Electricity Generation via Combustion (4)
-& Flexible Polyurethane Foam Production (1 )
R Furniture Plant (3)
? Miscellaneous Commercial/Industrial (4)
M Miscellaneous Manufacturing (1)
R Rubber and Miscellaneous Plastics Products (1 )
5-4
-------
Table 5-1. Geographical Information for the Arizona Monitoring Sites
Site
Code
PXSS
SPAZ
AQS Code
04-013-9997
04-013-4003
Location
Phoenix
Phoenix
County
Maricopa
Maricopa
Micro- or
Metropolitan
Statistical Area
Phoenix-Mesa-
Glendale, AZ
MSA
Phoenix-Mesa-
Glendale, AZ
MSA
Latitude
and
Longitude
33.503731,
-112.095809
33.40316,
-112.07533
Land Use
Residential
Residential
Location
Setting
Urban/City
Center
Urban/City
Center
Additional Ambient Monitoring Information1
Haze, CO, SO2, NO, NO2, NOX, PAMS, O3,
Meteorological parameters, PM10, PM2 5, PM Coarse,
PM2 5 Speciation.
CO, PAMS, O3, Meteorological parameters, PM2 5,
PM10,PM Coarse.
:Data for additional pollutants are reported to AQS for these sites (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this report.
BOLD ITALICS = EPA-designated NATTS Site
-------
PXSS is located in central Phoenix. Figure 5-1 shows that PXSS is located in a highly
residential area on North 17th Avenue. The Grand Canal is shown along the bottom of
Figure 5-1. The monitoring site is approximately three-quarters of a mile east of 1-17 and 2 miles
north of I-10. Figure 5-2 shows that SPAZ is located near the intersection of West Tamarisk
Avenue and South Central Avenue in South Phoenix. SPAZ is bounded on the west side by
residential properties and commercial properties on the east side. SPAZ is located approximately
1 mile south of 1-17.
SPAZ and PXSS are located approximately 7 miles apart. The majority of emissions
sources are located between the sites, to the south of PXSS and north of SPAZ, as shown in
Figure 5-3. The source category with the greatest number of emissions sources near these
monitoring sites is the aircraft operations source category, which includes airports as well as
small runways, heliports, or landing pads. The emissions source nearest PXSS is a landing strip
at a hospital while the source nearest SPAZ is a landing strip at a police station.
Table 5-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Arizona monitoring sites. Table 5-2 includes county-level
population and vehicle registration information. Table 5-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 5-2 also
contains traffic volume information for each site. Finally, Table 5-2 presents the county-level
daily VMT for Maricopa County.
5-6
-------
Table 5-2. Population, Motor Vehicle, and Traffic Information for the Arizona Monitoring
Sites
Site
PXSS
SPAZ
Estimated
County
Population1
3,880,244
County-level
Vehicle
Registration2
3,776,819
Vehicles per
Person
(Registration:
Population)
0.97
Population
within 10
miles3
1,350,735
848,821
Estimated
10-mile
Vehicle
Ownership
1,314,732
826,196
Annual
Average
Daily
Traffic4
184,000
128,000
County-
level Daily
VMT5
89,448,000
1 County-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2 County-level vehicle registration reflects 2011 data from the Arizona DOT (AZ DOT, 201 la)
3 10-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4 AADT reflects 2010 data from the Arizona DOT (AZ DOT, 2010)
5 County-level VMT reflects 2010 data for all public roads from the Arizona DOT (AZ DOT, 201 Ib)
BOLD ITALICS = EPA-designated NATTS Site
Observations from Table 5-2 include the following:
Maricopa County has the fourth highest county-level population and second highest
county-level vehicle registration compared to other counties with NMP sites.
The vehicle-per-person ratio is just less than one vehicle per person. This ratio falls
within the top third compared to other NMP sites.
The 10-mile population and estimated vehicle ownership are higher near PXSS than
SPAZ.
PXSS experiences a higher traffic volume compared to SPAZ, based on locations
along 1-17 (between exits 195B and 196 for PXSS and between exits 202 and 203 for
SPAZ). The traffic volume near PXSS is the fifth highest compared to traffic volumes
near other NMP sites, with the traffic volume near SPAZ ranking tenth.
The daily VMT for Maricopa County is the second highest compared to other
counties with NMP sites (where VMT data were available).
5.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Arizona on sample days, as well as over the course of the year.
5.2.1 Climate Summary
The Phoenix area is located in the Salt River Valley, which is part of the Sonora Desert.
The area experiences mild winters and extremely hot and dry summers. Differences between the
daytime maximum temperature and overnight minimum temperature can be as high as 50ฐF. A
summer "monsoon" period brings precipitation to the area for part of the summer, while storms
5-7
-------
originating off the Pacific Ocean bring rain in the winter and early spring. Winds are generally
light (Bair, 1992, and WRCC, 2013).
5.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest these sites were
retrieved for 2011 (NCDC, 2011). The closest weather station to PXSS and SPAZ is located at
Phoenix Sky Harbor International Airport (WBAN 23183). Additional information about the Sky
Harbor weather station, such as the distance between the sites and the weather station, is
provided in Table 5-3. These data were used to determine how meteorological conditions on
sample days vary from conditions experienced throughout the year.
Table 5-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 5-3 is the
95 percent confidence interval for each parameter. As shown in Table 5-3, average
meteorological conditions on sample days were representative of average weather conditions
throughout the year. The greatest difference between the full-year averages and sample day
averages is for the maximum and average temperatures for PXSS. This may be due to make-up
samples; thirteen of the nineteen make-up samples were collected between May and October
2011, during the warmer months of the year. Table 5-3 also shows that these sites experienced
the lowest relative humidity levels among NMP sites.
-------
Table 5-3. Average Meteorological Conditions near the Arizona Monitoring Sites
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
Average
Temperature
Average
Dew Point
Temperature
Average
Wet Bulb
Temperature
Average
Relative
Humidity
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Phoenix, Arizona - PXSS
Phoenix Sky
Harbor Intl.
Airport
23183
(33.44, -111.99)
7.19
miles
136ฐ
(SE)
Sample
Day
2011
87.5
ฑ4.0
86.2
ฑ1.7
76.6
ฑ3.8
75.3
ฑ 1.7
35.6
ฑ3.1
34.8
ฑ1.5
55.5
ฑ2.3
54.7
ฑ1.0
28.6
ฑ3.7
28.8
ฑ1.6
1010.8
ฑ1.2
1011.3
ฑ0.6
5.5
ฑ0.5
5.3
ฑ0.2
South Phoenix, Arizona - SPAZ
Phoenix Sky
Harbor Intl.
Airport
23183
(33.44, -111.99)
5.46
miles
70ฐ
(ENE)
Sample
Day
2011
86.2
ฑ6.0
86.2
ฑ1.7
75.2
ฑ5.8
75.3
ฑ1.7
35.1
ฑ4.7
34.8
ฑ 1.5
54.8
ฑ3.4
54.7
ฑ1.0
30.0
ฑ6.1
28.8
ฑ 1.6
1011.4
ฑ1.9
1011.3
ฑ0.6
5.6
ฑ0.7
5.3
ฑ0.2
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
5.2.3 Back Trajectory Analysis
Figure 5-4 is the composite back trajectory map for days on which samples were
collected at the PXSS monitoring site in 2011. Included in Figure 5-4 are four back trajectories
per sample day. Figure 5-5 is the corresponding cluster analysis. Similarly, Figures 5-6 and 5-7
are the composite back trajectory map and corresponding cluster analysis for days on which
samples were collected at SPAZ. An in-depth description of these maps and how they were
generated is presented in Section 3.5.2.1. For the composite maps, each line represents the
24-hour trajectory along which a parcel of air traveled toward the monitoring site on a given
sample day and time, based on an initial height of 50 meters AGL. For the cluster analyses, each
line corresponds to a trajectory representative of a given cluster of back trajectories. Each
concentric circle around the sites in Figures 5-4 through 5-7 represents 100 miles.
Observations from Figures 5-4 and 5-5 for PXSS include the following:
The 24-hour air shed domain for PXSS is the smallest in size, based on average back
trajectory length, compared to other NMP sites. The farthest away a back trajectory
originated from PXSS was over northern Utah, or just greater than 500 miles away.
However, most trajectories (89 percent) originated less than 300 miles from PXSS
and the average trajectory length was approximately 166 miles.
Back trajectories originated from a variety of directions at PXSS, although many
trajectories originated from the southwest and west. A secondary group of trajectories
originated from the north to northeast of the site. Back trajectories also originated
from the east of the site.
The cluster analysis map supports the observations above regarding the direction of
trajectory origin as well as the observations about trajectory distances. Nearly half
(43 percent) of back trajectories originated to the southwest and west of PXSS, over
southwest Arizona, southern California, and Baja California, Mexico. The short
cluster trajectory (40 percent) represents back trajectories originating from nearly all
directions, but generally less than 200 miles in length.
Observations from Figures 5-6 and 5-7 for SPAZ include the following:
Samples were collected every 12 days at SPAZ, which is half the frequency of sample
collection at PXSS. As a result, fewer trajectories are shown in Figure 5-6 than
Figure 5-4.
The composite trajectory map for SPAZ has a trajectory distribution pattern similar to
PXSS. The cluster analysis maps are also similar to each other. One difference,
however, is that for SPAZ, the shorter trajectories of varying directions are included
with the back trajectories originating from the north and east (as represented by the 42
percent cluster), while they are represented by a separate cluster trajectory for PXSS.
5-10
-------
Figure 5-4. 2011 Composite Back Trajectory Map for PXSS
Figure 5-5. Back Trajectory Cluster Map for PXSS
\ \ป \
5-11
-------
Figure 5-6. 2011 Composite Back Trajectory Map for SPAZ
Figure 5-7. Back Trajectory Cluster Map for SPAZ
5-12
-------
5.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Phoenix Sky Harbor
International Airport were uploaded into a wind rose software program to produce customized
wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions
using "petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 5-8 presents a map showing the distance between the NWS station and PXSS,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 5-8 also presents three different wind roses for the
PXSS monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind observations for days on which samples were collected in
2011 is presented. These can be used to identify the predominant wind speed and direction for
2011 and determine if wind observations on sample days were representative of conditions
experienced over the entire year and historically. Figure 5-9 presents the distance map and three
wind roses for SPAZ.
5-13
-------
Figure 5-8. Wind Roses for the Phoenix Sky Harbor International Airport Weather Station
near PXSS
Distance between PXSS and NWS Station
2001-2010 Historical Wind Rose
WIND SPEED
(Knots)
o *=
^| 17 21
^| 11 - 17
^| 7- 11
CH 4-7
! 2- 4
Calms: 15.34%
2011 Wind Rose
Sample Day Wind Rose
5-14
-------
Figure 5-9. Wind Roses for the Phoenix Sky Harbor International Airport Weather Station
near SPAZ
Distance between SPAZ and NWS Station
2001-2010 Historical Wind Rose
: ! V
2011 Wind Rose
Sample Day Wind Rose
Calms: 13.92%
WIND SPEED
(Knots)
n ~*
^| 17 21
JH 11 - 17
^| 7- 11
n 4^7
! 2- 4
Calms; 18.56^
5-15
-------
Observations from Figures 5-8 and 5-9 for the Arizona monitoring sites include the
following:
The NWS weather station at Phoenix Sky Harbor International Airport is the closest
weather station to both PXSS and SPAZ. The Phoenix Sky Harbor weather station is
located approximately 7.2 miles southeast of PXSS and 5.5 miles east-northeast of
SPAZ.
Because the Phoenix Sky Harbor weather station is the closest weather station to both
sites, the historical and 2011 wind roses for PXSS are the same as those for SPAZ.
The historical wind rose shows that easterly winds were the most commonly observed
winds near PXSS and SPAZ (accounting for 20 percent of observations), followed by
westerly and east-southeasterly winds. Winds from the northwest, north, and
northeast were infrequently observed, as were winds from the south. Calm winds
(< 2 knots) account for 15 percent of the hourly wind measurements from 2001 to
2010.
The 2011 wind patterns are similar to the historical wind patterns, with just slightly
more calm wind observations (nearly 19 percent). Further, the sample day wind
patterns for each site resemble the historical and 2011 wind patterns, indicating that
wind conditions on sample days were representative of those experienced over the
entire year and historically.
5.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Arizona monitoring sites in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
For each site, each pollutant's preprocessed daily measurement was compared to its associated
risk screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by each monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 5-4 presents the results of the preliminary risk-based screening process for PXSS
and SPAZ. The pollutants that failed at least one screen and contributed to 95 percent of the total
failed screens for each monitoring site are shaded. NATTS MQO Core Analytes are bolded.
5-16
-------
Thus, pollutants of interest are shaded and/or bolded. PXSS sampled for VOCs, carbonyl
compounds, PAHs, metals (PMio), and hexavalent chromium; SPAZ sampled for VOCs only.
Table 5-4. Risk-Based Screening Results for the Arizona Monitoring Sites
Pollutant
Screening
Value
(Hg/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Phoenix, Arizona - PXSS
Benzene
Carbon Tetrachloride
1,3-Butadiene
Manganese (PM10)
Arsenic (PM10)
Naphthalene
Acetaldehyde
ฃ>-Dichlorobenzene
Formaldehyde
Ethylbenzene
Hexavalent Chromium
1 ,2-Dichloroethane
Nickel (PM10)
Acrylonitrile
Hexachloro- 1 ,3 -butadiene
1 , 1 ,2,2-Tetrachloroethane
Chloromethylbenzene
Benzo(a)pyrene
Cadmium (PM10)
1 ,2-Dibromoethane
Dichloromethane
Propionaldehyde
Tetrachloroethylene
0.13
0.17
0.03
0.005
0.00023
0.029
0.45
0.091
0.077
0.4
0.000083
0.038
0.0021
0.015
0.045
0.017
0.02
0.00057
0.00056
0.0017
7.7
0.8
3.8
Total
61
61
56
55
53
50
48
48
48
44
14
12
12
11
5
3
2
1
1
1
1
1
1
589
61
61
56
61
61
57
48
55
48
61
62
12
61
11
6
o
J
2
30
61
1
61
48
56
983
100.00
100.00
100.00
90.16
86.89
87.72
100.00
87.27
100.00
72.13
22.58
100.00
19.67
100.00
83.33
100.00
100.00
3.33
1.64
100.00
1.64
2.08
1.79
59.92
10.36
10.36
9.51
9.34
9.00
8.49
8.15
8.15
8.15
7.47
2.38
2.04
2.04
1.87
0.85
0.51
0.34
0.17
0.17
0.17
0.17
0.17
0.17
10.36
20.71
30.22
39.56
48.56
57.05
65.20
73.34
81.49
88.96
91.34
93.38
95.42
97.28
98.13
98.64
98.98
99.15
99.32
99.49
99.66
99.83
100.00
South Phoenix, Arizona - SPAZ
Benzene
1,3-Butadiene
Carbon Tetrachloride
ฃ>-Dichlorobenzene
Ethylbenzene
1,2-Dichloroethane
Trichloroethylene
Xylenes
Acrylonitrile
Hexachloro- 1 ,3 -butadiene
0.13
0.03
0.17
0.091
0.4
0.038
0.2
10
0.015
0.045
Total
31
30
30
24
24
7
3
3
1
1
154
31
30
30
29
31
7
12
31
1
1
203
100.00
100.00
100.00
82.76
77.42
100.00
25.00
9.68
100.00
100.00
75.86
20.13
19.48
19.48
15.58
15.58
4.55
1.95
1.95
0.65
0.65
20.13
39.61
59.09
74.68
90.26
94.81
96.75
98.70
99.35
100.00
5-17
-------
Observations from Table 5-4 include the following:
The number of pollutants failing screens varied significantly between the two
monitoring sites; this is expected given the different pollutants measured at each site.
Twenty-three pollutants failed at least one screen for PXSS, of which 13 are NATTS
MQO Core Analytes.
Thirteen pollutants, of which 10 are NATTS MQO Core Analytes, were initially
identified as pollutants of interest for PXSS. Benzo(a)pyrene, cadmium, and
tetrachloroethylene were added to the pollutants of interest for PXSS because they are
NATTS MQO Core Analytes, even though they did not contribute to 95 percent of
the total failed screens. Five additional NATTS MQO Core Analytes were added to
the pollutants of interest for PXSS, even though their concentrations did not fail any
screens: beryllium, chloroform, lead, trichloroethylene, and vinyl chloride. These five
pollutants are not shown in Table 5-4 but are shown in subsequent tables in the
sections that follow.
For PXSS, approximately 60 percent of the measured detections failed screens (of
those pollutants failing at least one screen).
PXSS failed the second highest number of screens (589) among all NMP sites, behind
only S4MO with 602 failed screens (refer to Table 4-8 of Section 4.2). However, the
failure rate for PXSS, when incorporating all pollutants with screening values, is
relatively low, at 23 percent. This is due primarily to the relatively high number of
pollutants sampled at this site, as discussed in Section 4.2.
Ten pollutants failed screens for SPAZ, of which four are NATTS MQO Core
Analytes. Eight pollutants were initially identified as pollutants of interest for SPAZ.
Chloroform and tetrachloroethylene were added to the pollutants of interest for SPAZ
because they are NATTS MQO Core Analytes, even though their concentrations did
not fail any screens. These two pollutants are not shown in Table 5-4 but are shown in
subsequent tables in the sections that follow. While vinyl chloride is also a NATTS
MQO Core Analyte, it was not detected at SPAZ, and therefore not added to the list
of pollutants of interest.
For SPAZ, nearly 76 percent of the measured detections failed screens (of the
pollutants failing at least one screen).
Of the VOCs, which were measured by Method TO-15 at both sites, the following
pollutants of interest failed 100 percent of screens for both sites: acrylonitrile,
benzene, 1,3-butadiene, carbon tetrachloride, and 1,2-dichloroethane.
Hexachloro-1,3-butadiene also failed 100 percent of screens for SPAZ. Acetaldehyde,
chloromethylbenzene, 1,2-dibromoethane, formaldehyde, and
1,1,2,2-tetrachloroethane failed 100 percent of screens at PXSS. However, many of
these pollutants were detected infrequently.
5-18
-------
5.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Arizona monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Arizona monitoring sites, where the data meet the applicable
criteria. Concentration averages for select pollutants are also presented graphically for the sites to
illustrate how the sites' concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the sites. Additional site-
specific statistical summaries for PXSS and SPAZ are provided in Appendices J, L, M, N, and O.
5.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Arizona site, as described in Section 3.1. The quarterly average of a particular pollutant
is simply the average concentration of the preprocessed daily measurements over a given
calendar quarter. Quarterly average concentrations include the substitution of zeros for all non-
detects. A site must have a minimum of 75 percent valid samples of the total number of samples
possible within a given quarter for a quarterly average to be calculated. An annual average
includes all measured detections and substituted zeros for non-detects for the entire year of
sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Arizona
monitoring sites are presented in Table 5-5, where applicable. Note that concentrations of the
PAHs, metals, and hexavalent chromium for PXSS are presented in ng/m3 for ease of viewing.
Also note that if a pollutant was not detected in a given calendar quarter, the quarterly average
simply reflects "0" because only zeros substituted for non-detects were factored into the
quarterly average concentration.
5-19
-------
Table 5-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Arizona Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Hg/m3)
2nd
Quarter
Average
(Hg/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Hg/m3)
Phoenix, Arizona - PXSS
Acetaldehyde
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (PM10)a
Benzo(a)pyrene a
Cadmium (PM10) a
Bery Ilium (PM10)a
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
48/48
61/61
56/61
61/61
57/61
55/61
12/61
61/61
48/48
56/61
16/61
5/61
61/61
30/57
61/61
61/61
62/62
61/61
61/61
57/57
61/61
NA
1.70
ฑ0.38
0.32
ฑ0.10
0.58
ฑ0.02
0.28
ฑ0.06
0.27
ฑ0.06
0.01
ฑ0.02
0.90
ฑ0.23
NA
0.41
ฑ0.10
0.04
ฑ0.02
O.01
ฑ<0.01
0.68
ฑ0.33
0.16
ฑ0.09
0.15
ฑ0.07
0.02
ฑ0.01
0.08
ฑ0.02
4.02
ฑ1.30
11.21
ฑ2.96
107.68
ฑ 27.68
0.92
ฑ0.19
2.26
ฑ0.60
0.73
ฑ0.16
0.08
ฑ0.03
0.55
ฑ0.07
0.31
ฑ0.16
0.10
ฑ0.04
0.05
ฑ0.04
0.51
ฑ0.17
3.58
ฑ0.73
0.83
ฑ1.35
0.02
ฑ0.02
O.01
ฑ<0.01
0.46
ฑ0.21
O.01
ฑ0.01
0.08
ฑ0.02
0.03
ฑ0.01
0.07
ฑ0.03
2.92
ฑ1.14
14.89
ฑ3.21
61.28
ฑ38.49
1.42
ฑ0.29
2.66
ฑ0.53
0.83
ฑ0.20
0.09
ฑ0.04
0.66
ฑ0.05
0.43
ฑ0.17
0.13
ฑ0.05
0
0.59
ฑ0.13
4.29
ฑ0.41
0.21
ฑ0.07
0.01
ฑ0.01
O.01
ฑ<0.01
0.95
ฑ0.37
O.01
ฑ0.01
0.15
ฑ0.07
0.11
ฑ0.05
0.05
ฑ0.02
4.09
ฑ1.00
48.14
ฑ21.67
50.61
ฑ 16.97
2.59
ฑ0.84
3.52
ฑ0.80
1.98
ฑ0.49
0.39
ฑ0.13
0.72
ฑ0.05
0.43
ฑ0.13
0.28
ฑ0.08
0.03
ฑ0.02
1.20
ฑ0.29
4.41
ฑ0.77
0.78
ฑ0.26
0.02
ฑ0.02
0
1.00
ฑ0.30
0.21
ฑ0.10
0.18
ฑ0.06
0.03
ฑ0.01
0.06
ฑ0.02
5.19
ฑ1.64
15.37
ฑ4.79
125.83
ฑ29.09
1.97
ฑ0.75
NA
1.34
ฑ0.22
0.23
ฑ0.06
0.63
ฑ0.03
0.37
ฑ0.07
0.20
ฑ0.04
0.02
ฑ0.01
0.82
ฑ0.13
NA
0.55
ฑ0.28
0.02
ฑ0.01
O.01
ฑO.01
0.77
ฑ0.16
0.10
ฑ0.04
0.14
ฑ0.03
0.05
ฑ0.02
0.06
ฑ0.01
4.06
ฑ0.64
22.82
ฑ6.79
89.36
ฑ 16.23
1.74
ฑ0.33
NA = Not available due to the criteria for calculating a quarterly and/or annual average
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of viewing.
5-20
-------
Table 5-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Arizona Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Hg/m3)
2nd
Quarter
Average
(Hg/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Hg/m3)
South Phoenix, Arizona - SPAZ
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
ฃ>-Dichlorobenzene
Tetrachloroethylene
Trichloroethylene
Xylenes
31/31
30/31
30/31
26/31
7/31
31/31
29/31
28/31
12/31
31/31
2.33
ฑ1.26
0.46
ฑ0.32
0.64
ฑ0.14
0.22
ฑ0.06
0.01
ฑ0.03
1.22
ฑ0.69
0.37
ฑ0.16
0.37
ฑ0.16
0.11
ฑ0.08
4.76
ฑ2.72
0.76
ฑ0.30
0.12
ฑ0.06
0.49
ฑ0.24
0.18
ฑ0.06
0.03
ฑ0.04
0.51
ฑ0.23
0.12
ฑ0.07
0.16
ฑ0.06
0.05
ฑ0.08
1.86
ฑ0.89
0.84
ฑ0.29
0.10
ฑ0.05
0.64
ฑ0.09
0.17
ฑ0.13
0.01
ฑ0.02
0.66
ฑ0.23
0.23
ฑ0.18
0.09
ฑ0.07
0.01
ฑ0.02
2.33
ฑ0.94
2.36
ฑ0.68
0.41
ฑ0.13
0.71
ฑ0.10
0.16
ฑ0.08
0.04
ฑ0.04
1.65
ฑ0.57
0.03
ฑ0.09
0.89
ฑ0.38
0.03
ฑ0.04
6.45
ฑ2.38
1.65
ฑ0.45
0.29
ฑ0.10
0.63
ฑ0.07
0.18
ฑ0.04
0.02
ฑ0.01
1.06
ฑ0.28
0.26
ฑ0.07
0.41
ฑ0.16
0.05
ฑ0.03
4.06
ฑ1.14
NA = Not available due to the criteria for calculating a quarterly and/or annual average
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of viewing.
Observations for PXSS from Table 5-5 include the following:
The pollutant with the highest annual average concentration by mass is benzene. This
is the only pollutant with an annual average concentration greater than 1 |ig/m3
(1.34 ฑ 0.22 |ig/m3). The quarterly average concentrations of benzene exhibit a
seasonal trend, with higher quarterly averages for the colder months of the year.
Similarly, concentrations of benzo(a)pyrene, 1,3-butadiene, and/>-dichlorobenzene
are also higher during the colder months of the year. Ethylbenzene and naphthalene
also appear to exhibit this trend, but the difference in the quarterly average
concentrations is not statistically significant for these pollutants.
The confidence interval for the second quarter average concentration of
tetrachloroethylene is higher than the average itself, indicating the likely influence of
outliers. The highest concentration of this pollutant was measured at PXSS on
May 9, 2011 (8.63 |ig/m3) and is nearly five times greater than the next highest
concentration of this pollutant measured at PXSS (1.74 |ig/m3) and more than three
times the next highest concentration measured among NMP sites sampling VOCs
(2.42 |ig/m3, measured at NBIL).
5-21
-------
The third quarter average concentration of manganese is three times higher than the
other quarterly averages and has a relatively large confidence interval associated with
it. Three of the five concentrations of manganese greater than 100 ng/m3 measured
across the program were measured at PXSS. All three of these measurements were
measured during the third quarter of 2011, one in each month and ranged from
111 ng/m3to 130 ng/m3.
Regarding hexavalent chromium measurements at PXSS: stainless steel filter holders
used in the hexavalent chromium sampler at PXSS may have contaminated the
samples collected at this site. The filter holder was exchanged with a Teflonฎ filter
holder at the end of February 2011. Although the first quarter average is the highest
quarterly average for 2011, the difference is not statistically significant and the
maximum concentration of hexavalent chromium was not measured during the first
quarter. Of the nine concentrations greater than 0.1 ng/m3, four were measured during
the first quarter, two in the second, one in the third, and two in the fourth.
Note that neither acetaldehyde nor formaldehyde have first quarter or annual average
concentrations presented in Table 5-5. This is because maintenance of the primary
carbonyl compound sampler at PXSS led to a problem with the ozone denuder,
resulting in the invalidation of the sampling results through the end of March 2011.
However, Appendix L provides the pollutant-specific average concentrations for all
valid samples collected over the entire sample period for each site.
Observations for SPAZ from Table 5-5 include the following:
The pollutant with the highest annual average concentration by mass for SPAZ is
xylenes (4.06 ฑ 1.14 |ig/m3), which is more than twice the next highest annual
average for benzene (1.65 ฑ 0.45 |ig/m3). Ethylbenzene is the only other pollutant of
interest with an annual average greater than 1 |ig/m3 (1.06 ฑ 0.28 |ig/m3).
The first and fourth quarterly averages of xylene are more than twice the quarterly
averages for the second and third quarters and have relatively large confidence
intervals associated with them. Xylenes were detected in all 31 valid VOC samples
collected at SPAZ and ranged from 0.879 |ig/m3to 11.93 |ig/m3. Of these 31, the
eight highest concentrations (those greater than 5 |ig/m3) were all measured in the
first and fourth quarters; conversely, the four lowest concentrations (those less than
1 |ig/m3) were measured during the second and third quarters. SPAZ is the only site
for which xylenes is a pollutant of interest.
Similar to PXSS, the quarterly average concentrations of several of the VOCs exhibit
a seasonal trend, with the averages being higher during the colder months of year.
However, the confidence intervals indicate that the differences in the quarterly
averages are not statistically significant for SPAZ.
5-22
-------
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for PXSS and
SPAZ from those tables include the following:
PXSS and SPAZ appear in Tables 4-9 through 4-12 a total of 25 times.
SPAZ has the highest annual average concentration of 1,3-butadiene,
/>-dichlorobenzene, and ethylbenzene among all NMP sites sampling VOCs, and the
second highest annual averages of benzene and tetrachloroethylene. PXSS has the
highest annual average concentration of tetrachloroethylene and the second highest
annual average concentrations of 1,3-butadiene and ethylbenzene among sites
sampling VOCs.
PXSS has the highest annual average concentration of hexavalent chromium among
all NMP sites sampling this pollutant. However, the annual average for 2011 is half of
what it was in 2010 (0.13 ฑ 0.03 ng/m3).
PXSS also has the highest annual average concentrations of beryllium and
manganese, the second highest annual averages of arsenic and nickel, and the third
highest annual average concentration of lead, among NMP sites sampling PMi0
metals.
5.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzene and 1,3-butadiene
were created for both PXSS and SPAZ. Box plots were also created for arsenic, benzo(a)pyrene,
hexavalent chromium, lead, manganese, and naphthalene for PXSS. Figures 5-10 through 5-17
overlay the sites' minimum, annual average, and maximum concentrations onto the program-
level minimum, first quartile, median, average, third quartile, and maximum concentrations, as
described in Section 3.5.3.
5-23
-------
Figure 5-10. Program vs. Site-Specific Average Arsenic (PMi0) Concentration
2 2.5
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
Figure 5-11. Program vs. Site-Specific Average Benzene Concentrations
SFiZ
i Program Max Concentration = 23. 8 UR/m3
1
'
|
:
j
4 5
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 5-12. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
Concentration (ng/mi)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
5-24
-------
Figure 5-13. Program vs. Site-Specific Average 1,3-Butadiene Concentrations
j
i Program Max Concentration = 9.51 |ag/m3
-o-
Program Max Concentration = 9.51 ug/m3
1.5
Concentration (
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 5-14. Program vs. Site-Specific Average Hexavalent Chromium Concentration
0.05
0.1
0.15
Concentration (ng/m3)
3.2
0.25
D.3
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 5-15. Program vs. Site-Specific Average Lead (PMi0) Concentration
15 20
Concentration (ng/m3)
Program:
Site:
IstQuartile
Site Average
0
2ndQuartile
SrdQuartile
n
4thQuartile Average
n
^B 1 1
Site Minimum/Maximum
5-25
-------
Figure 5-16. Program vs. Site-Specific Average Manganese (PMi0) Concentration
1
,: Program Max Concentration =
395 ng/m3
75 100 125
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 5-17. Program vs. Site-Specific Average Naphthalene Concentration
,
1
*^L r
Program Max Concentration -779 ng/m
, !
i
::: 250 3:0
Concentration (nฃ/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 5-10 through 5-17 include the following:
Figure 5-10 shows that the annual average arsenic (PMio) concentration for PXSS
is greater than the program-level average for arsenic (PMio). Although the
maximum concentration of arsenic measured across the program was not
measured at PXSS, the maximum concentration measured at PXSS (3.05 ng/m3)
was among the higher arsenic measurements. There were no non-detects of
arsenic measured at PXSS.
Figure 5-11 for benzene shows both sites, as both SPAZ and PXSS sampled
VOCs. Note that the program-level maximum concentration (23.8 |ig/m3) is not
shown directly on the box plots because the scale of the box plots would be too
large to readily observe data points at the lower end of the concentration range.
Thus, the scale of the box plots has been reduced to 10 |ig/m3. While neither
Arizona site measured the maximum benzene concentration measured across the
program, both annual averages are greater than the program-level average
concentration. The annual average benzene concentration for SPAZ is slightly
higher than the annual average concentration for PXSS. SPAZ has the second
highest annual average concentration of benzene among NMP sites sampling this
pollutant, as discussed above. There were no non-detects of benzene measured at
either site (or among sites sampling VOCs).
5-26
-------
Figure 5-12 is the box plot for benzo(a)pyrene for PXSS. Note that the program-
level first quartile for this pollutant is zero and is not visible on this box plot. The
box plot shows that the annual average concentration for PXSS is just greater than
the program-level average concentration and just less than the program-level third
quartile. Figure 5-12 also shows that the maximum concentration measured at
PXSS is considerably less than the maximum concentration measured across the
program. Several non-detects of benzo(a)pyrene were measured at PXSS.
Figure 5-13 for 1,3-butadiene also shows both sites. Similar to the box plots for
benzene, the program-level maximum 1,3-butadiene concentration (9.51 |ig/m3) is
not shown directly on the box plots as the scale has been reduced to 3 |ig/m3 in
order to allow for the observation of data points at the lower end of the
concentration range. The annual average concentrations for both sites are more
than twice the program-level average concentration. Further, these two sites have
the highest annual average concentrations of this pollutant across the program, as
mentioned above, with the 1,3-butadiene annual average concentration for SPAZ
slightly higher than the annual average concentration for PXSS. There were five
non-detects of 1,3-butadiene measured at PXSS and one non-detect measured at
SPAZ.
Figure 5-14 is the box plot for hexavalent chromium for PXSS. Figure 5-14 shows
that the maximum concentration of this pollutant across the program
(0.268 ng/m3) was measured at PXSS. The box plot also shows that this site's
annual average concentration of hexavalent chromium (0.065 ng/m3) is nearly
three times greater than the program-level average concentration (0.024 ng/m3).
As discussed above, PXSS has the highest annual average concentration of
hexavalent chromium among NMP sites sampling hexavalent chromium. There
were no non-detects of hexavalent chromium measured at PXSS.
Figure 5-15 shows that the annual average concentration of lead (PMio) for PXSS
is just greater than the program-level average concentration. While the maximum
concentration measured at PXSS is considerably less than the program maximum
concentration, PXSS has the third highest annual average concentration of lead
among the NMP sites, behind only S4MO and NBIL. There were no non-detects
of lead measured at PXSS (or among sites sampling PMio metals).
Figure 5-16 is the box plot for manganese (PMio) for PXSS. Note that the
program-level maximum concentration (395 ng/m3) is not shown directly on the
box plot as the scale has been reduced to 200 ng/m3 in order to allow for the
observation of data points at the lower end of the concentration range. Figure 5-16
shows the annual average concentration of manganese for PXSS (22.82 ng/m3) is
greater than the program-level average concentration (8.81 ng/m3), nearly two and
a half times as high). PXSS has the highest annual average concentration of
manganese among NMP sites sampling PMio metals, as discussed above. While
the maximum concentration measured at PXSS (130 ng/m3) is considerably less
than the program-level maximum concentration, this is the second highest
measurement of manganese measured among the NMP sites sampling
5-27
-------
metals. There were no non-detects of manganese measured at PXSS (or among
sites sampling PMi0 metals).
Figure 5-17 is the box plot for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 500 ng/m3 in order to allow for the observation of data
points at the lower end of the concentration range. Figure 5-17 shows that the
annual average naphthalene concentration for PXSS (89.36 ng/m3) is greater than
the program-level average concentration (81.68 ng/m3). The maximum
naphthalene concentration measured at PXSS (293 ng/m3) is considerably less
than the program-level maximum concentration. There were no non-detects of
naphthalene measured at PXSS (or among sites sampling PAHs).
Recall that annual averages could not be calculated for formaldehyde and
acetaldehyde, as discussed in Section 5.4.1.
5.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. PXSS has sampled PMi0 metals and hexavalent chromium under the NMP since
2006; thus, Figures 5-18 through 5-21 present the annual statistical metrics for arsenic,
hexavalent chromium, lead, and manganese, respectively. The statistical metrics presented for
assessing trends include the substitution of zeros for non-detects.
SPAZ began sampling VOCs and PXSS began sampling VOCs, carbonyl compounds,
and PAHs under the NMP in 2007. However, they did not begin sampling until halfway through
the year; therefore, annual statistical metrics could not be calculated for 2007. Thus, the trends
analysis was not conducted for the pollutants for these methods for PXSS and SPAZ.
5-28
-------
Figure 5-18. Annual Statistical Metrics for Arsenic (PMi0) Concentrations Measured at
PXSS
tf\
[ration (ng/r
rage Concen
r
T
1 r ^
L 6
5 1
ซ, ^ ...^
1 f f t ป
2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median - Maximum 95th Percentile ..^.. Average
Figure 5-19. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at PXSS
t rat ion (ng/m3)
S 1
ti I
1
3
1
"c,
"
ซ
'
20
0
t f
._ *
J... | |.-ป-..|... r^
^ ^? Lzl L5 L_jJ El^i
06 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median - Maximum 95th Percentile ...+*. Average
5-29
-------
Figure 5-20. Annual Statistical Metrics for Lead (PMi0) Concentrations Measured at PXSS
2008 2009
Year
5th Percentile Minimum Median - Maximum 95th Percentile
> Average
Figure 5-21. Annual Statistical Metrics for Manganese (PMi0) Concentrations Measured at
PXSS
80
200S 2009
Year
* 5th Percentile Minimum Median - Maximurr
.-*
95th Percentile ..^.. Average
5-30
-------
Observations from Figure 5-18 for arsenic measurements at PXSS include the following:
PXSS began sampling arsenic under the NMP in January 2006.
The maximum arsenic concentration (6.73 ng/m3) was measured on
December 26, 2007 and is more than twice the next highest concentration
(3.05 ng/m3), measured on August 19, 2011.
The average concentration increased from 2010 to 2011 after several years of slight
decreasing, although the changes across the years of sampling are not statistically
significant. The averages range from 0.51 ng/m3 in 2010 to 0.77 ng/m3 in 2011.
Observations from Figure 5-19 for hexavalent chromium measurements at PXSS include
the following:
PXSS began sampling hexavalent chromium in January 2006.
The maximum hexavalent chromium concentration shown was measured on
July 10, 2006 (0.989 ng/m3). The second highest concentration was also measured in
2006 (0.737 ng/m3).
There is little statistical difference in the average concentrations, which range from
0.06 ng/m3 in 2011 to 0.13 ng/m3 in 2006 and 2010.
For 2011, the difference between the average and the median concentrations is at a
minimum, indicating decreasing variability in the concentrations measured.
Observations from Figure 5-20 for lead measurements at PXSS include the following:
The maximum lead concentration (23.1 ng/m3) was measured on January 1, 2009.
The second highest concentration (17.4 ng/m3) was measured on December 31, 2006.
Similar to arsenic, the average lead concentrations exhibit an increase for 2011 after a
decreasing trend between 2008 and 2010.
There have been no non-detects reported for lead since the onset of lead sampling at
PXSS. The minimum concentrations for 2007 and 2008 are considerably less than the
others, but are still numerical measurements.
Observations from Figure 5-21 for manganese measurements at PXSS include the
following:
Three manganese concentrations greater than 100 ng/m3 have been measured at PXSS
since 2006; all three were measured in 2011. Of the nine concentrations greater than
50 ng/m3, five were measured during 2011.
5-31
-------
The annual average concentration of manganese for 2011 is twice the average for
2010 and represents a significant increase between the two years. Over the course of
sampling, the measurements from 2011 exhibit the highest variability while the
measurements from 2010 exhibit the least. Regardless, this site still has some of the
highest levels of manganese among sites sampling PMi0 metals; PXSS had the second
highest annual average concentration of manganese for 2010 and the highest annual
average across the program for 2011.
The 95th percentile for 2011 is significantly higher than for the previous years of
sampling, indicating that a greater number of concentrations were on the higher side
for 2011.
The widening difference between the median and the annual average concentration
for 2011 is a further indication of the increasing variability of the 2011 manganese
measurements, whereas for 2010, the median and average concentrations were less
than 0.30 ng/m3 apart.
5.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each Arizona monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
5.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Arizona monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
5-32
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5.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Arizona monitoring sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 5-6, where applicable. Cancer risk approximations
are presented as probabilities while the noncancer hazard approximations are ratios and thus,
unitless values.
Observations for PXSS from Table 5-6 include the following:
The pollutants with the highest annual average concentrations by mass are benzene,
ethylbenzene, and carbon tetrachloride, with only benzene having an annual average
concentration greater than 1 |ig/m3.
Based on the annual averages and cancer UREs, benzene, 1,3-butadiene, and carbon
tetrachloride have the three highest cancer risk approximations. An additional four
pollutants have cancer risk approximations greater than 1.0 in-a-million.
None of the pollutants of interest for PXSS have noncancer hazard approximations
greater than 1.0, indicating that no adverse health effects are expected from these
individual pollutants. The pollutant with the highest noncancer hazard approximation
for PXSS is manganese (0.46).
The noncancer hazard approximation for PXSS for manganese is the third highest
noncancer hazard approximation calculated across the program and the second
highest for this pollutant (second only to TOOK).
Annual averages (and therefore cancer risk and noncancer hazard approximations)
could not be calculated for acetaldehyde and formaldehyde, as discussed in
Section 5.4.1.
5-33
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Table 5-6. Risk Approximations for the Arizona Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Phoenix, Arizona - PXSS
Acetaldehyde
Arsenic (PM10)a
Benzene
Benzo(a)pyrene a
Bery Ilium (PM10)a
1,3 -Butadiene
Cadmium (PM10)a
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Hexavalent Chromium a
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.0043
0.0000078
0.00176
0.0024
0.00003
0.0018
0.000006
0.000011
0.000026
0.0000025
0.000013
0.012
0.000034
0.00048
0.00000026
0.0000048
0.0000088
0.009
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
0.8
2.4
1
0.0098
0.0001
0.00015
0.00005
0.003
0.00009
0.04
0.002
0.1
48/48
61/61
61/61
30/57
61/61
56/61
61/61
61/61
57/61
55/61
12/61
61/61
48/48
62/62
61/61
61/61
57/57
61/61
56/61
16/61
5/61
NA
0.01
ฑ0.01
1.34
ฑ0.22
0.01
ฑ0.01
0.01
ฑ0.01
0.23
ฑ0.06
0.01
ฑ0.01
0.63
ฑ0.03
0.37
ฑ0.07
0.20
ฑ0.04
0.02
ฑ0.01
0.82
ฑ0.13
NA
O.01
ฑO.01
0.01
ฑ 0.01
0.02
ฑ0.01
0.09
ฑ0.02
O.01
ฑO.01
0.55
ฑ0.28
0.02
ฑ0.01
0.01
ฑ0.01
NA
3.33
10.48
0.18
0.11
6.89
0.25
3.80
2.19
0.57
2.05
NA
0.78
3.04
0.83
0.14
0.10
0.01
NA
0.05
0.04
0.01
0.11
0.01
0.01
0.01
O.01
0.01
O.01
NA
O.01
0.03
0.46
0.03
0.02
0.01
0.01
0.01
= a Cancer URE or Noncancer RfC is not available.
NA = Not available due to the criteria for calculating an annual average.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 5-5.
5-34
-------
Table 5-6. Risk Approximations for the Arizona Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
South Phoenix, Arizona - SPAZ
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
ฃ>-Dichlorobenzene
Tetrachloroethylene
Trichloroethylene
Xylenes
0.0000078
0.00003
0.000006
0.000026
0.0000025
0.000011
0.00000026
0.0000048
0.03
0.002
0.1
0.098
2.4
1
0.8
0.04
0.002
0.1
31/31
30/31
30/31
26/31
7/31
31/31
29/31
28/31
12/31
31/31
1.65
ฑ0.45
0.29
ฑ0.10
0.63
ฑ0.07
0.18
ฑ0.04
0.02
ฑ0.01
1.06
ฑ0.28
0.26
ฑ0.07
0.41
ฑ0.16
0.05
ฑ0.03
4.06
ฑ1.14
12.88
8.66
3.79
0.56
2.66
2.91
0.11
0.24
0.06
0.14
0.01
0.01
<0.01
0.01
0.01
0.01
0.02
0.04
= a Cancer URE or Noncancer RfC is not available.
NA = Not available due to the criteria for calculating an annual average.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 5-5.
Observations for SPAZ from Table 5-6 include the following:
The pollutants with the highest annual average concentrations by mass are xylenes,
benzene, and ethylbenzene. These three pollutants are the only ones with an annual
average concentration greater than 1 |ig/m3.
Based on the annual averages and cancer UREs, benzene, 1,3-butadiene, and carbon
tetrachloride have the three highest cancer risk approximations. Two additional
pollutants have cancer risk approximations greater than 1.0 in-a-million.
The cancer risk approximation for SPAZ for benzene (12.88 in-a-million) is the
second highest cancer risk approximation calculated for this pollutant across the
program (second only to TOOK). The cancer risk approximation for PXSS for
benzene (10.48 in-a-million) ranks fifth.
None of the pollutants of interest for SPAZ have noncancer hazard approximations
greater than 1.0, indicating no adverse health effects are expected from these
individual pollutants. The pollutant with the highest noncancer hazard approximation
for SPAZ is 1,3-butadiene (0.14).
5-35
-------
5.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 5-7 and 5-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 5-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 5-6. Table 5-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 5-6.
The pollutants listed in Table 5-7 and 5-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 5.3, PXSS sampled for VOCs, carbonyl compounds, PAHs, metals (PMio), and
hexavalent chromium; SPAZ sampled for VOCs only. In addition, the cancer risk and noncancer
hazard approximations are limited to those pollutants with enough data to meet the criteria for
annual averages to be calculated; thus, cancer risk and noncancer hazard approximations were
not calculated for formaldehyde and acetaldehyde. A more in-depth discussion of this analysis is
provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this
analysis may help policy-makers prioritize their air monitoring activities.
5-36
-------
Table 5-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer
UREs for the Arizona Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Phoenix, Arizona (Maricopa County) - PXSS
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group la
Propylene oxide
1,256.37
969.28
766.10
487.50
179.20
90.54
28.45
14.68
2.61
1.66
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
Ethylbenzene
Hexavalent Chromium, PM
POM, Group 2b
Acetaldehyde
Arsenic, PM
POM, Group 5a
1.26E-02
9.80E-03
5.38E-03
3.08E-03
1.92E-03
1.70E-03
1.29E-03
1.07E-03
7.14E-04
3.83E-04
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Arsenic
Naphthalene
ฃ>-Dichlorobenzene
Ethylbenzene
Nickel
Hexavalent Chromium
1 ,2-Dichloroethane
10.48
6.89
3.80
3.33
3.04
2.19
2.05
0.83
0.78
0.57
South Phoenix, Arizona (Maricopa County) - SPAZ
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group la
Propylene oxide
1,256.37
969.28
766.10
487.50
179.20
90.54
28.45
14.68
2.61
1.66
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
Ethylbenzene
Hexavalent Chromium, PM
POM, Group 2b
Acetaldehyde
Arsenic, PM
POM, Group 5a
1.26E-02
9.80E-03
5.38E-03
3.08E-03
1.92E-03
1.70E-03
1.29E-03
1.07E-03
7.14E-04
3.83E-04
Benzene
1,3 -Butadiene
Carbon Tetrachloride
ฃ>-Dichlorobenzene
Ethylbenzene
1 ,2-Dichloroethane
Trichloroethylene
Tetrachloroethylene
12.88
8.66
3.79
2.91
2.66
0.56
0.24
0.11
-------
Table 5-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with
Noncancer RfCs for the Arizona Monitoring Sites
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Phoenix, Arizona (Marico]
Toluene
Xylenes
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
Glycol ethers, gas
3,931.16
2,893.73
1,256.37
969.28
963.82
766.10
487.50
240.60
179.20
98.40
Acrolein
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Lead, PM
Benzene
Naphthalene
Xylenes
Arsenic, PM
Propionaldehyde
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
pa County) - PXSS
2,430,403.47
98,905.78
89,599.85
54,166.44
42,964.38
41,879.01
30,178.52
28,937.26
11,077.09
8,611.73
Manganese
1,3 -Butadiene
Arsenic
Benzene
Naphthalene
Lead
Nickel
Cadmium
Tetrachloroethylene
Trichloroethylene
0.46
0.11
0.05
0.04
0.03
0.03
0.02
0.01
0.01
0.01
South Phoenix, Arizona (Maricopa County) - SPAZ
Toluene
Xylenes
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
Glycol ethers, gas
3,931.16
2,893.73
1,256.37
969.28
963.82
766.10
487.50
240.60
179.20
98.40
Acrolein
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Lead, PM
Benzene
Naphthalene
Xylenes
Arsenic, PM
Propionaldehyde
2,430,403.47
98,905.78
89,599.85
54,166.44
42,964.38
41,879.01
30,178.52
28,937.26
11,077.09
8,611.73
1,3 -Butadiene
Benzene
Xylenes
Trichloroethylene
Tetrachloroethylene
Carbon Tetrachloride
Chloroform
Ethylbenzene
ฃ>-Dichlorobenzene
1,2-Dichloroethane
0.14
0.06
0.04
0.02
0.01
0.01
0.01
0.01
0.01
0.01
fj\
-------
Observations from Table 5-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Maricopa County.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
cancer UREs) are formaldehyde, benzene, and 1,3-butadiene.
Seven of the highest emitted pollutants in Maricopa County also have the highest
toxicity-weighted emissions.
Benzene, 1,3-butadiene, and carbon tetrachloride have highest cancer risk
approximations for both PXSS and SPAZ. While benzene and 1,3-butadiene both
appear among the pollutants with the 10 highest emissions and 10 highest toxicity-
weighted emissions for Maricopa County, carbon tetrachloride does not appear on
either list. In addition to benzene and 1,3-butadiene, ethylbenzene also appears on all
three lists for both sites. Naphthalene also appears on all three lists for PXSS.
POM, Group 2b is the eighth highest emitted "pollutant" in Maricopa County and
ranks seventh for toxicity-weighted emissions. POM, Group 2b includes several
PAHs sampled for at PXSS including acenaphthene, benzo(e)pyrene, fluoranthene,
and perylene. None of the PAHs included in POM, Group 2b were identified as
pollutants of interest for PXSS.
POM, Group 5a is the pollutant with the tenth highest toxicity-weighted emissions for
Maricopa County. Benzo(a)pyrene is part of POM, Group 5a.
Observations from Table 5-8 include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs in Maricopa County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, formaldehyde, and 1,3-butadiene.
Five of the highest emitted pollutants also have the highest toxicity-weighted
emissions.
Acrolein has the highest toxicity-weighted emissions (by two orders of magnitude)
for Maricopa County. Although acrolein was sampled for at both sites, this pollutant
was excluded from the pollutants of interest designation, and thus subsequent risk-
based screening evaluations, due to questions about the consistency and reliability of
the measurements, as discussed in Section 3.2.
Manganese has the highest noncancer hazard approximation for PXSS (although
considerably less than an HQ of 1.0), followed by 1,3-butadiene. 1,3-Butadiene has
the highest noncancer hazard approximation for SPAZ. In addition to 1,3-butadiene,
benzene and xylenes all appear on all three lists for both sites.
5-39
-------
Five metals appear among the 10 pollutants with highest noncancer hazard
approximations for PXSS. Two of these (arsenic and lead) are among those with the
highest toxicity-weighted emissions while none appear among the highest emitted
pollutants in Maricopa County.
5.6 Summary of the 2011 Monitoring Data for PXSS and SPAZ
Results from several of the data treatments described in this section include the
following:
ปซป Twenty-three pollutants failed screens for PXSS; 14 of these are NA TTSMQO Core
Analytes. Ten pollutants failed screens for SPAZ, of which four are NATTSMQO
Core Analytes.
*ป* Of the site-specific pollutants of interest for PXSS, benzene had the highest annual
average concentration and was the only pollutant with an annual average greater
than 1 jug/m3. For SPAZ, xylenes had the highest annual average concentration
among this site's pollutants of interest.
ปซป Concentrations of several VOCs, including benzene and 1,3-butadiene, tended to be
slightly higher during the colder months of the year.
ปซป PXSS has the highest annual average concentration oftetrachloroethylene,
hexavalent chromium, beryllium (PMw), and manganese (PMw) among all NMP sites
sampling these pollutants; SPAZ has the highest annual average concentration of
1,3-butadiene, p-dichlorobenzene, and ethylbenzene among all NMP sites sampling
VOCs.
5-40
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6.0 Sites in California
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at three NATTS sites in California, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
6.1 Site Characterization
This section characterizes the California monitoring sites by providing geographical and
physical information about the locations of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
The California monitoring sites are located in Los Angeles, Rubidoux, and San Jose.
Figures 6-1, 6-3, and 6-5 are composite satellite images retrieved from ArcGIS Explorer showing
the monitoring sites in their urban locations. Figures 6-2, 6-4, and 6-6 identify nearby point
source emissions locations by source category, as reported in the 2008 NEI for point sources.
Note that only sources within 10 miles of the sites are included in the facility counts provided in
Figures 6-2, 6-4, and 6-6. A 10-mile boundary was chosen to give the reader an indication of
which emissions sources and emissions source categories could potentially have a direct effect
on the air quality at the monitoring sites. Further, this boundary provides both the proximity of
emissions sources to the monitoring sites as well as the quantity of such sources within a given
distance of the sites. Sources outside each 10-mile radius are still visible on the maps, but have
been grayed out in order to show emissions sources just outside the boundary. Table 6-1 provides
supplemental geographical information such as land use, location setting, and locational
coordinates.
6-1
-------
to
Figure 6-1. Los Angeles, California (CELA) Monitoring Site
__^ " V, .'- ป i ' ?-!_.ซ-
-------
Figure 6-2. NEI Point Sources Located Within 10 Miles of CELA
2
0 ,? + *""
U8"15"0"W 115 10'0~W 118'5H1"W 118'OXTW
Note: Due to facilily density and collocation, the total facilities
displayed may not represent all facilities within the area of interest
Legend
& CELA NATTS site 10 mile radius
County boundary
Source Category Group (No. of Facilities)
Ip Aerospace/Aircraft Manufacturing (2)
0 Air-comJitioning/Refrigeratwn (1)
-f" Aircraft Operations (62)
I Asphgtt Processing/Roofing Manufacturing (2)
<> Auto Body Shop/Pamlers (12)
S Automobile/Tnjck Manufacturing (4)
0 Bakery (4)
X Battery Manufacturing (2)
tf Burning Construction (4)
B Bulk Terminals/Bulk Plants (2)
C Cltemtcal Manufacturing (8)
Concrete Batch Plant (1)
XJ Crematory - Animal/Human (2)
6 Etectncat Equipment (2)
ฃ EteclrMy Generation via Combustion (5)
E Electroplating, Plating. Polishing. Anodizing. & Coloring (17)
ฉ Fabricated Metal Products (11)
fe9 Flexible PolyureUiane Foam Production (2)
F Food Processing/Agriculture (13)
[" ! Furniture Plant {20)
1* Glass Manufacturing (2)
A Grain Handling (2)
(V Heating Equipment Manufacturing (1)
[3 Hospital (4)
$ Hoi MiK Asphalt Plant (1)
T Industrial Machinery and Equipment (5)
Ip Institutional prison (1)
^ Institutional - school (1}
I Iron and Steel Foundry (7}
A Landfill (1)
V Leather and Leather Products (1}
V Mineral Products (1)
? Miscellaneous Commercial Industrial (31)
M Miscellaneous Manufacturing (6)
0 Municipal V^iste Combustor(1 >
Oil artd/or Gas Production (11)
jt Pel roleum Refinery (1)
^- PnarmaceuttcalManufaclunng (1)
1 Primary Metal Production (8)
P Printing/Publishing (26)
IB Pulp and Paper Pian(/VWปd Products (9)
R Rubber and Miscellaneous Plastics Products (6)
2 Secondary Melal Processing (4)
< Site Remediation Activity {1)
V S1eelMill(2)
S Surface Coaling (10)
TT TeleoonvntmBattons (2)
T Textile Mill (8)
*v Transportation Equipmenl (2)
l V^atewater Treatment (6)
W V*odworh, Furniture, Miltoorfc & V\food Preserving (2)
6-3
-------
Figure 6-3. Rubidoux, California (RUCA) Monitoring Site
-------
Figure 6-4. NEI Point Sources Located Within 10 Miles of RUCA
117'30'CTW 117'25'frW 117'20^"W 117"15TJPW
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
Legend
@ RUCA NATTS site 10 mile radius Q ] County boundary
Source Category Group (No. of Facilities)
i$* Ae rospacefAircraft Manufacturing (1)
41 Aircraft Operations (12)
I Asphalt Processing/Roofing Manufacturing (3)
0 Auto Body Shop/Painters (6)
H AutomobileiTruck Manufacturing (7)
$ Bakery (3)
ฑ BoatManufactunngd)
Brick Manufacturing & Structural Clay (2)
ft Building Construction (3)
B Bulk Terminals^Bulk Plants (2)
C Chemical Manufacturing (1)
Concrete Batch Plant (5)
8 Electrical Equipment (5)
f Electricity Generation via Combustion (4)
ฉ Fabricated Metal Products (10)
Flexible Polyurethane Foam Production (1)
Food Processing/Agriculture (18)
Furniture Plant (1)
GasolmeiDiesel Service Station (1)
Hospital (1)
Hot Mix Asphalt Plant(1)
Industrial Machinery and Equipment (2)
Institutional prison (1)
Institutional - school (5)
Landfill (4)
Lumber/sawmill (1)
Mine/Quarry (3)
Mineral Products (2)
Miscellaneous Commercial/Industrial (10)
Miscellaneous Manufacturing (2)
Oil and/or Gas Production (3)
* Other Solid Vvaste Incineration (1)
7 Portland Cement Manufactunng (2)
1 Primary Metal Production (4)
P PrrtngCPublishing(IO)
H Pulp and Paper PlanuWsod Products (4)
R Rubber and Miscellaneous Plastics Products (6)
2 Secondary Metal Processing (2)
< SiteRenwdiafion Activity (1)
> Solid Waste Disposal - Comrnerciairinstitutional (1)
V Steel Mill (4)
S Surface Coaling (4)
** Transportation Equipment (3)
$ฃ Transportation and Marketing of Petroleum Products (1)
Mfeslewater Treatment (9)
W Woodwork, Furniture. Milrwork 4 Wsod Preserving (2)
6-5
-------
Figure 6-5. San Jose, California (SJJCA) Monitoring Site
Oi
-------
Figure 6-6. NEI Point Sources Located Within 10 Miles of SJJCA
Legend
1ZV55'CrW tZrSO'FW 121*4510"W 121 4QXJ-W
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
SJJCA NATTS site Q 10 mile radius
County boundary
Source Category Group (No. of Facilities)
:\h An (2)
HH Aircraft Operations (19)
I Asphalt Processing/Roofing Manufacturing (4)
0 Auto Body Shop/Painters (235)
H Automobile/Truck Manufacturing (17)
fe BaKery(2)
X Battery ManufBdunng (1)
Brick Manufacturing & Structural Clay (3)
ft Budding ConsUuclion (15)
5 Bulk Terminals/Bulk Plants (5)
C Chemical Manufactunr^<5)
O Clay Ceramics Manufacturing (1)
Concrete Batch Plant (10)
XCrematory - Aiwnal/Human (3)
ฎ Dry Cleaning Facdtty (161)
& Electncal Equipment (250)
f Electricity Generation via Combuston (2)
E Etectroplaling, Plalmg, Pobshmg. ArwdJang, SCotonng (14)
4 Ermine Testing (1)
ฉ Fabricated Metal Producls (35)
^ Flexible Potyurethane Foam Produclidn (2)
F Food Process ing'AgricurtuTe (43)
I , Furniture Plant (37)
V Gasoline/Diesel Service Station (9)
^t Glass Manufacturing (1)
A Grain Handling (2)
// Healing Equipment Manufacturing (7)
[3 Hospital (16)
ฃ Hoi Mix Asphalt Plant (1)
^fr Industrial Machinery and E(^iiprnenl (19)
l|r Institutional - school (27)
I Iron and Steel Foundry (1)
^ Laboratory (7)
W Leather and Leather Products {1)
/ Lumber/sawmill (1)
A Mflftary Base/Nalional Secitnty Facility (7)
X Mine/Quarry (5)
4i Mineral Wool Manufacturing (1)
? Miscellaneous Commercial/Industrial (212)
M Miscellaneous Manufacturing (69)
0ซ1 and/or C3as Production (3)
I Pharmaceutical Manufacturing (9)
1 Primary Melal Production (2)
P Printing/Publishing (30)
B Pulp and Paper Plant/Wood Products (W)
R Rubber and Miscellaneous Plastics Products (3)
2 Secondary Melal Processing (3)
< Erie Remedialion Activity (13)
> Solid Waste Disposal - Commercial,'mstitutซ>na] (26)
V Steel Mill (1}
S Surface Coating (32)
IT Tetecommunica1.K)ns{102)
T Textile Mill (5)
ซ* Transportation Equipment (5)
ifc Transportation and Marketing of Petroleum Products (3)
1 Wfcstewater Trea tmenl (IS)
W Woodwork. Furrature. Miflwork & Wood Preserving (2)
6-7
-------
Table 6-1. Geographical Information for the California Monitoring Sites
Site
Code
CELA
RUCA
SJJCA
AQS Code
06-037-1103
06-065-8001
06-085-0005
Location
Los
Angeles
Rubidoux
San Jose
County
Los
Angeles
Riverside
Santa
Clara
Micro- or
Metropolitan
Statistical Area
Los Angeles-Long
Beach-Santa Ana,
CAMSA
Riverside-San
Bernardino-
Ontario, CA MSA
San Jose-
Sunnyvale-Santa
Clara, CAMSA
Latitude
and
Longitude
34.06659,
-118.22688
33.99958,
-117.41601
37.3485,
-121.895
Land Use
Residential
Residential
Commercial
Location
Setting
Urban/City
Center
Suburban
Urban/City
Center
Additional Ambient Monitoring Information1
TSP, TSP Speciation, Hexavalent chromium, CO,
SO2, NO, NO2, NOX, NOy, PAMS, Carbonyl
compounds, VOCs, O3, Meteorological parameters,
PM10, PM10 Speciation, PM2 5, PM25 Speciation.
Haze, TSP Speciation, Hexavalent chromium, CO,
SO2, NO, NO2, NOX, PAMS, VOCs, Carbonyl
compounds, O3, Meteorological parameters, PM10,
PM10 Speciation, PM coarse, PM25,
PM25 Speciation.
TSP Speciation, Hexavalent chromium, CO, SO2,
NO, NO2, NOX, VOCs, Carbonyl compounds, O3,
NMOC, Meteorological parameters, PM10, PM10
Speciation, Black carbon, PM2 5, PM2 5 Speciation.
Data for additional pollutants are reported to AQS for these sites (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this report
BOLD ITALICS = EPA-designated NATTS Site
oo
-------
CELA is located on the rooftop of a two-story building northeast of downtown Los
Angeles, just southeast of Dodgers' Stadium. Figure 6-1 shows that CELA is surrounded by
major freeways, including 1-5 and Route 110. Highway 101 is located farther south. Although
the area is classified as residential, a freight yard is located to the south of the site. The Los
Angeles River runs north-south just east of the site. This monitoring site was originally set up as
an emergency response monitor. As Figure 6-2 shows, CELA is situated among numerous point
sources. There is a cluster of emissions sources located just to the southwest of CELA. A large
number of emissions sources within 10 miles of CELA are involved in aircraft operations, which
include airports as well as small runways, heliports, or landing pads; furniture products;
electroplating, plating, polishing, anodizing, and coloring; and printing or publishing.
RUCA is located just outside of Riverside, in a residential area of the suburban town of
Rubidoux. Highway 60 runs east-west to the north of the site. Flabob Airport is located
approximately three-quarters of a mile to the southeast of the site. Figure 6-3 shows that RUCA
is adjacent to a power substation near the intersection of Mission Boulevard and Riverview
Drive. RUCA and CELA are located less than 45 miles apart. Figure 6-4 shows that fewer
emissions sources surround RUCA than CELA. Most of the emissions sources are located to the
northeast and northwest of the site. The point source located closest to RUCA is Flabob Airport.
The emissions source categories with the highest number of sources near RUCA include food
processing, aircraft operations, printing and publishing, and fabricated metals products.
SJJCA is located in central San Jose. Figure 6-5 shows that SJJCA is located in a
commercial area surrounded by residential areas. A railroad is shown just east of the monitoring
site, running north-south in Figure 6-5. Guadalupe Parkway, which can be seen on the bottom
left of Figure 6-5, intersects with 1-880 approximately 1 mile northwest of the monitoring site.
San Jose International Airport is just on the other side of this intersection. The Guadalupe River
runs along the eastern boundary of the airport and runs parallel to the Guadalupe Parkway.
Figure 6-6 shows that the density of point sources is significantly higher near SJJCA than CELA
and RUCA. The emissions source categories with the highest number of sources are electrical
equipment; auto body/paint shops; dry cleaning; and telecommunications.
6-9
-------
Table 6-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the California monitoring sites. Table 6-2 includes county-level
population and vehicle registration information. Table 6-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 6-2 also
contains traffic volume information for each site. Finally, Table 6-2 presents the county-level
daily VMT for Los Angeles, Riverside, and Santa Clara Counties.
Table 6-2. Population, Motor Vehicle, and Traffic Information for the California
Monitoring Sites
Site
CELA
RUCA
SJJCA
Estimated
County
Population1
9,889,056
2,239,620
1,809,378
County-level
Vehicle
Registration2
7,360,573
1,711,492
1,517,190
Vehicles per
Person
(Registration:
Population)
0.74
0.76
0.84
Population
within 10
miles3
3,557,102
1,026,542
1,482,077
Estimated
10-mile
Vehicle
Ownership
2,647,604
784,472
1,242,743
Annual
Average
Daily
Traffic4
230,000
145,000
104,000
County-
level Daily
VMT5
214,458,140
55,717,760
41,250,490
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the California DMV (CA DMV, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the California DOT (CA DOT, 2011)
5County-level VMT reflects 2011 data from the California DOT (CA DOT, 2012)
BOLD ITALICS = EPA-designated NATTS Site
Observations from Table 6-2 include the following:
Los Angeles County (CELA) has the highest county-level population and vehicle
registration compared to all counties with NMP sites. CELA also has the highest
10-mile estimated vehicle ownership. However, the 10-mile population near this site
ranks second behind MONY, which is located in Bronx County and part of New York
City.
Riverside and Santa Clara Counties are also in the top 10 for county-level population
and vehicle registration among counties with NMP sites.
Among the California sites, the vehicle-per-person ratio is lowest for the most
populous area (CELA) and highest for the least populated area (SJJCA), based on
county population, although all three sites are located in highly populated areas. In
general, this trend is also true among all NMP sites.
6-10
-------
CELA experiences the second highest annual average daily traffic among NMP sites,
and has a substantially higher traffic volume than both RUCA and SJJCA (although
all three rank in the top third among NMP sites). The traffic count for CELA is based
on data from 1-5 near Exit 136A at Main Street. The traffic count for RUCA is based
on data from Mission Boulevard at Rubidoux Boulevard. The traffic count for SJJCA
is based on the intersection of Guadalupe Parkway at West Taylor Street.
Los Angeles County's daily VMT is the highest among all counties with NMP sites,
where VMT was available. This VMT is an order of magnitude higher than the next
highest county-level VMT (Maricopa County, AZ). The VMT for Riverside and
Santa Clara Counties are also in the top 10 for VMT among counties with NMP sites
(where VMT data were available).
6.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in California on sample days, as well as over the course of the year.
6.2.1 Climate Summary
The climate of Los Angeles and the surrounding areas is generally mild. While the
proximity to the Pacific Ocean acts as a moderating influence on the Los Angeles area, the
elevation changes between the mountains and valleys allow the distance from the ocean to create
substantial differences in temperature, rainfall, and wind over a relatively short distance.
Precipitation falls primarily in winter months, while summers tend to be dry. Stagnant wind
conditions in the summer can result in air pollution episodes, while breezy Santa Ana winds can
create hot, dusty conditions. Fog and cloudy conditions are more prevalent near the coast than
farther inland (Bair, 1992 and WRCC, 2013).
San Jose is located to the southeast of San Francisco, near the base of the San Francisco
Bay. The city is situated in the Santa Clara Valley, between the Santa Cruz Mountains to the
south and west and the Diablo Range to the east. San Jose experiences a Mediterranean climate,
with distinct wet-dry seasons. The period from November through March represents the wet
season, with cool but mild conditions prevailing. Little rainfall occurs the rest of the year and
conditions tend to be warm and sunny. San Jose is not outside the marine influences of the cold
ocean currents typically affecting the San Francisco area (Bair, 1992 and NOAA, 1999).
6-11
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6.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather stations nearest these sites were
retrieved for 2010 and 2011 (NCDC, 2010 and 2011). The weather station nearest CELA is
located at Downtown Los Angeles/USC Campus; the nearest NWS weather station to RUCA is
located at Riverside Municipal Airport; and the nearest NWS station to SJJCA is located at San
Jose International (WBAN 93134, 03171, and 23293, respectively). Additional information
about these weather stations, such as the distance between the sites and the weather stations, is
provided in Table 6-3. These data were used to determine how meteorological conditions on
sample days vary from conditions experienced throughout the year.
Table 6-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. For SJJCA, meteorological data for the
additional days from 2010, as discussed in Section 2.3, have been included in the averages
presented in Table 6-3. Also included in Table 6-3 is the 95 percent confidence interval for each
parameter. As shown in Table 6-3, average meteorological conditions on sample days near these
sites were representative of average weather conditions throughout the year. The most significant
difference in the table is for average relative humidity for RUCA. Table 6-3 shows a marked
wind speed difference between CELA and RUCA (which are located 45 miles apart), as alluded
to in Section 6.2.1, although wind speeds for both sites are very light. As expected, conditions
tended to be cooler near SJJCA than near CELA and RUCA.
6-12
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Table 6-3. Average Meteorological Conditions near the California Monitoring Sites
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar
Wind
Speed
(kt)
Los Angeles, California - CELA
Downtown
L.A./USC Campus
Airport
93134
(34.03, -118.30)
4.57
miles
248ฐ
(WSW)
Sample
Day
2011
72.8
ฑ2.4
72.2
ฑ0.9
62.7
ฑ1.8
62.6
ฑ0.7
47.8
ฑ2.5
48.2
ฑ1.0
55.0
ฑ1.7
55.1
ฑ0.7
62.7
ฑ3.6
63.7
ฑ1.4
1015.0
ฑ1.0
1015.1
ฑ0.4
1.0
ฑ0.2
1.2
ฑ0.1
Rubidoux, California - RUCA
Riverside Municipal
Airport
03171
(33.95, -117.44)
3.49
miles
214ฐ
(SW)
Sample
Day
2011
78.3
ฑ3.5
77.9
ฑ1.3
64.8
ฑ2.6
64.3
ฑ1.0
42.3
ฑ3.6
43.8
ฑ1.3
53.6
ฑ2.1
53.8
ฑ0.8
51.5
ฑ4.4
54.2
ฑ1.7
1014.0
ฑ1.1
1014.1
ฑ0.4
3.8
ฑ0.4
3.8
ฑ0.2
San Jose, California - SJJCA
San Jose Intl.
Airport
23293
(37.36, -121.93)
1.90
miles
316ฐ
(NW)
Sample
Day
Dec
2010-
2011
69.4
ฑ2.3
68.7
ฑ1.0
58.6
ฑ1.7
58.2
ฑ0.8
46.5
ฑ2.1
46.5
ฑ0.9
52.4
ฑ1.6
52.2
ฑ0.7
67.9
ฑ2.9
68.6
ฑ1.2
1016.8
ฑ1.1
1016.8
ฑ0.5
4.9
ฑ0.5
5.3
ฑ0.2
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
6.2.3 Back Trajectory Analysis
Figure 6-7 is the composite back trajectory map for days on which samples were
collected at the CELA monitoring site in 2011. Included in Figure 6-7 are four back trajectories
per sample day. Figure 6-8 is the corresponding cluster analysis. Similarly, Figures 6-9 and 6-11
are the composite back trajectory maps for days on which samples were collected at RUCA and
SJJCA and Figures 6-10 and 6-12 are the corresponding cluster analyses, respectively. An in-
depth description of these maps and how they were generated is presented in Section 3.5.2.1. For
the composite maps, each line represents the 24-hour trajectory along which a parcel of air
traveled toward the monitoring site on a given sample day and time, based on an initial height of
50 meters AGL. For the cluster analyses, each line corresponds to a trajectory representative of a
given cluster of back trajectories. Each concentric circle around the sites in Figures 6-7 through
6-12 represents 100 miles.
Observations from Figures 6-7 and 6-8 for CELA include the following:
The 24-hour air shed domain for CELA is among the smaller ones compared to other
NMP monitoring sites, based on the average length of trajectories. Although the
farthest away a trajectory originated was over southwest Montana, or greater than
800 miles away, most trajectories (83 percent) originated within 300 miles of CELA
(and only eight back trajectories originated greater than 500 miles away).
Back trajectories originated from a variety of directions at CELA. However, a large
number of trajectories originated from the northwest over the Pacific Ocean and along
the California coastline. Another cluster originated from the east-northeast. Few
trajectories originated from the east, southeast, south, or southwest. The longest back
trajectories originated to the northeast of the site.
The cluster analysis shows that roughly 70 percent of trajectories originated from the
northwest and/or offshore, although of varying distances. The shorter cluster
trajectory (19 percent) includes back trajectories originating to the northwest of Los
Angeles as well as shorter trajectories originating just offshore. The cluster analysis
also shows that 25 percent of trajectories originated from the northeast quadrant
(including northerly and easterly directions). The long cluster (3 percent) originating
over Idaho represents the longer trajectories originating over northeast Utah, Idaho,
and Montana.
6-14
-------
Figure 6-7. 2011 Composite Back Trajectory Map for CELA
Figure 6-8. Back Trajectory Cluster Map for CELA
6-15
-------
Figure 6-9. 2011 Composite Back Trajectory Map for RUCA
Figure 6-10. Back Trajectory Cluster Map for RUCA
6-16
-------
Figure 6-11. 2011 Composite Back Trajectory Map for SJJCA
Figure 6-12. Back Trajectory Cluster Map for SJJCA
6-17
-------
Observations from Figures 6-9 and 6-10 for RUCA include the following:
The composite back trajectory map for RUCA resembles the one for CELA, which is
not surprising given their relatively close proximity. The 24-hour air shed domain for
RUCA is similar in size to CELA. The farthest away a trajectory originated was also
over western Montana, or greater than 850 miles away. Most trajectories (86 percent)
originated within 300 miles of RUCA and only eight trajectories originated farther
than 500 miles away.
Back trajectories originated from a variety of directions at RUCA. A large cluster of
trajectories originated from the northwest of the site and a secondary cluster
originated from the northeast. Few trajectories originated from the east, southeast, or
south. The longest back trajectories originated to the northeast of the site.
The cluster analysis for RUCA is similar to the cluster analysis for CELA.
Figure 6-10 shows that nearly 70 percent of trajectories originated from the northwest
of the site. However, the shorter trajectory (31 percent) includes some back
trajectories originating from the northwest along the coastline and offshore as well as
shorter trajectories originating from the west (either offshore or inland, as the
clustering program uses both direction and distance to determine clusters). Another
cluster (29 percent) represents those trajectories originating from the north, northeast,
and east over southern California, southern Nevada, northwest Arizona, and
southwest Utah. The long cluster trajectory marked with 3 percent represents the
eight back trajectories originating over the inter-mountain west.
Observations from Figures 6-11 and 6-12 for SJJCA include the following:
Based on the average length of the back trajectories, the 24-hour air shed domain for
SJJCA is somewhat larger than the air shed domains for the other two California
sites. The farthest away a back trajectory originated was also over western Montana
or just greater than 700 miles away, which is shorter than the longest back trajectories
for CELA and RUCA. Only 71 percent of back trajectories originated within
300 miles of SJJCA, while greater than 80 percent originated within 300 miles of
CELA and RUCA. Eight back trajectories originated farther than 500 miles away
from the site. Recall from Section 2.3, that three additional sample days from
December 2010 are included in the composite back trajectory map for SJJCA.
Back trajectories originated from a variety of directions at SJJCA, seemingly more so
than for the other two California sites. However, the composite map still shows a
large number of trajectories originated from the northwest and along the coast. Fewer
back trajectories originated from the southeast quadrant.
The cluster analysis shows that 50 percent of trajectories originated from the
northwest to northeast, with the cluster program grouping those from the northwest,
north, and northeast together. Back trajectories originating from the northeast to east
to southeast are represented by the cluster trajectory originating to the east
(14 percent). The short cluster (18 percent) originating just offshore includes back
trajectories less than 200 miles in length from a variety of directions as well as those
longer trajectories originating from the south. Fifteen percent of back trajectories
6-18
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originated farther offshore. The longest trajectory (3 percent) includes the eleven
trajectories originating over the Pacific Northwest and Idaho.
6.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations at the Downtown Los
Angeles/USC Campus (for CELA), Riverside Municipal Airport (for RUCA), and San Jose
International Airport (for SJJCA) were uploaded into a wind rose software program to produce
customized wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind
directions using "petals" positioned around a 16-point compass, and uses different colors to
represent wind speeds.
Figure 6-13 presents a map showing the distance between the NWS station and CELA,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 6-13 also presents three different wind roses for the
CELA monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
to determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figures 6-14 and 6-15 present the distance maps and wind
roses for RUCA and SJJCA, respectively.
6-19
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Figure 6-13. Wind Roses for the Downtown Los Angeles/USC Campus Weather Station
near CELA
Distance between CELA and NWS Station
2001-2010 Historical Wind Rose
WIND SPEED
(Knots)
n ซ=
^| 17 21
JH 11 - 17
H I-7
! 2- 4
Calms: 33.72%
2011 Wind Rose
Sample Day Wind Rose
_
,,."-*""""""
^^^^p^^
WEST ; -T
v",%
NORTH'---.,
""S 10%
*"*% 6%-%
4%,
f 2% '; ! !
CJ---A t >
^>T ; I IEAST
WEST ^ *^~*
,""" '' ' WIND SPEED \ \ ""---....
(Knots) '\ %v-,
..-'' ,'' I I ซ22 *-, "'--
-"''
SOUTH---'" --
17-21 *~-v>
11 - 17 ~---------
NORTH''---,
10%
""-^ 8%,
""--,^ 6%-s
4*,
2% ': ';
^T"; : : EAST
^'' / / WND SPEED
(Knots)
.,-""' ,-'' n -22
^| 17-21
SOUTH---"' 11'17
7- 11 ^^
D 4-7
4- 7 ^_
2- 4
2- 4
Calm;: ?2^:i'S.
Calms: 89.39%
6-20
-------
Figure 6-14. Wind Roses for the Riverside Municipal Airport Weather Station near RUCA
Distance between RUCA and NWS Station
2001-2010 Historical Wind Rose
WIND SPEED
(Knots)
|| >= 22
^| 17 21
^| 11 17
Calms: 30.74%
2011 Wind Rose
ND SPEED
(Knots)
cn 4-7
Calms: 35.16%
Sample Day Wind Rose
WIND SPEED
(Knots)
|1 >= 22
^| 17 - 21
^| 11 17
IB 7- 11
| | 4- 7
IB 2- 4
Calms: 33.88%
6-21
-------
Figure 6-15. Wind Roses for the San Jose International Airport Weather Station near
SJJCA
Distance between SJJCA and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
6-22
-------
Observations from Figure 6-13 for CELA include the following:
The NWS weather station at the Downtown Los Angeles/USC Campus is located
approximately 4.6 miles west-southwest of CELA.
Historically, winds were generally light near this site, with calm winds (< 2 knots)
observed for nearly 60 percent of the wind observations. For wind speeds greater than
2 knots, westerly winds were most common, followed by west-southwesterly and
easterly winds. Wind speeds greater than 11 knots were not measured at this weather
station.
The 2011 full-year and sample day wind roses are similar to the historical wind rose
in that calm winds make up the bulk of the observations and that westerly winds were
prominent. The wind patterns shown on the full-year and sample day wind roses
generally resemble the historical wind patterns, indicating that conditions in 2011 and
on sample days were representative of those experienced historically. However, west-
southwesterly winds were rarely observed in 2011.
Observations from Figure 6-14 for RUCA include the following:
The NWS weather station at the Riverside Municipal Airport is located across the
Santa Ana River and Wildlife Area, approximately 3.5 miles southwest of RUCA.
Although calm winds were observed for approximately 31 percent of the wind
observations near RUCA, westerly and west-northwesterly winds were also
frequently observed, based on the historical wind rose.
The 2011 wind rose exhibits a slightly higher percentage of calm winds compared to
the historical wind rose. Westerly winds make up almost the same percentage of wind
observations in 2011 as both westerly and west-northwesterly winds on the historical
wind rose, as west-northwesterly winds were observed less frequently in 2011 than
historically.
The wind patterns shown on the sample day wind rose resemble the wind patterns
shown on the full-year wind rose, indicating that conditions on sample days were
representative of those experienced over the entire year.
Observations from Figure 6-15 for SJJCA include the following:
The NWS weather station at the San Jose International Airport is located
approximately 2 miles northwest of SJJCA, across 1-880, the Guadalupe Parkway,
and the Guadalupe River.
Between 2001 and 2010, approximately 47 percent of winds were from the west-
northwest to north. Another 20 percent of winds were from the east-southeast to
south. Winds from the northeastern and southwestern quadrants were rarely observed.
Approximately one-fifth of the winds were calm.
6-23
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The additional days from December 2010 have been included in the 2011 full-year
and sample day wind roses, as discussed in Section 2.3.
The wind patterns on the full-year and sample day wind roses exhibit a shift in
primary wind direction, from northwest to north on the historical wind rose to west to
northwest on the 2011 wind roses. This shift is also shown in the secondary wind
directions, from southeast to south on the historical to east-southeast to southeast on
the 2011 wind roses. This shift was also shown on the 2009 and 2010 wind roses in
the 2008-2009 and 2010 NMP reports.
The wind patterns shown on the sample day wind rose resemble the wind patterns
shown on the full-year wind rose, indicating that conditions on sample days were
representative of those experienced over the entire year.
6.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the California monitoring sites
in order to allow analysts and readers to focus on a subset of pollutants through the context of
risk. For each site, each pollutant's preprocessed daily measurement was compared to its
associated risk screening value. If the concentration was greater than the risk screening value,
then the concentration "failed the screen." Pollutants of interest are those for which the
individual pollutant's total failed screens contribute to the top 95 percent of the site's total failed
screens. In addition, if any of the NATTS MQO Core Analytes measured by each monitoring site
did not meet the pollutant of interest criteria based on the preliminary risk-based screening, that
pollutant was added to the list of site-specific pollutants of interest. A more in-depth description
of the risk-based screening process is presented in Section 3.2.
Table 6-4 presents the results of the preliminary risk-based screening process for CELA,
RUCA, and SJJCA. The pollutants that failed at least one screen and contributed to 95 percent of
the total failed screens for each monitoring site are shaded. NATTS MQO Core Analytes are
bolded. Thus, pollutants of interest are shaded and/or bolded. CELA and RUCA sampled for
PAHs only, while SJJCA sampled for metals (PMio) and PAHs.
6-24
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Table 6-4. Risk-Based Screening Results for the California Monitoring Sites
Pollutant
Screening
Value
(Hg/m3)
# of Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Los Angeles, California - CELA
Naphthalene
Acenaphthene
Fluorene
0.029
0.011
0.011
Total
58
3
3
64
59
59
59
177
98.31
5.08
5.08
36.16
90.63
4.69
4.69
90.63
95.31
100.00
Rubidoux, California - RUCA
Naphthalene
0.029
Total
54
54
61
61
88.52
88.52
100.00
100.00
San Jose, California - SJJCA
Naphthalene
Arsenic (PM10)
Manganese (PM10)
Nickel (PM10)
Benzo(a)pyrene
Acenaphthylene
0.029
0.00023
0.005
0.0021
0.00057
0.011
Total
52
43
35
8
3
2
143
61
63
64
64
19
27
298
85.25
68.25
54.69
12.50
15.79
7.41
47.99
36.36
30.07
24.48
5.59
2.10
1.40
36.36
66.43
90.91
96.50
98.60
100.00
Observations from Table 6-4 include the following:
Naphthalene failed the majority of screens for all three California monitoring sites,
with its site-specific contribution to the total failed screens ranging from 36 percent
(SJJCA) to 100 percent (RUCA).
Three pollutants failed screens for CELA, including one NATTS MQO Core Analyte
(naphthalene). Benzo(a)pyrene was added to the pollutants of interest for CELA
because it is a NATTS MQO Core Analyte, even though it did not fail any screens.
Benzo(a)pyrene is not shown in Table 6-4 but is shown in subsequent tables in the
sections that follow.
Naphthalene was the only pollutant to fail screens for RUCA. Similar to CELA,
benzo(a)pyrene was added to RUCA's pollutants of interest because it is a NATTS
MQO Core Analyte, even though it did not fail any screens. Benzo(a)pyrene is not
shown in Table 6-4 but is shown in subsequent tables in the sections that follow.
Six pollutants failed screens for SJJCA, of which five are NATTS MQO Core
Analytes. Four of these were initially identified as pollutants of interest for SJJCA.
Benzo(a)pyrene was added as a pollutant of interest, even though it did not contribute
to 95 percent of SJJCA's total failed screens, because it is a NATTS MQO Core
Analyte. Three additional NATTS MQO Core Analytes were added to the pollutants
of interest for SJJCA, even though their concentrations did not fail any screens:
beryllium, cadmium, and lead. These three pollutants are not shown in Table 6-4, but
are shown in subsequent tables in the sections that follow.
6-25
-------
The instrumentation at SJJCA for sampling metals was changed in mid-December
2010 and the site began sampling metals on Teflonฎ filters rather than quartz filters.
In light of this change, the three samples from 2010 on the new instrumentation were
included in all data analyses contained in this report.
6.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the California monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the California monitoring sites, where the data meet the
applicable criteria. Concentration averages for select pollutants are also presented graphically for
the sites to illustrate how the sites' concentrations compare to the program-level averages, as
presented in Section 4.1. In addition, concentration averages for select pollutants are presented
from previous years of sampling in order to characterize concentration trends at the sites.
Additional site-specific statistical summaries for CELA, RUCA, and SJJCA are provided in
Appendices M and N.
6.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each California site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the California
monitoring sites are presented in Table 6-5, where applicable. Note that if a pollutant was not
detected in a given calendar quarter, the quarterly average simply reflects "0" because only zeros
substituted for non-detects were factored into the quarterly average concentration. Note also that
the three December 2010 metals samples for SJJCA have been included in the first quarter
averages shown in Table 6-5.
6-26
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Table 6-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest
for the California Monitoring Sites
Pollutant
#of
Measured
Detections vs.
# of Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Los Angeles, California - CELA
Acenaphthene
Benzo(a)pyrene
Fluorene
Naphthalene
59/59
41/59
59/59
59/59
3.96
ฑ1.25
0.06
ฑ0.02
4.92
ฑ1.25
160.49
ฑ50.18
3.89
ฑ1.11
0.02
ฑ0.01
4.69
ฑ1.22
78.35
ฑ 22.87
6.06
ฑ1.39
0.03
ฑ0.01
6.54
ฑ1.42
118.30
ฑ 30.47
5.83
ฑ2.18
0.12
ฑ0.05
6.37
ฑ1.78
173.46
ฑ51.51
4.92
ฑ0.76
0.06
ฑ0.02
5.62
ฑ0.70
131.96
ฑ21.23
Rubidoux, California - RUCA
Benzo(a)pyrene
Naphthalene
25/61
61/61
0.02
ฑ0.01
80.99
ฑ26.99
0.01
ฑ0.01
55.39
ฑ 17.96
0.01
ฑ0.01
85.68
ฑ 24.06
0.08
ฑ0.06
143.05
ฑ50.61
0.03
ฑ0.02
91.18
ฑ17.14
San Jose, California - SJJCA
Arsenic (PM10)
Benzo(a)pyrene
Bery Ilium (PM10)
Cadmium (PM10)
Lead (PM10)
Manganese (PM10)
Naphthalene
Nickel (PM10)
63/64
19/61
55/64
64/64
64/64
64/64
61/61
64/64
0.41
ฑ0.17
0.09
ฑ0.05
0.01
ฑ<0.01
0.07
ฑ0.03
2.78
ฑ1.19
5.78
ฑ2.19
103.53
ฑ44.91
1.09
ฑ0.36
0.24
ฑ0.07
0
0.01
ฑ<0.01
0.04
ฑ0.01
1.73
ฑ0.43
4.00
ฑ0.95
34.63
ฑ8.01
1.05
ฑ0.27
0.32
ฑ0.09
0.01
ฑ0.01
0.01
ฑ<0.01
0.04
ฑ0.01
2.70
ฑ1.09
6.70
ฑ1.55
45.44
ฑ 10.88
1.35
ฑ0.29
0.61
ฑ0.14
0.20
ฑ0.17
0.01
ฑ<0.01
0.13
ฑ0.05
4.92
ฑ1.07
10.19
ฑ3.12
138.94
ฑ42.95
1.61
ฑ0.38
0.39
ฑ0.07
0.07
ฑ0.05
0.01
ฑ<0.01
0.07
ฑ0.02
3.02
ฑ0.56
6.62
ฑ1.14
80.06
ฑ 18.30
1.27
ฑ0.17
Observations for the California monitoring sites from Table 6-5 include the following:
Naphthalene and benzo(a)pyrene are pollutants of interest for each site.
The pollutant with the maximum annual average concentration for each site is
naphthalene, which ranged from 80.06 ฑ 18.30 ng/m3 for SJJCA to
131.96 ฑ 21.23 ng/m3 for CELA. The naphthalene concentrations for SJJCA exhibit a
seasonal trend, with higher concentrations measured during the colder months of the
year (first and fourth quarters). Naphthalene concentrations for CELA appear to
exhibit this trend too, although the difference in the quarterly averages is not
statistically significant. Naphthalene concentrations for RUCA appear highest during
the fourth quarter, but the relatively high confidence interval associated with this
average indicates the possible influence of outliers.
6-27
-------
Benzo(a)pyrene concentrations also appear to be higher during the colder months of
the year, particularly for SJJCA. However, this pollutant was detected in just over
one-quarter of the samples collected at SJJCA. Benzo(a)pyrene was not detected at all
during the second quarter at SJJCA and was detected only twice during the third
quarter of 2011.
Manganese has the highest annual average concentration (6.62 ฑ1.14 ng/m3) of the
PMio metals measured at SJJCA. The quarterly averages for manganese show that the
highest concentrations were measured during the fourth quarter of 2011. A review of
the data shows that of the 11 concentrations of manganese greater than 10 ng/m3
measured at this site, seven were measured during the fourth quarter of 2011,
including the two highest concentrations (25.4 ng/m3 measured on November 2, 2011
and 18.1 ng/m3 measured on October 27, 2011).
The highest quarterly average concentration was calculated for the fourth quarter of
2011 for most of the PMio metals.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the
California sites from those tables include the following:
CELA appears in Table 4-11 for PAHs three times. CELA has the fourth highest
annual average concentration naphthalene among NMP sites sampling PAHs, behind
GPCO, DEMI, and MONY. This site also ranks eighth for acenaphthene and
fluorene, but does not appear in Table 4-11 for benzo(a)pyrene (it ranks 14th). RUCA
has the ninth highest annual average concentration of naphthalene and tenth highest
annual average concentration of fluorene. SJJCA does not appear in Table 4-11.
Because only nine sites sampled PMio metals, SJJCA appears in Table 4-12 for every
program-level metal pollutant of interest. However, this site was not in the top five
for any of the speciated metals.
6.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzo(a)pyrene and
naphthalene were created for all three California sites. Box plots were also created for arsenic,
lead, and manganese for SJJCA. Figures 6-16 through 6-20 overlay the sites' minimum, annual
average, and maximum concentrations onto the program-level minimum, first quartile, median,
average, third quartile, and maximum concentrations, as described in Section 3.5.3.
6-28
-------
Figure 6-16. Program vs. Site-Specific Average Arsenic (PMi0) Concentration
SJJCA
DL5
1.5
2 2.5
Concentration (ng/mi)
3.5
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile 3rdQuartile 4thQuartile Avc
n
Site Minimum/Maximum
'rage
4.5
Figure 6-17. Program vs. Site-Specific Average Benzo(a)pyrene Concentrations
CELA
i
0.75 1 1.Z5
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 6-18. Program vs. Site-Specific Average Lead (PMio) Concentration
15 20
Concentration (ng/m3)
Program
Site:
: IstQuartile
Site Average
0
2ndQuartile SrdQuartile 4thQuartile Ave
n
Site Minimum/Maximum
rage
6-29
-------
Figure 6-19. Program vs. Site-Specific Average Manganese (PMi0) Concentration
SJJCA
Program Max Concentration = 395 ng/m3
75 100 125
Concentration (ng/m3)
ISO
175
200
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
o
Figure 6-20. Program vs. Site-Specific Average Naphthalene Concentrations
CELA
[ Program Max Concentration =779 ng/m3
: P rogra m M a x Co n ce ntratio n = 779 ng/m3
1 i Program Max Concentration = 779 ng/m3
200 250 300
Concentration (ng/m3)
Program
Site:
: IstQuartile
Site Average
O
2ndQuartile SrdQuartile 4thQuartile Ave
Site Minimum/Maximum
rage
Observations from Figures 6-16 through 6-20 include the following:
Figure 6-16 shows that the annual average arsenic (PMio) concentration for
SJJCA is less than the program-level average and median concentrations of
arsenic (PMio). A single non-detect of arsenic was measured at SJJCA.
Figure 6-17 for benzo(a)pyrene shows all three sites. Note that the program-level
first quartile for this pollutant is zero and is not visible on the box plots. Each of
the annual average concentrations of benzo(a)pyrene for the California sites is
less than the program-level average concentration. Figure 6-17 also shows that
while the maximum benzo(a)pyrene concentration measured at each California
site is less than the maximum concentration measured across the program, the
maximum concentration measured at SJJCA is more than twice the maximum
concentration measured at RUCA and three times the maximum concentration
6-30
-------
measured at CELA. Non-detects of benzo(a)pyrene were reported for each of
these three sites.
Figure 6-18 shows that the annual average concentration of lead (PMio) for
SJJCA is less than the program-level average and but greater than the program-
level median concentration. The maximum lead concentration measured at SJJCA
is less than the maximum concentration measured across the program. There were
no non-detects of lead measured at SJJCA or across the program.
Figure 6-19 is the box plot for manganese (PMio). Note that the program-level
maximum concentration (395 ng/m3) is not shown directly on the box plot
because the scale of the box plot would be too large to readily observe data points
at the lower end of the concentration range. Thus, the scale has been reduced to
200 ng/m3. Figure 6-19 shows that the annual average concentration of
manganese (PMio) for SJJCA is also less than the program-level average
concentration. The maximum manganese concentration measured at SJJCA is
considerably less than the maximum concentration measured across the program.
There were no non-detects of manganese measured at SJJCA or across the
program.
Figure 6-20 for naphthalene also shows all three sites. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 500 ng/m3 to allow for the observation of data points at
the lower end of the concentration range. Figure 6-20 shows that the annual
average concentrations for CELA and RUCA are greater than the program-level
average concentration, while the annual average concentration for SJJCA is just
less than the program-level average. Figure 6-20 also shows that the maximum
concentrations for all three sites are less than the maximum concentration
measured across the program. However, CELA's maximum concentration
(430 ng/m3) is the fifth highest concentration measured among sites sampling
PAHs. There were no non-detects of naphthalene measured at CELA, RUCA, or
SJJCA or across the program.
6.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. Although both CELA and RUCA began sampling PAHs in 2007, they did not
begin until April and May, respectively, and therefore average concentrations could not be
calculated for 2007. SJJCA did not begin sampling under the NMP until 2008. Therefore, the
trends analysis was not conducted for the California sites.
6-31
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6.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each California monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
6.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
California monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
6.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the California sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 6-6, where applicable. Cancer risk approximations
are presented as probabilities while the noncancer hazard approximations are ratios and thus,
unitless values.
6-32
-------
Table 6-6. Risk Approximations for the California Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Los Angeles, California - CELA
Acenaphthene
Benzo(a)pyrene
Fluorene
Naphthalene
0.000088
0.00176
0.000088
0.000034
0.003
59/59
41/59
59/59
59/59
4.92
ฑ0.76
0.06
ฑ0.02
5.62
ฑ0.70
131.96
ฑ21.23
0.43
0.10
0.49
4.49
0.04
Rubidoux, California - RUCA
Benzo(a)pyrene
Naphthalene
0.00176
0.000034
0.003
25/61
61/61
0.03
ฑ0.02
91.18
ฑ17.14
0.05
3.10
0.03
San Jose, California - SJJCA
Arsenic (PM10)
Benzo(a)pyrene
Beryllium (PM10)
Cadmium (PM10)
Lead (PM10)
Manganese (PM10)
Naphthalene
Nickel (PM10)
0.0043
0.00176
0.0024
0.0018
0.000034
0.00048
0.000015
0.00002
0.00001
0.00015
0.00005
0.003
0.00009
63/64
19/61
55/64
64/64
64/64
64/64
61/61
64/64
0.39
ฑ0.07
0.07
ฑ0.05
0.01
ฑ0.01
0.07
ฑ0.02
3.02
ฑ0.56
6.62
ฑ1.14
80.06
ฑ 18.30
1.27
ฑ0.17
1.69
0.13
0.02
0.13
2.72
0.61
0.03
0
0.01
0.02
0.13
0.03
0.01
= a Cancer URE or Noncancer RfC is not available.
Observations for the California sites from Table 6-6 include the following:
Naphthalene has the highest annual average concentration for each of the California
sites, as discussed in the previous section.
Naphthalene also has the highest cancer risk approximation among the pollutants of
interest for all three California monitoring sites. The cancer risk approximations range
from 2.72 in-a-million for SJJCA to 4.49 in-a-million for CELA.
Of the metals sampled at SJJCA, arsenic has the highest cancer risk approximation
and is the only metal for which a cancer risk approximation is greater than
1.0 in-a-million (1.69 in-a-million).
6-33
-------
All of the noncancer hazard approximations for the pollutants of interest for the
California monitoring sites are less than 1.0, indicating that no adverse health effects
are expected from these individual pollutants.
6.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 6-7 and 6-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 6-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages and provided
in Table 6-6. Table 6-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 6-6.
The pollutants listed in Tables 6-7 and 6-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 6.3, all three California monitoring sites sampled for PAHs and SJJCA also sampled
PMio metals. In addition, the cancer risk and noncancer hazard approximations are limited to
those pollutants with enough data to meet the criteria for annual averages to be calculated. A
more in-depth discussion of this analysis is provided in Section 3.5.5.3. Similar to the cancer risk
and noncancer hazard approximations, this analysis may help policy-makers prioritize their air
monitoring activities.
6-34
-------
Table 6-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the California Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Cancer Risk
Approximation
Pollutant (in-a-million)
Los Angeles, California (Los Angeles County) - CELA
Formaldehyde
Benzene
Dichloromethane
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
ฃ>-Dichlorobenzene
Tetrachloroethylene
Trichloroethylene
3,019.71
1,847.23
1,347.58
1,236.99
959.04
358.22
207.88
144.14
105.99
50.40
Formaldehyde
Hexavalent Chromium, PM
Benzene
1,3 -Butadiene
Naphthalene
Arsenic, PM
Nickel, PM
Acetaldehyde
Ethylbenzene
POM, Group la
3.93E-02
2.57E-02
1.44E-02
1.07E-02
7.07E-03
5.28E-03
5.01E-03
2.72E-03
2.40E-03
1.99E-03
Naphthalene 4.49
Fluorene 0.49
Acenaphthene 0.43
Benzo(a)pyrene 0.10
Rubidoux, California (Riverside County) - RUCA
Formaldehyde
Benzene
Acetaldehyde
Ethylbenzene
Tetrachloroethylene
Dichloromethane
1,3 -Butadiene
Naphthalene
1 ,3 -Dichloropropene
ฃ>-Dichlorobenzene
793.92
409.04
353.08
207.95
163.53
150.35
81.30
55.49
37.72
28.62
Hexavalent Chromium, PM
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
Arsenic, PM
Acetaldehyde
POM, Group la
Ethylbenzene
Nickel, PM
2.13E-02
1.03E-02
3.19E-03
2.44E-03
1.89E-03
1.82E-03
7.77E-04
5.85E-04
5.20E-04
4.85E-04
Naphthalene 3.10
Benzo(a)pyrene 0.05
-------
Table 6-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the California Monitoring Sites (Continued)
Oi
OJ
Oi
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
San Jose, California (Santa Clara County) - SJJCA
Formaldehyde
Benzene
Acetaldehyde
Ethylbenzene
Dichloromethane
Tetrachloroethylene
1,3 -Butadiene
Naphthalene
ฃ>-Dichlorobenzene
POM, Group la
577.88
353.73
254.78
201.33
102.75
97.93
74.71
39.30
25.48
19.28
Formaldehyde
Hexavalent Chromium, PM
Benzene
1,3 -Butadiene
POM, Group la
Naphthalene
Arsenic, PM
Acetaldehyde
Ethylbenzene
Nickel, PM
7.51E-03
7.13E-03
2.76E-03
2.24E-03
1.70E-03
1.34E-03
9.76E-04
5.61E-04
5.03E-04
2.82E-04
Naphthalene
Arsenic
Nickel
Benzo(a)pyrene
Cadmium
Beryllium
2.72
1.69
0.61
0.13
0.13
0.02
-------
Table 6-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the California Monitoring Sites
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Los Angeles, California (Los Angeles County) - CELA
1,1,1 -Trichloroethane
Toluene
Formaldehyde
Benzene
Dichloromethane
Hexane
Acetaldehyde
Ethylbenzene
Xylenes
Ethylene glycol
7,345.47
5,503.09
3,019.71
1,847.23
1,347.58
1,286.59
1,236.99
959.04
873.15
655.71
Acrolein
Chlorine
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Nickel, PM
Arsenic, PM
Hexamethylene- 1 ,6-diisocyanate, gas
Naphthalene
Benzene
8,698,970.49
367,827.04
308,133.92
179,110.50
137,443.72
115,985.91
81,886.64
78,379.05
69,291.67
61,574.38
Naphthalene 0.04
Rubidoux, California (Riverside County) - RUCA
Toluene
1,1,1 -Trichloroethane
Formaldehyde
Benzene
Acetaldehyde
Hexane
Ethylbenzene
Xylenes
Tetrachloroethylene
Dichloromethane
1,289.54
807.28
793.92
409.04
353.08
300.78
207.95
178.62
163.53
150.35
Acrolein
Chlorine
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Arsenic, PM
Naphthalene
Hexavalent Chromium, PM
Bromomethane
Benzene
1,964,801.08
87,536.25
81,012.73
40,650.19
39,230.78
28,239.83
18,496.03
17,714.98
16,899.96
13,634.82
Naphthalene 0.03
-------
Table 6-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the California Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
San Jose, California (Santa Clara County) - SJJCA
Toluene
1,1,1 -Trichloroethane
Formaldehyde
Benzene
Hexane
Acetaldehyde
Ethylbenzene
Xylenes
Ethylene glycol
Propionaldehyde
1,394.35
1,290.78
577.88
353.73
265.48
254.78
201.33
176.68
120.59
113.19
Acrolein
Chlorine
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Arsenic, PM
Propionaldehyde
Naphthalene
Benzene
Lead, PM
1,999,590.36
109,927.46
58,967.45
37,354.73
28,308.52
15,130.81
14,149.25
13,100.12
11,790.92
10,622.90
Manganese
Arsenic
Naphthalene
Lead
Nickel
Cadmium
Beryllium
0.13
0.03
0.03
0.02
0.01
0.01
0.01
oo
-------
Observations from Table 6-7 include the following:
Formaldehyde and benzene are the two highest emitted pollutants with cancer UREs
in all three California counties. The quantity emitted is greater for Los Angeles
County than Riverside and Santa Clara Counties.
Formaldehyde and hexavalent chromium are the pollutants with the highest toxicity-
weighted emissions (of the pollutants with cancer UREs) for Los Angeles and Santa
Clara Counties, while the order is reversed for Riverside County.
Six of the highest emitted pollutants also have the highest toxi city-weighted
emissions for Los Angeles and Riverside Counties, while there are seven in common
for Santa Clara County. While hexavalent chromium is at or near the top in toxicity-
weighted emissions for all three counties, this pollutant is not among the 10 highest
emitted pollutants in these counties. Hexavalent chromium emissions rank between
13th highest for RUCA to 18th highest for SJJCA.
Naphthalene has the highest cancer risk approximation for all three sites. Naphthalene
is the only pollutant to appear on all three lists for all three counties.
Arsenic and nickel, which have the second and third highest cancer risk
approximations for SJJCA, respectively, have the seventh and tenth highest toxicity-
weighted emissions for Santa Clara County, but are not among the 10 highest emitted
pollutants for this county. These are the only pollutants sampled by SJJCA, other than
naphthalene, to appear on either emissions-based list.
Observations from Table 6-8 include the following:
Toluene, 1,1,1-trichloroethane, formaldehyde, and benzene are the highest emitted
pollutants with noncancer RfCs in all three California counties (although not
necessarily in that order). Consistent with pollutants having cancer UREs, emissions
are greater in Los Angeles County than Riverside and Santa Clara Counties.
Acrolein, chlorine, and formaldehyde are the pollutants with the highest toxicity-
weighted emissions (of the pollutants with noncancer RfCs) for all three counties.
While acrolein and chlorine rank highest for toxicity-weighted emissions for each
county, neither pollutant appears among the highest emitted. Conversely,
formaldehyde has the third highest emissions for each county.
Three of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Los Angeles and Riverside Counties, while four of the highest emitted
pollutants also have the highest toxicity-weighted emissions for Santa Clara County.
Naphthalene, the only pollutant for which a noncancer hazard approximation could be
calculated for CELA and RUCA, has one of the 10 highest toxicity-weighted
emissions for these sites' respective counties, but does not appear on the list of the 10
highest total emissions for either county (of pollutants with noncancer RfCs). This is
also true for Santa Clara County.
6-39
-------
Besides naphthalene, arsenic and lead are the only two pollutants for which
noncancer hazard approximations could be calculated for SJJCA and that also appear
on the list of 10 highest toxi city-weighted emissions. Manganese, which has the
highest noncancer hazard approximation for SJJCA, appears on neither emissions-
based list. None of the metals appear among the pollutants with the highest total
emissions.
6.6 Summary of the 2011 Monitoring Data for CELA, RUCA, and SJJCA
Results from several of the data treatments described in this section include the
following:
ปซป Three PAHs, including naphthalene, failed screens for CELA, while only naphthalene
failed screens for RUCA. Three PAHs and three PMw metals failed screens for
SJJCA.
ปซป Naphthalene had the highest annual average concentration among all the pollutants
of interest for the California sites. Among the metals sampled at SJJCA, manganese
had the highest annual average concentration.
ปซป Concentrations of naphthalene and benzo(a)pyrene exhibit a seasonal trend at
SJJCA, with higher concentrations during the first and fourth quarters (or the colder
months) of 2011.
6-40
-------
7.0 Sites in Colorado
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS and UATMP sites in Colorado, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
7.1 Site Characterization
This section characterizes the Colorado monitoring sites by providing geographical and
physical information about the location of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
The NATTS site is located in Grand Junction (GPCO) and the other four sites are located
in Garfield County, between 35 and 55 miles northeast of Grand Junction, in the towns of
Battlement Mesa (BMCO), Silt (BRCO), Parachute (PACO), and Rifle (RICO). Figure 7-1 for
GPCO and Figures 7-3 through 7-6 for the Garfield County sites are composite satellite images
retrieved from ArcGIS Explorer showing the monitoring sites in their urban and rural locations.
Figures 7-2 and 7-7 identify nearby point source emissions locations by source category, as
reported in the 2008 NEI for point sources. Note that only sources within 10 miles of each site
are included in the facility counts provided in Figures 7-2 and 7-7. A 10-mile boundary was
chosen to give the reader an indication of which emissions sources and emissions source
categories could potentially have a direct effect on the air quality at the monitoring sites. Further,
this boundary provides both the proximity of emissions sources to the monitoring sites as well as
the quantity of such sources within a given distance of the sites. Sources outside the 10-mile radii
are still visible on the maps, but have been grayed out in order to show emissions sources just
outside the boundary. Table 7-1 provides supplemental geographical information such as land
use, location setting, and locational coordinates.
7-1
-------
Figure 7-1. Grand Junction, Colorado (GPCO) Monitoring Site
to
-------
Figure 7-2. NEI Point Sources Located Within 10 Miles of GPCO
0 2.5 5 10
I 1 1 1 1 1 1 1 1
MM
Legend
GPCO NATTS site
10 mile radius
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
County boundary
Source Category Group (No. of Facilities)
41 Aircraft Operations (9)
0 Auto Body Shop/Painters (4)
SS Automobile/Truck Manufacturing (2)
Brick Manufacturing & Structural Clay (1)
B Bulk Terminals/Bulk Plants (4)
C Chemical Manufacturing (1)
Concrete Batch Plant (6)
X Crematory-Animal/Human (4)
(1) Dry Cleaning (4)
e Electrical Equipment (2)
E Electroplating. Plating. Polishing, Anodizing, and Coloring (2)
ฉ Fabricated Metal Products (1)
E! Furniture Plant (1)
Gasoline/Diesel Service Station (47)
Hot Mix Asphalt Plant (2)
Industrial Machinery and Equipment (1)
Institutional - school (4}
Landfill (1)
Mine/Quarry (23)
Miscellaneous Commercial/Industrial (3)
Oil and/or Gas Production (4)
Rubber and Miscellaneous Plastics Products (3)
Secondary Metal Processing (1)
Site Remediation Activity (2)
Surface Coating (2)
Textile Mill (1)
Wastewater Treatment (1)
7-3
-------
Figure 7-3. Battlement Mesa, Colorado (BMCO) Monitoring Site
-------
Figure 7-4. Silt, Colorado (BRCO) Monitoring Site
-------
Figure 7-5. Parachute, Colorado (PACO) Monitoring Site
-------
Figure 7-6. Rifle, Colorado (RICO) Monitoring Site
-------
Figure 7-7. NEI Point Sources Located Within 10 Miles of BMCO, BRCO, PACO, and
RICO
i08-i5T>-w 1Q8-10WV ios'5T)-w
tOB'IO'O'W K>B 5'0"W
107'55'G-W 107-50'CTW t07r'45'0'W 107^0BlrV 1Q7"35'G'W 107'30'0'W 107'25'0"W
Note Due to facility density and collocation, Ihe total facilities
displayed may not represent all facilities within the area of interest.
Legend
ฉ BMCO UATMP site jฃ PACO UATMP site
ฎ BRCO UATMP site 5 RICO UATMP site
10 mile radius
J County boundary
Source Category Group (NO. Of Facilities) *
-f Aircraft Operations (7)
* Building Construction (1)
B Bulk Terminals/Bulk Plants (1)
Concrete Batch Plant (1)
ffi Dry Cleaning (1)
* Electricity Generation via Combustion (1)
'A
Gasoline/Diesel Service Station (17)
Hot Mix Asphalt Plant (1)
Landfill (1)
Mine/Quarry (12)
Miscellaneous Commercial/Industrial (2)
Oil and/or Gas Production (920)
Pipeline Compressor Station (8)
7-8
-------
Table 7-1. Geographical Information for the Colorado Monitoring Sites
Site
Code
GPCO
BMCO
BRCO
PACO
RICO
AQS Code
08-077-0017
08-077-0018
None
08-045-0009
08-045-0005
08-045-0007
Location
Grand
Junction
Battlement
Mesa
Silt
Parachute
Rifle
County
Mesa
Garfield
Garfield
Garfield
Garfield
Micro- or
Metropolitan
Statistical Area
Grand Junction,
CO MSA
Not in an MSA
Not in an MSA
Not in an MSA
Not in an MSA
Latitude
and
Longitude
39.064289,
-108.56155
39.4399898,
-108.029769
39.487755,
-107.659685
39.453654,
-108.053259
39.531813,
-107.782298
Land Use
Commercial
Residential
Agricultural
Residential
Commercial
Location
Setting
Urban/City
Center
Rural
Rural
Urban/City
Center
Urban/City
Center
Additional Ambient Monitoring Information1
Meteorological parameters, CO, PM10, PM10
Speciation, PM2 5, and PM2 5 Speciation.
No AQS entry.
None.
PMio, PM10 Speciation.
PMio, PM10 Speciation.
:Data for additional pollutants are reported to AQS for these sites (EPA,
BOLD ITALICS = EPA-designaled NATTS Site
2012c); however, these data are not generated by ERG and are therefore not included in this report.
-------
The GPCO monitoring site is comprised of two locations. The first location is a small
1-story shelter that houses the VOC and carbonyl compound samplers, with the PAH sampler
located just outside the shelter. The second location, which is on the roof of an adjacent 2-story
building, is comprised of the hexavalent chromium samplers. As a result, two AQS codes are
provided in Table 7-1. Figure 7-1 shows that the area surrounding GPCO is of mixed usage, with
commercial businesses to the west, northwest, and north; residential areas to the northeast and
east; and industrial areas to the southeast, south, and southwest. This site's location is next to one
of the major east-west roads in Grand Junction (1-70 Business). A railroad runs east-west to the
south of the GPCO monitoring site, and merges with another railroad to the southwest of the site.
As Figure 7-2 shows, GPCO is located within 10 miles of numerous emissions sources. Many of
the sources are located along a diagonal line running roughly northwest to southeast along
Highways 6 and 50 and Business-70. Many of the point sources near GPCO fall into the
gasoline/diesel service station and mine/quarry source categories. The sources closest to GPCO
are a bulk terminal/bulk plant, an automobile/truck manufacturer, and a gasoline/diesel service
station.
The BMCO monitoring site is located in Battlement Mesa, a rural community located to
the southeast of Parachute. The monitoring site is located on the roof of the Grand Valley Fire
Protection District facility, near the intersection of Stone Quarry Road and West Battlement
Parkway, as shown in Figure 7-3. The site is surrounded primarily by residential subdivisions. A
cemetery is located to the south of the site and a church is located to the east.
The BRCO monitoring site is located on Bell/Melton Ranch, off Owens Drive,
approximately 4 miles south of the town of Silt. The site is both rural and agricultural in nature.
As shown in Figure 7-4, the closest major roadway is County Road 331, Dry Hollow Road.
PACO is located on the roof of the old Parachute High School building, which is
presently operating as a day care facility. This location is in the center of the town of Parachute,
as shown in Figure 7-5. The surrounding area is considered residential. Interstate-70 is less than
a quarter of a mile from the monitoring site.
7-10
-------
RICO is located on the roof of the Henry Annex Building in downtown Rifle. This
location is near the crossroads of several major roadways through town, as shown in Figure 7-6.
Highway 13 and US-6 intersect just south of the site and 1-70 is just over a half-mile south of the
monitoring site across the Colorado River. The surrounding area is considered commercial.
The four Garfield County sites are located along a line running roughly east-west and
spanning approximately 20 miles; hence, they are shown together in Figure 7-7. There are more
than 900 petroleum or natural gas wells (collectively shown as the oil and/or gas production
source category) within 10 miles of these sites. One reason Garfield County is conducting air
monitoring is to characterize the effects these wells may have on the surrounding areas (GCPH,
2010).
Table 7-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Colorado monitoring sites. Table 7-2 includes county-level
population and vehicle registration information. Table 7-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 7-2 also
contains traffic volume information for each site. Finally, Table 7-2 presents the county-level
daily VMT for Mesa and Garfield Counties. Note that the VMT presented is for state highways
only, which differs from the VMT presented in this table in other state sections.
Observations from Table 7-2 include the following:
Mesa County's population and vehicle ownership are considerably higher than those
for Garfield County. This is also true for 10-mile population and vehicle ownership.
However, both counties rank in the bottom-third compared to other counties with
NMP sites.
The vehicle-per-person ratios for the Colorado sites are among the highest for all
NMP sites, with the Garfield County sites' ranking second behind only UCSD, and
GPCO ranking fourth.
The traffic volumes near PACO, RICO, and GPCO are considerably higher than the
traffic volumes near the other Colorado monitoring sites. The lowest traffic volume
7-11
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among all NMP sites is for BRCO. The traffic estimate provided for GPCO is based
on Business-70 near 7th Street; from South Battlement Parkway for BMCO; from the
junction of County Roads 331 and 326 for BRCO; from 1-70 near exit 75 for PACO;
and from Highway 13 between Highway 6 and 1-70 for RICO.
While the Mesa and Garfield County VMTs are fairly similar to each other, they are
also among the lowest for counties with NMP sites, where VMT data were available.
However, the county-level VMT available from the Colorado DOT is for state
highways only.
Table 7-2. Population, Motor Vehicle, and Traffic Information for the Colorado
Monitoring Sites
Site
GPCO
BMCO
BRCO
PACO
RICO
Estimated
County
Population1
147,083
56,270
County-level
Vehicle
Registration2
178,425
72,957
Vehicles per
Person
(Registration:
Population)
1.21
1.30
Population
within 10
miles3
120,030
5,941
25,466
5,941
18,148
Estimated
10-mile
Vehicle
Ownership
145,607
7,703
33,018
7,703
23,530
Annual
Average
Daily
Traffic4
11,000
2,527
150
16,000
17,000
County-level
Daily VMT5
2,031,327
1,901,434
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2010 data from the Colorado DOR (CO DOR, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2002 data for BMCO and BRCO from Garfield County (GCRBD, 2002) and 2011 data for GPCO,
PACO, and RICO from the Colorado DOT (CO DOT, 201 la)
5County-level VMT reflects 2011 data for state highways only from the Colorado DOT (CO DOT, 201 Ib)
BOLD ITALICS = EPA-designaled NATTS Site
7.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Colorado on sample days, as well as over the course of the year.
7.2.1 Climate Summary
Grand Junction is located in a mountain valley on the west side of the Rockies. The
valley location of the city helps protect it from dramatic weather changes. The area tends to be
fairly dry and winds tend to flow out of the east-southeast on average, due to the valley breeze
effect (Bair, 1992). Valley breezes occur as the sun heats up the side of a mountain; the warm air
rises, creating a current that will move up the valley walls (Boubel, et al., 1994).
The towns of Battlement Mesa, Parachute, Rifle, and Silt are located to the northeast of
Grand Junction, across the county line and along the 1-70 corridor. These towns are located along
7-12
-------
a river valley running north of the Grand Mesa. Similar to Grand Junction, these towns are
shielded from drastic changes in weather by the surrounding terrain and tend to experience fairly
dry conditions for most of the year. Wind patterns in these towns are affected by the high
canyons, the Colorado River, and valley breezes (GCPH, 2010 and WRCC, 2013).
7.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather stations nearest these sites were
retrieved for 2011 (NCDC, 2011). The weather station nearest GPCO is located at Walker Field
Airport (WBAN 23066); the closest weather station to the four Garfield County sites is located at
Garfield County Regional Airport (WBAN 03016). Additional information about these weather
stations, such as the distance between the sites and the weather stations, is provided in Table 7-3.
These data were used to determine how meteorological conditions on sample days vary from
conditions experienced throughout the year.
Table 7-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 7-3 is the
95 percent confidence interval for each parameter. As shown in Table 7-3, average
meteorological conditions on sample days near GPCO were representative of average weather
conditions throughout the year. Temperatures on sample days near the Garfield County sites
appear slightly cooler than over the course of the year. This may be attributable to a few missed
sample days in May and September for each site.
7-13
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Table 7-3. Average Meteorological Conditions near the Colorado Monitoring Sites
Closest NWS
Station (WBAN
and Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
<ฐF)
Average
Dew Point
Temperature
<ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Grand Junction, Colorado - GPCO
Walker Field
Airport
23066
(39.13, -108.54)
4.96
miles
22ฐ
(NNE)
Sample
Day
2011
63.8
ฑ5.2
64.5
ฑ2.2
51.5
ฑ4.8
52.3
ฑ2.0
28.2
ฑ3.5
28.5
ฑ1.4
40.5
ฑ3.4
40.9
ฑ1.4
48.9
ฑ4.6
47.7
ฑ1.9
1014.7
ฑ2.2
1014.9
ฑ0.9
6.3
ฑ0.7
6.2
ฑ0.3
Battlement Mesa, Colorado - BMCO
Garfield Co.
Regional Airport
03016
(39.53, -107.73)
16.41
miles
76ฐ
(ENE)
Sample
Day
2011
59.4
ฑ5.6
61.4
ฑ2.2
45.5
ฑ5.1
47.2
ฑ1.9
27.3
ฑ4.2
28.1
ฑ1.4
37.2
ฑ4.0
38.2
ฑ1.5
56.6
ฑ4.3
55.2
ฑ1.7
1016.4
ฑ2.6
1016.7
ฑ0.9
5.1
ฑ0.8
4.5
ฑ0.3
Silt, Colorado - BRCO
Garfield Co.
Regional Airport
03016
(39.53, -107.73)
4.23
miles
316ฐ
(NW)
Sample
Day
2011
59.5
ฑ5.8
61.4
ฑ2.2
45.3
ฑ5.3
47.2
ฑ1.9
26.6
ฑ4.2
28.1
ฑ1.4
36.7
ฑ4.2
38.2
ฑ1.5
55.9
ฑ4.3
55.2
ฑ 1.7
1016.2
ฑ2.7
1016.7
ฑ0.9
5.1
ฑ0.8
4.5
ฑ0.3
Parachute, Colorado - PACO
Garfield Co.
Regional Airport
03016
(39.53, -107.73)
17.22
miles
81ฐ
(E)
Sample
Day
2011
59.4
ฑ5.6
61.4
ฑ2.2
45.5
ฑ5.1
47.2
ฑ1.9
27.3
ฑ4.2
28.1
ฑ1.4
37.1
ฑ4.0
38.2
ฑ 1.5
56.8
ฑ4.3
55.2
ฑ1.7
1016.5
ฑ2.6
1016.7
ฑ0.9
5.0
ฑ0.8
4.5
ฑ0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Table 7-3. Average Meteorological Conditions near the Colorado Monitoring Sites (Continued)
Closest NWS
Station (WBAN
and Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
<ฐF)
Average
Dew Point
Temperature
<ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Rifle, Colorado - RICO
Garfield Co.
Regional Airport
03016
(39.53, -107.73)
2.89
miles
105ฐ
(ESE)
Sample
Day
2011
59.8
ฑ5.7
61.4
ฑ2.2
45.7
ฑ5.2
47.2
ฑ1.9
26.9
ฑ4.0
28.1
ฑ1.4
37.1
ฑ4.0
38.2
ฑ1.5
55.7
ฑ4.3
55.2
ฑ1.7
1016.3
ฑ2.6
1016.7
ฑ0.9
5.2
ฑ0.8
4.5
ฑ0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
7.2.3 Back Trajectory Analysis
Figure 7-8 is the composite back trajectory map for days on which samples were
collected at the GPCO monitoring site in 2011. Included in Figure 7-8 are four back trajectories
per sample day. Figure 7-9 is the corresponding cluster analysis. Similarly, Figures 7-10 through
7-17 are the composite back trajectory maps and corresponding cluster analyses for the Garfield
County monitoring sites. An in-depth description of these maps and how they were generated is
presented in Section 3.5.2.1. For the composite maps, each line represents the 24-hour trajectory
along which a parcel of air traveled toward the monitoring site on a given sample day and time,
based on an initial height of 50 meters AGL. For the cluster analyses, each line corresponds to a
trajectory representative of a given cluster of back trajectories. Each concentric circle around the
sites in Figures 7-8 through 7-17 represents 100 miles.
Observations for GPCO from Figures 7-8 and 7-9 include the following:
The 24-hour air shed domain for GPCO is one of the smallest in size, based on
average back trajectory length, compared to other NMP monitoring sites. The farthest
away a back trajectory originated was over southwest Arizona, or just greater than
450 miles away. However, most trajectories (88 percent) originated within 300 miles
of GPCO and the average trajectory length was approximately 169 miles.
Back trajectories originated from a variety of directions at GPCO, although a large
cluster of trajectories originated to the southwest of GPCO and the majority of the
trajectories had a westerly component.
The cluster analysis shows that back trajectories frequently originated from the
southwest, accounting for roughly 37 percent of back trajectories. Another 27 percent
of trajectories originated from the northwest and west of GPCO. Shorter back
trajectories originating over southeast Utah and southwest Colorado are represented
by the short cluster labeled 24 percent and originating to the south of GPCO. The
cluster originating to the east of GPCO represents back trajectories originating from
the northeast, east, and southeast of the site (12 percent). Thus, air moving towards
GPCO is generally originating in Colorado, Utah, and Arizona.
7-16
-------
Figure 7-8. 2011 Composite Back Trajectory Map for GPCO
Figure 7-9. Back Trajectory Cluster Map for GPCO
7-17
-------
Figure 7-10. 2011 Composite Back Trajectory Map for BMCO
Figure 7-11. Back Trajectory Cluster Map for BMCO
7-18
-------
Figure 7-12. 2011 Composite Back Trajectory Map for BRCO
Figure 7-13. Back Trajectory Cluster Map for BRCO
7-19
-------
Figure 7-14. 2011 Composite Back Trajectory Map for PACO
Figure 7-15. Back Trajectory Cluster Map for PACO
7-20
-------
Figure 7-16. 2011 Composite Back Trajectory Map for RICO
Figure 7-17. Back Trajectory Cluster Map for RICO
7-21
-------
Observations from Figures 7-10 through 7-17 for the Garfield County sites include the
following:
The composite back trajectory maps for the Garfield County sites resemble the one
for GPCO. This is expected, given the sites' close proximity to GPCO (and to each
other).
The 24-hour air shed domains for the Garfield County sites were similar in size to
GPCO, with the average trajectory length ranging from 171 miles for PACO to
181 miles for BRCO. The longest trajectories for these sites originated over central
Arizona. For each Garfield County site, approximately 85 percent of back trajectories
originated within 300 miles of the site.
The cluster maps for the Garfield County sites resemble the cluster map for GPCO,
with most of the trajectories having a southwesterly or northwesterly component.
7.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations at the Walker Field Airport (for
GPCO) and Garfield County Regional Airport (for BMCO, BRCO, PACO, and RICO) were
uploaded into a wind rose software program to produce customized wind roses, as described in
Section 3.5.2.2. A wind rose shows the frequency of wind directions using "petals" positioned
around a 16-point compass, and uses different colors to represent wind speeds.
Figure 7-18 presents a map showing the distance between the NWS station and GPCO,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 7-18 also presents three different wind roses for the
GPCO monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figures 7-19 through 7-22 present the distance maps and
wind roses for the four Garfield County sites.
7-22
-------
Figure 7-18. Wind Roses for the Walker Field Airport Weather Station near GPCO
Distance between GPCO and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
Calms: 17.39%
7-23
-------
Figure 7-19. Wind Roses for the Garfield County Regional Airport near BMCO
Distance between BMCO and NWS Station
2001-2010 Historical Wind Rose
WEST;
2011 Wind Rose
Sample Day Wind Rose
7-24
-------
Figure 7-20. Wind Roses for the Garfield County Regional Airport near BRCO
Distance between BRCO and NWS Station
2001-2010 Historical Wind Rose
r
N
+
WEST;
2011 Wind Rose
Sample Day Wind Rose
7-25
-------
Figure 7-21. Wind Roses for the Garfield County Regional Airport near PACO
Distance between PACO and NWS Station
2001-2010 Historical Wind Rose
WEST
2011 Wind Rose
Sample Day Wind Rose
7-26
-------
Figure 7-22. Wind Roses for the Garfield County Regional Airport near RICO
Distance between RICO and NWS Station
2001-2010 Historical Wind Rose
N
+
WEST;
2011 Wind Rose
Sample Day Wind Rose
Calms: 36.76%
7-27
-------
Observations from Figure 7-18 for GPCO include the following:
The Walker Field Airport weather station is located approximately 5 miles north-
northeast of GPCO. Most of the city of Grand Junction lies between the site and the
weather station.
The historical wind rose shows that easterly, east-southeasterly, and southeasterly
winds were prevalent near GPCO. Calm winds (< 2 knots) were observed for less
than 15 percent of the hourly wind measurements.
The 2011 wind rose exhibits similar wind patterns as the historical wind rose. Further,
the sample day wind patterns also resemble the historical and full-year wind patterns,
indicating that wind conditions on sample days were representative of those
experienced over the entire year and historically.
Observations from Figures 7-19 through 7-22 for the Garfield County sites include the
following:
The NWS weather station at Garfield County Regional Airport is the closest weather
station to all four monitoring sites in Garfield County. The weather station is located
just east of Rifle. The distances from the weather station to the sites varies from less
than 3 miles (RICO) to just over 17 miles (PACO).
The historical and 2011 wind roses for the Garfield County sites are identical to each
other. This is because the wind observations come from the same NWS weather
station for all four sites.
The historical wind roses show that calm winds were prevalent near the monitoring
sites, representing one-third of wind observations. Westerly and southerly winds were
also common.
Calm winds were observed for greater than one third of the wind observations in
2011. The 2011 wind roses exhibit a higher percentage of westerly winds and a
significantly lower percentage of southerly and south-southwesterly winds than the
historical wind rose.
The sample day wind patterns for each site resemble the full-year wind patterns, but
with a higher percentage of northwesterly winds. This resemblance indicates that
conditions on sample days were representative of those experienced over the entire
year.
7-28
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7.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Colorado monitoring sites in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
For each site, each pollutant's preprocessed daily measurement was compared to its associated
risk screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by each monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 7-4 presents the results of the preliminary risk-based screening process for each
Colorado monitoring site. The pollutants that failed at least one screen and contributed to
95 percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. GPCO sampled for
VOCs, carbonyl compounds, PAHs, and hexavalent chromium; the Garfield County sites
sampled for SNMOCs and carbonyl compounds only.
Table 7-4. Risk-Based Screening Results for the Colorado Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Grand Junction, Colorado - GPCO
Naphthalene
Acet aldehyde
Benzene
Formaldehyde
Carbon Tetrachloride
1,3-Butadiene
Ethylbenzene
Acenaphthene
Acrylonitrile
1 ,2-Dichloroethane
Fluorene
ฃ>-Dichlorobenzene
Hexachloro- 1 , 3 -butadiene
Benzo(a)pyrene
0.029
0.45
0.13
0.077
0.17
0.03
0.4
0.011
0.015
0.038
0.011
0.091
0.045
0.00057
61
60
60
60
58
53
36
21
17
16
11
9
8
7
61
60
60
60
60
53
60
61
17
16
61
32
8
44
100.00
100.00
100.00
100.00
96.67
100.00
60.00
34.43
100.00
100.00
18.03
28.13
100.00
15.91
12.25
12.05
12.05
12.05
11.65
10.64
7.23
4.22
3.41
3.21
2.21
1.81
1.61
1.41
12.25
24.30
36.35
48.39
60.04
70.68
77.91
82.13
85.54
88.76
90.96
92.77
94.38
95.78
7-29
-------
Table 7-4. Risk-Based Screening Results for the Colorado Monitoring Sites (Continued)
Pollutant
1 , 1 ,2,2-Tetrachloroethane
Trichloroethylene
1 ,2-Dibromoethane
Dichloromethane
Acenaphthylene
Hexavalent Chromium
Propionaldehyde
1 , 1 ,2-Trichloroethane
Xylenes
Screening
Value
(Ug/m3)
0.017
0.2
0.0017
7.7
0.011
0.000083
0.8
0.0625
10
Total
#of
Failed
Screens
7
4
3
2
1
1
1
1
1
498
#of
Measured
Detections
7
22
3
60
41
42
60
1
60
949
%of
Screens
Failed
100.00
18.18
100.00
3.33
2.44
2.38
1.67
100.00
1.67
52.48
% of Total
Failures
1.41
0.80
0.60
0.40
0.20
0.20
0.20
0.20
0.20
Cumulative
%
Contribution
97.19
97.99
98.59
99.00
99.20
99.40
99.60
99.80
100.00
Battlement Mesa, Colorado - BMCO
Benzene
Formaldehyde
Acet aldehyde
Ethylbenzene
1,3-Butadiene
0.13
0.077
0.45
0.4
0.03
Total
51
20
14
9
8
102
51
20
20
51
8
150
100.00
100.00
70.00
17.65
100.00
68.00
50.00
19.61
13.73
8.82
7.84
50.00
69.61
83.33
92.16
100.00
Silt, Colorado - BRCO
Benzene
1,3-Butadiene
Formaldehyde
Acet aldehyde
0.13
0.03
0.077
0.45
Total
53
6
6
5
70
53
7
6
6
72
100.00
85.71
100.00
83.33
97.22
75.71
8.57
8.57
7.14
75.71
84.29
92.86
100.00
Parachute, Colorado - PACO
Benzene
1,3-Butadiene
Formaldehyde
Acet aldehyde
Ethylbenzene
0.13
0.03
0.077
0.45
0.4
Total
52
21
21
19
12
125
52
22
21
21
53
169
100.00
95.45
100.00
90.48
22.64
73.96
41.60
16.80
16.80
15.20
9.60
41.60
58.40
75.20
90.40
100.00
Rifle, Colorado - RICO
Benzene
1,3-Butadiene
Acet aldehyde
Formaldehyde
Ethylbenzene
0.13
0.03
0.45
0.077
0.4
Total
51
42
17
17
15
142
51
42
17
17
53
180
100.00
100.00
100.00
100.00
28.30
78.89
35.92
29.58
11.97
11.97
10.56
35.92
65.49
77.46
89.44
100.00
7-30
-------
Observations from Table 7-4 include the following:
Twenty-three pollutants failed at least one screen for GPCO, of which eight are
NATTS MQO Core Analytes.
Fourteen pollutants were initially identified as pollutants of interest for GPCO based
on the risk-based screening process, of which seven are NATTS MQO Core Analytes.
Trichloroethylene and hexavalent chromium were added to GPCO's pollutants of
interest because they are NATTS MQO Core Analytes, even though they did not
contribute to 95 percent of GPCO's total failed screens. Three additional NATTS
MQO Core Analytes were also added to GPCO's pollutants of interest even though
their concentrations did not fail any screens: chloroform, tetrachloroethylene, and
vinyl chloride. These three pollutants are not shown in Table 7-4 but are shown in
subsequent tables in the sections that follow.
The number of pollutants failing screens for the Garfield County sites range from four
to five. Four pollutants (benzene, 1,3-butadiene, formaldehyde, and acetaldehyde)
failed screens for each Garfield County site. These four pollutants were identified as
pollutants of interest for all four sites. Ethylbenzene also failed screens for three of
the four Garfield County sites (BRCO being the exception), and was identified as a
pollutant of interest for BMCO, PACO, and RICO.
Note that carbonyl compound samples were collected on a l-in-12 day sampling
schedule at the Garfield County sites, while SNMOCs were collected on a l-in-6 day
sampling schedule; thus, the number of carbonyl compounds samples collected at
these sites were often less than half the number of SNMOC samples.
Benzene and formaldehyde failed 100 percent of screens for all five Colorado sites.
7.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Colorado monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Colorado monitoring sites, where the data meet the
applicable criteria. Concentration averages for select pollutants are also presented graphically for
the sites to illustrate how the sites' concentrations compare to the program-level averages, as
presented in Section 4.1. In addition, concentration averages for select pollutants are presented
from previous years of sampling in order to characterize concentration trends at the sites.
Additional site-specific statistical summaries for the five Colorado sites are provided in
Appendices J through M and Appendix O.
7-31
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7.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Colorado site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Colorado
monitoring sites are presented in Table 7-5, where applicable. Note that concentrations of the
PAHs and hexavalent chromium for GPCO are presented in ng/m3 for ease of viewing. Also note
that if a pollutant was not detected in a given calendar quarter, the quarterly average simply
reflects "0" because only zeros substituted for non-detects were factored into the quarterly
average concentration.
7-32
-------
Table 7-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Colorado Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Grand Junction, Colorado - GPCO
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Hexachloro- 1 ,3 -butadiene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Acenaphthene3
Benzo(a)pyrenea
Fluorene3
Hexavalent Chromium3
Naphthalene3
60/60
17/60
60/60
53/60
60/60
42/60
32/60
16/60
60/60
60/60
8/60
7/60
53/60
22/60
6/60
61/61
44/61
61/61
42/59
61/61
1.81
ฑ0.34
0.01
ฑ0.03
1.32
ฑ0.29
0.15
ฑ0.04
0.44
ฑ0.08
0.07
ฑ0.02
0.02
ฑ0.02
0.01
ฑ0.02
0.46
ฑ0.13
2.84
ฑ0.37
0.02
ฑ0.02
0.01
ฑ0.01
0.26
ฑ0.07
0.04
ฑ0.02
<0.01
ฑ<0.01
15.27
ฑ6.69
0.23
ฑ0.11
7.65
ฑ2.43
0.01
ฑ0.01
240.29
ฑ 96.22
1.47
ฑ0.24
0.15
ฑ0.11
1.49
ฑ1.35
0.07
ฑ0.03
0.50
ฑ0.08
0.08
ฑ0.03
0.01
ฑ0.02
0.04
ฑ0.03
0.34
ฑ0.06
2.53
ฑ0.27
0.01
ฑ0.02
0.01
ฑ0.01
0.18
ฑ0.08
0.02
ฑ0.03
<0.01
ฑ<0.01
9.75
ฑ4.24
0.03
ฑ0.02
7.65
ฑ2.26
0.01
ฑ<0.01
106.40
ฑ 36.96
3.12
ฑ0.45
0.06
ฑ0.04
0.90
ฑ0.14
0.09
ฑ0.02
0.62
ฑ0.08
0.07
ฑ0.04
0.06
ฑ0.02
0.02
ฑ0.02
0.69
ฑ0.18
2.84
ฑ0.37
0.02
ฑ0.02
0.02
ฑ0.02
0.15
ฑ0.05
0.04
ฑ0.04
<0.01
ฑ<0.01
12.07
ฑ2.27
0.06
ฑ0.07
9.39
ฑ1.47
0.01
ฑ<0.01
121.08
ฑ 19.58
3.36
ฑ0.62
0.01
ฑ0.02
1.69
ฑ0.40
0.23
ฑ0.06
0.57
ฑ0.06
0.11
ฑ0.03
0.07
ฑ0.02
0.04
ฑ0.03
1.00
ฑ0.33
2.74
ฑ0.41
0.01
ฑ0.01
O.01
ฑ0.01
0.45
ฑ0.15
0.07
ฑ0.06
O.01
ฑO.01
4.95
ฑ1.72
0.49
ฑ0.26
5.90
ฑ1.66
0.03
ฑ0.02
156.63
ฑ 47.25
2.43
ฑ0.29
0.06
ฑ0.03
1.34
ฑ0.35
0.13
ฑ0.02
0.53
ฑ0.04
0.08
ฑ0.02
0.04
ฑ0.01
0.03
ฑ0.01
0.62
ฑ0.11
2.74
ฑ0.17
0.01
ฑ0.01
0.01
ฑ0.01
0.26
ฑ0.05
0.04
ฑ0.02
O.01
ฑO.01
10.54
ฑ2.17
0.20
ฑ0.08
7.68
ฑ0.98
0.02
ฑ0.01
155.52
ฑ29.71
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line for GPCO are presented in ng/m3
for ease of viewing.
7-33
-------
Table 7-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Colorado Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Battlement Mesa, Colorado - BMCO
Acetaldehyde
Benzene
1,3 -Butadiene
Ethylbenzene
Formaldehyde
20/20
51/51
8/51
51/51
20/20
0.71
ฑ0.29
1.37
ฑ0.36
0.02
ฑ0.03
0.24
ฑ0.04
1.42
ฑ0.57
NA
NA
NA
NA
NA
NA
2.65
ฑ1.04
0
0.65
ฑ0.36
NA
NA
1.22
ฑ0.36
0.05
ฑ0.03
0.28
ฑ0.14
NA
NA
NA
NA
NA
NA
Silt, Colorado - BRCO
Acetaldehyde
Benzene
1,3 -Butadiene
Formaldehyde
6/6
53/54
7/54
6/6
NA
1.06
ฑ0.29
0.02
ฑ0.02
NA
NA
0.48
ฑ0.12
0
NA
NA
NA
NA
NA
NA
0.85
ฑ0.15
0.02
ฑ0.02
NA
NA
0.86
ฑ0.13
0.01
ฑ0.01
NA
Parachute, Colorado - PACO
Acetaldehyde
Benzene
1,3 -Butadiene
Ethylbenzene
Formaldehyde
21/21
52/53
22/53
53/53
21/21
0.85
ฑ0.33
1.61
ฑ0.47
0.13
ฑ0.06
0.25
ฑ0.07
1.41
ฑ0.33
NA
NA
NA
NA
NA
NA
1.61
ฑ0.46
0
0.59
ฑ0.27
NA
1.07
ฑ0.29
1.56
ฑ0.35
0.11
ฑ0.05
0.27
ฑ0.06
1.83
ฑ0.39
NA
1.45
ฑ0.21
0.07
ฑ0.03
0.32
ฑ0.07
NA
Rifle, Colorado - RICO
Acetaldehyde
Benzene
1,3 -Butadiene
Ethylbenzene
Formaldehyde
17/17
51/53
42/53
53/53
17/17
1.47
ฑ0.58
1.48
ฑ0.36
0.27
ฑ0.09
0.34
ฑ0.06
1.99
ฑ0.84
NA
0.64
ฑ0.14
0.09
ฑ0.04
0.22
ฑ0.03
NA
NA
NA
NA
NA
NA
NA
1.75
ฑ0.32
0.28
ฑ0.08
0.47
ฑ0.11
NA
NA
1.27
ฑ0.18
0.18
ฑ0.04
0.35
ฑ0.04
NA
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line for GPCO are presented in ng/m3
for ease of viewing.
7-34
-------
Observations for GPCO from Table 7-5 include the following:
The pollutants with the highest annual average concentrations by mass are
formaldehyde (2.74 ฑ 0.17 |ig/m3), acetaldehyde (2.43 ฑ 0.29 |ig/m3), and benzene
(1.34 ฑ 0.35 |ig/m3). These are also the only pollutants with annual average
concentrations greater than 1 |ig/m3.
The confidence intervals associated with the quarterly average concentrations of
acrylonitrile are relatively high and in some case greater than the quarterly averages
themselves. This pollutant was detected 17 times in 2011 and its measurements
ranged from 0.0739 |ig/m3to 0.757 |ig/m3. Thus, a large number of zeros (43) were
substituted into the calculations, leading to the appearance of a higher level of
variability within the average concentrations, which is reflected in the confidence
intervals. Nine of the 17 measured detections were measured during the second
quarter. The minimum and maximum acrylonitrile concentrations were measured
during this quarter.
Acetaldehyde concentrations were highest during third and fourth quarters of the
year. This trend is not reflected in the formaldehyde concentrations.
Benzene's second quarter confidence interval is nearly as great as the quarterly
average concentration, indicating the likely influence of outliers. The maximum
concentration of benzene was measured at GPCO on June 8, 2011 (10.6 |ig/m3). This
concentration is more than twice the next highest measurement (3.55 |ig/m3 measured
on November 29, 2011) and more than seven times the next highest concentration
measured in that quarter (1.49 |ig/m3 measured on April 27, 2011). The June 8th
concentration is also the fourth highest benzene concentration measured across the
program.
For many VOCs, the fourth quarter averages were greater than the other quarterly
averages, particularly for 1,3-butadiene, ethylbenzene, and tetrachloroethylene.
However, the differences across the averages are not statistically significant.
The first quarter average concentration of naphthalene is the highest of the quarterly
averages and has a relatively large confidence interval associated with it. A review of
the data shows that concentrations of naphthalene range from 38.1 ng/m3 to
650 ng/m3, with three of the highest measurements of naphthalene (those greater than
400 ng/m3) measured in January and February of 2011. GPCO has three of six highest
naphthalene concentrations measured across the program
Average benzo(a)pyrene concentrations for the first and fourth quarters of 2011 are
significantly higher than the average concentrations for the other two quarters. A
review of the data shows that 22 of the 25 concentrations of this pollutant greater than
0.01 ng/m3 were measured during the first and fourth quarters of 2011. Conversely,
14 of the 16 non-detects were measured during the second and third quarters of 2011.
Three measurements of benzo(a)pyrene greater than 1 ng/m3 were measured during a
1-month period between November and December 2011; these measurements account
for three of the seven measurements of benzo(a)pyrene greater than 1 ng/m3 measured
across the program for all NMP sites sampling PAHs.
7-35
-------
Observations for the Garfield County sites from Table 7-5 include the following:
Of the SNMOCs, benzene has the highest annual average concentration by mass for
each of the Garfield County sites. Annual average concentrations of benzene ranged
from 0.86 ฑ 0.13 |ig/m3 for BRCO to 1.45 ฑ 0.21 |ig/m3 for PACO. While PACO's
benzene concentrations were steady across 2011, the quarterly average concentrations
of benzene for the other sites exhibit more variability.
The annual average concentrations of 1,3-butadiene varied significantly across the
Garfield County sites, ranging from 0.01 ฑ 0.0.1 |ig/m3 for BRCO to
0.18 ฑ 0.04 |ig/m3 for RICO. A comparison of the Garfield County sites shows that
the 10 highest concentrations of 1,3-butadiene were measured at RICO, all of which
were measured during the first and fourth quarters of 2011. Note that this pollutant
was not detected during the second quarter at BRCO nor at BMCO and PACO during
the third quarter of 2011. However, the lack of quarterly averages across all sites and
all quarters makes a seasonal trend difficult to determine.
Annual average concentrations for the carbonyl compound pollutants of interest could
not be calculated for any of the Garfield County sites because these sites did not meet
the quarterly completeness criteria specified above. However, Appendix L provides
the pollutant-specific average concentrations for all valid samples collected over the
entire sample period for each site.
Annual average concentrations for the SNMOC pollutants of interest could not be
calculated for BMCO because the overall method completeness criterion was not met.
Appendix K also provides the pollutant-specific average concentrations for all valid
SNMOC samples collected over the entire sample period.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the Colorado
sites from those tables include the following:
Annual average concentrations for GPCO appear in Tables 4-9 through 4-12 a total of
14 times.
GPCO appears frequently in Table 4-9 for VOCs, although its highest ranking is
fourth (ethylbenzene). PACO's annual average benzene concentration ranked third
among all sites sampling this pollutant, with GPCO and RICO ranking sixth and
seventh, respectively. RICO and GPCO rank fourth and seventh for 1,3-butadiene,
respectively.
GPCO's annual average acetaldehyde concentration ranked sixth highest among
NMP sites sampling carbonyl compounds, as shown in Table 4-10. GPCO's
formaldehyde concentration does not appear in this table (it ranked 12th).
As shown in Table 4-11 for the PAHs, GPCO has the highest annual concentration of
naphthalene and benzo(a)pyrene among all NMP sites sampling PAHs. This site also
7-36
-------
has the fourth highest annual average of acenaphthene and the sixth highest annual
average of fluorene.
7.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzene and 1,3-butadiene
were created for each of the Colorado sites. Note that these box plots are split into separate
figures, one for measurements sampled with Method TO-15 (GPCO) and one for measurements
sampled with the SNMOC method (the Garfield County sites). Box plots for acetaldehyde and
formaldehyde were created for GPCO (the only site for which annual averages for these
pollutants could be calculated). Box plots were also created for benzo(a)pyrene, hexavalent
chromium, and naphthalene for GPCO. Figures 7-23 through 7-29 overlay the sites' minimum,
annual average, and maximum concentrations onto the program-level minimum, first quartile,
median, average, third quartile, and maximum concentrations, as described in Section 3.5.3.
Figure 7-23. Program vs. Site-Specific Average Acetaldehyde Concentration
6PCC
Concentration (
Program: 1st Quartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site: Site Average Site Minimum/Maximum
Figure 7-24a. Program vs. Site-Specific Average Benzene (Method TO-15) Concentration
GPCO
Program Max Concentration = 23.8 ng/m3
4 5
Concentration (
Program:
Site:
1st Quartile
Site Average
o
2nd Quartile
3rd Quartile
n
4th Quartile Average
n
^ 1 1
Site Minimum/Maximum
7-37
-------
Figure 7-24b. Program vs. Site-Specific Average Benzene (SNMOC) Concentrations
BRCC
3 4
Concentration (mj/mj)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 7-25. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
-o-
0.75 1 1.Z5
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 7-26a. Program vs. Site-Specific Average 1,3-Butadiene (Method TO-15)
Concentration
Program Max Concentration = 9.51
Program:
Site:
IstQuartile
Site Average
0
2ndQuartile
SrdQuartile
n
4thQuartile Average
n
^m i i
Site Minimum/Maximum
7-38
-------
Figure 7-26b. Program vs. Site-Specific Average 1,3-Butadiene (SNMOC) Concentrations
BRCC
Program Max Concentration = 2.35 ug/rna
Program Max Concentration = 2.35 ug/ma
-O
Program Max Concentration = 2.35
0.4 3.5
Concentration (
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 7-27. Program vs. Site-Specific Average Formaldehyde Concentration
IS
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 7-28. Program vs. Site-Specific Average Hexavalent Chromium Concentration
0.15
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
7-39
-------
Figure 7-29. Program vs. Site-Specific Average Naphthalene Concentration
GFCC
^m
^^*
3 50
i Program Max Concentration
100 150 200 250 300 350 400
Concentration (ng/mi)
J
= 779 ng/m3
450 5C
Program
Site:
: IstQuartile
Site Average
O
2ndQuartile 3rd Quartile 4thQuartile Ave
Site Minimum/Maximum
rage
Observations from Figures 7-23 through 7-29 include the following:
Figure 7-23 shows that GPCO's annual average acetaldehyde concentration is
greater than the program-level average concentration and just less than the
program-level third quartile (or 75th percentile). The maximum acetaldehyde
concentration measured at GPCO is less than the maximum concentration
measured across the program.
Figure 7-24a presents the benzene concentrations for GPCO compared to the
benzene concentrations measured across the program for NMP sites sampling
VOCs with Method TO-15; Figure 7-24b presents the annual average benzene
concentrations for the Garfield County sites compared to the benzene
concentrations measured across the program for NMP sites sampling SNMOCs.
The box plots are presented this way to correspond with Tables 4-1 and 4-2 in
Section 4.1, as discussed in Section 3.5.3.
Figure 7-24a is the box plot for benzene for GPCO. The program-level maximum
concentration (23.8 |ig/m3) is not shown directly on the box plot because the scale
of the box plot would be too large to readily observe data points at the lower end
of the concentration range. Thus, the scale has been reduced to 10 |ig/m3. The box
plot shows that the annual average benzene concentration for GPCO is greater
than the program-level average concentration as well as the third quartile for the
program. While the maximum benzene concentration measured at GPCO is less
than the maximum measured across the program, it is greater than the scale on the
graph (10.6 |ig/m3).
The annual average benzene concentrations for PACO and RICO are greater than
the program-level average concentration while the annual average concentration
for BRCO is just less than the program-level average, as shown in Figure 7-24b.
The annual averages for PACO and RICO are also greater than the program-level
third quartile. The maximum benzene concentration measured by sites sampling
SNMOCs was not measured at the Garfield County sites.
Figure 7-25 is the box plot for benzo(a)pyrene for GPCO. Note that the program-
level first quartile for this pollutant is zero and is not visible on this box plot. The
box plot shows that the annual average concentration for GPCO is greater than the
7-40
-------
program-level average concentration as well as the program-level third quartile.
Recall from the previous section that GPCO has the highest annual average
benzo(a)pyrene concentration among all sites sampling PAHs. Figure 7-25 also
shows that while the maximum benzo(a)pyrene concentration measured at GPCO
(1.54 ng/m3) is not the maximum concentration measured across the program
(1.99 ng/m3), it was the second highest. The third highest concentration measured
across the program was also measured at GPCO. Several non-detects of
benzo(a)pyrene were measured at GPCO.
Similar to the box plots for benzene, Figure 7-26a presents the annual average
concentration of 1,3-butadiene for GPCO compared to the 1,3-butadiene
concentrations measured across the program for NMP sites sampling VOCs with
Method TO-15; Figure 7-26b presents the annual average 1,3-butadiene
concentrations for the Garfield County sites compared to the 1,3-butadiene
concentrations measured across the program for NMP sites sampling SNMOCs.
Note that the program-level maximum concentrations are not shown directly on
either box plot as the scale has been reduced to allow for the observation of data
points at the lower end of the concentration range.
Figure 7-26a shows that, similar to benzene, GPCO's annual average
1,3-butadiene concentration is greater than the program-level average
concentration and greater than the third quartile for the program. However, the
maximum concentration measured at GPCO is considerably less than the
maximum concentration measured across the program. A few non-detects of
1,3-butadiene were measured at GPCO.
The first and second quartiles (and median concentration) at the program-level are
zero, and thus, not shown in Figure 7-26b, indicating that at least half of the
1,3-butadiene concentrations measured by sites sampling SNMOCs were
non-detects. Figure 7-26b shows that, of the Garfield County sites for which
annual average concentrations could be calculated, RICO's annual average
1,3-butadiene concentration is the highest and BRCO's annual average the lowest.
This figure also shows that the annual average concentration for BRCO is less
than the program-level average, the annual average concentration for PACO is
similar to the program-level average, and the annual average concentration for
RICO is more than twice the program-level average concentration.
Figure 7-27 shows that GPCO's annual average formaldehyde concentration is
just less than the program-level average concentration. The range of
formaldehyde concentrations measured at GPCO appears rather small, ranging
from 1.65 |ig/m3 to 4.28 |ig/m3. Note that the minimum formaldehyde
concentration measured at GPCO is greater than the program-level first quartile.
7-41
-------
Figure 7-28 is the box plot for hexavalent chromium for GPCO. The figure shows
that the annual average concentration for GPCO is less than both the program-
level average and median concentrations. Although the maximum concentration
measured at GPCO is less than the maximum concentration measured across the
program, GPCO's maximum concentration is the seventh highest measurement of
this pollutant among sites sampling hexavalent chromium. Several non-detects of
hexavalent chromium were measured at GPCO.
Figure 7-29 is the box plot for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 500 ng/m3 to allow for the observation of data points at
the lower end of the concentration range. Figure 7-29 shows that the annual
average naphthalene concentration for GPCO is greater than the program-level
average concentration as well as the program-level third quartile. Recall from the
previous section that GPCO has the highest annual average naphthalene
concentration among all sites sampling PAHs. The maximum naphthalene
concentration measured at GPCO (650 ng/m3) is the second highest measurement
across the program. The minimum concentration of naphthalene measured at
GPCO (38.1 ng/m3) is greater than the program-level first quartile (32.8 ng/m3).
7.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. GPCO has sampled carbonyl compounds and VOCs since 2004 and hexavalent
chromium since 2005. Thus, Figures 7-30 through 7-35 present the annual statistical metrics for
acetaldehyde, benzene, 1,3-butadiene, formaldehyde, and hexavalent chromium for GPCO,
respectively. The statistical metrics presented for assessing trends include the substitution of
zeros for non-detects.
GPCO began sampling PAHs and BRCO, PACO, and RICO began sampling SNMOCs
and carbonyl compounds under the NMP in 2008; because this is fewer than 5 consecutive years
of sampling, the trends analysis was not conducted for the listed pollutants for these methods.
BMCO began sampling SNMOCs and carbonyl compounds under the NMP at the end of 2010;
thus, the trends analysis was not conducted for this site either.
7-42
-------
Figure 7-30. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at GPCO
1
TS ,= .
ge Concentration fi'
j I
C
8
=t
The maximum
concentrationfor |
2004 is 93.0 Hg/m3 |
ซ.
^^m
f
I
2004
T T T
p i Li
E , t i I
|_l tf^
^ -^ --- * -t- '--'
2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile "^--Average
Figure 7-31. Annual Statistical Metrics for Benzene Concentrations
Measured at GPCO
2004 2005 2006 2007 200B 2009 2010
5th Percentile Minimum Median Maximum * 95th Percentile * + ^.. Average
7-43
-------
Figure 7-32. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at GPCO
2004 2005 2006 2007 200S 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile "^--Average
Figure 7-33. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at GPCO
E
B
.&
|
1
a
& s
e 8
1
4
.
The maximum
concentration for
2004 is 40.5 u.g/m.3
rn Jn ^ rh ฑ
I
_ "*" *^ --..
I f
U.J 1 L^
r
k L
2004 2005 2006 2007 200B 2009 2010 2011
Year
5th Percentile Minimum Median Max mum 95th Percentile * + ^.. Average
7-44
-------
Figure 7-34. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at GPCO
r
E
.2
E
ฃ 0.4
I
3
a,
2
- Minimum
- Maximum
9SthPercentile
SthPercentile
Average
Observations from Figure 7-30 for acetaldehyde measurements at GPCO include the
following:
The maximum acetaldehyde concentration was measured during 2004. The maximum
concentrations measured in subsequent time periods were significantly lower. The
two highest acetaldehyde concentrations (93.0 |ig/m3 and 54.9 |ig/m3) were measured
in 2004 and the six highest acetaldehyde concentrations (ranging from 6.35 |ig/m3to
93.0 |ig/m3) were all measured in 2004 and 2005.
After the first two years of sampling, the median and average concentrations fluctuate
only slightly from year to year. The average concentration ranged from 2.00 |ig/m3
for 2010 to 2.90 |ig/m3 for 2009 for the period from 2006 to 2011.
Although difficult to discern in Figure 7-30, the average and median concentrations
differ less than 0.15 |ig/m3 for each year after 2005, indicating relatively little
variability in the central tendency of acetaldehyde concentrations measured over the
periods shown.
7-45
-------
Observations from Figure 7-31 for benzene measurements at GPCO include the
following:
The maximum benzene concentration (10.6 |ig/m3) was measured on June 8, 2011.
Only three additional concentrations greater than 5 |ig/m3 have been measured at
GPCO, two in 2004 and one in 2009.
Even with the maximum concentration, most of the statistical metrics for 2011
decreased from 2010 to 2011.
Although there have been fluctuations, both the average and median concentrations of
benzene have decreased slightly over time.
There have been no non-detects of benzene reported over the period of sampling.
Observations from Figure 7-32 for 1,3-butadiene measurements at GPCO include the
following:
The maximum 1,3-butadiene concentration was measured on December 11, 2004 and
is the only 1,3-butadiene concentration greater than 1 |ig/m3 measured at GPCO.
The average concentrations appear to have a slight decreasing trend; however,
confidence intervals calculated from the individual concentrations show that this
decrease is not statistically significant.
The difference between the average and the median concentrations is at a minimum
for 2011, which can be an indication of decreasing variability in the measurements.
The number of non-detects, and subsequently zeros substituted for non-detects,
decreased from approximately 30 percent in 2004 and 2005, to eight percent in 2006,
to none in 2007, 2008, and 2009. The number of non-detects began to increase
slightly after 2009, up to three percent in 2010 and nearly 12 percent in 2011.
Observations from Figure 7-33 for formaldehyde measurements at GPCO include the
following:
The trends graph for formaldehyde resembles the trends graph for acetaldehyde in
that the maximum formaldehyde concentration was measured in 2004 and is
significantly higher than the maximum concentrations measured in subsequent years.
The three highest concentrations of formaldehyde were measured on the same days as
the three highest acetaldehyde concentrations.
Even with decreasing maximum concentrations, the average formaldehyde
concentrations (as well as several other statistical parameters) have a slight increasing
trend through 2006. Between 2006 and 2009, the average concentration was
approximately 4 |ig/m3. A significant decrease in all of the statistical metrics is shown
for 2010, with little change for 2011.
7-46
-------
The difference between the 5th and 95th percentiles has been decreasing since 2007,
and is at a minimum for 2011, which indicates a smaller range in the majority of the
concentrations measured. The decreasing difference between the median and average
concentrations is a further indicator of the decreasing variability in the formaldehyde
measurements at GPCO.
Observations from Figure 7-34 for hexavalent chromium measurements at GPCO include
the following:
The maximum hexavalent chromium concentration was measured on July 5, 2008
(0.685 ng/m3). Only two additional hexavalent chromium concentrations measured at
GPCO are greater than 0.1 ng/m3, one measured on December 29, 2011 (0.154 ng/m3)
and the other on August 9, 2006 (0.113 ng/m3).
The average concentration of hexavalent chromium for 2008 is being driven by the
outlier measured that year. If that measurement was removed from the calculation,
concentrations of hexavalent chromium would exhibit a steady decreasing trend
between 2006 and 2009, followed by an increasing trend for 2010 and 2011.
Both the minimum concentration and 5th percentile for all years of sampling are zero,
indicating the presence of non-detects. For 2009, the median (or 50th percentile) is
also zero indicating that at least half of the measurements were non-detects. The
percentage of non-detects has ranged from 18 percent in 2006 to 60 percent in 2009.
7.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each Colorado monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
7.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Colorado monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
7-47
-------
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
7.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Colorado sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 7-6, where applicable. Cancer risk approximations
are presented as probabilities while the noncancer hazard approximations are ratios and thus,
unitless values.
Table 7-6. Risk Approximations for the Colorado Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Grand Junction, Colorado - GPCO
Acenaphthene3
Acetaldehyde
Acrylonitrile
Benzene
Benzo(a)pyrenea
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
0.000088
0.0000022
0.000068
0.0000078
0.00176
0.00003
0.000006
0.009
0.002
0.03
_
0.002
0.1
0.098
61/61
60/60
17/60
60/60
44/61
53/60
60/60
42/60
0.01
ฑ<0.01
2.43
ฑ0.29
0.06
ฑ0.03
1.34
ฑ0.35
<0.01
ฑ0.01
0.13
ฑ0.02
0.53
ฑ0.04
0.08
ฑ0.02
0.93
5.35
4.07
10.42
0.35
4.01
3.20
0.27
0.03
0.04
_
0.07
0.01
<0.01
= a Cancer URE or Noncancer RfC is not available.
NA = Not available due to the criteria for calculating an annual average.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 7-5.
7-48
-------
Table 7-6. Risk Approximations for the Colorado Monitoring Sites (Continued)
| Pollutant
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Fluorene3
Formaldehyde
Hexachloro- 1 , 3 -butadiene
Hexavalent Chromium3
Naphthalene3
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Cancer
URE
(Hg/m3)1
0.000011
0.000026
0.0000025
0.000088
0.000013
0.000022
0.012
0.000034
0.000058
0.00000026
0.0000048
0.0000088
Noncancer
RfC
(mg/m3)
0.8
2.4
1
0.0098
0.09
0.0001
0.003
0.04
0.002
0.1
#of
Measured
Detections
vs.
# of Samples
32/60
16/60
60/60
61/61
60/60
8/60
42/59
61/61
7/60
53/60
22/60
6/60
Annual
Average
(Hg/m3)
0.04
ฑ0.01
0.03
ฑ0.01
0.62
ฑ0.11
0.01
ฑ<0.01
2.74
ฑ0.17
0.01
ฑ0.01
0.01
ฑ0.01
0.16
ฑ0.03
0.01
ฑ0.01
0.26
ฑ0.05
0.04
ฑ0.02
O.01
ฑO.01
Cancer Risk
Approximation
(in-a-million)
0.44
0.69
1.54
0.68
35.60
0.32
0.19
5.29
0.56
0.07
0.21
0.02
Noncancer
Hazard
Approximation
(HQ)
O.01
0.01
O.01
0.28
O.01
0.01
0.05
0.01
0.02
O.01
Battlement Mesa, Colorado - BMCO
Acetaldehyde
Benzene
1,3 -Butadiene
Ethylbenzene
Formaldehyde
0.0000022
0.0000078
0.00003
0.0000025
0.000013
0.009
0.03
0.002
1
0.0098
20/20
51/51
8/51
51/51
20/20
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Silt, Colorado - BRCO
Acetaldehyde
Benzene
1,3 -Butadiene
Formaldehyde
0.0000022
0.0000078
0.00003
0.000013
0.009
0.03
0.002
0.0098
6/6
53/54
7/54
6/6
NA
0.86
ฑ0.13
0.01
ฑ0.01
NA
NA
6.71
0.34
NA
NA
0.03
0.01
NA
= a Cancer URE or Noncancer RfC is not available.
NA = Not available due to the criteria for calculating an annual average.
3 For the annual average concentration of this pollutant in ng/m3, refer to Table 7-5.
7-49
-------
Table 7-6. Risk Approximations for the Colorado Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Parachute, Colorado - PACO
Acetaldehyde
Benzene
1,3 -Butadiene
Ethylbenzene
Formaldehyde
0.0000022
0.0000078
0.00003
0.0000025
0.000013
0.009
0.03
0.002
1
0.0098
21/21
52/53
22/53
53/53
21/21
NA
1.45
ฑ0.21
0.07
ฑ0.03
0.32
ฑ0.07
NA
NA
11.27
2.10
0.79
NA
NA
0.05
0.04
0.01
NA
Rifle, Colorado - RICO
Acetaldehyde
Benzene
1,3 -Butadiene
Ethylbenzene
Formaldehyde
0.0000022
0.0000078
0.00003
0.0000025
0.000013
0.009
0.03
0.002
1
0.0098
17/17
51/53
42/53
53/53
17/17
NA
1.27
ฑ0.18
0.18
ฑ0.04
0.35
ฑ0.04
NA
NA
9.93
5.53
0.87
NA
NA
0.04
0.09
0.01
NA
= a Cancer URE or Noncancer RfC is not available.
NA = Not available due to the criteria for calculating an annual average.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 7-5.
Observations for GPCO from Table 7-6 include the following:
Formaldehyde, acetaldehyde, and benzene have the highest annual average
concentrations for GPCO.
Formaldehyde also has the highest cancer risk approximation (35.60 in-a-million) for
this site. Benzene has the second highest cancer risk approximation
(10.42 in-a-million) and acetaldehyde has the third highest cancer risk approximation
(5.35 in-a-million), with naphthalene a close fourth (5.29 in-a-million).
None of the pollutants of interest for GPCO have noncancer hazard approximations
greater than 1.0, indicating no adverse health effects are expected from these
individual pollutants. Formaldehyde has the highest noncancer hazard approximation
(0.28) among the pollutants of interest for GPCO.
7-50
-------
Observations for the Garfield County sites from Table 7-6 include the following:
Benzene's cancer risk approximation is the highest among each site's pollutants of
interest, where risk approximations could be calculated. Benzene's cancer risk
approximations range from 6.71 in-a-million for BRCO to 11.27 in-a-million for
PACO. PACO's benzene cancer risk approximation is the third highest benzene
cancer risk approximation compared to other NMP sites.
None of the noncancer hazard approximations calculated for the Garfield County sites
are greater than 1.0, indicating no adverse health effects are expected from these
individual pollutants. The highest noncancer hazard approximation was calculated for
1,3-butadiene for RICO (0.09).
Annual averages, and thus cancer risk and noncancer hazard approximations, could
not be calculated for acetaldehyde and formaldehyde for any of the Garfield County
sites because the completeness criteria were not met, as discussed in Section 7.4.1.
Annual averages, and thus cancer risk and noncancer hazard approximations, could
not be calculated for the SNMOCs for BMCO due to completeness issues, as
discussed in Section 7.4.1.
7.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 7-7 and 7-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 7-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 7-6. Table 7-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 7-6.
7-51
-------
Table 7-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Colorado Monitoring Sites
to
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Grand Junction, Colorado (Mesa County) - GPCO
Benzene
Formaldehyde
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Tetrachloroethylene
POM, Group 6
140.94
112.12
45.52
41.56
14.18
7.63
6.38
2.02
1.20
0.20
Formaldehyde
Benzene
1,3 -Butadiene
POM, Group 3
Naphthalene
POM, Group 2b
Arsenic, PM
Hexavalent Chromium, PM
Ethylbenzene
Acetaldehyde
1.46E-03
1.10E-03
4.25E-04
3.93E-04
2.59E-04
1.78E-04
1.58E-04
1.37E-04
1.04E-04
l.OOE-04
Formaldehyde
Benzene
Acetaldehyde
Naphthalene
Acrylonitrile
1,3 -Butadiene
Carbon Tetrachloride
Ethylbenzene
Acenaphthene
1 ,2-Dichloroethane
35.60
10.42
5.35
5.29
4.07
4.01
3.20
1.54
0.93
0.69
Battlement Mesa, Colorado (Garfield County) - BMCO
Formaldehyde
Benzene
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
POM, Group 2b
Tetrachloroethylene
Dichloromethane
POM, Group 6
324.22
269.17
79.93
27.66
16.04
6.02
2.69
1.34
0.74
0.32
Formaldehyde
Benzene
POM, Group 3
1,3 -Butadiene
POM, Group 2b
Naphthalene
Acetaldehyde
POM, Group 5a
Ethylbenzene
POM, Group 6
4.21E-03
2.10E-03
8.97E-04
4.81E-04
2.37E-04
2.05E-04
1.76E-04
l.OOE-04
6.92E-05
5.61E-05
-------
Table 7-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Colorado Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations
Based on Annual Average Concentrations
(Site-Specific)
Cancer Risk
Approximation
Pollutant (in-a-million)
Silt, Colorado (Garfield County) - BRCO
Formaldehyde
Benzene
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
POM, Group 2b
Tetrachloroethylene
Dichloromethane
POM, Group 6
324.22
269.17
79.93
27.66
16.04
6.02
2.69
1.34
0.74
0.32
Formaldehyde
Benzene
POM, Group 3
1,3 -Butadiene
POM, Group 2b
Naphthalene
Acetaldehyde
POM, Group 5a
Ethylbenzene
POM, Group 6
4.21E-03
2.10E-03
8.97E-04
4.81E-04
2.37E-04
2.05E-04
1.76E-04
l.OOE-04
6.92E-05
5.61E-05
Benzene 6.71
1,3-Butadiene 0.34
Parachute, Colorado (Garfield County) - PACO
Formaldehyde
Benzene
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
POM, Group 2b
Tetrachloroethylene
Dichloromethane
POM, Group 6
324.22
269.17
79.93
27.66
16.04
6.02
2.69
1.34
0.74
0.32
Formaldehyde
Benzene
POM, Group 3
1,3 -Butadiene
POM, Group 2b
Naphthalene
Acetaldehyde
POM, Group 5a
Ethylbenzene
POM, Group 6
4.21E-03
2.10E-03
8.97E-04
4.81E-04
2.37E-04
2.05E-04
1.76E-04
l.OOE-04
6.92E-05
5.61E-05
Benzene 11.27
1,3-Butadiene 2.10
Ethylbenzene 0.79
-------
Table 7-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Colorado Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Rifle, Colorado (Garfield County) - RICO
Formaldehyde
Benzene
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
POM, Group 2b
Tetrachloroethylene
Dichloromethane
POM, Group 6
324.22
269.17
79.93
27.66
16.04
6.02
2.69
1.34
0.74
0.32
Formaldehyde
Benzene
POM, Group 3
1,3 -Butadiene
POM, Group 2b
Naphthalene
Acetaldehyde
POM, Group 5a
Ethylbenzene
POM, Group 6
4.21E-03
2.10E-03
8.97E-04
4.81E-04
2.37E-04
2.05E-04
1.76E-04
l.OOE-04
6.92E-05
5.61E-05
Benzene
1,3 -Butadiene
Ethylbenzene
9.93
5.53
0.87
-------
Table 7-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Colorado Monitoring Sites
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer
Hazard
Approximation
(HQ)
Grand Junction, Colorado (Mesa County) - GPCO
Toluene
Xylenes
Benzene
Formaldehyde
Methanol
Hexane
Acetaldehyde
Ethylbenzene
Hydrochloric acid
1,3 -Butadiene
240.58
188.54
140.94
112.12
88.05
50.96
45.52
41.56
27.54
14.18
Acrolein
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Benzene
Naphthalene
Arsenic, PM
Xylenes
Hydrochloric acid
Manganese, PM
553,576.79
11,440.45
7,087.62
5,058.01
4,698.01
2,543.73
2,443.88
1,885.37
1,376.84
1,158.03
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Benzene
Acrylonitrile
Trichloroethylene
Tetrachloroethylene
Carbon Tetrachloride
Chloroform
0.28
0.27
0.07
0.05
0.04
0.03
0.02
0.01
0.01
0.01
Battlement Mesa, Colorado (Garfield County) - BMCO
Toluene
Formaldehyde
Xylenes
Benzene
Hexane
Acetaldehyde
Methanol
Acrolein
Ethylbenzene
1,3 -Butadiene
419.91
324.22
321.33
269.17
82.14
79.93
60.71
40.42
27.66
16.04
Acrolein
Formaldehyde
Benzene
Acetaldehyde
1,3 -Butadiene
Xylenes
Naphthalene
Cyanide Compounds, gas
Lead, PM
Arsenic, PM
2,021,060.94
33,083.40
8,972.23
8,880.90
8,021.37
3,213.31
2,008.12
988.69
430.70
233.88
-------
Table 7-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Colorado Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer
Hazard
Approximation
Pollutant (HQ)
Silt, Colorado (Garfield County) - BRCO
Toluene
Formaldehyde
Xylenes
Benzene
Hexane
Acetaldehyde
Methanol
Acrolein
Ethylbenzene
1,3 -Butadiene
419.91
324.22
321.33
269.17
82.14
79.93
60.71
40.42
27.66
16.04
Acrolein
Formaldehyde
Benzene
Acetaldehyde
1,3 -Butadiene
Xylenes
Naphthalene
Cyanide Compounds, gas
Lead, PM
Arsenic, PM
2,021,060.94
33,083.40
8,972.23
8,880.90
8,021.37
3,213.31
2,008.12
988.69
430.70
233.88
Benzene 0.03
1,3-Butadiene 0.01
Parachute, Colorado (Garfield County) - PACO
Toluene
Formaldehyde
Xylenes
Benzene
Hexane
Acetaldehyde
Methanol
Acrolein
Ethylbenzene
1,3 -Butadiene
419.91
324.22
321.33
269.17
82.14
79.93
60.71
40.42
27.66
16.04
Acrolein
Formaldehyde
Benzene
Acetaldehyde
1,3 -Butadiene
Xylenes
Naphthalene
Cyanide Compounds, gas
Lead, PM
Arsenic, PM
2,021,060.94
33,083.40
8,972.23
8,880.90
8,021.37
3,213.31
2,008.12
988.69
430.70
233.88
Benzene 0.05
1,3-Butadiene 0.04
Ethylbenzene <0.01
-------
Table 7-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Colorado Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer
Hazard
Approximation
(HQ)
Rifle, Colorado (Garfield County) - RICO
Toluene
Formaldehyde
Xylenes
Benzene
Hexane
Acetaldehyde
Methanol
Acrolein
Ethylbenzene
1,3 -Butadiene
419.91
324.22
321.33
269.17
82.14
79.93
60.71
40.42
27.66
16.04
Acrolein
Formaldehyde
Benzene
Acetaldehyde
1,3 -Butadiene
Xylenes
Naphthalene
Cyanide Compounds, gas
Lead, PM
Arsenic, PM
2,021,060.94
33,083.40
8,972.23
8,880.90
8,021.37
3,213.31
2,008.12
988.69
430.70
233.88
1,3 -Butadiene
Benzene
Ethylbenzene
0.09
0.04
0.01
-------
The pollutants listed in Tables 7-7 and 7-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective monitoring site sampled. As
discussed in Section 7.3, GPCO sampled for VOCs, carbonyl compounds, PAHs, and hexavalent
chromium; the Garfield County sites sampled for SNMOCs and carbonyl compounds only. In
addition, the cancer risk and noncancer hazard approximations are limited to those pollutants
with enough data to meet the criteria for annual averages to be calculated. A more in-depth
discussion of this analysis is provided in Section 3.5.5.3. Similar to the cancer risk and
noncancer hazard approximations, this analysis may help policy-makers prioritize their air
monitoring activities.
Observations from Table 7-7 include the following:
Benzene, formaldehyde, and acetaldehyde are the highest emitted pollutants with
cancer UREs in Mesa County. These same pollutants also topped the list for Garfield
County, although not in the same order. Note that the quantity emitted for each
pollutant was roughly twice as high in Garfield County than Mesa County.
The two pollutants with the highest toxicity-weighted emissions (of the pollutants
with cancer UREs) are formaldehyde and benzene for both Mesa and Garfield
Counties. These two counties have eight pollutants in common among the pollutants
with the highest toxicity-weighted emissions.
Seven of the highest emitted pollutants also have the highest toxicity-weighted
emissions in Mesa County while eight of the highest emitted pollutants also have the
highest toxicity-weighted emissions in Mesa County.
For GPCO, six of the 10 pollutants with the highest cancer risk approximations also
appear on both emissions-based lists for Mesa County. In addition, POM, Group 2b is
the eighth highest emitted "pollutant" in Mesa County and ranks sixth for toxicity-
weighted emissions. POM, Group 2b includes several PAHs sampled for at GPCO
including acenaphthene, which has the ninth highest cancer risk approximation for
GPCO.
Where cancer risk approximations could be calculated for the Garfield County sites,
all of the pollutants of interest listed appear on both emissions-based lists.
POM, Groups 2b, 3, 5a, and 6 appear on Garfield County's emissions-based lists.
PAHs were not sampled at the Garfield County sites.
7-58
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Observations from Table 7-8 include the following:
Toluene is the highest emitted pollutant with a noncancer RfC in both Mesa and
Garfield Counties, although the emissions are higher in Garfield County. These two
counties have an additional eight pollutants in common on their lists of highest
emitted pollutants with noncancer RfCs.
The two pollutants with the highest toxi city-weighted emissions (of the pollutants
with noncancer RfCs) for both counties are acrolein and formaldehyde. Although
acrolein was sampled for at GPCO, this pollutant was excluded from the pollutants of
interest designation, and thus subsequent risk-based screening evaluations, due to
questions about the consistency and reliability of the measurements, as discussed in
Section 3.2.
Six of the 10 highest emitted pollutants in Mesa County also have the highest
toxi city-weighted emissions. Six of the 10 highest emitted pollutants in Garfield
County (including acrolein) also have the highest toxicity-weighted emissions. This is
the only county for which acrolein appears among the highest emitted pollutants.
Formaldehyde, acetaldehyde, benzene, and 1,3-butadiene appear on all three lists for
GPCO. Additionally, naphthalene appears among the pollutants with the highest
noncancer hazard approximations and highest toxicity-weighted emissions, but is not
among the highest emitted pollutants with a noncancer RfC in Mesa County.
Benzene and 1,3-butadiene appear on all three lists for the Garfield County sites.
Ethylbenzene, a pollutant of interest for PACO and RICO but not BRCO, is one of
the highest emitted pollutants in Garfield County, but is not among the most toxic.
7.6 Summary of the 2011 Monitoring Data for the Colorado Monitoring Sites
Results from several of the data treatments described in this section include the
following:
ปซป Twenty-three pollutants failed screens for GPCO. The number of pollutants failing
screens for the Garfield County sites ranged from four to five.
ปซป The pollutants with the highest annual average concentrations for GPCO were
formaldehyde, acetaldehyde, and benzene. These were also the only pollutants with
annual average concentrations greater than 1 jug/m3. Benzene had the highest annual
average concentration for each of the Garfield County sites.
*ป* GPCO has the highest annual average concentrations of naphthalene and
benzo(a)pyrene among allNMP sites sampling PAHs.
ปซป Benzene concentrations at GPCO have an overall decreasing trend. In recent years,
concentrations ofhexavalent chromium have increased at GPCO while
concentrations of formaldehyde have decreased.
7-59
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8.0 Site in the District of Columbia
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Washington, D.C., and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
8.1 Site Characterization
This section characterizes the Washington, D.C. monitoring site by providing
geographical and physical information about the location of the site and the surrounding area.
This information is provided to give the reader insight regarding factors that may influence the
air quality near the site and assist in the interpretation of the ambient monitoring measurements.
Figure 8-1 is a composite satellite image retrieved from ArcGIS Explorer showing the
monitoring site in its urban location. Figure 8-2 identifies nearby point source emissions
locations by source category, as reported in the 2008 NEI for point sources. Note that only
sources within 10 miles of the site are included in the facility counts provided in Figure 8-2. A
10-mile boundary was chosen to give the reader an indication of which emissions sources and
emissions source categories could potentially have a direct effect on the air quality at the
monitoring site. Further, this boundary provides both the proximity of emissions sources to the
monitoring site as well as the quantity of such sources within a given distance of the site. Sources
outside the 10-mile radius are still visible on the map, but have been grayed out in order to show
emissions sources just outside the boundary. Table 8-1 provides supplemental geographical
information such as land use, location setting, and locational coordinates.
3-1
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Figure 8-1. Washington, B.C. (WADC) Monitoring Site
oo
to
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Figure 8-2. NEI Point Sources Located Within 10 Miles of WADC
^.Montgomery / Prince George's \
CountV / County ,
77-20'drW 77'15'0'W 77'1CrO*Vtf TT'S'ITW 77-fl'trW 76"55T3*W
Note: Due to facility density and collocation, the total facilities
i displayed may not represent all facilities within the area of interest.
@ WADC NATTS site 10 rnile radius | j County boundary
Source Category Group (No. of Facilities)
ts Air-conditioning/Refrigeration (2)
-f Aircraft Operations (27)
I Asphalt Processing/Roofing Manufacturing (3)
* Electricity Generation via Combustion (3)
F Food Processing/Agriculture (1)
13 Hospital (5)
^ Institutional - school (10)
A Military Base/National Security (5)
? Miscellaneous Commercial/Industrial (18)
P Printing/Publishing (5)
* Transportation and Marketing of Petroleum Products (1)
8-3
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Table 8-1. Geographical Information for the Washington, D.C. Monitoring Site
Site
Code
WADC
AQS Code
11-001-0043
Location
Washington
County
District
Of
Columbia
Micro- or
Metropolitan
Statistical Area
Washington-
Arlington-
Alexandria, DC-
VA-MD-WVMSA
Latitude
and
Longitude
38.921847,
-77.013178
Land Use
Commercial
Location
Setting
Urban/City
Center
Additional Ambient Monitoring Information1
Arsenic, CO, VOCs, SO2, NOy, NO, NO2, NOX,
PAMS, Carbonyl compounds, O3, Meteorological
parameters, PM10, PM25, PM10 Speciation, Black
carbon, PM Coarse, PM2 5 Speciation.
BOLD ITALICS = EPA-designated NATTS Site
oo
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Figure 8-1 shows that the WADC monitoring site is located in an open field at the
southeast of end of the McMillan Water Reservoir in Washington, D.C. It is also located near
several heavily traveled roadways. The site is located in a commercial area, and is surrounded by
a hospital, a cemetery, and a university. As Figure 8-2 shows, WADC is surrounded
predominantly by sources in the aircraft operations source category. This category includes
airports as well as small runways, heliports, or landing pads. Aside from aircraft operations, the
source category with the highest number of sources within 10 miles of the WADC monitoring
site is schools. The closest sources to WADC are hospitals and heliports at hospitals.
Table 8-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Washington D.C. monitoring site. Table 8-2 includes county-
level population and vehicle registration information. Table 8-2 also includes a county-level
vehicle registration-to-population ratio, which was calculated to represent the number of vehicles
per person within the District of Columbia. In addition, the population within 10 miles of the site
is presented, based on postal code population data estimates. An estimate of 10-mile vehicle
ownership was then determined by applying the county-level vehicle registration-to-population
ratio to the 10-mile population surrounding the monitoring site. Table 8-2 also contains traffic
volume information for WADC. Finally, Table 8-2 presents the county-level daily VMT for the
District of Columbia.
Table 8-2. Population, Motor Vehicle, and Traffic Information for the Washington, D.C.
Monitoring Site
Site
WADC
Estimated
County
Population1
617,996
County-level
Vehicle
Registration2
213,232
Vehicles per
Person
(Registration:
Population)
0.35
Population
within 10
miles3
1,931,834
Estimated
10 mile
Vehicle
Ownership
666,556
Annual
Average
Daily
Traffic4
7,700
County-
level
Daily
VMT5
9,775,000
1 County-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2 County-level vehicle registration reflects 2010 data from the Federal Highway Administration (FHWA, 2011)
3 10-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4 AADT reflects 2009 data from the District DOT (DC DOT, 2011)
5 County-level VMT reflects 2011 data from the District DOT (DC DOT, 2012)
BOLD ITALICS = EPA-designaled NATTS Site
8-5
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Observations from Table 8-2 include the following:
The District's population is in the middle of the range compared to other counties
with NMP sites. Its 10-mile population however, ranks fifth highest and is three times
higher than its county-level population.
The District-level vehicle registration is in the bottom third compared to other
counties with NMP sites, while its 10-mile ownership is in the middle of the range.
The vehicle-per-person ratio is among the lowest compared to other NMP sites.
The traffic volume experienced near WADC is in the bottom third compared to other
NMP monitoring sites. The traffic volume provided is for the intersection of Bryant
Street and First Street.
The district-level VMT is in the middle-third compared to other county-level VMT,
where VMT is available.
8.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Washington, D.C. on sample days, as well as over the course of the year.
8.2.1 Climate Summary
Located on the Potomac River that divides Virginia and Maryland, the capital enjoys all
four seasons, although its weather is somewhat variable. Summers are warm and often humid,
where southerly winds prevail, which can be accentuated by the urban heat island effect. Winters
are typical of the Mid-Atlantic region, where cool, blustery air masses are common followed by
a fairly quick return to mild temperatures. Precipitation is evenly distributed across the seasons
(Bair, 1992).
8.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station to WADC is located at Ronald Reagan
Washington National Airport (WBAN 13743). Additional information about the National
Airport weather station, such as the distance between the site and the weather station, is provided
in Table 8-3. These data were used to determine how meteorological conditions on sample days
vary from conditions experienced throughout the year.
8-6
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Table 8-3. Average Meteorological Conditions near the Washington, D.C. Monitoring Site
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Washington, D.C. - WADC
Ronald Reagan
Washington
National Airport
13743
(38.87, -77.03)
4.07
miles
183ฐ
(S)
Sample
Day
2011
66.4
ฑ4.3
67.7
ฑ1.9
58.7
ฑ4.0
59.6
ฑ1.8
44.9
ฑ4.5
46.4
ฑ1.9
51.9
ฑ3.7
52.9
ฑ1.6
63.5
ฑ3.7
64.9
ฑ1.5
1017.0
ฑ1.7
1016.5
ฑ0.7
7.5
ฑ0.8
7.0
ฑ0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
oo
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Table 8-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 8-3 is the
95 percent confidence interval for each parameter. As shown in Table 8-3, average
meteorological conditions on sample days were generally representative of average weather
conditions throughout the year. The largest differences were calculated for dew point
temperature and relative humidity, although the differences were slight. These differences may
result from make-up samples collected in November and December 2011.
8.2.3 Back Trajectory Analysis
Figure 8-3 is the composite back trajectory map for days on which samples were
collected at the WADC monitoring site in 2011. Included in Figure 8-3 are four back trajectories
per sample day. Figure 8-4 is the corresponding cluster analysis. An in-depth description of these
maps and how they were generated is presented in Section 3.5.2.1. For the composite map, each
line represents the 24-hour trajectory along which a parcel of air traveled toward the monitoring
site on a given sample day and time, based on an initial height of 50 meters AGL. For the cluster
analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 8-3 and 8-4 represents 100 miles.
-------
Figure 8-3. 2011 Composite Back Trajectory Map for WADC
y
Figure 8-4. Back Trajectory Cluster Map for WADC
8-9
-------
Observations from Figures 8-3 and 8-4 include the following:
Back trajectories originated from a variety of directions at WADC. The most
common direction of trajectory origin appears to be from the northwest.
The 24-hour air shed domain for WADC was comparable in size to many other NMP
monitoring sites. The farthest away a back trajectory originated was over the Upper
Peninsula of Michigan, or nearly than 700 miles away. However, the average
trajectory length was 239 miles and 88 percent of back trajectories originated within
400 miles of the site.
The cluster analysis confirms that back trajectories originating from the northwest
were most common (26 percent). The cluster trajectory originating from the west of
WADC (16 percent) represents back trajectories originating over Virginia and West
Virginia and generally less than 200 miles in length. Twelve percent of trajectories
originated to the north of WADC, another 10 percent originated to the south over
North Carolina, and another 7 percent originated from the east and offshore. The
short cluster (28 percent) represents trajectories originating within 200 miles of the
site and of varying direction, but most often to the south of the site as well as longer
trajectories originating off the coast of North Carolina and Virginia.
8.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Ronald Reagan Washington
National Airport were uploaded into a wind rose software program to produce customized wind
roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions using
"petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 8-5 presents a map showing the distance between the NWS station and WADC,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 8-5 also presents three different wind roses for the
WADC monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
8-10
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Figure 8-5. Wind Roses for the Ronald Reagan Washington National Airport Weather
Station near WADC
Distance between WADC and NWS Station
2001-2010 Historical Wind Rose
4-
......ป.ซ.., / I
* 1
2011 Wind Rose
Sample Day Wind Rose
8-11
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Observations from Figure 8-5 for WADC include the following:
The NWS weather station at Washington National Airport is located approximately
4.1 miles to the south of WADC. Note that between WADC and Washington
National is the city of Washington and the Potomac River.
Historically, southerly to south-south westerly winds account for approximately
25 percent of wind observations near WADC, while northwesterly to northerly winds
account for another 25 percent of observations. Calm winds (< 2 knots) were
observed for less than 10 percent of the hourly measurements.
The wind patterns on both the full-year and sample day wind roses are similar to the
wind patterns shown on the historical wind rose, although southerly winds accounted
for a slightly higher percentage of wind observations in 2011. The similarities in the
wind roses indicate that wind patterns in 2011 were similar to what is expected
climatologically near this site.
8.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Washington, D.C.
monitoring site in order to allow analysts and readers to focus on a subset of pollutants through
the context of risk. Each pollutant's preprocessed daily measurement was compared to its
associated risk screening value. If the concentration was greater than the risk screening value,
then the concentration "failed the screen." Pollutants of interest are those for which the
individual pollutant's total failed screens contribute to the top 95 percent of the site's total failed
screens. In addition, if any of the NATTS MQO Core Analytes measured by the monitoring site
did not meet the pollutant of interest criteria based on the preliminary risk-based screening, that
pollutant was added to the list of site-specific pollutants of interest. A more in-depth description
of the risk-based screening process is presented in Section 3.2.
Table 8-4 presents the results of the preliminary risk-based screening process. The
pollutants that failed at least one screen and contributed to 95 percent of the total failed screens
for the WADC monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. WADC sampled for hexavalent chromium and
PAHs.
8-12
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Table 8-4. Risk-Based Screening Results for the Washington, D.C. Monitoring Site
Pollutant
Screening
Value
(Ug/m3)
# of Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Washington, D.C. - WADC
Naphthalene
0.029
Total
61
61
61
61
100.00
100.00
100.00
100.00
Observations from Table 8-4 include the following:
Naphthalene is the only pollutant to failed screens for WADC. Naphthalene failed
100 percent of its screens.
Benzo(a)pyrene and hexavalent chromium were added as pollutants of interest for
WADC because they are the other NATTS MQO Core Analytes measured by this
site. These two pollutants are not shown in Table 8-4 but are shown in subsequent
tables in the sections that follow.
8.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Washington D.C. monitoring site. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest, where the data meet the applicable criteria. Concentration
averages for select pollutants are also presented graphically to illustrate how the site's
concentrations compare to the program-level averages, as presented in Section 4.1. In addition,
concentration averages for select pollutants are presented from previous years of sampling in
order to characterize concentration trends at the site. Additional site-specific statistical
summaries for WADC are provided in Appendices M and O.
8.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for the Washington, D.C. monitoring site, as described in Section 3.1. The quarterly average of a
particular pollutant is simply the average concentration of the preprocessed daily measurements
over a given calendar quarter. Quarterly average concentrations include the substitution of zeros
for all non-detects. A site must have a minimum of 75 percent valid samples of the total number
of samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
8-13
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could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for WADC are presented
in Table 8-5, where applicable. Note that if a pollutant was not detected in a given calendar
quarter, the quarterly average simply reflects "0" because only zeros substituted for non-detects
were factored into the quarterly average concentration.
Table 8-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest
for the Washington, D.C. Monitoring Site
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Washington, D.C. - WADC
Benzo(a)pyrene
Hexavalent Chromium
Naphthalene
37/61
49/61
61/61
0.07
ฑ0.04
0.02
ฑ0.01
67.83
ฑ17.12
0.02
ฑ0.02
0.02
ฑ0.01
65.20
ฑ 12.60
0.03
ฑ0.02
0.02
ฑ0.01
123.41
ฑ 50.74
0.09
ฑ0.04
0.02
ฑ0.01
137.87
ฑ 46.65
0.06
ฑ0.02
0.02
ฑ0.01
102.71
ฑ 20.46
Observations for WADC from Table 8-5 include the following:
Naphthalene was detected in every PAH sample collected at WADC while
benzo(a)pyrene was detected in approximately 60 percent of the PAH samples
collected. Hexavalent chromium was detected in 80 percent of the samples collected.
The annual average concentration of naphthalene is significantly higher than the
annual average concentrations of benzo(a)pyrene and hexavalent chromium.
Benzo(a)pyrene concentrations appear higher during the colder months of the year, as
indicated by the quarterly averages. Of the 14 measurements of benzo(a)pyrene
greater than or equal to 0.1 ng/m3, eight were measured during the fourth quarter and
four during the first quarter (and one each in the second and third quarters). In all,
there were eight measured detections of this pollutant during the first quarter of 2011,
five during the second quarter, eight during the third quarter, and 16 during the fourth
quarter. The number of non-detects was highest during the warmer quarters of the
year (five, nine, seven, and three, respectively).
Concentrations of hexavalent chromium were relatively consistent across the year.
The third and fourth quarterly average concentrations of naphthalene are twice as
high as the first and second quarterly average concentrations. The maximum
naphthalene concentration was measured at WADC on August 31, 2011 (416 ng/m3).
Of the 19 naphthalene concentrations greater than 100 ng/m3 measured at WADC, 15
were measured during the third and fourth quarters; conversely, of the 15 naphthalene
8-14
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concentrations less than 50 ng/m3 measured at WADC, 10 were measured during the
first and second quarters. However, both relatively high and low naphthalene
concentrations were measured in each quarter of 2011.
8.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzo(a)pyrene,
hexavalent chromium, and naphthalene were created for WADC. Figures 8-6 through 8-8
overlay the site's minimum, annual average, and maximum concentrations onto the program-
level minimum, first quartile, median, average, third quartile, and maximum concentrations, as
described in Section 3.5.3.
Figure 8-6. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
i
Concentration (ng/m3)
Program: IstQuartile
2nd Quartile
3rd Quartile
D
4th Quartile
Average
Site:
Site Average
Site Minimum/Maximum
o
Figure 8-7. Program vs. Site-Specific Average Hexavalent Chromium Concentration
I
0.15
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
8-15
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Figure 8-8. Program vs. Site-Specific Average Naphthalene Concentration
WADC
Program Max Concentration =779 ng/m3
50
100
200 250 300
Concentration (ng/m3)
35:
45:
5::
Program: IstQuartile 2ndQuartile 3rd Quartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
Observations from Figures 8-6 through 8-8 include the following:
Figure 8-6 is the box plot for benzo(a)pyrene. Note that the program-level first
quartile for this pollutant is zero and is not visible on this box plot. The box plot
shows that the annual average concentration for WADC is less than the program-
level average concentration but greater than the program-level median
concentration. Figure 8-6 also shows that the maximum concentration measured
at WADC is considerably less than the maximum concentration measured across
the program. There were several non-detects of benzo(a)pyrene measured at
WADC.
Figure 8-7 is the box plot for hexavalent chromium. Figure 8-7 shows that
WADC's annual average concentration (0.0167 ng/m3) is less than the program-
level average (0.0237 ng/m3) and just less than the program-level median
concentration (0.0178 ng/m3). The maximum concentration measured at WADC
is less than the program-level maximum concentration. There were several non-
detects of hexavalent chromium measured at WADC.
Figure 8-8 is the box plot for naphthalene. Note that the program-level maximum
concentration (779 ng/m3) is not shown directly on the box plot because the scale
of the box plot would be too large to readily observe data points at the lower end
of the concentration range. Thus, the scale has been reduced to 500 ng/m3.
Figure 8-8 shows that the annual naphthalene average for WADC is greater than
the program-level average concentration and just less than the program-level third
quartile. The annual average concentration of naphthalene for WADC ranked 12th
compared to other NMP sites sampling PAHs. The maximum naphthalene
concentration measured at WADC is less than the program-level maximum
concentration. The minimum concentration measured at WADC is just less than
the program-level first quartile. There were no non-detects of naphthalene
measured at WADC or across the program.
8-16
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8.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. WADC has sampled hexavalent chromium under the NMP since 2005. Thus,
Figure 8-9 presents the annual statistical metrics for hexavalent chromium for WADC. The
statistical metrics presented for assessing trends include the substitution of zeros for non-detects.
WADC did not begin sampling PAHs until 2008; thus, the trends analysis was not conducted for
the pollutants for these methods.
Figure 8-9. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at WADC
The maximum
concentration for
2006 is 0.645 ng/m3
5th Percentile - Minimum Median - Maximum 95th Percentile *' Average
Observations from Figure 8-9 for hexavalent chromium measurements at WADC include
the following:
Sampling for hexavalent chromium began in March 2005 but because fewer than
85 percent of possible samples were collected, Figure 8-9 excludes 2005 data and
begins with 2006.
The maximum hexavalent chromium concentration shown was measured on
July 4, 2006 (0.645 ng/m3).
8-17
-------
The average hexavalent chromium concentration decreased significantly from 2006 to
2007 and remained steady through 2009. During this time, the median decreased to
zero for 2008 and 2009, indicating that at least 50 percent of the measurements were
non-detects. The percentage of non-detects increased from 32 percent in 2006 to a
maximum of 72 percent in 2009. The substitution of zeros for these non-detects is the
likely reason for this decrease in these statistical parameters. The number of non-
detects decreased in 2010 (33 percent) and again in 2011 (20 percent); accordingly,
with fewer zero substitutions for non-detects, the median and average concentrations
increased.
The maximum concentrations are roughly the same across the last three years of
sampling (approximately 0.08 ng/m3). However, the 95th percentile exhibits mon
fluctuations, indicating more variability among the majority of measurements.
8.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
WADC monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
8.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Washington D.C. monitoring site to the ATSDR MRLs, where available. As described in
Section 3.3, MRLs are noncancer health risk benchmarks and are defined for three exposure
periods: acute (exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and
chronic (exposures of 1 year or greater). The preprocessed daily measurements of the pollutants
of interest were compared to the acute MRLs; the quarterly averages were compared to the
intermediate MRLs; and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
8-18
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8.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for WADC and where annual average concentrations could
be calculated, risk was examined by calculating cancer risk and noncancer hazard
approximations. These approximations can be used as risk estimates for cancer and noncancer
effects attributable to the pollutants of interest. Although the use of these approximations is
limited, they may help identify where policy-makers may want to shift or confirm their air-
monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer risk and
noncancer hazard approximations are calculated and what limitations are associated with them.
Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer hazard
approximations are presented in Table 8-6, where applicable. Cancer risk approximations are
presented as probabilities while the noncancer hazard approximations are ratios and thus, unitless
values.
Table 8-6. Risk Approximations for the Washington, D.C. Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
Washin
Benzo(a)pyrene
Hexavalent Chromium
Naphthalene
0.00176
0.012
0.000034
0.0001
0.003
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
gton, D.C. - WADC
37/61
49/61
61/61
0.06
ฑ0.02
0.02
ฑ<0.01
102.71
ฑ 20.46
0.10
0.20
3.49
<0.01
0.03
= a Cancer URE or Noncancer RfC is not available.
Observations for WADC from Table 8-6 include the following:
As discussed in Section 8.4.1, naphthalene's annual average concentration is four
orders of magnitude higher than the annual average concentrations for the other
two pollutants of interest.
Naphthalene's cancer risk approximation is greater than 1.0 in-a-million
(3.49 in-a-million). Its noncancer hazard approximation is significantly less than
1.0 (0.03), indicating no adverse health effects are expected from this pollutant.
The cancer risk approximation for benzo(a)pyrene is considerably less than the
cancer risk approximation for naphthalene (0.10 in-a-million). A noncancer RfC
is not available for benzo(a)pyrene; thus, a noncancer hazard approximation could
not be calculated.
8-19
-------
The cancer surrogate risk approximation based on hexavalent chromium's annual
average concentration is less than 1.0 in-a-million (0.20 in-a-million). The
noncancer hazard approximation is also low (<0.01).
8.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 8-7 and 8-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 8-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 8-6. Table 8-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 8-6.
The pollutants listed in Tables 8-7 and 8-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 8.3, WADC sampled for PAHs and hexavalent chromium. In addition, the cancer risk
and noncancer hazard approximations are limited to those pollutants with enough data to meet
the criteria for annual averages to be calculated. A more in-depth discussion of this analysis is
provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this
analysis may help policy-makers prioritize their air monitoring activities.
8-20
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Table 8-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs
the Washington, D.C. Monitoring Site
for
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity- Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Washington, D.C. - WADC
Benzene
Formaldehyde
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group la
POM, Group 6
149.75
139.99
83.08
76.80
24.93
14.40
4.38
3.56
0.39
0.35
Formaldehyde
Benzene
1,3 -Butadiene
POM, Group 3
Naphthalene
POM, Group 2b
Hexavalent Chromium, PM
Ethylbenzene
Acetaldehyde
POM, Group 5a
1.82E-03
1.17E-03
7.48E-04
6.38E-04
4.90E-04
3.13E-04
2.01E-04
1.92E-04
1.83E-04
1.32E-04
Naphthalene
Hexavalent Chromium
Benzo(a)pyrene
3.49
0.20
0.10
oo
to
-------
Table 8-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Washington, D.C. Monitoring Site
oo
to
to
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer
Hazard
Approximation
Pollutant (HQ)
Washington, D.C. - WADC
Toluene
Methanol
Xylenes
Benzene
Formaldehyde
Hexane
Acetaldehyde
Ethylbenzene
Ethylene glycol
1,3 -Butadiene
433.60
342.72
309.21
149.75
139.99
93.23
83.08
76.80
36.01
24.93
Acrolein
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Benzene
Naphthalene
Xylenes
Nickel, PM
Arsenic, PM
Propionaldehyde
361,586.14
14,284.26
12,467.17
9,231.05
4,991.64
4,799.27
3,092.12
1,910.51
1,536.26
966.01
Naphthalene 0.03
Hexavalent Chromium O.01
-------
Observations from Table 8-7 include the following:
Benzene and formaldehyde are the highest emitted pollutants with cancer UREs in the
District of Columbia. Formaldehyde and benzene are the pollutants with the highest
toxi city-weighted emissions (of the pollutants with cancer UREs).
Seven of the highest emitted pollutants also have the highest toxi city-weighted
emissions.
Naphthalene is the only pollutant sampled for at WADC that appears on both
emissions-based lists. Naphthalene is the sixth highest emitted pollutant with a cancer
URE in the District of Columbia and has the fifth highest toxicity-weighted emissions
(of the pollutants with cancer UREs).
While hexavalent chromium is not one of the 10 highest emitted pollutants in the
District, its toxi city-weighted emissions ranked seventh highest (of the pollutants with
cancer UREs).
Several POM Groups are among the highest emitted "pollutants" in the District
and/or rank among the highest toxicity-weighted emissions. POM, Group 5a, which
includes benzo(a)pyrene, appears on both emissions-based lists for the District. POM,
Group 2b includes several PAHs sampled for at WADC including acenaphthylene,
fluoranthene, fluorene, and perylene. POM, Group 6 includes benzo(a)anthracene and
indeno(l,2,3-cd)pyrene. None of the PAHs included in POM, Groups 2b or 6 were
identified as pollutants of interest for WADC.
Observations from Table 8-8 include the following:
Toluene, methanol, and xylenes are the highest emitted pollutants with noncancer
RfCs in the District of Columbia.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, formaldehyde, and 1,3-butadiene.
Five of the highest emitted pollutants in the District of Columbia also have the
highest toxicity-weighted emissions.
Naphthalene has the highest noncancer hazard approximation for WADC (albeit low).
Naphthalene has the sixth highest toxicity-weighted emissions but is not one of the 10
highest emitted pollutants (of the pollutants with noncancer RfCs).
Hexavalent chromium, the only other pollutant of interest for which a noncancer RfC
is available, does not appear on either emissions-based list.
8-23
-------
8.6 Summary of the 2011 Monitoring Data for WADC
Results from several of the data treatments described in this section include the
following:
ปซป Naphthalene was the only pollutant to fail screens for WADC. While naphthalene was
the only pollutant of interest identified via the risk screening process, benzo(a)pyrene
and hexavalent chromium were added to WADC"s pollutants of interest because they
are NATTSMQO Core Analytes.
*ป* Of the site-specific pollutants of the interest, naphthalene had the highest annual
average concentration for WADC. Naphthalene concentrations were highest during
the secondhalfoftheyear.
ปซป The number ofnon-detects of hexavalent chromium measured at WADC has been
decreasing over recent years of sampling.
8-24
-------
9.0 Sites in Florida
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS and UATMP sites in Florida, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
9.1 Site Characterization
This section characterizes the Florida monitoring sites by providing geographical and
physical information about the location of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
The five Florida sites are located in two different urban areas. Three sites (AZFL, SKFL,
and SYFL) are located in the Tampa-St. Petersburg-Clearwater, FL MSA. ORFL and PAFL are
located in the Orlando-Kissimmee, FL MSA. Figures 9-1 through 9-3 are composite satellite
images retrieved from ArcGIS Explorer showing the Tampa/St. Petersburg monitoring sites in
their urban and rural locations. Figure 9-4 identifies nearby point source emissions locations that
surround these three sites by source category, as reported in the 2008 NEI for point sources. Note
that only sources within 10 miles of the sites are included in the facility counts provided in
Figure 9-4. A 10-mile boundary was chosen to give the reader an indication of which emissions
sources and emissions source categories could potentially have a direct effect on the air quality at
the monitoring sites. Further, this boundary provides both the proximity of emissions sources to
the monitoring sites as well as the quantity of such sources within a given distance of the sites.
Sources outside the 10-mile radii are still visible on the map, but have been grayed out in order
to show emissions sources just outside the boundary. Figures 9-5 and 9-6 are the composite
satellite images for the two sites in the Orlando area and Figure 9-7 is the emissions sources map
for these sites. Table 9-1 provides supplemental geographical information such as land use,
location setting, and locational coordinates.
9-1
-------
Figure 9-1. St. Petersburg, Florida (AZFL) Monitoring Site
to
-------
Figure 9-2. Pinellas Park, Florida (SKFL) Monitoring Site
-------
Figure 9-3. Plant City, Florida (SYFL) Monitoring Site
-------
Figure 9-4. NEI Point Sources Located Within 10 Miles of the
Tampa/St. Petersburg, Florida Monitoring Sites
82'45'trW 82'40'CrW 82'35'0'W 82'30tTW B2'25'0'W
82 55XTW 82'50'0-W B2'45T)-W
Legend
AZFLUATMPsite
82 35XJ-W a2'3(K 82'25' Air-conditioning/Refrigeration (1)
4" Aircraft Operations (16)
I Asphalt Processing/Roofing Manufacturing (1)
0 Auto Body Shop/Painters (2)
K Automobile/Truck Manufacturing (2)
6 Bakery (1)
i Boat Manufacturing (4)
~ Brick Manufacturings Structural Clay (1)
Building Construction (1)
C Chemical Manufacturing (2)
Concrete Batch Plant (1)
f Electricity Generation via Combustion (2)
E Electroplating, Plating, Polishing, Anodizing, and Coloring (1)
ฉ Fabricated Metal Products (10)
F Food Processing/Agriculture (6)
Gasoline/Diesel Service Station (1)
Hospital (1)
Hot Mix A$phalt Plant (2)
Industrial Machinery and Equipment (1)
Institutional - school (2)
Miscellaneous Commerciain'ndustrial (3)
Miscellaneous Manufacturing (3)
Municipal Waste Cornbustor (2)
Oil and/or Gas Production (1)
Pharmaceutical Manufacturing (1)
Printing/Publishing (12)
Pulp and Paper Plant/Wood Products (2)
Rubber and Miscellaneous Plaslics Products (3)
Secondary Melal Processing (3)
Solid Waste Disposal - Commercial/Institutional (1)
Surface Coating (4)
Telecommunications (2)
Transportation Equipment (1}
Wastewater Treatment (2)
9-5
-------
Figure 9-5. Winter Park, Florida (ORFL) Monitoring Site
-------
Figure 9-6. Orlando, Florida (PAFL) Monitoring Site
-------
Figure 9-7. NEI Point Sources Located Within 10 Miles of ORFL and PAFL
Legend
Note: Due to facility density and collocation, the total facilities
displayed may not represent ail facilities within the area of interest
ORFL UATMP site ฎ PAFL UATMP site 1 0 mile radius f 1 County boundary
Source Category Group (No. of Facilities)
-f Aircraft Operations (23)
I Asphalt Processing/Roofing Manufacturing (1)
0 Auto Body Shop/Painters (1)
ft Automobile/Truck Manufacturing (1)
6 Bakery (3)
ฑ Boat Manufacturing (1)
Brick Manufacturing & Structural Clay (1)
A Cement Kiln/Dryer (1)
C Chemical Manufacturing (1)
fl> Dry Cleaning (1)
6 Electrical Equipment (2)
* Electricity Generation via Combustion (1)
E Electroplating, Plating, Polishing, Anodizing, and Coloring (1)
ฉ Fabricated Metal Products (2)
F Food Processing/Agriculture (2)
B Furniture Plant (2)
Gasoline/Diesel Service Station (1)
: Hospital (2)
$ Hot Mix Asphalt Plant (4)
-$ Industrial Machinery and Equipment (2)
^t Institutional - school (3)
V Mineral Products (1)
? Miscellaneous Commercial/Industrial (5)
M Miscellaneous Manufacturing (2)
Oil and/or Gas Production (1}
P Printing/Publishing (2)
H Pulp and Paper Plant/Wood Products (3)
R Rubber and Miscellaneous Plastics Products (3)
S Surface Coating (5)
rr Telecommunications (1)
9-8
-------
Table 9-1. Geographical Information for the Florida Monitoring Sites
Site
Code
AZFL
SKFL
SYFL
ORFL
PAFL
AQS Code
12-103-0018
12-103-0026
12-057-3002
12-095-2002
12-095-1004
Location
St.
Petersburg
Pinellas
Park
Plant City
Winter
Park
Orlando
County
Pinellas
Pinellas
Hillsborough
Orange
Orange
Micro- or
Metropolitan
Statistical Area
Tampa-St.
Petersburg-
Clearwater, FL
Tampa-St.
Petersburg-
Clearwater, FL
Tampa-St.
Petersburg-
Clearwater, FL
Orlando-
Kissimmee, FL
Orlando-
Kissimmee, FL
Latitude
and
Longitude
27.785556,
-82.74
27.850041,
-82.714590
27.96565,
-82.2304
28.596444,
-81.362444
28.550833,
-81.345556
Land Use
Residential
Residential
Residential
Commercial
Commercial
Location
Setting
Suburban
Suburban
Rural
Urban/City
Center
Suburban
Additional Ambient Monitoring Information1
NO, NO2, NOX, VOCs, O3, Meteorological
parameters, PM10, PM10 Speciation, PM25.
VOCs, Meteorological parameters, PM10 Speciation,
Black carbon, PM25 Speciation, PM25.
CO, SO2, NOy, NO, NO2, NOX, VOCs, O3,
Meteorological parameters, PM10, PM10 Speciation,
PM2 5, PM2 5 Speciation, PM Coarse.
CO, SO2, NO, NO2, NOX, VOCs, O3, Meteorological
parameters, PM10, PM25.
Meteorological parameters, PM10, PM25.
VO
BOLD ITALICS = EPA-designated NATTS Site
-------
AZFL is located at Azalea Park in St. Petersburg. Figure 9-1 shows that the area
surrounding AZFL consists of mixed land use, including residential, commercial, and industrial
properties. Heavily traveled roadways are located less than 1 mile from the monitoring site.
AZFL is located just over 1 mile east of Boca Ciega Bay.
SKFL is located in Pinellas Park, north of St. Petersburg. This site is on the property of
Skyview Elementary School near 86th Avenue North. Figure 9-2 shows that SKFL is located in a
primarily residential area. However, a railroad intersects the Pinellas Park Ditch near a
construction company in the bottom left corner of Figure 9-2. Population exposure is the purpose
behind monitoring at this location. This site is the Pinellas County NATTS site.
SYFL is located in Plant City, which is also part of the Tampa-St. Petersburg-Clearwater,
FL MSA, although it is on the eastern outskirts of the area. Unlike the other Florida sites, the
SYFL monitoring site is in a rural area, although, as Figure 9-3 shows, a residential community
and country club lie just to the west of the site. Located to the south of the site is a tank that is
part of the local water treatment facility. This site serves as a background site, although the effect
of increased development in the area is likely being captured by the monitoring site. This site is
the Tampa NATTS site.
Figure 9-4 shows the location of the Tampa/St. Petersburg sites in relation to each other.
SYFL is located the farthest east and AZFL is the farthest west, although SKFL is located within
a few miles of AZFL. A large cluster of point sources is located just north of SKFL. Another
cluster of emissions sources is located about halfway between SYFL and the other two sites,
although grayed out and not included in the facility counts in Figure 9-4. Aircraft operations,
which include airports as well as small runways, heliports, or landing pads; printing and
publishing facilities; and fabricated metal product facilities are the source categories with the
highest number of emissions sources in the Tampa/St. Petersburg area (based on the areas
covered by the 10-mile radii).
ORFL is located in Winter Park, north of Orlando. Figure 9-5 shows that ORFL is
located near Lake Mendsen, east of Lake Killarney and south of Winter Park Village. This site
lies in a commercial area and serves as a population exposure monitor.
9-10
-------
PAFL is located in northern Orlando, on the northwestern edge of the Orlando Executive
Airport property, as shown in Figure 9-6. The area is considered commercial and experiences
heavy traffic. The airport is bordered by Colonial Drive to the north and the East-West
Expressway (Toll Road 408) to the south (although not shown in Figure 9-6). A large shopping
complex is located to the northeast of the site, just north of the airport, between Colonial Drive
and Maguire Boulevard. Interstate-4 runs north-south less than 2 miles to the west of the
monitoring site.
Figure 9-7 shows that ORFL is located a few miles north of PAFL. Most of the point
sources are located on the western side of the 10-mile radii. Although the emissions sources
surrounding ORFL and PAFL are involved in a variety of industries and processes, the aircraft
operations source category has the highest number of emissions sources within 10 miles of these
sites.
Table 9-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Florida monitoring sites. Table 9-2 includes county-level
population and vehicle registration information. Table 9-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 9-2 also
contains traffic volume information for each site. Finally, Table 9-2 presents the county-level
daily VMT for Pinellas, Hillsborough, and Orange Counties.
9-11
-------
Table 9-2. Population, Motor Vehicle, and Traffic Information for the Florida Monitoring
Sites
Site
AZFL
SKFL
SYFL
ORFL
PAFL
Estimated
County
Population1
917,398
1,267,775
1,169,107
County-level
Vehicle
Registration2
877,075
1,135,945
1,056,627
Vehicles per
Person
(Registration:
Population)
0.96
0.90
0.90
Population
within 10
miles3
580,599
705,597
321,686
1,003,806
880,133
Estimated
10-mile
Vehicle
Ownership
555,080
674,583
288,235
907,230
795,455
Annual
Average
Daily
Traffic4
40,500
47,000
10,600
32,500
46,000
County-
level
Daily VMT5
21,395,381
34,351,899
33,325,315
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Florida Department of Highway Safety & Motor
Vehicles (FL DHSMV, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the Florida DOT (FL DOT, 201 la)
5County-level VMT reflects 2011 data for all public roads from the Florida DOT (FL DOT, 201 Ib)
BOLD ITALICS = EPA-designated NATTS Site
Observations from Table 9-2 include the following:
Hillsborough County, where SYFL is located, is the most populous of the Florida
counties with monitoring sites, although Orange County also has over 1 million
people. Broward County ranks just less than Orange County compared to other
counties with NMP sites covered in this report.
Of the five Florida monitoring sites, ORFL has the highest population within 10 miles
of all the Florida sites. ORFL's 10-mile population ranks 12th highest among NMP
sites. Note the difference between SYFL's 10-mile and county-level populations. This
is an example of a site located within a populous county that is not near the
population center.
The vehicle registration counts for two of the three Florida counties are over
1 million, with Hillsborough County having the most and Pinellas County having the
least. The 10-mile ownership estimates are more variable, with SYFL having the least
number of vehicles and ORFL having the most.
The vehicle-per-person ratios range from 0.90 (both Orange and Hillsborough
Counties) to 0.96 (Pinellas County).
The traffic volume near SYFL is the lowest among the Florida sites and highest near
SKFL. Traffic volumes near most of the Florida monitoring sites are in the middle of
the range compared to other NMP sites, with traffic near SYFL being in the bottom
third compared to other NMP sites. The following list provides the roadways or
intersections from which the traffic data were obtained: AZFL - 66th StreetNorth,
north of 9th Street; ORFL - Orlando Avenue, north of Morse Boulevard; PAFL - East
Colonial Drive, between Primrose Road and Bumby Avenue; SKFL - Park
Boulevard, east of 66th Street North; and SYFL - Martin Luther King Jr. Boulevard
(574), east of Mclntosh Road.
9-12
-------
VMT is highest for Hillsborough County and lowest for Pinellas County (among the
Florida sites). The Hillsborough, Orange, and Pinellas County VMTs ranked eighth,
ninth, and 14th highest among counties with NMP sites, respectively.
9.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Florida on sample days, as well as over the course of the year.
9.2.1 Climate Summary
The Tampa and Orlando areas experience very mild winters and warm, humid summers.
Precipitation tends to be concentrated during the summer, as afternoon thunderstorms occur
frequently. Semi-permanent high pressure offshore over the Atlantic Ocean extends westward
towards Florida in the winter, resulting in reduced precipitation amounts. Land and sea breezes
affect coastal locations and the proximity to the Atlantic Ocean or Gulf of Mexico can have a
marked affect on the local meteorological conditions. Florida's orientation and location between
the warm waters of the Gulf of Mexico, the Atlantic Ocean, and Caribbean Sea make it
susceptible to tropical systems (Bair, 1992 and FCC, 2013).
9.2.2 Meteorological Conditions in 2011
Hourly meteorological data from NWS weather stations nearest these sites were retrieved
for 2011 (NCDC, 2011). These data were used to determine how meteorological conditions on
sample days vary from conditions experienced throughout the year. The weather station closest
to the AZFL monitoring site is located at St. Petersburg/Whitted Airport (WBAN 92806); closest
to SYFL is at Plant City Municipal Airport (WBAN 92824); closest to SKFL is at
St. Petersburg/Clearwater International Airport (WBAN 12873); and closest to ORFL and PAFL
is at Orlando Executive Airport (WBAN 12841). Additional information about each of these
weather stations, such as the distance between the sites and the weather stations, is provided in
Table 9-3.
9-13
-------
Table 9-3. Average Meteorological Conditions near the Florida Monitoring Sites
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar
Wind Speed
(kt)
St. Petersburg, Florida - AZFL
St. Petersburg/
Whirled Airport
92806
(27.77, -82.63)
6.77
miles
94ฐ
(E)
Sample
Day
2011
79.6
ฑ2.1
80.4
ฑ0.9
73.6
ฑ2.3
74.2
ฑ0.9
65.1
ฑ2.6
65.4
ฑ1.0
68.3
ฑ2.3
68.7
ฑ0.9
76.1
ฑ2.5
75.4
ฑ1.0
1016.7
ฑ 1.0
1016.5
ฑ0.4
7.6
ฑ0.8
7.3
ฑ0.3
Pinellas Park, Florida - SKFL
St Petersburg-
Clearwater Intl.
Airport
12873
(27.91, -82.69)
4.46
miles
12ฐ
(NNE)
Sample
Day
2011
80.8
ฑ2.2
81.6
ฑ0.9
72.9
ฑ2.3
73.4
ฑ0.9
63.0
ฑ2.6
63.3
ฑ1.0
66.8
ฑ2.2
67.1
ฑ0.9
72.8
ฑ2.2
72.4
ฑ0.9
1017.0
ฑ1.0
1017.0
ฑ0.4
6.6
ฑ0.6
6.5
ฑ0.2
Plant City, Florida - SYFL
Plant City
Municipal Airport
92824
(28.00, -82.16)
4.56
miles
50ฐ
(NE)
Sample
Day
2011
83.2
ฑ2.5
84.7
ฑ0.9
73.0
ฑ2.5
73.9
ฑ0.9
62.9
ฑ2.8
63.5
ฑ1.0
66.8
ฑ2.4
67.4
ฑ0.9
73.9
ฑ2.4
73.5
ฑ1.0
NA
NA
4.4
ฑ0.4
4.2
ฑ0.2
Winter Park, Florida - ORFL
Orlando Executive
Airport
12841
(28.55, -81.33)
3.95
miles
145ฐ
(SE)
Sample
Day
2011
82.2
ฑ2.4
82.8
ฑ0.9
72.9
ฑ2.3
73.0
ฑ0.9
62.4
ฑ2.5
62.1
ฑ1.0
66.4
ฑ2.2
66.3
ฑ0.9
72.1
ฑ2.2
71.3
ฑ1.0
1017.1
ฑ1.1
1017.4
ฑ0.4
6.1
ฑ0.6
5.8
ฑ0.2
VO
Sample day averages are highli;
NA= Sea level pressure was not
jhted to help differentiate the sample day averages from the full-year averages.
recorded at the Plant City Municipal Airport.
-------
Table 9-3. Average Meteorological Conditions near the Florida Monitoring Sites (Continued)
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Orlando, Florida - PAFL
Orlando Executive
Airport
12841
(28.55, -81.33)
0.84
miles
111ฐ
(ESE)
Sample
Day
2011
81.1
ฑ3.7
82.8
ฑ0.9
71.9
ฑ3.6
73.0
ฑ0.9
61.2
ฑ3.9
62.1
ฑ1.0
65.4
ฑ3.5
66.3
ฑ0.9
71.4
ฑ3.1
71.3
ฑ1.0
1017.9
ฑ1.5
1017.4
ฑ0.4
5.8
ฑ0.9
5.8
ฑ0.2
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
NA= Sea level pressure was not recorded at the Plant City Municipal Airport
-------
Table 9-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 9-3 is the
95 percent confidence interval for each parameter. As shown in Table 9-3, average
meteorological conditions on sample days in 2011 at the Florida monitoring sites were
representative of average weather conditions experienced throughout the entire year. The largest
difference is shown for PAFL and the temperature parameters. Sampling at PAFL took place on
a l-in-12 day schedule, yielding roughly half the sample days as the other Florida monitoring
sites. This may result in more variability in the sample day averages. Temperatures on sample
days at SYFL also appear slightly cooler than those for the entire year. SYFL did not deviate
from the l-in-6 day sample schedule until then end of the year, where make-up samples were
collected at SYFL in December, which may explain the differences shown in Table 9-3.
9.2.3 Back Trajectory Analysis
Figure 9-8 is the composite back trajectory map for days on which samples were
collected at the AZFL monitoring site in 2011. Included in Figure 9-8 are four back trajectories
per sample day. Figure 9-9 is the corresponding cluster analysis. Similarly, Figures 9-10 through
9-17 are the composite back trajectory maps and corresponding cluster analyses for the
remaining Florida monitoring sites. An in-depth description of these maps and how they
generated is presented in Section 3.5.2.1. For the composite maps, each line represents the
24-hour trajectory along which a parcel of air traveled toward the monitoring site on a given
sample day and time, based on an initial height of 50 meters AGL. For the cluster analyses, each
line corresponds to a trajectory representative of a given cluster of back trajectories. Each
concentric circle around the sites in Figures 9-8 through 9-17 represents 100 miles.
r were
9-16
-------
Figure 9-8. 2011 Composite Back Trajectory Map for AZFL
Figure 9-9. Back Trajectory Cluster Map for AZFL
9-17
-------
Figure 9-10. 2011 Composite Back Trajectory Map for SKFL
Figure 9-11. Back Trajectory Cluster Map for SKFL
9-18
-------
Figure 9-12. 2011 Composite Back Trajectory Map for SYFL
Figure 9-13. Back Trajectory Cluster Map for SYFL
9-19
-------
Figure 9-14. 2011 Composite Back Trajectory Map for ORFL
Figure 9-15. Back Trajectory Cluster Map for ORFL
9-20
-------
Figure 9-16. 2011 Composite Back Trajectory Map for PAFL
Figure 9-17. Back Trajectory Cluster Map for PAFL
'' ~A /
' - \
? / s -*
9-21
-------
Observations from Figures 9-8 through 9-13 for the Tampa/St. Petersburg sites include
the following:
The composite back trajectory maps for the Tampa/St. Petersburg sites are generally
similar to each other in trajectory distribution, which is not unexpected given their
close proximity to each other. Back trajectories originated from a variety of directions
at the Tampa/St. Petersburg sites.
The 24-hour air shed domains for these sites were comparable in size to other NMP
monitoring sites, with the average trajectory length ranging from 215 miles for AZFL
to 222 miles for SYFL. For AZFL and SKFL, the farthest away a back trajectory
originated was just greater than 500 miles away, originating eastward over the
Atlantic Ocean. For SYFL, the longest back trajectory originated over central North
Carolina, nearly 550 miles away. However, most trajectories (roughly 88 percent for
each site) originated within 400 miles of the Tampa/St. Petersburg monitoring sites.
The cluster maps for AZFL, SKFL, and SYFL are similar to each other in
geographical breakup, although the percentages differ somewhat. The cluster maps
for all three sites show that the approximately one-third or more of the back
trajectories are represented by the short cluster originating just west of the Tampa/St.
Petersburg area and over the Gulf of Mexico. This cluster includes back trajectories
of varying lengths originating to the west of the sites over the Gulf of Mexico as well
as shorter trajectories originating from a variety of directions around the sites.
The cluster maps group the remaining back trajectories into four directions:
northwestward over the Florida Panhandle, northeastward off the Southeast Coast,
eastward over the Atlantic Ocean, and southward over south Florida and the Straights
of Florida.
Observations from Figures 9-14 through 9-17 for ORFL and PAFL include the
following:
The composite back trajectory map for PAFL has fewer trajectories compared to the
map for ORFL. This is because sampling at PAFL occurred on a l-in-12 day
schedule, yielding approximately half the sample days as ORFL.
The 24-hour air shed domains were similar in size compared to the Tampa/
St. Petersburg monitoring sites. The longest trajectory originated northeastward over
the Atlantic Ocean for PAFL, or 560 miles away, with a few additional back
trajectories originating from a similar location. The longest back trajectory for ORFL
originated in southeast Virginia, nearly 650 miles away. PAFL does not have a
similar back trajectory because this site did not sample on this date.
Nearly 90 percent of back trajectories originated with 400 miles of ORFL and PAFL.
The cluster map for ORFL is similar to the cluster maps for the Tampa/St. Petersburg
sites in trajectory distribution. Nearly half of all back trajectories are represented by
the short cluster originating to the southwest of the site (44 percent). This cluster
9-22
-------
includes back trajectories originating from a variety of directions, although primarily
from the western quadrants, and less than 200 miles away. The cluster map groups
the remaining back trajectories into four directions: those originating northwestward
over the Florida Panhandle, Georgia, and Alabama; those originating northeastward
off the Southeast Coast; those originating eastward over the Atlantic Ocean and
northern Bahamas; and those originating southward over south Florida and the
surrounding waters.
The cluster map for PAFL has a short cluster (53 percent) similar to the one for
ORFL, but this cluster also includes those back trajectories originating from south
Florida (while the cluster map for ORFL separates them into a separate cluster).
The cluster map for PAFL groups the remaining back trajectories as follows:
northwestward over the Florida Panhandle, Georgia, and Alabama; northeastward off
the Southeast Coast, and east-southeastward over the Atlantic Ocean.
9.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations nearest the Florida sites, as
presented in Section 9.2.2, were uploaded into a wind rose software program to produce
customized wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind
directions using "petals" positioned around a 16-point compass, and uses different colors to
represent wind speeds.
Figure 9-18 presents a map showing the distance between the NWS station and AZFL,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 9-18 also presents three different wind roses for the
AZFL monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figures 9-19 through 9-22 present the three wind roses and
distance maps for SKFL, SYFL, ORFL, and PAFL, respectively.
9-23
-------
Figure 9-18. Wind Roses for the St. Petersburg/Whitted Airport Weather Station near
AZFL
Distance between AZFL and NWS Station
2001-2010 Historical Wind Rose
.,.*..- ;
ซ- s ;; :"*,","! . :
" '' 19* ปv.ป- f * ป
# ' " !
4-
2011 Wind Rose
Sample Day Wind Rose
9-24
-------
Figure 9-19. Wind Roses for the St. Petersburg/Clearwater International Airport Weather
Station near SKFL
Distance between SKFL and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
9-25
-------
Figure 9-20. Wind Roses for the Plant City Municipal Airport Weather Station near SYFL
Distance between SYFL and NWS Station
2008-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
9-26
-------
Figure 9-21. Wind Roses for the Orlando Executive Airport Weather Station near ORFL
Distance between ORFL and NWS Station
2001-2010 Historical Wind Rose
r ป^ To1 ! tUMIIIOt
t cc-sr,1
ฃ" Mivcinnst
2011 Wind Rose
Sample Day Wind Rose
WEST
WND SPEED
(Knots)
n -22
^| 17 - 21
^| 11 17
IH 7- 11
O 4-7
IB 2- 4
Calms: 14.89%
9-27
-------
Figure 9-22. Wind Roses for the Orlando Executive Airport Weather Station near PAFL
Distance between PAFL and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
9-28
-------
Observations from Figure 9-18 for AZFL include the following:
The NWS weather station at St. Petersburg/Whitted Airport is located approximately
6.8 miles east of AZFL. Between them is most of the city of St. Petersburg. Note that
the Whitted Airport is on the Tampa Bay coast while AZFL is on the west side of the
peninsula near the Boca Ciega Bay.
The historical wind rose shows that calm winds (< 2 knots) accounted for less than
10 percent of the hourly wind measurements. Winds from the north, northeasterly
quadrant, and east were the most commonly observed wind directions near AZFL
while winds from the western quadrants were observed less frequently.
The full-year wind rose shows that while winds from all directions were observed
near AZFL, winds from the north and east were the predominant wind directions,
similar to the historical wind rose.
The sample day wind patterns favor the full-year wind patterns, indicating that
conditions on sample days were representative of wind conditions experienced in
2011.
Both the full-year and sample day wind roses resemble the historical wind rose,
indicating that conditions on sample days and over the entire year were similar to
wind conditions experienced historically.
Observations from Figure 9-19 for SKFL include the following:
The NWS weather station at St. Petersburg/Clearwater Airport is located just less
than 4.5 miles north-northeast of SKFL. Note that the St. Petersburg/Clearwater
Airport is located on Old Tampa Bay while SKFL is farther inland.
The historical wind rose shows that winds from a variety of directions were observed
near SKFL, although winds from the north, northeast quadrant, east, and
east-southeast were the most commonly observed wind directions. Calm winds
accounted for approximately 10 percent of the hourly wind measurements.
The 2011 and sample day wind roses resemble the historical wind rose, indicating
that conditions on sample days and over the entire year were similar to wind
conditions experienced historically.
Observations from Figure 9-20 for SYFL include the following:
The NWS weather station at Plant City Municipal Airport is located 4.6 miles
northeast of SYFL. Note that this weather station has less historical data than the
other sites. This station did not begin operating until 2006 and data availability is
lacking until mid-2007; thus, the historical wind rose includes data from the first full-
year of data (2008) through 2010.
9-29
-------
The historical wind rose shows that calm winds (< 2 knots) account for approximately
25 percent of the hourly wind measurements between 2008 and 2010. Winds from the
eastern quadrants were observed more often than the western quadrants, although
winds from all directions were observed near SYFL.
Both the full-year and sample day wind patterns are similar to the historical wind
patterns, indicating that conditions on sample days were representative of wind
conditions experienced throughout the year and historically.
Observations from Figures 9-21 and 9-22 for ORFL and PAFL include the following:
The closest NWS weather station to both ORFL and PAFL is the Orlando Executive
Airport. The weather station is located just less than 4 miles southeast of ORFL and
less than 1 mile east-southeast of PAFL, as PAFL is located on the edge of the
Orlando Executive Airport property. Thus, the historical and full-year wind roses for
these sites are identical.
The historical wind roses show that winds from all directions were observed near
these sites, with easterly winds being observed the most, followed by winds from due
north and due south. Winds with an easterly component were observed more often
than winds with a westerly component. Calm winds were observed for less than 15
percent of the wind observations.
The wind patterns shown on the full-year wind roses resemble the wind patterns on
the historical wind roses.
The 2011 sample day wind rose for ORFL exhibits the same prominence of easterly,
northerly, and southerly winds, but winds from the southwest quadrant (and
northwest quadrant to some extent) account for a higher percentage of wind
observations than they do for the historical and full-year wind roses.
The 2011 sample day wind rose for PAFL shares the easterly prominence with the
2011 wind rose, but that is where the similarities in wind direction end. Winds from
the south and north account for fewer observations and winds from the east-northeast
account for more. Further, winds from the western quadrants account for more
observations than those from the eastern quadrants (with the exception of winds from
the east-northeast and east). Note, however, that PAFL samples on a l-in-12 day
sampling schedule, leading to roughly half the sample days included in the sample
day wind rose as ORFL.
9-30
-------
9.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Florida monitoring sites in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
For each site, each pollutant's preprocessed daily measurement was compared to its associated
risk screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by each monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 9-4 presents the results of the preliminary risk-based screening process for each
Florida monitoring site. The pollutants that failed at least one screen and contributed to 95
percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. AZFL and ORFL
sampled for carbonyl compounds only. SKFL and SYFL sampled hexavalent chromium and
PAHs in addition to carbonyl compounds. PAFL sampled only PMio metals.
Table 9-4. Risk-Based Screening Results for the Florida Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
St. Petersburg, Florida - AZFL
Formaldehyde
Acetaldehyde
0.077
0.45
Total
62
61
123
62
62
124
100.00
98.39
99.19
50.41
49.59
50.41
100.00
Pinellas Park, Florida - SKFL
Acetaldehyde
Formaldehyde
Naphthalene
Hexavalent Chromium
Propionaldehyde
0.45
0.077
0.029
0.000083
0.8
Total
61
61
52
1
1
176
61
61
61
55
61
299
100.00
100.00
85.25
1.82
1.64
58.86
34.66
34.66
29.55
0.57
0.57
34.66
69.32
98.86
99.43
100.00
9-31
-------
Table 9-4. Risk-Based Screening Results for the Florida Monitoring Sites (Continued)
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Plant City, Florida - SYFL
Formaldehyde
Acetaldehyde
Naphthalene
Acenaphthene
0.077
0.45
0.029
0.011
Total
60
57
37
2
156
60
60
60
60
240
100.00
95.00
61.67
3.33
65.00
38.46
36.54
23.72
1.28
38.46
75.00
98.72
100.00
Winter Park, Florida - ORFL
Acetaldehyde
Formaldehyde
0.45
0.077
Total
60
60
120
60
60
120
100.00
100.00
100.00
50.00
50.00
50.00
100.00
Orlando, Florida - PAFL
Arsenic (PM10)
0.00023
Total
28
28
31
31
90.32
90.32
100.00
100.00
Observations from Table 9-4 include the following:
Acetaldehyde and formaldehyde were the only two pollutants to fail screens for
AZFL and ORFL. Although these two pollutants contributed equally to the total
number of failed screens for ORFL, there was one more failed screen for
formaldehyde than acetaldehyde for AZFL. These two sites sampled only carbonyl
compounds; among the carbonyl compounds, only acetaldehyde, formaldehyde, and
propionaldehyde have risk screening values. Propionaldehyde did not fail any screens
for these two sites.
Five pollutants, of which four are NATTS MQO Core Analytes, failed screens for
SKFL. Acetaldehyde, formaldehyde, and naphthalene were identified as pollutants of
interest via the risk-based screening process. Hexavalent chromium was added to
SKFL's pollutants of interest because it is a NATTS MQO Core Analyte, even
though it did not contribute to 95 percent of SKFL's failed screens. Benzo(a)pyrene
was also added as a pollutant of interest for SKFL, even though it did not fail any
screens, because it is a NATTS MQO Core Analyte. Benzo(a)pyrene is not shown in
Table 9-4 but is shown in subsequent tables in the sections that follow.
Four pollutants, of which three are NATTS MQO Core Analytes, failed screens for
SYFL. Acetaldehyde, formaldehyde, and naphthalene were identified as pollutants of
interest via the risk-based screening process. Benzo(a)pyrene and hexavalent
chromium were added to SYFL's pollutants of interest because they are NATTS
MQO Core Analytes, even though their concentrations did not fail any screens. These
pollutants are not shown in Table 9-4 but are shown in subsequent tables in the
sections that follow.
Formaldehyde failed 100 percent of screens for all four sites sampling carbonyl
compounds.
9-32
-------
Arsenic was the only speciated metal to fail screens for PAFL. Ninety percent of the
measurements of arsenic failed screens. Five additional pollutants were added to
PAFL's pollutants of interest because they are NATTS MQO Core Analytes, even
though they did not fail any screens (beryllium, cadmium, lead, manganese, and
nickel). These pollutants are not shown in Table 9-4 but are shown in subsequent
tables in the sections that follow.
9.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Florida monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Florida monitoring sites, where the data meet the applicable
criteria. Concentration averages for select pollutants are also presented graphically for the sites to
illustrate how the sites' concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the sites. Additional site-
specific statistical summaries for the Florida monitoring sites are provided in Appendices L, M,
N,and O.
9.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Florida site, as described in Section 3.1. The quarterly average of a particular pollutant
is simply the average concentration of the preprocessed daily measurements over a given
calendar quarter. Quarterly average concentrations include the substitution of zeros for all non-
detects. A site must have a minimum of 75 percent valid samples of the total number of samples
possible within a given quarter for a quarterly average to be calculated. An annual average
includes all measured detections and substituted zeros for non-detects for the entire year of
sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Florida monitoring
sites are presented in Table 9-5, where applicable. Note that concentrations of the PAHs, metals,
and hexavalent chromium are presented in ng/m3 for ease of viewing. Also note that if a
pollutant was not detected in a given calendar quarter, the quarterly average simply reflects "0"
9-33
-------
because only zeros substituted for non-detects were factored into the quarterly average
concentration.
Table 9-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest
for the Florida Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Hg/m3)
2nd
Quarter
Average
(Hg/m3)
3rd
Quarter
Average
(jig/m3)
4th
Quarter
Average
(jig/m3)
Annual
Average
(jig/m3)
St. Petersburg, Florida - AZFL
Acetaldehyde
Formaldehyde
62/62
62/62
2.98
ฑ 0.59
1.69
ฑ 0.28
2.46
ฑ 0.67
1.86
ฑ 0.30
2.25
ฑ 0.49
1.81
ฑ 0.33
1.07
ฑ 0.16
2.03
ฑ 0.20
2.13
ฑ 0.30
1.86
ฑ 0.13
Pinellas Park, Florida - SKFL
Acetaldehyde
Formaldehyde
Benzo(a)pyrenea
Hexavalent Chromium3
Naphthalene3
61/61
61/61
55/61
55/62
61/61
3.15
ฑ 1.02
1.16
ฑ 0.31
0.05
ฑ 0.02
0.02
ฑ 0.01
83.83
ฑ 35.05
1.76
ฑ 0.24
2.72
ฑ 0.36
0.03
ฑ 0.01
0.03
ฑ 0.01
79.78
ฑ 25.27
1.58
ฑ 0.28
2.60
ฑ 0.31
0.04
ฑ 0.01
0.03
ฑ 0.01
99.97
ฑ 31.68
1.33
ฑ 0.19
2.13
ฑ 0.26
0.07
ฑ 0.05
0.01
ฑ 0.01
66.37
ฑ 24.19
1.95
ฑ 0.31
2.16
ฑ 0.21
0.05
ฑ 0.01
0.02
ฑ <0.01
82.22
ฑ 14.07
Plant City, Florida - SYFL
Acetaldehyde
Formaldehyde
Benzo(a)pyrene3
Hexavalent Chromium3
Naphthalene3
60/60
60/60
25/60
42/59
60/60
1.04
ฑ 0.18
1.62
ฑ 0.27
0.02
ฑ 0.01
0.01
ฑ 0.01
47.12
ฑ 15.91
1.34
ฑ 0.40
3.36
ฑ 0.97
0.02
ฑ 0.02
0.02
ฑ 0.01
46.58
ฑ 16.20
1.00
ฑ 0.25
2.75
ฑ 0.65
0.01
ฑ 0.01
0.02
ฑ 0.01
36.77
ฑ 9.75
0.75
ฑ 0.09
1.49
ฑ 0.20
0.05
ฑ 0.03
0.01
ฑ <0.01
38.20
ฑ 13.96
1.03
ฑ 0.13
2.30
ฑ 0.34
0.02
ฑ 0.01
0.01
ฑ <0.01
42.00
ฑ 6.68
Winter Park, Florida - ORFL
Acetaldehyde
Formaldehyde
60/60
60/60
1.82
ฑ 0.37
1.42
ฑ 0.28
2.08
ฑ 0.24
2.12
ฑ 0.30
1.81
ฑ 0.28
2.48
ฑ 0.36
1.67
ฑ 0.26
1.49
ฑ 0.25
1.85
ฑ 0.14
1.89
ฑ 0.18
3 Average concentrations provided below the blue line for this site and/or pollutant are presented in
ng/m3 for ease of viewing.
9-34
-------
Table 9-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest
for the Florida Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Orlando, Florida - PAFLa
Arsenic (PM10)a
Beryllium (PM10)a
Cadmium (PM10)a
Lead (PM10)a
Manganese (PM10)a
Nickel (PM10)a
31/31
31/31
31/31
31/31
31/31
31/31
0.63
ฑ 0.31
0.01
ฑ <0.01
0.07
ฑ 0.02
2.25
ฑ 1.04
1.83
ฑ0.47
0.63
ฑ 0.15
0.31
ฑ 0.07
0.01
ฑ <0.01
0.05
ฑ 0.01
2.07
ฑ 0.86
2.39
ฑ0.82
0.98
ฑ 0.32
0.79
ฑ 0.36
0.01
ฑ 0.01
0.05
ฑ 0.01
1.86
ฑ 0.74
2.74
ฑ0.78
0.77
ฑ 0.10
0.70
ฑ 0.47
0.01
ฑ 0.01
0.05
ฑ 0.03
2.35
ฑ 1.40
1.96
ฑ0.81
0.53
ฑ 0.07
0.62
ฑ 0.17
0.01
ฑ 0.01
0.06
ฑ 0.01
2.13
ฑ 0.47
2.23
ฑ0.35
0.72
ฑ 0.10
a Average concentrations provided below the blue line for this site and/or pollutant are presented in
ng/m3 for ease of viewing.
Observations from Table 9-5 include the following:
SYFL's annual average concentration of formaldehyde (2.30 ฑ 0.34 |ig/m3) is the
highest annual average concentration among the Florida sites. The annual average
concentration of formaldehyde is higher than the annual average acetaldehyde
concentration for both SKFL and SYFL; the annual average of acetaldehyde is higher
than formaldehyde for AZFL; and the annual averages for the two carbonyl
compounds were similar to each for ORFL.
The annual average concentrations of formaldehyde range from 1.89 ฑ 0.18 |ig/m3
(ORFL) to 2.30 ฑ 0.34 |ig/m3 (SYFL). The annual average concentrations of
acetaldehyde range from 1.03 ฑ 0.13 |ig/m3 (SYFL) to 2.13 ฑ 0.30 |ig/m3 (AZFL).
The first quarter acetaldehyde average for SKFL is greater than the other quarterly
average concentrations and has a relatively large confidence interval associated with
it. A review of the data shows that the maximum concentration of acetaldehyde
measured at SKFL was measured on February 14, 2011 (8.94 |ig/m3) and is more
than twice the next highest concentration measured at SKFL (4.33 |ig/m3 measured
on January 3, 2011). The nine highest concentrations of acetaldehyde were measured
at SKFL during the first quarter of 2011.
Concentrations of formaldehyde appear to be higher during the warmer months of the
year, as the second and third quarter formaldehyde averages for SYFL and ORFL are
greater than the other quarterly average concentrations. This trend appears to
continue at SKFL but the confidence intervals calculated for these averages indicate
that the difference among the quarterly averages is not statistically significant. This
trend is not shown for AZFL.
9-35
-------
As previously discussed, SKFL and SYFL both sampled hexavalent chromium and
PAHs in addition to carbonyl compounds. Hexavalent chromium, naphthalene, and
benzo(a)pyrene are all pollutants of interest for these two sites. The annual average
concentrations of these three pollutants are higher for SKFL than SYFL, particularly
for naphthalene.
For PAFL, manganese and lead have the highest annual average concentrations
among the PMio metals. These are the only two metals with annual average
concentrations greater than 1 ng/m3.
For PAFL, the first and fourth quarter lead averages have relatively large confidence
intervals associated with them. A review of the data shows that two highest
concentrations of lead were measured on December 29, 2011 (6.53 ng/m3) and
March 16, 2011 (5.16 ng/m3). All other measurements of lead are less than 4 ng/m3.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the Florida
sites from those tables include the following:
None of the Florida monitoring sites appear in Table 4-10 for carbonyl compounds or
Table 4-11 for PAHs.
SKFL has the eighth highest annual average concentration of hexavalent chromium
among NMP sites sampling this pollutant, as shown in Table 4-12.
Because only nine NMP sites sampled PMi0 metals, all nine sites appear in
Table 4-12. The annual average concentrations of the PMio metals for PAFL ranked
eighth or ninth with the exception of arsenic, which ranked fifth.
9.4.2 Concentration Comparison
In order to better illustrate how a site's annual concentration averages compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde and
formaldehyde were created for AZFL, SKFL, SYFL, and ORFL. Box plots were also created for
benzo(a)pyrene, hexavalent chromium, and naphthalene for SKFL and SYFL and for arsenic,
lead, and manganese for PAFL. Figures 9-23 through 9-30 overlay the sites' minimum, annual
average, and maximum concentrations onto the program-level minimum, first quartile, median,
average, third quartile, and maximum concentrations, as described in Section 3.5.3.
9-36
-------
Figure 9-23. Program vs. Site-Specific Average Acetaldehyde Concentrations
AZFL
5YFL
6 8
Concentration (
10
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
16
Figure 9-24. Program vs. Site-Specific Average Arsenic (PMio) Concentration
m
PiFL
3.5
1 1.5 2 2.5 3 3.5 4 4.5
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
9-37
-------
Figure 9-25. Program vs. Site-Specific Average Benzo(a)pyrene Concentrations
E
E
0.75 1 1.25
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 9-26. Program vs. Site-Specific Average Formaldehyde Concentrations
H-
ORFL
10
15
Concentration (|
20
25
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
o
3D
9-38
-------
Figure 9-27. Program vs. Site-Specific Average Hexavalent Chromium Concentrations
SKFL
:us
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 9-28. Program vs. Site-Specific Average Lead (PMio) Concentration
15 20
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 9-29. Program vs. Site-Specific Average Manganese (PMio) Concentration
li
; Program Max Concentration = 395 ng/m3
I
75 100 1Z5
Concentration (ng/m3J
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
9-39
-------
Figure 9-30. Program vs. Site-Specific Average Naphthalene Concentrations
Program Max Concentration =773 ng/ms
5YFL
i Program Max Concentration =773 ng/m3
50
100
153
200 250 300
Concentration (ng/m3)
4;:
450
5DD
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 9-23 through 9-30 include the following:
Figure 9-23 for acetaldehyde shows that the annual average concentration for AZFL is
the only one that is greater than the program-level average concentration among the
Florida sites, although the annual average for SKFL (1.95 |ig/m3) is just less than the
program-level average (2.00 |ig/m3). SKFL's maximum concentration is the fourth
highest acetaldehyde concentration measured among NMP sites sampling this pollutant.
There were no non-detects of acetaldehyde measured at the Florida sites or across the
program.
Figure 9-24 for arsenic shows that PAFL's annual average concentration is just greater
than the program-level average concentration. The maximum arsenic concentration
measured at PAFL is less than the maximum concentration measured among sites
sampling PMio metals. There were no non-detects of arsenic measured at PAFL, although
there were a few reported across the program.
Figure 9-25 presents the box plots for benzo(a)pyrene. Note that the program-level first
quartile for this pollutant is zero and is not visible on the box plots. The box plots show
that the annual average concentration for SKFL is slightly higher than the annual average
concentration for SYFL and that both annual average concentrations are less than the
program-level average concentration. The annual average for SYFL is also less than the
program-level median concentration. Figure 9-25 also shows that the maximum
concentrations measured at these sites are considerably less than the maximum
concentration measured across the program.
Figure 9-26 for formaldehyde shows that the annual average concentrations of
formaldehyde for AZFL, SKFL, SYFL, and ORFL are all less than the program-level
average concentration. There is little difference among the site-specific annual averages
of formaldehyde across the Florida sites (less than 0.45 |ig/m3 separates them). Note that
the range of formaldehyde concentrations measured at SYFL is roughly twice the range
measured at AZFL, SKFL, and ORFL.
9-40
-------
Figure 9-27 presents the box plots for hexavalent chromium, which was measured at
SKFL and SYFL. The annual average concentration for SKFL is similar to the program-
level average while the annual average for SYFL is less than the program-level average.
SYFL's annual average concentration is also less than the program-level median
concentration. The maximum concentrations measured at SKFL and SYFL are both less
than the maximum concentration measured among NMP sites sampling this pollutant.
Figure 9-28 for lead shows that PAFL's annual average concentration is less than both
the program-level average and median concentrations. The maximum lead concentration
measured at PAFL is considerably less than the maximum concentration measured
among NMP sites sampling PMio metals.
Figure 9-29 presents the box plot for manganese. Note that the program-level maximum
concentration (395 ng/m3) is not shown directly on the box plot because the scale of the
box plot would be too large to readily observe data points at the lower end of the
concentration range. Thus, the scale has been reduced to 200 |ig/m3. Figure 9-29 shows
that PAFL's annual average concentration is less than the program-level average, median,
and first quartile concentrations. The maximum manganese concentration measured at
PAFL is roughly equivalent to the program-level median concentration. This site has the
smallest range of manganese measurements among NMP sites sampling PMio metals.
Figure 9-30 presents the box plots for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plots as the scale
has been reduced to 500 ng/m3 in order to allow for the observation of data points at the
lower end of the concentration range. The box plots show that the annual average
concentration for SKFL is nearly twice the annual average concentration for SYFL.
SKFL's annual naphthalene concentration is just greater than the program-level average
concentration, although difficult to discern in Figure 9-30. The maximum concentration
measured at SKFL is more than 100 ng/m3 greater than the maximum concentration
measured at SYFL.
9-41
-------
9.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. AZFL, ORFL, SKFL, and SYFL have sampled carbonyl compounds as part of the
NMP for at least 5 consecutive years. Thus, Figures 9-31 through 9-38 present the annual
statistical metrics for acetaldehyde and formaldehyde for each of these sites. In addition, SYFL
has sampled hexavalent chromium since 2005; thus, Figure 9-39 presents the annual statistical
metrics for hexavalent chromium for SYFL. The statistical metrics presented for assessing trends
include the substitution of zeros for non-detects. Sampling for PAHs at SKFL and SYFL,
hexavalent chromium at SKFL, and PMio metals at PAFL began in 2008, which is less than the
5 consecutive year criteria; thus, the trends analysis was not conducted for the pollutants for
these methods.
Figure 9-31. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at AZFL
I5
I
I
I
T
-i-
W
-s-
i
..<
1
3
If
J
t
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:
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2001 2002 1003 1004 2005
1337 1008 2009 2010 2011
O 5th Percentile Minimum Median Maximum 0 95th Percentile
' Average
9-42
-------
Figure 9-32. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at AZFL
i
E -
.a 10
I
1
B
!
(
<
IS
1 i
n r
> ^ fy 1 rtn 1 JU
E JL
r-t-i _ *! **-.. -^ r-E-i
,_ Hr1 ^.. ^_ --..^ r
LjjJ L-P-1 L-2-1 ^f LaJ L^ i-a-i
01 2002 2003 2004 2DD5 2006 2007 2008 2009 2010 2011
Year
O 5th Percentile - Minimum Median Maximum 0 95th Percentile * Average
Figure 9-33. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at ORFL
I
e
.9
S
2007 2008
Year
* 5th Percentile - Minimum Median - Maximum 95th Percentile
Average
9-43
-------
Figure 9-34. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at ORFL
"1
a Iu
E
1
3 3
B
e
ฃ
< 6
[
^ta
-r
1004
*
>
^
L
2005
5th Percentile
[
MM
-ฃ-^
2006
Minimum
"
^^m
2D07
Year
Median
1
^
1 * 1
^ r*n J_
"^
r , ^
200S 2009 2010 2011
Maximum * 95th Percentile ..^.. Average
Figure 9-35. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at SKFL
I
e
.9
S
2008
Ysar
* 5th Percentile - Minimum Median - Maximum
95th Percentile
Averปi e
9-44
-------
Figure 9-36. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at SKFL
ฃ
E
a
i
a
s, 4 .
E 4
S
!
The max mum
2005 is 91.7 |ag/m3
j
T T
I T
I
' 1 " 1
'"ita^ ~^ T ^
T ^^^^^ ' ^^^^m ^^^^ "
1 ^ ^
J
1 +* ซ
2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
Figure 9-37. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at SYFL
2007 2008
Ysar
* 5th Percentile - Minimum Median - Maximum 95th Percentile
Average
9-45
-------
Figure 9-38. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at SYFL
"1
Concentration
ft
C
ฃ
<
[
41 r '
I 1
i T
r , 5-, | "-i _,_,
1 + -f
t ! ! ' a1 *~~^ L
2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
Figure 9-39. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at SYFL
_
ge Concentration (n
3 c
i <
4
*
1005
- Minimum
r r
r L
I
c
^"
2006 2007 2008 2009 2010 2011
Year
- Median - Maximum 95th Percentile SthPercentile * Average
9-46
-------
Observations from Figure 9-31 for acetaldehyde measurements at AZFL include the
following:
Carbonyl compounds have been measured at AZFL since 2001, making this site one
of the longest running UATMP sites.
The maximum acetaldehyde concentration was measured in 2010 (8.09 |ig/m3),
although a similar concentration was also measured in 2003 (8.00 |ig/m3).
The average and median acetaldehyde concentrations increased through 2004 then
began to decrease significantly. The average began to increase again in 2009. This
increase cannot be attributed to an outlier here or there because the trend continued
into 2010 and the all statistical metrics exhibited this increase. The 95th percentile
more than doubled from 2008 to 2009, as did the average concentration. Although a
decrease is shown for 2011, additional years of sampling are required to determine if
this decrease will continue.
With the exception of 2001, the minimum concentration for each year is greater than
zero. Only two non-detects of acetaldehyde have been reported since the onset of
carbonyl compound sampling (both in 2001).
Observations from Figure 9-32 for formaldehyde measurements at AZFL include the
following:
The maximum formaldehyde concentration was measured in 2001, after which the
highest concentration measured decreased by nearly half. The three highest
concentrations of formaldehyde (ranging from 9.30 |ig/m3 to 16.1 |ig/m3) were all
measured in 2001.
The average formaldehyde concentration decreased significantly from 2002 to 2003.
The decreasing trend continued through 2004, after which an increasing trend is
shown, which lasted through 2008. A second significant decrease is shown for 2009.
The trends shown for formaldehyde in Figure 9-32 are almost the opposite of the
trends shown for acetaldehyde in Figure 9-30.
The range of formaldehyde concentrations measured at AZFL is at a minimum for
2011.
The minimum concentration for each period is greater than zero. No non-detects of
formaldehyde have been reported since the onset of carbonyl compound sampling in
2001.
9-47
-------
Observations from Figure 9-33 for acetaldehyde measurements at ORFL include the
following:
Sampling for carbonyl compounds began at ORFL in April 2003. Because fewer than
85 percent of possible samples were collected in 2003, Figure 9-33 excludes data
from 2003.
The maximum acetaldehyde concentration was measured in 2006 (9.55 |ig/m3).
The average concentration was at a maximum in 2006. After 2006, the average
concentrations have varied from 1.45 |ig/m3 in 2010 to 1.85 |ig/m3 in 2011.
Even though the range of acetaldehyde concentrations measured at ORFL is at a
minimum for 2011, the average concentration is at a maximum for the period from
2007 to 2011 (as is the median concentration).
The minimum concentration for each period is greater than zero, indicating that no
non-detects of acetaldehyde have been reported for this pollutant.
Observations from Figure 9-34 for formaldehyde measurements at ORFL include the
following:
The maximum formaldehyde concentration was measured in 2007 (16.1 |ig/m3),
although concentrations greater than 10 |ig/m3 were also measured in 2005 and 2008.
Even with the relatively high concentrations measured in the middle years of
sampling, the average concentrations exhibit a steady decreasing trend. The median
concentrations have decreased as well, but exhibited an increase in 2009, followed by
additional decreases.
The range of formaldehyde concentrations is at a minimum for 2011, similar to
acetaldehyde.
The minimum concentration for each year is greater than zero, indicating that no non-
detects of formaldehyde have been reported for this pollutant.
Observations from Figure 9-35 for acetaldehyde measurements at SKFL include the
following:
Sampling for carbonyl compounds began at SKFL in July 2004. Because fewer than
85 percent of possible samples were collected in 2004, Figure 9-35 excludes data
from 2004.
The maximum acetaldehyde concentration shown was measured in
2010 (10.3 |ig/m3). The four highest concentrations of acetaldehyde were all
measured in 2010 and 2011.
9-48
-------
The average acetaldehyde concentration increased steadily between 2007 and 2010,
after which a significant decrease is shown for 2011. Additional sampling is needed
to see if this decrease continues.
The range of concentrations measured, as indicated by the minimum and maximum
concentrations as well as the 5th and 95th percentiles, increased from 2007 through
2010. Although the second highest concentration was measured at SKFL in 2011, the
95th percentile is significantly lower for 2011.
The minimum concentration for each year is greater than zero, indicating that no non-
detects of acetaldehyde have been reported for this pollutant.
Observations from Figure 9-36 for formaldehyde measurements at SKFL include the
following:
The maximum formaldehyde concentration was measured at SKFL on July 9, 2005
(91.7 |ig/m3). Note that for 2005, the average concentration is greater than the 95th
percentile, reflecting the effects that an outlier can have on statistical measurements.
All other concentrations measured at this site were less than 6 |ig/m3 for the years
shown.
The average and median concentrations exhibit a steady decreasing trend over the
years shown, with the exception of 2011.
The range of concentrations measured, as indicated by the minimum and maximum
concentrations as well as the 5th and 95th percentiles, decreased significantly for 2009
and 2010, then increased for 2011. Note that the median is greater than the average
concentration for 2011, which is unusual. This means that there is more variability in
the concentrations measured in 2011 than in 2010. For instance, the median
concentration for 2011 is greater than the maximum concentration measured for 2010,
which means that 50 percent of the concentrations measured in 2011 are greater than
the maximum concentration measured in 2010.
The minimum concentration for each period is greater than zero, indicating that no
non-detects of formaldehyde have been reported for this pollutant.
Observations from Figure 9-37 for acetaldehyde measurements at SYFL include the
following:
Carbonyl compounds have been measured at SYFL since January 2004.
The maximum acetaldehyde concentration was measured on January 18, 2007
(15.3 |ig/m3). The next highest concentration, also measured in 2007, is roughly half
as high (7.55 |ig/m3).
9-49
-------
With the exception of 2007, the average concentrations have fluctuated between
1.03 |ig/m3 (2011) and 1.60 |ig/m3 (2004).
All of the statistical parameters increased for 2007. Aside from the two
measurements of acetaldehyde discussed above, 2007 had the greatest number of
acetaldehyde concentrations greater than 3 |ig/m3 (16), while every other year of
sampling had three or less. Thus, it is not just the outliers driving this average
concentration.
Only one non-detect of acetaldehyde has been reported since the onset of carbonyl
compound sampling at SYFL.
Observations from Figure 9-38 for formaldehyde measurements at SYFL include the
following:
The maximum formaldehyde concentration measured at SYFL was measured in 2005
(32.5 |ig/m3) and was nearly twice the next highest concentration measured in 2008
(17.1 |ig/m3), although several measurements similar in magnitude to this one were
also measured in 2007. In all, eight formaldehyde concentrations greater than
10 |ig/m3 have been measured at SYFL.
The average formaldehyde concentration has fluctuated over the years, ranging from
1.58 |ig/m3 in 2006 to 3.19 |ig/m3 in 2007.
Similar to acetaldehyde, all of the statistical parameters exhibit an increase for 2007,
even though the maximum concentrations were not measured during this year. The
difference between the 5th and 95th percentiles for 2007 compared to the difference for
the remaining years show that the measurements were higher in 2007. The number of
formaldehyde concentrations greater than 5 |ig/m3 is highest for 2007 (seven), while
every other year of sampling had two or less.
The minimum concentration for each year is greater than zero. No non-detects of
formaldehyde have been reported since the onset of carbonyl compound sampling in
2004.
Observations from Figure 9-39 for hexavalent chromium measurements at SYFL include
the following:
Hexavalent chromium sampling at SYFL began in January 2005.
The maximum hexavalent chromium concentration measured at SYFL (0.134 ng/m3)
was measured on July 3, 2005 and is similar in magnitude to the next highest
concentrations, measured on July 4, 2006 (0.120 ng/m3) and March 17, 2005
(0.119 ng/m3). These are the only three measurements greater than 0.1 ng/m3.
9-50
-------
The average hexavalent chromium concentration has decreased significantly over the
years since the onset of sampling, reaching a minimum in 2009. This is the year with
the smallest range of concentrations measured. With the exception of the minimum
and fifth percentiles, all statistical parameters increased in 2010 and again in 2011.
For 2008 and 2009, the median concentration decreased to zero, indicating that at
least 50 percent of the measurements were non-detects. The percentage of non-detects
increased from 28 percent in 2006 to a maximum of 70 percent in 2009. The number
of non-detects decreased in 2010 (41 percent) and again in 2011 (17 percent). The
changes in the statistical parameters are at least partially attributable to the number of
non-detects (and thus, zeros) factored into the calculations.
9.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each Florida monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
9.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Florida monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
9.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Florida sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
9-51
-------
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 9-6, where applicable. Cancer risk approximations
are presented as probabilities while the noncancer hazard approximations are ratios and thus,
unitless values.
Table 9-6. Risk Approximations for the Florida Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(jig/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
St. Petersburg, Florida - AZFL
Acetaldehyde
Formaldehyde
0.0000022
0.000013
0.009
0.0098
62/62
62/62
2.13
ฑ 0.3
1.86
ฑ 0.13
4.70
24.15
0.24
0.19
Pinellas Park, Florida - SKFL
Acetaldehyde
Benzo(a)pyrene 3
Formaldehyde
Hexavalent Chromium3
Naphthalene3
0.0000022
0.00176
0.000013
0.012
0.000034
0.009
0.0098
0.0001
0.003
61/61
55/61
61/61
55/62
61/61
1.95
ฑ 0.31
<0.01
ฑ <0.01
2.16
ฑ 0.21
<0.01
ฑ 0.01
0.08
ฑ 0.01
4.29
0.08
28.09
0.28
2.80
0.22
0.22
0.01
0.03
Plant City, Florida - SYFL
Acetaldehyde
Benzo(a)pyrene 3
Formaldehyde
Hexavalent Chromium3
Naphthalene 3
0.0000022
0.00176
0.000013
0.012
0.000034
0.009
0.0098
0.0001
0.003
60/60
25/60
60/60
42/59
60/60
1.03
ฑ 0.13
O.01
ฑ O.01
2.30
ฑ 0.34
0.01
ฑ O.01
0.04
ฑ 0.01
2.26
0.04
29.84
0.16
1.43
0.11
0.23
O.01
0.01
Winter Park, Florida - ORFL
Acetaldehyde
Formaldehyde
0.0000022
0.000013
0.009
0.0098
60/60
60/60
1.85
ฑ 0.14
1.89
ฑ 0.18
4.06
24.60
0.21
0.19
= a Cancer URE or Noncancer RfC is not available.
3 For the annual average concentration of this pollutant in ng/m3, refer to Table 9-5.
9-52
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Table 9-6. Risk Approximations for the Florida Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Orlando, Florida - PAFL
Arsenic (PM10)a
Bery Ilium (PM10)a
Cadmium (PM10)a
Lead(PM10)a
Manganese (PM10)a
Nickel (PM10)a
0.0043
0.0024
0.0018
0.00048
0.000015
0.00002
0.00001
0.00015
0.00005
0.00009
31/31
31/31
31/31
31/31
31/31
31/31
<0.01
ฑ <0.01
<0.01
ฑ <0.01
<0.01
ฑ <0.01
<0.01
ฑ <0.01
<0.01
ฑ<0.01
<0.01
ฑ <0.01
2.66
0.01
0.10
0.35
0.04
O.01
0.01
0.01
0.04
0.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 9-5.
Observations for the Florida sites from Table 9-6 include the following:
Formaldehyde has the highest cancer risk approximations among the sites sampling
carbonyl compounds, ranging from 24.15 in-a-million (AZFL) to 29.84 in-a-million
(SYFL).
The cancer risk approximations for acetaldehyde are an order of magnitude less than
the cancer risk approximations for formaldehyde, ranging from 2.26 in-a-million
(SYFL) to 4.70 in-a-million (AZFL).
For the two sites sampling PAHs and hexavalent chromium in addition to carbonyl
compounds, naphthalene has the third highest cancer risk approximations for each
site, behind formaldehyde and acetaldehyde. Cancer risk approximations for
hexavalent chromium and benzo(a)pyrene are less than 1.0 in-a-million for both sites.
For PAFL, arsenic has the highest cancer risk approximation (2.66 in-a-million). The
cancer risk approximations are less than 1.0 in-a-million for the remaining metals,
where a cancer URE is available.
All of the noncancer hazard approximations for the site-specific pollutants of interest
are less than 1.0, indicating that no adverse health effects are expected from these
individual pollutants.
9-53
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9.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 9-7 and 9-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 9-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 9-6. Table 9-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 9-6.
The pollutants listed in Tables 9-7 and 9-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 9.3, AZFL and ORFL sampled for carbonyl compounds only; SKFL and SYFL sampled
hexavalent chromium and PAHs in addition to carbonyl compounds; and PAFL sampled only
PMio metals. In addition, the cancer risk and noncancer hazard approximations are limited to
those pollutants with enough data to meet the criteria for annual averages to be calculated. A
more in-depth discussion of this analysis is provided in Section 3.5.5.3. Similar to the cancer risk
and noncancer hazard approximations, this analysis may help policy-makers prioritize their air
monitoring activities.
9-54
-------
Table 9-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Florida Monitoring Sites
Top 10 Total Emissions for Pollutants
with Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
St. Petersburg, Florida (Pinellas County) - AZFL
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Nickel, PM
Tetrachloroethylene
430.92
261.69
214.09
118.05
59.55
26.34
10.63
3.58
2.82
0.84
Benzene
Formaldehyde
1,3 -Butadiene
Nickel, PM
Hexavalent Chromium, PM
Naphthalene
Ethylbenzene
Arsenic, PM
POM, Group 2b
Acetaldehyde
3.36E-03
2.78E-03
1.79E-03
1.35E-03
9.45E-04
8.96E-04
6.54E-04
4.13E-04
3.15E-04
2.60E-04
Formaldehyde
Acetaldehyde
24.15
4.70
Pinellas Park, Florida (Pinellas County) - SKFL
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Nickel, PM
Tetrachloroethylene
430.92
261.69
214.09
118.05
59.55
26.34
10.63
3.58
2.82
0.84
Benzene
Formaldehyde
1,3 -Butadiene
Nickel, PM
Hexavalent Chromium, PM
Naphthalene
Ethylbenzene
Arsenic, PM
POM, Group 2b
Acetaldehyde
3.36E-03
2.78E-03
1.79E-03
1.35E-03
9.45E-04
8.96E-04
6.54E-04
4.13E-04
3.15E-04
2.60E-04
Formaldehyde
Acetaldehyde
Naphthalene
Hexavalent Chromium
Benzo(a)pyrene
28.09
4.29
2.80
0.28
0.08
-------
Table 9-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Florida Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants
with Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Plant City, Florida (Hillsborough County) - SYFL
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
Methyl tert butyl ether
POM, Group 2b
Nickel, PM
545.24
339.12
333.41
174.74
77.10
37.70
11.51
8.62
5.02
2.88
Formaldehyde
Benzene
1,3 -Butadiene
Hexavalent Chromium, PM
Nickel, PM
Naphthalene
Arsenic, PM
Ethylbenzene
POM, Group 2b
Acetaldehyde
4.33E-03
4.25E-03
2.31E-03
1.44E-03
1.38E-03
1.28E-03
1.01E-03
8.48E-04
4.42E-04
3.84E-04
Formaldehyde
Acetaldehyde
Naphthalene
Hexavalent Chromium
Benzo(a)pyrene
29.84
2.26
1.43
0.16
0.04
Winter Park, Florida (Orange County) - ORFL
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Tetrachloroethylene
Propylene oxide
581.25
350.51
334.02
169.72
80.64
34.81
10.25
6.17
2.34
1.17
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
Ethylbenzene
Hexavalent Chromium, PM
POM, Group 2b
Acetaldehyde
POM, Group 3
Arsenic, PM
4.56E-03
4.53E-03
2.42E-03
1.18E-03
8.35E-04
6.86E-04
5.43E-04
3.73E-04
3.57E-04
2.84E-04
Formaldehyde
Acetaldehyde
24.60
4.06
-------
Table 9-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Florida Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants
with Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Orlando, Florida (Orange County) - PAFL
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Tetrachloroethylene
Propylene oxide
581.25
350.51
334.02
169.72
80.64
34.81
10.25
6.17
2.34
1.17
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
Ethylbenzene
Hexavalent Chromium, PM
POM, Group 2b
Acetaldehyde
POM, Group 3
Arsenic, PM
4.56E-03
4.53E-03
2.42E-03
1.18E-03
8.35E-04
6.86E-04
5.43E-04
3.73E-04
3.57E-04
2.84E-04
Arsenic
Nickel
Cadmium
Beryllium
2.66
0.35
0.10
0.01
-------
Table 9-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Florida Monitoring Sites
oo
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
St. Petersburg, Florida (Pinellas County) - AZFL
Toluene
Xylenes
Methanol
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Styrene
Ethylene glycol
1,374.54
1,035.91
540.89
430.92
353.10
261.69
214.09
118.05
113.79
73.16
Acrolein
Nickel, PM
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Xylenes
Manganese, PM
Naphthalene
Lead, PM
625,802.58
31,311.86
29,777.05
21,845.80
14,364.15
13,116.58
10,359.11
10,118.05
8,780.20
6,986.71
Acetaldehyde 0.24
Formaldehyde 0.19
Pinellas Park, Florida (Pinellas County) - SKFL
Toluene
Xylenes
Methanol
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Styrene
Ethylene glycol
1,374.54
1,035.91
540.89
430.92
353.10
261.69
214.09
118.05
113.79
73.16
Acrolein
Nickel, PM
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Xylenes
Manganese, PM
Naphthalene
Lead, PM
625,802.58
31,311.86
29,777.05
21,845.80
14,364.15
13,116.58
10,359.11
10,118.05
8,780.20
6,986.71
Formaldehyde 0.22
Acetaldehyde 0.22
Naphthalene 0.03
Hexavalent Chromium <0.01
-------
Table 9-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Florida Monitoring Sites (Continued)
VO
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Plant City, Florida (Hillsborough County) - SYFL
Toluene
Xylenes
Methanol
Benzene
Hexane
Cyanide Compounds, gas
Hydrochloric acid
Ethylbenzene
Formaldehyde
Acetaldehyde
1,643.63
1,310.35
688.28
545.24
438.64
428.19
350.01
339.12
333.41
174.74
Acrolein
Cyanide Compounds, gas
1,3 -Butadiene
Formaldehyde
Nickel, PM
Manganese, PM
Acetaldehyde
Benzene
Hydrochloric acid
Arsenic, PM
851,462.75
535,232.13
38,551.07
34,021.47
31,976.42
23,688.87
19,415.44
18,174.77
17,500.47
15,600.20
Formaldehyde
Acetaldehyde
Naphthalene
Hexavalent Chromium
Noncancer Hazard
Approximation
(HQ)
0.23
0.11
0.01
<0.01
Winter Park, Florida (Orange County) - ORFL
Toluene
Xylenes
Methanol
Benzene
Hexane
Formaldehyde
Ethylbenzene
Acetaldehyde
Styrene
Ethylene glycol
1,693.63
1,316.88
629.52
581.25
434.13
350.51
334.02
169.72
164.64
81.80
Acrolein
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Xylenes
Cyanide Compounds, gas
Naphthalene
Arsenic, PM
Lead, PM
870,786.72
40,319.80
35,765.86
19,374.99
18,857.75
13,168.77
12,178.13
11,604.18
4,404.23
3,678.02
Acetaldehyde
Formaldehyde
0.21
0.19
-------
Table 9-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Florida Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity- Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Orlando, Florida (Orange County) - PAFL
Toluene
Xylenes
Methanol
Benzene
Hexane
Formaldehyde
Ethylbenzene
Acetaldehyde
Styrene
Ethylene glycol
1,693.63
1,316.88
629.52
581.25
434.13
350.51
334.02
169.72
164.64
81.80
Acrolein
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Xylenes
Cyanide Compounds, gas
Naphthalene
Arsenic, PM
Lead, PM
870,786.72
40,319.80
35,765.86
19,374.99
18,857.75
13,168.77
12,178.13
11,604.18
4,404.23
3,678.02
Manganese
Arsenic
Lead
Nickel
Cadmium
Beryllium
0.04
0.04
0.01
0.01
0.01
<0.01
-------
Observations from Table 9-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Pinellas, Hillsborough, and Orange Counties, although not
necessarily in that order.
Benzene, formaldehyde, and 1,3-butadiene have the highest toxi city-weighted
emissions for all three counties, although the order varies.
Seven of the highest emitted pollutants in Hillsborough and Orange Counties also
have the highest toxi city-weighted emissions. Eight of the highest emitted pollutants
in Pinellas County also have the highest toxicity-weighted emissions.
Formaldehyde, which has the highest cancer risk approximations for all sites
sampling carbonyl compounds, is one of the highest emitted pollutants in each county
and has one of the highest toxicity-weighted emissions for each county. This is also
true for acetaldehyde.
PAFL sampled only PMio metals; arsenic has the highest cancer risk approximation
for this site. Arsenic ranks 10th among the toxicity-weighted emissions for Orange
County, but is not among the highest emitted pollutants, indicating the relative
toxicity of a low quantity of emissions.
Hexavalent chromium, which was sampled for at SKFL and SYFL, ranks between
fourth and sixth among each county's toxicity-weighted emissions but is not among
the highest emitted for any of the Florida counties.
POM, Group 2b is one of the highest emitted "pollutants" in all three counties and
appears among the pollutants with the highest toxicity-weighted emissions. POM,
Group 2b includes several PAHs sampled for at SKFL and SYFL including
acenaphthene, benzo(e)pyrene, and fluorene. None of these pollutants failed screens
for SKFL or SYFL.
Observations from Table 9-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in all three Florida counties.
Acrolein has the highest toxicity-weighted emissions of the pollutants with noncancer
RfCs for each county, but is not among the highest emitted pollutants in the three
Florida counties.
Four of the highest emitted pollutants in Pinellas and Orange Counties also have the
highest toxicity-weighted emissions. Five of the highest emitted pollutants in
Hillsborough County also have the highest toxicity-weighted emissions.
9-61
-------
Formaldehyde and acetaldehyde, which have the highest noncancer hazard
approximations for the sites sampling carbonyl compounds, appear on both
emissions-based lists for each site/county. Naphthalene is among the pollutants with
the highest toxicity-weighted emissions for Pinellas and Orange Counties but is not
among the highest emitted in any of the three counties. For PAFL, arsenic and lead
are among the pollutants with the highest toxicity-weighted emissions. None of the
metals sampled at PAFL are among the highest emitted pollutants in Orange County.
9.6 Summary of the 2011 Monitoring Data for the Florida Monitoring Sites
Results from several of the data treatments described in this section include the
following:
ปซป Acetaldehyde and'formaldehyde failedscreens for AZFL andORFL, where only
carbonyl compounds were sampled. Five pollutants (three carbonyls, naphthalene,
and hexavalent chromium) failed screens for SKFL. Four pollutants (two carbonyls
and two PAHs) failed screens for SYFL. Arsenic was the only PMw metal to fail
screens for PAFL.
ปซป Acetaldehyde had the highest annual average concentration for AZFL, formaldehyde
had the highest annual average concentration for SKFL and SYFL, and the annual
averages of these two pollutants were roughly the same for ORFL. Manganese and
lead had the highest annual average concentration of the metals sampled at PAFL.
ปซป Formaldehyde concentrations were higher during the warmer months of the year at
SYFL and ORFL.
ปซป Concentrations of formaldehyde have a decreasing trend at ORFL since the onset of
sampling. In recent years, concentrations of hexavalent chromium have been
increasing at SYFL. Concentrations of acetaldehyde decreased significantly between
2010 and 2011 at AZFL and SKFL. Conversely, formaldehyde concentrations at
SKFL have increased between 2010 and 2011.
9-62
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10.0 Site in Georgia
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Georgia, and integrates these concentrations with
emissions, meteorological, and risk information. Data generated by sources other than ERG are
not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
10.1 Site Characterization
This section characterizes the SDGA monitoring site by providing geographical and
physical information about the location of the site and the surrounding area. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
site and assist in the interpretation of the ambient monitoring measurements.
The SDGA monitoring site is located in Decatur, Georgia, a suburb of Atlanta. Figure 10-
1 is a composite satellite image retrieved from ArcGIS Explorer showing the monitoring site in
its urban location. Figure 10-2 identifies nearby point source emissions locations by source
category, as reported in the 2008 NEI for point sources. Note that only sources within 10 miles
of the site are included in the facility counts provided in Figure 10-2. A 10-mile boundary was
chosen to give the reader an indication of which emissions sources and emissions source
categories could potentially have a direct effect on the air quality at the monitoring site. Further,
this boundary provides both the proximity of emissions sources to the monitoring site as well as
the quantity of such sources within a given distance of the site. Sources outside the 10-mile
radius are still visible on the map, but have been grayed out in order to show emissions sources
just outside the boundary. Table 10-1 provides supplemental geographical information such as
land use, location setting, and locational coordinates.
10-1
-------
Figure 10-1. Decatur, Georgia (SDGA) Monitoring Site
-------
Figure 10-2. NEI Point Sources Located Within 10 Miles of SDGA
Legend
^ SDGA NATTS site
64'10'0*W
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
10 mile radius
County boundary
Source Category Group (No. of Facilities)
+ Aircraft Operations (22)
6 Bakery (1)
ฉ Fabricated Metal Products (1)
--- Flexible Polyurethane Foam Production (2)
F Food Processing/Agriculture (1)
V Glass Manufacturing (1)
ฎ Institutional-school (1)
Landfill (2)
? Miscellaneous Commercial/lndustrial (3)
Oil and/or Gas Production (1)
S Surface Coating (1)
10-3
-------
Table 10-1. Geographical Information for the Georgia Monitoring Site
Site
Code
SDGA
AQS Code
13-089-0002
Location
Decatur
County
DeKalb
Micro- or
Metropolitan
Statistical Area
Atlanta-Sandy
Springs-Marietta,
CrA
Latitude
and
Longitude
33.688007,
-84.290325
Land Use
Residential
Location
Setting
Suburban
Additional Ambient Monitoring Information1
CO, SO2, NOy, NO, NO2, NOX, PAMS, Carbonyl
compounds, VOCs, O3, Meteorological parameters,
PMio, PM Coarse, PM10 Speciation, Black carbon,
PM2 5, and PM2 5 Speciation, Haze.
BOLD ITALICS = EPA-designated NATTS Site
-------
SDGA is located on the DeKalb County Schools Environmental Education property off
Wildcat Road and is the South DeKalb NATTS site. Residential subdivisions, a greenhouse and
horse barn, an athletic field, and a high school surround the monitoring site. A golf course backs
up against the school property. Interstate-285 is located less than 1 mile north of the site, as
shown in Figure 10-1. As Figure 10-2 shows, only one point source (a bakery) is located in close
proximity to SDGA. Additional sources are located primarily on the west side of the 10-mile
radius. The aircraft operations source category (which includes airports as well as small runways,
heliports, or landing pads) is the source category with the greatest number of emissions sources
within 10 miles of SDGA.
Table 10-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Georgia monitoring site. Table 10-2 includes county-level
population and vehicle registration information. Table 10-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within DeKalb County. In addition, the population within 10 miles of the site is
presented, based on postal code population data estimates. An estimate of 10-mile vehicle
ownership was determined by applying the county-level vehicle registration-to-population ratio
to the 10-mile population surrounding the monitoring site. Table 10-2 also contains traffic
volume information for SDGA. Finally, Table 10-2 presents the county-level daily VMT for
DeKalb County.
Table 10-2. Population, Motor Vehicle, and Traffic Information for the Georgia
Monitoring Site
Site
SDGA
Estimated
County
Population1
699,893
County-level
Vehicle
Registration2
472,535
Vehicles per
Person
(Registration:
Population)
0.68
Population
within 10
miles3
730,133
Estimated
10-mile
Vehicle
Ownership
492,952
Annual
Average
Daily
Traffic4
140,820
County-
level Daily
VMT5
20,187,000
Bounty-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Georgia Department of Revenue (GA DOR,
2011)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the Georgia DOT (GA DOT, 201 la)
5County-level VMT reflects 2011 data for all public roads from the Georgia DOT (GA DOT, 201 Ib)
BOLD ITALICS = EPA-designated NATTS Site
10-5
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Observations from Table 10-2 include the following:
SDGA's county-level population and vehicle registration are in the middle of the
range compared to other counties with NMP sites. The same is also true for its
10-mile population and estimated vehicle ownership.
The vehicle-per-person ratio is among the lower ratios compared to other NMP sites.
The traffic volume experienced near SDGA ranks eighth highest compared to other
NMP monitoring sites. The traffic estimate provided is for 1-285, north of Clifton
Spring Road.
The daily VMT for DeKalb County is in the middle of the range among counties with
NMP sites (where VMT data were available).
10.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Georgia on sample days, as well as over the course of the year.
10.2.1 Climate Summary
Atlanta is the largest city in Georgia, and is located at the base of the Blue Ridge
Mountains. The Gulf of Mexico to the south is the major moisture source for weather systems
that move across the region. Both topographical features, in addition to the Atlantic Ocean to the
east, exert moderating influences on the area's climate, tempering cold air outbreaks from the
north as well as summer heat waves. Summers are warm and humid while winters are relatively
mild, although snow is not uncommon. The semi-permanent Bermuda High Pressure offshore
over the Atlantic Ocean is a dominant weather feature affecting the Atlanta area, which pulls
warm, moist air into the region. Precipitation is ample, although autumn is the driest season
(Bair, 1992 and GSCO, 1998).
10-6
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10.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station to SDGA is located at W. B.
Hartsfield/Atlanta International Airport (WBAN 13874). Additional information about the
Hartsfield weather station, such as the distance between the site and the weather station, is
provided in Table 10-3. These data were used to determine how meteorological conditions on
sample days vary from conditions experienced throughout the year.
Table 10-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 10-3 is the
95 percent confidence interval for each parameter. As shown in Table 10-3, average
meteorological conditions on sample days appear slightly cooler and drier than weather
conditions throughout the year. This is likely a result of a number of make-up samples collected
at SDGA in the month of December.
10.2.3 Back Trajectory Analysis
Figure 10-3 is the composite back trajectory map for days on which samples were
collected at the SDGA monitoring site in 2011. Included in Figure 10-3 are four back trajectories
per sample day. Figure 10-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 10-3 and 10-4 represents 100 miles.
10-7
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Table 10-3. Average Meteorological Conditions near the Georgia Monitoring Site
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Decatur, Georgia - SDGA
W.B.
Hartsfield/ Atlanta
Intl. Airport
13874
(33.64, -84.43)
8.18
miles
239ฐ
(WSW)
Sample
Day
2011
71.3
ฑ4.0
73.6
ฑ 1.6
61.7
ฑ3.8
63.9
ฑ1.6
47.2
ฑ3.9
49.5
ฑ 1.5
54.0
ฑ3.4
55.9
ฑ1.4
62.4
ฑ2.9
62.9
ฑ 1.3
1017.5
ฑ1.3
1017.2
ฑ0.6
7.4
ฑ0.7
7.0
ฑ0.3
1 Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
o
oo
-------
Figure 10-3. 2011 Composite Back Trajectory Map for SDGA
Figure 10-4. Back Trajectory Cluster Map for SDGA
10-9
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Observations from Figures 10-3 and 10-4 include the following:
The composite back trajectory map for SDGA looks like a pinwheel, indicating that
back trajectories originated from a variety of directions around SDGA.
Size-wise, the 24-hour air shed domain for SDGA is in the bottom-third compared to
other NMP monitoring sites. While the farthest away a trajectory originated was
central Missouri, or nearly 500 miles away, the average back trajectory length is
200 miles. Eighty-four percent of back trajectories originated within 300 miles of the
site. The longest trajectories tended to originate from the northwest and west, over
Indiana, Illinois, Missouri, and Arkansas.
The cluster analysis confirms that the longest trajectories originated from the
northwest and west while the shortest trajectories originated from the north, east, and
southwest. Over one-quarter of the back trajectories originated from the southwest
over Alabama and tended to be less than 200 miles in length. Another 25 percent of
trajectories originated from the north over Tennessee and North Carolina. Nearly
20 percent of back trajectories originated from the northwest over Kentucky, Illinois,
and Indiana. Fourteen percent originated to the east, nine percent originated to the
south over the Florida Panhandle, and six percent originated westward over Arkansas.
10.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Hartsfield International
Airport near SDGA were uploaded into a wind rose software program to produce customized
wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions
using "petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 10-5 presents a map showing the distance between the NWS station and SDGA,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 10-5 also presents three different wind roses for the
SDGA monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
to determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
10-10
-------
Figure 10-5. Wind Roses for the Hartsfield International Airport Weather Station
near SDGA
Distance between SDGA and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
10-11
-------
Observations from Figure 10-5 for SDGA include the following:
The NWS weather station at Hartsfield International Airport is the closest weather
station to SDGA. The weather station is located approximately 8.2 miles west-
southwest of SDGA.
The historical wind rose shows that winds from the west to north-northwest account
for nearly 40 percent of wind observations. Easterly winds were also common. Winds
from the northeast quadrant were rarely observed. Calm winds (< 2 knots) were
observed for less than 10 percent of the hourly wind measurements.
The wind patterns on both the full-year and sample day wind roses are similar to
those of the historical wind rose, although northwesterly winds account for a greater
percentage of wind observations on the sample day wind rose.
10.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for SDGA in order to allow
analysts and readers to focus on a subset of pollutants through the context of risk. Each
pollutant's preprocessed daily measurement was compared to its associated risk screening value.
If the concentration was greater than the risk screening value, then the concentration "failed the
screen." Pollutants of interest are those for which the individual pollutant's total failed screens
contribute to the top 95 percent of the site's total failed screens. In addition, if any of the NATTS
MQO Core Analytes measured by the monitoring site did not meet the pollutant of interest
criteria based on the preliminary risk-based screening, that pollutant was added to the list of site-
specific pollutants of interest. A more in-depth description of the risk-based screening process is
presented in Section 3.2.
Table 10-4 presents the results of the preliminary risk-based screening process for
SDGA. The pollutants that failed at least one screen and contributed to 95 percent of the total
failed screens for the monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. SDGA sampled for PAHs and hexavalent
chromium.
10-12
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Table 10-4. Risk-Based Screening Results for the Georgia Monitoring Site
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Decatur, Georgia - SDGA
Naphthalene
Acenaphthene
Fluorene
0.029
0.011
0.011
Total
54
1
1
56
61
61
61
183
88.52
1.64
1.64
30.60
96.43
1.79
1.79
96.43
98.21
100.00
Observations from Table 10-4 for SDGA include the following:
Naphthalene, acenaphthene, and fluorene failed screens. Naphthalene failed the
majority of the screens (roughly 96 percent), accounting for 54 of the 56 total failed
screens; the other two pollutants failed only one screen each.
Naphthalene was the only pollutant initially identified as a pollutant of interest based
on the risk-based screening process. Benzo(a)pyrene and hexavalent chromium were
added as pollutants of interest for SDGA because they are NATTS MQO Core
Analytes, even though they did not fail any screens. These pollutants are not shown in
Table 10-4 but are shown in subsequent tables in the sections that follow.
10.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Georgia monitoring site. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for SDGA, where the data meet the applicable criteria.
Concentration averages for select pollutants are also presented graphically to illustrate how the
site's concentrations compare to the program-level averages, as presented in Section 4.1. In
addition, concentration averages for select pollutants are presented from previous years of
sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for SDGA are provided in Appendices M and O.
10.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for SDGA, as described in Section 3.1. The quarterly average of a particular pollutant is simply
the average concentration of the preprocessed daily measurements over a given calendar quarter.
Quarterly average concentrations include the substitution of zeros for all non-detects. A site must
have a minimum of 75 percent valid samples of the total number of samples possible within a
10-13
-------
given quarter for a quarterly average to be calculated. An annual average includes all measured
detections and substituted zeros for non-detects for the entire year of sampling. Annual averages
were calculated for pollutants where three valid quarterly averages could be calculated and
where method completeness was greater than or equal to 85 percent, as presented in Section 2.4.
Quarterly and annual average concentrations for the Georgia monitoring site are presented in
Table 10-5, where applicable. Note that if a pollutant was not detected in a given calendar
quarter, the quarterly average simply reflects "0" because only zeros substituted for non-detects
were factored into the quarterly average concentration.
Table 10-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Georgia Monitoring Site
Pollutant
#of
Measured
Detections vs.
# of Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Decatur, Georgia - SDGA
Benzo(a)pyrene
Hexavalent Chromium
Naphthalene
27/61
47/61
61/61
0.09
ฑ0.05
0.02
ฑ0.01
86.71
ฑ31.86
<0.01
ฑ0.01
0.02
ฑ0.01
104.86
ฑ36.88
0.02
ฑ0.02
0.01
ฑ0.01
92.53
ฑ35.91
0.08
ฑ0.06
0.01
ฑ0.01
82.09
ฑ 27.64
0.05
ฑ0.02
0.01
ฑ0.01
90.82
ฑ15.61
Observations for SDGA from Table 10-5 include the following:
The annual average concentration of naphthalene is significantly higher than the
annual average concentrations of benzo(a)pyrene and hexavalent chromium.
Concentrations of naphthalene measured at SDGA range from 10.3 ng/m3 to
294 ng/m3. SDGA's annual average concentration of naphthalene ranks tenth highest
among NMP sites sampling this pollutant (as shown in Table 4-11).
The first and fourth quarter averages of benzo(a)pyrene are greater than the other
quarterly averages and have relatively large confidence intervals associated with
them. This pollutant was detected in less than half of the PAH samples collected (27
out of 61). All but one of the 10 highest concentrations of this pollutant (those
greater than 0.01 ng/m3) were measured in the first and fourth quarters of 2011.
Conversely, this pollutant was detected only once during the second quarter and four
times during the third quarter.
Hexavalent chromium concentrations span an order of magnitude, ranging from
0.0049 ng/m3 to 0.0382 ng/m3.
10-14
-------
10.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzo(a)pyrene,
hexavalent chromium, and naphthalene were created for SDGA. Figures 10-6 through 10-8
overlay the site's minimum, annual average, and maximum concentrations onto the program-
level minimum, first quartile, median, average, third quartile, and maximum concentrations, as
described in Section 3.5.3.
Figure 10-6. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
I
SDGA
3.25
0.5
0.75 1 1.25
Concentration (ng/mi)
1.5
1.75
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 10-7. Program vs. Site-Specific Average Hexavalent Chromium Concentration
0.15
Concentration (nฃ/m3)
Program: IstQuartile 2nd Quartile 3rd Quartile
Site: Site Average Site Minimum/Maximum
4th Quartile
Average
10-15
-------
Figure 10-8. Program vs. Site-Specific Average Naphthalene Concentration
SDGi
Program Max Concentration = 779 ng/m3
100
153
200 250 300
Concentration (ng/mi)
35:
453
555
Program
Site:
: IstQuartile
Site Average
O
2ndQuartile 3rd Quartile 4thQuartile AVE
Site Minimum/Maximum
rage
Observations from Figures 10-6 through 10-8 include the following:
Figure 10-6 is the box plot for benzo(a)pyrene. Note that the first quartile for this
pollutant is zero and is not visible on this box plot. This box plot shows that the
annual average concentration for SDGA is less than the program-level average
concentration but greater than the program-level median. Figure 10-6 also shows
that the maximum concentration measured at SDGA is less than the maximum
concentration measured across the program. Several non-detects of
benzo(a)pyrene were measured at SDGA.
Figure 10-7 is the box plot for hexavalent chromium. Figure 10-7 shows that the
annual average concentration of hexavalent chromium for SDGA is less than the
program-level average concentration. SDGA's annual average concentration is
also less than the program-level median concentration. The maximum
concentration measured at SDGA is significantly less than the program-level
maximum concentration, but greater than the program-level third quartile
concentration. Several non-detects of hexavalent chromium were measured at
SDGA.
Figure 10-8 is the box plot for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot
because the scale of the box plot would be too large to readily observe data points
at the lower end of the concentration range. Thus, the scale has been reduced to
500 ng/m3. Figure 10-8 shows that the annual average concentration of
naphthalene for SDGA is greater than the program-level average concentration.
The maximum naphthalene concentration measured at SDGA is less than the
program-level maximum concentration. There were no non-detects of naphthalene
measured at SDGA or across the program.
10-16
-------
10.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. SDGA has sampled hexavalent chromium under the NMP since 2005. Thus,
Figure 10-9 presents the annual statistical metrics for hexavalent chromium for SDGA. The
statistical metrics presented for assessing trends include the substitution of zeros for non-detects.
SDGA began sampling PAHs in 2007, but did not begin until April, which does not allow for the
completeness criteria specified in Section 3.5.4 to be met; thus, the trends analysis was not
conducted for the pollutants for these methods.
Figure 10-9. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at SDGA
1
Concentration
i
a""
e
st
r
* ^ 1
....^^H ^^
2006 2007 2008 2009 2010 2011
Year
SthPercentile Minimum Median Maximum 95th Percentile *" Average
Observations from Figure 10-9 include the following:
Although hexavalent chromium sampling began in 2005 at SDGA, sampling did
not begin until late February, which does not yield enough samples for the
statistical metrics to be calculated for 2005, based on the criteria specified in
Section 3.5.4. Thus, Figure 10-9 begins with 2006.
10-17
-------
Due to sampler issues, sampling for hexavalent chromium was discontinued from
September 2007 through May 2008; therefore, no statistical metrics are presented
for 2007 or 2008.
The maximum concentration measured for each year shown has decreased by an
order of magnitude (0.300 ng/m3 in 2006 to 0.0382 ng/m3 in 2011). Yet, the
difference between the 5th and 95th percentiles exhibits little change over the last
three years of sampling, indicating that the majority of the measurements fall
within roughly the same range, at least since 2009.
The difference between the median and average concentration for each year has
decreased, indicating decreasing variability within the measurements. For 2011,
the difference between these two statistical parameters is 0.00011 ng/m3.
The minimum, 5th percentile, and median concentrations for 2009 are all 0,
indicating that at least 50 percent of the measurements are non-detects; as a result,
zeros were substituted for more than half of the samples (for statistical purposes).
The number of non-detects began to decrease after 2009, down to 19 percent for
2010 and 14 percent for 2011.
10.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
SDGA monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations regarding
the various toxicity factors, time frames, and calculations associated with these risk-based
screenings.
10.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Gerogia monitoring site to the ATSDRMRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
10-18
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10.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for SDGA and where annual average concentrations could
be calculated, risk was examined by calculating cancer risk and noncancer hazard
approximations. These approximations can be used as risk estimates for cancer and noncancer
effects attributable to the pollutants of interest. Although the use of these approximations is
limited, they may help identify where policy-makers may want to shift or confirm their air-
monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer risk and
noncancer hazard approximations are calculated and what limitations are associated with them.
Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer hazard
approximations are presented in Table 10-6, where applicable. Cancer risk approximations are
presented as probabilities while the noncancer hazard approximations are ratios and thus, unitless
values.
Table 10-6. Risk Approximations for the Georgia Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Decatur, Georgia - SDGA
Benzo(a)pyrene
Hexavalent Chromium
Naphthalene
0.00176
0.012
0.000034
0.0001
0.003
27/61
47/61
61/61
0.05
ฑ0.02
0.01
ฑ<0.01
90.82
ฑ15.61
0.09
0.17
3.09
<0.01
0.03
= A Cancer URE or Noncancer RfC is not available
Observations for SDGA from Table 10-6 include the following:
Naphthalene was the only pollutant of interest for which the cancer risk
approximation was greater than 1.0 in-a-million (3.09 in-a-million).
Noncancer hazard approximations for naphthalene and hexavalent chromium were
less than 1.0, indicating that no adverse health effects are expected from these
individual pollutants. Benzo(a)pyrene does not have a noncancer RfC.
10-19
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10.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 10-7 and 10-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 10-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 10-6. Table 10-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from the annual averages
provided in Table 10-6.
The pollutants listed in Tables 10-7 and 10-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 10.3, SDGA sampled for PAHs and hexavalent chromium. In addition, the cancer risk
and noncancer hazard approximations are limited to those pollutants with enough data to meet
the criteria for annual averages to be calculated. A more in-depth discussion of this analysis is
provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this
analysis may help policy-makers prioritize their air monitoring activities.
10-20
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Table 10-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Georgia Monitoring Site
o
to
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Cancer Risk
Approximation
Pollutant (in-a-million)
Decatur, Georgia (DeKalb County) - SDGA
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group la
Methyl tert butyl ether
378.41
213.44
191.48
102.73
46.29
24.10
6.82
3.49
0.49
0.29
Benzene
Formaldehyde
1,3 -Butadiene
Naphthalene
Ethylbenzene
Hexavalent Chromium, PM
POM, Group 2b
Acetaldehyde
Arsenic, PM
POM, Group 5a
2.95E-03
2.49E-03
1.39E-03
8.19E-04
5.34E-04
3.82E-04
3.07E-04
2.26E-04
1.31E-04
1.01E-04
Naphthalene 3.09
Hexavalent Chromium 0.17
Benzo(a)pyrene 0.09
-------
Table 10-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Georgia Monitoring Site
to
to
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer
Hazard
Approximation
Pollutant (HQ)
Decatur, Georgia (DeKalb County) - SDGA
Toluene
Xylenes
Methanol
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
1,018.74
794.36
430.90
378.41
223.04
213.44
191.48
102.73
56.41
46.29
Acrolein
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Naphthalene
Xylenes
Lead, PM
2,4-Toluene diisocyanate
Arsenic, PM
576,341.15
23,142.89
19,539.04
12,613.63
11,414.67
8,033.73
7,943.60
4,023.67
2,140.67
2,029.50
Naphthalene 0.03
Hexavalent Chromium <0.01
-------
Observations from Table 10-7 include the following:
Benzene, ethylbenzene, and formaldehyde are the highest emitted pollutants with
cancer UREs in DeKalb County.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
cancer UREs) are benzene, formaldehyde, and 1,3-butadiene.
Seven of the highest emitted pollutants also have the highest toxi city-weighted
emissions for DeKalb County.
Naphthalene, which has the highest cancer risk approximation for SDGA, has the
fourth highest toxicity-weighted emissions and sixth highest emissions for DeKalb
County.
Hexavalent chromium ranks sixth highest for toxicity-weighted emissions, but is not
among the highest emitted pollutants in DeKalb County.
POM, Group 2b is the eighth highest emitted "pollutant" in DeKalb County and ranks
seventh for toxicity-weighted emissions. POM, Group 2b includes several PAHs
sampled for at SDGA including acenaphthene, benzo(e)pyrene, fluorene, and
perylene. Although acenaphthene and fluorene each failed a single screen, neither
pollutant was identified as a pollutant of interest for SDGA.
Benzo(a)pyrene is part of POM, Group 5a. POM, Group 5a ranks tenth for toxi city-
based emissions, but is not among the highest emitted pollutants in DeKalb County.
Observations from Table 10-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in DeKalb County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, 1,3-butadiene, and formaldehyde.
Five of the highest emitted pollutants in DeKalb County also have the highest
toxicity-weighted emissions.
While naphthalene is not one of the 10 highest emitted pollutants with a noncancer
RfC in DeKalb County, its toxicity-weighted emissions rank sixth. Hexavalent
chromium does not appear on either emissions-based list.
10-23
-------
10.6 Summary of the 2011 Monitoring Data for SDGA
Results from several of the data treatments described in this section include the
following:
ปซป Naphthalene, acenaphthene, andfluorene failed screens for SDGA, although
naphthalene accounted for the majority of failed screens.
*ป* Of the site-specific pollutants of the interest, naphthalene had the highest annual
average concentration for SDGA.
ปซป Benzo(a)pyrene concentrations were highest during the colder months of the year.
10-24
-------
11.0 Sites in Illinois
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS and UATMP sites in Illinois, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
11.1 Site Characterization
This section characterizes the Illinois monitoring sites by providing geographical and
physical information about the location of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
Both Illinois sites are located in northwestern suburbs of Greater Chicago, with NBIL
located in Northbrook and SPIL located in Schiller Park. Figures 11-1 and 11-2 are composite
satellite images retrieved from ArcGIS Explorer showing the monitoring sites in their urban
locations. Figure 11-3 identifies nearby point source emissions locations by source category, as
reported in the 2008 NEI for point sources. Note that only sources within 10 miles of the sites are
included in the facility counts provided in Figure 11-3. A 10-mile boundary was chosen to give
the reader an indication of which emissions sources and emissions source categories could
potentially have a direct effect on the air quality at the monitoring sites. Further, this boundary
provides both the proximity of emissions sources to the monitoring sites as well as the quantity
of such sources within a given distance of the sites. Sources outside the 10-mile radii are still
visible on the map, but have been grayed out in order to show emissions sources just outside the
boundary. Table 11-1 provides supplemental geographical information such as land use, location
setting, and locational coordinates.
11-1
-------
Figure 11-1. Northbrook, Illinois (NBIL) Monitoring Site
i^Wromoll ;W?
$r-?&!|> ;ฃv, 4\v ซ ?M5 r^-'-';, qjfoif-
63
-------
Figure 11-2. Schiller Park, Illinois (SPIL) Monitoring Site
-------
Figure 11-3. NEI Point Sources Located Within 10 Miles of NBIL and SPIL
tO'Q-W 86'5'Q-W 88 Q'Q-W $7J55'0~W S7-SO'D~W &J~4$'QrW a7'4Q"Q"W W'KQ'W 87'30'CrW
Legend
-,- - - *s
88'OTTW 87"55"CTW 87"50'D"W 87'45'CTW 97^0'0'W B7"35XTVV
Note: Due lo facility density and collocation, the total facilities
displayed may not represent all: facilities within the area of interest,
NBIL NATTS site
SPIL UATMP Site
Source Category Group (No. of Facilities)
::: AtwastvE Product Manufacturing (2)
;?-" Air-eondiliomngi'Rer'rfcjjeration (2)
Hh Aircraft Operations (32)
I Asphalt Pf Qcessingi'Roolmg Manufacturing (3)
0 Aulo Body Shop/Painters (3)
ffl Au1amobile>Tfuck Manufacturing (9)
0 Bakery <9)
r Brow&ry/DistilleryArVinery (1)
. : Bnck Manufacturing i Structural Clay (3)
f Building Construction (6)
B Bulk Tertninals/BulJc Plants {10}
C Chemical Manufacturing {20)
Concrete Batch Plant (20)
[XJ Crematory AnimaVHuman<12)
0 Dry Cleaning Facility (51)
6 Electrical Equipment (18)
f Electricity Generation via Combustion (6)
E Electroplating, Plating, Polishing Anodizing. & Coloring (58)
4 Engine Testing (2)
10 mile radius |_ J County boundary
M Mss-eeHaneous Manufacturing (86)
Oil andtorGas Production (1)
CD Pharmaceutical Manufacturing (8)
i Pipeline Compressor Station {1)
1 Primary Metal Production (24)
^ซ Printing. Coaling & Dyeing of Fabnc <1)
P Printino/Puatehmg [90)
B Pulp and Paper PlantWood Products (18)
R Rubber and Miscelianeaus Plashes Products (25)
2 Secondary Metal Processing <5)
> Solid Waste Disposal - Commercial/Institutional i' i
V S1eel Mill (9)
S Surface Coaling (41)
TT TBiecominunDcalwns (t9)
J U.-Ki so Mi i-j!
^^ Transportalion Equipment (9)
^ Transportalion and Marketing of Petroleum Products ()
I Wa-5tewate r Treatment {Q)
W Woodworh, Furniture. MillwonV & Wood Preserving (3)
<*> Fabricated Meial Products (53)
Cv> Flexible Polyurethane Foam Production (5|i
F Food Processifia'AgrKuhure (3S'|
[ _j Fumilure Planl (10)
jf Gaaoline;Diesel S?rvHe Stalcort iSi
V G'ass Manufacturing (3)
fV Heating Ewpment Msnufsetunng (2)
[J] hi>-.ji-.=il if.;.
^ Hot Mix A&phalt Plant (&>
-%: Industrial Macnmery and Equipment (33)
^ tnsbtulional - school (30)
I Iron and Steel Foundry (2)
^ Laboratory (1)
A Landfill*?)
|_ Latga Appliance Manufactufing 41)
X Mine/Ouarry (10>
^T Mineral Produced)
5 Miscellaneous Coating ManuFacluring (1)
? Miscellaneous Cwnmercia'JInduslnal [571
11-4
-------
Table 11-1. Geographical Information for the Illinois Monitoring Sites
Site
Code
NBIL
SPIL
AQS Code
17-031-4201
17-031-3103
Location
Northbrook
Schiller
Park
County
Cook
County
Cook
County
Micro- or
Metropolitan
Statistical Area
Chicago-Joliet-
Naperville, IL-IN-
WIMSA
(Chicago Div)
Chicago-Joliet-
Naperville, IL-IN-
WIMSA
(Chicago Div)
Latitude
and
Longitude
42.139996,
-87.799227
41.965193,
-87.876265
Land Use
Residential
Mobile
Location
Setting
Suburban
Suburban
Additional Ambient Monitoring Information1
TSP, TSP Metals, CO, Hg, SO2, NO, NO2, NOX, NH3,
PAMS, O3, Meteorological parameters, PM10, PM2.5,
PM2s Speciation.
TSP, TSP Metals, CO, NO, NO2, NOX, Meteorological
parameters, PM2 5.
BOLD ITALICS = EPA-designated NATTS Site
-------
NBIL is located on the property of the Northbrook Water Filtration Station. Figure 11-1
shows that NBIL is located off State Highway 68, Dundee Road, near Exit 30 on 1-94 (the clover
leaf of which is located on the lower right hand side of Figure 11-1). A railway runs north-south
in front of the water filtration station and intersects Dundee Readjust south of the monitoring
site. The surrounding area is classified as suburban and residential. Commercial, residential, and
forested areas are nearby, as well as a country club and golf course. The NBIL monitoring site is
the Chicago NATTS site.
SPIL is located on the eastern edge of the Chicago-O'Hare International Airport between
Mannheim Road and 1-294, just north of the toll plaza. The nearest runway is less than 1/2 mile
from the site. The surrounding area is classified as suburban and mobile. Commercial and
residential areas are nearby and a railyard is located to the east of 1-294.
NBIL and SPIL are located within approximately 12 miles of each other. Each site is
located within 10 miles of numerous point sources, although the quantity of emissions sources is
higher near SPIL than NBIL, as shown in Figure 11-3. The source categories with the largest
number of sources within 10 miles of the Illinois monitoring sites are printing and publishing;
fabricated metal products; electroplating, plating, polishing, anodizing, and coloring; and dry
cleaning. Few point sources are located within 2 miles of NBIL, with most of the sources located
farther west or south. The closest source to NBIL is plotted under the symbol for the site in
Figure 11-3; this source is a dry cleaning facility. Besides the airport, the closest point source to
SPIL is involved in electroplating, plating, polishing, anodizing, and coloring.
Table 11-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Illinois monitoring sites. Table 11-2 includes county-level
population and vehicle registration information. Table 11-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 11-2 also
contains traffic volume information for each site. Finally, Table 11-2 presents the county-level
daily VMT for Cook County.
11-6
-------
Table 11-2. Population, Motor Vehicle, and Traffic Information for the Illinois Monitoring
Sites
Site
NBIL
SPIL
Estimated
County
Population1
5,217,080
County-level
Vehicle
Registration2
2,072,399
Vehicles per
Person
(Registration:
Population)
0.40
Population
within 10
miles3
890,037
2,028,028
Estimated
10-mile
Vehicle
Ownership
353,553
805,601
Annual
Average
Daily
Traffic4
34,600
190,000
County-
level Daily
VMT5
86,863,779
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the IL Secretary of State (IL SOS, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2010 data for SPIL and 2011 data for NBIL from the Illinois DOT (IL DOT, 2010 and 201 la)
5County-level VMT reflects 2011 data from the Illinois DOT (IL DOT, 201 Ib)
BOLD ITALICS = EPA-designated NATTS Site
Observations from Table 11-2 include the following:
Cook County has the second highest county-level population (behind Los Angeles
County) and fourth highest county-level vehicle registration (behind Los Angeles
County, CA; Maricopa County, AZ; and Harris County, TX) compared to other
counties with NMP sites.
The vehicle-per-person ratio for these sites is the third lowest compared to other NMP
sites.
The 10-mile radius population and estimated vehicle ownership are much higher near
SPIL than NBIL.
SPIL experiences a higher annual average daily traffic volume than NBIL. SPIL's
traffic volume is the fourth highest among all NMP sites, behind ELNJ, CELA, and
SEW A, while the traffic volume for NBIL is in the middle of the range among NMP
sites. Traffic data for SPIL is provided for 1-294 at Lawrence Avenue; traffic data for
NBIL is for Dundee Road near the railroad crossing.
The Cook County daily VMT ranks third among counties with NMP sites, behind
only Los Angeles County, CA and Maricopa County, AZ (where VMT data were
available).
11.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Illinois on sample days, as well as over the course of the year.
11-7
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11.2.1 Climate Summary
Daily weather fluctuations are common for the Chicago area. The proximity of Chicago
to Lake Michigan offers moderating effects from the continental climate of the region. In the
summertime, afternoon lake breezes can cool the city when winds from the south and southwest
push temperatures upward. In the winter, the origin of an air mass determines the amount and
type of precipitation. The largest snowfalls tend to occur when cold air masses flow southward
over Lake Michigan, most of which does not freeze in winter. Wind speeds average around
10 miles per hour, but can be greater due to winds channeling between tall buildings downtown,
giving the city its nickname, "The Windy City" (Bair, 1992).
11.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather stations nearest these sites were
retrieved for 2011 (NCDC, 2011). The two closest weather stations are located at Palwaukee
Municipal Airport (near NBIL) and O'Hare International Airport (near SPIL), WBAN 04838 and
94846, respectively. Additional information about the Palwaukee and O'Hare weather stations,
such as the distance between the sites and the weather stations, is provided in Table 11-3. These
data were used to determine how meteorological conditions on sample days vary from conditions
experienced throughout the year.
Table 11-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 11-3 is the
95 percent confidence interval for each parameter. As shown in Table 11-3, temperatures on
sample days appear cooler than temperatures over the course of the year at both sites. For NBIL,
the difference may be attributable to make-up samples. More make-up samples were collected
during the first and fourth (and colder) quarters of the year compared to those collected during
the second and third (and warmer) quarters of the year. Only two make-up samples were
collected at SPIL, both during December.
11-8
-------
Table 11-3. Average Meteorological Conditions near the Illinois Monitoring Sites
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Northbrook, Illinois - NBIL
Palwaukee
Municipal
Airport
04838
(42.12, -87.91)
5.27
miles
250ฐ
(WSW)
Sample
Day
2011
57.0
ฑ5.0
58.7
ฑ2.1
49.4
ฑ4.6
51.0
ฑ2.0
38.7
ฑ4.4
40.5
ฑ1.9
44.3
ฑ4.1
45.9
ฑ1.8
68.8
ฑ2.4
69.4
ฑ1.1
1016.8
ฑ1.5
1015.9
ฑ0.7
6.5
ฑ0.7
6.5
ฑ0.3
Schiller Park, Illinois - SPIL
O'Hare
International
Airport
94846
(41.99, -87.91)
2.32
miles
303ฐ
(WNW)
Sample
Day
2011
57.3
ฑ5.4
58.5
ฑ2.2
49.6
ฑ5.0
50.9
ฑ2.0
39.3
ฑ4.5
40.7
ฑ1.9
44.5
ฑ4.4
45.8
ฑ1.8
70.0
ฑ2.7
70.4
ฑ1.2
1016.0
ฑ1.6
1015.4
ฑ0.7
8.2
ฑ0.9
8.2
ฑ0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
11.2.3 Back Trajectory Analysis
Figure 11-4 is the composite back trajectory map for days on which samples were
collected at the NBIL monitoring site in 2011. Included in Figure 11-4 are four back trajectories
per sample day. Figure 11-5 is the corresponding cluster analysis. Similarly, Figure 11-6 is the
composite back trajectory map for days on which samples were collected at SPIL and
Figure 11-7 is the corresponding cluster analysis. An in-depth description of these maps and how
they were generated is presented in Section 3.5.2.1. For the composite maps, each line represents
the 24-hour trajectory along which a parcel of air traveled toward the monitoring site on a given
sample day and time, based on an initial height of 50 meters AGL. For the cluster analyses, each
line corresponds to a trajectory representative of a given cluster of back trajectories. Each
concentric circle around the sites in Figures 11-4 through 11-7 represents 100 miles.
Figure 11-4. 2011 Composite Back Trajectory Map for NBIL
11-10
-------
Figure 11-5. Back Trajectory Cluster Map for NBIL
Figure 11-6. 2011 Composite Back Trajectory Map for SPIL
11-11
-------
Figure 11-7. Back Trajectory Cluster Map for SPIL
Observations from Figures 11-4 through 11-7 include the following:
The composite back trajectory maps for NBIL and SPIL are similar to each other in
back trajectory distribution, which is expected given their proximity to each other.
Back trajectories originated from a variety of directions at the sites, with the longest
trajectories originating from the northwest and north. The predominant direction of
trajectory origin appears to be from the northwest and north.
The 24-hour air shed domains for NBIL and SPIL were among the largest in size
compared to other NMP sites. The longest back trajectory for each site was greater
than 1,000 miles in length and originated over Montana. These two trajectories are
the longest back trajectories computed among NMP sites. However, the average back
trajectory length for these sites is approximately 270 miles and greater than
80 percent of back trajectories originated within 400 miles of the sites.
The cluster map for NBIL is similar to the cluster map for SPIL in geographical
distribution of the clusters but the percentage of trajectories representing each cluster
varies. Sixty-two percent of back trajectories originated from a direction with a
westerly component for each site. The trajectories originating over Iowa (or due west)
were grouped with trajectories originating from the northwest for NBIL and with
trajectories originating from the southwest for SPIL.
11-12
-------
Thirty-nine percent of back trajectories originated from a direction with an easterly
component for each site. For NBIL, all back trajectories originating from the north
and northeast are grouped together, regardless of the length of trajectory, and are
represented by the cluster trajectory over Lake Superior (16 percent). Back
trajectories originating from the east, southeast, and south were grouped together, as
represented by the short cluster originating over Indiana (23 percent). For SPIL, the
model grouped short trajectories with an easterly component together under the short
cluster trajectory originating from the east (32 percent), while grouping only the
longer trajectories from the north and northeast together under the longer cluster
trajectory originating to the northeast (7 percent).
11.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations at Palwaukee Municipal
Airport (for NBIL) and O'Hare International Airport (for SPIL) were uploaded into a wind rose
software program to produce customized wind roses, as described in Section 3.5.2.2. A wind
rose shows the frequency of wind directions using "petals" positioned around a 16-point
compass, and uses different colors to represent wind speeds.
Figure 11-8 presents a map showing the distance between the NWS station and NBIL,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 11-8 also presents three different wind roses for the
NBIL monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figure 11-9 presents the distance map and three wind roses
for SPIL.
11-13
-------
Figure 11-8. Wind Roses for the Palwaukee Municipal Airport Weather Station near NBIL
Distance between NBIL and NWS Station
2001-2010 Historical Wind Rose
X
^^X,
_ '
ซ-
vtKliJJBes <*ปnr& *c5ปaCiN Im
_ :
2011 Wind Rose
Sample Day Wind Rose
11-14
-------
Figure 11-9. Wind Roses for the O'Hare International Airport Weather Station near SPIL
Distance between SPIL and NWS Station
2001-2010 Historical Wind Rose
WEST;
2011 Wind Rose
Sample Day Wind Rose
11-15
-------
Observations from Figure 11-8 for NBIL include the following:
The Palwaukee Municipal Airport weather station is located approximately 5.3 miles
west-southwest of NBIL.
The historical wind rose shows that winds from a variety of directions were observed
near NBIL, although winds from the south, south-southwest, and west accounted for
one-quarter of wind observations. Winds from the east-southeast to south-southeast
were observed the least often. Calm winds (<2 knots) were observed for
approximately 15 percent of the hourly measurements.
The 2011 wind rose exhibits similar patterns in wind directions as the historical wind
rose, indicating that wind conditions in 2011 were similar to what is experienced
historically.
The sample day wind patterns generally resemble the full-year wind patterns,
although there were fewer westerly wind observations.
Observations from Figure 11-9 for SPIL include the following:
The O'Hare International Airport weather station is located 2.3 miles west-northwest
of SPIL. The bulk of the airport property lies between the weather station and the
monitoring site.
The historical wind rose for SPIL shows that winds from a variety of directions were
observed, although winds from the south to southwest to west account for the highest
percentage of observations (greater than 40 percent). Winds from these directions also
tended to be the strongest. Winds from the southeast quadrant were observed the
least. Calm winds (< 2 knots) were observed for less than 10 percent of the hourly
measurements.
The 2011 wind rose exhibits similar patterns in wind directions as the historical wind
rose, although fewer wind observations from the southwest to west appear to be
reflected in wind observations from the northeast quadrant.
The sample day wind patterns exhibit a more even distribution of wind observations,
with most directions accounting for five to seven percent of the wind observations
(with the exception of east-southeast and west-northwest).
11.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Illinois monitoring sites in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
For each site, each pollutant's preprocessed daily measurement was compared to its associated
risk screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
11-16
-------
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by each monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 11-4 presents the results of the preliminary risk-based screening process. The
pollutants that failed at least one screen and contributed to 95 percent of the total failed screens
for each monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus, pollutants of
interest are shaded and/or bolded. NBIL sampled for VOCs, carbonyl compounds, SNMOCs,
metals (PMi0), PAHs, and hexavalent chromium, and is one of only two NMP sites sampling for
all six pollutant groups. SPIL sampled for VOCs and carbonyl compounds only.
Table 11-4. Risk-Based Screening Results for the Illinois Monitoring Sites
Pollutant
Screening
Value
(Hg/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Northbrook, Illinois - NBIL
Formaldehyde
Acet aldehyde
Benzene
Carbon Tetrachloride
Naphthalene
Arsenic (PM10)
1,3-Butadiene
Acrylonitrile
Manganese (PM10)
Fluorene
Acenaphthene
1 ,2-Dichloroethane
Fluoranthene
Chloroform
Ethylbenzene
Dichloromethane
/>-Dichlorobenzene
Hexachloro- 1 , 3 -butadiene
Nickel (PM10)
Benzo(a)pyrene
Lead (PM10)
Trichloroethylene
0.077
0.45
0.13
0.17
0.029
0.00023
0.03
0.015
0.005
0.011
0.011
0.038
0.011
9.8
0.4
7.7
0.091
0.045
0.0021
0.00057
0.015
0.2
62
60
55
55
53
46
37
35
31
21
20
18
15
13
9
6
4
4
4
2
2
2
62
62
55
55
61
53
41
35
53
61
61
18
61
55
55
55
18
4
53
59
53
24
100.00
96.77
100.00
100.00
86.89
86.79
90.24
100.00
58.49
34.43
32.79
100.00
24.59
23.64
16.36
10.91
22.22
100.00
7.55
3.39
3.77
8.33
11.15
10.79
9.89
9.89
9.53
8.27
6.65
6.29
5.58
3.78
3.60
3.24
2.70
2.34
1.62
1.08
0.72
0.72
0.72
0.36
0.36
0.36
11.15
21.94
31.83
41.73
51.26
59.53
66.19
72.48
78.06
81.83
85.43
88.67
91.37
93.71
95.32
96.40
97.12
97.84
98.56
98.92
99.28
99.64
11-17
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Table 11-4. Risk-Based Screening Results for the Illinois Monitoring Sites (Continued)
Pollutant
1 , 1 ,2,2-Tetrachloroethane
Xylenes
Screening
Value
(Ug/m3)
0.017
10
Total
#of
Failed
Screens
1
1
556
#of
Measured
Detections
1
55
1110
%of
Screens
Failed
100.00
1.82
50.09
% of Total
Failures
0.18
0.18
Cumulative
%
Contribution
99.82
100.00
Schiller Park, Illinois - SPIL
Acet aldehyde
Formaldehyde
Benzene
Carbon Tetrachloride
1,3-Butadiene
Acrylonitrile
Trichloroethylene
p-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
1 , 1 ,2,2-Tetrachloroethane
Carbon Bisulfide
Chloromethylbenzene
1 ,2-Dibromoethane
Propionaldehyde
0.45
0.077
0.13
0.17
0.03
0.015
0.2
0.091
0.038
0.4
0.045
0.017
70
0.02
0.0017
0.8
Total
62
62
56
56
55
47
21
15
15
7
3
2
1
1
1
1
405
62
62
56
56
55
47
42
33
15
55
3
2
56
1
1
62
608
100.00
100.00
100.00
100.00
100.00
100.00
50.00
45.45
100.00
12.73
100.00
100.00
1.79
100.00
100.00
1.61
66.61
15.31
15.31
13.83
13.83
13.58
11.60
5.19
3.70
3.70
1.73
0.74
0.49
0.25
0.25
0.25
0.25
15.31
30.62
44.44
58.27
71.85
83.46
88.64
92.35
96.05
97.78
98.52
99.01
99.26
99.51
99.75
100.00
Observations from Table 11-4 include the following:
Twenty-four pollutants, including 13 NATTS MQO Core Analytes, failed screens for
NBIL. Approximately 50 percent of the measured detections of these pollutants failed
screens.
Based on the risk-based screening process, 15 pollutants, of which nine are NATTS
MQO Core Analytes, were identified as pollutants of interest for NBIL. Four
additional NATTS MQO Core Analytes (trichloroethylene, nickel, lead, and
benzo(a)pyrene) were added to the pollutants of interest for NBIL, even though they
did not contribute to 95 percent of the failed screens for NBIL. Five additional
pollutants were added to the pollutants of interest for NBIL because they are NATTS
MQO Core Analytes, even though they did not fail any screens (beryllium, cadmium,
hexavalent chromium, tetrachloroethylene, and vinyl chloride). These five pollutants
are not shown in Table 11-4 but are shown in subsequent tables in the sections that
follow.
Benzene, carbon tetrachloride, and formaldehyde were detected in every VOC or
carbonyl compound sample collected at NBIL and failed 100 percent of screens.
Additional pollutants also failed 100 percent of screens, but the detection rate was
lower (such as acrylonitrile and 1,2-dichloroethane).
11-18
-------
Sixteen pollutants, including six NATTS MQO Core Analytes, failed screens for
SPIL.
Based on the risk-based screening process, nine pollutants, of which six are NATTS
MQO Core Analytes, were identified as pollutants of interest for SPIL. Three
additional NATTS MQO Core Analytes were added to the pollutants of interest for
SPIL, even though they did not fail any screens (chloroform, tetrachloroethylene, and
vinyl chloride). These pollutants are not shown in Table 11-4 but are shown in
subsequent tables in the sections that follow.
Acetaldehyde, benzene, carbon tetrachloride, and formaldehyde were detected in
every VOC and carbonyl compound sample collected at SPIL and failed 100 percent
of their screens. Other pollutants also failed 100 percent of screens, but the detection
rate was lower.
Recall from Section 3.2 that if a pollutant was measured by both the TO-15 and
SNMOC methods at the same site, the TO-15 results were used for the risk-based
screening process. As NBIL sampled both VOCs (TO-15) and SNMOCs, the TO-15
results were used for the 12 pollutants these methods have in common.
11.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Illinois monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Illinois monitoring sites, where the data meet the applicable
criteria. Concentration averages for select pollutants are also presented graphically for the sites to
illustrate how the sites' concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the sites. Additional site-
specific statistical summaries for NBIL and SPIL are provided in Appendices J through O.
11.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Illinois site, as described in Section 3.1. The quarterly average of a particular pollutant
is simply the average concentration of the preprocessed daily measurements over a given
calendar quarter. Quarterly average concentrations include the substitution of zeros for all non-
detects. A site must have a minimum of 75 percent valid samples of the total number of samples
possible within a given quarter for a quarterly average to be calculated. An annual average
includes all measured detections and substituted zeros for non-detects for the entire year of
11-19
-------
sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Illinois monitoring
sites are presented in Table 11-5, where applicable. Note that concentrations of the PAHs,
metals, and hexavalent chromium for NBIL are presented in ng/m3 for ease of viewing. Also
note that if a pollutant was not detected in a given calendar quarter, the quarterly average simply
reflects "0" because only zeros substituted for non-detects were factored into the quarterly
average concentration.
Table 11-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest
for the Illinois Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Northbrook, Illinois - NBIL
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Acenaphthene a
Arsenic (PM10)a
62/62
35/55
55/55
41/55
55/55
55/55
18/55
55/55
62/62
53/55
24/55
8/55
61/61
53/53
1.00
ฑ0.25
0.14
ฑ0.05
0.99
ฑ0.56
0.29
ฑ0.39
0.56
ฑ0.05
2.51
ฑ 1.17
0.01
ฑ0.02
0.20
ฑ0.09
2.49
ฑ1.82
0.31
ฑ0.31
0.04
ฑ0.03
<0.01
ฑ<0.01
2.63
ฑ0.76
NA
1.08
ฑ0.32
0.21
ฑ0.04
0.55
ฑ0.10
0.03
ฑ0.02
0.64
ฑ0.06
12.41
ฑ4.97
0.01
ฑ0.02
0.45
ฑ0.41
2.04
ฑ0.95
0.57
ฑ0.28
0.04
ฑ0.04
<0.01
ฑ<0.01
10.73
ฑ5.57
0.68
ฑ0.29
1.60
ฑ0.35
NA
NA
NA
NA
NA
NA
NA
3.18
ฑ0.84
NA
NA
NA
29.14
ฑ9.26
0.80
ฑ0.29
1.87
ฑ0.52
0.01
ฑ0.03
0.69
ฑ0.16
0.08
ฑ0.04
0.69
ฑ0.06
3.79
ฑ4.46
0.07
ฑ0.02
0.26
ฑ0.08
2.39
ฑ1.10
0.18
ฑ0.06
0.04
ฑ0.03
<0.01
ฑ0.01
7.79
ฑ7.07
0.89
ฑ0.36
1.41
ฑ0.20
0.13
ฑ0.03
0.71
ฑ0.16
0.12
ฑ0.10
0.64
ฑ0.03
6.06
ฑ2.17
0.03
ฑ0.01
0.32
ฑ0.12
2.53
ฑ0.57
0.35
ฑ0.13
0.04
ฑ0.02
<0.01
ฑ<0.01
13.14
ฑ4.14
0.73
ฑ0.15
NA = Not available due to the criteria for calculating a quarterly and/or annual average
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
11-20
-------
Table 11-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest
for the Illinois Monitoring Sites (Continued)
Pollutant
Benzo(a)pyrene a
Bery Ilium (PM10)a
Cadmium (PM10)a
Fluoranthene a
Fluorene a
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
#of
Measured
Detections
vs. # of
Samples
59/61
51/53
53/53
61/61
61/61
50/61
53/53
53/53
61/61
53/53
1st
Quarter
Average
(Ug/m3)
0.21
ฑ0.10
NA
NA
2.02
ฑ0.56
2.94
ฑ0.64
0.02
ฑ0.01
NA
NA
48.33
ฑ 13.63
NA
2nd
Quarter
Average
(Ug/m3)
0.14
ฑ0.05
0.01
ฑO.01
0.13
ฑ0.06
6.94
ฑ3.46
10.94
ฑ5.95
0.02
ฑ0.01
2.95
ฑ1.31
8.73
ฑ5.52
54.35
ฑ 19.54
1.20
ฑ0.19
3rd
Quarter
Average
(Ug/m3)
0.08
ฑ0.02
O.01
ฑO.01
0.12
ฑ0.05
17.28
ฑ5.24
30.24
ฑ9.82
0.01
ฑO.01
3.44
ฑ1.34
7.66
ฑ2.70
157.13
ฑ45.66
1.35
ฑ0.47
4th
Quarter
Average
(Ug/m3)
0.16
ฑ0.07
0.01
ฑO.01
0.19
ฑ0.07
2.78
ฑ1.74
7.33
ฑ6.21
0.02
ฑ0.01
6.46
ฑ3.34
11.45
ฑ6.47
127.06
ฑ103.17
1.46
ฑ0.59
Annual
Average
(Ug/m3)
0.15
ฑ0.03
0.01
ฑO.01
0.14
ฑ0.03
7.59
ฑ2.29
13.46
ฑ4.25
0.02
ฑO.01
4.16
ฑ1.07
8.30
ฑ2.29
99.39
ฑ29.75
1.27
ฑ0.21
Schiller Park, Illinois - SPIL
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
62/62
47/56
56/56
55/56
56/56
38/56
33/56
15/56
62/62
53/56
42/56
6/56
5.29
ฑ2.04
0.95
ฑ0.19
0.77
ฑ0.11
0.13
ฑ0.04
0.50
ฑ0.04
0.05
ฑ0.02
0.04
ฑ0.04
0.01
ฑ0.01
3.89
ฑ1.13
0.29
ฑ0.22
0.15
ฑ0.15
0.01
ฑ0.01
2.26
ฑ0.51
0.83
ฑ0.14
0.82
ฑ0.25
0.15
ฑ0.07
0.60
ฑ0.05
0.11
ฑ0.04
0.08
ฑ0.06
0.04
ฑ0.03
3.16
ฑ0.97
0.32
ฑ0.21
0.67
ฑ0.52
0.01
ฑ0.01
2.38
ฑ0.40
0.85
ฑ0.11
0.78
ฑ0.18
0.15
ฑ0.06
0.60
ฑ0.02
0.10
ฑ0.05
0.07
ฑ0.04
0.01
ฑ0.02
3.80
ฑ0.80
0.25
ฑ0.07
0.39
ฑ0.31
0.01
ฑ0.01
1.95
ฑ0.66
0.46
ฑ0.29
1.02
ฑ0.35
0.20
ฑ0.09
0.64
ฑ0.05
0.10
ฑ0.07
0.10
ฑ0.08
0.03
ฑ0.02
2.35
ฑ0.74
0.36
ฑ0.12
1.28
ฑ1.44
0.01
ฑ0.01
2.94
ฑ0.61
0.77
ฑ0.11
0.85
ฑ0.12
0.16
ฑ0.03
0.58
ฑ0.02
0.09
ฑ0.02
0.07
ฑ0.03
0.02
ฑ0.01
3.29
ฑ0.46
0.31
ฑ0.08
0.64
ฑ0.41
0.01
ฑ0.01
NA = Not available due to the criteria for calculating a quarterly and/or annual average
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
11-21
-------
Observations for NBIL from Table 11-5 include the following:
The pollutants with the highest annual average concentrations by mass are chloroform
(6.06 ฑ 2.17 |ig/m3), formaldehyde (2.53 ฑ 0.57 |ig/m3), and acetaldehyde
(1.41 ฑ 0.20 |ig/m3). The annual average concentrations for the remaining pollutants
of interest were less than 1.00 |ig/m3.
Third quarter average concentrations could not be calculated for the VOCs because
fewer than 75 percent of samples were valid during this quarter. For this same reason,
first quarter average concentrations could not be calculated for the PMio metals.
The annual average concentration of chloroform for NBIL is unusually high
compared to other sites sampling this pollutant. The second quarter average is
considerably higher than the other available quarterly average concentrations and the
confidence interval associated with the fourth quarter average concentration is greater
than the quarterly average itself. These indicate that the measurements of chloroform
are highly variable and that outliers are likely present. Chloroform concentrations
range from 0.308 to 32.9 |ig/m3, with a median concentration of 2.05 |ig/m3. The
maximum concentration of chloroform was measured at NBIL on December 2, 2011
(32.9 |ig/m3), although a similar concentration was also measured June 26, 2011
(32.8 |ig/m3). These are the highest concentrations of chloroform measured across the
program and of the 12 concentrations greater than 10 |ig/m3 measured across the
program, 11 were measured at NBIL. Of the 63 measurements of chloroform greater
than 1 |ig/m3,44 were measured at NBIL (with 16 measured at DEMI, one at PXSS,
and two at S4MO). These findings are consistent with findings discussed in previous
NMP reports.
The first quarter average concentrations for both benzene and 1,3-butadiene are the
highest of the quarterly averages and have relatively large confidence intervals
compared to the other quarterly averages, particularly 1,3-butadiene. A review of the
data shows that the two highest concentrations of benzene and 1,3-butadiene were
measured on the first two sample dates in January. The maximum concentration of
benzene was measured on January 9, 2011 (4.51 |ig/m3) and the second highest
concentration was measured on January 3, 2011 (2.15 |ig/m3). The maximum
concentration of 1,3-butadiene was measured on January 9, 2011 (2.68 |ig/m3) and
the second highest concentration was measured on January 3, 2011 (1.21 |ig/m3).
NBIL's maximum 1,3-butadiene concentrations rank second and fourth among NMP
sites sampling this pollutant and are the only two 1,3-butadiene concentrations
measured at NBIL greater than 1 |ig/m3. For benzene, these two concentrations are
the only concentrations measured at NBIL greater than 2 |ig/m3 (and only four
benzene concentrations measured at NBIL are greater than 1 jig/m3).
The second quarter average concentration of ethylbenzene is roughly twice as high as
the other quarterly averages, where they could be calculated, and has a relatively
large confidence interval associated with it. The maximum ethylbenzene
concentration was measured on June 8, 2011 (3.20 |ig/m3) and is more than twice the
next highest concentration (1.18 |ig/m3, measured on August 25, 2011). All other
measurements of this pollutant are less than 1 |ig/m3. The third highest concentration
11-22
-------
of ethylbenzene was measured on January 9, 2011, the same day the highest
concentrations of benzene and 1,3-butadiene were measured.
The first quarter average concentration of tetrachloroethylene is equivalent to its
confidence interval, indicating that outliers may be affecting this quarterly average.
The confidence interval for the second quarter average is also relatively large
compared to the average itself. A review of the data shows that concentrations of
tetrachloroethylene range from 0.068 |ig/m3to 2.42 |ig/m3, with a median
concentration of 0.177 |ig/m3. The maximum concentration was measured on
March 16, 2011 (2.42 |ig/m3), although a similar concentration was also measured on
May 21, 2011 (2.18 |ig/m3). These two tetrachloroethylene measurements rank
second and third highest among all NMP sites sampling VOCs.
The third quarter average concentrations of acenaphthene, fluoranthene, and fluorene
were significantly higher than the other quarterly averages. The maximum
concentration of each of these pollutants was measured on July 5, 2011. The highest
concentrations of these pollutants were measured in June, July, August, and October.
The third and fourth quarter average concentrations of naphthalene were more than
twice the first and second quarterly averages. The highest concentrations of
naphthalene were measured in July, August, and October. The maximum naphthalene
concentration (799 ng/m3) was measured at NBIL on October 6, 2011, with the
second highest concentration (322 ng/m3) measured on the following sample day
(October 12, 2011). The concentration measured on October 6, 2011 is the maximum
naphthalene concentration measured across all NMP sites sampling PAHs.
Among the PMi0 metals, manganese has the highest annual average concentration
(8.30 ฑ 2.29 ng/m3). The quarterly average concentrations for most of the PMio
metals are highest for the fourth quarter, although the difference is not statistically
significant among the quarters for most of them. This is most notable for lead and
manganese. A review of the highest concentrations for each of the metals reveals that
some of the highest concentrations of the metals were measured in the sample
collected October 6, 2011.
Observations for SPIL from Table 11-5 include the following:
The pollutants with the highest annual average concentrations by mass are
formaldehyde (3.29 ฑ 0.46 |ig/m3) and acetaldehyde (2.94 ฑ 0.61 |ig/m3). These are
the only pollutants with annual average concentrations greater than 1 |ig/m3.
Concentrations of most of the pollutants of interest for SPIL did not vary significantly
across calendar quarters. However, a few quarterly averages do stand out, as
described below.
The first quarter average concentration of acetaldehyde is twice as high as the other
quarterly averages and has a relatively large confidence interval associated with it. A
review of the data shows that seven of the eight highest concentrations of
acetaldehyde (those greater than 5 |ig/m3) were measured during the first quarter of
2011, and ranged from 5.74 |ig/m3 (measured on January 21, 2011) to 14.5 |ig/m3
11-23
-------
(measured on January 9, 2011). The two highest concentrations of acetaldehyde
measured among NMP sites sampling carbonyl compounds were measured at SPIL
(14.5 |ig/m3andll.2|ig/m3).
The fourth quarter average concentration of trichloroethylene is higher than the other
quarters and all four quarterly averages of this pollutant have relatively large
confidence intervals associated with them. This indicates that the concentrations of
trichloroethylene are highly variable. A review of the data shows that the highest
trichloroethylene concentration was measured on October 12, 2011 (8.40 |ig/m3) and
is the highest trichloroethylene concentration measured among NMP sites sampling
VOCs. Of the 11 concentrations of trichloroethylene greater than 1 |ig/m3 across the
program, nine of these were measured at SPIL. The two highest concentrations
measured at SPIL (8.40 |ig/m3 and 7.22 |ig/m3) were both measured in October,
leading to the relatively high fourth quarter average concentration. Trichloroethylene
concentrations ranged from 0.0377 |ig/m3to 8.40 |ig/m3, with a median concentration
of 0.145 |ig/m3 and 14 non-detects.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for NBIL and
SPIL from those tables include the following:
NBIL and SPIL appear in Tables 4-9 through 4-12 a total of 27 times.
As shown in Table 4-9, NBIL's annual average concentration of chloroform is the
highest annual average among all NMP sites sampling this pollutant. Further, the
annual average concentration of chloroform for NBIL is nearly eight times higher
than the next highest annual average (calculated for DEMI). This finding is similar to
the findings in the 2010 NMP report, although the difference is significantly higher
for 2011. NBIL also has the highest annual average concentration of vinyl chloride,
even though it was only detected eight times.
SPIL has the highest annual average concentration of trichloroethylene, which is
seven times greater than the next highest annual average concentration of this
pollutant (calculated for ELNJ). This is also similar to the 2010 NMP report. SPIL
also has the highest annual average concentration of acrylonitrile.
SPIL has the second highest annual average concentration of acetaldehyde among
NMP sites sampling carbonyl compounds, as shown in Table 4-10, behind only
ELNJ.
NBIL has the highest annual average concentration of fluorene and second highest
annual average concentration of acenaphthene among NMP sites sampling PAHs, as
shown in Table 4-11. Even though the maximum naphthalene concentration across
the program was measured at NBIL, the annual average concentration of naphthalene
for NBIL ranks sixth.
11-24
-------
As shown in Table 4-12, the annual average concentrations for NBIL were among the
top five for all of the program-level PMio metal pollutants of interest. However, it is
important to note that only nine sites sampled PMio metals and have enough data for
annual averages to be calculated.
11.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde, benzene,
1,3-butadiene, and formaldehyde were created for both NBIL and SPIL. Box plots were also
created for arsenic, benzo(a)pyrene, hexavalent chromium, lead, manganese, and naphthalene for
NBIL. Figures 11-10 through 11-19 overlay the sites' minimum, annual average, and maximum
concentrations onto the program-level minimum, first quartile, median, average, third quartile,
and maximum concentrations, as described in Section 3.5.3.
Figure 11-10. Program vs. Site-Specific Average Acetaldehyde Concentrations
E
Concentration (^ig/m3)
Program: 1st Quartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site: Site Average Site Minimum/Maximum
11-25
-------
Figure 11-11. Program vs. Site-Specific Average Arsenic (PMio) Concentration
-H
2 2.5 3
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 11-12. Program vs. Site-Specific Average Benzene Concentrations
Program Max Concentration = 23.8 ng/m3
SPIL
4
Program Max Concentration = 23.8 ug/m3
4 5 6
Concentration (ug/mi)
10
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 11-13. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
E
NEIL
0.25
0.75 1 1.25
Concentration (ng/mi)
1.5
1.75
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
11-26
-------
Figure 11-14. Program vs. Site-Specific Average 1,3-Butadiene Concentrations
NEIL
II
IF
_,
Program Max Concentration = 9. 51 (jg/ms i
Program Max Concentration = 9.51
1.5
Concentration (^
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 11-15. Program vs. Site-Specific Average Formaldehyde Concentrations
E
id:
IS
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 11-16. Program vs. Site-Specific Average Hexavalent Chromium Concentration
0.15
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
11-27
-------
Figure 11-17. Program vs. Site-Specific Average Lead (PMi0) Concentration
NEIL
10
15 20
Concentration (ng/m3)
3D
35
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile SrdQuartile 4thQuartile Ave
n
Site Minimum/Maximum
rage
Figure 11-18. Program vs. Site-Specific Average Manganese (PMi0) Concentration
NEIL
; Program Max Concentration = 395 ng/m3
50
75
100
Concentration (ng/m3)
125
150
175
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
Figure 11-19. Program vs. Site-Specific Average Naphthalene Concentration
NEIL
i Program Max Concentration = 779 ng/m3
50
100
is;
200 Z50 300
Concentration (ng/m3)
350
453
555
Program
Site:
: IstQuartile
Site Average
O
2ndQuartile SrdQuartile 4thQuartile Ave
Site Minimum/Maximum
rage
Observations from Figures 11-10 through 11-19 include the following:
Figure 11-10 shows that the annual average acetaldehyde concentration for SPIL
is twice the annual average acetaldehyde concentration for NBIL. NBIL's annual
average is less than both the program-level average and median concentrations
while the annual average for SPIL is greater than the program-level average and
third quartile. As discussed in the previous section, the two maximum
acetaldehyde concentrations measured among NMP sites sampling this pollutant
were measured at SPIL. There were no non-detects of acetaldehyde measured at
either site or across the program.
11-28
-------
Figure 11-11 is the box plot for arsenic, which was measured at NBIL but not at
SPIL. The box plot shows that the annual average concentration for NBIL is
greater than the program-level average concentration but just less than the
program-level third quartile. The maximum concentration measured at NBIL is
less than the maximum concentration measured across the program. While a few
non-detects of arsenic were measured among sites sampling PMio metals, none
were measured at NBIL.
Figure 11-12 shows the box plots for benzene. Note that the program-level
maximum concentration (23.8 |ig/m3) is not shown directly on the box plots
because the scale of the box plots would be too large to readily observe data
points at the lower end of the concentration range. Thus, the scale has been
reduced to 10 |ig/m3. Figure 11-12 shows that while SPIL's annual average
benzene concentration is greater than NBIL's annual average benzene
concentration, the range of measurements is larger for NBIL than SPIL. However,
both annual averages are less than the program-level average concentration. There
were no non-detects of benzene measured at either site or across the program.
Figure 11-13 is the box plot for benzo(a)pyrene. Note that the program-level first
quartile for this pollutant is zero and is not visible on this box plot. This box plot
shows that the annual average benzo(a)pyrene concentration for NBIL is greater
than the program-level average concentration and third quartile. Figure 11-13 also
shows that the maximum concentration measured at NBIL is less than the
maximum concentration measured across the program. Two non-detects of
benzo(a)pyrene were measured at NBIL.
Similar to the benzene graph, the program-level maximum 1,3-butadiene
concentration (9.51 |ig/m3) is not shown directly on the box plots as the scale has
been reduced to 3 |ig/m3 in Figure 11-14 to allow for the observation of data
points at the lower end of the concentration range. Figure 11-14 shows that both
sites' annual average 1,3-butadiene concentrations are greater than the program-
level average and, although difficult to discern in Figure 11-14, the program-level
third quartile. As discussed in the previous section, the maximum 1,3-butadiene
concentration for NBIL is the second highest among NMP sites sampling this
pollutant. A single non-detect of 1,3-butadiene was measured at SPIL while
14 non-detects were measured at NBIL.
Figure 11-15 presents the box plots for formaldehyde. The box plots show that
NBIL's annual average formaldehyde concentration is less than the program-level
average while SPIL's annual average formaldehyde concentration is greater than
the program-level average concentration. Figure 11-15 also shows that the range
of concentrations measured is larger for NBIL than SPIL. There were no non-
detects of formaldehyde measured at either site or across the program.
11-29
-------
Figure 11-16 shows that the annual average concentration of hexavalent
chromium for NBIL is less than the program-level average and median
concentrations. The maximum concentration measured at NBIL is less than the
program-level maximum concentration. There were several non-detects of
hexavalent chromium measured at NBIL and across the program.
Figure 11-17 is the box plot for lead, which was measured at NBIL only. The box
plot shows that the annual average concentration of lead for NBIL is greater than
the program-level average but less than the program-level third quartile. While the
maximum lead concentration measured at NBIL is less than the maximum
concentration measured across the program, it was the sixth highest measurement
of lead among NMP sites sampling PMio metals. There were no non-detects of
lead measured at NBIL or across the program.
Figure 11-18 is the box plot for manganese (PMio). Note that the program-level
maximum concentration (395 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 200 ng/m3 to allow for the observation of data points at
the lower end of the concentration range. The box plot shows that the annual
average concentration for NBIL is just less than the program-level average
concentration. The maximum concentration measured at NBIL is considerably
less than the maximum measured across the program. Although difficult to
discern in Figure 11-18, there were no non-detects of manganese measured at
NBIL or across the program.
Figure 11-19 is the box plot for naphthalene. The program-level maximum
concentration (779 ng/m3) is not shown directly on the box plot as the scale has
been reduced to 500 ng/m3 in order to allow for the observations of data points at
the lower end of the concentration range. Figure 11-19 shows that the maximum
concentration of naphthalene measured at NBIL is off the scale of the box plot;
this measurement is the maximum naphthalene concentration measured among all
NMP sites sampling this pollutant. The annual average concentration for NBIL is
greater than the program-level average concentration but less than the program-
level third quartile. There were no non-detects of naphthalene measured at NBIL
or across the program.
11-30
-------
11.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. NBIL and SPIL have sampled VOCs under the NMP since 2003. Both sites have
also sampled carbonyl compounds since 2005. Additionally, NBIL has sampled PMio metals and
hexavalent chromium since 2005. Figures 11-20 through 11-27 present the annual statistical
metrics for acetaldehyde, arsenic, benzene, 1,3-butadiene, formaldehyde, hexavalent chromium,
lead, and manganese for NBIL, respectively. Figures 11-28 through 11-31 present the annual
statistical metrics for acetaldehyde, benzene, 1,3-butadiene, and formaldehyde for SPIL,
respectively. The statistical metrics presented for assessing trends include the substitution of
zeros for non-detects. NBIL began sampling PAHs under the NMP in 2008, which is less than
5 consecutive years; therefore, the trends analysis was not conducted for the PAHs.
Figure 11-20. Annual Statistical Metrics for Acetaldehyde Concentrations Measured at
NBIL
2008 2009
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
11-31
-------
Figure 11-21. Annual Statistical Metrics for Arsenic (PMi0) Concentrations Measured at
NBIL
a
1 2
I
3
I.
2008 2009
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
Figure 11-22. Annual Statistical Metrics for Benzene Concentrations Measured at NBIL
Bth Percentile Minimum Median Maximum 95th Percentile ..^.. Average
11-32
-------
Figure 11-23. Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at
NBIL
Minimum Median - Maximurr
95th Percentile
. Average
Figure 11-24. Annual Statistical Metrics for Formaldehyde Concentrations Measured at
NBIL
I
e
.9
B
The maximum
concentration for
2006 is 91.7 Ug/m3
* 5th Percentile - Minimum Median - Maximum # 95th Percentile ..+.. Average
11-33
-------
.Figure 11-25. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at NBIL
Minimum Median - Maximun
95th Percentile
5th Percentile "^"Average
Figure 11-26. Annual Statistical Metrics for Lead (PMio) Concentrations Measured at
NBIL
a
S 15
s
i
zoos
Year
* 5th Percentile - Minimum Median - Maximum
95th Percentile
Average
11-34
-------
Figure 11-27. Annual Statistical Metrics for Manganese (PMi0) Concentrations Measured
at NBIL
2008
Year
5th Percentile Minimum Median Maximum
95th Percentile
. Average
Figure 11-28. Annual Statistical Metrics for Acetaldehyde Concentrations Measured at
SPIL
r
e
.9
B
ซ 8
s
i
I.
2003 2009
Year
* 5th Percentile - Minimum Median - Maximum 95th Percentile * Average
11-35
-------
Figure 11-29. Annual Statistical Metrics for Benzene Concentrations Measured at SPIL
tration (ug/m3)
Average Co noen
1 -
4
r
r f T 1
1 r
^ 1
*-.. . ,
*^ -^^ ^^.. ฃ " ^^
c i ^ r t
2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Max mum 95th Percentile ..+** Average
Figure 11-30. Annual Statistical Metrics for 1,3-Butadiene Concentrations Measured at
SPIL
L
Concentration
3 i
Tt i
1
-*
2004
iii
r
i l-n T r * *
i ฐ^ ' T
^^ I
ซ 1 1 _._
F btd r ^ I r
2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile ..^.. Average
11-36
-------
Figure 11-31. Annual Statistical Metrics for Formaldehyde Concentrations Measured at
SPIL
90 -
so -
70 -
m"
|5o-
J
50 -
1
a
| 40 -
<
30 -
20 -
10 -
0
The maximum |
rnnrpntratinnfnr !
2006 is 162 ug/mS. |
*...
""[^fa i i^^ 1 ^ |
^^m " l^^" , l^*" , l^^* . ]^^m
2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
Observations from Figure 11-20 for acetaldehyde measurements at NBIL include the
following:
Although carbonyl compound sampling at NBIL began in 2005, sampling did not
begin until March, which does not yield enough samples for the statistical metrics to
be calculated for 2005, based on the criteria specified in Section 3.5.4. Thus,
Figure 11-20 begins with 2006.
The maximum acetaldehyde concentration (4.12 |ig/m3) was measured in 2011, as
was the second highest concentration (3.47 |ig/m3). In fact, of the 19 acetaldehyde
concentrations greater than 2 |ig/m3 measured at NBIL, 11 were measured in 2011.
All of the statistical metrics exhibit an increase from 2009 to 2010 and again for
2011. The 95th percentile for 2011 is greater than the maximum concentration
measured for most years of sampling.
The difference between the average and median concentrations is at a maximum for
2011, reflecting greater variability in the acetaldehyde measurements.
The minimum concentration for each year is greater than zero, indicating that there
were no non-detects of acetaldehyde reported for the years shown.
11-37
-------
Observations from Figure 11-21 for arsenic (PMio) measurements at NBIL include the
following:
Metals sampling at NBIL began in January 2005.
The maximum arsenic concentration was measured on July 12, 2009, although a
similar concentration was also measured in 2010.
The average concentrations exhibit little significant change over the course of
sampling. The average concentrations increased from 2005 to 2006, reached a
maximum for 2007 (0.86 ng/m3), and then returned to previous levels in 2008, after
which the average concentration has remained steady. Since 2008, the average
concentrations have ranged from 0.73 ng/m3 (2011) to 0.75 ng/m3 (2010).
Note that the minimum concentration for each year is greater than zero, indicating
that there were no non-detects of arsenic reported since the onset of metals sampling.
Observations from Figure 11-22 for benzene measurements at NBIL include the
following:
Although sampling for VOCs at NBIL began in 2003, sampling did not begin until
April, which does not yield enough samples for the statistical metrics to be calculated
for 2003, based on the criteria specified in Section 3.5.4. In addition, sampling for
VOCs was discontinued in October 2004 through the end of the year. Thus, Figure
11-22 begins with 2005.
The maximum benzene concentration was measured on January 9, 2011 and is the
only measurement greater than 4 |ig/m3 measured at NBIL.
The average (and median) concentration decreased significantly from 2005 to 2006,
and continued to decreased through 2007, then remained at the same level for 2008
and 2009. The average benzene concentration increased from 2009 to 2010. Even
with the maximum concentration measured in 2011, the average concentration
remained fairly static (and the 95th percentile actually decreased).
The minimum concentration for each year is greater than zero, indicating that there
were no non-detects of benzene reported for the years shown.
Observations from Figure 11-23 for 1,3-butadiene measurements at NBIL include the
following:
The maximum 1,3-butadiene concentration was measured on the same day as the
maximum benzene concentration, January 9, 2011 (2.68 |ig/m3). Only three
concentrations greater than 1 |ig/m3 have been measured at NBIL, two in 2011 and
one in 2010. All other measurements of 1,3-butadiene are less than 0.35 |ig/m3.
11-38
-------
The average concentration changed little through 2009, after which an increase is
shown.
Even with the relatively high concentrations measured in 2010 and 2011, the
95th percentile changed only slightly, indicating that the majority of the measurements
were still within the same range. For example, for 2011, only three measurements
were greater than the 95th percentile; this is also true for 2010.
For each year shown, the minimum and 5th percentile are zero, indicating the presence
of non-detects (at least 5 percent of the measurements). The number of non-detects
reported has fluctuated over the years of sampling, from as high as 43 percent (2005)
to as low as seven percent (2007).
Observations from Figure 11-24 for formaldehyde measurements at NBIL include the
following:
The maximum formaldehyde concentration was measured on January 5, 2006
(91.7 |ig/m3). However, the next five highest concentrations, ranging from 14.4 |ig/m3
to 53.5 |ig/m3, were all measured in 2010. The only other formaldehyde measurement
greater than 10 |ig/m3 was measured in 2011 (13.7 |ig/m3).
The maximum concentration measured in 2006 is 20 times higher than the next
highest concentration measured that year (4.46 |ig/m3). The magnitude of this outlier
explains why the average concentration for 2006 is greater than the 95th percentile.
The statistical metrics for 2010 are also affected by the higher concentrations;
however, concentrations measured this year are higher in general, as indicated by
seven-fold increase in the 95th percentile. Although difficult to discern in
Figure 11-24, the average concentration tripled from 2009 to 2010 and the median
increased by 50 percent. The concentrations measured in 2011 were less than those
measured in 2010, although still greater than most years.
Although difficult to discern in Figure 11-24, the minimum concentration for each
year is greater than zero, indicating that there were no non-detects of formaldehyde
reported for the years shown.
Observations from Figure 11-25 for hexavalent chromium measurements at NBIL include
the following:
Hexavalent chromium sampling at NBIL began in January 2005.
The maximum hexavalent chromium concentration was measured on July 5, 2007
(0.307 ng/m3). Only five additional measurements from NBIL are greater than
0.1 ng/m3, and range from 0.108 ng/m3 to 0.235 ng/m3. Four of the top six
concentrations were measured in 2006, with the fifth measured in 2005.
11-39
-------
Both the minimum concentration and 5th percentile for all years are zero, indicating
the presence of non-detects. For 2009, the median concentration is also zero,
indicating that at least 50 percent of the measurements are non-detects.
The average (and median) concentration of hexavalent chromium decreased
significantly between 2006 and 2009. The maximum, 95th percentile, median, and
average concentrations all exhibit an increase for 2010. For 2011, the range of
concentrations (based on the minimum and maximum concentrations as well as the
5th and 95th percentiles) is more similar to the statistical metrics for 2009, although
both the average and median concentrations are higher for 2011, most likely because
the number of non-detects is significantly lower (from 56 percent non-detects in 2009
down to 18 percent in 2011).
Observations from Figure 11-26 for lead (PMio) measurements at NBIL include the
following:
The maximum lead concentration was measured on July 5, 2007 (26.8 ng/m3), which
is the same day the maximum hexavalent chromium concentration was measured. The
only other concentration greater than 20 ng/m3 was measured in October 2011.
The average concentrations exhibit a decreasing trend from 2008 through 2010, but
increased in 2011 back to 2008 levels.
The average and median concentrations differ by nearly 1 ng/m3 for each year.
The minimum concentration for each year is greater than zero, indicating that there
were no non-detects of lead reported since the onset of metals sampling.
Observations from Figure 11-27 for manganese (PMio) measurements at NBIL include
the following:
The maximum manganese concentration was measured on August 26, 2005
(54.6 ng/m3). Concentrations in the 40-45 ng/m3 range have been measured in 2005,
2008, and 2010.
The average concentration decreased significantly from 2005 to 2006. Note that the
average concentration for 2005 is greater than or similar to the 95th percentiles for
some of the years that follow. After 2005, changes in the averages are statistically
insignificant.
Nearly all of the statistical metrics are at a minimum for 2009.
The minimum concentration for each year is greater than zero, indicating that there
were no non-detects of manganese reported since the onset of metals sampling.
11-40
-------
Observations from Figure 11-28 for acetaldehyde measurements at SPIL include the
following:
Although carbonyl compound sampling at SPIL began in 2005, sampling did not
begin in earnest until March, which does not yield enough samples for the statistical
metrics to be calculated for 2005, based on the criteria specified in Section 3.5.4.
Thus, Figure 11-28 begins with 2006.
The maximum acetaldehyde concentration was measured on January 9, 2011. The
four highest concentrations of acetaldehyde were measured in 2011 and of the 10
acetaldehyde concentrations greater than 5.0 |ig/m3 measured at SPIL, eight measured
in 2011.
The average concentration decreased from 2006 to 2007, then held steady through
2009. The average concentration increased slightly in 2010 then increased
significantly in 2011. All of the statistical metrics increased for 2011, including the
95th percentile, indicating that the increases shown are not attributable to a handful of
outliers.
Note that the minimum concentration for each year is greater than zero, indicating
that there were no non-detects of acetaldehyde reported for SPIL over the period
shown.
Observations from Figure 11-29 for benzene measurements at SPIL include the
following:
Although sampling for VOCs at SPIL began in 2003, sampling did not begin in until
April 2003, which does not yield enough samples for the statistical metrics to be
calculated for 2003, based on the criteria specified in Section 3.5.4. Thus,
Figure 11-29 begins with 2004.
The maximum benzene concentration was measured on October 13, 2005, although a
similar concentration was also measured in February 2005.
The average benzene concentration has decreased over the years, reaching a
minimum of 0.68 |ig/m3 for 2009. The average concentration then increased for 2010,
with a slight decrease for 2011.
The minimum concentration for each year is greater than zero, indicating that no non-
detects of benzene have been reported for SPIL over the period shown.
11-41
-------
Observations from Figure 11-30 for 1,3-butadiene measurements at SPIL include the
following:
The maximum concentration of 1,3-butadiene was measured on February 3, 2005
(1.29 |ig/m3) and is the only measurement greater than 1 |ig/m3. Only five
concentrations greater than 0.5 |ig/m3 have been measured at SPIL, one in 2004, two
in 2005, and two in 2011.
The average concentration of 1,3-butadiene began to decrease in 2007 and reached a
minimum in 2009 (0.085 |ig/m3). The increase from 2009 to 2010 is significant, with
a 40 percent increase from 2009 levels. The median concentrations follow a similar
pattern.
The range of concentrations measured, as indicated by both the minimum and
maximum concentrations and the 5th and 95th percentiles, has been decreasing over
the years, but increased significantly for 2010, which continued into 2011.
The detection rate for 1,3-butadiene has increased over time, ranging from
approximately 45 percent non-detects in 2004 down to zero in 2008 and 2009 and one
non-detect each for 2010 and 2011.
Observations from Figure 11-31 for formaldehyde measurements at SPIL include the
following:
The maximum formaldehyde concentration was measured on May 29, 2006 and is
more than 10 times the maximum concentrations for any of the other years shown in
Figure 11-31. Of the 26 formaldehyde concentrations greater than 10 |ig/m3, all but
two were measured in 2006.
The average concentration for 2006 is 13.76 |ig/m3. After 2006, the average
concentration decreased each year, reaching a minimum of 1.85 |ig/m3 for 2009.
Although difficult to discern in Figure 11-31, the average concentration has increased
each year since 2009.
11-42
-------
11.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each Illinois monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
11.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Illinois monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
11.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Illinois sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 11-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
11-43
-------
Table 11-6. Risk Approximations for the Illinois Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Northbrook, Illinois - NBIL
Acenaphthene a
Acetaldehyde
Acrylonitrile
Arsenic (PM10)a
Benzene
Benzo(a)pyrene a
Bery Ilium (PM10)a
1,3 -Butadiene
Cadmium (PM10)a
Carbon Tetrachloride
Chloroform
1,2-Dichloroethane
Ethylbenzene
Fluoranthene a
Fluorene a
Formaldehyde
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.000088
0.0000022
0.000068
0.0043
0.0000078
0.00176
0.0024
0.00003
0.0018
0.000006
_
0.000026
0.0000025
0.000088
0.000088
0.000013
0.012
..
__
0.000034
0.00048
0.00000026
0.0000048
0.0000088
_
0.009
0.002
0.000015
0.03
_
0.00002
0.002
0.00001
0.1
0.098
2.4
1
_
_
0.0098
0.0001
0.00015
0.00005
0.003
0.00009
0.04
0.002
0.1
61/61
62/62
35/55
53/53
55/55
59/61
51/53
41/55
53/53
55/55
55/55
18/55
55/55
61/61
61/61
62/62
50/61
53/53
53/53
61/61
53/53
53/55
24/55
8/55
0.01
ฑ<0.01
1.41
ฑ0.20
0.13
ฑ0.03
<0.01
ฑ<0.01
0.71
ฑ0.16
<0.01
ฑ<0.01
<0.01
ฑ<0.01
0.12
ฑ0.10
<0.01
ฑ<0.01
0.64
ฑ0.03
6.06
ฑ2.17
0.03
ฑ0.01
0.32
ฑ0.12
0.01
ฑ<0.01
0.01
ฑ<0.01
2.53
ฑ0.57
<0.01
ฑ<0.01
<0.01
ฑ<0.01
0.01
ฑ<0.01
0.10
ฑ0.03
<0.01
ฑ<0.01
0.35
ฑ0.13
0.04
ฑ0.02
<0.01
ฑ<0.01
1.16
3.11
9.07
3.15
5.53
0.26
0.02
3.45
0.26
3.84
_
0.67
0.80
0.67
1.18
32.89
0.20
_
3.38
0.61
0.09
0.21
0.03
_
0.16
0.07
0.05
0.02
..
0.01
0.06
0.01
0.01
0.06
0.01
0.01
_
_
0.26
0.01
0.03
0.17
0.03
0.01
0.01
0.02
O.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 11-5.
11-44
-------
Table 11-6. Risk Approximations for the Illinois Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Schiller Park, Illinois - SPIL
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0000078
0.00003
0.000006
_
0.000011
0.000026
0.000013
0.00000026
0.0000048
0.0000088
0.009
0.002
0.03
0.002
0.1
0.098
0.8
2.4
0.0098
0.04
0.002
0.1
62/62
47/56
56/56
55/56
56/56
38/56
33/56
15/56
62/62
53/56
42/56
6/56
2.94
ฑ0.61
0.77
ฑ0.11
0.85
ฑ0.12
0.16
ฑ0.03
0.58
ฑ0.02
0.09
ฑ0.02
0.07
ฑ0.03
0.02
ฑ0.01
3.29
ฑ0.46
0.31
ฑ0.08
0.64
ฑ0.41
<0.01
ฑ<0.01
6.48
52.22
6.64
4.69
3.50
_
0.80
0.59
42.81
0.08
3.05
0.03
0.33
0.38
0.03
0.08
0.01
0.01
0.01
0.01
0.34
0.01
0.32
0.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 11-5.
Observations for NBIL from Table 11-6 include the following:
Chloroform, formaldehyde, and acetaldehyde are the pollutants with the highest
annual average concentrations for NBIL.
Formaldehyde, acrylonitrile, and benzene have the highest cancer risk
approximations.
None of NBIL's pollutants of interest have noncancer hazard approximations greater
than 1.0, indicating that no adverse health effects are expected from these individual
pollutants. The pollutant with the highest noncancer hazard approximation is
formaldehyde (0.26).
Note that chloroform, which has the highest annual average for NBIL, has no cancer
URE. The noncancer hazard approximation for this pollutant is low (0.06).
11-45
-------
Observations for SPIL from Table 11-6 include the following:
Formaldehyde, acetaldehyde, and benzene are the pollutants with the highest annual
average concentrations for SPIL.
Acrylonitrile has the highest cancer risk approximation for SPIL (52.22 in-a-million),
followed by formaldehyde (42.81 in-a-million). The cancer risk approximation for
acrylonitrile is the fifth highest cancer risk approximation among all site-specific
pollutants of interest and the only pollutant besides formaldehyde program-wide with
a cancer risk approximation greater than 30 in-a-million.
None of SPIL's pollutants of interest have noncancer hazard approximations greater
than 1.0, indicating that no adverse health effects are expected from these individual
pollutants. The pollutants with the highest noncancer hazard approximations are
acrylonitrile and formaldehyde (0.38 and 0.34, respectively) although acetaldehyde
and trichloroethylene have noncancer hazard approximations of similar magnitudes.
In most cases, the risk approximations for SPIL are greater than the risk
approximations for NBIL. This is most apparent for acrylonitrile, formaldehyde, and
trichloroethylene, with chloroform being the exception.
11.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 11-7 and 11-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 11-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from annual averages provided in
Table 11-6. Table 11-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 11-6.
11-46
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Table 11-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Illinois Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Northbrook, Illinois (Cook County) - NBIL
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Tetrachloroethylene
Trichloroethylene
Naphthalene
Dichloromethane
POM, Group 2b
1,445.06
1,055.89
791.28
689.38
209.30
190.73
134.75
126.41
93.18
20.55
Formaldehyde
Benzene
Hexavalent Chromium, PM
1,3 -Butadiene
Naphthalene
Cadmium, PM
Nickel, PM
Arsenic, PM
Ethylbenzene
POM, Group 2b
1.37E-02
1.13E-02
6.92E-03
6.28E-03
4.30E-03
2.67E-03
2.44E-03
2.17E-03
1.98E-03
1.81E-03
Formaldehyde
Acrylonitrile
Benzene
Carbon Tetrachloride
1,3 -Butadiene
Naphthalene
Arsenic
Acetaldehyde
Fluorene
Acenaphthene
32.89
9.07
5.53
3.84
3.45
3.38
3.15
3.11
1.18
1.16
Schiller Park, Illinois (Cook County) - SPIL
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Tetrachloroethylene
Trichloroethylene
Naphthalene
Dichloromethane
POM, Group 2b
1,445.06
1,055.89
791.28
689.38
209.30
190.73
134.75
126.41
93.18
20.55
Formaldehyde
Benzene
Hexavalent Chromium, PM
1,3 -Butadiene
Naphthalene
Cadmium, PM
Nickel, PM
Arsenic, PM
Ethylbenzene
POM, Group 2b
1.37E-02
1.13E-02
6.92E-03
6.28E-03
4.30E-03
2.67E-03
2.44E-03
2.17E-03
1.98E-03
1.81E-03
Acrylonitrile
Formaldehyde
Benzene
Acetaldehyde
1,3 -Butadiene
Carbon Tetrachloride
Trichloroethylene
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Tetrachloroethylene
52.22
42.81
6.64
6.48
4.69
3.50
3.05
0.80
0.59
0.08
-------
Table 11-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Illinois Monitoring Sites
oo
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Northbrook, Illinois (Cook County) - NBIL
Toluene
Xylenes
Methanol
1,1,1 -Trichloroethane
Methyl isobutyl ketone
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
5,432.03
3,804.27
3,800.86
3,014.08
2,290.29
1,445.06
1,055.89
1,006.50
791.28
689.38
Acrolein
Manganese, PM
Cadmium, PM
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Trichloroethylene
Nickel, PM
Benzene
Naphthalene
3,705,826.42
161,905.82
148,156.47
107,743.48
104,651.38
76,598.28
67,372.78
56,590.58
48,168.61
42,137.52
Formaldehyde
Manganese
Acetaldehyde
Acrylonitrile
Chloroform
1,3 -Butadiene
Arsenic
Naphthalene
Lead
Benzene
0.26
0.17
0.16
0.07
0.06
0.06
0.05
0.03
0.03
0.02
Schiller Park, Illinois (Cook County) - SPIL
Toluene
Xylenes
Methanol
1,1,1 -Trichloroethane
Methyl isobutyl ketone
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
5,432.03
3,804.27
3,800.86
3,014.08
2,290.29
1,445.06
1,055.89
1,006.50
791.28
689.38
Acrolein
Manganese, PM
Cadmium, PM
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Trichloroethylene
Nickel, PM
Benzene
Naphthalene
3,705,826.42
161,905.82
148,156.47
107,743.48
104,651.38
76,598.28
67,372.78
56,590.58
48,168.61
42,137.52
Acrylonitrile
Formaldehyde
Acetaldehyde
Trichloroethylene
1,3 -Butadiene
Benzene
Tetrachloroethylene
Carbon Tetrachloride
Chloroform
/>-Dichlorobenzene
0.38
0.34
0.33
0.32
0.08
0.03
0.01
0.01
<0.01
<0.01
-------
The pollutants listed in Tables 11-7 and 11-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 11.3, SPIL sampled for VOCs and carbonyl compounds. NBIL sampled for these
pollutants as well, but also sampled for SNMOCs, PMi0 metals, PAHs, and hexavalent
chromium. In addition, the cancer risk and noncancer hazard approximations are limited to those
pollutants with enough data to meet the criteria for annual averages to be calculated. A more in-
depth discussion of this analysis is provided in Section 3.5.5.3. Similar to the cancer risk and
noncancer hazard approximations, this analysis may help policy-makers prioritize their air
monitoring activities.
Observations from Table 11-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Cook County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
cancer UREs) for Cook County are formaldehyde, benzene, and hexavalent
chromium.
Six of the highest emitted pollutants in Cook County also have the highest toxicity -
weighted emissions.
For both monitoring sites, formaldehyde, acrylonitrile, and benzene have the highest
cancer risk approximations, although not necessarily in that order. Formaldehyde and
benzene are the top two pollutants on both emissions-based lists, while acrylonitrile
appears on neither emissions-based list.
Carbon tetrachloride, which also appears among the pollutants with the highest cancer
risk approximations for both sites, does not appear on either emissions-based list.
Several metals appear among the pollutants with the highest toxicity-weighted
emissions, including arsenic, which has the seventh highest cancer risk approximation
for NBIL. SPIL did not sample metals. None of these metals appear among the
highest emitted pollutants.
NBIL is one of two NMP sites that sampled pollutants from all six methods. At least
one pollutant from each of the six methods appears among the pollutants with the
highest toxicity-weighted emissions.
11-49
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POM, Group 2b ranks tenth for both the quantity emitted and the toxicity-weighted
emissions in Cook County. POM, Group 2b includes acenaphthene, fluorene, and
fluoranthene, all three of which are pollutants of interest for NBIL.
Observations from Table 11-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in Cook County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) for Cook County are acrolein, manganese, and cadmium. Although
acrolein was sampled for at both NBIL and SPIL, this pollutant was excluded from
the pollutants of interest designation, and thus subsequent risk-based screening
evaluations, due to questions about the consistency and reliability of the
measurements, as discussed in Section 3.2.
Three of the highest emitted pollutants also have the highest toxicity-weighted
emissions (benzene, formaldehyde, and acetaldehyde).
Formaldehyde, manganese, and acetaldehyde have the highest noncancer hazard
approximations for NBIL (albeit less than an HQ of 1.0). Formaldehyde and
acetaldehyde appear on both emissions-based lists while manganese has the second
highest toxicity-weighted emissions, but is not among the highest emitted pollutants
in Cook County.
Acrylonitrile has the highest noncancer hazard approximation for SPIL (albeit less
than an HQ of 1.0). This pollutant appears on neither emissions-based list.
11.6 Summary of the 2011 Monitoring Data for NBIL and SPIL
Results from several of the data treatments described in this section include the
following:
ปซป Twenty-four pollutants, including 13 NA TTS MQO Core Analytes, failed screens for
NBIL. Sixteen pollutants, including six NATTS MQO Core Analytes, failed screens for
SPIL.
ปซป The pollutant with the highest annual average concentration among the pollutants of
interest for NBIL was chloroform. NBIL's annual average concentration of
chloroform was the highest annual average among allNMP sites sampling this
pollutant.
ปซป The pollutant with the highest annual average concentration among the pollutants of
interest for SPIL was formaldehyde.SPIL has the highest annual average
concentration of acrylonitrile and trichloroethylene among NMP sites sampling these
pollutants.
11-50
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Concentrations of acetaldehyde and 1,5'-butadiene have been increasing in recent
years at NBIL and SPIL.
11-51
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12.0 Sites in Indiana
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the UATMP sites in Indiana, and integrates these concentrations with
emissions, meteorological, and risk information. Data generated by sources other than ERG are
not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
12.1 Site Characterization
This section characterizes the Indiana monitoring sites by providing geographical and
physical information about the location of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
One Indiana site (INDEM) is located in the Chicago-Naperville-Joliet, IL-IN-WI MSA,
while a second site (WPIN) is located in the Indianapolis-Carmel, IN MSA. Figures 12-1 and
12-3 are composite satellite images retrieved from ArcGIS Explorer showing the monitoring
sites in their urban locations. Figures 12-2 and 12-4 identify nearby point source emissions
locations by source category near INDEM and WPIN, respectively, as reported in the 2008 NEI
for point sources. Note that only sources within 10 miles of the sites are included in the facility
counts provided in Figures 12-2 and 12-4. A 10-mile boundary was chosen to give the reader an
indication of which emissions sources and emissions source categories could potentially have a
direct effect on the air quality at the monitoring sites. Further, this boundary provides both the
proximity of emissions sources to the monitoring sites as well as the quantity of such sources
within a given distance of the sites. Sources outside the 10-mile radius are still visible on each
map, but have been grayed out in order to show emissions sources just outside the boundary.
Table 12-1 provides supplemental geographical information such as land use, location setting,
and locational coordinates.
12-1
-------
Figure 12-1. Gary, Indiana (INDEM) Monitoring Site
to
to
-------
Figure 12-2. NEI Point Sources Located Within 10 Miles of INDEM
87 20'CTW 87'15'CrW STIWW
Note: Due to facility density and collocation, the total facilities
displayed may not represent alt facilities within the area of interest.
INDEM UATMP site 10 mile radius | | County boundary
x Mine/Quarry (3)
V Mineral Products (7)
? Miscellaneous Commeraal/lndustrial (24)
M Miscellaneous Manufacturing (1)
Oil and/or Gas Production (3)
^ Petroleum Refinery (1)
1 Primary Metal Production (1)
B Pulp and Paper Plant/Wood Products (1)
R Rubber and Miscellaneous Plastics Products (1)
> Solid Waste Disposal - Commercial/Institutional (1)
V Steel Mill (14)
S Surface Coating (1)
* Transportation and Marketing of Petroleum Products (6)
Source Category Group (No. of Facilities)
-t1 Aircraft Operations (14)
i Asphalt Processing/Roofing Manufacturing (1)
B Bulk Terminals/Bulk Plants (7)
c Chemical Manufacturing (5)
S Coke Battery (1)
* Electricity Generation via Combustion (6)
ฉ Fabricated Metal Products (3)
F Food Processing/Agriculture (1)
+ Gypsum Manufacturing (1)
'i Hot Mix Asphalt Plant (1)
Landfill (1)
> Lime Manufacturing (1)
12-3
-------
Figure 12-3. Indianapolis, Indiana (WPIN) Monitoring Site
to
-------
Figure 12-4. NEI Point Sources Located Within 10 Miles of WPIN
Legend
86'10'D-W aa'S'O'W 88'ffO'W 85"55"OTV
Note: Due to facility density and collocation, the total facilities
displayed may nol represent all facilities within the area of interest.
WPIN UATMP site
10 mile radius
County boundary
41
B
c
Source Category Group (No. of Facilities)
Flexible Polyurethane Foam Production (2)
A Grain Handling (2)
^ Institutional -school (1)
Iron and Steel Foundry (1)
Landfill (1)
Miscellaneous Commercial/Industrial (1)
Municipal Waste Combustor (1)
Oil and/or Gas Production (1)
Pharmaceutical Manufacturing (2)
Steel Mill(1)
Surface Coating (4}
Transportation Equipment (1)
Wastewater Treatment (1)
12-5
-------
Table 12-1. Geographical Information for the Indiana Monitoring Sites
Site
Code
INDEM
WPIN
AQS Code
18-089-0022
18-097-0078
Location
Gary
Indianapolis
County
Lake
Marion
Micro- or
Metropolitan
Statistical Area
Chicago-Joliet-
Naperville, IL-IN-
WIMSA
(Gary Div)
Indianapolis-
Carmel, IN MSA
Latitude
and
Longitude
41.606667,
-87.304722
39.811097,
-86.114469
Land Use
Industrial
Residential
Location
Setting
Urban/City
Center
Suburban
Additional Ambient Monitoring Information1
VOCs, SO2, NO, NO2, NOX, PAMS, O3,
Meteorological parameters, PM10, Black carbon,
UV Carbon, PM2 5, and PM2 5 Speciation,
Tetrahydrofuran, 1,4-Dioxane.
TSP Metals, CO, VOCs, SNMOCs, SO2, NOy, NO,
O3, Meteorological parameters, PM10, Black carbon,
UV Carbon, PM2 5, and PM2 5 Speciation,
Tetrahydrofuran, 1,4-Dioxane, PM Coarse.
Data for additional pollutants are reported to AQS for these sites (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this report
to
-------
INDEM is located in Gary, Indiana, a few miles east of the Indiana-Illinois border and
southeast of Chicago. Gary is located on the southernmost bank of Lake Michigan. The site is
located just north of 1-90, the edge of which can be seen in the bottom left portion of
Figure 12-1, and 1-65. Although INDEM resides on the Indiana Dunes National Lakeshore, the
surrounding area is highly industrialized, as shown in Figure 12-1, and several railroads
transverse the area. Figure 12-2 shows that the majority of point sources within 10 miles of
INDEM are located to the west of the site. The sources closest to INDEM are a mine/quarry, a
steel mill, and a facility that falls into the miscellaneous commercial/industrial category. The
emissions source categories with the highest number of sources within 10 miles of INDEM
include steel mills; aircraft operations; mineral products; and bulk terminals and plants.
WPIN is located in the parking lot of George Washington Park, near East 30th Street in
northeast Indianapolis. Figure 12-3 shows that the area surrounding WPIN is suburban and
residential, with little industry in close proximity. A church and a charitable organization are
located across the street from Washington Park, as is Oscar Charleston Park. Figure 12-4 shows
that the majority of point sources are located to the south and southwest of WPIN, towards the
center of Marion County. The source category with the highest number of sources near WPIN is
the aircraft operations source category, which include airports as well as small runways,
heliports, or landing pads. The sources closest to WPIN are an aircraft operations facility and a
fabricated metal products facility.
Table 12-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Indiana monitoring sites. Table 12-2 includes county-level
population and vehicle registration information. Table 12-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 12-2 also
contains traffic volume information for each site. Finally, Table 12-2 presents the county-level
daily VMT for Marion and Lake Counties.
12-7
-------
Table 12-2. Population, Motor Vehicle, and Traffic Information for the Indiana Monitoring
Sites
Site
INDEM
WPIN
Estimated
County
Population1
495,558
911,296
County-level
Vehicle
Registration2
419,431
820,767
Vehicles per
Person
(Registration:
Population)
0.85
0.90
Population
within 10
miles3
411,932
797,291
Estimated
10-mile
Vehicle
Ownership
348,652
718,087
Annual
Average
Daily
Traffic4
34,240
143,970
County-
level Daily
VMT5
16,226,000
32,005,000
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Indiana Bureau of Motor Vehicles (IN BMV, 2012)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4 AADT reflects 2010 data from the Indiana DOT (IN DOT, 2010)
5County-level VMT reflects 2011 data from the Indiana DOT (IN DOT, 2012)
Observations from Table 12-2 include the following:
Marion County has almost twice the county-level population and vehicle registration
as Lake County. The 10-mile population and estimated vehicle registration follow a
similar pattern as the county-level values.
The county-level and 10-mile populations are in the middle third of populations
among NMP sites as are the county-level and 10-mile vehicle registrations.
The vehicle-per-person ratios for both Indiana sites are in the middle of the range
among the ratios for NMP sites.
WPIN experiences a significantly higher traffic volume than INDEM. The traffic
estimate for WPIN is based on data from 1-70 between exits 85 and 87 while the
traffic volume for INDEM is based on data from 1-90 at 12/20. The traffic volume
near WPIN is the seventh highest among NMP sites.
The VMT for Marion County is almost twice the VMT for Lake County. The Marion
County VMT ranked tenth among counties with NMP sites, while the VMT for Lake
County is in the middle of the range (19th).
12.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Indiana on sample days, as well as over the course of the year.
12.2.1 Climate Summary
The city of Gary is located to the southeast of Chicago, and at the southern-most tip of
Lake Michigan. Gary's proximity to Lake Michigan is an important factor controlling the
weather of the area. In the summer, warm temperatures can be suppressed, while cold winter
temperatures are often moderated. Winds that blow across Lake Michigan and over Gary in the
12-8
-------
winter can provide abundant amounts of lake-effect snow while lake breezes can bring relief
from summer heat (Bair, 1992; Gary, 2013; and ISCO, 2002).
The city of Indianapolis is located in the center of Indiana, and experiences a temperate
continental climate and frequently changing weather patterns. Summers are warm and often
humid, as moist air flows northward out of the Gulf of Mexico. Winters are chilly with
occasional Arctic outbreaks. Precipitation is spread rather evenly throughout the year, with much
of the spring and summer precipitation resulting from showers and thunderstorms. The
prevailing wind direction is southwesterly (Bair, 1992 and ISCO, 2002).
12.2.2 Meteorological Conditions in 2011
Hourly meteorological data from NWS weather stations nearest these sites were retrieved
for 2011 (NCDC, 2011). The two closest weather stations are located at Lansing Municipal
Airport (near INDEM) and Eagle Creek Airpark (near WPIN), WBAN 04879 and 53842,
respectively. Additional information about these weather stations, such as the distance between
the sites and the weather stations, is provided in Table 12-3. These data were used to determine
how meteorological conditions on sample days vary from conditions experienced throughout the
year.
Table 12-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 12-3 is the
95 percent confidence interval for each parameter. As shown in Table 12-3, average
meteorological conditions on sample days were representative of average weather conditions
throughout the year for WPIN. For INDEM, sample days appear slightly cooler and less moist
than all days throughout 2011, although the difference is not statistically significant.
12-9
-------
Table 12-3. Average Meteorological Conditions near the Indiana Monitoring Sites
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Gary, Indiana - INDEM |
Lansing Municipal
Airport
04879
(41.54, -87.52)
11.36
miles
241ฐ
(WSW)
Sample
Day
2011
58.0
ฑ5.8
59.3
ฑ2.2
49.6
ฑ5.2
51.1
ฑ2.0
40.3
ฑ4.8
42.2
ฑ1.9
45.0
ฑ4.7
46.6
ฑ 1.8
72.9
ฑ2.7
74.1
ฑ1.2
NA
NA
7.2
ฑ0.9
7.0
ฑ0.4
Indianapolis, Indiana - WPIN
Eagle Creek
Airpark
53842
(39.83, -86.30)
9.13
miles
270ฐ
(W)
Sample
Day
2011
61.3
ฑ5.2
62.3
ฑ2.1
53.1
ฑ5.0
54.1
ฑ1.9
42.9
ฑ4.7
43.6
ฑ1.8
47.9
ฑ4.5
48.7
ฑ1.7
71.1
ฑ3.1
70.3
ฑ1.2
1016.3
ฑ1.7
1015.6
ฑ0.7
5.6
ฑ0.7
5.7
ฑ0.3
to
o
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
NA= Sea level pressure was not recorded at the Lansing Municipal Airport
-------
12.2.3 Back Trajectory Analysis
Figure 12-5 is the composite back trajectory map for days on which samples were
collected at the INDEM monitoring site in 2011. Included in Figure 12-5 are four back
trajectories per sample day. Figure 12-6 is the corresponding cluster analysis. Similarly,
Figure 12-7 is the composite back trajectory map for days on which samples were collected at
WPIN and Figure 12-8 is the corresponding cluster analysis. An in-depth description of these
maps and how they were generated is presented in Section 3.5.2.1. For the composite maps, each
line represents the 24-hour trajectory along which a parcel of air traveled toward the monitoring
site on a given sample day and time, based on an initial height of 50 meters AGL. For the cluster
analyses, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the sites in Figures 12-5 through 12-8 represents
100 miles.
Observations from Figures 12-5 and 12-6 for INDEM include the following:
Back trajectories originated from a variety of directions at INDEM.
The 24-hour air shed domain for INDEM was among the larger in size compared to
other NMP sites, with an average trajectory length of 263 miles. The farthest away a
back trajectory originated was over northwest North Dakota, or nearly 875 miles
away. However, most trajectories (approximately 90 percent) originated within 450
miles of INDEM, with the longest trajectories originating from the west, northwest,
and north.
The short cluster trajectory originating over Lake Michigan represents nearly one-
third of back trajectories and includes trajectories originating from a direction with a
northerly component and within 200 miles of the sites. Twenty-two percent of
trajectories originated from the southwest of INDEM over Illinois and Missouri.
Another 21 percent of back trajectories originated from the west to northwest to north
of the site. Fifteen percent of trajectories originated from the southeast quadrant while
11 percent originated from the northeast quadrant.
12-11
-------
Figure 12-5. 2011 Composite Back Trajectory Map for INDEM
Figure 12-6. Back Trajectory Cluster Map for INDEM
12-12
-------
Figure 12-7. 2011 Composite Back Trajectory Map for WPIN
Figure 12-8. Back Trajectory Cluster Map for WPIN
12-13
-------
Observations from Figures 12-7 and 12-8 for WPIN include the following:
The composite back trajectory map for WPIN shows that back trajectories originated
from a variety of directions, similar to INDEM.
The 24-hour air shed domain for WPIN is similar in size to many other NMP
monitoring sites, with an average trajectory length of 225 miles. The farthest away a
back trajectory originated was over eastern North Dakota, or greater than 750 miles
away, although most trajectories (90 percent) originated within 400 miles of WPIN.
Back trajectories originating to the northwest and north tended to be the longest.
The cluster analysis for WPIN shows that back trajectories originating from the
northwest account for nearly one-third of back trajectories but are split into two
cluster trajectories to account for varying lengths of trajectories. The shorter cluster
trajectory originating over Illinois (21 percent) represents back trajectories originating
from the west, northwest, and north and generally less than 250 miles in length. The
short cluster trajectory originating over northern Kentucky represents back
trajectories originating from the east, southeast, and south but of varying distances.
Back trajectories also originated southwestward over Illinois and Kentucky; over
Ohio, Michigan, and the eastern Great Lakes; and northward over Michigan and
Lakes Michigan, Superior, and Huron, and parts of Ontario, Canada.
12.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations near the Indiana sites, as
presented in Section 12.2.2, were uploaded into a wind rose software program to produce
customized wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind
directions using "petals" positioned around a 16-point compass, and uses different colors to
represent wind speeds.
Figure 12-9 presents a map showing the distance between the NWS station and INDEM,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 12-9 also presents three different wind roses for the
INDEM monitoring site. First, a historical wind rose representing 2003 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figure 12-10 presents the distance map and three wind roses
for WPIN.
12-14
-------
Figure 12-9. Wind Roses for the Lansing Municipal Airport Weather Station near INDEM
Distance between INDEM and NWS Station
2003-2010 Historical Wind Rose
:
lTt.im.lI _
uปn inn-Minim ;
,H if.rtปi i
'
;,,'
2011 Wind Rose
Sample Day Wind Rose
12-15
-------
Figure 12-10. Wind Roses for the Indianapolis International Airport Weather Station near
WPIN
Distance between WPIN and NWS Station
2001-2010 Historical Wind Rose
\ GRAHDUIEW
= W MUSIC B
._/ . ', rซK,,,0r O
V, \ ! *- >,; ;
2011 Wind Rose
Sample Day Wind Rose
12-16
-------
Observations from Figure 12-9 for INDEM include the following:
The NWS weather station at Lancing Municipal Airport is the closest weather station
to INDEM, although it is located approximately 11.4 miles west-southwest of
INDEM. The location of the weather station is just east of the Illinois-Indiana state
line and farther inland than INDEM and thus, farther away from the influences of
Lake Michigan than INDEM.
The historical wind rose for INDEM shows that winds from the south to south-
southwest and west are the predominant wind directions over the 2003-2010 time
frame. Northerly to northeasterly winds off Lake Michigan accounted for just less
than 20 percent of the wind measurements, as did calm winds. The strongest winds
blew from the south to southwest to west of INDEM.
The wind patterns shown on the 2011 wind rose resemble the wind patterns shown on
the historical wind rose, although there are slightly fewer calm winds.
The sample day wind rose exhibits similarities with the historical and full-year wind
roses, but differences are also evident. The calm rate is lower and there is a higher
percentage of winds from the southeast quadrant. Winds from the east-southeast to
south-southeast account for approximately three times as many wind observations on
sample days as they did throughout the year.
Observations from Figure 12-10 for WPIN include the following:
The NWS weather station at Eagle Creek Airpark is the closest weather station to
WPIN and is located approximately 9.1 miles west of WPIN. Eagle Creek Airpark is
located on the southeast edge of the Eagle Creek Reservoir.
Winds from the south, from the western quadrants, and from the north account for the
majority (nearly 60 percent) of wind observations from 2001-2010, while winds from
the eastern quadrants were observed less than one-quarter of the time. Calm winds
(< 2 knots) were observed for nearly 18 percent of observations. The strongest winds
tended to flow from the northwest.
The wind patterns on the 2011 wind rose resemble the historical wind patterns,
although there were fewer northwesterly winds and more northerly winds.
The sample day wind rose has a significantly higher number of winds from the east to
south-southeast than the full-year wind rose. A similar observation is noted for the
INDEM sample day wind rose. There were also fewer northerly and westerly wind
observations on sample days.
12-17
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12.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Indiana monitoring sites in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
For each site, each pollutant's preprocessed daily measurement was compared to its associated
risk screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by each monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 12-4 presents the results of the preliminary risk-based screening process for the
Indiana monitoring sites. The pollutants that failed at least one screen and contributed to 95
percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. INDEM and WPIN
sampled for carbonyl compounds only.
Table 12-4. Risk-Based Screening Results for the Indiana Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Gary, Indiana - INDEM
Acetaldehyde
Formaldehyde
Propionaldehyde
0.45
0.077
0.8
Total
57
57
1
115
57
57
57
171
100.00
100.00
1.75
67.25
49.57
49.57
0.87
49.57
99.13
100.00
Indianapolis, Indiana - WPIN
Acetaldehyde
Formaldehyde
0.45
0.077
Total
51
51
102
51
51
102
100.00
100.00
100.00
50.00
50.00
50.00
100.00
Observations from Table 12-4 include the following:
Formaldehyde, acetaldehyde, and propionaldehyde are the only carbonyl compounds
with risk screening values.
12-18
-------
All three carbonyl compounds with risk screening values failed screens for INDEM.
Acetaldehyde and formaldehyde failed 100 percent of screens while propionaldehyde
failed only one screen.
Acetaldehyde and formaldehyde failed screens for WPIN. They contributed equally
to the total number of failed screens. Both pollutants failed 100 percent of total failed
screens.
12.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Indiana monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Indiana monitoring sites, where the data meet the applicable
criteria. Concentration averages for select pollutants are also presented graphically for the sites to
illustrate how the sites' concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the sites. Additional site-
specific statistical summaries for INDEM and WPIN are provided in Appendix L.
12.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Indiana site, as described in Section 3.1. The quarterly average of a particular pollutant
is simply the average concentration of the preprocessed daily measurements over a given
calendar quarter. Quarterly average concentrations include the substitution of zeros for all non-
detects. A site must have a minimum of 75 percent valid samples of the total number of samples
possible within a given quarter for a quarterly average to be calculated. An annual average
includes all measured detections and substituted zeros for non-detects for the entire year of
sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Indiana monitoring
sites are presented in Table 12-5, where applicable. Note that if a pollutant was not detected in a
given calendar quarter, the quarterly average simply reflects "0" because only zeros substituted
for non-detects were factored into the quarterly average concentration.
12-19
-------
Table 12-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest
for the Indiana Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Gary, Indiana - INDEM
Acetaldehyde
Formaldehyde
57/57
57/57
1.11
ฑ0.15
2.02
ฑ0.19
NA
NA
1.43
ฑ0.24
3.03
ฑ0.69
1.43
ฑ0.35
1.86
ฑ0.48
1.27
ฑ0.13
2.30
ฑ0.27
Indianapolis, Indiana - WPIN
Acetaldehyde
Formaldehyde
51/51
51/51
NA
NA
3.11
ฑ0.49
6.24
ฑ1.32
2.51
ฑ0.46
4.69
ฑ0.86
1.74
ฑ0.37
2.50
ฑ0.46
NA
NA
Observations for the Indiana sites from Table 12-5 include the following:
The annual average concentration of formaldehyde is greater than the annual average
concentration of acetaldehyde for INDEM.
Second quarter average concentrations could not be calculated for INDEM due to too
many invalidated samples within that quarter.
Intermittent sampler issues resulted in a lack of first quarter and annual averages for
WPIN. However, Appendix L provides the pollutant-specific average concentrations
for all valid samples collected over the entire sample period for each site.
The second quarter averages of acetaldehyde and formaldehyde are higher than the
other quarterly averages for WPIN. The confidence interval for the second quarter
formaldehyde average is rather large, indicating the potential influence of outliers. A
review of the data shows that the highest formaldehyde concentration for WPIN was
measured on June 8, 2011 (11.1 |ig/m3). Four of the six highest concentrations of
formaldehyde (those greater than 6 |ig/m3) were measured at WPIN during the second
quarter. Concentrations of formaldehyde ranged from 1.41 |ig/m3to 11.1 |ig/m3 with a
median concentration of 4.22 |ig/m3.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the Indiana
sites from those tables include the following:
INDEM does not appear in Table 4-10. Its annual average concentration of
-.th
formaldehyde ranks 17 and its annual average concentration of acetaldehyde ranks
>nd
22" among NMP sites sampling carbonyl compounds.
12-20
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12.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde and
formaldehyde were created for INDEM. Annual averages could not be calculated for WPIN,
therefore, this site has no figures in this section. Figures 12-11 and 12-12 overlay INDEM's
minimum, annual average, and maximum concentrations onto the program-level minimum, first
quartile, median, average, third quartile, and maximum concentrations, as described in
Section 3.5.3.
Figure 12-11. Program vs. Site-Specific Average Acetaldehyde Concentration
INDEM
Concent ration (|
Program: 1st Quartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site: Site Average Site Minimum/Maximum
Figure 12-12. Program vs. Site-Specific Average Formaldehyde Concentration
INDEM
13
15
Concentration {|
Program: 1st Quartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site: Site Average Site Minimum/Maximum
12-21
-------
Observations from Figures 12-11 and 12-12 include the following:
Figure 12-11 shows that the annual average acetaldehyde concentration for
INDEM is less than both program-level average concentration and median
concentration. In fact, INDEM's annual average is just greater than the program-
level first quartile (or 25th percentile). The maximum concentration of
acetaldehyde measured at INDEM is considerably less than the maximum
concentration measured across the program. There were no non-detects of
acetaldehyde measured at INDEM or across the program.
Figure 12-12 shows that INDEM's annual average formaldehyde concentration is
less than the program-level average formaldehyde concentration but greater than
the program-level median concentration. The maximum concentration of
formaldehyde measured at INDEM is considerably less than the maximum
concentration measured across the program. There were no non-detects of
formaldehyde measured at INDEM or across the program.
12.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. INDEM has sampled carbonyl compounds since 2004; thus, Figures 12-13 and
12-4 present the annual statistical metrics for acetaldehyde and formaldehyde for INDEM,
respectively. The statistical metrics presented for assessing trends include the substitution of
zeros for non-detects. Although WPIN began sampling carbonyl compounds in 2007 and thus,
meets the criteria for a trends analysis to be performed, the lack of annual averages for 2011
prevents the analysis from being performed for this site.
12-22
-------
Figure 12-13. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at INDEM
ฃ 10
'ป.
2007 2008
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
Figure 12-14. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at INDEM
J 300
* 5th Percentile - Minimum Median - Maximum
95th Percentile
Average
12-23
-------
Observations from Figure 12-13 for acetaldehyde measurements at INDEM include the
following:
Although carbonyl compound sampling began in 2003 at INDEM, sampling did not
begin until June, which does not yield enough samples for the statistical metrics to be
calculated for 2003, based on the criteria specified in Section 3.5.4. Thus,
Figure 12-13 begins with 2004.
In addition, there was a 3-month gap in sampling between September and November
2005 at the INDEM site; therefore, no statistical metrics are presented for 2005.
The maximum acetaldehyde concentration shown (13.8 |ig/m3) was measured at
INDEM on June 14, 2004. Four additional concentrations measured at INDEM were
greater than 10 |ig/m3 (one in 2006 and three in 2008).
The average concentration of acetaldehyde decreased significantly from 2007 to
2008, although the maximum and 95th percentile increased for 2008. With the
exception of the minimum and 5th percentile, the statistical parameters decreased
significantly from 2008 to 2009. The average and median concentrations decreased
by more than half and the 95th percentile decreased by more than 80 percent during
this time. The carbonyl compound samplers were switched out in 2009, which seems
to have had a significant impact on the concentrations measured, particularly with
respect to formaldehyde, which is discussed in more detail below.
The statistical parameters for 2010 are similar in magnitude to the statistical
parameters for 2011.
There have been no non-detects of acetaldehyde measured at INDEM over the years
shown.
Observations from Figure 12-14 for formaldehyde measurements at INDEM include the
following:
Five formaldehyde concentrations greater than 400 |ig/m3 were measured in the
summer of 2008 (ranging from 414 |ig/m3to 499 |ig/m3). While these are extremely
high values of formaldehyde, concentrations of formaldehyde have been historically
high at this site, as shown by the statistics in Figure 12-14. There have been 25
measurements of formaldehyde greater than 100 |ig/m3 measured at INDEM, not
including the excluded years (2003 and 2005).
Prior to 2009, the maximum concentration for each year is greater than 100 |ig/m3.
Further, the median concentrations for years prior to 2008 are greater than 30 |ig/m3,
indicating that at least half of the concentrations were greater than 30 |ig/m3.
12-24
-------
Although the average concentration doubled from 2007 to 2008, the median
concentration decreased by more than half. This means that although the magnitude
of the outliers is driving the average concentration upward, there were a larger
number of concentrations at the lower end of the range as well. For 2008, 40 percent
of measurements were less than 5 |ig/m3; for the years prior to 2008, the number of
measurements less than 5 |ig/m3 ranged from none (2006) to two (2004).
All the statistical metrics decreased significantly for 2009 and the years that follow.
The average concentration for 2009 is 2.58 |ig/m3 and the average continued to
decrease thereafter (although the differences are not statistically significant). In
contrast to the previous bullet, the number of measurements greater than 5 |ig/m3
ranged from one to two for each year between 2009 and 2011.
INDEM's formaldehyde concentrations have historically been higher than any other
NMP site sampling carbonyl compounds. During the summer PAMS season, which
begins on June 1, a state-owned multi-channel collection system was used at INDEM
to collect multiple samples per day. At the end of each PAMS season, sample
collection goes back to a state-owned single-channel collection system. The multi-
channel sampler used at INDEM during the PAMS season was replaced in 2009 and
their formaldehyde concentrations decreased substantially (as did their acetaldehyde
concentrations, but the difference is less dramatic). Given that the elevated
concentrations of formaldehyde were typically measured during the summer, this
sampler change could account for the differences in the concentrations for 2009-2011
compared to previous years. Thus, the elevated concentrations from previous years
were likely related to the multi-channel collection equipment and may not reflect the
actual levels in ambient air. However, concentrations in the earlier years of sampling
must have still been higher based on the number of concentrations greater than 5
|ig/m3 before and after 2009, as discussed in the previous bullets.
12.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each Indiana monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
12.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Indiana monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
12-25
-------
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
12.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Indiana sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 12-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
Table 12-6. Risk Approximations for the Indiana Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(jig/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Gary, Indiana - INDEM
Acetaldehyde
Formaldehyde
0.0000022
0.000013
0.009
0.0098
57/57
57/57
1.27
ฑ0.13
2.30
ฑ0.27
2.79
29.88
0.14
0.23
Indianapolis, Indiana - WPIN
Acetaldehyde
Formaldehyde
0.0000022
0.000013
0.009
0.0098
51/51
51/51
NA
NA
NA
NA
NA
NA
NA = Not available due to the criteria for calculating an annual average.
12-26
-------
Observations for the Indiana sites from Table 12-6 include the following:
The annual average concentration of formaldehyde for INDEM is greater than the
annual average concentration of acetaldehyde.
The cancer risk approximation for formaldehyde is an order of magnitude higher than
the cancer risk approximation for acetaldehyde for INDEM.
None of the pollutants of interest for INDEM have noncancer hazard approximations
greater than 1.0, indicating that no adverse health effects are expected from these
individual pollutants.
Cancer risk and noncancer hazard approximations could not be calculated for the
pollutants of interest for WPIN because annual averages are not available.
12.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 12-7 and 12-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 12-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 12-6. Table 12-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations, also calculated from annual averages provided in
Table 12-6.
The pollutants listed in Tables 12-7 and 12-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 12.3, INDEM and WPIN sampled for carbonyl compounds only. In addition, the cancer
risk and noncancer hazard approximations are limited to those pollutants with enough data to
meet the criteria for annual averages to be calculated; thus, cancer risk and noncancer hazard
approximations were not calculated for WPIN. A more in-depth discussion of this analysis is
provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this
analysis may help policy-makers prioritize their air monitoring activities.
12-27
-------
Table 12-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Indiana Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Cancer Risk
Approximation
Pollutant (in-a-million)
Gary, Indiana (Lake County) - INDEM
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
Coke Oven Emissions, PM
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Trichloroethylene
231.53
157.04
107.50
100.19
33.43
29.96
29.83
4.72
2.39
2.23
Coke Oven Emissions, PM
Formaldehyde
Hexavalent Chromium, PM
Benzene
Naphthalene
Arsenic, PM
1,3 -Butadiene
Nickel, PM
Ethylbenzene
Cadmium, PM
3.31E-02
2.04E-03
1.81E-03
1.81E-03
1.01E-03
9.93E-04
8.99E-04
6.66E-04
2.69E-04
2.63E-04
Formaldehyde 29.88
Acetaldehyde 2.79
Indianapolis, Indiana (Marion County) - WPIN
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Tetrachloroethylene
Dichloromethane
Trichloroethylene
POM, Group 2b
489.79
356.47
217.73
205.36
67.18
34.96
14.44
7.84
6.85
6.52
Formaldehyde
Benzene
1,3 -Butadiene
Hexavalent Chromium, PM
Naphthalene
Arsenic, PM
POM, Group 3
POM, Group 2b
Ethylbenzene
Nickel, PM
4.63E-03
3.82E-03
2.02E-03
1.23E-03
1.19E-03
1.10E-03
6.97E-04
5.74E-04
5.44E-04
4.59E-04
to
to
oo
-------
Table 12-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Indiana Monitoring Sites
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions (County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Gary, Indiana (Lake County) - INDEM
Toluene
Xylenes
Methanol
Ethylene glycol
Hexane
Benzene
Formaldehyde
Hydrochloric acid
Ethylbenzene
Acetaldehyde
676.97
528.24
315.13
271.89
231.90
231.53
157.04
153.19
107.50
100.19
Acrolein
Manganese, PM
Lead, PM
Cyanide Compounds, gas
Formaldehyde
Nickel, PM
Arsenic, PM
1,3 -Butadiene
Cadmium, PM
Acetaldehyde
503,495.00
468,665.08
109,768.53
36,721.25
16,024.72
15,405.79
15,399.37
14,981.21
14,626.32
11,131.89
Formaldehyde 0.23
Acetaldehyde 0.14
Indianapolis, Indiana (Marion County) - WPIN
Toluene
Xylenes
Methanol
Ethylene glycol
Benzene
Hydrochloric acid
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
1,373.22
935.63
684.51
504.44
489.79
460.45
356.47
269.35
217.73
205.36
Acrolein
Formaldehyde
1,3 -Butadiene
Hydrochloric acid
Acetaldehyde
Arsenic, PM
Benzene
Naphthalene
Lead, PM
Nickel, PM
1,220,725.02
36,374.58
33,589.47
23,022.60
22,818.28
17,017.69
16,326.44
11,654.54
11,113.23
10,619.54
to
to
VO
-------
Observations from Table 12-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the three highest emitted pollutants
with cancer UREs in both Marion and Lake County, although the quantity emitted is
roughly twice as high in Marion County.
Coke oven emissions, formaldehyde, and hexavalent chromium are the pollutants
with the highest toxicity-weighted emissions (of the pollutants with cancer UREs) for
Lake County. Formaldehyde, benzene, and 1,3-butadiene are the pollutants with the
highest toxicity-weighted emissions for Marion County.
Six of the highest emitted pollutants in both Lake and Marion County also have the
highest toxicity-weighted emissions (although the pollutants are not the same between
the counties).
While several metals (arsenic, cadmium, hexavalent chromium, and nickel) are
among the pollutants with the highest toxicity-weighted emissions for both counties,
none of these are among the highest emitted pollutants for either county. This
demonstrates that a pollutant does not have to be emitted in large quantities to be
toxic.
Acetaldehyde and formaldehyde are the only pollutants of interest for INDEM and
WPIN. Acetaldehyde and formaldehyde appear among the highest emitted pollutants
for both counties, with only formaldehyde appearing among the pollutants with the
highest toxicity-weighted emissions.
Observations from Table 12-8 include the following:
While toluene is the highest emitted pollutant with a noncancer RfC in both counties,
the toluene emissions in Marion County are nearly twice that of Lake County.
Xylenes and methanol are the second and third highest emitted pollutants in both
counties, with a similar pattern in the quantity emitted.
Acrolein is the pollutant with the highest toxicity-weighted emissions (of the
pollutants with noncancer RfCs) for both counties. Manganese and lead rank second
and third for Lake County, while formaldehyde and 1,3-butadiene rank second and
third for Marion County.
Only two of the highest emitted pollutants in Lake County also have the highest
toxicity-weighted emissions (formaldehyde and acetaldehyde). Several metals
(manganese, lead, nickel, arsenic, and cadmium) are among the pollutants with the
highest toxicity-weighted emissions for Lake County, although none of these appear
among the highest emitted pollutants.
Four of the highest emitted pollutants in Marion County also have the highest
toxicity-weighted emissions (formaldehyde, acetaldehyde, hydrochloric acid, and
benzene).
12-30
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12.6 Summary of the 2011 Monitoring Data for INDEM and WPIN
Results from several of the data treatments described in this section include the
following:
ปซป Two carbonyl compounds failed screens for WPIN and three failed screens for
INDEM.
ปซป The annual average concentration of formaldehyde is greater than the annual
average concentration of acetaldehyde for INDEM. Annual averages concentrations
could not be calculated for WPIN.
ปซป Concentrations of formaldehyde and acetaldehyde exhibit a decreasing trend at
INDEM.
12-31
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13.0 Site in Kentucky
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Kentucky, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
13.1 Site Characterization
This section characterizes the Kentucky monitoring site by providing geographical and
physical information about the location of the site and the surrounding area. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
site and assist in the interpretation of the ambient monitoring measurements.
The Kentucky monitoring site is located near Grayson Lake in northeast Kentucky.
Figure 13-1 is a composite satellite image retrieved from ArcGIS Explorer showing the
monitoring site in its rural location. Figure 13-2 identifies nearby point source emissions
locations by source category, as reported in the 2008 NEI for point sources. Note that only
sources within 10 miles of the site are included in the facility counts provided in Figure 13-2. A
10-mile boundary was chosen to give the reader an indication of which emissions sources and
emissions source categories could potentially have a direct effect on the air quality at the
monitoring site. Further, this boundary provides both the proximity of emissions sources to the
monitoring site as well as the quantity of such sources within a given distance of the site. Sources
outside the 10-mile radius are still visible on the map, but have been grayed out in order to show
emissions sources just outside the boundary. Table 13-1 provides supplemental geographical
information such as land use, location setting, and locational coordinates.
13-1
-------
Figure 13-1. Grayson, Kentucky (GLKY) Monitoring Site
to
-------
Figure 13-2. NEI Point Sources Located Within 10 Miles of GLKY
Mote; Due to facility density and education, the total facilities
displayed may not represent all facilities within the area of interest,
Legend
ฉ GLKY NATTS site
10 mile radius
County boundary
Source Category Group (No. of Facilities)
f1 Aircraft Operations (1)
Brick Manufacturing & Structural Clay (2)
B Bulk Terminals/Bulk Plants (1)
F Food Processing/Agriculture (1)
* Hot Mix Asphalt Plant (1)
x Mine/Quarry (1)
? Miscellaneous Commercial/Industrial (1)
13-3
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Table 13-1. Geographical Information for the Kentucky Monitoring Site
Site
Code
GLKY
AQS Code
21-043-005
Location
Gray son
County
Carter
Micro- or
Metropolitan
Statistical Area
Not in an MSA
Latitude
and
Longitude
38.238333,
-82.988333
Land Use
Residential
Location
Setting
Rural
Additional Ambient Monitoring Information1
Carbonyl compounds, O3, Meteorological parameters,
PMio, PM10 Speciation, PM25, andPM25 Speciation
BOLD ITALICS = EPA-designaled NATTS Site
-------
Grayson Lake is located in northeast Kentucky, south of the town of Grayson, and west
of the Huntington-Ashland, WV-KY MSA. The Little Sandy River feeds into Grayson Lake,
which is a U.S. Army Corps of Engineers-managed project, and part of the Kentucky State Parks
system. The lake is narrow and winding, as shown in Figure 13-1, with sandstone cliffs rising to
up to 200 feet above the lake surface (KY, 2013 and ACE, 2013). The closest road to the
monitoring site is a service road feeding into Camp Grayson. This site serves as the Grayson
Lake NATTS site. Figure 13-2 shows that few point sources surround GLKY and that most of
them are on the outer periphery of the 10-mile radius around GLKY. This is not surprising given
the rural nature of the area and that Grayson Lake is located roughly in the center of the 10-mile
radius in Figure 13-2, oriented from northeast to southwest. Sources within 10 miles of GLKY
are involved in aircraft operations, brick and structural clay manufacturing, food processing, and
mining, among others.
Table 13-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Kentucky monitoring site. Table 13-2 includes county-level
population and vehicle registration information. Table 13-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within the monitoring site's residing county. In addition, the population within 10 miles
of the site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding the monitoring site. Table 13-2 also
contains traffic volume information. Finally, Table 13-2 presents the county-level daily VMT for
Carter County.
Table 13-2. Population, Motor Vehicle, and Traffic Information for the Kentucky
Monitoring Site
Site
GLKY
Estimated
County
Population1
27,586
County-level
Vehicle
Registration2
32,398
Vehicles per
Person
(Registration:
Population)
1.17
Population
within 10
miles3
14,610
Estimated
10-mile
Vehicle
Ownership
17,159
Annual
Average
Daily
Traffic4
428
County-
level
Daily
VMT5
1,084,000
Bounty-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Kentucky Transportation Cabinet (KYTC, 2012a)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2009 data from the Kentucky Transportation Cabinet (KYTC, 2009)
5County-level VMT reflects 2011 data from the Kentucky Transportation Cabinet (KYTC, 2012b)
BOLD ITALICS = EPA-designated NATTS Site
13-5
-------
Observations from Table 13-2 include the following:
The Carter County population is the second lowest compared to counties with NMP
sites (behind only UCSD in Union County, SD). The 10-mile population for GLKY is
also on the low side compared to other sites. The corresponding vehicle ownership
data mimicked these rankings. The rather low population and vehicle ownership
compared to other NMP sites is not surprising given the rural nature of the
surrounding area.
The vehicle-per-person ratio is among the higher ratios compared to other NMP sites.
The traffic data for GLKY is provided for the intersection of State Road 1496 with
Camp Webb Road, one of several secondary roads leading to Grayson Lake. This site
has the third lowest traffic volume among NMP sites.
The daily VMT for Carter County is the second lowest compared to other counties
with NMP sites (where VMT data were available), behind only Union County, SD.
13.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Kentucky on sample days, as well as over the course of the year.
13.2.1 Climate Summary
Kentucky experiences a continental climate, where conditions tend to be slightly cooler
and drier in the northeast portion of the state and warmer and wetter in the southwest portion.
Kentucky's mid-latitude location ensures an active weather pattern, in a convergence zone
between cooler air from the north and warm, moist air from the south. The state enjoys all four
seasons. Summers are persistently warm and humid; winters are cloudy but not harsh; and spring
and fall are considered pleasant. Precipitation is well distributed throughout the year, although
fall tends to be driest and spring wettest (NCDC, 2013).
13.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station to GLKY is located at Tri-State/Ml.
Ferguson Field Airport (WBAN 03860). Additional information about this weather station, such
as the distance between the site and the weather station, is provided in Table 13-3. These data
were used to determine how meteorological conditions on sample days vary from conditions
experienced throughout the year.
13-6
-------
Table 13-3. Average Meteorological Conditions near the Kentucky Monitoring Site
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Grayson, Kentucky - GLKY
Tri-St/MJ.
Ferguson Field
Airport
03860
(38.38, -82.56)
24.27
miles
58ฐ
(ENE)
Sample
Day
2011
65.3
ฑ4.4
65.7
ฑ1.8
55.6
ฑ4.1
56.1
ฑ1.7
45.7
ฑ4.6
46.5
ฑ1.8
50.7
ฑ4.0
51.2
ฑ1.6
72.6
ฑ3.3
73.4
ฑ1.3
1016.4
ฑ 1.5
1016.3
ฑ0.7
4.2
ฑ0.6
4.2
ฑ0.2
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Table 13-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 13-3 is the
95 percent confidence interval for each parameter. As shown in Table 13-3, average
meteorological conditions on sample days near GLKY were representative of average weather
conditions throughout the year.
13.2.3 Back Trajectory Analysis
Figure 13-3 is the composite back trajectory map for days on which samples were
collected at the GLKY monitoring site in 2011. Included in Figure 13-3 are four back trajectories
per sample day. Figure 13-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 13-3 and 13-4 represents 100 miles.
Observations from Figures 13-3 and 13-4 for GLKY include the following:
Back trajectories originated from a variety of directions at GLKY. An imaginary line
drawn north-south through the center of Figure 13-3 would show that a higher
number of trajectories originated from a direction with a westerly component than an
easterly component.
The farthest away a back trajectory originated was over southeast Minnesota, or just
greater than 600 miles away; however, the average trajectory length was 212 miles
and 86 percent of trajectories originated within 350 miles of the monitoring site.
Back trajectories originating to the west and northwest of GLKY account for nearly
40 percent of back trajectories, but are represented by two clusters in Figure 13-4.
One cluster (26 percent) includes back trajectories originating over Ohio and Indiana
while the other cluster (13 percent) includes longer back trajectories originating over
Illinois or farther to the west or northwest. Another nearly 40 percent of back
trajectories originated to the southwest of GLKY. This cluster trajectory includes
back trajectories of varying lengths. Fifteen percent of back trajectories originated to
the north-northwest to north-northeast of GLKY, as represented by the cluster
trajectory originating over Lake Erie. The cluster trajectory originating over Virginia
(10 percent) includes shorter trajectories originating to the east over West Virginia
and Virginia or longer trajectories originating to the southeast over North Carolina.
13-8
-------
Figure 13-3. 2011 Composite Back Trajectory Map for GLKY
Figure 13-4. Back Trajectory Cluster Map for GLKY
13-9
-------
13.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at the Tri-State/M. J. Ferguson
Field Airport near GLKY were uploaded into a wind rose software program to produce
customized wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind
directions using "petals" positioned around a 16-point compass, and uses different colors to
represent wind speeds.
Figure 13-5 presents a map showing the distance between the NWS station and GLKY,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 13-5 also presents three different wind roses for the
GLKY monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
Observations from Figure 13-5 for GLKY include the following:
The Tri-State/MJ. Ferguson Field weather station is located over 24 miles to the
east-northeast of GLKY and just across the state border in West Virginia.
The historical wind rose shows that calm winds were observed for more than
23 percent of the hourly measurements near GLKY. Winds from the south to
southwest to west make up the majority of observations near GLKY, particularly
those from south-southwest.
The wind patterns on the 2011 wind rose are similar to those on the historical wind
rose, but calm winds accounted for a slightly higher percentage of the wind
observations in 2011 (27 percent).
The sample day wind rose resembles both the historical and full-year wind roses,
although with fewer southerly winds and more northeasterly winds. This indicates the
wind conditions on sample days were generally representative of those experienced
throughout 2011 and historically.
13-10
-------
Figure 13-5. Wind Roses for the Tri-State/M. J. Ferguson Field Airport Weather Station
near GLKY
Distance between GLKY and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
13-11
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13.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for GLKY in order to allow
analysts and readers to focus on a subset of pollutants through the context of risk. Each
pollutant's preprocessed daily measurement was compared to its associated risk screening value.
If the concentration was greater than the risk screening value, then the concentration "failed the
screen." Pollutants of interest are those for which the individual pollutant's total failed screens
contribute to the top 95 percent of the site's total failed screens. In addition, if any of the NATTS
MQO Core Analytes measured by the monitoring site did not meet the pollutant of interest
criteria based on the preliminary risk-based screening, that pollutant was added to the list of site-
specific pollutants of interest. A more in-depth description of the risk-based screening process is
presented in Section 3.2.
Table 13-4 presents the results of the preliminary risk-based screening process for
GLKY. The pollutants that failed at least one screen and contributed to 95 percent of the total
failed screens for the monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. GLKY sampled for hexavalent chromium, PMio
metals, carbonyl compounds, PAHs, and VOCs.
Observations from Table 13-4 include the following:
GLKY sampled hexavalent chromium, VOCs, and PAHs throughout 2011, but
did not begin sampling metals through the NMP until May and carbonyl
compounds until August.
Fifteen pollutants failed screens for GLKY, including nine NATTS MQO Core
Analytes.
Ten pollutants were initially identified as pollutants of interest via the risk-based
screening process, of which six are NATTS MQO Core Analytes. Naphthalene
and nickel were added as pollutants of interest for GLKY because they are
NATTS Core Analytes, even though they did not contribute to 95 percent of the
total failed screens. Nine additional pollutants were added to GLKY's pollutants
of interest because they are NATTS MQO Core Analytes, even though they did
not fail any screens. These nine pollutants are not shown in Table 13-4 but are
shown in subsequent tables in the sections that follow.
Benzene and formaldehyde were detected in each VOC and carbonyl compound
sample, respectively, and failed 100 percent of screens. Other pollutants also
failed 100 percent of screens but were detected less frequently.
13-12
-------
Table 13-4. Risk-Based Screening Results for the Kentucky Monitoring Site
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Grayson, Kentucky - GLKY
Benzene
Carbon Tetrachloride
1,3-Butadiene
Arsenic (PM10)
Formaldehyde
Acet aldehyde
1 ,2-Dichloroethane
Acrylonitrile
Hexachloro- 1 , 3 -butadiene
Manganese (PM10)
1 , 1 ,2,2-Tetrachloroethane
Naphthalene
1 ,2-Dibromoethane
ฃ>-Dichlorobenzene
Nickel (PM10)
0.13
0.17
0.03
0.00023
0.077
0.45
0.038
0.015
0.045
0.005
0.017
0.029
0.0017
0.091
0.0021
Total
61
60
36
31
26
22
21
20
8
6
4
3
2
2
1
303
61
61
43
41
26
26
21
20
10
41
4
61
2
21
41
479
100.00
98.36
83.72
75.61
100.00
84.62
100.00
100.00
80.00
14.63
100.00
4.92
100.00
9.52
2.44
63.26
20.13
19.80
11.88
10.23
8.58
7.26
6.93
6.60
2.64
1.98
1.32
0.99
0.66
0.66
0.33
20.13
39.93
51.82
62.05
70.63
77.89
84.82
91.42
94.06
96.04
97.36
98.35
99.01
99.67
100.00
13.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Kentucky monitoring site. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for GLKY, where the data meet the applicable criteria.
Concentration averages for select pollutants are also presented graphically to illustrate how the
site's concentrations compare to the program-level averages, as presented in Section 4.1. In
addition, concentration averages for select pollutants are presented from previous years of
sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for GLKY are provided in Appendices J, L, M, N, and O.
13.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for the Kentucky site, as described in Section 3.1. The quarterly average of a particular pollutant
is simply the average concentration of the preprocessed daily measurements over a given
calendar quarter. Quarterly average concentrations include the substitution of zeros for all non-
detects. A site must have a minimum of 75 percent valid samples of the total number of samples
13-13
-------
possible within a given quarter for a quarterly average to be calculated. An annual average
includes all measured detections and substituted zeros for non-detects for the entire year of
sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Kentucky
monitoring site are presented in Table 13-5, where applicable. Note that concentrations of the
PAHs, metals, and hexavalent chromium for GLKY are presented in ng/m3 for ease of viewing.
Also note that if a pollutant was not detected in a given calendar quarter, the quarterly average
simply reflects "0" because only zeros substituted for non-detects were factored into the
quarterly average concentration.
Table 13-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Kentucky Monitoring Site
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Hg/m3)
2nd
Quarter
Average
(Hg/m3)
3rd
Quarter
Average
(jig/m3)
4th
Quarter
Average
(jig/m3)
Annual
Average
(jig/m3)
Grayson, Kentucky - GLKY
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Hexachloro- 1 , 3 -butadiene
Tetrachloroethylene
Trichloroethylene
26/26
20/61
61/61
43/61
61/61
15/61
21/61
26/26
10/61
30/61
4/61
NA
0
0.62
ฑ0.06
0.04
ฑ0.01
0.53
ฑ0.08
0.02
ฑ0.02
0.02
ฑ0.02
NA
0.01
ฑ0.02
0.06
ฑ0.02
0
NA
0.01
ฑ0.02
0.46
ฑ0.08
0.02
ฑ0.01
0.59
ฑ0.04
0.02
ฑ0.02
0.04
ฑ0.03
NA
0.02
ฑ0.02
0.04
ฑ0.02
0.01
ฑ0.01
NA
0.05
ฑ0.07
0.58
ฑ0.19
0.03
ฑ0.02
0.69
ฑ0.04
0.06
ฑ0.04
0.01
ฑ0.01
NA
0.02
ฑ0.02
0.02
ฑ0.02
0.01
ฑ0.01
0.78
ฑ0.21
0.58
ฑ0.07
0.69
ฑ0.30
0.05
ฑ0.01
0.69
ฑ0.05
0.01
ฑ0.01
0.05
ฑ0.02
0.77
ฑ0.25
0.01
ฑ0.01
0.03
ฑ0.02
0.01
ฑ0.01
NA
0.16
ฑ0.07
0.59
ฑ0.09
0.04
ฑ0.01
0.63
ฑ0.03
0.03
ฑ0.01
0.03
ฑ0.01
NA
0.01
ฑ0.01
0.04
ฑ0.01
0.01
ฑ0.01
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
13-14
-------
Table 13-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Kentucky Monitoring Site (Continued)
Pollutant
Vinyl Chloride
Arsenic (PM10)a
Benzo(a)pyrene a
Beryllium (PM10) a
Cadmium (PM10)a
Hexavalent Chromium a
Lead(PM10)a
Manganese (PM10)a
Naphthalene a
Nickel (PM10)a
#of
Measured
Detections
vs. # of
Samples
3/61
41/41
29/61
41/41
41/41
37/61
41/41
41/41
61/61
41/41
1st
Quarter
Average
(Ug/m3)
0.01
ฑ0.01
NA
0.04
ฑ0.03
NA
NA
0.01
ฑO.01
NA
NA
20.50
ฑ3.12
NA
2nd
Quarter
Average
(Ug/m3)
0.01
ฑ0.01
NA
0.01
ฑ0.01
NA
NA
0.01
ฑ0.01
NA
NA
12.78
ฑ3.26
NA
3rd
Quarter
Average
(Ug/m3)
0.01
ฑ0.01
0.50
ฑ0.15
0.01
ฑ0.01
0.01
ฑO.01
0.09
ฑ0.03
0.01
ฑO.01
2.01
ฑ0.82
2.73
ฑ0.84
12.89
ฑ3.19
0.28
ฑ0.07
4th
Quarter
Average
(Ug/m3)
0
0.50
ฑ0.16
0.06
ฑ0.04
0.01
ฑ0.01
0.10
ฑ0.04
0.01
ฑ0.01
2.58
ฑ1.07
4.17
ฑ2.68
20.44
ฑ3.68
0.55
ฑ0.42
Annual
Average
(Ug/m3)
0.01
ฑ0.01
NA
0.03
ฑ0.01
NA
NA
0.01
ฑO.01
NA
NA
16.59
ฑ1.84
NA
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
Observations for GLKY from Table 13-5 include the following:
Annual average concentrations could not be calculated for the PMi0 metals because
sampling did not begin until May 2011. This is also true for the carbonyl compounds
because they did not begin sampling until August. However, Appendix L and
Appendix N provide the pollutant-specific average concentrations for all valid metals
and carbonyl compound samples collected over the entire sample period.
None of the annual average concentrations for the pollutants of interest for GLKY,
where they could be calculated, were greater than 1 |ig/m3. Carbon tetrachloride
(0.63 ฑ 0.03 |ig/m3) and benzene (0.59 ฑ 0.09 |ig/m3) have the highest annual average
concentrations for GLKY.
The fourth quarter average acrylonitrile concentration is significantly higher than the
other quarterly averages. This pollutant was not detected at all in the first quarter of
2011, was detected twice in the second quarter, and three times in the third. Thus, the
other 15 measured detections were measured during the fourth quarter. Sorting the
measurements in a descending order almost puts the data in order by descending date,
with the lowest concentrations measured earlier in the year and the highest
concentrations measured late in the year.
13-15
-------
The fourth quarter average concentration of benzene is similar to the other quarterly
averages in magnitude, but its confidence interval is much larger. The maximum
concentration of benzene was measured at GLKY on November 29, 2011
(2.63 |ig/m3). The next highest concentration measured during the fourth quarter was
less than half that concentration (0.906 |ig/m3).
Concentrations of benzo(a)pyrene were highest during the first and fourth quarters of
2011, as indicated by the quarterly averages. Five concentrations greater than
0.15 ng/m3 were measured at GLKY, two in January, one in October, and two in
December. Of the 29 measured detections of benzo(a)pyrene, eight were measured
during the first quarter, four were measured during the second quarter, four were
measured during the third quarter, and 13 were measured during the fourth quarter.
Similar to benzo(a)pyrene, the quarterly averages for naphthalene indicate that
concentrations tended to be lower during the warmer months and higher during the
colder months.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for GLKY from
those tables include the following:
GLKY appears in Table 4-9 for VOCs four times but does not appear in any of the
other tables.
GLKY has the third highest annual average concentration of acrylonitrile among
NMP sites sampling VOCs, behind only SPIL and UCSD.
GLKY ranked seventh for three VOCs: 1,2-dichloroethane, carbon tetrachloride, and
hexachl oro-1,3 -butadi ene.
13.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzene, benzo(a)pyrene,
1,3-butadiene, hexavalent chromium, and naphthalene were created for GLKY. Box plots were
not created for metals or carbonyl compounds because annual averages could not be calculated
for these pollutants. Figures 13-6 through 13-10 overlay the site's minimum, annual average, and
maximum concentrations onto the program-level minimum, first quartile, median, average, third
quartile, and maximum concentrations, as described in Section 3.5.3.
13-16
-------
Figure 13-6. Program vs. Site-Specific Average Benzene Concentration
GLKY
Program Max Concentration = 23.8 ug/ms
4 5
Concentration
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile SrdQuartile 4thQuartile Av(
n
Site Minimum/Maximum
;rage
10
Figure 13-7. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
0.75 1 1.25
Concentration (ng/mS)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 13-8. Program vs. Site-Specific Average 1,3-Butadiene Concentration
i Program Max Concentration = 9.51
L
2.5
1.5
Concentration
2.5
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
13-17
-------
Figure 13-9. Program vs. Site-Specific Average Hexavalent Chromium
Concentration
"-
D.I 5
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 13-10. Program vs. Site-Specific Average Naphthalene Concentration
Program Max Concentration =779 ng/m3
200 250 300
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 13-6 through 13-10 include the following:
Figure 13-6 is the box plot for benzene. Note that the program-level maximum
concentration (23.8 |ig/m3) is not shown directly on the box plot because the scale
of the box plot would be too large to readily observe data points at the lower end
of the concentration range. Thus, the scale has been reduced to 10 |ig/m3. This
box plot shows that the annual average concentration for GLKY is less than the
program-level average concentration as well as the program-level median
concentration. The annual average benzene concentration for GLKY is among the
lowest annual averages for this pollutant. There were no non-detects of benzene
measured at this site (or among sites sampling VOCs).
Figure 13-7 is the box plot for benzo(a)pyrene. Note that the first quartile for this
pollutant is zero and is not visible on this box plot. This box plot shows that the
annual average concentration for GLKY is less than the program-level average
concentration as well as the program-level median concentration. Several non-
detects of benzo(a)pyrene were measured at GLKY.
Similar to benzene, the scale for 1,3-butadiene has been adjusted in Figure 13-8 as
a result of a relatively large maximum concentration. The program-level
maximum concentration (9.51 |ig/m3) is not shown directly on the box plot in
order to allow for observation of data points at the lower end of the concentration
13-18
-------
range; thus, the scale has been reduced to 3.00 |ig/m3. Figure 13-8 shows that the
annual average concentration of 1,3-butadiene for GLKY is less than both the
program-level average and median concentrations. The maximum 1,3-butadiene
concentration measured at GLKY is just greater than the program-level third
quartile. Several non-detects of 1,3-butadiene were measured at GLKY.
Figure 13-9 is the box plot for hexavalent chromium. This box plot shows that the
annual average hexavalent chromium concentration for GLKY is just greater than
the program-level first quartile. The annual average hexavalent chromium
concentration for GLKY is among the lowest annual averages among NMP sites
sampling this pollutant. The maximum hexavalent chromium concentration
measured at GLKY is just greater than the program-level third quartile. Several
non-detects of hexavalent chromium were measured at GLKY.
Figure 13-10 is the box plot for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 500 ng/m3 to allow for observation of data points at the
lower end of the concentration range. Figure 13-10 shows that the annual average
concentration of naphthalene for GLKY is less than the program-level first
quartile. This site has the smallest range of naphthalene concentrations measured
among all sites sampling this pollutant. Nearly the entire range of measurements
is less than the program-level first quartile (only one measurement is greater than
the program-level first quartile). This site has the third-lowest annual average
concentration among NMP sites sampling PAHs.
13.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. Sampling at GLKY under the NMP began in 2008; therefore, a trends analysis was
not conducted for this site.
13.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
Kentucky monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
13-19
-------
13.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Kentucky monitoring site to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
13.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for GLKY and where annual average concentrations could
be calculated, risk was examined by calculating cancer risk and noncancer hazard
approximations. These approximations can be used as risk estimates for cancer and noncancer
effects attributable to the pollutants of interest. Although the use of these approximations is
limited, they may help identify where policy-makers may want to shift or confirm their air-
monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer risk and
noncancer hazard approximations are calculated and what limitations are associated with them.
Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer hazard
approximations are presented in Table 13-6, where applicable. Cancer risk approximations are
presented as probabilities while the noncancer hazard approximations are ratios and thus, unitless
values.
13-20
-------
Table 13-6. Risk Approximations for the Kentucky Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Grayson, Kentucky - GLKY
Acetaldehyde
Acrylonitrile
Arsenic (PM10)a
Benzene
Benzo(a)pyrene a
Bery Ilium (PM10)a
1,3 -Butadiene
Cadmium (PM10) a
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Hexachloro- 1 , 3 -butadiene
Hexavalent Chromium a
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0043
0.0000078
0.00176
0.0024
0.00003
0.0018
0.000006
0.000026
0.000013
0.000022
0.012
0.000034
0.00048
0.00000026
0.0000048
0.0000088
0.009
0.002
0.000015
0.03
_
0.00002
0.002
0.00001
0.1
0.098
2.4
0.0098
0.09
0.0001
0.00015
0.00005
0.003
0.00009
0.04
0.002
0.1
26/26
20/61
41/41
61/61
29/61
41/41
43/61
41/41
61/61
15/61
21/61
26/26
10/61
37/61
41/41
41/41
61/61
41/41
30/61
4/61
3/61
NA
0.16
ฑ0.07
NA
0.59
ฑ0.09
0.01
ฑ0.01
NA
0.04
ฑ0.01
NA
0.63
ฑ0.03
0.03
ฑ0.01
0.03
ฑ0.01
NA
0.01
ฑ0.01
O.01
ฑ0.01
NA
NA
0.02
ฑ0.01
NA
0.04
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
NA
10.93
NA
4.57
0.05
NA
1.07
NA
3.75
0.72
NA
0.30
0.11
NA
0.56
NA
0.01
0.02
0.01
NA
0.08
NA
0.02
_
NA
0.02
NA
0.01
O.01
0.01
NA
0.01
O.01
NA
NA
0.01
NA
0.01
O.01
0.01
NA = Not available due to the criteria for calculating an annual average.
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 13-5.
13-21
-------
Observations for GLKY from Table 13-6 include the following:
The pollutants of interest with the highest annual average concentrations for GLKY
are carbon tetrachloride, benzene, and acrylonitrile.
The pollutants with the highest cancer risk approximations for GLKY are
acrylonitrile, benzene, and carbon tetrachloride. Only one other pollutant of interest
for GLKY has a cancer risk approximation greater than 1.0 in-a-million
(1,3-butadiene).
All of the noncancer hazard approximations for the pollutants of interest for GLKY
are considerably less than an HQ of 1.0 (0.08 or less), indicating that no adverse
health effects are expected from these individual pollutants. The highest noncancer
hazard approximation was calculated for acrylonitrile.
Annual averages, and therefore cancer risk and noncancer hazard approximations,
could not be calculated for the metal and carbonyl compound pollutants of interest.
13.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 13-7 and 13-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 13-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 13-6. Table 13-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 13-6.
13-22
-------
Table 13-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Kentucky Monitoring Site
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Grayson, Kentucky (Carter County) - GLKY
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
POM, Group 2b
Dichloromethane
POM, Group 6
POM, Group la
26.56
15.19
11.80
9.53
3.03
2.06
0.40
0.25
0.04
0.02
Benzene
Formaldehyde
1,3 -Butadiene
Naphthalene
POM, Group 2b
Hexavalent Chromium, PM
Ethylbenzene
POM, Group 3
Acetaldehyde
POM, Group 5a
2.07E-04
1.97E-04
9.09E-05
7.00E-05
3.56E-05
3.33E-05
2.95E-05
2.47E-05
2.10E-05
1.78E-05
Acrylonitrile
Benzene
Carbon Tetrachloride
1,3 -Butadiene
1 ,2-Dichloroethane
Naphthalene
Hexachloro- 1 , 3 -butadiene
Hexavalent Chromium
Benzo(a)pyrene
Trichloroethylene
10.93
4.57
3.75
1.07
0.72
0.56
0.30
0.11
0.05
0.02
OJ
to
-------
Table 13-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Kentucky Monitoring Site
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Grayson, Kentucky (Carter County) - GLKY
Toluene
Xylenes
Benzene
Methanol
Hexane
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Styrene
59.99
44.41
26.56
15.98
15.43
15.19
11.80
9.53
3.03
2.50
Acrolein
Formaldehyde
1,3 -Butadiene
Cyanide Compounds, gas
Acetaldehyde
Benzene
Naphthalene
Xylenes
Arsenic, PM
Propionaldehyde
52,572.66
1,549.95
1,514.80
1,335.64
1,058.92
885.42
686.00
444.15
138.10
111.83
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Naphthalene
Trichloroethylene
Tetrachloroethylene
Chloroform
Hexachloro- 1 ,3 -butadiene
Hexavalent Chromium
0.08
0.02
0.02
0.01
0.01
<0.01
<0.01
<0.01
0.01
0.01
OJ
to
-------
The pollutants listed in Tables 13-7 and 13-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 13.3, GLKY sampled for hexavalent chromium, carbonyl compounds, PMio metals,
PAHs, and VOCs. In addition, the cancer risk and noncancer hazard approximations are limited
to those pollutants with enough data to meet the criteria for annual averages to be calculated. As
mentioned in Section 13.5.2, because annual averages could not be calculated for the metals or
carbonyl compounds, cancer risk and noncancer hazard approximations were not calculated. A
more in-depth discussion of this analysis is provided in Section 3.5.5.3. Similar to the cancer risk
and noncancer hazard approximations, this analysis may help policy-makers prioritize their air
monitoring activities.
Observations from Table 13-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Carter County. The emissions for this county are low compared to
other counties with NMP sites.
Benzene, formaldehyde, and 1,3-butadiene are the pollutants with the highest
toxicity-weighted emissions (of the pollutants with cancer UREs) for Carter County.
Seven of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Carter County. Note that benzene and formaldehyde top both lists.
Acrylonitrile, which has the highest cancer risk approximation among the pollutants
of interest for GLKY, appears on neither emissions-based list. This is also true for
carbon tetrachloride, which has the highest annual average concentration and the third
highest cancer risk approximation for GLKY.
Benzene, 1,3-butadiene, and naphthalene appear on both emissions-based lists for
Carter County and have one of the 10 highest cancer risk approximations for this site.
Hexavalent chromium, which has the eighth highest cancer risk approximation, ranks
sixth for toxicity-weighted emissions but is not one of the highest emitted pollutants
in Carter County.
Three POM Groups appear among the highest emitted pollutants (POM, Groups la,
2b, and 6). Three POM Groups also appear among the pollutants with the highest
toxicity-weighted emissions (POM, Groups 2b, 3, and 5a). Benzo(a)pyrene, a
13-25
-------
pollutant of interest for GLKY, is part of POM Group 5a. Several pollutants, such
acenaphthene, benzo(e)pyrene, and fluorene, are measured using Method TO-13 and
are part of POM, Group 2b, which appears on both emissions-based lists. Several
other pollutants, such benzo(a)anthracene and indeno(l,2,3-cd)pyrene, are also
measured using Method TO-13 and are part of POM, Group 6, which is one of the
highest emitted "pollutants" in Carter County.
Observations from Table 13-8 include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs in Carter County.
The pollutant with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) is acrolein. Although acrolein was sampled for at GLKY, this
pollutant was excluded from the pollutants of interest designation, and thus
subsequent risk-based screening evaluations, due to questions about the consistency
and reliability of the measurements, as discussed in Section 3.2. Acrolein does not
appear among Carter County's highest emitted pollutants.
Five of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Carter County.
Acrylonitrile, which has the highest noncancer hazard approximation among the
pollutants of interest for GLKY, appears on neither emissions-based list. Conversely,
benzene and 1,3-butadiene appear on all three lists.
13.6 Summary of the 2011 Monitoring Data for GLKY
Results from several of the data treatments described in this section include the
following:
*ป* Fifteen pollutants, including nine NA TTS MQO Core Analytes, failed screens for
GLKY.
ปซป None of the annual average concentrations of the pollutants of interest for GLKY,
where they could be calculated, were greater than 1 jug/m .
ปซป GLKY had the third highest annual average concentration of acrylonitrile among
NMP sites sampling VOCs.
ปซป GLKY had the smallest range of naphthalene concentrations measured among all
NMP sites sampling this pollutant.
ปซป Because sampling for PMw metals and car bony I compounds did not begin until
May 2011 and August 2011, respectively, annual average concentrations could not be
calculated for these pollutants.
13-26
-------
14.0 Site in Massachusetts
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Massachusetts, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
14.1 Site Characterization
This section characterizes the BOMA monitoring site by providing geographical and
physical information about the location of the site and the surrounding area. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
site and assist in the interpretation of the ambient monitoring measurements.
The BOMA monitoring site is located in Boston. Figure 14-1 is a composite satellite
image retrieved from ArcGIS Explorer showing the monitoring site in its urban location.
Figure 14-2 identifies nearby point source emissions locations by source category, as reported in
the 2008 NEI for point sources. Note that only sources within 10 miles of the site are included in
the facility counts provided in Figure 14-2. A 10-mile boundary was chosen to give the reader an
indication of which emissions sources and emissions source categories could potentially have a
direct effect on the air quality at the monitoring site. Further, this boundary provides both the
proximity of emissions sources to the monitoring site as well as the quantity of such sources
within a given distance of the site. Sources outside the 10-mile radius are still visible on the map,
but have been grayed out in order to show emissions sources just outside the boundary.
Table 14-1 provides supplemental geographical information such as land use, location setting,
and locational coordinates.
14-1
-------
Figure 14-1. Boston, Massachusetts (BOMA) Monitoring Site
-------
Figure 14-2. NEI Point Sources Located Within 10 Miles of BOMA
?nd
SOMANATTSsite
10 mile radius
/V 7riQ'0"W
Note: Due to facility density and collocation, the total facilities
displayed may not represent a II facilities within the area of interest.
County boundary
e
B
C
e
e
I
E
I
*
Source Category Group (No. of Facilities)
$1 Aerospace/Aircraft Manufacturing (1)
v Air-conditioning/Refrigeration (3)
-t< Aircraft Operations (18)
0 Auto Body Shop/Painters (1)
A Automobile/Truck Manufacturing (1)
Bakery (4)
Bulk Terminals/Bulk Plants (7)
Chemical Manufacturing (1)
Concrete Batch Plant (1)
Dry Cleaning (2)
Electrical Equipment (3)
Electricity Generation via Combustion (8) ^
Electroplating. Plating, Polishing, Anodizing, and Coloring (4) p
ฉ Fabricated Metal Products (5) A^
F Food Processing/Agriculture (1) >
n Furniture Plant (1)
f Gasoline/Diesel Service Station (2)
ffl Hospital (4)
Hot Mix Asphalt Plant (2)
Institutional - school (39)
Iron and Steel Foundry (1)
Laboratory (2)
Landfill (1)
L Large Appliance Manufacturing (1)
V Mineral Products (1)
? Miscellaneous Commercial/Industrial (38)
M Miscellaneous Manufacturing (6)
H Municipal Waste Combustor(l)
Pharmaceutical Manufacturing (1)
Printing/Publishing (1)
Pulp and Paper PlanlWood Products (1)
Rubber and Miscellaneous Plastics Products (2)
ii. Ship Building and Repairing (2)
> Solid Waste Disposal - Commercial/Institutional (2)
S Surface Coating (3)
Tt Telecommunications (4)
1 Wastewater Treatment {2)
14-3
-------
Table 14-1. Geographical Information for the Massachusetts Monitoring Site
Site
Code
BOMA
AQS Code
25-025-0042
Location
Boston
County
Suffolk
Micro- or
Metropolitan
Statistical Area
Boston-
Cambridge-
Quincy, MA-NH
MSA (Boston Div)
Latitude
and
Longitude
42.32944,
-71.0825
Land Use
Commercial
Location
Setting
Urban/City
Center
Additional Ambient Monitoring Information1
Lead (TSP), CO, VOCs, SO2, NO, NO2, NOX,
PAMS/NMOCs, Carbonyl compounds, O3,
Meteorological parameters, PM10, Black carbon,
PM2 5, PM2 5 Speciation.
BOLD ITALICS = EPA-designated NATTS Site
-------
The BOMA monitoring site is located at Dudley Square in Roxbury, a southwest
neighborhood of Boston and is the Roxbury NATTS site. The surrounding area is commercial as
well as residential, as shown in Figure 14-1. The monitoring site is approximately 1.25 miles
south of 1-90 and 1 mile west of 1-93. The original purpose for the location of this site was to
measure population exposure to a city bus terminal located across the street from the monitoring
site. In recent years, the buses servicing the area were converted to compressed natural gas
(CNG). As Figure 14-2 shows, BOMA is located near a large number of point sources, with a
high density of sources located a few miles to the west, northwest, and north of the site. The
source categories with the highest number of emissions sources surrounding BOMA include
institutional facilities (schools); aircraft operations, which includes airports as well as small
runways, heliports, or landing pads; and electricity generating units (via combustion).
Table 14-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Massachusetts monitoring site. Table 14-2 includes county-level
population and vehicle registration information. Table 14-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within the monitoring site's residing county. In addition, the population within 10 miles
of the site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding the monitoring site. Table 14-2 also
contains traffic volume information for BOMA. Finally, Table 14-2 presents the county-level
daily VMT for Suffolk County.
Table 14-2. Population, Motor Vehicle, and Traffic Information for the Massachusetts
Monitoring Site
Site
BOMA
Estimated
County
Population1
730,932
County-level
Vehicle
Registration2
481,199
Vehicles per
Person
(Registration:
Population)
0.66
Population
within 10
miles3
1,671,730
Estimated
10-mile
Vehicle
Ownership
1,100,560
Annual
Average
Daily
Traffic4
31,400
County-
level Daily
VMT5
10,695,874
Bounty-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Massachusetts Registry of Motor Vehicles (MA
RMV, 2012)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2007 data from the Massachusetts DOT (MA DOT, 2007)
5County-level VMT reflects 2011 data for from the Massachusetts DOT (MA DOT, 2013)
BOLD ITALICS = EPA-designated NATTS Site
14-5
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Observations from Table 14-2 include the following:
The Suffolk County population is in the middle of the range compared to other
counties with NMP sites, while BOMA's 10-mile population is among the higher
10-mile populations (ranking 6th).
Similar to the populations, the Suffolk County vehicle registration is in the middle of
the range compared to other counties with NMP sites, while its 10-mile estimated
vehicle ownership is among the higher estimates (ranking 5th).
The vehicle-per-person ratio is the fourth lowest ratio when compared to other NMP
sites.
The traffic volume experienced near BOMA is in the middle of the range compared to
other NMP sites. The traffic estimate provided is for Melnea Cass Boulevard between
Washington Street and Harrison Avenue.
The daily VMT for Suffolk County is in the middle of the range compared to other
counties with NMP sites (where VMT data were available).
14.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Massachusetts on sample days, as well as over the course of the year.
14.2.1 Climate Summary
Boston's New England location ensures that the city experiences a fairly active weather
pattern. Storm systems frequently track across the region, bringing ample precipitation to the
area. The proximity to the Atlantic Ocean helps moderate temperatures, both in the summer and
the winter, while at the same time allowing winds to gust higher than they would farther inland.
Winds generally flow from the northwest in the winter and southwest in the summer. Coastal
storm systems called "Nor'easters," strong low pressure systems that produce heavy rain or snow
and winds up to hurricane strength along the Mid-Atlantic and northeast coastal states, often
produce the heaviest snowfalls for the area (Bair, 1992 and NOAA, 2013a).
14-6
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14.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station to BOMA is located at Logan International
Airport (WBAN 14739). Additional information about the Logan Airport weather station, such
as the distance between the site and the weather station, is provided in Table 14-3. These data
were used to determine how meteorological conditions on sample days vary from conditions
experienced throughout the year.
Table 14-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 14-3 is the
95 percent confidence interval for each parameter. As shown in Table 14-3, average
meteorological conditions on sample days at BOMA were representative of average weather
conditions throughout the year.
14.2.3 Back Trajectory Analysis
Figure 14-3 is the composite back trajectory map for days on which samples were
collected at the BOMA monitoring site in 2011. Included in Figure 14-3 are four back
trajectories per sample day. Figure 14-4 is the corresponding cluster analysis. An in-depth
description of these maps and how they were generated is presented in Section 3.5.2.1. For the
composite map, each line represents the 24-hour trajectory along which a parcel of air traveled
toward the monitoring site on a given sample day and time, based on an initial height of
50 meters AGL. For the cluster analysis, each line corresponds to a trajectory representative of a
given cluster of back trajectories. Each concentric circle around the site in Figures 14-3 and 14-4
represents 100 miles.
14-7
-------
Table 14-3. Average Meteorological Conditions near the Massachusetts Monitoring Site
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Boston, Massachusetts - BOMA
Logan
International
Airport
14739
(42.36, -71.01)
4.05
miles
42ฐ
(NE)
Sample
Day
2011
60.5
ฑ4.3
60.2
ฑ1.8
53.3
ฑ4.1
53.2
ฑ1.8
41.4
ฑ4.7
41.2
ฑ1.9
47.9
ฑ3.9
47.7
ฑ1.6
67.0
ฑ4.0
66.4
ฑ1.6
1014.5
ฑ2.0
1015.0
ฑ0.8
9.4
ฑ0.8
9.1
ฑ0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
oo
-------
Figure 14-3. 2011 Composite Back Trajectory Map for BOMA
Figure 14-4. Back Trajectory Cluster Map for BOMA
14-9
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Observations from Figures 14-3 and 14-4 include the following:
The composite back trajectory map shows that back trajectories originated from a
variety of directions at BOMA. The predominant direction of back trajectory origin is
to the northwest and south of the site, with the longest trajectories originating to the
west and northwest over Canada.
The 24-hour air shed domain for BOMA is similar in size to other NMP monitoring
sites. The farthest away a back trajectory originated was nearly 600 miles, over
Quebec, Canada, although back trajectories of similar length also originated over
southern Ontario, Canada. The average trajectory length was 251 miles and most back
trajectories (84 percent) originated within 400 miles of the monitoring site.
Nearly 40 percent of back trajectories originated within 200 miles of BOMA, as
indicated by the short cluster trajectory originating to the south of the site. This
cluster trajectory represents back trajectories originating from all directions of
relatively short length. It is important to recall that the HYSPLIT model includes both
distance and direction when determining clusters. Another 21 percent of back
trajectories originated to the north of BOMA, over the eastern Canadian provinces.
Seventeen percent of back trajectories originated to the south of BOMA, although this
cluster trajectory also includes back trajectories originating to the southwest over the
Mid-Atlantic states and Pennsylvania. The direction from which the least number of
back trajectories originated was east, at eight percent.
14.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Logan International Airport
near BOMA were uploaded into a wind rose software program to produce customized wind
roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions using
"petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 14-5 presents a map showing the distance between the NWS station and BOMA,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 14-5 also presents three different wind roses for the
BOMA monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
14-10
-------
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
Observations from Figure 14-5 for BOMA include the following:
The Logan International Airport weather station is located approximately 4 miles
northeast of BOMA. Note that the airport is located on a peninsula on Boston Harbor
with downtown Boston to the west, Chelsea to the north, and Winthrop to the east,
while the BOMA monitoring site is located west of South Boston, farther inland.
The historical wind rose shows that calm winds (< 2 knots) account for only three
percent of wind observations. Winds with a westerly component (south-southwest to
north-northwest) make up the bulk (nearly 60 percent) of winds greater than 2 knots.
The wind patterns shown on the 2011 wind rose resemble the historical wind patterns,
indicating that wind conditions during 2011 were typical of conditions experienced
historically near BOMA.
The sample day wind patterns resemble the full-year and historical wind patterns,
indicating that wind conditions on sample days were representative of those
experienced over the entire year and historically.
14-11
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Figure 14-5. Wind Roses for the Logan International Airport Weather Station near BOMA
Distance between BOMA and NWS Station
2001-2010 Historical Wind Rose
L vv^x /
,'VEsr
2011 Wind Rose
Sample Day Wind Rose
14-12
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14.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Massachusetts monitoring
site in order to allow analysts and readers to focus on a subset of pollutants through the context
of risk. Each pollutant's preprocessed daily measurement was compared to its associated risk
screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by the monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 14-4 presents the results of the preliminary risk-based screening process for
BOMA. The pollutants that failed at least one screen and contributed to 95 percent of the total
failed screens for the monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. BOMA sampled for PMio metals, PAHs, and
hexavalent chromium.
Table 14-4. Risk-Based Screening Results for the Massachusetts Monitoring Site
Pollutant
Screening
Value
(Hg/m3)
# of Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Boston, Massachusetts - BOMA
Naphthalene
Arsenic (PM10)
Manganese (PM10)
Nickel (PM10)
Acenaphthene
Fluorene
Hexavalent Chromium
0.029
0.00023
0.005
0.0021
0.011
0.011
0.000083
Total
54
48
12
5
1
1
1
122
61
60
60
60
61
61
54
417
88.52
80.00
20.00
8.33
1.64
1.64
1.85
29.26
44.26
39.34
9.84
4.10
0.82
0.82
0.82
44.26
83.61
93.44
97.54
98.36
99.18
100.00
Observations from Table 14-4 include the following:
Seven pollutants failed at least one screen for BOMA; of these, five are NATTS
MQO Core Analytes.
14-13
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Naphthalene accounted for nearly half of the total failed screens for BOMA.
Naphthalene and arsenic together account for nearly 85 percent of the total failed
screens.
Four pollutants, naphthalene and three PMio metals, were initially identified as
pollutants of interest for BOMA. Hexavalent chromium was added to the pollutants
of interest for BOMA because it is a NATTS MQO Core Analyte, even though it did
not contribute to 95 percent of the failed screens. Benzo(a)pyrene, beryllium,
cadmium, and lead were also added to BOMA's pollutants of interest because they
are NATTS MQO Core Analytes, even though they did not fail any screens. These
four pollutants are not shown in Table 14-4 but are shown in subsequent tables in the
sections that follow.
14.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Massachusetts monitoring site. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest for BOMA, where the data meet the applicable criteria.
Concentration averages for select pollutants are also presented graphically to illustrate how the
site's concentrations compare to the program-level averages, as presented in Section 4.1. In
addition, concentration averages for select pollutants are presented from previous years of
sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for BOMA are provided in Appendices M through O.
14.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for BOMA, as described in Section 3.1. The quarterly average of a particular pollutant is simply
the average concentration of the preprocessed daily measurements over a given calendar quarter.
Quarterly average concentrations include the substitution of zeros for all non-detects. A site must
have a minimum of 75 percent valid samples of the total number of samples possible within a
given quarter for a quarterly average to be calculated. An annual average includes all measured
detections and substituted zeros for non-detects for the entire year of sampling. Annual averages
were calculated for pollutants where three valid quarterly averages could be calculated and
where method completeness was greater than or equal to 85 percent, as presented in Section 2.4.
Quarterly and annual average concentrations for BOMA are presented in Table 14-5, where
applicable. Note that if a pollutant was not detected in a given calendar quarter, the quarterly
14-14
-------
average simply reflects "0" because only zeros substituted for non-detects were factored into the
quarterly average concentration.
Table 14-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Massachusetts Monitoring Site
Pollutant
#of
Measured
Detections vs.
# of Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Boston, Massachusetts - BOMA
Arsenic (PM10)
Benzo(a)pyrene
Beryllium (PM10)
Cadmium (PM10)
Hexavalent Chromium
Lead (PM10)
Manganese (PM10)
Naphthalene
Nickel (PM10)
60/60
61/61
60/60
60/60
54/61
60/60
60/60
61/61
60/60
0.26
ฑ0.06
0.15
ฑ0.04
0.03
ฑ0.03
0.13
ฑ0.02
0.02
ฑ0.01
3.18
ฑ1.25
2.77
ฑ0.85
55.51
ฑ11.52
1.29
ฑ0.21
0.45
ฑ0.14
0.11
ฑ0.03
0.01
ฑ0.01
0.15
ฑ0.03
0.03
ฑ0.01
3.50
ฑ1.10
4.58
ฑ1.15
55.96
ฑ 12.84
1.68
ฑ0.45
0.61
ฑ0.16
0.07
ฑ0.03
0.01
ฑ0.01
0.14
ฑ0.02
0.04
ฑ0.02
2.89
ฑ0.54
3.42
ฑ0.64
75.12
ฑ 16.68
1.39
ฑ0.43
0.38
ฑ0.11
0.12
ฑ0.02
0.01
ฑ0.01
0.10
ฑ0.02
0.02
ฑ0.01
2.74
ฑ0.71
3.11
ฑ0.75
53.83
ฑ 12.85
1.16
ฑ0.20
0.43
ฑ0.07
0.11
ฑ0.02
0.01
ฑ0.01
0.13
ฑ0.01
0.03
ฑ0.01
3.07
ฑ0.44
3.48
ฑ0.44
60.35
ฑ6.84
1.38
ฑ0.17
Observations for BOMA from Table 14-5 include the following:
Naphthalene is the pollutant with the highest annual average concentration by mass
(60.35 ฑ 6.84 ng/m3). The annual average concentrations for the remaining pollutants
of interest are at least an order of magnitude lower.
Of the PMio metals, manganese is the pollutant with the highest annual average
concentration (3.48 ฑ 0.44 ng/m3).
The first quarter concentration of beryllium (0.03 ฑ 0.03 ng/m3) is higher than the
other quarterly averages (each of them is less than 0.01 ng/m3). A review of the data
shows that the maximum concentration of beryllium was measured at BOMA on
January 21, 2011 (0.202 ng/m3). This measurement is an order of magnitude higher
than the next highest concentration measured at BOMA and the fifth highest
beryllium concentration measured across the program. In addition, all seven
beryllium concentrations greater than 0.01 ng/m3 were measured during the first
quarter of 2011 (four in January, one in February, and two in March).
14-15
-------
The first and second quarter average lead concentrations are higher than the other
quarterly averages and have larger confidence interval associated with them. A
review of the data shows that the maximum lead concentration was measured on
February 8, 2011 (10.4 ng/m3) although a similar concentration was also measured on
June 8, 2011 (10.3 ng/m3). These two measurements are twice the next highest
concentration (5.61 ng/m3). The median lead concentration for BOMA is 2.78 ng/m3.
The second quarter average manganese concentration is higher than the other
quarterly averages and has a larger confidence interval than the others. A review of
the data shows that the two maximum manganese concentrations were measured on
June 8, 2011 (9.48 ng/m3) and June 2, 2011 (7.08 ng/m3).
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for BOMA from
those tables include the following:
BOMA's annual average concentration of benzo(a)pyrene ranks seventh highest
among sites sampling PAHs.
BOMA's annual average concentration of beryllium ranks third highest among other
sites sampling PMio metals. BOMA also ranks fourth for nickel and fifth for
cadmium and lead.
BOMA's annual average concentration of hexavalent chromium ranks seventh
highest among sites sampling this pollutant.
14.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for arsenic, benzo(a)pyrene,
hexavalent chromium, lead, manganese, and naphthalene were created for BOMA. Figures 14-6
through 14-11 overlay the site's minimum, annual average, and maximum concentrations onto
the program-level minimum, first quartile, median, average, third quartile, and maximum
concentrations, as described in Section 3.5.3.
14-16
-------
Figure 14-6. Program vs. Site-Specific Average Arsenic (PMi0) Concentration
EC IV a
DL5
15
2 2.5
Concentration (ng/m3)
3.5
4.5
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 14-7. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
EC IV a
E
035 0.5 0.75 1 1.25 1.5 1.75
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 14-8. Program vs. Site-Specific Average Hexavalent Chromium Concentration
n-
3.1
Concentration (ng/m3)
0.25
:.=
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
14-17
-------
Figure 14-9. Program vs. Site-Specific Average Lead (PMi0) Concentration
BCtv'i
i:
15 20
Concentration (ng/m3)
35
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 14-10. Program vs. Site-Specific Average Manganese (PMi0) Concentration
EC IV A
; Program Max Concentration = 395 ng/m3
50
75
100
Concentration (ng/m3)
125
153
175
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average
Site Minimum/Maximum
2DD
Figure 14-11. Program vs. Site-Specific Average Naphthalene Concentration
BO IV A
Program Max Concentration =779 ng/m3
100
200 250 300
Concentration (ng/m3)
353
4"'
45:
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile SrdQuartile 4thQuartile Ave
Site Minimum/Maximum
rage
Observations from Figures 14-6 through 14-11 include the following:
Figure 14-6 shows that BOMA's annual average arsenic (PMio) concentration is
less than the program-level average concentration for arsenic (PMio) but is similar
to the program-level median concentration. The maximum concentration
measured at BOMA is considerably less than the maximum concentration
measured at the program level. There were no non-detects of arsenic measured at
BOMA.
14-18
-------
Figure 14-7 is the box plot for benzo(a)pyrene. Note that the first quartile for this
pollutant is zero and is not visible on this box plot. This box plot shows that the
annual average concentration for BOM A is greater than the program-level
average concentration and roughly equivalent to the program-level third quartile.
Figure 14-7 also shows that the maximum concentration measured at BOMA is
less than the maximum concentration measured across the program. There were
no non-detects of benzo(a)pyrene measured at BOMA.
Figure 14-8 is the box plot for hexavalent chromium. This figure shows that the
annual average concentration of hexavalent chromium for BOMA is just greater
than the program-level average concentration. The maximum concentration
measured at BOMA is less than the maximum concentration measured at the
program level. Several non-detects of hexavalent chromium were measured at
BOMA.
Figure 14-9 shows that the annual average lead (PMio) concentration for BOMA
is less than the program-level average concentration but greater than the program-
level median concentration. The maximum lead concentration measured at
BOMA is less than the maximum concentration measured at the program level.
There were no non-detects of lead at BOMA or across the program.
Figure 14-10 is the box plot for manganese (PMio). Note that the program-level
maximum concentration (395 ng/m3) is not shown directly on the box plot
because the scale of the box plot would be too large to readily observe data points
at the lower end of the concentration range. Thus, the scale has been reduced to
200 ng/m3. Figure 14-10 shows that the range of manganese concentrations
measured at BOMA is relatively small compared to the range of manganese
concentrations measured across the program. Although difficult to discern in
Figure 14-10, the annual average manganese (PMio) concentration for BOMA is
less than half the program-level average concentration and is less than the
program-level median concentration as well. The maximum manganese
concentration measured at BOMA is less than the program-level third quartile and
just greater than the program-level average concentration.
Similar to manganese, the program-level maximum concentration (799 ng/m3) is
not shown directly on the box plot for naphthalene in Figure 14-11 as the scale
has been reduced to 500 ng/m3 to allow for observation of data points at the lower
end of the concentration range. Figure 14-11 shows that the annual average
naphthalene concentration for BOMA is less than both the program-level average
and median concentrations. The maximum concentration measured at BOMA is
considerably less than the maximum concentration measured at the program level.
There were no non-detects of naphthalene measured at BOMA.
14-19
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14.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. BOMA has been sampling metals since 2003 and hexavalent chromium since
2005. Thus, Figures 14-12 through 14-15 present the annual statistical metrics for arsenic,
hexavalent chromium, lead, and manganese for BOMA, respectively. The statistical metrics
presented for calculating trends include the substitution of zeros for non-detects. BOMA began
sampling PAHs under the NMP in 2008; thus, the trends analysis was not conducted for the
PAHs because the 5 consecutive year criterion is not met.
Figure 14-12. Annual Statistical Metrics for Arsenic (PMio) Concentrations
Measured at BOMA
m"
E
Average Go nee n
T
2005
b . ,
dta
2006
SthPercentile
T
I
2007
- Minirrurr
"
Median
...<
T
r^H 1 =L
1 r~^
^m '^ ซ-
2008 2009 2010 2011
Year
Maximum 95th Percentile *ซ+.. Average
14-20
-------
Figure 14-13. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at BOMA
.a
5
S 0.3
8
8
&
S
< 0.2
2008
Year
5th Percentile - Minimum Median Maximum 95th Percentile "^--Average
Figure 14-14 Annual Statistical Metrics for Lead (PMio) Concentrations
Measured at BOMA
^
tration (ng/r
5 ;
rage Concen
g
<
5 -
2005
I
**m
*
2006
5th Percentile
MinilTLlIT
r
, 5-,
' 1 1
^
^MH H^H
t 1 aI i f ' I
2007 2008 2009 2010 2011
Year
Median - Maximum 95th Percentile ซซ*" Average
14-21
-------
Figure 14-15. Annual Statistical Metrics for Manganese (PMi0) Concentrations
Measured at BOMA
:DOS
Year
Minimum Median
Maximum
95thPercentile
* Average
Observations from Figure 14-12 for arsenic measurements at BOMA include the
following:
While PMio metals sampling began in 2003, data from that year were excluded from
this analysis because sampling did not begin until October. In addition, samples were
not collected in parts of April, May, September, and October 2004, which results in
the dataset not meeting the criteria specified in Section 3.5.4; thus, 2004 is also
excluded from Figure 14-12.
The maximum arsenic concentration shown was measured on July 5, 2008. The next
highest concentration measured is approximately half as high and was measured on
July 4, 2006.
Figure 14-12 shows that while there have been fluctuations in the average
concentration of arsenic at BOMA, the differences are not significant. The average
concentrations of arsenic have ranged from 0.36 ng/m3 (2010) to 0.61 ng/m3 (2008).
The median concentrations follow a similar trend but with less variation, ranging
from 0.34 ng/m3 (2010) to 0.46 ng/m3 (2008).
The minimum concentration measured for each year is greater than zero, indicating
that there have been no non-detects of arsenic measured at BOMA since 2005.
14-22
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Observations from Figure 14-13 for hexavalent chromium measurements at BOMA
include the following:
The maximum hexavalent chromium concentration was measured in 2008
(0.525 ng/m3). Less than 10 percent of hexavalent chromium concentrations measured
at BOMA are greater than 0.1 ng/m3. At least one concentration greater than
0.1 ng/m3 has been measured in each year since the onset of sampling, with 2005
having the most (eight) and 2011 having the least (one).
The range of measurements has varied each year, as indicated by both the maximum
concentration and the 95th percentile. The 95th percentile for 2008 is greater than the
maximum concentrations for 2010 and 2011.
The average concentration decreased significantly from 2006 to 2007, then increased
for 2008. A decreasing trend is also shown after 2008, although a slight increase is
shown for 2011.
The minimum and 5th percentile are both zero for each year of sampling, indicating
the presence of non-detects. The percentage of non-detects has varied between seven
percent (2006) to 26 percent (2009).
Observations from Figure 14-14 for lead measurements at BOMA include the following:
The maximum lead concentration shown (37.9 ng/m3) was measured in 2007. Only
three concentrations measured at BOMA are greater than 20 ng/m3 and these were
measured in 2005, 2007, and 2008.
The difference between the 5th and 95th percentiles for 2007 is nearly the same as
2010 and 2011, where the range of measurements is significantly smaller. This
indicates that the majority of measurements in 2007 fell within a relatively small
range, despite the maximum concentration shown.
The average concentration of lead exhibits an overall decreasing trend over the years
of sampling, reaching a minimum for 2010 and increasing slightly for 2011.
However, the variability in the measurements, particularly for 2007 and 2008, make it
difficult to draw definitive conclusions about this dataset.
The minimum concentration measured for each year is greater than zero, indicating
that there were no non-detects of lead measured at BOMA since 2005.
Observations from Figure 14-15 for manganese measurements at BOMA include the
following:
The maximum manganese concentration shown was measured on July 7, 2010
(12.3 ng/m3). Only three manganese concentrations measured at BOMA are greater
than 10 ng/m3, and these were measured in 2005, 2008, and 2010.
14-23
-------
Figure 14-15 shows that the average concentration of manganese decreased from
2005 to 2006. Between 2006 and 2011, the average and median concentrations of
manganese have changed relatively little. The average concentration for 2005 is
4.44 ng/m3, after which it ranges from 3.17 ng/m3 (2009) to 3.67 ng/m3 (2006).
Similarly, the median concentration for 2005 is 3.96 ng/m3, after which it ranges from
2.83 ng/m3 (2010) to 3.37 ng/m3 (2011).
The minimum concentration measured for each year is greater than zero, indicating
that there were no non-detects of manganese measured at BOMA since 2005.
14.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
BOMA monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
14.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Massachusetts monitoring site to the ATSDR MRLs, where available. As described in
Section 3.3, MRLs are noncancer health risk benchmarks and are defined for three exposure
periods: acute (exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and
chronic (exposures of 1 year or greater). The preprocessed daily measurements of the pollutants
of interest were compared to the acute MRLs; the quarterly averages were compared to the
intermediate MRLs; and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
14.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for BOMA and where annual average concentrations could
be calculated, risk was examined by calculating cancer risk and noncancer hazard
approximations. These approximations can be used as risk estimates for cancer and noncancer
effects attributable to the pollutants of interest. Although the use of these approximations is
limited, they may help identify where policy-makers may want to shift or confirm their air-
14-24
-------
monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer risk and
noncancer hazard approximations are calculated and what limitations are associated with them.
Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer hazard
approximations are presented in Table 14-6, where applicable. Cancer risk approximations are
presented as probabilities while the noncancer hazard approximations are ratios and thus, unitless
values.
Table 14-6. Risk Approximations for the Massachusetts Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)-1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections vs.
# of Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Boston, Massachusetts - BOMA
Arsenic (PM10)
Benzo(a)pyrene
Beiy Ilium (PM10)
Cadmium (PM10)
Hexavalent Chromium
Lead (PM10)
Manganese (PM10)
Naphthalene
Nickel (PM10)
0.0043
0.00176
0.0024
0.0018
0.012
0.000034
0.00048
0.000015
0.00002
0.00001
0.0001
0.00015
0.00005
0.003
0.00009
60/60
61/61
60/60
60/60
54/61
60/60
60/60
61/61
60/60
0.43
ฑ0.07
0.11
ฑ0.02
0.01
ฑ0.01
0.13
ฑ0.01
0.03
ฑ0.01
3.07
ฑ0.44
3.48
ฑ0.44
60.35
ฑ6.84
1.38
ฑ0.17
1.85
0.20
0.02
0.23
0.31
2.05
0.66
0.03
0.01
0.01
0.01
0.02
0.07
0.02
0.02
= a Cancer URE or Noncancer RfC is not available
Observations for BOMA from Table 14-6 include the following:
Naphthalene has the highest annual average concentration for BOMA. Manganese,
lead, and nickel also have annual average concentrations greater than 1.0 ng/m3.
Naphthalene and arsenic are the only pollutants of interest with cancer risk
approximations greater than 1.0 in-a-million (2.05 in-a-million and 1.85 in-a-million,
respectively).
None of BOMA's pollutants of interest have noncancer hazard approximations
greater than 1.0, indicating that no adverse health effects are expected due to these
individual pollutants.
14-25
-------
14.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 14-7 and 14-8 present a
risk-based evaluation of county-level emissions based on cancer and noncancer toxicity,
respectively. Table 14-7 presents the 10 pollutants with the highest emissions from the 2008
NEI, the 10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with
the highest cancer risk approximations (in-a-million), as calculated from the annual averages
provided in Table 14-6. Table 14-8 presents similar information, but identifies the 10 pollutants
with the highest noncancer hazard approximations (HQ), also calculated from annual averages
provided in Table 14-6.
The pollutants listed in Tables 14-7 and 14-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on the site's annual averages
are limited to those pollutants for which the site sampled. As discussed in Section 14.3, BOMA
sampled for PAHs, PMio metals, and hexavalent chromium. In addition, the cancer risk and
noncancer hazard approximations are limited to those pollutants with enough data to meet the
criteria for an annual average to be calculated. A more in-depth discussion of this analysis is
provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this
analysis may help policy-makers prioritize their air monitoring activities.
14-26
-------
Table 14-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Massachusetts Monitoring Site
-^
to
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Boston, Massachusetts (Suffolk County) - BOMA
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Methyl tert butyl ether
Nickel, PM
168.18
164.08
83.84
79.23
26.64
14.54
5.42
3.92
3.63
1.87
Formaldehyde
Benzene
Nickel, PM
1,3 -Butadiene
POM, Group 3
Naphthalene
Hexavalent Chromium, PM
POM, Group 2b
Arsenic, PM
Ethylbenzene
2.13E-03
1.31E-03
8.99E-04
7.99E-04
6.36E-04
4.94E-04
4.31E-04
3.45E-04
2.86E-04
2.10E-04
Naphthalene
Arsenic
Nickel
Hexavalent Chromium
Cadmium
Benzo(a)pyrene
Beryllium
2.05
1.85
0.66
0.31
0.23
0.20
0.02
-------
Table 14-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Massachusetts Monitoring Site
to
oo
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Boston, Massachusetts (Suffolk County) - BOMA
Toluene
Xylenes
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
Glycol ethers, gas
456.02
372.68
168.18
164.08
97.07
83.84
79.23
44.58
26.64
18.42
Acrolein
Nickel, PM
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Benzene
Naphthalene
Arsenic, PM
Xylenes
Cadmium, PM
313,612.93
20,816.71
16,743.22
13,322.42
8,803.49
5,606.08
4,847.85
4,440.73
3,726.77
2,204.94
Manganese
Arsenic
Lead
Naphthalene
Nickel
Cadmium
Beryllium
Hexavalent Chromium
0.07
0.03
0.02
0.02
0.02
0.01
<0.01
<0.01
-------
Observations from Table 14-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Suffolk County.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
cancer UREs) are formaldehyde, benzene, and nickel.
Seven of the highest emitted pollutants also have the highest toxi city-weighted
emissions.
Naphthalene and arsenic are the pollutants with the highest cancer risk
approximations for BOMA. Naphthalene ranks sixth among the highest emitted
pollutants and sixth for toxicity-weighted emissions. Arsenic ranks ninth on the list of
highest toxicity-weighted emissions but is not among the highest emitted.
Nickel, which has the third highest cancer risk approximation (albeit low) for BOMA,
appears on both emissions-based lists. Hexavalent chromium, which has the fourth
highest cancer risk approximation, ranks seventh on the list of highest toxicity-
weighted emissions but is not among the highest emitted.
POM, Group 2b ranks eighth for both quantity of emissions and toxicity-weighted
emissions. POM, Group 2b includes several PAHs sampled for at BOMA including
acenaphthene, fluoranthene, fluorene, and perylene. None of the PAHs included in
POM, Group 2b were identified as pollutants of interest for BOMA, although both
acenaphthene and fluorene failed screens (one each). Benzo(a)pyrene is part of POM,
Group 5a, which is not listed on either emissions-based list.
Observations from Table 14-8 include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs in Suffolk County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, nickel, and formaldehyde.
Five of the highest emitted pollutants also have the highest toxicity-weighted
emissions.
While nickel, arsenic, and cadmium are among the pollutants with the highest
toxicity-weighted emissions, no metals appear among the highest emitted pollutants.
Nickel, which has the second highest toxicity-weighted emissions (of those pollutants
with a noncancer RfC), has a negligible noncancer hazard approximation, as do the
remaining pollutants of interest for BOMA.
Manganese, which has the highest noncancer hazard approximation for BOMA
(albeit low), appears on neither emissions-based list.
14-29
-------
14.6 Summary of the 2011 Monitoring Data for BOMA
Results from several of the data treatments described in this section include the
following:
ปซป Seven pollutants failed screens for BOMA, of which five are NATTSMQO Core
Analytes. Naphthalene and arsenic account for a majority of the failed screens.
ปซป Naphthalene had the highest annual average concentration among the pollutants of
interest for BOMA.
ปซป Concentrations of the metal pollutants of interest have not changed significantly over
recent years.
14-30
-------
15.0 Sites in Michigan
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS and UATMP sites in Michigan, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
15.1 Site Characterization
This section characterizes the monitoring sites by providing geographical and physical
information about the locations of the sites and the surrounding areas. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
The DEMI, RRMI, and SWMI monitoring sites are located in the Detroit-Warren-
Livonia, MI MSA. Figures 15-1 through 15-3 are the composite satellite images retrieved from
ArcGIS Explorer showing the monitoring sites in their urban locations. Figure 15-4 identifies
nearby point source emissions locations by source category, as reported in the 2008 NEI for
point sources. Note that only sources within 10 miles of the sites are included in the facility
counts provided in Figure 15-4. A 10-mile boundary was chosen to give the reader an indication
of which emissions sources and emissions source categories could potentially have a direct effect
on the air quality at the monitoring sites. Further, this boundary provides both the proximity of
emissions sources to the monitoring sites as well as the quantity of such sources within a given
distance of the sites. Sources outside the 10-mile radii are still visible on the map, but have been
grayed out in order to show emissions sources just outside the boundary. Table 15-1 provides
supplemental geographical information such as land use, location setting, and locational
coordinates.
15-1
-------
Figure 15-1. Dearborn, Michigan (DEMI) Monitoring Site
-------
Figure 15-2. River Rouge, Michigan (RRMI) Monitoring Site
-------
Figure 15-3. Detroit, Michigan (SWMI) Monitoring Site
-------
Figure 15-4. NEI Point Sources Located Within 10 Miles of DEMI, RRMI, and SWMI
Legend
@ DEMI NATTS site
ฎ RRMI UATMP site
Source Category Group (No. of Facilities) |
': Air-condiliomrtg/Refrigeratfon (5)
-ff Aircraft Operations (9) [
I Asp
Gypsum Manufacturing (1}
Ho&pilal (2j
Hot MIK Asphalt Plant (2)
industrial Machinery and Equipment < 1}
InsDtulKHial - school (7)
iron and Steel Foundry (i)
Laboratory (4)
Landfill {1}
Lime Manufacturing 0)
Mine^Quarry (4)
Mineral Products 44)
Miscellaneous Commercial/Industrial (12)
Municipal V&ste Comtw&tor (1)
| County boundary
W
Oil and/or Gas Prwluclion (2)
Pelf oleum Refinery (1)
Pnnling^PublisrunBCl)
Rubber and Miscellaneous Plastics Products (3)
Secondary Metal Processing (1)
Solid ttfesle Disposal - Commercial'lnstituttonal (4)
Steel Mill (3)
Surface Coating (7)
Telecommunications (t)
Transportation Equipment (5)
Tiansportation and Marketing ol Petroleum Products (2)
V^stewater Treatmenl (1 )
Woodwork. Furniture. Milhvofk ฃ Wood Preserving <1>
15-5
-------
Table 15-1. Geographical Information for the Michigan Monitoring Sites
Site
Code
DEMI
RRMI
SWMI
AQS Code
26-163-0033
26-163-0005
26-163-0015
Location
Dearborn
River
Rouge
Detroit
County
Wayne
Wayne
Wayne
Micro- or
Metropolitan
Statistical Area
Detroit-Warren-
Livonia, MI MSA
(Detroit Div)
Detroit-Warren-
Livonia, MI MSA
(Detroit Div)
Detroit-Warren-
Livonia, MI MSA
(Detroit Div)
Latitude
and
Longitude
42.30754,
-83.14961
42.267222,
-83.132222
42.302778,
-83.106667
Land Use
Industrial
Industrial
Commercial
Location
Setting
Suburban
Suburban
Urban/City
Center
Additional Ambient Monitoring Information1
TSP Metals, Meteorological parameters, PM10, PM10
Speciation, PM2 5, and PM2 5 Speciation.
TSP Metals, Meteorological parameters, PM10, PM10
Manganese.
SO2, TSP Metals, Soil Index, VOCs, Meteorological
parameters, PM10, PM10 Manganese, PM25, and
PM2 5 Speciation
BOLD ITALICS = EPA-designated NATTS Site
-------
DEMI is located at Paul Costea Park in Dearborn, just southwest of Detroit, and is the
Detroit NATTS site. The surrounding area is both suburban and industrial in nature. Figure 15-1
shows that a freight yard is located just west of the site and a residential neighborhood is located
to the east. Industrial sources such as automobile and steel manufacturing facilities are also
located in the vicinity. The monitoring site lies between two heavily traveled roadways, 1-75 and
1-94.
RRMI is located at John Bilak Park in River Rouge, a southwestern suburb of Detroit,
less than 1 mile from the Detroit River and the U.S./Canadian border. The surrounding area is of
mixed usage, with residential properties surrounded by highly industrial ones (a freight yard is
located to the west of the site while the Port of Detroit is located just to the east and southeast,
just beyond the bottom right-hand side of Figure 15-2). This site is also downwind of a steel
manufacturing facility.
SWMI is located on the property of Southwestern High School in the city of Detroit. The
high school's track can be seen just west of the site marker in Figure 15-3. Interstate-75 runs
northeast-southwest less than 0.3 miles north of SWMI. The surrounding area is considered
commercial and the site lies approximately 1 mile north of Zug Island, a small, highly
industrialized area where the Rouge River empties into the Detroit River. This site is also less
than 1 mile northwest of the Detroit River and U.S./Canadian border.
Figure 15-4 shows that DEMI, RRMI, and SWMI are located within a few miles of each
other. Numerous point sources surround these sites. A cluster of sources is located just southwest
of DEMI. Another cluster of sources is located just north of RRMI. The source categories with
the most point sources within 10 miles of the sites include the aircraft operations source
category, which includes airports as well as small runways, heliports, or landing pads; bulk
terminals and bulk plants; electricity generation via combustion; fabricated metals facilities;
institutional facilities (schools); and surface coating facilities. Although difficult to discern in
Figure 15-4, the closest source to DEMI is involved in food processing; the closest source to
SWMI is involved in electricity generation via combustion; and the closest source to RRMI is
involved in asphalt processing/roofing manufacturing.
15-7
-------
Table 15-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Michigan monitoring sites. Table 15-2 includes county-level
population and vehicle registration information. Table 15-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 15-2 also
contains traffic volume information for each site. Finally, Table 15-2 presents the county-level
daily VMT for Wayne County.
Table 15-2. Population, Motor Vehicle, and Traffic Information for the Michigan
Monitoring Sites
Site
DEMI
RRMI
SWMI
Estimated
County
Population1
1,802,096
County-level
Vehicle
Registration2
1,334,752
Vehicles per
Person
(Registration:
Population)
0.74
Population
within 10
miles3
1,046,574
773,610
974,585
Estimated
10-mile
Vehicle
Ownership
775,162
572,987
721,842
Annual
Average
Daily
Traffic4
92,800
98,500
93,000
County-
level Daily
VMT5
42,804,737
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Michigan Department of State (MDS, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the Michigan DOT (MI DOT, 2011)
5County-level VMT reflects 2011 data for all public roads from the Michigan DOT (MI DOT, 2012)
BOLD ITALICS = EPA-designated NATTS Site
Observations from Table 15-2 include the following:
Wayne County's population and vehicle registration both rank eighth among counties
with NMP sites.
The vehicle-per-person ratio for these sites is the same and is in the bottom third
among NMP sites.
Among the Michigan monitoring sites, the 10-mile population is highest near DEMI
and lowest near RRMI. The 10-mile populations rank between 10th for DEMI and
21st for RRMI among NMP sites. The 10-mile estimated vehicle ownership rankings
are similar to the 10-mile population rankings.
15-8
-------
The traffic volumes near the Michigan sites are similar to each other and rank 14th,
15th, and 16th among NMP sites. Traffic for DEMI is provided for 1-94, between Ford
Plant Road and Rotunda Drive; traffic data for RRMI is for 1-75 between Outer Drive
and South Fort Street/M-85; and traffic data for SWMI is for 1-75 between Springwell
Street and Livernois Avenue.
The Wayne County daily VMT is the fifth highest VMT compared to other counties
with NMP sites (where VMT data were available).
15.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Michigan on sample days, as well as over the course of the year.
15.2.1 Climate Summary
Detroit is located in a region of active weather. Winters tend to be cold and wet, while
summers are generally mild, although temperatures exceeding 90ฐF are not uncommon. Two
major influences on the city's weather include the urbanization of the area and Lake St. Clair to
the east. The lake tends to keep the Detroit area warmer in the winter and cooler in the summer
than more inland areas. The urban heat island keeps the city warmer than outlying areas. Winds
are often breezy and flow from the southwest on average. Precipitation is fairly well distributed
throughout the year, with summer precipitation coming primarily in the form of showers and
thunderstorms. Approximately 30 inches of snow falls on average during winter (Bair, 1992 and
MSU, 2013).
15.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest these sites were
retrieved for 2011 (NCDC, 2011). The closest weather station to all three Detroit sites is located
at Detroit City Airport (WBAN 14822). Additional information about this weather station, such
as the distance between the sites and the weather station, is provided in Table 15-3. These data
were used to determine how meteorological conditions on sample days vary from conditions
experienced throughout the year.
15-9
-------
Table 15-3. Average Meteorological Conditions near the Michigan Monitoring Sites
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average 1
Scalar
Wind
Speed
(kt)
Dearborn, Michigan - DEMI
Detroit City Airport
14822
(42.41, -83.01)
9.70
miles
54ฐ
(NE)
Sample
Day
2011
56.8
ฑ5.2
58.0
ฑ2.2
49.7
ฑ4.9
50.8
ฑ2.0
40.2
ฑ4.4
40.9
ฑ 1.9
45.0
ฑ4.3
45.9
ฑ1.8
72.6
ฑ3.1
71.6
ฑ 1.2
1016.0
ฑ1.6
1015.6
ฑ0.7
6.7
ฑ0.7
6.7
ฑ0.3 |
River Rouge, Michigan - RRMI |
Detroit City Airport
14822
(42.41, -83.01)
15.73
miles
32ฐ
(NNE)
Sample
Day
2011
57.6
ฑ5.4
58.0
ฑ2.2
50.4
ฑ5.1
50.8
ฑ2.0
40.8
ฑ4.5
40.9
ฑ1.9
45.6
ฑ4.4
45.9
ฑ1.8
72.4
ฑ3.3
71.6
ฑ1.2
Detroit, Michigan - SWMI
Detroit City Airport
14822
(42.41, -83.01)
11.98
miles
34ฐ
(NE)
Sample
Day
2011
58.3
ฑ7.9
58.0
ฑ2.2
50.7
ฑ7.4
50.8
ฑ2.0
41.6
ฑ6.5
40.9
ฑ1.9
46.0
ฑ6.4
45.9
ฑ1.8
73.7
ฑ4.6
71.6
ฑ1.2
1016.1
ฑ 1.7
1015.6
ฑ0.7
1016.4
ฑ2.4
1015.6
ฑ0.7
6.6
ฑ0.7
6.7
ฑ0.3
5.9
ฑ0.9
6.7
ฑ0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Table 15-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 15-3 is the
95 percent confidence interval for each parameter. Average meteorological conditions on sample
days near the Detroit sites were generally representative of average weather conditions
experienced throughout the year, although Table 15-3 shows that the sample day temperature
averages for SWMI were most like the full-year averages while sample day temperature averages
for DEMI were the least like the full-year averages. This is interesting because SWMI sampled
on a l-in-12 day schedule and is the reason the sample day confidence intervals are larger than
the sample day confidence intervals for DEMI and RRMI, which sampled on a l-in-6 day
schedule. The bulk of the samples days for RRMI and DEMI are the same, although sampling at
RRMI did not begin until late January 2011.
15.2.3 Back Trajectory Analysis
Figure 15-5 is the composite back trajectory map for days on which samples were
collected at the DEMI monitoring site in 2011. Included in Figure 15-5 are four back trajectories
per sample day. Figure 15-6 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 15-5 and 15-6 represents 100 miles.
Figures 15-7 and 15-8 are the composite back trajectory map and corresponding cluster analysis
for RRMI. Figure 15-9 is the composite back trajectory map for SWMI but the cluster analysis
was not performed for this site because there were fewer than 30 sample days.
15-11
-------
Figure 15-5. 2011 Composite Back Trajectory Map for DEMI
Figure 15-6. Back Trajectory Cluster Map for DEMI
15-12
-------
Figure 15-7. 2011 Composite Back Trajectory Map for RRMI
Figure 15-8. Back Trajectory Cluster Map for RRMI
15-13
-------
Figure 15-9. 2011 Composite Back Trajectory Map for SWMI
Observations from Figures 15-5 through 15-9 for the Michigan sites include the
following:
The composite back trajectory maps for DEMI and RRMI are similar to each other in
trajectory distribution. This is expected given the close proximity to each other and
the similarities in sample days. The composite map for SWMI resembles the maps for
the other two sites but has roughly half the back trajectories because this site sampled
on a l-in-12 day sampling schedule rather than a l-in-6 day.
Back trajectories originated from a variety of directions at the Detroit monitoring
sites. Back trajectories originating to the east of the sites tended to be shorter in length
than trajectories from other directions.
The 24-hour air shed domain for DEMI was similar in size to RRMI. The farthest
away a back trajectory originated from DEMI was over central Ontario, Canada, or
greater than 675 miles away. While the farthest away a back trajectory originated
from RRMI was over South Dakota, or nearly 690 miles away, back trajectories of
similar length also originated over Ontario. The average trajectory lengths for these
two sites were just less than 270 miles. Approximately 88 percent of trajectories
originated within 450 miles of the sites.
15-14
-------
For SWMI, the air shed domain was slightly smaller than those for DEMI and RRMI,
with an average trajectory length of 243 miles with greater than 90 percent of back
trajectories originating within 450 miles of the site. The farthest away a back
trajectory originated was 553 miles over western Quebec, Canada.
The cluster analyses for DEMI and RRMI are similar to each other. The main
difference is how the HYSPLIT model grouped some of the shorter back trajectories
with a westerly component. Both cluster maps show that the bulk of the back
trajectories originated from a direction with a westerly component and that they
varied in length and therefore geographical origin. The cluster trajectories originating
over western Wisconsin, southern Indiana, Lake Erie, and Quebec, Canada are similar
in direction and origin for both sites although the percentages vary.
15.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at the Detroit City Airport were
uploaded into a wind rose software program to produce customized wind roses, as described in
Section 3.5.2.2. A wind rose shows the frequency of wind directions using "petals" positioned
around a 16-point compass, and uses different colors to represent wind speeds.
Figure 15-10 presents a map showing the distance between the NWS station and DEMI,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 15-10 also presents three different wind roses for the
DEMI monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figures 15-11 and 15-12 present the distance maps and
wind roses for RRMI and SWMI.
15-15
-------
Figure 15-10. Wind Roses for the Detroit City Airport Weather Station near DEMI
Distance between DEMI and NWS Station
2001-2010 Historical Wind Rose
IWEST
2011 Wind Rose
Sample Day Wind Rose
15-16
-------
Figure 15-11. Wind Roses for the Detroit City Airport Weather Station near RRMI
Distance between RRMI and NWS Station
2001-2010 Historical Wind Rose
MWS
Stilton
2011 Wind Rose
Sample Day Wind Rose
15-17
-------
Figure 15-12. Wind Roses for the Detroit City Airport Weather Station near SWMI
Distance between SWMI and NWS Station
2001-2010 Historical Wind Rose
NWS
lion
V'
IWEST
2011 Wind Rose
Sample Day Wind Rose
15-18
-------
Observations from Figures 15-10 through 15-12 include the following:
The NWS weather station at Detroit City Airport is the closest weather station to all
three monitoring sites. This weather station is located to the northeast of the sites and
ranges from 9.70 miles (DEMI) to 15.7 miles (RRMI) away from the sites. Most of
the city of Detroit lies between the weather station and the monitoring sites.
Because the Detroit City Airport weather station is the closest weather station to all
three sites, the historical and 2011 wind roses for DEMI are the same as those for
RRMI and SWMI.
The historical wind roses for the Detroit sites show that winds from a variety of
directions were observed, although winds from the northeast and southeast quadrants
were observed less frequently than winds from other directions. Calm winds
(< 2 knots) were observed for approximately 10 percent of the hourly measurements.
The wind patterns on the 2011 wind roses resemble the historical wind patterns,
although there were slightly fewer westerly to northwesterly winds and more
northerly and north-northeasterly winds. This resemblance indicates that conditions
during 2011 were consistent with those experienced historically.
The sample day wind roses for DEMI and RRMI generally resemble the full-year
wind rose, although there were fewer winds from the southwest quadrant and more
northerly to north-northeasterly winds on sample days.
The wind patterns on the sample day wind rose for SWMI differ from those on the
sample day wind roses for DEMI and RRMI. The calm rate is higher for SWMI and
winds from the north, west-southwest, and west account for nearly one-third of the
wind observations by themselves. Recall that the sample day wind rose for SWMI has
half the wind observations than the sample day wind roses for DEMI and RRMI due
to the sampling frequency.
15.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Michigan monitoring sites
in order to allow analysts and readers to focus on a subset of pollutants through the context of
risk. For each site, each pollutant's preprocessed daily measurement was compared to its
associated risk screening value. If the concentration was greater than the risk screening value,
then the concentration "failed the screen." Pollutants of interest are those for which the
individual pollutant's total failed screens contribute to the top 95 percent of the site's total failed
screens. In addition, if any of the NATTS MQO Core Analytes measured by each monitoring site
did not meet the pollutant of interest criteria based on the preliminary risk-based screening, that
pollutant was added to the list of site-specific pollutants of interest. A more in-depth description
of the risk-based screening process is presented in Section 3.2.
15-19
-------
Table 15-4 presents the results of the preliminary risk-based screening process for the
Michigan monitoring sites. The pollutants that failed at least one screen and contributed to
95 percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. All three Detroit
monitoring sites sampled for carbonyl compounds; in addition, DEMI sampled for VOCs, PAHs,
and hexavalent chromium.
Table 15-4. Risk-Based Screening Results for the Michigan Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
# of Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Dearborn, Michigan - DEMI
Acet aldehyde
Formaldehyde
Benzene
Carbon Tetrachloride
Naphthalene
1,3-Butadiene
Ethylbenzene
Acenaphthene
Fluorene
1 ,2-Dichloroethane
Fluoranthene
Hexavalent Chromium
Dichloromethane
Benzo(a)pyrene
ฃ>-Dichlorobenzene
Hexachloro- 1 ,3 -butadiene
Acrylonitrile
Chloroprene
Xylenes
0.45
0.077
0.13
0.17
0.029
0.03
0.4
0.011
0.011
0.038
0.011
0.000083
7.7
0.00057
0.091
0.045
0.015
0.0021
10
Total
62
62
61
61
60
57
36
17
16
11
7
6
o
J
2
2
2
1
1
1
468
62
62
61
61
60
57
61
60
60
11
60
60
61
58
16
2
1
1
61
875
100.00
100.00
100.00
100.00
100.00
100.00
59.02
28.33
26.67
100.00
11.67
10.00
4.92
3.45
12.50
100.00
100.00
100.00
1.64
53.49
13.25
13.25
13.03
13.03
12.82
12.18
7.69
3.63
3.42
2.35
1.50
1.28
0.64
0.43
0.43
0.43
0.21
0.21
0.21
13.25
26.50
39.53
52.56
65.38
77.56
85.26
88.89
92.31
94.66
96.15
97.44
98.08
98.50
98.93
99.36
99.57
99.79
100.00
River Rouge, Michigan - RRMI
Acet aldehyde
Formaldehyde
0.45
0.077
Total
55
55
110
57
57
114
96.49
96.49
96.49
50.00
50.00
50.00
100.00
Detroit, Michigan - SWMI
Acet aldehyde
Formaldehyde
Propionaldehyde
0.45
0.077
0.8
Total
28
28
1
57
28
28
28
84
100.00
100.00
3.57
67.86
49.12
49.12
1.75
49.12
98.25
100.00
15-20
-------
Observations from Table 15-4 for DEMI include the following:
Nineteen pollutants, of which eight are NATTS MQO Core Analytes, failed at least
one screen for DEMI.
Eleven pollutants contributed to 95 percent of the total failed screens for DEMI; of
these, six are NATTS MQO Core Analytes. Hexavalent chromium and
benzo(a)pyrene were added to the pollutants of interest for DEMI because they are
NATTS MQO Core Analytes, even though they did not contribute to 95 percent of
the total failed screens. Four additional pollutants (chloroform, tetrachloroethylene,
trichloroethylene, and vinyl chloride) were also added to the list, even though they
did not fail any screens, because they too are NATTS MQO Core Analytes. These
four pollutants are not shown in Table 15-4 but are shown in subsequent tables in the
sections that follow.
Of the pollutants failing screens, approximately 53 percent of the measured detections
failed screens. Ten pollutants failed 100 percent of their screens, although their
detection rates varied.
The six pollutants failing the most screens contributed to over 75 percent of the total
failed screens, are all NATTS MQO Core Analytes, and failed 100 percent of their
screens.
Observations from Table 15-4 for RRMI and SWMI include the following:
Acetaldehyde and formaldehyde failed screens for RRMI. These pollutants
contributed equally to the total failed screens.
Acetaldehyde and formaldehyde failed the majority of screens for SWMI, each
contributing to 49 percent of the total failed screens. Propionaldehyde failed a single
screen for SWMI. These three pollutants are the only carbonyl compounds with risk
screening values.
15.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Michigan monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Michigan monitoring sites, where the data meet the
applicable criteria. Concentration averages for select pollutants are also presented graphically for
the sites to illustrate how the sites' concentrations compare to the program-level averages, as
presented in Section 4.1. In addition, concentration averages for select pollutants are presented
from previous years of sampling in order to characterize concentration trends at the sites.
Additional site-specific statistical summaries for DEMI, RRMI, and SWMI are provided in
Appendices J, L, M, and O.
15-21
-------
15.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for the Michigan sites, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Michigan
monitoring sites are presented in Table 15-5, where applicable. Note that concentrations of the
PAHs and hexavalent chromium are presented in ng/m3 for ease of viewing. Also note that if a
pollutant was not detected in a given calendar quarter, the quarterly average simply reflects "0"
because only zeros substituted for non-detects were factored into the quarterly average
concentration.
Table 15-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Michigan Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(jig/m3)
Dearborn, Michi
Acetaldehyde
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
62/62
61/61
57/61
61/61
61/61
11/61
61/61
62/62
1.67
ฑ0.16
0.84
ฑ0.10
0.10
ฑ0.01
0.59
ฑ0.05
0.52
ฑ0.10
0
0.42
ฑ0.13
2.01
ฑ0.23
2nd
Quarter
Average
(jig/m3)
3rd
Quarter
Average
(jig/m3)
4th
Quarter
Average
(jig/m3)
Annual
Average
(jig/m3)
gan - DEMI
1.80
ฑ0.29
0.88
ฑ0.26
0.08
ฑ0.03
0.63
ฑ0.05
1.58
ฑ0.24
0.03
ฑ0.03
0.45
ฑ0.13
2.04
ฑ0.76
1.77
ฑ0.30
0.90
ฑ0.18
0.09
ฑ0.03
0.70
ฑ0.04
0.68
ฑ0.19
0
0.91
ฑ0.40
4.14
ฑ0.90
1.63
ฑ0.37
0.84
ฑ0.17
0.10
ฑ0.03
0.69
ฑ0.04
0.52
ฑ0.16
0.03
ฑ0.02
0.64
ฑ0.24
2.17
ฑ0.49
1.72
ฑ0.14
0.86
ฑ0.09
0.09
ฑ0.01
0.65
ฑ0.02
0.82
ฑ0.14
0.01
ฑ0.01
0.61
ฑ0.13
2.60
ฑ0.39
a Average concentrations provided for the pollutants below the blue line are presented in ng/m for
ease of viewing.
15-22
-------
Table 15-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Michigan Monitoring Sites (Continued)
Pollutant
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Acenaphthene3
Benzo(a)pyrenea
Fluoranthene3
Fluorene3
Hexavalent Chromium3
Naphthalene3
#of
Measured
Detections
vs. # of
Samples
56/61
5/61
8/61
60/60
58/60
60/60
60/60
60/61
60/60
1st
Quarter
Average
(Ug/m3)
0.18
ฑ0.05
0.01
ฑ0.01
0.01
ฑ0.01
3.67
ฑ1.69
0.15
ฑ0.07
2.05
ฑ0.50
3.66
ฑ0.91
0.04
ฑ0.02
98.14
ฑ 13.86
2nd
Quarter
Average
(Ug/m3)
0.15
ฑ0.06
0
0
15.04
ฑ11.35
0.26
ฑ0.26
6.52
ฑ5.02
12.46
ฑ9.32
0.05
ฑ0.02
136.83
ฑ43.19
3rd
Quarter
Average
(Ug/m3)
0.20
ฑ0.06
0.02
ฑ0.02
0.01
ฑ0.01
27.99
ฑ 14.22
0.13
ฑ0.06
10.26
ฑ3.87
22.15
ฑ9.80
0.05
ฑ0.02
217.74
ฑ 59.44
4th
Quarter
Average
(Ug/m3)
0.18
ฑ0.06
0
0.01
ฑ0.01
5.49
ฑ2.48
0.21
ฑ0.15
2.44
ฑ0.99
5.36
ฑ2.17
0.05
ฑ0.01
113.75
ฑ 32.02
Annual
Average
(Ug/m3)
0.18
ฑ0.03
0.01
ฑ0.01
0.01
ฑ0.01
13.42
ฑ5.17
0.19
ฑ0.07
5.45
ฑ1.78
11.19
ฑ3.84
0.05
ฑ0.01
143.35
ฑ23.07
River Rouge, Michigan - RRMI
Acetaldehyde
Formaldehyde
57/57
57/57
1.52
ฑ0.45
1.90
ฑ0.60
1.87
ฑ0.32
3.09
ฑ1.04
1.87
ฑ0.29
4.86
ฑ0.88
1.43
ฑ0.30
2.79
ฑ0.50
1.68
ฑ0.17
3.23
ฑ0.47
Detroit, Michigan - SWMI
Acetaldehyde
Formaldehyde
28/28
28/28
1.32
ฑ0.23
2.50
ฑ0.31
1.43
ฑ0.60
2.93
ฑ2.05
2.61
ฑ1.55
4.11
ฑ1.11
1.56
ฑ0.42
2.11
ฑ0.43
1.74
ฑ0.43
2.90
ฑ0.60
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for
ease of viewing.
Observations for DEMI from Table 15-5 include the following:
The pollutants with the highest annual average concentrations by mass are
formaldehyde and acetaldehyde; all other annual average concentrations are less than
1.0|ig/m3.
The third quarter average concentration of formaldehyde is twice the other quarterly
averages. A review of the data shows that the maximum concentration of
formaldehyde was measured on July 20, 2011 (6.99 |ig/m3) although similar
concentrations were also measured in June and August. Of the nine concentrations
greater than 4 |ig/m3, eight were measured during the third quarter of 2011.
15-23
-------
The second quarter average concentration of chloroform is three times higher than the
other quarterly averages. A review of the data shows that the maximum concentration
of chloroform was measured on June 20, 2011 (2.25 |ig/m3) although similar
concentrations were also measured in May and June. Of the 16 chloroform
concentrations greater than 1 |ig/m3, 13 were measured during the second quarter of
2011.
The third quarter average concentration of ethylbenzene is higher than the other
quarter averages and has a relatively high confidence interval associated with it. A
review of the data shows that the highest concentration of this pollutant was measured
on August 7, 2011 (3.34 |ig/m3) and is nearly twice the next highest concentration
(1.91 |ig/m3 measured on August 13, 2011). This concentration is also the sixth
highest ethylbenzene concentration measured among NMP sites sampling this
pollutant. Of the nine ethylbenzene concentrations greater than 1 |ig/m3 measured at
DEMI, more than half were measured during the third quarter of 2011.
Similar observations for chloroform and ethylbenzene were made in the 2010 NMP
report.
The second and third quarter averages of acenaphthene, fluoranthene, and fluorene
are significantly higher than the other quarterly averages and have relatively high
confidence intervals associated with them. The highest concentrations of these
pollutants were all measured on the same days, June 8, 2011 and July 2, 2011. The
highest concentrations of these compounds were measured in June, July, and August,
generally on the same days, although the order varied.
A similar trend is shown for naphthalene. The maximum concentration of
naphthalene was also measured on July 2, 2011. This was the fourth highest
concentration of naphthalene measured across the program. Of the 12 highest
concentrations of naphthalene measured at DEMI (those greater than 200 ng/m3), nine
were measured during the third quarter of 2011 (plus two in June and one in October).
The second quarter average concentration of benzo(a)pyrene is the same as its
associated confidence interval, an indicator of considerable variability in the
concentrations measured. The maximum benzo(a)pyrene concentration (1.99 ng/m3)
was measured on May 3, 2011 and is also the maximum concentration measured
among NMP sites sampling PAHs. The next highest concentration measured during
the second quarter of 2011 at DEMI was considerably less (0.236 ng/m3) and the
median concentration for the second quarter is 0.149 ng/m3. The fourth quarter
average concentration and its associated confidence interval also reflect a relatively
high level of variability in the measurements. The only other measurement greater
than 1 ng/m3 at DEMI was measured on October 6, 2011. The next highest
concentration measured during the fourth quarter was 0.269 ng/m3 and the median
concentration for the fourth quarter is 0.142 ng/m3.
15-24
-------
Observations for RRMI and SWMI from Table 15-5 include the following:
The annual average concentration of acetaldehyde for RRMI is similar to the annual
average concentration for SWMI. Both are similar to the annual average acetaldehyde
concentration for DEMI. The annual formaldehyde averages for the sites vary a little
more.
The third quarter average concentration of acetaldehyde for SWMI is greater than the
other quarterly averages and has a relatively large confidence interval associated with
it. A review of the data shows that the maximum concentration (6.70 |ig/m3) was
measured on August 7, 2011 and is more than twice the next highest concentration
(2.85 |ig/m3, measured on August 19, 2011).
The second and third quarter average concentrations of formaldehyde for RRMI and
SWMI are higher than the other quarterly averages for 2011 and have relatively large
confidence intervals associated with them. The maximum formaldehyde
concentration was measured at RRMI on July 20, 2011 (8.25 |ig/m3), which is the
same day the maximum concentration of formaldehyde was measured at DEMI.
Because SWMI sampled on a l-in-12 day sampling schedule, no sample was
collected at this site on July 20, 2011. However, the maximum formaldehyde
concentration for SWMI (8.36 |ig/m3) was measured on the same day that the second
highest concentration was measured at RRMI, June 8, 2011. The highest
concentrations of formaldehyde at both sites were measured between June and
September.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the
Michigan sites from those tables include the following:
DEMI appears in Tables 4-9 through 4-12 a total of 10 times.
DEMI has the second highest annual average concentration of chloroform, behind
only NBIL, as shown in Table 4-9. However, the difference between the annual
chloroform average for DEMI and NBIL is significant.
The annual average concentration of acenaphthene for DEMI is the highest among
NMP sites sampling PAHs. DEMI's annual average concentrations of fluorene and
naphthalene each rank second and the annual average concentration of
benzo(a)pyrene ranks third among sites sampling PAHs.
The annual average concentration of hexavalent chromium for DEMI ranks fourth
highest among sites sampling this pollutant.
The rankings for DEMI are similar to those for the 2010 NMP report.
15-25
-------
None of the Michigan sites appear among the sites with the highest annual average
concentrations of acetaldehyde. RRMI ranks tenth for its annual average
concentration of formaldehyde.
15.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde and
formaldehyde were created for all three Michigan sites. In addition, box plots for benzene,
benzo(a)pyrene, 1,3-butadiene, hexavalent chromium, and naphthalene were created for DEMI.
Figures 15-13 through 15-19 overlay the sites' minimum, annual average, and maximum
concentrations onto the program-level minimum, first quartile, median, average, third quartile,
and maximum concentrations, as described in Section 3.5.3.
Figure 15-13. Program vs. Site-Specific Average Acetaldehyde Concentrations
DEI'.'I
H-
S'.'.'f.'l
ID
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
15-26
-------
Figure 15-14. Program vs. Site-Specific Average Benzene Concentration
DEf.'l
) 1 2 3
Program: IstQuartile
Site: Site Average
o
Program Max Concentration = 23. 8 ug/m3
4567891
Concentration (pg/mi)
2ndQuartile SrdQuartile 4thQuartile Average
n n
Site Minimum/Maximum
Figure 15-15. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
-o-
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 15-16. Program vs. Site-Specific Average 1,3-Butadiene Concentration
I Program Max Concentration = 9.51 ng/
3.5
15
Concentration
2.5
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
15-27
-------
Figure 15-17. Program vs. Site-Specific Average Formaldehyde Concentrations
S'.'.'f.'l
13
IS
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
Figure 15-18. Program vs. Site-Specific Average Hexavalent Chromium Concentration
DEf.'l
1
3.35
0.1
3.15
Concentration (
3.2
3.25
3.3
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 15-19. Program vs. Site-Specific Average Naphthalene Concentration
DEf.'l
i Program Max Concentration = 779 ng/ms
100
153
200 250 300
Concentration (ng/m3)
35C
433
453
533
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile SrdQuartile 4thQuartile Ave
n
Site Minimum/Maximum
'rage
15-28
-------
Observations from Figures 15-13 through 15-19 include the following:
Figure 15-13 includes the box plots for acetaldehyde for all three sites. The box
plots show that not only are all three sites' annual averages less than the program-
level average concentration of acetaldehyde, they are all relatively similar to each
other (less than 0.1 |ig/m3 separates them). However, the range of concentrations
measured at SWMI is twice as wide as the range measured at DEMI and RRMI.
Although no non-detects of acetaldehyde were measured at the Michigan sites or
across the program, the two minimum concentrations of acetaldehyde were
measured at RRMI.
Figure 15-14 is the box plot for benzene. Note that the program-level maximum
concentration (23.8 |ig/m3) is not shown directly on the box plot because the scale
of the box plot would be too large to readily observe data points at the lower end
of the concentration range. Thus, the scale has been reduced to 10 |ig/m3.
Figure 15-14 shows that DEMI's annual average benzene concentration is just
less than the program-level average concentration. The maximum concentration
of benzene measured at DEMI is considerably less than the maximum
concentration measured at the program level. There were no non-detects of
benzene measured at DEMI or across the program.
Figure 15-15 is the box plot for benzo(a)pyrene for DEMI. Note that the program-
level first quartile for this pollutant is zero and is not visible on this box plot. The
box plot shows that the maximum concentration of benzo(a)pyrene was measured
at DEMI. The annual average concentration for DEMI is greater than both the
program-level average and third quartile. Recall that the annual average
benzo(a)pyrene concentration for DEMI is the third highest annual average
concentration of this pollutant among sites sampling PAHs. Two non-detects of
benzo(a)pyrene were measured at DEMI.
Figure 15-16 is the box plot for 1,3-butadiene. Similar to the benzene box plot,
the program-level maximum concentration (9.51 |ig/m3) is not shown directly on
the box plot as the scale has been reduced to 3 |ig/m3 to allow for the observation
of data points at the lower end of the concentration range. Figure 15-16 shows
that the annual average concentration for DEMI is similar to the program-level
average concentration. The maximum 1,3-butadiene concentration measured at
DEMI is considerably less than the maximum concentration measured across the
program. Four non-detects of 1,3-butadiene were measured at DEMI.
Figure 15-17 includes the box plots for formaldehyde for all three sites. The box
plots show that the annual averages for these three sites vary by less than
0.70 |ig/m3. The annual average for DEMI is just less than the program-level
average, the annual average for SWMI is similar to the program-level average,
and the annual average for RRMI is just greater than the program-level average.
All three annual averages are between the program-level median and third quartile
(or between 50th and 75th percentile).The range of concentrations measured is
similar for RRMI and SWMI and slightly smaller for DEMI. The maximum
concentration measured at each site is less than the maximum concentration
measured at the program level. Although no non-detects of formaldehyde were
15-29
-------
measured at the Michigan sites or across the program, the two minimum
concentrations of formaldehyde were measured at RRMI.
Figure 15-18 is the box plot for hexavalent chromium. The box plot shows that
annual average concentration for DEMI is nearly twice the program-level average
concentration. The maximum concentration measured at DEMI is not the
maximum concentration measured across the program, but it was the second
highest. There was a single non-detect of this pollutant measured at DEMI.
Figure 15-19 is the box plot for naphthalene. Similar to the benzene and
1,3-butadiene box plots, the program-level maximum concentration (779 ng/m3)
is not shown directly on the box plot as the scale has been reduced to 500 ng/m3 to
allow for the observation of data points at the lower end of the concentration
range. Figure 15-19 shows that the annual average concentration of naphthalene
for DEMI is nearly twice the program-level average concentration. Recall from
the previous section that DEMI's annual average concentration is the second
highest annual average among NMP sites sampling this pollutant. The maximum
naphthalene concentration measured at DEMI is less than the maximum
concentration measured across program, although it was the fourth highest
naphthalene concentration measured across the program. The minimum
naphthalene concentration measured at DEMI is greater than the program-level
first quartile (25th percentile).
15.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. DEMI has sampled VOCs and carbonyl compounds under the NMP since 2003
and hexavalent chromium since 2005. Thus, Figures 15-20 through 15-24 present the annual
statistical metrics for acetaldehyde, benzene, 1,3-butadiene, formaldehyde, and hexavalent
chromium for DEMI. The statistical metrics presented for assessing trends include the
substitution of zeros for non-detects.
Sampling for PAHs at DEMI did not begin until 2008, therefore a trends analysis was not
conducted for the pollutants for these methods. Although RRMI and SWMI have sampled under
the NMP previously, they have not sampled continuously for 5 consecutive years; thus, a trends
analysis was not performed for these sites.
15-30
-------
Figure 15-20. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at DEMI
ST
.a ^
c
1
3 4
|
< 3 _
-L
*
<
^
i
r
>-
'
l-l-,
1 '*~~l 1 *~~l
"*~ """- -fc i* "*
Y Y u, -r T
2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Pe re entile Minimum Median Maximum * 95th Percentile ..^.. Average
Figure 15-21. Annual Statistical Metrics for Benzene Concentrations
Measured at DEMI
2005 2006
2007 2008
Year
* 5th Percentile - Minimum Median - Maximum 95th Percentile * Average
15-31
-------
Figure 15-22. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at DEMI
tration (\ifjn\3)
S i
A i/e rage Concert
j e
0 -
+ -
^^m
2004
[
2005
* 5th Percentile
T
^.-, T E
r^ r^n
"* *. .
r f ? ' t
2006 2007 2003 2009 2010 2011
Year
M nimum Median Maximum 95th Percentile . .^.. Average
Figure 15-23. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at DEMI
1
Concentration
I
5 -
F
2003
*
I
1
-L.
T
2004
5th Percentile
ป..
JL T f r^i
~^~
--...I rn LJ
V ^^ ^^ U.J
2005 2006 2007 2008 2009 2010 2011
Year
Minimum Median Maximum 95th Percentile "^"Average
15-32
-------
Figure 15-24. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at DEMI
c
a
E
= '
I
3
E
2008
Year
5th Percentile Minimum Median Maximum
95th Percentile
. Average
Observations from Figure 15-20 for acetaldehyde measurements at DEMI include the
following:
Carbonyl compounds have been sampled continuously at DEMI under the NMP since
2003. The site began sampling on a l-in-12 day schedule in 2003 then changed to a
l-in-6 day schedule in the spring of 2004.
Carbonyl compound samples from the primary sampler were invalidated from
March 13, 2007 through March 25, 2008 by the state of Michigan due to a leak in the
sample line. With only 12 valid samples in 2007 and less than 85 percent in 2008, no
statistical metrics are presented for 2007 or 2008.
The maximum acetaldehyde concentration shown was measured in 2004
(7.84 |ig/m3). Of the six concentrations greater than 5 |ig/m3 measured at DEMI, three
were measured in 2004, two were measured in 2005, and one was measured in 2006.
The average concentration exhibits a decreasing trend after 2004 and an increasing
trend after 2009.
Even with the maximum concentration at a minimum for 2011, the median, average,
and 95th percentile all exhibit slight increases from 2010 levels.
There have been no non-detects of acetaldehyde measured at DEMI.
15-33
-------
Observations from Figure 15-21 for benzene measurements at DEMI include the
following:
VOCs have been sampled continuously at DEMI under the NMP since 2003.
However, the l-in-12 day schedule in 2003 combined with a number of invalids
resulted in a low completeness; as a result, no statistical metrics are presented for
2003 and Figure 15-21 begins with 2004.
The three highest benzene concentrations were all measured in 2004 and ranged from
5.44 |ig/m3to 7.62 |ig/m3. Only one other conc<
measured at DEMI and was measured in 2007.
5.44 |ig/m3 to 7.62 |ig/m3. Only one other concentration greater than 5 |ig/m3 has been
Both the median and average concentrations exhibit a steady decreasing trend over
the period shown, reaching a minimum in 2009. Although a slight increase is shown
for 2010 followed by a slight decrease in 2011, the changes in the later years are not
statistically significant.
The difference between the median and average concentrations has also decreased,
indicating less variability in the measurements. For the last three years of sampling,
less than 0.1 |ig/m3 separates these two statistical parameters.
The minimum concentration is greater than zero for all years shown, indicating that
this pollutant has been detected in every VOC sample collected at DEMI.
Observations from Figure 15-22 for 1,3-butadiene measurements at DEMI include the
following:
Recall that even though VOC sampling at DEMI began in 2003, Figure 15-22 begins
with data from 2004 due to low completeness in 2003.
The maximum 1,3-butadiene concentration was measured on October 18, 2004. This
is the only 1,3-butadiene measurement greater than 1 |ig/m3, although concentrations
greater than 0.90 |ig/m3 were measured in 2004 and 2006.
For 2004, the minimum, 5th percentile, and median concentrations are all zero,
indicating that at least 50 percent of the measurements were non-detects. Yet at the
same time, 2004 also has the two highest concentrations measured at the site and the
maximum 95th percentile. This indicates there is a high level of variability in the
measurements. Although there were fewer non-detects in 2006, as indicated by the
increase in the median concentration, this year also reflects a high level of variability
compared to other years.
After 2006, the average 1,3-butadiene concentration decreased, reaching a minimum
in 2009. Nearly all of the statistical parameters are at a minimum for 2009.
15-34
-------
The number of non-detects measured for 1,3-butadiene decreased significantly after
the first few years of sampling. The number of non-detects decreased from 29 in
2004, to 19 in 2005, to five in 2006. Only one to two non-detects were measured in
the following years until 2011, when four non-detects were measured.
Observations from Figure 15-23 for formaldehyde measurements at DEMI include the
following:
Recall that carbonyl compounds have been sampled continuously at DEMI under the
NMP since 2003 but due to a leak in the sample line, samples collected between
March 13, 2007 through March 25, 2008 were invalidated and thus, no statistical
metrics are presented for 2007 or 2008.
The maximum formaldehyde concentration shown was measured in 2005
(33.1 |ig/m3). The next four highest concentrations measured at DEMI were also
measured in 2005 and range from 13.3 |ig/m3 to 20.9 |ig/m3. The only other
formaldehyde concentrations greater than 10 |ig/m3 were measured in 2004.
The decrease in the average concentration shown between 2005 and 2006 is
significant (from 5.35 |ig/m3to 2.92 |ig/m3). The average concentration for tt
following did not vary significantly from the average concentration for 2006.
Even though the difference between the 5th and 95th percentiles (the range into which
the majority of the measurements fall) increased from 2010 to 2011, slight decreases
are shown for the median and average concentrations.
There have been no non-detects of formaldehyde measured at DEMI.
Observations from Figure 15-24 for hexavalent chromium measurements at DEMI
include the following:
The maximum hexavalent chromium concentration was measured in 2006. The two
highest hexavalent chromium concentrations for this site were measured on
July 4, 2006 (0.496 ng/m3) and on July 5, 2008 (0.392 ng/m3). A similar
concentration was also measured on January 1, 2009 (0.372 ng/m3).
Although a decrease in the average concentration is shown from 2006 (0.068 ng/m3)
to 2007 (0.042 ng/m3), the confidence intervals calculated are relatively large as a
result of the highest concentrations and indicate that these changes are not statistically
significant. However, the average concentration changed little after 2006, ranging
from 0.036 ng/m3 in 2009 to 0.047 ng/m3 in 2011.
The minimum concentrations and 5th percentiles for several years are zero, indicating
the presence of non-detects.
15-35
-------
15.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
Michigan monitoring sites. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
15.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Michigan monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
15.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Michigan sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 15-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
15-36
-------
Table 15-6. Risk Approximations for the Michigan Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Dearborn, Michigan - DEMI
Acenaphthene3
Acetaldehyde
Benzene
Benzo(a)pyrenea
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
Fluoranthene3
Fluorene3
Formaldehyde
Hexavalent Chromium3
Naphthalene3
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.000088
0.0000022
0.0000078
0.00176
0.00003
0.000006
0.000026
0.0000025
0.000088
0.000088
0.000013
0.012
0.000034
0.00000026
0.0000048
0.0000088
0.009
0.03
0.002
0.1
0.098
2.4
1
0.0098
0.0001
0.003
0.04
0.002
0.1
60/60
62/62
61/61
58/60
57/61
61/61
61/61
11/61
61/61
60/60
60/60
62/62
60/61
60/60
56/61
5/61
8/61
0.01
ฑ0.01
1.72
ฑ0.14
0.86
ฑ0.09
<0.01
ฑ<0.01
0.09
ฑ0.01
0.65
ฑ0.02
0.82
ฑ0.14
0.01
ฑ0.01
0.61
ฑ0.13
0.01
ฑ<0.01
0.01
ฑ0.01
2.60
ฑ0.39
0.01
ฑ0.01
0.14
ฑ0.02
0.18
ฑ0.03
0.01
ฑ0.01
0.01
ฑ0.01
1.18
3.78
6.73
0.33
2.79
3.92
0.39
1.52
0.48
0.98
33.85
0.56
4.87
0.05
0.03
0.02
0.19
0.03
0.05
0.01
0.01
O.01
0.01
0.27
0.01
0.05
0.01
O.01
0.01
River Rouge, Michigan - RRMI
Acetaldehyde
Formaldehyde
0.0000022
0.000013
0.009
0.0098
57/57
57/57
1.68
ฑ0.17
3.23
ฑ0.47
3.69
41.97
0.19
0.33
Detroit, Michigan - SWMI
Acetaldehyde
Formaldehyde
0.0000022
0.000013
0.009
0.0098
28/28
28/28
1.74
ฑ0.43
2.90
ฑ0.60
3.82
37.70
0.19
0.30
= a Cancer URE or Noncancer RfC is not available.
3 For the annual average concentration of this pollutant in ng/m3, refer to Table 15-5.
15-37
-------
Observations from Table 15-6 include the following:
Formaldehyde has the highest annual average concentration for each of the Michigan
monitoring sites. This pollutant also has the highest cancer risk approximation for
each site, ranging from 33.85 in-a-million for DEMI to 41.97 in-a-million for RRMI.
The range of cancer risk approximations for acetaldehyde was even tighter, ranging
from 3.69 in-a-million for RRMI to 3.82 in-a-million for SWMI.
Aside from formaldehyde, the pollutants with the highest cancer risk approximations
for DEMI were benzene, naphthalene, and carbon tetrachloride.
None of the pollutants of interest for the Michigan monitoring sites have noncancer
hazard approximations greater than 1.0, indicating that no adverse health effects are
expected from these individual pollutants. The pollutant with the highest noncancer
hazard approximation for each site is formaldehyde.
15.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 15-7 and 15-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 15-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 15-6. Table 15-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 15-6.
The pollutants listed in Table 15-7 and 15-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 15.3, all three Michigan sites sampled carbonyl compounds; DEMI also sampled for
VOCs, PAHs, and hexavalent chromium. In addition, the cancer risk and noncancer hazard
approximations are limited to those pollutants with enough data to meet the criteria for annual
averages to be calculated. A more in-depth discussion of this analysis is provided in
Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this analysis
may help policy-makers prioritize their air monitoring activities.
15-38
-------
Table 15-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Michigan Monitoring Sites
VO
Top 10 Total Emissions for Pollutants
with Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Dearborn, Michigan (Wayne County) - DEMI
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
Tetrachloroethylene
Coke Oven Emissions, PM
Trichloroethylene
1,134.11
612.43
500.03
334.62
134.38
74.43
52.69
47.69
35.72
13.67
Coke Oven Emissions, PM
Benzene
Formaldehyde
POM, Group 5a
Hexavalent Chromium, PM
1,3 -Butadiene
Arsenic, PM
Naphthalene
Nickel, PM
Ethylbenzene
3.54E-02
8.85E-03
7.96E-03
7.57E-03
6.69E-03
4.03E-03
3.81E-03
2.53E-03
1.42E-03
1.25E-03
Formaldehyde
Benzene
Naphthalene
Carbon Tetrachloride
Acetaldehyde
1,3 -Butadiene
Ethylbenzene
Acenaphthene
Fluorene
Hexavalent Chromium
33.85
6.73
4.87
3.92
3.78
2.79
1.52
1.18
0.98
0.56
River Rouge, Michigan (Wayne County) - RRMI
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
Tetrachloroethylene
Coke Oven Emissions, PM
Trichloroethylene
1,134.11
612.43
500.03
334.62
134.38
74.43
52.69
47.69
35.72
13.67
Coke Oven Emissions, PM
Benzene
Formaldehyde
POM, Group 5a
Hexavalent Chromium, PM
1,3 -Butadiene
Arsenic, PM
Naphthalene
Nickel, PM
Ethylbenzene
3.54E-02
8.85E-03
7.96E-03
7.57E-03
6.69E-03
4.03E-03
3.81E-03
2.53E-03
1.42E-03
1.25E-03
Formaldehyde
Acetaldehyde
41.97
3.69
-------
Table 15-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Michigan Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants
with Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Cancer Risk
Approximation
Pollutant (in-a-million)
Detroit, Michigan (Wayne County) - SWMI
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
Tetrachloroethylene
Coke Oven Emissions, PM
Trichloroethylene
1,134.11
612.43
500.03
334.62
134.38
74.43
52.69
47.69
35.72
13.67
Coke Oven Emissions, PM
Benzene
Formaldehyde
POM, Group 5a
Hexavalent Chromium, PM
1,3 -Butadiene
Arsenic, PM
Naphthalene
Nickel, PM
Ethylbenzene
3.54E-02
8.85E-03
7.96E-03
7.57E-03
6.69E-03
4.03E-03
3.81E-03
2.53E-03
1.42E-03
1.25E-03
Formaldehyde 37.70
Acetaldehyde 3.82
-------
Table 15-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Michigan Monitoring Sites
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Dearborn, Michigan (Wayne County) - DEMI
Hydrochloric acid
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Methyl isobutyl ketone
3,765.69
2,480.93
1,912.74
1,227.86
1,134.11
612.43
551.94
500.03
334.62
277.33
Acrolein
Hydrochloric acid
Manganese, PM
1,3 -Butadiene
Cyanide Compounds, gas
Formaldehyde
Arsenic, PM
Benzene
Acetaldehyde
Nickel, PM
1,866,893.10
188,284.52
98,186.30
67,191.86
64,535.63
62,493.26
58,998.69
37,803.81
37,180.09
32,767.48
Formaldehyde
Acetaldehyde
Naphthalene
1,3 -Butadiene
Benzene
Chloroform
Carbon Tetrachloride
Tetrachloroethylene
Trichloroethylene
Ethylbenzene
0.27
0.19
0.05
0.05
0.03
0.01
0.01
<0.01
<0.01
<0.01
River Rouge, Michigan (Wayne County) - RRMI
Hydrochloric acid
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Methyl isobutyl ketone
3,765.69
2,480.93
1,912.74
1,227.86
1,134.11
612.43
551.94
500.03
334.62
277.33
Acrolein
Hydrochloric acid
Manganese, PM
1,3 -Butadiene
Cyanide Compounds, gas
Formaldehyde
Arsenic, PM
Benzene
Acetaldehyde
Nickel, PM
1,866,893.10
188,284.52
98,186.30
67,191.86
64,535.63
62,493.26
58,998.69
37,803.81
37,180.09
32,767.48
Formaldehyde
Acetaldehyde
0.33
0.19
-------
Table 15-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Michigan Monitoring Sites (Continued)
to
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Detroit, Michigan (Wayne County) - SWMI
Hydrochloric acid
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Methyl isobutyl ketone
3,765.69
2,480.93
1,912.74
1,227.86
1,134.11
612.43
551.94
500.03
334.62
277.33
Acrolein
Hydrochloric acid
Manganese, PM
1,3 -Butadiene
Cyanide Compounds, gas
Formaldehyde
Arsenic, PM
Benzene
Acetaldehyde
Nickel, PM
1,866,893.10
188,284.52
98,186.30
67,191.86
64,535.63
62,493.26
58,998.69
37,803.81
37,180.09
32,767.48
Formaldehyde 0.30
Acetaldehyde 0.19
-------
Observations from Table 15-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Wayne County.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
cancer UREs) for Wayne County are coke oven emissions, benzene, and
formaldehyde.
Six of the highest emitted pollutants in Wayne County also have the highest toxicity-
weighted emissions.
Formaldehyde has the highest cancer risk approximations for all three Michigan sites.
This pollutant appears on both emissions-based lists. Acetaldehyde, the other
pollutant of interest in common for all three Michigan sites, is one of the highest
emitted pollutants but does not appear among those with the highest toxicity-
weighted emissions.
In addition to formaldehyde, benzene, naphthalene, ethylbenzene, and 1,3-butadiene
are among the pollutants with the highest cancer risk approximations for DEMI and
appear on both emissions-based lists. Hexavalent chromium has the fifth highest
toxicity-weighted emissions but does not appear among the highest emitted. Carbon
tetrachloride does not appear on either emissions-based list.
POM, Group 5a ranks fourth for toxicity-weighted emissions in Wayne County.
POM, Group 5a includes benzo(a)pyrene, which has one of the lowest cancer risk
approximations of the pollutants of interest for DEMI.
Observations from Table 15-8 include the following:
Hydrochloric acid, toluene, and xylenes are the highest emitted pollutants with
noncancer RfCs in Wayne County. Wayne County has the highest hydrochloric acid
emissions of any county with an NMP site (by an order of magnitude).
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) for Wayne County are acrolein, hydrochloric acid, and manganese.
Although acrolein was sampled for at DEMI, this pollutant was excluded from the
pollutants of interest designation and thus subsequent risk-based screening
evaluations due to questions about the consistency and reliability of the
measurements, as discussed in Section 3.2.
Four of the highest emitted pollutants in Wayne County also have the highest
toxicity-weighted emissions.
The pollutant with the highest noncancer hazard approximation for all three Michigan
sites is formaldehyde, although none of the pollutants of interest have associated
noncancer hazard approximations greater than 1.0. Formaldehyde emissions rank
sixth for Wayne County and sixth for toxicity-weighted emissions.
15-43
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Acetaldehyde is the other pollutant these sites have in common; this pollutant also
appears on both emissions-based lists. Acetaldehyde ranks ninth for both quantity
emitted and toxicity-weighted emissions.
Benzene is the only other pollutant that appears on all three lists for DEMI.
15.6 Summary of the 2011 Monitoring Data for DEMI, RRMI, and SWMI
Results from several of the data treatments described in this section include the
following:
ปซป Nineteen pollutants, of which eight are NA TTS MQO Core Analytes, failed screens
for DEMI. Acetaldehyde and formaldehyde both failed screens for RRMI and SWMI
and propionaldehyde also failed a single screen for SWMI.
*ป* Of the site-specific pollutants of interest, formaldehyde had the highest annual
average concentration for all three sites.
ปซป DEMI has the second highest annual average concentration of chloroform among
NMP sites sampling VOCs. DEMI also has the highest annual average concentration
of acenaphthene and the second the highest annual average concentrations of
fluorene and naphthalene among NMP sites sampling PAHs.
ปซป Concentrations of benzene have been steadily decreasing at DEMI since sampling
began at this site.
15-44
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16.0 Site in Missouri
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Missouri, and integrates these concentrations with
emissions, meteorological, and risk information. Data generated by sources other than ERG are
not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
16.1 Site Characterization
This section characterizes the S4MO monitoring site by providing geographical and
physical information about the location of the site and the surrounding area. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
site and assist in the interpretation of the ambient monitoring measurements.
The S4MO monitoring site is located in the St. Louis, MO-IL MSA. Figure 16-1 is a
composite satellite image retrieved from ArcGIS Explorer showing the monitoring site in its
urban location. Figure 16-2 identifies nearby point source emissions locations by source
category, as reported in the 2008 NEI for point sources. Note that only sources within 10 miles
of the site are included in the facility counts provided in Figure 16-2. A 10-mile boundary was
chosen to give the reader an indication of which emissions sources and emissions source
categories could potentially have a direct effect on the air quality at the monitoring site. Further,
this boundary provides both the proximity of emissions sources to the monitoring site as well as
the quantity of such sources within a given distance of the site. Sources outside the 10-mile
radius are still visible on the map, but have been grayed out in order to show emissions sources
just outside the boundary. Table 16-1 provides supplemental geographical information such as
land use, location setting, and locational coordinates.
16-1
-------
Figure 16-1. St. Louis, Missouri (S4MO) Monitoring Site
to
-------
Figure 16-2. NEI Point Sources Located Within 10 Miles of S4MO
arm'trw so 5'trw
Note: Due la facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
S4MO NATTS site
Source Category Group (No. of Facilities)
i= Air-con diiioning/Ref figuration (1)
-fi Aircraft Operations (21)
I Aspnatt Processing/Roofing Manufacturing (1)
H Automobile/Truck Manufacturing (1)
$} Bakery (1)
y BreweryDistilleryMAnery (1)
ft Buiktiny Construction i'2)
B Bulk Termmaf&'Bulk Plants (6)
C Chem.cal Manufacturing (9)
Concrete Batcti Plant (11)
E> ] Crematory -Animal/Human (1)
fฃ) Dry Cteamng Facility (4)
Electrical Equipment 42)
Electricity Generation via Combustion (4)
Electroplating, Plating. Polishing, Anodizing, & Coloring (2)
<*) Fabricated Metal Products (2)
;;^ Flexible Polyurethane Foam Production (1)
e
*
E
F
IT
A
it
ffl
*
*
o
10 mile radius I
Toed Proce&&inaYArjricultLir.e (1C)
Gasoline/Diesel Service Station 42}
Grain Handling (?)
Heating Equipms-nt Manufacturing (T)
HospilaUl)
Hat Mix Asphuii Plan! i-i-
IrtrJustnal Macriinery and Equipmenl (1)
Inslitulional - prison (1)
Inslilulional - school <7J
Iron and Sleel Foundry (1)
Landfill (3)
Leather and Leather Products 41)
Marine Port 4 5)
Military Base/National Security Facilrty (1)
Mine/Quarry (6)
Mineral Products (1)
Miscellaneous CommerclaVlndustfral (25)
County boundary
M Miscellaneous Manufacturing (12)
Oil and/or Gas Production (3)
_ Pharmaceutical Manufacturing (2)
1 Pnmary Metal Production (4)
f Prinlltg. Coaling SDyeng of Fabric ID
P Pnnting/Purjlisning (5)
H Pulp and Paper PlanlMttod ProOucts (2)
R Rubber and Miscellaneous Plastics Products (2)
2 Secondary Metal Processing (2)
< Srte Remediation Actwlty (1)
> Solid Waste Disposal Commerctal/lnsritulional (2)
Y Steel Mill (3)
S Surface Coabng (8)
TT Telecommunications (1)
T Textile Mill (2)
$ Transportation and Marketing of Petroleum Products (3)
> V&slewater Treatment (5)
16-3
-------
Table 16-1. Geographical Information for the Missouri Monitoring Site
Site
Code
S4MO
AQS Code
29-510-0085
Location
St. Louis
County
St. Louis
City
Micro- or
Metropolitan
Statistical Area
St. Louis, MO-IL
MSA
Latitude
and
Longitude
38.656436,
-90.198661
Land Use
Residential
Location
Setting
Urban/City
Center
Additional Ambient Monitoring Information1
CO, O3, Meteorological parameters, PM10, Black
carbon, PM2 5, PM25 Speciation, SO2, NOy, NO.
BOL D ITALICS = EPA-designaled NATTS Site
-------
S4MO is located in central St. Louis. Figure 16-1 shows that the S4MO monitoring site is
located less than 1/4 mile west of 1-70. The Mississippi River, which separates Missouri and
Illinois, is less than 1 mile east of the site. Although the area directly around the monitoring site
is primarily residential, industrial facilities are located just on the other side of 1-70. Figure 16-2
shows that a large number of point sources are located within 10 miles of S4MO. The source
categories with the greatest number of point sources surrounding S4MO include aircraft
operations, which include airports as well as small runways, heliports, or landing pads; food
processing facilities; and concrete batch plants. In the immediate vicinity of S4MO are a
pharmaceutical manufacturing facility and a printing and publishing facility.
Table 16-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Missouri monitoring site. Table 16-2 includes county-level
population and vehicle registration information. Table 16-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within the monitoring site's residing county. In addition, the population within 10 miles
of the site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding the monitoring site. Table 16-2 also
contains traffic volume information for S4MO. Finally, Table 16-2 presents the county-level
daily VMT for S4MO. Note that because the state of Missouri provides data within the city of
St. Louis separately from St. Louis County, Table 16-2 includes the combination of the city and
county data for county-level statistics in order to compare these statistics with other sites'
county-level data.
Table 16-2. Population, Motor Vehicle, and Traffic Information for the Missouri
Monitoring Site
Site
S4MO
Estimated
County
Population1
1,316,761
County-level
Vehicle
Registration2
1,114,812
Vehicles per
Person
(Registration:
Population)
0.85
Population
within 10
miles3
796,065
Estimated
10-mile
Vehicle
Ownership
673,974
Annual
Average
Daily
Traffic4
79,558
County-
level Daily
VMT5
23,333,850
Bounty-level population estimate reflects county and city 2011 data from the U.S. Census Bureau (Census
Bureau, 2012b)
2Vehicle registration reflects county and city 2011 data from the Missouri Dept of Revenue (MO DOR, 2012)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the Missouri DOT (MO DOT, 2011)
5VMT reflects county and city 2011 data for all public roads from the Missouri DOT (MO DOT, 2013)
BOLD ITALICS = EPA-designated NATTS Site
16-5
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Observations from Table 16-2 include the following:
S4MO's county-level population and vehicle registration rank 10th compared to other
counties with NMP sites. The 10-mile population and vehicle ownership estimates for
S4MO are in the middle third compared to other sites.
The vehicle-per-person ratio is also in the middle of the range compared to other
NMP sites.
The traffic volume experienced near S4MO ranks 19th among other NMP sites. The
traffic estimate provided is for 1-70 near Exit 249.
The St. Louis City and County daily VMT ranks 12th among counties with NMP sites
(where VMT data were available).
16.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Missouri on sample days, as well as over the course of the year.
16.2.1 Climate Summary
The city of St. Louis is located along the Mississippi River, which acts as Missouri's
eastern border. St. Louis has a climate that is continental in nature, with cold, dry winters; warm,
somewhat wetter summers; and significant seasonal variability. Warm, moist air flowing
northward from the Gulf of Mexico alternating with cold, dry air marching southward from
Canada and the northern U.S. result in weather patterns that do not persist for very long. The
City of St. Louis experiences the urban heat island effect, retaining more heat within the city than
outlying areas (Bair, 1992 and MCC, 2013).
16.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station is located at St. Louis Downtown Airport
(WBAN 03960). Additional information about this weather station, such as the distance between
the site and the weather station, is provided in Table 16-3. These data were used to determine
how meteorological conditions on sample days vary from conditions experienced throughout the
year.
16-6
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Table 16-3. Average Meteorological Conditions near the Missouri Monitoring Site
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
From Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
St. Louis, Missouri - S4MO
St. Louis
Downtown
Airport
03960
(38.57, -90.16)
6.27
miles
156ฐ
(SSE)
Sample
Day
2011
64.8
ฑ5.3
66.5
ฑ2.1
55.6
ฑ4.9
56.7
ฑ1.9
44.7
ฑ4.7
46.0
ฑ1.8
50.0
ฑ4.4
51.1
ฑ1.7
69.7
ฑ3.0
70.5
ฑ1.2
1016.4
ฑ 1.8
1015.9
ฑ0.7
6.3
ฑ0.7
5.8
ฑ0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Table 16-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 16-3 is the
95 percent confidence interval for each parameter. Although average meteorological conditions
on sample days are not statistically different than the average meteorological conditions
throughout 2011, temperatures do appear slightly cooler on sample days, as shown in Table 16-3.
This is likely the result of five additional days in December 2011 when make-up samples were
collected.
16.2.3 Back Trajectory Analysis
Figure 16-3 is the composite back trajectory map for days on which samples were
collected at the S4MO monitoring site in 2011. Included in Figure 16-3 are four back trajectories
per sample day. Figure 16-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 16-3 and 16-4 represents 100 miles.
16-8
-------
Figure 16-3. 2011 Composite Back Trajectory Map for S4MO
Figure 16-4. Back Trajectory Cluster Map for S4MO
16-9
-------
Observations from Figures 16-3 and 16-4 for S4MO include the following:
Back trajectories originated from a variety of directions at S4MO, although back
trajectories from the northwest and south-southeast to south-south west were most
common.
The 24-hour air shed domain for S4MO is similar in size to other NMP sites. The
farthest away a back trajectory originated was greater than 800 miles, over northern
North Dakota. However, the average trajectory length was 239 miles and most back
trajectories (87 percent) originated within 400 miles of the monitoring site.
The cluster analysis shows that many (32 percent) back trajectories originated to the
south to southwest of S4MO, although of varying lengths. Another 20 percent of back
trajectories originated to the southeast to south of S4MO. Thus, greater than
50 percent of back trajectories originated from a direction with a southerly
component.
The longest back trajectories originated to the northwest and north of the site. Twenty
percent of back trajectories originated to the northwest of S4MO. Another five
percent originated to the north over Wisconsin and the Great Lakes.
Back trajectories originating from the east or the west tended to be shorter in length.
The cluster trajectory originating to the west of S4MO (13 percent) represents back
trajectories originating over the state of Missouri. The cluster trajectory originating to
the northeast of S4MO (12 percent) represents back trajectories that originate over the
states of Illinois and Indiana.
16.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at St. Louis Downtown Airport
near S4MO were uploaded into a wind rose software program to produce customized wind roses,
as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions using
"petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 16-5 presents a map showing the distance between the NWS station and S4MO,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 16-5 also presents three different wind roses for the
S4MO monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
16-10
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presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
Observations from Figure 16-5 for S4MO include the following:
The St. Louis Downtown Airport weather station is located approximately 6.3 miles
south-southeast of S4MO. The weather station location is across the Mississippi River
and state border in Illinois.
The historical wind rose shows that winds from the southeast, south-southeast, and
south were frequently observed near S4MO. Winds from these directions account for
approximately 28 percent of observations. Calm winds (<2 knots) were observed for
approximately 19 percent of the hourly wind measurements. Winds from the west to
northwest to north account for the bulk of the remaining wind observations. The
strongest winds were from the west to northwest.
The wind patterns shown on the 2011 wind rose generally resemble those shown on
the historical wind rose, although there were fewer southeasterly winds and more
southerly winds.
The sample day wind patterns also resemble the historical and full-year wind patterns,
although there was a higher percentage of south-southeasterly winds and slightly
fewer calm winds.
The similarities in the wind patterns between the wind roses indicate that wind
conditions on sample days were similar to wind conditions experienced throughout
2011 and historically.
16-11
-------
Figure 16-5. Wind Roses for the St. Louis Downtown Airport Weather Station near S4MO
Distance between S4MO and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
16-12
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16.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for S4MO in order to allow analysts
and readers to focus on a subset of pollutants through the context of risk. Each pollutant's
preprocessed daily measurement was compared to its associated risk screening value. If the
concentration was greater than the risk screening value, then the concentration "failed the
screen." Pollutants of interest are those for which the individual pollutant's total failed screens
contribute to the top 95 percent of the site's total failed screens. In addition, if any of the NATTS
MQO Core Analytes measured by the monitoring site did not meet the pollutant of interest
criteria based on the preliminary risk-based screening, that pollutant was added to the list of site-
specific pollutants of interest. A more in-depth description of the risk-based screening process is
presented in Section 3.2.
Table 16-4 presents the results of the preliminary risk-based screening process for S4MO.
The pollutants that failed at least one screen and contributed to 95 percent of the total failed
screens for the monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. S4MO sampled for VOCs, PAHs, carbonyl
compounds, metals (PMio), and hexavalent chromium.
Observations from Table 16-4 include the following:
Twenty-five pollutants, of which 13 are NATTS MQO Core Analytes, failed at least
one screen for S4MO. S4MO failed the greatest number of screens among all NMP
sites.
Formaldehyde, acetaldehyde, and benzene were detected in every carbonyl compound
or VOC sample collected and failed 100 percent of screens for S4MO. Other
pollutants also failed 100 percent of screens but were detected less frequently:
1,3-butadiene, 1,2-dichloroethane, hexachloro-1,3-butadiene, 1,2-dibromoethane,
1,1,2,2-tetrachloroethane, and chloromethylbenzene. With the exception of
1,3-butadiene, these pollutants were detected in only a few samples.
Sixteen pollutants were identified as pollutants of interest for S4MO based on the
risk-based screening process; of these, 10 are NATTS MQO Core Analytes. Three
additional pollutants (nickel, hexavalent chromium, and chloroform) were added to
S4MO's pollutants of interest because they are NATTS MQO Core Analytes, even
though they did not contribute to 95 percent of S4MO's failed screens. Five more
pollutants (beryllium, benzo(a)pyrene, tetrachloroethylene, trichloroethylene, and
vinyl chloride) were also added to S4MO's pollutants of interest because they are
NATTS MQO Core Analytes, even though they did not fail any screens. These five
16-13
-------
pollutants are not shown in Table 16-4 but are shown in subsequent tables in the
sections that follow.
Table 16-4. Risk-Based Screening Results for the Missouri Monitoring Site
Pollutant
Screening
Value
(Hg/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
St. Louis, Missouri - S4MO
Acetaldehyde
Formaldehyde
Naphthalene
Arsenic (PM10)
Benzene
Carbon Tetrachloride
1,3-Butadiene
Manganese (PM10)
ฃ>-Dichlorobenzene
Cadmium (PM10)
1 ,2-Dichloroethane
Ethylbenzene
Acenaphthene
Fluorene
Lead (PM10)
Hexachloro- 1 ,3 -butadiene
1 ,2-Dibromoethane
Nickel (PM10)
1 , 1 ,2,2-Tetrachloroethane
Propionaldehyde
Chloromethylbenzene
Hexavalent Chromium
Carbon Bisulfide
Chloroform
1 , 1 ,2-Trichloroethane
0.45
0.077
0.029
0.00023
0.13
0.17
0.03
0.005
0.091
0.00056
0.038
0.4
0.011
0.011
0.015
0.045
0.0017
0.0021
0.017
0.8
0.02
0.000083
70
9.8
0.0625
Total
59
59
59
57
57
56
52
44
29
20
18
15
12
12
12
11
7
6
6
4
2
2
1
1
1
602
59
59
61
59
57
57
52
59
47
59
18
57
61
61
59
11
7
59
6
59
2
60
57
44
2
1,132
100.00
100.00
96.72
96.61
100.00
98.25
100.00
74.58
61.70
33.90
100.00
26.32
19.67
19.67
20.34
100.00
100.00
10.17
100.00
6.78
100.00
3.33
1.75
2.27
50.00
53.18
9.80
9.80
9.80
9.47
9.47
9.30
8.64
7.31
4.82
3.32
2.99
2.49
1.99
1.99
1.99
1.83
1.16
1.00
1.00
0.66
0.33
0.33
0.17
0.17
0.17
9.80
19.60
29.40
38.87
48.34
57.64
66.28
73.59
78.41
81.73
84.72
87.21
89.20
91.20
93.19
95.02
96.18
97.18
98.17
98.84
99.17
99.50
99.67
99.83
100.00
16.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Missouri monitoring site. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for S4MO, where the data meet the applicable criteria.
Concentration averages for select pollutants are also presented graphically to illustrate how the
site's concentrations compare to the program-level averages, as presented in Section 4.1. In
16-14
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addition, concentration averages for select pollutants are presented from previous years of
sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for S4MO are provided in Appendices J, L, M, N, and O.
16.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for the Missouri site, as described in Section 3.1. The quarterly average of a particular pollutant
is simply the average concentration of the preprocessed daily measurements over a given
calendar quarter. Quarterly average concentrations include the substitution of zeros for all non-
detects. A site must have a minimum of 75 percent valid samples of the total number of samples
possible within a given quarter for a quarterly average to be calculated. An annual average
includes all measured detections and substituted zeros for non-detects for the entire year of
sampling. Annual averages were calculated for pollutants where at least three valid quarterly
averages could be calculated and where method completeness was greater than or equal to
85 percent, as presented in Section 2.4. Quarterly and annual average concentrations for S4MO
are presented in Table 16-5, where applicable. Note that concentrations of the PAHs, metals, and
hexavalent chromium are presented in ng/m3 for ease of viewing. Also note that if a pollutant
was not detected in a given calendar quarter, the quarterly average simply reflects "0" because
only zeros substituted for non-detects were factored into the quarterly average concentration.
Table 16-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Missouri Monitoring Site
Pollutant
#of
Measured
Detections vs.
# of Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
St. Louis, Missouri - S4MO
Acetaldehyde
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
59/59
57/57
52/57
57/57
44/57
2.47
ฑ0.42
0.89
ฑ0.14
0.10
ฑ0.03
0.51
ฑ0.06
0.12
ฑ0.06
3.14
ฑ0.80
0.69
ฑ0.07
0.06
ฑ0.02
0.60
ฑ0.04
0.19
ฑ0.15
3.97
ฑ1.03
0.76
ฑ0.09
0.07
ฑ0.02
0.71
ฑ0.06
1.00
ฑ1.67
1.31
ฑ0.25
0.86
ฑ0.15
0.11
ฑ0.03
0.63
ฑ0.10
0.09
ฑ0.04
2.75
ฑ0.43
0.80
ฑ0.06
0.08
ฑ0.01
0.61
ฑ0.04
0.35
ฑ0.40
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
16-15
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Table 16-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Missouri Monitoring Site (Continued)
Pollutant
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Hexachloro- 1 , 3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Acenaphthene3
Arsenic (PM10)a
Benzo(a)pyrenea
Bery Ilium (PM10)a
Cadmium (PM10)a
Fluorene a
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
#of
Measured
Detections vs.
# of Samples
47/57
18/57
57/57
59/59
11/57
55/57
25/57
8/57
61/61
59/59
59/61
59/59
59/59
61/61
60/61
59/59
59/59
61/61
59/59
1st
Quarter
Average
(Hg/m3)
0.21
ฑ0.21
0.02
ฑ0.02
0.41
ฑ0.10
5.30
ฑ2.97
0.04
ฑ0.04
0.19
ฑ0.07
0.04
ฑ0.02
0.01
ฑ0.01
1.69
ฑ0.61
0.78
ฑ0.28
0.16
ฑ0.05
0.01
ฑ0.01
0.60
ฑ0.32
2.54
ฑ0.64
0.03
ฑ0.02
9.53
ฑ3.57
7.27
ฑ2.07
74.38
ฑ 27.68
1.00
ฑ0.19
2nd
Quarter
Average
(Ug/m3)
0.12
ฑ0.09
0.05
ฑ0.03
0.27
ฑ0.04
4.57
ฑ1.56
0.01
ฑ0.02
0.16
ฑ0.03
0.02
ฑ0.02
0.01
ฑ0.01
5.87
ฑ2.40
0.81
ฑ0.18
0.10
ฑ0.05
0.01
ฑ0.01
0.63
ฑ0.19
6.66
ฑ2.58
0.04
ฑ0.01
10.81
ฑ3.27
41.50
ฑ52.71
61.09
ฑ 16.32
1.53
ฑ0.46
3rd
Quarter
Average
(Ug/m3)
0.39
ฑ0.41
0.01
ฑ0.02
0.37
ฑ0.05
5.43
ฑ1.65
0.01
ฑ0.02
0.15
ฑ0.04
0.04
ฑ0.03
0.01
ฑ0.01
10.71
ฑ3.79
0.90
ฑ0.21
0.07
ฑ0.02
0.01
ฑ0.01
0.51
ฑ0.23
11.28
ฑ3.78
0.03
ฑ0.01
10.55
ฑ3.63
12.67
ฑ4.57
106.70
ฑ25.01
1.20
ฑ0.79
4th
Quarter
Average
(Ug/m3)
0.14
ฑ0.09
0.04
ฑ0.03
0.46
ฑ0.09
1.76
ฑ0.36
0.03
ฑ0.04
0.20
ฑ0.14
0.04
ฑ0.02
0.01
ฑ0.01
3.66
ฑ2.05
1.00
ฑ0.45
0.18
ฑ0.07
0.01
ฑ0.01
0.49
ฑ0.24
4.18
ฑ1.57
0.03
ฑ0.01
10.67
ฑ4.07
11.13
ฑ4.63
88.28
ฑ21.76
1.05
ฑ0.45
Annual
Average
(Ug/m3)
0.21
ฑ0.11
0.03
ฑ0.01
0.38
ฑ0.04
4.25
ฑ0.92
0.02
ฑ0.01
0.18
ฑ0.04
0.03
ฑ0.01
0.01
ฑ0.01
5.41
ฑ1.45
0.87
ฑ0.14
0.13
ฑ0.03
0.01
ฑ0.01
0.56
ฑ0.12
6.08
ฑ1.40
0.03
ฑ0.01
10.42
ฑ1.72
18.42
ฑ 13.18
83.82
ฑ11.75
1.20
ฑ0.26
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
Observations for S4MO from Table 16-5 include the following:
The pollutants with the highest annual average concentrations by mass are
formaldehyde (4.25 ฑ 0.92 |ig/m3) and acetaldehyde (2.75 ฑ 0.43 |ig/m3). These are
the only pollutants of interest with annual averages greater than 1 |ig/m3.
16-16
-------
The first, second, and third quarter average formaldehyde concentrations are
significantly higher than the fourth quarter average and their confidence intervals
reflect a relatively high-level of variability in the measurements. Concentrations of
formaldehyde ranged from 0.714 |ig/m3to 17.8 |ig/m3. The two highest
concentrations were measured on back-to-back sample days in February. Four
concentrations greater than 10 |ig/m3 were measured at S4MO and at least one was
measured in each quarter except the fourth quarter. Conversely, the six lowest
measurements of formaldehyde were all measured during the fourth quarter of 2011.
The confidence interval for chloroform is greater than the annual average
concentration it is associated with, indicating that there are likely outliers affecting
this average. A review of the quarterly averages shows that any outliers were likely
measured during the third quarter of 2011. The maximum chloroform concentration
was measured at S4MO on July 8, 2011 (11.5 |ig/m3). The next highest concentration
measured at S4MO is an order of magnitude less (1.17 |ig/m3). S4MO is the only site
besides NBIL with a chloroform concentration greater than 10 |ig/m3.
The confidence intervals associated with the first and third quarter averages of
/>-dichlorobenzene are greater than or equal to the averages themselves, indicating the
likely influence of outliers. A review of the data shows that the maximum
/>-dichlorobenzene concentrations were measured in September (2.83 |ig/m3) and
January (1.50 |ig/m3). These are the two highest/>-dichlorobenzene concentrations
measured across all NMP sites sampling VOCs and represent two of the four
concentrations of />-dichlorobenzene greater than 1 |ig/m3 measured across the
program. For perspective, the median/>-dichlorobenzene concentration for S4MO is
0.096 |ig/m3.
The quarterly averages of several of the VOCs (benzene, 1,3-butadiene, ethylbenzene,
and tetrachloroethylene) appear to be higher during the colder months of the year.
However, the confidence intervals indicate that the differences between the quarterly
averages are not statistically significant.
The metals sampler was changed in July 2011, and Teflonฎ filters were used to
collect metals samples rather than quartz filters. It does not appear that the
instrumentation and filter changes resulted in a significant difference in the quarterly
averages of the metals.
Manganese has the highest annual average concentration among the PMio metals
measured at S4MO. The confidence interval associated with this annual average
indicates a high level of variability within the measurements. The second quarter
average is more than three times higher than the next highest quarterly average
concentration. Further, the confidence interval for the second quarter average is
greater than the average concentration itself. A review of the data shows that the
maximum concentration of manganese was measured on June 2, 2011 (395 ng/m3)
and is the maximum manganese concentration measured among all NMP sites
sampling metals. This measurement is three times greater than the next highest
concentration of manganese measured across the program (130 ng/m3, measured at
PXSS) and six times greater than the next highest concentration of manganese
16-17
-------
measured at S4MO (65.3 ng/m3). For perspective, the median manganese
concentration for S4MO is 10.0 ng/m3.
Naphthalene has the highest annual average concentration among the PAHs measured
at S4MO. The confidence intervals calculated for the naphthalene averages indicate
that there is a high level of variability in the measurements. Concentrations of
naphthalene measured at S4MO range from 18.0 ng/m3 to 238 ng/m3 with a median
concentration of 72.2 ng/m3.
Concentrations of acenaphthene and fluorene appear to be highest during the warmer
months of the year, particularly the third quarter of 2011. The averages for these
quarters have relatively large confidence intervals associated with them. A review of
the data shows that the maximum concentration of each pollutant was measured on
July 2, 2011 (31.8 ng/m3 and 31.4 ng/m3, respectively). The July 2nd concentrations
are almost twice the next highest concentrations measured at S4MO, which were
measured on the same date in June. Of the concentrations of each pollutant greater
than 10 ng/m3, the majority were measured during the third quarter, followed by the
second quarter. Of the concentrations less than 2 ng/m3, the measurements were
evenly split between the first and fourth quarters.
At the beginning of 2013, the Missouri Department of Natural Resources discovered
that a sampler contamination issue resulted in artificially elevated concentrations of
acrylonitrile from September 2010 through October 2012. Thus, the acrylonitrile
results from this time period were invalidated, which includes all of the results for
2011.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for S4MO from
those tables include the following:
S4MO appears in Tables 4-9 through 4-12 a total of 21 times, the most of any NMP
site.
S4MO is listed among the sites with the highest annual average concentrations of all
VOCs except benzene and 1,3-butadiene. S4MO has the highest annual average
concentration of hexachloro-1,3-butadiene and the second highest annual average
concentrations of 1,2-dichloroethane and/>-dichlorobenzene. This site also has the
fourth highest annual average concentration of chloroform.
S4MO has the second highest annual average concentration of formaldehyde and the
third highest annual average concentration of acetaldehyde.
S4MO's annual average concentration of benzo(a)pyrene ranks sixth highest among
NMP sites sampling PAHs. This site's annual average acenaphthene and fluorene
concentrations each rank seventh among NMP sites sampling PAHs.
16-18
-------
S4MO has the highest annual average concentrations of arsenic, cadmium, and lead
among NMP sites sampling PMio metals (and those sampling TSP metals). This site's
annual average concentration of manganese ranked second among NMP sites
sampling PMio metals.
16.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde, arsenic,
benzene, benzo(a)pyrene, 1,3-butadiene, formaldehyde, hexavalent chromium, lead, manganese,
and naphthalene were created for S4MO. Figures 16-6 through 16-15 overlay the site's
minimum, annual average, and maximum concentrations onto the program-level minimum, first
quartile, median, average, third quartile, and maximum concentrations, as described in
Section 3.5.3.
Figure 16-6. Program vs. Site-Specific Average Acetaldehyde Concentration
S4MO
Concentration (|
Program: 1st Quartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site: Site Average Site Minimum/Maximum
Figure 16-7. Program vs. Site-Specific Average Arsenic (PMio) Concentration
16
S4P/0
0.5
2 2.5
Concentration (ng/m3)
3.5
4.5
Program
Site:
: 1st Quartile
Site Average
o
2nd Quartile 3rd Quartile 4th Quartile Ave
n
Site Minimum/Maximum
'rage
16-19
-------
Figure 16-8. Program vs. Site-Specific Average Benzene Concentration
S4f,'C
j Program Max Concentration = 23.8
45
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
10
Figure 16-9. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
0.75 1 1.15
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 16-10. Program vs. Site-Specific Average 1,3-Butadiene Concentration
Program Max Concentration = 9.51
5.5
1.5
Concentration (jig/mi)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
16-20
-------
Figure 16-11. Program vs. Site-Specific Average Formaldehyde Concentration
S4f,'C
10 15
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 16-12. Program vs. Site-Specific Average Hexavalent Chromium Concentration
S4f/C
0.05
5.1
0.15
Concentration (ng/m3)
0.2
DL25
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 16-13. Program vs. Site-Specific Average Lead (PMi0) Concentration
S4f,'C
-u-
10
15 20
Concentration (ng/m3)
25
30
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
35
16-21
-------
Figure 16-14. Program vs. Site-Specific Average Manganese (PMi0) Concentration
S4P/0
n
; Program Max Concentration = 395 ng/m3
;
100 125
Concentration (ng/mi)
150
17E
200
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 16-15. Program vs. Site-Specific Average Naphthalene Concentration
S4f/C
Program Max Concentration = 779 ng/m3
50
100
is:
200 250 300
Concentration (ng/mi)
35:
400
45:
Program:
Site:
IstQuartile 2ndC
Site Average Site l\
o
Observations from Figures 16-6 through 16-15 include the following:
Figure 16-6 shows that S4MO's annual average acetaldehyde concentration is
greater than the program-level average and third quartile. Although the maximum
concentration measured at S4MO is not the maximum concentration measured
across the program, it is the fifth highest acetaldehyde concentration measured
among NMP sites sampling this pollutant. There were no non-detects of
acetaldehyde measured at S4MO or across the program.
Figure 16-7 shows that S4MO's annual average arsenic (PMio) concentration is
greater than the program-level average and third quartile. Recall from the
previous section that this site has the highest annual average arsenic concentration
among NMP sites sampling metals. The maximum concentration measured at
S4MO is the second highest concentration measured across the program. There
were no non-detects of arsenic measured at S4MO.
Figure 16-8 is the box plot for benzene. Note that the program-level maximum
concentration (23.8 |ig/m3) is not shown directly on the box plot because the scale
of the box plot would be too large to readily observe data points at the lower end
of the concentration range. Thus, the scale has been reduced to 10 |ig/m3.
Figure 16-8 for benzene shows that the annual average benzene concentration for
S4MO is less than the program-level average concentration but greater than the
program-level median concentration. The maximum benzene concentration
16-22
-------
measured at S4MO is considerably less than the maximum concentration
measured at the program level. There were no non-detects of benzene measured at
S4MO or across the program.
Figure 16-9 is the box plot for benzo(a)pyrene. Note that the first quartile for this
pollutant is zero and is not visible on this box plot. This box plot shows that the
annual average concentration for S4MO is greater than the program-level average
and third quartile. Recall from the previous section that the annual average
concentration for S4MO ranked third among sites sampling benzo(a)pyrene.
Figure 16-9 also shows that the maximum concentration measured at S4MO is
less than the maximum concentration measured across the program. Two non-
detects of benzo(a)pyrene were measured at S4MO.
Similar to the benzene graph, the program-level maximum 1,3-butadiene
concentration (9.51 |ig/m3) is not shown directly on the box plot as the scale has
been reduced to 3 |ig/m3 to allow for the observation of data points at the lower
end of the concentration range. Figure 16-10 for 1,3-butadiene shows that the
annual average concentration for S4MO is less than the program-level average
concentration but greater than the program-level median concentration. The
maximum concentration measured at S4MO is considerably less than the
maximum concentration measured across the program. There were a few non-
detects of 1,3-butadiene measured at S4MO.
Figure 16-11 for formaldehyde shows that the annual average concentration for
S4MO is greater than the program-level average concentration as well as the
program-level third quartile. The maximum formaldehyde concentration
measured at S4MO is less than the maximum concentration measured across the
program but ranks sixth highest among sites sampling formaldehyde. There were
no non-detects of formaldehyde measured at S4MO or across the program.
Figure 16-12 shows that the annual average concentration of hexavalent
chromium for S4MO is greater than both the program-level average concentration
and program-level third quartile. The maximum concentration measured at S4MO
is less than the program-level maximum concentration. A single non-detect of
hexavalent chromium was measured at S4MO.
Figure 16-13 shows that S4MO's annual average lead (PMio) concentration is
more than double the program-level average concentration. Recall from the
previous section that this site has the highest annual average lead concentration
among sites sampling metals. In addition, the maximum lead concentration
measured at S4MO is the maximum concentration measured across the program.
There were no non-detects of lead measured at S4MO or across the program.
Figure 16-14 is the box plot for manganese (PMio). Note that the program-level
maximum concentration (395 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 200 ng/m3 to allow for the observation of data points at
the lower end of the concentration range. Figure 16-14 shows that S4MO's annual
average manganese (PMio) concentration is greater than both the program-level
16-23
-------
average concentration and third quartile. Recall from the previous section that this
site has the second highest annual average manganese concentration among sites
sampling PMio metals. The maximum concentration of manganese measured at
S4MO is the maximum concentration measured across the program. There were
no non-detects of manganese measured at S4MO or across the program.
Figure 16-15 is the box plot for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 500 ng/m3 to allow for the observation of data points at
the lower end of the concentration range. Figure 16-15 shows that the annual
average naphthalene concentration for S4MO is just greater than the program-
level average concentration. The maximum naphthalene concentration measured
at S4MO is less than the program-level maximum concentration. There were no
non-detects of naphthalene measured at S4MO or across the program.
16.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. S4MO has sampled VOCs and carbonyl compounds under the NMP since 2002,
PMio metals since 2003, and hexavalent chromium since 2005. Thus, Figures 16-16 through
16-23 present the annual statistical metrics for acetaldehyde, arsenic, benzene, 1,3-butadiene,
formaldehyde, hexavalent chromium, lead, and manganese (respectively) for S4MO. The
statistical metrics presented for assessing trends include the substitution of zeros for non-detects.
S4MO began sampling PAHs under the NMP in 2008; therefore, the trends analysis was not
conducted for the PAHs.
16-24
-------
Figure 16-16. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at S4MO
1
Concentration
I
3
r
^^
r
* T
n f , ^U
* ... "^ [ ^.
^] p-| 'ง .i. -Li ....Ly" r"1 W
t L-rJ !53 ^^ L-^-l
2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Max mum 95th Percentile "^"Average
Figure 16-17. Annual Statistical Metrics for Arsenic (PMio) Concentrations
Measured at S4MO
- Minimum Median - Maximum 95th Percentile # 5th Percentile .. 4.. Average
16-25
-------
Figure 16-18. Annual Statistical Metrics for Benzene Concentrations
Measured at S4MO
ST
jncent ratio
O H
|
< 3 _
+ ..
.
r T
i
r ^^ r
r-l-, i
nn
"""^-- r^n
' ' 1 ' ^ ^^ ซ-
-r UjJ ^ Lj-l I
2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Pe re entile Minimum Median Max mum * 95th Percentile ..^.. Average
Figure 16-19. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at S4MO
2003 2004 2005 2006
2007 2003
Year
2009 2010
SthPercentile - Minimum Median Maximum 95thPercentile *** Average
16-26
-------
Figure 16-20. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at S4MO
J 30 -
E
.a
c
i
a
S
<
5 -
0 -1
T
_pU_
I
I
r
r r I
^ - r
-L^ * rH i c i
f-1 a-1 ^^ > -" 1 -
2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
4 5th Pe re entile Minimum Median Max mum * 95th Percentile ..^.. Average
Figure 16-21. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at S4MO
E
.1
1
i
& 02
2 0.2
ฃ
<
T
2005
5th Percentile
2006
r
2007
- Minimum
T
T
^
. . r
2008 2009 2010 2011
Year
Median - Maximum 95th Percentile ..+.. Average
16-27
-------
Figure 16-22 Annual Statistical Metrics for Lead (PMi0) Concentrations
Measured at S4MO
nation iii|T/nil.
: ง
Average Concen
i i
+ "
2004
0
_L
2305
5th Percentile
2006
- M
nimum
1337
Year
Median
1 |
2008
Maximum
[
_*__ ijjfc.
E
2009 2010 2011
* 95th Percentile ..+.. Average
Figure 16-23. Annual Statistical Metrics for Manganese (PMio) Concentrations
Measured at S4MO
___
(ration (ng/i
i i
s
3
^
J
The maximum
concentrationfor
2008 is 734 ng/nn3
I
I
k--- ...
2004 2005
I
2006
Minimum Median
T
IPI
2007
Year
Maximum
3_
" | 1 |
^ ^^n.
2008 2009
2010
95th Percentile 5th Percentile ..*..
M
3
>
2011
Average
16-28
-------
Observations from Figure 16-16 for acetaldehyde include the following:
Because carbonyl compound sampling did not begin until December 2002, 2002 data
were excluded from this analysis.
The maximum acetaldehyde concentration was measured in 2004 and is more than
twice the next highest concentration (measured in 2007).
Even with the maximum concentration measured in 2004, nearly all of the statistical
metrics decreased from 2003 to 2004. The maximum concentration measured in 2004
(32.5 |ig/m3) is nearly six times higher than the next highest concentration
(5.72 |ig/m3) measured in 2004 and the median concentration for that year is
2.91 |ig/m3.
The average concentrations have an undulating pattern in Figure 16-16 and have
fluctuated between 1.83 |ig/m3 (2008) and 4.10 |ig/m3 (2010).
Even though the maximum, 95th percentile, and average concentrations increased
from 2005 to 2006, the median concentration actually decreased. Although there were
four concentrations greater than 6 |ig/m3 measured in 2006, the number of
concentrations less than 3 |ig/m3 increased from 36 in 2005 to 47 in 2006.
After a significant decrease from 2007 to 2008, the average acetaldehyde
concentration began increasing. The average concentration for 2010 is the maximum
average concentration shown across the years of sampling. A significant decrease is
shown from 2010 to 2011.
The minimum concentration measured is greater than zero for all years shown,
indicating that there were no non-detects reported for acetaldehyde.
Observations from Figure 16-17 for arsenic include the following:
S4MO began sampling metals in July 2003. Because fewer than 85 percent of
possible samples were collected in 2003, Figure 16-17 excludes data from 2003.
The maximum arsenic concentration was measured on December 26, 2007. Only five
concentrations greater than 10 ng/m3 have been measured at S4MO since 2004.
There is a slight downward trend in the average concentration of arsenic at S4MO,
but the magnitude of the outliers measured in 2005, 2007, and 2009 makes this
difficult to see. In addition, confidence intervals calculated for the average
concentrations are relatively large as a result of the highest concentrations and
indicate that these changes are not statistically significant.
Many of the statistical parameters are at a minimum for 2011.
16-29
-------
Although difficult to discern in Figure 16-17, the minimum concentration measured is
greater than zero for all years shown, indicating that there were no non-detects
reported for arsenic.
Observations from Figure 16-18 for benzene measurements include the following:
Because VOC sampling did not begin until December 2002, 2002 data was excluded
from this analysis.
All four benzene concentrations greater than 5 ug/m3 were measured in 2003.
The average concentrations exhibit an overall decreasing trend through 2007,
representing a greater than 1 ug/m3 decrease, although the most significant changes
occurred in the early years of sampling. The average concentration has varied
between 0.80 ug/m3 (2011) and 1.03 ug/m3 (2010) since 2007.
The range of benzene measurements is smallest for 2011, with a difference of
approximately 1 ug/m3 between the minimum and maximum concentration measured.
The minimum concentration measured is greater than zero for each year, indicating
that there were no non-detects reported for benzene since 2003.
Observations from Figure 16-19 for 1,3-butadiene include the following:
The maximum 1,3-butadiene concentration was measured at S4MO in 2003, although
a similar concentration was also measured in 2008. These are the only two
1,3-butadiene concentrations greater than 1.0 ug/m3 that have been measured at
S4MO.
The minimum, 5th percentile, and median concentrations are all zero for 2003 and
2004, indicating that at least 50 percent of the measurements were non-detects. The
number of non-detects decreased after 2004, from a maximum of 66 percent in 2004
to a minimum of zero percent in 2010.
Between 2004 and 2008, the average concentration changed very little, ranging from
0.079 ug/m3 (2005) to 0.095 ug/m3 (2006). Greater fluctuations are shown in the
years that follow.
Observations from Figure 16-20 for formaldehyde include the following:
The maximum formaldehyde concentration (43.8 ug/m3) was measured in 2004 on
the same day that the maximum acetaldehyde concentration was measured
(August 31, 2004). This concentration is more than twice the next highest
concentration (17.8 ug/m3), which was measured in 2011. The six highest
concentrations of formaldehyde were all measured in 2004 (2) or 2011 (4). Overall,
21 measurements of formaldehyde greater than 10 ug/m3 have been measured at
S4MO.
16-30
-------
The average concentration has fluctuated over the years of sampling, ranging between
2.46 |ig/m3 (2009) and 5.10 |ig/m3 (2004).
The average formaldehyde concentration increased significantly from 2010 to 2011.
There were 11 concentrations of formaldehyde in 2011 that were greater than the
maximum concentration for 2010.
The minimum concentration measured for each year is greater than zero, indicating
that there were no non-detects of formaldehyde reported over the years shown.
Observations from Figure 16-21 for hexavalent chromium include the following:
The maximum hexavalent chromium concentration was measured on July 5, 2008
(0.460 ng/m3), although a similar concentration was also measured on July 4, 2006
(0.422 ng/m3). The third highest hexavalent chromium concentration was measured
on July 4, 2010 (0.188 ng/m3), but is significantly less than the maximum
concentrations measured in 2006 and 2008. While only 15 concentrations greater than
0.1 ng/m3 have been measured at S4MO since the onset of sampling, at least one has
been measured each year, with the exception of 2009.
After an initial increase from 2005 to 2006, the average and median concentrations
exhibit a decreasing trend, with nearly all of the statistical parameters reaching a
minimum in 2009. The average concentration increased from 2009 to 2010 and held
steady for 2011.
With the exception of 2011, both the minimum concentration and 5th percentile for
each year are zero, indicating the presence of non-detects (at least 5 percent). The
percentage of non-detects has ranged from less than 2 percent (2011) to 43 percent
(2009).
Observations from Figure 16-22 for lead include the following:
The maximum lead concentration was measured at S4MO in 2008 and was nearly
100 ng/m3. The second highest concentration was also measured in 2008 (84.8 ng/m3)
although a similar concentration was also measured in 2009.
Concentrations of lead measured at S4MO exhibit a relatively high level of
variability, as illustrated by the minimum and maximum concentrations. The
difference between these two statistical metrics has ranged from 30 ng/m3 (2011) to
96 ng/m3 (2008).
The average concentration of lead at S4MO has fluctuated over the years and exhibits
no real trend. The averages have ranged from 9.95 ng/m3 (2009) to 14.5 ng/m3
(2006). The confidence intervals calculated for these averages are relatively large and
therefore support the previous bullet. This site has had the highest annual average
concentration of lead for the last several years compared to other NMP sites sampling
metals under the NMP.
16-31
-------
The minimum concentration measured for each year is greater than zero, indicating
that there were no non-detects of lead reported for the years shown.
Observations from Figure 16-23 for manganese include the following:
The maximum manganese concentration was measured on November 26, 2008
(734 ng/m3) and is nearly twice the next highest concentration (395 ng/m3, measured
in 2011). A similar concentration was also measured in 2004 (387 ng/m3).
Four manganese concentrations greater than 100 ng/m3 have been measured at S4MO
since 2004, each in a different year. For each of these years, the second highest
concentration of manganese was an order of magnitude lower. For example, for 2011,
the two maximum concentrations are 395 ng/m3 and 65.3 ng/m3.
The average concentration of manganese has ranged from 12.5 ng/m3 (2007) to
21.9 ng/m3 (2008). The median concentration, which is influenced less by outliers,
has varied less, ranging from 6.82 ng/m3 (2009) to 11.6 ng/m3 (2006). The median
concentration actually has a decreasing trend from 2006 to 2009, despite the outlier
measured in 2008.
The minimum concentration measured for each year is greater than zero, indicating
that there were no non-detects of manganese reported for the years shown.
16.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
S4MO monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations regarding
the various toxicity factors, time frames, and calculations associated with these risk-based
screenings.
16.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Missouri monitoring site to the ATSDRMRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
16-32
-------
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
16.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for S4MO and where annual average concentrations could
be calculated, risk was examined by calculating cancer risk and noncancer hazard
approximations. These approximations can be used as risk estimates for cancer and noncancer
effects attributable to the pollutants of interest. Although the use of these approximations is
limited, they may help identify where policy-makers may want to shift or confirm their air-
monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer risk and
noncancer hazard approximations are calculated and what limitations are associated with them.
Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer hazard
approximations are presented in Table 16-6, where applicable. Cancer risk approximations are
presented as probabilities while the noncancer hazard approximations are ratios and thus, unitless
values.
Table 16-6. Risk Approximations for the Missouri Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
St. Louis, Missouri - S4MO
Acenaphthene3
Acetaldehyde
Arsenic (PM10)a
Benzene
Benzo(a)pyrenea
Beryllium (PM10)a
1,3 -Butadiene
Cadmium (PM10)a
0.000088
0.0000022
0.0043
0.0000078
0.00176
0.0024
0.00003
0.0018
0.009
0.000015
0.03
_
0.00002
0.002
0.00001
61/61
59/59
59/59
57/57
59/61
59/59
52/57
59/59
0.01
ฑ<0.01
2.75
ฑ0.43
<0.01
ฑ<0.01
0.80
ฑ0.06
<0.01
ฑ0.01
<0.01
ฑ<0.01
0.08
ฑ0.01
<0.01
ฑ<0.01
0.48
6.05
3.76
6.23
0.23
0.02
2.54
1.00
0.31
0.06
0.03
_
<0.01
0.04
0.06
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 16-5.
16-33
-------
Table 16-6. Risk Approximations for the Missouri Monitoring Site (Continued)
Pollutant
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Fluorene3
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Hexavalent Chromium3
Lead (PM10)a
Manganese (PM10)a
Naphthalene3
Nickel (PM10)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Cancer
URE
(Hg/m3)1
0.000006
0.000011
0.000026
0.0000025
0.000088
0.000013
0.000022
0.012
0.000034
0.00048
0.00000026
0.0000048
0.0000088
Noncancer
RfC
(mg/m3)
0.1
0.098
0.8
2.4
1
0.0098
0.09
0.0001
0.00015
0.00005
0.003
0.00009
0.04
0.002
0.1
#of
Measured
Detections
vs. # of
Samples
57/57
44/57
47/57
18/57
57/57
61/61
59/59
11/57
60/61
59/59
59/59
61/61
59/59
55/57
25/57
8/57
Annual
Average
(Hg/m3)
0.61
ฑ0.04
0.35
ฑ0.40
0.21
ฑ0.11
0.03
ฑ0.01
0.38
ฑ0.04
0.01
ฑ<0.01
4.25
ฑ0.92
0.02
ฑ0.01
0.01
ฑ0.01
0.01
ฑO.01
0.02
ฑ0.01
0.08
ฑ0.01
0.01
ฑ0.01
0.18
ฑ0.04
0.03
ฑ0.01
O.01
ฑO.01
Cancer Risk
Approximation
(in-a-million)
3.68
2.35
0.84
0.94
0.53
55.21
0.50
0.40
2.85
0.58
0.05
0.17
0.03
Noncancer
Hazard
Approximation
(HQ)
0.01
0.01
O.01
0.01
O.01
0.43
O.01
0.01
0.07
0.37
0.03
0.01
O.01
0.02
O.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 16-5.
Observations for S4MO from Table 16-6 include the following:
The pollutants with the highest annual average concentrations for S4MO are
formaldehyde, acetaldehyde, and benzene.
Formaldehyde, benzene, and acetaldehyde have the highest cancer risk
approximations for S4MO. The cancer risk approximation for formaldehyde
(55.21 in-a-million) is nearly nine times higher than the cancer risk approximations
for benzene and acetaldehyde, which were both approximately 6 in-a-million.
S4MO's cancer risk approximation for formaldehyde is the second highest cancer risk
approximation calculated among the site-specific pollutants of interest across the
program.
16-34
-------
Naphthalene has the highest cancer risk approximation among the PAHs
(2.58 in-a-million) and arsenic has the highest cancer risk approximation among the
metals (3.76 in-a-million).
None of the pollutants of interest for S4MO have noncancer hazard approximations
greater than 1.0, indicating that no adverse health effects are expected from these
individual pollutants. The pollutant with the highest noncancer hazard approximation
is formaldehyde (0.43), which is the fourth highest noncancer hazard approximation
calculated for a site-specific pollutant interest among NMP sites.
16.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 16-7 and 16-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 16-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 16-6. Table 16-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations, also calculated from annual averages provided in
Table 16-6.
The pollutants listed in Tables 16-7 and 16-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on the site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 16.3, S4MO sampled for VOCs, PAHs, carbonyl compounds, metals (PMi0), and
hexavalent chromium. In addition, the cancer risk and noncancer hazard approximations are
limited to those pollutants with enough data to meet the criteria for annual averages to be
calculated. A more in-depth discussion of this analysis is provided in Section 3.5.5.3. Similar to
the cancer risk and noncancer hazard approximations, this analysis may help policy-makers
prioritize their air monitoring activities.
16-35
-------
Table 16-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Missouri Monitoring Site
Oi
OJ
Oi
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
St. Louis, Missouri (St. Louis City) - S4MO
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Trichloroethylene
Naphthalene
Dichloromethane
POM, Group 2b
Methyl tert butyl ether
148.92
118.03
78.65
74.93
20.98
15.79
13.16
7.23
2.53
0.86
Hexavalent Chromium, PM
Formaldehyde
Arsenic, PM
Benzene
1,3 -Butadiene
Naphthalene
Nickel, PM
POM, Group 3
POM, Group 2b
Ethylbenzene
2.11E-03
1.53E-03
1.49E-03
1.16E-03
6.29E-04
4.47E-04
3.92E-04
3.24E-04
2.22E-04
1.97E-04
Formaldehyde
Benzene
Acetaldehyde
Arsenic
Carbon Tetrachloride
Naphthalene
1,3 -Butadiene
ฃ>-Dichlorobenzene
Cadmium
Ethylbenzene
55.21
6.23
6.05
3.76
3.68
2.85
2.54
2.35
1.00
0.94
-------
Table 16-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Missouri Monitoring Site
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
St. Louis, Missouri (St. Louis City) - S4MO
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Hexane
Hydrochloric acid
Ethylbenzene
Acetaldehyde
Methyl isobutyl ketone
522.43
358.32
289.83
148.92
118.03
116.82
109.87
78.65
74.93
73.11
Acrolein
Manganese, PM
Arsenic, PM
Formaldehyde
1,3 -Butadiene
Chlorine
Nickel, PM
Acetaldehyde
Trichloroethylene
Lead, PM
316,721.93
34,593.25
23,029.98
12,043.75
10,489.20
9,452.80
9,073.56
8,325.31
7,895.27
6,587.56
Formaldehyde
Manganese
Acetaldehyde
Lead
Arsenic
Cadmium
1,3 -Butadiene
Naphthalene
Benzene
Trichloroethylene
0.43
0.37
0.31
0.07
0.06
0.06
0.04
0.03
0.03
0.02
-------
Observations from Table 16-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in the city of St. Louis.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
cancer UREs) are hexavalent chromium, formaldehyde, and arsenic.
Six of the highest emitted pollutants also have the highest toxi city-weighted
emissions.
Five of the pollutants with the highest cancer risk approximations for S4MO also
appear on both emissions-based lists (formaldehyde, benzene, 1,3-butadiene,
ethylbenzene, and naphthalene). Other pollutants with the highest cancer risk
approximations for S4MO appear on one emissions-based list but not the other. While
arsenic is not one of the highest emitted pollutants, it ranks third for its toxi city-
weighted emissions. While acetaldehyde does not appear on the list of highest
toxicity-weighted emissions, it is the fourth highest emitted pollutant in the city of
St. Louis.
POM, Group 2b is the ninth highest emitted "pollutant" in St. Louis and ranks ninth
for toxicity-weighted emissions. POM, Group 2b includes several PAHs sampled for
at S4MO including acenaphthene and fluorene, which are pollutants of interest for
S4MO. These pollutants are not among those with the highest cancer risk
approximations for S4MO.
Observations from Table 16-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in the city of St. Louis.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, manganese, and arsenic. Although acrolein was
sampled for at S4MO, this pollutant was excluded from the pollutants of interest
designation, and thus subsequent risk-based screening evaluations, due to questions
about the consistency and reliability of the measurements, as discussed in Section 3.2.
Only two of the highest emitted pollutants in the city of St. Louis also have the
highest toxicity-weighted emissions (formaldehyde and acetaldehyde).
Formaldehyde and acetaldehyde are the pollutants with the highest and third highest
noncancer hazard approximations for S4MO, respectively, and are the only two
pollutants of interest to appear on both emissions-based lists. Manganese, the
pollutant with the second highest noncancer hazard approximation, is the pollutant
with the second highest toxicity-weighted emissions but is not one of the highest
emitted.
16-38
-------
16.6 Summary of the 2011 Monitoring Data for S4MO
Results from several of the data treatments described in this section include the
following:
ปซป Twenty-five pollutants, of which 13 are NA TTS MQO Core Analytes, failed screens
for S4MO.
ปซป Formaldehyde and acetaldehyde have the highest annual average concentrations for
S4MO. These are the only pollutants of interest with annual averages greater than
1 jug/m3.
ปซป S4MO had the highest annual average concentrations ofhexachloro-1,3-butadiene,
arsenic, cadmium, and lead among all NMP sites sampling these pollutants. S4MO
had the second highest annual average concentrations of 1,2-dichloroethane,
p-dichlorobenzene, formaldehyde, and manganese among all NMP sites sampling
these pollutants.
ปซป The trends analysis shows that concentrations of benzene have been decreasing at
S4MO, particularly the earlier years of sampling.
16-39
-------
17.0 Sites in New Jersey
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at UATMP and CSATAM sites in New Jersey, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
17.1 Site Characterization
This section characterizes the New Jersey monitoring sites by providing geographical and
physical information about the location of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring data.
The New Jersey sites are all located within the New York-Northern New Jersey-Long
Island, NY-NJ-PA MSA, although within different divisions. Figure 17-1 is a composite satellite
image retrieved from ArcGIS Explorer showing the CFINJ monitoring site in its urban location.
Figure 17-2 identifies nearby point source emissions locations by source category, as reported in
the 2008 NEI for point sources. Figures 17-3 through 17-7 are the composite satellite maps and
emissions source maps for the remaining New Jersey monitoring sites. Note that only sources
within 10 miles of the sites are included in the facility counts provided in Figures 17-2, 17-5, and
17-7. A 10-mile boundary was chosen to give the reader an indication of which emissions
sources and emissions source categories could potentially have a direct effect on the air quality at
the monitoring sites. Further, this boundary provides both the proximity of emissions sources to
the monitoring sites as well as the quantity of such sources within a given distance of the sites.
Sources outside the 10-mile radii are still visible on the maps, but have been grayed out in order
to show emissions sources just outside the boundary. Table 17-1 provides supplemental
geographical information such as land use, location setting, and locational coordinates.
17-1
-------
Figure 17-1. Chester, New Jersey (CHNJ) Monitoring Site
to
-------
Figure 17-2. NEI Point Sources Located Within 10 Miles of CHNJ
74'50'Q"W 74'45trW 7JU40B"W 74'35'CTW
Mole: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
Legend
@ CHNJ UATMP site 10 mile radius | | County boundary
Source Category Group (No. of Facilities) F Food Processing/Agriculture (1)
-f Aircraft Operations (12) (B Hospital (1)
i Asphalt Processing/Roofing Manufacturing (1) .-; Mine/Quarry (1)
o Clay Ceramics Manufacturing (3) M Miscellaneous Manufacturing (2)
Concrete Batch Plant (1) <=> Pharmaceutical Manufacturing (1)
ฉ Fabricated Metal Products (1) H Pulp and Paper Plant/Wood Products (2)
17-3
-------
Figure 17-3. Elizabeth, New Jersey (ELNJ) Monitoring Site
-------
Figure 17-4. New Brunswick, New Jersey (NBNJ) Monitoring Site
-------
Figure 17-5. NEI Point Sources Located Within 10 Miles of ELNJ and NBNJ
7445-0-W 7440TO-W 7< 35TrW 74 3ffO"W 74'25'0-W 7a'20'0-W 74-151TW 74'M'ITW 74 SKTW
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
ELNJ UATMP site
NBNJ UATMP site
10 mile radius I County boundary
Source Category Group (No. of Facilities)
^ Aircraft Operations (44)
I Asphalt Pfocessing/Roofirm Manufacturing (3)
Q Auto Body ShoprPanters (1)
ft Bakery (2)
Y Brewery/Distillery Winery (1)
f BuiklirtQ Construction (\)
B Bulk Terminate/Bulk Plants < 13)
C Chemical Msnufaclunng (24}
O Clay Ceramics Manufacturing <3t
ฃ Electricity Generation via Combustion (21)
E Elec&oplalmg, Plating. Polishing. Anodizing, and Coloring <2)
<> Fabricated Metal Products (12)
Ci> R&xibte Potyurcthane Foam Production (2)
F Food ProcessmoyAgncullurelS)
[~j Furniture Plant (2)
Gasoline/Diesel Service Station {1>
Gypsum Manufacturing |1 )
Heating Equipment Manufacturing ^ 1 >
Hot Mix Asphalt Plant (2)
indusErtat Machinery and Equipment (S)
insbliiiionai - school (14)
Laboratory (1)
Landfill (?)
Lumbertsawmilio}
Marine Port (1)
iWarine Vessel Loading Rack (1)
Mine/Quarry (1)
Miscellaneous Commercial/Industrial (24)
Miscellaneous Man ufactu n nri { 1 3)
Municipal Wisle Combustor (2)
Oil and/of Gas Production {1)
A Petrateum Refinery (3)
._ Pharmaceutical Manufacturing (7)
1 Pnmary Metal Production (1)
^ Printing. Coattng fi Dyeing of Fabrics (t)
P Pnnting/Publi&riing (10)
(H Pulp and Paper PlantMtood Products (13)
R Rubber and Miscellaneous Plastics Products (12J
2 Secondary Metal Processing (1)
> Solid Waste Disposal - Commercial/institutional (4)
V Steel Mm (2)
S Surface Coating (16)
ฉ Tire Manufacture (1)
^ Transportation and Marketing of Petroleum Products (2)
I Wastewaler Treatment {Bt
W Woodwork. Furniture. Millwork & Wood Preserving (2)
17-6
-------
Figure 17-6. Paterson, New Jersey (PANJ) Monitoring Site
-------
Figure 17-7. NEI Point Sources Located Within 10 Miles of PANJ
Legend
74--1 STO'W 74' 10'0"W 74" 5'0"W 74'0'0'W
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
PANJ CSATAM site
10 mile radius
County boundary
Source Category Group (No. of Facilities) ?
4< Aircraft Operations (21) M
B Bakery (1)
B Bulk Terminals/Bulk Plants (1)
C Chemical Manufacturing (8) 1
O Clay Ceramics Manufacturing (1) -t
6 Electrical Equipment (4) P
f Electricity Generation via Combustion (4) ffi
E Electroplating. Plating. Polishing, Anodizing, & Coloring (i) R
ฉ Fabricated Metal Products <3) <
^ Flexible Polyurethane Foam Production (3) V
F Food Processing/Agriculture (3) S
GJ Hospital (3) T
$ Hot Mix Asphalt Plant (3)
$ industrial Machinery and Equipment (2) '
^ Institutional - school (2) W
Miscellaneous CornmerciaVlrtdustrial (3)
Miscellaneous Manufacturing (20)
Oil and/or Gas Production (1)
Pharmaceutical Manufacturing {4)
Primary Metal Production (3)
Printing, Coaling & Dyeing of Fabric f 1)
Prinling/Publishirtg (t3)
Pulp and Pa pe r PlanLWood Products (10)
Rubber and Miscellaneous Plastics Products (4)
Site Remediation Activity (1)
Steel Mill {1)
Surface Coating (S}
Textile Mill (4)
Transportation Equipment (1)
Wastewater Treatment (1)
Woodwork, Furniture, MiHwork & Wood Preserving (1J
17-8
-------
Table 17-1. Geographical Information for the New Jersey Monitoring Sites
Site
Code
CHNJ
ELNJ
NBNJ
PANJ
AQS Code
34-027-3001
34-039-0004
34-023-0006
34-031-0005
Location
Chester
Elizabeth
New
Brunswick
Paterson
County
Morris
Union
Middlesex
Passaic
Micro- or Metropolitan
Statistical Area
New York-Northern
New Jersey -Long Island,
NY-NJ-PAMSA
(Newark Div)
New York-Northern
New Jersey -Long Island,
NY-NJ-PAMSA
(Newark Div)
New York-Northern
New Jersey -Long Island,
NY-NJ-PA MSA
(Edison Div)
New York-Northern
New Jersey -Long Island,
NY-NJ-PAMSA
(New York Div)
Latitude
and
Longitude
40.78763,
-74.6763
40.64144,
-74.20836
40.472786,
-74.42251
40.918381,
-74.168092
Land Use
Agricultural
Industrial
Agricultural
Commercial
Location
Setting
Rural
Suburban
Rural
Urban/City
Center
Additional Ambient Monitoring
Information1
SO2, NO, NO2, O3, Meteorological
parameters, PM2 5, PM2.5 Speciation
CO, SO2, NO2, NOX, Meteorological
parameters, PM2 5, PM2 5 Speciation
Meteorological parameters, PM2 5, PM2 5
Speciation
Meteorological Parameters, PM2 5
:Data for additional pollutants are reported to AQS for these sites (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this
report.
-------
CHNJ is located in northern New Jersey, in the town of Chester, west of the New York
City metropolitan area. Figure 17-1 shows that CHNJ is located in an open area near Building 1
on the property of Bell Labs, which is owned by Alcatel-Lucent. The surrounding area is rural
and agricultural with a rolling topography, but surrounded by small neighborhoods. Although the
location is considered part of the New York City MSA, the site's location is outside most of the
urbanized areas. Figure 17-2 shows that few sources are close to CFINJ and that the source
category with the greatest number of emissions sources surrounding CFINJ is the aircraft
operations category, which includes airports as well as small runways, heliports, or landing pads.
The source closest to CFINJ is in the pulp and paper/wood products source category.
ELNJ is located in the city of Elizabeth, which lies just south of Newark and west of
Newark Bay and Staten Island, New York. As Figure 17-3 shows, the monitoring site is located
just off Exit 13 of the New Jersey Turnpike (1-95), near the toll plaza. Interstate-278 intersects
the Turnpike here as well. The surrounding area is highly industrialized, with an oil refinery
located just southwest of the site. Additional industry is located to the southwest, west, and east,
while residential neighborhoods are located to the northwest and north of the site.
NBNJ is located in New Brunswick, less than 20 miles southwest of Elizabeth. The
monitoring site is located on the property of Rutgers University's Cook-Douglass campus, on a
horticultural farm. The surrounding area is agricultural and rural, although residential
neighborhoods are located to the east, across a branch of the Raritan River, as shown in
Figure 17-4. County Road 617 (Ryders Lane) and US-1 intersect just west of the site and 1-95
runs northeast-southwest about 1 mile east of the site, part of which can be seen in the lower
right hand corner of Figure 17-4.
Figure 17-5 shows that the outer portions of the 10-mile radii for ELNJ and NBNJ
intersect and that many emissions sources surround these two sites. The bulk of the emissions
sources are located in northern Middlesex County and northeastward toward New York City and
northern New Jersey. The source categories with the greatest number of emissions sources in the
vicinity of these sites include aircraft operations, chemical manufacturing, electricity generation
via combustion, and surface coating. The emissions sources in closest proximity to the ELNJ
monitoring site are in the miscellaneous manufacturing, wastewater treatment, chemical
manufacturing, electricity generation via combustion, and petroleum refining categories. The
17-10
-------
emissions sources in closest proximity to the NBNJ monitoring site are involved in aircraft
operations and pharmaceutical manufacturing.
PANJ is located in northern New Jersey, in the town of Paterson, north of Newark and
between Clifton and Hackensack. The monitoring site is located at the local health department
with residential areas to the east and commercial areas to the west, as shown in Figure 17-6. The
Passaic River runs northeast-southwest just north of PANJ and is shown in the upper left corner
of Figure 17-6. Interstate-80 runs east-west less than 1 mile south of PANJ. Figure 17-7 shows
that the majority of point sources within 10 miles of PANJ are located to the southeast of the site.
Many of the point sources near PANJ are involved in aircraft operations, printing and publishing,
or pulp and paper products, although the source closest to PANJ falls in the miscellaneous
industries category.
Table 17-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the New Jersey monitoring sites. Table 17-2 includes a county-level
population for each site. County-level vehicle registration data for Union, Morris, Passaic, and
Middlesex Counties were not available from the State of New Jersey. Thus, state-level vehicle
registration, which was obtained from the Federal Highway Administration, was allocated to the
county level using the county-level proportion of the state population from the U.S. Census
Bureau. Table 17-2 also includes a county-level vehicle registration-to-population ratio, which
was calculated to represent the number of vehicles per person within each monitoring site's
residing county. In addition, the population within 10 miles of each site is presented, based on
postal code population data estimates. An estimate of 10-mile vehicle ownership was then
determined by applying the county-level vehicle registration-to-population ratio to the 10-mile
population surrounding each monitoring site. Table 17-2 also contains traffic volume information
for each site. Finally, Table 17-2 presents the county-level daily VMT for Middlesex, Morris,
Passaic, and Union Counties.
17-11
-------
Table 17-2. Population, Motor Vehicle, and Traffic Information for the New Jersey
Monitoring Sites
Site
CHNJ
ELNJ
NBNJ
PANJ
Estimated
County
Population1
494,976
539,494
814,217
502,007
County-level
Vehicle
Registration2
389,359
424,894
640,893
396,602
Vehicles per
Person
(Registration:
Population)
0.79
0.79
0.79
0.79
Population
within 10
miles3
237,740
2,189,758
810,434
1,356,675
Estimated
10-mile
Vehicle
Ownership
187,012
1,724,607
637,915
1,071,818
Annual
Average
Daily
Traffic4
12,917
250,000
114,322
22,272
County-
level Daily
VMT5
14,256,044
12,485,902
20,415,685
8,178,167
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects ratios based on 2010 state-level vehicle registration data from the FHWA
and the 2010 county-level proportion of the state population data (FHWA, 2011 and Census Bureau, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT for ELNJ reflects 2006 data from NJ Department of Treasury and 2010 data from the New Jersey DOT for
the other sites (Steer, 2008 and NJ DOT, 2010a)
5County-level VMT reflects 2010 data from the New Jersey DOT (NJ DOT, 2010b)
Observations from Table 17-2 include the following:
Middlesex County, where NBNJ is located, has the highest county-level population of
the New Jersey sites while Morris County, where CHNJ is located, has the least.
ELNJ has the highest 10-mile population among the four New Jersey sites while
CHNJ has the least. The 10-mile populations for both ELNJ and PANJ are greater
than 1 million people.
Compared to NMP monitoring sites in other locations, the county-level populations
are in the middle of the range. However, ELNJ has one of the highest 10-mile
populations, ranking third among NMP sites. The 10-mile populations for the other
New Jersey sites range from eight highest (PANJ) to 36th highest (CHNJ).
The estimated county-level vehicle registration is highest for NBNJ while the vehicle
ownerships across the remaining New Jersey sites are fairly similar to each other. The
county-level registration estimates for all the sites are in the middle of the range
compared to other NMP sites. ELNJ and PANJ have the highest 10-mile vehicle
ownership estimates compared to the other New Jersey sites and rank second and
sixth compared to other NMP sites.
ELNJ and NBNJ experience a significantly higher average traffic volume than CHNJ
and PANJ. Traffic data for ELNJ are provided for 1-95, between Exit 13 and 13 A;
this is the highest traffic volume among all NMP sites. Traffic data for CHNJ are
provided for Main Street (County Road 513) near Highway 206 in downtown
Chester; traffic data for NBNJ are provided for US-1 near State Road 617 (Ryders
Lane); and traffic data for PANJ are provided for Memorial Drive between Ellison
Street and College Boulevard.
17-12
-------
Among the New Jersey counties with monitoring sites, VMT for Middlesex County is
highest while VMT for Passaic County is the lowest. However, county-level VMT for
the New Jersey counties are in the middle of the range compared to other counties
with NMP sites (where VMT data were available).
17.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in New Jersey on sample days, as well as over the course of the year.
17.2.1 Climate Summary
Frontal systems push across the state of New Jersey regularly, producing variable
weather conditions. The state's proximity to the Atlantic Ocean has a moderating effect on
temperature. Summers along the coast tend to be cooler than areas farther inland, while winters
tend to be warmer. Large urban areas within the state experience the urban heat island effect, in
which urban areas retain more heat than outlying areas. New Jersey's mid-Atlantic location also
allows for ample annual precipitation and relatively high humidity. A southwesterly wind is most
common in the summer and a northwesterly wind is typical in the winter. Winds from the west
and northwest result in air masses that dry out, stabilize, and warm as they move eastward from
higher elevations to sea level (Bair, 1992 and Rutgers, 2013).
17.2.2 Meteorological Conditions in 2011
Hourly meteorological data from NWS weather stations nearest these sites were retrieved
for 2011 (NCDC, 2011). The three closest weather stations are located at Somerville-Somerset
Airport (near CHNJ and NBNJ), Newark International Airport (near ELNJ), and Essex County
Airport (near PANJ), WBAN 54785, 14734, and 54743, respectively. Additional information
about these weather stations, such as the distance between the sites and the weather stations, is
provided in Table 17-3. These data were used to determine how meteorological conditions on
sample days vary from conditions experienced throughout the year.
17-13
-------
Table 17-3. Average Meteorological Conditions near the New Jersey Monitoring Sites
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Chester, New Jersey - CHNJ
Somerville, New
Jersey/Somerset
Airport
54785
(40.62, -74.67)
11.30
miles
165ฐ
(SSE)
Sample
Day
2011
63.3
ฑ4.6
63.8
ฑ1.9
53.2
ฑ4.3
53.3
ฑ1.8
42.2
ฑ4.7
43.0
ฑ2.0
48.0
ฑ4.1
48.4
ฑ1.7
69.8
ฑ3.5
71.7
ฑ1.3
1015.8
ฑ1.8
1015.4
ฑ0.8
3.4
ฑ0.6
2.9
ฑ0.2
Elizabeth, New Jersey - ELNJ
Newark International
Airport
14734
(40.68, -74.17)
3.45
miles
20ฐ
(NNE)
Sample
Day
2011
64.3
ฑ4.6
65.2
ฑ 1.9
56.6
ฑ4.3
57.4
ฑ1.8
41.9
ฑ4.7
42.9
ฑ 1.9
49.6
ฑ3.9
50.3
ฑ1.6
61.0
ฑ3.8
61.6
ฑ 1.5
1015.8
ฑ1.9
1015.6
ฑ0.8
8.0
ฑ0.9
7.6
ฑ0.3
New Brunswick, New Jersey - NBNJ
Somerville, New
Jersey/Somerset
Airport
54785
(40.62, -74.67)
16.06
miles
297ฐ
(WNW)
Sample
Day
2011
63.0
ฑ4.3
63.8
ฑ1.9
53.1
ฑ4.1
53.3
ฑ1.8
42.4
ฑ4.5
43.0
ฑ2.0
48.1
ฑ3.9
48.4
ฑ1.7
70.7
ฑ3.4
71.7
ฑ1.3
1015.6
ฑ 1.8
1015.4
ฑ0.8
3.4
ฑ0.6
2.9
ฑ0.2
Paterson, New Jersey - PANJ
Essex County
Airport
54743
(40.88, -74.28)
6.39
miles
229ฐ
(SW)
Sample
Day
2011
48.1
ฑ8.2
62.9
ฑ1.9
39.8
ฑ7.8
53.9
ฑ 1.8
26.3
ฑ8.2
42.8
ฑ2.0
34.7
ฑ7.2
48.6
ฑ 1.7
61.7
ฑ8.2
69.5
ฑ1.5
1017.5
ฑ5.7
1016.3
ฑ0.8
5.1
ฑ 1.3
3.5
ฑ0.2
1 Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Table 17-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 17-3 is the
95 percent confidence interval for each parameter. As shown in Table 17-3, average
meteorological conditions on sample days were representative of average weather conditions
throughout the year for CHNJ, ELNJ, and NBNJ. It appears that sample days at PANJ were
cooler, drier, and windier than for the entire year as a whole. However, a 1-year monitoring
effort at PANJ was completed in May 2011, thereby missing the warmer months of the year.
17.2.3 Back Trajectory Analysis
Figure 17-8 is the composite back trajectory map for days on which samples were
collected at the CHNJ monitoring site in 2011. Included in Figure 17-8 are four back trajectories
per sample day. Figure 17-9 is the corresponding cluster analysis. Similarly, Figures 17-10
through 17-13 are the composite back trajectory maps and corresponding cluster analyses for
ELNJ and NBNJ. Figure 17-14 is the composite back trajectory map for PANJ but a cluster
analysis was not performed for this site because there were fewer than 30 sample days. An in-
depth description of these maps and how they were generated is presented in Section 3.5.2.1. For
the composite maps, each line represents the 24-hour trajectory along which a parcel of air
traveled toward the monitoring site on a given sample day and time, based on an initial height of
50 meters AGL. For the cluster analyses, each line corresponds to a trajectory representative of a
given cluster of back trajectories. Each concentric circle around the sites in Figures 17-8 through
17-14 represents 100 miles.
17-15
-------
Figure 17-8. 2011 Composite Back Trajectory Map for CHNJ
Figure 17-9. Back Trajectory Cluster Map for CHNJ
17-16
-------
Figure 17-10. 2011 Composite Back Trajectory Map for ELNJ
Figure 17-11. Back Trajectory Cluster Map for ELNJ
" \
17-17
-------
Figure 17-12. 2011 Composite Back Trajectory Map for NBNJ
Figure 17-13. Back Trajectory Cluster Map for NBNJ
17-18
-------
Figure 17-14. 2011 Composite Back Trajectory Map for PANJ
Observations from Figures 17-8 through 17-14 include the following:
Due to their relatively close proximity to each other and the standardization of sample
days, the back trajectories shown on each composite back trajectory map for the New
Jersey sites are similar to each other. The composite back trajectory map for PANJ
includes one-third of the back trajectories compared to the other sites as PANJ
stopped sampling in May 2011 and sampled on a l-in-12 day sachedule.
Back trajectories originated from a variety of directions at the sites. In general, the
longest back trajectories originated from northwest of the monitoring sites.
The 24-hour air shed domains for the New Jersey sites were similar in size to each
other. Back trajectories greater than 600 miles in length originated near Lake Superior
and Ontario, Canada. The average trajectory length for these sites ranged from
251 miles (CJTNJ) to 259 miles (NBNJ).
17-19
-------
The cluster trajectories for the New Jersey sites are similar to each other in
geographical distribution, although the percentages vary. Each of the cluster maps has
a relatively short cluster originating to the west of the sites over central Pennsylvania,
representing approximately 30 percent of back trajectories. This cluster trajectory
represents relatively short back trajectories (<250 miles) originating from a direction
with a westerly component. Another roughly 20 percent of back trajectories
originated from the west and northwest of the site but of longer length. For CHNJ and
ELNJ, these are split into two clusters, one from the west and one from the northwest.
Roughly 20 percent of back trajectories originated to the south, 20 percent to the east,
and 10 percent to the north.
17.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations nearest the New Jersey sites, as
presented in Section 17.2.2, were uploaded into a wind rose software program to produce
customized wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind
directions using "petals" positioned around a 16-point compass, and uses different colors to
represent wind speeds.
Figure 17-15 presents a map showing the distance between the NWS station and CFtNJ,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 17-15 also presents three different wind roses for the
CFINJ monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figures 17-16 through 17-18 present the distance maps and
wind roses for ELNJ, NBNJ, and PANJ, respectively.
17-20
-------
Figure 17-15. Wind Roses for the Summerville-Somerset Airport Weather Station near
CHNJ
Distance between CHNJ and NWS Station
2001-2010 Historical Wind Rose
NWS
Station
\ '+.
2011 Wind Rose
Sample Day Wind Rose
17-21
-------
Figure 17-16. Wind Roses for the Newark International Airport Weather Station near
ELNJ
Distance between ELNJ and NWS Station
2001-2010 Historical Wind Rose
-*' i
iff? '^"
1
~","J-
/VEST
2011 Wind Rose
Sample Day Wind Rose
17-22
-------
Figure 17-17. Wind Roses for the Summerville-Somerset Airport Weather Station near
NBNJ
Distance between NBNJ and NWS Station
2001-2010 Historical Wind Rose
JEAOINOTON ซ.ซ!ซป. B
' MANVJtftt ~>^_ ^
^Lg^^jpH*;'?^*""***
f*ซซ-ฃfc*^j T^v"' '^ Edi?o(
? EAST
g MILL* TOME o**'1 L* TOMI
2011 Wind Rose
Sample Day Wind Rose
17-23
-------
Figure 17-18. Wind Roses for the Essex County Airport Weather Station near PANJ
Distance between PANJ and NWS Station
2001-2010 Historical Wind Rose
N.
' ,-..-ป
T. - 7'
-a~ / 4
2011 Wind Rose
Sample Day Wind Rose
17-24
-------
Observations from Figures 17-15 and 17-17 for CHNJ and NBNJ include the following:
The NWS weather station at Somerville/Somerset Airport is the closest weather
station to both CHNJ and NBNJ. The Somerville/Somerset Airport weather station is
located approximately 11.3 miles south-southeast of CHNJ and 16.1 miles
west-northwest of NBNJ.
The wind data for the historical and full-year wind roses for CHNJ and NBNJ are
identical because they are from the same weather station.
The historical wind roses for these sites show that calm winds accounted for greater
than 40 percent of observations. For wind speeds greater than 2 knots, northerly
winds were observed most frequently, accounting for nearly 10 percent of the
observations, while winds from the southwest quadrant were rarely observed.
Calm winds account nearly 50 percent of the wind observations throughout 2011.
Winds from the northwest quadrant, including northerly winds, account for another
one-quarter of wind observations throughout 2011.
Wind patterns on sample day wind roses resemble the full-year wind patterns, with
even more wind observations from the northwest quadrant. The similarities in the
wind patterns indicate that conditions on sample days were similar to conditions
experienced near these sites over the course of 2011.
While the 2011 wind roses do exhibit the same prevalence for calm winds as the
historical wind rose, they do not exhibit the same northerly predominance for wind
speeds greater than 2 knots. Instead, there was an increase in winds from the
northwest quadrant. A similar observation was made for 2009 in the 2008-2009 NMP
report and in the 2010 NMP report.
Observations from Figure 17-16 for ELNJ include the following:
The Newark International Airport weather station is located approximately 3.5 miles
north-northeast of ELNJ.
The historical wind rose shows that winds from a variety of directions were observed
near ELNJ, although easterly winds and winds from the southeast quadrant were
observed infrequently. Calm winds were observed for less than six percent of
observations. The strongest winds were associated with westerly and northwesterly
winds.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, although there are some differences. For instance, the calm rate for 2011 is
higher than the historical calm rate. Westerly and west-southwesterly winds were
slightly less prominent in 2011 compared to historical observations.
17-25
-------
The sample day wind rose has a similar calm rate as the 2011 full-year wind rose, but
there are a number of differences as well. Winds from the southwest quadrant were
observed less while winds from the west-northwest and northwest were observed
more frequently on sample days.
Observations from Figure 17-18 for PANJ include the following:
The Essex County Airport weather station is located approximately 6.4 miles
southwest of PANJ.
The historical wind rose shows that calm winds account for approximately one-third
of the wind observations near PANJ. Winds from the western quadrants account for
the majority of winds greater than 2 knots, particularly winds from the west-
northwest and northwest. The strongest winds were associated with westerly to
northwesterly winds.
The 2011 wind rose shows that calm winds accounted for greater than 40 percent of
wind observations in 2011 and that west-northwesterly to north-northwesterly winds
account for the majority of wind observations greater than 2 knots. This represents a
northward shift in the predominant wind direction compared to the historical wind
rose.
The sample day wind rose for PANJ exhibits several differences from the historical
and full-year wind roses. The sample day wind rose has a lower percentage of calm
winds. The percentage of northwesterly wind observations is double that shown in the
full-year wind rose. There is also a higher percentage of winds from the east-northeast
and fewer from the southwest quadrant. This wind rose likely reflects a seasonal
pattern as it only includes sample days through May 2011 to correspond with the
sample period.
17.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the New Jersey monitoring sites
in order to allow analysts and readers to focus on a subset of pollutants through the context of
risk. For each site, each pollutant's preprocessed daily measurement was compared to its
associated risk screening value. If the concentration was greater than the risk screening value,
then the concentration "failed the screen." Pollutants of interest are those for which the
individual pollutant's total failed screens contribute to the top 95 percent of the site's total failed
screens. In addition, if any of the NATTS MQO Core Analytes measured by each monitoring site
did not meet the pollutant of interest criteria based on the preliminary risk-based screening, that
pollutant was added to the list of site-specific pollutants of interest. A more in-depth description
of the risk-based screening process is presented in Section 3.2.
17-26
-------
Table 17-4 presents the results of the preliminary risk-based screening process for the
New Jersey sites. The pollutants that failed at least one screen and contributed to 95 percent of
the total failed screens for each monitoring site are shaded. NATTS MQO Core Analytes are
bolded. Thus, pollutants of interest are shaded and/or bolded. All three UATMP sites sampled
for VOCs and carbonyl compounds while PANJ sampled for VOCs only.
Table 17-4. Risk-Based Screening Results for the New Jersey Monitoring Sites
Pollutant
Screening
Value
(Hg/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Chester, New Jersey - CHNJ
Acetaldehyde
Benzene
Carbon Tetrachloride
Formaldehyde
Acrylonitrile
1,3-Butadiene
1,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
ฃ>-Dichlorobenzene
1 , 1 ,2,2-Tetrachloroethane
Chloromethylbenzene
1 ,2-Dibromoethane
Dichloromethane
Ethylbenzene
1 , 1 ,2-Trichloroethane
Trichloroethylene
Xylenes
0.45
0.13
0.17
0.077
0.015
0.03
0.038
0.045
0.091
0.017
0.02
0.0017
7.7
0.4
0.0625
0.2
10
Total
61
61
61
61
35
24
19
6
5
5
1
1
1
1
1
1
1
345
61
61
61
61
35
31
19
6
25
5
1
1
61
61
1
5
61
556
100.00
100.00
100.00
100.00
100.00
77.42
100.00
100.00
20.00
100.00
100.00
100.00
1.64
1.64
100.00
20.00
1.64
62.05
17.68
17.68
17.68
17.68
10.14
6.96
5.51
1.74
1.45
1.45
0.29
0.29
0.29
0.29
0.29
0.29
0.29
17.68
35.36
53.04
70.72
80.87
87.83
93.33
95.07
96.52
97.97
98.26
98.55
98.84
99.13
99.42
99.71
100.00
Elizabeth, New Jersey - ELNJ
Acetaldehyde
Benzene
Formaldehyde
Carbon Tetrachloride
1,3-Butadiene
Ethylbenzene
ฃ>-Dichlorobenzene
1,2-Dichloroethane
Acrylonitrile
Propionaldehyde
Hexachloro- 1 ,3 -butadiene
1 ,2-Dibromoethane
Trichloroethylene
0.45
0.13
0.077
0.17
0.03
0.4
0.091
0.038
0.015
0.8
0.045
0.0017
0.2
61
61
61
60
59
29
27
16
11
9
4
3
2
61
61
61
61
59
61
49
16
11
61
6
3
24
100.00
100.00
100.00
98.36
100.00
47.54
55.10
100.00
100.00
14.75
66.67
100.00
8.33
15.02
15.02
15.02
14.78
14.53
7.14
6.65
3.94
2.71
2.22
0.99
0.74
0.49
15.02
30.05
45.07
59.85
74.38
81.53
88.18
92.12
94.83
97.04
98.03
98.77
99.26
17-27
-------
Table 17-4. Risk-Based Screening Results for the New Jersey Monitoring Sites (Continued)
Pollutant
Dichloromethane
1, 1,2,2-Tetrachloroethane
Xylenes
Screening
Value
(Ug/m3)
7.7
0.017
10
Total
#of
Failed
Screens
1
1
1
406
#of
Measured
Detections
61
1
61
657
%of
Screens
Failed
1.64
100.00
1.64
61.80
% of Total
Failures
0.25
0.25
0.25
Cumulative
%
Contribution
99.51
99.75
100.00
New Brunswick, New Jersey - NBNJ
Acetaldehyde
Formaldehyde
Benzene
Carbon Tetrachloride
1,3-Butadiene
Acrylonitrile
1 ,2-Dichloroethane
ฃ>-Dichlorobenzene
Hexachloro- 1 ,3 -butadiene
Ethylbenzene
1 , 1 ,2,2-Tetrachloroethane
1 ,2-Dibromoethane
Bromomethane
Chloromethylbenzene
Dichloromethane
Propionaldehyde
1 , 1 ,2-Trichloroethane
Xylenes
0.45
0.077
0.13
0.17
0.03
0.015
0.038
0.091
0.045
0.4
0.017
0.0017
0.5
0.02
7.7
0.8
0.0625
10
Total
62
62
58
57
39
25
19
15
8
7
4
2
1
1
1
1
1
1
364
62
62
58
58
42
25
19
39
9
58
4
2
37
1
58
62
1
58
655
100.00
100.00
100.00
98.28
92.86
100.00
100.00
38.46
88.89
12.07
100.00
100.00
2.70
100.00
1.72
1.61
100.00
1.72
55.57
17.03
17.03
15.93
15.66
10.71
6.87
5.22
4.12
2.20
1.92
1.10
0.55
0.27
0.27
0.27
0.27
0.27
0.27
17.03
34.07
50.00
65.66
76.37
83.24
88.46
92.58
94.78
96.70
97.80
98.35
98.63
98.90
99.18
99.45
99.73
100.00
Paterson, New Jersey - PANJ
Benzene
1,3-Butadiene
Carbon Tetrachloride
ฃ>-Dichlorobenzene
Ethylbenzene
1 ,2-Dibromoethane
Acrylonitrile
1 ,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
1 , 1 ,2,2-Tetrachloroethane
0.13
0.03
0.17
0.091
0.4
0.0017
0.015
0.038
0.045
0.017
Total
12
12
10
10
9
3
2
2
2
1
63
12
12
12
12
12
3
2
2
2
1
70
100.00
100.00
83.33
83.33
75.00
100.00
100.00
100.00
100.00
100.00
90.00
19.05
19.05
15.87
15.87
14.29
4.76
3.17
3.17
3.17
1.59
19.05
38.10
53.97
69.84
84.13
88.89
92.06
95.24
98.41
100.00
Observations from Table 17-4 include the following:
Seventeen pollutants failed at least one screen for CHNJ (including six NATTS MQO
Core Analytes); 16 failed screens for ELNJ (including six NATTS MQO Core
Analytes); 18 failed screens for NBNJ (including five NATTS MQO Core Analytes);
and 10 failed screens for PANJ (including three NATTS MQO Core Analytes).
17-28
-------
The risk-based screening process identified eight pollutants of interest for CHNJ (of
which five are NATTS MQO Core Analytes). Trichloroethylene was added as a
pollutant of interest because it is a NATTS MQO Core Analyte, even though it did
not contribute to 95 percent of failed screens. Chloroform, tetrachloroethylene, and
vinyl chloride were added as pollutants of interest because they are also NATTS
MQO Core Analytes, even though they did not fail any screens. These three
pollutants are not shown in Table 17-4 but are shown in subsequent tables in the
sections that follow.
The risk-based screening process identified 10 pollutants of interest for ELNJ (of
which five are NATTS MQO Core Analytes). Trichloroethylene was added as a
pollutant of interest because it is a NATTS MQO Core Analyte, even though it did
not contribute to 95 percent of failed screens. Chloroform, tetrachloroethylene, and
vinyl chloride were also added because they are NATTS MQO Core Analytes, even
though they did not fail any screens. These three pollutants are not shown in
Table 17-4 but are shown in subsequent tables in the sections that follow.
The risk-based screening process identified 10 pollutants of interest for NBNJ (of
which five are NATTS MQO Core Analytes). Chloroform, tetrachloroethylene,
trichloroethylene, and vinyl chloride were added as pollutants of interest because they
are also NATTS MQO Core Analytes, even though they did not fail any screens.
These four pollutants are not shown in Table 17-4 but are shown in subsequent tables
in the sections that follow.
The risk-based screening process identified nine pollutants of interest for PANJ (of
which three are NATTS MQO Core Analytes). Chloroform, tetrachloroethylene,
trichloroethylene, and vinyl chloride were added as pollutants of interest because they
are also NATTS MQO Core Analytes, even though they did not fail any screens.
These four pollutants are not shown in Table 17-4 but are shown in subsequent tables
in the sections that follow.
For CHNJ, many of the pollutants failed a single screen. This may indicate that the
concentrations on a single day may be the cause. A review of the data shows that
many of these failed screens were for the same sample day. The concentrations of
dichloromethane, ethylbenzene, trichloroethylene, and xylenes all failed the screen
for July 8, 2011. 1,2-Dibromoethane and 1,1,2-trichloroethane failed screen a single
for May 27, 2011.
The concentrations of dichloromethane, trichloroethylene, and xylenes all failed the
screen for July 8, 2011 for ELNJ, which is the same date as several of the pollutants
of interest for CHNJ. 1,2-Dibromoethane also failed the screen for May 27, 2011 for
ELNJ.
While there are no similarities in failed screens for NBNJ with CJrENJ or ELNJ, there
are some common sample days among the pollutants failing relatively few screens.
Chioromethylbenzene, 1,2-dibromoethane, and 1,1,2-trichloroethane each failed the
screen for November 2, 2011, as did 1,1,2,2-tetrachloroethane. Dichloromethane and
xylenes each failed the screen for April 9, 2011.
17-29
-------
Many of the pollutants listed for PANJ failed screens on February 20, 2011;
May 9, 2011; and May 15,2011.
17.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the New Jersey monitoring sites. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest for the New Jersey monitoring sites, where the data meet
the applicable criteria. Concentration averages for select pollutants are also presented graphically
for the sites to illustrate how the sites' concentrations compare to the program-level averages, as
presented in Section 4.1. In addition, concentration averages for select pollutants are presented
from previous years of sampling in order to characterize concentration trends at the sites.
Additional site-specific statistical summaries for the New Jersey sites are provided in
Appendices J and L.
17.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each New Jersey site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the New Jersey
monitoring sites are presented in Table 17-5, where applicable. Note that if a pollutant was not
detected in a given calendar quarter, the quarterly average simply reflects "0" because only zeros
substituted for non-detects were factored into the quarterly average concentration.
17-30
-------
Table 17-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the New Jersey Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Chester, New Jersey - CHNJ
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
61/61
35/61
61/61
31/61
61/61
50/61
19/61
61/61
6/61
40/61
5/61
5/61
1.15
ฑ0.21
0.08
ฑ0.03
0.60
ฑ0.08
0.02
ฑ0.01
0.55
ฑ0.04
0.08
ฑ0.01
0.01
ฑ0.01
0.75
ฑ0.14
0.02
ฑ0.02
0.08
ฑ0.01
0
0
1.82
ฑ0.49
0.12
ฑ0.05
0.44
ฑ0.09
0.01
ฑ0.01
0.62
ฑ0.07
0.11
ฑ0.03
0.03
ฑ0.03
2.87
ฑ1.48
0.02
ฑ0.03
0.10
ฑ0.06
0.01
ฑ0.01
<0.01
ฑ<0.01
1.72
ฑ0.43
0.19
ฑ0.17
0.50
ฑ0.22
0.03
ฑ0.03
0.68
ฑ0.08
0.13
ฑ0.11
0.05
ฑ0.07
4.16
ฑ1.73
0.01
ฑ0.01
0.12
ฑ0.13
0.17
ฑ0.34
<0.01
ฑ0.01
1.76
ฑ0.41
0.03
ฑ0.03
0.57
ฑ0.09
0.04
ฑ0.01
0.65
ฑ0.07
0.10
ฑ0.02
0.05
ฑ0.02
1.66
ฑ0.21
0
0.07
ฑ0.03
0.01
ฑ0.01
<0.01
ฑ<0.01
1.61
ฑ0.20
0.10
ฑ0.05
0.53
ฑ0.07
0.02
ฑ0.01
0.62
ฑ0.03
0.10
ฑ0.03
0.03
ฑ0.02
2.37
ฑ0.63
0.01
ฑ0.01
0.09
ฑ0.04
0.05
ฑ0.09
<0.01
ฑ<0.01
Elizabeth, New Jersey - ELNJ
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
61/61
11/61
61/61
59/61
61/61
48/61
49/61
16/61
61/61
61/61
2.15
ฑ0.40
0.01
ฑ0.02
0.92
ฑ0.14
0.11
ฑ0.03
0.50
ฑ0.04
0.08
ฑ0.02
0.06
ฑ0.02
0.01
ฑ0.02
0.30
ฑ0.06
2.06
ฑ0.46
3.44
ฑ0.85
0.10
ฑ0.06
0.91
ฑ0.20
0.12
ฑ0.03
0.62
ฑ0.06
0.18
ฑ0.06
0.15
ฑ0.08
0.03
ฑ0.03
0.46
ฑ0.13
3.63
ฑ 1.06
4.11
ฑ0.78
0
1.18
ฑ0.41
0.14
ฑ0.03
0.67
ฑ0.04
0.18
ฑ0.09
0.11
ฑ0.05
0.03
ฑ0.04
0.82
ฑ0.62
4.70
ฑ0.91
3.28
ฑ0.85
0.04
ฑ0.08
1.09
ฑ0.28
0.17
ฑ0.04
0.66
ฑ0.10
0.12
ฑ0.04
0.08
ฑ0.03
0.04
ฑ0.03
0.45
ฑ0.12
3.41
ฑ0.62
3.24
ฑ0.39
0.04
ฑ0.03
1.03
ฑ0.13
0.14
ฑ0.02
0.61
ฑ0.04
0.14
ฑ0.03
0.10
ฑ0.02
0.03
ฑ0.01
0.51
ฑ0.16
3.45
ฑ0.44
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
17-31
-------
Table 17-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the New Jersey Monitoring Sites (Continued)
Pollutant
Propionaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
#of
Measured
Detections
vs. # of
Samples
61/61
56/61
24/61
4/61
1st
Quarter
Average
(Ug/m3)
0.28
ฑ0.06
0.14
ฑ0.04
0.03
ฑ0.02
<0.01
ฑ<0.01
2nd
Quarter
Average
(Ug/m3)
0.51
ฑ0.14
0.25
ฑ0.09
0.05
ฑ0.04
<0.01
ฑ<0.01
3rd
Quarter
Average
(Ug/m3)
0.67
ฑ0.13
0.24
ฑ0.16
0.27
ฑ0.39
O.01
ฑO.01
4th
Quarter
Average
(Ug/m3)
0.37
ฑ0.09
0.18
ฑ0.05
0.03
ฑ0.02
O.01
ฑO.01
Annual
Average
(Ug/m3)
0.45
ฑ0.06
0.20
ฑ0.05
0.09
ฑ0.09
O.01
ฑO.01
New Brunswick, New Jersey - NBNJ
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
62/62
25/58
58/58
42/58
58/58
48/58
39/58
19/58
58/58
62/62
9/58
50/58
15/58
7/58
2.38
ฑ0.55
0.08
ฑ0.04
0.84
ฑ0.23
0.05
ฑ0.03
0.45
ฑ0.07
0.07
ฑ0.03
0.04
ฑ0.03
<0.01
ฑ0.01
0.24
ฑ0.04
1.41
ฑ0.31
0.03
ฑ0.03
0.10
ฑ0.03
0.02
ฑ0.02
0.01
ฑ0.01
2.90
ฑ0.70
0.14
ฑ0.06
0.65
ฑ0.27
0.03
ฑ0.03
0.56
ฑ0.09
0.17
ฑ0.05
0.10
ฑ0.06
0.03
ฑ0.04
1.22
ฑ1.95
2.70
ฑ2.05
0.02
ฑ0.03
0.16
ฑ0.08
0.03
ฑ0.04
0.01
ฑ0.01
2.74
ฑ0.43
0.17
ฑ0.21
0.51
ฑ0.08
0.04
ฑ0.02
0.69
ฑ0.05
0.16
ฑ0.06
0.07
ฑ0.03
O.01
ฑ0.01
0.39
ฑ0.14
4.94
ฑ4.02
0.01
ฑ0.01
0.11
ฑ0.04
0.02
ฑ0.03
0.01
ฑ0.01
1.92
ฑ0.34
0.02
ฑ0.03
0.76
ฑ0.17
0.08
ฑ0.02
0.63
ฑ0.08
0.11
ฑ0.03
0.05
ฑ0.02
0.06
ฑ0.02
0.28
ฑ0.06
1.98
ฑ1.29
0.01
ฑ0.02
0.13
ฑ0.04
0.02
ฑ0.02
0.01
ฑ0.01
2.49
ฑ0.27
0.09
ฑ0.05
0.70
ฑ0.10
0.06
ฑ0.01
0.59
ฑ0.04
0.13
ฑ0.02
0.06
ฑ0.02
0.03
ฑ0.01
0.49
ฑ0.39
2.71
ฑ1.10
0.02
ฑ0.01
0.13
ฑ0.02
0.02
ฑ0.01
0.01
ฑO.01
Paterson, New Jersey - PANJ
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
2/12
12/12
12/12
12/12
0
1.20
ฑ0.15
0.19
ฑ0.02
0.42
ฑ0.17
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
17-32
-------
Table 17-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the New Jersey Monitoring Sites (Continued)
Pollutant
Chloroform
1 ,2-Dibromoethane
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Hexachloro- 1 , 3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
#of
Measured
Detections
vs. # of
Samples
5/12
3/12
12/12
2/12
12/12
2/12
12/12
7/12
3/12
1st
Quarter
Average
(Ug/m3)
0.05
ฑ0.05
0.01
ฑ0.03
0.13
ฑ0.03
0
0.42
ฑ0.08
0.02
ฑ0.04
0.19
ฑ0.06
0.05
ฑ0.03
0.01
ฑ0.01
2nd
Quarter
Average
(Ug/m3)
NA
NA
NA
NA
NA
NA
NA
NA
NA
3rd
Quarter
Average
(Ug/m3)
NA
NA
NA
NA
NA
NA
NA
NA
NA
4th
Quarter
Average
(Ug/m3)
NA
NA
NA
NA
NA
NA
NA
NA
NA
Annual
Average
(Ug/m3)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
Observations for CHNJ from Table 17-5 include the following:
The pollutants of interest with the highest annual average concentrations by mass are
formaldehyde, acetaldehyde, and carbon tetrachloride. Only the two carbonyl
compounds have annual average concentrations greater than 1 |ig/m3.
Concentrations of formaldehyde appear to be higher during the warmer months, based
on the quarterly averages. The second and third quarter averages are higher than the
other quarterly averages and have significantly large confidence intervals. A review
of the data shows that the maximum formaldehyde concentration was measured on
July 26, 2011 (15.45 |ig/m3). The 18 highest formaldehyde concentrations (those
greater than 2.25 |ig/m3) were all measured between May and September.
Conversely, of the 19 concentrations less than 1 |ig/m3, 17 were measured in the first
quarter, one was measured in the second quarter, and one was measured in the fourth
quarter.
Concentrations of acrylonitrile appear highest during the third quarter of 2011, but the
confidence interval for this average is nearly as high as the average itself. A review of
the data shows that the maximum acrylonitrile concentration was measured on
August 19, 2011 (1.37 |ig/m3) and is an order of magnitude higher than the next
highest concentration (0.294 |ig/m3, measured on August 1, 2011). The three highest
measurements of acrylonitrile were all measured in August.
17-33
-------
Several of the VOCs have third quarter average concentrations that are greater than
the other quarterly average concentrations and/or have relatively large confidence
intervals. For many of these, the maximum concentration was measured on
July 8, 2011. And for most of these, the difference between the July 8, 2011
measurement and the next highest concentration is significant. For example, the
benzene concentration on July 8, 2011 (2.07 |ig/m3) is twice the next highest
concentration (1.01 |ig/m3, measured on December 5, 2011). As a second example,
the tetrachloroethylene concentration measured on July 8, 2011 (1.09 |ig/m3) is nearly
four times higher than the next highest concentration (0.299 |ig/m3, measured on
May 3, 2011). This trend can also be seen in the data for 1,3-butadiene, chloroform,
1,2-dichloroethane, and trichloroethylene. This date was also discussed in
Section 17.3.
Observations for ELNJ from Table 17-5 include the following:
The pollutants of interest with the highest annual average concentrations by mass are
formaldehyde, acetaldehyde, and benzene. These are the only pollutants with annual
average concentrations greater than 1 |ig/m3.
The concentrations of many of the pollutants of interest for ELNJ appear to be higher
during the warmer months of the year, as illustrated by the quarterly average
concentrations, particularly the carbonyl compounds. However, most of the
differences are not statistically significant.
Acrylonitrile was detected in only 11 samples collected at ELNJ and spanned an
order of magnitude (0.0969 |ig/m3to 0.605 |ig/m3). There were two measured
detections during the first quarter, eight in the second quarter, none in the third
quarter, and one in the fourth quarter, which happened to be the maximum
concentration measured at ELNJ. Thus, the fourth quarter average was determined
from one single measurement and 15 non-detects.
The third quarter average ethylbenzene concentration is twice the other quarterly
averages and has a relatively large confidence interval. A review of the data shows
that the maximum concentration of ethylbenzene was measured on July 8, 2011
(5.00 |ig/m3) and is more than five times the next highest concentration
(0.979 |ig/m3). Several of the VOCs were highest on July 8, 2011, including
chloroform, 1,2-dichloroethane, tetrachloroethylene, and trichloroethylene.
Observations for NBNJ from Table 17-5 include the following:
The pollutants of interest with the highest annual average concentrations by mass are
formaldehyde, acetaldehyde, and benzene. Acetaldehyde and formaldehyde are the
only pollutants with annual average concentrations greater than 1 |ig/m3.
The second, third, and fourth quarter average concentrations of formaldehyde have
relatively large confidence intervals associated with them relative to the averages
themselves. Concentrations of formaldehyde measured at NBNJ range from
0.81 |ig/m3to 27.7 |ig/m3. The maximum concentration of formaldehyde was
17-34
-------
measured at NBNJ on September 6, 2011 and is the maximum concentration
measured across the program. Three additional formaldehyde concentrations greater
than 10 |ig/m3 were measured at NBNJ, one each in the second, third, and fourth
quarters of 2011.
The confidence interval associated with third quarter average concentration of
acrylonitrile is larger than the average itself, indicating that the concentration average
is likely influenced by outliers. The maximum concentration of acrylonitrile is
1.34 |ig/m3 and was measured on September 24, 2011. This concentration is more
than four times the next highest concentration measured at NBNJ (0.307 |ig/m3
measured on October 6, 2011). This pollutant was detected in less than half of the
VOC samples collected and concentrations of acrylonitrile range from 0.083 |ig/m3 to
1.34|ig/m3.
The second quarter ethylbenzene concentration is more than three times the other
quarterly averages and its confidence interval is greater than the average itself. A
review of the data shows that the maximum concentration of ethylbenzene was
measured at NBNJ on April 9, 2011 (11.5 |ig/m3). This measurement is more than
10 times the next highest concentration measured at NBNJ (1.07 |ig/m3) and is the
highest concentration measured across the program. Several of the VOCs were
highest on April 9, 2011, including l,2-dichloroethane,/>-dichlorobenzene,
tetrachloroethylene, and trichloroethylene.
Observations for PANJ from Table 17-5 include the following:
VOC sampling at PANJ ended in the middle of May 2011. Thus, only first quarter
average concentrations could be calculated (second quarter concentrations were not
calculated because there were not enough samples collected to meet the completeness
criteria). However, Appendix J provides the pollutant-specific average concentration
for all valid samples collected at PANJ over the entire sample period.
Benzene is the pollutant with the highest first quarter average concentration for PANJ
and is the only pollutant for which a first quarter average is greater than 1 |ig/m3.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the New
Jersey sites from those tables include the following:
The New Jersey sites appear in Table 4-9 for VOCs a total of 23 times (CJrtNJ - 7;
ELNJ - 8; and NBNJ - 8). At least one New Jersey site appears among the rankings
for each of the program-level pollutants of interest and all three New Jersey sites
appear for acrylonitrile, chloroform, 1,2-dichloroethane, and trichloroethylene.
CJrDSTJ has the highest annual average concentration of 1,2-dichloroethane among
NMP sites sampling VOCs. The highest ranking for ELNJ is second for
trichloroethylene; the highest ranking for NBNJ is second for vinyl chloride.
17-35
-------
The New Jersey sites appear in Table 4-10 for carbonyl compounds a total of three
times. ELNJ and NBNJ have the highest and fifth highest annual average
concentrations of acetaldehyde, respectively, while ELNJ has the eighth highest
annual average concentration of formaldehyde.
17.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde, benzene,
1,3-butadiene, and formaldehyde were created for CHNJ, ELNJ, and NBNJ. Box plots were not
created for PANJ because annual averages could not be calculated for this site. Figures 17-19
through 17-22 overlay the sites' minimum, annual average, and maximum concentrations onto
the program-level minimum, first quartile, median, average, third quartile, and maximum
concentrations, as described in Section 3.5.3.
Figure 17-19. Program vs. Site-Specific Average Acetaldehyde Concentrations
CHNJ
ELNJ
NBNJ
6 8 10
Concentration !: r":v
Program: 1st Quartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site:
Site Average Site Minimum/Maximum
17-36
-------
Figure 17-20. Program vs. Site-Specific Average Benzene Concentrations
i Program Max Concentration = 23.8 ug/m3
i Program Max Concentration = 23.8 ug/rm3
NBNJ ^| 1 I Program Max Concentration = 23.8 ug/nv
0123456789
Concentration (|ig/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
D D I
Site: Site Average Site Minimum/Maximum
o
Figure 17-21. Program vs. Site-Specific Average 1,3-Butadiene Concentrations
i i Program Max Concentration = 9.51 ug/m3
^m i [
M_b~. i I prฐgramMa)( Concentration = 9.51 ug/m3
tl ,
NBNJ ^J 1 [ Projjram Max Concentration = 9.51
3.5
1.5
Concentration (
2.5
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
17-37
-------
Figure 17-22. Program vs. Site-Specific Average Formaldehyde Concentrations
NBNJ
15
Concentration (|ig/m3)
25
Program: IstQuartile 2ndQuartile 3rd Quartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 17-19 through 17-22 include the following:
Figure 17-19 shows that while CUNJ's annual average acetaldehyde
concentration is less than the program-level average concentration, the annual
averages for ELNJ and NBNJ are greater than the program-level average
concentration. In addition, the annual average for NBNJ is equivalent to the
program-level third quartile while the annual average for ELNJ is greater than the
program-level third quartile. The range of acetaldehyde measurements is greatest
for ELNJ and least for CFINJ. There were no non-detects of acetaldehyde
measured at the New Jersey sites or across the program.
Figure 17-20 presents the box plots for benzene. Note that the program-level
maximum concentration (23.8 |ig/m3) is not shown directly on the box plots
because the scale of the box plots would be too large to readily observe data
points at the lower end of the concentration range. Thus, the scale has been
reduced to 10 |ig/m3. This figure shows that the annual average benzene
concentration for CFINJ is just greater than the program-level first quartile. This
site has one of the lowest annual average benzene concentrations among sites
sampling benzene. NBNJ's annual average benzene concentration is less the
program-level average but equivalent to the program-level median concentration.
The annual average concentration for ELNJ is just greater than the program-level
average concentration. The range of concentrations measured for ELNJ is roughly
twice the range measured at CFINJ and NBNJ. There were no non-detects of
benzene measured at the New Jersey sites or across the program.
17-38
-------
Figure 17-21 presents the box plots for 1,3-butadiene. Similar to the benzene box
plots, the program-level maximum concentration (9.51 |ig/m3) is not shown
directly on the box plots as the scale has been reduced to 3 |ig/m3 to allow for the
observation of data points at the lower end of the concentration range. The
statistical metrics shown for each site follow a similar trend as the metrics on the
benzene box plots. The annual average 1,3-butadiene concentration for CHNJ is
greater than the program-level first quartile but less than the program-level
median concentration. The annual average concentration for NBNJ is just less
than the program-level median concentration. ELNJ's annual average
concentration is greater than the program-level third quartile. The range of
measurements was smallest for NBNJ and greatest for ELNJ. Non-detects were
measured at all three sites, but the number of non-detects varied significantly.
Approximately half of the 1,3-butadiene measurements at CHNJ were non-
detects, approximately one-quarter of the measurements at NBNJ were non-
detects, and two non-detects were measured at ELNJ.
Figure 17-22 for formaldehyde shows that while the annual average
concentrations of formaldehyde for CHNJ and NBNJ are less than the program-
level average, the annual average for ELNJ is greater than the program-level
average concentration. Even though the range of measurements for ELNJ is the
smallest among the New Jersey sites, ELNJ has the highest annual average
concentration of formaldehyde among the three sites. Although the maximum
formaldehyde concentration measured across the program was measured at
NBNJ, this site's annual average ranked 13th among NMP sites sampling carbonyl
compounds. By comparison, ELNJ ranked 8th and CHNJ 16th. There were no
non-detects of formaldehyde measured at the New Jersey sites or across the
program.
17.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. CHNJ, ELNJ, and NBNJ have sampled VOCs and carbonyl compounds under the
NMP for many years. ELNJ has sampled under the NMP since 2000 and CHNJ and NBNJ since
2001. Thus, Figures 17-23 through 17-34 present the annual statistical metrics for acetaldehyde,
benzene, 1,3-butadiene, and formaldehyde for CHNJ, ELNJ, and NBNJ, respectively. The
statistical metrics presented for assessing trends include the substitution of zeros for non-detects.
Because sampling at PANJ is being conducted for a one-year period ending in May 2011, a
trends analysis could not be performed.
17-39
-------
Figure 17-23. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at CHNJ
1
E
.9
E
Average Concen
) |
0
rh
^*
I r-L F^
'-j-' 1 - .a-, ,=5=, i_o_, ฃ- i-^-. i_^j r-
2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
Figure 17-24. Annual Statistical Metrics for Benzene Concentrations
Measured at CHNJ
*
2003 2004 2005 2006 2007 2008 2DD9 2010 2011
Year
* 5th Percentile - Minimum Median - Maximum 95th Percentile * Average
17-40
-------
Figure 17-25. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at CHNJ
rn
i
[Vincent ration
3 c
I
<
0
_ r
T r
n u i a A r*i i
V" .^H A ^^
1 H^ 1 1 ' t ' 1 ! ! 1 ! ! , ' ' 1 l..fcl , ! 1 ,
2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
- Minimum Median - Maximum 95th Percentile 5th Percentile "^"Average
Figure 17-26. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at CHNJ
1
1
e
.9
E
|
3
3
s
<
0
^^ <
L- l"rป =5= == =^*= i- --1 ^^ i=s=
r
~
rh n rh i r^i ""
' ...t. I.AU ...fa ..fc.1 ซป^ ^^_
2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
* 5th Percentile - Minimum Median - Max mum 95th Percentile . .+.. Average
17-41
-------
Figure 17-27. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at ELNJ
!
I'
e
s
8
*
2001 2002 2003 2004
2005 2006 2007 2008
Year
2009 2010 2011
5th Percentile Minimum Median Maximum
95th Percentile
Average
Figure 17-28. Annual Statistical Metrics for Benzene Concentrations
Measured at ELNJ
The maximum benzene
concentration for 2008
is 34.3 ^g/m3
r
e
.9
B
ซ 8
8
i
ฑ
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
* 5th Percentile - Minimum Median - Maximum 95th Percentile * Average
17-42
-------
Figure 17-29. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at ELNJ
=E
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum
95th Percentile "^"Average
Figure 17-30. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at ELNJ
r
B
a
S S
8
i
I
r T
"r
T
2001 2002 2003 2004
2005 2006 2007 2003 2009 2010 2011
Year
* 5th Percentile - Minimum Median - Maximum
95th Percentile
Average
17-43
-------
Figure 17-31. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at NBNJ
The maximum acetaldehyde
concentration for 2004 is
111 ng/m3
1
r
p
1
r
4
r
m*m
'-?-'
T
1
-
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
# 5th Percentile Minimum Median Maximum 95th Percentile ..^.. Average
Figure 17-32. Annual Statistical Metrics for Benzene Concentrations
Measured at NBNJ
m"
rat ton \wJ\
i L
rage Co nee n
ซE
J
f T
~ฑ
fa +. ... . rn
" 1
ป r*n
i i V^ ^
1 i L,
.
J T
2002 2003 2004 20O5 2006 2007 2008 20O9 2010 2011
Year
* 5th Percentile - Minimum Median - Maximum * 95th Percentile . . ^. . Average
17-44
-------
Figure 17-33. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at NBNJ
"ง 0.3
|
S 0.25
I
3
2002 2003 2004 2005 2006 2007 200S 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile "^"Average
Figure 17-34. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at NBNJ
The maximum
formaldehyde
concentration for
2004 is 96.1 ug/m3.
i
e
.9
s
ฃ :
2002 2003 2004
2005 2006 2007
Year
2008 2009 2010 2011
* 5th Percentile - Minimum Median - Maximum
95th Percentile
Average
17-45
-------
Observations from Figure 17-23 for acetaldehyde measurements at CHNJ include the
following:
Although carbonyl compound sampling at CHNJ began in 2001, sampling did not
begin until May, which does not yield enough samples for the statistical metrics to be
calculated for 2001, based on the criteria specified in Section 3.5.4. In addition, data
from 2002 are not provided due to a completeness less than 85 percent in 2002. Thus,
Figure 17-23 begins with 2003.
The maximum acetaldehyde concentration was measured in 2004. The second and
third highest concentrations were measured in 2004 and 2005; excluding these three
concentrations, all other acetaldehyde concentrations measured at CFDSTJ were less
than 5 |ig/m3.
Although difficult to discern in Figure 17-23, a decreasing trend in the average and
median acetaldehyde concentrations is shown though 2006, after which the median
and average concentrations leveled out until 2011, when an increase is noted.
However, the high concentrations measured in 2004 and 2005 result in confidence
intervals that are relatively large and indicate that these changes are not statistically
significant.
All the statistical metrics calculated exhibit an increase from 2010 to 2011.
There have been no non-detects of acetaldehyde measured at CHNJ over the period
shown.
Observations from Figure 17-24 for benzene measurements at CHNJ include the
following:
Similar to carbonyl compounds, VOC sampling at CHNJ began in 2001. However,
sampling did not begin until May, which does not yield enough samples for the
statistical metrics to be calculated for 2001, based on the criteria specified in
Section 3.5.4. In addition, data from 2002 and 2005 are not provided due to a
completeness less than 85 percent for those years.
Only six benzene concentrations greater than 2 |ig/m3 have been measured at CHNJ
during the years shown. Two were measured in 2008, three in 2009, and one in 2011.
The average and median concentrations exhibit a decreasing trend through 2007,
although no data is shown for 2005. Even though an increase in the average
concentration is shown from 2007 to 2008, confidence intervals calculated indicate
that the changes are not statistically significant. Since 2006, the average concentration
has ranged from 0.47 |ig/m3 (2007) to 0.59 |ig/m3 (2008).
17-46
-------
Observations from Figure 17-25 for 1,3-butadiene measurements at CHNJ include the
following:
The maximum 1,3-butadiene concentration shown was measured in 2003 and is
nearly twice the next highest concentration, which was measured in 2008. The third
highest concentration was measured in 2011. Only five concentrations measured at
CHNJ are greater than 0.2 |ig/m3.
For 2003 and 2004, the minimum, first quarter, and median concentrations are all
zero. This is because 88 percent of the measurements were non-detects for 2003 and
96 percent were non-detects for 2004. The percentage of non-detects decreased to less
than 40 percent for 2006; this decrease continued, reaching a minimum in 2008, after
which an increasing number of non-detects was reported. For 2010, the median was
again zero, indicating that at least 50 percent of the measurements were non-detects.
The average and median concentrations have a decreasing trend from 2008 through
2010. All of the statistical metrics exhibit an increase for 2011.
Observations from Figure 17-26 for formaldehyde measurements at CFDSTJ include the
following:
The statistical metrics presented for formaldehyde mimic those for acetaldehyde in
Figure 17-23 in regards to trending.
The maximum formaldehyde concentration was measured in 2004. This concentration
of formaldehyde is nearly four times the maximum concentrations shown for other
periods excluding 2004. The second highest concentration was also measured in
2004, but was nearly half the magnitude. These two maximum concentrations were
measured on the same days as the maximum acetaldehyde concentrations. The third
highest concentration of formaldehyde was measured in 2011, although similar
concentrations were also measured in 2003 and 2007.
Although difficult to discern in Figure 17-26, a decreasing trend in the average and
median formaldehyde concentrations is shown though 2006, after which the median
and average concentrations leveled out until 2010, when the average concentration
reached a minimum. The average concentration then increased for 2011. However,
the high concentrations measured in 2004 result in confidence intervals that are
relatively large, making the identification of trends difficult.
Similar to acetaldehyde, all of the statistical metrics calculated for formaldehyde
exhibit an increase from 2010 to 2011. The 95th percentile for 2011 is greater than the
maximum concentration for 2010.
There have been no non-detects of formaldehyde measured at CHNJ over the period
shown.
17-47
-------
Observations from Figure 17-27 for acetaldehyde measurements at ELNJ include the
following:
ELNJ is the longest running UATMP site. Carbonyl compound sampling at ELNJ
began in January 2000. However, sporadic sampling at the beginning of 2000
combined with a l-in-12 day sampling schedule led to a completeness less than
85 percent. Thus, Figure 17-27 begins with 2001. Completeness was also low in 2003
due to a 1-month period when samples were not collected in January 2003; thus, no
2003 data are presented in Figure 11-21.
The maximum acetaldehyde concentration shown was measured in 2007, although a
concentration of similar magnitude was also measured in 2005. In total, 22
concentrations greater than 10 |ig/m3 have been measured at ELNJ, all of which were
measured prior to 2008.
The average concentration of acetaldehyde has a steadily increasing trend through
2007, after which a significant decrease is exhibited. Although an increasing trend is
also shown between 2008 and 2011, these averages are roughly half the magnitude of
those shown before 2008.
There have been no non-detects of acetaldehyde measured at ELNJ over the period
shown.
Observations from Figure 17-28 for benzene measurements at ELNJ include the
following:
VOC sampling at ELNJ began in January 2000. However, sporadic sampling at the
beginning of 2000 combined with a l-in-12 day sampling schedule led to a
completeness less than 85 percent. Thus, Figure 17-28 also begins with 2001.
The maximum benzene concentration (34.3 |ig/m3) was measured in 2008 and is
more than four times higher than the next highest concentration (measured in 2009).
The third highest concentration was also measured in 2009. Only five benzene
concentrations greater than 5 |ig/m3 have been measured at ELNJ.
A decreasing trend in the average and median concentrations is shown through 2007.
With the exception of the median concentration, all of the statistical parameters
exhibit an increase for 2008. If the maximum concentration for 2008 was removed
from the data set, the average concentration would exhibit a negligible increase for
2008. Thus, it is this single concentration that is driving the average concentration.
The median concentration is influenced less by outliers, as this statistical parameter
represents the midpoint, or 50th percentile, of a data set. That the median did not
change between 2007 and 2008 is further proof that this single outlier is driving the
average concentration upward.
17-48
-------
Even though some of the highest concentrations were measured in 2009, as indicated
by the maximum and 95th percentile, the average concentration decreased from 2008
to 2009, likely a result of the sheer magnitude of the outlier affecting the 2008
calculations.
Figure 17-28 shows that benzene concentrations for 2010 and 2011 returned to levels
similar to 2007.
Observations from Figure 17-29 for 1,3-butadiene measurements at ELNJ include the
following:
The maximum concentration of 1,3-butadiene was measured in 2009 and is nearly
two and a half times the next highest concentration (measured in 2001). These two
concentrations are the only concentrations of 1,3-butadiene measured at ELNJ greater
than 1 |ig/m3.
Figure 17-29 shows a decreasing trend in the average concentration through 2004,
then a leveling off of average concentrations that continues through the 2011. Even
with the higher concentration measured in 2009, the average concentration for 2009 is
similar to the average concentration for 2008. Between 2004 and 2011, the average
concentration has ranged from 0.11 |ig/m3 (2004) to 0.16 |ig/m3 (2009).
Even with the maximum concentration measured in 2009, the difference between the
5th and 95th percentiles has been decreasing since the onset of sampling, reaching a
minimum in 2011. This indicates an overall decrease in the majority of concentrations
measured at ELNJ.
Observations from Figure 17-30 for formaldehyde measurements at ELNJ include the
following:
The maximum formaldehyde concentration shown was measured in 2010, as was the
second highest concentration. A total of 11 concentrations greater than 10 |ig/m3 have
been measured at ELNJ.
Figure 17-30 shows that there was an increase in formaldehyde concentrations from
2002 to 2004, although there is no data shown for 2003. Between 2004 and 2007,
there was relatively little change in the average formaldehyde concentration. Similar
to acetaldehyde, the average concentration of formaldehyde decreased significantly
between 2007 and 2008, after which an increasing trend is shown. While the trends
graph for acetaldehyde shows a continued increase for 2011, the average
formaldehyde concentration decreased for 2011.
Observations from Figure 17-31 for acetaldehyde measurements atNBNJ include the
following:
Although carbonyl compound sampling at NBNJ began in 2001, sampling did not
begin until May, which does not yield enough samples for the statistical metrics to be
17-49
-------
calculated for 2001, based on the criteria specified in Section 3.5.4. Thus,
Figure 17-31 begins with 2002.
The maximum acetaldehyde concentration was measured in 2004. This concentration
(111 |ig/m3) is nearly seven times higher, and an order of magnitude higher, than the
next highest concentration (16.2 |ig/m3 measured in 2005).
Of the 29 concentrations greater than 8 |ig/m3, 28 were measured in 2004 or 2005
(and the other was measured in 2008). This, along with the outlier concentration
measured in 2004, explains the significant increase in the statistical metrics from
2003 to 2004. Even without an outlier for 2005, most of the statistical metrics for
2005 exhibit slight increases from 2004 levels. The average, however, does not. If the
outlier was removed from the data set for 2004, the average concentration for 2004
would be slightly less than the average concentration for 2005.
The average concentration decreases significantly from 2005 to 2006 and reaches a
minimum for 2007, as do all of the other statistical parameters. After 2007, the
average concentration fluctuates between 2 |ig/m3 and 3 |ig/m3.
There have been no non-detects of acetaldehyde measured at NBNJ.
Observations from Figure 17-32 for benzene measurements at NBNJ include the
following:
VOC sampling at NBNJ also began in May 2001. Because seven months of sampling
does not yield enough samples for the statistical metrics to be calculated for 2001,
based on the criteria specified in Section 3.5.4, Figure 17-32 also begins with 2002.
The maximum benzene concentration was measured in 2002, but similar
concentrations were also measured in 2005 and 2009. These are the only three
concentrations of benzene greater than 3 |ig/m3 measured at NBNJ.
Although a slight decreasing trend is shown between 2002 and 2004, a significant
decrease is shown between 2005 and 2007, where several of the statistical parameters
reached a minimum. The average concentration increased slightly for 2008, after
which little change is observed. The average concentration ranges from 0.65 |ig/m3
(2010) to 0.70 |ig/m3 (2011) between 2008 and 2011.
Observations from Figure 17-33 for 1,3-butadiene measurements at NBNJ include the
following:
The maximum 1,3-butadiene concentration was measured in 2005 and is the only
measurement greater than 0.35 |ig/m3 measured at NBNJ.
The minimum, 5th percentile, and median concentrations are all zero for 2002 through
2004. This indicates that at least 50 percent of the measurements were non-detects for
these years. The number of non-detects began to decrease in 2005 (47 percent) and
17-50
-------
reached a minimum in 2008 (2 percent). The number of non-detects increased to
29 percent for 2011. The increase in non-detects for 2011 is evident, at least in part,
from the decrease in the 5th percentile shown from 2010 to 2011.
The average concentration of 1,3-butadiene at NBNJ decreased significantly from
2003 to 2004. This is likely a result of the change in the number of non-detects as
well as a reduction in the range of measurements. The number of non-detects
increased from 69 percent to greater than 90 percent from 2003 to 2004. Thus, many
zeros were substituted into this average. Conversely, the increase in the average
concentration shown from 2004 to 2005 results from a combination of fewer non-
detects and a larger range of measurements. The average concentration of
1,3-butadiene after 2004 exhibits little change and ranges from 0.046 |ig/m3 (2009) to
0.057 |ig/m3 (2008).
Observations from Figure 17-34 for formaldehyde measurements at NBNJ include the
following:
The maximum formaldehyde concentration (96.1 |ig/m3) was measured on the same
day in 2004 that the highest acetaldehyde concentration was measured
(August 31, 2004). This concentration of formaldehyde is more than three times the
next highest concentration (27.7 |ig/m3, measured in 2011). Concentrations greater
than 20 |ig/m3 have been measured in 2004, 2006, 2009, and 2011.
Similar to acetaldehyde, several of the statistical metrics exhibit increases from 2003
to 2004. Also similar to acetaldehyde, while the average concentration decreased
from 2004 to 2005, many of the other statistical metrics did not, indicating that
concentrations on a whole were higher in 2005 and not just influenced by outlier(s).
After 2005, concentrations of formaldehyde decreased steadily, reaching a minimum
in 2008. This year also had the smallest range of formaldehyde measurements. After
2008, the average concentration fluctuated. Although the average concentration for
2011 is not statistically different than the average concentrations for the last few years
of sampling, the 95th percentile for 2011 increased significantly, doubling or tripling
compared to previous years. This indicates that more of the measurements are falling
into a higher range than in previous years.
17.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each New Jersey monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
17-51
-------
17.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the New
Jersey monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
17.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the New Jersey sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 17-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
17-52
-------
Table 17-6. Risk Approximations for the New Jersey Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Chester, New Jersey - CHNJ
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0000078
0.00003
0.000006
0.000026
0.000013
0.000022
0.00000026
0.0000048
0.0000088
0.009
0.002
0.03
0.002
0.1
0.098
2.4
0.0098
0.09
0.04
0.002
0.1
61/61
35/61
61/61
31/61
61/61
50/61
19/61
61/61
6/61
40/61
5/61
5/61
1.61
ฑ0.20
0.10
ฑ0.05
0.53
ฑ0.07
0.02
ฑ0.01
0.62
ฑ0.03
0.10
ฑ0.03
0.03
ฑ0.02
2.37
ฑ0.63
0.01
ฑ0.01
0.09
ฑ0.04
0.05
ฑ0.09
<0.01
ฑ<0.01
3.55
7.13
4.12
0.71
3.74
0.88
30.80
0.24
0.02
0.23
0.02
0.18
0.05
0.02
0.01
0.01
0.01
0.01
0.24
0.01
O.01
0.02
O.01
Elizabeth, New Jersey - ELNJ
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
0.0000022
0.000068
0.0000078
0.00003
0.000006
0.000011
0.000026
0.0000025
0.000013
0.009
0.002
0.03
0.002
0.1
0.098
0.8
2.4
1
0.0098
61/61
11/61
61/61
59/61
61/61
48/61
49/61
16/61
61/61
61/61
3.24
ฑ0.39
0.04
ฑ0.03
1.03
ฑ0.13
0.14
ฑ0.02
0.61
ฑ0.04
0.14
ฑ0.03
0.10
ฑ0.02
0.03
ฑ0.01
0.51
ฑ0.16
3.45
ฑ0.44
7.14
2.50
8.00
4.05
3.68
1.10
0.73
1.27
44.84
0.36
0.02
0.03
0.07
0.01
O.01
0.01
O.01
0.01
0.35
NA = Not available due to the criteria for calculating an annual average
= a Cancer URE or Noncancer RfC is not available
17-53
-------
Table 17-6. Risk Approximations for the New Jersey Monitoring Sites (Continued)
Pollutant
Propionaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Cancer
URE
(Hg/m3)1
0.00000026
0.0000048
0.0000088
Noncancer
RfC
(mg/m3)
0.008
0.04
0.002
0.1
#of
Measured
Detections
vs. # of
Samples
61/61
56/61
24/61
4/61
Annual
Average
(Hg/m3)
0.45
ฑ0.06
0.20
ฑ0.05
0.09
ฑ0.09
0.01
ฑ0.01
Cancer Risk
Approximation
(in-a-million)
0.05
0.45
0.01
Noncancer
Hazard
Approximation
(HQ)
0.06
0.01
0.05
0.01
New Brunswick, New Jersey - NBNJ
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0000078
0.00003
0.000006
0.000011
0.000026
0.0000025
0.000013
0.000022
0.00000026
0.0000048
0.0000088
0.009
0.002
0.03
0.002
0.1
0.098
0.8
2.4
1
0.0098
0.09
0.04
0.002
0.1
62/62
25/58
58/58
42/58
58/58
48/58
39/58
19/58
58/58
62/62
9/58
50/58
15/58
7/58
2.49
ฑ0.27
0.09
ฑ0.05
0.70
ฑ0.10
0.06
ฑ0.01
0.59
ฑ0.04
0.13
ฑ0.02
0.06
ฑ0.02
0.03
ฑ0.01
0.49
ฑ0.39
2.71
ฑ 1.10
0.02
ฑ0.01
0.13
ฑ0.02
0.02
ฑ0.01
O.01
ฑO.01
5.47
6.20
5.45
1.66
3.52
0.68
0.79
1.23
35.23
0.33
0.03
0.11
0.03
0.28
0.05
0.02
0.03
0.01
O.01
0.01
O.01
0.01
0.28
0.01
O.01
0.01
O.01
Paterson, New Jersey - PANJ
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
0.000068
0.0000078
0.00003
0.000006
0.002
0.03
0.002
0.1
2/12
12/12
12/12
12/12
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA = Not available due to the criteria for calculating an annual average
= a Cancer URE or Noncancer RfC is not available
17-54
-------
Table 17-6. Risk Approximations for the New Jersey Monitoring Sites (Continued)
Pollutant
Chloroform
1 ,2-Dibromoethane
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Hexachloro- 1 , 3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Cancer
URE
(Hg/m3)1
0.0006
0.000011
0.000026
0.0000025
0.000022
0.00000026
0.0000048
0.0000088
Noncancer
RfC
(mg/m3)
0.098
0.009
0.8
2.4
1
0.09
0.04
0.002
0.1
#of
Measured
Detections
vs. # of
Samples
5/12
3/12
12/12
2/12
12/12
2/12
12/12
7/12
3/12
Annual
Average
(Hg/m3)
NA
NA
NA
NA
NA
NA
NA
NA
NA
Cancer Risk
Approximation
(in-a-million)
NA
NA
NA
NA
NA
NA
NA
NA
NA
Noncancer
Hazard
Approximation
(HQ)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA = Not available due to the criteria for calculating an annual average
- = a Cancer URE or Noncancer RfC is not available
Observations from Table 17-6 include the following:
For CHNJ, the pollutants with the highest annual averages are formaldehyde,
acetaldehyde, and carbon tetrachloride. Formaldehyde has the highest cancer risk
approximation for this site, followed by acrylonitrile and benzene. The cancer risk
approximation for formaldehyde is at least an order of magnitude higher than the
approximations for the other pollutants of interest. None of the pollutants of interest
for CHNJ have noncancer hazard approximations greater than 1.0, indicating that no
adverse health effects are expected from these individual pollutants.
For ELNJ, the pollutants with the highest annual averages are formaldehyde,
acetaldehyde, and benzene. These three pollutants also have the highest cancer risk
approximations for this site, although the cancer risk approximation for benzene is
greater than the cancer risk approximation for acetaldehyde. None of the pollutants of
interest for ELNJ have noncancer hazard approximations greater than 1.0, indicating
that no adverse health effects are expected from these individual pollutants.
For NBNJ, the pollutants with the highest annual averages are formaldehyde,
acetaldehyde, and benzene. Formaldehyde has the highest cancer risk approximation
for NBNJ, followed by acrylonitrile and acetaldehyde (with benzene nearly
equivalent to acetaldehyde). None of the pollutants of interest for NBNJ have
noncancer hazard approximations greater than 1.0, indicating that no adverse health
effects are expected from these individual pollutants.
17-55
-------
Because annual averages could not be calculated for PANJ, cancer risk and noncancer
hazard approximations could not be calculated either.
17.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 17-7 and 17-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 17-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 17-6. Table 17-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations, also calculated from annual averages provided in
Table 17-6.
The pollutants listed in Tables 17-7 and 17-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 17.3, CHNJ, ELNJ, and NBNJ sampled for VOCs and carbonyl compounds. In addition,
the cancer risk and noncancer hazard approximations are limited to those pollutants with enough
data to meet the criteria for annual averages to be calculated. The completeness criteria were not
met by PANJ because of the short sampling duration; as a result, annual averages, and thus
cancer risk and noncancer hazard approximations, were not calculated for this site. A more in-
depth discussion of this analysis is provided in Section 3.5.5.3. Similar to the cancer risk and
noncancer hazard approximations, this analysis may help policy-makers prioritize their air
monitoring activities.
17-56
-------
Table 17-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the New Jersey Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Chester, New Jersey (Morris County) - CHNJ
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group la
POM, Group 6
207.44
118.39
111.67
75.87
32.41
12.97
9.08
1.98
0.32
0.16
Benzene
Formaldehyde
1,3 -Butadiene
Naphthalene
Hexavalent Chromium, PM
Ethylbenzene
POM, Group 2b
Acetaldehyde
Arsenic, PM
POM, Group 3
1.62E-03
1.45E-03
9.72E-04
4.41E-04
3.11E-04
2.96E-04
1.74E-04
1.67E-04
1.31E-04
1.24E-04
Formaldehyde
Acrylonitrile
Benzene
Carbon Tetrachloride
Acetaldehyde
1 ,2-Dichloroethane
1,3 -Butadiene
Hexachloro- 1 ,3 -butadiene
Trichloroethylene
Tetrachloroethylene
30.80
7.13
4.12
3.74
3.55
0.88
0.71
0.24
0.23
0.02
Elizabeth, New Jersey (Union County) - ELNJ
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
Dichloromethane
1,3 -Butadiene
Naphthalene
POM, Group 2b
Nickel, PM
Propylene oxide
160.93
111.28
89.90
67.31
41.31
23.48
11.41
1.57
1.36
0.70
Formaldehyde
Benzene
1,3 -Butadiene
Nickel, PM
Hexavalent Chromium, PM
Naphthalene
Arsenic, PM
Ethylbenzene
Acetaldehyde
POM, Group 2b
1.45E-03
1.26E-03
7.04E-04
6.52E-04
6.03E-04
3.88E-04
2.37E-04
2.25E-04
1.48E-04
1.38E-04
Formaldehyde
Benzene
Acetaldehyde
1,3 -Butadiene
Carbon Tetrachloride
Acrylonitrile
Ethylbenzene
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Trichloroethylene
44.84
8.00
7.14
4.05
3.68
2.50
1.27
1.10
0.73
0.45
-------
Table 17-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the New Jersey Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
New Brunswick, New Jersey (Middlesex County) - NBNJ
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Ethylene oxide
Tetrachloroethylene
263.33
175.06
146.78
107.72
40.00
20.62
7.26
2.82
1.05
0.96
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
Hexavalent Chromium, PM
Ethylbenzene
Nickel, PM
POM, Group 2b
Acetaldehyde
Arsenic, PM
2.28E-03
2.05E-03
1.20E-03
7.01E-04
4.61E-04
3.67E-04
2.67E-04
2.48E-04
2.37E-04
1.84E-04
Formaldehyde
Acrylonitrile
Acetaldehyde
Benzene
Carbon Tetrachloride
1,3 -Butadiene
Ethylbenzene
1 ,2-Dichloroethane
ฃ>-Dichlorobenzene
Hexachloro- 1 ,3 -butadiene
35.23
6.20
5.47
5.45
3.52
1.66
1.23
0.79
0.68
0.33
Paterson, New Jersey (Passaic County) - PANJ
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group la
POM, Group 6
115.84
63.19
62.14
41.52
17.51
7.26
3.63
1.09
0.32
0.09
Benzene
Formaldehyde
1,3 -Butadiene
Naphthalene
Hexavalent Chromium, PM
Ethylbenzene
POM, Group 2b
Acetaldehyde
POM, Group 3
Arsenic, PM
9.04E-04
8.08E-04
5.25E-04
2.47E-04
1.63E-04
1.58E-04
9.60E-05
9.14E-05
8.90E-05
7.09E-05
oo
-------
Table 17-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the New Jersey Monitoring Sites
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Chester, New Jersey (Morris County) - CHNJ
Toluene
Xylenes
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Ethylene glycol
Naphthalene
624.27
493.82
207.44
131.84
118.39
111.67
75.87
32.41
29.66
12.97
Acrolein
1,3 -Butadiene
Formaldehyde
Acetaldehyde
Benzene
Xylenes
Lead, PM
Naphthalene
Arsenic, PM
Propionaldehyde
302,596.87
16,206.30
11,395.19
8,429.94
6,914.65
4,938.24
4,349.55
4,323.69
2,026.03
1,006.84
Formaldehyde
Acetaldehyde
Acrylonitrile
Trichloroethylene
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Tetrachloroethylene
Chloroform
Hexachloro- 1 ,3 -butadiene
0.24
0.18
0.05
0.02
0.02
0.01
0.01
0.01
0.01
0.01
Elizabeth, New Jersey (Union County) - ELNJ
Toluene
Xylenes
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Dichloromethane
Ethylene glycol
Hydrochloric acid
471.64
352.06
160.93
111.28
109.81
89.90
67.31
41.31
36.52
24.34
Acrolein
Nickel, PM
1,3 -Butadiene
Formaldehyde
Acetaldehyde
Benzene
Naphthalene
Manganese, PM
Arsenic, PM
Xylenes
267,278.15
15,081.94
11,739.58
11,354.92
7,478.86
5,364.23
3,803.12
3,755.20
3,671.47
3,520.63
Acetaldehyde
Formaldehyde
1,3 -Butadiene
Propionaldehyde
Trichloroethylene
Benzene
Acrylonitrile
Carbon Tetrachloride
Tetrachloroethylene
Chloroform
0.36
0.35
0.07
0.06
0.05
0.03
0.02
0.01
0.01
0.01
VO
-------
Table 17-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the New Jersey Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
New Brunswick, New Jersey (Middlesex County) - NBNJ
Toluene
Xylenes
Benzene
Hexane
Formaldehyde
Ethylbenzene
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
Glycol ethers, gas
776.52
593.79
263.33
227.61
175.06
146.78
107.72
49.05
40.00
37.20
Acrolein
1,3 -Butadiene
Formaldehyde
Manganese, PM
Acetaldehyde
Benzene
Naphthalene
Titanium tetrachloride
Nickel, PM
Xylenes
445,148.01
20,000.36
17,862.97
12,571.41
11,968.98
8,777.75
6,872.93
6,385.00
6,175.26
5,937.95
Formaldehyde
Acetaldehyde
Acrylonitrile
1,3 -Butadiene
Benzene
Trichloroethylene
Carbon Tetrachloride
Tetrachloroethylene
Chloroform
Ethylbenzene
0.28
0.28
0.05
0.03
0.02
0.01
0.01
0.00
0.00
0.00
Paterson, New Jersey (Passaic County) - PANJ
Toluene
Xylenes
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
Glycol ethers, gas
358.91
286.81
115.84
71.05
63.19
62.14
41.52
29.87
17.51
13.40
Acrolein
1,3 -Butadiene
Formaldehyde
Acetaldehyde
Benzene
Xylenes
Naphthalene
Arsenic, PM
Lead, PM
Glycol ethers, gas
154,681.77
8,754.09
6,341.18
4,613.84
3,861.24
2,868.11
2,419.97
1,099.65
797.37
670.22
-------
Observations from Table 17-7 include the following:
Benzene is the highest emitted pollutant with a cancer URE in all four New Jersey
counties, followed by ethylbenzene, formaldehyde, and acetaldehyde (although not
necessarily in that order).
Benzene, formaldehyde, and 1,3-butadiene are the pollutants with the highest
toxi city-weighted emissions (of the pollutants with cancer UREs) for all four New
Jersey counties, although not necessarily in that order.
Seven of the 10 highest emitted pollutants in Morris, Middlesex, and Passaic Counties
also have the highest toxi city-weighted emissions while eight of the highest emitted
pollutants in Union County also have the highest toxicity-weighted emissions.
Formaldehyde is the pollutant with the highest cancer risk approximations for CFINJ,
ELNJ, and NBNJ. This pollutant also appears at or near the top of both emissions-
based lists. Acetaldehyde, benzene, and 1,3-butadiene also appear on all three lists for
these sites. Conversely, carbon tetrachloride and acrylonitrile appear on neither
emissions-based list for the New Jersey sites but appear among the pollutants with the
highest cancer risk approximations for each site.
Observations from Table 17-8 include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs for all four New Jersey counties.
Acrolein is the pollutant with the highest toxicity-weighted emissions (of the
pollutants with noncancer RfCs) for all four counties but is not among the highest
emitted pollutants for any of the New Jersey counties. Although acrolein was sampled
for at all four sites, this pollutant was excluded from the pollutant of interest
designation, and thus subsequent risk-based screening evaluations, due to questions
about the consistency and reliability of the measurements, as discussed in Section 3.2.
Behind acrolein, 1,3-butadiene and formaldehyde have the highest noncancer
toxicity-weighted emissions for three of the four New Jersey counties. For Union
County (ELNJ), nickel has the second highest noncancer toxicity-weighted emissions,
followed by 1,3-butadiene and formaldehyde.
The number of pollutants in common between the highest emitted pollutants and
those with the highest toxicity-weighted emissions ranged from four (Union County)
to six (Passaic and Morris Counties).
Formaldehyde and acetaldehyde are among the pollutants with the highest noncancer
hazard approximations for CFINJ, ELNJ, and NBNJ (although all were less than an
HQ of 1.0). These pollutants also appear among the pollutants with the highest
emissions and toxicity-weighted emissions for all four counties. Benzene and
1,3-butadiene also appear on all three lists for these sites.
17-61
-------
17.6 Summary of the 2011 Monitoring Data for the New Jersey Monitoring Sites
Results from several of the data treatments described in this section include the
following:
ปซป Seventeen pollutants failed at least one screen for CHNJ; 16 failed screens for ELNJ;
18 failed screens for NBNJ; and 10 failed screens for PANJ.
ปซป Formaldehyde and acetaldehyde had the highest annual average concentrations for
CHNJ, ELNJ, and NBNJ. Annual average concentrations could not be calculated for
PANJ.
ปซป The annual average acetaldehyde concentration for ELNJ is the highest annual
average among NMP sites sampling this pollutant. The maximum concentration of
formaldehyde measured across the program was measured at NBNJ.
ปซป Several of the pollutants for which a trends analysis was performed exhibit slight
increasing trends from 2010 to 2011 for the New Jersey sites.
17-62
-------
18.0 Sites in New York
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS sites in New York, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
18.1 Site Characterization
This section characterizes the New York monitoring sites by providing geographical and
physical information about the locations of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
The New York monitoring sites are located in New York City (MONY) and Rochester
(ROCH). Figures 18-1 and 18-3 are composite satellite images retrieved from ArcGIS Explorer
showing the monitoring sites in their urban locations. Figures 18-2 and 18-4 identify nearby
point source emissions locations by source category, as reported in the 2008 NEI for point
sources. Note that only sources within 10 miles of the sites are included in the facility counts
provided in Figures 18-2 and 18-4. A 10-mile boundary was chosen to give the reader an
indication of which emissions sources and emissions source categories could potentially have a
direct effect on the air quality at the monitoring sites. Further, this boundary provides both the
proximity of emissions sources to the monitoring sites as well as the quantity of such sources
within a given distance of the sites. Sources outside the 10-mile radius are still visible on each
map, but have been grayed out in order to show emissions sources just outside the boundary.
Table 18-1 provides supplemental geographical information such as land use, location setting,
and locational coordinates.
18-1
-------
Figure 18-1. New York City, New York (MONY) Monitoring Site
oo
to
-------
Figure 18-2. NEI Point Sources Located Within 10 Miles of MONY
73-55VW 73'50'Q"W 73'45'0*W 73'40'0-W
Legend
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
MONY NATTS site
Source Category Group (No. of Facilities)
Abtastve Product Manufacturing (1)
?'? Air-condrtioning/Refrigeralion (3)
& Aircraft Operations (21)
& Automobite'Truck Manufacturing (1)
$ Bake^(l)
B Bulk Terminals/Bulk Plants (2)
C Chemical Manufacturing (5)
6 Etectrical Equipment (2)
ฃ Electncity Generation via Combustion (16)
E Electroplating. Plating, Polishing. Anodizing, & Coloring (1)
ฉ Fabricated Metal Products (2)
?ฃ" Flexibte Polyurethane Foam Production (2)
F Food Processing/Agriculture (3)
fl~ Gasoline/Diesel Service Station (3)
i-V Heating Equipment Manufacturing (2)
O Hospital (4)
10 mile radius | | County boundary
^ Industrial Ma.chinery and Equipment (1)
O Institutional prison (1)
^ Institutional - school (21)
? Miscellaneous Commercial/Industrial (26)
M Miscellaneous Manufacturing (11)
Oil and/or Gas Production (1)
en Pharmaceutical Manufacturing (2)
^ Printing, Coating & Dyeing of Fabric (1)
P Printing/Publishing (10)
B Pulp and Paper Pinny Wood Products <5)
R Rubber and Miscellaneous Plastics Products (2)
^ Ship Building and Repairing (1)
> Solid Wasle D4Sposal - CommorciaVlnstilutional (1)
S Surface Coating (5)
T Tex tile Mil I (2)
/ I-,'.-. j!>- Treatment (G)
18-3
-------
Figure 18-3. Rochester, New York (ROCH) Monitoring Site
oo
-------
Figure 18-4. NEI Point Sources Located Within 10 Miles of ROCH
Legend
77"35'0'W 77'3010"W 77'25XTW
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
ROCH NATTS site O 10 mile radius ] County boundary
Source Category Group (No. of Facilities)
Air-conditioning/Refrigeration (1)
f1 Aircraft Operations (6)
c Chemical Manufacturing (2)
f Electricity Generation via Combustion (1}
t< Heating Equipment Manufacturing (2)
Landfill (2)
P Printing/Publishing (2)
R Rubber and Miscellaneous Plastics Products (1)
* Wastewater Treatment (1)
18-5
-------
Table 18-1. Geographical Information for the New York Monitoring Sites
Site
Code
MONY
ROCH
AQS Code
36-005-0080
36-055-1007
Location
New York
Rochester
County
Bronx
Monroe
Micro- or
Metropolitan
Statistical Area
New York-
Northern New
Jersey-Long Island,
NY-NJ-PAMSA
(New York Div)
Rochester, NY
MSA
Latitude
and
Longitude
40.83606,
-73.92009
43.146198,
-77.54813
Land Use
Residential
Residential
Location
Setting
Urban/City
Center
Urban/City
Center
Additional Ambient Monitoring Information1
Carbonyl Compounds, VOCs, Meteorological
Parameters, Black carbon, PM10 Speciation, PM25.
CO, SO2, VOCs, Carbonyl compounds, O3,
Meteorological parameters, Black Carbon, PM10,
PM10 Speciation, PM25, and PM25 Speciation.
BOLD ITALICS = EPA-designated NATTS Site
oo
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The MONY site is located at the Morrisania Neighborhood Family Care center. This site
is considered the Bronx (#2) NATTS site and is a relocation of the previous location. MONY is
located less than three-quarters of a mile south of 1-95, one-half mile east of 1-87 and east of the
Harlem River, which separates the island of Manhattan from the Bronx. Part of the Harlem River
can be seen in the upper left-hand corner of Figure 18-1. The Hudson River is just a few blocks
farther west. The area surrounding MONY is primarily residential, although commercial areas
are located along Jerome Avenue and East 167th Street. Figure 18-2 shows the numerous point
sources that are located within 10 miles of the site. The bulk of the emissions sources are located
to the south and west of the site. The source categories with the highest number of emissions
sources surrounding MONY include aircraft operations, which include airports as well as small
runways, heliports, or landing pads; electricity generation via combustion; schools; and printing
and publishing. The point source closest to MONY is a medical school.
ROCH is located on the east side of Rochester, in western New York, at a power
substation. Rochester is approximately halfway between Syracuse and Buffalo, and Lake
Ontario lies to the north. Although the area north and west of the site is primarily residential, as
shown in Figure 18-3, a railroad transverses the area just south of the site, and 1-590 and 1-490
intersect farther south with commercial areas adjacent to this corridor. The site is used by
researchers from several universities for short-term air monitoring studies and is the Rochester
NATTS site. As Figure 18-4 shows, the relatively few point sources within a 10-mile radius of
ROCH are located primarily on the west side of the 10-mile radius. The aircraft operations
source category is the category with the highest number of emissions sources surrounding
ROCH, although there are also landfills, chemical manufacturers, printing and publishing
facilities, and heating equipment manufacturers nearby, to name a few.
Table 18-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the New York monitoring sites. Table 18-2 includes county-level
population and vehicle registration information. Table 18-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 18-2 also
18-7
-------
contains traffic volume information for each site. Finally, Table 18-2 presents the county-level
daily VMT for Bronx and Monroe Counties.
Table 18-2. Population, Motor Vehicle, and Traffic Information for the New York
Monitoring Sites
Site
MONY
ROCH
Estimated
County
Population1
1,392,002
745,625
County-level
Vehicle
Registration2
246,748
550,992
Vehicles per
Person
(Registration:
Population)
0.18
0.74
Population
within 10
miles3
5,684,739
650,600
Estimated
10-mile
Vehicle
Ownership
1,007,684
480,772
Annual
Average
Daily
Traffic4
91,465
86,198
County-
level Daily
VMT5
9,698,000
17,772,000
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the New York State DMV (NYS DMV, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2010 data from the New York State DOT (NYS DOT, 2010)
5 County-level VMT reflects 2009 data from the New York State DOT (NYS DOT, 2012)
BOLD ITALICS = EPA-designaled NATTS Site
Observations from Table 18-2 include the following:
Bronx County has the ninth highest county-level population among counties with
NMP sites, but the 10-mile radius population for MONY is the highest among all
NMP sites.
County-level vehicle ownership for Bronx County is in the middle of the range
among NMP sites. Although the 10-mile ownership estimate is one of the highest
estimates among NMP sites, given the large population living within 10 miles of
MONY, the vehicle-per-person ratio is very low (0.18), which is the lowest vehicle-
per-person ratio calculated. This may seem surprising given the high population, but
may be explained by the use of mass transportation systems.
The population surrounding ROCH is lower than the population surrounding MONY.
However, the county-level vehicle ownership for ROCH is double the vehicle
ownership near MONY. The same is not true of the 10-mile ownership estimates. The
county-level and 10-mile population and vehicle ownership data for ROCH are in the
middle of the range compared to other NMP sites.
rth
The traffic volume near MONY and ROCH are not that different from each other.
Compared to other NMP sites, the traffic volumes near MONY and ROCH rank 171
and 18th, respectively. The traffic data for MONY are provided for 1-87 between the
Bronx Expressway and Macombs Bridge and the traffic data for ROCH are provided
for 1-490 at 1-590.
County-level daily VMT for Monroe County is nearly twice the VMT for Bronx
County. These VMT are in the middle of the range compared to other sites.
18-8
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18.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in New York on sample days, as well as over the course of the year.
18.2.1 Climate Summary
Weather conditions are somewhat variable in New York City as frontal systems
frequently affect the area. Precipitation is spread fairly evenly throughout the year, with
thunderstorms in the summer and fall and more significant rain or snow events in the winter and
spring. The proximity to the Atlantic Ocean offers a moderating influence from cold outbreaks as
well as the summertime heat. The urban heat island effect tends to keep the city warmer than
outlying areas. Both influences result in a relatively small diurnal range of temperatures. In
addition, air sinking down from the mountains to the west can help drive temperatures higher
during warm spells (Bair, 1992).
Rochester is located in western New York and borders Lake Ontario's south side.
Elevation increases significantly from the shore to the southern-most parts of the city, rising over
800 feet. While the lake acts as a moderating influence on the city's temperatures, both in the
summer and the winter, it also plays a major factor in the city's precipitation patterns. Lake
effect snow enhances the area's snowfall totals, although snowfall rates tend to be higher near
Lake Ontario than farther inland. Spring and summer tend to be sunny while cloudy conditions
are prevalent in the fall and winter (Bair, 1992 and NOAA, 2012).
18.2.2 Meteorological Conditions in 2011
Hourly meteorological data from NWS weather stations nearest these sites were retrieved
for 2011 (NCDC, 2011). The closest weather stations are located at Central Park (near MONY)
and Greater Rochester International Airport (near ROCH), WBAN 94728 and 14768,
respectively. Additional information about these weather stations, such as the distance between
the sites and the weather stations, is provided in Table 18-3. These data were used to determine
how meteorological conditions on sample days vary from conditions experienced throughout the
year.
18-9
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Table 18-3. Average Meteorological Conditions near the New York Monitoring Sites
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
New York City, New York - MONY
Central Park
94728
(40.78,73.97)
4.35
miles
199ฐ
(SSW)
Sample
Day
2011
62.6
ฑ4.5
63.1
+ 1.8
55.4
ฑ4.2
56.1
+ 1.7
42.4
ฑ4.9
43.6
+ 2.0
49.4
ฑ4.0
50.2
+ 1.6
64.6
ฑ4.1
65.5
+ 1.7
1015.6
ฑ1.9
1015.5
+ 0.8
5.2
ฑ0.6
5.0
+ 0.2
Rochester, New York - ROCH |
Greater
Rochester Intl.
Airport
14768
(43.12, -77.68)
6.46
miles
240ฐ
(WSW)
Sample
Day
2011
56.4
ฑ5.0
57.8
+ 2.0
48.6
ฑ4.6
49.7
+ 1.9
39.0
ฑ4.4
40.1
+ 1.8
44.0
ฑ4.2
45.1
+ 1.7
72.0
ฑ2.7
71.8
+ 1.1
1015.8
ฑ1.8
1015.3
+ 0.8
7.5
ฑ0.8
7.2
+ 0.3
oo
I
o
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Table 18-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 18-3 is the
95 percent confidence interval for each parameter. Table 18-3 shows that meteorological
conditions near MONY on sample days were representative of average weather conditions
experienced throughout the year. Conditions on sample days near ROCH appear slightly cooler
than conditions experienced throughout the year, although the difference is not statistically
significant.
18.2.3 Back Trajectory Analysis
Figure 18-5 is the composite back trajectory map for days on which samples were
collected at the MONY monitoring site in 2011. Included in Figure 18-5 are four back
trajectories per sample day. Figure 18-6 is the corresponding cluster analysis. Similarly,
Figure 18-7 is the composite back trajectory map for days on which samples were collected at
ROCH and Figure 18-8 is the corresponding cluster analysis. An in-depth description of these
maps and how they were generated is presented in Section 3.5.2.1. For the composite maps, each
line represents the 24-hour trajectory along which a parcel of air traveled toward the monitoring
site on a given sample day and time, based on an initial height of 50 meters AGL. For the cluster
analyses, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the sites in Figures 18-5 through 18-8 represents
100 miles.
18-11
-------
Figure 18-5. 2011 Composite Back Trajectory Map for MONY
Figure 18-6. Back Trajectory Cluster Map for MONY
a HO
18-12
-------
Figure 18-7. 2011 Composite Back Trajectory Map for ROCH
Figure 18-8. Back Trajectory Cluster Map for ROCH
18-13
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Observations from Figures 18-5 and 18-6 for MONY include the following:
Back trajectories originated from a variety of directions at MONY. Back trajectories
most frequently originated to the northwest of MONY.
The 24-hour air shed domain for MONY is similar in size to other NMP sites.
Although the farthest away a back trajectory originated was over Ontario, Canada, or
less than 650 miles away, the average trajectory length was 254 miles and 93 percent
of trajectories originated within 400 miles of the site.
The cluster analysis shows that approximately 20 percent of back trajectories
originated to the northwest of MONY over the Great Lakes and Canada. Twelve
percent originated over the offshore waters of the Mid-Atlantic states. Shorter back
trajectories, generally 200 miles in length or less, originating between these two
cluster trajectories are represented by the short cluster trajectory originating over
southeast Pennsylvania. This cluster trajectory also includes a few longer trajectories
originating over Kentucky, West Virginia, and Virginia. Another 15 percent of back
trajectories originated to the east of MONY over the Atlantic Ocean and 13 percent of
back trajectories originated to the north of the site, primarily over northern New
York, Vermont, and Quebec, Canada.
Observations from Figures 18-7 and 18-8 for ROCH include the following:
Back trajectories originated from a variety of directions at ROCH, although relatively
few originated from the northeast of ROCH.
The 24-hour air shed domain for ROCH was comparable in size to MONY and other
NMP sites. The farthest away a trajectory originated was over western Kentucky, or
approximately 650 miles away. However, the average trajectory length was 252 miles
and 86 percent of back trajectories originated within 400 miles of the site.
The cluster analysis shows that nearly 50 percent of back trajectories originated from
a direction with a westerly component. These back trajectories are represented by
three cluster trajectories in Figure 18-8: 1) longer trajectories originating towards
Lake Michigan (16 percent), 2) longer trajectories originating towards Ohio
(10 percent), and 3) relatively short trajectories (< 200 miles in length) originating
from nearly any direction with a westerly component (25 percent). This third cluster
also includes a few shorter trajectories originating to the south of ROCH.
Nearly one-quarter of back trajectories originated over Ontario and Quebec, Canada.
Nearly 20 percent of back trajectories originated from a direction with an easterly
component. This cluster trajectory also includes the longer trajectories originating
offshore, east of Long Island, New York. Seven percent of trajectories originated to
the south of ROCH over West Virginia, Virginia, and Maryland.
18-14
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18.2.4 Wind Rose Comparison
Hourly surface wind data from the weather stations at Central Park (for MONY) and
Greater Rochester International Airport (for ROCH) were uploaded into a wind rose software
program to produce customized wind roses, as described in Section 3.5.2.2. A wind rose shows
the frequency of wind directions using "petals" positioned around a 16-point compass, and uses
different colors to represent wind speeds.
Figure 18-9 presents a map showing the distance between the NWS station and MONY,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 18-9 also presents three different wind roses for the
MONY monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figure 18-10 presents the distance map and three wind roses
for ROCH.
Observations from Figure 18-9 for MONY include the following:
The weather station at Central Park is located 4.35 miles south-south west of MONY.
The historical wind rose shows that winds from the west and west-northwest account
for greater than 25 percent of wind observations. Winds from the northeast and east-
northeast account for another 15 percent of observations. Calm winds (<2 knots) were
observed for nearly 13 percent of the hourly measurements near MONY.
The 2011 full-year wind rose shares many similarities with the historical wind rose,
such as the prominence of winds from the west. However, the percentage of calm
winds increased for 2011 and the percentages of each of the primary wind directions
decreased slightly.
The sample day wind patterns resemble the wind patterns on the 2011 full-year and
historical wind roses, indicating that wind conditions on sample days were similar to
those experienced throughout 2011 and historically. However, some differences
include an even higher percentage of calm winds (nearly 19 percent) and fewer
observations from the west-southwest.
18-15
-------
Figure 18-9. Wind Roses for the Central Park Weather Station near MONY
Distance between MONY and NWS Station
2001-2010 Historical Wind Rose
WEST!
2011 Wind Rose
Sample Day Wind Rose
WEST
18-16
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Figure 18-10. Wind Roses for the Greater Rochester International Airport Weather Station
near ROCH
Distance between ROCH and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
18-17
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Observations from Figure 18-10 for ROCH include the following:
The Rochester International Airport weather station is located approximately
6.5 miles west-southwest of ROCH, with much of the southern half of the city of
Rochester between them.
The historical wind rose shows that winds from the south-southwest to west were
frequently observed, accounting for nearly 50 percent of the wind observations. Calm
winds were observed for less than nine percent of the hourly measurements near
ROCH, while the strongest winds were most frequently observed with west-
southwesterly and westerly winds.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns for ROCH, although south-southwesterly and west-southwesterly winds were
observed less frequently and a higher percentage of calm winds were observed
(nearly 12 percent).
The sample day wind patterns are similar to those shown on the full-year wind rose,
although the percentages differ somewhat.
18.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the New York monitoring sites
in order to allow analysts and readers to focus on a subset of pollutants through the context of
risk. For each site, each pollutant's preprocessed daily measurement was compared to its
associated risk screening value. If the concentration was greater than the risk screening value,
then the concentration "failed the screen." Pollutants of interest are those for which the
individual pollutant's total failed screens contribute to the top 95 percent of the site's total failed
screens. In addition, if any of the NATTS MQO Core Analytes measured by each monitoring site
did not meet the pollutant of interest criteria based on the preliminary risk-based screening, that
pollutant was added to the list of site-specific pollutants of interest. A more in-depth description
of the risk-based screening process is presented in Section 3.2.
Table 18-4 presents the results of the preliminary risk-based screening process for the
New York monitoring sites. The pollutants that failed at least one screen and contributed to
95 percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. MONY and ROCH
both sampled for hexavalent chromium and PAHs.
18-18
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Table 18-4. Risk-Based Screening Results for the New York Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
New York City, New York - MONY
Naphthalene
Acenaphthene
Fluorene
Fluoranthene
Hexavalent Chromium
Acenaphthylene
Benzo(a)pyrene
0.029
0.011
0.011
0.011
0.000083
0.011
0.00057
Total
60
22
20
8
3
1
1
115
60
60
60
60
60
50
59
409
100.00
36.67
33.33
13.33
5.00
2.00
1.69
28.12
52.17
19.13
17.39
6.96
2.61
0.87
0.87
52.17
71.30
88.70
95.65
98.26
99.13
100.00
Rochester, New York - ROCH
Naphthalene
Acenaphthene
Fluorene
Fluoranthene
0.029
0.011
0.011
0.011
Total
46
22
20
9
97
58
58
58
58
232
79.31
37.93
34.48
15.52
41.81
47.42
22.68
20.62
9.28
47.42
70.10
90.72
100.00
Observations from Table 18-4 include the following:
For MONY, seven pollutants, of which three are NATTS MQO Core Analytes, failed
screens. The risk-based screening process identified four of the pollutants that failed
at least one screen as pollutants of interest. Hexavalent chromium and benzo(a)pyrene
were added as pollutants of interest for MONY because they are NATTS MQO Core
Analytes, even though they did not contribute to 95 percent of the total failed screens.
For ROCH, only four pollutants failed screens. The risk-based screening process
identified all of the pollutants that failed a screen as pollutants of interest. This is
because it took the combined percentages of failed screens to reach the 95 percent
criteria specified in Section 3.2. Hexavalent chromium and benzo(a)pyrene were
added as pollutants of interest for ROCH because they are NATTS MQO Core
Analytes, even though they did not fail any screens. These two pollutants are not
shown in Table 18-4 but are shown in subsequent tables in the sections that follow.
For both sites, naphthalene, acenaphthene, fluorene, and fluoranthene are the four
pollutants that failed the most screens. Aside from naphthalene, these pollutants failed
nearly the same number of screens for these sites.
Naphthalene failed the majority of screens for each site. Naphthalene accounts for
47 percent of failed screens for ROCH and 52 percent of failed screens for MONY.
18-19
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18.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the New York monitoring sites. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest for the New York sites, where the data meet the applicable
criteria. Concentration averages for select pollutants are also presented graphically for each site
to illustrate how the sites' concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at each site. Additional site-
specific statistical summaries for MONY and ROCH are provided in Appendices M and O.
18.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each New York site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the New York
monitoring sites are presented in Table 18-5, where applicable. Note that if a pollutant was not
detected in a given calendar quarter, the quarterly average simply reflects "0" because only zeros
substituted for non-detects were factored into the quarterly average concentration.
18-20
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Table 18-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the New York Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
New York City, New York - MONY
Acenaphthene
Benzo(a)pyrene
Fluoranthene
Fluorene
Hexavalent Chromium
Naphthalene
60/60
59/60
60/60
60/60
60/61
60/60
2.28
ฑ0.39
0.29
ฑ0.06
4.75
ฑ0.75
4.39
ฑ0.65
0.06
ฑ0.01
108.37
ฑ23.45
11.51
ฑ3.31
0.11
ฑ0.03
7.03
ฑ1.89
11.62
ฑ3.36
0.04
ฑ0.01
130.27
ฑ29.50
16.36
ฑ3.22
0.12
ฑ0.06
9.72
ฑ1.95
15.27
ฑ2.87
0.03
ฑ0.01
170.41
ฑ34.78
5.81
ฑ1.49
0.28
ฑ0.08
4.97
ฑ1.27
6.60
ฑ1.42
0.03
ฑ0.01
133.59
ฑ33.66
8.99
ฑ1.80
0.20
ฑ0.04
6.62
ฑ0.89
9.47
ฑ1.55
0.04
ฑ0.01
135.66
ฑ 15.50
Rochester, New York - ROCH
Acenaphthene
Benzo(a)pyrene
Fluoranthene
Fluorene
Hexavalent Chromium
Naphthalene
58/58
42/58
58/58
58/58
41/56
58/58
1.83
ฑ0.69
0.08
ฑ0.06
1.35
ฑ0.42
2.06
ฑ0.55
0.01
ฑ0.01
31.28
ฑ5.74
13.74
ฑ6.91
0.05
ฑ0.03
6.76
ฑ4.56
11.19
ฑ6.11
0.01
ฑ0.01
53.56
ฑ 14.95
27.43
ฑ7.09
0.08
ฑ0.07
12.01
ฑ3.64
21.41
ฑ5.63
0.01
ฑ0.01
103.28
ฑ24.56
5.55
ฑ2.69
0.15
ฑ0.04
2.37
ฑ0.57
4.59
ฑ 1.77
0.01
ฑ0.01
56.69
ฑ 10.08
12.29
ฑ3.55
0.09
ฑ0.03
5.68
ฑ1.76
9.92
ฑ2.81
0.01
ฑ0.01
61.85
ฑ10.12
Observations from Table 18-5 include the following:
The annual average concentration of naphthalene is the highest annual average among
the pollutants of interest for both New York sites. The annual average naphthalene
concentration for MONY is more than twice the annual average for ROCH.
For both sites, the third quarter average concentration of naphthalene is greater than
the other quarterly averages. For ROCH, the eight highest concentrations of
naphthalene (those greater than 100 ng/m3) were all measured in July or August. For
MONY, the maximum naphthalene concentration (330 ng/m3) was measured on
December 5, 2011, although a similar concentration was also measured on
July 20, 2011 (318 ng/m3). The seven concentrations greater than 200 ng/m3
measured at MONY were spread across all four quarters of 2011. This indicates a
relatively high-level of variability within the measurements for MONY. This is also
supported by the relatively large confidence intervals calculated for the quarterly
averages.
18-21
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For both New York sites, concentrations of acenaphthene, fluoranthene, and fluorene
were highest during the warmer months of the year. However, the confidence
intervals calculated for these sites indicate that there is a high level of variability in
the measurements. For example, acenaphthene concentrations for ROCH range from
0.34 ng/m3 to 50.3 ng/m3 with a median concentration of 5.49 ng/m3. The 15 highest
concentrations were measured at ROCH between June and September while 13 of the
15 lowest concentrations were measured between January and March or November
and December.
Conversely, benzo(a)pyrene measurements tended to be measured during the colder
months of the year, particularly for MONY. The single non-detect of benzo(a)pyrene
and the measurements less than 0.1 ng/m3 were measured at MONY between April
and October while all but one of the concentrations greater than 0.25 ng/m3 were
measured between January and March or October and December.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for MONY and
ROCH from those tables include the following:
MONY and ROCH appear in Tables 4-11 seven times, appearing among the top 10
for each PAH with the exception of ROCH's annual average concentration of
naphthalene.
MONY has the second highest annual average concentration of benzo(a)pyrene, the
third highest annual average concentration naphthalene, the fourth highest
concentration of fluorene, and the fifth highest concentration of acenaphthene among
NMP sites sampling PAHs.
ROCH has the second highest annual average concentrations of acenaphthene and
fluorene and the ninth highest annual average concentration of benzo(a)pyrene among
NMP sites sampling PAHs.
MONY has the fourth highest annual average concentration of hexavalent chromium
among sites sampling this pollutant, while the annual average for ROCH ranks lower
(19th).
18.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzo(a)pyrene,
hexavalent chromium, and naphthalene were created for each site. Figures 18-11 through 18-13
overlay the sites' minimum, annual average, and maximum concentrations onto the program-
18-22
-------
level minimum, first quartile, median, average, third quartile, and maximum concentrations, as
described in Section 3.5.3.
Figure 18-11. Program vs. Site-Specific Average Benzo(a)pyrene Concentrations
1 1.25
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 18-12. Program vs. Site-Specific Average Hexavalent Chromium Concentrations
RCO
0.35
0.1
3.15
Concentration (
3.2
3.25
3.3
Program: IstQuartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site: Site Average Site Minimum/Maximum
o
18-23
-------
Figure 18-13. Program vs. Site-Specific Average Naphthalene Concentrations
: ProgramMaxConcentration = 779 ng/m-
i Program Max Concentration = 779 ng/m3
100 150 200 250 300 350 433 450
Concentration (nf/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 18-11 through 18-13 include the following:
Figure 18-11 presents the box plots for benzo(a)pyrene. Note that the program-
level first quartile for this pollutant is zero and is not visible on the box plots. The
box plots show that the annual average concentration for MONY is greater the
annual average concentration for ROCH, although both are greater than the
program-level average concentration (but just barely for ROCH). Although the
range of measurements is slightly greater for MONY than ROCH, the maximum
concentrations of benzo(a)pyrene for both sites are considerably less than the
maximum concentration measured across the program. Several non-detects of
benzo(a)pyrene were measured at ROCH while a single non-detect was measured
at MONY.
Figure 18-12 presents the box plots for hexavalent chromium. The range of
measurements for MONY is roughly twice the range of measurements for ROCH.
The annual average concentration for MONY is greater than the program-level
average concentration and third quartile while the annual average for ROCH is
less than the program-level median concentration. Several non-detects of
hexavalent chromium were measured at ROCH while a single non-detect was
measured at MONY.
Figure 18-13 presents the box plots for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plots
because the scale of the box plots would be too large to readily observe data
points at the lower end of the concentration range. Thus, the scale has been
reduced to 500 ng/m3. Figure 18-13 shows that the annual average naphthalene
concentration for MONY is twice the annual average concentration for ROCH.
While the annual average for ROCH is similar to the program-level median
concentration, the annual average for MONY is greater than the program-level
third quartile. The maximum naphthalene concentration measured at MONY is
twice the maximum concentration measured at ROCH, although both are less than
18-24
-------
the program-level maximum concentration. There were no non-detects of
naphthalene measured at either site. The minimum concentration of naphthalene
measured at MONY (53.9 ng/m3) is the highest minimum concentration among
sites sampling this pollutant.
18.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. Although ROCH has sampled hexavalent chromium under the NMP since 2007,
sampling did not begin until late in the year, which does not allow for the statistical metrics to be
calculated. As a result, a trends analysis was not performed because there would be fewer than
5 years of statistical metrics provided. In addition, sampling for PAHs at ROCH did not begin
until 2008. The MONY site began sampling under the NMP in 2010. Thus, a trends analysis was
not conducted for either site.
18.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each New York monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
18.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the New
York monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3, MRLs
are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
18-25
-------
18.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the New York sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 18-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
Table 18-6. Risk Approximations for the New York Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
New York City, New York - MONY
Acenaphthene
Benzo(a)pyrene
Fluoranthene
Fluorene
Hexavalent Chromium
Naphthalene
0.000088
0.00176
0.000088
0.000088
0.012
0.000034
0.0001
0.003
60/60
59/60
60/60
60/60
60/61
60/60
8.99
ฑ 1.80
0.20
ฑ0.04
6.62
ฑ0.89
9.47
ฑ1.55
0.04
ฑ0.01
135.66
ฑ 15.50
0.79
0.35
0.58
0.83
0.49
4.61
<0.01
0.05
Rochester, New York - ROCH
Acenaphthene
Benzo(a)pyrene
Fluoranthene
Fluorene
Hexavalent Chromium
Naphthalene
0.000088
0.00176
0.000088
0.000088
0.012
0.000034
_
0.0001
0.003
58/58
42/58
58/58
58/58
41/56
58/58
12.29
ฑ3.55
0.09
ฑ0.03
5.68
ฑ1.76
9.92
ฑ2.81
0.01
ฑ0.01
61.85
ฑ10.12
1.08
0.16
0.50
0.87
0.14
2.10
_
0.01
0.02
- = a Cancer URE or Noncancer RfC is not available
18-26
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Observations for the New York sites from Table 18-6 include the following:
Naphthalene has the highest annual average concentration for both sites.
Naphthalene also has the highest cancer risk approximations for both sites
(4.61 in-a-million) for MONY and 2.10 in-a-million for ROCH). For MONY, this is
the only pollutant of interest with a cancer risk approximation greater than
1-in-a-million. For ROCH, acenaphthene also has a cancer risk approximation greater
than 1 in-a-million (1.08 in-a-million).
None of the pollutants of interest for either New York monitoring site have noncancer
hazard approximations greater than 1.0, indicating that no adverse health effects are
expected from these individual pollutants.
18.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 18-7 and 18-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 18-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 18-6. Table 18-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 18-6.
The pollutants listed in Tables 18-7 and 18-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 18.3, both New York sites sampled PAHs and hexavalent chromium. In addition, the
cancer risk and noncancer hazard approximations are limited to those pollutants with enough
data to meet the criteria for annual averages to be calculated. A more in-depth discussion of this
analysis is provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard
approximations, this analysis may help policy-makers prioritize their air monitoring activities.
18-27
-------
Table 18-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the New York Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
New York City, New York (Bronx County) - MONY
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
Naphthalene
1,3 -Butadiene
Dichloromethane
POM, Group 2b
Tetrachloroethylene
POM, Group la
225.51
171.25
104.61
62.07
23.44
22.86
12.53
2.17
1.28
0.93
Benzene
Formaldehyde
Naphthalene
1,3 -Butadiene
Ethylbenzene
POM, Group 3
Hexavalent Chromium, PM
Arsenic, PM
POM, Group 2b
Acetaldehyde
1.76E-03
1.36E-03
7.97E-04
6.86E-04
4.28E-04
3.35E-04
3.18E-04
2.23E-04
1.91E-04
1.37E-04
Naphthalene
Fluorene
Acenaphthene
Fluoranthene
Hexavalent Chromium
Benzo(a)pyrene
4.61
0.83
0.79
0.58
0.49
0.35
Rochester, New York (Monroe County) - ROCH
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Dichloromethane
Naphthalene
POM, Group 2b
Tetrachloroethylene
POM, Group 6
397.57
198.79
197.58
106.73
53.16
47.06
29.93
6.47
1.62
0.67
Benzene
Formaldehyde
1,3 -Butadiene
POM, Group 3
Naphthalene
Hexavalent Chromium, PM
Arsenic, PM
POM, Group 2b
Ethylbenzene
POM, Group 5a
3.10E-03
2.57E-03
1.59E-03
1.36E-03
1.02E-03
7.52E-04
5.79E-04
5.70E-04
4.97E-04
3.51E-04
Naphthalene
Acenaphthene
Fluorene
Fluoranthene
Benzo(a)pyrene
Hexavalent Chromium
2.10
1.08
0.87
0.50
0.16
0.14
oo
to
oo
-------
Table 18-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the New York Monitoring Sites
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations Based
on Annual Average Concentrations
(Site-Specific)
Noncancer
Hazard
Approximation
Pollutant (HQ)
New York City, New York (Bronx County) - MONY
Methanol
Toluene
Xylenes
Benzene
Hexane
Ethylene glycol
Ethylbenzene
Formaldehyde
Acetaldehyde
Hydrochloric acid
808.80
801.90
456.53
225.51
197.82
194.12
171.25
104.61
62.07
55.88
Acrolein
1,3 -Butadiene
Formaldehyde
Naphthalene
Benzene
Acetaldehyde
Xylenes
Cadmium, PM
Arsenic, PM
Hydrochloric acid
999,876.74
11,427.60
10,674.18
7,813.40
7,517.03
6,896.87
4,565.34
3,703.33
3,455.69
2,793.99
Naphthalene 0.05
Hexavalent Chromium <0.01
Rochester, New York (Monroe County) - ROCH
Toluene
Xylenes
Methanol
Benzene
Hexane
Hydrochloric acid
Ethylbenzene
Formaldehyde
Acetaldehyde
Ethylene glycol
944.15
669.05
479.68
397.57
220.52
200.68
198.79
197.58
106.73
104.78
Acrolein
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Hydrochloric acid
Naphthalene
Arsenic, PM
Chlorine
Manganese, PM
641,820.42
26,578.28
20,160.87
13,252.21
11,858.72
10,033.82
9,976.12
8,971.06
7,563.24
7,454.48
Naphthalene 0.02
Hexavalent Chromium <0.01
oo
to
VO
-------
Observations from Table 18-7 include the following:
Benzene, ethylbenzene, and formaldehyde are the highest emitted pollutants with
cancer UREs in Bronx and Monroe Counties.
Benzene and formaldehyde are the pollutants with the highest toxicity-weighted
emissions (of the pollutants with cancer UREs) for both New York counties.
Seven of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Bronx County; six of the highest emitted pollutants also have the
highest toxicity-weighted emissions for Monroe County.
Naphthalene, which has the highest cancer risk approximation for both sites, appears
on both emissions-based lists. Hexavalent chromium appears among the pollutants
with the highest toxicity-weighted emissions for both counties, but is not among the
highest emitted.
Emissions of several POM Groups rank among the highest emitted pollutants as well
as the highest toxicity-weighted emissions for both New York counties. POM, Group
2b appears on both emissions-based lists for both counties and includes several PAHs
sampled for at these sites, including acenaphthene, fluoranthene, and fluorene. POM,
Group 5a has one of the highest toxicity-weighted emissions for Monroe County and
includes benzo(a)pyrene. POM, Group 6, which ranks 10th for quntity emitted for
Monroe County, includes benzo(a)anthracene, benzo(b)fluoranthene,
benzo(k)fluoranthene, and indeno(l,2,3-cd)pyrene.
Observations from Table 18-8 include the following:
Methanol, toluene, and xylenes are the highest emitted pollutants with noncancer
RfCs in both Bronx and Monroe Counties, although not necessarily in that order.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, 1,3-butadiene, and formaldehyde for both counties.
Five of the highest emitted pollutants in Bronx County are also among the pollutants
with the highest toxicity-weighted emissions; four of the highest emitted pollutants in
Monroe County are also among the pollutants with the highest toxicity-weighted
emissions.
Naphthalene is among the pollutants with the highest toxicity-weighted emissions for
each county, but is not among the highest emitted pollutants with a noncancer toxicity
factor for either county. Hexavalent chromium does not appear on either emissions-
based list for either New York county. None of the other pollutants of interest for
either site have noncancer RfCs.
18-30
-------
18.6 Summary of the 2011 Monitoring Data for MONY and ROCH
Results from several of the data treatments described in this section include the
following:
ปซป Seven pollutants failed screens for MONY while four pollutants failed screens for
ROCH. The same four pollutants were identified as pollutants of interest via the risk-
based screening process for MONY and ROCH.
ปซป Naphthalene had the highest annual average concentration among the pollutants of
interest for both sites.
ปซป For both sites, concentrations ofacenaphthene, fluoranthene, andfluorene were
highest during the warmer months of the year while concentrations of benzo(a)pyrene
were highest during the colder months of the year.
18-31
-------
19.0 Sites in Oklahoma
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the UATMP sites in Oklahoma, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
19.1 Site Characterization
This section characterizes the Oklahoma monitoring sites by providing geographical and
physical information about the locations of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
Two Oklahoma sites (TOOK and TMOK) are located in the Tulsa, Oklahoma MSA.
Another site, PROK, is located east of the Tulsa area in Pry or Creek, Oklahoma. There are also
two sites in the Oklahoma City, Oklahoma MSA; one site is located in Oklahoma City (OCOK)
and another is located just outside Oklahoma City in Midwest City (MWOK).
Figures 19-1 and 19-2 are composite satellite images retrieved from ArcGIS Explorer
showing the Tulsa monitoring sites in their urban locations. Figure 19-3 identifies nearby point
source emissions locations by source category, as reported in the 2008 NEI for point sources.
Note that only sources within 10 miles of the sites are included in the facility counts provided in
Figure 19-3. A 10-mile boundary was chosen to give the reader an indication of which emissions
sources and emissions source categories could potentially have a direct effect on the air quality at
the monitoring sites. Further, this boundary provides both the proximity of emissions sources to
the monitoring sites as well as the quantity of such sources within a given distance of the sites.
Sources outside the 10-mile radii are still visible on the map, but have been grayed out in order
to show emissions sources just outside the boundary. Figures 19-4 through 19-8 are the
composite satellite maps and emissions source maps for the Pry or Creek and Oklahoma City
sites. Table 19-1 provides supplemental geographical information such as land use, location
setting, and locational coordinates.
19-1
-------
Figure 19-1. Tulsa, Oklahoma (TOOK) Monitoring Site
to
-------
Figure 19-2. Tulsa, Oklahoma (TMOK) Monitoring Site
-------
Figure 19-3. NEI Point Sources Located Within 10 Miles of TMOK and TOOK
Legend
@ TMOK UATMP site ฎ TOOK UATMP site
Source Category Group (No. of Facilities)
J" Aerospace/Aircraft Manufacturing (1)
-fr1 Aircraft Operations (14)
W Automobile/Truck Manufacturing (1)
* Electricity Generation via Combustion (2)
W Glass Manufacturing (2)
ee-O'trw es-sso-w
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest
10 mile radius
County boundary
? Miscellaneous Commercial/Industrial (1)
H Municipal Waste Combustor (1)
* Petroleum Refinery (2)
7 Portland Cement Manufacturing (1)
V Steel Mill (1)
* Transportation and Marketing of Petroleum Products (1)
19-4
-------
Figure 19-4. Pryor Creek, Oklahoma (PROK) Monitoring Site
-------
Figure 19-5. NEI Point Sources Located Within 10 Miles of PROK
Legend
ฉ PROK UATMP site
fl6"25'0"W fl5-2ff(rw 95115'0"W 95 1 ffO'W 95' 5'CTW
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
0 10 mile radius
County boundary
Source Category Group (No. of Facilities)
41 Aircraft Operations (5)
c Chemical Manufacturing (1)
* Electricity Generation via Combustion (2)
F Food Processing/Agriculture (1)
7 Portland Cement Manufacturing (1)
19-6
-------
Figure 19-6. Midwest City, Oklahoma (MWOK) Monitoring Site
V ป >^ -y I 'LfjAm
u '//
-------
Figure 19-7. Oklahoma City, Oklahoma (OCOK) Monitoring Site
oo
.A
-------
Figure 19-8. NEI Point Sources Located Within 10 Miles of MWOK and OCOK
97-45'0-W 97"40'0*W 97'35'Q*W S7i3C<10"W S/'JS'O'W 97'20'0"W
Note: Due to facility density and collocation. th9 total facilities
Legend
Sfe MWOK UATMP site
displayed may not represent all facilities within the area of interest.
OCOK UATMP site 10 mile radius | | County boundary
Source Category Group (No. of Facilities)
41 Aircraft Operations (19)
IB Bakery (1)
F Food Processing/Agriculture (1)
A Military Base/National Security Facility (1)
Oil and/or Gas Production (2)
P Printing/Publishing (1)
19-9
-------
Table 19-1. Geographical Information for the Oklahoma Monitoring Sites
Site
Code
TOOK
TMOK
PROK
MWOK
OCOK
AQS Code
40-143-0235
40-143-1127
40-097-0187
40-109-0041
40-109-1037
Location
Tulsa
Tulsa
Pryor
Creek
Midwest
City
Oklahoma
City
County
Tulsa
Tulsa
Mayes
Oklahoma
Oklahoma
Micro- or
Metropolitan
Statistical Area
Tulsa, OK MSA
Tulsa, OK MSA
Not in an MSA
Oklahoma City,
OK MSA
Oklahoma City,
OK MSA
Latitude
and
Longitude
36.126945,
-95.998941
36.204902,
-95.976537
36.292941,
-95.303409
35.437641,
-97.387254
35.614131,
-97.475083
Land Use
Industrial
Residential
Industrial
Commercial
Residential
Location
Setting
Urban/City
Center
Urban/City
Center
Suburban
Urban/City
Center
Suburban
Additional Ambient Monitoring Information1
SO2 and H2S.
CO, SO2, NOy, NO, NO2, NOX, O3, Meteorological
parameters, PM10, PM Coarse, PM25, and PM25
Speciation.
None.
None.
SO2, NO, NO2, NOX, O3, Meteorological parameters,
PMio, PM2 5, and PM2 5 Speciation.
Data for additional pollutants are reported to AQS for these sites (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this report
VO
o
-------
TOOK is located in West Tulsa, on the southwest side of the Arkansas River. The site is
located in the parking lot of the Public Works building. The monitoring site is positioned
between the Arkansas River and 1-244, which runs parallel to Southwest Boulevard. The
surrounding area is primarily industrial. As shown in Figure 19-1, an oil refinery is located just
south of the site. Another refinery is located to the northwest of the site, on the other side of
1-244. A rail yard is located on the opposite side of 1-244.
TMOK is located in north Tulsa on the property of Fire Station Number 24. As shown in
Figure 19-2, the intersection of North Peoria Avenue (Highway 11) and East 36th Street North
lies just to the northeast of the site. The surrounding area is primarily residential, with wooded
areas just to the east, an early childhood education facility and an elementary school to the south,
and a park to the west.
Figure 19-3 shows that the Tulsa sites are located approximately 5 miles apart, with
TMOK to the north and TOOK to the south. Most of the emissions sources are clustered around
TOOK, while there are no point sources within a couple miles of TMOK. The source category
with the greatest number of sources surrounding the Tulsa sites is the aircraft operations source
category, which includes airports as well as small runways, heliports, or landing pads. Point
sources closest to TOOK include petroleum refineries, a municipal waste combustor, and a
facility generating electricity via combustion.
PROK is located on the eastern edge of the town of Pry or Creek, on the property of Pry or
Creek High School. Residential areas are located to the northwest, west, and south of the site,
while agricultural areas are located to the east, as shown in Figure 19-4. The monitoring site is
located due north (and downwind) of an industrial park located a few miles to the south.
Figure 19-5 shows that there are relatively few emissions sources surrounding PROK and that
the aircraft operations source category has the greatest number of emissions sources near the site.
An aircraft operations facility is located a quarter mile north of PROK but is located under the
site symbol in Figure 19-5. The aforementioned industrial park is represented in Figure 19-5 by
the chemical manufacturing and food processing/agriculture facilities located to the south of
PROK.
19-11
-------
The MWOK monitoring site is located in Midwest City, southeast of Oklahoma City. The
site is located in a commercial area on South Midwest Boulevard just north of 1-40. This site is
located at a school enrollment center just north of Tinker Air Force Base, the northern portion of
which can be seen just south of 1-40 in Figure 19-6. Residential areas are located to the northwest
and north, while an extension of Tinker AFB is located to the east.
OCOK is located in northern Oklahoma City, on the property of Oklahoma Christian
University of Science and Arts. The site is located in the northwest corner of the University, near
the athletic fields. The areas surrounding the university are primarily residential. Heavily
traveled roadways such as 1-35 and 1-44 to the east and John Kilpatrick Turnpike to the south are
within a few miles of the site, although outside the boundaries of Figure 19-7.
Figure 19-8 shows that MWOK and OCOK are approximately 13 miles apart and that
most of the point sources located within 10 miles of them are located between the sites in the
center of Oklahoma City (west and northwest of MWOK and south of OCOK). The source
category with the greatest number of sources surrounding the two sites is the aircraft operations
source category. The point source closest to MWOK is the military base; the source closest to
OCOK is a heliport.
Table 19-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Oklahoma monitoring sites. Table 19-2 includes county-level
population and vehicle registration information. Table 19-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 19-2 also
contains traffic volume information for each site. Finally, Table 19-2 presents the county-level
daily VMT for Tulsa, Mayes, and Oklahoma Counties.
19-12
-------
Table 19-2. Population, Motor Vehicle, and Traffic Information for the Oklahoma
Monitoring Sites
Site
TOOK
TMOK
PROK
MWOK
OCOK
Estimated
County
Population1
610,599
41,389
732,371
County-level
Vehicle
Registration2
603,926
39,968
832,160
Vehicles per
Person
(Registration:
Population)
0.99
0.97
1.14
Population
within 10
miles3
453,918
327,223
30,326
376,168
378,154
Estimated
10-mile
Vehicle
Ownership
448,957
323,647
29,285
427,423
429,679
Annual
Average
Daily
Traffic4
63,000
12,600
15,100
40,900
40,900
County-
level Daily
VMT5
20,348,926
1,656,458
27,190,328
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Oklahoma Tax Commission (OKTC, 2011)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the Oklahoma DOT (OK DOT, 2011)
5County-level VMT reflects 2011 data from the Oklahoma DOT (OK DOT, 2012)
Observations from Table 19-2 include the following:
The Mayes County population is significantly lower than the populations for Tulsa
and Oklahoma County. This is also true of the 10-mile populations. Compared to
other NMP monitoring sites, the Tulsa and Oklahoma City populations are in the
middle of the range, while Pry or Creek's population is on the low end.
The Mayes County vehicle registration is also significantly lower than vehicle
registration for Tulsa and Oklahoma Counties. Similar observations can be made for
the 10-mile vehicle registration estimates. These observations are expected given the
rural nature of the area surrounding PROK compared to the urban location of the
Tulsa and Oklahoma City sites. Compared to other NMP monitoring sites, the vehicle
ownership estimates follow a similar pattern as the populations.
The county-level registration-to-population ratios range from 0.97 vehicles per person
for PROK to 1.14 vehicles per person for MWOK and OCOK.
The traffic volume passing the TMOK site is the lowest among the Oklahoma
monitoring sites and is similar to the traffic passing the PROK site, while the traffic
passing by TOOK is the highest of the five sites. The traffic data for TMOK and
PROK are in the bottom third among NMP sites while the traffic for TOOK is in the
middle of the range. Although the traffic counts are the same for MWOK and OCOK,
the counts represent different locations. The following list provides the roadways or
intersections from which the traffic data were obtained: TOOK -1-244, north of the
split with US-75; TMOK - East 36th Street North near North Peoria Avenue; PROK -
Highway 69, south of Graham Avenue (Highway 20); MWOK -1-40, west of Tinker
Air Force Base; OCOK - Highway 77 north of Highway 44 (before the bend at West
33rd Street).
19-13
-------
County-level VMT is greatest for Oklahoma County and ranks 11th compared to other
NMP sites. VMT is the smallest for Mayes County and is among the smallest VMT
compared to other sites.
19.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Oklahoma on sample days, as well as over the course of the year.
19.2.1 Climate Summary
Tulsa is located in northeast Oklahoma, just southeast of the Osage Indian Reservation,
and along the Arkansas River. Pry or Creek is also in northeast Oklahoma, approximately
30 miles east of Tulsa. Oklahoma City is located in the center of the state. These areas are
characterized by a continental climate, with very warm summers and cool winters. Precipitation
is generally concentrated in the spring and summer months, with spring as the wettest season,
although precipitation amounts generally decrease across the state from east to west. Spring and
summer precipitation usually results from showers and thunderstorms, while fall and winter
precipitation accompanies frontal systems. A southerly wind prevails for much of the year,
bringing warm, moist air northward from the Gulf of Mexico. Oklahoma is part of "Tornado
Alley," where severe thunderstorms capable of producing strong winds, hail, and tornadoes
occur more frequently than other areas around the county; tornadoes are more prevalent here
than any other region in the U.S. (Bair, 1992; NCDC, 2013; and NOAA, 2013b).
19.2.2 Meteorological Conditions in 2011
Hourly meteorological data from NWS weather stations nearest these sites were retrieved
for 2011 (NCDC, 2011). The closest weather stations to the Tulsa sites are located at Richard
Lloyd Jones Jr. Airport (near TOOK) and Tulsa International Airport (near TMOK), WBAN
53908 and 13968, respectively. The closest weather station to the Pryor Creek site is located at
Claremore Regional Airport, WBAN 53940. The two closest weather stations to the Oklahoma
City sites are located at Tinker Air Force Base Airport (near MWOK) and Wiley Post Airport
(near OCOK), WBAN 13919 and 03954, respectively. Additional information about these
weather stations, such as the distance between the sites and the weather stations, is provided in
Table 19-3. These data were used to determine how meteorological conditions on sample days
vary from conditions experienced throughout the year.
19-14
-------
Table 19-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 19-3 is the
95 percent confidence interval for each parameter. As shown in Table 19-3, average
meteorological conditions on sample days were representative of average weather conditions
throughout the year for most of the Oklahoma monitoring sites. The differences are greatest for
MWOK, where sample days appear slightly warmer than conditions experienced throughout the
year, but the difference is not statistically significant. Sampling was discontinued at MWOK at
the end of November 2011 in order to move the instruments to a new sampling location, which
likely explains these differences.
19.2.3 Back Trajectory Analysis
Figure 19-9 is the composite back trajectory map for days on which samples were
collected at the TOOK monitoring site in 2011. Included in Figure 19-9 are four back trajectories
per sample day. Figure 19-10 is the corresponding cluster analysis. Similarly, Figures 19-11
through 19-18 are the composite back trajectory maps for days on which samples were collected
at the remaining Oklahoma sites and the corresponding cluster analyses. An in-depth description
of these maps and how they were generated is presented in Section 3.5.2.1. For the composite
maps, each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analyses, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the sites in Figures 19-9 through 19-18 represents
100 miles.
19-15
-------
Table 19-3. Average Meteorological Conditions near the Oklahoma Monitoring Sites
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Tulsa, Oklahoma - TOOK
Richard Lloyd
Jones Jr.
Airport
53908
(36.04, -95.98)
6.12
miles
172ฐ
(S)
Sample
Day
2011
74.5
ฑ5.3
74.1
+ 2.2
62.7
ฑ5.2
62.1
+ 2.1
47.0
ฑ4.5
46.8
+ 1.8
53.9
ฑ4.3
53.6
+ 1.7
60.8
ฑ2.9
61.6
+ 1.3
1015.8
ฑ2.1
1015.8
ฑ0.7
6.2
ฑ0.9
5.6
+ 0.3
Tulsa, Oklahoma - TMOK
Tulsa
International
Airport
13968
(36.20, -95.89)
4.81
miles
96ฐ
(E)
Sample
Day
2011
73.4
ฑ5.4
73.3
+ 2.2
62.7
ฑ5.2
62.5
+ 2.1
46.1
ฑ4.3
46.0
+ 1.8
53.4
ฑ4.2
53.3
+ 1.7
58.8
ฑ3.1
59.2
+ 1.4
1014.7
ฑ2.1
1014.6
+ 0.7
9.1
ฑ1.1
8.4
+ 0.4
Pryor Creek, Oklahoma - PROK
Claremore
Regional
Airport
53940
(36.29, -95.47)
8.66
miles
270ฐ
(W)
Sample
Day
2011
70.4
ฑ5.2
71.0
+ 2.1
58.8
ฑ5.1
59.7
+ 2.0
45.9
ฑ4.3
46.9
+ 1.8
51.6
ฑ4.3
52.6
+ 1.7
66.4
ฑ2.9
66.7
+ 1.3
NA
NA
7.5
ฑ1.0
6.8
+ 0.4
Midwest City, Oklahoma - MWOK
Tinker
AFB/Airport
13919
(35.42, -97.39)
1.57
miles
178ฐ
(S)
Sample
Day
2011
76.3
ฑ5.5
74.6
+ 2.2
64.4
ฑ5.3
63.0
+ 2.1
47.0
ฑ4.5
45.8
+ 1.8
54.6
ฑ4.3
53.5
+ 1.7
57.8
ฑ3.6
58.5
+ 1.6
1013.7
ฑ2.0
1014.6
ฑ0.8
11.3
ฑ1.2
10.3
+ 0.4
Oklahoma City, Oklahoma - OCOK
Wiley Post
Airport
03954
(35.53, -97.65)
10.68
miles
240ฐ
(WSW)
Sample
Day
2011
74.5
ฑ5.6
74.5
+ 2.2
63.1
ฑ5.4
63.1
+ 2.2
44.5
ฑ4.3
44.4
+ 1.7
52.8
ฑ4.2
52.8
+ 1.7
55.7
ฑ3.4
55.8
+ 1.6
1014.4
ฑ2.2
1014.3
ฑ0.8
11.9
ฑ1.3
10.9
+ 0.4
VO
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
NA = Sea level pressure was not recorded at the Claremore Regional Airport
-------
Figure 19-9. 2011 Composite Back Trajectory Map for TOOK
Figure 19-10. Back Trajectory Cluster Map for TOOK
19-17
-------
Figure 19-11. 2011 Composite Back Trajectory Map for TMOK
Figure 19-12. Back Trajectory Cluster Map for TMOK
19-18
-------
Figure 19-13. 2011 Composite Back Trajectory Map for PROK
Figure 19-14. Back Trajectory Cluster Map for PROK
19-19
-------
Figure 19-15. 2011 Composite Back Trajectory Map for MWOK
Figure 19-16. Back Trajectory Cluster Map for MWOK
19-20
-------
Figure 19-17. 2011 Composite Back Trajectory Map for OCOK
Figure 19-18. Back Trajectory Cluster Map for OCOK
19-21
-------
Observations from Figures 19-9 through 19-18 include the following:
The back trajectory maps for the Tulsa sites, the Pry or Creek site, and the Oklahoma
City sites are similar to each other in back trajectory distribution. This is somewhat
expected, given their relatively close proximity to each other and the similarity in
sample days, although not all sites sampled on the exact same days over the period.
The air shed domains for the Oklahoma City and Midwest City sites were among the
largest compared to other NMP sites, ranking second and third, respectively, based on
average trajectory length. The farthest away a back trajectory originated was over
northern Minnesota, or approximately 800 miles away, with an average trajectory
length of nearly 300 miles. The air shed domains for TOOK, TMOK, and PROK
round out the top 10 sites based on air shed domain size compared to other NMP
sites. For these sites, the farthest away a back trajectory originated was over north-
central South Dakota, or greater than 650 miles away. The average trajectory length
for these sites ranged from 268 miles (PROK) to 277 miles (TOOK).
Each of the sites exhibits a strong tendency for back trajectories to originate from the
south-southeast to south-southwest of the sites and from the northwest to northeast of
the sites.
For the Tulsa and Pry or Creek sites, greater than 60 percent of back trajectories
originated from the southeast to southwest, generally over eastern Texas. Another
one-third of trajectories originated generally from the west to northwest to north of
the sites, but of varying lengths. The remaining back trajectories originated from the
northeast to east, generally over the state of Missouri.
The cluster analysis maps for the Oklahoma City and Midwest City sites are similar
to each other and to the cluster maps for the Tulsa and Pry or Creeks sites in cluster
distribution patterns. One difference between the cluster maps for OCOK and
MWOK is the number of cluster trajectories. Back trajectories originating over the
panhandles of Texas and Oklahoma are represented by a single cluster for OCOK
(12 percent). For MWOK, the back trajectories originating over the panhandle of
Texas are represented by their own cluster trajectory (13 percent), while those
originating over the panhandle of Oklahoma are included with shorter, northward-
originating trajectories as well as others originating within the state of Oklahoma.
These are represented by the cluster trajectory originating just north of the Kansas-
Oklahoma border (12 percent).
19-22
-------
19.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations at Richard Lloyd Jones Junior
Airport (for TOOK), Tulsa International Airport (for TMOK), Claremore Regional Airport (for
PROK), Wiley Post Airport (for OCOK), and Tinker Air Force Base (for MWOK) were
uploaded into a wind rose software program to produce customized wind roses, as described in
Section 3.5.2.2. A wind rose shows the frequency of wind directions using "petals" positioned
around a 16-point compass, and uses different colors to represent wind speeds.
Figure 19-19 presents a map showing the distance between the NWS station and TOOK,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 19-19 also presents three different wind roses for the
TOOK monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figures 19-20 through 19-23 present the distance map and
wind roses for the remaining Oklahoma sites.
19-23
-------
Figure 19-19. Wind Roses for the Richard Lloyd Jones Jr. Airport Weather Station near
TOOK
Distance between TOOK and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
35%
*"ปi 28%
" "'-, 21%
1 4%
7% '; : :
WIND SPEED
(Knot!)
n ป=
^| 17 21
^| 11 - 17
^| 7- 11
n 4.7
Hi 2- 4
Calms: 25.07%
Sample Day Wind Rose
19-24
-------
Figure 19-20. Wind Roses for the Tulsa International Airport Weather Station near
TMOK
Distance between TMOK and NWS Station
2001-2010 Historical Wind Rose
i * *
\>\l I
IWEST
30%
*"*,, 24%
"~N 18%
1 2%
s% '; ': :
WIND SPEED
(Knots)
o *=
^| 17 21
^| 11 - 17
^| 7- 11
n 4-7
2011 Wind Rose
Sample Day Wind Rose
19-25
-------
Figure 19-21. Wind Roses for the Claremore Regional Airport Weather Station near
PROK
Distance between PROK and NWS Station
2003-2010 Historical Wind Rose
WIND SPEED
(Knots)
O *=
^| 17 21
^| 11 - 17
^| 7- 11
CH 4-7
! 2- 4
Calms: 15.89%
2011 Wind Rose
Sample Day Wind Rose
'WEST ;
25%
"**, 20%
1 5%
1 0%
VjlND SPEED
(Knots)
^| 17 - 21
I 11 17
JH 7- 11
| | 4- 7
Calms: 19.89ฐ4
19-26
-------
Figure 19-22. Wind Roses for the Tinker Air Force Base Airport Weather Station near
MWOK
Distance between MWOK and NWS Station
2006-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
19-27
-------
Figure 19-23. Wind Roses for the Wiley Post Airport Weather Station near OCOK
Distance between OCOK and NWS Station
2001-2010 Historical Wind Rose
J*^5 1 "HE VILLAGE
^""t,^^ W w Wiซltiปป !ป*
.,j''''., a 4*cซa.
2011 Wind Rose
Sample Day Wind Rose
/VEST
WIND SPEED
(Knots)
n -22
H 17 21
^| 11 17
^| 7- 11
n 4-7
^| 2- 4
Calms: 3.21 %
19-28
-------
Observations from Figures 19-19 through 19-23 include the following:
The distance maps show that the distances between the sites and the weather stations
varies from 1.6 miles between Tinker Air Force Base and MWOK to 10.7 miles
between OCOK and the Wiley Post Airport.
Even though the historical data are from five different weather stations, the wind
patterns shown on wind roses for the Oklahoma sites are similar to each other. Each
of the historical wind roses shows that southerly winds prevailed near each Oklahoma
monitoring site, accounting for roughly one-fifth to one-quarter of the observations
among the historical time periods. The historical wind roses varied in the percentage
of calm winds (<2 knots) observed, ranging from as little as three percent at the
Tinker Air Force Base (MWOK) to as high as 25 percent at the Richard Lloyd Jones
Jr. Airport (TOOK). Further, calms winds, winds from the south-southeast to south-
southwest, and winds from the north-northwest to north-northeast account for the
majority of wind observations while winds from the west or east were rarely observed
near each site.
For TOOK, the 2011 wind patterns are similar to the historical wind patterns, as are
the sample day wind patterns, although a higher percentage of southerly winds were
observed on sample days. These similarities indicate that conditions on sample days
were representative of those experienced over the entire year and historically.
For TMOK, the 2011 wind patterns resemble the historical wind patterns, although
there was a slightly higher percentage of southeasterly and south-southeasterly winds
observed in 2011. The sample day wind patterns are similar to the full-year wind
patterns, although a higher percentage of southerly winds were observed on sample
days. These similarities indicate that conditions on sample days were representative
of conditions experienced throughout the year and historically.
For PROK, the historical wind rose includes eight years worth of data. The 2011 wind
patterns are nearly identical to the historical wind patterns. The one difference is the
slightly reduced number of south-southwesterly wind observations for 2011, which
are reflected in the higher calm rate. The sample day wind rose for PROK is similar
to the historical and full-year wind roses, although a higher percentage of southerly
winds were observed on sample days. These similarities indicate that conditions on
sample days were representative of conditions experienced throughout the year and
historically.
For MWOK, the historical wind rose includes only five years worth of data. The 2011
wind patterns resemble the historical wind patterns, although there were slightly
fewer south-southwesterly wind observations and slightly more northwesterly winds
observations in 2011. The sample day wind patterns resemble the historical and the
full-year wind patterns roses, although there are a few subtle differences. The sample
day wind rose has a higher percentage of southerly winds, as well as a higher
percentage of south-southeasterly winds. The calm rate for sample days
(1.36 percent) is roughly half the calm rate on the full-year wind rose (2.96 percent),
although both are low percentages.
19-29
-------
For OCOK, the wind patterns shown on the 2011 wind rose are nearly identical to the
historical wind patterns. The sample day wind rose for OCOK is similar to both the
historical and full-year wind roses, but there was a slightly higher percentage of
southerly winds observed in 2011 and a slightly reduced calm rate. However, the
similarities indicate that conditions on sample days were representative of those
experienced over the entire year and historically.
19.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Oklahoma monitoring sites
in order to allow analysts and readers to focus on a subset of pollutants through the context of
risk. For each site, each pollutant's preprocessed daily measurement was compared to its
associated risk screening value. If the concentration was greater than the risk screening value,
then the concentration "failed the screen." Pollutants of interest are those for which the
individual pollutant's total failed screens contribute to the top 95 percent of the site's total failed
screens. In addition, if any of the NATTS MQO Core Analytes measured by each monitoring site
did not meet the pollutant of interest criteria based on the preliminary risk-based screening, that
pollutant was added to the list of site-specific pollutants of interest. A more in-depth description
of the risk-based screening process is presented in Section 3.2.
Table 19-4 presents the results of the preliminary risk-based screening process for each
Oklahoma monitoring site. The pollutants that failed at least one screen and contributed to 95
percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. The five Oklahoma
sites sampled for VOCs, carbonyl compounds, and metals (TSP).
19-30
-------
Table 19-4. Risk-Based Screening Results for the Oklahoma Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Tulsa, Oklahoma - TOOK
Benzene
Carbon Tetrachloride
Acetaldehyde
Formaldehyde
Manganese (TSP)
Arsenic (TSP)
1,3-Butadiene
p-Dichlorobenzene
Ethylbenzene
Nickel (TSP)
Propionaldehyde
Cadmium (TSP)
1 ,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
Acrylonitrile
1 ,2-Dibromoethane
Cobalt (TSP)
Lead (TSP)
1 , 1 ,2,2-Tetrachloroethane
Xylenes
0.13
0.17
0.45
0.077
0.005
0.00023
0.03
0.091
0.4
0.0021
0.8
0.00056
0.038
0.045
0.015
0.0017
0.01
0.015
0.017
10
Total
57
57
56
56
56
55
51
43
39
18
7
6
6
5
3
2
1
1
1
1
521
57
57
56
56
56
56
52
51
57
56
56
56
6
5
3
2
56
56
1
57
852
100.00
100.00
100.00
100.00
100.00
98.21
98.08
84.31
68.42
32.14
12.50
10.71
100.00
100.00
100.00
100.00
1.79
1.79
100.00
1.75
61.15
10.94
10.94
10.75
10.75
10.75
10.56
9.79
8.25
7.49
3.45
1.34
1.15
1.15
0.96
0.58
0.38
0.19
0.19
0.19
0.19
10.94
21.88
32.63
43.38
54.13
64.68
74.47
82.73
90.21
93.67
95.01
96.16
97.31
98.27
98.85
99.23
99.42
99.62
99.81
100.00
Tulsa, Oklahoma - TMOK
Acetaldehyde
Formaldehyde
Benzene
Carbon Tetrachloride
Manganese (TSP)
Arsenic (TSP)
1,3-Butadiene
Ethylbenzene
ฃ>-Dichlorobenzene
Acrylonitrile
1 ,2-Dichloroethane
Nickel (TSP)
Propionaldehyde
Hexachloro- 1 ,3 -butadiene
Cadmium (TSP)
0.45
0.077
0.13
0.17
0.005
0.00023
0.03
0.4
0.091
0.015
0.038
0.0021
0.8
0.045
0.00056
61
61
60
60
58
56
49
36
24
10
10
10
8
o
J
1
61
61
60
60
58
58
51
60
47
10
10
58
61
3
58
100.00
100.00
100.00
100.00
100.00
96.55
96.08
60.00
51.06
100.00
100.00
17.24
13.11
100.00
1.72
11.94
11.94
11.74
11.74
11.35
10.96
9.59
7.05
4.70
1.96
1.96
1.96
1.57
0.59
0.20
11.94
23.87
35.62
47.36
58.71
69.67
79.26
86.30
91.00
92.95
94.91
96.87
98.43
99.02
99.22
19-31
-------
Table 19-4. Risk-Based Screening Results for the Oklahoma Monitoring Sites (Continued)
Pollutant
Chloromethylbenzene
Cobalt (TSP)
1 ,2-Dibromoethane
Lead (TSP)
Screening
Value
(Ug/m3)
0.02
0.01
0.0017
0.015
Total
#of
Failed
Screens
1
1
1
1
511
#of
Measured
Detections
1
58
1
58
834
%of
Screens
Failed
100.00
1.72
100.00
1.72
61.27
% of Total
Failures
0.20
0.20
0.20
0.20
Cumulative
%
Contribution
99.41
99.61
99.80
100.00
Pryor Creek, Oklahoma - PROK
Acetaldehyde
Formaldehyde
Benzene
Carbon Tetrachloride
Arsenic (TSP)
Manganese (TSP)
p-Dichlorobenzene
1,3-Butadiene
1 ,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
Acrylonitrile
1, 1,2,2-Tetrachloroethane
Bromomethane
Ethylbenzene
Xylenes
0.45
0.077
0.13
0.17
0.00023
0.005
0.091
0.03
0.038
0.045
0.015
0.017
0.5
0.4
10
Total
58
58
56
56
51
48
36
30
17
4
3
2
1
1
1
422
58
58
56
56
56
56
47
33
17
4
3
2
34
56
56
592
100.00
100.00
100.00
100.00
91.07
85.71
76.60
90.91
100.00
100.00
100.00
100.00
2.94
1.79
1.79
71.28
13.74
13.74
13.27
13.27
12.09
11.37
8.53
7.11
4.03
0.95
0.71
0.47
0.24
0.24
0.24
13.74
27.49
40.76
54.03
66.11
77.49
86.02
93.13
97.16
98.10
98.82
99.29
99.53
99.76
100.00
Midwest City, Oklahoma - MWOK
Acetaldehyde
Benzene
Carbon Tetrachloride
Formaldehyde
Manganese (TSP)
Arsenic (TSP)
1,3-Butadiene
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Acrylonitrile
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Nickel (TSP)
1 ,2-Dibromoethane
cis- 1 , 3 -D ichloropropene
0.45
0.13
0.17
0.077
0.005
0.00023
0.03
0.091
0.038
0.015
0.4
0.045
0.0021
0.0017
0.25
56
56
56
56
52
48
36
26
9
5
5
4
4
1
1
56
56
56
56
56
56
40
50
9
5
56
4
56
1
1
100.00
100.00
100.00
100.00
92.86
85.71
90.00
52.00
100.00
100.00
8.93
100.00
7.14
100.00
100.00
13.43
13.43
13.43
13.43
12.47
11.51
8.63
6.24
2.16
1.20
1.20
0.96
0.96
0.24
0.24
13.43
26.86
40.29
53.72
66.19
77.70
86.33
92.57
94.72
95.92
97.12
98.08
99.04
99.28
99.52
19-32
-------
Table 19-4. Risk-Based Screening Results for the Oklahoma Monitoring Sites (Continued)
Pollutant
trans- 1 , 3 -Dichloropropene
1 , 1 ,2,2-Tetrachloroethane
Screening
Value
(Ug/m3)
0.25
0.017
Total
#of
Failed
Screens
1
1
417
#of
Measured
Detections
1
1
560
%of
Screens
Failed
100.00
100.00
74.46
% of Total
Failures
0.24
0.24
Cumulative
%
Contribution
99.76
100.00
Oklahoma City, Oklahoma - OCOK
Benzene
Acetaldehyde
Formaldehyde
Carbon Tetrachloride
Arsenic (TSP)
Manganese (TSP)
1,3-Butadiene
p-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Acrylonitrile
Propionaldehyde
Hexachloro- 1 ,3 -butadiene
Cadmium (TSP)
1, 1,2,2-Tetrachloroethane
1 ,2-Dibromoethane
0.13
0.45
0.077
0.17
0.00023
0.005
0.03
0.091
0.038
0.4
0.015
0.8
0.045
0.00056
0.017
0.0017
Total
61
60
60
59
56
56
37
16
14
13
9
7
4
2
2
1
457
61
60
60
61
61
61
41
39
14
61
9
60
4
61
2
1
656
100.00
100.00
100.00
96.72
91.80
91.80
90.24
41.03
100.00
21.31
100.00
11.67
100.00
3.28
100.00
100.00
69.66
13.35
13.13
13.13
12.91
12.25
12.25
8.10
3.50
3.06
2.84
1.97
1.53
0.88
0.44
0.44
0.22
13.35
26.48
39.61
52.52
64.77
77.02
85.12
88.62
91.68
94.53
96.50
98.03
98.91
99.34
99.78
100.00
Observations from Table 19-4 include the following:
Twenty pollutants failed at least one screen for TOOK; 19 pollutants failed screens
for TMOK; 15 pollutants failed screens for PROK; 17 pollutants failed screens for
MWOK; and 16 pollutants failed screens for OCOK.
The risk-based screening process identified 11 pollutants of interest for TOOK, of
which eight are NATTS MQO Core Analytes. Cadmium and lead were added to the
pollutants of interest for TOOK because they are NATTS MQO Core Analytes, even
though they did not contribute to 95 percent of the total failed screens. Five additional
pollutants (beryllium, chloroform, tetrachloroethylene, trichloroethylene, and vinyl
chloride) were added to the pollutants of interest for TOOK because they are NATTS
MQO Core Analytes, even though they did not fail any screens. These five pollutants
do not appear in Table 19-4 but are shown in subsequent tables in the sections that
follow.
The risk-based screening process identified 12 pollutants of interest for TMOK, of
which eight are NATTS MQO Core Analytes. Cadmium and lead were added to the
pollutants of interest for TMOK because they are NATTS MQO Core Analytes, even
though they did not contribute to 95 percent of the total failed screens. Five additional
pollutants (beryllium, chloroform, tetrachloroethylene, trichloroethylene, and vinyl
19-33
-------
chloride) were added to the pollutants of interest for TMOK because they are NATTS
MQO Core Analytes, even though they did not fail any screens. These five pollutants
do not appear in Table 19-4 but are shown in subsequent tables in the sections that
follow.
The risk-based screening process identified nine pollutants of interest for PROK, of
which seven are NATTS MQO Core Analytes. An additional eight pollutants
(beryllium, cadmium, chloroform, lead, nickel, tetrachloroethylene, trichloroethylene,
and vinyl chloride) were added to the pollutants of interest for PROK because they
are NATTS MQO Core Analytes, even though they did not fail any screens. These six
pollutants do not appear in Table 19-4 but are shown in subsequent tables in the
sections that follow.
The risk-based screening process identified 11 pollutants of interest for MWOK, of
which seven are NATTS MQO Core Analytes. Nickel was added to the pollutants of
interest for MWOK because it is a NATTS MQO Core Analyte, even though it did
not contribute to 95 percent of the total failed screens. An additional seven pollutants
(beryllium, cadmium, chloroform, lead, tetrachloroethylene, trichloroethylene, and
vinyl chloride) were added to the pollutants of interest for MWOK because they are
NATTS MQO Core Analytes, even though they did not fail any screens. These seven
pollutants do not appear in Table 19-4 but are shown in subsequent tables in the
sections that follow.
The risk-based screening process identified 11 pollutants of interest for OCOK, of
which seven are NATTS MQO Core Analytes. Cadmium was added to the pollutants
of interest for OCOK because it is a NATTS MQO Core Analyte, even though it did
not contribute to 95 percent of the total failed screens. Seven additional pollutants
(beryllium, chloroform, lead, nickel, tetrachloroethylene, trichloroethylene, and vinyl
chloride) were added to the pollutants of interest for OCOK because they are NATTS
MQO Core Analytes, even though they did not fail any screens. These pollutants do
not appear in Table 19-4 but are shown in subsequent tables in the sections that
follow.
Acetaldehyde, benzene, and formaldehyde each failed 100 percent of screens for each
site.
TOOK and TMOK failed the fourth and fifth highest number of screens among all
NMP sites, although the other Oklahoma sites ranked 10th (OCOK), 11th (PROK), and
12th (MWOK), as shown in Table 4-8.
19-34
-------
19.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Oklahoma monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Oklahoma monitoring sites, where the data meet the
applicable criteria. Concentration averages for select pollutants are also presented graphically for
the sites to illustrate how the sites' concentrations compare to the program-level averages, as
presented in Section 4.1. In addition, concentration averages for select pollutants are presented
from previous years of sampling in order to characterize concentration trends at the sites.
Additional site-specific statistical summaries for each of the Oklahoma sites are provided in
Appendices J, L, and N.
19.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Oklahoma site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Oklahoma
monitoring sites are presented in Table 19-5, where applicable. Note that concentrations of the
TSP metals are presented in ng/m3 for ease of viewing. Also note that if a pollutant was not
detected in a given calendar quarter, the quarterly average simply reflects "0" because only zeros
substituted for non-detects were factored into the quarterly average concentration.
19-35
-------
Table 19-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Oklahoma Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Tulsa, Oklahoma - TOOK
Acetaldehyde
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
Ethylbenzene
Formaldehyde
Propionaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (TSP)a
Bery Ilium (TSP)a
Cadmium (TSP) a
Lead (TSP) a
Manganese (TSP) a
Nickel (TSP) a
56/56
57/57
52/57
57/57
17/57
51/57
57/57
56/56
56/56
47/57
8/57
3/57
56/56
56/56
56/56
56/56
56/56
56/56
NA
4.03
ฑ2.22
0.11
ฑ0.04
0.47
ฑ0.06
0.03
ฑ0.03
0.11
ฑ0.02
0.52
ฑ0.16
NA
NA
0.12
ฑ0.05
0.01
ฑ0.01
0
0.77
ฑ0.15
0.02
ฑ0.01
0.34
ฑ0.16
5.91
ฑ1.94
21.84
ฑ5.42
1.49
ฑ0.31
2.27
ฑ0.46
4.39
ฑ3.01
0.05
ฑ0.02
0.68
ฑ0.15
0.04
ฑ0.05
0.06
ฑ0.03
0.42
ฑ0.08
4.22
ฑ1.16
0.49
ฑ0.12
0.13
ฑ0.09
0.01
ฑ0.01
O.01
ฑO.01
0.70
ฑ0.14
0.03
ฑ0.01
0.39
ฑ0.21
6.41
ฑ2.21
29.22
ฑ7.69
1.69
ฑ0.41
4.49
ฑ0.95
3.81
ฑ1.53
0.09
ฑ0.02
0.64
ฑ0.03
0.04
ฑ0.04
0.29
ฑ0.06
0.69
ฑ0.24
5.61
ฑ1.21
0.77
ฑ0.18
0.14
ฑ0.09
0.01
ฑ0.01
O.01
ฑO.01
0.77
ฑ0.10
0.03
ฑ0.01
0.18
ฑ0.04
5.43
ฑ1.20
37.56
ฑ8.63
2.06
ฑ0.32
2.11
ฑ0.49
2.33
ฑ0.80
0.12
ฑ0.05
0.68
ฑ0.06
0.06
ฑ0.04
0.16
ฑ0.02
1.03
ฑ0.37
2.16
ฑ0.40
0.37
ฑ0.08
0.11
ฑ0.04
0.02
ฑ0.02
0
0.82
ฑ0.25
0.02
ฑ0.01
0.35
ฑ0.22
5.75
ฑ1.98
29.53
ฑ 13.51
1.70
ฑ0.52
2.75
ฑ0.41
3.59
ฑ0.98
0.09
ฑ0.02
0.63
ฑ0.05
0.04
ฑ0.02
0.15
ฑ0.03
0.68
ฑ0.13
3.74
ฑ0.57
0.51
ฑ0.07
0.12
ฑ0.03
0.01
ฑ0.01
O.01
ฑO.01
0.76
ฑ0.08
0.03
ฑ0.01
0.31
ฑ0.08
5.87
ฑ0.87
30.09
ฑ4.58
1.75
ฑ0.19
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for
ease of viewing.
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
19-36
-------
Table 19-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Oklahoma Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Tulsa, Oklahoma - TMOK
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (TSP)a
Bery Ilium (TSP)a
Cadmium (TSP) a
Lead (TSP) a
Manganese (TSP) a
Nickel (TSP) a
61/61
10/60
60/60
51/60
60/60
28/60
47/60
10/60
60/60
61/61
40/60
10/60
1/60
58/58
58/58
58/58
58/58
58/58
58/58
1.51
ฑ0.27
0.01
ฑ0.02
1.34
ฑ0.31
0.10
ฑ0.03
0.50
ฑ0.07
0.04
ฑ0.02
0.08
ฑ0.03
0
0.48
ฑ0.14
2.15
ฑ0.38
0.08
ฑ0.03
0.02
ฑ0.02
0
0.61
ฑ0.16
0.01
ฑ<0.01
0.27
ฑ0.05
5.08
ฑ1.16
14.93
ฑ5.09
1.21
ฑ0.30
2.00
ฑ0.43
0.16
ฑ0.18
1.14
ฑ0.30
0.04
ฑ0.03
0.61
ฑ0.06
0.05
ฑ0.03
0.05
ฑ0.04
0.03
ฑ0.02
0.40
ฑ0.11
4.44
ฑ1.35
0.04
ฑ0.03
0.02
ฑ0.02
0.01
ฑ0.01
0.59
ฑ0.12
0.02
ฑ0.01
0.20
ฑ0.03
4.76
ฑ1.12
24.93
ฑ6.60
1.58
ฑ0.38
4.05
ฑ0.67
0.02
ฑ0.03
1.54
ฑ0.37
0.13
ฑ0.04
0.65
ฑ0.04
0.15
ฑ0.11
0.11
ฑ0.03
0.01
ฑ0.02
0.63
ฑ0.13
6.04
ฑ1.31
0.07
ฑ0.03
0.01
ฑ0.02
0
0.58
ฑ0.12
0.02
ฑO.01
0.17
ฑ0.04
4.72
ฑ0.89
23.30
ฑ5.19
1.56
ฑ0.33
1.89
ฑ0.45
0.11
ฑ0.22
1.41
ฑ0.48
0.14
ฑ0.07
0.64
ฑ0.06
0.06
ฑ0.04
0.10
ฑ0.03
0.04
ฑ0.03
0.68
ฑ0.26
2.81
ฑ0.58
0.09
ฑ0.03
0.01
ฑ0.02
0
0.75
ฑ0.24
0.01
ฑO.01
0.24
ฑ0.08
5.13
ฑ2.00
18.29
ฑ7.30
1.33
ฑ0.52
2.40
ฑ0.34
0.08
ฑ0.07
1.35
ฑ0.18
0.10
ฑ0.02
0.60
ฑ0.03
0.07
ฑ0.03
0.08
ฑ0.02
0.02
ฑ0.01
0.55
ฑ0.09
3.93
ฑ0.62
0.07
ฑ0.02
0.01
ฑ0.01
0.01
ฑ0.01
0.63
ฑ0.08
0.02
ฑO.01
0.22
ฑ0.03
4.91
ฑ0.64
20.52
ฑ3.06
1.42
ฑ0.19
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for
ease of viewing.
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
19-37
-------
Table 19-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Oklahoma Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Pryor Creek, Oklahoma - PROK
Acetaldehyde
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (TSP)a
Bery Ilium (TSP)a
Cadmium (TSP) a
Lead (TSP) a
Manganese (TSP) a
Nickel (TSP) a
58/58
56/56
33/56
56/56
15/56
47/56
17/56
58/58
28/56
2/56
3/56
56/56
56/56
56/56
56/56
56/56
56/56
1.35
ฑ0.21
0.75
ฑ0.10
0.04
ฑ0.03
0.55
ฑ0.05
0.01
ฑ0.02
0.07
ฑ0.03
0.01
ฑ0.02
2.38
ฑ0.35
0.06
ฑ0.02
0
0
0.57
ฑ0.14
0.02
ฑ0.01
0.23
ฑ0.07
3.16
ฑ0.72
8.28
ฑ2.76
0.75
ฑ0.17
1.52
ฑ0.32
0.60
ฑ0.11
0.01
ฑ0.01
0.63
ฑ0.06
0.06
ฑ0.06
0.07
ฑ0.05
0.02
ฑ0.03
4.52
ฑ1.65
0.02
ฑ0.02
0
0.01
ฑ0.01
0.45
ฑ0.10
0.04
ฑ0.02
0.13
ฑ0.04
2.46
ฑ0.60
11.95
ฑ3.87
0.89
ฑ0.24
2.43
ฑ0.38
0.70
ฑ0.27
0.03
ฑ0.02
0.66
ฑ0.05
0.01
ฑ0.02
0.54
ฑ0.21
0.01
ฑ0.02
5.96
ฑ1.43
0.01
ฑ0.01
0.01
ฑ0.02
0.01
ฑ0.01
0.53
ฑ0.16
0.03
ฑ0.01
0.13
ฑ0.03
2.57
ฑ0.62
15.28
ฑ5.10
0.88
ฑ0.14
1.38
ฑ0.26
0.67
ฑ0.14
0.05
ฑ0.03
0.65
ฑ0.06
0.05
ฑ0.03
0.17
ฑ0.02
0.06
ฑ0.02
2.43
ฑ0.73
0.05
ฑ0.02
O.01
ฑ0.01
0.01
ฑ0.01
0.59
ฑ0.14
0.02
ฑ0.01
0.14
ฑ0.03
2.58
ฑ0.52
9.41
ฑ2.23
0.64
ฑ0.14
1.68
ฑ0.18
0.68
ฑ0.08
0.04
ฑ0.01
0.62
ฑ0.03
0.03
ฑ0.02
0.20
ฑ0.07
0.03
ฑ0.01
3.84
ฑ0.67
0.03
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
0.54
ฑ0.07
0.03
ฑ0.01
0.16
ฑ0.02
2.69
ฑ0.30
11.31
ฑ1.88
0.79
ฑ0.09
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for
ease of viewing.
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
19-38
-------
Table 19-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Oklahoma Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Midwest City, Oklahoma - MWOK
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (TSP)a
Bery Ilium (TSP)a
Cadmium (TSP) a
Lead (TSP) a
Manganese (TSP) a
Nickel (TSP) a
56/56
5/56
56/56
40/56
56/56
23/56
50/56
9/56
56/56
56/56
40/56
1/56
1/56
56/56
56/56
56/56
56/56
56/56
56/56
1.52
ฑ0.44
0.01
ฑ0.02
0.84
ฑ0.16
0.09
ฑ0.05
0.49
ฑ0.07
0.04
ฑ0.02
0.09
ฑ0.02
0
0.23
ฑ0.09
2.61
ฑ0.47
0.25
ฑ0.19
0.01
ฑ0.02
0
0.39
ฑ0.08
0.01
ฑ0.01
0.11
ฑ0.02
2.33
ฑ0.34
9.17
ฑ2.63
0.93
ฑ0.24
1.66
ฑ0.27
0.02
ฑ0.02
0.64
ฑ0.09
0.04
ฑ0.02
0.62
ฑ0.06
0.05
ฑ0.03
0.09
ฑ0.03
0.03
ฑ0.02
0.18
ฑ0.03
3.85
ฑ0.96
0.13
ฑ0.08
0
0
0.42
ฑ0.06
0.02
ฑ0.01
0.18
ฑ0.06
2.79
ฑ0.50
15.24
ฑ3.98
1.54
ฑ0.63
2.98
ฑ0.39
0
0.69
ฑ0.11
0.04
ฑ0.02
0.66
ฑ0.06
0.01
ฑ0.02
0.10
ฑ0.03
0
0.25
ฑ0.04
5.99
ฑ0.97
0.08
ฑ0.09
0
0.01
ฑ0.01
0.32
ฑ0.06
0.03
ฑ0.01
0.08
ฑ0.02
2.35
ฑ0.50
16.17
ฑ4.43
1.26
ฑ0.30
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2.03
ฑ0.24
0.01
ฑ0.01
0.73
ฑ0.07
0.06
ฑ0.02
0.60
ฑ0.03
0.04
ฑ0.01
0.09
ฑ0.01
0.01
ฑ0.01
0.25
ฑ0.04
4.05
ฑ0.53
0.15
ฑ0.06
O.01
ฑO.01
0.01
ฑ0.01
0.40
ฑ0.04
0.02
ฑO.01
0.12
ฑ0.02
2.48
ฑ0.22
13.26
ฑ1.94
1.20
ฑ0.21
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for
ease of viewing.
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
19-39
-------
Table 19-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Oklahoma Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Oklahoma City, Oklahoma - OCOK
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (TSP)a
Bery Ilium (TSP)a
Cadmium (TSP) a
Lead (TSP) a
Manganese (TSP) a
Nickel (TSP) a
60/60
9/61
61/61
41/61
61/61
13/61
39/61
14/61
61/61
60/60
40/61
1/61
3/61
61/61
61/61
61/61
61/61
61/61
61/61
1.44
ฑ0.27
0.02
ฑ0.04
0.75
ฑ0.11
0.04
ฑ0.03
0.46
ฑ0.11
0.03
ฑ0.02
0.04
ฑ0.02
0
0.23
ฑ0.05
2.01
ฑ0.36
0.11
ฑ0.06
0
0
0.47
ฑ0.10
0.02
ฑ0.01
0.15
ฑ0.07
2.87
ฑ0.54
12.42
ฑ3.49
0.85
ฑ0.15
2.50
ฑ0.79
0.23
ฑ0.20
0.70
ฑ0.15
0.01
ฑ0.01
0.61
ฑ0.08
0.02
ฑ0.02
0.01
ฑ0.02
0.03
ฑ0.03
0.25
ฑ0.07
5.70
ฑ2.56
0.04
ฑ0.03
0
0
0.48
ฑ0.11
0.02
ฑ0.01
0.15
ฑ0.09
2.78
ฑ0.48
16.94
ฑ4.71
1.03
ฑ0.20
3.69
ฑ0.50
0.01
ฑ0.02
1.12
ฑ0.79
0.64
ฑ1.21
0.65
ฑ0.05
0.01
ฑ0.01
0.10
ฑ0.03
0.01
ฑ0.01
0.38
ฑ0.06
5.82
ฑ0.91
0.05
ฑ0.03
0
0.01
ฑ0.01
0.36
ฑ0.07
0.02
ฑO.01
0.08
ฑ0.05
2.15
ฑ0.34
16.28
ฑ4.79
0.79
ฑ0.12
1.86
ฑ0.37
0.02
ฑ0.04
0.93
ฑ0.21
0.08
ฑ0.04
0.61
ฑ0.06
0.02
ฑ0.02
0.07
ฑ0.02
0.09
ฑ0.09
0.38
ฑ0.11
2.46
ฑ0.61
0.13
ฑ0.05
0.01
ฑ0.01
0.01
ฑ0.01
0.57
ฑ0.22
0.01
ฑO.01
0.12
ฑ0.03
2.68
ฑ0.73
10.35
ฑ2.51
0.70
ฑ0.10
2.41
ฑ0.33
0.07
ฑ0.05
0.88
ฑ0.21
0.20
ฑ0.31
0.58
ฑ0.04
0.02
ฑ0.01
0.06
ฑ0.01
0.03
ฑ0.02
0.31
ฑ0.04
4.06
ฑ0.80
0.08
ฑ0.02
O.01
ฑO.01
0.01
ฑ0.01
0.47
ฑ0.07
0.02
ฑO.01
0.13
ฑ0.03
2.61
ฑ0.26
14.04
ฑ2.01
0.84
ฑ0.08
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for
ease of viewing.
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
19-40
-------
Observations for all five Oklahoma sites from Table 19-5 include the following:
Formaldehyde has the highest annual average concentration by mass for each site,
followed by acetaldehyde and benzene, with one exception. The annual average
concentration of benzene is greater than the annual average concentration of
acetaldehyde for TOOK.
The annual average concentrations of formaldehyde range from 3.74 ฑ 0.57 |ig/m3 for
TOOK to 4.06 ฑ 0.80 |ig/m3 for OCOK, although the annual averages for MWOK
and OCOK are nearly identical. The annual average concentration of acetaldehyde
ranged from 1.68 ฑ 0.18 |ig/m3 for PROK to 2.75 ฑ 0.41 |ig/m3 for TOOK.
Concentrations of the carbonyl compounds, formaldehyde in particular, tended to be
highest in the summer months and lowest in the winter months. However, the
relatively large confidence intervals associated with these averages indicate that, in
most cases, the differences are not statistically significant.
The annual average concentration of benzene is highest for TOOK and TMOK. These
are the only two Oklahoma sites for which the annual average is greater than 1 |ig/m3.
However, the annual average for TOOK (3.59 ฑ 0.98 |ig/m3) is nearly three times the
annual average for TMOK (1.35 ฑ 0.18 Hg/m3).
The annual average concentration of manganese is the highest of the TSP metals for
each site, followed by lead and nickel. The annual average manganese concentrations
range from 11.31 ฑ 1.88 |ig/m3 for PROK to 30.09 ฑ 4.58 |ig/m3 for TOOK.
Concentrations of the TSP metals tended to be higher at TOOK and TMOK than
PROK, OCOK, and MWOK.
Observations for TOOK from Table 19-5 include the following:
The first, second, and third quarter average concentrations of benzene for TOOK have
relatively large confidence intervals associated with them, particularly the second
quarter. The maximum benzene concentration was measured on April 3, 2011
(23.8 |ig/m3) and is nearly twice the next highest concentration of benzene
(12.6 |ig/m3), measured on January 15, 2011. The April 3rd measurement is also the
maximum concentration of benzene measured across the program. Of the four
concentrations of benzene greater than 10 |ig/m3 measured at TOOK, two were
measured in the first quarter and one each in the second and third quarters. Of the
27 concentrations of benzene greater than 4 |ig/m3 measured across the program, 19
were measured at TOOK. No other NMP site had more than two benzene
measurements greater than 4 |ig/m3 (OCOK had one). Similar observations for the
benzene measurements collected at TOOK were made in the 2010 NMP report.
19-41
-------
Concentrations ofp-dichlorobenzene were highest in the third quarter of 2011 at
TOOK. A review of the data shows that the four highest concentrations of this
pollutant were measured in July 2011 and of the 15 concentrations greater than
0.2 |ig/m3, 12 were measured between July and September.
The fourth quarter average concentration of ethylbenzene is higher than the other
quarterly averages. A review of the data shows that six of the seven highest
concentrations measured at TOOK were measured during the fourth quarter of 2011,
including the only two concentrations greater than 2 |ig/m3.
Although the third quarter average concentration of manganese is greater than the
fourth quarter average, the fourth quarter has a larger confidence interval associated
with it. A review of the data shows that the maximum concentration of manganese
was measured at TOOK on October 6, 2011 (104 ng/m3). The second highest
concentration was measured on the previous sample day, September 30, 2011
(64.5 ng/m3). Of the 14 manganese concentrations greater than 40 ng/m3, nine were
measured during the third quarter of 2011, while only one was measured during the
fourth quarter. Thus, manganese concentrations were generally higher during the third
quarter, while a single outlier is driving the fourth quarter average concentration.
TOOK does not have first quarter averages for the carbonyl compounds due to
complications at the site during this time frame.
Observations for TMOK from Table 19-5 include the following:
Each of the quarterly average concentrations of acrylonitrile has a confidence interval
greater than the average itself, particularly the second and fourth quarters. A review
of the data shows that concentrations of acrylonitrile spanned an order of magnitude,
ranging from 0.109 |ig/m3 to 1.69 |ig/m3. Two concentrations greater than 1 |ig/m3
were measured at TMOK, one in June and one in December. The December 29, 2011
measurement (1.69 |ig/m3) is the maximum acrylonitrile concentration measured
among all NMP sites sampling VOCs (while the June 14, 2011 measurement ranked
seventh across the program). However, acrylonitrile was detected only 10 times at
TMOK, leading to the substitution of many zeros for non-detects in the calculations.
The third quarter average chloroform concentration is two to three times higher than
the other quarterly average concentrations. A review of the data shows that five of the
six concentrations greater than 2 |ig/m3 were measured during the third quarter of
2011. In addition, the third quarter has the fewest non-detects of chloroform (6),
while the number of non-detects in the other quarters range from seven (first quarter)
to 10 (fourth quarter).
Each of the quarterly average concentrations of manganese has a relatively large
confidence interval associated with it, particularly the fourth quarter average. A
review of the data shows that the maximum concentration of manganese was
measured at TMOK on October 6, 2011 (65.6 ng/m3), which is the same day the
maximum manganese concentration was measured at TOOK. The next highest
concentration measured during the fourth quarter was considerably less (25.1 ng/m3).
19-42
-------
A manganese measurement greater than 40 ng/m3 was measured in three of the four
calendar quarters. The second quarter of 2011 has the greatest number of
concentrations greater than 30 ng/m3 (5), followed by four in the third quarter and one
each in the first and fourth quarters. This explains the relatively high-level of
variability shown in the quarterly averages.
Observations for PROK from Table 19-5 include the following:
The third quarter average concentration ofp-dichlorobenzene is more than seven
times higher than the other quarterly averages. A review of the data shows that the
only two measurements greater than 1 |ig/m3 were both measured in July. These two
measurements account for half of the/>-dichlorobenzene concentrations greater than
1 |ig/m3 measured across all NMP sites sampling VOCs. The eight highest
concentrations ofp-dichlorobenzene measured at PROK (those greater than
0.35 |ig/m3) were measured during the third quarter.
The third quarter average manganese concentration is greater than the other quarterly
averages and has a relatively large confidence interval associated with it. The
maximum manganese concentration (43.8 ng/m3) was measured on
September 30, 2011, which is the day the second and third highest manganese
concentrations were measured at TOOK and TMOK, respectively. The second
highest manganese concentration measured at PROK was half as high (23.0 ng/m3),
but also measured during the third quarter.
Observations for MWOK from Table 19-5 include the following:
The annual average concentration of formaldehyde for MWOK is nearly identical to
the annual average concentration for OCOK, which has the highest annual average
concentration of formaldehyde among the Oklahoma monitoring sites. The maximum
concentration of formaldehyde was measured at MWOK on August 25, 2011
(7.10 |ig/m3), although the five highest concentrations were all measured in July or
August. Twelve of the 17 concentrations greater than 5 |ig/m3 were measured during
the third quarter, with four in the second quarter and one in the fourth quarter.
The first quarter average concentration of tetrachloroethylene is two and three times
greater than the second and third quarter averages, respectively, and has a relatively
large confidence interval associated with it. A review of the data shows that the
maximum concentration of this pollutant was measured on March 4, 2011
(1.45 |ig/m3). This concentration is the only measurement greater than 1 |ig/m3
measured at MWOK and is nearly three times higher than the next highest
tetrachloroethylene concentration (0.571 |ig/m3). This measurement is also the ninth
highest tetrachloroethylene concentration measured across all NMP sites sampling
VOCs.
There are no fourth quarter average concentrations in Table 19-5 for MWOK because
sampling was discontinued at this site at the end of November.
19-43
-------
Observations for OCOK from Table 19-5 include the following:
The second quarter acrylonitrile average for OCOK is higher than the other quarterly
averages and has a relatively large confidence interval associated with it. The
maximum concentration of acrylonitrile was measured on May 9, 2011 (1.27 |ig/m3)
and is nearly twice the next highest concentration (0.644 |ig/m3) measured on
June 20, 2011. The May 9th measurement is the ninth highest concentration measured
among sites sampling VOCs and OCOK is one of only five sites to measure an
acrylonitrile concentration greater than 1 |ig/m3 (TMOK is one of the other four).
However, acrylonitrile was detected only nine times at OCOK, leading to the
substitution of many zeros for non-detects in the calculations, which explains the
relatively large confidence intervals for each quarterly average.
The third quarter average concentrations of benzene and 1,3-butadiene are higher than
the other quarterly averages and have relatively large confidence intervals,
particularly for 1,3-butadiene. The maximum concentration of each pollutant was
measured on September 18, 2011. The benzene concentration for this date
(6.81 |ig/m3) is nearly four times higher than the next highest concentration measured
at OCOK and the eighth highest benzene concentration measured across the program.
The 1,3-butadiene concentration for this date (9.51 |ig/m3) is nearly forty times
higher than the next highest concentration measured at OCOK. This 1,3-butadiene
concentration is not only the maximum concentration measured across the program,
but is more than three times higher than the next highest concentration measured
across the program (2.68 |ig/m3, measured at NBIL).
OCOK has the highest annual average concentration of formaldehyde among the
Oklahoma sites. The maximum formaldehyde concentration measured at OCOK was
measured on May 9, 2011 (19.6 |ig/m3) and is the third highest concentration of
formaldehyde measured among NMP sites sampling carbonyl compounds. The
second and third quarter average concentrations are significantly greater than the
other quarterly averages. Although the second and third quarter averages are similar
to each other, the second quarter average has a relatively large confidence interval
associated with it, indicating that outlier(s) may be affecting the average
concentration. The three highest formaldehyde concentrations measured at OCOK
were measured between April 27, 2011 and May 9, 2011 and range from 9.10 |ig/m3
to 19.6 |ig/m3. Of the 20 formaldehyde concentrations greater than 5 |ig/m3, only one
was measured outside of the second or third quarter. The range of formaldehyde
concentrations for the second quarter is 1.06 |ig/m3 to 19.6 |ig/m3 with a median
concentration of 4.55 |ig/m3. The range of formaldehyde concentrations for the third
quarter is 2.90 |ig/m3 to 8.59 |ig/m3 with a median concentration of 6.07 |ig/m3.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the
Oklahoma sites include the following:
The Oklahoma sites appear in Tables 4-9 through 4-12 a total of 57 times. However,
because they are the only sites sampling TSP metals, all five sites appear for each
metal, accounting for 30 of the appearances.
19-44
-------
TOOK has the highest annual average of concentration of benzene among all NMP
sites sampling this pollutant. Similar findings were observed in the 2010 NMP report.
The annual average for TMOK ranks fourth.
The annual average concentrations for four of the five Oklahoma sites ranked among
the highest annual average concentrations ofp-dichlorobenzene, with PROK ranking
the highest at third. OCOK, the only site that does not appear in Table 4-9 for
/>-dichlorobenzene, ranks 12th.
OCOK ranks third highest for 1,2-dichloroethane and 1,3-butadiene. TOOK ranks
third highest for ethylbenzene and MWOK ranks third highest for
hexachl oro-1,3 -butadi ene.
All five Oklahoma sites appear in Table 4-10 for their annual average concentrations
of formaldehyde, ranking third through seventh among sites sampling carbonyl
compounds. TOOK ranks fourth for acetaldehyde while OCOK and TMOK rank
seventh and eighth, respectively.
Of the six TSP metals shown in Table 4-12, TOOK has the highest annual average
concentration of five of them among the Oklahoma sites. The only exception is for
beryllium, where PROK ranks highest and TOOK ranks second.
19.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde, arsenic,
benzene, 1,3-butadiene, formaldehyde, lead, and manganese were created for the Oklahoma
sites. Figures 19-24 through 19-30 overlay the sites' minimum, annual average, and maximum
concentrations onto the program-level minimum, first quartile, median, average, third quartile,
and maximum concentrations, as described in Section 3.5.3.
19-45
-------
Figure 19-24. Program vs. Site-Specific Average Acetaldehyde Concentrations
FF.CK
[,",'; CK
OCOK
6 B
Concentration (|
10
16
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
19-46
-------
Figure 19-25. Program vs. Site-Specific Average Arsenic (TSP) Concentrations
FF.CK
[,",'; CK
OCOK
j.25
3.5
0.75 1 1.25
Concentration (ng/m3)
1.5
1.75
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
19-47
-------
Figure 19-26. Program vs. Site-Specific Average Benzene Concentrations
TOOK
TMOK
PROK
MWOK
OCOK
;
1
i Program Max Concentration = 23. 8 ng/m3 ]
Program Max Concentration = 23. 8 |ag/nna
1 1
~! ! Program Max Concentration = 23. 8 uE/m3
L i Program Max Concentration = 23. 8 ng/m3
i
J _,
\ Program Max Concentration = 23. 8 ng/m3 j
12345 S7B91
Concentration (^g/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
D D
Site: Site Average Site Minimum/Maximum
o
19-48
-------
Figure 19-27. Program vs. Site-Specific Average 1,3-Butadiene Concentrations
-rrk UA
r
i
TMOK B-O
PRCK H I
r
i
MWOK ปJ-
.
"r"K H-
D
Program Max Concentration 9.51 ng/ms
Program Max Concentratfon = 9.51 ng/ms
i Program Max Concentration = 9.51 (Jg/m3
i Program Max Concentration = 9.51 (Jg/m-
i Program Max Concentratin = 9.51 ng/m3
0.5 1 1.5 2 2.5 :
Concentration (^g/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
D D
Site: Site Average Site Minimum/Maximum
o
19-49
-------
Figure 19-28. Program vs. Site-Specific Average Formaldehyde Concentrations
mฑ
FF.CK
[,",'; CK
OCOK
10
15
Concentration (|
20
25
50
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
o
19-50
-------
Figure 19-29. Program vs. Site-Specific Average Lead (TSP) Concentrations
FF.CK
[,",'; CK
OCOK
10 12
Concentration (ng/m3)
16
IE
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
19-51
-------
Figure 19-30. Program vs. Site-Specific Average Manganese (TSP) Concentrations
FRCK
[,",'; CK
OCOK
40
ฃ3
Concentration (ng/m3)
153
123
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 19-24 through 19-30 include the following:
Figure 19-24 shows that the annual average acetaldehyde concentrations for
TOOK, TMOK, and OCOK are greater than the program-level average for
acetaldehyde. The annual average for TOOK is also greater than the program-
level third quartile. The annual average acetaldehyde concentration for MWOK is
similar to the program-level average while the annual average for PROK is less
than the program-level average and equivalent to the program-level median
concentration. The range of acetaldehyde concentrations is largest for TOOK and
smallest for PROK. There were no non-detects of acetaldehyde reported for the
Oklahoma sites or across the program.
Because the Oklahoma sites are the only sites sampling TSP metals, Figure 19-25
compares the individual Oklahoma site data against the combined Oklahoma data.
Figure 19-25 shows that the annual average arsenic (TSP) concentration is
greatest for TOOK and least for MWOK. This figure also shows that the range of
measurements of arsenic is largest for OCOK, where the maximum arsenic (TSP)
concentration was measured, although similar concentrations were also measured
19-52
-------
at TOOK and TMOK. The minimum arsenic concentration measured among the
five sites sampling TSP metals was measured at PROK.
Figure 19-26 presents the box plots for benzene. Note that the program-level
maximum concentration (23.8 |ig/m3) is not shown directly on each box plot
because the scale of the box plot would be too large to readily observe data points
at the lower end of the concentration range. Thus, the scale has been reduced to
10 |ig/m3. Figure 19-26 shows that the annual average concentration of benzene
for TOOK and TMOK are greater than the program-level average while the
annual average concentration of benzene for PROK, MWOK, and OCOK are less
than the program-level average. The annual average benzene concentration for
TOOK is at least twice the other sites' annual averages. The maximum benzene
concentration measured at TOOK is the maximum benzene concentration
measured across the program. There were no non-detects of benzene measured at
the Oklahoma sites.
Figure 19-27 presents the box plots for 1,3-butadiene. Similar to the box plots for
benzene, the program-level maximum concentration (9.51 |ig/m3) is not shown
directly on the box plots as the scale has been reduced to 3 |ig/m3 to allow for the
observation of data points at the lower end of the concentration range. The
maximum concentration of 1,3-buadiene measured across the program was
measured at OCOK. The annual average 1,3-butadiene concentration for OCOK
is twice the program-level average concentration, while the annual averages for
TOOK and TMOK are similar to the program-level average and the annual
averages for PROK and MWOK are less than the program-level average. Several
non-detects of 1,3-butadiene were measured at the Oklahoma sites, as indicated
by the minimum concentration for each site.
Figure 19-28 shows that the annual average formaldehyde concentration for each
Oklahoma site is greater than the program-level average concentration and third
quartile. Although the annual average concentrations of formaldehyde did not
vary significantly among the Oklahoma sites, the maximum concentration
measured at OCOK is roughly twice the maximum concentration measured at the
other four sites, although all are less than the maximum concentration measured
across the program. There were no non-detects of formaldehyde measured at the
Oklahoma sites or across the program.
Because the Oklahoma sites are the only monitoring sites sampling TSP metals,
Figure 19-29 compares the individual Oklahoma site lead data against the
combined Oklahoma data. Figure 19-29 shows that the annual average lead (TSP)
concentration is greatest for TOOK and TMOK and lowest for PROK, MWOK,
and OCOK (note that the annual averages for these three sites are not that
different from each other). This figure also shows that the range of lead
measurements was greatest for TOOK and TMOK and smallest for MWOK. The
maximum manganese (TSP) concentration was measured at TOOK.
19-53
-------
Figure 19-30 compares the individual Oklahoma site manganese data against the
combined Oklahoma data. Figure 19-30 shows that the annual average manganese
(TSP) concentration is highest for TOOK and lowest for PROK. Figure 19-30
also shows that the range of manganese measurements was greatest for TOOK
and smallest for MWOK.
19.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. TOOK has sampled TSP metals, carbonyl compounds, and VOCs since 2006;
thus, Figures 19-31 through 19-37 present the annual statistical metrics for acetaldehyde, arsenic,
benzene, 1,3-butadiene, formaldehyde, lead, and manganese, respectively. The statistical metrics
presented for assessing trends include the substitution of zeros for non-detects.
Figure 19-31. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at TOOK
1 c
I 6
e
a
3
ft 4 _
E q
2 -
1 -
ฃ f
2007 2008
^
20O9
Year
# 5th Percentile Minimum Median
*
T
I 1
2010 2011
Maximum 95th Percentile .,+.. Average
19-54
-------
Figure 19-32. Annual Statistical Metrics for Arsenic (TSP) Concentrations
Measured at TOOK
2009
Year
5th Percentile Minimum Median Maximum * 95th Percentile +.^.* Average
Figure 19-33. Annual Statistical Metrics for Benzene Concentrations
Measured at TOOK
2009
Year
# 5th Percentile Minimum Median Maximum
95th Percentile ..^.. Average
19-55
-------
Figure 19-34. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at TOOK
.'
t rat ion (ME/I
e
rage ton con
5
<
0.05 -
"
*"*-
r
^7
'
.*
2007 2008 20O9 2010 2011
Year
5th Percentile Minimum Median
Maximum
95t
age
Figure 19-35. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at TOOK
B
a
i
3
1
<
^....
....^
.ป,
^
I
...*
!
2007 2008 2009 2010 2011
Year
# 5th Percentile Min mum Median
Maximum 4
95th Percentile *
Average
19-56
-------
Figure 19-36. Annual Statistical Metrics for Lead (TSP) Concentrations
Measured at TOOK
ralk.ii (ng/ni3)
', j
i
I
15 jn
d
b.
2007
I
I *
>.. 1 I
ft ป ' ' *
200B 20O9 2010 2011
Year
5th Percentile - Min
,. . , .
1
Figure 19-37. Annual Statistical Metrics for Manganese (TSP) Concentrations
Measured at TOOK
# 5th Percentile Minimum Median Maximum
95th Percentile ..^.. Average
19-57
-------
Observations from Figure 19-31 for acetaldehyde measurements at TOOK include the
following:
Although TOOK began sampling carbonyl compounds in January 2006, equipment
complications at the onset of sampling resulted in fewer than 85 percent valid
samples in 2006; thus, Figure 19-31 excludes data from 2006 per the criteria specified
in Section 3.5.4.
The maximum concentration of acetaldehyde was measured in 2011 (8.95 |ig/m3).
The five highest concentrations were all measured in 2011. Of the 16 acetaldehyde
concentrations greater than 4 |ig/m3 measured at TOOK, half were measured in 2011,
five were measured in 2010, and one was measured in each of the other years shown.
The average concentration exhibits an increasing trend since 2009. Nearly all of the
statistical metrics shown have been increasing since 2009.
The minimum concentration measured for each year shown is greater than zero,
indicating that there were no non-detects of acetaldehyde reported over the years at
TOOK.
Observations from Figure 19-32 for arsenic (TSP) measurements at TOOK include the
following:
Although TOOK began sampling TSP metals in 2006, sampling did not begin until
October, which does not yield enough samples for the statistical metrics to be
calculated; thus, Figure 19-32 excludes data from 2006 per the criteria specified in
Section 3.5.4.
The two highest concentrations of arsenic were measured at TOOK in September
2007. These are the only two concentrations greater than 4 ng/m3 measured at TOOK.
The average and median concentrations exhibit a decreasing trend from 2007 to 2009.
The average concentration of arsenic did not change significantly from 2009 to 2010
while the median decreased slightly. Although a slight increase in the average and
median concentrations is shown for 2011, the maximum and 95th percentiles actually
decreased and the median for 2011 is actually slightly greater than the average
concentration.
The minimum concentration measured for each year shown is greater than zero,
indicating that there were no non-detects of arsenic reported over the years at TOOK.
Observations from Figure 19-33 for benzene measurements at TOOK include the
following:
Although TOOK began sampling VOCs in January 2006, equipment complications at
the onset of sampling resulted in fewer than 85 percent valid samples in 2006; thus,
Figure 19-33 excludes data from 2006.
19-58
-------
The maximum concentration of benzene was measured in 2011 (23.8 |ig/m3). The
four highest concentrations were all measured in 2011 and are greater than 10 |ig/m3.
The 95th percentile for 2011 is greater than the maximum concentration for each of
the previous years.
The average benzene concentration has fluctuated over the years. After a substantial
decrease from 2008 to 2009, most of the statistical parameters increased for 2010, an
increase that continued into 2011.
The difference between the average and median concentrations nearly tripled from
2010 to 2011. This is a further indication of the increasing variability of the 2011
benzene measurements. The median represents the mid-point of the dataset, which
increased by more than 0.5 |ig/m3 from 2010 to 2011. The average, which is
influenced more by outliers, such as the maximum concentration measured in 2011,
increased by more than 1.25 |ig/m3 from 2010 to 2011.
The minimum concentration measured for each year shown is greater than zero,
indicating that there were no non-detects of benzene reported over the years at
TOOK.
Observations from Figure 19-34 for 1,3-butadiene measurements at TOOK include the
following:
Similar to other pollutants, the maximum concentration of 1,3-butadiene was
measured in 2011 (0.34 |ig/m3), although a similar concentration was also measured
in 2007 (0.33 |ig/m3).
After an initial decrease from 2007 to 2008 and little change in 2009, the average
concentration began to increase, with the greatest increase occurring from 2010 to
2011. With the exception of the minimum and 5th percentile, all of the statistical
metrics increased for 2011.
The minimum concentration for 2007 is greater than zero, indicating that non-detects
of 1,3-butadiene were not reported. For 2008 and 2009, the minimum concentration
shown is zero, indicating that at least one non-detect was measured during those
years. For 2010 and 2011, both the minimum concentration and 5th percentile are
zero, indicating that additional non-detects were reported. The percentage of non-
detects for 2010 and 2011 is less than nine percent.
Observations from Figure 19-35 for formaldehyde measurements at TOOK include the
following:
The maximum concentration of formaldehyde (10.1 |ig/m3) was measured at TOOK
on August 19, 2011, the same day the maximum acetaldehyde concentration was
measured.
19-59
-------
Similar to acetaldehyde, an increasing trend is shown for formaldehyde from 2009 to
2010 and 2011. However, due to the higher level of variability in the formaldehyde
measurements as a whole, the difference is not statistically significant.
The minimum concentration measured for each year shown is greater than zero,
indicating that there were no non-detects of formaldehyde reported over the years at
TOOK.
Observations from Figure 19-36 for lead (TSP) measurements at TOOK include the
following:
The maximum concentration of lead was measured in 2008 (50.5 ng/m3). Four of the
five highest concentrations of lead were measured in 2008.
Although most of the statistical parameters increased from 2007 to 2008, the median
concentration actually decreased. This indicates that the higher concentrations
measured in 2008 were likely driving the average concentration while a higher
percentage of measurements were actually lower than in 2007.
A significant decrease is shown for most of the statistical parameters from 2008 to
2009, with additional slight decreases for 2010.
Nearly all of the statistical parameters increased for 2011.
The minimum concentration measured for each year shown is greater than zero,
indicating that there were no non-detects of lead reported over the years at TOOK.
Observations from Figure 19-37 for manganese (TSP) measurements at TOOK include
the following:
The maximum concentration of manganese was measured in 2007 (131 ng/m3),
although another measurement greater than 100 ng/m3 was also measured in 2011
(104 ng/m3).
A steady decreasing trend in the average and median concentrations through 2009
was followed by an increasing trend for 2010 and 2011. The average concentration
for 2007 is similar to the average concentration for 2011.
The minimum concentration measured for each year shown is greater than zero,
indicating that there were no non-detects of manganese reported over the years at
TOOK.
19-60
-------
19.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at
each Oklahoma monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
19.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Oklahoma monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
19.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Oklahoma monitoring sites and where annual
average concentrations could be calculated, risk was examined by calculating cancer risk and
noncancer hazard approximations. These approximations can be used as risk estimates for cancer
and noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 19-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
19-61
-------
Table 19-6. Risk Approximations for the Oklahoma Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Tulsa, Oklahoma - TOOK
Acetaldehyde
Arsenic (TSP)a
Benzene
Beryllium (TSP)a
1,3 -Butadiene
Cadmium (TSP)a
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
Ethylbenzene
Formaldehyde
Lead (TSP)a
Manganese (TSP)a
Nickel (TSP)a
Propionaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.0043
0.0000078
0.0024
0.00003
0.0018
0.000006
0.000011
0.0000025
0.000013
0.00048
0.00000026
0.0000048
0.0000088
0.009
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
0.8
1
0.0098
0.00015
0.00005
0.00009
0.008
0.04
0.002
0.1
56/56
56/56
57/57
56/56
52/57
56/56
57/57
17/57
51/57
57/57
56/56
56/56
56/56
56/56
56/56
47/57
8/57
3/57
2.75
ฑ0.41
0.01
ฑ0.01
3.59
ฑ0.98
0.01
ฑO.01
0.09
ฑ0.02
O.01
ฑO.01
0.63
ฑ0.05
0.04
ฑ0.02
0.15
ฑ0.03
0.68
ฑ0.13
3.74
ฑ0.57
0.01
ฑO.01
0.03
ฑ0.01
O.01
ฑO.01
0.51
ฑ0.07
0.12
ฑ0.03
0.01
ฑ0.01
O.01
ฑO.01
6.04
3.27
28.02
0.06
2.70
0.55
3.76
1.70
1.70
48.62
0.84
0.03
0.05
0.01
0.31
0.05
0.12
O.01
0.05
0.03
0.01
O.01
0.01
O.01
0.38
0.04
0.60
0.02
0.06
O.01
0.01
O.01
- = a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 19-5.
19-62
-------
Table 19-6. Risk Approximations for the Oklahoma Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Tulsa, Oklahoma - TMOK
Acetaldehyde
Acrylonitrile
Arsenic (TSP)a
Benzene
Beryllium (TSP)a
1,3 -Butadiene
Cadmium (TSP) a
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Lead (TSP)a
Manganese (TSP)a
Nickel (TSP)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0043
0.0000078
0.0024
0.00003
0.0018
0.000006
0.000011
0.000026
0.0000025
0.000013
0.00048
0.00000026
0.0000048
0.0000088
0.009
0.002
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
0.8
2.4
1
0.0098
0.00015
0.00005
0.00009
0.04
0.002
0.1
61/61
10/60
58/58
60/60
58/58
51/60
58/58
60/60
28/60
47/60
10/60
60/60
61/61
58/58
58/58
58/58
40/60
10/60
1/60
2.40
ฑ0.34
0.08
ฑ0.07
<0.01
ฑ0.01
1.35
ฑ0.18
0.01
ฑ0.01
0.10
ฑ0.02
0.01
ฑ0.01
0.60
ฑ0.03
0.07
ฑ0.03
0.08
ฑ0.02
0.02
ฑ0.01
0.55
ฑ0.09
3.93
ฑ0.62
O.01
ฑO.01
0.02
ฑ0.01
O.01
ฑO.01
0.07
ฑ0.02
0.01
ฑ0.01
0.01
ฑ0.01
5.28
5.36
2.73
10.54
0.04
3.07
0.39
3.61
0.91
0.47
1.37
51.15
0.68
0.02
0.06
0.01
0.27
0.04
0.04
0.05
0.01
0.05
0.02
0.01
0.01
O.01
0.01
O.01
0.40
0.03
0.41
0.02
0.01
0.01
0.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 19-5.
19-63
-------
Table 19-6. Risk Approximations for the Oklahoma Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Pryor Creek, Oklahoma - PROK
Acetaldehyde
Arsenic (TSP) a
Benzene
Beryllium (TSP)a
1,3 -Butadiene
Cadmium (TSP)a
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Formaldehyde
Lead (TSP)a
Manganese (TSP)a
Nickel (TSP)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.0043
0.0000078
0.0024
0.00003
0.0018
0.000006
0.000011
0.000026
0.000013
0.00048
0.00000026
0.0000048
0.0000088
0.009
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
0.8
2.4
0.0098
0.00015
0.00005
0.00009
0.04
0.002
0.1
58/58
56/56
56/56
56/56
33/56
56/56
56/56
15/56
47/56
17/56
58/58
56/56
56/56
56/56
28/56
2/56
3/56
1.68
ฑ0.18
0.01
ฑ0.01
0.68
ฑ0.08
0.01
ฑO.01
0.04
ฑ0.01
O.01
ฑO.01
0.62
ฑ0.03
0.03
ฑ0.02
0.20
ฑ0.07
0.03
ฑ0.01
3.84
ฑ0.67
O.01
ฑO.01
0.01
ฑ0.01
O.01
ฑO.01
0.03
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
3.70
2.32
5.28
0.07
1.07
0.28
3.73
2.20
0.73
49.86
0.38
0.01
0.01
0.01
0.19
0.04
0.02
O.01
0.02
0.02
0.01
O.01
0.01
O.01
0.39
0.02
0.23
0.01
0.01
O.01
0.01
- = a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 19-5.
19-64
-------
Table 19-6. Risk Approximations for the Oklahoma Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Midwest City, Oklahoma - MWOK
Acetaldehyde
Acrylonitrile
Arsenic (TSP)a
Benzene
Beryllium (TSP)a
1,3 -Butadiene
Cadmium (TSP)a
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1,2-Dichloroethane
Ethylbenzene
Formaldehyde
Lead (TSP)a
Manganese (TSP)a
Nickel (TSP)a
Tetrachloroethylene
Trichloroethylene
0.0000022
0.000068
0.0043
0.0000078
0.0024
0.00003
0.0018
0.000006
0.000011
0.000026
0.0000025
0.000013
0.00048
0.00000026
0.0000048
0.009
0.002
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
0.8
2.4
1
0.0098
0.00015
0.00005
0.00009
0.04
0.002
56/56
5/56
56/56
56/56
56/56
40/56
56/56
56/56
23/56
50/56
9/56
56/56
56/56
56/56
56/56
56/56
40/56
1/56
2.03
ฑ0.24
0.01
ฑ0.01
<0.01
ฑ0.01
0.73
ฑ0.07
0.01
ฑ0.01
0.06
ฑ0.02
0.01
ฑ0.01
0.60
ฑ0.03
0.04
ฑ0.01
0.09
ฑ0.01
0.01
ฑ0.01
0.25
ฑ0.04
4.05
ฑ0.53
O.01
ฑ0.01
0.01
ฑ0.01
O.01
ฑ0.01
0.15
ฑ0.06
O.01
ฑO.01
4.47
0.76
1.71
5.73
0.05
1.81
0.22
3.60
0.99
0.39
0.61
52.69
0.58
0.04
0.01
0.23
0.01
0.03
0.02
0.01
0.03
0.01
0.01
0.01
O.01
0.01
O.01
0.41
0.02
0.27
0.01
0.01
O.01
- = a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 19-5.
19-65
-------
Table 19-6. Risk Approximations for the Oklahoma Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
# of Measured
Detections vs.
# of Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Oklahoma City, Oklahoma - OCOK
Acetaldehyde
Acrylonitrile
Arsenic (TSP)a
Benzene
Beryllium (TSP)a
1,3 -Butadiene
Cadmium (TSP)a
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1,2-Dichloroethane
Ethylbenzene
Formaldehyde
Lead (TSP)a
Manganese (TSP)a
Nickel (TSP)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0043
0.0000078
0.0024
0.00003
0.0018
0.000006
0.000011
0.000026
0.0000025
0.000013
0.00048
0.00000026
0.0000048
0.0000088
0.009
0.002
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
0.8
2.4
1
0.0098
0.00015
0.00005
0.00009
0.04
0.002
0.1
60/60
9/61
61/61
61/61
61/61
41/61
61/61
61/61
13/61
39/61
14/61
61/61
60/60
61/61
61/61
61/61
40/61
1/61
3/61
2.41
ฑ0.33
0.07
ฑ0.05
<0.01
ฑ0.01
0.88
ฑ0.21
0.01
ฑ0.01
0.20
ฑ0.31
0.01
ฑ0.01
0.58
ฑ0.04
0.02
ฑ0.01
0.06
ฑ0.01
0.03
ฑ0.02
0.31
ฑ0.04
4.06
ฑ0.80
O.01
ฑO.01
0.01
ฑ0.01
O.01
ฑO.01
0.08
ฑ0.02
O.01
ฑO.01
0.01
ฑ0.01
5.30
4.74
2.02
6.85
0.04
6.03
0.23
3.50
0.62
0.81
0.78
52.80
0.40
0.02
0.01
0.01
0.27
0.03
0.03
0.03
0.01
0.10
0.01
0.01
0.01
O.01
0.01
O.01
0.41
0.02
0.28
0.01
0.01
O.01
0.01
- = a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 19-5.
19-66
-------
Observations from Table 19-6 include the following:
Formaldehyde has the highest annual average concentration by mass for each site.
Among the TSP metals, the annual average concentration of manganese is the highest
for each site.
Formaldehyde and benzene have the highest cancer risk approximations among the
Oklahoma monitoring sites. Formaldehyde cancer risk approximations range from
48.62 in-a-million for TOOK to 52.80 in-a-million for OCOK. The cancer risk
approximations for OCOK and MWOK rank third and fourth highest among all
cancer risk approximations program-wide. Benzene cancer risk approximations range
from 5.28 in-a-million for PROK to 28.02 in-a-million for TOOK. The benzene
cancer risk approximation for TOOK is the highest benzene cancer risk
approximation program-wide.
Among the metals, arsenic has the highest cancer risk approximations for all of the
Oklahoma monitoring sites, ranging from 1.71 in-a-million for MWOK to
3.27 in-a-million for TOOK.
None of the pollutants of interest have noncancer hazard approximations greater than
1.0, indicating that no adverse health effects are expected from these individual
pollutants. Among the noncancer hazard approximations for the Oklahoma sites,
formaldehyde, manganese, and acetaldehyde have the highest noncancer hazard
approximations for each site (albeit less than 1.0).
19.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 19-7 and 19-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 19-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 19-6. Table 19-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 19-6.
19-67
-------
Table 19-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Oklahoma Monitoring Sites
OO
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Tulsa, Oklahoma (Tulsa County) - TOOK
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Tetrachloroethylene
Naphthalene
Dichloromethane
POM, Group 2b
Nickel, PM
398.15
236.92
198.13
105.13
52.47
41.33
23.57
5.51
3.59
0.40
Benzene
Formaldehyde
1,3 -Butadiene
Hexavalent Chromium, PM
Naphthalene
Ethylbenzene
POM, Group 2b
Acetaldehyde
POM, Group 3
Nickel, PM
3.11E-03
2.58E-03
1.57E-03
1.11E-03
8.02E-04
5.92E-04
3.16E-04
2.31E-04
2.30E-04
1.90E-04
Formaldehyde
Benzene
Acetaldehyde
Carbon Tetrachloride
Arsenic
1,3 -Butadiene
Ethylbenzene
ฃ>-Dichlorobenzene
Nickel
Cadmium
48.62
28.02
6.04
3.76
3.27
2.70
1.70
1.70
0.84
0.55
Tulsa, Oklahoma (Tulsa County) - TMOK
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Tetrachloroethylene
Naphthalene
Dichloromethane
POM, Group 2b
Nickel, PM
398.15
236.92
198.13
105.13
52.47
41.33
23.57
5.51
3.59
0.40
Benzene
Formaldehyde
1,3 -Butadiene
Hexavalent Chromium, PM
Naphthalene
Ethylbenzene
POM, Group 2b
Acetaldehyde
POM, Group 3
Nickel, PM
3.11E-03
2.58E-03
1.57E-03
1.11E-03
8.02E-04
5.92E-04
3.16E-04
2.31E-04
2.30E-04
1.90E-04
Formaldehyde
Benzene
Acrylonitrile
Acetaldehyde
Carbon Tetrachloride
1,3 -Butadiene
Arsenic
Ethylbenzene
ฃ>-Dichlorobenzene
Nickel
51.15
10.54
5.36
5.28
3.61
3.07
2.73
1.37
0.91
0.68
-------
Table 19-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Oklahoma Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Pryor Creek, Oklahoma (Mayes County) - PROK
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Chloromethylbenzene
Nickel, PM
Dichloromethane
Arsenic, PM
37.28
24.25
17.46
12.40
3.72
2.04
1.60
1.17
1.03
0.53
Arsenic, PM
Hexavalent Chromium, PM
Nickel, PM
Formaldehyde
Benzene
1,3 -Butadiene
Beryllium, PM
Cadmium, PM
Chloromethylbenzene
Naphthalene
2.29E-03
9.45E-04
5.62E-04
3.15E-04
2.91E-04
1.11E-04
8.46E-05
8.35E-05
7.85E-05
6.93E-05
Formaldehyde
Benzene
Carbon Tetrachloride
Acetaldehyde
Arsenic
ฃ>-Dichlorobenzene
1,3 -Butadiene
1 ,2-Dichloroethane
Nickel
Cadmium
49.86
5.28
3.73
3.70
2.32
2.20
1.07
0.73
0.38
0.28
Midwest City, Oklahoma (Oklahoma County) - MWOK
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
Tetrachloroethylene
POM, Group 2b
Bis(2-ethylhexyl)phthalate (DEHP), gas
447.79
275.02
250.63
137.04
59.70
29.28
15.08
10.79
4.51
0.49
Benzene
Formaldehyde
1,3 -Butadiene
Naphthalene
Ethylbenzene
Hexavalent Chromium, PM
POM, Group 2b
Acetaldehyde
POM, Group 3
Arsenic, PM
3.49E-03
3.26E-03
1.79E-03
9.96E-04
6.88E-04
6.16E-04
3.97E-04
3.01E-04
2.64E-04
1.85E-04
Formaldehyde
Benzene
Acetaldehyde
Carbon Tetrachloride
1,3 -Butadiene
Arsenic
ฃ>-Dichlorobenzene
Acrylonitrile
Ethylbenzene
Nickel
52.69
5.73
4.47
3.60
1.81
1.71
0.99
0.76
0.61
0.58
VO
-------
Table 19-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Oklahoma Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Oklahoma City, Oklahoma (Oklahoma County) - OCOK
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
Tetrachloroethylene
POM, Group 2b
Bis(2-ethylhexyl)phthalate (DEHP), gas
447.79
275.02
250.63
137.04
59.70
29.28
15.08
10.79
4.51
0.49
Benzene
Formaldehyde
1,3 -Butadiene
Naphthalene
Ethylbenzene
Hexavalent Chromium, PM
POM, Group 2b
Acetaldehyde
POM, Group 3
Arsenic, PM
3.49E-03
3.26E-03
1.79E-03
9.96E-04
6.88E-04
6.16E-04
3.97E-04
3.01E-04
2.64E-04
1.85E-04
Formaldehyde
Benzene
1,3 -Butadiene
Acetaldehyde
Acrylonitrile
Carbon Tetrachloride
Arsenic
1 ,2-Dichloroethane
Ethylbenzene
/>-Dichlorobenzene
52.80
6.85
6.03
5.30
4.74
3.50
2.02
0.81
0.78
0.62
-------
Table 19-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Oklahoma Monitoring Sites
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer
Hazard
Approximation
(HQ)
Tulsa, Oklahoma (Tulsa County) - TOOK
Toluene
Xylenes
Methanol
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Ethylene glycol
1,180.06
902.52
402.45
398.15
293.67
236.92
198.13
105.13
52.47
50.77
Acrolein
1,3 -Butadiene
Formaldehyde
Manganese, PM
Benzene
Lead, PM
Acetaldehyde
Xylenes
Naphthalene
Cobalt , PM
577,473.50
26,235.74
20,217.32
18,832.62
13,271.68
13,200.35
11,681.56
9,025.21
7,857.87
5,351.77
Manganese
Formaldehyde
Acetaldehyde
Benzene
Propionaldehyde
Arsenic
1,3 -Butadiene
Lead
Cadmium
Nickel
0.60
0.38
0.31
0.12
0.06
0.05
0.05
0.04
0.03
0.02
Tulsa, Oklahoma (Tulsa County) - TMOK
Toluene
Xylenes
Methanol
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Ethylene glycol
1,180.06
902.52
402.45
398.15
293.67
236.92
198.13
105.13
52.47
50.77
Acrolein
1,3 -Butadiene
Formaldehyde
Manganese, PM
Benzene
Lead, PM
Acetaldehyde
Xylenes
Naphthalene
Cobalt , PM
577,473.50
26,235.74
20,217.32
18,832.62
13,271.68
13,200.35
11,681.56
9,025.21
7,857.87
5,351.77
Manganese
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Benzene
Arsenic
Acrylonitrile
Lead
Cadmium
Nickel
0.41
0.40
0.27
0.05
0.05
0.04
0.04
0.03
0.02
0.02
-------
Table 19-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Oklahoma Monitoring Sites (Continued)
to
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer
Hazard
Approximation
(HQ)
Pryor Creek, Oklahoma (Mayes County) - PROK
Hydrochloric acid
Toluene
Xylenes
Benzene
Cyanide Compounds, gas
Hydrofluoric acid
Formaldehyde
Methanol
Hexane
Ethylbenzene
145.18
89.08
72.70
37.28
34.90
26.35
24.25
23.55
22.30
17.46
Acrolein
Chlorine
Cyanide Compounds, gas
Arsenic, PM
Nickel, PM
Manganese, PM
Hydrochloric acid
Cyanide Compounds, PM
Cadmium, PM
Lead, PM
91,374.65
61,006.67
43,619.17
35,508.85
13,015.34
8,604.28
7,259.15
7,154.96
4,636.70
4,369.13
Formaldehyde
Manganese
Acetaldehyde
Arsenic
Benzene
Lead
1,3 -Butadiene
Cadmium
Nickel
Carbon Tetrachloride
0.39
0.23
0.19
0.04
0.02
0.02
0.02
0.02
0.01
0.01
Midwest City, Oklahoma (Oklahoma County) - MWOK
Toluene
Xylenes
Methanol
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
1,373.20
1,058.17
468.16
447.79
337.57
275.02
250.63
137.04
61.51
59.70
Acrolein
1,3 -Butadiene
Formaldehyde
Acetaldehyde
Benzene
Xylenes
Naphthalene
Arsenic, PM
Lead, PM
Propionaldehyde
875,997.95
29,851.09
25,574.80
15,226.70
14,926.42
10,581.67
9,759.95
2,874.57
2,417.07
2,079.24
Formaldehyde
Manganese
Acetaldehyde
1,3 -Butadiene
Arsenic
Benzene
Lead
Nickel
Cadmium
Carbon Tetrachloride
0.41
0.27
0.23
0.03
0.03
0.02
0.02
0.01
0.01
0.01
-------
Table 19-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Oklahoma Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer
Hazard
Approximation
(HQ)
Oklahoma City, Oklahoma (Oklahoma County) - OCOK
Toluene
Xylenes
Methanol
Benzene
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
1,373.20
1,058.17
468.16
447.79
337.57
275.02
250.63
137.04
61.51
59.70
Acrolein
1,3 -Butadiene
Formaldehyde
Acetaldehyde
Benzene
Xylenes
Naphthalene
Arsenic, PM
Lead, PM
Propionaldehyde
875,997.95
29,851.09
25,574.80
15,226.70
14,926.42
10,581.67
9,759.95
2,874.57
2,417.07
2,079.24
Formaldehyde
Manganese
Acetaldehyde
1,3 -Butadiene
Acrylonitrile
Arsenic
Benzene
Lead
Cadmium
Nickel
0.41
0.28
0.27
0.10
0.03
0.03
0.03
0.02
0.01
0.01
-------
The pollutants listed in Tables 19-7 and 19-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 19.3, the Oklahoma sites sampled VOCs, carbonyl compounds, and TSP metals. In
addition, the cancer risk and noncancer hazard approximations are limited to those pollutants
with enough data to meet the criteria for annual averages to be calculated, as discussed in
previous sections. A more in-depth discussion of this analysis is provided in Section 3.5.5.3.
Similar to the cancer risk and noncancer hazard approximations, this analysis may help policy-
makers prioritize their air monitoring activities.
Observations from Table 19-7 include the following:
Benzene is the highest emitted pollutant with a cancer URE in Mayes, Oklahoma, and
Tulsa Counties, followed by ethylbenzene and formaldehyde in Oklahoma and Tulsa
Counties and formaldehyde and ethylbenzene in Mayes County. The emissions of
these pollutants in Mayes County are an order of magnitude lower than the emissions
for Oklahoma and Tulsa Counties.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
cancer UREs) for Oklahoma and Tulsa Counties are benzene, formaldehyde, and
1,3-butadiene. The pollutants with the highest toxicity-weighted emissions for Mayes
County are arsenic, hexavalent chromium, and nickel.
Eight of the highest emitted pollutants in Tulsa County also have the highest toxicity-
weighted emissions. Six of the highest emitted pollutants in Mayes County also have
the highest toxicity-weighted emissions. Seven of the highest emitted pollutants in
Oklahoma County also have the highest toxicity-weighted emissions.
Formaldehyde and benzene have the highest cancer risk approximations among the
Oklahoma sites' pollutants of interest. These pollutants appear on both emissions-
based lists for all five sites. Conversely, carbon tetrachloride, another pollutant with
relatively high cancer risk approximations, does not appear on either emissions-based
list.
While hexavalent chromium is among the pollutants with the highest toxicity-
weighted emissions for each county, it is not among the highest emitted pollutants.
This indicates that lower emissions can translate to higher risk levels.
The toxicity-weighted pollutants listed for Mayes County are considerably different
than for the other two counties. There are five metals listed for Mayes County while
the other counties only have two each. In addition, there are no POM Groups listed
19-74
-------
for Mayes County, while POM, Groups 2b and 3 appear for Oklahoma and Tulsa
Counties.
Observations from Table 19-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in Oklahoma and Tulsa Counties. Hydrochloric acid, toluene, and xylenes are
the highest emitted pollutants with noncancer RfCs in Mayes County. Note that the
quantity emitted is much higher in Tulsa and Oklahoma Counties than in Mayes
County.
Acrolein is the pollutant with the highest toxi city-weighted emissions (of the
pollutants with noncancer RfCs) for all three counties. Yet, this pollutant is not
among the highest emitted pollutants for any of the three counties. This indicates that
lower emissions can translate to higher risk levels. Acrolein was sampled for at all of
the Oklahoma sites, but this pollutant was excluded from the pollutants of interest
designation, and thus subsequent risk-based screening evaluations, due to questions
about the consistency and reliability of the measurements, as discussed in Section 3.2.
Two of the highest emitted pollutants in Mayes County also have the highest toxicity-
weighted emissions; five of the highest emitted pollutants in Tulsa and Oklahoma
Counties also have the highest toxicity-weighted emissions.
Five of the 10 pollutants with the highest noncancer toxicity-weighted emissions in
Mayes County were metals. Cyanide compounds, gaseous and particulate, account for
two more.
Formaldehyde and manganese have the highest noncancer hazard approximations
among the Oklahoma sites. Formaldehyde appears on both emissions-based lists for
Tulsa and Oklahoma Counties but ranks 111 for toxicity-weighted emissions for
Mayes County and therefore does not appear in Table 19-8 in that column.
Manganese appears among the pollutants with the highest toxicity-weighted
emissions for Tulsa and Mayes Counties but ranks 14th for toxicity-weighted
emissions for Oklahoma County. There are no metals listed among the highest
emitted pollutants for any of the three counties.
It is important to note that for the metals, the emissions-based lists are PMi0 while the
Oklahoma sites sampled TSP metals.
19.6 Summary of the 2011 Monitoring Data for the Oklahoma Monitoring Sites
Results from several of the data treatments described in this section include the
following:
ปซป Twenty pollutants failed at least one screen for TOOK; 19 pollutants failed screens
for TMOK; 15 pollutants failed screens for PROK; 17 pollutants failed screens for
MWOK; and 16 pollutants failed screens for OCOK.
19-75
-------
Formaldehyde had the highest annual average concentration by mass for each site.
Among the TSP metals, the annual average concentration of manganese was the
highest for each site.
TOOK had the highest annual average of concentration of benzene among all NMP
sites sampling this pollutant. Annual averages of formaldehyde for all five Oklahoma
sites rank among the highest annual average concentrations of formaldehyde
program-wide.
Concentrations of several of the NATTSMQO Core Analytes exhibit increasing
trends at TOOK.
19-76
-------
20.0 Site in Rhode Island
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Rhode Island, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
20.1 Site Characterization
This section characterizes the Rhode Island monitoring site by providing geographical
and physical information about the location of the site and the surrounding area. This
information is provided to give the reader insight regarding factors that may influence the air
quality near the site and assist in the interpretation of the ambient monitoring measurements.
The PRRI monitoring site is located in south Providence. Figure 20-1 is a composite
satellite image retrieved from ArcGIS Explorer showing the monitoring site in its urban location.
Figure 20-2 identifies nearby point source emissions locations by source category, as reported in
the 2008 NEI for point sources. Note that only sources within 10 miles of the site are included in
the facility counts provided in Figure 20-2. A 10-mile boundary was chosen to give the reader an
indication of which emissions sources and emissions source categories could potentially have a
direct effect on the air quality at the monitoring site. Further, this boundary provides both the
proximity of emissions sources to the monitoring site as well as the quantity of such sources
within a given distance of the site. Sources outside the 10-mile radius are still visible on the map,
but have been grayed out in order to show emissions sources just outside the boundary.
Table 20-1 provides supplemental geographical information such as land use, location setting,
and locational coordinates.
20-1
-------
Figure 20-1. Providence, Rhode Island (PRRI) Monitoring Site
to
o
-------
Figure 20-2. NEI Point Sources Located Within 10 Miles of PRRI
Legend
7V SO'fTW 71 "KWVf 71
Note: Due to faculty density and collocation, the total facilities
displayed may nol ropjcsont all facilities within the area of interest
PRRI NATTS site 10 mile radius
County boundary
Source Category Group (No. of Facilities)
H^ Aircran Operations (13)
$3 Automobile/Truck Manufacturing (2)
ฃ Battery (2)
ฃ Boat Manufacturing (1)
C Chemical Manufacturing {7}
Concrete Batch Plant (2)
X Crematory -Animal/Human (1)
(D Dry Cleaning Facility (37)
6 Eleclncal Equipment (4)
ฃ Eleclncity Gerseralion via Combustion (4)
E Electroplating. Plating, Polishing, Anodizing & Coloring (24)
<> Fabricated Metal Products (25)
id> Flexible Polyurethane Foam Production (I >
F Food Processing/Agncullure {4)
[T] Furniture Plani (2)
jf Gasolinej'Diesel Service Station (4)
fV Glass Manufacturing (1)
(3 Hospital (3)
J| Hot Mix Asphalt Plant (4)
-^ Industnal Machinery and Equipment (5)
^ In stilutional - school (11)
A LandMI (1i
? Miscellaneous Commercial/Industrial {21}
M Miscellaneous Manufacturing (45)
4 Oil and/or Gas Production 11)
-. Pharmaceutical Manufacturing (1)
1 Primary Metal Production (6)
P Printing/Publishing (11)
El PulP and Paper Plant/Wood Products (4)
R Rubber and Miscellaneous Plastics Products (10)
< Site Remediation Activity (1 >
S Surface Coaling (3)
TT Telecommuntcatjons (4)
T Textile Mril (12)
I V&stewater Treatment (1)
W Waochvork Furmlure Milhvork & Wood Preserving (1)
20-3
-------
Table 20-1. Geographical Information for the Rhode Island Monitoring Site
Site
Code
PRRI
AQS Code
44-007-0022
Location
Providence
County
Providence
Micro- or
Metropolitan
Statistical Area
Providence-New
Bedford-Fall
River, RI-MA
MSA
Latitude
and
Longitude
41.807949,
-71.415
Land Use
Residential
Location
Setting
Urban/City
Center
Additional Ambient Monitoring Information1
PAMS, VOCs, Carbonyl Compounds, Meteorological
parameters, PM10, PM10 Speciation, Black Carbon,
PM2 5, and PM2 5 Speciation, Germanium.
1 Data for additional pollutants are reported to AQS for PRRI (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this report.
BOLD ITALICS = EPA-designaled NATTS Site
to
o
-------
Figure 20-1 shows that the areas to the west and south of PRRI are residential, but areas
to the north and east are commercial. A hospital lies to the northeast of the site, just north of
Dudley Street. About 1/2 mile to the east 1-95 runs north-south, then turns northwestward,
entering downtown Providence. Narragansett Bay and the Port of Providence are a few tenths of
a mile farther to the east, just on the other side of 1-95. Figure 20-2 shows that a large number of
point sources are located within 10 miles of PRRI, especially to the north of the site. Many of
these sources seem to parallel 1-95. The source categories with the greatest number of point
sources within 10 miles of PRRI include dry cleaners; fabricated metals products facilities;
electroplating, plating, polishing, anodizing, and coloring facilities; and aircraft operations,
which includes airports as well as small runways, heliports, or landing pads.
Table 20-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Rhode Island monitoring site. Table 20-2 includes a county-level
population for the site. County-level vehicle registration data for Providence County were not
available from the State of Rhode Island. Thus, state-level vehicle registration, which was
obtained from the Federal Highway Administration, was allocated to the county level using the
county-level proportion of the state population from the U.S. Census Bureau. Table 20-2 also
includes a county-level vehicle registration-to-population ratio, which was calculated to
represent the number of vehicles per person within the monitoring site's residing county. In
addition, the population within 10 miles of the site is presented, based on postal code population
data estimates. An estimate of 10-mile vehicle ownership was then determined by applying the
county-level vehicle registration-to-population ratio to the 10-mile population surrounding the
monitoring site. Table 20-2 also contains traffic volume information for PRRI. County-level
VMT data were not readily available for Providence County.
20-5
-------
Table 20-2. Population, Motor Vehicle, and Traffic Information for the Rhode Island
Monitoring Site
Site
PRRI
Estimated
County
Population1
626,709
County-level
Vehicle
Registration2
485,837
Vehicles per
Person
(Registration:
Population)
0.78
Population
within 10
miles3
657,586
Estimated
10-mile
Vehicle
Ownership
509,773
Annual
Average
Daily
Traffic4
136,800
County-
level Daily
VMT5
~
1 County -level population estimate reflects 20 1 1 data from the U. S. Census Bureau (Census Bureau, 20 12b)
2County-level vehicle registration reflects a ratio based on 2010 state-level vehicle registration data from the
FHWAandthe 2010 county -level proportion of the state population data (FHW A, 2011 and Census Bureau, 2011)
3 10-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2009 data from the Rhode Island DOT (RI DOT, 2009)
5County -level VMT was not available for this site.
BOLD ITALICS = EPA-de signaled NATTS Site
Observations from Table 20-2 include the following:
Providence County's population is in the middle of the range compared to other
counties with NMP sites, as is the 10-mile population.
The estimated county-level vehicle registration is in the middle of the range compared
to other counties with NMP sites, as is the 10-mile ownership estimate.
The vehicle-per-person ratio is in the bottom third compared to other NMP sites.
The traffic volume experienced near PRRI is the ninth highest compared to other
NMP monitoring sites. The traffic estimate provided is for 1-95 near the 1-195
interchange.
20.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Rhode Island on sample days, as well as over the course of the year.
20.2.1 Climate Summary
Providence is a coastal city on the Narragansett Bay, which opens to the Rhode Island
Sound and the Atlantic Ocean. The city's proximity to the Sound and the Atlantic Ocean temper
cold air outbreaks, and breezes off the ocean moderate summertime heat. On average, southerly
and southwesterly winds in the summer become northwesterly in the winter. Precipitation in
Providence is well distributed throughout the year. Weather is fairly variable as frequent storm
systems affect the New England region (Bair, 1992).
20-6
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20.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest PRRI were retrieved
for 2011 (NCDC, 2011). The closest weather station is located at Theodore F. Green State
Airport (WBAN 14765). Additional information about the T.F. Green weather station, such as
the distance between the site and the weather station, is provided in Table 20-3. These data were
used to determine how meteorological conditions on sample days vary from conditions
experienced throughout the year.
Table 20-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 20-3 is the 95 percent
confidence interval for each parameter. As shown in Table 20-3, average meteorological
conditions on sample days appear slightly cooler than average weather conditions throughout the
year, although the differences are not statistically significant. This is likely the result of several
make-up samples collected during the first quarter of the year.
20.2.3 Back Trajectory Analysis
Figure 20-3 is the composite back trajectory map for days on which samples were
collected at the PRRI monitoring site in 2011. Included in Figure 20-3 are four back trajectories
per sample day. Figure 20-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 20-3 and 20-4 represents 100 miles.
20-7
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to
o
oo
Table 20-3. Average Meteorological Conditions near the Rhode Island Monitoring Site
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Providence, Rhode Island - PRRI
Theodore F.
Green State
Airport
14765
(41.72, -71.43)
6.01
miles
173ฐ
(S)
Sample
Day
2011
59.5
ฑ4.3
60.9
+ 1.8
51.3
ฑ4.1
52.6
+ 1.8
40.2
ฑ4.7
41.9
+ 1.9
46.4
ฑ4.0
47.7
+ 1.7
69.0
ฑ3.8
69.9
+ 1.5
1014.9
ฑ2.0
1015.4
+ 0.8
7.6
ฑ0.7
7.0
+ 0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Figure 20-3. 2011 Composite Back Trajectory Map for PRRI
Figure 20-4. Back Trajectory Cluster Map for PRRI
20-9
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Observations from Figures 20-3 and 20-4 for PRRI include the following:
Back trajectories originated from a variety of directions at PRRI, although the
majority of back trajectories originated from the northwest to north and south-
southeast to south-southwest.
The airshed domain for PRRI was among the larger in size compared to other NMP
sites, based on the average trajectory length. The average trajectory length was
265 miles long, although the farthest away a back trajectory originated was off the
North Carolina coast and over the Atlantic Ocean, or greater than 600 miles away.
However, 87 percent of back trajectories originating within 450 miles of the site.
The cluster analysis shows that nearly 50 percent of back trajectories originated from
the west, northwest, and north, although of differing lengths, as represented by three
cluster trajectories. One originates over south Ontario, Canada (11 percent) and
represents longer trajectories originating over the Great Lakes region. The short
cluster trajectory originating over New York (16 percent) represents back trajectories
originating over northern New York, Vermont, and New Hampshire as well as shorter
northward originating trajectories. The cluster trajectory originating to the north
(20 percent) represents longer trajectories originating over Quebec, Canada, as well
as shorter back trajectories originating over Maine and the Gulf of Maine. Twenty-
nine percent of back trajectories originated to the southwest of PRRI, although this
cluster trajectory also represents short back trajectories (generally 100-200 miles in
length) originating from the south to southwest to west of the site. Twelve percent of
back trajectories originated over the offshore waters of the Mid-Atlantic states, while
another 12 percent originated from a direction with an easterly component.
20.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at T.F. Green Airport near PRRI
were uploaded into a wind rose software program to produce customized wind roses, as
described in Section 3.5.2.2. A wind rose shows the frequency of wind directions using "petals"
positioned around a 16-point compass, and uses different colors to represent wind speeds.
Figure 20-5 presents a map showing the distance between the NWS station and PRRI,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 20-5 also presents three different wind roses for the
PRRI monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
20-10
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determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
Observations from Figure 20-5 for PRRI include the following:
The NWS weather station at T.F. Green Airport is located approximately 6 miles
south of PRRI.
The historical wind rose shows that while westerly winds were observed the most
(approximately 12 percent of observations), winds from the western quadrants, due
north, and due south are common near PRRI. Calm winds (< 2 knots) account for less
than nine percent of the hourly measurements.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, with winds from the western quadrants, due north, and due south prevalent
near PRRI, although there are some slight differences in the percentages. Also, the
calm rate for 2011 is nearly 12 percent, which is slightly higher than the calm rate for
the historical wind rose.
The wind patterns shown on the sample day wind rose continue the prevalence of
winds from the western quadrants and due north and due south, although the
percentages vary for some directions. The sample day calm rate is similar to the full-
year calm rate. These similarities indicate that conditions on sample days were
generally representative of conditions experienced throughout the year and
historically.
20-11
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Figure 20-5. Wind Roses for the T.F. Green State Airport Weather Station near PRRI
Distance between PRRI and NWS Station
2001-2010 Historical Wind Rose
.'VEST
2011 Wind Rose
Sample Day Wind Rose
WEST
20-12
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20.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Rhode Island monitoring
site in order to allow analysts and readers to focus on a subset of pollutants through the context
of risk. Each pollutant's preprocessed daily measurement was compared to its associated risk
screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by the monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 20-4 presents the results of the preliminary risk-based screening process for PRRI.
The pollutants that failed at least one screen and contributed to 95 percent of the total failed
screens for PRRI are shaded. NATTS MQO Core Analytes are bolded. Thus, pollutants of
interest are shaded and/or bolded. PRRI sampled for PAHs and hexavalent chromium.
Table 20-4. Risk-Based Screening Results for the Rhode Island Monitoring Site
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Providence, Rhode Island - PRRI
Naphthalene
Fluorene
Acenaphthene
Fluoranthene
Hexavalent Chromium
0.029
0.011
0.011
0.011
0.000083
Total
57
4
3
1
1
66
57
57
57
57
52
280
100.00
7.02
5.26
1.75
1.92
23.57
86.36
6.06
4.55
1.52
1.52
86.36
92.42
96.97
98.48
100.00
Observations from Table 20-4 include the following:
Five pollutants failed screens for PRRI. Naphthalene failed 100 percent of its screens
and accounted for 86 percent of PRRI's total failed screens.
Naphthalene, fluorene, and acenaphthene were identified as the pollutants of interest
for PRRI based on the risk-based screening process. Hexavalent chromium was added
to the pollutants of interest for PRRI because is it a NATTS MQO Core Analyte, even
though it did not contribute to 95 percent of failed screens. Benzo(a)pyrene was
added to the pollutants of interest for PRRI because it is also a NATTS MQO Core
20-13
-------
Analyte, even though it did not fail any screens. Benzo(a)pyrene is not shown in
Table 20-4 but is shown in subsequent tables in the sections that follow.
20.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Rhode Island monitoring site. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest for PRRI, where the data meet the applicable criteria.
Concentration averages for select pollutants are also presented graphically for the site to
illustrate how the site's concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for PRRI are provided in Appendices M and O.
20.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for the Rhode Island site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for PRRI are presented in
Table 20-5, where applicable. Note that if a pollutant was not detected in a given calendar
quarter, the quarterly average simply reflects "0" because only zeros substituted for non-detects
were factored into the quarterly average concentration.
20-14
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Table 20-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Rhode Island Monitoring Site
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Providence, Rhode Island - PRRI
Acenaphthene
Benzo(a)pyrene
Fluorene
Hexavalent Chromium
Naphthalene
57/57
56/57
57/57
52/57
57/57
1.39
ฑ0.30
0.20
ฑ0.07
2.78
ฑ0.50
0.02
ฑ0.01
84.66
ฑ 22.05
4.35
ฑ1.60
0.17
ฑ0.06
5.97
ฑ2.25
0.02
ฑ0.01
70.92
ฑ 20.09
6.61
ฑ2.06
0.10
ฑ0.03
8.13
ฑ2.24
0.03
ฑ0.02
108.89
ฑ38.22
2.33
ฑ0.79
0.16
ฑ0.06
3.13
ฑ0.74
0.02
ฑ0.01
100.52
ฑ 32.64
3.65
ฑ0.83
0.16
ฑ0.03
4.97
ฑ0.96
0.02
ฑ0.01
91.41
ฑ 14.27
Observations for PRRI from Table 20-5 include the following:
The annual average concentration of naphthalene is significantly higher than the
annual averages of the other pollutants of interest.
Although the third and fourth quarter average concentrations of naphthalene are
higher than the other quarterly averages, the associated confidence intervals indicate
that there is a high level of variability associated with the naphthalene concentrations.
Naphthalene measurements range from 29.7 ng/m3 to 277 ng/m3, with a median
concentration of 78.5 ng/m3. Of the six concentrations of naphthalene greater than
150 ng/m3, one was measured in February, one in July, two in August, and two in
November. The minimum concentration of naphthalene was also measured in
November.
Concentrations of acenaphthene and fluorene are highest during the warmer months
of the year, as indicated by the second and third quarter averages, although they have
relatively high levels of variability associated with them. The 11 concentrations of
fluorene greater than 7 ng/m3 were all measured between May and August, while the
20 concentrations less than 3 ng/m3 were measured between January and April or
October and December. A similar trend is exhibited by the acenaphthene
measurements.
Although the annual average benzo(a)pyrene concentration is relatively low
compared to the other pollutants of interest for PRRI, this annual average is the fourth
highest annual average benzo(a)pyrene concentration among sites sampling PAHs, as
shown in Table 4-11.
20-15
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20.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots were created for
benzo(a)pyrene, hexavalent chromium, and naphthalene for PRRI. Figures 20-6 through 20-8
overlay the site's minimum, annual average, and maximum concentrations onto the program-
level minimum, first quartile, median, average, third quartile, and maximum concentrations, as
described in Section 3.5.3.
Figure 20-6. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
PRRI
3.25
3.5
0.75 1
Concentration (
1.25
1.5
1.75
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 20-7. Program vs. Site-Specific Average Hexavalent Chromium Concentration
PRRI
I
0.05
0.1
0.15
Concentration (ng/m3)
0.2
DL25
3.3
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
20-16
-------
Figure 20-8. Program vs. Site-Specific Average Naphthalene Concentration
PRRI
i Program Max Concentration = 779 ng/m3
50
100
is:
200 Z50 300
Concentration (ng/m3)
= 50
400
453
555
Program: IstQuartile 2ndQuartile 3rd Quartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
Observations from Figures 20-6 through 20-8 include the following:
Figure 20-6 is the box plot for benzo(a)pyrene. Note that the program-level first
quartile for this pollutant is zero and is not visible on the box plot. This box plot
shows that the annual average concentration for PRRI is greater than the program-
level average concentration. The maximum concentration measured at PRRI is
considerably less than the maximum concentration measured across the program.
A single non-detect of benzo(a)pyrene was measured at PRRI.
Figure 20-7 is the box plot for hexavalent chromium. The annual average
concentration of hexavalent chromium for PRRI is just less than the program-
level average but greater than program-level median concentration. The maximum
concentration measured at PRRI is less than the program-level maximum
concentration, although the maximum hexavalent chromium concentration for
PRRI is the ninth highest concentration measured among NMP sites sampling this
pollutant. There were five non-detects of hexavalent chromium measured at
PRRI.
Figure 20-8 is the box plot for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot
because the scale of the box plot would be too large to readily observe data points
at the lower end of the concentration range. Thus, the scale has been reduced to
500 ng/m3. Figure 20-8 shows that the annual average naphthalene concentration
for PRRI is greater than the program-level average concentration. The maximum
naphthalene concentration measured at PRRI is less than the maximum
concentration measured at the program-level while the minimum concentration
measured at PRRI is just less than the program-level first quartile. There were no
non-detects of naphthalene measured at PRRI.
20-17
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20.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. PRRI has sampled hexavalent chromium under the NMP since 2005. Thus,
Figure 20-9 presents the annual statistical metrics for hexavalent chromium for PRRI. The
statistical metrics presented for assessing trends include the substitution of zeros for non-detects.
A trends analysis was not performed for the PAHs because PAH sampling did not begin at PRRI
until 2008.
Figure 20-9. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at PRRI
2008
Year
- Minimum
- Maximum
* 95thPercentile
Average
Observations from Figure 20-9 for hexavalent chromium measurements at PRRI include
the following:
The maximum hexavalent chromium concentration was measured on
August 28, 2007 (0.193 ng/m3), although a similar concentration was also measured
on July 4, 2006 (0.192 ng/m3). The third highest concentration was measured in 2011
(July 20, 2011,0.147 ng/m3).
20-18
-------
The average concentration of hexavalent chromium has fluctuated over the years of
sampling, with the average at a maximum in 2006 (0.027 ng/m3) and a minimum in
2009 (0.007 ng/m3). However, an increasing trend is shown over the last two year
years of sampling.
For each year shown, the minimum and 5th percentile are zero, indicating the presence
of non-detects. The number of non-detects reported has varied by year, from as low as
nine percent in 2011 to as high as 65 percent in 2009. This explains why the median
concentration is also zero for 2009.
20.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
PRRI monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations regarding
the various toxicity factors, time frames, and calculations associated with these risk-based
screenings.
20.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Rhode Island monitoring site to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
20.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Rhode Island monitoring site and where annual
average concentrations could be calculated, risk was examined by calculating cancer risk and
noncancer hazard approximations. These approximations can be used as risk estimates for cancer
and noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
20-19
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confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 20-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
Table 20-6. Risk Approximations for the Rhode Island Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Providence, Rhode Island - PRRI
Acenaphthene
Benzo(a)pyrene
Fluorene
Hexavalent Chromium
Naphthalene
0.000088
0.00176
0.000088
0.012
0.000034
0.0001
0.003
57/57
56/57
57/57
52/57
57/57
3.65
ฑ0.83
0.16
ฑ0.03
4.97
ฑ0.96
0.02
ฑ0.01
91.41
ฑ 14.27
0.32
0.28
0.44
0.27
3.11
O.01
0.03
= a Cancer URE or Noncancer RfC is not available
Observations for PRRI from Table 20-6 include the following:
As discussed in the previous section, naphthalene has the highest annual average
concentration among the pollutants of interest for PRRI, followed by fluorene and
acenaphthene.
The cancer risk approximation for naphthalene (3.11 in-a-million) is the highest
cancer risk approximation among the pollutants of interest for PRRI and the only
cancer risk approximation greater than 1-in-a-million.
Only two of the five pollutants of interest for PRRI have noncancer RfCs (hexavalent
chromium and naphthalene).The noncancer hazard approximations for naphthalene
and hexavalent chromium are negligible (0.03 in-a-million and <0.01 in-a-million,
respectively), indicating that no adverse health effects are expected from these
individual pollutants.
20-20
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20.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 20-7 and 20-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 20-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 20-6. Table 20-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations, also calculated from annual averages provided in
Table 20-6.
The pollutants listed in Tables 20-7 and 20-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on the site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 20.3, PRRI sampled for PAHs and hexavalent chromium only. In addition, the cancer
risk and noncancer hazard approximations are limited to those pollutants with enough data to
meet the criteria for annual averages to be calculated. A more in-depth discussion of this analysis
is provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations,
this analysis may help policy-makers prioritize their air monitoring activities.
20-21
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Table 20-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer
UREs for the Rhode Island Monitoring Site
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Providence, Rhode Island (Providence County) - PRRI
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Tetrachloroethylene
Naphthalene
Dichloromethane
Trichloroethylene
POM, Group 2b
204.49
155.91
96.49
84.05
30.18
27.44
17.46
8.03
6.19
4.97
Formaldehyde
Benzene
POM, Group 3
1,3 -Butadiene
Naphthalene
POM, Group 2b
Hexavalent Chromium, PM
POM, Group 5a
Ethylbenzene
Arsenic, PM
2.03E-03
1.60E-03
1.18E-03
9.05E-04
5.93E-04
4.37E-04
3.47E-04
2.51E-04
2.41E-04
1.98E-04
Naphthalene
Fluorene
Acenaphthene
Benzo(a)pyrene
Hexavalent Chromium
3.11
0.44
0.32
0.28
0.27
to
o
to
to
-------
Table 20-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with
Noncancer RfCs for the Rhode Island Monitoring Site
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Providence, Rhode Island (Providence County) - PRRI
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
576.48
398.70
368.54
204.49
155.91
128.27
96.49
84.05
38.49
30.18
Acrolein
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Benzene
Naphthalene
Xylenes
Nickel, PM
Trichloroethylene
Arsenic, PM
335,397.31
15,908.87
15,090.50
9,339.31
6,816.26
5,818.50
3,986.98
3,977.28
3,096.76
3,072.81
Naphthalene 0.03
Hexavalent Chromium O.01
to
o
to
-------
Observations from Table 20-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Providence County.
Formaldehyde is also the pollutant with the highest toxicity-weighted emissions (of
the pollutants with cancer UREs), followed by benzene and POM, Group 3.
Six of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Providence County.
Naphthalene, which has the highest cancer risk approximation among the pollutants
of interest for PRRI, has the seventh highest emissions and the fifth highest toxicity-
weighted emissions.
POM, Group 2b is the tenth highest emitted "pollutant" in Providence County and
ranks sixth for toxicity-weighted emissions. POM, Group 2b includes several PAHs
sampled for at PRRI including acenaphthene, fluoranthene, and fluorene, all of which
failed at least one screen for PRRI.
POM, Group 5a ranks eighth for toxicity-weighted emissions. POM, Group 5a
includes benzo(a)pyrene, another pollutant of interest for PRRI. POM, Group 5a is
not among the highest emitted "pollutants" in Providence County.
Hexavalent chromium, which is also one of the pollutants of interest for PRRI, has
the seventh highest toxicity-weighted emissions for Providence County, but does not
appear among the highest emitted pollutants.
Observations from Table 20-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in Providence County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, formaldehyde, and 1,3-butadiene.
Five of the highest emitted pollutants in Providence County also have the highest
toxicity-weighted emissions.
While naphthalene ranks sixth among the pollutants with the highest toxicity-
weighted emissions, it is not one of the highest emitted pollutants (with a noncancer
RfC) in Providence County. Hexavalent chromium does not appear on either
emissions-based list. These are the only two pollutants of interest with noncancer
RfCs for PRRI.
20-24
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20.6 Summary of the 2011 Monitoring Data for PRRI
Results from several of the data treatments described in this section include the
following:
ปซป Five pollutants failed at least one screen for PRRI, with naphthalene accounting for
the majority of the failed screens.
*ป* Of the site-specific pollutants of the interest, naphthalene had the highest annual
average concentration for PRRI.
ปซป Concentrations ofhexavalent chromium have an increasing trend for the most recent
years of sampling at PRRI.
20-25
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21.0 Site in South Carolina
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in South Carolina, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
21.1 Site Characterization
This section characterizes the South Carolina monitoring site by providing geographical
and physical information about the location of the site and the surrounding area. This
information is provided to give the reader insight regarding factors that may influence the air
quality near the site and assist in the interpretation of the ambient monitoring measurements.
CHSC is located in central Chesterfield County, South Carolina. Figure 21-1 is a
composite satellite image retrieved from ArcGIS Explorer showing the monitoring site in its
rural location. Figure 21-2 identifies nearby point source emissions locations by source category,
as reported in the 2008 NEI for point sources. Note that only sources within 10 miles of the site
are included in the facility counts provided in Figure 21-2. A 10-mile boundary was chosen
to give the reader an indication of which emissions sources and emissions source categories
could potentially have a direct effect on the air quality at the monitoring site. Further, this
boundary provides both the proximity of emissions sources to the monitoring site as well as the
quantity of such sources within a given distance of the site. Sources outside the 10-mile radius
are still visible on the map, but have been grayed out in order to show emissions sources just
outside the boundary. Table 21-1 provides supplemental geographical information such as land
use, location setting, and locational coordinates.
21-1
-------
Figure 21-1. Chesterfield, South Carolina (CHSC) Monitoring Site
to
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Figure 21-2. NEI Point Sources Located Within 10 Miles of CHSC
Legend
eo"2ffo-w eg115'crw s>' itrtrw srs'trw
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
CHSC NATTS site 10 mile radius [ | County boundary
Source Category Group (No. of Facilities)
f Aircraft Operations (1)
-$ Industrial Machinery and Equipment (1)
21-3
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Table 21-1. Geographical Information for the South Carolina Monitoring Site
Site
Code
CHSC
AQS Code
45-021-0001
Location
Not in a
city
County
Chesterfield
Micro- or
Metropolitan
Statistical Area
Not in an MSA
Latitude
and
Longitude
34.615367,
-80.198789
Land Use
Forest
Location
Setting
Rural
Additional Ambient Monitoring Information1
TSP, TSP Metals, VOCs, O3, Meteorological
parameters, PM10, PM10 Speciation, PM25, and
PM2 5 Speciation, Carbonyl Compounds,
Hexachlorobutadiene.
BOLD ITALICS = EPA-designated NATTS Site
to
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CHSC is located about 15 miles south of the North Carolina/South Carolina border,
between the towns of McBee and Chesterfield. The monitoring site is located near the Ruby fire
tower and, as Figure 21-1 shows, is located just off State Highway 145. The surrounding area is
rural in nature and is part of the Carolina Sandhills Wildlife Refuge. Figure 21-2 shows that few
point sources are located within 10 miles of CHSC, the closest of which is the Wild Irish Rose
Airport.
Table 21-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the South Carolina monitoring site. Table 21-2 includes county-level
population and vehicle registration information. Table 21-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of the site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding the monitoring site. Table 21-2 also
contains traffic volume information for CHSC. Finally, Table 21-2 presents the daily VMT for
Chesterfield County.
Table 21-2. Population, Motor Vehicle, and Traffic Information for the South Carolina
Monitoring Site
Site
CHSC
Estimated
County
Population1
46,557
County-level
Vehicle
Registration2
40,792
Vehicles per
Person
(Registration:
Population)
0.88
Population
within 10
miles3
5,538
Estimated
10-mile
Vehicle
Ownership
4,852
Annual
Average
Daily
Traffic4
550
County-
level Daily
VMT5
1,276,517
Bounty-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the South Carolina DMV (SC DMV, 2011)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the South Carolina DOT (SC DOT, 2012a)
5County-level VMT reflects 2011 data from the South Carolina DOT (SC DOT, 2012b)
BOLD ITALICS = EPA-designated NATTS Site
Observations from Table 21-2 include the following:
Chesterfield County's population is among the lowest compared to other counties
with NMP sites. This site's 10-mile population is the second lowest among NMP
sites, behind only CAMS 85 (in Texas). Similar rankings were found for both the
county-level and 10-mile vehicle ownerships.
The vehicle-per-person ratio is in the middle of the range among NMP sites.
21-5
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The traffic volume experienced near CHSC ranks among the lowest compared to
other NMP monitoring sites. The traffic estimate provided is for State Highway 145
between State Highway 109 and US-1.
The daily VMT for Chesterfield County is the third lowest VMT compared to other
counties with NMP sites (where VMT data were available).
21.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in South Carolina on sample days, as well as over the course of the year.
21.2.1 Climate Summary
The town of Chesterfield is located just south of the North Carolina/South Carolina
border, about 35 miles northwest of the city of Florence. Although the area experiences all four
seasons, South Carolina's southeastern location ensures mild winters and long, hot summers.
Summers are dominated by the Bermuda high pressure system over the Atlantic Ocean, which
allows southwesterly winds to prevail, bringing in warm, moist air out of the Gulf of Mexico.
During winter, winds out of the southwest shift northeasterly after frontal systems move across
the area. Chesterfield County leads the state in the average number of sleet and freezing rain
events per year (Bair, 1992 and SC SCO, 2013).
21.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station with adequate data is located at the Monroe
Airport in Monroe, North Carolina (WBAN 53872). Additional information about the Monroe
Airport weather station, such as the distance between the site and the weather station, is provided
in Table 21-3. These data were used to determine how meteorological conditions on sample days
vary from conditions experienced throughout the year.
21-6
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Table 21-3. Average Meteorological Conditions near the South Carolina Monitoring Site
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Chesterfield, South Carolina - CHSC
Monroe Airport
53872
(35.02, -80.62)
35.81
miles
311ฐ
(NW)
Sample
Day
2011
71.4
ฑ4.1
72.3
+ 1.6
61.4
ฑ3.9
61.7
+ 1.6
49.6
ฑ4.5
50.4
+ 1.7
55.3
ฑ3.7
55.6
+ 1.4
69.1
ฑ3.6
70.2
+ 1.3
1017.6
ฑ 1.6
1017.7
+ 0.7
4.8
ฑ0.6
4.8
+ 0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
to
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Table 21-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 21-3 is the 95 percent
confidence interval for each parameter. As shown in Table 21-3, average meteorological
conditions on sample days were representative of average weather conditions throughout the
year.
21.2.3 Back Trajectory Analysis
Figure 21-3 is the composite back trajectory map for days on which samples were
collected at the CHSC monitoring site in 2011. Included in Figure 21-3 are four back trajectories
per sample day. Figure 21-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 21-3 and 21-4 represents 100 miles.
Observations from Figures 21-3 and 21-4 for CHSC include the following:
Back trajectories originated from a variety of directions at CHSC.
The 24-hour air shed domain for CHSC was similar in size to other NMP monitoring
sites. The farthest away a back trajectory originated was over central Michigan, or
greater than 600 miles away. However, the average trajectory length was 206 miles
and 81 percent of back trajectories originated within 300 miles of the site.
The cluster analysis shows that 38 percent of back trajectories originated from the
southwest to west to northwest of CHSC, primarily over western North and South
Carolina and northern Georgia. Although most of these back trajectories originated
less than 300 miles away from the site, a few longer back trajectories originating to
the west of the site are also included. Eleven percent of back trajectories also
originated from the northwest of CHSC but of longer length (greater than 300 miles
away). Another 26 percent of back trajectories originated to the north to northeast of
CHSC, varying between 300 and 600 miles in length. Nearly 20 percent of back
trajectories are represented by the short cluster originating near the coast of South
Carolina. These back trajectories originated to the northeast, east, and southeast of
CHSC, over eastern North and South Carolina and their offshore waters. Fewer than
10 percent of back trajectories originated farther south, over the offshore waters of
Georgia and Florida.
21-8
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Figure 21-3. 2011 Composite Back Trajectory Map for CHSC
Figure 21-4. Back Trajectory Cluster Map for CHSC
21-9
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21.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Monroe Airport near CHSC
were uploaded into a wind rose software program to produce customized wind roses, as
described in Section 3.5.2.2. A wind rose shows the frequency of wind directions using "petals"
positioned around a 16-point compass, and uses different colors to represent wind speeds.
Figure 21-5 presents a map showing the distance between the NWS station and CHSC,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 21-5 also presents three different wind roses for the
CHSC monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
Observations from Figure 21-5 for CHSC include the following:
The Monroe Airport weather station is located across the North Carolina/South
Carolina border, approximately 36 miles northwest of CHSC.
The historical wind rose for CHSC shows that calm winds (< 2 knots) account for
23 percent of the hourly measurements. Winds from the south-southwest to west
account for approximately one-third of observations, just slightly more than winds
from the north to east-northeast. Winds from the southeast quadrant are generally not
observed.
The wind patterns shown on the 2011 wind rose for CHSC are similar to the historical
wind patterns, although there were slightly more calm observations and fewer winds
observations from the northeast quadrant. This indicates that wind conditions in 2011
were similar to what is expected climatologically near this site.
The sample day wind patterns for 2011 also resemble the historical and full-year wind
patterns. However, there were fewer observations from the southwest quadrant and
more observations from the northeast quadrant compared to the full-year wind rose.
21-10
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Figure 21-5. Wind Roses for the Monroe Airport Weather Station near CHSC
Distance between CHSC and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
21-11
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21.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the South Carolina monitoring
site in order to allow analysts and readers to focus on a subset of pollutants through the context
of risk. Each pollutant's preprocessed daily measurement was compared to its associated risk
screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by the monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 21-4 presents the results of the preliminary risk-based screening process for CHSC.
The pollutants that failed at least one screen and contributed to 95 percent of the total failed
screens for the monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. CHSC sampled hexavalent chromium and PAHs.
Table 21-4. Risk-Based Screening Results for the South Carolina Monitoring Site
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Chesterfield, South Carolina - CHSC
Naphthalene
0.029
Total
3
3
60
60
5.00
5.00
100.00
100.00
Observations from Table 21-4 include the following:
Naphthalene was the only pollutant to fail screens for CHSC. This pollutant was
detected in all 60 valid samples collected at CHSC and failed three screens, or
approximately 5 percent of screens.
This site has the third lowest number of failed screens (3) among all NMP sites.
Benzo(a)pyrene and hexavalent chromium were added to CHSC's pollutants of
interest because they are NATTS MQO Core Analytes, even though they did not fail
any screens. These pollutants are not shown in Table 21-4 but are shown in
subsequent tables in the sections that follow.
21-12
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21.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the South Carolina monitoring site. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest for CHSC, where the data meet the applicable criteria.
Concentration averages for select pollutants are also presented graphically for the site to
illustrate how the site's concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for CHSC are provided in Appendices M and O.
21.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for the South Carolina site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for CHSC are presented in
Table 21-5, where applicable. Note that if a pollutant was not detected in a given calendar
quarter, the quarterly average simply reflects "0" because only zeros substituted for non-detects
were factored into the quarterly average concentration.
21-13
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Table 21-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the South Carolina Monitoring Site
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Chesterfield, South Carolina - CHSC
Benzo(a)pyrene
Hexavalent Chromium
Naphthalene
7/60
29/60
60/60
0.02
ฑ0.03
<0.01
ฑ<0.01
25.11
ฑ 15.57
0
0.01
ฑ<0.01
12.38
ฑ2.45
0.03
ฑ0.05
0.01
ฑ<0.01
14.37
ฑ3.96
0.01
ฑ0.01
<0.01
ฑ<0.01
13.81
ฑ3.82
0.01
ฑ0.02
0.01
ฑ<0.01
16.42
ฑ4.13
Observations for CHSC from Table 21-5 include the following:
The annual average concentration of naphthalene is three orders of magnitude higher
than the annual average concentrations of hexavalent chromium and benzo(a)pyrene.
Compared to other NMP sites, CHSC has the second lowest annual average
concentration for each of these pollutants, second only to UNVT for each.
Benzo(a)pyrene was infrequently detected at CHSC. This pollutant was detected
twice in the first quarter, was not detected at all during the second quarter, was
detected once in the third quarter, and was detected three times in the fourth quarter
of 2011.
Although hexavalent chromium was detected in all four quarters of 2011, it was
detected in fewer than half of the samples collected (29 out of 60). The measurements
ranged from 0.0023 ng/m3 to 0.0244 ng/m3, with two-thirds of the concentrations
measured during the second (10) and third (10) quarters of 2011.
Naphthalene was detected in every sample collected at CHSC. The first quarter
average concentration is roughly twice the other quarterly averages and has a
relatively large confidence interval associated with it. The maximum naphthalene
concentration was measured on March 10, 2011 (122 ng/m3) and is more than twice
the next highest measurement (49.3 ng/m3), measured on the following sample day.
The concentrations measured at CHSC ranged from 4.54 ng/m3 to 122 ng/m3, with a
median concentration of 11.75 ng/m3.
21-14
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21.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzo(a)pyrene,
hexavalent chromium, and naphthalene were created for CHSC. Figures 21-6 through 21-8
overlay the site's minimum, annual average, and maximum concentrations onto the program-
level minimum, first quartile, median, average, third quartile, and maximum concentrations, as
described in Section 3.5.3.
Figure 21-6. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
Cr-SC
0.25
0.5
0.75 1 1.25
Concentration (ng/m3J
1.5
1.75
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 21-7. Program vs. Site-Specific Average Hexavalent Chromium Concentration
CHSC
0.05
3.1
5.15
Concentration (ng/mi)
DL25
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
21-15
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Figure 21-8. Program vs. Site-Specific Average Naphthalene Concentration
CHSC
Program Max Concentration =779 ng/m3
100
150
200 250 300
Concentration (ng/m3)
350
453
555
Program: IstQuartile 2ndQuartile 3rd Quartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 21-6 through 21-8 include the following:
Figure 21-6 is the box plot for benzo(a)pyrene. Note that the first quartile for this
pollutant is zero and is not visible on this box plot. This box plot shows that the
annual average concentration for CHSC is less than both the program-level
average and median concentrations. Figure 21-6 also shows that the maximum
concentration measured at CHSC is considerably less than the maximum
concentration measured across the program. Several non-detects of
benzo(a)pyrene were measured at CHSC.
Figure 21-7 is the box plot for hexavalent chromium and shows that the annual
average concentration of hexavalent chromium for CHSC is less than the
program-level first quartile (25th percentile). Further, the maximum concentration
measured at CHSC is just greater than the program-level average concentration.
More than half of the measurements of hexavalent chromium for CHSC were
non-detects.
Figure 21-8 is the box plot for naphthalene. Note that the program-level
maximum concentration (779 ng/m3) is not shown directly on the box plot
because the scale of the box plot would be too large to readily observe data points
at the lower end of the concentration range. Thus, the scale has been reduced to
500 ng/m3. Figure 21-8 shows that the annual naphthalene average for CHSC is
less than the program-level first quartile. The maximum naphthalene
concentration measured at CHSC is considerably less than the program-level
maximum concentration. There were no non-detects of naphthalene measured at
CHSC or across the program.
21-16
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21.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. CHSC has sampled hexavalent chromium under the NMP since 2005. Thus,
Figure 21-9 presents the annual statistical metrics for hexavalent chromium for CHSC. The
statistical metrics presented for assessing trends include the substitution of zeros for non-detects.
PAHs are excluded from this analysis because sampling for PAHs did not begin until 2008.
Figure 21-9. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at CHSC
(ration (ng/m3)
s c
Average Concen
T
1 ^
I* i
*
* - r
*-. i
* *
^ *
2005 2006 2007 200S 2009 2010 2011
Year
# 5th Pe re entile Minimum Median Maximum # 95th Percentile ..^.. Average
Observations from Figure 21-9 for hexavalent chromium measurements at CHSC include
the following:
Sampling for hexavalent chromium at CHSC began in January 2005.
The maximum concentration of hexavalent chromium was measured on
March 23, 2005 (0.147 ng/m3). The maximum concentration of hexavalent chromium
measured in subsequent time periods was considerably lower (by at least half). The
eight highest concentrations of hexavalent chromium were all measured in 2005 and
2006.
21-17
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The minimum, 5th percentile, and median concentrations are zero for each year
shown, indicating that at least 50 of the measurements collected at CHSC were non-
detects. The percentage of non-detects has varied from 52 percent (2011) to
91 percent (2009).
The maximum concentration, 95th percentile, and average concentration of hexavalent
chromium decreased significantly through 2007. Little change is shown in the
average concentration between 2007 and 2009. The range of concentrations measured
nearly tripled from 2009 to 2010; thus, the average concentration exhibits an increase
from 2009 to 2010, with little change in the average concentration from 2010 to 2011.
21.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
CHSC monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations regarding
the various toxicity factors, time frames, and calculations associated with these risk-based
screenings.
21.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
South Carolina monitoring site to the ATSDR MRLs, where available. As described in
Section 3.3, MRLs are noncancer health risk benchmarks and are defined for three exposure
periods: acute (exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and
chronic (exposures of 1 year or greater). The preprocessed daily measurements of the pollutants
of interest were compared to the acute MRLs; the quarterly averages were compared to the
intermediate MRLs; and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
21.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the South Carolina monitoring site and where annual
average concentrations could be calculated, risk was examined by calculating cancer risk and
noncancer hazard approximations. These approximations can be used as risk estimates for cancer
and noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
21-18
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confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 21-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
Table 21-6. Risk Approximations for the South Carolina Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Chesterfield, South Carolina - CHSC
Benzo(a)pyrene
Hexavalent Chromium
Naphthalene
0.00176
0.012
0.000034
0.0001
0.003
7/60
29/60
60/60
0.01
ฑ0.02
0.01
ฑ<0.01
16.42
ฑ4.13
0.03
0.08
0.56
<0.01
0.01
= a Cancer URE or Noncancer RfC is not available
Observations for CHSC from Table 21-6 include the following:
The cancer risk approximations for the pollutants of interest for CHSC are all less
than 1 in-a-million, with the highest cancer risk approximation calculated for
naphthalene (0.56 in-a-million).
The noncancer hazard approximations for the pollutants of interest are very low (0.01
or less), indicating that no adverse health effects are expected from these individual
pollutants. Because benzo(a)pyrene has no RfC, a noncancer hazard approximation
could not be calculated.
21.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 21-7 and 21-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 21-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from annual averages provided in
Table 21-6. Table 21-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from the annual averages
provided in Table 21-6.
21-19
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Table 21-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the South Carolina Monitoring Site
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Chesterfield, South Carolina (Chesterfield County) - CHSC
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Trichloroethylene
Dichloromethane
POM, Group 2b
Ethylene oxide
28.92
14.89
13.15
7.77
3.17
1.50
0.47
0.40
0.32
0.07
Benzene
Formaldehyde
1,3 -Butadiene
Hexavalent Chromium, PM
Naphthalene
Ethylbenzene
POM, Group 2b
POM, Group 3
POM, Group 5a
Acetaldehyde
2.26E-04
1.71E-04
9.52E-05
7.65E-05
5.11E-05
3.72E-05
2.81E-05
2.20E-05
1.92E-05
1.71E-05
Naphthalene
Hexavalent Chromium
Benzo(a)pyrene
0.56
0.08
0.03
to
o
-------
Table 21-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the South Carolina Monitoring Site
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Chesterfield, South Carolina (Chesterfield County) - CHSC
Toluene
Xylenes
Benzene
Methanol
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Methyl isobutyl ketone
Ethylene glycol
78.42
60.74
28.92
28.81
19.60
14.89
13.15
7.77
6.32
3.86
Acrolein
Cyanide Compounds, gas
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Xylenes
Naphthalene
Lead, PM
Manganese, PM
42,691.89
1,852.73
1,586.49
1,341.80
963.86
863.64
607.44
500.57
432.31
287.58
Naphthalene 0.01
Hexavalent Chromium O.01
to
to
-------
The pollutants listed in Tables 21-7 and 21-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on the site's annual averages
are limited to those pollutants for which the site sampled. As discussed in Section 21.3, CHSC
sampled for PAHs and hexavalent chromium only. In addition, the cancer risk and noncancer
hazard approximations are limited to those pollutants with enough data to meet the criteria for
annual averages to be calculated. A more in-depth discussion of this analysis is provided in
Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this analysis
may help policy-makers prioritize their air monitoring activities.
Observations from Table 21-7 include the following:
Benzene, ethylbenzene, and formaldehyde are the highest emitted pollutants with
cancer UREs in Chesterfield County.
Benzene, formaldehyde, and 1,3-butadiene are the pollutants with the highest
toxicity-weighted emissions (of the pollutants with cancer UREs) for Chesterfield
County.
Seven of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Chesterfield County.
Naphthalene appears on all three lists, with the sixth highest emissions, the fifth
highest toxicity-weighted emissions, and highest cancer risk approximation among
the pollutants of interest for CHSC.
Hexavalent chromium ranks fourth for its toxicity-weighted emissions, but is not
among the highest emitted pollutants.
Several POM Groups appear among the pollutants with the highest emissions and
toxicity-weighted emissions. POM, Group 2b includes several PAHs sampled for at
CHSC including acenaphthylene, fluoranthene, and perylene. POM, Group 5a
includes benzo(a)pyrene, which is one of CHSC's pollutants of interest. POM,
Group 5a ranks ninth for toxicity weighted emissions but is not among the highest
emitted. POM, Group 3 does not include any pollutants sampled for at CHSC.
Observations from Table 21-8 include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs in Chesterfield County.
21-22
-------
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, cyanide compounds (gaseous), and 1,3-butadiene.
Four of the highest emitted pollutants in Chesterfield County also have the highest
toxicity-weighted emissions.
Naphthalene does not appear among the highest emitted pollutants with a noncancer
toxicity factor, but ranks eighth among the pollutants with the highest toxicity-
weighted emissions. Hexavalent chromium does not appear on either emissions-based
list. These are the only two pollutants of interest with noncancer RfCs for CHSC.
21.6 Summary of the 2011 Monitoring Data for CHSC
Results from several of the data treatments described in this section include the
following:
ปซป Naphthalene was the only pollutant to fail screens for CHSC. This site has the third
lowest number of failed screens (3) among allNMP sites.
*ป* Of the site-specific pollutants of the interest, naphthalene had the highest annual
average concentration for CHSC; however, it was second lowest compared to other
NMP sites sampling naphthalene.
ปซป Concentrations ofhexavalent chromium increased from 2009 to 2010 and then held
steady for 2011.
21-23
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22.0 Sites in South Dakota
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the UATMP sites in South Dakota, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
22.1 Site Characterization
This section characterizes the monitoring sites by providing geographical and physical
information about the location of the sites and the surrounding areas. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
There are two South Dakota monitoring sites. One monitoring site is located in Sioux
Falls, South Dakota (SSSD) while the other is located in Union County (UCSD). Figures 22-1
and 22-3 are composite satellite images retrieved from ArcGIS Explorer showing the monitoring
sites in their urban and rural locations. Figures 22-2 and 22-4 identify nearby point source
emissions locations by source category, as reported in the 2008 NEI for point sources. Note that
only sources within 10 miles of the sites are included in the facility counts provided in
Figures 22-2 and 22-4. A 10-mile boundary was chosen to give the reader an indication of which
emissions sources and emissions source categories could potentially have a direct effect on the
air quality at the monitoring sites. Further, this boundary provides both the proximity of
emissions sources to the monitoring sites as well as the quantity of such sources within a given
distance of the sites. Sources outside each 10-mile radius are still visible on the maps, but have
been grayed out in order to show emissions sources just outside the boundaries. Table 22-1
provides supplemental geographical information such as land use, location setting, and locational
coordinates.
22-1
-------
Figure 22-1. Sioux Falls, South Dakota (SSSD) Monitoring Site
to
to
-------
Figure 22-2. NEI Point Sources Located Within 10 Miles of SSSD
Legend
&b SSSD UATMP site
5 45'CTVV 96'40'0-W 96'35'0"W 96'30'CTW
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
10 mile radius
County boundary
Source Category Group (No. of Facilities)
-f1 Aircraft Operations (7)
*ป Transportation Equipment (1)
22-3
-------
Figure 22-3. Union County, South Dakota (UCSD) Monitoring Site
to
to
-------
Figure 22-4. NEI Point Sources Located Within 10 Miles of UCSD
Legend
96-J5X1-W 96'4WW 96'35'0-W
Note: Due to facility density and collocation the total facilities
displayed may nol represent ali facilities within the area of interest.
UCSD UATM P site
10 mile radius
County boundary
Source Category Group (No. of Facilities)
-f1 Aircraft Operations (1)
22-5
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Table 22-1. Geographical Information for the South Dakota Monitoring Sites
Site
Code
SSSD
UCSD
AQS Code
46-099-0008
46-127-0001
Location
Sioux Falls
Not in a
City
County
Minnehaha
Union
Micro- or
Metropolitan
Statistical
Area
Sioux Falls, SD
MSA
Sioux City, IA-
NE-SD MSA
Latitude and
Longitude
43.54792,
-96.700769
42.751518,
-96.707208
Land Use
Commercial
Agricultural
Location
Setting
Urban/City
Center
Rural
Additional Ambient Monitoring Information1
SO2, NO, NO2, NOX, O3, Meteorological
parameters, PM10, PM2 5, and PM25 Speciation.
CO, SO2, NO, NO2, NOX, Meteorological
parameters, PM10, and PM25.
1 Data for additional pollutants are reported to AQS for SSSD and UCSD (EPA, 2012c); however, these data are not generated by ERG and are therefore not included
in this report.
to
to
-------
SSSD is located on the east side of Sioux Falls, in eastern South Dakota. The monitoring
site is located at the South Dakota School for the Deaf. The surrounding area is mixed usage,
with both commercial and residential areas surrounding the site. SSSD is less than 1/2 mile from
the intersection of Highway 42 (East 10th Street) and 1-229, as shown in Figure 22-1. As
Figure 22-2 shows, few emissions sources are located within 10 miles of SSSD. There are only
two source categories shown in Figure 22-2, the aircraft operations category, which includes
airports as well as small runways, heliports, or landing pads, and the transportation equipment
category. The emissions source closest to SSSD is a hospital heliport.
UCSD is located in Union County, the southeastern-most county of the state, where the
South Dakota state border follows the Missouri River and comes to a point near Sioux City, Iowa
at the Nebraska and Iowa borders. The UCSD monitoring site is located in a rural and
agricultural area in the town of Brule, north of Elk Point and west of Vermillion. As shown in
Figure 22-3, the monitoring site is located on a residential property surrounded by agricultural
fields. Interstate-29 runs northwest-southeast through the center of Union County and lies less
than 1.5 miles west of UCSD. Figure 22-4 shows that there is a single point source located
within 10 miles of the site. However, UCSD is south of a proposed power plant and oil refinery.
The purpose of monitoring at UCSD is to collect air quality data before, during, and after the
construction of the proposed power plant and oil refinery (SD DENR, 2011).
Table 22-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the South Dakota monitoring sites. Table 22-2 includes county-level
population and vehicle registration information. Table 22-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 22-2 also
contains traffic volume information for each site. Finally, Table 22-2 presents the county-level
daily VMT for Minnehaha and Union Counties.
22-7
-------
Table 22-2. Population, Motor Vehicle, and Traffic Information for the South Dakota
Monitoring Sites
Site
SSSD
UCSD
Estimated
County
Population1
171,752
14,651
County-level
Vehicle
Registration2
210,914
25,419
Vehicles per
Person
(Registration:
Population)
1.23
1.73
Population
within 10
miles3
186,954
5,577
Estimated
10-mile
Vehicle
Ownership
229,582
9,676
Annual
Average
Daily
Traffic4
18,700
156
County-
level Daily
VMT5
3,751,886
808,049
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the South Dakota Department of Revenue (SDDOR, 2012)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data for SSSD and 2007 data for UCSD from the South Dakota DOT (SD DOT, 2007 and
2011)
5County-level VMT reflects 2011 data from the South Dakota DOT (SD DOT, 2012)
Observations from Table 22-2 include the following:
Although SSSD's county-level population is an order of magnitude higher than the
county-level population for UCSD, both county-level populations are in the bottom
third compared to other counties with NMP sites, with UCSD ranking last. The
10-mile population for each site is also on the low side compared to other NMP sites,
particularly for UCSD.
SSSD's county-level vehicle registration is an order of magnitude higher than the
county-level vehicle registration for UCSD, but both of the county-level vehicle
registrations are on the low side compared to other counties with NMP sites. Union
County's vehicle registration is the lowest of all NMP counties, while Minnehaha
County is in the bottom third. The 10-mile vehicle ownership estimates for SSSD and
UCSD rank slightly higher among NMP sites than county-level vehicle ownerships.
The vehicle-per-person ratios for UCSD and SSSD are among the highest compared
to other NMP sites, ranking first and second, respectively. This indicates that
residents likely own multiple vehicles.
The traffic volume for SSSD is two orders of magnitude higher than the traffic
volume for UCSD. The traffic near UCSD is the second lowest among all NMP sites,
behind only BRCO. Traffic data for SSSD are provided for East 10th Avenue between
South Mable Avenue and South Highland Avenue; traffic data for UCSD are
provided for 475th Avenue near 317th Street.
The daily VMT for Minnehaha County is more than four times the VMT for Union
County. The daily VMT for Union County is the lowest among NMP sites (where
VMT was available). The VMT for Minnehaha County ranks tenth lowest among
counties with NMP sites (where VMT was available).
22-8
-------
22.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in South Dakota on sample days, as well as over the course of the year.
22.2.1 Climate Summary
The Sioux Falls area has a continental climate, with cold winters, warm summers, and
often drastic day-to-day variations. Precipitation varies throughout the year, with the spring and
summer seasons receiving more than half of the annual rainfall. On average, a south wind blows
in the summer and fall and a northwest wind blows in the winter and spring. Flooding is often a
concern in the area during springtime when snow begins to melt, although a flood control
system, including levees and a diversion channel, was constructed to reduce the flood threat
within the city limits and to divert water from the Big Sioux River and Skunk Creek around the
city (Bair, 1992).
Sioux City is located just north of the Missouri River where the Iowa border meets the
Nebraska and South Dakota borders. The climate near Sioux City is generally continental in
nature, with warm summers and cold, relatively dry winters. Precipitation is concentrated in the
spring and summer months. Wind direction varies with season, with southeasterly to southerly
winds in spring and summer, and northwesterly winds in fall and winter (Bair, 1992).
22.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather stations nearest these sites were
retrieved for 2011 (NCDC, 2011). The closest weather stations are located at Joe Foss Field
Airport (near SSSD) and Sioux Gateway Airport (near UCSD), WBAN 14944 and 14943,
respectively. Additional information about these weather stations, such as the distance between
the sites and the weather stations, is provided in Table 22-3. These data were used to determine
how meteorological conditions on sample days vary from conditions experienced throughout the
year.
22-9
-------
Table 22-3. Average Meteorological Conditions near the South Dakota Monitoring Sites
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Sioux Falls, South Dakota - SSSD
Joe Foss Field
Airport
14944
(43.58, -96.75)
3.20
miles
309ฐ
(NW)
Sample
Day
2011
56.3
ฑ5.9
55.9
+ 2.4
46.8
ฑ5.7
46.4
+ 2.3
37.0
ฑ5.5
36.1
+ 2.2
42.1
ฑ5.3
41.5
+ 2.1
71.8
ฑ3.0
70.4
+ 1.2
1014.3
ฑ2.1
1015.3
+ 0.8
8.6
ฑ1.0
8.2
+ 0.4
Union County, South Dakota - UCSD
Sioux
Gateway/Col.
Bud Day Field
Airport
14943
(42.39, -96.38)
29.45
miles
148ฐ
(SSE)
Sample
Day
2011
60.1
ฑ6.0
59.5
+ 2.4
49.0
ฑ5.7
48.7
+ 2.3
38.8
ฑ5.4
37.9
+ 2.2
43.9
ฑ5.2
43.4
+ 2.1
71.1
ฑ3.1
69.5
+ 1.2
1014.9
ฑ2.3
1015.4
+ 0.8
8.6
ฑ0.9
8.3
+ 0.4
to
to
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Table 22-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 22-3 is the 95 percent
confidence interval for each parameter. As shown in Table 22-3, average meteorological
conditions on sample days were representative of average weather conditions throughout the year
for both sites.
22.2.3 Back Trajectory Analysis
Figure 22-5 is the composite back trajectory map for days on which samples were
collected at the SSSD monitoring site in 2011. Included in Figure 22-5 are four back trajectories
per sample day. Figure 22-6 is the corresponding cluster analysis. Similarly, Figure 22-7 is the
composite back trajectory map for days on which samples were collected at UCSD and
Figure 22-8 is the corresponding cluster analysis. An in-depth description of these maps and how
they were generated is presented in Section 3.5.2.1. For the composite maps, each line represents
the 24-hour trajectory along which a parcel of air traveled toward the monitoring site on a given
sample day and time, based on an initial height of 50 meters AGL. For the cluster analyses, each
line corresponds to a trajectory representative of a given cluster of back trajectories. Each
concentric circle around the sites in Figures 22-5 through 22-8 represents 100 miles.
Observations from Figures 22-5 and 22-6 for SSSD include the following:
Back trajectories originated from a variety of directions at the SSSD site, but rarely
from due north.
The 24-hour air shed domain for SSSD is among the larger air sheds compared to the
other NMP monitoring sites. The farthest away a back trajectory originated was
southwest Montana, or greater than 700 miles away, although the average back
trajectory length was nearly 282 miles and 88 percent of back trajectories originated
within 450 miles of the site.
The cluster analysis shows that back trajectories originating from the southwest to
northwest of SSSD account for one-quarter of the back trajectories. Another one-
quarter of back trajectories originated to the northwest to north of SSSD, primarily
over North Dakota. The shorter cluster (34 percent) originating to the southeast of
SSSD represents shorter trajectories (< 300 miles) originating from a variety of
directions, although primarily over the state of Iowa. Eight percent of trajectories
originated from the south of SSSD over Kansas and Missouri and another eight
percent originated to the northeast of SSSD.
22-11
-------
Figure 22-5. 2011 Composite Back Trajectory Map for SSSD
Figure 22-6. Back Trajectory Cluster Map for SSSD
22-12
-------
Figure 22-7. 2011 Composite Back Trajectory Map for UCSD
Figure 22-8. Back Trajectory Cluster Map for UCSD
22-13
-------
Observations from Figures 22-7 and 22-8 for UCSD include the following:
Back trajectories originated from a variety of directions at the UCSD monitoring site,
with the longest back trajectories originating to the northwest of UCSD.
The 24-hour air shed domain for UCSD was larger in size compared to SSSD and
most other NMP sites. Two back trajectories originated farther than 900 miles away
(one over northwest Montana and one over northeast Oregon. The average back
trajectory length was greater than 300 miles; this is the only NMP site for which this
is true. However, 85 percent of the trajectories originated within 450 miles of the site.
The cluster analysis for UCSD shows that nearly 50 percent of back trajectories
originated to the west to northwest to north of the site, although these back
trajectories are represented by three cluster trajectories. One cluster trajectory
(12 percent) includes back trajectories originating to the west of UCSD over central
and western North and South Dakota and of relatively short length (<350 miles).
Another cluster trajectory (12 percent) includes back trajectories originating from the
northwest, primarily over Montana, and are relatively long (> 400 miles) in length.
The third cluster trajectory (25 percent) includes mostly shorter trajectories
originating to the northwest to north of UCSD and over North Dakota and northern
South Dakota. Roughly one-third of back trajectories (34 percent) originated to the
east and southeast over Iowa and Missouri. These were generally less than 300 miles
in length. Another 13 percent of back trajectories originated to the south of UCSD
and finally, three percent originated northeastward over Minnesota, Lake Superior,
and the Upper Peninsula of Michigan.
22.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations at Joe Foss Field (for SSSD)
and Sioux Gateway (for UCSD) Airports were uploaded into a wind rose software program to
produce customized wind roses, as described in Section 3.5.2.2. A wind rose shows the
frequency of wind directions using "petals" positioned around a 16-point compass, and uses
different colors to represent wind speeds.
Figure 22-9 presents a map showing the distance between the NWS station and SSSD,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 22-9 also presents three different wind roses for the
SSSD monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
22-14
-------
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically. Figure 22-10 presents the distance map and three wind roses
forUCSD.
Observations from Figure 22-9 for SSSD include the following:
The Joe Foss Field Airport weather station is located approximately 3.2 miles
northwest of SSSD.
The historical wind rose shows that winds from a variety of directions were observed
near SSSD, although winds from the south were observed the most (13 percent), and
southwesterly and west-southwesterly winds observed the least (less than 3 percent).
Calm winds were observed for approximately 11 percent of the observations. The
strongest winds tend to be from the south or the northwest quadrant.
The 2011 wind patterns are very similar to the historical wind patterns, indicating that
wind conditions in 2011 near SSSD are similar to historical wind conditions.
The sample day wind rose also resembles the historical and full-year wind roses, but
does exhibit some differences. The sample day wind rose has a higher percentage of
winds from the southeast quadrant and fewer from the northwest quadrant. In
addition, winds greater than 22 knots were observed with easterly winds as well as
winds from the southeast to south, and northwest to north-northwest.
Observations from Figure 22-10 for UCSD include the following:
The Sioux Gateway Airport weather station is located approximately 29 miles
south-southeast of UCSD, across the state border in Sioux City, Iowa. The weather
station is located less than a mile from the Missouri River.
The historical wind rose shows that winds from the southeast and northwest quadrants
were observed the most near UCSD. Calm winds were observed for less than eight
percent of the observations. The strongest winds tend to be from the south or the
northwest quadrant.
The 2011 wind patterns are similar to the historical wind patterns, although the calm
rate is slightly higher for 2011 (approximately 10 percent).
The sample day wind patterns resemble the historical and full-year wind patterns, but
have a higher percentage of east-southeasterly and southeasterly wind observations.
22-15
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Figure 22-9. Wind Roses for the Joe Foss Field Airport Weather Station near SSSD
Distance between SSSD and NWS Station
2001-2010 Historical Wind Rose
<-
' ..... ili< i/fe I
-
2011 Wind Rose
Sample Day Wind Rose
22-16
-------
Figure 22-10. Wind Roses for the Sioux Gateway Airport Weather Station near UCSD
Distance between UCSD and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
22-17
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22.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the South Dakota monitoring
sites in order to allow analysts and readers to focus on a subset of pollutants through the context
of risk. For each site, each pollutant's preprocessed daily measurement was compared to its
associated risk screening value. If the concentration was greater than the risk screening value,
then the concentration "failed the screen." Pollutants of interest are those for which the
individual pollutant's total failed screens contribute to the top 95 percent of the site's total failed
screens. In addition, if any of the NATTS MQO Core Analytes measured by each monitoring site
did not meet the pollutant of interest criteria based on the preliminary risk-based screening, that
pollutant was added to the list of site-specific pollutants of interest. A more in-depth description
of the risk-based screening process is presented in Section 3.2.
Table 22-4 presents the results of the preliminary risk-based screening process for the
South Dakota monitoring sites. The pollutants that failed at least one screen and contributed to
95 percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. SSSD and UCSD
sampled for VOCs, SNMOCs, and carbonyl compounds.
Table 22-4. Risk-Based Screening Results for the South Dakota Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Sioux Falls, South Dakota - SSSD
Benzene
Acetaldehyde
Formaldehyde
Carbon Tetrachloride
1,3-Butadiene
1 ,2-Dichloroethane
Acrylonitrile
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
1 , 1 ,2,2-Tetrachloroethane
Chloromethylbenzene
ฃ>-Dichlorobenzene
Dichloromethane
Propionaldehyde
0.13
0.45
0.077
0.17
0.03
0.038
0.015
0.4
0.045
0.017
0.02
0.091
7.7
0.8
Total
60
59
59
55
41
17
13
6
3
2
1
1
1
1
319
60
59
59
59
44
17
13
60
3
2
1
19
43
59
498
100.00
100.00
100.00
93.22
93.18
100.00
100.00
10.00
100.00
100.00
100.00
5.26
2.33
1.69
64.06
18.81
18.50
18.50
17.24
12.85
5.33
4.08
1.88
0.94
0.63
0.31
0.31
0.31
0.31
18.81
37.30
55.80
73.04
85.89
91.22
95.30
97.18
98.12
98.75
99.06
99.37
99.69
100.00
22-18
-------
Table 22-4. Risk-Based Screening Results for the South Dakota Monitoring Sites
(Continued)
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Union County, South Dakota - UCSD
Formaldehyde
Acetaldehyde
Benzene
Carbon Tetrachloride
Acrylonitrile
1 ,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
1,3-Butadiene
Ethylbenzene
1 ,2-Dibromoethane
1 , 1 ,2,2-Tetrachloroethane
Trichloroethylene
ฃ>-Dichlorobenzene
0.077
0.45
0.13
0.17
0.015
0.038
0.045
0.03
0.4
0.0017
0.017
0.2
0.091
Total
61
60
56
54
32
18
5
4
3
2
2
2
1
300
61
61
56
56
32
18
5
5
56
2
2
4
11
369
100.00
98.36
100.00
96.43
100.00
100.00
100.00
80.00
5.36
100.00
100.00
50.00
9.09
81.30
20.33
20.00
18.67
18.00
10.67
6.00
1.67
1.33
1.00
0.67
0.67
0.67
0.33
20.33
40.33
59.00
77.00
87.67
93.67
95.33
96.67
97.67
98.33
99.00
99.67
100.00
Observations from Table 22-4 include the following:
Fourteen pollutants failed at least one screen for SSSD; of these, five are NATTS
MQO Core Analytes. Thirteen pollutants failed screens for UCSD, of which six are
also NATTS MQO Core Analytes. Of the pollutants failing screens, the sites share
11 pollutants in common in Table 22-4.
For SSSD, seven pollutants (of which five are NATTS MQO Core Analytes) were
identified as pollutants of interest by the risk-based screening process. Chloroform,
tetrachloroethylene, trichloroethylene, and vinyl chloride were added to SSSD's
pollutants of interest because they are NATTS MQO Core Analytes, even though
they did not fail any screens. These pollutants are not shown in Table 22-4 but are
shown in subsequent tables in the sections that follow.
For UCSD, seven pollutants (of which four are NATTS MQO Core Analytes) were
identified as pollutants of interest by the risk-based screening process.
Trichloroethylene and 1,3-butadiene were added to the pollutants of interest for
UCSD because they are NATTS MQO Core Analytes, even though they did not
contribute to 95 percent of the total failed screens. Chloroform, tetrachloroethylene,
and vinyl chloride were added to UCSD's pollutants of interest because they are
NATTS MQO Core Analytes, even though they did not fail any screens. These three
pollutants are not shown in Table 22-4 but are shown in subsequent tables in the
sections that follow.
22-19
-------
Formaldehyde and benzene were detected in every valid sample collected at UCSD
and SSSD and failed 100 percent of screens. Other pollutants, such as acrylonitrile,
1,2-dichloroethane, and hexachloro-1,3-butadiene also failed 100 percent of screens
for each site but were detected less frequently.
Recall from Section 3.2 that if a pollutant was measured by both the TO-15 and
SNMOC methods at the same site, the TO-15 results were used for the risk-based
screening process. As the South Dakota sites sampled both VOCs (TO-15) and
SNMOCs, the TO-15 results were used for the 12 pollutants these methods have in
common.
22.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the South Dakota monitoring sites. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest for the South Dakota monitoring sites, where the data meet
the applicable criteria. Concentration averages for select pollutants are also presented graphically
for the sites to illustrate how the sites' concentrations compare to the program-level averages, as
presented in Section 4.1. In addition, concentration averages for select pollutants are presented
from previous years of sampling in order to characterize concentration trends at the sites.
Additional site-specific statistical summaries for SSSD and UCSD are provided in Appendices J
through L.
22.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each South Dakota site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the South Dakota
monitoring sites are presented in Table 22-5, where applicable. Note that if a pollutant was not
22-20
-------
detected in a given calendar quarter, the quarterly average simply reflects "0" because only zeros
substituted for non-detects were factored into the quarterly average concentration.
Table 22-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the South Dakota Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Hg/m3)
2nd
Quarter
Average
(Hg/m3)
3rd
Quarter
Average
(jig/m3)
4th
Quarter
Average
(jig/m3)
Annual
Average
(jig/m3)
Sioux Falls, South Dakota - SSSD
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
59/59
13/60
60/60
44/60
59/60
28/60
17/60
59/59
46/60
3/60
1/60
1.90
ฑ0.68
0.02
ฑ0.05
0.69
ฑ0.10
0.03
ฑ0.01
0.32
ฑ0.11
0.02
ฑ0.02
0.01
ฑ0.02
0.98
ฑ0.30
0.08
ฑ0.03
<0.01
ฑ0.01
0.01
ฑ0.01
1.31
ฑ0.23
0.06
ฑ0.04
0.60
ฑ0.12
0.03
ฑ0.02
0.65
ฑ0.05
0.04
ฑ0.03
0.02
ฑ0.02
2.53
ฑ0.71
0.09
ฑ0.03
0
0
1.56
ฑ0.36
0.05
ฑ0.04
0.56
ฑ0.09
0.04
ฑ0.02
0.64
ฑ0.04
0.04
ฑ0.03
0.01
ฑ0.01
2.50
ฑ0.38
0.06
ฑ0.03
0
0
1.51
ฑ0.23
0
0.67
ฑ0.13
0.07
ฑ0.02
0.57
ฑ0.07
0.07
ฑ0.02
0.06
ฑ0.02
2.05
ฑ0.45
0.09
ฑ0.03
O.01
ฑ0.01
0
1.57
ฑ0.21
0.03
ฑ0.02
0.63
ฑ0.05
0.04
ฑ0.01
0.54
ฑ0.05
0.04
ฑ0.01
0.02
ฑ0.01
2.01
ฑ0.28
0.08
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
Union County, South Dakota - UCSD
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Hexachloro- 1 ,3 -butadiene
61/61
32/56
56/56
5/56
56/56
14/56
18/56
61/61
5/56
1.26
ฑ0.24
0.25
ฑ0.03
0.50
ฑ0.06
0.01
ฑ0.01
0.47
ฑ0.08
0.03
ฑ0.02
0.01
ฑ0.02
0.97
ฑ0.19
0
1.30
ฑ0.25
0.34
ฑ0.03
0.39
ฑ0.06
0.01
ฑ0.01
0.59
ฑ0.09
0.01
ฑ0.01
0.02
ฑ0.02
1.66
ฑ0.42
0.02
ฑ0.03
2.71
ฑ0.87
NA
NA
NA
NA
NA
NA
1.72
ฑ0.34
NA
3.85
ฑ0.74
0
0.39
ฑ0.06
0.01
ฑ0.01
0.63
ฑ0.05
0.04
ฑ0.02
0.06
ฑ0.02
1.60
ฑ0.57
0.02
ฑ0.03
2.33
ฑ0.40
0.17
ฑ0.04
0.40
ฑ0.03
0.01
ฑ0.01
0.58
ฑ0.04
0.02
ฑ0.01
0.03
ฑ0.01
1.50
ฑ0.21
0.01
ฑ0.01
22-21
-------
Table 22-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the South Dakota Monitoring Sites (Continued)
Pollutant
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
#of
Measured
Detections
vs. # of
Samples
23/56
4/56
3/56
1st
Quarter
Average
(Ug/m3)
0.05
ฑ0.02
0.06
ฑ0.08
0.01
ฑ0.01
2nd
Quarter
Average
(Ug/m3)
0.03
ฑ0.02
0.01
ฑ0.02
0.01
ฑ0.01
3rd
Quarter
Average
(Ug/m3)
NA
NA
NA
4th
Quarter
Average
(Ug/m3)
0.03
ฑ0.02
0
0
Annual
Average
(Ug/m3)
0.03
ฑ0.01
0.02
ฑ0.02
0.01
ฑ0.01
Observations for SSSD from Table 22-5 include the following:
The pollutants with the highest annual average concentrations by mass are
formaldehyde (2.01 ฑ 0.28 |ig/m3) and acetaldehyde (1.57 ฑ 0.21 |ig/m3). These are
the only two pollutants of interest with an annual average greater than 1.0 |ig/m3.
The first quarter acetaldehyde average is higher than the other quarterly averages and
has a relatively large confidence interval associated with it. The maximum
acetaldehyde concentration was measured on March 10, 2011 (5.83 |ig/m3). This
concentration is one of only two acetaldehyde concentrations greater than 3 |ig/m3
measured at SSSD (the second was measured in September). Of the 10 acetaldehyde
concentrations greater than or equal to 2 |ig/m3 measured at SSSD, six were measured
during the first quarter of 2011.
Several of the VOC pollutants of interest have large confidence intervals relative to
their quarterly and annual averages. Most of these pollutants were detected in fewer
than half of the valid samples collected. For example, the confidence interval for the
first quarter average of acrylonitrile is greater than the average itself. This quarterly
average includes one measured detection of acrylonitrile (0.373 |ig/m3, measured on
March 22, 2011) and 14 non-detects. The other 12 measured detections of
acrylonitrile were from samples collected across the second and third quarters (there
were no measured detections of acrylonitrile in the fourth quarter of the year).
1,2-Dichloroethane is another example. This pollutant was detected 17 times in
samples collected in 2011. Two were measured during the first quarter, three in the
second, two in the third, and 10 in the fourth. These quarterly averages are a result of
many zeros substituted for non-detects combined with relatively low measurements.
For 1,2-dichloroethane, the concentrations ranged from 0.0446 |ig/m3 to 0.11 |ig/m3.
Observations for UCSD from Table 22-5 include the following:
The pollutants with the highest annual average concentrations by mass are
acetaldehyde (2.33 ฑ 0.40 |ig/m3) and formaldehyde (1.50 ฑ 0.21 |ig/m3). These are
the only two pollutants of interest with an annual average greater than 1.0 |ig/m3.
22-22
-------
For acetaldehyde, the third and fourth quarter averages are two and three times higher
than the first and second quarter averages. A review of the data shows that the
maximum concentration of acetaldehyde was measured on August 31, 2011
(6.93 |ig/m3). Two additional concentrations greater than 6 |ig/m3 were also measured
in October and November. All 16 concentrations greater than 3 |ig/m3 were measured
between August 31 and December 31, 2011. Conversely, all eight measurements less
than 1 |ig/m3 were measured between January and April. Formaldehyde does not
follow a similar trend.
Third quarter averages for the VOCs could not be calculated because sampler issues
resulted in several canister samples outside pressure limits.
With the exception of benzene, acrylonitrile, and carbon tetrachloride, many of the
VOCs were detected in fewer than half of the valid samples collected.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for SSSD and
UCSD from those tables include the following:
None of the annual average concentrations of the pollutants of interest for SSSD
appear in Tables 4-9 through 4-12.
UCSD has the second highest annual average concentration of acrylonitrile among
NMP sites sampling VOCs, as shown in Table 4-9. This site has the fourth highest
number of failed screens for this pollutant among all sites sampling VOCs.
UCSD also appears in Table 4-9 for hexachloro-l,3-butadiene, vinyl chloride,
trichloroethylene, and 1,2-dichloroethane. However, these pollutants were detected in
one-third or less of the valid samples collected.
The annual average concentration of acetaldehyde for UCSD ranks ninth among
NMP sites sampling carbonyl compounds. By comparison, the annual average
formaldehyde concentration for UCSD ranks 23rd compared to other NMP sites.
22.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde, benzene,
1,3-butadiene, and formaldehyde were created for both SSSD and UCSD. Figures 22-11 through
22-14 overlay the sites' minimum, annual average, and maximum concentrations onto the
program-level minimum, first quartile, median, average, third quartile, and maximum
concentrations, as described in Section 3.5.3.
22-23
-------
Figure 22-11. Program vs. Site-Specific Average Acetaldehyde Concentrations
UCSD
10
12
14
Concentration (^
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
16
Figure 22-12. Program vs. Site-Specific Average Benzene Concentrations
Program Max Concentration = 23.8 ug/m3
UCSD
1
Program Max Concentration = 23.8 ug/rn3
i
j
4 5
Concentration (|
10
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
22-24
-------
Figure 22-13. Program vs. Site-Specific Average 1,3-Butadiene Concentrations
Program Max Concentration = 9.51 ug/m3
UCSD
Program Max Concentration = 9.51 ug/m3
3.5
15
Concentration IVg,''m3)
2.5
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average
Site Minimum/Maximum
Figure 22-14. Program vs. Site-Specific Average Formaldehyde Concentrations
UCSD
10
15
Concentration (
25
30
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 22-11 through 22-14 include the following:
Figure 22-11 shows that the annual average acetaldehyde concentration for UCSD
is greater than the program-level average while the annual average for SSSD is
less than the program-level average and median concentrations. The range of
concentrations measured is larger at UCSD than at SSSD, although the maximum
concentration measured at both sites is less than the maximum concentration
measured across the program. There were no non-detects of acetaldehyde
measured at either site or across the program.
The program-level maximum benzene concentration (23.8 |ig/m3) is not shown
directly on the box plots in Figure 22-12 because the scale of the box plots would
be too large to readily observe data points at the lower end of the concentration
range. Thus, the scale has been reduced to 10 |ig/m3. This figure shows that the
22-25
-------
annual average benzene concentrations for both sites are less than the program-
level average and median concentrations of benzene. Further, the annual average
for UCSD is less than the program-level first quartile (25th percentile) and the
maximum benzene concentration measured at this site is just less than the
program-level median concentration. UCSD has the lowest annual average
benzene concentration among NMP sites sampling this pollutant. There were no
non-detects of benzene measured at either site or across the program.
Similar to the benzene graph, the program-level maximum 1,3-butadiene
concentration (9.51 |ig/m3) is not shown directly on the box plots in Figure 22-13
as the scale has been reduced to 3 |ig/m3 to allow for the observation of data
points at the lower end of the concentration range. This figure shows that the
annual average 1,3-butadiene concentrations for both sites are less than the
program-level average and median concentrations. The annual average for UCSD
is actually an order of magnitude less than the program-level median
concentration. Further, the maximum 1,3-butadiene measured at UCSD is also
less than the program-level median concentration. This site has lowest annual
average 1,3-butadiene concentration among NMP sites sampling this pollutant.
Figure 22-14 shows that although the annual average formaldehyde concentration
for SSSD is greater than the annual average for UCSD, the annual averages for
both sites are less than the program-level average and median concentrations. The
annual average for UCSD is equivalent to the program-level first quartile. The
maximum formaldehyde concentration measured at each site is considerably less
than the maximum concentration measured across the program. There were no
non-detects of formaldehyde measured at either site.
22.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. Sampling at SSSD began in 2008 after a re-location from a previous sampling site.
Sampling at UCSD under the NMP began in 2009 and was completed at the end of 2011. Thus, a
trends analysis was not performed for either site.
22.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
South Dakota monitoring sites. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
22-26
-------
22.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
South Dakota monitoring sites to the ATSDR MRLs, where available. As described in
Section 3.3, MRLs are noncancer health risk benchmarks and are defined for three exposure
periods: acute (exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and
chronic (exposures of 1 year or greater). The preprocessed daily measurements of the pollutants
of interest were compared to the acute MRLs; the quarterly averages were compared to the
intermediate MRLs; and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
22.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the South Dakota sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 22-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
22-27
-------
Table 22-6. Risk Approximations for the South Dakota Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Sioux Falls, South Dakota - SSSD
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0000078
0.00003
0.000006
0.000026
0.000013
0.00000026
0.0000048
0.0000088
0.009
0.002
0.03
0.002
0.1
0.098
2.4
0.0098
0.04
0.002
0.1
59/59
13/60
60/60
44/60
59/60
28/60
17/60
59/59
46/60
3/60
1/60
1.57
ฑ0.21
0.03
ฑ0.02
0.63
ฑ0.05
0.04
ฑ0.01
0.54
ฑ0.05
0.04
ฑ0.01
0.02
ฑ0.01
2.01
ฑ0.28
0.08
ฑ0.01
<0.01
ฑ<0.01
0.01
ฑ0.01
3.46
2.33
4.92
1.33
3.26
0.62
26.08
0.02
0.01
0.01
0.17
0.02
0.02
0.02
0.01
0.01
0.01
0.20
0.01
O.01
0.01
Union County, South Dakota - UCSD
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.000068
0.0000078
0.00003
0.000006
0.000026
0.000013
0.000022
0.00000026
0.0000048
0.0000088
0.009
0.002
0.03
0.002
0.1
0.098
2.4
0.0098
0.09
0.04
0.002
0.1
61/61
32/56
56/56
5/56
56/56
14/56
18/56
61/61
5/56
23/56
4/56
3/56
2.33
ฑ0.40
0.17
ฑ0.04
0.40
ฑ0.03
0.01
ฑ0.01
0.58
ฑ0.04
0.02
ฑ0.01
0.03
ฑ0.01
1.50
ฑ0.21
0.01
ฑ0.01
0.03
ฑ0.01
0.02
ฑ0.02
0.01
ฑ0.01
5.12
11.77
3.11
0.09
3.47
0.69
19.53
0.28
0.01
0.08
0.01
0.26
0.09
0.01
0.01
0.01
0.01
O.01
0.15
O.01
0.01
0.01
0.01
= a Cancer URE or Noncancer RfC is not available
22-28
-------
Observations from Table 22-6 for SSSD include the following:
The pollutants with the highest annual average concentrations for SSSD are
formaldehyde, acetaldehyde, and benzene.
Formaldehyde, benzene, and acetaldehyde have the highest cancer risk
approximations among this site's pollutants of interest, although formaldehyde's
cancer risk approximation is an order of magnitude higher than the cancer risk
approximations for the other pollutants.
None of the noncancer hazard approximations were greater than 1.0, indicating that
no adverse health effects are expected from these individual pollutants.
Observations from Table 22-6 for UCSD include the following:
The pollutants with the highest annual average concentrations for UCSD are
acetaldehyde, formaldehyde, and carbon tetrachloride.
Formaldehyde has the highest cancer risk approximation for UCSD, followed by
acrylonitrile. The cancer risk approximation for acrylonitrile (11.77 in-a-million) is
the second highest cancer risk approximation for this pollutant. Although acrylonitrile
has a much lower annual average concentration than formaldehyde, the cancer risk
approximations are both greater than 10 in-a-million, indicating the relative toxicity
of this pollutant.
None of the noncancer hazard approximations for the pollutants of interest for UCSD
were greater than 1.0, indicating that no adverse health effects are expected from
these individual pollutants.
22.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 22-7 and 22-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 22-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 22-6. Table 22-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazards approximations (HQ), also calculated from annual averages provided
in Table 22-6.
22-29
-------
Table 22-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer
UREs for the South Dakota Monitoring Sites
Top 10 Total Emissions for Pollutants
with Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Sioux Falls, South Dakota (Minnehaha County) - SSSD
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group 6
POM, Group la
84.66
56.95
54.47
36.84
12.38
6.21
1.65
1.34
0.12
0.12
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
POM, Group 3
Hexavalent Chromium, PM
Ethylbenzene
POM, Group 2b
Acetaldehyde
POM, Group 5a
7.40E-04
6.60E-04
3.72E-04
2.11E-04
1.94E-04
1.48E-04
1.36E-04
1.18E-04
8.10E-05
5.09E-05
Formaldehyde
Benzene
Acetaldehyde
Carbon Tetrachloride
Acrylonitrile
1,3 -Butadiene
1 ,2-Dichloroethane
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
26.08
4.92
3.46
3.26
2.33
1.33
0.62
0.02
0.01
<0.01
Union County, South Dakota (Union County) - UCSD
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
POM, Group 2b
Dichloromethane
POM, Group 6
POM, Group la
15.98
12.81
10.98
8.37
2.12
1.15
0.23
0.13
0.02
0.01
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
Ethylbenzene
POM, Group 2b
Acetaldehyde
POM, Group 3
Hexavalent Chromium, PM
Arsenic, PM
1.67E-04
1.25E-04
6.36E-05
3.90E-05
2.74E-05
2.04E-05
1.84E-05
1.71E-05
1.56E-05
1.05E-05
Formaldehyde
Acrylonitrile
Acetaldehyde
Carbon Tetrachloride
Benzene
1 ,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
1,3 -Butadiene
Trichloroethylene
Vinyl Chloride
19.53
11.77
5.12
3.47
3.11
0.69
0.28
0.09
0.08
0.01
to
to
-------
Table 22-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with
Noncancer RfCs for the South Dakota Monitoring Sites
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Sioux Falls, South Dakota (Minnehaha County) - SSSD
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Ethylbenzene
Hexane
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
247.74
232.25
104.42
84.66
56.95
54.47
49.47
36.84
13.66
12.38
Acrolein
1,3 -Butadiene
Formaldehyde
Acetaldehyde
Benzene
Xylenes
Naphthalene
Lead, PM
Arsenic, PM
Propionaldehyde
148,988.96
6,191.87
5,811.72
4,093.12
2,821.95
2,322.48
2,068.40
871.54
550.67
461.12
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Benzene
Acrylonitrile
Carbon Tetrachloride
Tetrachloroethylene
Trichloroethylene
Chloroform
1 ,2-Dichloroethane
0.20
0.17
0.02
0.02
0.02
0.01
0.01
0.01
0.01
0.01
Union County, South Dakota (Union County) - UCSD
Toluene
Xylenes
Benzene
Formaldehyde
Ethylbenzene
Hexane
Acetaldehyde
Methanol
1,3 -Butadiene
1,1,1 -Trichloroethane
49.76
48.01
15.98
12.81
10.98
8.85
8.37
8.23
2.12
1.31
Acrolein
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Cyanide Compounds, gas
Benzene
Xylenes
Naphthalene
Arsenic, PM
Propionaldehyde
33,649.12
1,307.04
1,060.53
930.04
603.39
532.80
480.09
382.14
162.43
119.46
Acetaldehyde
Formaldehyde
Acrylonitrile
Benzene
Trichloroethylene
Carbon Tetrachloride
1,3 -Butadiene
Tetrachloroethylene
Chloroform
Hexachloro- 1 , 3 -butadiene
0.26
0.15
0.09
0.01
0.01
0.01
0.01
0.01
0.01
0.01
to
to
-------
The pollutants listed in Tables 22-7 and 22-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 22.3, SSSD and UCSD sampled for VOCs, SNMOCs, and carbonyl compounds. In
addition, the cancer risk and noncancer hazard approximations are limited to those pollutants
with enough data to meet the criteria for annual averages to be calculated, as discussed in
previous sections. A more in-depth discussion of this analysis is provided in Section 3.5.5.3.
Similar to the cancer risk and noncancer hazard approximations, this analysis may help policy-
makers prioritize their air monitoring activities.
Observations from Table 22-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Minnehaha and Union Counties. The emissions are higher in
Minnehaha County than in Union County, although both counties have relatively low
emissions of these pollutants. Union County has the lowest emissions of these three
pollutants among all counties with NMP sites.
Formaldehyde, benzene, and 1,3-butaidene are the pollutants with the highest
toxicity-weighted emissions (of the pollutants with cancer UREs) for both counties.
Seven of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Minnehaha County. The same seven pollutants appear on both
emissions-based lists for Union County.
Formaldehyde is the pollutant with the highest cancer risk approximation for SSSD;
this pollutant also appears on both emissions-based lists. This is also true for
acetaldehyde, benzene, and 1,3-butadiene. Conversely, several pollutants, including
carbon tetrachloride and acrylonitrile, appear on neither emissions-based list but are
among the pollutants with the highest cancer risk approximations for SSSD.
Formaldehyde has the highest cancer risk approximation for UCSD and appears on
both emissions-based lists. Conversely, acrylonitrile, which has the second highest
cancer risk approximation for UCSD, appears on neither emissions-based list.
Observations from Table 22-8 include the following:
Toluene and xylenes are the highest emitted pollutants with noncancer RfCs in both
Minnehaha and Union Counties. The emissions of these pollutants were an order of
magnitude higher in Minnehaha County than in Union County.
22-32
-------
Acrolein is the pollutant with the highest toxi city-weighted emissions (of the
pollutants with noncancer RfCs) for both counties. Although acrolein was sampled
for at SSSD and UCSD, this pollutant was excluded from the pollutants of interest
designation, and thus subsequent risk-based screening evaluations, due to questions
about the consistency and reliability of the measurements, as discussed in Section 3.2.
Acrolein is not one of the highest emitted pollutants in Minnehaha or Union Counties.
Five of the highest emitted pollutants also have the highest toxi city-weighted
emissions for Minnehaha County. The same five pollutants appear on both emissions-
based lists for Union County.
Formaldehyde and acetaldehyde, which have the highest noncancer hazard
approximations for SSSD and UCSD, appear on both emissions-based lists. Benzene
and 1,3-butadiene also appear on all three lists for each South Dakota monitoring site
while acrylonitrile appears on neither emissions-based list.
22.6 Summary of the 2011 Monitoring Data for SSSD and UCSD
Results from several of the data treatments described in this section include the
following:
ปซป Fourteen pollutants failed at least one screen for SSSD and 13 pollutants failed at
least one screen for UCSD.
ปซป For both sites, formaldehyde and acetaldehyde are the only pollutants for which the
annual average concentrations were greater than 1 jug/m3.
*ป* UCSD has the second highest annual average concentration of acrylonitrile among
NMP sites sampling VOCs. Conversely, UCSD has the lowest annual average
concentrations of benzene and 1,3-butadiene among sites sampling these pollutants.
22-33
-------
23.0 Sites in Texas
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS sites in Texas, and integrates these concentrations with
emissions, meteorological, and risk information. Data generated by sources other than ERG are
not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
23.1 Site Characterization
This section characterizes the CAMS 35 and CAMS 85 monitoring sites by providing
geographical and physical information about the location of the sites and the surrounding areas.
This information is provided to give the reader insight regarding factors that may influence the
air quality near the sites and assist in the interpretation of the ambient monitoring measurements.
The CAMS 35 monitoring site is located in the Houston-Sugarland-Baytown, Texas
MSA and CAMS 85 is part of the Marshall, Texas MSA. Figures 23-1 and 23-3 are composite
satellite images retrieved from ArcGIS Explorer showing the monitoring sites in their urban and
rural locations. Figures 23-2 and 23-4 identify nearby point source emissions locations by source
category for each site, as reported in the 2008 NEI for point sources. Note that only sources
within 10 miles of the sites are included in the facility counts provided in Figures 23-2 and 23-4.
A 10-mile boundary was chosen to give the reader an indication of which emissions sources and
emissions source categories could potentially have a direct effect on the air quality at the
monitoring sites. Further, this boundary provides both the proximity of emissions sources to the
monitoring sites as well as the quantity of such sources within a given distance of the sites.
Sources outside the 10-mile radius are still visible on each map, but have been grayed out in
order to show emissions sources just outside the boundary. Table 23-1 provides supplemental
geographical information such as land use, location setting, and locational coordinates.
23-1
-------
Figure 23-1. Deer Park, Texas (CAMS 35) Monitoring Site
to
-------
Figure 23-2. NEI Point Sources Located Within 10 Miles of CAMS 35
Legend
ฉ CAMS 35 NATTS site
O'w 95"5'(rw 95- Q'trw
Note: Due to facility donsitv and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
10 mile radius
County boundaries
Source Category Group (No. of Facilities) ป
-f1 Aircraft Operations (24) ?
I Asphalt Processing/Roofing Manufacturing (1) M
B Bulk Terminals/Bulk Plants (6)
C Chemical Manufacturing (59) a
* Electricity Generation via Combustion (8) B
E Electroplating, Plating. Polishing, Anodizing, & Coloring (2) R
<> Fabricated Metal Products (8) ฑ
IV Glass Manufacturing (1)
v Heating Equipment Manufacturing (1) ซ&
Landfill (2) i
Marine Port (4)
Miscellaneous Commercial/Industrial (22)
Miscellaneous Manufacturing (2)
Oil and/or Gas Production (11)
Petroleum Refinery (5)
Pulp and Paper Plant/Wood Products (3)
Rubber and Miscellaneous Plastics Products (19)
Ship Building and Repairing (4)
Stationary Combustion Turbines (1)
Transportation and Marketing of Petroleum Products (6)
Wastewater Treatment (2)
23-3
-------
Figure 23-3. Karnack, Texas (CAMS 85) Monitoring Site
-------
Figure 23-4. NEI Point Sources Located Within 10 Miles of CAMS 85
Legend
94"15t>"W W10WV W5'B"W 94rO'0"W
Note: Due to facilny density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
CAMS 85 NATTS site Q 10 mile radius
County boundaries
Source Category Group (No. of Facilities)
-f Aircraft Operations (3)
Oil and/or Gas Production (2)
23-5
-------
Table 23-1. Geographical Information for the Texas Monitoring Sites
Site Code
CAMS 35
CAMS 85
AQS Code
48-201-1039
48-203-0002
Location
Deer Park
Karnack
County
Harris
Harrison
Micro- or
Metropolitan
Statistical Area
Houston-Sugar
Land-Baytown,
TXMSA
Marshall, TX
MSA
Latitude
and
Longitude
29.670046,
-95.128485
32.669004,
-94.167449
Land Use
Residential
Agricultural
Location
Setting
Suburban
Rural
Additional Ambient Monitoring Information1
Haze, CO, NOy, NO, NO2, NOX, PAMS, NMOCs,
VOCs, Carbonyl compounds, O3, Meteorological
parameters, PM10, PM Coarse, PM10 Speciation,
PM2 5, and PM2 5 Speciation, SO2, SVOCs.
SVOCs, NO2, NO, NOX, PAMS, NMOCs, Carbonyl
Compounds, VOCs, O3, Meteorological parameters,
PMio, PM10 Speciation, PM25, PM2 5 Speciation.
:Data for additional pollutants are reported to AQS for these sites (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this report.
BOLD ITALICS = EPA-designated NATTS Site
to
-------
The CAMS 35 monitoring site is located in Deer Park, southeast of Houston, in east
Texas. This site serves as the Houston NATTS Site. The site is located at Brown Memorial Park,
in a primarily residential area, as shown in Figure 23-1. Major thoroughfares are near the site,
including Beltway 8 (1.5 miles to the west) and Highway 225 (nearly 3 miles to the north).
Galveston Bay is located to the east and southeast of the site and the Houston Ship Channel,
which runs from the Bay westward towards downtown Houston, is located to the north on the
other side of Highway 225. The east side of Houston has significant industry, including several
oil refineries. As Figure 23-2 shows, the point source located closest to the CAMS 35 monitoring
site is a heliport at San Jacinto College in Pasadena. However, a large number of emissions
sources are located roughly along a line that runs east to west just north of the site (or along the
Houston Ship Channel). A second cluster of emissions sources is located to the southeast of the
monitoring site. The source category with the greatest number of sources (59) surrounding
CAMS 35 is chemical manufacturing. Other source categories with a number of sources around
CAMS 35 include aircraft operations, which include airports as well as small runways, heliports,
or landing pads; rubber and miscellaneous plastics products; and oil and gas production.
The CAMS 85 NATTS site is located in Karnack, in northeast Texas. The monitoring site
is about 10 miles northeast of Marshall, Texas and about 7 miles from the Texas-Louisiana
border. This site is located on the property of the Longhorn Army Ammunition Plant near the
intersection of FM Road 134 and Spur Road 449 (Taylor Avenue), as shown in Figure 23-3. The
surrounding area is rural and agricultural. As Figure 23-4 shows, there are few point sources
within 10 miles of CAMS 85 and these sources fall into two source categories: aircraft
operations and oil and gas production. The closest source to CAMS 85 is the Fly-N-Fish Lodge
Airport.
Table 23-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Texas monitoring sites. Table 23-2 includes county-level
population and vehicle registration information. Table 23-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 23-2 also
23-7
-------
contains traffic volume information for each site. Finally, Table 23-2 presents the county-level
daily VMT for Harris and Harrison Counties.
Table 23-2. Population, Motor Vehicle, and Traffic Information for the Texas
Monitoring Sites
Site
CAMS 35
CAMS 85
Estimated
County
Population1
4,180,894
66,296
County-level
Vehicle
Registration2
3,164,173
70,585
Vehicles per
Person
(Registration:
Population)
0.76
1.06
Population
within 10
miles3
698,184
2,264
Estimated
10-mile
Vehicle
Ownership
528,398
2,410
Annual
Average
Daily
Traffic4
31,043
1,250
County-level
Daily VMT5
56,650,489
2,578,700
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Texas Department of Motor Vehicles (TX DMV, 2012)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2010 data for CAMS 85 from the Texas DOT and 2004 data for CAMS 35 from Harris County Public
Infrastructure Department (TX DOT, 2011 and HCPID, 2012)
5County-level VMT reflects 2011 data from the Texas DOT (TX DOT, 2012)
BOLD ITALICS = EPA-designated NATTS Site
Observations from Table 23-2 include the following:
The population and vehicle ownership counts are significantly higher for CAMS 35
than CAMS 85. Compared to other counties with NMP monitoring sites, Harris
County is third highest for both county-level population and county-level vehicle
ownership. Conversely, Harrison County is among the lowest for both county-level
population and vehicle ownership.
The 10-mile populations for both CAMS 35 and CAMS 85 do not reflect the
magnitude of the county-level populations, indicating that these sites are not located
near the centers of highest population density. The 10-mile population for CAMS 35
is in the middle of the range compared to other NMP sites, while the 10-mile
population for CAMS 85 is the lowest among all NMP sites. The estimated 10-mile
vehicle ownerships for each site exhibit similar rankings.
The vehicle-per-person ratio for CAMS 85 is higher than for CAMS 35. Compared to
other sites, the ratio for CAMS 85 is in the top third while the ratio for CAMS 35 is in
the bottom third.
The traffic volume passing CAMS 35 is significantly higher than the traffic volume
passing CAMS 85. The traffic volume for CAMS 35 is in the middle of the range
compared to other NMP sites while the traffic volume near CAMS 85 is among the
lower traffic volumes for NMP sites. Traffic data for CAMS 35 are provided for
Spencer Highway between Red Bluff Road and Underwood Road; the traffic data for
CAMS 85 are provided for FM Road 134.
23-8
-------
23.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Texas on sample days, as well as over the course of the year.
23.2.1 Climate Summary
The eastern third of Texas is characterized by a subtropical humid climate, with the
climate becoming more continental in nature farther north and west. The proximity to the Gulf of
Mexico acts as a moderating influence as temperatures soar in the summer or dip in the winter.
Areas closer to the coast, such as Houston, remain slightly cooler in the summer than
neighboring areas to the north. The reverse is also true, as coastal areas are warmer in the winter
than areas farther inland, although East Texas winters are relatively mild. The onshore flow from
the Gulf of Mexico also allows humidity levels to remain high in East Texas, particularly near
the coast. The winds flow out of the Gulf of Mexico a majority of the year, with the winter
months being the exception, as frontal systems allow colder air to filter in from the north.
Abundant rainfall is also typical of the region, again due in part to the nearness to the Gulf of
Mexico. Severe weather is most common in spring, particularly in May, and tropical systems can
be a threat to the state during the summer and fall. Snowfall is rare in East Texas but ice storms
are more common in northeast Texas than in other parts of the state (Bair, 1992 and TAMU,
2013).
23.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather stations nearest these sites were
retrieved for 2011 (NCDC, 2011). The closest weather station to CAMS 35 is located at William
P. Hobby Airport, WBAN 12918; the closest weather station to CAMS 85 is located at
Shreveport Regional Airport, WBAN 13957. Additional information about the Hobby Airport
and Shreveport Regional Airport weather stations, such as the distance between the sites and the
weather stations, is provided in Table 23-3. These data were used to determine how
meteorological conditions on sample days vary from conditions experienced throughout the year.
23-9
-------
Table 23-3. Average Meteorological Conditions near the Texas Monitoring Sites
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
Average
Temperature
Average
Dew Point
Temperature
Average
Wet Bulb
Temperature
Average
Relative
Humidity
Average
Sea Level
Pressure
(mb)
Average
Scalar
Wind
Speed
(kt)
Deer Park, Texas - CAMS 35
William P.
Hobby Airport
12918
(29.65, -95.28)
8.85
miles
258ฐ
(WSW)
Sample
Day
2011
80.1
ฑ3.8
81.2
+ 1.5
70.6
ฑ3.6
71.7
+ 1.4
56.8
ฑ4.0
58.6
+ 1.5
62.7
ฑ3.4
64.0
+ 1.3
65.8
ฑ3.1
67.1
+ 1.3
1016.7
ฑ1.5
1016.3
+ 0.6
7.2
ฑ0.8
7.1
+ 0.3
Karnack, Texas - CAMS 85
Shreveport
Regional
Airport
13957
(32.45, -93.82)
24.46
miles
127ฐ
(SE)
Sample
Day
2011
77.9
ฑ4.8
79.4
+ 1.9
66.4
ฑ4.6
68.0
+ 1.8
51.0
ฑ4.0
52.7
+ 1.5
57.6
ฑ3.8
59.1
+ 1.4
62.5
ฑ3.4
62.6
+ 1.4
1016.2
ฑ 1.6
1015.7
+ 0.6
6.9
ฑ0.8
6.7
+ 0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
to
o
-------
Table 23-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 23-3 is the 95 percent
confidence interval for each parameter. Although the differences are not statistically significant,
the average temperature and moisture parameters for both sites are slightly higher for all of 2011
than they are for sample days alone.
23.2.3 Back Trajectory Analysis
Figure 23-5 is the composite back trajectory map for days on which samples were
collected at the CAMS 35 monitoring site in 2011. Included in Figure 23-5 are four back
trajectories per sample day. Figure 23-6 is the corresponding cluster analysis. Figure 23-7 is the
composite back trajectory map for days on which samples were collected at CAMS 85 and
Figure 23-8 is the corresponding cluster analysis. An in-depth description of these maps and how
they were generated is presented in Section 3.5.2.1. For the composite maps, each line represents
the 24-hour trajectory along which a parcel of air traveled toward the monitoring site on a given
sample day and time, based on an initial height of 50 meters AGL. For the cluster analyses, each
line corresponds to a trajectory representative of a given cluster of back trajectories. Each
concentric circle around the sites in Figures 23-5 through 23-8 represents 100 miles.
Observations from Figures 23-5 and 23-6 for CAMS 35 include the following:
Back trajectories originated from a variety of directions at the CAMS 35 monitoring
site, although the majority of trajectories originated over the Gulf of Mexico or to the
north of the site and rarely to the west of the site.
The 24-hour air shed domain for CAMS 35 is among the largest in size compared to
other NMP monitoring sites. The average trajectory length was 278 miles, which is
the fifth highest average trajectory length among NMP sites. Two back trajectories
originated greater than 800 miles away, over central Nebraska. Approximately
82 percent of back trajectories originated within 400 miles of the site.
The cluster analysis shows that greater than 50 percent of back trajectories originated
over the Gulf of Mexico, although the position over the Gulf and the trajectory length
varies. Another common trajectory origin is from the northwest to northeast
(25 percent). The short cluster trajectory originating near the Louisiana border
(21 percent) represents back trajectories originating primarily over east Texas and
Louisiana as well as relatively short trajectories originating from other directions and
generally within 300 miles of CAMS 35.
23-11
-------
Figure 23-5. 2011 Composite Back Trajectory Map for CAMS 35
Figure 23-6. Back Trajectory Cluster Map for CAMS 35
23-12
-------
Figure 23-7. 2011 Composite Back Trajectory Map for CAMS 85
Figure 23-8. Back Trajectory Cluster Map for CAMS 85
23-13
-------
Observations from Figures 23-7 and 23-8 for CAMS 85 include the following:
Back trajectories originated from a variety of directions at the CAMS 85 monitoring
site, although back trajectories originating to the east and west are rare. The
composite map for CAMS 85 resembles the composite map for CAMS 35 in the
direction of trajectory origin.
The 24-hour air shed domain for CAMS 85 is slightly smaller in size compared to
CAMS 35 but is similar in size to many other NMP monitoring sites. The farthest
away a trajectory originated was 800 miles away, near the Wyoming/Nebraska
border. However, the average trajectory length is 260 miles and most trajectories
(86 percent) originated less than 400 miles from CAMS 85.
The cluster analysis for CAMS 85 shows that that 44 percent of back trajectories
originated to the south of the site, as indicated by the short cluster (30 percent)
representing back trajectories originating over East Texas and the longer cluster
(14 percent) originating over the Gulf of Mexico. Another common trajectory origin
is from the southeast over Louisiana (24 percent). Additionally, 33 percent of back
trajectories originated to the northwest to northeast of the site, as indicated by the
short cluster (16 percent) representing relatively short back trajectories originating
over Arkansas and the longer cluster (17 percent) originating over the central Plains.
23.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations at Hobby Airport near
CAMS 35 and Shreveport Regional Airport near CAMS 85 were uploaded into a wind rose
software program to produce customized wind roses, as described in Section 3.5.2.2. A wind
rose shows the frequency of wind directions using "petals" positioned around a 16-point
compass, and uses different colors to represent wind speeds.
Figure 23-9 presents a map showing the distance between the NWS station and
CAMS 35, which may be useful for identifying topographical influences that may affect the
meteorological patterns experienced at this location. Figure 23-9 also presents three different
wind roses for the CAMS 35 monitoring site. First, a historical wind rose representing 2001 to
2010 wind data is presented, which shows the predominant surface wind speed and direction
over an extended period of time. Second, a wind rose representing wind observations for all of
2011 is presented. Next, a wind rose representing wind data for days on which samples were
collected in 2011 is presented. These can be used to identify the predominant wind speed and
direction for 2011 and determine if wind observations on sample days were representative of
conditions experienced over the entire year and historically. Figure 23-10 presents the distance
map and three wind roses for CAMS 85.
23-14
-------
Figure 23-9. Wind Roses for the William P. Hobby Airport Weather Station near CAMS 35
Distance between CAMS 35 and NWS Station
2001-2010 Historical Wind Rose
i \ C
2011 Wind Rose
Sample Day Wind Rose
23-15
-------
Figure 23-10. Wind Roses for the Shreveport Regional Airport Weather Station near
CAMS 85
Distance between CAMS 85 and NWS Station
2001-2010 Historical Wind Rose
IWEST
WIND SPEED
(Knots)
O *=
^| 17 21
^| 11 - 17
^| 7- 11
CH 4-7
! 2- 4
Calms: 18.58%
2011 Wind Rose
Sample Day Wind Rose
23-16
-------
Observations from Figure 23-9 for CAMS 35 include the following:
The Hobby Airport weather station is located approximately 8.9 miles west-southwest
of CAMS 35.
The historical wind rose shows that winds from the southeast quadrant, including
both easterly and southerly winds, prevailed near the CAMS 35 site. Northerly winds
were also observed often. Calm winds (<2 knots) were observed for approximately
14 percent of the wind measurements.
Winds from the southeast quadrant were frequently observed in 2011 as well, but the
number of south-southeasterly and southerly wind observations was higher in 2011
than historically. This is also true for the sample day wind rose.
Observations from Figure 23-10 for CAMS 85 include the following:
The Shreveport Regional Airport weather station is located across the Texas-
Louisiana border, approximately 24.5 miles southeast of CAMS 85.
The wind patterns on the historical wind rose for CAMS 85 resemble those on the
historical wind rose for CAMS 35. The historical wind rose shows that winds from
the southeast to south account for approximately 30 percent of the wind observations
near the CAMS 85. Northerly winds were also observed fairly often. Calm winds
were observed for approximately 17 percent of the wind measurements.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, although the number of southerly winds increased from roughly 13 percent
to 20 percent. A similar trend is shown for the CAMS 35 wind rose.
The sample day wind patterns resemble the full-year wind patterns, indicating that
wind conditions on sample days were representative of those experienced throughout
2011.
23.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Texas monitoring sites in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
For each site, each pollutant's preprocessed daily measurement was compared to its associated
risk screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by each monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
23-17
-------
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 23-4 presents the results of the preliminary risk-based screening process for
CAMS 35 and CAMS 85. The pollutants that failed at least one screen and contributed to
95 percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. CAMS 35 sampled
for hexavalent chromium and PAHs while CAMS 85 sampled for hexavalent chromium only.
Table 23-4. Risk-Based Screening Results for the Texas Monitoring Sites
Pollutant
Screening
Value
(Hg/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Deer Park, Texas - CAMS 35
Naphthalene
Fluorene
Acenaphthene
Hexavalent Chromium
Fluoranthene
0.029
0.011
0.011
0.000083
0.011
Total
53
7
6
6
o
J
75
58
58
58
60
58
292
91.38
12.07
10.34
10.00
5.17
25.68
70.67
9.33
8.00
8.00
4.00
70.67
80.00
88.00
96.00
100.00
Karnack, Texas - CAMS 85
Hexavalent Chromium
0.000083
Total
0
0
50
50
0.00
0.00
0.00
0.00
Observations from Table 23-4 include the following:
Five pollutants, including two NATTS MQO Core Analytes, failed at least one screen
for CAMS 35. Naphthalene contributed to 71 percent of the total number of failed
screens for CAMS 35.
Naphthalene, fluorene, acenaphthene, and hexavalent chromium were initially
identified as pollutants of interest for CAMS 35. Benzo(a)pyrene was added to the
pollutants of interest for CAMS 35 because it is a NATTS MQO Core Analyte, even
though it did not fail any screens. Benzo(a)pyrene is not shown in Table 23-4 but is
shown in subsequent tables in the sections that follow.
Hexavalent chromium is the only pollutant sampled for at CAMS 85. This pollutant
did not fail any screens during the 2011 monitoring effort. However, because it is a
NATTS MQO Core Analyte, and because it is the only pollutant sampled for at this
site, hexavalent chromium is the pollutant of interest for CAMS 85.
23-18
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23.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Texas monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Texas monitoring sites, where the data meet the applicable
criteria. Concentration averages for select pollutants are also presented graphically for the sites to
illustrate how the sites' concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the sites. Additional site-
specific statistical summaries for CAMS 35 and CAMS 85 are provided in Appendices M and O.
23.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Texas site, as described in Section 3.1. The quarterly average of a particular pollutant is
simply the average concentration of the preprocessed daily measurements over a given calendar
quarter. Quarterly average concentrations include the substitution of zeros for all non-detects. A
site must have a minimum of 75 percent valid samples of the total number of samples possible
within a given quarter for a quarterly average to be calculated. An annual average includes all
measured detections and substituted zeros for non-detects for the entire year of sampling. Annual
averages were calculated for pollutants where three valid quarterly averages could be calculated
and where method completeness was greater than or equal to 85 percent, as presented in
Section 2.4. Quarterly and annual average concentrations for the Texas monitoring sites are
presented in Table 23-5, where applicable. Note that if a pollutant was not detected in a given
calendar quarter, the quarterly average simply reflects "0" because only zeros substituted for
non-detects were factored into the quarterly average concentration.
23-19
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Table 23-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Texas Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Deer Park, Texas - CAMS 35
Acenaphthene
Benzo(a)pyrene
Fluorene
Hexavalent Chromium
Naphthalene
58/58
23/58
58/58
60/60
58/58
2.45
ฑ0.72
0.02
ฑ0.02
3.05
ฑ0.76
0.04
ฑ0.01
81.21
ฑ27.31
4.94
ฑ1.58
0.01
ฑ0.01
5.57
ฑ2.08
0.05
ฑ0.01
52.65
ฑ 18.88
14.08
ฑ7.24
0.02
ฑ0.01
17.00
ฑ9.06
0.06
ฑ0.01
113.19
ฑ35.95
3.76
ฑ0.77
0.04
ฑ0.02
4.42
ฑ0.83
0.04
ฑ0.01
126.77
ฑ 49.62
6.58
ฑ2.30
0.02
ฑ0.01
7.84
ฑ2.85
0.05
ฑ0.01
94.14
ฑ 18.02
Karnack, Texas - CAMS 85
Hexavalent Chromium
50/61
0.02
ฑ0.01
0.03
ฑ<0.01
0.02
ฑ0.01
0.01
ฑ0.01
0.02
ฑ<0.01
Observations from Table 23-5 include the following:
Naphthalene's annual average concentration is significantly higher than the annual
averages for the other pollutants of interest for CAMS 35.
Although naphthalene concentrations appear to be higher during the second half of
the year, the confidence intervals indicate that concentrations of this pollutant have a
considerable amount of variability associated with them. The maximum concentration
of naphthalene was measured at CAMS 35 on November 11, 2011 (299 ng/m3), and
additional concentrations greater than 200 ng/m3 were also measured in August (2),
November (1), and December (1). While concentrations greater than 100 ng/m3 were
measured in each quarter of 2011, most were measured during the second half of the
year (four in the first quarter, one in the second, seven in the third, and seven in the
fourth).
The third quarter average concentrations for acenaphthene and fluorene were
significantly higher than the other quarterly averages and have relatively large
confidence intervals associated with them. Concentrations of acenaphthene ranged
from 1.02 ng/m3 to 52.9 ng/m3, with the five highest concentrations all measured in
August. All 13 concentrations greater than 6 ng/m3 were measured between June and
September. Conversely, the nine concentrations of acenaphthene less than 2 ng/m3
were all measured in January, February, or December. A similar trend is exhibited by
fluorene.
Benzo(a)pyrene was detected in fewer than half of the valid PAH samples collected at
CAMS 35. Measured detections ranged from 0.0196 ng/m3 to 0.151 ng/m3, with only
one measurement greater than 0.1 ng/m3.
23-20
-------
Concentrations of hexavalent chromium were higher at CAMS 35 than at CAMS 85.
The hexavalent chromium concentrations ranged from 0.0019 ng/m3 to 0.159 ng/m3
at CAMS 35, with a total of three measurements greater than 0.1 ng/m3. Hexavalent
chromium concentrations ranged from a few non-detects to 0.0522 ng/m3 at
CAMS 85. Hexavalent chromium was detected in 100 percent of the valid samples
collected at CAMS 35, while the detection rate was lower at CAMS 85 (82 percent).
The annual average concentration of hexavalent chromium for CAMS 35 for 2011 is
similar to the annual average for 2010. This same is not true for CAMS 85. In 2010,
CAMS 85 had the highest annual average concentration of hexavalent chromium
(0.31 ฑ 0.16 ng/m3) among all NMP sites sampling this pollutant and was six times
higher than the annual average concentration for the Deer Park site. For 2011, the
annual average concentration of hexavalent chromium for CAMS 85 is an order of
magnitude lower (0.02 ฑ <0.01 ng/m3). This may be attributable to the use of stainless
steel filter holders used in the sampler which may have contaminated the samples.
Changing to a Teflonฎ filter holder has resulted in a decrease in hexavalent chromium
concentrations at CAMS 85. The filter holder was exchanged at the end of 2010.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for CAMS 35
and CAMS 85 from those tables include the following:
CAMS 35 appears in Table 4-11 three times. The annual average fluorene
concentration for CAMS 35 ranks fifth highest among sites sampling PAHs.
CAMS 35 also ranks sixth for acenaphthene and seventh for naphthalene.
As shown in Table 4-12, the annual average hexavalent chromium concentration for
CAMS 35 is the second highest annual average hexavalent chromium concentration
among NMP sites sampling this pollutant, behind only PXSS. The annual average
hexavalent chromium concentration for CAMS 85 ranks tenth highest among NMP
sites.
23.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzo(a)pyrene,
hexavalent chromium, and naphthalene were created for CAMS 35. A box plot for hexavalent
chromium was also created for CAMS 85. Figures 23-11 through 23-13 overlay the sites'
minimum, annual average, and maximum concentrations onto the program-level minimum, first
quartile, median, average, third quartile, and maximum concentrations, as described in
Section 3.5.3.
23-21
-------
Figure 23-11. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
CAMS 35
F
DL25
0.5
0.75 1 1.25
Concentration (ne/m3)
15
1.75
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 23-12. Program vs. Site-Specific Average Hexavalent Chromium Concentrations
1
CAMS 85
0.05
DL1
0.15
Concentration (ng/m3J
0.2
0.25
DL3
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 23-13. Program vs. Site-Specific Average Naphthalene Concentration
CAMS 35
H Program Max Concentration =779 ng/m3
100
is:
200 250 300
Concentration (ng/m3)
350
403
45;
5DD
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
23-22
-------
Observations from Figures 23-11 through 23-13 include the following:
Figure 23-11 is the box plot for benzo(a)pyrene for CAMS 35. Note that the first
quartile for this pollutant is zero and is not visible on this box plot. This box plot
shows that the annual average concentration for CAMS 35 is less than both the
program-level average and median concentrations. Figure 23-11 also shows that
the maximum concentration measured at CAMS 35 is considerably less than the
maximum concentration measured across the program. More than half of the
measurements of benzo(a)pyrene were non-detects at CAMS 35, as discussed in
the previous section.
Figure 23-12 for hexavalent chromium shows both sites, as both CAMS 35 and
CAMS 85 sampled this pollutant. The annual average concentration for CAMS 35
is greater than the program-level third quartile (75th percentile). The annual
average concentration for CAMS 85 is less than the program-level average but
greater than the program-level median concentration. The concentration range
measured at CAMS 35 is more than three times the concentration range for
CAMS 85, although the maximum concentration measured at both sites is less
than the maximum concentration measured across the program. There were no
non-detects of hexavalent chromium measured at CAMS 35 while 11 non-detects
were reported for CAMS 85.
Figure 23-13 is the box plot for naphthalene for CAMS 35. Note that the
program-level maximum concentration (779 ng/m3) is not shown directly on the
box plot because the scale of the box plot would be too large to readily observe
data points at the lower end of the concentration range. Thus, the scale has been
reduced to 500 ng/m3. Figure 23-13 shows that the annual average naphthalene
concentration for CAMS 35 is greater than the program-level average
concentration. The maximum naphthalene concentration measured at CAMS 35 is
significantly less than the program-level maximum concentration. There were no
non-detects of naphthalene measured at CAMS 35 or across the program.
23.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. CAMS 35 has not sampled PAHs continuously for 5 years as part of the NMP and
both sites began sampling hexavalent chromium under the NMP in 2010. Therefore, a trends
analysis was not conducted.
23-23
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23.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
Texas monitoring sites. Refer to Sections 3.3 and 3.5.5 for definitions and explanations regarding
the various toxicity factors, time frames, and calculations associated with these risk-based
screenings.
23.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Texas monitoring sites to the ATSDRMRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
23.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Texas monitoring sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 23-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
23-24
-------
Table 23-6. Risk Approximations for the Texas Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Deer Park, Texas - CAMS 35
Acenaphthene
Benzo(a)pyrene
Fluorene
Hexavalent Chromium
Naphthalene
0.000088
0.00176
0.000088
0.012
0.000034
0.0001
0.003
58/58
23/58
58/58
60/60
58/58
6.58
ฑ2.30
0.02
ฑ0.01
7.84
ฑ2.85
0.05
ฑ0.01
94.14
ฑ 18.02
0.58
0.04
0.69
0.59
3.20
0.01
0.03
Karnack, Texas - CAMS 85
Hexavalent Chromium
0.012
0.0001
50/61
0.02
ฑ0.01
0.26
0.01
= a Cancer URE or Noncancer RfC is not available
Observations from Table 23-6 include the following:
The cancer risk approximation for naphthalene for CAMS 35 is 3.20 in-a-million,
based on the annual average. This is the only cancer risk approximation greater than
1.0 in-a-million for CAMS 35.
The cancer risk approximation for hexavalent chromium for CAMS 85
(0.26 in-a-million) is half the cancer risk approximation for hexavalent chromium for
CAMS 35 (0.59 in-a-million), although both are less than 1 in-a-million.
The noncancer hazard approximations for CAMS 35 and CAMS 85, where they could
be calculated, are less than 1.0, indicating that no adverse health effects are expected
from these individual pollutants.
23.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 23-7 and 23-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 23-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 23-6. Table 23-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 23-6.
23-25
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Table 23-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Texas Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Cancer Risk
Approximation
Pollutant (in-a-million)
Deer Park, Texas (Harris County) - CAMS 35
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Methyl tert butyl ether
Naphthalene
Propylene oxide
Dichloromethane
Tetrachloroethylene
1,418.35
1,260.11
827.79
699.55
446.24
168.21
142.12
85.80
77.80
23.32
Formaldehyde
1,3 -Butadiene
Benzene
Hexavalent Chromium, PM
Naphthalene
Nickel, PM
Arsenic, PM
Ethylbenzene
Acetaldehyde
POM, Group 2b
1.64E-02
1.34E-02
1.11E-02
1.04E-02
4.83E-03
4.62E-03
2.26E-03
2.07E-03
1.54E-03
1.44E-03
Naphthalene 3.20
Fluorene 0.69
Hexavalent Chromium 0.59
Acenaphthene 0.58
Benzo(a)pyrene 0.04
Karnack, Texas (Harrison County) - CAMS 85
Formaldehyde
Benzene
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
Ethylene oxide
Dichloromethane
Chloromethylbenzene
Carbon tetrachloride
108.38
64.37
55.52
37.76
15.22
13.37
9.90
3.67
1.31
1.08
Hexavalent Chromium, PM
Formaldehyde
Ethylene oxide
Benzene
1,3 -Butadiene
Naphthalene
Nickel, PM
Arsenic, PM
Acetaldehyde
Ethylbenzene
6.35E-03
1.41E-03
8.72E-04
5.02E-04
4.57E-04
4.54E-04
3.29E-04
1.34E-04
1.22E-04
9.44E-05
Hexavalent Chromium 0.26
to
to
-------
Table 23-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Texas Monitoring Sites
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Deer Park, Texas (Harris County) - CAMS 35
Toluene
Xylenes
Methanol
Hexane
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Styrene
4,428.76
3,249.06
2,707.58
1,559.23
1,418.35
1,260.11
827.79
699.55
446.24
359.89
Acrolein
1,3 -Butadiene
Formaldehyde
Nickel, PM
Acetaldehyde
Titanium tetrachloride
Hexamethylene-l,6-diisocyanate, gas
Chlorine
Naphthalene
Benzene
4,253,301.87
223,117.95
128,583.14
106,919.25
77,728.16
77,037.49
62,970.00
57,589.67
47,373.42
47,278.41
Naphthalene 0.03
Hexavalent Chromium O.01
Karnack, Texas (Harrison County) - CAMS 85
Toluene
Xylenes
Formaldehyde
Benzene
Ethylene glycol
Acetaldehyde
Hexane
Methanol
Chloromethane
Ethylbenzene
155.11
142.12
108.38
64.37
63.56
55.52
53.09
48.73
40.86
37.76
Acrolein
Hexamethylene-l,6-diisocyanate, gas
Manganese, PM
Chlorine
Formaldehyde
Cyanide Compounds, PM
Nickel, PM
1,3 -Butadiene
Acetaldehyde
Hexavalent Chromium, PM
647,128.44
31,490.00
23,210.90
22,445.25
11,059.67
9,776.20
7,623.51
7,611.02
6,168.54
5,294.84
Hexavalent Chromium O.01
to
to
-------
The pollutants listed in Tables 23-7 and 23-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 23.3, both Texas monitoring sites sampled hexavalent chromium; CAMS 35 also
sampled for PAHs. In addition, the cancer risk and noncancer hazard approximations are limited
to those pollutants with enough data to meet the criteria for annual averages to be calculated. A
more in-depth discussion of this analysis is provided in Section 3.5.5.3. Similar to the cancer risk
and noncancer hazard approximations, this analysis may help policy-makers prioritize their air
monitoring activities.
Observations from Table 23-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Harris County. Formaldehyde, benzene, and acetaldehyde are the
highest emitted pollutants with cancer UREs in Harrison County. The magnitude of
the emissions is significantly higher in Harris County than Harrison County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
cancer UREs) for Harris County are formaldehyde, 1,3-butadiene, and benzene. The
pollutants with the highest toxicity-weighted emissions for Harrison County are
hexavalent chromium, formaldehyde, and ethylene oxide.
Six of the highest emitted pollutants in Harris County also have the highest toxicity-
weighted emissions while seven of the highest emitted pollutants in Harrison County
also have the highest toxicity-weighted emissions.
Naphthalene is the only pollutant of interest for CAMS 35 that appears on both
emissions-based lists for Harris County. Although hexavalent chromium, which has
the third highest cancer risk approximation for CAMS 35, ranks fourth for toxicity-
weighted emissions, this pollutant is not one of the highest emitted in Harris County.
POM, Group 2b ranks tenth for toxicity-weighted emissions in Harris County. POM,
Group 2b includes several PAHs sampled for at CAMS 35 including acenaphthene
and fluorene, both pollutants of interest for CAMS 35. Benzo(a)pyrene, another
pollutant of interest for CAMS 35, is part of POM, Group 5a, which does not appear
on either emissions-based list for Harris County.
Hexavalent chromium, the only pollutant of interest for CAMS 85, is the pollutant
with the highest toxicity-weighted emissions for Harrison County, but is not among
the 10 highest emitted (its emissions rank 13th).
23-28
-------
Observations from Table 23-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in Harris County. Toluene, xylenes, and formaldehyde are the highest emitted
pollutants in Harrison County. The magnitude of the emissions is significantly higher
in Harris County than Harrison County.
The pollutant with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) for both counties is acrolein.
Four of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Harris County while only two of the highest emitted pollutants also
have the highest toxicity-weighted emissions for Harrison County.
Hexamethylene-l,6-diisocyante gas appears among the pollutants with the highest
toxicity-weighted emissions for both sites. This pollutant only appears among the
pollutants with the highest toxicity-weighted emissions for one additional NMP site
(CELA).
Naphthalene ranks ninth for toxicity-weighted emissions in Harris County but is not
one of the highest emitted pollutants with a noncancer RfC. Hexavalent chromium
does not appear on either emissions-based list for Harris County. These are the only
two pollutants of interest for CAMS 35 with noncancer toxicity factors.
Hexavalent chromium ranks tenth for toxicity-weighted emissions in Harrison County
but is not one of the highest emitted (with a noncancer RfC).
23.6 Summary of the 2011 Monitoring Data for CAMS 35 and CAMS 85
Results from several of the data treatments described in this section include the
following:
ปซป Five pollutants failed at least one screen for CAMS 35, with naphthalene accounting
for 71 percent of the total failed screens. Hexavalent chromium, the only pollutant
sampled for at CAMS 85, did not fail any screens.
*ป* Of the site-specific pollutants of the interest, naphthalene had the highest annual
average concentration for CAMS 35.
ปซป Concentrations of acenaphthene andfluorene were highest during the summer
months at CAMS 35.
ปซป Concentrations ofhexavalent chromium measured at CAMS 85 decreased
significantly from 2010 to 2011. This is a result of replacing the stainless steel filter
holder in the sampler with a Teflonฎ filter holder.
23-29
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24.0 Site in Utah
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Utah, and integrates these concentrations with
emissions, meteorological, and risk information. Data generated by sources other than ERG are
not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
24.1 Site Characterization
This section characterizes the BTUT monitoring site by providing geographical and
physical information about the location of the site and the surrounding area. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
site and assist in the interpretation of the ambient monitoring measurements.
BTUT is located in Bountiful, in northern Utah. Figure 24-1 is a composite satellite
image retrieved from ArcGIS Explorer showing the monitoring site in its urban location.
Figure 24-2 identifies nearby point source emissions locations by source category, as reported in
the 2008 NEI for point sources. Note that only sources within 10 miles of the site are included in
the facility counts provided in Figure 24-2. A 10-mile boundary was chosen to give the reader an
indication of which emissions sources and emissions source categories could potentially have a
direct effect on the air quality at the monitoring site. Further, this boundary provides both the
proximity of emissions sources to the monitoring site as well as the quantity of such sources
within a given distance of the site. Sources outside the 10-mile radius are still visible on the map,
but have been grayed out in order to show emissions sources just outside the boundary.
Table 24-1 provides supplemental geographical information such as land use, location setting,
and locational coordinates.
24-1
-------
Figure 24-1. Bountiful, Utah (BTUT) Monitoring Site
Tl
to
-------
Figure 24-2. NEI Point Sources Located Within 10 Miles of BTUT
112'IQ'CrW 112'5'trW
trssxrw nt-so'trw nv^xrw
111 55'fJ-W lirSCNTW 111'45'CrW 111'40'Q"W
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
BTUT NATTS site O 10 mile radius | | County boundary
Source Category Group (No. of Facilities)
Air-conditioning/Refrigeration (1 )
-f Aircraft Operations (8)
* Electricity Generation via Combustion (2)
ฎ Institutional - school (1 )
? Miscellaneous Commercial/Industrial (2)
M Miscellaneous Manufacturing (1)
^ Petroleum Refinery (5)
24-3
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Table 24-1. Geographical Information for the Utah Monitoring Site
Site
Code
BTUT
AQS Code
49-011-0004
Location
Bountiful
County
Davis
Micro- or
Metropolitan
Statistical Area
Ogden-Clearfield,
UTMSA
Latitude
and
Longitude
40.902967,
-111.884467
Land Use
Residential
Location
Setting
Suburban
Additional Ambient Monitoring Information1
SO2, NO, NO2, NOX, PAMS, O3, Meteorological
parameters, PM10, PM2 5, and PM2 5 Speciation.
BOLD ITALICS = EPA-designated NATTS Site
to
-k
-------
Bountiful is north of Salt Lake City, and is situated in a valley between the Great Salt
Lake to the west and the Wasatch Mountains to the east. Figure 24-1 shows that BTUT is located
on the property of Viewmont High School, in a primarily residential area. The site is located
about one-third of a mile from 1-15, which runs north-south through most of the surrounding
urban area including Salt Lake City, Clearfield, and Ogden. Figure 24-2 shows that all of the
point sources near BTUT are located to the south of the site. The facilities surrounding BTUT
are involved in a variety of industries, although the source categories with the greatest number of
point sources surrounding BTUT are aircraft operations, which include airports as well as small
runways, heliports, or landing pads, and petroleum refineries. The source closest to BTUT
generates electricity via combustion.
Table 24-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Utah monitoring site. Table 24-2 includes county-level population
and vehicle registration information. Table 24-2 also includes a county-level vehicle registration-
to-population ratio, which was calculated to represent the number of vehicles per person within
the monitoring site's residing county. In addition, the population within 10 miles of the site is
presented, based on postal code population data estimates. An estimate of 10-mile vehicle
ownership was determined by applying the county-level vehicle registration-to-population ratio
to the 10-mile population surrounding the monitoring site. Table 24-2 also contains traffic
volume information for BTUT. Finally, Table 24-2 presents the county-level daily VMT for
Davis County.
Table 24-2. Population, Motor Vehicle, and Traffic Information for the Utah Monitoring
Site
Site
BTUT
Estimated
County
Population1
311,811
County-level
Vehicle
Registration2
239,582
Vehicles per
Person
(Registration:
Population)
0.77
Population
within 10
miles3
268,749
Estimated
10-mile
Vehicle
Ownership
206,495
Annual
Average
Daily
Traffic4
113,955
County-
level
Daily
VMT5
6,866,779
Bounty-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Utah Tax Commission (UT TC, 2011)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2010 data from the Utah DOT (UT DOT, 2010)
5County-level VMT reflects 2011 data from the Utah DOT (UT DOT, 2012)
BOLD ITALICS = EPA-designated NATTS Site
24-5
-------
Observations from Table 24-2 include the following:
Davis County's population is in the mid-to-low end of the range, as is its 10-mile
population, compared to counties with NMP sites. The county-level vehicle
registration and 10-mile ownership estimate rankings are similar to the population
rankings.
The vehicle-per-person ratio (0.78) is in the bottom third of the range compared to
other NMP sites.
The traffic volume experienced near BTUT is in the top third compared to other NMP
monitoring sites. The traffic estimate provided is for the intersection of 1-15 with
US-89, just west of the site.
The daily VMT for Davis County is on the mid-to-low end compared to counties with
NMP sites (where VMT was available).
24.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Utah on sample days, as well as over the course of the year.
24.2.1 Climate Summary
The Salt Lake City area's climate can be described as semi-arid and continental with
considerable seasonal variations. Summers are hot and dry while winters are cold and snow is
common. The area is generally dry, with spring as the wettest season, and sunshine prevails
across the area during much of the year. Precipitation that does fall can be enhanced over the
eastern parts of the valley as storm systems move up the side of the Wasatch Mountains, located
to the east. Surrounding mountains protect the valley from winter storm systems moving in from
the southwest or north, preventing cold air outbreaks. The Great Salt Lake tends to have a
moderating influence on the area's temperature. Moderate winds flow out of the southeast on
average, although there is a valley breeze/lake breeze system that affects the area. High pressure
systems that occasionally settle over the area can result in stagnation episodes (Bair, 1992 and
WRCC, 2013).
24-6
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24.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest BTUT were retrieved
for 2011 (NCDC, 2011). The closest weather station is located at Salt Lake City International
Airport (WBAN 24127). Additional information about the Salt Lake City International Airport
weather station, such as the distance between the site and the weather station, is provided in
Table 24-3. These data were used to determine how meteorological conditions on sample days
vary from conditions experienced throughout the year.
Table 24-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 24-3 is the 95 percent
confidence interval for each parameter. As shown in Table 24-3, average meteorological
conditions on sample days appear cooler than average weather conditions experienced
throughout the year, although the differences are not statistically significant. This is likely due to
a number of make-up samples collected in November and December of 2011.
24.2.3 Back Trajectory Analysis
Figure 24-3 is the composite back trajectory map for days on which samples were
collected at the BTUT monitoring site in 2011. Included in Figure 24-3 are four back trajectories
per sample day. Figure 24-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 24-3 and 24-4 represents 100 miles.
24-7
-------
to
J^.
oo
Table 24-3. Average Meteorological Conditions near the Utah Monitoring Site
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Bountiful, Utah - BTUT
Salt Lake City
International
24127
(40.79, -111.97)
8.98
miles
217ฐ
(SW)
Sample
Day
2011
58.8
ฑ5.1
61.4
+ 2.1
49.2
ฑ4.5
51.6
+ 1.9
31.7
ฑ2.9
33.2
+ 1.2
40.6
ฑ3.3
42.3
+ 1.4
57.2
ฑ4.3
55.5
+ 1.8
1016.1
ฑ2.1
1015.6
+ 0.9
6.6
ฑ0.8
6.7
+ 0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
-------
Figure 24-3. 2011 Composite Back Trajectory Map for BTUT
Figure 24-4. Back Trajectory Cluster Map for BTUT
24-9
-------
Observations from Figures 24-3 and 24-4 include the following:
Back trajectories originated from a variety of directions at BTUT. Back trajectories
originating from a direction with a westerly component tended to be longer than those
originating from a direction with an easterly component.
Similar to other sites located in the inter-mountain west, the 24-hour air shed domain
for BTUT is smaller in size than many other NMP monitoring sites. The farthest
away a back trajectory originated was over the Mojave Desert, or just less than
500 miles away. However, the average trajectory length was 176 miles and nearly
87 percent of back trajectories originated within 300 miles of the site.
The cluster analysis shows that nearly one-third of back trajectories are represented
by the short cluster trajectory originating just southwest of the site. This cluster
represents back trajectories originating within roughly 150 miles of BTUT and over
the northern half of Utah. Thirty percent of back trajectories originated to the south of
BTUT, although of varying distances, as indicated by the shorter cluster trajectory
(23 percent), which represents back trajectories originating over the southern half of
Utah, and the longer cluster trajectory (7 percent), which represents longer back
trajectories originating primarily over northern Arizona. Back trajectories also
originated to the west, northwest, and north of BTUT, and are also represented by two
cluster trajectories; one representing shorter back trajectories originating primarily
over southern Idaho, and one representing longer back trajectories originating to the
west and northwest of BTUT over northeast Nevada and southwest Idaho.
24.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Salt Lake City International
Airport near BTUT were uploaded into a wind rose software program to produce customized
wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions
using "petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 24-5 presents a map showing the distance between the NWS station and BTUT,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 24-5 also presents three different wind roses for the
BTUT monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
24-10
-------
to determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
Observations from Figure 24-5 for BTUT include the following:
The Salt Lake City International Airport weather station is located approximately
9 miles southwest of BTUT.
The historical wind rose shows that southeasterly, south-southeasterly, and southerly
winds were prevalent near BTUT, accounting for approximately 40 percent of the
wind observations. Winds from the north-northwest and north were also common.
Calm winds (<2 knots) were observed for approximately 11 percent of the hourly
measurements from 2001-2010. The strongest wind speeds were observed with south-
southeasterly and southerly winds.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, indicating that wind conditions in 2011 were similar to wind conditions
experienced historically near BTUT.
The wind patterns shown on the sample day wind rose resemble the 2011 wind
patterns, indicating that conditions on sample days were representative of those
experienced over the entire year (and historically).
jjcuutina, inui^aung uiiau ^uiiuiuuna un aaiiipic uay
experienced over the entire year (and historically)
24.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the BTUT monitoring site in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
Each pollutant's preprocessed daily measurement was compared to its associated risk screening
value. If the concentration was greater than the risk screening value, then the concentration
"failed the screen." Pollutants of interest are those for which the individual pollutant's total
failed screens contribute to the top 95 percent of the site's total failed screens. In addition, if any
of the NATTS MQO Core Analytes measured by the BTUT monitoring site did not meet the
pollutant of interest criteria based on the preliminary risk-based screening, that pollutant was
added to the list of site-specific pollutants of interest. A more in-depth description of the risk-
based screening process is presented in Section 3.2.
24-11
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Figure 24-5. Wind Roses for the Salt Lake City International Airport Weather Station near
BTUT
Distance between BTUT and NWS Station
2001-2010 Historical Wind Rose
rj
Stall
i :
2011 Wind Rose
Sample Day Wind Rose
24-12
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Table 24-4 presents the results of the preliminary risk-based screening process for BTUT.
The pollutants that failed at least one screen and contributed to 95 percent of the total failed
screens for the monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. BTUT sampled for VOCs, carbonyl compounds,
SNMOCs, PAHs, metals (PMio), and hexavalent chromium and is one of only two sites sampling
the entire suite of pollutants under the NMP (NBIL is the other).
Table 24-4. Risk-Based Screening Results for the Utah Monitoring Site
Pollutant
Screening
Value
(Hg/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Bountiful, Utah - BTUT
Acet aldehyde
Benzene
Carbon Tetrachloride
Formaldehyde
1,3-Butadiene
Arsenic (PM10)
Manganese (PM10)
Naphthalene
Ethylbenzene
1 ,2-Dichloroethane
Nickel (PM10)
Dichloromethane
Acrylonitrile
/>-Dichlorobenzene
Hexachloro- 1 , 3 -butadiene
Propionaldehyde
Cadmium (PM10)
1 , 1 ,2,2-Tetrachloroethane
Hexavalent Chromium
Lead (PM10)
Xylenes
0.45
0.13
0.17
0.077
0.03
0.00023
0.005
0.029
0.4
0.038
0.0021
7.7
0.015
0.091
0.045
0.8
0.00056
0.017
0.000083
0.015
10
Total
60
60
60
60
48
43
38
38
25
15
14
13
7
6
6
6
4
4
1
1
1
510
60
60
60
60
49
58
60
62
60
15
60
60
7
29
6
60
60
4
53
60
60
1,003
100.00
100.00
100.00
100.00
97.96
74.14
63.33
61.29
41.67
100.00
23.33
21.67
100.00
20.69
100.00
10.00
6.67
100.00
1.89
1.67
1.67
50.85
11.76
11.76
11.76
11.76
9.41
8.43
7.45
7.45
4.90
2.94
2.75
2.55
1.37
1.18
1.18
1.18
0.78
0.78
0.20
0.20
0.20
11.76
23.53
35.29
47.06
56.47
64.90
72.35
79.80
84.71
87.65
90.39
92.94
94.31
95.49
96.67
97.84
98.63
99.41
99.61
99.80
100.00
Observations from Table 24-4 include the following:
Twenty-one pollutants, of which 12 are NATTS MQO Core Analytes, failed at least
one screen for BTUT.
The risk-based screening process identified 16 pollutants of interest for BTUT, of
which nine are NATTS MQO Core Analytes. Three pollutants (cadmium, hexavalent
chromium, and lead) were added to BTUT's pollutants of interest because they are
24-13
-------
NATTS MQO Core Analytes, even though they did not contribute to 95 percent of
the total failed screens. Six additional pollutants were added to BTUT's pollutants of
interest because they are also NATTS MQO Core Analytes, even though they did not
fail any screens: beryllium, benzo(a)pyrene, chloroform, tetrachloroethylene,
trichloroethylene, and vinyl chloride. These six pollutants are not shown in
Table 24-4 but are shown in subsequent tables in the sections that follow.
Nearly 50 percent of measured detections failed screens (of the pollutants that failed
at least one screen) for BTUT.
Acetaldehyde, benzene, carbon tetrachloride, and formaldehyde were detected in
every valid carbonyl compound and VOC sample collected at BTUT and failed
100 percent of screens. Other pollutants also failed 100 percent of screens but were
detected much less frequently.
Recall from Section 3.2 that if a pollutant was measured by both the TO-15 and
SNMOC methods at the same site, the TO-15 results were used for the risk-based
screening process. As BTUT sampled both VOCs (TO-15) and SNMOCs, the TO-15
results were used for the 12 pollutants these methods have in common.
24.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Utah monitoring site. Where applicable, the following calculations and data analyses were
performed: Time period-based concentration averages (quarterly and annual) are provided for the
pollutants of interest for BTUT, where the data meet the applicable criteria. Concentration
averages for select pollutants are also presented graphically for this site to illustrate how the
site's concentrations compare to the program-level averages, as presented in Section 4.1. In
addition, concentration averages for select pollutants are presented from previous years of
sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for BTUT are provided in Appendix J through Appendix O.
24.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for BTUT, as described in Section 3.1. The quarterly average of a particular pollutant is simply
the average concentration of the preprocessed daily measurements over a given calendar quarter.
Quarterly average concentrations include the substitution of zeros for all non-detects. A site must
have a minimum of 75 percent valid samples of the total number of samples possible within a
given quarter for a quarterly average to be calculated. An annual average includes all measured
detections and substituted zeros for non-detects for the entire year of sampling. Annual averages
24-14
-------
were calculated for pollutants where three valid quarterly averages could be calculated and
where method completeness was greater than or equal to 85 percent, as presented in Section 2.4.
Quarterly and annual average concentrations for the Utah monitoring site are presented in
Table 24-5, where applicable. Note that concentrations of the PAHs, metals, and hexavalent
chromium are presented in ng/m3 for ease of viewing. Also note that if a pollutant was not
detected in a given calendar quarter, the quarterly average simply reflects "0" because only zeros
substituted for non-detects were factored into the quarterly average concentration.
Table 24-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Utah Monitoring Site
Pollutant
# of Measured
Detections vs.
# of Samples
1st
Quarter
Average
(Hg/m3)
2nd
Quarter
Average
(jig/m3)
3rd
Quarter
Average
(jig/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(jig/m3)
Bountiful, Utah - BTUT
Acetaldehyde
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Dichloromethane
Ethylbenzene
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Propionaldehyde
Tetrachloroethylene
Trichloroethylene
60/60
7/60
60/60
49/60
60/60
29/60
29/60
15/60
60/60
60/60
60/60
6/60
60/60
41/60
11/60
3.30
ฑ 1.06
NA
NA
NA
NA
NA
NA
NA
NA
NA
8.37
ฑ3.63
NA
0.67
ฑ0.20
NA
NA
1.33
ฑ0.28
0.03
ฑ0.04
0.79
ฑ0.14
0.04
ฑ0.03
0.60
ฑ0.06
0.03
ฑ0.03
0.01
ฑ0.02
0.02
ฑ0.02
6.18
ฑ3.94
0.27
ฑ0.05
3.01
ฑ1.10
0.02
ฑ0.03
0.32
ฑ0.06
0.05
ฑ0.03
0
2.12
ฑ0.50
0.02
ฑ0.03
1.03
ฑ0.22
0.05
ฑ0.02
0.64
ฑ0.07
0.03
ฑ0.03
0.02
ฑ0.03
0.01
ฑ0.02
96.53
ฑ 117.86
0.37
ฑ0.05
4.42
ฑ1.56
0
0.47
ฑ0.09
0.06
ฑ0.03
0
1.94
ฑ0.43
0
1.44
ฑ0.30
0.17
ฑ0.04
0.64
ฑ0.07
0.10
ฑ0.02
0.05
ฑ0.01
0.05
ฑ0.02
1.92
ฑ1.84
0.55
ฑ0.11
2.13
ฑ0.23
0.01
ฑ0.01
0.36
ฑ0.08
0.14
ฑ0.04
0.04
ฑ0.02
2.19
ฑ0.35
0.02
ฑ0.01
1.14
ฑ0.15
0.10
ฑ0.02
0.61
ฑ0.03
0.06
ฑ0.02
0.05
ฑ0.02
0.03
ฑ0.01
53.90
ฑ 50.64
0.47
ฑ0.13
4.49
ฑ1.15
0.01
ฑ0.01
0.46
ฑ0.07
0.10
ฑ0.02
0.02
ฑ0.01
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of viewing.
NA = Not available due to the criteria for calculating a quarterly and/or annual average
24-15
-------
Table 24-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Utah Monitoring Site (Continued)
Pollutant
Vinyl Chloride
Arsenic (PM10)a
Benzo(a)pyrene a
Bery Ilium (PM10)a
Cadmium (PM10)a
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
# of Measured
Detections vs.
# of Samples
1/60
58/60
20/62
53/60
60/60
53/61
60/60
60/60
62/62
60/60
1st
Quarter
Average
(Hg/m3)
NA
0.71
ฑ0.62
0.06
ฑ0.06
0.01
ฑ0.01
0.15
ฑ0.13
0.02
ฑ0.01
4.14
ฑ3.27
4.76
ฑ1.88
54.33
ฑ21.23
1.98
ฑ0.81
2nd
Quarter
Average
(jig/m3)
0
0.36
ฑ0.20
0
0.01
ฑ0.01
0.07
ฑ0.03
0.02
ฑ0.01
2.26
ฑ 1.25
6.39
ฑ3.04
25.28
ฑ5.96
0.98
ฑ0.23
3rd
Quarter
Average
(jig/m3)
0
0.43
ฑ0.09
0.02
ฑ0.01
0.02
ฑ0.01
0.09
ฑ0.02
0.02
ฑ0.02
2.62
ฑ0.58
10.17
ฑ1.90
46.19
ฑ9.36
1.80
ฑ0.74
4th
Quarter
Average
(Ug/m3)
0
0.87
ฑ0.50
0.10
ฑ0.05
0.01
ฑ0.01
0.27
ฑ0.15
0.02
ฑ0.01
5.15
ฑ2.16
8.64
ฑ2.80
62.83
ฑ18.12
2.19
ฑ0.83
Annual
Average
(jig/m3)
O.01
ฑ<0.01
0.59
ฑ0.19
0.04
ฑ0.02
0.01
ฑ0.01
0.14
ฑ0.05
0.02
ฑ0.01
3.51
ฑ0.98
7.58
ฑ1.27
47.39
ฑ7.88
1.73
ฑ0.35
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of viewing.
NA = Not available due to the criteria for calculating a quarterly and/or annual average
Observations for BTUT from Table 24-5 include the following:
The pollutants with the highest annual average concentrations by mass are
dichloromethane, formaldehyde, acetaldehyde, and benzene, consistent with the last
few years of sampling. The annual average for dichloromethane is significantly
higher than the annual averages of the other pollutants.
Dichloromethane has the highest annual average for BTUT, but also has a very large
confidence interval associated it, as do the quarterly averages. This indicates the
likely presence of outliers. The concentrations of dichloromethane at BTUT range
from 0.313 |ig/m3to 1,214 |ig/m3. One measurement of this pollutant is greater than
1,000 |ig/m3, three are greater than 500 |ig/m3, six are greater than 75.0 |ig/m3, and
12 are greater than 10 |ig/m3. The top six measurements are the six highest
concentrations of dichloromethane measured across the program. However, the
median concentration of dichloromethane for BTUT is 0.919 |ig/m3, as over half of
the measurements are less than 1 |ig/m3.
There are no first quarter averages for the VOCs because sampler issues during this
time resulted in canisters with pressures outside of the tolerance limits.
The first quarter average concentrations of the three carbonyl compound pollutants of
interest are higher than the other quarterly averages and have relatively large
24-16
-------
confidence intervals. A review of the data shows that the highest concentrations of all
three pollutants were measured in February and March. The maximum concentration
of formaldehyde (19.9 |ig/m3) was measured at BTUT on March 4, 2011, which is the
day the second highest concentrations of acetaldehyde and propionaldehyde were
measured. This formaldehyde concentration is the second highest formaldehyde
concentration measured across the program. The maximum concentrations of
acetaldehyde (7.06 |ig/m3) and propionaldehyde (1.44 |ig/m3) were measured at
BTUT on February 26, 2011, which is the day the second highest concentration of
formaldehyde was measured. This propionaldehyde concentration is the highest
propionaldehyde concentration measured across the program (although a
concentration of similar magnitude was also measured at TOOK).
In addition to the first quarter, the second and third quarter average concentrations of
formaldehyde also have relatively large confidence intervals associated with them.
BTUT is the site with the highest number of formaldehyde measurements greater than
5 |ig/m3 (15), which were measured in February (5), March (3), June (3), and July (4).
Many of the VOC pollutants of interest are highest during the fourth quarter of 2011,
as illustrated by the quarterly averages. The highest concentrations of these pollutants
were measured in January, November, or December, or were detected most frequently
during these months. For example, 1,2-dichloroethane was detected 11 times (out of a
total of 15) during the fourth quarter and trichloroethylene was not detected outside
the first or fourth quarters. Of the eight benzene concentrations greater than 2 |ig/m3,
all but one was measured in January, November, or December. Similarly, of the
15 ethylbenzene concentrations greater than 0.5 |ig/m3, all but one was measured in
the first or fourth quarter of 2011. The 19 highest concentrations of 1,3-butadiene
were also measured in the first or fourth quarters of 2011.
Concentrations of naphthalene and benzo(a)pyrene appear highest in the colder
months of the year. The ten highest concentrations of naphthalene (those greater than
90 ng/m3) were all measured in the first and fourth quarters of 2011. Although
benzo(a)pyrene was detected in only 20 samples, 14 of these were measured during
the first and fourth quarters of 2011, with the highest concentrations measured during
these quarters.
This trend continues for some of the metals. The maximum concentrations of arsenic,
cadmium, and lead were all measured on January 15, 2011, with additional "higher"
concentrations measured in November and December. The arsenic concentration
measured on this date for BTUT is the maximum arsenic concentration measured
among sites sampling metals. A similar trend was noted in the 2010 NMP report. This
is not true for manganese, beryllium, or nickel.
Concentrations of hexavalent chromium ranged from 0.0055 ng/m3 to 0.13 ng/m3.
The maximum concentration of hexavalent chromium was measured at BTUT on
July 2, 2011, and is twice the next highest concentration (0.06 ng/m3, measured on
January 21, 2011).
24-17
-------
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for BTUT from
those tables include the following:
BTUT appears in Table 4-9 through 4-12 a total of 13 times for the program-lev el
pollutants of interest.
BTUT does not rank higher than eighth among the program-level VOC pollutants of
interest shown in Table 4-9.
BTUT has the highest annual average concentration of formaldehyde and tenth
highest annual average concentration of acetaldehyde among NMP sites sampling
carbonyl compounds, as shown in Table 4-10.
BTUT does not appear in Table 4-11 for PAHs. This site's annual average
concentrations of the PAHs are among the lower averages for sites sampling PAHs.
BTUT ranks in the top five for each of the PMio metals shown in Table 4-12. It is
important, however, to note that only nine sites sampled PMio metals. BTUT does not
appear in Table 4-12 for hexavalent chromium.
24.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde, arsenic,
benzene, benzo(a)pyrene, 1,3-butadiene, formaldehyde, hexavalent chromium, lead, manganese,
and naphthalene were created for BTUT. Figures 24-6 through 24-15 overlay the site's
minimum, annual average, and maximum concentrations onto the program-level minimum, first
quartile, median, average, third quartile, and maximum concentrations, as described in
Section 3.5.3.
Figure 24-6. Program vs. Site-Specific Average Acetaldehyde Concentration
Program:
Site:
1st Quartile
Site Average
0
2nd Quartile
3rd Quartile
n
4th Quartile Average
n
^m i i
Site Minimum/Maximum
24-18
-------
Figure 24-7. Program vs. Site-Specific Average Arsenic (PMi0) Concentration
0.5
1.5
2 2.5
Concentration (ng/mi)
3.5
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile 3rdQuartile 4thQuartile Ave
n
Site Minimum/Maximum
'rage
4.5
Figure 24-8. Program vs. Site-Specific Average Benzene Concentration
Program Max Concentration = 23.8 ug/n
456
Concentration (pg/mi)
10
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 24-9. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
0.75 1 1.25
Concentration (ng/mj)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
24-19
-------
Figure 24-10. Program vs. Site-Specific Average 1,3-Butadiene Concentration
B~U~
E
Program Max Concentration = 9.51 ng/m3
0.5
1.5
Concentration (jig/mi)
2.5
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
o
Figure 24-11. Program vs. Site-Specific Average Formaldehyde Concentration
10
15
Concentration [[Jg/m3)
IS
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
o
30
Figure 24-12. Program vs. Site-Specific Average Hexavalent Chromium Concentration
K
0.05
0.1
0.15
Concentration (ng/m3)
O.Z5
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
o
24-20
-------
Figure 24-13. Program vs. Site-Specific Average Lead (PMi0) Concentration
trir
10
15 20
Concentration (ng/mi)
25
35
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 24-14. Program vs. Site-Specific Average Manganese (PMi0) Concentration
E
; Program Max Concentration = 395 ng/m3 |
75
100
Concentration (ng/m3)
125
175
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
sec-
24-15. Program vs. Site-Specific Average Naphthalene Concentration
trir
Program Max Concentration =779 ng/m3
5:
100
150
200 250 300
Concentration (ng/m3)
350
400
453
sec-
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile SrdQuartile 4thQuartile Ave
Site Minimum/Maximum
rage
Observations from Figures 24-6 through 24-14 include the following:
Figure 24-6 shows that the annual average acetaldehyde concentration for BTUT
is just greater than the program-level average concentration. The maximum
concentration measured at BTUT is less than the maximum acetaldehyde
concentration measured at the program-level. There were no non-detects of
acetaldehyde measured at BTUT or across the program.
24-21
-------
Figure 24-7 shows that the maximum concentration of arsenic (PMio) across the
program was measured at BTUT. Yet, the annual average arsenic concentration is
equivalent to the program-level average arsenic concentration. Two non-detects of
arsenic were measured at BTUT.
Figure 24-8 is the box plot for benzene. Note that the program-level maximum
benzene concentration (23.8 |ig/m3) is not shown directly on the box plot because
the scale of the box plot would be too large to readily observe data points at the
lower end of the concentration range. Thus, the scale has been reduced to
10 |ig/m3. Figure 24-8 shows that the annual average concentration for BTUT is
greater than the program-level average concentration and third quartile
(75th percentile). The maximum concentration of benzene measured at BTUT is
considerably less than the maximum concentration measured across the program.
There were no non-detects of benzene measured at BTUT or across the program.
Figure 24-9 is the box plot for benzo(a)pyrene. Note that the program-level first
quartile for this pollutant is zero and is not visible on this box plot. The box plot
shows that the annual average concentration for BTUT is less than the program-
level average concentration but greater than the program-level median
concentration. Figure 24-9 also shows that the maximum concentration measured
at BTUT is considerably less than the maximum concentration measured across
the program. A number of non-detects of benzo(a)pyrene were measured at
BTUT.
Similar to the box plot for benzene, the program-level maximum 1,3-butadiene
concentration (9.51 |ig/m3) is not shown directly on the box plot in Figure 24-10;
thus, the scale has been reduced to 3 |ig/m3 in order to allow for the observation of
data points at the lower end of the concentration range. Figure 24-10 for
1,3-butadiene shows that the annual average concentration for BTUT is similar to
the program-level average concentration and that both are just less than the
program-level third quartile. The maximum concentration of 1,3-butadiene
measured at BTUT is considerably less than the maximum concentration
measured across the program. Several non-detects of 1,3-butadiene were
measured at BTUT.
Figure 24-11 shows that BTUT's annual average formaldehyde concentration is
greater than the program-level average and greater than the program-level third
quartile. Although the maximum concentration of formaldehyde measured at
BTUT is not the maximum measured across the program, it is the second highest
formaldehyde concentration measured among NMP sites sampling carbonyl
compounds. There were no non-detects of formaldehyde measured at BTUT or
across the program.
Figure 24-12 is the box plot for hexavalent chromium. The annual average
concentration for BTUT is less than the program-level average but greater than
the program-level median concentration. The maximum concentration measured
at BTUT is less than the program-level maximum concentration. There were a
few non-detects of hexavalent chromium measured at BTUT.
24-22
-------
Figure 24-13 shows that the annual average concentration of lead (PMio) for
BTUT is less than the program-level average concentration. Although the
maximum concentration measured at BTUT is less than the program-level
maximum concentration, it is the third highest lead concentration measured
among NMP sites sampling metals. There were no non-detects of lead measured
at BTUT or across the program.
Figure 24-14 is the box plot for manganese (PMio). The program-level maximum
manganese concentration (395 ng/m3) is not shown directly on the box plot as the
scale has been reduced to 200 ng/m3 in order to allow for the observation of data
points at the lower end of the concentration range. Figure 24-14 shows that the
annual average concentration of manganese (PMio) for BTUT is less than the
program-level average concentration. The maximum concentration measured at
BTUT is considerably less than the program-level maximum concentration.
Although difficult to discern in Figure 24-14, there were no non-detects of
manganese measured at BTUT.
Figure 24-15 is the box plot for naphthalene. The program-level maximum
naphthalene concentration (779 ng/m3) is not shown directly on the box plot in
Figure 24-15 as the scale has been reduced to 500 ng/m3 in order to allow for the
observation of data points at the lower end of the concentration range.
Figure 24-15 shows that the annual average naphthalene concentration for BTUT
is less than both the program-level average and median concentrations. Of the
23 sites sampling PAHs, the annual average concentration of naphthalene for
BTUT ranks 19th. The maximum naphthalene concentration measured at BTUT is
considerably less than the program-level maximum concentration. There were no
non-detects of naphthalene measured at BTUT or across the program.
24.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. BTUT has sampled carbonyl compounds, VOCs, metals, and SNMOCs as part of
the NMP since 2003. BTUT has also sampled hexavalent chromium since 2005. Thus,
Figures 24-16 through 24-23 present the annual statistical metrics for acetaldehyde, arsenic,
benzene, 1,3-butadiene, formaldehyde, hexavalent chromium, lead, and manganese for
BTUT, respectively. The statistical metrics presented for assessing trends include the substitution
of zeros for non-detects. Sampling for PAHs at BTUT did not begin until 2008; thus, a trends
analysis was not conducted for the PAHs because this method does not meet the 5 consecutive
year criteria.
24-23
-------
Figure 24-16. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at BTUT
2004 2005 2006 2007 2008 2009 2010 2011
Year
# 5th Percentile Minimum Median Maximum 95th Percentile .. + .. Average
Figure 24-17. Annual Statistical Metrics for Arsenic (PMio) Concentrations
Measured at BTUT
1
|l2
B
a
i
3
1
o -
The maximum arsenic j
concentration for
*..
" i i A
2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile - Minimum Median Maximum 95th Percentile ...+*. Average
24-24
-------
Figure 24-18. Annual Statistical Metrics for Benzene Concentrations Measured at BTUT
'm
.a b
1
i
I 4 -
3 4
1
la
i -
-
i
^ , 1-,
r
I
,_
E r
^^ [
* ^
""^** * *" ^^ * A
-- f r-
^ta
| 1 L_^ , t- z E
2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median - Maximum 95th Percentile +*^.. Average
Figure 24-19. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at BTUT
tration (ME/i
3 i
1
3
EO 3 -
S
o -
'
*"
^^
2004
.4 *'
(
..
T
3
T
" r~^
* t , ป-
^^^ -+ ^....^ - ป ป
^^^^^ ^^^^i
f
2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Max mum 95th Percentile ..+.. Average
24-25
-------
Figure 24-20. Annual Statistical Metrics for Formaldehyde Concentrations Measured at
BTUT
t
B
a
!25
1
3
8,n -
c 20
5 -
I
1
20
[ r-I-,
1
T
at* <*-...
-1 L-t-1 PT5 e^3 P55 ^^ HP
04 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile Minimum Median Maximum 95th Percentile + Average
Figure 24-21. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at BTUT
0.5
0.45
0.4
0.35
E
"5 0.3
s
.:
S 0.25
1
3
|o,
ฃ
<
0.15
0.1
0.05
0
T
[
T T
_
^... .-^ .....j.^... ^^.. ..^^ ....^^ ^
2005 2006 2007 2003 2009 2010 2011
Year
5th Percentile - Minimum Median Maximum 95th Percentile ..+** Average
24-26
-------
Figure 24-22. Annual Statistical Metrics for Lead (PMi0) Concentrations
Measured at BTUT
I15
B
a
S
I
8
2004 2005 2006 2007 200B 2009 2010 2011
Year
5th Percentile - Minimum Median Maximum 95th Percentile "^"Average
Figure 24-23. Annual Statistical Metrics for Manganese (PMio) Concentrations
Measured at BTUT
2004 2005 2006 2007 2008 2009 2010 2011
Year
5th Percentile - Minimum Median - Maximum 95th Percentile "-4*+Average
24-27
-------
Observations from Figure 24-16 for acetaldehyde measurements include the following:
Although sampling for carbonyl compounds at BTUT began in 2003, sampling did
not begin until July, which does not yield enough samples for the statistical metrics to
be calculated, based on the criteria specified in Section 3.5.4. Thus, Figure 24-16
begins with 2004.
The maximum acetaldehyde concentration was measured in 2004 (32.7 |ig/m3). The
second highest concentration of acetaldehyde measured at BTUT is the maximum
shown for 2008 (20.0 |ig/m3). All acetaldehyde concentrations greater than 8 |ig/m3
were measured prior to 2009.
The average concentration exhibits a steady decreasing trend beginning with 2006
and continuing through 2009, after which the average concentration held steady
around 2 |ig/m3.
Even with the second highest concentration measured (20.0 |ig/m3), nearly all of the
statistical metrics exhibit a decrease from 2007 to 2008. The second highest
concentration measured in 2008 (4.17 |ig/m3) was considerably less than the
maximum concentration and only five acetaldehyde concentrations greater than
3 |ig/m3 were measured that year, which is the least of any year of sampling.
There have been no non-detects of acetaldehyde measured at BTUT.
Observations from Figure 24-17 for arsenic measurements include the following:
Although sampling for PMio metals at BTUT began in 2003, sampling did not begin
until July, which does not yield enough samples for the statistical metrics to be
calculated, based on the criteria specified in Section 3.5.4. Thus, Figure 24-17 begins
with 2004.
The maximum arsenic concentration was measured in 2004. The maximum
concentration measured (33.0 ng/m3) is nearly twice the next highest concentration
(16.8 ng/m3), also measured in 2004. The three highest measurements of arsenic were
all measured at BTUT in 2004; further, eight of the 12 highest concentrations of
arsenic (those greater than 5 ng/m3) were measured in 2004. Of these 12, eight were
measured in the first quarter of the calendar year and four were measured during the
fourth quarter of the calendar year, supporting the tendency discussed in
Section 24.4.1.
The average concentration of arsenic decreased significantly from 2004 to 2005, a
trend that continued into 2006. After 2004, the average arsenic concentration has
fluctuated between 0.59 ng/m3 (2011) to 1.13 ng/m3 (2009). The statistical parameters
for 2007 and 2009 are being driven primarily by a single "high" measurement. If
2007 and 2009 are excluded, the averages then range from 0.59 ng/m3 to 0.71 ng/m3.
If the maximum concentrations measured in 2007 and 2009 were removed, the
average concentrations from 2005 to 2011 would all be less than 1 ng/m3. The
maximum concentrations for 2007 and 2009 were both measured in January.
24-28
-------
Non-detects of arsenic were not measured for half of the years of sampling. For those
years with non-detects, the greatest percentage were measured in 2011 (5 percent).
Observations from Figures 24-18 for benzene include the following:
Although sampling for VOCs at BTUT began in 2003, sampling did not begin until
July, which does not yield enough samples for the statistical metrics to be calculated,
based on the criteria specified in Section 3.5.4. Thus, Figure 24-18 begins with 2004.
The maximum concentration of benzene shown was measured in 2009 (8.16 |ig/m3).
The next highest concentration (6.56 |ig/m3) was also measured in 2009, although
concentrations greater than 6 |ig/m3 were also measured in 2005 and 2007.
The average and median concentrations have a decreasing trend through 2007. An
increasing trend in the average is then shown through 2009, after which another
decreasing trend follows. The average benzene concentration ranges from 1.14 |ig/m3
(2011)tol.87|ig/m3(2004).
Although the average concentration increased for 2009, the median concentration
decreased. This average is being driven by the higher concentrations measured in
2009, as discussed above.
There have been no non-detects of benzene measured at BTUT.
Observations from Figures 24-19 for 1,3-butadiene include the following:
The maximum concentration of 1,3-butadiene shown was measured in 2005
(0.75 |ig/m3). The second highest concentration was also measured in 2005
(0.53 |ig/m3), although a similar measurement was also collected in 2006. These are
the only concentrations of 1,3-butadiene greater than 0.5 |ig/m3.
The minimum, 5th percentile, and median concentrations are all zero for the 2004,
indicating that at least 50 percent of the measurements were non-detects. The
detection rate of 1,3-butadiene increased after 2004, as indicated by the increase in
the median concentration and then the 5th percentile. The percentage of non-detects
decreased from 75 percent for 2004 to 0 percent for 2008 and 2009. The percentage
of non-detects increased to 7 percent for 2010 and 18 percent for 2011.
The average concentration has changed little over the years of sampling and ranges
from 0.10 |ig/m3 to 0.12 |ig/m3 between 2005 and 2011.
24-29
-------
Observations from Figure 24-20 for formaldehyde measurements include the following:
The maximum formaldehyde concentration was measured in 2004 (45.4 |ig/m3), on
the same day as the highest acetaldehyde concentration, August 31, 2004. This
measurement is more than twice the next highest concentration (19.9 |ig/m3),
measured in 2011. Concentrations greater than 15 |ig/m3 were measured in 2004,
2005, 2006, 2007, and 2011.
Although the maximum concentration decreased significantly from 2004 to 2005, the
other statistical metrics exhibit an increase from 2004 to 2005. The median, or
midpoint concentration, increased by 2 |ig/m3 from 2004 to 2005, indicating that
concentrations ran higher in 2005 than 2004 rather than being driven by an outlier, as
in 2004. As an illustration, there were 11 concentrations greater than 5 |ig/m3 in 2004
compared to 31 in 2005.
After 2005, the average concentration began to decrease, reaching a minimum for
2008. A steady increasing trend in the average formaldehyde concentration, as well as
most other statistical parameters, is shown after 2008.
Although the maximum, 95th percentile, and average concentrations increased for
2011, the median actually decreased. Although the concentrations on the upper end of
the range are higher than they had been in recent years of sampling, the number of
concentrations on the lower end of the range is also higher for 2011. The number of
measurements less than 2.5 |ig/m3 for 2011 (30) is the second highest, behind only
2008 (37).
There have been no non-detects of formaldehyde measured at BTUT.
Observations from Figure 24-21 for hexavalent chromium measurements include the
following:
The maximum hexavalent chromium concentration was measured on July 4, 2006
(0.45 ng/m3). The next highest concentration, measured in 2010, is roughly half as
high.
The minimum and 5th percentile are both zero for each year of sampling, indicating
the presence of non-detects. The number of non-detects has varied over the years,
ranging from eight percent (2006) to 38 percent (2009). The decrease exhibited by
most of the statistical metrics from 2008 to 2009 may result, at least in part, from the
increase in non-detects (up from 10 percent 2008), and thus, zeros substituted into the
calculations.
The average hexavalent chromium concentration has fluctuated over the years of
sampling, ranging from 0.019 ng/m3 for 2009 to 0.037 ng/m3 for 2008.
24-30
-------
Observations from Figure 24-22 for lead measurements include the following:
Although the maximum concentration of lead was measured in 2011 (23.2 ng/m3),
similar concentrations were also measured in 2004 and 2009.
The statistical metrics shown in Figure 24-22 reflect a relatively high level of
variability in the lead concentrations measured at BTUT. One indicator of this is the
difference between the average and median concentrations. This difference is at a
minimum for 2008 (0.22 ng/m3) and at a maximum for 2009 (1.33 ng/m3), with a
difference for half of the years of sampling greater than 1 ng/m3.
The average and median concentrations have an overall decreasing trend over the
period of sampling, although this is difficult to discern in Figure 24-22 due to the
fluctuations in the maximum concentrations and 95th percentiles.
Observations from Figure 24-23 for manganese measurements include the following:
The maximum manganese concentration (40.4 ng/m3) was measured in 2004,
although the next highest concentration, measured in 2007, is similar in magnitude
(36.0 ng/m3). Concentrations greater than 20 ng/m3 have been measured in 2004,
2007, 2008, 2009, and 2011.
The average concentration decreased from 2004 to 2005, after which an increase is
shown through 2007, although these changes are not statistically significant.
However, a significant decrease in manganese concentrations is shown from 2008
through 2010. The median concentration follows a similar trend.
With the exception of the 5th percentile, all of the statistical metrics exhibit an
increase for 2011. The number of concentrations greater than 10 ng/m3 increased
from six in 2010 to 18 in 2011.
24.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
BTUT monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations regarding
the various toxicity factors, time frames, and calculations associated with these risk-based
screenings.
24.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Utah monitoring site to the ATSDRMRLs, where available. As described in Section 3.3, MRLs
are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
24-31
-------
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites are greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
24.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for BTUT and where annual average concentrations could
be calculated, risk was examined by calculating cancer risk and noncancer hazard
approximations. These approximations can be used as risk estimates for cancer and noncancer
effects attributable to the pollutants of interest. Although the use of these approximations is
limited, they may help identify where policy-makers may want to shift or confirm their air-
monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer risk and
noncancer hazard approximations are calculated and what limitations are associated with them.
Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer hazard
approximations are presented in Table 24-6, where applicable. Cancer risk approximations are
presented as probabilities while the noncancer hazard approximations are ratios and thus, unitless
values.
Table 24-6. Risk Approximations for the Utah Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(jig/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Bountiful, Utah - BTUT
Acetaldehyde
Acrylonitrile
Arsenic (PM10)a
Benzene
Benzo(a)pyrenea
Beryllium (PM10)a
0.0000022
0.000068
0.0043
0.0000078
0.00176
0.0024
0.009
0.002
0.000015
0.03
0.00002
60/60
7/60
58/60
60/60
20/62
53/60
2.19
ฑ0.35
0.02
ฑ0.01
<0.01
ฑ<0.01
1.14
ฑ0.15
<0.01
ฑ<0.01
0.01
ฑ0.01
4.83
1.10
2.52
8.90
0.08
0.03
0.24
0.01
0.04
0.04
0.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 24-5.
24-32
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Table 24-6. Risk Approximations for the Utah Monitoring Site (Continued)
Pollutant
1,3 -Butadiene
Cadmium (PM10)a
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Dichloromethane
Ethylbenzene
Formaldehyde
Hexachloro- 1 ,3 -butadiene
Hexavalent Chromium3
Lead (PM10)a
Manganese (PM10)a
Naphthalene3
Nickel (PM10)a
Propionaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Cancer
URE
(Hg/m3)1
0.00003
0.0018
0.000006
0.000011
0.000026
0.00000013
0.0000025
0.000013
0.000022
0.012
0.000034
0.00048
0.00000026
0.0000048
0.0000088
Noncancer
RfC
(mg/m3)
0.002
0.00001
0.1
0.098
0.8
2.4
0.6
1
0.0098
0.09
0.0001
0.00015
0.00005
0.003
0.00009
0.008
0.04
0.002
0.1
#of
Measured
Detections
vs. # of
Samples
49/60
60/60
60/60
29/60
29/60
15/60
60/60
60/60
60/60
6/60
53/61
60/60
60/60
62/62
60/60
60/60
41/60
11/60
1/60
Annual
Average
(Hg/m3)
0.10
ฑ0.02
0.01
ฑ0.01
0.61
ฑ0.03
0.06
ฑ0.02
0.05
ฑ0.02
0.03
ฑ0.01
53.90
ฑ 50.64
0.47
ฑ0.13
4.49
ฑ1.15
0.01
ฑ0.01
0.01
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
0.05
ฑ0.01
0.01
ฑ0.01
0.46
ฑ0.07
0.10
ฑ0.02
0.02
ฑ0.01
0.01
ฑ0.01
Cancer Risk
Approximation
(in-a-million)
2.98
0.25
3.68
0.50
0.72
7.01
1.17
58.42
0.22
0.26
1.61
0.83
0.03
0.07
0.01
Noncancer
Hazard
Approximation
(HQ)
0.05
0.01
0.01
O.01
0.01
O.01
0.09
O.01
0.46
O.01
0.01
0.02
0.15
0.02
0.02
0.06
0.01
0.01
0.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 24-5.
Observations for BTUT from Table 24-6 include the following:
The pollutants with the highest annual average concentrations are dichloromethane,
formaldehyde, acetaldehyde, and benzene, as discussed in Section 24.4.1.
The pollutants with the highest cancer risk approximations are formaldehyde,
benzene, dichloromethane, and acetaldehyde. The cancer risk approximation for
24-33
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formaldehyde is eight times greater than the cancer risk approximation for
dichloromethane, even with an annual average concentration of dichloromethane
nearly 12 times greater than the annual average concentration of formaldehyde. This
is an indication of the toxicity potential of formaldehyde vs. dichloromethane.
There were no pollutants of interest with noncancer hazard approximations greater
than 1.0, indicating that no adverse health effects are expected from these individual
pollutants. The highest noncancer hazard approximation was calculated for
formaldehyde (0.46), which is the second highest noncancer hazard approximation
calculated among the site-specific pollutants of interest with noncancer toxicity
factors.
24.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 24-7 and 24-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 24-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 24-6. Table 24-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 24-6.
The pollutants listed in Tables 24-7 and 24-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 24.3, BTUT sampled for VOCs, carbonyl compounds, SNMOCs, metals (PMio), PAHs,
and hexavalent chromium. In addition, the cancer risk and noncancer hazard approximations are
limited to those pollutants with enough data to meet the criteria for annual averages to be
calculated. A more in-depth discussion of this analysis is provided in Section 3.5.5.3. Similar to
the cancer risk and noncancer hazard approximations, this analysis may help policy-makers
prioritize their air monitoring activities.
24-34
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Table 24-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Utah Monitoring Site
to
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Bountiful, Utah (Davis County) - BTUT
Benzene
Ethylbenzene
Formaldehyde
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
POM, Group la
POM, Group 6
174.72
80.37
76.71
44.32
20.55
10.19
2.66
1.59
0.20
0.14
Benzene
Formaldehyde
1,3 -Butadiene
Naphthalene
Ethylbenzene
POM, Group 3
POM, Group 2b
Hexavalent Chromium, PM
Acetaldehyde
POM, Group 5a
1.36E-03
9.97E-04
6.17E-04
3.46E-04
2.01E-04
1.87E-04
1.40E-04
1.31E-04
9.75E-05
7.17E-05
Formaldehyde
Benzene
Dichloromethane
Acetaldehyde
Carbon Tetrachloride
1,3 -Butadiene
Arsenic
Naphthalene
Ethylbenzene
Acrylonitrile
58.42
8.90
7.01
4.83
3.68
2.98
2.52
1.61
1.17
1.10
-------
Table 24-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Utah Monitoring Site
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer
Hazard
Approximation
(HQ)
Bountiful, Utah (Davis County) - BTUT
Toluene
Xylenes
Benzene
Methanol
Hexane
Ethylbenzene
Formaldehyde
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
403.75
329.01
174.72
171.92
100.56
80.37
76.71
44.32
22.52
20.55
Acrolein
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Naphthalene
Xylenes
Lead, PM
Arsenic, PM
Propionaldehyde
215,538.97
10,275.13
7,827.57
5,823.93
4,924.23
3,395.03
3,290.06
1,295.06
736.79
619.63
Formaldehyde
Acetaldehyde
Manganese
Dichloromethane
Propionaldehyde
1,3 -Butadiene
Arsenic
Benzene
Lead
Nickel
0.46
0.24
0.15
0.09
0.06
0.05
0.04
0.04
0.02
0.02
to
-------
Observations from Table 24-7 include the following:
Benzene, ethylbenzene, and formaldehyde are the highest emitted pollutants with
cancer UREs in Davis County.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
cancer UREs) are benzene, formaldehyde, 1,3-butadiene.
Seven of the highest emitted pollutants also have the highest toxi city-weighted
emissions.
Formaldehyde and benzene, which have the highest and second highest cancer risk
approximations for BTUT, appear near the top of both emissions-based lists.
Acetaldehyde, 1,3-butadiene, naphthalene, and ethylbenzene also appear on all three
lists in Table 24-7. Dichloromethane, which has the third highest cancer risk
approximation for BTUT, ranks seventh for emissions in Davis County but does not
have one of the highest toxicity-weighted emissions (it ranks 19th). Carbon
tetrachloride, which has the fifth highest cancer risk approximation for BTUT,
appears on neither emissions-based list.
POM, Group 2b is the eighth highest emitted "pollutant" in Davis County and ranks
seventh for toxicity-weighted emissions. POM, Group 2b includes several PAHs
sampled for at BTUT including acenaphthylene, fluoranthene, and perylene. None of
the PAHs included in POM, Group 2b failed screens for BTUT.
POM, Group 5a ranks tenth for toxicity-weighted emissions in Davis County. POM,
Group 5a includes benzo(a)pyrene, which is one of BTUT's pollutants of interest.
POM, Group 5a is not one of the highest emitted pollutants in Davis County and is
not among the pollutants with the highest cancer risk approximations for BTUT.
Observations from Table 24-8 include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs in Davis County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, 1,3-butadiene, and formaldehyde. Although acrolein
was sampled for at BTUT, this pollutant was excluded from the pollutants of interest
designation, and thus subsequent risk-based screening evaluations, due to questions
about the consistency and reliability of the measurements, as discussed in Section 3.2.
Five of the highest emitted pollutants also have the highest toxicity-weighted
emissions.
Although less than 1.0, formaldehyde, acetaldehyde, and manganese have the highest
noncancer hazard approximations for BTUT. Formaldehyde and acetaldehyde rank
third and fifth (respectively) for toxicity-weighted emissions and seventh and eighth
24-37
-------
(respectively) for total emissions. Dichloromethane, which has the fourth highest
noncancer hazard approximation, appears on neither emissions-based list.
24.6 Summary of the 2011 Monitoring Data for BTUT
Results from several of the data treatments described in this section include the
following:
ปซป Twenty-one pollutants failed at least one screen for BTUT; of these, 12 were NATTS
MQO Core Analytes.
ปซป Dichloromethane had the highest annual average concentration among the pollutants
of interest for BTUT, followed by formaldehyde, acetaldehyde, and benzene.
ปซป The annual average formaldehyde concentration for BTUT is the highest annual
average among NMP sites sampling carbonyl compounds.
ปซป Formaldehyde concentrations at BTUT have been increasing in the last few years of
sampling while benzene concentrations have decreased in the last few years. There is
an overall decreasing trend in concentrations of lead at BTUT.
24-38
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25.0 Sites in Vermont
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the UATMP and NATTS sites in Vermont, and integrates these
concentrations with emissions, meteorological, and risk information. Data generated by sources
other than ERG are not included in the data analyses contained in this report. Readers are
encouraged to refer to Sections 1 through 4 and the glossary (Appendix P) for detailed
discussions and definitions regarding the various data analyses presented below.
25.1 Site Characterization
This section characterizes the Vermont monitoring sites by providing geographical and
physical information about the location of the sites and the surrounding areas. This information
is provided to give the reader insight regarding factors that may influence the air quality near the
sites and assist in the interpretation of the ambient monitoring measurements.
The Vermont NATTS site (UNVT) and one of the UATMP sites (BURVT) are located in
northwest Vermont in the Burlington-South Burlington, VT MSA. The third site is located
farther south in Rutland, Vermont. Figures 25-1 and 25-2 are the composite satellite images
retrieved from ArcGIS Explorer showing the Burlington monitoring sites in their urban and rural
locations. Figure 25-3 identifies nearby point source emissions locations by source category, as
reported in the 2008 NEI for point sources. Note that only sources within 10 miles of the sites are
included in the facility counts provided in Figure 25-3. A 10-mile boundary was chosen to give
the reader an indication of which emissions sources and emissions source categories could
potentially have a direct effect on the air quality at the monitoring sites. Further, this boundary
provides both the proximity of emissions sources to the monitoring sites as well as the quantity
of such sources within a given distance of the sites. Sources outside the 10-mile radii are still
visible on the map, but have been grayed out in order to show emissions sources just outside the
boundary. Figures 25-4 and 25-5 are the composite satellite image and emissions sources map
for the Rutland site. Table 25-1 provides supplemental geographical information such as land
use, location setting, and locational coordinates.
25-1
-------
Figure 25-1. Burlington, Vermont (BURVT) Monitoring Site
to
-------
Figure 25-2. Underbill, Vermont (UNVT) Monitoring Site
to
I
OJ
-------
Figure 25-3. NEI Point Sources Located Within 10 Miles of BURVT and UNVT
73-Sf-W 73'OX-W TZ'WOTW 72-5trtn/V TJ'45'CTW 72'WCrW
Legend
ฉ BURVT UATMP site
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
UNVT NATTS site O 10 mile radius f 1 County boundary
Source Category Group (No. of Facilities)
-f1 Aircraft Operations (13)
e Electrical Equipment (2)
& Institutional - school (1)
ฎ Laboratory (1)
A Military Base/National Security Facility (1)
Electricity Generation via Combustion (2) M Miscellaneous Manufacturing (1)
Gasoline/Diesel Service Station (1 )
4 Hot Mix Asphalt Plant (1)
% Industrial Machinery and Equipment (2)
1 Primary Metal Production (1)
P Printing/Publishing (2)
TI Telecommunications (1)
25-4
-------
Figure 25-4. Rutland, Vermont (RUVT) Monitoring Site
to
I
(^
-------
Figure 25-5. NEI Point Sources Located Within 10 Miles of RUVT
TS'lO'tTW 73 S'O'W 73"0'(TW
72'50'CTVV 72-45'Q'W
73-151TW 73MO-0-W
Legend
73'5'O-W TJ'OtrW TTteWt 72-SOXnW
Note: Due to facility density and collocation, the total facilities
displayed may not represent all facilities within the area of interest.
RUVT UATMP site 10 mile radius | | County boundary
Source Category Group (No. of Facilities)
* Aerospace/Aircraft Manufacturing (2)
-fr1 Aircraft Operations (4)
o Clay Ceramics Manufacturing (1)
ป Hot Mix Asphalt Plant (1)
5 Miscellaneous Coating Manufacturing (1}
Plywood, Particleboard, OSB (1)
H Pulp and Paper Plant/Wood Products (1)
w Woodwork, Furniture, Millwork & Wood Preserving (1)
25-6
-------
Table 25-1. Geographical Information for the Vermont Monitoring Sites
Site
Code
BURVT
RUVT
UNVT
AQS Code
50-007-0014
50-021-0002
50-007-0007
Location
Burlington
Rutland
Underbill
County
Chittenden
Rutland
Chittenden
Micro- or
Metropolitan
Statistical Area
Burlington-South
Burlington, VT
MSA
Rutland, VT MSA
Burlington-South
Burlington, VT
MSA
Latitude
and
Longitude
44.476202,
-73.210383
43.608056,
-72.982778
44.52839,
-72.86884
Land Use
Commercial
Commercial
Forest
Location
Setting
Urban/City
Center
Urban/City
Center
Rural
Additional Ambient Monitoring Information1
CO, NO, NO2, NOX, Carbonyl compounds,
Meteorological parameters, PM10, PM25.
CO, SO2, NO, NO2, NOX, Carbonyl compounds,
Meteorological parameters, PM10, PM25.
Haze, Sulfate, SO2, O3, Meteorological parameters,
PM10, PM Coarse, PM25, and PM25 Speciation.
Data for additional pollutants are reported to AQS for these sites (EPA, 2012c); however, these data are not generated by ERG and are therefore not included in this report
BOLD ITALICS = EPA-designated NATTS Site
to
-------
BURVT is located in a municipal parking lot in downtown Burlington near the
intersection of Main Street and South Winooski Avenue. This location is less than 1 mile east of
Burlington Bay on Lake Champlain. The areas to the west are commercial while the areas to the
east are residential, as shown in Figure 25-1. Route 2 (Main Street) and Route 7 (South Willard
Street) intersect two blocks east of the monitoring site and 1-89 runs north-south just over 1 mile
east of the site. Between the two roadways and the interstate lies the University of Vermont.
The UNVT monitoring site is located on the Proctor Maple Research Farm in Underhill,
Vermont, which is east of the Burlington area. Mount Mansfield, the highest peak in Vermont,
lies to the east in Underhill State Park, less than 3 miles away. The Underhill Artillery Range is a
few miles to the south. Figure 25-2 shows that the area surrounding the site is rural in nature and
heavily forested. This site is intended to serve as a background site for the region for trends
assessment, standards compliance, and long-range transport assessment.
As Figure 25-3 shows, UNVT and BURVT are located approximately 16 miles apart.
Most of the emissions sources are located between these two sites, although closer to BURVT.
The source category with the greatest number of emissions sources surrounding these sites is the
aircraft operations source category, which includes airports as well as small runways, heliports,
or landing pads. The sources closest to BURVT are a medical school/hospital, an airport, and
two facilities generating electricity via combustion. The sources closest to UNVT are private
airports.
The RUVT monitoring site is located in Rutland, in central Vermont. The city of Rutland
is in a valley between the Green Mountains to the east and Taconic Mountains to the west. The
monitoring site is located in the courthouse parking lot in downtown Rutland, just north of West
Street. Commercial areas are located to the east and south, while residential areas are located to
the north and west, as shown in Figure 25-4. A railway parallels Route 4 coming into Rutland
from the west, crosses under Route 4, then meanders around a shopping plaza just south of
Route 4. The north junction of Route 4 and Route 7 is approximately 1/2 mile east of the site.
Figure 25-5 shows that most of the emissions sources near RUVT are located along Route 4 and
Route 7, just south of the monitoring site. The source categories with the greatest number of
sources include aircraft operations and aerospace/aircraft manufacturing. The source closest to
RUVT is an aerospace/aircraft manufacturer.
25-8
-------
Table 25-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Vermont monitoring sites. Table 25-2 includes county-level
population and vehicle registration information. Table 25-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within each monitoring site's residing county. In addition, the population within 10 miles
of each site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was then determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding each monitoring site. Table 25-2 also
contains traffic volume information for each site. Finally, Table 25-2 presents the county-level
daily VMT for Chittenden and Rutland Counties.
Table 25-2. Population, Motor Vehicle, and Traffic Information for the Vermont
Monitoring Sites
Site
BURVT
UNVT
RUVT
Estimated
County
Population1
157,491
61,289
County-level
Vehicle
Registration2
169,767
70,900
Vehicles per
Person
(Registration:
Population)
1.08
1.16
Population
within 10
miles3
120,787
33,622
34,662
Estimated
10-mile
Vehicle
Ownership
130,202
36,243
40,098
Annual
Average
Daily
Traffic4
14,000
1,110
7,200
County-
level Daily
VMT5
4,027,945
1,766,027
Bounty-level population estimates reflect 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2012 data from the Vermont DMV (VT DMV, 2012)
310-mile population estimates reflect 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2007 and 2011 data for BURVT and UNVT, respectively, from the Chittenden County Regional
Planning Commission (CCRPC, 2007 and 2011) and 2010 data for RUVT from Vermont Agency of
Transportation (VTrans, 2011)
5County-level VMT reflects 2010 data from the Vermont Agency of Transportation (Vtrans, 2010)
BOLD ITALICS = EPA-designaled NATTS Site
Observations from Table 25-2 include the following:
The population for Chittenden County is more than twice the population of Rutland
County. The populations for both counties are in the bottom third compared to other
counties with NMP sites. UNVT's 10-mile population is the lowest among the three
Vermont sites, although it is similar to the 10-mile population surrounding RUVT.
The 10-mile populations for BURVT and UNVT show that BURVT is near the center
of population for Chittenden County while UNVT is not.
Although similar patterns are shown in the vehicle ownership data, the number of
vehicles registered in each county is higher than the population counts, leading to
relatively large vehicle-per-person ratios. This indicates that some people own more
than one vehicle.
25-9
-------
The traffic volume is highest near BURVT and lowest near UNVT among the
Vermont sites. The traffic estimates near these sites are in the bottom third compared
to the traffic near other NMP sites. The traffic estimate for BURVT is provided for
Main Street between South Union Street and South Willard Street; Pleasant Valley
Road, north of Harvey Road for UNVT; and US-4 Business between Merchants Row
and Grove Street for RUVT.
Even though the county-level daily VMT for Chittenden County is more than twice
the VMT for Rutland County, both VMTs are in the bottom third compared to other
counties with NMP monitoring sites (where VMT data were available).
25.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
sites in Vermont on sample days, as well as over the course of the year.
25.2.1 Climate Summary
The city of Burlington resides just to the east of Lake Champlain in northwest Vermont.
Lake Champlain has a moderating affect on the city, keeping the city slightly warmer in winter
than it could be given its New England location. The town of Underhill is located to the east of
Burlington but still within the Burlington MSA. The city of Rutland is located 60 miles south of
the Burlington area. Rutland resides within the same climatic division of Vermont as Burlington,
but misses the moderating influences of Lake Champlain. The state of Vermont is affected by
most storm systems that track across the country, producing variable weather and often cloudy
skies. Summers in Vermont are pleasant, with warm days and cool nights, escaping much of the
heat and humidity much of the East Coast experiences. Winters are warmer in the Champlain
Valley region than in other portions of the state but snow is common state-wide. Precipitation is
evenly distributed throughout the year. Average annual winds parallel the valleys, generally from
the south ahead of advancing weather systems, or from the north behind these systems. These
storm systems tend to be moderated somewhat due to the Adirondacks to the west and Green
Mountains to the east (Bair, 1992; NCDC, 2013; NOAA, 2013c).
25-10
-------
25.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather stations nearest the Vermont
monitoring sites were retrieved for 2011 (NCDC, 2011). The closest weather station to BURVT
is located at Burlington International Airport; nearest RUVT is Rutland State Airport; and
nearest UNVT is Morrisville-Stowe State Airport (WBANs 14742, 94737, and 54771,
respectively). Additional information about these weather stations, such as the distance between
the sites and the weather stations, is provided in Table 25-3. These data were used to determine
how meteorological conditions on sample days vary from conditions experienced throughout the
year.
Table 25-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year for 2011. Also included in Table 25-3 is the
95 percent confidence interval for each parameter. As shown in Table 25-3, average
meteorological conditions on sample days at UNVT were representative of average weather
conditions throughout the year. Temperatures on sample days at BURVT and RUVT appear
slightly warmer than those for all of 2011, although the differences are not statistically
significant.
25.2.3 Back Trajectory Analysis
Figure 25-6 is the composite back trajectory map for days on which samples were
collected at the BURVT monitoring site in 2011. Included in Figure 25-6 are four back
trajectories per sample day. Figure 25-7 is the corresponding cluster analysis. Similarly,
Figures 25-8 through 25-11 are the composite back trajectory maps and corresponding cluster
analyses for RUVT and UNVT. An in-depth description of these maps and how they were
generated is presented in Section 3.5.2.1. For the composite maps, each line represents the
24-hour trajectory along which a parcel of air traveled toward the monitoring site on a given
sample day and time, based on an initial height of 50 meters AGL. For the cluster analyses, each
line corresponds to a trajectory representative of a given cluster of back trajectories. Each
concentric circle around the sites in Figures 25-6 through 25-11 represents 100 miles.
25-11
-------
Table 25-3. Average Meteorological Conditions near the Vermont Monitoring Sites
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar
Wind
Speed
(kt)
Burlington, Vermont - BURVT
Burlington Intl.
Airport
14742
(44.48, -73.16)
2.38
miles
87ฐ
(E)
Sample
Day
2011
57.4
ฑ7.3
55.9
ฑ2.2
48.9
ฑ6.7
47.9
ฑ2.0
39.1
ฑ6.7
38.2
ฑ2.0
44.4
ฑ6.2
43.5
ฑ1.9
71.9
ฑ4.7
71.7
ฑ1.2
1015.5
ฑ3.1
1014.9
ฑ0.8
6.4
ฑ1.1
6.3
ฑ0.3
Rutland, Vermont - RUVT
Rutland State Airport
94737
(43.53, -72.95)
5.60
miles
149ฐ
(SSE)
Sample
Day
2011
56.6
ฑ6.1
54.8
ฑ2.0
48.9
ฑ5.8
46.4
ฑ1.9
39.1
ฑ6.2
36.4
ฑ2.0
44.4
ฑ5.5
41.9
ฑ1.8
71.4
ฑ4.4
70.3
ฑ1.2
NA
NA
6.6
ฑ1.0
6.1
ฑ0.3
Underbill, Vermont - UNVT
Morrisville - Sto we
State Airport
54771
(44.53, -72.61)
11.84
miles
78ฐ
(E)
Sample
Day
2011
54.1
ฑ4.7
54.7
+ 2.2
44.9
ฑ4.2
45.1
+ 2.0
36.5
ฑ4.4
36.7
+ 2.1
41.2
ฑ4.0
41.3
+ 1.9
74.9
ฑ2.7
75.1
+ 1.1
1015.9
ฑ1.8
1015.6
+ 0.8
3.2
ฑ0.5
3.0
+ 0.2
to
NA = Sea level pressure was not recorded at the Rutland State Airport
-year averages.
-------
Figure 25-6. 2011 Composite Back Trajectory Map for BURVT
Figure 25-7. Back Trajectory Cluster Map for BURVT
25-13
-------
Figure 25-8. 2011 Composite Back Trajectory Map for RUVT
Figure 25-9. Back Trajectory Cluster Map for RUVT
25-14
-------
Figure 25-10. 2011 Composite Back Trajectory Map for UNVT
Figure 25-11. Back Trajectory Cluster Map for UNVT
25-15
-------
Observations from Figures 25-6 through 25-11 for the Vermont monitoring sites include
the following:
The composite back trajectories maps for the Vermont sites are similar to each other,
which is not unexpected given their relatively close proximity to each other.
However, BURVT and RUVT sampled on a l-in-12 schedule, yielding roughly half
as many sample days for these sites as UNVT.
The composite back trajectory maps show that the majority of back trajectories
originated from a direction with a westerly component.
For BURVT and RUVT, the farthest away a back trajectory originated was over
south-central Ontario, Canada, or greater than 500 miles away. For UNVT, the
farthest away a back trajectory originated was central West Virginia, or nearly
600 miles away. The average trajectory length varied from 220 miles for RUVT to
231 miles for BURVT and UNVT. Most back trajectories (roughly 90 percent)
originated within 400 miles of each site.
The cluster analyses for BURVT and RUVT are fairly similar to each other
direct! onally, although the percentages vary. For BURVT, 34 percent of back
trajectories originated to the north of the site, generally over Quebec, Canada. For
RUVT, this percentage is 26 percent. Between 7 and 9 percent of back trajectories
originated to the west of the sites over the Greater Lakes region and southern Ontario,
Canada. For BURVT, 30 percent of back trajectories originated from the southwest
quadrant, including south and west, primarily over New York and Pennsylvania. For
RUVT, this percentage is higher, at 41 percent. The cluster trajectory originating to
the east of the sites and representing about one-quarter of the back trajectories,
includes longer back trajectories originating over the Atlantic Ocean, shorter
trajectories originating over New Hampshire, as well as trajectories originating from
other directions but generally less than 100 miles in length.
The back trajectories for UNVT are represented by five cluster trajectories rather than
four in Figure 25-11. Twenty-eight percent of back trajectories originated to the
northwest of UNVT and another seven percent originated to the north to northeast of
UNVT. These back trajectories are combined in the cluster analyses for BURVT and
RUVT. Twenty percent of back trajectories originated to the southwest to west of
UNVT over the Great Lakes region and southern Ontario, Canada. Just less than one-
quarter of back trajectories originated to the south to southwest of UNVT over the
Northeast and Mid-Atlantic states. The same percentage of back trajectories is
represented by the short cluster trajectory originating over New Hampshire. Similar to
the other two Vermont sites, this cluster trajectory represents longer back trajectories
originating over the Atlantic Ocean, shorter trajectories originating over the New
England states, as well as back trajectories originating from other directions but
generally less than 100 miles in length.
25-16
-------
25.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather stations at Burlington International
Airport (for BURVT), Rutland State Airport (for RUVT), and Morrisville-Stowe State Airport
(for UNVT) were uploaded into a wind rose software program to produce customized wind
roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions using
"petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 25-12 presents a map showing the distance between the NWS station and
BURVT, which may be useful for identifying topographical influences that may affect the
meteorological patterns experienced at this location. Figure 25-12 also presents three different
wind roses for the BURVT monitoring site. First, a historical wind rose representing 2001 to
2010 wind data is presented, which shows the predominant surface wind speed and direction
over an extended period of time. Second, a wind rose representing wind observations for all of
2011 is presented. Next, a wind rose representing wind data for days on which samples were
collected in 2011 is presented. These can be used to identify the predominant wind speed and
direction in 2011 and determine if wind observations on sample days were representative of
conditions experienced over the entire year and historically. Figures 25-13 and 25-14 present the
three wind roses and distance maps for the RUVT and UNVT monitoring sites.
Observations from Figure 25-12 for BURVT include the following:
The Burlington International Airport weather station is located approximately
2.8 miles east of BURVT.
The historical wind rose shows that southerly winds are prevalent near BURVT,
accounting for nearly 22 percent of the hourly measurements. Calm winds (< 2 knots)
account for another 19 percent of measurements. Winds from the northwest quadrant,
including north, account for another 30 percent of the wind observations. Winds from
the eastern quadrants are rarely observed.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, indicating that conditions observed during 2011 were similar to those
observed over the last 10 years.
The sample day wind rose shows that wind conditions on sample days were similar to
those experienced throughout 2011, although northwesterly to northerly winds
accounted for a higher percentage of the hourly wind measurements.
25-17
-------
Figure 25-12. Wind Roses for the Burlington International Airport Weather Station
near BURVT
Distance between BURVT and NWS Station
2001-2010 Historical Wind Rose
* . *
... bid, V S
, Ellington ^*v X 5_
' .? j -
2011 Wind Rose
Sample Day Wind Rose
25-18
-------
Figure 25-13. Wind Roses for the Rutland State Airport Weather Station near RUVT
Distance between RUVT and NWS Station
2003-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
25-19
-------
Figure 25-14. Wind Roses for the Morrisville-Stowe State Airport Weather Station near
UNVT
Distance between UNVT and NWS Station
2001-2010 Historical Wind Rose
N
+
2011 Wind Rose
Sample Day Wind Rose
25-20
-------
Observations from Figure 25-13 for RUVT include the following:
The Rutland State Airport weather station is located approximately 5.6 miles south-
southeast of RUVT.
The historical wind rose shows that east-southeasterly and southeasterly winds were
prevalent near RUVT, as these directions account for over a quarter of the hourly
measurements. Winds from the southwest and northwest quadrants were also
observed while winds from the northeast quadrant were almost never observed. Calm
winds were observed for 17 percent of the hourly measurements.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, although a higher percentage of winds from the southeast and fewer east-
southeasterly winds were observed in 2011.
The sample day wind rose exhibits similar wind patterns as the historical and full-
year wind roses, but with even fewer east-southeasterly winds and more south-
southeasterly and southerly wind observations.
Observations from Figure 25-14 for UNVT include the following:
The Morrisville-Stowe Airport weather station is located approximately 12 miles east
of UNVT. Between the site and the weather station lie the Green Mountains.
The historical wind rose shows that calm winds were prevalent near UNVT, as calm
winds were observed for nearly 45 percent of the hourly measurements. Winds from
the northwest to north account for 20 percent of the wind observations greater than
2 knots. Winds from the south to south-southwest account for another 15 percent of
observations.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, although calm winds account for almost 50 percent of the observations.
The sample day wind rose shows that wind conditions on sample days were similar to
those experienced throughout 2011, although winds from the northwest to north
account for a greater percentage of wind measurements on sample days.
25.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Vermont monitoring sites in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
For each site, each pollutant's preprocessed daily measurement was compared to its associated
risk screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by each monitoring site did not
25-21
-------
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 25-4 presents the results of the preliminary risk-based screening process for the
Vermont monitoring sites. The pollutants that failed at least one screen and contributed to 95
percent of the total failed screens for each monitoring site are shaded. NATTS MQO Core
Analytes are bolded. Thus, pollutants of interest are shaded and/or bolded. BURVT and RUVT
sampled for VOCs only while UNVT sampled for VOCs, hexavalent chromium, PAHs, and
metals (PMio).
Table 25-4. Risk-Based Screening Results for the Vermont Monitoring Sites
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Burlington, Vermont - BURVT
Benzene
1,3-Butadiene
Carbon Tetrachloride
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
Acrylonitrile
Ethylbenzene
1, 1,2,2-Tetrachloroethane
Bromomethane
1 ,2-Dibromoethane
0.13
0.03
0.17
0.091
0.038
0.045
0.015
0.4
0.017
0.5
0.0017
Total
30
30
30
7
7
5
4
4
4
1
1
123
30
30
30
27
7
6
4
30
4
22
1
191
100.00
100.00
100.00
25.93
100.00
83.33
100.00
13.33
100.00
4.55
100.00
64.40
24.39
24.39
24.39
5.69
5.69
4.07
3.25
3.25
3.25
0.81
0.81
24.39
48.78
73.17
78.86
84.55
88.62
91.87
95.12
98.37
99.19
100.00
Rutland, Vermont - RUVT
Benzene
Carbon Tetrachloride
1,3-Butadiene
1 ,2-Dichloroethane
Ethylbenzene
Acrylonitrile
Hexachloro- 1 ,3 -butadiene
0.13
0.17
0.03
0.038
0.4
0.015
0.045
Total
30
30
25
4
4
2
1
96
30
30
25
4
30
2
1
122
100.00
100.00
100.00
100.00
13.33
100.00
100.00
78.69
31.25
31.25
26.04
4.17
4.17
2.08
1.04
31.25
62.50
88.54
92.71
96.88
98.96
100.00
25-22
-------
Table 25-4. Risk-Based Screening Results for the Vermont Monitoring Sites (Continued)
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
%of
Total
Failures
Cumulative
%
Contribution
Underbill, Vermont - UNVT
Benzene
Carbon Tetrachloride
Arsenic (PM10)
1 ,2-Dichloroethane
Acrylonitrile
1,3-Butadiene
Naphthalene
Hexachloro- 1 ,3 -butadiene
Manganese (PM10)
1 , 1 ,2,2-Tetrachloroethane
Bromomethane
ฃ>-Dichlorobenzene
Nickel (PM10)
0.13
0.17
0.00023
0.038
0.015
0.03
0.029
0.045
0.005
0.017
0.5
0.091
0.0021
Total
60
58
23
12
6
5
4
3
3
2
1
1
1
179
60
60
54
12
6
13
60
4
57
2
28
10
57
423
100.00
96.67
42.59
100.00
100.00
38.46
6.67
75.00
5.26
100.00
3.57
10.00
1.75
42.32
33.52
32.40
12.85
6.70
3.35
2.79
2.23
1.68
1.68
1.12
0.56
0.56
0.56
33.52
65.92
78.77
85.47
88.83
91.62
93.85
95.53
97.21
98.32
98.88
99.44
100.00
Observations from Table 25-4 include the following:
A total of 11 pollutants, including three NATTS MQO Core Analytes, failed screens
for BURVT. Seven pollutants, including the same three NATTS MQO Core
Analytes, failed screens for RUVT. The seven pollutants failing screens for RUVT
also failed at least one screen for BURVT. Thirteen pollutants, of which seven are
NATTS MQO Core Analytes, failed screens for UNVT.
The preliminary risk-based screening process identified nine pollutants of interest for
BURVT. Even though the 95 percent criteria is met by ethylbenzene,
1,1,2,2-tetrachloroethane contributed equally to the number of failed screens (4), thus,
this pollutant was also designated as a pollutant of interest, as discussed in
Section 3.2. Four additional pollutants (chloroform, tetrachloroethylene, and
trichloroethylene, and vinyl chloride) were added as pollutants of interest for BURVT
because they are NATTS MQO Core Analytes, even though these pollutants did not
fail any screens. These pollutants are not shown in Table 25-4 but are shown in
subsequent tables in the sections that follow.
The preliminary risk-based screening process identified five pollutants of interest for
RUVT (benzene, carbon tetrachloride, 1,3-butadiene, 1,2-dichloroethane, and
ethylbenzene). Three additional pollutants (chloroform, tetrachloroethylene, and
trichloroethylene) were added as pollutants of interest because they are NATTS MQO
Core Analytes, even though these pollutants did not fail any screens. These pollutants
are not shown in Table 25-4 but are shown in subsequent tables in the sections that
follow. Vinyl chloride is also a NATTS MQO Core Analyte, but because this
pollutant was not detected at RUVT, it was not added to the pollutants of interest.
25-23
-------
The preliminary risk-based screening process identified nine pollutants of interest for
UNVT (six VOCs, two metals, and one PAH). Nickel was added to UNVT's
pollutants of interest because it is a NATTS MQO Core Analyte, even though it did
not contribute to 95 percent of UNVT's total failed screens. Nine additional
pollutants (three PMi0 metals, four VOCs, one PAH, and hexavalent chromium) were
added as pollutants of interest for UNVT because they are NATTS MQO Core
Analytes, even though these pollutants did not fail any screens. These pollutants are
not shown in Table 25-4 but are shown in subsequent tables in the sections that
follow.
Benzene, carbon tetrachloride, 1,3-butadiene, and 1,2-dichloroethane were identified
as pollutants of interest for each of the Vermont monitoring sites.
25.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Vermont monitoring sites. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for the Vermont sites, where the data meet the applicable criteria.
Concentration averages for select pollutants are also presented graphically for each site to
illustrate how the sites' concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the sites. Additional site-
specific statistical summaries for BURVT, RUVT, and UNVT are provided in Appendices J, M,
N,and O.
25.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for each Vermont site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for the Vermont
25-24
-------
monitoring sites are presented in Table 25-5, where applicable. Note that concentrations of the
PAHs, metals, and hexavalent chromium for UNVT are presented in ng/m3 for ease of viewing.
Also note that if a pollutant was not detected in a given calendar quarter, the quarterly average
simply reflects "0" because only zeros substituted for non-detects were factored into the
quarterly average concentration.
Table 25-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Vermont Monitoring Sites
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(jig/m3)
2nd
Quarter
Average
(jig/m3)
3rd
Quarter
Average
(jig/m3)
4th
Quarter
Average
(jig/m3)
Annual
Average
(jig/m3)
Burlington, Vermont - BURVT
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
ฃ>-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Hexachloro-1 ,3 -butadiene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
4/30
30/30
30/30
30/30
17/30
27/30
7/30
30/30
6/30
4/30
23/30
2/30
1/30
0.01
ฑ0.03
0.99
ฑ0.18
0.11
ฑ0.03
0.49
ฑ0.08
0.05
ฑ0.05
0.07
ฑ0.03
0
0.28
ฑ0.06
0.03
ฑ0.05
0.01
ฑ0.02
0.11
ฑ0.06
0
0
0.03
ฑ0.06
0.61
ฑ0.13
0.09
ฑ0.03
0.58
ฑ0.10
0.07
ฑ0.05
0.08
ฑ0.03
0.02
ฑ0.03
0.25
ฑ0.08
0.01
ฑ0.03
0
0.06
ฑ0.06
0.01
ฑ0.01
0
0.05
ฑ0.11
0.75
ฑ0.19
0.10
ฑ0.03
0.65
ฑ0.04
0.08
ฑ0.07
0.07
ฑ0.03
0.01
ฑ0.02
0.35
ฑ0.09
0.01
ฑ0.02
0.01
ฑ0.02
0.18
ฑ0.21
0
<0.01
ฑ0.01
0
0.79
ฑ0.15
0.10
ฑ0.03
0.62
ฑ0.07
0.08
ฑ0.05
0.06
ฑ0.01
0.04
ฑ0.03
0.32
ฑ0.08
0.02
ฑ0.03
0.01
ฑ0.02
0.13
ฑ0.06
0.01
ฑ0.01
0
0.02
ฑ0.03
0.78
ฑ0.09
0.10
ฑ0.01
0.59
ฑ0.04
0.07
ฑ0.02
0.07
ฑ0.01
0.02
ฑ0.01
0.30
ฑ0.04
0.02
ฑ0.01
0.01
ฑ0.01
0.12
ฑ0.05
0.01
ฑ0.01
O.01
ฑ0.01
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
25-25
-------
Table 25-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Vermont Monitoring Sites (Continued)
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Rutland, Vermont - RUVT
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
Tetrachloroethylene
Trichloroethylene
30/30
25/30
30/30
9/30
4/30
30/30
23/30
2/30
0.98
ฑ0.21
0.11
ฑ0.05
0.54
ฑ0.02
0
0
0.25
ฑ0.06
0.09
ฑ0.03
0
0.70
ฑ0.39
0.05
ฑ0.03
0.60
ฑ0.07
0.05
ฑ0.05
0.02
ฑ0.03
0.25
ฑ0.06
0.14
ฑ0.12
O.01
ฑ0.01
0.71
ฑ0.06
0.07
ฑ0.02
0.60
ฑ0.12
0.07
ฑ0.07
0
0.33
ฑ0.02
0.09
ฑ0.06
0
1.26
ฑ0.38
0.17
ฑ0.08
0.68
ฑ0.08
0.05
ฑ0.06
0.02
ฑ0.03
0.38
ฑ0.13
0.14
ฑ0.03
O.01
ฑ0.01
0.89
ฑ0.16
0.09
ฑ0.03
0.61
ฑ0.04
0.04
ฑ0.03
0.01
ฑ0.01
0.30
ฑ0.04
0.12
ฑ0.04
O.01
ฑO.01
Underbill, Vermont - UNVT
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Hexachloro- 1 , 3 -butadiene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (PM10)a
Benzo(a)pyrene a
Bery Ilium (PM10)a
6/60
60/60
13/60
60/60
17/60
12/60
4/60
19/60
1/60
1/60
55/58
13/60
46/58
0.01
ฑ0.01
0.59
ฑ0.11
0.01
ฑ0.01
0.46
ฑ0.09
0.03
ฑ0.02
O.01
ฑ0.01
0.01
ฑ0.02
0.03
ฑ0.02
0
0
0.23
ฑ0.10
0.04
ฑ0.03
0.01
ฑO.01
0.01
ฑ0.01
0.33
ฑ0.03
0.01
ฑ0.01
0.54
ฑ0.09
0.03
ฑ0.03
0.02
ฑ0.02
0.01
ฑ0.02
0.01
ฑ0.01
0
0.01
ฑ0.01
0.19
ฑ0.08
0.01
ฑ0.01
0.01
ฑO.01
0.01
ฑ0.01
0.31
ฑ0.06
0.01
ฑ0.01
0.63
ฑ0.04
0.01
ฑ0.02
0
0.01
ฑ0.01
0.02
ฑ0.02
0
0
NA
0
NA
0.01
ฑ0.02
0.43
ฑ0.06
0.01
ฑ0.01
0.64
ฑ0.05
0.03
ฑ0.02
0.04
ฑ0.02
O.01
ฑ0.01
0.02
ฑ0.02
O.01
ฑO.01
0
0.31
ฑ0.12
0.01
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
0.42
ฑ0.04
0.01
ฑ0.01
0.57
ฑ0.04
0.03
ฑ0.01
0.02
ฑ0.01
0.01
ฑ0.01
0.02
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
0.25
ฑ0.06
0.01
ฑ0.01
0.01
ฑO.01
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
25-26
-------
Table 25-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Vermont Monitoring Sites (Continued)
Pollutant
Cadmium (PM10)a
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
#of
Measured
Detections
vs. # of
Samples
58/58
17/60
58/58
58/58
60/60
58/58
1st
Quarter
Average
(Ug/m3)
0.07
ฑ0.03
<0.01
ฑ<0.01
1.50
ฑ0.64
1.37
ฑ0.42
27.87
ฑ 12.64
0.45
ฑ0.29
2nd
Quarter
Average
(Ug/m3)
0.05
ฑ0.01
0.01
ฑ0.01
0.94
ฑ0.27
2.06
ฑ0.70
6.43
ฑ1.53
0.33
ฑ0.09
3rd
Quarter
Average
(Ug/m3)
NA
<0.01
ฑ<0.01
NA
NA
5.44
ฑ1.68
NA
4th
Quarter
Average
(Ug/m3)
0.08
ฑ0.03
<0.01
ฑ<0.01
1.88
ฑ0.54
2.00
ฑ0.63
13.23
ฑ4.58
0.74
ฑ0.15
Annual
Average
(Ug/m3)
0.07
ฑ0.01
<0.01
ฑ<0.01
1.46
ฑ0.29
1.84
ฑ0.32
13.37
ฑ3.96
0.53
ฑ0.10
NA = Not available due to the criteria for calculating a quarterly and/or annual average.
a Average concentrations provided for the pollutants below the blue line are presented in ng/m3 for ease of
viewing.
Observations for BURVT and RUVT from Table 25-5 include the following:
BURVT and RUVT sampled VOCs on a l-in-12 day schedule.
For both sites, the pollutants with the highest annual average concentrations are
benzene, carbon tetrachloride, and ethylbenzene, although all of the annual average
concentrations for the pollutants of interest for both sites are less than 1 |ig/m3.
Several of the VOCs listed for BURVT were detected relatively few times, resulting
in relatively large confidence intervals for the quarterly and annual averages, some of
which are greater than the averages themselves. Examples include acrylonitrile,
1,2-dichloroethane, hexachloro-l,3-butadiene, and 1,1,2,2-tetrachloroethane. This is
also true from some of RUVT's pollutants of interest.
The first quarter benzene average for BURVT is higher than the other quarterly
averages. A review of the data shows that the maximum concentration of benzene
was measured on February 2, 2011 (1.38 |ig/m3). Of the five benzene concentrations
greater than 1 |ig/m3 measured at BURVT, three were measured in the first quarter of
2011 (with one each measured in the third and fourth quarter).
The third quarter average concentration of tetrachloroethylene for BURVT is greater
than the other quarterly averages and has a confidence interval that is greater than the
averages itself. A review of the data shows that the maximum concentration of
tetrachloroethylene was measured on September 24, 2011 (0.75 |ig/m3), which is
more than twice the next highest concentration (0.31 |ig/m3, measured on
October 6, 2011). All other measurements of tetrachloroethylene are 0.20 |ig/m3 or
less.
25-27
-------
Several of the quarterly averages of benzene for RUVT have relatively large
confidence intervals associated with them. Concentrations of benzene measured at
RUVT range from 0.311 |ig/m3 to 2.07 |ig/m3. The maximum benzene concentration
was measured on June 17, 2011 and is the only concentration of benzene greater than
1 |ig/m3 measured in the second quarter. A total of eight benzene concentrations
greater than 1 |ig/m3 were measured at RUVT, with two measured in the first quarter,
one (the maximum) was measured in the second, and five were measured in the
fourth quarter.
Although the second and fourth quarter average concentrations of tetrachloroethylene
are the same for RUVT, the second quarter average has a larger confidence interval
associated with it. A review of the data shows that the three highest concentrations of
tetrachloroethylene were measured in April, May, and June. These are three of only
four measurements greater than 0.20 |ig/m3 measured at this site (with the fourth
being measured in October).
Observations for UNVT from Table 25-5 include the following:
UNVT sampled VOCs, PAHs, PMio metals, and hexavalent chromium on a l-in-6
day schedule.
Carbon tetrachloride and benzene have highest annual average concentrations.
Similar to BURVT and RUVT, all of the annual average concentrations for the
pollutants of interest for UNVT are less than 1 |ig/m3.
Of the metals, manganese and lead have the highest annual average concentrations.
For the PAHs, naphthalene has the highest annual average concentration.
The first quarter benzene average for UNVT is higher than the other quarterly
averages, although the differences are not statistically significant. The maximum
concentration of benzene was measured on February 27, 2011 (1.31 |ig/m3) and is the
only benzene measurement greater than 1 |ig/m3. The second highest benzene
concentration measured at UNVT was collected on the following sample day and was
half as high (0.755 |ig/m3). Of the 16 measurements greater than 0.5 |ig/m3, 11 were
measured during the first quarter, one was measured in third quarter, and four were
measured during the fourth quarter.
Similar to the other Vermont sites, several of the VOCs listed for UNVT were
detected relatively few times, resulting in relatively large confidence intervals for the
quarterly and annual averages. Examples include acrylonitrile, 1,2-dichloroethane,
and hexachloro-1,3-butadiene.
Third quarter averages for the PMio metals are not provided in Table 25-5. This is a
result of flooding and damage to the metals sampler as well as the Vermont
Department of Conservation laboratory in the wake of Hurricane Irene at the end of
August 2011. While a few missed samples are noted for all methods sampled at
UNVT, metals were the most affected because individual samples were lost in the
flood at the laboratory.
25-28
-------
Concentrations of naphthalene at UNVT tended to be higher during the colder months
of the year. The maximum concentration of naphthalene was measured at UNVT on
January 27, 2011 (85.8 ng/m3). The three highest concentrations of naphthalene were
measured at UNVT in January and February and of the 15 highest concentrations
(those greater than 15 ng/m3), 10 were measured during the first quarter of the year
and the other five were measured during the fourth quarter of 2011.
The first quarter benzo(a)pyrene average for UNVT is higher than the other quarterly
averages and has a relatively large confidence interval associated with it. The
maximum concentration of this pollutant (0.162 ng/m3) was measured on
January 21, 2011 and is one of only three concentrations greater than 0.1 ng/m3
measured at UNVT. These three measurements were made on the same days as the
highest naphthalene concentrations.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for the Vermont
monitoring sites from those tables include the following:
BURVT appears twice in Table 4-9 for VOCs. BURVT has the second highest annual
average concentration of hexachloro-l,3-butadiene and the tenth highest annual
average concentration ofp-dichlorobenzene among NMP sites sampling VOCs.
RUVT appears once in Table 4-9. RUVT has the tenth highest annual average
concentration of benzene among NMP sites sampling VOCs.
UNVT appears only in Table 4-12 for PMio metals. However, because only nine
NMP sites sampled PMio metals, all nine sites appear in Table 4-12. UNVT ranks
eighth or ninth for each of the six program-wide metal pollutants of interest.
Compared to other NMP sites, UNVT has some of the lowest annual average
concentrations for each of the program-wide pollutants of interest. For the VOCs,
UNVT ranks no higher than 16th. For the PAHs and hexavalent chromium, UNVT
ranks last for each pollutant.
25.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzene and 1,3-butadiene
were created for BURVT, RUVT, and UNVT. Box plots were also created for arsenic,
benzo(a)pyrene, hexavalent chromium, manganese, lead, and naphthalene for UNVT.
Figures 25-15 through 25-22 overlay the sites' minimum, annual average, and maximum
concentrations onto the program-level minimum, first quartile, median, average, third quartile,
and maximum concentrations, as described in Section 3.5.3.
25-29
-------
Figure 25-15. Program vs. Site-Specific Average Arsenic (PMi0) Concentration
UNVT
3.5
15
2 Z.5
Concentration (ng/m3)
3.5
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
4.5
Figure 25-16. Program vs. Site-Specific Average Benzene Concentrations
i Program Max Concentration = 23.8 ug/m3
! Program Max (
1 1
-,
i Program Max Concentration = 23.8 |-ig/m-
45
Concentration (t
Progra m :
Site:
IstQuartile
Site Average
0
2ndQuartile
SrdQuartile
n
4thQuartile Average
n
^m i i
Site Minimum/Maximum
10
Figure 25-17. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
0.75 1
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site:
Site Average Site Minimum/Maximum
25-30
-------
Figure 25-18. Program vs. Site-Specific Average 1,3-Butadiene Concentrations
E
Program Max Concentration = 3.51 ug/m3
RUVT
| Program Max Concentration = 9.51 Lig/m3
I
0
^^^ ^^^
0.5 1 1.5
Concentration (|jg/m3)
Program: IstQuartile 2ndQuartile SrdQuartile
Site: Site Average Site Minimum/Maximum
o
Program Max Concentration = 9.51 ng/m3
2
4thQuartile Av(
15
;rage
3
Figure 25-19. Program vs. Site-Specific Average Hexavalent Chromium Concentration
D.I
3.15
Concentration (ng/m3)
:.=
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 25-20. Program vs. Site-Specific Average Lead (PMio) Concentration
15 20
Concentration (ng/m3)
Program
Site:
: IstQuartile
Site Average
O
2ndQuartile SrdQuartile 4thQuartile Ave
n
Site Minimum/Maximum
rage
25-31
-------
Figure 25-21. Program vs. Site-Specific Average Manganese (PMi0) Concentration
UNVT
1
! Program Max ConcEntration = 395 ng/m3
i
75 100 125
Concentration (ng/mi)
150
175
200
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 25-22. Program vs. Site-Specific Average Naphthalene Concentration
i Program Max Concentration =779 ng/m-
200 250 3OO
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Observations from Figures 25-15 through 25-22 include the following:
Figure 25-15 shows that UNVT's annual average arsenic (PMio) concentration is
roughly equivalent to the program-level first quartile (25th percentile). The annual
average concentration of arsenic for UNVT is the lowest annual average
concentration among NMP sites sampling this pollutant. The maximum arsenic
concentration measured at UNVT is less than the program-level average
concentration. A few non-detects of arsenic were measured at UNVT.
Figure 25-16 for benzene shows all three Vermont sites. Note that the program-
level maximum concentration (23.8 |ig/m3) is not shown directly on the box plots
because the scale of the box plots would be too large to readily observe data
points at the lower end of the concentration range. Thus, the scale has been
reduced to 10 |ig/m3. This figure shows that the annual average concentration of
benzene is highest for RUVT and lowest for UNVT and that all three annual
averages are less than the program-level average benzene concentration.
Figure 25-16 also shows that UNVT's annual average benzene concentration is
less than the program-level average, median, and first quartile concentrations (and
is the second lowest among all NMP sites sampling benzene). The range of
benzene measurements is smallest for BURVT and largest for RUVT, although
there were no non-detects of benzene measured at the Vermont sites. Note that the
minimum benzene concentration across the program was measured at UNVT.
25-32
-------
Figure 25-17 is the box plot for benzo(a)pyrene for UNVT. Note that the first
quartile for this pollutant is zero and is not visible on the box plot. This box plot
shows that the annual average concentration for UNVT is less than the program-
level average and median concentrations. The maximum concentration measured
at UNVT is considerably less than the maximum concentration measured across
the program. Nearly 80 percent of the measurements at UNVT were non-detects.
Figure 25-18 for 1,3-butadiene also shows all three sites. Similar to the benzene
box plots, the program-level maximum concentration (9.51 |ig/m3) is not shown
directly on the box plots as the scale has been reduced to 3 |ig/m3 in order to
allow for the observation of data points at the lower end of the concentration
range. The annual average concentration for BURVT is similar to the annual
average for RUVT, even though the range of measurements is higher for RUVT,
and both are roughly equivalent to the program-level average concentration. The
annual average for UNVT is an order of magnitude lower than the other two
Vermont sites. The maximum concentration measured at each site is considerably
less than the maximum 1,3-butadiene concentration measured across the program.
Five non-detects of 1,3-butadiene were measured at RUVT and 80 percent of the
measurements were non-detects for UNVT. Conversely, the minimum
concentration of 1,3-butadiene measured at BURVT is equivalent to the program-
level median concentration.
Figure 25-19 is the box plot for hexavalent chromium for UNVT. This figure
shows that the annual average concentration of hexavalent chromium for UNVT
is less than the program-level first quartile and is the lowest annual average
hexavalent chromium concentration among NMP sites sampling this pollutant.
The maximum concentration measured at UNVT is just greater than the program-
level average concentration. Nearly 70 percent of the measurements of hexavalent
chromium were non-detects.
Figure 25-20 is the box plot for lead (PMio) for UNVT. This figure shows that the
annual average concentration of lead for UNVT is just less than the program-level
first quartile and is the lowest annual average lead concentration among NMP
sites sampling this pollutant. The maximum concentration measured at UNVT is
the lowest maximum concentration among NMP sites sampling lead. The
minimum concentration measured at UNVT is the lowest minimum concentration
among NMP sites sampling lead.
Figure 25-21 is the box plot for manganese (PMio) for UNVT. Note that the
program-level maximum concentration (395 ng/m3) is not shown directly on the
box plot as the scale has been reduced to 200 ng/m3 in order to allow for the
observation of data points at the lower end of the concentration range. This figure
shows that, similar to other metals, the annual average concentration of
manganese (PMio) for UNVT is less than the program-level first quartile. The
annual average concentration of manganese for UNVT is the lowest annual
average concentration among NMP sites sampling this pollutant. There were no
non-detects of manganese measured at UNVT.
25-33
-------
Figure 25-22 is the box plot for naphthalene for UNVT. Note that the program-
level maximum concentration (799 ng/m3) is not shown directly on the box plot as
the scale has been reduced to 500 ng/m3 in order to allow for the observation of
data points at the lower end of the concentration range. The annual average for
UNVT is less than the program-level first quartile and ranks lowest among all
sites sampling this pollutant. The maximum naphthalene concentration measured
at UNVT is less than the program-level third quartile and just greater than the
program-level average concentration. It is also the lowest maximum concentration
among NMP sites sampling naphthalene.
25.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. UNVT has sampled hexavalent chromium under the NMP since 2005. Thus,
Figure 25-23 presents the annual statistical metrics for hexavalent chromium for UNVT. The
statistical metrics presented for calculating trends include the substitution of zeros for non-
detects. Sampling of the other methods did not begin until 2008 and thus does not meet the
5-consecutive year criterion.
Figure 25-23. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at UNVT
5th Percentile Minimum Median Maximum
95th Percentile
* Average
25-34
-------
Observations from Figure 25-23 for hexavalent chromium measurements at UNVT
include the following:
The maximum hexavalent chromium concentration was measured at UNVT on
June 16, 2006 (0.399 ng/m3). The next highest hexavalent chromium concentration
was measured on April 22, 2005 (0.101 ng/m3). All other measurements of this
pollutant are less than 0.1 ng/m3.
For all time frames shown, the minimum, 5th percentile, and median concentrations
are zero, indicating that at least 50 percent of the measurements are non-detects. The
percentage of non-detects has varied over the years of sampling, from as low as
63 percent in 2006 to as high as 95 percent in 2009.
The second highest concentration measured in 2006 is an order of magnitude less
than the maximum concentration measured that year. The 95th percentile decreased by
almost half from 2005 to 2006. Both are an indication that the maximum
concentration is driving the average concentration measured at UNVT for 2006. If
this measurement were removed from the calculations, Figure 25-23 would show a
decreasing trend beginning with 2006.
The average concentration decreased from 2006 to 2007 and again in 2008. Fewer
than 10 percent of the samples collected in 2008 and 2009 had measurable levels of
hexavalent chromium, which explains why even the average and 95th percentile are
nearly zero for these years. The number of non-detects decreased for 2010 and 2011
to between 70 and 80 percent, allowing the average concentration to increase. The
average concentrations for 2010 and 2011 are around 0.004 ng/m3.
25.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
Vermont monitoring sites. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
25.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Vermont monitoring sites to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
25-35
-------
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
25.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Vermont sites and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 25-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
Observations from Table 25-6 include the following:
For BURVT, benzene and carbon tetrachloride have the highest annual average
concentrations. These two pollutants also have the highest cancer risk approximations
for BURVT (6.08 in-a-million and 3.52 in-a-million, respectively).
Similar to BURVT, benzene and carbon tetrachloride have the highest annual average
concentrations for RUVT. These two pollutants also have the highest cancer risk
approximations for RUVT (6.94 in-a-million and 3.65 in-a-million, respectively).
Carbon tetrachloride and benzene have the highest annual average concentrations for
UNVT. These two pollutants also have the highest cancer risk approximations for
UNVT (3.41 in-a-million and 3.25 in-a-million, respectively).
The noncancer hazard approximations for the pollutants of interest for all three
Vermont sites are all considerably less than 1.0, indicating that no adverse health
effects are expected from these individual pollutants.
25-36
-------
Table 25-6. Risk Approximations for the Vermont Monitoring Sites
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Burlington, Vermont - BURVT
Acrylonitrile
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
p-Dichlorobenzene
1 ,2-Dichloroethane
Ethylbenzene
Hexachloro- 1 , 3 -butadiene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.000068
0.0000078
0.00003
0.000006
0.000011
0.000026
0.0000025
0.000022
0.000058
0.00000026
0.0000048
0.0000088
0.002
0.03
0.002
0.1
0.098
0.8
2.4
1
0.09
0.04
0.002
0.1
4/30
30/30
30/30
30/30
17/30
27/30
7/30
30/30
6/30
4/30
23/30
2/30
1/30
0.02
ฑ0.03
0.78
ฑ0.09
0.10
ฑ0.01
0.59
ฑ0.04
0.07
ฑ0.02
0.07
ฑ0.01
0.02
ฑ0.01
0.30
ฑ0.04
0.02
ฑ0.01
0.01
ฑ0.01
0.12
ฑ0.05
<0.01
ฑ<0.01
0.01
ฑ0.01
1.60
6.08
2.98
3.52
0.77
0.47
0.75
0.41
0.41
0.03
0.02
0.01
0.01
0.03
0.05
0.01
O.01
0.01
0.01
O.01
0.01
0.01
O.01
0.01
Rutland, Vermont - RUVT
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000078
0.00003
0.000006
0.000026
0.0000025
0.00000026
0.0000048
0.0000088
0.03
0.002
0.1
0.098
2.4
1
0.04
0.002
0.1
30/30
25/30
30/30
9/30
4/30
30/30
23/30
2/30
0/30
0.89
ฑ0.16
0.09
ฑ0.03
0.61
ฑ0.04
0.04
ฑ0.03
0.01
ฑ0.01
0.30
ฑ0.04
0.12
ฑ0.04
0.01
ฑ0.01
O.01
ฑO.01
6.94
2.80
3.65
0.29
0.76
0.03
0.01
O.01
0.03
0.05
0.01
0.01
O.01
0.01
O.01
0.01
O.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 25-5.
25-37
-------
Table 25-6. Risk Approximations for the Vermont Monitoring Sites (Continued)
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Underbill, Vermont - UNVT
Acrylonitrile
Arsenic (PM10)a
Benzene
Benzo(a)pyrene a
Beryllium (PM10) a
1,3 -Butadiene
Cadmium (PM10)a
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Hexachloro- 1 ,3 -butadiene
Hexavalent Chromium a
Lead(PM10)a
Manganese (PM10)a
Naphthalene a
Nickel (PM10)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.000068
0.0043
0.0000078
0.00176
0.0024
0.00003
0.0018
0.000006
0.000026
0.000022
0.012
0.000034
0.00048
0.00000026
0.0000048
0.0000088
0.002
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
2.4
0.09
0.0001
0.00015
0.00005
0.003
0.00009
0.04
0.002
0.1
6/60
54/57
60/60
13/60
45/57
13/60
57/57
60/60
17/60
12/60
4/60
17/60
57/57
57/57
60/60
57/57
19/60
1/60
1/60
0.01
ฑ0.01
0.01
ฑ<0.01
0.42
ฑ0.04
<0.01
ฑ<0.01
0.01
ฑ0.01
0.01
ฑ0.01
0.01
ฑ0.01
0.57
ฑ0.04
0.03
ฑ0.01
0.02
ฑ0.01
0.01
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
O.01
ฑ0.01
0.01
ฑ0.01
O.01
ฑ0.01
0.02
ฑ0.01
O.01
ฑ0.01
0.01
ฑ0.01
0.41
1.09
3.25
0.03
0.01
0.21
0.12
3.41
0.40
0.14
0.05
0.45
0.25
0.01
O.01
0.01
O.01
0.02
0.01
0.01
O.01
0.01
0.01
0.01
O.01
0.01
O.01
0.01
0.04
0.01
0.01
0.01
O.01
0.01
= a Cancer URE or Noncancer RfC is not available.
a For the annual average concentration of this pollutant in ng/m3, refer to Table 25-5.
25-38
-------
25.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 25-7 and 25-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 25-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the 10
pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million) for the Vermont monitoring sites, as calculated from
the annual averages provided in Table 25-6. Table 25-8 presents similar information, but
identifies the 10 pollutants with the highest noncancer hazard approximations (HQ), also
calculated from annual averages provided in Table 25-6.
The pollutants listed in Tables 25-7 and 25-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 25.3, UNVT sampled for VOCs, PAHs, metals (PMio), and hexavalent chromium;
BURVT and RUVT sampled for VOCs only. In addition, the cancer risk and noncancer hazard
approximations are limited to those pollutants with enough data to meet the criteria for annual
averages to be calculated. A more in-depth discussion of this analysis is provided in
Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this analysis
may help policy-makers prioritize their air monitoring activities.
25-39
-------
Table 25-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Vermont Monitoring Sites
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Burlington, Vermont (Chittenden County) - BURVT
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Dichloromethane
Naphthalene
POM, Group 2b
POM, Group 6
POM, Group la
117.39
57.01
42.71
30.61
12.99
7.10
6.54
1.69
0.20
0.12
Benzene
Formaldehyde
1,3 -Butadiene
Hexavalent Chromium, PM
POM, Group 3
Arsenic, PM
Naphthalene
POM, Group 2b
POM, Group 5a
Ethylbenzene
9.16E-04
7.41E-04
3.90E-04
2.57E-04
2.46E-04
2.44E-04
2.22E-04
1.49E-04
1.24E-04
1.07E-04
Benzene
Carbon Tetrachloride
1,3 -Butadiene
Acrylonitrile
ฃ>-Dichlorobenzene
Ethylbenzene
1 ,2-Dichloroethane
1 , 1 ,2,2-Tetrachloroethane
Hexachloro- 1 , 3 -butadiene
Tetrachloroethylene
6.08
3.52
2.98
1.60
0.77
0.75
0.47
0.41
0.41
0.03
Underbill, Vermont (Chittenden County) - UNVT
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Dichloromethane
Naphthalene
POM, Group 2b
POM, Group 6
POM, Group la
117.39
57.01
42.71
30.61
12.99
7.10
6.54
1.69
0.20
0.12
Benzene
Formaldehyde
1,3 -Butadiene
Hexavalent Chromium, PM
POM, Group 3
Arsenic, PM
Naphthalene
POM, Group 2b
POM, Group 5a
Ethylbenzene
9.16E-04
7.41E-04
3.90E-04
2.57E-04
2.46E-04
2.44E-04
2.22E-04
1.49E-04
1.24E-04
1.07E-04
Carbon Tetrachloride
Benzene
Arsenic
Naphthalene
Acrylonitrile
1 ,2-Dichloroethane
Nickel
1,3 -Butadiene
Hexachloro- 1 , 3 -butadiene
Cadmium
3.41
3.25
1.09
0.45
0.41
0.40
0.25
0.21
0.14
0.12
to
v\
Jฑ
o
-------
Table 25-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Vermont Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Rutland, Vermont (Rutland County) - RUVT
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
POM, Group 2b
Dichloromethane
POM, Group 6
POM, Group la
54.68
24.42
20.01
14.97
6.47
3.14
0.93
0.47
0.12
0.06
Benzene
Formaldehyde
1,3 -Butadiene
POM, Group 3
Hexavalent Chromium, PM
Naphthalene
POM, Group 2b
POM, Group 5a
Ethylbenzene
Acetaldehyde
4.26E-04
3.17E-04
1.94E-04
1.38E-04
1.24E-04
1.07E-04
8.17E-05
6.57E-05
5.00E-05
3.29E-05
Benzene
Carbon Tetrachloride
1,3 -Butadiene
Ethylbenzene
1 ,2-Dichloroethane
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
6.94
3.65
2.80
0.76
0.29
0.03
0.01
0.00
to
-k
-------
Table 25-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Vermont Monitoring Sites
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations (Site-
Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Burlington, Vermont (Chittenden County) - BURVT
Toluene
Xylenes
Benzene
Methanol
Formaldehyde
Ethylbenzene
Hexane
Hydrochloric acid
Acetaldehyde
1,3 -Butadiene
221.14
170.08
117.39
88.67
57.01
42.71
41.71
41.61
30.61
12.99
Acrolein
Manganese, PM
Chlorine
1,3 -Butadiene
Formaldehyde
Benzene
Arsenic, PM
Acetaldehyde
Cyanide Compounds, gas
Naphthalene
552,694.88
67,632.70
13,450.30
6,493.30
5,817.27
3,912.93
3,782.88
3,400.90
2,550.52
2,180.85
1,3 -Butadiene
Benzene
Acrylonitrile
Carbon Tetrachloride
Tetrachloroethylene
Trichloroethylene
Chloroform
Ethylbenzene
Hexachloro- 1 , 3 -butadiene
ฃ>-Dichlorobenzene
0.05
0.03
0.01
0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
Underbill, Vermont (Chittenden County) - UNVT
Toluene
Xylenes
Benzene
Methanol
Formaldehyde
Ethylbenzene
Hexane
Hydrochloric acid
Acetaldehyde
1,3 -Butadiene
221.14
170.08
117.39
88.67
57.01
42.71
41.71
41.61
30.61
12.99
Acrolein
Manganese, PM
Chlorine
1,3 -Butadiene
Formaldehyde
Benzene
Arsenic, PM
Acetaldehyde
Cyanide Compounds, gas
Naphthalene
552,694.88
67,632.70
13,450.30
6,493.30
5,817.27
3,912.93
3,782.88
3,400.90
2,550.52
2,180.85
Manganese
Arsenic
Benzene
Lead
Cadmium
Nickel
Carbon Tetrachloride
Naphthalene
1,3 -Butadiene
Acrylonitrile
0.04
0.02
0.01
0.01
0.01
0.01
0.01
<0.01
<0.01
<0.01
to
v\
Jฑ
to
-------
Table 25-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Vermont Monitoring Sites (Continued)
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Rutland, Vermont (Rutland County) - RUVT
Toluene
Xylenes
Benzene
Methanol
Formaldehyde
Ethylbenzene
Hexane
Acetaldehyde
1,3 -Butadiene
Styrene
121.10
77.74
54.68
37.29
24.42
20.01
17.83
14.97
6.47
5.25
Acrolein
1,3 -Butadiene
Formaldehyde
Cyanide Compounds, gas
Benzene
Acetaldehyde
Naphthalene
Xylenes
Arsenic, PM
Lead, PM
74,401.74
3,234.62
2,492.15
2,311.36
1,822.62
1,663.70
1,045.42
777.44
462.98
399.93
1,3 -Butadiene
Benzene
Carbon Tetrachloride
Tetrachloroethylene
Trichloroethylene
Chloroform
Ethylbenzene
1 ,2-Dichloroethane
Vinyl Chloride
0.05
0.03
0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
to
-------
Observations from Table 25-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Chittenden and Rutland Counties, although the emissions in
Chittenden County were nearly twice those in Rutland County.
Benzene, formaldehyde, and 1.3-butadiene are the pollutants with the highest
toxi city-weighted emissions (of the pollutants with cancer UREs) for both counties.
Six of the highest emitted pollutants also have the highest toxi city-weighted
emissions for Chittenden County while seven of the highest emitted pollutants also
have the highest toxicity-weighted emissions for Rutland County.
Benzene and carbon tetrachloride have the highest cancer risk approximations for all
three sites. Benzene topped both emissions-based lists for both counties, while carbon
tetrachloride appeared on neither emissions-based list for either county.
1,3-Butadiene also appears on all three lists for each site. Ethylbenzene appears on all
three lists for BURVT and RUVT but is not a pollutant of interest for UNVT.
Naphthalene also appears on all three lists for UNVT.
Arsenic has the third highest cancer risk approximation and ranks sixth for toxicity-
weighted emissions, but is not one of the highest emitted.
Benzo(a)pyrene is part of POM, Group 5a and is one of UNVT's pollutants of
interest. POM, Group 5a has the ninth highest toxicity-weighted emissions but is not
among the highest emitted in Chittenden County.
POM, Group 2b ranks eighth for both quantity emitted and its toxicity-weighted
emissions in Chittenden County. POM, Group 2b includes several PAHs sampled for
at UNVT including acenaphthylene, fluoranthene, and perylene. None of the PAHs
included in POM, Group 2b failed screens for UNVT. POM, Groups la, 3, and 6 also
appear in Table 25-7, but only POM, Group 6 includes PAHs sampled for at UNVT
(benzo(a)anthracene, for example), but none of these pollutants failed screens.
Observations from Table 25-8 include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs in Chittenden and Rutland Counties, although the emissions in Chittenden
County were nearly twice those in Rutland County.
Acrolein is the pollutant with the highest toxicity-weighted emissions (of the
pollutants with noncancer RfCs) for both Chittenden and Rutland Counties. Although
acrolein was sampled for at all three sites, this pollutant was excluded from the
pollutants of interest designation, and thus subsequent risk-based screening
evaluations, due to questions about the consistency and reliability of the
measurements, as discussed in Section 3.2.
25-44
-------
Four of the highest emitted pollutants for Chittenden County also have the highest
toxi city-weighted emissions while five of the highest emitted pollutants for Rutland
County also have the highest toxicity-weighted emissions.
Although very low, 1,3-butadiene and benzene have the highest noncancer hazard
approximations for BURVT and RUVT. Benzene and 1,3-butadiene appear on both
emissions-based lists.
Although very low, manganese and arsenic have the highest noncancer hazard
approximations for UNVT. While these pollutants rank second and seventh among
the toxicity-weighted emissions for Chittenden County, respectively, neither pollutant
appears among the highest emitted.
25.6 Summary of the 2011 Monitoring Data for the Vermont Monitoring Sites
Results from several of the data treatments described in this section include the
following:
ปซป A total of 11 pollutants failed screens for BURVT; seven pollutants failed screens for
RUVT; and 13 pollutants failed screens for UNVT.
ปซป None of the annual average concentrations of the pollutants of interest for the
Vermont monitoring sites were greater than 1 jug/m3.
ปซป The annual average concentrations for several of UNVT's pollutants of interest were
the lowest annual averages among allNMP sites sampling those pollutants.
25-45
-------
26.0 Site in Virginia
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Virginia, and integrates these concentrations with
emissions, meteorological, and risk information. Data generated by sources other than ERG are
not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
26.1 Site Characterization
This section characterizes the Virginia monitoring site by providing geographical and
physical information about the location of the site and the surrounding area. This information is
provided to give the reader insight regarding factors that may influence the air quality near the
site and assist in the interpretation of the ambient monitoring measurements.
The RIVA monitoring site is located just outside the Richmond, Virginia city limits.
Figure 26-1 is a composite satellite image retrieved from ArcGIS Explorer showing the
monitoring site in its urban location. Figure 26-2 identifies nearby point source emissions
locations by source category, as reported in the 2008 NEI for point sources. Note that only
sources within 10 miles of the site are included in the facility counts provided in Figure 26-2. A
10-mile boundary was chosen to give the reader an indication of which emissions sources and
emissions source categories could potentially have a direct effect on the air quality at the
monitoring site. Further, this boundary provides both the proximity of emissions sources to the
monitoring site as well as the quantity of such sources within a given distance of the site. Sources
outside the 10-mile radius are still visible on the map, but have been grayed out in order to show
emissions sources just outside the boundary. Table 26-1 provides supplemental geographical
information such as land use, location setting, and locational coordinates.
26-1
-------
Figure 26-1. Richmond, Virginia (RIVA) Monitoring Site
to
ON
to
-------
Figure 26-2. NEI Point Sources Located Within 10 Miles of RIVA
Legend
RIVA NATTS site
7r3Q'fl"W 77c25'
-------
Table 26-1. Geographical Information for the Virginia Monitoring Site
Site
Code
RIVA
AQS Code
51-087-0014
Location
Richmond
County
Henrico
Micro- or
Metropolitan
Statistical Area
Richmond, VA
MSA
Latitude
and
Longitude
37.55655,
-77.400411
Land Use
Residential
Location
Setting
Suburban
Additional Ambient Monitoring Information1
TSP Metals, SO2, NOy, NO, NO2, NOX, PAMS,
NMOCs, VOCs, Carbonyl compounds, O3,
Meteorological parameters, PM10, PM10 Metals,
PM Coarse, PM2 5, and PM2 5 Speciation, CO,
Tetrahydrofuran.
BOLD ITALICS = EPA-designated NATTS Site
to
-k
-------
The RIVA monitoring site is located just northeast of the capital city of Richmond, in
east-central Virginia. The site is located at the MathScience Innovation Center in a residential
area less than 1/4 mile from 1-64. The 1-64 interchange with Mechanicsville Turnpike (360) is
less than 1/2 mile southwest of the site, as shown in Figure 26-1. Beyond the residential areas
surrounding the school property are a golf course to the southeast, a high school to the south (on
the southside of 1-64), and commercial areas to the west. As Figure 26-2 shows, RIVA is located
near several point sources, most of which are located to the southeast and south of the site and
within the city of Richmond. The sources closest to RIVA are a fabricated metal products facility
and a heliport at the Medical College of Virginia. The source categories with the greatest number
of emissions sources within 10 miles of RIVA are aircraft operations, which include airports as
well as small runways, heliports, or landing pads; printing and publishing facilities; bulk
terminals and bulk plants; and facilities generating electricity via combustion.
Table 26-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Virginia monitoring site. Table 26-2 includes county-level
population and vehicle registration information. Table 26-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within the monitoring site's residing county. In addition, the population within 10 miles
of the site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding the monitoring site. Table 26-2 also
contains traffic volume information for RIVA. Finally, Table 26-2 presents the county-level
daily VMT for Henrico County.
Table 26-2. Population, Motor Vehicle, and Traffic Information for the Virginia
Monitoring Site
Site
RIVA
Estimated
County
Population1
310,445
County-level
Vehicle
Registration2
354,721
Vehicles per
Person
(Registration:
Population)
1.14
Population
within 10
miles3
476,219
Estimated
10-mile
Vehicle
Ownership
544,138
Annual
Average
Daily
Traffic4
73,000
County-
level Daily
VMT5
8,246,774
Bounty-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Revenue Division of the County of Henrico (Henrico
County, 2012)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2011 data from the Virginia DOT (VA DOT, 2011)
5County-level VMT reflects 2011 data from the Virginia DOT (VA DOT, 2012)
BOLD ITALICS = EPA-designated NATTS Site
26-5
-------
Observations from Table 26-2 include the following:
RIVA's county-level population is in the lower third of the range compared to other
counties with NMP sites while its 10-mile population is in the middle of the range
among NMP sites.
The county-level and 10-mile vehicle ownerships are in the middle of the range
compared to other NMP sites.
The vehicle-per-person ratio is among the higher ratios compared to other NMP sites.
The traffic volume experienced near RIVA is in the middle of the range compared to
other NMP monitoring sites. The traffic volume provided is for the interchange of
US-360 (Mechanicsville Turnpike) and 1-64.
The daily VMT for Henrico County is in the middle of the range compared to other
counties with NMP sites (where VMT data are available).
26.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Virginia on sample days, as well as over the course of the year.
26.2.1 Climate Summary
The city of Richmond is located in east-central Virginia, east of the Blue Ridge
Mountains and west of the Chesapeake Bay. The James River flows through the west, center, and
south parts of town. Richmond has a modified continental climate. Winters tend to be mild, as
the mountains act as a barrier to cold air and the proximity to the Atlantic Ocean prevents
temperatures from plummeting too low. Summers are warm and humid, also due to these
influences. Precipitation is well distributed throughout the year (Bair, 1992).
26.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station is located at Richmond International Airport
(WBAN 13740). Additional information about the Richmond International Airport weather
station, such as the distance between the site and the weather station, is provided in Table 26-3.
These data were used to determine how meteorological conditions on sample days vary from
conditions experienced throughout the year.
26-6
-------
Table 26-3. Average Meteorological Conditions near the Virginia Monitoring Site
Closest NWS Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Richmond, Virginia - RTVA
Richmond
International Airport
13740
(37.51, -77.32)
5.16
miles
118ฐ
(ESE)
Sample
Day
2011
69.8
ฑ4.2
70.6
+ 1.7
60.0
ฑ4.0
60.6
+ 1.7
47.2
ฑ4.8
47.9
+ 1.8
53.6
ฑ3.9
54.1
+ 1.6
66.8
ฑ3.9
66.7
+ 1.4
1016.9
ฑ1.7
1017.0
+ 0.7
6.4
ฑ0.8
6.2
+ 0.3
1 Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
to
-------
Table 26-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 26-3 is the 95 percent
confidence interval for each parameter. As shown in Table 26-3, average meteorological
conditions on sample days were representative of average weather conditions throughout the
year.
26.2.3 Back Trajectory Analysis
Figure 26-3 is the composite back trajectory map for days on which samples were
collected at the RIVA monitoring site in 2011. Included in Figure 26-3 are four back trajectories
per sample day. Figure 26-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 26-3 and 26-4 represents 100 miles.
Observations from Figures 26-3 and Figure 26-4 for RIVA include the following:
Back trajectories originated from a variety of directions near RIVA, although a large
number of them originated to the northwest.
The 24-hour air shed domain for RIVA was similar in size to many other NMP
monitoring sites. The farthest away a trajectory originated was over the Upper
Peninsula of Michigan, or over 700 miles away. However, the average trajectory
length is 242 miles and most back trajectories (87 percent) originated within
400 miles of the site.
The cluster analysis shows that 28 percent of back trajectories originated from the
northwest of RIVA over Michigan, Ohio, and Indiana. Seventeen percent originated
from the southwest to west and includes back trajectories of varying lengths. The
cluster trajectory originating over eastern North Carolina (36 percent) represents back
trajectories originating from the east, southeast, and south, primarily over eastern
North Carolina but also over the offshore waters of Virginia, North Carolina, and
South Carolina. Another 19 percent of back trajectories originated from the north-
northwest, north, and northeast of the site.
26-8
-------
Figure 26-3. 2011 Composite Back Trajectory Map for RIVA
Figure 26-4. Back Trajectory Cluster Map for RIVA
26-9
-------
26.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Richmond International
Airport near RIVA were uploaded into a wind rose software program to produce customized
wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions
using "petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 26-5 presents a map showing the distance between the NWS station and RIVA,
which may be useful for identifying topographical influences that may affect the meteorological
patterns experienced at this location. Figure 26-5 also presents three different wind roses for the
RIVA monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
Observations from Figure 26-5 for RIVA include the following:
The Richmond International weather station is located approximately 5.1 miles
east-southeast of RIVA.
The historical wind rose shows that the most commonly observed wind direction is
north, although winds from the north-northeast, south, south-southwest, and
southwest were also frequently observed. Winds from the southeast quadrant were
observed the least. Calm winds (< 2 knots) were observed for approximately
15 percent of the hourly wind measurements.
The 2011 wind rose resembles the historical wind rose in some ways but exhibits
differences as well. Southerly and south-southwesterly winds were more prominent in
2011, although northerly winds were still frequently observed.
Northerly winds prevailed on sample days near RIVA, although southerly winds still
accounted for greater than 10 percent of the wind observations. A higher percentage
of winds from the northwest quadrant were observed on sample days compared to the
entire year and historically. There were also fewer wind observations from the
southwest quadrant on sample days compared to the entire year and historically.
26-10
-------
Figure 26-5. Wind Roses for the Richmond International Airport Weather Station near
RIVA
Distance between RIVA and NWS Station
2001-2010 Historical Wind Rose
v
:\
2011 Wind Rose
Sample Day Wind Rose
26-11
-------
26.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Virginia monitoring site in
order to allow analysts and readers to focus on a subset of pollutants through the context of risk.
Each pollutant's preprocessed daily measurement was compared to its associated risk screening
value. If the concentration was greater than the risk screening value, then the concentration
"failed the screen." Pollutants of interest are those for which the individual pollutant's total
failed screens contribute to the top 95 percent of the site's total failed screens. In addition, if any
of the NATTS MQO Core Analytes measured by the monitoring site did not meet the pollutant
of interest criteria based on the preliminary risk-based screening, that pollutant was added to the
list of site-specific pollutants of interest. A more in-depth description of the risk-based screening
process is presented in Section 3.2.
Table 26-4 presents the results of the preliminary risk-based screening process for RIVA.
The pollutants that failed at least one screen and contributed to 95 percent of the total failed
screens for the monitoring site are shaded. NATTS MQO Core Analytes are bolded. Thus,
pollutants of interest are shaded and/or bolded. RIVA sampled for PAHs and hexavalent
chromium.
Table 26-4. Risk-Based Screening Results for the Virginia Monitoring Site
Pollutant
Screening
Value
(Hg/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Richmond, Virginia - RIVA
Naphthalene
Acenaphthene
Benzo(a)pyrene
Fluorene
0.029
0.011
0.00057
0.011
Total
54
1
1
1
57
61
61
30
61
213
88.52
1.64
3.33
1.64
26.76
94.74
1.75
1.75
1.75
94.74
96.49
98.25
100.00
Observations from Table 26-4 include the following:
Although four PAHs failed screens for RIVA, naphthalene contributed to roughly
95 percent of the total failed screens, while the other pollutants accounted for a single
failed screen each.
The risk-based screening process identified all four PAHs failing screens as the
pollutants of interest for RIVA. This is because two of the pollutants contribute to the
minimum 95 percent criteria discussed in Section 3.2, but because benzo(a)pyrene
and fluorene contributed equally to the number of failed screens as acenaphthene,
26-12
-------
these pollutants were also designated as pollutants of interest. Hexavalent chromium
was also added to the pollutants of interest for RIVA because it is a NATTS MQO
Core Analyte, even though it did not fail any screens. This pollutant is not shown in
Table 26-4 but is shown in subsequent tables in the sections that follow.
26.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Virginia monitoring site. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutants of interest for RIVA, where the data meet the applicable criteria. Concentration
averages for select pollutants are also presented graphically to illustrate how the site's
concentrations compare to the program-level averages, as presented in Section 4.1. In addition,
concentration averages for select pollutants are presented from previous years of sampling in
order to characterize concentration trends at the site. Additional site-specific statistical
summaries for RIVA are provided in Appendices M and O.
26.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for RIVA, as described in Section 3.1. The quarterly average of a particular pollutant is simply
the average concentration of the preprocessed daily measurements over a given calendar quarter.
Quarterly average concentrations include the substitution of zeros for all non-detects. A site must
have a minimum of 75 percent valid samples of the total number of samples possible within a
given quarter for a quarterly average to be calculated. An annual average includes all measured
detections and substituted zeros for non-detects for the entire year of sampling. Annual averages
were calculated for pollutants where three valid quarterly averages could be calculated and
where method completeness was greater than or equal to 85 percent, as presented in Section 2.4.
Quarterly and annual average concentrations for the Virginia monitoring site are presented in
Table 26-5, where applicable. Note that if a pollutant was not detected in a given calendar
quarter, the quarterly average simply reflects "0" because only zeros substituted for non-detects
were factored into the quarterly average concentration.
26-13
-------
Table 26-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the Virginia Monitoring Site
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Richmond, Virginia - RJVA
Acenaphthene
Benzo(a)pyrene
Fluorene
Hexavalent Chromium
Naphthalene
61/61
30/61
61/61
48/61
61/61
1.17
ฑ0.21
0.12
ฑ0.07
2.18
ฑ0.34
0.01
ฑ<0.01
72.80
ฑ 20.97
4.53
ฑ1.59
0.01
ฑ0.01
4.83
ฑ1.57
0.01
ฑ<0.01
76.51
ฑ 22.49
4.66
ฑ1.14
0.08
ฑ0.15
4.92
ฑ1.11
0.02
ฑ0.01
70.33
ฑ 15.69
2.05
ฑ0.79
0.10
ฑ0.06
2.69
ฑ0.66
0.01
ฑ<0.01
93.27
ฑ 26.43
3.13
ฑ0.64
0.08
ฑ0.04
3.68
ฑ0.58
0.01
ฑ<0.01
78.10
ฑ 10.38
Observations for RIVA from Table 26-5 include the following:
The annual average concentration of naphthalene is significantly higher than the
annual average concentrations of the remaining pollutants of interest.
The quarterly averages of naphthalene have a relatively high-level of variability
associated with them, as indicated by the confidence intervals. The maximum
concentration measured at RIVA was measured on May 9, 2011 (175 ng/m3),
although 17 concentrations greater than or equal to 100 ng/m3 were measured at this
site. Six of these were measured during the fourth quarter of 2011, while the other
quarters have three or four each.
The quarterly averages of acenaphthene and fluorene are higher in the warmer months
of the year and lower in the colder months of the year. The maximum concentrations
of both of these pollutants were measured on June 8, 2011. Of the 26 acenaphthene
concentrations greater than 3 ng/m3, 11 were measured in the second quarter of 2011
and 12 were measured during the third quarter of 2011. Conversely, all but two of the
11 concentrations less than 1 ng/m3 were measured in the first or fourth quarters of
2011. A similar pattern is shown in the concentrations of fluorene.
The maximum benzo(a)pyrene concentration was measured at RIVA on
August 16, 2011 (1.14 ng/m3) and is one of only seven concentrations greater than
1 ng/m3 for this PAH measured across the program. The second highest concentration
of this pollutant measured at RIVA was half as high (0.515 ng/m3) and was measured
in March. Aside from the August 16th measurement, concentrations of
benzo(a)pyrene tended to be higher during the colder months of the year. Of the
30 measured detections of this pollutant, 12 were measured during the first quarter,
three were measured in the second, five were measured in the third, and 10 were
measured in the fourth. Conversely, of the 31 non-detects, three were measured
during the first quarter, 12 were measured in the second, 11 were measured in the
third, and five were measured in the fourth.
26-14
-------
Hexavalent chromium concentrations ranged from 0.0011 ng/m3 to 0.0466 ng/m3,
with the five highest concentrations all measured during the third quarter of 2011.
26.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for benzo(a)pyrene,
hexavalent chromium, and naphthalene were created for RIVA. Figures 26-6 through 26-8
overlay the site's minimum, annual average, and maximum concentrations onto the program-
level minimum, first quartile, median, average, third quartile, and maximum concentrations, as
described in Section 3.5.3.
Figure 26-6. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
0.75 1 1.25
Concentration (ng/m3)
Program
Site:
: 1st Quartile
Site Average
o
2nd Quartile 3rd Quartile 4th Quartile Ave
Site Minimum/Maximum
'rage
Figure 26-7. Program vs. Site-Specific Average Hexavalent Chromium Concentration
0.15
Concentration (ng/m3)
Program: 1st Quartile 2nd Quartile 3rd Quartile 4th Quartile Average
Site: Site Average Site Minimum/Maximum
26-15
-------
Figure 26-8. Program vs. Site-Specific Average Naphthalene Concentration
F.lvA
Program Max Concentration = 779 ng/m3
50
100
150
200 150 300
Concentration {ng/m3)
= 50
450
555
Program
Site:
: IstQuartile
Site Average
O
2ndQuartile SrdQuartile 4thQuartile AVE
Site Minimum/Maximum
rage
Observations from Figures 26-6 through 26-8 include the following:
Figure 26-6 is the box plot for benzo(a)pyrene. Note that the first quartile for this
pollutant is zero and is not visible on this box plot. This box plot shows that the
annual average concentration for RIVA is just less than the program-level average
concentration. Figure 26-6 also shows that the maximum concentration measured
at RIVA is less than the maximum concentration measured across the program.
Half of the measurements of benzo(a)pyrene were non-detects.
Figure 26-7 is the box plot for hexavalent chromium. Figure 26-7 shows that the
annual average concentration of hexavalent chromium for RIVA is less than both
the program-level average and median concentrations. This site has one of the
lowest annual average concentrations of hexavalent chromium among NMP sites
sampling this pollutant. The maximum concentration measured at RIVA is
considerably less than the maximum concentration measured across the program.
Several non-detects of hexavalent chromium were measured at RIVA.
Figure 26-8 is the box plot for naphthalene. Note that the program-level
maximum concentration (799 ng/m3) is not shown directly on the box plot
because the scale of the box plot would be too large to readily observe data points
at the lower end of the concentration range. Thus, the scale has been reduced to
500 ng/m3. Figure 26-8 shows that the annual average concentration of
naphthalene for RIVA is just less than the program-level average concentration.
The maximum naphthalene concentration measured at RIVA is considerably less
than the program-level maximum concentration. There were no non-detects of
naphthalene measured at RIVA or across the program.
26.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. RIVA did not begin sampling PAHs or hexavalent chromium under the NMP until
October 2008; therefore, the trends analysis was not conducted.
26-16
-------
26.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
RIVA monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations regarding
the various toxicity factors, time frames, and calculations associated with these risk-based
screenings.
26.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Virginia monitoring site to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
26.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for RIVA and where annual average concentrations could
be calculated, risk was examined by calculating cancer risk and noncancer hazard
approximations. These approximations can be used as risk estimates for cancer and noncancer
effects attributable to the pollutants of interest. Although the use of these approximations is
limited, they may help identify where policy-makers may want to shift or confirm their air-
monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer risk and
noncancer hazard approximations are calculated and what limitations are associated with them.
Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer hazard
approximations are presented in Table 26-6, where applicable. Cancer risk approximations are
presented as probabilities while the noncancer hazard approximations are ratios and thus, unitless
values.
26-17
-------
Table 26-6. Risk Approximations for the Virginia Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Richmond, Virginia - RJVA
Acenaphthene
Benzo(a)pyrene
Fluorene
Hexavalent Chromium
Naphthalene
0.000088
0.00176
0.000088
0.012
0.000034
0.0001
0.003
61/61
30/61
61/61
48/61
61/61
3.13
ฑ0.64
0.08
ฑ0.04
3.68
ฑ0.58
0.01
ฑ0.01
78.10
ฑ 10.38
0.28
0.14
0.32
0.15
2.66
0.01
0.03
= a Cancer URE or Noncancer RfC is not available
Observations for RIVA from Table 26-6 include the following:
The pollutant with the highest annual average concentration for RIVA is naphthalene,
followed by fluorene and acenaphthene, although the annual average for naphthalene
is significantly higher than the other annual average concentrations.
The cancer risk approximation for naphthalene is 2.66 in-a-million. The cancer risk
approximations for the remaining pollutants of interest are less than 1.0 in-a-million.
Only two of the pollutants of interest for RIVA have noncancer toxicity factors. The
noncancer hazard approximations for hexavalent chromium and naphthalene are
considerably less than 1.0, indicating that no adverse health effects are expected from
these individual pollutants.
26.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 26-7 and 26-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 26-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 26-6. Table 26-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 26-6.
26-18
-------
Table 26-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Virginia Monitoring Site
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based
on Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Richmond, Virginia (Henrico County) - RTVA
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
Dichloromethane
POM, Group 2b
Tetrachloroethylene
POM, Group la
115.26
90.51
64.92
60.31
19.67
9.77
2.81
1.91
0.38
0.19
Formaldehyde
Benzene
1,3 -Butadiene
Naphthalene
POM, Group 3
Hexavalent Chromium, PM
POM, Group 2b
Ethylbenzene
Acetaldehyde
Arsenic, PM
1.18E-03
8.99E-04
5.90E-04
3.32E-04
2.60E-04
2.50E-04
1.68E-04
1.62E-04
1.33E-04
6.94E-05
Naphthalene
Fluorene
Acenaphthene
Hexavalent Chromium
Benzo(a)pyrene
2.66
0.32
0.28
0.15
0.14
to
-------
Table 26-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Virginia Monitoring Site
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations (Site-
Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Richmond, Virginia (Henrico County) - RTVA
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Hexane
Ethylbenzene
Acetaldehyde
Ethylene glycol
1,3 -Butadiene
752.59
248.81
175.23
115.26
90.51
75.32
64.92
60.31
21.10
19.67
Acrolein
1,3 -Butadiene
Formaldehyde
Acetaldehyde
Benzene
Naphthalene
Xylenes
Arsenic, PM
Lead, PM
Propionaldehyde
216,262.42
9,835.00
9,235.99
6,700.91
3,842.01
3,257.58
2,488.08
1,076.66
792.69
689.88
Naphthalene 0.03
Hexavalent Chromium O.01
to
to
o
-------
The pollutants listed in Tables 26-7 and 26-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 26.3, RIVA sampled for PAHs and hexavalent chromium. In addition, the cancer risk
and noncancer hazard approximations are limited to those pollutants with enough data to meet
the criteria for annual averages to be calculated. A more in-depth discussion of this analysis is
provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this
analysis may help policy-makers prioritize their air monitoring activities.
Observations from Table 26-7 include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in Henrico County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
cancer UREs) are formaldehyde, benzene, and 1,3-butadiene.
Seven of the highest emitted pollutants also have the highest toxicity-weighted
emissions for Henrico County.
Naphthalene, which is the pollutant with the highest cancer risk approximation for
RIVA, has the sixth highest emissions and the fourth highest toxicity-weighted
emissions for Henrico County.
POM, Group 2b is the eighth highest emitted "pollutant" in Henrico County and ranks
seventh for toxicity-weighted emissions. POM, Group 2b includes several PAHs
sampled for at RIVA including acenaphthene and fluorene.
Hexavalent chromium does not appear among the highest emitted pollutants, but
ranks sixth for the toxicity-weighted emissions.
Observations from Table 26-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in Henrico County.
The pollutants with the highest toxicity-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, 1,3-butadiene, and formaldehyde.
Five of the highest emitted pollutants in Henrico County also have the highest
toxicity-weighted emissions.
26-21
-------
Naphthalene has the sixth highest toxicity-weighted emissions for Henrico County
but is not among the highest emitted pollutants with a noncancer toxicity factor in
Henrico County.
Hexavalent chromium appears on neither emissions-based list.
26.6 Summary of the 2011 Monitoring Data for RIVA
Results from several of the data treatments described in this section include the
following:
ปซป Although four pollutants failed screens for RIVA, naphthalene failed the majority of
screens.
ปซป The annual average concentration of naphthalene was significantly higher than the
annual average concentrations of the other pollutants of interest.
ปซป Benzo(a)pyrene concentrations appear higher during the colder months of the year
while concentrations of acenaphthene andfluorene appear higher during the warmer
months of the year.
26-22
-------
27.0 Site in Washington
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Washington, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
27.1 Site Characterization
This section characterizes the monitoring site by providing geographical and physical
information about the location of the site and the surrounding area. This information is provided
to give the reader insight regarding factors that may influence the air quality near the site and
assist in the interpretation of the ambient monitoring measurements.
The NATTS site in Washington is located in Seattle. Figure 27-1 is a composite satellite
image retrieved from ArcGIS Explorer showing the monitoring site in its urban location.
Figure 27-2 identifies nearby point source emissions locations by source category, as reported in
the 2008 NEI for point sources. Note that only sources within 10 miles of the site are included in
the facility counts provided in Figure 27-2. A 10-mile boundary was chosen to give the reader an
indication of which emissions sources and emissions source categories could potentially have a
direct effect on the air quality at the monitoring site. Further, this boundary provides both the
proximity of emissions sources to the monitoring site as well as the quantity of such sources
within a given distance of the site. Sources outside the 10-mile radius are still visible on the map,
but have been grayed out in order to show emissions sources just outside the boundary.
Table 27-1 provides supplemental geographical information such as land use, location setting,
and locational coordinates.
27-1
-------
Figure 27-1. Seattle, Washington (SEWA) Monitoring Site
to
-------
Figure 27-2. NEI Point Sources Located Within 10 Miles of SEWA
122-4OT-W 122-35-0-W 122'30irYV 122'25'0-W
122'15'CTW 122'10'0"W
122-3CTO-W I22-2S-0-W 122'20'0-W
Legend
12T1DWV I22'5'0"W 122"0'Crw
Note: Due- to facility density and collocation the total facilities
displayed may not represent all facilities within the area of interest.
@ SEWA NATTS site 10 mile radius | | County boundary
Source Category Group (No. of Facilities) v Glass Manufacturing (1)
"i< Aerospace/Aircraft Manufacturing (2)
ซ> Air-conditioning/Refrigeration (1)
+1 Aircraft Operations (25)
H Automobile/Truck Manufacturing (1)
IB Bakery (2)
Brick Manufacturing & Structural Clay (1)
^ Institutional - school (1)
? Miscellaneous Commercial/Industrial (2)
7 Portland Cement Manufacturing (2)
A Ship Building and Repairing (1)
V Steel Mill (1)
' Wastewater Treatment (1)
27-3
-------
Table 27-1. Geographical Information for the Washington Monitoring Site
Site
Code
SEWA
AQS Code
53-033-0080
Location
Seattle
County
King
Micro- or
Metropolitan
Statistical Area
Seattle-Tacoma-
Bellevue, WA
MSA (Seattle Div)
Latitude
and
Longitude
47.568333,
-122.308056
Land Use
Industrial
Location
Setting
Suburban
Additional Ambient Monitoring Information1
Haze, CO, SO2, NOy, NO, O3, Meteorological
parameters, PM Coarse, PM10, Black Carbon, PM2 5,
PM2 5 Speciation.
BOLD ITALICS = EPA-designated NATTS Site
to
-k
-------
The SEWA monitoring site is located in Seattle, at the southeast corner of the Beacon
Hill Reservoir. The reservoir and the Jefferson Park Golf Course to the east are separated by
Beacon Avenue. A middle school and a hospital can be seen to the south of the site in the
bottom-most portion of Figure 27-1. The site is surrounded by residential neighborhoods to the
west, north, and east. Interstate-5, which runs north-south through Seattle, is less than 1 mile to
the west and intersects with 1-90 a couple of miles to the north of the site. The area to the west of
1-5 is industrial while the area to the east is primarily residential. Although the emissions sources
within 10 miles of the site are involved in a variety of industries, the aircraft operations source
category, which includes airports, as well as small runways, heliports, or landing pads, has the
greatest number of sources. The point source located closest to SEWA is a bakery.
Table 27-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Washington monitoring site. Table 27-2 includes county-level
population and vehicle registration information. Table 27-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within the monitoring site's residing county. In addition, the population within 10 miles
of the site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding the monitoring site. Table 27-2 also
contains traffic volume information for SEWA. Finally, Table 27-2 presents the county-level
daily VMT for King County.
Table 27-2. Population, Motor Vehicle, and Traffic Information for the Washington
Monitoring Site
Site
SEWA
Estimated
County
Population1
1,969,722
County-level
Vehicle
Registration2
1,783,335
Vehicles per
Person
(Registration:
Population)
0.91
Population
within 10
miles3
983,171
Estimated
10-mile
Vehicle
Ownership
890,137
Annual
Average
Daily
Traffic4
226,000
County-
level Daily
VMT5
23,282,703
County-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Washington Dept of Licensing (WA DOL, 2011)
' 10-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
'AADT reflects 2011 data from the Washington DOT (WA DOT, 2011)
'County-level VMT reflects 2011 data from the Washington DOT (WA DOT, 2011)
BOLD ITALICS = EPA-designated NATTS Site
27-5
-------
Observations from Table 27-2 include the following:
King County has the sixth highest county-level population among counties with NMP
sites. The 10-mile population estimate for SEWA ranks lower but still in the top third
among NMP sites.
The county-level and 10-mile vehicle registration counts for SEWA mimick the
rankings of the county-level and 10-mile populations.
The vehicle-per-person ratio for SEWA is in the middle of the range compared to
other NMP sites.
The traffic volume experienced near SEWA is the third highest compared to other
NMP monitoring sites. The traffic estimate provided is for 1-5 near Spokane Street.
The daily VMT for King County is in the top third compared to other counties with
NMP sites (where VMT data were available).
27.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Washington on sample days, as well as over the course of the year.
27.2.1 Climate Summary
The city of Seattle is located between Puget Sound and Lake Washington. The entire
urban area is situated between the Olympic Mountains to the west and the Cascades to the east.
The area experiences a mild climate as the mountains moderate storm systems that move into the
Pacific Northwest and both the mountains and the Sound shield the city from temperature
extremes. Although the city is known for its cloudy, rainy conditions, actual precipitation totals
tend to be lower compared to many locations east of the Rocky Mountains. The winter months
are the wettest and the summer months the driest. Prevailing winds are out of the southwest
(Bair, 1992).
27-6
-------
27.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest SEWA were retrieved
for 2011 (NCDC, 2011). The closest weather station to SEWA is located at Boeing Field/King
County International Airport (WBAN 24234). Additional information about this weather station,
such as the distance between the site and the weather station, is provided in Table 27-3. These
data were used to determine how meteorological conditions on sample days vary from conditions
experienced throughout the year.
Table 27-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 27-3 is the 95 percent
confidence interval for each parameter. As shown in Table 27-3, average meteorological
conditions on sample days appear slightly cooler and drier than average weather conditions
experienced throughout the year, although the differences are not statistically significant.
27.2.3 Back Trajectory Analysis
Figure 27-3 is the composite back trajectory map for days on which samples were
collected at the SEWA monitoring site in 2011. Included in Figure 27-3 are four back trajectories
per sample day. Figure 27-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 27-3 and 27-4 represents 100 miles.
27-7
-------
to
-------
Figure 27-3. 2011 Composite Back Trajectory Map for SEWA
Figure 27-4. Back Trajectory Cluster Map for SEWA
27-9
-------
Observations from Figures 27-3 and 27-4 for SEWA include the following:
Back trajectories originated from a variety of directions from SEWA, although less
frequently from the northeast quadrant.
The 24-hour air shed domain for SEWA is somewhat smaller in size than many other
NMP sites. Although the longest trajectory originated 800 miles away over the
Pacific Ocean, the average trajectory length was less than 200 miles long and
86 percent of trajectories originated within 300 miles of the site.
The cluster analysis shows that 35 percent of back trajectories originated over the
Pacific Ocean, but are represented by three cluster trajectories. One represents back
trajectories originating well offshore (4 percent), one represents back trajectories
originating over the offshore waters of southwest Washington and Oregon
(17 percent), and one represents back trajectories originating south and west of
Vancouver Island (14 percent). Twenty percent of back trajectories originated over
northwest Washington and British Columbia, Canada, and generally less than
200 miles from the site. Another 16 percent of back trajectories originated over
central Washington, 18 percent originated over south-central Washington and north-
central Oregon, and 11 percent originated to the south of SEWA over western Oregon
and northern California.
27.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Boeing Field/King County
International Airport were uploaded into a wind rose software program to produce customized
wind roses, as described in Section 3.5.2.2. A wind rose shows the frequency of wind directions
using "petals" positioned around a 16-point compass, and uses different colors to represent wind
speeds.
Figure 27-5 presents a map showing the distance between the NWS station and SEWA,
which may be useful for identifying topographical influences that can affect the meteorological
patterns experienced at this location. Figure 27-5 also presents three different wind roses for the
SEWA monitoring site. First, a historical wind rose representing 2001 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind data for all of 2011 is presented. Next, a
wind rose representing wind data for days on which samples were collected in 2011 is presented.
These can be used to identify the predominant wind speed and direction for 2011 and determine
if wind observations on sample days were representative of conditions experienced over the
entire year and historically.
27-10
-------
Figure 27-5. Wind Roses for the Boeing Field/King County International Airport Weather
Station near SEWA
Distance between SEWA and NWS Station
2001-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
27-11
-------
Observations from Figure 27-5 for SEWA include the following:
The Boeing Field/King County Airport weather station is located approximately
2.7 miles south of SEWA.
The historical wind rose shows that southeasterly, south-southeasterly, and southerly
winds were frequently observed, accounting for nearly 40 percent of observations.
Calm winds (< 2 knots) accounted for 24 percent of wind observations near SEWA.
The wind patterns shown on the 2011 wind rose are similar to the historical wind
patterns, although the percentage of calm winds is slightly higher (nearly 28 percent)
in 2011.
The wind patterns shown on the sample day wind rose resemble the historical and
2011 wind patterns, indicating that conditions on sample days were representative of
those experienced over the entire year and historically.
27.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Washington monitoring site
in order to allow analysts and readers to focus on a subset of pollutants through the context of
risk. Each pollutant's preprocessed daily measurement was compared to its associated risk
screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by the monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 27-4 presents the results of the preliminary risk-based screening process for
SEWA. The pollutants that failed at least one screen and contributed to 95 percent of the total
failed screens are shaded. NATTS MQO Core Analytes are bolded. Thus, pollutants of interest
are shaded and/or bolded. SEWA sampled for PMi0 metals, VOCs, PAHs, carbonyl compounds,
and hexavalent chromium.
27-12
-------
Table 27-4. Risk-Based Screening Results for the Washington Monitoring Site
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Seattle, Washington - SEWA
Benzene
Carbon Tetrachloride
Formaldehyde
Acet aldehyde
Arsenic (PM10)
1,3-Butadiene
Naphthalene
Manganese (PM10)
1 ,2-Dichloroethane
Nickel (PM10)
Ethylbenzene
Dichloromethane
Hexavalent Chromium
Benzo(a)pyrene
Cadmium (PM10)
Acenaphthene
Acrylonitrile
1 , 1 ,2,2-Tetrachloroethane
0.13
0.17
0.077
0.45
0.00023
0.03
0.029
0.005
0.038
0.0021
0.4
7.7
0.000083
0.00057
0.00056
0.011
0.015
0.017
Total
61
61
60
58
56
52
51
24
17
14
12
5
4
2
2
1
1
1
482
61
61
60
60
61
52
60
61
17
61
61
61
59
25
61
60
1
1
883
100.00
100.00
100.00
96.67
91.80
100.00
85.00
39.34
100.00
22.95
19.67
8.20
6.78
8.00
3.28
1.67
100.00
100.00
54.59
12.66
12.66
12.45
12.03
11.62
10.79
10.58
4.98
3.53
2.90
2.49
1.04
0.83
0.41
0.41
0.21
0.21
0.21
12.66
25.31
37.76
49.79
61.41
72.20
82.78
87.76
91.29
94.19
96.68
97.72
98.55
98.96
99.38
99.59
99.79
100.00
Observations from Table 27-4 for SEWA include the following:
Eighteen pollutants failed at least one screen for SEWA, of which 12 are NATTS
MQO Core Analytes.
The risk-based screening process identified 11 pollutants of interest, of which all but
two are NATTS MQO Core Analytes. Hexavalent chromium, benzo(a)pyrene, and
cadmium were added to SEWA's pollutants of interest because they are NATTS
MQO Core Analytes, even though they did not contribute to 95 percent of the total
failed screens. Six additional pollutants were added to SEWA's pollutants of interest
because they are NATTS MQO Core Analytes, even though they did not fail any
screens (beryllium, chloroform, lead, tetrachloroethylene, trichloroethylene, and vinyl
chloride). These six pollutants are not shown in Table 27-4 but are shown in
subsequent tables in the sections that follow.
Benzene, 1,3-butadiene, carbon tetrachloride, and formaldehyde failed 100 percent of
screens for SEWA. 1,2-Dichloroethane, acrylonitrile, and 1,1,2,2-tetrachloroethane
also failed 100 percent of screens for SEWA, but were detected less frequently.
27-13
-------
27.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Washington monitoring site. Where applicable, the following calculations and data
analyses were performed: Time period-based concentration averages (quarterly and annual) are
provided for the pollutants of interest for the Washington monitoring site, where the data meet
the applicable criteria. Concentration averages for select pollutants are also presented graphically
to illustrate how the site's concentrations compare to the program-level averages, as presented in
Section 4.1. In addition, concentration averages for select pollutants are presented from previous
years of sampling in order to characterize concentration trends at the site. Additional site-specific
statistical summaries for SEWA are provided in Appendices J, L, M, N, and O.
27.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for SEWA, as described in Section 3.1. The quarterly average of a particular pollutant is simply
the average concentration of the preprocessed daily measurements over a given calendar quarter.
Quarterly average concentrations include the substitution of zeros for all non-detects. A site must
have a minimum of 75 percent valid samples of the total number of samples possible within a
given quarter for a quarterly average to be calculated. An annual average includes all measured
detections and substituted zeros for non-detects for the entire year of sampling. Annual averages
were calculated for pollutants where three valid quarterly averages could be calculated and
where method completeness was greater than or equal to 85 percent, as presented in Section 2.4.
Quarterly and annual average concentrations for the Washington monitoring site are presented in
Table 27-5, where applicable. Note that concentrations of the PAHs, metals, and hexavalent
chromium are presented in ng/m3 for ease of viewing. Also note that if a pollutant was not
detected in a given calendar quarter, the quarterly average simply reflects "0" because only zeros
substituted for non-detects were factored into the quarterly average concentration.
27-14
-------
Table 27-5. Quarterly and Annual Average Concentrations of the Pollutants of Interest for
the SEWA Monitoring Site
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(Ug/m3)
2nd
Quarter
Average
(Ug/m3)
3rd
Quarter
Average
(Ug/m3)
4th
Quarter
Average
(Ug/m3)
Annual
Average
(Ug/m3)
Seattle, Washington - SEWA
Acetaldehyde
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
Arsenic (PM10)a
Benzo(a)pyrene a
Bery Ilium (PM10)a
Cadmium (PM10)a
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
60/60
61/61
52/61
61/61
57/61
17/61
61/61
60/60
46/61
5/61
1/61
61/61
25/60
61/61
61/61
59/61
61/61
61/61
60/60
61/61
0.80
ฑ0.23
0.88
ฑ0.27
0.11
ฑ0.06
0.55
ฑ0.04
0.10
ฑ0.01
0
0.30
ฑ0.14
0.77
ฑ0.22
0.14
ฑ0.07
0.01
ฑ0.02
0
0.57
ฑ0.25
0.08
ฑ0.08
0.02
ฑ0.02
0.17
ฑ0.13
0.04
ฑ0.02
2.83
ฑ1.11
7.36
ฑ4.65
82.50
ฑ 42.28
1.19
ฑ0.51
0.80
ฑ0.26
0.56
ฑ0.17
0.04
ฑ0.02
0.65
ฑ0.06
0.14
ฑ0.02
0.04
ฑ0.03
0.20
ฑ0.04
0.77
ฑ0.15
0.03
ฑ0.03
0
0
0.46
ฑ0.17
0.01
ฑ<0.01
<0.01
ฑ0.01
0.07
ฑ0.02
0.02
ฑ0.01
2.20
ฑ0.44
5.57
ฑ3.31
36.18
ฑ8.84
1.97
ฑ1.11
1.17
ฑ0.19
0.42
ฑ0.07
0.06
ฑ0.02
0.66
ฑ0.03
0.14
ฑ0.04
O.01
ฑ0.01
0.28
ฑ0.05
0.99
ฑ0.16
0.08
ฑ0.03
0
0.01
ฑ0.01
0.50
ฑ0.11
0.01
ฑ0.01
O.01
ฑ0.01
0.06
ฑ0.01
0.02
ฑ0.01
2.49
ฑ0.29
9.36
ฑ5.08
65.76
ฑ20.36
3.39
ฑ1.22
0.96
ฑ0.12
0.96
ฑ0.21
0.14
ฑ0.04
0.72
ฑ0.05
0.11
ฑ0.02
0.05
ฑ0.02
0.38
ฑ0.08
0.82
ฑ0.20
0.12
ฑ0.04
0.01
ฑ0.01
0
1.05
ฑ0.26
0.22
ฑ0.17
O.01
ฑ0.01
0.11
ฑ0.03
0.05
ฑ0.02
3.84
ฑ1.14
9.76
ฑ6.85
99.48
ฑ 29.66
1.07
ฑ0.22
0.94
ฑ0.10
0.71
ฑ0.11
0.09
ฑ0.02
0.65
ฑ0.03
0.12
ฑ0.01
0.02
ฑ0.01
0.30
ฑ0.04
0.84
ฑ0.09
0.09
ฑ0.02
0.01
ฑ0.01
0.01
ฑ0.01
0.66
ฑ0.12
0.08
ฑ0.05
0.01
ฑ0.01
0.10
ฑ0.03
0.03
ฑ0.01
2.89
ฑ0.44
8.17
ฑ2.57
72.81
ฑ 14.58
1.90
ฑ0.46
a Average concentrations provided for the pollutants below the blue line are presented in ng/m for
ease of viewing.
27-15
-------
Observations from Table 27-5 include the following:
The annual average concentrations for all of SEWA's pollutants of interest are less
than 1.0 |ig/m3. The pollutants with the highest annual average concentrations by
mass are acetaldehyde (0.94 ฑ 0.10 |ig/m3), formaldehyde (0.84 ฑ 0.09 |ig/m3),
benzene (0.71 ฑ0.11 |ig/m3), and carbon tetrachloride (0.65 ฑ 0.03 |ig/m3).
Even though acetaldehyde and formaldehyde have the highest annual average
concentrations among SEWA's pollutants of interest, these annual averages are the
lowest among other NMP sites sampling carbonyl compounds, similar to previous
years.
Several of the VOCs and PAHs appear to be higher during the colder months of year.
However, the confidence intervals indicate that most of these differences are not
statistically significant and that there is considerable variability in the measurements.
The fourth quarter average concentration of arsenic is greater than the other quarterly
averages. A review of the data shows that of the 14 concentrations greater than
1 ng/m3 measured at SEW A, 10 were measured during the fourth quarter. The
maximum arsenic concentration was measured on December 14, 2011 (2.04 ng/m3).
The maximum concentrations of lead (9.45 ng/m3) and manganese (48.7 ng/m3) were
also measured on this date.
The fourth quarter average concentration of lead is also greater than the other
quarterly averages of lead and both the first and fourth quarter averages have large
confidence intervals associated with them. A review of the data shows that
concentrations of lead range from 1.12 ng/m3 to 9.45 ng/m3, with a median
concentration of 2.47 ng/m3. Of the 10 concentrations greater than 3.50 ng/m3
measured at SEW A, seven were measured during the fourth quarter and three in the
first quarter of 2011.
The quarterly averages of manganese have a high-level of variability in the
measurements, as indicated by the associated confidence intervals. Concentrations of
manganese range from 0.647 ng/m3 to 48.7 ng/m3, with a median concentration of
4.01 ng/m3. Of the 10 concentrations greater than 15 ng/m3 measured at SEW A, two
were measured during the first quarter of 2011, one in the second quarter, three in the
third quarter, and four in the fourth quarter.
The second and third quarter average concentrations of nickel have large confidence
intervals associated with them. A review of the data shows that concentrations of
nickel range from 0.431 ng/m3 to 7.97 ng/m3. The maximum concentration of nickel
was measured on August 7, 2011 and is the maximum nickel concentration measured
among NMP sites sampling this pollutant. Of the 13 nickel concentrations greater
than 5 ng/m3 measured across the program, seven were measured at SEWA. All but
one of the 13 concentrations greater than 3 ng/m3 measured at SEWA were measured
in the second and third quarters of 2011, explaining the relatively large confidence
intervals associated with those quarterly averages.
27-16
-------
The first and fourth quarter average concentrations of naphthalene are greater than the
other quarterly averages and the first quarter average has a large confidence interval
associated with it. A review of the data shows that the maximum concentration of
naphthalene was measured on January 27, 2011 (308 ng/m3) and that two additional
concentrations greater than 200 ng/m3 were measured in November and December.
All but two of the 12 concentrations greater than 100 ng/m3 were measured in either
the first or fourth quarters of 2011. Conversely, all but one of the nine concentrations
less than 30 ng/m3 were measured in the second or third quarter of 2011.
The first and fourth quarter average concentrations of benzo(a)pyrene are greater than
the other quarterly averages, particularly the fourth quarter, and both averages have
relatively large confidence intervals associated with them. A review of the data shows
that the maximum concentration was measured on November 29, 2011 (1.30 ng/m3).
This is one of seven concentrations of benzo(a)pyrene greater than 1 ng/m3 measured
across the program. The next highest concentration measured at SEWA is roughly
half as high (0.764 ng/m3, measured on December 14, 2011). Of the 14
benzo(a)pyrene concentrations greater than 0.1 ng/m3, four were measured in January
and February and 10 were measured in November and December.
No samples were collected at SEWA between June 20, 2011 and July 13, 2011.
However, make-up samples were collected in the latter half of July.
Tables 4-9 through 4-12 present the sites with the 10 highest annual average
concentrations for each of the program-level pollutants of interest. Observations for SEWA from
those tables include the following:
As shown in Table 4-12, SEWA has the highest annual average concentration of
nickel among all sites sampling metals (PMio and TSP) for the second year in a row.
Recall that only nine sites sampled PMio metals; as a result every site sampling PMio
metals appears in Table 4-12 for each metal.
SEWA has the fourth highest concentrations of arsenic and manganese and ranks fifth
highest for hexavalent chromium.
27-17
-------
27.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, box plots for acetaldehyde, arsenic,
benzene, benzo(a)pyrene, 1,3-butadiene, formaldehyde, hexavalent chromium, lead, manganese,
and naphthalene were created for SEWA. Figures 27-6 through 27-15 overlay the site's
minimum, annual average, and maximum concentrations onto the program-level minimum, first
quartile, median, average, third quartile, and maximum concentrations for each pollutant, as
described in Section 3.5.3.
Figure 27-6. Program vs. Site-Specific Average Acetaldehyde Concentration
SEWA
-
0
2 4 6 B 10 12
Concentration (u=ym3)
Program: 1st Quartile 2nd Quartile 3rd Quartile
D D
Site: Site Average Site Minimum/Maximum
o
4th Quartile
Av(
14
;rage
1
Figure 27-7. Program vs. Site-Specific Average Arsenic (PMio) Concentration
m
SEWA
0.5
1 1.5 2 2.5 3 3.5 4 4.5
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
27-18
-------
Figure 27-8. Program vs. Site-Specific Average Benzene Concentration
SE'.'rt
D
L 1
P 1
1
I PrnirramMavrnnrpntratinn = 5^.
I
B ug/m3
1234567891
Concentration (p/m3)
Program:
Site:
IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
D D
Site Average Site Minimum/Maximum
o
Figure 27-9. Program vs. Site-Specific Average Benzo(a)pyrene Concentration
0.75 1 1.15
Concentration (ng/m3)
Program: IstQuartile 2ndQuartile 3rdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 27-10. Program vs. Site-Specific Average 1,3-Butadiene Concentration
I
Program Max Concentration = 9.51 |ig/m3
3.5
1.5
Concentration (jig/mi)
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
27-19
-------
Figure 27-11. Program vs. Site-Specific Average Formaldehyde Concentration
SE'.'rt
D
10
15
Concentration
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 27-12. Program vs. Site-Specific Average Hexavalent Chromium Concentration
SE'.';'i.
0.05
0.1
0.15
Concentration (ng/mi)
3.2
DL25
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 27-13. Program vs. Site-Specific Average Lead (PMi0) Concentration
SE'.'rt
15 20
Concentration (ng/m3)
25
33
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
35
27-20
-------
Figure 27-14. Program vs. Site-Specific Average Manganese (PMi0) Concentration
SE'.'rt
I Program Max CoricEirtratior = 395 ng/m3
100 125
Concentration (ng/mi)
150
17E
200
Program: IstQuartile 2ndQuartile SrdQuartile 4thQuartile Average
Site: Site Average Site Minimum/Maximum
Figure 27-15. Program vs. Site-Specific Average Naphthalene Concentration
SEWA
Program Max Concentration = 779 ng/m3
50
100
150
200 250 300
Concentration (ng/mi)
350
400
450
5M
Program:
Site:
IstQuartile 2ndC
Site Average Site l\
O
Observations from Figures 27-6 through 27-15 include the following:
Figure 27-6 shows that SEWA's annual average acetaldehyde concentration is
considerably less than the program-level average for acetaldehyde and is actually
less than the program-level first quartile (25th percentile). Even the maximum
acetaldehyde concentration measured at SEWA less than the program-level
average concentration. This site has the lowest annual average concentration of
acetaldehyde among NMP sites sampling carbonyl compounds.
Figure 27-7 shows that SEWA's annual average arsenic (PMio) concentration is
greater than the program-level average concentration of arsenic (PMio). The
maximum arsenic concentration measured at SEWA is roughly half the maximum
concentration measured across the program. There were no non-detects of arsenic
measured at SEWA.
Figure 27-8 is the box plot for benzene. Note that the program-level maximum
concentration (23.8 |ig/m3) is not shown directly on the box plot because the scale
of the box plot would be too large to readily observe data points at the lower end
of the concentration range. Thus, the scale has been reduced to 10 |ig/m3.
Figure 27-8 shows that the annual average concentration for SEWA is less than
the program-level average concentration but greater than the program-level
median concentration. The maximum benzene concentration measured at SEWA
is considerably less than the maximum benzene concentration measured across
27-21
-------
the program. There were no non-detects of benzene measured at SEWA or across
the program.
Figure 27-9 is the box plot for benzo(a)pyrene. Note that the first quartile for this
pollutant is zero and is not visible on this box plot. This box plot shows that the
annual average concentration for SEWA is roughly equivalent to the program-
level average concentration. Although the maximum concentration measured at
SEWA is less than the maximum concentration measured across the program, it is
one of the higher measurements. Nearly 60 percent of the benzo(a)pyrene
measurements at SEWA were non-detects.
Figure 27-10 is the box plot for 1,3-butadiene. Similar to the benzene box plot,
the program-level maximum concentration (9.51 |ig/m3) is not shown directly on
the box plot as the scale has been reduced to 3 |ig/m3 in order to allow for the
observation of data points at the lower end of the concentration range. This figure
shows that the annual average concentration for SEWA is less than the program-
level average concentration but greater than the program-level median
concentration. Figure 27-10 also shows that the maximum 1,3-butadiene
concentration measured at SEWA is considerably less than the maximum
concentration measured across the program. A few non-detects of 1,3-butadiene
were measured at SEWA.
Figure 27-11 shows that SEWA's annual average formaldehyde concentration is
less than the program-level first quartile, similar to acetaldehyde. The maximum
formaldehyde concentration measured at SEWA is less than the program-level
median concentration. This site has the lowest annual average concentration of
formaldehyde among NMP sites sampling carbonyl compounds and the second
smallest range of concentrations.
Figure 27-12 shows that the annual average concentration of hexavalent
chromium for SEWA is greater than the program-level average concentration and
the program-level third quartile. The maximum hexavalent chromium
concentration measured at SEWA is less than the maximum hexavalent chromium
concentration measured across the program. Two non-detects of hexavalent
chromium were measured at SEWA.
Figure 27-13 shows that the annual average concentration of lead (PMio) for
SEWA is less than the program-level average but just greater than the program-
level median concentration. The maximum lead concentration measured at SEWA
is considerably less than the maximum lead concentration measured across the
program. There were no non-detects of lead measured at SEWA.
Figure 27-14 is the box plot for manganese. The program-level maximum
concentration (395 ng/m3) is not shown directly on the box plot as the scale has
been reduced to 200 |ig/m3 in order to allow for the observation of data points at
the lower end of the concentration range. This figure shows that the annual
average concentration of manganese (PMio) for SEWA is less than the program-
level average concentration. The maximum manganese concentration measured at
27-22
-------
SEWA is considerably less than the maximum concentration measured across the
program. There were no non-detects of manganese measured at SEWA.
Figure 27-15 is the box plot for naphthalene. The program-level maximum
concentration (779 ng/m3) is not shown directly on the box plot as the scale has
been reduced to 500 |ig/m3 in order to allow for the observation of data points at
the lower end of the concentration range. Figure 27-15 shows that the annual
average concentration of naphthalene for SEWA is less than the program-level
average concentration. The maximum naphthalene concentration measured at
SEWA is less than the program-level maximum concentration. There were no
non-detects of naphthalene measured at SEWA or across the program.
27.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. Sampling for hexavalent chromium at SEWA began in 2005 while sampling for
PMio metals, VOCs, and carbonyl compounds began in 2007; thus, Figures 27-16 through 27-23
present the annual statistical metrics for acetaldehyde, arsenic, benzene, 1,3-butadiene,
formaldehyde, hexavalent chromium, lead, and manganese, respectively. The statistical metrics
presented for assessing trends include the substitution of zeros for non-detects. A trends analysis
was not conducted for the PAHs because sampling for PAHs did not begin at SEWA until 2008.
Observations from Figure 27-16 for acetaldehyde measurements at SEWA include the
following:
The maximum acetaldehyde concentration was measured at SEWA on July 17, 2007
(9.73 |ig/m3). The next highest concentration was considerably less (3.36 |ig/m3,
measured in September 2009). These are the only concentrations greater than 3 |ig/m3
measured at SEWA.
The average acetaldehyde concentration ranges from 0.80 |ig/m3 (2010) to
0.98 |ig/m3 (2009). Confidence intervals calculated indicate that the average
concentrations are not statistically different, although the range of measurements is
lower in more recent years.
There have been no non-detects of acetaldehyde measured since the onset of
sampling.
27-23
-------
Figure 27-16. Annual Statistical Metrics for Acetaldehyde Concentrations
Measured at SEWA
? c
J 6
E
.9
C
1
a
S
1 -
-
T
r t
^M * " ""'
1 ' 1
2007 2008 2009 2010 2011
Year
5th Pe re entile Minimum Median Maximum * 95th Percentile ..^.. Average
Figure 27-17. Annual Statistical Metrics for Arsenic (PMio) Concentrations
Measured at SEWA
* 5th Percentile - Minimum Median - Maximum
95thPercentile ..+.. Average
27-24
-------
Figure 27-18. Annual Statistical Metrics for Benzene Concentrations
Measured at SEWA
!
1
2009
Year
5th Percentile Minimum Median Maximum
95th Percentile
. Average
Figure 27-19. Annual Statistical Metrics for 1,3-Butadiene Concentrations
Measured at SEWA
I
E
.a
E
I
8
a04
c ฐ-4
1
I
T
1 -
^ T
ป.... ... ^^^^^
i
I f * *
2007 2008 2009 2010 2011
Year
* SthPercentile - Minimum Median - Maximum 95th Percentile ..+.. Average
27-25
-------
Figure 27-20. Annual Statistical Metrics for Formaldehyde Concentrations
Measured at SEWA
2009
Year
5th Percentile Minimum Median Maximum
95th Percentile "^"Average
Figure 27-21. Annual Statistical Metrics for Hexavalent Chromium Concentrations
Measured at SEWA
a
ฃ 0.15
zoos
Year
* SthPercentile - Minimum Median - Maximum
95th Percentile
Average
27-26
-------
Figure 27-22. Annual Statistical Metrics for Lead (PMi0) Concentrations
Measured at SEWA
1
Concentration
I
<
M
>....
t
2007
* SthPercentile
^
^g ^^^ ^^_
F"1^"
f I *
2008 2009 2010 2011
Year
Minimum Median Maximum 95th Percentile "^"Average
Figure 27-23. Annual Statistical Metrics for Manganese (PMio) Concentrations
Measured at SEWA
I
.9
E
|
i
2 40
10 -
1 " 1
[
*
* ^
' ' 1 ' 1 ! 1^^^^ 1
2007 2008 2009 2010 2011
Year
* SthPercentile - Minimum Median - Maximum 95th Percentile ..+.. Average
27-27
-------
Observations from Figure 27-17 for arsenic (PMio) measurements at SEWA include the
following:
The maximum arsenic concentration was measured at SEWA on January 19, 2009
(2.69 ng/m3), although a similar concentration was also measured in 2007
(2.56 g/m3).
The average concentration has ranged from 0.58 ng/m3 (2010) to 0.76 |ig/m3 (2007).
The very slight decreasing trend exhibited by the average and median concentrations
is not statistically significant.
There have been no non-detects of arsenic measured since the onset of sampling,
including in 2008, where it appears the minimum concentration is zero. For 2008, the
minimum is 0.011 ng/m3.
Observations from Figure 27-18 for benzene measurements at SEWA include the
following:
The maximum benzene concentration was measured at SEWA on January 19, 2009
3
3
(5.38 |ig/m ), which is the same day the maximum arsenic concentration was
measured. The next highest concentration was roughly half as high (2.48 |ig/nr*,
measured in January 2011). Only five benzene concentrations greater than 2 |ig/m
have been measured at SEWA.
3
The average concentration of benzene ranges from 0.69 |ig/m3 (2010) to 0.81 |ig/m3
(2009). If the maximum concentration measured in 2009 was removed from the
calculation, the averages would vary by less than 0.1 |ig/m3.
Most of the statistical metrics increased at least slightly from 2010 to 2011, with the
exception of the median. The median decreased because the number of concentrations
at the lower end of the range increased from 2010 to 2011 while the average
concentration increased because it is being driven by the higher concentrations
measured in 2011 (the maximum concentration increased by 1 |ig/m3 from 2010 to
2011).
There have been no non-detects of benzene measured since the onset of sampling.
Observations from Figure 27-19 for 1,3-butadiene measurements at SEWA include the
following:
The maximum 1,3-butadiene concentration was measured at SEWA on the same day
as the maximum benzene concentration was measured, January 19, 2009
(0.89 |ig/m3). The next highest concentration was roughly half as high (0.46 |ig/m3)
and was measured on the same day in January 2011 as the second highest benzene
concentration.
27-28
-------
The number non-detects measured at SEWA has been increasing since the onset of
sampling, from 0 percent in 2007 to 15 percent in 2011.
Nearly all of the statistical metrics exhibit an increase from 2010 to 2011. The
average concentration of 1,3-butadiene is at a maximum for 2011 (0.089 |ig/m3),
although confidence intervals calculated for the average concentrations indicate that
the averages are not statistically different.
Observations from Figure 27-20 for formaldehyde measurements at SEWA include the
following:
The maximum formaldehyde concentration was measured at SEWA on
January 13, 2009 (16.6 |ig/m3). The next highest concentration (9.43 |ig/m3) was
measured on the same day in 2007 as the maximum acetaldehyde concentration. Only
one other formaldehyde concentration greater than 3 |ig/m3 has been measured at
SEWA and was also measured in 2009.
The level of variability in the measurements decreased significantly from 2009 to
2010. The difference between the average and median concentrations is less than
0.1 |ig/m3 for both 2010 and 2011.
Although difficult to discern in Figure 27-20, the average concentration increased
slightly from 2010 to 2011, although the average concentrations for both years are the
lowest annual average concentrations of formaldehyde among all NMP sites sampling
this pollutant.
There have been no non-detects of formaldehyde measured since the onset of
sampling.
Observations from Figure 27-21 for hexavalent chromium measurements at SEWA
include the following:
Although SEWA began sampling hexavalent chromium in January 2005, sampling
was discontinued for an eight-month period in 2006 from March through October.
There is no data provided for 2006 in Figure 27-21 because four months is not
considered enough to be representative of an entire year.
The maximum hexavalent chromium concentration shown was measured on
January 19, 2009 (0.232 ng/m3), the same day that the maximum concentration of
several pollutants were measured at SEWA. A similar concentration was measured in
2005 (0.224 ng/m3), also in January.
The minimum and 5th percentiles are zero for each year of sampling shown except
2011, indicating the presence of non-detects. The percentage of non-detects has
ranged from three percent (2011) to 21 percent (2009).
27-29
-------
The average concentration has a decreasing trend beginning in 2008 that continues
through 2010. The median, however, reaches a minimum in 2009 rather than 2010,
even with the maximum hexavalent chromium concentration measured. This is partly
a result of the number of non-detects and thus, zeroes substituted into the calculation.
The number of non-detects is 21 percent for 2009, which decreased to 15 percent for
2010. There were also a higher number of "lower" measurements in 2009; 18
concentrations less than 0.02 ng/m3 were measured in 2009 as opposed to 12 in 2010.
Nearly all of the statistical metrics exhibit increases from 2010 to 2011.
Observations from Figure 27-22 for lead (PMio) measurements at SEWA include the
following:
The maximum lead concentration was measured at SEWA on February 24, 2008
(31.7 ng/m3). Only one additional concentration measured at SEWA is greater than
20 ng/m3 (20.8 ng/m3 measured on July 5, 2007).
A decreasing trend in the average and median lead concentrations is shown in
Figure 27-22. Nearly all of the statistical metrics decreased from 2008 to 2009 and
again for 2010. Slight increases in the statistical metrics are shown for 2011, although
the difference in the average concentrations between 2010 and 2011 is not statistically
significant.
There have been no non-detects of lead measured since the onset of sampling,
including in 2008, where it appears the minimum concentration is zero. For 2008, the
minimum is 0.11 ng/m3.
Observations from Figure 27-23 for manganese (PMio) measurements at SEWA include
the following:
The three highest manganese concentrations measured at SEWA were all measured in
2007 and are the only three measurements greater than 50 ng/m3 measured at this site,
although the maximum concentration measured in 2011 is just less than 50 ng/m3.
A steady decreasing trend in the average manganese concentration is shown through
2010.
Most of the statistical metrics increased from 2010 to 2011. Although the 95th
percentile more than doubled and the average increased by 40 percent, the median
concentration changed only slightly.
There have been no non-detects of manganese measured since the onset of sampling.
27-30
-------
27.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
Washington monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
27.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Washington monitoring site to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual averages were compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
27.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Washington site and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutants of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 27-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
27-31
-------
Table 27-6. Risk Approximations for the Washington Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(Hg/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Seattle, Washington - SEWA
Acetaldehyde
Arsenic (PM10)a
Benzene
Benzo(a)pyrene a
Bery Ilium (PM10)a
1,3 -Butadiene
Cadmium (PM10) a
Carbon Tetrachloride
Chloroform
1 ,2-Dichloroethane
Ethylbenzene
Formaldehyde
Hexavalent Chromium3
Lead(PM10)a
Manganese (PM10) a
Naphthalene a
Nickel (PM10)a
Tetrachloroethylene
Trichloroethylene
Vinyl Chloride
0.0000022
0.0043
0.0000078
0.00176
0.0024
0.00003
0.0018
0.000006
0.000026
0.0000025
0.000013
0.012
0.000034
0.00048
0.00000026
0.0000048
0.0000088
0.009
0.000015
0.03
0.00002
0.002
0.00001
0.1
0.098
2.4
1
0.0098
0.0001
0.00015
0.00005
0.003
0.00009
0.04
0.002
0.1
60/60
61/61
61/61
25/60
61/61
52/61
61/61
61/61
57/61
17/61
61/61
60/60
59/61
61/61
61/61
60/60
61/61
46/61
5/61
1/61
0.94
ฑ0.10
O.01
ฑ<0.01
0.71
ฑ0.11
O.01
ฑ<0.01
0.01
ฑ0.01
0.09
ฑ0.02
0.01
ฑ0.01
0.65
ฑ0.03
0.12
ฑ0.01
0.02
ฑ0.01
0.30
ฑ0.04
0.84
ฑ0.09
0.01
ฑ0.01
O.01
ฑO.01
0.01
ฑ0.01
0.07
ฑ0.01
0.01
ฑ0.01
0.09
ฑ0.02
0.01
ฑ0.01
O.01
ฑ0.01
2.08
2.86
5.56
0.15
0.02
2.66
0.18
3.90
0.63
0.74
10.95
0.40
2.48
0.91
0.02
0.03
0.01
0.10
0.04
0.02
0.01
0.04
0.01
0.01
0.01
O.01
0.01
0.09
0.01
0.02
0.16
0.02
0.02
O.01
O.01
0.01
- = a Cancer URE or Noncancer RfC is not available
a For the annual average concentration of this pollutant in ng/m3, refer to Table 27-5.
27-32
-------
Observations from Table 27-6 for SEWA include the following:
The pollutants with the highest annual averages for SEWA are acetaldehyde,
formaldehyde, benzene, and carbon tetrachloride.
The pollutants with the highest cancer risk approximations are formaldehyde,
benzene, carbon tetrachloride, and arsenic. Although the pollutant with the highest
cancer risk approximation is formaldehyde, its cancer risk approximation is the
lowest among NMP sites sampling carbonyl compounds.
The noncancer hazard approximations for SEWA are all less than 1.0, with the
highest calculated for manganese (0.16), indicating that no adverse health effects are
expected from these individual pollutants.
27.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 27-7 and 27-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 27-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the 10 pollutants with the highest
cancer risk approximations (in-a-million), as calculated from the annual averages provided in
Table 27-6. Table 27-8 presents similar information, but identifies the 10 pollutants with the
highest noncancer hazard approximations (HQ), also calculated from annual averages provided
in Table 27-6.
The pollutants listed in Table 27-7 and 27-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. Further, the cancer risk and noncancer hazard approximations based on each site's annual
averages are limited to those pollutants for which each respective site sampled. As discussed in
Section 27.3, SEWA sampled for VOCs, carbonyl compounds, PAHs, metals (PMio), and
hexavalent chromium. In addition, the cancer risk and noncancer hazard approximations are
limited to those pollutants with enough data to meet the criteria for annual averages to be
calculated. A more in-depth discussion of this analysis is provided in Section 3.5.5.3. Similar to
the cancer risk and noncancer hazard approximations, this analysis may help policy-makers
prioritize their air monitoring activities.
27-33
-------
Table 27-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Washington Monitoring Site
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted
Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Pollutant
Cancer Risk
Approximation
(in-a-million)
Seattle, Washington (King County) - SEWA
Benzene
Formaldehyde
Ethylbenzene
Acetaldehyde
1,3 -Butadiene
Naphthalene
POM, Group 2b
Dichloromethane
POM, Group 6
Nickel, PM
1,542.30
849.03
654.82
430.54
190.09
99.14
28.31
17.29
2.99
2.83
Benzene
Formaldehyde
POM, Group 3
1,3 -Butadiene
Naphthalene
POM, Group 2b
Ethylbenzene
Nickel, PM
Hexavalent Chromium, PM
POM, Group 5a
1.20E-02
1.10E-02
8.19E-03
5.70E-03
3.37E-03
2.49E-03
1.64E-03
1.36E-03
1.34E-03
1.11E-03
Formaldehyde
Benzene
Carbon Tetrachloride
Arsenic
1,3 -Butadiene
Naphthalene
Acetaldehyde
Nickel
Ethylbenzene
1 ,2-Dichloroethane
10.95
5.56
3.90
2.86
2.66
2.48
2.08
0.91
0.74
0.63
to
-------
Table 27-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Washington Monitoring Site
Top 10 Total Emissions for Pollutants with
Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations
Based on Annual Average Concentrations
(Site-Specific)
Pollutant
Noncancer Hazard
Approximation
(HQ)
Seattle, Washington (King County) - SEWA
Toluene
Xylenes
Benzene
Methanol
Formaldehyde
Ethylbenzene
Hexane
Acetaldehyde
1,3 -Butadiene
Ethylene glycol
3,282.31
2,629.14
1,542.30
1,092.81
849.03
654.82
642.62
430.54
190.09
142.99
Acrolein
1,3 -Butadiene
Formaldehyde
Benzene
Acetaldehyde
Naphthalene
Nickel, PM
Xylenes
Lead, PM
Arsenic, PM
2,237,728.52
95,046.24
86,635.26
51,409.86
47,837.23
33,047.76
31,499.47
26,291.40
15,384.07
10,669.99
Manganese
Acetaldehyde
Formaldehyde
Arsenic
1,3 -Butadiene
Naphthalene
Benzene
Nickel
Lead
Cadmium
0.16
0.10
0.09
0.04
0.04
0.02
0.02
0.02
0.02
0.01
to
-------
Observations from Table 27-7 for SEWA include the following:
Benzene, formaldehyde, and ethylbenzene are the highest emitted pollutants with
cancer UREs in King County.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
cancer UREs) for King County are benzene, formaldehyde, and POM, Group 3.
POM, Group 3 does not include any pollutants sampled for at SEWA.
Seven of the highest emitted pollutants also have the highest toxi city-weighted
emissions for King County.
Formaldehyde and benzene have the highest cancer risk approximations for SEWA.
These two pollutants top both emissions-based lists as well. Naphthalene,
1,3-butadiene, ethylbenzene, and nickel also appear on all three lists.
Carbon tetrachloride and arsenic, which rank third and fourth for cancer risk
approximations for SEWA, do not appear on either emissions-based list.
Acetaldehyde has the seventh highest cancer risk approximation and ranks fourth for
total emissions, but ranks 11th for toxicity-weighted emissions and thus, does not
appear in this column in Table 27-7.
POM, Group 2b is the seventh highest emitted "pollutant" in King County and ranks
sixth for toxicity-weighted emissions. POM, Group 2b includes several PAHs
sampled for at SEWA including acenaphthene, fluorene, and perylene. Although none
of the PAHs included in POM, Group 2b were identified as pollutants of interest for
SEWA, acenaphthene failed one screen for SEWA.
POM, Group 5a ranks tenth for toxicity-weighted emissions for King County. POM,
Group 5a includes benzo(a)pyrene and is not one of the highest "pollutants" emitted
in King County.
Observations from Table 27-8 for SEWA include the following:
Toluene, xylenes, and benzene are the highest emitted pollutants with noncancer
RfCs in King County.
Acrolein is the pollutant with the highest toxicity-weighted emissions (of the
pollutants with noncancer RfCs) for King County, followed by 1,3-butadiene and
formaldehyde. Although acrolein was sampled for at SEWA, this pollutant was
excluded from the pollutants of interest designation, and thus subsequent risk-based
screening evaluations, due to questions about the consistency and reliability of the
measurements, as discussed in Section 3.2.
Five of the highest emitted pollutants also have the highest toxicity-weighted
emissions for King County.
27-36
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Manganese, which has the highest noncancer hazard approximation for SEW A, does
not appear on either emissions-based list for King County. Acetaldehyde,
formaldehyde, 1,3-butadiene, and benzene appear on all three lists in Table 27-8.
Three of the four metals that appear among the highest noncancer hazard
approximations for SEWA are also among the pollutants with the highest toxicity-
weighted emissions (arsenic, nickel, and lead). However, none of these are among the
highest emitted pollutants (with a noncancer RfC) in King County.
Naphthalene also has one of the highest noncancer hazard approximations for SEWA
and appears among the pollutants with the highest toxicity-weighted emissions but is
not one of the highest emitted (with a noncancer RfC).
27.6 Summary of the 2011 Monitoring Data for SEWA
Results from several of the data treatments described in this section include the
following:
*ป* Eighteen pollutants failed at least one screen for SEWA, of which 12 are NATTS
MQO Core Analytes.
ปซป Acetaldehyde had the highest annual average concentration for SEWA, although all
of the pollutants of interest for SEWA had annual average concentrations less than
1 ng/m3.
ปซป The annual average concentration of nickel for SEWA is the highest among NMP
sites sampling metals.
ปซป The average concentration for each of the pollutants for which a trends analysis was
performed exhibits a slight increase from 2010 to 2011.
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28.0 Site in Wisconsin
This section examines the spatial and temporal characteristics of the ambient monitoring
concentrations measured at the NATTS site in Wisconsin, and integrates these concentrations
with emissions, meteorological, and risk information. Data generated by sources other than ERG
are not included in the data analyses contained in this report. Readers are encouraged to refer to
Sections 1 through 4 and the glossary (Appendix P) for detailed discussions and definitions
regarding the various data analyses presented below.
28.1 Site Characterization
This section characterizes the monitoring site by providing geographical and physical
information about the location of the site and the surrounding area. This information is provided
to give the reader insight regarding factors that may influence the air quality near the site and
assist in the interpretation of the ambient monitoring measurements.
The HOWI site is located in Horicon, Wisconsin and is the relocated Mayville NATTS
site. Figure 28-1 is a composite satellite image retrieved from ArcGIS Explorer showing the
monitoring site in its rural location. Figure 28-2 identifies nearby point source emissions
locations by source category, as reported in the 2008 NEI for point sources. Note that only
sources within 10 miles of the site are included in the facility counts provided in Figure 28-2.
A 10-mile boundary was chosen to give the reader an indication of which emissions sources and
emissions source categories could potentially have a direct effect on the air quality at the
monitoring site. Further, this boundary provides both the proximity of emissions sources to the
monitoring site as well as the quantity of such sources within a given distance of the site. Sources
outside the 10-mile radius are still visible on the map, but have been grayed out in order to show
emissions sources just outside the boundary. Table 28-1 provides supplemental geographical
information such as land use, location setting, and locational coordinates.
28-1
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Figure 28-1. Horicon, Wisconsin (HOWI) Monitoring Site
to
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to
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Figure 28-2. NEI Point Sources Located Within 10 Miles of HOWI
Legend
HOWI NATTS site
Source Category Group (No. of Facilities)
-f Aircraft Operations (3)
B Automobile/Truck Manufacturing (1)
E Electroplating, Plating, Polishing, Anodizing, & Coloring (1}
0 Fabricated Metal Products (5)
F Food Processing/Agriculture (2)
Lime Manufacturing (1)
5 Miscellaneous Coating Manufacturing (1)
M Miscellaneous Manufacturing (1)
P Printing/Publishing (1)
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Table 28-1. Geographical Information for the Wisconsin Monitoring Site
Site
Code
HOW
AQS Code
55-027-0007
Location
Horicon
County
Dodge
Micro- or
Metropolitan
Statistical Area
Beaver Dam, WI
MSA
Latitude
and
Longitude
43.466111,
-88.621111
Land Use
Agricultural
Location
Setting
Rural
Additional Ambient Monitoring Information1
CO, SO2, NOy, NO, VOCs, Carbonyl compounds, O3,
Meteorological parameters, PM10, PM10 Metals,
PM2 5, and PM2 5 Speciation, SVOCs, PM Coarse.
BOLD ITALICS = EPA-designated NATTS Site
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The HOWI site is located just north of the town of Horicon, in southeast Wisconsin,
within the boundaries of the Horicon Marsh Wildlife Area. HOWI is located about 46 miles
northwest of Milwaukee and roughly 48 miles northeast of Madison. The surrounding area is
rural and agricultural in nature, although a residential subdivision is located just south of the site.
The HOWI monitoring site serves as a rural background site. However, the area is affected by
nearby urban areas, and thus, could show the effects on the wildlife sanctuary. State Highway 28,
which can be seen on the lower right-hand side of Figure 28-1, is the closest major roadway.
Figure 28-2 shows that a cluster of point sources is located just south and west of HOWI, in the
town of Horicon. The closest point source to HOWI is an automobile and truck manufacturing
facility. The source categories with the most emissions sources within 10 miles of HOWI are
fabricated metal products facilities; aircraft operations, which include airports as well as small
runways, heliports, and landing pads; and food processing/agricultural facilities.
Table 28-2 presents additional site-characterizing information, including indicators of
mobile source activity, for the Wisconsin monitoring site. Table 28-2 includes county-level
population and vehicle registration information. Table 28-2 also includes a county-level vehicle
registration-to-population ratio, which was calculated to represent the number of vehicles per
person within the monitoring site's residing county. In addition, the population within 10 miles
of the site is presented, based on postal code population data estimates. An estimate of 10-mile
vehicle ownership was determined by applying the county-level vehicle registration-to-
population ratio to the 10-mile population surrounding the monitoring site. Table 28-2 also
contains traffic volume information for HOWI. Finally, Table 28-2 presents the county-level
daily VMT for Dodge County.
Table 28-2. Population, Motor Vehicle, and Traffic Information for the Wisconsin
Monitoring Site
Site
HOWI
Estimated
County
Population1
88,661
County-level
Vehicle
Registration2
100,176
Vehicles per
Person
(Registration:
Population)
1.13
Population
within 10
miles3
21,990
Estimated
10-mile
Vehicle
Ownership
24,846
Annual
Average
Daily
Traffic4
5,000
County-
level Daily
VMT5
2,626,054
Bounty-level population estimate reflects 2011 data from the U.S. Census Bureau (Census Bureau, 2012b)
2County-level vehicle registration reflects 2011 data from the Wisconsin DOT (WI DOT, 2011)
310-mile population estimate reflects 2011 data from Xionetic (Xionetic, 2011)
4AADT reflects 2008 data from the Wisconsin DOT (WI DOT, 2008)
5County-level VMT reflects 2011 data from the Wisconsin DOT (WI DOT, 2012)
BOLD ITALICS = EPA-designated NATTS Site
28-5
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Observations from Table 28-2 include the following:
Dodge County's population is in the bottom-third compared to other counties with
NMP sites. This is also true of its 10-mile population.
The county-level vehicle registration is also on the low end compared to other
counties with NMP sites. This is also true of its estimated 10-mile vehicle ownership.
The vehicle-per-person ratio is slightly greater than one vehicle per person. This ratio
ranks among the higher ratios for NMP sites.
The traffic volume near HOWI is also on the low end compared to other NMP sites.
The traffic estimate provided is for State Road 28 near State Road 33 on the east side
of Horicon.
The daily VMT for Dodge County is on the low side compared to other counties with
NMP sites (where VMT data were available).
28.2 Meteorological Characterization
The following sections characterize the meteorological conditions near the monitoring
site in Wisconsin on sample days, as well as over the course of the year.
28.2.1 Climate Summary
The town of Horicon is located in southeast Wisconsin, between the towns of West Bend
and Beaver Dam, and about 40 miles west of Lake Michigan. This area is far enough inland to
limit some of the moderating influences of Lake Michigan on the area's climate. This area
experiences a highly variable, continental climate as weather systems frequently track across the
region. Precipitation falls predominantly in the spring and summer months. Winters are cold and
predominantly dry, although snowfall is common. Lake effect snows can occur with winds with
a northeasterly and easterly component, although lake effect snows are often reduced this far
inland. Summers tend to be mild, although southerly winds out of the Gulf of Mexico can
occasionally advect warm, humid air into the area (Bair, 1992).
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28.2.2 Meteorological Conditions in 2011
Hourly meteorological data from the NWS weather station nearest this site were retrieved
for 2011 (NCDC, 2011). The closest weather station is located at Dodge County Airport
(WBAN 04898). Additional information about the Dodge County Airport weather station, such
as the distance between the site and the weather station, is provided in Table 28-3. These data
were used to determine how meteorological conditions on sample days vary from conditions
experienced throughout the year.
Table 28-3 presents average temperature (average maximum and average daily), moisture
(average dew point temperature, average wet bulb temperature, and average relative humidity),
pressure (average sea level pressure), and wind (average scalar wind speed) information for days
samples were collected and for the entire year. Also included in Table 28-3 is the 95 percent
confidence interval for each parameter. As shown in Table 28-3, average meteorological
conditions on sample days appear cooler and drier than average weather conditions throughout
2011, although the differences are not statistically significant.
28.2.3 Back Trajectory Analysis
Figure 28-3 is the composite back trajectory map for days on which samples were
collected at the HOWI monitoring site in 2011. Included in Figure 28-3 are four back trajectories
per sample day. Figure 28-4 is the corresponding cluster analysis. An in-depth description of
these maps and how they were generated is presented in Section 3.5.2.1. For the composite map,
each line represents the 24-hour trajectory along which a parcel of air traveled toward the
monitoring site on a given sample day and time, based on an initial height of 50 meters AGL. For
the cluster analysis, each line corresponds to a trajectory representative of a given cluster of back
trajectories. Each concentric circle around the site in Figures 28-3 and 28-4 represents 100 miles.
28-7
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Table 28-3. Average Meteorological Conditions near the Wisconsin Monitoring Site
Closest NWS
Station
(WBAN and
Coordinates)
Distance
and
Direction
from Site
Average
Type1
Average
Maximum
Temperature
(ฐF)
Average
Temperature
(ฐF)
Average
Dew Point
Temperature
(ฐF)
Average
Wet Bulb
Temperature
(ฐF)
Average
Relative
Humidity
(%)
Average
Sea Level
Pressure
(mb)
Average
Scalar Wind
Speed
(kt)
Horicon, Wisconsin - HOWI
Dodge County
Airport
04898
(43.43, -88.70)
4.64
miles
229ฐ
(SW)
Sample
Day
2011
52.3
ฑ5.5
54.5
+ 2.2
44.9
ฑ5.1
46.6
+ 2.0
34.3
ฑ4.6
36.2
+ 1.8
40.0
ฑ4.5
41.8
+ 1.8
69.7
ฑ3.2
70.7
+ 1.3
NA
NA
6.9
ฑ0.9
6.9
+ 0.3
Sample day averages are highlighted to help differentiate the sample day averages from the full-year averages.
NA = Sea level pressure was not recorded at the Dodge County Airport
-------
Figure 28-3. 2011 Composite Back Trajectory Map for HOWI
-7
Figure 28-4. Back Trajectory Cluster Map for HOWI
28-9
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Observations from Figures 28-3 and 28-4 for HOWI include the following:
Back trajectories originated from a variety of directions at HOWI, although a
majority of the back trajectories originate from a direction with a westerly
component.
The 24-hour air shed domain for HOWI is among the larger in size compared to other
NMP monitoring sites. The farthest away a back trajectory originated was north-
central Montana, or approximately 950 miles away. However, the average trajectory
length was 274 miles and most trajectories (88 percent) originated within 450 miles
of the site.
The cluster analysis shows that about 16 percent of the back trajectories originated
from the north and northeast of HOWI, although of varying distances (10 percent
originated over Lakes Michigan and Superior while another 6 percent originated over
Ontario, Canada). Another 13 percent of back trajectories originated to the north-
northwest to north of HOWI. Ten percent of back trajectories originated to the
northwest and greater than 400 miles away of HOWI. Twenty-seven percent of back
trajectories are represented by the short trajectory originating to the west of the site.
The individual back trajectories represented by this cluster trajectory originated from
the northwest, west, and southwest and within 300 miles of the site. Thirteen percent
of back trajectories originated from the southeast to southwest of the site over Illinois,
Missouri, and Iowa while another 21 percent originated to the east to southeast over
Michigan, Ohio, and Indiana.
28.2.4 Wind Rose Comparison
Hourly surface wind data from the NWS weather station at Dodge County Airport near
HOWI were uploaded into a wind rose software program to produce customized wind roses, as
described in Section 3.5.2.2. A wind rose shows the frequency of wind directions using "petals"
positioned around a 16-point compass, and uses different colors to represent wind speeds.
Figure 28-5 presents a map showing the distance between the NWS station and HOWI,
which may be useful for identifying topographical influences that can affect the meteorological
patterns experienced at this location. Figure 28-5 also presents three different wind roses for the
HOWI monitoring site. First, a historical wind rose representing 2003 to 2010 wind data is
presented, which shows the predominant surface wind speed and direction over an extended
period of time. Second, a wind rose representing wind observations for all of 2011 is presented.
Next, a wind rose representing wind data for days on which samples were collected in 2011 is
presented. These can be used to identify the predominant wind speed and direction for 2011 and
determine if wind observations on sample days were representative of conditions experienced
over the entire year and historically.
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Figure 28-5. Wind Roses for the Dodge County Airport Weather Station near HOWI
Distance between HOWI and NWS Station
2003-2010 Historical Wind Rose
2011 Wind Rose
Sample Day Wind Rose
28-11
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Observations from Figure 28-5 for HOWI include the following:
The Dodge County Airport weather station is located approximately 4.6 miles
southwest of HOWI.
The historical wind rose shows that winds from a variety of directions were observed
near HOWI. Winds from the south, southwest quadrant, and west account for
one-third of wind observations. The strongest wind speeds were associated with
southerly to west-southwesterly winds. Calm winds (<2 knots) were observed for
nearly 15 percent of the hourly measurements.
The wind patterns shown on the 2011 wind rose resemble the historical wind patterns,
although winds from the north were observed more frequently.
The sample day wind rose shows that winds from the north were observed even more
frequently on sample days and that a higher percentage of strong (> 22 knots) winds
were observed for these northerly winds. In addition, winds from the east to southeast
were observed more frequently than winds from the southwest quadrant.
28.3 Pollutants of Interest
Site-specific "pollutants of interest" were determined for the Wisconsin monitoring site
in order to allow analysts and readers to focus on a subset of pollutants through the context of
risk. Each pollutant's preprocessed daily measurement was compared to its associated risk
screening value. If the concentration was greater than the risk screening value, then the
concentration "failed the screen." Pollutants of interest are those for which the individual
pollutant's total failed screens contribute to the top 95 percent of the site's total failed screens. In
addition, if any of the NATTS MQO Core Analytes measured by the monitoring site did not
meet the pollutant of interest criteria based on the preliminary risk-based screening, that pollutant
was added to the list of site-specific pollutants of interest. A more in-depth description of the
risk-based screening process is presented in Section 3.2.
Table 28-4. Risk-Based Screening Results for the Wisconsin Monitoring Site
Pollutant
Screening
Value
(Ug/m3)
#of
Failed
Screens
#of
Measured
Detections
%of
Screens
Failed
% of Total
Failures
Cumulative
%
Contribution
Horicon, Wisconsin - HOWI
Hexavalent Chromium
0.000083
Total
0
0
41
41
0.00
0.00
0.00
0.00
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Table 28-4 presents the results of the preliminary risk-based screening process for
HOWL Observations from Table 28-4 include the following:
Hexavalent chromium was detected in 41 of the 61 valid samples collected at HOWL
Hexavalent chromium did not fail any screens. However, hexavalent chromium is the
pollutant of interest for HOWI because it is a NATTS MQO Core Analyte and
because it is the only pollutant sampled for at HOWI.
28.4 Concentrations
This section presents various concentration averages used to characterize pollution levels
at the Wisconsin monitoring site. Where applicable, the following calculations and data analyses
were performed: Time period-based concentration averages (quarterly and annual) are provided
for the pollutant of interest for the Wisconsin monitoring site, where the data meet the applicable
criteria. Concentration averages for the pollutants of interest are also presented graphically for
the site to illustrate how the site's concentrations compare to the program-level averages, as
presented in Section 4.1. In addition, concentration averages for select pollutants are presented
from previous years of sampling in order to characterize concentration trends at the site.
Additional site-specific statistical summaries for HOWI are provided in Appendix O.
28.4.1 2011 Concentration Averages
Quarterly and annual concentration averages were calculated for the pollutants of interest
for the Wisconsin site, as described in Section 3.1. The quarterly average of a particular
pollutant is simply the average concentration of the preprocessed daily measurements over a
given calendar quarter. Quarterly average concentrations include the substitution of zeros for all
non-detects. A site must have a minimum of 75 percent valid samples of the total number of
samples possible within a given quarter for a quarterly average to be calculated. An annual
average includes all measured detections and substituted zeros for non-detects for the entire year
of sampling. Annual averages were calculated for pollutants where three valid quarterly averages
could be calculated and where method completeness was greater than or equal to 85 percent, as
presented in Section 2.4. Quarterly and annual average concentrations for HOWI are presented in
Table 28-5, where applicable. Note that if a pollutant was not detected in a given calendar
quarter, the quarterly average simply reflects "0" because only zeros substituted for non-detects
were factored into the quarterly average concentration.
28-13
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Table 28-5. Quarterly and Annual Average Concentrations of the Pollutants of
Interest for the Wisconsin Monitoring Site
Pollutant
#of
Measured
Detections
vs. # of
Samples
1st
Quarter
Average
(ng/m3)
2nd
Quarter
Average
(ng/m3)
3rd
Quarter
Average
(ng/m3)
4th
Quarter
Average
(ng/m3)
Annual
Average
(ng/m3)
Horicon, Wisconsin - HOWI
Hexavalent Chromium
41/61
0.004
ฑ 0.004
0.023
ฑ 0.009
0.022
ฑ 0.006
0.010
ฑ 0.007
0.015
ฑ 0.004
NA = Not available due to the criteria for calculating a quarterly and/or annual average
Observations for HOWI from Table 28-5 include the following:
Concentrations of hexavalent chromium spanned an order of magnitude, ranging from
0.0078 ng/m3 to 0.072 ng/m3. The maximum concentration was measured on
May 9, 2011.
Hexavalent chromium was most often detected in the warmer months of the year.
Nine non-detects were measured during the first quarter of 2011, two each in the
second and third quarters, and seven were measured in the fourth quarter of the year.
The annual average concentration of hexavalent chromium for HOWI was on the low
side compared to other NMP sites sampling this pollutant, ranking 15th out 22.
28.4.2 Concentration Comparison
In order to better illustrate how a site's annual average concentrations compare to the
program-level averages, a site-specific box plot was created for the selected NATTS MQO Core
Analytes listed in Section 3.5.3, where applicable. Thus, a box plot for hexavalent chromium was
created for HOWI. Figure 28-6 overlays the site's minimum, annual average, and maximum
concentrations onto the program-level minimum, first quartile, median, average, third quartile,
and maximum concentrations, as described in Section 3.5.3.
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Figure 28-6. Program vs. Site-Specific Average Hexavalent Chromium Concentration
HOWl
0.05
0.1
0.15
Concentration (ng/mi)
0.2
DL25
0.3
Program
Site:
: IstQuartile
Site Average
o
2ndQuartile SrdQuartile 4thQuartile AVE
Site Minimum/Maximum
rage
Observations from Figure 28-6 include the following:
Figure 28-6 shows that the annual average concentration of hexavalent chromium
for HOWI is less than the program-level average as well as the program-level
median concentration. The maximum concentration measured at HOWI is
considerably less than the program-level maximum concentration. There were 20
non-detects of hexavalent chromium measured at HOWI.
28.4.3 Concentration Trends
A site-specific trends evaluation was completed for sites that have sampled one or more
of the selected NATTS MQO Core Analytes for 5 consecutive years or longer, as described in
Section 3.5.4. Because sampling under the NMP did not begin until December 2009 at HOWI, a
trends analysis was not conducted for this site.
28.5 Additional Risk-Based Screening Evaluations
The following risk-based screening evaluations were conducted to characterize risk at the
Wisconsin monitoring site. Refer to Sections 3.3 and 3.5.5 for definitions and explanations
regarding the various toxicity factors, time frames, and calculations associated with these risk-
based screenings.
28.5.1 Risk-Based Screening Assessment Using MRLs
A risk-based screening was conducted by comparing the concentration data from the
Wisconsin monitoring site to the ATSDR MRLs, where available. As described in Section 3.3,
MRLs are noncancer health risk benchmarks and are defined for three exposure periods: acute
(exposures of 1 to 14 days); intermediate (exposures of 15 to 364 days); and chronic (exposures
of 1 year or greater). The preprocessed daily measurements of the pollutants of interest were
28-15
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compared to the acute MRLs; the quarterly averages were compared to the intermediate MRLs;
and the annual average was compared to the chronic MRLs.
As discussed in Section 4.2.2, none of the measured detections or time-period average
concentrations for any of the monitoring sites were greater than their respective ATSDR MRL
noncancer health risk benchmarks for any of the pollutants measured under the NMP for 2011.
28.5.2 Cancer Risk and Noncancer Hazard Approximations
For the pollutants of interest for the Wisconsin site and where annual average
concentrations could be calculated, risk was examined by calculating cancer risk and noncancer
hazard approximations. These approximations can be used as risk estimates for cancer and
noncancer effects attributable to the pollutant of interest. Although the use of these
approximations is limited, they may help identify where policy-makers may want to shift or
confirm their air-monitoring priorities. Refer to Section 3.5.5.2 for an explanation of how cancer
risk and noncancer hazard approximations are calculated and what limitations are associated with
them. Annual averages, cancer UREs and/or noncancer RfCs, and cancer risk and noncancer
hazard approximations are presented in Table 28-6, where applicable. Cancer risk
approximations are presented as probabilities while the noncancer hazard approximations are
ratios and thus, unitless values.
Table 28-6. Risk Approximations for the Wisconsin Monitoring Site
Pollutant
Cancer
URE
(Hg/m3)1
Noncancer
RfC
(mg/m3)
#of
Measured
Detections
vs. # of
Samples
Annual
Average
(ng/m3)
Cancer Risk
Approximation
(in-a-million)
Noncancer
Hazard
Approximation
(HQ)
Horicon, Wisconsin - HOWI
Hexavalent Chromium
0.012
0.0001
41/61
0.015
ฑ 0.004
0.18
0.01
Observations for HOWI from Table 28-6 include the following:
The cancer risk approximation for hexavalent chromium is less than 1.0 in-a-million
(0.18 in-a-million).
The noncancer hazard approximation for hexavalent chromium is less than 1.0,
indicating that no adverse health effects are expected from this pollutant.
28-16
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28.5.3 Risk-Based Emissions Assessment
In addition to the risk-based screenings discussed above, Tables 28-7 and 28-8 present an
evaluation of county-level emissions based on cancer and noncancer toxicity, respectively.
Table 28-7 presents the 10 pollutants with the highest emissions from the 2008 NEI, the
10 pollutants with the highest toxicity-weighted emissions, and the cancer risk approximation for
hexavalent chromium, as calculated from the annual average provided in Table 28-6. Table 28-8
presents similar information, but identifies the noncancer hazard approximation for hexavalent
chromium, also calculated from annual average provided in Table 28-6.
The pollutants listed in Tables 28-7 and 28-8 are limited to those that have cancer and
noncancer toxicity factors, respectively. As a result, although the actual value of the emissions is
the same, the highest emitted pollutants in the cancer table may be different from the noncancer
table. The cancer risk and noncancer hazard approximations based on each site's annual averages
are limited to those pollutants for which each respective site sampled. As discussed in
Section 28.3, HOWI sampled for hexavalent chromium only. In addition, the cancer risk and
noncancer hazard approximations are limited to those pollutants with enough data to meet the
criteria for annual averages to be calculated. A more in-depth discussion of this analysis is
provided in Section 3.5.5.3. Similar to the cancer risk and noncancer hazard approximations, this
analysis may help policy-makers prioritize their air monitoring activities.
Observations from Table 28-7 include the following:
Benzene, formaldehyde, and acetaldehyde are the highest emitted pollutants with
cancer UREs in Dodge County.
Benzene is the pollutant with the highest toxicity-weighted emissions (of the
pollutants with cancer UREs), followed by formaldehyde and hexavalent chromium.
Seven of the highest emitted pollutants in Dodge County also have the highest
toxicity-weighted emissions.
Hexavalent chromium, which is the only pollutant sampled for at HOWI, has the third
highest toxicity-weighted emissions for Dodge County, but is not among the highest
emitted. Hexavalent chromium emissions in Dodge County rank 17th.
Several POM Groups rank among Dodge County's highest total emissions and
toxicity-weighted emissions.
28-17
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Table 28-7. Top 10 Emissions, Toxicity-Weighted Emissions, and Cancer Risk Approximations for Pollutants with Cancer UREs for
the Wisconsin Monitoring Site
Top 10 Total Emissions for Pollutants with
Cancer UREs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Cancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Cancer
Toxicity
Weight
Top 10 Cancer Risk Approximations Based on
Annual Average Concentrations
(Site-Specific)
Cancer Risk
Approximation
Pollutant (in-a-million)
Horicon, Wisconsin (Dodge County) - HOWI
Benzene
Formaldehyde
Acetaldehyde
Ethylbenzene
1,3 -Butadiene
Naphthalene
POM, Group 2b
Tetrachloroethylene
Trichloroethylene
Dichloromethane
90.74
47.98
31.44
26.35
9.67
6.11
1.31
1.00
0.85
0.82
Benzene
Formaldehyde
Hexavalent Chromium, PM
1,3 -Butadiene
Naphthalene
POM, Group 3
POM, Group 2b
POM, Group 5a
Acetaldehyde
Ethylbenzene
7.08E-04
6.24E-04
3.70E-04
2.90E-04
2.08E-04
2.07E-04
1.15E-04
1.12E-04
6.92E-05
6.59E-05
Hexavalent Chromium 0.18
to
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Table 28-8. Top 10 Emissions, Toxicity-Weighted Emissions, and Noncancer Hazard Approximations for Pollutants with Noncancer
RfCs for the Wisconsin Monitoring Site
Top 10 Total Emissions for Pollutants
with Noncancer RfCs
(County-Level)
Pollutant
Emissions
(tpy)
Top 10 Noncancer Toxicity-Weighted Emissions
(County-Level)
Pollutant
Noncancer
Toxicity
Weight
Top 10 Noncancer Hazard Approximations Based
on Annual Average Concentrations
(Site-Specific)
Noncancer Hazard
Approximation
Pollutant (HQ)
Horicon, Wisconsin (Dodge County) - HOWI
Toluene
Xylenes
Methanol
Benzene
Formaldehyde
Methyl isobutyl ketone
Acetaldehyde
Hexane
Hydrochloric acid
Ethylbenzene
329.03
146.74
98.40
90.74
47.98
33.47
31.44
31.15
26.97
26.35
Acrolein
Manganese, PM
Cyanide Compounds, gas
Formaldehyde
1,3 -Butadiene
Acetaldehyde
Benzene
Chlorine
Naphthalene
Xylenes
163,416.51
6,223.90
5,737.27
4,895.94
4,837.37
3,493.32
3,024.81
2,097.57
2,036.14
1,467.40
Hexavalent Chromium O.01
to
oo
-------
Observations from Table 28-8 include the following:
Toluene, xylenes, and methanol are the highest emitted pollutants with noncancer
RfCs in Dodge County.
The pollutants with the highest toxi city-weighted emissions (of the pollutants with
noncancer RfCs) are acrolein, manganese, and cyanide compounds (gaseous).
Five of the highest emitted pollutants in Dodge County also have the highest toxi city-
weighted emissions.
Hexavalent chromium does not appear among the pollutants with the highest
emissions or toxi city-weighted emissions. This pollutant's emissions rank 32nd and its
toxi city-weighted emissions rank 19th (among the pollutants with noncancer RfCs).
28.6 Summary of the 2011 Monitoring Data for HOWI
Results from several of the data treatments described in this section include the
following:
ปซป Hexavalent chromium was the only pollutant sampled for at HO WI and did not fail
any screens.
ปซป Concentrations ofhexavalent chromium measured at HO WI ranged from
0.0078 ng/m3 to 0.072 ng/m3. The annual average concentration ofhexavalent
chromium ranked 15th compared to other NMP sites sampling this pollutant.
ปซป Hexavalent chromium has the third highest toxicity-weighted emissions for Dodge
County, but is not among the highest emitted.
28-20
-------
29.0 Data Quality
This section discusses the data quality of the ambient air measurements that constitute the
2011 NMP dataset. Each monitoring program under the NMP has its own specific DQO(s) which
have been established and approved by EPA, consistent with the specific data use needs of the
individual monitoring program. Because the DQOs are program-specific and the ERG laboratory
is contracted to perform services for a subset of the overall program participants, attainment of
the individual program DQO(s) is not assessed in this report. This section establishes data
quality through the assessment of Data Quality Indicators (DQI) in the form of Measurement
Quality Objectives (MQOs) specific to the program elements conducted by the ERG laboratory.
MQOs are designed to control and evaluate the various phases of the measurement process
(sampling, preparation, analysis, etc.) to ensure that the total measurement quality meets the
overall program data quality needs. In accordance with ERG's EPA-approved QAPP (ERG,
2011), the following MQOs were assessed: completeness, precision, and accuracy (also called
bias).
The quality assessments presented in this section show that the 2011 monitoring data are
of a known and high quality, consistent with the intended data use. The overall method-specific
completeness was greater than 90 percent for each method. The method precision for collocated
and duplicate analyses met the precision MQO of 15 percent CV for all methods. The analytical
precision for replicate analyses also met the precision MQO of 15 percent CV. Audit samples
show that ERG is meeting the accuracy requirements of the NATTS TAD (EPA, 2009b). These
data quality indicators are discussed in further detail in the following sections.
29.1 Completeness
Completeness refers to the number of valid samples actually collected and analyzed
compared to the number of total samples scheduled to be collected and analyzed. The MQO for
completeness based on the EPA-approved QAPP specifies that at least 85 percent of samples
collected at a given monitoring site must be analyzed successfully to be considered sufficient for
data trends analysis (ERG, 2011). The MQO of 85 percent completeness was met by all but
seven out of 123 site-method combinations. Completeness statistics are presented and discussed
more thoroughly in Section 2.4.
29-1
-------
29.2 Method Precision
Precision defines the level of agreement between independent measurements performed
according to identical protocols and procedures. Method precision, which includes sampling and
analytical precision, quantifies random errors associated with collecting ambient air samples and
analyzing the samples in the laboratory. Method precision is evaluated by comparing
concentrations measured in duplicate or collocated samples. A duplicate sample is a sample
collected simultaneously with a primary sample using the same sampling system (i.e., two
separate samples through the same sampling system at the same time). This simultaneous
collection is typically achieved by teeing the line from the sampler to two canisters (or other
sampling media) and doubling the flow rate applied to achieve integration over the 24-hour
collection period. Collocated samples are samples collected simultaneously using two
independent collection systems at the same location at the same time.
Both approaches provide valuable, but different, assessments of method precision:
Analysis of duplicate samples provides information on the potential for variability (or
precision) expected from a single collection system (intra-system assessment).
Analysis of collocated samples provides information on the potential for variability
(or precision) expected between different collection systems (inter-system
assessment).
During the 2011 sampling year, duplicate and collocated samples were collected on at
least 10 percent of the scheduled sample days, as outlined in the EPA-approved QAPP. This
provides a minimum of six pairs of either duplicate or collocated samples per site and method.
For the VOC, SNMOC, and carbonyl compound methods, samples may be duplicate or
collocated. For PAHs, metals, and hexavalent chromium, only collocated samples may be
collected due to limitations of the sampling media/instrumentation. These duplicate or collocated
samples were then analyzed in replicate. Replicate measurements are repeated analyses
performed on a duplicate or collocated pair of samples and are discussed in greater detail in
Section 29.3.
29-2
-------
Method precision was calculated by comparing the concentrations of the
duplicates/collocates for each pollutant. The CV for duplicate or collocated samples was
calculated for each pollutant and each site. The following approach was employed to estimate
how closely the collected and analyzed samples agree with one another:
Coefficient of Variation (CV) provides a relative measure of data dispersion compared to the
mean. A coefficient of variation of one percent would indicate that the analytical results
could vary slightly due to sampling error, while a variation of 50 percent means that the
results are more imprecise.
(p-r) l2
2n
i
Where:
p = the primary result from a duplicate or collocated pair;
r = the secondary result from a duplicate or collocated pair;
n = the number of valid data pairs (the 2 adjusts for the fact that there are two
values with error).
Coefficients of variation were based on every pair of duplicate or collocated samples
collected during the program year. However, only results at or above the MDL were used in
these calculations. Thus, the number of pairs included in the calculations varies significantly
from pollutant to pollutant. This is a change in procedure compared to NMP reports prior to
2010, where 1/2 MDL was substituted for non-detects. To make an overall estimate of method
precision, program-level average CVs were calculated as follows:
A pollutant-specific CV was calculated for each monitoring site.
A site-specific CV was calculated for each method.
A method-specific CV was calculated and compared to the precision MQO.
Table 29-1 presents the 2011 NMP method precision for VOCs, SNMOCs, carbonyl
compounds, PAHs, metals, and hexavalent chromium, presented as the average CV (expressed as
a percentage). Each analytical method met the program MQO of 15 percent CV for method
precision. This table also includes the number of pairs that were included in the calculation of the
method precision. The number of pairs including those with concentrations less than the MDL is
also included in Table 29-1 to provide an indication of the effect that excluding those with
concentrations less than the MDL has on the population of pairs in the dataset.
29-3
-------
Table 29-1. Method Precision by Analytical Method
Method/Pollutant
Group
voc
(TO- 15)
SNMOC
Carbonyl Compounds
(TO- 11 A)
PAH
(TO-13)
Metals Analysis
(Method IO-3. 5)
Hexavalent Chromium
(EPA-approved method)
MQO
Average
Coefficient of
Variation
(%)
11.88
11.59
6.83
11.83
13.58
14.54
Number of
Pairs Included
in the
Calculation
2,971
1,176
1,540
375
1,506
110
Total Number
of Pairs Without
the > MDL
exclusion
3,773
1,614
1,541
488
1,854
118
15.00 percent CV
Tables 29-2 through 29-7 present method precision for VOCs, SNMOCs, carbonyl
compounds, PAHs, metals, and hexavalent chromium, respectively, as the CV per pollutant per
site, and the average CV per site, per pollutant, and per method. Also included in these tables is
the number of duplicate and/or collocated pairs included in the CV calculations. The shaded
rows in each table identify the NATTS MQO Core Analytes for each method. CVs exceeding the
15 percent MQO are bolded in each table. The CVs that exceed the program MQO for precision
are often driven by relatively low concentrations, even though they are greater than the MDL, as
these may result in relatively large CVs (i.e., the concentration difference between 0.01 ng/m3
and 0.02 ng/m3 is 100 percent).
29.2.1 VOC Method Precision
Table 29-2 presents the method precision for all duplicate and collocated VOC samples
as the CV per pollutant per site, the average CV per site, the average CV per pollutant, and the
overall average CV for NMP sites sampling VOCs. The pollutant-specific CV ranged from
0 percent for a few pollutants for several sites to 134.72 percent (carbon disulfide for GLKY).
The pollutant-specific average CV ranged from 0 percent (a few pollutants) to 42.77 percent
(dibromochloromethane). Note that in these cases, the number of pairs included in the
calculations are low. The site-specific average CV ranged from 7.26 percent for S4MO to
20.00 percent for GLKY. The overall average method precision for VOCs was 11.88 percent.
29-4
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethylene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 , 3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Acrylate
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 , 3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
Methyl ter/-Butyl Ether
BTUT
5.51
NA
NA
17.92
NA
NA
NA
31.09
10.60
35.12
6.48
NA
39.12
3.57
6.39
NA
NA
NA
NA
NA
NA
NA
4.70
NA
10.28
0.00
NA
0.00
13.31
NA
NA
NA
7.47
NA
NA
8.27
NA
NA
15.67
NA
NA
BURVT
5.96
25.98
NA
8.61
NA
NA
NA
11.96
6.58
NA
22.80
NA
5.66
14.59
14.08
NA
NA
NA
NA
NA
NA
NA
7.36
NA
12.46
NA
NA
NA
38.38
NA
NA
NA
7.65
NA
NA
9.63
NA
NA
25.98
NA
NA
CHNJ
5.81
21.63
NA
6.36
NA
NA
NA
21.94
19.37
18.31
11.85
NA
18.86
13.41
10.91
NA
NA
NA
NA
NA
NA
NA
7.01
NA
0.00
NA
NA
NA
22.91
NA
NA
NA
14.02
NA
NA
8.53
NA
NA
10.88
NA
NA
DEMI
6.09
NA
NA
4.24
NA
NA
NA
3.37
6.71
18.74
7.94
NA
11.22
34.72
6.97
NA
NA
NA
NA
NA
NA
NA
6.54
NA
3.63
NA
NA
NA
16.61
NA
NA
NA
6.29
NA
NA
7.74
NA
NA
18.05
NA
NA
ELNJ
8.41
37.52
NA
9.93
NA
NA
NA
14.70
9.09
9.11
11.93
NA
8.32
9.56
8.43
NA
NA
NA
NA
NA
NA
3.82
8.32
NA
0.00
NA
NA
NA
9.59
NA
NA
NA
8.78
NA
NA
6.29
NA
NA
30.11
3.93
7.14
GLKY
5.27
81.91
NA
6.14
NA
NA
NA
8.69
20.13
134.72
4.34
NA
NA
4.76
5.98
NA
NA
NA
NA
NA
NA
NA
4.69
NA
4.04
NA
NA
NA
43.48
NA
NA
NA
3.21
NA
NA
15.26
NA
NA
32.47
NA
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method
is calculated from the site-specific averages and provided in the final column of the table.
29-5
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site (Continued)
Pollutant
w-Octane
Propylene
Styrene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1 , 1 ,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
BTUT
11.63
11.23
10.85
NA
6.67
8.14
NA
NA
NA
NA
5.18
4.78
8.97
16.52
NA
8.27
9.58
11.33
BURVT
11.26
13.72
11.18
NA
5.52
12.82
NA
NA
NA
NA
4.99
4.98
11.08
6.86
NA
11.54
9.80
12.36
CHNJ
12.50
7.21
9.07
NA
13.82
14.42
NA
NA
NA
NA
7.12
8.40
6.34
7.71
NA
9.08
8.22
11.69
DEMI
6.68
6.37
5.55
NA
5.99
11.00
NA
NA
NA
NA
4.15
3.51
12.03
7.10
NA
8.62
8.96
9.19
ELNJ
7.76
10.05
11.25
NA
9.69
5.10
NA
NA
NA
NA
8.44
8.08
8.92
10.93
NA
6.45
6.98
9.95
GLKY
15.70
11.64
11.80
NA
NA
15.50
NA
NA
NA
NA
3.11
2.91
9.09
NA
NA
20.64
14.41
20.00
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method
is calculated from the site-specific averages and provided in the final column of the table.
29-6
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site (Continued)
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethylene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 , 3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Acrylate
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
Methyl tert-Butyl Ether
GPCO
3.10
1.91
NA
5.76
NA
NA
NA
11.58
5.48
10.17
27.27
NA
2.24
7.07
1.77
NA
NA
NA
NA
NA
NA
NA
1.92
NA
0.00
NA
NA
NA
21.33
NA
NA
NA
4.66
NA
NA
29.96
NA
NA
15.80
NA
NA
MWOK
3.44
NA
NA
3.94
NA
NA
NA
57.64
3.81
NA
8.39
NA
NA
4.04
7.71
NA
NA
NA
NA
NA
NA
NA
3.13
NA
0.00
NA
NA
NA
8.82
NA
NA
NA
4.14
NA
NA
6.17
NA
NA
17.78
NA
NA
NBIL
2.16
13.58
NA
15.01
NA
41.30
34.49
10.68
6.17
7.78
20.65
NA
10.27
34.50
4.35
NA
NA
42.77
NA
NA
NA
NA
2.77
NA
5.00
NA
NA
NA
30.01
NA
NA
NA
4.74
NA
NA
6.72
NA
NA
24.84
NA
NA
NBNJ
8.12
NA
NA
23.48
NA
NA
NA
18.21
7.19
15.72
11.88
NA
40.41
11.61
6.08
NA
NA
NA
NA
NA
NA
NA
6.38
NA
3.29
NA
NA
NA
14.40
NA
NA
NA
13.33
NA
NA
13.01
NA
NA
10.03
NA
6.15
OCOK
36.98
NA
NA
53.15
NA
NA
NA
13.55
70.59
NA
20.39
NA
NA
0.00
2.26
NA
NA
NA
NA
NA
NA
NA
2.32
NA
NA
NA
NA
NA
7.42
NA
NA
NA
5.43
NA
NA
14.88
NA
NA
25.67
NA
NA
PANJ
6.97
NA
NA
13.66
NA
NA
NA
8.84
2.28
NA
10.88
NA
19.00
1.75
4.81
NA
NA
NA
NA
NA
NA
72.04
8.69
NA
0.00
NA
NA
NA
0.20
NA
NA
NA
9.87
NA
NA
9.85
NA
NA
39.31
NA
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method
is calculated from the site-specific averages and provided in the final column of the table.
29-7
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site (Continued)
Pollutant
w-Octane
Propylene
Styrene
1, 1,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1 , 1 ,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
GPCO
19.10
2.94
19.64
NA
6.85
15.86
NA
NA
NA
1.17
2.83
3.14
54.82
53.68
NA
39.37
38.85
14.58
MWOK
8.97
5.89
8.40
NA
7.96
5.71
NA
NA
NA
NA
3.33
4.31
13.85
9.85
NA
8.02
12.84
9.09
NBIL
13.91
4.53
8.52
NA
5.16
6.38
NA
NA
NA
NA
4.37
1.86
11.81
10.44
NA
6.77
6.76
13.28
NBNJ
8.91
14.87
10.10
NA
16.00
9.35
NA
NA
NA
NA
6.13
12.31
6.93
8.93
NA
14.41
13.57
12.25
OCOK
10.05
56.41
26.16
NA
0.75
32.49
NA
NA
NA
NA
3.11
4.43
17.64
12.03
NA
13.16
25.33
19.75
PANJ
19.96
0.37
10.88
NA
5.14
19.92
NA
NA
NA
NA
10.07
7.07
32.12
25.63
NA
17.95
20.20
14.52
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method
is calculated from the site-specific averages and provided in the final column of the table.
29-8
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site (Continued)
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethylene
/raซ5-l,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 , 3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Aery late
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
Methyl ter/-Butyl Ether
PROK
9.63
33.67
NA
11.22
NA
NA
NA
8.99
10.24
NA
25.33
NA
5.66
NA
8.53
NA
NA
NA
NA
NA
NA
44.84
7.73
NA
14.43
NA
NA
NA
8.60
NA
NA
NA
8.70
NA
NA
12.88
NA
NA
21.81
NA
NA
PXSS
4.70
NA
NA
6.96
NA
NA
NA
3.41
4.11
51.10
8.10
NA
0.00
5.14
3.47
NA
NA
NA
NA
NA
NA
2.44
3.50
NA
6.73
NA
NA
NA
58.38
NA
NA
NA
5.61
NA
NA
4.06
NA
NA
17.20
NA
NA
S4MO
4.91
NA
NA
5.83
NA
NA
NA
8.50
5.26
5.16
6.54
NA
3.45
3.74
7.17
NA
NA
NA
NA
NA
NA
5.74
3.66
NA
8.87
NA
NA
NA
10.94
NA
NA
NA
4.55
NA
NA
4.82
NA
NA
7.58
NA
NA
SEWA
4.00
NA
NA
4.62
NA
NA
NA
11.65
5.02
NA
13.14
NA
NA
16.59
4.35
NA
NA
NA
NA
NA
NA
NA
4.01
NA
11.47
NA
NA
NA
68.48
NA
NA
NA
30.09
NA
NA
5.87
NA
NA
20.19
NA
NA
SPIL
3.02
4.81
NA
8.71
NA
NA
NA
4.35
28.49
3.80
12.38
NA
5.24
14.29
3.91
NA
NA
NA
NA
NA
NA
NA
5.65
NA
9.67
NA
NA
NA
9.73
NA
NA
NA
3.42
NA
NA
32.32
NA
NA
7.33
NA
NA
SSSD
5.55
NA
NA
9.01
NA
NA
NA
9.35
7.39
NA
43.22
NA
4.88
0.00
6.19
NA
NA
NA
NA
NA
NA
NA
4.80
NA
3.86
NA
NA
NA
11.40
NA
NA
NA
6.00
NA
NA
3.77
NA
NA
23.38
NA
26.93
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method
is calculated from the site-specific averages and provided in the final column of the table.
29-9
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site (Continued)
Pollutant
w-Octane
Propylene
Styrene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1 , 1 ,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
PROK
27.83
7.35
11.33
NA
NA
10.40
NA
NA
NA
NA
8.00
8.60
12.69
NA
NA
12.37
16.50
14.47
PXSS
6.15
3.78
5.21
NA
5.47
4.83
NA
NA
NA
NA
3.32
4.03
4.27
3.08
NA
4.88
4.14
8.67
S4MO
7.13
6.76
19.41
NA
11.67
3.79
NA
NA
NA
NA
4.05
5.02
13.22
24.70
0.00
4.31
6.60
7.26
SEWA
11.41
4.11
10.68
NA
0.88
7.13
NA
NA
NA
5.44
4.20
5.46
6.61
1.71
NA
5.01
5.74
10.71
SPIL
7.17
16.63
4.05
NA
3.76
6.68
NA
NA
NA
7.67
5.14
5.57
12.85
3.54
NA
32.71
8.60
9.70
SSSD
10.20
8.77
5.83
NA
NA
7.52
NA
NA
NA
NA
4.25
4.86
6.57
5.26
NA
5.59
4.98
9.18
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method
is calculated from the site-specific averages and provided in the final column of the table.
29-10
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site (Continued)
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1 ,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethylene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 ,3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Acrylate
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
Methyl tert-Butyl Ether
TMOK
3.85
17.16
NA
6.50
NA
NA
NA
9.01
6.15
31.95
27.46
NA
5.24
6.43
3.92
NA
NA
NA
NA
NA
NA
NA
4.15
NA
2.57
NA
NA
NA
4.95
NA
NA
NA
3.60
NA
NA
15.25
NA
NA
51.20
NA
NA
TOOK
5.84
NA
NA
12.52
NA
NA
NA
8.74
13.05
NA
8.21
NA
22.52
3.14
6.98
NA
NA
NA
NA
NA
NA
26.05
4.30
NA
0.00
NA
NA
NA
13.52
NA
NA
NA
7.90
NA
NA
9.11
NA
NA
10.53
NA
NA
UCSD
6.32
22.48
NA
9.13
NA
NA
NA
7.41
0.00
8.17
10.85
NA
18.27
NA
6.67
NA
NA
NA
NA
NA
NA
NA
5.51
NA
5.39
NA
NA
NA
17.19
NA
NA
NA
5.04
NA
NA
8.83
NA
NA
6.95
NA
NA
#of
Pairs
139
17
NA
139
NA
6
1
89
123
56
138
NA
22
62
139
NA
NA
5
NA
NA
NA
11
139
NA
35
1
NA
1
136
NA
NA
NA
138
NA
NA
138
NA
NA
101
1
5
Average by
Pollutant
6.94
26.07
NA
11.56
NA
41.30
34.49
13.51
11.80
26.91
15.24
NA
12.96
9.94
6.24
NA
NA
42.77
NA
NA
NA
25.82
5.10
NA
5.08
0.00
NA
0.00
20.46
NA
NA
NA
7.83
NA
NA
11.10
NA
NA
20.61
3.93
13.41
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29-11
-------
Table 29-2. VOC Method Precision: Coefficient of Variation Based on Duplicate and
Collocated Samples by Site (Continued)
Pollutant
w-Octane
Propylene
Styrene
1, 1,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1,1,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 , 3 ,5 -Trimethy Ibenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
TMOK
8.51
5.59
21.97
NA
8.00
15.13
NA
NA
NA
NA
3.54
6.34
30.10
8.50
NA
20.61
26.26
13.11
TOOK
10.31
38.67
3.79
NA
8.32
16.00
NA
NA
NA
NA
6.21
4.89
5.09
5.56
NA
6.83
7.68
10.22
UCSD
8.53
15.05
19.03
NA
3.82
6.54
NA
NA
NA
NA
5.64
5.14
0.00
NA
0.00
5.08
4.52
8.14
#of
Pairs
134
139
112
NA
61
139
NA
NA
NA
5
139
139
126
65
2
135
133
-
Average by
Pollutant
11.60
12.00
11.65
NA
6.97
11.18
NA
NA
NA
4.76
5.10
5.51
13.57
12.34
0.00
12.46
12.41
11.88
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29.2.2 SNMOC Method Precision
The SNMOC method precision for duplicate and collocated samples is presented in
Table 29-3 as the CV per pollutant per site, the average CV per site, the average CV per
pollutant, and the overall average CV for NMP sites sampling SNMOCs. The results from
duplicate and collocated samples show low- to high-level variability among pollutants and sites,
ranging from a CV of 0 percent (1,3-butadiene for RICO) to 111.81 percent (cyclopentene for
RICO). The pollutant-specific average CV ranged from 0.76 percent (w-tridecane) to
36.81 percent (cyclopentene). Note that in these cases, the number of pairs included in the
calculations is low. The site-specific average CV ranged from 6.69 percent for RICO to
16.27 percent for PACO, with an overall method average of 11.59 percent.
29-12
-------
Table 29-3. SNMOC Method Precision: Coefficient of Variation
Based on Duplicate and Collocated Samples by Site
Pollutant
Acetylene
Benzene
1,3 -Butadiene
w-Butane
c/s-2-Butene
/raws-2-Butene
Cyclohexane
Cyclopentane
Cyclopentene
w-Decane
1-Decene
/w-Diethylbenzene
ฃ>-Diethylbenzene
2,2-Dimethylbutane
2,3 -Dimethylbutane
2,3 -Dimethylpentane
2,4-Dimethylpentane
w-Dodecane
1-Dodecene
Ethane
2-Ethyl-l-butene
Ethylbenzene
Ethylene
/w-Ethyltoluene
o-Ethyltoluene
ฃ>-Ethyltoluene
w-Heptane
1-Heptene
w-Hexane
1-Hexene
c/s-2-Hexene
/raซs-2-Hexene
Isobutane
Isobutene/ 1 -Butene
Isopentane
Isoprene
Isopropylbenzene
2-Methyl-l-butene
3-Methyl-l-butene
2-Methyl- 1 -pentene
BMCO
4.20
22.62
NA
NA
4.36
14.36
8.57
6.45
9.75
7.24
NA
3.45
38.12
7.55
NA
NA
9.00
1.89
0.96
1.93
NA
18.13
1.15
12.65
9.30
NA
20.04
NA
20.87
NA
NA
NA
2.14
NA
7.14
NA
NA
4.03
NA
NA
BTUT
8.69
5.52
10.57
1.68
4.23
50.21
6.25
9.97
39.65
9.69
NA
22.32
16.52
6.08
11.78
8.88
11.83
8.36
18.21
1.04
NA
6.34
4.40
8.11
6.02
11.13
4.56
NA
3.46
NA
NA
NA
1.47
12.05
9.62
9.43
NA
7.31
NA
NA
NBIL
5.66
14.77
NA
8.94
NA
18.46
9.98
13.04
15.48
24.07
29.73
14.44
20.92
9.21
7.34
11.15
7.69
33.55
NA
22.69
NA
10.36
5.26
18.53
11.82
13.54
11.93
NA
11.54
NA
NA
NA
10.74
11.60
11.44
12.08
NA
NA
NA
NA
PACO
18.44
6.46
NA
3.24
5.37
34.08
36.80
18.69
7.37
6.79
NA
9.29
12.67
22.02
2.83
4.48
5.91
9.73
NA
35.08
NA
9.79
2.57
8.25
4.99
4.00
32.07
3.88
34.26
NA
NA
NA
39.12
6.21
28.73
6.70
3.43
NA
NA
NA
RICO
1.66
10.17
0.00
5.83
7.22
6.57
0.39
1.32
111.81
4.14
NA
5.10
17.46
4.82
5.36
4.27
9.64
2.81
8.34
0.36
NA
3.99
2.81
1.47
20.72
8.00
1.99
0.45
4.05
NA
NA
NA
2.17
NA
8.26
2.89
NA
1.76
NA
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29-13
-------
Table 29-3. SNMOC Method Precision: Coefficient of Variation
Based on Duplicate and Collocated Samples by Site (Continued)
Pollutant
4-Methyl- 1 -pentene
2-Methyl-2-butene
Methylcyclohexane
Methylcyclopentane
2-Methylheptane
3-Methylheptane
2-Methylhexane
3-Methylhexane
2-Methylpentane
3-Methylpentane
w-Nonane
1-Nonene
w-Octane
1-Octene
w-Pentane
1 -Pentene
c/s-2-Pentene
/raws-2-Pentene
a-Pinene
6-Pinene
Propane
w-Propylbenzene
Propylene
Propyne
Styrene
Toluene
w-Tridecane
1-Tridecene
1 ,2,3 -Trimethylbenzene
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
2,2,3-Trimethylpentane
2,2,4-Trimethylpentane
2,3 ,4-Trimethylpentane
w-Undecane
1-Undecene
7w-Xylene//?-Xylene
o-Xylene
Average by Site
BMCO
NA
7.74
15.38
14.63
13.95
31.78
13.08
10.64
15.53
12.16
20.71
NA
9.62
NA
12.74
2.90
NA
NA
NA
NA
7.05
5.71
10.71
NA
NA
37.22
NA
NA
22.81
16.26
26.94
NA
NA
19.21
4.53
NA
NA
25.65
12.61
BTUT
NA
9.85
4.52
3.98
7.13
5.22
5.92
5.25
5.00
6.22
7.72
NA
11.73
NA
11.42
14.86
NA
6.08
32.81
2.42
1.56
3.81
6.44
NA
4.06
6.11
0.76
NA
8.99
6.66
1.77
2.37
8.49
6.78
10.48
3.39
9.26
5.68
8.92
NBIL
NA
7.59
16.85
10.24
40.13
29.85
23.77
14.86
11.62
9.11
19.61
33.64
15.90
NA
5.64
17.33
NA
2.02
5.58
NA
19.53
15.61
5.11
29.19
NA
8.03
NA
NA
17.02
13.79
26.54
0.14
9.18
5.17
24.29
41.10
8.98
11.73
15.17
PACO
NA
11.80
30.65
31.27
26.98
26.69
2.21
25.51
20.66
28.04
15.72
10.90
30.03
8.64
57.12
24.34
NA
5.81
NA
NA
39.92
7.14
7.95
NA
NA
27.29
NA
NA
2.13
6.45
2.64
1.65
1.75
11.39
3.54
67.91
0.67
15.98
16.27
RICO
NA
1.78
1.52
0.70
1.28
6.31
2.51
5.01
2.57
0.84
2.35
NA
2.22
NA
3.63
5.26
9.30
3.59
7.64
NA
2.07
4.88
13.60
NA
NA
1.83
NA
NA
4.25
2.76
2.57
NA
17.52
1.68
13.74
NA
4.48
3.25
6.69
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29-14
-------
Table 29-3. SNMOC Method Precision: Coefficient of Variation
Based on Duplicate and Collocated Samples by Site (Continued)
Pollutant
Acetylene
Benzene
1,3 -Butadiene
w-Butane
c/s-2-Butene
/raซs-2-Butene
Cyclohexane
Cyclopentane
Cyclopentene
w-Decane
1-Decene
/w-Diethylbenzene
/>-Diethylbenzene
2,2-Dimethylbutane
2,3 -Dimethylbutane
2,3 -Dimethylpentane
2,4-Dimethylpentane
w-Dodecane
1-Dodecene
Ethane
2-Ethyl-l-butene
Ethylbenzene
Ethylene
/w-Ethyltoluene
o-Ethyltoluene
/>-Ethyltoluene
w-Heptane
1-Heptene
w-Hexane
1-Hexene
c/s-2-Hexene
/raซs-2-Hexene
Isobutane
Isobutene/ 1 -Butene
Isopentane
Isoprene
Isopropylbenzene
2-Methyl-l-butene
3 -Methyl- 1 -butene
2-Methyl- 1 -pentene
SSSD
2.28
8.23
NA
2.98
4.19
5.83
11.88
21.14
NA
2.54
NA
13.14
13.70
9.18
5.36
1.36
3.57
8.46
52.37
1.40
NA
12.75
3.21
5.85
2.50
3.36
3.04
NA
7.44
NA
NA
NA
19.56
23.99
25.45
2.58
NA
14.61
NA
NA
UCSD
3.38
8.39
NA
2.73
NA
15.99
3.04
17.78
NA
NA
NA
15.39
4.43
3.53
4.30
NA
NA
10.69
90.37
1.52
NA
13.86
4.70
NA
NA
NA
3.26
NA
5.59
NA
NA
NA
5.13
5.38
15.82
3.19
NA
NA
NA
NA
#of
Pairs
30
29
3
20
10
16
22
24
6
19
1
25
21
26
16
15
16
19
8
30
0
26
30
19
15
8
22
3
29
0
0
0
30
11
28
16
1
10
0
0
Average
by
Pollutant
6.33
10.88
5.28
4.23
5.07
20.79
10.99
12.62
36.81
9.08
29.73
11.87
17.69
8.91
6.16
6.03
7.94
10.78
34.05
9.15
NA
10.74
3.44
9.14
9.23
8.00
10.98
2.17
12.46
NA
NA
NA
11.48
11.85
15.21
6.15
3.43
6.93
NA
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall
average CV for this method is calculated from the site-specific averages and provided
in the final column of the table.
29-15
-------
Table 29-3. SNMOC Method Precision: Coefficient of Variation
Based on Duplicate and Collocated Samples by Site (Continued)
Pollutant
4-Methyl- 1 -pentene
2-Methyl-2-butene
Methylcyclohexane
Methylcyclopentane
2-Methylheptane
3-Methylheptane
2-Methylhexane
3 -Methy Ihexane
2-Methylpentane
3-Methylpentane
w-Nonane
1-Nonene
w-Octane
1-Octene
w-Pentane
1 -Pentene
cis-2 -Pentene
/raซs-2-Pentene
a-Pinene
6-Pinene
Propane
w-Propylbenzene
Propylene
Propyne
Styrene
Toluene
w-Tridecane
1-Tridecene
1 ,2,3 -Trimethylbenzene
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
2,2,3 -Trimethylpentane
2,2,4-Trimethylpentane
2,3 ,4-Trimethylpentane
w-Undecane
1-Undecene
/w-Xylene/p-Xylene
o-Xylene
Average by Site
SSSD
NA
NA
3.24
7.61
NA
NA
18.37
11.79
23.06
10.01
1.25
NA
3.00
NA
47.27
18.88
NA
7.37
3.89
NA
1.40
NA
5.38
NA
1.72
13.23
NA
NA
6.83
12.98
6.76
NA
10.00
17.81
20.84
NA
1.04
7.20
10.43
UCSD
NA
NA
0.68
13.90
NA
NA
10.78
18.73
5.68
5.24
NA
NA
NA
NA
19.65
30.02
NA
NA
NA
NA
2.25
NA
11.97
NA
17.40
7.22
NA
NA
NA
9.76
NA
NA
3.58
NA
NA
14.34
3.91
4.30
11.00
#of
Pairs
0
13
22
27
12
12
26
26
30
28
18
3
18
1
30
22
1
17
5
1
30
7
30
1
3
29
2
0
14
27
12
4
24
18
16
4
15
24
~
Average
by
Pollutant
NA
7.75
10.41
11.76
17.89
19.97
10.95
13.11
12.02
10.23
11.23
22.27
12.09
8.64
22.49
16.23
9.30
4.97
12.48
2.42
10.54
7.43
8.74
29.19
7.73
14.42
0.76
NA
10.34
9.81
11.20
1.39
8.42
10.34
12.90
31.68
4.72
10.54
11.59
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall
average CV for this method is calculated from the site-specific averages and provided
in the final column of the table.
29-16
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29.2.3 Carbonyl Compound Method Precision
Table 29-4 presents the method precision for duplicate and collocated carbonyl
compound samples as the CV per pollutant per site, the average CV per site, the average CV per
pollutant, and the overall average CV for NMP sites sampling carbonyl compounds. The
duplicate and collocated sample results show low- to mid-level variability among the sites,
ranging from a CV of 0.86 percent (formaldehyde for MWOK) to 49.32 percent (tolualdehydes
for UCSD). The pollutant-specific average CV ranged from 3.32 percent (acetaldehyde) to
17.74 percent (tolualdehydes). The site-specific average CV ranged from 3.92 percent for OCOK
to 11.59 percent for UCSD. The average CV for every site is less than the program MQO of
15 percent. The overall average method precision was 6.83 percent for carbonyl compounds.
Table 29-4. Carbonyl Compound Method Precision: Coefficient of Variation Based on
Duplicate and Collocated Samples by Site
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes
Valeraldehyde
Average by Site
AZFL
3.62
7.03
7.14
5.31
2.61
NA
6.28
7.19
NA
2.80
18.13
8.91
6.90
BTUT
2.30
3.53
4.88
4.24
1.66
NA
5.64
8.15
NA
2.60
26.30
4.69
6.40
CHNJ
2.41
6.37
7.46
3.91
3.53
NA
3.58
4.18
NA
4.88
9.49
1.35
4.71
DEMI
10.13
4.57
9.12
12.76
16.58
NA
11.67
11.00
NA
8.35
9.93
9.91
10.40
ELNJ
1.80
10.82
3.76
5.64
5.88
NA
2.37
10.39
NA
2.12
22.21
4.24
6.92
GLKY
3.13
5.96
7.66
4.23
5.94
NA
2.51
2.86
NA
3.31
8.90
8.93
5.34
GPCO
2.08
6.34
5.34
4.50
3.90
NA
2.21
7.69
NA
3.17
36.57
6.23
7.81
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29-17
-------
Table 29-4. Carbonyl Compound Method Precision: Coefficient of Variation Based on
Duplicate and Collocated Samples by Site (Continued)
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes
Valeraldehyde
Average by Site
INDEM
7.65
9.23
9.96
5.81
7.15
NA
9.55
8.68
NA
6.45
8.34
7.96
8.08
MWOK
1.82
10.78
6.04
6.34
2.69
NA
0.86
9.20
NA
4.35
7.02
8.58
5.77
NBIL
2.25
7.49
5.91
6.91
4.20
NA
2.89
7.62
NA
2.01
10.32
5.03
5.46
NBNJ
8.57
4.76
6.51
7.64
5.94
NA
6.50
10.72
NA
7.01
37.94
8.47
10.41
OCOK
1.57
4.83
4.81
1.62
3.64
NA
1.90
5.70
NA
1.45
9.41
4.24
3.92
ORFL
7.19
16.62
7.14
7.98
7.71
NA
3.79
10.05
NA
4.57
36.96
6.31
10.83
PROK
1.17
2.80
9.12
4.79
2.66
NA
2.16
4.90
NA
3.16
6.87
6.60
4.42
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
Table 29-4. Carbonyl Compound Method Precision: Coefficient of Variation Based on
Duplicate and Collocated Samples by Site (Continued)
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes
Valeraldehyde
Average by Site
PXSS
2.64
4.43
3.61
3.21
3.08
NA
5.82
5.77
NA
3.36
9.46
8.30
4.97
S4MO
1.39
3.46
4.98
3.92
3.70
NA
3.19
7.36
NA
4.18
24.50
6.71
6.34
SEWA
1.84
1.89
12.41
3.58
7.54
NA
3.96
6.38
NA
4.66
8.85
3.75
5.49
SKFL
2.58
8.69
8.15
8.18
6.83
NA
2.64
8.05
NA
2.83
37.07
5.44
9.05
SPIL
1.74
8.10
4.10
4.16
8.10
NA
3.21
5.65
NA
1.89
9.41
4.43
5.08
SSSD
4.41
18.22
7.03
6.01
3.97
NA
8.29
9.06
NA
5.37
11.33
7.00
8.07
SYFL
2.07
7.56
9.07
4.13
4.81
NA
2.81
7.37
NA
3.07
13.73
6.94
6.16
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29-18
-------
Table 29-4. Carbonyl Compound Method Precision: Coefficient of Variation Based on
Duplicate and Collocated Samples by Site (Continued)
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes
Valeraldehyde
Average by Site
TMOK
2.02
4.21
3.10
3.64
2.51
NA
1.79
6.17
NA
4.23
9.70
3.17
4.05
TOOK
1.89
1.60
7.85
3.42
3.08
NA
1.02
7.03
NA
2.33
7.05
6.77
4.20
UCSD
2.25
12.68
6.53
7.15
7.50
NA
6.62
12.55
NA
5.03
49.32
6.23
11.59
WPIN
4.61
8.63
5.24
6.79
10.05
NA
4.93
11.31
NA
5.89
14.72
11.20
8.34
# of Pairs
158
158
157
157
153
0
158
157
0
158
131
153
~
Average by
Pollutant
3.32
7.22
6.68
5.43
5.41
NA
4.25
7.80
NA
3.96
17.74
6.46
6.83
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method
is calculated from the site-specific averages and provided in the final column of the table.
29.2.4 PAH Method Precision
The method precision results for collocated PAH samples are shown in Table 29-5 as the
CV per pollutant per site, the average CV per site, the average CV per pollutant, and the overall
average CV for NMP sites sampling PAHs. All samples evaluated in this section are collocated
samples. Collocated systems were the responsibility of the participating agency for sites
sampling PAHs. Thus, collocated samples were not collected at most PAH sites because few
sites had collocated samplers. Therefore, the method precision data for PAHs is based on only
five sites for 2011.
The results from collocated samples show low- to mid-level variability among sites,
ranging from a CV of 0.38 percent (benzo(a)anthracene for SDGA) to 58.36 percent (anthracene
for DEMI). The pollutant-specific average CV ranged from 1.65 percent (cyclopenta[cd]pyrene)
to 21.17 percent (anthracene). The site-specific average CV ranged from 5.98 percent for SEWA
to 19.42 percent for RUCA. The overall average method precision was 11.83 percent.
29-19
-------
Table 29-5. PAH Method Precision: Coefficient of Variation Based on Collocated Samples
by Site
Pollutant
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Coronene
Cyclopenta|cd|pyrene
Dibenz(a,h)anthracene
Fluoranthene
Fluorene
9-Fluorenone
Indeno(l,2,3-cd)pyrene
Naphthalene
Perylene
Phenanthrene
Pyrene
Retene
Average by Site
DEMI
7.47
10.29
58.36
49.45
4.36
6.24
6.42
7.69
7.00
7.29
2.51
NA
NA
4.61
5.13
4.84
7.02
8.59
NA
5.77
5.60
20.10
12.04
RUCA
26.38
33.31
6.32
NA
NA
13.93
6.74
10.06
NA
8.38
NA
NA
NA
24.59
24.32
26.96
NA
15.49
NA
28.02
27.07
20.28
19.42
SDGA
10.45
11.41
7.12
0.38
5.22
5.09
9.00
11.21
1.75
15.48
NA
1.09
NA
5.91
7.88
6.12
17.93
6.41
NA
8.33
19.90
16.60
8.80
SEWA
7.16
8.82
12.89
3.70
12.66
6.38
1.12
0.41
5.32
7.25
1.92
2.20
NA
5.33
6.69
6.81
2.23
5.98
NA
5.47
7.44
9.75
5.98
SYFL
11.42
13.02
NA
9.82
13.78
15.29
19.75
15.67
9.63
10.43
1.00
NA
NA
12.67
11.82
13.26
13.14
15.27
NA
11.79
13.39
21.07
12.90
#of
Pairs
29
11
13
8
7
23
16
14
8
27
o
J
2
0
29
29
29
12
29
0
29
29
28
~
Average by
Pollutant
12.58
15.37
21.17
15.84
9.00
9.38
8.61
9.01
5.92
9.77
1.81
1.65
NA
10.62
11.17
11.60
10.08
10.34
NA
11.88
14.68
17.56
11.83
NA=No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29.2.5 Metals Method Precision
The method precision for all collocated metals samples are presented in Table 29-6 as the
CV per pollutant per site, the average CV per site, the average CV per pollutant, and the overall
average CV for NMP sites sampling metals. All samples evaluated in this section are collocated
samples. The results from collocated samples show low- to mid-level variability among sites,
ranging from a CV of 0 percent (nickel for UNVT and beryllium for GLKY) to 45.18 percent
(mercury for UNVT). The pollutant-specific average CV ranged from 5.16 percent (chromium)
29-20
-------
to 26.44 percent (mercury). The site-specific average CV ranged from 8.70 percent for BOMA to
20.84 percent for GLKY. The overall average method precision for metals was 13.58 percent.
Table 29-6. Metals Method Precision: Coefficient of Variation Based on Collocated
Samples by Site
Pollutant
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Cobalt
Lead
Manganese
Mercury
Nickel
Selenium
Average by Site
BOMA
3.26
4.06
18.02
18.07
5.43
12.25
6.43
3.69
15.22
4.89
4.37
8.70
BTUT
6.79
11.01
11.11
15.67
NA
15.02
13.09
10.38
20.20
3.13
18.57
12.50
GLKY
19.08
21.90
0.00
20.56
NA
31.64
14.99
16.15
27.65
43.46
12.99
20.84
S4MO
5.48
11.80
22.00
8.64
2.13
18.74
5.13
5.46
36.97
43.24
10.10
15.43
TOOK
8.86
5.95
7.47
17.90
7.93
14.56
7.85
8.28
13.45
9.07
5.23
9.69
UNVT
9.05
23.20
NA
16.15
NA
NA
4.55
4.16
45.18
0.00
12.34
14.33
#of
Pairs
169
158
74
168
66
156
169
169
115
99
163
~
Average by
Pollutant
8.75
12.99
11.72
16.17
5.16
18.44
8.67
8.02
26.44
17.30
10.60
13.58
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29.2.6 Hexavalent Chromium Method Precision
Table 29-7 presents the method precision results from collocated hexavalent chromium
samples as the CV per site and the overall average CV for NMP sites sampling hexavalent
chromium. All samples evaluated in this section are collocated samples. Hexavalent chromium is
a NATTS MQO Core Analyte and the sites shown in Table 29-6 are collocated NATTS sites.
The site-specific CV ranged from 6.04 percent for SYFL to 31.21 percent for PXSS, with an
overall average method precision of 14.54 percent.
29-21
-------
Table 29-7. Hexavalent Chromium Method Precision: Coefficient of Variation Based on
Collocated Samples by Site
Site
BOMA
BTUT
CAMS 35
CHSC
DEMI
GLKY
GPCO
HOW
MONY
NBIL
PRRI
PXSS
RIVA
ROCH
S4MO
SDGA
SEWA
SKFL
SYFL
UNVT
WADC
# of Pairs
Average by Site
Average CV
27.62
22.35
10.97
8.86
10.93
20.41
10.91
9.10
8.25
18.21
17.14
31.21
11.46
19.56
7.86
16.80
11.03
10.80
6.04
15.45
10.31
110
14.54
BOLD ITALICS = EPA-de signaled
NATTS Site
Orange shading indicates the average CV
for this method
29-22
-------
29.3 Analytical Precision
Analytical precision is a measurement of random errors associated with the process of
analyzing environmental samples. These errors may result from various factors, including
random "noise" inherent to analytical instruments. Laboratories can evaluate the analytical
precision of ambient air samples by comparing concentrations measured during multiple
analyses of a single sample (i.e., replicate samples). CVs were calculated for every replicate
analysis run on duplicate or collocated samples collected during the program year. However,
only results at or above the MDL were used in these calculations, similar to the calculation of
method precision discussed in Section 29.2.
Table 29-8 presents the 2011 NMP analytical precision for VOCs, SNMOCs, carbonyl
compounds, PAHs, metals, and hexavalent chromium, presented as average CV (expressed as a
percentage). The analytical precision averaged across all sites collecting duplicate or collocated
samples met the program MQO, which is 15 percent CV. The analytical precision for all six
methods was less than 8 percent. This table also includes the number of pairs that were included
in the calculation of the analytical precision. The number of pairs including those with
concentrations less than the MDL is also included in Table 29-8 to provide an indication of the
effect that excluding those with concentrations less than the MDL has on the population of pairs
in the dataset.
Table 29-8. Analytical Precision by Analytical Method
Method/Pollutant
Group
voc
(TO-15)
SNMOC
Carbonyl Compounds
(TO-11A)
PAH
(TO-13)
Metals Analysis
(Method IO-3. 5)
Hexavalent Chromium
(EPA-approved method)
MQO
Average
Coefficient of
Variation
(%)
6.60
7.39
2.43
4.61
7.91
6.69
Number of
Pairs Included
in the
Calculation
6,174
2,437
3,178
761
3,074
223
Total Number of
Pairs Without
the > MDL
exclusion
7,397
3,059
3,178
941
3,721
225
15. 00 percent CV
29-23
-------
Tables 29-9 through 29-14 present analytical precision for VOCs, SNMOCs, carbonyl
compounds, PAHs, metals, hexavalent chromium, respectively, as the CV per pollutant per site,
and the average CV per pollutant, per site, and per method. Pollutants exceeding the 15 percent
MQO for CV are bolded in each table. In Tables 29-9 through 29-14, the number of pairs in
comparison to the respective tables listed for duplicate or collocated analyses in Tables 29-2
through 29-7, is approximately twice as high because each sample produces a replicate for each
duplicate (or collocated) sample. The replicate analyses of both duplicate and collocated samples
indicate that the analytical precision level is within the program MQOs. The shaded rows in each
table identify the NATTS MQO Core Analytes for each method.
29.3.1 VOC Analytical Precision
Table 29-9 presents analytical precision results from replicate analyses of all duplicate
and collocated VOC samples as the CV per pollutant per site, the average CV per site, the
average CV per pollutant, and the overall average CV for NMP sites sampling VOCs. The
analytical precision results from replicate analyses of all duplicate and collocated samples show
that, for most of the pollutants, the VOC analytical precision was within the program MQO of
15 percent. The CV ranged from 0 percent for several pollutants and several sites to
26.61 percent (methyl isobutyl ketone for TMOK). The pollutant-specific average CV ranged
from 3.01 percent (1,1,1-trichloroethane) to 20.47 percent (ฃrami-l,2-dichloroethylene). Note that
in these cases, the number of pairs included in the calculations are low. The site-specific average
CV ranged from 4.31 percent for GPCO to 9.18 percent for PROK. The overall average
analytical precision was 6.60 percent.
29-24
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1 ,2-Dibromoethane
m -Dichlorobenzene
o-Dichlorobenzene
^-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
c/s-l,2-Dichloroethylene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 ,3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Aery late
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
BTUT
7.75
NA
NA
5.24
NA
NA
NA
7.47
9.42
5.85
5.84
NA
6.07
12.57
5.49
NA
NA
NA
NA
NA
NA
NA
5.35
NA
10.09
0.00
NA
20.47
6.59
NA
NA
NA
11.21
NA
NA
6.00
NA
NA
6.75
NA
BURVT
3.60
5.41
NA
5.04
NA
NA
NA
10.34
5.44
NA
4.78
NA
14.36
11.04
3.48
NA
NA
NA
NA
NA
NA
NA
3.48
NA
9.97
NA
NA
NA
4.56
NA
NA
NA
8.12
NA
NA
7.07
NA
NA
7.36
NA
CHNJ
6.21
4.62
NA
6.01
NA
NA
NA
15.71
18.58
6.62
6.43
NA
10.45
12.04
6.39
NA
NA
NA
NA
NA
NA
NA
6.19
NA
8.45
NA
NA
NA
7.18
NA
NA
NA
12.42
NA
NA
8.17
NA
NA
11.54
8.95
DEMI
4.03
NA
NA
6.45
NA
NA
NA
10.83
7.56
4.03
6.31
NA
3.02
6.04
5.81
NA
NA
NA
NA
NA
NA
NA
5.79
NA
5.56
NA
NA
NA
4.78
NA
NA
NA
12.67
NA
NA
7.53
NA
NA
10.41
NA
ELNJ
5.26
8.88
NA
5.27
NA
NA
NA
11.50
6.20
4.58
6.70
NA
0.00
5.43
4.78
NA
NA
NA
NA
NA
NA
2.70
4.73
NA
1.89
NA
NA
NA
5.13
NA
NA
NA
6.96
NA
NA
5.72
NA
NA
16.20
4.47
GLKY
5.35
4.42
NA
6.69
NA
NA
NA
12.27
6.44
6.04
6.56
9.43
NA
6.81
4.47
NA
NA
NA
NA
NA
NA
NA
4.85
13.69
6.18
NA
NA
NA
4.70
NA
NA
NA
8.94
NA
NA
6.74
NA
NA
9.94
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29-25
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Methyl fer/-Butyl Ether
w-Octane
Propylene
Styrene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1 , 1 ,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1,3,5 -Trimethy Ibenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
BTUT
NA
5.42
5.60
8.43
NA
4.70
4.71
NA
NA
NA
NA
5.94
8.30
6.47
8.20
NA
5.06
6.16
7.18
BURVT
NA
11.93
4.30
13.45
NA
7.19
4.27
NA
NA
NA
NA
3.66
6.33
8.55
6.14
NA
6.13
7.53
7.06
CHNJ
NA
7.34
5.25
7.49
NA
16.63
6.30
NA
NA
NA
NA
6.29
7.00
8.45
8.93
NA
8.68
16.21
9.09
DEMI
NA
16.65
5.55
9.26
NA
5.16
4.98
NA
NA
NA
NA
5.39
6.49
6.54
5.27
NA
6.60
9.83
7.02
ELNJ
5.61
7.36
4.96
12.02
NA
7.91
4.38
NA
NA
NA
NA
4.19
5.37
8.01
11.14
NA
5.46
8.99
6.39
GLKY
9.12
6.98
5.82
6.66
NA
NA
5.16
NA
NA
NA
NA
4.60
5.45
7.78
13.26
20.20
7.21
7.46
7.70
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29-26
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1 ,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethylene
/raซ5-l,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 , 3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Aery late
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
GPCO
3.50
4.22
NA
4.55
NA
NA
NA
6.93
3.22
3.54
4.86
NA
3.62
4.88
3.58
NA
NA
NA
NA
NA
NA
NA
3.31
NA
1.96
NA
NA
NA
6.72
NA
NA
NA
3.24
NA
NA
3.27
NA
NA
5.31
9.03
MWOK
5.05
9.75
NA
4.71
NA
NA
NA
6.30
6.56
1.95
5.29
NA
5.24
7.36
2.50
NA
NA
NA
NA
NA
NA
3.82
2.50
NA
6.46
NA
NA
NA
4.13
NA
NA
NA
5.41
NA
NA
4.39
NA
NA
3.82
NA
NBIL
5.67
4.78
NA
5.78
NA
6.52
7.71
10.23
4.60
3.92
9.48
NA
8.77
4.02
3.89
NA
NA
3.98
NA
NA
NA
NA
3.94
NA
9.66
NA
NA
NA
6.39
NA
NA
NA
4.65
NA
NA
3.75
NA
NA
10.20
NA
NBNJ
5.23
3.71
NA
4.62
NA
NA
NA
7.47
3.89
4.58
5.01
NA
1.37
7.06
4.30
NA
NA
NA
NA
NA
NA
NA
4.28
NA
5.74
6.15
NA
NA
3.71
NA
NA
NA
6.51
NA
7.44
4.70
NA
NA
6.23
NA
OCOK
3.30
NA
NA
5.58
NA
NA
NA
11.91
8.45
NA
7.01
NA
NA
3.23
2.58
NA
NA
NA
NA
NA
NA
NA
2.56
NA
NA
NA
NA
NA
6.31
NA
NA
NA
7.82
NA
NA
7.13
NA
NA
8.32
NA
PANJ
4.45
NA
NA
5.93
NA
NA
NA
3.23
5.28
NA
6.55
NA
5.30
3.54
4.94
NA
NA
NA
NA
NA
NA
5.77
4.91
NA
5.92
NA
NA
NA
4.72
NA
NA
NA
6.98
NA
NA
4.67
NA
NA
3.69
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29-27
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Methyl fer/-Butyl Ether
w-Octane
Propylene
Styrene
1, 1,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1 , 1 ,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
GPCO
NA
5.08
4.41
3.42
NA
4.66
3.30
NA
NA
NA
4.98
3.70
5.33
3.55
4.19
NA
3.62
3.11
4.31
MWOK
NA
4.29
2.48
7.82
NA
5.64
3.32
NA
NA
NA
NA
2.88
4.40
7.72
6.25
NA
4.29
7.58
5.07
NBIL
NA
6.63
3.98
6.94
NA
6.11
3.92
NA
NA
NA
NA
3.51
3.55
4.43
6.43
NA
4.13
4.34
5.73
NBNJ
3.92
6.98
4.16
7.33
NA
6.71
4.47
NA
NA
NA
NA
4.37
4.18
6.45
8.77
11.79
5.02
6.16
5.56
OCOK
NA
8.75
3.25
13.70
NA
8.78
4.51
NA
NA
NA
NA
3.13
7.29
10.05
9.84
NA
7.51
13.46
7.15
PANJ
NA
5.07
4.82
3.61
NA
6.47
5.92
NA
3.01
NA
NA
5.41
4.75
5.61
4.58
8.32
5.16
5.30
5.14
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29-28
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethylene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1, 3-D ichloropropene
trans- 1 ,3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Aery late
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 , 3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
PROK
8.28
4.91
NA
7.12
NA
NA
NA
8.25
7.03
NA
7.32
NA
9.41
NA
6.35
NA
NA
NA
NA
NA
NA
9.09
6.28
NA
10.23
NA
NA
NA
6.97
NA
NA
NA
9.05
NA
NA
11.11
NA
NA
7.70
NA
PXSS
4.96
2.76
NA
6.60
NA
NA
NA
8.87
5.24
6.52
6.66
NA
7.44
4.86
4.63
NA
NA
NA
NA
NA
NA
6.24
4.58
NA
5.25
NA
NA
NA
6.98
NA
NA
NA
7.44
NA
NA
4.67
NA
NA
9.51
NA
S4MO
4.71
NA
NA
5.10
NA
NA
NA
16.11
7.20
4.14
4.87
NA
3.70
8.05
4.72
NA
NA
NA
NA
NA
NA
4.24
4.59
NA
9.95
NA
NA
NA
4.37
NA
NA
NA
9.52
NA
NA
5.44
NA
NA
6.43
NA
SEWA
3.16
7.97
NA
3.10
NA
NA
NA
12.78
7.36
NA
4.56
NA
0.00
8.37
3.36
NA
NA
NA
NA
NA
NA
NA
3.16
NA
2.86
NA
NA
NA
3.15
NA
NA
NA
5.29
NA
NA
4.09
NA
NA
9.22
NA
SPIL
4.92
5.79
NA
7.08
NA
NA
NA
7.88
5.53
4.68
6.55
NA
14.17
6.73
5.16
NA
NA
NA
NA
NA
NA
NA
5.28
NA
12.20
NA
NA
NA
5.04
NA
NA
NA
8.21
NA
NA
8.88
NA
NA
6.39
NA
SSSD
4.88
13.24
NA
4.24
NA
NA
NA
7.20
8.44
1.79
3.86
NA
9.75
8.03
4.05
NA
NA
NA
NA
NA
NA
NA
3.83
NA
8.52
NA
NA
NA
5.06
NA
NA
NA
7.43
NA
NA
5.00
NA
NA
7.74
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29-29
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Methyl ferMSutyl Ether
w-Octane
Propylene
Styrene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1, 1,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1,3,5 -Trimethy Ibenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
PROK
NA
17.76
7.19
15.25
NA
NA
6.72
NA
NA
NA
NA
6.26
7.05
15.67
NA
NA
10.68
14.60
9.18
PXSS
NA
6.26
4.51
9.23
NA
4.84
4.29
NA
NA
NA
NA
4.08
6.55
5.45
6.17
NA
4.70
5.35
5.88
S4MO
NA
6.00
5.14
15.26
NA
8.96
4.11
NA
NA
NA
NA
3.89
7.03
11.27
19.15
6.79
5.00
7.03
7.24
SEWA
NA
11.33
5.69
8.36
NA
8.75
1.98
NA
NA
NA
0.00
2.51
4.90
6.59
7.44
NA
3.45
9.82
5.53
SPIL
NA
10.49
5.86
10.66
NA
6.86
5.94
NA
NA
NA
6.52
4.58
5.23
11.48
10.28
NA
8.08
10.72
7.54
SSSD
7.58
6.46
4.37
5.93
NA
8.52
3.77
NA
NA
NA
NA
3.14
5.78
5.76
5.33
NA
5.26
5.30
6.08
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29-30
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Acetylene
Acrylonitrile
tert-Amyl Methyl Ether
Benzene
Bromochloromethane
Bromodichloromethane
Bromoform
Bromomethane
1,3 -Butadiene
Carbon Bisulfide
Carbon Tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
Chloromethylbenzene
Chloroprene
Dibromochloromethane
1 ,2-Dibromoethane
/w-Dichlorobenzene
o-Dichlorobenzene
ฃ>-Dichlorobenzene
Dichlorodifluoromethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethene
cis- 1 ,2-Dichloroethylene
trans- 1 ,2-Dichloroethylene
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 ,3 -Dichloropropene
Dichlorotetrafluoroethane
Ethyl Acrylate
Ethyl tert-Butyl Ether
Ethylbenzene
Hexachloro- 1 ,3 -butadiene
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Methyl Methacrylate
TMOK
2.97
14.40
NA
5.05
NA
NA
NA
8.19
5.37
2.90
5.55
NA
5.06
2.33
3.32
NA
NA
NA
NA
NA
NA
6.12
3.17
NA
1.82
NA
NA
NA
5.18
NA
NA
NA
5.92
NA
NA
4.24
NA
NA
26.61
NA
TOOK
5.88
NA
NA
7.32
NA
NA
NA
8.92
6.59
0.44
6.82
NA
7.19
2.27
5.72
NA
NA
NA
NA
NA
NA
4.23
5.93
NA
3.62
NA
NA
NA
5.18
NA
NA
NA
6.54
NA
NA
6.68
NA
NA
7.80
NA
UCSD
6.80
4.34
NA
6.81
NA
NA
NA
5.79
9.60
3.14
6.49
NA
6.30
12.24
5.78
NA
NA
NA
NA
NA
NA
NA
5.90
NA
8.58
NA
NA
NA
5.17
NA
NA
NA
6.45
NA
NA
5.08
NA
NA
6.99
NA
#of
Pairs
283
45
0
283
0
12
2
191
249
129
282
1
50
144
283
0
0
11
0
0
0
29
283
1
69
o
6
0
2
277
0
0
0
280
0
1
281
0
0
216
4
Average
by
Pollutant
5.05
6.61
NA
5.63
NA
6.52
7.71
9.44
7.05
4.05
6.07
9.43
6.38
6.84
4.54
NA
NA
3.98
NA
NA
NA
5.28
4.51
13.69
6.75
3.07
NA
20.47
5.33
NA
NA
NA
7.66
NA
7.44
5.92
NA
NA
8.96
7.48
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29-31
-------
Table 29-9. VOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Methyl tert-Butyl Ether
w-Octane
Propylene
Styrene
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Toluene
1 ,2,4-Trichlorobenzene
1,1,1 -Trichloroethane
1 , 1 ,2-Trichloroethane
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
Vinyl chloride
m,p-Xylene
o-Xylene
Average by Site
TMOK
NA
6.16
3.70
12.46
NA
9.05
4.24
NA
NA
NA
NA
3.00
7.23
5.15
7.96
NA
4.07
14.70
6.64
TOOK
NA
6.91
5.41
9.43
NA
9.64
6.33
NA
NA
NA
NA
6.76
5.40
5.60
6.42
NA
6.69
6.83
6.17
UCSD
NA
10.60
5.37
5.25
NA
9.01
4.62
NA
NA
NA
5.44
5.20
4.83
8.74
NA
16.85
5.59
7.50
6.95
#of
Pairs
12
278
283
241
0
129
283
0
1
0
10
282
283
262
141
8
277
273
-
Average
by
Pollutant
6.56
8.31
4.85
9.14
NA
7.66
4.63
NA
3.01
NA
4.24
4.40
5.83
7.59
8.20
12.79
5.83
8.48
6.60
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29.3.2 SNMOC Analytical Precision
Table 29-10 presents analytical precision results from replicate analyses of all duplicate
and collocated SNMOC samples as the CV per pollutant per site, the average CV per site, the
average CV per pollutant, and the overall average CV for NMP sites sampling SNMOCs. The
CV ranged from 0 percent (2-methyl-2-butene for BMCO) to 43.71 percent (1-dodecene for
NBIL). The pollutant-specific average CV ranged from 0.37 percent (1-hexene) to 18.93 percent
(1-dodecene). The site-specific average CV ranged from 4.47 percent for PACO to 16.14 percent
for BMCO. The overall program average CV was 7.39 percent.
29-32
-------
Table 29-10. SNMOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site
Pollutant
Acetylene
Benzene
1,3 -Butadiene
w-Butane
c/s-2-Butene
trans-2-Butene
Cyclohexane
Cyclopentane
Cyclopentene
w-Decane
1-Decene
w-Diethylbenzene
p-Diethylbenzene
2,2-Dimethylbutane
2,3 -Dimethylbutane
2,3 -Dimethylpentane
2,4-Dimethylpentane
w-Dodecane
1-Dodecene
Ethane
2-Ethyl-l-butene
Ethylbenzene
Ethylene
OT-Ethyltoluene
o-Ethyltoluene
p-Ethyltoluene
w-Heptane
1-Heptene
w-Hexane
1-Hexene
c/s-2-Hexene
trans-2-Hexene
Isobutane
Isobutene/ 1 -Butene
Isopentane
Isoprene
Isopropylbenzene
2-Methyl- 1 -butene
3 -Methyl- 1 -butene
BMCO
15.60
19.92
NA
NA
1.14
6.91
19.11
11.11
2.99
18.02
NA
5.85
20.70
16.09
NA
NA
15.39
14.08
36.60
19.42
NA
17.66
10.91
4.25
NA
8.91
18.74
23.95
20.94
NA
NA
NA
20.27
NA
19.00
NA
NA
20.20
NA
BTUT
23.90
3.83
8.51
1.10
7.38
4.51
5.12
5.20
12.75
4.52
NA
9.43
15.21
7.80
8.96
5.99
8.63
3.23
5.82
25.25
NA
7.32
28.33
3.63
8.83
8.57
2.59
NA
2.99
0.56
NA
NA
1.37
14.23
1.90
2.61
NA
8.43
NA
NBIL
2.64
3.97
NA
1.53
NA
5.97
12.13
11.78
2.46
6.37
2.40
6.63
16.02
7.09
2.82
6.57
4.85
9.99
43.71
0.46
NA
5.22
1.98
6.33
15.29
10.04
6.14
NA
3.42
NA
NA
NA
1.89
4.74
1.78
1.88
2.22
NA
NA
PACO
3.66
2.16
NA
1.13
3.44
3.86
3.90
6.87
10.74
2.50
NA
4.76
7.87
7.83
1.56
2.84
3.84
6.74
0.62
0.86
NA
4.61
1.50
2.19
6.87
5.63
1.78
1.75
2.80
0.19
NA
NA
1.09
6.61
5.68
16.23
4.84
NA
NA
RICO
2.07
2.44
4.22
0.35
12.46
2.55
1.37
3.29
11.70
5.77
NA
9.48
4.52
8.00
6.24
7.78
9.49
8.71
7.18
0.45
NA
7.79
1.24
7.03
11.81
7.41
2.63
3.13
0.77
NA
NA
NA
1.06
NA
1.63
5.50
NA
3.43
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29-33
-------
Table 29-10. SNMOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
2-Methyl- 1 -pentene
4-Methyl- 1 -pentene
2-Methyl-2-butene
Methylcyclohexane
Methylcyclopentane
2-Methylheptane
3-Methylheptane
2-Methylhexane
3 -Methy Ihexane
2-Methylpentane
3-Methylpentane
w-Nonane
1-Nonene
w-Octane
1-Octene
w-Pentane
1 -Pentene
c/s-2-Pentene
trans-2-Pentene
a-Pinene
&-Pinene
Propane
w-Propylbenzene
Propylene
Propyne
Styrene
Toluene
w-Tridecane
1-Tridecene
1 ,2,3 -Trimethylbenzene
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
2,2,3 -Trimethylpentane
2,2,4-Trimethylpentane
2,3 ,4-Trimethylpentane
w-Undecane
1-Undecene
w-Xylene/^-Xylene
o-Xylene
Average by Site
BMCO
NA
NA
0.00
21.56
21.32
19.29
25.42
22.60
23.73
18.00
19.62
21.86
NA
24.58
NA
20.42
23.91
NA
2.56
NA
NA
19.12
NA
15.48
NA
NA
19.07
NA
NA
8.06
14.19
0.43
NA
NA
18.58
16.17
NA
NA
11.14
16.14
BTUT
NA
NA
4.56
4.73
4.08
11.13
6.69
3.54
7.75
4.42
4.68
6.37
NA
5.45
2.75
3.06
5.25
NA
6.90
13.09
2.36
0.30
5.50
6.48
NA
10.46
1.91
7.54
NA
12.73
5.51
6.43
6.02
10.51
5.16
9.98
2.93
4.47
7.09
7.05
NBIL
NA
NA
9.79
13.26
3.35
17.65
7.49
14.42
9.87
3.88
6.74
5.84
13.51
6.69
NA
2.49
7.64
NA
11.96
3.39
NA
0.36
20.84
4.19
8.74
8.20
3.26
NA
NA
16.22
8.35
7.87
4.72
13.08
10.66
6.72
1.32
3.71
4.92
7.57
PACO
NA
NA
7.82
1.79
1.70
1.86
3.84
1.84
7.34
5.51
1.53
1.76
5.72
5.15
4.61
2.18
15.59
NA
21.16
NA
NA
0.78
5.38
2.15
NA
NA
1.64
NA
NA
7.09
1.97
7.66
4.94
1.20
6.24
3.44
2.60
2.57
3.07
4.47
RICO
NA
NA
4.62
0.99
0.56
4.64
4.92
5.47
2.39
0.38
1.60
7.08
NA
3.74
NA
0.70
6.40
5.92
4.63
4.86
NA
0.25
11.34
1.24
NA
NA
4.14
NA
NA
10.18
4.87
5.39
NA
15.81
5.16
11.98
NA
1.64
6.11
5.06
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29-34
-------
Table 29-10. SNMOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
Acetylene
Benzene
1,3 -Butadiene
w-Butane
c/s-2-Butene
/raws-2-Butene
Cyclohexane
Cyclopentane
Cyclopentene
w-Decane
1-Decene
/w-Diethylbenzene
ฃ>-Diethylbenzene
2,2-Dimethylbutane
2,3 -Dimethylbutane
2,3 -Dimethylpentane
2,4-Dimethylpentane
w-Dodecane
1-Dodecene
Ethane
2-Ethyl-l-butene
Ethylbenzene
Ethylene
/w-Ethyltoluene
o-Ethyltoluene
ฃ>-Ethyltoluene
w-Heptane
1-Heptene
w-Hexane
1-Hexene
c/s-2-Hexene
/raซs-2-Hexene
Isobutane
Isobutene/ 1 -Butene
Isopentane
Isoprene
Isopropylbenzene
2-Methyl-l-butene
3-Methyl-l-butene
SSSD
3.86
3.30
NA
2.55
3.90
8.64
3.71
7.13
NA
2.78
NA
6.21
10.71
11.47
7.92
1.79
6.67
4.32
21.25
1.24
NA
10.83
1.24
5.43
1.35
4.70
4.35
NA
5.63
NA
4.76
NA
1.98
5.06
5.76
3.72
NA
7.81
NA
UCSD
5.21
4.23
NA
2.52
NA
6.56
3.23
5.55
NA
NA
NA
5.22
16.08
8.22
4.50
NA
NA
1.77
17.31
0.85
NA
7.70
2.39
NA
NA
NA
3.35
NA
4.83
NA
NA
NA
2.67
1.56
2.46
6.70
NA
3.16
NA
#of
Pairs
61
60
7
40
19
31
45
49
9
38
2
52
45
52
32
32
34
38
18
61
0
53
61
38
29
22
44
8
60
2
1
0
61
26
58
31
2
22
0
Average by
Pollutant
8.13
5.69
6.36
1.53
5.66
5.57
6.94
7.28
8.13
6.66
2.40
6.80
13.01
9.50
5.33
4.99
8.14
6.98
18.93
6.93
NA
8.73
6.80
4.81
8.83
7.54
5.65
9.61
5.91
0.37
4.76
NA
4.33
6.44
5.46
6.11
3.53
8.61
NA
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29-35
-------
Table 29-10. SNMOC Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site (Continued)
Pollutant
2-Methyl- 1 -pentene
4-Methyl- 1 -pentene
2-Methyl-2-butene
Methylcyclohexane
Methylcyclopentane
2-Methylheptane
3-Methylheptane
2-Methylhexane
3-Methylhexane
2-Methylpentane
3-Methylpentane
w-Nonane
1-Nonene
w-Octane
1-Octene
w-Pentane
1 -Pentene
c/s-2-Pentene
/raws-2-Pentene
a-Pinene
6-Pinene
Propane
w-Propylbenzene
Propylene
Propyne
Styrene
Toluene
w-Tridecane
1-Tridecene
1 ,2,3 -Trimethylbenzene
1 ,2,4-Trimethylbenzene
1 ,3 ,5-Trimethylbenzene
2,2,3 -Trimethylpentane
2,2,4-Trimethylpentane
2,3 ,4-Trimethylpentane
w-Undecane
1-Undecene
7w-Xylene//?-Xylene
o-Xylene
Average by Site
SSSD
NA
NA
3.73
5.95
4.26
7.00
5.76
3.40
8.78
5.64
4.20
2.75
NA
3.15
NA
2.67
13.10
NA
7.35
4.82
NA
0.87
1.01
2.89
NA
2.35
5.11
NA
NA
5.71
5.62
5.56
NA
5.34
7.42
6.89
NA
2.48
5.26
5.33
UCSD
NA
AN
2.49
1.55
4.71
NA
NA
4.25
16.23
4.59
5.77
NA
NA
2.38
NA
6.47
18.65
NA
NA
NA
NA
0.82
NA
3.53
NA
0.36
2.61
NA
NA
22.52
7.86
NA
NA
4.62
NA
6.70
6.73
10.57
11.62
6.07
#of
Pairs
0
0
27
45
57
26
27
54
54
61
58
37
7
40
o
6
61
46
3
34
12
o
J
61
15
61
2
6
59
4
0
32
55
25
9
49
36
38
8
30
49
~
Average by
Pollutant
NA
NA
4.72
7.12
5.71
10.26
9.02
7.93
10.87
6.06
6.31
7.61
9.62
7.31
3.68
5.43
12.94
5.92
9.09
6.54
2.36
3.22
8.81
5.14
8.74
5.34
5.39
7.54
NA
11.79
6.91
5.56
5.23
8.43
8.87
8.84
3.40
4.24
7.03
7.39
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Orange shading indicates the site-specific average CV for this method; the overall average CV for
this method is calculated from the site-specific averages and provided in the final column of the table.
29-36
-------
29.3.3 Carbonyl Compound Analytical Precision
Table 29-11 presents the analytical precision results from replicate analyses of duplicate
and collocated carbonyl compound samples as the CV per pollutant per site, the average CV per
site, the average CV per pollutant, and the overall average CV for NMP sites sampling carbonyl
compounds. The overall average variability was 2.43 percent, which is well within the program
MQO of 15 percent CV. The analytical precision results from replicate analyses of duplicate and
collocated samples range from 0.25 percent (acetaldehyde for CHNJ) to 7.48 percent
(benzaldehyde for GLKY). The pollutant-specific average CV ranged from 0.73 percent
(acetone) to 4.08 percent (tolualdehydes). The site-specific average CV ranged from 1.91 percent
for PXSS to 2.97 percent for INDEM.
Table 29-11. Carbonyl Compound Analytical Precision: Coefficient of Variation Based on
Replicate Analyses by Site
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
rolualdehydes
Valeraldehyde
Average by Site
AZFL
1.03
1.53
4.35
3.40
2.69
NA
1.61
4.08
NA
2.21
4.79
3.96
2.96
BTUT
0.44
0.38
3.77
1.53
2.11
NA
0.84
2.98
NA
1.39
4.17
2.83
2.04
CHNJ
0.25
0.35
2.72
1.95
1.97
NA
0.50
3.45
NA
2.33
4.55
3.39
2.15
DEMI
0.29
0.49
3.42
2.83
3.07
NA
1.30
4.21
NA
1.81
4.33
4.45
2.62
ELNJ
0.76
0.67
2.40
0.92
2.42
NA
1.22
3.98
NA
1.42
4.89
3.38
2.21
GLKY
0.93
0.60
7.48
2.69
2.87
NA
0.71
3.33
NA
1.90
3.60
4.92
2.90
GPCO
0.59
0.67
1.35
2.72
2.53
NA
0.92
3.36
NA
1.40
3.80
3.08
2.04
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29-37
-------
Table 29-11. Carbonyl Compound Analytical Precision: Coefficient of Variation Based on
Replicate Analyses by Site (Continued)
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes
Valeraldehyde
Average by Site
INDEM
1.47
0.69
4.60
2.46
3.05
NA
1.29
4.31
NA
2.59
4.73
4.52
2.97
MWOK
0.59
0.38
3.30
2.24
0.99
NA
0.49
3.22
NA
2.10
4.09
4.13
2.15
NBIL
0.95
1.19
3.82
2.59
4.86
NA
0.35
3.48
NA
2.60
2.94
4.34
2.71
NBNJ
0.84
0.42
3.62
2.55
2.61
NA
0.48
4.09
NA
1.99
2.91
1.60
2.11
OCOK
0.58
0.38
2.79
1.82
2.48
NA
0.61
3.04
NA
1.08
4.99
2.76
2.05
ORFL
0.52
1.02
3.62
3.11
1.56
NA
0.79
3.96
NA
2.23
5.06
4.51
2.64
PROK
0.41
0.55
3.44
1.76
1.74
NA
1.29
2.98
NA
2.08
3.25
2.72
2.02
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
Table 29-11. Carbonyl Compound Analytical Precision: Coefficient of Variation Based on
Replicate Analyses by Site (Continued)
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
rolualdehydes
Valeraldehyde
Average by Site
PXSS
1.23
0.89
1.82
1.22
1.93
NA
0.92
3.64
NA
1.64
3.81
2.03
1.91
S4MO
0.47
0.79
3.65
1.43
1.99
NA
0.43
3.87
NA
2.02
4.70
2.82
2.22
SEWA
1.26
1.59
3.86
1.90
3.83
NA
0.78
4.00
NA
2.69
2.42
3.01
2.53
SKFL
0.62
0.79
3.70
3.90
2.43
NA
0.64
3.85
NA
2.94
4.50
3.38
2.68
SPIL
0.27
0.56
3.13
1.90
2.90
NA
0.56
2.21
NA
1.82
4.20
3.17
2.07
SSSD
2.14
0.54
4.21
3.22
3.77
NA
0.81
3.49
NA
1.54
4.96
3.26
2.80
SYFL
0.56
0.56
3.32
2.91
3.51
NA
0.49
2.62
NA
2.02
4.53
4.28
2.48
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29-38
-------
Table 29-11. Carbonyl Compound Analytical Precision: Coefficient of Variation Based on
Replicate Analyses by Site (Continued)
Pollutant
Acetaldehyde
Acetone
Benzaldehyde
Butyraldehyde
Crotonaldehyde
2,5-Dimethylbenzaldehyde
Formaldehyde
Hexaldehyde
Isovaleraldehyde
Propionaldehyde
Tolualdehydes
Valeraldehyde
Average by Site
TMOK
0.47
0.55
2.89
2.73
1.79
NA
0.77
3.89
NA
2.30
3.25
2.60
2.12
TOOK
1.44
0.77
3.49
2.80
2.63
NA
1.25
4.71
NA
2.79
3.89
4.75
2.85
UCSD
0.59
1.01
4.34
2.91
4.25
NA
0.98
3.12
NA
3.12
3.11
4.69
2.81
WPIN
1.06
0.89
4.01
2.27
3.34
NA
1.10
3.49
NA
2.61
4.56
3.86
2.72
# of Pairs
326
326
324
324
316
0
326
324
0
326
269
317
~
Average
by
Pollutant
0.79
0.73
3.56
2.39
2.69
NA
0.84
3.57
NA
2.10
4.08
3.54
2.43
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designaled NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this
method is calculated from the site-specific averages and provided in the final column of the table.
29.3.4 PAH Analytical Precision
Table 29-12 presents analytical precision results from replicate analyses of all collocated
PAH samples as the CV per pollutant per site, the average CV per site, the average CV per
pollutant, and the overall average CV for NMP sites sampling PAHs. The analytical precision
results from replicate analysis of collocated samples show low- to mid-level variability among
sites, ranging from a CV of 0.82 percent (benzo(a)anthracene for SYFL) to 41.40 percent
(anthracene for DEMI). The pollutant-specific average CV ranged from 1.21 percent
(dibenz(a,h)anthracene) to 15.30 percent (anthracene). The site-specific average CV ranged from
3.15 percent for SEWA to 7.41 percent for DEMI. The overall average CV for all sites was
4.61 percent.
29-39
-------
Table 29-12. PAH Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site
Pollutant
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Coronene
Cyclopenta[cd]pyrene
Dibenz(a,h)anthracene
Fluoranthene
Fluorene
9-Fluorenone
Indeno( 1 ,2,3 -cd)pyrene
Naphthalene
Perylene
Phenanthrene
Pyrene
Retene
Average by Site
DEMI
8.73
3.26
41.40
36.75
4.41
2.75
2.51
2.79
2.61
1.71
3.96
NA
NA
3.43
3.38
3.34
4.55
2.85
NA
1.61
3.80
6.86
7.41
RUCA
2.73
2.09
4.19
2.43
NA
2.63
2.81
1.33
NA
3.65
NA
NA
NA
3.16
3.90
2.58
9.17
2.56
NA
1.11
3.79
3.50
3.23
SDGA
5.13
1.89
20.80
1.39
3.83
4.16
4.61
1.30
4.42
2.90
NA
2.21
NA
3.94
3.69
4.05
9.13
4.11
NA
1.74
4.06
4.46
4.62
SEWA
4.81
7.90
2.89
2.35
6.27
4.86
1.74
2.12
4.20
2.28
2.97
1.56
NA
2.61
3.38
2.96
0.91
2.51
NA
1.35
2.60
2.79
3.15
SYFL
2.57
13.34
7.21
0.82
7.42
3.68
5.91
3.35
7.24
3.24
10.94
NA
1.21
2.89
2.80
2.92
4.94
3.30
NA
2.22
2.78
4.31
4.66
# of Pairs
58
22
28
17
15
47
35
27
16
55
6
4
1
58
58
58
25
58
0
58
58
57
~
Average
by
Pollutant
4.80
5.70
15.30
8.75
5.48
3.62
3.52
2.18
4.62
2.76
5.96
1.89
1.21
3.21
3.43
3.17
5.74
3.06
NA
1.61
3.40
4.39
4.61
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29.3.5 Metals Analytical Precision
Table 29-13 presents analytical precision results from replicate analyses of all collocated
metals samples as the CV per pollutant per site, the average CV per site, the average CV per
pollutant, and the overall average CV for NMP sites sampling metals. The results from replicate
analyses of collocated samples show low- to mid-level variability among sites, ranging from a
CV of 0.30 percent (chromium for S4MO) to 34.02 percent (mercury for UNVT). The pollutant-
specific average CV ranged from 1.29 percent (lead) to 16.52 percent (mercury). The site-
29-40
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specific average CV ranged from 3.01 percent for TOOK to 12.56 percent for GLKY. The
overall average analytical precision was 7.91 percent.
Table 29-13. Metals Analytical Precision: Coefficient of Variation Based on Replicate
Analyses by Site
Pollutant
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Cobalt
Lead
Manganese
Mercury
Nickel
Selenium
Average by Site
BOMA
1.40
2.09
14.31
6.81
2.83
6.43
1.50
1.13
9.27
1.80
2.68
4.57
BTUT
1.17
11.01
24.85
7.53
NA
10.19
0.72
1.08
20.20
3.24
17.70
9.77
GLKY
2.85
11.23
17.82
4.95
NA
29.23
1.03
0.81
17.53
33.36
6.77
12.56
S4MO
0.96
7.21
13.30
2.79
0.30
19.55
0.61
1.15
11.51
9.58
8.85
6.89
TOOK
2.16
1.98
4.58
2.27
3.03
2.22
2.38
2.22
6.59
3.74
1.97
3.01
UNVT
2.24
16.36
NA
5.77
NA
15.71
1.52
3.44
34.02
2.86
13.83
10.64
# of Pairs
342
323
160
340
133
317
342
342
245
201
329
-
Average
by
Pollutant
1.80
8.32
14.97
5.02
2.05
13.89
1.29
1.64
16.52
9.10
8.63
7.91
NA = No pairs with concentrations greater than or equal to the MDL
BOLD ITALICS = EPA-designated NATTS Site
Gray shading indicates NATTS MQO Core Analyte
Orange shading indicates the site-specific average CV for this method; the overall average CV for this method is
calculated from the site-specific averages and provided in the final column of the table.
29.3.6 Hexavalent Chromium Analytical Precision
Table 29-14 presents analytical precision results from replicate analyses of all collocated
hexavalent chromium samples as the CV per site and the overall average CV for NMP sites
sampling hexavalent chromium. Hexavalent chromium is a NATTS MQO Core Analyte and the
sites shown are NATTS sites. The range of variability for hexavalent chromium was 3.56 percent
for HOWI to 13.83 percent for BTUT, with an overall average analytical precision of
6.69 percent.
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Table 29-14. Hexavalent Chromium Analytical Precision: Coefficient of Variation Based on
Replicate Analyses by Site
Site
BOMA
BTUT
CAMS 35
CHSC
DEMI
GLKY
GPCO
HOW
MONY
NBIL
PRRI
PXSS
RIVA
ROCH
S4MO
SDGA
SEWA
SKFL
SYFL
UNVT
WADC
# of Pairs
Average by Site
Average CV
8.29
13.83
5.22
7.32
4.56
5.30
8.03
3.56
5.54
6.44
7.19
4.92
6.26
9.40
6.57
5.44
5.64
5.71
5.27
7.74
8.34
223
6.69
BOLD ITALICS = EPA-designated
NATTS Site
Orange shading indicates the average CV
for this method
29.4 Accuracy
Laboratories typically evaluate their accuracy (or bias) by analyzing audit samples that
are prepared by an external source. The pollutants and the respective concentrations of the audit
samples are unknown to the laboratory. The laboratory analyzes the samples and the external
source compares the measured concentrations to the reference concentrations of those audit
samples and calculates a percent difference. Accuracy, or bias, indicates the extent to which
experimental measurements represent their corresponding "true" or "actual" values.
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Laboratories participating in the NATTS program are provided with proficiency test (PT)
audit samples for VOCs, carbonyl compounds, PAHs, metals, and hexavalent chromium, which
are used to quantitatively measure analytical accuracy. Tables 29-15 through 29-19 present
ERG's results from the 2011 NATTS PT audit samples for VOCs, carbonyl compounds, PAHs,
metals, hexavalent chromium, respectively. The program MQO for the percent difference from
the true value is ฑ 25 percent, and the values exceeding this criterion are bolded in the tables.
Shaded rows present results for NATTS MQO Core Analytes. The percent difference calculation
is:
Percent Difference =
:100
Where:
X\ is the analytical result from the laboratory;
Xi is the true concentration of the audit sample
Table 29-15. VOC NATTS PT Audit Samples-Percent Difference from True Value
Pollutant
Acrolein
Benzene
1,3 -Butadiene
Carbon Tetrachloride
Chloroform
1 ,2-Dibromoethane
1 ,2-Dichloroethane
Dichloromethane
1 ,2-Dichloropropane
cis- 1 ,3 -Dichloropropene
trans- 1 ,3 -Dichloropropene
1 , 1 ,2,2-Tetrachloroethane
retrachloroethylene
rrichloroethylene
Vinyl Chloride
November 2011
-20.3
10.2
10.9
25.4
-9.7
5.7
-11.8
6.4
2.8
21.5
41.3
1.1
0.8
-8.3
0.3
Gray shading indicates NATTS MQO Core Analyte
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Table 29-16. Carbonyl Compound NATTS PT Audit Samples-Percent Difference from
True Value
Pollutant
Acetaldehyde
Benzaldehyde
Formaldehyde
Propionaldehyde
November 2011
3.0
8.0
-3.4
-14.6
Gray shading indicates NATTS MQO Core
Analyte
Table 29-17. PAH NATTS PT Audit Samples-Percent Difference from True Value
Pollutant
Acenaphthene
Anthracene
Benzo(a)pyrene
Fluoranthene
Fluorene
Naphthalene
Phenanthrene
Pyrene
July 2011
-11.9
-13.6
-2.1
-9.4
-6.9
-13.9
-7.9
-6.9
Gray shading indicates NATTS MQO Core Analyte
Table 29-18. Metals NATTS PT Audit Samples-Percent Difference from True Value
Pollutant
Arsenic
Beryllium
Cadmium
Cobalt
Lead
Manganese
Nickel
Selenium
July 2011
1.1
-8.2
-6.0
-4.3
-6.3
-4.0
-6.8
-15.6
Gray shading indicates NATTS MQO Core
Analyte
Table 29-19. Hexavalent Chromium PT Audit Samples-Percent Difference from True
Value Across Multiple Samples
Pollutant
Hexavalent Chromium
July 2011
Concentration
#1
-2.6
Concentration
#2
-6.0
Concentration
#3
-1.7
Concentration
#4
-0.8
Gray shading indicates NATTS MQO Core Analyte
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The accuracy of the 2011 monitoring data can also be assessed qualitatively by reviewing
the accuracy of the monitoring methods and how they were implemented:
The sampling and analytical methods used in the 2011 monitoring effort have
been approved by EPA for accurately measuring ambient levels of various
pollutants - an approval that is based on many years of research into the
development of ambient air monitoring methodologies.
When collecting and analyzing ambient air samples, all field sampling staff and
laboratory analysts are required to strictly adhere to quality control and quality
assurance guidelines detailed in the respective monitoring methods. This strict
adherence to the well-documented sampling and analytical methods suggests that
the 2011 monitoring data accurately represent ambient air quality.
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30.0 Results, Conclusions, and Recommendations
The following discussion summarizes the results of the data analyses contained in this
report, renders conclusions based on those results, and presents recommendations applicable to
future air monitoring efforts. As demonstrated by the results of the data analyses discussed
throughout this report, NMP monitoring data offer a wealth of information for assessing air
quality by evaluating trends, patterns, correlations, and the potential for health risk and should
ultimately assist a wide range of audiences understand the complex nature of air pollution.
30.1 Summary of Results
Analyses of the 2011 monitoring data identified the following notable results,
observations, trends, and patterns in the program-level and state- and site-specific air monitoring
data.
30.1.1 National-level Results Summary
Number of participating NATTS sites. Twenty-five of the 51 sites are EPA-designated
NATTS sites (BOMA, BTUT, CAMS 35, CAMS 85, CELA, CHSC, DEMI, GLKY,
GPCO, HOWI, MONY, NBIL, PRRI, PXSS, RIVA, ROCH, RUCA, S4MO, SDGA,
SEW A, SJJCA, SKFL, SYFL, UNVT, and WADC).
Total number of samples collected and analyzed. Over 8,800 samples were collected
yielding over 218,900 valid measurements of air toxics.
Detects. The detection of a given pollutant is subject to the sensitivity limitation
associated with the analytical methods used and the limitations of the instruments.
Simply stated, a method detection limit is the lowest concentration of a target
pollutant that can be measured and reported with 99 percent confidence that the
pollutant concentration is greater than zero. Approximately 54 percent of the reported
measurements were above the associated MDLs. Of the 177 pollutants monitored,
only two pollutants were not detected over the course of the 2011 monitoring effort:
c/5-l,2-dichloroethylene and 2,5-dimethylbenzaldehyde.
Program-level Pollutants of Interest. The pollutants of interest at the program-level
are based on the number of exceedances, or "failures," of the risk screening values. In
addition, the 18 NATTS MQO Core Analytes (excluding acrolein) are inherently
classified as pollutants of interest. Only two NATTS MQO Core Analytes (beryllium
and vinyl chloride) did not fail any screens. Hexachloro-1,3-butadiene is new to the
program-level pollutants of interest for 2011.
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Noncancer Risk-Based Screening using A TSDR MRLs. Where an MRL was available,
all of the preprocessed daily measurements were less than the associated ATSDR
acute MRLs. Additionally, all of the quarterly or annual average concentrations of the
pollutants with MRLs were less than the associated ATSDR intermediate or chronic
MRLs.
Mobile Sources. Site-specific hydrocarbon concentrations had positive correlations
with county-level and 10-mile motor vehicle ownership data, traffic data, and VMT
data. While these correlations were not "strong", they do indicate that hydrocarbon
concentrations tend to increase with increasing motor vehicle activity data.
Carbon Tetrachloride. Although production of carbon tetrachloride has declined
sharply over the last 30 years due to its role as an ozone depleting substance, it has a
relatively long atmospheric lifetime and thus, is present in at similar levels at any
given location. NMP sites are located in a variety of locations across the county with
difference purposes behind the monitoring at each site. The relative uniformity in the
concentrations of carbon tetrachloride across the program confirms the ubiquitous
nature of this pollutant and is an indication of the representativeness of the data
generated under the program.
Seasonal Trends. Formaldehyde concentrations tended to be highest during the third
quarter of 2011, or during the period from July to September. Acenaphthene and
fluorene concentrations exhibit a similar pattern. Conversely, benzene concentrations
tended to be higher during the first or fourth quarters of the year, or between January
through March and October through December. Benzo(a)pyrene and 1,3-butadiene
concentrations exhibit a similar trend. Arsenic concentrations tended to be highest
between October and December.
30.1.2 State-level Results Summary
Arizona.
The Arizona monitoring sites are located in Phoenix. PXSS is a NATTS site; SPAZ is
a UATMP site.
PXSS sampled for VOCs, carbonyl compounds, PAHs, metals (PMio), and
hexavalent chromium. SPAZ sampled for VOCs only.
Twenty-three pollutants, of which 13 are NATTS MQO Core Analytes, failed screens
for PXSS. PXSS failed the second highest number of screens among all NMP sites.
Ten pollutants failed screens for SPAZ, of which four are NATTS MQO Core
Analytes.
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Of the pollutants of interest for PXSS, benzene had the highest annual average
concentration and was the only pollutant with an annual average concentration greater
than 1 |ig/m3 for this site.
Xylenes had the highest annual average concentration for SPAZ. Benzene and
ethylbenzene also had annual average concentrations greater than 1 |ig/m3.
PXSS had the highest annual average concentration of tetrachloroethylene,
hexavalent chromium, beryllium, and manganese among NMP sites sampling these
pollutants.
SPAZ had the highest annual average concentrations of 1,3-butadiene,
/>-dichlorobenzene, and ethylbenzene among NMP sites sampling these pollutants.
Annual average concentrations could not be calculated for the carbonyl compounds
for PXSS due to a sampler problem that led to the invalidation of carbonyl
compounds samples through the end of March 2011.
Sampling for metals (PMi0) and hexavalent chromium has occurred at PXSS for at
least 5 consecutive years; thus, a trends analysis was conducted for select pollutants.
The concentrations of arsenic, lead, and manganese increased for 2011 from 2010
levels.
Benzene and 1,3-butadiene had the highest cancer risk approximations for PXSS and
SPAZ. None of the pollutants of interest for either site had a noncancer hazard
approximation greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Maricopa
County, while toluene was the highest emitted pollutant with a noncancer toxicity
factor. Formaldehyde had the highest cancer toxicity-weighted emissions, while
acrolein had the highest noncancer toxicity-weighted emissions for Maricopa County.
California.
The three California monitoring sites are located in Los Angeles (CELA), Rubidoux
(RUCA), and San Jose (SJJCA). All three are NATTS sites.
CELA and RUCA sampled for PAHs only. SJJCA sampled for PAHs and metals
(PMio).
Three pollutants failed screens for CELA, of which one (naphthalene) is a NATTS
MQO Core Analyte. Naphthalene was the only pollutant to fail screens for RUCA.
Six pollutants failed screens for SJJCA, of which five are NATTS MQO Core
Analytes.
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Naphthalene had the highest annual average concentration for each site. The annual
average concentration of naphthalene for CELA was higher than the annual average
concentrations for RUCA and SJJCA, and fourth highest compared to all NMP sites
sampling naphthalene.
Of the pollutants of interest for each site, naphthalene exhibited the highest cancer
risk approximation for all three California sites. The noncancer hazard approximation
for each pollutant of interest was less than 1.0 for all three sites.
Formaldehyde was the highest emitted pollutant with a cancer toxicity factor in Los
Angeles, Riverside, and Santa Clara Counties; formaldehyde also had the highest
cancer toxicity-weighted emissions for Los Angeles and Santa Clara Counties while
hexavalent chromium had the highest cancer toxicity-weighted emissions for
Riverside County.
1,1,1 -Trichloroethane was the highest emitted pollutant with a noncancer toxicity
factor in Los Angeles County, while toluene was the highest emitted pollutant with a
noncancer toxicity factor in Riverside and Santa Clara Counties. Acrolein had the
highest noncancer toxicity-weighted emissions for all three counties.
Colorado.
The NATTS site in Colorado is located in Grand Junction (GPCO). There are also
four UATMP sites located northeast of Grand Junction in Garfield County. The sites
are located in the towns of Battlement Mesa (BMCO), Silt (BRCO), Parachute
(PACO), and Rifle (RICO).
GPCO sampled for VOCs, carbonyl compounds, PAHs, and hexavalent chromium.
The Garfield County sites sampled for SNMOCs and carbonyl compounds.
Twenty-three pollutants failed at least one screen for GPCO, of which eight are
NATTS MQO Core Analytes. The number of pollutants that failed screens for the
Garfield County sites ranged from four (BRCO) to five (BMCO, PACO, and RICO).
Of the pollutants of interest for GPCO, formaldehyde had the highest annual average
concentration, followed by acetaldehyde and benzene.
Annual average concentrations for the carbonyl compounds for the Garfield County
sites could not be calculated because these sites did not meet the necessary
completeness criteria. The same is true for SNMOCs for BMCO. Benzene had the
highest annual average concentration for the three remaining Garfield County sites;
PACO had the highest annual average benzene concentration of all three sites.
GPCO had the highest annual average concentrations of naphthalene and
benzo(a)pyrene among sites sampling PAHs. GPCO also had the fourth highest
annual average ethylbenzene concentration among all NMP sites sampling this
30-4
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pollutant. PACO, GPCO, and RICO are listed among the NMP sites with the highest
annual average concentrations for sites that sampled benzene.
VOC, carbonyl compound, and hexavalent chromium sampling has occurred at
GPCO for at least 5 consecutive years; thus, a trends analysis was conducted for
select pollutants. After several years without significant change, formaldehyde
concentrations decreased significantly from 2009 to 2010, then held steady in 2011.
Benzene concentrations exhibit an overall decreasing trend over recent years.
Concentrations of hexavalent chromium have increased at GPCO since 2009.
Formaldehyde had the highest cancer risk approximation for GPCO. Benzene had the
highest cancer risk approximation for each of the three Garfield County sites where
an annual average could be calculated (BRCO, PACO, and RICO). All noncancer
hazard approximations were less than 1.0 for all five Colorado sites.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Mesa
County, while formaldehyde was the highest emitted pollutant with a cancer toxicity
factor in Garfield County. Formaldehyde had the highest cancer toxicity-weighted
emissions for both counties.
While toluene was the highest emitted pollutant with a noncancer toxicity factor for
both Mesa and Garfield Counties, acrolein had the highest noncancer toxicity -
emissions.
District of Columbia
The Washington, D.C. monitoring site (WADC) is a NATTS site.
WADC sampled for hexavalent chromium and PAHs. The only pollutant to fail
screens for WADC was naphthalene.
The pollutant with the highest annual average concentration for WADC was
naphthalene, which was significantly higher than the annual average concentrations
for benzo(a)pyrene and hexavalent chromium.
Hexavalent chromium sampling has occurred at WADC for at least 5 consecutive
years; thus, a trends analysis was conducted. The average concentration of hexavalent
chromium increased significantly from 2009 to 2010 then held steady for 2011.
Naphthalene had the only cancer risk approximation for WADC greater than
1.0 in-a-million. None of the pollutants of interest had a noncancer hazard
approximation greater than 1.0.
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Benzene was the highest emitted pollutant with a cancer toxicity factor in the District
of Columbia, while toluene was the highest emitted pollutant with a noncancer
toxicity factor. Formaldehyde had the highest cancer toxicity-weighted emissions,
while acrolein had the highest noncancer toxicity-weighted emissions in the District.
Florida.
Three of the Florida monitoring sites are located in the Tampa-St. Petersburg-
Clearwater MSA (SYFL, AZFL, and SKFL) and two are located in the Orlando-
Kissimmee MSA (ORFL and PAFL). SKFL and SYFL are NATTS sites.
AZFL and ORFL sampled for carbonyl compounds only. SKFL and SYFL sampled
for hexavalent chromium and PAHs in addition to carbonyl compounds. PAFL
sampled only metals (PMio).
Acetaldehyde and formaldehyde were the only pollutants to fail screens for AZFL
and ORFL, where only carbonyl compounds were sampled. Five pollutants failed
screens for SKFL and four pollutants failed screens for SYFL. Arsenic was the only
pollutant to fail screens for PAFL, where only metals were sampled.
Acetaldehyde had the highest annual average concentration for AZFL, while
formaldehyde had the highest annual average concentration for SKFL, SYFL, and
ORFL. SYFL had the highest annual average concentration of formaldehyde among
the Florida sites. Manganese and lead had the highest annual average concentrations
for PAFL.
Carbonyl compound sampling has been conducted at AZFL, ORFL, SKFL, and
SYFL for at least 5 consecutive years; thus a trends analysis was conducted for
acetaldehyde and formaldehyde. Hexavalent chromium sampling has also been
conducted at SYFL for at least 5 consecutive years. From 2010 to 2011, acetaldehyde
concentrations have decreased at AZFL, SKFL, and SYFL while acetaldehyde
concentrations have increased at ORFL. Concentrations of formaldehyde increased
from 2010 to 2011 at SKFL, but have been steadily decreasing at ORFL since the
onset of sampling. Hexavalent chromium concentrations have been increasing since
2009 at SYFL.
For the Florida sites sampling carbonyl compounds, formaldehyde had the highest
cancer risk approximations. Arsenic had the highest cancer risk approximation for
PAFL. All noncancer hazard approximations for the pollutants of interest for the
Florida sites were less than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in all three
Florida counties. Benzene also had the highest cancer toxicity-weighted emissions for
Pinellas County, while formaldehyde had the highest cancer toxicity-weighted
emissions for Hillsborough and Orange Counties.
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Toluene was the highest emitted pollutant with a noncancer toxicity factor in all three
Florida counties. Acrolein had the highest noncancer toxicity-weighted emissions for
all three counties.
Georgia.
The SDGA monitoring site located in Decatur, south of Atlanta, is a NATTS site.
SDGA sampled for PAHs and hexavalent chromium. Naphthalene, acenaphthene, and
fluorene failed screens for SDGA, with naphthalene accounting for the majority of
the total failed screens.
Of the pollutants of interest for SDGA, naphthalene had the highest annual average
concentration, ranking tenth among NMP sites sampling PAHs.
Hexavalent chromium sampling has occurred at SDGA for at least 5 consecutive
years; thus, a trends analysis was conducted. The range of hexavalent chromium
measurements has decreased since the onset of sampling in 2006.
Naphthalene was the only pollutant of interest with a cancer risk approximation
greater than 1.0 in-a-million. None of the pollutants of interest for SDGA had a
noncancer hazard approximation greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in DeKalb
County, while toluene was the highest emitted pollutant with a noncancer toxicity
factor. Benzene also had the highest cancer toxicity-weighted emissions, while
acrolein had the highest noncancer toxicity-weighted emissions for DeKalb County.
Illinois.
The Illinois monitoring sites are located near Chicago. NBIL is a NATTS site located
in Northbrook and SPIL is a UATMP site located in Schiller Park.
Both Illinois sites sampled for VOCs and carbonyl compounds. NBIL also sampled
for SNMOCs, PAHs, hexavalent chromium, and metals (PMio).
Twenty-four pollutants failed screens for NBIL, of which 13 are NATTS MQO Core
Analytes. Sixteen pollutants failed screens for SPIL, of which six are NATTS MQO
Core Analytes.
Of the pollutants of interest for NBIL, chloroform had the highest annual average
concentration. This is also the highest annual average concentration of chloroform
among NMP sites sampling this pollutant. NBIL also had the highest annual average
concentration of fluorene among all NMP sites sampling PAHs.
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Formaldehyde had the highest annual average concentration for SPIL. SPIL had the
highest annual average concentrations of trichloroethylene and acrylonitrile among
NMP sites sampling these pollutants.
VOC and carbonyl compound sampling have been conducted at NBIL and SPIL for
at least 5 consecutive years. In addition, metals (PMio) and hexavalent chromium
sampling have been conducted at NBIL for at least 5 consecutive years. Thus, a
trends analysis was conducted for these methods for both sites. Concentrations of
acetaldehyde and 1,3-butadiene have an increasing trend at both sites in recent years.
The concentrations for several of the pollutants for which a trends analysis was
performed were at a minimum in 2009, particularly for SPIL.
Formaldehyde had the highest cancer risk approximation for NBIL, while
acrylonitrile had the highest cancer risk approximation for SPIL. All none
hazard approximations for the pollutants of interest for the Illinois sites w
acrylomtrile nad tne nignest cancer risk approximation tor brlL. All noncancer
hazard approximations for the pollutants of interest for the Illinois sites were less
than 1 0
Benzene was the highest emitted pollutant with a cancer toxicity factor in Cook
County, while formaldehyde had the highest cancer toxicity-weighted emissions.
Toluene was the highest emitted pollutant with a noncancer toxicity factor, while
acrolein had the highest noncancer toxicity-weighted emissions for Cook County.
Indiana.
There are two Indiana monitoring sites, one located in Indianapolis (WPIN), and a
second located in Gary, near Chicago (INDEM). Both are UATMP sites.
WPIN and INDEM sampled for carbonyl compounds only.
Formaldehyde and acetaldehyde failed screens for both INDEM and WPIN;
propionaldehyde also failed a single screen for INDEM.
Of the pollutants of interest, formaldehyde had the highest annual average
concentration for INDEM. Annual average concentrations for WPIN could not be
calculated due to intermittent sampler issues.
Carbonyl compound sampling has been conducted at INDEM for at least
5 consecutive years; thus, a trends analysis was conducted for acetaldehyde and
formaldehyde. The concentration of both acetaldehyde and formaldehyde decreased
dramatically at INDEM between 2008 and 2009, with little change since.
Formaldehyde had the highest cancer risk approximation for INDEM. Neither of the
pollutants of interest for INDEM had a noncancer hazard approximation greater than
1.0. Annual average concentrations could not be calculated for WPIN, therefore,
cancer risk and noncancer hazard approximations could not be calculated.
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Benzene was the highest emitted pollutant with a cancer toxicity factor in Marion and
Lake Counties. Coke oven emissions (PM) had the highest cancer toxicity-weighted
emissions for Lake County while formaldehyde had the highest cancer toxicity-
weighted emissions for Marion County.
Toluene was the highest emitted pollutant with a noncancer toxicity factor in both
Lake and Marion Counties. Acrolein had the highest noncancer toxicity-weighted
emissions for both counties.
Kentucky.
The Kentucky monitoring site is located near Grayson Lake, south of Grayson,
Kentucky (GLKY). GLKY is a NATTS site.
GLKY sampled for hexavalent chromium, metals (PMio), carbonyl compounds,
PAHs, and VOCs. Fifteen pollutants failed screens for GLKY, of which nine are
NATTS MQO Core Analytes.
Annual averages could not be calculated for metals (PMio) and carbonyl compounds
because sampling did not begin until May and August, respectively. Of the pollutants
of interest for which annual averages could be calculated, carbon tetrachloride and
benzene had the highest annual average concentrations for GLKY, though none of the
calculated annual average concentrations were greater than 1 |ig/m3.
Acrylonitrile had the highest cancer risk approximation for GLKY, followed by
benzene and carbon tetrachloride. None of the pollutants of interest for GLKY had
noncancer hazard approximations greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Carter
County and had the highest cancer toxicity-weighted emissions. Toluene was the
highest emitted pollutant with a noncancer toxicity factor, while acrolein had the
highest noncancer toxicity-weighted emissions in Carter County.
Massachusetts.
The Massachusetts monitoring site (BOMA) is a NATTS site located in Boston.
BOMA sampled for metals (PMio), PAHs, and hexavalent chromium.
Seven pollutants failed screens for BOMA, of which five are NATTS MQO Core
Analytes. Naphthalene accounted for nearly half of the site's failed screens.
Of the pollutants of interest, naphthalene had the highest annual average
concentration. The annual average beryllium concentration for BOMA ranked third
highest among sites sampling metals (PMio).
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Metals and hexavalent chromium sampling have been conducted at BOMA for at
least 5 consecutive years; thus, a trends analysis was conducted for arsenic,
hexavalent chromium, and manganese. The concentrations of these pollutants have
changed little in recent years.
The only pollutants of interest with cancer risk approximations greater than 1.0 in-a-
million were arsenic and naphthalene. None of the pollutants of interest for BOMA
had noncancer hazard approximations greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Suffolk
County, while formaldehyde had the highest cancer toxicity-weighted emissions.
Toluene was the highest emitted pollutant with a noncancer toxicity factor in Suffolk
County, while acrolein had the highest noncancer toxicity-weighted emissions.
Michigan.
The three Michigan monitoring sites are located in the Detroit area. DEMI is a
NATTS site located in Dearborn. RRMI and SWMI are UATMP sites located in
River Rouge and Detroit, respectively.
All three Michigan sites sampled carbonyl compounds; DEMI also sampled VOCs,
PAHs, and hexavalent chromium.
Nineteen pollutants failed screens for DEMI, of which eight are NATTS MQO Core
Analytes. Acetaldehyde and formaldehyde both failed screens for RRMI and SWMI;
propionaldehyde also failed one screen for SWMI.
Formaldehyde had the highest annual average concentration for all three Michigan
sites. Compared to other NMP sites, DEMI had the second highest annual average
concentration of chloroform among sites sampling VOCs. DEMI also had the highest
annual average concentration of acenaphthene and the second highest annual average
concentrations of fluorene and naphthalene among sites sampling PAHs. DEMI also
has the fourth highest annual average concentration of hexavalent chromium.
Hexavalent chromium, carbonyl compound, and VOC sampling has been conducted
at DEMI for at least 5 consecutive years; thus, a trends analysis was conducted for
select pollutants. The most notable trend is for benzene. Benzene concentrations
exhibit a steady decreasing trend although concentrations have leveled out in recent
years.
Formaldehyde had the highest cancer risk approximation for all three sites. None of
the pollutants of interest for the Michigan sites had a noncancer hazard approximation
greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Wayne
County, while coke oven emissions had the highest cancer toxicity-weighted
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emissions. Hydrochloric acid was the highest emitted pollutant with a noncancer
toxicity factor in Wayne County, while acrolein had the highest noncancer toxicity -
weighted emissions.
Missouri.
The NATTS site in Missouri (S4MO) is located in St. Louis.
S4MO sampled for VOCs, carbonyl compounds, PAHs, metals (PMio), and
hexavalent chromium.
Twenty-five pollutants failed at least one screen for S4MO, of which 13 are NATTS
MQO Core Analytes. S4MO failed the greatest number of screens among NMP sites.
Of the pollutants of interest, formaldehyde and acetaldehyde had the highest annual
average concentrations for S4MO. S4MO had the highest annual average
concentrations of hexachloro-1,3-butadiene, arsenic, cadmium, and lead among all
NMP sites sampling these pollutants.
Carbonyl compound, VOC, metals (PMio), and hexavalent chromium sampling have
been conducted at S4MO for at least 5 consecutive years; thus, a trends analysis was
conducted for select pollutants. Concentrations of acetaldehyde and benzene
decreased from 2010 to 2011. Concentrations of formaldehyde increased significantly
from 2010 to 2011.
Formaldehyde had the highest cancer risk approximation for S4MO. None of the
pollutants of interest for S4MO had a noncancer hazard approximation greater
than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in St. Louis
(city), while toluene was the highest emitted pollutant with a noncancer toxicity
factor. Hexavalent chromium had the highest cancer toxicity-weighted emissions,
while acrolein had the highest noncancer toxicity-weighted emissions in St. Louis
(city).
New Jersey.
The four UATMP sites in New Jersey are located in Chester (CHNJ), Elizabeth
(ELNJ), New Brunswick (NBNJ), and Paterson (PANJ).
CHNJ, ELNJ, and NBNJ sampled for VOCs and carbonyl compounds, while PANJ
sampled for VOCs only.
Seventeen pollutants failed at least one screen for CHNJ; 16 pollutants failed at least
one screen for ELNJ; 18 pollutants failed screens for NBNJ; and 10 failed screens for
PANJ.
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Of the pollutants of interest, formaldehyde had the highest annual average
concentration for CHNJ, ELNJ, and NBNJ. Annual average concentrations could not
be calculated for PANJ due to a combination of a shortened sampling duration
(sampling ended in the middle of May) and a l-in-12 day sampling schedule.
Compared to other NMP sites, CHNJ had the highest annual average concentration of
1,2-dichloroethane among sites sampling VOCs and ELNJ had the highest annual
average concentration of formaldehyde among sites sampling carbonyl compounds.
Carbonyl compound and VOC sampling has been conducted at CHNJ, ELNJ, and
NBNJ for at least 5 consecutive years; thus, a trends analysis was conducted for select
pollutants. Several of the pollutants for which a trends analysis was conducted exhibit
slight increasing trends from 2010 to 2011, most notably 1,3-butadiene concentrations
at CHNJ and acetaldehyde concentrations for ELNJ.
Formaldehyde had the highest cancer risk approximations for CHNJ, ELNJ, and
NBNJ. None of the pollutants of interest for any of the New Jersey sites had
noncancer hazard approximations greater than 1.0. Cancer risk and noncancer hazard
approximations were not available for PANJ because annual average concentrations
could not be calculated.
Benzene was the highest emitted pollutant with a cancer URE in Union, Middlesex,
Morris, and Passaic Counties. Benzene also had the highest toxicity-weighted
emissions for Morris and Passaic Counties, while formaldehyde had the highest
toxicity-weighted emissions for Union and Middlesex Counties.
Toluene was the highest emitted pollutant with a noncancer toxicity factor in all four
counties, while acrolein had the highest noncancer toxicity-weighted emissions for
each county.
New York.
The two New York monitoring sites are located in New York City (MONY) and
Rochester (ROCH). Both are NATTS monitoring sites.
Both New York sites sampled PAHs and hexavalent chromium.
Seven pollutants failed screens for MONY and four pollutants failed screens for
ROCH. Naphthalene failed the majority of screens for both sites.
Naphthalene had the highest annual average concentration for both MONY and
ROCH.
Naphthalene had the highest cancer risk approximation for both sites. None of the
pollutants of interest for either New York site had noncancer hazard approximations
greater than 1.0.
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Benzene was the highest emitted pollutant with a cancer toxicity factor for Bronx and
Monroe Counties and had the highest cancer toxicity-weighted emissions for both
counties.
Methanol was the highest emitted pollutant with a noncancer toxicity factor in Bronx
County, while toluene was the highest emitted pollutant with a noncancer toxicity
factor in Monroe County. Acrolein had the highest noncancer toxicity-weighted
emissions for both counties.
Oklahoma.
There are five UATMP sites in Oklahoma: two located in Tulsa (TOOK and TMOK),
one in Pryor Creek (PROK), one in Oklahoma City (OCOK), and one in the
Oklahoma City suburb of Midwest City (MWOK).
Each of the Oklahoma sites sampled for VOCs, carbonyls compounds, and metals
(TSP).
Twenty pollutants failed screens for TOOK; 19 failed screens for TMOK; 15 failed
screens for PROK; 17 failed screens for MWOK; and 16 failed screens for OCOK.
Of the pollutants of interest, formaldehyde had the highest annual average
concentration for each Oklahoma site.
TOOK had the highest annual average concentration of benzene among NMP sites
sampling this pollutant. The five Oklahoma sites account for the third through
seventh highest annual average concentrations of formaldehyde among NMP sites
sampling carbonyl compounds.
TOOK has sampled carbonyl compounds, VOCs, and TSP metals for at least
5 consecutive years, therefore a trends analysis was conducted for select pollutants.
Concentrations of acetaldehyde, benzene, 1,3-butadiene, and manganese (TSP)
exhibit an increasing trend since 2009.
Formaldehyde and benzene had the highest cancer risk approximations for all of the
Oklahoma monitoring sites. The benzene cancer risk approximation for TOOK is the
highest benzene cancer risk approximation program-wide. Arsenic had the highest
cancer risk approximations among the metals. None of the pollutants of interest for
the Oklahoma sites had a noncancer hazard approximation greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Mayes,
Oklahoma, and Tulsa Counties. Arsenic had the highest cancer toxicity-weighted
emissions for Mayes County while benzene had the highest cancer toxicity-weighted
emissions for Oklahoma and Tulsa Counties.
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Toluene was the highest emitted pollutant with a noncancer toxicity factor in Tulsa
and Oklahoma Counties, while hydrochloric acid was the highest emitted pollutant
with a noncancer toxicity factor in Mayes County. Acrolein had the highest
noncancer toxicity-weighted emissions for all three counties.
Rhode Island.
The Rhode Island monitoring site (PRRI) is located in Providence and is a NATTS
site.
PRRI sampled for PAHs and hexavalent chromium.
Five pollutants failed screens for PRRI; 86 percent of failed screens are attributable to
naphthalene.
The annual average concentration of naphthalene was significantly higher than the
annual averages for the other pollutants of interest.
Hexavalent chromium sampling has been conducted at PRRI for at least
5 consecutive years; thus, a trends analysis was conducted. Concentrations of
hexavalent chromium exhibit an increasing trend for the last 2 years of sampling.
Naphthalene had the highest cancer risk approximation for PRRI and is the only one
greater than 1.0 in-a-million; all noncancer hazard approximations for PRRI were less
than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Providence
County, while formaldehyde had the highest cancer toxicity-weighted emissions.
Toluene was the highest emitted pollutant with a noncancer toxicity factor, while
acrolein had the highest noncancer toxicity-weighted emissions for Providence
County.
South Carolina.
The South Carolina monitoring site (CHSC) is located near Chesterfield and is a
NATTS site.
CHSC sampled for hexavalent chromium and PAHs.
Naphthalene was the only pollutant to fail screens for CHSC. Naphthalene failed
three screens out of 60 measured detections.
The annual average concentration of naphthalene was significantly higher than the
annual average concentrations of the other two NATTS MQO Core Analytes.
Compared to other NMP sites sampling PAHs and hexavalent chromium, CHSC had
some of the lowest annual average concentrations.
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Hexavalent chromium sampling has been conducted at CHSC for at least
5 consecutive years; thus, a trends analysis was conducted. Hexavalent chromium
concentrations increased significantly from 2009 to 2010 then held steady for 2011.
The cancer risk approximations for the pollutants of interest for CHSC were less
than 1 in-a-million; all noncancer hazard approximations for CHSC were less than
1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in
Chesterfield County and had the highest cancer toxicity-weighted emissions. Toluene
was the highest emitted pollutant with a noncancer toxicity factor, while acrolein had
the highest noncancer toxicity-weighted emissions.
South Dakota.
The UATMP sites in South Dakota are located in Sioux Falls (SSSD) and Union
County (UCSD).
Both South Dakota sites sampled for VOCs, SNMOCs, and carbonyl compounds.
Fourteen pollutants failed screens for SSSD, of which five are NATTS MQO Core
Analytes. Thirteen pollutants failed screens for UCSD, of which six are NATTS
MQO Core Analytes.
Formaldehyde and acetaldehyde had the highest annual average concentrations for
both SSSD and UCSD and are the only two pollutants with annual averages greater
than 1.0 |ig/m3 for these sites. UCSD had the second highest concentration of
acrylonitrile among NMP sites sampling VOCs.
Formaldehyde had the highest cancer risk approximations for both sites. None of the
pollutants of interest for either South Dakota site had a noncancer hazard
approximation greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Minnehaha
and Union Counties, while formaldehyde had the highest toxicity-weighted emissions
for both counties.
Toluene was the highest emitted pollutant with a noncancer toxicity factor in
Minnehaha and Union Counties, while acrolein had the highest noncancer toxicity-
weighted emissions for both counties.
Texas.
There are two NATTS sites in Texas: one in Deer Park (CAMS 35) and one in
Karnack (CAMS 85).
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The CAMS 35 site sampled for PAHs and hexavalent chromium, while CAMS 85
sampled for hexavalent chromium only.
Five pollutants failed screens for CAMS 35, with naphthalene contributing to nearly
71 percent of the total failed screens. Hexavalent chromium did not fail any screens
for CAMS 85.
Of the pollutants of interest for CAMS 35, naphthalene had the highest annual
average concentration and is significantly higher than the annual averages for the
other pollutants of interest. The annual average concentration of hexavalent
chromium for CAMS 85 is less than half the annual average concentration for
CAMS 35. The annual average concentration of hexavalent chromium for CAMS 85
is an order of magnitude lower than its annual average for 2010. This may be
attributable to the use of stainless steel filter holders used in the sampler which may
have contaminated the samples. Changing to a Teflonฎ filter holder has resulted in a
decrease in hexavalent chromium concentrations at CAMS 85.
Naphthalene had the highest cancer risk approximation among the pollutants of
interest for CAMS 35 and was the only pollutant with a cancer risk approximation
greater than 1 in-a-million for both sites. None of the pollutants of interest for either
Texas site had a noncancer hazard approximation greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Harris
County, while formaldehyde had the highest cancer toxicity-weighted emissions.
Formaldehyde was the highest emitted pollutant with a cancer toxicity factor in
Harrison County, while hexavalent chromium had the highest cancer toxicity-
weighted emissions.
Toluene was the highest emitted pollutant with a noncancer toxicity factor in both
counties, while acrolein had the highest noncancer toxicity-weighted emissions.
Utah.
The NATTS site in Utah is located in Bountiful, north of Salt Lake City (BTUT).
BTUT sampled for VOCs, carbonyl compounds, SNMOCs, PAHs, metals (PMio),
and hexavalent chromium.
Twenty-one pollutants failed screens for BTUT, of which 12 are NATTS MQO Core
Analytes.
Of the pollutants of interest, dichloromethane had the highest annual average
concentration for BTUT, followed by formaldehyde, acetaldehyde, and benzene.
BTUT had the highest annual average concentration of formaldehyde among NMP
sites sampling carbonyl compounds.
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Sampling for carbonyl compounds, VOCs, SNMOCs, metals (PMio), and hexavalent
chromium have been conducted at BTUT for at least 5 consecutive years; thus, a
trends analysis was conducted for select pollutants. Concentrations of formaldehyde
have been increasing in recent years, while concentrations of benzene have decreased.
Concentrations of lead have an overall decreasing trend since the onset of sampling.
The pollutant with the highest cancer risk approximation for BTUT is formaldehyde.
None of the pollutants of interest had noncancer hazard approximations greater than
1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Davis
County and had the highest cancer toxicity-weighted emissions. Toluene was the
highest emitted pollutant with a noncancer toxicity factor, while acrolein had the
highest noncancer toxicity-weighted emissions for Davis County.
Vermont.
Two Vermont monitoring sites are located in or near Burlington (BURVT and
UNVT); a third monitoring site is located in Rutland (RUVT). UNVT is a NATTS
monitoring site.
UNVT sampled for VOCs, hexavalent chromium, PAHs, and metals (PMio). BURVT
and RUVT sampled for VOCs only.
Eleven pollutants failed screens for BURVT and seven failed screens for RUVT.
Thirteen pollutants failed screens for UNVT.
Benzene had the highest annual average concentration for BURVT and RUVT, while
carbon tetrachloride had the highest annual average concentration for UNVT. Annual
average concentrations of the pollutants of interest for UNVT were among the lowest
compared to NMP sites sampling the same pollutants.
UNVT has sampled hexavalent chromium for at least 5 consecutive years; thus, a
trends analysis was conducted. The number of non-detects has decreased in recent
years, resulting in an increase in the average concentration of hexavalent chromium
for UNVT.
Benzene and carbon tetrachloride have the highest cancer risk approximations for the
Vermont monitoring sites. None of the noncancer hazard approximations were greater
than an HQ of 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Chittenden
and Rutland Counties and also had the highest cancer toxicity-weighted emissions for
both counties. Toluene was the highest emitted pollutant with a noncancer toxicity
factor in both counties, while acrolein had the highest noncancer toxicity-weighted
emissions.
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Virginia.
The NATTS site in Virginia is located near Richmond (RIVA).
RIVA sampled for PAHs and hexavalent chromium.
Four PAHs failed screens for RIVA, although naphthalene contributed to nearly
95 percent of the total failed screens. Hexavalent chromium did not fail any screens.
Of the pollutants of interest, naphthalene had the highest annual average
concentration.
Naphthalene had the highest cancer risk approximation for RIVA and is the only one
with a cancer risk approximation greater than 1 in-a-million. None of the pollutants of
interest for RIVA had a noncancer hazard approximation greater than 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Henrico
County, while formaldehyde had the highest cancer toxicity-weighted emissions.
Toluene was the highest emitted pollutant with a noncancer toxicity factor in Henrico
County, while acrolein had the highest noncancer toxicity-weighted emissions.
Washington.
The NATTS site in Washington is located in Seattle (SEWA).
SEWA sampled for VOCs, carbonyl compounds, PAHs, metals (PMi0), and
hexavalent chromium.
Eighteen pollutants failed screens for SEWA, of which 12 are NATTS MQO Core
Analytes.
Of the pollutants of interest for SEWA, acetaldehyde and formaldehyde had the
highest annual average concentrations, although they are the lowest annual averages
among NMP sites sampling carbonyl compounds. SEWA had the highest annual
average concentration of nickel among NMP sites sampling metals (PMio).
Carbonyl compound, VOC, metals (PMio), and hexavalent chromium sampling has
been conducted at BTUT for at least 5 consecutive years; thus, a trends analysis was
conducted for select pollutants. Although most of the selected pollutants exhibit
increases from 2010 to 2011, the increase for formaldehyde is the only one that is
statistically significant.
Formaldehyde had the highest cancer risk approximation for SEWA. All of the
noncancer hazard approximations for the pollutants of interest for SEWA sites were
less than an HQ of 1.0.
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Benzene was the highest emitted pollutant with a cancer toxicity factor in King
County and had the highest cancer toxicity-weighted emissions. Toluene was the
highest emitted pollutant with a noncancer toxicity factor in King County, while
acrolein had the highest noncancer toxicity-weighted emissions.
Wisconsin.
The Wisconsin monitoring site is located in Horicon (HOWI) and is a NATTS site.
HOWI sampled for hexavalent chromium only.
Hexavalent chromium was detected in greater than 65 percent of samples collected
but did not fail any screens.
The annual average concentration of hexavalent chromium was on the low side
compared to other NMP sites sampling hexavalent chromium, ranking 15th of out
22 sites.
The cancer risk approximation for hexavalent chromium is less than 1 in-a-million
and the noncancer hazard approximation for hexavalent chromium is less than an HQ
of 1.0.
Benzene was the highest emitted pollutant with a cancer toxicity factor in Dodge
County and had the highest cancer toxicity-weighted emissions. Toluene was the
highest emitted pollutant with a noncancer toxicity factor in Dodge County, while
acrolein had the highest noncancer toxicity-weighted emissions.
30.1.3 Composite Site-level Results Summary
Twenty-eight pollutants were identified as site-specific pollutants of interest, based
on the risk-based screening process. Acetaldehyde and formaldehyde were the two
most common pollutants of interest among the monitoring sites. All 31 sites that
sampled carbonyl compounds had acetaldehyde and formaldehyde as pollutants of
interest. Benzene, 1,3-butadiene, and carbon tetrachloride were the most common
VOC pollutants of interest. Every site that sampled benzene (28) had it as a pollutant
of interest. All but one site that sampled PAHs (22) had naphthalene as a pollutant of
interest (based on the risk-based screening process).
Concentrations from two sites, CAMS 85 and HOWI, did not fail any screens.
However, only hexavalent chromium was sampled at these two sites. Hexavalent
chromium failed 65 percent of screens for CAMS 85 in 2010 but did not fail any for
2011. This difference is a result of replacing the stainless steel filter holder in the
sampler with a Teflonฎ filter holder. A similar exchange was made at the PXSS site,
where the number of failed screens was halved from 2010 to 2011.
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Formaldehyde frequently had the highest site-specific annual average concentration
among the site-specific pollutants of interest; formaldehyde had the highest annual
average concentration for 19 sites. Naphthalene had the next highest at 12.
The toxicity factor for formaldehyde used in the preliminary risk-based screening
process, the cancer risk approximation calculations, and the toxicity-weighting of
emissions decreased substantially since the 2007 report. This translated to a much
higher toxicity potential for formaldehyde, leading to more failed screens, higher
cancer risk approximations, and relatively higher toxicity-weighted emissions values
for the 2008-2009 through 2011 reports than in previous reports.
Formaldehyde, naphthalene, and benzene tended to have the highest cancer risk
approximations on a site-specific basis. The cancer risk approximation calculated for
BTUT from the annual average concentration of formaldehyde (58.42 in-a-million) is
the highest of all annual average-based cancer risk approximations. Four other sites
exhibited cancer risk approximations greater than 50 in-a-million for formaldehyde
(S4MO, OCOK, MWOK, and TMOK). One additional cancer risk approximation was
greater than 50 in-a-million, which was calculated from SPIL's annual average
concentration of acrylonitrile.
Carbon tetrachloride often had relatively high cancer risk approximations based on
annual average concentrations among the monitoring sites, ranging between 3 and 4
in-a-million across the sites sampling VOCs, but tended to have relatively low
emissions and toxicity-weighted emissions according to the NEI. This pollutant
appears only once in the emissions-based tables for counties with NMP sites
(CAMS 85).
None of the noncancer hazard approximations were greater than 1.0. The noncancer
hazard approximation calculated for TOOK's annual average concentration of
manganese (an HQ of 0.60) was the highest of all annual average-based noncancer
hazard approximations. Formaldehyde and naphthalene along with manganese tended
to have the highest noncancer hazard approximations on a site-specific basis.
Benzene, formaldehyde, and ethylbenzene often had the highest county-level
emissions for participating counties (of those with a cancer URE). Both benzene and
formaldehyde typically had the highest toxicity-weighted emissions, along with
1,3-butadiene (of those with a cancer URE).
Toluene, xylenes, and methanol were often the highest emitted pollutants (of those
with a noncancer RfC), although they rarely had top 10 toxicity-weighted emissions.
Acrolein tended to have the highest toxicity-weighted emissions of pollutants with
noncancer RfCs, although acrolein emissions were relatively low when compared to
other pollutants. However, due to the high toxicity of this pollutant, even low
emissions translated into high noncancer toxicity-weighted emissions; the toxicity-
weighted value was often several orders of magnitude higher than other pollutants.
Acrolein is a national noncancer risk driver according to NATA. Besides acrolein,
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formaldehyde and 1,3-butadiene tended to have the highest toxicity-weighted
emissions among the pollutants with noncancer RfCs.
30.1.4 Data Quality Results Summary
Completeness, precision, and accuracy were assessed for the 2011 monitoring effort. The
quality assessments presented in this report show that the 2011 monitoring data are of a known
and high quality, consistent with the intended data use.
To the largest extent, ambient air concentration data sets met MQO for completeness.
Only seven out of 123 site- and method-specific data sets failed to comply with the MQO of
85 percent completeness while 58 data sets achieved 100 percent completeness.
Method precision and analytical precision were determined for the 2011 NMP monitoring
efforts using CV calculations based on duplicate, collocated, and replicate samples. The
precision for each analytical method utilized during the 2011 NMP was within the MQO of
85 percent. The method precision presented in this report is based on analytical results greater
than or equal to the sample- and pollutant-specific MDL.
Analytical method accuracy is ensured by using proven methods, as demonstrated by
third-party analysis of proficiency test audit samples, and following strict quality control and
quality assurance guidelines.
30.2 Conclusions
Conclusions resulting from the data analyses of the data generated from the 2011 NMP
monitoring efforts are presented below.
There are a large number of concentrations that are greater than their respective risk
screening values, particularly for many of the NATTS MQO Core Analytes.
However, there were no instances where the preprocessed daily measurements or
time-period average concentrations were greater than the ATSDR MRL noncancer
health risk benchmarks.
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Where annual averages could be calculated and for those pollutants with available
cancer UREs, none of the cancer risk approximations were greater than 100 in-a-
million; 33 were greater than 10 in-a-million (24 for formaldehyde, six for benzene,
and three for acrylonitrile); and less than half were greater than 1.0 in-a-million.
Where annual averages could be calculated and for those pollutants with available
noncancer RfCs, none of the noncancer hazard approximations were greater than 1.0.
When comparing the highest emitted pollutants for a specific county to the pollutants
with the highest toxicity-weighted emissions, the listed pollutants were more similar
for the pollutants with cancer UREs than for pollutants with noncancer RfCs. This
indicates that pollutants with cancer UREs that are emitted in higher quantities are
often more toxic than pollutants emitted in lower quantities; conversely, the highest
emitted pollutants with noncancer RfCs are not necessarily the most toxic. For
example, toluene was the noncancer pollutant that was emitted in the
highest quantities for many NMP counties, but was not one of the pollutants
with highest toxicity-weighted emissions for any listed county. Conversely, while
acrolein had the highest noncancer toxicity-weighted emissions for every NMP
county, it was among the highest emitted pollutants for only one county.
The number of states and sites participating in the NMP changes from year to year.
Yet, many of the data analyses utilized in this report require data from year-round (or
nearly year-round) sampling. Of the 51 sites whose data are included in the 2011
report, only two sites sampled for an abbreviated duration (due to site initialization
and/or site closure/relocation). Of the 123 site-method combinations, only six site-
method combinations did not cover the entire year. As a result, the number of time-
period averages and subsequent risk-based analyses that could not be calculated
decreased significantly for 2011 compared to 2010 (and 2010 was improved from the
2008-2009 monitoring effort). Fewer data gaps allow for more complete results and
inter-site comparisons.
Of the 51 monitoring sites participating in the 2011 NMP, only two sampled for all
six available pollutant groups under the national program (BTUT and NBIL). Another
four sites sampled all five pollutant groups required for NATTS sites. The wide range
of pollutant groups sampled among the sites, which is often a result of different
purposes behind the monitoring at the sites, makes it difficult to draw definitive
conclusions regarding air toxics in ambient air in a global manner.
This report strives to represent the best laboratory practices and utilize the best data
analysis techniques available. Examples for 2011 include the improvement of MDLs
and the incorporation of updated values for various toxicity factors. This can lead to
adjusting the focus of the report to concentrate on the air quality issues of highest
concern. Thus, the NMP report is dynamic in nature and scope; yet this approach may
prevent the direct comparison of the current report to past reports. There are two
major differences between reports prior to 2010 and the 2011 report. First, all
statistical calculations include zero substitution for non-detect results (rather than just
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those calculations related to risk). Second, the detect criteria applied to quarterly
averages was removed and replaced with a completeness criteria, allowing for the
calculation of quarterly average concentrations for those pollutants detected less
frequently than others. The only significant differences between the 2010 and 2011
reports are in regards to the trend analysis. For the 2011 report, this analysis utilized
yearly average concentrations rather than 3-year rolling average concentrations. In
addition, the list of pollutants for which this analysis was performed was extended to
include lead.
30.3 Recommendations
Based on the conclusions from the 2011 NMP, a number of recommendations for future
ambient air monitoring efforts are presented below.
Continue participation in the National Monitoring Programs. Ongoing ambient air
monitoring at fixed locations can provide insight into long-term trends in air quality
and the potential for air pollution to cause adverse health effects among the general
population. Therefore, state and local agencies should be encouraged to either 1)
develop and implement their own ambient air monitoring programs based on proven,
consistent sampling and analysis methods and EPA technical and quality assurance
guidance, or 2) consider long-term participation in the NMP.
Participate in the National Monitoring Programs year-round. Many of the analyses
presented in the 2011 report require a full year of data to be most useful and
representative of conditions experienced at each specified location. Therefore, state
and local agencies should be encouraged to implement year-long ambient air
monitoring programs in addition to participating in future monitoring efforts. As
discussed above, there was marked improvement in this area for 2011.
Monitor for additional pollutant groups based on the results of data analyses in the
annual report. The risk-based analysis where county-level emissions are weighted
based on toxicity identifies those pollutants whose emissions may result in adverse
health effects in a specific area. If a site is not sampling for a pollutant or pollutant
group identified as particularly hazardous for a given area, the agency responsible for
that site should consider sampling for those compounds.
Strive to develop standard conventions for interpreting air monitoring data. The lack
of consistent approaches to present and summarize ambient air monitoring data
complicates direct comparisons between different studies. Thought should be given to
the feasibility of establishing standard approaches for analyzing and reporting air
monitoring data for programs with similar objectives.
Continue to identify and implement improvements to the sampling and analytical
methods. The improvements made to the analytical methods prior to the 1999-2000
UATMP allowed for the measurement of ambient air concentrations of 11 pollutants
that were not measured during previous programs. This improvement provides
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sponsoring agencies and a variety of interested parties with important information
about air quality within their area. Further research is encouraged to identify other
method improvements that would allow for the characterization of an even wider
range of components in air pollution and enhance the ability of the methods to
quantify all cancer and noncancer pollutants to at least their levels of concern (risk
screening concentrations).
Require consistency in sampling and analytical methods. The development of the
NATTS program has shown that there are inconsistencies in collection and analytical
methods that make data comparison difficult across agencies. Requiring agencies to
use specified and accepted measurement methods, consistent with the guidelines
presented in the most recent version of the NATTS TAD, is integral to the
identification of trends and measuring the effectiveness of regulation.
Perform case studies based on findings from the annual report. Often, the annual
report identifies an interesting tendency or trend, or highlights an event at a particular
site(s). For example, chloroform concentrations have been highest at NBIL for
multiple report years. Further examination of the data in conjunction with
meteorological phenomena and potential emissions events or incidents, or further site
characterization may help identify state and local agencies pinpoint issues affecting
air quality in their area.
Consider more rigorous study of the effect of automobile emissions on ambient air
quality using multiple years of data. Because many NMP sites have generated years
of continuous data, a real opportunity exists to evaluate the importance and impact of
automobile emissions on ambient air quality. Suggested areas of study include
additional signature compound assessments and parking lot characterizations.
Develop and/or verify HAP and VOC emissions inventories. State/local/tribal
agencies should use the data collected from NMP sites to develop and validate
emissions inventories, or at the very least, identify and/or verify emissions sources of
concern. Ideally, state/local/tribal agencies would compare the ambient monitoring
results with an emissions inventory for source category completeness. The emissions
inventory could then be used to develop modeled concentrations useful to compare
against ambient monitoring data.
Promulgate ambient air standards for HAPs. Concentrations of several pollutants
sampled during the 2011 program year were greater than risk screening values
developed by various government agencies. One way to reduce the risk to human
health would be to develop standards similar to the NAAQS for pollutants that
frequently exceed published risk screening levels.
Incorporate/Update Risk in State Implementation Plans (SIPs). Use risk calculations
to design State Implementation Plans to implement policies that reduce the potential
for human health risk. This would be easier to enforce if ambient standards for certain
HAPs were developed (refer to above recommendation).
30-24
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United States Office of Air Quality Planning and Standards Publication No. EPA-454/R-13-007a
Environmental Protection Air Quality Assessment Division August 2013
Agency Research Triangle Park, NC
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