&EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA 454/R-00-003
March 2000
Air
National Air Quality and
Emissions Trends Report, 1998
5.72
3.81
6.82,
BB Nitrate
BB Organic Carbon
BB Elemental Carbon
BB Crustal Material
C~i Sulfate
1998 Annual Average PM25 Concentrations (in ug/m3) in
Rural Areas of the United States
-------
-------
454/R-00-003
National Air Quality and
Emissions Trends Report,
1998
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emissions Monitoring and Analysis Division
Air Quality Trends Analysis Group
Research Triangle Park, North Carolina 27711
March 2000
> Printed on recycled paper.
-------
About the Cover
The map on the cover displays the 1998 annual average PM2.5 concentra-
tions at monitoring sites in the Interagency Monitoring of PROtected
Environments (IMPROVE) network. The IMPROVE network was estab-
lished in 1987 to track visibility impairment in the nation's most pristine
areas, like national parks and wilderness areas. (See Chapter 6 for more
information on the IMPROVE network.) The size of the pie charts is pro-
portional to the annual average concentration of measured PM2.5. The
slices of the pie charts show the percentages of the known chemical con-
stituents of PM2.5. The map reveals that rural PM2.5 concentrations vary
regionally, with sites in the East typically having higher annual average
concentrations. Levels at most sites in the West are roughly less than half
of those in the East.
Data Source: The IMPROVE network.
Disclaimer
This report has been reviewed and approved for publication by the U.S.
Environmental Protection Agency's Office of Air Quality Planning and
Standards. Mention of trade names or commercial products are not intended
to constitute endorsement or recommendation for use.
Acknowledgments
The Trends Team would like to acknowledge the members of EPA's Office of
Research and Development, Office of Atmospheric Programs, and Office
of Transportation and Air Quality for peer reviewing this report prior to
publication; Support for the statistical analyses of air toxics trends
provided under EPA contract 68D70066; Colorado State University for
providing summary data from the IMPROVE monitoring network;
Support for desktop publishing and Web site development provided
under EPA contract 68W99004; and the Trends Workgroup in EPA's Office
of Air Quality Planning and Standards for providing comments
throughout report development.
-------
Preface
This is the twenty-sixth annual report on air pollution trends in the
United States issued by the U.S. Environmental Protection Agency.
The report is prepared by the Air Quality Trends Analysis Group
(AQTAG) in Research Triangle Park, North Carolina and is directed
toward both the technical air pollution audience and other interest-
ed parties and individuals.
The report can be accessed via the Internet at http://www.epa.gov/
airtrends/. AQTAG solicits comments on this report and welcomes
suggestions regarding techniques, interpretations, conclusions, or
methods of presentation. Comments can be submitted via the web-
site or mailed to:
Attn: Trends Team
AQTAG (MD-14)
U.S. EPA
Research Triangle Park, NC 27711
Readers can access data from the Aerometric Information Retrieval
System (AIRS) at http://www.epa.gov/airsdata/ and real time air
pollution data at http://www.epa.gov/airnow/.
in
-------
IV
-------
Contents
Chapter 1
Executive Summary 1
Chapter 2 1
Chapters 2
Chapter 4 2
Chapters 3
Chapter 6 , 4
Chapter 7 5
References and Notes 6
Chapter 2
Criteria Pollutants — National Trends 9
Carbon Monoxide 11
Lead 17
Nitrogen Dioxide 22
Ozone 27
Air Quality Impact of Major Wildfires 38
Particulate Matter 40
Fine Particulate Matter (PM2.5) 45
Sulfur Dioxide 50
Chapter 3
Criteria Pollutants — Metropolitan Area Trends 59
Status: 1998 : 59
Trends Analysis 60
The Air Quality Index 61
Summary of AQI Analyses 62
References 63
Chapter 4
Criteria Pollutants — Nonattainment Areas 65
References 67
Chapter 5
Air Toxics 69
Background 69
National Air Toxics Assessment Activities 72
Atmospheric Deposition : 87
References 88
v
-------
Chapter 6
Visibility Trends .....91
Introduction 91
Nature and Sources of the Problem 91
Long-Term Trends (1970-1990) 94
Recent Trends (1989-1998) 94
Current Visibility Conditions 97
Programs to Improve Visibility 99
References 103
Chapter 7
Atmospheric Deposition of Sulfur and Nitrogen Compounds.... 105
Primary Atmospheric Deposition Monitoring Networks 105
National Atmospheric Deposition Network 106
Trends Analyses for Sulfate and Nitrate Concentrations in Wet Deposition 107
Clean Air Status and Trends Network 108
Dry Deposition 109
Concentration Trends Analysis at CASTNet Sites 109
References 114
Appendix A
Data Tables ..117
Appendix B
AIRS Methodology 189
AIRS Methodology 189
IMPROVE Methodology 193
Air Toxics Methodology 194
Emissions Estimates Methodology 195
References 196
VI
-------
Figures
Figure 2-1. Average daily maximum 1-hour CO concentrations by month, 1998 11
Figure 2-2. Trend in 2nd maximum non-overlapping 8-hour average CO concentrations, 1989-1998 12
Figure 2-3. Trend in 2nd maximum non-overlapping 8-hour average CO concentrations by type of location,
1989-1998 - 12
Figure 2-4. Trend in national total CO emissions, 1989-1998 '. , 13
Figure 2-5. CO emissions by source category, 1998 '. 13
Figure 2-6. Long-term, trend in 2nd maximum non-overlapping 8-hour average CO concentrations, 1979-1998 14
Figure 2-7. Trend in CO 2nd maximum non-overlapping 8-hour concentrations by EPA Region, 1989-1998 15
Figure 2-8. Highest 2nd maximum non-overlapping 8-hour average CO concentration county, 1998 16
Figure 2-9. Trend in maximum quarterly average Pb concentrations (excluding source-oriented sites), 1989-1998.. 18
Figure 2-10. Pb maximum quarterly mean concentration trends by location (excluding point-source-oriented sites),
1989-1998 : 18
Figure 2-11. National total Pb emissions trend, 1989-1998. 19
Figure 2-12. Pb emissions by source category, 1998 19
Figure 2-13. Long-term ambient Pb trend, 1979-1998 20
Figure 2-14. Trend in Pb maximum quarterly mean concentration by EPA Region, 1989-1998 20
Figure 2-15. Pb maximum quarterly concentration in the vicinity of Pb point sources, 1998 21
Figure 2-16. Highest Pb maximum quarterly mean by county, 1998 ". 21
Figure 2-17. Trend in annual NO2 mean concentrations, 1989-1998 23
Figure 2-18. Trend in annual mean NO2 concentrations by type of location, 1989-1998 23
Figure 2-19. Trend in national total NOX emissions, 1989-1998. , 24
Figure 2-20. NOX emissions by source category, 1998 24
Figure 2-21. Long-term trend in annual mean NO2 concentrations, 1979-1998.; , 25
Figure 2-22. Trend in NO2 maximum quarterly mean concentration by EPA Region, 1989-1998 26
Figure 2-23. Highest NO2 annual mean concentration by county, 1998 26
Figure 2-24. Trend in annual 2nd-highest daily maximum 1-hour, and 4th-highest daily 8-hour O3
concentrations, 1989-1998. ..:... - 28
Figure 2-25. Trend in O3 2nd maximum 1-hour concentration by EPA Region, 1989-1998. 29
Figure 2-26. Trend in O3 4th maximum 8-hour concentration by EPA Region, 1989-1998 29
Figure 2-27. Summer 1998 statewide ranks for temperature and precipitation 30
Figure 2-28. Trend in annual 2nd-highest daily maximum 1-hour O3 concentrations by location, 1989-1998 30
Figure 2-29. Trend in 4th-highest 8-hour O3 based on 34 CASTNet sites in the rural eastern United States,
1989-1998..., : 31
Figure 2-30. Trend in annual 4th-highest daily maximum 8-hour O3 concentrations in National Parks,
1989-1998 31
Figure 2-31. Trend in annual 2nd-highest daily maximum 1-hour O3 concentrations, 1979-1998 32
Figure 2-32. Comparison of actual and meteorologically adjusted 1-hr ozone trends, 1989-1998 33
Figure 2-33. Areas with PAMS networks , 33
Figure 2-34. The median changes in summer morning concentrations of the most abundant VOC species measured
at PAMS sites , : 34
Figure 2-35. Trend in national total anthropogenic VOC emissions, 1989-1998 •. 35
VII
-------
Figure 2-36. Anthropogenic VOC emissions by source category. 35
Figure 2-37. Highest second daily maximum 1-hour O3 concentration by county, 1998 36
Figure 2-38. Highest fourth daily maximum 8-hour O3 concentration by county, 1998 37
Figure 2-39. Smoke/dust over North America for May 15,1998 38
Figure 2-40. Smoke/dust over North America for May 16,1998 38
Figure 2-41. Smoke/dust over North America for May 28,1998 38
Figure 2-42. Smoke/dust over North America for June 22,1998 39
Figure 2-43. Smoke/dust over North American for June 26,1998. 39
Figure 2-44. Trend in annual mean PM,0 concentrations, 1989-1998 41
Figure 2-45. PM]0 annual mean concentration trends by location, 1989-1998 42
Figure 2-46. National PM10 emissions trend, 1989-1998 (traditionally inventoried sources only) 42
Figure 2-47. PMIO emissions from traditionally inventoried source categories, 1998 43
Figure 2-48. Total PM10 emissions by source category, 1998 43
Figure 2-49.' Trend in PM]0 annual mean concentration by EPA Region, 1989-1998 44
Figure 2-50. Highest 2nd maximum 24-hour PMIO concentration by county, 1998 44
Figure 2-51. Status of new PM^ Monitor Deployment, based on AIRS February, 2000 45
Figure 2-52. Class I Areas in the Improve Network meeting the data completeness criteria in Appendix B 46
Figure 2-53. Annual average 1998 PM^ concentrations (in ug/m3) at IMPROVE sites and contribution by
individual constituents. Pie chart sizes are scaled by annual average PM25 concentrations 46
Figure 2-54. PM2S Concentrations, 1989-1998 at eastern IMPROVE sites meeting trends criteria 47
Figure 2-55. PM^ Concentrations, 1989-1998 at western IMPROVE sites meeting trends criteria 47
Figure 2-56. PM^ Concentrations, 1989-1998, at the Washington, D.C. IMPROVE site 48
Figure 2-57. Seasonal patterns in rural PM25/1998 49
Figure 2-58. Trend in annual mean SO2 concentrations, 1989-1998 50
Figure 2-59. Annual mean SO2 concentration by trend location, 1989-1998 51
Figure 2-60. Trend in 2nd max 24-hour average SO2 concentrations, 1989-1998 51
Figure 2-61. National total SO2 emissions trend, 1989-1998 52
Figure 2-62. SO2 emissions by source category, 1998 52
Figure 2-63. Long-term ambient SO2 trend, 1979-1998 53
Figure 2-64. Trend in SO2 annual arithmetic mean concentration by EPA Region, 1989-1998. 53
Figure 2-65. Plants affected by Phase I of the Acid Rain Program 54
Figure 2-66. Highest 2nd maximum 24-hour SO2 concentration by county, 1998 55
Figure 3-1. Air Quality Index logo 62
Figure 3-2. Number of days with AQI values > 100, as a percentage of 1989 value 62
Figure 4-1. Location of nonattainment areas for criteria pollutants, September 1999 65
Figure 4-2. Classified ozone nonattainment areas where 1-hour standard still applies 66
Figure 5-la. Relative variability in VOC and aldehyde annual average concentrations among urban sites, based
on 1996 ambient measurements 74
Figure 5-lb. Relative variability in trace metal concentrations among urban sites, based on 1996 ambient
measurements 75
Figure 5-lc. Relative variability in trace metal concentrations among rural sites, based on 1996 ambient
measurements 75
Figure 5-2. Locations for urban and rural air toxics monitors with long-term data 76
Figure 5-3a. National trend in annual/average benzene concentrations in metropolitan areas, 1993-1998 78
Figure 5-3b. National trend in annual/average 1,3-butadiene concentrations in metropolitan areas, 1993-1998 79
Figure 5-3c. National trend in annual/average total suspended lead concentrations in metropolitan areas,
1993-1998 .' 79
Figure 5-3d. National trend in annual/average styrene concentrations in metropolitan areas, 1993-1998 80
Figure 5-3e. National trend in annual/average tetrachloroethylene concentrations in metropolitan areas,
1993-1998 80
VIII
-------
Figure 5-3f. National trend in annual/average toluene concentrations in metropolitan areas, 1993-1998 81
Figure 5-4a. Trend in annual average benzene concentrations for metropolitan sites in California, 1989-1998 82
Figure 5-4b. Trend in annual average 1,3-butadiene concentrations for metropolitan sites in California,
1989-1998 (.82
Figure 5-4c. Trend in annual average lead concentrations for metropolitan sites in California, 1989-1998 83
Figure 5-4d. Trend in annual average styrene concentrations for metropolitan sites in California, 1989-1998 83
Figure 5-4e. Trend in annual average tetrachloroethylene concentrations for metropolitan sites in California,
1989-1998 „. 84
Figure 5-4f. Trend in annual average toluene concentrations for metropolitan sites in California, 1989-1998 84
Figure 5-5. Trends in Annual Average Fine Particle Chromium Concentrations in Rural Areas, 1993-1998. 85
Figure 6-1. Images of Glacier National Park and Dolly Sods Wilderness Area 92
Figure 6-2. IMPROVE sites meeting data completeness requirements 93
Figure 6-3. Shenandoah National Park on clear and hazy days and the effect of adding 10 ug/m3 of fine particles
to each 94
Figure 6-4. Long-term trend for 75th percentile light coefficient from airport visual data (July-September) 95
Figure 6-5a. Total light extinction trends for eastern Class I areas for clearest, middle, and haziest 20 percent of
the days in the distribution, 1989-1998 96
Figure 6-5b. Total light extinction trends for western Class I areas for clearest, middle, and haziest 20 percent of
the days in the distribution, 1989-1998 96
Figure 6-6a. Aerosol light extinction in eastern Class I areas for the clearest 20 percent of the days in the
distribution, 1989-1998 97
Figure 6-6b. Aerosol light extinction in eastern Class I areas for the middle 20 percent of the days in the
distribution, 1989-1998 97
Figure 6-6c. Aerosol light extinction in eastern Class I areas for the haziest 20 percent of the days in the
distribution, 1989-1998 97
Figure 6-6d. Aerosol light extinction in western Class I areas for the clearest 20 percent of the days in the
distribution, 1989-1998 98
Figure 6-6e. Aerosol light extinction in western Class I areas for the middle 20 percent of the days in the
distribution, 1989-1998 98
Figure 6-6f. Aerosol light extinction in western Class I areas for the haziest 20 percent of the days in the
distribution, 1989-1998 ....". 98
Figure 6-7a. Aerosol light extinction (in Mm'1) for the clearest 20 percent days and contribution by individual
particulate matter constituents, based on 1995-1997 IMPROVE data 100
Figure 6-7b. Aerosol light extinction (in Mnr1) for the middle 20 percent days and contribution by individual
particulate matter constituents, based on 1995-1997 IMPROVE data 100
Figure 6-7c. Aerosol light extinction (in Mm'1) for the haziest 20 percent days and contribution by individual
particulate matter constituents, based on 1995-1997 IMPROVE data 101
Figure 6-8a. Current visibility impairment expressed in deciviews for the clearest 20 percent days based on
1995-1997 IMPROVE data 101
Figure 6-8b. Current visibility impairment expressed in deciviews for the middle 20 percent days based on
1995-1997 IMPROVE data 102
Figure 6-8c. Current visibility impairment expressed in deciviews for the haziest 20 percent days based on
1995-1997 IMPROVE data 102
Figure 7-1. The NADP/NTN Network 106
Figure 7-2. Percent differences in mean annual measured sulfate concentrations as compared to projected
concentrations for 1995-1996 for the eastern United States (from NADP/NTN) 107
Figure 7-3a. Trends in wet sulfate deposition (kg/ha); 1995-1997 108
Figure 7-3b. Trends in wet sulfate deposition (kg/ha); 1989-1991 108
Figure 7-4. CASTNet Network and subset of 34 sites used for 1989-1998 trends analysis 109
Figure 7-5a. Comparison of ambient sulfur dioxide concentrations in the rural eastern United States from
CASTNet monitoring data, 1990-1991 vs. 1997-1998 110
Figure 7-5b. Comparison of ambient sulfate concentrations in the rural eastern United States from
IX
-------
CASTNet monitoring data, 1990-1991 vs. 1997-1998 ............... . .............................................. . ........... : ........... HI
Figure 7-5c. Comparison of ambient total nitrate concentrations in the rural eastern United States from
CASTNet data, 1990-1991 vs. 1997-1998 [[[ HI
Figure 7-5d. Comparison of ambient ammonium concentrations in the rural eastern United States from
CASTNet data, 1990-1991 vs. 1997-1998 [[[ : ............................................. 112
Figure 7-6. Trend in ambient sulfates in the rural eastern United States, based on CASTNet monitoring data,
1989-1998 [[[ 112
Figure 7-7. Trend in ambient sulfur dioxide in the rural United States, based on CASTNet monitoring data,
1989-1998 [[[ • ................. • ....................... II3
Figure 7-8. Trend in annual average ambient sulfur dioxide and sulfate concentrations, based on CASTNet monitoring
data, and regional SO2 emissions from electric utilities in rural eastern United States, 1989-1998 ........... 113
Figure 7-9a. Trend in annual average ambient sulfur dioxide and sulfate concentrations, based on CASTNet
monitoring data, and regional'SO2 emissions from electric utilities in rural eastern United States by
calendar quarter, 1989-1998; quarter 1
Figure 7-9b. Trend in annual average ambient sulfur dioxide and sulfate concentrations, based on CASTNet
monitoring data, and regional SO2 emissions from electric utilities in rural eastern United States by
calendar quarter, 1989-1998; quarter 2 [[[ :
Figure 7-9c. Trend in annual average ambient sulfur dioxide and sulfate concentrations, based on CASTNet
monitoring data, and regional-SO2 emissions from electric utilities in rural eastern United States by
calendar quarter, 1989-1998; quarter 3
Figure 7-9d. Trend in annual average ambient sulfur dioxide and sulfate concentrations, based on CASTNet
monitoring data, and regional SO2 emissions from electric utilities in rural eastern United States by
calendar quarter, 1989-1998; quarter 4 [[[ 115
Figure A-l. (Multiple NA areas within a larger NA area) Two SO2 areas inside the Pittsburgh-Beaver Valley
ozone NA. Counted as one NA area .................................................. . [[[ 187
Figure A-2. (Overlapping NA areas) Searles Valley PM10 NA partially overlaps the San Joaquin Valley ozone NA.
-------
Tables
Table 2-1. NAAQS in effect as of December 1999 . 9
Table 2-2. Milestones in Auto Emissions Control 13
Table 2-3. Summary of 1997-1998 Changes in Summer 6-9 a.m. Mean Concentrations of NOx and TNMOC at
PAMS Sites 34
Table 2-4. Biogenic sources of VOC emissions by region 35
Table 2-5. Percent Contribution to PM25 by Component, 1998 47
Table 2-6. Total SO2 Emissions from Table I units and Non-Table I units, 1994-1998 (thousand short tons) 52
Table 3-1. Summary of MSA Trend Analyses, by Pollutant 60
Table 3-2. AQI Categories/Colors, and Ranges..-. , 61
Table 4-1. Areas Redesignated Between September 1998 and September 1999 67
Table 4-2. Revocations of Nonattainment Areas Only Between September 1998 and September 1999 67
Table 4-3. Nonattainment Status 67
Table 5-1. List of 33 Urban Air Toxics Strategy HAPs 71
Table 5-2. Comparison of Typical Urban and Rural Concentrations for VOCs and Aldehydes, Based on 1996
Ambient Measurements 73
Table 5-3. Comparison of Typical Urban and Rural Concentrations for Trace Metals, Based on 1996 Ambient
Measurements 73
Table 5-4. National Summary of Ambient HAP Concentration Trends in Metropolitan Areas, 1993-1998 77
Table 5-5. National Summary of Ambient HAP Concentration Trends in Rural Areas, 1993-1998 86
Table 7-1. Mean Annual Sulfate Wet Deposition, 1989-1998 in three sensitive regions in the eastern United States.. 107
Table A-l. National Air Quality Trends Statistics for Criteria Pollutants, 1989-1998 .'. 118
Table A-2. National Carbon Monoxide Emissions Estimates, 1989-1998 (thousand short tons) 120
Table A-3. National Lead Emissions Estimates, 1989-1998 (short tons) 121
Table A-4. National Nitrogen Oxides Emissions Estimates, 1989-1998 (thousand short tons) 122
Table A-5. National Volatile Organic Compounds Emissions"Estimates, 1989-1998 (thousand short tons) 123
Table A-6. National PM10 Emissions Estimates, 1989-1998 (thousand short tons) 124
Table A-7. Miscellaneous and Natural Particulate Matter Emissions Estimates, 1989-1998 (thousand short tons). 124
Table A-8. National Sulfur Dioxide Emissions Estimates, 1989-1998 (thousand short tons) 125
Table A-9. National Long-Term Air Quality Trends, 1979-1998 126
Table A-10. National Air Quality Trends by Monitoring Location, 1989-1998 127
Table A-ll. National Air Quality Trends Statistics by EPA Region, 1989-1998 128
Table A-12. Maximum Air Quality Concentrations by County, 1998 130
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1998 , 148
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 155
Table A-15. Number of Days with AQI Values Greater Than 100 at Trend Sites, 1989-1998,
and All Sites in 1998 180
Table A-16. (Ozone only) Number of Days with AQI Values Greater Than 100 at Trend Sites, 1989-1998,
and All Sites in 1998 ; 182
Table A-17. Condensed Nonattainment Areas List(a) ; 184
Table A-18. Trend in 8-hr ozone concentrations at National Park and National Monument sites, 1989-98 188
Table B-l. Number of Ambient Monitors Reporting Data to AIRS 189
XI
-------
Acronyms
AIRS Aerometric Information Retrieval
System
AQRV Air-Quality Related Values
AIRMoN Atmospheric Integrated Assessment
Monitoring Network
CAA Clean Air Act
CAAA Clean Air Act Amendments
CARB California Air Resources Board
CASAC Clean Air Scientific Advisory
Committee
CASTNet Clean Air Status and Trends Network
CEMs Continuous Emissions Monitors
CFR Code of Federal Regulations
CO Carbon Monoxide
CMSA Consolidated Metropolitan Statistical
Area
DST Daylight Savings Time
EPA Environmental Protection Agency
FRM Federal Reference Method
GDP Gross Domestic Product
GLM General Linear Model
HAPs Hazardous Air Pollutants
IADN Integrated Atmospheric Deposition
Network
I/M Inspection and Maintenance
Programs
IMPROVE Interagency Monitoring of PROtected
Environments
MACT Maximum Achievable Control
Technology
MARAMA Mid-Atlantic Regional Air
Management Association
MDN Mercury Deposition Network
MSA Metropolitan Statistical Area
MDL Minimum Detectable Level
NAAQS National Ambient Air Quality
Standards
NADP National Atmospheric Deposition
Program
NAMS National Air Monitoring Stations
NAPAP National Acid Precipitation
Assessment Program
NARSTO North American Research Strategy for
Tropospheric Ozone
NESCAUM Northeast States for Coordinated Air
Use Management
NMOC Non-Methane Organic Compound
NO2 Nitrogen Dioxide
NOX Nitrogen Oxides
NFS National Park Service
NTI National Toxics Inventory
O3 Ozone
OTAG The Ozone Transport Assessment
Group
PAHs Polyaromatic Hydrocarbons
PAMS Photochemical Assessment
Monitoring Stations
PAN Peroxyacetyl Nitrate
Pb Lead
PCBs Polychlorinated Biphenyls
PM10 Particulate Matter of 10 micrometers
in diameter or less
PM2 5 Particulate Matter of 2.5 micrometers
in diameter or less
POM Polycyclic Organic Matter
ppm Parts Per Million
PSI Pollutant Standards Index
RFC Reformulated Gasoline
RVP Reid Vapor Pressure
SLAMS State and Local Air Monitoring
Stations
SNMOC Speciated Non-Methane Organic
Compound
SO2 Sulfur Dioxide
SOX Sulfur Oxides
TNMOC Total Non-Methane Organic
Compound
TRI Toxic Release Inventory
TSP Total Suspended Particulate
UATMP Urban Air Toxics Monitoring Program
VMT Vehicle Miles Traveled
VOCs Volatile Organic Compounds
ug/m3 Micrograms Per Cubic Meter
XII
-------
XIII
-------
-------
CHAPTER
Executive Summary
http://wwwiepa.g6v/oar/aqtrnd98/chapter1.bdlf
Criteria pollutants are those pollutants
for which the United States
Environmental Protection Agency (EPA)
has established National Ambient Air
Quality Standards (NAAQS). They
include carbon monoxide (CO), lead
(Pb), nitrogen dioxide (N02), ozone (03),
paniculate matter (PM), and sulfur
dioxide (S02).
CHAPTER 2
This is the twenty-sixth annual report documenting air pollution trends in the
United States.1'25 This document highlights the Environmental Protection
Agency's most recent assessment of the nation's air quality, focusing on the
10-year period from 1989 to 1998. It features comprehensive information for
the criteria pollutants and hazardous air pollutants, as well as relevant ambient
air pollution information for visibility impairment and acid rain.
Discussions throughout this report are based on the principle that many of
the programs designed to reduce ambient concentrations of the criteria pollut-
ants also aid in reducing pollution that contributes to air toxics pollution, vis-
ibility impairment, and acid ram. Likewise, requirements under the various air
toxics, visibility, and acid rain programs can also help reduce emissions that
contribute to ambient concentrations of the criteria pollutants.
CRITERIA POLLUTANTS -
NATIONAL TRENDS
Percent Decrease in National
Air Quality Concentrations
1989-1998
Carbon Monoxide
Lead
Nitrogen Dioxide
Ozone*
Paniculate Matter (PM10)
Sulfur Dioxide
39
56
14
4
25
39
* based on 1-hour level.
Air quality concentrations are based
on actual measurements of pollutant
concentrations in the air at selected
monitoring sites across the country.
: Fine paniculate matter, or PM25, are
those particles whose aerodynamic size
is less than or equal to 2.5 micrometers.
EPA tracks trends associated with the criteria pollutant standards. The na-
tional and regional air quality trends, along with supporting emissions data,
are presented in this chapter. National average air quality has improved from
1989 to 1998 for all the criteria pollutants.
While the national trends have improved over this 10-year period, trends in
some areas, including rural locations, have worsened. Ozone concentrations,
for example, have increased at 17 of the 24 National Park Service sites with
trend data. Increases at nine of those sites are statistically significant. The
1998 levels were particularly high at two parks in the eastern United States,
•Shenandoah and the Great Smoky Mountains. Ozone levels at these sites were
the highest in a decade and 30^40 percent higher than the national ozone stan-
dard.26 Fine particle concentrations have also increased in some areas in the
rural East. PM2.s concentrations increased at 7 of the 10 rural eastern sites with
trend data from 1992 to 1998. During that same period, average PM2.s levels in
the western United States decreased 5 percent.
On July 18,1997, EPA revised the ozone and particulate matter standards
following a thorough scientific review process. In May 1999, however, the U.S.
Court of Appeals for the D.C. Circuit issued an opinion affecting these revised
standards. In particular, the court remanded the ozone standard back to EPA
for further consideration. The court also vacated the revised PMW standard
and remanded the PM2.s standards back to EPA for further consideration. Fol-
lowing the denial of a petition for a rehearing by the D.C. Circuit, the Justice
Department has filed a petition for review before the Supreme Court. See
CHAPTER 1
EXECUTIVE SUMMARY
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Spec/a/ Report Chapter 2 features a
special report on the impact of major
wildfires on U.S. air quality.
Chapter 2 for trends relating to the revised ozone and PM NAAQS and refer to
http://www.epa.gov/airlinks/ for up-to-date information concerning actions
surrounding the revised standards.
CHAPTER 3
CRITERIA POLLUTANTS-
METROPOLITAN AREA TRENDS
Summary of MSA Trend Analyses, by Pollutant
CO
Lead
NO2
Ozone
Ozone
PM10
PM,0
SO2
SO2
Trend Statistics
Second Max 8-hour
Max Quarterly Mean
Arithmetic Mean
Fourth Max 8-hour
Second Daily Max 1-hour
Weighted Annual Mean
90th Percentile
Arithmetic Mean
Second Max 24-hour
Total #
MSAs
139
90
97
198
198
211
211
148
148
#MSAs
Up
0
1
4
13
11
1
0
0
0
#MSAs
Down
Change
104
61
44
25
23
152
132
103
91
#MSAs
with No
Significant
35
28
' 49
160
164
58
79
45
57
Chapter 3 characterizes air quality on
a more local level, using three differ-
ent indicators. First, this chapter lists
the 1998 peak air quality concentra-
tions for metropolitan areas. Second,
ten-year trends are assessed for each
area using a statistical method to
measure whether the trend is up or
down. The results show that 21 areas
had a statistically significant upward
trend in ambient concentrations for at
least one criteria pollutant, while 221
areas had a statistically significant
downward trend for at least one
criteria pollutant. The third way in
which local air quality is evaluated is
by looking at the Air Quality Index
(AQI) in the nation's 94 largest met-
ropolitan areas. The AQI analysis
shows that between 1989 and 1998 the total number of "unhealthy" days de-
creased an average of 57 percent in southern California (which, for the pur-
poses of this analysis, includes the Los Angeles, Riverside, Bakersfield, and
San Diego), but actually rose 10 percent in the remaining major cities across
the United States.
CHAPTER 4
CRITERIA POLLUTANTS-
NONATTAINMENT AREAS
Nonattainment Status
Original 1999 1999 Pop.
# areas # areas (in 1000s)
CO
Pb
NO2
03
PMio
SO2
43
12
1
101
85
51
20
8
0
32
77
31
33,230
1,116
0
92,505
29,880
4,371
Chapter 4 summarizes the current status of nonattainment areas, which are
those areas not meeting the NAAQS for at least one of the six criteria pollut-
ants. Under the Clean Air Act Amendments (CAAA) of 1990, there were 274
areas designated nonattainment for at least one ambient air quality standard.
As of September 1999,121 areas are designated nonattainment. These areas
are displayed on a map in this chapter. A second map depicts the current
ozone nonattainment areas, color-coded to indicate the severity of the ozone
problem in each area. The condensed list of nonattainment areas as of Septem-
ber 1999 is presented in Table A-17. This table is also on the Internet at http://
www.epa.gov/airs/nonattn.html and is updated as areas are redesignated.
EXECUTIVE SUMMARY • CHAPTER 1
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
CHAPTER 5
AIR TOXICS
National Trend in Annual Average Benzene
Concentrations in Metropolitan Areas, 1993-1998
6.5-1
ST 6.0-
1> 5.5-
~a 5-°'
I 4'5'
g 4.0-
g 3.5-
f3.0-
2.5-
* 2.0-
1 "'
< 1.0-
0.5-
0.0-
Chapter 5 presents information on another
set of air pollutants regulated under the
CAA. Hazardous Air Pollutants (HAPs),
commonly called air toxics, are pollutants
known to cause or suspected of causing
cancer or other serious human health effects
or ecosystem damage. The CAA lists 188
such pollutants and targets the sources emit-
ting them for regulation. Examples of air
toxics include mercury, chromium, benzene,
and perchloroethylene ("perc"). Air toxics
are emitted from literally thousands of
sources, including familiar sources like elec-
tric utilities, automobiles, and dry cleaners.
In 1990, Congress amended Section 112 of
the CAA by adding a new approach to the
^ i regulation of HAPs. This new approach is
age 1997 1998 divided into two phases. The first requires
the development of technology-based emis-
sions standards for sources of the 188 HAPs. The second phase is to evaluate
remaining problems or risks and develop additional regulations to address
sources of those problems as needed.
The success of the Air Toxics Program depends on our ability to quantify
the impacts of air toxics emissions on public health and the environment. To
that end, EPA has initiated numerous National Air Toxics Assessment (NATA)
activities to help identify areas of concern, characterize risks, and track
progress. These activities include expanded air toxics monitoring, improving
and periodically updating emissions inventories, national- and local-scale air
quality and exposure modeling, and continued research on effects and assess-
ment tools.
Currently, there are approximately 300 monitoring sites producing ambient
data on HAPs. EPA is working together with state and local air monitoring
agencies to build upon these monitoring sites to develop a monitoring net-
work which is representative of air toxics problems on a national scale. EPA's
Photochemical Assessment Monitoring Stations (PAMS) also measure HAPs
among the many pollutants that are precursors of ozone. Although these
existing data sources are limited in their geographic scope, they still provide
useful information on the trends in ambient air toxics. The results generally
reveal downward trends for most of the monitored HAPs. The most consistent
improvement is apparent for benzene, which is predominantly emitted by mobile
sources. Benzene decreased 37 percent from 1993 to 1998, with much of the re-
duction occurring between 1994 and 1996. This reduction is due, in large part,
to the use of reformulated gasoline.
CHAPTER 1
EXECUTIVE SUMMARY
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
CHAPTER 6
VISIBILITY TRENDS
i
The CAA authorizes EPA to protect visibility, or visual air quality, through a
number of programs. In 1987, the Interagency Monitoring of PROtected Vi-
sual Environments (IMPROVE) visibility monitoring network was established
as a cooperative effort between EPA, National Park Service, U.S. Forest Ser-
vice, Bureau of Land Management, U.S. Fish & Wildlife Service, and state
governments. The objectives of the network are to establish current condi-
tions, to track progress toward the national visibility goal by documenting
long-term trends, and to provide information for determining the types of
pollutants and sources primarily responsible for visibility impairment.
The trends analyses presented in this chapter are based on data from the
IMPROVE network. There were 34 sites having data adequate for assessing
trends between 1989 and 1998. Because of the significant regional variations
in visibility conditions, the trends are grouped into eastern and western re-
gions, rather than a national aggregate. The trends are presented in terms of
the annual average values for the "clearest," "typi-
cal," and "haziest" days monitored each year.
The results show that, in general, visibility is
worse in the east than in the west. In fact, the worst
visibility days in the west are only slightly more im-
paired than the best days in the east. The 10-year
trends show that visibility in the west has improved
slightly for all three ranges (clearest, typical, and
haziest days), while visibility in the east does not
seem to be improving for any of the ranges. In fact,
eastern visibility impairment on the haziest days has
worsened from 1997 to 1998, and the Great Smoky
Mountains National Park experienced its worst vis-
ibility in more than a decade.
In April of 1999, EPA issued the final regional haze regulation. This regula-
tion addresses visibility impairment in national parks and wilderness areas
that is caused by numerous sources located over broad regions. The program
lays out a framework within which states can work together to develop imple-
mentation plans that are designed to achieve "reasonable progress" toward
the national visibility goal of no human-caused impairment in the 156 manda-
tory Class I federal areas across the country. Implementation of the PM and
Ozone NAAQS in conjunction with a future regional haze program is ex-
pected to improve visibility in urban as well as rural areas across the country.
EXECUTIVE SUMMARY • CHAPTER 1
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
CHAPTER 7
ATMOSPHERIC DEPOSITION OF
SULFUR AND NITROGEN COMPOUNDS
Comparison of ambient sulfate concentrations in the rural eastern United States
from CASTNet monitoring data, 1990-1991 vs. 1997-1998.
1990-1991
1997-1998
Decrease in ambient sulfate
concentrations in the rural
eastern United States,
1990-1991 vs. 1997-1998.
Acidic deposition or "acid rain" oc-
curs when emissions of sulfur diox-
ide (802) and oxides of nitrogen
(NOx) in the atmosphere react with
water, oxygen, and oxidants to form
acidic compounds. These com-
pounds fall to the Earth in either dry
form (gas and particles) or wet form
(rain, snow, and fog). Some are car-
ried by the wind, sometimes hun-
dreds of miles, across state and
national borders. In the United
States, about 64 percent of annual
SC>2 emissions and 26 percent of NOX
emissions are produced by electric
utility plants that burn fossil fuels.
The National Atmospheric Deposi-
tion Program/National Trends Net-
work (NADP/NTN) and the Clean Air Status and Trends Network
(CASTNet), two monitoring networks described in detail in the chapter, moni-
tor wet and dry acid deposition, respectively. NADP/NTN consists of nearly
200 sites nationwide, while CASTNet contains 79 sites. These sites monitor a -
number of compounds, including sulfates and nitrates, which are formed from
SC>2 and NOX reacting in the atmosphere.
Wet deposition data from the NADP/NTN show that sulfate concentra-
tions in precipitation have decreased over the past two decades. In 1995 and
1996, concentrations of sulfates in precipitation over a large area of the eastern
United States exhibited a dramatic and unprecedented reduction. Sulfates
have been estimated to be 10-25 percent lower than levels expected with at
contm.uation of the 1983-1994 trend. This important reduction in acid precipi-
tation is directly related to the large regional decreases in SC>2 emissions result-
ing from phase I of the Acid Rain program (see the SO2 section in Chapter 2 for
more details). Nitrate concentrations in recent years at the NADP/NTN sites
are not appreciably different from historical levels.
Dry deposition data from the CASTNet sites in the eastern rural United
States show that average sulfate concentrations decreased 22 percent between
1989 and 1998. However, a 10-percent increase in average sulfate concentra-
tions occurred between 1997 and 1998. Most of the increase occurred during
the second and third calendar quarters. Between these warmer months of
1997 and 1998, regional sulfur dioxide emissions increased 12 percent and
average sulfate concentrations increased 21 percent. The higher summertime
emissions in 1998 are attributed, in part, to the extra demand on electric utili-
ties due to extremely warm temperatures throughout the Southeast.
The trend in nitrate concentrations is essentially flat, corresponding to the small
change in NOX emissions during this period. The highest nitrate concentrations
are found in Ohio, Indiana, and Illinois, while the highest sulfate concentra-
tions are adjacent to the Ohio Valley and in northern Alabama, which correspond
to the locations of large electric utilities.
CHAPTER 1
EXECUTIVE SUMMARY
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
REFERENCES AND NOTES
1. The National Air Monitoring Program: Air Quality and Emissions
Trends-Annual Report, EPA-450/l-73-001a and b, U.S. Environmental Pro-
tection Agency, Office of Air Quality Planning and Standards, Research
Triangle Park, NC 27711, July 1973.
2. Monitoring and Air Quality Trends Report, 1972, EPA-450/1-73-004, U.S.
Environmental Protection Agency, Office of Air Quality Planning and Stan-
dards, Research Triangle Park, NC 27711, December 1973.
3. Monitoring and Air Quality Trends Report, 1973, EPA-450/1-74-007, U.S.
Environmental Protection Agency, Office of Air Quality Planning and Stan-
dards, Research Triangle Park, NC 27711, October 1974.
4. Monitoring and Air Quality Trends Report, 1974, EPA-450/1-76-001, U.S.
Environmental Protection Agency, Office of Air Quality Planning and Stan-
dards, Research Triangle Park, NC 27711, February 1976.
5. National Air Quality and Emissions Trends Report, 1975, EPA-450/1-76-002,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, November 1976.
6. National Air Quality and Emissions Trends Report, 1976, EPA-450/1-77-002,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, December 1977.
7. National Air Quality and Emissions Trends Report, 1977, EPA-450/2-78-052,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, December 1978.
8. 1980 Ambient Assessment-Air Portion, EPA-450/4-81-014, U.S. Environmen-
tal Protection Agency, Office of Air Quality Planning and Standards, Re-
search Triangle Park, NC 27711, February 1981.
9. National Air Quality and Emissions Trends Report, 1981, EPA-450/4-83-011,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, April 1983.
10. National Air Quality and Emissions Trends Report, 1982, EPA-450/4-84-002,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, March 1984.
11. National Air Quality and Emissions Trends Report, 1983, EPA-450/4-84-029,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, April 1985.
12. National Air Quality and Emissions Trends Report, 1984, EPA-450/4-86-001,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, April 1986.
13. National Air Quality and Emissions Trends Report, 1985, EPA-450/4-87-001,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, February 1987.
14. National Air Quality and Emissions Trends Report, 1986, EPA-450/4-88-001,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, February 1988.
15. National Air Quality and Emissions Trends Report, 1987, EPA-450/4-89-001,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, March 1989.
16. National Air Quality and Emissions Trends Report, 1988, EPA-450/4-90-002,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, March 1990.
6 EXECUTIVE SUMMARY • CHAPTER 1
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
17. National Air Quality and Emissions Trends Report, 1989, EPA-450/4-91-003,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, February 1991.
18. National Air Quality and Emissions Trends Report, 1990, EPA-450/4-91-023,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, November 1991.
19. National Air Quality and Emissions Trends Report, 1991, EPA-450/R-92-001,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, October 1992.
20. National Air Quality and Emissions Trends Report, 1992, EPA-454/R-93-031,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, October 1993.
21. National Air Quality and Emissions Trends Report, 1993, EPA-454/R-94-026,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, October 1994.
22. National Air Quality and Emissions Trends Report, 1994, EPA-454/R-95-014,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, October 1995.
23. National Air Quality and Emissions Trends Report, 1995, EPA-454/R-96-005,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, October 1996.
24. National Air Quality and Emissions Trends Report, 1996, EPA-454/R-97-013,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, January 1998.
25. National Air Quality and Emissions Trends Report, 1996, EPA-454/R-97-013,
U.S. Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, January 1998.
26. Based on the level of the 8-hour ozone standard (0.08 ppm).
CHAPTER 1
EXECUTIVE SUMMARY
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
8 EXECUTIVE SUMMARY • CHAPTER 1
-------
CHAPTER
Criteria Pollutants
National Trends
•http://www.epa.gov/oar/aqtrnd98/chapter2.pdf
This chapter presents national and
regional trends for each of the pollut-
ants for which the United states Envi-
ronmental Protection Agency (EPA)
has established National Ambient Air
Quality Standards (NAAQS). NAAQS
are in place for the following six crite-
ria pollutants: carbon monoxide
(CO), lead (Pb), nitrogen dioxide
(NO2), ozone (O3), particulate matter
(PM), and sulfur dioxide (SO2). Table
2-1 lists the NAAQS for each pollut-
ant in terms of the level and averag-
ing time of the standard used to
evaluate compliance.
There are two types of standards:
primary and secondary. Primary
standards protect against adverse
human health effects, whereas sec-
ondary standards protect against
welfare effects such as damage to
crops, ecosystems, vegetation, build-
ings, and decreased visibility. There
are primary standards for all of the
criteria pollutants, and some pollut-
ants (PM and 802) have primary
standards for both long-term (annual
average) and short-term (24 hours or
less) averaging times. Short-term
standards most directly protect
people from adverse health effects
associated with peak short-term ex-
posures to air pollution, while
long-term standards can protect
people from adverse health effects
associated with short- and long-term
exposures to air pollution. Second-
Table 2-1. NAAQS in effect as of December 1999.
IT— . -
| Pollutant
r
£-
o
O i •
: H -liti* ™ U. ' IB . i •!,.:
t"Pb
t '
t NOZ
i"
|-03
r.
t-:, . ,-
fer
l-PMio
»--•
t
^
|PM2.5
t. .' '
|so2 ;
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
ary standards have been established
for each criteria pollutant except CO.
Secondary standards are identical to
the primary standards, with the ex-
ception of SO2. Approximately 134
million people in the United states
reside in counties that did not meet
the primary standard for at least one
of the criteria pollutants for the single
year 1998.
CO
Pb
PM
PM..
SO,
Any NAAQS
«•! ^S-bour)| 131.4
Date nol yet available.
{8-hour) J 133.9
20
40 60 80 100 120 140
Millions of Persons
Number of people living in counties with
air quality concentrations above the level
of NAAQS in 1998.
On July 18, 1997, EPA revised the
ozone and PM NAAQS. The averag-
ing time of the ozone standard
changed from a 1-hour average to an
8-hour average to protect against
longer exposure periods that are of
concern for both human health and
welfare. The primary PM standards
were revised to change the form of
the PMjo standards and to add two
new PM^s standards to protect
against fine particles.
In May 1999, however, the U.S.
Court of Appeals for the D.C. Circuit
issued an opinion affecting these
revised standards. In particular, the
court remanded the ozone standard
back to EPA for further consideration.
The court also vacated the revised
PMio standard and remanded the
PM^s standards back to EPA for fur-
ther consideration. Following the
denial of a petition for a rehearing by
the D.C. Circuit, the Justice Depart-
ment has filed a petition for review
before the Supreme Court. Refer to
http://www.epa.gov/aklinks for up-
to-date information concerning ac-
tions surrounding the revised
standards.
The trends information presented
in this chapter is based on two types
of data: ambient concentrations and
emissions estimates. Ambient con-
centrations are measurements of
pollutant concentrations in the ambi-
ent air from monitoring sites across
the country. This year's report con-
tains trends data accumulated from
1989 to 1998 on the criteria pollutants
at thousands of monitoring stations
located throughout the United states.
The trends presented here are de-
rived from the composite average of
these direct measurements. The
averaging times and air quality sta-
tistics used in the trends calculations
relate directly to the NAAQS.
The second type of data presented
in this chapter are national emissions
estimates. These are based largely on
engineering calculations of the
amounts and kinds of pollutants
emitted by automobiles, factories,
and other sources over a given pe-
riod. In addition, some emissions
estimates are based on measurements
from continuous emissions monitors
(CEMs) that have recently been in-
stalled at major electric utilities to
measure actual emissions. This re-
port incorporates data from CEMs
collected between 1994 and 1998 for
NOX and SO2 emissions at major
electric utilities. The emissions data
summarized in this chapter and in
Appendix A were obtained from the
National Air Pollutant Emission Trends
Report, 1900-1998, which can be
found at http://www.epa.gov/ttn/
chief/trends98/emtrnd.html.
Changes in ambient concentra-
tions do not always track changes in
emissions estimates. There are four
known reasons for this. First, be-
cause most monitors are positioned
in urban, population-oriented locales,
air quality trends are more likely to
track changes in urban emissions
rather than changes in total national
emissions. Urban emissions are gen-
erally dominated by mobile sources,
while total emissions in rural areas
may be dominated by large station-
ary sources such as power plants and
smelters.
Second, emissions for some pollut-
ants are calculated or measured in a
different form than the primary air
pollutant. For example, concentra-
tions of ozone are caused by VOC
emissions as well as NOX emissions.
Third, the amount of some pollut-
ants measured at monitoring loca-
tions depends on what chemical
reactions, if any, occur in the atmo-
sphere during the time it takes the
pollutant to travel from its source to
the monitoring station.
Finally, meteorological conditions
often control the formation and
buildup of pollutants in the ambient
air. For example, peak ozone concen-
trations typically occur during hot,
dry, stagnant summertime conditions;
CO is predominately a cold weather
problem; also, the amount of rainfall
can affect particulate matter levels
and the frequency of forest fires.
For a more detailed discussion of
the methodology used to compute
the trend statistics in this chapter,
please refer to Appendix B.
10 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, \
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Emissions Trends
Figure 2-4 shows that national total
CO emissions have decreased 16
percent since 1989. Emissions from
all transportation sources have de-
creased 16 percent during the past 10
years. Despite a 23-percent increase
in vehicle miles traveled (VMT),
emissions from on-road vehicles
decreased 24 percent during the past
10 years as a result of automotive
emissions control programs. Total
CO emissions decreased 5 percent
since 1997, while CO emissions from
on-road vehicles recorded a 2-percent
decline. Figure 2-5 shows that the
transportation category, composed of
on-road and off-road sources, ac-
counts for 79 percent of the nation's
total CO emissions in 1998.
Table 2-2 lists some of the major
milestones in the control of emissions
from automobiles starting with the
Clean Air Act (CAA) of 1970. At the
national level, these measures, which
have led to reductions in emissions of
CO as well as other pollutants, in-
clude establishing national standards
for tailpipe emissions, new vehicle
technologies, and clean fuels pro-
grams. State and local emissions
reduction measures include inspec-
tion and maintenance (I/M) pro-
grams and transportation
management programs.
Figure 2-2. Trend in 2nd maximum non-overlapping 8-hour average CO
concentrations, 1989-1998.
15
Concentration, ppm
10
0
nj-90th Percentile
-Mean
-Median
J_10th Percentile
363 Sites
NAAQS
89 90 91 92 93 94 95 96 97 98
Figure 2-3. Trend in 2nd maximum non-overlapping 8-hour average CO
concentrations by type of location, 1989-1998.
Concentration, ppm
7
Rural (12 sites) Suburban (148 sites) Urban (200 sites)
89 90 91 92 93 94 95 96 97 98
12 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1938
Figure 2-4. Trend in national total CO emissions, 1989-1998.
Thousand Short Tons Per Year
120,000
100,000
80,000
60,000
40,000
20,000
fj Fuel Combustidn
n Transportation
Industrial Processing
Miscellaneous
Figure 2-5. CO emissions by source category, 1998.
Transportation 78.6%
Industrial Processes 5.4%
Fuel Combustion 6.0%
Miscellaneous 10.0%
Table 2-2. Milestones in Motor Vehicle
Emissions Control
1970 New Clean Air Act sets auto
emissions standards.
1971 Charcoal canisters appear to
meet evaporative standards.
1972 EG R valves appear to meet NOX
standards.
1974 Fuel economy standards are set.
1975 The first catalytic converters
appear for hydrocarbon, CO.
Unleaded gas appears for use in
catalyst equipped cars.
1981 3-way catalysts with on-board
computers and O2 sensors ap-
pear.
1983 I/M programs are established in
64 cities.
1989 Fuel volatility limits are set for
RVP.
1990 CAAA set new tailpipe standards.
1992 Oxy-fuel introduced in cities with
high CO levels.
1993 Limits set on sulfur content of
diesel fuel.
1994 Phase-in begins of new vehicle
standards and technologies.
1995 On-board diagnostic systems in
1996 model year cars.
1998 Sales of 1999 model year Califor-
nia emissions equipped vehicles
begin in the Northeast.
In the area of clean fuels, the 1990
Clean Air Act Amendments (CAAA)
require oxygenated gasoline pro-
grams in several regions of the coun-
try during the winter months. Under
the program regulations, a minimum
oxygen content (2.7 percent by
weight) is required in gasoline to
ensure more complete fuel combus-
tion.U Of the 36 CO nonattainment
areas that initially implemented the
program in 1992,25 areas partici-
pated in the program during January
and February 1998, while 17 areas
continued to use oxygenated fuels
during November and December
1998. An analysis of the oxygenated
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 13
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
fuels program in several cities with
winter oxygenated gasoline pro-
grams showed reductions in ambient
CO concentrations of about 10 per-
cent.3 Other studies estimated that
the oxy-fuel effect was an average
total reduction in ambient CO con-
centrations of 7 to 14 percent overall
for the eight winter seasons from
1986 through 1994/M-
Blue Ribbon Panel on
Oxygenates in Gasoline
In November 1998, in response to the
public concern regarding the detec-
tion of MTBE (methyl tertiary butyl
ether—one of two fuel oxygenates
used in reformulated gasoline to help
improve air quality) hi water, EPA
Administrator Carol M. Browner
announced the creation of a blue
ribbon panel of leading experts from
the public health and scientific com-
munities, automotive fuels industry,
water utilities, and local and state
governments to review the important
issues posed by the use of MTBE and
other oxygenates in gasoline. The
Panel's final report stated that "the
Wintertime Oxyfuel Program contin-
ues to provide a means for some
areas of the country to come into, or
maintain, compliance with the carbon
monoxide standard. Only a few met-
ropolitan areas continue to use MTBE
in this program. In most areas today,
ethanol can, and is, meeting these
wintertime needs for oxygen without
raising fuel volatility concerns given
the season of the year. The Panel
recommends that the Wintertime
Oxyfuel program be continued (a) for
as long as it provides a useful com-
pliance and/or maintenance tool for
the affected states and metropolitan
areas, and (b) assuming that the clari-
fication of state and federal authority
described above is enacted to enable
Figure 2-6. Long-term trend in 2nd maximum non-overlapping 8-hour average CO
concentrations, 1979-1998.
Concentration, ppm
14
12
10
8
6
1979-88
(251 sites)
1989-98
(363 sites)
79 81 83 85 87 89 91 93 95 97 98
states, where necessary, to regulate
and/or eliminate the use of gasoline
additives that threaten drinking wa-
ter supplies."6 The Panel's Executive
Summary and final report entitled
Achieving Clean Air and Clean Water.
The Report of the Blue Ribbon Panel on
Oxygenates in Gasoline can be found
on the Panel's homepage at: http://
www.epa.gov/oms/consumer/fu-
els/oxypanel/blueribb.htm.
National 20-Year Trends
Because of the annual loss and re-
placement of ambient monitoring
sites (e.g., redevelopment, new leases,
etc.), too few sites are able to meet a
20-year trends data completeness
criteria. Thus, long-term trends are
assessed by piecing together two
separate 10-year trends databases.
Although there are differences in the
mix of trend sites for the two periods
(251 vs. 363 sites), Figure 2-6 shows a
consistent decline in CO concentra-
tions during the past 20 years. Na-
tionally, the 1998 composite average
ambient concentration is 58 percent
lower than 1979, and is the lowest
level recorded during the past 20
years of monitoring.
Regional Trends
The map in Figure 2-7 shows the
regional trends in ambient CO con-
centrations during the past 10 years,
1989-1998. All 10 EPA Regions re-
corded 10-year declines in CO levels
as measured by the regional compos-
ite mean concentrations. The largest
10-year concentration reductions are
in the Northcentral, Rocky Mountain
and Northwest states. Smaller re-
ductions can be seen in the New
England, West, South and Midwest
regions. Two regions (Region 5 and
Region 7) saw increases in the com-
posite mean CO concentration be-
14 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-7. Trend in CO 2nd maximum non-overlapping 8-hour concentrations by EPA Region, 1989-1998.
f 42%
5.8
47%
f 44%
f 48%
f 39%
f 21%
f 35%
f 38%
The National Trend
6.2
3.8
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2.
Concentrations are ppm.
Note: These trends are
influenced by the
distribution of monitoring
locations in a given region
and, therefore, can be
driven largely by urban
concentrations. For this
reason, they are not
indicative of background
regional concentrations.
tween 1997 and 1998 (increases of 3
percent and 14 percent, respectively).
1998 Air Quality Status
The map in Figure 2-8 shows the
variations in CO concentrations
across the country in 1998. The air
quality indicator is the largest annual
second maximum 8-hour CO concen-
tration measured at any site in each
county. The bar chart to the left of the
map displays the number of people
living in counties within each concen-
tration range. The colors on the map
and bar chart correspond to the col-
ors of the concentration ranges dis-
played in the map legend. Only
seven of the 526 monitoring sites
reporting ambient CO data to the
Aerometric Information Retrieval
System (AIRS) failed to meet the CO
NAAQS in 1998. These seven sites
were located in six counties—Los
Angeles County, CA; Fairbanks Bur-
ough, AK; Clarke County, NV (Las
Vegas, NV); Polk County, IA (Des
Moines, IA); Hancock County, WV
(Weirton, WV); and Imperial County,
CA (Calexico, CA). The two sites in
this latter area are located just north
of the border crossing with Mexicali,
Mexico. There are 10 million people
living in these six counties, compared
to the 1997 count of three counties
with a total population of 9 million
people.
Data Sources
The CO ambient trends plotting
points and emissions totals, by
source category, are listed in Tables
A-l and A-2. The plotting points for
the 20-year trend charts are listed in
Table A-9. The 1998 county maxi-
mum second-highest non-overlap-
ping 8-hour CO concentrations are
listed in Table A-ll.
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 15
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-8. Highest 2nd maximum non-overlapping 8-hour average CO concentration by county, 1998.
Concentration (ppm)
<4.5
4.5-9.4
9.5-12.4
12.5-15.4
16 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS W3PORT,
Lead
I Air Quality Concentrations
1 1989-98 56% decrease
1997-98
no change
Emissions
1989-98
1997-98
27% decrease
1 % increase
Nature and Sources
Twenty years ago, automotive
sources were the major contributor of
lead emissions to the atmosphere. As
a result of EPA's regulatory efforts to
reduce the content of lead in gasoline,
the contribution from the transporta-
tion sector has declined. Today,
metals processing is the major source
of lead emissions to the atmosphere.
The highest ambient air concentra-
tions of lead are found in the vicinity
of ferrous and nonferrous smelters,
battery manufacturers, and other
stationary sources of lead emissions.
Health and Environmental
Effects
Exposure to lead occurs mainly
through inhalation and through in-
gestion of lead in food, water, soil, or
dust. It accumulates in the blood,
bones, and soft tissues. Lead can also
adversely affect the kidneys, liver,
nervous system, and other organs.
Excessive exposure to lead may cause
neurological impairments such as
seizures, mental retardation, and/or
behavioral disorders. Even at low
doses, lead exposure is associated
with changes in fundamental enzy-
matic, energy transfer, and homeo-
static mechanisms in the body. At
low doses, fetuses and children may
suffer from central nervous system
damage. Recent studies show that
lead may be a factor in high blood
pressure and subsequent heart dis-
ease. Recent studies also indicate
that neurobehavioral changes may
result from lead exposure during the
child's first years of life.
Airborne lead can also have ad-
verse impacts on the environment.
Wild and domestic grazing animals
may ingest lead that has deposited
on plant or soil surfaces or that has
been absorbed by plants through
leaves or roots. Animals, however,
do not appear to be more susceptible
or more sensitive to adverse effects
from lead than humans. For this rea-
son, the secondary standard for lead
is identical to the primary standard.
At relatively low concentrations
(2-10 ug/m3), lead can inhibit plant
growth and result in a shift to more
tolerant plant species growing near
roadsides and stationary source
emissions. In spite of the fact that the
majority of soil lead becomes bound
so that it is insoluble, immobile, and
biologically unavailable, elevated soil
lead concentrations have been ob-
served to cause shifts in the microbial
community (fungi and bacteria),
reduced numbers of invertebrates,
reduced decomposition and nitrifica-
tion rates, and altered other soil pa-
rameters. Because lead remains in
the soil, soil concentrations continue
to build over time, even when depo-
sition rates are low. Thus, another
concern is that acid precipitation may
be increasing the mobility and
bioavailability of soil lead in some
places.
Lead enters water systems mainly
through urban runoff and sewage
and industrial effluents. Most of this
lead is readily complexed and bound
in the sediment. However, water
lead concentrations can reach levels
that are associated with increased
mortality and impaired reproduction
in aquatic invertebrates and blood
and neurological changes in fish.
Given the above effects, there con-
tinue to be implications for the long-
term impact of lead on ecosystem
function and stability. (See also the
Toxics chapter and the December 1990
OAQPS Staff Paper (EPA-450/
2-89-022)).
Primary and Secondary
Standards
The primary and secondary NAAQS
for lead is a quarterly average con-
centration not to exceed 1.5 ug/m3.
National 10-Year Trends
The statistic used to track ambient
lead air quality is the maximum
quarterly mean concentration of each
year. A total of 189 ambient lead
monitors met the trends data com-
pleteness criteria for the 10-year peri-
od 1989-1998. Point-source oriented
monitoring data were excluded from
all ambient trends analyses presented
in this section to avoid masking the
underlying urban trends. Figure 2-9
indicates that between 1989 and 1998,
maximum quarterly average lead
concentrations decreased 56 percent at
population-oriented monitors. Be-
tween 1997 and 1998, national aver-
age lead concentrations (approaching
the minimum detectable level) re-
mained unchanged. Figure 2-10 looks
at urban, rural, and suburban 10-year
trends separately. The figure shows
that background levels of lead are
similar in the three demographic
regions.
Emissions Trends
Figure 2-11 shows that total lead
emissions decreased 27 percent be-
tween 1989 and 1998. The large am-
bient and emissions reductions are a
waning result of the phase-out of
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS
17
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
leaded gasoline. Table A-3, which
lists lead emissions by major source
category, shows that on-road vehicles
accounted for 64 percent of the
10-year emissions decline. Between
1997 and 1998, lead emissions esti-
mates did not change substantially.
Figure 2-12 shows that industrial
processes were the major source of
lead emissions in 1998, accounting
for 74 percent of the total. The trans-
portation sector (on-road and
non-road sources) now accounts for
only 13 percent of total 1998 lead
emissions, with most of that coming
from aircraft.
National 20-Year Trends
The effect of the conversion to un-
leaded gasoline usage on ambient
lead concentrations is most impres-
sive when viewed over a longer peri-
od, such as illustrated in Figure 2-13.
Between 1979 and 1998, ambient
concentrations of lead declined 96
percent. This large decline tracks
well with overall lead emissions,
which declined 98 percent between
1979 and 1998.
Regional Trends
Figure 2-14 segregates the ambient
trend analysis by EPA Region. Al-
though most regions showed large
concentration reductions between
1989 and 1998, there were some inter-
mittent upturns. Many of the
"bumps" in the graphs can be attrib-
uted to the inherent variability asso-
ciated with data reported near the
minimum detectable level.
1998 Air Quality Status
The large reductions in long-term
lead emissions from transportation
sources have changed the nature of
the ambient lead problem in the Unit-
ed States. Because industrial pro-
Figure 2-9. Trend in maximum quarterly average Pb concentrations (excluding
source-oriented sites), 1989-1998.
2.0I
Concentration, ug/m3
1.5
1.0
0.5
0.0
r-,-9tith Percentile"
-Mean
^-Median
-10th Percentile
189 Sites
NAAQS
89 90 91 92 93 94 95 96 97 98
Figure 2-10. Pb maximum quarterly mean concentration trends by location (excluding
point-source-oriented sites), 1989-1998.
Concentration, ug/m3
0.12
0.1
0.08
0.06
0.04
0.02
Rujjal (5 sites) Suburban (98 sites) Urban (82 sites)
/\ —
89 90 91 92 93 94 95 96 97 98
18 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-11. National total Pb emissions trend, 1989-1998.
Short Tons Per Year
6,0001
Fuel. Combustion | Industrial Processing Q Transportation
5,000
89 90 91 92 93 94 95 96 97 98
Figure 2-12. Pb emissions by source category, 1998.
Fuel Combustion 12.7%
Transportation 13.1%
Including on-road
and off-road sources.
Industrial Processes 74.2%
cesses are now responsible for all
violations of the lead standard, the
lead monitoring strategy now focuses
on emissions from these point sourc-
es. The map in Figure 2-15 shows the
lead monitors located in the vicinity
of major sources of lead emissions.
In 1998, five lead point sources had
one or more source-oriented monitors
that violated the NAAQS. These five
sources are ranked in Figure 2-15
according to the site with the greatest
maximum quarterly mean. Various
enforcement and regulatory actions -
are being actively pursued by EPA
and the states for these sources.
The map in Figure 2-16 shows the
highest quarterly mean lead concen-
tration by county in 1998. Five coun-
ties, with a total population of 4.3
million and containing the point
sources identified in Figure 2-15, did
not meet the lead NAAQS in 1998.
Monitoring Status
Because of the shift in ambient air
monitoring focus from mobile-source
emissions to stationary point sources
of lead air pollution, EPA revised the
lead air monitoring regulations by
publishing a new rule on January 20,
1999. This action was taken at the
direct request of numerous state and
local agencies whose on-road mobile-
source oriented lead monitors have
been reporting peak lead air pollu-
tion values that are many times less
than the quarterly lead NAAQS of
1.5 ug/m3 for a number of consecu-
tive years.
The previous regulation required
that each urbanized area with a
population of 500,000 or more oper-
ate at least two lead National Air
Monitoring Stations (NAMS). The
new rule allows state and local agen-
cies more flexibility. The rule sub-
stantially reduces the requirements
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS
19
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
for measuring lead air pollutant con-
centrations near major highways,
thus shifting the focus to point
sources and their impact on neigh-
boring populations. The regulation
allows states to reduce the number of
NAMS from approximately 85 to
approximately 15. This reduction
will still allow EPA to confirm that
lead air pollution in populated areas
remains well below the NAAQS, but
it refocuses available monitoring
resources into areas with industrial
sources.
Figure 2-13. Long-term ambient Pb trend, 1979-1998.
Concentration, ug/m3
2
1.5
0.5
1979-88 1989-98
(184 sites) (189 sites)
79 81 83 85 87 89 91 93 95 97
Rgure2-14. Trend in Pb maximum quarterly mean concentration by EPA Region, 1989-1998.
.06
f-50%
f 55?
f 33%
Insufficient
Trend Data
.07
f 71%
The National Trend
.09
f 67%
f 57%
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2.
Concentrations are ug/rn3.
Note: These trends are
influenced by the
distribution of monitoring
locations in a given region
and, therefore, can be
driven largely by urban
concentrations. For this
reason, they are not
indicative of background
regional concentrations.
20 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Figure 2-15. Pb maximum quarterly concentration in the vicinity of Pb point sources, 1998.
Rank
1
2
3
4
5
ST
MO
IL
WA
TN
PA
Emission Source
Doe Run (Herculeneum)
Chemetco
Harbor Island Texaco
Refined Metals
Franklin Smelter
Max Qtr Avg.
ua/m3
11.59
2.59
2.03
2.02
1.64
• Exceeds the NAAQS
• Meets the NAAQS
Note: Site markers may overlap
Figure 2-16. Highest Pb maximum quarterly mean by county, 1998.
Concentration (ug/m3)
<0.75
0.75-1.54
1.55-3.04
>= 6.05
CHAPTER 2 • CRITERIA POLLUTANTS —NATIONAL TRENDS 21
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Nitrogen Dioxide
Air Quality Concentrations
1989-98 14% decrease
1997-98 no change
Emissions
1989-98 2% increase
1997-98 1 % decrease
Nature and Sources
Nitrogen dioxide (NO2) is a reddish
brown, highly reactive gas that is
formed in the ambient air through
the oxidation of nitric oxide (NO).
Nitrogen oxides (NOX), the term used
to describe the sum of NO, NO2 and
other oxides of nitrogen, play a major
role in the formation of ozone in the
atmosphere through a complex series
of reactions with volatile organic
compounds (VOCs). A variety of
NOX compounds and their transfor-
mation products occur both naturally
and as a result of human activities.
Anthropogenic (i.e., man-made)
emissions of NOX account for a large
majority of all nitrogen inputs to the
environment. The major sources of
anthropogenic NOX emissions are
high-temperature combustion pro-
cesses, such as those occurring in
automobiles and power plants. Most
of NOX from combustion sources
(about 95 percent) is emitted as NO;
the remainder is largely NO2. Be-
cause NO is readily converted to NO2
in the environment, the emissions
estimates reported here assume nitro-
gen oxides are in the NO2 form. Nat-
ural sources of NOX are lightning,
biological and abiological processes
in soil, and stratospheric intrusion.
Ammonia and other nitrogen com-
pounds produced naturally are im-
portant in the cycling of nitrogen
through the ecosystem. Home heat-
ers and gas stoves also produce sub-
stantial amounts of NO2 in indoor
settings.
Health and Environmental
Effects
Nitrogen dioxide is the most wide-
spread and commonly found nitro-
gen oxide and is a matter of public
health concern. The health effects of
most concern associated with
short-term exposures (i.e., less than
three hours) to NO2 at or near the
ambient NO2 concentrations seen in
the United States, include changes in
airway responsiveness and pulmo-
nary function in individuals with
preexisting respiratory illnesses, as
well as increases in respiratory ill-
nesses in children 5-12 years old.7-8
Evidence suggests that long-term
exposures to NO2 may lead to in-
creased susceptibility to respiratory
infection and may cause alterations
in the lungs. Atmospheric transfor-
mation of NOX can lead to the forma-
tion of ozone and nitrogen-bearing
particles (e.g., nitrates and nitric
acid). As discussed in the ozone and
PM sections of this report, exposure
to both PM and ozone is associated
with adverse health effects.
Nitrogen oxides contribute to a
wide range of effects on public wel-
fare and the environment, including
global warming and stratospheric
ozone depletion. Deposition of nitro-
gen can lead to fertilization, eutrophi-
cation, or acidification of terrestrial,
wetland and aquatic (e.g., fresh water
bodies, estuaries, and coastal water)
systems. These effects can alter com-
petition between existing species,
leading to changes in the number and
type of species (composition) within
a community. For example,
eutrophic conditions in aquatic sys-
tems can produce explosive algae
growth leading to a depletion of
oxygen in the water and/or an in-
crease in levels of toxins harmful to
fish and other aquatic life. Nitrogen
oxides are also important precursors
or components of ozone, particulate
matter and visibility impairment.
(See sections on ozone, particulate
mater, and sulfur dioxide, as well as
chapters on visibility and atmo-
spheric deposition).
Primary and Secondary
Standards
The level for both the primary and
secondary national ambient air quali-
ty standards (NAAQS) for NO2 is
0.053 ppm annual arithmetic average,
not to be exceeded.
National 10-Year Trends
The annual mean NO2 concentration
is the statistic used to track ambient
NO2 air quality trends. A total of 225
ambient NO2 monitoring sites met
the trends data completeness criteria
for the 10-year period 1989-1998.
Figure 2-17 shows that the national
composite annual mean NO2 concen-
tration in 1998 is 14 percent lower
than the composite mean recorded in
1989, and is unchanged from the 1997
level. Except for 1994, annual mean
NO2 concentrations have decreased,
or remained unchanged, each year
since 1989. Figure 2-18 shows how
the trends in annual mean NO2 con-
centrations vary among rural, subur-
ban and urban monitoring locations.
The highest annual mean NO2 con-
centrations are typically found in
urban areas, with significantly lower
annual mean concentrations recorded
at rural sites. The 1998 composite
mean at 80 urban sites is 12 percent
lower than the 1989 level, compared
to an 18-percent reduction at 104
suburban sites. At 39 rural sites, the
22 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS RETORT,
Figure 2-17. Trend in annual NO2 mean concentrations, 1989-1998.
Concentration, ppm
u.u/
0.06
0.05
0.04
0.03
0.02
0.01
0.00
~~
i
i
-
-90th Percentile ^ ~ -' --~ ""„„- ~.. '" "
225 Sites
-Mean
-Median ^, «--.=. ~ — ->. » ,-, - . -,,. - .„. .-,
-1 Oth Percentile N AAQS
.,„
-q
*
i
...„
1
^
.
-—-,
=^^
'l
1
:
— _.,,. ,...
1
— *
1
:
N
'
•i
'{
:k
i&
i
1
;
,f
.-_,..,-,-=, _^-.-..^_i_; *„ .. . . , -..:.,..., .-.-.-.-. ^_=. r. -,-_..-__,._.._-„ _._-_-,. — _-__.,
9'0 91! 9'2 ^3 9'4 9'5 9'6 9'7 9'8
Figure 2-18. Trend in annual mean NO2 concentrations by type of location, 1989-1998.
Concentration, ppm
0.025
o o?
0.015
0.01
0 005
n
,
• • . .
^—- ^^_
^~
Rural (39 sites) Suburban (104 sites) Urban (80 sites)
89 90 91 92 93 94 95 96 97 98
composite mean NO2 concentration
decreased 22 percent from the 1989
concentration level. (See Figure B-3
in Appendix B for a map of the NO2
monitoring site locations.)
Atmospheric concentrations of
NO2 are determined by indirect pho-
tomultiplier measurement of the
luminescence produced by a critical
reaction of NO with ozone. The mea-
surement of NO2 is based first on the
conversion of NO2 to NO, and then
subsequent detection of NO using
this well characterized chemilumi-
nescence technique. This conversion
is not specific for NO^ hence chemi-
luminescence analyzers are subject to
interferences produced by response
to other nitrogen containing com-
pounds (e.gv peroxyacetyl nitrate
[PAN]) that can be converted to NO.
The chemiluminescence technique
has been reported to overestimate
NO2 due to these interferences. This
is not an issue for compliance since
there are no violations of the NO2
NAAQS. In addition, the interfer-
ences are believed to be relatively
small in urban areas.9 .The national
and regional air quality trends de-
picted are based primarily on data
from monitoring sites in urban loca-
tions, and are expected to be reason-
able representations of urban NO2
trends. That is not the case in rural
and remote areas, however, where air
mass aging could foster greater rela-
tive levels of PAN and nitric acid and
interfere significantly with the inter-
pretation of NO2 monitoring data.
Emissions Trends
Figure 2-19 shows the 10-year trend
in NOX emissions. National total
NOX emissions in 1998 are 2 percent
higher than the 1989 total, although
changes in data availability and
methodology between 1989 and 1990
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS
23
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
25,000
20,000
15,000
10,000
5,000
(in the other combustion category)
introduce uncertainty in this compar-
ison. Emissions from electric utility
fuel combustion sources in 1998 are 7
percent lower than the 1989 level,
while emissions from on-road sourc-
es have increased 1 percent during
the past 10 years. Figure 2-20 shows
that the two primary sources of NOX
emissions are fuel combustion and
transportation. Together, these two
sources comprise 95 percent of 1998
total NOX emissions. Title IV (Acid
Deposition Control) of the CAA re-
quired EPA to establish NOX annual
average emission limits for coal-fired
electric utility units in two phases.
NOX reductions are approximately
400,000 tons per year during Phase I
(1996-1999) and two million tons per
year in Phase II (year 2000 and subse-
quent years).!" in 1993,265 Phase I
coal-fired utility units were subject to
the Title IV emission limitations. For
these 265 affected utility units, total
NOX emissions in 1998 were 29 per-
cent lower than in 1990, but 3 percent
higher than in 1997.1° While this is
the second year that NOX emissions
from these sources have increased,
the ascent can be attributed in part to
greater electrical production com-
pared to 1996.W
National 20-Year Trends
As discussed in previous sections of
this report, long-term national ambi-
ent air quality trends are difficult to
assess because few monitoring sites industrial Processes 3.7%
have operated continuously in the
same location for 20 years. Figure
2-21 presents 20-year trends in ambi-
ent NO2 concentrations by combining
two separate 10-year trends databas-
es, 1979-1988 (127 sites) and 1989-
1998 (225 sites). Nationally, annual
mean NO2 concentrations have de-
creased approximately 25 percent
Figure 2-19. Trend in national total NOX emissions, 1989-1998.
Thousand Short Tons Per Year
30,000
Q Fuel Combustion
fj Transportation
| Industrial Processing
I Miscellaneous
89 90 91 92 93 94 95 96 97 98
Figure 2-20. NOX emissions by source category, 1998.
Fuel Combustion 41.7%
Miscellaneous 1.3%
Transportation 53.3%
24 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Figure 2-21. Long-term trend in annual mean NO2 concentrations, 1979-1998.
Concentration, ppm
0.03
0.025
0.02
0.015
0.01
0.005
1979-88 1989-98
(127 sites) (225 sites)
mean NO2 concentration measured in
each county. In July 1998, EPA an-
nounced the redesignation of the
South Coast Air Basin (the last re-
maining nonattainment area for NO2)
to attainment for the NO2 NAAQS."
Data Sources
The NO2 ambient trends plotting
points and emissions totals by source
category are listed in Tables A-l and
A-4, respectively. The plotting points
for the 20-year trend charts are listed
in Table A-9. Table A-ll contains the
highest annual mean NO2 concentra-
tion by county in 1998.
79 81 83 85 87 89 91 93 95 97
since 1979. Annual mean NO2 con-
centrations declined in the early
1980s, were relatively unchanged
during the mid-to-late 1980s, and
resumed their decline in the 1990s.
Because most NO2 monitoring sites
are mobile-source oriented sites in
urban areas, the 20-year decline in
NO2 concentrations more closely
tracks the 19-percent reduction in
NOX emissions from on-road vehicles
since 1980.
Regional Trends
The map in Figure 2-22 shows region-
al trends in NO2 concentrations dur-
ing the past 10 years, 1989-1998
(except Region 10 which does not
have any NO2 trend sites). The
trends statistic is the regional com-
posite mean of the NO2 annual mean
concentrations across all sites with at
least 8 years of ambient measure-
ments. Figure 2-22 shows that the
largest reductions in composite annu-
al mean NO2 concentrations occurred
in the South Coast of California, fol-
lowed by the New England states,
and the northeastern states, New
York and New Jersey. Smaller reduc-
tions in mean NO2 concentrations
were recorded in mid-Atlantic, south-
east, southwest and Rocky Mountain
states. The 1989 and 1998 composite
mean NO2 concentrations were the
same level in both the North Central
and Midwest states.
1998 Air Quality Status
All monitoring locations across the
nation, including Los Angeles, met
the NO2 NAAQS in 1998. This is
reflected on the map in Figure 2-23
that displays the highest annual
CHAPTER 2 • CRITERIA POLLUTANTS — NATIONAL TRENDS 25
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-22. Trend in NO2 maximum quarterly mean concentration by EPA Region, 1989-1998,
Insufficient
Trend Data
.014
•f-7%
.023
f 22%
.016 .016
0%
.020
.015
.014
f.7%
The National Trend
.021
.018
f-14%
Note: These trends are
influenced by the
distribution of monitoring
locations in a given region
and, therefore, can be
driven largely by urban
concentrations. For this
reason, they are not
indicative of background
regional concentrations.
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2. Concentrations are ppm.
Figure 2-23. Highest NO2 annual mean concentration by county, 1998.
100-
170-
1GO-
1SO-
14O-
13O'
120
S 1°°'
Concentration (ppm)
< .0275
.0275 -.0534
26 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Ozone
| Air Quality Concentrations
j 1989-98 4% decrease (1-hr)
|1 no change (8-hr)'
| 1997-98 5% increase (1-hr)
j- 4% increase (8-hr)
Emissions (Anthropogenic VOCs)
1989-98 20% decrease
1997-98
5% decrease
Nature and Sources
Ground level ozone remains a perva-
sive pollution problem in-the United
States. Ozone is readily formed in the
atmosphere by the reaction of VOCs
and NOX in the presence of heat and
sunlight, which are most abundant in
the summer. VOCs are emitted from
a variety of sources including: motor
vehicles, chemical plants, refineries,
factories, consumer and. commercial
products, other industries, and natu-
ral (biogenic) sources. Nitrogen ox-
ides are emitted from motor vehicles,
power plants, and other sources of
combustion, and natural sources
including lightning and biological
processes in soil. Changing weather
patterns contribute to yearly differ-
ences in ozone concentrations. Ozone
and the precursor pollutants that
cause ozone also can be transported
into an area from pollution sources
located hundreds of. miles upwind.
Health and Environmental
Effects
Ozone occurs naturally in the strato-
sphere and provides a protective
layer high above the Earth. Howev-
er, at ground level, it is the prime
ingredient of smog. Short-term (1-3
hours) and prolonged (6-8 hours)
exposures to ambient ozone concen-
trations have been linked to a num-
ber of health effects of concern. For
example, increased hospital admis-
sions and emergency room visits for
respiratory causes have been associ-
ated with ambient ozone exposures.
Exposures to ozone may make
people more susceptible to respira-
tory infection, result in lung inflam-
mation, and aggravate preexisting
respiratory diseases such as asthma.
Other health effects attributed to
short-term and prolonged exposures
to ozone, generally while individuals
are engaged in moderate or heavy
exertion, include significant decreases
in lung function and increased respi-
ratory symptoms such as chest pain
and cough. Children active outdoors
during the summer when ozone lev-
els are at their highest are most at risk
of experiencing such effects. Other
at-risk groups include adults who are
active outdoors, such as outdoor
workers, and individuals with preex-
isting respiratory disorders such as
asthma and chronic obstructive lung
disease. Within each of these groups
are individuals who are unusually
sensitive to ozone. In addition, re-
peated long-term exposure to ozone
presents the possibility of irreversible
changes in the lungs which could
lead to premature aging of the lungs
and/or chronic respiratory illnesses.
Ozone also affects sensitive veg-
etation and ecosystems. Specifically,
ozone can lead to reductions in agri-
cultural and commercial forest yields,
reduced survivability of sensitive tree
seedlings, and increased plant suscep-
tibility to disease, pests, and other
environmental stresses such as harsh
weather. In long-lived species, these
effects may become evident only after
several years or even decades. As
these species are out-competed by
others, long-term effects on forest
ecosystems and habitat quality for
wildlife and endangered species
occurs. Furthermore, ozone injury to
the foliage of trees and other plants
can decrease the aesthetic value of
ornamental species as well as the
natural beauty of our national parks
and recreation areas.
Primary and Secondary 1-hour
Ozone Standards
In 1979, EPA established 1-hour pri-
mary and secondary standards for
ozone. The level of the 1-hour prima-
ry and secondary ozone NAAQS is
0.12 ppm daily maximum 1-hour
concentration that is not to be exceed-
ed more than once per year on aver-
age. To encourage an orderly
transition to the revised ozone stan-
dards (promulgated in 1997; see fol-
lowing section for more information),
EPA initiated a policy in which the
1-hour standards would no longer
apply once an area experienced air
quality data meeting the 1-hour stan-
dards. In 1998 and early 1999, EPA
revoked the 1-hour ozone NAAQS in
2,942 counties in the United States,
leaving 201 counties where the
1-hour standard still applies.12-13/14
However, due to unresolved legal
challenges, the Agency is unable to
enforce and effectively implement the
8-hour standard. As a result, many
areas are without applicable air qual-
ity standards adequate to ensure
public health and welfare. Therefore,
at the tune of publication of this re-
port, EPA has proposed to reinstate
the 1-hour standard nationwide to
alleviate this unanticipated policy
outcome and provide protection of
public health and welfare.-15
Primary and Secondary 8-hour
Ozone Standards
On July 18,1997, EPA established an
8-hour primary ozone standard to
protect against longer exposure peri-
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 27
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
ods that are of concern for both hu-
man health and environmental wel-
fare.'6 The level of the national
8-hour primary and secondary ambi-
ent air quality standards for ozone is
0.08 ppm, daily maximum 8-hour
average over 3 years. The standards
are met when the 3-year average of
the annual fourth-highest daily maxi-
mum 8-hour ozone concentration is
less than or equal to 0.08 ppm.16 In
May 1999, however, the U.S. Court of
Appeals for the D.C. Circuit issued
an opinion concerning the revised
ozone standard. The court remanded
the case back to EPA for further con-
sideration. Following the denial of a
petition for rehearing by the D.C.
Circuit, the Justice Department has
filed a petition for review before the
Supreme Court.
Air Quality Trends
Because the 1-hour and 8-hour
NAAQS have different averaging
times and forms, two different statis-
tics are used m this report to track
ambient ozone air quality trends. For
the 1-hour O3 NAAQS, this report uses
the composite mean of the annual
second-highest daily maximum
1-hour Oa concentration as the statis-
tic to evaluate trends. For the 8-hour
ozone NAAQS, the report relies on
the annual fourth-highest 8-hour daily
maximum O3 concentration as the
statistic of interest to assess trends.
National 10-Year Trends
As shown in Figure 2-24, peak 1-hour
O3 concentrations at 661 monitoring
sites across the country have declined
4 percent over the past 10 years. The
variability among monitoring loca-
tions across the country for this mea-
sure is represented by the 90th
percentile, median, composite mean,
and 10th percentile values. During
Figure 2-24. Trend in annual 2nd-highest daily maximum 1-hour, and 4th-highest daily
8-hour O3 concentrations, 1989-1998.
Concentration, ppm
0.25' "-".rgoth'Percentile~ ~~~ "
0.20
0.15
0.10
0.05
0.00
661 Sites
-Mean
-Median
I_10th Percentile
Annual 2nd Daily 1-Hour Max
Annual 4th Daily 8-Hour Max
89 90 91 92 93 94 95 96 97 98
the past 10 years, values at the sites
with the highest concentrations of the
second daily maximum ozone level
values have continued to decline
more substantially than those at the
sites with average levels of this mea-
sure. While the concentrations at the
more typical sites (composite mean)
are only 4 percent lower in 1998 than
in 1989, the 1-hour ozone levels at
higher concentration sites (the 90th
percentile) declined by 11 percent
during the same period. Although
not shown in a figure, the national
exceedance rate (i.e., the average
number of days when the daily maxi-
mum 1-hour average concentration
exceeds the level of the 1-hour
NAAQS) has declined 62 percent
compared to the rate in 1989. As
noted in previous reports, this statis-
tic, which is simply a count of the
number of times the level of the
NAAQS has been exceeded, can vary
significantly from year to year. Fig-
ure 2-24 also shows the national
trend in 8-hour ozone concentrations
across the same 661 sites. The 8-hour
concentration at typical sites is the
same level in 1998 as observed in
1989. However, the 8-hour ozone
values at the higher concentration
sites (as shown by the 90th percen-
tile) have decreased by 3 percent
since 1989. The trend in the 8-hour _
ozone statistic is similar to the trend
in the 1-hour values, although the
concentration range is smaller.
The maps in Figures 2-25 and 2-26
examine the trend in 1-hour and
8-hour ozone concentrations during
the past 10 years, by geographic re-
gion of the country. For both the
1-hour and 8-hour ozone measure-
ments, trends in the Mid-Atlantic,
Southeast, Central, and Northwest
increased from 1989 to 1998. In addi-
tion/the Southwest region also expe-
rienced an increase over the same
10-year period for the 8-hour ozone
28 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1938
Figure 2-25. Trend in 2nd highest daily 1-hour O3 concentration by EPA Region, 1989-1998.
.122
.107
.116
f 6%
f 12%
.137
f 18%
The National Trend
.114
.110
f 4%
.119
f 3%
.115
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2.
Concentrations are ppm.
Figure 2-26. Trend in 4th highest daily 8-hour O3 concentration by EPA Region, 1989-1998.
.086 .085
f 1%
.093
.088
f. 5%
.092
.084
f 9%
.095
.084
f 12%
85 .087
: The National Trend ;
.086 .086
' no change
Alaska is in EPA Region 1 0; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2.
Concentrations are ppm.
Note: These trends are
influenced by the
distribution of monitoring
locations in a given region
and, therefore, can be
driven largely by urban
concentrations. For this
reason, they are not
indicative of background
regional concentrations.
CHAPTER 2 • CRITERIA POLLUTANTS — NATIONAL TRENDS 29
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
measurement only. The ozone levels
in all other areas followed declining
trends similar to that of the national
observations. These patterns are
generally consistent with, and par-
tially explained by, the meteorologi-
cal conditions experienced during the
1998 summer in these areas. The
summer of 1998 was among the 10
hottest seasons (of the last 100) for
many states within the Southeast,
Southwest and Northwest regions of
the country, and was among the 20
driest summers in the Southeast.
Statewide temperature and precipita-
tion ranks for the summer of 1998 are
shown in Figure 2-27 based on pre-
liminary meteorological data avail-
able from National Oceanic and
Atmospheric Administration
(NOAA).is
In Figure 2-28, the national 1-hour
ozone trend is deconstructed to show
the 10-year change in ambient ozone
concentrations among rural, subur-
ban, and urban monitoring sites. The
highest ambient ozone concentrations
are typically found at suburban sites,
consistent with the downwind trans-
port of emissions from the urban
center. During the past 10 years,
ozone concentrations decreased by 3
percent at 304 suburban sites, and 9
percent at 117 urban sites. However,
at 222 rural sites, 1-hour ozone levels
for 1998 are only 1 percent lower than
the 1989 level and, for the first time,
are greater than the level observed
for urban sites.
Figure 2-29 presents the trend in
8-hour ozone concentrations for 34
Clean Air Status and Trends Network
(CASTNet) sites from 1989-1998.18*
The 8-hour ozone concentrations at
these eastern CASTNet sites, which
were the highest during the hot and
dry summers of 1991 and 1998, have
increased 6 percent over the last 10-
Figure 2-27. Summer 1998 statewide ranks for temperature and precipitation.
Precipitation
Note: For each individual state, the last 104 summers were ranked warmest to coldest and wettest to
driest. A rank of 104 corresponds to the warmest or wettest, while a rank of 1 corresponds to the coldest
or driest. Light gray states are in the warmest or wettest 20 percent of the last 104 years and dark gray
states are in the driest 20 percent. There were no states having ranks in the coldest 20 percent in 1998.
Figure 2-28. Trend in annual 2nd-highest daily maximum 1 -hour O3 concentrations by
location, 1989-1998.
Concentration, ppm
0.20
0.15
0.10
0.05
0.00
Rural (222 sites) Suburban (304 sites) Urban (117 sites)
89 90 91 92 93 94 95 96 97 98
30 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1938
Figure 2-29. Trend in 4*-nighest daily 8-hour O3 based on 34 CASTNet sites in the
rural eastern United States, 1989-1998.
0.25f
0.20
0.15
0.10
0.05J
0.00
Concentration, ppm
-90th Percentile'
A -Mean
'-Median
-10th Percentile
34 Sites
£>2 33 GI4
9'7
year period and 8 percent from 1997-
1998. The CASTNet data complement
the larger ozone data sets gathered by
the State and Local Monitoring
(SLAMS) and National Air Monitoring
(NAMS) networks with additional
rural coverage.
Figure 2-30 further examines pat-
terns in ozone levels by presenting
the 10-year trend in the 8-hour ozone
concentrations across 24 National
Park Service (NFS) sites as well as
specific trends in ambient ozone
levels for each individual site.19
These sites are located in Class I ar-
eas, a special subset of rural environ-
ments (all national parks and
wilderness areas exceeding 5,000
acres) accorded a higher degree of
protection under the CAA provisions
for the prevention of significant dete-
Figure 2-30. Trend in annual 4th-highest daily maximum 8-hour O3 concentrations in National Parks, 1989-1998.
044 ----- .046 .056
.104.
Cape Cod
,.084
Yosemite
Rocky Mtn
.085
.080
; .102.
Shenandoah .1 b?
Brigantine
v.091
Mammoth Cave
.086— ^£^x
.065-:
Grand Canyon
.072
SmokyJMtn,.iio Cape Romain
The National Trerid
.086 .086
no change
Big Bend
.057-
.070
Everglades
.067 '" ~Z .072
••-... Note: Concentrations are ppm.
T Indicates a statistically significant upward trend. Otherwise the trend was not statistically significant.
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS
31
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
rioration. There are more than 24
NFS sites nationally; however, this
analysis focuses on the specific sites
with sufficient data to evaluate
10-year trends. Although the com-
posite mean ozone concentration for
1998 across all 24 sites was un-
changed from the level in 1989, nine
of the NFS sites experienced statisti-
cally significant upward trends in
8-hour ozone levels. Figure 2-30
highlights five such sites: two in the
Great Smoky Mountains National
Park, one in Big Bend National Park,
one hi the Rocky Mountain National
Park, and one in Cape Romain Na-
tional Wildlife Refuge. Although not
statistically significant, the 8-hour
ozone levels at eight of the remaining
15 sites increased between 1989 and
1998, while only three showed down-
ward slopes, and four sites showed
no change. The 1998 levels were
particularly high at the Shenandoah
National Park and the Great Smoky
Mountains National Park. Ozone
levels at these sites were the highest
in a decade and 30-40 percent higher
than the 8-hour ozone standard.
Table A-18 provides data on 10-year
trends in air quality at all 24 NFS
sites.
National 20-Year Trends
Since 1979,1-hour O3 concentrations
have declined 17 percent nationally.
Figure 2-31 clearly shows the peak
ozone years of 1980,1983,1988 and
1995. Because only a few sites have
monitored continuously for two de-
cades, the 20-year trends line in Fig-
ure 2-31 is composed of two
segments—401 sites with complete
data during the first 10 years (1979-
1987) and 661 sites meeting the data
completeness criteria in the most
recent 10 years (1989-1998). It is
important to interpret such long-
Figure 2-31. Trend in annual 2nd-highest daily maximum 1 -hour O3 concentrations,
1979-1998.
Concentration, ppm
0.15
0.1
0.05
1979-88 1989-98
(401 sites) (661 sites)
79 81 83 85 87 89 91 93 95 97
term, quantitative ambient ozone
trends carefully given changes in
network design, siting criteria, spatial
coverage and monitoring instrument
calibration procedures during the
past two decades.
Change Since Last Year
A comparison of the change in 1-hour
ozone concentrations for the two
most recent years of data reveals a
5-percent increase between 1997 and
1998. Similarly, the national 8-hour
ozone concentrations increased 4
percent between 1997 and 1998 (Fig-
ure 2-24). Ambient ozone trends are
influenced by year-to-year changes in
meteorological conditions, popula-
tion growth, changes in emissions
levels from ongoing control measures
as well as the relative levels of ozone
precursors VOC and NOX.
As discussed in previous Trends
Reports, EPA uses a statistical model
to adjust data on the annual rate of
change in ozone from individual
metropolitan areas to account for
meteorological impacts, including
surface temperature and wind
speed.20 Figure 2-32 presents the
composite meteorologically-adjusted
trend in 1-hour average daily maxi-
mum ozone concentrations for 40
metropolitan areas between 1986 and
1998. As seen in this figure, even after
adjusting for meteorological condi-
tions, 1-hour ozone levels in these
selected areas increased slightly more
than 1 percent between 1997 and
1998. This modest one year increase
is within the range of uncertainty of
this analysis and its significance
should not be over interpreted. How-
ever, this increase combined with a
similar rise in adjusted ozone levels
32 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TR&HOS REPORT,
Figure 2-32. Comparison of actual and meteorologically adjusted 1-hour O3 trends,
1989-1998.
Concentration, ppm
0.12
0.11
0.10
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.00
National Trend in annual 2nd max 1 -hr cone. (661 sites)
Avg Daily Max 1hr (40 MSAs)
Met Adj Avg Daily Max 1hr (40 MSAs)
89 90 91 92 93 94 95 96 97 98
Figure 2-33. Areas with PAMS networks.
<^ -.
Providence
Greater Conn.
_v»York
Philadelphia
? Washington
Santa Barb;
Ventura Co.
Los Angelc
San Diego
i :•:.: S
Dallas-Ft. Worth
*"••-. • /
Atlanta ?
--'-•- -.f
I- Areas With PAMS Networks
between 1996 and 1997 (slightly
greater than 1 percent) for these same
areas suggests the beginnings of a
possible upward trend in the ad-
justed statistic which will continue to
be monitored and evaluated in future
analyses and Trends Reports.
The 1-hour ozone concentrations
in urban areas with the most severe
and persistent ozone problems (i.e.,
those classified as extreme, severe,
and serious ozone nonattainment
areas) also increased between 1997
and 1998. This 2-percent increase,
based on data from sites in the areas
required to operate the Photochemi-
cal Assessment Monitoring Stations
(PAMS) network, is consistent with,
but less pronounced than, the 5-per-
cent increase seen nationwide (at the
66110-year trend sites). Currently, 22
of the nation's remaining 32 non-
attainment areas for the 1-hour ozone
NAAQS are required to operate
PAMS sites.21 In addition, although
recently reclassified to attainment for
the 1-hour standard, Boston and
Providence still maintain PAMS sites.
Areas with PAMS networks are
shown in Figure 2-33. Each PAMS
network consists of as many as five
monitoring stations, depending on
the area's population. These stations
are carefully located according to
meteorology, topography, and rela-
tive proximity to emissions sources of
VOC and NOX. As of October 1999,
there were 83 active designated
PAMS sites.
In addition to measuring ozone
levels, PAMS sites include measure-
ments of NOX, total non-methane
organic compounds (TNMOC), a
target list of VOC species including
several carbonyls, plus surface and
upper air meteorology during sum-
mer months when weather condi-
tions are most conducive to ozone
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 33
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
formation. Table 2-3 shows changes
in summer 6:00-9:00 a.m. VOC and
NOX concentrations for selected
PAMS sites.22 Morning periods for
NOX and VOCs are used because
those time frames are generally
thought to be an appropriate indica-
tor of anthropogenic emissions.
Morning NOX concentrations showed
a median decline of 3 percent be-
tween 1997 and 1998 across 60 PAMS
sites. Summer morning VOC concen-
trations registered a median decline
of 7 percent across 45 PAMS sites.
Figure 2-34 presents the median
changes in summer morning concen-
trations of the most abundant VOC
species measured at PAMS sites.
These 23 VOC species are the focus of
this analysis because they account for
more than 75 percent (by volume) of
the VOCs concentrated on in the
PAMS program. Twenty-one of the 23
compounds included showed de-
clines in median values between 1997
and 1998.23
Emissions Trends
Figure 2-35 shows that national total
VOC emissions (which contribute to
ozone formation) from anthropogenic
(man-made) sources decreased 20
percent between 1989 and 1998. Na-
tional total NOX emissions (the other
major precursor to ozone formation)
increased 2 percent over the same
10-year period, although changes in
data availability and methodology
between 1989 and 1990 (in the other
combustion category) introduce un-
certainty in this comparison. Nation-
ally, the two major sources of VOC
emissions are industrial processes (47
percent) and transportation sources
(44 percent) as shown in Figure 2-36.
Solvent use comprises 62 percent of
the industrial process emissions cate-
gory and 29 percent of total VOC
Figure 2-34. The median changes in summer morning concentrations of the most
abundant VOC species? measured at PAMS sites.
Number of Sites
Propane
Isopentane
Toluene
Ethane
n-Butane
n-Pentane
Ethylene
m&p-Xylenes
2-Methylpentane
Isobutane -j
Benzene -I
Acetylene
n-hexane
2,2,4-Trimethylpentane
Kropyiene
3-Methylpentane
1,2,4-Trimethylbenze
o-Xylene
Isoprene
Methylcyolopentane
3-Methylhexane
Ethylbenzene
m-Ethyltoluene
-15
-505
Percent Change
10
15
Notes: 1. The numbers shown in the "Up" and "Down" columns refer to the number of sites in
which the change in summer 6-9 a.m. mean concentrations between 1997 and 1998 is
statistically significant (as determined by a t-test with a significance level of .05). The total
number of sites ("Total") may not equal the sum of the corresponding "Up" and "Down"
categories.
2. Results for Formaldehyde and Acetaldehyde (both carbonyl compounds) were not included in
this analysis. EPA is continuing to assess carbonyl sampling issues to compare these
measurements.
Table 2-3. Summary of 1997-1998 Changes in Summer 6-9 a.m. Mean
1 • I
r-" '•-" ' '
IffNMOC
Total
60
45
Number of Sites
Up
6
6
Down
13
11
I
Median
Change
-3%
-7%
1
•i
Note: The numbers shown in the "Up" and "Down" columns refer to the number of sites
in which the change in summer 6-9 a.m. mean concentrations between 1997 and
1998 is statistically significant. The total number of sites ("Total") may not equal the
sum of the corresponding "Up" and "Down" categories.
emissions. The emissions totals by
source category and year can be
found in Table A-5. Recent control
measures to reduce emissions include
regulations to lower fuel volatility
and to reduce NOX and VOC emis-
sions from tailpipes.24 The effective-
ness of these control measures is
reflected in the 20-percent decrease in
VOC emissions from transportation
sources. VOC emissions from high-
way vehicles have declined 26 per-
cent since 1989, while highway
vehicle NOX emissions have increased
1 percent over the same period.
34 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Figure 2-35. Trend in national total anthropogenic VOC emissions, 1989-1998.
Thousand Short Tons Per Year
r"j Fuel CombustionM Industrial Processing!
Q Transportation B Miscellaneous
89 90 91 92 93 94 95 96 97 98
Figure 2-36. Anthropogenic VOC emissions by source category.
Industrial Processes 47.2%
Fuel Combustion 5.0%
Miscellaneous 4.4%
Transportation 43.5%
Table 2-4. Biogenic sources of VOC
*
r
i
r
••
:
J
Region
Southwestern United States
Northeastern United States
emissions by region.
VOC
Isoprene
Monoterpenes
Isoprene
Monoterpenes
Source
Oak (mostly), citrus,
eucalyptus
Pine, citrus, eucalyptus
Oak (mostly), spruce
i
Maple, hickory, pine,
spruce, fir, cottonwood
As required by the CAA, the Fed-
eral Reformulated Gasoline Program
(RFC) implemented in 1995 has re-
sulted in emissions reductions that
exceed those required by law.25/26
However, the discovery of MTBE
(one of two fuel oxygenates used in
reformulated gasoline to help im-
prove air quality) in the water sup-
plies around the country has required
examination of the approach used in
this program. As previously de-
scribed in the carbon monoxide sec-
tion of this report, in November 1998,
EPA Administrator Carol M. Browner
announced the creation of a blue
ribbon panel of leading experts from
the public health and scientific com-
munities, automotive fuels industry,
water utilities, and local and state
government to review the important
issues posed by the use of MTBE and
other oxygenates in gasoline. The
Panel concluded that RFG provides
considerable air quality improve-
ments and benefits for millions of
U.S. citizens. However, due to
MTBE's persistence and mobility in
water, and its likelihood to contami-
nate ground and surface water, the
Panel recommended that its use in
gasoline be substantially reduced.27
In addition to anthropogenic
sources of VOCs and NOX, there are
natural or biogenic sources of these
compounds as well. Table 2-4 shows
the different predominant plant spe-
cies responsible for VOC emissions in
different parts of the country for two
major biogenic species of concern,
isoprene and monoterpenes. Though
it is not possible to control the level
of these natural emissions, when
developing ozone control strategies,
their presence is an important factor
to consider. Biogenic NOX emissions
are associated with lightning and
biological processes in soil.
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 35
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-37. Highest second daily maximum 1-hour O3 concentration by county, 1998.
Concentration (ppm)
<.065
.165-.204
.125-.164
On a regional basis, biogenic VOC
emissions can be greater than anthro-
pogenic VOC emissions. Biogenic
NOX emissions, on the other hand,
are less than 10 percent of total NOX
emissions.28
1998 Air Quality Status
The map in Figure 2-37 presents sec-
ond highest daily maximum 1-hour
ozone concentrations by county in
1998. The accompanying bar chart to
the left of the map reveals that in
1998 approximately 51 million people
lived in 92 counties where ozone
concentrations were above the level
of the 1-hour ozone NAAQS. These
numbers represent an slight increase
from the totals reported last year (49
million people living in 77 counties)
with ozone concentrations above the
level of the ozone NAAQS in 1997,
As noted previously, meteorological
conditions in some regions of the
country were more conducive to peak
ozone formation in 1998, than in
1997. The map in Figure 2-37 shows
large spatial differences, with higher
ozone concentrations typically found
in Southern California, the Gulf
Coast, and the Northeast and North
Central states. Historically, the high-
est 1-hour concentrations have been
found in Los Angeles and this is
again the case in 1998.
Figure 2-38 presents a map of
fourth highest daily maximum
8-hour ozone values by county in
1998 and an accompanying bar chart
of the number of people in counties
corresponding to various air quality
ranges. The map reveals widespread
areas with high 8-hour ozone concen-
trations (i.e., greater than 0.084 ppm)
in much of the eastern half of the
country and in California as well as
isolated counties in the West. The
corresponding bar chart indicates
that roughly 130 million people live
in counties where fourth highest daily
maximum 8-hour ozone concentrations
were greater than 0.084 ppm.
36 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1938
Figure 2-38. Highest fourth daily maximum 8-hour O3 concentration by county, 1998.
Concentration (ppm)
<.065
.105 - .124
.065 - .084
.125 - .374
5-.104
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 37
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Air Quality Impact of
Major Wildfires
Biomass burning has been recog-
nized as having the potential for
significantly impacting visibility as
well as contributing to elevated am-
bient concentrations of ozone and
particulate matter.1'2 Two severe
wildfire incidents occurred during
1998 that affected ambient concentra-
tions of ozone and particulate matter
in specific areas of the United States.
The first incident occurred late April
to early June in Mexico and Central
America, when thousands of fires of
unusual intensity resulted in elevated
air pollution levels. Figures 2-39 and
2-40 show NASA's images of the
widespread area affected by smoke
plumes that caused elevated pollu-
tion levels mainly for the central
section of the United States. These
images show levels of absorbing
aerosol particles (airborne microscop-
ic dust/smoke) from NASA's Total
Ozone Mapping Spectrometer
(TOMS) instrument. The TOMS data
images have been used increasingly
to understand the behavior of this
material within the atmosphere. The
TOMS is the first instrument to allow
observation of aerosols as the parti-
cles cross the land/sea boundary.
Using these data, it is possible to
observe a wide range of phenomena
such as desert dust storms, forest
fires and biomass burning. In Figure
2-41, the smoke plumes almost two
weeks later have diminished signifi-
cantly from their earlier impacts on
the United States. Guidance was
issued by the Agency to assure that
monitoring data was properly
flagged and effects on air quality are
adequately documented.3
Figure 2-39. Smoke/dust over North America for May 15,1998.
Figure 2-40. Smoke/dust over North America for May 16, 1998.
Figure 2-41. Smoke/dust over North America for May 28, 1998.
38 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1398
Figure 2-42. Smoke/dust over North America for June 22, 1998.
Figure 2-43. Smoke/dust over North American for June 26, 1998.
In late June, a second significant
wildfire incident occurred in Central
Florida and also caused elevated air
pollution levels. Figure 2-42 shows
the areas of Florida affected by the
smoke plumes. These plumes a week
later, as shown in Figure 2-43, were
over the Atlantic Ocean. The State of
Florida worked closely with EPA
regional offices, and the public was
alerted to potential health concerns.
The ambient monitoring data affected
by these fires were also properly
flagged and effects on air quality are
adequately documented.
Ambient concentration data result-
ing from exceptional events, such as
these, are excluded from the trends
analyses and tables in this report
because they are not indicative of
typical air quality levels.
1. Mauzerall, D.L., et al, "Photochemistry in biomass burning plumes and implications for tropospheric ozone
over the tropical South Atlantic," Journal of Geophysical Research, Vol. 103, Number. D7,1998.
2. Andreae, M.O., et al, "Biomass-Burning Emissions and Associated Haze Layers Over Amazonia," Journal of
Geophysical Research, Vol. 93, Number. D2,1988.
3. Memorandum on "Guidance on Assessing the Impacts of May 1998 Mexican Fires on Ozone Levels in the
United States" from John S. Seitz to all Regional Office Directors, 1998.
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS
39
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Particulate Matter
I Air Quality Concentrations (PM10)
I 1989-98 25% decrease 1
1997-98
no change
Emissions (PM10)
1989-98 19% decrease
1997-98
no change
Nature and Sources
Particulate matter (PM) is the general
term used for a mixture of solid parti-
cles and liquid droplets found in the
air. These particles, which come in a
wide range of sizes and shapes, origi-
nate from many different stationary
and mobile sources, as well as from
natural sources. They may be emitted
directly by a source (direct emissions)
or formed in the atmosphere by the
transformation of gaseous precursor
emissions such as SO2 and NOX (sec-
ondary particles). Their chemical
and physical compositions vary de-
pending on location, time of year,
and meteorology.
Health and Environmental
Effects
Scientific studies show a link be-
tween inhalable PM (alone, or com-
bined with other pollutants in the air)
and a series of significant health ef-
fects. Inhalable PM includes both
fine and coarse particles. Fine parti-
cles are those that are less than 2.5
micrometers in diameter. Those be-
tween 2.5 and 10 micrometers are
known as coarse particles. Both
coarse and fine particles can accumu-
late in the respiratory system and are
associated with numerous adverse
health effects. Exposure to coarse
particles is primarily associated with
the aggravation of respiratory condi-
tions such as asthma. Fine particles
are most closely associated with ad-
verse health effects including de-
creased lung function, increased
hospital admissions and emergency
room visits, increased respiratory
symptoms and disease, and prema-
ture death. Sensitive groups that
appear to be at greatest risk to such
PM effects include the elderly, indi-
viduals with cardiopulmonary dis-
ease such as asthma, and children.
Particulate matter also can also
cause adverse impacts to the environ-
ment. Fine PM is the major cause of
reduced visibility in parts of the
United States, including many of our
national parks. Other environmental
impacts occur when particles deposit
onto soils, plants, water, or materials.
For example, particles containing
nitrogen and sulfur that deposit onto
land or water bodies may change the
nutrient balance and acidity of those
environments so that species compo-
sition and buffering capacity change.
An ecosystem condition known as
"nitrogen saturation," where addi-
tions of nitrogen to soil over time
exceed the capacity of the plants and
microorganisms to utilize and retain
the nitrogen, has already occurred in
some areas of the United States.
Particles that are deposited di-
rectly onto the leaves of plants can,
depending on their chemical compo-
sition, corrode leaf surfaces or inter-
fere with plant metabolism. When
deposited in sufficient quantities,
such as near unpaved roads, tilled
fields, or quarries, particles block
sunlight from reaching the leaves,
stressing or killing the plant. Finally,
PM causes soiling and erosion dam-
age to materials, including culturally
important objects such as carved
monuments and statues.
Primary and Secondary PM
Standards
The original standards for PM, estab-
lished in 1971, were for total sus-
pended particulate matter (TSP). In
1987, EPA replaced the TSP standards
with PM10 standards to focus on
smaller particles of aerodynamic
diameter less than or equal to 10
micrometers. These smaller particles
cause greater health concern than
TSP because of their ability to pene-
trate into sensitive regions of the
respiratory tract. The standards for
PM10 include both short- and
long-term NAAQS. The short-term
(24-hour) standard of 150 ug/m3 is
not to be exceeded more than once
per year on average over three years.
The long-term standard specifies an
expected annual arithmetic mean not
to exceed 50 ug/m3 averaged over
three years. These are the primary, or
health-based, PM10 standards. The
secondary, or welfare-based, stan-
dards for PM10 are identical to the
primary standards.
The most recent review of the PM
standards concluded that still more
protection from adverse health effects
was needed. In July 1997, the pri-
mary (health-based) PM standards
were revised to add two new PM2.5
standards, for protection from fine
particles, and to change the form of
the PM10 standards. The new PM2.5
standards were set at 15 ug/m3 and
65 ug/m3, respectively, for the annual
and 24-hour standards.29 The second-
ary (welfare-based) PM2.s standards
were made identical to the primary
standards, and will be implemented
in conjunction with a revised visibil-
ity protection program to address
regional haze in mandatory federal
Class I areas (certain large national
parks and wilderness areas).
40 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Figure 2-44. Trend in annual mean PM10 concentrations, 1989-1998.
Concentration, ug/m3
70
60
50
40
30
20
10
0
-90th Percentile
929 Sites
j -Mean
-Medfaff
_1 Oth Percentile
NAAQS
89 90 91 92 93 94 95 96 97 98
In May 1999, however, the U.S.
Court of Appeals for the D.C. Circuit
issued an opinion concerning the
revised particulate matter standards.
The court vacated the revised PMjo
standard and remanded the PM^.s
standards back to EPA for further
consideration. Following the denial
of a petition for rehearing by the D.C.
Circuit, the Justice Department has
filed a petition for review before the
Supreme Court.
National 10-Year Trends
The first complete year of PM10
trends data for most monitors is 1988.
Therefore, this is only the second
time that the Trends Report has been
able to present a full 10-year air qual-
ity trend for PM10. Figure 2-44 shows
a 25-percent decrease in the average
of annual mean PM10 concentrations
measured at 929 monitoring sites
across the country between 1989 and
1998. The downward trend in PM10
annual means is apparent, with a
leveling off of the trend occurring in
the later years. The final year (1997-
1998) shows no change. This same
general trend can be seen if the sites
are grouped as rural, suburban, and
urban, as in Figure 2-45. The highest
values are generally found at the
urban sites, followed closely by the
suburban sites. The PM10 composite
annual mean is significantly lower at
the rural sites, which are generally
located away from local sources of
PM10.
Several factors have played a role
in reducing PM10 concentrations.
Where appropriate, states required
emissions from industrial sources
and construction activities to be re-
duced to meet the PM10 standards.
Measures were also adopted to re-
duce street dust emissions, including
the use of clean anti-skid materials
like washed sand, better control of
the amount of material used, and
removal of the material from the
street as soon as the ice and snow
melt. Cleaner burning fuels like
natural gas and fuel oil have replaced
wood and coal as fuels for residential
heating, industrial furnaces, and
electric utility and industrial boilers.
Emissions Trends
Nationally,. PM10 direct emissions
decreased 19 percent between 1989
and 1998 (see Figure 2-45). Direct
PM10 emissions are generally exam-
ined in two separate groups. First
there are the more traditionally in-
ventoried sources, shown in Figures
2-46 and 2-47. These include fuel
combustion, industrial processes, and
transportation. Of these, the fuel
combustion category saw the largest
decrease over the 10-year period
(21 percent), with most of the decline
attributable to a decrease in emis-
sions from residential wood burning.
Local control programs to curtail the
use of residential wood heaters dur-
ing times when the air was stagnant
and to replace old woodstoves with
new, cleaner-burning models are
responsible for the decrease in resi-
dential wood burning, along with
lower natural gas and fuel oil prices.
Emissions from the industrial pro-
cesses category decreased 20 percent,
and emissions from the transporta-
tion category decreased 15 percent.
The second group of direct PMjo
emissions is a combination of miscel-
laneous and natural sources includ-
ing agriculture and forestry, wildfires
and managed burning, fugitive dust
from paved and unpaved roads, and
wind erosion. As Figure 2-48 shows,
these miscellaneous and natural
sources actually account for a large
percentage of the total direct PM10
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 41
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
emissions nationwide, although they
can be difficult to quantify compared
to the traditionally inventoried
sources. The trend of emissions in
the miscellaneous/natural group
may be more uncertain from one year
to the next or over several years be-
cause these emissions tend to fluctu-
ate a great deal from year to year.
Table A-6 lists PMjo emissions
estimates for the traditionally inven-
toried sources for 1989-1998. Miscel-
laneous and natural source PM10
emissions estimates are provided in
Table A-7.
Regional Trends
Figure 2-49 is a map of regional
trends for the PM10 annual mean
from 1989-1998. All 10 EPA regions
show decreasing trends over the
10-year period, ranging from 18-38
percent declines. The largest decreas-
es are generally seen in the western
part of the United States. This is sig-
nificant since the two westernmost
regions, 9 and 10, started at the high-
est annual mean concentrations back
in 1989. In the western states, pro-
grams such as those with residential
wood heaters and agricultural prac-
tices have helped reduce emissions of
PM10. Soil moisture levels have also
been higher (from more rainfall) in
many western states in recent years.
In the eastern United States, the Title
IV Acid Rain Program has certainly
contributed to the decrease in PM10
emissions. The program has reduced
SO2 and NOX emissions, both precur-
sors of participate matter in the atmo-
sphere (see Chapter 7 on Atmospheric
Deposition and the SO2 section in this
chapter for more information on the
Acid Rain Program).
Figure 2-45. PM10 annual mean concentration trends by location, 1989-1998.
Concentration, Lig/m3
35
30
25
20
15
10
0
Rural (138 sites) Suburban (355 sites) Urban (413 sites)
89 90 91 92 93 94 95 96 97 98
Figure 2-46. National PM10 emissions trend, 1989-1998 (traditionally inventoried
sources only).
Thousand Short Tons Per Year
4,000
3,000
2,000
1,000
Fuel Combustion B Industrial Processing fj Transportation
89 90 91 92 93 94 95 96 97 98
42 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1S98
Figure 2-47. PM10 emissions from traditionally inventoried source categories, 1998.
Fuel Combustion 38.6%
Industrial Processes 36.0%
Figure 2-48. Total PM10 emissions by source category, 1998.
1998 Air Quality Status
The map in Figure 2-50 displays the
highest second maximum 24-hour
PM10 concentration in each county for
1998. The largest of these was record-
ed in Inyo County, California, caused
by wind blown dust from a dry lake
bed. The bar chart which accompa-
nies the national map shows the
number of people living in counties
within each concentration range. The
Transportation 25.4% colors on the map and bar chart cor-
respond to the colors of the concen-
tration ranges displayed in the map
legend. In 1998, approximately 4
million people lived in 9 counties
where the highest second maximum
24-hour PM10 concentration was
above the level of the 24-hour PM10
NAAQS. When both the annual and
24-hour PM10 standards are consid-
ered, there were 10 million people
living in 13 counties with PM10 con-
centrations above the NAAQS in 1998.
Other Combustion
2.9%
Agriculture & Forestry
14.3%
Wind Erosion 15.3%
Traditionally
Inventoried Sources
8.1%
Fugitive Dust 59.4%
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS
43
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-49. Trend in PM10 annual mean concentration by EPA Region, 1989-1998.
34.3
27.2
•f.38%
33.3
24.4
f.31%
28.8
19.8
41.8
32.1
322
•I- 36%
-f-21%
30.0
28.7
23.3
f 19%
f.18%
" The National Trend
i 31.7
' + 25%
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico,
EPA Region 2. Concentrations are pg/m3.
Note: These trends are
influenced by the
distribution of monitoring
locations in a given region
and, therefore, can be
driven largely by urban
concentrations. For this
reason, they are not
indicative of background
regional concentrations.
Figure 2-50. Highest 2nd maximum 24-hour PM10 concentration by county, 1998.
Concentration (ug/m3).
<55
255-354
fci" "a 55-154
155-254
44 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Fine Particulate Matter
(PM2.5)
Characterizing PM25 Trends
A new monitoring network designed
to assess fine PM data with respect to
the new PM2.5 standards began de-
ployment in early 1999. The status of
this network is shown in Figure 2-51.
As of February 2000, approximately
94 percent of the Federal Reference
Method (FRM) monitoring sites were
operating and 815 of them had al-
ready reported data to EPA's Aero-
metric Information Retrieval System
(AIRS). Once deployment is com-
pleted in December 2000, the net-
work will consist of approximately
1,700 monitors at over 1,100 sites.
These monitors include the mass
monitors (the FRMs), speciation sites,
continuous monitoring sites, and addi-
tional Interagency Monitoring of Pro-
tected Visual Environments
(IMPROVE) sites.
Since this monitoring network
started in 1999, data from another
network, the IMPROVE network of
predominately rural sites, were used
to assess ambient PM2.5 concentra-
tions in this report. Since the moni-
tors in the IMPROVE network are
non-FRM, the data cannot be used for
compliance purposes (i.e., to tell
whether or not an area meets the
PM2.5 standard). They do, however,
provide a good indication of PM25
concentrations and compositions over
broad regions of the country.
The IMPROVE network was estab-
lished in 1987 to track visibility im-
pairment in the nation's most pristine
areas, like national parks and wilder-
ness areas. (The IMPROVE network
is discussed in further detail in Chap-
ter 6: Visibility Trends.) For this rea-
son, the data primarily represent
rural areas. There is, however, one
Figure 2-51. Status of new PM2.5 Monitor Deployment, based on AIRS February, 2000.
Alaska
Hawaii
PM2.5 Monitors
o Data not yet in AIRS<266)
• Data in AIRS (815)
° i-^R-* \Jt~~S
Puerto Rico
urban site (Washington, D.C.) in the
network with adequate trend data.
Data from this site and other sites
meeting data completeness criteria
described in Appendix B, are presented
in this section. Figure 2-52 shows the
location of these sites by region.
1998 Rural PM25 Concentrations
and Composition
Rural PM2 5 concentrations vary re-
gionally. Sites in the east typically
have higher annual mean concentra-
tions. Figure 2-53 shows annual
mean concentrations for 1998 and
reveals the natural break that forms
between the eastern and western
halves of the country. Some compari-
sons can be made between the two
regions. Of the 12 eastern sites, 10
have higher annual averages of mea-
sured PM2 5 than any sites in the
west. In fact, most sites in the west
are roughly less than half of those in
the east. This difference is mainly
due to higher sulfate concentrations
in the east. Sulfate concentrations in
the eastern sites are 4-5 times greater
than those in the western sites. Elec-
tric utilities account for 71 percent of
the SO2 emissions in the eastern
United States. The trend in ambient
sulfates and sulfur dioxides both
appear to generally correspond to the
change in annual sulfur dioxide
emissions from electric utilities in the
eastern United States. In the most
recent year (1997-1998), sulfate con-
centrations increased 10 percent in
the East (as shown later in Figure 2-54).
(Atmospheric deposition of sulfur and
nitrogen compounds is discussed in
further detail in Chapter 7).
The chemical composition of PM2 5
also varies regionally. Sulfate and
organic carbon account for most of
the PM2 5 concentrations in the east
and the west. Sites in the east on
average have a higher percentage of
sulfate concentrations (56 percent)
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 45
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-52. Class I Areas in the IMPROVE Network meeting the data completeness criteria in Appendix B.
Grandpanyon—~*«—^ ""•
\J n MesaWrde-
Petrified Fcgest
Tonto / I
B [Gila Cliff Dwetlin
Cht-lcahua i
-—-3Lj—^~s—'
x\Guadalupe Mountains
V
Big Bend
lehorn
IMPROVE Sites
n Complete for Trends Only
x Complete for 1998 Only
0 Complete for Both
Figure 2-53. Annual average 1998 PM2.5 concentrations (in (jg/ms) at IMPROVE sites and contribution by individual constituents.
Pie chart sizes are scaled by annual average PM2.s concentrations.
3.81
6.821
H Nitrate
B Organic Carbon
Elemental Carbon
Crustal Material
F I Sulfate
46 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-54. PM2.5 Concentrations, 1989-1998 at eastern IMPROVE sites meeting
trends criteria.
Concentration, ug/m3
15
14
11
10
9
8
7
6
5
3 Sites
10 Sites
Measured PM2.5
89 90 91 92 93 94 95 96 97 98
Sulfate
Organic Carbon
Crustal Material
Elemental Carbon
Nitrate
Figure 2-55. PM2.5 Concentrations, 1989-1998 at western IMPROVE sites meeting
trends criteria.
Concentration, ug/m3
6
24 Sites
Measured PM2.5
Organic Carbon
Sulfate
Crustal Material
Nitrate
Elemental Carbon
89 90 91 92 93 94 95 96 97 98
relative to those in the west (33 per-
cent). Table 2-5 shows the difference
in percent contribution of each spe-
cies for the eastern versus western
regions of the United States.
Table 2-5. Percent Contribution to PM2.5
by Component, 1998
«^:
«,;,
gulf ate
|g!emental Carbon
COrganic Carbon
pitrate
| Crustal Material
mi~~:~-—i*~-.-.,--, '•,,-.:.• -_..-
East
56
. . . ' 5
27
5
7
West
- . -. - Ji
. 3? i
" - * 1
36 :
..- ••>!
17 .:
: -- - ' , ^ -•?__.•§
10-Year Trends
Rural
Because of the significant regional
variations in rural PM2.5 concentra-
tions, trends are aggregated by east-
ern and western regions as shown in
Figures 2-54 and 2-55. Based on the
10 sites with trend data in the East,
measured PM2 5 concentrations de-
creased 9 percent between 1992 and
1995, then increased 12 percent from
1995 to 1998. The net change between
1992 and 1998 is a 2 percent increase.
Trends in the West, though, de-
creased 5 percent during the 1992 to
1998 period and decreased 11 percent
over the longer, 10-year period from
1989 to 1998.
Measured mass represents the
direct mass measurement from the
filter. The individual concentrations
do not equal this value because they
do not account for all measured
mass. For more information on the
IMPROVE network, visit
http://alta_vista.cira.colostate.edu/.
Urban
The Washington, D.C. site is not
grouped with the other eastern sites
because it has much higher concen-
trations. Figure 2-56 shows that
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS
47
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
concentrations decreased 5
percent between 1989 and 1997. Data
for this site was incomplete for 1998.
The available, incomplete data indi-
cate that the trend might have in-
creased slightly 1997-1998 consistent
with the eastern rural sites. The ele-
vated levels from 1991 to 1994 are
primarily due to changes in sulfate
concentrations.
Seasonal Trends
Figure 2-57 shows the 1998 seasonal
patterns for PM^s at eastern and
western IMPROVE sites. These sites
were selected to represent typical
patterns across the two regions. Each
square, or tile, represents one day of
the year. The color of each tile corre-
sponds to the daily PM2^ concentra-
tion level. Higher levels are yellow
and orange. The chronological ar-
rangement of daily concentrations
over the course of the year reveals
that summer months typically experi-
ence higher PM2^ concentrations.
Daily concentrations at some sites are
more variable throughout the year
and do not necessarily follow this
pattern as closely. Most western sites
experience few, if any, days with
concentrations above 15 ug/m3,
while most eastern sites regularly
exceed this value in the summertime.
In fact, daily levels at the highest
annual mean site in the west (Big
Bend) are comparable to the second
lowest annual mean site in the east
(Acadia). Both sites had six days
with concentrations above 15 ug/m3
in 1998.
Figure 2-56. PM2.5 Concentrations, 1989-1998, at the Washington, D.C. IMPROVE
site.
Concentration, ug/m3
25
20
15
10
Measured PM2.5
89 90 91 92 93 94 95 96 97
Sulfate
Organic Carbon
Nitrate
Elemental Carbon
Crustal Material
48 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-57. Seasonal patterns in rural PM2.5, 1998.
Concentration (\iglm )
EAST
ACADIA NATIONAL PARK (ME)
1998 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1PZBS
WEDNESDAY
SATURDAY
GREAT SMOKY MOUNTAINS NATIONAL PARK (TN)
1998 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
.rJBsixiJ
WEDNESDAY fe
SATURDAY
OKEFENOKEE NATIONAL WILDLIFE REFUGE (GA)
1998 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
WEDNESDAY!
SATURDAY!
SHENANDOAH NATIONAL PARK (VA)
1998 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
WEDNESDAY!
SATURDAY!
WEST
BIG BEND NATIONAL PARK (TX)
1998 JAN FEB MAR_ AfR MAYJUN JUL AUG SEP OCT NOV DEC
BRYCE CANYON NATIONAL PARK (UT)
1998 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
WEDNESDAYrgj JBBHSBMjiilMBB1111 U1I •n»P~v: •;:•• '• M^MBMMIi^^aMMMi
c"vniprlvYaiii •ll^^™ mssmmnm ^am •• •TTW^ >• i •:.;. mfT^TV^Mi^SfHSmt
MOUNT RAINIER NATIONAL PARK (WA)
1998 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
WEDNESDAYI
SATURDAY!
YOSEMITE NATIONAL PARK (CA)
1998 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
WEDNESDAY!
SATURDAY!
CHAPTER 2 • CRITERIA POLLUTANTS — NATIONAL TRENDS 49
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Sulfur Dioxide
Figure 2-58. Trend in annual mean SO2 concentrations, 1989-1998.
Air Quality Concentrations
1989-98 39% decrease
1997-98
2% decrease
Emissions
1989-98
1997-98
16% decrease
no change
Nature and Sources
Sulfur dioxide (SO2) belongs to the
family of sulfur oxide (SOX) gases.
These gases are formed when fuel
containing sulfur (mainly coal and
oil) is burned, and during metal
smelting and other industrial process-
es. The highest monitored concentra-
tions of SO2 have been recorded in the
vicinity of large industrial facilities.
Health and Environmental
Effects
High concentrations of SO2 can result
in temporary breathing impairment
for asthmatic children and adults
who are active outdoors. Short-term
exposures of asthmatic individuals to
elevated SO2 levels while at moder-
ate exertion may result in reduced
lung function that may be accompa-
nied by symptoms such as wheezing,
chest tightness, or shortness of
breath. Other effects that have been
associated with longer-term expo-
sures to high concentrations of SO2,
in conjunction with high levels of
PM, include respiratory illness, alter-
ations in the lungs' defenses, and
aggravation of existing cardiovascu-
lar disease. The subgroups of the
population that may be affected un-
der these conditions include individ-
uals with cardiovascular disease or
chronic lung disease, as well as chil-
dren and the elderly.
Additionally, there are a variety of
environmental concerns associated
0.04f
Concentration, ppm
0.03
0.02
0.01
o.ool
—_90th Percentile""™
-Mean
-Median
-1 Oth Percentile
482 Sites
NAAQS
89 90 91 92 93 94 95 96 97 98
with high concentrations of SO2.
Because SO2, along with NOX, is a
major precursor to acidic deposition
(acid rain), it contributes to the acidi-
fication of soils, lakes and streams
and the associated adverse impacts
on ecosystems (see Chapter 7, Atmo-
spheric Deposition of Sulfur and
Nitrogen Compounds). Sulfur diox-
ide exposure to vegetation can in-
crease foliar injury, decrease plant
growth and yield, and decrease the
number and variety of plant species
in a given community. Sulfur dioxide
also is a major precursor to PM2.5,
which is of significant concern to
human health (as discussed in the
particulate matter section of this
chapter), as well as a main pollutant
that impairs visibility (see Chapter 6,
Visibility Trends). Finally, SO2 can
accelerate the corrosion of natural
and man-made materials (e.g., con-
crete and limestone) which are used
in buildings and monuments, as well
as paper, iron-containing metals, zinc
and other protective coatings.
Primary and Secondary
Standards
There are both short- and long-term
primary NAAQS for SO2. The
short-term (24-hour) standard of 0.14
ppm (365 ug/m3) is not to be exceed-
ed more than once per year. The
long-term standard specifies an an-
nual arithmetic mean not to exceed
0.030 ppm (80 ug/m3). The second-
ary NAAQS (3-hour) of 0.50 ppm
(1,300 ug/m3) is not to be exceeded
more than once per year.
National 10-Year Trends
The national composite average of
SO2 annual mean concentrations
decreased 39 percent between 1989
and 1998 as shown in Figure 2-58,
with the largest single-year reduction
(16 percent) occurring between 1994
and 1995.30 The trend has since lev-
eled off, declining only 2 percent
from 1997-1998. This same general
trend is seen in Figure 2-59, which
plots the ambient concentrations
grouped by rural, suburban, and urban
50 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-59. Annual mean SO2 concentration by trend location, 1989-1998.
Concentration, ppm
0.012
0.01
0.008
0.006
0.004
0.002
0
Rural (122 sites) Suburban (213 sites) Urban (137 sites)
89 90 91 92 93 94 95 96 97 98
Figure 2-60. Trend in 2nd max 24-hour average SO2 concentrations, 1989-1998.
0.15[
Concentration, ppm
0.10
0.05
O.OGl
NAAQS
r-90th Percentile
-Mean
-Median
-1 Qth Percentile
486 Sites
89 90 91 92 93 94 95 96 97 98
sites. It shows that the mean concen-
trations at the urban and suburban
sites are consistently higher than those
at the rural sites. However, the 1994-
1995 reduction in the concentrations at
non-rural sites does narrow the gap
between the trends. The greater reduc-
tion seen in the non-rural sites reflects
the fact that the proportion of non-rural
sites is greater in the eastern United
States, which is where most of the
1994-1995 emissions reductions at
electric utilities occurred.31 The na-
tional composite second maximum
24-hour SO2 annual mean concentra-
tions decreased 42 percent between
1989 and 1998, as shown in Figure 2-60,
with the largest single-year reduction
(25 percent) occurring between 1994
and 1995. See also Chapter 7, Atmo-
spheric Deposition of Sulfur and
Nitrogen Compounds.
Emissions Trends
National SO2 emissions decreased 16
percent between 1989 and 1998, with
a sharp decline between 1994 and
1995, similar to the decline in the
ambient concentrations. Unlike the
air quality trend, however, the emis-
sions trend begins to climb again
from 1995-1998, as shown in Figure
2-61. This dramatic reduction and
subsequent increase is driven by the
yearly changes in emissions from the
electric utility industry. Much of the
increase was caused by units not yet
affected by the acid rain program.
These units will be in the program
and subject to a national emissions
cap beginning in 2000. The electric
utility industry accounts for most of
the fuel combustion category in Fig-
ure 2-62. In particular, the coal-burn-
ing power plants have consistently
been the largest contributor to SO2
emissions, as documented in Table
A-8 in Appendix A. See also Chapter
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 51
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
7, Atmospheric Deposition of Sulfur
and Nitrogen Compounds.
The Acid Rain Program
The national reductions from 1994r-
1995 in emissions and ambient con-
centrations of SO2 are due mainly to
Phase I implementation of the Acid
Rain Program. Established by EPA
under Title IV of the CAA, the Acid
Rain Program's principal goal is to
achieve significant reductions in SO2
and NOX emissions. Phase I compli-
ance for SO2 began in 1995 and sig-
nificantly reduced emissions from the
participating utilities.32 Table 2-6
shows this reduction in terms of Ta-
ble 1 units (units required to partici-
pate in Phase I) and Non-Table I and
other units. The 1994-1995 decrease
in total SO2 emissions from electric
utilities is due largely to the Phase I
emissions reduction.
Since 1995, however, total SO2
emissions from electric utilities have
increased. Again, Table 2-6 explains
this increase in terms of Table I units
and Non-Table I units. Most Phase I
plants over-complied in 1995, bank-
ing their emission allowances for use
in Phase II, which begins in 2000. As
a result, SO2 emissions have in-
creased slightly at some Phase I
sources since the initial 1995 reduc-
tion. However, Table I units account
for only 18 percent of the total 1995 to
1998 increase. The majority of the
increase is attributed to those units
not yet participating in the Acid Rain
Program. Most of these units will be
included in Phase II of the Program.
When fully implemented, total SO2
emissions from electric utilities will
be capped at 8.95 million tons per
year. For more information on the
Acid Rain Program, visit http://
www.epa.gov/airmarkets. See also
Table 2-6. Total SO2 Emissions from Table I units and Non-Table I units, 1994-1998
(thousand short tons).
1994 1995
Percent Change
1996 1997 1998 1994-951995-98
Phase I units33
Non-Phase 1
7,379
7,510
4,455
7,625
4,760
7,871
4,766
8,324
4,660
8,557
-40
+2
+5
+12
- units
i All Electric 14,889 12,080 12,631 13,090 13,217 -19
~- Utility units
+9
Figure 2-61. National total SO2 emissions trend, 1989-1998.
Thousand Short Tons Per Year
30,000,
25,000
20,000
15,000
10,000
5,000
0
n Fuel Combustion • Industrial Processing
fj Transportation B Miscellaneous
89 90 91 92 93 94 95 96 97 98
Figure 2-62. SO2 emissions by source category, 1998.
Fuel Combustion 85.1%
Miscellaneous 0.1%
Transportation 7.1%
Industrial Processes 7.7%
52 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
1979-88 1989-98
(389 sites) (482 sites)
Figure 2-63. Long-term ambient SO2 trend, 1979-1998.
Concentration, ppm
0.014
0.012
0.01
0.008
0.006
0.004
0.002
0
79 81 83 85 87 89 91 93 95 97
Chapter 7, Atmospheric Deposition
of Sulfur and Nitrogen Compounds.
National 20-Year Trends
The progress in reducing ambient
SO2 concentrations during the past 20
years is shown in Figure 2-63. While
there is a slight disconnect in the
trend line between 1988 and 1989 due
to the mix of trend sites in each
10-year period, an overall downward
trend is evident. The national 1998
composite average SO2 annual mean
concentration is 53 percent lower
than 1979. In addition to the previ-
ously mentioned effects of the Acid
Rain Program, these steady reduc-
tions over time were accomplished
by installing flue-gas control equip-
ment at coal-fired generating plants,
reducing emissions from industrial
Figure 2-64. Trend in SO2 annual arithmetic mean concentration by EPA Region, 1989-1998.
.0066
.0063
f- 29%
f.51%
.0059
.0105
- .0088
.0057
.0023
.0018
f-22%
.0083
f 47%
.0062
.0064
f. 34%
} 24%
The National Trend
.0087
.0053
f 39%
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2.
Concentrations are ppm.
Note: These trends are
influenced by the
distribution of monitoring
locations in a given region
and, therefore, can be
driven largely by urban
concentrations. For this
reason, they are not
indicative of background
regional concentrations.
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 53
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-65. Plants affected by Phase I of the Acid Rain Program.
processing facilities such as smelters
and sulfuric acid manufacturing
plants, reducing the average sulfur
content of fuels burned, and using
cleaner fuels in residential and com-
mercial burners.
Regional Trends
The map of regional trends in Figure
2-64 shows that ambient SO2 concen-
trations are generally higher in the
northeastern United States. The
effects of Phase I of the Acid Rain
Program are seen most vividly in the
northeast. In particular, concentra-
tions fell 20-25 percent between 1994
and 1995 in EPA Regions 1,2,3, and
5. These broad regional trends are
not surprising since most of the units
affected by Phase I of the Acid Rain
Program also are located in the east
as shown in Figure 2-65. This figure
also shows that ambient concentra-
tions have increased slightly between
1995 and 1997 in Regions 3 and 4
where many of the electric utility
units not yet affected by the Acid
Rain Program are located.
1998 Air Qualify Status
The most recent year of ambient data
shows that all counties did meet the
primary SO2 short-term standard,
according to Figure 2-66.
54 CRITERIA POLLUTANTS —NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 2-66. Highest 2nd maximum 24-hour SO2 concentration by county, 1998.
Concentration (ppm)
<.034
.035 - .144
CHAPTER 2 • CRITERIA POLLUTANTS — NATIONAL TRENDS 55
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
References
1. Oxygenated Gasoline Implementation
Guidelines, EPA, Office of Mobile
Sources, Washington, D.C., July 27,
1992.
2. Guidelines for Oxygenated Gasoline
Credit Programs and Guidelines on Estab-
lishment of Control Periods Under Section
211(m) of the Clean Air Act as Amended,
57 FR 47853 (October 20,1992).
3. Interagency Assessment of Oxygenat-
ed Fuels, National Science and Technol-
ogy Council, Executive Office of the
President, Washington, D.C., June
1997.
4. G. Whitten, J. Cohen, and A. Kuk-
lin, Regression Modeling of Oxyfuel Ef-
fects on Ambient CO Concentrations:
Final Report, SYSAPP-96/78, prepared
for the Renewable Fuels Association
and Oxygenated Fuels Association by
System Applications International,
Inc., San Rafael, CA, January 1997.
5. Cook, J. R., P. Enns, and M. S. Sklar,
Regression Analysis of Ambient CO Data
front Oxyfuel and Nonoxyfuel Areas,
Paper No. 97-RP139.02, Air and Waste
Management Association 90th Annual
Meeting, Toronto, Ontario, June 1997.
6. Achieving Clean Air and Water: The
Report of the Blue Ribbon Panel on Oxy-
genates in Gasoline, EPA-420-R-99-021,
U.S. Environmental Protection Agency,
Office of Mobile Sources, Washington,
D.C., September 15,1999 Proposed
Rule," Federal Register, 62 FR 60317,
Washington, D.C., November 7,1997.
7. "National Ambient Air Quality
Standards for Nitrogen Dioxide: Final
Decision," Federal Register, 61 FR 196,
Washington, D.C., October 8,1996.
8. "Review of the National Ambient
Air Quality Standards for Nitrogen
Oxides: Assessment of Scientific and
Technical Information," EPA-452/R-95-
005, U.S. Environmental Protection
Agency, Research Triangle Park, NC,
September 1995.
9. J. H. Seinfeld and S. N. Pandis,
Atmospheric Chemistry and Physics: From
Air Pollution to Climate Change, John
Wiley & Sons, Inc., New York, NY,
1998.
10. "1998 Compliance Report," U.S.
Environmental Protection Agency,
Acid Rain Program, Washington, D.C.,
August 1999.
11. "Approval and Promulgation of
State Implementation Plans and Redes-
ignation of the South Coast Air Basin
in California to Attainment for Nitro-
gen Dioxide; Direct Final Rule," Federal
Register, 63 FR 39747, Washington,
D.C., July 24,1998.
12. "Identification of Ozone Areas
Attaining the 1-hour Standard and to
Which the 1-hour Standard is No
Longer Applicable; Final Rule," Federal
Register, 63 FR 2804, Washington, D.C.,
June 5,1998.
13. "Identification of Additional Ozone
Areas Attaining the 1-hour Standard
and to Which the 1-hour Standard is
No Longer Applicable; Final Rule,"
Federal Register, 63 FR 39431, Washing-
ton, D.C., July 22,1998.
14. "Identification of Additional Ozone
Areas Attaining the 1-hour Standard
and to Which the 1-hour Standard is
No Longer Applicable; Final Rule,"
Federal Register, 64 FR 30911, Washing-
ton, D.C., June 9,1999.
15. "Rescinding Findings that the
1-hour Ozone Standard No Longer
Applies in Certain Areas," Federal
Register, 64 FR 57424, Washington,
D.C., November 5,1999.
16. "National Ambient Air Quality
Standards for Ozone; Final Rule,"
Federal Register, 62 FR 38856, Washing-
ton, D.C., July 18,1997.
17. "Re-Issue of Early Planning Guid-
ance for the Revised Ozone and Partic-
ulate Matter (PM) National Ambient
Air Quality Standards (NAAQS),"
memorandum from S. Shaver, U.S.
Environmental Protection Agency,
Research Triangle Park, NC, June 17,
1998.
18. "Climate Variations Bulletin: Au-
gust 1997," Historical Climatology Series
4-7, Volume 9, Number 8, National
Climatic Data Center, NOAA,
Asheville, NC, September 1997.
18a. CASTNet is considered the na-
tion's primary source for atmospheric
data to estimate dry acidic deposition
and to provide data on rural ozone
levels. Established in 1987, CASTNet
now comprises 79 monitoring stations
across the United States. The longest
data records are primarily at eastern
sites. The majority of the monitoring
stations are operated by EPA's Office of
Air and Radiation; however, 27 sta-
tions are operated by the National Park
Service (NPS) in cooperation with EPA.
A more detailed treatment of CAST-
Net's atmospheric deposition role and
data are provided in Chapter 7: Atmo-
spheric Deposition of Sulfur and Nitro-
gen Compounds.
19. This analysis utilizes a non-para-
metric procedure to assess statistical
significance. A description of this non-
parametric regression procedure is
provided in Chapter 3: Criteria Pollut-
ants—Metropolitan Area Trends.
20. W. M. Cox and S. H. Chu, "Meteo-
rologically Adjusted Ozone Trends in
Urban Areas: A Probabilistic Ap-
proach," Atmospheric Environment, Vol.
27B, No. 4, Pergamon Press, Great
Britain, 1993.
21. "Ambient Air Quality Surveillance:
Final Rule," Federal Register, 58 FR
8452, Washington, D.C., February 12,
1993.
22. "Selected PAMS sites" refers to the
inclusion of only those sites with mea-
surements of NOX or VOC in both
years were used Median changes (in
summer site 6-9 a.m. means) are high-
lighted for NOX and VOC since that
indicator minimizes the greater vari-
ability seen in concentrations of those
parameters in this smaller data set.
23. Although among the top 25 VOC
species (by volume) of the PAMS pro-
gram formaldehyde and acetaldehyde
(both carbonyl compounds) were not
included in this analysis due to lack of
definitive analytic results. Further,
56 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
EPA has evaluating carbonyl sampling
over the past several years and im-
proved measurement protocols will be
issued soon.
24. "Volatility Regulations for Gasoline
and Alcohol Blends Sold in Calendar
Years 1989 and Beyond," Federal Regis-
ter, 54 FR 11868, Washington, D.C.,
March 22,1989.
25. "Reformulated Gasoline: A Major
Step Toward Cleaner Air/' EPA-420-B-
94-004, U.S. Environmental Protection
Agency, Office of Air and Radiation,
Washington, D.C., September 1994.
26. The Clean Air Act requires that
RFC contain 2 percent oxygen by
weight. "Requirements for Reformulat-
ed Gasoline," Federal Register, 59 FR
7716, Washington, D.C., February 16,
1994.
27. The Panel's Executive Summary
and final report entitled "Achieving
Clean Air and Clean Water: The Report of
the Blue Ribbon Panel on Oxygenates in
Gasoline" can be found on the Panel's
homepage at: http://www.epa.gov/
oms / consumer /fuels / oxypanel /
blueribb.htm
28. National Air Pollutant Emission
Trends, 1900-1996, EPA-454/R-97-011,
U.S. Environmental Protection Agency,
Research Triangle Park, NC, 1997.
29. National Ambient Air Quality Stan-
dards for Particulate Matter: Final Rule,
July 18,1997. (62 FR 38652), http://
www.epa.gov/ttn/oarpg/rules.html.
30. The annual mean is used to show
trends in national SO2 air quality be-
cause it is a more stable statistic than
the 24-hour statistic.
31. National Air Pollutant Emissions
Trends Report, EPA-454/R-97-011, US
EPA, Research Triangle Park, NC
27711, December 1997.
32.1937 Compliance Report: Acid Rain
Program, EPA-430-R-98-012, U.S. Envi-
ronmental Protection Agency, Office
of Air and Radiation, Washington,
D.C., August 1998.
33. These data were obtained from the
1998 Emission Scorecard found at
http://www.epa.gov/acidrain/score98/
es!998.htm.
CHAPTER 2
CRITERIA POLLUTANTS — NATIONAL TRENDS 57
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
58 CRITERIA POLLUTANTS — NATIONAL TRENDS • CHAPTER 2
-------
CHAPTER
Criteria Pollutants —
Metropolitan Area Trends
http://www.epa.gov/oar/aqtrnd98/chapter3.pdf
This chapter presents status and
trends in criteria pollutants for Met-
ropolitan Statistical Areas (MSAs) in
the United States. The MSA trends
and status give a local picture of air
pollution and can reveal regional
patterns of trends. Such information
can allow one to gauge the air pollu-
tion situation where they live, al-
though not all areas in the country
are in MSAs, and not all MSAs are
included here. A complete list of
MSAs and their boundaries can be
found in the Statistical Abstract of the
United States.1 The status and trends
of metropolitan areas are based on
four tables found in Appendix A
(A-13 through A-l6). Table A-13 gives
the 1998 peak statistics for all MSAs,
providing the status of the most re-
cent year. Ten-year trends are shown
for the 258 MSAs having data that
meet the trends requirements ex-
plained in Appendix B. Table A-14 lists
these MSAs and reports criteria pollut-
ant trends as "upward" or "down-
ward," or "not significant." These
categories are based on a statistical
test, known as the Theil test, which is
described later in this chapter.
Another way to assess trends in
MSAs is to examine Air Quality In-
dex (AQI) values.2-3 The AQI is used
to present daily information on one
or more criteria pollutants to the
public, in an easily understood for-
mat and in a timely manner. Tables
A-15 and A-16 list the number of
days with AQI values greater than
100 (unhealthy for sensitive groups)
for the nation's 94 largest metropoli-
tan areas (population greater than
500,000). Table A-15 lists AQI values
based on all pollutants, while Table
A-16 lists AQI values based on ozone
alone. The tables listing Pollutant
Standard Index (PSI) data from previ-
ous reports may not agree with the
tables in this report because the new
AQI is completely different. These
changes are presented in more detail
later in this chapter.
For several reasons, these tables
are incomplete with respect to MSAs
and data. For example, not every
MSA appears in the tables and data
for all pollutants does not appear for
each MSA. This is because the MSA
population is so small, or the air
quality is so good, that AQI reporting
is not required. Some data entries in
Table A-13 are listed as "ND," or no
data. Not all criteria pollutants are
measured in all MSAs. Ambient
monitoring for a particular pollutant
may not be conducted if there is no
problem. This is why data for some
MSAs are designated as "ND" (no
data) for those pollutants. In addi-
tion, there are MSAs with too little
monitoring data for trends analysis
purposes (see Appendix B). Finally,
there are MSAs that do not meet the
population threshold required for
inclusion in Tables A-15 and A-16.
Status: 1998
The air quality status for MSAs can
be found in Table A-13 (for related
information, see Table A-12, peak
concentrations for all counties with
monitors that reported to the Aero-
metric Information Retrieval System
(AIRS) database). Table A-13 lists
peak statistics for all criteria pollut-
ants measured in an MSA. Peak
statistics for MSAs are found in Table
A-13, which shows that 173 areas had
peak concentrations exceeding stan-
dard levels for at least one criteria
pollutant. The number of these areas
increased 34 percent over the count
from 1997 data (129 areas). The in-
crease can be attributed to the many
areas that have peak 8-hour ozone
concentrations just above the level of
the 8-hour ozone standard in 1998.
These 173 areas represent 64 percent
of the U.S. population. Similarly,
there were 14 areas representing 14
percent of the population that had
peak statistics that exceeded two or
more standards. Only one area, (Las
Vegas, NV-AZ) representing less than
1 percent of the U.S. population, had
peak statistics from three pollutants
that exceeded the respective stan-
dards. The high value for PM10 is due
to area sources (dust) for this MSA.
CHAPTERS - CRITERIA POLLUTANTS—METROPOLITAN AREA TRENDS 59
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
There were no areas, however, that
violated four or more standards.
Trends Analysis
Table A-14 displays air quality trends
for MSAs. The data in this table are
average statistics of pollutant concen-
trations from the subset of ambient
monitoring sites that meet the trends
criteria explained in Appendix B. A
total of 258 MSAs have at least one
monitoring site that meet these criteria.
As stated previously, not all pollutants
are measured in every MSA.
From 1989-1998, statistics related
to the NAAQS were calculated for
each site and pollutant with available
data. Spatial averages were obtained
for each of the 258 MSAs by averag-
ing these statistics across all sites in
an MSA. This process resulted in one
value per MSA per year for each
pollutant. Although there are sea-
sonal aspects of certain pollutants
and, therefore, seasonality in moni-
toring intensity for different MSAs,
the averages for every MSA and year
provide consistent values with which
to assess trends.
Since air pollution levels are af-
fected by variations in meteorology,
emissions, and day-to-day activities
of populations in MSAs, trends in air
pollution levels are not always well
defined. To assess upward or down-
ward trends, a linear regression was
applied to these data. An advantage
of using the regression analysis is the
ability to test whether or not the up-
ward or downward trend is real (sig-
nificant) or just a chance product of
year-to-year variation (not signifi-
cant). Since the underlying pollutant
distributions do not meet the usual
assumptions required for common
least squares regression, the regres-
sion analysis was based upon a non-
Table 3-1.
F ; ;
i
i
i
|CO
L Lead
f1:
£N°2
kOzone
Sp'zone
t,PM10
fPM10
|'SO2
i SO
i" 2
I
Summary of MSA Trend Analyses, by Pollutant
:: ; : •.-• ;. . •.;-"-.:.. , ":
' ' ' ' ' " '
Trend Statistic
Second Max 8-hour
Max Quarterly Mean
Arithmetic Mean
Fourth Max 8-hour
Second Daily Max 1-hour
Weighted Annual Mean
90th Percentile
Arithmetic Mean
Second Max 24-hour
•• 7">:; -• :, ;:
total #
MSAs
139
90
97
198
198
211
211
148
148
#MSAs
Up
0
1
4
13
11
1
0
0
0
# MSAs
Down
104
61
44
25
23
152
132
103
91
#MSAs
with No
Significant
Change
35
28
49
160
164
58
79
45
57
'
*
i.
1
1
I
t
i
i
*
'k
j
parametric method commonly re-
ferred to as the Theil test.5,6,7 Because
linear regression estimates the trend
from changes during the entire 10-
year period, it is possible to detect an
upward or downward trend even
when the concentration level of the
first year equals the concentration
level of the last year. Also, this
method uses a median estimator
which is not influenced by a single
extreme value.
Table 3-1 summarizes the trend
analysis performed on the 258 MSAs
by pollutant. It shows that there
were no upward trends in carbon
monoxide (CO) and sulfur dioxide
(SO2 maximum daily mean) at any of
the MSAs over the past decade.
Summarized by area, of the 258
MSAs, 221 had downward trends in
at least one of the criteria pollutants,
and only 21 had upward trends. A
closer look at these 21 MSAs reveals
that most are well below the standard
levels for the respective pollutant,
meaning that their upward trends are
not immediately in danger of exceed-
ing the standard levels. The areas
with a significant upward trend that
were near or exceeding a standard
level all involved 8-hour ozone.
Overall, these results demonstrate
significant improvements in urban
air quality over the past decade.
Geographical summaries of the
trends analysis show variations from
one region to another. Trends for CO
show that while most of the nation is
experiencing a downward trend,
there are isolated areas where the
trend is nonsignificant (Southern
Pennsylvania, Washington, Oregon,
Nebraska, Iowa, and Texas). Trends
for lead (Pb) are down for almost all
of the country (one upward trend in
the Seattle area). Trends for NO2 are
either down or nonsignificant with a
small pocket of upward trends in
Texas. Based on the 1-hour ozone -
standard, most MSAs have a nonsig-
nificant trend, with downward trends
showing up in the West (California,
Nevada, and Colorado) and upward
trends showing up in the East.
Trends based on the 8-hour ozone
standard show more areas with 1998
data above the level of the revised
standard. Trends for the annual form
of the PM10 standards show the PM10
60 CRITERIA POLLUTANTS—METROPOLITAN AREA TRENDS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table 3-2. AQI Categories, Colors, and Ranges
Category
PM
PM,
CO (ppm) S02 (ppm) N02 (ppm)
:,. L ,,Q.,-so .^ jj,ij.gqgi-p.og4j, ^^ |
Unhealthy: 151-200 0.105-0.124 0.165-0.204 65.5-150.4 255-354
Very unhealthy 201-300 0.125-0.374 0.205-0.404 150.5-250.4. 355-424
Hazardous
301-400
401-500
0.405-0.504 250.5-350.4
0.505-0.604 350.5-500.4
425-504
505 - 604
12.5-15.4 0.225-0.304 u
15.5-30.4 0.305-0.604 0.65-1.24
30.5-40.4 0.605-0.804 1.25-1.64
40.5-50.4 0.805-1.004 1.65-2.04
1. No health effects information for these levels-use 1-hour concentrations.
2. One hour concentrations provided for areas where AQI based on one hour values might be more cautionary.
3. NO2 has no short term standard but does have a short term "alert" level.
weighted annual mean has mostly
downward trends with the exception
of one area in Pennsylvania. Trends
based on the daily SO2 form of the
standard are mostly down for the
nation. The majority of MSAs with
downward trends are in the northern
half of the nation, while the majority
of the MSAs with non significant
trends are in the southern half of the
nation.
The Air Quality Index
The Air Quality Index (AQI) pro-
vides information on pollutant con-
centrations for ground-level ozone,
particulate matter, carbon monoxide,
sulfur dioxide, and nitrogen dioxide.
The AQI is "normalized" across pol-
lutants so that an AQI value of 100
represents the level of health protec-
tion associated with the national
health-based standard for each pol-
lutant and an AQI value of 500 repre-
sents the level at which the pollutant
causes significant harm . This Index
has been adopted internationally and
is used around the world to provide
the public with information on air
pollutants.
EPA has revised its Air Quality
Index to enhance the public's under-
standing of air pollution across the
nation. Previously known as the
Pollutant Standards Index (PSI), this
uniform air quality index is used by
state and local agencies for reporting
on daily air quality to the public. The
revised Index can also serve as a
basis for programs that encourage the
public to take action to reduce air
pollution on days when levels are
projected to be of concern to local
communities. A new national Internet
website, AIRNOW (www.epa.gov/
airnow), which includes "real time"
air quality data and forecasts of sum-
mertime smog levels in many states,
uses the AQI categories, colors, and
descriptors to communicate informa-
tion about air quality.
AQI values are derived from pol-
lutant concentrations. They are re-
ported daily in all MSAs of the
United States with populations ex-
ceeding 350,000. The AQI is reported
as a value between zero and 500 and
a descriptive name (e.g., "unhealthy
for sensitive groups") and is featured
on local television or radio news
programs and in newspapers.
Based on the short-term NAAQS,
Federal Episode Criteria,8 and Sig-
nificant Harm Levels for each pollut-
ant,? the AQI is computed for PM10,
SC>2, CO, O3, and NO2. Lead is the
only criteria pollutant not included in
the index because it does not have a
short-term NAAQS, a Federal Epi-
sode Criteria, or a Significant Harm
Level. Since the AQI is a tool used to
communicate pollution concerns to a
wide audience, there are also colors
linked to the general descriptors of
air quality. The six AQI color catego-
ries, their respective health effects
descriptors, index ranges, and corre-
sponding concentration ranges are
listed in Table 3-2. EPA has also de-
veloped an AQI logo (Figure 3-1) to
increase the visibility of the AQI in
reports and also alert the public that
the AQI is based on the uniform in-
dex throughout the country.
The AQI integrates information on
criteria pollutant concentrations
across an entire monitoring network
into a single number that represents
the worst daily air quality experi-
enced in an urban area. For each of
the criteria pollutants, concentrations
are converted into an index value
between zero and 500. The pollutant
CHAPTER 3 • CRITERIA POLLUTANTS—METROPOLITAN AREA TRENDS 61
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 3-1. Air Quality Index logo.
Figure 3-2. Number of days with AQI values > 100, as a percentage of 1989 value.
AIR QUALITY INDEX
with the highest index value is re-
ported as the AQI for that day.
Therefore, the AQI does not take into
account the possible adverse effects
associated with combinations of pol-
lutants (i.e., synergism).2<3
An AQI value greater than 100
indicates that at least one criteria
pollutant (NOjhas no short-term
standard) exceeded the level of the
standard, therefore, designating air
quality to be in the "unhealthy for
sensitive groups" range on that day.
Relatively high AQI values activate
public health warnings. For example,
an AQI above 200 initiates a First
Stage Alert at which time sensitive
populations (e.g., the elderly and
persons with respiratory illnesses)
are advised to remain indoors and
reduce physical activity. An AQI over
300 initiates a Second Stage Alert at
which time the general public is ad-
vised to avoid outdoor activity.
EPA has changed the name of the
Pollutant Standards Index to the Air
Quality Index. The revised index
adds an additional air quality cat-
egory just above the level of the stan-
dard. Previously, values from
101-200 were characterized "un-
healthful." The revised index estab-
lishes a category from 101-150
characterized as "unhealthy for sensi-
tive groups," and a category of 151-
200 as "unhealthy."
120
100
20 -
I Southern California All Others
89 90 91 92 93 94 95 96 97 98
When air quality is "unhealthy for
sensitive groups," EPA has added a
corresponding requirement to report
a pollutant-specific statement indicat-
ing what specific groups in the popu-
lation are most at risk. For example,
when the AQI is above 100 for ozone
the AQI report will contain the state-
ment "Children and people with
asthma are the groups most at risk."
To the extent that state and local
agencies use colors to communicate
AQI values, specific colors are re-
quired. For instance, any agency that
chooses to use colors to communicate
such values must represent the Index
values of 151-200 as "red." Examples
of the use of color in Index reporting
include the color bars that appear in
many newspapers, and the color
contours of the ozone map found on
the AIRNOW website.
The revised Index includes a new
sub-index for 8-hour average ozone
concentrations and 24-hour concen-
trations of fine particulate matter.
These changes to the Index are based
on health effects information from the
review of the ozone and particulate
matter standards, as well as informa-
tion and feedback provided by state
and local agencies and the public.
The AQI includes changes to the
sub-indices for 1-hour average ozone
concentrations, particulate matter
(PM10), carbon monoxide and sulfur
dioxide to reflect the addition of the
new air quality category of "un-
healthy for sensitive groups."
Summary of AQI
Analyses
Since an AQI value greater than 100
indicates that the level for at least one
criteria pollutant has reached levels
where people in sensitive groups are
likely to suffer health effects, the num-
ber of days with AQI values greater
than 100 provides an indicator of air
quality in urban areas. Figure 3-2
shows the trend in the number of
days with AQI values greater than
100 summed across the nation's 94
62 CRITERIA POLLUTANTS—METROPOLITAN AREA TRENDS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
largest metropolitan areas as a per-
centage of the 1989 value. Because of
their magnitude, AQI totals for Los
Angeles, Riverside, Bakersfield, and
San Diego are shown separately as
Southern California. Plotting these
values as a percentage of 1989 values
allows two trends of different magni-
tudes to be compared on the same
graph. The long-term air quality
improvement in southern California
urban areas is evident in this figure.
Between 1989 and 1998, the total
number of days with AQI values
greater than 100 decreased 57 percent
in southern California but actually
rose 10 percent in the remaining ma-
jor cities across the United States.
While five criteria pollutants can
contribute to the AQI, the index is
driven mostly by ozone. [Note: NO2 is
rarely the highest pollutant measured
because it is not calculated for AQI
values below 201; and NO2 values in
this range have not been recorded in
the United States for at least five years.]
AQI estimates depend on the
number of pollutants monitored as
well as the number of monitoring
sites where data are collected. The
more pollutants measured and sites
that are available in an area, the bet-
ter the estimate of the AQI for a given
day. Ozone accounts for the majority
of days with AQI values above 100,
but is collected at only a small num-
ber of sites in each area. Table A-16
shows the number of days with AQI
values greater than 100 that are at-
tributed to ozone alone. Comparing
Tables A-15 and A-16, the number of
days with an AQI above 100 are in-
creasingly due to ozone. In fact, the
percentage of days with an AQI
above 100 due to ozone have in-
creased from 92 percent in 1989, to 97
percent in 1998. This increase reveals
that ozone increasingly accounts for
those days above the 100 level and
reflects the success in achieving
lower CO and PMjg concentrations.
However, the typical one-in-six day
sampling schedule for most PMjo
sites limits the number of days that
PM10 can factor into the AQI determi-
nation.
References
1. Statistical Abstracts of the United
States, 1998, U.S. Department of Com-
merce, U.S. Bureau of the Census.
2. Measuring Air Quality, The Pollutant
Standards Index, EPA-451/K-94-001,
U.S. Environmental Protection Agency,
Office of Air Quality Planning and
Standards, Research Triangle Park, NC,
February 1994.
3. Code of Federal Regulations, 40 CFR
Part 58, Appendix G.
4. Note: Although the results are
summarized in the report for compari-
son purposes, the intent of publishing
Tables A-14 through A-16 is to present
information on a localized basis, to be
used on a localized basis (i.e., one MSA
at a time). Therefore, no attempt was
made to adjust the Type I error to a
table-wide basis. All the tests for
trends were conducted at the 5-percent
significance level. No inference has
been made from the tables as a whole.
5. T. Fitz-Simons and D. Mintz, "As-
sessing Environmental Trends with
Nonparametric Regression in the SAS
Data Step," American Statistical Asso-
ciation 1995 Winter Conference, Ra-
leigh, NC, January, 1995.
6. Freas, W.P. and E.A. Sieurin, "A
Nonparametric Calibration Procedure
for Multi-Source Urban Air Pollution
Dispersion Models," presented at the
Fifth Conference on Probability and
Statistics in Atmospheric Sciences,
American Meteorological Society, Las
Vegas, NV, November 1977.
7. M. Hollander and D.A. Wolfe,
Nonparametric Statistical Methods, John
Wiley and Sons, Inc., New York, NY,
1973.
8. Code of Federal Regulations, 40 CFR
Part 51, Appendix L.
9. Code of Federal Regulations, 40 CFR
Part 51, section 51.151.
CHAPTERS • CRITERIA POLLUTANTS—METROPOLITAN AREA TRENDS 63
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
64 CRITERIA POLLUTANTS—METROPOLITAN AREA TRENDS • CHAPTERS
-------
CHAPTER
Criteria Pollutants —
Nonattainment Areas
This chapter provides general infor-
mation on geographical regions
known as nonattainment areas.
When an area does not meet the air
quality standard for one of the crite-
ria pollutants the area may be subject
to the formal rule-making process
which designates the area as non-
http://www.epa.gov/oar/aqtrnd98/chapter4.pdf
attainment. The 1990 Clean Air Act
Amendments (CAAA) further classi-
fy ozone, carbon monoxide, and
some particulate matter nonattain-
ment areas based on the magnitude
of an area's problem. Nonattainment
classifications may be used to specify
what air pollution reduction mea-
sures an area must adopt and when
the area must reach attainment. The
technical details underlying these
classifications are discussed in the
Code of Federal Regulations, Part 81 (40
CFR 81), see http://www.epa.gov/
epacfr40.
Figure 4-1. Location of nonattainment areas for criteria pollutants, September 1999.
GUAM
j O Pit! Power Plant
j O Tanguisson Power Plant
Note: Incomplete data, not classified, and Section 185(a) areas are not shown.
"Ozone nonattainment areas on map are based on the pre-existing ozone standard.
**PM10 nonattainment areas on map are based on the pre-existing PM10 standards.
Nonattainment designations based on the revised PM10 standards have not been made.
CHAPTER 4
CRITERIA POLLUTANTS — NONATTAINMENT AREAS 65
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 4-2. Classified ozone nonattainment areas where 1-hour standard still applies.
Classifications
Extreme (LA) & Severe m Serious • Moderate • Marginal
Note: San Francisco is classified Other / Sec 185A & incomplete data areas not included.
Figure 4-1 shows the location of
the nonattainment areas for each
criteria pollutant as of September
1999. Figure 4-2 identifies the classi-
fied ozone nonattainment areas by
degree of severity. A summary of
nonattainment areas can be found in
Table A-17 in Appendix A. This con-
densed list is located on the Internet
at http://www.epa.gov/airs/
nonattn.html and is updated as ar-
eas are redesignated. An area is on
the condensed list if the area is desig-
nated nonattainment for one or more
of the criteria pollutants. Note that
Section 185a areas (formerly known
as "transitional areas") and incom-
plete areas are excluded from the
counts in Table A-17. Another source
of information for areas designated
as nonattainment, including Section
185a and incomplete areas, is the
Green Book. The current Green Book
is located at http://www.epa.gov/oar/
oaqps/greenbk.
As of September 1999, there were
a total of 121 nonattainment areas on
the condensed nonattainment list.
The areas on the condensed list are
displayed alphabetically by state.
There were, as of September 1999, .
approximately 105 million people
living in areas designated as non-
attainment for at least one of the
criteria pollutants. Areas redesig-
nated between September 1998 and
September 1999 are listed in Table
4-1, by pollutant. All redesignations
were to attainment except for the Fort
Hall Indian Reservation Area which
was designated to nonattainment for
PM10. Subsequent to the 1997 O3
National Ambient Air Quality Stan-
dards (NAAQS) revision, EPA re-
voked the 1-hour O3 NAAQS in U.S.
counties with three years of clean air
quality.1/2 Nonattainment areas that
had the 1-hour 0% standard or the
PMjo standard revoked between
September 1998 and September 1999
are listed in Table 4-2. Because of
pending legal challenges, the EPA is
not able to enforce the 8-hour stan-
dard resulting in many areas without
applicable air quality standards. At
the time of report publication, the
Agency has proposed to reinstate the
1-hour standard.3 The present status
of nonattainment areas compared to
the status after nonattainment desig-
nations resulting from the CAAA is
shown in Table 4-3.
66 CRITERIA POLLUTANTS — NONATTAINMENT AREAS • CHAPTER 4
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Table 4-1. Areas Redesignated Between September 1998 and September 1999
; SO2 Muhlenberg Co., Ky; Lake Co., OH and Jefferson Co., OH
i-: ' •
!; PM-io Fort Hall Indian Reservation, ID
tuCO Connecticut portion of New York-N. New Jersey-Long Island, NY-NJ-CT
;»._
| Pb Muscogee Co., Ga and Williamson Co. (Nashville), TN
| Oa The number of O3 areas remained the same between September 1998
? -. and September 1999.
Table 4-2. Revocations of Nonattainment Areas Only Between September 1998 and
September 1999
03
Boston-Lawerence-Worcester, MA-NH
Muskegon, Ml
Providence, Rl
PM10
Boise, ID
Portsmouth-Dover-Rochester, NH
Portland, ME
Door Co., WI
References
1. "Identification of Ozone Areas
Attaining the 1-Hour Standard and to
Which the 1-Hour Standard Is No
Longer Applicable; Final Rule," Federal
Register, 63 FR 2804, Washington, B.C.,
June 5,1998.
2. "Identification of Additional Ozone
Areas Attaining the 1-Hour Standard
and to Which the 1-Hour Standard Is
No Longer Applicable; Final Rule,"
Federal Register, 63 FR 39431, Washing-
ton, D.C., July 22,1998.
3. "Rescinding Findings that the
1-hour Ozone Standard No Longer
Applies in Certain Areas," Federal
Register, 64 FR 57424, Washington,
B.C., November 5,1999.
Table 4-3. Nonattainment Status
Pollutant
CO
Pb
N02
03
PMio
SO2
Original
# areas
43
12
1
101
85
51
1999
# areas
20
8
0
32
77
31
1999
Population
(in 1000s)
33,230
1,116
0
92,505
29,880
4,371
CHAPTER 4
CRITERIA POLLUTANTS — NONATTAINMENT AREAS 67
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
68 CRITERIA POLLUTANTS —NONATTAINMENT AREAS • CHAPTER 4
-------
CHAPTER
Air Toxics
http://www.epa.gov/oar/aqtrnd98/chapter5.pdf
Background
Hazardous air pollutants (HAPs)/
commonly referred to as air toxics or
toxic air pollutants are pollutants
known to cause or suspected of caus-
ing cancer or other serious human
health effects or ecosystem damage.
Section 112 of the CAA now lists 188
pollutants or chemical groups as
HAPs and targets sources emitting
them for regulation.1 Examples of air
toxics include heavy metals like mer-
cury and chromium and organic
chemicals like benzene, 1,3-butadi-
ene, perchloroethylene ("perc"),
dioxins, and polycyclic organic mat-
ter (POM).
Hazardous air pollutants (HAPs)
are emitted from literally thousands
of sources including large stationary
industrial facilities or major point
sources (such as electric power plants
or utilities), smaller area sources
(such as neighborhood dry cleaners),
and mobile sources (such as automo-
biles). Adverse effects to human
health and the environment due to
HAPs can result from exposure to air
toxics from individual facilities, ex-
posure to mixtures of pollutants
found in urban settings, or exposure
to pollutants emitted from distant
sources that are transported through
the atmosphere over regional, na-
tional or even global airsheds. Expo-
sures of concern to HAPs can be
either short-term or long-term in
nature. In addition to breathing air
contaminated with air toxics, expo-
sure to some HAPs can occur by
other means, such as through the
ingestion of contaminated food from
waters polluted from the deposition
of HAPs. Some HAPs can bioaccu-
mulate in body tissues. When a
predator feeds on contaminated prey,
concentrations of these bioaccumula-
tive HAPs can build up in the
predator's tissues, magnifying the
toxic burden. As of December 1998,
over 2,506 U.S. water bodies are un-
der fish consumption advisories (for
particular species of fish), represent-
ing approximately 15.8 percent of the
nation's total lake acreage and 6.8
percent of the nation's river miles.2
Health and Environmental
Effects
Most of the information on potential
health effects of HAPs is derived
from experimental animal data and
studies of exposed workers. The
different health effects which may be
caused by HAPs include cancer, neu-
rological, cardiovascular, and respira-
tory effects, effects on the liver, •
kidney, immune system, and repro-
ductive system, and effects on fetal
and child development. The timing
of effect and the severity (e.g., minor
or reversible vs. serious, irreversible,
and life-threatening) may vary
among HAPs and with the exposure
circumstances. In some rare cases,
effects can be seen immediately. Rare
cases involve the catastrophic release
of lethal pollutants, such as the 1984
incident in Bhopal, India, where
more than 2,000 people were killed
by the release of methyl isocyanate
into the atmosphere. In other cases,
the resulting effects (e.g., liver dam-
age or cancer) are associated with
long-term exposures and may not
appear until years after exposure.
More than half of the 188 HAPs have
been classified by EPA as "known,"
"probable," or "possible" human
carcinogens. Known human carcino-
gens are those that have been demon-
strated to cause cancer in humans.
Examples include benzene, which
has caused leukemia in workers ex-
posed over several years to certain
amounts of it in their workplace air,
and arsenic, which has been associat-
ed with elevated lung cancer rates in
workers at metal smelters. Probable
and possible human carcinogens
include chemicals that are less certain
to cause cancer in people, yet for
which laboratory animal testing or
limited human data indicates carci-
nogenic effects.
Some HAPs pose particular haz-
ards to people of a certain age or
stage in life (e.g., young children,
adolescents, adults, or elderly
people). Available data suggest that
CHAPTER 5
AIR TOXICS 69
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
about a third of HAPs, may be devel-
opmental or reproductive toxicants in
humans. This means that exposure
during the development of a fetus or
young child may prevent normal
development into a healthy adult.
Other such critical exposures may
affect the ability to conceive or give
birth to a healthy child. Ethylene
oxide, for example, has been associ-
ated with increased miscarriages in
exposed workers and has affected
reproductive ability in both male and
female laboratory animals.
Toxic air pollutants can have a
variety of environmental impacts in
addition to the threats they pose to
human health. Animals, like humans,
may experience health problems if
they breathe sufficient concentrations
of HAPs over time, or ingest HAPs
through contaminated food (e.g.,
fish). Apart from the laboratory test-
ing results on animal species that
make up a large portion of the hu-
man health effects database, and
aquatic toxicity criteria for some
HAPs, little quantitative information
currently exists to describe the nature
and scope of the effects of ah- toxics
on non-human species.
One of the more documented eco-
logical concerns associated with
toxic air pollutants is the potential for
some HAPs to damage aquatic eco-
systems. For example, a number of
studies suggest that deposited air
toxics contribute to deleterious effects
such as reproductive failures, devel-
opmental disorders, disease, and
premature death in fish and wildlife
species native to the Great Lakes.
Deposited air pollutants can be sig-
nificant contributors to overall pollut-
ant loadings entering water bodies
(especially for persistent chemicals
such as mercury which continue to
move among air, water, and sedi-
ments). For the Great Lakes, interna-
tional programs have examined the
importance of deposition of air toxics,
relative to other loadings such as
direct discharge. While data are
presently insufficient for many quan-
titative estimates comparing air
deposition and other loading path-
ways, deposition of air toxics to the
Great Lakes is considered significant
and continues to be investigated with
a binational monitoring network, the
Integrated Atmospheric Deposition
Network (IADN).3
Persistent air toxics are of particu-
lar concern in aquatic ecosystems, as
toxics levels can magnify in the food
web, resulting in exposures greater
than those expected based solely on
the levels in water or air. Such "bio-
accumulation" and "biomagnification"
(where the levels of a toxic substance
increase at higher trophic levels of
the food web) are seen in New En-
gland populations of breeding loons,
birds that feed on fish in waters con-
taminated by airborne mercury: Stud-
ies are showing that an estimated
12-31 percent of the breeding loons
have mercury levels that put them at
risk of behavioral, reproductive and
other effects.4
National Air Toxics Control
Program (The Regulatory
Response)
In 1990, Congress amended the CAA
by adding a new approach to the
regulation of HAPs. This new ap-
proach is divided into two phases.
The first requires the development of
technology-based emissions stan-
dards for stationary sources of the
188 HAPs. The second phase is to
evaluate remaining problems or risks
and develop additional regulations to
address sources of those problems, as
needed.
Phase One is composed of the
technology-based standards, known
as MACT (Maximum Achievable
Control Technology) and GACT
(Generally Achievable Control Tech-
nology) regulations, under Sections
112(d). All large, or major, sources of
the 188 HAPs must be addressed by
MACT or GACT regulations, as well
as the smaller, area sources found to
carry significant risk or identified as
important under the Specific Pollut-
ants Strategy [Section 112(c)(6)] or the
urban program [Sections 112(c)(3)
and 112(k)]. Some combustion
sources, such as municipal waste
combustors and medical waste incin-
erators, are regulated under equiva-
lent requirements in Section 129. The
purpose of this technology-based
approach is to use available control
technologies or changes in work
practices to get emission reductions
for as many of the listed HAPs as
possible. It is intended that effective
MACT standards will reduce a ma-
jority of the HAP emissions and,
therefore, reduce potential risks from
regulated sources.
Air toxics emission reductions also
result from the particulate matter,
ozone and carbon monoxide control
programs which are directed at both
stationary and mobile sources (see
emission reductions described in
Chapter 2). While the toxic reduc-
tions from EPA's mobile source emis-
sion standards have been large, prior
to 1990, EPA had no specific direc-
tions from Congress for a planned
program to control toxic emissions
from mobile sources. However in
1990, Congress amended the CAA by
adding a formal requirement to con-
sider motor vehicle air toxics controls
under Section 202(1). Section 202(1),
required the Agency to complete a
study of motor vehicle-related air
70 AIR TOXICS • CHAPTER 5
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table 5-1. List of 33 Urban Air Toxics Strategy HAPs
VOCs
acrylonitrile
benzene
Metals
(Inorganic
Compounds)
arsenic compounds
beryllium and compounds
Aldehydes
(Carbonyl
Compounds)
acetaldehyde
formaldehyde
SVOCs &
Other HAPs
2,3,7,8-tetrachlorodi
benzo-p-dioxin (&
congeners & TCDF
congeners)
coke oven emissions
cadmium compounds acrolein
chromium compounds
lead compounds
manganese compounds
mercury compounds
nickel compounds
1,3-butadiene
carbon tetrachloride
chloroform
1,2 -dibromoethane
(ethylene dibromide)
1,3-dichloropropene
1,2-dichloropropane
(propylene dichloride)
ethylene dichloride, EDO
(1,2-dichlorethane)
ethylene oxide
methylene chloride
(dichloromethane)
1,1,2,2,-tetrachloroethane
tetrachloroethylene
(perchloroethylene, PCE)
trichloroethylene, TCE
vinyl chloride
toxics, and to promulgate require-
ments for the control of air toxics
from motor vehicles. EPA completed
the required study in 1993, and is
presently conducting analyses to
update emissions and exposure
analyses done for the study as well as
working on rulemaking to address
the requirements of the section.
After application of the technol-
ogy-based standards comes Phase
Two, which consists of strategies and
programs for evaluating remaining
risks and ensuring that the overall
program has achieved a sufficient
reduction in risks to public health
hexachlorobenzene
hydrazine
polycyclic organic matter
(POM)
polychlorinated biphenyls
(PCBs)
quinoline
and the environment. This phase will
be implemented through such pro-
grams as the integrated urban air
toxics strategy, and the residual risk
program (Section 112(f)). The inte-
grated urban air toxics strategy iden-
tifies 33 HAPs which are judged to
pose the greatest threat to public
health in urban areas.5 The strategy
requires that EPA ensure a 75-percent
reduction in cancer incidence from
stationary sources; a "substantial"
reduction in non-cancer risks from
area sources; and to also ensure that
disproportionate risks are addressed
first by focusing efforts on sensitive
populations or geographic hot spots.
In addition, the strategy must assure
that area sources accounting for 90
percent of the total emissions of the
urban HAPs are subject to MACT or
GACT regulations. The list of the 33
urban HAPs are presented in Table
5-1 and are grouped according to
their chemical properties [volatile
organic compounds (VOCs), metals,
aldehydes, and semi-volatile organic
compounds (SVOCs)]. This list in-
cludes not only those with emissions
from area sources, but also includes
those posing public health concerns
in urban areas regardless of emission
source type.
Phase Two also will use informa-
tion generated through the special
studies required in the CAA—the
Great Waters program [Section 112(m)],
and the Mercury and Utility Studies
[Section 112(n)]. The Great Waters
program contains an ongoing exami-
nation of atmospheric deposition of
air toxics to aquatic ecosystems, and
the effects of those toxics when con-
centrated through the food web. The
Mercury Study examined the adverse
effects of, and possible controls for,
mercury from all sources. The Utility
Study examined health hazards of,
and possible controls for, the numer-
ous toxics from electric utilities.
The CAA recognizes that not all
problems are national problems or
have a single solution. Authority for
national emission standards are
complemented by authorities to ex-
amine problems on other scales in
order to address specific concerns.
The CAA also provides mechanisms
for increasing partnerships among
EPA, states and local programs to
address problems specific to these
regional and local environments. As
we move toward the 21st century,
EPA's National Air Toxics Program is
CHAPTER 5
AIR TOXICS
71
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
beginning to progress from the more
technologically-based approach for
regulating toxics to a more risk-based
approach. This shift will require
more and better information about all
emission sources of HAPs, ambient
levels of HAPs, and human and eco-
system exposure to HAPs. The de-
velopment of an "information
infrastructure" to inform the risk-
based decisions has been a priority
for the EPA over the last few years.
National Air Toxics
Assessment Activities
The success of the National Air Tox-
ics Program critically depends on
our ability to quantify the impacts of
air toxics emissions on public health
and the environment. To that end,
EPA has initiated numerous National
Air Toxics Assessment (NATA) activi-
ties to help identify areas of concern,
characterize risks and track progress.
These activities include expanded air
toxics monitoring, improving and
periodically updating emissions
inventories, national- and local-scale
air quality and exposure modeling,
and continued research on effects and
assessment tools. NATA activities
will lead to improved characteriza-
tions of air toxics risk and reductions
in risk resulting from ongoing and
future implementation of air toxics
emissions control standards and
initiatives. A major assessment is
currently underway at EPA which
will address the 188 HAPs. It in-
cludes state-by-state updates to emis-
sion inventories for the year 1996,
known as the National Toxics Inven-
tory (NTI), and nationwide estima-
tion of air quality using the ASPEN
(Assessment System for Population
Exposure Nationwide) air quality
dispersion model. Together with the
Hazardous Air Pollutant Exposure
Model (HAPEM4), the NATA nation-
al-scale screening assessment will
also be used to estimate 1996 popula-
tion exposures across the nation, and
characterize potential public health
risks due to inhalation of air toxics,
including both cancer and noncancer
effects. Although the NTI includes all
188 pollutants, the initial modeling
activities focus on the "urban HAP
list" (Table 5-1).
Ambient Monitoring
Ambient air toxics monitoring is
another important component of
NATA. Ambient measurements are
useful to: characterize ambient con-
centrations and deposition in repre-
sentative monitoring areas, provide
data to support and evaluate disper-
sion and deposition models, and
establish trends and evaluate the
effectiveness of HAP reduction strat-
egies. There are approximately 300
monitoring sites currently producing
ambient data on hazardous air pol-
lutants. EPA is working together with
state and local air monitoring agen-
cies to build upon these monitoring
sites to develop a monitoring net-
work which is representative of air
toxics problems on a national scale
and which provides a means to ob-
tain data on a more localized basis as
appropriate and necessary. The net-
work will represent an integration of
information from many monitoring
programs, including PAMS, which
provide information on VOCs and
aldehydes, and the new urban PM2.5
chemical speciation and rural IM-
PROVE networks which provide
information on HAP trace metals.
This new national network will be
developed over the next several
years. Trend data will initially be
used to help characterize air quality,
and to support and evaluate models
and later to better describe national
HAP trends.^
Several states have long-standing
air toxics monitoring programs which
already produce measurements on
many HAPs including the important
urban HAPs. Some of these state
programs are assisted by EPA's con-
tractor-supported Urban Air Toxics
Monitoring Program (UATMP), as
well as the Non-Methane Organic
Compound (NMOC) and Speciated
Non-Methane Organic Compound
(SNMOC) monitoring programs. The
UATMP is dedicated to toxics moni-
toring which involves measurements
of 39 HAP VOCs and 13 carbonyl
compounds.7 The Agency's Photo-
chemical Assessment Monitoring
Stations (PAMS) also measure HAPs
among the many pollutants that are
precursors of ozone.
The PAMS program requires rou-
tine year-round measurement of
VOCs which include nine HAPs:
acetaldehyde, benzene, ethylbenzene,
formaldehyde, n-hexane, styrene,
toluene, xylenes (m/p-xylene,
o-xylene) and 2,2,4-trimethlypentane.
Three of these are on the list of urban
HAPs (acetaldehyde, benzene and
formaldehyde). For a more detailed
discussion of the PAMS program, see
the ozone section in Chapter 2 of this
report. Although the state air toxics
and PAMS data are limited in their
geographic scope, they do not cover
many HAPs for most states, and are
not necessarily sited to represent the
highest area-wide concentrations,
they can still be used to provide use-
ful information on the trends in ambi-
ent air toxics at this time.
72 AIR TOXICS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table 5-2. Comparison of Typical Urban and Rural Concentrations for VOCs and Aldehydes, Based on 1996 Ambient Measurements
Urban Sites
Rural Sites
Urban to Rural
HAP
1 ,2-Dibrornoethane
Ethylene dichioride
Styrene
Trichloroethylene
Vinyl chloride
1 ,2-Dichloropropane
Tetrachloroethylene
1 ,3-Butadiene
1,1 ,2,2-Tetrachloroethane
trans-1 ,3-Dichloropropene
; Methylene chloride
, cis-1 ,3-Dichloropropene
Chloroform
Carbon tetrachloride
Acrolein
Toluene
Benzene
Formaldehyde
Acetaldehyde
Table 5-3. Comparison of Typical
Number
of sites
ug/m3
60
88
74
84
86
52
90
60
32
10
95
10
94
86
24
101
121
38
38
Urban and
Annual Average
Concentration,
ug/m3
0.70
0.40
1.75
0.62
0.31
0.30
1.17
0.84
0.09
0.03
1.40
0.03
0.47
0.89
0.20
5.68
2.08
5.17
2.94
Rural Concentrations
Urban Sites
HAP
Nickel (fine)
i Cadmium (pm10)
Arsenic (fine)
Lead (fine)
Manganese (fine)
Lead (coarse)
Nickel (pm10)
Nickel (tsp)
Manganese (pm10)
Chromium (coarse)
Chromium (pm10)
; Beryllium (tsp)
; Chromium (tsp)
Nickel (coarse)
Chromium (fine)
Lead (pm10)
Manganese (coarse)
Chromium VI
Arsenic (pm10)
', Arsenic (coarse)
Beryllium (pm10)
Mercury (coarse)
Mercury (fine)
Manganese (tsp)
Mercury (pm10)
; Mercury (tsp)
Arsenic (tsp)
: Lead (tsp)
Cadmium (tsp)
Number
of sites
ng/m3
13
12
13
13
13
13
24
88
20
13
25
31
90
13 .
13
40
13
27
25
13
7
13
13
71
17
35
73
296
80
Annual Average
Concentration,
ng/m3
1.14
1.65
1.05
4.70
3.34
.3.15
3.65
10.53
13.67
2.25
6.14
0.08
8.03
1.35
0.93
22.40
12.57
0.13
3.09
1.01
0.30
1.02
1.04
33.34
0.84
0.96
7.04
177.02
1.95
Number
of sites
1
7
11
8
7
7
8
7
2
1
8
1
8
7
2
9
11
4
4
for Trace Metals,
Annual Average
Concentration,
0.04
0.04
0.18
0.08
0.05
0.05
0.21
0.15
0.02
0.01
0.40
0.01
0.21
0.52
0.12
3.82
1.60
4.10
3.37
Ratio of average
concentrations
17.5
9.9
9.6
8.0
6.6
6.0
5.6
5.5
5.2
3.8
3.5
2.9
2.2
1.7
1.6
1.5
1.3
1.3
0.9
Based on 1 996 Ambient Measurements
Rural Sites
Number
of sites
65
4
65
65
65
2
8
18
8
2
8
7
18
2
65
11
2
2
8
2
4
2
2
17
4
2
9
39
17
Annual Average
Concentration,
0.22
0.52
0.34
1.66
1.26
1.22
1.46
4.53
7.30
1.23
3.40
0.05
5.05
0.87
0.71
19.12
11.35
0.12
3.05
1.00
0.30
1.02
1.13
41.65
1.10
1.70
33.86
861.31
13.33
Urban to Rural
Ratio of average
concentrations
5.2
3.2
3.1
2.8
2.7
2.6
2.5
2.3
1.9
1.8
1.8
1.6
1.6
1.6
1.3
1.2
1.1
1.0
1.0
1.0
1.0
1.0
0.9
0.8
0.8
0.6
0.2
0.2
0.1
CHAPTERS • AIR TOXICS 73
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Status of Urban and
Rural Ambient
Concentrations
Several hundred locations monitor
for air toxics year-round and have
sufficient data to estimate annual
average concentrations for many
HAPs. This section focuses on the
urban HAP list. Year-round ambient
concentrations are available for 25
HAPs on the list. Extensive data for
styrene and toluene are also avail-
able. Tables 5-2 and 5-3 compare
typical urban and rural annual aver-
age concentrations for VOCs, alde-
hydes and trace metals. Some of the
HAP data are represented by more
than one type of measurement [e.g.,
chromium (PM10) and chromium
(TSP)]. The amount of rural data is
limited for VOCs and for some of the
trace metal HAPs. Nevertheless,
tentative observations about urban-
rural differences in ambient levels
can be presented. In this chapter,
urban air quality is based on moni-
toring sites located within metropoli-
tan statistical areas. It is noted that
this definition is not necessarily the
same as the one which will be used in
Section 112k rule making.
For many VOCs and aldehydes,
the concentrations are relatively simi-
lar between urban and rural locations
(e.g., carbon tetrachloride, formalde-
hyde and benzene). In particular,
pollutants associated with ubiquitous
mobile sources appear to be more
similar between urban and rural
areas. On the other hand, several
HAPs show large differences among
sampling locations (e.g., styrene and
vinyl chloride). This contrast may be
attributed to many factors including
geographic distribution of emission
sources, the limited number of moni-
toring sites and the proximity of the
sites to those sources, the lifetime /
transport of the pollutant in the at-
mosphere and uncertainty in the
measurements. For some of the met-
als, average rural concentrations
appear higher (e.g., lead and cad-
mium). The number of monitoring
sites are limited, therefore these re-
ported rural concentrations are not
necessarily representative of typical
rural areas.
To further illustrate the variability
hi annual average HAP concentra-
tions, site-specific urban data are
separately examined for the distribu-
tion of annual average concentra-
tions. Figures 5-la - 5-lc present the
10*, srjth and 90* percentiles of an-
nual average concentrations for ur-
ban VOCs and aldehydes as well as
urban and rural trace metals. The
data are normalized to their respec-
tive urban or rural annual averages
to show the relative variability for
Figure 5-1 a. Relative variability in VOC and aldehyde annual average concentrations among urban sites, based on 1996 ambient
measurements.
>f National Avgcraga Concentration
5 so
n .
9
_
4
3
——3
i—
!
8
e
3 8
— i —
8 84
— i
9
5 3
r~ 24
1
1
8
8
1
6 1C
1
1
9
1 —
0 8
74
1
1
6 1
0
1;
i i
# No. of Sites
flnth %ile
•• 50th %ile
10th%ile
21 10
60
1 1 1 1
Note: "National Average" represents the average concentration of all included monitoring locations.
74 AIR TOXICS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 5-1 b. Relative variability in trace metal concentrations among urban sites, based on 1996 ambient measurements.
350
2/1 o«
13 • '
13
12
296
; 1 i —
71
•
•
8
° 35 90 4
0
25
88 20
•
17 '
o
I
•3 1
O
1
# No. of Sites
90th %iie -
• 50th %ile
10th%ile
13
3
2
— i —
7
1
— i —
o 13
3 13
— i —
31
T
I
— i — i — i-
13 13 13
i 1
300
o
1
250
o
O
o
200
I
150
o
1
I
o
2
100
50
Figure 5-1 c. Relative variability in trace metal concentrations among rural sites, based on 1996 ambient measurements.
900 T
800 --9
g 700
I
g 600
I
I" 500
•3 400
§
ra
1 300
t:
I 200
Q.
100
# No. of Sites
90th %ile
+ 50th %ile
10th%ile
17 65
39
18
11 65
65 18 8 8 2
2 65 2
65 2 4
2224272
o I T i 1-
^ /
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
each HAP. These figures reveal large
variations among reporting locations
for some VOCs and aldehydes (e.g.,
chloroform, formaldehyde and
trichloroethylene), and also show that
others (e.g., benzene and 1,3-butadi-
ene) are relatively similar among
monitoring locations. Again, annual
average concentrations for HAPs
associated with mobile sources tend
be more geographically homoge-
neous. For trace metals, reported
urban and non-urban concentrations
display large differences in annual
averages for some HAPs (e.g., total
suspended nickel and total sus-
pended lead among urban locations,
and arsenic among rural sites), while
they are relatively similar for others.
As stated above, the differences in
concentration variability among HAPs
may be attributed to many factors.
When examining differences in an-
nual means among individual moni-
toring locations, the quantity and
completeness of the monitoring data
may be important. Because air toxics
are typically sampled 30-100 days
per year, the lack of every day assess-
ments can contribute to imprecision
in annual average concentrations.
This is particularly true for sites with
large day-to-day variations in the
concentrations of certain HAPs.
These conclusions are tentative and
warrant further study.
Trends In Ambient Concentrations
The most widely measured HAP is
lead, which is also a criteria pollut-
ant. It is monitored in most states,
both in metropolitan and non-metro-
politan areas. Other urban HAPs
have been monitored in the metro-
politan areas of 24 states since the
mid 1990s. Several VOCs, aldehydes
and metals have good data history in
metropolitan areas. Most of these
monitors, however, are concentrated
in a few states, with 40 percent of
them in California alone. Neverthe-
less, these data can be used to pro-
vide a preliminary picture of
nationwide trends in urban air toxics.
Long-term monitoring in rural areas
for VOCs and aldehydes has general-
ly been more limited. A good history
of several trace metal concentrations
in rural areas is derived from the
Interagency Monitoring of Protected
Visual Environments (IMPROVE)
program. The locations for the urban
and rural monitors with long-term
data are shown in Figure 5-2.
Trends derived from these data are
separately presented for metropolitan
Figure 5-2. Locations for urban and rural air toxics monitors with long-term data.
Site Located in an MSA (167): •
Site Not Located in an MSA (75): O
Note: Sites only monitoring for lead (Pb) are not shown.
76 AIR TOXICS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table 5-4. National Summary of Ambient HAP Concentration Trends in Metropolitan Areas, 1993-1998
Hazardous Air
Pollutant
Acrylonitrile
Benzene
1 ,3-Butadiene
Carbon tetrachloride
Chloroform
1 ,2-Dibromoethane
1 ,2-Dichloropropane
Ethylene dichloride
Methylene chloride
1 ,1 ,2,2-Tetrachloroethane
Tetrachloroethylene
Trichloroethylene
Vinyl chloride
Arsenic (coarse)
Arsenic (fine)
Arsenic (PM10)
Arsenic (tsp)
Beryllium (PM10)
Beryllium (tsp)
Cadmium (PM10)
Cadmium (tsp)
Chromium (coarse)
Chromium (fine)
Chromium (PM10)
Chromium (tsp)
Chromium VI
Lead (coarse)
Lead (fine)
Lead (PM10)
Lead (tsp)
Manganese (coarse)
Manganese (fine)
Manganese (PM10)
Manganese (tsp)
Mercury (coarse)
Mercury (fine)
Mercury (PM10)
Mercury (tsp)
Nickel (coarse)
Nickel (fine)
Nickel (PM10)
Nickel (tsp)
Acetaldehyde
Formaldehyde
Acrolein
Benzo(a)pyrene
(total PM10 & vapor)
Dibenz(a,h)anthracene
(total PMio & vapor)
lndeno(1 ,2,3-cd)pyrene
(total PM10 & vapor)
Benzo(b)fluoranthene
(total PM,n & vapor)
Benzo(k)fluoranthene
(total PM10 & vapor)
Styrene
Toluene
Number of Urban Sites
Total
4
84
62
65
74
38
27
55
73
12
74
59
50
10
10
14
70
7
28
8
52
10 ,
10
14
63
26
10
10
28
266
10
10
13
54
10
10
6
26
10
10
13
63
10
16
7
18
18
18
18
18
60
78
Significant*
UP Trend
3
6
1
9
4
2
5
1
1
4
1
9
i
1
2
1
2
1
Non-Significant
UP Trend
2
6
17
25
28
5
5
11
13
6
13
19
10
1
1
8
6
3
9
2
7
21
1
2
47
4
3
12
3
2
4
19
2
3
13
6
12
4
1
5
1
14
9
No Trend
1
3
3
3
16
5
17
2
2
3
22
9
3
1
37
7
20
2
7
1
2
14
6
2
5
8
2
1
1
2
1
Non-Significant
DOWN Trend
1
48
16
23
23
15
9
16
37
4
43
24
13
1
6
7
17
2
1
31
5
6
6
30
19
4
7
10
147
6
5
8
31
2
2
4
6
4
6
27
3
2
1
16
13
16
15
17
35
42
Significant*
DOWN Trend
27
20
13
11
2
8
11
17
16
8
5
5
7
2
4
5
1
1
6
6
6
3
1
57
4
1
2
8
1
4
3
3
20
1
1
2
2
1
9
26
*Statistically significant at the 10-percent level (See Appendix B: Methodology, Air Toxics Methodology section).
CHAPTERS • AIR TOXICS 77
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
(urban) and non-metropolitan (rural)
sites. Table 5-4 present a national
summary of these 6-year trends in
ambient air toxics concentrations in
metropolitan statistical areas.
Among the 33 HAPs on the urban
strategy list, 25 pollutants have suffi-
cient historical data for this 6-year
trends assessment. These air con-
taminants include 13 of the 15 urban
VOCs, all eight urban HAP trace
metals, the three aldehydes and sev-
eral specific polycyclic aromatic hy-
drocarbons (PAHs). Also included
are styrene and toluene, which are
two additional pervasive air toxics
whose monitoring sites have good
nationwide coverage. The table pre-
sents the number of sites with in-
creases and decreases in measured
ambient concentrations from 1993-
1998. For trace metals, results repre-
senting more than one particulate
size fraction are included. Similarly,
trends are shown separately for sev-
eral individual PAHs which are con-
stituents of POM. For each of these
hazardous air pollutants with suffi-
cient historical data, the number of
sites with statistically significant
changes are highlighted in bold.
When many individual locations
reveal a significant change, this is
more characteristic of a national
trend.
Although these ambient air toxics
data are only available for a limited
number of metropolitan areas, the
results generally reveal downward
trends for most monitored HAPs on
the urban air toxics strategy list. The
most consistent improvements are
apparent for benzene which is pre-
dominantly emitted by mobile
sources; and for total suspended
lead. From 1993-1998, annual aver-
age concentrations for these two
HAPs declined 37 and 41 percent
respectively. The majority of ambient
concentrations of lead once came
from the tail pipe of cars. Since the -
mid-90s, however, lead has been
largely removed from gasoline and
almost all of these trace elements
now typically emanate from major
point sources. More information
about particulate lead can be found
in the criteria pollutant section in
Chapter 2 of this report. Ambient
concentrations of toluene (emitted
primarily from mobile sources) also
show a consistent decrease over most
reporting locations. Similar to ben-
zene, annual average toluene concen-
trations dropped 44 percent. The
reduction in benzene and toluene is
Figure 5-3a. National trend in annual/average benzene concentrations in metropolitan areas, 1993-1998.
7.0-
6.5
6.0-I
5.5
5.0-j
4.5
4.0
3.5
3.0-
2.5-
2.0
1.5-I
1.0
0.5-j
0.0
1
a
1
Q
-a
§
Sites Included in
National Trend
• Sufficient data (84)
« Insufficient data (595)
1993
1994
1995
1996
1997
1998
Year
78 AIR TOXICS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 5-3b. National trend in annual/average 1,3-butadiene concentrations in metropolitan areas, 1993-1998.
3.0
2.5
.2 2.0]
u
o 1.5-
U
1
0.5:
0.0-
Sites Included in
National Trend
• Sufficient data (62)
• Insufficient data (182)
1993
1994
1997
1998
1995 1996
Year
Figure 5-3c. National trend in annual/average total suspended lead concentrations in metropolitan areas, 1993-1998.
2.0
CO
!
a
o
1.5-
8 ^
CD
|
1 °-5:
o.o
Sites Included in
National Trend
• Sufficient data (265)
• Insufficient data (200)
1993
1994
1995
1996
1997
1998
Year
CHAPTERS • AIR TOXICS 79
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 5-3d. National trend in annual/average styrene concentrations in metropolitan areas, 1993-1998.
6.0
5.5
g" 5.0
5 4.51
"3 \
•5 4.01
a 3.5^
Sites Included in
National Trend
> Sufficient data (60)
» Insufficient data (458)
8
&
1
3.0
2-0 j
"j
1.0^
0.5 j
1
0.01
1993
1994
1997
1998
1995 1996
Year
Figure 5-3e. National trend in annual/average tetrachloroethylene concentrations in metropolitan areas, 1993-1998.
I
20-
15-
10-
2
I
1
Sites Included in
National Trend
> Sufficient data (74)
> Insufficient data (287)
1993
1994
1995
1996
1997
1998
Year
80 AIR TOXICS • CHAPTER 5
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 5-3f. National trend in annual/average toluene concentrations in metropolitan areas, 1993-1998.
30:
15:
I 20
I
I
U
03
*?
I 10
<
1
J] 5:
0:
Sites Included in
National Trend
• Sufficient data (78)
• Insufficient data (572)
1993
1994
1995
1996
1997
1998
Year
attributed to the use of reformulated
gas in many areas of the country.
Other HAPs (including styrene) also
reveal air quality improvement, but
the downward trends are not signifi-
cant across large numbers of moni-
toring locations. Some HAPs like
1,3-butadiene and tetrachloroethyl-
ene have trends that are more varied
across the nation and result in a rela-
tively flat national composite trend.
The composite urban trends for six
HAPs are graphically presented.
Boxplots of the annual average con-
centrations are shown for benzene,
1,3-butadiene, lead, styrene, tetra-
chloroethylene, and toluene in Fig-
ures 5-3a-f. The number and location
of the monitoring sites are also dis-
played. For comparison, the maps
also show the number of sites that
produced any measurement data
during the 6-year period. These fig-
ures depict the concentration distri-
butions among annual averages in
metropolitan areas from 1993-1998.
The average trend line for benzene,
lead, and toluene shows a steady
6-year air quality improvement, re-
flecting the consistent behavior
among most monitoring locations.
This represents a national pattern.
Average concentrations decreased 39,
40 and 44 percent respectively.
For other HAPs, most urban loca-
tions do not reveal predominant or
consistent trends among all monitor-
ing areas. In addition, most observed
trends for these 21 HAPs are not
statistically significant. This is attrib-
uted in part to few states with long-
term HAP monitoring, to the large
year-to-year variability in computed
annual average concentrations for
some HAPs and the large variety of
contributing emission sources for
many of the air toxics. For these pol-
lutants, a national composite trend
may not be meaningful at this time.
Although the general direction of
change is down for most HAPs on
the urban list, several states reveal
significant 6-year increases at a few
locations. These HAPs include
1,3-butadiene, carbon tetrachloride,
chloroform, ethylene dichloride,
methylene chloride, tetrachloroethyl-
ene (also known as perchloroethylene
or "perc") and trichloroethylene.
Except for 1,3-butadiene, all of the
above mentioned HAPs are generally
associated with major stationary
sources or a combination of major
and area sources. The majority of
emissions of 1,3-butadiene come
from mobile sources with the remain-
CHAPTER5 • AIR TOXICS 81
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 5-4a. Trend in annual average benzene concentrations for metropolitan sites in California, 1989-1998.
20-
CO
i
3. 15
a
£
a
10J
5-
I
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure 5-4b. Trend in annual average 1,3-butadiene concentrations for metropolitan sites in California, 1989-1998.
2.0
"a
2, 1.5
I
fi
d
o 1.0
g
0.5
0.0
I
1989 1990 1991 1992
1993 1994
Year
1995 1996 1997 1998
82 AIR TOXICS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 5-4c. Trend in annual average lead concentrations for metropolitan sites in California, 1989-1998.
0.10-
0.05-
I
0.00-
I
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
Figure 5-4d. Trend in annual average styrene concentrations for metropolitan sites in California, 1989-1998.
3.0-
2.5-
I ^
ti
o 1.5-
U
1.0:
0.5:
0.0
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Year
CHAPTERS • AIR TOXICS 83
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 5-4e. Trend in annual average tetrachloroethylene concentrations for metropolitan sites in California, 1989-1998.
8.0 j
7.5-
,-, 7.0-
CO
J 6.5-
ob
A 6.0-
g 5.5 •
1 «'
d , _
8 4.0 •
a 3<5'
a 3.0-
a
2 15-
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
der mostly from area sources. To
illustrate a few of the HAPs without
consistent trends among reporting
stations, boxplots for 1993-1998 are
presented for 1,3-butadiene, styrene
and tetrachloroethylene. The na-
tional trends for these HAPs appear
to be flat for the six years, except for
average concentration of styrene
which shows a drop in 1998. To illus-
trate the behavior of these com-
pounds in a particular region of the
country, trends of monitoring sites in
California are presented on the fol-
lowing page.
The State of California has the
largest and longest running air toxics
monitoring network. They have over
30 sites with a 10-year history for
several VOCs and almost as many for
several trace metals. These data allow
us to take a look at a longer rime trend
in air toxics. Among the HAPs dis-
cussed in this section, notable im-
provements are seen for benzene,
1,3-butadiene, tetrachloroethylene
and toluene. The impressive air qual-
ity improvement for urban benzene
in California is shown in Figure 5-4a.
This figure illustrates the large de-
crease in ambient concentrations
which occurred during the early
1990s. Annual average concentrations
declined 70 percent over the 10-year
period. Ambient concentrations of
tetrachloroethylene associated with
dry cleaners is down 58 percent (Fig-
ure 5-4e). Toluene associated with
mobile sources also showed consis-
tent declines which averaged 44 per-
cent across the state (Figure 5-4f).
Another HAP which predominantly
comes from mobile sources is 1,3-
butadiene. Although site-specific
trends for this pollutant were mixed,
the composite trend in Figure 5-4d
shows an overall 35-percent decline
in ambient concentrations. The reduc-
tions in ambient concentrations of
tetrachloroethylene are due to better
controls on the use of solvents, while
the improvements in benzene, 1,3-
butadiene and toluene is attributed to
the reformulation of gasoline. (For
more information about trends in
these emissions, see the ozone section
in Chapter 2.) For additional detail
on the derivation of Figures 5-3a to
5-4f, see Appendix B: Methodology.
Results from California's total
suspended particulate lead network
are consistent with the national
trends. Annual average concentra-
tions declined 63 percent and 27
percent over the 10-year and 6-year
periods respectively. California has
Figure 5-5. Trends in Annual Average Fine Particle Chromium Concentrations in Rural Areas, 1993-1998.
0.0020-
0.0015 -
CD
a
5 0.0010
u
CD
I
'a 0.0005
o.oooo-
Sites Not Located
in an MSA
• Sufficient data (57)
® Insufficient data (30)
1993 1994 1995 1996 1997 1998
Year
CHAPTERS • AIR TOXICS 85
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table 5-5. National Summary of Ambient HAP Concentration Trends in Rural Areas, 1993-1998
Hazardous Air
Pollutant
Benzene
1.3-Butadiene
Carbon tetrachloride
Chloroform
1 ,2-Dichloropropane
Ethylene dichloride
Methvlene chloride
Tetrachloroethylene
Trichloroethylene
Vinyl chloride
Arsenic (coarse)
Arsenic (fine)
Arsenic (PM10)
Arsenic (tsp)
Beryllium (PM10)
Beryllium (tsp)
Cadmium (PM10)
Cadmium (tsp)
Chromium (coarse)
Chromium (fine)
Chromium (PM10)
Chromium (tsp)
Chromium VI
Lead (coarse)
Lead (fine)
Lead (PM10)
Lead (tsp)
Manganese (coarse)
Manganese (fine)
Manganese (PM10)
Manqanese (tsp)
Mercury (coarse)
Mercury (fine)
Mercury (PM,0)
Mercury (tsp)
Nickel (coarse)
Nickel (fine)
Nickel (PM10)
Nickel (tsp)
Acetaldehyde
Formaldehyde
Acrolein
Styrene
Toluene
Number of Rural Sites
Total
5
4
3
4
4
4
4
4
4
4
2
61
6
5
2
3
2
6
2
61
6
7
1
2
61
8
31
2
61
6
6
2
2
4
1
2
61
6
7
1
1
1
5
5
Significant*
UP Trend
3
28
1
1
1
1
1
Non-Significant
UP Trend
2
3
1
40
1
1
1
1
29
2
2
45
1
5
1
25
3
1
2
1
1
12
1
1
2
3
No Trend
1
1
1
1
1
1
3
3
1
1
1
2
1
1
1
1
1
1
1
Non-Significant
DOWN Trend
4
1
1
3
3
3
4
2
3
1
17
3
1
2
1
1
3
3
2
1
15
3
15
1
35
2
5
1
1
1
39
3
4
1
1
1
3
2
Significant*
DOWN Trend
1
3
1
1
2
1
1
2
2
1
1
1
11
1
1
8
1
1
"Statistically significant at the 10-percent level (See Appendix B: Methodology, Air Toxics Methodology section).
86 AIR TOXICS • CHAPTER 5
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
also been measuring fine particle
lead (from PM2.5) and coarse particle
lead (from PM10_2.5) in its urban ar-
eas. Although concentrations are a
small fraction of the total suspended
lead, these data also show 6-year
declines of 26 and 54 percent, respec-
tively. California's trace metal data
also shows declines in total sus-
pended chromium (-29 percent) and
the particularly hazardous
hexavalent chromium (-52 percent).
Ambient air toxics data in rural
areas are much more limited, but the
results in Table 5-5 and Table A-20
also indicate widespread air quality
improvement for many monitored
urban strategy HAPs. Significant
downward trends are noted among
the few rural sites for benzene and
several other VOCs. Lead concentra-
tions in rural areas are also down. In
contrast, a notable steady increase in
fine particle chromium concentra-
tions is observed in the rural data set.
This is illustrated in Figure 5-5. Al-
most all rural monitoring sites show
a 6-year increase in ambient chro-
mium concentrations and most of
them are statistically significant.
Average concentrations increased 88
percent. The reason for this increase
in rural chromium concentrations is
not known at this time. The result
also needs to be viewed with caution
because the reported concentrations
are close to the detection limits of the
monitoring method (0.57 ng/m3).8
Nevertheless, there is a strong trend
in the concentrations above this level.
Future trend reports will present
more detailed trends in chromium
and other HAP trace metals derived
from the IMPROVE network and
other rural monitoring locations.
Atmospheric Deposition
National Atmospheric Deposition
Program/National Trends
Network
The National Atmospheric Deposi-
tion Program (NADP) began in 1978
as a cooperative program between
federal and state agencies, universi-
ties, electrical utilities, and other
industries to determine geographical
patterns and trends in wet deposition
of sulfate, nitrate, hydrogen ion, am-
monium, chloride, calcium, magne-
sium, and potassium. The NADP
was renamed as NADP/NTN (Na-
tional Trends Network) in the mid-
1980s when the program had grown
to almost 200 monitoring sites. The
monitoring sites are located in rural
areas, and data are collected on a
weekly basis. The collected data pro-
vide insight into natural background
levels of pollutants. The network of
NADP/NTN monitoring sites allows
for the development of concentration
and wet deposition maps to describe
the trends and spatial patterns in the
constituents of acid precipitation.
The Mercury Deposition Network
(MDN), which is another component
of the NADP, measures mercury
levels in wet deposition at over 40
NADP sites located in 16 states and
two Canadian provinces.
Mercury's adverse effects on eco-
logical and public health have raised
the level of awareness regarding its
persistence in the environment. As a
result, there has been a concerted
effort by local, state, and national
environmental agencies to accurately
measure the annual progress of regu-
lations and technologies aimed at
reducing mercury. The MDN is a key
element of these efforts by monitor-
ing the presence of mercury and
methyl mercury in precipitation.
This has enabled scientists to compile
a national database of weekly pre-
cipitation concentrations. As a result,
state and federal air regulators can
monitor progress in reducing mercury
concentrations and amend policy deci-
sions accordingly. There are plans to
expand the network in the near future,
pending availability of new funds.
Additional information about the
network is available on the Internet
at http://nadp.sws.uiuc.edu/mdn/.
Data from 1996 and 1997 indicate
that the volume-weighted mean con-
centration of total mercury in precipi-
tation from 22 sites ranged from
6.0-18.9 ng/L and annual deposition
of mercury ranged from 2.1-25.3
ug/m2. In 1997, average mercury
concentrations in rain ranged from
6.2-18.3 ng/L at the 21 sites that had
a full year of monitoring data and the
average concentration for all sites
was 10.6 ng/L. In 1996, average
mercury concentrations at nine sites
with a full year of data ranged from
6.0-14.1 ng/L with an average for all
sites of 10.2 ng/L. In 1997, the an-
nual average wet deposition of mer-
cury for 21 sites ranged from 4.3-25.3
ug/m2, whereas in 1996, the annual
average wet deposition of mercury
for nine sites ranged from 6.3-19.7
ug/m2. In the eastern United States,
average summer mercury concentra-
tions are more than double winter
concentrations and average summer
deposition values are more than three
times winter values. This, can be
explained by higher concentrations of
mercury in the rain and higher rain-
fall amounts during the summer.?
Integrated Atmospheric
Deposition Network
The Integrated Atmospheric Deposi-
tion Network (IADN) is a joint Unit-
ed States-Canada program begun in
CHAPTER 5
AIR TOXICS
87
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
1990 under a formal 6-year imple-
mentation.™ The IADN collects data
that can be useful in assessing the
relative importance of atmospheric
deposition. IADN measures concen-
trations of target chemicals in rain
and snow (wet deposition), airborne
particles (dry deposition), and air-
borne organic vapors.11 Under
IADN, trends in pollutant concentra-
tions in air and precipitation are as-
sessed and loading estimates of
atmospheric deposition and volatil-
ization of pollutants are made every
two years. The IADN network cur-
rently consists of one master station
per Great Lake and 14 satellite sta-
tions. Stations are located in remote
areas and do not assess urban sourc-
es of pollution.
General conclusions based on
IADN data include the following:
• Levels in air and precipitation ap-
pear stable for current-use pesti-
cides such as endosulphan, but
levels for most other pesticides,
PCBs, and lead are decreasing.
• Gas absorption appears to be the
dominant deposition process for
delivering SVOCs, including PCBs
and PAHs, to lake surfaces, while
wet and dry deposition dominate
for the trace elements and higher
molecular weight PAHs.
• For some IADN substances, like
dieldrin and PCBs, the surface wa-
ters are behaving like a source since
the amount that is volatilizing from
the water is greater than the amount
being deposited to the water.
• The lakes are sensitive to the at-
mospheric concentration of IADN
chemicals, and this highlights the
fragility of these resources given
that long-range transport from
other regions may be a significant
source of toxic pollutants.
• Air trajectory analyses indicate
that many SVOCs are potentially
originating from outside the Great
Lakes basin, whereas trace metals'
and PAHs may be associated with
local sources.12
In 1998, the Second Implementa-
tion Plan for 1998-2004 was devel-
oped based on a review of the
program from 1990-1996. No major
changes are anticipated under the
Second Implementation Plan. The
IADN will continue surveillance and
monitoring activities, related re-
search, and to provide information
for intergovernmental commitments
and agreements. Additional work to
be completed under the Second
Implementation Plan is the develop-
ment of a database for all U.S. and
Canadian data. Potential modifica-
tions will be discussed in relation to
the placement of satellite stations to
assess urban inputs and air-water gas
exchange, criteria for changes to the
IADN chemical list, coordination
with other research activities, quality
assurance and control of IADN op-
erations, and communication of
IADN results.1*
88 AIR TOXICS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
References
1. This list originally included 189
chemicals. The CAA allows EPA to
modify this list if new scientific infor-
mation becomes available that indi-
cates a change should be made. Using
this authority, the Agency modified the
list to remove caprolactam in 1996,
reducing the list to 188 pollutants
(Hazardous Air Pollutant List; Modifica-
tion, 61 FR 30816, June 18,1996).
2. "Update: National Listing of Fish
and Wildlife Advisories/' announcing
the availability of the 1998 update for
the database: National Listing of Fish
and Wildlife Advisories (NLFWA);
U.S. EPA Fact Sheet, EPA-823-F-99-005,
July 1999. Available on the Internet at:
http://wwrw.epa.gov/ost/fish.
3. Hillery, B.R., Hoff, R.M., and Hites,
R.A. 1997. "Atmospheric contaminant
deposition to the Great Lakes deter-
mined from the Integrated Atmospher-
ic Deposition Network." Chapter 15 in
Atmospheric Deposition of Contaminants
to the Great Lakes and Coastal Waters.
1997, Joel E. Baker, Editor. SETAC
Press. (Society of Environmental Toxi-
cology and Chemistry.)
4. Evers, D. 1998. Assessing availabil-
ity and risk of methylmercury to the
common loon in New Hampshire and
Vermont. A preliminary report. Sub-
mitted to U.S. EPA, Office of Air Quali-
ty Planning and Standards, December
3, 1998.
5. "National Air Toxics Program: The
Integrated Urban Strategy," Federal
Register, 64 FR 38705, Washington,
D.C., July 19,1999. Available on the
Internet at: http://www.epa.gov/ttnu-
atwl/urbanpg.html.
6. "Air Toxics Monitoring Concept
Paper," U.S Environmental Protection
Agency, Office of Air Quality Planning
and Standards, Research Triangle Park,
NC. February 29, 2000. Peer Review
Draft. Available on the Internet at:
http://www.epa.gov/ttn/amtic/
airtxfil.html.
7. "1997 Urban Air Toxics Monitoring
Program (UTAMP)," EPA-454/R-99-
036. January 1999. Available on the
Internet at http://www.epa.gov/ttn/
amtic/airtxfil.html.
8. Visibility Monitoring Guidance
1999, U.S. Environmental Protection
Agency, Office of Air Quality Planning
and Standards, Research Triangle Park,
NC 27711, June 1999, EPA-454/R-99-
003.
9. Sweet, C.W., E. Prestbo, B. Bru-
nette. 1999. Atmospheric wet deposi-
tion of mercury in North America.
Proceedings of the 92nd Annual Meet-
ing of the Air and Waste Management
Association. June 21-23,1999, St. Lou-
is, MO.
10. The IADN fulfills legislative man-
dates in Canada and the United States
that address the monitoring of air
toxics. An international Great Lakes
deposition network is mandated by
Annex 15 of the Great Lakes Water
Quality Agreement between the United
States and Canada. In the United
States, the CAA requires a Great Lakes
deposition network.
11. The target chemicals include PCBs,
pesticides, PAHs and metals. The
compounds included as "target chemi-
cals" were selected based on the fol-
lowing criteria: presence on List 1 of
Annex 1 of the Great Lakes Water
Quality Agreement (substances be-
lieved to be toxic and present in the
Great Lakes); established or perceived
water quality problem; presence on the
International Joint Commission's Wa-
ter Quality Board's list of criteria pol-
lutants; evidence of presence in the
atmosphere and an important deposi-
tion pathway; and feasibility of mea-
surement in a routine monitoring net-
work.
12. U.S./Canada IADN Scientific Steer-
ing Committee. 1998. Technical sum-
mary of progress under the integrated
atmospheric depositions program
1990-1996.
CHAPTER 5
AIR TOXICS
89
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
90 AIR TOXICS • CHAPTERS
-------
CHAPTER 6
Visibility Trends
http://www.epa.gov/oar/aqtrnd98/chapter6.pdf
Introduction
The Clean Air Act (CAA) authorizes
the United States Environmental
Protection Agency (EPA) to protect
visibility, or visual air quality,
through a number of programs.
These programs include the National
Visibility Program under sections
169a and 169b of the Act, the Preven-
tion Of Significant Deterioration
Program for the review of potential
impacts from new and modified
sources, the secondary National Am-
bient Air Quality Standards (NAAQS)
for PM10 and PM2.5, and section 401
under the provisions for acid deposi-
tion control. The National Visibility
Program established in 1980 requires
the protection of visibility in 156
mandatory federal Class I areas
across the country (primarily national
parks and wilderness areas). The
CAA established as a national visibil-
ity goal, "the prevention of any fu-
ture, and the remedying of any
existing, impairment of visibility in
mandatory federal Class I areas in
which impairment results from man-
made air pollution." The Act also calls
for state programs to make "reasonable
progress" toward the national goal.
In 1987, the Interagency Monitor-
ing of Protected Visual Environments
(IMPROVE) visibility network was
established as a cooperative effort
between EPA, the National Oceanic
and Atmospheric Administration, the
National Park Service, the U.S. Forest
Service, the Bureau of Land Manage-
ment, the U.S. Fish & Wildlife Ser-
vice, and state governments. The
objectives of the network are to estab-
lish current conditions, to track
progress toward the national visibil-
ity goal by documenting long-term
trends, and to provide information
for determining the types of pollut-
ants and sources primarily respon-
sible for visibility impairment.
Chemical analysis of aerosol mea-
surements provides ambient concen-
trations and associated light
extinction for PM10, PM2.5, sulfates,
nitrates, organic and elemental car-
bon, crustal material, and a number
of other elements. The IMPROVE
program has established protocols for
aerosol, optical, and photographic
monitoring methods, and these meth-
ods are employed at more than 70
sites, most of which are Class 1 areas.
In the calendar year 2000, an addi-
tional 80 monitoring sites using the
IMPROVE aerosol monitoring proto-
col will be established. The analyses
presented in this chapter are based
on data from the IMPROVE network,
which can be found on the Internet
at: ftp://alta_vista.cira.colostate.edu/
DATA/IMPROVE 1
This chapter presents aerosol and
light extinction data collected be-
tween 1989 and 1998 at 34 Class I
areas in the IMPROVE network. Be-
cause the CAA calls for the tracking
of "reasonable progress" in prevent-
ing future impairment and remedy-
ing existing impairment, this analysis
looks at trends in visibility impair-
ment across the entire range of the
visual air quality distribution. To
facilitate this approach, visibility data
have been sorted into quintiles, or 20
percent segments, of the overall dis-
tribution, and average values have
been calculated for each quintile.
Trends are presented in terms of the
haziest ("worst") 20 percent, typical
("middle") 20 percent, and clearest
("best") 20 percent of the annual
distribution of data. Figure 6-1 pro-
vides a photographic illustration of
very clear and very hazy conditions
at Glacier National Park in Montana,
and Dolly Sods Wilderness Area in
West Virginia.2 Figure 6-2 is a map of
the 34 Class I areas with seven or
more years of IMPROVE monitoring
data included in this analysis.
Nature and Sources of
the Problem
Visibility impairment occurs as a
result of the scattering and absorp-
tion of light by particles and gases in
the atmosphere. It is most simply
described as the haze that obscures
the clarity, color, texture, and form of
what we see. The same particles
CHAPTERS • VISIBILITY TRENDS 91
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 6-1. Images of Glacier National Park and Dolly Sods Wilderness Area.
Condition:
Bad
Visual Range:
15-25 km
Declvlews:
33-28
Condition:
Good
Visual Range:
150-200 km
Declvlews:
10-7
Condition:
Bad
Visual Range:
<10 km
Dec/views:
>37
Condition:
Good
Visual Range:
80-140 km
Deciviews:
16-10
Glacier National Park
Dolly Sods Wilderness Area
linked to serious health and environ-
mental effects (sulfates, nitrates, or-
ganic carbon, elemental carbon
[commonly called soot], and crustal
material) can also significantly affect
our ability to see.
Both primary emissions and sec-
ondary formation of particles contrib-
ute to visibility impairment. Primary
particles, such as elemental carbon
from diesel and wood combustion or
dust from certain industrial activities
or natural sources, are emitted di-
rectly into the atmosphere. Second-
ary particles that are formed in the
atmosphere from primary gaseous
emissions include sulfate from sulfur
dioxide (SO2) emissions, nitrates
from nitrogen oxide (NOX) emissions,
and organic carbon particles formed
from condensed hydrocarbon emis-
sions. In the eastern United States,
reduced visibility is mainly attribut-
able to secondarily formed particles,
particularly those less than a few
micrometers in diameter. While sec-
ondarily formed particles still ac-
count for a significant amount in the
West, primary emissions from sources
such as woodsmoke generally con-
tribute a larger percentage of the total
particulate load than in the East. The
only primary gaseous pollutant that
directly reduces visibility is nitrogen
dioxide (NO2), which can sometimes
be seen in a visible plume from an
industrial facility, or in some urban
areas with high levels of motor ve-
hicle emissions.
Visibility conditions in Class I and
other rural areas vary regionally
across the United States. Rural areas
in the East generally have higher
levels of impairment than most re-
mote sites in the West. Higher east-
ern levels are generally due to higher
regional concentrations of sulfur
dioxide and other anthropogenic
emissions, higher estimated regional
background levels of fine particles,
and higher average relative humidity
levels. Humidity can significantly
increase the effect of pollution on
visibility. Some particles, such as
sulfates, accumulate water and grow
in size, becoming more efficient at
scattering light. Annual average
relative humidity levels are 70-80
percent in the East as compared to
50-60 percent in the West. Poor sum-
mer visibility in the eastern United
States is primarily the result of high
sulfate particle concentrations com-
bined with high humidity levels.
Visibility conditions are commonly
expressed in terms of three math-
ematically related metrics: visual
range, light extinction, and deci-
views. Visual range is the metric best
92 VISIBILITY TRENDS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 6-2. IMPROVE sites meeting data completeness requirements.
IMPROVE Sites
n Complete for Trends Only
x Complete for 1998 Only
m Complete for Both
Note: The Washington, DC site is not included in the rural visibility trends analysis.
known by the general public. It is the
maximum distance at which one can
identify a black object against the
horizon, and is typically described in
miles or kilometers. Light extinction,
inversely related to visual range, is
the sum of light scattering and light
absorption by particles and gases in
the atmosphere. It is typically ex-
pressed in terms of inverse mega-
meters (Mm.-1), with larger values
representing poorer visibility. Unlike
visual range, the light extinction
coefficient allows one to express the
relative contribution of one particu-
late matter (PM) constituent versus
another to overall visibility impair-
ment. Using speciated mass measure-
ments collected from the IMPROVE
samplers "reconstructed light extinc-
tion" can be calculated by multiplying
the aerosol mass for each constituent
by its appropriate "dry extinction
coefficient," and then summing these
values for each constituent. Because
sulfates and nitrates become more
efficient at scattering light with in-
creasing humidity, these values are
also multiplied by a relative humid-
ity adjustment factor.3 Annual and
seasonal light extinction values de-
veloped by this approach correlate
well with optical measurements of
light extinction (by transmissometer)
and light scattering (by nephelometer).
The deciview metric was devel-
oped because changes in visual range
and light extinction are not propor-
tional to human perception of visibility
impairment. For example, a 5-mile
change in visual range can be either
very apparent or not perceptible,
depending on the base line level of
ambient pollution. The deciview
metric provides a linear scale for
perceived visual changes over the
entire range of conditions, from clear
to hazy, analogous to the decibel
scale for sound. Under many scenic
conditions, a change of one deciview
is considered to be perceptible by the
average person. A deciview of zero
represents pristine conditions.
It is important to understand that
the same amount of pollution can
have dramatically different effects on
visibility depending on existing con-
ditions. • Most importantly, visibility
in cleaner environments is more sen-
sitive to increases in PM2.s particle
concentrations than visibility in more
polluted areas. This principle is illus-
trated in Figure 6-3, which character-
izes visibility at Shenandoah
National Park under a range of con-
ditions.5 A clear day at Shenandoah
can be represented by a visual range
of 80 miles, with conditions approxi-
mating naturally-occurring visibility
(i.e., without pollution created by
human activities). An average day at
Shenandoah is represented by a vi-
sual range of 18 miles, and is the
result of an additional 10 mg/m3 of
fine particles in the atmosphere. The
two bottom scenes, with visual
ranges of eight and six miles respec-
tively, illustrate that the perceived
change in visibility due to an addi-
tional 10 mg/m3 of fine particles to
an already degraded atmosphere is
much less perceptible than adding
this amount to a clean atmosphere.
Thus, to achieve a given level of per-
ceived visibility improvement, a
large reduction in fine particle con-
centrations is needed in more pol-
luted areas. Conversely, a small
amount of pollution in a clean area
can dramatically decrease visibility.
CHAPTERS • VISIBILITY TRENDS 93
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Long-Term Trends
(1970-1990)
Visibility impairment is presented
here using visual range data collected
since 1960 at 280 monitoring stations
located at airports across the country.
Trends in visibility impairment can
be inferred from these long-term
records of visual range. Figure 6-4
describes long-term U.S. visibility
impairment trends derived from such
data.4 The maps show the amount of
haze during the summer months of
1970,1980, and 1990. The dark blue
color represents the best visibility,
and red represents the worst visibili-
ty. Overall, these maps show that
summer visibility in the eastern Unit-
ed States declined between 1970 and
1980, and improved slightly between
1980 and 1990. These trends follow
overall trends in emissions of sulfur
oxides during these periods.
Recent Trends
(1989-1998)
Aerosol and light extinction data are
presented for 34 sites which pro-
duced at least seven years of fine
particle data from 1989-1998:10 are
located in the east, and 24 are located
in the west, as shown in Figure 6-2.
Because of the significant regional
variations in visibility conditions, this
chapter does not present aggregate
national trends, but instead groups
the data into eastern and western
regions. As noted earlier, trends in
this chapter are presented in terms of
the annual average values for the
clearest ("best") 20 percent, middle
("typical") 20 percent, and haziest
("worst") 20 percent of the days mon-
itored each year. To date, two
24-hour aerosol samples have been
taken each week from IMPROVE
Figure 6-3. Shenandoah National Park on clear and hazy days and the effect of
adding 10 pg/m3 of fine particles to each.
Clean Day + 10 yg/mS
standard Visual Range = 80 Miles standard Visual Range — 18 Miled
Dirty Day
Dirty Day -t I0ug/m3
HMMMMMMMHI
Standard Visual Range = 8 Miles standard Vlsuif Rarige = 6 Miles'
sites, resulting in a potential for 104
sampling days per year. Beginning
in 2000, aerosol samples will be taken
every three days, consistent with the
approach used for national PM2.5
aerosol monitoring.
Regional Visibility Trends for the
Eastern and Western United
States
Figures 6-5a and 6-5b illustrate east-
ern and western trends for total light
extinction. These figures, presented
with equivalent scales, demonstrate
the regional difference in overall
levels of visibility impairment. For
this graph, the light scattering associ-
ated with gaseous molecules in clear
air is included (known as Rayleigh
extinction). One can see that the
worst visibility days in the West are
only slightly more impaired than the
best days in the East. It should also
be noted that beginning in 1992, sev-
en additional eastern sites are reflect-
ed in Figure 6-5a, bringing the total
number of eastern sites reflected in
the values plotted in Figure 6-5a for
1992-1998, to 10. By adding the sev-
en eastern sites to the data set, the
magnitude of average impairment
levels has increased, although the
general slope of the trends for clear-
est, typical, and haziest days appear
similar to the trends based on three
sites. Figure 6-5a shows that in the
East, the haziest visibility days do
not appear to be getting any better.
Overall, essentially no change in
visibility is noted between 1989 and
1998 (based on 3 sites), and a 4-per-
cent degradation occurred since 1992
(based on 10 sites). It is noted that
impairment on the haziest days in the
East showed modest improvement in
1993. The best visibility days appear
to be improving for the three sites
over the 10-year period, but show no
change since 1992 based on the 10
locations. The typical days (or mid-
dle 20 percent of the distribution)
show more than a 10-percent visibili-
ty improvement for the three sites,
94 VISIBILITY TRENDS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 6-4. Long-term trend for 75th percentile light coefficient from airport visual data
(July-September).
1970
1980
1990
and a more modest 5-percent change
since 1992 for the 10 sites.
In the West, there appears to be
steady visibility improvement for the
clearest, typical, and haziest days as
presented in Figure 6-5b for the pe-
riod 1989-1998. Total light extinction
for the aggregation of 24 western
sites declined by 10-15 percent for
each of the 3 categories. This im-
provement in total light extinction for
the worst days corresponds to a re-
duction of 0.9 deciviews.
The Components of PM
Contributing to Trends in
Visibility Impairment
The area plots in Figures 6-6a
through 6-6f show the relative contri-
bution to aerosol light extinction by
the five principal particulate matter
constituents measured by IMPROVE
at eastern and western sites for the
best, middle, and worst 20 percent
days. Note that the scale differs for
the eastern and western figures in
order to more clearly present the
relative contribution of the five com-
ponents. By understanding the total
magnitude of each PM2.5 component,
the change in aerosol composition
over time, and the effect of these
components on changing visibility,
policymakers can design strategies to
address health and environmental
concerns.
In the East, (Figures 6-6a, b, and c),
sulfate is clearly the largest contribu-
tor to visibility impairment, ranging
from an average of 75-79 percent of
each year's annual aerosol extinction
during the haziest days to 62-69
percent on the typical days, and to
53-62 percent on the dearest days.
Over the 1992-1998 period, the mag-
nitude of aerosol extinction due to
sulfates increased, most notably be-
tween 1997 and 1998. This change
CHAPTERS • VISIBILITY TRENDS 95
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
corresponds to the reported increase
in sulfate aerosols and summer time
increase in regional SO2 emissions
discussed in Chapter 7 (Atmospheric
Deposition of Sulfur and Nitrogen
Compounds). The organic carbon is
the next largest contributor to visibil-
ity impairment in the East, account-
ing for 11-15 percent of annual
aerosol extinction on the best days
and 10-11 percent on the most un-
paired days. The third largest con-
tributor in the East is nitrate, which
also accounts for about 10-16 percent
of annual aerosol light extinction on
the best days and about 2-6 percent
on the haziest days.
In the West, sulfate is also the
most significant single contributor to
aerosol light extinction on the
clearest, typical, and haziest days.
Sulfate accounts for 30-40 percent of
annual aerosol light extinction on the
best days, 36-44 on the typical days,
and 34-41 on the haziest days. How-
ever, organic carbon (20-33 percent),
crustal material (16-25 percent), and
nitrates (7-12 percent) play a more
significant role (as a percentage of
aerosol extinction) in western sites
than eastern ones. Based on this
aggregation of 24 sites, the decrease
in light extinction noted above can be
attributed to downward trends in
aerosol elemental carbon and organic
carbon. However, carbon increased
between 1997 and 1998, offsetting
some of these improvements in west-
ern Class I areas.
Trends in Specific Class I Areas
IMPROVE data from 34 Class I area
monitoring sites7 were analyzed for
upward or downward trends using a
nonparametric regression methodolo-
gy described in Appendix B: Method-
ology.
Figure 6-5a. Total light extinction trends for eastern Class I areas for clearest, middle,
and haziest 20 percent of the days in the distribution, 1989-1998.
Light Extinction, Mm-1
200
150
100
50
Haziest 20 percent
3 Sites having data for all ten years
10 Sites—original 3 plus 7 additional
sites having data from 1992 to 1998
Middle 20 percent
Clearest 20 percent
89 90 91 92 93 94 . 95 96 97 98
Figure 6-5b. Total light extinction trends for western Class I areas for clearest, middle,
and haziest 20 percent of the days in the distribution, 1989-1998.
Light Extinction, Mm-1
200
150
100
50
24 Sites
Haziest 20 percent
—_-
Middle 20 percent
Clearest 20 percent
89 90 91 92 93 94 95
97 98
Note: In the eastern Class I area plots, the 1989-1991 trend is based on the three
sites with available data. Beginning in 1992 and going through 1998, there are seven
additional sites with trend data.
96 VISIBILITY TRENDS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Aerosol Light Extinction, Mra-1
200
150
100
50
3 Sites
10 Sites
0
89 90 91 92 93 94 95 96 97
Aerosol Light Extinction, Mm-1
200
150
100
50
3 Sites
10 Sites
89 90 91 92 93 94 95 96 97
Aerosol Light Extinction, Mm-1
200
150
100
50
3 Sites
10 Sites
Figure 6-6a. Aerosol light
extinction in eastern Class I
areas for the clearest 20
percent of the days in the
distribution, 1989-1998.
D Organic Carbon
g Nitrate
D Sulfate
• Elemental Carbon
H Crustal Material
Figure 6-6b. Aerosol light
extinction in eastern Class I
areas for the middle 20
percent of the days in the
distribution, 1989-1998.
Figure 6-6c. Aerosol light
extinction in eastern Class I
areas for the haziest 20
percent of the days in the
distribution, 1989-1998.
Table 6-1 summarizes the trends
analysis performed on these 34 sites
for total light extinction (expressed in
deciviews) on an area-by-area basis.
Four areas in the West showed a signifi-
cant downward trend in deciviews on
the haziest days. However, the 30 re-
maining Class I areas did not have
significant visibility improvement on
the haziest days over the 7- to 10-year
period.
Current Visibility
Conditions
Current annual average conditions
range from about 18-^10 miles in the
rural East and about 35-90 miles in
the rural West. On an annual average
basis, natural visibility conditions
have been estimated at approximate-
ly 80-90 miles in the East and up to
140 miles in the West.4 Natural visi-
bility varies by region, primarily
because of slightly higher estimated
background levels of PM2.5 particles in
the East, and the more significant effect
of relative humidity on particle concen-
trations in the East than in the West.
Figures 6-7a, 6-7b, and 6-7c illus-
trate regional visibility impairment in
terms of reconstructed aerosol light
extinction based on measurements at
IMPROVE sites between 1995 and
1997. Maps are presented for the
clearest, typical, and haziest 20 per-
cent of the distribution. The pie
89
90
91 92
93
94 95
96
97
98
Notes:
1) To better discern the trend in each
component, the vertical scales for the
plots of the western Class I areas are
smaller than those for the plots of the
eastern Class I areas.
2) In the eastern Class I area plots, the
1989-1991 trend is based on the 3 sites
with available data. Beginning in 1992
and going through 1998, there are 7
additional sites with trend data.
CHAPTERS • VISIBILITY TRENDS 97
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
charts show the relative contribution
of different particle constituents to
visibility impairment. Annual aver-
age aerosol light extinction due to
these particles is indicated by the
value next to each pie and by the size
of each pie.6 Figure 6-7 also shows
that visibility impairment is generally
greater in the rural East compared to
most of the West. As noted earlier,
the pies show that, for most rural
eastern sites, sulfates account for
more than 60 percent of annual aver-
age light extinction on the best days
and for more than 75 percent of an-
nual average light extinction on the
haziest days. Sulfate plays a particu-
larly significant role in the humid
summer months due to its nature to
attract and dissolve in atmospheric
water %'apor, most notably in the
Appalachian, northeast, and
mid-south regions. The figure also
shows that organic carbon and ni-
trates each account for 10-15 percent
of aerosol extinction on the dearest
days while elemental carbon only
contributes 5-7 percent. On the other
hand, organic carbon contributes
around 10 percent to aerosol light
extinction on the haziest days while
nitrates and elemental carbon each
typically contribute 2-6 percent.
In the rural West, sulfates also
play a significant role, typically ac-
counting for about 30-40 percent of
aerosol light extinction on the best
days and 35-45 percent on the hazi-
est days. In several areas of the West,
however, sulfates account for over 50
percent of annual average aerosol
extinction, including Mt Rainier, WA,
Redwood National Park, CA, and the
Cascades of Oregon. In contrast, it
contributes less than 25 percent in
southern California. Organic carbon
typically makes up 20-30 percent of
aerosol light extinction in the rural
Figure 6-66. Aerosol light
extinction in western Class I
areas for the clearest 20
percent of the days in the
distribution, 1989-1998.
Q Organic Carbon
H Nitrate
D Sulfate
• Elemental Carbon
H Crustal Material
Figure 6-6f. Aerosol light
extinction in western Class I
areas for the haziest 20
percent of the days in the
distribution, 1989-1998.
Aerosol Light Extinction, Mm-1
50
40
30
20
10
24 Sites
0 lt=^-
Figure 6-6e. Aerosol light
extinction in western Class I
areas for the middle 20 percent
of the days in the distribution, 40
1989-1998.
30
89 90 91 92 93 94 95
Aerosol Light Extinction, Mm-1
50
97 98
24 Sites
90 91 92 93 94 95 96 97 98
Aerosol Light Extinction, Mm-1
50 , ,
40
30
20
24 Sites
89 90 91 92 93 94 95 96 97 98
98 VISIBILITY TRENDS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Table 6-1. Summary of Class I Area Trend* Analysis
Parameter Number of Sites With
Significant Upward
(Deteriorating) Trends
West East
Number of Sites With
Significant Downward
(Improving) Trends
West East
Deciviews, worst 20%
Deciviews, middle 20%
Deciviews, best 20%
Light extinction due to
sulfate, worst 20%
Light extinction due to
sulfate, middle 20%
Light extinction due to
sulfate, best 20%
Light extinction due to
organic carbon, worst 20%
Light extinction due to
organic carbon, middle 20%
Light extinction due to
organic carbon, best 20%
1
0
1
3
2
1
0
0
•
3
0
0
1
0
0
0
0
0
0
4
3
5
3
1
9
4
6
4
0
3
0
0
3
1
0
0
0
* Based on a total of 34 monitored sites with at least seven years of data: 24 in the west, 10
in the east.
West, elemental carbon (absorption)
accounts for about 10 percent, and
crustal matter (including coarse PM)
accounts for about 15-25 percent.
Nitrates typically account for less
than 10 percent of total light extinc-
tion in western locations, except in
the southern California region, where
it accounts for almost 40 percent.
Figures 6-8a, 6-8b, and 6-8c illus-
trate current levels of visibility im-
pairment, in terms of deciviews, for
the clearest, typical, and haziest 20
percent days based on IMPROVE
data from 1995-19977 Note that the
deciview scale is more compressed
than the scale for visual range or light
extinction, with larger values repre-
senting greater visibility degradation.
Most of the sites in the intermountain
West and Colorado Plateau have
annual average impairment of 12
deciviews or less, with the worst
days ranging up to 16 deciviews.
Several other western sites in the
northwest and California experience
levels on the order of 15-25
deciviews on the haziest 20 percent of
days. Many rural locations in the
East have annual average values
exceeding 23 deciviews, with average
visibility levels on the haziest days
up to 33 deciviews.
Programs to Improve
Visibility
In April of 1999, EPA issued the final
regional haze regulation.8 This regu-
lation addresses visibility impair-
ment in national parks and
wilderness areas that is caused by
numerous sources located over broad
regions. The program lays out a
framework within which states can
work together to develop implemen-
tation plans that are designed to
achieve "reasonable progress" to-
ward the national visibility goal of no
human-caused impairment in the 156
mandatory Class I federal areas
across the country.
States are required to establish
goals to improve visibility on the 20
percent worst days and to allow no
degradation on the 20 percent best
days for each Class I area in the state.
In establishing any progress goal, the
state must analyze the rate of
progress for the next 10-15 year
implementation period which, if
maintained, would achieve natural
visibility conditions by 2064. The
state will need to show whether this
rate of progress or another rate is
more reasonable based on certain
factors in the Clean Air Act, including
costs and the remaining useful life of
affected sources. Along with these
goals, the state plans must also in-
clude emission reduction measures to
meet these goals (in combination
with other states' measures), require-
ments for Best Available Retrofit
Technology on certain large existing
sources (or an alternative emissions
trading program), and visibility
monitoring representative of all class
I areas.
State regional haze plans are due
in the 2003-2008 timeframe. Because
of the common precursors and the
regional nature of the PM and re-
gional haze problems, the haze rule
includes specific provisions for states
that work together in regional plan-
ning groups to assess the nature and
sources of these problems and to
develop coordinated, regional emis-
sion reduction strategies. One provi-
sion allows nine Grand Canyon
Visibility Transport Commission
States (Arizona, California, Colorado,
Idaho, Nevada, New Mexico, Or-
egon, Utah, and Wyoming) to submit
initial plans in 2003 to implement
their past recommendations within
the framework of the national re-
CHAPTER6 • VISIBILITY TRENDS 99
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 6-7a. Aerosol light extinction (in Mm-1) for the clearest 20 percent days and contribution by individual particulate matter
constituents, based on 1995-1997 IMPROVE data.
Species
• Nitrate
Organic Carbon
Elemental Carbon
| Crustal Matter
Sulfate
Figure 6-7b. Aerosol light extinction (in Mm-1) for the middle 20 percent days and contribution by individual particulate matter
constituents, based on 1995-1997 IMPROVE data.
! Species
Nitrate
Organic Carbon
Elemental Carbon
Crustal Matter
jjj2 Sulfate
•
_
11
100 VISIBILITY TRENDS • CHAPTERS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 139B
Figure 6-7c. Aerosol light extinction (in Mm-1) for the haziest 20 percent days and contribution by individual paniculate matter
constituents, based on 1995-1997 IMPROVE data.
Species
HI Nitrate
B Organic Carbon
Elemental Carbon
m Crustal Matter
B71 Sulfate
Figure 6-8a. Current visibility impairment expressed in deciviews for the clearest 20 percent days based on 1995-1997 IMPROVE
data.
CHAPTERS • VISIBILITY TRENDS 101
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 6-8b. Current visibility impairment expressed in deciviews for the middle 20 percent days based on 1995-1997 IMPROVE
data.
Figure 6-8c. Current visibility impairment expressed in deciviews for the haziest 20 percent days based on 1995-1997 IMPROVE
data.
102 VISIBILITY TRENDS • CHAPTER 6
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
gional haze program. Another provi-
sion allows certain states until 2008
to develop coordinated strategies for
regional haze and PM contingent
upon future participation in regional
planning groups.
Implementation of the PM and
Ozone NAAQS in conjunction with a
future regional haze program is ex-
pected to improve visibility in urban
as well as rural areas across the coun-
try. Other air quality programs are
expected to bring about emissions
reductions that will improve visibil-
ity in certain regions of the country.
The acid rain program will achieve
significant regional reductions in the
emissions of SO2/ which will reduce
sulfate haze particularly in the east-
ern United States. When imple-
mented, the NOX State
Implementation Plan (SIP) call to
reduce emissions from sources of
NOx to reduce formation of ozone
should also improve regional visibil-
ity conditions to some degree. In
addition, visibility impairment in
class I areas should improve as a
result of a number of other programs,
including mobile source emissions
and fuel standards, certain air toxics
standards, and implementation of
smoke management and woodstove
programs to reduce fuel combustion
and soot emissions.
References
1. Data from IMPROVE Visibility
Monitoring Network, 1998.
2. PhotoCD images provided by Kris-
ti Savig and John Molenar, Air Re-
source Specialists, Inc., Fort Collins,
Colorado 80525.
3. Sisler, J. Spatial and Seasonal Patterns
and Long-Term Variability of the Composi-
tion of the Haze in the United States: An
Analysis of Data from the IMPROVE
Network. Colorado State University,
Cooperative Institute for Research in
the Atmosphere. Fort Collins, CO.,
1996.
Also see: Sisler, J., Huffman, D., and
Latimer, D. Spatial and Temporal Pat-
terns and the Chemical Composition of the
Haze in the United States: An Analysis of
Data from the IMPROVE Network, 1988-
1991, Colorado State University, Coop-
erative Institute for Research in the
Atmosphere. Fort Collins, CO., 1993.
Also see (Submitted for publication)
James F. Sisler, and William C. Malm,
"Interpretation of Trends of PM25 and
Reconstructed Visibility from the IM-
PROVE Network," Journal of the Air
and Waste Management Association,
1998.
4. Irving, Patricia M., ed., Acid Deposi-
tion: State of Science and Technology,
Volume III, Terrestrial, Materials, Health,
and Visibility Effects, The U.S. National
Acid Precipitation Assessment Pro-
gram, Chapter 24, page 24-76.
5. R. B. Husar, J. B. Elkins, WE . Wil-
son, "U.S. Visibility Trends, 1906-
1992," Air and Waste Management
Association 87lh Annual Meeting and
Exhibition, Cincinnati, OH, 1994.
6. See reference 1.
7. See reference 1.
8. The final regional haze rule was
signed on 4/22/99 and published in
the Federal Register on 7/1/99 (64 Fed-
eral Register 35723).
CHAPTERS • VISIBILITY TRENDS 103
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
104 VISIBILITY TRENDS • CHAPTERS
-------
CHAPTER 7
Atmospheric Deposition of
Sulfur and Nitrogen
Compounds
http://wwwiepa.gov/oar/aqtrncl98/ch9pter7.pdf
Sulfur and nitrogen oxides are emit-
ted into the atmosphere primarily
from the burning of fossil fuels.
These emissions react in the atmo-
sphere to form compounds that are
transported long distances and are
subsequently deposited in the form
of pollutants such as particulate mat-
ter (sulfates, nitrates) and related
gases (nitrogen dioxide, sulfur diox-
ide and nitric acid). Nitrogen oxides
will also interact with volatile organic
compounds to form ozone. The ef-
fects of atmospheric deposition include
acidification of lakes and streams,
nutrient enrichment of coastal waters
and large river basins, soil nutrient
depletion and decline of sensitive for-
ests, agricultural crop damage, and
impacts on ecosystem biodiversity.
Toxic pollutants and metals can also
be transported and deposited
through atmospheric processes. (See
Chapter 5: Air Toxics.)
Both local and long-range emis-
sion sources contribute to atmo-
spheric deposition. Total atmospheric
deposition is determined using both
wet and dry deposition measure-
ments. Wet deposition is the portion
dissolved in cloud droplets and is
deposited during rain or other forms
of precipitation. Dry deposition is
the portion deposited on dry surfaces
during periods of no precipitation as
particles or in a gaseous form. Al-
though the term "acid rain" is widely
recognized, the dry deposition por-
tion can range from 20-60 percent of
total deposition.
EPA is required by several Con-
gressional and other mandates to
assess the effectiveness of air pollu-
tion control efforts. These mandates
include Title IX of the Clean Air Act
Amendments (the National Acid
Precipitation Assessment Program),
the Government Performance and
Results Act, and the U.S./Canada Air
Quality Agreement. One measure of
effectiveness of these efforts is
whether sustained reductions in the
amount of atmospheric deposition
over broad geographic regions are
occurring. However, changes in the
atmosphere happen very slowly and
trends are often obscured by the wide
variability of measurements and •
climate. Numerous years of continu-
ous and consistent data are required
to overcome this variability, making
long-term monitoring networks espe-
' daily critical for characterizing depo-
sition levels and identifying
relationships among emissions, at-
mospheric loadings and effects on
human health and the environment.
For wet and dry deposition, these
studies typically include measure-
ment of concentration levels of key
chemical components as well as pre-
cipitation amounts. For dry deposi-
tion, analyses must also include
meteorological measurements that
are used to estimate rate of the actual
deposition, or "flux." Data represent-
ing total deposition loadings (e.g.,
total sulfate or nitrate) are what
many environmental scientists use
for integrated ecological assessments.
Primary Atmospheric
Deposition Monitoring
Networks
The National Atmospheric Deposi-
tion Program (NADP) and the Clean
Air Status and Trends Network
(CASTNet) were developed to moni-
tor wet and dry acid deposition,
respectively. Monitoring site loca-
tions are predominantly rural by
design to assess the relationship
between regional pollution and
changes in regional patterns in depo-
sition. CASTNet also includes mea-
surements of rural ozone and the
CHAPTER? • ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS 105
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 7-1. The NADP/NTN Network.
chemical constituents of PM25. Rural
monitoring sites of NADP and CAST-
Net provide data where sensitive
ecosystems are located and provide
insight into natural background lev-
els of pollutants where urban influ-
ences are minimal. These data
provide needed information to scien-
tists and policy analysts to study and
evaluate numerous environmental
effects, particularly those caused by
regional sources of emissions for
which long range transport plays an
important role. Measurements from
these networks are also important for
understanding non-ecological im-
pacts of air pollution such as visibili-
ty impairment and damage to
materials, particularly those of cul-
tural and historical importance.
National Atmospheric Deposition
Network
The National Atmospheric Deposi-
tion Program (NADP) was initiated
in the late 1970s as a cooperative
program between federal and state
agencies, universities, and electric
utilities and other industries to deter-
mine geographical patterns and
trends in precipitation chemistry in
the United States. Collection of
weekly wet deposition samples be-
gan in 1978. The size of the NADP
Network grew rapidly in the early
1980s when the major research effort
by the National Acid Precipitation
Assessment Program (NAPAP) called
for characterization of acid deposi-
tion levels. At that time, the network
became known as the NADP/NTN
(National Trends Network). By the
mid-1980s, the NADP had grown to
nearly 200 sites, where it stands to-
day as the longest running national
deposition monitoring network (see
Figure 7-1).
The NADP analyzes the constitu-
ents important in precipitation chem-
istry, including those affecting
rainfall acidity and those that may
have ecological effects. The Network
measures sulfate, nitrate, hydrogen
ion (measure of acidity), ammonia,
chloride, and base cations (calcium,
magnesium, potassium). To ensure
comparability of results, laboratory
analyses for all samples are con-
ducted by NADP's Central Analyti-
cal Lab at the Illinois State Water
Survey. A new subnetwork of the
NADP, the Mercury Deposition Net-
work (MDN) measures mercury in
precipitation. For more information on
the MDN, see Chapter 5: Air Toxics.
106 ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS • CHAPTER 7
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 7-2. Percent differences in mean annual measured sulfate concentrations as compared to projected concentrations for
1995-1996 for the eastern United States (from NADP/NTN).
Small squares on the map show locations
of electric utility plants affected under
Phase I of the Acid Rain Program. Areas
on the map depicting higher sulfate
concentrations (e.g., south and east of
Lake Michigan and the southwestern
portion of map) appear to be due to below
average precipitation volumes, which are
associated with higher concentrations of
sulfate. In addition, these results may
have been affected by SO2 emission
increases at some Phase II emissions
sources that are controlled by the Acid
Rain Program in the year 2000.
-20
Trends Analyses for
Sulfate and Nitrate
Concentrations in Wet
Deposition
Sulfate concentrations in precipita-
tion have decreased over the past
two decades.1 The reductions were
relatively large in the early 1980s
followed by more moderate declines
until 1995. These reductions in wet
sulfates are similar to changes in SO2
emissions. In 1995 and 1996, howev-
er, concentrations of sulfates in pre-
cipitation over a large area of the
eastern United States exhibited a
dramatic and unprecedented reduc-
tion. Sulfates have been estimated to
be 10-25 percent lower than levels
expected with a continuation of
1983-1994 trends (see Figure 7-2).
This important reduction in acid
precipitation is directly related to the
large regional decreases in SO2 emis-
sions resulting from phase I of the
Table 7-1. Mean Annual Sulfate Wet Deposition, 1989-1998, in Three Sensitive
Regions in the Eastern United States
Mean Annual
Sulfate Wet
Deposition (kg/ha)
Percent Change in Mean
Annual Sulfate Wet
Deposition
Region
Adirondacks
Mid-Appalachian
Southern Blue Ridge
(1989-91 1995-98)
25.6 18.9
27.3 21 .4
22.9 19.6
(1989-91 to 1995-98)
-26
-21
-15
Acid Rain Program (See "Trends in
SO2" in Chapter 2 of this report). The
largest reductions in sulfate concen-
trations occurred along the Ohio
River Valley and in states immediate-
ly downwind of this region. For
example, the average reduction in
sulfate concentrations in Ohio was
approximately 21 percent, in Mary-
land 27 percent, and in Pennsylvania
15 percent. The largest decrease (32
percent) occurred in the northern
portion of West Virginia. Reductions
in hydrogen ion concentrations in the
East, the primary indicator of precipi-
tation acidity, were very similar to
those of sulfate concentrations, both
in magnitude and location. Nitrate
concentrations at NADP/NTN sites
were not appreciably different in
1995-1996 from historical levels.2
The effects of decreased SO2 emis-
sions on sulfates can also be seen by
comparing deposition maps for the
eastern United States. Figures 7-3a
and 7-3b compare wet sulfate deposi-
tion between 1989-1991 and 1995-
1998.3 The sulfate concentrations in
CHAPTER 7 • ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS 107
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
precipitation are still highest in the
Great Lake states and areas extend-
ing eastward, but the magnitude of
the levels are greatly reduced.
The percent improvement between
1989-1991 and 1995-1998 can also be
viewed in terms of three sensitive
regions in the eastern United States:
Adirondacks, Mid-Appalachians,
and Southern Blue Ridge. Table 7-1
shows that the improvements range
from 15-26 percent. The largest im-
provements were in the Adirondacks
and Mid-Appalachians.3
Clean Air Status and Trends
Network
The Clean Air Status and Trends
Network provides atmospheric data
on the dry deposition component of
total acid deposition, ground-level
ozone and other forms of atmos-
pheric pollution. CASTNet is consid-
ered the nation's primary source for
atmospheric data to estimate dry
acidic deposition and to provide data
on rural ozone levels. Used in conjunc-
tion with other national monitoring
networks, CASTNet is used to deter-
mine the effectiveness of national
emission control programs. Estab-
lished in 1987, CASTNet now com-
prises 79 monitoring stations across
the United States. The longest data
records are primarily at eastern sites.
The majority of the monitoring sta-
tions are operated by EPA's Office of
Air and Radiation; however, 27 sta-
tions are operated by the National
Park Service (NFS) in cooperation
with EPA. Of the total number of
sites, 74 measure dry-deposition, 19
measure wet-deposition, 68 measure
ozone, and eight measure aerosols for
visibility assessment.
Each CASTNet dry deposition
station measures:
Figure 7-3a. Trends in wet sulfate deposition (kg/ha); 1995-1997.
Figure 7-3b. Trends in wet sulfate deposition (kg/ha); 1989-1991.
108 ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS • CHAPTER 7
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 7-4. CASTNet Network and subset of 34 sites used for 1989-1998 trends analysis.
• used for 1989-1998 trends analysis.
• Weekly average atmospheric
concentrations of sulfate, nitrate,
ammonium, sulfur dioxide, and
nitric acid (sulfate, nitrate and am-
monium generally exist as fine
particles).
• Hourly concentrations of ambient
ozone levels.
• Meteorological conditions re-
quired for calculating dry deposi-
tion rates.
Dry Deposition
Dry deposition rates are calculated
using atmospheric concentrations,
meteorological data and information
on land use, vegetation, and surface
conditions. CASTNet complements
the database compiled by NADP.
Because of the interdependence of
wet and dry deposition, CASTNet
also collected wet deposition data at
the 18 sites where there are no
NADP/NTN stations within a 50 km
radius. Now, these sites are officially
part of the NADP. Together, these
two long-term databases provide the
necessary data to estimate trends and
spatial patterns in total atmospheric
deposition. NOAA also operates a
smaller dry deposition network
called Atmospheric Integrated As-
sessment Monitoring Network (AIR-
MoN) focused on addressing
research issues specifically related to
dry deposition measurement.
Concentration Trends Analysis at
CASTNet Sites
CASTNet ambient concentration data
in the eastern United States were
analyzed for the period 1989 to 1998
for the change in ambient sulfur diox-
ide, sulfates, total nitrates and ammo-
nium. First, maps are presented for a
comparison of 2-year periods at the
beginning and end of the 10-year
period based on data from all 50
eastern locations in the CASTNet
monitoring program. Then data from
a subset of 34 Eastern CASTNet sites
with the most complete historical
record are examined for year to year
changes from 1989 to 1998.5
In the early 1990s, ambient SO2
concentrations in the rural eastern
United States were highest in western
Pennsylvania, along the Ohio Valley
and in the vicinity of Chicago/Gary
Indiana. Large improvement in SO2
air quality can be seen by comparing
1990-1991 with 1997-1998. The larg-
est decreases in concentrations are
noted in the vicinity of Chicago and
throughout the states bordering the
Ohio VaUey (IL, IN, OH, PA, KY,
WV). The highest SO2 concentrations
in the rural parts of the eastern
United States are now concentrated
in southwestern PA.
In the early 1990s, sulfate concen-
trations greater than 5 ug/m3* cover
CHAPTER? . ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS 1O9
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 7-5a. Comparison of ambient sulfur dioxide concentrations in the rural eastern United States from CASTNet monitoring data,
1990-1991 vs. 1997-1998
1990-1991
1997-1998
Decrease in ambient sulfur dioxide
concentrations in the rural eastern United
States, 1990-1991 vs. 1997-1998.
most of the eastern United States.
Regions of concentrations greater
than 6 pg/m3 are estimated to cover
the Ohio Valley States (II, IN, OH,
KY, WV), PA and the other mid-At-
lantic states from New Jersey to Vir-
ginia. The highest sulfate
concentrations (> 7 pg/m3) were
adjacent to the Ohio Valley and in
northern Alabama. These are the
locations of large electric utilities.
In the late 1990s (represented by
the period 1997-1998), sulfates were
dramatically lower. Although there
are differences between 1997 and
1998, as discussed below, both the
size of the region with and the mag-
nitude of the highest concentrations
has decreased. However, the region
with concentrations higher than 5
ug/m3 does not appear to have
changed appreciably.
The location of all CASTNet sites
and those used for the 10-year trend
analysis are shown in Figure 7-4.
During this 10-year period, atmo-
spheric concentrations of SO2 and
sulfate both showed statistically-
significant declining trends. The
average reduction in the these rural
sulfur dioxide and sulfate levels was
38 percent** and 22 percent respec-
tively. The distribution of annual
average concentrations is presented
as box-plots in Figures 7-6 and 7-7.
An average 10-percent increase in
sulfates between 1997 and 1998 is
also noted.
The trend in total nitrate concen-
trations (nitrates plus nitric acid) was
essentially flat, corresponding to the
small change in NOX emissions dur-
ing this period. The highest nitrate
concentrations are found in the States
of Ohio, Indiana and Illinois.
Ammonium concentrations in the
ambient air are typically associated
with sulfate and nitrate compounds.
The ammonium maps presented in
Figure 7-5d show that the highest
ammonium concentrations are also
highest in the midwest. However, the
decrease in ambient ammonium over
the 10-year period primarily occurred
in the Ohio Valley and appears to be
associated with the reduction in sul-
fate concentrations.
Electric utilities account for 71
percent of the SO2 emissions in the
eastern United States. However, they
accounted for most of the nationwide
reduction in SO2 emissions.7 The
trend in ambient sulfates and sulfur
"Sulfate concentrations represent the
sulfate ion, SO4-2, and do not represent the
compounds (i.e., ammonium sulfate or
ammonium bisulfate) typically associated
with this analyte.
"The overall 38-percent decline in ambi-
ent SO2 concentrations in rural areas matches
the national air quality improvement in
urban areas as measured by the state and
local air monitoring stations.
110 ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS • CHAPTER 7
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 7-5b. Comparison of ambient sulfate concentrations in the rural eastern United States from CASTNet monitoring data,
1990-1991 vs. 1997-1998.
1990-1991
1997-1998
Decrease in ambient sulfate
concentrations in the rural eastern United
States, 1990-1991 vs. 1997-1998.
Figure 7-5c. Comparison of ambient total nitrate concentrations in the rural eastern United States from CASTNet data,
1990-1991 vs. 1997-1998.
1990-1991
1997-1998
Decrease in ambient total nitrate
concentrations in the rural eastern United
States, 1990-1991 vs. 1997-1998.
CHAPTER? • ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS 111
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 7-5d. Comparison of ambient ammonium concentrations in the rural eastern United States from CASTNet data,
1990-1991 vs. 1997-1998.
1990-1991
1997-1998
Decrease in ambient ammonium
concentrations in the rural eastern United
States, 1990-1991 vs. 1997-1998.
dioxide are generally consistent with
the change in annual sulfur dioxide
emissions from electric utilities in the
eastern United States. Figure 7-8
shows that the 22 percent 10-year
decline in sulfates matches the over-
all 21-percent decline in SO2 emis-
sions. In addition, the 1997-1998
increase in ambient sulfates (10 per-
cent) appears to follow the 5-percent
increase in annual emissions.
Figure 7-9 presents the trends in
ambient sulfates, ambient sulfur
dioxide, and SO2 emissions by calen-
dar quarter. Most of the increase in
emissions and ambient sulfates oc-
curred during the high sulfate "sea-
son" (i.e., the 2"d and 3r^ calendar
quarters). This season with its slow
moving ah masses and high photo-
chemical activity contributes 65-70
percent to the typical annual average
Figure 7-6. Trend in ambient sulfates in the rural eastern United States, based on
CASTNet monitoring data, 1989-1998.
Concentration (ug/m )
10-
8-
6-
4-
- 90th Percentile
- Mean
— Median
—I - 10th Percentile
34 Sites
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
112 ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS • CHAPTER 7
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure 7-7. Trend in ambient sulfur dioxide in the rural United States, based on
CASTNet monitoring data, 1989-1998.
Concentration (ug/m3)
30-
20-
10-
- 90th Percentile
- Mean
— Median
- 10th Percentile
34 Sites
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Figure 7-8. Trend in annual average ambient sulfur dioxide and sulfate
concentrations, based on CASTNet monitoring data, and regional SO2 emissions from
electric utilities in rural eastern United States, 1989-1998.
10
2 occurred during these quarters.
From 1989-1998, the 6-cold-month
average SO2 concentrations (now
accounting for 60-65 percent of the
annual average) decreased 44 per-
cent. The 10-year decline in emis-
sions, -29 percent, was also greater
during the colder months. During
the last two years, annual average
SO2 decreased while annual emis-
sions increased. However, air quality
and emissions match more closely on
a seasonal basis. During the cold
months, average SO2 concentrations
and total emissions increased slightly
in the 1st quarter but decreased dur-
ing the latter part of the year. For the
warmer months (the 2nd and 3rd cal-
endar quarters), the figure reveals a
large increase in SO2 emissions, am-
CHAPTER7 • ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS 113
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
bient sulfates and ambient sulfur
dioxide between 1997 and 1998 dur-
ing. (See the criteria pollutants sec-
tion in Chapter 2 for more
information about SO2 emission
trends and the acid rain program.
Also see www.epa.gov/acidrain/).
References
1 . Lynch, J. A., J.W. Grim and V.C
Bowersox. 1995. Trends in Precipitation
Chemistry in the United States: A Nation-
al Perspective, 1980-1992. Atmospheric
Environment Vol 29, No. 11.
2. Lynch, J.A., V.C Bowersox and J.W.
Grim. 1996. Trends in Precipitation
Chemistry in the United States: An Anal-
ysis of the Effects in 1995 of Phase I of the
Clean Air Act Amendments of 1990, Title
IV. U.S. Geological Survey. Open-file
Report 96-0346.
3. "Changes in Sulfate Deposition in
the Eastern USA Following Enactment
of Title IV of the Clean Air Act Amend-
ments of 1990." Lynch, J.A., Bowersox,
V.C. and Grimm, J.W., 1999. Atmospher-
ic Environment. In Press.
4. Holland, D. P. Principe and J. Sick-
Figure 7-9a. Trend in annual average ambient sulfur dioxide and sulfate
concentrations, based on CASTNet monitoring data, and regional SO2 emissions from
electric utilities in rural eastern United States by calendar quarter, 1989-1998; quarter 1.
10
O) o
-3=
CO
§ 7
§
o
si
3 r,
CO O
"CO
C o
o 2
'ra
CD .
CC 1
Sulfate concentrations ~——
20 -T-5
"E
15
89 90 91 92 93 94 95 96 97 98
CO
o
'
10 §
o
o
o
O
CO
5 —
co
g
"DJ
CD
DC
0 -1-0
CO
o
o
CO
o
CO
g
'co
CO
E
0)
CM
o
CO
15
g
'o
cu
Figure 7-9b. Trend in annual average ambient sulfur dioxide and sulfate
concentrations, based on CASTNet monitoring data, and regional SO2 emissions from
electric utilities in rural eastern United States by calendar quarter, 1989-1998; quarter 2.
ies, u. ivyo. in press, sicmospneric envi-
ronment.
5. Clean Air Status and Trends Net-
work (CASTNet), 1998 Annual Report.
6. The overall 38-percent decline in
ambient SO2 concentrations in rural
areas matches the national air quality
improvement in urban areas as mea-
sured by the State and local ah- moni-
toring stations.
7. Eighty-four percent of the 10-year
nationwide reduction in SO2 emissions
is attributed to fuel combustion from
electric utilities.
CO
.£
CO
c
0
'•5
v_.
8
o
js
CO
15
.0
O3
0)
a:
10
I \J
9
8
7
/
6
5
4
3
2
1
n
\j
, - _ _,
Sulfate concentrations
\ ^c^.
..v,x'. - . .^^^---^ __^ .. ...
SO2 emissions ~~~\ \ .
^ N \ ^-'
~~—~~^§Oz concentrations
N. _— -—
. - .>---"""""''
89 90 91 92 93 94 95 96 97 98
on
CO™"*"
E
15 g
'*.^t-
CO
"4=
ti
10 g
O
c
8
CJ
O
CO
5 lo
c
o
CD
rr
o
o
-c
0
CO
c
.0
1,
CO
c
o
CO
0
o"
CO
"CD
.0
CD
n
114 ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS • CHAPTER 7
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Figure 7-9c. Trend in annual average ambient sulfur dioxide and sulfate
concentrations, based on CASTNet monitoring data, and regional SO2 emissions from
electric utilities in rural eastern United States by calendar quarter, 1989-1998; quarter 3.
10
- 9
CO
c 7
fj
8 K
§ 5
o
CO «3
To
C o
g 2
"en
CD .
CC 1
_ Sulfate concentrations
\
\
SOP emissions x
/
SO2 concentrations
-1-5
15
CO
o
89 90 91 92 93 94 95 96 97 98
10 §
o
o
o
O
CO
5 To
CD
CC
0 —0
co
c:
jo
•e
o
c
o
CO
o
'co
w
"E
CD
CM
o
CO
"CD
o
'
Figure 7-9d. Trend in annual average ambient sulfur dioxide and sulfate
concentrations, based on CASTNet monitoring data, and regional SO2 emissions from
electric utilities in rural eastern United States by calendar quarter, 1989-1998; quarter 4.
10
co"~* y
O) o
3. 8
CO
CD
§5
O
CD 4
JJ
"co
c: o
o 2
'en
CD .
DC 1
-\-._ JSO2 emissions
SO2 concentrations
Sulfate concentrafidns~
20 -,-5
15 §>
CO
.0
10
89 90 91 92 93 94 95 96 97 98
o
o
CD-
CO
5 7J
g
'en
CD
o:
0 —0
CO
I
•e
o
CO
o
CO
g
'co
CO
CD
O
CO
75
o
'en
0
CfL
CHAPTER? • ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS 115
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
116 ATMOSPHERIC DEPOSITION OF SULFUR AND NITROGEN COMPOUNDS • CHAPTER 7
-------
APPENDIX A
Data Tables
http://www.epa.gov/oar/aqtrnd98/appenda.pdf
APPENDIX A • DATA TABLES 117
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-1. National Air Quality Trends Statistics for Criteria Pollutants, 1989-1998
Statistic
Carbon Monoxldt
2nd Max. 8-hr.
2nd Max. 8-hr.
2nd Max. 8-hr.
2nd Max. 8-hr.
2nd Max. 8-hr.
2nd Max. 8-hr.
2nd Max. 8-hr.
2nd Max. 8-hr.
Lead
Max. Qlr. AM
Max. Qtr. AM
Max. Qtr. AM
Max. Qtr. AM
Max. Qtr. AM
Max. Qtr. AM
Max. Qtr. AM
Max. Qtr. AM
Nitrogen Dioxide
Arilh. Mean
Arith. Mean
Arith. Mean
Arith. Mean
Arilh. Mean
Arith. Mean
Arith. Mean
Arith. Mean
Ozone
2nd Max. 1-hr.
2nd Max. 1-hr.
2nd Max. 1-hr.
2nd Max. 1-hr.
2nd Max. 1-hr.
2nd Max. 1-hr.
2nd Max. 1-hr.
2nd Max. 1-hr.
4th Max. 8-hr.
4th Max. 8-hr.
4th Max. 8-hr.
4th Max. 8-hr.
4th Max. 8-hr.
4th Max. 8-hr.
4th Max. 8-hr.
4th Max. 8-hr.
# of Sites
?
363
363
363
363
363
363
363
363
189
189
189
189
189
189
189
189
225
225
225
225
225
225
225
225
661
661
661
661
661
661
661
661
661
661
661
661
661
661
661
661
Units
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
Percentile
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
1989
10.9
9.7
7.7
5.9
4.4
3.4
2.6
6.2
0.27
0.17
0.11
0.06
0.03
0.03
0.02
0.09
0.043
0.035
0.027
0.020
0.013
0.007
0.005
0.021
0.171
0.150
0.124
0.107
0.095
0.085
0.080
0.114
0.117
0.105
0.093
0.083
0.075
0.067
0.060
0.086
1990
10.5
8.8
7.0
5.4
4.2
3.1
2.5
5.8
0.35
0.16
0.09
0.05
0.03
0.02
0.01
0.09
0.040
0.034
0.025
0.019
0.013
0.007
0.005
0.020
0.170
0.146
0.120
0.107
0.095
0.083
0.075
0.112
0.116
0.106
0.094
0.083
0.075
0.066
0.059
0.085
1991
9.8
8.7
7.0
5.2
3.9
3.0
2.3
5.6
0.21
0.15
0.07
0.04
0.03
0.01
0.01
0.07
0.043
0.033
0.025
0.019
0.012
0.007
0.005
0.020
0.170
0.149
0.124
0.108
0.095
0.081
0.075
0.113
0.116
0.109
0.097
0.085
0.073
0.065
0.059
0.086
1992
8.5
7.8
6.4
4.8
3.7
2.8
2.4
5.2
0.18
0.13
0.06
0.04
0.02
0.01
0.01
0.06
0.038
0.033
0.024
0.018
0.013
0.007
0.005
0.019
0.160
0.131
0.111
0.100
0.090
0.081
0.074
0.105
0.107
0.097
0.087
0.079
0.073
0.066
0.061
0.081
1993
8.0
7.2
5.9
4.7
3.6
2.9
2.2
4.9
0.18
0.11
0.06
0.03
0.02
0.01
0.01
0.05
0.037
0.033
0.024
0.018
0.013
0.007
0.005
0.019
0.150
0.138
0.120
0.104
0.091
0.080
0.075
0.108
0.110
0.100
0.090
0.081
0.073
0.063
0.058
0.082
1994
8.1
7.6
6.2
4.9
3.8
2.8
2.2
5.1
0.14
0.10
0.05
0.03
0.02
0.01
0.01
0.05
0.040
0.034
0.024
0.019
0.013
0.008
0.005
0.020
0.150
0.130
0.117
0.104
0.092
0.083
0.077
0.107
0.106
0.098
0.090
0.082
0.074
0.067
0.060
0.083
1995
7.6
6.6
5.5
4.3
3.3
2.5
2.3
4.5
0.14
0.09
0.05
0.03
0.02
0.01
0.01
0.04
0.039
0.032
0.023
0.019
0.012
0.007
0.005
0.019
0.150
0.139
0.123
0.110
0.098
0.085
0.078
0.112
0.112
0.106
0.096
0.088
0.077
0.067
0.061
0.087
1996
7.4
6.5
5.1
3.9
3.0
2.3
2.0
4.2
0.13
0.09
0.04
0.02
0.01
0.01
0.01
0.04
0.037
0.032
0.024
0.018
0.012
0.007
0.004
0.019
0.144
0.127
0.114
0.103
0.093
0.085
0.079
0.106
0.103
0.097
0.090
0.083
0.075
0.068
0.063
0.083
1997
6.7
5.9
4.9
3.8
2.9
2.1
1.7
3.9
0.12
0.09
0.04
0.02
0.01
0.01
0.01
0.04
0.034
0.031
0.022
0.018
0.012
0.007
0.004
0.018
0.142
0.130
0.116
0.103
0.091
0.081
0.075
0.105
0.105
0.101
0.091
0.082
0.074
0.065
0.059
0.083
1998
6.3
5.7
4.6
3.5
2.7
2.1
1.9
3.8
0.13
0.08
0.04
0.02
0.01
0.01
0.01
0.04
0.035
0.031
0.023
0.018
0.012
0.006
0.004
0.018
0.154
0.134
0.119
0.109
0.096
0.086
0.076
0.110
0.110
0.102
0.095
0.087
0.077
0.069
0.060
0.086
118 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-1. National Air Quality Trends Statistics for Criteria Pollutants, 1989-1998 (continued)
Statistic
'PM
.w
Annual Avg.
Annual Avg.
Annual Avg.
Annual Avg.
Annual Avg.
Annual Avg.
Annual Avg.
Annual Avg.
Sulfur Dioxide
Annual Mean
Annual Mean
Annual Mean
Annual Mean
Annual Mean
Annual Mean
Annual Mean
Annual Mean
2nd Max. 24-hr.
2nd Max. 24-hr.
2nd Max. 24-hr.
2nd Max. 24-hr.
2nd Max. 24-hr.
2nd Max. 24-hr.
2nd Max. 24-hr.
2nd Max. 24-hr.
# of Sites
934
934
934
934
934
934
934
934
482
482
482
482
482
482
482
482
486
486
486
486
486
486
486
486
Units
ug/m3
ug/m3
ug/m3
ug/m3
ug/m3
ug/m3
ug/m3
ug/m3
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
Percentile
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
95th
90th
75th
50th
25th
10th
5th
Arith. Mean
1989
51.5
43.3
36.3
30.1
25.3
20.1
17.1
31.7
0.0183
0.0153
0.0115
0.0080
0.0048
0.0024
0.0016
0.0087
0.0960
0.0740
0.0520
0.0380
0.0230
0.0110
0.0070
0.0414
1990
46.4
39.8
34.5
28.2
23.4
18.9
15.7
29.4
0.0175
0.0146
0.0107
0.0077
0.0044
0.0022
0.0015
0.0082
0.0870
0.0660
0.0480
0.0330
0.0210
0.0100
0.0060
0.0375
1991
46.4
39.9
33.7
28.2
23.6
18.4
14.5
29.1
0.0162
0.0138
0.0099
0.0076
0.0046
0.0022
0.0016
0.0079
0.0750
0.0610
0.0440
0.0320
0.0200
0.0100
0.0070
0.0348
1992
42.0
36.4
31.0
25.8
22.0
17.6
13.6
26.8
0.0154
0.0128
0.0095
0.0069
0.0043
0.0020
0.0014
0.0074
0.0750
0.0610
0.0440
0.0300
0.0190
0.0100
0.0060
0.0339
1993
41.5
35.9-
30.2
25.4
21.0
16.7
12.7
26.0
0.0153
0.0126
0.0092
0.0067
0.0040
0.0022
0.0015
0.0072
0.0720
0.0580
0.0420
0.0280
0.0180
0.0100
0.0055
0.0324
1994
39.4
36.4
30.4
25.6
21.1
16.7
13.1
26.0
0.0143
0.0122
0.0090
0.0065
0.0037
0.0021
0.0015
0.0069
0.0720
0.0620
0.0440
0.0320
0.0190
0.0090
0.0050
0.0340
1995
38.8
34.8
29.1
24.3
19.8
15.5
12.2
24.9
0.0115
0.0101
0.0074
0.0051
0.0033
0.0018
0.0014
0.0056
0.0555
0.0470
0.0330
0.0220
0.0150
0.0080
0.0050
0.0257
1996
37.6
33.0
27.7
23.2
19.3
16.0
12.2
23.9
0.0113
0.0097
0.0074
0.0053
0.0032
0.0018
0.0014
0.0056
0.0600
0,0470
0.0330
0.0230
0.0150
0.0090
0.0050
0.0262
1997
37.5
32.4
27.3
23.2
19.4
15.3
12.1
23.8
0.0107
0.0090
0.0071
0.0051
0.0031
0.0018
0.0014
0.0054
0.0520
0.0450
0.0330
0.0230
0.0140
0.0070
0.0050
0.0250
1998
35.8
31.8
27.7
23.6
19.3
15.2
12.3
23.7
0.0106
0.0095
0.0069
0.0049
0.0032
0.0019
0.0014
0.0053
0.0520
0.0430
0.0310
0.0220
0.0140
0.0080
0.0050
0.0240
APPENDIX A
DATA TABLES
119
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-2. National Carbon Monoxide Emissions Estimates, 1989-1998 (thousand short tons)
Source Category
FUEL COMBUSTION
Electric Utilities
Coal
Oil
Gas
Internal Combustion
Industrial
Coal
Oil
Gas
Other
Internal Combustion
Other
Residential Wood
Other
INDUSTRIAL PROCESSES
Chemical & Allied Processing
Metals Processing
Petroleum & Related Industries
Other Industrial Processes
Solvent Utilization
Storage & Transport
Waste Disposal & Recycling
TRANSPORTATION
On-Road Vehicles
Non-Road Sources
MISCELLANEOUS
Fires
Other
TOTAL ALL SOURCES
1989
7,443
321
233
26
51
11
672
87
46
271
173
96
6,450
6,161
153
7,013
1,925
2,132
436
716
2
55
1,747
83,829
66,050
17,779
8,153
8,153
0
106,439
1990
5,510
363
234
20
51
57
879
105
74
226
279
195
4,269
3,78?
262
5,852
1,183
2,640
333
537
5
76
1,079
76,039
57,848
18,191
11,122
11,090
32
98,523
1991
5,856
349
234
19
51
45
920
101
60
284
267
208
4,587
4,090
281
5,740
1,127
2,571
345
548
5
28
1,116
80,659
62,074
18,585
8,618
8,589
28
100,872
1992
6,155
350
236
15
51
47
955
102
64
300
264
227
4,849
4,332
292
5,683
1,112
2,496
371
544
5
17
1,138
78,858
59,859
18,999
6,934
6,904
30
97,630
1993
5,587
363
246
16
49
51
1,043
101
66
322
286
268
4,181
3,679
274
5,898
1,093
2,536
371
594
5
51
1,248
79,593
60,202
19,391
7,082
7,048
34
98,160
1994
5,519
370
247
15
53
55
1,041
100
66
337
287
251
4,108
3,607
268
5,838
1,171
2,475
338
600
5
24
1,225
81,629
61,833
19,796
9,657
9,628
29
102,643
1995
5,934
372
250
10
55
58
1,056
98
, 71
345
297
245.
4,506
3,999
273
5,790
1,223
2,380
348
624
6
25
1,185
74,331
54,106
20,224
7,298
7,270
29
93,353
1996
6,148
391
248
11
79
54
1,154
109
60
335
349
301
4,603
4,200
260
4,692
1,100
1,429
356
600
2
78
1,127
73,494
53,262
20,232
11,144
11,121
23
95,479
1997
5,423
405
254
12
83
56
1,126
108
58
334
333
295
3,892
3,487
257
4,844
1,119
1,510
369
623
2
80
1,141
71,980
51,666
20,314
12,164
12,141
24
94,410
1998
5,374
417
254
17
89
57
1,114
105
56
330
335
289
3,843
3,452
247
4,860
1,129
1,495
368
632
2
80
1,154
70,300
50,386
19,914
8,920
8,896
24
89,454
Note: Some columns may not sum to totals due to rounding.
120 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-3. National Lead Emissions Estimates, 1989-1998 (short tons)
Source Category
FUEL COMBUSTION
Electric Utilities :
Coal
Oil
Industrial
Coal
Oil
Other
Commercial/Institutional Coal
Commercial/Institutional OH
Misc. Fuel Comb. (Except Residential)
Residential Other
INDUSTRIAL PROCESSES
Chemical & Allied Processing
Metals Processing
Other Industrial Processes
Waste Disposal & Recycling
TRANSPORTATION
On-Road Vehicles
Non-Road Sources
TOTAL ALL SOURCES
1989
505
67
46
21
18
14
4
420
4
4
400
12
3,161
136
2,088
173
765
1,802
982
820
5,468
1990
500
64
46
18
18
14
3
418
4
4
400
10
3,278
136
2,170
169
804
1,197
421
776
4,975
1991
495
. 61
46
15
18
15
3
416
3
4
400
9
3,081
132
1,974
167
808
592
18
574
4,169
1992
491
59
47
12
18
14
4
414
4
4
400
7
2,736
93
1,774
56
812
584
18
565
3,810
1993
497
62
50
12
19
14
5
416
4
4
400
8
2,872
92
1,900
55
825
547
19
529
3,916
1994
496
62
50
12
19
14
5
415
3
4
400
8
3,007
96
2,027
54
830
544
19
525
4,047
1995
490
57
50
7
18
14
4
415
4
3
400
a
2,875
163
2,049
59
604
564
19
544
3,929
1996
492
61
53
8
16
13
3
415
5
3
400
7
2,882
167
2,055
51
609
525
19
505
3,899
1997
493
64
54
10
16
14
2
413
' 5
2
400
6
2,937
188
2,080
54
615
523
20
503
3,952
1998
503
68
54
14
19
13
5
416
5
4
400
6
2,948
175
2,098
54
620
522
19
503
3,973
Note: Some columns may not sum to totals due to rounding.
APPENDIX A • DATA TABLES 121
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-4. National Nitrogen Oxides Emissions Estimates, 1989-1998 (thousand short tons)
Source Category
FUEL COMBUSTION
Electric Utilities
Coal
OS
Gas
Internal Combustion
Industrial
Coat
Oil
Gas
Other
Internal Combustion
Other
Commercial/Institutional Coal
CommerciaVInstltutlonal Oil
CommerciaL'liKtitutional Gas
Misc. Fuel Con*. (Except Residential)
Residential Wood
Residential Other
INDUSTRIAL PROCESSES
Chemical & Allied Processing
Metals Processing
Petroleum & Belated Industries
Other Industrial Processes
Solvent Utilization
Storage & Transport
Waste Disposal & Recycling
TRANSPORTATION
On-Road Vehicles
Non-Road Sources
MISCELLANEOUS
TOTAL ALL SOURCES
1989
10,537
6,593
5,676
285
582
49
3,209
615
294
1,625
120
556
736
38
106
159
11
75
347
852
273
83
97
311
3
2
84
12,210
7,682
4,528
293
23,893
1990
10,895
6,663
5,642
221
565
235
3,035
585
265
1,182
131
874
1,196
40
97
200
34
46
780
892
168
97
153
378
1
3
91
11,893
7,089
4,804
369
24,049
1991
10,779
6,519
5,559
212
580
168
2,979
570
237
1,250
129
793
1,281
36
88
210
32
50
865
816
165
76
121
352
2
6
95
12,368
7,469
4,900
286
24,249
1992
10,928
6,504
5,579
170
579
175
3,071
574
244
1,301
126
825
1,353
38
93
225
28
53
916
857
163
81
148
361
3
5
96
12,556
7,622
4,934
255
24,596
1993
11,111
6,651
5,744
180
551
176
3,151
569
245
1,330
124
863
1,308
40
93
232
31
45
867
861
155
83
123
370
3
5
123
12,748
7,806
4,942
241
24,961
1994
11,015
6,565
5,636
163
591
175
3,147
602
24?
1,333
124
846
1,303
40
95
237
31
44
857
878
160
91
117
389
3
5
114
13,090
8,075
5,015
390
25,372
1995
10,827
6,384
5,579
96
562
148
3,144
597
247
1,324
123
854
1,298
38
103
231
30
49
847
873
158
98
110
399
3
6
99
12,954
7,826
5,128
267
24,921
1996
10,354
6,057
5,542
103
265
147
3,072
642
23 1
1,184
124
967
1,224
33
92
238
26
51
783
854
146
83
134
386
2
7
95
13,016
7,848
5,167
452
24,676
1997
10,403
6,191
5,609
129
299
154
3,019
636
223
1,168
119
948
1,193
34
94
243
27
43
752
884
149
88
138
404
2
7
96
13,126
7,875
5,251
411
24,824
1998
10,189
6,103
5,395
208
344
156
2,969
622
216
1,154
119
932
1,117
36
77
234
28
42
700
893
152
88
138
408
2
7
97
13,044
7,765
5,280
328
24,454
Note: Some columns may not sum to totals due to rounding.
122 DATA TABLES - APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-5. National Volatile Organic Compounds Emissions Estimates, 1989-1998 (thousand short tons)
Source Category
FUEL COMBUSTION
Electric Utilities
Coal
Oil
Gas
Internal Combustion
Industrial
Coal
Oil
Gas
Other
Internal Combustion
Other
Residential Wood
Other
INDUSTRIAL PROCESSES
Chemical & Allied Processing
Metals Processing
Petroleum & Related Industries
Other Industrial Processes
Solvent Utilization
Storage & Transport
Waste Disposal & Recycling
TRANSPORTATION
On-Road Vehicles
Non-Road Sources
MISCELLANEOUS
Other Combustion
Fires
Other
Other
TOTAL ALL SOURCES
1989
1,372
37
27
7
2
1
134
7
16
61
36
15
1,200
1,169
31
10,755
980
74
639
403
5,964
1,753
941
9,744
7,192
2,552
642
641
641
NA
1
22,513
1990
1,005
47
27
6
2
12
182
7
12
58
51
54
776
778
58
10,000
634
122
612
401
5,750
1,495
986
8,858
6,313
2,545
1,073
1,049
1,046
3
24
20,936
1991
1,075
44
27
5
2
10
196
6
11
60
51
68
835
776
59
10,178
710
123
640
391
5,782
1,532
999
9,080
6,499
2,581
769
743
740
3
26
21,102
1992
1,114
44
27
4
2
10
187
7
12
52
49
66
884
822
62
10,380
715
124
632
414
5,901
1,583
1,010
8,665
6,072
2,594
500
474
47?
3
26
20,659
1993
993
45
29
4
. 2
10
186
6
12
51
51
66
762
638
64
10,578
701
124
649
442
6,016
1,600
1,046
8,727
6,103
2,624
569
544
541
3
25
20,868
1994
989
45
29
4
2
10
196
8
12
63 '
50
64
748
684
63
10,738
691
126
647
438
6,162
1,629
1,046
9,074
6,401
2,672
734
707
704
3
27
21,535
1995
1,073
44
29
3
2
10
206
6
12
73
50
65
823
759
64
10,780
660
125
642
450
6,183
1,652
1,067
8,401
5,701
2,699
564
537
533
3
28
20,817
1996
1,036
49
28
3
8
10
166
7
8
49
40
62
821
759
62
8,591
388
72
488
428
5,506
1,286
423
8,155
5,490
2,664
954
891
887
3
63
18,736
1997
900
51
29
3
8
11
162
6
8
49
38
61
686
624
61
8,812
390
76
499
444
5,654
1,324
427
7,902
5,330
2,572
1,263
1,199
1,196
3
64
18,876
1998
893
54
29
5
9
11
161
6
8
49
38
60
678
620
58
8,452
396
75
496
450
5,278
1,324
433
7,786
5,325
2,461
785
721
717
3
65
17,917
Note: Some columns may not sum to totals due to rounding.
APPENDIX A
DATA TABLES
123
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-6. National PM10 Emissions Estimates, 1989-1998 (thousand short tons)
Source Category
FUEL COMBUSTION
Electric Utilities
Coal
Oil
Gas
Internal Combustion
Industrial
Coal
Oil
Gas
Other
Internal Combustion
Other
Residential Wood
Other
INDUSTRIAL PROCESSES
Chemical & Allied Processing
Metals Processing
Petroleum & Related Industries
Other Industrial Processes
Solvent Utilization
Storage & Transport
Waste Disposal & Recycling
TRANSPORTATION
On-Road Vehicles
Non-Road Sources
TOTAL ALL SOURCES
Table A-7. Miscellaneous and
Source Category
MISCELLANEOUS
Agriculture & Forestry
Other Combustion
Fires
Other
Cooling Towers
Fugitive Dust
Wind Erosion
Unpaved Roads
Paved Roads
Construction
Other
NAT. SOURCES (wind erosion)
TOTAL ALL SOURCES
Note
1989
1,382
271
255
12
1
3
243
70
48
44
78
3
869
817
52
1,276
63
211
58
591
2
101
251
844
367
477
3,502
Natural
1989
37,461
7,320
912
853
59
NA
29,229
0
11,798
5,769
11,269
392
12,101
49,562
: Some
1990
1,196
295
265
9
1
20
270
84
52
41
87
6
631
50?
130
1,306
77
214
55
583
4
102
271
825
336
489
3,327
1991
1,147
257
232
10
1
15
233
72
44
34
72
10
657
535
122
1,264
68
251
43
520
5
101
276
838
349
489
3,249
Paniculate Matter
1990
24,542
5,292
1,181
1,159
22
0
18,069
1
11,234
2,248
4,249
336
2,092
26,635
columns
1991
24,234
5,234
924
902
23
0
18,076
1
11,206
2,399
4,092
377
2,077
26,311
1992
1,183
257
234
7
0
16
243
74
45
40
74
11
683
558
124
1,269
71
250
43
506
5
117
278
833
343
490
3,286
Emissions
1992
23,959
5,017
770
747
23
0
18,171
1
10,918
2,423
4,460
369
2,227
26,186
1993
1,124
279
253
9
1
17
257
71
45
43
86
12
588
464
124
1,240
66
181
38
501
6
114
334
804
321
483
3,168
1994
1,113
273
246
8
1
17
270
70
44
43
74
38
570
446
125
1,219
76
184
38
495
6
106
313
800
320
480
3,133
1995
1,179
268
244
5
1
18
302
70
49
45
73
64
610
484
126
1,231
67
212
40
511
6
109
287
749
293
456
3,159
1996
1,174
287
264
5
1
18
255
77
46
43
77
16
632
503
129
985
63
164
32
327
6
90
304
739
282
457
2,898
1997
1,089
293
268
6
1
18
249
76
43
42
73
16
548
415
133
1,010
64
171
32
337
6
93
307
730
272
458
2,830
1998
1,091
302
273
9
1
19
245
74
42
42
74
15
544
411
133
1,016
65
171
32
339
6
94
310
718
257
461
2,825
Estimates, 1989-1998 (thousand short tons)
1993
24,329
4,575
801
777
23
0
18,954
1
1 1,430
2,462
4,651
409
509
24,838
may not sum to totals due to
1994
25,620
4,845
1,053
1,029
24
0
19,722
1
11,370
2,538
5,245
569
2,160
27,780
rounding.
1995
22,766
4,902
850
826
24
1
17,013
1
10,362
2,409
3,654
586
1,146
23,912
1996
24,836
4,905
1,254
1,235
19
2
18,675
r
12,059
2,390
3,578
646
5,307
30,143
1997
26,089
4,971
1,313
7,292
21
2
19,804
1
12,530
2,538
4,022
713
5,307
31,396
1998
26,609
4,970
1,018
997
21
2
20,619
1
12,668
2,618
4,545
788
5,307
31,916
124 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, A99S
Table A-8. National Sulfur Dioxide Emissions Estimates, 1989-1998 (thousand short tons)
Source Category
FUEL COMBUSTION
Electric Utilities
Coal
Oil
Gas
Internal Combustion
Industrial
Coal
Oil
Gas
Other
Internal Combustion
Other
Commercial/Institutional Coal
Commercial/Institutional Oil
Commercial/Institutional Gas
Misc. Fuel Comb. (Except Residential)
Residential Wood
Residential Other
INDUSTRIAL PROCESSES
Chemical & Allied Processing
Metals Processing
Petroleum & Related Industries
Other Industrial Processes
Solvent Utilization
Storage & Transport
Waste Disposal & Recycling
TRANSPORTATION
On-Road Vehicles
Non-Road Sources
MISCELLANEOUS
TOTAL ALL SOURCES
1989
19,924
16,215
15,404
779
1
30
3,086
1,840
812
346
82
6
624
169
274
2
1
11
167
2,010
440
695
429
405
1
5
36
1,349
570
779
11
23,293
1990
20,290
15,909
15,220
639
1
49
3,550
1,914
927
543
158
9
831
212
425 .
7
6
7
175
1,900
297
726
430
399
0
7
42
1,458
542
916
12
23,660
1991
19,796
15,784
15,087
652
1
45
3,256
1,805
779
516
142
14
755
184
376
7
6
7
176
1,721
280
612
378
396
0
10
44
1,513
570
944
11
23,041
1992
19,493
15,416
14,824
546
1
46
3,292
1,783
801
- 552
140
16
784
190
396
7
6
8
177
1,758
278
615
416
396
1
9
44
1,546
578
968
10
22,806
1993
19,245
15,189
14,527
612
1
49
3,284
1,763
809
' 555
140
17
772
193
381
8
6
6
178
1,723
269
603
383
392
1
5
71
1,489
517
972
10
22,466
1994
18,887
14,889
14,313
522
1
53
3,218
1,740
777
542
141
19
780
192
391
8
6
6
177
1,676
275
562
379
398
1
2
60
1,292
301
990
15
21,870
1995
16,230
12,080
11,603
413
9
55
3,357
1,728
912
548
147
23
793
200
397
8
5
7
176
1,637
286
530
369
403
1
2
47
1,304
304
999
10
19,181
1996
16,320
12,631
12,137
436
3
56
3,022
1,536
844
556
140
17
667
777
338
10
4
7
131
1,452
291
429
337
350
1
3
41
1,332
316
1,016
17
19,121
1997
16,732
13,090
12,542
488
1
59
2,964
1,521
801
563
134
.16
677
183
345
10
4
6
130
1,503
296
450
346
365
1
3
42
1,371
322
1,050
16
19,622
1998
16,722
13,217
12,426
730
2
60
2,895
1,485
773
558
133
16
609
194
275
10
4
6
121
1,503
299
444
345
370
1
3
42
1,410
326
1,084
12
19,647
Note: Some columns may not sum to totals due to rounding.
APPENDIX A
DATA TABLES 125
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-£. National Long-Term Air Quality Trends, 1979-1998
Year
1979-88
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1389-38
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
CO
2nd Max. 8-hr
ppm
(251 sites)
9.1
8.5
8.2
7.8
7.7
7.7
7.0
7.0
6.6
6.5
(383 sites)
6.2
5.8
5.6
5.2
4.9
5.1
4.5
4.2
3.9
3.8
Pb
Max. Qtr.
pg/m3
(184 sites)
0.97
0.77
0.61
0.55
0.41
0.37
0.24
0.15
0.12
0.11
(189 sites)
0.09
0.09
0.07
0.06
0.05
0.05
0.04
0.04
0.04
0.04
NO2
Arith. Mean
ppm
(127 sites)
0.024
0.024
0.023
0.022
0.022
0.023
0.022
0.022
0.022
0.022
(225 sites)
0.021
0.020
0.020
0.019
0.019
0.020
0.019
0.019
0.018
0.018
Ozone
2nd Max. 1-hr
ppm
(401 sites)
0.133
0.135
0.125
0.123
0.136
0.123
0.122
0.118
0.124
0.135
(661 sites)
0.114
0.112
0.113
0.105
0.108
0.107
0.112
0.106
0.105
0.110
PM10
Wtd. Arith. Mean
pg/ms
—
—
—
—
— --
—
—
—
—
—
—
(934 sites)
31.7
• 29.4
29.1
26.8
26.0
26.0
24.9
23.9
23.8
23.7
S02
Arith. Mean
ppm
(389 sites)
0.0113
0.0105
0.0102
0.0093
0.0090
0.0092
0.0086
0.0084
0.0082
0.0083
(483 sites)
0.0087
0.0082
0.0079
0.0074
0.0072
0.0070
0.0057
0.0056
0.0054
0.0053
126 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, i99S
Table A-10. National Air Quality Trends by Monitoring Location, 1989-1998
Statistic # of Sites
Units
Location
1989
1990
1991
1992
1993
1994
1995
1996
1997 1998
Carbon Monoxide
2nd Max. 8-hr.
2nd Max. 8-hr.
2nd Max. 8-hr.
12
148
200
ppm
ppm
ppm
Rural
Suburban
Urban
2.8
6.0
6.6
2.8
5.6
6.1
2.8
5.3
6.0
2.5
5.0
5.5
2.1
4.9
5.0
2.3
5.0
5.3
2.4
4.3
4.8
1.9
4.1
4.5
1.8
3.9
4.1
1.8
3.8
3.9
Lead
Max. Qtr.
Max. Qtr.
Max. Qtr.
Nitrogen Dioxide
Arith. Mean
Arith. Mean
Arith. Mean
IQzone
2nd Max. 1-hr.
2nd Max. 1-hr.
2nd Max. 1-hr.
5
98
82
39
104
80
222
304
117
ug/m3
ug/m3
ug/m3
ppm
ppm
ppm
ppm
ppm
ppm
Rural
Suburban
Urban
Rural
Suburban
Urban
Rural
Suburban
Urban
0.06
0.08
0.09
0.009
0.022
0.026
0.108
0.118
0.114
0.06
0.07
0.11
0.009
0.021
0.025
0.108
0.116
0.110
0.07
0.06
0.07
0.009
0.020
0.024
0.106
0.118
0.111
0.07
0.05
0.07
0.008
0.020
0.024
0.101
0.109
0.105
0.06
0.05
0.06
0.008
0.020
0.024
0.103
0.111
0.105
0.04
0.04
0.06
0.008
0.020
0^025
0.102
0.111
0.106
0.04
0.04
0.05
0.008
0.020
0.024
0.107
0.116
0.110
0.03
0.03
0.05
0.008
0.019
0.023
0.103
0.108
0.106
0.03
0.03
0.05
0.007
0.018
0.023
0.101
0.109
0.102
0.03
0.03
0.04
0.007
0.018
0.023
0.107
0.114
0.104
fMw .:
Wtd. Arith. Mean
Wtd. Arith. Mean
Wtd. Arith. Mean
.Sulfur Dioxide
Arith. Mean
Arith. Mean
Arith. Mean
138
355
418
122
213
137
ug/m3
ug/m3
|jg/m3
ppm
ppm
ppm
Rural
Suburban
Urban
Rural
Suburban
Urban
25.6
32.9
33.0
0.0071
0.0091
0.0099
24.3
30.6
30.4
0.0068
0.0086
0.0091
23.6
30.2
30.5
0.0066
0.0083
0.0087
21.8
27.8
27.9
0.0063
0.0077
0.0080
20.6
27.1
27.2
0.0064
0.0075
0.0077
20.6
27.0
27.3
0.0060
0.0072
0.0076
19.3
26.2
26.0
0.0053
0.0057
0.0060
19.3
24.9
25.1
0.0051
0.0058
0.0059
18.9
24.8
24.9
0.0048
0.0057
0.0057
18.9
24.6
25.0
0.0048
0.0056
0.0055
APPENDIX A • DATA TABLES 127
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-11. National Air Quality Trends Statistics by EPA Region, 1989-1998
Region 1
CO
Pb
NO,
o,
o,
PM,0
so,
Region 2
CO
Pb
NO,
o,
0,
PM«,
SO,
Region 3
CO
Pb
NO,
o,
o,
PM10
SO,
Region 4
CO
Pb
NO2
O3
O3
PM10
SO2
Region 5
CO
Pb
NOj
o,
O3
PM,0
SO,
Statistic # of
2nd Max. 8-hr.
Max. Qtr.
Arith. Mean
2nd Max. 1-hr.
4th Max. 8-hr.
Wtd. Arith. Mean
Arith. Mean
2nd Max. 8-hr.
Max. Qtr.
Arith. Mean
2nd Max. 1-hr.
4th Max. 8-hr.
Wtd. Arith. Mean
Arith. Mean
2nd Max. 8-hr.
Max. Qtr.
Arith. Mean
2nd Max. 1-hr.
4th Max. 8-hr.
Wtd. Arith. Mean
Arith. Mean
2nd Max. 8-hr.
Max. Qtr.
Arith. Mean
2nd Max. 1-hr.
4th Max. 8-hr.
Wtd. Arith. Mean
Arith. Mean
2nd Max. 8-hr.
Max. Qtr.
Arith. Mean
2nd Max. 1-hr.
4th Max. 8-hr.
Wtd. Arith. Mean
Arith. Mean
Sites
17
—
14
38
38
72
50
27
4
12
34
34
68
41
40
25
35
71
71
67
71
55
26
25
115
115 '
130
67
43
47
14
126
126
161
120
Units
ppm
pg/m3
ppm
ppm
ppm
pg/m3
ppm
ppm
pg/m3
ppm
ppm
ppm
pg/m3
ppm
ppm
pg/m3
ppm
ppm
ppm
pg/m3
ppm
ppm
pg/m3
ppm
ppm
ppm
pg/m3
ppm
ppm
pg/m3
ppm
ppm
ppm
pg/m3
ppm
1989
5.8
—
0.023
0.122
0.092
24.4
0.0088
6.4
0.09
0.031
0.116
0.093
28.8
0.0105
5.5
0.09
0.022
0.109
0.087
32.2
0.0134
6.0
0.07
0.015
0.100
0.078
30.0
0.0062
5.7
0.11
0.023
0.108
0.086
33.4
0.0098
1990
6.1
—
0.022
0.119
0.091
22.8
0.0080
5.7
0.10
0.030
0.122
0.096
26.6
0.0094
5.1
0.07
0.021
0.110
0.088
29.7
0.0126
5.3
0.06
0.014
0.105
0.083
30.0
0.0061
5.1
0.16
0.021
0.102
0.082
30.9
0.0093
1991
5.6
—
0.022
0.130
0.099
23.5
0.0077
5.7
0.07
0.029
0.124
0.101
27.0
0.0096
4.6
0.07
0.021
0.118
0.096
30.6
0.0120
5.0
0.05
0.014
0.097
0.075
28.6
0.0058
4.8
0.09
0.021
0.112
0.089
30.2
0.0091
1992
5.7
—
0.021
0.110
0.086
20.7
0.0073
5.1
0.06
0.028
0.109
0.085
24.2
0.0089
4.3
0.06
0.021
0.102
0.082
26.5
0.0110
5.0
0.05
0.014
0.095
0.077
26.5
0.0056
4.4
0.09
0.022
0.098
0.079
27.8
0.0080
1993
4.8
- —
0.022
0.119
0.089
20.2
0.0069
4.6
0.07
0.028
0.111
0.088
24.3
0.0081
4.2
0.05
0.021
0.115
0.092
26.8
0.0111
5.0
0.04
0.014
0.104
0.081
25.8
0.0056
4.4
0.08
0.022
0.097
0.077
26.4
0.0081
1994
6.0
—
0.022
0.115
0.087
20.7
0.0067
5.3
0.07
0.029
0.105
0.085
24.8
0.0083
4.7
0.05
0.022
0.111
0.088
27.7
0.0112
4.7
0.04
0.014
0.099
0.080
25.5
0.0052
5.3
0.08
0.024
0.105
0.084
28.1
0.0076
1995
5.4
—
0.020
0.118
0.091
18.7
0.0053
4.6
0.06
0.027
0.115
0.095
22.1
0.0064
4.0
0.04
0.020
0.116
0.094
26.6
0.0084
4.3
0.04
0.014
0.104
0.082
25.2
0.0044
4.1
0.06
0.023
0.111
0.090
27.3
0.0061
1996
4.8
—
0.020
0.103
0.081
19.3
0.0052
4.1
0.06
0.028
0.104
0.083
22.9
0.0064
3.7
0.04
0.021
0.105
0.085
25.2
0.0085
3.8
0.03
0.014
0.102
0.081
23.9
0.0046
3.3
0.06
0.023
0.103
0.085
24.7
0.0061
1997
4.2
—
0.020
0.117
0.090
19.7
0.0050
3.6
0.06
0.027
0.111
0.093
23.5
0.0058
3.4
0.03
0.020
0.116
0.093
25.3
0.0089
4.0
0.03
0.014
0.103
0.082
23.9
0.0045
3.1
0.06
0.022
0.102
0.083
24.8
0.0059
1998
3.7
—
0.020
0.107
0.084
19.8
0.0050
3.3
0.06
0.027
0.109
0.088
23.2
0.0057
3.1
0.03
0.020
0.115
0.095
25.1
0.0086
3.7
0.03
0.014
0.112
0.091
24.5
0.0047
3.2
0.05
0.023
0.105
0.085
26.2
0.0059
128 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-11. National Air Quality Trends Statistics by EPA Region, 1989-1998 (continued)
Statistic # of Sites
Units
1989
1990
1991
1992
1993
1994
1995
1996
1997 1998
^Region 6 ,
CO 2nd Max. 8-hr.
Pb Max. Qtr.
NO2 Arith. Mean
O3 2nd Max. 1-hr.
O3 4th Max. 8-hr.
PM10 , Wtd. Arith. Mean
SO2 Arith. Mean
31
25
22
69
69
94
32
ppm
|jg/m3
ppm
ppm
ppm
(jg/m3
ppm
6.2
0.12
0.016
0.119
0.085
28.7
0.0064
6.2
0.10
0.015
0.122
0.087
25.7
0.0063
5.4
0.10
0.015
0.113
0.080
24.3
0.0060
5.4
0.08
0.016
0.109
0.079
24.4
0.0063
5.3
0.07
0.015
0.111
0.080
23.6
0.0053
4.7
0.05
0.017
0.109
0.082
23.8
0.0046
4.4
0.06
0.016
0.122
0.091
24.7
0.0046
4.9
0.07
0.016
0.110
0.082
23.7
0.0047
4.3 4.0
0.04 0.04
0.016 0.015
0.114 0.116
0.083 0.087
22.3 23.3
0.0043 0.0042
|, . Region 7
CO 2nd Max. 8-hr.
Pb Max. Qtr.
NO2 Arith. Mean
O3 2nd Max. 1-hr.
O3 4th Max. 8-hr.
PM,0 Wtd. Arith. Mean
SO2 Arith. Mean
22
19
12
29
29
49
30
ppm
ug/m3
ppm
ppm
ppm
[jg/m3
ppm
5.3
0.05
0.016
0.093
0.074
32.1
0.0083
4.9
0.03
0.015
0.090
0.070
29.7
0.0076
5.1
0.03
0.015
0.092
0.075
28.9
0.0072
4.4
0.02
0.016
0.091
0.074
28.2
0.0064
4.3
0.02
0.015
0.088
0.066
27.0
0.0063
4.2
0.01
0.016
0.098
0.078
27.9
0.0064
4.0
0.01
0.016
0.103
0.082
27.1
0.0053
4.1
0.02
0.016
0.094
0.075
27.5
0.0050
3.7 4.2
0.04 0.04
0.016 0.016
0.094 0.100
0.076 0.078
25.5 25.4
0.0046 0.0044
fr Region 8
CO 2nd Max. 8-hr.
Pb Max. Qtr.
NO2 Arith. Mean
O3 2nd Max. 1-hr.
O3 4th Max. 8-hr.
PM,0 Wtd. Arith. Mean
SO2 Arith. Mean
17
7
14
17
17
106
27
ppm
|jg/m3
ppm
ppm
ppm
pg/m3
ppm
7.2
0.06
0.015
0.095
0.073
27.2
0.0063
6.6
0.06
0.014
0.089
0.068
24.1
0.0061
6.7
0.06
0.014
0.086
0.069
25.2
0.0058
6.7
0.05
0.014
0.083
0.065
23.8
0.0064
5.8
0.06
0.014
0.081
0.064
22.7
0.0062
5.2
0.04
0.015
0.085
0.067
22.2
0.0055
5.1
0.04
0.014
0.084
0.067
19.3
0.0049
. 4.8
0.03
0.014
0.088
0.069
19.6
0.0041
4.7 3.8
0.03 0.03
0.014 0.014
0.083 0.093
0.066 0.075
18.8 18.8
0.0034 0.0031
Up Region 9
CO 2nd Max. 8-hr.
Pb Max. Qtr.
NO2 Arith. Mean
O3 2nd Max. 1-hr.
O3 4th Max. 8-hr.
PM10 Wtd. Arith. Mean
SO2 Arith. Mean
95
31
77
149
149
119
35
ppm
[jg/rn3
ppm
ppm
ppm
ug/m3
ppm
6.7
0.07
0.023
0.137
0.095
41.8
0.0030
6.3
0.07
0.022
0.127
0.090
38.3
0.0026
6.1
0.06
0.022
0.126
0.090
37.5
0.0025
5.3
0.03
0.021
0.125
0.090
32.7
0.0025
4.9
0.03
0.020
0.120
0.088
31.6
0.0023
5.2
0.03
0.021
0.117
0.086
30.6
0.0022
4.6
0.03
0.020
0.119
0.087
30.5
0.0025
4.5
0.02
0.019
0.115
0.087
28.7
0.0024
4.1 4.1.
0.02 0.02
0.018 0.018
0.102 0.112
0.078 0.084
29.1 26.8
0.0022 0.0021
| Region 10
CO 2nd Max. 8-hr.
Pb Max. Qtr.
NO2 Arith. Mean
O3 2nd Max. 1-hr.
O3 4th Max. 8-hr.
PM10 Wtd. Arith. Mean
SO2 Arith. Mean
16
5
—
13
13
63
9
ppm
ug/m3
ppm
ppm
ppm
ug/m3
ppm
8.6
0.06
—
0.083
0.061
34.3
0.0066
7,7
0.06
—
0.099
0.072
31.5
0.0071
8.0
0.06
—
0.086
0.064
32.5
0.0070
7.5
0.04
—
0.087
0.069
30.7
0.0073
6.4
0.05
• —
0.081
0.058
30.3
0.0066
6.1
0.05
—
0.088
0.063
26.7
0.0066
5.9
0.05
—
0.086
0.063
23.2
0.0059
5.9
0.04
—
0.097
0.076
23.2
0.0051
5.5 5.0
0.05 0.06
— —
0.076 0.097
0.058 0.068
23.5 21.1
0.0047 0.0047
APPENDIX A • DATA TABLES 129
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998
State
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AL
AK
AK
AK
AK
AK
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AR
AR
AR
AR
AR
AR
AR
AR
AR
AR
AR
AR
AR
AR
AR
AR
County
CLAY CO
COLBERT CO
DE KALB CO
ELMORE CO
ESCAMBIA CO
ETOWAH CO
FRANKLIN CO
GENEVA CO
HOUSTON CO
JACKSON CO
JEFFERSON CO
LAWRENCE CO
LIMESTONE CO
MADISON CO
MARENGO CO
MOBILE CO
MONTGOMERY CO
PIKE CO
RUSSELL CO
SHELBY CO
SUMTER CO
TALLADEGA CO
TUSCALOOSA CO
WALKER CO
ANCHORAGE BOROUGH
FAIRBANKS N. STAR BOR.
JUNEAU BOROUGH
MATANUSKA-SUSITNA BOR.
YUKON-KOYUKUK CA
COCHISE CO
COCONINO CO
GRAHAM CO
MARICOPA CO
PIMA CO
FINAL CO
SANTA CRUZ CO
YAVAPAI CO
YUMA CO
ARKANSAS CO
ASHLEY CO
CRAIGHEAD CO
CRITTENDEN CO
GARLAND CO
JEFFERSON CO
MARION CO
MILLER CO
MONTGOMERY CO
NEWTON CO
OUACHITA CO
PHILLIPS CO
POPE CO
PULASKI CO
SEBASTIAN CO
UNION CO
1990
Population
13,252
51,666
54,651
49,210
35,518
99,840
27,814
23,647
81,331
47,796
651,525
31,513
54,135
238,912
23,084
378,643
209,085
27,595
46,860
99,358
16,174
74,107
150,522
67,670
226,338
77,720
26,751
39,683
8,478
97,624
96,591
26,554
2,122,101
666,880
116,379
29,676
107,714
106,895
21,653
24,319
68,956
49,939
73,397
85,487
12,001
38,467
7,841
7,666
30,574
28,838
45,883
349,660
99,590
46,719
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (pg/m3) (ppm) (ppm)
0.117
0.116
0.092
4.4 . . 0.127
0.102
3.3 . . 0.118
0.114
0.121
0.63
0.0090 0.137
0.083
8.4 ..
10.2
0.057
0.077
0.076
8.1 . 0.0350 0.113
4.0 . 0.0165 0.094
0.101
0.101
0.092
0.084
4.8 . 0.0105 0.098
O3 (8-hr)
4th Max
(ppm)
0.094
.
0.091
0.077
0.101
0.085
0.092
0.098
0.092
0.107
0.068
0.054
0.067
0.072
0.090
0.077
0.089
0.086
0.071
0.078
0.082
PM10
2nd Max
(M9/m3)
45
58
59
65
46
63
'109
43
57
46
153
57
56
56
52
53
54
50
103
47
41
87
89
68
208
78
171
30
73
52
54
57
47
35
53
55
43
47
98
49
57 -
S02
24-hr
(ppm)
0.019
0.025
0.032
0.011
0.073
0.010
0.018
0.004
0.027
0.015
0.006
0.028
130 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
AR
AR
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
County
WASHINGTON CO
WHITE CO
ALAMEDA CO
AMADOR CO
BUTTE CO
CALAVERAS CO
COLUSA CO
CONTRA COSTA CO
DEL NORTE CO
EL DORADO CO
FRESNO CO
GLENN CO
HUMBOLDT CO
IMPERIAL CO
INYO CO
KERN CO
KINGS CO
LAKE CO
LOS ANGELES CO
MADERA CO
MARIN CO
MARIPOSA CO
MENDOCINO CO
MERCED CO
MONO CO
MONTEREY CO
NAPA CO
NEVADA CO
ORANGE CO
PLACER CO
PLUMAS CO
RIVERSIDE CO
SACRAMENTO CO
SAN BENITO CO
SAN BERNARDINO CO
SAN DIEGO CO
SAN FRANCISCO CO
SAN JOAQUIN CO
SAN LUIS OBISPO CO
SAN MATED CO
SANTA BARBARA CO
SANTA CLARA CO
SANTA CRUZ CO
SHASTA CO
SIERRA CO
SISKIYOU CO
SOLANO CO
SONOMA CO
STANISLAUS CO
SUTTER CO
TEHAMA CO
TRINITY CO
TULARE CO
TUOLUMNE CO
1990
Population
113,409
54,676
1,279,182
30,039
182,120
31,998
16,275
803,732
23,460
125,995
667,490
24,798
119,118
109,303
18,281
543,477
101,469
50,631
8,863,164
88,090
230,096
14,302
80,345
178,403
9,956
355,660
110,765
78,510
2,410,556
172,796
19,739
1,170,413
1,041,219
36,697
1;41 8,380
2,498,016
723,959
480,628
217,162
649,623
369,608
1 ,497,577
229,734
147,036
3,318
43,531
340,421
388,222
370,522
64,415
49,625
13,063
311,921
48,456
CO
8-hr
(ppm)
4.2
1.3
3.8
0.8
3.1
4.2
6.9
13.3
3.4
11.5
3.2
3.2
2.9
1.9
3.5
6.6
2.2
4.6
6.1
4.5
4.7
3.5
5.3
2.0
3.9
3.9
6.3
0.8
4.9
3.0
5.4
3.9
3.6
5.4
Pb
QMax
(ug/m3)
0.00
0.00
0.01
0.00
0.02
0.00
0.05
0.00
0.05
0.01
0.04
0.01
0.01
0.00
0.00
0.01
0.00
NO2
AM
(ppm)
0.0203
0.0133
0.0163
0.0099
0.0199
0.0114
0.0238
0.0142
0.0434
0.0112
0.0172
0.0096
0.0114
0.0095
0.0124
0.0339
0.0156
0.0221
0.0205
0.0356
0.0229
0.0197
0.0230
0.0113
0.0176
0.0212
0.0248
0.0044
0.0135
0.0146
0.0181
0.0129
0.0166
03(1-hr)
2nd Max
(ppm)
0.139
0.129
0.103
0.124
0.096
0.130
0.144
0.167
0.095
0.137
0.087
0.158
0.136
0.070
0.200
0.127
0.073
0.111
0.072
0.140
0.078
0.085
0.101
0.112
0.158
0.145
0.081
0.193
0.154
0.113
0.241
0.135
0.051
0.115
0.114
0.065
0.116
0.142
0.092
0.140
0.077
0.129
0.100
0.145
0.104
0.120
0.144
0.116
03(8-hr)
4th Max
(ppm)
0.096
0.107
0.078
0.105
0.078
0.088
0.115
0.122
0.074
0.098
0.082
0.124
0.104
0.055
0.140
0.094
0.047
0.097
0.060
0.112
0.067
0.069
0.095
0.093
0.099
0.069
0.135
0.113
0.088
0.183
0.114
0.042
0.089
•0.098
0.047
0.086
0:094
0.068
0.105
0.066
0.096
0.086
0.107
0.088
0.098
0.109
0.100
PM10
2nd Max
(ug/m3)
44
51
54
60
35
75
64
33
55
126
73
41
231
814
131
126
22
78
46
40
41
46
50
33
112
65
57
65
114
99
36
102
88
49
102
67
51
55
60
67
54
55
63
49
40
110 •
55
39
136
S02
24-hr
(ppm)
0.014
0.017
0.012
0.005
0.009
0.015
0.009
0.016
0.006
0.030
0.004
0.003
0.005
APPENDIX A • DATA TABLES 131
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
CA
CA
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CT
CT
CT
CT
CT
CT
CT
CT
DE
DE
DE
DC
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
County
VENTURA CO
YOLO CO
ADAMS CO
ALAMOSA CO
ARAPAHOE CO
ARCHULETA CO
BOULDER CO
DELTA CO
DENVER CO
DOUGLAS CO
EL PASO CO
FREMONT CO
GARFIELD CO
GUNNISON CO
JEFFERSON CO
LAKE CO
LA PLATA CO
LARIMER CO
MESA CO
MONTEZUMA CO
MONTROSE CO
PITKIN CO
PROWERS CO
PUEBLO CO
ROUTT CO
SAN MIGUEL CO
SUMMIT CO
TELLER CO
WELD CO
FAIRFIELD CO
HARTFORD CO
LITCHFIELD CO
MIDDLESEX CO
NEW HAVEN CO
NEW LONDON CO
TOLLAND CO
WINDHAM CO
KENT CO
NEW CASTLE CO
SUSSEX CO
WASHINGTON
ALACHUA CO
BAY CO
BREVARD CO
BROWARD CO
COLLIER CO
DADE CO
DUVAL CO
ESCAMBIA CO
GULF CO
HAMILTON CO
HILLSBOROUGH CO
LAKE CO
LEE CO
CO
1990 8-hr
Population (ppm)
669,016 2.9
141,092 1.1
265,038 3.5
13,617
391,511
5,345
225,339 4.8
20,980
467,610 5.2
60,391
397,014 3.8
32,273
29,974
10,273
438,430 3.6
6,007
32,284
186,136 4.1
93,145 5.3
18,672
24,423
12,661
13,347
123,051
14,088
3,653
12,881
12,468
131,821 4.4
827,645 3.8
851,783 7.1
174,092
143,196
804,219 2.7
254,957
128,699
102,525
110,993
441,946 3.1
113,229
606,900 4.6
181,596
126,994
398,978
1,255,488 3.5
152,099
1,937,094 3.4
672,971 3.1
262,798
11,504
10,930
834,054 4.1
152,104
335,113
Pb NO2
QMax AM
(ug/m3) (ppm)
0.00 0.0189
0.0107
0.11 0.0229
0.03 0.0353
0.01 0.0204
0.0101
0.03
0.0183
0.0198
0.02 0.0269
0.0163
0.02 0.0265
0.03 0.0095
0.0151
0.02 0.0150
0.51 0.0111
03(1-hr) 03(8-hr)
2nd Max 4th Max
(ppm) (ppm)
0.144
0.111
0.104
0.113
0.111
0.107
0.112
0.074
0.118
0.092
0.074
0.102
0.134
0.110
0.118
0.118
0.130
0.116
0.132
0.131
0.126
0.123
0.116
0.105
0.098
0.105
0.112
0.103
0.128
0.131
0.109
0.113
0.087
0.083
0.084
0.089
0.085
0.081
0.062
0.095
0.080
0.068
0.075
0.097
0.082
0.097
0.089
0.097
0.083
0.098
0.102
0.098
0.102
0.102
0.093
0.085
0.079
0.087
0.101
0.102
0.097
0.092
PM10
2nd Max
(ug/m3)
52
79
107
90
71
47
68
81
48
72
41
67
149
50
77
33
51
79
72
100
52
87
72
77
124
40
50
66
44
71
42
36
76
57
40
53
44
53 .
42
62
65
51
66
41
105
63
37
S02
24-hr
(ppm)
0.011
0.013
0.023
0.011
0.025
0.019
0.031
0.018
0.016
0.044
0.020
0.017
0.004
0.037
0.024
0.021
0.036
132 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
FL
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
GA
HI
HI
HI
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
ID
County
LEON CO
MANATEE CO
MARION CO
NASSAU CO
ORANGE CO
OSCEOLA CO
PALM BEACH CO
PASCO CO
PINELLAS CO
POLK CO
PUTNAM CO
ST LUCIE CO
SARASOTA CO
SEMINOLE CO
VOLUSIA CO
BALDWIN CO
BARTOW CO
BIBB CO
CHATHAM CO
CHATTOOGA CO
DAWSON CO
DE KALB CO
DOUGHERTY CO
DOUGLAS CO
FANNIN CO
FAYETTE CO
FLOYD CO
FULTON CO
GLYNN CO
GWINNETT CO
MUSCOGEE CO
PAULDING CO
RICHMOND CO
ROCKDALE CO
SPALDING CO
SUMTER CO
WALKER CO
WASHINGTON CO
HONOLULU CO
KAUAI CO
MAUI CO
ADA CO
BANNOCK CO
ELAINE CO
BONNER CO
BONNEVILLE CO
BUTTE CO
CANYON CO
CARIBOU CO
KOOTENAI CO
LEMHI CO
LEWIS CO
MADISON CO
MINIDOKA CO
1990
Population
192,493
211,707
194,833
43,941
677,491
107,728
863,518
281,131
851 ,659
405,382
65,070
150,171
277,776
287,529
370,712
39,530
55,911
149,967
216,935
22,242
9,429
545,837
96,311
71,120
15,992
62,415
81,251
648,951
62,496
352,910
179,278
41,611
189,719
54,091
54,457
30,228
58,340
19,112
836,231
51,177
100,374
205,775
66,026
13,552
26,622
72,207
2,918
90,076
6,963
69,795
6,899
3,516
23,674
19,361
CO Pb NO2
8-hr QMax AM
(ppm) (ug/m3) (ppm)
3.5 . 0.0110
3.0 0.00 0.0120
3.0 0.01 0.0115
5.6 . .
4.1 0.01
3.1 . 0.0241
0.58
0.0060
0.0077
2.3 . 0.0044
3.9 . 0.0202
03(1-hr)
2nd Max
(ppm)
0.090
0.115
0.097
0.117
0.123
0.105
0.103
0.108
0.106
0.095
. 0.122
0.101
0.096
0.137
0.097
0.109
0.142
0.133
0.100
0.141
0.157
0.109
0.139
0.113
0.138
0.119
0.134
0.095
0.056
0.070
03(8-hr)
4th Max
(ppm)
0.079
0.089
0.083
0.096
0.091
0.081
0.091
0.091
0.088
0.079
0.091
0.089
0.082
0.106
0.075
0.096
0.112
0.110
0.081 .
0.111
0.126
0.082
0.111
0.091
0.104
0.099
0.113
0.081
0.049
0.065
PM10
2nd Max
(ug/m3)
63
38
49
55
52
47
91
41
35
82
47
48
59
79
62
58
66
56
49
71
119
50
60
54
54
83
39
30
128
62
105
66
67
98
69
101
85
102
61
94
78
S02
24-hr
(ppm)
0.019
0.022
0.007
0.004
0.048
0.027
0.012
0.019
0.015
0.014
0.019
0.027
0.006
0.052
0.016
0.019
0.011
0.009
0.034
0.018
APPENDIX A
DATA TABLES
133
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
ID
ID
ID
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
County
NEZ PERCE CO
SHOSHONE CO
TWIN FALLS CO
ADAMS CO
CHAMPAIGN CO
COOK CO
DU PAGE CO
EFFINGHAM CO
HAMILTON CO
JACKSON CO
JERSEY CO
KANE CO
LAKE CO
LA SALLE CO
MC HENRY CO
MACON CO
MACOUPIN CO
MADISON CO
PEORIA CO
RANDOLPH CO
ROCK ISLAND CO
ST CLAIR CO
SANGAMON CO
TAZEWELL CO
WABASH CO
WILL CO
WINNEBAGO CO
ALLEN CO
CLARK CO
DAVIESS CO
DEARBORN CO
DE KALB CO
DELAWARE CO
DUBOIS CO
ELKHART CO
FLOYD CO
FOUNTAIN CO
GIBSON CO
HAMILTON CO
HANCOCK CO
HENDRICKS CO
JASPER CO
JEFFERSON CO
JOHNSON CO
LAKE CO
LA PORTE CO
MADISON CO
MARION CO
MORGAN CO
PERRY CO
PIKE CO
PORTER CO
POSEY CO
ST JOSEPH CO
1990
Population
33,754
13,931
53,580
66,090
173,025
5,105,067
781,666
31,704
8,499
61,067
20,539
317,471
516,418
106,913
183,241
117,206
47,679
249,238
182,827
34,583
148,723
262,852
178,386
123,692
13,111
357,313
252,913
300,836
87,777
27,533
38,835
35,324
119,659
36,616
156,198
64,404
17,808
31,913
108,936
45,527
75,717
24,960
29,797
88,109
475,594
107,066
130,669
797,159
55,920
19,107
12,509
128,932
25,968
247,052
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (M9/m3) (ppm) (ppm)
4.8 ..
0.15
0.095
0.105
5.0 0.10 0.0322 0.109
0.03 . 0.097
0.093
0.089
0.122
0.092
0.107
0.092
0.02 . 0.094
0.02 . 0.109
2.9 2.59 . 0.118
5.8 0.02 . 0.086
0.099
0.01 . 0.086
0.10 0.0182 0.101
1.9 . . 0.093
0.8 0.01 0.0087 0.095
3.6 0.04 . 0.085
3.0 . . 0.105
0.140
0.90
0.106
0.131
0.125
0.119
3.8 . . . •
0.101
4.5 0.12 0.0189 0.113
0.02 . 0.121
0.117
2.8 0.08 0.0189 0.115
0.102
0.114
0.121
0.107
0.0122 0.117
O3(8-hr)
4th Max
(ppm)
0.073
0.083
0.086
0.068
0.083
0.075
0.091
0.074
0.088
0.078
0.078
0.079
0.088
0.076
0.082
0.072
0.078
0.078
0.081
0.073
0.089
0.104
0.082
0.100
0.100
0.094
0.090
0.087
0.093
0.097
0.095
0.090
0.090
0.092
0.095
PM10
2nd Max
(M9/m3)
76
120
46
46
52
102
60
46
69
134
69
45
116
53
58
84
65
55
49
53
58
54
66
51
44
136
39
58
84
66
46
S02
24-hr
(ppm)
0.022
0.019
0.051
0.022
0.020
0.011
0.087
0.045
0.048
0.008
0.069
0.061
0.037
0.033
0.024
0.041
0.036
0.033
0.043
0.056
0.014
0.015
0.027
0.055
0.016
0.024
0.029
0.029
0.026
134 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
IN
IN
IN
IN
IN
IN
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
IA
KS
KS
KS
KS
KS
KS
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
KY
County
SPENCER CO
SULLIVAN CO
VANDERBURGH CO
VIGO CO
WARRICK CO
WAYNE CO
BLACK HAWK CO
CERRO GORDO CO
CLINTON CO
DELAWARE CO
HARRISON CO
LEE CO
LINN CO
MUSCATINE CO
PALO ALTO CO
POLK CO
POTTAWATTAMIE CO
SCOTT CO
STORY CO
VAN BUREN CO
WARREN CO
WOODBURY CO
FORD CO
LINN CO
SEDGWICK CO
SHAWN EE CO
SHERMAN CO
WYANDOTTE CO
BELL CO
BOONE CO
BOYD CO
BULLITT CO
CAMPBELL CO
CARTER CO
CHRISTIAN CO
DAVIESS CO
EDMONSON CO
FAYETTE CO
FLOYD CO
GRAVES CO
GREENUP CO
HANCOCK CO
HARDIN CO
HARLAN CO
HENDERSON CO
JEFFERSON CO
JESSAMINE CO
KENTON CO
LAWRENCE CO
LIVINGSTON CO
MC CRACKEN CO
MC LEAN CO
MADISON CO
MARSHALL CO
1990
Population
19,490
18,993
165,058
106,107
44,920
71,951
123,798
46,733
51 ,040
18,035
14,730
38,687
168,767
39,907
10,669
327,140
82,628
150,979
74,252
7,676
36,033
98,276
27,463
8,254
403,662
160,976
6,926
161,993
31,506
57,589
51,150
47,567
83,866
24,340
68,941
87,189
10,357
225,366
43,586
33,550
36,742
7,864
89,240
36,574
43,044
664,937
30,508
142,031
13,998
9,062
62,879
9,628
57,508
27,205
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (ug/m3) (ppm) (ppm)
4.0 . . 0.117
0.02 . 0.099
0.116
0.093
2.5 . . 0.078
0.081
10.4 . . 0.065
0.01
0.097
0.083
0.084
0.083
1.0 . . 0.104
5.5 0.01 . 0.100
4.0 . . 0.113
3.9 . . 0.102
0.110
7.2 . . 0.090
0.0123 0.108
0.0180 0.113
0.118
0.111
1.0 . 0.0125 0.110
0.112
2.9 . 0.0109 0.106
0.105
0.133
0.113
0.100
2.1 . 0.0176 0.111
5.5 . 0.0233 0.121
0.105
2.6 . 0.0179 0.121
0.088
0.131
2.4 . 0.0123 0.109
0.110
03(8-hr)
4th Max
(ppm)
0.094
0.084
0.096
0.079
0.066
0.068
0.056
0.077
0.070
0.071
. 0.070
0.080
0.083
0.087
0.087
0.084
0.096
0.089
0.096
0.086
0.086
0.097
0.089
0.086
0.099
0.095
0.083
0.084
0.097
0.089
0.091
0.093
0.090
0.085
PM10
2nd Max
(ug/m3)
53
52
54
120
72
52
76
60
68
121
67
52
75
67
66
69
51
94
46
57
64
39
42
41
67
59
i
54
49
56
55
51
80
S02
24-hr
(ppm)
0.023 '
0.026
0.049
0.032
0.071
0.037
0.087
0.024
0.047
0.020
0.091
0.018
0.009
0.002
0.015
0.038
0.040
0.023
0.023
0.030
0.028
0.031
0.045
0.017
0.019
APPENDIX A • DATA TABLES 135
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
KY
KY
KY
KY
KY
KY
KY
KY
KY
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
LA
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
MD
MD
MD
MD
MD
MD
MD
MD
MD
MD
MD
MD
County
OLDHAM CO
PERRY CO
PIKE CO
PULASKI CO
SCOTT CO
SIMPSON CO
TRIGG CO
WARREN CO
WHITLEY CO
ASCENSION PAR
BEAUREGARD PAR
BOSSIER PAR
CADDO PAR
CALCASIEU PAR
EAST BATON ROUGE PAR
GRANT PAR
IBERVILLE PAR
JEFFERSON PAR
LAFAYETTE PAR
LAFOURCHE PAR
LIVINGSTON PAR
ORLEANS PAR
OUACHITA PAR
POINTE COUPEE PAR
ST BERNARD PAR
ST CHARLES PAR
ST JAMES PAR
ST JOHN THE BAPTIST PAR
ST MARY PAR
WEST BATON ROUGE PAR
ANDROSCOGGIN CO
AROOSTOOK CO
CUMBERLAND CO
FRANKLIN CO
HANCOCK CO
KENNEBEC CO
KNOX CO
OXFORD CO
PENOBSCOT CO
PISCATAQUIS CO
SAGADAHOC CO
YORK CO
ALLEGANY CO
ANNE ARUNDEL CO
BALTIMORE CO
CALVERT CO
CARROLL CO
CECIL CO
CHARLES CO
FREDERICK CO
GARRETT CO
HARFORD CO
KENT CO
MONTGOMERY CO
1990
Population
33,263
30,283
72,583
49,489
23,867
15,145
10,361
76,673
33,326
58,214
30,083
86,088
248,253
168,134
380,105
17,526
31,049
448,306
164,762
85,860
70,526
496,938
142,191
22,540
66,631
42,437
20,879
39,996
58,086
19,419
105,259
86,936
243,135
29,008
46,948
115,904
36,310
52,602
146,601
18,653
33,535
164,587
74,946
427,239
692,134
51,372
123,372
71,347
101,154
150,208
28,138
182,132
17,842
757,027
CO Pb NO2
8-hr QMax AM
(ppm) (ug/m3) (ppm)
0.0108
0.0068
0.0052
3.9 0.04 0.0187
0.0103
0.0112
0.0055
3.3 0.08 0.0204
0.0073
0.0106
0.11
0.05 0.0152
0.0102
0.0200
03(1-hr)
2nd Max
(ppm)
0.120
0.091
0.101
0.102
0.106
0.113
0.100
0.123
0.106
0.111
0.107
0.123
0.131
0.102
0.120
0.122
0.100
0.110
0.117
0.092
0.090
0.103
0.108
0.105
0.101
0.118
0.105
0.128
0.120
0.125
0.102
0.107
0.072
0.094
0.068
0.124
0.120
0.136
0.116
0.112
0.119
0.124
0.123
0.108
0.132
0.117
0.122
03(8-hr)
4th Max
(ppm)
0.101
0.073
0.085
0.084
0.088
0.092
0.083
0.091
0.082
0.090
0.090
0.090
0.107.
0.084
0.091
0.091
0.088
0.090
0.089
0.076
0.078
0.075
0.086
0.086
0.081
0.087
0.091
0.083
0.089
0.094
0.077
0.077
0.060
0.077
0.061
0.091
0.089
0.111
0.094
0.092
0.095
0.101
0.105
0.095
0.099
0.098
0.097
PM10
2nd Max
(ug/m3)
50
47
37
44
45
57
64
61
56
64
36
99
68
31
66
46
54
43
52
48
33
44
S02
24-hr
(ppm)
0.010
0.012
0.017
0.012
0.026
0.036
0.019
0.036
0.025
0.017
0.012
0.021
136 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
MD
MD
MD
MA
MA
MA
MA
MA
MA
MA
MA
MA
MA
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
Ml
MN
MN
MN
MN
MN
MN
MN
MN
MN
MN
MN
MN
MS
MS
MS
MS
MS
MS
MS
County
PRINCE GEORGES CO
WICOMICO CO
BALTIMORE
BARNSTABLE CO
BERKSHIRE CO
BRISTOL CO
ESSEX CO
HAMPDEN CO
HAMPSHIRE CO
MIDDLESEX CO
NORFOLK CO
SUFFOLK CO
WORCESTER CO
ALLEGAN CO
BENZIE CO
BERRIEN CO
CALHOUN CO
CASS CO
CLINTON CO
DELTA CO
GENESEE CO
HURON CO
INGHAM CO
KALAMAZOO CO
KENT CO
LENAWEE CO
MACOMB CO
MASON CO
. MISSAUKEE CO
MUSKEGON CO
OAKLAND CO
OTTAWA CO
ST CLAIR CO
WASHTENAW CO
WAYNE CO
ANOKA CO
CARLTON CO
DAKOTA CO
HENNEPIN CO
KOOCHICHING CO
LAKE CO
OLMSTED CO
RAMSEY CO
ST LOUIS CO
SHERBURNE CO
STEARNS CO
WASHINGTON CO
ADAMS CO
COAHOMA CO
DE SOTO CO
HANCOCK CO
HARRISON CO
HINDS CO
JACKSON CO
CO
1990 8-hr
Population (ppm)
729,268 4.8
74,339
736,014 5.0
186,605
139,352
506,325
670,080
456,310 4.6
146,568
1,398,468 3.4
616,087
663,906 3.2
709,705 3.5
90,509
12,200
161,378
135,982
49,477
57,883
37,780
430,459
34,951
281,912
223,41 1
500,631 2.9
91,476
717,400 2.2
25,537
12,147
158,983
1,083,592 2.2
187,768
145,607
282,937
2,111,687 3.5
243,641 2.8
29,259
275,227 1.1
1,032,431 3.7
16,299
10,415
106,470
485,765 7.0
198,213 3.7
41,945
118,791 3.6
145,896
35,356
31,665
67,910
31,760
165,365
254,441 3.7
115,243
Pb NO2
QMax AM
(ug/m3) (ppm)
0.01 0.0258
0.0040
0.0077
. . 0.0145
0.0204
0.0058
0.03 0.0307
0.0187
0.01
0.01
0.00 . .
0.08 0.0230
0.14 0.0129
0.02 0.0256
0.02 0.0180
0.0106
0.0039
03(1-hr)
2nd Max
(ppm)
0.128
0.116
0.103
0.078
0.107
0.113
0.115
0.117
0.114
0.096
0.124
0.124
0.107
0.136
0.110
0.097
0.114
0.113
0.102
0.106
0.106
0.097
0.126
0.108
0.097
0.115
0.102
0.101
0.116
0.099
0.117
0.093
0.087
0.077
0.075
0.097
0.095
0.109
0.108
0.104
0.118
03(8-hr)
4th Max
(ppm)
0.104
0.091
0.084
0.088
0.100
0.093
0.093
0.098
0.087
.0.097
0.097
0.090
0.093
0.091
0.078
0.089
0.087
0.081
0.087
0.087
0.086
0.098
0.087
0.079
0.092
0.089
0.085
0.091
0.084
0.093
0.072
0.071
0.068
0.067
0.076
0.084
0.089
0.089
0.082
0.097
PM10
2nd Max
(ug/m3)
53
35
65
44
41
62
35
40
34
71
50
66
39
55
40
114
37
73
36
64
81
49
41
76
S02
24-hr
(ppm)
0.020
0.024
0.031
0.026
0.016
0.024
0.036
0.017
0.007
0.014
0.008
0.017
0.073
0.044
0.013
0.024
0.059
0.009
0.019
0.013
0.022
0.008
0.015
APPENDIX A • DATA TABLES 137
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
MS
MS
MS
MS
MS
MS
MS
MO
MO
MO
MO
MO
MO
MO
MO
MO
MO
MO
MO
MO
MO
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
MT
NE
NE
NE
NE
NV
NV
NV
NV
NV
NV
NV
NH
NH
NH
County
JONES CO
LAUDERDALE CO
LEE CO
MADISON CO
PANOLA CO
WARREN CO
WASHINGTON CO
BUCHANAN CO
CEDAR CO
CLAY CO
GREENE CO
HOLT CO
IRON CO
JACKSON CO
JEFFERSON CO
MONROE CO
PLATTE CO
ST CHARLES CO
STE GENEVIEVE CO
ST LOUIS CO
ST LOUIS
BIG HORN CO
BROADWATER CO
CASCADE CO
FLATHEAD CO
GALLATIN CO
GLACIER CO
JEFFERSON CO
LAKE CO
LEWIS AND CLARK CO
LINCOLN CO
MADISON CO
MISSOULA CO
PARK CO
PHILLIPS CO
RAVALLI CO
ROSEBUD CO
SANDERS CO
SILVER BOW CO
YELLOWSTONE CO
CASS CO
DAWSON CO
DOUGLAS CO
LANCASTER CO
CLARK CO
DOUGLAS CO
ELKO CO
LANDER CO
WASHOE CO
WHITE PINE CO
CARSON CITY
BELKNAP CO
CARROLL CO
CHESHIRE CO
1990
Population
62,031
75,555
65,581
53,794
29,996
47,880
67,935
83,083
12,093
153,411
207,949
6,034
10,726
633,232
171,380
9,104
57,867
212,907
16,037
993,529
396,685
11,337
3,318
77,691
59,218
50,463
12,121
7,939
21,041
47,495
17,481
5,989
78,687
14,562
5,163
25,010
10,505
8,669
33,941
113,419
21,318
19,940
416,444
213,641
741,459
27,637
33,530
6,266
254,667
9,264
40,443
49,216
35,410
70,121
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (ug/m3) (ppm) (ppm)
0.091
0.107
0.106
0.119
0.096
0.096
4.6 . 0.0130 0.133
4.0 . 0.0122 0.094
0.62
1.14
3.9 0.01 . 0.099
11.59 . 0.111
0.091
0.0132 0.123
0.0115 0.135
0.103
4.0 0.04 0.0225 0.122
6.0 . 0.0258 0.103
4.5 ..
5.0 . . 0.062
0.89
4.7 ..
4.9 ..
5.4 ..
7.7 0.25 . 0.090
6.0 . . 0.068
10.1 . . 0.108
1.8 . . 0.075
6.6 . . 0.093
0.083
4.5 . . 0.080
0.072
0.078
0.085
03(8-hr)
4th Max
(ppm)
0.078
0.088
0.086
0.089
0.082
0.087
0.095
0.071
0.073
0.091
0.079
0.090
0.097
0.090
0.092
0.079
0.070
0.058
0.092
0.069
0.075
0.070
0.067
0.064
0.068
0.073
PM10
2nd Max
(ug/m3)
45
32
47
56
124
43
68
48
36
62
71
144
66
118
73
78
75
108
99
107
34
73
21
53
76
153
68
97
106
87
85
188
58
59
139
S02
24-hr
(ppm)
0.005
0.121
0.008
0.042
0.084
0.010
0.049
0.014
0.005
0.021
0.027
0.038
0.010
0.030
0.032
0.012
0.032
0.032
0.023
138 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
NH
NH
NH
NH
NH
NH
NH
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NJ
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NM
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
County
COOS CO
GRAFTON CO
HILLSBOROUGH CO
MERRIMACK CO
ROCKINGHAM CO
STRAFFORD CO
SULLIVAN CO
ATLANTIC CO
BERGEN CO
BURLINGTON CO
CAMDEN CO
CUMBERLAND CO
ESSEX CO
GLOUCESTER CO
HUDSON CO
HUNTERDON CO
MERCER CO
MIDDLESEX CO
MONMOUTH CO
MORRIS CO
OCEAN CO
PASSAIC CO
UNION CO
BERNALILLO CO
CHAVES CO
DONA ANA CO
EDDY CO
GRANT CO
HIDALGO CO
LEA CO
LUNA CO
OTERO CO
SANDOVAL CO
SAN JUAN CO
SANTA FE CO
TAOS CO
VALENCIA CO
ALBANY CO
BRONX CO
BROOME CO
CHAUTAUQUA CO
CHEMUNG CO
COLUMBIA CO
DUTCHESS CO
ERIE CO
ESSEX CO
GREENE CO
HAMILTON CO
HERKIMER CO
JEFFERSON CO
KINGS CO
MADISON CO
MONROE CO
NASSAU CO
1990
Population
34,828
74,929
336,073
120,005
245,845
104,233
38,592
224,327
825,380
395,066
502,824
138,053
778,206
230,082
553,099
107,776
325,824
671 ,780
553,124
421 ,353
433,203
453,060
493,819
480,577
57,849
135,510
48,605
27,676
5,958
55,765
18,110
51,928
63,319
91,605
98,928
23,118
45,235
292,594
1,203,789
212,160
141,895
95,195
62,982
259,462
968,532
37,152
44,739
5,279
65,797
110,943
2,300,664
69,120
713,968
1 ,287,348
CO
8-hr
(ppm)
5.3
3.7
3.6
3.0
2.6
5.6
3.0
2.8
3.3
3.2
5.1
5.9
4.2
1.0
3.8
2.0
1.2
3.2
3.1
4.1
3.1
4.0
Pb NO2
QMax AM
(ug/m3) (ppm)
0.0148
0.0124
0.01 0.0219
0.0328
0.0269
0.0153
0.08 0.0191
0.0112
0.0419
0.0157
0.04 0.0101
0.0058
0.0093
0.0099
0.03 0.0145
0.0359
0.04 0.0208
0.14
0.0219
03(1-hr)
2nd Max
(ppm)
0.086
0.100
0.088
0.118
0.092
0.091
0.118
0.080
0.118
0.117
0.112
0.120
0.118
0.118
0.113
0.117
0.129
0.119
0.135
0.102
0.093
0.124
0.084
0.090
0.079
0.082
0.100
0.095
0.111
0.094
0.108
0.110
0.098
0.089
0.085
0.103
0.094
0.088
03(8-hr)
4th Max
(ppm)
0.076
0.084
0.074
0.085
0.079
0.067
0.091
0.097
0.098
0.087
0.098
0.089
0.096
0.095
0.099
0.093
0.097
0.104
0.089
0.074
0.082
0.075
0.072
0.071
0.069
0.079
0.078
0.095
0.082
0.089
0.094
0.079
0.080
0.070
0.088
0.082
0.076
PM10
2nd Max
(Mg/m3)
52
71
46
63
59
58
88
48
158
37
24
41
36
41
39
28
29
75
58
51
51
62
46
50
43
56
38
54
50
46
S02
24-hr
(ppm)
0.046
0.027
0.043
0.016
0.018
0.010
0.018
0.023
0.023
0.012
0.025
0.015
0.024
0.018
0.020
0.021
0.019
0.005
0.022
0.044
0.074
0.016
0.037
0.032
0.011
0.049
0.006
0.005
0.005
0.029
0.011
0.054
0.022
APPENDIX A • DATA TABLES 139
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NY
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
County
NEW YORK CO
NIAGARA CO
ONEIDA CO
ONONDAGA CO
ORANGE CO
PUTNAM CO
QUEENS CO
RENSSELAER CO
RICHMOND CO
ROCKLAND CO
SARATOGA CO
SCHENECTADY CO
SUFFOLK CO
ULSTER CO
WAYNE CO
WESTCHESTER CO
ALEXANDER CO
AVERY CO
BEAUFORT CO
BUNCOMBE CO
CABARRUS CO
CALDWELL CO
CAMDEN CO
CASWELL CO
CATAWBA CO
CHATHAM CO
CUMBERLAND CO
DAVIDSON CO
DAVIE CO
DUPLIN CO
DURHAM CO
EDGECOMBE CO
FORSYTH CO
FRANKLIN CO
GASTON CO
GRANVILLE CO
GUILFORD CO
HARNETT CO
HAYWOOD CO
HENDERSON CO
JOHNSTON CO
LENOIR CO
LINCOLN CO
MC DOWELL CO
MARTIN CO
MECKLENBURG CO
MITCHELL CO
NEW HANOVER CO
NORTHAMPTON CO
ONSLOW CO
ORANGE CO
PASQUOTANK CO
PERSON CO
PITT CO
1990
Population
1,487,536
220,756
250,836
468,973
307,647
83,941
1,951,598
154,429
378,977
265,475
181,276
149,285
1,321,864
165,304
89,123
874,866
27,544
14,867
42,283
174,821
98,935
70,709
5,904
20,693
118,412
38,759
274,566
126,677
27,859
39,995
181,835
56,558
265,878
36,414
175,093
38,345
347,420
67,822
46,942
69,285
81,306
57,274
50,319
35,681
25,078
511,433
14,433
120,284
20,798
149,838
93,851
31,298
30,180
107,924
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (ug/m3) (ppm) (ppm)
5.8 0.13 0.0397 0.109
1.4 0.04 . 0.101
0.091
3.0 . . 0.092
0.14 . 0.104
0.112
2.2 . . 0.119
0.02 . 0.129
0.099
4.4 . . 0.090
0.143
0.093
0.103
0.109
0.133
0.096
0.114
0.114
0.092
0.119
0.106
4.2 . . 0.112
0.123
0.104
5.2 . . 0.112
0.107
5.4 . 0.0170 0.123
0.110
0.9 . . 0.130
3.6 . . 0.115
0.109
0.111
0.109
0.117
, 0.094
5.0 . 0.0177 0.135
0.102
0.109
3.8
0.117
0.109
03(8-hr)
4th Max
(ppm)
0.075
0.089
0.076
0.082
0.088
0.093
0.089
0.090
0.076
0.069
0.095
0.081
0.085
0.090
0.096
0.082
0.090
0.098
0.079
0.096
0.090
0.098
0.102
0.091
0.095
0.091
0.100
0.099
0.098
0.097
0.102
0.092
0.092
0.090
0.084
0.110
0.087
0.087
0.093
0.091
PM10
2nd Max
(ug/m3)
114
55
45
62
39
48
47
45
44
48
40
52
55
46
44
47
48
47
43
63
41
54
63
49
43
48
73
52
41
42
40
42
S02
24-hr
(ppm)
0.038
0.016
0.009
0.014
0.033
0.009
0.024
0.013
0.033
0.009
0.017
0.009
0.023
0.006
0.011
0.026
0.016
140 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by iCounty, 1998 (continued)
State
NC
NC
NC
NC
NC
NC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
County
ROCKINGHAM CO
ROWAN CO
SWAIN CO
WAKE CO
WAYNE CO
YANCEY CO
BILLINGS CO
BURLEIGH CO
CASS CO
DUNN CO
GRAND FORKS CO
MC KENZIE CO
MC LEAN CO
MERCER CO
MORTON CO
OLIVER CO
STARK CO
STEELE CO
WILLIAMS CO
ADAMS CO
ALLEN CO
ASHTABULA CO
ATHENS CO
BELMONT CO
BUTLER CO
CLARK CO
CLERMONT CO
CLINTON CO
COLUMBIANA CO
CUYAHOGA CO
DELAWARE CO
FRANKLIN CO
FULTON CO
GEAUGA CO
GREENE CO
HAMILTON CO
HANCOCK CO
JEFFERSON CO
KNOX CO
LAKE CO
LAWRENCE CO
LICKING CO
LOGAN CO
LORAIN CO
LUCAS CO
MADISON CO
MAHONING CO
MEDINA CO
MEIGS CO
MIAMI CO
MONROE CO
MONTGOMERY CO
MORGAN CO
OTTAWA CO
1990
Population
86,064
110,605
11,268
423,380
104,666
. 15,419
1,108
60,131
102,874
4,005
70,683
6,383
1 0,457
9,808
23,700
2,381
22,832
2,420
21,129
25,371
109,755
99,821
59,549
71 ,074
291 ,479
147,548
150,187
35,415
108,276
1,412,140
66,929
961 ,437
38,498
81,129
136,731
866,228
65,536
80,298
47,473
215,499
61,834
128,300
42,310
271,126
462,361
37,068
264,806
122,354
22,987
93,182
15,497
573,809
14,194
40,029
CO Pb N02 03(1-hr)
8-hr QMax AM 2nd Max
(ppm) (ug/m3) (ppm) (ppm)
0.112
0.8 . . 0.126
0.090
5.4 . . 0.124
0.083
0.060
0.068
' 0.065
0.0047 0.069
0.0031 0.067
0.0026 0.068
0.102
0.116
0.02 . 0.118
0.125
0.117
0.118
0.0146
6.4 0.65 0.0273 0.113
0.119
3.7 0.03 . 0.113
. . 0.35
0.117
0.116
4.4 0.01 0.0293 0.124
3.6 . . 0.089
0.102
1.6 . ' . 0.123
0.136
0.112
0.24 . 0.099
0.105
2.1 . . 0.106
0.112
0.114
0.106
0.109
3.4 0.01 . 0.112
03(8-hr)
4th Max
(ppm)
0.101
0.078
0.106
0.059
0.058
0.059
0.089
0.096
0.092
0.100
0.099
0.103
0.094
0.102
0.096
0.088
0.097
0.092
0.077
0.091
0.100
0.101
0.096
0.081
0.088
0.090
0.099
0.097
0.092
0.090
0.093
PM10
2nd Max
(ug/m3)
39
63
44
32
81
28
40
48
46
39
54
74
88
117
83
43
84
44
65
50
50
80
51
62
54
61
54
S02
24-hr
(ppm)
0.012
0.006
0.004
0.005
0.005
0.013
0.008
0.018
0.116
0.014
0.010
0.013
0.036
0.017
0.020
0.022
0.016
0.021
0.049
0.037
0.019
0.029
0.047
0.057
0.020
0.020
0.024
0.023
0.026
0.022
0.070
APPENDIX A
DATA TABLES
141
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OH
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
OR
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
County
PORTAGE CO
PREBLE CO
HIGHLAND CO
SANDUSKY CO
SCIOTO CO
SENECA CO
STARK CO
SUMMIT CO
TRUMBULL CO
TUSCARAWAS CO
UNION CO
WARREN CO
WASHINGTON CO
WOOD CO
WYANDOT CO
CLEVELAND CO
COMANCHE CO
GARFIELD CO
KAY CO
LATIMER CO
MC CLAIN CO
MAYES CO
MUSKOGEE CO
OKLAHOMA CO
OKMULGEE CO
TULSA CO
CLACKAMAS CO
COLUMBIA CO
DESCHUTES CO
JACKSON CO
JOSEPHINE CO
KLAMATH CO
LAKE CO
LANE CO
MARION CO
MULTNOMAH CO
UMATILLA CO
UNION CO
YAMHILL CO
ADAMS CO
ALLEGHENY CO
ARMSTRONG CO
BEAVER CO
BERKS CO
BLAIR CO
BUCKS CO
CAMBRIA CO
CARBON CO
CENTRE CO
CHESTER CO
CLEARFIELD CO
DAUPHIN CO
DELAWARE CO
ERIE CO
1990
Population
142,585
40,113
126,137
61,963
80,327
59,733
367,585
514,990
227,813
84,090
31,969
113,909
62,254
113,269
22,254
174,253
111,486
56,735
48,056
10,333
22,795
33,366
68,078
599,61 1
36,490
503,341
278,850
37,557
74,958
146,389
62,649
57,702
7,186
282,912
228,483
583,887
59,249
23,598
65,551
78,274
1,336,449
73,478
186,093
336,523
130,542
541,174
163,029
56,846
123,786 '
376,396
78,097
237,813
547,651
275,572
CO
8-hr
(ppm)
3.5
3.0
2.6
1.8
4.1
4.7
4.4
5.3
4.7
4.5
4.6
4.6
4.6
0.6
3.8
1.5
3.2
1.2
3.5
3.1
3.0
5.1
Pb NO2
QMax AM
(ug/m3) (ppm)
0.02
0.0124
0.0079
0.0075
0.0099
0.0150
0.03
0.02
0.05
0.30
0.0034
0.06 0.0310
0.05 0.0187
0.71 0.0208
0.0126
0.0180
0.04 0.0152
0.12
0.04 0.0185
0.04 0.0191
0.0142
03(1-hr)
2nd Max
(ppm)
0.110
0.102
0.115
0.114
0.115
0.112
0.123
0.115
0.097
0.111
0.093
0.108
0.104
0.106
0.091
0.109
0.106
0.119
0.136
0.093
0.117
0.106
0.112
0.118
0.113
0.116
0.106
0.1.14
0.115
0.124
0.113
0.116
0.116
0.125
0.122
03(8-hr)
4th Max
(ppm)
0.097
0.081
0.098
0.097
0.101
0.088
0.097
0.091
0.083
0.093
0.085
0.093
0.087
0.087
0.081
' 0.090
0.092
0.093
0.081
0.066
0.085
0.078
0.077
0.104
0.100
0.098
0.092
0.098
0.096
0.098
0.092
0.101
0.097
0.099
0.098
PM10
2nd Max
(Mg/m3)
66
72
54
56
58
70
63
68
92
41
70
46
56
36
69
70
51
80
75
78
59
68
57
130
86
58
58
59
64
66
65
72
64
S02
24-hr
(ppm)
0.014
0.029
0.044
0.049
0.022
0.016
0.007
0.059
0.065
0.094
0.025
0.032
0.024
0.027
0.021
0.035
0.068
142 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
PA
Rl
Rl
Rl
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SC
SD
SD
SD
TN
TNI
TN
County
FRANKLIN CO
GREENE CO
LACKAWANNA CO
LANCASTER CO
LAWRENCE CO
LEHIGH CO
LUZERNE CO
LYCOMING CO
MERCER CO
MONROE CO
MONTGOMERY CO
NORTHAMPTON CO
PERRY CO
PHILADELPHIA CO
SCHUYLKILL CO
WARREN CO
WASHINGTON CO
WESTMORELAND CO
YORK CO
KENT CO
PROVIDENCE CO
WASHINGTON CO
ABBEVILLE CO
AIKEN CO
ANDERSON CO
BARNWELL CO
BEAUFORT CO
BERKELEY CO
CHARLESTON CO
CHEROKEE CO
CHESTER CO
COLLETON CO
DARLINGTON CO
EDGEFIELD CO
FAIRFIELD CO
FLORENCE CO
GEORGETOWN CO
GREENVILLE CO
GREENWOOD CO
LEXINGTON CO'
OCONEE CO
PICKENS CO
RICHLAND CO
SPARTANBURG CO
SUMTER CO
UNION CO
WILLIAMSBURG CO
YORK CO
BROOKINGS CO
MINNEHAHA CO
PENNINGTON CO
ANDERSON CO
BLOUNT CO
BRADLEY CO
1990
Population
121,082
39,550
219,039
422,822
96,246
291,130
328,149
118,710
121,003
95,709
678,111
247,105
41,172
1,585,577
152,585
• 45,050
204,584
370,321
339,574
161,135
596,270
110,006
23,862
120,940
145,196
20,293
86,425
128,776
295,039
44,506
32,170
34,377
61,851
18,375
22,295
114,344
46,302
320,167
59,567
167,611
57,494
93,894
. 285,720
226,800
102,637
30,337
36,815
131,497
25,207
123,809
81,343
68,250
85,969
73,712
CO Pb
8-hr QMax
(ppm) (ug/m3)
1.9
1.9 0.04
2.4
2.9
3.1
0.04
1.0
1.8 0.04
2.5 0.00
4.9 1 .64
1.4
2.0
2.3 0.04
2.4 0.05
4.7
0.02
0.03
2.9 0.03
0.01
0.02
4.3 0.02
0.01
3.7 0.01
0.01
0.01
0.02
NO2
AM
(ppm)
0.0160
0.0149
0.0188
0.0163
0.0148
0.0193
0.0170
0.0060
0.0340
0.0172
0.0178
0.0186
0.0249
0.0095
0.0166
0.0137
0.0145
03(1-hr)
2nd Max
(ppm)
0.120
0.110
0.108
0.119
0.096
0.106
0.102
0.099
0.121
0.108
0.126
0.111
0.110
0.116
0.127
0.101
0.112
. 0.109
0.098
0.101
0.114
0.111
0.125
0.111
0.106
0.096
0.120
0.122
0.099
0.108
0.119
0.106
0.109
0.116
0.112
0.105
0.091
0.114
0.107
0.120
03(8-hr)
4th Max
(ppm)
0.104
0.100
0.089
0.101
0.077
0.095
0.088
0.084
0.106
0.091
0.103
0.089
0.092
0.095
0.108
0.082
0.095
0.087
0.077
0.080
0.091
0.098
0.102
0.095
0.083
0.081
0.096
0.093
0.087
0.089
0.091
0.093
0.096
0.098
0.097
0.087
0.079
0.087
0.088
0.110
PM10
2nd Max
(ug/m3)
54
62
93
51
53
75
54
37
53
105
62
71
60
32
59
51
44
57
53
75
58 .
188
145
48
57
54
54
113
64
50
S02
24-hr
(ppm)
0.021
0.026
0.020
0.032
0.030
0.022
0.021
0.029
0.014
0.022
0.033
0.012
0.030
0.026
0.098
0.043
0.039
0.023
0.027
0.013
0.004
0.015
0.022
0.006
0.010
0.024
0.038
0.031
APPENDIX A • DATA TABLES 143
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TN
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
UT
UT
County
COFFEE CO
DAVIDSON CO
HAMBLEN CO
HAMILTON CO
HAWKINS CO
HAYWOOD CO
HUMPHREYS CO
JEFFERSON CO
KNOX CO
LAWRENCE CO
MC MINN CO
MADISON CO
MAURY CO
MONTGOMERY CO
POLK CO
PUTNAM CO
ROANE CO
RUTHERFORD CO
SEVIER CO
SHELBY CO
STEWART CO
SULLIVAN CO
SUMNER CO
UNION CO
WASHINGTON CO
WILLIAMSON CO
WILSON CO
BEXAR CO
BOWIE CO
BRAZORIA CO
BREWSTER CO
CAMERON CO
CASS CO
COLLIN CO
DALLAS CO
DENTON CO
ELLIS CO
EL PASO CO
GALVESTON CO
GREGG CO
HARRIS CO
HIDALGO CO
JEFFERSON CO
LUBBOCK CO
MARION CO
NUECES CO
ORANGE CO
SMITH CO
TARRANT CO
TRAVIS CO
VICTORIA CO
WEBB CO
CACHE CO
DAVIS CO
1990
Population
40,339
510,784
50,480
285,536
44,565
19,437
15,795
33,016
335,749
35,303
42,383
77,982
54,812
100,498
13,643
51,373
47,227
118,570
51,043
826,330
9,479
143,596
103,281
13,694
92,315
81,021
67,675
1,185,394
81,665
191,707
8,681
260,120
29,982
264,036
1,852,810
273,525
85,167
591,610
217,399
104,948
2,818,199
383,545
239,397
222,636
9,984
291,145
80,509
151,309
1,170,103
576,407
74,361
133,239
70,183
187,941
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (ug/rn3) (ppm) (ppm)
0.0045 0.096
5.6 . 0.0109 0.120
0.131
0.128
0.126
3.9 0.00 . 0.138
0.105
0.0151
0.01
0.106
0.33
0.104
0.120
5.4 2.02 0.0285 0.130
3.4 0.31 0.0170 0.115
2.1 . 0.0131 0.127
1.25 . 0.114
0.105
4.6 . . 0.0240 0.121
0.111
0.077
3.2 0.01 . 0.081
0.67 . 0.118
4.4 0.10 0.0200 0.118
0.122
0.30 . 0.130
8.3 0.14 0.0310 0.125
0.0030 0.168
0.129
5.2 . 0.0230 0.203
0.086
0.0079 0.143
0.094
0.102
0.0089 0.110
0.108
2.5 . 0.0140 0.128
1.1 . 0.0040 0.115
0.097
3.9 0.02 . 0.097
5.0 . . 0.080
3.1 . 0.0201 0.122
03(8-hr)
4th Max
(ppm)
0.081
0.091
0.103
0.098
0.107
0.114
0.090
0.090
0.087
0.106
0.103
0.097
0.107
0.096
0.085
0.090
0.090
0.070
0.071
0.097
0.094
0.101
0.097
0.092
0.113
0.104
0.121
0.071
0.096
0.076
0.082
0.076
0.090
0.102
0.088
0.078
0.067
0.068
0.096
PM10
2nd Max
(ug/m3)
66
57
64
40
84
38
75
45
67
65
50
87
174
47
61
62
75
68
67
258
69
129
44
68
50
76
S02
24-hr
(ppm)
0.015
0.024
0.036
0.057
0.009
0.019.
0.045
0.020
0.111
0.022
0.041
0.013
0.039
0.046
0.009
0.005
0.008
0.006
0.023
0.027
0.039
0.024
0.050
,0.029
0.010
144 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by C'ounty, 1998 (continued)
State
UT
UT
UT
UT
UT
VT
VT
VT
VT
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA '
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
VA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
WA
County
GRAND CO
SALT LAKE CO
SAN JUAN CO
UTAH CO
WEBER CO
BENNINGTON CO
CHITTENDEN CO
RUTLAND CO
WASHINGTON CO
ARLINGTON CO
CAROLINE CO
CARROLL CO
CHARLES CITY CO
CHESTERFIELD CO
CULPEPER CO
FAIRFAX CO
FAUQUIER CO
FREDERICK CO
HANOVER CO
HENRICO CO
KING WILLIAM CO
LOUDOUN CO
MADISON CO
NORTHUMBERLAND CO
PRINCE WILLIAM CO
ROANOKE CO
ROCKINGHAM CO
STAFFORD CO
TAZEWELL CO
WARREN CO
WISE CO
WYTHE CO
ALEXANDRIA
CHARLOTTESVILLE
CHESAPEAKE
FREDERICKSBURG
HAMPTON
NEWPORT NEWS
NORFOLK
RICHMOND
ROANOKE
SUFFOLK
WINCHESTER
ASOTIN CO
BENTON CO
CHELAN CO
CLALLAM CO
CLARK CO
COWLITZ CO
KING CO
KITSAP CO
KITTITAS CO
KLICKITAT CO
LEWIS CO
1990
Population
6,620
725,956
12,621
263,590
158,330
35,845
131,761
62,142
54,928
170,936
19,217
26,594
6,282
209,274
27,791
818,584
48,741
45,723
63,306
217,881
10,913
86,129
11,949
10,524
215,686
79,332
57,482
61,236
45,960
26,142
39,573
25,466
111,183
40,341
151,976
19,027
133,793
170,045
261,229
203,056
96,397
52,141
21,947
17,605
112,560
52,250
56,464
238,053
82,119
1,507,319
189,731
26,725
16,616
59,358
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (ug/m3) (ppm) (ppm)
5.7 0.09 0.0272 0.124
0.078
6.0 . 0.0239 0.114
7.5 . '0.0243 0.111
0.085
2.4 . 0.0175 0.082
2.4 . 0.0127
2.3 . 0.0253 0.112
0.121
0.0117 0.116
0.116
3.3 0.03 0.0234 0.127
0.111
0.113
0.125
0.121
0.116
0.115
0.0146 0.124
0.0141 0.126
0.126
0.098
3.5 . 0.0272 0.114
0.104
2.8 . .
6.2 . 0.0194
1.9 0.01 0.0212
3.9 ..
0.105
0.062
5.5 . 0.0121 0.097
0.0073 0.094
5.5 2.03 0.0204 0.135
. . . . 0.077
0.065
-&T3Zar«Z.:ZSt:jZZ<£Z2.
03(8-hr)
4th Max
(ppm)
0.095
0.071
0.090
0.090
0.075
0.073
0.098
0.095
0.092
0.090
0.103
0.093
0.098
0.100
0.096
0.102
0.098
0.098
0.099
0.092
0.087
0.094
0.090
0.087
0.046
0.070
0.070
0.085
0.063
0.056
PM10
2nd Max
(Mg/m3)
52
105
80
71
54
48
49
36
39
45
48
44
50
55
38
45
40
49
48
41
47
49
53
64
48
86
90
46
39
26
45 '
67
24
72
S02
24-hr
(ppm)
0.010
0.008
0.029
0.019
0.025
0.009
0.009
0.022
0.018
0.021
0.016
0.007
0.016
APPENDIX A
DATA TABLES
145
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
WA
WA
WA
WA
WA
WA
WA
WA
WA
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
WV
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
Wl
WY
WY
WY
County
PIERCE CO
SKAGIT CO
SNOHOMISH CO
SPOKANE CO
STEVENS CO
THURSTON CO
WALLA WALLA CO
WHATCOM CO
YAKIMA CO
BROOKE CO
CABELL CO
FAYETTE CO
GREENBRIER CO
HANCOCK CO
KANAWHA CO
MARSHALL CO
MONONGALIA CO
OHIO CO
PUTNAM CO
WAYNE CO
WOOD CO
BROWN CO
COLUMBIA CO
DANE CO
DODGE CO
DOOR CO
DOUGLAS CO
FLORENCE CO
FOND DU LAC CO
JEFFERSON CO
KENOSHA CO
KEWAUNEE CO
MANITOWOC CO
MARATHON CO
MILWAUKEE CO
ONEIDA CO
OUTAGAMIE CO
OZAUKEE CO
POLK CO
RACINE CO
ROCK CO
ST CROIX CO
SAUK CO
SHEBOYGAN CO
VERNON CO
VILAS CO
WALWORTH CO
WASHINGTON CO
WAUKESHA CO
WINNEBAGO CO
WOOD CO
ALBANY CO
CAMPBELL CO
CONVERSE CO
1990
Population
586,203
79,555
465,642
361,364
30,948
161,238
48,439
127,780
188,823
26,992
96,827
47,952
34,693
35,233
207,619
37,356
75,509
50,871
42,835
41,636
86,915
194,594
45,088
367,085
76,559
25,690
41,758
4,590
90,083
67,783
128,181
18,878
80,421
115,400
959,275
31,679
140,510
72,831
34,773
175,034
139,510
50,251
46,975
103,877
25,617
17,707
75,000 •
95,328
304,715
140,320
73,605
30,797
29,370
11,128
CO Pb NO2 O3(1-hr)
8-hr QMax AM 2nd Max
(ppm) (ug/m3) (ppm) (ppm)
5.8 . . 0.126
0.052
5.1 ..
6.8 . . 0.082
4.8 . . 0.105
0.070
5.1 ..
0.136
0.113
13.2 . 0.0145 0.099
2.0 . 0.0221 0.115
3.5 . . 0.104
0.111
0.098
0.089
0.089
0.100
0.114
0.086
0.094
0.093
0.127
0.107
0.0034 0.114
0.098
2.5 . 0.0212 0.129
0.086
0.086
0.134
0.6 . . 0.090
3.0 . . 0.124
0.100
0.090
0.0042 0.089
0.134
0.082
0.100
0.103
2.1 . . 0.097
0.084
03(8-hr)
4th Max
(ppm)
0.085
0.042
0.070
0.074
0.056
0.105
0.102
0.088
0.091
0.087
0.094
0.077
0.076
0.076
0.081
0.092
0.076
0.078 ,
0.082
0.093
0.091
0.097
0.077
0.093
0.070
0.072
0.095
0.078
0.084
0.084
0.073
0.080
0.095
0.073
0.084
0.079
0.077
0.074
PM10
2nd Max
(ug/m3)
62
44
89
82
47
136
32
81
63
45
119
42
53
48
56
53
43
54
79
44
'59 .
64
41
27
62
44
66
77
S02
24-hr
(ppm)
0.020
0.042
0.009
0.015
0.062
0.023
0.014
0.067
0.037
0.061
0.041
0.040
0.038
0.089
0.011
0.016
0.031
0.022
0.044
0.020
146 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-12. Maximum Air Quality Concentrations by County, 1998 (continued)
State
WY
WY
WY
WY
WY
WY
WY
CO
Pb
NO2
O3(1-hr) =
O3 (8-hr) =
PM,0 =
so;° .
PPM
ug/m3 =
CO Pb NO2 O3(1-hr) O3(8-hr)
County 1990 8-hr QWlax AM 2nd Max 4th Max
Population (ppm) (ug/m3) (ppm) (ppm) (ppm)
FREMONT CO 33,662 ... .
LARAMIE CO 73,142 ... .
NATRONACO 61,226 ... .
PARK CO 23,178 ... .
SHERIDAN CO 23,562 ... .
SWEETWATER CO 38,823 ... .
TETON CO 11,172 . . . 0.072 0.066
Highest second maximum non-overlapping 8-hour concentration (Applicable NAAQS is 9 ppm)
Highest quarterly maximum concentration (Applicable NAAQS is 1.5 \ig/mS)
Highest arithmetic mean concentration (Applicable NAAQS is 0.053 ppm)
Highest second daily maximum 1 -hour concentration (Applicable NAAQS !s 0. 12 ppm)
Highest fourth daily maximum 8-hour concentration (Applicable NAAQS is 0.08 ppm)
Highest second maximum 24-hour concentration (Applicable NAAQS is 150 vg/m3)
Highest second maximum 24-hour concentration (Applicable NAAQS is 0. 14 ppm)
Units are parts per million
Units are micrograms per cubic meter
PM10
2nd Max
(ug/m3)
70
31
37
51
82
70
64
S02
24-hr
(ppm)
Data from exceptional events not included.
Note: The reader is cautioned that this summary is not adequate in itself to numerically rank counties according to their air quality. The monitoring data
represent the quality.of air in the vicinity of the monitoring site but may not necessarily represent urban-wide air quality.
APPENDIX A • DATA TABLES 147
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1998
Metropolitan Statistical Area
ABILENE. TX
AGUADILLA, PR
AKRON, OH
ALBANY, GA
ALBANY-SCHENECTADY-TROY, NY
ALBUQUERQUE, MM
ALEXANDRIA, LA
ALLENTOWN-BETHLEHEM-EASTON, PA
ALTOONA, PA
AMARILLO, TX
ANCHORAGE, AK
ANN ARBOR, Ml
ANNISTON, AL
APPLETON-OSHKOSH-NEENAH, Wl
ARECIBO, PR
ASHEVILLE, NC
ATHENS, GA
ATLANTA, GA
ATLANTIC-CAPE MAY, NJ
AUGUSTA-AIKEN, GA-SC
AURORA-ELGIN, IL
AUSTIN-SAN MARCOS, TX
BAKERSFIELD, CA
BALTIMORE, MD
BANGOR, ME
BARNSTABLE-YARMOUTH, MA
BATON ROUGE, LA
BEAUMONT-PORT ARTHUR, TX
BELLINGHAM, WA
BENTON HARBOR, Ml
BERGEN-PASSAIC, NJ
BILLINGS, MT
BILOXI-GULFPORT-PASCAGOULA, MS
BINGHAMTON, NY
BIRMINGHAM, AL
BISMARCK, ND
BLOOMINGTON, IN
BLOOMINGTON-NORMAL, IL
BOISE CITY, ID
BOSTON, MA-NH
BOULDER-LONGMONT, CO
BRA20RIA, TX
BREMERTON, WA
BRIDGEPORT, CT
BROCKTON, MA
BROWNSVILLE-HARLINGEN-SAN BENITO, TX
BRYAN-COLLEGE STATION, TX
BUFFALO-NIAGARA FALLS, NY
BURLINGTON, VT
CAGUAS, PR
CANTON-MASSILLON, OH
CASPER, WY
CEDAR RAPIDS, IA
CHAMPAIGN-URBANA, IL
1990
Population
119,655
128,172
657,575
112,561
861,424
589,131
131,556
595,081
130,542
187,547
226,338
490,058
116,034
315,121
155,005
191,774
126,262
2,959,950
319,416
415,184
356,884
846,227
543,477
2,382,172
91,629
134,954
528,264
361,226
127,780
161,378
1,278,440
113,419
312,368
264,497
840,140
83,831
108,978
129,180
295,851
3,227,707
225,339
191,707
189,731
443,722
236,409
260,120
121,862
1,189,288
151,506
279,501
394,106
61,226
168,767
173,025
CO
8-hr
(ppm)
ND
ND
3
ND
4
6
ND
3
1
ND
8
ND
ND
ND
ND
ND
ND
4
ND
ND
ND
1
3
5
ND
ND
4
ND
ND
ND
4
5
ND
ND
4
ND
ND
ND
4
3
5
ND
ND
3
ND
3
ND
3
2
ND
4
ND
3
ND
Pb
QMax
(Mg/m3)
ND
ND
0.02
ND
0.03
ND
ND
0.12
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.01
ND
0.02
ND
ND
0.00
0.01
ND
ND
0.05
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.03
ND
ND
ND
ND
ND
0.01
ND
0.04
ND
ND
ND
ND
ND
ND
N02
AM
(ppm)
ND
ND
ND
ND
0.015
0.016
ND
0.017
0.013
ND
ND
ND
ND
ND
ND
ND
ND
0.024
ND
ND
ND
0.004
0.024
0.026
ND
ND
0.019
0.009
ND
ND
IN
ND
0.004
ND
0.009
ND
ND
ND
0.020
0.031
ND
ND
ND
0.018
0.008
ND
ND
0.021
0.018
ND
ND
ND
ND
ND
03
1-hr
(ppm)
ND
ND
0.11
ND
0.10
0.09
ND
0.11
0.11
ND'
ND
0.10
ND
0.09
ND
0.11
ND
0.16
0.12
0.12
ND
0.12
0.16
0.14
0.09
ND
0.13
0.14
0.07
0.14
0.10
ND
0.12
ND
0.14
ND
ND
ND
ND
0.11
0.11
0.11
ND
0.13
0.11
0.08
ND
0.11
ND
ND
0.12
ND
0.08
0.11
03
8-hr
(ppm)
ND
ND
0.10
ND
0.08
0.07
ND
0.10
0.10
ND
ND
0.09
ND
. 0.07
ND
0.09
ND
0.13
0.09
0.10
ND
0.09
0.12
0.11
0.08
ND
0.11
0.10
0.06
0.09
0.09
ND
0.10
ND
0.11
ND
ND
ND
ND
0.10
0.09
0.09
ND
0.10
0.09
0.07
ND
0.09
ND
ND
0.10
ND
0.07
0.08
PM10
Wtd AM
dig/hi")
ND
ND
24
IN
21
17*
ND
IN
IN
ND
26
ND
IN
ND
ND
20
ND
31
ND
28
ND
ND
40
31
18
ND
32*
ND
13
ND
38*
ND
IN
IN
36
16
ND
ND
27
32
IN
ND
13
21
ND
25*
ND
24
21
ND
26
17
25
24
PM10
2nd Max
(pg/m3)
ND
ND
70
66
58
87
ND
41
58
ND
98
ND
IN
ND
ND
55
ND
71
ND
60
ND
ND
131
65
40
ND
64*
ND
31
ND
59*
ND
IN
51
109
32
ND
ND
67
71
45
ND
24
46
ND
62*
ND
55
54
ND
58
37
76
51
S02
AM
(ppm)
ND
ND
0.010
0.001
0.004
ND
ND
0.011
0.008
ND
ND
ND
ND
ND
ND
ND
ND
0.005
0.003
0.003
ND
ND
ND
0.007
ND
ND
0.007
0.008
0.005
ND
0.004
0.006
0.003
ND
0.007
0.006
ND
ND
ND
0.010 .
ND
ND
ND
0.007
ND
0.001
ND
0.009
0.002
ND
0.007
ND
0.005
0.003
S02
24-hr
(ppm)
ND
ND
0.044
0.006
0.016
ND
ND
0.033
0.032
ND
ND
ND
ND
ND
ND
ND
ND
0.019
0.010
0.011
ND
ND
ND
0.020
ND
ND
0.036
0.050
0.015
ND
0.018
0.032
0.022
ND
0.032
0.116
ND
ND
ND
0.036
ND
ND
ND
0.024
ND
0.005
ND
0.049
0.008
ND
0.029
ND
0.020
0.019
148 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-13. Maximum Air Quality Concentrations by Metropolitan1 Statistical Area, 1998 (continued)
Metropolitan Statistical Area
CHARLESTON-NORTH CHARLESTON, SC
CHARLESTON, WV
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC
CHARLOTTESVILLE, VA
CHATTANOOGA, TN-GA
CHEYENNE, WY
CHICAGO, IL
CHICO-PARADISE, CA
CINCINNATI, OH-KY-IIM
CLARKSVILLE-HOPKINSVILLE, TN-KY
CLEVELAND-LORAIN-ELYRIA, OH
COLORADO SPRINGS, CO
COLUMBIA, MO
COLUMBIA, SC
COLUMBUS, GA-AL
COLUMBUS, OH
CORPUS CHRISTI, TX
CUMBERLAND, MD-WV
DALLAS, TX
DANBURY, CT
DANVILLE, VA
DAVENPORT-MOLINE-ROCK ISLAND, IA-IL
DAYTON-SPRINGFIELD, OH
DAYTONA BEACH, FL
DECATUR, AL
DECATUR, IL
DENVER, CO
DES MOINES, IA
DETROIT, Ml
DOTHAN, AL
DOVER, DE
DUBUQUE, IA
DULUTH-SUPERIOR, MN-WI
DUTCHESS COUNTY, NY
EAU CLAIRE, Wl
EL PASO, TX
ELKHART-GOSHEN, IN
ELM IRA, NY
ENID, OK
ERIE, PA
EUGENE-SPRINGFIELD, OR
EVANSVILLE-HENDERSON, IN-KY
FARGO-MOORHEAD, ND-MN
FAYETTEVILLE, NC
FAYETTEVILLE-SPRINGDALE-ROGERS, AR
FITCHBURG-LEOMINSTER, MA
FLAGSTAFF, AZ-UT
FLINT, Ml
FLORENCE, AL
FLORENCE, SC
FORT COLLINS-LOVELAND, CO
FORT LAUDERDALE, FL
FORT MYERS-CAPE CORAL, FL
FORT FIERCE-PORT ST. LUCIE, FL
1990
Population
506,875
250,454
1,162,093
131,107
424,347
73,142
7,410,858
182,120
1,526,092
169,439
2,202,069
397,014
112,379
453,331
260,860
1,345,450
349,894
101,643
2,676,248
193,597
108,711
350,861
951,270
399,413
131,556
117,206
1,622,980
392,928
4,266,654
130,964
110,993
86,403
239,971
259,462
137,543
591,610
156,198
95,195
56,735
275,572
282,912
278,990
153,296
274,566
259,462
138,165
101,760
430,459
131,327
114,344
186,136
1,255,488
335,113
251,071
CO
8-hr
(ppm)
3
2
5
ND
ND
ND
5
4
4
ND
6
4
ND
4
ND
4
ND
ND
4
ND
ND
ND
3
ND
ND
ND
5
10
4
ND
ND
ND
4
ND
ND
8
ND
ND
ND
5
5
4
ND
4
ND
ND
ND
ND
ND
ND
4
4
ND
ND
Pb
QMax
(Mg/rn3)
0.03
ND
0.02
ND
ND
ND
0.10
0.00
0.01
ND
0.65a
0.01
ND
0.01
0.58b
0.03°
ND
ND
0.67d
ND
ND
0.01
0.01
ND
ND
0.02
0.11
ND
0.08
ND
ND
ND
ND
ND
ND
0.14
ND
ND
ND
ND
0.02
ND
ND
ND
ND
ND
ND
0.01
ND
0.01
ND
0.03
ND
ND
NO2
AM
(ppm)
0.010
0.022
0.018
ND
ND
ND
0.032
0.013
0.029
ND
0.027
0.020
ND
0.014
ND
ND
ND
ND
0.020
ND
ND
ND
ND
ND
ND
ND
0.035
ND
0.023
ND
ND
ND
ND
ND
ND
0.031
ND
ND
0.008
0.014
ND
0.018
IN
ND
ND
ND
ND
ND
ND
ND
ND
0.010
ND
ND
03
1-hr
(ppm)
0.11
0.12
0.14
ND
0.13
ND
0.11
0.10
0.12
0.11
0.12
0.07
ND
0.12
0.11
0.12
0.10
ND
0.13
0.12
ND
0.10
0.13
•0.10
0.10
0.09
0.12
0.08
0.13
ND
0.13
ND
0.08
0.11
ND
0.13
0.11
0.09
ND
0.12
0.11
0.12
0.07
0.11
ND
ND
0.08
0.11
ND
ND
0.09
0.11
0.11
0.10
03
8-hr
(ppm)
0.08 '
0.09
0.11
ND
0.10
ND
0.09
0.08
0.10
0.09
0.10
0.06
ND
0.10
0.09
0.10
0.08
ND
0.10
0.09
ND
0.08
0.10
0.08
0.09
0.08
0.10
0.07
0.10
ND
0.10
ND
0.07
0.09
ND
0.09
0.08
0.08
ND
0.10
0.08
0.10
IN
0.10
ND
ND
0.07
0.09
ND
ND
0.08
0.08
0.09
0.08
PM10
WtdAM
(ng/m3)
25
23
32
23
29
IN
43
22
32
23
45
26
ND
51
30
34
35*
IN
33*
20
ND
30
28
22
IN
32
36
30
40
IN
ND
ND
20
ND
ND
49
ND
ND
ND
IN
19
29
IN
27
23*
ND
ND
IN
IN
ND
IN
22
IN
19
PM10
2nd Max
(Mg/m3)
57
53
72
49
56
31
102
57
84
45
117
72
ND
188
55
83
68*
IN
75*
38
ND
121
61
47
IN
68
99
66
114
60
ND
ND
81
ND
ND
198
ND
ND
ND
' 61
78
67
IN
47
44*
ND
ND
39
42
ND
32
51
36
35
S02
AM
(ppm)
0.003
0.011
0.004
ND
ND
ND
0.008
ND
0.010
0.006
0.011
0.003
ND
0.004
ND
0.005
0.004
IN
0.003
0.004
ND
0.004
0.005
ND
0.003
0.005
0.004
ND
0.012
ND
ND
ND
ND
ND
ND
0.006
ND
0.003
ND
0.010
ND
0.015
IN
ND
ND
ND
ND
0.002
0.003
ND
ND
0.003
ND
ND
S02
24-hr
(ppm)
0.013
0.037
0.011
ND
ND
ND
0.051
ND
0.040
0.020
0.057
0.011
ND
0.022
ND
0.019
0.029
IN
0.023
0.020
ND
0.018
0.022
ND
0.011
0.020
0.023
ND
0.073
ND
ND
ND
ND
ND
ND
0.027
ND
0.011
ND
0.068
ND
0.071
IN
ND
ND
ND
ND
0.014
0.019
ND
ND
0.017
ND
ND
APPENDIX A • DATA TABLES 149
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1998 (continued)
Metropolitan Statisticai Area 1990
Population
FORT SMITH, AR-OK
FORT WALTON BEACH, FL
FORT WAYNE, IN
FORT WORTH-ARLINGTON, TX
FRESNO, CA
QADSOEN, AL
GAINESVILLE, FL
GALVESTON-TEXAS CITY, TX
GARY, IN
GLENS FALLS, NY
GOLDSBORO, NC
GRAND FORKS, ND-MN
GRAND JUNCTION, CO
GRAND RAPIDS-MUSKEGON-HOLLAND, Ml
GREAT FALLS, MT
GREELEY, CO
GREEN BAY, Wl
GREENSBORO— WINSTON-SALEM— HIGH POINT
GREENVILLE, NC
GREENVILLE-SPARTANBURG-ANDERSON, SC
HAGERSTOWN, MD
HAMILTON-MIDDLETOWN, OH
HARRISBURG-LEBANON-CARLISLE, PA
HARTFORD, CT
HATTIESBURG. MS
HICKORY-MORGANTON-LENOIR, NC
HONOLULU, HI
HOUMA, LA
HOUSTON, TX
HUNTINGTON-ASHLAND, WV-KY-OH
HUNTSVILLE, AL
INDIANAPOLIS, IN
IOWA CITY, IA
JACKSON, Ml
JACKSON, MS
JACKSON, TN
JACKSONVILLE, FL
JACKSONVILLE, NC
JAMESTOWN, NY
JANESVILLE-BELOIT, Wl
JERSEY CITY, NJ
JOHNSON CITY-KINGSPORT-BRISTOL, TN-VA
JOHNSTOWN, PA
JONESBORO, AR
JOPLIN, MO
KALAMAZOO-BATTLE CREEK, Ml
KANKAKEE, IL
KANSAS CITY, MO-KS
KENOSHA, Wl
KILLEEN-TEMPLE, TX
KNOXVILLE, TN
KOKOMO, IN
LA CROSSE, Wl-MN
LAFAYETTE, LA
175,911
143,776
456,281
1,361,034
755,580
99,840
181,596
217,399
604,526
118,539
104,666
103,181
93,145
937,891
77,691
131,821
194,594
1,050,304
107,924
830,563
121,393
291,479
587,986
1,157,585
98,738
292,409
836,231
182,842
3,322,025
312,529
293,047
1,380,491
96,119
149,756
395,396
90,801
906,727
149,838
141,895
139,510
553,099
. 436,047
241,247
68,956
134,910
429,453
96,255
1,582,875
128,181
255,301
585,960
96,946
116,401
344,853
CO
8-hr
(ppm)
ND
ND
3
3
7
ND
ND
ND
5
ND
ND
ND
5
3
5
4
ND
5
ND
4
ND
ND
3
7
ND
ND
2
ND
5
7
3
3
ND
ND
4
ND
3
ND
ND
ND
6
3
3
ND
ND
ND
ND
5
ND
ND
4
ND
ND
ND
Pb NO2
QMax AM
(ug/m3) (ppm)
ND
ND
ND
• ND
0.00
ND
ND
ND
0.12
ND
ND
ND
ND
0.01
ND
ND
ND
ND
ND
0.02
ND
0.02
0.04
ND
ND
ND
ND
ND
ND
ND
ND
0.08s
ND
ND
ND
0.01
0.02
ND
ND
ND
ND
0.31
0.04
ND
ND
ND
ND
0.01
ND
ND
0
ND
ND
ND
ND
ND
ND
0.014
0.020
ND
ND
0.003
0.019
ND
ND
ND
ND
ND
ND
ND
ND
0.017
ND
0.017
ND
ND
0.019
0.02
ND
ND
0.004
ND
0.023
IN
ND
0.019
ND
ND
ND
ND
0.015
ND
ND
ND
0.027
0.017
0.015
ND
ND
ND
ND
0.013
ND
ND
ND
ND
ND
ND
03
1-hr
(ppm)
ND
ND
0.11
0.13
0.17
ND
0.11
0.17
0.12
ND
ND
ND
ND
0.12
ND
0.10
0.10
0.12
0.11
0.13
ND
0.12
0.12
0.13
ND
0.13
0.06
0.11
0.2
0.14
0.12
0.13
ND
ND
0.11
ND
0.1
ND
0.11
0.1
0.12
0.12
0.12
ND
ND
0.11
ND
0.13
0.13
ND
0.14
ND
ND
0.1
03
8-hr
(ppm)
ND
ND
0.09
o.fo
0.12
ND
0.09
0.11
0.09
ND
ND
ND
ND
0.10
ND
0.08
0.08
0.10
0.09
0.1
ND
0.09
0.1
0.1
ND
0.1
0.05
0.09
0.12
0.11
0.09
0.1
ND
ND
0.09
ND
0.1
ND
0.1
0.08
0.09
0.1
0.1
ND
ND
0.09
ND
0.1
0.09
ND
0.11
ND
ND
0.09
PM10 PM10 S02
WtdAM 2nd Max AM
(ug/m3) (ug/m3) (ppm)
25*
ND
34
26*
39
31
22
25*
32
ND
22
IN
20
20
ND
IN
ND
27
21
24
ND
36
22*
21
ND
23
16
ND
54*
35
22
30
ND
ND
28
IN
IN
22
23
ND
27*
25
IN
27*
ND
IN
ND
35
ND
ND
48
ND
ND
ND
49*
ND
66
50*
117
63
39
69*
136
ND
44
81
51
55
ND
39
ND
61
42
58
ND
74
65
66
ND
43
39
ND
129*
92
56
58
ND
ND
76
38
64
42
62
ND
63*
50
64
54*
ND
66
ND
64
ND
ND
174
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.004
0.009
ND
ND
ND
ND
0.002
0.003
ND
0.003
0.006.
ND
0.003
ND
0.007
0.006
0.005
ND
ND
0.002
ND
0.004
0.009
ND
' 0.006
ND
ND
0.002
ND
0.004
ND
0.007
ND
0.009
0.011
0.008
ND
ND
ND
ND
0.005
ND
ND
0.007
ND
ND
ND
S02
24-hr
(ppm)
ND
ND
ND
ND
ND
ND
ND
0.039
0.055
ND
ND
ND
ND
0.008
0.010
ND
0.011
0.023
ND
0.015
ND
0.022
0.021
0.019
ND
ND
0.009
ND
0.024
0.038
ND
0.024
ND
ND
0.008
ND
0.037
ND
0.032
ND
0.024
0.057
0.027
ND
ND
ND
ND
0.015
ND
ND
0.038
ND
ND
ND
150 DATA TABLES • APPENDIX A
-------
NATIONAL AIR'QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1998 (continued)
Metropolitan Statistical Area
LAFAYETTE, IN
LAKE CHARLES, LA
LAKELAND-WINTER HAVEN, FL
LANCASTER, PA
LANSING-EAST LANSING, Ml
LAREDO, TX
LAS CRUCES, NM
LAS VEGAS, NV-AZ
LAWRENCE, KS
LAWRENCE, MA-NH
LAWTON, OK
LEWISTON-AUBURN, ME
LEXINGTON, KY
LIMA, OH
LINCOLN, NE
LITTLE ROCK-NORTH LITTLE ROCK, AR
LONG VIEW-MARSH ALL, TX
LOS ANGELES-LONG BEACH, CA
LOUISVILLE, KY-IN
LOWELL, MA-NH
LUBBOCK, TX
LYNCHBURG, VA
MACON, GA
MADISON, Wl
MANCHESTER, NH
MANSFIELD, OH
MAYAGUEZ, PR
MCALLEN-EDINBURG-MISSION, TX
MEDFORD-ASHLAND, OR
MELBOURNE-TITUSVILLE-PALM BAY, FL
MEMPHIS, TN-AR-MS
MERCED, CA
MIAMI, FL
MIDDLESEX-SOMERSET-HUNTERDON, NJ
MILWAUKEE-WAUKESHA, Wl
MINNEAPOLIS-ST. PAUL, MN-WI
MISSOULA, MT
MOBILE, AL
MODESTO, CA
MONMOUTH-OCEAN, NJ
MONROE, LA
MONTGOMERY, AL
MUNCIE, IN
MYRTLE BEACH, SC
NAPLES, FL
NASHUA, NH
NASHVILLE, TN
NASSAU-SUFFOLK, NY
NEW BEDFORD, MA
NEW HAVEN-MERIDEN, CT
NEW LONDON-NORWICH, CT-RI
NEW ORLEANS, LA
NEW YORK, NY
NEWARK, NJ
1990
Population
161,572
168,134
405,382
422,822
432,674
133,239
135,510
852,737
81,798
353,232
111,486
93,679
405,936
154,340
213,641
513,117
193,801
8,863,164
948,829
280,578
222,636
193,928
290,909 ,.
367,085
50,000
174,007
237,143
383,545
146,389
398,978
1,007,306
178,403
1,937,094
1,019,835
1,432,149
2,538,834
78,687
476,923
370,522
986,327
142,191
292,517
119,659
144,053
152,099
168,233
985,026
2,609,212
175,641
530,180
290,734
1,285,270
8,546,846
1,915,928
CO
8-hr
(ppm)
ND
ND
ND
2
ND
4
4
10
ND
ND
2
ND
3
ND
6
5
ND
.12
6
3
ND
ND
ND
IN
ND
ND
ND
ND
5
ND
5
ND
3
3
3
7
ND
ND
5
3
ND
ND
ND
ND
ND
5
6
4
ND
3
ND
3
6
5
Pb
QMax
(Mg/rn3)
ND
ND
ND
0.04
ND
0.02
0.04
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.05
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.03
ND
2.02'
ND
ND
0.089
ND
0.1 4h
ND
ND
0
ND
ND
ND
0.91
ND
ND
ND
1.25i
ND
ND
ND
ND
0.11
0.14
ND
NO2
AM
(ppm)
ND
0.005
ND
0.015
ND._.
ND
0.01
ND
ND
ND
IN
ND
0.011
ND
ND
0.011
ND
0.043
0.023
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.029
0.011
0.015
0.019
0.021
0.026
ND
ND
0.018
ND
ND
ND
ND
ND
ND
0.015
0.013
0.022
ND
0.027
ND
0.02
0.04
0.042
03
1-hr
(ppm)
ND
0.12
0.11
0.12
-,,0,1
0.1
0.12
0.11
ND
0.1
0.09
ND
0.11
0.1
0.07
0.1
0.13
0.2
0.14
ND
ND
ND
0.14
0.09
ND
ND
ND
0.09
0.12
0.1
0.13
0.14
0.11
0.12
0.13
0.1
ND
0.11
0.15
0.14
0.09
0.12
ND
ND
ND
0.1
0.13
0.14
0.1
0.13
0.12
0.12
0.13
0.12
03
8-hr
(ppm)
ND
0.09
0.09
0.1
0.08
0.07
0.08
0.09
ND
0.08
0.09
ND
0.09
0.09
0.06
0.08
0.1
0.14
0.1
ND
ND
ND
0.11
0.08
ND
ND
ND
0.07
0.09
0.09
0.1
0.11
0.09
0.1
0.1
0.08
ND
0.1
0.11
0.1
0.08
0.09
ND
ND
ND
0.08
0.11
0.1
0.08
0.1
0.08
0.09
0.09
0.1
PM,o
WtdAM
(Mg/m3)
ND
ND
26
32*
ND
ND
32
45
ND
IN
IN
18
24
24
IN
34*
ND
41
27
ND
21*
IN
30
27
IN
24
ND
ND
20
17
28
ND
28
ND
30
IN
ND
31
31
ND
ND
27
ND
ND
IN
IN
33
20
16
27
18
29
56
40*
PM10
2nd Max
(ug/m3)
ND
ND
91
62
ND
ND
148
188
ND
39
IN
36
64
46
IN
98*
ND
78
58
ND
44*
IN
59
75
IN
66
ND
ND
70
44
65
ND
62
ND
63
73
ND
153
105
ND
ND
57
ND
ND
41
IN
87
46
42
71
41
61*
114
71*
S02
AM
(ppm)
ND
0.003
0.006
0.006
ND
ND
0.004
ND
ND
0.008
ND
0.004
0.006
0.003
ND
0.002
ND
0.004
0.009
ND
ND
ND
0.003
0.003
ND
ND
ND
ND
ND
ND
0.006
ND
0.001
0.005
0.004
0.005
ND
0.009
ND
ND
0.003
0.002
ND
ND
ND
0.007
0.006
0.007
ND
0,006
0.004
0.004
0.012
0.007
S02
24-hr
(ppm)
ND
0.012
0.027
0.02
ND
ND
0.019
ND
ND
0.031
ND
0.019
0.023
0.017
ND
0.006
ND
0.012
0.045
ND
ND
ND
0.019
0.016
ND
ND
ND
ND
ND
ND
0.041
ND
0.004
0.018
0.022
0.019
ND
0.073
ND
ND
0.012
0.01
ND
ND
ND
0.027
0.046
0.033
ND
0.031
0.018
0.026
0.038
0.025
APPENDIX A • DATA TABLES 151
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1998 (continued)
Metropolitan Statistical Area
NEWBURGH, NY-PA
NORFOLK-VIRGINIA BEACH-NEWPORT NEWS.VA
OAKLAND, CA
OCALA, FL
ODESSA-MIDLAND, TX
OKLAHOMA CITY, OK
OLYMPIA, WA
OMAHA, NE-IA
ORANGE COUNTY, CA
ORLANDO, FL
OWENSBORO, KY
PANAMA CITY, FL
PARKERSBURG-MARIETTA, WV-OH
PENSACOLA, FL
PEORIA-PEKIN, IL
PHILADELPHIA, PA-NJ
PHOENIX-MESA, AZ
PINE BLUFF, AR
PITTSBURGH, PA
PITTSFIELD, MA
POCATELLO, ID
PONCE, PR
PORTLAND, ME
PORTLAND-VANCOUVER, OR-WA
PORTSMOUTH-ROCHESTER, NH-ME
PROVIDENCE-FALL RIVER-WARWICK, RI-MA
PROVO-OREM, UT
PUEBLO. CO
PUNTA GORDA, FL
RACINE, Wl
RALEIGH-DURHAM-CHAPEL HILL, NC
RAPID CITY, SO
READING, PA
REDDING, CA
RENO, NV
RICHLAND-KENNEWICK-PASCO, WA
RICHMOND-PETERSBURG, VA
RIVERSIDE-SAN BERNARDINO, CA
ROANOKE, VA
ROCHESTER, MN
ROCHESTER, NY
ROCKFORD, IL
ROCKY MOUNT, NC
SACRAMENTO, CA
SAGINAW-BAY CITY-MIDLAND, Ml
ST. CLOUD, MN
ST. JOSEPH, MO
ST. LOUIS, MO-IL
SALEM, OR
SALINAS, CA
SALT LAKE CITY-OGDEN, UT
SAN ANGELO, TX
SAN ANTONIO, TX
SAN DIEGO, CA
1990
Population
335,613
1,443,244
2,082,914
194,833
255,545
958,839
161,238
639,580
2,410,556
1,224,852
87,189
126,994
149,169
344,406
339,172
4,922,175
2,238,480
85,487
2,384,81 1
88,695
66,026
3,442,660
221,095
1,515,452
223,271
1,134,350
263,590
123,051
110,975
175,034
855,545
81,343
336,523
147,036
254,667
150,033
865,640
2,588,793
224,477
106,470
1,062,470
329,676
133,235
1,340,010
399,320
190,921
83,083
1,836,302
278,024
355,660
1,072,227
98,458
1,324,749
2,498,016
CO
8-hr
(ppm)
ND
6
4
ND
ND
4
5
8
7
4
1
ND
ND
ND
6
5
8
ND
4
ND
ND
ND
ND
6
ND
5
6
ND
ND
3
5
ND
3
ND
7
ND
2
5
4
ND
3
4
ND
6
ND
4
ND
6
5
2
8
ND
5
5
Pb
QMax
(Mg/m3)
0.1 4k
ND
0.01
ND
ND
ND
ND
0.25'
ND
ND
ND
ND
ND
ND
0.02
1.64m
ND
ND
0.06
ND
ND
ND
ND
0.3
ND
ND
ND
ND
ND
ND
ND
ND
0.71"
ND
ND
ND
0.01
0.05
ND
ND
ND
0.04
ND
0.01
ND
ND
ND
11.6°
ND
ND
0.09
ND
ND
0.01
NO2
AM
(ppm)
ND
0.019
0.02
ND
ND
0.012
ND
ND
0.034
0.011
0.013
ND
ND
ND
ND
0.034
0.035
ND
0.031
ND
IN
ND
ND
0.012
0.012
0.025
0.024
ND
ND
ND
ND
ND
0.021
ND
ND
ND
0.021
0.036
0.014
ND
ND
ND
ND
0.021
ND
ND
ND
0.026
ND
0.01
0.027
ND
0.024
0.023
03
1-hr
(ppm)
0.1
0.11
0.14
0.1
ND
0.11
0.11
0.09
0.16
0.12
0.11
ND
0.12
0.13
0.09
0.13
0.11
ND
0.13
0.08
ND
ND
0.12
0.14
0.12
0.11
0.11
ND
ND
0.12
0.12
ND
0.11
0.14
0.09
ND
0.13
0.24
0.13
ND
0.1
0.09
0.11
0.15
ND
ND
ND
0.14
0.11
0.09
0.12
ND
0.12
0.14
03
8-hr
(ppm)
0.09
0.09
0.1
0.08
ND
0.09
0.07
0.07
0.09
0.1
0.09
ND
0.09
0.1
0.08
0.1
0.09
ND
0.11
IN
ND
ND
0.09
0.08
0.09
0.09
0.09
ND
ND
0.08
0.11 .
ND
0.09
0.11
0.08
ND
0.1
0.18
0.1
ND
0.09
0.07
0.09
0.12
ND
ND
ND
0.1
0.08
0.07
0.1
ND
0.09
0.11
PM»
WtdAM
(|jg/m3)
ND
24
22
ND
ND
IN
IN
39
36
28
25
IN
29
22
26
31*
81
24*
41
ND
27
IN
IN
29
IN
18
28
IN
ND
ND
25
31
IN
23
46
IN
23
50
33
IN
IN
24
22
27
ND
ND
IN
46
ND
27
33
ND
27*
43
PM10
2nd Max
(Mg/m3)
ND
49
59
ND
ND
IN
46
106
65
63
57
52
68
50
54
105
208
47*
130
ND
92
IN
67
59
IN
59
75
52
ND
ND
62
110
51
54
125
90
53
114
64
36
50
52
43
99
ND
ND
124
116
ND
50
99
ND
61*
88
S02
AM
(ppm)
ND
0.006
0.003
ND
ND
0.003
ND
0.002
0.002
0.002
0.007
ND
0.013
0.004
0.007
0.01
0.008
ND
0.016
ND
0.006
ND
0.005
ND
0.004
0.007
ND
ND
ND
ND
0.005
ND
0.009
ND
ND
ND
0.006
0.002
0.003
ND
0.01
ND
ND
0.003
ND
ND
0.007
0.009
ND
ND
0.004
ND
ND
0.003
S02
24-hr
(ppm)
ND
0.021
0.014
ND
ND
0.007
ND
0.032
0.005
0.007
0.023
ND
0.089
0.024
0.045
0.035
0.027
ND
0.094
ND
0.034
ND
0.025
ND
0.016
0.027
ND
ND
ND
ND
0.009
ND
0.025
ND
ND
ND
0.019
0.009
0.009
ND
0.054
ND
ND
0.015
ND
ND
0.121
0.069
ND
ND
0.01
ND
ND
0.016
152 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1998 (continued)
Metropolitan Statistical Area
SAN FRANCISCO, CA
SAN JOSE, CA
SAN JUAN-BAYAMON, PR
SAN LUIS OBISPO-ATASCADERO-PASO ROBLE
SANTA BARBARA-SANTA MARIA-LOMPOC, CA
SANTA CRUZ-WATSONVILLE, CA
SANTA FE, NM
SANTA ROSA, CA
SARASOTA-BRADENTON, FL
SAVANNAH, GA
SCRANTON-WILKES-BARRE-HAZLETON, PA
SEATTLE-BELLEVUE-EVERETT, WA
SHARON, PA
SHEBOYGAN, Wl
SHERMAN-DENISON, TX
SHREVEPORT-BOSSIER CITY, LA
SIOUX CITY, IA-NE
SIOUX FALLS, SD
SOUTH BEND, IN
SPOKANE, WA
SPRINGFIELD, IL
SPRINGFIELD, MO
SPRINGFIELD, MA
STAMFORD-NORWALK, CT
STATE COLLEGE, PA
STEUBENVILLE-WEIRTON, OH-WV
STOCKTON-LODI, CA
SUMTER, SC
SYRACUSE, NY
TACOMA, WA
TALLAHASSEE, FL
TAMPA-ST. PETERSBURG-CLEARWATER, FL
TERRE HAUTE, IN
TEXARKANA, TX-TEXARKANA, AR
TOLEDO, OH
TOPEKA, KS
TRENTON, NJ
TUSCON, AZ
TULSA, OK
TUSCALOOSA, AL
TYLER, TX
UTICA-ROME, NY
VALLEJO-FAIRFIELD-NAPA, CA
VENTURA, CA
VICTORIA, TX
VINELAND-MILLVILLE-BRIDGETON, NJ
VISALIA-TULARE-PORTERVILLE, CA
WACO, TX
WASHINGTON, DC-MD-VA-WV
WATERBURY, CT
WATERLOO-CEDAR FALLS, IA
WAUSAU, Wl
WEST PALM BEACH-BOCA RATON, FL
WHEELING, WV-OH
1990
Population
1,603,678
1,497,577
1,836,302
217,162
369,608
229,734
117,043
388,222
489,483
258,060
638,466
2,033,156
121,003
103,877
95,021
376,330
115,018
139,236
247,052
361,364
189,550
264,346
587,884
329,935
123,786
142,523
480,628
102,637
742,177
586,203
233,598
2,067,959
147,585
120,132
614,128
160,976
325,824
666,880
708,954
150,522
151,309
316,633
451,186
669,016
74,361
138,053
311,921
189,123
4,223,485
221,629
123,798
115,400
863,518
159,301
CO
8-hr
(ppm)
4
6
6
2
4
1
2
3
6
ND
3
6
ND
ND
ND
ND
ND
ND
ND
7
2
4
5
4
ND
13
5
ND
3
6
ND
4
ND
. ND
2
ND
ND
4
5
ND
ND
ND
5
3
ND
ND
4
ND
5
ND
ND
ND
3
4
Pb
QMax
(ug/m3)
0.01
0.01
ND
ND
0
ND
ND
ND
ND
ND
ND
2.03P
0.04
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0
0.01
ND
ND
ND
0.511
0.02
ND
0.35
ND
ND
ND
ND
ND
ND
ND
ND
0
ND
ND
ND
ND
0.03r
0.02
ND
ND
0
ND
NO2
AM
(ppm)
0.02
0.025
IN
0.011
0.021
0.004
ND
0.015
ND
ND
0.016
0.02
ND
ND
ND
ND
ND
ND
0.012
ND
ND
0.012
0.02
ND
ND
0.015
0.023
ND
ND
ND
ND
0.012
ND
ND
ND
ND
0.015
0.017
0.015
ND
ND
ND
0.014
0.019
ND
ND
0.017
ND
0.027
ND
ND
ND
0.012
ND
03
1-hr
(ppm)
0.07
0.14
0.04
0.11
0.12
0.09
ND
0.1
0.12
0.1
0.11
0.14
0.12
0.13
ND
0.11
ND
ND
0.12
0.08
0.09
0.09
0.12
0.11
0.11
0.1
0.12
ND
0.09
0.13
0.09
0.13
0.1
ND
0.11
ND
0.11
0.09
0.12
ND
0.11
0.09
0.13
0.14
0.1
0.12
0.14
ND
0.13
ND
ND
0.1
0.11
0.1
03
8-hr
(ppm)
0.05
0.09
0.04
0.1
0.09
0.07
ND
0.09
0.09
0.08
0.09
0.09
0.11
0.1
ND
0.09
ND
ND
0.1
0.07
0.08
0.07
0.09
0.09
0.09
0.09
0.09
ND
0.08
0.09
0.08
0.1
0.08
ND
0.09
ND
0.1
0.08
0.09
ND
0.09
0.08
0.1
0.11
0.08
0.1
0.11
ND
0.11
ND
ND
0.08
0.08
0.09
PM10
Wtd AM
(ug/m3)
22
25
36
22
25
29
14
18
23
26
29*
15
28*
ND
ND
26*
28
IN
24
26
25
18
28
28
ND
35
29
ND
27
18
IN
32
28
23*
IN
IN
ND
39
25*
28
ND
13
17
24 -
ND
ND
40
ND
28
21
IN
24
22
25
PM10
2nd Max
(ug/m3)
46
60
99
67
55
67
28
38
82
79
54
67
75*
ND
ND
57*
56
53
45
87
65
43
62
50
ND
119
95
ND
62
62
63
105
52
53*
51
67
ND
78
56*
53
ND
45
46
52
ND
ND
123
ND
57
60
52
57
52
56
S02
AM
(ppm)
0.002
ND
0.005
0.005
0.002
0.001
ND
ND
0.003
0.003
0.006
0.006
0.007
ND
ND
0.002
ND
ND
ND
ND
0.007
0.004
0.005
0.006
ND
0.016
ND
ND
0.002
0.006
ND
0.008
0.01
IN
0.004
ND
ND
0.002
0.019
ND
ND
0.001
0.002
0.003
ND
0.004
ND
ND
0.01
0.006
ND
0.003
0.001
0.015
S02
24-hr
(ppm)
0.006
ND
0.019
0.03
0.002
0.003
ND
ND
0.019
0.027
0.026
0.016
0.029
ND
ND
0.01
ND
ND
ND
ND
0.061
0.042
0.026
0.025
ND
0.067
ND
ND
0.011
0.02
ND
0.048
0.032
IN
0.021
ND
ND
0.004
0.059
ND
ND
0.005
0.005
0.011
ND
0.012
ND
ND
0.025
0.021
ND
0.031
0.004
0.061
APPENDIX A
DATA TABLES
153
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1998 (continued)
Metropolitan Statistical Area
NO,
PM10 PM10
SO,
CO Pb
1990 8-hr QMax AM" 1-hr 8-hr Wtd AM 2nd Max AM
Population (ppm) (ug/m3) (ppm) (ppm) (ppm) (ug/m3) (ug/m3) (ppm)
S02
24-hr
(ppm)
WICHITA, KS
WICHITA FALLS, TX
WILLIAMSPORT, PA
WILMINGTON-NEWARK, DE-MD
WILMINGTON, NC
WORCESTER, MA-CT
YAKIMA, WA
YOLO, CA
YORK, PA
YOUNGSTOWN-WARREN, OH
YUBA CITY, CA
YUMA, AZ
485,270
130,351
118,710
513,293
171,269
478,384
188,823
141,092
339,574
600,859
122,643
106,895
ND
ND
3
IN
4
5
1
2
ND
4
ND
0.01
ND
ND
ND
ND
ND
ND
ND
0.05
ND
ND
ND
ND
ND
ND
0.016
ND
0.019
ND
0.011
0.019
0.015
0.013
ND
0.1
ND
0.1
0.13
0.1
0.12
ND
0.11
0.11
0.12
0.1
0.1
0.08
ND
0.08
0.1
0.09
0.1
ND
0.09
0.1
0.1
0.09
0.09
26
ND
24*
28*
IN
20
26
27
29*
39
23
ND
75
ND
ND
76
40
50
81
73
60
88
54
ND
ND
ND
0.005
0.008
0.007
0.005
ND
ND
0.008
0.009
ND
ND
ND
ND
0.021
0.044
0.026
0.017
ND
ND
0.023
0.049
ND
ND
CO — Highest second maximum non-overlapping 8-hour concentration (Applicable NAAQS is 9 ppm)
Pb - Highest quarterly maximum concentration (Applicable NAAQS is 1.5 ijg/m3)
NO, - Highest arithmetic mean concentration (Applicable NAAQS is 0.053 ppm)
O3 (1-lx) - Highest second daily maximum 1-hour concentration (Applicable NAAQS is 0.12 ppm)
O, (8-h») - Highest fourth daily maximum 8-hour concentration (Applicable NAAQS is 0.08 ppm)
PMIO — Highest weighted annual mean concentration (Applicable NAAQS is 50 fjg/m3)
— Highest second maximum 24-hour concentration (Applicable NAAQS is 150 pg/m3)
SOj - Highest annual mean concentration (Applicable NAAQS is 0.03 ppm)
— Highest second maximum 24-hour concentration (Applicable NAAQS is 0.14 ppm)
ND - Indicates data not available
IN — Indicates Insufficient data to calculate summary statistic
Wtd - Weighted
AM - Annual mean
ug/m3 — Units are micrograms per cubic meter
PPM - Units are parts per million
Data from exceptional events not included.
C) -
These PM,0 statistics were converted from local temperature and pressure to standard temperature and pressure to ensure all PM,0 data
in this table reflect standard conditions.
(a)
(b)
(c)
(d)
(e)
(0
(9)
«h)
0)
(I)
(k)
(I)
(m)
(n)
(o)
(P)
(q)
(r)
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an Industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized impact from an industrial source
Localized Impact from an industrial source
Localized impact from an industrial source
in Cleveland, OH. Highest population-oriented site in MSA is in Cleveland, OH (0.05 pg/m3).
in Columbus, GA.
in Columbus, OH. Highest population-oriented site in MSA is in Columbus, OH (0.01 ug/m3).
in Frisco, TX. Highest population-oriented site in MSA is in Midlothian, TX (0.30 ug/m3).
in Indianapolis, IN.
in Memphis, TN. Highest population-oriented site in MSA is in Memphis, TN (0.03 ug/m3).
in New Brunswick, NJ.
in Eagan, MN. Highest population-oriented site in MSA is in Richfield, MN (0.02 ug/m3).
in Muncie, IN.
in Williamson Co., TN.
in Middletown, NY. Highest population-oriented site in MSA is in Middletown, NY (0.03 ug/m3).
in Omaha, NE.
in Philadelphia, PA. Highest population-oriented site in MSA is in Philadelphia, PA (0.38 ug/m3).
in Berks Co., PA.
in Herculaneum, MO. Highest population-oriented site in MSA is in Wood River, IL (0.14 ug/m3).
in Seattle, WA. This facility has been shut down.
in Tampa, FL. Highest population-oriented site in MSA is in Tampa, FL (0.23 ug/m3).
in Lorton, VA. Highest population-oriented site in MSA is in Washington, DC (0.02 ug/m3).
Note: The reader is cautioned that this summary is not adequate in itself to numerically rank MSAs according to their air quality. The monitoring
data represent the quality of air in the vicinity of the monitoring site but may not necessarily represent urban-wide air quality.
154 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998
Metropolitan Statistical Area
AKRON, OH
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
ALBANY-SCHENECTADY-TROY, NY
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
ALBUQUERQUE, NM
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ALEXANDRIA, LA
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ALLENTOWN-BETHLEHEM-EASTON, PA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
ALTOONA, PA
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
ANCHORAGE, AK
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ANN ARBOR, Ml
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
ANNISTON, AL
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ASHEVILLE, NC
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ATLANTA, GA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
ATLANTIC-CAPE MAY, NJ
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
NS
NS
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
NS
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
NS
DOWN
UP
UP
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
NS
NS
UP
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
NS
#Trend
Sites
1
2
2
2
1
1
1
1
1
1
3
3
5
5
1
1
6
1
7
7
8
8
1
1
2
1
1
3
3
3
3
1
1
1
1
1
1
3
3
1
1
1
1
1
1
1
1
1
2
2
2
2
3
3
2
2
1
1
1
1
1989
5.2
0.10
0.10
0.13
34
52
0.015
0.053
5.7
0.04
0.08
0.10
21
36
0.005
0.022
6.6
0.019
0.07
0.09
33
52
23
38
4.8
0.78
0.020
0.09
0.10
0.009
0.040
1.7
0.015
0.07
0.10
0.011
0.059
26
47
0.08
0.10
28
46
0.07
0.08
29
47
6.2
0.04
0.023
0.09
0.12
33
52
0.007
0.043
0.10
0.12
0.005
0.029
1990
5.7
0.04
0.10
0.11
26
49
0.015
0.061
6.2
0.13
0.08
0.10
21
36
0.006
0.028
6.1
0.018
0.07
0.09
24
39
23
38
5.3
0.40
0.017
0.09
0.11
0.009
0.039
1.7
0.015
0.07
0.10
0.011
0.062
31
63
0.08
0.09
28
46
0.07
0.09
25
41
5.4
0.03
0.021
0.09
0.14
39
68
0.007
0.026
0.10
0.16
0.004
0.012
1991
3.3
0.06
0.09
0.12
28
51
0.015
0.051
5.4
0.04
0.08
0.10
21
36
0.007
0.030
5.5
0.004
0.07
0.08
22
37
22
37
5.3
0.46
0.018
0.09
0.12
0.008
0.036
1.7
0.015
0.08
0.11
0.011
0.044
30
57
0.08
0.11
29
46
0.07
0.08
24
41
6.5
0.04
0.020
0.12
0.12
32
53
0.006
0.032
0.11
0.14
0.004
0.011
1992
4.1
0.05
0.10
0.11
27
44
0.013
0.064
4.7
0.03
0.08
0.10
21
34
0.006
0.022
5.0
0.021
0.07
0.09
23
34
25
40
3.8
0.28
0.018
0.10
0.10
0.007
0.031
2.8
0.014
0.09
0.10
0.009
0.046
31
61
0.09
0.10
25
37
0.06
0.08
23
40
5.1
0.03
0.020
0.09
0.13
28
46
0.006
0.028
0.11
0.12
0.003
0.016
1993
3.1
0.06
0.09
0.11
25
49
0.015
0.056
3.8
0.03
0.09
0.10
20
34
0.006
0.026
5.1
0.024
0.07
0.08
23
36
21
36
3.6
0.18
0.020
0.08
0.11
0.007
0.028
2.0
0.015
0.08
0.10
0.009
0.052
28
55
0.08
0.10
25
38
0.06
0.08
22
43
4.9
0.02
0.020
0.09
0.14
29
47
0.006
0.036
0.09
0.12
0.003
0.014
1994
5.3
0.06
0.09
0.10
28
51
0.012
0.042
5.2
0.04
0.08
0.10
21
40
0.006
0.027
4.9
0.023
0.06
0.08
22
36
23
38
6.6
0.13
0.021
0.08
0.11
0.009
0.045
2.4
0.015
0.09
0.11
0.010
0.058
27
50
0.08
0.09
24
40
0.07
0.08
19
30
5.3
0.03
0.018
0.11
0.12
27
43
0.004
0.023
0.09
0.10
0.003
0.019
1995
3.3
0.03
0.09
0.12
26
48
0.009
0.046
4.3
0.04
0.08
0.10
18
32
0.005
0.016
5.0
0.018
0.07
0.08
24
39
21
37
4.7
0.07
0.018
0.08
0.11
0.007
0.027
1.7
0.013
0.09
0.11
0.008
0.037
26
51
0.08
0.11
23
40
0.07
0.09
18
28
4.5
0.05
0.017
0.10
0.14
28
45
0.004
0.018
0.08
0.12
0.003
0.011
1996 1997
3.4 3.2
0.04 0.04
0.09 0.09
0.11 0.10
25 24
35 39
0.010 0.012
0.042 0.072
3.7 4.5
0.03 0.03
0.08 0.07
0.09 0.10
19 20
29 32
0.005 0.004
0.021 0.017
4.3 3.7
0.022 0.019
0.07 0.07
0.08 0.08
24 21
38 33
19 23
27 32
3.2 2.9
0.08 0.09
0.018 0.016
0.10 0.09
0.11 0.11
0.007 0.009
0.030 0.030
1.9 1.5
0.013 0.014
0.09 0.08
0.10 0.11
0.008 0.010
0.033 0.046
25 25
48 51
0.08 0.09
0.10 0.10
19 23
27 42
0.08 0.07
0.08 0.09
19 21
29 38
3.7 4.3
0.03 0.02
0.021 0.020
0.11 0.10
0.13 0.13
27 28
41 49
0.004 0.004
0.018 0.023
0.10 0.10
0.11 0.13
0.003 0.003
0.014 0.011
1998
2.6
0.02
0.09
0.11
24
39
0.010
0.044
4.4
0.03
0.08
0.10
20
36
0.003
0.013
3.7
0.016
0.07
0.09
21
32
23
32
3.0
0.12
0.016
0.10
0.11
0.010
0.032
1.2
0.013
0.10
0.11
0.008
0.032
20
37
0.09
0.10
26
41
0.08
0.11
20
36
4.1
0.02
0.019
0.10
0.14
28
50
0.004
0.017
0.11
0.12
0.003
0.010
APPENDIX A • DATA TABLES 155
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
AUQUSTA-AIKEN, GA-SC
LEAD MAX QUARTERLY MEAN
O« 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
• PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
AUSTIN-SAN MARCOS, TX
CO 2ND MAX 8-HOUR
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PMto WEIGHTED ANNUAL MEAN
90TH PERCENTILE
BAKERSFIELD, CA
NO. ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
BALTIMORE, MD
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO* ARITHMETIC MEAN
O. 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PMla WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOa ARITHMETIC MEAN
2ND MAX 24-HOUR
BANGOR. ME
PM|0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
BATON ROUGE, LA
LEAD MAX QUARTERLY MEAN
NO* ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM18 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOj ARITHMETIC MEAN
2ND MAX 24-HOUR
BEAUMONT-PORT ARTHUR, TX
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOj ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
BELLINGHAM, WA
Oj 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
BERGEN-PASSAIC, NJ
CO 2ND MAX 8-HOUR
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM18 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
BILLINGS, MT
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
B1LOX1-GULFPORT-PASCAGOULA, MS
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
NS
NS
NS
NS
NS
UP
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
NS
#Trend
Sites
1
3
3
1
1
1
1
2
2
2
2
4
5
5
4
4
1
1
3
1
1
7
7
5
5
2
2
1
1
3
1
3
3
2
2
1
1
1
1
2
3
3
2
2
1
1
1
1
2
1
1
1
3
3
2
2
4
4
1
1
1
1
1989
0.03
0.08
0.10
21
39
4.2
0.017
0.08
0.11
25
37
0.017
0.11
0.13
46
83
0.004
0.014
6.5
0.11
0.035
0.09
0.12
36
60
0.012
0.042
26
42
0.08
0.015
0.09
0.14
28
44
0.007
0.056
2.0
0.02
0.010
0.09
0.13
0.008
0.088
0.06
0.08
0.006
0.018
7.5
0.035
0.10
0.12
35
61
0.011
0.045
0.018
0.078
0.08
0.12
0.006
0.029
1990
0.02
0.08
0.10
22
36
5.9
0.017
0.08
0.11
21
34
0.017
0.11
0.13
47
89
0.004
0.011
7.1
0.06
0.034
0.09
0.13
33
52
0.008
0.030
21
33
0.05
0.014
0.09
0.15
28
43
0.005
0.022
2.3
0.02
0.009
0.09
0.12
0.009
0.042
0.06
0.08
0.007
0.028
6.8
0.031
0.10
0.13
37
59
0.010
0.041
0.016
0.066
0.08
0.12
0.007
0.037
1991
0.01
0.09
0.10
23
35
3.4
0.016
0.08
0.10
24
35
0.017
0.10
0.13
54
91
0.002
0.010
6.4
0.04
0.033
0.10
0.14
36
58
0.009
0.030
25
41
0.03
0.015
0.11
0.13
28
49
0.009
0.036
2.3
0.03
0.010
0.09
0.13
0.008
0.059
0.06
0.07
0.006
0.021
6.6
0.031
0.10
0.14
39
62
0.010
0.035
0.016
0.069
0.08
0.12
0.006
0.034
1992
0.01
0.07
0.09
22
32
3.7
0.017
0.08
0.09
23
34
0.016
0.11
0.12
38
62
0.003
0.010
5.5
0.04
0.031
0.11
0.12
30
47
0.009
6.027
22
32
0.10
0.016
0.09
0.11
27
37
0.008
0.033
2.4
0.02
0.011
0.10
0.13
0.006
0.044
0.06
0.07
0.007
0.022
4.5
0.030
0.10
0.10
33
50
0.009
0.040
0.020
0.081
0.08
0.11
0.006
0.020
1993
0.01
0.07
0.10
22
35
3.0
0.017
0.08
0.09
19
35
0.015
0.10
0.13
33
60
0.002
0.010
5.4
0.04
0.033
0.09
0.13
29
51
0.008
0.026
22
34
0.03
0.012
0.08
0.11
22
35
0.006
0.021
3.3
0.02
0.009
0.09
0.12
0.006
0.047
0.06
0.08
0.006
0.017
5.2
0.029
0.08
0.11
31
51
0.008
0.026
0.021
0.104
0.09
0.10
0.004
0.029
1994
0.01
0.08
0.09
21
35
5.8
0.018
0.08
0.10
20
34
0.015
0.11
0.13
30
47
0.003
0.007
5.8
0.03 •
0.032 '
0.11
0.13
30
53
0.009
0.030
22
35
0.04
0.016
0.08
0.12
26
41
0.008
0.025
2.0
0.02
0.010
0.09
0.11
0.006
0.039
0.06
0.08
0.007
0.019
6.2
0.031
0.08
0.11
35
57
0.007
0.037
0.015
0.066
0.08
0.12
0.003
0.022
1995
0.01
0.08
0.10
19
29
3.5
0.021
0.08
0.11
22
35
0.013
0.10
0.13
33
62
0.003
0.008
4.7
0.03
0.026
0.10
0.14
29
48
0.006
0.022
20
32
0.05
0.016
0.08
0.12
24
38
0.006
0.034
1.7
0.02
0.010
0.08
0.13
0.005
0.025
0.06
0.08
0.006
0.018
4.9
0.029
0.09
0.12
31
49
0.005
0.027
0.013
0.059
0.09
0.11
0.003
0.024
1996 1997
0.00 0.01
0.08 0.08
0.10 0.11
19 21
29 31
3.2 3.2
0.018 0.018
0.09 0.08
0.10 0.09
19 19
26 26
0.013 0.013
0.11 0.11
0.14 0.12
28 28
47 45
0.003 0.003
0.009 0.009
3.6 4.6
0.03 0.01
0.027 0.026
0.10 0.09
0.12 0.14
27 28
43 46
0.007 0.008
0.026 0.025
19 21
27 33
0.03 0.04
0.015 0.013
0.09 0.09
0.11 0.12
24 27
35 44
0.006 0.006
0.024 0.027
2.1 2.1
0.02 0.02
0.010 0.010
0.10 0.08
0.12 0.14
0.005 0.006
0.041 0.037
0.05 0.06
0.08 0.07
0.005 0.005
0.013 0.012
3.8 4.9
0.028 0.028
0.10 0.08
0.11 0.12
31 31
48 49
0.006 0.005
0.022 0.021
0.009 0.007
0.056 0.032
0.09 0.08
0.10 0.09
0.003 0.002
0.043 0.025
1998
0.02
0.08
0.12
22
38
3.2
0.018
0.07
0.10
19
26
0.013
0.10
0.13
25
46
0.003
0.009
4.1
0.01
0.026
0.11
0.12
29
48
0.007
0.021
18
34
0.05
0.015
0.09
0.13
27
44
0.007
0.036
2.1
0.02
0.008
0.09
0.12
0.005
0.033
0.05
0.07
0.005
0.015
3.7
0.028
0.10
0.12
31
49
0.005
0.021
0.006
0.025
0.08
0.11
0.003
0.022
156 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, A998
Table A-14.
Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
BIRMINGHAM, AL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
BOISE CITY, ID
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
BOSTON, MA-NH
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
BOULDER-LONGMONT, CO
CO 2ND MAX 8-HOUR
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
BRAZORIA.TX
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
BRIDGEPORT, CT
CO 2ND MAX 8-HOUR
N02 ' ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
BROCKTON, MA
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
BROWNSVILLE-HARLINGEN-SAN BENITO, TX
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
BUFFALO-NIAGARA FALLS, NY
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
BURLINGTON, VT
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
CANTON-MASSILLON, OH
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
DOWN
NS
NS
NS
NS
DOWN
NS
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
#Trend 1989
Sites
3
1
6
6
6
6
1
1
3
3
4
3
4
4
7
7
11
11
2
1
1
2
2
1
1
1
1
2
2
1
1
1
1
1
1
1
1
3
1
2
2
2
12
12
4
4
1
1
2
2
1
1
2
2
2
2
1
1
7.5
0.13
0.08
0.10
31
50
0.008
0.025
42
85
5.0
0.031
0.09
0.12
26
41
0.010
0.041
6.6
0.08
0.11
29
51
0.10
0.15
5.2
0.026
0.11
0.16
27
47
0.014
0.051
0.09
0.13
22
36
4.4
0.04
0.022
0.08
0.10
25
47
0.012
0.051
3.7
0.019
25
38
0.007
0.031
0.09
0.11
35
64
0.012
0.041
1990
6.9
0.14
0.08
0.12
35
57
0.008
0.025
29
55
5.6
0.029
0.09
0.10
25
40
0.009
0.038
5.7
0.08
0.10
23
39
0.10
0.15
5.0
0.026
0.11
0.15
25
41
0.013
0.050
0.09
0.12
22
36
3.4
0.03
0.020
0.08
0.11
19
35
0.011
0.054
4.6
0.018
24
38
0.008
0.021
0.09
0.10
30
52
0.011
0.036
1991
7.1
0.09
0.09
0.10
32
54
0.007
0.020
35
74
4.1
0.031
0.08
0.13
24
39
0.009
0.030
5.7
0.07
0.10
23
44
0.10
0.13
5.5
0.025
0.10
0.15
28
49
0.012
0.044
0.09
0.15
24
36
3.1
0.03
0.018
0.09
0.11
25
48
0.012
0.062
3.8
0.017
23
37
0.008
0.022
0.09
0.11
31
50
0.010
0.037
«3SBBa^w^,rswin=™^^
1992 1993 1994 1995 1996 1997 1998
6.9
0.08
0.08
0.11
29
45
0.007
0.027
34
58
4.7
0.029
0.09
0.11
22
35
0.009
0.037
5.9
0.08
0.09
23
35
0.09
0.13
4.7
0.024
0.11
0.12
22
37
0.011
0.040
0.10
0.11
24
36
4.6
0.03
0.018
0.09
0.11
21
33
0.011
0.058
3.9
0.016
23
39
0.003
0.013
0.10
0.09
28
45
0.010
0.040
6.9
0.07
0.08
0.11
27
42
0.009
0.050
37
64
4.0
0.030
0.09
0.11'
22
35
0.009
0.032
5.3
0.07
0.10
24
44
0.10
0.13
3.7
0.024
0.08
0.16
21
43
0.010
0.035
0.09
0.11
22
45
3.4
0.05
0.017
0.08
0.09
19
35
0.010
0.042
3.9
0.017
21
36
0.003
0.011
0.08
0.10
26
45
0.010
0.046
6.6
0.07
0.08
0.10
25
38
0.007
0.037
35
63
4.9
0.030
0.09
0.11
23
38
0.008
0.032
4.5
0.07
0.09
19
29
0.09
0.11
5.8
0.026
0.10
0.15
26
44
0.010
0.049
0.09
0.12
23
36
3.2
0.05
0.019
0.08
0.09
19
34
0.010
0.039
3.9
0.017
21
35
0.003
0.013
0.09
0.10
28
50
0.009
0.052
6.3
0.09
0.08
0.12
26
42
0.006
0.016
30
50
3.6
0.027
0.08
0.11
21
34
0.006
0.023
4.2
0.07
0.10
16
27
0.09
0.15
4.9
0.024
0.09
0.13
22
37
0.007
0.028
0.10
0.13
21
35
2.6
0.03
0.019
0.08
0.10
18
34
0.008
0.040
2.5
0.017
20
35
0.002
0.006
0.08
0.10
29
52
0.006
0.033
5.3
0.13
0.10
0.13
25
38
0.004
0.015
28
49
3.6
0.028
0.09
0.09
23
39
0.006
0.025
4.0
0.07
0.09
17
27
0.11
0.11
3.0
0.024
0.10
0.11
21
32
0.006
0.023
0.10
0.10
19
28
2.9
0.03
0.019
0.09
0.10
19
29
0.007
0.034
3.3
0.017
20
29
0.002
0.014
0.09
0.10
25
36
0.006
0.032
5.8 4.7
0.13 0.13
0.09 0.08
0.11 0.12
26 27
45 40
0.006 0.007
0.018 0.032
29 23
46 39
3.8 2.9
0.026 0.027
0.07 0.08
0.10 0.10
21 24
33 41
0.006 0.006
0.029 0.023
4.4 3.4
0.07 0.07
0.09 0.10
17 17
24 26
0.08 0.09
0.14 0.11
4.0 2.8
0.023 0.023
0.09 0.10
0.13 0.13
21 21
34 33
0.007 0.007
0.031 0.024
0.08 0.08
0.10 0.10
21 21
36 36
2.2 2.2
0.04 0.04
0.018 0.017
0.08 0.08
0.09 0.11
19 20
34 39
0.007 0.007
0.040 0.029
2.0 2.4
0.017 0.018
20 21
30 30
0.002 0.002
0.012 0.008
0.09 0.08
0.10 0.11
26 25
44 43
0.007 0.007
0.025 0.029
APPENDIX A • DATA TABLES 157
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
CEDAR RAPIDS, IA
CO 2ND MAX 8-HOUR
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PMI8 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
CHAMPAIGN-URBANA, IL
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,. WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
CHARLESTON-NORTH CHARLESTON, SC
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO* ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
CHARLESTON, WV
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
Oj 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOj ARITHMETIC MEAN
2ND MAX 24-HOUR
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOj ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,o WEIGHTED ANNUAL MEAN
90TH PERCENTILE
CHARLOTTESV1LLE, VA
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
CHATTANOOGA, TN-GA
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,o WEIGHTED ANNUAL MEAN
90TH PERCENTILE
CHEYENNE, WY
PM,,, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
CHICAGO, IL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOa ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOS ARITHMETIC MEAN
2ND MAX 24-HOUR
CHICO-PARADISE, CA
CO 2ND MAX 8-HOUR
NO» ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
Trend
NS
NS
NS
NS
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
NS
NS
DOWN
DOWN
NS
DOWN
NS
DOWN
NS
NS
NS
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
UP
NS
DOWN
NS
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
#Trend
Sites
1
1
1
3
3
3
3
1
1
1
1
1
1
1
1
2
3
3
3
3
2
2
1
3
1
1
1
1
1
2
2
5
1
1
3
3
3
3
1
1
2
2
2
2
1
1
7
9
5
17
17
13
13
10
10
2
1
1
1
1989
3.5
0.07
0.08
33
55
0.006
0.044
0.08
0.09
32
56
0.005
0.025
5.9
0.02
0.008
0.08
0.09
29
45
0.003
0.024
2.9
0.02
0.021
0.07
0.10
35
62
0.014
0.062
7.0
0.03
0.017
0.09
0.12
33
50
30
50
0.08
0.10
36
57
19
30
4.5
0.09
0.026
0.08
0.10
37
61
0.008
0.039
6.4
0.016
0.08
0.10
1990
3.5
0.07
0.07
28
43
0.005
0.037
0.08
0.09
28
46
0.004
0.030
4.7
0.03
0.008
0.08
0.09
28
46
0.002
0.016
2.8
0.04
0.020
0.07
0.12
36
58
0.012
0.056
7.1
0.04
0.017
0.09
0.12
33
50
27
44
0.08
0.12
38
61
19
30
5.0
0.07
0.022
0.08
0.09
35
60
0.007
0.037
6.2
0.015
0.08
0.12
1991
4.1
0.05
0.08
29
45
0.005
0.033
0.08
0.08
30
47
0.005
0.038
4.9
0.04
0.008
0.07
0.09
25
40
0.003
0.017
3.1
0.02
0.020
0.08
0.12
29
47
0.009
0.036
6.3
0.01
0.016
0.10
0.12
31
50
28
47
0.09
0.10
38
63
19
30
4.2
0.06
0.021
0.07
0.11
33
51
0.008
0.040
7.4
0.016
0.08
0.09
1992
4.9
0.07
0.08
27
45
0.005
0.034
0.07
0.09
31
47
0.004
0.018
5.2
0.01
0.008
0.07
0.09
23
34
0.003
0.021
3.3
0.03
0.017
0.09
0.07
28
44
0.009
0.031
6.0
0.08
0.016
0.09
0.10
30
48
22
32
0.08
0.09
34
52
17
25
4.5
0.07
0.026
0.09
0.10
33
54
0.006
0.028
5.9
0.016
0.07
0.09
1993
3.2
0.07
0.07
22
35
0.004
0.023
0.07
0.07
22
41
0.004
0.015
5.8
0.01
0.008
0.07
0.10
21
35
0.002
0.014
2.2
0.02
0.018
0.06
0.08
29
52
0.009
0.034
5.6
0.02
0.017
0.09
0.13
28
41
24
40
0.08
0.10
32
52
16
24
4.6
0.06
0.026
0.08
0.09
31
51
0.006
0.031
4.7
0.016
0.08
0.09
1994
4.2
0.06
0.07
23
34
0.004
0.027
0.07
0.09
25
44
0.004
0.024
4.0
0.01
0.007
0.08
0.09
20
32
0.002
0.021
3.5
0.03
0.019
0.06
0.10
28
49
0.010
0.037
5.8
0.03
0.016
0.10
0.11
29
44
22
33
0.09
0.11
33
51
18
28
6.4
0.05
0.029
0.07
0.10
35
56
0.006
0.033
4.6
0.015
0.08
0.10
1995
2.6
0.06
0.08
23
39
0.003
0.021
0.08
0.10
22
44
0.003
0.011
6.4
0.01
0.007
0.07
0.09
19
28
0.002
0.012
2.4
0.02
0.020
0.08
0.11
26
40
0.007
0.023
4.7
0.01
0.016
0.09
0.11
28
42
23
41
0.09
0.11
32
49
15
26
3.5
0.05
0.029
0.08
0.12
32
55
0.005
0.023
4.1
0.014
0.08
0.09
1996
7.8
0.07
0.07
23
35
0.002
0.013
0.08
0.09
19
31
0.003
0.013
4.7
0.01
0.007
0.07
0.10
19
29
0.002
0.014
2.3
0.02
0.020
0.09
0.10
24
41
0.008
0.031
4.4
0.01
0.016
0.09
0.13
30
44
21
35
0.09
0.11
32
53
15
25
3.2
0.04
0.029
0.09
0.10
30
45
0.005
0.021
4.4
0.013
0.08
0.10
1997 1998
2.4 2.5
0.06 0.06
0.07 0.07
23 24
38 37
0.003 0.003
0.014 0.013
0.09 0.08
0.09 0.11
23 24
35 39
0.004 0.003
0.018 0.019
3.9 2.9
0.01 0.03
0.007 0.007
0.07 0.07
0.09 0.10
19 21
29 37
0.002 0.002
0.014 0.010
1.9 2.0
0.01 0.01
0.020 0.022
0.08 0.08
0.10 0.12
21 21
32 35
0.009 0.009
0.031 0.031
4.8 4.2
0.01 0.02
0.018 0.018
0.10 0.10
0.12 0.13
28 30
43 49
21 23
36 33
0.09 0.09
0.11 0.13
27 28
45 45
13 14
20 22
3.3 3.4
0.04 0.04
0.029 0.028
0.08 0.08
0.10 0.10
30 33
46 50
0.005 0.005
0.023 0.024
4.0 4.2
0.013 0.013
0.07 0.07
0.07 0.10
158 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, -(998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
CINCINNATI, OH-KY-IN
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
CLARKSVILLE-HOPKINSVILLE, TN-KY
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
CLEVELAND-LORAIN-ELYRIA, OH
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
COLORADO SPRINGS, CO
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
COLUMBIA, SC
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
COLUMBUS, GA-AL
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
COLUMBUS, OH
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
CORPUS CHRISTI, TX
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
CUMBERLAND, MD-WV
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
NS
NS
DOWN
UP
UP
NS
NS
DOWN
DOWN
NS
NS
NS
NS
DOWN
DOWN
NS
NS
DOWN
NS
NS
NS
DOWN
DOWN
#Trend
Sites
3
1
2
7
7
7
7
4
4
1
1
2
4
1
6
6
11
11
9
9
4
1
3
1
1
12
12
3
3
1
2
1
3
3
6
6
4
4
1
2
2
1
1
3
2
3
3
2
2
1
1
2
2
2
2
2
2
1
1
1989
4.9
0.07
0.024
0.09
0.11
41
69
0.012
0.046
0.007
0.042
5.9
0.19
0.025
0.09
0.10
37
60
0.012
0.042
6.0
0.03
0.015
0.07
0.08
27
43
0.004
0.013
6.5
0.03
0.013
0.08
0.11
20
57
0.002
0.011
2.04
0.07
0.09
26
38
5.7
0.08
0.09
0.11
31
55
0.008
0.038
0.08
0.10
30
45
0.003
0.019
• 0.011
0.049
1990
4.2
0.04
0.022
0.09
0.11
36
64
0.012
0.054
0.007
0.038
4.7
0.32
0.022
0.09
0.11
33
56
0.010
0.041
5.2
0.03
0.016
0.07
0.07
22
35
0.003
0.011
5.8
0.03
0.013
0.08
0.11
20
56
0.002
0.012
2.04
0.07
0.10
29
46
4.1
0.06
0.09
0.11
31
58
0.008
0.038
0.08
0.10
27
40
0.002
0.013
0.010
0.031
1991
4.2
0.04
0.022
0.09
0.12
32
57
0.012
0.044
0.006
0.029
4.7
0.18
0.022
0.08
0.11
35
59
0.010
0.039
4.8
0.03
0.016
0.06
0.08
25
40
0.003
0.011
6.0
0.05
0.009
0.08
0.10
17
55
0.002
0.013
2.04
0.07
0.09
27
40
4.8
0.06
0.09
0.11
30
53
0.007
0.033
0.08
0.11
31
43
0.003
0.027
0.009
0.028
1992
4.5
0.04
0.021
0.09
0.09
30
49
0.011
0.045
0.009
0.036
5.1
0.21
0.021
0.09
0.10
30
50
0.009
0.038
4.4
0.02
0.016
0.07
0.07
22
33
0.004
0.013
6.3
0.04
0.011
0.07
0.10
17
51
0.002
0.013
1.46
0.07
0.09
26
43
4.9
0.06
0.10
0.09
26
44
0.006
0.030
0.07
0.09
29
41
0.003
0.018
0.006
0.024
1993
4.7
0.05
0.022
0.08
0.10
31
58
0.011
0.044
0.010
0.058
4.3
0.21
0.022
0.08
0.11
29
54
0.008
0.039
4.1
0.02
0.015
0.06
0.06
22
36
0.003
0.011
5.6
0.02
0.013
0.08
0.11
16
49
0.002
0.011
1.01
0.08
0.10
25
37
3.9
0.04
0.08
0.10
27
48
0.007
0.034
0.08
0.12
29
52
0.003
0.024
0.008
0.027
1994
4.3
0.04
0.022
0.08
0.11
30
51
0.009
0.044
0.007
0.037
5.3
0.14
0.021
0.09
0.11
35
58
0.008
0.040
3.6
0.02
0.017
0.06
0.07
21
36
0.004
0.018
4.7
0.02
0.011
0.08
0.10
16
47
0.002
0.011
1.43
0.08
0.10
27
44
4.5
0.04
0.08
0.10
27
47
0.007
0.041
0.08
0.11
28
44
0.002
0.012
0.010
0.037
1995 1996 1997 1998
3.4
0.06
0.021
0.09
0.12
31
54
0.006
0.025
0.006
0.019
5.7
0.11
0.021
0.08
0.11
32
55
0.006
0.023
4.1
0.01
0.017
0.06
0.07
19
32
0.004
0.015
4.0
0.01
0.013
0.08
0.10
13
46
0.002
0.008
0.78
0.08
0.11
28
44
3.8
0.04
0.09
0.11
29
52
0.004
0.019
0.08
0.12
28
44
0.002
0.016
0.005
0.015
2.9 2.7
0.04 0.03
0.022 0.023
0.09 0.09
0.11 0.11
28 29
42 49
0.009 0.009
0.035 0.037
0.006 0.005
0.023 0.026
3.7 3.5
0.06 0.05
0.020 0.020
0.09 0.09
0.11 0.10
30 30
46 47
0.006 0.006
0.030 0.029
3.6 3.8
0.01 0.01
0.016 0.015
0.06 0.06
0.07 0.06
20 19
31 29
0.003 0.003
0.010 0.007
3.4 2.9
0.01 0.01
0.013 0.011
0.08 0.08
0.10 0.10
15 15
45 49
0.002 0.002
0.013 0.012
0.47 0.45
0.09 0.08
0.09 0.10
22 26
33 39
2.5 2.4
0.03 0.04
0.09 0.09
0.11 0.10
24 27
36 52
0.004 0.004
0.021 0.025
0.09 0.08
0.10 0.09
23 25
34 41
0.002 0.002
0.013 0.012
0.003 0.006
0.019 0.020
3.2
0.03
0.022
0.09
0.11
28
47
0.009
0.038
0.006
0.020
3.2
0.05
0.020
0.09
0.11
31
49
0.006
0.027
3.1
0.01
0.015
0.05
0.06
20
32
0.003
0.009
3.7
0.01
0.014
0.08
0.11
16
55
0.003
0.011
0.29
0.08
0.11
30
45
3.0
0.04
0.09
0.11
30
51
0.005
0.019
0.07
0.10
25
41
0.002
0.017
0.006
0.020
APPENDIX A
DATA TABLES
159
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
DALLAS. TX
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
DANBURY, CT
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,a WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
DAVENPORT-MOLINE-ROCK ISLAND, IA-IL
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,,, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
DAYTON-SPRINGFIELD, OH
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
Oa 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM«, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
DECATUR, AL
PM,a WEIGHTED ANNUAL MEAN
90TH PERCENTILE
DECATUR, IL
LEAD MAX QUARTERLY MEAN
O-, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,,, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO. ARITHMETIC MEAN
2ND MAX 24-HOUR
DENVER, CO
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O. 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
DES MOINES, IA
CO 2ND MAX 8-HOUR
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,8 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
DETROIT, Ml
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
DOTHAN, AL
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
Trend
NS
DOWN
UP
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
NS
DOWN
NS
NS
NS
NS
DOWN
DOWN
DOWN
NS
NS
NS
#Trend
Sites
1
10
1
2
2
5
5
1
1
1
1
1
1
1
2
2
4
4
3
3
2
2
3
3
3
3
2
2
1
1
1
1
1
1
1
1
1
6
3
2
5
5
11
11
2
2
3
2
2
3
3
6
6
2
8
8
6
6
10
10
1
1
1989
4.5
0.18
0.012
0.10
0.13
29
49
0.10
0.13
25
45
0.008
0.036
0.02
0.08
0.10
32
53
0.005
0.025
4.8
0.06
0.09
0.12
31
57
0.006
0.031
25
42
0.07
0.08
0.09
40
68
0.012
0.108
7.8
0.05
0.033
0.07
0.10
26
48
0.006
0.023
4.4
0.05
0.06
33
60
6.0
0.06
0.021
0.09
0.12
39
65
0.010
0.037
26
42
1990 1991
4.7 3.8
0.20 0.15
0.012 0.013
0.10 0.10
0.14 0.10
28 26
43 39
0.10 0.11
0.15 0.14
22 26
38 44
0.007 0.008
0.033 0.032
0.03 0.01
0.08 0.07
0.08 0.09
31 30
51 46
0.005 0.004
0.022 0.020
3.2 3.5
0.05 0.04
0.09 0.09
0.11 0.11
26 28
48 43
0.006 0.005
0.023 0.022
25 28
42 54
0.03 0.03
0.08 0.08
0.09 0.10
34 36
56 54
0.008 0.007
0.060 0.039
7.2 7.0
0.06 0.05
0.032 0.032
0.07 0.07
0.10 0.09
24 25
46 49
0.006 0.006
0.020 0.026
4.6 4.6
0.05 0.04
0.07 0.06
32 29
56 48
4.5 5.1
0.05 0.04
0.021 0.020
0.09 0.08
0.10 0.12
36 33
64 59
0.010 0.008
0.038 0.033
31 28
64 44
1992
5.6
0.17
0.015
0.06
0.12
26
40
0.10
0.12
22
38
0.007
0.027
0.02
0.08
0.10
29
51
0.004
0.019
3.6
0.04
0.09
0.10
25
41
0.005
0.020
25
41
0.03
0.09
0.09
38
63
0.005
0.023
8.3
0.06
0.032
0.07
0.09
24
43
0.007
0.038
3.9
0.04
0.08
28
55
4.2
0.04
0.020
0.09
0.10
28
47
0.007
0.030
25
43
1993
5.4
0.17
0.014
0.09
0.13
27
41
0.08
0.14
19
40
0.006
0.024
0.02
0.08
0.08
27
44
0.004
0.018
3.6
0.06
0.08
0.11
25
46
0.006
0.031
25
44
0.03
0.08
0.08
28
46
0.006
0.025
6.6
0.06
0.027
0.07
0.09
27
55
0.006
0.025
4.5
0.07
0.08
29
49
4.5
0.03
0.021
0.08
0.10
33
55
0.007
0.030
26
52
1994
5.3
0.11
0.016
0.10
0.12
26
41
0.10
0.13
26
37
0.006
0.037
0.02
0.07
0.09
31
51
0.004
0.023
3.4
0.04
0.09
0.11
24
40
0.006
0.032
22
35
0.05
0.07
0.10
29
53
0.007
0.030
6.1
0.04
0.032
0.07
0.09
23
45
0.006
0.025
3.9
0.05
0.07
30
52
6.6
0.04
0.022
0.08
0.12
38
61
0.007
0.032
28
47
1995
5.9
0.12
0.019
0.09
0.14
30
49
0.09
0.13
22
34
0.004
0.020
0.01
0.07
0.09
31
53
0.004
0.017
3.0
0.05
0.09
0.12
26
44
0.004
0.016
25
40
0.03
0.08
0.10
30
56
0.005
0.024
5.6
0.05
0.029
0.07
0.09
20
37
0.004
0.016
4.0
0.05
0.08
30
54
4.5
0.03
0.020
0.09
0.12
35
59
0.006
0.030
28
46
1996
5.5
0.07
0.019
0.11
0.12
30
49
0.09
0.11
22
36
0.005
0.020
0.02
0.08
0.09
30
50
0.003
0.016
2.4
0.04
0.09
0.11
23
38
0.005
0.027
21
32
0.02
0.08
0.10
28
43
0.005
0.022
4.8
0.03
0.027
0.07
0.09
20
37
0.005
0.020
3.2
0.07
0.08
31
53
3.9
0.03
0.021
0.09
0.10
31
50
0.006
0.034
22
36
1997
3.7
0.07
0.018
0.09
0.12
26
41
0.08
0.14
21
35
0.005
0.024
0.02
0.08
0.08
30
49
0.003
0.015
3.0
0.04
0.10
0.11
24
41
0.005
0.027
23
41
0.03
0.09
0.09
27
41
0.006
0.021
4.7
0.02
0.029
0.07
0.09
21
42
0.005
0.021
3.0
0.06
0.08
32
59
3.3
0.04
0.020
0.08
0.11
28
45
0.005
0.027
25
45
1998
2.7
0.07
0.016
0.09
0.11
26
41
0.11
0.12
20
30
0.004
0.020
0.01
0.07
0.09
32
56
0.003
0.013
2.8
0.03
0.09
0.12
25
42
0.005
0.019
25
41
0.02
0.08
0.09
32
49
0.005
0.020
3.9
0.02
0.029
0.07
0.10
21
40
0.004
0.018
5.7
0.06
0.07
26
45
3.1
0.04
0.021
0.08
0.11
29
53
0.006
0.032
27
41
160 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
DUBUQUE, IA
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
DULUTH-SUPERIOR, MN-WI
CO 2ND MAX 8-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
DUTCHESS COUNTY, NY
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
EL PASO, TX
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
ELMIRA, NY
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
ERIE, PA
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
EUGENE-SPRINGFIELD, OR
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
EVANSVILLE-HENDERSON, IN-KY
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
FAYETTEVILLE, NC
03 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
FAYETTEVILLE-SPRINGDALE-ROGERS, AR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
FLINT, Ml
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
FLORENCE, AL
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
FORT COLLINS-LOVELAND, CO
CO 2ND MAX 8-HOUR
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SS'^^^^MTEWiiirerea-:.--™;-™
Trend
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
NS
NS
DOWN
NS
NS
NS
NS
NS
DOWN
DOWN
NS
DOWN
NS
NS
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
#Trend
Sites
1
1
1
6
6
1
1
5
4
2
3
3
8
8
3
3
1
1
1
1
1
1
1
1
1
2
1
2
2
5
5
1
1
5
5
4
4
7
7
2
2
1
1
1
1
1
1
1
1
1
1
1
2
2
1
1
1989
0.005
0.030
. 9.9
26
39
0.10
0.13
9.8
0.30
0.025
0.08
0.13
37
68
0.013
0.055
0.07
0.09
0.005
0.026
0.015
0.09
0.12
0.014
0.074
5.5
0.02
0.06
0.08
31
62
2.3
0.020
0.09
0.11
34
54
0.013
0.056
0.08
0.10
29
47
26
37
0.08
0.10
24
39
0.005
0.036
8.3
0.07
0.09
29
49
;fflr
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
FORT LAUDERDALE, FL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
FORT MYERS-CAPE CORAL, FL
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
FORT SMITH, AR-OK
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
FORT WAYNE, IN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,o WEIGHTED ANNUAL MEAN
90TH PERCENTILE
FORT WORTH-ARLINGTON, TX
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOj ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,8 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
FRESNO, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOt ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
GADSDEN, AL
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
GALVESTON-TEXAS C1TY.TX
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
GARY, IN
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O-j 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,,, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
GLENS FALLS, NY
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
GOLDSBORO, NC
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
GRAND FORKS, ND-MN
PM,a WEIGHTED ANNUAL MEAN
90TH PERCENTILE
GRAND RAPIDS-MUSKEGON-HOLLAND, Ml
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,o WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
NS
NS
NS
NS
DOWN
NS
DOWN
NS
NS
NS
NS
DOWN
DOWN
NS
NS
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
NS
DOWN
NS
NS
DOWN
DOWN
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
#Trend
Sites
5
1
1
3
3
1
1
1
1
1
1
1
1
2
2
1
2
2
3
3
1
1
4
1
4
5
5
5
5
2
2
1
1
1
3
3
1
1
2
4
3
3
8
8
5
5
1
1
1
1
1
1
1
3
4
4
2
2
1
1
1989
4.8
0.03
0.009
0.08
0.11
0.08
0.10
28
43
0.09
0.12
29
53
4.8
0.03
0.013
0.10
0.13
24
38
0.001
0.007
5.7
0.07
0.021
0.10
0.14
55
107
28
45
0.03
0.10
0.14
28
47
0.008
0.045
4.3
0.23
0.08
0.10
33
54
0.011
0.047
0.004
0.023
27
46
24
48
4.5
0.03
0.10
0.13
29
46
0.004
0.016
1990
4.0
0.01
0.009
0.08
0.09
0.08
0.08
26
38
0.09
0.09
27
53
4.2
0.03
0.012
0.10
0.14
24
41
0.002
0.008
5.7
0.07
0.021
0.10
0.14
55
107
33
55
0.02
0.10
0.15
24
40
0.007
0.063
4.2
0.21
0.08
0.09
33
52
0.010
0.048
0.005
0.040
27
46
25
38
3.5
0.02
0.10
0.13
30
55
0.004
0.012
1991
4.1
0.02
0.009
0.07
0.09
0.07
0.08
25
37
0.08
0.10
27
44
3.7
0.02
0.014
0.10
0.15
23
33
0.002
0.006
6.1
0.04
0.021
0.10
0.15
54
100
32
56
0.02
0.09
0.15
22
38
0.007
0.050
4.1
0.11
0.08
0.11
29
45
0.008
0.028
0.004
0.020
27
46
20
34
4.0
0.02
0.10
0.13
26
41
0.004
0.014
1992
4.2
0.04
0.009
0.06
0.10
0.06
0.08
24
36
0.09
0.09
23
38
4.0
0.03
0.015
0.11
0.12
21
31
0.003
0.013
4.6
0.04
0.020
0.11
0.14
45
73
31
52
0.02
0.09
0.10
24
35
0.005
0.039
4.4
0.11
0.09
0.11
26
43
0.007
0.028
0.004
0.017
24
36
18
33
3.2
0.02
0.10
0.11
35
54
0.003
0.015
1993
3.7
0.03
0.010
0.08
0.10
0.07
0.08
25
39
0.09
0.10
23
36
3.4
0.03
0.013
0.08
0.11
21
33
0.001
0.005
4.2
0.03
0.021
0.11
0.14
43
86
33
58
0.03
0.07
0.18
24
45
0.005
0.056
4.7
0.08
0.08
0.09
24
39
0.007
0.032
0.004
0.018
24
36
17
28
3.2
0.01
0.08
0.10
22
39
0.003
0.012
1994
3.6
0.03
0.009
0.08
0.09
0.07
0.09
24
38
0.08
0.11
24
43
3.2
0.03
0.017
0.09
0.13
20
33
0.002
0.006
4.9
0.02
0.020
0.11
0.13
40
63
30
46
0.02
0.11
0.13
. 23
36
0.006
0.052
5.6
0.17
0.07
0.11
26
42
0.006
0.032
0.004
0.027
21
33
16
28
4.0
0.01
0.08
0.11
27
46
0.003
0.013
1995
3.9
0.02
0.011
0.07
0.09
0.08
0.09
26
44
0.10
0.11
24
44
3.2
0.03
0.017
0.10
0.14
24
38
0.001
0.004
4.2
0.02
0.020
0.10
0.13
41
80
30
43
0.03
0.09
0.20
25
40
0.006
0.089
3.9
0.12
0.08
0.12
25
41
0.005
0.022
0.003
0.011
20
30
18
30
4.6
0.01
0.09
0.12
21
40
0.002
0.011
1996
3.3
0.05
0.010
0.07
0.09
0.07
0.07
25
36
0.09
0.11
17
28
3.0
0.02
0.015
0.10
0.13
25
40
0.001
0.011
4.2
0.01
0.019
0.10
0.14
35
59
23
36
0.02
0.14
0.11
19
27
0.014
0.067
3.3
0.13
0.10
0.11
21
33
0.005
0.023
0.002
0.013
23
33
15
22
3.3
0.01
0.10
0.12
20
35
0.002
0.011
1997 1998
3.2 2.5
0.04 0.04
0.010 0.010
0.07 0.07
0.09 0.10
0.06 0.07
0.08 0.11
22 22
39 39
0.09 0.09
0.10 0.10
20 24
28 39
3.0 2.9
0.02 0.02
0.016 0.013
0.09 0.09
0.12 0.13
22 22
34 34
0.001 0.001
0.011 0.011
3.5 3.5
0.01 0.01
0.018 0.018
0.11 0.10
0.13 0.15
40 34
77 62
26 31
47 50
0.02 0.02
0.08 0.10
0.18 0.15
20 20
32 32
0.006 0.004
0.053 0.039
3.7 3.9
0.10 0.10
0.09 0.09
0.11 0.11
22 23
33 36
0.005 0.005
0.024 0.027
0.002 0.002
0.013 0.013
23 22
36 34
15 15
22 22
2.4 2.9
0.01 0.01
0.09 0.08
0.10 0.11
19 21
32 38
0.002 0.002
0.008 0.008
162 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
GREAT FALLS, MT
CO 2ND MAX 8-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
GREELEY, CO
CO 2ND MAX 8-HOUR
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
GREEN BAY, Wl
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
GREENSBORO-WINSTON-SALEM-HIGH POINT,
CO 2ND MAX 8-HOUR
N02 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
GREENVILLE, NC
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
GREENVILLE-SPARTANBURG-ANDERSON, SC
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
HAMILTON-MIDDLETOWN, OH
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
HARRISBURG-LEBANON-CARLISLE, PA
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
HARTFORD, CT
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
HONOLULU, HI
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
HOUMA, LA
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
Trend
NS
NS
NS
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NC
DOWN
NS
NS
UP
DOWN
DOWN
NS
NS
NS
NS
DOWN
UP
UP
NS
NS
NS
NS
NS
NS
DOWN
DOWN
NS
NS
NS
NS
NS
NS
DOWN
NS
DOWN
NS
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
UP
NS
NS
NS
DOWN
NS
NS
NS
#Trend
Sites
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
3
1
1
1
1
3
4
4
1
1
2
2
4
4
2
2
1
2
3
3
1
1
2
2
2
1
3
3
6
6
4
4
3
2
1
1
1
1
1
3
1
1 '
1989
5.6
20
31
7.3
0.07
0.10
30
50
0.006
0.024
9.7
0.016
0.08
0.09
32
51
0.007
0.024
0.08
0.10
0.04
0.08
0.10
0.002
0.011
0.09
0.11
34
60
0.010
0.040
0.04
0.014
0.09
0.10
21
33
0.006
0.029
6.7
0.020
0.11
0.15
23
37
0.007
0.034
2.6
0.03
0.02
0.05
16
20
0.002
0.006
0.08
0.11
1990
5.6
24
39
7.1
0.07
0.11
25
43
0.005
0.020
6.8
0.017
0.08
0.11
31
49
0.008
0.023
0.08
0.10
0.04
0.08
0.09
0.002
0.011
0.09
0.12
34
60
0.010
0.037
0.04
0.013
0.09
0.11
19
35
0.005
0.021
6.7
0.019
0.11
0.15
20
. 35
0.007
0.030
2.2
0.01
0.02
0.05
16
23
0.002
0.006
0.08
0.12
1991
6.6
21
44
7.8
0.08
0.10
26
51
0.005
0.042
6.6
0.016
0.09
0.10
31
48
0.007
0.027
0.08
0.09
0.04
0.08
0.10
0.003
0.017
0.10
0.11
36
61
0.009
0.040
0.04
0.014
0.09
0.11
22
39
0.006
0.021
6.1
0.020
0.10
0.16
23
38
0.007
0.030
2.0
0.01
0.03
0.05
17
25
0.002
0.006
0.08
0.10
1992
5.8
21
40
7.5
0.08
0.08
25
43
0.004
0.021
5.7
0.015
0.08
0.10
27
41
0.006
0.019
0.08
0.10
0.02
0.08
0.09
0.003
0.013
0.09
0.10
30
51
0.007
0.033
0.04
0.013
0.10
0.09
18
27
0.005
0.022
6.1
0.017
0.11
0.12
20
34
0.006
0.027
2.1
0.01
0.04
0.06
17
22
0.002
0.006
0.08
0.09
1993
6.9
21
40
5.8
0.06
0.09
23
39
0.003
0.018
5.5
0.017
0.08
0.12
27
45
0.006
0.022
0.08
0.11
0.02
0.08
0.11
0.003
0.012
0.07
0.12
31
63
0.008
0.035
0.04
0.011
0.08
0.11
21
30
0.006
0.021
5.6
0.018
0.09
0.15
18
31
0.005
0.019
2.4
• 0.01
0.05
0.06
16
22
0.002
0.009
0,07
0.10
1994
4.8
21
34
5.2
0.06
0.09
23
37
0.003
0.015
6.0
0.017
0.09
0.11
25
35
0.007
0.021
0.09
0.09
0.02
0.09
0.10
0.003
0.016
0.09
0.11
30
53
0.008
0.038
0.04
0.015
0.09
0.12
22
44
0.007
0.035
6.4
0.020
0.10
0.13
20
35
0.006
0.027
2.3
0.00
0.05
0.06
19
26
0.002
0.006
0.08
0.10
1995
6.2
18
30
5.3
0.07
0.09
20
34
0.004
0.017
6.2
0.016
0.09
0.11
26
39
0.007
0.025
0.08
0.10
0.02
0.08
0.11
0.001
0.007
0.09
0.13
34
58
0.005
0.019
0.04
0.014
0.09
0.11
21
32
0.005
0.017
5.8
0.017
0.10
0.13
16
29
0.004
0.019
2.0
0.00
0.05
0.06
15
23
0.001
0.005
0.09
0.14
1996
5.4
19
35
7.0
0.07
0.10
18
30
0.003
0.011
4.3
0.016
0.09
0.11
24
35
0.007
0.026
0.08
0.10
0.01
0.09
0.11
0.002
0.012
0.09
0.11
29
45
0.007
0.025
0.04
0.015
0.09
0.10
19
31
0.005
0.021
5.0
0.016
0.10
0.10
17
30
0.004
0.018
1.9
0.01
0.05
0.05
16
24
0.001
0.007
0.10
0.09
1997
6.4
20
32
4.8
0.07
0.10
18
30
0.003
0.017
4.7
0.017
0.09
0.11
24
37
0.007
0.023
0.09
0.12
0.01
0.09
0.10
0.003
0.014
0.09
0.11
30
54
0.007
0.034
0.04
0.013
0.08
0.11
22
33
0.005
0.022
4.8
0.018
0.08
0.14
18
33
0.004
0.021
1.8
0.02
0.04
0.05
18
23
0.001
0.005
0.08
0.10
1998
4.5
20
32
4.4
0.07
0.10
17
30
0.003
0.011
5.4
0.017
0.09
0.12
25
39
0.006
0.023
0.10
0.11
0.02
0.09
0.12
0.003
0.015
0.09
0.11
30
53
0.006
0.021
0.04
0.012
0.09
0.11
22
33
0.005
0.017
5.4
0.020
0.10
0.12
18
31
0.004
0.019
1.7
0.02
0.05
0.06
20
27
0.002
0.007
0.08
0.11
APPENDIX A • DATA TABLES 163
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
HOUSTON, TX
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOj ARITHMETIC MEAN
2ND MAX 24-HOUR
HUNTINQTON-ASHLAND, WV-KY-OH
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
HUNTSVILLE, AL
CO 2ND MAX 8-HOUR
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PMI8 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
INDIANAPOLIS, IN
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM!() WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO. ARITHMETIC MEAN
2ND MAX 24-HOUR
JACKSON, MS
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,a WEIGHTED ANNUAL MEAN
90TH PERCENTILE
JACKSON, TN
PM.» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
JACKSONVILLE, FL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO. ARITHMETIC MEAN
2ND MAX 24-HOUR
JACKSONVILLE, NC
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
JAMESTOWN, NY
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
JERSEY CITY, NJ
CO 2ND MAX 8-HOUR
NO. ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,« WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
UP
UP
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
UP
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
NS
DOWN
DOWN
#Trend
Sites
4
2
4
10
10
5
5
7
7
1
2
3
3
5
5
8
8
1
1
1
2
2
2
6
1
6
6
13
13
8
8
2
2
1
1
2
2
5
2
1
2
2
3
3
5
5
1
1
1
1
2
2
2
2
1
1
1
1
3
3
2
2
1989
5.8
0.04
0.022
0.11
0.18
32
53
0.005
0.026
5.5
0.06
0.09
0.12
34
58
0.013
0.075
5.2
0.07
0.09
32
49
4.0
0.66
0.018
0.09
0.11
35
58
0.010
0.038
0.07
0.08
26
44
31
47
5.5
0.04
0.015
0.08
0.11
36
50
0.004
0.037
24
39
0.08
0.10
21
39
0.011
0.051
7.3
0.031
0.10
0.12
33
51
0.014
0.047
1990
6.8
0.02
0.023
0.11
0.19
31
50
0.005
0.025
4.7
0.04
0.09
0.11
34
54
0.012
0.070
4.2
0.07
0.09
32
47
4.0
0.76
0.018
0.09
0.10
33
54
0.009
0.033
0.07
0.10
26
44
28
44
4.2
0.04
0.015
0.08
0.11
34
45
0.004
0.037
24
39
0.08
0.10
21
39
0.010
0.047
7.2
0.030
0.10
0.18
31
52
0.013
0.043
1991
6.0
0.02
0.022
0.12
0.17
31
48
0.005
0.025
4.4
0.04
0.09
0.13
32
50
0.012
0.050
4.1
0.08
0.11
28
50
5.2
0.51
0.018
0.09
0.10
31
49
0.008
0.029
0.08
0.09
26
44
27
39
3.7
0.03
0.014
0.08
0.09
32
44
0.003
0.023
24
39
0.08
0.10
21
39
0.010
0.039
7.5
0.028
0.11
0.14
32
53
0.012
0.035
1992
6.8
0.01
0.022
0.10
0.16
30
48
0.005
0.022
4.1
0.04
0.10
0.10
29
46
0.010
0.043
4.2
0.08
0.11
27
44
3.5
0.45
0.018
0.09
0.09
28
43
0.007
0.029
0.07
0.08
27
43
27
41
4.1
0.02
0.014
0.07
0.10
26
38
0.003
0.023
23
35
0.08
0.10
18
29
0.009
0.039
6.0
0.028
0.12
0.11
26
43
0.010
0.041
1993
5.6
0.01
0.019
0.10
0.16
30
50
0.005
0.020
3.8
0.04
0.08
0.11
28
52
0.011
0.052
4.0
0.09
0.11
24
41
4.0
0.45
0.018
0.08
0.10
28
51
0.008
0.036
0.07
0.09
23
38
23
37
4.0
0.05
0.015
0.08
0.11
27
37
0.003
0.025
23
35
0.08
0.10
16
32
0.009
0.041
5.6
0.027
0.09
0.13
27
44
0.009
0.030
1994
4.9
0.01
0.021
0.09
0.15
31
50
0.004
0.018
5.2
0.03
0.09
0.13
31
52
0.010
0.049
3.5
0.09
0.11
23
34
3.5
0.69
0.019
0.08
0.11
28
46
0.007
0.039
0.07
0.09
21
32
23
32
3.8
0.02
0.014
0.08
0.10
26
39
0.003
0.030
20
28
0.08
0.09
16
33
0.008
0.053
5.9
0.026
0.10
0.12
32
55
0.009
0.036
1995
4.0
0.01
0.021
0.10
0.17
30
48
0.004
0.026
3.8
0.04
0.09
0.12
30
48
0.009
0.034
3.6
0.08
0.10
23
33
3.9
0.21
0.020
0.09
0.11
28
46
0.005
0.021
0.07
0.09
23
34
25
43
3.6
0.03
0.016
0.07
0.11
27
41
0.003
0.019
20
29
0.08
0.10
16
30
0.007
0.039
6.2
0.026
0.10
0.13
25
40
0.007
0.026
1996
5.3
0.00
0.020
0.12
0.16
26
39
0.004
0.022
3.7
0.03
0.09
0.10
26
39
0.008
0.028
3.0
0.08
0.10
21
32
2.8
0.06
0.018
0.09
0.12
23
34
0.005
0.024
0.08
0.09
22
34
22
34
3.1
0.02
0.015
0.07
0.09
24
32
0.003
0.020
22
32
.0.09
0.10
17
28
0.006
0.033
4.9
0.027
0.10
0.12
27
41
0.008
0.027
1997 1998
4.3 3.8
0.00 0.00
0.021 0.019
0.10 0.11
0.17 0.17
29 29
48 48
0.003 0.003
0.017 0.018
3.8 7.2
0.02 0.02
0.08 0.08
0.11 0.13
28 26
45 44
0.008 0.008
0.031 0.033
3.1 3.3
0.08 0.09
0.10 0.12
21 22
39 35
3.2 2.7
0.04 0.05
0.015 0.019
0.10 0.09
0.10 0.11
23 24
36 39
0.005 0.005
0.023 0.021
0.08 0.08
0.10 0.11
24 20
36 32
23 23
34 34
2.6 2.8
0.02 0.02
0.014 0.015
0.07 0.08
0.10 0.10
24 27
35 38
0.003 0.003
0.017 0.021
20 22
32 37
0.08 0.09
0.11 0.11
17 19
34 37
0.006 0.006
0.029 0.026
4.3 4.1
0.026 0.027
0.09 0.11
0.12 0.12
26 26
41 41
0.008 0.007
0.025 0.022
164 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
JOHNSON CITY-KINGSPORT-BRISTOL, TN-VA
CO 2ND MAX 8-HOUR
N02 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
JOHNSTOWN, PA
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
KALAMAZOO-BATTLE CREEK, Ml
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
KANSAS CITY, MO-KS
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
N0a ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
KENOSHA, Wl
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
KNOXVILLE, TN
CO 2ND MAX 8-HOUR
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
LAKE CHARLES, LA
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
LAKELAND-WINTER HAVEN, FL
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
LANCASTER, PA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
LANSING-EAST LANSING, Ml
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
LAS CRUCES, NM
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
NS
NS
NS
NS
DOWN
DOWN
NS
NS
NS
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
UP
UP
DOWN
DOWN
NS
NS
NS
NS
DOWN
UP
UP
DOWN
DOWN
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
UP
NS
NS
DOWN
NS
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
#Trend
Sites
1
1
1
1
3
3
3
3
1
1
1
1
1
1
1
1
3
5
3
6
6
7
7
5
5
2
2
1
4
4
8
8
3
3
1
1
2
2
1
1
1
1
1
1
1
1
1
2
2
1
2
2
2
3
3
2
2
1988
3.7
0.019
0.08
0.11
31
50
0.010
0.053
4.1
0.019
0.08
0.10
0.017
0.089
34
61
5.2
0.06
0.011
0.07
0.10
34
56
0.004
0.016
0.10
0.13
6.7
0.07
0.09
32
51
0.006
0.030
0.09
0.12
0.004
0.015
4.1
0.05
0.018
0.09
0.10
31
52
0.007
0.037
0.08
0.10
6.1
0.16
0.07
0.10
45
74
0.010
0.061
1989
3.4
0.019
0.08
0.12
32
50
0.009
0.044
3.7
0.018
0.08
0.10
0.014
0.046
28
58
4.4
0.03
0.011
0.07
0.10
31
51
0.003
0.022
0.10
0.11
5.1
0.07
0.11
32
53
0.006
0.030
0.09
0.11
0.004
0.018
3.4
0.06
0.017
0.09
0.10
31
52
0.006
0.028
0.08
0.10
6.3
0.17
0.07
0.09
35
60
0.011
0.056
1990
3.3
0.019
0.10
0.12
32
50
0.009
0.044
4.8
0.019
0.08
0.11
0.015
0.043
29
56
4.0
0.03
0.010
0.07
0.10
32
51
0.003
0.017
0.08
0.14
4.5
0.09
0.10
34
52
0.006
0.034
0.09
0.12
0.004
0.015
2.6
0.04
0.018
0.09
0.12
30
45
0.006
0.023
0.08
0.11
6.5
0.15
0.07
0.09
31
52
0.010
0.055
1991
3.0
0.018
0.08
0.10
29
44
0.009
0.039
4.4
0.018
0.10
0.09
0.013
0.052
27
42
3.9
0.02
0.010
0.08
0.09
30
47
0.003
0.016
0.11
0.11
4.5
0.08
0.10
30
47
0.006
0.034
0.09
0.11
0.004
0.015
2.6
0.04
0.015
0.10
0.11
27
41
0.006
0.023
0.08
0.09
4.9
0.13
0.07
0.09
31
57
0.009
0.052
1992
6.5
0.017
0.08
0.13
29
50
0.008
0.042
4.2
0.017
0.07
0.10
0.015
0.049
24
39
4.2
0.02
0.009
0.08
0.10
30
48
0.003
0.020
0.08
0.11
4.6
0.08
0.11
30
48
0.006
0.037
0.07
0.10
0.004
0.019
3.0
0.04
0.015
0.09
0.12
31
54
0.007
0.026
0.08
0.10
8.7
0.12
0.07
0.09
30
47
0.006
0.055
1993
3.4
0.017
0.09
0.10
28
42
0.009
0.045
4.1
0.018
0.08
0.09
0.014
0.080
. 26
44
4.3
0.02
0.010
0.07
0.10
30
47
0.003
0.025
0.09
0.12
4.3
0.09
0.11
32
49
0.006
0.034
0.08
0.10
0.004
0.016
3.8
0.04
0.019
0.10
0.11
38
61
0.006
0.030
0.08
0.09
5.0
0.05
0.07
0.09
33
55
0.004
0.023
1994
3.0
0.018
0.08
0.11
27
43
0.008
0.039
3.5
0.015
0.08
0.10
0.012
0.042
26
50
3.3
0.02
0.010
0.08
0.12
24
44
0.003
0.018
0.09
0.12
4.1
0.09
0.12
31
49
0.007
0.034
0.08
0.11
0.004
0.013
2.4
0.04
0.016
0.09
0.12
33
55
0.006
0.018
0.08
0.10
4.4
0.09
0.07
0.09
34
55
0.004
0.021
1995
3.0
0.018
0.09
0.10
26
42
0.009
0.044
4.8
0.018
0.09
0.10
0.011
0.034
22
33
3.2
0.03
0.012
0.09
0.10
33
56
0.004
0.024
0.10
0.13
3.3
0.09
0.11
31
49
0.006
0.037
0.08
0.09
0.005
0.019
2.6
0.04
0.017
0.10
0.10
31
46
0.005
0.021
0.08
0.09
4.3
0.07
0.07
0.09
33
50
0.004
0.030
1996 1997
3.5 3.4
0.018 0.017
0.08 0.08
0.11 0.12
25 25
42 39
0.009 0.009
0.050 0.043
2.7 3.1
0.016 0.015
0.08 0.09
0.10 0.12
0.009 0.008
0.030 0.027
23 27
38 47
3.2 3.7
0.10 0.10
0.010 0.012
0.08 0.09
0.11 0.12
26 27
40 44
0.004 0.003
0.013 0.010
0.08 0.09
0.11 0.12
4.8 3.9
0.09 0.10
0.12 0.13
26 26
44 41
0.006 0.005
0.033 0.028
0.08 0.09
0.11 0.12
0.005 0.006
0.016 0.022
3.3 1.9
0.04 0.04
0.016 0.015
0.09 0.10
0.13 0.12
34 34
50 50
0.007 0.006
0.023 0.020
0.08 0.08
0.09 0.10
4.8 4.2
0.07 0.07
0.07 0.06
0.08 0.09
27 27
43 42
0.003 0.003
0.014 0.012
APPENDIX A • DATA TABLES 165
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
LAS VEGAS, NV-AZ
CO 2ND MAX 8-HOUR
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
LAWRENCE, MA-NH
Oa 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOS ARITHMETIC MEAN
2ND MAX 24-HOUR
LAWTON, OK
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
LEWISTON-AUBURN, ME
PM,. WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO» ARITHMETIC MEAN
2ND MAX 24-HOUR
LEXINGTON, KY
CO 2ND MAX 8-HOUR
NOj ARITHMETIC MEAN
Oj 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO4 ARITHMETIC MEAN
2ND MAX 24-HOUR
LIMA, OH
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
SOS ARITHMETIC MEAN
2ND MAX 24-HOUR
LINCOLN, NE
CO 2ND MAX 8-HOUR
Oj 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
LITTLE ROCK-NORTH LITTLE ROCK, AR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO3 ARITHMETIC MEAN
2ND MAX 24-HOUR
LONGVIEW-MARSHALL, TX
O5 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
LOS ANGELES-LONG BEACH, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOj ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,« WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
LOUISVILLE, KY-IN
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
NS
DOWN
NS
NS
NS
NS
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
DOWN
DOWN
NS
NS
NS
NS
DOWN
NS
NS
NS
NS
DOWN
DOWN
NS
NS
NS
DOWN
NS
NS
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
#Trend
Sites
2
3
3
1
1
1
1
1
1
2
2
1
1
1
1
1
1
1
1
2
2
3
3
1
1
1
1
1
1
2
1
1
2
2
1
2
2
4
4
1
1
1
1
13
6
13
14
14
9
9
4
4
4
2
4
4
6
6
4
4
1988
10.0
0.08
0.10
60
107
0.08
0.11
21
32
0.009
0.036
32
53
25
41
0.008
0.035
5.6
0.019
0.09
0.11
31
50
0.006
0.034
0.09
0.10
0.006
0.033
6.1
0.06
0.06
33
51
0.009
0.07
0.09
29
49
0.002
0.010
0.09
0.10
9.6
0.09
0.044
0.14
0.22
57
88
0.004
0.015
6.0
0.05
0.08
0.11
35
59
0.010
0.055
1989
10.9
0.08
0.10
69
127
0.08
0.09
21
32
0.008
0.029
30
51
25
41
0.007
0.027
3.7
0.017
0.09
0.10
29
48
0.006
0.020
0.09
0.10
0.005
0.026
6.2
0.06
0.07
29
49
0.009
0.07
0.10
29
49
0.003
0.014
0.09
0.13
9.0
0.09
0.041
0.14
0.19
49
78
0.003
0.012
5.9
0.04
0.08
0.11
34
56
0.010
0.041
1990
9.5
0.07
0.09
59
88
0.07
0.12
18
30
0.007
0.026
27
43
29
50
0.006
0.023
4.9
0.016
0.08
0.09
29
46
0.008
0.025
0.08
0.10
0.006
0.021
7.4
0.06
0.07
30
53
0.009
0.08
0.10
. 25
43
0.003
0.012
0.09
0.11
8.8
0.10
0.041
0.12
0.19
53
80
0.003
0.013
5.9
0.05
0.08
0.12
33
51
0.010
0.037
1991
7.9
0.07
0.09
48
76
0.09
0.09
19
32
0.008
0.027
26
41
24
43
0.005
0.020
3.8
0.016
0.08
0.08
25
40
0.007
0.030
0.09
0.10
0.004
0.020
4.5
0.06
0.07
25
42
0.012
0.08
0.09
28
47
0.005
0.012
0.08
0.10
7.8
0.08
0.038
0.13
0.20
41
64
0.004
0.015
5.2
0.05
0.09
0.09
30
48
0.009
0.034
1992
8.6
0.08
0.10
43
75
0.07
0.10
18
36
0.008
0.026
27
35
24
49
0.007
0.025
6.5
0.017
0.06
0.10
24
42
0.007
0.026
0.08
0.10
0.005
0.023
4.3
0.07
0.06
26
38
0.009
0.08
0.10
27
44
0.006
0.017
0.08
0.11
6.8
0.06
0.036
0.13
0.17
40
65
0.003
0.011
5.4
0.05
0.07
0.13
29
51
0.010
0.035
1993
8.8
0.08
0.09
47
67
0.08
0.10
16
32
0.006
0.027
28
43
20
35
0.006
0.025
4.2
0.016
0.08
0.10
28
46
0.008
0.037
0.09
0.10
0.004
0.036
4.0
0.05
0.08
28
46
0.011
0.08
0.09
27
47
0.003
0.009
0.09
0.10
8.0
0.06
0.039
0.12
0.17
39
59
0.003
0.008
5.9
0.02
0.09
0.12
30
47
0.010
0.040
1994
7.8
0.08
0.09
47
77
0.08
0.08
13
24
0.006
0.025
25
44
20
37
0.004
0.020
3.0
0.017
0.09
0.11
25
40
0.006
0.016
0.09
0.11
0.003
0.015
4.9
0.06
0.07
25
45
0.011
0.08
0.11
29
50
0.002
0.008
0.08
0.15
7.5
0.05
0.038
0.11
0.15
39
64
0.003
0.008
4.4
0.05
0.09
0.12
29
46
0.008
0.028
1995
8.4
0.07
0.09
53
82
0.07
0.09
14
22
0.005
0.019
28
44
20
31
0.004
0.018
3.1
0.014
0.08
0.09
24
39
0.006
0.020
0.09
0.11
0.003
0.015
3.4
0.06
0.06
28
44
0.011
0.09
0.10
26
41
0.002
0.009
0.10
0.11
6.8
0.05
0.035
0.11
0.14
38
61
0.003
0.008
3.9
0.02
0.09
0.11
26
44
0.007
0.031
1996 1997
7.8 8.2
0.08 0.07
0.09 0.09
60 60
90 90
0.08 0.08
0.10 0.10
15 15
25 28
0.005 0.006
0.020 0.021
26 26
48 48
21 18
35 31
0.004 0.004
0.017 0.019
5.2 5.2
0.014 0.011
0.08 0.08
0.09 0.10
22 23
37 39
0.006 0.006
0.016 0.023
0.09 0.08
0.03 0.10
0.003 0.003
0.016 0.017
5.0 4.3
0.05 0.05
0.06 0.07
24 26
39 40
0.010 0.011
0.08 0.08
0.10 0.10
25 25
42 42
0.002 0.002
0.006 0.006
0.08 0.09
0.12 0.13
6.6 6.1
0.05 0.04
0.033 0.033
0.10 0.09
0.12 0.15
39 33
57 55
0.003 0.003
0.007 0.009
5.0 4.4
0.02 0.02
0.09 0.09
0.12 0.12
29 26
48 42
0.006 0.007
0.031 0.033
166 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
TabIeA-14.
Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
LOWELL, MA-NH
CO 2ND MAX 8-HOUR
LUBBOCK,TX
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
LYNCHBURG, VA
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
MADISON, W!
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
MANCHESTER, NH
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
MANSFIELD, OH
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
MEDFORD-ASHLAND, OR
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
MELBOURNE-TITUSVILLE-PALM BAY, FL
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
MEMPHIS, TN-AR-MS
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
MERCED, CA
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
MIAMI, FL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
MIDDLESEX-SOMERSET-HUNTERDON, NJ
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
MILWAUKEE-WAUKESHA, Wl
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
NS
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
NS
DOWN
NS
DOWN
DOWN
DOWN
NS
DOWN
NS
UP
NS
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
#Trend
Sites
1
1
1
1
1
1
1
2
2
1
1
1
1
4
4
2
2
5
4
1
4
4
2
2
2
2
1
1
2
1
2
4
4
3
3
1
1
1
1
1
1
1
1
1
1
5
1
1
8
8
4
4
1
1
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
5.3
34
55
30
47
34
58
24
36
27
42
11.0
0.04
45
94
0.08
0.10
8.2
1.08
0.026
0.08
0.11
31
42
0.007
0.029
52
102
7.3
0.08
0.013
0.08
0.11
27
39
0.001
0.003
5.4
0.38
0.10
0.13
34
59
0.010
0.037
3.9
0.06
0.020
0.10
0.13
35
57
0.005
0.027
7.3
24
36
24
43
24
36
20
34
27
42
8.2
0.02
35
67
0.08
0.08
7.5
1.04
0.023
0.08
0.11
31
50
0.007
0.027'
53
95
6.0
0.03
0.011
0.08
0.10
28
37
0.001
0.003
5.4
0.30
0.10
0.14
29
46
0.007
0.032
4.5
0.08
0.019
0.10
0.11
33
57
0.006
0.040
5.8
25
39
28
41
25
38
20
38
27
40
8.1
0.03
34
62
0.07
0.09
6.1
0.79
0.024
0.09
0.11
27
45
0.007
0.025
52
106
7.2
0.02
0.011
0.07
0.09
26
37
0.001
0.003
4.2
1.15
0.11
0.12
30
45
0.007
0.025
3.7
0.06
0.018
0.08
0.14
29
49
0.005
0.029
5.9
22
34
24
39
22
32
18
31
26
39
6.4
0.02
31
52
0.07
0.08
7.7
1.00
0.026
0.08
0.10
28
44
0.007
0.031
46
75
6.2
0.01
0.011
0.06
0.10
27
39
0.001
0.005
3.9
1.22
0.11
0.12
25
38
0.006
0.026
3.2
0.05
0.018
0.09
0.10
26
41
0.004
0.023
5.1
20
30
26
44
21
36
18
37
28
44
6.9
0.02
30
53
0.07
0.09
7.6
1.05
0.026
0.08
0.11
29
49
0.006
0.029
43
86
5.3
0.01
0.012
0.07
0.10
27
36
0.001
0.004
3.7
0.33
0.09
0.12
25
43
0.005
0.018
4.0
0.04
0.017
0.08
0.10
26
45
0.003
0.018
aSS32E2S£E,T!S
6.5
23
33
23
33
22
33
15
34
29
49
6.2
0.02
28
47
0.07
0.09
7.3
1.03
0.027
0.08
0.11
27
43
0.005
0.025
39
55
4.4
0.01
0.010
0.08
0.09
26
35
0.001
0.004
4.3
0.12
0.10
0.11
27
44
0.005
0.028
4.5
0.03
0.017
0.08
0.12
28
42
0.004
0.032
7.8
21
34
24
49
23
43
14
26
25
42
5.3
0.02
22
36
0.07
0.08
6.0
0.65
0.027
0.09
0.13
27
45
0.004
0.019
39
77
4.9
0.01
0.011
0.07
0.09
24
31
0.002
0.004
5.3
0.07
0.09
0.12
22
35
0.004
0.018
3.0
0.05
0.017
0.08
0.11
27
49
0.004
0.025
4.5
22
34
23
36
20
30
16
28
24
40
6.4
0.02
21
35
0.07
0.09
5.3
1.04
0.024
0.10
0.12
27
40
0.003
0.011
31
50
4.5
0.01
0.011
0.07
0.09
25
37
0.002
0.005
3.3
0.06
0.10
0.11
25
41
0.005
0.024
1.9
0.03
0.017
0.10
0.10
25
38
0.004
0.028
3.6
17
27
23
37
20
34
19
29
23
39
5.7
0.02
23
36
0.07
0.09
5.0
0.59
0.028
0.09
0.12
26
44
0.003
0.011
31
50
3.8
0.01
0.012
0.07
0.10
23
31
0.001
0.004
3.8
0.08
0.09
0.12
25
41
0.005
0.019
2.0
0.03
0.016
0.08
0.12
24
38
0.004
0.028
3.4
17
27
21
33
27
43
17
28
24
41
5.2
0.03
21
33
0.07
0.09
4.9
0.93
0.029
0.09
0.12
25
41
0.003
0.011
31
50
3.1
0.01
0.011
0.07
0.10
26
36
0.001
0.004
3.0
0.08
0.10
0.12
25
41
0.005
0.018
2.1
0.03
0.016
0.08
0.11
27
41
0.004
0.022
APPENDIX A • DATA TABLES 167
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
MINNEAPOLIS-ST. PAUL, MN-WI
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOj ARITHMETIC MEAN
Oa 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO. ARITHMETIC MEAN
2ND MAX 24-HOUR
MOBILE, AL
O. 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PMm WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
MODESTO, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,8 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
MONMOUTH-OCEAN, NJ
CO 2ND MAX 8-HOUR
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
MONTGOMERY, AL
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
NASHUA, NH
CO 2ND MAX 8-HOUR
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PMIO WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
NASHVILLE, TN
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM1() WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOj ARITHMETIC MEAN
2ND MAX 24-HOUR
NASSAU-SUFFOLK, NY
CO 2ND MAX 8-HOUR
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
NEW BEDFORD, MA
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
Trend
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
NS
NS
UP
UP
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
NS
#Trend
Sites
3
3
1
4
4
8
8
8
8
2
2
4
4
1
1
1
1
1
1
1
2
2
2
1
1
1
1
1
1
2
1
2
2
3
3
3
3
3
5-
1
7
7
6
6
2
3
1
1
1
1
2
2
2
2
1
1
1
1
1989
9.0
0.38
0.017
0.07
0.09
28
46
0.004
0.021
0.07
0.09
31
42
0.008
0.064
11.8
0.04
0.027
0.09
0.11
46
91
6.1
0.11
0.14
0.08
0.10
23
35
6.2
0.022
0.07
0.09
20
34
0.008
0.040
7.4
0.63
0.012
0.08
0.10
37
58
0.011
0.062
6.5
0.029
0.11
0.15
27
54
0.010
0.045
0.09
0.12
23
34
1990
6.5
0.77
0.017
0.07
0.09
26
42
0.004
0.020
0.07
0.10
31
49
0.008
0.038
10.5
0.04
0.026
0.09
0.12
44
85
5.7
0.11
0.14
0.08
0.10
27
41
7.1
0.019
0.07
0.10
18
32
0.007
0.036
5.9
1.26
0.012
0.08
0.11
36
57
0.013
0.058
7.2
0.028
0.11
0.14
27
54
0.009
0.045
0.09
0.13
23
34
1991
7.2
0.31
0.016
0.07
0.08
25
40
0.004
0.021
0.08
0.07
32
49
0.009
0.050
9.4
0.04
0.024
0.10
0.11
48
101
5.5
0.11
0.15
0.08
0.09
26
44
6.9
0.016
0.08
0.10
19
34
0.005
0.024
5.0
1.06
0.010
0.09
0.10
35
52
0.012
0.062
6.6
0.029
0.11
0.18
27
54
0.009
0.039
0.10
0.13
20
35
1992
5.9
0.25
0.016
0.07
0.09
21
36
0.003
0.019
0.05
0.10
34
51
0.010
0.054
5.9
0.02
0.022
0.09
0.11
39
69
4.7
0.11
0.14
0.07
0.10
24
39
6.8
0.015
0.09
0.10
17
29
0.006
0.025
5.5
0.99
0.014
0.08
0.10
31
48
0.008
0.023
5.6
0.026
0.11
0.13
22
38
0.008
0.039
0.10
0.11
17
29
1993
5.2
0.12
0.018
0.08
0.08
21
33
0.003
0.015
0.07
0.09
32
51
0.010
0.066
6.6
0.02
0.024
0.08
0.11
40
72
5.3
0.09
0.13
0.08
0.11
23
34
5.2
0.016
0.08
0.11
16
28
0.006
0.022
6.4
0.89
0.012
0.08
0.10
31
47
0.010
0.047
5.6
0.026
0.09
0.13
23
42
0.008
0.033
0.09
0.09
17
24
1994
6.4
0.07
0.019
0.06
0.08
21
33
0.003
0.014
0.07
0.09
31
51
0.011
0.052
6.3
0.02
0.023
0.09
0.12
37
. 54
4.9
0.10
0.11
0.09
0.10
25
36
7.5
0.015
0.08
0.10
14
31
0.006
0.028
5.4
0.93
0.020
0.08
0.10
30
51
0.007
0.034
5.4
0.028
0.10
0.13
23
39
0.007
0.037
0.07
0.10
19
37
1995
6.0
0.23
0.017
0.07
0.10
22
38
0.002
0.012
0.07
0.11
29
43
0.009
0.053
5.4
0.01
0.022
0.09
0.13
34
68
3.8
0.08
0.15
0.08
0.10
26
43
6.8
0.014
0.08
0.10
13
25
0.005
0.023
4.8
1.78
0.014
0.08
0.10
31
50
0.005
0.026
5.0
0.025
0.09
0.15
19
33
0.005
0.030
0.08
0.14
14
21
1996
5.1
0.12
0.019
0.08
0.09
21
34
0.002
0.013
0.08
0.10
25
40
0.009
0.070
5.6
0.01
0.022
0.10
0.13
28
41
4.4
0.11
0.12
0.09
0.10
23
37
7.7
0.019
0.08
0.10
16
29
0.005
0.021
3.9
0.57
0.012
0.09
0.11
28
43
0.006
0.041
4.9
0.026
0.11
0.12
18
29
0.007
0.028
0.11
0.12
16
27
1997
4.5
0.09
0.017
0.07
0.09
21
32
0.002
0.013
0.08
0.11
26
45
0.008
0.049
4.2
0.01
0.021
0.09
0.11
30
48
3.7
0.09
0.13
0.08
0.09
24
40
4.7
0.016
0.08
0.11
17
29
0.006
0.025
4.7
0.63
0.012
0.09
0.11
28
47
0.006
0.048
4.7
0.025
0.09
0.14
20
34
0.006
0.029
0.09
0.12
18
29
1998
4.9
0.06
0.018
0.07
0.09
22
36
0.002
0.011
0.08
0.11
30
47
0.009
0.073
5.4
0.01
0.020
0.08
0.13
23
38
3.0
0.10
0.13
0.07
0.12
28
39
4.5
0.015
0.09
0.09
18
30
0.005
0.019
4.4
0.74
0.011
0.09
0.11
28
45
0.005
0.032
4.0
0.022
0.11
0.14
18
30
0.006
0.028
0.09
0.10
16
25
168 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 19S8
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
NEW HAVEN-MERIDEN, CT
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
S02 ARITHMETIC MEAN
2ND MAX 24-HOUR
NEW LONDON-NORWICH, CT-RI
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
NEW ORLEANS, LA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
N02 ARITHMETIC MEAN
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
NEW YORK, NY
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
NEWARK, NJ
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
NEWBURGH, NY-PA
J2£™^SEa3MSS3ESB«S533E£
Trend
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
NS
DOWN
DOWN
NS
NS
DOWN
NS
DOWN
NS
NS
DOWN
NS
DOWN
DOWN
• DOWN
NS
NS
NS
NS
NS
DOWN
DOWN
LEAD MAX QUARTERLY MEAN DOWN
NORFOLK-VIRGINIA BEACH-NEWPORT NEWS.VA-N
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
OAKLAND, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
N02 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
OKLAHOMA CITY, OK
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
#Trend 1989
Sites
1
2
2
6
6
2
2
1
1
2
2
1
1
2
1
2
6
6
1
1
2
2
5
1
2
5
5
12
12
7
7
3
4
2
2
3
3
4
4
2
3
1
3
3
3
3
2
2
6
4
2
8
8
4
4
3
3
2
1
3
4
4
4
4
0.028
0.10
0.15
32
51
0.012
0.071
0.12
0.14
23
39
0.008
0.027
6.1
0.09
0.017
0.08
0.10
31
49
0.003
0.017
7.7
0.12
0.044
0.09
0.12
34
56
0.015
0.060
7.6
0.030
0.09
0.12
35
59
0.012
0.047
1.42
5.2
0.020
0.08
0.10
27
43
0.007
0.033
4.9
0.13
0.022
0.07
0.10
32
56
0.002
0.013
5.2
0.04
0.013
0.08
0.10
23
38
1990 1991
0.027
0.10
0.13
30
49
0.010
0.045
0.12
0.16
21
35
0.008
0.029
4.9
0.05
0.016
0.08
0.10
27
44
0.003
0.013
7.1
0.16
0.043
0.09
0.13
31
52
0.014
0.054
7.1
0.029
0.09
0.13
31
55
0.010
0.040
1.01
4.5
0.019
0.08
0.10
26
38
0.007
0.025
4.8
0.08
0.021
0.07
0.09
31
56
0.002
0.011
4.5
0.04
0.012
0.08
0.10
22
36
0.028
0.10
0.16
33
58
0.010
0.055
0.11
0.14
24
40
0.007
0.027
4.2
0.03
0.015
0.08
0.10
26
48
0.004
0.023
6.7
0.12
0.043
0.10
0.14
29
46
0.014
0.048
8.3
0.028
0.10
0.12
30
52
0.010
0.035
0.66
5.1
0.020
0.09
0.10
26
42
0.007
0.022
4.8
0.10
0.022
0.06
0.09
33
63
0.002
0.010
3.9
0.04
0.011
0.08
0.10
22
35
1992 1993 1994 1995 1996 1997 1998
0.025
0.12
0.12
27
46
0.009
0.042
0.11
0.12
20
32
0.006
0.025
5.4
0.03
0.017
0.07
0.10
27
39
0.005
0.018
6.1
0.11
0.037
0.11
0.12
26
41
0.013
0.051
5.6
0.030
0.10
0.10
29
44
0.009
0.040
0.58
4.3
0.020
0.08
0.13
22
37
0.006
0.024
4.0
0.02
0.020
0.06
0.09
27
43
0.002
0.009
4.3
0.03
0.011
0.08
0.09
22
34
0.027
0.08
0.14
29
51
0.008
0.038
0.09
0.13
18
31
0.006
0.019
5.1
0.02
0.016
0.08
0.10
25
42
0.005
0.019
5.3
0.16
0.040
0.08
0.12
25
41
0.012
0.039
4.9
0.028
0.09
0.12
30
52
0.007
0.025
0.34
5.0
0.021
0.09
0.12
23
40
0.007
0.026
3.4
0.02
0.020
0.06
0.11
24
41
0.002
o.oio
5.2
0.02
0.011
0.07
0.09
21
34
0.030
0.09
0.14
29
52
0.008
.0.049
0.10
0.12
22
39
0.005
0.029
4.6
0.02
0.015
0.08
0.11
25
40
0.005
0.021
5.9
0.14
0.042
0.09
0.12
28
47
0.013
0.054
7.7
0.030
0.09
0.11
35
57
0.008
0.033
0.08
5.4
0.019
0.09
0.10
20
31
0.007
0.024
3.6
0.02
0.020
0.07
0.10
24
38
0.002
0.007
4.3
0.01
0.012
0.07
0.09
21
34
0.025
0.09
0.14
24
41
0.006
0.031
0.09
0.14
17
29
0.005
0.017
3.6
0.03
0.016
0.08
0.11
24
37
0.005
0.019
6.5
0.12
0.039
0.09
0.12
25
41
0.010
0.038
6.0
0.028
0.09
0.12
28
46
0.006
0.025
0.08
4.3
0.018
0.08
0.11
20
34
0.006
0.022
2.7
0.02
0.019
0.06
0.13
21
36
0.002
0.007
3.8
0.02
0.012
0.08
0.11
21
38
0.026
0.10
0.11
22
36
0.006
0.027
0.10
0.12
19
31
0.005
0.016
4.0
0.02
0.015
0.08
0.10
22
31
0.005
0.025
4.6
0.16
0.039
0.10
0.12
26
40
0.010
0.040
5.1
0.029
0.10
0.11
31
49
0.006
0.027
0.06
4.3
0.018
0.08
0.09
21
32
0.006
0.022
2.9
0.01
0.018
0.08
0.10
22
34
0.002
0.007
4.0
0.01
0.012
0.09
0.09
24
39
0.024 0.027
0.08 0.10
0.14 0.12
23 23
36 36
0.005 0.005
0.028 0.028
0.10 0.11
0.15 0.12
18 17
29 28
0.004 0.004
0.022 0.018
3.3 3.2
0.02 0.02
0.014 0.016
0.08 0.08
0.10 0.11
25 25
36 36
0.004 0.004
0.016 0.020
3.6 3.7
0.16 0.14
0.038 0.038
0.09 0.10
0.13 0.12
26 25
. 41 41
0.009 0.008
0.033 0.030
4.6 3.7
0.028 0.029
0.09 0.10
0.11 0.12
31 31
49 49
0.006 0.006
0.023 0.021
0.20 0.10
4.0 4.6
0.019 0.019
0.08 0.09
0.11 0.10
22 22
34 34
0.006 0.006
0.025 0.020
2.9 2.9
0.01 0.01
0.017 0.018
0.07 0.06
0.09 0.10
21 19
33 30
0.002 0.002
0.008 0.009
4.0 3.4
0.00 , 0.00
0.013 0.012
0.08 0.08
0.10 0.11
22 22
39 39
APPENDIX A • DATA TABLES 169
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
OLYMPIA.WA
PMu, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
OMAHA, NE-IA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ORANGE COUNTY, CA
CO 2ND MAX 8-HOUR
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY M AX 1 -HOUR
PM,a WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
ORLANDO, FL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOj ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PMia WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
OWENSBORO, KY
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM.,, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
PARKEHSBURG-MARIETTA, WV-OH
LEAD MAX QUARTERLY MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
PENSACOLA, FL
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
SOj ARITHMETIC MEAN
2ND MAX 24-HOUR
PEOR1A-PEKIN, IL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,a WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
PHILADELPHIA, PA-NJ
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,. WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
DOWN
NS
NS
DOWN
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
NS
NS
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
NS
NS
DOWN
NS
NS
NS
NS
DOWN
NS
DOWN
DOWN
#Trend
Sites
1
1
2
6
3
3
7
7
4
3
4
4
2
2
1
1
2
2
1
3
3
3
3
1
1
1
1
1
3
3
1
1
1
2
2
1
1
2
2
1
1
1
1
2
2
2
2
2
2
9
11
7
8
8
6
6
13
13
1989
28
74
4.8
0.94
0.07
0.08
42
64
9.0
0.038
0.12
0.21
45
72
0.002
0.008
4.3
0.02
0.013
0.09
0.11
27
36
0.002
0.006
0.014
0.08
0.10
31
49
0.010
0.053
0.04
0.09
0.12
0.016
0.076
0.08
0.09
0.007
0.057
7.7
0.04
0.08
0.10
28
46
0.007
0.046
7.1
1.25
0.027
0.10
0.13
35
60
0.011
0.043
1990 1991
24
44
5.2
0.84
0.07
0.07
37
63
8.3
0.039
0.12
0.17
45
75
0.002
0.008
4.5
0.01
0.012
0.09
0.11
27
37
0.002
0.011
0.011
0.08
0.11
29
45
0.009
0.038
0.02
0.09
0.11
0.014
0.064
0.08
0.11
0.008
0.078
7.4
0.04
0.08
0.08
27
45
0.007
0.055
4.9
1.63
0.025
0.10
0.13
32
57
0.010
0.039
25
43
5.8
0.75
0.06
0.08
36
59
7.0
0.038
0.11
0.18
41
68
0.002
0.007
3.6
0.00
0.012
0.08
0.09
27
35
0.002
0.007
0.011
0.09
0.09
29
45
0.009
0.044
0.02
0.08
0.12
0.014
0.060
0.09
0.10
0.006
0.056
6.3
0.02
0.07
0.10
26
43
0.008
0.065
4.6
1.69
0.025
0.10
0.14
35
60
0.009
0.034
1992
24
42
5.9
1.33
0.06
0.08
36
62
7.5
0.034
0.10
0.17
37
53
0.002
0.008
3.9
0.00
0.011
0.07
0.10
24
36
0.002
0.007
0.012
0.08
0.09
27
45
0.009
0.053
0.02
0.10
0.16
0.014
0.059
0.08
0.10
0.007
0.057
7.2
0.02
0.08
0.09
28
45
0.007
0.043
4.7
2.12
0.025
0.11
0.11
29
45
0.008
0.034
1993
24
49
5.3
1.29
0.06
0.06
31
48
5.8
0.032
0.10
0.15
36
57
0.002
0.006
3.8
0.00
0.012
0.08
0.10
24
33
0.002
0.011
0.012
0.08
0.11
25
45
0.009
0.050
0.02
0.08
0.11
0.014
0.065
0.09
0.10
0.005
0.032
7.3
0.03
0.07
0.08
22
37
0.007
0.039
4.7
2.18
0.025
0.09
0.13
30
51
0.008
0.031
1994
17
30
4.0
1.68
0.05
0.07
33
52
7.3
0.034
0.09
0.16
36
54
0.002
0.005
3.6
0.00
0.011
0.08
0.10
23
31
0.002
0.012
0.012
0.08
0.11
29
45
0.009
0.035
0.01
0.09
0.11
0.017
0.084
0.08
0.11
0.004
0.039
5.7
0.02
0.06
0.09
23
41
0.007
0.049
5.2
2.49
0.026
0.10
0.12
33
57
0.009
0.040
1995
17
35
5.5
1.03
0.06
0.08
30
52
5.7
0.033
0.10
0.12
41
68
0.003
0.005
3.3
0.00
0.010
0.08
0.10
22
32
0.002
0.006
0.013
0.09
0.11
27
48
0.007
0.028
0.02
0.09
0.12
0.010
0.041
0.09
0.12
0.003
0.019
5.6
0.03
0.08
0.09
22
40
0.007
0.084
4.1
1.56
0.025
0.09
0.13
30
52
0.007
0.028
1996
16
30
4.9
1.00
0.06
0.07
33
49
5.8
0.029
0.08
0.12
33
47
0.001
0.004
3.3
0.00
0.013
0.08
0.10
23
33
0.002
0.008
0.011
0.09
0.11
24
41
0.007
0.020
0.02
0.10
0.11
0.010
0.046
0.08
0.10
0.003
0.015
4.6
0.02
0.08
0.09
22
34
0.007
0.045
4.2
1.68
0.026
0.11
0.12
30
47
0.007
0.026
1997 1998
16 14
36 22
4.2 5.3
0.35 0.05
0.06 0.06
0.07 0.08
33 34
52 60
4.8 5.0
0.028 0.029
0.08 0.07
0.11 0.14
37 33
50 52
0.001 0.002
0.006 0.005
3.6 3.0
0.00 0.00
0.013 0.011
0.07 0.08
0.10 0.11
23 24
33 35
0.002 0.002
0.006 0.007
0.012 0.013
0.09 0.09
0.11 0.11
24 25
42 43
0.007 0.007
0.027 0.023
0.01 0.01
0.09 0.08
0.11 0.11
0.010 0.013
0.052 0.089
0.08 0.09
0.11 0.12
0.004 0.004
0.028 0.022
' 4.7 5.8
0.02 0.02
0.08 0.07
0.09 0.08
26 26
40 41
0.007 0.007
0.042 0.041
3.3 3.1
1.33 0.26
0.025 0.025
0.09 0.10
0.13 0.12
30 29
53 48
0.007 0.006
0.027 0.024
170 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14.
Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
PHOENIX-MESA, AZ
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
PINE BLUFF, AR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
PITTSBURGH, PA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
03 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
PITTSFIELD, MA
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PONCE, PR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
PORTLAND, ME
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
PORTLAND-VANCOUVER, OR-WA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
03 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
PORTSMOUTH-ROCHESTER, NH-ME
N02 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
PROVIDENCE-FALL RIVER-WARWICK, RI-MA
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
PROVO-OREM, UT
N02 ARITHMETIC MEAN
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
PUEBLO, CO
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
RACINE, Wl
CO 2ND MAX 8-HOUR
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
Trend
DOWN
DOWN
UP
NS
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
vs n a «M»Fas^j3*ig3r
#Trend
Sites
8
2
8
8
8
8
1
1
1
1
5
4
5
8
8
13
13
16
16
1
1
1
1
1
1
2
2
1
1
2
2
4
4
6
6
1
2
2
2
2
1
1
1
1
2
2
3
. 3
5
5
1
1
1
3
3
1
1
1
1
1
1989
7.6
0.09
0.07
0.10
49
73
0.002
0.006
27
44
5.3
0.12
0.023
0.09
0.11
35
62
0.017
0.072
0.08
0.09
46
73
0.10
0.13
27
44
0.010
0.039
8.2
0.07
0.06
0.09
25
45
0.015
0.09
0.12
21
34
0.008
0.029
6.2
0.024
0.09
0.12
31
48
0.010
0.043
0.028
0.07
0.11
49
95
33
55
6.4
0.11
0.14
1990 1991
6.7
0.09
0.07
0.11
43
66
0.003
0.011
21
39
5.6
0.09
0.023
0.09
0.10
33
61
0.016
0.071
0.08
0.11
38
60
0.10
0.13
25
39
0.010
0.034
8.5
0.06
0.06
0.12
25
42
0.015
0.09
0.11
20
33
0.007
0.025
7.3
0.024
0.09
0.13
29
44
0.009
0.039
0.025
0.07
0.09
32
55
26
43
5.5
0.11
0.11
6.2
0.11
0.08
0.10
43
66
0.005
0.013
19
30
4.3
0.09
0.023
0.08
0.11
34
59
0.015
0.058
0.09
0.10
30
47
0.09
0.14
26
44
0.009
0.032
9.1
0.06
0.08
0.09
26
43
0.015
0.08
0.14
19
36
0.007
0.021
7.4
0.025
0.09
0.14
30
48
0.008
0.039
0.022
0.07
0.08
42
91
30
46
5.7
0.09
0.14
1992 1993 1994 1995 1996 1997 1998
6.5
0.06
0.07
0.11
40
63
0.004
0.010
22
38
4.8
0.07
0.022
0.09
0.09
30
52
0.015
0.072
0.09
0.11
29
49
0.11
0.12
23
38
0.008
0.029
7.0
0.05
0.06
0.10
23
39
0.013
0.10
0.11
19
32
0.006
0.027
6.3
0.023
0.10
0.11
24
40
0.009
0.044
0.019
0.07
0.09
37
68
26
46
4.9
0.10
0.10
6.0
0.05
0.08
0.11
41
61
0.003
0.009
23
39
3.8
0.07
0.022
0.07
0.11
29
51
0.015
0.061
0.09
0.11
30
53
0.10
0.11
25
44
0.009
0.032
6.3
0.06
0.07
0.09
25
43
0.014
0.09
0.11
18
30
0.006
0.019
5.4
0.022
0.08
0.11
26
43
0.008
0.036
0.026
0.07
0.08
38
71
26
38
4.1
0.08
0.10
6.3
0.05
0.08
0.11
40
62
0.003
0.009
25
39
4.3
0.08
0.023
0.09
0.11
33
62
0.015
0.073
0.08
0.09
27
38
0.09
0.12
24
43
0.008
0.043
7.0
0.04
0.06
0.09
23
37
0.013
0.09
0.11
14
27
0.006
0.022
6.7
0.022
0.09
0.12
29
49
0.007
0.035
0.024
0.07
0.08
34
56
30
45
4.3
0.08
0.11
6.2
0.06
0.08
0.12
41
65
0.002
0.008
26
56
3.8
0.06
0.021
O.Q9
0.12
29
52
0.011
0.044
0.07
0.09
24
33
0.09
0.12
28
50
0.006
0.022
5.7
0.03
0.06
0.10
20
31
0.012
0.09
0.12
15
26
0.004
0.017
7.0
0.022
0.09
0.13
24
38
0.005
0.022
0.023
0.07
0.08
29
49
26
45
4.3
0.09
0.11
5.7
0.04
0.09
0.11
41
61
0.003
0.017
23
39
3.3
0.04
0.021
0.10
0.11
28
47
0.011
0.043
0.07
0.11
24
35
0.10
0.10
24
36
0.005
0.021
6.1
0.02
0.07
0.12
20
33
0.013
0.09
0.10
16
27
0.004
0.015
4.4
0.025
0.10
0.10
27
41
0.006
0.030
0.024
0.07
0.10
34
57
26
42
3.0
0.10
0.13
5.1 5.3
0.02 0.02
0.09 0.08
0.10 0.10
46 38
70 63
0.004 0.004
0.009 0.011
25 25
41 41
2.5 2.6
0.05 0.04
0.020 0.022
0.09 0.09
0.12 0.11
29 28
52 50
0.011 0.011
0.046 0.042
0.08 0.08
0.09 0.08
29 28
47 51
0.08 0.10
0.13 0.12
26 23
43 39
0.005 0.005
0.023 0.025
5.4 5.1
0.04 0.05
0.09 0.06
0.08 0.11
21 19
32 31
0.013 0.012
0.08 0.10
0.13 0.11
17 18
29 29
0.004 0.004
0.018 0.016
5.6 4.7
0.025 0.025
0.07 0.09
0.11 0.11
25 23
38 36
0.006 0.005
0.030 0.029
0.023 0.024
0.08 0.07
0.08 0.10
30 27
50 47
27 22
41 33
3.1 3.0
0.08 0.10
0.12 0.12
APPENDIX A • DATA TABLES 171
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
RALEIGH-DURHAM-CHAPEL HILL, NC
CO 2ND MAX 8-HOUR
Oa 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PMm WEIGHTED ANNUAL MEAN
90TH PERCENTILE
RAPID CITY, SD
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
READING, PA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO, ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
REDDING, CA
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,n WEIGHTED ANNUAL MEAN
90TH PERCENTILE
RENO, NV
CO 2ND MAX 8-HOUR
O. 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,o WEIGHTED ANNUAL MEAN
90TH PERCENTILE
RICHMOND-PETERSBURG, VA
CO 2ND MAX 8-HOUR
NO8 ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,o WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
RIVERSIDE-SAN BERNARDINO, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO. ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
ROANOKE.VA
N02 ARITHMETIC MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
ROCHESTER, MN
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ROCHESTER, NY
CO 2ND MAX 8-HOUR
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
ROCKFORD, IL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,» WEIGHTED ANNUAL MEAN
90TH PERCENTILE
Trend
DOWN
NS
NS
DOWN
NS
NS
NS
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
NS
DOWN
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
NS
NS
#Trend
Sites
1
1
1
2
2
2
2
1
10
1
2
2
2
2
1
1
1
1
5
4
4
6
6
2
1
4
4
3
3
1
1
7
4
7
15
15
11
11
4
4
1
1
1
2
2
1
1
1
1
2
2
2
2
2
2
2
1
1
2
2
1
1
1989
10.9
0.09
0.11
29
46
26
46
5.0
0.74
0.023
0.09
0.11
0.011
0.042
0.07
0.09
26
44
7.3
0.07
0.10
42
83
4.0
0.025
, 0.08
0.11
28
43
0.009
0.032
5.1
0.06
0.030
0.16
0.22
67
102
0.002
0.013
0.014
0.08
0.10
35
55
0.005
0.022
30
50
3.6
0.09
0.10
24
42
0.013
0.054
6.6
0.07
0.08
0.09
25
44
1990 1991
8.7 8.8
0.09 0.09
0.12 0.11
29 26
45 41
27 28
44 47
6.4 4.6
0.66 0.72
0.022 0.022
0.09 0.09
0.11 0.12
0.010 0.010
0.035 0.034
0.07 0.08
0.09 0.08
25 29
42 56
7.0 7.5
0.07 0.07
0.11 0.09
44 36
92 73
4.4 3.7
0.023 0.024
0.08 0.08
0.11 0.11
25 26
40 45
0.006 0.006
0.034 0.027
4.4 5.1
0.05 0.06
0.029 0.029
0.16 0.15
0.21 0.21
60 57
94 88
0.002 0.002
0.006 0.008
0.013 0.014
0.08 0.08
0.09 0.10
36 33
58 51
0.004 0.004
0.018 0.019
28 23
48 37
3.5 3.3
0.09 0.09
0.11 0.11
21 26
38 49
0.012 0.011
0.040 0.043
6.5 5.1
0.09 0.04
0.08 0.07
0.09 0.09
25 22
45 35
1992
7.3
0.09
0.10
24
36
25
40
4.6
0.62
0.020
0.10
0.10
0.009
0.033
0.07
0.08
25
45
5.9
0.07
0.08
36
64
2.5
0.023
0.09
0.12
22
36
0.005
6.024
3.6
0.03
0.027
0.15
0.20
47
76
0.002
0.009
0.013
0.08
0.09
32
48
0.004
0.016
21
37
3.5
0.10
0.09
22
38
0.011
0.039
4.6
0.06
0.08
0.09
21
31
1993
7.2
0.08
0.11
25
39
23
38
3.8
0.52
0.021
0.09
0.11.
0.009
0.033
0.07
0.07
20
37
5.0
0.07
0.09
40
71
3.9
0.024
0.09
0.12
23
43
0.007
0.023
3.5
0.04
0.028
0.14
0.18
46
78
0.002
0.006
0.014
0.07
0.10
35
56
0.004
0.018
20
31
3.2
0.08
0.09
23
40
0.010
0.041
4.3
0.03
0.08
0.08
16
26
1994
6.9
0.10
0.11
22
31
29
50
5.4
0.54
0.023
0.09
0.10
0.011
0.040
0.06
0.09
24
39
6.0
0.06
0.09
36
65
3.4
0.024
0.10
0.11
21
33
0.006
0.022
3.5
0.04
0.028
0.13
0.19
44
68
0.002
0.004
0.013
0.08
0.10
36
55
0.004
0.011
21
33
4.5
0.08
0.09
20
33
0.011
0.043
4.0
0.04
0.07
0.10
19
36
1995
6.6
0.08
0.10
23
34
24
41
3.9
0.37
0.021
0.08
0.11
0.009
0.033
0.08
0.09
20
34
4.4
0.07
0.08
32
52
2.6
0.022
0.09
0.11
23
38
0.005
0.016
3.4
0.04
0.029
0.14
0.18
44
• 71
0.002
0.005
0.013
0.08
0.09
34
54
0.003
0.010
20
32
3.2
0.08
0.11
21
37
0.010
0.038
4.5
0.03
0.08
0.10
19
39
1996
5.6
0.08
0.09
25
39
23
36
3.4
0.35
0.022
0.09
0.11
0.009
0.036
0.07
0.08
19
32
5.2
0.07
0.09
29
52
2.9
0.022
0.09
0.10
24
37
0.005
0.027
2.9
0.04
0.027
0.13
0.17
43
66
0.001
0.004
0.013
0.08
0.08
33
58
0.003
0.014
19
34
3.7
0.09
0.08
21
35
0.009
0.033
3.2
0.05
0.09
0.09
18
29
1997 1998
6.6
0.08
0.11
25
39
25
41
3.0
0.41
0.021
0.09
0.11
0.009
0.030
0.07
0.08
17
30
5.0
0.07
0.08
32
52
3.2
0.021
0.08
0.12
22
37
0.005
0.024
3.1
0.04
0.024
0.12
0.15
42
64
0.001
0.004
0.013
0.07
0.10
30
52
0.003
0.013
20
31
1.9
0.07
0.10
20
33
0.008
0.038
3.7
0.03
0.08
0.08
26
42
5.4
0.10
0.12
24
40
24
38
3.0
0.43
0.021
0.09
0.11
0.009
0.024
0.07
0.09
18
30
4.7
0.06
0.09
31
54
2.8
0.021
0.10
0.12
22
37
0.005
0.024
2.9
0.04
0.024
0.11
0.17
40
65
0.002
0.007
0.014
0.08
0.13
29
49
0.003
0.009
21
31
2.7
0.09
0.10
20
36
0.009
0.053
3.6
0.04
0.07
0.08
24
39
172 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
SACRAMENTO, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
ST. JOSEPH, MO
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
ST. LOUIS, MO-IL
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
SALINAS, CA
CO 2ND MAX 8-HOUR
NO2 ARITHMETIC MEAN
03 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SALT LAKE CITY-OGDEN, UT
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
SAN ANTONIO, TX
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SAN DIEGO, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTiLE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
SAN FRANCISCO, CA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NO2 ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO2 ARITHMETIC MEAN
2ND MAX 24-HOUR
Trend
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
#Trend
Sites
6
2
4
6
6
1
1
1
1
1
1
8
13
9
16
16
15
15
16
16
'' 1
1
3
3
1
1
1
2
2
2
2
6
6
3
3
2
1
2
2
3
3
8
3
7
9
9
3
3
3
3
4
1
1
3
3
1
1
1
1
1989
9.0
0.07
0.019
0.08
0.12
42
88
0.006
0.020
45
78
4.9
0.85
0.019
0.08
0.11
37
61
0.012
0.054
2.3
0.014
0.07
0.09
25
37
7.7
0.12
0.023
0.09
0.14
45
91
0.011
0.081
6.3
0.04
0.08
0.11
28
42
6.3
0.08
0.027
0.11
0.16
39
57
0.004
0.015
5.9
0.08
0.026
0.06
0.08
33
59
0.003
0.015
1990
8.9
0.10
0.018
0.08
0.13
42
88
0.006
0.010
40
71
4.3
0.76
0.018
0.08
0.11
33
54
0.011
0.042
2.5
0.012
0.07
0.08
23
39
6.8
0.08
0.019
0.09
0.11
33
56
0.009
0.039
5.4
0.07
0.08
0.10
25
40
5.6
0.09
0.025
0.11
0.15
34
54
0.004
0.015
5.7
0.04
0.021
0.06
0.06
28
59
0.002
0.010
1991
8.2
0.04
0.016
0.09
0.13
42
88
0.003
0.010
44
79
4.3
0.68
0.018
0.08
0.11
32
48
0.010
0.041
2.1
0.012
0.06
0.08
23
33
7.5
0.08
0.020
0.08
0.11
41
89
0.010
0.051
4.6
0.03
0.08
0.11
25
38
5.3
0.04
0.025
0.11
0.15
37
54
0.003
0.017
6.2
0.04
0.024
0.04
0.06
32
66
0.002
0.013
SSK.Mff3SKEt™>
1992
6.2
0.02
0.016
0.10
0.13
31
51
0.002
0.010
39
70
3.5
0.70
0.019
0.09
0.10
32
51
0.009
0.038
2.3
0.012
0.06
0.08
23
34
6.5
0.05
0.020
0.08
0.10
36
74
0.009
0.046
4.7
0.03
0.08
0.10
25
41
5.0
0.03
0.024
0.10
0.14
32
44
0.004
0.017
4.8
0.02
0.022
0.05
0.06
29
56
0.003
0.012
1993
6.4
0.05
0.017
0.10
0.12
29
54
0.001
0.003
32
56
3.5
0.57
0.018
0.08
0.11
28
46
0.009
0.040
2.1
0.012
0.06
0.08
22
35
6.4
0.07
0.024
0.07
0.10
37
68
0.007
0.043
5.1
0.03
0.07
0.11
23
40
4.4
0.03
0.020
0.09
0.13
30
46
0.002
0.009
4.6
0.03
0.024
0.05
0.08
27
39
0.002
0.010
Baas-iaaa&g-a
1994
6.2
0.02
0.015
0.09
0.11
30
49
0.001
0.004
34
62
3.8
0.66
0.019
0.07
0.12
31
50
0.009
0.040
2.0
0.012
0.07
0.08
20
29
5.9
0.05
0.023
0.08
0.11
32
53
0.004
0.013
3.5
0.03
0.08
0.11
23
38
4.7
0.02
0.021
0.09
0.11
31
42
0.003
0.013
4.3
0.02
0.022
0.05
0.07
25
47
0.001
0.005
1995
5.2
0.02
0.015
0.09
0.13
29
67
0.001
0.004
33
67
3.3
0.68
0.019
0.09
0.12
31
51
0.008
0.037
1.7
0.011
. 0.06
0.07
21
43
4.5
0.05
0.022
0.08
0.12
29
49
0.003
0.013
3.8
0.03
0.09
0.12
21
33
4.2
0.03
0.021
0.08
0.12
32
46
0.003
0.012
3.7
0.03
0.021
0.05
0.09
21
34
0.002
0.005
1996
4.9
0.01
0.015
0.10
0.12
25
40
0.001
0.003
32
52
3.4
0.67
0.019
0.09
0.11
27
43
0.008
0.038
2.4
0.011
0.06
0.08
20
34
6.2
0.03
0.023
0.08
0.11
33
61
0.003
0.014
4.8
0.02
0.09
0.12
19
27
4.3
0.02
0.019
0.08
0.10
28
38
0.004
0.015
3.9
0.01
0.022
0.06
0.08
21
32
0.002
0.007
1997
4.5
0.01
0.014
0.09
0.11
23
40
0.001
0.003
31
57
3.2
0.54
0.018
0.08
0.11
28
45
0.007
0.034
1.7
0.010
0.06
0.07
21
31
5.4
0.07
0.022
0.09
0.10
29
49
0.003
0.008
4.7
0.02
0.08
0.10
19
28
3.8
0.02
0.019
0.08
0.11
27
38
0.003
0.012
3.4
0.02
0.020
0.06
0.07
24
33
0.002
0.006
1998
4.5
0.01
0.015
0.08
0.13
23
40
0.001
0.004
26
47
3.4
0.43
0.019
0.08
0.11
30
49
0.006
0.034
1.9
0.010
0.06
0.07
18
29
4.9
0.06
0.022
0.08
0.12
27
46
0.003
0.008
4.8
0.02
0.08
0.10
19
28
3.5
0.01
0.018
0.08
0.11
23
36
0.003
0.011
3.5
0.01
0.020
0.05
0.06
22
34
0.002
0.006
APPENDIX A
DATA TABLES 173
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
Trend #Trend 1989 1990 1991 1992 1993 1994 1995 1996 19971998
Sites
WATERLOO-CEDAR FALLS, IA
PM,a WEIGHTED ANNUAL MEAN
90TH PERCENTILE
WAUSAU.WI
SOa ARITHMETIC MEAN
2ND MAX 24-HOUR
WEST PALM BEACH-BOCA RATON, FL
CO 2ND MAX 8-HOUR
NO, ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
WHEELING, WV-OH
CO 2ND MAX 8-HOUR
Oj 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOj ARITHMETIC MEAN
2ND MAX 24-HOUR
WICHITA, KS
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
Oj 4TH MAX 8-HOUR
2ND DAILY MAX 1 -HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
WILLIAMSPORT, PA
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,,, WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
WILMINGTON-NEWARK, DE-MD
CO 2ND MAX 8-HOUR
O, 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,. WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO, ARITHMETIC MEAN
2ND MAX 24-HOUR
WORCESTER, MA-CT
CO 2ND MAX 8-HOUR
NO, ARITHMETIC MEAN
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SOj ARITHMETIC MEAN
2ND MAX 24-HOUR
YAKIMA.WA
CO 2ND MAX 8-HOUR
PM,8 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
YOLO, CA
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM,0 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
YORK, PA
CO 2ND MAX 8-HOUR
LEAD MAX QUARTERLY MEAN
NOj ARITHMETIC MEAN
O3 4TH MAX 8-HOUR
2ND DAILY MAX 1-HOUR
PM10 WEIGHTED ANNUAL MEAN
90TH PERCENTILE
SO* ARITHMETIC MEAN
2ND MAX 24-HOUR
NS
DOWN
DOWN
NS
NS
NS
NS
NS
NS
NS
DOWN
NS
DOWN
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS -
NS
DOWN
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
NS
NS
NS
NS
1
1
1
. 1
1
1
2
2
2
2
1
1
1
1
1
2
2
3
3
3
5
2
2
4
4
1
1
1
1
1
1
1
1
1
2
2
2
2
1
1
2
2
1
1
1
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
35
57
0.004
0.030
3.7
0.013
0.06
0.10
19
27
0.003
0.009
5.2
0.08
0.11
34
59
0.021
0.065
7.9
0.03
0.07
0.07
30
50
0.07
0.08
29
46
0.007
0.042
4.5
0.10
0.12
33
52
0.016
0.048
7.9
0.026
26
37
0.011
0.040
8.7
33
62
0.08
0.10
46
81
4.6
0.05
0.022
0.09
0.10
31
50
0.008
0.035
35
57
0.004
0.030
2.7
0.014
0.06
0.09
19
27
0.002
0.007
7.1
0.08
0.11
30
50
0.020
0.064
5.9
0.02
0.07
0.10
28
49
0.07
0.09
26
50
0.006
0.025
5.4
0.10
0.14
30
48
0.013
0.043
6.0
0.022
23
41
0.008
0.034
7.4
33
62
0.08
0.10
46
81
4.4
0.05
0.022
0.09
0.12
30
56
0.007
0.023
35
57
0.004
0.030
' 3.1
0.012
0.07
0.08
18
28
0.002
0.012
5.6
0.08
0.11
31
53
0.020
0.074
5.9
0.02
0.08
0.09
31
51
0.07
0.10
31
60
0.007
0.025
4.0
0.10
0.14
28
45
0.012
0.033
7.2
0.023
21
38
0.009
0.029
9.0
40
81
0.08
0.11
46
81
3.7
0.05
0.021
0.10
0.11
32
60
0.008
0.020
34
63
0.004
0.024
3.7
0.011
0.06
0.07
20
30
0.003
0.010
5.6
0.09
0.10
30
52
0.018
0.077
5.6
0.01
0.08
0.08
32
53
0.08
0.09
24
36
0.007
0.029
4.1
0.11
0.12
24
39
0.013
0.046
8.0
0.024
20
34
0.007
0.033
8.8
32
60
0.07
0.11
35
63
3.6
0.05
0.020
0.10
0.10
27
44
0.007
0.034
31
48
0.004
0.039
3.1
0.013
0.05
0.12
19
29
0.004
0.028
4.1
0.08
0.11
29
51
0.018
0.075
5.0
0.01
0.07
0.08
31
56
0.07
0.09
24
47
0.006
0.025
3.8
0.09
0.14
25
43
0.013
0.041
6.1
0.028
20
37
0.007
0.025
7.9
35
63
0.09
0.09
29
62
3.3
0.04
0.022
0.08
0.11
31
52
0.008
0.032
29
45
0.004
0.024
2.8
0.012
0.08
0.08
18
25
0.003
0.016
4.6
0.08
0.10
28
49
0.015
0.065
4.9
0.01
0.06
0.09
26
50
0.08
0.08
28
52
0.006
0.042
4.3
0.09
0.12
29
52
0.012
0.044
5.9
0.025
20
36
0.008
0.024
8.0
29
55
0.08
0.10
30
46
3.9
0.04
0.024
0.09
0.12
32
51
0.009
0.041
36
52
0.003
0.022
2.8
0.012
0.07
0.08
18
25
0.002
0.019
5.0
0.08
0.10
28
46
0.010
0.055
5.2
0.01
0.07
0.10
27
51
0.07
0.09
28
49
0.006
0.027
4.6
0.09
0.14
28
45
0.010
0.036
4.2
0.021
19
32
0.006
0.023
7.1
24
46
0.08
0.11
30
61
2.7
0.04
0.021
0.08
0.10
30
56
0.006
0.020
32
48
0.003
0.015
2.5
0.012
0.06
0.09
18
28
0.002
0.014
3.5
0.09
0.11
28
42
0.011
0.058
5.8
0.01
0.07
0.09
25
43
0.07
0.08
25
36
0.006
0.028
3.6
0.12
0.11
25
42
0.009
0.035
5.3
0.019
20
34
0.005
0.021
7.4
30
59
0.08
0.11
24
40
2.8
0.07
0.021
0.09
0.10
28
46
0.007
0.022
31
47
0.002
0.013
3.6
0.012
0.06
0.08
20
29
0.002
0.013
3.1
0.09
0.11
24
41
0.010
0.043
4.8
0.01
0.07
0.09
22
40
0.07
0.09
26
40
0.008
0.028
4.5
0.08
0.12
25
43
0.008
0.034
3.4
0.019
20
32
0.004
0.021
7.4
32
59
0.09
0.09
25
37
3.4
0.04
0.019
0.08
0.11
31
49
0.009
0.026
30
47
0.003
0.031
2.5
0.012
0.06
0.10
20
31
0.001
0.004
3.5
0.08
0.10
25
46
0.011
0.045
4.8
0.01
0.08
0.10
24
41
0.08
0.10
26
40
0.005
0.021
3.1
0.09
0.12
24
41
0.007
0.027
3.5
0.019
19
33
0.005
0.017
7.4
26
43
0.07
0.11
22
42
2.4
0.05
0.019
0.09
0.11
31
49
0.008
0.023
178 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT,
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1989-1998 (continued)
Metropolitan Statistical Area
Trend
#Trend
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
Sites
YOUNGSTOWN-WARREN, OH
03 4TH MAX 8-HOUR NS 1
2ND DAILY MAX 1-HOUR NS 1
PM10 WEIGHTED ANNUAL MEAN DOWN 9
90TH PERCENTILE DOWN 9
SO2 ARITHMETIC MEAN DOWN 2
2ND MAX 24-HOUR NS 2
YUBA CITY, CA
O3 4TH MAX 8-HOUR NS 2
2ND DAILY MAX 1-HOUR NS 2
PM10 WEIGHTED ANNUAL MEAN DOWN 1
90TH PERCENTILE DOWN 1
0.08
0.09
39
60
0.09
0.11
34
55
0.016
0.043
0.09
0.10
31
53
0.016
0.053
0.08
0.12
33
55
0.016
0.048
0.10
0.10
29
49
0.013
0.056
0.09
0.10
27
49
0.011
0.063
0.08
0.10
29
49
0.011
0.051
0.08
0.11
28
48
0.010
0.038
0.10
0.10
26
39
0.009
0.044
0.09
0.10
25
43
0.008
0.037
0.08
0.11
27
47
0.008
0.030
0.08 0.08 0.08
0.10 0.10 0.11
39 39 34
60 73 57
0.09 0.08 0.08 0.09 0.09 0.07
0.11 0.10 0.11 0.11 0.09 0.10
30 34 33 29 29 23
59 51 68 50 48 44
CO
Pb
N02
O3 (1-hr) =
O3 (8-hr) =
so;° =
PPM
ug/m3 =
Highest second maximum non-overlapping 8-hour concentration (Applicable NAAQS is 9 ppm)
Highest quarterly maximum concentration (Applicable NAAQS is 1.5 yg/m3)
Highest arithmetic mean concentration (Applicable NAAQS is 0.053 ppm)
Highest second daily maximum 1-hour concentration (Applicable NAAQS is 0.12 ppm)
Highest fourth daily maximum 8-hour concentration (Applicable NAAQS is 0.08 ppm)
Highest second maximum 24-hour concentration (Applicable NAAQS is 150 pg/m3)
Highest second maximum 24-hour concentration (Applicable NAAQS is 0.14 ppm)
Units are parts per million
Units are micrograms per cubic meter
APPENDIX A • DATA TABLES 179
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-15. Number of Days with AQI Values Greater Than 100 at Trend Sites, 1989-1998,
and All Sites in 1998
#of
Metropolitan Statistical Area Trend
Sites
AKRON, OH
ALBANY-SCHENECTADY-TROY, NY
ALBUQUERQUE, NM
ALLENTOWN-BETHLEHEM-EASTON, PA
ATLANTA, GA
AUSTIN-SAN MARCOS, TX
BAKERSFIELD, CA
BALTIMORE, MD
BATON ROUGE, LA
BERGEN-PASSAIC, NJ
BIRMINGHAM, AL
BOSTON, MA-NH
BUFFALO-NIAGARA FALLS, NY
CHARLESTON-NORTH CHARLESTON, SC
5
7
21
9
7
5
7
15
6
8
16
25
21
9
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC 10
CHICAGO, IL
CINCINNATI, OH-KY-IN
CLEVELAND-LORAIN-ELYRIA, OH
COLUMBUS, OH
DALLAS, TX
DAYTON-SPRINGFIELD, OH
DENVER, CO
DETROIT, Ml
EL PASO, TX
FORT LAUDERDALE, FL
FORT WORTH-ARLINGTON, TX
FRESNO, CA
GARY, IN
GRAND RAPIDS-MUSKEGON-HOLLAND, M
GREENSBORO-WINSTON-SALEM-HIGH PT,
46
20
24
10
8
10
20
30
17
8
8
11
18
8
NC 7
GREENVILLE-SPARTANBURG-ANDERSON, SC 5
HARRISBURG-LEBANON-CARLISLE, PA
HARTFORD, CT
HONOLULU, HI
HOUSTON, TX
INDIANAPOLIS, IN
JACKSONVILLE, FL
JERSEY CITY, NJ
KANSAS CITY, MO-KS
KNOXVILLE, TN
LAS VEGAS, NV-AZ
LITTLE ROCK-NORTH LITTLE ROCK, AR
LOS ANGELES-LONG BEACH, CA
LOUISVILLE, KY-IN
MEMPHIS, TN-AR-MS
MIAMI, FL
MIDDLESEX-SOMERSET-HUNTERDON, NJ
MILWAUKEE-WAUKESHA, Wl
7
15
6
26
29
15
7
21
14
6
7
38
18
13
10
4
18
1989 1990
15 9
4 4
8 8
11 10
14 42
4 4
113 97
28 29
12 28
12 8
5 28
12 7
4 8
5 1
12 31
16 4
19 19
18 10
7 4
18 24
10 13
14 9
18 11
25 19
6 1
17 16
91 62
15 2
16 10
6 12
3 2
10 10
19 13
0 0
43 54
15 9
4 3
15 15
4 2
2 23
36 21
1 1
215 173
15 10
8 24
5 1
19 24
17 • 8
1991
30
9
5
14
23
3
109
50
11
11
5
13
9
2
12
22
22
23
17
2
12
6
28
7
0
20
83
8
26
5
3
21
23
0
37
12
0
25
11
10
8
3
169
15
9
1
24
24
1992
8
5
0
3
18
1
100
23
5
2
12
9
3
0
11
4
3
11
5
11
2
8
8
10
2
7
69
5
' 6
2
5
1
15
0
32
7
2
9
1
7
4
0
175
2
14
3
8
3
1993
10
5
0
6
30
2
97
48
5
3
10
6
1
2
23
3
13
13
7
12
11
3
5
7
4
9
59
0
3
20
9
15
14
0
28
9
3
19
4
20
6
2
134
20
15
6
13
4
1994
8
6
1
10
12
4
98
41
7
5
6
10
4
2
9
8
19
23
10
15
14
1
13
11
1
31
55
6
12
7
5
12
18
0
45
22
2
12
10
13
8
2
139
27
10
1
9
9
1995
12
3
0
17
33
12
104
36
15
11
32
8
6
1
13
21
23
24
15
36
11
2
14
5
1
28
61
17
17
6
8
13
14
0
66
19
1
16
22
20
1
7
113
21
21
2
16
14
1996 1997
11 6
4 3
0 0
6 13
21 26
0 0
109 55
28 30
7 8
3 5
15 8
2 8
3 1
3 3
18 26
6 9
11 11
17 11
16 8
12 15
18 9
0 0
13 12
7 3
1 0
14 14
70 75
11 12
7 8
6 13
7 10
3 9
5 16
0 0
28 47
13 12
1 4
5 9
10 18
19 36
5 0
1 1
94 60
10 13
19 17
1 3
8 18
5 4
1998
14
2
0
18
43
5
75
51
14
0
23
. 7
13
3
48
7
14
20
19
18
19
5
17
5
1
17
67
9
13
25
29
22
10
0
38
19
10
7
15
52
0
2
56
24
27
8
21
10
Total
#of
Sites
6
13
25
9
18
5
16
22
10
8
16
25
21
9
26
61
23
40
12
11
13
29
32
22
18
8
15
22
10
16
7
7
15
14
26
37
15
7
22
18
28
7
38
26
14
12
4
22
AQI
> 100
1998
14
2
0
18
60
6
78
51
21
0
23
9
13
3
51
10
20
22
23
36
21
9
17
8
1
' 17
69
10
19
30
29
22
10
0
40
22
10
7
15
55
11
3
56
29
27
8
22
12
180 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, A99S
Table A-15. Number of Days with AQI Values Greater Than 100 at Trend Sites, 1989-1998,
and All Sites in 1998 (continued)
Metropolitan Statistical Area
MINNEAPOLIS-ST. PAUL, MN-WI
MONMOUTH-OCEAN, NJ
NASHVILLE, TN
NASSAU-SUFFOLK, NY
NEW HAVEN-MERIDEN, CT
NEW ORLEANS, LA
NEW YORK, NY
NEWARK, NJ
#0f
Trend
Sites
24
3
17
4
10
11
29
12
NORFOLK-VA BEACH-NEWPORT NEWS.VA-NC 12
OAKLAND, CA
OKLAHOMA CITY, OK
OMAHA, NE-IA
ORANGE COUNTY, CA
ORLANDO, FL
PHILADELPHIA, PA-NJ
PHOENIX-MESA, AZ
PITTSBURGH, PA
PONCE, PR
PORTLAND-VANCOUVER, OR-WA
20
10
9
11
9
36
23
41
1
12
PROVIDENCE-FALL RIVER-WARWICK, RI-MA 1 1
RALEIGH-DURHAM-CHAPEL HILL, NC
RICHMOND-PETERSBURG, VA
RIVERSIDE-SAN BERNARDINO, CA
ROCHESTER, NY
SACRAMENTO, CA
ST. LOUIS, MO-IL
SALT LAKE CITY-OGDEN, UT
SAN ANTONIO, TX
SAN DIEGO, CA
SAN FRANCISCO, CA
SAN JOSE, CA
SAN JUAN-BAYAMON, PR
SCRANTON-WILKES-BARRE-HAZLETON, PA
SEATTLE-BELLEVUE-EVERETT, WA
SPRINGFIELD, MA
SYRACUSE, NY
TACOMA, WA
TAMPA-ST! PETERSBURG-CLEARWATER, FL
TOLEDO, OH
TUSCON, AZ
TULSA, OK
VENTURA, CA
WASHINGTON, DC-MD-VA-WV
WEST PALM BEACH-BOCA RATON, FL
WILMINGTON-NEWARK, DE-MD
YOUNGSTOWN-WARREN, OH
4
10
35
8
13
54
12
.7
23
9
8
10
11
16
13
6
7
22
6
20
11
12
32
6
5
9
1989 1990
8 4
15 21
12 31
14 20
11 17
4 6
29 36
21 23
4 8
6 4
4 4
1 1
56 45
9 4
44 39
30 12
21 19
0 0
2 11
9 13
14 15
11 6
187 158
5 5
63 36
25 23
21 5
3 4
127 96
0 0
18 7
0 0
6 9
6 9
10 13
2 1
3 5
4 6
8 3
2 1
5 16
87 70
24 25
1 0
12 9
8 3
1991
2
20
13
25
29
2
49
35
7
4
4
0
35
1
49
11
21
0
8
20
5
18
154
16
54
32
20
3
67
0
11
0
17
4
15
11
1
1
6
0
12
87
48
0
12
14
1992
3
6
6
5
10
5
10
10
8
3
2
0
35
4
24
13
9
0
6
5
0
8
174
2
44
15
9
1
66
0
3
0
3
3
12
2
2
1
2
1
1
54
14
0
7
5
1993 1994
0 4
11 3
18 21
15 10
17 14
6 8
19 21
13 13
19 6
4 3
2 5
1 1
25 15
4 3
51 26
16 10
13 19
0 0
0 2
7 7
11 2
30 13
168 149
0 1
14 30
1 9 32
5 13
3 4
58 46
0 0
4 2
0 0
10 7
0 3
13 , 12
4 0
0 2
1 3
7 9
1 1
4 12
37 63
48 20
3 0
10 5
2 0
1995
7
6
28
9
14
20
19
20
6
12
13
1
9
1
30
22 '
25 .
0
2
11
1
19
124
6
32
34
4
18
48
2
10
0
12
0
9
1
0
2
9
3
21
65
29
0
12
11
"TgtfiffiftliVTCiir
1996
1
12
23
6
8
8
15
12
4
11
2
1
9
1
22
17
11
0
6
4
1
5
119
0
30
20
8
3
31
0
' 7
1 '
4
6
5
0
1
3
11
0
14
62
18
0
3
5
1997
0
12
20
8
19
7
23
13
17
0
4
0
3
4
32
12
20
0
0
10
13
21
106
6
5
15
1
3
14
0
0
2
11
1
10
0
0
4
4
1
7
44
29
0
6
3
1998
0
19
30
10
10
•7
17
23
15
11
7
5
6
11
37
17
39
0
3
4
21
28
94
4
17
23
12
6
33
0
5
1
7
3
7
2
4
11
5
0
9
29
45
2
8
15
Total
#of
Sites
37
4
21
8
10
11
39
12
12
29
14
12
11
13
44
49
53
1
17
13
18
11
51
8
33
63
23
7
28
11
11
27
11
26
13
8
9
32
6
25
11
15
46
9
10
15
AQI
>100
1998
" ' "™>
31
32
11
10
7
21
23
15
12
7
5
g
14
38
37
39
0
3
5
40
28
96
4
33
24
19
6
35
0
8
1
7
3
7
3
4
11
8
0
9
30
47
2
28
22
APPENDIX A • DATA TABLES 181
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-16. (Ozone only) Number of Days with AQI Values Greater Than 100 at Trend Sites, 1989-1998,
and All Sites in 1998
Metropolitan Statistical Area
AKRON, OH
ALBANY-SCHENECTADY-TROY, NY
ALBUQUERQUE, NM
ALLENTOWN-BETHLEHEM-EASTON, PA
ATLANTA, GA
AUSTIN-SAN MARCOS, TX
BAKERSFIELD, CA
BALTIMORE, MD
BATON ROUGE, LA
BERGEN-PASSAIC, NJ
BIRMINGHAM, AL
BOSTON, MA-NH
BUFFALO-NIAGARA FALLS, NY
CHARLESTON-NORTH CHARLESTON, SC
#of
Trend
Sites
2
3
7
3
2
2
5
7
3
1
6
4
2
3
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC 3
CHICAGO, IL
CINCINNATI, OH-KY-IN
CLEVELAND-LORAIN-ELYRIA, OH
COLUMBUS, OH
DALLAS, TX
DAYTON-SPRINGFIELD, OH
DENVER, CO
DETROIT, Ml
EL PASO, TX
FORT LAUDERDALE, FL
FORT WORTH-ARLINGTON, TX
FRESNO, CA
GARY, IN
17
7
6
3
2
3
5
8
3
3
2
5
3
GRAND RAPIDS-MUSKEGON-HOLLAND, Ml 4
GREENSBORO-WINSTON-SALEM-HIGH PT
NC 2
GREENVILLE-SPARTANBURG-ANDERSON, SC 4
HARRISBURG-LEBANON-CARLISLE, PA
HARTFORD, CT
HONOLULU, HI
HOUSTON, TX
INDIANAPOLIS. IN
JACKSONVILLE, FL
JERSEY CITY, NJ
KANSAS CITY, MO-KS
KNOXVILLE, TN
LAS VEGAS, NV-AZ
LITTLE ROCK-NORTH LITTLE ROCK, AR
LOS ANGELES-LONG BEACH, CA
LOUISVILLE, KY-IN
MEMPHIS, TN-AR-MS
MIAMI, FL
3
3
1
10
6
2
1
6
4
3
2
14
4
4
4
MIDDLESEX-SOMERSET-HUNTERDON, NJ 1
MILWAUKEE-WAUKESHA, Wl
8
1988 1986
15 9
4 4
0 2
11 10
14 42
4 4
111 95
28 28
12 28
10 8
5 28
12 7
4 7
5 1
12 29
15 3
19 19
17 10
7 4
18 24.
10 13
5 4
18 11
5 6
6 1
17 16
89 56
15 2
16 10
4 12
3 2
10 10
18 13
0 0
43 54
15 9
4 3
15 15
4 2
2 23
2 2
•1 1
149 130
13 10
6 22
5 1
19 24
17 8
1990
30
9
0
14
23
3
107
50
11
11
5
13
9
1
12
22
22
23
17
2
12
0
28
1
0
20
81
8
26
5
3
21
21
0
37
11
0
25
11
10
0
3
126
15
9
1
24
24
1992
8
5
0
3
18
1
100
23
5
2
12
9
3
0
11
4
3
10
5
11
2
1
7
3
2
7
69
5
6
2
5
1
14
0
32
6
2
9
1
7
1
0
140
2
13
3
8
3
1992
10
5
0
6
30
2
97
48
5
3
10
6
1
2
23
3
13
12
7
12
11
0
5
3
4
9
59
0
3
20
9
15
14
0
28
9
3
19
3
20
2
2
112
19
13
6
13
4
1993
8
6
1
9
12
4
98
40
7
5
6
10
4
2
9
7
19
22
10
15
14
0
11
7
1
31
55
6
12
7
5
12
18
0
45
22
2
12
10
13
2
2
117
27
10
1
9
9
1999
12
3
, 0
17
33
12
104
36
15
11
32
8
6
1
13
21
23
21
15
36
11
0
12
5
1
28
61
17
17
6
8
13
13
0
66
19
1
16
22
20
0
7
97
21
21
2
16
14
1996 1996
11 6
4 3
0 0
6 13
21 26
0 0
109 55
28 30
7 8
3 5
15 8
2 8
3 1
3 3
18 26
6 9
11 11
17 11
16 8
12 15
18 9
0 0
12 12
2 1
1 0
14 14
70 75
11 11
7 8
6 13
7 10
3 9
5 16
0 0
28 47
13 12
1 4
5 9
9 18
19 36
2 0
1 1
74 45
10 13
18 17
1 3
8 18
5 4
1998
14
2
0
18
43
5
75
51
14
0
23
7
13
3
48
7
14
19
19
18
19
5
17
5
1
17
67
9
13
25
29
22
10
0
38
19
10
7
15
52
0
2
46
24
27
8
21
10
Total
#of
Sites
2
3
9
3
7
2
8
8
7
1
6
5
2
3
7
22
8
9
5
6
5
8
8
4
3
2
7
4
5
6
4
3
3
1
12
9
2
1
6
7
4
2
.14
7
4
4
2
9
AQI
>100
1998
14
2
0
18
60
6
76
51 .
21
0
23
9
13
3
51
10
20
21
23
36
21
9
17
6
1
17
69
10
19
30
29
22
10
0
40
22
10
7
15
54
3
2
• 46
29
27
8
22
12
182 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-16. (Ozone only) Number of Days with AQI Values Greater Than 100 at Trend Sites, 1989-1998,
and All Sites in 1998 (continued)
Metropolitan Statistical Area
MINNEAPOLIS-ST. PAUL, MN-WI
MONMOUTH-OCEAN, NJ
NASHVILLE, TN
NASSAU-SUFFOLK, NY
NEW HAVEN-MERIDEN, CT
NEW ORLEANS, LA
NEW YORK, NY
NEWARK, NJ
#of
Trend
Sites
4
1
7
1
2
6
5
2
NORFOLK-VA BEACH-NEWPORT NEWS,VA-NC 3
OAKLAND, CA
OKLAHOMA CITY, OK
OMAHA, NE-IA
ORANGE COUNTY, CA
ORLANDO, FL
PHILADELPHIA, PA-NJ
PHOENIX-MESA, AZ
PITTSBURGH, PA
PONCE, PR
PORTLAND-VANCOUVER, OR-WA
8
4
3
4
3
8
8
8
0
4
PROVIDENCE-FALL RIVER-WARWICK, RI-MA 2
RALEIGH-DURHAM-CHAPEL HILL, NC
RICHMOND-PETERSBURG, VA
RIVERSIDE-SAN BERNARDINO, CA
ROCHESTER, NY
SACRAMENTO, CA
ST. LOUIS, MO-IL
SALT LAKE CITY-OGDEN, UT
SAN ANTONIO, TX
SAN DIEGO, CA
SAN FRANCISCO, CA
SAN JOSE, CA
SAN JUAN-BAYAMON, PR
SCRANTON-WILKES-BARRE-HAZLETON,
SEATTLE-BELLEVUE-EVERETT, WA
SPRINGFIELD, MA
SYRACUSE, NY
TACOMA, WA
TAMPA-ST. PETERSBURG-CLEARWATER
TOLEDO, OH
TUSCON, AZ
TULSA, OK
VENTURA, CA
WASHINGTON, DC-MD-VA-WV
WEST PALM BEACH-BOCA RATON, FL
WILMINGTON-NEWARK, DE-MD
YOUNGSTOWN-WARREN, OH
1
4
15
2
6
16
2
2
g
3
4
0
PA 4-
2
4
1
1
FL 6
3
6
3
5
12
2
1
1
1989
1
15
10
14
11
4
24
20
4
6
4
0
43
9
42
4
14
0
0
9
10
11
180
5
30
21
14
3
122
0
7
0
6
0
10
0
0
4
8
0
5
87
23
1
12
8
1990
1
21
31
20
15
6
33
22
8
4
4
1
38
4
39
7
11
0
8
13
15
6
153
5
17
23
5
4
96
0
4
0
9
7
13
0
4
6
3
1
16
70
25
0
9
3
1991
0
20
13
25
28
2
47
32
7
3
4
0
35
1
49
7
20
0
3
20
5
18
152
16
44
32
3
3
67
0
5
0
17
3
15
11
0
1
6
0
12
87
48
0
12
14
1992
2
6
6
5
10
5
10
10
8
3
2
0
35
4
24
11
8
0
6
5
0
8
172
2
43
15
0
1
66
0
3
0
3
3
12
2
2
1
2
1
1
54
14
0
7
5
1993 1994
0 0
11 3
18 21
15 10
13 13
6 8
19 21
13 12
19 6
4 3
2 5
0 0
25 15
4 3
51 25
16 7
13 19
0 0
0 1
7 7
11 2
30 13
167 148
0 1
14 30
9 31
2 4
3 4
58 46
0 0
4 2
0 0
10 7
0 3 ,
13 12
4 0
0 2
1 3
7 9
1 1
4 12
37 63
48 20
3 0
10 5
2 0
1995
4
6
28
9
14
20
18
20
6
12
13
0
8
1
30
19
24
0
2
11
1
19 •
119
6
32
34
4
18
48
2
10
0
12
0
9
1
0
2
9
3
21
65
29
0
12
11
1996 1997
1 0
12 12
23 20
6 8
8 19
8 7
15 23
12 13
4 17
11 0
2 4
0 0
9 3
1 4
22 32
17 10
11 20
0 0
6 0
4 10
1 13
5 21
116 102
0 6
30 5
20 14
6 1
3 3
31 14
0 0
7 0
0 0
4 11
6 1
4 10
0 0
1 0
3 4
11 4
0 1
14 7
62 43
18 29
0 0
3 6
5 3
Mgtm~r -iv'.j -.sys-
1998
0
19
30
10
10
7
17
23
15
11
7
0
6
11
37
17
39
0
3
4
21
28
94
4
17
23
12
6
33
0
5
0
7
3
7
2
4
11
5
0
9
29
45
2
8
15
Total
#of
Sites
5
2
7
2
2
6
7
2
3
9
4
3
4
4
10
18
11
0
4
3
8
4
19
2
12
17
7
2
10
3
6
1
4
4
4
2
2 .
7
3
6
3
7
17
2
4
3
AQI
> 100
1998
1
31
32
11
10
7
21
23
15
12
7
0
6
14
37
33
39
0
3
5
40
28
96
4
33
24
, 19
6
35
0
8
0
7
3
7
3
4
11
6
0
9
30
47
2
28
22
APPENDIX A • DATA TABLES 183
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-17. Condensed Nonattainment Areas List(a)
1
z
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
State
AK
AK
AK
AL
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AZ
AZ
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA
CO
CO
CO
CO
CO
CO
CO
CO
CO
CO
CT
DC-MO-VA
GA
GU
GU
ID
ID
ID
ID
IL-IN
IN
KY
KY-IN
Area Name(b) O3
Anchorage
Fairbanks
Juneau
Birmingham 1
Ajo
Bullhead City
Douglas
Miami-Hayden
Morenci
Nogales
Paul Spur
Payson
Phoenix 1
Riltito
San Manuel
Yuma
Imperial Valley
Los Angeles-South Coast Air Basin 1
Mono Basin (in Mono Co.)
Owens Valley
Sacramento Metro 1
San Diego 1
San Francisco-Oakland-San Jose 1
San Joaquin Valley 1
Santa Barbara-Santa Maria-Lompoc 1
Searles Valley
Southeast Desert Modified AQMA 1
Ventura Co. 1
Aspen
Canon City
Colorado Springs
Denver-Boulder
Fort Collins
Lamar
Longmont
Pagosa Springs
Steamboat Springs
Telluride
Greater Connecticut 1
Washington 1
Atlanta 1
Piti Power Plant
Tanguisson Power Plant
Bonner Co.(Sandpoint )
Fort Hall I.R.
Portneuf Valley
Shoshone Co.
Chicago-Gary-Lake County 1
Marion Co. (Indianapolis)
Boyd Co. (Ashland)
Louisville 1
Pollutant(c)
CO S02 PM10
1 . 1
1
1
1 1
1
1 1
2 1
1
1
1
1
1 . 1
1
1
1
1
1 . 1
1
1
1
1
1
2
1
1
1
1 . 1
1
1
1 . .
1
1
. . 1
1
1
1
1
1
1
2
1 3
1
Population(d)
Pb N02 03 CO S02 PM10
222 . 170
. . .30
12
751 ..
• . . 6 6
5
13 13
3 3
. ' . . .8
19
1
8
2,092 2,006 . 2,122
0
5
54
92
13,000 13,000 . 13,000
0
18
1,639 . . 1,041
2,498
5,815
2,742 . . 2,742
370 . .
30
384 . . 349
669 ..
5
12
353
. 1,800 . 1,836
106
8
52
. . 1
6
. . ... 1
2,470 . 126
3,923
2,653
0
.0
26
1
74
13
7,887 . 475 625
1 . ...
51
834 ..
Pb All
222
30
12
751
6
5
13
3
8
19
1
8
. 2,122
0
5
54
92
. 13,000
-0
18
. 1,639
. 2,498
. 5,815
. 2,742
370
30
384
669
5
12
353
. 1,836
106
8
52
1
6
1
. . 2,470
. 3,923
. 2,653
0
0
26
1
74
13
. 7,887
16 16
51
834
184 DATA TABLES • APPENDIX A
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-17. Condensed Nonattainment Areas List(a) (continued)
State
52 LA
53 MA
54 MD
55 MD
56 MN
57 WIN
58 MO
59 MO
60 MO-IL
61 MT
62 MT
63 MT
64 MT
65 MT
66 MT
67 MT
68 MT
69 MT
70 MT
71 MT
72 MT
73 NE
74 NM
75 NM
76 NM
77 NV
78 NV
79 NV
80 NY-NJ-CT
81 OH
82 OH
83 OH
84 OH
85 OH
86 OH-KY
87 OR
88 OR
89 OR
90 OR
91 OR
92 OR
93 OR
94 PA
95 PA
96 PA
Area Name(b) O3
Baton Rouge 1
Springfield (W. Mass) 1
Baltimore 1
Kent and Queen Anne Cos. 1
Minneapolis-St. Paul
Olmsted Co. (Rochester)
Dent
Liberty-Arcadia
St. Louis 1
Butte
Columbia Falls
Kalispell
Lame Deer
Lewis & Clark (E. Helena)
Libby
Missoula
Poison
Ronan
Thompson Falls
Whitefish
Yellowstone Co. (Laurel)
Douglas Co. (Omaha)
Anthony
Grant Co. - - .
Sunland Park 1
Central Steptoe Valley
Las Vegas
Reno .
New York-N. New Jersey-Long Island 1
Cleveland-Akron-Lorain
Coshooton Co.
Gallia Co.
Jefferson Co. (Steubenville)
Lucas Co. (Toledo)
Cincinnati-Hamilton 1
Grants Pass
Klamath Falls
LaGrande
Lakeview
Medford
Oakridge
Springfield-Eugene
Lancaster 1
Pittsburgh-Beaver Valley 1
Warren Co
Pollutant(c)
CO S02 PM10
1 . 1
1
1
1
1
1
1
1
1 . . 1
1
1
1
1
1
1
1
1
1 . 1
1 . 1
1 . 1
2 1
1
1
1
1
1 . 1
1 . 1
1
1
1 .1
1
1
2 1
2
97 PA-DE-NJ-MDPhiladelphia-Wilmington-Trenton 1 . . .
98 PA-NJ
99 PR
100 TN
101 TX
102 TX
Allentown-Bethlehem
Guaynabo Co.
Shelby Co. (Memphis)
Beaumont-Port Arthur 1
Dallas-Fort Worth . 1
1
1
Population(d)
Pb NO2 O3 CO SO2 PM,0
559 ..
812 ..
2,348 .
52 ..
. 2,310 . 272
71
1 . . . .
1 ....
1 . 2,390
33
3
. .• . 12
. . 1
1 . . . 2 .
3
43 .43
. . . . . 3
2
1
3
5
1 . ....
2
28
8 . .
2
258 . 741
. .134 . 254
17,943 12,338 . 1,488
. 1,683 1,412
35
31
4
. . . .462
1,705
17 . 17
18 . 18
12
3
62 . 63
3
157
423 ...
2,468 . 446 '75
22
6,010
.91
85
1 . ...
361 ..
1 . 3,561
Pb All
559
812
. 2,348
52
. 2,310
71
3 3
2 2
2 2,390
33
3
12
1
2 2
3
43
3
2
1
3
5
. 1 1
2
28
8
2
741
254
. 17,943
. 1,683
35
31
4
462
. 1,705
17
18
12
3
63
3
157
423
. 2,468
22
. 6,010
91
85
826 826
361
264 3,561
APPENDIX A • DATA TABLES 185
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-17. Condensed Nonattainment Areas List(a)
State
103 TX
104 TX
105 UT
106 UT
107 UT
108 UT
109 WA
110 WA
111 WA
112 WA
113 WA
114 Wl
115 Wl
116 Wt
117 W!
118 WV
119 WV
120 WV
121 WY
Area Name(b) O3
El Paso 1
Houston-Galveston-Brazoria 1
Ogden
Salt Lake City
Tooele Co.
Utah Co. (Provo)
Olympia-Tumwater-Lacey
Seattle-Taooma
Spokane
Wallula
Yaktma
Manitowoc Co. 1
Marathon Co. (Wausau)
Milwaukee-Racine 1
Oneida Co. (Rhinelander)
Follansbee
New Manchester Gr. (in Hancock Co) .
Wier.-Butler-Clay (in Hancock Co)
Sheridan
32
Pollutant(c)
CO SO2 PM10
1 . 1
1 . 1
1 1
1
1 . 1
1
3
1 . 1
1
1
1
1
1
1
1 1
1
20 31 77
Population(d)
Pb NO2 O3 CO SO2 PM10
592 54 . 515
3,731
63 . 63
.725 725
26
85 . 263
63
730
279 . 177
47
54
80 ..
. 115
1,735
31
3
10
25 22
13
8 0 92,505 33,230 4,371 29,804
Pb All
592
. 3,731
63
725
26
263
63
730
279
47
54
80
115
. 1 ,735
31
3
10
25
13
1,116 105,106
Notes:
(a) This Is a simplified listing of Classified Nonattainment areas. Unclassified and Section 185a nonattainment areas are not included. In certain cases,
(ootnotes are used to clarify the areas involved. For example, the lead nonattainment area listed within the Dallas-Fort Worth ozone nonattainment area is
in Frisco, Texas, which is not in Dallas county, but is within the designated boundaries of the ozone nonattainment area. Readers interested in more
detailed information should use the official Federal Register citation (40 CFR 81).
{b) Names of nonattainment areas are listed alphabetically within each state. The largest city determines which state is listed first in the case of multiple-city
nonattainment areas. When a larger nonattainment area, such as ozone, contains 1 or more smaller nonattainment areas, such as PM10 or lead, the
common name for the larger nonattainment area is used. Note that several smaller nonattainment areas may be inside one larger nonattainment area, as
is the case In Figure A-1. For the purpose of this table, these are considered one nonattainment area and are listed on one line. Occasionally, two
nonattainment areas may only partially overlap, as in Figure A-2. These are counted as two distinct nonattainment areas and are listed on separate lines.
(o) The number of nonattainment areas for each of the criteria pollutants is listed.
(d) Population figures were obtained from 1990 census data. For nonattainment areas defined as only partial counties, population figures for just the
nonattainment area were used when these were available. Otherwise, whole county population figures were used. When a larger nonattainment area
encompasses a smaller one, double-counting the population in the "All" column is avoided by only counting the population of the larger nonattainment area.
(e) Lead nonattainment area is a portion of Franklin township, Marion county, Indiana.
(() Sulfur dioxide nonattainment area is a portion of Boyd county.
(g) Lead nonattainment area is Herculaneum, Missouri in Jefferson county.
(h) Lead nonattainment area is a portion of Lewis and Clark county, Montana.
(i) Ozone nonattainment area is a portion of Dona Ana county, New Mexico.
(j) Lead nonattainment area is a portion of Shelby county, Tennessee.
(k) Lead nonattainment area is Frisco, Texas, in Collin county.
186 DATA TABLES • APPENDIX A
-------
NATIONAL AIR DUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-17. Condensed Nonattainment Areas List(a) (continued)
J NAforOS
)NAforSO2
Figure A-1. (Multiple NA areas within a larger NA
area) Two SO2 areas inside the Pittsburgh-Beaver
Valley ozone NA. Counted as one NA area.
Figure A-2. (Overlapping NA areas) Searles Valley
PM10 NA partially overlaps the San Joaquin Valley
ozone NA. Counted as two NA areas.
APPENDIX A
DATA TABLES 187
-------
r
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Table A-18. Trend in 8-hr ozone concentrations at National Park and National Monument sites, 1989-98
National Park
Acadia NP
Big Bend NP
Brigantine
Cape Cod NS
Cape Remain
Chiricahua NM
Cong area Swamp
Cowpens NB
Denali NP
Everglades NP
Glacier NP
Grand Canyon NP
Great Smoky Mtn
Great Smoky Mtn
Lassen Volcanic
Mammoth Cave NP
Olympic NP
Pinnacles NM
Rocky Mountain
Saguaro NM
Sequoia/Kings C
Shenandoah NP
Theodore Roosevelt
Yosamite NP
Notes:
Trend 1989 1990
NS 0.076 0.089
2 4
UP nd nd
nd nd
NS 0.102 0.109
13 17
NS 0.104 0.097
10 9
UP 0.064 nd
1 nd
NS 0.066 0.069
0 0
UP nd nd
nd nd
UP 0.081 0.074
1 0
UP 0.046 0.048
0 0
NS 0.067 0.060
0 0
NS 0.056 0.050
0 0
NS 0.065 0.072
0 0
UP 0.083 0.092
2 5
UP 0.079 0.087
0 4
NS 0.073 0.078
0 1
NS 0.084 0.083
2 2
NS 0.044 0.046
0 0
NS 0.080 0.083
1 3
UP 0.067 0.057
0 0
NS 0.072 0.075
0 0
NS 0.093 0.096
29 27
UP 0.072 0.086
0 4
NS 0.065 0.062
0 0
NS 0.085 0.094
4 19
1991
0.095
7
0.057
0
0.111
34
0.111
16
0.06
0
0.071
0
0.059
0
0.078
1
0.049
0
0.060
0
0.051
0
0.073
0
0.079
2
0.082
1
0.066
0
0.078
0
0.043
0
0.084
3
0.076
0
0.073
0
0.097
34
0.083
3
0.060
0
0.080
1
1992
0.080
1
0.061
0
0.094
8
0.096
6
0.072
0
0.065
0
0.067
0
0.086
4
0.05
0
0,061
0
0.051
0
0.074
0
0.088
5
0.075
0
0.069
0
0.073
0
0.046
0
0.084
3
0.071
0
0.074
1
0.102
50
0.077
1
0.057
0
0.084
3
1993
0.080
3
0.063
0
0.093
13
0.088
4
0.069
0
0.068
0
0.063
0
0.082
3
0.048 .
0
0.064
0
0.044
0
0.066
0
0.088
4
0.089
7
0.064
0
0.072
0
0.042
0
0.060
0
0.071
1
0.082
1
0.106
48
0.083
2
0.055
0
0.078
0
1. The trends statistic is the annual fourth highest daily maximum 8-hour ozone concentration (ppm)
1994
0.075
0
0.069
0
0.083
2
0.088
4
0.067
0
0.071
0
0.064
0
0.083
2
0.049
0
0.064
0
0.055
0
0.073
0
0.093
10
0.088
6
0.078
1
0.075
1
0.042
0
0.078
0
0.076
0
0.080
0
0.106
58
0.083
2
0.057
0
0.077
0
1995
0.092
5
0.065
0
0.1
10
0.105
9
0.075
1
0.059
0
0.076
1
0.084
3
0.053
0
0.058
0
nd
nd
nd
nd
0.099
11
0.093
12
0.074
0
0.088
5
0.049
0
0.083
3
0.076
0
0.083
2
0.095
18
0.087
7
0.058
0
0.084
2
1996
0.073
2
0.073
0
0.095
13
0.096
8
0.071
1
0.072
0
0.074
0
0.080
2
0.053
0
0.063
0
0.057
0
0.073
0
0.088
8
0.092
12
0.073
1
0.082
2
0.046
0
0.094
9
0.072
0
0.076
0
0.105
50
0.081
1
0.059
0
0.081
1
1997
0.077
1
0.063
0
0.106
18
0.1
17
0.082
3
0.065
0
0.065
0
0.091
6
0.051
0
0.066
0
0.040
0
0.072
0
0.098
19
0.095
20
0.067
0
0.078
1
0.045
0
0.076
1
nd
nd
0.079
0
0.097
26
0.089
6
0.071
0
nd
nd
1998
nd
nd
0.07
0
0.091
22
0.084
2
0.076
0
0.067
0
0.081
0
0.096
15
0.054
0
0.072
0
0.053
0
0.072
0
0.11
35
0.106
34
0.078
1
nd
nd
0.046
0
0.088
5
0.080
1
0.077
0
0.094
26
0.107
22
inc
0
nd
nd
. The number of exceedances of the level of the 8-hour
ozone NAAQS Is shown below the concentration value.
2. "nd" indicates no data available for that year.
3. Inc" Indicates less than 90 days of monitoring data available for that year.
4. *NS" indicates no statistically significant trend (at the 0.05 level).
5, "UP" Indicates a statistically significant upward trend in ozone concentrations.
188 DATA TABLES • APPENDIX A
-------
APPENDIX B
Methodology
http://wwwJepa.gov/oar/aqtrnd98/appendb.pdf
AIRS Methodology
The ambient air quality data present-
ed in Chapters 2 and 3 of this report
are based on data retrieved from AIRS
on July 14,1999. These are direct mea-
surements of pollutant concentrations
at monitoring stations operated by
state and local governments through-
out the nation. The monitoring sta-
tions are generally located in larger
urban areas. EPA and other federal
agencies also operate some ah- quali-
ty monitoring sites on a temporary
basis as a part of air pollution re-
search studies. The national monitor-
ing network conforms to uniform
criteria for monitor siting, instrumenta-
tion, and quality assurance.1/2
In 1999, 4,369 monitoring sites
reported air quality data for one or
more of the six NAAQS pollutants to
AIRS, as seen in Table B-l. The geo-
graphic locations of these monitoring
sites are displayed in Figures B-l to
B-6. The sites are identified as Na-
tional Air Monitoring Stations
(NAMS), State and Local Air Moni-
toring Stations (SLAMS), or "other."
NAMS were established to ensure a
long-term national network for urban
area-oriented ambient monitoring
and to provide a systematic, consis-
tent data base for air quality compari-
sons and trends analysis. SLAMS
allow state or local governments to
develop networks tailored for their
immediate monitoring needs.
"Other" monitors may be Special
Purpose Monitors, industrial moni-
tors, tribal monitors, etc.
Table B-1. Number of Ambient Monitors
Reporting Data to AIRS
# of Sites
: Reporting # of
: Data to Trend Sites
Pollutant AIRS in 1998 1989-1998
CO 511 363
Pb 306 189
NO2 422 225
O3 1,048 661
PM10 1,436 934
SO2 646 482
Total 4,369 2,854
Air quality monitoring sites are
selected as national trends sites if
they have complete data for at least
eight of the 10 years between 1989 and
1998. The annual data completeness
criteria are specific to each pollutant
and measurement methodology.
Table B-l displays the number of
sites meeting the 10-year trend com-
pleteness criteria. Because of the
annual turnover of monitoring sites,
the use of a moving 10-year window
maximizes the number of sites avail-
able for trends and yields a data base
that is consistent with the current
monitoring network.
The air quality data are divided
into two major groupings: daily
(24-hour) measurements and continu-
ous (1-hour) measurements. The
daily measurements are obtained
from monitoring instruments that
produce one measurement per
24-hour period and typically operate
on a systematic sampling schedule of
once every six days, or 61 samples
per year. Such instruments are used
to measure PMj0 and lead. More
frequent sampling of PM10 (every
other day or every day) is also com-
mon. Only PM10 weighted (for each
quarter to account for seasonality)
annual arithmetic means that meet
the AIRS annual summary criteria are
selected as valid means for trends
purposes.3 Beginning in 1998, some
sites began reporting PM10 data
based on local conditions, instead of
standard, or "reference," conditions.
For these sites, PM10 statistics were
converted from local conditions to
standard conditions to ensure all
PM10 data in this report are consistent
and reflect standard conditions.4
Only lead sites with at least six
samples per quarter in three of the
four calendar quarters qualify as
trends sites. Monthly composite lead
data are used if at least two monthly
samples are available for at least
three of the four calendar quarters.
Monitoring instruments that oper-
ate continuously produce a measure-
ment every hour for a possible total
of 8,760 hourly measurements in a
APPENDIX B • AIRS METHODOLOGY 189
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure B-1. Carbon monoxide monitoring program, 1998.
NAMS
SLAMS
Other
Figure B-2. Lead monitoring program, 1998.
190 AIRS METHODOLOGY • APPENDIX B
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure B-3. Nitrogen dioxide monitoring program, 1998.
NAMS
SLAMS
Other
Figure B-4. Ozone program, 1998.
NAMS
SLAMS
Other
APPENDIX B • AIRS METHODOLOGY 191
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure B-5. PM10 monitoring program, 1998.
,.-*** %
Figure B-6. Sulfur dioxide monitoring program, 1998.
192 AIRS METHODOLOGY • APPENDIX B
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
Figure B-7. Class I Areas in the IMPROVE Network meeting data completeness
criteria.
IMPROVE Sites
D Complete for Trends Only
x Complete for 1998 Only
a Complete for Both
year. For hourly data, only annual
averages based on at least 4,380
hourly observations are considered
as trends statistics. The SQ2
standard-related daily statistics re-
quire at least 183 daily values to be
included in the analysis. Ozone sites
meet the annual trends data com-
pleteness requirement if they have at
least 50 percent of the daily data
available for the ozone season, which
varies by state, but typically runs
from May through September.5
Air Quality Trend Statistics
The air quality statistics presented in
this report relate to the pollutant-
specific NAAQS and comply with the
recommendations of the Intra-Agen-
cy Task Force on Air Quality Indica-
tors.6 .A composite average of each
trend statistic is used in the graphical
presentations throughout this report.
All sites were weighted equally in
calculating the composite average
trend .statistic. Missing annual sum-
mary statistics for the second through
ninth years for a site are estimated by
linear interpolation from the sur-
rounding years. Missing end points
are replaced with the nearest valid
year of data. The resulting data sets
are statistically balanced, allowing
simple statistical procedures and
graphics to be easily applied. This
procedure is conservative since end-
point rates of change are dampened
by the interpolated estimates.
IMPROVE Methodology
Data collected from the Interagency
Monitoring of Protected Visual Envi-
ronments (IMPROVE) network is
summarized in Chapters 2 (PM2 5
section) and 6 of this report. The
completeness criteria and averaging
method used to summarize the IM-
PROVE data are slightly different
from those used for the criteria pol-
. lutants. (Data handling guidance is
currently being developed for the
IMPROVE network. Future summa-
ries will be based on this guidance.)
The source data sets are available on
the public FTP site. The PM2.5 data
were obtained from Dr. James Sisler
of Colorado State University. The
visibility data were obtained from
ftp://alta_vista.cira.colostate.edu/. .
DATA/IMPROVE/Trends 88-98/10-
50-90/TREND98.LIS.
The annual average statistics in
these files were used to assess trends
in this report. The IMPROVE data
are not reported in terms of a calen-
dar year. The IMPROVE year runs
from March to February of the fol-
lowing year. It follows that the four
seasons are: March to May (spring),
June to August (summer), September
to November (autumn), and December
to the following February (winter). The
network samplers monitor on
Wednesdays and Saturdays through-
out the year, yielding 104 samples
per year and 26 samples per season.
Sites were required to have data at
least 50 percent of the scheduled
samples (13 days) for every calendar
quarter.
IMPROVE monitoring sites are
selected as trends sites if they have
complete data for at least eight of the
10 years between 1989 and 1998 or
(six of seven years for those who
began monitoring in 1992). A year is
valid only if there are at least 13
samples (50 percent complete) per
season for both measured and recon-
structed PM2.5. The same linear inter-
.polation applied to the criteria
pollutants is applied here. In all,-.34
IMPROVE sites met the data com-
pleteness criteria. They are denoted
in Figure B-7 with a square or a
. square with an X.
For consistency, the same sites are
used in both the PM2.s section and
the Visibility chapter. The exception.
is Washington D.C., which is not
APPENDIX B • AIRS METHODOLOGY 193
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
State-supplied MOBILE model in-
puts for 1990,1995, and 1996 were
used, as well as state-supplied VMT
data for 1990. Rule effectiveness
from pre-1990 chemical and allied
product emissions was removed.
Lead content of unleaded and leaded
gasoline for the on-road and
non-road engine lead emission esti-
mates was revised, and Alaska and
Hawaii nonutility point and area
source emissions from several
sources were added. Also, this report
incorporates data from CEMs col-
lected between 1994 and 1998 for
NOX and SO2 emissions at major
electric utilities.
All of these changes are part of a
broad effort to update and improve
emissions estimates. Additional
emissions estimates and a more de-
tailed description of the estimation
methodology are available in two
companion reports, the National Air
Pollutant Emission Trends, 1900-1998
and the National Air Pollutant Emis-
sion Trends Procedures Document,
References
1. Clean Air Act Amendments of
1990, U.S. Code, volume 42, section
7403 (c){2), 1990.
2. Ambient Air Quality Surveillance,
44 CFR 27558, May 10,1979.
3. Aerometric Information Retrieval
System (AIRS), Volume 2, U.S. Envi-
ronmental Protection Agency, Office of
Air Quality Planning and Standards,
Research Triangle Park, NC, October,
1993.
4. Falke, S. and Husar, R. (1998) Cor-
rection of Particulate Matter Concen-
trations to Reference Temperature and
Pressure Conditions, Paper Number
98-A920, Air & Waste Management
Association Annual Meeting, San Di-
ego, CA, June 1998.
5. Ambient Air Quality Surveillance,
51 FR 9597, March 19,1986.
6. U.S. Environmental Protection,
Agency Intra-Agency Task Force Re-
port on Air Quality Indicators,
EPA-450/4-81-015, U.S. Environmental
Protection Agency, Office of Air Quali-
ty Planning and Standards, Research
Triangle Park, NC, February 1981.
7. Rosenbaum, A. S., Stiefer, M. P.,
and Iwamiya, R. K. November, 1999.
Air Toxics Data Archive and AIRS Com-
bined Dataset: Contents Summary Report.
SYSAPP-99/26d. Systems Applications
International, San Rafael, CA.
8. In most cases, four non-missing
quarterly means are available after
applying the GLM method, so that the
resulting annual mean is the arithmetic
mean of the four quarterly averages. In
some cases, a quarter was incomplete
for all the sites in the database so that
no filled-in quarterly mean would be
available for that quarter. Seasonal
averaging was thus employed to deal
with this situation in a reasonable
manner.
9. Cohen, J.P. and A. K. Pollack. 1990.
General Linear Models Approach to Esti-
mating National Air Quality Trends As-
suming Different Regional Trends.
SYSAPP-90/102. Systems Applications
International, San Rafael, CA.
10. National Air Pollutant Emission
Trends, 1900-1998, EPA-454/R-00-002,
U.S. Environmental Protection Agency,
Office of Air Quality Planning and
Standards, Research Triangle Park, NC,
February 2000.
11. National Air Pollutant Emission
Trends Procedures Document,
1900-1998, EPA-454/R-00-001, U.S.
Environmental Protection Agency,
Office of Air Quality Planning and
Standards, Research Triangle Park, NC,
February 2000.
196 AIRS METHODOLOGY • APPENDIX B
-------
TECHNICAL REPORT DATA
(PLEASE READ INSTRUCTIONS ON THE REVERSE BEFORE COMPLETING)
1. REPORT NO.
EPA-454/R-00-003
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1998
5. REPORT DATE
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
L. AUTRY, R. DAMBERG, C. DAVIS, T. FITZ-SIMONS, N. FRANK, P. FRECHTEL, W.
FREAS, J. HEMBY, G. LEAR, D. MINTZ, M. SCHMIDT, R. THOMPSON, M. WAYLAND
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR AND RADIATION
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
RESEARCH TRIANGLE PARK, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT ' —
THIS REPORT PRESENTS NATIONAL TRENDS IN AIR QUALITY FOR CARBON MONOXIDE, LEAD NITROGEN
DIOXIDE, OZONE, PARTICULATE MATTER, AND SULFUR DIOXIDE. TRENDS ARE PRESENTED FOR THE
LONG TERM (WHEN AVAILABLE). FOR THE 10 YEAR PERIOD FROM 1989 TO 1998, AND FOR THE SHORT
TERM (CHANGES OVER THE PAST YEAR). IN ADDITION TO AIR QUALITY TRENDS FROM DATA COLLECTED
AT MONITORING STATIONS ACROSS THE COUNTRY, TRENDS IN ANNUAL NATIONWIDE EMISSIONS ARE
ALSO PRESENTED.
WHILE THE POLLUTANTS NAMED ABOVE ARE EMPHASIZED IN THIS REPORT, RELATED TOPICS ARE ALSO
INCLUDED. THESE INCLUDE VISIBILITY, ACID DEPOSITION, AIR TOXICS, NON-ATTAINMENT AREAS, AND
TRENDS IN METROPOLITAN STATISTICAL AREAS. THE REPORT ALSO CONTAINS A SUBSTANTIAL
APPENDIX OF DATA TABLES.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS ~~
ACID DEPOSITION, VISIBILITY, AIR TOXICS, AIR POLLUTION
TRENDS, POLLUTANT STANDARDS INDEX (PSI) PARTICULATE
MATTER, EMISSIONS TRENDS, AIR QUALITY STANDARDS,
NON-ATTAINMENT AREAS, CARBON MONOXIDE, LEAD, OZONE
NITROGEN DIOXIDE, SULFUR DIOXIDE.
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI FIELD/GROUP
8. DISTRIBUTION STATEMENT
UNLIMITED
UNCLASSIFIED
21. NO. OF PAGES
UNCLASSIFIED
22. PRICE
-------
-------
|