United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA 454/R-01-004
March 2001
Air
&EPA National Air Quality and
Emissions Trends Report, 1999
1999 Annual Mean PM Concentrations (ug/m3)
6
r>>"k
/SlBi ) /^-^^
wj
w w~ • 0 O~/ / w-"^~N-fc=fc^ x.
Tj
^ kJt
Data Completeness
o < 4 quarters
O One or more quarters with < 11 samples
O All quarters with at least 11 samples
O All quarters 75% or more complete
Puerto Rico
Concentration
• >20
O 15-20
• 10-15
• 0-10
Source: US EPAAIRS Data base as of 7/12/00 without data flagged as 1, 2, 3,4, T, W, Y, or X.
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EPA454/R-01-004
National Air Quality and
Emissions Trends Report,
1999
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 2001
Printed on recycled paper.
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About the Cover
The map on the cover depicts nationwide annual mean PM2.5 concentra-
tions from the Federal Reference Method (FRM) monitoring network, as
well as information on data completeness. Annual mean concentrations
are generally above the level of the 1997 standard of 15 ug/m3 in much of
the eastern United States and throughout California. Annual mean con-
centrations above 20 ug/m3 are seen in several major metropolitan areas
including Pittsburgh, Cleveland, Atlanta, Chicago, and St. Louis and Los
Angeles The western Great Plains and mountain regions show notably
low annual mean concentrations, most below 10 ug/m3.
Data Source: U.S. EPA AIRS Data Base 1/30/01.
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, Office of
Radiation and Indoor Air 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.
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Preface
This is the 27th 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/.
MI
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IV
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Contents
Chapter 1
Executive Summary 1
Chapter 2 2
Chapters 2
Chapter 4 3
Chapters 3
Chapter 6 4
Chapter 7 6
References and Notes 7
Chapter 2
Criteria Pollutants — National Trends 9
Carbon Monoxide 11
Lead 17
Nitrogen Dioxide 23
Ozone 29
Particulate Matter 40
Sulfur Dioxide 61
References 67
Chapter 3
Criteria Pollutants — Metropolitan Area Trends 69
Status: 1999 69
Trends Analysis 70
The Air Quality Index 70
Summary of AQI Analyses 72
References and Notes 74
Chapter 4
Criteria Pollutants — Nonattainment Areas 75
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Chapter 5
Air Toxics 79
Background 79
Health and Environmental Effects 79
National Air Toxics Control Program 80
Air Toxics Emissions in 1996 82
Trends in Air Toxics Emissions 84
Ambient Monitoring 84
Trends In Ambient Concentrations 85
National Atmospheric Deposition Program/Mercury Deposition Network 96
Integrated Atmospheric Deposition Network 96
References 97
Chapter 6
Visibility Trends 99
Introduction 99
Nature and Sources of the Problem 100
Long-Term Trends (1981-1995) 102
Recent Trends (1990-1999) from IMPROVE Data 103
Regional Visibility Trends for the Eastern and Western United States 104
The Components of PM Contributing to Trends in Visibility Impairment 105
Current Visibility Conditions 109
Programs to Improve Visibility 113
References 114
Chapter 7
Atmospheric Deposition of Sulfur and Nitrogen Compounds 115
Primary Atmospheric Deposition Monitoring Networks 116
National Atmospheric Deposition Network/National Trends Network 116
Trends Analyses for Sulfate and Nitrogen Concentrations in Wet Deposition 117
Clean Air Status and Trends Network 118
Dry Deposition 119
Concentration Trends Analysis at CASTNet Sites 119
Seasonal Trends in SO2 Emissions and Related Air Quality 122
Sulfur and Nitrogen Deposition 124
References 125
Appendix A
Data Tables 127
Appendix B
Methodology 229
AIRS Methodology 229
Emissions Estimates Methodology 233
IMPROVE Methodology 234
Air Toxics Methodology 234
References 237
VI
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Figures
Figure 2-1. Trend in 2nd maximum non-overlapping 8-hour average CO concentrations, 1980-1999 11
Figure 2-2. Trend in 2nd maximum non-overlapping 8-hour average CO concentrations by type of location, 1980-1999 12
Figure 2-3. Trend in CO 2nd maximum non-overlapping 8-hour concentrations by EPA region, 1980-1999 12
Figure 2-4. CO emissions by source category, 1999 13
Figure 2-5. Density map of 1999 carbon monoxide emissions, by county. 13
Figure 2-6. Trend in national total CO emissions, 1980-1999 14
Figure 2-7. Highest 2nd maximum non-overlapping 8-hour average CO concentration by county, 1999 15
Figure 2-8. Trend in maximum quarterly average Pb concentrations (excluding point-source oriented sites), 1980-1999 18
Figure 2-9. Pb maximum quarterly mean concentration trends by location (excluding point-source oriented sites), 1980-1999 18
Figure 2-10. Trend in Pb maximum quarterly mean concentration by EPA region, 1980-1999 19
Figure 2-11. National total Pb emissions trend, 1980-1999 20
Figure 2-12. Pb emissions by source category, 1999 20
Figure 2-13. Pb maximum quarterly concentration in the vicinity of Pb point sources, 1999 21
Figure 2-14. Highest Pb maximum quarterly mean by county, 1999 21
Figure 2-15. Trend in annual NO2 mean concentrations, 1980-1999 24
Figure 2-16. Trend in annual mean NO2 concentrations by type of location, 1980-1999 24
Figure 2-17. Trend in NO2 maximum quarterly mean concentration by EPA region, 1980-1999 25
Figure 2-18. Trend in national total NOX emissions, 1980-1999 26
Figure 2-19. NOX emissions by source category, 1999 26
Figure 2-20. Density map of 1999 nitrogen dioxide emissions, by county. 27
Figure 2-21. Highest NO2 annual mean concentration by county, 1999 28
Figure 2-22. Trend in annual 2nd-highest daily maximum 1-hour, and 4th-highest daily 8-hour O3 concentrations, 1980-1999 30
Figure 2-23. Trend in 4th-highest daily 8-hour O3 concentrations, 1980-1999 31
Figure 2-24. Trend in 2nd highest daily 1-hour O3 concentration by EPA region, 1980-1999 32
Figure 2-25. Trend in 4th highest daily 8-hour O3 concentration by EPA region, 1980-1999 32
Figure 2-26. Trend in annual 2nd-highest daily maximum 1-hour O3 concentrations by location, 1980-1999 33
Figure 2-27. Comparison of actual and meteorologically adjusted 1-hour O3 trends, 1980-1999 33
Figure 2-28. Areas with PAMS networks 34
Figure 2-29. A comparison of the median change in summer morning concentrations of the most abundant VOC species measured
at all PAMS sites and PAMS type 2 sites from 1995 and 1999 34
Figure 2-30. Trend in 4th-highest daily 8-hour O3 based on 34 CASTNet sites in the rural eastern United States, 1980-1999 35
Figure 2-31. Trend in annual 4th-highest daily maximum 8-hour O3 concentrations in National Parks, 1980-1999 35
Figure 2-32. Trend in national total anthropogenic VOC emissions, 1980-1999 36
Figure 2-33. Anthropogenic VOC emissions by source category, 1999 36
Figure 2-34. Density map of 1999 VOC emissions, by county. 38
Figure 2-35. Highest second daily maximum 1-hour O3 concentration by county, 1999 38
Figure 2-36. Highest fourth daily maximum 8-hour O3 concentration by county, 1999 39
Figure 2-37. Trend in annual mean PMi0 concentrations, 1990-1999 42
Figure 2-38. PMW annual mean concentration trends by location, 1990-1999 42
Figure 2-39. National PMi0 emissions trend, 1980-1999 (traditionally inventoried sources only) 43
Figure 2-40. PMM emissions from traditionally inventoried source categories, 1999 43
VII
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Figure 2-41. Total PMW emissions by source category, 1999 44
Figure 2-42. PMW emissions density by county, 1999 45
Figure 2-43. Trend in PMi0 annual mean concentration by EPA region, 1990-1999 45
Figure 2-44. Highest 2nd maximum 24-hour PMW concentration by county, 1999 46
Figure 2-45. Status of PM25 monitor network, as of May 2001 47
Figure 2-46. 1999 annual mean PM25 concentrations (}ig/m3) 48
Figure 2-47. 1999 98th percentile 24-hour average PM25 concentrations (jag/mS) 48
Figure 2-48. Urban PM25 monthly patterns by region, 1999 49
Figure 2-49. Rural PM25 monthly patterns by region, 1999 50
Figure 2-50. Class I Areas in the IMPROVE Network meeting the data completeness criteria in Appendix B 51
Figure 2-51. Annual mean PM25 concentrations in 1999 52
Figure 2-52. PM25 concentrations, 1992-1999 at eastern IMPROVE sites meeting trends criteria 52
Figure 2-53. PM25 concentrations, 1990-1999 at western IMPROVE sites meeting trends criteria 53
Figure 2-54. PM25 concentrations, 1990-1999 at the Washington D.C. IMPROVE site 53
Figure 2-55. PM25 ambient composition 55
Figure 2-56. PM25 emission sources 56
Figure 2-57. Direct PM25 emissions density by county, 1999 57
Figure 2-58. National direct PM25 emissions trend, 1990-1999 (traditionally inventoried sources only) 58
Figure 2-59. Direct PM25 emissions from traditionally inventoried source categories, 1999 58
Figure 2-60. Total direct PM25 emissions by source category, 1999 59
Figure 2-61. National ammonia emissions by principle source categories, 1999 59
Figure 2-62. Estimated 1999 annual mean PMi0-2.5 60
Figure 2-63. Estimated 1999 98th percentile 24-hour average PM10-2.5 developed from 1999 FRM monitor data 60
Figure 2-64. Trend in annual mean SO2 concentrations, 1980-1999 62
Figure 2-65. Annual mean SO2 concentration by trend location, 1980-1999 62
Figure 2-66. National total SO2 emissions trend, 1980-1999 63
Figure 2-67. SO2 emissions by source category, 1999 63
Figure 2-68. Long-term ambient SO2 trend, 1980-1999 64
Figure 2-69. Trend in SO2 annual arithmetic mean concentration by EPA region, 1980-1999 65
Figure 2-70. Plants affected by the Acid Rain Program 65
Figure 2-71. Highest 2nd maximum 24-hour SO2 concentration by county, 1999 66
Figure 3-1. Air Quality Index logo 72
Figure 3-2. Number of days with AQI values > 100, as a percentage of 1990 value 73
Figure 3-3. Percent of days over 100 due to ozone 73
Figure 4-1. Location of nonattainment areas for criteria pollutants, September 2000 75
Figure 4-2. Classified ozone nonattainment areas 76
Figure 5-1. National contribution of source types to 1996 NTI emissions for the 188 HAPs 82
Figure 5-2. National contribution of source types to 1996 NTI emissions for the urban HAPs 82
Figure 5-3. National contribution by emission source type for individual urban HAPs and diesel particulate matter, 1996 83
Figure 5-4. Urban/rural splits by source type for the 1996 national emissions of 188 HAPs 84
Figure 5-5. Urban/rural splits by source type for the 1996 national emissions of 33 urban HAPs 84
Figure 5-6. Change in national air toxics emissions - baseline (1990-1993) to 1996 85
Figure 5-7. Locations for urban and rural air toxics monitors with long-term data 86
Figure 5-8a. National trend in annual average benzene concentrations in metropolitan areas, 1994-1999 88
Figure 5-8b. National trend in annual average 1,3-butadiene concentrations in metropolitan areas, 1994—1999 88
Figure 5-8c. National trend in annual average total suspended lead concentrations in metropolitan areas, 1994—1999 89
Figure 5-8d. National trend in annual average perchloroethylene concentrations in metropolitan areas, 1994-1999 89
Figure 5-8e. National trend in annual average styrene concentrations in metropolitan areas, 1994-1999 90
Figure 5-8f. National trend in annual average toluene concentrations in metropolitan areas, 1994—1999 90
Figure 5-9a. Trend in annual average benzene concentrations for metropolitan sites in California, 1990-1999 92
VIM
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Figure 5-9b. Trend in annual average 1,3-butadiene concentrations for metropolitan sites in California, 1990-1999 92
Figure 5-9c. Trend in annual average total suspended lead concentrations for metropolitan sites in California, 1990-1999 93
Figure 5-9d. Trend in annual average perchloroethylene concentrations for metropolitan sites in California, 1990-1999 93
Figure 5-9e. Trend in annual average styrene concentrations for metropolitan sites in California, 1990-1999 94
Figure 5-9f. Trend in annual average toluene concentrations for metropolitan sites in California, 1990-1999 94
Figure 6-1. IMPROVE sites meeting data completeness requirements for sites operating in 1999 100
Figure 6-2. Comparison of the three visibility metrics (extinction, deciview and visual image) 101
Figure 6-2a. Images of Shenandoah National Park and Yosemite National Park 101
Figure 6-3. Shenandoah National Park on clear and hazy days and the effect of adding 10 jig/mS of fine particles to each 102
Figure 6-4. Long-term trends for 75th percentile light extinction coefficient from airport visual data (July-September) 103
Figure 6-5a. Visibility trends for 10 eastern U.S. Class I areas for clearest, middle, and haziest 20 percent days in the
distribution, 1992-1999 104
Figure 6-5b. Visibility trends for 26 western U.S. Class I areas for clearest, middle, and haziest 20 percent days in the distribution,
1992-1999 104
Figure 6-6a. Aerosol light extinction in 10 eastern Class I areas for the clearest 20 percent of the days in the distribution, 1992-1999. 105
Figure 6-6b. Aerosol light extinction in 10 eastern Class I areas for the middle 20 percent of the days in the distribution, 1992-1999. 105
Figure 6-6c. Aerosol light extinction in 10 eastern Class I areas for the haziest 20 percent of the days in the distribution, 1992-1999.. 105
Figure 6-6d. Aerosol light extinction in 26 western Class I areas for the clearest 20 percent of the days in the distribution, 1990-1999.106
Figure 6-6e. Aerosol light extinction in 26 western Class I areas for the middle 20 percent of the days in the distribution, 1990-1999. 106
Figure 6-6f. Aerosol light extinction in 26 western Class I areas for the haziest 20 percent of the days in the distribution, 1990-1999. 106
Figure 6-7a. Class I area significant trends in deciviews for the clearest 20 percent, middle 20 percent, and haziest 20 percent days
as summarized in Table 6-1 108
Figure 6-7b. Class I area significant trends light extinction due to sulfate for the clearest 20 percent, middle 20 percent, and haziest
20 percent days as summarized in Table 6-1 108
Figure 6-7c. Class I area significant trends for light extinction due to organic carbon for the clearest 20 percent, middle 20 percent,
and haziest 20 percent days as summarized in Table 6-1 109
Figure 6-8a. Aerosol light extinction in (Mm-1) for the clearest 20 percent days and contribution by individual particulate matter
constituents, based on 1997-1999 IMPROVE data 110
Figure 6-8b. Aerosol light extinction in (Mm-1) for the middle 20 percent days and contribution by individual particulate matter
constituents, based on 1997-1999 IMPROVE data 110
Figure 6-8c. Aerosol light extinction in (Mm-1) for the haziest 20 percent days and contribution by individual particulate matter
constituents, based on 1997-1999 IMPROVE data Ill
Figure 6-9a. Current visibility impairment expressed in deciviews for the clearest 20 percent days based on 1997-1999
IMPROVE data 112
Figure 6-9b. Current visibility impairment expressed in deciviews for the middle 20 percent days based on 1997-1999
IMPROVE data 112
Figure 6-9c. Current visibility impairment expressed in deciviews for the haziest 20 percent days based on 1997-1999
IMPROVE data 113
Figure 7-1. The National Atmospheric Deposition Program/National Trends Network 116
Figure 7-2. Annual mean sulfate deposition from precipitation, 1990-1992 vs. 1997-1999 117
Figure 7-3. Annual mean ammonium deposition from precipitation, 1990-1992 vs. 1997-1999 118
Figure 7-4. Annual mean nitrate deposition from precipitation, 1990-1992 vs. 1997-1999 119
Figure 7-5. Rural annual mean SO2 concentrations from CASTNet, 1990-1992 vs. 1997-1999 120
Figure 7-6. Rural annual average sulfate concentrations from CASTNet, 1990-1992 vs. 1997-1999 121
Figure 7-7. CASTNet and subset of 34 long-term monitoring sites used for 1990-1999 trends analysis 121
Figure 7-8. Trend in ambient sulfates in the rural eastern United States, based on CASTNet monitoring data, 1990-1999 122
Figure 7-9. Trend in ambient sulfur dioxide in the rural eastern United States, based on CASTNet monitoring data, 1990-1999 122
Figure 7-10. Rural annual mean ammonium concentrations from CASTNet, 1990-1992 vs. 1997-1999 123
Figure 7-11. Rural annual mean total nitrate concentrations from CASTNet, 1990-1992 vs. 1997-1999 123
Figure 7-12. Trend in annual mean ambient sulfur dioxide and sulfate concentrations, based on CASTNet monitoring data, and
regional SO2 emissions from electric utilities in rural eastern United States, 1990-1999 124
IX
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Figures 7-13a. and Figure 7-13b. Trend in annual mean 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,
1990-1999 124
Figures 7-13c. and 7-13d. Trend in annual mean 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, 1990-1999 125
Figure 7-14. Wet and dry components of sulfur deposition, 1999 126
Figure 7-15. Wet and dry components of nitrogen deposition, 1999 126
Figure A-l. (Multiple NA areas within a larger NA area) Two SO2 areas inside the Pittsburgh-Beaver Valley ozone NA 226
Figure A-2. (Overlapping NA areas) Searles Valley PMi0 NA partially overlaps the San Joaquin Valley ozone NA 226
Figure B-l. Carbon monoxide monitoring network, 1999 230
Figure B-2. Lead monitoring network, 1999 230
Figure B-3. Nitrogen dioxide monitoring network, 1999 231
Figure B-4. Ozone monitoring network, 1999 231
Figure B-5. PMW monitoring network, 1999 232
Figure B-6. Sulfur dioxide monitoring network, 1999 232
Figure B-7. Class I Areas in the Improve Network meeting data completeness criteria 234
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Tables
Table 2-1. NAAQS in effect as of December 1999 9
Table 2-2. Milestones in Motor Vehicle Emissions Control 14
Table 2-3. Summary of 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 37
Table 2-5. Percent Contribution to PM25 by Component, 1999 52
Table 2-6. Total SO2 Emissions from Phase I and Non-Phase I Acid Rain Sources: 1990-1999 (million tons) 64
Table 3-1. Summary of MSA Trend Analyses by Pollutant, 1990-1999 70
Table 3-2. AQI Categories, Colors, and Ranges 72
Table 4-1. Areas Redesignated Between September 1999 and September 2000 77
Table 5-1. List of 33 Urban Air Toxics Strategy HAPs 81
Table 5-2. National Summary of Ambient HAP Concentration Trends in Metropolitan Areas, 1994—1999 87
Table 5-3. National Summary of Ambient HAP Concentration Trends in Rural Areas, 1994—1999 95
Table 6-1. Summary of Class I Area Trendl Analysis 107
Table A-la. National Air Quality Trends Statistics for Criteria Pollutants, 1980-1989 128
Table A-lb. National Air Quality Trends Statistics for Criteria Pollutants, 1990-1999 130
Table A-2. National Carbon Monoxide Emissions Estimates, 1970, 1975,1980, 1985, 1989-1999 (thousand short tons) 132
Table A-3. National Lead Emissions Estimates, 1970,1975, 1980,1985, 1989-1999 (short tons) 136
Table A-4. National Nitrogen Oxides Emissions Estimates, 1970, 1975,1980, 1985, 1989-1999 (thousand short tons) 138
Table A-5. National Volatile Organic Compounds Emissions Estimates, 1970,1975, 1980, 1985,1989-1999 (thousand short tons) 142
Table A-6. National PM10 Emissions Estimates, 1970, 1975,1980, 1985, 1989-1999 (thousand short tons) 148
Table A-7. Miscellaneous and Natural PM10 Emissions Estimates, 1970, 1975,1980, 1985, 1989-1999 (thousand short tons) 152
Table A-8. National Sulfur Dioxide Emissions Estimates, 1970, 1975, 1980,1985, 1989-1999 (thousand short tons) 153
Table A-9. National PM25 Emissions Estimates, 1990-1999 (thousand short tons) 156
Table A-10. National Ammonia Emissions Estimates, 1990-1999 (thousand short tons) 160
Table A-ll. National Long-Term Air Quality Trends, 1980-1999 162
Table A-12a. National Air Quality Trends by Monitoring Location, 1980-1989 163
Table A-12b. National Air Quality Trends by Monitoring Location, 1990-1999 164
Table A-13a. National Air Quality Trends Statistics by EPA Region, 1980-1989 165
Table A-13b. National Air Quality Trends Statistics by EPA Region, 1990-1999 167
Table A-14. Maximum Air Quality Concentrations by County, 1999 169
Table A-15. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1999 188
Table A-16. Metropolitan Statistical Area Air Quality Trends, 1990-1999 194
Table A-17. Number of Days with AQI Values Greater Than 100 at Trend Sites, 1990-1999, and All Sites in 1999 219
Table A-18. (Ozone only) Number of Days with AQI Values Greater Than 100 at Trend Sites, 1990-1999, and All Sites in 1999 221
Table A-19. Condensed Nonattainment Areas List(a) 223
Table A-20. Trend in 8-hr ozone concentrations (ppm) exceedances at National Park and National Monument sites, 1990-1999... 227
Table A-21. Onroad and Nonroad Emissions of 21 Mobile Source Air Toxics, 1996 228
Table B-l. Number of Ambient Monitors Reporting Data to AIRS 229
XI
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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
CAS AC 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/NTN National Atmospheric Deposition
Program/National Trends Network
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
NLEV National Low Emission Vehicle
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
PBTs Persistent and Bioaccumulative Toxics
PCBs Polychlorinated Biphenyls
PM10 Particulate Matter of 10 micrometers
in diameter or less
PM25 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
pg/m3 Micrograms Per Cubic Meter
XII
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