United States Office of Air Quality EPA 454/R-98-016
Environmental Protection Planning and Standards December 1998
Agency Research Triangle Park NC 27711
&EPA National Air Quality and
Emissions Trends Report, 1997
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454/R-98-016
National Air Quality and
Emissions Trends Report,
1997
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
December 1998
Printed on recycled paper.
I
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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 recommen-
dation for use.
Acknowledgments
The Trends Team would like to acknowledge the parties who peer
reviewed this report prior to publication and the Trends Workgroup
which includes the following members: Dr. Jane Caldwell, William
Cox, Eric Crump, Laurel Driver, Shelly Eberly, Chebryll Edwards,
Neil Frank, Nash Gerald, Yvonne Johnson, David Lutz, Melissa
McCullough, Dr. David McKee, Brenda Millar, Dr. Deirdre
Murphy, Annie Nikbakht, Sharon Nizich, Ted Palma, Anne Pope,
Holly Reid, Joann Rice, Dr. Mary Ross, Vicki Sandiford, Dr. Roy
Smith, Butch Stackhouse, Greg Stella, Susan Stone, and Chris
Stoneman. Other persons who contributed to the report include
John Bachmann, Rich Cook, and Emily Lada.
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Preface
This is the twenty-fifth 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 inter-
ested parties and individuals.
The report, complete with graphics and data tables, can be accessed via
the Internet at http://www.epa.gov/oar/aqtrnd97/. AQTAG solic-
its 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
For additional air quality data, readers can access the Aerometric
Information Retrieval System's (AIRS) executive software at http://
www.epa.gov/ oar/ airs/aewin.
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IV
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Contents
CHAPTER 1
Executive Summary 1
References and Notes 4
CHAPTER 2
Criteria Pollutants - National Trends 7
Carbon Monoxide 10
Lead 15
Nitrogen Dioxide 20
Ozone 25
Particulate Matter 37
Sulfur Dioxide 47
References and Notes 52
CHAPTER 3
Criteria Pollutants - Metropolitan AreaTrends 55
Status: 1997 55
Trends Analysis 56
The Pollutant Standards Index 60
Summary of PSI Analysis 63
References and Notes 64
CHAPTER 4
Criteria Pollutants - Nonattainment Areas 65
References 67
CHAPTER 5
Air Toxics 69
Background 69
Air Toxics Control Program 70
Air Toxics Characterization 74
Emissions Data 76
Air Toxics Regulation and Implementation Status 79
Special Studies/Programs 81
References 82
V
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CHAPTER 6
Visibility 87
Nature and Sources of the Problem 87
Long-Term Trends 90
Recent Trends in Rural Areas: 1988-1997 90
Current Conditions 94
Programs to Improve Visibility 99
References 99
CHAPTER 7
Acid Deposition 101
Primary Atmospheric Deposition Monitoring Networks 101
Trends Analysis for Sulfate and Nitrate Concentrations in Wet Deposition 102
References 107
APPENDIX A
Data Tables 109
APPENDIX B
Methodology 179
Air Quality Data Base 179
Air Quality Trend Statistics 183
References 183
VI
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Figures
Figure 2-1. Trend in second maximum non-overlapping 8-hour average CO concentrations, 1988-1997 10
Figure 2-2. Diurnal plot of mean winter (December - February) hourly CO concentrations, 1987-1996 11
Figure 2-3. Trend in second maximum non-overlapping 8-hour average CO concentrations by type of location,
1988-1997 11
Figure 2-4. Trend in national total CO emissions, 1988-1997 12
Figure 2-5. CO emissions by source category, 1997 12
Figure 2-6. Long-term trend in second maximum non-overlapping 8-hour average CO concentrations, 1978-1997. .. 13
Figure 2-7. Trend in CO second maximum 8-hour concentration by EPA Region, 1988-1997 14
Figure 2-8. Highest second maximum non-overlapping 8-hour average CO concentration by county,1997 14
Figure 2-9. Trend in maximum quarterly average Pb concentrations (excluding source-oriented sites),1988-1997 16
Figure 2-10. Pb maximum quarterly mean concentration trends by location (excluding source-oriented sites),
1988-1997 16
Figure 2-11. National total Pb emissions trend, 1988-1997 17
Figure 2-12. Pb emissions by source category, 1997 17
Figure 2-13. Long-term ambient Pb trend, 1977-1997 18
Figure 2-14. Trend in Pb maximum quarterly mean concentration by EPA Region, 1988-1997 18
Figure 2-15. Pb maximum quarterly concentration in the vicinity of Pb point sources,1997 19
Figure 2-16. Highest Pb maximum quarterly mean by county, 1997 19
Figure 2-17. Trend in annual N02 mean concentrations, 1988-1997 21
Figure 2-18. Trend in annual mean N02 concentrations by type of location, 1988-1997 21
Figure 2-19. Trend in national total NOx emissions, 1988-1997 22
Figure 2-20. NOx emissions by source category, 1997 22
Figure 2-21. Long-term trend in annual mean N02 concentrations, 1978-1997 23
Figure 2-22. Trend in N02 maximum quarterly mean concentration by EPA Region, 1988-1997 24
Figure 2-23 Highest N02 annual mean concentration by county, 1997 24
Figure 2-24. Trend in annual second-highest daily maximum 1-hour 03 concentrations, 1988-1997 26
Figure 2-25. Trend in annual fourth-highest daily maximum 8-hour 03 concentrations, 1988-1997 27
Figure 2-26. Comparison of actual and meteorologically adjusted trends in 1-hour and 8-hour 99th percentile Q
concentrations, 1988-1997 27
Figure 2-27. Trend in annual second-highest daily maximum 1-hour 03 concentrations by location, 1988-1997 28
Figure 2-28. Trend in annual fourth-highest daily maximum 8-hour 03 concentrations in National Parks, 1988-1997. 28
Figure 2-29. Metropolitan areas subject to the PAMS program 29
Figure 2-30. National total VOC emissions trend, 1988-1997 30
Figure 2-31. VOC emissions by source category, 1997 31
Figure 2-32. Trend in annual second-highest daily maximum 1-hour 03 concentrations, 1978-1997 32
Figure 2-33. Trend in 03 second maximum 1-hour concentrations by EPA Region, 1988-1997 33
Figure 2-34. Trend in 03 fourth maximum 8-hour concentrations by EPA Region, 1988-1997 33
Figure 2-35. Summer 1997 statewide temperature ranks (Source: NOAA, 1997) 35
Figure 2-36. Highest second daily maximum 1-hour 03 concentration by county, 1997 36
Figure 2-37. Trend in annual mean PM10 concentrations, 1988-1997 38
Figure 2-38. PM10 annual mean concentration trends by location, 1988-1997 38
Figure 2-39. National PM10 emissions trend, 1988-1997 (traditionally inventoried primary PM sources only) 39
Figure 2-40. PM10 emissions from traditionally inventoried source categories, 1997 40
VII
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Figure 2-41. Total PM10emissions by source category, 1997 40
Figure2-42. TrendinPM10 annual mean concentrations by EPA Region, 1988-1997 41
Figure2-43. Highest second maximum 24-hour PM10 concentration by county, 1997 41
Figure 2-44. PM10 trend in the average 99th percentile concentration, 1988-1997 43
Figure 2-45. Summary of informationfrom actual measurements of ambient I'M. 44
Figure 2-46. PM25 emission sources 45
Figure2-47. Trend in annual mean S02 concentrations, 1988-1997 47
Figure 2-48. Annual mean S02 concentration by trend location, 1988-1997 48
Figure 2-49. National total S02 emissions trend, 1988-1997 48
Figure 2-50. S02 emissions by source category, 1997 49
Figure 2-51. Long-term ambient S02 trend, 1978-1997 49
Figure 2-52. Trend inS02 annual arithmetic mean concentrations by EPA Region, 1988-1997 50
Figure 2-53. Plants affected by Phase I of the Acid Rain Program 51
Figure 2-54. Highest second maximum 24-hour S02 concentration by county, 1997 51
Figure 3-1. CO Trends in Metropolitan Statistical Areas, 1988-1997 57
Figure 3-2. Pb Trends in Metropolitan Statistical Areas, 1988-1997 57
Figure 3-3. N02 Trends in Metropolitan Statistical Areas, 1988-1997 58
Figure 3-4. Ozone Trends in Metropolitan Statistical Areas, 1988-1997 58
Figure 3-5. Ozone Trends in Metropolitan Statistical Areas (Second Daily Max 1-hour), 1988-1997 59
Figure 3-6. PM10Trends in Metropolitan Statistical Areas (Weighted Annual Mean), 1988-1997 59
Figure 3-7. PM10 Trends in Metropolitan Statistical Areas (99th Percentile), 1988-1997 60
Figure 3-8. S02 Trends in Metropolitan Statistical Areas (Arithmetic Mean), 1988-1997 61
Figure 3-9. S02 Trends in Metropolitan Statistical Areas (Second Max 24-Hour), 1988-1997 61
Figure 3-10. Number of days with PSI values >100, as a percentage of 1988 value 63
Figure 4-1. Location of nonattainment areas for criteria pollutants, September 1998 65
Figure 4-2. Classified ozone nonattainment areas where 1-hour standard still applies, September 1998 66
Figure 5-1. National total HAP emissions by source type, based on 1993 NTI 71
Figure 5-2. Source category contributions for selected states, based on 1993 NTI 71
Figure 5-3. HAP emissions by state, based on 1993 NTI 72
Figure 5-4. State Data Summary for 1996 NTI 72
Figure 5-5. National emissions of 30 draft urban area source HAPs, 1990 75
Figure 5-6. National urban and rural emissions of 30 draft urban area source HAPs, 1990 76
Figure 6-1. Images of Glacier National Park and Dolly Sodds WA 88
Figure 6-2. Shenandoah National Park on clear and hazy days, and the effect of adding 10 \ig/m3 fine particles to
each 89
Figure 6-3. Class I Areas in the IMPROVE Network with at least 6 years of data 90
Figure 6-4. Long-term trend for 75th percentile light coefficient from airport visual data (July - September) 91
Figure 6-5a. Total light extinction trends for eastern Class I areas for haziest, middle, and clearest 20 percent of
distribution, 1988-1997 92
Figure 6-5b. Total light extinction trends for western Class I areas for haziest, middle, and clearest 20 percent of
distribution, 1988-1997 92
Figure 6-6a. Aerosol light extinction in eastern Class I areas for the clearest 20 percent of the distribution, 1988-1997 93
Figure 6-6b. Aerosol light extinction in eastern Class I areas for the middle 20 percent of the distribution, 1988-1997 93
Figure 6-6c. Aerosol light extinction in eastern Class I areas for the haziest 20 percent of the distribution, 1988-1997 93
VIII
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Figure 6-6d. Aerosol light extinction in western Class I areas for the clearest 20 percent of the distribution, 1988-1997 94
Figure 6-6e. Aerosol light extinction in western Class I areas for the middle 20 percent of the distribution, 1988-1997 94
Figure 6-6f. Aerosol light extinction in western Class I areas for the haziest 20 percent of the distribution, 1988-1997 94
Figure 6-7a. Aerosol light extinction (in Mm"1) for the clearest 20 percent days and contribution by individual particulate matter
constituents, based on 1995-1997IMPROVE data 96
Figure 6-7b. Aerosol light extinction (in Mm"1) for the middle 20 percent days and contribution by individual particu-
late matter constituents, based on 1995-1997 IMPROVE data 96
Figure 6-7c. Aerosol light extinction (in Mm"1) for the haziest 20 percent days and contribution by individual particu-
late matter constituents, based on 1995-1997 IMPROVE data 97
Figure 6-8a. Current visibility impairment expressed in deciviews for the clearest 20 percent days based on 1995-1997
IMPROVE data 97
Figure 6-8b. Current visibility impairment expressed in deciviews for the middle 20 percent days based on 1995-1997
IMPROVE data 98
Figure 6-8c. Current visibility impairment expressed in deciviews for the haziest 20 percent days based on 1995-1997
IMPROVE data 98
Figure 7-1. The NADP/NTN Network 102
Figure 7-2. Percent differences in mean annual measured sulfate concentrations as compared to projected concentra-
tions for 1995-1996 for the Eastern United States (from NADP/NTN) 103
Figure 7-3. Sulfate concentration in precipitation, 1997 104
Figure 7-4. Nitrate concentration in precipitation, 1997 104
Figure 7-5. Wet deposition of sulfate, 1997 105
Figure 7-6. Wet deposition of nitrate, 1997 105
Figure 7-7. The CASTNet Network 106
Figure 7-8. Trends in annual mean aerosol sulfate concentrations at Whiteface Mountain and Mayville, 1978-1996. 107
FigureA-1. Two S02 areas inside the Pittsburgh-Beaver Valley ozoneNA. Counted as one NA area 178
Figure A-2. Searles Valley PM10 NA partially overlaps the San Joaquin Valley ozone NA.
Counted as two NA areas 178
Figure B-l. Carbon monoxide monitoring network, 1997 180
Figure B-2. Lead monitoring network, 1997 180
Figure B-3. Nitrogen dioxide monitoring network, 1997 181
Figure B-4. Ozone monitoring network, 1997 181
Figure B-5. PM10 monitoring network, 1997 182
Figure B-6. Sulfur dioxide monitoring network, 1997 182
IX
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Tables
Table 1-1. Percent Decrease in National Air Quality Concentrations and Emissions, 1988-1997 1
Table 2-1. NAAQS in Effect in 1997 7
Table 2-2. Milestones inAuto Emissions Control 12
Table2-3 Summary ofChangesin03,NO!iandTNMOCatPAMSsites,1996-1997 30
Table 2-4. BiogenicsourcesofVOCemissionsbyregion 31
Table 2-5. Total S02 Emissions from Phase I units and Non-Phase I units, 1994-1997 (thousand short tons) 49
Table 3-1. Summary of MSA 10-year Trend Analyses, by Pollutant 56
Table 3-2. Pollutant Standards Index Values with Pollutant Concentration, Health Descriptors, and PSI Colors 62
Table 4-1. Areas Redesignated Between September 1997 and September 1998 66
Table 4-2. Ozone Revocations of Nonattainment Areas Only 66
Table 4-3. Nonattainment Status 67
Table 5-1. Emission Reductions from Full Implementation of MACT Standards 73
Table 5-2. Comparison of 1993 to 1996 Emission Reductions for Mobile On-Road Gasoline Vehicles 74
Table 5-3. HAPs Emitted From On-Road Gasoline Vehicles 74
Table 5-4. 33 Draft Urban HAPs 75
Table 5-5. Summary of Changes in Mean Concentration for HAPs Measured as a Part of the PAMS Program (24-hour
measurements), 1994-1996 77
Table 5-6. Comparison of Loading Estimates for the Great Lakes 77
Table 6-1. Summary of Class I Trend Analysis 95
Table 6-2. Class I areas with potentially deteriorating visibility (based on trend in deciviews) 95
Table A-l. National Air Quality Trends Statistics for Criteria Pollutants, 1988-1997 110
Table A-2. National Carbon Monoxide Emissions Estimates, 1988-1997 (thousand short tons) 112
Table A-3. National Lead Emissions Estimates, 1988-1997 (short tons) 113
Table A-4. National Nitrogen Oxides Emissions Estimates, 1988-1997 (thousand short tons) 114
Table A-5. National Volatile Organic Compounds Emissions Estimates, 1988-1997 (thousand short tons) 115
Table A-6. National Particulate Matter Emissions Estimates, 1988-1997 (thousand short tons) 116
Table A-7. Miscellaneous and Natural Particulate Matter Emissions Estimates, 1988-1997 (thousand short tons) .. 116
Table A-8. National Sulfur Dioxide Emissions Estimates, 1988-1997 (thousand short tons) 117
Table A-9. National Long-Term Air Quality Trends, 1978-1997 118
Table A-10. National Air Quality Trends Statistics by Monitoring Location, 1988-1997 119
Table A-ll. National Air Quality Trends Statistics by EPA Region, 1988-1997 120
Table A-12. Maximum Air Quality Concentrations by County, 1997 122
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997 140
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 147
Table A-15. Number of Days with PSI Values Greater Than 100 at Trend Sites, 1988-1997,
and All Sites in 1997 171
Table A-16. (Ozone only) Number of Days with PSI Values Greater Than 100 at Trend Sites, 1988-1997,
and All Sites in 1997 173
Table A-17. Condensed Nonattainment Area List(s) 175
Table B-l. Number of Ambient Monitors Reporting Data to AIRS 179
X
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Acronyms
AIRS
Aerometric Information Retrieval
System
NET
National Emissions Trends Inventory
NMOC
Non-Methane Organic Compound
Nitrogen Dioxide
AIRMoN
Atmospheric Integrated Assessment
Monitoring Network
no2
AQRV
Air-Quality Related Values
NOx
Nitrogen Oxides
BEB
Biogenic Emissions Inventory System
NOAA
National Oceanic and Atmospheric
Administration
CAA
Clean Air Act
NPS
National Park Service
CAAA
Clean Air Act Amendments
California Air Resources Board
NTI
O,
National Toxics Inventory
Ozone
CARB
CASAC
Clean Air Scientific Advisory
Committee
3
The Ozone Transport Assessment
Group
OTAG
CASTNet
Clean Air Status and Trends Network
OTC
Ozone Transport Commission
CEMs
Continuous Emissions Monitors
CEP
Cumulative Exposure Project
PAHs
PAMS
Polyaromatic Hydrocarbons
Photochemical Assessment
CFR
Code of Federal Regulations
Monitoring Stations
CO
Carbon Monoxide
Pb
Lead
CMSA
Consolidated Metropolitan Statistical
Area
PCBs
Polychlorinated Biphenyls
PMln
Particulate Matter of 10 micrometers
DRI
Desert Research Institute
1U
in diameter or less
DST
Daylight Savings Time
pm25
Particulate Matter of 2.5 micrometers
EPA
Environmental Protection Agency
in diameter or less
FRM
Federal Reference Method
POM
Polycyclic Organic Matter
GDP
Gross Domestic Product
ppm
Parts Per Million
HAPs
Hazardous Air Pollutants
PSI
Pollutant Standards Index
IADN
Integrated Atmospheric Deposition
RFG
Reformulated Gasoline
Network
RVP
Reid Vapor Pressure
IMPROVE
Interagency Monitoring of PROtected
Environments
SAMI
Southern Appalachian Mountain
Institute
LMOS
Lake Michigan Ozone Study
SIP
State Implementation Plan
MACT
Maximum Achievable Control
Technology
SLAMS
State and Local Air Monitoring
Stations
MARAMA
Mid-Atlantic Regional Air
SNMOC
Speciated Non-Methane Organic
Compound
Management Association
MDN
Mercury Deposition Network
so2
Sulfur Dioxide
MSA
Metropolitan Statistical Area
SOx
Sulfur Oxides
NAAQS
National Ambient Air Quality
Standards
SOS
Southern Oxidant Study
STP
Standard Temperature and Pressure
NADP
NADP/NTN
National Atmospheric Deposition
Program
National Atmospheric Deposition
TNMOC
TRI
Total Non-Methane Organic
Compound
Pro gram/ National Trends Network
Toxic Release Inventory
NAMS
National Air Monitoring Stations
TSP
Total Suspended Particulate
NAPAP
National Acid Precipitation
UATMP
Urban Air Toxics Monitoring Program
Assessment Program
VMT
Vehicle Miles Traveled
NARSTO
North American Research Strategy
for Tropospheric Ozone
Northeast States for Coordinated Air
Use Management
VOCs
Volatile Organic Compounds
NESCAUM
Mg/ m3
Micrograms Per Cubic Meter
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Foreword
It is my pleasure to provide the Foreword for this special 25th Anniversary Edition of
the National Air Quality and Emissions Trends Report. A great deal has happened
since I was involved with the publication of the first report. Twenty-five years ago,
there were very limited ambient air pollution data. Today, there are thousands of air
monitoring stations nationwide producing data of the highest quality. As a result,
we can generate much better information on the status of air pollution problems and
efforts to solve them. The state and local air pollution control agencies are to be
applauded for the success of their monitoring programs.
On the occasion of this 25th report, I would like to acknowledge the following EPA
staff who were responsible for producing the very first Trends Report - Bill Cox, Tom
Curran, Bob Faoro, Neil Frank, Virginia Henderson, Alan Hoffman, Tom McMullen,
and Willie Tiggs. Today, the report is produced by the new "Trends Team" consisting
of the following members - Terence Fitz-Simons, Neil Frank, Warren Freas, Dave
Guinnup, James Hemby, Vasu Kilaru, David Mintz, Sharon Nizich, Anne Pope, Mark
Schmidt, Rhonda Thompson, and Miki Wayland.
I would like to thank the Trends Team for developing the report and ensuring
coordination among EPA's Air Offices. In addition, I would like to thank the peer
reviewers who year-after-year help strengthen the report's content, the EPA offices (in
particular, the Acid Rain Division and the Office of Mobile Sources) who provide
data and coordinate with the Trends Team on various sections of the report, and the
EPA staff who contribute to and maintain the Aerometric Information Retrieval
System - EPA's largest source of ambient air quality data.
I would also like to acknowledge the feedback we have received over the years from
our constituents which include many concerned citizens, the Congress, transporta-
tion and fuel industries, colleges and universities, foreign governments, and state
and local air agencies. So that we can continue to provide a report relevant to the
needs of our broad audience, I encourage you to continue communicating your
reactions to us.
We have come a long way in the past 25 years. I hope you enjoy reading this report
and learn more about air pollution issues - our successes, the problems still out there,
and what more needs to be done. We have made tremendous strides towards cleaner
air, but we still have a ways to go.
William F. Hunt
Director
Emissions, Monitoring,
and Analysis Division
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Letter from the Administrator
The Environmental Protection Agency's (EPA) twenty-fifth report on the status and
trends in our nation's air quality shows the progress we have made towards protect-
ing public health and achieving clean air in the United States. EPA has worked in
partnership with industries, state, local, and tribal governments, as well as con-
cerned citizens on a wide variety of air quality issues. These partnerships have been
invaluable in meeting air quality goals and protecting the nation's citizens. This
annual Trends Report documents recent air quality improvements.
For example, emissions of the six principal pollutants (carbon monoxide, lead,
nitrogen dioxide, ozone, particulate matter, and sulfur dioxide) discussed in the
Trends Report have decreased 31 percent since 1970. The Midwest, Northeast, and
Mid-Atlantic regions, which have historically been affected by acid rain, have
experienced reductions in rainfall acidity. We also have seen reductions in hazard-
ous air pollutant emissions from cars and trucks.
The Trends Report shows there are still areas in the country where air pollution
problems threaten public health and the environment. Many cities have levels of air
pollution that exceed national health standards. Some of our most pristine areas,
like national parks, are threatened with high levels of pollution that are harmful to
breathe and reduce our ability to see great distances.
In 1997, EPA approved more protective health standards for the two most pervasive
air pollutants, ozone (smog) and particulate matter (soot). At the same time, EPA
proposed a new regional haze program to address visibility impairment in national
parks and wilderness areas. In September 1998, EPA issued a rule that will signifi-
cantly reduce the regional transport of ozone in 22 eastern states and help states
meet the new national air quality standard for ozone. The Acid Rain Program's
successful market-based trading approach assists industry in reducing emissions
that contribute to acid rain. This trading program serves as a guide for future trading
programs that will play an important role in implementing EPA's new ozone health
standard and in cleaning the air we breathe.
In marking the 25th anniversary of EPA's National Air Quality and Emissions
Trends Report, we acknowledge important improvements in our nation's air quality
as we work to ensure public health and environmental protection for this generation
as well as generations to come.
Carol M. Browner
XIII
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XIV
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CHAPTER
ExecutiveSummary
http://www.epa.gov/oar/aqtrnd97/chapter1.pdf
This is the twenty-fifth annual report
documenting air pollution trends in
the United States.1-24 The scope of this
report includes the criteria pollutants
for which the United States Environ-
mental Protection Agency (EPA) has
established National Ambient Air
Quality Standards (NAAQS), hazard-
ous air pollutants, known as air
toxics, visibility impairment, and acid
rain.
The six criteria pollutants -
carbon monoxide (CO), lead (Pb),
nitrogen dioxide (N02), ozone (03),
particulate matter (PM), and sulfur
dioxide (S02) - are the focus of chap-
ters 2 through 4. Chapters 2 and 3
present national, regional, and metro-
politan area trends, while Chapter 4
summarizes how areas around the
nation are doing with respect to
meeting the NAAQS.
Air toxics, another set of pollut-
ants regulated under the Clean Air
Act (CAA), are discussed in Chapter
5. Both ambient toxics and the depo-
sition of toxics are addressed in this
chapter. Visibility impairment due to
regional haze is discussed in Chapter
6, and acid deposition resulting from
SO2 and NOx emissions is the topic of
Chapter 7.
Discussions throughout this
report are based on the recognition
that many of the programs designed
to reduce ambient concentrations of
the criteria pollutants also aid in
reducing pollution that contributes to
air toxics pollution, visibility impair-
ment, and acid rain. Likewise, re-
quirements under the various air
toxics, visibility, and acid rain pro-
grams can also help reduce emissions
that contribute to ambient concentra-
tions of the criteria pollutants.
Chapter 2
Criteria Pollutants -
National Trends
National and regional air quality
trends for the criteria pollutants are
examined in Chapter 2, along with
supporting emissions data. The air
quality concentrations presented are
based on actual measurements of
pollutant concentrations in the air at
selected monitoring sites across the
country (see Appendix B for details
on the monitoring networks). Emis-
sions estimates presented are calcu-
lated from the total tonnage of these
pollutants, or their precursors, re-
leased into the air annually.25
Table 1-1 summarizes the
10-year percent changes in national
air quality concentrations and emis-
sions between 1988 and 1997. Air
quality has continued to improve
during the past 10 years for all six
pollutants. Nationally, the 1997 aver-
age air quality levels are the best on
record for all six criteria pollutants,
posting concentrations at or below
last year's levels. Furthermore, all the
years in the 1990s have had better
average air quality levels than any of
the years in the 1980s, showing a
steady trend of improvement for each
pollutant.
Emissions of all criteria pollut-
ants have decreased as well, with the
exception of NOx. In September 1998,
EPA issued a rule that will signifi-
cantly reduce regional emissions of
NOx and, in turn, reduce the regional
transport of ozone. This Regional
Transport Rule is discussed in greater
detail in the ozone section of Chapter
2.
Table 1-1. Percent Decrease in National
Air Quality Concentrations and
Emissions, 1988-1997.
Air Quality
Concentration
Emissions
% Decrease
% Decrease
CO
38
25
Pb
67
44
no2
14
1 (NOx)
o3
19(1 -hr)
20 (VOC)
16(8-hr)
PM-io
26
12*
so2
39
12
Includes only directly emitted particles. Secondary PM
formed from S0X, N0X, and other gases comprise a signifi-
cant fraction of ambient PM.
CHAPTER 1: EXECUTIVE SUMMARY
1
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Trends relating to the revised
ozone and PM NAAQS based on data
currently available are also presented.
In July 1997, EPA revised the ozone and
particulate matter standards following
a thorough scientific review process.
Prior to this time, the PM standard
applied to particles whose aerody-
namic size is less than or equal to 10
micrometers, or PMjo The NAAQS
revision strengthened protection
against particles in the smaller part of
that range by adding an indicator for
PM25 (those whose aerodynamic size is
less than or equal to 2.5 micrometers).
The combination of the PM10 and PM2 5
indicators provide protection against a
wide range of particles in both size
and composition. The revised ozone
standard is now based on an 8-hour
averaging time as opposed to 1-hour
under the pre-existing standard. Since
the pre-existing ozone and PM NAAQS
still apply in some areas (see Chapter 2
for details), trends relating to the pre-
existing NAAQS are also discussed in
Chapter 2.
Chapter 3
Criteria Pollutants -
Metropolitan Area
Trends
Chapter 3 characterizes air quality on
a more local level, using three differ-
ent indicators. First, this chapter lists
peak air quality concentrations for
1997 for each Metropolitan Statistical
Area (MSA). Second, 10-year trends
are assessed for each MSA using a
statistical method to measure
whether the trend is up or down. The
results show that 15 MSAs had a
statistically significant upward trend
in ambient concentrations for at least
one criteria pollutant, while 221
MSAs had a statistically significant
downward trend for at least one crite-
ria pollutant. Maps are used to show
how these trends vary spatially. The
third way in which local air quality is
evaluated is by looking at the Pollut-
ant Standards Index (PSI) in the
nation's largest MSAs. The PSI analy-
sis shows that between 1988 and 1997
the total number of "unhealthy" days
decreased an average of 56 percent in
southern California (which, for the
purposes of this analysis, includes the
Los Angeles, Riverside, Bakersfield,
and San Diego MSAs) and an average
of 66 percent in the remaining major
cities across the United States.
Chapter 4
Criteria Pollutants -
nonattainment Areas
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 pollutants. Under the Clean
Air Act Amendments (CAAA) of
1990, there were 274 areas designated
nonattainment for at least one ambi-
ent air quality standard. As of Sep-
tember 1998,130 areas are still
designated nonattainment. The cur-
rent nonattainment area list is based
on the pre-existing ozone and PM
standards. In future years the
nonattainment area list will reflect
areas not meeting the revised ozone
and particulate matter standards.
The current nonattainment areas for
each criteria pollutant are displayed
on one map in this chapter, while a
second map depicts the current ozone
nonattainment areas alone,
color-coded to indicate the severity of
the ozone problem in each area. The
condensed list of nonattainment areas
as of September 1998 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.
Chapter 5
Air Toxics
Chapter 5 presents information on
another set of air pollutants regulated
under the CAA. Hazardous Air Pol-
lutants (HAPs), commonly called air
toxics, are pollutants known to cause
or suspected of causing cancer or
other serious human health effects or
ecosystem damage. There are now
188 such pollutants. The National
Toxics Inventory (NTI) estimates that
8.1 million tons of air toxics are re-
leased to the air annually from sta-
tionary, area, and mobile sources.
This emissions inventory is now be-
ing substantially upgraded with in-
put and review by the states.
While there is currently no
national monitoring network de-
signed to measure air toxics, EPA has
several efforts underway which pro-
vide some information useful to as-
sessing the toxics issue. For instance,
the Agency's Photochemical Assess-
ment Monitoring Stations (PAMS)
program, which is designed to moni-
tor ozone precursors in several major
U.S. cities, provides ambient concen-
tration data for 10 HAPs which are
also ozone precursors. In addition to
the PAMS program, EPA continues to
administer and support voluntary
programs through which states may
collect ambient air quality measure-
ments for a number of air toxics.
Concurrent with these monitoring
efforts, EPA has recently initiated a
program to identify, compile, and
catalogue all previously collected
monitoring data for air toxics.
In addition to the emissions
inventory and limited air quality
2
CHAPTER 1: EXECUTIVE SUMMARY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
monitoring information, EPA has devel-
oped a model to estimate air toxics
concentrations nationwide based on
emissions inventory and meteorologi-
cal information. EPA has used this
model to estimate air toxics concentra-
tions for 1990, based on preliminary
information on emissions and back-
ground concentrations as part of the
Cumulative Exposure Project (CEP).
EPA plans to upgrade and use this
model periodically in future years to
help track estimated air toxics concen-
trations and progress in efforts to ad-
dress potential public health and
environmental concerns associated
with air toxics.
Because of their complex nature
and sheer number, air toxics are regu-
lated differently than the criteria
pollutants. The approach is two-
phased. The first phase consists of
identifying the sources of toxic pol-
lutants and developing technology-
based standards to significantly reduce
their emissions. This phase includes
the MACT (Maximum Achievable
Control Technology) program, as well
as regulations under the specific pol-
lutants and urban area source pro-
grams. Already, the MACT program
has reduced HAP emissions across
many of the source categories by more
than half of the pre-MACT levels (see
Table 5-1 for more details).
The second phase consists of
strategies and programs for evaluat-
ing the remaining risks and ensuring
that the overall program has achieved
substantial reduction in risks to pub-
lic health and the environment. This
phase will involve additional reduc-
tions and incorporate information
developed on remaining risks due to
cumulative exposure to emissions
from mobile as well as stationary
sources. This work will be imple-
mented primarily through the inte-
grated urban air toxics strategy and
residual risk programs, as well as
utilizing information from special
studies on atmospheric deposition,
mercury, and utilities.
Chapter6
Visibility Trends
The CAA authorizes EPA to protect
visibility, or visual air quality,
through a number of programs. In
1987, the Interagency Monitoring of
PROtected Environments (IM-
PROVE) visibility monitoring net-
work was established as a cooperative
effort between EPA, National Park Ser-
vice, U.S. Forest Service, Bureau of
Land Management, U.S. Fish & Wildlife
Service, and state governments. The
objectives of the network are to estab-
lish current conditions, to track
progress toward the national visibility
goal by documenting long-term trends,
and to provide information for deter-
mining the types of pollutants and
sources primarily responsible for vis-
ibility impairment.
The trends analyses presented in
this chapter are based on data from the
IMPROVE network. There were 37
sites having data adequate for assess-
ing trends between 1988 and 1997.
Because of the significant regional
variations in visibility conditions, the
trends are grouped into eastern and
western regions, rather than a national
aggregate. The trends are presented in
terms of the annual average values for
the clearest ("best"), middle, and hazi-
est ("worst") 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
impaired than the best days in the east.
The 10-year trends show that visibility
in the west has improved slightly for
all three ranges (best, middle, and
worst days), while visibility in the east
does not seem to be improving for any
of the ranges.
In July 1997, EPA proposed a
new regional haze program to ad-
dress visibility impairment in na-
tional parks and wilderness areas
caused by numerous sources located
over broad regions. The proposed
program takes into consideration
scientific findings and policy recom-
mendations from a number of
sources. Because of the common
precursors and the regional nature of
the ozone, PM, and regional haze
problems, EPA is developing these
implementation programs together to
integrate future planning and control
strategy efforts to the greatest extent
possible. Implementation of the
NAAQS in conjunction with a future
regional haze program is expected to
improve visibility in urban as well as
rural areas across the country.
Other air quality programs are
expected to lead to emissions reduc-
tions that will improve visibility in
certain regions of the country. The
acid rain program will achieve sig-
nificant regional reductions in SOx
emissions, which is expected to re-
duce sulfate haze particularly in the
eastern United States. The recent
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.
Chapter 7
Acid Deposition
New to the report this year, the acid
deposition chapter presents informa-
tion concerning wet acidic deposition
(commonly called acid rain) and dry
CHAPTER 1: EXECUTIVE SUMMARY
3
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
acidic deposition. Wet deposition
occurs when gaseous or particulate
pollutants enter water droplets in the
air, and fall as rain, snow, or other
precipitation. Dry deposition occurs
when particles settle by gravity or
when gaseous pollutants are
adsorbed by surface waters or bound
chemically to soil surfaces.
The National Atmospheric
Deposition Program/National Trends
Network (NADP/NTN) and the
Clean Air Status and Trends Network
(CASTNet), two monitoring networks
described in detail in the chapter,
monitor wet and dry acid deposition,
respectively. NADP/NTN consists of
nearly 200 sites nationwide, while
CASTNet contains 72 sites. These
sites monitor a number of com-
pounds, including sulfates and ni-
trates, which are formed from sulfur
oxides and nitrogen oxides reacting
in the atmosphere.
Wet deposition data from the
NADP/NTN show that sulfate con-
centrations in precipitation have
decreased over the past two decades,
with a particularly sharp decrease
occurring since 1994 in the eastern
United States. This recent reduction
is directly related to large regional
decreases in SO2 emissions resulting
from phase I of the Acid Rain pro-
gram (see the S02 section in Chapter
2 for more details). Nitrate concen-
trations in recent years at the NADP/
NTN sites are not appreciably differ-
ent from historical levels.
Dry deposition data from the
CASTNet sites show that sulfate con-
centrations decreased 26 percent
between 1989 and 1995. During that
same period, total nitrate concentra-
tions decreased 8 percent. Nitrate
concentrations should continue to
decline due in part to the implemen-
tation of the Phase I Acid Rain NOx
Control Program, along with the Re-
gional Transport rule, both of which
are designed to reduce NOx emissions.
(NOxis the generic term for a group of
highly reactive gases, all of which
contain nitrogen and oxygen in varying
amounts. The criteria pollutant NOz is
a common form of NOx and is prevalent
in NOx emissions from the burning of
fuels at high temperatures, as in a
combustion process.)
In addition to the trends informa-
tion in this chapter, maps of the 1997
wet and dry deposition data are also
presented.
The Appendices
Finally, Appendix A provides ex-
panded tables of the air quality con-
centrations and emissions data
described throughout this report.
Appendix B summarizes the method-
ology which is the basis for the trends
analyses in Chapter 2, and also pro-
vides maps of the current monitoring
network for each criteria pollutant.
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 Protection 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
Standards, 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
Standards, 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
Standards, 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. Environmental
Protection Agency, Office of Air Quality
Planning and Standards, Research
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
CHAPTER 1: EXECUTIVE SUMMARY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
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.
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. Emissions estimates are derived from
many factors, including the level of
industrial activity, technology changes,
fuel consumption, vehicle miles traveled
(VMT), and other activities that affect air
pollution. In 1994, EPA began incorpo-
rating direct emissions measurements of
sulfur dioxide and nitrogen oxides (NOx)
for the electric utility industry. Additional
emissions information can be found at
http://www.epa.gov/oar/oaqps/efig.
CHAPTER 1: EXECUTIVE SUMMARY
5
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
6 CHAPTER 1: EXECUTIVE SUMMARY
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CHAPTER 2
GilaiaMMrN^^
http://www.epa.gov/oar/aqtrnd97/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 Air Quality
Standards (NAAQS). NAAQS are in
place for the following six criteria
pollutants: carbon monoxide (CO),
lead, nitrogen dioxide, ozone, par-
ticulate matter (PM), and sulfur diox-
ide (S02). Table 2-1 lists the NAAQS
for each pollutant in terms of the
level and averaging time of the stan-
dard used to evaluate compliance.
There are two types of stan-
dards: primary and secondary.
Primary standards protect against
adverse health effects, whereas
secondary standards protect against
welfare effects such as damage to
crops, ecosystems, vegetation,
buildings, and decreased visibility.
There are primary standards for all
of the criteria pollutants, and some
pollutants (PM and S02) have
primary standards for both
long-term (annual average) and
short-term (24 hours or less) averag-
ing times. Short-term standards
most directly protect people from
any adverse health effects associated
with peak short-term exposures to
air pollution, while long-term
standards can protect people from
adverse health effects associated
with short- and long-term exposures
Table 2-1. NAAQS in Effect in 1997
Pollutant
Primary
(Health Related)
Type of Average Standard Level
Concentration3
Secondary
(Welfare Related)
Type of Average Standard Level
Concentration
CO
8-hourb 9 ppm
(10 mg/m3)
1-hourb 35 ppm
(40 mg/m3)
No Secondary Standard
No Secondary Standard
Pb
Maximum 1.5 |jg/m3
Quarterly Average
Same as Primary Standard
no2
Annual 0.053 ppm
Arithmetic Mean (100 |jg/m3)
Same as Primary Standard
03
1-hour° 0.12 ppm
(235 |jg/m3)
8-hourd 0.08 ppm
(157 |jg/m3)
Same as Primary Standard
Same as Primary Standard
PM,,
pm25
Annual 50 |jg/m3
Arithmetic Mean
24-houre 150 |jg/m3
Annual 15|jg/m3
Arithmetic Mean'
24-hour9 65 |jg/m3
Same as Primary Standard
Same as Primary Standard
Same as Primary Standard
Same as Primary Standard
so2
Annual 0.03 ppm
Arithmetic Mean (80 |jg/m3)
24-hourb 0.14 ppm
(365 |jg/m3)
3-hourb
0.50 ppm
(1,300 |jg/m3)
s Parenthetical value is an approximately equivalent concentration.
b Not to be exceeded more than once per year.
c Notto beexceeded more than once per year on average.
d 3-yearaverageofannual4th highest concentration.
e The pre-existing form is exceedance-based. The revised form isthe 99th percentile.
f Spatially averaged over designated monitors.
9 The form is the 98th percentile.
Source: 40CFRPart50.
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 7
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
to air pollution. Secondary stan-
dards have been established for each
criteria pollutant except CO. Sec-
ondary standards are identical to the
primary standard with the exception
of S02.
On July 18,1997, EPA issued
the revised NAAQS for ozone and
PM. The form of the revised ozone
standard is the annual fourth
highest 8-hour concentration
averaged over 3 years. The level of
the revised ozone NAAQS is 0.08
ppm. The form of the revised short-
term PM10 standard is the 99th
percentile 24-hour average concen-
tration averaged over 3 years. The
level of the revised short-term PM10
standard of 150 ug/m3 was retained.
The form and level of the long-term
PM10 standard were retained. In
addition, an indicator for PM2 5 was
introduced to protect against
particulate matter in the smaller end
of the particle range. The form of
the PM2S short-term standard is the
99th percentile 24-hour average
concentration averaged over 3 years,
and the associated level is 65 ug/m3.
The form of the PM2 5 long-term
standard is the annual arithmetic
mean spatially averaged over
designated monitors averaged over
3 years, and the associated level is
15 ug/m3. The revised standards
are listed in Table 2-1 and are
discussed in greater detail within
the ozone and PM sections of this
chapter.
The pre-existing standards for
ozone are still in effect for areas that
did not meet them prior to the
NAAQS revisions. The pre-existing
NAAQS for PM10 are in effect until
states take steps to remove them.
Specifically, states must have a
federally-approved State Implemen-
tation Plan (SIP) that shows how
they can implement the revised PM
NAAQS and all state adopted and
implemented control measures.
Both the pre-existing and the
revised NAAQS are listed in Table 2-
1 and trends associated with both
are examined in this chapter.
Most of the trends information
presented in this chapter is based on
two types of data: ambient concen-
trations and emissions estimates.
Ambient concentrations are mea-
surements of pollutant concentra-
tions in the ambient air from
monitoring sites across the country.
This year's report contains trends
data accumulated from 1988 to 1997
on the criteria pollutants at 2,778
monitoring stations located
throughout the United States. The
trends presented here are derived
from the composite average of these
direct measurements. The averag-
ing times and air quality statistics
used in the trends calculations relate
directly to the NAAQS.
The second type of data
presented in this report reflects
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 period. In
addition, some emissions estimates
are based on measurements from
continuous emissions monitors
(CEMs) that have recently been
installed at major electric utilities to
measure actual emissions. This
report incorporates data from CEMs
collected between 1994 and 1997 for
NOx and S02 emissions at major
electric utilities.
Changes in ambient concentra-
tions do not always track changes in
emissions estimates. There are four
known reasons for this. First,
because most monitors are posi-
tioned 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
generally dominated by mobile
sources, while total emissions in
rural areas may be dominated by
large stationary sources such as
power plants and smelters.
Second, emissions for some
pollutants are calculated or mea-
sured in a different form than the
primary air pollutant. For example,
concentrations of ozone are caused
by VOC emissions as well as NOx
emissions.
Third, the amount of some
pollutants measured at monitoring
locations 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 condi-
tions often control the formation
and buildup of pollutants in the
ambient air. For example, peak
ozone concentrations typically occur
during hot, dry, stagnant summer-
time conditions; CO is predomi-
nately a cold weather problem; and
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 com-
pute the trends estimates in this
chapter, please refer to Appendix B.
8 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
The National Perspective: Past, Present, and Future
Improvements in the face of Economic
Growth
National reductions in air quality concentra-
tions and emissions continue to occur in the
face of economic growth. Since 1970, total
U.S. population increased 31 percent, vehicle
miles traveled increased 127 percent, and the
gross domestic product (GDP) increased 114
percent.12 3 During that same period, notable
reductions in air quality concentrations and
emissions took place. Aggregate criteria
pollutant emissions decreased 31 percent.
When examined individually, emissions for all
criteria pollutants except NOx decreased
between 1970 and 1997, the greatest
improvement being a 98-percent decrease in
lead emissions. Though air quality trends are
not available back to 1970, in most cases they
are available for the past 20 years. Reductions
in air quality concentrations between 1978
and 1997 are impressive with CO, lead, and
S02 decreasing by more than half.4 These air
quality improvements are a direct result of
EPA working with states, industry, and other
partners to effectively establish and imple-
ment clean air laws and regulations.
The Need for Continued
Progress
While progress has been made, it
is important not to lose sight of the
air pollution problems that still
remain. Though air quality trends
are improving nationally, there are
still areas, both urban and rural,
with concentrations above the level
of the national standard and even
areas with worsening trends (in
addition to Chapter 2, see Chapter
3 for more details on urban areas
and Chapter 6 for more details on
rural areas). Based upon
monitoring data submitted to EPA's
Aerometric Information Retrieval
System (AIRS) data base,
approximately 107 million people
in the United States reside in
counties that did not meet the air
quality standard for at least one of
the NAAQS pollutants for the single year 1997.5
Long-term Percent Change in National Air Quality
Concentration and Emissions
Air Quality
Concentration
%Change 1978-1997
Emissions
% Change 1970-1997
CO
-60%
-32%
Pb
-97%
-98%
no2
-25%
+11%
03
-30% (1 hr)
-37%
PM10
Data Not
-75%
Available
S02
-55%
-35%
Includes only directly emitted particles. Secondary PM formed from SOx, Nox, and other
gases comprise a significant fraction of ambient PM.
l
Vehicle Miles Traveled Increased 127%
U.S. Gross Domestic Product Increased 114%
U.S. Population Increased 31%
Aggregate Emissions Decreased 31%
(Six Principal Pollutants)
Total U.S. Population, vehicle miles traveled, U.S. gross domestic product, and aggregate
emissions, 1970-1997.
CO
Pb
no2
°3
PM-10
PM-2.5
so2
Any
NAAQS
9.1
]2.4
O
147.9 (pre-existing NAAQS)
1101.6
7.9 (pre-existing NAAQS)
9.7 (revised NAAQS)
Data not yet available
0.1
(revised NAAQS)
1 52.6 (pre-existing NAAQS)
1107
20
40 60 80
Millions of Persons
(revised NAAQS)
100 120
Number of people living in counties with air quality concentrations above the level of
the NAAQS in 1997.
1. Statistical Abstract of the United States, 1996, U.S. Department of Commerce, U.S. Bureau of Census.
2. E.H. Pechan & Associates, Sprinfield, VA, October 1998.
3. The Bureau of Economic Analysis, Department of Commerce, website at http://www.bea.doc.gov/bea/.
4. Because of evolving monitoring networks, these long-term changes in air quality concentrations are not as certain as the more recent 10-year assessment.
5. The population estimates are based upon only a single year of data, 1997, and only consider counties with monitoring data for each pollutant. They are intended to provide a relative
measure of the extent of the problem for each pollutant in 1997. An individual living in a county that had a measured concentration above the level the NAAQS may not actually be
exposed to unhealthy air.
6. The number of people living in formally designated nonattainment areas as of September 1998 was approximately 113 million. These population estimates differ because formal
nonattainment designations are based on multiple years of data rather than a single year and generally do not follow county boundaries. For a pollutant such as ozone,
nonattainment areas typically compose the entire metropolitan area, which may include additional counties that do not contain monitors. Also, designations have not yet been made
forthe revised ozone and PM NAAQS. Therefore, the nonattainment area population does not reflect the revised NAAQS.
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 9
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Carbon Monoxide Figure 2-1. Trend in second maximum non-overlapping 8-hour average CO
concentrations, 1988-1997.
• Air Quality Concentrations
1988-97
38% decrease
1996-97
7% decrease
• Emissions
1988-97
25% decrease
1996-97
3% decrease
Nature and Sources
Concentration, ppm
-90th Percentile
368 Sites
Mean
Median
10th Percentile
NAAQS
88 89 90 91 92 93 94 95 96 97
CO is a colorless, odorless, and at
much higher levels, a poisonous gas
formed when carbon in fuels is not
burned completely. It is a product of
motor vehicle exhaust, which contrib-
utes about 60 percent of all CO emis-
sions nationwide. High concentra-
tions of CO generally occur in areas
with heavy traffic congestion. In
cities, as much as 95 percent of all CO
emissions may emanate from auto-
mobile exhaust. Other sources of CO
emissions include industrial pro-
cesses, non-transportation fuel com-
bustion, and natural sources such as
wildfires. Woodstoves, cooking, ciga-
rette smoke, and space heating are
sources of CO in indoor environ-
ments. Peak CO concentrations typi-
cally occur during the colder months
of the year when CO automotive
emissions are greater and nighttime
inversion conditions are more fre-
quent.
Health Effects
Carbon monoxide enters the blood-
stream through the lungs and reduces
oxygen delivery to the body's organs
and tissues. The health threat from
lower levels of CO is most serious for
those who suffer from cardiovascular
disease, such as angina pectoris. At
much higher levels of exposure, CO
can be poisonous, and healthy indi-
viduals may also be affected. Visual
impairment, reduced work capacity,
10
5
0
reduced manual dexterity, poor learn-
ing ability, and difficulty in perform-
ing complex tasks are all associated
with exposure to elevated CO levels.
Primary Standards
There are two primary NAAQS for
ambient CO, a 1-hour average of 35
ppm and an 8-hour average of 9 ppm.
These concentrations are not to be
exceeded more than once per year.
There currently are no secondary
standards for CO.
National 10-Year Trends
The use of a moving 10-year trends
window maximizes the number of
sites that meet the minimum data
completeness requirement of 8 years
of ambient monitoring data. The
10-year trend in ambient CO concen-
trations is graphically shown in Fig-
ure 2-1. Air quality improvement is
clear given the decreases shown in
CO concentrations for "peak" sites,
"typical" sites, and "clean" sites (i.e.,
the 90th percentile, the composite
mean, and the 10th percentiles.) Na-
tionally, CO concentrations decreased
38 percent during the past 10 years as
measured by the composite average
of the annual second highest 8-hour
concentration. Between 1996 and
1997, national composite average CO
concentrations decreased 7 percent.
Nationally, the 1997 composite aver-
age 8-hour ambient CO concentration
is the lowest level recorded during
the past 10 years.
Figure 2-2 presents diurnal
patterns in hourly CO concentrations
averaged across all sites for the
10-year period, 1987-96. The figure
shows that reductions in CO concen-
trations are not limited to the peak
hours, but are found at all hours
throughout the day.1
Reductions in ambient CO con-
centrations also occurred across all
10 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
monitoring environments—urban,
suburban, and rural sites. Figure 2-3
shows that urban monitoring sites
record higher CO concentrations on
average, than suburban sites, with
the lowest levels found at 12 rural CO
sites. During the past 10 years, com-
posite mean CO 8-hour concentra-
tions decreased 39 percent at 208
urban sites, 35 percent at 145 subur-
ban locations, and 46 percent at 12
rural monitoring sites.
Emissions Trends
Figure 2-4 shows that national total
CO emissions have decreased 25
percent since 1988. Emissions from
all transportation sources have de-
creased 22 percent during the past 10
years, despite a 25 percent increase in
vehicle miles traveled (VMT). Be-
cause the urban CO monitoring sites
are primarily mobile-source oriented,
the 38 percent reduction in CO con-
centrations more closely tracks the
estimated 29 percent reduction in
emissions from highway vehicles.
Figure 2-6 shows that the transporta-
tion category, composed of on-road
and off-road sources, accounts for 77
percent of the nation's total CO emis-
sions in 1997. Total CO emissions
decreased 2 percent since 1996, with
CO emissions from highway vehicles
recording a 6-percent decline since
last year, while VMT increased by 2
percent since 1996.
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 include
establishing national standards for
tailpipe emissions, new vehicle tech-
nologies, and clean fuels programs.
These measures have led to reduc-
tions in emissions of CO as well as
Figure 2-2. Diurnal plot of mean winter (December-February) hourly CO
concentrations, 1987-1996.
Concentration, ppm
Figure 2-3. Trend in second maximum non-overlapping 8-hour average CO
concentrations by type of location, 1988-1997.
Concentration, ppm
8
7
6
5
4
3
2
1
Rural (12 sites) Suburban (145 sites) Urban (208 sites)
o
88 89 90 91 92 93 94 95 96 97
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 11
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-4. Trend in national total CO emissions, 1988-1997.
Thousand Short Tons Per Year
140,000
120,000
100,000
80,000
60,000
40,000
20,000
0
l~l Fuel Combustion H Industrial Processing
n Transportation l~l Miscellaneous
88 89 90 91 92 93 94 95 96 97
Figure 2-5. CO emissions by source category, 1997.
Transportation 76.6%
Industrial Processes 6.9%
Fuel Combustion 5.5%
Miscellaneous 10.9%
other pollutants. State and local
emissions reduction measures in-
clude inspection and maintenance (I/
M) programs and transportation
management programs.
Table 2-2. Milestones in Auto Emissions
Control
1970 New Clean Air Act sets auto
emissions standards.
1971 Charcoal canisters appear to
meet evaporative standards.
1972 EGR 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 02
sensors appear.
1983 l/M programs are established
in 64 cities.
1989 Fuel volatility limits are set
for RVP
1990 CAAA set new tailpipe stan-
dards.
1992 Oxyfuel introduced in cities
with high CO levels.
1993 Limits set on sulfur content
of diesel fuel.
1994 Phase-in begins of new vehi-
cle standards and technolo-
gies.
In the area of clean fuels, the
1990 Clean Air Act Amendments
(CAAA) require oxygenated gasoline
programs in several regions during
the winter months. Under the pro-
gram regulations, a minimum oxygen
content (2.7 percent by weight) is
required in gasoline to ensure more
complete fuel combustion.2,3 Of the
36 nonattainment areas that initially
implemented the program in 1992, 25
12 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-6. Long-term trend in second maximum non-overlapping 8-hour average CO
concentrations, 1978-1997.
1978-87 1988-97
(208 sites) (368 sites)
78 80 82 84 86 88 90 92 94 96
areas continue to use oxygenated
fuels. An analysis of the oxygenated
fuels program in several cities with
winter oxygenated gasoline programs
showed reductions in ambient CO
concentrations of about 10 percent.4
Other studies estimated that the
oxyfuel effect was an average total
reduction in ambient CO concentra-
tions of 7 to 14 percent overall for the
eight winter seasons from 1986
through 1994.5,6
National 20-Year Trends
Because of the annual loss and re-
placement of ambient monitoring
sites, too few sites are able to meet a
20-year data completeness criteria.
Thus, long-term trends are assessed
by piecing together two separate
10-year trends data bases. Because
the number of monitoring sites na-
tionwide can vary greatly over a
20-year period, two 10-year periods
are used to capture a common set of
sites for each period. Although there
are differences in the mix of trend
sites for the two periods (208 vs. 367
sites), Figure 2-6 shows a consistent
decline in CO concentrations during
the past 20 years. Nationally, the
1997 composite average ambient
concentration is 60 percent lower
than 1978 and the lowest level re-
corded 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,
1988-1997. All 10 EPA Regions re-
corded 10-year declines in CO levels
as measured by the regional compos-
ite mean concentrations. The largest
concentration reductions are in the
Northcentral, Rocky Mountain and
Concentration, ppm
14
12
10
8
6
4
2
0
Northwest states. Smaller reductions
can be seen in the West, South and
Midwest regions. Only the Southeast
(Region 4) saw an upturn between
1996 and 1997 (an increase of 3 per-
cent).
1997 Air Quality Status
The map in Figure 2-8 shows the
variations in CO concentrations
across the country in 1997. The air
quality indicator is the highest annual
second maximum 8-hour concentra-
tion measured in each county. The bar
chart to the left of the map displays
the number of people living in coun-
ties within each concentration range.
The colors on the map and bar chart
correspond to the colors of the con-
centration ranges displayed in the
map legend. Only 6 of the 537 moni-
toring sites reporting ambient CO
data to AIRS failed to meet the CO
NAAQS in 1997. These six sites were
located in three counties with a total
population of 9 million people —Los
Angeles County, CA; Fairbanks, AK;
and Imperial County, CA (Calexico,
CA). The site in this latter area is
located % mile north of the border
crossing with Mexicali, Mexico. This
is an improvement over the 1996
totals of seven counties with a total
population of 13 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 1997 county maxi-
mum second-highest non-overlap-
ping 8-hour CO concentrations are
listed in Table A-ll.
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 13
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-7. Trend in CO second maximum 8-hour concentrations by EPA Region, 1988-97.
f 42%
^46%
¦J 45%
4 43%
J 32%
¦f 40%
#¦ 29%
39%
The National Trend
6.3
^28%
f 29%
# 38%
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.
Figure 2-8. Highest second maximum non-overlapping 8-hour average CO concentration by county, 1997.
180
170
160
150
140
130
120
c
| 110
i
c 100
c
o
§ 90
D
a
O 80
Q.
O
70
60
50
40
30
20
10
Concentration (ppm) <4.5 4.5-9.4 I I 9.5-15.4 15.5-30.4
14 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Lead
• Air Quality Concentrations
1988-97
67% decrease
1996-97
no change
• Emissions
1988-97
44% decrease
1996-97
no change
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
remove lead from gasoline, the con-
tribution from the transportation
sector has dramatically declined.
Today, metals processing is the major
source of lead emissions to the atmo-
sphere. The highest ambient air con-
centrations of lead are found in the
vicinity of ferrous and nonferrous
smelters, battery manufacturers, and
other stationary sources of lead emis-
sions.
Health and Environmental Effects
Exposure to lead occurs mainly
through inhalation and ingestion of
lead in food, water, soil, or dust. It
accumulates in the blood, bones, and
soft tissues. Lead also can adversely
affect the kidneys, liver, nervous
system, and other organs. Excessive
exposure to lead may cause neuro-
logical impairments such as seizures,
mental retardation, and/ or behav-
ioral disorders. Even at low doses
lead exposure is associated with
changes in fundamental enzymatic,
energy transfer, and homeostatic
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 disease. Recent
studies also indicate that neuro-
behavioral changes may result from
lead exposure during the child's first
years of life.
Airborne lead also can have
adverse 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 reason,
the secondary standard for lead is
identical to the primary standard. At
relatively low concentrations (2-10
Hg/ m3), lead can inhibit plant growth
and lead to a shift to more tolerant
plant species near roadsides and
stationary source emissions.
In spite of the fact that the ma-
jority 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), re-
duced numbers of invertebrates,
reduced decomposition and nitrifica-
tion rates, and alterations in other soil
parameters. Because lead remains in
the soil, soil concentrations continue
to build over time even when deposi-
tion 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. How-
ever, 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
continue to be implications for the
long-term impact of lead on ecosys-
tem function and stability. [See also
Chapter 5: Air Toxics and the Decem-
ber 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 (Jig/ m3.
National 10-Year Trends
The statistic used to track ambient
lead air quality is the maximum quar-
terly mean concentration of each
year. A total of 195 ambient lead
monitors met the trends data com-
pleteness criteria. Point source-ori-
ented monitoring data were excluded
from all ambient trends analyses
presented in this section so as not to
mask the underlying urban trends.
Figure 2-9 indicates that between
1988 and 1997, maximum quarterly
average lead concentrations de-
creased 67 percent at population-
oriented monitors. The decline was
fairly similar at rural, suburban, and
urban locations as seen in Figure 2-
10. Between 1996 and 1997, national
average lead concentrations
(approaching the minimum detect-
able level) remained unchanged.
Emissions Trends
Figure 2-11 shows that total lead
emissions decreased 44 percent be-
tween 1988 and 1997. The large am-
bient and emissions reductions are a
waning result of the phase-out of
leaded gasoline. Table A-3, which
lists lead emissions by major source
category, shows that on-road vehicles
accounted for 82 percent of the 10-
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 15
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-9. Trend in maximum quarterly average Pb concentrations (excluding source
oriented sites), 1988-1997.
Concentration, |jg/m3
2.0
1.5-
1.0
0.5
0.0L
n~90th Percentile
s|<-Mean
-Median
—I—10th Percentile
195 Sites
NAAQS
88 89 90 91 92 93 94 95 96 97
Figure 2-10. Pb maximum quarterly mean concentration trends by location (excluding
source-oriented sites), 1988-1997.
Concentration, |jg/m3
0.16
Rural (4 sites) Suburban (99 sites) Urban (90 sites)
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
88 89 90 91 92 93 94 95 96 97
year emissions decline. Between 1996
and 1997, lead emissions did not
change substantially. Figure 2-12
shows that industrial processes were
the major source of lead emissions in
1997, accounting for 74 percent of the
total. The transportation sector (on-
road and non-road sources) now
accounts for only 13 percent of total
1997 lead emissions; on-road vehicles
account for only one-half of a percent.
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 pe-
riod, such as illustrated in Figure
2-13. Between 1978 and 1997, ambi-
ent concentrations of lead declined 97
percent. This large decline tracks well
with the overall emissions trend,
which shows a decline of 98 percent
between 1975 and 1997.
Regional Trends
Figure 2-14 segregates the ambient
trend analysis by EPA region. Al-
though all regions showed large con-
centration reductions between 1988
and 1997, there were some intermittent
upturns. Many of the latter year up-
turns and dips can be attributed to the
inherent variability associated with
data reported near the instrument's
lower limit of detection.
1997 Air Quality Status
The large reductions in long-term
lead emissions from transportation
sources has changed the nature of the
ambient lead problem in the United
States. Because industrial processes
are now responsible for all violations
of the lead standard, the lead moni-
toring strategy now focuses on these
emissions point sources. The map in
16 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-15 shows the lead monitors
oriented in the vicinity of major
sources of lead emissions. In 1997,
four lead point sources had one or
more source-oriented monitors that
violated the NAAQS. These four
sources are ranked in Figure 2-15
according to the site with 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 con-
centration by county in 1997. Four
counties, with a total population of 2.4
million and containing the point
sources identified in Figure 2-15, did
not meet the lead NAAQS in 1997.
Monitoring Status
Because of the shift in ambient air
monitoring focus from mobile source
emissions to stationary point sources
of lead air pollution, EPA has taken
action to revise the lead air monitor-
ing regulations. This action is being
taken at the direct request of numer-
ous State and local agencies whose
on-road mobile source-oriented lead
monitors have been reporting peak
lead air pollution values that are
many times less than the quarterly
lead NAAQS of 1.5 ng/m3 for a num-
ber of consecutive years. EPA pub-
lished a direct final rule for ambient
air quality surveillance for lead on
November 5,1997 in the Federal Reg-
ister. However, due to adverse com-
ments received, the rule was
withdrawn on December 23,1997. It
is anticipated that the final rule will
be published in late December 1998.
The previous (current) regulation
requires that each urbanized area
with a population of 500,000 or more
operate at least two lead National Air
Figure 2-11. National total Pb emissions trend, 1988-1997.
Short Tons Per Year
8,000
6,000
4,000
2,000
II Fuel Combustion | Industrial Processing Q Transportation
88 89 90 91 92 93 94 95 96 97
Figure 2-12. Pb emissions by source category, 1997.
Fuel Combustion 12.6%
Transportation 13.3%
Including on-road
and off-road sources.
Industrial Processes 74.2%
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 17
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-13. Long-term ambient Pb trend, 1977-1997.
Concentration, |jg/m3
2
1.5
0.5
1978-87 1988-97
(160 sites) (195 sites)
Monitoring Stations (NAMS). The
new lead monitoring rule maintains a
minimum number of traditional
types of lead monitoring sites in the
largest metropolitan areas, and it
refocuses available monitoring re-
sources into areas with industrial
sources.
78 80 82 84 86 88 90 92 94 96
Figure 2-14. Trend in Pb maximum quarterly mean concentrations by EPA Region, 1988-1997.
¦f- 44%
#¦ 70%
•f- 67%
.17
~ 65°/o
06
~ 43%
Insufficient
Trend Data
§¦ 73%
.12
The National Trend
.12
67%
57%
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2.
Concentrations are ug/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.
18 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-15. Pb maximum quarterly concentration in the vicinity of Pb point sources, 1997.
Rank
ST
Emission Source
Max Qtr Avg
Mg/m3
1
MO
Doe Run (Herculeneum)
8.53
2
PA
Franklin Smelter
6.98
3
IL
Chemetco
2.11
4
NE
ASARCO (Omaha)
1.95
• Exceeds the NAAQS
• Meets the NAAQS
Note: Site markers may overlap.
Figure 2-16. Highest Pb maximum quarterly mean by county, 1997.
Concentration (ug/m3)
<0.75
0.75-1.54
1.55-3.04
= 6.05
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 19
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Nitrogen Dioxide
• Air Quality Concentrations
1988-97 14% decrease
1996-97 no change
• Emissions
1988-97 1% decrease
1996-97 1% increase
Nature and Sources
Nitrogen dioxide (N02) is a reddish
brown, highly reactive gas that is
formed in the ambient air through the
oxidation of nitric oxide (NO). Nitro-
gen oxides (NOx), the term used to
describe the sum of NO, N02 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. A variety of NOx com-
pounds and their transformation
products occur both naturally and as
a result of human activities. Anthro-
pogenic (i.e., man-made) emissions of
NOx account for a large majority of
all nitrogen inputs to the environ-
ment. The major sources of anthro-
pogenic NOx emissions are
high-temperature combustion pro-
cesses, such as those occurring in
automobiles and power plants. Most
(about 95 percent) of NOx from com-
bustion sources is emitted as NO; the
remainder is largely N02. Because
NO is readily converted to N02 in the
environment, the emissions estimates
reported here assume nitrogen oxides
are in the N02 form. Natural sources
of NOx are lightning, biological and
abiological processes in soil, and
stratospheric intrusion. Ammonia
and other nitrogen compounds pro-
duced naturally are important in the
cycling of nitrogen through the eco-
system. Home heaters and gas stoves
also produce substantial amounts of
N02 in indoor settings.
Health and Environmental Effects
N02 is the only nitrogen oxide suffi-
ciently widespread and commonly
found in ambient air at high enough
concentrations to be a matter of pub-
lic health concern. The health effects
of most concern associated with
short-term exposures (e.g., less than 3
hours) to N02 at or near the ambient
N02 concentrations seen in the
United States include changes in
airway responsiveness and pulmo-
nary function in individuals with pre-
existing respiratory illnesses and
increases in respiratory illnesses in
children (5-12 years old).7,8
Evidence suggests that long-
term exposures to N02 may lead to
increased susceptibility to respiratory
infection and may cause alterations in
the lung. Atmospheric transforma-
tion of NOx can lead to the formation
of ozone and nitrogen-bearing par-
ticles (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
potential changes in the composition
and competition of some species of
vegetation in wetland and terrestrial
systems, and visibility impairment.
However, the role nitrogen deposi-
tion plays in the acidification of fresh-
water bodies and the eutrophication
of estuarine and coastal waters (e.g.,
Chesapeake Bay) is the deposition-
related issue of most concern in the
United States. Adverse environmen-
tal effects include the loss or shift in
number and type of species, and
explosive algae growth leading to a
depletion of oxygen in the water,
and/ or an increase in levels of toxins
harmful to fish and other aquatic life.
Nitrogen oxides are an important
precursor both to ozone and to acidic
deposition (see sections on ozone and
sulfur dioxide trends.) NOx emis-
sions also can have a significant im-
pact on particulate matter
concentrations, most notably in some
western urban areas.
Primary and Secondary Standards
The level for both the primary and
secondary national ambient air quality
standards (NAAQS) for N02 is 0.053
ppm annual arithmetic average, not to
be exceeded.
National 10-Year Trends
The statistic used to track ambient
N02 air quality trends is the annual
mean N02 concentration. A total of
224 ambient N02 monitoring sites
met the trends data completeness
criteria. The national trend in annual
mean N02 concentrations is shown
graphically in Figure 2-17 for the 10-
year period, 1988-1997. Based on
measurements at 224 monitoring sites
located in cities throughout the coun-
try, the 1997 national composite mean
N02 concentration is 14 percent lower
than the composite mean recorded in
1988, and is unchanged from the 1996
level. Figure 2-17 shows that sites
recording the highest annual mean
N02 concentrations (the 90th percen-
tile) have recorded the largest reduc-
tions. Except for 1994, annual mean
N02 concentrations have decreased
yearly since 1989. Figure 2-18 shows
how the trends in annual mean N02
concentrations vary among urban,
suburban and rural monitoring loca-
tions. As Figure 2-18 illustrates, the
highest annual mean N02 concentra-
tions are typically found in urban
areas, with significantly lower annual
20 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
mean concentrations recorded at
rural sites. Trends in annual mean
NO2 concentrations are similar at
both urban and suburban sites. The
1997 composite mean at 80 urban
sites is 19 percent lower than the 1988
level, compared to 17 percent lower
at 96 suburban sites. At 46 rural sites,
the composite mean N02 concentra-
tion decreased in 1990 and remained
constant for the next 4 years. The
1997 composite mean NO2 concentra-
tion at these rural sites is 22 percent
lower than the 1988 composite mean
level. (See Figure B-3 in Appendix B
for a map of the N02 monitoring site
locations.)
Atmospheric concentrations of
N02 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 N02, hence chemi-
luminescence analyzers are subject to
interferences produced by response
to other nitrogen containing com-
pounds (e.g., peroxyacetyl nitrate)
(PAN) which 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, be-
cause there are no violations of the
NO2 NAAQS. In addition, the inter-
ferences are believed to be relatively
small in urban areas.9 The air quality
trends depicted are in urban loca-
tions, and are expected to be reason-
able representations of urban NO2
trends. However, that is not the case
in rural and remote areas where air
mass aging could foster greater rela-
tive levels of PAN and nitric acid and
Figure 2-17. Trend in annual N02 mean concentrations, 1988-1997.
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.00
Figure2-18. Trend in annual mean N02 concentrations by type of location, 1988-1997.
Concentration, ppm
0.03
0.025
0.02
0.015
0.01
0.005
0
88 89 90 91 92 93 94 95 96 97
Concentration, ppm
n~90th Percentile
-Mean
-Median
—10th Percentile
224 Sites
NAAQS
88 89 90 91 92 93 94 95 96 97
Rural (46 sites) Suburban (96 sites) Urban (80 sites)
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 21
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-19. Trend in national total NOx emissions, 1988-1997.
Thousand Short Tons Per Year
30,000
25,000
20,000
15,000
10,000
5,000
0
88 89 90 91 92 93 94 95 96 97
~ Fuel Combustion I Industrial Processing
~ Transportation ~ Miscellaneous
Figure 2-20. NOx emissions by source category, 1997.
Fuel Combustion
45.4%
Industrial Processes
3.9%
Miscellaneous
1.5%
Transportation J
49.2%
interfere significantly with the inter-
pretation of N02 monitoring data.
Emissions Trends
Figure 2-19 shows the 10-year trend
in NOx emissions. National total NOx
emissions in 1997 are 1 percent lower
than the 1988 total, although changes
in data availability and methodology
between 1989 and 1990 (in the other
combustion category) introduce some
uncertainty in this comparison.
Emissions from fuel combustion
sources are 2 percent higher than the
1988 level, but 4 percent lower than
the peak emissions of 1993. Figure 2-
20 shows that the two primary
sources of NOx emissions are fuel
combustion and transportation. To-
gether these two sources comprise 95
percent of 1997 total NOx emissions.
Because most \'02 monitors are lo-
cated in urban, population-oriented
areas, that are dominated by mobile
sources, the reduction in ambient
concentrations (a 14-percent decrease
since 1988) more closely tracks the 8-
percent decrease in NOx emissions
from highway vehicles. As noted
previously in this report, VMT in-
creased 25 percent nationally during
the past 10 years. Emissions from
coal-fired electric utilities account for
roughly one quarter of all NOx emis-
sions and are not likely to impact
most urban \02 monitoring sites.
Between 1988 and 1997, emissions
from these sources decreased 1 per-
cent. Title IV (Acid Deposition Con-
trol) of the CAA provides a guideline
for NOx reductions of approximately
two million tons from 1980 emissions
levels. In 1997, NOx emissions were
reduced 32 percent from 1990 levels
at 263 coal-fired units under Phase I
of the Acid Rain NOx Control Pro-
gram.9 These units accounted for
22 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-21. Long-term trend in annual mean N02 concentrations, 1978-1997.
1978-87 1988-97
(93 sites) (224 sites)
78 80 82 84 86 88 90 92 94 96
over three percent of total national
NOx emissions in 1997. Between 1996
and 1997, NOx emissions from these
sources increased 1 percent due to
greater electrical production.10 Table
A-4 provides a listing of NOx emis-
sions by major source category.
The significance of the role of ni-
trogen oxides as a precursor to ozone
formation was addressed in a final
rule published by EPA in October
1998 (commonly known as the NOx
SIP Call). The rule calls for reduc-
tions in summertime NOx emissions
to reduce the regional transport of
ozone11 and set (1) a model cap-and-
trade program, (2) revised statewide
NOx emission budgets, and (3) pro-
posed revisions to the Acid Rain Pro-
gram.11 Although the rule does not
mandate which sources must reduce
emissions, EPA has estimated that
reducing NOx emissions from utilities
and large non-utility point sources is
one cost-effective strategy available
to states. See the ozone section for
more information concerning this
rule.
National 20-Year Trends
As discussed previously, long-term
national ambient air quality trends
are difficult to assess because few
monitoring sites have operated con-
tinuously in the same location for 20
years. Figure 2-21 presents 20-year
trends in ambient NOo concentrations
by combining two separate 10-year
trends databases, 1978-1987 (93 sites)
and 1988-1997 (224 sites). Nationally,
annual mean NOo concentrations
have decreased in urban areas by
approximately 2 percent since 1978.
As seen in Figure 2-21, annual mean
NOo concentrations declined in the
early 1980s, were relatively flat dur-
ing the mid-to-late 1980s, and re-
sumed their decline in the 1990s. The
1997 national composite mean NOo
Concentration, ppm
0.03
0.025
0.02
0.015
0.01
0.005
0
concentration is the lowest level re-
ported during the past 20 years.
Regional Trends
The map in Figure 2-22 shows the
trends in NOo concentrations during
the past 10 years, 1988-1997. The
trends statistic is the regional com-
posite mean of the NOo annual mean
concentrations across all sites with at
least 8 years of ambient measure-
ments. Every EPA region (except
Region 10 which does not have any
NOo trend sites) recorded 10-year
declines in composite annual mean
NOo concentrations. Figure 2-22
shows that the largest reductions in
composite annual mean NOo concen-
trations occurred in Region 9 (the
South Coast of California), followed
by Region 1 (the New England
states), and the Region 2 states of
New York and New Jersey.
All monitoring locations across the
nation, including Los Angeles, met
the NOo NAAQS in 1997. This is
reflected on the map in Figure 2-23
that displays the highest annual
mean NOo 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 NOo)
to attainment for the NOo NAAQS.12
Data Sources
The NOo 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 NOo concentra-
tion by county in 1997.
1997 Air Quality Status
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 23
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-22. Trend in N02 maximum quarterly mean concentrations by EPA Region, 1988-1997.
Insufficient
Trend Data
¦f 7%
#¦4%
f 19%
-f- 20%
J 26%
¦f 6%
_M5
¦f 12%
¦f 12%
The National Trend
J)21_
#¦ 14%
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.
Figure 2-23. Highest N02 annual mean concentration by county, 1997
Concentration (ppm)
24 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Ozone
• Air Quality Concentrations
1988-97
19% decrease (1-hr)
16% decrease (8-hr)
1996-97
no change (1-hr)
1 % decrease (8-hr)
• Emissions
1988-97
20% decrease
1996-97
no change
Nature and Sources
Ground level ozone has remained a
pervasive pollution problem through-
out the United States. Ozone is
formed readily 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 natural (bio-
genic) sources. NOx is emitted from
motor vehicles, power plants, other
sources of combustion and natural
sources including lightning and bio-
logical processes in soil. Changing
weather patterns contribute to yearly
differences in ozone concentrations.
Ozone and the precursor pollutants
that cause ozone also can be trans-
ported into an area from pollution
sources found hundreds of miles
upwind.
Health and Environmental Effects
Ozone occurs naturally in the strato-
sphere and provides a protective
layer high above the Earth. At
ground-level however, 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 can make
people more susceptible to respira-
tory infection, result in lung inflam-
mation, and aggravate pre-existing
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 (e.g., outdoor work-
ers) and individuals with pre-existing
respiratory disease such as asthma
and chronic obstructive lung disease;
within each group there are individu-
als who are unusually responsive to
ozone. In addition, long-term expo-
sures to ozone present the possibility
of irreversible changes in the lungs
which could lead to premature aging
of the lungs and/ or chronic respira-
tory illnesses.
Ozone also affects vegetation
and ecosystems, leading to reduc-
tions in agricultural and commercial
forest yields, reduced growth and
survivability of tree seedlings, and
increased plant susceptibility to dis-
ease, pests, and other environmental
stresses (e.g., harsh weather). In long-
lived species, these effects may be-
come evident only after several years
or even decades, thus, having the
potential for long-term effects on
forest ecosystems and habitat quality
for wildlife and endangered species.
Further, 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 pri-
mary NAAQS is 0.12 ppm daily
maximum 1-hour 03 concentration
that is not to be exceeded more than
once per year on average. The sec-
ondary standard is identical to the
primary standard. To encourage an
orderly transition to the revised O3
standards, the 1-hour standards will
no longer apply to an area once EPA
determines that the area has air qual-
ity data meeting the 1-hour stan-
dards. In 1998, EPA revoked the
1-hour O3 NAAQS in 2918 counties in
the United States leaving 225 counties
where the 1-hour standard still ap-
plies.13,14
Primary and Secondary 8-hour
Ozone Standards
On July 18,1997, EPA established an
8-hour O3 primary standard to pro-
tect against longer exposure periods
that are of concern for both human
health and welfare (vegetation).15
The level of the national 8-hour pri-
mary and secondary ambient 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 an-
nual fourth-highest daily maximum
8-hour ozone concentration is less
than or equal to 0.08 ppm.15 EPA will
designate ozone nonattainment areas
for the 8-hour ozone NAAQS by July,
2000.16
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 25
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-24. Trend in annual second-highest daily maximum 1 -hour 03
concentrations, 1988-1997.
Concentration, ppm
-90th Percentile
-Mean
Median
-10th Percentile
660 Sites
NAAQS
88 89 90 91 92 93 94 95 96 97
National 10-Year Trends
Because the 1-hour and 8-hour
NAAQS have different averaging
times and forms, two different statis-
tics are used to track ambient O3 air
quality trends. For the 1-hour O3
NAAQS, Figure 2-24 presents the
national trend in the annual second-
highest daily maximum 1-hour O3
concentration at 660 monitoring sites.
The inter-site variability for annual
second highest daily maximum 1-
hour 03 concentrations is graphically
shown by the 90th percentile, me-
dian, composite mean, and 10th per-
centile concentrations in Figure 2-24.
This figure shows that during the
past 10-years, higher concentrations
have declined more rapidly (the 90th
percentile concentration is down 28
percent), while the 1997 national
composite average daily maximum 1-
hour ozone concentration is 19 per-
cent lower than the 1988 level. The
composite mean concentration is
unchanged between 1996 and 1997.
Although not shown, the com-
posite average estimated exceedance
rate (i.e., the average number of days
when the daily maximum 1-hour
average concentration exceeds the
level of the 1-hour NAAQS) has de-
clined 86 percent since 1988. 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. Be-
tween 1996 and 1997, the national
composite mean of the average num-
ber of exceedances of the ozone
NAAQS declined 30 percent, prima-
rily as a result of the 61 percent de-
crease in the exceedance rate at sites
in California.
For the 8-hour ozone NAAQS,
Figure 2-25 presents the trend in the
0.25
0.20
0.15
0.10
0.05
0.00
annual fourth-highest 8-hour daily
maximum O3 concentration at the
same 660 sites. The trend in the
8-hour O3 statistic is similar to the
1-hour trend, although the concentra-
tion range is smaller. As measured by
the composite mean concentration
across all 660 sites, annual fourth-
highest 8-hour average concentra-
tions decreased 16 percent since the
peak year of 1988. Although, the 8-
hour national composite mean con-
centration decreased 1 percent
between 1996 and 1997, the higher
concentration sites, as shown by the
90th percentile concentrations, in-
creased 2 percent since 1996.
Ambient O3 trends are influ-
enced by year-to-year changes in
meteorological conditions, popula-
tion growth, VOC to NOx ratios, and
changes in emissions from ongoing
control measures. This 10-year trends
period, with peak ozone years at both
endpoints, demonstrates the impor-
tance of accounting for year to year
variability in meteorological condi-
tions when assessing ozone
trends.17,18 Previous Trends Reports
have discussed an EPA statistical
model, based on the Weibull prob-
ability distribution, that attempts to
account for meteorological effects and
helps to normalize the resulting trend
estimates across years.18 The model,
applied on an individual metropoli-
tan area basis, includes a trend com-
ponent that adjusts the annual rate of
change in ozone for concurrent im-
pacts of meteorological conditions,
including surface temperature and
wind speed. Figure 2-26 displays the
model results for both the 1-hour and
8-hour trends statistics averaged
across 41 metropolitan areas. While
the ambient monitoring data reflect
the year-to-year variability in ozone
conducive conditions, the meteoro-
logically adjusted ozone trend pro-
vides a better indicator of the impact
26 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
of emissions changes. For these 41
metropolitan areas, the adjusted
trend for both averaging times shows
continued improvement with an
average decrease in O3 concentrations
of about 1 percent per year since
1986.
Figure 2-27 shows the 10-year
change in ambient ozone concentra-
tions among urban, suburban and
rural monitoring sites. The highest
ambient O3 concentrations are typi-
cally found at suburban sites, consis-
tent with the downwind transport of
emissions from the urban center.
During the past 10 years, the compos-
ite mean O3 concentration decreased
23 percent at 117 urban sites and
declined by 21 percent at 292 subur-
ban sites. The 1997 composite mean
concentration at 234 rural sites is 17
percent lower than the 1988 level.
EPA also announced that it
intends to expand the rural ozone
monitoring network and to explore
opportunities to work with other
federal agencies to develop a coordi-
nated and long-term rural monitoring
network.15 One of the ways EPA is
accomplishing this is the Clean Air
Status and Trends Network
(CASTNet) which was developed in
response to the CAAA of 1990 requir-
ing implementation of a national
network to measure national status
and trends. The CASTNet O3 net-
work, which consists of a total of 69
sites (50 CASTNet and 19 National
Park Service (NPS) sites), was de-
signed, in part, to provide informa-
tion on the distribution of O3 across
rural areas of the United States.
CASTNet sites are consid-
ered regionally representative, and
thus able to define geographic pat-
terns of rural ozone across the United
States. Meteorological variables also
are recorded continuously and
Figure 2-25. Trend in annual fourth-highest daily maximum 8-hour 03 concentrations,
1988-1997.
0.25
0.20
0.15
0.10
0.05
0.00
Figure 2-26. Comparison of actual and meteorologically adjusted trends in 1 -hour and
8-hour 99th percentile 03 concentrations, 1988-1997.
Concentration, ppm
0.20
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
86 87 88 89 90 91 92 93 94 95 96 97
Concentration, ppm
90th Percentile
-Mean
-Median
-10th Percentile
660 Sites
NAAQS
88 89 90 91 92 93 94 95 96 97
1-hour Actual
1-hour Met Adjusted
\ 8-hour Actual
8-hour Met Adjusted
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 27
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-27. Trend in annual second-highest daily maximum 1 -hour 03 concentrations
by location, 1988-1997.
Concentration, ppm
0.20
0.15
0.10
0.05
0.00
Rural (234 sites) Suburban (292 sites) Urban (117 sites)
88 89 90 91 92 93 94 95 96 97
Figure 2-28. Trend in annual fourth-highest daily maximum 8-hour 03 concentrations
in National Parks, 1988-1997.
Concentration, ppm
0.20
0.18
0.16
0.14
0.12
0.10
0.08 — | 8-hr NAAQS
0.06
0.04
0.02
0.00
National Trend
National Park Sites (24 sites)
reported as hourly averages.
See Chapter 7: Acid Deposition for
more information concerning
CASTNet.
Because several other federal
agencies have a similar need to un-
derstand how ozone impacts the
resources they manage, EPA is also
working with these agencies to iden-
tify better ways to leverage existing
monitoring and data collection and
analysis efforts. For example, a spe-
cial subset of rural environments, all
national parks and wilderness areas
exceeding 5,000 acres, were desig-
nated as Class I areas in the 1977
amendments to the CAA. These
areas are accorded a higher degree of
protection under the CAA provisions
for the prevention of significant dete-
rioration. The CAA further directs
the federal land managers to protect
air-quality related values (AQRVs).
Sufficient monitoring data are avail-
able to assess 10-year trends in ambi-
ent O3 concentrations at 24 NPS sites.
Figure 2-28 compares the 10-year
trend in the composite mean of the
annual fourth highest 8-hour O3 con-
centration at these 24 Class I sites
with the national O3 trend. Non-
parametric regression was used to
assess the statistical significance of
the 10-year trend in 8-hour ozone
concentrations for the composite
mean across all 24 NPS sites, and at
each of the NPS sites. Although the
1997 composite mean O3 concentra-
tions is 8 percent lower than the
1988 value, there is no statistically
significant trend in the composite
mean O3 concentration at these NPS
sites. On an individual site basis,
only two sites, both in the Great
Smoky Mountains National Park, had
statistically significant upward
trends. Although not statistically
88 89 90 91 92 93 94 95 96 97
28 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-29. Metropolitan areas subject to the PAMS program.
Santa Barl
Ventura Cou
Los Angel
San Joaq
Southeast Desert
Providence
Greater Connecticut
NewYork
Philadelphia
Dallas - Ft. Worth
Houston ¦
LEGEND:
~ — Existing Areas Subject to PAMS Requirements
~ — Operational #1, #3, & #4 Sites for 1998
~ — Operational #2 Sites for 1998
~ — New PAMS Areas for 1998
significant, of the remaining 22 sites,
11 sites had downward slopes, 8 up-
ward and 3 sites showed no change.
(See Chapter 3: Criteria Pollutants -
Metropolitan Area Trends, for a de-
scription of the non-parametric re-
gression procedure.)
Enhanced Ozone Monitoring (PAMS)
Section 182(c)(1) of the CAA called
for improved monitoring of ozone
and its precursors, VOC and NOx, to
obtain more comprehensive and rep-
resentative data on ozone air pollu-
tion. Responding to this requirement,
EPA promulgated regulations in Feb-
ruary 1993 to initiate the Photochemi-
cal Assessment Monitoring Stations
(PAMS) program.19 The PAMS pro-
gram requires the establishment of an
enhanced monitoring network in all
ozone nonattainment areas classified
as serious, severe, or extreme. Cur-
rently, 24 of the remaining 38
nonattainment areas for the 1-hour O3
NAAQS are subject to PAMS; these
areas are identified in Figure 2-29.
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, topogra-
phy, and relative proximity to emis-
sions sources of VOC and NOx. Each
PAMS network generally consists of
four different types of monitoring
sites (Types 1, 2,3, and 4) designed to
fulfill unique data collection objec-
tives. Type 1 sites are located upwind
of the metropolitan area to measure
ozone and precursors being trans-
ported into the area. Type 2 sites,
referred to as maximum precursor
emissions impact sites, are designed
to collect data on the type and magni-
tude of ozone precursor emissions
emanating from the metropolitan
area and are typically located imme-
diately downwind of the central busi-
ness district. Type 3 stations are in-
tended to measure maximum ozone
concentrations and are sited farther
downwind of the urban area than the
Type 2 sites. Type 4 PAMS sites are
located downwind of the nonattain-
ment area to assess ozone and precur-
sor levels exiting the area and
potentially contributing to the ozone
problem in other areas. In addition to
the surface monitoring sites, each
PAMS area also is required to monitor
upper air meteorology at one repre-
sentative site.
Regulations allow a 5-year
transition or phase-in schedule for
the program at a rate of at least one
station per area per year. The first
official year of implementation for
PAMS was 1994. As of August 1998,
there were 78 operating PAMS sites.
The data collected at the PAMS sites
include measurements of ozone, NOx,
total non-methane organic com-
pounds (TNMOC), a target list of
VOC species including several carbo-
nyls, plus surface and upper air me-
teorology. Most PAMS sites measure
56 target hydrocarbons on an hourly
or 3-hour basis during the PAMS
monitoring season. Included in the
monitored VOC species are 10 com-
pounds classified as hazardous air
pollutants (HAPs). The PAMS pro-
gram is the only federally mandated
initiative that requires routine moni-
toring of HAPs; for more information
on HAPs see Chapter 5: Air Toxics.
All PAMS stations measure ozone,
NOx, and surface meteorological
parameters on an hourly basis. In
general, the PAMS monitoring season
spans the three summer months
when weather conditions are most
conducive for ozone formation. EPA
allows states flexibility in network
design and sampling plans in recog-
nition of the fact that each PAMS area
has its own unique characteristics
and demands. For more information
on the PAMS networks, data col-
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 29
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 2-3. Summary of changes in 03, NOx and TNMOC at PAMS sites, 1996-1997.
Number of Sites
Median
Pollutant
Total
Up
Down
Percent
Change
03 2nd daily
max 1-hr
69
-
-
1%
NOx—Summer
6-9am mean
52
8
9
0%
TNMOC—Summer 42
6-9am mean
8
9
-2%
Note: The numbers shown in the "Up" and "Down" categories refer to the number of
sites in which the change in summer 6-9am, mean concentrations between the years
referenced is a statistically significant increase or decrease (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.
Figure 2-30. National total VOC emissions trend, 1988-1997.
I~1 Fuel Combustion I Industrial Processing
~ Transportation ~ Miscellaneous
Thousand Short Tons Per
35,000
30,000
25,000
20,000
15,000
10,000
5,000
0
88 89 90 91
lected, and analyses of the data, see
the EPA PAMS web site at http://
www.epa.gov/oar/oaqps/pams.
PAMS data provide the oppor-
tunity for state and local air pollution
control agencies to effectively evalu-
ate ozone nonattainment conditions,
93 94 95 96 97
confirm attainment/nonattainment
decisions, identify cost-effective con-
trol strategies, evaluate population
risk exposure, and develop ozone
and ozone precursor trends. The
measurements have proven ex-
tremely valuable in verifying ozone
precursor emissions inventories and
in corroborating estimates of area-
wide emissions reductions. The data
can be used to evaluate, adjust, and
provide input to the photochemical
grid models used to develop ozone
control strategies, as well as demon-
strate their success.
Table 2-3 shows second daily
maximum 1-hour O3 concentrations
and summer 6-9am mean NOx and
TNMOC concentrations for all report-
ing PAMS sites for the most recent 2-
year period. Morning periods for
NOx and TNMOC are shown since
those time frames are generally
thought to be an appropriate indicator
of anthropogenic emissions. In gen-
eral, total VOC declined notably
between 1994 and 1997, though most
of the reductions occurred in the first
2 years, especially between 1994 and
1995. Previous editions of the Trends
Report highlighted these reductions
(as well as corresponding declines in
selected VOC species) and attributed
them, at least in part, to mobile
source controls, specifically the
implementation of reformulated
gasoline (RFG). Between 1996 and
1997, total VOC only declined
slightly (2 percent). NOx concentra-
tions at PAMS sites were even flatter.
The median site concentration is
unchanged between 1996 and 1997;
only a third of the reporting sites had
a significant change in either direc-
tion with a fairly even split between
sites that showed increases and those
that showed declines.
Emissions Trends
Figure 2-30 shows that national total
VOC emissions (which contribute to
ozone formation) from anthropogenic
sources decreased 20 percent between
1988 and 1997. National total NOx
emissions (the other major precursor
30 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-31. VOC emissions by source category, 1997.
Fuel Combustion 4.5%
Miscellaneous 4.5%
Industrial Processes 51.2%
Transportation 39.9%
Table 2-4. Biogenic sources of VOC emissions by region.
Region
VOC
Source
Southwestern
Isoprene
Oak (mostly), citrus,
United States
eucalyptus
Monoterpenes
Pine, citrus, eucalyptus
Northeastern
Isoprene
Oak (mostly), spruce
United States
Monoterpenes
Maple, hickory, pine,
spruce, fir, cottonwood
to ozone formation) increased 1 per-
cent between 1988 and 1997. Recent
control measures to reduce emissions
include regulations to lower fuel
volatility and to reduce NOx and
VOC emissions from tailpipes.20 The
effectiveness of these control mea-
sures is reflected in the 28 percent
decrease in VOC emissions from
transportation sources. VOC emis-
sions from highway vehicles have
declined 37 percent since 1988, while
highway vehicle NOx emissions have
declined 8 percent since their peak
level in 1994. Nationally, the two
major sources of VOC emissions are
industrial processes (51 percent) and
transportation sources (40 percent) as
shown in Figure 2-31. Solvent use
comprises 66 percent of the industrial
process emissions category and 34
percent of total VOC emissions. The
emissions totals by source category
and year can be found in Table A-5.
As required by the CAA, a
cleaner burning fuel (RFG) has been
sold since January 1,1995 in those
areas of the country with the worst
ozone or smog problems. RFG is
formulated to reduce automotive
emissions of ozone-forming pollut-
ants and toxic chemicals and is esti-
mated to reduce both VOC and toxic
emissions by more than 15 percent.21
RFG sold during the summer ozone
season has lower volatility than most
conventional gasoline.22 The RFG
program is mandated year-round in
10 areas of the country (Los Angeles,
San Diego, Hartford, New York,
Philadelphia, Chicago, Baltimore,
Houston, Milwaukee, and Sacra-
mento). Besides these required areas,
several other parts of the country
exceeding the ozone standard have
voluntarily entered the RFG pro-
gram.
In addition to anthropogenic
sources of VOCs and NOx, there are
natural or biogenic sources of these
compounds as well. Table 2-3 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
we are not able to control the level of
these natural emissions, when devel-
oping ozone control strategies, their
presence is an important factor to
consider. Biogenic NOx emissions are
associated with lightning and biologi-
cal processes in soil.
On a regional basis, biogenic
VOC emissions can be greater than
anthropogenic VOC emissions. Bio-
genic NOx emissions, on the other
hand, are less than 10 percent of total
NOx emissions. EPA's estimates of
total U.S. VOC emissions from bio-
genic sources are based on the Bio-
genic Emissions Inventory
System—Version 2 (BEIS2).23,24 A
recent national estimate for annual
total biogenic VOCs from vegetation
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 31
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-32. Trend in annual second-highest daily maximum 1 -hour 03 concentrations,
1978-1997.
1978-87 1988-97
(320 sites) (660 sites)
78 80 82 84 86
90 92 94 96
Concentration, ppm
0.15
0.1
0.05
0
is 29 million short tons, while bio-
genic nitric oxide emissions are esti-
mated at 1.5 million short tons.25
Biogenic emissions are influenced by
fluctuations in temperature, with the
highest emissions occurring in the
summer when temperatures are high-
est. For example, an increase of
10 degrees Celsius (°C) can result in
over a two-fold increase in both VOC
and NOx. Research in the area of
biogenic emissions continues, and
changes in emission estimates are to be
expected and should be viewed with
an uncertainty of at least a factor of
two.
National 20-Year Trends
Long-term, quantitative ambient
ozone trends are difficult to estimate
due to changes in network design,
siting criteria, spatial coverage and
monitoring instrument calibration
procedures during the past two de-
cades. For example, in Figure 2-32
the first year of the early trends pe-
riod, 1978, corresponds to the use of
the old calibration procedure where
concentration levels are less certain.
Because only a few sites have moni-
tored continuously for two decades,
the 20-year trends line in Figure 2-32
is composed of two segments; 238
sites with complete data during the
first 10 years, 1978-1987, and 660
sites meeting the data completeness
criteria in the most recent 10 years,
1988-1997. Nationally, peak 1-hour
O3 concentrations, as measured by
the composite mean of the annual
second highest daily maximum 1-
hour O3 concentrations, declined 30
percent since 1978. Figure 2-32 clearly
shows the peak ozone years of 1980,
1983,1988 and 1995.
Regional Trends
The map in Figure 2-32 shows re-
gional trends in 1-hour O3 concentra-
tions during the past 10 years,
1988-1997. The trends statistic is the
composite mean of the annual sec-
ond-highest daily maximum 1-hour
03 concentration averaged across all
sites in each EPA region with at least
eight years of ambient O3 measure-
ments. Figure 2-34 shows the 10-year
trends in the composite mean of the
annual fourth-highest daily maxi-
mum 8-hour concentration. The
trends for both the 1-hour and 8-hour
trends statistics are similar, however,
the magnitude of the reductions is
larger for the annual second-highest
1-hour daily maximum O3 concentra-
tions as compared to the annual
fourth-highest daily maximum 8-
hour concentrations. Every EPA re-
gion recorded 10-year declines in
composite mean 1-hour and 8-hour
peak O3 concentrations.
The greatest improvement in air
quality occurred in Northeast, Mid-
Atlantic, North Central and Pacific
regions. The changes in O3 concen-
trations since last year reflect the
regional differences in meteorological
conditions across the country. Sum-
mer 1997 statewide temperature and
precipitation ranks are shown in
Figure 2-35 based on preliminary
meteorological data available from
National Oceanic aand Atmospheric
Administration (NOAA).26 No state
was within the top ten warm cat-
egory and only eight states ranked
within the warm third of the tem-
perature distribution. Preliminary
data indicate that Summer 1997 was
the sixth coolest on record for Geor-
gia and the ninth coolest since 1895
for both Mississippi and South Caro-
lina. Nine states ranked within the
top ten dry portion of the historical
distribution for Summer 1997 includ-
ing the fourth driest summer since
1895 for Virginia and Maryland and
the fifth driest summer season for
32 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-33. Trend in 03 second maximum 1- hour concentrations by EPA Region, 1988-1997.
# 22%
#17%
#21%
# 27%
#23%
#26%
.111
V
# 15%
#21%
#7%
#12%
The National Trend
.130
# 19%
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.
Figure 2-34. Trend in 03 fourth maximum 8-hour concentration by EPA Region, 1988-1997.
.070 .058
#18% # 22%
#20%
#19%
#7%
#10%
The National Trend
•098
v. .082
#16%
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 33
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
New Jersey. Fifteen other states
ranked within the dry-third of the
distribution. It was the second wet-
test summer since records began for
California and the ninth wettest sum-
mer on record for Montana.26
Addressing The Ozone Transport
Issue
In recognition of long-standing re-
gional ozone problems in the North-
eastern United States, the 1990 CAAA
established the Ozone Transport
Commission (OTC) and the North-
east Ozone Transport Region which
includes 12 states. Since that time,
several other regional groups have
formed to study various aspects of
the problem and to try to identify
acceptable solutions. EPA continues
to be a contributor, partner, or inter-
ested party in each of these efforts.
The most significant recent develop-
ments occurred as a result of a 2-year
effort known as the Ozone Transport
Assessment Group (OTAG), EPA
worked in partnership with state and
local government agencies in the 37
easternmost states, industry, and
academia to address ozone transport.
The extensive modeling analysis
conducted by OTAG showed the
significant contribution of trans-
ported precursor emissions to
nonattainment of the ozone NAAQS.
As a result of OTAG's findings on the
role of nitrogen oxides as a precursor
to ozone formation, EPA published a
rule in October 1998 (commonly
known as the NOx SIP Call) that
called for reductions in summertime
NOx emissions to reduce the regional
transport of ozone.10 The NOx SIP
Call sets (1) a model cap-and-trade
program, (2) statewide NOx emission
budgets, and (3) proposed revisions
to the acid rain program October
1998. More detailed information on
the OTAG process and details on
information generated by the OTAG
workgroups are available on the
OTAG web page at http://
www.epa.gov/ttn/otag.
Other regional groups that have
addressed regional ozone problems
include the Lake Michigan Ozone
Study (LMOS), the Southern Oxidant
Study (SOS), the Southern Appala-
chian Mountain Initiative (SAMI),
and the North American Research
Strategy for Tropospheric Ozone
(NARSTO). For more information on
these groups, see
www.epa.govairprogm/oar/oaqps/
airtrans/regional.html.
1997 Air Quality Status
The map in Figure 2-36 presents the
highest second daily maximum
1-hour concentration by county in
1997. The accompanying bar chart to
the left of the map reveals that in
1997 approximately 48 million people
lived in 77 counties where the annual
second daily maximum 1-hour O3
concentration was above the level of
the 1-hour ozone NAAQS. These
numbers represent an increase from
the totals reported last year (39 mil-
lion people living in 52 counties) with
ozone concentrations above the level
of the ozone NAAQS in 1996. As
noted previously, meteorological
conditions in some regions of the
country were
more conducive to peak O3 formation
in 1997, than in 1996. The map in
Figure 2-36 shows large spatial differ-
ences, with higher O3 concentrations
typically found in Southern Califor-
nia, the Gulf Coast, and the Northeast
and Northcentral states. Historically,
the highest 1-hour concentrations are
found in Los Angeles, however, 1997
is the first year that the highest 1-
hour concentrations in Houston ex-
ceeded the levels recorded in Los
Angeles.
34 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-35. Summer 1997 statewide temperature ranks (Source: NOAA, 1997).
43
40
48
Temperature
Note: 1 = coldest/driest ; 103 = warmest/wettest
40
102
Precipitation
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 35
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-36. Highest second daily maximum 1 -hour 03 concentration by county, 1997
Concentration (ppm)
36 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Particulate Matter
• Air Quality Concentrations
1988-97 26% decrease
1996-97 1% decrease
• Emissions
1988-97 12% decrease
1996-97 1% decrease
Nature and Sources
PM is the general term used for a
mixture of solid particles and liquid
droplets found in the air. These par-
ticles, which come in a wide range of
sizes, originate 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 atmo-
sphere by the transformation of gas-
eous precursor emissions such as S02
and NOx (secondary particles). Their
chemical and physical compositions
vary depending on location, time of
year, and meteorology.
Health and Environmental Effects
Scientific studies show a link between
inhalable PM (alone, or combined
with other pollutants in the air) and a
series of significant health effects.
Inhalable PM includes both fine and
coarse particles. "Fine" particles are
those that are less than 2.5 microme-
ters in diameter. Those between 2.5
and 10 micrometers are known as
"coarse" particles. Both coarse and
fine particles can accumulate in the
respiratory system and are associated
with numerous health effects. Expo-
sure to coarse fraction particles is
primarily associated with the aggra-
vation of respiratory conditions such
as asthma. Fine particles are most
closely associated with such health
effects as decreased lung function,
increased hospital admissions and
emergency room visits, increased
respiratory symptoms and disease,
and premature death. Sensitive
groups that appear to be at greatest
risk to such effects include the eld-
erly, individuals with cardiopulmo-
nary disease including asthma, and
children.
In addition, PM causes ad-
verse impacts to the environment.
Fine PM is the major cause of
reduced visibility in parts of the
United States, including many of
our National Parks. Other environ-
mental 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 composition and
buffering capacity change. An
ecosystem condition known as
"nitrogen saturation," where
additions 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
directly onto the leaves of plants
can, depending on their chemical
composition, corrode leaf surfaces
or interfere 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 damage to
materials, including culturally
important objects such as carved
monuments and statues.
Primary and Secondary PM10
Standards
The PM trends reported here are
based primarily on data collected
when the previous NAAQS were in
effect. These standards include both
short- and long-term PM10 NAAQS.
The long-term standard specifies an
expected annual arithmetic mean not
to exceed 50 ng/ m3 averaged over
three years. The short-term (24-hour)
standard of 150|xg/m3 is not to be
exceeded more than once per year on
average over 3 years. Together, these
were the previous primary, or
health-based, PM10 standards. The
secondary, or welfare-based, stan-
dards for PMjo were identical to the
primary standards.
The original standards for PM,
established in 1971, were for total
suspended particulate (TSP) matter.
In 1987, EPA replaced the TSP
standards with PM10 standards to
focus on smaller particles of aerody-
namic diameter less than or equal to
10 micrometers. These smaller
particles caused the greatest health
concern because of their ability to
penetrate into sensitive regions of
the respiratory tract. The most
recent review of the PM standards
concluded that still more protection
from adverse health effects was
needed. In July 1997, the primary
(health-based) PM standards were
revised to add two new PM25
standards, set at 15|ag/m3 and 65
jag/ m3, respectively, for the annual
and 24-hour standards, and to
change the form of the 24-hour PM10
standard.30 The secondary
(welfare-based) standards were
revised by making them identical to
the primary standards.30 The trends
discussion of this section will focus
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 37
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
on the PM10 standards that were in
place when the majority of the
1988-1997 data presented in this
report were collected.
National 10-Year Trends
The first complete year of PM ]n trends
data for most monitors is 1988, so this
is the first time that the Trends Report
has been able to present a full 10-year
air quality trend for PM10. Figure 2-37
shows a 26-percent decrease in the
composite average of annual mean
PM10 concentrations measured at 845
monitoring sites across the country
between 1988 and 1997. The down-
ward trend in PMjo annual means is
apparent, with a leveling off of the
trend occurring in the later years.
Several factors have played a role in
reducing PM10 concentrations since
1988. Where appropriate, states re-
quired emissions from industrial
sources and construction activities to
be reduced to meet the PM10 stan-
dards. Measures were also adopted
to reduce street dust emissions, in-
cluding 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 and industrial and
electric utility furnaces. The final year
change, between 1996 and 1997,
shows a decrease of 1 percent. This
same general trend can be seen if the
sites are grouped as urban, suburban,
and rural, as in Figure 2-38. The
highest values are generally found at
the urban sites, followed closely by
the suburban sites. The PMio com-
posite annual mean is significantly
lower at the rural sites, which are
Figure 2-37. Trend in annual mean PM10 concentrations, 1988-1997.
70
60
50
40
30
20
10
0
Figure 2-38. PM10 annual mean concentration trends by location, 1988-1997.
Concentration, |jg/m3
35
30
25
20
15
10
5
0
88 89 90 91 92 93 94 95 96 97
Concentration, |jg/m3
n—90th Percentile
>f<-Mean
HVledian
—I—10th Percentile
845 Sites
NAAQS
88 89 90 91 92 93 94 95 96 97
Rural (112 sites) Suburban (329 sites) Urban (385 sites)
38 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
generally located away from local
sources of PM10.
Emissions
Nationally, PM ]n direct emissions
decreased 12 percent between 1988
and 1997 (see Figure 2-39). Emissions
of SOz, a precursor of PM in the at-
mosphere, have also been reduced
nationally, by 11 percent.
Direct PM10 emissions are
generally examined in two separate
groups. The first group, shown in
Figures 2-39 and 2-40, is the more
traditionally inventoried sources.
These include fuel combustion,
industrial processes, and transporta-
tion. Of these, the fuel combustion
category saw the largest decrease
over the 10-year period (-20 per-
cent), with most of the decline
attributable to a decrease in emis-
Figure 2-39.
primary
Thousand Short Tons Per Year
4,000
3,000
2,000
1,000
0
88 89 90 91 92
sions from residential wood burn-
ing. Local control programs to
curtail the use of residential wood
heaters during times when the air
was stagnant and to replace old
woodstoves with new, cleaner-
burning models are responsible for
the decrease in residential wood
burning, along with lower natural
gas and fuel oil prices. Emissions
from industrial processes changed
very little over the 10-year period,
while the transportation category
decreased 14 percent. The second
group of direct PM10 emissions is a
combination of miscellaneous and
natural sources including agricul-
ture and forestry, wildfires and
managed burning, fugitive dust
from paved and unpaved roads, and
wind erosion. As Figure 2-41 shows,
93 94 95 96 97
these miscellaneous and natural
sources actually account for about
90 percent of the total direct PM10
emissions nationwide, although
they can be difficult to quantify
compared to the traditionally
inventoried sources. Because the
emissions in the miscellaneous/
natural group tend to fluctuate a
great deal from year to year, the
trend from one year to the next or
over several years may not be
particularly meaningful.
Table A-6 lists PM10 emissions
estimates for the traditionally
inventoried sources for 1988-1997.
Miscellaneous and natural source
PM10 emissions estimates are
provided in Table A-7.
Regional Trends
Figure 2-42 is a map of regional
trends for the PMio annual mean
from 1988 to 1997. All ten EPA re-
gions show decreasing trends over
the 10-year period, ranging from 19
to 33 percent. The largest decreases
are generally seen in the western part
of the United States, and the two
westernmost regions, IX and X,
started at the highest annual mean
concentrations back in 1988. In the
western states, programs such as
those with residential wood heaters
and agricultural practices have
helped reduce emissions of PMio-
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 PMio
emissions. The program has reduced
S02 and NOx emissions, both precur-
sors of particulate matter in the atmo-
sphere (see the section on S02 in this
National PM10 emissions trend, 1988-1997 (traditionally inventoried
PM sources only).
n Fuel Combustion I Industrial Processing Q Transportation
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 39
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
chapter for more on the Acid Rain Figure 2-40. PM10 emissions from traditionally inventoried source category, 1997.
Program).
1997 Air Quality Status Fuel Combustion 34 9%
The map in Figure 2-43 displays the
highest second maximum 24-hour
PM10 concentration by county in
1997. The highest second maximum
was recorded in Howell County, Mis-
souri at a monitor adjacent to a char-
coal kiln facility. The bar chart which
accompanies the national map shows
the number of people living in coun-
ties within each concentration range.
The colors on the map and bar chart
correspond to the colors of the con-
centration ranges displayed in the
map legend. In 1997, approximately
5 million people lived in 10 counties
where the second highest maximum
24-hour PM10 concentration was
above the level of the 24-hour PMjo
NAAQS. When both the current an-
nual and 24-hour standards are con-
sidered, there were 8 million people
living in 13 counties with PMjo con-
centrations above the PM10 NAAQS
in 1997.
The Revised Standards
The form of the 24-hour PMjo stan-
dard changed from the one-
expected-exceedance form to a
concentration-based 99th percentile
form, averaged over 3 years. EPA
changed the form of the 24-hour PMjo
standard from an expected-exceedance
form to a concentration-based form
because the new form relates more
directly to PM concentrations associ-
ated with health effects. The
concentration-based form also avoids
exceedances, regardless of size, from
being counted equally in attainment
tests. The method for computing the
99th percentile for comparison to the
24-hour standard is found in the
Transportation 23.0%
Industrial Processes 42.0%
Figure 2-41. Total PM10 emissions by source category, 1997.
Other Combustion 3.0% Agriculture & Forest 14.0%
Wind Erosion 15.8%
Fugitive Dust 57.9% \ \ / Traditionally Invent 9.3%
40 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-42. Trend in PM10 annual mean concentration by EPA Region, 1988-1997.
# 33%
f'32%
33.7
#¦ 27%
24.8
^19%
f'22%
¦f 28%
#¦ 23%
f' 22%
32.5
The National Trend
32.4
29.6
f' 24%
f< 23%
¦f 26%
Alaska is in EPA Region 10; Hawaii, EPA Region 9; and Puerto Rico, EPA Region 2.
Concentrations are ug/m3.
Figure 2-43. Highest second maximum 24-hour PM10 concentration by county, 1997.
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.
180
170
160
150
140
130
120
110
100
i
Concentration (ug/m3)
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 41
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Code of Federal Regulations (40 CFR
Part 50, Appendix N).
The form of the 24-hour PM25
standard is also a percentile form,
although it is a 98th percentile. Like
PM10, it is averaged over 3 years.
The form of the annual standard for
PM25 is a 3-year average of the
annual arithmetic mean, just as for
the PM10 standard. However, unlike
PM10, compliance with the PM25
annual standard may be judged
from single or multiple
community-oriented monitors
reflective of a community-based
spatial average. A spatial average
can be more representative of
community-wide ambient PM
exposures.
Beginning in 1998, the revised
PM standards require that measure-
ments be reported at conditions of
local temperature and pressure
(LTP). This is a change from the
way PM10 data are reported under
the pre-existing standards, which
specify standard temperature and
pressure (STP) for measurement
reporting. High altitude or cold
regions will see the biggest changes
in their concentration levels using
LTP, but all monitoring locations
will probably see some difference.
Sampling frequencies will
change at some locations due to the
revised PM standards. New mini-
mum sampling frequency require-
ments are specified. The number of
samples collected in a year has an
effect on which concentration value
will correspond to the 98th or 99th
percentile (i.e. the maximum
concentration value collected, the
second maximum, and so on). More
frequent sampling is desirable
because it can force the 98th or 99th
percentile to be a value less than the
max, making the statistic more
stable.
Characterizing PM10 Trends Under
the Revised Standards
Figure 2-44 shows a 10-year trend of
the average 99th percentile for 845
sites across the country. The 99th
percentile shown in the trend is com-
puted by the Aerometric Information
Retrieval System (AIRS). The current
AIRS uses a slightly different algo-
rithm to compute a 99th percentile
than the Code of Federal Regulations
(CFR) specifies. The next version of
AIRS will correct this inconsistency.
Meanwhile, the resulting difference
between the two algorithms is insig-
nificant when computing a trend of
845 sites such as Figure 2-43. Any
comparisons to the standards for
compliance purposes would of course
need to use the algorithm specified in
the CFR. The trend data show a
25-percent decrease in average 99th
percentile concentration between
1988 and 1997.
Characterizing PM25 Trends Under
the Revised Standards
A trend of PM2 5 ambient concentra-
tion data is not presented here be-
cause there are not enough monitors
in place at this time to portray an
accurate national trend of urban air
quality. The network of monitors
required for the new PM25 standard
will be phased in over the next few
years. For a look at spatial patterns
and trends in fine particle concentra-
tions, the reader is directed to the
chapter on visibility which docu-
ments data derived from the IM-
PROVE aerosol network. These data
are derived from a sampler which is
not a Federal Reference Method
(FRM) sampler for PM2.5- The data
provide a good estimate of urban and
nonurban concentrations; however,
these data cannot be used for compli-
ance determinations and should be
used for preliminary assessments
only.
In order to get some idea of the
nature of fine PM, some emissions
information coupled with ambient
data measurements can be exam-
ined. EPA is working to improve its
PM25 emission inventory. In the
meantime, a general assessment of
the emission sources contributing to
PM25 can be obtained by evaluating
PM25 monitoring data. The para-
graphs below provide a broad
overview of the nationwide concen-
trations, composition, and sources
of PM25 based on actual PM25
measurements and the emission
inventory of sources contributing
within each composition category.
PM25 is composed of a mixture
of particles directly emitted into the
air and particles formed in the air
from the chemical transformation of
gaseous pollutants. The principal
types of secondary particles are
ammonium sulfate and ammonium
nitrate formed in the air from
gaseous emissions of S02 and NOx,
reacting with NH3. The main source
of S02 is combustion of fossil fuels
in boilers (including electric utili-
ties), and the main sources of NOx
are combustion of fossil fuel in
boilers and mobile sources. Some
secondary particles are also formed
from volatile organic compounds
which are emitted from a wide range
of combustion and other sources.
The principal types of directly
emitted particles are those that
predominantly consist of crustal
materials and those consisting of
elemental and organic carbonaceous
materials resulting from the incom-
42 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-44. PM10 trend in the average 99th percentile concentration, 1988-1997.
200
175
150
125
100
75
50
25
0
88 89 90 91 92 93 94 95 96 97
Concentration, |jg/m3
,-|-90th Percentile 845 Sites
-Mean
--Median
LI—10th Percentile NAAQS
plete combustion of fossil fuels and
biomass materials. The main
sources of crustal particles are roads,
construction and agriculture. The
main sources of combustion-related
particles are mobile sources such as
diesels, managed burning, open
burning, residential wood combus-
tion, and utility, commercial, and
industrial boilers.
Figure 2-45 summarizes
information from actual measure-
ments of ambient PM25. It shows
how PM25 composition varies in
both the eastern and western United
States. The ambient samples were
chemically analyzed to determine
the amount of ammonium sulfate
and nitrate, crustal material and
carbonaceous material. The concen-
tration and composition data are
based on at least one year of data
from each monitoring location. The
data were collected using a variety
of non-federal reference methods
and cannot be used to determine
compliance with the PM2 5 NAAQS.
The figure shows the composi-
tion of PM25 in both urban and
nonurban areas of the United States.
The composition information
represents a range of urban and
nonurban locations. The published
composition data for the East are
somewhat limited, but preliminary
information from several recently
completed urban studies is in-
cluded. It shows relatively consis-
tent composition of PM25 across
much of the East. The available
information consistently shows that
PM25 in the East is dominated by
ammonium sulfate on a regional
scale and also by carbonaceous
particles emitted directly by com-
bustion processes. Regional concen-
trations of PM2 5 are generally higher
throughout much of the East, due to
the regional influence of ammonium
sulfate caused by higher S02
emissions throughout much of the
East and the ubiquitous nature of
combustion processes. (See Chapter
7: Acid Deposition for a description
of spatial patterns and trends in
sulfate air quality.) The regional
concentrations of PM2 5 are lower in
the western United States than in
the East and the composition is
more variable. The West differs
from the East in two important
ways. First, nonurban PM25 concen-
trations are much lower in the West
than in the East. This is because the
East is blanketed regionally by
relatively higher concentrations of
ammonium sulfate, whereas re-
gional sulfate concentrations in the
West are much lower. Second,
several western areas, notably the
San Joaquin Valley and the
Rubidoux area of the South Coast
basin have higher ammonium
nitrate concentrations. Nitrate
concentrations are also higher in
nonurban areas of Southern Califor-
nia inland from the South Coast
basin. Such pockets of high nitrate
concentrations have not been
reported in the East. Crustal
material is a relatively small con-
stituent of PM25 in both the West
and East, even in arid and agricul-
tural areas such as Phoenix (Ari-
zona) and the San Joaquin Valley of
California.
Figure 2-46 depicts the link
between sources and the composi-
tion components of PM25. The EPA
has developed a National Emissions
Trends (NET) inventory for use in
analyzing trends in emissions over
time, conducting various in house
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 43
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
analyses for PM, and for use in
regional scale modeling .3I The
NET covers all 50 states and in-
cludes point, area, on-road mobile,
non-road mobile sources and
biogenic/geogenic emissions. Point
sources are located individually
while county tallies are used for area
and mobile source category groups.
The inventory includes emissions of
S02, NOx, VOC, CO, PM10, elemental
carbon and organic carbon. Of these
pollutants, only CO is not a con-
tributor to the ambient fine particu-
late burden. The 1996 NET has been
completed for these pollutants and
also, a preliminary 1996 NET
inventory of PM25 and NH3 emis-
sions has been compiled for review
by the states. The figure is based in
part on information in this prelimi-
nary PM25 inventory and the
inventory will be incorporated into
the 1996 NET following State review
and refinements.
Figure 2-46 provides a link
between the sources in the NET
inventory and the composition
information shown in Figure 2-46.
The stacked bar graphs show the
relative magnitude of emissions S02,
NO , carbonaceous and crustal-
x'
related particles. S02 is emitted
mostly from the combustion of fossil
fuels in boilers operated by electric
utilities and industry. Less than 20
percent of S02 emissions nation-
wide are from industrial processes
and mobile sources. NO emissions
X
are more evenly divided between
stationary source and mobile source
fuel combustion and biogenic
sources are also about 10 percent of
NOx emissions. S02 and NOx also
form ammonium sulfate and nitrate
in the presence of ammonia under
certain atmospheric conditions.
Animal husbandry, mobile sources,
Figure 2-45. Summary of information from actual measurements of ambient PM2
Carbonaceous [^] Nitrate I I Crustal I I Sulfate I INot Chemically
Characterized b
South Coast Basin
(4 Site Avg ¦ 28 ug/m3)
Urban
©
Spokane
(11.0 ug/m3)
Rochester
(14.9 ug/m3)
Boston
(16.2 ug/m3)
San Joaquin valley
(4 Site Avg - 37 ug/m3)
W. Phoenix E. Tennessee (3 Cities)
(13.5 ug/m3) (Avg -16.7 ug/m3)
Washington, DC
(19.2 ug/m3)
Sierra Nevada
(4.5 ug/m3)
Nonurban
Baa anas
Boundary Waters
(5.1 ug/m3)
(4.5 ug/m3)
San Joaquin valley
(21.6ug/m3)
New England
(9.5 ug/m3)
Sonoran
4.3 ug/m3
Central Rockies
(3.1 ug/m3)
Appalachian & Mid-Atlantic
(11.35 ug/m3)
Mid-South
(12.1 ug/m3)
a. PM25 mass concentrations are based on at least one year of monitoring at each
location using a variety of non-federal reference methods. They should not be used to
determine compliance with the PM25 NAAQS. Urban pies are based on one site per
city or area unless otherwise noted. With exception of the Sierra Nevada and
Badlands, nonurban pies represent an average of two or more sites located in the
same region.
b. A white segment in a pie indicates that the sum of the constituents (as determined
by separate analyses) was less than the gravimetrically determined mass
concentration. This could be because study objectives did not require analysis of
certain constituents (e.g., no carbon or nitrate analyses for the Tennessee sites) or a
variety of technical reasons.
44 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Nitrogen Oxides
Ammonium sulfate particles are formed from emissions of gaseous S02
(and also SO3 and sulfuric acid aerosols) emitted mostly from utility and
industrial boilers and to a lesser degree from certain industrial
processes and mobile sources.
Ammonium nitrate particles are formed from emissions of gaseous NOx
emitted mostly from utility and industrial boilers but also from highway
and off highway mobile sources and to a lesser degree, biogenic and
miscellaneous combustion sources and certain industrial processes.
Ammonia
Carbonaceous
Particles
Ammonium sulfate and nitrate particles are formed from emissions of
SO2 and NOx reacting with gaseous ammonia. Emission sources are
animal husbandry, fertilizer manufacturing and application and to a
lesser degree from mobile sources, and other combustion and
industrial processes.
Carbonaceous particles are emitted directly and as condensed liquid
droplets from fuel combustion, burning of forests, rangelands and
fields; off highway and highway mobile sources (gas and diesel); and
certain industrial processes.
Crustal
Particles emitted directly from non industrial surface (e.g., paved and
unpaved road traffic, construction, agricultural operations, high wind
events) and some industrial processes.
Source category contributions to National emissions of PM2.5 (directly emitted crustal and elemental/
organic carbon-related particles and SC^and NOx, precursors to ammonium sulfate and nitrate.)
(Boilers / Res Heating)
Industrial Processes (Organic),
Highway Vehicles
Off Highway
Open / Biomass Burn
SO2
NOx
Fuel Combustion _
(Boilers / Res Heating)
Industrial Processes (Organic) —
H ig hway Veh icl es —
Off Highway —
Open / Biomass Burn —
Fugitive Dust
(Non Industrial)
Industrial Processes (Inorganic)
Carbonaceous Crustal
Particles
Note: Composition and source contributions vary among urban areas. Also, some
carbonaceous material is formed from organic gases reacting in the atmosphere. The
magnitude of these secondary organics is believed small, but more research is needed.
Figure 2-46. PM2 5 emission sources.
Sulfur Dioxide
industrial processes and fertilizer
application are sources of ammonia.
The main sources of carbonaceous
(combustion-related) particles are
about equally divided among fuel
combustion in boilers, biomass
combustion and mobile sources.
Key biomass sources are wildfires,
managed burning and residential
wood burning. Principal mobile
sources include both on and off road
diesels, gasoline engines and
aircraft, railroads and ships.
Industrial process emissions will
likely be important in some areas as
will miscellaneous combustion
sources. The main sources of
crustal particles are roads, construc-
tion, agriculture and high wind
events. Crustal materials are the
predominant component of PM10,
but Figure 2-46 shows that PM25 is
predominantly comprised of
secondary particles and directly
emitted carbonaceous particles.
The composition (and thus the
sources) of PM25 and PM10 are
markedly different because most of
the crustal material particles are
larger than 2.5 micrometers while
almost all of the secondary particles
and directly emitted carbonaceous
particles are smaller than 2.5
micrometers.
Used together, the figures can
give a qualitative feel for the
combined influence of specific
source types on ambient PM25
overall (e.g., fuel combustion in
boilers, organic and inorganic
industrial processes, highway and
off highway mobile sources, open
burning of waste/biomass and
fugitive dust). For example, Figure
2-46 shows that fuel combustion in
boilers contributes significantly to
both sulfate and carbonaceous mass.
Figure 2-45 shows that both sulfate
and carbonaceous particles are
found in abundance in PM25 in the
East and that carbonaceous particles
are also abundant in the West.
Thus, preliminary conclusions are
(1) that fuel combustion in boilers is
a significant contributor to PM25 in
the ambient air and (2) that fugitive
dust sources do not appear to play a
particularly important role in
ambient air samples of PM25.
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 45
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Notes on Data Sources for PM25
Composition and concentration data for all non-urban locations were obtained from the Interagency Monitoring of Pro-
tected Visual Environments (IMPROVE) except for the New England location which is based on combined non-urban data
from IMPROVE and the Northeast States for Coordinated Air Use Management (NESCAUM). Washington, D.C. data also
were obtained from IMPROVE and the Boston and Rochester data are based on NESCAUM. [References: a) IMPROVE, Co-
operative Center for Research in the Atmosphere, Colorado State University, Ft. Collins, CO, July 1996. b) Salmon, Lynn,
and Glen R. Cass, October, 1997, Progress Report to NESCAUM: Determination of Fine Particle Contraction and Chemical
Composition in the Northeastern United States, 1995, California Institute of Technology, Pasadena, CA 91125. Draft.] Note
that the NESCAUM data is still subject to minor revision. The South Coast information is adapted from Christoforou. [Ref-
erence: Christoforou, C.S., Lynn G. Salmon, Michael P. Hannigan, Paul A. Soloman and Glen R. Cass, Trends in Fine Particle
Concentration and Chemical Composition. Accepted for publication in Journal of Air and Waste Management Association,
Pittsburgh, PA.] Phoenix data is from the EPA's Particulate Matter (PM) Research Monitoring Network [Reference: The Na-
tional Environmental Research Laboratory/ Research Triangle Park PM Research Monitoring Network, U.S. EPA, Research
Triangle Park, NC 27711,1997.] with the exception of the nitrate estimates which were adapted from Desert Research Insti-
tute (DRI). [References: (a) PM10 and PM25 Variations in Time and Space, Desert Research Institute, Reno, NV, October 1995.
(b) Watson, John G. and Tom Moore, personal communications with T.G. Pace, December 1997.] The San Joaquin data are
from DRI. [Reference: PM10 and PM25 Variations in Time and Space, Desert Research Institute, Reno, NV, October 1995. ]
Spokane's composition and concentration data was obtained from Norris. [Reference: 7. Norris, Gary and Jane Koenig,
Preliminary Analysis of PM and Daily Emergency Room Visits for Asthma in Spokane, Washington, USA, Presented at In-
ternational Symposium on Health Effects of PM, Prague, Czech Republic, April 1997.] Eastern Tennessee data was obtained
from studies conducted in Knoxville and Chattanooga by the Tennessee Valley Authority and in Nashville by the Harvard
School of Public Health.89 [References: (a) Tanner, R. (Tennessee Valley Authority) Personal Communication with T.G. Pace,
January, 1998. (b) Bahadori, Tina and Helen Suh (Harvard School of Public Health) Personal Communication with T.G.
Pace, January, 1998]
Non-urban data are based on averages of several monitoring locations in the region. Urban data are based on only one
location in each area and may not represent the entire urban area. The exceptions to this are the South Coast and San
Joaquin Valley areas of California where multiple locations are averaged together. In the South Coast basin, Rubidoux re-
corded the highest average PM25 and nitrate concentrations. Additional information on the composition of PM25 within
these areas of California is discussed further in Christoforou and DRI. [References: a) Christoforou, C. S., Lynn G. Salmon,
Michael P. Hannigan, Paul A. Soloman and Glen R. Cass, Trends in Fine Particle Concentration and Chemical Composition.
Accepted for publication in Journal of Air and Waste Management Association, Pittsburgh, PA. and b) PM10 and PM25 Varia-
tions in Time and Space, Desert Research Institute, Reno, NV, October 1995.]
46 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Sulfur Dioxide
• Air Quality Concentrations
1988-97
39% decrease
1996-97
4% decrease
• Emissions
1988-97
12% decrease
1996-97
3% increase
Nature and Sources
SOz belongs to the family of SOx
gases. These gases are formed when
fuel containing sulfur (mainly coal
and oil) is burned, and during metal
smelting and other industrial pro-
cesses. The highest monitored con-
centrations of S02 are recorded in the
vicinity of large industrial facilities.
Health and Environmental Effects
High concentrations of S02 can
result in temporary breathing
impairment for asthmatic children
and adults who are active outdoors.
Short-term exposures of asthmatic
individuals to elevated S02 levels
while at moderate exertion may
result in reduced lung function that
may be accompanied by symptoms
such as wheezing, chest tightness,
or shortness of breath. Other effects
that have been associated with
longer-term exposures to high
concentrations of S02, in
conjunction with high levels of PM,
include respiratory illness,
alterations in the lungs' defenses,
and aggravation of existing
cardiovascular disease. The
subgroups of the population that
may be affected under these
conditions include individuals with
cardiovascular disease or chronic
lung disease, as well as children
and the elderly. Additionally, there
are a variety of environmental
Figure 2-47. Trend in annual mean S02 concentrations, 1988-1997.
Concentration, ppm
0.04{
0.03
-90th Percentile
^c-Mean
-Median
10th Percentile
486 Sites
NAAQS
0.02
0.01
0.001
88 89 90 91 92 93 94 95 96 97
concerns associated with high
concentrations of S02. Because S02,
along with NOx, is a major
precursor to acidic deposition (acid
rain), it contributes to the
acidification of soils, lakes and
streams and the associated adverse
impacts on ecosystems. (See
Chapter 7: Acid Deposition). S02
exposure to vegetation can increase
foliar injury, decrease plant growth
and yield, and decrease the number
and variety of plant species in a
given community. S02 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, S02
can accelerate the corrosion of
natural and man-made materials
(e.g., concrete and limestone) which
are used in buildings and
monuments, as well as paper,
leather, iron-containing metals and
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 ng/m3) is not to be exceeded
more than once per year. The long-
term standard specifies an annual
arithmetic mean not to exceed 0.030
ppm (80 ng/m3). The secondary
NAAQS (3-hour) of 0.50 ppm (1,300
Hg/ 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 1988
and 1997 as shown in Figure 2-47,
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 47
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
with the largest single-year reduction
(19 percent) occurring between 1994
and 1995.32 The trend has since lev-
eled off, declining only 4 percent
from 1996-1997. This same general
trend is seen in Figure 2-48 which
plots the ambient concentrations
grouped by urban, suburban, and
rural sites. It shows that the mean
concentrations at the urban and sub-
urban sites are consistently higher
than those at the rural sites. How-
ever, the 1994-1995 reduction in the
concentrations at non-rural sites does
narrow the gap between the trends.
The greater reduction 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 utili-
ties occurred.33
Emissions Trends
National SO2 emissions decreased 12
percent between 1988 and 1997, with
a sharp decline between 1994 and
1995, similar to the decline in the
ambient concentrations. Unlike the
air quality trend, the emissions trend
begins to climb again from 1995-
1997, as shown in Figure 2-49. 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 combus-
tion category in Figure 2-50. In par-
ticular, the coal-burning power plants
have consistently been the largest
contributor to SO2 emissions as docu-
mented in Table A-8 in Appendix A.
Figure 2-48. Annual mean S02 concentration by trend location, 1988-1997.
Concentration, ppm
0.012
0.01
0.008
0.006
0.004
0.002
Rural (127 sites) Suburban (202 sites) Urban (147 sites)
0
88 89 90 91 92 93 94 95 96 97
Figure 2-49. National total S02 emissions trend, 1988-1997.
Thousand Short Tons Per Year
30,000
~ Fuel Combustion H Industrial Processing
~ Transportation ~ Miscellaneous
25,000
20,000
15,000
10,000
5,000
88 89 90 91 92 93 94 95 96 97
48 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 2-5. Total S02 Emissions from Phase I units and Non-Phase I units, 1994-97 (thousand
short tons).
1994 1995 1996 1997 1994-95 199S-97
Phase I units 6,915 4,938 5,259 5,304 -1,977 +366
Non-Phase I units and
Other Units 7,974 7,142 7,373 7,778 -832 +636
All Electric Utility units 14,889 12,080 12,632 13,082 -2,809+1,002
Figure 2-50. S02 emissions by source category, 1997.
Miscellaneous 0.1%
Transportation 6.i
Industrial Processes
Fuel Combustion 84.7%
Figure 2-51. Long-term ambient S02 trend, 1978-1997.
Concentration, ppm
0.014
0.012
0.01
0.008
0.006
0.004
0.002
0
78 80 82 84 86 88 90 92 94 96
The Acid Rain Program
The national reductions from 1994-
1995 in emissions and ambient
concentrations of S02 are due
mainly to Phase I implementation
of the Acid Rain Program. Estab-
lished by EPA under Title IV of the
CAA, the Acid Rain Program's
principal goal is to achieve signifi-
cant reductions in S02 and NOx
emissions. Phase I compliance for
S02 began in 1995 and significantly
reduced emissions from the partici-
pating utilities.33 Table 2-5 shows
this reduction in terms of Phase I
and other units and Non-Phase I
and other units.34 The 1994-1995
decrease in total S02 emissions
from electric utilities is due largely
to the Phase I emissions reduction
which accounted for 70 percent
(1,977 thousand short tons) of the
total reduction (2,809 thousand
short tons) from electric utilites.
Since 1995, however, total S02
emissions from electric utilities
have increased. Again, Table 2-4
explains this increase in terms of
Phase I units and Non-Phase I
units. Most Phase I plants over-
complied in 1995 and were able to
use their banked emission allow-
ances in 1996 and 1997. As a result,
S02 emissions have increased
slightly at some Phase I sources
since the initial reduction in 1995.
However, Phase I units account for
only 37 percent of the total 1995 to
1997 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, which begins in 2000.
When fully implemented, total S02
emissions from electric utilities are
capped at 8.9 million tons per year.
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 49
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-52. Trend in S02 annual arithmetic mean concentration by EPA Region, 1988-1997.
•f 32%
J 44%
J 40%
f.46%
J 33%
#¦ 45%
^¦32%
f 34%
The National Trend
.0089
..0054
J 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.
For more information on the acid rain
program, visit http://www.epa.gov/
acidrain.
National 20-Year Trends
The progress in reducing ambient SO2
concentrations during the past 20
years is shown in Figure 2-51. While
there is a slight disconnect in the
trend line between 1987 and 1988 due
to the mix of trend sites in each 10-
year period, an overall downward
trend is evident. In addition to the
previously mentioned effects of the
Acid Rain Program, these steady
reductions over time were accom-
plished by installing flue-gas control
equipment at coal-fired generating
plants, reducing emissions from in-
dustrial processing facilities such as
smelters and sulfuric acid manufac-
turing plants, reducing the average
sulfur content of fuels burned, and
using cleaner fuels in residential and
commercial burners.
Regional Trends
The map of regional trends in Figure
2-52 shows that ambient SO2 concen-
trations are generally higher in the
northeastern United States. The ef-
fects of Phase I of the Acid Rain Pro-
gram are seen most vividly in the
northeast. In particular, concentra-
tions fell 21-25 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 north-
east as shown in Figure 2-53. This
figure also shows that ambient con-
centrations have increased slightly
between 1995 and 1997 in Regions III
and IV where many of the electric
utility units not yet affected by the
Acid Rain Program are located.
1997 Air Quality Status
The most recent year of ambient data
shows that only one area, Buchanan
County, Missouri, did not meet the
primary S02 short-term standard,
according to Figure 2-54. The high
ambient concentration levels were
due to emissions from the local
power plant, St. Joe Power and Light
Company.
50 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 2-53. Plants affected by Phase I of the Acid Rain Program.
Figure 2-54. Highest second maximum 24-hour S02 concentration by county, 1997.
Concentration (ppm) <.034 .035- 144 .145-.304
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 51
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
References and Notes
1. Cohen, J. And E. Iwamiya, Analyses
of Diurnal Patterns in Hourly and Eight-
Hourly Average Ambient Carbon Monox-
ide Concentrations, Technical Memoran-
dum prepared under EPA Contract No.
68-D7-0066 by Systems Applications
International, Inc., San Rafael, CA, July
1998.
2. Oxygenated Gasoline Implementation
Guidelines, EPA, Office of Mobile Sourc-
es, Washington, D.C., July 27,1992.
3. 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).
4. Interagency Assessment of Oxygenated
Fuels, National Science and Technology
Council, Executive Office of the Presi-
dent, Washington, D.C., June 1997.
5. G. Whitten, J. Cohen, and A. Kuklin,
Regression Modeling of Oxyfuel Effects on
Ambient CO Concentrations: Final Re-
port, SYSAPP-96/78, prepared for the
Renewable Fuels Association and Oxy-
genated Fuels Association by System
Applications International, Inc., San
Rafael, CA, January 1997.
6. Cook, J.R., P. Enns, and M.S. Sklar,
Regression Analysis of Ambient CO Data
from Oxyfuel and Nonoxyfuel Areas,
Paper No. 97-RP139.02, Air and Waste
Management Association 90th Annual
Meeting, Toronto, Ontario, June 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, N.C.,
September 1995.
9. J.H. Seinfeld and S. N. Pandis, At-
mospheric Chemistry and Physics:
From Air Pollution to Climate Change,
John Wiley & Sons, Inc., New York, NY,
1998.
10. "1997 Compliance Report," EPA-
430-R-98-012, U.S. Environmental
Protection Agency, Acid Rain Program,
Washington, D.C., August 1998.
The emission reduction analyses asso-
ciated with NOx compliance results in
this report focus on 263 of the 265
Phase I NOx units (representing 170
Table I units and 95 substitution units
whose owners chose to participate in
Phase I as part of an S02 compliance
strategy). EPA had determined, as of
July 1998, that these units had met the
required emission limitation; the two
other Phase I units were pending a
decision on their alternative emission
limitation petitions and determined to
be conditionally in compliance.
11. "Finding of Significant Contribu-
tion and Rulemaking for Certain States
in the Ozone Transport Assessment
Group Region for Purposes of Reduc-
ing Regional Transport of Ozone; Pro-
posed Rule," Federal Register, 62 FR
216, Washington, D.C., November 7,
1997.
12. "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 142, Washington, D.C.,
July 24, 1998.
13. "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.
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, 63 FR 39431, Washing-
ton, D.C., July 22,1998.
15. "National Ambient Air Quality
Standards for Ozone; Final Rule,"
Federal Register, 62 FR 38856, Washing-
ton, D.C., July 18,1997.
16. "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.
17. "Rethinking the Ozone Problem in
Urban and Regional Air Pollution,"
National Research Council, National
Academy Press, Washington, D.C.,
December 1991.
18. 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.
19. "Ambient Air Quality Surveillance:
Final Rule," Federal Register, 58 FR
8452, Washington, D.C., February 12,
1993.
20. "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.
21. "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.
22. "Requirements for Reformulated
Gasoline," Federal Register, 59 FR 7716,
Washington, D.C., February 16,1994.
23. Birth, T., "User's Guide to the PC
Version of the Biogenic Emissions
Inventory System (PC-BEIS2)," EPA-
600/R-95-091, U.S. Environmental
52 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Protection Agency, Research Triangle
Park, NC, 1995.
24. Geron, C., A. Guenther, and T.
Pierce, "An Improved Model for Esti-
mating Emissions of Volatile Organic
Compounds from Forests in the East-
ern United States," Journal of Geophysi-
cal Research, vol. 99, pp. 12773-12791,
1994.
25. National Air Pollutant Emission
Trends, 1900-1996, EPA-454/R-97-011,
U.S. Environmental Protection Agency,
Research Triangle Park, NC, 1997.
26. "Climate Variations Bulletin: Au-
gust 1997," Historical Climatology Series
4-7, Volume 9, Number 8, National
Climatic Data Center, NOAA,
Asheville, NC, September 1997.
27. "Finding of Significant Contribu-
tion and Rulemaking for Certain States
in the Ozone Transport Assessment
Group Region for Purposes of Reduc-
ing Regional Transport of Ozone; Pro-
posed Rule," Federal Register, 62 FR
60317, Washington, D.C., November 7,
1997.
28. "Supplemental Notice for the Find-
ing of Significant Contribution and
Rulemaking for Certain States in the
Ozone Transport Assessment Group
Region for Purposes of Reducing Re-
gional Transport of Ozone; Proposed
Rule," Federal Register, 63 FR 25902,
Washington, D.C., May 11,1998.
29. "Finding of Significant Contribu-
tion and Rulemaking for Certain States
in the Ozone Transport Assessment
Group Region for Purposes of Reduc-
ing Regional Transport of Ozone; Final
Rule," Federal Register, 63 FR 57355,
Washington, D.C., October 27,1998.
30. National Ambient Air Quality Stan-
dards for Particulate Matter: Final Rule,
July 18,1997. (62 FR 38652), http://
w w w. cpa.go v/ttn/oar p^rulcs.h tml.
31. National Air Pollutant Emissions
Trends Report, EPA-454/R-97-011, US
EPA, Research Triangle Park, NC
27711, December 1997.
32. The annual mean is used to show
trends in national S02 air quality be-
cause it is a more stable statistic than
the 24-hour statistic.
33. 1997 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.
34. The 1995, 1996, and 1997 data for
electric utility units in the acid rain
program were measured by continuous
emissions monitors or equivalent con-
tinuous monitoring methods and re-
ported to EPA's Acid Rain Division.
The 1994 data are based on fuel use
reported to DOE/Energy Information
Administration and AP-42 emissions
factors. "Phase I units" consist of the
400 units that were subject to Phase I
compliance during the first three years
(1995-1997) of the acid rain program.
These data were obtained from U.S.
Environmental Protection Agency,
Office of Air and Radiation, Office of
Atmospheric Programs, Acid Rain
Division, (Mail code: 6204J), Washing-
ton, D.C.
CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS 53
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
54 CHAPTER 2: CRITERIA POLLUTANTS - NATIONAL TRENDS
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CHAPTER 3
Criteria Pollutants -
Metropolitan Area Trends
http://www.epa.gov/oar/aqtrnd97/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 MS As and not all MS As 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-16). Table A-13 gives
the 1997 peak statistics for all MSAs,
providing the status of the most re-
cent year. Ten-year trends are shown
for the 251 MSAs having data that
meet the trends criteria explained in
Appendix B. Table A-14 lists these
MSAs and reports criteria pollutant
trends as "upward" or "downward,"
or "not significant." These categories
are based on a statistical test, known
as the Theil test, which is described
later in this chapter. The results of
these tests are displayed in Figures
3-1 through 3-9 as maps showing
upward, downward or non-significant
trends. Another way to assess trends
in MSAs is to examine Pollutant Stan-
dards Index (PSI) values.2,3 The PSI is
used to combine daily information on
one or more criteria pollutants into an
easily understood format, which can
then be presented to the public in a
timely manner. Tables A-15 and A-16
list the number of days with PSI values
greater than 100 (unhealthy for sensi-
tive groups) for the nation's 94 largest
metropolitan areas (population
greater than 500,000). Table A-15
lists PSI values based on all pollut-
ants, while Table A-16 lists PSI values
based on ozone alone. For the 10-
year period, the PSI calculated for
ozone is based on the revised stan-
dard discussed in Chapter 2. The
tables listing PSI data from previous
reports may not agree with the tables
in this report because of the new way
to calculate the PSI for ozone.
Not every MSA appears in these
tables because of the availability of
data or the size of the MSA. There are
MSAs with no ongoing monitoring
because they are not believed to have
pollution problems. The same is true
for certain combinations of MSAs and
pollutants. There are also MSAs with
so little information that the criteria for
trends analysis are not met (see Ap-
pendix B). Finally, there are MSAs
that do not meet the population crite-
ria for tables A-15 and A-16 and,
therefore, are not included.
Status: 1997
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
Aerometric Information Retrival
System (AIRS) database). Table A-
13 lists peak statistics for all criteria
pollutants measured in an MSA.
Since certain areas are not consid-
ered to have a problem with all crite-
ria pollutants, all criteria pollutants
are not measured in all MSAs and,
therefore, are designated as "ND"
(no data) for those pollutants. Ex-
amining Table A-13 shows that 129
areas had peak concentrations from
at least one criteria pollutant ex-
ceeding standard levels. The num-
ber of areas is dramatically
increased over the count from 1996
data (45 areas). The increase can be
attributed to the change from the
pre-existing ozone and particulate
matter (PM) National Ambient Air
Quality Standards (NAAQS) to the
CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS 55
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 3-1. Summary of MSA 10-Year Trend Analyses, by Pollutant
Total #
MSAs
# MSAs
Up
# MSAs
Down
# MSAs
with No
Significant
Change
CO
Second Max, 8-hour
142
0
102
40
Lead
Max Quarterly Mean
93
1
73
19
no2
Arithmetic Mean
92
4
51
37
Ozone
Second Daily Max, 1-hour
193
1
46
146
Ozone
Fourth Daily Max, 8-hour
193
4
32
157
PM10
99th Percentile, 24-hour
207
0
159
48
PM10
Weighted Annual Mean
207
4
78
125
so2
Arithmetic Mean
146
2
102
42
so2
Second Max, 24-hour
146
3
93
50
revised ozone and PM NAAQS and
levels of the revised ozone and PM
standards discussed in Chapter 2,
rather than changes in ambient
concentrations. These 129 areas
represent 53 percent of the U.S.
population. Similarly, there were 6
areas representing 8 percent of the
population that had peak statistics
that exceeded two or more stan-
dards. Only two areas, (Philadel-
phia, PA and St. Louis, MO)
representing 3 percent of the U.S.
population, had peak statistics from
three pollutants that exceeded the
respective standards. High values
for two pollutants, PM10 and lead,
are due to localized industrial
sources in both of these MS As.
There were no areas, however, that
violated four or more standards. In
fact, 1997 was the sixth year in a
row that there were no violations of
the nitrogen dioxide (NO2) stan-
dards in the United States.
Trends Analysis
Table A-14 displays air quality
trends for MSAs.4 The data in this
table are average statistics of pollut-
ant concentrations from the subset
of ambient monitoring sites that
meet the trends criteria explained in
Appendix B. A total of 251 MSAs
have at least one monitoring site
that meet these criteria. As stated
previously, not all pollutants are
measured in every MSA.
From 1988 to 1997, statistics
based on the NAAQS were calculated
for each site and pollutant with avail-
able data. Spatial averages were ob-
tained for each of the 251 MSAs by
averaging 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 monitor-
ing intensity for different MSAs, the
averages for every MSA and year pro-
vide a consistent value with which
to assess trends.
Since air pollution levels are
affected 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 significant).
Since the underlying pollutant distri-
butions do not meet the usual as-
sumptions required for common least
squares regression, the regression
analysis was based upon a nonpara-
metric method commonly referred 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 up-
ward 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 single extreme
values.
Table 3-1 summarizes the
trend analysis performed on the 251
MSAs. It shows that there were no
upward trends in carbon monoxide
(CO) and PM10 (annual mean) at any
of the MSAs over the past decade.
Of the 251 MSAs, 221 had down-
ward trends in at least one of the
criteria pollutants, and only 15 had
upward trends. A closer look at
these 15 MSAs reveals that most are
well below the NAAQS for the re-
spective pollutant, meaning that
their upward trends are not immedi-
ately in danger of violating the
NAAQS. The areas that were near
or exceeding a NAAQS all involved
8-hour ozone with a significant
upward trend. These results dem-
onstrate significant improvements
in urban air quality over the past
decade.
56 CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 3-1. CO Trends in Metropolitan Statistical Areas, 1988-1997.
4- Significant Downward Trend
1" Significant Upward Trend
° Trend Not Significant
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
Figure 3-2. Pb Trends in Metropolitan Statistical Areas, 1988-1997.
Significant Downward Trend
Significant Upward Trend
° Trend Not Significant
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS 57
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 3-3. N02 Trends in Metropolitan Statistical Areas, 1988-1997.
4- Significant Downward Trend i
1" Significant Upward Trend
° Trend Not Significant
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
Figure 3-4. Ozone Trends in Metropolitan Statistical Areas (Fourth Max 8-hour), 1988-1997.
-&¦ Significant Downward Trend }
"t Significant Upward Trend V^7
° Trend Not Significant ^
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
58 CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 3-5. Ozone Trends in Metropolitan Statistical Areas (Second Daily Max 1-hour), 1988-1997.
4- Significant Downward Trend
f Significant Upward Trend
° Trend Not Significant
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
Figure 3-6. PM10 Trends in Metropolitan Statistical Areas (Weighted Annual Mean), 1988-1997.
4- Significant Downward Trend
f Significant Upward Trend
° Trend Not Significant
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS 59
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figures 3-1 through 3-9 sum-
marize the results of the trends analy-
sis geographically. This gives another
general indicator of how air quality
varies from one region to another.
Figure 3-1 shows the geographic
distribution of trends for CO. The
figure shows that while most of the
nation is experiencing a downward
trend, there are small pockets where
the trend is non-significant (Southern
Pennsylvania to Kentucky and parts
of Texas, Oklahoma, and New
Mexico). Figure 3-2 shows that
trends for lead (Pb) are down for
almost all of the country. Figure 3-3
shows that trends for NOo are either
down or non-significant with a
small pocket of upward trends in
Texas. Figures 3-4 and 3-5 show the
ozone situation for MS As through-
out the country. Most MSAs have a
non-significant trend with down-
ward trends showing up in South-
ern California and some of the
Northeast corridor. Figure 3-5,
based on the 8-hour ozone standard,
shows more areas with 1997 data
above the level of the revised stan-
dard. Figures 3-6 and 3-7 show
trends for the annual and the re-
vised daily form of the PMio stan-
dards. Figure 3-6 shows the PMio
weighted annual mean has mostly
downward trends with the excep-
tion of areas in Pennsylvania and
the northern plains states and a few
other isolated MSAs. The daily form
of the standard (Figure 3-7) shows
non-significant trends from Penn-
sylvania in all directions except
southwest, and from the northern
plains south to all the plains states
and into Arkansas and Louisiana.
Figures 3-8 and 3-9 give a picture of
the annual and daily SO2 forms of
the standard. A busy area from
Illinois through New Jersey show
downward trends, while many of
these MSAs have non-significant
trends for the daily form of the SOo
standard.
The Pollutant Standards Index
PSI values are derived from pollut-
ant concentrations. They are re-
ported daily in all urban areas of the
United States with populations
exceeding 200,000. The PSI is re-
ported as a value between zero and
500 or a descriptive word (e.g., "un-
healthy") and is featured on local
television or radio news programs
and in newspapers.
Figure 3-7. PM10 Trends in Metropolitan Statistical Areas (99th Percentile), 1988-1997.
4- Significant Downward Trend
Significant Upward Trend
0 Trend Not Significant
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
60 CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 3-8. S02Trends in Metropolitan Statistical Areas (Arithmetic Mean), 1988-1997.
4- Significant Downward Trend
H" Significant Upward Trend
Figure 3-9. S02Trends in Metropolitan Statistical Areas (Second Max 24-Hour), 1988-1997.
° Trend Not Significant
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
Significant Downward Trend
Significant Upward Trend
Trend Not Significant "**
Green denotes that the 1997 concentration is below the NAAQS
Red denotes that the 1997 concentration is above the NAAQS
CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS 61
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Based on their short-term
NAAQS, Federal Episode Criteria,8
and Significant Harm Levels,9 the
PSI is computed for PMio, SO2, CO,
O3, and NO2. Lead is the only crite-
ria 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 PSI is a tool used to
communicate pollution concerns to
a wide audience, there are also col-
ors linked to the general descriptors
of air quality. The five PSI color cat-
egories and their respective health
effects descriptors are listed in Table
3-2.
The PSI 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, concentra-
tions are converted into an index
value between zero and 500. The
pollutant with the highest index
value is reported as the PSI for that
day. Therefore, the PSI does not take
into account the possible adverse
effects associated with combina-
tions of pollutants (i.e., syner-
gism).2,3
A PSI value of 100 corresponds
to the standard established under
the Clean Air Act (CAA). A PSI value
greater than 100 indicates that at least
one criteria pollutant (with the excep-
tion of NO2) exceeded the level of the
NAAQS, therefore designating air
quality to be in the unhealthful range
on that day. Relatively high PSI values
activate public health warnings.
For example, a PSI of 200 initiates a
First Stage Alert at which time sensi-
tive populations (e.g., the elderly
and persons with respiratory ill-
nesses) are advised to remain in-
doors and reduce physical activity.
A PSI of 300 initiates a Second Stage
Alert at which time the general pub-
lic is advised to avoid outdoor activ-
ity.
EPA is revising the PSI to reflect
the revised ozone and PM NAAQS,
which will incorporate the latest
health effects information used to
revise the standards. The analysis
presented here uses a suggested revi-
sion for ozone that states were encour-
aged to use during the Summer of
1998. The PSI used for this analysis
INDEX
VALUE
AIR
QUALITY
LEVEL
POLLUTANT LEVELS
PM-10
W
SO,
w
CO
(8-hour)
o3
(1-hour)
ppnn
NO,
(1-hour)
HEALTH
EFFECT
DESCRIPTOR
PSI
COLORS
500
400
300
200
100
50
SIGNIFICANT
~ HARM —
EMERGENCY
¦ WARNING -
600
- 500 -
420
NAAQS
60% OF
NAAQS
350
150
50
2,620
2,100
¦ 1,600
800
365
80"
50
40
30
15
4.5
¦ 0.6 -
0.5
¦ 0.4 -
¦ 0.2 -
0.12
0.06
- 2.0
1.6
1.2
0.6
HAZARDOUS
VERY
UNHEALTHFUL
UNHEALTHFUL
MODERATE
GOOD
RED
ORANGE
YELLOW
GREEN
BLUE
8 No index values reported at concentration levels below those specified by "Alert Level" criteria.
b Annual primary NAAQS.
Table 3-2. Pollutant Standards Index Nellies with Pollutant Concentration,
Health Descriptors, and PSI Colors.
62 CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 3-10. Number of days with PSI values > 100, as a percentage of 1988 value.
Southern California All Others
88 89 90 91 92 93 94 95 96 97
Percent of 1988 Value
120
100
80
60
40
20
0
incorporates the level (0.08 ppm)
and form (max 8-hour average) of
the revised ozone standard for all 10
years. For this reason, Tables A-15
and A-16 may not agree with PSI
tables in earlier reports for the same
year.
Summary of PSI Analyses
Of the five criteria pollutants used to
calculate the PSI, CO, 03, PM10, and
S02 generally contribute to the PSI
value. Nitrogen dioxide is rarely the
highest pollutant measured because
it does not have a short-term
NAAQS and can only be included
when concentrations exceed one of
the Federal Episode Criteria or Sig-
nificant Harm Levels. Ten-year PSI
trends are based on daily maximum
pollutant concentrations from the
subset of ambient monitoring sites
that meet the trends criteria in Ap-
pendix B.
Since a PSI value greater than 100
indicates that the level of the NAAQS
for at least one criteria pollutant has
been exceeded on a given day, the
number of days with PSI values
greater than 100 provides an indicator
of air quality in urban areas. Figure 3-
10 shows the trend in the number of
days with PSI values greater than
100 summed across the nation's 94
largest metropolitan areas as a per-
centage of the 1988 value. Because
of their magnitude, PSI totals for Los
Angeles, CA, Riverside, CA, Bakers-
field, CA, and San Diego, CA are
shown separately as Southern Califor-
nia. Plotting these values as a per-
centage of 1988 values allows two
trends of different magnitudes to be
compared on the same graph. The
long-term air quality improvement in
urban areas is evident in this figure.
Between 1988 and 1997, the total
number of days with PSI values
greater than 100 decreased 56 percent
in Southern California and 66 per-
cent in the remaining major cities
across the United States. While five
criteria pollutants can contribute to
the PSI, the index is driven mostly
by ozone. The unusual ozone year,
1988, can be seen in this figure by
the large decrease between 1988 and
1989 for all the areas but Southern
California. Southern California was
less affected by the unusual meteo-
rology experienced that year in most
of the nation (see Chapter 2). In fact,
Figure 3-10 shows how much year-
to-year meteorology affects air pollu-
tion levels, since Southern
California has less year-to-year vari-
ability in meteorology and a
smoother trend.
PSI 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 better the
estimate of the PSI for a given day.
Ozone accounts for the majority of
days with PSI values above 100, but is
collected at only a small number of
sites in each area. Table A-16 shows
the number of days with PSI values
greater than 100 that are attributed to
ozone alone. Comparing Table A-15
and A-16, the number of days with a
PSI above 100 are increasingly due to
ozone. In fact, the percentage of days
with a PSI above 100 due to ozone
have increased from 92 percent in
1988, to 97 percent in 1997. The
increase is even more dramatic when
the unusual meteorology experienced
in 1988 is recognized (the 1989 per-
centage was much lower, 82 percent).
This increase reveals that ozone in-
creasingly accounts for those days
above the 100 level and reflects the
success in achieving lower CO and
PMio concentrations. However, the
CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS 63
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
typical one-in-six day sampling
schedule for most PMio sites limits
the number of days that PMio can
factor into the PSI determination.
The PSI currently is undergoing
revision to reflect the changes in the
ozone and PM NAAQS. These revi-
sions will be proposed in the Spring of
1998 and should be finalized by the
end of 1998. Concurrently, the Fed-
eral Episode Criteria and Significant
Harm Levels for ozone and PM are
being revised to reflect the health
effects data that motivated the revi-
sions to the ozone and PM NAAQS.
References and Notes
1. Statistical Abstracts of the United
States, 1997, 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 sum-
marized in the report for comparison
purposes, the intent of publishing Tables
A-14 through A-16 is to present infor-
mation 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-SimonsandD. Mintz, "As-
sessing Environmental Trends with
Nonparametric Regression in the SAS
Data Step," American Statistical Associ-
ation 1995 Winter Conference, Raleigh,
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, Non-
parametric 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.
64 CHAPTER 3: CRITERIA POLLUTANTS - METROPOLITAN AREA TRENDS
-------
CHAPTER 4
Criteria Pollutants -
Nonattainment Areas
http://www.epa.gov/oar/aqtrnd97/chapter4.pdf
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 it may be subject to the
formal rule-making process which
designates it as nonattainment. The
Clean Air Act Amendments (CAAA)
further classify ozone, carbon monox-
ide, and some particulate matter non-
attainment areas based on the
magnitude of an area's problem.
Nonattainment classifications may be
used to specify what air pollution
reduction measures an area must
adopt and when the area must
reach attainment. The technical
details underlying these classifica-
tions 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 1998.
0 Eagle River
< 0 Juneau
¦ Anchorage ¦ Fairbanks
North Star
GUAM
Plant
n Power Plant
0 piti Power
0 Tanguisso
O Guaynabo j
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.
Nonattainment designations based on the revised 8-hour ozone standard will not be
designated until 2000.
**PM10 nonattainment areas on map are based on the pre-existing PM10 standards.
Nonattainment designations based on the revised PM10 standards have not yet been
made.
¦
CO
•
Lead
¦
Ozone"
0
PM10**
0
S02
CHAPTER 4: CRITERIA POLLUTANTS - NONATTAINMENT AREAS 65
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 4-2. Classified ozone nonattainment areas where 1-hour standard still applies, September 1998.
Classifications
¦ Extreme (LA) & Severe Serious ^ Moderate
Note: San Francisco is Classified Other / Sec 185A & Incomplete Data Areas Not Included
Marginal
Figure 4-1 shows the location
of the nonattainment areas for each
criteria pollutant as of September
1998. Figure 4-2 identifies the ozone
nonattainment areas by degree of
severity. A summary of nonattainment
areas can be found in Table A-17 in
Appendix A. This condensed list also
is located on the Internet at http://
www.epa.gov/airs/nonattn.html
and is updated as areas are redesig-
nated. Note that Section 185a areas
(formerly known as "transitional ar-
eas") and incomplete areas are ex-
cluded from the counts in Table A-17.
For information on these areas includ-
ing Section 185a and incomplete
areas see the EPA Green Book site
located at http:^www.epa.gov/oar/
oaqps/greenbk.
As of September 1998, there were a
total of 130 nonattainment areas on
the condensed nonattainment list.
The areas on the condensed list are
displayed alphabetically by state.
Table 4-1. Areas Redesignated Between September 1997 and September 1998.
CO
NO,
•
Chico, CA
•
Los Angeles-South Coast Air
•
Fresno, CA
Basin, CA
•
Lake Tahoe South Shore, CA
Ozone
•
Modesto, CA
.
Evansville, IN
•
Portland, OR
.
Richmond, VA
•
Stockton, CA
•
San Francisco Bay Area, CA
•
Sacramento, CA
(redesignated to nonattainment)
•
San Francisco-Oakland-San Jose, CA
PM10
• Granite City, IL
•
San Diego, CA
Pb
•
Vermillion, IN
•
The number of lead nonattainment
so2
• Benton Co.. TN
areas remained the same since
September 1997.
•
Humphreys Co., TN
Polk Co., TN
Muscatine Co., IA
Table 4-2. Ozone Revocations of Nonattainment Areas Only
•
Albany-Schenectady-Troy, NY
•
Lewiston-Auburn, ME
•
Allentown-Bethlehem-Easton, PA-NJ
•
Manchester, NH
•
Altoona, PA
•
Poughkeepsie, NY
•
Atlantic City, NJ
•
Reno, NV
•
Buffalo-Niagra Falls, NY
•
Scranton-Wilkes-Barre, PA
•
Erie, PA
•
Smyth Co. (White Top Mtn.), VA
•
Essex Co., (Whiteface Mtn.), NY
•
Sussex Co., DE
•
Harrisburg-Lebanon-Carlisle, PA
•
York, PA
•
Jefferson Co., NY
•
Youngstown-Warren-Sharon, OH-PA*
•
Johnstown, PA
*
Youngstown was redesignated
•
Knox Co. and Lincoln Co., ME
April 4, 1996.
66 CHAPTER 4: CRITERIA POLLUTANTS - NONATTAINMENT AREAS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 4-3. Nonattainment Status
There are approximately 113 million
people living in areas currently
designated as nonattainment.
Areas redesignated between
September 1997 and September
1998 are listed in Table 4-1, by pollut-
ant. All redesignations were to attain-
ment except for the San Francisco
Bay Area which was redesignated to
nonattainment for ozone. Subsequent
to the 1997 O3 National Ambient Air
Quality Standards (NAAQS) revision,
EPA revoked the 1-hour O3 NAAQS in
most U.S. counties.1,2 Nonattainment
areas that had the 1-hour ozone stan-
dard revoked are listed in Table 4-2.
The present status of nonattainment
areas compared to the status after
nonattainment designations resulting
from the CAAA is shown in Table 4-3.
Ozone nonattainment areas for the
new 8-hour standard will not be desig-
nated until the year 2000.3
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, D.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. "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.
Pollutant
1991
1998
1998
#
areas
# areas
Population
(in 1,000s)
CO
42
20
34,047
Pb
12
10
1,375
no2
1
0
0
03
100
38
99,824
PM10
70
77
29,890
so2
51
34
4,695
CHAPTER 4: CRITERIA POLLUTANTS - NONATTAINMENT AREAS 67
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
68 CHAPTER 4: CRITERIA POLLUTANTS - NONATTAINMENT AREAS
-------
5
Air Toxics
http://www.epa.gov/oar/aqtrnd97/chapter5.pdf
Background
Hazardous air pollutants (HAPs),
commonly referred to as air toxics
or toxic air pollutants, are pollut-
ants known to cause or suspected
of causing cancer or other serious
human health effects or ecosystem
damage. Section 112 of the CAA
now lists 188 pollutants or chemical
groups as hazardous air pollutants
and targets sources emitting them
for regulation.1 Examples of air
toxics include heavy metals like
mercury and chromium; organic
chemicals like benzene, 1,3-butadi-
ene, perchloroethylene (PERC),
dioxins, and polycyclic organic
matter (POM).
HAPs are emitted from
literally thousands of sources
including: large stationary indus-
trial 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,
exposure to mixtures of pollutants
found in urban settings, or expo-
sure to pollutants emitted from
distant sources that are transported
through the atmosphere over
regional, national or even global
airsheds. Exposures of concern to
HAPs can be either short-term or
long-term in nature. In addition to
breathing air contaminated with air
toxics, people can also be exposed
to some HAPs through other
pathways such as through the
ingestion of contaminated food
from waters polluted from the
deposition of HAPs. Some HAPs
can bioaccumulate in body tissues.
When a predator feeds on contami-
nated prey, concentrations of these
bioaccumulative HAPs can build up
in the predator's tissues, magnify-
ing the toxic burden. Presently,
over 2,299 U.S. water bodies are
under fish consumption advisories
(for particular species of fish),
representing approximately 16.5
percent of the nation's total lake
acreage, and 8.2 percent of the
nation's river miles.2
Health and Environmental Effects
Compared to information for the
criteria pollutants described in
previous chapters, less information
is available concerning potential
health and environmental effects of
the HAPs. Most of the information
on potential health effects of these
pollutants is derived from experi-
mental animal data. The different
health effects which may be caused
by HAPs include cancer, neurologi-
cal, cardiovascular, and respiratory
effects, effects on the liver, kidney,
immune system and reproductive
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 expo-
sure circumstances. In some rare
cases, effects can be seen immedi-
ately. 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 from the
release of methyl isocyanate into
the atmosphere. In other cases, the
resulting effects (e.g. liver damage
or cancer) are associated with long-
term exposures and may not appear
until years after exposure. About
half of the HAPs have been classi-
fied by EPA as "known", "prob-
able" or "possible" human
carcinogens. Known human
carcinogens have been demon-
strated to cause cancer in humans.
Examples of these include benzene,
which has been shown to cause
leukemia in workers exposed over
several years to certain amounts in
their workplace air, and arsenic,
which has been associated with
lung cancer in workers at metal
smelters. Probable and possible
CHAPTER 5: AIR TOXICS
69
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
human carcinogens include chemi-
cals that we are less certain cause
cancer in people, yet for which
laboratory animal testing indicates
carcinogenic effects.
Some HAPs pose particular
hazards to people of a certain age or
stage in life (e.g. as a young child,
adolescent, adult, or elderly per-
son). Available data indicate that
about a third of HAPs are develop-
mental or reproductive toxicants
(e.g. mercury). 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 associated 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 contami-
nated food (e.g. fish). Apart from
the laboratory testing results on
animal species that make up a large
portion of the human 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 air toxics on
non-human species.
One of the more documented
ecological concerns associated with
toxic air pollutants is the potential
for some HAPs to damage aquatic
ecosystems. For example, a
number of studies suggest that
deposited air toxics contribute to
deleterious effects such as repro-
ductive failures, developmental
disorders, disease, and premature
death in fish and wildlife species
native to the Great Lakes.Deposited
air pollutants can be significant
contributors to overall pollutant
loadings entering water bodies
(especially for persistent chemicals
which continue to move among air,
water, and sediments). For the
Great Lakes, international programs
have examined the importance of
deposition of air toxics, relative to
other loadings such as direct
discharge. While data are pres-
ently insufficient for many quanti-
tative estimates comparing air
deposition and other loading
pathways, 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
particular concern in aquatic
ecosystems, as toxics levels can
magnify up the food chain resulting
in exposures greater than those
expected based solely on the levels
in water or air. For example, the
Florida panther, an endangered
species which inhabits the Ever-
glades, has experienced adverse
effects because of the high levels of
mercury that have accumulated in
the panther's tissues from eating
fish contaminated with mercury.
Such "bioaccumulation" and
"biomagnification" (where the
levels of a toxic substance increase
as you go higher in the food chain)
are also seen in breeding loons in
New England, a bird which feeds
on fish in waters contaminated by
airborne mercury. Studies are
showing that an estimated 30 per
cent of the breeding loons have
mercury levels that put them at risk
of behavioral, reproductive and
other effects.
Air Toxics Control Program
The Regulatory Response
In 1990, Congress amended Section
112 of the CAA by adding a new
approach to the regulation of HAPs.
This new approach is divided into
two phases. The first requires the
development of technology-based
emissions 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 first phase is comprised of
the technology-based standards,
known as MACT (Maximum
Achievable Control Technology)
and GACT (Generally Achievable
Control Technology) regulations,
under Sections 112(d). All large, or
major, sources of the 188 HAPs
must be addressed by such regula-
tions, as well as the smaller, area,
sources found to carry significant
risk or identified as important
under the Specific Pollutants
Strategy [Section 112(c)(6)] or the
urban program [Sections 112(c)(3)
and 112 (k)]. Some combustion
sources, such as municipal waste
combustors, are regulated under
equivalent requirements in Section
129. The purpose of this technol-
ogy-based approach is to use
70
CHAPTER 5: AIR TOXICS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 5-1. National total HAP emissions by source type, based on 1993 NTI.
Area Sources 18.0%
Mobile Sources 21.0%
Point Sources 61.0%
Figure 5-2. Source category contributions for selected states, based on 1993 NTI.
Percent
100
lllll
Alabama Indiana Louisiana Texas New York California Florida Arizona Hawaii Idaho
~ % Mobile Emissions
~ % Area Emissions
I % Point Emissions
available control technologies or
changes in work practices to get
emission reductions for as many of
the listed HAPs as possible. Al-
though there is no health test in this
phase, it is intended that effective
MACT standards will reduce a
majority of the HAP emissions and,
with it, potential risks from regu-
lated sources.
After application of the
technology-based standards comes
Phase Two, which consists of
strategies and programs for evalu-
ating remaining risks and ensuring
that the overall program has
achieved a sufficient reduction in
risks to public health and the
environment. This phase will be
implemented primarily through the
integrated urban air toxics strategy,
which will evaluate risks in urban
areas from the mix of source types
present, and the residual risk
program for MACT-controlled
sources (Section 112(f)). The
integrated urban strategy will
identify at least 30 HAPs which
have the greatest health risk in
urban areas, and assure that area
sources accounting for 90% of the
total emissions of those urban
HAPs are subject to MACT or
GACT regulations. In addition, the
strategy will target long-term
actions to substantially reduce risks
from urban air toxics from all
sources, to include a 75 percent
reduction in cancer risk from major
and area sources.
The second phase will also use
information generated through the
special studies required in the
Clean Air Act —the Great Waters
program [Section 112(m)], and the
Mercury and Utility Studies [Sec-
CHAPTER 5: AIR TOXICS
71
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
tion 112(n)]. The Great Waters
program contains an ongoing
examination of atmospheric deposi-
tion of air toxics to aquatic ecosys-
tems, and the effects of those toxics
when concentrated 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 numerous
toxics from electric utilities.
The components of this two
phase approach are described in
more detail later in this chapter.
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
examine problems on other scales
in order to address specific con-
cerns. The Act also provides
mechanisms for increasing partner-
ships among EPA, States and local
programs in order to address
problems specific to these regional
and local environments. As we
move toward the 21st century,
EPA's air toxics program is begin-
ning to progress from the more
technologically-based approach for
regulating toxics to the 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 ecosystem exposure to HAPs.
The development of an "informa-
tion infrastructure" to inform the
risk-based decisions has been a
priority for the EPA over the last
few years. The next part of this
chapter summarizes the resulting
activities and data from major
Figure 5-3. HAP Emissions by state, based on 1993 NTI.
I I HAP Emissions greater than 167,000 tons/yr
I I HAP Emisions between 77,000 - 167,000 tons/yr
I I HAP Emissions less than 77,000 tons/yr
Figure 5-4. State Data Summary for 1996 NTI.
I I States that submitted 1996 HAP inventory data.
72
CHAPTER 5: AIR TOXICS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 5-1. E mission Reductions from Full Implementation of MACT Standards
Compliance
Date
11/15/93
MACT
Source
Category
HAPs
Emitted
Total Baseline
Pre-MACT
Emissions'3
Emissions
Reductionb
Total
Post-MACT
Emissions'3
Coke Ovens:
Charging, Top side,
and Door leaks3
Benzene
Coke oven gases
Poly cyclic Organic Matter
1,760 tpy
80% = 1,408 tpy
352 tpy
9/23/96
Perchloroethylene
Dry Cleaning Facilities
Perchloroethylene
95,700 tpy
56% = 53,592 tpy
42,108 tpy
3/8/96
Industrial Process
Cooling Towers
Chromium & compounds
25 tpy
>99%
0
12/15/96 (w/o new
control device),
12/15/97 (w/ new
control device)
Magnetic Tape
Manufacturing
Methyl ethyl ketone
Methyl isobutyl ketone
Toluene
4,470 tpy
51% = 2,300 tpy
2,170 tpy
1/25/96
(decorative)
1/25/97 (hard &
anodizing)
Chrome Electroplating:
- Decorative
- Hard
-Anodizing
Chromium & compounds
11.5
160
3.9 = 175.4 tpy
99% = 173 tpy
2 tpy
4/22/97
Hazardous Organic
NESHAP (HON)
Total unspeciated HAPs
573,000 tpy
90%= 515,700 tpy
57,300 tpy
112/2/97
Halogenated Solvent
Cleaning
Methyl chloroform Tetrachloroethylene
Methylene chloride Trichloroethylene
142,000 tpy
60% =85,200 tpy
56,800 tpy
12/15/97
Gasoline Distribution
Benzene Methyl tert-butyl ether
Cumene Polycyclic Organic Matter
Ethyl benzene Toluene
Ethylene dichloride 2,2,4-Trimethylpentane
Hexane Xylenes (o,m,p)
Lead & compounds
44,200 tpy
5% = 2,210 tpy
41,990tpy
12/16/97
Shipbuilding and Ship
Repair Facilities
Acrylonitrile Methyl chloroform
Chlorine Methyl ethyl ketone
Chromium & compounds Methyl isobutyl ketone
Diethanolamine Methylene chloride
Ethylbenzene Nickel & compounds
Ethylene dichloride Polycyclic Organic Matter
Ethylene glycol Toluene
Glycol ethers Trichloroethylene
Lead & compounds Xylenes (o,m,p)
Manganese & compounds
7,890 tpy
24% = 1,894 tpy
5,996 tpy
12/23/97
Secondary Lead
Smelting
Acetaldehyde Ethylbenzene
Acetophenone Formaldehyde
Acrolein Hexane
Acrylonitrile Lead & compounds
Antimony & compounds Manganese & compounds
Arsenic & compounds Mercury & compounds
Benzene Methyl bromide
Biphenyl Methyl chloride
Bis (2-ethylhexyl)phthalate Methyl ethyl ketone
1,3-Butadiene Methyl iodide
Cadmium & compounds Methylene chloride
Carbon disulfide Nickel & compounds
Chlorobenzene Phenol
Chloroform Polycyclic Organic Matter
Chromium & compounds Propionaldehyde
Cumene Styrene
Dibutyl phthalate 1,1,2,2-Tetrachloroethane
1,3-Dichloropropene Toluene
Dioxins/Furans Trichloroethylene
Ethyl carbamate Xylenes(o,m,p)
2,030 tpy
72% = 1,421 tpy
609tpy
a Due to the various criteria for implementation dates for coke ovens, the date shown here is the Effective Date.
b tons per year is abbreviated as tpy.
CHAPTER 5: AIR TOXICS
73
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 5-2. Comparison of 1993 to 1996 Emission Reductions for Mobile On-Road
Gasoline Vehicles
1993 Total HAP
Emissions
(tons per year)
1996 Total HAP
Emissions
(tons per year)
Emissions
Reduction
(tons per year)
1,571,000
1,313,000
258,000 = 16%
Table 5-3. HAPs Emitted From On-Road Gasoline Vehicles
Acetaldehyde
Manganese and compounds
Acrolein
Mercury and compounds
Arsenic and compounds
Methyl tert-butyl ether3
Benzene
Nickel and compounds
1,3-Butadiene
Polycyclic Organic Matter (defined as
Chromium and compounds
16-PAH)
Dioxins/Furans (defined as TEQ)
Propionaldehyde
Ethylbenzene
Styrene
Formaldehyde
Toluene
n-Hexane
Xylenes (ortho-,meta-,para-)
Lead and compounds
'not available for the 1993 inventory year
sectors of that infrastructure —
emissions inventories, ambient
monitoring, and modeling. Data
from these three areas are already
assisting the EPA in more quantita-
tively characterizing the air toxics
problems. As the information
continues to improve, it will
provide the base for air toxics
decisions in the future.
Air Toxics Characterization
Emissions Data ¦ National Toxics
Inventory
In 1993, there were approximately
8.1 million tons of air toxics re-
leased to the air according to EPA's
National Toxics Inventory (NTI).
These emissions came from all
types of manmade sources, includ-
ing large industrial sources, small
stationary sources, and mobile
sources. As shown in Figure 5-1,
1993 NTI estimates reveal that
point, or major, sources (sources of
hazardous air pollutants (HAPs)
emitting more than 10 tons per year
of an individual HAP or 25 tons per
year of aggregate emissions of
HAPs) account for approximately
61 percent of the total HAP emis-
sions, nationally, while area sources
(smaller stationary sources) contrib-
ute approximately 18 percent, and
mobile sources contribute 21
percent. Since these estimates vary
from State to State, Figure 5-2
illustrates the range in percent
contributions of point, area, and
mobile source emissions for se-
lected states. Figure 5-2 shows that
point source contributions ranged
from 81 percent (Alabama) to 16
percent (Hawaii), area source
contributions ranged from 48
percent (Idaho) to 9 percent (Ala-
bama), and mobile source contribu-
tions ranged from 55 percent
(Hawaii) to 10 percent (Alabama).
Figure 5-3 presents the geographic
distribution of 1993 emissions of
HAPs by mass at the State level.
While this figure shows total
emissions of HAPs for each State, it
does not imply relative health risk
from exposure to HAPs. The
categorization of pollutant
emissions as high, medium, and
low only provides a rough sense of
the geographic distribution of
emissions. In viewing these figures
it is important to note that some
states may show relatively high
emissions totals as a result of very
large emissions from a few facili-
ties. Likewise, relatively large
emissions totals may also result
from numerous small point sources.
The EPA periodically updates
the NTI and is currently compiling
the 1996 NTI. The 1993 NTI in-
cludes emissions information for
166 of the 188 HAPs from 958 point-
, area-, and mobile-source catego-
ries. Emissions data from the Toxic
Release Inventory (TRI) were used
as the foundation of the 1993 NTI.
However, the TRI's lack of emission
estimates from mobile and area
sources severely limit its utility as a
comprehensive air toxics emissions
database.4 Analysis of the 1993 NTI
suggests that the TRI data alone
represent less than 10 percent
(760,000 tons/year) of the total NTI
emissions. The NTI, therefore,
74 CHAPTER 5: AIR TOXICS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 5-4. 33 Draft Urban HAPsa
HAP Name
CAS Number
Acetaldehyde
75070
Acrolein
107028
Acrylonitrile
107131
Arsenic and compounds
Benzene
71432
Bis(2-ethylhexyl)phthalate
117817
1,3-Butadiene
106990
Cadmium and compounds
Carbon tetrachloride
56235
Chloroform
67663
Chromium and compounds
1,4-Dichlorobenzene
106467
1,3-Dichloropropene
542756
Dioxins/Furans (defined asTEQ)
Ethylene dibromide (dibromoethane)
106934
Ethylene dichloride (1,2-dichloroethane)
107062
Ethylene oxide
75218
Formaldehyde
50000
Hydrazine
302012
Lead and compounds
Manganese and compounds
Mercury and compounds
Methylene chloride (dichloromethane)
75092
Methylene diphenyl diisocyanate (MDI)
101688
Nickel and compounds
Polycyclic organic matter (defined as 16-PAH)
Propylene dichloride (1,2-dichloropropane)
78875
Tetrachloroethylene (perchloroethylene)
127184
Trichloroethylene
79016
Vinyl chloride
75014
Coke oven emissions
Methyl chloride
Quinoline
a The first 30 HAPs in this list have significant contributions from area source categories, and
thus, required listing under sections 112(c)(3) and 112(k). The last 3 HAPs, coke oven emis-
sions, methyl chloride, and quinoline are predominantly emitted by major sources.
Figure 5-5. National emissions of 30 draft urban area source HAPs, 1990.
Urban 66.0%
Area 40.0% / Point 20.0%
Rural 34.0% Mobile 40.0%
sought other sources to fill in the
gaps. Data from EPA studies, such
as the Mercury Study,5 inventories
for Clean Air Act sections 112c(6)
and 112(k), and data collected
during development of Maximum
Achievable Control Technology
(MACT) Standards under section
112(d), supplement the TRI data in
the NTI.
The 1993 and 1996 NTIs also
incorporate data from State and
local HAP inventories. The 1996
NTI currently includes 38 HAP
inventory data from State and local
agencies (representing 34 States).
Figure 5-4 shows the States that
have submitted 1996 HAP inven-
tory to EPA. Thus, the State and
local HAP inventories will form the
new foundation of the 1996 NTI.
One other important distinction
between the 1993 and 1996 NTI is
that 1993 data are allocated at the
county level, whereas, the 1996 NTI
data will be allocated at the facility
level for point (major) sources. This
allows for greater spatial detail in
the 1996 NTI. The complete 1996
NTI is targetted for completion in
the Fall of 1999.
As a result of the implementa-
tion of MACT standards, point
source emissions are estimated to
have decreased by over 660,000 tons
from 1993 through 1997. Table 5-1
presents a summary of estimated
emission reductions from the full
implementation of MACT stan-
dards with compliance dates
through 1997.
Table 5-2 compares 1993 and
1996 mobile on-road source emis-
sions. Mobile on-road emissions
decreased by 258,000 tons over this
time period, primarily as a result of
CHAPTER 5: AIR TOXICS
75
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 5-6. National urban and rural emissions of 30 draft urban area source HAPS,
1990.
Rural Areas
Urban Areas
Mobile 45.0%
Point 11.0%
Mobile 31.0%
Point 23.0%
Area 58.0%
Area 32.0%
regulations requiring the use of
reformulated fuels. (See the Ozone
section in Chapter 2: National
Trends for Criteria Pollutants.)
Table 5-3 lists HAPs emitted from
on-road gasoline vehicles that have
emission estimates in the 1993 and
1996 NTIs. Although the EPA
addresses stationary and mobile
sources under separate regulatory
authorities and through separate
offices, these emissions are being
evaluated together in EPA's air
toxics strategies. Section 202(1)
requires EPA to regulate the
emissions of HAPs from motor
vehicles. EPA's reformulated
gasoline program requires a 15
percent year-round reduction in the
total mass of toxic emissions.
EPA's Office of Mobile Sources has
provided estimation methodologies
for the mobile source-emitted HAPs
included in the NTI.
The EPA is compiling the NTI
every three years (1993, 1996, 1999,
etc.) The emissions estimates in the
NTI, regardless of base year, have
several limitations. The NTI is a
repository of HAP emissions data
from various sources, and it varies
in quality and completeness among
source categories, geographic
location, and estimation methods.
As the process of compiling these
data is evolving, estimates will
likely improve. However, as new
base year inventories are compiled
and source category and emissions
calculation methods change,
emissions estimates are likely to
change over time because of these
factors as well as because of actual
changes in emissions.
Emissions Data
Section 112(10 Interim Inventory
for Urban HAPs
To support the regulation of area
sources in urban areas under CAA
Section 112 (k), which requires
selecting at least 30 HAPs that pose
the greatest threat to public health
in the largest number of urban
areas, EPA compiled an interim
1990 emissions inventory for
proposed urban HAPs. The EPA
conducted an analysis to compre-
hensively identify the pollutants
that pose the largest public health
threat in urban areas. The result
was a draft list of 33 urban HAPs.
Of these, 3 are emitted predomi-
nantly from major sources and 30
have emissions from multiple
source types, but with significant
contributions from area sources.
Table 5-4 lists the 33 draft urban
area source HAPs. Figures 5-5 and
5-6 present summary data from the
interim urban area emissions
inventory for the 30 HAPs signifi-
cantly associated with area sources.
Figure 5-5 indicates that area
sources account for 40 percent of
emissions of these 30 HAPs, mobile
sources account for 40 percent, and
point (major) sources account for 20
percent. Further, Figure 5-5 also
shows that urban emissions of these
30 HAPs account for 66 percent of
total emissions while rural emis-
sions account for 34 percent. Figure
5-6 summarizes source type contri-
butions of emissions of these 30
HAPs by rural and urban geo-
graphic areas. Urban geographic
areas have higher proportions of
mobile and point sources than rural
areas. The 1990 interim urban
emission inventory has undergone
extensive external and internal
review and has subsequently been
incorporated into the 1993 NTI.
The urban inventory is available at
the following website.
www.epa.gov/ttn/uatw/ 112k/
riurban.html.
It should be noted that the
percentage contributions (mobile,
point, area) shown in Figure 5-5 for
the interim urban inventory differ
significantly from those shown in
Figure 5-1 for the 1993 NTI. The
primary reason for this difference is
that the interim urban inventory
includes data for only the 30 urban
HAPs while the 1993 NTI incorpo-
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 5-5. Summary of Changes in Mean Concentration for HAPs Measured as a Part
of the PAMS Program (24-hour measurements), 1995-1997*
1995 to 1996
1996 to 1997
HAP
# Sites
# Up
# Down
# Sites
# Up
# Down
Acetaldehyde
2
0
0
4
1
1
Benzene
5
1
2
12
0
4
Ethylbenzene
5
0
2
12
0
2
Formaldehyde
2
0
0
4
1
1
Hexane
4
0
0
10
0
2
Toluene
5
0
1
12
0
1
Styrene
5
1
2
11
1
5
m/p-Xylene
5
0
0
10
0
3
o-Xylene
5
0
1
12
1
3
2,2,4-Trimethyl-
5
0
3
11
0
4
pentane
Note that the terms #Up and #Down refer to the number of sites in which the change in
annual mean concentration between 1995 and 1996, or 1996 and 1997, is a statistically
significant increase or decrease. The total number of sites (# sites) may not necessarily
equal the sum of the corresponding #Up and #Down categories.
Table 5-6. Comparison of Loading Estimates for the Great Lakes
Chemical
Year
Superior
Michigan
Huron
Erie
Ontario
(kg/yr)
(kg/yr)
(kg/yr)
(kg/yr)
(kg/yr)
PCBs (wet+dry)
1988
550
400
400
180
140
1992
160
110
110
53
42
1994
85
69
180
37
64
1996
50
42
na
34
na
DDT (wet+dry)
1988
90
64
65
33
26
1992
34
25
25
12
10
1994
17
32
37
46
16
1996
4
12
na
2
na
B(a)P (wet+dry)
1988
69
180
180
81
62
1992
120
84
84
39
31
1994
200
250
na
240
120
1996
77
117
na
160
na
Pb (wet+dry)
1988
230,000
540,000
400,000
230,000 220,000
1992
67,000
26,000
10,000
97,000
48,000
1994
51,000
72,000
100,000
65,000
45,000
1996
na
na
na
na
na
rates data for 166 HAPs. Further,
the subset of 30 pollutants included
in the interim urban inventory are
those with significant contributions
from area sources, as indicated
above. An analysis of the 1993 NTI
inventory for the subset of 30 urban
HAPs indicates similar percentage
contributions to those shown in
Figure 5-5.
Ambient Air Quality Data
Presently, there is no national
ambient air quality monitoring
network designed to perform
routine measurements of air toxics
levels. Therefore, ambient data for
individual air toxic pollutants is
limited (both spatially and tempo-
rally) in comparison to the data
available from the long-term,
nationwide monitoring for the six
criteria pollutants. EPA has several
efforts underway which, although
less effective than a comprehensive
and routine HAPs network, will
provide some information useful to
assessing the toxics issue.
The Agency's Photochemical
Assessment Monitoring Stations
(PAMS) collect data on concentra-
tions of ozone and its precursors
(VOCs and NOx) in 21 areas across
the nation classified as serious,
severe or extreme nonattainment
areas for ozone. Because a number
of ozone precursors are also air
toxics, ambient data collected from
PAMS sites can be used for limited
evaluations of toxics problems in
selected urban areas as well as
assessment of the tropospheric
ozone formation. Despite some
limitations, the PAMS sites will
provide consistent, long-term
measurements of selected toxics in
major metropolitan areas. The
CHAPTER 5: AIR TOXICS
77
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
PAMS program requires routine
measurement of 10 HAPs: acetalde-
hyde, benzene, ethyl benzene,
formaldehyde, hexane, styrene,
toluene, m/p-xylene, o-xylene and
2,2,4-trimethlypentane.
Preliminary analysis of
measurements of selected HAPs in
PAMS areas indicate that concen-
trations of certain toxic VOCs in
those areas appear to be declining.
Table 5-5 shows 2-year comparisons
for 24-hour measurements for the
ten parameters measured at PAMS
sites for the periods 1995-1996 and
1996-1997.6 For a more detailed
discussion of the PAMS program,
see the Ozone section in Chapter 2:
National Trends of Criteria Pollut-
ants.
In addition to the PAMS
program, EPA continues to admin-
ister and support voluntary pro-
grams through which states may
collect ambient air quality measure-
ments for suites of toxics. These
programs include the 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 the program dedi-
cated to toxics monitoring which
involves measurements of 37 VOCs
and 13 carbonyl compounds.7 In the
current programs, five states are
participating and operating 15
ambient measurement sites for
toxics.8 The EPA is currently
working to incorporate data from
these measurement programs into
national and local air toxics assess-
ments. Results from these analyses
will be discussed in future editions
of this report.
In addition to ambient concen-
tration monitoring, EPA also
participates in efforts to measure
the atmospheric deposition of toxic
pollution. In 1990 the U.S. and
Canada initiated a joint measure-
ment program, the Integrated
Atmospheric Deposition Network
(IADN), to assess the relative
importance of atmospheric deposi-
tion to the Great Lakes, and to
provide information about sources
of these pollutants.9 The network
consists of master (research-grade)
stations on each lake, with addi-
tional satellite stations. Two master
stations in Canada and three in the
United States were chosen to be
representative of regional deposi-
tion patterns. In addition to
collecting data on precipitation
rates, temperature, relative humid-
ity, wind speed and direction, and
solar radiation collected at each site,
IADN measures concentrations of
target chemicals in rain and snow
(wet deposition), airborne particles
(dry deposition), and airborne
organic vapors.10
Table 5-6 presents the results
of a comparison of deposition
estimates from IADN studies
performed between 1988 and 1996
(1996 loadings estimates for Lake
Huron and Lake Ontario are not yet
available). These estimates reveal a
significantly large decline in
loadings from the atmosphere of
PCBs and DDT, which would be
expected considering that use of
DDT has been restricted since 1972
and banned since 1988, and PCBs
are no longer manufactured and are
being phased out of use. The vast
majority of the PCBs and DDT
being recorded by the monitoring
network results from emissions (via
chemical volatility) from soil and
water contaminated with these
chemicals and transport to the
lakes. On the other hand,
benzo(a)pyrene (B(a)P), a by-
product of combustion processes
and one of the most toxic polycyclic
aromatic hydrocarbons yet charac-
terized, is being emitted by a
number of current sources around
the Great Lakes.
Loadings to the lakes show
some variability at each site from
year to year, probably due in part to
the range of error inherent in the
B(a)P loadings calculations and to
fluctuations in ambient concentra-
tions.11
Mercury's adverse effects on
ecological 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 regulations and
technologies aimed at reducing
mercury. The Mercury Deposition
Network (MDN) is a key element of
these efforts. A subsidiary of the
National Atmospheric Deposition
Program (NADP), the MDN
currently consists of nearly 40 sites
located in 16 States and two Cana-
dian provinces. The MDN monitors
the presence of mercury and methyl
mercury in precipitation and has
enabled scientists to compile a
national database of weekly precipi-
tation concentrations. As a result,
State and federal air regulators can
monitor progress in reducing
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
mercury 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/.
Concurrent with the monitor-
ing efforts discussed in this section,
EPA has recently initiated a pro-
gram to identify, compile and
catalogue all previously collected
monitoring data for air toxics which
is not now centrally archived. This
effort is focusing presently on the
compilation of measurements
previously made by state and local
agencies. These data will contribute
to the development of an expanded
and enhanced information infra-
structure for air toxics.12 All data
completed as a result of this effort
will be made universally accessible
to all interested programs and
analysts.
In addition, the Agency is also
sponsoring a related project to
develop environmental indicators
based on air quality monitoring
data, emissions data, modeling
data, and administrative/program-
matic data that can effectively
demonstrate the extent and severity
of the air toxics problem, and any
progress made toward solving it in
future years through regulatory or
voluntary programs. Indicators
will be included that consider
population exposure and health
risk, as well as ambient concentra-
tions and emissions. Such indica-
tors will be used to make
geographic comparisons and assess
temporal trends in subsequent
trends reports.13
Modeled Air Quality Levels
The EPA has recently developed
and demonstrated a national air
toxics modeling system, as part of
its Cumulative Exposure Project
(CEP), which has been designed to
provide a broad screening-level
quantitative perspective on outdoor
air toxics concentrations. The CEP
utilized an atmospheric dispersion
model, called ASPEN (the Assess-
ment System for Population Expo-
sure Nationwide), in conjunction
with a preliminary national emis-
sions inventory, including both
human-made and natural sources of
emissions, to estimate the ambient
air toxics concentrations for the
year 1990. The outputs generated
by the model were annual average
outdoor concentrations for 148 air
toxics, estimated at each census
tract in the continental U.S. (There
are 60,803 census tracts in the
continental U.S. which vary in
physical size but generally have
about 4,000 residents each.) Given
the inherent uncertainties involved
in computer modeling and emission
inventories, the CEP results are
most reliable when analyzed on a
national or State scale, but less so at
the county and census tract levels.
The results of this preliminary
application of the model for 1990,
although considered to include
uncertainties, indicate that outdoor
HAP concentrations may be signifi-
cantly elevated in many urban areas
when compared to rural areas, and
that many predicted levels are
relatively high, suggesting potential
public health concerns. The results
thus lend support to the decision of
Congress in 1990 to strengthen the
air toxics provisions of the Clean
Air Act. It is important to note,
however, that these preliminary
CEP estimates for 1990 do not
reflect the reality that, since that
time, the EPA and State and local
governments have issued regula-
tions that have reduced and will
continue to significantly reduce air
toxic emissions from major indus-
tries, such as chemical plants and
oil refineries, as well as from motor
vehicles. Specific results from the
1990 run of the model can be
reviewed on the Internet at http://
www.epa.gov/
CumulativeExposure.
Further development and
demonstration of the CEP modeling
approach, now referred to as CEP-
II, will represent a significant
evolution in the ability of the EPA
to assess the nature and magnitude
of the air toxics problem on a
national scale. In its CEP-II efforts,
the EPA is currently using model
performance evaluations and
improved emissions information
from State and local agencies to
update and refine the methods
employed in the original CEP
analysis. Later this year, the EPA
plans to use the CEP-II model based
on the improved 1996 NTI emis-
sions inventory. In future years,
EPA plans to continue to refine the
modeling approach and utilize
results from these model simula-
tions to help track air toxics prob-
lems and the success of efforts to
address them. Results from these
simulations will be included in
future Trends Reports to provide a
national perspective on air toxics
trends.
Air Toxics Regulation and
Implementation Status
CHAPTER 5: AIR TOXICS
79
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
The CAA greatly expanded the
number of industries affected by
national air toxics emissions
controls. Large industrial com-
plexes (major sources) such as
chemical plants, oil refineries,
marine tank vessel loading, aero-
space manufacturers, steel mills,
and a number of surface coating
operations are some of the indus-
tries being controlled for toxic air
pollution. Where warranted,
smaller sources (area sources) of
toxic air pollution such as dry
cleaning operations, solvent clean-
ing, commercial sterilizers, second-
ary lead smelters, and a chrome
plating are have also been regu-
lated. EPA estimates that over the
next 10 years the technology-based
phase of the air toxics program will
reduce emissions by 1.5 million
tons per year.14
TheMACTProgram
The technology-based regulation of
air toxics emissions is already
beginning to achieve significant
emissions reductions of HAPs. As
of September 1997, Maximum
Achievable Control Technology
(MACT) standards have been
promulgated for 52 source catego-
ries. Sixteen major- and eight area-
source categories have begun to
take action toward complying with
the standards required by the 2-
and 4-year MACT regulations.
Sources are required to comply
with these standards within three
years of the effective date of the
regulation, with some exceptions.
In October 1997, to comply with
Section 112(s), EPA released a
report to Congress describing the
status of the HAP program under
the CAA. EPA estimates that the 2-
and 4-year standards will reduce
HAP emissions by approximately
980,000 tons/year when fully
implemented.14 In addition, EPA
has promulgated regulations on
municipal waste combustors and
hospital/medical/infectious waste
incinerators under Section 129 of
the CAA. These regulations will
significantly reduce emissions of
the listed Section 129 pollutants,
including particulate matter, sulfur
dioxide, hydrogen chloride, oxides
of nitrogen, carbon monoxide, lead,
mercury, dioxins and dibenzo-
furans. For example, mercury
emissions from municipal waste
combustors are estimated to be
reduced in the year 2000 by about
98 percent from 1990 levels. When
the regulations become fully
effective, mercury emissions from
hospital/medical/infectious waste
incinerators are estimated to be
reduced by 93-95 percent from 1995
levels.
The air toxics program and
other air pollution programs, such
as the NAAQS program, comple-
ment each other. Many air toxics
are also particulate matter (PM) or
VOCs which can be ozone precur-
sors. As such, many control efforts
to meet the NAAQS for ozone and
PM10 also reduce air toxic emis-
sions. Furthermore, as air pollution
control strategies for automobiles
become more stringent, air toxic
emissions from vehicles also are
reduced. Requirements under the
air toxics program can also signifi-
cantly reduce emissions of some of
the six NAAQS pollutants. For
example, MACT standards are
predicted to reduce approximately
1.8 million tons per year in com-
bined emissions of particulate
matter and VOC as ozone precur-
sors. EPA's final air toxics rule for
organic chemical manufacturing
alone is expected to reduce VOC
emissions by nearly 1 million tons
annually.
The Specific Pollutants Strategy
Section 112(c)(6) of the CAA
requires EPA to identify sources of
seven specific compounds (alky-
lated lead compounds, POM,
mercury, hexachlorobenzene, PCBs,
2,3,7,8-tetrachlorodibenzo-p-dioxin,
and 2,3,7,8-tetrachlorodibenzo-
furan), and to regulate sources
accounting for at least 90 percent of
the emissions of each pollutant.20
MACT standards must be devel-
oped by EPA for sources of these
HAPs that are not subject to current
MACT standards. In order to meet
the requirements of Section
112(c)(6), EPA compiled national
inventories of sources and emis-
sions of each of the seven HAPs,
and identified source categories for
regulation.15
The Integrated Urban Air Toxics
Strategy
To address the problem of exposure
to air toxics in urban areas, EPA is
developing an integrated urban air
toxics strategy that addresses the
urban air toxics risks from both
stationary and mobile sources.
This strategy is expected to produce
a set of actions that will be more
responsive to the cumulative risks
presented by multiple sources of
toxics and combined exposures to
multiple toxics. By considering
urban air toxics emissions from all
sources, EPA will better respond to
the relative risks posed by any one
pollutant and/or source category.
Thus, integration of the activities
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
under both the air toxics and
mobile source sections of the Act
will more realistically address the
total exposure and will better allow
us and the States to develop activi-
ties to address risks posed by toxic
pollutants where the emissions and
risks are most significant and
controls are most cost effective.
Under the urban program,
EPA's first phase regulatory task is
to identify at least 30 HAPs that are
of particular concern when emitted
in urban areas, especially from area
sources. Then, EPA is to reduce
risks from these pollutants, first by
regulating sources that account for
90 percent of the emissions of the
HAPs of concern. Regulations of
area sources under this program
can be with MACT or GACT
regulations. In September of 1998,
EPA released a draft of the Inte-
grated Urban Air Toxics Strategy to
the public for comment. In the
draft strategy, EPA provided, a
draft list of 33 HAPs that are of
particular concern when emitted in
urban areas, including a subset of
30 particularly relevant to area
sources. EPA also provided a draft
list of area source categories that
may require regulation in the future
to meet the "90% requirement".
This list may change before it is
published as final.
After identifying the HAPs
and their sources, EPA will examine
the MACT, vehicle fuels and
emissions program, and other air
toxics-related programs, including
State and local programs, to assess
the risk reduction that can be
reasonably expected once these
other programs have been fully
implemented. Then EPA will
identify what additional controls
may be needed. Since point, area,
and mobile sources in urban areas
emit many of the same pollutants
EPA believes this integrated
approach is the most efficient and
cost-effective way to address the
health risks attributable to exposure
to air toxics in urban areas. In the
draft strategy published in Septem-
ber of 1998, EPA included schedules
for potential actions to address
HAP emissions from mobile
sources and stationary sources
(including consideration of the
requirements to reduce cancer risk
from these sources by at least 75
percent and to substantially reduce
other risks). Schedules for develop-
ing tools and databases to better
understand cumulative exposures
to HAPs were also included in the
draft strategy.16
Residual Risk
To determine whether risks are
acceptable after the application of
MACT standards, Congress added,
in Section 112(f), a human health
risk and adverse environmental
effects criteria to the second regula-
tory phase. In this phase, referred
to as "residual risk" standard
setting, EPA is required to promul-
gate additional standards for those
source categories that are emitting
HAPs at levels that present an
unacceptable risk to the public or
the environment. Congress di-
rected that residual risk standards
should "provide an ample margin
of safety to protect public health."
Risks of cancer and other health
effects, as well as the potential for
adverse environmental effects will
be considered in setting residual
risk standards. Using a risk man-
agement framework, EPA is cur-
rently conducting residual risk
assessments to determine whether
technology-based emission stan-
dards are sufficient to protect
human health. The first rules, if
necessary, are due in 2002.
EPA is also required by
Section 112 (f) (1) of the Act to
provide a report to Congress
describing the methodology of
approaches assessing these residual
risks, the public health significance
of any remaining risks, and techni-
cal and economic issues associated
with controlling the risks. The
report is currently scheduled for
publication in early 1999.
Special Studies/Programs
The Great Waters Program
Section 112(m) of the CAA requires
the Agency to study and report to
Congress every two years on the
extent of atmospheric deposition of
HAPs and other pollutants to the
Great Lakes, Chesapeake Bay, Lake
Champlain, and coastal waters, and
the need for new regulations to
protect these water bodies. The
pollutants of concern to this effort
include mercury, chlorinated
organics and other persistent,
bioaccumulating HAPs, as well as
nitrogen compounds. This program
coordinates with extensive research
programs to provide new under-
standing of the complicated issue of
atmospheric deposition of air
pollution to water bodies. New
scientific findings are incorporated
into each required biennial report to
Congress and appropriate regula-
tory recommendations are made as
warranted by those findings. This
statute provides the authority to
CHAPTER 5: AIR TOXICS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
introduce new regulations or
influence those under development
in order to prevent adverse effects
from these pollutants to human
health and the environment.
The Mercury Study
The Mercury Study is a comprehen-
sive study of mercury emissions
from anthropogenic sources in the
United States, an assessment of the
public health and ecological effects
of such emissions, and an analysis
of technologies to control mercury
emissions, and the costs of such
control. The study is mandated by
Section 112(n)(l)(B) of the CAA
because mercury is, as an element,
eternally persistent, as well as
bioaccumulative and the cause of
fish consumption advisories in
more than 39 States. A number of
observations can be made regarding
trends in mercury use and emis-
sions. The overall use of mercury
by industrial and manufacturing
source categories has significantly
declined. Industrial use of mercury
declined by nearly 75 percent
between 1988 and 1995. Much of
this decline can be attributed to the
elimination of mercury as a paint
additive and the phase-out of
mercury in household batteries.
Reducing mercury in manufactured
products is important because
emissions of mercury are most
likely to occur when these products
are broken or discarded. Based on
trends in mercury use, EPA predicts
that manufacturing use of mercury
will continue to decline. Chlorine
production from mercury cell chlor-
alkali plants will continue to
account for most of the use in, and
emissions from, the manufacturing
sector. This industry has indicated
it will voluntarily reduce mercury
use by 50 percent by 2006. Second-
ary production of mercury may
increase as more recycling facilities
begin operations to recover mer-
cury from discarded products and
wastes. A significant decrease will
occur in mercury emissions from
municipal waste combustors and
medical waste incinerators when
the final regulations promulgated
by EPA for these source categories
are fully implemented. Emissions
from both categories will decline by
at least 90 percent from 1995 levels;
to roughly 6 tons per year from
municipal waste combustors and 1
ton per year from medical waste
incinerators. In addition, EPA has
proposed mercury emission limits
for hazardous waste combustors.
Based on 1995 estimates, coal-fired
utility boilers are the largest source
category at 52 tons per year. Future
mercury emissions from utility
boilers depend on a number of
factors including the nation's
energy needs, fuel choices, industry
restructuring and other require-
ments under the CAA (e.g., the acid
rain program). A recent EPA
analysis also predicted mercury
emissions will decline at least 11
tons per year as a result of imple-
mentation of the ambient standards
for fine particulate matter. Interna-
tional efforts to reduce greenhouse
gases will also reduce mercury
emissions. The Mercury Study
Report to Congress was completed
in December 1997.5
The Utility Air Toxics Study
As mandated by Section
112(n)(l)(A) of the CAA, the
Agency has completed a study of
HAP emissions from fossil fuel-
fired (coal, oil, and gas) electric
utilities, the associated hazards to
public health, as well as an assess-
ment of alternative emissions
control strategies. EPA released a
final report from this study in
February, 1998.17 The report identi-
fies 67 HAPs emitted from electric
utilities, and predicts that by the
year 2010 a 30 percent increase in
HAP emissions from coal-fired
utilities while emissions from oil-
fired utilities are estimated to
decline by 50 percent. Though
substantial uncertainties exist in
these future emission estimates,
they are based on projected energy
demands, changes in fuel mix at
utilities, and expected emission
reductions from the Acid Rain
Program. While significant uncer-
tainty exists regarding the risks
posed from HAP emissions, the
main pollutants of concern from
electric utilities include: mercury,
arsenic, nickel, and dioxin. Due to
the uncertainties mentioned, the
Agency has deferred a final deci-
sion on the need for additional
control of HAP emissions from
electric utilities until more informa-
tion on this industry is available.
References
1. This list originally included 189
chemicals. The CAA allows EPA to
modify this list if new scientific
information becomes available that
indicates a change should be made.
Using this authority, the Agency
modified the list to remove capro-
lactam in 1996, reducing the list to
188 pollutants (Hazardous Air
Pollutant List; Modification, 61 FR
30816, June 18, 1996).
2. "Update: Listing of Fish and
Wildlife Advisories," announcing
the availability of the 1996 update
for the database: Listing of Fish and
82
CHAPTER 5: AIR TOXICS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Wildlife Advisories (LFWA); U.S.
EPA Fact Sheet, EPA-823-97-007,
June 1997.
3. Hillery, B.R., Hoff, R.M., and
Hites, R.A. 1997. "Atmospheric
contaminant deposition to the Great
Lakes determined from the Inte-
grated Atmospheric Deposition
Network." Chapter 15 in Atmo-
spheric Deposition of Contaminants
to the Great Lakes and Coastal
Waters. 1997, Joel E. Baker, Editor.
SETAC Press. (Society of Environ-
mental Toxicology and Chemistry.)
4. In addition to the absence of
emissions estimates for area and
mobile source categories, there are
other significant limitations in the
TRI's portrayal of overall HAP
emissions. First, facilities with
Standard Industrial Classification
(SIC) codes outside the range of 20
to 39 (the manufacturing SICs) are
not required to report. Therefore,
HAP emissions from facilities such
as mining operations, electric
utilities, and oil and gas production
operations are not represented in
the TRI. Further, TRI data are self-
reported by the emitting facilities,
and TRI does not require facilities
to perform any actual monitoring or
testing to develop their reported
estimates. Consequently, the
accuracy of the reported data may
vary from facility to facility and
from year to year. Finally, the
original TRI list only required
reporting for 173 of the 188 HAPs
identified in the CAA.
5. Mercury Study Report to Con-
gress. Volume II. An Inventory of
Anthropogenic Mercury Emissions
in the United States. EPA-452/R-
97 004b. The report can also be
access via the internet at: http://
www.epa.gov/ttnuatwl/112nmerc/
mercury.html
6. Summaries of the health effects
associated with the compounds
included in this analysis are pro-
vided below:
Acetaldehyde: The primary effects
on humans, reported from short-
term exposure to low to moderate
levels of acetaldehyde, are irritation
of eyes, skin, and respiratory tract.
Short-term exposure effects on
animals also include slowed
respiration and elevated blood
pressure. Effects on humans from
long-term acetaldehyde exposure
resemble those of alcoholism.
Long-term exposures of animals
have resulted in changes in respira-
tory tract tissues, as well as growth
retardation, anemia, and kidney
effects. While no information is
available on acetaldehyde effects on
human reproduction or develop-
ment, both such effects have been
observed in animal tests. Based on
evidence of tumors in animals, EPA
has classified acetaldehyde as a
probable human carcinogen.
Benzene: Reported effects on
humans, from short-term exposure
to low to moderate benzene levels,
include drowsiness, dizziness,
headache, and unconsciousness as
well as eye, skin and respiratory
tract irritation. Effects on both
humans and animals from long-
term benzene exposure include
blood and immune system disor-
ders. Reproductive effects have
been reported for women exposed
to high benzene levels and adverse
effects on the developing fetus have
been observed in animal tests.
Changes in human chromosome
number and structure have been
reported under certain exposures.
EPA has classified benzene as a
known human carcinogen.
Formaldehyde: Reported effects on
humans, from short-term and long-
term exposure to formaldehyde, are
mainly irritation of eyes, nose,
throat, and, at higher levels, the
respiratory tract. Long-term
exposures of animals have also
resulted in damage to respiratory
tract tissues. Although little
information is available on develop-
mental effects to humans, animal
tests do not indicate effects on fetal
development. EPA has classified
formaldehyde as a probable human
carcinogen.
Toluene: Effects on the CNS of
humans and animals have been
reported, from short-term exposure
to low to moderate levels of tolu-
ene, and include dysfunction,
fatigue, sleepiness, headaches, and
nausea. Short-term exposure effects
also include cardiovascular symp-
toms in humans and depression of
the immune system in animals.
CNS effects are also observed in
long-term exposures of humans and
animals. Additional long-term
exposure effects include irritation of
eyes, throat and respiratory tract in
humans and changes in respiratory
tract tissue of animals. Repeated
toluene exposure has been observed
to adversely affect the developing
fetus in humans and animals. Due
to a lack of information for humans
and inadequate animal evidence,
EPA does not consider toluene
classifiable as to human carcinoge-
nicity.
Xylenes: Reported effects on
humans, from short-term exposure
to high levels of xylenes, include
CHAPTER 5: AIR TOXICS
83
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
irritation of eyes, nose, and throat,
difficulty breathing, impairment of
the CNS and gastrointestinal
effects. Similar effects have been
reported in animals in addition to
effects on the kidney. Human
effects from long-term exposure to
xylenes are to the CNS, respiratory
and cardiovascular systems, blood,
and kidney. Long-term animal
exposures to high levels of xylenes
have shown effects on the liver.
Effects on the developing fetus have
been observed in animal studies.
Due to a lack of information for
humans and inadequate animal
evidence, EPA does not consider
xylenes classifiable as to human
carcinogenicity.
Ethylbenzene: Effects reported,
from short-term exposures of
humans to high levels of ethyl
benzene, include dizziness, depres-
sion of the CNS, eye, mucous
membrane, nose and respiratory
tract irritation, and difficulty
breathing. In short-term exposures
of laboratory animals, additional
effects on the liver, kidney and
pulmonary system have also been
reported. Long-term exposures of
animals have demonstrated effects
on blood cells, the liver and kid-
neys. Effects on fetal development
have also been observed in animal
exposures. Due to a lack of infor-
mation for humans and inadequate
animal evidence, EPA does not
consider ethyl benzene classifiable
as to human carcinogenicity.
Styrene: Exposure to styrene
vapors can cause irritation of eyes,
nose, throat and respiratory tract in
humans. Effects on the CNS of
humans including dizziness,
fatigue, sleepiness, headaches,
nausea, and effects on intellectual
function and memory have also
been reported from long-term
exposure to styrene. Long-term
exposures of animals have demon-
strated effects on the CNS, liver and
kidney as well as eye and nasal
irritation. Although the available
information for humans is inconclu-
sive, animal tests do not indicate
effects on reproduction or fetal
development. When styrene is
absorbed into the human body,
some of it is metabolized into
styrene oxide, a direct acting
mutagen that causes tumor
developmen in test animals. The
carcinogenicity of styrene is cur-
rently under review by EPA.
Hexane: Reported effects on
humans, from short-term exposure
to high levels of hexane, include
irritation of eyes, mucous mem-
branes, throat and skin, as well as
impairment of the CNS including
dizziness, giddiness, headaches,
and slight nausea. Long-term
human exposure from inhalation is
associated with a slowing of
peripheral nerve signal conduction
which causes numbness in the
extremities and muscular weakness,
as well as changes to the retina
which causes blurred vision.
Animal exposures to hexane have
resulted in damage to nasal,
respiratory tract, lung and periph-
eral nerve tissues, as well as effects
on the CNS. No information is
available on hexane effects on
human reproduction or develop-
ment. Limited laboratory animal
data indicate a potential for testicu-
lar damage in adults, while several
animal studies show no effect on
fetal development. EPA has not
classified hexane as to human
carcinogenicity.
2,2,4-Trimethylpentane: Little
information is available on the
effects of 2,2,4-trimethylpentane
overexposure in humans. Labora-
tory animals exposed to high levels
for short periods have developed
irritation, fluid build-up and
bleeding in the lungs, as well as
depression of CNS function.
Kidney and liver effects have been
reported from long-term animal
exposures. No information is
available on the potential for
reproductive or developmental
effects or on the carcinogenic
potential of 2,2,4-trimethylpentane.
7. Twenty-eight of the 37 VOCs,
and four of the 13 carbonyls mea-
sured as a part of the UATMP are
defined as HAPs in section
112(b)(1) of the CAA.
8. The following states are pres-
ently participating in the UATMP:
Arkansas, Louisiana, New Jersey,
Texas, and Vermont.
9. The IADN fulfills legislative
mandates 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 deposi-
tion network.
10. The target chemicals include
PCBs, pesticides, PAHs and metals.
The compounds included as "target
chemicals" were selected based on
the following criteria: presence on
List 1 of Annex 1 of the Great Lakes
Water Quality Agreement (sub-
stances believed to be toxic and
84 CHAPTER 5: AIR TOXICS
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
present in the Great Lakes); estab-
lished or perceived water quality
problem; presence on the Interna-
tional Joint Commission's Water
Quality Board's list of criteria
pollutants; evidence of presence in
the atmosphere and an important
deposition pathway; and feasibility
of measurement in a routine
monitoring network.
11. Hoff, R.M., Strachan, W.M.J.,
Sweet, C.W., D.F. Gatz, Harlin, K.,
Shackleton, M., Cussion, S., Chan,
C.H., Brice, K.A., Shroeder, W.H.,
Bidleman, T.F., Atmospheric
Deposition of Toxic Chemicals to
the Great Lakes: A Review of Data
Through 1994, Atmos. Environ.,
1996, 30, 3505-3527. For additional
references see A, B, C listed below.
A. Hornbuckle, K.C.,
Jeremaison, J.D., Sweet, C.W.,
Eisenreich, S., "Seasonal
Variations in Air-Water Ex-
change of Polychlorinated
Biphenyls in Lake Superior", J.
Environ. Sci. Technol. 1994, 28,
1491-1501.
B. Hillery, B.R., Basu I., Sweet,
C.W., Hites, R.A., Temporal
and Spatial Trends in a Long-
Term Study of Gas-Phase PCB
Concentrations near the Great
Lakes, Environ. Sci. Technol.
1997, 31, 1811-1816.
C. Hillery, B.R., Hoff, R.M.,
Hites, R. Atmospheric Contami-
nant Deposition to the Great
Lakes Determined from the
International Atmospheric
Deposition Network, In Atmo-
spheric Deposition of Contami-
nants to the Great Lakes and
Coastal Water, Baker, J.E., ed.,
Society for Environmental
Toxicology and Chemistry,
1997.
12. Interest in participation in this
voluntary effort and/or requests for
further information about this data
cataloguing effort should be
directed to Rhonda Thompson,
Office of Air Quality Planning and
Standards, Mail Drop 14, Research
Triangle Park, North Carolina
27711; 919-541-5538; and
thompson.rhonda@epa.gov.
13. The scheduled completion date
for this project is April 1999;
however, interim products will be
released as completed. Additional
information on this project is
available through Vasu Kilaru,
Office of Air Quality Planning and
Standards, Mail Drop 14, Research
Triangle Park, North Carolina
27711: 919-541-5332; and
kilaru.vasu@epa.gov.
14. Second Report to Congress on
the Status of the Hazardous Air
Pollutant Program Under the CAA,
Draft. EPA-453/R-96-015. October
1997.
15. The final inventory report is
available at the following Internet
address: www.epa.gov/ttn/uatw/
112cfac.html.
16. The draft inventory report is
available at the following Internet
address: www.epa.gov/ttn/uatw/
112kfac.html
17. Study of Hazardous Air Pollutant
Emissions from Electric Utility Steam
Generating Units - Final Report to
Congress: Volume 1, U.S. EPA 1998.
EPA 453/R-98-004a.
CHAPTER 5: AIR TOXICS
85
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
86 CHAPTER 5: AIR TOXICS
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6
Visibility Trends
http://www.epa.gov/oar/aqtrnd97/chapter6.pdf
Introduction
The Clean Air Act (CAA) authoriz-
es the United States Environmental
Protection Agency (EPA) to protect
visibility, or visual air quality,
through a number of programs.
These programs include the nation-
al visibility program under sections
169A and 169B of the Act, the pre-
vention of significant deterioration
program for the review of potential
impacts from new and modified
sources, the secondary National
Ambient Air Quality Standards
(NAAQS) for PMi0 and PM2.s and
section 401 under the provisions for
acid deposition control. The na-
tional visibility program established
in 1980 requires the protection of
visibility in 156 mandatory federal
Class I areas across the country
(primarily national parks and wil-
derness areas). The CAA estab-
lished as a national visibility goal,
"the prevention of any future, and
the remedying of any existing, im-
pairment of visibility in mandatory
federal Class I areas in which im-
pairment results from manmade air
pollution." The Act also calls for
state programs to make "reasonable
progress" toward the national goal.
In 1987, the Interagency Moni-
toring of Protected Visual Environ-
ments (IMPROVE) visibility net-
work 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 Management, the
U.S. Fish & Wildlife Service, and
State governments. The objectives
of the network are to establish cur-
rent conditions, to track progress
toward the national visibility goal
by documenting long-term trends,
and to provide information for de-
termining the types of pollutants and
sources primarily responsible for
visibility impairment. Chemical
analysis of aerosol measurements
provides ambient concentrations
and associated light extinction for
PMio, PM2.5, sulfates, nitrates, or-
ganic and elemental carbon, crustal
material, and a number of other
elements. The IMPROVE program
has established protocols for aero-
sol, optical, and photographic mon-
itoring methods, and these methods
are employed at more than 70 sites,
most of which are Class 1 areas.
Over the next few years, an addi-
tional 78 monitoring sites using the
IMPROVE protocol will be estab-
lished. 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
between 1988 and 1997 at 37 Class I
areas in the IMPROVE network.
Because the CAA calls for the track-
ing of "reasonable progress" in
preventing future impairment and
remedying existing impairment,
this analysis looks at trends in visi-
bility impairment across the entire
range of the visual air quality distri-
bution. To facilitate this approach,
visibility data have been sorted into
quintiles, or 20 percent segments of
the overall distribution, and aver-
age values have been calculated for
each quintile. Trends are often
presented in terms of the haziest
("worst") 20 percent, middle 20
percent, and clearest ("best") 20
percent of the annual distribution of
data. Figure 6-1 provides a photo-
graphic illustration of very clear
and very hazy conditions at Glacier
National Park in Montana, and
Dolly Sods Wilderness Area in
West Virginia.2 Figure 6-3 is a map
of the 37 Class I areas with 6 or
more years of IMPROVE monitor-
ing 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
CHAPTER 6: VISIBILITY 87
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Condition:
Bad
Visual Range:
15-25 km
Deciviews:
33-28
Condition: Good
Visual Range:
150-200 km
Deciviews:
10-7
Condition: Bad
Visual Range:
<10 km
Deciviews:
>37
Condition: Good
Visual Range:
80-140 km
Deciviews:
16-10
Glacier National Park
Dolly Sods Wilderness
Figure 6-1. Images of Glacier National Park and Dolly Sods WA.
in the atmosphere. It is most sim-
ply described as the haze that ob-
scures the clarity, color, texture, and
form of what we see. The same
particles linked to serious health
and environmental effects (sulfates,
nitrates, organic carbon, elemental
carbon [commonly called soot], and
crustal material) can also signifi-
cantly affect our ability to see.
Both primary emissions and
secondary formation of particles
contribute to visibility impairment.
Primary particles, such as elemental
carbon from diesel and wood com-
bustion or dust from certain indus-
trial activities or natural sources,
are emitted directly into the atmo-
sphere. Secondary particles that are
formed in the atmosphere from
primary gaseous emissions include
sulfate from sulfur dioxide (S02)
emissions, nitrates from nitrogen
oxide (NOx) emissions, and organic
carbon particles formed from con-
densed hydrocarbon emissions. In
the eastern United States, reduced
visibility is mainly attributable to
secondarily formed particles, partic-
ularly those less than a few mi-
crometers in diameter. While sec-
ondarily formed particles still
account for a significant amount in
the West, primary emissions from
sources such as woodsmoke gener-
ally contribute a larger percentage
of the total particulate load than in
the East. The only primary gaseous
pollutant that directly reduces visi-
bility is nitrogen dioxide (N02),
which can sometimes be seen in a
visible plume from an industrial
facility, or in some urban areas with
high levels of motor vehicle emis-
sions.
Visibility conditions in rural
Class I areas vary regionally across
the United States. Rural areas in
the East generally have higher lev-
els of impairment than most remote
sites in the West. Higher eastern
levels are generally due to higher
regional concentrations of sulfur
dioxide and other anthropogenic
emissions, higher estimated region-
al background levels of fine parti-
cles, and higher average relative
humidity levels. Humidity can
significantly increase the effect of
pollution on visibility. Some parti-
cles, 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
88 CHAPTERS: VISIBILITY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
as compared to 50-60 percent in the
West. Poor summer visibility in the
eastern United States is primarily
the result of high sulfate particle
concentrations combined with high
humidity levels.
Visibility conditions are com-
monly expressed in terms of three
mathematically related metrics:
visual range, light extinction, and
deciviews. Visual range is the met-
ric best known by the general pub-
lic. It is the maximum distance at
which one can identify a black ob-
ject against the horizon, and is typi-
cally described in miles or kilome-
ters. Light extinction, inversely
related to visual range, is the sum
of light scattering and light absorp-
tion by particles and gases in the
atmosphere. It is typically ex-
pressed in terms of inverse mega-
meters (Mm1), with larger values
representing poorer visibility. Un-
like visual range, the light extinc-
tion coefficient allows one to
express the relative contribu-
tion of one particulate matter
(PM) constituent versus an-
other to overall visibility im-
pairment. Using speciated
mass measurements 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 sum-
ming these values for each
constituent. Because sulfates
and nitrates become more
efficient at scattering light
with increasing humidity,
these values are also multi-
plied by a relative humidity
adjustment factor.3 Annual
and seasonal light extinction values
developed by this approach corre-
late well with optical measurements
of light extinction (by transmissom-
eter) and light scattering (by
nephelometer).
The deciview metric was de-
veloped because changes in visual
range and light extinction are not
proportional to human perception.
For example, a 5-mile change in
visual range can be either very ap-
parent or not perceptible, depend-
ing 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 condi-
tions, a change of one deciview is
considered to be perceptible by the
average person. A deciview of zero
represents pristine conditions.
Clean
It is important to understand
that the same amount of pollution
can have dramatically different
effects on visibility depending on
existing conditions. Most impor-
tantly, visibility in cleaner environ-
ments is more sensitive to increases
in PM2.5 particle concentrations
than visibility in more polluted
areas. This principle is illustrated
in Figure 6-2, which characterizes
visibility at Shenandoah National
Park under a range of conditions.5
A clear day at Shenandoah can be
represented by a visual range of 80
miles, with conditions approximat-
ing naturally-occurring visibility
(i.e., without pollution created by
human activities). An average day
at Shenandoah is represented by a
visual range of 18 miles, and is the
result of an additional 10 g/m3 of
fine particles in the atmosphere.
The two bottom scenes, with visual
ranges of eight and six miles respec-
Clean Day + 10 ug/m3
Standard Visual Range = 80 Miles Standard Visual Range = IS Miles
Dirty Day + 10 ug/m3
Dirty Day
Figure 6-2. Shenandoah National Park on clear and hazy days and the effect of adding
10ug/m3of fine particles to each.
CHAPTER 6: VISIBILITY 89
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 6-3. 37 Class I Areas in the IMPROVE Network with at least 6 years of data.
~
Mount Rainier
Boundary Waters Canoe Area
da NP
+Crater Lake N
ye Brook
^Badlands np
n Volcanic N
Brlgantlne N
main NP
eyes
*Yo8emlte NP
~
Pinnacles N
yonlands NP
dDunes
nyon N
Smoky Mountai
-A-Bandelle
fled Forest NP
(Superstition) NM
San Go
Chlrlcanua NM
nokee NWR
Guadalupe Mountains NP
Big Bend
Denali NP
Legend
NP = National Park
W = Wilderness
NWR = National Wildlife Refuge
NS = National Seashore
NM = National Monument
tively, illustrate that the perceived
change in visibility due to an addi-
tional 10 g/ 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
perceived visibility improvement, a
larger reduction in fine particle
concentrations is needed in more
polluted areas. Conversely, a small
amount of pollution in a clean area
can dramatically decrease visibility.
Long-Term Trends
Visibility impairment is presented
here using visual range data collect-
ed 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 visibility.
Overall, these maps show that sum-
mer visibility in the eastern United
States declined between 1970 and
1980, and improved slightly be-
tween 1980 and 1990. These trends
follow overall trends in emissions
of sulfur oxides during these peri-
ods.
Recent Trends in Rural
Areas: 1988-1997
Aerosol and light extinction data
have been collected for 10 consecu-
tive years (1988-1997) at 30 sites in
the IMPROVE network, and for 6
consecutive years (1992-1997) at 11
sites in the network. Of these 41
sites, 4 sites (Washington,
D.C.; Bliss State Park, CA;
Great Basin NP, NV; and
Sequoia NP, CA) were
omitted from the analyses
in this chapter for reasons
of missing data or loca-
tion in an urban area.
Washington, DC is the
only urban location. The
remaining 37 represent
rural Class I areas: eleven
are located in the East,
and 26 are located in the
West, as shown in Figure
6-3. Because of the signif-
icant regional variations
in visibility conditions,
this chapter does not
present aggregate nation-
al trends, but instead
groups the data into east-
ern and western regions.
As noted earlier, trends in this
chapter are frequently presented in
terms of the annual average values
for the clearest ("best") 20 percent,
middle 20 percent, and haziest
("worst") 20 percent of the days
monitored each year. To date, two
24-hour aerosol samples have been
taken each week from IMPROVE
sites, resulting in a potential for 104
sampling days per year. Beginning
in 1999, aerosol samples will be
taken every 3 days, consistent with
the approach used for new PM2.5
aerosol monitoring.
Regional Visibility Trends
for the Eastern and West-
ern United States
Figures 6-5a and 6-5b illus-
trate eastern and western trends for
total light extinction. These figures,
presented with equivalent scales,
demonstrate the regional difference
90 CHAPTER 6: VISIBILITY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
in overall levels of visibility impair-
ment. 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 eight additional east-
ern sites are reflected in Figure 6-5a
beginning in 1992, bringing to elev-
en the total number of eastern sites
reflected in the values plotted in
Figure 6-5a for 1992-97. By adding
the 8 eastern sites to the dataset, the
magnitude of average impairment
levels has increased, although the
general slope of the trends for clear-
est, middle, and haziest days ap-
pear 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. Eastern impairment on
the haziest days reached a low
point in 1993, but both the 3- and
11- site trends have increased by
about 4% by 1997. The best visibili-
ty days appear to be relatively flat
or improving slightly. The middle
20 percent of the distribution ap-
pears to have a downward trend
exceeding 10 percent for both the 3-
sites and 11-site lines.
In the West, there appears to
be steady visibility improvement in
each of the 3 quintiles presented in
Figure 6-5b for the period 1988-
1997. Total light extinction for the
aggregation of 26 western sites
declined by 11-14 percent for each
of the 3 categories. In the East, the
average deciview value for the
worst visibility days increased by
about 0.5, while in the West, the
average value decreased by 1.5
deciviews.
The area plots in Figures 6-6a
through 6-6f show the relative con-
tribution to aerosol light extinction
Figure 6-4. Long-term trend for 75th percentile light coefficient from airport
visual data (July-September).
CHAPTER 6: VISIBILITY 91
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
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 components. By under-
standing the total magnitude of
each PM2.5 component, the change
in aerosol composition over time,
and the effect of these components
on changing visibility, policymak-
ers can design strategies to address
health and environmental concerns.
In the East, (Figures 6-6a, b,
and c), sulfate is clearly the largest
contributor to visibility impairment,
ranging from 64 percent of aerosol
extinction during the best days to
80% on the worst days. Since reach-
ing a low point in 1993, light extinc-
tion due to sulfate has increased
slightly about 7 percent by 1997.
Organic carbon is the next largest
contributor to visibility impairment
in the East, accounting for 12 per-
cent of aerosol extinction on the
best days and averaging 9 percent
on the most impaired days. Over
the period 1992-1997, the contribu-
tion of organic carbon to aerosol
light extinction appears to be de-
clining for the clearest, middle, and
haziest days. The third largest con-
tributor in the East is nitrate, which
also accounts for about 12 percent
of aerosol light extinction on the
best days and about 5 percent on
the haziest days.
In the West, sulfate is also the
most significant single contributor
to aerosol light extinction on the
best, middle, and worst 20 percent
days of the distribution. Sulfate
typically accounts for 35-45 percent
of aerosol light extinction. Howev-
er, organic carbon (19-22 percent),
crustal material (16-20 percent), and
nitrates (12-15 percent) play a more
significant role (as a percentage of
aerosol extinction) in western sites
than eastern ones. Based on this
aggregation of 26 sites, it appears
that organic carbon and elemental
carbon are showing downward
trends in western Class I areas.
Trends in Specific Class I Areas
IMPROVE data from 37 Class I area
monitoring sites (29 with data for
1988-1997, 8 with data for 1992-
1997) were analyzed for upward or
Light Extinction, Mm-1
200
Haziest 20 percent
3 Sites having data for all ten years
11 Sites - original 3 plus 8 additional
sites having data from 1992 to 1997
Middle 20 percent
Clearest 20 percent
88 89 90 91 92 93 94 95 96 97
Light Extinction, Mm-1
200
150
100
50
26 Sites
Haziest 20 percent
Middle 20 percent
Clearest 20 percent
89 90 91 92 93 94 95 96 97
Figure 6-5a. Total light extinction trends for eastern Class I
areas for haziest, middle, and clearest 20 percent of the distri-
bution, 1988-1997.
Figure 6-5b. Total light extinction trends for western Class
I areas for haziest, middle, and clearest 20 percent of the
distribution, 1988-1997.
92 CHAPTER 6: VISIBILITY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
downward trends using a nonpara-
metric regression methodology
described in Chapter 3: Criteria
Pollutants - Metropolitan Area
Trends.
Table 6-1 summarizes the
trends analysis performed on these
37 sites for total light extinction
(expressed in deciviews), light ex-
tinction due to sulfate, and light
extinction due to organic carbon.
Overall, about one-fourth of
the sites showed a significant
downward trend in deciviews on
the worst days, and more than one-
third of the sites exhibited a signifi-
cant improvement in visibility on
the best days. Only a few sites
showed a significant downward
trend for light extinction due to
sulfate, whereas one-half to three-
fourths of the sites demonstrated
significant improvements in light
extinction due to organic carbon.
Two sites were found to have statis-
tically significant upward trends for
the 9 parameters presented: Bad-
lands National Park (SD) showed a
significant upward trend in deci-
views for the worst days, and San
Gorgonio Wilderness (CA) showed
a significant positive trend for light
extinction due to sulfate. Several
other sites also had positive slopes
for various parameters, indicating
some degree of an upward trend. A
review of the annual data plotted
Figure 6-6a. Aerosol light
extinction in eastern Class I
areas for the clearest 20
percent of the distribution,
1988-1997.
Aerosol Light Extinction, Mm-1
200
~ Sulfate
~ Elemental Carbon
~ Organic Carbon
¦ Nitrate
~ Crustal Material
Figure 6-6b. Aerosol light
extinction in eastern Class I
areas for the middle 20
percent of the distribution,
1988-1997.
Figure 6-6c. Aerosol light
extinction in eastern Class I
areas for the haziest 20
percent of the distribution,
1988-1997.
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 1988-1991 trend is based
on the 3 sites with available data. Beginning in 1992 and going
through 1997, there are 8 additional sites with trend data.
100
3 Sites
11 Sites
90 91 92 93 94 95 96 97
Aerosol Light Extinction, Mm-1
200
100
3 Sites
11 Sites
89 90 91 92 93 94 95 96 97
Aerosol Light Extinction, Mm-1
200
150
3 Sites
11 Sites
CHAPTER 6: VISIBILITY 93
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Aerosol Light Extinction, Mm-1
50
26 Sites
Figure 6-6d. Aerosol light
extinction in western Class I
areas for the clearest 20 per-
cent of the distribution, 1988-
1997.
~ Sulfate
~ Elemental Carbon
~ Organic Carbon
¦ Nitrate
~ Crustal Material
89
90
92
93
94
95
96
97
Aerosol Light Extinction, Mm-1
50
26 Sites
Figure 6-6e. Aerosol light
extinction in western Class I
areas for the middle 20 percent
of the distribution, 1988-1997.
Aerosol Light Extinction, Mm-1
50
40
30
20
26 Sites
Figure 6-6f. Aerosol light
extinction in western Class I
areas for the haziest 20 percent
of the distribution, 1988-1997.
for each site as well as the results
from the nonparametric regression
method described in Chapter 3
shows that several sites have posi-
tive slopes and should be moni-
tored closely for potential upward
trends for either the best, middle, or
worst 20 percent of the days in the
distribution. Table 6-2 lists those
sites which may be of potential
concern.
Current Conditions
Current annual average conditions
range from about 18-40 miles in the
rural East and about 35-90 miles in
the rural West. On an annual aver-
age basis, natural visibility condi-
tions have been estimated at ap-
proximately 80-90 miles in the East
and up to 140 miles in the West.5
Natural visibility 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 concentrations
in the East than in the West.
Figures 6-7a, 6-7b, and 6-7c
illustrate regional visibility impair-
ment in terms of reconstructed
aerosol light extinction based on
measurements at IMPROVE sites
between 1995 and 1997. Maps are
presented for the clearest, middle
and haziest 20 percent of the distri-
bution. The pie charts show the
relative contribution of different
particle constituents to visibility
impairment. Annual average aero-
sol 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 gener-
ally greater in the rural East com-
pared to most of the West. As not-
89 90 91 92 93 94 95 96 97
94 CHAPTER 6: VISIBILITY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table 6-1. Summary of Class I Area trend* analysis.
Parameter
Number of Sites With
Significant Upward
(Deteriorating) Trends
Number of Sites With
Significant Downward
(Improving) Trends
West
East
West
East
Deciviews, worst 20%
1
0
9
0
Deciviews, middle 20%
0
0
15
3
Deciviews, best 20%
0
0
11
2
Light extinction due to
sulfate, worst 20%
0
0
0
0
Light extinction due to
sulfate, middle 20%
0
0
0
3
Light extinction due to
sulfate, best 20%
1
0
2
0
Light extinction due to
organic carbon, worst 20%
0
0
15
1
Light extinction due to
organic carbon, middle 20%
0
0
24
5
Light extinction due to
organic carbon, best 20%
0
0
22
5
* Based on a total of 37 monitored sites with at least 6 years of data: 26 in the West, 11 in
the East.
ed earlier, sulfates account for more
than 60 percent of annual average
light extinction at most rural east-
ern sites. Sulfate plays a particular-
ly significant role in the humid
summer months due to its nature to
attract and dissolve in atmospheric
water vapor, most notably in the
Appalachian, northeast, and mid-
south regions. Nitrates, organic
carbon, and elemental carbon all
account for between 10-15 percent
of total light extinction in most
Eastern locations.
In the rural West, sulfates also
play a significant role, typically
accounting for about 25-40 percent
of total light extinction in most
regions. In several areas of the
West, however, Sulfates account for
over 50 percent of annual average
light extinction, including Mt Raini-
er, WA, Point Reyes, CA, Redwood
NP, CA, and the Cascades of Ore-
gon. Organic carbon typically
makes up 15-35 percent of total
light extinction in the rural West,
elemental carbon (absorption) ac-
counts for about 15-25 percent, and
soil dust (coarse PM) accounts for
about 10-20 percent. Nitrates typi-
cally account for less than 10 per-
cent of total light extinction in west-
ern locations, except in the southern
California region, where it accounts
for almost 40 percent.
Figures 6-8a, 6-8b, and 6-8c
illustrate current levels of visibility
impairment, in terms of deciviews,
for the clearest, middle, and haziest
20 percent days based on IMPROVE
data from 1995-1997? Note that the
deciview scale is more compressed
than the scale for visual range or
light extinction, with larger values
representing greater visibility deg-
radation. Most of the sites in the
intermountain West and Colorado
Plateau have annual average im-
pairment of 12 deciviews or less,
with the worst days ranging up to
16 deciviews. Several other western
sites in the northwest and Califor-
nia experience levels on the order of
15-25 deciviews on the haziest 20
percent of days. Many rural loca-
tions in the East have annual aver-
Table 6-2. Class I areas with potentially deteriorating visibility (based on trend in deci-
views).
Clearest 20% Days
Middle 20% Days
Haziest 20% Days
Brigatine Wilderness (NJ)
Dolly Sods wilderness (VW)
Lye Brook Wilderness (VT)
Okefenokee Wilderness (FL)
San Gorgonio Wilderness
(CA)
Lye Brook Wilderness (VT)
Upper Buffalo Wilderness
(AR)
Badlands NP (SD)
Bandelier National
Monument (NM)
Big Bend NP (TX)
Bryce Canyon NP (UT)
Great Smokies NP (TN)
Mammoth Cave NP
(KY)
Shenandoah NP (VA)
Sipsey Wilderness (AL)
CHAPTER 6: VISIBILITY 95
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 6-7a. Aerosol light extinction (in Mm-1) for the clearest 20% days and contribution by individual particulate matter constituents,
based on 1995-1997 IMPROVE data.
12.45
13.06
14.58
12.87
110.44
Species
Nitrate
Organic Carbon
Elemental Carbon
Crustal Matter
I | Sulfate
Figure 6-7b. Aerosol light extinction (in Mm-1) for the middle 20% days and contribution by individual particulate matter constituents,
based on 1995-1997 IMPROVE data.
37.97
198.70
24.46
26.30
Species
Nitrate
Organic Carbon
Elemental Carbon
Crustal Matter
I | Sulfate
96 CHAPTER 6: VISIBILITY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 6-7c. Aerosol light extinction (in Mm-1) for the haziest 20% days and contribution by individual particulate matter constituents,
based on 1995-1997 IMPROVE data.
133.41
Species
r I Nitrate
Organic Carbon
Elemental Carbon
Crustal Matter
| | Sulfate
Figure 6-8a. Current visibility impairment expressed in deciviews for the clearest 20% days based on 1995-1997 IMPROVE data.
Deciview ranges at
IMPROVE sites
o 7-10
O 10-13
O 13-16
9 16-18.73
CHAPTER 6: VISIBILITY 97
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 6-8b. Current visibility impairment expressed in deciviews for the middle 20% days based on 1995-1997 IMPROVE data.
Ol6.(
°9.43
Declvlew Ranges at
IMPROVE sites
O 10.01-13
O 13.01 -16
O 16.01 -19
0 19.01 -22
£ 22.01 - 25.23
Figure 6-8c. Current visibility impairment expressed in deciviews for the haziest 20% days based on 1995-1997 IMPROVE data.
° 14.00
13.17
'13.20
~eciview ranges at
IMPROVE sites
o 10.53-14
o 14.01-17
O 17.01-20
O 20.01 - 25
# 25.01 -31.9
98 CHAPTER 6: VISIBILITY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
age values exceeding 23 deciviews,
with average visibility levels on the
haziest days up to 33 deciviews.
Programs to Improve Visibility
In July 1997, EPA proposed a
new regional haze program to ad-
dress visibility impairment in na-
tional parks and wilderness areas
caused by numerous sources locat-
ed over broad regions. The pro-
posed program takes into consider-
ation scientific findings and policy
recommendations from a number of
sources, including the National
Academy of Sciences, the Grand
Canyon Visibility Transport Com-
mission, and a Federal Advisory
Committee on Ozone, Particulate
Matter, and Regional Haze Imple-
mentation Programs. The proposal
lays out a framework within which
states can conduct regional plan-
ning and develop implementation
plans which are to achieve "reason-
able progress" toward the national
visibility goal of no human-caused
impairment in the 156 mandatory
Class I federal areas across the
country. Because of the common
precursors and the regional nature
of the ozone, PM, and regional haze
problems, EPA is developing these
implementation programs together
to integrate future planning and
control strategy efforts to the great-
est extent possible. Implementation
of the PM and Ozone NAAQS in
conjunction with a future regional
haze program is expected to im-
prove visibility in urban as well as
rural areas across the country. Oth-
er air quality programs are expected
to lead to emissions reductions that
will improve visibility in certain
regions of the country. The acid
rain program will achieve signifi-
cant regional reductions in the
emissions of S02, which is expected
to reduce sulfate haze particularly
in the eastern United States. The
recent NOx State Implementation
Plan (SIP) call to reduce emissions
from sources of NOx to reduce
formation of ozone should also
improve regional visibility condi-
tions to some degree. In addition,
the NAAQS, mobile source, and
woodstove programs to reduce fuel
combustion and soot emissions can
benefit areas adversely impacted by
visibility impairment due to sources
of organic and elemental carbon.
References
1. Data from IMPROVE Visibility
Monitoring Network, 1998.
2. PhotoCD images provided by
Kristi Savig and John Molenar, Air
Resource Specialists, Inc., Fort Col-
lins, Colorado 80525.
3. Sisler, J. Spatial and Seasonal Pat-
terns and Long-Term Variability of the
Composition 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 Tempo-
ral Patterns and the Chemical Compo-
sition of the Haze in the United States:
An Analysis of Data from the IM-
PROVE Network, 1988-1991, Colo-
rado State University, Cooperative
Institute for Research in the Atmo-
sphere. Fort Collins, CO., 1993.
Also see (Submitted for publication)
James F. Sisler, and William C.
Malm, "Interpretation of Trends of
PM2.s and Reconstructed Visibility
from the IMPROVE Network,"
Journal of the Air and Waste Man-
agement Association, 1998.
4. R.B. Husar, J.B. Elkins, W.E.
Wilson, "U.S. Visibility Trends,
1906-1992," Air and Waste Manage-
ment Association 87th Annual
Meeting and Exhibition, Cincinnati,
OH, 1994.
5. Irving, Patricia M., ed., Acid Dep-
osition: State of Science and Technolo-
gy, Volume III, Terrestrial, Materi-
als, Health, and Visibility Effects,
The U.S. National Acid Precipita-
tion Assessment Program, Chapter
24, page 24-76.
6. See reference 1.
7. See reference 1.
CHAPTER 6: VISIBILITY 99
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
100 CHAPTER 6: VISIBILITY
-------
CHAPTER 7
Acid Deposition
http://www.epa.gov/oar/aqtrnd97/chapter7.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 matter
(sulfates and nitrates), S02/ N02/
nitric acid and when reacted with
volatile organic compounds (VOCs)
form ozone. The effects of atmo-
spheric deposition include acidifica-
tion of lakes and streams, nutrient
enrichment of coastal waters and
large river basins, soil nutrient deple-
tion and decline of sensitive forests,
agricultural crop damage, and im-
pacts on ecosystem biodiversity.
Toxic pollutants and metals also can
be transported and deposited through
atmospheric processes. (See Chapter
5: Air Toxics.)
Both local and long-range
emission 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 portion
ranges from 20 to 60 percent of total
deposition.
The United States Environmen-
tal Protection agency (EPA) is required
by several Congressional and other
mandates to assess the effectiveness
of air pollution control efforts. These
mandates include Title IX of the Clean
Air Act Amendments (CAAA), the
National Acid Precipitation Assess-
ment Program (NAPAP), the Govern-
ment Performance and Results Act,
and the U.S. Canada Air Quality
Agreement. One measure of effective-
ness of these efforts is whether sus-
tained 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. Nu-
merous years of continuous and con-
sistent data are required to overcome
this variability, making long-term
monitoring networks especially critical
for characterizing deposition levels
and identifying relationships among
emissions, atmospheric loadings, and
effects on human health and the envi-
ronment.
For wet and dry deposition,
these studies typically include mea-
surement of concentration levels of
key chemical components as well as
precipitation amounts. For dry depo-
sition, analyses also must include
meteorological measurements that
are used to estimate rate of the actual
deposition, or "flux." Data representing
total deposition loadings (e.g., total
sulfate or nitrate) are what many envi-
ronmental 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), described in detail below,
were developed to monitor wet and
dry acid deposition, respectively.
Monitoring site locations are pre-
dominantly rural by design to assess
the relationship between regional
pollution and changes in regional
patterns in deposition. CASTNet also
includes measurements of rural
ozone and the chemical constituents
of PM2 5. Rural monitoring sites of
NADP and CASTNet provide data
where sensitive ecosystems are lo-
cated and provide insight into natural
background levels of pollutants
where urban influences are minimal.
These data provide needed informa-
tion to scientists and policy analysts
to study and evaluate numerous
environmental effects, particularly
those caused by regional sources of
emissions for which long range trans-
CHAPTER 7: ACID DEPOSITION 101
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 7-1. The NADP/NTN Network.
/
0
e
e
V
/
g«
Oqq
port plays an important role. Mea-
surements from these networks are
also important for understanding
non-ecological impacts of air pollu-
tion such as visibility impairment
and damage to materials, particu-
larly those of cultural and historical
importance.
National A tmospheric Deposition
Network
The NADP was initiated in the late
1970s as a cooperative program be-
tween federal and state agencies,
universities, electric utilities, and other
industries to determine geographical
patterns and trends in precipitation
chemistry in the United States. Col-
lection of weekly wet deposition
samples began in 1978. The size of
the NADP Network grew rapidly in the
early 1980s when the major research
effort by the NAPAP called for charac-
terization of acid deposition 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 today as the longest running
national deposition monitoring net-
work (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 eco-
logical 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 conducted by the NADP's
Central Analytical Lab at the Illinois
State Water Survey. A new subnet-
work of the NADP, the Mercury Deposi-
tion Network (MDN) measures mer-
cury in precipitation. The MDN is
discussed in Chapter 5 of this report.
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 sul-
fates are similar to changes in S02
emissions. In 1995, however, con-
centrations of sulfates in precipita-
tion over a large area of the Eastern
United States exhibited a dramatic
and unprecedented reduction.2 In
1995 and continued in 1996, sul-
fates have been estimated to be 10-
25 percent lower than levels ex-
pected with a continuation of
1983-1994 trends (see Figure 7-2).
This important reduction in acid pre-
cipitation is directly related to the
large regional decreases in S02 emis-
102 CHAPTER 7: ACID DEPOSITION
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
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 S02
emission increases at some Phase II
emissions sources that will not be
controlled by the acid rain program
until the year 2000.
sions resulting from Phase I of the
acid rain program (see the SO; sec-
tion in Chapter 2). The largest re-
ductions in sulfate concentrations
occurred along the Ohio River Val-
ley and in states immediately down-
wind of this region. For example,
the average reduction in sulfate
concentrations in Ohio was approxi-
mately 21 percent, in Maryland, 27
percent, and in Pennsylvania, 15 per-
cent. The largest decrease (32 per-
cent) occurred in the northern portion
of West Virginia. Reductions in hydro-
gen ion concentrations (H+) 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.3
Analyses based on the 1997 data are
not yet available.
The dense network of NADP/
NTN sites facilitate the development
of concentration and wet deposition
maps to describe the trends and
spatial patterns in the constituents
of acid precipitation. Figures 7-3
and 7-4 show sulfate and nitrate
concentrations in precipitation lev-
els for 1997. Sulfate concentrations
in precipitation are highest in the
Great Lake States and areas extend-
ing eastward. Nitrates in precipita-
tion are more regionally uniform.
The highest nitrate levels in precipi-
tation are in the vicinity of the Great
Lakes, with relatively high concen-
trations extending from the Plains
States to the Northeast.
Reported concentrations and
total wet deposition are both depen-
dent on the amount of precipitation in
a particular year. While larger
amounts of precipitation can dilute
the measured pollutant concentration,
it also can contribute to higher lev-
els of wet deposition. Figures 7-5
and 7-6 present estimates for total
wet deposition of sulfates and ni-
trates respectively, by multiplying
concentration by the total amount of
precipitation. During 1997, the
highest sulfate wet deposition oc-
curred in western New York State
extending southward through the
Ohio Valley and along the Appala-
chian ridge. Nitrate deposition
shows a similar pattern.
Clean Air Status and Trends
Network
The CASTNet provides atmospheric
data on the dry deposition compo-
nent of total acid deposition, ground-
level ozone and other forms of atmos-
pheric pollution. CASTNet is
considered the nation's primary
source for atmospheric data to esti-
mate dry acidic deposition and to
CHAPTER 7: ACID DEPOSITION 103
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 7-3. Sulfate concentration in precipitation, 1997.
•i.cpi.o
Figure 7-4. Nitrate concentration in precipitation, 1997.
104 CHAPTER 7: ACID DEPOSITION
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 7-5, Wet deposition of sulfate, 1997.
SO4*
(kg/ha)
Figure 7-6. Wet deposition of nitrate, 1997.
NO,"
(kg/ha)
CHAPTER 7: ACID DEPOSITION 105
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 7-7, The CASTNet Network.
V _ < Q
VI \hr
of*'- ® '
1 . ¦¦¦ • . .V •. •
. «..vy
* ° ° 8 * 8 6 ° ft ° • VJ
e . . \ ° Bee • • . |
w \f « — —^-*>3""" y
v« / f ) t 2^ ® ^ e
V o * /
v r^v .C
\ f \)
provide data on rural ozone levels.
Used in conjunction with other na-
tional monitoring networks,
CASTNet is used to determine the
effectiveness of national emission
control programs. Established in
1987, CASTNet now comprises 72
monitoring stations across the United
States, as shown in Figure 7-7. 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, 19 stations are operated by
the National Park Service in coopera-
tion with EPA. Of the total number of
sites, 67 measure dry-deposition; 18
measure wet-deposition; 68 measure
ozone; and 8 measure aerosols for
visibility assessment.
Each CASTNet dry deposition
station measures:
• weekly average atmospheric
concentrations of sulfate, nitrate,
ammonium, sulfur dioxide, and
nitric acid.
• hourly concentrations of ambient
ozone levels.
• meteorological conditions required
for calculating dry deposition
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 collects wet deposition data at
the 18 sites where there are no
NADP/NTN stations within a 50 km
radius. Together, these two long-term
databases provide the necessary
data to estimate trends and spatial
patterns in total atmospheric deposi-
tion. National Oceanic and Atmo-
spheric Administration (NOAA) also
operates a smaller dry deposition
network called Atmospheric Inte-
grated Assessment Monitoring Net-
work (AlRMoN) focused on ad-
dressing research issues specifically
related to dry deposition measure-
ment.
Concentration Trends Analysis at
CASTNet Sites
CASTNet data were analyzed for the
period 1989-1995. During this 7-year
period, atmospheric concentrations of
sulfur dioxide and sulfate at 34 east-
ern CASTNet sites showed statisti-
cally-significant declining trends.
The average reduction in sulfur diox-
ide concentrations for all sites was 35
106 CHAPTER 7: ACID DEPOSITION
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure 7-8. Trends in annual mean aerosol sulfate concentrations atWhiteface
Mountain and Mayville, 1978-1996.
c
o
o
u
E
«b
$
V)
a>
3.
<3
w
11
9
7
5
Midwest emissions
D ~
"On-Qn d-Q
Mayville
°oRD
o
o
o©
Db
Oo' "°°OG. 0
0°-^
Whiteface Mt Q.
1
1978 1961 1984 1987 1990 1993 1996
Also shown are annual S02 emissions for the Midwest as explained in the text. Lines
through the points are the result of multiple regression and smoothing and are only
added to aid the eye.
percent and in sulfate concentra-
tions was 26 percent. Trends in
total nitrate concentrations (nitrates
plus nitric acid) were not as pro-
nounced, with an average reduction
of 8 percent. A regional estimate for
a cluster of sites in the Ohio River
Valley showed a close correspon-
dence between declining sulfur
dioxide concentration (35 percent)
and declining sulfur dioxide emis-
sions (32 percent) in this region.4
The relationship between re-
gional SOo emissions and sulfate air
quality is graphically illustrated in
Figure 7-8. This recently published
graph compares long-term trends
(1978-1996) in annual mean aerosol
sulfate concentrations at two rural
locations in New York State with up-
wind SO2 emissions for the Midwest
region (MN, WI, IL, MI, IN, OH, WV, KY
and Western PA). Although average
air quality fluctuates from year to
year, the underlying trend in annual
sulfate concentrations tracks emis-
sions with both trends exhibiting a
small decrease. Then, sulfates de-
clined sharply in 1995, correspond-
ing to a 36 percent reduction in re-
gional emissions. During 1995,
emissions from this region ac-
counted for 38 percent of the na-
tional emission inventory. The air
quality improvement (~1 ng/m3) was
approximately 30 percent for Mayville
and an impressive 47 percent for the
more distant Whiteface Mountain
location.4
Rural Ozone
Ozone data collected by CASTNet
are complementary to the larger
ozone data sets gathered by the
State and Local Air Monitoring Sta-
tions (SLAMS) and National Air
Monitoring Stations (NAMS) net-
works. Most air quality samples at
SLAMS/NAMS sites are located in
urban areas, while CASTNet sites
are in rural locations. Hourly ozone
measurements are taken at each of
the 50 sites operated by EPA. Data
from these sites provide information
to help characterize ozone transport
issues and ozone exposure levels.
Future trend reports will present
information on rural O3 concentra-
tions measured at CASTNet sites.
References
1. Lynch, J.A., Grim, J.W., and
Bowersox,V.C. 1995 Trends in
Precipitation Chemistry in the United
States: A National Perspective, 1980-
1992. Atmospheric Environment Vol
29, No. 11.
2. Lynch, J.A., Bowersox,V.C., and
Grim, J.W. 1996. Trends in Precipita-
tion Chemistry in the United States:
An Analysis of the Effects in 1995 of
Phase I of the Clean Air Act Amend
ments of 1990, Title IV. U.S. Geologi
cal Survey. Open-file Report 96-0346.
3. Lynch, J. A., Bowersox,V.C., and Grim,
J.W. Acid Rain Reduced in Eastern U.S.A.
Submitted to Environmental Science
Technology. In Review.
4. Holland, D. M., Principe, P., and
Sickles, J.E., II. Trends in Atmospher-
ic Concentration of Sulfur and Nitro-
gen Species in the Eastern United
States. Atmospheric Environment, Vol.
33, 37-49
5. Husain, L., Dutkiewicz, V.A., and
Dass, M. 1998. Evidence for Decrease
in Atmospheric Sulfer Burden in the
Eastern United States Caused by Re-
duction in SO., Emissions. Geophysical
Research Letters Vol. 25 No. 7.
CHAPTER 7: ACID DEPOSITION 107
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
108 CHAPTER 7: ACID DEPOSITION
-------
APPENDIX A
Data Tables
http://www.epa.gov/oar/aqtrnd97/appenda.pdf
APPENDIX A: DATA TABLES 109
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-1. National Air Quality Trends Statistics for Criteria Pollutants, 1988-1997
Statistic
# of Sites Units Percentile 1988
1989 1990
1991 1992 1993 1994
1995 1996 1997
Carbon Monoxide
2nd Max. 8 hr.
368
ppm
95th
11.1
11.1
10.6
9.9
8.5
8.0
8.1
7.6
7.4
6.8
2nd Max. 8 hr.
368
ppm
90th
10.2
9.8
00
00
00
00
7.8
7.2
7.6
6.7
6.5
6.0
2nd Max. 8 hr.
368
ppm
75th
7.7
7.8
7.1
7.0
6.4
5.9
6.2
5.5
5.1
4.9
2nd Max. 8 hr.
368
ppm
50th
6.0
5.9
5.4
5.2
4.8
4.7
4.9
4.2
3.9
3.8
2nd Max. 8 hr.
368
PPm
25th
4.3
4.4
4.2
3.9
3.7
3.6
3.8
3.2
3.0
2.8
2nd Max. 8 hr.
368
PPm
10th
3.4
3.4
3.1
3.0
2.8
2.9
2.8
2.5
2.3
2.1
2nd Max. 8 hr.
368
PPm
5th
2.8
2.8
2.5
2.3
2.3
2.2
2.2
2.3
2.0
1.8
2nd Max. 8 hr.
368
PPm
Arith. Mean
6.3
6.3
5.8
5.6
5.1
4.9
5.0
4.5
4.2
3.9
Lead
Max. Qtr. AM
195
PPm
95th
0.37
0.27
0.29
0.20
0.18
0.17
0.14
0.12
0.12
0.12
Max. Qtr. AM
195
PPm
90th
0.22
0.16
0.16
0.15
0.13
0.10
0.09
0.08
0.08
0.08
Max. Qtr. AM
195
PPm
75th
0.13
0.11
0.09
0.07
0.06
0.06
0.05
0.05
0.04
0.04
Max. Qtr. AM
195
PPm
50th
0.08
0.06
0.05
0.04
0.03
0.03
0.03
0.03
0.03
0.02
Max. Qtr. AM
195
PPm
25th
0.04
0.04
0.03
0.03
0.02
0.02
0.02
0.02
0.01
0.01
Max. Qtr. AM
195
PPm
10th
0.03
0.03
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.01
Max. Qtr. AM
195
PPm
5th
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.00
0.01
Max. Qtr. AM
195
PPm
Arith. Mean
0.12
0.09
0.09
0.07
0.06
0.05
0.05
0.04
0.04
0.04
Nitrogen Dioxide
Arith. Mean
224
PPm
95th
0.044
0.043
0.040
0.043
0.038
0.036
0.040
0.039
0.037
0.034
Arith. Mean
224
PPm
90th
0.036
0.035
0.034
0.033
0.032
0.032
0.032
0.031
0.031
0.029
Arith. Mean
224
PPm
75th
0.027
0.027
0.025
0.025
0.024
0.024
0.025
0.023
0.024
0.023
Arith. Mean
224
PPm
50th
0.020
0.020
0.019
0.019
0.018
0.018
0.019
0.018
0.018
0.018
Arith. Mean
224
PPm
25th
0.014
0.013
0.012
0.012
0.012
0.012
0.012
0.012
0.012
0.011
Arith. Mean
224
PPm
10th
0.007
0.007
0.007
0.007
0.007
0.006
0.007
0.006
0.007
0.006
Arith. Mean
224
PPm
5th
0.005
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.004
Arith. Mean
224
PPm
Arith. Mean
0.021
0.021
0.020
0.020
0.019
0.019
0.020
0.019
0.018
0.018
Ozone
2nd
Max. 1-hr
660
PPm
95th
0.200
0.177
0.170
0.170
0.160
0.156
0.151
0.152
0.144
0.144
2nd
Max. 1-hr
660
PPm
90th
0.178
0.150
0.147
0.150
0.131
0.138
0.132
0.139
0.127
0.131
2nd
Max. 1-hr
660
PPm
75th
0.147
0.124
0.120
0.123
0.112
0.120
0.117
0.123
0.115
0.116
2nd
Max. 1-hr
660
PPm
50th
0.124
0.106
0.107
0.107
0.099
0.104
0.104
0.110
0.103
0.103
2nd
Max. 1-hr
660
PPm
25th
0.105
0.095
0.095
0.095
0.090
0.091
0.092
0.098
0.092
0.090
2nd
Max. 1-hr
660
PPm
10th
0.090
0.085
0.083
0.081
0.082
0.080
0.082
0.085
0.083
0.080
2nd
Max. 1-hr
660
PPm
5th
0.082
0.080
0.074
0.075
0.075
0.074
0.076
0.077
0.077
0.075
2nd
Max. 1-hr
660
PPm
Arith. Mean
0.130
0.114
0.112
0.113
0.105
0.108
0.107
0.112
0.105
0.105
4th
Max.
8-hr
660
PPm
95th
0.136
0.119
0.117
0.116
0.107
0.110
0.107
0.113
0.103
0.105
4th
Max.
8-hr
660
PPm
90th
0.126
0.105
0.106
0.110
0.097
0.101
0.099
0.107
0.097
0.101
4th
Max.
8-hr
660
PPm
75th
0.112
0.093
0.094
0.097
0.087
0.091
0.091
0.096
0.090
0.091
4th
Max.
8-hr
660
PPm
50th
0.098
0.083
0.083
0.085
0.079
0.081
0.082
0.088
0.083
0.082
4th
Max.
8-hr
660
PPm
25th
0.082
0.075
0.075
0.073
0.073
0.073
0.074
0.077
0.075
0.073
4th
Max.
8-hr
660
PPm
10th
0.072
0.068
0.066
0.065
0.066
0.063
0.067
0.067
0.067
0.065
4th
Max.
8-hr
660
PPm
5th
0.065
0.061
0.060
0.059
0.061
0.058
0.060
0.060
0.062
0.059
4th
Max.
8-hr
660
PPm
Arith. Mean
0.098
0.086
0.085
0.087
0.082
0.082
0.083
0.087
0.083
0.082
110 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-1. National Air Quality Trends Statistics for Criteria Pollutants, 1988-1997 (continued)
Statistic
# of Sites Units Percentile 1988
1989
1990
1991 1992
1993
1994 1995 1996 1997
PM„
Annual Avg.
845
|jg/m3
95th
52.2
52.3
46.0
45.9
42.0
41.5
39.5
39.3
38.2
37.8
Annual Avg.
845
|jg/m3
90th
43.9
43.9
39.6
39.4
36.4
36.5
36.7
35.0
33.7
33.0
Annual Avg.
845
|jg/m3
75th
37.6
36.8
34.4
33.5
31.3
30.3
30.7
29.3
27.9
27.6
Annual Avg.
845
|jg/m3
50th
30.9
30.3
28.2
28.2
25.8
25.5
25.6
24.4
23.3
23.2
Annual Avg.
845
|jg/m3
25th
25.9
25.5
23.4
23.6
22.0
21.0
21.1
20.0
19.4
19.5
Annual Avg.
845
|jg/m3
10th
20.6
20.5
19.0
18.4
17.8
16.8
16.8
15.8
16.1
15.8
Annual Avg.
845
|jg/m3
5th
17.5
17.5
16.2
15.1
14.2
13.5
13.2
12.7
13.2
12.6
Annual Avg.
845
|jg/m3
Arith. Mean
32.4
32.1
29.5
29.2
26.9
26.2
26.2
25.1
24.2
24.0
99th Pctile
845
|jg/m3
95th
165.0
167.0
154.0
154.0
136.0
126.0
123
124.0
115.0
111.0
99th Pctile
845
|jg/m3
90th
129.0
131.0
124.0
127.0
110.0
107.0
108
103.0
96.0
95.0
99th Pctile
845
|jg/m3
75th
98.0
96.0
95.0
91.0
84.0
83.0
86
77.0
77.0
76.0
99th Pctile
845
|jg/m3
50th
77.0
77.0
75.0
72.0
66.0
67.0
65
64.0
61.0
59.0
99th Pctile
845
|jg/m3
25th
59.0
60.0
59.0
58.0
55.0
56.0
52
52.0
50.0
48.0
99th Pctile
845
|jg/m3
10th
45.0
48.0
48.0
48.0
45.0
44.0
42
41.0
40.0
39.0
99th Pctile
845
|jg/m3
5th
36.0
41.0
43.0
43.0
38.0
37.0
37
36.0
35.0
33.0
99th Pctile
845
|jg/m3
Arith. Mean
85.8
88.6
85.3
82.1
74.5
73.6
71
69.8
66.2
64.2
Sulfur Dioxide
Arith. Mean
486
ppm
95th
0.0195
0.0182
0.0165
0.0161
0.0154
0.0153
0.0138
0.0115
0.0113
0.0106
Arith. Mean
486
ppm
90th
0.0154
0.0152
0.0144
0.0136
0.0128
0.0125
0.0122
0.0100
0.0097
0.0089
Arith. Mean
486
ppm
75th
0.0118
0.0115
0.0107
0.0099
0.0095
0.0093
0.0090
0.0074
0.0073
0.0070
Arith. Mean
486
ppm
50th
0.0082
0.0080
0.0076
0.0076
0.0068
0.0067
0.0065
0.0051
0.0053
0.0051
Arith. Mean
486
PPm
25th
0.0051
0.0049
0.0044
0.0046
0.0042
0.0039
0.0037
0.0033
0.0033
0.0031
Arith. Mean
486
PPm
10th
0.0023
0.0024
0.0022
0.0022
0.0020
0.0023
0.0021
0.0018
0.0019
0.0019
Arith. Mean
486
PPm
5th
0.0017
0.0016
0.0015
0.0015
0.0014
0.0015
0.0015
0.0014
0.0014
0.0014
Arith. Mean
486
PPm
Arith. Mean
0.0089
0.0087
0.0081
0.0079
0.0073
0.0072
0.0069
0.0056
0.0056
0.0054
2nd
Max. 24-hr
487
PPm
95th
0.0960
0.0960
0.0850
0.0720
0.074
0.0720
0.0720
0.0570
0.0600
0.0520
2nd
Max. 24-hr
487
PPm
90th
0.0740
0.0760
0.0660
0.0610
0.061
0.0580
0.0620
0.0480
0.0470
0.0440
2nd
Max. 24-hr
487
PPm
75th
0.0560
0.0530
0.0500
0.0450
0.044
0.0420
0.0450
0.0330
0.0330
0.0330
2nd
Max. 24-hr
487
PPm
50th
0.0390
0.0390
0.0340
0.0320
0.031
0.0280
0.0330
0.0220
0.0230
0.0230
2nd
Max. 24-hr
487
PPm
25th
0.0250
0.0240
0.0210
0.0210
0.019
0.0190
0.0190
0.0160
0.0150
0.0140
2nd
Max. 24-hr
487
PPm
10th
0.0120
0.0120
0.0100
0.0100
0.010
0.0100
0.0090
0.0080
0.0090
0.0080
2nd
Max. 24-hr
487
PPm
5th
0.0070
0.0070
0.0060
0.0070
0.006
0.0055
0.0050
0.0050
0.0050
0.0050
2nd
Max. 24-hr
487
PPm
Arith. Mean
0.0437
0.0419
0.0382
0.0352
0.034
0.0329
0.0343
0.0261
0.0266
0.0253
APPENDIX A: DATA TABLES 111
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-2. National Carbon Monoxide Emissions Estimates, 1988-1997 (thousand short tons)
Source Category
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
FUEL COMBUSTION
7,373
7,443
5,510
5,856
6,154
5,585
5,519
5,934
5,980
4,817
Electric Utilities
314
321
363
349
350
362
370
372
394
406
Coal
230
233
234
234
236
246
247
250
248
254
Oil
25
26
20
19
15
16
15
10
11
12
Gas
48
51
51
51
51
49
53
55
76
79
Internal Combustion
11
11
57
45
47
51
55
58
59
62
Industrial
669
672
879
920
955
1,043
1,041
1,056
1,072
1,110
Coal
87
87
105
101
102
101
100
98
99
100
Oil
46
46
74
60
64
66
66
71
72
73
Gas
265
271
226
284
300
322
337
345
348
362
Other
173
173
279
267
264
286
287
297
306
318
Internal Combustion
98
96
195
208
227
268
251
245
247
257
Other
6,390
6,450
4,268
4,587
4,849
4,180
4,108
4,506
4,513
3,301
Residential Wood
6,086
6,161
3,781
4,090
4,332
3,679
3,607
3,999
3,993
2,778
Other
303
288
488
497
517
502
502
506
520
522
INDUSTRIAL PROCESSES
7,034
7,013
5,852
5,740
5,683
5,898
5,839
5,791
5,816
6,052
Chemical & Allied Processing
1,917
1,925
1,183
1,127
1,112
1,093
1,171
1,223
1,222
1,287
Metals Processing
2,101
2,132
2,640
2,571
2,496
2,536
2,475
2,380
2,378
2,465
Petroleum & Related Industries
441
436
332
345
371
371
338
348
348
364
Other Industrial Processes
711
716
537
548
544
594
600
624
635
663
Solvent Utilization
2
2
5
5
5
5
5
6
5
6
Storage & Transport
56
55
76
28
17
51
24
25
25
26
Waste Disposal & Recycling
1,806
1,747
1,079
1,116
1,138
1,248
1,225
1,185
1,203
1,242
TRANSPORTATION
85,779
80,870
73,224
77,443
75,511
76,030
77,883
70,377
69,353
67,014
On-Road Vehicles
71,081
66,050
57,848
62,074
59,859
60,202
61,833
54,106
52,944
50,257
Non-Road Sources
14,698
14,820
15,376
15,368
15,652
15,828
16,050
16,271
16,409
16,755
MISCELLANEOUS
15,895
8,154
11,208
8,751
7,052
7,013
9,613
7,049
9,462
9,568
Fires
15,895
8,154
11,176
8,724
7,022
6,979
9,585
7,021
9,435
9,540
Other
NA
NA
32
28
30
34
28
28
27
28
TOTAL ALL SOURCES
116,081
103,480
95,794
97,790
94,400
94,526
98,854
89,151
90,611
87,451
Note: Some columns may not sum to totals due to rounding.
112 APPENDIX A: DATA TABLES
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-3. National Lead Emissions Estimates, 1988-1997 (shorttons)
Source Cateaorv
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
FUEL COMBUSTION
511
505
500
495
490
495
494
488
493
496
Electric Utilities
66
67
64
61
59
61
61
57
61
64
Coal
46
46
46
46
47
49
49
50
52
53
Oil
20
21
18
15
12
12
12
7
8
11
Industrial
19
18
18
18
17
19
18
17
16
17
Coal
14
14
14
15
14
14
14
14
13
13
Oil
5
4
4
3
3
5
4
3
3
4
Other
426
420
418
416
414
415
415
414
416
415
Commercial/Institutional Coal
5
4
4
3
3
4
3
4
5
5
Commercial/Institutional Oil
5
4
4
4
4
3
3
3
3
4
Misc. Fuel Comb, (except residential)
400
400
400
400
400
400
400
400
400
400
Residential Other
16
12
10
9
7
8
8
8
7
7
INDUSTRIAL PROCESSES
3,090
3,161
3,278
3,081
2,734
2,869
3,005
2,873
2,892
2,897
Chemical & Allied Processing
136
135
136
132
93
92
96
163
167
159
Metals Processing
1,965
2,088
2,169
1,975
1,773
1,899
2,027
2,048
2,052
2,038
Other Industrial Processes
172
173
169
167
56
54
53
58
51
54
Waste Disposal & Recycling
817
765
804
807
812
824
829
604
622
646
TRANSPORTATION
3,452
1,802
1,197
592
584
547
544
563
525
522
On-Road Vehicles
2,566
982
421
18
19
19
19
19
20
19
Non-Road Sources
886
820
776
574
565
528
525
544
505
503
TOTAL ALL SOURCES
7,053
5.468
4.975
4.168
3.808
3.911
4.043
3.924
3.910
3,915
Note: Some columns may not sum to totals due to rounding.
APPENDIX A: DATA TABLES 113
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-4. National Nitrogen Oxides Emissions Estimates, 1988-1997 (thousand short tons)
Source Category
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
FUEL COMBUSTION
10,472
10,538
10,895
10,779
10,928
11,111
11,015
10,828
10,519
10,724
Electric Utilities
6,544
6,593
6,663
6,519
6,504
6,651
6,565
6,385
6,060
6,178
Coal
5,666
5,676
5,642
5,559
5,579
5,744
5,636
5,579
5,542
5,588
Oil
272
285
221
212
170
180
163
96
103
131
Gas
556
582
565
580
579
551
591
562
264
286
Internal Combustion
50
49
235
168
175
176
175
148
151
159
Industrial
3,188
3,209
3,035
2,979
3,071
3,151
3,147
3,145
3,170
3,270
Coal
617
615
585
570
574
589
602
597
599
614
Oil
296
294
265
237
244
245
241
247
246
240
Gas
1,584
1,625
1,182
1,250
1,301
1,330
1,333
1,324
1,336
1,385
Other
121
120
131
129
126
124
124
123
125
130
Internal Combustion
569
556
874
793
825
863
846
854
864
902
Other
740
736
1,196
1,281
1,353
1,309
1,303
1,298
1,289
1,276
Commercial/Institutional Coal
38
38
40
36
38
40
40
38
38
40
Commercial/Institutional Oil
117
106
97
88
93
93
95
103
102
107
Commercial/Institutional Gas
157
159
200
210
225
232
237
231
234
241
Misc. Fuel Comb. (Except Residential)
11
11
34
32
28
31
31
30
29
30
Residential Wood
74
75
46
50
53
45
44
49
48
34
Residential Other
343
347
780
865
916
867
857
847
838
825
INDUSTRIAL PROCESSES
860
852
892
816
857
861
878
873
879
917
Chemical & Allied Processing
273
273
168
165
163
155
160
158
159
167
Metals Processing
82
83
97
76
81
83
91
98
98
102
Petroleum & Related Industries
100
97
153
121
148
123
117
110
110
115
Other Industrial Processes
315
311
378
352
361
370
389
399
403
421
Solvent Utilization
3
3
1
2
3
3
3
3
3
3
Storage & Transport
2
2
3
6
5
5
5
6
6
6
Waste Disposal & Recycling
85
84
91
95
96
123
114
99
100
103
TRANSPORTATION
11,659
11,731
11,278
11,639
11,750
11,849
12,069
11,830
11,650
11,595
On-Road Vehicles
7,661
7,682
7,041
7,374
7,440
7,510
7,672
7,323
7,171
7,035
Non-Road Sources
3,998
4,049
4,237
4,265
4,310
4,339
4,397
4,507
4,479
4,560
MISCELLANEOUS
727
293
371
286
254
225
383
237
343
346
TOTAL ALL SOURCES
23,718
23,414
23.436
23.520
23,789
24.046
24.345
23,768
23,391
23,582
Note: Some columns may not sum to totals due to rounding.
114 APPENDIX A: DATA TABLES
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-5. National Volatile Organic Compounds Emissions Estimates, 1988-1997 (thousand short tons)
Source Category
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
FUEL COMBUSTION
1,360
1,372
1,005
1,075
1,114
993
989
1,073
1,079
861
Electric Utilities
37
37
47
44
44
45
45
44
49
51
Coal
27
27
27
27
27
29
29
29
28
29
Oil
7
7
6
5
4
4
4
3
3
3
Gas
2
2
2
2
2
2
2
2
8
8
Internal Combustion
1
1
12
10
10
10
10
10
10
10
Industrial
136
134
182
196
187
186
196
206
208
217
Coal
7
7
7
6
7
6
8
6
6
6
Oil
16
16
12
11
12
12
12
12
12
12
Gas
61
61
58
60
52
51
63
73
73
77
Other
36
36
51
51
49
51
50
50
51
53
Internal Combustion
15
15
54
68
66
66
64
65
66
69
Other
1,188
1,200
776
835
884
762
748
823
822
593
Residential Wood
1,155
1,169
718
776
822
698
684
759
758
527
Other
33
31
58
59
62
64
63
64
64
9
INDUSTRIAL PROCESSES
10,853
10,755
10,000
10,178
10,380
10,578
10,738
10,780
9,482
9,836
Chemical & Allied Processing
982
980
634
710
715
701
691
660
436
458
Metals Processing
74
74
122
123
124
124
126
125
70
73
Petroleum & Related Industries
645
639
612
640
632
649
647
642
517
538
Other Industrial Processes
408
403
401
391
414
442
438
450
439
458
Solvent Utilization
5,945
5,964
5,750
5,782
5,901
6,016
6,162
6,183
6,273
6,483
Storage & Transport
1,842
1,753
1,495
1,532
1,583
1,600
1,629
1,652
1,312
1,377
Waste Disposal & Recycling
959
941
986
999
1,010
1,046
1,046
1,067
433
449
TRANSPORTATION
10,583
9,506
8,765
8,965
8,569
8,619
8,940
8,106
7,899
7,660
On-Road Vehicles
8,290
7,192
6,313
6,499
6,072
6,103
6,401
5,701
5,502
5,230
Non-Road Sources
2,293
2,314
2,452
2,466
2,498
2,516
2,538
2,405
2,397
2,430
MISCELLANEOUS
1,231
642
1,164
845
579
641
798
599
846
858
Other Combustion
1,230
641
1,064
756
485
535
710
511
761
770
Fires
1,230
641
1,061
753
482
532
707
508
758
767
Other
NA
NA
3
3
3
3
3
3
3
3
Other
1
1
100
89
94
105
88
88
85
87
TOTAL ALL SOURCES
24,027
22,274
20.935
21.063
20.642
20.830
21.465
20.558
19.306
19,214
Note: Some columns may not sum to totals due to rounding.
APPENDIX A: DATA TABLES 115
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
TableA-6. National PM10 Emissions Estimates, 1988-1997 (thousand short tons)
Source Category
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
FUEL COMBUSTION
1,381
1,382
1,196
1,147
1,184
1,124
1,113
1,179
1,192
1,101
Electric Utilities
276
271
295
257
257
279
273
268
288
290
Coal
261
255
265
232
234
253
246
244
264
265
Oil
11
12
9
10
7
9
8
5
5
6
Gas
1
1
1
1
0
1
1
1
0
0
Internal Combustion
3
3
20
15
16
17
17
18
18
19
Industrial
243
243
270
233
244
257
270
302
306
314
Coal
70
70
84
72
74
71
70
70
71
72
Oil
48
48
52
44
45
45
44
49
50
48
Gas
45
44
41
34
40
43
43
45
45
47
Other
79
78
87
72
74
86
74
73
75
78
Internal Combustion
3
3
6
10
11
12
38
64
65
68
Other
862
869
631
657
683
588
570
610
598
497
Residential Wood
807
817
501
535
558
464
446
484
472
368
Other
55
52
130
122
124
124
125
126
126
129
INDUSTRIAL PROCESSES
1,294
1,276
1,306
1,264
1,269
1,240
1,219
1,231
1,232
1,277
Chemical & Allied Processing
62
63
77
68
71
66
76
67
67
70
Metals Processing
208
211
214
251
250
181
184
212
211
220
Petroleum & Related Industries
60
58
55
43
43
38
38
40
40
41
Other Industrial Processes
601
591
583
520
506
501
495
511
510
530
Solvent Utilization
2
2
4
5
5
6
6
6
6
6
Storage & Transport
101
101
102
101
117
114
106
109
109
114
Waste Disposal & Recycling
259
251
271
276
278
334
313
287
290
296
TRANSPORTATION
852
849
831
841
835
806
802
751
733
734
On-Road Vehicles
369
367
336
349
343
321
320
293
274
268
Non-Road Sources
483
482
495
491
492
485
481
457
459
466
TOTAL ALL SOURCES
3,527
3,507
3,333
3,252
3,288
3,170
3,134
3,161
3,157
3,112
Table A-7. Miscellaneous and Natural Particulate Matter Emissions Estimates, 1988-1997 (thousand short tons)
Source Category
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
MISCELLANEOUS
39,445
37,461
24,420
24,122
23,866
24,197
25,462
22,453
24,715
25,152
Agriculture & Forestry
7,453
7,320
5,146
5,106
4,909
4,475
4,690
4,661
4,708
4,707
Other Combustion
1,704
912
1,203
941
785
768
1,048
778
1,004
1,015
Fires
1,645
853
1,158
896
739
722
1,002
732
978
989
Other
59
59
45
45
46
46
46
46
26
26
Cooling Towers
NA
NA
0
0
0
0
0
1
1
1
Fugitive Dust
30,287
29,229
18,069
18,076
18,171
18,954
19,722
17,013
19,002
19,430
Wind Erosion
0
0
1
1
1
1
1
1
1
1
UnpavedRoads
12,379
11,798
11,234
11,206
10,918
11,430
11,370
10,362
12,060
12,305
Paved Roads
5,900
5,769
2,248
2,399
2,423
2,462
2,538
2,409
2,390
2,515
Construction
11,662
11,269
4,249
4,092
4,460
4,651
5,245
3,654
3,950
4,022
Other
346
392
336
377
369
409
569
586
602
587
NAT. SOURCES (wind erosion)
18,110
12,101
2,092
2,077
2,227
509
2,160
1,146
5,316
5,316
TOTAL ALL SOURCES
57,555
49,562
26,512
26,199
26,093
24,706
27,622
23,599
30,031
30,468
Note: Some columns may not sum to totals due to rounding.
116 APPENDIX A: DATA TABLES
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-8. National Sulfur Dioxide Emissions Estimates, 1988-1997 (thousand short tons)
Source Category
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
FUEL COMBUSTION
19,758
19,923
20,290
19,795
19,492
19,244
18,886
16,229
16,814
17,260
Electric Utilities
15,987
16,215
15,909
15,784
15,416
15,189
14,889
12,080
12,632
13,082
Coal
15,221
15,404
15,220
15,087
14,824
14,527
14,313
11,603
12,137
12,529
Oil
734
779
639
652
546
612
522
413
436
486
Gas
1
1
1
1
1
1
1
9
2
4
Internal Combustion
31
30
49
45
46
49
53
55
57
61
Industrial
3,111
3,086
3,550
3,256
3,292
3,284
3,218
3,357
3,399
3,365
Coal
1,856
1,840
1,914
1,805
1,783
1,763
1,740
1,728
1,762
1,769
Oil
806
812
927
779
801
809
777
912
918
847
Gas
360
346
543
516
552
555
542
548
548
572
Other
83
82
158
142
140
140
141
147
147
153
Internal Combustion
6
6
9
14
16
17
19
23
23
24
Other
660
624
831
755
784
772
780
793
782
813
Commercial/Institutional Coal
172
169
212
184
190
193
192
200
200
206
Commercial/Institutional Ol
295
274
425
376
396
381
391
397
389
414
Commercial/Institutional Gas
2
2
7
7
7
8
8
8
8
8
Misc. Fuel Comb. (Except Residential)
1
1
6
6
6
6
6
5
5
6
Residential l/lbod
11
11
7
7
8
6
6
7
7
5
Residential Other
180
167
175
176
177
178
177
176
173
171
INDUSTRIAL PROCESSES
2,052
2,010
1,900
1,721
1,758
1,723
1,676
1,637
1,644
1,718
Chemical & Allied Processing
449
440
297
280
278
269
275
286
287
301
Metals Processing
707
695
726
612
615
603
562
530
530
552
Petroleum & Related Industries
443
429
430
378
416
383
379
369
368
385
Other Industrial Processes
411
405
399
396
396
392
398
403
409
427
Solvent Utilization
1
1
0
0
1
1
1
1
1
1
Storage & Transport
5
5
7
10
9
5
2
2
2
2
Waste Disposal & Recycling
36
36
42
44
44
71
60
47
48
50
TRANSPORTATION
1,317
1,364
1,476
1,528
1,558
1,499
1,301
1,313
1,366
1,380
On-Road Vehicles
553
570
542
570
578
517
301
304
340
320
Non-Road Sources
764
794
934
958
980
982
1,000
1,008
1,026
1,061
MISCELLANEOUS
27
11
12
11
10
9
15
9
13
13
TOTAL ALL SOURCES
23,154
23.308
23,678
23,057
22.819
22,478
21.880
19,189
19,836
20,371
Note: Some columns may not sum to totals due to rounding.
APPENDIX A: DATA TABLES 117
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-9. National Long-Term Air Quality Trends, 1978-1997
CO
Pb
no2
Ozone
PM10
so2
Year
2nd Max. 8-hr
Max. Qtr.
Arith. Mean
2nd Max. 1-hr
Wtd. Arith. Mean
Arith. Mean
ppm
[jg/m3
ppm
ppm
[jg/m3
ppm
1978-87
(208 sites)
(160 sites)
f93 sites)
(320 sites)
—
(343 sites)
1978
9.7
1.16
0.024
0.149
—
0.0120
1979
9.5
1.01
0.024
0.137
—
0.0118
1980
00
00
0.76
0.023
0.139
—
0.0108
1981
8.5
0.60
0.022
0.127
—
0.0103
1982
7.9
0.53
0.021
0.125
—
0.0095
1983
7.8
0.39
0.021
0.139
—
0.0092
1984
7.8
0.35
0.021
0.124
—
0.0094
1985
7.0
0.24
0.021
0.123
—
0.0087
1986
7.0
0.15
0.021
0.119
0.0086
1987
6.7
0.12
0.021
0.125
0.0084
1988-97
(368 sites)
(19S sites)
f224 sites)
(660 sites)
(845 sites)
(486 sites)
1988
6.3
0.12
0.021
0.130
32.4
0.0089
1989
6.3
0.09
0.021
0.114
32.1
0.0087
1990
5.8
0.09
0.020
0.112
29.5
0.0081
1991
5.6
0.07
0.020
0.113
29.2
0.0079
1992
5.1
0.06
0.019
0.105
26.9
0.0073
1993
4.9
0.05
0.019
0.108
26.2
0.0072
1994
5.0
0.05
0.020
0.107
26.2
0.0069
1995
4.5
0.04
0.019
0.112
25.1
0.0056
1996
4.2
0.04
0.018
0.105
24.2
0.0056
1997
3.9
0.04
0.018
0.105
24.0
0.0054
118 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-10. National Air Quality Trends by Monitoring Location, 1988-1997
Statistic # of Sites
Carbon Monoxide
2nd Max. 8 hr. 12
2nd Max. 8 hr. 145
2nd Max. 8 hr. 208
Lead
Max. Qtr. 4
Max. Qtr. 99
Max. Qtr. 90
Nitrogen Dioxide
Arith. Mean 46
Arith. Mean 96
Arith. Mean 80
Ozone
2nd Max. 1-hr 234
2nd Max. 1-hr 292
2nd Max. 1-hr 117
Wtd. Arith. Mean 112
Wtd. Arith. Mean 329
Wtd. Arith. Mean 385
Sulfur Dioxide
Arith. Mean
127
Arith. Mean
202
Arith. Mean
147
Units Location 1988
ppm Rural 3.0
ppm Suburban 6.0
ppm Urban 6.8
|jg/m3 Rural 0.08
|jg/m3 Suburban 0.09
|jg/m3 Urban 0.14
ppm Rural 0.009
ppm Suburban 0.023
ppm Urban 0.027
ppm Rural 0.120
ppm Suburban 0.138
ppm Urban 0.132
|jg/m3 Rural 25.6
|jg/m3 Suburban 33.4
|jg/m3 Urban 33.6
ppm Rural 0.0072
ppm Suburban 0.0095
ppm Urban 0.0099
1989 1990 1991
2.7
2.6
2.6
6.1
5.6
5.3
6.7
6.2
6.0
0.06 0.07 0.06
0.08 0.07 0.06
0.09 0.10 0.07
0.009 0.008 0.008
0.022 0.021 0.021
0.026 0.025 0.024
0.108 0.108 0.106
0.119 0.116 0.119
0.114 0.110 0.111
25.7 24.0 23.0
32.9 30.4 29.9
33.3 30.4 30.4
0.0071 0.0067 0.0066
0.0091 0.0085 0.0083
0.0097 0.0090 0.0086
1992 1993 1994
2.2
1.8
2.1
5.0
4.8
5.0
5.4
5.1
5.3
0.05 0.05 0.03
0.05 0.04 0.04
0.06 0.06 0.05
0.008 0.008 0.008
0.020 0.020 0.021
0.024 0.024 0.025
0.100 0.103 0.102
0.109 0.112 0.112
0.104 0.105 0.106
21.5 20.4 20.5
27.7 27.0 27.0
27.9 27.3 27.4
0.0063 0.0064 0.0060
0.0077 0.0075 0.0071
0.0078 0.0076 0.0075
1995 1996 1997
2.1
1.7
1.6
4.3
4.0
3.9
4.7
4.5
4.1
0.03 0.02 0.03
0.04 0.03 0.03
0.05 0.05 0.05
0.007 0.008 0.007
0.020 0.019 0.019
0.023 0.023 0.023
0.107 0.101 0.100
0.117 0.108 0.109
0.110 0.106 0.102
19.4 19.3 19.0
26.1 24.8 24.7
26.0 25.2 25.1
0.0052 0.0050 0.0048
0.0057 0.0058 0.0056
0.0059 0.0058 0.0056
APPENDIX A: DATA TABLES 119
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-11. National Air Quality Trends Statistics by EPA Region, 1988-1997
Statistic # of Sites
Units
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
Region 1
CO
2nd Max. 8-hr
16
ppm
6.2
5.9
6.2
5.7
5.8
4.9
6.1
5.4
4.9
4.2
Pb
Max. Qtr.
—
|jg/m3
—
—
—
—
—
—
—
—
—
—
no2
Arith. Mean
16
ppm
0.025
0.024
0.023
0.023
0.021
0.022
0.023
0.021
0.021
0.020
°3
2nd Max. 1-hr
37
ppm
0.150
0.121
0.119
0.130
0.110
0.118
0.115
0.117
0.102
0.1116
°3
4th Max. 8-hr
37
PPm
0.112
0.091
0.090
0.099
0.086
0.088
0.087
0.091
0.080
0.090
PM10
Wtd. Arith. Mean
71
|jg/m3
24.8
24.4
22.7
23.4
20.6
20.1
20.7
18.4
19.1
19.4
so2
Arith. Mean
50
PPm
0.0095
0.0090
0.0081
0.0079
0.0073
0.0070
0.0068
0.0053
0.0053
0.0051
Region 2
CO
2nd Max. 8-hr
26
PPm
6.3
6.3
5.6
5.6
5.0
4.6
5.3
4.6
4.0
3.6
Pb
Max. Qtr.
12
|jg/m3
0.10
0.07
0.06
0.05
0.04
0.05
0.05
0.04
0.04
0.05
no2
Arith. Mean
11
PPm
0.032
0.030
0.029
0.028
0.027
0.027
0.029
0.027
0.027
0.026
°3
2nd Max. 1-hr
31
PPm
0.154
0.118
0.124
0.127
0.110
0.111
0.108
0.117
0.105
0.113
°3
4th Max. 8-hr
31
PPm
0.119
0.093
0.096
0.103
0.085
0.089
0.087
0.096
0.083
0.093
PM10
Wtd. Arith. Mean
58
|jg/m3
30.6
30.4
27.7
28.2
25.3
25.5
26.1
23.4
24.3
24.9
so2
Arith. Mean
38
PPm
0.0112
0.0109
0.0098
0.0100
0.0092
0.0084
0.0086
0.0066
0.0067
0.0061
Region 3
CO
2nd Max. 8-hr
41
PPm
5.6
5.6
5.2
4.7
4.4
4.3
4.7
4.0
3.7
3.4
Pb
Max. Qtr.
24
|jg/m3
0.15
0.11
0.09
0.08
0.06
0.05
0.05
0.04
0.04
0.04
no2
Arith. Mean
33
PPm
0.023
0.022
0.022
0.022
0.021
0.021
0.022
0.020
0.021
0.020
°3
2nd Max. 1-hr
78
PPm
0.143
0.108
0.110
0.117
0.101
0.115
0.110
0.114
0.104
0.113
O3
4th Max. 8-hr
78
PPm
0.112
0.087
0.088
0.096
0.082
0.092
0.087
0.093
0.084
0.091
PM10
Wtd. Arith. Mean
64
|jg/m3
32.6
32.0
29.3
30.4
26.0
26.7
27.7
26.7
25.5
25.6
so2
Arith. Mean
64
PPm
0.0141
0.0136
0.0127
0.0120
0.0110
0.0112
0.0112
0.0084
0.0085
0.0088
Region 4
CO
2nd Max. 8-hr
55
PPm
5.6
6.0
5.3
4.9
4.9
5.0
4.6
4.3
3.8
4.0
Pb
Max. Qtr.
27
|jg/m3
0.07
0.06
0.04
0.03
0.04
0.03
0.03
0.03
0.02
0.03
no2
Arith. Mean
21
PPm
0.017
0.016
0.015
0.015
0.015
0.015
0.015
0.015
0.015
0.015
°3
2nd Max. 1-hr
111
PPm
0.116
0.100
0.106
0.098
0.096
0.105
0.100
0.105
0.102
0.103
°3
4th Max. 8-hr
110
PPm
0.092
0.079
0.084
0.076
0.077
0.082
0.081
0.083
0.082
0.083
PM10
Wtd. Arith. Mean
100
|jg/m3
32.5
31.1
31.0
29.5
27.5
26.8
26.4
26.0
24.5
24.9
so2
Arith. Mean
66
PPm
0.0068
0.0065
0.0063
0.0060
0.0057
0.0058
0.0053
0.0045
0.0046
0.0046
Region S
CO
2nd Max. 8-hr
44
PPm
5.6
5.7
5.1
4.9
4.5
4.4
5.2
4.1
3.3
3.1
Pb
Max. Qtr.
45
|jg/m3
0.17
0.12
0.16
0.09
0.09
0.08
0.08
0.06
0.06
0.06
no2
Arith. Mean
13
PPm
0.024
0.024
0.022
0.021
0.021
0.022
0.023
0.023
0.023
0.023
O3
2nd Max. 1-hr
126
PPm
0.128
0.107
0.101
0.111
0.097
0.097
0.105
0.111
0.102
0.101
O3
4th Max. 8-hr
126
PPm
0.101
0.085
0.082
0.089
0.079
0.077
0.084
0.089
0.085
0.083
PM,.
Wtd. Arith. Mean
145
|jg/m3
33.7
33.9
31.4
30.3
28.1
26.5
28.3
27.4
24.8
24.7
so2
Arith. Mean
124
PPm
0.0098
0.0098
0.0093
0.0091
0.0082
0.0083
0.0077
0.0061
0.0062
0.0059
120 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-11. National Air Quality Trends Statistics by EPA Region, 1988-1997 (continued)
Statistic # of Sites
Units
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
Region 6
CO
2nd Max. 8-hr
33
ppm
6.1
6.1
6.1
5.4
5.4
5.3
4.7
4.4
4.9
4.4
Pb
Max. Qtr.
25
|jg/m3
0.12
0.12
0.10
0.09
0.07
0.07
0.05
0.06
0.06
0.04
no2
Arith. Mean
21
ppm
0.017
0.015
0.015
0.014
0.016
0.014
0.016
0.016
0.015
0.015
°3
2nd Max. 1-hr
64
ppm
0.125
0.122
0.124
0.116
0.111
0.112
0.111
0.123
0.111
0.116
°3
4th Max. 8-hr
64
PPm
0.089
0.086
0.089
0.081
0.080
0.081
0.083
0.092
0.082
0.083
PM10
Wtd. Arith. Mean
92
|jg/m3
29.6
28.9
25.8
24.4
24.5
23.8
24.0
24.9
23.9
22.5
so2
Arith. Mean
34
PPm
0.0065
0.0064
0.0062
0.0059
0.0062
0.0053
0.0046
0.0046
0.0047
0.0043
Region 7
CO
2nd Max. 8-hr
23
PPm
5.1
5.2
4.9
5.0
4.3
4.2
4.1
3.9
4.0
3.7
Pb
Max. Qtr.
19
|jg/m3
0.07
0.05
0.03
0.03
0.02
0.02
0.01
0.01
0.02
0.04
no2
Arith. Mean
11
PPm
0.016
0.016
0.015
0.015
0.016
0.015
0.016
0.016
0.016
0.015
°3
2nd Max. 1-hr
30
PPm
0.111
0.092
0.089
0.091
0.091
0.088
0.096
0.101
0.093
0.094
°3
4th Max. 8-hr
30
PPm
0.087
0.073
0.069
0.074
0.074
0.066
0.077
0.081
0.075
0.075
PM10
Wtd. Arith. Mean
48
|jg/m3
33.1
32.8
29.7
28.9
28.2
27.0
27.8
26.9
27.4
25.6
so2
Arith. Mean
31
PPm
0.0084
0.0082
0.0075
0.0071
0.0062
0.0062
0.0063
0.0052
0.0049
0.0046
Region 8
CO
2nd Max. 8-hr
22
PPm
8.0
7.0
6.3
6.4
6.1
5.4
5.0
4.7
4.5
4.3
Pb
Max. Qtr.
7
|jg/m3
0.09
0.06
0.06
0.06
0.05
0.06
0.04
0.04
0.03
0.03
no2
Arith. Mean
17
PPm
0.014
0.013
0.013
0.013
0.013
0.013
0.014
0.013
0.013
0.013
°3
2nd Max. 1-hr
20
PPm
0.098
0.092
0.086
0.084
0.081
0.079
0.083
0.083
0.085
0.081
O3
4th Max. 8-hr
20
PPm
0.075
0.072
0.067
0.068
0.065
0.064
0.067
0.066
0.068
0.066
PM10
Wtd. Arith. Mean
101
|jg/m3
28.1
27.4
24.1
25.3
23.5
22.7
22.1
19.6
19.9
19.2
so2
Arith. Mean
33
PPm
0.0064
0.0058
0.0057
0.0054
0.0059
0.0057
0.0053
0.0048
0.0041
0.0036
Region 9
CO
2nd Max. 8-hr
93
PPm
7.0
6.9
6.4
6.3
5.4
4.9
5.3
4.7
4.5
4.2
Pb
Max. Qtr.
31
|jg/m3
0.10
0.08
0.07
0.06
0.03
0.04
0.03
0.03
0.03
0.03
no2
Arith. Mean
81
PPm
0.023
0.023
0.021
0.021
0.020
0.019
0.020
0.019
0.018
0.017
°3
2nd Max. 1-hr
150
PPm
0.138
0.139
0.127
0.126
0.124
0.120
0.117
0.118
0.114
0.102
°3
4th Max. 8-hr
150
PPm
0.098
0.096
0.090
0.091
0.090
0.088
0.087
0.087
0.086
0.078
PM10
Wtd. Arith. Mean
111
|jg/m3
40.3
41.8
38.1
36.9
32.8
31.8
30.6
30.6
28.7
29.0
so2
Arith. Mean
37
PPm
0.0033
0.0029
0.0025
0.0024
0.0025
0.0022
0.0021
0.0024
0.0023
0.0022
Region 10
CO
2nd Max. 8-hr
15
PPm
9.5
00
00
7.8
8.2
7.6
6.5
6.1
5.9
5.9
5.5
Pb
Max. Qtr.
5
|jg/m3
0.09
0.06
0.06
0.06
0.04
0.05
0.05
0.05
0.04
0.05
no2
Arith. Mean
—
PPm
—
—
—
—
—
—
—
—
—
—
O3
2nd Max. 1-hr
13
PPm
0.098
0.083
0.099
0.086
0.087
0.081
0.088
0.086
0.097
0.076
°3
4th Max. 8-hr
13
PPm
0.070
0.060
0.072
0.064
0.069
0.058
0.062
0.063
0.076
0.058
PM,.
Wtd. Arith. Mean
55
|jg/m3
35.8
34.4
31.2
32.3
30.5
30.6
26.9
23.6
23.5
24.0
so2
Arith. Mean
9
PPm
0.0069
0.0066
0.0071
0.0070
0.0073
0.0066
0.0066
0.0059
0.0051
0.0047
APPENDIX A: DATA TABLES 121
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997
CO Pb N02
°3
°3
PM10
PM10
so2
State
County
1990
8-hr QMax AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm) (Mg/m3) (ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
AL
CALHOUN CO
116,034
49
51
AL
CLAY CO
13,252
0.092
0.079
AL
COLBERT CO
51,666
41
44
0.020
AL
DE KALB CO
54,651
49
51
AL
ELMORE CO
49,210
0.087
0.070
AL
ESCAMBIA CO
35,518
51
55
AL
ETOWAH CO
99,840
58
63
AL
FRANKLIN CO
27,814
43
49
AL
GENEVA CO
23,647
0.084
0.073
AL
HOUSTON CO
81,331
50
58
AL
JACKSON CO
47,796
0.023
AL
JEFFERSON CO
651,525
6.1
0.122
0.088
111
111
0.018
AL
LAWRENCE CO
31,513
0.090
0.076
AL
LIMESTONE CO
54,135
35
40
AL
MADISON CO
238,912
3.1
0.096
0.086
48
50
AL
MARENGO CO
23,084
52
57
AL
MOBILE CO
378,643
0.117
0.081
142
166
0.049
AL
MONTGOMERY CO
209,085
1.2 0.0080
0.083
0.068
53
57
0.005
AL
MORGAN CO
100,043
48
55
AL
PIKE CO
27,595
0.62
48
51
AL
RUSSELL CO
46,860
55
68
AL
SHELBY CO
99,358
0.0100
0.115
0.084
67
71
AL
SUMTER CO
16,174
0.070
0.062
AL
TALLADEGA CO
74,107
67
70
AL
TUSCALOOSA CO
150,522
55
70
AL
WALKER CO
67,670
43
46
AK
ANCHORAGE BOROUGH
226,338
7.1
127
113
AK
FAIRBANKS N. STAR BOR.
77,720
12.1
59
59
AK
JUNEAU BOROUGH
26,751
90
90
AK
YUKON-KOYUKUK CA
8,478
0.057
0.051
AZ
COCHISE CO
97,624
0.070
0.065
74
77
AZ
COCONINO CO
96,591
0.076
0.072
AZ
GILA CO
40,216
68
158
AZ
GRAHAM CO
26,554
62
95
AZ
MARICOPA CO
2,122,101
7.8 0.03 0.0319
0.113
0.091
308
301
0.010
AZ
PIMA CO
666,880
4.4 0.01 0.0178
0.097
0.079
129
134
0.004
AZ
PINAL CO
116,379
0.024
AZ
SANTA CRUZ CO
29,676
93
126
AZ
YAVAPAI CO
107,714
27
33
AZ
YUMA CO
106,895
0.072
0.063
AR
ARKANSAS CO
21,653
67
81
AR
ASHLEY CO
24,319
63
93
AR
CRAIGHEAD CO
68,956
60
75
AR
CRITTENDEN CO
49,939
0.122
0.091
44
45
AR
GARLAND CO
73,397
44
80
AR
JEFFERSON CO
85,487
61
78
AR
MARION CO
12,001
31
60
AR
MILLER CO
38,467
64
78
AR
MONTGOMERY CO
7,841
0.077
0.068
AR
NEWTON CO
7,666
0.088
0.073
AR
OUACHITA CO
30,574
52
61
AR
PHILLIPS CO
28,838
47
59
AR
POPE CO
45,883
46
52
AR
PULASKI CO
349,660
4.7 0.0103
0.100
0.078
61
86
0.006
122 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
itate
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
AR
SEBASTIAN CO
99,590
59
68
AR
UNION CO
46,719
38
56
0.049
AR
WASHINGTON CO
113,409
36
54
AR
WHITE CO
54,676
55
77
CA
ALAMEDA CO
1,279,182
3.6
0.00
0.0198
0.111
0.072
55
65
CA
AMADOR CO
30,039
1.4
0.00
0.117
0.084
CA
BUTTE CO
182,120
4.5
0.00
0.0132
0.074
0.066
84
108
CA
CALAVERAS CO
31,998
1.0
0.118
0.085
34
112
CA
COLUSA CO
16,275
0.090
0.073
63
60
CA
CONTRA COSTA CO
803,732
3.1
0.01
0.0160
0.095
0.072
71
77
0.012
CA
DEL NORTE CO
23,460
46
58
CA
EL DORADO CO
125,995
3.6
0.0111
0.120
0.092
52
62
CA
FRESNO CO
667,490
7.1
0.00
0.0208
0.140
0.115
111
125
0.002
CA
GLENN CO
24,798
0.085
0.076
59
72
CA
HUMBOLDT CO
119,118
41
56
CA
IMPERIAL CO
109,303
16.7
0.03
0.0152
0.150
0.105
192
199
0.011
CA
INYO CO
18,281
0.084
0.077
256
402
CA
KERN CO
543,477
3.2
0.00
0.0244
0.141
0.105
96
137
0.005
CA
KINGS CO
101,469
0.0138
0.125
0.097
126
199
CA
LAKE CO
50,631
0.080
0.058
17
18
CA
LOS ANGELES CO
8,863,164
15.0
0.07
0.0432
0.168
0.120
93
116
0.010
CA
MADERA CO
88,090
0.085
CA
MARIN CO
230,096
2.6
0.0163
0.077
0.048
60
72
CA
MARIPOSA CO
14,302
0.111
0.093
39
62
CA
MENDOCINO CO
80,345
2.8
0.0101
0.067
0.054
50
66
CA
MERCED CO
178,403
0.0132
0.090
0.074
CA
MONO CO
9,956
3.3
0.083
0.077
99
112
CA
MONTEREY CO
355,660
1.7
0.0098
0.082
0.061
70
91
CA
NAPA CO
110,765
3.9
0.0121
0.075
0.055
71
78
CA
NEVADA CO
78,510
0.108
0.096
158
136
CA
ORANGE CO
2,410,556
5.7
0.0328
0.130
0.082
82
91
0.006
CA
PLACER CO
172,796
2.1
0.00
0.0152
0.112
0.085
39
50
CA
PLUMAS CO
19,739
0.071
0.061
66
66
CA
RIVERSIDE CO
1,170,413
5.1
0.05
0.0258
0.180
0.135
133
227
0.005
CA
SACRAMENTO CO
1,041,219
6.7
0.01
0.0190
0.136
0.091
104
108
0.006
CA
SAN BENITO CO
36,697
0.092
0.076
33
34
CA
SAN BERNARDINO CO
1,418,380
5.4
0.04
0.0362
0.171
0.127
133
208
0.005
CA
SAN DIEGO CO
2,498,016
4.9
0.03
0.0237
0.120
0.093
93
125
0.016
CA
SAN FRANCISCO CO
723,959
3.9
0.01
0.0200
0.067
0.042
65
81
0.006
CA
SAN JOAQUIN CO
480,628
3.9
0.00
0.0216
0.109
0.079
95
130
CA
SAN LUIS OBISPO CO
217,162
2.3
0.0127
0.085
0.070
68
75
0.026
CA
SAN MATEO CO
649,623
3.8
0.0184
0.079
0.053
65
70
CA
SANTA BARBARA CO
369,608
3.8
0.00
0.0193
0.108
0.081
63
122
0.005
CA
SANTA CLARA CO
1,497,577
5.6
0.01
0.0249
0.090
0.070
72
95
CA
SANTA CRUZ CO
229,734
0.7
0.0043
0.078
0.063
88
113
0.002
CA
SHASTA CO
147,036
0.108
0.087
56
63
CA
SIERRA CO
3,318
93
138
CA
SISKIYOU CO
43,531
0.070
0.059
30
32
CA
SOLANO CO
340,421
4.9
0.0130
0.101
0.071
63
85
0.005
CA
SONOMA CO
388,222
3.1
0.0131
0.100
0.081
55
85
CA
STANISLAUS CO
370,522
4.2
0.00
0.0208
0.113
0.089
115
119
CA
SUTTER CO
64,415
3.9
0.0140
0.096
0.074
83
98
CA
TEHAMA CO
49,625
0.090
0.076
52
58
CA
TRINITY CO
13,063
42
54
APPENDIX A: DATA TABLES 123
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
CA
TULARE CO
311,921
3.5
0.0188
0.117
0.101
86
96
CA
TUOLUMNE CO
48,456
1.9
0.107
0.086
CA
VENTURA CO
669,016
3.2
0.00
0.0199
0.128
0.105
136
253
0.011
CA
YOLO CO
141,092
1.5
0.0099
0.095
0.071
60
126
CO
ADAMS CO
265,038
4.3
0.03
0.0232
0.089
0.071
98
94
0.016
CO
ALAMOSA CO
13,617
113
93
CO
ARAPAHOE CO
391,511
2.8
0.082
0.065
CO
ARCHULETA CO
5,345
96
85
CO
BOULDER CO
225,339
5.4
0.092
0.072
42
43
CO
DELTA CO
20,980
78
90
CO
DENVER CO
467,610
6.4
0.03
0.0339
0.083
0.066
93
94
0.026
CO
DOUGLAS CO
60,391
0.094
0.075
54
54
CO
EL PASO CO
397,014
4.9
0.01
0.070
0.059
79
78
CO
FREMONT CO
32,273
37
41
CO
GARFIELD CO
29,974
36
45
CO
GUNNISON CO
10,273
215
203
CO
JEFFERSON CO
438,430
4.9
0.0094
0.095
0.076
70
70
CO
LAKE CO
6,007
0.03
CO
LA PLATA CO
32,284
106
106
CO
LARIMER CO
186,136
5.2
0.085
0.064
34
40
CO
MESA CO
93,145
5.4
49
48
CO
MONTEZUMA CO
18,672
0.068
CO
MONTROSE CO
24,423
55
65
CO
PITKIN CO
12,661
89
68
CO
PROWERS CO
13,347
98
66
CO
PUEBLO CO
123,051
56
88
CO
ROUTT CO
14,088
112
99
CO
SAN MIGUEL CO
3,653
80
75
CO
SUMMIT CO
12,881
75
95
CO
TELLER CO
12,468
121
120
CO
WELD CO
131,821
4.8
0.095
0.069
56
56
CT
FAIRFIELD CO
827,645
5.1
0.0226
0.142
0.109
65
90
0.031
CT
HARTFORD CO
851,783
5.9
0.0178
0.148
0.097
47
53
0.025
CT
LITCHFIELD CO
174,092
0.124
0.097
38
41
CT
MIDDLESEX CO
143,196
0.135
0.103
44
47
CT
NEW HAVEN CO
804,219
3.9
0.0236
0.145
0.109
64
63
0.032
CT
NEW LONDON CO
254,957
0.150
0.107
45
65
0.022
CT
TOLLAND CO
128,699
0.146
0.097
0.015
CT
WINDHAM CO
102,525
37
41
DE
KENT CO
110,993
0.124
0.099
DE
NEW CASTLE CO
441,946
4.5
0.0178
0.140
0.104
68
92
0.057
DE
SUSSEX CO
113,229
0.127
0.100
49
63
0.023
DC
FL
FL
WASHINGTON
ALACHUA CO
BAY CO
606,900
181,596
126,994
6.4
0.01
0.0246
0.128
0.091
0.096
47
41
52
49
75
62
0.022
FL
BREVARD CO
398,978
0.086
0.077
38
42
FL
BROWARD CO
1,255,488
4.8
0.04
0.0097
0.092
0.073
39
60
0.011
FL
COLLIER CO
152,099
37
46
FL
DADE CO
1,937,094
4.1
0.0166
0.106
0.075
52
71
0.004
FL
DUVAL CO
672,971
3.0
0.02
0.0143
0.116
0.087
50
56
0.015
FL
ESCAMBIA CO
262,798
0.110
0.086
56
57
0.033
FL
GULF CO
11,504
54
65
FL
HAMILTON CO
10,930
43
44
0.026
FL
HILLSBOROUGH CO
834,054
3.7
0.64
0.0096
0.112
0.086
87
92
0.038
124 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
FL
LAKE CO
152,104
43
39
FL
LEE CO
335,113
0.083
0.072
33
38
FL
LEON CO
192,493
0.056
43
43
FL
MANATEE CO
211,707
0.099
0.077
40
54
FL
MARTIN CO
100,900
32
40
FL
NASSAU CO
43,941
62
64
0.035
FL
ORANGE CO
677,491
4.3
0.0129
0.109
0.079
52
53
0.006
FL
OSCEOLA CO
107,728
0.088
0.075
FL
PALM BEACH CO
863,518
3.6
0.00
0.0120
0.086
0.068
39
67
0.013
FL
PASCO CO
281,131
0.092
0.079
FL
PINELLAS CO
851,659
3.7
0.00
0.0115
0.094
0.078
55
62
0.033
FL
POLK CO
405,382
0.102
0.079
0.017
FL
PUTNAM CO
65,070
44
44
0.014
FL
ST JOHNS CO
83,829
0.089
0.076
FL
ST LUCIE CO
150,171
0.082
0.067
35
35
FL
SARASOTA CO
277,776
5.3
0.105
0.079
56
52
0.012
FL
SEMINOLE CO
287,529
0.096
0.076
37
42
FL
VOLUSIA CO
370,712
0.088
0.073
38
40
GA
BARTOW CO
55,911
0.018
GA
BIBB CO
149,967
0.122
0.095
77
102
0.011
GA
CHATHAM CO
216,935
0.080
0.071
49
53
0.024
GA
CHATTOOGA CO
22,242
52
71
GA
DE KALB CO
545,837
4.3
0.34
0.0147
0.125
0.092
53
64
GA
DOUGHERTY CO
96,311
57
80
GA
DOUGLAS CO
71,120
0.103
GA
FANNIN CO
15,992
0.083
0.075
0.032
GA
FLOYD CO
81,251
61
71
0.016
GA
FULTON CO
648,951
3.7
0.02
0.0252
0.133
0.104
75
80
0.027
GA
GLYNN CO
62,496
0.091
0.079
55
58
GA
GWINNETT CO
352,910
0.105
0.086
GA
MUSCOGEE CO
179,278
0.81
0.098
0.081
64
127
GA
PAULDING CO
41,611
0.103
0.086
GA
RICHMOND CO
189,719
0.118
0.087
54
64
0.013
GA
ROCKDALE CO
54,091
0.0075
0.139
0.110
GA
SPALDING CO
54,457
55
59
GA
WALKER CO
58,340
57
57
GA
WASHINGTON CO
19,112
61
61
HI
HONOLULU CO
836,231
2.5
0.03
0.0046
0.053
0.047
28
29
0.007
HI
KAUAI CO
51,177
26
31
HI
MAUI CO
100,374
87
77
ID
ADA CO
205,775
4.7
0.0194
91
161
ID
BANNOCK CO
66,026
89
71
0.034
ID
BLAINE CO
13,552
52
58
ID
BONNER CO
26,622
73
73
ID
BONNEVILLE CO
72,207
56
79
ID
BUTTE CO
2,918
0.066
0.060
ID
CANYON CO
90,076
63
80
ID
CARIBOU CO
6,963
63
63
ID
KOOTENAI CO
69,795
67
91
ID
LEMHI CO
6,899
123
155
ID
LEWIS CO
3,516
62
83
ID
MADISON CO
23,674
43
46
ID
MINIDOKA CO
19,361
49
49
ID
NEZ PERCE CO
33,754
4.7
66
98
APPENDIX A: DATA TABLES 125
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
ID
POWER CO
7,086
346
259
ID
SHOSHONE CO
13,931
0.12
96
97
ID
TWIN FALLS CO
53,580
44
45
IL
ADAMS CO
66,090
0.078
0.068
40
43
0.024
IL
CHAMPAIGN CO
173,025
0.088
0.076
44
46
0.018
IL
COLES CO
51,644
43
44
IL
COOK CO
5,105,067
5.3
0.33
0.0336
0.113
0.094
99
114
0.041
IL
DU PAGE CO
781,666
0.04
0.088
0.072
58
59
0.018
IL
EFFINGHAM CO
31,704
0.095
0.077
IL
HAMILTON CO
8,499
0.089
0.074
IL
JACKSON CO
61,067
45
49
IL
JERSEY CO
20,539
0.096
0.082
IL
KANE CO
317,471
0.092
0.076
41
50
IL
LAKE CO
516,418
0.110
0.088
IL
LA SALLE CO
106,913
138
95
IL
MC HENRY CO
183,241
0.098
0.080
IL
MACON CO
117,206
0.03
0.087
0.077
46
56
0.021
IL
MACOUPIN CO
47,679
1.0
0.01
0.101
0.076
38
44
0.016
IL
MADISON CO
249,238
3.2
2.11
0.120
0.091
108
157
0.050
IL
PEORIA CO
182,827
4.7
0.02
0.088
0.073
56
76
0.039
IL
RANDOLPH CO
34,583
0.086
0.072
105
90
0.047
IL
ROCK ISLAND CO
148,723
0.02
0.079
0.066
43
47
0.011
IL
ST CLAIR CO
262,852
0.18
0.0191
0.098
0.080
57
58
0.063
IL
SANGAMON CO
178,386
2.1
0.085
0.071
44
44
0.043
IL
TAZEWELL CO
123,692
52
53
0.044
IL
WABASH CO
13,111
0.041
IL
WILL CO
357,313
1.0
0.02
0.0093
0.083
0.074
59
66
0.021
IL
WINNEBAGO CO
252,913
3.7
0.03
0.084
0.073
62
73
IN
ALLEN CO
300,836
6.3
0.03
0.095
0.087
46
50
IN
CLARK CO
87,777
0.125
0.097
56
72
IN
DAVIESS CO
27,533
0.038
IN
DEARBORN CO
38,835
94
111
0.045
IN
DE KALB CO
35,324
0.6
0.01
77
80
0.014
IN
DELAWARE CO
119,659
0.90
IN
DUBOIS CO
36,616
49
71
IN
ELKHART CO
156,198
0.108
0.089
IN
FLOYD CO
64,404
0.127
0.084
0.038
IN
FOUNTAIN CO
17,808
0.042
IN
GIBSON CO
31,913
0.075
IN
HAMILTON CO
108,936
0.114
0.095
IN
HANCOCK CO
45,527
0.109
0.088
IN
JASPER CO
24,960
42
50
0.016
IN
JEFFERSON CO
29,797
0.024
IN
JOHNSON CO
88,109
0.102
0.084
IN
LAKE CO
475,594
3.8
0.13
0.116
0.094
138
132
0.032
IN
LA PORTE CO
107,066
0.02
0.120
0.096
46
46
0.028
IN
LAWRENCE CO
42,836
0.100
0.087
IN
MADISON CO
130,669
0.091
0.082
45
49
IN
MARION CO
797,159
3.9
0.08
0.0150
0.106
0.090
54
64
0.030
IN
MORGAN CO
55,920
0.103
0.088
0.023
IN
PERRY CO
19,107
0.032
IN
PIKE CO
12,509
0.037
IN
PORTER CO
128,932
0.122
0.091
76
62
0.027
IN
POSEY CO
25,968
0.099
0.087
126 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
IN
ST JOSEPH CO
247,052
0.0124
0.117
0.091
41
48
IN
SPENCER CO
19,490
0.053
IN
SULLIVAN CO
18,993
0.021
IN
VANDERBURGH CO
165,058
5.0
0.114
0.093
67
70
0.053
IN
VERMILLION CO
16,773
49
50
IN
VIGO CO
106,107
2.5
0.096
0.083
61
63
0.025
IN
WARRICK CO
44,920
0.109
0.095
0.083
IN
WAYNE CO
71,951
0.030
IA
BLACK HAWK CO
123,798
53
65
IA
CERRO GORDO CO
46,733
103
94
0.078
IA
CLINTON CO
51,040
73
71
0.029
IA
DELAWARE CO
18,035
48
53
IA
DUBUQUE CO
86,403
0.017
IA
EMMET CO
11,569
44
44
IA
HARRISON CO
14,730
0.079
0.068
IA
LEE CO
38,687
0.043
IA
LINN CO
168,767
2.4
0.075
0.065
50
50
0.073
IA
MUSCATINE CO
39,907
54
66
0.086
IA
PALO ALTO CO
10,669
0.061
IA
POLK CO
327,140
3.8
0.075
0.063
126
126
IA
POTTAWATTAMIE CO
82,628
0.19
IA
SCOTT CO
150,979
0.089
0.072
150
160
0.020
IA
STORY CO
74,252
0.087
0.074
IA
UNION CO
12,750
56
72
IA
VAN BUREN CO
7,676
0.079
0.065
0.008
IA
WARREN CO
36,033
0.074
0.057
IA
WOODBURY CO
98,276
59
102
KS
CLOUD CO
11,023
0.01
31
36
KS
FORD CO
27,463
0.01
38
96
KS
GREELEY CO
1,774
0.01
KS
JOHNSON CO
355,054
0.01
47
72
KS
KEARNEY CO
4,027
117
125
KS
MIAMI CO
23,466
0.079
KS
MORTON CO
3,480
0.01
KS
NORTON CO
5,947
0.20
KS
PAWNEE CO
7,555
1.4
0.080
0.071
56
67
0.004
KS
SEDGWICK CO
403,662
5.3
0.01
0.093
0.079
57
71
0.007
KS
SHAWNEE CO
160,976
0.01
53
60
KS
SHERMAN CO
6,926
0.01
52
57
KS
WYANDOTTE CO
161,993
2.5
0.45
0.0198
0.106
0.081
75
75
0.014
KY
BELL CO
31,506
4.1
0.085
0.073
64
68
KY
BOONE CO
57,589
0.100
0.081
KY
BOYD CO
51,150
3.8
0.0145
0.110
0.086
94
105
0.034
KY
BULLITT CO
47,567
0.0125
0.112
0.086
KY
CAMPBELL CO
83,866
0.0197
0.111
0.089
61
69
0.029
KY
CHRISTIAN CO
68,941
0.099
0.082
KY
DAVIESS CO
87,189
1.0
0.0119
0.108
0.087
59
56
0.027
KY
EDMONSON CO
10,357
0.104
KY
FAYETTE CO
225,366
5.2
0.0135
0.096
0.082
62
58
0.016
KY
FLOYD CO
43,586
38
58
KY
GRAVES CO
33,550
0.101
0.077
KY
GREENUP CO
36,742
0.02
0.114
0.078
0.022
KY
HANCOCK CO
7,864
0.104
0.085
0.023
KY
HARDIN CO
89,240
0.083
0.071
38
44
APPENDIX A: DATA TABLES 127
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
KY
HARLAN CO
36,574
50
58
KY
HENDERSON CO
43,044
2.3
0.0161
0.100
0.082
59
58
0.036
KY
JEFFERSON CO
664,937
6.3
0.02
0.0199
0.122
0.091
98
133
0.037
KY
JESSAMINE CO
30,508
0.099
0.079
KY
KENTON CO
142,031
2.7
0.0182
0.110
0.084
55
52
KY
LAWRENCE CO
13,998
0.082
0.065
50
50
KY
LIVINGSTON CO
9,062
0.112
0.093
37
49
0.019
KY
MC CRACKEN CO
62,879
2.3
0.0120
0.109
0.085
57
64
0.017
KY
MC LEAN CO
9,628
0.103
0.083
KY
MADISON CO
57,508
47
54
KY
MARSHALL CO
27,205
71
83
KY
OLDHAM CO
33,263
0.126
0.085
KY
PERRY CO
30,283
0.073
0.062
43
62
KY
PIKE CO
72,583
0.076
0.064
42
47
KY
PULASKI CO
49,489
0.090
0.073
43
47
KY
SCOTT CO
23,867
0.084
0.072
KY
SIMPSON CO
15,145
0.0110
0.115
0.087
KY
TRIGG CO
10,361
0.106
KY
WARREN CO
76,673
44
52
KY
WHITLEY CO
33,326
52
57
KY
WOODFORD CO
19,955
0.02
LA
ASCENSION PAR
58,214
0.127
0.087
LA
BEAUREGARD PAR
30,083
0.0054
0.117
0.079
LA
BOSSIER PAR
86,088
0.103
0.083
70
99
0.007
LA
CADDO PAR
248,253
0.099
0.084
67
93
LA
CALCASIEU PAR
168,134
0.0055
0.128
0.090
79
89
0.012
LA
EAST BATON ROUGE PAR
380,105
5.4
0.06
0.0202
0.126
0.099
87
93
0.019
LA
GRANT PAR
17,526
0.091
0.075
LA
IBERVILLE PAR
31,049
0.0126
0.126
0.097
50
57
LA
JEFFERSON PAR
448,306
0.0105
0.099
0.080
LA
LAFAYETTE PAR
164,762
0.105
0.078
70
87
LA
LAFOURCHE PAR
85,860
0.103
0.079
LA
LIVINGSTON PAR
70,526
0.0057
0.127
0.089
LA
ORLEANS PAR
496,938
3.3
0.01
0.0181
0.088
0.066
94
100
LA
OUACHITA PAR
142,191
0.086
0.073
78
102
0.009
LA
POINTE COUPEE PAR
22,540
0.0063
0.120
0.089
LA
RAPIDES PAR
131,556
76
92
LA
ST BERNARD PAR
66,631
0.092
0.076
0.017
LA
ST CHARLES PAR
42,437
0.108
0.084
78
82
LA
ST JAMES PAR
20,879
0.0113
0.103
0.078
LA
ST JOHN THE BAPTIST PAR
39,996
0.05
0.108
0.083
LA
ST MARY PAR
58,086
0.101
0.081
LA
WEST BATON ROUGE PAR
19,419
0.04
0.0134
0.113
0.084
70
70
0.027
ME
ANDROSCOGGIN CO
105,259
48
54
0.017
ME
AROOSTOOK CO
86,936
57
56
0.021
ME
CUMBERLAND CO
243,135
0.130
0.103
81
87
0.023
ME
FRANKLIN CO
29,008
33
33
ME
HANCOCK CO
46,948
0.114
0.085
74
78
ME
KENNEBEC CO
115,904
0.102
0.076
81
88
ME
KNOX CO
36,310
0.119
0.090
53
53
ME
OXFORD CO
52,602
0.067
0.057
42
42
0.012
ME
PENOBSCOT CO
146,601
0.094
0.070
52
52
ME
SAGADAHOC CO
33,535
0.125
0.098
ME
YORK CO
164,587
0.0109
0.125
0.101
33
59
128 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
MD
ALLEGANY CO
74,946
56
60
0.020
MD
ANNE ARUNDEL CO
427,239
0.144
0.119
58
76
0.023
MD
BALTIMORE CO
692,134
0.131
0.102
53
71
MD
CALVERT CO
51,372
0.116
0.087
MD
CARROLL CO
123,372
0.115
0.093
MD
CECIL CO
71,347
0.153
0.122
50
51
MD
CHARLES CO
101,154
0.125
0.102
MD
GARRETT CO
28,138
51
53
MD
HARFORD CO
182,132
0.158
0.116
MD
KENT CO
17,842
0.139
0.105
MD
MONTGOMERY CO
757,027
0.117
0.096
MD
PRINCE GEORGES CO
729,268
6.8
0.139
0.110
52
72
MD
WICOMICO CO
74,339
42
49
MD
BALTIMORE
736,014
4.9
0.01
0.0256
0.129
0.107
63
94
0.026
MA
BARNSTABLE CO
186,605
0.116
0.100
MA
BERKSHIRE CO
139,352
0.087
MA
BRISTOL CO
506,325
0.0087
0.123
0.093
43
58
0.024
MA
ESSEX CO
670,080
0.0147
0.118
0.091
36
42
0.029
MA
HAMPDEN CO
456,310
5.3
0.0218
0.126
0.092
58
69
0.021
MA
HAMPSHIRE CO
146,568
0.0088
0.142
0.110
40
40
0.023
MA
MIDDLESEX CO
1,398,468
3.6
0.114
0.092
41
43
0.035
MA
NORFOLK CO
616,087
39
62
MA
PLYMOUTH CO
435,276
0.095
0.071
MA
SUFFOLK CO
663,906
4.7
0.0304
0.092
0.075
59
86
0.049
MA
WORCESTER CO
709,705
3.4
0.0192
0.106
0.092
44
53
0.021
Ml
ALLEGAN CO
90,509
0.117
0.096
Ml
BENZIE CO
12,200
0.105
0.081
Ml
BERRIEN CO
161,378
0.119
0.099
Ml
CALHOUN CO
135,982
48
49
Ml
CASS CO
49,477
0.102
0.090
Ml
CLINTON CO
57,883
0.089
0.078
Ml
DELTA CO
37,780
0.009
Ml
GENESEE CO
430,459
0.01
0.099
0.084
41
44
0.012
Ml
HURON CO
34,951
0.101
0.079
Ml
INGHAM CO
281,912
0.086
0.077
Ml
KALAMAZOO CO
223,411
0.096
0.085
Ml
KENT CO
500,631
2.4
0.01
0.099
0.082
60
57
0.008
Ml
LENAWEE CO
91,476
0.089
0.076
Ml
MACOMB CO
717,400
3.0
0.0124
0.123
0.091
0.018
Ml
MARQUETTE CO
70,887
47
55
Ml
MASON CO
25,537
0.118
0.091
Ml
MONROE CO
133,600
48
55
Ml
MUSKEGON CO
158,983
0.01
0.113
0.086
Ml
OAKLAND CO
1,083,592
2.6
0.088
0.076
Ml
OTTAWA CO
187,768
0.103
0.086
Ml
ST CLAIR CO
145,607
0.118
0.088
0.043
Ml
WASHTENAW CO
282,937
0.088
0.075
Ml
WAYNE CO
2,111,687
4.9
0.09
0.0260
0.114
0.088
106
131
0.044
MN
ANOKA CO
243,641
2.4
0.091
0.078
MN
CARLTON CO
29,259
44
44
MN
DAKOTA CO
275,227
1.1
0.43
0.0135
0.081
0.070
0.020
MN
HENNEPIN CO
1,032,431
3.2
0.01
0.0230
77
74
0.027
MN
KOOCHICHING CO
16,299
0.012
MN
LAKE CO
10,415
0.069
0.063
25
28
APPENDIX A: DATA TABLES 129
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
MN
OLMSTED CO
106,470
38
39
MN
RAMSEY CO
485,765
5.4
0.02
0.0170
68
72
0.016
MN
ST LOUIS CO
198,213
3.2
0.080
0.071
47
63
MN
SHERBURNE CO
41,945
0.007
MN
STEARNS CO
118,791
4.0
MN
WASHINGTON CO
145,896
0.059
0.026
MN
WRIGHT CO
68,710
0.008
MS
ADAMS CO
35,356
0.101
0.077
MS
CHOCTAW CO
9,071
1.1
0.03
0.0035
0.081
0.071
55
73
0.007
MS
COAHOMA CO
31,665
51
69
MS
DE SOTO CO
67,910
0.122
0.082
MS
HANCOCK CO
31,760
0.092
0.078
MS
HARRISON CO
165,365
0.025
MS
HINDS CO
254,441
3.8
0.097
0.079
111
91
0.007
MS
JACKSON CO
115,243
0.114
0.095
57
59
0.016
MS
JONES CO
62,031
59
73
MS
LAUDERDALE CO
75,555
0.092
0.073
MS
LEE CO
65,581
0.0094
0.096
0.079
42
43
0.006
MS
MADISON CO
53,794
0.093
0.075
MS
SHARKEY CO
7,066
0.092
0.077
MS
WARREN CO
47,880
0.097
0.077
58
75
MS
WASHINGTON CO
67,935
57
78
MO
AUDRAIN CO
23,599
32
35
MO
BUCHANAN CO
83,083
93
88
0.147
MO
CLAY CO
153,411
4.7
0.0120
0.121
0.098
0.010
MO
GREENE CO
207,949
4.6
0.0114
0.084
0.068
95
123
0.054
MO
HOLT CO
6,034
1.11
MO
HOWELL CO
31,447
694
694
MO
IRON CO
10,726
1.28
0.073
MO
JACKSON CO
633,232
6.7
0.01
0.084
0.072
54
78
0.021
MO
JEFFERSON CO
171,380
8.53
0.118
0.083
39
41
0.045
MO
MONROE CO
9,104
0.093
0.080
31
37
0.014
MO
PLATTE CO
57,867
0.0104
0.111
0.090
0.008
MO
ST CHARLES CO
212,907
0.0107
0.123
0.090
0.034
MO
STE GENEVIEVE CO
16,037
0.098
0.080
61
67
MO
ST LOUIS CO
993,529
3.8
0.04
0.0215
0.119
0.087
42
42
0.041
MO
TANEY CO
25,561
3.3
MO
ST LOUIS
396,685
5.0
0.0248
0.105
0.084
75
68
0.032
MT
BIG HORN CO
11,337
77
96
MT
BROADWATER CO
3,318
63
63
MT
CASCADE CO
77,691
6.4
0.012
MT
FERGUS CO
12,083
24
24
MT
FLATHEAD CO
59,218
4.9
0.045
136
115
MT
GALLATIN CO
50,463
69
69
MT
JEFFERSON CO
7,939
56
67
MT
LAKE CO
21,041
71
58
MT
LEWIS AND CLARK CO
47,495
1.22
71
66
MT
LINCOLN CO
17,481
84
82
MT
MADISON CO
5,989
24
27
MT
MISSOULA CO
78,687
4.9
91
117
MT
PARK CO
14,562
16
17
MT
PHILLIPS CO
5,163
31
34
MT
RAVALLI CO
25,010
56
61
MT
ROSEBUD CO
10,505
106
106
0.004
130 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
MT
SANDERS CO
8,669
76
76
MT
SILVER BOW CO
33,941
56
57
MT
STILLWATER CO
6,536
19
27
MT
YELLOWSTONE CO
113,419
6.1
95
95
0.043
NE
BUFFALO CO
37,447
55
107
NE
CASS CO
21,318
98
102
NE
DAWSON CO
19,940
57
68
NE
DOUGLAS CO
416,444
5.4
1.95
0.080
0.071
98
102
0.050
NE
LANCASTER CO
213,641
6.9
0.063
0.054
44
57
NV
CHURCHILL CO
17,938
53
53
NV
CLARK CO
741,459
8.1
0.091
0.079
186
138
NV
DOUGLAS CO
27,637
1.7
0.0091
0.083
0.068
49
59
NV
ELKO CO
33,530
48
49
NV
LANDER CO
6,266
64
83
NV
PERSHING CO
4,336
69
99
NV
WASHOE CO
254,667
7.7
0.084
0.069
115
134
NV
WHITE PINE CO
9,264
0.081
0.074
25
25
NV
CARSON CITY
40,443
4.4
0.077
0.073
53
80
NH
BELKNAP CO
49,216
0.089
0.067
NH
CARROLL CO
35,410
0.075
0.065
NH
CHESHIRE CO
70,121
0.092
0.075
47
53
0.022
NH
COOS CO
34,828
0.094
81
108
0.029
NH
GRAFTON CO
74,929
0.073
0.064
NH
HILLSBOROUGH CO
336,073
5.3
0.0155
0.115
0.094
42
61
0.036
NH
MERRIMACK CO
120,005
0.102
0.075
45
52
0.053
NH
ROCKINGHAM CO
245,845
0.0133
0.137
0.102
37
48
0.018
NH
STRAFFORD CO
104,233
0.101
0.080
33
48
NH
SULLIVAN CO
38,592
0.094
0.075
32
56
0.019
NJ
ATLANTIC CO
224,327
3.5
0.131
0.106
0.011
NJ
BERGEN CO
825,380
6.1
0.0277
0.120
0.096
53
78
0.024
NJ
BURLINGTON CO
395,066
4.3
0.023
NJ
CAMDEN CO
502,824
3.3
0.06
0.0217
0.137
0.117
58
89
0.030
NJ
CUMBERLAND CO
138,053
0.115
0.104
0.018
NJ
ESSEX CO
778,206
3.8
0.0306
0.109
0.097
81
90
0.024
NJ
GLOUCESTER CO
230,082
0.128
0.105
45
69
0.019
NJ
HUDSON CO
553,099
6.7
0.0257
0.119
0.105
77
103
0.031
NJ
HUNTERDON CO
107,776
0.120
0.103
NJ
MERCER CO
325,824
0.0166
0.126
0.106
59
87
NJ
MIDDLESEX CO
671,780
3.8
0.08
0.0184
0.139
0.106
0.019
NJ
MONMOUTH CO
553,124
3.2
0.132
0.095
NJ
MORRIS CO
421,353
4.9
0.0114
0.111
0.097
0.027
NJ
OCEAN CO
433,203
4.1
0.150
0.113
NJ
PASSAIC CO
453,060
65
76
NJ
SALEM CO
65,294
0.03
NJ
UNION CO
493,819
5.1
0.0411
0.108
0.089
61
91
0.022
NJ
WARREN CO
91,607
54
83
NM
BERNALILLO CO
480,577
5.9
0.0187
0.091
0.071
93
97
NM
CHAVES CO
57,849
30
34
NM
DONA ANA CO
135,510
4.8
0.08
0.0096
0.102
0.077
144
135
0.022
NM
EDDY CO
48,605
0.0061
0.066
0.007
NM
GRANT CO
27,676
49
52
0.017
NM
HIDALGO CO
5,958
28
83
0.051
NM
LEA CO
55,765
38
39
NM
LUNA CO
18,110
35
40
APPENDIX A: DATA TABLES 131
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
NM
OTERO CO
51,928
61
71
NM
SANDOVAL CO
63,319
1.7
0.0083
0.088
0.076
51
53
NM
SAN JUAN CO
91,605
2.7
0.0098
0.073
0.067
34
79
0.061
NM
SANTA FE CO
98,928
2.1
33
33
NM
TAOS CO
23,118
67
68
NM
VALENCIA CO
45,235
0.067
0.060
NY
ALBANY CO
292,594
2.7
0.03
0.0138
0.099
0.076
45
61
0.020
NY
BRONX CO
1,203,789
3.5
0.0352
0.123
0.096
55
75
0.043
NY
BROOME CO
212,160
48
53
NY
CHAUTAUQUA CO
141,895
0.105
0.087
49
56
0.039
NY
CHEMUNG CO
95,195
0.081
0.073
0.015
NY
DUTCHESS CO
259,462
0.111
0.089
NY
ERIE CO
968,532
3.3
0.04
0.0203
0.088
0.073
51
82
0.094
NY
ESSEX CO
37,152
0.097
0.082
33
42
0.007
NY
GREENE CO
44,739
38
51
NY
HAMILTON CO
5,279
0.091
0.078
0.007
NY
HERKIMER CO
65,797
0.084
0.072
33
36
0.006
NY
JEFFERSON CO
110,943
0.105
0.094
NY
KINGS CO
2,300,664
4.3
0.16
52
91
0.034
NY
MADISON CO
69,120
0.089
0.076
0.020
NY
MONROE CO
713,968
1.9
0.097
0.085
47
55
0.050
NY
NASSAU CO
1,287,348
4.7
0.0248
68
73
0.029
NY
NEWYORK CO
1,487,536
6.1
0.06
0.0399
0.121
0.082
101
105
0.042
NY
NIAGARA CO
220,756
1.4
0.03
0.093
0.081
45
50
0.025
NY
ONEIDA CO
250,836
0.085
0.074
44
49
NY
ONONDAGA CO
468,973
4.0
0.102
0.079
55
57
0.014
NY
ORANGE CO
307,647
0.28
0.102
0.088
NY
PUTNAM CO
83,941
0.119
0.095
39
43
0.014
NY
QUEENS CO
1,951,598
0.135
0.095
0.022
NY
RENSSELAER CO
154,429
39
43
0.014
NY
RICHMOND CO
378,977
0.02
0.156
0.122
57
89
0.024
NY
ROCKLAND CO
265,475
50
52
NY
SARATOGA CO
181,276
0.104
0.083
40
48
NY
SCHENECTADY CO
149,285
4.5
0.089
0.077
42
55
0.017
NY
SUFFOLK CO
1,321,864
0.137
0.106
39
43
0.029
NY
ULSTER CO
165,304
0.097
0.086
43
56
0.013
NY
WAYNE CO
89,123
0.101
0.085
NY
WESTCHESTER CO
874,866
0.115
0.096
NC
ALAMANCE CO
108,213
57
60
NC
ALEXANDER CO
27,544
0.099
0.080
60
100
NC
BEAUFORT CO
42,283
32
43
0.015
NC
BUNCOMBE CO
174,821
0.090
0.075
48
48
NC
CABARRUS CO
98,935
52
53
NC
CALDWELL CO
70,709
0.097
0.079
NC
CAMDEN CO
5,904
0.093
0.084
NC
CASWELL CO
20,693
0.117
0.095
NC
CATAWBA CO
118,412
0.04
47
55
NC
CHATHAM CO
38,759
0.106
0.089
NC
CUMBERLAND CO
274,566
6.0
0.05
0.098
0.085
48
59
NC
DAVIDSON CO
126,677
59
67
NC
DAVIE CO
27,859
0.105
0.092
0.018
NC
DUPLIN CO
39,995
0.092
0.078
NC
DURHAM CO
181,835
6.9
0.097
0.080
59
68
NC
EDGECOMBE CO
56,558
0.106
0.089
54
56
132 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
NC
FORSYTH CO
265,878
4.7
0.0173
0.115
0.093
61
73
0.023
NC
FRANKLIN CO
36,414
0.116
0.097
NC
GASTON CO
175,093
3.3
44
55
NC
GRANVILLE CO
38,345
0.116
0.099
42
47
NC
GUILFORD CO
347,420
4.8
0.00
0.104
0.084
60
69
NC
HALIFAX CO
55,516
55
61
NC
HARNETT CO
67,822
49
51
NC
HAYWOOD CO
46,942
0.106
0.087
49
70
NC
HENDERSON CO
69,285
44
53
NC
JOHNSTON CO
81,306
0.110
0.092
NC
LINCOLN CO
50,319
0.102
0.085
0.016
NC
MC DOWELL CO
35,681
49
61
NC
MARTIN CO
25,078
0.092
0.082
NC
MECKLENBURG CO
511,433
6.0
0.0176
0.120
0.105
61
68
0.016
NC
MITCHELL CO
14,433
56
58
NC
NEW HANOVER CO
120,284
0.102
0.083
39
41
0.028
NC
NORTHAMPTON CO
20,798
0.097
0.088
0.014
NC
ONSLOW CO
149,838
46
52
NC
ORANGE CO
93,851
6.1
NC
PASQUOTANK CO
31,298
46
50
NC
PERSON CO
30,180
0.100
0.088
NC
PITT CO
107,924
0.122
0.097
42
51
0.008
NC
ROBESON CO
105,179
54
59
NC
ROCKINGHAM CO
86,064
0.109
0.089
NC
ROWAN CO
110,605
0.126
0.092
54
63
0.052
NC
SWAIN CO
11,268
0.081
0.070
38
47
NC
WAKE CO
423,380
6.6
0.00
0.112
0.097
59
59
NC
WASHINGTON CO
13,997
0.04
NC
WATAUGA CO
36,952
45
50
NC
WAYNE CO
104,666
49
54
NC
WILSON CO
66,061
38
60
NC
YANCEY CO
15,419
0.085
0.076
ND
BILLINGS CO
1,108
0.005
ND
BURLEIGH CO
60,131
26
27
ND
CASS CO
102,874
0.0080
0.074
0.067
63
67
0.008
ND
DUNN CO
4,005
0.005
ND
GRAND FORKS CO
70,683
64
82
ND
MC KENZIE CO
6,383
0.078
0.071
0.023
ND
MC LEAN CO
10,457
0.008
ND
MERCER CO
9,808
0.0042
0.071
0.064
30
32
0.027
ND
MORTON CO
23,700
0.060
ND
OLIVER CO
2,381
0.0029
0.073
0.062
0.010
ND
STARK CO
22,832
24
29
ND
STEELE CO
2,420
0.0026
0.067
0.062
37
48
0.004
ND
WILLIAMS CO
21,129
34
36
0.022
OH
ADAMS CO
25,371
0.029
OH
ALLEN CO
109,755
0.091
0.083
48
50
0.016
OH
ASHTABULA CO
99,821
0.101
0.090
0.029
OH
ATHENS CO
59,549
37
38
OH
BELMONT CO
71,074
46
49
0.033
OH
BUTLER CO
291,479
0.04
0.118
0.092
76
99
0.035
OH
CLARK CO
147,548
0.113
0.091
0.022
OH
CLERMONT CO
150,187
0.116
0.087
0.020
OH
CLINTON CO
35,415
0.114
0.095
APPENDIX A: DATA TABLES 133
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
OH
COLUMBIANA CO
108,276
0.04
0.0155
61
61
0.048
OH
CUYAHOGA CO
1,412,140
6.1
1.47
0.0281
0.104
0.082
133
117
0.034
OH
DELAWARE CO
66,929
0.099
0.087
OH
FRANKLIN CO
961,437
2.9
0.05
0.100
0.086
73
75
0.025
OH
FULTON CO
38,498
0.42
OH
GEAUGA CO
81,129
0.112
0.091
OH
GREENE CO
136,731
0.111
0.091
40
45
OH
HAMILTON CO
866,228
3.1
0.03
0.0279
0.124
0.093
78
81
0.038
OH
HANCOCK CO
65,536
48
48
OH
JEFFERSON CO
80,298
2.2
0.0172
0.088
0.078
70
63
0.051
OH
KNOX CO
47,473
0.099
0.088
OH
LAKE CO
215,499
2.2
0.121
0.094
57
57
0.057
OH
LAWRENCE CO
61,834
0.099
0.082
61
69
0.024
OH
LICKING CO
128,300
0.108
0.092
46
53
OH
LOGAN CO
42,310
0.25
0.099
0.087
OH
LORAIN CO
271,126
0.095
0.086
55
70
0.021
OH
LUCAS CO
462,361
1.9
0.106
0.085
61
60
0.023
OH
MADISON CO
37,068
0.104
0.089
OH
MAHONING CO
264,806
0.098
0.084
55
59
0.029
OH
MEDINA CO
122,354
0.105
0.089
OH
MEIGS CO
22,987
0.034
OH
MIAMI CO
93,182
0.104
0.087
OH
MONROE CO
15,497
55
64
OH
MONTGOMERY CO
573,809
4.0
0.04
0.097
0.088
63
67
0.032
OH
MORGAN CO
14,194
0.049
OH
NOBLE CO
11,336
65
67
OH
OTTAWA CO
40,029
51
51
OH
PORTAGE CO
142,585
0.096
0.084
OH
PREBLE CO
40,113
0.103
0.085
OH
RICHLAND CO
126,137
63
63
OH
SANDUSKY CO
61,963
98
145
OH
SCIOTO CO
80,327
63
70
0.026
OH
SENECA CO
59,733
61
61
OH
STARK CO
367,585
2.5
0.101
0.084
58
58
0.025
OH
SUMMIT CO
514,990
3.2
0.04
0.109
0.090
63
56
0.072
OH
TRUMBULL CO
227,813
0.110
0.091
53
57
OH
TUSCARAWAS CO
84,090
0.037
OH
UNION CO
31,969
0.075
0.061
OH
WARREN CO
113,909
0.124
0.094
OH
WASHINGTON CO
62,254
0.106
0.084
88
88
OH
WOOD CO
113,269
0.094
0.084
OH
WYANDOT CO
22,254
59
80
OK
CLEVELAND CO
174,253
2.6
0.0120
0.095
0.079
52
59
OK
COMANCHE CO
111,486
0.022
63
71
OK
GARFIELD CO
56,735
0.0088
OK
KAY CO
48,056
43
71
0.027
OK
LATIMER CO
10,333
0.096
OK
MC CLAIN CO
22,795
0.092
0.075
OK
MUSKOGEE CO
68,078
0.0082
88
106
0.011
OK
OKLAHOMA CO
599,611
5.4
0.00
0.0154
0.103
0.084
58
59
OK
OKMULGEE CO
36,490
0.094
0.076
OK
TULSA CO
503,341
6.3
0.02
0.0151
0.114
0.083
77
90
0.049
OR
CLACKAMAS CO
278,850
0.097
0.062
33
37
OR
COLUMBIA CO
37,557
0.071
0.053
134 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
itate
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
OR
DESCHUTES CO
74,958
5.6
87
81
OR
JACKSON CO
146,389
5.7
0.02
0.074
0.063
85
85
OR
JOSEPHINE CO
62,649
5.1
88
88
OR
KLAMATH CO
57,702
5.1
82
82
OR
LAKE CO
7,186
87
76
OR
LANE CO
282,912
5.2
0.02
0.073
0.059
91
91
OR
MARION CO
228,483
5.3
0.081
0.061
OR
MULTNOMAH CO
583,887
4.8
0.06
48
55
OR
UMATILLA CO
59,249
65
60
OR
UNION CO
23,598
79
79
OR
YAMHILL CO
65,551
0.08
PA
ADAMS CO
78,274
0.0040
PA
ALLEGHENY CO
1,336,449
3.8
0.06
0.0294
0.129
0.109
133
113
0.062
PA
ARMSTRONG CO
73,478
0.078
PA
BEAVER CO
186,093
1.9
0.08
0.0170
0.101
0.086
87
80
0.078
PA
BERKS CO
336,523
3.0
0.76
0.0205
0.120
0.095
67
81
0.031
PA
BLAIR CO
130,542
1.5
0.0140
0.114
0.096
67
59
0.046
PA
BUCKS CO
541,174
3.8
0.0196
0.119
0.102
61
59
0.029
PA
CAMBRIA CO
163,029
2.7
0.04
0.0159
0.104
0.092
67
66
0.030
PA
CARBON CO
56,846
0.09
PA
CHESTER CO
376,396
79
105
PA
DAUPHIN CO
237,813
3.3
0.04
0.0185
0.116
0.092
67
62
0.022
PA
DELAWARE CO
547,651
0.05
0.0204
0.127
0.101
76
60
0.033
PA
ERIE CO
275,572
4.9
0.0151
0.103
0.087
68
59
0.035
PA
FRANKLIN CO
121,082
0.114
0.091
PA
LACKAWANNA CO
219,039
2.8
0.0176
0.106
0.087
69
77
0.031
PA
LANCASTER CO
422,822
3.3
0.04
0.0159
0.133
0.102
83
89
0.023
PA
LAWRENCE CO
96,246
3.0
0.0197
0.109
0.086
94
90
0.033
PA
LEHIGH CO
291,130
2.7
0.0157
0.116
0.101
59
55
0.030
PA
LUZERNE CO
328,149
3.3
0.0144
0.111
0.096
67
82
0.026
PA
LYCOMING CO
118,710
0.086
0.076
48
57
0.028
PA
MERCER CO
121,003
0.04
0.111
0.092
49
60
0.032
PA
MONTGOMERY CO
678,111
2.2
0.04
0.0193
0.131
0.107
79
66
0.025
PA
NORTHAMPTON CO
247,105
2.8
0.04
0.0177
0.116
0.092
51
59
0.027
PA
PERRY CO
41,172
0.0069
0.103
0.090
56
67
0.021
PA
PHILADELPHIA CO
1,585,577
5.3
7.00
0.0324
0.125
0.101
264
325
0.048
PA
SCHUYLKILL CO
152,585
1.7
0.035
PA
WARREN CO
45,050
0.069
PA
WASHINGTON CO
204,584
1.6
0.0180
0.118
0.099
60
57
0.050
PA
WESTMORELAND CO
370,321
0.05
0.0168
0.123
0.088
62
75
0.029
PA
YORK CO
339,574
3.4
0.04
0.0189
0.109
0.094
75
82
0.026
Rl
KENT CO
161,135
0.115
0.098
45
52
Rl
PROVIDENCE CO
596,270
5.6
0.0247
0.108
0.085
62
64
0.037
Rl
WASHINGTON CO
110,006
0.113
SC
ABBEVILLE CO
23,862
0.090
0.078
SC
AIKEN CO
120,940
0.01
0.104
0.086
45
46
SC
ANDERSON CO
145,196
0.00
0.100
0.087
SC
BARNWELL CO
20,293
0.108
0.084
44
62
SC
BERKELEY CO
128,776
0.090
0.073
SC
CHARLESTON CO
295,039
3.9
0.01
0.0109
0.102
0.082
49
49
0.022
SC
CHEROKEE CO
44,506
0.104
0.091
SC
CHESTER CO
32,170
0.107
0.089
SC
COLLETON CO
34,377
0.087
0.079
SC
DARLINGTON CO
61,851
0.096
0.085
APPENDIX A: DATA TABLES 135
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
sc
DILLON CO
29,114
0.01
sc
EDGEFIELD CO
18,375
0.093
0.078
sc
FAIRFIELD CO
22,295
53
65
sc
GEORGETOWN CO
46,302
0.02
98
78
0.006
sc
GREENVILLE CO
320,167
5.6
0.01
0.0170
53
51
0.014
sc
GREENWOOD CO
59,567
0.02
sc
LEXINGTON CO
167,611
122
117
0.020
sc
OCONEE CO
57,494
0.090
0.080
0.007
sc
PICKENS CO
93,894
0.097
0.081
sc
RICHLAND CO
285,720
2.9
0.01
0.0112
0.110
0.089
130
123
0.009
sc
SPARTANBURG CO
226,800
0.00
0.107
0.088
43
56
sc
UNION CO
30,337
0.098
0.082
sc
WILLIAMSBURG CO
36,815
0.084
0.071
sc
YORK CO
131,497
0.01
0.098
0.081
46
50
SD
BROOKINGS CO
25,207
52
58
SD
MINNEHAHA CO
123,809
46
52
SD
PENNINGTON CO
81,343
141
141
TN
ANDERSON CO
68,250
0.107
0.084
0.025
TN
BLOUNT CO
85,969
0.115
0.098
43
49
0.048
TN
BRADLEY CO
73,712
0.0143
0.106
0.082
45
49
0.038
TN
DAVIDSON CO
510,784
6.3
0.08
0.0124
0.125
0.097
69
76
0.032
TN
DICKSON CO
35,061
42
42
TN
HAMBLEN CO
50,480
0.096
0.086
41
43
0.037
TN
HAMILTON CO
285,536
0.107
0.089
63
66
TN
HAWKINS CO
44,565
0.069
TN
HAYWOOD CO
19,437
0.094
0.082
TN
HENRY CO
27,888
53
59
TN
HUMPHREYS CO
15,795
0.080
0.016
TN
JEFFERSON CO
33,016
0.124
0.094
TN
KNOX CO
335,749
4.8
0.00
0.120
0.096
67
69
TN
LAWRENCE CO
35,303
0.093
0.079
TN
LOUDON CO
31,255
0.016
TN
MC MINN CO
42,383
0.0147
74
75
0.047
TN
MADISON CO
77,982
0.01
44
52
TN
MAURY CO
54,812
54
64
TN
MONTGOMERY CO
100,498
49
50
0.026
TN
POLK CO
13,643
0.067
TN
PUTNAM CO
51,373
0.099
0.085
TN
ROANE CO
47,227
0.17
58
75
0.024
TN
RUTHERFORD CO
118,570
0.101
0.087
TN
SEVIER CO
51,043
0.110
0.095
TN
SHELBY CO
826,330
5.5
1.30
0.0277
0.122
0.089
76
81
0.033
TN
STEWART CO
9,479
0.017
TN
SULLIVAN CO
143,596
3.5
0.20
0.0183
0.111
0.089
56
63
0.042
TN
SUMNER CO
103,281
0.127
0.100
0.086
TN
UNION CO
13,694
141
137
TN
WASHINGTON CO
92,315
41
56
TN
WILLIAMSON CO
81,021
0.98
0.110
0.092
TN
WILSON CO
67,675
0.104
0.084
TX
BEXAR CO
1,185,394
4.4
0.0220
0.103
0.084
41
58
TX
BRAZORIA CO
191,707
0.137
0.085
TX
BREWSTER CO
8,681
0.066
0.063
TX
CAMERON CO
260,120
3.2
0.080
0.065
103
91
0.001
TX
COLLIN CO
264,036
0.45
0.133
0.102
47
67
136 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
TX
DALLAS CO
1,852,810
4.6
0.09
0.0180
0.134
0.097
66
77
0.005
TX
DENTON CO
273,525
0.0090
0.138
0.105
TX
ELLIS CO
85,167
0.26
0.111
104
126
0.022
TX
EL PASO CO
591,610
7.9
0.12
0.0336
0.115
0.075
209
244
0.030
TX
GALVESTON CO
217,399
0.0050
0.175
0.103
82
116
0.053
TX
GREGG CO
104,948
0.124
0.091
TX
HARRIS CO
2,818,199
6.7
0.00
0.0246
0.210
0.134
134
137
0.025
TX
HIDALGO CO
383,545
0.078
0.067
45
58
TX
JEFFERSON CO
239,397
0.0103
0.133
0.093
0.038
TX
LUBBOCK CO
222,636
38
38
TX
NUECES CO
291,145
0.094
0.077
74
78
0.020
TX
ORANGE CO
80,509
0.0093
0.156
0.090
TX
SMITH CO
151,309
0.101
0.087
TX
TARRANT CO
1,170,103
2.8
0.0156
0.133
0.097
47
58
TX
TRAVIS CO
576,407
1.3
0.112
0.087
TX
VICTORIA CO
74,361
0.092
0.078
TX
WEBB CO
133,239
6.2
0.090
0.063
84
84
UT
CACHE CO
70,183
4.4
0.072
0.063
89
92
UT
DAVIS CO
187,941
3.5
0.0207
0.103
0.079
61
94
0.009
UT
GRAND CO
6,620
43
52
UT
IRON CO
20,789
31
32
UT
SALT LAKE CO
725,956
6.5
0.10
0.0265
0.101
0.075
108
101
0.011
UT
SAN JUAN CO
12,621
0.073
0.067
UT
TOOELE CO
26,601
32
45
0.002
UT
UTAH CO
263,590
6.2
0.0233
0.097
0.075
115
101
UT
WASHINGTON CO
48,560
0.081
44
44
UT
WEBER CO
158,330
6.4
0.0239
0.098
0.075
67
67
VT
BENNINGTON CO
35,845
0.105
0.082
40
56
VT
CHITTENDEN CO
131,761
1.9
0.0166
0.081
0.072
42
46
0.012
VT
RUTLAND CO
62,142
2.9
0.0116
43
49
0.037
VT
WASHINGTON CO
54,928
39
39
VT
WINDHAM CO
41,588
38
50
VA
ARLINGTON CO
170,936
2.4
0.0224
0.126
0.094
VA
CAROLINE CO
19,217
0.0068
0.111
0.091
VA
CARROLL CO
26,594
42
54
VA
CHARLES CITY CO
6,282
0.0119
0.123
0.100
0.017
VA
CHESTERFIELD CO
209,274
0.105
0.090
59
70
VA
CULPEPER CO
27,791
43
86
VA
FAIRFAX CO
818,584
4.6
0.02
0.0236
0.119
0.093
51
69
0.023
VA
FAUQUIER CO
48,741
0.099
0.083
VA
FREDERICK CO
45,723
0.102
0.088
VA
HANOVER CO
63,306
0.134
0.099
VA
HENRICO CO
217,881
0.116
0.098
51
66
VA
HENRY CO
56,942
0.092
0.080
VA
KING WILLIAM CO
10,913
51
72
VA
MADISON CO
11,949
0.101
0.089
VA
NORTHUMBERLAND CO
10,524
48
57
VA
PRINCE WILLIAM CO
215,686
0.0097
0.106
0.086
48
81
VA
ROANOKE CO
79,332
0.0126
0.102
0.084
0.013
VA
ROCKINGHAM CO
57,482
0.011
VA
SMYTH CO
32,370
44
65
VA
STAFFORD CO
61,236
0.108
0.091
VA
TAZEWELL CO
45,960
44
48
VA
WARREN CO
26,142
43
78
APPENDIX A: DATA TABLES 137
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
VA
WISE CO
39,573
47
49
VA
WYTHE CO
25,466
0.093
0.080
VA
ALEXANDRIA
111,183
3.3
0.0259
0.124
0.085
0.024
VA
BRISTOL
18,426
43
65
VA
CHARLOTTESVILLE
40,341
42
51
VA
CHESAPEAKE
151,976
0.01
68
68
VA
COVINGTON
6,991
45
59
VA
FREDERICKSBURG
19,027
54
77
VA
HAMPTON
133,793
0.113
0.097
55
64
0.026
VA
LYNCHBURG
66,049
51
55
VA
MARTINSVILLE
16,162
42
77
VA
NEWPORT NEWS
170,045
4.7
VA
NORFOLK
261,229
3.8
0.0187
0.023
VA
RICHMOND
203,056
3.9
0.01
0.0212
50
69
0.024
VA
ROANOKE
96,397
4.3
95
113
VA
SUFFOLK
52,141
0.114
0.091
55
62
VA
WINCHESTER
21,947
52
87
WA
ASOTIN CO
17,605
122
142
WA
BENTON CO
112,560
77
52
WA
CLALLAM CO
56,464
0.057
0.045
43
46
0.020
WA
CLARK CO
238,053
6.0
0.0124
0.077
0.053
41
42
WA
COWLITZ CO
82,119
46
53
WA
KING CO
1,507,319
6.5
0.87
0.0194
0.095
0.072
115
122
0.012
WA
KITSAP CO
189,731
48
49
WA
PIERCE CO
586,203
6.8
0.083
0.066
97
85
0.029
WA
SKAGIT CO
79,555
0.047
0.038
0.059
WA
SNOHOMISH CO
465,642
5.3
0.070
0.054
63
63
0.009
WA
SPOKANE CO
361,364
6.3
0.083
0.068
79
73
WA
THURSTON CO
161,238
7.3
58
58
WA
WALLA WALLA CO
48,439
127
210
WA
WHATCOM CO
127,780
0.070
0.052
48
48
0.012
WA
YAKIMA CO
188,823
95
110
WV
BERKELEY CO
59,253
0.01
WV
BROOKE CO
26,992
63
63
0.059
WV
CABELL CO
96,827
0.02
0.124
0.086
0.028
WV
FAYETTE CO
47,952
45
46
WV
GREENBRIER CO
34,693
0.0058
0.092
0.085
0.018
WV
HANCOCK CO
35,233
00
00
0.0153
0.097
0.083
113
99
0.061
WV
HARRISON CO
69,371
0.01
WV
KANAWHA CO
207,619
1.9
0.01
0.0197
0.103
0.075
43
46
0.032
WV
MARION CO
57,249
0.01
WV
MARSHALL CO
37,356
51
67
0.061
WV
MONONGALIA CO
75,509
0.01
57
57
0.037
WV
OHIO CO
50,871
3.1
0.110
0.082
48
49
0.034
WV
PUTNAM CO
42,835
57
65
WV
WAYNE CO
41,636
49
49
0.046
WV
WOOD CO
86,915
0.01
0.106
0.085
50
55
0.052
Wl
BROWN CO
194,594
0.091
0.073
0.017
Wl
COLUMBIA CO
45,088
0.088
0.073
Wl
DANE CO
367,085
4.0
0.088
0.079
42
54
0.017
Wl
DODGE CO
76,559
0.093
0.078
Wl
DOOR CO
25,690
0.127
0.100
Wl
DOUGLAS CO
41,758
44
71
Wl
FLORENCE CO
4,590
0.075
0.064
138 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-12. Maximum Air Quality Concentrations by County, 1997 (continued)
CO
Pb
no2
°3
°3
PM10
PM10
so2
State
County
1990
8-hr
QMax
AM
2nd Max
4th Max
2nd Max 99 Pctile
24-hr
Population
(ppm)
(Mg/m3)
(ppm)
(ppm)
(ppm)
(Mg/m3)
(Mg/m3)
(ppm)
Wl
FOND DU LAC CO
90,083
0.089
0.077
Wl
JEFFERSON CO
67,783
0.093
0.078
Wl
KENOSHA CO
128,181
0.120
0.092
Wl
KEWAUNEE CO
18,878
0.121
0.099
Wl
MANITOWOC CO
80,421
0.0037
0.132
0.099
Wl
MARATHON CO
115,400
0.080
0.069
44
45
0.013
Wl
MILWAUKEE CO
959,275
2.5
0.03
0.0207
0.127
0.095
58
59
0.028
Wl
ONEIDA CO
31,679
0.075
0.065
0.050
Wl
OUTAGAMIE CO
140,510
0.094
0.079
Wl
OZAUKEE CO
72,831
0.129
0.099
Wl
POLK CO
34,773
0.5
0.077
0.066
Wl
RACINE CO
175,034
3.1
0.117
0.098
Wl
ROCK CO
139,510
0.097
0.085
Wl
ST CROIX CO
50,251
0.085
0.073
Wl
SAU K CO
46,975
0.0043
0.085
0.071
Wl
SHEBOYGAN CO
103,877
0.123
0.092
Wl
VERNON CO
25,617
0.085
0.071
28
29
Wl
VILAS CO
17,707
21
24
Wl
WALWORTH CO
75,000
0.098
0.081
Wl
WASHINGTON CO
95,328
0.106
0.074
Wl
WAUKESHA CO
304,715
2.1
0.111
0.079
61
61
Wl
WINNEBAGO CO
140,320
0.090
0.080
Wl
WOOD CO
73,605
0.021
WY
ALBANY CO
30,797
53
57
WY
CAMPBELL CO
29,370
44
120
WY
FREMONT CO
33,662
73
69
WY
LARAMIE CO
73,142
26
27
WY
NATRONA CO
61,226
33
34
WY
SHERIDAN CO
23,562
100
96
WY
SWEETWATER CO
38,823
52
62
WY
TETON CO
11,172
0.067
0.061
77
77
CO = Highest second maximum non-overlapping 8-hour concentration (Applicable NAAQS is 9 ppm)
Pb = Highest quarterly maximum concentration (Applicable NAAQS is 1.5 ug/m3)
N02 = Highest arithmetic mean concentration (Applicable NAAQS is 0.053ppm)
03 = Highest second daily maximum 1-hour concentration (Applicable NAAQS is 0.12ppm)
= Highest fourth daily maximum 8-hour concentration (Applicable NAAQS is 0.08ppm)
PM = Highest second maximum 24-hour concentration (Applicable NAAQS is 150 ug/m3)
= Highest 99th percentile 24-hour concentration (Applicable NAAQS is 150ug/rrf)
Data from exceptional events not included.
S02 = Highest second maximum 24-hour concentration (Applicable NAAQS is 0.14ppm)
WTD = Weighted
AM = Annual mean
PPM = Units are parts per million
|jg/m3 = Units are micrograms per cubic meter
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 139
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997
CO
Pb
no2
°3
°3
PM«i
PM10
PM10
S02
so2
Metropolitan Statistical Area
1990
8-hr
QMax
AM
1-hr
8-hr
Wtd AM
2nd Max
99 Pctile
AM
24-hr
Population
(ppm)
(jjg/m3)
(PP"i)
(PP"i)
(PP"i)
(jjg/m3)
(jjg/m3)
(jjg/m3)
(ppm)
(ppm)
ABILENE, TX
119
655
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AGUADILLA, PR
128
172
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AKRON, OH
657
575
3
0.04
ND
0.11
0.09
24
63
56
0.012
0.072
ALBANY, GA
112
561
ND
ND
ND
ND
ND
26
57
80
ND
ND
ALBANY-SCHENECTADY-TROY, NY
861
424
5
0.03
0.014
0.10
0.08
23
45
61
0.004
0.020
ALBUQUERQUE, NM
589
131
6
ND
0.019
0.09
0.08
29
93
97
ND
ND
ALEXANDRIA, LA
131
556
ND
ND
ND
ND
ND
23
76
92
ND
ND
ALLENTOWN-BETHLEHEM-EASTON, PA
595
081
3
0.09
0.018
0.12
0.10
19
59
59
0.010
0.030
ALTOONA, PA
130
542
2
ND
0.014
0.11
0.10
22
67
59
0.010
0.046
AMARILLO, TX
187
547
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ANCHORAGE, AK
226
338
7
ND
ND
ND
ND
32
127
113
ND
ND
ANN ARBOR, Ml
490
058
ND
ND
ND
0.09
0.08
ND
ND
ND
ND
ND
ANNISTON, AL
116
034
ND
ND
ND
ND
ND
23
49
51
ND
ND
APPLETON-OSHKOSH-NEENAH, Wl
315
121
ND
ND
ND
0.09
0.08
ND
ND
ND
ND
ND
ARECIBO, PR
155
005
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ASHEVILLE, NC
191
774
ND
ND
ND
0.09
0.08
21
48
48
ND
ND
ATHENS, GA
126
262
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ATLANTA, GA 2
,959
950
4
0.34
0.025
0.14
0.11
32
75
80
0.005
0.027
ATLANTIC-CAPE MAY, NJ
319
416
4
ND
ND
0.13
0.11
IN
IN
IN
0.003
0.011
AUGUSTA-AIKEN, GA-SC
415
184
ND
0.01
ND
0.12
0.09
26
54
64
0.003
0.013
AURORA-ELGIN, IL
356
884
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AUSTIN-SAN MARCOS, TX
846
227
1
ND
IN
0.11
0.09
ND
ND
ND
ND
ND
BAKERSFIELD, CA
543
477
3
0.00
0.024
0.14
0.11
47
96
137
IN
IN
BALTIMORE, MD 2
,382
172
5
0.01
0.026
0.16
0.12
30
63
94
0.008
0.026
BANGOR, ME
91
629
ND
ND
ND
0.09
0.07
21
52
52
ND
ND
BARNSTABLE-YARMOUTH, MA
134
954
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
BATON ROUGE, LA
528
264
5
0.06
0.020
0.13
0.10
28
87
93
0.006
0.027
BEAUMONT-PORT ARTHUR, TX
361
226
ND
ND
0.010
0.16
0.09
ND
ND
ND
0.008
0.038
BELLINGHAM, WA
127
780
ND
ND
ND
0.07
0.05
16
48
48
IN
IN
BENTON HARBOR, Ml
161
378
ND
ND
ND
0.12
0.10
ND
ND
ND
ND
ND
BERGEN-PASSAIC, NJ 1
,278
440
6
ND
0.028
0.12
0.10
IN
65
78
0.004
0.018
BILLINGS, MT
113
419
6
ND
ND
ND
ND
24
95
95
0.007
0.032
BILOXI-GULFPORT-PASCAGOULA, MS
312
368
ND
ND
ND
0.11
0.10
21
57
59
0.003
0.025
BINGHAMTON, NY
264
497
ND
ND
ND
ND
ND
18
48
53
ND
ND
BIRMINGHAM, AL
840
140
6
ND
0.010
0.12
0.09
35
111
111
0.006
0.018
BISMARCK, ND
83
831
ND
ND
ND
ND
ND
13
26
27
0.008
0.060
BLOOMINGTON, IN
108
978
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
BLOOMINGTON-NORMAL, IL
129
180
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
BOISE CITY, ID
295
851
5
ND
0.019
ND
ND
35
91
161
ND
ND
BOSTON, MA-NH 3
,227
707
5
ND
0.030
0.12
0.09
26
59
86
0.009
0.049
BOULDER-LONGMONT, CO
225
339
5
ND
ND
0.09
0.07
21
42
43
ND
ND
BRAZORIA, TX
191
707
ND
ND
ND
0.14
0.09
ND
ND
ND
ND
ND
BREMERTON, WA
189
731
ND
ND
ND
ND
ND
17
48
49
ND
ND
BRIDGEPORT, CT
443
722
4
ND
0.023
0.14
0.11
IN
51
61
0.007
0.031
BROCKTON, MA
236
409
ND
ND
0.009
0.11
0.09
ND
ND
ND
ND
ND
BROWNSVILLE-HARLINGEN-SAN BENITO, TX
260
120
3
ND
ND
0.08
0.07
21
103
91
0.001
0.001
BRYAN-COLLEGE STATION, TX
121
862
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
BUFFALO-NIAGARA FALLS, NY 1
,189
288
3
0.04
0.020
0.09
0.08
21
51
82
0.012
0.094
BURLINGTON, VT
151
506
2
ND
0.017
ND
ND
IN
42
46
0.002
0.012
CAGUAS, PR
279
501
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
CANTON-MASSILLON, OH
394
106
3
ND
ND
0.10
0.08
27
58
58
0.007
0.025
CASPER, WY
61
226
ND
ND
ND
ND
ND
16
33
34
ND
ND
140 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997 (continued)
CO
Pb
no2
°3
°3
PM«i
PM10
PM10
S02
so2
Metropolitan Statistical Area
1990
8-hr
QMax
AM
1-hr
8-hr
Wtd AM
2nd Max
99 Pctile
AM
24-hr
Population
(ppm)
(jjg/m3)
(PP"i)
(PP"i)
(PP"i)
(jjg/m3)
(jjg/m3)
(jjg/m3)
(ppm)
(ppm)
CEDAR RAPIDS, IA
168
767
2
ND
ND
0.08
0.07
26
50
50
0.007
0.073
CHAMPAIGN-URBAN A, IL
173
025
ND
ND
ND
0.09
0.08
23
44
46
0.004
0.018
CHARLESTON-NORTH CHARLESTON, SC
506
875
4
0.01
0.011
0.10
0.08
22
49
49
0.003
0.022
CHARLESTON, WV
250
454
2
0.01
0.020
0.10
0.08
25
57
65
0.010
0.032
CHARLOTTE-GASTONIA-ROCKHILL, NC-SC
1,162
093
6
0.01
0.018
0.13
0.11
31
61
68
0.006
0.016
CHARLOTTESVILLE, VA
131
107
ND
ND
ND
ND
ND
21
42
51
ND
ND
CHATTANOOGA, TN-GA
424
347
ND
ND
ND
0.11
0.09
26
63
66
ND
ND
CHEYENNE, WY
73
142
ND
ND
ND
ND
ND
IN
26
27
ND
ND
CHICAGO, IL
7,410
858
5
0.33a
0.034
0.11
0.09
38
99
114
0.008
0.041
CHICO-PARADISE, CA
182
120
5
0.00
0.013
0.07
0.07
26
84
108
ND
ND
CINCINNATI, OH-KY-IN
1,526
092
3
0.03
0.028
0.12
0.09
34
94
111
0.010
0.045
CLARKSVILLE-HOPKINSVILLE, TN-KY
169
439
ND
ND
ND
0.10
0.08
21
49
50
0.006
0.026
CLEVELAND-LORAIN-ELYRIA, OH
2,202
069
6
1.47"
0.028
0.12
0.09
43
133
117
0.010
0.057
COLORADO SPRINGS, CO
397
014
5
0.01
ND
0.07
0.06
24
79
78
ND
ND
COLUMBIA, MO
112
379
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
COLUMBIA, SC
453
331
3
0.01
0.011
0.11
0.09
43
130
123
0.004
0.020
COLUMBUS, GA-AL
260
860
ND
0.81c
ND
0.10
0.08
26
64
127
ND
ND
COLUMBUS, OH
1,345
450
3
0.05
ND
0.11
0.09
31
73
75
0.005
0.025
CORPUS CHRISTI, TX
349
894
ND
ND
ND
0.09
0.08
31
74
78
0.003
0.020
CUMBERLAND, MD-WV
101
643
ND
ND
ND
ND
ND
26
56
60
0.006
0.020
DALLAS, TX
2,676
248
5
0.45d
0.018
0.14
0.11
48
104
126
0.003
0.022
DAN BURY, CT
193
597
ND
ND
ND
0.14
0.11
21
46
47
0.005
0.024
DANVILLE, VA
108
711
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
DAVENPORT-MOLINE-ROCK ISLAND, IA-IL 350
861
ND
0.02
ND
0.09
0.07
50
150
160
0.005
0.020
DAYTON-SPRINGFIELD, OH
951
270
4
0.04
ND
0.11
0.09
25
63
67
0.006
0.032
DAYTONA BEACH, FL
399
413
ND
ND
ND
0.09
0.07
21
38
40
ND
ND
DECATUR, AL
131
556
ND
ND
ND
0.09
0.08
23
48
55
ND
ND
DECATUR, IL
117
206
ND
0.03
ND
0.09
0.08
27
46
56
0.006
0.021
DENVER, CO
1,622
980
6
0.03
0.034
0.10
0.08
35
98
94
0.006
0.026
DES MOINES, IA
392
928
4
ND
ND
0.08
0.06
IN
126
126
ND
ND
DETROIT, Ml
4,266
654
5
0.09
0.026
0.12
0.09
38
106
131
0.009
0.044
DOTHAN, AL
130
964
ND
ND
ND
ND
ND
25
50
58
ND
ND
DOVER, DE
110
993
ND
ND
ND
0.12
0.10
ND
ND
ND
ND
ND
DUBUQUE, IA
86
403
ND
ND
ND
ND
ND
ND
ND
ND
IN
IN
DULUTH-SUPERIOR, MN-WI
239
971
3
ND
ND
0.08
0.07
19
47
71
ND
ND
DUTCHESS COUNTY, NY
259
462
ND
ND
ND
0.11
0.09
ND
ND
ND
ND
ND
EAU CLAIRE, Wl
137
543
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
EL PASO, TX
591
610
8
0.12
0.034
0.12
0.08
35
209
244
0.006
0.030
ELKHART-GOSHEN, IN
156
198
ND
ND
ND
0.11
0.09
ND
ND
ND
ND
ND
ELMIRA, NY
95
195
ND
ND
ND
0.08
0.07
ND
ND
ND
0.003
0.015
ENID, OK
56
735
ND
ND
0.009
ND
ND
ND
ND
ND
ND
ND
ERIE, PA
275
572
5
ND
0.015
0.10
0.09
20
68
59
0.009
0.035
EUGENE-SPRINGFIELD, OR
282
912
5
0.02
ND
0.07
0.06
22
91
91
ND
ND
EVANSVILLE-HENDERSON, IN-KY
278
990
5
ND
0.016
0.11
0.10
28
67
70
0.017
0.083
FARGO-MOORHEAD, ND-MN
153
296
ND
ND
0.008
0.07
0.07
18
63
67
0.002
0.008
FAYETTEVILLE, NC
274
566
6
0.05
ND
0.10
0.09
25
48
59
ND
ND
FAYETTEVILLE-SPRINGDALE-ROGERS, AR 259
462
ND
ND
ND
ND
ND
IN
36
54
ND
ND
FITCHBURG-LEOMINSTER, MA
138
165
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
FLAGSTAFF, AZ-UT
101
760
ND
ND
ND
0.08
0.07
IN
IN
IN
ND
ND
FLINT, Ml
430
459
ND
0.01
ND
0.10
0.08
20
41
44
0.002
0.012
FLORENCE, AL
131
327
ND
ND
ND
ND
ND
19
41
44
0.003
0.020
FLORENCE, SC
114
344
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
APPENDIX A: DATA TABLES 141
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997 (continued)
CO
Pb
no2
03
03
PM10
PM10
PM10
so2
so2
Metropolitan Statistical Area
1990
8-hr
QMax
AM
1-hr
8-hr
Wtd AM
2nd Max
99 Pctile
AM
24-hr
Population
(pptn)
(Hg/m3)
(pptn)
(pptn)
(pptn)
(Hg/m3)
(Hg/m3)
(Hg/m3)
(PPm)
(ppm)
FORT COLLINS-LOVE LAND, CO
186
136
5
ND
ND
0.09
0.06
16
34
40
ND
ND
FORT LAUDERDALE, FL 1
,255
488
5
0.04
0.010
0.09
0.07
20
39
60
0.002
0.011
FORT MYERS-CAPE CORAL, FL
335
113
ND
ND
ND
0.08
0.07
18
33
38
ND
ND
FORT PIERCE-PORT ST. LUCIE, FL
251
071
ND
ND
ND
0.08
0.07
18
35
40
ND
ND
FORT SMITH, AR-OK
175
911
ND
ND
ND
ND
ND
22
59
68
ND
ND
FORT WALTON BEACH, FL
143
776
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
FORT WAYNE, IN
456
281
6
0.03
IN
0.10
0.09
33
77
80
IN
IN
FORT WORTH-ARLINGTON, TX
,361
034
3
ND
0.016
0.13
0.10
20
47
58
ND
ND
FRESNO, CA
755
580
7
0.00
0.021
0.14
0.12
47
111
125
IN
IN
GADSDEN, AL
99
840
ND
ND
ND
ND
ND
28
58
63
ND
ND
GAINESVILLE, FL
181
596
ND
ND
ND
0.09
0.08
20
41
75
ND
ND
GALVESTON-TEXAS CITY, TX
217
399
ND
ND
0.005
0.18
0.10
23
82
116
0.006
0.053
GARY, IN
604
526
4
0.13e
IN
0.12
0.09
37
138
132
0.008
0.032
GLENS FALLS, NY
118
539
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
GOLDSBORO, NC
104
666
ND
ND
ND
ND
ND
23
49
54
ND
ND
GRAND FORKS, ND-MN
103
181
ND
ND
ND
ND
ND
23
64
82
ND
ND
GRAND JUNCTION, CO
93
145
5
ND
ND
ND
ND
20
49
48
ND
ND
GRAND RAPIDS-MUSKEGON-HOLLAND, Ml
937
891
2
0.01
IN
0.12
0.10
21
60
57
0.002
0.008
GREAT FALLS, MT
77
691
6
ND
ND
ND
ND
IN
IN
IN
IN
IN
GREELEY, CO
131
821
5
ND
ND
0.10
0.07
IN
56
56
ND
ND
GREEN BAY, Wl
194
594
ND
ND
ND
0.09
0.07
ND
ND
ND
0.003
0.017
GREENSBORO-WINSTON-SALEM-HIGH POINT NC 1
,050
304
5
0.00
0.017
0.12
0.09
27
61
73
0.007
0.023
GREENVILLE, NC
107
924
ND
ND
ND
0.12
0.10
20
42
51
0.005
0.008
GREENVILLE-SPARTANBURG-ANDERSON, SC
830
563
6
0.01
0.017
0.11
0.09
IN
53
56
0.003
0.014
HAGERSTOWN, MD
121
393
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
HAMILTON-MIDDLETOWN, OH
291
479
ND
0.04
ND
0.12
0.09
35
76
99
0.007
0.035
HARRIS BURG-LEBANON-CAR LISLE, PA
587
986
3
0.04
0.019
0.12
0.09
22
67
67
0.007
0.022
HARTFORD, CT 1
,157
585
6
ND
0.018
0.15
0.10
22
47
53
0.005
0.025
HATTIESBURG, MS
98
738
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
HICKORY-MORGANTON-LENOIR, NC
292
409
ND
0.04
ND
0.10
0.08
24
60
100
ND
ND
HONOLULU, HI
836
231
3
0.03
0.005
0.05
0.05
17
28
29
0.002
0.007
HOUMA, LA
182
842
ND
ND
ND
0.10
0.08
ND
ND
ND
ND
ND
HOUSTON, TX 3
,322
025
7
0.00
0.025
0.21
0.13
27
134
137
0.004
0.025
HUNTINGTON-ASHLAND, WV-KY-OH
312
529
4
0.02
0.015
0.12
0.09
39
94
105
0.012
0.046
HUNTSVILLE, AL
293
047
3
ND
ND
0.10
0.09
21
48
50
ND
ND
INDIANAPOLIS, IN 1
,380
491
4
0.08
0.015
0.11
0.10
28
54
64
0.006
0.030
IOWA CITY, IA
96
119
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
JACKSON, Ml
149
756
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
JACKSON, MS
395
396
4
ND
ND
0.10
0.08
26
111
91
0.002
0.007
JACKSON, TN
90
801
ND
0.01
ND
ND
ND
23
44
52
ND
ND
JACKSONVILLE, FL
906
727
3
0.02
0.014
0.12
0.09
26
62
64
0.004
0.035
JACKSONVILLE, NC
149
838
ND
ND
ND
ND
ND
20
46
52
ND
ND
JAMESTOWN, NY
141
895
ND
ND
ND
0.11
0.09
15
49
56
0.008
0.039
JANESVILLE-BELOIT, Wl
139
510
ND
ND
ND
0.10
0.09
ND
ND
ND
ND
ND
JERSEY CITY, NJ
553
099
7
ND
0.026
0.12
0.11
44
77
103
0.010
0.031
JOHNSON CITY-KINGS PORT-BRISTOL, TN-VA
436
047
4
0.20
0.018
0.11
0.09
30
56
65
0.011
0.069
JOHNSTOWN, PA
241
247
3
0.04
0.016
0.10
0.09
24
67
66
0.009
0.030
JONESBORO, AR
68
956
ND
ND
ND
ND
ND
24
60
75
ND
ND
JOPLIN, MO
134
910
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
KALAMAZOO-BATTLE CREEK, Ml
429
453
ND
ND
ND
0.10
0.09
23
48
49
ND
ND
KANKAKEE, IL
96
255
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
KANSAS CITY, MO-KS 1
,582
875
7
0.45
0.020
0.12
0.10
33
75
78
0.005
0.021
142 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997 (continued)
CO
Pb
no2
03
o3
PM10
PM10
PM10
so2
so2
Metropolitan Statistical Area
1990
8-hr
QMax
AM
1-hr
8-hr
Wtd AM
2nd Max
99 Pctile
AM
24-hr
Population (ppm)
(Hg/m3)
(ppm)
(ppm)
(ppm)
(Hg/m3)
(Hg/m3)
(Hg/m3)
(PPm)
(ppm)
KENOSHA, Wl
128
181
ND
ND
ND
0.12
0.09
ND
ND
ND
ND
ND
KILLEEN-TEMPLE, TX
255
301
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
KNOXVILLE, TN
585
960
5
0.00
IN
0.12
0.10
22
141
137
0.008
0.048
KOKOMO, IN
96
946
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
LA CROSSE, WI-MN
116
401
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
LAFAYETTE, LA
344
853
ND
ND
ND
0.11
0.08
22
70
87
ND
ND
LAFAYETTE, IN
161
572
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
LAKE CHARLES, LA
168
134
ND
ND
0.006
0.13
0.09
25
79
89
0.003
0.012
LAKELAND-WINTER HAVEN, FL
405
382
ND
ND
ND
0.10
0.08
IN
IN
IN
0.007
0.017
LANCASTER, PA
422
822
3
0.04
0.016
0.13
0.10
34
83
89
0.007
0.023
LANSING-EAST LANSING, Ml
432
674
ND
ND
ND
0.09
0.08
ND
ND
ND
ND
ND
LAREDO, TX
133
239
6
ND
ND
0.09
0.06
IN
84
84
ND
ND
LAS CRUCES, NM
135
510
5
0.08
0.010
0.10
0.08
42
144
135
0.005
0.022
LAS VEGAS, NV-AZ
852
737
8
ND
IN
0.09
0.08
49
186
138
ND
ND
LAWRENCE, KS
81
798
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
LAWRENCE, MA-NH
353
232
ND
ND
ND
0.10
0.08
15
36
42
0.005
0.027
LAWTON, OK
111
486
IN
ND
IN
0.02
ND
26
63
71
ND
ND
LEWISTON-AUBURN, ME
93
679
ND
ND
ND
ND
ND
21
48
54
0.004
0.017
LEXINGTON, KY
405
936
5
0.02
0.014
0.10
0.08
24
62
58
0.006
0.016
LIMA, OH
154
340
ND
ND
ND
0.09
0.08
24
48
50
0.003
0.016
LINCOLN, NE
213
641
7
ND
ND
0.06
0.05
25
44
57
ND
ND
LITTLE ROCK-NORTH LITTLE ROCK, AR 513
117
5
ND
0.010
0.10
0.08
27
61
86
0.002
0.006
LONGVIEW-MARSHALL, TX
193
801
ND
ND
ND
0.12
0.09
ND
ND
ND
ND
ND
LOS ANGELES-LONG BEACH, CA
8,863
164
15
0.07
0.043
0.17
0.12
46
93
116
0.004
0.010
LOUISVILLE, KY-IN
948
829
6
0.02
0.020
0.13
0.10
34
98
133
0.009
0.038
LOWELL, MA-NH
280
578
4
ND
ND
ND
ND
ND
ND
ND
ND
ND
LUBBOCK, TX
222
636
ND
ND
ND
ND
ND
IN
38
38
ND
ND
LYNCHBURG, VA
193
928
ND
ND
ND
ND
ND
23
51
55
ND
ND
MACON, GA
290
909
ND
ND
ND
0.12
0.10
31
77
102
IN
IN
MADISON, Wl
367
085
4
ND
ND
0.09
0.08
20
42
54
0.003
0.017
MANCHESTER, NH
50
000
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
MANSFIELD, OH
174
007
ND
ND
ND
ND
ND
IN
63
63
ND
ND
MAYAGUEZ, PR
237
143
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
MCALLEN-EDIN BURG-MISS ION, TX
383
545
ND
ND
ND
0.08
0.07
IN
45
58
ND
ND
MEDFORD-ASHLAND, OR
146
389
6
0.02
ND
0.07
0.06
IN
85
85
ND
ND
MELBOURNE-TITUSVILLE-PALM BAY, FL 398
978
ND
ND
ND
0.09
0.08
19
38
42
ND
ND
MEMPHIS, TN-AR-MS
1,007
306
6
1.30'
0.028
0.12
0.09
30
76
81
0.005
0.033
MERCED, CA
178
403
ND
ND
0.013
0.09
0.07
ND
ND
ND
ND
ND
MIAMI, FL
1,937
094
4
ND
0.017
0.11
0.08
26
52
71
0.001
0.004
MIDDLESEX-SOMERSET-HUNTERDON, NJ 1,019
835
4
0.08
0.018
0.14
0.11
ND
ND
ND
0.005
0.019
MILWAUKEE-WAUKESHA, Wl
1,432
149
3
0.03
0.021
0.13
0.10
27
61
61
0.004
0.028
MINNEAPOLIS-ST. PAUL, MN-WI
2,538
834
5
0.433
0.023
0.09
0.08
IN
77
74
0.004
0.027
MOBILE, AL
476
923
ND
ND
ND
0.12
0.08
30
142
166
0.008
0.049
MODESTO, CA
370
522
4
0.00
0.021
0.11
0.09
37
115
119
ND
ND
MONMOUTH-OCEAN, NJ
986
327
4
ND
ND
0.15
0.11
ND
ND
ND
ND
ND
MONROE, LA
142
191
ND
ND
ND
0.09
0.07
IN
78
102
0.004
0.009
MONTGOMERY, AL
292
517
1
ND
0.008
0.09
0.07
24
53
57
0.001
0.005
MUNCIE, IN
119
659
ND
0.90"
ND
ND
ND
ND
ND
ND
ND
ND
MYRTLE BEACH, SC
144
053
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
NAPLES, FL
152
099
ND
ND
ND
ND
ND
18
37
46
ND
ND
NASHUA, NH
168
233
5
ND
0.016
0.12
0.09
19
42
61
0.008
0.036
NASHVILLE, TN
985
026
6
o.gs1
0.012
0.13
0.10
34
69
76
0.007
0.086
APPENDIX A: DATA TABLES 143
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997 (continued)
CO
Pb
no2
03
03
PMi„
PMi„
PMi„
so2
so2
Metropolitan Statistical Area
1990
8-hr
QMax
AM
1-hr
8-hr
Wtd AM 2nd Max 99 Pctile
AM
24-hr
Population (ppm) (|jg/m3) (ppm)
(ppm) (ppm)
(Mg/m3)
(Mg/m3)
(Mg'm3) (ppm)
(PPm)
NASSAU-SUFFOLK, NY
2,609,212
5
ND
0.025
0.14
0.11
23
68
73
0.006
0.029
NEW BEDFORD, MA
175,641
ND
ND
ND
0.12
0.09
18
35
51
ND
ND
NEW HAVEN-MERIDEN, CT
530,180
4
ND
0.024
0.15
0.11
24
64
63
0.006
0.032
NEW LONDON-NORWICH, CT-RI
290,734
ND
ND
ND
0.15
0.11
19
41
65
0.004
0.022
NEW ORLEANS, LA
1,285,270
3
0.05
0.018
0.11
0.08
31
94
100
0.005
0.017
NEWYORK, NY
8,546,846
6
0.16
0.040
0.16
0.12
31
101
105
0.013
0.043
NEWARK, NJ
1,915,928
5
ND
0.041
0.11
0.10
35
81
91
0.007
0.027
NEWBURGH, NY-PA
335,613
ND
0.28
ND
0.10
0.09
ND
ND
ND
ND
ND
NORFOLK-VABEACH-NEWPORT NEWS.VA
1,443,244
5
0.01
0.019
0.11
0.10
22
68
68
0.007
0.026
OAKLAND, CA
2,082,914
4
0.01
0.020
0.11
0.07
24
71
77
0.003
0.012
OCALA, FL
194,833
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ODESSA-MIDLAND, TX
255,545
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
OKLAHOMA CITY, OK
958,839
5
0.00
0.015
0.10
0.08
24
58
59
ND
ND
OLYMPIA, WA
161,238
7
ND
ND
ND
ND
IN
58
58
ND
ND
OMAHA, NE-IA
639,580
5
1.95'
ND
0.08
0.07
42
98
102
0.004
0.050
ORANGE COUNTY, CA
2,410,556
6
ND
0.033
0.13
0.08
39
82
91
0.001
0.006
ORLANDO, FL
1,224,852
4
ND
0.013
0.11
0.08
26
52
53
0.002
0.006
OWENSBORO, KY
87,189
1
ND
0.012
0.11
0.09
26
59
56
0.007
0.027
PANAMA CITY, FL
126,994
ND
ND
ND
ND
ND
26
52
62
ND
ND
PARKERS BURG-MAR I ETTA, WV-OH
149,169
ND
0.01
ND
0.11
0.09
28
88
88
0.010
0.052
PENSACOLA, FL
344,406
ND
ND
ND
0.11
0.09
24
56
57
0.005
0.033
PEORIA-PEKIN, IL
339,172
5
0.02
ND
0.09
0.07
27
56
76
0.007
0.044
PHILADELPHIA, PA-NJ
4,922,175
5
7.00k
0.032
0.14
0.12
64
264
325
0.012
0.048
PHOENIX-MESA, AZ
2,238,480
8
0.03
0.032
0.11
0.09
87
308
301
0.005
0.024
PINE BLUFF, AR
85,487
ND
ND
ND
ND
ND
25
61
78
ND
ND
PITTSBURGH, PA
2,384,811
4
0.08
0.029
0.13
0.11
38
133
113
0.017
0.078
PITTSFIELD, MA
88,695
ND
ND
ND
0.09
0.08
ND
ND
ND
ND
ND
POCATELLO, ID
66,026
ND
ND
IN
ND
ND
21
89
71
0.005
0.034
PONCE, PR
3,442,660
ND
ND
ND
ND
ND
IN
87
91
ND
ND
PORTLAND, ME
221,095
ND
ND
ND
0.13
0.10
23
81
87
0.005
0.023
PORTLAND-VANCOUVER, OR-WA
1,515,452
6
0.08
0.012
0.10
0.06
30
48
55
ND
ND
PORTSMOUTH-ROCHESTER, NH-ME
223,271
ND
ND
0.013
0.14
0.10
IN
37
48
0.004
0.018
PROVIDENCE-FALL RIVER-WARWICK, RI-MA
1,134,350
6
ND
0.025
0.12
0.10
25
62
64
0.008
0.037
PROVO-OREM, UT
263,590
6
ND
0.023
0.10
0.08
27
115
101
ND
ND
PUEBLO, CO
123,051
ND
ND
ND
ND
ND
27
56
88
ND
ND
PUNTA GORDA, FL
110,975
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
RACINE, Wl
175,034
3
ND
ND
0.12
0.10
ND
ND
ND
ND
ND
RALEIGH-DURHAM-CHAPEL HILL, NC
855,545
7
0.00
ND
0.12
0.10
24
59
68
ND
ND
RAPID CITY, SD
81,343
ND
ND
ND
ND
ND
40
141
141
ND
ND
READING, PA
336,523
3
0.76'
0.021
0.12
0.10
30
67
81
0.009
0.031
REDDING, CA
147,036
ND
ND
ND
0.11
0.09
22
56
63
ND
ND
RENO,NV
254,667
8
ND
ND
0.08
0.07
47
115
134
ND
ND
RICHLAND-KENNEWICK-PASCO, WA
150,033
ND
ND
ND
ND
ND
IN
77
52
ND
ND
RICHMOND-PETERSBURG, VA
865,640
4
0.01
0.021
0.13
0.10
25
59
70
0.006
0.024
RIVERSIDE-SAN BERNARDINO, CA
2,588,793
5
0.05
0.036
0.18
0.14
66
133
227
0.002
0.005
ROANOKE, VA
224,477
4
ND
0.013
0.10
0.08
35
95
113
0.003
0.013
ROCHESTER, MN
106,470
ND
ND
ND
ND
ND
IN
38
39
ND
ND
ROCHESTER, NY
1,062,470
2
ND
ND
0.10
0.09
21
47
55
0.010
0.050
ROCKFORD, IL
329,676
4
0.03
ND
0.08
0.07
26
62
73
ND
ND
ROCKY MOUNT, NC
133,235
ND
ND
ND
0.11
0.09
22
54
56
ND
ND
SACRAMENTO, CA
1,340,010
7
0.01
0.019
0.14
0.09
25
104
108
0.002
0.006
SAGINAW-BAY CITY-MIDLAND, Ml
399,320
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ST. CLOUD, MN
190,921
4
ND
ND
ND
ND
ND
ND
ND
ND
ND
144 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997 (continued)
CO
Pb
no2
03
o3
PMi„
PMi„
PMi„
so2
so2
Metropolitan Statistical Area
1990
8-hr
QMax
AM
1-hr
8-hr
Wtd AM 2nd Max 99 Pctile
AM
24-hr
Population (ppm) (|jg/m3) (ppm)
(ppm) (ppm)
(Mg/m3)
(Mg/m3)
(Mg'm3) (ppm)
(PPm)
ST. JOSEPH, MO
83,083
ND
ND
ND
ND
ND
31
93
88
0.008
0.147
ST. LOUIS, MO-IL
1,836,302
5
8.53m
0.025
0.12
0.09
47
108
157
0.010
0.063
SALEM, OR
278,024
5
ND
ND
0.08
0.06
ND
ND
ND
ND
ND
SALINAS, CA
355,660
2
ND
0.010
0.08
0.06
21
70
91
ND
ND
SALT LAKE CITY-OGDEN, UT
1,072,227
7
0.10
0.027
0.10
0.08
35
108
101
0.004
0.011
SAN ANGELO, TX
98,458
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
SAN ANTONIO, TX
1,324,749
4
ND
0.022
0.10
0.08
21
41
58
ND
ND
SAN DIEGO, CA
2,498,016
5
0.03
0.024
0.12
0.09
47
93
125
0.004
0.016
SAN FRANCISCO, CA
1,603,678
4
0.01
0.020
0.08
0.05
25
65
81
0.002
0.006
SAN JOSE, CA
1,497,577
6
0.01
0.025
0.09
0.07
26
72
95
ND
ND
SAN JUAN-BAYAMON, PR
1,836,302
6
ND
IN
0.05
0.04
38
110
109
0.005
0.021
SAN LUIS OBISPO-ATASCADERO-PASO ROBLE CA217.162
2
ND
0.013
0.09
0.07
24
68
75
0.005
0.026
SANTA BARBARA-SANTAMARIA-LOMPOC, CA 369,608
4
0.00
0.019
0.11
0.08
30
63
122
0.002
0.005
SANTA CRUZ-WATSONVILLE, CA
229,734
1
ND
0.004
0.08
0.06
37
88
113
0.001
0.002
SANTA FE, NM
117,043
2
ND
ND
ND
ND
IN
33
33
ND
ND
SANTA ROSA, CA
388,222
3
ND
0.013
0.10
0.08
19
55
85
ND
ND
SARASOTA-BRADENTON, FL
489,483
5
ND
ND
0.11
0.08
28
56
54
0.002
0.012
SAVANNAH, GA
258,060
ND
ND
ND
0.08
0.07
26
49
53
0.004
0.024
SCRANTON-WILKES-BARRE-HAZLETON, PA
638,466
3
ND
0.018
0.11
0.10
26
69
82
0.007
0.031
SEATTLE-BELLEVUE-EVERETT, WA
2,033,156
7
0.87"
0.019
0.10
0.07
29
115
122
0.005
0.012
SHARON, PA
121,003
ND
0.04
ND
0.11
0.09
28
49
60
0.007
0.032
SHEBOYGAN, Wl
103,877
ND
ND
ND
0.12
0.09
ND
ND
ND
ND
ND
SHERMAN-DENISON, TX
95,021
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
SHREVEPORT-BOSSIER CITY, LA
376,330
ND
ND
ND
0.10
0.08
23
70
99
0.002
0.007
SIOUX CITY, IA-NE
115,018
ND
ND
ND
ND
ND
28
59
102
ND
ND
SIOUX FALLS, SD
139,236
ND
ND
ND
ND
ND
23
46
52
ND
ND
SOUTH BEND, IN
247,052
ND
ND
0.012
0.12
0.09
17
41
48
ND
ND
SPOKANE, WA
361,364
6
ND
ND
0.08
0.07
26
79
73
ND
ND
SPRINGFIELD, IL
189,550
2
ND
ND
0.09
0.07
23
44
44
0.006
0.043
SPRINGFIELD, MO
264,346
5
ND
0.011
0.08
0.07
16
95
123
0.004
0.054
SPRINGFIELD, MA
587,884
5
ND
0.022
0.14
0.11
29
58
69
0.005
0.021
STAMFORD-NORWALK, CT
329,935
5
ND
ND
0.14
0.10
31
65
90
0.006
0.030
STATE COLLEGE, PA
123,786
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
STEUBENVILLE-WEIRTON, OH-WV
142,523
9
ND
0.017
0.10
0.08
32
113
99
0.017
0.061
STOCKTON-LODI, CA
480,628
4
0.00
0.022
0.11
0.08
30
95
130
ND
ND
SUMTER, SC
102,637
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
SYRACUSE, NY
742,177
4
ND
ND
0.10
0.08
20
55
57
0.003
0.020
TACOMA, WA
586,203
7
ND
ND
0.08
0.07
20
97
85
0.006
0.029
TALLAHASSEE, FL
233,598
ND
ND
ND
0.06
ND
16
43
43
ND
ND
TAMPA-ST. PETERSBURG-CLEARWATER, FL
2,067,959
4
0.64°
0.012
0.11
0.09
36
87
92
0.008
0.038
TERRE HAUTE, IN
147,585
3
ND
ND
0.10
0.08
27
61
63
0.007
0.025
TEXARKANA, TX-TEXARKANA, AR
120,132
ND
ND
ND
ND
ND
22
64
78
ND
ND
TOLEDO, OH
614,128
2
0.42 p
ND
0.11
0.09
23
61
60
0.004
0.023
TOPEKA, KS
160,976
ND
0.01
ND
ND
ND
28
53
60
ND
ND
TRENTON,NJ
325,824
ND
ND
0.017
0.13
0.11
27
59
87
ND
ND
TUSCON, AZ
666,880
4
0.01
0.018
0.10
0.08
42
129
134
0.002
0.004
TULSA, OK
708,954
6
0.02
0.015
0.11
0.08
27
77
90
0.008
0.049
TUSCALOOSA, AL
150,522
ND
ND
ND
ND
ND
25
55
70
ND
ND
TYLER, TX
151,309
ND
ND
ND
0.10
0.09
ND
ND
ND
ND
ND
UTICA-ROME, NY
316,633
ND
ND
ND
0.09
0.07
11
44
49
0.002
0.006
VALLEJO-FAIRFIELD-NAPA, CA
451,186
5
ND
0.013
0.10
0.07
19
71
85
0.002
0.005
VENTURA, CA
669,016
3
0.00
0.020
0.13
0.11
32
136
253
0.003
0.011
VICTORIA, TX
74,361
ND
ND
ND
0.09
0.08
ND
ND
ND
ND
ND
APPENDIX A: DATA TABLES 145
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-13. Maximum Air Quality Concentrations by Metropolitan Statistical Area, 1997 (continued)
Metropolitan Statistical Area
1990
Population
CO
8-hr
(PP"i)
Pb N02
QMax AM
(Jjg/m3) (ppm)
°3
1-hr
(PP"i)
°3
8-hr
(PP"i)
PM«i
Wtd AM
(jjg/m3)
PM,„
2nd Max
(jjg/m3)
PMi0 S02
99 Pctile AM
(jjg/m3) (ppm)
so2
24-hr
(ppm)
VINELAND-MILLVILLE-BRIDGETON, NJ
138,053
ND
ND
ND
0.12
0.10
ND
ND
ND
0.004
0.018
VISALIA-TULARE-PORTERVILLE, CA
311,921
4
ND
0.019
0.12
0.10
42
86
96
ND
ND
WACO, TX
189,123
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
WASHINGTON, DC-MD-VA-WV
4,223,485
7
0.02
0.026
0.14
0.11
22
54
86
0.008
0.024
WATERBURY, CT
221,629
ND
ND
ND
ND
ND
24
63
59
0.005
0.020
WATERLOO-CEDAR FALLS, IA
123,798
ND
ND
ND
ND
ND
31
53
65
ND
ND
WAUSAU, Wl
115,400
ND
ND
ND
0.08
0.07
20
44
45
0.002
0.013
WEST PALM BEACH-BOCA RATON, FL
863,518
4
0.00
0.012
0.09
0.07
21
39
67
0.002
0.013
WHEELING, WV-OH
159,301
3
ND
ND
0.11
0.08
23
51
67
0.015
0.061
WICHITA, KS
485,270
5
0.01
ND
0.09
0.08
23
57
71
0.005
0.007
WICHITA FALLS, TX
130,351
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
WILLIAMS PORT, PA
118,710
ND
ND
ND
0.09
0.08
26
48
57
0.008
0.028
WILMINGTON-NEWARK, DE-MD
513,293
5
ND
0.018
0.15
0.12
32
68
92
0.010
0.057
WILMINGTON, NC
171,269
ND
ND
ND
0.10
0.08
IN
39
41
0.007
0.028
WORCESTER, MA-CT
478,384
3
ND
0.019
0.11
0.09
19
44
53
0.004
0.021
YAKIMA, WA
188,823
IN
ND
ND
ND
ND
IN
95
110
ND
ND
YOLO, CA
141,092
2
ND
0.010
0.10
0.07
28
60
126
ND
ND
YORK, PA
339,574
3
0.04
0.019
0.11
0.09
31
75
82
0.009
0.026
YOUNGSTOWN-WARREN, OH
600,859
ND
0.04
0.016
0.11
0.09
27
61
61
0.010
0.048
YUBA CITY, CA
122,643
4
ND
0.014
0.10
0.07
29
83
98
ND
ND
YUMA, AZ
106,895
ND
ND
ND
0.07
0.06
IN
IN
IN
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 ug/m3)
N02 = Highest arithmetic mean concentration (Applicable NAAQS is 0.053 ppm)
O (ihr) = Highest second daily maximum 1-hour concentration (Applicable NAAQS is 0.12 ppm)
03 (8hr) = Highest fourth daily maximum 8-hour concentration (Applicable NAAQS is 0.08 ppm)
PM10 = Highest weighted annual mean concentration (Applicable NAAQS is 50 ug/m3)
= Highest second maximum 24-hour concentration (Applicable NAAQS is 150 ug/m3)
= Highest 99th percentile concentration (Applicable NAAQS is 150 ug/m3)
Data from exceptional events not included.
S02 = Highest annual mean concentration (Applicable NAAQS is 0.03ppm)
= Highest second maximum 24-hour concentration (Applicable NAAQS is 0.14ppm)
ND = Indicates data not available
IN = Indicates insufficient data to calculate summary statistic
Wtd = Weighted
AM = Annual mean
|jg/m3 = Units are micrograms per cubic meter
PPM = Units are parts per million
(a) - Localized impact from an industrial source in Chicago, IL. Highest population-oriented site in Chicago, IL is 0.08 |jg/m3.
(b) - Localized impact from an industrial source in Cleveland, OH. This facility has been shut down. Highest population-oriented site in
Cleveland, OH is 0.05 |jg/m3.
(c) - Localized impact from an industrial source in Columbus, GA. Highest population-oriented site in Columbus, GA is 0.16 |jg/m3.
(d) - Localized impact from an industrial source in Collin Co., TX. Highest population-oriented site in Dallas, TX is 0.04 |jg/m3.
(e) - Localized impact from an industrial source in Hammond, IN. Highest population-oriented site in Hammond is 0.04 |jg/m3.
(f) - Localized impact from an industrial source in Memphis, TN. Highest population-oriented site in Memphis, TN is 0.03 |jg/m3.
(g) - Localized impact from an industrial source in Eagan, MN. Highest population-oriented site in Minneapolis, MN is 0.01 |jg/m3.
(h) - Localized impact from an industrial source in Muncie, IN.
(i) - Localized impact from an industrial source in Williamston, Co., TN. Highest population-oriented site in Nashville, TN is 0.08 |jg/m3.
(j) - Localized impact from an industrial source in Omaha, NE. Highest population-oriented site in Omaha, NE is 0.12 |jg/m3.
(k) - Localized impact from an industrial source in Philadelphia, PA. Highest population-oriented site in Philadelphia, PA is 0.81 |jg/m3.
(I) - Localized impact from an industrial source in Laureldale, PA.
(m) - Localized impact from an industrial source in Herculaneum, MO. Highest population-oriented site in St. Louis, MO is 0.03 |jg/m3.
(n) - Localized impact from an industrial source in Seattle.
(o) - Localized impact from an industrial source in Tampa, FL.
(p) - Localized impact from an industrial source in Toledo, OH.
Note: The reader is cautioned that this summary is not adequate in itself to numerically rank MSAs according to their air quality. The monitor-
ing data represent the quality of air in the vicinity of the monitoring site but may not necessarily represent urban-wide air quality.
146 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997
Metropolitan Statistical Area
Trend
#Trend
Sites
1988 19891990 1991 19921993 1994 1995 19961997
AKRON, OH
CO
2nd Max. 8-hr
NS
1
4.6
5.2
5.7
3.3
4.1
3.1
5.3
3.3
3.4
3.2
LEAD
Max. Quarterly Mean
DOWN
2
0.07
0.10
0.04
0.06
0.05
0.06
0.06
0.03
0.04
0.04
OZONE
4th Max. 8-hr
DOWN
2
0.13
0.10
0.09
0.10
0.09
0.09
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
DOWN
2
0.16
0.13
0.11
0.12
0.11
0.11
0.10
0.12
0.11
0.10
PM10
Weighted Annual Mean
DOWN
1
34
34
26
28
27
25
28
26
25
24
99th Percentile
NS
1
86
86
72
62
60
63
71
63
72
56
so2
Arithmetic Mean
DOWN
1
0.015
0.015
0.015
0.015
0.013
0.015
0.012
0.009
0.010
0.012
2nd Max. 24-hr
NS
1
0.056
0.053
0.061
0.051
0.064
0.056
0.042
0.046
0.042
0.072
ALBANY-SCHENECTADY-TROY, NY
CO
2nd Max. 8-hr
DOWN
1
6.2
5.7
6.2
5.4
4.7
3.8
5.2
4.3
3.7
4.5
LEAD
Max. Quarterly Mean
DOWN
1
0.05
0.04
0.13
0.04
0.03
0.03
0.04
0.04
0.03
0.03
OZONE
4th Max. 8-hr
DOWN
3
0.11
0.08
0.08
0.08
0.09
0.08
0.08
0.08
0.07
0.08
2nd Daily Max. 1-hr
NS
3
0.12
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.09
0.10
PM10
Weighted Annual Mean
NS
2
22
22
22
22
21
20
22
19
19
21
99th Percentile
NS
2
54
54
54
62
67
56
69
51
56
60
so2
Arithmetic Mean
DOWN
1
0.006
0.005
0.006
0.007
0.006
0.006
0.006
0.005
0.005
0.004
2nd Max. 24-hr
DOWN
1
0.039
0.022
0.028
0.030
0.022
0.026
0.027
0.016
0.021
0.017
ALBUQUERQUE, NM
CO
2nd Max. 8-hr
DOWN
6
6.7
6.4
6.1
5.5
5.0
5.1
4.9
5.0
4.3
3.7
N02
Arithmetic Mean
NS
1
0.018
0.019
0.018
0.004
0.021
0.024
0.023
0.018
0.022
0.019
OZONE
4th Max. 8-hr
NS
7
0.07
0.07
0.07
0.07
0.07
0.06
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
DOWN
7
0.09
0.09
0.09
0.08
0.09
0.08
0.08
0.08
0.08
0.08
PM10
Weighted Annual Mean
DOWN
8
35
33
24
22
23
23
22
24
24
21
99th Percentile
NS
8
83
80
57
56
53
72
62
66
53
55
ALEXANDRIA, LA
PM10
Weighted Annual Mean
NS
1
23
23
23
22
25
21
23
21
19
23
99th Percentile
NS
1
49
49
49
80
106
66
57
51
44
92
ALLENTOWN-BETHLEHEM-EASTON, PA
CO
2nd Max. 8-hr
DOWN
2
6.8
4.8
5.3
5.3
3.8
3.6
6.6
4.7
3.2
2.9
LEAD
Max. Quarterly Mean
DOWN
2
0.84
0.44
0.24
0.27
0.18
0.12
0.11
0.06
0.06
0.07
N02
Arithmetic Mean
NS
1
0.020
0.020
0.017
0.018
0.018
0.020
0.021
0.018
0.018
0.016
OZONE
4th Max. 8-hr
NS
3
0.12
0.09
0.09
0.10
0.08
0.08
0.08
0.10
0.09
0.10
2nd Daily Max. 1-hr
NS
3
0.15
0.10
0.11
0.12
0.10
0.11
0.11
0.11
0.11
0.11
PM10
Weighted Annual Mean
DOWN
1
31
30
30
30
19
23
24
23
23
23
99th Percentile
NS
1
83
89
93
86
38
65
72
74
74
74
so2
Arithmetic Mean
NS
1
0.012
0.010
0.010
0.008
0.008
0.009
0.010
0.010
0.010
0.010
2nd Max. 24-hr
DOWN
1
0.049
0.047
0.044
0.033
0.030
0.027
0.042
0.027
0.033
0.033
ALTOONA, PA
OZONE
4th Max. 8-hr
NS
1
0.11
0.07
0.08
0.09
0.08
0.09
0.09
0.09
0.08
0.10
2nd Daily Max. 1-hr
NS
1
0.14
0.10
0.10
0.11
0.10
0.10
0.11
0.11
0.10
0.11
PM10
Weighted Annual Mean
NS
1
31
25
21
26
21
23
26
25
25
25
99th Percentile
NS
1
96
64
55
71
38
65
76
58
58
58
so2
Arithmetic Mean
DOWN
1
0.011
0.011
0.011
0.011
0.009
0.009
0.010
0.008
0.008
0.010
2nd Max. 24-hr
NS
1
0.051
0.059
0.062
0.044
0.046
0.052
0.058
0.037
0.033
0.046
ANCHORAGE, AK
PM10
Weighted Annual Mean
DOWN
3
28
26
31
30
31
28
27
26
25
25
99th Percentile
NS
3
98
80
107
104
136
100
103
108
100
90
ANN ARBOR, Ml
OZONE
4th Max. 8-hr
NS
1
0.11
0.08
0.08
0.09
0.08
0.08
0.08
0.08
0.09
0.09
2nd Daily Max. 1-hr
NS
1
0.13
0.10
0.09
0.11
0.10
0.10
0.09
0.11
0.10
0.10
ANNISTON, AL
PM10
Weighted Annual Mean
DOWN
1
28
28
28
29
25
25
24
23
19
23
99th Percentile
NS
1
73
73
73
82
46
90
46
68
40
51
ASHEVILLE, NC
OZONE
4th Max. 8-hr
NS
1
0.07
0.07
0.07
0.06
0.06
0.07
0.07
0.08
0.07
0.08
2nd Daily Max. 1-hr
NS
1
0.08
0.08
0.09
0.08
0.08
0.08
0.08
0.09
0.08
0.09
PM10
Weighted Annual Mean
DOWN
1
29
29
25
24
23
22
19
18
19
21
99th Percentile
NS
1
78
55
53
62
41
56
34
41
44
47
ATLANTA, GA
CO
2nd Max. 8-hr
DOWN
1
5.3
6.2
5.4
6.5
5.1
4.9
5.3
4.5
3.7
4.3
LEAD
Max. Quarterly Mean
NS
2
0.05
0.04
0.03
0.04
0.03
0.02
0.03
0.05
0.03
0.18
N02
Arithmetic Mean
DOWN
2
0.024
0.023
0.021
0.020
0.020
0.020
0.018
0.017
0.021
0.020
OZONE
4th Max. 8-hr
NS
4
0.11
0.09
0.11
0.09
0.09
0.10
0.09
0.11
0.10
0.10
2nd Daily Max. 1-hr
NS
4
0.15
0.11
0.14
0.12
0.12
0.14
0.11
0.14
0.12
0.13
PM10
Weighted Annual Mean
DOWN
2
41
37
46
36
31
31
30
31
29
29
99th Percentile
DOWN
2
93
87
119
87
65
76
66
65
64
72
so2
Arithmetic Mean
DOWN
2
0.007
0.007
0.007
0.006
0.006
0.006
0.004
0.004
0.004
0.004
2nd Max. 24-hr
DOWN
2
0.041
0.043
0.026
0.032
0.028
0.036
0.023
0.018
0.018
0.023
ATLANTIC-CAPE MAY, NJ
LEAD
Max. Quarterly Mean
NS
1
0.04
0.07
0.02
0.03
0.02
0.03
0.04
0.03
0.03
0.03
APPENDIX A: DATA TABLES 147
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
1
0.11
0.10
0.11
0.11
0.09
0.09
0.08
0.10
0.10
0.11
2nd Daily Max. 1-hr
DOWN
1
0.15
0.12
0.16
0.14
0.12
0.12
0.10
0.12
0.11
0.13
PM10
Weighted Annual Mean
DOWN
1
41
37
34
34
31
30
33
32
32
32
99th Percentile
NS
1
97
73
59
71
80
64
59
67
67
67
so2
Arithmetic Mean
DOWN
1
0.006
0.005
0.004
0.004
0.003
0.003
0.003
0.003
0.003
0.003
2nd Max. 24-hr
NS
1
0.025
0.029
0.012
0.011
0.016
0.014
0.019
0.011
0.014
0.011
AUGUSTA-AIKEN, GA-SC
LEAD
Max. Quarterly Mean
DOWN
1
0.02
0.03
0.02
0.01
0.01
0.01
0.01
0.01
0.00
0.01
OZONE
4th Max. 8-hr
NS
2
0.09
0.07
0.08
0.07
0.07
0.09
0.08
0.08
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.11
0.09
0.10
0.10
0.09
0.10
0.09
0.11
0.10
0.11
PM10
Weighted Annual Mean
DOWN
1
27
21
22
23
22
22
21
19
19
21
99th Percentile
DOWN
1
86
53
62
55
67
57
52
62
51
46
AUSTIN-SAN
MARCOS, TX
CO
2nd Max. 8-hr
NS
1
4.2
4.2
5.9
3.4
3.7
3.0
5.8
3.5
3.2
3.2
N02
Arithmetic Mean
UP
1
0.017
0.017
0.017
0.016
0.017
0.017
0.018
0.021
0.018
0.018
OZONE
4th Max. 8-hr
NS
2
0.09
0.08
0.08
0.08
0.08
0.08
0.08
0.09
0.08
0.07
2nd Daily Max. 1-hr
DOWN
2
0.11
0.11
0.11
0.10
0.09
0.09
0.10
0.11
0.10
0.09
PM10
Weighted Annual Mean
DOWN
2
26
25
21
24
23
19
20
22
19
19
99th Percentile
DCWN
2
77
82
44
85
78
53
46
58
36
36
BAKERSFIELD, CA
N02
Arithmetic Mean
DOWN
4
0.018
0.017
0.017
0.017
0.016
0.015
0.015
0.013
0.013
0.013
OZONE
4th Max. 8-hr
NS
5
0.11
0.11
0.10
0.11
0.10
0.11
0.10
0.11
0.11
0.10
2nd Daily Max. 1-hr
NS
5
0.14
0.13
0.13
0.13
0.12
0.13
0.13
0.13
0.14
0.12
PM,„
Weighted Annual Mean
DOWN
1
74
65
69
70
55
44
40
46
36
40
99th Percentile
DOWN
1
206
191
251
189
153
96
133
195
138
125
so2
Arithmetic Mean
NS
1
0.006
0.004
0.004
0.002
0.003
0.002
0.003
0.003
0.003
0.003
2nd Max. 24-hr
DOWN
1
0.016
0.014
0.011
0.010
0.010
0.010
0.007
0.008
0.009
0.009
BALTIMORE,
MD
CO
2nd Max. 8-hr
DOWN
4
7.7
6.7
6.9
6.1
5.4
5.2
5.5
4.3
3.5
4.3
LEAD
Max. Quarterly Mean
DOWN
2
0.08
0.07
0.05
0.04
0.04
0.03
0.03
0.03
0.03
0.02
N02
Arithmetic Mean
DOWN
1
0.034
0.035
0.034
0.033
0.031
0.033
0.032
0.026
0.027
0.026
OZONE
4th Max. 8-hr
NS
7
0.13
0.09
0.10
0.11
0.09
0.11
0.10
0.10
0.09
0.11
2nd Daily Max. 1-hr
NS
7
0.17
0.12
0.13
0.14
0.12
0.13
0.13
0.14
0.12
0.14
PM10
Weighted Annual Mean
DOWN
3
36
36
30
35
30
29
30
28
27
28
99th Percentile
DOWN
3
86
82
76
77
61
69
73
69
61
75
so2
Arithmetic Mean
DOWN
2
0.012
0.012
0.008
0.009
0.009
0.008
0.009
0.006
0.007
0.008
2nd Max. 24-hr
DOWN
2
0.041
0.042
0.030
0.030
0.027
0.026
0.030
0.022
0.026
0.027
BANGOR, ME
PM10
Weighted Annual Mean
DOWN
1
31
26
21
25
22
22
22
20
19
21
99th Percentile
NS
1
67
59
38
51
76
67
77
52
41
52
BATON ROUGE, LA
LEAD
Max. Quarterly Mean
DOWN
2
0.10
0.09
0.06
0.03
0.03
0.02
0.02
0.04
0.03
0.03
N02
Arithmetic Mean
NS
1
0.017
0.015
0.014
0.015
0.016
0.012
0.016
0.016
0.015
0.013
OZONE
4th Max. 8-hr
NS
3
0.10
0.09
0.11
0.09
0.08
0.08
0.08
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
3
0.15
0.14
0.15
0.13
0.11
0.11
0.12
0.12
0.11
0.12
PM10
Weighted Annual Mean
DOWN
2
28
28
28
28
27
22
26
24
24
27
99th Percentile
NS
2
57
59
65
76
91
61
55
57
55
82
so2
Arithmetic Mean
NS
1
0.007
0.007
0.005
0.009
0.008
0.006
0.008
0.006
0.006
0.006
2nd Max. 24-hr
NS
1
0.029
0.056
0.022
0.036
0.033
0.021
0.025
0.034
0.024
0.027
BEAUMONT-PORT ARTHUR,TX
CO
2nd Max. 8-hr
NS
1
3.0
2.0
2.3
2.3
2.4
3.3
2.0
1.7
2.1
2.1
LEAD
Max. Quarterly Mean
NS
1
0.03
0.02
0.02
0.03
0.02
0.02
0.02
0.02
0.02
0.02
N02
Arithmetic Mean
NS
2
0.010
0.010
0.009
0.010
0.011
0.009
0.010
0.010
0.010
0.010
OZONE
4th Max. 8-hr
NS
3
0.10
0.09
0.09
0.10
0.09
0.09
0.08
0.10
0.08
0.09
2nd Daily Max. 1-hr
NS
3
0.14
0.13
0.12
0.13
0.13
0.12
0.11
0.13
0.12
0.14
so2
Arithmetic Mean
DOWN
2
0.008
0.008
0.009
0.008
0.006
0.006
0.006
0.005
0.005
0.006
2nd Max. 24-hr
DOWN
2
0.046
0.088
0.042
0.059
0.044
0.047
0.039
0.025
0.041
0.037
BELLINGHAM, WA
OZONE
4th Max. 8-hr
NS
1
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.05
0.06
0.05
2nd Daily Max. 1-hr
NS
1
0.08
0.08
0.08
0.07
0.07
0.08
0.08
0.08
0.08
0.07
so2
Arithmetic Mean
NS
1
0.005
0.006
0.007
0.006
0.007
0.006
0.007
0.006
0.005
0.005
2nd Max. 24-hr
DOWN
1
0.026
0.018
0.028
0.021
0.022
0.017
0.019
0.018
0.013
0.012
BERGEN-PASSAIC, NJ
CO
2nd Max. 8-hr
DOWN
2
6.8
7.5
6.8
6.6
4.5
5.2
6.2
4.9
3.8
4.8
LEAD
Max. Quarterly Mean
NS
1
0.09
0.05
0.04
0.03
0.02
0.03
0.08
0.03
0.03
0.03
N02
Arithmetic Mean
DOWN
1
0.036
0.035
0.031
0.031
0.030
0.029
0.031
0.029
0.028
0.028
OZONE
4th Max. 8-hr
NS
1
0.13
0.10
0.10
0.10
0.08
0.08
0.09
0.10
0.08
0.10
2nd Daily Max. 1-hr
NS
1
0.19
0.12
0.13
0.14
0.10
0.11
0.11
0.12
0.11
0.12
PM10
Weighted Annual Mean
DOWN
3
38
35
37
39
33
31
35
31
31
31
99th Percentile
NS
3
87
76
95
84
63
79
101
76
73
84
148 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan
Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
so2
Arithmetic Mean
DCWN
2
0.012
0.011
0.010
0.010
0.009
0.008
0.007
0.005
0.006
0.005
2nd Max. 24-hr
DCWN
2
0.053
0.045
0.041
0.035
0.040
0.026
0.037
0.027
0.022
0.021
BILLINGS, MT
so2
Arithmetic Mean
DOWN
4
0.020
0.018
0.016
0.016
0.020
0.021
0.015
0.013
0.009
0.006
2nd Max. 24-hr
DOWN
4
0.095
0.078
0.066
0.069
0.081
0.104
0.066
0.059
0.056
0.032
BILOXI-GULFPORT-PASCAGOULA, MS
so2
Arithmetic Mean
DOWN
1
0.006
0.006
0.007
0.006
0.006
0.004
0.003
0.003
0.003
0.002
2nd Max. 24-hr
NS
1
0.022
0.029
0.037
0.034
0.020
0.029
0.022
0.024
0.043
0.025
BIRMINGHAM, AL
CO
2nd Max. 8-hr
DOWN
4
7.4
7.4
6.9
7.0
6.6
6.6
6.6
6.2
5.4
5.8
LEAD
Max. Quarterly Mean
DOWN
2
2.51
1.23
0.91
1.34
0.62
0.19
0.09
0.08
0.10
0.10
OZONE
4th Max. 8-hr
NS
6
0.09
0.08
0.09
0.08
0.08
0.08
0.08
0.10
0.09
0.08
2nd Daily Max. 1-hr
NS
6
0.12
0.10
0.12
0.10
0.11
0.11
0.10
0.12
0.13
0.11
PM10
Weighted Annual Mean
DOWN
6
37
31
35
32
29
27
25
26
25
26
99th Percentile
NS
6
84
71
79
85
57
72
58
58
54
72
so2
Arithmetic Mean
DOWN
1
0.008
0.008
0.008
0.007
0.007
0.009
0.007
0.006
0.004
0.006
2nd Max. 24-hr
NS
1
0.025
0.025
0.025
0.020
0.027
0.050
0.037
0.016
0.015
0.018
BISMARCK, ND
PM10
Weighted Annual Mean
NS
1
19
21
24
21
21
19
18
20
20
20
99th Percentile
DOWN
1
56
65
107
84
86
56
49
37
37
37
BOISE CITY, ID
PM10
Weighted Annual Mean
DOWN
3
40
42
29
35
34
37
35
30
28
29
99th Percentile
NS
3
134
122
73
148
81
82
105
94
76
69
BOSTON, MA-NH
CO
2nd Max. 8-hr
DOWN
4
5.1
5.0
5.6
4.1
4.7
4.0
4.9
3.6
3.6
3.8
N02
Arithmetic Mean
DOWN
6
0.029
0.028
0.027
0.027
0.026
0.027
0.027
0.024
0.025
0.024
OZONE
4th Max. 8-hr
DOWN
4
0.11
0.09
0.08
0.09
0.09
0.09
0.08
0.09
0.07
0.08
2nd Daily Max. 1-hr
DOWN
4
0.15
0.12
0.10
0.13
0.11
0.11
0.11
0.11
0.09
0.10
PM10
Weighted Annual Mean
DOWN
7
27
26
25
24
22
22
23
21
23
21
99th Percentile
NS
7
58
56
69
53
66
60
60
56
72
60
so2
Arithmetic Mean
DOWN
10
0.012
0.011
0.010
0.009
0.009
0.009
0.008
0.006
0.006
0.007
2nd Max. 24-hr
DOWN
10
0.050
0.044
0.039
0.031
0.038
0.033
0.033
0.024
0.026
0.030
BOULDER-LONGMONT, CO
CO
2nd Max. 8-hr
DOWN
2
6.3
6.6
5.7
5.7
5.9
5.3
4.5
4.2
4.0
4.4
OZONE
4th Max. 8-hr
DOWN
1
0.08
0.08
0.07
0.08
0.07
0.07
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
DOWN
1
0.12
0.11
0.10
0.10
0.09
0.10
0.09
0.10
0.09
0.09
PM10
Weighted Annual Mean
DOWN
2
28
29
23
23
23
24
19
16
17
17
99th Percentile
DOWN
2
88
93
77
74
64
71
43
42
44
35
BRAZORIA,TX
OZONE
4th Max. 8-hr
DOWN
1
0.10
0.10
0.10
0.09
0.10
0.09
0.09
0.11
0.08
0.09
2nd Daily Max. 1-hr
NS
1
0.14
0.15
0.15
0.13
0.13
0.13
0.11
0.15
0.11
0.14
BRIDGEPORT, CT
CO
2nd Max. 8-hr
DOWN
1
6.5
5.2
5.0
5.5
4.7
3.7
5.8
4.9
3.0
4.0
N02
Arithmetic Mean
DOWN
1
0.027
0.026
0.026
0.025
0.024
0.024
0.026
0.024
0.024
0.023
OZONE
4th Max. 8-hr
DOWN
2
0.14
0.11
0.10
0.11
0.08
0.10
0.09
0.10
0.09
0.10
2nd Daily Max. 1-hr
DOWN
2
0.22
0.16
0.15
0.15
0.12
0.16
0.15
0.13
0.11
0.13
PM10
Weighted Annual Mean
DOWN
1
29
27
25
28
22
21
26
22
21
21
99th Percentile
NS
1
71
61
85
60
59
53
69
71
61
61
so2
Arithmetic Mean
DOWN
2
0.012
0.012
0.011
0.010
0.010
0.009
0.009
0.006
0.006
0.007
2nd Max. 24-hr
DOWN
2
0.060
0.047
0.048
0.042
0.037
0.033
0.051
0.031
0.029
0.033
BROCKTON, MA
OZONE
4th Max. 8-hr
NS
1
0.09
0.09
0.09
0.10
0.09
0.09
0.10
0.10
0.08
0.08
2nd Daily Max. 1-hr
DOWN
1
0.13
0.13
0.12
0.15
0.11
0.11
0.12
0.13
0.10
0.10
BROWNSVILLE-HARLINGEN-SAN BENITO, TX
PM10
Weighted Annual Mean
NS
1
22
22
22
24
24
22
23
21
19
21
99th Percentile
NS
1
54
54
54
70
73
69
62
49
41
66
BUFFALO-NIAGARA FALLS, NY
CO
2nd Max. 8-hr
DOWN
3
4.1
4.4
3.4
3.1
4.6
3.4
3.2
2.6
2.9
2.2
LEAD
Max. Quarterly Mean
NS
2
0.07
0.04
0.04
0.03
0.03
0.04
0.05
0.04
0.04
0.04
N02
Arithmetic Mean
NS
2
0.021
0.022
0.020
0.018
0.018
0.017
0.019
0.019
0.019
0.018
OZONE
4th Max. 8-hr
DOWN
2
0.12
0.08
0.09
0.09
0.08
0.08
0.08
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.14
0.10
0.11
0.11
0.11
0.09
0.09
0.10
0.10
0.09
PM10
Weighted Annual Mean
DOWN
12
26
25
20
25
22
19
19
19
20
19
99th Percentile
NS
12
71
68
55
69
62
70
43
47
73
49
so2
Arithmetic Mean
DOWN
4
0.013
0.012
0.011
0.012
0.011
0.010
0.010
0.008
0.007
0.007
2nd Max. 24-hr
DOWN
4
0.062
0.051
0.054
0.062
0.058
0.042
0.039
0.040
0.034
0.040
BURLINGTON, VT
CO
2nd Max. 8-hr
NS
1
3.7
3.7
4.6
3.8
3.9
3.9
3.9
2.5
3.3
1.9
N02
Arithmetic Mean
DOWN
1
0.019
0.019
0.018
0.017
0.016
0.017
0.017
0.017
0.017
0.017
PM10
Weighted Annual Mean
DOWN
2
23
25
24
23
23
21
21
20
20
20
99th Percentile
NS
2
76
63
77
67
51
48
53
85
39
46
APPENDIX A: DATA TABLES 149
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
so2
Arithmetic Mean
DCWN
1
0.007
0.007
0.008
0.008
0.003
0.003
0.003
0.002
0.002
0.002
2nd Max. 24-hr
DCWN
1
0.027
0.031
0.021
0.022
0.013
0.011
0.013
0.006
0.014
0.012
CANTON-MASSILLON, OH
OZONE
4th Max. 8-hr
DOWN
2
0.13
0.09
0.09
0.10
0.08
0.09
0.08
0.09
0.09
0.08
2nd Daily Max. 1-hr
DOWN
2
0.14
0.11
0.10
0.11
0.09
0.10
0.10
0.10
0.10
0.10
PM10
Weighted Annual Mean
DOWN
2
34
35
30
31
28
26
28
29
25
26
99th Percentile
NS
2
98
94
72
64
68
66
72
73
77
56
so2
Arithmetic Mean
DOWN
1
0.011
0.012
0.011
0.010
0.010
0.010
0.009
0.006
0.006
0.007
2nd Max. 24-hr
NS
1
0.039
0.041
0.036
0.037
0.040
0.046
0.052
0.033
0.032
0.025
CEDAR RAPIDS, IA
CO
2nd Max. 8-hr
NS
2
3.9
3.2
4.2
4.3
4.6
3.7
3.8
2.6
5.2
2.5
OZONE
4th Max. 8-hr
NS
2
0.07
0.07
0.06
0.06
0.07
0.06
0.06
0.06
0.06
0.06
2nd Daily Max. 1-hr
NS
2
0.08
0.08
0.07
0.08
0.08
0.07
0.07
0.07
0.07
0.07
PM10
Weighted Annual Mean
DOWN
3
35
33
28
29
27
22
23
23
23
23
99th Percentile
NS
3
70
79
104
63
71
64
50
56
71
53
so2
Arithmetic Mean
DOWN
5
0.006
0.007
0.006
0.006
0.005
0.004
0.004
0.004
0.003
0.004
2nd Max. 24-hr
DOWN
5
0.047
0.049
0.048
0.040
0.036
0.037
0.029
0.028
0.023
0.024
CHAMPAIGN-URBANA, IL
OZONE
4th Max. 8-hr
NS
2
0.10
0.08
0.08
0.09
0.08
0.07
0.09
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.11
0.09
0.10
0.10
0.09
0.08
0.10
0.10
0.09
0.09
PM10
Weighted Annual Mean
DOWN
1
32
32
28
30
31
22
25
22
19
23
99th Percentile
DOWN
1
86
86
68
70
75
51
53
53
49
46
so2
Arithmetic Mean
DOWN
1
0.005
0.005
0.004
0.005
0.004
0.004
0.004
0.003
0.003
0.004
2nd Max. 24-hr
DOWN
1
0.025
0.025
0.030
0.038
0.018
0.015
0.024
0.011
0.013
0.018
CHARLESTON-NORTH CHARLESTON, SC
CO
2nd Max. 8-hr
NS
1
7.5
5.9
4.7
4.9
5.2
5.8
4.0
6.4
4.7
3.9
LEAD
Max. Quarterly Mean
NS
1
0.03
0.02
0.03
0.04
0.01
0.01
0.01
0.01
0.01
0.01
OZONE
4th Max. 8-hr
NS
3
0.09
0.08
0.07
0.07
0.07
0.08
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
3
0.11
0.09
0.09
0.09
0.09
0.10
0.09
0.09
0.10
0.09
PM10
Weighted Annual Mean
DOWN
3
28
29
28
25
23
21
20
19
19
19
99th Percentile
DOWN
3
87
74
72
90
73
52
59
63
63
43
so2
Arithmetic Mean
DOWN
1
0.005
0.005
0.003
0.005
0.005
0.004
0.004
0.003
0.003
0.003
2nd Max. 24-hr
DOWN
1
0.063
0.044
0.027
0.030
0.035
0.025
0.038
0.019
0.021
0.022
CHARLESTON, WV
CO
2nd Max. 8-hr
NS
1
2.8
2.9
2.8
3.1
3.3
2.2
3.5
2.4
2.3
1.9
LEAD
Max. Quarterly Mean
DOWN
2
0.02
0.02
0.04
0.02
0.02
0.02
0.02
0.02
0.02
0.02
N02
Arithmetic Mean
NS
1
0.024
0.021
0.020
0.020
0.017
0.018
0.019
0.020
0.020
0.020
OZONE
4th Max. 8-hr
NS
1
0.12
0.07
0.08
0.09
0.06
0.06
0.08
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
1
0.16
0.10
0.12
0.12
0.07
0.08
0.10
0.11
0.10
0.10
PM10
Weighted Annual Mean
DOWN
1
37
35
36
29
28
29
28
26
24
21
99th Percentile
DOWN
1
104
89
115
68
60
70
59
96
68
46
so2
Arithmetic Mean
DOWN
2
0.013
0.014
0.012
0.009
0.009
0.009
0.010
0.007
0.008
0.009
2nd Max. 24-hr
DOWN
2
0.049
0.062
0.056
0.036
0.031
0.034
0.037
0.023
0.031
0.031
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC
CO
2nd Max. 8-hr
DOWN
5
6.7
7.0
7.1
6.3
6.0
5.6
5.8
4.7
4.4
4.8
LEAD
Max. Quarterly Mean
DOWN
1
0.07
0.03
0.04
0.01
0.08
0.02
0.03
0.01
0.01
0.01
N02
Arithmetic Mean
NS
1
0.017
0.017
0.017
0.016
0.016
0.017
0.016
0.016
0.016
0.018
OZONE
4th Max. 8-hr
NS
3
0.12
0.09
0.10
0.09
0.09
0.10
0.09
0.09
0.10
0.10
2nd Daily Max. 1-hr
NS
3
0.16
0.12
0.12
0.12
0.10
0.13
0.11
0.11
0.13
0.12
PM10
Weighted Annual Mean
DOWN
2
35
34
33
30
30
29
29
26
28
27
99th Percentile
DOWN
2
74
68
63
91
60
58
55
50
52
56
CHARLOTTESVILLE, VA
PM10
Weighted Annual Mean
DOWN
1
40
30
27
28
22
24
22
23
21
21
99th Percentile
DOWN
1
106
64
73
58
38
60
40
57
39
51
CHATTANOOGA,TN-GA
OZONE
4th Max. 8-hr
NS
2
0.10
0.08
0.09
0.08
0.08
0.09
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
2
0.12
0.10
0.12
0.10
0.09
0.10
0.11
0.11
0.11
0.11
PM10
Weighted Annual Mean
DOWN
2
39
36
38
38
34
32
33
32
32
27
99th Percentile
DOWN
2
80
69
75
87
79
69
65
60
64
60
CHICAGO, IL
CO
2nd Max. 8-hr
DOWN
6
5.0
4.8
5.3
4.3
4.8
4.7
6.5
3.7
3.2
3.3
LEAD
Max. Quarterly Mean
DOWN
8
0.15
0.10
0.08
0.06
0.07
0.06
0.06
0.05
0.04
0.04
N02
Arithmetic Mean
NS
4
0.030
0.029
0.025
0.023
0.027
0.027
0.030
0.030
0.030
0.030
OZONE
4th Max. 8-hr
NS
16
0.10
0.08
0.07
0.09
0.07
0.07
0.08
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
16
0.14
0.11
0.09
0.11
0.10
0.09
0.10
0.12
0.10
0.10
PM10
Weighted Annual Mean
DOWN
12
39
39
36
34
33
32
36
33
30
30
99th Percentile
DOWN
12
97
94
105
83
84
84
112
80
65
70
so2
Arithmetic Mean
DOWN
8
0.008
0.007
0.006
0.007
0.005
0.006
0.006
0.005
0.005
0.005
2nd Max. 24-hr
NS
8
0.030
0.027
0.024
0.029
0.025
0.028
0.030
0.022
0.021
0.021
CHICO-PARADISE, CA
CO
2nd Max. 8-hr
DOWN
2
7.2
6.4
6.2
7.4
5.9
4.7
4.6
4.1
4.4
4.0
N02
Arithmetic Mean
DOWN
1
0.016
0.016
0.015
0.016
0.016
0.016
0.015
0.014
0.013
0.013
150 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
DCWN
1
0.08
0.08
0.08
0.07
0.08
0.08
0.08
0.08
0.07
0.07
2nd Daily Max. 1-hr
NS
1
0.10
0.10
0.12
0.09
0.09
0.09
0.10
0.09
0.10
0.07
CINCINNATI, OH-KY-IN
CO
2nd Max. 8-hr
NS
3
3.8
4.9
4.2
4.2
4.5
4.7
4.3
3.4
2.9
2.7
LEAD
Max. Quarterly Mean
DOWN
1
0.09
0.07
0.04
0.04
0.04
0.05
0.04
0.06
0.04
0.03
N02
Arithmetic Mean
NS
2
0.023
0.024
0.022
0.022
0.021
0.022
0.022
0.021
0.022
0.023
OZONE
4th Max. 8-hr
NS
7
0.11
0.09
0.09
0.09
0.08
0.08
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
7
0.14
0.11
0.11
0.12
0.09
0.10
0.11
0.12
0.11
0.11
PM10
Weighted Annual Mean
DOWN
7
40
41
36
32
30
31
30
31
28
29
99th Percentile
DOWN
7
107
98
98
71
67
71
80
72
67
68
so2
Arithmetic Mean
DOWN
5
0.011
0.011
0.012
0.011
0.010
0.011
0.008
0.006
0.008
0.008
2nd Max. 24-hr
DOWN
5
0.049
0.046
0.058
0.041
0.041
0.039
0.041
0.025
0.033
0.035
CLARKSVILLE-HOPKINSVILLE,TN-KY
so2
Arithmetic Mean
DOWN
1
0.010
0.007
0.007
0.006
0.009
0.010
0.007
0.006
0.006
0.005
2nd Max. 24-hr
DOWN
1
0.066
0.042
0.038
0.029
0.036
0.058
0.037
0.019
0.023
0.026
CLEVELAND-LORAIN-ELYRIA, OH
CO
2nd Max. 8-hr
NS
2
5.7
5.9
4.7
4.7
5.1
4.3
5.3
5.7
3.7
3.5
LEAD
Max. Quarterly Mean
DOWN
4
0.26
0.19
0.32
0.18
0.21
0.21
0.14
0.11
0.06
0.06
N02
Arithmetic Mean
DOWN
1
0.023
0.025
0.022
0.022
0.021
0.022
0.021
0.021
0.020
0.020
OZONE
4th Max. 8-hr
NS
6
0.11
0.09
0.08
0.09
0.08
0.09
0.08
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
6
0.14
0.10
0.11
0.11
0.10
0.11
0.11
0.11
0.11
0.10
PM10
Weighted Annual Mean
NS
7
42
41
36
38
33
32
39
36
33
34
99th Percentile
DOWN
7
118
119
97
90
94
85
102
114
89
84
so2
Arithmetic Mean
DOWN
9
0.011
0.012
0.010
0.010
0.009
0.008
0.008
0.006
0.006
0.006
2nd Max. 24-hr
DOWN
9
0.044
0.042
0.041
0.039
0.038
0.039
0.040
0.023
0.030
0.029
COLORADO SPRINGS, CO
CO
2nd Max. 8-hr
DOWN
8
6.1
5.0
4.0
4.3
3.5
3.3
3.2
3.3
3.1
3.1
LEAD
Max. Quarterly Mean
DOWN
1
0.03
0.03
0.03
0.03
0.02
0.02
0.02
0.01
0.01
0.01
N02
Arithmetic Mean
NS
6
0.014
0.014
0.013
0.014
0.015
0.014
0.015
0.015
0.014
0.014
OZONE
4th Max. 8-hr
DOWN
1
0.06
0.07
0.06
0.07
0.06
0.06
0.06
0.06
0.06
0.05
2nd Daily Max. 1-hr
DOWN
1
0.08
0.08
0.07
0.08
0.07
0.06
0.07
0.07
0.07
0.06
PM10
Weighted Annual Mean
DOWN
13
28
27
22
25
22
22
21
19
20
20
99th Percentile
DOWN
13
81
77
80
77
59
60
58
49
52
53
so2
Arithmetic Mean
NS
6
0.003
0.003
0.003
0.003
0.004
0.003
0.004
0.004
0.003
0.003
2nd Max. 24-hr
NS
6
0.013
0.012
0.012
0.013
0.012
0.014
0.015
0.013
0.010
0.010
COLUMBIA, SC
CO
2nd Max. 8-hr
DOWN
1
7.4
6.5
5.8
6.0
6.3
5.6
4.7
4.0
3.4
2.9
LEAD
Max. Quarterly Mean
DOWN
2
0.06
0.03
0.03
0.05
0.04
0.02
0.02
0.01
0.01
0.01
OZONE
4th Max. 8-hr
NS
2
0.10
0.09
0.09
0.08
0.08
0.09
0.08
0.08
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.12
0.11
0.11
0.10
0.10
0.12
0.10
0.10
0.09
0.11
PM10
Weighted Annual Mean
DOWN
4
31
30
29
25
26
24
24
20
23
23
99th Percentile
DOWN
4
76
75
60
53
60
50
60
48
54
50
so2
Arithmetic Mean
DOWN
2
0.003
0.003
0.003
0.003
0.003
0.003
0.002
0.002
0.003
0.003
2nd Max. 24-hr
NS
2
0.019
0.016
0.015
0.019
0.018
0.014
0.013
0.010
0.016
0.015
COLUMBUS,
GA-AL
OZONE
4th Max. 8-hr
NS
2
0.08
0.07
0.07
0.07
0.08
0.08
0.08
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.10
0.09
0.10
0.09
0.09
0.10
0.10
0.11
0.09
0.10
PM10
Weighted Annual Mean
NS
1
26
26
29
27
26
25
27
28
22
26
99th Percentile
NS
1
49
49
68
75
56
74
52
62
63
68
COLUMBUS,
OH
CO
2nd Max. 8-hr
DOWN
3
6.0
5.7
4.1
4.8
4.9
3.9
4.5
3.8
2.5
2.4
LEAD
Max. Quarterly Mean
DOWN
2
0.08
0.08
0.06
0.06
0.06
0.04
0.04
0.04
0.03
0.04
OZONE
4th Max. 8-hr
NS
2
0.11
0.09
0.08
0.09
0.07
0.08
0.09
0.09
0.09
0.08
2nd Daily Max. 1-hr
NS
2
0.14
0.11
0.11
0.12
0.09
0.10
0.10
0.11
0.11
0.10
PM10
Weighted Annual Mean
DOWN
3
31
34
32
31
27
27
27
29
26
28
99th Percentile
DOWN
3
81
86
85
71
70
69
69
80
70
69
so2
Arithmetic Mean
DOWN
1
0.008
0.008
0.008
0.007
0.006
0.007
0.007
0.004
0.004
0.004
2nd Max. 24-hr
NS
1
0.035
0.038
0.038
0.033
0.030
0.034
0.041
0.019
0.021
0.025
CORPUS CHRISTLTX
OZONE
4th Max. 8-hr
NS
2
0.08
0.08
0.08
0.07
0.08
0.08
0.08
0.09
0.08
0.07
2nd Daily Max. 1-hr
NS
2
0.10
0.10
0.10
0.11
0.09
0.12
0.11
0.12
0.10
0.09
PM10
Weighted Annual Mean
NS
2
28
30
27
31
29
29
28
28
23
25
99th Percentile
NS
2
77
77
63
86
98
83
67
57
49
61
so2
Arithmetic Mean
NS
2
0.003
0.003
0.002
0.003
0.003
0.003
0.002
0.002
0.002
0.002
2nd Max. 24-hr
DOWN
2
0.025
0.019
0.013
0.027
0.018
0.024
0.012
0.016
0.013
0.012
CUMBERLAND, MD-WV
so2
Arithmetic Mean
DOWN
1
0.013
0.011
0.010
0.009
0.006
0.008
0.010
0.005
0.003
0.006
2nd Max. 24-hr
DOWN
1
0.055
0.049
0.031
0.028
0.024
0.027
0.037
0.015
0.019
0.020
DALLAS, TX
CO
2nd Max. 8-hr
NS
1
8.0
4.5
4.7
3.8
5.6
5.4
5.3
5.9
5.5
3.7
LEAD
Max. Quarterly Mean
DOWN
9
0.23
0.20
0.21
0.16
0.18
0.19
0.11
0.13
0.08
0.07
N02
Arithmetic Mean
UP
1
0.014
0.012
0.012
0.013
0.015
0.014
0.016
0.019
0.019
0.018
APPENDIX A: DATA TABLES 151
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
2
0.10
0.10
0.10
0.06
0.09
0.10
0.09
0.11
0.09
0.09
2nd Daily Max. 1-hr
NS
2
0.13
0.13
0.14
0.10
0.12
0.13
0.12
0.14
0.12
0.12
PM10
Weighted Annual Mean
NS
5
29
29
28
26
26
27
26
30
30
26
99th Percentile
NS
5
60
61
65
63
81
75
54
80
79
68
DANBURY, CT
OZONE
4th Max. 8-hr
NS
1
0.14
0.10
0.11
0.10
0.08
0.10
0.09
0.09
0.08
0.11
2nd Daily Max. 1-hr
NS
1
0.20
0.13
0.15
0.14
0.12
0.14
0.13
0.13
0.11
0.14
PM10
Weighted Annual Mean
DOWN
1
26
25
22
26
22
19
26
22
22
21
99th Percentile
NS
1
65
52
59
59
58
58
56
69
48
47
so2
Arithmetic Mean
DOWN
1
0.009
0.008
0.007
0.008
0.007
0.006
0.006
0.004
0.005
0.005
2nd Max. 24-hr
DOWN
1
0.051
0.036
0.033
0.032
0.027
0.024
0.037
0.020
0.020
0.024
DAVENPORT-MOLINE-ROCK ISLAND, IA-IL
LEAD
Max. Quarterly Mean
NS
1
0.01
0.02
0.03
0.01
0.02
0.02
0.02
0.01
0.02
0.02
OZONE
4th Max. 8-hr
NS
2
0.09
0.08
0.07
0.08
0.08
0.07
0.07
0.08
0.08
0.07
2nd Daily Max. 1-hr
NS
2
0.11
0.10
0.08
0.09
0.10
0.08
0.09
0.09
0.09
0.08
PM10
Weighted Annual Mean
NS
3
33
32
31
30
29
28
32
34
31
32
99th Percentile
NS
3
106
106
115
62
67
73
81
84
101
85
so2
Arithmetic Mean
DOWN
3
0.004
0.005
0.005
0.004
0.004
0.004
0.004
0.004
0.003
0.003
2nd Max. 24-hr
DOWN
3
0.023
0.025
0.022
0.020
0.019
0.018
0.023
0.017
0.016
0.015
DAYTON-SPRINGFIELD, OH
CO
2nd Max. 8-hr
DOWN
2
4.0
4.8
3.2
3.5
3.6
3.6
3.4
3.0
2.4
3.0
LEAD
Max. Quarterly Mean
DOWN
2
0.08
0.06
0.05
0.04
0.04
0.06
0.04
0.05
0.04
0.04
OZONE
4th Max. 8-hr
NS
3
0.11
0.09
0.09
0.09
0.08
0.09
0.09
0.09
0.10
0.09
2nd Daily Max. 1-hr
NS
3
0.13
0.12
0.11
0.11
0.10
0.11
0.11
0.12
0.11
0.11
PM10
Weighted Annual Mean
DOWN
3
32
31
26
28
25
25
24
26
23
24
99th Percentile
NS
3
83
80
86
60
63
60
61
68
65
58
so2
Arithmetic Mean
NS
2
0.006
0.006
0.006
0.005
0.005
0.006
0.006
0.004
0.005
0.005
2nd Max. 24-hr
NS
2
0.026
0.031
0.023
0.022
0.020
0.031
0.032
0.016
0.027
0.027
DECATUR, AL
PM10
Weighted Annual Mean
NS
1
25
25
25
28
25
25
22
25
21
23
99th Percentile
NS
1
62
62
62
68
50
64
66
65
53
55
DECATUR, IL
LEAD
Max. Quarterly Mean
DOWN
1
0.10
0.07
0.03
0.03
0.03
0.03
0.05
0.03
0.02
0.03
OZONE
4th Max. 8-hr
NS
1
0.09
0.08
0.08
0.09
0.08
0.07
0.08
0.08
0.09
0.08
2nd Daily Max. 1-hr
NS
1
0.11
0.09
0.09
0.10
0.09
0.08
0.10
0.10
0.10
0.09
PM10
Weighted Annual Mean
DOWN
1
40
40
34
36
38
28
29
30
28
27
99th Percentile
DOWN
1
99
98
88
85
75
64
66
59
55
56
so2
Arithmetic Mean
DOWN
1
0.015
0.012
0.008
0.007
0.005
0.006
0.007
0.005
0.005
0.006
2nd Max. 24-hr
DOWN
1
0.162
0.108
0.060
0.039
0.023
0.025
0.030
0.024
0.022
0.021
DENVER, CO
CO
2nd Max. 8-hr
DOWN
6
9.9
7.8
7.2
7.0
8.3
6.6
6.1
5.6
4.8
4.7
LEAD
Max. Quarterly Mean
DOWN
3
0.07
0.05
0.06
0.05
0.06
0.06
0.04
0.05
0.03
0.02
N02
Arithmetic Mean
DOWN
2
0.033
0.033
0.032
0.032
0.032
0.027
0.032
0.029
0.027
0.029
OZONE
4th Max. 8-hr
DOWN
5
0.08
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
DOWN
5
0.11
0.10
0.10
0.09
0.09
0.09
0.09
0.09
0.09
0.09
PM10
Weighted Annual Mean
DOWN
10
28
27
26
26
26
29
25
21
22
23
99th Percentile
NS
10
75
96
87
89
115
99
74
55
56
72
so2
Arithmetic Mean
DOWN
2
0.007
0.006
0.006
0.006
0.007
0.006
0.006
0.004
0.005
0.005
2nd Max. 24-hr
NS
2
0.022
0.023
0.020
0.026
0.038
0.025
0.025
0.016
0.020
0.021
DES MOINES,
IA
CO
2nd Max. 8-hr
NS
3
3.9
4.4
4.6
4.6
3.9
4.5
3.9
4.0
3.2
3.0
OZONE
4th Max. 8-hr
UP
2
0.04
0.05
0.04
0.04
0.07
0.05
0.05
0.07
0.06
0.06
2nd Daily Max. 1-hr
UP
2
0.06
0.06
0.07
0.06
0.08
0.08
0.07
0.08
0.08
0.08
PM10
Weighted Annual Mean
NS
3
35
33
32
29
28
29
30
30
31
33
99th Percentile
NS
3
86
89
94
67
84
79
99
80
91
93
DETROIT, Ml
CO
2nd Max. 8-hr
NS
6
5.4
6.0
4.5
5.1
4.2
4.5
6.6
4.5
3.9
3.3
LEAD
Max. Quarterly Mean
DOWN
5
0.05
0.05
0.04
0.04
0.03
0.03
0.03
0.02
0.03
0.04
N02
Arithmetic Mean
NS
1
0.023
0.025
0.024
0.022
0.021
0.022
0.025
0.022
0.020
0.026
OZONE
4th Max. 8-hr
NS
8
0.10
0.09
0.08
0.09
0.08
0.08
0.09
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
8
0.14
0.12
0.10
0.12
0.10
0.10
0.12
0.12
0.10
0.11
PM10
Weighted Annual Mean
DOWN
6
38
39
36
33
28
33
38
35
31
28
99th Percentile
NS
6
100
91
93
83
77
95
102
91
74
81
so2
Arithmetic Mean
DOWN
10
0.010
0.010
0.010
0.008
0.007
0.007
0.007
0.006
0.006
0.005
2nd Max. 24-hr
DOWN
10
0.039
0.037
0.038
0.033
0.030
0.030
0.032
0.030
0.034
0.027
DOTHAN, AL
PM10
Weighted Annual Mean
NS
1
26
26
31
28
25
26
28
28
22
25
99th Percentile
NS
1
54
54
82
68
70
64
97
57
65
58
DUBUQUE, IA
so2
Arithmetic Mean
NS
1
0.005
0.005
0.005
0.004
0.004
0.003
0.005
0.006
0.003
0.003
2nd Max. 24-hr
DOWN
1
0.052
0.030
0.037
0.028
0.029
0.014
0.037
0.027
0.022
0.022
152 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
DULUTH-SUPERIOR, MN-WI
CO
2nd Max. 8-hr
NS
1
5.1
9.9
4.4
5.2
4.0
4.1
4.3
4.5
4.5
3.2
PM10
Weighted Annual Mean
DOWN
6
27
26
22
23
20
19
19
19
19
19
99th Percentile
NS
6
65
58
61
69
64
45
55
59
55
51
EL PASO, TX
CO
2nd Max. 8-hr
DOWN
5
9.1
9.8
10.9
9.1
8.1
8.0
6.6
6.8
8.4
6.9
LEAD
Max. Quarterly Mean
DOWN
4
0.26
0.30
0.27
0.27
0.19
0.18
0.12
0.13
0.20
0.09
N02
Arithmetic Mean
NS
1
0.021
0.022
0.017
0.019
0.021
0.021
0.023
0.023
0.023
0.021
OZONE
4th Max. 8-hr
NS
3
0.08
0.08
0.08
0.07
0.07
0.07
0.08
0.08
0.08
0.07
2nd Daily Max. 1-hr
DOWN
3
0.14
0.13
0.12
0.12
0.12
0.11
0.13
0.11
0.12
0.11
PM10
Weighted Annual Mean
DOWN
6
47
42
36
30
30
27
28
31
29
25
99th Percentile
NS
6
122
116
109
83
89
64
84
100
96
94
so2
Arithmetic Mean
DOWN
3
0.014
0.013
0.010
0.010
0.012
0.009
0.007
0.008
0.008
0.007
2nd Max. 24-hr
DOWN
3
0.059
0.055
0.055
0.047
0.053
0.049
0.029
0.038
0.036
0.031
ELMIRA, NY
OZONE
4th Max. 8-hr
NS
1
0.10
0.07
0.08
0.09
0.07
0.08
0.07
0.08
0.07
0.07
2nd Daily Max. 1-hr
DOWN
1
0.12
0.09
0.10
0.10
0.09
0.09
0.08
0.09
0.09
0.08
so2
Arithmetic Mean
DOWN
1
0.007
0.005
0.005
0.005
0.005
0.005
0.004
0.004
0.004
0.003
2nd Max. 24-hr
DOWN
1
0.027
0.026
0.021
0.022
0.021
0.019
0.023
0.014
0.016
0.015
ERIE, PA
CO
2nd Max. 8-hr
DOWN
1
4.9
4.4
5.1
3.8
3.6
4.4
3.7
3.2
3.2
3.2
N02
Arithmetic Mean
NS
1
0.016
0.015
0.015
0.013
0.014
0.014
0.015
0.015
0.015
0.015
OZONE
4th Max. 8-hr
DOWN
1
0.12
0.09
0.08
0.09
0.08
0.08
0.09
0.09
0.08
0.09
2nd Daily Max. 1-hr
NS
1
0.15
0.12
0.10
0.11
0.10
0.11
0.10
0.11
0.10
0.10
PM10
Weighted Annual Mean
NS
1
35
27
27
29
22
26
29
29
29
29
99th Percentile
NS
1
111
73
75
81
57
72
57
115
115
115
so2
Arithmetic Mean
DOWN
1
0.014
0.014
0.014
0.010
0.011
0.011
0.010
0.009
0.011
0.009
2nd Max. 24-hr
NS
1
0.050
0.074
0.057
0.044
0.056
0.072
0.076
0.050
0.066
0.035
EUGENE-SPRINGFIELD, OR
CO
2nd Max. 8-hr
DOWN
1
7.1
6.0
4.8
5.4
6.0
4.7
5.3
4.7
4.6
4.7
LEAD
Max. Quarterly Mean
NS
1
0.03
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
OZONE
4th Max. 8-hr
NS
2
0.09
0.06
0.07
0.07
0.07
0.05
0.07
0.06
0.09
0.06
2nd Daily Max. 1-hr
NS
2
0.12
0.08
0.09
0.09
0.10
0.08
0.09
0.08
0.11
0.07
PM10
Weighted Annual Mean
DOWN
4
35
31
28
33
29
29
25
23
20
21
99th Percentile
DOWN
4
102
109
88
121
89
89
91
72
64
64
EVANSVILLE-HENDERSON, IN-KY
CO
2nd Max. 8-hr
NS
1
3.1
2.3
2.5
2.0
2.3
2.6
2.7
2.7
2.0
2.3
N02
Arithmetic Mean
DOWN
1
0.022
0.020
0.018
0.021
0.018
0.017
0.018
0.017
0.017
0.016
OZONE
4th Max. 8-hr
NS
4
0.10
0.09
0.09
0.09
0.08
0.08
0.10
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
4
0.12
0.10
0.10
0.10
0.09
0.10
0.11
0.11
0.10
0.11
PM10
Weighted Annual Mean
DOWN
3
38
36
32
34
30
30
33
32
26
27
99th Percentile
NS
3
86
86
85
65
61
70
110
74
53
61
so2
Arithmetic Mean
DOWN
7
0.012
0.013
0.014
0.013
0.012
0.012
0.012
0.010
0.011
0.011
2nd Max. 24-hr
DOWN
7
0.059
0.056
0.062
0.061
0.068
0.051
0.048
0.042
0.048
0.048
FARGO-MOORHEAD, ND-MN
PM10
Weighted Annual Mean
NS
1
21
21
21
19
21
18
18
20
20
20
99th Percentile
NS
1
57
51
76
59
58
46
44
56
56
56
FAYETTEVILLE-SPRINGDALE-ROGERS, AR
PM10
Weighted Annual Mean
NS
1
26
26
23
24
22
24
25
24
23
20
99th Percentile
DOWN
1
66
66
60
47
64
60
53
52
57
54
FAYETTEVILLE, NC
OZONE
4th Max. 8-hr
NS
2
0.08
0.08
0.09
0.08
0.08
0.09
0.08
0.08
0.09
0.09
2nd Daily Max. 1-hr
NS
2
0.10
0.10
0.10
0.10
0.09
0.11
0.10
0.10
0.10
0.10
PM10
Weighted Annual Mean
DOWN
1
33
29
31
27
26
27
25
23
25
25
99th Percentile
NS
1
79
55
59
53
56
59
58
44
53
59
FLINT, Ml
OZONE
4th Max. 8-hr
NS
1
0.11
0.08
0.08
0.09
0.07
0.07
0.07
0.08
0.08
0.08
2nd Daily Max. 1-hr
NS
1
0.13
0.10
0.10
0.10
0.09
0.10
0.09
0.09
0.10
0.10
FLORENCE, AL
PM10
Weighted Annual Mean
DOWN
1
24
24
24
24
21
23
20
22
18
19
99th Percentile
DOWN
1
77
77
77
61
43
55
57
55
48
44
so2
Arithmetic Mean
DOWN
1
0.007
0.005
0.005
0.004
0.004
0.004
0.003
0.003
0.003
0.003
2nd Max. 24-hr
DOWN
1
0.050
0.036
0.027
0.025
0.019
0.022
0.022
0.018
0.019
0.020
FORT COLLINS-LOVELAND, CO
CO
2nd Max. 8-hr
DOWN
1
11.3
8.3
7.0
9.8
6.9
6.6
6.0
5.2
5.1
5.2
OZONE
4th Max. 8-hr
NS
2
0.08
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
2
0.10
0.09
0.08
0.09
0.09
0.09
0.10
0.09
0.09
0.09
PM10
Weighted Annual Mean
DOWN
1
28
29
23
25
23
22
22
22
20
16
99th Percentile
NS
1
84
60
52
59
41
62
51
57
61
40
FORT LAUDERDALE, FL
CO
2nd Max. 8-hr
NS
4
3.5
4.4
3.4
3.6
4.0
3.6
3.5
3.5
3.0
3.1
LEAD
Max. Quarterly Mean
NS
1
0.04
0.03
0.01
0.02
0.04
0.03
0.03
0.02
0.05
0.04
APPENDIX A: DATA TABLES 153
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
3
0.07
0.08
0.07
0.06
0.08
0.08
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
DCWN
3
0.11
0.11
0.09
0.09
0.10
0.10
0.09
0.09
0.09
0.09
FORT MYERS-CAPE CORAL, FL
OZONE
4th Max. 8-hr
DOWN
1
0.08
0.08
0.07
0.06
0.07
0.07
0.08
0.07
0.06
0.07
2nd Daily Max. 1-hr
DOWN
1
0.10
0.10
0.08
0.08
0.08
0.08
0.09
0.09
0.07
0.08
FORT SMITH, AR-OK
PM10
Weighted Annual Mean
DOWN
1
28
28
26
25
24
25
24
26
25
22
99th Percentile
NS
1
57
57
65
61
61
61
47
57
67
68
FORT WAYNE, IN
OZONE
4th Max. 8-hr
NS
1
0.10
0.09
0.08
0.09
0.09
0.08
0.10
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
1
0.12
0.12
0.09
0.10
0.09
0.10
0.11
0.11
0.11
0.10
PM10
Weighted Annual Mean
DOWN
1
29
29
27
27
23
23
24
24
17
20
99th Percentile
DOWN
1
75
75
81
57
51
63
50
54
49
50
FORT WORTH-ARLINGTON, TX
CO
2nd Max. 8-hr
DOWN
2
5.1
4.8
4.2
3.7
4.0
3.4
3.2
3.2
3.0
3.0
LEAD
Max. Quarterly Mean
DOWN
2
0.05
0.03
0.03
0.02
0.03
0.03
0.03
0.03
0.02
0.02
N02
Arithmetic Mean
UP
1
0.014
0.013
0.012
0.014
0.015
0.013
0.017
0.017
0.015
0.016
OZONE
4th Max. 8-hr
NS
2
0.10
0.10
0.10
0.11
0.08
0.09
0.10
0.10
0.09
0.09
2nd Daily Max. 1-hr
NS
2
0.14
0.13
0.14
0.15
0.12
0.11
0.13
0.14
0.13
0.12
PM10
Weighted Annual Mean
NS
3
25
24
24
23
21
21
20
24
25
22
99th Percentile
NS
3
64
63
52
76
57
64
43
62
61
55
so2
Arithmetic Mean
NS
1
0.002
0.001
0.002
0.002
0.003
0.001
0.002
0.001
0.001
0.001
2nd Max. 24-hr
NS
1
0.010
0.007
0.008
0.006
0.013
0.005
0.006
0.004
0.011
0.011
FRESNO, CA
CO
2nd Max. 8-hr
DOWN
3
6.1
6.0
6.0
6.6
4.9
4.4
5.3
4.4
4.4
3.7
N02
Arithmetic Mean
DOWN
3
0.021
0.022
0.021
0.022
0.020
0.021
0.020
0.020
0.019
0.019
OZONE
4th Max. 8-hr
NS
4
0.11
0.10
0.10
0.11
0.10
0.11
0.10
0.10
0.11
0.10
2nd Daily Max. 1-hr
DOWN
4
0.15
0.14
0.14
0.15
0.14
0.14
0.13
0.13
0.14
0.13
PM10
Weighted Annual Mean
DOWN
4
57
57
57
56
45
43
41
41
35
41
99th Percentile
DOWN
4
196
196
196
138
102
129
114
118
99
123
GADSDEN, AL
PM10
Weighted Annual Mean
DOWN
2
36
28
33
32
31
33
30
30
23
26
99th Percentile
NS
2
76
60
67
88
74
83
71
69
56
60
GALVESTON-TEXAS CITY,TX
LEAD
Max. Quarterly Mean
DOWN
1
0.04
0.03
0.02
0.02
0.02
0.03
0.02
0.03
0.02
0.02
OZONE
4th Max. 8-hr
NS
1
0.10
0.10
0.09
0.09
0.07
0.11
0.09
0.14
0.08
0.10
2nd Daily Max. 1-hr
NS
1
0.14
0.14
0.15
0.15
0.10
0.18
0.13
0.20
0.11
0.18
PM10
Weighted Annual Mean
DOWN
3
27
28
24
22
24
24
23
25
19
20
99th Percentile
NS
3
58
66
60
86
88
81
49
72
56
86
so2
Arithmetic Mean
NS
1
0.008
0.008
0.007
0.007
0.005
0.005
0.006
0.006
0.014
0.006
2nd Max. 24-hr
NS
1
0.045
0.045
0.063
0.050
0.039
0.056
0.052
0.089
0.067
0.053
GARY, IN
CO
2nd Max. 8-hr
NS
2
4.4
4.3
4.2
4.1
4.4
4.7
5.6
3.9
3.3
3.7
LEAD
Max. Quarterly Mean
DOWN
4
0.47
0.23
0.21
0.11
0.11
0.08
0.17
0.12
0.13
0.10
OZONE
4th Max. 8-hr
NS
4
0.12
0.08
0.08
0.09
0.08
0.07
0.08
0.10
0.09
0.09
2nd Daily Max. 1-hr
NS
4
0.15
0.10
0.10
0.11
0.11
0.09
0.11
0.12
0.11
0.11
PM10
Weighted Annual Mean
DOWN
8
35
33
33
29
26
24
26
25
21
21
99th Percentile
DOWN
8
105
88
88
73
72
66
63
59
50
53
so2
Arithmetic Mean
DOWN
5
0.010
0.011
0.010
0.008
0.007
0.007
0.006
0.005
0.005
0.005
2nd Max. 24-hr
DOWN
5
0.052
0.047
0.048
0.028
0.028
0.032
0.032
0.022
0.023
0.024
GLENS FALLS, NY
so2
Arithmetic Mean
DOWN
1
0.005
0.004
0.005
0.004
0.004
0.004
0.004
0.003
0.002
0.002
2nd Max. 24-hr
DOWN
1
0.040
0.023
0.040
0.020
0.017
0.018
0.027
0.011
0.013
0.013
GRAND FORKS, ND-MN
PM10
Weighted Annual Mean
DOWN
1
24
24
25
20
18
17
16
18
15
15
99th Percentile
DOWN
1
54
54
139
84
64
41
39
50
41
41
GRAND RAPIDS-MUSKEGON-HOLLAND, Ml
CO
2nd Max. 8-hr
NS
1
4.1
4.5
3.5
4.0
3.2
3.2
4.0
4.6
3.3
2.4
LEAD
Max. Quarterly Mean
DOWN
3
0.04
0.03
0.02
0.02
0.02
0.01
0.01
0.01
0.01
0.01
OZONE
4th Max. 8-hr
NS
3
0.11
0.09
0.10
0.10
0.08
0.08
0.09
0.09
0.09
0.08
2nd Daily Max. 1-hr
DOWN
3
0.14
0.13
0.12
0.12
0.10
0.10
0.11
0.12
0.12
0.10
PM10
Weighted Annual Mean
DOWN
2
28
29
30
26
35
22
27
21
20
19
99th Percentile
DOWN
2
78
80
79
65
129
63
73
66
53
47
so2
Arithmetic Mean
DOWN
1
0.004
0.004
0.004
0.004
0.003
0.003
0.003
0.002
0.002
0.002
2nd Max. 24-hr
DOWN
1
0.016
0.016
0.012
0.014
0.015
0.012
0.013
0.011
0.011
0.008
GREAT FALLS,
MT
CO
2nd Max. 8-hr
NS
1
5.6
5.6
5.6
6.6
5.8
6.9
4.8
6.2
5.4
6.4
PM10
Weighted Annual Mean
NS
1
20
20
24
21
21
21
21
18
19
20
99th Percentile
NS
1
69
69
109
124
53
61
48
52
69
62
GREELEY, CO
CO
2nd Max. 8-hr
DOWN
1
9.2
7.3
7.1
7.8
7.5
5.8
5.2
5.3
7.0
4.8
154 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan
Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
1
0.07
0.07
0.08
0.08
0.06
0.06
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
1
0.10
0.10
0.11
0.10
0.08
0.09
0.09
0.09
0.10
0.10
PM10
Weighted Annual Mean
DCWN
1
40
30
25
26
25
23
23
20
18
18
99th Percentile
DCWN
1
84
73
66
80
60
99
57
59
56
56
GREEN BAY,WI
so2
Arithmetic Mean
DOWN
1
0.007
0.006
0.005
0.005
0.004
0.003
0.003
0.004
0.003
0.003
2nd Max. 24-hr
DOWN
1
0.039
0.024
0.020
0.042
0.021
0.018
0.015
0.017
0.011
0.017
GREENSBORO
-WINSTON-SALEM—HIGH POINT, N
CO
2nd Max. 8-hr
DOWN
1
9.7
9.7
6.8
6.6
5.7
5.5
6.0
6.2
4.3
4.7
N02
Arithmetic Mean
NS
1
0.018
0.016
0.017
0.016
0.015
0.017
0.017
0.016
0.016
0.017
OZONE
4th Max. 8-hr
NS
3
0.11
0.08
0.09
0.08
0.08
0.09
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
3
0.14
0.10
0.12
0.10
0.10
0.11
0.11
0.11
0.11
0.11
PM10
Weighted Annual Mean
DOWN
3
34
32
31
31
27
27
25
26
24
24
99th Percentile
NS
3
76
66
58
83
53
59
46
64
46
67
so2
Arithmetic Mean
NS
1
0.007
0.007
0.008
0.007
0.006
0.006
0.007
0.007
0.007
0.007
2nd Max. 24-hr
NS
1
0.031
0.024
0.023
0.027
0.019
0.022
0.021
0.025
0.026
0.023
GREENVILLE-SPARTANBURG-ANDERSON, SC
LEAD
Max. Quarterly Mean
DOWN
3
0.06
0.04
0.04
0.04
0.02
0.02
0.02
0.02
0.01
0.01
OZONE
4th Max. 8-hr
NS
3
0.10
0.08
0.08
0.08
0.08
0.09
0.08
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
3
0.12
0.10
0.10
0.10
0.10
0.11
0.10
0.11
0.11
0.10
so2
Arithmetic Mean
NS
1
0.002
0.002
0.002
0.003
0.003
0.003
0.003
0.001
0.002
0.003
2nd Max. 24-hr
NS
1
0.011
0.011
0.011
0.017
0.013
0.012
0.016
0.007
0.012
0.014
GREENVILLE, NC
OZONE
4th Max. 8-hr
NS
1
0.10
0.08
0.08
0.08
0.08
0.09
0.08
0.08
0.09
0.10
2nd Daily Max. 1-hr
NS
1
0.12
0.10
0.10
0.09
0.10
0.11
0.09
0.10
0.10
0.12
HAMILTON-MIDDLETOWN, OH
OZONE
4th Max. 8-hr
NS
3
0.11
0.09
0.10
0.09
0.08
0.09
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
3
0.14
0.11
0.12
0.11
0.10
0.12
0.11
0.12
0.11
0.11
PM10
Weighted Annual Mean
NS
1
27
27
27
33
27
29
27
29
26
27
99th Percentile
NS
1
76
76
76
80
53
78
61
77
66
57
so2
Arithmetic Mean
DOWN
2
0.010
0.010
0.010
0.009
0.007
0.008
0.008
0.005
0.007
0.007
2nd Max. 24-hr
DOWN
2
0.041
0.040
0.037
0.040
0.033
0.035
0.038
0.019
0.025
0.034
HARRISBURG-LEBANON-CARLISLE, PA
N02
Arithmetic Mean
NS
2
0.014
0.014
0.013
0.014
0.013
0.011
0.015
0.014
0.015
0.013
OZONE
4th Max. 8-hr
NS
3
0.11
0.09
0.09
0.10
0.08
0.09
0.09
0.09
0.08
0.09
2nd Daily Max. 1-hr
NS
3
0.14
0.10
0.11
0.11
0.09
0.11
0.12
0.11
0.10
0.11
PM10
Weighted Annual Mean
NS
2
27
25
23
25
21
24
27
25
24
26
99th Percentile
NS
2
84
69
62
68
41
65
87
67
57
70
so2
Arithmetic Mean
NS
2
0.006
0.006
0.005
0.006
0.005
0.006
0.007
0.005
0.005
0.005
2nd Max. 24-hr
NS
2
0.024
0.029
0.021
0.021
0.022
0.021
0.035
0.017
0.021
0.022
HARTFORD, CT
CO
2nd Max. 8-hr
DOWN
2
8.3
6.7
6.7
6.1
6.1
5.6
6.4
5.8
5.0
4.8
N02
Arithmetic Mean
DOWN
1
0.020
0.020
0.019
0.020
0.017
0.018
0.020
0.017
0.016
0.018
OZONE
4th Max. 8-hr
DOWN
3
0.13
0.11
0.10
0.11
0.09
0.10
0.10
0.10
0.08
0.10
2nd Daily Max. 1-hr
DOWN
3
0.17
0.15
0.15
0.16
0.12
0.15
0.13
0.13
0.10
0.14
PM10
Weighted Annual Mean
DOWN
6
23
23
20
23
20
18
20
16
17
18
99th Percentile
NS
6
62
53
54
58
72
45
68
58
60
48
so2
Arithmetic Mean
DOWN
3
0.009
0.008
0.008
0.008
0.007
0.006
0.006
0.005
0.005
0.004
2nd Max. 24-hr
DOWN
3
0.040
0.039
0.033
0.034
0.029
0.021
0.029
0.020
0.020
0.023
HONOLULU, HI
CO
2nd Max. 8-hr
DOWN
2
3.3
3.4
2.9
2.6
2.8
3.1
3.1
2.5
2.4
2.3
LEAD
Max. Quarterly Mean
NS
2
0.01
0.03
0.01
0.01
0.01
0.01
0.00
0.00
0.01
0.02
OZONE
4th Max. 8-hr
UP
1
0.01
0.02
0.03
0.04
0.05
0.05
0.05
0.05
0.04
0.05
2nd Daily Max. 1-hr
NS
1
0.03
0.05
0.05
0.05
0.06
0.06
0.06
0.06
0.05
0.05
PM10
Weighted Annual Mean
NS
1
16
16
16
17
17
16
19
15
16
18
99th Percentile
DOWN
1
36
36
35
41
28
32
30
29
30
29
HOUMA, LA
OZONE
4th Max. 8-hr
NS
1
0.08
0.08
0.08
0.08
0.07
0.08
0.09
0.10
0.08
0.08
2nd Daily Max. 1-hr
NS
1
0.11
0.11
0.12
0.10
0.09
0.10
0.10
0.14
0.09
0.10
HOUSTON,TX
CO
2nd Max. 8-hr
DOWN
4
6.5
5.8
6.8
6.0
6.8
5.6
4.9
4.0
5.3
4.3
LEAD
Max. Quarterly Mean
DOWN
2
0.06
0.04
0.02
0.02
0.01
0.01
0.01
0.01
0.00
0.00
N02
Arithmetic Mean
DOWN
4
0.023
0.022
0.023
0.022
0.022
0.019
0.021
0.021
0.020
0.021
OZONE
4th Max. 8-hr
NS
10
0.11
0.11
0.12
0.10
0.10
0.09
0.10
0.12
0.10
0.11
2nd Daily Max. 1-hr
NS
10
0.18
0.18
0.19
0.17
0.16
0.16
0.15
0.17
0.16
0.17
PM10
Weighted Annual Mean
DOWN
5
32
32
31
31
30
30
31
30
26
29
99th Percentile
NS
5
69
69
71
96
94
82
69
82
53
93
so2
Arithmetic Mean
DOWN
7
0.005
0.005
0.005
0.005
0.005
0.005
0.004
0.004
0.004
0.003
2nd Max. 24-hr
DOWN
7
0.027
0.026
0.025
0.025
0.022
0.020
0.018
0.026
0.022
0.017
HUNTINGTON-ASHLAND, WV-KY-OH
CO
2nd Max. 8-hr
DOWN
1
3.9
5.5
4.7
4.4
4.1
3.8
5.2
3.8
3.7
3.8
LEAD
Max. Quarterly Mean
DOWN
2
0.13
0.06
0.04
0.04
0.04
0.04
0.03
0.04
0.03
0.04
APPENDIX A: DATA TABLES 155
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996
Sites
OZONE
4th Max. 8-hr
DCWN
3
0.11
0.09
0.09
0.10
0.08
0.09
0.09
0.09
0.08
2nd Daily Max. 1-hr
NS
3
0.13
0.12
0.11
0.13
0.10
0.11
0.13
0.12
0.10
PM10
Weighted Annual Mean
DCWN
4
37
35
35
33
30
29
32
31
28
99th Percentile
NS
4
91
89
99
63
68
63
68
76
66
so2
Arithmetic Mean
DCWN
7
0.016
0.014
0.013
0.012
0.010
0.011
0.010
0.009
0.008
2nd Max. 24-hr
DCWN
7
0.091
0.080
0.075
0.051
0.044
0.053
0.048
0.036
0.029
HUNTSVILLE, AL
CO
2nd Max. 8-hr
DOWN
1
5.0
5.2
4.2
4.1
4.2
4.0
3.5
3.6
3.0
OZONE
4th Max. 8-hr
NS
1
0.10
0.07
0.08
0.08
0.09
0.09
0.08
0.08
0.08
2nd Daily Max. 1-hr
NS
1
0.13
0.09
0.09
0.11
0.11
0.11
0.11
0.10
0.10
PM10
Weighted Annual Mean
DOWN
1
31
31
30
28
30
23
21
22
21
99th Percentile
DOWN
1
62
62
71
78
76
58
50
54
46
INDIANAPOLIS, IN
CO
2nd Max. 8-hr
DOWN
2
4.0
4.0
4.0
5.2
3.5
4.0
3.5
3.9
2.8
LEAD
Max. Quarterly Mean
DOWN
4
0.68
0.53
0.68
0.30
0.26
0.11
0.20
0.06
0.03
OZONE
4th Max. 8-hr
NS
6
0.10
0.09
0.09
0.09
0.08
0.08
0.09
0.09
0.10
2nd Daily Max. 1-hr
NS
6
0.12
0.11
0.10
0.10
0.09
0.10
0.11
0.11
0.12
PM10
Weighted Annual Mean
DOWN
13
34
35
33
31
28
28
28
28
23
99th Percentile
DOWN
13
82
82
89
76
65
68
68
67
54
so2
Arithmetic Mean
DOWN
10
0.011
0.011
0.009
0.009
0.008
0.009
0.007
0.005
0.006
2nd Max. 24-hr
DOWN
10
0.046
0.040
0.036
0.030
0.030
0.038
0.039
0.025
0.027
JACKSON, MS
OZONE
4th Max. 8-hr
NS
2
0.08
0.07
0.08
0.07
0.07
0.07
0.07
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.09
0.08
0.10
0.09
0.08
0.09
0.09
0.09
0.09
JACKSON, TN
PM10
Weighted Annual Mean
DOWN
2
32
31
28
27
27
23
23
25
22
99th Percentile
DOWN
2
67
62
73
68
74
58
66
51
52
JACKSONVILLE, FL
CO
2nd Max. 8-hr
DOWN
5
5.2
5.5
4.2
3.7
4.1
4.0
3.8
3.6
3.1
LEAD
Max. Quarterly Mean
DOWN
2
0.06
0.04
0.04
0.03
0.02
0.05
0.02
0.03
0.02
N02
Arithmetic Mean
NS
1
0.019
0.015
0.015
0.014
0.014
0.015
0.014
0.016
0.015
OZONE
4th Max. 8-hr
NS
2
0.08
0.08
0.08
0.07
0.08
0.08
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
2
0.11
0.11
0.11
0.09
0.10
0.11
0.10
0.11
0.09
PM10
Weighted Annual Mean
DOWN
3
34
36
34
32
26
27
26
27
24
99th Percentile
NS
3
72
63
62
64
69
66
51
63
57
so2
Arithmetic Mean
DOWN
5
0.005
0.004
0.004
0.003
0.003
0.003
0.003
0.003
0.003
2nd Max. 24-hr
DOWN
5
0.047
0.037
0.037
0.023
0.023
0.025
0.030
0.019
0.020
JAMESTOWN,
NY
so2
Arithmetic Mean
DOWN
1
0.014
0.014
0.012
0.013
0.011
0.011
0.010
0.009
0.008
2nd Max. 24-hr
NS
1
0.054
0.072
0.065
0.048
0.050
0.049
0.072
0.056
0.039
JERSEY CITY,
NJ
CO
2nd Max. 8-hr
DOWN
1
7.8
7.3
7.2
7.5
6.0
5.6
5.9
6.2
4.9
LEAD
Max. Quarterly Mean
DOWN
2
0.11
0.07
0.05
0.06
0.04
0.04
0.03
0.04
0.04
N02
Arithmetic Mean
DOWN
1
0.033
0.031
0.030
0.028
0.028
0.027
0.026
0.026
0.027
OZONE
4th Max. 8-hr
NS
1
0.14
0.10
0.11
0.12
0.09
0.10
0.10
0.10
0.09
2nd Daily Max. 1-hr
DOWN
1
0.20
0.12
0.18
0.14
0.11
0.13
0.12
0.13
0.12
PM10
Weighted Annual Mean
NS
3
31
33
31
32
26
27
32
25
27
99th Percentile
DOWN
3
86
83
86
77
59
69
93
65
70
so2
Arithmetic Mean
DOWN
2
0.015
0.014
0.013
0.012
0.010
0.009
0.009
0.007
0.008
2nd Max. 24-hr
DOWN
2
0.059
0.047
0.043
0.035
0.041
0.030
0.036
0.026
0.027
JOHNSON CITY-KINGS PORT-BRISTOL, TN-VA
CO
2nd Max. 8-hr
NS
1
3.7
3.7
3.4
3.3
3.0
6.5
3.4
3.0
3.0
N02
Arithmetic Mean
NS
1
0.019
0.019
0.019
0.019
0.018
0.017
0.017
0.018
0.018
OZONE
4th Max. 8-hr
NS
1
0.09
0.08
0.10
0.08
0.08
0.09
0.08
0.09
0.08
2nd Daily Max. 1-hr
NS
1
0.12
0.11
0.12
0.12
0.10
0.13
0.10
0.11
0.10
PM10
Weighted Annual Mean
DOWN
3
31
31
32
32
29
29
28
27
26
99th Percentile
NS
3
71
71
67
75
58
76
54
60
62
so2
Arithmetic Mean
NS
3
0.011
0.010
0.009
0.009
0.009
0.008
0.009
0.008
0.009
2nd Max. 24-hr
NS
3
0.049
0.053
0.044
0.044
0.039
0.042
0.045
0.039
0.044
JOHNSTOWN,
PA
CO
2nd Max. 8-hr
NS
1
4.3
4.1
3.7
4.8
4.4
4.2
4.1
3.5
4.8
LEAD
Max. Quarterly Mean
DOWN
1
0.30
0.31
0.16
0.19
0.14
0.06
0.05
0.06
0.06
N02
Arithmetic Mean
DOWN
1
0.019
0.019
0.018
0.019
0.018
0.017
0.018
0.015
0.018
OZONE
4th Max. 8-hr
NS
2
0.12
0.09
0.08
0.09
0.08
0.09
0.08
0.09
0.08
2nd Daily Max. 1-hr
NS
2
0.14
0.10
0.10
0.11
0.09
0.10
0.10
0.11
0.09
so2
Arithmetic Mean
DOWN
1
0.017
0.017
0.014
0.015
0.013
0.015
0.014
0.012
0.011
2nd Max. 24-hr
DOWN
1
0.054
0.089
0.046
0.043
0.052
0.049
0.080
0.042
0.034
KALAMAZOO-BATTLE CREEK, Ml
PM10
Weighted Annual Mean
DOWN
1
38
34
28
29
27
24
26
26
22
99th Percentile
DOWN
1
103
79
94
94
66
66
74
63
79
KANSAS CITY, MO-KS
CO
2nd Max. 8-hr
DOWN
4
4.7
5.1
4.7
4.1
3.8
4.3
4.5
3.5
3.4
0.08
0.11
30
73
3.1
0.09
0.10
21
49
3.2
0.04
0.09
0.10
23
53
0.006
0.026
23
48
2.6
0.02
0.014
0.08
0.10
24
55
0.003
0.017
4.3
0.04
0.026
0.11
0.12
26
55
0.008
0.025
3.5
0.018
0.08
0.11
25
63
0.009
0.050
2.7
0.06
0.016
0.08
0.10
0.009
0.030
23
49
3.4
156 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
LEAD
Max. Quarterly Mean
NS
5
0.17
0.06
0.03
0.03
0.02
0.02
0.02
0.02
0.03
0.10
N02
Arithmetic Mean
NS
3
0.010
0.011
0.011
0.010
0.010
0.009
0.010
0.010
0.012
0.010
OZONE
4th Max. 8-hr
NS
6
0.09
0.07
0.07
0.08
0.08
0.07
0.08
0.09
0.08
0.09
2nd Daily Max. 1-hr
NS
6
0.13
0.10
0.10
0.10
0.09
0.10
0.10
0.12
0.10
0.11
PM,„
Weighted Annual Mean
DCWN
7
33
34
31
32
30
30
30
24
33
26
99th Percentile
NS
7
76
90
83
70
78
89
71
68
87
63
so2
Arithmetic Mean
NS
5
0.005
0.004
0.003
0.003
0.003
0.003
0.003
0.003
0.004
0.004
2nd Max. 24-hr
NS
5
0.022
0.016
0.022
0.017
0.016
0.020
0.025
0.018
0.024
0.013
KENOSHA, Wl
OZONE
4th Max. 8-hr
NS
2
0.14
0.10
0.08
0.11
0.08
0.09
0.09
0.10
0.08
0.09
2nd Daily Max. 1-hr
NS
2
0.19
0.13
0.11
0.14
0.11
0.11
0.12
0.12
0.13
0.11
KNOXVILLE, TN
CO
2nd Max. 8-hr
DOWN
1
6.1
6.7
5.1
4.5
4.5
4.6
4.3
4.1
3.3
4.8
OZONE
4th Max. 8-hr
NS
4
0.10
0.07
0.09
0.08
0.08
0.09
0.09
0.09
0.09
0.10
2nd Daily Max. 1-hr
NS
4
0.12
0.09
0.11
0.10
0.10
0.11
0.11
0.12
0.11
0.12
PM10
Weighted Annual Mean
DOWN
8
33
32
32
34
30
30
32
31
31
26
99th Percentile
DOWN
8
72
66
76
68
63
68
61
61
68
58
so2
Arithmetic Mean
NS
2
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.007
0.006
2nd Max. 24-hr
UP
2
0.032
0.031
0.033
0.039
0.035
0.041
0.042
0.038
0.047
0.037
LAKE CHARLES, LA
OZONE
4th Max. 8-hr
NS
1
0.10
0.09
0.09
0.09
0.07
0.08
0.08
0.08
0.08
0.09
2nd Daily Max. 1-hr
DOWN
1
0.13
0.12
0.11
0.12
0.11
0.10
0.10
0.11
0.09
0.11
LAKELAND-WINTER HAVEN, FL
so2
Arithmetic Mean
UP
1
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.005
0.006
0.007
2nd Max. 24-hr
NS
1
0.016
0.016
0.022
0.016
0.018
0.019
0.016
0.014
0.021
0.017
LANCASTER, PA
CO
2nd Max. 8-hr
NS
1
3.4
4.1
3.4
2.6
2.6
3.0
3.8
2.4
2.6
3.3
LEAD
Max. Quarterly Mean
DOWN
1
0.07
0.05
0.06
0.04
0.04
0.04
0.04
0.04
0.04
0.04
N02
Arithmetic Mean
NS
1
0.020
0.018
0.017
0.018
0.015
0.015
0.019
0.016
0.017
0.016
OZONE
4th Max. 8-hr
NS
1
0.11
0.09
0.09
0.10
0.09
0.10
0.09
0.10
0.09
0.10
2nd Daily Max. 1-hr
NS
1
0.13
0.10
0.10
0.12
0.11
0.12
0.11
0.12
0.10
0.13
PM10
Weighted Annual Mean
NS
1
31
31
31
30
27
31
38
33
31
34
99th Percentile
UP
1
70
70
70
51
60
76
135
84
92
89
so2
Arithmetic Mean
NS
1
0.007
0.007
0.006
0.006
0.006
0.007
0.006
0.006
0.005
0.007
2nd Max. 24-hr
NS
1
0.028
0.037
0.028
0.023
0.023
0.026
0.030
0.018
0.021
0.023
LANSING-EAST LANSING, Ml
OZONE
4th Max. 8-hr
NS
2
0.10
0.08
0.08
0.08
0.08
0.08
0.08
0.08
0.08
0.08
2nd Daily Max. 1-hr
DOWN
2
0.12
0.10
0.10
0.11
0.09
0.10
0.09
0.10
0.09
0.09
LAS CRUCES, NM
CO
2nd Max. 8-hr
NS
2
5.0
4.5
4.6
5.0
3.8
6.0
4.1
3.7
3.7
3.9
LEAD
Max. Quarterly Mean
DOWN
2
0.18
0.16
0.17
0.15
0.13
0.12
0.05
0.09
0.07
0.07
OZONE
4th Max. 8-hr
NS
2
0.08
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.06
2nd Daily Max. 1-hr
NS
2
0.10
0.10
0.09
0.09
0.09
0.09
0.09
0.09
0.09
0.08
PM10
Weighted Annual Mean
NS
3
44
45
35
31
31
30
33
34
33
27
99th Percentile
NS
3
136
120
92
84
87
80
91
111
102
93
so2
Arithmetic Mean
DOWN
2
0.010
0.010
0.011
0.010
0.009
0.006
0.004
0.004
0.004
0.003
2nd Max. 24-hr
DOWN
2
0.068
0.061
0.056
0.055
0.052
0.055
0.023
0.021
0.030
0.014
LAS VEGAS,
NV-AZ
CO
2nd Max. 8-hr
DOWN
2
11.1
10.0
10.9
9.5
7.9
8.6
8.8
7.8
8.4
7.8
N02
Arithmetic Mean
DOWN
1
0.031
0.034
0.037
0.030
0.028
0.029
0.027
0.027
0.027
0.027
OZONE
4th Max. 8-hr
NS
3
0.08
0.08
0.07
0.07
0.08
0.08
0.08
0.07
0.08
0.07
2nd Daily Max. 1-hr
DOWN
3
0.11
0.10
0.10
0.09
0.09
0.10
0.09
0.09
0.09
0.09
PM10
Weighted Annual Mean
NS
1
37
60
69
59
48
43
47
47
53
60
99th Percentile
NS
1
84
187
362
110
103
117
117
126
113
121
LAWRENCE,
MA-NH
OZONE
4th Max. 8-hr
NS
1
0.11
0.08
0.07
0.09
0.07
0.08
0.08
0.07
0.08
0.08
2nd Daily Max. 1-hr
NS
1
0.13
0.11
0.09
0.12
0.09
0.10
0.10
0.08
0.09
0.10
PM10
Weighted Annual Mean
DOWN
1
21
21
21
18
19
18
16
13
14
15
99th Percentile
NS
1
41
41
41
45
74
57
54
29
35
42
so2
Arithmetic Mean
DOWN
2
0.008
0.009
0.008
0.007
0.008
0.008
0.006
0.006
0.005
0.005
2nd Max. 24-hr
DOWN
2
0.031
0.036
0.029
0.026
0.027
0.026
0.027
0.025
0.019
0.020
LAWTON, OK
PM10
Weighted Annual Mean
DOWN
1
32
32
30
27
26
27
28
25
28
26
99th Percentile
NS
1
104
74
100
71
53
59
62
52
70
71
LEWISTON-AUBURN, ME
PM10
Weighted Annual Mean
DOWN
1
25
25
25
29
24
24
20
20
20
21
99th Percentile
NS
1
59
59
59
66
81
70
56
58
52
54
so2
Arithmetic Mean
DOWN
1
0.007
0.008
0.007
0.006
0.005
0.007
0.006
0.004
0.004
0.004
2nd Max. 24-hr
DOWN
1
0.044
0.035
0.027
0.023
0.020
0.025
0.025
0.020
0.018
0.017
LEXINGTON, KY
CO
2nd Max. 8-hr
NS
1
5.4
5.6
3.7
4.9
3.8
6.5
4.2
3.0
3.1
5.2
N02
Arithmetic Mean
DOWN
1
0.018
0.019
0.017
0.016
0.016
0.017
0.016
0.017
0.014
0.014
APPENDIX A: DATA TABLES 157
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
2
0.11
0.09
0.08
0.08
0.06
0.08
0.09
0.08
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.12
0.11
0.10
0.09
0.08
0.10
0.10
0.11
0.09
0.09
PM10
Weighted Annual Mean
DOWN
2
30
30
28
28
24
25
27
26
24
23
99th Percentile
DOWN
2
82
82
67
61
62
58
83
63
58
56
so2
Arithmetic Mean
NS
1
0.007
0.006
0.006
0.008
0.007
0.007
0.008
0.006
0.006
0.006
2nd Max. 24-hr
NS
1
0.027
0.034
0.020
0.025
0.030
0.026
0.037
0.016
0.020
0.016
LIMA, OH
OZONE
4th Max. 8-hr
NS
1
0.09
0.09
0.08
0.09
0.08
0.09
0.09
0.09
0.09
0.08
2nd Daily Max. 1-hr
NS
1
0.11
0.10
0.10
0.10
0.10
0.10
0.10
0.11
0.11
0.09
so2
Arithmetic Mean
DOWN
1
0.006
0.006
0.005
0.006
0.004
0.005
0.004
0.003
0.003
0.003
2nd Max. 24-hr
NS
1
0.024
0.033
0.026
0.021
0.020
0.023
0.036
0.015
0.015
0.016
LINCOLN, NE
CO
2nd Max. 8-hr
DOWN
2
6.4
6.1
6.2
7.4
4.5
4.3
4.0
4.9
3.4
5.0
OZONE
4th Max. 8-hr
NS
1
0.07
0.06
0.06
0.06
0.07
0.05
0.06
0.06
0.05
0.05
2nd Daily Max. 1-hr
NS
1
0.08
0.06
0.07
0.07
0.07
0.06
0.08
0.07
0.06
0.06
PM10
Weighted Annual Mean
DOWN
2
29
33
29
30
25
26
28
25
28
24
99th Percentile
NS
2
63
65
62
100
51
54
49
67
80
55
LITTLE ROCK-NORTH LITTLE ROCK, AR
N02
Arithmetic Mean
NS
1
0.010
0.009
0.009
0.009
0.012
0.009
0.011
0.011
0.011
0.010
OZONE
4th Max. 8-hr
NS
2
0.09
0.07
0.08
0.08
0.08
0.08
0.08
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.11
0.09
0.10
0.10
0.09
0.10
0.09
0.11
0.10
0.10
PM10
Weighted Annual Mean
DOWN
4
30
29
29
25
28
27
27
29
26
25
99th Percentile
NS
4
73
80
69
55
74
64
62
65
52
78
so2
Arithmetic Mean
NS
1
0.002
0.002
0.003
0.003
0.005
0.006
0.003
0.002
0.002
0.002
2nd Max. 24-hr
DOWN
1
0.016
0.010
0.014
0.012
0.012
0.017
0.009
0.008
0.009
0.006
LONGVIEW-MARSHALL,TX
OZONE
4th Max. 8-hr
NS
1
0.09
0.09
0.09
0.08
0.08
0.09
0.08
0.10
0.08
0.09
2nd Daily Max. 1-hr
NS
1
0.12
0.10
0.13
0.11
0.10
0.11
0.10
0.15
0.11
0.12
LOS ANGELES-LONG BEACH, CA
CO
2nd Max. 8-hr
DOWN
13
10.1
9.6
9.0
8.8
7.8
6.8
8.0
7.5
6.8
6.6
LEAD
Max. Quarterly Mean
DOWN
6
0.15
0.09
0.09
0.10
0.08
0.06
0.06
0.05
0.05
0.05
N02
Arithmetic Mean
DOWN
13
0.046
0.044
0.041
0.041
0.038
0.036
0.039
0.038
0.035
0.033
OZONE
4th Max. 8-hr
DOWN
14
0.14
0.14
0.12
0.13
0.13
0.12
0.11
0.11
0.10
0.09
2nd Daily Max. 1-hr
DOWN
14
0.23
0.22
0.19
0.19
0.20
0.17
0.17
0.15
0.14
0.12
PM10
Weighted Annual Mean
DOWN
9
57
57
49
53
41
40
39
39
38
39
99th Percentile
DOWN
9
149
155
152
192
104
91
103
120
104
88
so2
Arithmetic Mean
DOWN
4
0.005
0.004
0.003
0.003
0.004
0.003
0.003
0.003
0.003
0.003
2nd Max. 24-hr
DOWN
4
0.019
0.015
0.012
0.013
0.015
0.011
0.008
0.008
0.008
0.007
LOUISVILLE, KY-IN
CO
2nd Max. 8-hr
DOWN
3
5.9
6.0
5.9
5.9
4.2
4.6
5.1
3.8
3.3
4.5
LEAD
Max. Quarterly Mean
DOWN
2
0.07
0.05
0.04
0.05
0.05
0.05
0.02
0.05
0.02
0.02
OZONE
4th Max. 8-hr
NS
4
0.11
0.08
0.08
0.09
0.07
0.09
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
4
0.16
0.11
0.11
0.12
0.09
0.13
0.12
0.12
0.11
0.12
PM10
Weighted Annual Mean
DOWN
6
38
35
34
33
30
29
30
29
26
29
99th Percentile
NS
6
90
77
74
67
62
70
104
68
72
78
so2
Arithmetic Mean
DOWN
4
0.010
0.010
0.010
0.010
0.009
0.010
0.010
0.008
0.007
0.006
2nd Max. 24-hr
DOWN
4
0.044
0.055
0.041
0.037
0.034
0.035
0.040
0.028
0.031
0.031
LOWELL, MA-NH
CO
2nd Max. 8-hr
NS
1
6.4
5.3
7.3
5.8
5.9
5.1
6.5
7.8
4.5
3.6
LUBBOCK, TX
PM10
Weighted Annual Mean
DOWN
1
36
34
24
25
22
20
23
21
22
17
99th Percentile
NS
1
100
94
61
66
58
56
81
64
85
38
LYNCHBURG, VA
PM10
Weighted Annual Mean
DOWN
1
31
30
24
28
24
26
23
24
23
23
99th Percentile
NS
1
80
58
53
89
50
68
51
55
46
55
MADISON,Wl
PM10
Weighted Annual Mean
DOWN
1
34
34
24
25
22
21
22
23
20
20
99th Percentile
DOWN
1
90
90
54
61
42
85
61
64
52
37
MANSFIELD, OH
PM10
Weighted Annual Mean
NS
1
27
27
27
27
26
28
29
25
24
23
99th Percentile
NS
1
67
67
67
71
68
66
58
61
68
63
MEDFORD-ASHLAND, OR
CO
2nd Max. 8-hr
DOWN
1
11.3
11.0
8.2
8.1
6.4
6.9
6.2
5.3
6.4
5.7
LEAD
Max. Quarterly Mean
DOWN
1
0.05
0.04
0.02
0.03
0.02
0.02
0.02
0.02
0.02
0.02
PM10
Weighted Annual Mean
DOWN
3
54
54
42
40
36
35
33
26
24
26
99th Percentile
DOWN
3
171
179
117
144
102
88
78
59
66
74
MELBOURNE-TITUSVILLE-PALM BAY, FL
OZONE
4th Max. 8-hr
DOWN
2
0.08
0.08
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
2
0.10
0.10
0.08
0.09
0.08
0.09
0.09
0.08
0.09
0.09
MEMPHIS,TN-AR-MS
CO
2nd Max. 8-hr
DOWN
5
6.4
8.2
7.5
6.1
7.7
7.6
7.3
6.0
5.3
5.0
LEAD
Max. Quarterly Mean
DOWN
3
1.01
1.03
0.98
0.64
0.77
0.83
0.80
0.54
0.96
0.36
158 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
N02
Arithmetic Mean
NS
1
0.032
0.026
0.023
0.024
0.026
0.026
0.027
0.027
0.024
0.028
OZONE
4th Max. 8-hr
NS
3
0.10
0.08
0.09
0.09
0.08
0.09
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
3
0.13
0.11
0.12
0.11
0.11
0.11
0.11
0.12
0.13
0.12
PM,„
Weighted Annual Mean
DCWN
2
31
31
31
27
28
29
27
27
27
26
99th Percentile
NS
2
69
68
76
67
59
69
69
65
73
63
so2
Arithmetic Mean
DCWN
2
0.006
0.007
0.007
0.007
0.007
0.006
0.005
0.004
0.003
0.003
2nd Max. 24-hr
DCWN
2
0.029
0.029
0.027
0.025
0.031
0.029
0.025
0.019
0.011
0.011
MERCED, CA
PM10
Weighted Annual Mean
DOWN
1
52
52
53
52
46
43
39
39
31
31
99th Percentile
DOWN
1
114
148
211
145
98
121
131
100
61
61
MIAMI, FL
CO
2nd Max. 8-hr
DOWN
2
4.8
7.3
6.0
7.2
6.2
5.3
4.4
4.9
4.5
3.8
LEAD
Max. Quarterly Mean
DOWN
2
0.05
0.05
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.01
N02
Arithmetic Mean
NS
2
0.012
0.013
0.011
0.011
0.011
0.012
0.010
0.011
0.011
0.012
OZONE
4th Max. 8-hr
NS
4
0.08
0.08
0.07
0.06
0.07
0.08
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
4
0.11
0.11
0.10
0.09
0.10
0.10
0.09
0.09
0.09
0.10
PM10
Weighted Annual Mean
DOWN
3
28
27
28
26
27
27
26
24
25
23
99th Percentile
UP
3
52
50
53
61
71
95
74
73
63
66
so2
Arithmetic Mean
UP
1
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.002
0.002
0.001
2nd Max. 24-hr
UP
1
0.002
0.003
0.003
0.003
0.005
0.004
0.004
0.004
0.005
0.004
MIDDLESEX-SOMERSET-HUNTERDON, NJ
CO
2nd Max. 8-hr
DOWN
1
5.3
5.4
5.4
4.2
3.9
3.7
4.3
5.3
3.3
3.8
LEAD
Max. Quarterly Mean
DOWN
1
0.38
0.38
0.30
1.15
1.22
0.33
0.12
0.07
0.06
0.08
OZONE
4th Max. 8-hr
NS
1
0.13
0.10
0.11
0.11
0.09
0.10
0.09
0.10
0.09
0.10
2nd Daily Max. 1-hr
DOWN
1
0.16
0.13
0.14
0.12
0.12
0.12
0.11
0.12
0.11
0.12
PM10
Weighted Annual Mean
DOWN
1
34
34
29
30
25
25
27
22
25
25
99th Percentile
DOWN
1
67
67
60
72
55
62
68
59
46
46
so2
Arithmetic Mean
DOWN
1
0.012
0.010
0.007
0.007
0.006
0.005
0.005
0.004
0.005
0.005
2nd Max. 24-hr
DOWN
1
0.043
0.037
0.032
0.025
0.026
0.018
0.028
0.018
0.024
0.019
MILWAUKEE-WAUKESHA, Wl
CO
2nd Max. 8-hr
DOWN
6
4.2
3.9
4.5
3.7
3.2
4.1
4.4
2.9
2.0
2.0
LEAD
Max. Quarterly Mean
DOWN
1
0.10
0.06
0.08
0.06
0.05
0.04
0.03
0.05
0.03
0.03
N02
Arithmetic Mean
DOWN
2
0.023
0.024
0.022
0.021
0.021
0.020
0.021
0.021
0.020
0.020
OZONE
4th Max. 8-hr
NS
6
0.11
0.10
0.08
0.09
0.08
0.08
0.08
0.10
0.08
0.08
2nd Daily Max. 1-hr
NS
6
0.15
0.13
0.11
0.14
0.10
0.10
0.12
0.12
0.11
0.12
PM10
Weighted Annual Mean
DOWN
4
32
35
33
29
26
26
28
27
25
24
99th Percentile
DOWN
4
94
86
80
83
57
77
81
68
57
54
so2
Arithmetic Mean
DOWN
2
0.006
0.006
0.006
0.006
0.005
0.003
0.004
0.003
0.004
0.004
2nd Max. 24-hr
DOWN
2
0.035
0.030
0.039
0.034
0.026
0.024
0.027
0.023
0.025
0.025
MINNEAPOLIS-ST. PAUL, MN-WI
CO
2nd Max. 8-hr
DOWN
3
7.7
9.0
6.5
7.2
5.9
5.2
6.4
6.0
5.1
4.5
LEAD
Max. Quarterly Mean
DOWN
3
0.55
0.38
0.77
0.31
0.25
0.12
0.07
0.23
0.12
0.09
N02
Arithmetic Mean
NS
2
0.013
0.013
0.013
0.012
0.012
0.013
0.014
0.013
0.014
0.013
OZONE
4th Max. 8-hr
NS
4
0.08
0.07
0.07
0.07
0.08
0.06
0.07
0.08
0.07
0.07
2nd Daily Max. 1-hr
NS
4
0.10
0.09
0.09
0.08
0.09
0.08
0.08
0.10
0.09
0.09
PM10
Weighted Annual Mean
DOWN
9
31
30
28
26
22
22
23
23
23
22
99th Percentile
DOWN
9
87
81
99
63
71
58
59
58
71
49
so2
Arithmetic Mean
DOWN
8
0.004
0.004
0.004
0.004
0.003
0.003
0.003
0.002
0.002
0.002
2nd Max. 24-hr
DOWN
8
0.020
0.021
0.020
0.021
0.019
0.015
0.014
0.012
0.013
0.013
MOBILE, AL
OZONE
4th Max. 8-hr
NS
2
0.08
0.07
0.08
0.05
0.07
0.07
0.07
0.08
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.10
0.09
0.10
0.07
0.10
0.09
0.09
0.11
0.10
0.11
PM10
Weighted Annual Mean
DOWN
4
35
31
31
32
34
32
31
29
25
26
99th Percentile
NS
4
80
76
61
70
93
77
61
57
53
62
so2
Arithmetic Mean
NS
1
0.008
0.008
0.008
0.009
0.010
0.010
0.011
0.009
0.009
0.008
2nd Max. 24-hr
NS
1
0.054
0.064
0.038
0.050
0.054
0.066
0.052
0.053
0.070
0.049
MODESTO, CA
CO
2nd Max. 8-hr
DOWN
1
9.7
11.8
10.5
9.4
5.9
6.6
6.3
5.4
5.6
4.2
LEAD
Max. Quarterly Mean
DOWN
1
0.04
0.04
0.04
0.04
0.02
0.02
0.02
0.01
0.01
0.01
N02
Arithmetic Mean
DOWN
1
0.027
0.027
0.026
0.024
0.022
0.024
0.023
0.022
0.022
0.021
OZONE
4th Max. 8-hr
NS
1
0.09
0.09
0.10
0.09
0.08
0.09
0.09
0.10
0.09
0.08
2nd Daily Max. 1-hr
NS
1
0.12
0.11
0.12
0.11
0.11
0.11
0.12
0.13
0.13
0.11
PM10
Weighted Annual Mean
DOWN
2
46
46
44
48
39
40
37
34
28
31
99th Percentile
DOWN
2
151
151
162
142
136
134
136
99
101
103
MONMOUTH-OCEAN, NJ
CO
2nd Max. 8-hr
DOWN
2
6.6
6.1
5.7
5.5
4.7
5.3
4.9
3.8
4.4
3.7
OZONE
4th Max. 8-hr
NS
1
0.11
0.11
0.11
0.11
0.09
0.10
0.08
0.11
0.09
0.10
2nd Daily Max. 1-hr
NS
1
0.14
0.14
0.14
0.15
0.14
0.13
0.11
0.15
0.12
0.13
MONTGOMERY, AL
OZONE
4th Max. 8-hr
NS
1
0.08
0.08
0.08
0.07
0.08
0.09
0.08
0.09
0.08
0.07
2nd Daily Max. 1-hr
NS
1
0.10
0.10
0.10
0.09
0.10
0.11
0.10
0.10
0.10
0.09
APPENDIX A: DATA TABLES 159
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
Sites
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
PM,„
NASHUA, NH
CO
N02
OZONE
PM10
SO,
Weighted Annual Mean
99th Percentile
2nd Max. 8-hr
Arithmetic Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
Weighted Annual Mean
99th Percentile
Arithmetic Mean
2nd Max. 24-hr
NASHVILLE, TN
CO 2nd Max. 8-hr
LEAD Max. Quarterly Mean
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
NASSAU-SUFFOLK, NY
CO 2nd Max. 8-hr
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
S02 Arithmetic Mean
2nd Max. 24-hr
NEW BEDFORD, MA
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
NEW HAVEN-MERIDEN, CT
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
NEW LONDON-NORWICH, CT-RI
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
NEW ORLEANS, LA
CO
LEAD
N02
OZONE
PM10
so2
NEW YORK, NY
CO
LEAD
N02
OZONE
PM„
so2
NEWARK, NJ
CO
LEAD
N02
2nd Max. 8-hr
Max. Quarterly Mean
Arithmetic Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
Weighted Annual Mean
99th Percentile
Arithmetic Mean
2nd Max. 24-hr
2nd Max. 8-hr
Max. Quarterly Mean
Arithmetic Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
Weighted Annual Mean
99th Percentile
Arithmetic Mean
2nd Max. 24-hr
2nd Max. 8-hr
Max. Quarterly Mean
Arithmetic Mean
NS
NS
NS
DOWN
NS
NS
DOWN
NS
DOWN
DOWN
DOWN
NS
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
NS
DOWN
UP
DOWN
NS
NS
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
NS
NS
NS
DOWN
NS
DOWN
NS
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
1
1
2
1
2
2
5
5
3
3
3
4
1
7
7
5
5
4
5
1
1
1
1
2
2
1
1
1
1
1
2
2
7
7
2
2
1
1
2
2
1
1
2
1
2
5
5
1
1
2
2
4
3
1
5
5
12
12
7
7
3
1
4
23
53
5.7
0.024
0.10
0.14
22
65
0.008
0.044
6.5
1.29
0.012
0.10
0.12
38
80
0.008
0.047
9.1
0.033
0.12
0.16
0.008
0.056
0.13
0.16
23
42
0.029
0.12
0.17
31
71
0.015
0.071
0.12
0.15
23
55
0.009
0.047
6.1
0.10
0.019
0.09
0.11
26
57
0.004
0.017
8.3
0.14
0.049
0.12
0.17
33
74
0.015
0.060
7.3
0.83
0.033
23
53
6.2
0.022
0.07
0.09
22
53
0.008
0.040
7.4
0.66
0.012
0.08
0.10
37
79
0.008
0.053
27
62
7.1
0.019
0.08
0.10
18
50
0.007
0.036
5.9
1.45
0.012
0.09
0.11
36
78
0.009
0.050
0.11
0.15
0.09
0.12
23
42
0.028
0.10
0.15
31
69
0.012
0.071
0.12
0.14
23
55
0.008
0.027
6.1
0.09
0.017
0.08
0.10
31
68
0.003
0.017
7.9
0.08
0.049
0.09
0.12
34
78
0.015
0.060
7.6
0.41
0.030
26
61
6.9
0.016
0.09
0.10
19
53
0.005
0.024
5.0
1.21
0.010
0.08
0.10
35
75
0.009
0.056
6.5 7.2 6.6
0.029 0.028 0.029
0.11
0.14
0.010 0.009 0.009
0.045 0.045 0.039
0.11
0.18
0.10
0.13
23
42
0.027
0.10
0.13
29
86
0.010
0.045
0.11
0.16
21
56
0.008
0.029
4.9
0.05
0.016
0.08
0.10
27
75
0.003
0.013
7.1
0.09
0.046
0.10
0.13
31
77
0.014
0.054
0.10
0.13
20
65
0.028
0.12
0.16
32
87
0.010
0.055
0.11
0.14
24
73
0.007
0.027
4.2
0.03
0.015
0.07
0.10
26
59
0.004
0.023
6.6
0.08
0.047
0.11
0.14
30
78
0.014
0.048
24
49
6.8
0.015
0.08
0.10
17
80
0.006
0.025
5.5
1.05
0.014
0.08
0.10
31
62
0.006
0.025
5.6
0.026
0.09
0.13
0.008
0.039
0.09
0.11
17
45
0.025
0.08
0.12
26
69
0.009
0.042
0.09
0.12
20
71
0.006
0.025
5.4
0.03
0.017
0.08
0.10
27
72
0.005
0.018
6.0
0.06
0.036
0.08
0.12
27
62
0.013
0.051
23
70
5.2
0.016
0.08
0.11
17
43
0.006
0.022
6.4
0.91
0.012
0.08
0.10
31
81
0.007
0.043
5.6
0.026
0.10
0.13
0.008
0.033
0.07
0.09
17
46
0.027
0.09
0.14
27
72
0.008
0.038
0.10
0.13
18
48
0.006
0.019
5.1
0.02
0.016
0.08
0.10
25
85
0.005
0.019
5.1
0.09
0.043
0.09
0.12
26
62
0.012
0.039
25
47
7.5
0.015
0.08
0.10
15
43
0.006
0.028
5.4
0.98
0.020
0.08
0.10
30
71
0.006
0.038
5.4
0.028
0.09
0.13
0.007
0.037
0.08
0.10
19
50
0.030
0.09
0.14
28
81
0.008
0.049
0.09
0.12
22
55
0.005
0.029
4.6
0.02
0.015
0.08
0.11
25
53
0.005
0.021
5.8
0.08
0.046
0.09
0.12
28
79
0.013
0.054
26
75
6.8
0.014
0.08
0.10
14
46
0.005
0.023
4.8
1.93
0.014
0.09
0.10
31
67
0.004
0.024
5.0
0.025
0.11
0.15
0.005
0.030
0.11
0.14
14
46
0.025
0.10
0.14
23
71
0.006
0.031
0.10
0.14
17
63
0.005
0.017
3.6
0.03
0.016
0.08
0.11
24
55
0.005
0.019
6.5
0.07
0.042
0.10
0.12
26
73
0.010
0.038
23
68
7.7
0.019
0.08
0.10
16
43
0.005
0.021
3.9
0.62
0.012
0.09
0.11
28
64
0.005
0.033
4.9
0.026
0.09
0.12
0.007
0.028
0.09
0.12
16
51
0.026
0.08
0.11
22
63
0.006
0.027
0.10
0.12
19
69
0.005
0.016
4.0
0.02
0.015
0.08
0.10
22
58
0.005
0.025
4.5
0.08
0.042
0.09
0.12
27
69
0.010
0.040
7.1 8.3
0.39 1.04
0.029 0.028
5.6 4.9
0.44 0.23
0.030 0.028
7.7 6.0 5.1
0.30 0.23 0.23
0.030 0.028 0.029
24
57
4.7
0.016
0.09
0.11
18
53
0.006
0.025
4.7
0.65
0.012
0.09
0.11
28
61
0.005
0.037
4.7
0.025
0.11
0.14
0.006
0.029
0.09
0.12
18
51
0.024
0.10
0.14
22
57
0.005
0.028
0.11
0.15
18
59
0.004
0.022
3.3
0.02
0.014
0.08
0.10
25
100
0.004
0.016
3.6
0.08
0.040
0.10
0.13
27
77
0.009
0.033
4.6
0.23
0.028
160 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan
Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
2
0.13
0.09
0.10
0.10
0.09
0.09
0.09
0.10
0.09
0.10
2nd Daily Max. 1-hr
DOWN
2
0.18
0.12
0.13
0.12
0.10
0.12
0.11
0.12
0.11
0.11
PM10
Weighted Annual Mean
NS
3
35
35
31
30
29
30
35
28
31
31
99th Percentile
NS
3
84
80
73
72
60
77
103
72
76
87
so2
Arithmetic Mean
DOWN
4
0.012
0.012
0.010
0.010
0.009
0.007
0.008
0.006
0.006
0.006
2nd Max. 24-hr
DOWN
4
0.050
0.047
0.040
0.035
0.040
0.025
0.033
0.025
0.027
0.023
NEWBURGH, NY-PA
LEAD
Max. Quarterly Mean
DOWN
2
1.33
1.42
1.01
0.66
0.58
0.34
0.08
0.08
0.06
0.20
NORFOLK-VA BEACH-NEWPORT NEWS,VA-N
CO
2nd Max. 8-hr
DOWN
3
5.5
5.2
4.5
5.1
4.3
5.0
5.4
4.3
4.3
4.0
LEAD
Max. Quarterly Mean
DOWN
1
0.10
0.12
0.18
0.03
0.03
0.03
0.02
0.03
0.03
0.03
N02
Arithmetic Mean
NS
1
0.020
0.020
0.019
0.020
0.020
0.021
0.019
0.018
0.018
0.019
OZONE
4th Max. 8-hr
NS
2
0.11
0.08
0.09
0.08
0.09
0.10
0.08
0.08
0.08
0.09
2nd Daily Max. 1-hr
NS
2
0.13
0.10
0.11
0.10
0.13
0.13
0.10
0.10
0.10
0.11
PM10
Weighted Annual Mean
DOWN
4
28
27
26
26
23
23
20
21
22
22
99th Percentile
DOWN
4
61
64
70
58
52
59
49
44
49
53
so2
Arithmetic Mean
DOWN
2
0.008
0.007
0.007
0.007
0.006
0.007
0.007
0.006
0.006
0.006
2nd Max. 24-hr
NS
2
0.032
0.033
0.025
0.022
0.024
0.026
0.024
0.022
0.022
0.025
OAKLAND, CA
CO
2nd Max. 8-hr
DOWN
6
4.9
4.9
4.8
4.8
4.0
3.4
3.6
2.7
2.9
2.9
LEAD
Max. Quarterly Mean
DOWN
4
0.15
0.13
0.08
0.10
0.02
0.02
0.02
0.02
0.01
0.01
N02
Arithmetic Mean
DOWN
2
0.023
0.022
0.021
0.022
0.020
0.020
0.020
0.019
0.018
0.017
OZONE
4th Max. 8-hr
NS
7
0.08
0.07
0.06
0.06
0.06
0.07
0.07
0.08
0.07
0.06
2nd Daily Max. 1-hr
NS
7
0.11
0.10
0.09
0.09
0.09
0.10
0.10
0.13
0.10
0.09
PM10
Weighted Annual Mean
DOWN
3
30
31
30
33
27
25
25
22
22
23
99th Percentile
DOWN
3
87
100
127
115
82
79
87
53
58
56
so2
Arithmetic Mean
NS
3
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
2nd Max. 24-hr
DOWN
3
0.010
0.013
0.011
0.010
0.009
0.010
0.007
0.007
0.007
0.008
OKLAHOMA CITY, OK
CO
2nd Max. 8-hr
NS
3
5.2
6.4
5.4
4.7
4.8
6.1
5.2
5.0
5.1
5.1
LEAD
Max. Quarterly Mean
DOWN
2
0.07
0.05
0.02
0.03
0.02
0.02
0.01
0.01
0.00
0.00
N02
Arithmetic Mean
NS
3
0.018
0.013
0.012
0.011
0.011
0.011
0.012
0.012
0.012
0.013
OZONE
4th Max. 8-hr
NS
4
0.08
0.08
0.08
0.08
0.07
0.07
0.08
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
4
0.10
0.10
0.10
0.10
0.09
0.09
0.09
0.11
0.09
0.10
PM10
Weighted Annual Mean
NS
4
24
23
22
22
22
21
21
21
24
22
99th Percentile
NS
4
59
59
55
53
65
49
49
57
64
55
so2
Arithmetic Mean
NS
1
0.010
0.007
0.004
0.002
0.002
0.003
0.004
0.002
0.002
0.002
2nd Max. 24-hr
DOWN
1
0.041
0.015
0.019
0.005
0.009
0.008
0.007
0.006
0.006
0.006
OLYMPIA, WA
PM10
Weighted Annual Mean
DOWN
1
35
28
24
25
24
24
17
17
16
16
99th Percentile
DOWN
1
169
118
86
99
78
78
63
65
53
58
OMAHA, NE-IA
CO
2nd Max. 8-hr
NS
2
5.5
4.8
5.2
5.8
5.9
5.3
4.0
5.5
4.9
4.2
LEAD
Max. Quarterly Mean
DOWN
5
0.79
0.67
0.54
0.44
0.69
0.55
0.73
0.49
0.38
0.21
OZONE
4th Max. 8-hr
DOWN
3
0.08
0.07
0.06
0.06
0.06
0.05
0.06
0.06
0.06
0.06
2nd Daily Max. 1-hr
DOWN
3
0.09
0.08
0.07
0.08
0.08
0.06
0.07
0.08
0.07
0.07
PM10
Weighted Annual Mean
DOWN
7
42
42
37
36
36
31
33
30
33
33
99th Percentile
DOWN
7
112
110
113
86
107
88
90
91
85
90
ORANGE COUNTY, CA
CO
2nd Max. 8-hr
DOWN
4
8.8
9.0
8.3
7.0
7.5
5.8
7.3
5.7
5.8
4.8
LEAD
Max. Quarterly Mean
DOWN
1
0.09
0.08
0.06
0.06
0.03
0.05
0.04
0.04
0.04
0.04
N02
Arithmetic Mean
DOWN
3
0.038
0.038
0.039
0.038
0.034
0.032
0.034
0.033
0.029
0.028
OZONE
4th Max. 8-hr
DOWN
3
0.12
0.13
0.11
0.10
0.11
0.10
0.11
0.09
0.09
0.08
2nd Daily Max. 1-hr
DOWN
3
0.22
0.23
0.19
0.19
0.18
0.16
0.17
0.13
0.13
0.11
PM10
Weighted Annual Mean
DOWN
2
45
45
45
41
37
36
36
41
33
37
99th Percentile
NS
2
123
123
123
120
86
104
99
147
90
89
so2
Arithmetic Mean
NS
2
0.003
0.002
0.002
0.002
0.002
0.002
0.002
0.003
0.002
0.002
2nd Max. 24-hr
DOWN
2
0.011
0.009
0.007
0.010
0.008
0.007
0.006
0.005
0.004
0.005
ORLANDO, FL
CO
2nd Max. 8-hr
DOWN
2
4.5
4.3
4.5
3.6
3.9
3.8
3.6
3.3
3.3
3.6
LEAD
Max. Quarterly Mean
DOWN
2
0.05
0.02
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
N02
Arithmetic Mean
NS
1
0.013
0.013
0.012
0.012
0.011
0.012
0.011
0.010
0.013
0.013
OZONE
4th Max. 8-hr
NS
3
0.08
0.09
0.08
0.07
0.08
0.08
0.08
0.08
0.07
0.08
2nd Daily Max. 1-hr
NS
3
0.10
0.11
0.11
0.09
0.10
0.10
0.10
0.10
0.10
0.10
PM10
Weighted Annual Mean
DOWN
3
28
27
27
27
24
24
23
22
23
23
99th Percentile
NS
3
56
53
48
54
57
99
91
38
77
47
so2
Arithmetic Mean
NS
1
0.003
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
2nd Max. 24-hr
NS
1
0.010
0.006
0.011
0.007
0.007
0.011
0.012
0.006
0.008
0.006
OWENSBORO, KY
CO
2nd Max. 8-hr
NS
1
6.4
5.9
5.4
3.8
4.5
5.5
3.9
4.2
4.2
4.2
N02
Arithmetic Mean
NS
1
0.015
0.014
0.011
0.011
0.012
0.012
0.012
0.013
0.011
0.012
APPENDIX A: DATA TABLES 161
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan
Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
1
0.11
0.08
0.09
0.08
0.08
0.08
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
1
0.14
0.10
0.11
0.09
0.09
0.11
0.11
0.11
0.11
0.11
PM10
Weighted Annual Mean
DCWN
1
33
33
29
29
27
25
30
29
24
26
99th Percentile
NS
1
82
82
71
62
52
61
106
77
61
56
so2
Arithmetic Mean
DCWN
1
0.010
0.010
0.009
0.009
0.009
0.009
0.009
0.007
0.007
0.007
2nd Max. 24-hr
DCWN
1
0.040
0.053
0.038
0.044
0.053
0.050
0.035
0.028
0.020
0.027
PARKERSBURG-MARIETTA,WV-OH
LEAD
Max. Quarterly Mean
NS
1
0.04
0.04
0.02
0.02
0.02
0.02
0.01
0.02
0.02
0.02
OZONE
4th Max. 8-hr
NS
1
0.12
0.09
0.08
0.10
0.07
0.08
0.09
0.10
0.09
0.09
2nd Daily Max. 1-hr
NS
1
0.15
0.12
0.11
0.12
0.10
0.10
0.11
0.12
0.11
0.11
so2
Arithmetic Mean
NS
1
0.015
0.016
0.014
0.014
0.014
0.014
0.017
0.010
0.010
0.010
2nd Max. 24-hr
NS
1
0.076
0.076
0.064
0.060
0.059
0.065
0.084
0.041
0.046
0.052
PENSACOLA, I
FL
OZONE
4th Max. 8-hr
NS
2
0.09
0.08
0.09
0.08
0.09
0.08
0.09
0.08
0.08
0.09
2nd Daily Max. 1-hr
NS
2
0.10
0.09
0.11
0.10
0.10
0.10
0.11
0.12
0.10
0.11
so2
Arithmetic Mean
DOWN
1
0.007
0.007
0.008
0.006
0.007
0.005
0.004
0.003
0.003
0.004
2nd Max. 24-hr
DOWN
1
0.057
0.057
0.078
0.056
0.057
0.032
0.039
0.019
0.015
0.028
PEORIA-PEKIN, IL
CO
2nd Max. 8-hr
DOWN
1
7.9
7.7
7.4
6.3
7.2
7.3
5.7
5.6
4.6
4.7
LEAD
Max. Quarterly Mean
DOWN
1
0.04
0.04
0.04
0.02
0.02
0.03
0.02
0.03
0.02
0.02
OZONE
4th Max. 8-hr
NS
2
0.09
0.08
0.07
0.08
0.07
0.06
0.08
0.08
0.08
0.07
2nd Daily Max. 1-hr
NS
2
0.11
0.10
0.08
0.10
0.09
0.08
0.09
0.09
0.09
0.09
PM10
Weighted Annual Mean
NS
1
23
28
27
24
25
20
21
20
21
26
99th Percentile
NS
1
72
71
72
58
65
42
54
50
52
76
so2
Arithmetic Mean
NS
2
0.009
0.007
0.007
0.008
0.007
0.007
0.007
0.007
0.007
0.007
2nd Max. 24-hr
NS
2
0.062
0.046
0.055
0.065
0.043
0.039
0.049
0.084
0.045
0.042
PHILADELPHIA, PA-NJ
CO
2nd Max. 8-hr
DOWN
9
5.4
7.1
4.9
4.6
4.7
4.7
5.2
4.1
4.2
3.3
LEAD
Max. Quarterly Mean
UP
10
0.50
0.38
0.54
0.35
0.56
0.86
0.54
0.69
0.92
0.77
N02
Arithmetic Mean
DOWN
5
0.031
0.030
0.028
0.028
0.028
0.026
0.028
0.027
0.028
0.027
OZONE
4th Max. 8-hr
NS
8
0.13
0.10
0.10
0.11
0.09
0.10
0.09
0.11
0.09
0.10
2nd Daily Max. 1-hr
NS
8
0.17
0.13
0.13
0.14
0.11
0.13
0.12
0.13
0.12
0.13
PM10
Weighted Annual Mean
DOWN
6
36
35
32
35
29
30
33
30
30
30
99th Percentile
NS
6
83
85
75
87
84
81
81
78
71
99
so2
Arithmetic Mean
DOWN
11
0.012
0.011
0.010
0.010
0.008
0.008
0.009
0.007
0.007
0.007
2nd Max. 24-hr
DOWN
11
0.050
0.045
0.040
0.034
0.034
0.031
0.040
0.027
0.026
0.027
PHOENIX-MESA, AZ
CO
2nd Max. 8-hr
DOWN
8
8.0
7.8
6.7
6.2
6.5
6.0
6.3
6.2
5.7
5.1
LEAD
Max. Quarterly Mean
DOWN
2
0.16
0.09
0.09
0.11
0.06
0.05
0.05
0.06
0.04
0.03
OZONE
4th Max. 8-hr
UP
8
0.08
0.07
0.08
0.07
0.08
0.08
0.08
0.09
0.09
0.08
2nd Daily Max. 1-hr
NS
8
0.11
0.10
0.11
0.10
0.11
0.11
0.11
0.12
0.11
0.10
PM10
Weighted Annual Mean
DOWN
6
48
51
43
44
43
43
42
43
44
43
99th Percentile
NS
6
108
133
95
99
133
92
94
110
98
91
so2
Arithmetic Mean
NS
1
0.001
0.002
0.003
0.005
0.004
0.003
0.003
0.002
0.003
0.004
2nd Max. 24-hr
NS
1
0.001
0.006
0.011
0.013
0.010
0.009
0.009
0.008
0.017
0.010
PINE BLUFF, AR
PM10
Weighted Annual Mean
NS
1
27
27
21
19
22
23
25
26
23
25
99th Percentile
NS
1
77
77
55
46
66
57
63
73
52
78
PITTSBURGH, PA
CO
2nd Max. 8-hr
DOWN
5
5.1
5.3
5.6
4.3
4.8
3.8
4.3
3.8
3.3
2.5
LEAD
Max. Quarterly Mean
DOWN
4
0.13
0.12
0.09
0.09
0.07
0.07
0.08
0.06
0.04
0.05
N02
Arithmetic Mean
DOWN
5
0.023
0.023
0.023
0.023
0.022
0.022
0.023
0.021
0.021
0.020
OZONE
4th Max. 8-hr
NS
8
0.10
0.09
0.08
0.09
0.07
0.09
0.09
0.10
0.09
0.09
2nd Daily Max. 1-hr
NS
8
0.13
0.11
0.10
0.11
0.09
0.11
0.11
0.12
0.11
0.12
PM10
Weighted Annual Mean
DOWN
12
35
34
33
33
30
29
33
29
28
29
99th Percentile
DOWN
12
106
97
90
84
81
85
92
85
79
70
so2
Arithmetic Mean
DOWN
13
0.017
0.017
0.016
0.015
0.014
0.014
0.015
0.011
0.010
0.011
2nd Max. 24-hr
DOWN
13
0.075
0.072
0.070
0.055
0.068
0.060
0.071
0.045
0.042
0.045
PITTSFIELD, MA
OZONE
4th Max. 8-hr
NS
1
0.08
0.08
0.09
0.09
0.09
0.08
0.07
0.07
0.08
0.08
2nd Daily Max. 1-hr
NS
1
0.09
0.09
0.11
0.10
0.11
0.11
0.09
0.09
0.11
0.09
PONCE, PR
PM10
Weighted Annual Mean
DOWN
1
46
46
38
30
29
30
27
24
24
29
99th Percentile
NS
1
119
119
91
63
79
78
89
64
55
91
PORTLAND-VANCOUVER, OR-WA
CO
2nd Max. 8-hr
DOWN
2
8.9
8.2
8.5
9.1
7.0
6.3
7.0
5.7
6.1
5.4
LEAD
Max. Quarterly Mean
DOWN
2
0.12
0.07
0.06
0.06
0.05
0.06
0.04
0.03
0.02
0.04
OZONE
4th Max. 8-hr
NS
4
0.07
0.06
0.08
0.06
0.07
0.06
0.06
0.07
0.09
0.06
2nd Daily Max. 1-hr
NS
4
0.11
0.09
0.12
0.09
0.10
0.09
0.09
0.10
0.12
0.08
PM10
Weighted Annual Mean
DOWN
6
28
25
25
26
23
25
23
20
20
21
99th Percentile
DOWN
6
76
76
77
133
63
73
56
48
54
46
162 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan
Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
PORTLAND, ME
OZONE
4th Max. 8-hr
NS
1
0.12
0.10
0.09
0.11
0.10
0.09
0.09
0.10
0.08
0.10
2nd Daily Max. 1-hr
DOWN
1
0.17
0.13
0.13
0.14
0.12
0.11
0.12
0.12
0.10
0.13
PM10
Weighted Annual Mean
DOWN
1
24
26
23
25
23
21
21
21
20
23
99th Percentile
NS
1
64
57
49
54
60
64
59
69
42
60
so2
Arithmetic Mean
DOWN
1
0.010
0.010
0.010
0.009
0.008
0.009
0.008
0.006
0.005
0.005
2nd Max. 24-hr
DOWN
1
0.044
0.039
0.034
0.032
0.029
0.032
0.043
0.022
0.021
0.023
PORTSMOUTH-ROCHESTER, NH-ME
OZONE
4th Max. 8-hr
NS
2
0.11
0.09
0.08
0.10
0.09
0.09
0.09
0.09
0.08
0.10
2nd Daily Max. 1-hr
NS
2
0.17
0.12
0.11
0.14
0.11
0.11
0.11
0.12
0.10
0.13
PM10
Weighted Annual Mean
DOWN
2
21
21
20
19
19
18
14
15
16
17
99th Percentile
NS
2
57
66
46
56
90
56
48
51
45
48
so2
Arithmetic Mean
DOWN
1
0.006
0.008
0.007
0.007
0.006
0.006
0.006
0.004
0.004
0.004
2nd Max. 24-hr
DOWN
1
0.034
0.029
0.025
0.021
0.027
0.019
0.022
0.017
0.015
0.018
PROVIDENCE-FALL RIVER-WARWICK, RI-MA
CO
2nd Max. 8-hr
NS
1
7.3
6.2
7.3
7.4
6.3
5.4
6.7
7.0
4.4
5.6
N02
Arithmetic Mean
NS
1
0.024
0.024
0.024
0.025
0.023
0.022
0.022
0.022
0.025
0.025
OZONE
4th Max. 8-hr
NS
2
0.12
0.09
0.09
0.10
0.08
0.09
0.09
0.10
0.07
0.09
2nd Daily Max. 1-hr
DOWN
2
0.15
0.12
0.13
0.14
0.11
0.11
0.12
0.13
0.10
0.11
PM10
Weighted Annual Mean
DOWN
3
31
31
29
30
24
26
29
24
27
25
99th Percentile
NS
3
71
65
82
81
72
67
65
72
71
61
so2
Arithmetic Mean
DOWN
5
0.011
0.010
0.009
0.008
0.009
0.008
0.007
0.005
0.006
0.006
2nd Max. 24-hr
DOWN
5
0.050
0.043
0.039
0.039
0.044
0.036
0.035
0.022
0.030
0.030
PROVO-OREM,
UT
CO
2nd Max. 8-hr
DOWN
1
11.0
15.8
16.2
11.6
10.0
9.6
9.3
7.1
7.1
7.1
N02
Arithmetic Mean
NS
1
0.028
0.028
0.025
0.022
0.019
0.026
0.024
0.023
0.024
0.023
OZONE
4th Max. 8-hr
NS
1
0.08
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.08
0.07
2nd Daily Max. 1-hr
DOWN
1
0.11
0.11
0.09
0.08
0.09
0.08
0.08
0.08
0.10
0.08
PM10
Weighted Annual Mean
DOWN
3
50
49
32
42
37
38
34
29
34
30
99th Percentile
DOWN
3
212
194
104
196
169
161
96
86
116
92
PUEBLO, CO
PM10
Weighted Annual Mean
DOWN
1
35
33
26
30
26
26
30
26
26
27
99th Percentile
NS
1
71
84
75
63
61
52
63
100
59
88
RACINE, Wl
CO
2nd Max. 8-hr
DOWN
1
7.4
6.4
5.5
5.7
4.9
4.1
4.3
4.3
3.0
3.1
OZONE
4th Max. 8-hr
NS
1
0.14
0.11
0.09
0.10
0.08
0.08
0.09
0.10
0.08
0.10
2nd Daily Max. 1-hr
NS
1
0.18
0.14
0.11
0.14
0.10
0.10
0.11
0.11
0.13
0.12
RALEIGH-DURHAM-CHAPEL HILL, NC
CO
2nd Max. 8-hr
DOWN
1
10.9
10.9
8.7
8.8
7.3
7.2
6.9
6.6
5.6
6.6
OZONE
4th Max. 8-hr
NS
1
0.09
0.09
0.09
0.09
0.08
0.10
0.08
0.08
0.08
0.10
2nd Daily Max. 1-hr
NS
1
0.11
0.11
0.12
0.11
0.10
0.11
0.11
0.10
0.09
0.11
PM10
Weighted Annual Mean
DOWN
2
34
29
29
26
24
25
22
23
25
25
99th Percentile
NS
2
79
60
60
52
53
52
48
51
59
64
RAPID CITY, SD
PM10
Weighted Annual Mean
NS
2
29
26
27
28
25
23
29
24
23
25
99th Percentile
DOWN
2
96
83
100
111
62
87
74
78
69
58
READING, PA
CO
2nd Max. 8-hr
DOWN
1
5.2
5.0
6.4
4.6
4.6
3.8
5.4
3.9
3.4
3.0
LEAD
Max. Quarterly Mean
DOWN
11
0.58
0.68
0.61
0.66
0.57
0.48
0.50
0.34
0.33
0.38
N02
Arithmetic Mean
DOWN
1
0.024
0.023
0.022
0.022
0.020
0.021
0.023
0.021
0.022
0.021
OZONE
4th Max. 8-hr
NS
2
0.12
0.09
0.09
0.10
0.09
0.09
0.08
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
2
0.15
0.11
0.11
0.12
0.10
0.11
0.10
0.11
0.11
0.11
so2
Arithmetic Mean
DOWN
2
0.013
0.012
0.010
0.010
0.009
0.009
0.011
0.009
0.009
0.009
2nd Max. 24-hr
DOWN
2
0.053
0.048
0.038
0.034
0.033
0.033
0.040
0.033
0.036
0.030
REDDING, CA
OZONE
4th Max. 8-hr
NS
1
0.07
0.07
0.08
0.07
0.07
0.06
0.08
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
1
0.08
0.09
0.09
0.08
0.08
0.07
0.09
0.09
0.08
0.08
PM10
Weighted Annual Mean
DOWN
1
26
26
25
29
25
20
24
20
19
17
99th Percentile
DOWN
1
67
67
61
83
60
61
58
49
35
44
RENO, NV
CO
2nd Max. 8-hr
DOWN
5
7.1
7.3
7.0
7.5
5.9
5.0
6.0
4.4
5.2
5.0
OZONE
4th Max. 8-hr
NS
4
0.07
0.07
0.07
0.07
0.07
0.06
0.07
0.07
0.07
0.06
2nd Daily Max. 1-hr
DOWN
4
0.10
0.10
0.11
0.09
0.08
0.09
0.09
0.08
0.09
0.08
PM10
Weighted Annual Mean
DOWN
6
44
42
44
36
36
40
36
32
29
32
99th Percentile
DOWN
6
135
137
140
125
100
116
94
72
93
82
RICHMOND-PETERSBURG, VA
CO
2nd Max. 8-hr
DOWN
2
4.1
4.0
4.4
3.7
2.5
3.9
3.4
2.6
2.9
3.2
N02
Arithmetic Mean
DOWN
1
0.026
0.025
0.023
0.024
0.023
0.024
0.024
0.022
0.022
0.021
OZONE
4th Max. 8-hr
NS
4
0.12
0.08
0.08
0.09
0.09
0.10
0.09
0.09
0.08
0.10
2nd Daily Max. 1-hr
NS
4
0.14
0.11
0.11
0.11
0.12
0.12
0.11
0.11
0.10
0.12
PM10
Weighted Annual Mean
DOWN
3
28
28
25
26
22
23
21
23
24
22
99th Percentile
NS
3
68
71
72
61
49
64
39
58
67
68
APPENDIX A: DATA TABLES 163
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
Sites
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
S02 Arithmetic Mean
2nd Max. 24-hr
RIVERSIDE-SAN BERNARDINO, CA
CO
LEAD
N02
OZONE
PM10
SO,
2nd Max. 8-hr
Max. Quarterly Mean
Arithmetic Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
Weighted Annual Mean
99th Percentile
Arithmetic Mean
2nd Max. 24-hr
ROANOKE, VA
N02
OZONE
Arithmetic Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
ROCHESTER, MN
CO 2nd Max. 8-hr
PM10 Weighted Annual Mean
99th Percentile
ROCHESTER, NY
CO
LEAD
OZONE
PM10
SO,
2nd Max. 8-hr
Max. Quarterly Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
Weighted Annual Mean
99th Percentile
Arithmetic Mean
2nd Max. 24-hr
ROCKFORD, IL
CO
LEAD
OZONE
2nd Max. 8-hr
Max. Quarterly Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
SACRAMENTO, CA
CO 2nd Max. 8-hr
LEAD Max. Quarterly Mean
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
S02 Arithmetic Mean
2nd Max. 24-hr
SALINAS, CA
CO
N02
OZONE
2nd Max. 8-hr
Arithmetic Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
SALT LAKE CITY-OGDEN, UT
CO 2nd Max. 8-hr
LEAD Max. Quarterly Mean
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
SAN ANTONIO,TX
CO 2nd Max. 8-hr
LEAD Max. Quarterly Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
DOWN
NS
DOWN
NS
DOWN
DOWN
NS
NS
NS
NS
DOWN
DOWN
DOWN
NS
NS
DOWN
DOWN
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
NS
NS
DOWN
DOWN
1
1
7
4
7
16
16
10
10
4
4
1
1
1
2
2
1
1
1
1
1
2
1
2
2
2
2
2
2
1
1
2
2
1
1
6
2
5
6
6
0.009
0.042
4.7
0.08
0.030
0.16
0.22
66
173
0.002
0.012
0.016
0.10
0.13
37
82
0.004
0.018
7.1
29
64
4.0
0.09
0.11
0.13
30
99
0.012
0.038
8.1
0.13
0.09
0.11
17
39
9.5
0.08
0.018
0.10
0.14
0.010
0.020
2.3
0.014
0.06
0.08
25
54
7.8
0.16
0.026
0.09
0.14
43
132
0.011
0.054
5.7
0.06
0.09
0.12
28
76
0.009 0.006 0.006
0.032 0.034 0.027
0.005 0.007
0.024 0.023
0.006 0.005 0.005 0.005
0.022 0.016 0.027 0.024
5.1
0.06
0.030
0.16
0.22
69
266
0.002
0.013
0.014
0.08
0.10
35
71
0.005
0.022
6.3
30
70
3.6
0.04
0.09
0.10
24
65
0.013
0.054
6.6
0.07
0.08
0.09
25
62
9.0
0.07
0.018
0.08
0.11
0.006
0.020
2.3
0.014
0.07
0.10
25
54
7.7
0.12
0.027
0.09
0.14
45
129
0.011
0.081
6.3
0.04
0.08
0.11
28
80
4.4
0.05
0.029
0.14
0.21
62
261
0.002
0.006
0.013
0.08
0.09
36
72
0.004
0.018
6.1
28
102
3.5
0.03
0.09
0.11
21
59
0.012
0.040
6.5
0.09
0.07
0.09
25
78
8.9
0.10
0.018
0.09
0.13
0.006
0.010
2.5
0.012
0.06
0.08
23
56
6.8
0.08
0.019
0.08
0.11
33
99
0.009
0.039
5.4
0.07
0.08
0.10
25
53
5.1
0.06
0.029
0.15
0.21
58
177
0.002
0.008
0.014
0.08
0.10
33
75
0.004
0.019
6.3
23
43
3.3
0.03
0.10
0.11
26
72
0.011
0.043
5.1
0.04
0.08
0.09
22
57
8.2
0.04
0.016
0.10
0.14
0.003
0.010
2.1
0.012
0.06
0.08
23
46
7.5
0.08
0.020
0.08
0.11
41
152
0.010
0.051
4.6
0.03
0.08
0.11
25
81
3.6
0.03
0.027
0.14
0.19
50
170
0.002
0.009
0.013
0.07
0.09
32
68
0.004
0.016
5.1
21
44
3.5
0.04
0.08
0.09
22
60
0.011
0.039
4.6
0.06
0.08
0.09
21
49
6.2
0.02
0.016
0.09
0.12
0.002
0.010
2.3
0.012
0.06
0.07
23
66
6.5
0.05
0.022
0.07
0.10
36
131
0.009
0.046
4.7
0.03
0.07
0.10
25
68
3.5
0.04
0.028
0.13
0.18
49
127
0.002
0.006
0.014
0.08
0.10
35
79
0.004
0.018
4.9
20
45
3.2
0.04
0.08
0.09
23
76
0.010
0.041
4.3
0.03
0.07
0.08
16
47
6.4
0.05
0.017
0.09
0.12
0.001
0.003
2.1
0.012
0.07
0.08
22
86
6.4
0.07
0.025
0.08
0.10
37
115
0.007
0.043
5.1
0.03
0.08
0.11
23
57
3.5
0.04
0.028
0.13
0.19
47
123
0.002
0.004
0.013
0.08
0.10
36
72
0.004
0.011
5.0
21
53
4.5
0.04
0.08
0.09
20
48
0.011
0.043
4.0
0.04
0.08
0.10
19
46
6.2
0.02
0.014
0.09
0.11
0.001
0.004
2.0
0.012
0.06
0.08
20
50
5.9
0.05
0.026
0.08
0.11
32
105
0.004
0.013
3.5
0.03
0.09
0.11
23
51
3.4
0.04
0.029
0.13
0.18
47
139
0.002
0.005
0.013
0.08
0.09
34
81
0.003
0.010
4.0
20
50
3.2
0.04
0.09
0.11
21
49
0.010
0.038
4.5
0.03
0.09
0.10
19
59
5.2
0.02
0.015
0.10
0.13
0.001
0.004
1.7
0.011
0.06
0.07
21
50
4.5
0.05
0.024
0.08
0.12
29
79
0.003
0.013
3.8
0.03
0.09
0.12
21
75
2.9
0.04
0.027
0.12
0.16
45
120
0.001
0.004
0.013
0.07
0.08
33
84
0.003
0.014
4.0
19
59
3.7
0.04
0.07
0.08
21
65
0.009
0.033
3.2
0.05
0.08
0.09
18
45
4.9
0.01
0.015
0.09
0.12
0.001
0.003
2.4
0.011
0.06
0.08
20
50
6.2
0.03
0.026
0.09
0.11
33
119
0.003
0.014
4.8
0.02
0.08
0.12
19
39
3.1
0.04
0.024
0.11
0.15
44
114
0.001
0.004
0.013
0.08
0.10
30
84
0.003
0.013
4.0
20
39
1.9
0.04
0.09
0.10
20
53
0.008
0.038
3.7
0.03
0.07
0.08
26
73
4.5
0.01
0.013
0.08
0.10
0.001
0.003
1.7
0.010
0.05
0.07
21
59
5.4
0.07
0.024
0.08
0.10
29
85
0.003
0.008
4.7
0.02
0.08
0.10
19
46
164 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
SAN DIEGO, CA
CO
2nd Max. 8-hr
DOWN
7
6.1
6.6
5.8
5.4
5.0
4.5
4.8
4.2
4.2
3.8
LEAD
Max. Quarterly Mean
DOWN
3
0.10
0.08
0.09
0.04
0.03
0.03
0.02
0.03
0.02
0.02
N02
Arithmetic Mean
DOWN
7
0.028
0.027
0.025
0.025
0.024
0.020
0.021
0.021
0.019
0.019
OZONE
4th Max. 8-hr
DOWN
8
0.11
0.11
0.11
0.10
0.09
0.09
0.08
0.08
0.08
0.08
2nd Daily Max. 1-hr
DOWN
8
0.17
0.16
0.16
0.15
0.14
0.13
0.11
0.12
0.10
0.11
PM10
Weighted Annual Mean
DOWN
3
36
39
34
37
32
30
31
32
28
27
99th Percentile
NS
3
71
83
85
76
56
68
70
88
64
61
so2
Arithmetic Mean
DOWN
2
0.005
0.005
0.004
0.003
0.004
0.003
0.003
0.003
0.004
0.003
2nd Max. 24-hr
NS
2
0.014
0.016
0.015
0.018
0.019
0.010
0.014
0.012
0.014
0.013
SAN FRANCISCO, CA
CO
2nd Max. 8-hr
DOWN
4
6.3
5.9
5.7
6.2
4.8
4.6
4.3
3.7
3.9
3.4
LEAD
Max. Quarterly Mean
DOWN
1
0.10
0.08
0.04
0.04
0.02
0.03
0.02
0.03
0.01
0.02
N02
Arithmetic Mean
DOWN
1
0.026
0.026
0.021
0.024
0.022
0.024
0.022
0.021
0.022
0.020
OZONE
4th Max. 8-hr
NS
3
0.06
0.06
0.04
0.05
0.05
0.05
0.05
0.06
0.06
0.05
2nd Daily Max. 1-hr
NS
3
0.09
0.08
0.06
0.06
0.06
0.08
0.07
0.09
0.08
0.07
PM10
Weighted Annual Mean
DOWN
1
33
33
28
32
29
27
25
21
21
24
99th Percentile
DOWN
1
90
90
137
90
80
76
76
48
48
70
so2
Arithmetic Mean
DOWN
1
0.002
0.003
0.002
0.002
0.003
0.002
0.001
0.002
0.002
0.002
2nd Max. 24-hr
DOWN
1
0.012
0.015
0.010
0.013
0.012
0.010
0.005
0.005
0.007
0.006
SAN JOSE, CA
CO
2nd Max. 8-hr
DOWN
2
10.4
11.9
10.8
10.2
7.3
6.4
7.4
5.6
5.7
5.4
LEAD
Max. Quarterly Mean
DOWN
2
0.12
0.12
0.08
0.04
0.03
0.02
0.02
0.02
0.01
0.01
OZONE
4th Max. 8-hr
NS
4
0.09
0.08
0.07
0.07
0.07
0.07
0.07
0.08
0.08
0.06
2nd Daily Max. 1-hr
NS
4
0.12
0.11
0.11
0.11
0.11
0.11
0.10
0.12
0.11
0.08
PM10
Weighted Annual Mean
DOWN
4
38
39
36
34
30
26
26
22
21
22
99th Percentile
DOWN
4
129
140
147
115
102
83
82
54
64
76
SAN JUAN-BAYAMON, PR
CO
2nd Max. 8-hr
DOWN
2
5.4
5.5
5.3
5.3
5.3
4.5
4.8
4.9
4.0
3.9
PM10
Weighted Annual Mean
DOWN
6
33
34
35
30
28
32
30
26
27
32
99th Percentile
NS
6
87
87
84
77
72
81
77
63
64
94
so2
Arithmetic Mean
NS
2
0.007
0.007
0.007
0.010
0.009
0.008
0.008
0.006
0.005
0.004
2nd Max. 24-hr
DOWN
2
0.055
0.051
0.056
0.062
0.068
0.038
0.048
0.039
0.021
0.017
SAN LUIS OBISPO-ATASCADERO-PASO ROBLES,C
CO
2nd Max. 8-hr
DOWN
1
4.0
4.7
3.9
3.3
3.0
3.1
3.1
2.4
2.3
2.3
N02
Arithmetic Mean
DOWN
2
0.012
0.013
0.012
0.012
0.011
0.011
0.011
0.010
0.010
0.010
OZONE
4th Max. 8-hr
DOWN
5
0.08
0.07
0.07
0.07
0.06
0.06
0.06
0.06
0.07
0.06
2nd Daily Max. 1-hr
DOWN
5
0.09
0.09
0.09
0.08
0.08
0.08
0.08
0.08
0.08
0.08
PM10
Weighted Annual Mean
DOWN
2
27
27
24
26
22
23
21
21
18
20
99th Percentile
NS
2
59
59
61
57
40
68
61
52
42
63
so2
Arithmetic Mean
NS
3
0.001
0.001
0.001
0.001
0.001
0.001
0.002
0.002
0.002
0.001
2nd Max. 24-hr
DOWN
3
0.006
0.006
0.005
0.006
0.005
0.003
0.005
0.004
0.004
0.004
SANTA BARBARA-SANTA MARIA-LOMPOC, CA
CO
2nd Max. 8-hr
DOWN
4
2.6
2.8
2.4
2.3
2.3
2.2
2.5
2.1
1.9
1.6
LEAD
Max. Quarterly Mean
DOWN
1
0.05
0.05
0.03
0.03
0.01
0.02
0.01
0.01
0.01
0.01
N02
Arithmetic Mean
DOWN
19
0.008
0.008
0.007
0.007
0.006
0.006
0.006
0.006
0.006
0.006
OZONE
4th Max. 8-hr
DOWN
20
0.08
0.08
0.08
0.07
0.08
0.08
0.07
0.07
0.08
0.07
2nd Daily Max. 1-hr
DOWN
20
0.11
0.15
0.10
0.10
0.10
0.10
0.09
0.10
0.10
0.09
PM10
Weighted Annual Mean
NS
14
26
25
23
22
22
24
23
23
22
23
99th Percentile
NS
14
63
65
57
53
52
59
68
56
52
49
so2
Arithmetic Mean
NS
12
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
2nd Max. 24-hr
NS
12
0.004
0.003
0.003
0.003
0.003
0.004
0.003
0.003
0.003
0.002
SANTA CRUZ-WATSONVILLE, CA
CO
2nd Max. 8-hr
NS
1
1.0
1.1
1.0
1.0
1.0
1.0
1.2
0.8
0.7
0.7
N02
Arithmetic Mean
DOWN
1
0.008
0.009
0.008
0.010
0.007
0.006
0.006
0.005
0.005
0.004
OZONE
4th Max. 8-hr
NS
2
0.06
0.06
0.06
0.06
0.06
0.06
0.05
0.05
0.06
0.06
2nd Daily Max. 1-hr
NS
2
0.08
0.08
0.08
0.09
0.07
0.08
0.07
0.07
0.08
0.07
PM10
Weighted Annual Mean
DOWN
1
30
31
24
24
23
22
22
19
19
19
99th Percentile
NS
1
65
51
49
49
55
61
45
36
55
55
so2
Arithmetic Mean
NS
1
0.001
0.001
0.001
0.001
0.001
0.001
0.002
0.001
0.002
0.001
2nd Max. 24-hr
NS
1
0.007
0.004
0.003
0.002
0.006
0.006
0.006
0.008
0.003
0.002
SANTA FE, NM
CO
2nd Max. 8-hr
DOWN
1
3.8
3.5
3.5
3.9
3.7
3.4
2.7
2.3
2.2
2.1
PM10
Weighted Annual Mean
DOWN
2
17
16
17
14
16
15
14
13
14
14
99th Percentile
DOWN
2
58
45
48
32
37
35
30
33
32
31
SANTA ROSA, CA
CO
2nd Max. 8-hr
DOWN
1
4.9
5.0
4.3
3.8
3.5
3.8
3.2
2.4
3.0
3.1
N02
Arithmetic Mean
DOWN
1
0.016
0.015
0.015
0.015
0.016
0.016
0.015
0.015
0.014
0.013
OZONE
4th Max. 8-hr
NS
2
0.07
0.06
0.06
0.07
0.06
0.06
0.06
0.05
0.06
0.06
2nd Daily Max. 1-hr
NS
2
0.10
0.09
0.08
0.09
0.08
0.08
0.08
0.08
0.08
0.08
PM10
Weighted Annual Mean
DOWN
3
23
23
20
23
18
19
18
16
16
15
99th Percentile
DOWN
3
58
58
58
74
51
48
45
40
36
53
APPENDIX A: DATA TABLES 165
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
SARASOTA-BRADENTON, FL
CO
2nd Max. 8-hr
DOWN
1
6.3
6.3
6.2
6.9
5.6
6.5
5.3
5.9
5.1
5.3
OZONE
4th Max. 8-hr
NS
3
0.07
0.07
0.08
0.07
0.08
0.08
0.08
0.08
0.07
0.08
2nd Daily Max. 1-hr
DOWN
3
0.10
0.10
0.10
0.10
0.10
0.09
0.10
0.10
0.09
0.10
PM10
Weighted Annual Mean
NS
2
24
24
24
24
26
25
22
20
19
21
99th Percentile
NS
2
48
48
48
69
103
104
87
51
75
50
so2
Arithmetic Mean
NS
1
0.002
0.003
0.002
0.003
0.003
0.003
0.003
0.002
0.002
0.002
2nd Max. 24-hr
NS
1
0.012
0.017
0.016
0.035
0.021
0.018
0.017
0.010
0.018
0.009
SAVANNAH, GA
so2
Arithmetic Mean
NS
1
0.007
0.003
0.002
0.002
0.002
0.003
0.003
0.004
0.004
0.003
2nd Max. 24-hr
NS
1
0.046
0.013
0.008
0.009
0.008
0.011
0.015
0.013
0.019
0.013
SCRANTON—WILKES-BARRE—HAZLETON, PA
CO
2nd Max. 8-hr
DOWN
2
4.8
4.1
4.5
4.2
3.8
2.9
3.6
2.8
3.8
3.1
N02
Arithmetic Mean
DOWN
2
0.018
0.019
0.018
0.017
0.016
0.018
0.018
0.016
0.018
0.016
OZONE
4th Max. 8-hr
NS
3
0.11
0.08
0.09
0.10
0.08
0.09
0.08
0.09
0.08
0.09
2nd Daily Max. 1-hr
NS
3
0.13
0.10
0.10
0.12
0.10
0.11
0.10
0.10
0.10
0.10
PM10
Weighted Annual Mean
DOWN
3
29
29
25
29
25
26
28
25
24
26
99th Percentile
NS
3
75
75
65
73
49
73
64
69
57
79
so2
Arithmetic Mean
DOWN
2
0.010
0.009
0.010
0.009
0.008
0.007
0.007
0.005
0.006
0.007
2nd Max. 24-hr
DOWN
2
0.051
0.047
0.049
0.039
0.033
0.026
0.035
0.036
0.028
0.029
SEATTLE-BELLEVUE-EVERETT, WA
CO
2nd Max. 8-hr
DOWN
5
9.1
8.5
7.3
7.4
7.5
5.6
5.4
5.4
5.0
5.4
LEAD
Max. Quarterly Mean
NS
1
0.84
0.31
0.64
0.56
0.40
0.37
0.61
0.51
0.66
0.87
OZONE
4th Max. 8-hr
NS
2
0.08
0.08
0.09
0.07
0.08
0.07
0.06
0.07
0.08
0.07
2nd Daily Max. 1-hr
DOWN
2
0.12
0.11
0.13
0.10
0.10
0.10
0.12
0.09
0.11
0.08
PM10
Weighted Annual Mean
DOWN
7
31
32
29
30
29
28
23
22
20
22
99th Percentile
DOWN
7
93
96
87
94
75
79
59
65
61
76
so2
Arithmetic Mean
DOWN
2
0.007
0.007
0.008
0.008
0.008
0.008
0.006
0.005
0.004
0.004
2nd Max. 24-hr
DOWN
2
0.024
0.021
0.023
0.023
0.020
0.020
0.022
0.017
0.017
0.011
SHARON, PA
OZONE
4th Max. 8-hr
DOWN
2
0.12
0.09
0.09
0.10
0.09
0.09
0.09
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
2
0.14
0.10
0.10
0.11
0.10
0.11
0.11
0.11
0.10
0.10
PM10
Weighted Annual Mean
DOWN
1
37
35
30
36
27
28
30
28
29
28
99th Percentile
NS
1
84
88
85
76
61
66
82
74
101
60
so2
Arithmetic Mean
DOWN
1
0.011
0.011
0.010
0.009
0.008
0.008
0.008
0.008
0.007
0.007
2nd Max. 24-hr
DOWN
1
0.054
0.043
0.036
0.032
0.030
0.029
0.047
0.032
0.029
0.032
SHREVEPORT-BOSSIER CITY, LA
OZONE
4th Max. 8-hr
NS
2
0.09
0.08
0.09
0.08
0.08
0.09
0.08
0.08
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.11
0.12
0.11
0.10
0.10
0.11
0.09
0.10
0.10
0.10
PM10
Weighted Annual Mean
NS
1
23
23
23
28
24
22
24
24
22
23
99th Percentile
NS
1
47
47
47
130
106
68
51
56
46
99
so2
Arithmetic Mean
NS
1
0.003
0.004
0.002
0.002
0.004
0.004
0.002
0.001
0.002
0.002
2nd Max. 24-hr
NS
1
0.009
0.023
0.006
0.009
0.013
0.011
0.008
0.004
0.004
0.007
SIOUX CITY, IA-NE
PM10
Weighted Annual Mean
NS
1
31
28
28
28
25
23
23
26
33
28
99th Percentile
NS
1
98
83
74
70
93
58
71
73
107
102
SIOUX FALLS, SD
PM10
Weighted Annual Mean
NS
1
22
22
20
19
19
15
22
20
19
19
99th Percentile
NS
1
52
114
87
52
45
48
47
51
70
50
SOUTH BEND, IN
OZONE
4th Max. 8-hr
NS
2
0.10
0.07
0.08
0.08
0.08
0.08
0.08
0.09
0.09
0.09
2nd Daily Max. 1-hr
NS
2
0.12
0.08
0.09
0.10
0.10
0.09
0.10
0.11
0.11
0.11
PM10
Weighted Annual Mean
DOWN
2
29
30
31
30
23
24
27
22
20
17
99th Percentile
DOWN
2
79
72
90
68
70
65
95
55
55
45
SPOKANE, WA
CO
2nd Max. 8-hr
DOWN
3
9.9
9.4
9.1
9.3
8.1
8.0
6.4
6.9
6.8
5.1
OZONE
4th Max. 8-hr
UP
1
0.06
0.06
0.06
0.06
0.06
0.06
0.07
0.07
0.07
0.07
2nd Daily Max. 1-hr
NS
1
0.07
0.07
0.07
0.08
0.08
0.07
0.09
0.08
0.08
0.08
PM10
Weighted Annual Mean
DOWN
4
50
46
45
40
40
40
37
31
32
28
99th Percentile
DOWN
4
263
332
202
102
142
131
88
86
94
62
SPRINGFIELD,
IL
CO
2nd Max. 8-hr
DOWN
1
4.8
4.4
4.4
4.3
4.5
3.9
3.1
3.2
3.0
2.1
OZONE
4th Max. 8-hr
DOWN
1
0.10
0.08
0.08
0.08
0.08
0.08
0.08
0.08
0.08
0.07
2nd Daily Max. 1-hr
DOWN
1
0.11
0.11
0.10
0.10
0.09
0.11
0.10
0.10
0.10
0.09
so2
Arithmetic Mean
DOWN
1
0.007
0.007
0.007
0.008
0.006
0.006
0.006
0.006
0.006
0.006
2nd Max. 24-hr
NS
1
0.074
0.047
0.054
0.048
0.043
0.040
0.050
0.062
0.061
0.043
SPRINGFIELD,
MA
CO
2nd Max. 8-hr
NS
2
7.3
7.3
6.7
6.3
7.1
6.1
7.5
7.9
7.1
5.1
N02
Arithmetic Mean
DOWN
2
0.019
0.018
0.018
0.017
0.016
0.016
0.019
0.015
0.016
0.015
OZONE
4th Max. 8-hr
NS
4
0.13
0.09
0.09
0.10
0.09
0.10
0.09
0.09
0.08
0.09
2nd Daily Max. 1-hr
NS
4
0.16
0.12
0.12
0.13
0.12
0.13
0.12
0.12
0.10
0.12
166 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
PM,„
Weighted Annual Mean
DCWN
4
27
25
22
22
20
20
23
19
20
20
99th Percentile
NS
4
64
59
65
67
59
54
75
49
58
52
so2
Arithmetic Mean
DCWN
3
0.010
0.009
0.008
0.008
0.007
0.006
0.006
0.005
0.005
0.005
2nd Max. 24-hr
DCWN
3
0.049
0.040
0.033
0.031
0.034
0.023
0.048
0.023
0.024
0.021
SPRINGFIELD, MO
CO
2nd Max. 8-hr
DOWN
1
6.9
6.7
7.2
6.9
6.2
5.3
5.9
4.1
3.3
4.6
N02
Arithmetic Mean
UP
1
0.010
0.010
0.008
0.008
0.010
0.011
0.013
0.012
0.011
0.011
OZONE
4th Max. 8-hr
NS
2
0.08
0.07
0.06
0.06
0.06
0.07
0.07
0.08
0.07
0.07
2nd Daily Max. 1-hr
NS
2
0.09
0.07
0.08
0.07
0.08
0.08
0.09
0.10
0.09
0.08
PM10
Weighted Annual Mean
DOWN
3
22
22
22
18
19
17
17
17
18
16
99th Percentile
NS
3
55
50
52
35
53
40
55
45
61
51
so2
Arithmetic Mean
NS
2
0.006
0.006
0.006
0.003
0.004
0.006
0.008
0.003
0.005
0.002
2nd Max. 24-hr
NS
2
0.057
0.052
0.057
0.033
0.034
0.040
0.067
0.021
0.043
0.022
ST. JOSEPH,
MO
PM10
Weighted Annual Mean
DOWN
1
46
45
40
44
39
32
34
33
32
31
99th Percentile
NS
1
112
98
95
103
88
100
77
101
96
88
ST. LOUIS, MO-IL
CO
2nd Max. 8-hr
DOWN
7
4.6
4.8
4.0
4.1
3.3
3.3
3.5
3.3
3.3
3.2
LEAD
Max. Quarterly Mean
DOWN
12
1.99
0.81
0.71
0.62
0.64
0.50
0.56
0.57
0.61
0.46
N02
Arithmetic Mean
NS
8
0.020
0.019
0.018
0.018
0.019
0.018
0.019
0.019
0.018
0.018
OZONE
4th Max. 8-hr
NS
17
0.10
0.08
0.08
0.09
0.08
0.07
0.09
0.09
0.09
0.08
2nd Daily Max. 1-hr
NS
17
0.13
0.11
0.11
0.11
0.10
0.11
0.12
0.12
0.11
0.11
PM10
Weighted Annual Mean
DOWN
14
37
37
34
32
33
29
31
31
28
28
99th Percentile
DOWN
14
89
89
85
75
79
70
87
72
68
67
so2
Arithmetic Mean
DOWN
15
0.012
0.012
0.011
0.010
0.009
0.009
0.009
0.008
0.008
0.007
2nd Max. 24-hr
DOWN
15
0.054
0.056
0.042
0.042
0.039
0.041
0.041
0.037
0.039
0.034
STAMFORD-NORWALK, CT
CO
2nd Max. 8-hr
DOWN
1
6.9
6.0
6.3
6.0
5.5
5.2
6.2
5.4
4.1
5.1
OZONE
4th Max. 8-hr
DOWN
1
0.14
0.11
0.11
0.11
0.08
0.10
0.11
0.10
0.09
0.10
2nd Daily Max. 1-hr
DOWN
1
0.22
0.16
0.14
0.15
0.11
0.15
0.16
0.14
0.12
0.14
PM10
Weighted Annual Mean
NS
31
29
30
32
24
23
28
25
25
26
99th Percentile
NS
68
66
75
73
61
61
73
76
62
73
so2
Arithmetic Mean
DOWN
1
0.006
0.006
0.005
0.006
0.005
0.005
0.006
0.004
0.005
0.004
2nd Max. 24-hr
NS
1
0.031
0.029
0.024
0.025
0.022
0.020
0.028
0.023
0.019
0.025
STATE COLLEGE, PA
OZONE
4th Max. 8-hr
NS
1
0.12
0.08
0.10
0.10
0.09
0.10
0.09
0.10
0.08
0.08
2nd Daily Max. 1-hr
DOWN
1
0.14
0.10
0.11
0.12
0.10
0.12
0.10
0.11
0.09
0.09
STEUBENVILLE-WEIRTON, OH-WV
CO
2nd Max. 8-hr
DOWN
1
19.6
13.3
20.5
13.9
6.9
6.6
8.2
5.7
5.3
2.2
LEAD
Max. Quarterly Mean
NS
1
0.05
0.09
0.08
0.07
0.14
0.07
0.07
0.06
0.04
0.04
N02
Arithmetic Mean
DOWN
1
0.021
0.023
0.020
0.021
0.019
0.017
0.020
0.020
0.020
0.017
OZONE
4th Max. 8-hr
NS
2
0.10
0.08
0.07
0.09
0.08
0.08
0.08
0.09
0.08
0.08
2nd Daily Max. 1-hr
NS
2
0.12
0.10
0.09
0.11
0.09
0.10
0.10
0.11
0.10
0.09
PM10
Weighted Annual Mean
DOWN
6
41
42
37
40
36
34
35
34
32
27
99th Percentile
DOWN
6
110
126
94
108
100
97
98
97
98
67
so2
Arithmetic Mean
DOWN
6
0.026
0.026
0.025
0.024
0.019
0.019
0.018
0.011
0.011
0.011
2nd Max. 24-hr
DOWN
6
0.091
0.094
0.089
0.083
0.079
0.086
0.092
0.050
0.050
0.051
STOCKTON-LODI, CA
CO
2nd Max. 8-hr
DOWN
2
9.4
9.0
10.9
9.7
5.9
5.8
7.0
4.8
6.0
3.7
LEAD
Max. Quarterly Mean
DOWN
1
0.07
0.05
0.04
0.04
0.02
0.03
0.02
0.02
0.02
0.01
N02
Arithmetic Mean
DOWN
1
0.026
0.026
0.026
0.025
0.024
0.024
0.024
0.022
0.023
0.022
OZONE
4th Max. 8-hr
NS
2
0.10
0.08
0.09
0.09
0.09
0.08
0.09
0.09
0.08
0.07
2nd Daily Max. 1-hr
NS
2
0.12
0.11
0.12
0.11
0.11
0.11
0.12
0.13
0.10
0.09
PM10
Weighted Annual Mean
DOWN
2
42
46
45
49
39
36
35
31
26
29
99th Percentile
NS
2
109
124
181
133
110
101
105
108
113
95
SYRACUSE,
NY
CO
2nd Max. 8-hr
DOWN
1
7.8
9.7
6.8
8.4
7.5
5.6
6.5
3.3
3.9
4.0
PM10
Weighted Annual Mean
DOWN
3
32
32
27
29
27
24
24
23
23
23
99th Percentile
DOWN
3
77
77
69
82
64
75
69
55
61
55
TACOMA, WA
CO
2nd Max. 8-hr
NS
1
11.6
10.3
8.0
8.7
8.9
5.9
6.0
6.3
6.3
6.8
OZONE
4th Max. 8-hr
NS
1
0.08
0.07
0.09
0.08
0.08
0.07
0.07
0.07
0.08
0.07
2nd Daily Max. 1-hr
NS
1
0.11
0.09
0.13
0.09
0.10
0.10
0.11
0.09
0.10
0.08
PM10
Weighted Annual Mean
DOWN
3
34
36
31
32
34
29
24
24
22
24
99th Percentile
DOWN
3
119
109
84
89
97
80
74
66
60
78
so2
Arithmetic Mean
NS
2
0.007
0.007
0.008
0.008
0.009
0.009
0.007
0.006
0.006
0.006
2nd Max. 24-hr
DOWN
2
0.029
0.027
0.026
0.023
0.030
0.025
0.021
0.020
0.024
0.023
TAMPA-ST. PETERSBURG-CLEARWATER, FL
CO
2nd Max. 8-hr
DOWN
6
4.4
3.7
3.8
2.9
2.9
2.6
2.2
2.8
2.5
2.4
LEAD
Max. Quarterly Mean
DOWN
2
0.03
0.03
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
N02
Arithmetic Mean
DOWN
2
0.013
0.013
0.013
0.012
0.011
0.011
0.010
0.011
0.011
0.011
APPENDIX A: DATA TABLES 167
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan
Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
OZONE
4th Max. 8-hr
NS
6
0.08
0.08
0.08
0.07
0.07
0.07
0.08
0.07
0.07
0.08
2nd Daily Max. 1-hr
NS
6
0.11
0.10
0.11
0.10
0.10
0.09
0.10
0.10
0.10
0.10
PM10
Weighted Annual Mean
DCWN
3
29
29
28
29
26
27
26
25
25
25
99th Percentile
NS
3
61
60
52
54
62
105
93
56
79
65
so2
Arithmetic Mean
DCWN
7
0.006
0.007
0.006
0.005
0.005
0.005
0.005
0.004
0.004
0.005
2nd Max. 24-hr
DCWN
7
0.027
0.028
0.027
0.025
0.024
0.024
0.027
0.022
0.022
0.023
TERRE HAUTE,
IN
OZONE
4th Max. 8-hr
NS
1
0.07
0.09
0.09
0.09
0.07
0.07
0.09
0.09
0.10
0.08
2nd Daily Max. 1-hr
NS
1
0.08
0.11
0.11
0.10
0.08
0.09
0.11
0.10
0.11
0.10
PM10
Weighted Annual Mean
DOWN
5
34
33
33
30
26
25
25
27
22
23
99th Percentile
DOWN
5
108
92
98
77
66
67
67
67
51
57
so2
Arithmetic Mean
NS
2
0.008
0.009
0.011
0.011
0.007
0.009
0.010
0.007
0.009
0.006
2nd Max. 24-hr
NS
2
0.035
0.043
0.038
0.037
0.033
0.039
0.039
0.029
0.033
0.023
TEXARKANA, TX-TEXARKANA, AR
PM10
Weighted Annual Mean
NS
1
26
26
24
22
23
22
23
26
23
22
99th Percentile
NS
1
55
55
49
48
84
63
54
57
51
78
TOLEDO, OH
LEAD
Max. Quarterly Mean
NS
1
0.54
0.48
0.79
0.48
0.57
0.63
0.70
0.43
0.44
0.42
OZONE
4th Max. 8-hr
NS
2
0.11
0.08
0.08
0.09
0.08
0.08
0.09
0.09
0.09
0.08
2nd Daily Max. 1-hr
NS
2
0.13
0.10
0.10
0.11
0.09
0.11
0.11
0.11
0.11
0.10
PM10
Weighted Annual Mean
DOWN
1
36
36
26
29
28
25
26
25
22
22
99th Percentile
DOWN
1
64
64
66
76
62
74
60
58
43
43
so2
Arithmetic Mean
DOWN
2
0.009
0.007
0.006
0.006
0.006
0.007
0.007
0.004
0.004
0.004
2nd Max. 24-hr
NS
2
0.041
0.040
0.033
0.022
0.029
0.028
0.047
0.025
0.031
0.020
TOPEKA, KS
LEAD
Max. Quarterly Mean
DOWN
4
0.02
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
PM10
Weighted Annual Mean
NS
1
40
40
33
26
28
27
29
34
27
28
99th Percentile
NS
1
70
70
80
62
61
54
50
83
86
60
TRENTON, NJ
OZONE
4th Max. 8-hr
DOWN
2
0.12
0.10
0.11
0.12
0.11
0.10
0.10
0.11
0.09
0.10
2nd Daily Max. 1-hr
DOWN
2
0.17
0.14
0.14
0.15
0.14
0.13
0.14
0.13
0.12
0.12
PM10
Weighted Annual Mean
DOWN
1
32
30
29
31
26
27
29
24
27
27
99th Percentile
NS
1
87
69
77
68
56
72
65
58
79
87
TULSA, OK
CO
2nd Max. 8-hr
NS
2
4.2
5.6
4.7
4.6
5.1
3.9
3.9
3.4
5.3
5.7
LEAD
Max. Quarterly Mean
DOWN
1
0.13
0.20
0.11
0.21
0.10
0.20
0.10
0.09
0.11
0.02
N02
Arithmetic Mean
NS
2
0.013
0.014
0.011
0.013
0.013
0.013
0.013
0.010
0.012
0.012
OZONE
4th Max. 8-hr
NS
3
0.09
0.08
0.09
0.09
0.08
0.08
0.09
0.10
0.09
0.08
2nd Daily Max. 1-hr
NS
3
0.12
0.11
0.12
0.11
0.10
0.11
0.11
0.12
0.11
0.11
PM10
Weighted Annual Mean
NS
5
28
28
24
25
24
26
26
26
26
24
99th Percentile
NS
5
73
82
67
61
61
67
56
66
66
73
so2
Arithmetic Mean
NS
2
0.009
0.006
0.009
0.009
0.009
0.006
0.005
0.007
0.008
0.007
2nd Max. 24-hr
NS
2
0.045
0.035
0.046
0.052
0.048
0.035
0.031
0.031
0.036
0.029
TUSCALOOSA, AL
PM10
Weighted Annual Mean
DOWN
1
29
29
32
28
26
26
26
27
26
25
99th Percentile
NS
1
60
60
85
111
45
67
53
67
67
70
TUSCON, AZ
CO
2nd Max. 8-hr
DOWN
4
6.7
5.9
4.6
4.5
4.7
4.6
4.6
4.4
4.1
3.7
N02
Arithmetic Mean
DOWN
2
0.021
0.021
0.020
0.021
0.020
0.020
0.020
0.020
0.018
0.018
OZONE
4th Max. 8-hr
NS
7
0.07
0.07
0.07
0.07
0.07
0.07
0.07
0.08
0.07
0.07
2nd Daily Max. 1-hr
NS
7
0.09
0.09
0.09
0.08
0.09
0.09
0.09
0.09
0.09
0.09
PM10
Weighted Annual Mean
DOWN
9
38
40
33
26
24
22
22
26
25
26
99th Percentile
NS
9
92
100
99
62
58
53
46
71
61
69
so2
Arithmetic Mean
DOWN
1
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.001
0.002
2nd Max. 24-hr
DOWN
1
0.007
0.007
0.007
0.007
0.006
0.005
0.004
0.004
0.004
0.004
UTICA-ROME, NY
OZONE
4th Max. 8-hr
DOWN
1
0.10
0.08
0.09
0.09
0.08
0.07
0.07
0.08
0.06
0.07
2nd Daily Max. 1-hr
DOWN
1
0.12
0.09
0.10
0.10
0.09
0.09
0.09
0.10
0.08
0.09
VALLEJO-FAIRFIELD-NAPA, CA
CO
2nd Max. 8-hr
DOWN
2
7.3
7.4
6.9
6.6
5.6
5.6
5.2
4.2
4.2
4.4
OZONE
4th Max. 8-hr
NS
3
0.08
0.07
0.07
0.07
0.07
0.07
0.07
0.08
0.07
0.06
2nd Daily Max. 1-hr
NS
3
0.10
0.10
0.09
0.10
0.09
0.10
0.10
0.11
0.10
0.08
PM10
Weighted Annual Mean
DOWN
1
27
27
27
41
24
23
21
19
17
16
99th Percentile
DOWN
1
96
96
96
98
70
47
76
62
45
74
VENTURA, CA
CO
2nd Max. 8-hr
NS
2
3.3
3.0
3.3
3.1
2.3
2.5
2.8
3.2
2.4
2.4
LEAD
Max. Quarterly Mean
DOWN
1
0.04
0.04
0.02
0.03
0.01
0.01
0.01
0.01
0.01
0.01
N02
Arithmetic Mean
DOWN
4
0.016
0.017
0.016
0.015
0.014
0.014
0.014
0.014
0.013
0.012
OZONE
4th Max. 8-hr
DOWN
6
0.11
0.11
0.10
0.11
0.10
0.09
0.10
0.10
0.09
0.08
2nd Daily Max. 1-hr
DOWN
6
0.14
0.15
0.13
0.14
0.13
0.12
0.13
0.13
0.13
0.11
PM10
Weighted Annual Mean
DOWN
6
38
38
34
35
30
27
29
27
26
28
99th Percentile
NS
6
92
80
94
73
71
57
64
71
64
107
168 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (contined)
Metropolitan Statistical Area
Trend
#Trend
Sites
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
VINELAND-MILLVILLE-BRIDGETON, NJ
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
S02 Arithmetic Mean
2nd Max. 24-hr
VISALIA-TULARE-PORTERVILLE, CA
CO 2nd Max. 8-hr
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
WASHINGTON, DC-MD-VA-WV
CO 2nd Max. 8-hr
LEAD Max. Quarterly Mean
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
WATERBURY, CT
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
WEST PALM BEACH-BOCA RATON, FL
CO 2nd Max. 8-hr
N02 Arithmetic Mean
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
WHEELING, WV-OH
CO
OZONE
PM„
so2
2nd Max. 8-hr
4th Max. 8-hr
2nd Daily Max. 1-hr
Weighted Annual Mean
99th Percentile
Arithmetic Mean
2nd Max. 24-hr
WICHITA, KS
CO
LEAD
OZONE
2nd Max. 8-hr
Max. Quarterly Mean
4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
WILLIAMS PORT, PA
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
WILMINGTON-NEWARK, DE-MD
CO 2nd Max. 8-hr
OZONE 4th Max. 8-hr
2nd Daily Max. 1-hr
PM10 Weighted Annual Mean
99th Percentile
S02 Arithmetic Mean
2nd Max. 24-hr
WORCESTER, MA-CT
CO 2nd Max. 8-hr
N02 Arithmetic Mean
PM10 Weighted Annual Mean
99th Percentile
DOWN
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
NS
DOWN
DOWN
DOWN
NS
NS
NS
NS
NS
UP
NS
UP
NS
NS
NS
DOWN
DOWN
DOWN
NS
DOWN
DOWN
NS
NS
DOWN
NS
NS
NS
NS
NS
NS
NS
NS
DOWN
NS
NS
NS
DOWN
DOWN
DOWN
DOWN
DOWN
NS
5
7
12
12
0.13
0.15
0.009
0.034
5.6
0.023
0.10
0.12
60
125
6.4
0.04
0.025
0.12
0.16
29
80
0.009
0.030
31
90
0.010
0.055
4.0
0.013
0.06
0.10
19
39
0.001
0.004
4.0
0.10
0.12
34
88
0.021
0.072
7.0
0.03
0.08
0.10
31
71
0.10
0.12
29
72
0.009
0.035
5.3
0.13
0.19
32
61
0.016
0.054
5.6
0.029
27
65
0.11
0.13
0.008
0.049
5.9
0.021
0.10
0.13
61
196
6.2
0.05
0.025
0.09
0.11
31
84
0.010
0.038
32
71
0.11
0.13
0.007
0.024
5.0
0.021
0.10
0.12
69
225
5.2
0.05
0.027
0.09
0.12
26
73
0.008
0.030
34
86
3.7
0.013
0.06
0.10
19
39
0.003
0.009
5.2
0.08
0.11
34
81
0.021
0.065
7.9
0.03
0.07
0.07
30
72
0.07
0.08
29
72
0.007
0.042
4.5
0.10
0.12
42
87
0.016
0.048
7.9
0.11
0.12
0.007
0.023
5.3
0.022
0.10
0.12
61
149
5.0
0.03
0.026
0.10
0.13
26
61
0.008
0.029
30
69
0.010 0.010 0.009
0.048 0.042 0.038
2.7
0.014
0.07
0.09
19
39
0.002
0.007
7.1
0.08
0.11
30
85
0.020
0.064
5.9
0.02
0.08
0.10
28
69
0.07
0.09
26
64
0.006
0.025
5.4
0.10
0.14
37
107
0.013
0.043
6.0
3.1
0.012
0.06
0.08
18
41
0.002
0.012
5.6
0.09
0.11
31
68
0.020
0.074
5.9
0.02
0.08
0.09
31
86
0.08
0.10
31
74
0.007
0.025
4.0
0.11
0.14
33
67
0.012
0.033
7.2
0.09
0.10
0.006
0.021
4.3
0.020
0.10
0.12
51
110
4.4
0.02
0.026
0.09
0.11
22
45
0.008
0.033
23
63
0.10
0.12
0.006
0.019
3.5
0.023
0.11
0.13
49
100
5.0
0.02
0.026
0.10
0.12
22
63
0.008
0.027
24
65
0.007 0.006
0.029 0.021
0.026 0.022 0.023
26
58
23
60
21
50
3.7
0.011
0.05
0.07
20
63
0.003
0.010
5.6
0.08
0.10
30
75
0.018
0.077
5.6
0.01
0.07
0.08
32
84
0.07
0.09
24
45
0.007
0.029
4.1
0.09
0.12
28
72
0.013
0.046
8.0
0.024
20
44
3.1
0.013
0.08
0.12
19
70
0.004
0.028
4.1
0.08
0.11
29
80
0.018
0.075
5.0
0.01
0.06
0.08
31
91
0.08
0.09
24
63
0.006
0.025
3.8
0.09
0.14
29
71
0.013
0.041
6.1
0.028
20
46
0.09
0.10
0.005
0.032
4.0
0.023
0.11
0.13
42
101
4.5
0.02
0.026
0.09
0.12
21
51
0.008
0.031
26
57
0.007
0.030
2.8
0.012
0.07
0.08
18
63
0.003
0.016
4.6
0.08
0.10
28
75
0.015
0.065
4.9
0.01
0.07
0.09
26
71
0.07
0.08
28
64
0.006
0.042
4.3
0.09
0.12
38
85
0.012
0.044
0.09
0.13
0.004
0.016
4.2
0.023
0.10
0.12
47
121
4.4
0.02
0.023
0.10
0.12
22
51
0.007
0.020
24
73
0.005
0.019
2.8
0.012
0.06
0.08
18
45
0.002
0.019
5.0
0.09
0.10
28
67
0.010
0.055
5.2
0.01
0.07
0.10
27
92
0.07
0.09
28
60
0.006
0.027
4.6
0.12
0.14
37
77
0.010
0.036
0.09
0.11
0.005
0.016
3.9
0.018
0.10
0.13
40
96
3.9
0.01
0.023
0.08
0.11
20
51
0.007
0.028
26
68
0.005
0.022
2.5
0.012
0.06
0.09
18
63
0.002
0.014
3.5
0.09
0.11
28
82
0.011
0.058
5.8
0.01
0.07
0.09
25
100
0.07
0.08
25
64
0.006
0.028
3.6
0.08
0.11
32
71
0.009
0.035
0.10
0.12
0.004
0.018
3.5
0.019
0.10
0.12
40
94
4.0
0.01
0.023
0.09
0.12
20
54
0.007
0.022
24
47
0.005
0.020
3.6
0.012
0.06
0.08
20
65
0.002
0.013
3.1
0.08
0.11
24
49
0.010
0.043
4.8
0.01
0.08
0.09
22
66
0.08
0.09
26
57
0.008
0.028
4.5
0.09
0.12
32
92
0.008
0.034
5.9 4.2 5.3 3.4
0.025 0.021 0.019 0.019
20
46
19
53
20
54
20
52
APPENDIX A: DATA TABLES 169
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-14. Metropolitan Statistical Area Air Quality Trends, 1988-1997 (continued)
Metropolitan Statistical Area
Trend
#Trend
1988
1989
1990
1991
1992
1993
1994
1995
1996 1997
Sites
so2
Arithmetic Mean
DCWN
1
0.009
0.011
0.008
0.009
0.007
0.007
0.008
0.006
0.005
0.004
2nd Max. 24-hr
DCWN
1
0.042
0.040
0.034
0.029
0.033
0.025
0.024
0.023
0.021
0.021
YAKIMA,WA
CO
2nd Max. 8-hr
DOWN
1
8.9
8.7
7.4
9.0
8.8
7.9
8.0
7.1
7.4
7.4
PM10
Weighted Annual Mean
NS
1
34
34
34
44
32
38
31
24
35
35
99th Percentile
NS
1
112
112
112
255
89
97
89
55
119
110
YORK, PA
CO
2nd Max. 8-hr
DOWN
1
4.2
4.6
4.4
3.7
3.6
3.3
3.9
2.7
2.8
3.4
N02
Arithmetic Mean
DOWN
1
0.023
0.022
0.022
0.021
0.020
0.022
0.024
0.021
0.021
0.019
OZONE
4th Max. 8-hr
NS
1
0.12
0.09
0.10
0.10
0.08
0.09
0.08
0.09
0.08
0.09
2nd Daily Max. 1-hr
NS
1
0.14
0.10
0.12
0.11
0.10
0.11
0.12
0.10
0.10
0.11
PM10
Weighted Annual Mean
NS
1
33
31
30
32
27
31
32
30
28
31
99th Percentile
NS
1
88
79
91
76
51
95
82
68
63
82
so2
Arithmetic Mean
NS
1
0.007
0.008
0.007
0.008
0.007
0.008
0.009
0.006
0.007
0.009
2nd Max. 24-hr
NS
1
0.029
0.035
0.023
0.020
0.034
0.032
0.041
0.020
0.022
0.026
YOUNGSTOWN-WARREN, OH
OZONE
4th Max. 8-hr
NS
1
0.11
0.09
0.08
0.10
0.09
0.08
0.08
0.10
0.09
0.08
2nd Daily Max. 1-hr
DOWN
1
0.12
0.11
0.10
0.12
0.10
0.10
0.10
0.11
0.10
0.10
PM10
Weighted Annual Mean
DOWN
6
37
36
31
34
31
30
31
30
28
26
99th Percentile
DOWN
6
105
98
81
82
90
77
91
86
80
58
so2
Arithmetic Mean
DOWN
2
0.014
0.016
0.016
0.016
0.013
0.011
0.011
0.010
0.009
0.008
2nd Max. 24-hr
NS
2
0.077
0.043
0.053
0.048
0.056
0.063
0.051
0.038
0.044
0.037
YUBA CITY, CA
OZONE
4th Max. 8-hr
NS
2
0.09
0.08
0.08
0.08
0.09
0.08
0.08
0.09
0.09
0.07
2nd Daily Max. 1-hr
NS
2
0.11
0.09
0.10
0.10
0.11
0.11
0.10
0.11
0.11
0.09
PM10
Weighted Annual Mean
DOWN
1
39
39
39
39
34
30
34
33
29
29
99th Percentile
NS
1
96
96
96
108
79
78
154
128
82
98
CO = Highest second maximum non-overlapping 8-hour concentration (Applicable NAAQS is 9 ppm)
Pb = Highest quarterly maximum concentration (Applicable NAAQS is 1.5 ug/m3)
N02 = Highest arithmetic mean concentration (Applicable NAAQS is 0.053 ppm)
03 = Highest second daily maximum 1 -hour concentration (Applicable NAAQS is 0.12ppm)
= Highest fourth daily maximum 8-hour concentration (Applicable NAAQS is 0.08ppm)
PM10 = Highest weighted annual mean concentration (Applicable NAAQS is 50 ug/m3)
= Highest second maximum 24-hour concentration (Applicable NAAQS is 150 ug/m3)
= Highest 99th percentile 24-hour concentration (Applicable NAAQS is 150 ug/m3)
Data from exceptional events not included.
S02 = Highest annual mean concentration (Applicable NAAQS is 0.03ppm)
= Highest second maximum 24-hour concentration (Applicable NAAQS is 0.14 ppm)
170 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-15. Number of Days with PSI Values Greater Than 100 at Trend Sites, 1988-1997,
and All Sites in 1997
#of
Total
PSI
Metropolitan Statistical Area
Trend
#of
> 100
Sites
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
Sites
1997
AKRON, OH
5
46
15
9
30
8
10
8
12
11
6
7
6
ALBANY-SCHENECTADY-TROY, NY
7
23
4
4
9
5
5
6
3
4
3
13
3
ALBUQUERQUE, NM
21
9
9
8
5
0
0
1
1
0
0
26
0
ALLENTOWN-BETHLEHEM-EASTON, PA
7
35
11
10
14
3
6
10
17
6
13
9
13
ATLANTA, GA
9
44
17
52
24
19
42
13
43
22
26
17
36
AUSTIN-SAN MARCOS, TX
5
7
4
4
3
1
2
4
12
0
0
5
6
BAKERSFIELD, CA
7
126
114
97
109
100
97
97
104
109
55
18
58
BALTIMORE, MD
16
60
28
29
50
23
48
41
36
28
30
23
30
BATON ROUGE, LA
6
17
11
28
11
5
5
7
15
7
8
12
16
BERGEN-PASSAIC, NJ
8
27
12
9
11
2
3
5
10
3
5
9
5
BIRMINGHAM, AL
17
33
5
28
5
12
10
6
32
15
8
17
8
BOSTON, MA-NH
24
28
12
7
13
9
6
10
8
2
8
27
10
BUFFALO-NIAGARA FALLS, NY
21
31
4
8
9
3
1
4
6
3
1
21
1
CHARLESTON-NORTH CHARLESTON,SC
8
11
5
1
2
0
2
2
1
3
3
9
3
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC 10
43
13
31
12
11
23
9
13
18
26
31
31
CHICAGO, IL
42
40
16
5
21
4
3
8
21
6
9
64
10
CINCINNATI, OH-KY-IN
21
57
19
19
22
3
13
19
22
11
11
25
14
CLEVELAND-LORAIN-ELYRIA, OH
24
45
19
10
23
11
13
23
24
17
12
43
16
COLUMBUS, OH
9
24
7
4
9
1
6
7
7
11
5
14
14
DALLAS, TX
8
37
18
24
2
11
11
15
36
12
15
22
32
DAYTON-SPRINGFIELD, OH
10
37
10
13
12
2
11
14
11
18
9
13
13
DENVER, CO
20
35
16
11
7
8
3
2
2
0
0
32
0
DETROIT, Ml
30
35
18
11
28
8
5
13
14
13
12
35
12
EL PASO, TX
17
15
26
22
7
11
9
8
5
7
3
22
4
FORT LAUDERDALE, FL
7
3
6
1
0
2
4
1
1
1
0
19
0
FORT WORTH-ARLINGTON, TX
8
27
17
16
20
7
9
31
28
14
14
8
14
FRESNO, CA
9
110
91
62
83
61
59
55
60
65
50
16
75
GARY, IN
19
37
16
14
12
5
1
6
17
11
12
22
12
GRAND RAPIDS-MUSKEGON-HOLLAND, Ml
7
36
16
10
20
4
2
6
11
6
6
10
10
GREENSBORO-WINSTON-SALEM-HIGH PT, NC 8
46
8
12
5
2
21
9
8
6
13
22
17
GREENVILLE-SPARTANBURG-ANDERSON, SC 4
35
3
2
3
4
7
4
5
7
9
8
10
HARRISBURG-LEBANON-CARLISLE, PA
7
39
10
10
21
1
15
12
13
3
9
7
9
HARTFORD, CT
14
39
19
13
23
15
14
18
15
5
16
15
16
HONOLULU, HI
4
0
0
0
0
0
0
0
0
0
0
12
0
HOUSTON,TX
26
72
43
54
37
32
28
45
65
28
47
29
47
INDIANAPOLIS, IN
31
39
15
9
12
7
9
22
19
13
12
31
12
JACKSONVILLE, FL
15
4
4
3
0
2
3
2
1
1
4
17
4
JERSEY CITY, NJ
7
30
14
15
25
9
19
11
14
5
9
8
9
KANSAS CITY, MO-KS
22
23
5
2
11
1
3
10
22
10
18
25
18
KNOXVILLE, TN
13
33
2
23
10
7
20
13
20
19
36
21
38
LAS VEGAS, NV-AZ
6
30
45
22
10
6
9
14
4
5
0
19
6
LITTLE ROCK-NORTH LITTLE ROCK, AR
7
9
1
1
3
0
2
2
7
1
1
8
1
LOS ANGELES-LONG BEACH, CA
36
239
222
174
174
178
137
144
109
94
63
38
66
LOUISVILLE, KY-IN
17
49
15
10
15
2
19
27
21
10
13
26
18
MEMPHIS, TN-AR-MS
12
44
8
24
9
14
16
11
18
17
14
15
17
MIAMI, FL
10
8
6
1
1
3
6
1
2
1
3
12
3
MIDDLESEX-SOMERSET-HUNTERDON, NJ
4
35
19
22
24
8
11
9
15
8
18
4
19
MILWAUKEE-WAUKESHA, Wl
18
40
17
8
24
3
4
8
13
5
4
22
5
MINNEAPOLIS-ST. PAUL, MN-WI
24
11
8
4
2
3
0
2
7
2
0
41
0
APPENDIX A: DATA TABLES 171
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-15. Number of Days with PSI Values Greater Than 100 at Trend Sites, 1988-1997,
and All Sites in 1997 (continued)
Metropolitan Statistical Area
#of
Trend
Sites
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
Total
#of
Sites
PSI
> 100
1997
MONMOUTH-OCEAN, NJ
3
0
14
21
20
6
11
3
6
12
12
4
21
NASHVILLE, TN
19
55
11
31
13
6
18
21
27
23
20
19
24
NASSAU-SUFFOLK, NY
4
22
14
20
25
5
15
10
9
6
8
8
12
NEW HAVEN-MERIDEN, CT
10
26
11
15
30
10
12
13
14
8
19
10
19
NEW ORLEANS, LA
10
24
4
6
2
5
6
8
18
8
6
13
7
NEWYORK, NY
28
57
30
37
50
11
19
21
19
15
23
40
24
NEWARK, NJ
12
41
21
23
33
10
12
14
20
12
13
15
13
NORFOLK-VA BEACH-NEWPORT NEWS.VA-NC 11
23
4
8
6
7
12
4
3
4
15
12
17
OAKLAND, CA
19
8
6
4
4
3
4
3
12
11
0
33
0
OKLAHOMA CITY, OK
12
8
6
4
4
2
2
7
13
3
4
12
4
OMAHA, NE-IA
9
7
1
1
0
0
0
0
1
1
0
13
0
ORANGE COUNTY, CA
12
56
58
46
35
38
25
15
9
9
3
12
3
ORLANDO, FL
9
2
9
4
1
4
4
3
1
1
4
14
5
PHILADELPHIA, PA-NJ
34
53
44
39
48
24
50
26
30
22
32
49
39
PHOENIX-MESA, AZ
23
29
34
13
11
15
17
11
25
17
15
52
44
PITTSBURGH, PA
38
43
21
19
22
9
13
19
25
11
20
56
21
PONCE, PR
1
0
0
0
0
0
0
0
1
1
1
PORTLAND-VANCOUVER, OR-WA
12
9
5
12
10
6
0
3
2
6
0
17
0
PROVIDENCE-FALL RIVER-WARWICK, RI-MA 11
18
9
13
18
5
7
7
11
4
10
21
11
RALEIGH-DURHAM-CHAPEL HILL, NC
4
4
14
15
6
1
11
2
1
1
13
18
24
RICHMOND-PETERSBURG, VA
10
37
11
6
18
8
30
13
19
5
21
11
21
RIVERSIDE-SAN BERNARDINO, CA
36
185
190
158
159
175
167
148
125
118
106
56
123
ROCHESTER, NY
8
24
5
5
16
2
0
1
6
0
6
8
6
SACRAMENTO, CA
13
88
71
66
69
48
22
37
34
33
2
35
19
ST. LOUIS, MO-IL
53
44
29
24
33
16
9
32
35
20
15
60
15
SALT LAKE CITY-OGDEN, UT
12
16
22
5
20
9
2
4
4
9
1
26
2
SAN ANTONIO, TX
7
7
3
4
3
1
3
4
18
3
3
7
3
SAN DIEGO, CA
20
123
128
97
67
66
57
45
47
31
14
28
16
SAN FRANCISCO, CA
9
1
0
0
0
0
0
0
2
0
0
11
0
SAN JOSE, CA
8
24
21
10
13
3
4
2
9
7
0
11
0
SAN JUAN-BAYAMON, PR
10
0
0
0
0
0
0
0
0
1
2
27
2
SCRANTON-WILKES-BARRE-HAZLETON
PA 10
30
6
9
15
3
8
6
10
4
9
11
11
SEATTLE-BELLEVUE-EVERETT, WA
16
20
7
10
5
3
0
3
0
6
1
23
1
SPRINGFIELD, MA
13
29
10
13
15
12
13
12
10
5
10
13
10
SYRACUSE, NY
4
1
2
1
2
0
0
0
0
0
0
8
2
TACOMA, WA
7
10
4
5
1
3
0
2
0
1
0
9
0
TAMPA-ST. PETERSBURG-CLEARWATER, FL 22
9
4
6
1
1
1
3
2
3
4
32
4
TOLEDO, OH
5
29
8
3
6
1
4
9
7
10
3
8
5
TUSCON, AZ
21
6
2
1
0
1
1
1
3
0
1
27
1
TULSA, OK
12
23
5
16
12
2
4
12
21
14
7
13
7
VENTURA, CA
13
108
93
70
89
55
44
64
66
62
44
15
48
WASHINGTON, DC-MD-VA-WV
32
56
27
26
49
15
47
21
30
18
28
47
31
WEST PALM BEACH-BOCA RATON, FL
6
0
1
0
0
0
3
0
0
0
0
10
0
WILMINGTON-NEWARK, DE-MD
5
28
12
9
12
7
10
5
12
3
6
12
21
YOUNGSTOWN-WARREN, OH
9
25
8
3
14
5
2
0
11
5
3
14
10
172 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-16. (Ozone only) Number of Days with PSI Values Greater Than 100 at Trend Sites, 1988-1997,
and All Sites in 1997
#of
Metropolitan Statistical Area Trend
Sites
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
Total
#of
Sites
PSI
> 100
1997
AKRON, OH
2
46
15
9
30
8
10
8
12
11
6
2
6
ALBANY-SCHENECTADY-TROY, NY
3
23
4
4
9
5
5
6
3
4
3
3
3
ALBUQUERQUE, NM
7
1
0
2
0
0
0
1
0
0
0
9
0
ALLENTOWN-BETHLEHEM-EASTON, PA
3
34
11
10
14
3
6
9
17
6
13
3
13
ATLANTA, GA
4
44
17
52
24
19
42
13
43
22
26
7
36
AUSTIN-SAN MARCOS, TX
2
7
4
4
3
1
2
4
12
0
0
2
6
BAKERSFIELD, CA
5
123
111
95
107
100
97
97
104
109
55
8
58
BALTIMORE, MD
7
57
28
28
50
23
48
40
36
28
30
9
30
BATON ROUGE, LA
3
17
11
28
11
5
5
7
15
7
8
7
16
BERGEN-PASSAIC, NJ
1
26
10
8
11
2
3
5
10
3
5
1
5
BIRMINGHAM, AL
6
32
5
28
5
12
10
6
32
15
8
6
8
BOSTON, MA-NH
4
28
12
7
13
9
6
10
8
2
8
6
10
BUFFALO-NIAGARA FALLS, NY
2
31
4
7
9
3
1
4
6
3
1
2
1
CHARLESTON-NORTH CHARLESTON,SC
3
11
5
1
1
0
2
2
1
3
3
3
3
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC
3
43
12
29
12
11
23
9
13
18
26
7
31
CHICAGO, IL
16
40
15
3
21
4
3
7
21
6
9
22
10
CINCINNATI, OH-KY-IN
7
57
19
19
22
3
13
19
22
11
11
8
14
CLEVELAND-LORAIN-ELYRIA, OH
6
45
17
10
23
10
12
22
21
17
11
9
15
COLUMBUS, OH
2
24
7
4
9
0
6
7
7
11
5
5
14
DALLAS, TX
2
37
18
24
2
11
11
15
36
12
15
7
32
DAYTON-SPRINGFIELD, OH
3
37
10
13
12
2
11
14
11
18
9
5
13
DENVER, CO
5
20
5
4
0
1
0
0
0
0
0
9
0
DETROIT, Ml
8
34
18
11
28
7
5
11
12
12
12
8
12
EL PASO, TX
3
5
5
6
1
3
3
6
5
2
1
4
1
FORT LAUDERDALE, FL
3
3
6
1
0
2
4
1
1
1
0
3
0
FORT WORTH-ARLINGTON, TX
2
27
17
16
20
7
9
31
28
14
14
2
14
FRESNO, CA
4
109
89
54
81
61
59
55
60
65
50
7
75
GARY, IN
4
37
15
14
12
5
1
6
17
11
11
4
11
GRAND RAPIDS-MUSKEGON-HOLLAND, Ml
3
36
16
10
20
4
2
6
11
6
6
5
10
GREENSBORO-WINSTON-SALEM-HIGH PT, NC
3
41
4
12
5
2
21
9
8
6
13
6
17
GREENVILLE-SPARTANBURG-ANDERSON, SC
3
35
3
2
3
4
7
4
5
7
9
4
10
HARRISBURG-LEBANON-CARLISLE, PA
3
39
10
10
21
1
15
12
13
3
9
3
9
HARTFORD, CT
3
36
18
13
21
14
14
18
13
5
16
3
16
HONOLULU, HI
1
0
0
0
0
0
0
0
0
0
0
1
0
HOUSTON,TX
10
72
43
54
37
32
28
45
65
28
47
12
47
INDIANAPOLIS, IN
6
39
15
9
11
6
9
22
19
13
12
9
12
JACKSONVILLE, FL
2
4
4
3
0
2
3
2
1
1
4
3
4
JERSEY CITY, NJ
1
30
14
15
25
9
19
11
14
5
9
1
9
KANSAS CITY, MO-KS
6
23
4
2
11
1
3
10
22
9
18
7
18
KNOXVILLE, TN
4
33
2
23
10
7
20
13
20
19
36
7
37
LAS VEGAS, NV-AZ
3
2
2
2
0
1
2
2
0
2
0
4
0
LITTLE ROCK-NORTH LITTLE ROCK, AR
2
9
1
1
3
0
2
2
7
1
1
2
1
LOS ANGELES-LONG BEACH, CA
13
180
149
128
124
139
108
117
92
68
42
14
45
LOUISVILLE, KY-IN
4
49
13
10
15
2
19
27
21
10
13
7
18
MEMPHIS, TN-AR-MS
3
43
5
22
8
12
13
10
18
16
14
4
17
MIAMI, FL
4
8
5
1
1
3
6
1
2
1
3
4
3
MIDDLESEX-SOMERSET-HUNTERDON, NJ
1
35
19
22
24
8
11
9
15
8
18
2
19
MILWAUKEE-WAUKESHA, Wl
6
40
17
8
24
3
4
8
13
5
4
9
5
APPENDIX A: DATA TABLES 173
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-16. (Ozone only) Number of Days with PSI Values Greater Than 100 at Trend Sites, 1988-1997,
and All Sites in 1997 (continued)
#of
Metropolitan Statistical Area Trend
Sites
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
Total
#of
Sites
PSI
> 100
1997
MINNEAPOLIS-ST. PAUL, MN-WI
4
9
1
1
0
2
0
0
4
1
0
5
0
MONMOUTH-OCEAN, NJ
1
0
14
21
20
6
11
3
6
12
12
2
21
NASHVILLE, TN
7
55
9
31
13
6
18
21
27
23
20
7
24
NASSAU-SUFFOLK, NY
1
20
14
20
25
5
15
10
9
6
8
2
12
NEW HAVEN-MERIDEN, CT
2
26
11
13
28
10
12
13
14
8
19
2
19
NEW ORLEANS, LA
5
24
4
6
2
5
6
8
18
8
6
6
7
NEWYORK, NY
5
46
24
33
47
10
19
21
18
15
23
9
24
NEWARK, NJ
2
39
20
22
30
10
12
12
20
12
13
3
13
NORFOLK-VA BEACH-NEWPORT NEWS.VA-NC
2
22
4
8
6
7
12
4
3
4
15
3
17
OAKLAND, CA
7
8
6
4
3
3
4
3
12
11
0
10
0
OKLAHOMA CITY, OK
4
8
4
4
4
2
2
5
13
2
4
4
4
OMAHA, NE-IA
3
6
0
1
0
0
0
0
0
0
0
3
0
ORANGE COUNTY, CA
4
47
43
38
35
35
25
15
8
9
3
4
3
ORLANDO, FL
3
2
9
4
1
4
4
3
1
1
4
4
5
PHILADELPHIA, PA-NJ
8
53
42
39
48
24
50
25
30
22
32
10
32
PHOENIX-MESA, AZ
8
9
4
7
7
11
16
7
19
17
10
20
14
PITTSBURGH, PA
8
39
14
11
20
8
13
19
24
11
20
12
20
PONCE, PR
0
0
0
0
0
0
0
0
0
0
0
PORTLAND-VANCOUVER, OR-WA
4
3
0
8
3
6
0
1
2
6
0
4
0
PROVIDENCE-FALL RIVER-WARWICK, RI-MA
2
18
9
13
18
5
7
7
11
4
10
4
11
RALEIGH-DURHAM-CHAPEL HILL, NC
1
0
10
15
5
0
11
2
1
1
13
8
24
RICHMOND-PETERSBURG, VA
4
37
11
6
18
8
30
13
19
5
21
4
21
RIVERSIDE-SAN BERNARDINO, CA
16
183
182
153
157
173
167
148
120
115
102
21
117
ROCHESTER, NY
2
24
5
5
16
2
0
1
6
0
6
2
6
SACRAMENTO, CA
6
66
35
42
55
47
20
37
34
33
2
14
19
ST. LOUIS, MO-IL
17
44
25
24
33
16
9
32
35
20
14
17
14
SALT LAKE CITY-OGDEN, UT
2
13
14
5
3
0
2
4
4
6
1
7
2
SAN ANTONIO, TX
2
7
3
4
3
1
3
4
18
3
3
2
3
SAN DIEGO, CA
8
119
122
96
67
66
57
45
47
31
14
10
16
SAN FRANCISCO, CA
3
0
0
0
0
0
0
0
2
0
0
3
0
SAN JOSE, CA
4
19
7
4
5
3
4
2
9
7
0
6
0
SAN JUAN-BAYAMON, PR
0
0
0
0
0
0
0
0
0
0
0
1
0
SCRANTON-WILKES-BARRE-HAZLETON, PA
3
30
6
9
15
3
8
6
10
4
9
4
11
SEATTLE-BELLEVUE-EVERETT, WA
2
1
0
7
3
3
0
3
0
6
1
5
1
SPRINGFIELD, MA
4
29
10
13
15
12
13
12
9
4
10
4
10
SYRACUSE, NY
0
0
0
0
0
0
0
0
0
0
0
2
2
TACOMA, WA
1
2
0
4
0
2
0
2
0
1
0
2
0
TAMPA-ST. PETERSBURG-CLEARWATER, FL
6
8
4
6
1
1
1
3
2
3
4
7
4
TOLEDO, OH
2
29
8
3
6
1
4
9
7
10
3
5
5
TUSCON, AZ
7
0
0
1
0
1
1
1
3
0
1
7
1
TULSA, OK
3
23
5
16
12
1
4
12
21
14
7
3
7
VENTURA, CA
6
108
93
70
89
55
44
64
66
62
42
7
46
WASHINGTON, DC-MD-VA-WV
12
55
24
26
49
15
47
21
30
18
28
17
31
WEST PALM BEACH-BOCA RATON, FL
2
0
1
0
0
0
3
0
0
0
0
2
0
WILMINGTON-NEWARK, DE-MD
1
28
12
9
12
7
10
5
12
3
6
4
21
YOUNGSTOWN-WARREN, OH
1
25
8
3
14
5
2
0
11
5
3
3
10
174 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-17. Condensed Nonattainment Areas List(a)
State
Area Name(b)
Pollutant(c)
CO SO,
pmh
Pb NO,
Population(d)
CO SO, PM
10
Pb All
AK
AK
AK
AL
AZ
AZ
AZ
8 AZ
9 AZ
10 AZ
11 AZ
12 AZ
13 AZ
14 AZ
15 AZ
16 AZ
17 CA
18 CA
19 CA
20 CA
21 CA
22 CA
23 CA
24 CA
25 CA
26 CA
27 CA
28 CA
29 CO
30 CO
31 CO
32 CO
33 CO
34 CO
35 CO
36 CO
37 CO
38 CO
39 CT
40 DC-MD-VA
41 GA
42 GA
43 GU
44 GU
45 ID
46 ID
47 ID
48 ID
49 IL-IN
50
51
IN
KY
Anchorage
Fairbanks
Juneau
Birmingham
Ajo
Bullhead City
Douglas
Miami-Hayden
Morenci
Nogales
Paul Spur
Payson
Phoenix 1
Rillito
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
Muscogee Co. (Columbus)
Piti Power Plant
Tanguisson Power Plant
Boise
Bonner Co.(Sandpoint)
Pocatello
Shoshone Co.
Chicago-Gary-Lake County
Marion Co. (Indianapolis)
Boyd Co. (Ashland)
1(e)
1(f)
222
30
751
13
3
2,092 2,006
13,000 13,000
1,639
2,498
5,815
2,742
370
384
669
353
1,800
106
52
2,470
3,923
2,653
7,887
170
12
6
5
13
3
19
1
8
2,122
0
54
92
13,000
0
18
1,041
2,742
30
349
5
12
1,836
1
6
1
126
475
51
125
26
46
13
625
179
16
APPENDIX A: DATA TABLES 175
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-17. Condensed Nonattainment Areas List(a) (continued)
Pollutant(c)
Population(d)
State
Area Name(b)
°3
CO S02 PM10
Pb N02
°3
o
O
V)
O
PMi.
Pb
All
52
KY
Muhlenberg Co.
1
31
31
53
KY-IN
Louisville
1
834
834
54
LA
Baton Rouge
1
559
559
55
MA
Springfield (W. Mass)
1
812
812
56
MA-NH
Boston-Lawrence-Worcester
1
5,507
5,507
57
MD
Baltimore
1
2,348
2,348
58
MD
Kent and Queen Anne Cos.
1
52
52
59
ME
Portland
1
441
441
60
Ml
Muskegon
1
159
159
61
MN
Minneapolis-St. Paul
1
1
2,310
272
2,310
62
MN
Olmsted Co. (Rochester)
1
71
71
63
MO
Dent
1
2
2
64
MO
Liberty-Arcadia
1
2
2
65
MO-IL
St. Louis
1
1(g)
2,390
2
2,390
66
MT
Butte
1
33
33
67
MT
Columbia Falls
1
2
2
68
MT
Kalispell
1
11
11
69
MT
Lame Deer
1
0
0
70
MT
Lewis & Clark (E. Helena)
1
1(h)
2
2
2
71
MT
Libby
1
2
2
72
MT
Missoula
1
1
43
43
43
73
MT
Poison
1
3
3
74
MT
Ronan
1
1
1
75
MT
Thompson Falls
1
1
1
76
MT
Whitefish
1
3
3
77
MT
Yellowstone Co. (Laurel)
1
5
5
78
NE
Douglas Co. (Omaha)
1
1
1
79
NH
Portsmouth-Dover-Rochester
1
183
183
80
NM
Anthony
1
1
1
81
NM
Grant Co.
1
27
27
82
NM
Sunland Park
1(0
8
8
83
NV
Central Steptoe Valley
1
2
2
84
NV
Las Vegas
1
1
258
741
741
85
NV
Reno
1
1
134
254
254
86
NY-NJ-CT
NewYork-N. New Jersey-Long Island
1
1
1
17,943
13,155
1,487
17,943
87
OH
Cleveland-Akron-Lorain
3
1
. 1,898
1,412
1,898
88
OH
Coshocton Co.
1
35
35
89
OH
Gallia Co.
1
30
30
90
OH
Jefferson Co. (Steubenville)
1
1
80
4
80
91
OH
Lucas Co. (Toledo)
1
462
462
92
OH-KY
Cincinnati-Hamilton
1
1,705
1,705
93
OR
Grants Pass
1
1
17
17
17
94
OR
Klamath Falls
1
1
18
17
18
95
OR
LaGrande
1
11
11
96
OR
Lakeview
1
2
2
97
OR
Medford
1
1
62
63
63
98
OR
Oakridge
1
3
3
99
OR
Springfield-Eugene
1
157
157
100
PA
Lancaster
1
423
423
101
PA
Pittsburgh-Beaver Valley
1
2
1
2,468
446
75
2,468
102
PA
Warren Co
2
22
22
176 APPENDIX A: DATA TABLES
-------
NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-17. Condensed Nonattainment Areas List(a)
Pollutant(c)
Population(d)
State
Area Name(b)
°3
CO S02 PM10
Pb N02
°3
o
O
V)
O
PMi„
Pb
All
103
PA-DE-NJ-MD
Philadelphia-Wilmington-Trenton
1
6,010
6,010
104
PA-NJ
Allentown-Bethlehem
1
91
105
PR
Guaynabo Co.
1
85
85
106
Rl
Providence (all of Rl)
1
1,003
1,003
107
TN
Shelby Co. (Memphis)
1®
826
826
108
TN
Nashville
l(k)
81
81
109
TX
Beaumont-Port Arthur
1
361
361
110
TX
Dallas-Fort Worth
1
1(1)
3,561
264
3,561
111
TX
El Paso
1
1
1
592
54
515
592
112
TX
Houston-Galveston-Brazoria
1
3,731
3,731
113
UT
Ogden
1
1
63
63
63
114
UT
Salt Lake City
1
1
725
725
725
115
UT
Tooele Co.
1
26
26
116
UT
Utah Co. (Provo)
1
1
85
263
263
117
WA
Olympia-Tumwater-Lacey
1
63
63
118
WA
Seattle-Tacoma
3
730
730
119
WA
Spokane
1
1
279
177
279
120
WA
Wallula
1
47
47
121
WA
Yakima
1
54
54
122
Wl
Door Co.
1
26
26
123
Wl
Manitowoc Co.
1
80
80
124
Wl
Marathon Co. (Wausau)
1
115
115
125
Wl
M ilwau kee-Racine
1
1,735
1,735
126
Wl
Oneida Co. (Rhinelander)
1
31
31
127
WV
Follansbee
1
3
3
128
WV
New Manchester Gr. (in Hancock Co)
1
10
10
129
WV
Wier.-Butler-Clay (in Hancock Co)
1
1
25
22
25
130
WY
Sheridan
1
13
13
Total 38 20 34 77 10 0 99,824 34,047 4,695 29,890 1,375 113,001
Notes:
(a) This is a simplified listing of Classified Nonattainment areas. Unclassified and Section 185a nonattainment areas are not included. In certain cases,
footnotes 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 one 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 nonattain-
ment areas may only partially overlap, as in Figure A-2. These are counted as two distinct nonattainment areas and are listed on separate lines.
(c) 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 "AN" 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.
(f) Sulfur dioxide nonattainment area is a portion of Boyd county.
APPENDIX A: DATA TABLES 177
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Table A-17. Condensed Nonattainment Areas List(a) (continued)
(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.
Q) Lead nonattainment area is a portion of Shelby county, Tennessee.
(k) Lead nonattainment area is a portion of Williamson county, Tennessee.
0 Lead nonattainment area is Frisco, Texas, in Collin county.
NA for 03
NA for S02
Figure A-1. (Multiple NA areas within a larger NA area)
Two S02 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.
178 APPENDIX A: DATA TABLES
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APPENDIX II
Methodology
http://www.epa.gov/oar/aqtrnd97/appendb.pdf
Air Quality Data Base
The ambient air quality data pre-
sented in Chapter 2 of this report are
based on data retrieved from AIRS on
June 30,1998. 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 air quality
monitoring sites on a temporary basis
as a part of air pollution research stud-
ies. The national monitoring network
conforms to uniform criteria for moni-
tor siting, instrumentation, and quality
assurance.1,2
In 1997, 4,738 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 Monitoring Sta-
tions (SLAMS), or "other." NAMS were
established to ensure a long-term
national network for urban area-ori-
ented ambient monitoring and to
provide a systematic, consistent data
base for air quality comparisons and
trends analysis. SLAMS allow state or
local governments to develop net-
works tailored for their immediate
monitoring needs. "Other" monitors
may be Special Purpose Monitors,
industrial monitors, 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 1997
1988-1997
CO
538
368
Pb
381
195
no2
409
224
03
1,019
660
PM-io
1,733
845
S02
658
486
Total
4,738
2,778
Air quality monitoring sites are
selected as national trends sites if they
have complete data for at least eight
of the 10 years between 1988 and
1997. 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 complete-
ness criteria. Because of the annual
turnover of monitoring sites, the use
of a moving 10-year window maxi-
mizes the number of sites available 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 continuous (1-
hour) measurements. The daily mea-
surements 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 PMio
and lead. More frequent sampling of
PMio (every other day or every day) is
also common. Only PMio weighted
(for each quarter to account for sea-
sonality) annual arithmetic means that
meet the AIRS annual summary crite-
ria are selected as valid means for
trends purposes.3 Only lead sites with
at least six samples per quarter in
three of the four calendar quarters
qualify as trends sites. Monthly com-
posite lead data are used if at least two
monthly samples are available for at
least three of the four calendar quar-
ters.
Monitoring instruments that oper-
ate continuously produce a measure-
ment every hour for a possible total of
8,760 hourly measurements in a year.
For hourly data, only annual averages
based on at least 4,380 hourly obser-
vations are considered as trends sta-
tistics. The SO2 standard-related daily
statistics require at least 183 daily
values to be included in the analysis.
Ozone sites meet the annual trends
APPENDIX B: METHODOLOGY 179
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure B-1. Carbon monoxide monitoring network, 1997.
NAMS
°SLAMS
Other
Figure B-2. Lead monitoring network, 1997.
-ho_
• NAMS
°SLAMS
Other
180 APPENDIX B: METHODOLOGY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure B-3. Nitrogen dioxide, 1997.
++"
• NAMS
°SLAMS
Other
Figure B-4. Ozone monitoring network, 1997.
+ o
• NAMS
°SLAMS
Other
APPENDIX B: METHODOLOGY 181
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
Figure B-5. PM10 monitoring network, 1997.
\h-oj
+t
."H- o
oo Qj:
+ o
++ + f
•o
• NAMS
° SLAMS
o °
Other
Figure B-6. Sulfur dioxide monitoring network, 1997.
• NAMS
°SLAMS
Other
182 APPENDIX B: METHODOLOGY
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
data completeness 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.4
Air QualityTrend Statistics
The air quality statistics presented in
this report relate to the pollutant-
specific NAAQS and comply with the
recommendations of the Intra-Agency
Task Force on Air Quality Indicators.5
A composite average of each trend
statistic is used in the graphical pre-
sentations throughout this report. All
sites were weighted equally in calcu-
lating the composite average trend
statistic. Missing annual summary
statistics for the second through ninth
years for a site are estimated by linear
interpolation from the surrounding
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 conserva-
tive since endpoint rates of change are
dampened by the interpolated esti-
mates.
Emissions Estimates Methodology
Trends are presented for annual na-
tionwide emissions of CO, lead, \'Ox,
VOCs, PM10, and S02. These trends
are estimates of the amount and kinds
of pollution being emitted by automo-
biles, factories, and other sources
based upon best available engineering
calculations. Because of recent
changes in the methodology used to
obtain these emissions estimates, the
estimates have been recomputed for
each year. Thus, comparisons of the
estimates for a given year in this report
to the same year in previous reports
may not be appropriate.
The emissions estimates presented
in this report reflect several major
changes in methodologies that were
instituted mainly in 1997. First, state-
derived emissions estimates were
included primarily for nonutility point
and area sources. Also, 1985-1994
NOx emission rates derived from test
data from the Acid Rain Division, U.S.
EPA, were utilized. The MOBILE5b
model was run instead of MOBILE5a
for 1996 and 1997. The Office of
Mobile Sources, U.S. EPA, provided
new estimates from the beta version of
the non-road model for most non-
road diesel equipment categories.
Finally, additional improvements were
made to the particulate matter fugitive
dust categories.
In addition to the changes in meth-
odology affecting most source cat-
egories and pollutants, other changes
were made to the emissions for spe-
cific pollutants, source categories,
and/or individual sources. Activity
data and correction parameters for
agricultural crops, construction, and
paved roads were included. State-
supplied MOBILE model inputs 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 con-
tent of unleaded and leaded gasoline
for the on-road and non-road engine
lead emission estimates was revised,
and Alaska and Hawaii nonutility
point and area source emissions from
several sources were added. Also, this
report incorporates data from CEMs
collected between 1994 and 1997 for
NOx and SO2 emissions at major elec-
tric utilities.
All of these changes are part of a
broad effort to update and improve
emissions estimates. Additional emis-
sions estimates and a more detailed
description of the estimation method-
ology are available in two companion
reports, the National Air Pollutant
Emission Trends, 1900-1996 and the
National Air Pollutant Emission Trends
Procedures Document, 1900-1996.b>7
The Emission Trends report will not be
published this year. However, updated
emissions estimates can be found at
http:y7www.epa.gov/oar/emtrnd.
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 Stan-
dards, Research Triangle Park, NC,
October, 1993.
4. Ambient Air Quality Surveillance, 51
FR 9597, March 19, 1986.
5. U.S. Environmental Protection Agen-
cy Intra-Agency Task Force Report on
Air Quality Indicators, EPA-450/4-81-
015, U.S. Environmental Protection
Agency, Office of Air Quality Planning
and Standards, Research Triangle
Park, NC, February 1981.
6. National Air Pollutant Emission
Trends, 1900-1996, EPA-454/R-97-
011, U.S. Environmental Protection
Agency, Office of Air Quality Planning
and Standards, Research Triangle
Park, NC, December 1997.
7. National Air Pollutant Emission
Trends Procedures Document, 1900-
1996, EPA-454/R-98-008, U.S. Envi-
ronmental Protection Agency, Office
of Air Quality Planning and Stan-
dards, Research Triangle Park, NC,
June 1998.
APPENDIX B: METHODOLOGY 183
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT, 1997
184 APPENDIX B: METHODOLOGY
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