Jump to main content or area navigation.

Contact Us

Air Trends

1999 Air Trends Report - Download Graphics


Note: EPA no longer updates this information, but it may be useful as a reference or resource.

Please see www.epa.gov/airtrends for the latest information on Air Quality Trends.


Figure Description
2-1
Trend in 2nd maximum non-overlapping 8-hour average CO concentrations,1980 –1999
2-2
Trend in 2nd maximum non-overlapping 8-hour average CO concentrations by type of location,1980 –1999
2-3
Trend in CO 2nd maximum non-overlapping 8-hour concentrations by EPA region,1980 –1999
2-4
CO emissions by source category,1999
2-5
Density map of 1999 carbon monoxide emissions,by county
2-6
Trend in national total CO emissions,1980 –1999
2-7
Highest 2nd maximum non-overlapping 8-hour average CO concentration by county,1999
2-8
Trend in maximum quarterly average Pb concentrations (excluding point-source oriented sites),1980 –1999
2-9
Pb maximum quarterly mean concentration trends by location (excluding point-source oriented sites),1980 –1999
2-10
Trend in Pb maximum quarterly mean concentration by EPA region,1980 –1999
2-11
National total Pb emissions trend,1980 –1999
2-12
Pb emissions by source category,1999
2-13
Pb maximum quarterly concentration in the vicinity of Pb point sources,1999
2-14
Highest Pb maximum quarterly mean by county,1999
2-15
Trend in annual NO2 mean concentrations,1980 –1999
2-16
Trend in annual mean NO2 concentrations by type of location,1980 –1999
2-17
Trend in NO2 maximum quarterly mean concentration by EPA region,1980 –1999
2-18
Trend in national total NOx emissions,1980 –1999
2-19
NOx emissions by source category,1999
2-20
Density map of 1999 nitrogen dioxide emissions,by county
2-21
Highest NO2 annual mean concentration by county,1999
2-22
Trend in annual 2nd-highest daily maximum 1-hour,and 4th-highest daily 8-hour O3 concentrations,1980 –1999
2-23
Trend in 4th-highest daily 8-hour O3 concentrations,1980 –1999
2-24
Trend in 2nd highest daily 1-hour O3 concentration by EPA region,1980 –1999
2-25
Trend in 4th highest daily 8-hour O3 concentration by EPA region,1980 –1999
2-26
Trend in annual 2nd-highest daily maximum 1-hour O3 concentrations by location,1980 –1999
2-27
Comparison of actual and meteorologically adjusted 1-hour O3 trends,1980 –1999
2-28
Areas with PAMS networks
2-29
A comparison of the median change in summer morning concentrations of the most abundant VOC species measured
at all PAMS sites and PAMS type 2 sites from 1995 and 1999
2-30
Trend in 4th-highest daily 8-hour O3 based on 34 CASTNet sites in the rural eastern United States,1980 –1999
2-31
Trend in annual 4th-highest daily maximum 8-hour O3 concentrations in National Parks,1980 –1999
2-32
Trend in national total anthropogenic VOC emissions,1980 –1999
2-33
Anthropogenic VOC emissions by source category,1999
2-34
Density map of 1999 VOC emissions,by county
2-35
Highest second daily maximum 1-hour O3 concentration by county,1999
2-36
Highest fourth daily maximum 8-hour O3 concentration by county,1999
2-37
Trend in annual mean PM10 concentrations,1990 –1999
2-38
PM10 annual mean concentration trends by location,1990 –1999
2-39
National PM10 emissions trend,1980 –1999 (traditionally inventoried sources only)
2-40
PM10 emissions from traditionally inventoried source categories,1999
2-41
Total PM10 emissions by source category,1999.
2-42
PM10 emissions density by county,1999
2-43
Trend in PM10 annual mean concentration by EPA region,1990 –1999
Highest 2nd maximum 24-hour PM10 concentration by county,1999
Status of PM2.5 monitor network,as of May 2001
2-46
1999 annual mean PM2.5 concentrations (µg/m3)
2-47
1999 98th percentile 24-hour average PM2.5 concentrations (µg/m3)
2-48
Urban PM2.5 monthly patterns by region,1999
2-49
Rural PM2.5 monthly patterns by region,1999
2-50
Class I Areas in the IMPROVE Network meeting the data completeness criteria in Appendix B
2-51
Annual mean PM2.5 concentrations in 1999
2-52
PM2.5 concentrations,1992 –1999 at eastern IMPROVE sites meeting trends criteria
2-53
PM2.5 concentrations,1990 –1999 at western IMPROVE sites meeting trends criteria
2-54
PM2.5 concentrations,1990 –1999 at the Washington D.C.IMPROVE site
2-55
PM2.5 ambient composition
2-56
PM2.5 emission sources
2-57
Direct PM2.5 emissions density by county,1999
2-58
National direct PM2.5 emissions trend,1990 –1999 (traditionally inventoried sources only)
2-59
Direct PM2.5 emissions from traditionally inventoried source categories,1999
2-60
Total direct PM2.5 emissions by source category,1999
2-61
National ammonia emissions by principle source categories,1999
2-62
Estimated 1999 annual mean PM10 –2.5
2-63
Estimated 1999 98th percentile 24-hour average PM10 –2.5 developed from 1999 FRM monitor data
2-64
Trend in annual mean SO2 concentrations,1980 –1999
2-65
Annual mean SO2 concentration by trend location,1980 –1999
2-66
National total SO2 emissions trend,1980 –1999
2-67
SO2 emissions by source category,1999
2-68
Long-term ambient SO2 trend,1980 –1999
2-69
Trend in SO2 annual arithmetic mean concentration by EPA region,1980 –1999
2-70
Plants affected by the Acid Rain Program
2-71
Highest 2nd maximum 24-hour SO2 concentration by county,1999
3-1
Air Quality Index logo
3-2
Number of days with AQI values >100,as a percentage of 1990 value
3-3
Percent of days over 100 due to ozone
4-1
Location of nonattainment areas for criteria pollutants,September 2000
Classified ozone nonattainment areas
National contribution of source types to 1996 NTI emissions for the 188 HAPs
5-2
National contribution of source types to 1996 NTI emissions for the urban HAPs
5-3
National contribution by emission source type for individual urban HAPs and diesel particulate matter,1996
Urban/rural splits by source type for the 1996 national emissions of 188 HAPs
Urban/rural splits by source type for the 1996 national emissions of 33 urban HAPs
Change in national air toxics emissions – baseline ((1990 –1993)to 1996
Locations for urban and rural air toxics monitors with long-term data
National trend in annual average benzene concentrations in metropolitan areas,1994 –1999
National trend in annual average 1,3-butadiene concentrations in metropolitan areas,1994 –1999
National trend in annual average total suspended lead concentrations in metropolitan areas,1994 –1999
National trend in annual average perchloroethylene concentrations in metropolitan areas,1994 –1999
National trend in annual average styrene concentrations in metropolitan areas,1994 –1999
National trend in annual average toluene concentrations in metropolitan areas,1994 –1999
Trend in annual average benzene concentrations for metropolitan sites in California,1990 –1999
Trend in annual average 1,3-butadiene concentrations for metropolitan sites in California,1990 –1999.
Trend in annual average total suspended lead concentrations for metropolitan sites in California,1990 –1999
Trend in annual average perchloroethylene concentrations for metropolitan sites in California,1990 –1999
Trend in annual average styrene concentrations for metropolitan sites in California,1990 –1999
Trend in annual average toluene concentrations for metropolitan sites in California,1990 –1999
IMPROVE sites meeting data completeness requirements for sites operating in 1999
Comparison of the three visibility metrics (extinction,deciview and visual image)
Images of Shenandoah National Park and Yosemite National Park
Shenandoah National Park on clear and hazy days and the effect of adding 10 µg/m3 of fine particles to each
Long-term trends for 75th percentile light extinction coefficient from airport visual data (July –September)
Aerosol light extinction in 10 eastern Class I areas for the clearest 20 percent of the days in the distribution,1992 –1999
Aerosol light extinction in 10 eastern Class I areas for the middle 20 percent of the days in the distribution,1992 –1999
Aerosol light extinction in 10 eastern Class I areas for the haziest 20 percent of the days in the distribution,1992 –1999
Aerosol light extinction in 26 western Class I areas for the clearest 20 percent of the days in the distribution,1990 –1999
Aerosol light extinction in 26 western Class I areas for the middle 20 percent of the days in the distribution,1990 –1999
Aerosol light extinction in 26 western Class I areas for the haziest 20 percent of the days in the distribution,1990 –1999
Class I area significant trends in deciviews for the clearest 20 percent,middle 20 percent,and haziest 20 percent days
as summarized in Table 6-1
Class I area significant trends light extinction due to sulfate for the clearest 20 percent,middle 20 percent,and haziest 20 percent days as summarized in Table 6-1
Class I area significant trends for light extinction due to organic carbon for the clearest 20 percent,middle 20 percent,
and haziest 20 percent days as summarized in Table 6-1.
Aerosol light extinction in (Mm-1)for the clearest 20 percent days and contribution by individual particulate matter constituents,based on 1997 –1999 IMPROVE data
Aerosol light extinction in (Mm-1)for the middle 20 percent days and contribution by individual particulate matter constituents,based on 1997 –1999 IMPROVE data
Aerosol light extinction in (Mm -1) for the clearest 20 percent days and contribution by individual particulate matter constituents, based on 1997-1999 IMPROVE data.
Aerosol light extinction in (Mm -1) for the middle 20 percent days and contribution by individual particulate matter constituents, based on 1997-1999 IMPROVE data.
Aerosol light extinction in (Mm -1) for the haziest 20 percent days and contribution by individual particulate matter constituents, based on 1997-1999 IMPROVE data.
Current visibility impairment expressed in deciviews for the clearest 20 percent days based on 1997-1999 IMPROVE data.
Current visibility impairment expressed in deciviews for the middle 20 percent days based on 1997 –1999
IMPROVE data.
Current visibility impairment expressed in deciviews for the haziest 20 percent days based on 1997 –1999
IMPROVE data
The National Atmospheric Deposition Program/National Trends Network
Annual mean sulfate deposition from precipitation,1990 –1992 vs.1997 –1999
Annual mean ammonium deposition from precipitation,1990 –1992 vs.1997 –1999
Annual mean nitrate deposition from precipitation,1990 –1992 vs.1997 –1999
Rural annual mean SO2 concentrations from CASTNet,1990 –1992 vs.1997 –1999
Rural annual average sulfate concentrations from CASTNet,1990 –1992 vs.1997 –1999
CASTNet and subset of 34 long-term monitoring sites used for 1990 –1999 trends analysis
Trend in ambient sulfates in the rural eastern United States,based on CASTNet monitoring data,1990 –1999
Trend in ambient sulfur dioxide in the rural eastern United States,based on CASTNet monitoring data,1990 –1999
Rural annual mean ammonium concentrations from CASTNet,1990 –1992 vs.1997 –1999
Rural annual mean total nitrate concentrations from CASTNet,1990 –1992 vs.1997 –1999
Trend in annual mean ambient sulfur dioxide and sulfate concentrations,based on CASTNet monitoring data,and
regional SO2 emissions from electric utilities in rural eastern United States,1990 –1999
Trend in annual mean ambient sulfur dioxide and sulfate concentrations,based on CASTNet
monitoring data,and regional SO2 emissions from electric utilities in rural eastern United States by calendar quarter,
1990 –1999.
Trend in annual mean ambient sulfur dioxide and sulfate concentrations,based on CASTNet monitoring
data,and regional SO2 emissions from electric utilities in rural eastern United States by calendar quarter,1990 –1999.....125
Figure 7-14.Wet and dry components of sulfur deposition,1999
Wet and dry components of sulfur deposition,1999
Wet and dry components of nitrogen deposition,1999
Carbon monoxide monitoring network,1999
Lead monitoring network,1999
Nitrogen dioxide monitoring network,1999
Ozone monitoring network,1999
PM10 monitoring network,1999
Sulfur dioxide monitoring network,1999
Class I Areas in the Improve Network meeting data completeness criteria

Related Links | Acronyms | Hardcopies

Jump to main content.