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Air Trends

Latest Findings on National Air Quality -
Status and Trends through 2006 -
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Figure Description
Highlights
  Number of people living in counties with air quality concentrations above the level of the primary National Ambient Air Quality Standards (NAAQS) in 2006.
  Air Pollution Pathways
Six Principal Pollutants
Fig 1 Comparison of national levels of the six principal pollutants to national ambient air quality standards, 1980-2006.
  EPA’s Air Quality Index (AQI)
Fig 2 Number of days reaching Unhealthy for Sensitive Groups on the Air Quality Index for five of the six principal pollutants for 2001-2005 (average) vs. 2006.
Fig 3 Status of original nonattainment areas for one or more standards (i.e., ozone, annual PM2.5, PM10, NO2, CO, SO2, and lead) as of 2006.
Fig 4 Comparison of national annual emissions, 1980 vs. 2006.
Fig 5 Comparison of growth measures and emissions, 1980-2006.
  New National Monitoring Network. Location of candidate NCore sites.
Ground-Level Ozone
Fig 6 National 8-hour ozone air quality trend, 1990-2006 (average of annual fourth highest daily maximum 8 ‑ hour concentrations).
Fig 7 Change in ozone concentrations in ppm, 1990-1992 vs. 2004-2006 (3-year average of annual fourth highest daily maximum 8-hour concentrations).
Fig 8 Ozone concentrations in ppm, 2006 (fourth highest daily maximum 8-hour concentrations).
Fig 9 Number of days reaching Unhealthy for Sensitive Groups for ozone on the AQI for 2001-2005 (average) vs. 2006.
Fig 10a
Fig 10b
National trends in summertime ozone-forming emissions, 1997-2006.
Fig 11 Trends in average summertime daily maximum 8-hour ozone concentrations, before and after adjusting for weather, and the location of urban and rural monitoring sites used in the average.
Fig 12 Changes in summertime daily maximum 8-hour ozone concentrations (ppm) between 2000-2001 (average) and 2005-2006 (average).
  Where You Live. Local trends in ozone levels.
Particle Pollution
Fig 13 National PM2.5 air quality trend, 2000-2006 (annual average).
Fig 14 Change in PM2.5 concentrations in µg/m3, 2000 vs. 2006 (annual average).
Fig 15a
Fig 15b
Annual average and daily (98th percentile 24-hour concentrations) PM2.5 concentrations in µg/m3, 2006.
Fig 16 Number of days reaching Unhealthy for Sensitive Groups for PM2.5 on the AQI for 2001-2005 (average) vs. 2006.
Fig 17 National trends in annual direct PM2.5 and PM2.5 - forming emissions, 2000-2006.
Fig 18 Trends in annual average PM2.5 concentrations, before and after adjusting for weather, and the location of urban monitoring sites used in the average.
  Seasonal Influences on PM2.5. Change in warm (April-September) and cool season (October-March) PM2.5 concentrations in µg/m3 after removing the influence of weather, 2000-2001 (average) vs. 2005-2006 (average).
Fig 19 Regional trends in annual PM2.5 composition in µg/m3, 2002-2006.
Fig 20 National PM10 air quality trend, 1990-2006 (second maximum 24-hour concentration).
Fig 21 PM10 concentrations in µg/m3, 2006 (second maximum 24-hour concentration).
Fig 22 National trends in direct PM10 emissions, 1990-2006.
Nitrogen Dioxide
Fig 23 National NO2 air quality trend, 1990-2006 (annual average).
Fig 24 National trends in annual NOx emissions, 1990-2006.
Carbon Monoxide
Fig 25 National CO air quality trend, 1990-2006 (second maximum 8-hour average).
Fig 26 National trends in annual CO emissions, 1990-2006.
Sulfur Dioxide
Fig 27 National SO2 air quality trend, 1990-2006 (annual average).
Fig 28 National trends in annual SO2 emissions, 1990-2006.
Lead
Fig 29 National lead air quality trend, 1990-2006 (maximum quarterly average).
  New Information on Lead Sources
Toxic Air Pollutants
Fig 30 Air toxics monitoring sites operating in 2005 (by monitoring program).
Fig 31 Percent contribution by source sector to national air toxics emissions, 2002.
Fig 32 Trends in national air toxics emissions for 1990-1993 vs. 2002.
Fig 33 National benzene air quality trend, 2000-2005 (annual average).
Fig 34 Trends in annual average benzene concentrations at individual sites for any period of at least five years within 1990-2005.
Fig 35 Estimated county-level cancer risk from the 1999 National Air Toxics Assessment (NATA99).
Acid Rain
Fig 36a
Fig 36b
Three-year average precipitation of sulfate concentrations (SO4) in 1989-1991 and 2004-2006.
Visibility in Scenic Areas
  Visibility at Grand Canyon National Park
Fig 37a
Fig 37b
Trends in visibility (haze index in deciviews) on the 20 percent best and worst visibility days, 1996-2005.
Climate Change
Fig 38 Domestic greenhouse gas emissions in teragrams of carbon dioxide equivalents (Tg CO2 eq), 1990-2005.
Fig 39 Predicted increases in summertime daily maximum 8-hour ozone concentrations between the 1990s and 2050s.
  International Transport of Air Pollution

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