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Air Trends

Our Nation's Air - Status and Trends through 2008 - Download Graphics

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The table below contains links to graphics (gif format) used in the Air Trends Report. The data used in the graphics are also available below in Excel format. Note that the data file is password protected. When the file opens and asks for a password, click on "Read Only" to view the data.

Figure Description
Figure 1 Number of people (in millions) living in counties with air quality concentrations above the level of the primary (health-based) National Ambient Air Quality Standards (NAAQS) in 2008.
Air Pollution
Figure 2 Distribution of national total emissions estimates by source category for specific pollutants, 2008.
Figure 3 Comparison of growth measures and emissions, 1990-2008.
Six Common Pollutants
Figure 4 Comparison of national levels of the six common pollutants to the most recent national ambient air quality standards, 1990-2008.  National levels are averages across all monitors with complete data for the time period.
Figure 5 Air quality trends in nonattainment areas above the NAAQS in 2008.
  EPA’s Air Quality Index
Figure 6 Number of days on which AQI values were greater than 100 during 2001-2008 in selected cities.
Figure 7 Ozone occurs both in the Earth’s upper atmosphere (stratosphere) and at ground level (troposphere). 
Figure 8 National 8-hour ozone air quality trends, 2001-2008 (average of annual fourth highest daily maximum 8-hour concentrations in ppm).
Figure 9 Change in ozone concentrations in ppm, 2001-2003 vs. 2006-2008 (three-year average of annual fourth highest daily maximum 8-hour concentrations).
Figure 10 Ozone concentrations in ppm, 2008 (fourth highest daily maximum 8-hour concentration).
Figure 11a
Figure 11b
Figure 11c
Figure 11d
Trends in annual summertime daily maximum 8-hour concentrations in ppm (May-September), before and after adjusting for weather nationally, in California, and in eastern states, and the location of rural and urban monitoring sites used in the averages.
Figure 12 Net radiative forcing (Watts per m2) associated with the three most important GHGs, based on concentrations in 2005 compared to pre-industrial levels.  (Source: National Academy of Sciences, 2005).
  Understanding the Contribution of Tropospheric Ozone to Climate Change
Particle Pollution
Figure 13a
Figure 13b
National PM2.5 air quality trends, 2001-2008 (annual average concentration and 98th percentile of 24-hour concentration in µg/m3).
Figure 14a
Figure 14b
Change in PM2.5 concentrations in µg/m3, 2001-2003 vs. 2006-2008 (3-year average of annual average and 98th percentile of 24-hour concentrations).
Figure 15a
Figure 15b
Annual average and 24-hour (98th percentile of 24-hour concentrations) PM2.5 concentrations in µg/m3, 2008.
Figure 16a
Figure 16b
Figure 16c
Figure 16d
Trends in annual, cool-month (October-April) and warm-month (May-September) average PM2.5 concentrations in µg/m3 (before and after adjusting for weather), and the location of urban monitoring sites used in the average.
Figure 17 Four-season average PM2.5 composition for 15 U.S. cities.
Figure 18a
Figure 18b
Figure 18c
Figure 18d
PM2.5 composition by season for 15 U.S. cities.
Figure 19 Net radiative forcing (Watts per m2) associated with the presence of different pollutants in the atmosphere, based on concentrations in 2005 compared to pre-industrial levels (Source: black carbon data [IPCC, 2007]. Carbon dioxide, organic carbon, sulfates data [National Academy of Sciences, 2005]).
  Understanding Linkages Between Black Carbon and Climate
Figure 20 National PM10 air quality trend, 2001-2008 (second maximum 24-hour concentrations in µg/m3).
Figure 21 Change in PM10 concentrations in µg/m3, 2001-2003 vs. 2006-2008 (3-year average of second maximum 24-hour concentrations).
Figure 22 PM10 concentrations in µg/m3, 2008 (second maximum 24-hour concentration).
Figure 23 National lead air quality trend, 2001-2008 (maximum 3-month average in µg/m3).
Figure 24 Lead concentrations in µg/m3, 2008 (maximum 3-month averages).
NO2, CO, and SO2
Figure 25 National NO2 air quality trend, 2001-2008 (annual average in ppm).
Figure 26 National CO air quality  trend, 2001-2008 (second maximum 8-hour average in ppm).
Figure 27 National SO2 air quality trend, 2001-2008 (annual average in ppm).
Toxic Air Pollutants
Figure 28 Estimated county-level cancer risk from the 2002 National-Scale Air Toxics Assessment (NATA2002).  Darker colors show greater cancer risk associated with toxic air pollutants.
Figure 29 Distribution of changes in ambient concentrations at U.S. toxic air pollutant monitoring sites, 2000-2005 (percent change in annual average concentrations). (Source: McCarthy M.C., Hafner, H.R., Chinkin L.R., and Charrier J.G. [2007] Temporal variability of selected air toxics in the United States. Atmos. Environ. 41[34], 7180-7194).
Atmospheric Deposition
Figure 30 Nitrogen (N) and sulfur cycling and interactions in the environment.
Figure 31a
Figure 31b
Figure 31c
Figure 31d
Three-year average deposition of sulfate (wet SO42-) and nitrate (wet NO3-) in 1989-1991 and 2006-2008 in kg/ha.  Dots show monitoring locations. (Data source: National Atmospheric Deposition Program, http://nadp.sws.uiuc.edu).
  Chesapeake Bay Airshed
  Sources of Nitrogen Loading to the Chesapeake Bay
Visibility in Scenic Areas
Figure 32 Trends in visibility on the 20 percent worst and best visibility days, 1998-2007. (Source: National Park Service/Air Resources Division, http://www.nature.nps.gov/air/).
Figure 33 Glide path to natural conditions in 2064 for Shenandoah (deciviews) compared to 2000-2004 baseline conditions (Source: Visibility Improvement State and Local Association of the Southeast – VISTAS).
Climate Change and Air Quality
Figure 34 Domestic greenhouse gas emissions in teragrams of carbon dioxide equivalents (TgCO2 eq), 1990-2007. (Source: http://www.epa.gov/climatechange/emissions/usinventoryreport.html).
Figure 35 Increases in average summertime ozone concentrations in the eastern U.S., due to climate change, are predicted for 2050. (Source: Figure 33 from EPA Assessment, 2009.  2050s-minus-present differences in simulated summer mean maximum daily average 8-hour ozone concentrations; reproduced from Figure 2 in Hogrefe, et al., 2004).
  Impacts of Short-Lived Pollutants on the Arctic Climate
International Transport of Air Pollution
Figure 36a
Figure 36b
Annual average surface ammonium sulfate concentrations in the Northern Hemisphere in 2001 from NASA’s GOCART (Goddard Chemistry Aerosol Radiation and Transport) model (top left panel) and the amount from major source regions in Asia (second panel), Europe (third panel), and North America (last panel).  Color scales are concentrations in µg/m3 and the contour lines show the percentage contributions to the total ammonium sulfate in 10, 30, 50, and 80 percent intervals. (Source: Chin et al., 2007, Atmospheric Chemistry and Physics, 7:5501-5517).
Figure 37 Marine shipping activity derived from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS).



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