| Characteristic | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| One or more pollutants | 74.9 | 76.1 | 76.3 | 75.9 | 77.4 | 73.8 | 75.9 | 72.6 | 73.7 | 69.2 | 58.6 | 66.6 |
| Pollutant | ||||||||||||
| Carbon monoxide — 8-hour standard | 5.7 | 4.4 | 0.7 | 4.1 | 0.0 | 0.1 | 0.2 | 0.3 | 0.1 | 0.2 | 0.0 | 0.0 |
| Lead — 3-month standard | 2.3 | 1.6 | 2.2 | 1.2 | 1.6 | 1.2 | 1.6 | 1.2 | 5.0 | 5.0 | 4.2 | 6.4 |
| Nitrogen dioxide — 1-hour standard | 23.2 | 19.4 | 17.4 | 18.9 | 17.5 | 16.3 | 13.9 | 12.5 | 10.9 | 12.6 | 8.7 | 7.5 |
| Ozone — 8-hour standard | 65.2 | 64.9 | 66.3 | 66.1 | 67.8 | 61.6 | 66.2 | 65.3 | 64.1 | 59.2 | 48.9 | 59.0 |
| Particulate matter (PM2.5) — annual standard | 24.2 | 29.6 | 24.7 | 20.9 | 19.1 | 16.4 | 24.3 | 12.5 | 16.1 | 7.3 | 2.1 | 1.7 |
| Particulate matter (PM2.5) — 24-hour standard | 55.0 | 62.5 | 60.8 | 60.9 | 56.8 | 56.0 | 59.9 | 45.4 | 50.6 | 36.4 | 32.2 | 33.7 |
| Particulate matter (PM10) — 24-hour standard | 7.9 | 6.3 | 6.0 | 4.8 | 7.8 | 5.2 | 5.0 | 5.1 | 12.5 | 4.0 | 2.8 | 5.4 |
| Sulfur dioxide — 1-hour standard | 31.1 | 28.8 | 26.6 | 25.6 | 21.6 | 20.5 | 20.9 | 16.6 | 15.3 | 17.0 | 11.3 | 8.5 |
| NOTE: Percentages are based on the number of children living in counties where air pollution concentrations were higher than the level of a Primary National Ambient Air Quality Standard. The indicator is calculated with reference to the current levels of the air quality standards for all years shown. The Environmental Protection Agency (EPA) periodically reviews air quality standards and may change them based on updated scientific findings. Measuring concentrations above the level of a standard is not equivalent to violating the standard. The level of a standard may be exceeded on multiple days before the exceedance is considered a violation of the standard. Data have been revised since previous publication in America's Children. Values have been recalculated based on updated data in the Air Quality System. For more information on the air quality standards that are used in calculating these percentages, please see http://www.epa.gov/air/criteria.html. | ||||||||||||
| SOURCE: Environmental Protection Agency, Office of Air and Radiation, Air Quality System. | ||||||||||||
