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Areas in Nonattainment of National Ambient Air Quality Standards for Criteria Pollutants


Reference numbers 1-124 do not indicate ranking.


KEY: CO = carbon monoxide; NO2 = nitrogen dioxide; O3 = ozone; Pb = lead; PM-10 = particulate matter smaller than 10 microns; SO2 = sulfur dioxide; . = all areas in attainment for a particle or pollutant.

a  This is a simplified listing of classified nonattainment areas. Unclassified and Section 185a (transitional) nonattainment areas are not included. Names of nonattainment areas are listed alphabetically within each state. Note that several smaller nonattainment areas may be inside one larger nonattainment area. In these cases, the smaller nonattainment areas are listed on the same line as the larger one, and the number of nonattainment areas are indicated under each pollutant.

b  Guam (U.S. territory)

c  National total includes Guam (U.S. territory).

d  The number of nonattainment areas for each of the criteria pollutants is listed. A dot (.) indicates that all areas are in attainment for that pollutant.

e  1-hour ozone standard.

f  Ozone nonattainment area is a portion of Dona Ana County, New Mexico.

g  Lead nonattainment area is Herculaneum, Missouri in Jefferson County.

h  Population figures were obtained from the 2000 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 "Total exposed" column is avoided by only counting the population of the larger nonattainment area.

The "Total exposed" values represent estimated population living in areas that are in nonattainment for at least one pollutant.


U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, National Air Quality and Emissions Trends Report, 2003 (Research Triangle Park, NC: 2003), table A-19.   Internet website as of Nov. 17, 2006.