Top 10 Most Polluted American Cities

In its annual State of the Air 2011 report, the American Lung Association has issued a ranking of the  metropolitan areas in the U.S. with the dirtiest air. There report assesses two primary pollution categories: ozone (smog) and particle pollution (soot).

Despite being one of the most  heavily regulated states, California in particular seems to get a failing grade in air quality, particularly in the ozone category.

Top 10 cites for ozone pollution:

1. Los Angeles-Long Beach-Riverside, Calif.
2. Bakersfield-Delano, Calif.
3. Visalia-Porterfield, Calif.
4. Fresno-Madera, Calif.
5. Sacramento, Calif., area
6. Hanford-Corcoran, Calif.
7. San Diego, Calif., area
8. Houston, Texas, area
9. Merced, CA
10. Charlotte, N.C., area

Top 10 cities for particle pollution:

1. Bakersfield-Delano, Calif.
2. Visalia-Porterfield, Calif.
3. Phoenix, Ariz., area
4. Los Angeles-Long Beach-Riverside, Calif.
5. Hanford-Corcoran, Calif.
6. Fresno-Madera, Calif.
7. Pittsburgh, Pa., area
8. Birmingham, Ala., area
9. Cincinnati, Ohio, area
10. Louisville, Ky., area

The report also contains a list of cities with the cleanest air. Honolulu gets the best grades for ozone while Cheyenne, Wyo., has the cleanest air in relation to particle pollution.

The rankings were derived from official U.S. Environmental Protection Agency data.

[Source: American Lung Association]