Air Scare: Ten Dirtiest Cities in America

Although air pollutions across the United States have declined up until three years ago, two in every five Americans, or 42 percent, still live in areas with unhealthy levels of either ozone or particle pollution, according to a new report by the American Lung Association. Meanwhile, one in three Americans live in counties where the monitored air quality places them at risk for decreased lung function, respiratory infection, lung inflammation, and aggravation of respiratory illness.

While the "State of the Air" report shows improvement among several of the worst-polluted cities, including Los Angeles (which is still the smoggiest city in the country), it tracks declines in many others, such as Pittsburg, Pa., which has the dubious honor of worst short-term particle pollution. Other cities with waning air quality include Atlanta; Charlotte; the Baltimore-Washington, D.C. metro area; Birmingham, Ala.; and San Diego.

Three types of air pollution are featured in the report: short term particles, year-round particles, and ozone. Ozone, a component of smog, formed when smokestack and tailpipe exhaust react with heat and sun, can scar lung tissue, as well as trigger asthma attacks and other respiratory illness. Small particles, which include dust and chemical droplets, on the other hand, can enter the lungs and bloodstream, resulting in what the Lung Association calls "a deadly cocktail of ash, soot, diesel exhaust, chemicals, metals, and aerosols."

Top 10 U.S. Cities Most Polluted by Short-Term Particle Pollution

1. Pittsburgh, Pa.
2. Los Angeles/Long Beach/Riverside, Calif.
3. Fresno/Madera, Calif.
4. Bakersfield, Calif.
5. Birmingham, Ala.
6. Logan, Utah
7. Salt Lake City, Utah
8. Sacramento, Calif.
9. Detroit, Mich.
10. Baltimore, Md./Washington, D.C./Northern Virginia.

Top 10 U.S. Cities Most Polluted by Year-Round Particle Pollution

1. Los Angeles/Long Beach/Riverside, Calif.
2. Pittsburgh, Pa.
3. Bakersfield, Calif.
4. Birmingham, Ala.
5. Visalia/Porterville, Calif.
6. Atlanta, Ga.
7. Cincinnati, Ohio
8. Fresno/Madera, Calif.
9. Hanford/Corcoran, Calif.
10. Detroit, Mich.

Top 10 U.S. Cities Most Polluted by Ozone

1. Los Angeles/Long Beach/Riverside, Calif. 2. Bakersfield, Calif.
3. Visalia/Porterville, Calif.
4. Houston, Texas
5. Fresno/Madera, Calif.
6. Sacramento, Calif.
7. Dallas-Fort Worth, Texas
8. New York, N.Y./Newark, N.J.
9. Baltimore, Md./Washington, D.C./Northern Virginia
10. Baton Rouge, La.

Visit State of the Air to find out how your neighborhood stacks up.

Difficulty level: Easy