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Lung Disease & Respiratory Health Center

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U.S. Cities With the Dirtiest Air

American Lung Association Says Los Angeles Has Worst Ozone Levels
WebMD Health News
Reviewed by Laura J. Martin, MD

April 28, 2010 -- Major metropolitan areas in California still have some of the dirtiest air in the nation, despite a decade-long effort to reduce carbon emissions and other pollutants, finds a new report by the American Lung Association.

The Los Angeles-Long Beach-Riverside area has the worst ozone levels, measures third dirtiest in terms of year-round particle pollution, and fourth worst in short-term pollution, the ALA says in its 2010 State of the Air report.

The State of the Air report, using data collected from 2006 to 2008, says overall nearly six in 10 Americans live in areas with unhealthy levels of air pollution.

California had eight of the 10 cities with the worst ozone, five among the worst 10 in year-round particle pollution, and seven in short-term particle pollution.

City Rankings for Ozone Levels

Here is the list of the 10 metro areas with the worst ozone levels; the worst cities are at the top:

  1. Los Angeles-Long Beach-Riverside, Calif.
  2. Bakersfield, Calif.
  3. Visalia-Porterville, Calif.
  4. Fresno-Madero, Calif.
  5. Sacramento-Arden-Arcade-Yuba City, Calif.-Nevada
  6. Hanford-Corcoran, Calif.
  7. Houston-Baytown-Huntsville, Texas
  8. San Diego-Carlsbad-San Marcos, Calif.
  9. San Lois Obispo-Paso Robles, Calif.
  10. Charlotte-Gastonia-Salisbury, N.C.

City Rankings for Particle Pollution

The Phoenix-Mesa-Scottsdale area in Arizona ranked worst in year-round particle pollution, which comes from diesel and gasoline engines, power plants, demolition and construction projects, dust, and even soil.

After Phoenix-Mesa-Scottsdale, the cities with the worst year-round particle pollution include:

  1. Bakersfield, Calif.
  2. Los Angeles-Long Beach-Riverside, Calif. (tied)
  3. Visalia-Porterville, Calif. (tied)
  4. Pittsburgh-New Castle, Pa.
  5. Fresno-Madera, Calif.
  6. Birmingham-Hoover-Cullman, Ala.
  7. Hanford-Corcoran, Calif.
  8. Cincinnati-Middletown-Wilmington, Ohio (tied)
  9. St. Louis-St. Charles-Farmington, Mo.

The cities with the worst particle pollution over a 24-hour period were:

  1. Bakersfield, Calif.
  2. Fresno-Madera, Calif.
  3. Pittsburgh-New Castle, Pa.
  4. Los Angeles-Long Beach-Riverside, Calif.
  5. Birmingham-Hoover-Cullman, Ala.
  6. Sacramento-Arden-Arcade-Yuba City, Calif.
  7. Salt Lake City-Ogden-Clearfield, Utah.
  8. Visalia-Porterville, Calif.
  9. Modesto, Calif.
  10. Hanford-Corcoran, Calif.

Improving Trends

The American Lung Association says efforts to reduce emissions from coal-fired power plants and the transition to cleaner diesel fuels and engines have cut deadly ozone and particle pollution, even in Los Angeles.

Though the city had slightly worse average levels than in the American Lung Association's 2009 report, the Los Angeles metro area recorded its second lowest ozone levels since the association's first report in 2000.

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