U.S. Cities With the Dirtiest Air

American Lung Association Says Los Angeles Has Worst Ozone Levels

Medically Reviewed by Laura J. Martin, MD on April 28, 2010
From the WebMD Archives

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.

Twenty areas improved year-round levels of particle pollution over 2009.

These included Atlanta-Sandy Springs-Gainesville, Ga., Cincinnati-Middletown-Wilmington, Ohio, Detroit-Warren-Flint, Mich., Indianapolis-Anderson-Columbus, Ind., Louisville-Jefferson County-Elizabethtown-Scottsburg, Ky., Cleveland-Akron-Elyria, Ohio, Knoxville-Sevierville-La Follette, Tenn., Pittsburgh-New Castle, Pa., and St. Louis-St. Charles-Farmington, Mo.

The American Lung Association says all the cities reporting worse year-round particle levels were in California.

The clean-air efforts have especially helped cities in the East and Midwest, such as Atlanta, Cincinnati, Cleveland, New York, Pittsburgh, St. Louis, and the Washington, D.C.-Baltimore area.

Cleanest Cities

According to the American Lung Association, the 10 cleanest cities for long-term particle pollution were:

  1. Cheyenne, Wyo.
  2. Santa Fe-Espanola, N.M.
  3. Honolulu, Hawaii
  4. Anchorage, Alaska (tie)
  5. Great Falls, Mont. (tie)
  6. Tucson, Ariz.
  7. Amarillo, Texas
  8. Albuquerque, N.M.
  9. Flagstaff, Ariz.
  10. Bismarck, N.D.

The cleanest cities in terms of short-term particle pollution were:

  • Alexandria, La.
  • Amarillo, Texas
  • Athens-Clarke County, Ga.
  • Austin-Round Rock, Texas
  • Bangor, Maine
  • Billings, Mont.
  • Bloomington-Normal, Ill.
  • Brownsville-Harlingen-Raymondville, Texas
  • Cape Coral-Fort Myers, Fla.
  • Champaign-Urban, Ill.
  • Cheyenne, Wyo.
  • Claremont-Lebanon, N.H.-Vt.
  • Colorado Springs, Colo.
  • Corpus Christi-Kingsville, Texas
  • Fargo-Wahpeton, N.D.-Minn.
  • Farmington, N.M.
  • Fayetteville, N.C.
  • Fort Collins-Loveland, Colo.
  • Grand Junction, Colo.
  • Gulfport-Biloxi-Pascagoula, Miss.
  • Hattiesburg, Miss.
  • Jackson-Yazoo City, Miss.
  • Lafayette-Acadiana, La.
  • Lincoln, Neb.
  • Longview-Marshall, Texas
  • McAllen-Edinburg-Pharr, Texas
  • Oklahoma City-Shawnee, Okla.
  • Pueblo, Colo.
  • Salinas, Calif.
  • San Luis Obispo-Pasco Robles, Calif.
  • Santa Fe-Espanola, N.M.
  • Sarasota-Bradenton-Punta Gorda, Fla.
  • Springfield, Ill.
  • Springfield, Mo.
  • St. Joseph, Mo.-Kan.
  • Syracuse-Auburn, N.Y.
  • Topeka, Kan.
  • Tucson, Ariz.

Health Impact of Air Pollution

The American Lung Association says breathing tiny particles causes lung inflammation and can trigger and exacerbate diseases like asthma, chronic bronchitis, and chronic obstructive pulmonary disease.

The American Lung Association found that 14 of the 25 most ozone-polluted areas had fewer unhealthy days than in last year's report. Still, it said, 167.3 million Americans remain exposed to unhealthy levels of the nation's most widespread outdoor pollutant -- ozone, or smog.

Norman H. Edelman, MD, chief medical officer of the American Lung Association, says in a news release that inhaling ozone "irritates your lungs, leaving them with something like a bad sunburn."

Mary H. Partridge, board chair of the American Lung Association, says more needs to be done to clean the nation's air and calls for additional funding to install equipment to clean up 20 million dirty diesel vehicles still on the roads.

Show Sources


News release, American Lung Association.

American Lung Association: "2010 State of the Air report."

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