5 Most Polluted U.S. Cities*

For the first time, a city outside California tops the list.

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  1. Pittsburgh-New Castle
  2. Los Angeles-Long Beach-Riverside
  3. Fresno-Madera, Calif.
  4. Bakersfield, Calif.
  5. Birmingham-Hoover-Cullman, Ala.

*By short-term particle pollution

Source: American Lung Association, "State of the Air 2008"