Top 10 Most Polluted Air

  • Bakersfield–Delano, Calif.
  • Visalia–Porterville, Calif.
  • Phoenix–Mesa–Glendale, Ariz.
  • Los Angeles–Long Beach–Riverside, Calif.
  • Hanford–Corcoran, Calif.
  • Fresno–Madera, Calif.
  • Pittsburgh–New Castle, Pa.
  • Birmingham–Hoover–Cullman, Ala.
  • Cincinnati–Middletown–Wilmington, Ohio–Ky.–Ind.
  • Louisville-Jefferson County-Elizabethtown-Scottsburg, Ky.-Ind; Modesto, Calif.

Every year the American Lung Association (ALA) prepares a "State of the Air" report, using data from the U.S. Environmental Protection Agency. The agency measures the air quality of U.S. cities in terms of ozone, year-round particle pollution and short-term particle pollution. The listed cities had the most annual particle pollution in the air.

Top 10 Cleanest Air

  • Cheyenne, Wyo.
  • Santa Fe–Espanola, N.M.
  • Tucson, Ariz.
  • Honolulu
  • Great Falls, Mont.
  • Anchorage, Alaska
  • Amarillo, Texas
  • Albuquerque, N.M.
  • Redding, Calif.
  • Salinas, Calif.

As part of the "State of the Air" report, the ALA also lists the cities with the least ozone and particle pollution. These cities had the cleanest air quality in terms of year-round particle pollution.

Tomorrow: Part 4—The Top 10 Tech-Friendly Cities
Yesterday: Part 2—The Top 10 Healthiest Cities