LOS ANGELES (AP) - Metro Birmingham is listed as number 4 on the American Lung Association's most polluted U.S urban areas by year-round particle pollution. Hoover and Cullman also ranked fourth on the list.
Los Angeles tops the list, followed by Pittsburgh; Bakersfield, California; Birmingham; and Detroit.
The Lung Association based the rankings on 2003 - 2005 ozone pollution levels produced when heat and sunlight come into contact with pollutants from power plants, cars, refineries and other sources.
The group also studied particle pollution levels emitted from these sources, which are made up of a mix of tiny solid and liquid particles in the air.
Such pollution can contribute to heart disease, lung cancer and asthma attacks, the association said. Those especially vulnerable to polluted air are children, senior citizens, people who work or exercise outdoors and people with asthma or chronic obstructive pulmonary disease.
1: Los Angeles-Long Beach-Riverside, Calif.
2: Pittsburgh-New Castle, Pa.
3: Bakersfield, Calif.
4: Birmingham-Hoover-Cullman, Ala.
5: Detroit-Warren-Flint, Mich.
6: Cleveland-Akron-Elyria, Ohio
7: Visalia-Porterville, Calif.
8: Cincinnati-Middletown-Wilmington, Ohio, Ky., Ind.
9: Indianapolis-Anderson-Columbus, Ind.
10: St. Louis-St. Charles-Farmington, Mo., Ill.
11: Chicago-Naperville-Michigan City, Ill., Ind., Wis. (tie)
11: Lancaster, Pa.
13: Atlanta-Sandy Springs-Gainesville, Ga., Ala.
14: York-Hanover-Gettysburg, Pa.
15: Fresno-Madera, Calif. (tie)
15: Weirton-Steubenville, W.Va., Ohio
17: Hanford-Corcoran, Calif. (tie)
17: New York-Newark-Bridgeport, N.Y., N.J., Conn.
19: Canton-Massillon, Ohio
20: Washington-Baltimore-Northern Virginia, D.C., Md., Va. (tie)
20: Charleston, W.Va.
22: Louisville-Jefferson County-Elizabethtown-Scottsburg, Ky., Ind.
23: Huntington-Ashland, W.Va., Ky., Ohio
24: Philadelphia-Camden-Vineland, Pa., N.J., Del., Md. (tie)
24: Hagerstown-Martinsburg, Md., W.Va.
24: Rome, Ga.
(Copyright 2007 by The Associated Press. All Rights Reserved.)