The American Lung Association today released its 2007 "State of the Air" report, which includes good news and bad news about America's air quality.

The good news: Smog levels across much of the country are lower than they were from 2003 to 2005, especially in the eastern U.S.

The bad news: Soot levels are rising in the eastern half of the nation. Soot levels are also high in many parts of the western U.S., but soot levels have dropped there since 2003-2005.

The report also includes the American Lung Association's annual list of the metropolitan areas with the most and least year-round soot.

The top spots are unchanged from last year. Cheyenne, Wyo., still has the least sooty air, and Los Angeles continues to lead the country in sooty air.

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Cleanest Air

Following is the list of the top 26 metropolitan areas for clean air. Towns that tied received the same number.

1. Cheyenne, Wyo.

2. Santa Fe-Espanola, N.M.

3. Honolulu

4. Great Falls, Mont.

5. Farmington, N.M.

6. Flagstaff, Ariz.

6. Tucson, Ariz.

8. Anchorage, Alaska

8. Bismarck, N.D.

10. Albuquerque, N.M.

11. Salinas, Calif.

12. Pueblo, Colo.

13. Fort Collins-Loveland, Colo.

14. Rapid City, S.D.

14. Redding, Calif.

16. Duluth, Minn.-Wis.

16. Phoenix-Mesa-Scottsdale, Ariz.

16. Pocatello, Idaho

19. Fargo-Wahpeton, N.D.-Minn.

19. Midland-Odessa, Texas

21. Miami-Fort Lauderdale-Miami Beach, Fla.

22. Billings, Mont.

23. Colorado Springs, Colo.

23. San Luis Obispo-Paso Robles, Calif.

25. Reno-Sparks-Fernley, Nev.

25. Palm Bay-Melbourne-Titusville, Fla.

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Sootiest Air

Here is the list of the 26 U.S. cities with the most soot (particle pollution) in their air year-round. Metropolitan areas that tied received the same number.

1. Los Angeles-Long Beach-Riverside, Calif.

2. Pittsburgh-New Castle, Pa.

3. Bakersfield, Calif.

4. Birmingham-Hoover-Cullman, Ala.

4. Detroit-Warren-Flint, Mich.

6. Cleveland-Akron-Elyria, Ohio

7. Visalia-Porterville, Calif.

8. Cincinnati-Middletown-Wilmington, Ohio-Ken.-Ind.

9. Indianapolis-Anderson-Columbus, Ind.

10. St. Louis-St. Charles-Farmington, Mo.-Ill.

11. Chicago-Naperville-Michigan City, Ill.-Ind.-Wis.

11. Lancaster, Pa.

13. Atlanta-Sandy Springs-Gainesville, Ga.

14. York-Hanover-Gettysburg, Pa.

15. Fresno-Madera, Calif.

15. Weirton-Steubenville, W.Va.-Ohio

17. Hanford-Corcoran, Calif.

17. New York-Newark-Bridgeport, N.Y.-N.J.-Conn.-Pa.

19. Canton-Massillon, Ohio

20. Washington-Baltimore-Northern Virginia, D.C.-Md.-Va.-W.Va.

20. Charleston, W.Va.

22. Louisville-Jefferson County-Elizabethtown-Scottsburg, Ken.-Ind.

23. Huntington-Ashland, W.Va.-Ky.-Ohio

24. Philadelphia-Camden-Vineland, Pa.-N.J.-Del.-Md.

24. Hagerstown-Martinsburg, Md.-W.Va.

24. Rome, Ga.

This article was reviewed by Louise Chang, MD.

SOURCES: American Lung Association: "State of the Air: 2007." WebMD Medical News: "Top 25 Towns for Clean Air, Dirty Air."