Who's Got the Cleanest Air Year-Round?

1. Cheyenne, Wyo.
2. Santa Fe-Espanola, N.M.
3. Honolulu
4. Great Falls, Mont.
5. Tucson, Ariz.
6. Anchorage, Alaska
7. Farmington, N.M.
7. Bismark, N.D.
9. Albuquerque, N.M.
10. Rapid City, S.D.
11. Pueblo, Colo.
12. Fort Collins-Loveland, Colo.
12. Fargo-Wahpeton, N.D.-Minn.
12. Duluth, Minn.-Wis.
15. Salinas, Calif.
15. Midland-Odessa, Texas
17. Palm Bay-Melbourne-Titusville, Fla.
18. Colorado Springs, Colo.
18. Cape Coral-Fort Myers, Fla.
18. Albany-Corvallis-Lebanon, Ore.
21. Reno-Sparks, Nev.
22. Redding, Calif.
22. Port St. Lucie-Fort Pierce, Fla.
24. Santa Barbara-Santa Maria-Goleta, Calif.
25. San Luis Obispo-Paso Robles, Calif.

Who's Got the Sootiest Air Year-Round?

1. Los Angeles-Long Beach-Riverside, Calif.
2. Bakersfield, Calif.
3. Pittsburgh-New Castle, Pa.
4. Visalia-Porterville, Calif.
5. Fresno-Madera, Calif.
6. Detroit-Warren-Flint, Mich.
7. Hanford-Corcoran, Calif.
8. Cleveland-Akron-Elyria, Ohio
9. Birmingham-Hoover-Cullman, Ala.
9. Atlanta-Sandy Springs-Gainesville, Ga.-Ala.
11. Chicago-Naperville-Michigan City, Ill.-Ind.-Wis.
12. Weirton-Steubenville, W.Va.-Ohio
13. York-Hanover-Gettysburg, Pa.
13. St. Louis-St. Charles-Farmington, Mo.-Ill.
13. Cincinnati-Middletown-Wilmington, Ohio-Ky.-Ind.
16. New York-Newark-Bridgeport, N.Y.-N.J.-Conn.-Pa.
16. Lancaster, Pa.
18. Merced, Calif.
18. Canton-Massillon, Ohio
20. Charleston, W.Va.
21. Washington-Baltimore-Northern Virginia, D.C.-Md.-Va.-W.Va.
22. Reading, Pa.
22. Hagerstown-Martinsburg, Md.-W.Va.
24. Indianapolis-Anderson-Columbus, Ind.
25. Louisville-Elizabethtown-Scottsburg, Ky.-Ind.