Scranton, Pa., is the worst city in the U.S. for asthma, according to the Asthma and Allergy Foundation of America.

The foundation has released its “2006 Asthma Capitals” list. The annual list names the 100 U.S. cities the foundation considers to be the nation’s most challenging places to live for people with asthma.

Leading this year’s list are:

Scranton, Pa., Richmond, Va., Philadelphia, Atlanta, Milwaukee.

Before you read the full list, check out the standards used in formulating the list.

“Researchers developing this year’s rankings looked at 12 factors from three broad categories -- prevalence, risk, and medical factors,” states a foundation news release.

“All factors are weighted differently but the most important ones are the risk factors, which included annual pollution and ozone levels, pollen counts, public smoking bans, and more.”

Many cities on the list showed an above-average use of “rescue medications,” indicating that asthma patients weren’t properly managing their asthma, the news release notes.

Full Rankings

Here is a list of the 25 worst U.S. cities for asthma, starting with the worst:

1. Scranton, Pa.

2. Richmond, Va.

3. Philadelphia

4. Atlanta

5. Milwaukee

6. Cleveland

7. Greensboro, N.C.

8. Youngstown, Ohio

9. St. Louis

10. Detroit

11. Knoxville, Tenn.

12. Cincinnati

13. Toledo, Ohio

14. Canton, Ohio

15. Baton Rouge, La.

16. Pittsburgh

17. Little Rock, Ark.

18. Phoenix-Mesa, Ariz.

19. Memphis, Tenn.

20. Baltimore

21. Lancaster, Pa.

22. Chicago

23. Charlotte, N.C.

24. Houston

25. Harrisburg, Pa.

By Miranda Hitti, reviewed by Louise Chang, MD

SOURCES: Asthma and Allergy Foundation, “2006 Asthma Capitals -- The Most Challenging Places to Live with Asthma.” News release, Asthma, and Allergy Foundation of America.