America's 25 Most Ozone-Polluted Metropolitan Areas, 2006
Updated February 21, 2017 | Factmonster Staff 
Ozone acts as a powerful respiratory irritant at the levels frequently found in most of the nation's urban areas during summer months. Symptoms include shortness of breath, chest pain when inhaling deeply, wheezing, and coughing. A study of a sample of longtime residents of Los Angeles, which has the highest and most frequent ozone problem in the nation, found that the group had a higher-than-expected loss of lung function over time.
| Rank | Metropolitan area |
|---|---|
| 1. | Bakersfield, Calif. |
| 2. | Los Angeles–Long Beach–Riverside, Calif. |
| 3. | Visalia-Porterville, Calif. |
| 4. | Fresno-Madera, Calif. |
| 5. | Merced, Calif. |
| 6. | Houston-Baytown-Huntsville, Tex. |
| 7. | Sacramento-Arden-Arcade-Truckee, Calif.-Nev. |
| 8. | Dallas–Fort Worth, Tex. |
| 9. | New York–Newark-Bridgeport, N.Y.-N.J.-Conn.-Pa. |
| 10. | Philadelphia-Camden-Vineland, Pa.-N.J.-Del.-Md. |
| 11. | Hanford-Corcoran, Calif. |
| 12. | Washington-Baltimore–Northern Va., DC-Md.-Va.-W.Va. |
| 13. | Modesto, Calif. |
| 14. | Knoxville-Sevierville–La Follette, Tenn. |
| 15. | Charlotte-Gastonia-Salisbury, N.C.-S.C. |
| 16. | Cleveland-Akron-Elyria, Ohio |
| 17. | Pittsburgh–New Castle, Pa. |
| 18. | Columbus-Marion-Chillicothe, Ohio |
| 19. | Raleigh-Durham-Cary, N.C. |
| 20. | Youngstown-Warren–East Liverpool, Ohio-Pa. |
| 20. | Cincinnati-Middletown-Wilmington, Ohio-Ky.-Ind. |
| 20. | Baton Rouge–Pierre Part, La. |
| 23. | San Antonio, Tex. |
| 24. | St. Louis–St. Charles–Farmington, Mo.-Ill. |
| 25. | South Bend–Mishawaka, Ind.-Mich. |
| 25. | Huntington–Ashland, W.Va.-Ky.-Ohio |
| 25. | Buffalo-Niagara-Cattaraugus, N.Y. |
Source: State of the Air: 2006, American Lung Association.
