Best & Worst Cities for Ozone Pollution


This information has been reviewed and approved by Lisa Maier, MD (July 2026).


Summary: Best and Worst Cities for Ozone Pollution

Worst Cities by Ozone

1: Los Angeles-Long Beach, CA
2: Visalia, CA
3: Bakersfield-Delano, CA
4: Phoenix-Mesa, AZ
5: Fresno-Hanford-Corcoran, CA
6: Houston-Pasadena, TX
7: San Diego-Chula Vista-Carlsbad, CA
8: Denver-Aurora-Greeley, CO
9: Dallas-Fort Worth, TX-OK
10: El Centro, CA
11: Las Vegas-Henderson, NV
12: New York-Newark, NY-NJ-CT-PA
13: Salt Lake City-Provo-Orem, UT-ID
14: San Jose-San Francisco-Oakland, CA
15: Chicago-Naperville, IL-IN-WI
16: El Paso-Las Cruces, TX-NM
17: Sacramento-Roseville, CA
18: Fort Collins-Loveland, CO
19: Albuquerque-Santa Fe-Los Alamos, NM
20: Sheboygan, WI
21: Tulsa-Bartlesville-Muskogee, OK
22: Louisville-Jefferson County-Elizabethtown, KY-IN
23: Milwaukee-Racine-Waukesha, WI
24: Boise City-Mountain Home-Ontario, ID-OR
25: St. Louis-St. Charles-Farmington, MO-IL

Cleanest Cities by Ozone

1. Augusta-Richmond County, GA-SC
2. Bangor, ME
3. Bellingham, WA
4. Brunswick-St. Simons, GA
5. Charleston-Huntington-Ashland, WV-OH-KY
6. Charlottesville, VA
7. Chico, CA
8. Crestview-Fort Walton Beach-Destin, FL
9. Fairbanks-College, AK
10. Florence, SC
11. Fort Smith, AR-OK
12. Gadsden, AL
13. Gainesville-Lake City, FL
14. Greenville-Washington, NC
15. Idaho Falls-Rexburg-Blackfoot, ID
16. Ithaca-Cortland, NY
17. Johnson City-Kingsport-Bristol, TN-VA
18. Mayaguez-Aguadilla, PR
19. McAllen-Edinburg, TX
20. Middlesborough-Corbin, KY
21. Missoula, MT
22. Monroe-Ruston, LA
23. Montgomery-Selma, AL
24. Myrtle Beach-Conway, SC
25. Palm Bay-Melbourne-Titusville, FL

Source: American Lung Association 2025

 

What is Ozone Pollution?

Bad or ground-level ozone pollution is created when vehicle and other emissions mix with pollutants and are heated by the sun. Warmer weather increases ground-level ozone pollution.

What Makes Air Quality Unhealthy?

The Air Quality Index (AQI) grades air quality based on ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide or nitrogen dioxide levels. Visit airnow.gov or watch local alerts.

Protect Your Lungs from Ozone Pollution

  • Watch local air quality advisories.
  • Ozone levels are always lower in the morning, so plan outdoor activities accordingly.
  • The elderly, the very young and those with lung disease are at the highest risk from severe ozone pollution and should limit afternoon outdoor time during poor ozone days
  • Keep windows closed.
  • Take medications exactly as prescribed.
  • Use the circulate setting on your home thermostat to keep polluted air out.
  • Call your doctor if symptoms increase or if you need more medication.

Facemasks are highly encouraged to limit COVID-19 infection but provide no protection against ozone pollution.

 

More Information on Pollution


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