The 25 US Cities Doing the Most to Reduce Air Pollution

By Evan Comen • September 9, 2025

smoke billows from the stacks of smoke stacks

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The steady improvement in U.S. air quality over the past quarter century is one of the greatest public health successes in modern history. Average particulate matter levels in the United States have declined by 36.8% since 2000, with several major metropolitan areas achieving far larger reductions.

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In some cities – many of them manufacturing hubs in the South and Rust Belt – PM2.5 concentrations have been cut by more than half. Elsewhere, communities have managed to slash pollution while still absorbing rapid population growth. A closer look at historical EPA data reveals the U.S. cities with the greatest reductions in air pollution over the last 25 years.

To determine the cities reducing air pollution the most, Climate Crisis 247 reviewed historical data on air quality from the EPA. Metropolitan statistical areas were ranked based on the raw change in average annual PM2.5 concentration from 2000 to 2023. Supplemental data on population is from the U.S. Census Bureau.

25. Columbia, SC

Photo by Karolina Bobek on Unsplash

Average PM2.5 concentration, 2023: 8.0 µg/m³ (-7.9 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 15.9 µg/m³
Population change, 2000-2023: +32.4%
Total population: 856,889

24. Cleveland-Elyria, OH

Photo by Pixabay on Pexels

Average PM2.5 concentration, 2023: 9.9 µg/m³ (-7.9 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 17.8 µg/m³
Population change, 2000-2023: +0.5%
Total population: 2,158,932

23. Canton-Massillon, OH

Photo by Benjamin Lehman on Pexels

Average PM2.5 concentration, 2023: 10.7 µg/m³ (-7.9 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.6 µg/m³
Population change, 2000-2023: -1.8%
Total population: 399,474

22. Winston-Salem, NC

Photo by Paige Laine Elmer on Unsplash

Average PM2.5 concentration, 2023: 9.4 µg/m³ (-8.0 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 17.4 µg/m³
Population change, 2000-2023: +64.9%
Total population: 695,630

21. Lancaster, PA

Photo by Bryce Wendler on Unsplash

Average PM2.5 concentration, 2023: 9.8 µg/m³ (-8.0 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 17.8 µg/m³
Population change, 2000-2023: +18.7%
Total population: 558,589

20. Charlotte-Concord-Gastonia, NC-SC

Photo by Daniel Weiss on Unsplash

Average PM2.5 concentration, 2023: 8.3 µg/m³ (-8.1 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 16.4 µg/m³
Population change, 2000-2023: +110.8%
Total population: 2,805,115

19. Modesto, CA

Photo by Scott Blake on Unsplash

Average PM2.5 concentration, 2023: 10.5 µg/m³ (-8.2 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.7 µg/m³
Population change, 2000-2023: +23.4%
Total population: 551,430

18. Kingsport-Bristol-Bristol, TN-VA

Photo by Silviu Zidaru on Unsplash

Average PM2.5 concentration, 2023: 8.4 µg/m³ (-8.2 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 16.6 µg/m³
Population change, 2000-2023: +4.7%
Total population: 312,490

17. Lexington-Fayette, KY

Photo by Eva Varlioglu on Unsplash

Average PM2.5 concentration, 2023: 8.3 µg/m³ (-8.3 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 16.6 µg/m³
Population change, 2000-2023: +27.4%
Total population: 520,045

16. Fort Payne, AL

Photo by Primitive Spaces on Pexels

Average PM2.5 concentration, 2023: 8.9 µg/m³ (-8.3 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 17.2 µg/m³
Population change, 2000-2023: +12.6%
Total population: 72,569

15. Columbus, OH

Photo by Jordan Griffith on Unsplash

Average PM2.5 concentration, 2023: 9.9 µg/m³ (-8.3 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.2 µg/m³
Population change, 2000-2023: +35.2%
Total population: 2,180,271

14. Akron, OH

Photo by Leo_Visions on Unsplash

Average PM2.5 concentration, 2023: 7.5 µg/m³ (-8.7 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 16.2 µg/m³
Population change, 2000-2023: +0.5%
Total population: 698,398

13. Parkersburg-Vienna, WV

Photo by Matt Palmer on Unsplash

Average PM2.5 concentration, 2023: 8.9 µg/m³ (-8.9 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 17.8 µg/m³
Population change, 2000-2023: -46.8%
Total population: 87,628

12. Los Angeles-Long Beach-Anaheim, CA

Photo by Cedric Letsch on Unsplash

Average PM2.5 concentration, 2023: 9.9 µg/m³ (-9.0 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.9 µg/m³
Population change, 2000-2023: N/A
Total population: 12,799,100

11. Atlanta-Sandy Springs-Roswell, GA

Photo by ibuki Tsubo on Unsplash

Average PM2.5 concentration, 2023: 9.8 µg/m³ (-9.0 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.8 µg/m³
Population change, 2000-2023: +48.4%
Total population: 6,305,839

10. Asheville, NC

Photo by Ricky Beron on Unsplash

Average PM2.5 concentration, 2023: 6.4 µg/m³ (-9.0 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 15.4 µg/m³
Population change, 2000-2023: +13.0%
Total population: 417,202

9. Gainesville, GA

Photo by Sergio Rodríguez on Unsplash

Average PM2.5 concentration, 2023: 8.9 µg/m³ (-9.2 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.1 µg/m³
Population change, 2000-2023: +56.0%
Total population: 217,267

8. Bakersfield, CA

Photo by Fabio Sasso on Unsplash

Average PM2.5 concentration, 2023: 12.2 µg/m³ (-9.2 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 21.4 µg/m³
Population change, 2000-2023: +38.1%
Total population: 913,820

7. Chattanooga, TN-GA

Photo by Sarah Swainson on Unsplash

Average PM2.5 concentration, 2023: 9.1 µg/m³ (-9.3 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.4 µg/m³
Population change, 2000-2023: +21.8%
Total population: 580,353

6. Charleston, WV

Photo by Denitsa Kireva on Pexels

Average PM2.5 concentration, 2023: 8.8 µg/m³ (-9.3 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 18.1 µg/m³
Population change, 2000-2023: -34.4%
Total population: 203,259

5. Hickory-Lenoir-Morganton, NC

Photo by Mark Stebnicki on Pexels

Average PM2.5 concentration, 2023: 8.5 µg/m³ (-9.4 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 17.9 µg/m³
Population change, 2000-2023: +8.2%
Total population: 370,030

4. Gadsden, AL

Photo by Pixabay on Pexels

Average PM2.5 concentration, 2023: 9.8 µg/m³ (-9.7 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 19.5 µg/m³
Population change, 2000-2023: -0.2%
Total population: 103,241

3. Riverside-San Bernardino-Ontario, CA

Photo by Gabriel Tovar on Unsplash

Average PM2.5 concentration, 2023: 9.6 µg/m³ (-10.3 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 19.9 µg/m³
Population change, 2000-2023: +44.0%
Total population: 4,688,053

2. Birmingham-Hoover, AL

Photo by Zachary Farmer on Unsplash

Average PM2.5 concentration, 2023: 9.6 µg/m³ (-10.4 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 20.0 µg/m³
Population change, 2000-2023: +12.5%
Total population: 1,184,290

1. Portsmouth, OH

Photo by Michael & Diane Weidner on Unsplash

Average PM2.5 concentration, 2023: 8.8 µg/m³ (-12.3 µg/m³ from 2000)
Average PM2.5 concentration, 2000: 21.1 µg/m³
Population change, 2000-2023: -9.1%
Total population: 71,969

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