15 Most Polluted Cities in the United States in 2021
More than 20 million people, approximately 6.4% of the US population, live in one of the 15 countries where year-round particle pollution levels are worse than the national air quality limit. Here is a list of the 15 most polluted cities in the country according to particulate matter (PM 2.5) levels.
#1 Bakersfield, California
(annual PM2.5 of 17.6 μg/m3)
#2 Visalia, California
(annual PM2.5 of 16.6 μg/m3)
#3 Fresno-Madera-Hanford, California (annual PM2.5 of 16.6 μg/m3)
#4 San Jose-San Francisco-Oakland, California
(annual PM2.5 of 14.5 μg/m3)
5. Los Angeles-Long Beach, California
(annual PM2.5 of 14.2 μg/m3)
6. Medford-Grants Pass, Oregon
(annual PM2.5 of 13.9 μg/m3)
7. Fairbanks, Alaska
(annual PM2.5 of 13 μg/m3)
8. Phoenix-Mesa, Arizona
(annual PM2.5 of 12.8 μg/m3)
9. Chico, California
(annual PM2.5 of 12.2 μg/m3)
10. El Centro, California
(annual PM2.5 of 12.1 μg/m3)
11. Sacramento-Roseville, California
(annual PM2.5 of 11.9 μg/m3)
12. Cincinnati-Wilmington-Maysville, Ohio-Kentucky-Indiana
(annual PM2.5 of 11.6 μg/m3)
13. Indianapolis-Carmel-Muncie, Indiana
(annual PM2.5 of 11.5 μg/m3)
14. Pittsburgh-New Castle-Weirton, Pennsylvania-Ohio-Wyoming
(annual PM2.5 of 11.1 μg/m3)
15. Bend-Prineville, Oregon
(annual PM2.5 of 11 μg/m3)
