These Were the 10 Most Polluted U.S. Cities in 2023

Los Angeles didn't make the top 10.

When it comes to air pollution, U.S. cities like Los Angeles get a bad rap for having poor air quality due to car smog and wildfires. But throughout all of 2023, some of the biggest cities in the country didn't even crack the top 10 as far as air pollution goes. 

Air quality product company IQAir examined air pollution data from cities and countries around the world in 2023 and compiled a list of the cities with the worst air quality imaginable. Nearly all of the 100 most polluted cities in the world last year were in India, and the study found that just seven countries on Earth breathe clean air, categorized as places with pollution of less than five micrograms per cubic meter of air. 

Here in the United States, the Pennsylvania township of Coraopolis outside Pittsburgh had the worst air quality last year with an average of 19.3 micrograms per cubic meter of air. That's quite a leap from second-place Forest Park, GA, an Atlanta suburb that lies next to the busiest airport in the world. 

The top 10 featured a number of cities across the Midwest, including Adrian, MI; Elwood, IL; and Huntington, IN. The only California area that made the list is the tiny town of Happy Camp in the northern part of the state; like Cave Junction, which lies across the Oregon border nearby, both areas were suffocated by wildfires last summer. 

Read up on the U.S.'s top 10 most polluted cities last year, and always check the air quality report in your area for any updates. 

1. Coraopolis, PA (19.3 µg/m³)
2. Forest Park, GA (17.6 µg/m³)
3. Cave Junction, OR (17.1 µg/m³)
4. Happy Camp, CA (16.8 µg/m³)
5. Adrian, MI (16.6 µg/m³)
6. Claymont, DE (16.5 µg/m³)
7. Robesonia, PA (16.3 µg/m³)
8. Attleboro, MA (15.8 µg/m³)
9. Elwood, IL (15.6 µg/m³)
10. Huntington, IN (15.5 µg/m³)