US Cities with Worst Air Quality Overall

Cities with the most polluted air based on 2025 EPA monitoring data. These communities face the greatest health risks from air pollution.

Health Impact

40.9M
People in highly polluted areas
8
Avg unhealthy days per city
2122
Highest AQI recorded
Showing 1–1 of 1 cities
  1. #1

    Portland, ME

    Population: 210,907Monitored: 304 days
    A
    Median: 39
    Good:225
    Moderate:74
    Sensitive:5
    Unhealthy:
    Very Unhealthy:
    Hazardous:

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