About This Ranking
This ranking is based on Air Quality Index (AQI) measurements from EPA monitoring stations across the United States. Cities with lower AQI values have cleaner air and better air quality.
What Makes Air Quality Good?
Cities with good air quality typically have favorable geography (coastal locations, good ventilation), lower population density, fewer industrial sources, stricter environmental regulations, and less vehicle traffic.
Data Sources
Rankings are based on current AQI data from the EPA AirNow system, which monitors air quality continuously.