City Average Particulate Air Pollution (PM2.5)
Most Polluted Cities
Least Polluted Cities
All numbers are PM2.5 concentrations in μg/m3. City averages are based on regionally interpolated real-time monitoring station data. Individual neighborhoods and/or monitoring sites in the city may have somewhat more or less pollution. Only cities with at least 250,000 residents are included, and then only if real-time air quality monitoring data is available. Real-time data may contain errors and is subject to revision. Colors based on United States EPA Health Guidelines.