US Air Quality Map
Interactive map showing real-time and annual air quality data across all 50 states. Each county is color-coded by EPA Air Quality Index (AQI) category — from green (good) to maroon (hazardous). Toggle between current hourly readings from AirNow monitoring stations and annual averages based on EPA historical data.
Understanding the Air Quality Map
How to Read the Map
Each county is shaded according to the EPA's Air Quality Index scale. Toggle between Current mode — real-time readings from AirNow monitoring stations updated hourly — and Annual mode showing typical conditions based on the most recent full year of EPA data.
Click any county or city marker to jump to its detailed air quality page with current AQI, 5-day forecast, pollutant breakdown, and historical trends.
AQI Color Scale
- Good (0–50) — Little or no health risk
- Moderate (51–100) — Acceptable; some risk for unusually sensitive people
- Unhealthy for Sensitive Groups (101–150) — Sensitive groups may experience health effects
- Unhealthy (151–200) — Everyone may begin to experience health effects
- Very Unhealthy (201–300) — Health alert — serious effects for everyone
- Hazardous (301+) — Emergency conditions — avoid all outdoor exertion
Data Sources
Current readings come from the EPA's AirNow monitoring network, refreshed every hour. Annual averages use EPA Air Quality System (AQS) data — the same source used for regulatory reporting.
Coverage
The map covers all 50 US states. Not every county has an active monitoring station — counties without sensors may show estimated values or appear uncolored in current mode.
Explore Rankings
Want to compare cities directly? View the cleanest cities or most polluted cities ranked by median AQI.