AirNow is a one-stop source for air quality data. The recently redesigned site highlights air quality in your local area first, while still providing air quality information at state, national, and world views. A new interactive map lets you zoom out to get the big picture or drill down to see data for a single air quality monitor.
AirNow reports air quality using the official U.S. Air Quality Index (AQI), a color-coded index designed to communicate whether air quality is healthy or unhealthy for you. When you know the AQI in your area, you can take steps to protect your health.