The service provides information based on a measure called the Air Quality Index, which gauges just how bad the air has become in a particular place. Having an understanding of the Air Quality ...

This measure, based on data from the Environmental Protection Agency, evaluates states on the number of days the Air Quality Index in counties was not rated “good.” U.S. News calculated a ...

The U.S. Air Quality Index (AQI) is a tool used by the U.S. Environmental Protection Agency to communicate with the public about outdoor air quality and health.The AQI includes six color-coded ...