The Air Quality Index, set by the Environmental Protection Agency, is your guide to how bad the air quality is outdoors. The data that goes into the Air Quality Index comes from 5,000 air monitors ...

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 ...

and forecast models to provide real-time air quality index (AQI) readings for more than 1,000 locations. Los Angeles’ air quality is closely tied to weather patterns. Clear, breezy days help ...