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 ...

We put indoor air quality through our scientific testing to find which models work—and which models don’t. View our ratings and reviews to find the best indoor air quality monitors.

Depending on the different pollutants in the air, like pollen or wildfire smoke, some days can be easier to breathe than ...

It comprises two measures: the number of days with an air quality index below a certain threshold and the number of violation points against drinking water systems in each state. Learn more about ...

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 ...