Cities in California, Texas and Arizona are expecting air quality to become unhealthy for sensitive groups on Thursday.

The red-level air quality index (AQI) category—covering values from 151 to 200—means the air is unhealthy for everyone, not ...

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The EPA measures regional air quality index (AQI) by how hazardous it is to the general public. Discover the AQI in your city by searching below.

The map below displays the current air quality at monitoring sites in the U.S., Canada and Mexico. Air monitoring sites are color-coded based on the pollutant (ozone or particulate matter ...

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 quality of the air we breathe and the water we drink are critical aspects of leading a healthy, productive life. The air and water quality subcategory informs the best states for natural ...