The advisories impact large areas of Idaho, Oregon, Montana and Washington, lasting through the end of January.

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 Air Quality Index measured 156 near Forks, Washington, and received a rating of "unhealthy," meaning some members of the ...

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 ...

After fires destroyed multiple neighborhoods across Los Angeles County, many residents looked up to find blue, smoke-free ...

As fires rage across the West Coast, destroying homes and forcing evacuations, the air we breathe has been severely impacted. In the following California air quality map, you can see how the air ...

Already known for having some of the worst air quality in the U.S., people in the area are now also at risk of inhaling smoke that contains harmful chemicals and byproducts that may cause long ...

The Air Quality Index, set by the Environmental Protection Agency, is your guide to how bad the air quality is outdoors. The ...