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

This measure, based on data from the Environmental Protection Agency, evaluates states on the number ... figures to determine the air quality a typical person in the state experiences, based ...

The Air Quality Index measured 156 near Forks, Washington, and received a rating of "unhealthy," meaning some members of the general public may experience health effects and members of sensitive ...

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 ...

Toxic smoke and dangerous particulate pollution are spreading far beyond the flames, leaving air quality at unhealthy levels in multiple counties.

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 the best states for air and ...