One possible reason for bad air quality in the city is a fire that broke out yesterday afternoon in Lancaster, Pennsylvania, ...

If you have been hearing about poor air quality in New York City Friday, you can breathe a deep sigh of relief (literally): ...

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 ...

Angelenos still bothered by the smell of smoke may be surprised to see that Air Quality Index numbers returned to “healthy” or “moderate” levels this week in L.A. County, but they shouldn ...

The air quality index soared to 155, a level that Dr. Kari Nadeau, chair of the Department of Environmental Health at the Harvard T.H. Chan School of Public Health, likened to smoking up to about ...

NEW YORK -- If you think something seems off ... Then, the southwest wind carried it gradually into the Tri-State Area. The Air Quality Index (AQI) map supports the movement of the smoke.

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 ...