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 ...

According to the US Environmental Protection ... 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.

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

PM2.5 is capable of traveling thousands of miles across the world on the wind — taking, for instance, about five days to reach the US from China ... The Air Quality Index, set by the ...