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 Air Quality Index (AQI) is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. For more ...

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 ...