The Air Quality Index (AQI) is an index for reporting daily air quality. It tells you how clean or polluted the air is around the United States, and what associated health effects might be of concern for the public. The AQI focuses on health effects that can be experienced within a few hours or days after breathing polluted air. EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide.
