Air Quality Index
The Air Quality Index (AQI) is a key tool used to communicate the quality of the air. The AQI ranges from 0 to 500, with higher values indicating greater levels of pollution and associated health risks. The Environmental Protection Agency (EPA) has established an AQI for five major air pollutants regulated under the Clean Air Act: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide.
AQI values of 100 or below are generally considered satisfactory. When AQI values exceed 100, air quality starts to become unhealthy, initially for sensitive groups, such as individuals with asthma, and progressively for the general population as the AQI values increase.