The Air Quality Index (AQI) Scale

The AQI scale to report the daily air quality across the United States. The scale is used to inform the public about how clean or unhealthy the air is at a specific location. The scale, which ranges from 0 to 500, provides a measure of the concentration of five major ground level and airborne pollutants and health impacts experienced with breathing the air. The AQI is set based on the highest amount of one of the major pollutants; so the lower the value, the cleaner the air. According to the EPA, any AQI value under 100 is considered satisfactory.