The Air Quality Index (AQI) is a
color-coded tool which shows air pollution levels. Green is good, yellow is moderate,
orange is unhealthy for sensitive groups, and red is unhealthy for all groups. DEQ issues
Air Pollution Advisories when we forecast
air pollution levels above the yellow, or moderate, AQI category and
remain there for more than 72 hours.
The AQI for particulate matter (both PM2.5 and PM10) is based
on the average of the previous 24 hours of pollution levels. Particle pollution
is often highest during the coldest times of the day, typically in the
evening and early morning.