Air Pollution and the Air Quality Index (AQI)

The EPA has developed a tool called the Air Quality Index (AQI) to help the public understand what the level of outdoor air pollution is on any given day. The AQI also communicates the potential health implications associated with different levels of air pollution.

The AQI uses a well-recognized color code scheme to convey to the public the severity of air pollution on a given day.

The table below shows the AQI levels.

Air Quality Index Levels of Health ConcernMeaning
GoodAir quality is considered satisfactory and air pollution poses little or no risk.
ModerateAir quality is acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
Unhealthy for Sensitive GroupsMembers of sensitive groups may experience health effects. The general public is not likely to be affected.
UnhealthyEveryone may begin to experience health effects; members of sensitive groups may experience more serious health effects.

Click here for the Center for Disease Control’s "Air Quality and Outdoor Activity Guidance for Schools" [0.3 MB pdf]

You can see today’s AQI and tomorrow’s forecast on the AQP homepage.