U.S. Department of State Air Quality Monitoring Program

Air Quality
Health Effects Statement
Cautionary Statement

Good
(0-50)
Air quality is satisfactory, and air pollution poses little or no risk.
None.

Moderate
(51-100)
Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. (See below for sensitive groups.))
Unusually sensitive people should consider limiting prolonged outdoor exertion.

Unhealthy for Sensitive Groups
(101-150)
Members of sensitive groups may experience health effects. The general public is less likely to be affected.
Sensitive groups should reduce prolonged or heavy outdoor exertion. Schedule outdoor activities in the morning when ozone is lower.

Unhealthy
(151-200)
Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
Sensitive groups should avoid prolonged or heavy outdoor exertion. Everyone else should reduce prolonged or heavy outdoor exertion.

Very Unhealthy
(201-300)
Health alert: The risk of health effects is increased for everyone.
Sensitive groups should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy outdoor exertion.

Hazardous
(301-500)
Health warning of emergency conditions: Everyone is more likely to be affected.
Everyone should avoid all outdoor exertion.

Beyond Index
(>500)
Extremely High Levels: Avoid all physical activity outdoors.

Sensitive Groups
PM2.5: People with heart or lung disease, older adults, and children. For more information, click here.
Ozone: People with lung disease, children, older adults, and people who are active outdoors, including outdoor workers. For more information, click here.