No health impacts are expected when air quality is in this range.
(51-100)
Moderate
Unusually sensitive people should consider limiting prolonged outdoor exertion.
(101-150)
Unhealthy for Sensitive Groups
Active children and adults, and people with respiratory disease, such as asthma, should limit outdoor exertion.
(151-200)
Unhealthy
Active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion.
(201-300)
Very Unhealthy
Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion.
(301-500)
Hazardous
Health warning of emergency conditions: everyone is more likely to be affected.