51 - 100 |
Moderate |
Air 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. |
Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion. |
101 - 150 |
Unhealthy for Sensitive Groups |
Members of sensitive groups may experience health effects. The general public is not likely to be affected. |
Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion. |
151 - 200 |
Unhealthy |
veryone may begin to experience health effects; members of sensitive groups may experience more serious health effects |
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 |
101 - 150 |
Very Unhealthy |
Health warnings of emergency conditions. The entire population is more likely to be affected. |
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. |
300+ |
Hazardous |
Health alert: everyone may experience more serious health effects |
Everyone should avoid all outdoor exertion |