San Francisco AQI
AQI
Health Implications
Cautionary Statement
0 - 50
Air quality is considered satisfactory, and air pollution poses little or no risk
None
51 - 100
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
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
Everyone 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
201 - 300
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.
301+
Health alert: everyone may experience more serious health effects
Everyone should avoid all outdoor exertion