Air Quality Index Levels of Health Concern | Numerical Value | Meaning | ||
Good | 0 to 50 | Air quality is considered satisfactory, and air pollution poses little or no risk | ||
Moderate | 51 to 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. | ||
Unhealthy for Sensitive Groups | 101 to 150 | Members of sensitive groups may experience health effects. The general public is not likely to be affected. | ||
Unhealthy | 151 to 200 | Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects. | ||
Very Unhealthy | 201 to 300 | Health alert: everyone may experience more serious health effects | ||
Hazardous | 300 to 500 | Health warnings of emergency conditions. The entire population is more likely to be affected. |