| 0-50 |
Good |
Air quality is considered satisfactory, and air pollution poses little or no risk. |
Minimal impact on health. |
General public and sensitive individuals continue normal activities. |
| 51-100 |
Satisfactory |
Air quality is acceptable; however, there may be a moderate health concern for a very small number of people who are sensitive to air pollution. |
Minor breathing discomfort to sensitive people. |
Sensitive individuals should consider reducing prolonged or heavy exertion. |
| 101-200 |
Moderate |
Air quality is acceptable; however, some pollutants may cause moderate health concerns for a number of people who are unusually sensitive to air pollution. |
Breathing discomfort to people with lung disease, children, and older adults. |
People with respiratory or heart conditions, children, and older adults should limit prolonged exertion. |
| 201-300 |
Poor |
Health alert: everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects. |
Breathing discomfort to most people on prolonged exposure. |
Everyone should avoid prolonged or heavy exertion; particularly sensitive groups should limit outdoor activities. |
| 301-400 |
Very Poor |
Health warnings of emergency conditions. The entire population is more likely to be affected. |
Respiratory illness on prolonged exposure. Effects may be more pronounced in people with lung and heart diseases. |
Everyone should avoid outdoor activities; sensitive groups should stay indoors and keep activity levels low. |
| 401-500 |
Severe |
Serious health effects, even for the general population. |
Affects healthy people and seriously impacts those with existing diseases. |
Everyone should avoid all outdoor exertion; sensitive groups should remain indoors and keep activity levels low. |