The Post uses data from World Air Quality Index and updates the page every 15 minutes. Data for some cities may not update regularly.
|AQI||Air Pollution Level||Health Implications|
|0-50||Good||Air quality is considered satisfactory, and air pollution poses little or no risk.|
|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.|
|101-150||Unhealthy for Sensitive Groups||Members of sensitive groups may experience health effects. The general public is not likely to be affected.|
|151-200||Unhealthy||Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.|
|201-300||Very Unhealthy||Health warnings of emergency conditions. The entire population is more likely to be affected.|
|301+||Hazardous||Health alert: everyone may experience more serious health effects.|