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Trees, parks & the environment

Air quality

Current conditions in Philadelphia

AQI basics for ozone and particle pollution


Good — 0 to 50

Air quality is satisfactory, and air pollution poses little or no risk.


Moderate — 51 to 100

Air quality is acceptable. However, there may be a risk for some people, particularly those 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 less likely to be affected.


Unhealthy — 151 to 200

Some members of the general public may experience health effects. Members of sensitive groups may experience more serious health effects.


Very Unhealthy — 201 to 300

Health alert: The risk of health effects is increased for everyone.


Hazardous — 301 and higher

Health warning of emergency conditions: everyone is more likely to be affected.