The AQI reports on five major air pollutants: ozone, particulate matter, sulfur dioxide, carbon monoxide and nitrogen dioxide. An AQI value is given for each monitoring site and pollutant. The overall AQI for a site is the highest index value of any of the pollutants. As levels of any or all of these air pollutants rise beyond health standards, precautionary health warnings are triggered.

Please click on the county groups for AQI reports in that area. The AQI reports are updated hourly at half-past the hour. The AQI reports use the following key to describe Air Quality

Northwest PA Southwest PA Central PA Northeast PA Lehigh Valley Susquehanna Southeast PA

Color	AQI	Air Quality
Green	0-50	Good
Yellow	51-100	Moderate
Orange	101-150	Unhealthy for Sensitive Groups
Red	151-200	Unhealthy
Purple	201-300	Very Unhealthy
Maroon	>300	Hazardous