Code Orange declared for Philly, suburbs due to poor air quality

The Philadelphia region on Friday will be under Code Orange Air Quality Action Day for Ozone.

The alert, issued Thursday by the state Department of Environmental Protection, includes Bucks, Chester, Delaware, and Montgomery counties.

Friday’s forecast calls for mostly sunny skies and temperatures in the low 90s, creating conditions for “robust ozone development” consistent with the Code Orange range during the afternoon, the DEP said.

Ozone, a gas that’s harmful when breathed in, forms from a combination of heat and different pollutants.

Under a Code Orange, air pollution concentrations may be unhealthy for vulnerable groups such as children, people with asthma, people with heart or lung disease, and older adults.

Local conditions may fall above or below Code Orange range. Residents are encouraged to visit AirNow.gov to check local conditions.