Code Orange Air Quality Alert Declared In PA Due To Wildfire Smoke, Heat

A Code Orange Air Quality alert has been declared Thursday by the Pennsylvania Department of Environmental Protection across the Philadelphia area (Bucks, Chester, Delaware, Montgomery, and Philadelphia counties) and in southwest Pennsylvania counties (Allegheny, Westmoreland, Beaver, Butler, Armstrong, Washington, and Fayette).

According to sources, low level smoke from Canadian wildfires coupled with high temperatures around 90 degrees will produce "significant" ozone concentrations in the code orange range Thursday afternoon. "Sensitive individuals of the population should take precautions and limit outdoor activity during the afternoon," the alert said.

The U.S. Environmental Protection Agency’s Air Quality Index (AQI) uses color codes to forecast and report daily air quality. The orange zone represents an AQI of 101 to 150. In this zone, sensitive groups, including children, the elderly and those with respiratory problems, could experience unhealthy pollution levels.

The red zone, 151-200, warns of unhealthy pollution levels for all.

The AQI forecast for Philadelphia on Thursday is 103. In Pittsburgh, it is 102.

Ozone forms when sunlight triggers a chemical reaction between airborne pollutants like nitrogen oxides and volatile organic compounds. While these ozone-forming pollutants typically come from vehicle exhaust and industrial emissions, wildfire smoke can also contribute to their presence. Ozone pollution is most prevalent in densely populated regions, where traffic and industrial activity are concentrated.

Residents and businesses within the alert area are strongly encouraged to voluntarily help reduce ozone air pollution by driving less by carpooling or using public transportation, reducing vehicle trips and limiting engine idling, and refueling cars and trucks after dusk. Additionally, residents are asked to conserve electricity by setting air conditions to a higher temperature and turning off lights that are not in use.