Harrisburg, Pa. – Residents across Pennsylvania are being urged to limit outdoor activity as high levels of ozone and fine particulate matter prompt a statewide Air Quality Action Day through Thursday night.
According to the Pennsylvania Department of Environmental Protection, unhealthy air conditions are expected across multiple regions, including Philadelphia, Pittsburgh, Harrisburg, and the Lehigh Valley. Elevated temperatures, vehicle emissions, and stagnant air are combining to drive ground-level ozone and particle pollution to levels considered dangerous for sensitive groups — including children, older adults, and individuals with heart or lung disease.
The alert, issued as part of the Pennsylvania Air Quality Partnership program, warns that breathing outdoor air may be harmful during peak afternoon hours. Residents are encouraged to stay indoors, reduce vehicle use, and avoid burning wood or trash. PM2.5, a microscopic pollutant, can penetrate deep into the lungs and exacerbate respiratory issues. Ground-level ozone — often called smog — forms when sunlight “bakes” pollutants on hot summer days.
Communities in the Susquehanna Valley, Lehigh Valley, and Southwest PA are under particularly high risk, with color-coded warnings posted for each region. Local transit and environmental agencies have issued recommendations to limit energy use and postpone outdoor exercise.
Air Quality Alerts remain in effect until at least 8 p.m. Thursday. Additional warnings may be issued if conditions persist.
