Air Quality Alert Issued for Mon Valley, Allegheny County, Pennsylvania

The Allegheny County Health Department has issued a Mon Valley Episode Watch for Tuesday, October 20, 2026, in conjunction with a Code Orange Air Quality Alert from the Pennsylvania Department of Environmental Protection. The alert is for fine particulate matter (PM 2.5), indicating unhealthy air for sensitive groups due to high pressure trapping pollutants. Sensitive individuals are advised to reduce outdoor physical exertion.