Allegheny County Health Department Issues Mon Valley Episode Watch for Poor Air Quality

The Allegheny County Health Department has issued a Mon Valley Episode Watch for Tuesday, October 20, 2026, coinciding with a Code Orange (Unhealthy for Sensitive Groups) Air Quality Alert from the Pennsylvania Department of Environmental Protection. High pressure is expected to trap pollutants, leading to elevated levels of fine particulate matter (PM 2.5) that can pose health risks, especially for individuals with heart or lung disease, older adults, children, and pregnant women.