Wildfire smoke from Canada and Minnesota began pushing into Pennsylvania’s southern and eastern counties on Wednesday, creating Code Red concentrations of PM2.5.
Unhealthy Code Red concentrations of PM2.5 will occur throughout the day on Thursday, with some hours of very unhealthy Code Purple concentrations possible, according to the Pennsylvania Department of Environmental Protection. Light winds associated with weak high pressure moving in from the north will act to trap pollutants near the surface keeping air quality in an unhealthy range, the DEP says.