The Pennsylvania Department of Environmental Protection issued a Code Red air quality warning for the entirety of the state Wednesday morning, with wildfires in eastern Canada contributing to “concentrations of fine particulate matter.”

Shannon Hefferan, a meteorologist with National Weather Service Pittsburgh, said people of Butler County may have noticed the sky being a bit hazy recently, which is a trend that is likely going to continue until the end of the week.

“We're pretty much still under this pattern where we have winds coming in from the north,” Hefferan said. “That's why we've been having smoke come down, because of wildfires in Quebec.”

AirNow, a partnership of the U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration and more, said people with heart or lung disease, older adults, children and teens should be careful during code red air quality alerts. The service recommends people in those demographics avoid strenuous outdoor activities or move physical activities indoors or reschedule them.