Smoke from wildfires in northern and western Canada has drifted thousands of miles east, resulting in hazy skies earlier this week and forcing the state Department of Environmental Protection on Tuesday to issue an air quality alert in Washington, Fayette, Allegheny, and four other surrounding counties.
The Code Orange Air Quality Action Day was issued in 13 other counties across the state.
A news release from the DEP said light winds that carried smoke from the fires likely contributed to “daily average concentrations of fine particulate matter in the Code Orange range.”
A Code Orange alert means sensitive groups – such as people with asthma, heart disease or lung disease – may be exposed to unhealthy levels of pollution in the air.
A cold front moved in Wednesday and will clear out smoke from the area, a meteorologist from the National Weather Service said.
However, that reprieve is likely to end Thursday night, as wind shifts are forecast to bring more smoke and particulates into the region.
“We’ll see a temporary break from that haziness, but there will be an increase in smoke and haze coming in later (Thursday) and Friday, and it will be hazy again this weekend,” said Accuweather meteorologist Paul Walker.
In addition to causing hazy skies, the dense smoke in the atmosphere has resulted in the sun appearing bright orange-red at sunrise and sunset.
“The sunrise, especially, looked like a ball of fire,” said Walker.
Last year, multiple large wildfires burned in western states and Canada, which, like this week, impacted air quality thousands of miles away.
The phenomenon is unlikely to end anytime soon, Walker said.
A historic drought and record-setting heat early in the summer are contributing to a dangerous fire season.
“As long as it remains dry, and the Northwest continues to be in drought conditions, we’ll continue to have fires and we’ll have continued episodes of smoke and haze,” he said.
In the U.S., there are currently 78 wildfires burning – including 61 large, uncontained fires – in 13 states, according to the National Interagency Fire Center. In Canada, there are 297 active fires, according to the British Columbia Wildfire Service.