When will the smoke clear in pa? On Thursday and Friday, smoke from more than 800 wildfires burning in Canada pushed unhealthy air into the U.S., with more than 100 million people affected. Chicago, Detroit, Milwaukee, Pittsburgh and Washington all saw Air Quality Index readings above 200 on Friday.
As of Thursday, Canada had more than 800 actively burning fires, including large clusters in Ontario near the border with Minnesota. A heat wave across North America was trapping the smoke and carrying it south, adding to already poor air in places far from the fires themselves.
Suzanne Paulson on wildfire smoke
Suzanne Paulson, director of the Center for Clean Air at the University of California, Los Angeles, said wildfire smoke poses a different problem than routine urban pollution. “No particles are good to breathe, but wildfire particles seem to be more toxic than regular urban particles themselves,” she said.
She also warned that residents should not read the Air Quality Index too literally when smoke is present. “Whatever the [AQI] color is, consider that it’s the next color up if there’s a lot of wildfire smoke,” Paulson said.
Philadelphia and New York
The Environmental Protection Agency uses the Air Quality Index to assess polluted air, and scores of 100 or more mean the air is unhealthy and could harm people’s health. On Friday afternoon, parts of Michigan, Ohio and Wisconsin had AQI readings in the 300s, while Chicago, Detroit, Milwaukee, Pittsburgh and Washington were above 200.
New York launched emergency operations on Wednesday, and Philadelphia city officials suspended trash pickup and closed public pools on Friday. Serap Erdal, a professor at the University of Illinois, Chicago and project leader of Open Air Chicago, said, “Just because we’re indoors doesn’t mean we’re not inhaling outdoor air.”
PM2.5 and indoor air
PM2.5 particles can be deeply inhaled, penetrate the lungs and enter the bloodstream, which is why experts say staying indoors and avoiding physical activity outside is the best protection in areas with exceptionally high Air Quality Index readings. That advice still leaves one practical question for Pennsylvania readers: indoor air may filter some smoke, but the haze outside can keep seeping into daily routines until the broader smoke plume eases.
