Residents warned to stay indoors as Canadian wildfire smoke hits Philadelphia region

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Philadelphia residents were hit with the smell of smoke and hazy skies as they made their way to work Thursday morning.

Health officials are warning people to limit their time outdoors as air quality across much of the U.S. reaches unhealthy levels because of wildfire smoke traveling from Canada.

Pennsylvania is under a Code Red Air Quality Action Day due to harmful air quality caused by high levels of particulate matter. These fine, tiny particles, known as PM 2.5, are 30 times smaller than the width of human hair, and are easily inhalable. The particles can settle deep in the lungs and enter the bloodstream.

Breathing in particulate matter can cause respiratory and cardiovascular problems, and impact vulnerable populations like children, the elderly and people with health conditions such as asthma.

“Wildfire smoke is among the most toxic air pollution that we can have,”  said Ruth McDermott-Levy, co-director of the Mid-Atlantic Center for Children’s Health and the Environment at Villanova University College of Nursing.

“That’s because it burns things like wood and other things that are not meant to be burned and breathed,” she said.

“It could be a camper, it could be a refrigerator, all kinds of things then become toxic pollutants that we breathe in, and as the wildfire travels, it picks up the other pollutants.”

More than 180 wildfires are burning in Canada, causing severe levels of smoke to travel more than a thousand miles — impacting multiple states in the U.S. Several wildfires are also burning in northern Minnesota.

Code Red alerts issued in Philadelphia region

At least 17 states have issued air quality alerts, including Pennsylvania, New Jersey and Delaware.

“As the airflow has turned more from the north and northwest in the lower levels and in the upper levels of the atmosphere, that has directed some of the smoke south and eastward, getting as far south as the mid-Atlantic area and places like Philadelphia,” said Paul Fitzsimmons, lead meteorologist at the National Weather Service in Mount Holly.

“Up until yesterday, the effects were largely to our north, at least in terms of any surface smoke,” he said. “But when we had a weak cold front come through last night, that caused the winds to shift more to the northwest, and that’s what brought the smoke down into this area.”

Fitzsimmons said possible thunderstorms late Thursday could improve air quality if they blow the smoke out. However, any subtle change in wind direction or atmospheric temperatures could cause conditions to change on an hourly basis, he said.

The smoke is expected to linger Friday, but conditions could improve Saturday, Fitzsimmons said.

“Getting into Saturday with the flow turning more from the south and west, that should tend to improve things,” he said. “Beyond Saturday, it gets very difficult to speculate. We will have another cold front coming through Sunday, but again, now we’re talking three days from now, and the smoke and how that’s going to play out gets very different once you get beyond 36 to 48 hours or so.”

The Philadelphia area is also facing a heat advisory as temperatures rise to the upper 90s, with humidity causing temperatures to feel like 100 degrees. The poor air quality and the heat are a potentially deadly combination, McDermott-Levy said.

She said during this time, people can experience a scratchy throat, irritated eyes and a runny nose. People should go to the emergency department if they experience chest pain and shortness of breath, McDermott-Levy said.

She encourages people to limit their time outdoors and avoid strenuous activity, and to set their air conditioning settings to recirculate at home and in their cars. McDermott-Levy also advises people to check on their neighbors, including people who might experience feelings of depression because they’re stuck indoors.

People should also avoid using gas-powered lawn equipment, eliminate the use of fireplaces and wood stoves, and avoid burning leaves, trash and other materials.

Philadelphia is no stranger to wildfire smoke. In 2023, the region was plagued by smoky, unhealthy air for five days, prompting schools to switch to virtual learning and causing delays at Philadelphia International Airport.

Residents can check AirNow for current conditions in their area.

The U.S. Environmental Protection Agency’s Air Quality Index issues color codes to report daily air quality. Green signifies good air quality, while yellow means moderate air quality. Orange represents unhealthy pollution levels for sensitive groups, and red warns of unhealthy pollution levels for all.