Wildfire smoke: Best ways to protect yourself and your family as air quality worsens

A thick blanket of acrid smoke has descended on Toronto and much of southern Ontario, the product of raging forest fires in northeastern Ontario and Quebec.

Air quality in the region has plummeted and by Tuesday evening, Toronto’s air quality ranked among the worst in the world.

There’s little relief on the horizon for the millions of residents living in the affected areas, as Environment Canada and the Province of Ontario forecast Wednesday that poor air quality will persist into the weekend.

“High levels of air pollution have developed due to smoke from forest fires,” reads the special air quality statement, issued Wednesday morning. “Smoke plumes from forest fires in Quebec and northeastern Ontario have resulted in deteriorated air quality.”

As of Wednesday at 10 a.m., Toronto’s air quality health index was at a level 4, indicating a “moderate risk” to health. However, by Wednesday afternoon, that value is expected to climb to a level 7, denoting a “high risk.”

The smoke and pollution are expected to worsen into Thursday with a predicted change in the wind direction likely to bring more of the Quebec wildfire smoke over the GTA, said David Phillips, a senior climatologist with Environment Canada. The federal department predicts the air quality index in Toronto will climb to a level 9 that day.

With smoke in the forecast all week, here are some tips on how to protect you and your family from the debilitating pollution.

“Make sure that you’re not overexerting yourself and getting exposed to more smoke,” recommends Jeff Brook, an associate professor at the University of Toronto’s Dalla Lana School of Public Health and Department of Chemical Engineering and Applied Chemistry. “Take it easy.”

While the tip applies to everyone, it’s especially important for those who are at increased risk of experiencing negative health effects, such as older adults, pregnant people and individuals with lung or heart conditions.

Children, who often are encouraged to go out and play, are also “more susceptible to smoke for a number of reasons,” said Laura Kate Bender, the American Lung Association’s national assistant vice president of healthy air, in an interview with the Associated Press. “Their lungs are still developing, they breathe in more air per unit of body weight.”

Schools in Toronto and the GTA have started taking steps to minimize exposure, including indoor recess and cancelling outdoor events.

Because the smoke contains fine particulate matter, Brook recommends wearing an N95 mask that fits snugly around the nose and mouth. A standard surgical mask could also work — though less effectively — if N95 masks are unavailable or if people find themselves taking off an N95 mask more often than they’re wearing it.

“Every reduction in breathing this stuff provides a benefit to your health,” Brook added.

Much of the air pollution produced by the forest fires is known as PM2.5 — fine particles of matter with a size of 2.5 microns or less. Just how tiny are they? You can fit thousands of them into the period at the end of this sentence.

Because of their size, the particles can pass into the blood, causing a system-wide inflammation that can exacerbate heart conditions and potentially cause cancers. Masks, especially an N95 respirator, can prevent much of that particulate matter from being inhaled.

If the temperature in your home is comfortable, close all windows and doors to reduce the amount of air pollution coming indoors, said Environment Canada in its special air quality statement.

If you are uncomfortable at home, you can also temporarily relocate to a location with clean, cool air, such as a library, shopping mall or community centre.

Air quality can vary considerably from hour to hour, so it’s important to regularly check current levels to see when it’s best to open windows and doors.

Use an air purifier with a High-Efficiency Particulate Air (HEPA) filter to keep indoor air clean, recommends Environment Canada. While closing windows and doors does help, it doesn’t entirely prevent these small particles from coming indoors, said Brook.

“Houses tend to be leaky enough and these particles are so small. They’ll make their way in eventually,” he said.

When installing a purifier, it’s key to ensure the capacity of the filter fits the volume of the space. However, you don’t need to install an air purifier for every room, Brook noted, just the rooms where you spend the bulk of your time.

This may sound surprising, but using kitchen or bathroom fans that vent outside may inadvertently draw more exterior air into your home. Why? The negative air pressure created by these ventilation systems will draw in wildfire smoke, even through the cracks and crevices in your home if windows are shut.

Joshua Chong is a Toronto-based staff reporter for the Star’s Express Desk. Follow him on Twitter: @joshualdwchong