How to better protect yourself from the health effects of wildfire smoke

Experts suggest planning, even after the air clears

A cyclist wears a mask during poor air quality conditions as smoke from wildfires in Ontario and Quebec hangs over Ottawa on Tuesday. (Sean Kilpatrick/The Canadian Press)

Photo: (Sean Kilpatrick/The Canadian Press)

As climate change intensifies and prolongs the hot, dry conditions for wildfires to thrive, Canadians can expect more summers of smoky skies. With that smoke, come serious potential health consequences for everyone, including children, older Canadians and people with pre-existing health conditions.

CBC News spoke to several health and climate experts who say that with proper planning, those risks can be mitigated. But it requires action before, during and even after the smoke clears.

A first step, say experts, can be to check the air quality forecast before stepping out the door.

What you can do is watch the AQHI, the Air Quality Health Index, and think about modifying your activity, advised Samantha Green, a family physician at Unity Health Toronto and incoming president of the Canadian Association of Physicians for the Environment.

Air Quality Health Index by region.

Photo: (CBC News)

Developed in partnership with Health Canada and the provinces, the AQHI updates (new window) twice a day and provides a risk rating on a scale of one to 10+ for many Canadian cities over today, tomorrow and the next day. One to three represents a low health risk, four to six is a moderate risk and seven to 10 is considered high risk. Very high pollution levels are considered 10+.

So perhaps don't go for that outdoor run if the AQHI is high, Green said.

The tool can be particularly useful for certain at-risk populations who may not be able to leave the house if air quality is too poor, allowing them to plan ahead.

If you are someone with an underlying health condition such as asthma, then you should pay even more attention to that AQHI, Green said. Think about even asking your doctor for a renewal of your inhaler in advance of wildfire smoke.

The most common advice during days of poor air quality is to stay indoors if possible, closing any potential ways smoke might enter your home.

What we're trying to do is encourage people to be cautious and to stay inside with the windows closed, with your ventilation running if you can, advised Dr. Courtney Howard, an emergency room physician in Yellowknife, who spoke to CBC News from Oxford, U.K.

A man waves to a sightseeing boat as he fishes across from the Port of Montreal on Monday. A smog warning is in effect for Montreal and multiple regions of Quebec due to forest fires.

Photo: The Canadian Press

Ventilation, in this case, can come in the form of air-cleaning devices that use high-efficiency air filters. While not all air filters are equally effective, they don't need to be expensive to work, says Jeff Brook, an associate professor who specializes in pollution, climate and health at the University of Toronto's Dalla Lana School of Public Health.

"Even simple do-it-yourself air cleaners (new window) can make a difference,said Brook, You can buy a box fan and a good MERV filter at Home Depot and assemble it. There's instructions online to make your own home indoor air cleaner."

Smoke density across Canada.

Photo: (CBC News)

Staying put for days may not always be realistic, Howard acknowledges, comparing the difficulty to the isolation experienced during the earlier months of the COVID-19 pandemic. But a pandemic-type solution still works for anyone who needs to venture out on smoky days.

One of the things you can do is get the N95 masks that are well fitted, Howard said. You can tell that it fits well [because] when you breathe in, the mask kind of sucks into your face. If you can feel the air coming around the sides, then it's not a good fit or you maybe need to mould it more to your face.

Even after the air quality advisories lift and the skies look clear, there's work to be done. Howard says smoke can seep inside a home unnoticed.

So what that means is that when the air clears again, make sure you open all the windows, Howard recommended. Let the smoky air that's built up inside your house out.

The specific risk from wildfires is exposure to ultrafine particles known as PM2.5. This is particulate matter that is 2.5 micrometres or smaller — on average, far less than the diameter of a human hair, according to the U.S. Environmental Protection Agency (new window).

WATCH | How wildfire smoke affects your health :

We haven't found a safe limit of exposure, explained Howard.

He called the smoke a toxic soup of these particles, whose exact composition differs depending on the materials being burned and the amount of heat. But it's the small size of the particles that allows them to penetrate deeper into our bodies.

It can go all the way down into our lungs, Howard explained, And not only cause topical irritation through all of our respiratory linings but actually cross over into our bloodstream and lead to inflammatory cascades.

Howard co-authored research published in the BMJ looking into the effect on emergency rooms in Yellowknife during the province's intense 2014 wildfire season. She and her colleagues found ER visits went up dramatically for people with asthma and pneumonia. They also found hospitalizations went up for people with chronic obstructive pulmonary disease (COPD).

Wildfire smoke blankets Kingston, Ont., Tuesday. Experts advise closing windows and other passageways for smoke to get inside your home during periods of poor air quality and airing out your home properly once the smoke clears.

Photo: (Dan Taekema/CBC)

Experts say the more often people are exposed to smoky air, the worse the health effects can get.

And that smoke harms not just young, developing lungs — including inside the womb — but can also exacerbate existing lung problems in the elderly.

As we age, we're more likely to be living with chronic lung conditions like asthma or COPD, explained Dr. Samir Sinha, director of geriatrics at Sinai Health and the University Health Network in Toronto.

He advises checking in and helping older Canadians make an emergency plan for the kind of days we've seen in the past week.

Along with the Canadian Red Cross, he's developed a practical emergency guide (new window) for older adults and their caregivers.

The best thing that we can do to stay out of harm's way is to have a plan.

WATCH | Wildfires have turned the air orange and the sun red. We explain why:

Anand Ram (new window) · CBC News · Senior Producer

Anand Ram is senior producer of the CBC's Health, Science and Climate units. He's worked as a reporter covering technology, business and the environment and as a producer with The National.

With files from Lauren Pelley