Study says wildfire smoke exposure may be linked to tumours — should you worry?
A doctor says the study measured overall exposure that was "extremely low compared to what is being seen in Canada and the U.S."
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Amid Canada’s worst wildfire season on record, an Australian study is shedding light on the long-term impacts of wildfire smoke.
The study, led by researchers at Monash University in Australia and published in the Journal of Hazardous Materials, states that prolonged exposure to wildfire smoke can lead to a 0.5 per cent increase in one's risk of dying from a tumour.
It also found that long-term exposure to wildfire smoke is associated with a 0.4 per cent higher risk of “all-cause mortality” which is a term that refers to a death as a result of any disease, complication or exposure.
Expert weighs in on link between wildfire smoke and tumours
Emergency physician Dr. Courtney Howard, based in Yellowknife, says the Australian study shows that in people between the ages of 38 and 73, a 10 mcg/m3 increase of wildfire-related PM2.5 exposure was associated with the 0.4 per cent higher risk of all-cause mortality.
“They measured this using a non-standard approach that examined 3-year cumulative PM2.5 exposure. Overall exposure was extremely low compared to what is being seen in Canada and the U.S.,” said Howard.
She explained that PM2.5 are tiny particles that can get deep down into people's lungs and cross over into the bloodstream, leading to inflammation.
The research states that “wildfires are growing in intensity, frequency and extent due to human-induced climate change” and although there have been studies done on wildfire exposure impact on health, “most of the evidence focused on short-term impacts.”
In Canada, there have been nearly 3,000 wildfires so far this year, and they’ve burned almost 8 million acres of land.
“Given the recent pollution levels in North America caused by the Canadian wildfires, our study linking long-term exposure to wildfire-related PM2.5 and mortality suggest that further research is urgently needed to provide more scientific evidence on this topic,” said lead researcher Associate Professor Shanshan Li, from the School of Public Health and Preventive Medicine, in a press release last week.
Wildfire smoke can impact your health, even at very low levels
According to the government of Canada website, there’s no evidence of a safe level of exposure for some of these pollutants. This means that smoke can impact a person's health even at very low levels.
“As smoke levels increase, your health risks increase. Air pollution may be present even when you can’t see or smell smoke,” the government said.
Li said she and her team aimed to estimate the long-term impacts of wildfire-related PM2.5 exposure on mortality in adults using a “large-scale national cohort database from the UK Biobank.”
UK Biobank “is a large-scale biomedical database and research resource, containing in-depth genetic and health information from half a million UK participants,” according to its website.
According to the study’s press release, the data used for the study came from 492,394 participants enrolled from 2004 to 2010.
A 2022 study from McGill University in Montreal echoed similar findings.
The study showed that people living within 50 kilometres of wildfires over the past 10 years had a 10 per cent higher incidence of brain tumours, and 4.9 per cent higher incidence of lung cancer, compared to people living further away.
'Further studies will need to be done': Doctor
Howard said that experts like herself have long been limited in what they can tell people about the long-term impacts of wildfire smoke.
“So few studies have been done to help us understand the long-term impacts of severe acute exposures, such as we are currently seeing in parts of the U.S. and Canada…further studies will need to be done,” she said.
How to protect yourself from wildfire smoke
How do you stay safe when air quality is low?
Dr. John Granton, a respirologist at the Toronto General Hospital, previously told Yahoo Canada that wildfires cause air pollution that can have a far-reaching effect on human health.
Granton said smoke isn't easy to escape, but there are some things people can do try and stay safe.
According to Granton, "there's not a lot of data to support the health benefits of masking" when it comes to safety from wildfire smoke. But, he said there is research looking into the effectiveness of filters.
"Cloth masks or scarves and things are not effective at all," the doctor claimed.
But, surgical masks and N95 filter masks "tend to filter those smaller particles," he added, "apparently some of those masks are effective."
Although filtration masks could aid in protecting your lungs from smoke, the top recommendation from experts is to stay indoors.
According to Health Canada, the following measures should also be taken:
Reduce sources of indoor air pollution (smoking, vacuuming, burning candles, wood stoves)
Prevent infiltration of outside air (seal windows, instal a high-quality air filter, set HVAC system to recirculation mode, limit use of exhaust fans when not cooking)
Have a functioning CO alarm
Use a portable air purifier and air conditioning
Granton echoed this advice.
"Most people recommend staying indoors as much as possible and not exercising or doing things outside," he reiterated.
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