Double trouble: Wildfire smoke increasing the risk of COVID-19, experts warn


Gripped by a fourth wave of COVID-19, cases in Canada are surging again as parts of the country continue to grapple with another disaster: wildfires.

Over the past week, more than 21,000 new COVID-19 cases were reported across the country. British Columbia and Ontario – provinces that have borne the brunt of the wildfire season – are seeing a rise in new infections driven by the Delta variant.

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The overlap has raised concern that the burning forests may be contributing to the latest uptick in cases, according to some experts.

“Definitely, there are some factors that link the spread or the increase in transmissibility of the virus … to the fire,” said Dr. Horacio Bach, an infectious diseases expert at the University of British Columbia (UBC) in Vancouver.

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The dry conditions created by the wildfires coupled with the suspension of microscopic particles found in smoke – known as PM2.5 – can cause respiratory droplets to get trapped easily and move faster through the air, Bach explained.

Once bound with the smoke particles, the virus can then travel deep into the lungs, he told Global News.

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The convergence of the pandemic and the wildfire season has raised the overall health risk for Canadians, said Dr. Michael Mehta, professor of geography and environmental studies at Thompson Rivers University in Kamloops, B.C.

“Exposure to wildfire smoke will create an inflammatory response to the body, which weakens the immune system and makes people susceptible to a lot of different viruses and bacteria,” he told Global News.

As of Aug. 25, there were some 118 uncontrolled and 136 controlled active fires burning in different provinces, according to data from the Canadian Interagency Forest Fire Centre (CIFFC).

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The situation is particularly dire in B.C., where provincial health authorities have also re-imposed COVID-19 restrictions on the entire Interior Health region amid a rise in cases.

The displacement of many residents due to the wildfires has made containing COVID-19 especially challenging and put too much pressure on local health agencies, provincial health officer Dr. Bonnie Henry said on Aug. 20.

No clear link

While no clear link has been established, a number of factors can explain why we are seeing higher rates of COVID-19 in parts of B.C. that have been exposed to wildfires, said Mehta.

Wildfire smoke can increase coughing and sneezing, which can aid in COVID-19 transmission, he said.

Mass evacuations coupled with people spending more time indoors — in areas affected by wildfires —are also likely contributing to the spread, Mehta added.

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Like Canada, forest fires have wreaked havoc in the western United States.

A study by researchers at Harvard University earlier this month concluded that the increases in fine particulate matter (PM2.5) during the wildfire season last year may have contributed to excess COVID-19 cases and deaths in California, Oregon and Washington between March and December 2020.

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On average across all 92 western U.S. counties, the study found that a daily increase of 10 micrograms per cubic meter (µg/m3) in PM2.5 each day for 28 subsequent days was associated with an 11.7 per cent increase in COVID-19 cases, and an 8.4 per cent increase in COVID-19 deaths.

Both Mehta and Bach agreed a similar pattern could be brewing in Canada, but data is needed to support that hypothesis.

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“I don’t believe that we have the public health surveillance systems in place to actually make those conclusions, but there’s no reason to suspect that proportionally our levels would not be similar to what we’ve seen in that Harvard study,” said Mehta.

Health hazard and protection

In general, wildfire smoke is considered hazardous as it contains toxic particles, volatile gases and even organisms like bacteria and fungi.

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Exposure can cause a range of acute, short-term health risks, such as asthma, breathing difficulties and irritation of the eyes, nose and throat, as well as heart problems.

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Long-term impacts include chronic obstructive pulmonary disease (COPD), different types of cancers, as well as Type 2 diabetes.

Some serious complications associated with COVID-19 include pneumonia, respiratory failure, kidney failure and sepsis or systemic inflammation.

As a prevention, better ventilation and masking is important for both wildfires and COVID-19, Mehta said.

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He suggested using high-efficiency particulate air (HEPA) filters at home and in workplaces.

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The Public Health Agency of Canada (PHAC) recommends a three-layered non-medical mask with a filter to protect yourself and others from COVID-19.

In places most affected by wildfires, Mehta said an N95 respirator mask was a better option as it has an external valve that can reduce the risk of exposure to air pollution.

On the downside, though, these masks can increase the amount of respiratory droplets released, increasing the rate of COVID-19 spread for others.

Therefore, Mehta said people should consider doubling up their masks if they live in an area with high levels of community transmission of COVID-19 as well as wildfires.

© 2021 Global News, a division of Corus Entertainment Inc.