This spring, raging wildfires across Quebec and Ontario have led to poor air quality in major cities across the U.S. and Canada, including New York, Ottawa, and Toronto.
In fact, on June 6, Toronto was the fourth-most polluted major city in the world, with wildfire smoke enshrouding the city and placing it below Montreal, Detroit, and Delhi, India. Poor air quality prompted many schools in the GTA to move recess indoors and cancel strenuous outdoor activities. City-run daycares also suspended outdoor activities, and the Toronto Zoo reduced its operating hours amid the smoky conditions.
Devastation nationwide
Across Canada, this year’s fire season has resulted in 3.7 million hectares burned so far – six times the area of Prince Edward Island. The latest devastation comes two years after Canada endured one of the most destructive wildfire seasons ever recorded, with more than 6,000 wildfires burning from coast to coast.
In the wake of the wildfires and the pollution they cause, Dr. John Granton, a consultant respirologist in the Division of Respirology at UHN, has provided answers to questions concerning their far-reaching impact on health and what we can do to best protect ourselves.
What makes the air pollution caused by wildfires dangerous?
As the air quality index worsens, exposure to pollutants in the air increases. It is not so much what you taste – which can irritate your upper airway – but those smaller particles and gases that reach the lower airways that cause health problems.
Small air pollutant particles in the smoke are called PM2.5 particles. This is where a lot of the toxic content resides. Because these particles are not filtered by your upper airway, they not only gain access to your lower airway but to your bloodstream as well. This can cause asthma attacks and heart attacks, and can contribute to hospitalizations and long-term health outcomes. Even the smell alone can cause problems.
What can we do to protect ourselves?
If you have an underlying health condition and the pollution index is high, the best approach is to stay indoors as much as possible, keep your windows closed, and remain in an air-conditioned environment. Use an air purifier if you have one – preferably one with a non-ozone producing HEPA filter.
If you need to go outside, try to minimize the time you spend outdoors and reduce the amount of strenuous activity you do. If you have a serious health condition and must be outside, it is recommended to use a properly fitted N95 mask.
Who is most susceptible to pollution?
People with underlying lung conditions are at the greatest risk of pollution’s adverse health effects. Unfortunately, many individuals who are also at risk in our society are those who cannot escape from it. These include people who are homeless and don’t have access to sheltered spaces where they can close windows and use air purifiers.
Fortunately, for most people, shorter-term exposure will likely not cause any health problems. However sustained exposures to poor air quality over many days to weeks can lead to long term risks, even for healthy people.
Can face masks alone protect us from wildfire smoke?
There is not a lot of data to support the health benefits of masking when it comes to protection from wildfire smoke, although research is examining the effectiveness of filters. While cloth masks, scarves, and similar items are not at all effective, surgical masks and N95 masks tend to filter smaller particles.
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