Air quality expert explains the health risks of wildfire smoke and how to stay safe.
As drifting smoke from wildfires in northern Ontario turns skies in southern Ontario and beyond an eerie, orange colour in the middle of a heatwave, an air quality expert at the University of Waterloo is renewing warnings for residents to take some simple steps to help protect themselves from potential harm to their health.
Dr. Rebecca Saari, a professor of civil and environmental engineering and Tier 2 Canada Research Chair in Global Change, Atmosphere and Health, studies the immediate and long-term health consequences of climate change, climate policies and major contributors to poor air quality such as wildfires.
What are the immediate health risks to people in Canada and the U.S. experiencing poor air quality due to the current wildfires in northern Ontario?
People may experience various symptoms, including irritation of the nose and throat, coughing and headaches. Numerous studies have shown specific links between smoke from wildfires and respiratory symptoms. People with underlying health issues, especially respiratory and cardiovascular illness, are at higher risk for more serious outcomes, like asthma attacks that may require hospitalization, as are children and older adults.
Why are built-up areas quite far from the actual fires seeing such obvious effects and evidence of smoke in the air?
Wind patterns can carry smoke directly from the fires to populated regions. Fires emit smoke particles and other harmful pollutants that can form haze or smog. Particles in the air settle to the ground depending on their size, with large particles settling quickly and small, submicron particles remaining suspended in the air for several weeks unless they are removed by other processes, such as rain. This means fires can affect air quality both locally and across continents. These hot, sunny, dry days are conducive to fires, haze and smog.
What long-term health risks are associated with prolonged or repeated exposure to poor air quality caused by wildfires?
Evidence suggests the long-term risks are serious, with Health Canada estimating that 17,000 Canadians die prematurely each year due to exposure to air pollution, along with more than 35 million person-days of acute respiratory symptoms annually. The current estimated economic burden of air pollution in Canada is more than $140 billion per year. Wildfires are the largest contributor to particulate matter, the pollutant that causes the greatest harm to public health. One recent study estimated that wildfire smoke causes annual health damages ranging from about $500 million to more than $6 billion in Canada.
What steps can people take to protect themselves during the summer fire season?
It is important to pay attention to air quality alerts and follow the guidance provided by the Air Quality Health Index. This typically means reducing exposure by limiting time outdoors during severe pollution episodes, especially for vigorous physical activity. When indoors, keep doors and windows closed and use filtration, such as a central HVAC system with an air filter or an indoor air purifier. If you cannot otherwise avoid exposure, consider wearing a well-fitting N95 mask that provides protection from smoke particles.
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