More than 6,000 wildfires burned across Canada in 2023, torching an area larger than England the country's most destructive fire season ever. In communities such as Yellowknife, Toronto and New York City, the sky turned an eerie orange in the middle of the day, whether there were fires nearby or hundreds of kilometres away.
A study published in Nature estimated that from June 26 to July 7, 2023, exposure to wildfire smoke caused 5,400 acute deaths in North America. Over the course of the year, the smoke was responsible for 82,100 premature deaths worldwide.
While the last two years have not been as devastating as 2023, the higher temperatures and widespread drought conditions caused by climate change will continue to make Canada's forests a tinderbox. And although the best way to safeguard public health is to reduce carbon dioxide emissions, especially from the burning of fossil fuels, researchers at Carleton University have embarked on several projects to help alleviate the impacts of wildfire smoke.
How Wildfire Smoke Moves Through the Atmosphere
Amir Hakami, from Carleton's Department of Civil and Environmental Engineering, specializes in air quality modelling. His research aims to inform policy decisions by providing an assessment framework for climate change mitigation and public health measures.
Outdoor air pollution is one of the leading causes of death and illness around the world and Hakami has been paying increasing attention to wildfire smoke in recent years. But ascertaining how pollutants such as fine particulate matter travel through the atmosphere is challenging.
"Basically, we're trying to estimate the concentration of pollutants that emerge from wildfires," says Hakami, "and better understand how these pollutants move through time and space."
Hakami knows that you can't manage what you can't measure, and that you can't measure everything. His models are an attempt to fill this gap.
"We're hoping to provide information that will allow governments to make efficient and cost-effective decisions that protect people's health," he says.
Hakami and his collaborators are looking into the atmospheric dynamics of prescribed burns, for example. Intentionally setting small, controlled blazes can prevent larger fires from developing, but we don't know if benefits outweigh risks from exposure to smoke in neighbouring areas. Better modelling can help address this question.
He's also co-supervising a group of Carleton students who will be monitoring indoor air quality in several buildings on campus when smoke descends on Ottawa. This project could eventually help engineers design better ventilation systems.
Hakami's work also contributes to broader conversations about climate change solutions. "Health has always been a more potent driver of change," he says, "than strictly environmental concerns."
The Health Impacts of Exposure to Wildfire Smoke
Like Hakami, Carleton epidemiologist Paul Villeneuve, from the Department of Neuroscience and School of Mathematics and Statistics, has become increasingly focused on wildfire smoke.
Villeneuve is in the early stages of a five-year, Canadian Institutes of Health Research-funded project with Sarah Henderson from the BC Centre for Disease Control and others. They're exploring how short-term exposure to wildfire smoke impacts hospitalization and death rates among people 65 and older, in particular those with chronic health conditions.
Carleton University epidemiologist Paul Villeneuve
By overlaying health data from Ontario and B.C. with spatial maps that provide daily measures of wildfire smoke, he'll be able to identify postal codes where people went to the doctor or hospital, and why, as well as upticks in prescription drug use.
"Our research is looking specifically at wildfire smoke and for the first time will come up with risk estimates for those with underlying health conditions for this pollutant," says Villeneuve.
These estimates will inform public messages that can help vulnerable Canadians manage their exposure by doing outdoor activities at certain times of day, for instance, or by wearing a mask.
Villeneuve is also involved with research that's investigating what exactly is in the fine particulate matter conveyed by wildfire smoke. We know the dangers of breathing in particles smaller than 2.5 micrometers in diameter, "but we're starting to look at what's actually on these particles," he says, "as opposed to just counting the particles."
There's growing recognition, Villeneuve says, that Canadian will be dealing with these risks more and more in the years ahead, and that there are both short- and long-term health concerns, from asthma to various cancers, that should be monitored.
"We need to know what the health risks and associated costs are," he says.
"This will help us decide how much we should mitigate exposure to wildfire smoke and what the benefits of doing so are."
