McGill University models how EV adoption, retiring older diesel trucks and reducing traffic could lower exposure to ultrafine particles.

Canadian cities are rife with ultrafine particles (UFPs) from vehicle emissions, but a shift to cleaner transportation and lower traffic levels could avert more than 3,600 premature deaths by 2040, a new study found.

Researchers from McGill University studied how these microscopic pollutants can affect residents of Toronto and Montreal, and modelled how various policies would change UFP levels. 

The study found that thousands of premature deaths could be prevented with a three-pronged strategy: rapidly adopting electric vehicles, retiring older, heavy-duty vehicles (particularly pre‑2007 diesel trucks), and lowering overall traffic levels.

Elevated concentrations

Marshall Lloyd, a study author and research associate at McGill in the Department of Epidemiology, Biostatistics, and Occupational Health, said in an interview with Electric Autonomy Canada, “In our research, we’ve seen there’s elevated concentrations of these ultrafine particles in the city, compared to other parts of the country, and these UFPs are harmful for our health. By focusing on a few strategies [there are] health gains that can be made by reducing UFP emissions.”

Discussing the harmful effects of UFPs, he pointed to several studies underscoring how these particles degrade the human body. A 2023 analysis by researchers at Fudan University in Shanghai found that “UFPs exposure may not only induce DNA damage but also affect the repair of DNA defects.”

Alternate study

Lloyd noted that another study by his McGill team in 2024 linked UFPs to 1,100 premature deaths per year. That would mean that by 2040, there would be at least 17,600 premature deaths attributable to UFPs.

He addressed this discrepancy by pointing out that the current study looks at the cumulative death toll from 2021 to 2040, and tracks not all the people who die from exposure to UFPs, but how many premature deaths could be avoided if the amount of air pollution were reduced gradually.

He said the 2024 study approached the modelling as if air pollution had been reduced to zero, as opposed to a gradual reduction.

Multiple strategies

Lloyd shared another statistic from his department’s research: being exposed to UFPs could increase the risk of mortality by 7.3 per cent. 

On replacing high-emission vehicles with electrified fleets, Lloyd said, “An EV is nice, because there’s zero tailpipe emissions, but that’s just one approach, and we need to include other strategies, such as reducing traffic and improving emission standards.”

Next for Lloyd are two studies building on his team’s past two reports: one study will expand the Montreal-Toronto findings to a cross-Canada investigation, and a second study will focus on the short-term effects of being exposed to a high concentration of UFPs.