Last summer was a banner season for poor air quality in Toronto, but the temporary smoke from what ended up being the nation's worst wildfires on record has nothing on the more nefarious — and worse than we thought — contaminants that we are breathing in year-round.

Fifteen years worth of research out of McGill University that was just published this week has concluded that ultrafine particles (UFPs) present in the air of cities like Toronto and Montreal are behind 1,100 premature deaths per year, and that more regulations for this specific type of pollutant are desperately needed.

According to the study, released Monday, UFPs are capable of entering our bloodstream upon inhalation due to their small size, and "may contribute to heart and lung diseases, as well as certain forms of cancer."

Over the timespan, researchers noted a 17.4 per cent spike in respiratory deaths correlated with UFPs, along with a 9.4 per cent uptick in coronary artery disease and a 7.3 per cent increase in the risk of non-accidental death.

Study points to an urgent public-health need for tighter environmental regulations

Conducted in Montreal and Toronto and led by #McGill researchers, study links about 1,100 premature deaths per year to an unregulated air pollutant.https://t.co/1A6XnIWUvB #Pollution

— McGill University (@mcgillu) August 5, 2024

For whatever reason, the serious health effects of long-term exposure to these particles has not been studied in such a way in Canada until now, with the paper stating that "previous studies that did not take particle size into account might have missed or underestimated the serious health risks associated with them."

The same authors stated in previous work on the subject that "few studies have evaluated these relationships," leading to this in-depth investigation.

The body of research spans from 2001 to 2016, and covers large swaths of both cities home to millions of people, using ground-level measurements aerial images, land use information and more. 

"Our research shows a clear link between long-term UFP exposures and increased mortality risk, underscoring the urgent need for regulatory actions targeting these particles," the article states.

"As urban areas continue to grow, addressing air pollution is increasingly crucial for the health and well-being of city dwellers."