THE Scientists at McGill University found that ultrafine particles are mainly found in emissions from vehicles and industrial activities.

According to lead researcher Scott Weichenthal, these particles’ small size makes them easier to enter the lungs and bloodstream, which can pose a significant risk to human health.

Long-term exposure to these particles increases the risk of non-accidental death by 7.3%, the study says. In fact, we are seeing an increasing number of deaths related to respiratory diseases, followed by deaths from coronary heart disease.

Mr Weichenthal also stresses that the size of the particles is important for assessing their health consequences.

“In previous studies that did not take particle size into account, scientists may have overlooked or underestimated the significant health risks,” said he, who is also an associate professor in the Department of Epidemiology, Biostatistics and Occupational Health at McGill University.

The conclusions of this study are based on air pollution levels measured between 2001 and 2016 in Montreal and Toronto neighbourhoods with a total population of 1.5 million adults. Using ground-level measurements, land-use data and aerial photographs, the researchers were able to estimate how many ultrafine particles were in the air at different times. They then used statistical methods to establish a link between exposure levels and risk of death.

More regulation required

With this study, scientists want to raise the alarm. Although air pollution in North America is decreasing, ultrafine particles are still being released into the air despite current environmental regulations, they say. They are therefore calling for more measures to counteract the health risks of ultrafine particles.

“Our work underscores the urgency of taking regulatory action against these particles,” explained researcher Weichenthal. “To ensure the health and well-being of urban residents, it is increasingly important to combat air pollution.”

Supported by the United States Institute for Health EffectsThis study was conducted in collaboration with the University of Toronto, Carleton University, the University of Ottawa, Health Canada and Statistics Canada. The results were published inAmerican Journal of Respiratory and Critical Care Medicine.