Emissions and atmospheric pollution concentrations in Quebec and Canada have generally declined since the early 2000s. However, fine particulate matter has decreased less than other pollutants, and the recent rise in wildfires raises concerns about a resurgence, with negative impacts particularly on young people.

In this study, the authors assess the effects of ambient fine particulate matter concentrations on the cognitive and behavioral development of Canadian children aged 4 and 5. Although scores on certain tests are negatively associated with exposure to fine particulate matter, these associations remain modest and statistically difficult to detect.