When Environment and Climate Change Canada (ECCC) urged Montrealers to limit outdoor activity during Canada’s worst wildfire smoke episodes, the city’s travel patterns shifted – but far less than public health officials might have hoped, according to a new McGill University study.
Researchers at the University’s Platial Analysis Lab examined how Montrealers were moving during 27 days, in 2022 through 2025, when smoke-related air quality advisories were in effect. They found that, on those days, bikeshare (BIXI) trips fell by 5.8 per cent, while bus ridership rose by 6.7 per and metro ridership rose by 4.7 per cent.
“While people moved from open-air travel into enclosed modes, which is what the bulletins ask for, the size of the change was small,” said study co-author Daniel Romm , a PhD candidate in the Department of Geography.
Recreational running – the activity that health bulletins caution against most directly – showed no statistically significant change at all, the researchers said. They measured this using data from the Strava running app, though they caution that limitations of the dataset may have affected the result.
“There are severe health risks from exposure to wildfire smoke, and, as wildfires increase in frequency , their smoke is among the more costly and dangerous risks of the changing climate,” said Romm. “More needs to be done to communicate the dangers of smoke exposure, especially as the future probably holds many more smoky seasons in Montreal and across Canadian cities.”
The researchers found the steepest declines in bikeshare use were not downtown, but in outlying boroughs.
Metro stations told a similar story in reverse: Most stations gained riders on advisory days, but Place-d’Armes in the downtown core lost 6.2 per cent of its traffic, while Université-de-Montréal gained 24.8 per cent.
The researchers suggest this could be because students and staff who would normally cycle to campus switched to public transit, with some downtown trips being skipped altogether.
The team drew on daily trip counts from four sources of movement data, while records of air quality bulletins were provided by ECCC.
Rather than compare advisory and no-advisory days, the team built a forecasting model for each travel mode that predicted how much travel would have occurred on a given date had no advisory been issued. The model accounted for weather, day of the week, season, holidays and major public events. They used the gap between their predictions and what actually happened to estimate the advisories’ effects.
Romm said the findings present an opportunity to develop practical strategies.
“Advisories may need to be paired with practical measures that make compliance easier, such as temporarily reduced transit fares during smoke episodes, or employer support for remote work.”
The team plans to conduct similar analyses in other cities and compare results.
“ Urban Mobility Responses to Wildfire Smoke-Related Air Quality Advisories in Montréal, Canada ,” by Daniel Romm, Priyanka Verma, Dan Qiang, Farzaneh Sadeghi, Jenny Zhu, Mackenzie Johnston and Grant McKenzie, was published in Health & Place.
This research made use of data provided by Environment and Climate Change Canada, the Société de transport de Montréal, BIXI and the Montréal Air Quality Monitoring Network.
Health & Place
10.1016/j.healthplace.2026.103736
Data/statistical analysis
Not applicable
Urban mobility responses to wildfire smoke-related air quality advisories in Montréal, Canada
12-Sep-2026