This study assessed personal exposures to traffic-related air pollution (TRAP) among bus transit users in Toronto, Ottawa, and Vancouver, Canada. Bus commuting (4.6% of the day) contributed significantly to daily PM2.5 exposures (57-60%), particularly for barium and iron. Enclosed bus stations were identified as PM2.5 and black carbon hotspots. Buses with diesel particulate filters (DPFs) and hybrid diesel/electric propulsion showed significantly lower in-bus PM2.5, ultrafine particles (UFPs), and black carbon compared to older diesel buses. These findings highlight the contribution of bus commuting to daily TRAP exposure and suggest that newer bus technologies improve air quality for riders.

Keith Van Ryswyk, Greg J. Evans, Ryan Kulka, Liu Sun, Kelly Sabaliauskas, Mathieu Rouleau, Angelos T. Anastasopolos, Lance Wallace, Scott Weichenthal