Environmental Epidemiology • Vol 9 • No 5
Within-city spatiotemporal variations in outdoor ultrafine particles and emergency room visits for cardiovascular outcomes
September 2025 • Scott Weichenthal, Éric Lavigne, Marshall Lloyd, Alessya Venuta, Arman Ganji, Junshi Xu, Milad Saeedi, Shoma Yamanouchi, Ryan Kulka, Marianne Hatzopo…
Background: Few epidemiological studies have examined the acute cardiovascular health impacts of within-city spatiotemporal variations in outdoor ultrafine particles (UFPs). Methods: We conducted a time-stratified case-crossover study of within-city spatiotemporal variations in outdoor UFPs and emergency room visits for cardiovascular outcomes in Toronto, Canada, between 2019 and 2020. Outdoor UFP data (lag-0, 3-day mean, and 7-day mean) were assigned to residential locations using exposure models trained using da…