PHO Rounds: 2023 Wildfire Smoke Exposure and Public Health in Ontario: Triangulation of Evidence

During the 2023 wildfire season, millions of people in Canada and the U.S. experienced unprecedented exposure to wildfire smoke originating from South Central Canada, encompassing Ontario and Quebec. This exposure was notably pronounced during the large fires that erupted in early June (referred to as the wildfire event). While the health impact of this event was assessed in certain U.S. regions, the impact on Ontario's population remains unknown. Furthermore, there is limited understanding of the specific health effects resulting from this wildfire smoke exposure. To address these gaps, we leveraged this wildfire event as a natural experiment to quantify the effect of wildfire smoke exposure on selected respiratory and cardiovascular outcomes across Ontario’s 22 largest health regions (~80% of total population) and will present the results in this PHO Rounds. Health data for this period were collected from two complementary sources: the Acute Care Enhanced Surveillance Application (ACES) in Ontario for real-time syndromes of public health concern and the Canadian Institute for Health Information’s National Ambulatory Care Reporting System (NACRS) for emergency department visits. Triangulating evidence from both data sources and multiple epidemiological methodologies, our analysis revealed that the wildfire event was responsible with heightened adverse effects in Ontario, particularly impacting respiratory outcomes, with effects persisting for up to five days.

By the end of this session, participants will be able to:

• Discuss the acute impact of wildfire smoke exposure on human health, especially among Ontarians
• Describe new findings and gaps in the area of wildfire-related health research
• Describe the principles and the emerging methodologies in triangulating evidence in health research

Presenter(s): Hong Chen