As climate change intensifies, Canadians are increasingly being forced to cope with the combined threat of extreme heat and wildfire smoke two environmental hazards that not only overlap during the hottest months of the year, but also amplify each other’s impacts on health. From the devastating 2023 wildfire season to the deadly 2021 heat dome, recent events have shown that these climate risks are no longer isolated. Now, they’re occurring together more frequently, more intensely, and with serious health consequences.
More Than Just Smoke or Heat: The Rising Danger of Combined Exposure
While there’s robust scientific evidence linking wildfire smoke to hospitalizations for lung and heart conditions and heat waves to deadly strokes and cardiovascular stress most research has looked at these hazards in isolation. Yet in reality, people are rarely exposed to just one threat at a time. With wildfire seasons now peaking during the warmest months of the year, simultaneous exposure is becoming more common, and early studies show this “climate double whammy” may actually worsen respiratory, cardiovascular, and birth outcomes.
Tracking the Overlap: 13 Years of Data Reveal a Stark Pattern in British Columbia
To understand how widespread and frequent these overlapping threats have become, researchers at the British Columbia Centre for Disease Control examined 13 years of temperature and air quality data across more than 400 communities in the province. Their findings are sobering:
- All communities studied experienced at least 7 days of co-occurring wildfire smoke and extreme heat from 2010 to 2022.
- Some areas saw as many as 65 days of concurrent exposure.
- The frequency of these dual hazard days has increased significantly over time. From 2010–2014, communities averaged just 1 such day per year; by 2018–2022, the number had jumped to 4.5 days annually.
Rural and Vulnerable Communities Hit Hardest
The northeast and south-central regions of British Columbia emerged as the most impacted. These communities are typically rural or remote, with limited access to resources like healthcare, clean indoor air, and cooling facilities. They also tend to have lower socioeconomic status and a higher proportion of at-risk populations, including seniors making them especially vulnerable to the combined effects of heat and smoke.
Public Health Messaging Falls Short
Despite the growing threat, Canada’s public health response has not kept pace. A review of national and provincial guidance found that instructions for dealing with simultaneous exposure to smoke and heat were incomplete and inconsistent. For example:
- Cooling centres open during heat waves may lack proper air filtration, exposing vulnerable residents to wildfire smoke.
- Clean air shelters set up during smoke events may lack air conditioning, compounding heat-related risks.
- This fragmented approach leaves communities confused and unprepared for the realities of today’s compound climate events.
Canada Must Adapt: Dual-Hazard Strategies Needed
To protect public health, particularly in remote and disadvantaged areas, Canada must develop integrated adaptation strategies that:
- Acknowledge the overlap between wildfire smoke and extreme heat
- Tailor responses to the specific risks and needs of each community
- Ensure public health messaging is clear, consistent, and actionable
- Equip shelters and public spaces to handle both smoke and heat simultaneously
Investing in combined hazard solutions such as clean, air-conditioned shelters, better early warning systems, and community-specific outreach could save lives and ease the burden on healthcare systems.
The Path Forward: Building Resilience for Hotter, Smokier Summers
As climate extremes become the new normal Canadians especially those in rural and vulnerable regions will need better protection from multiple, overlapping climate hazards. The research makes it clear: single-hazard solutions are no longer enough.
To reduce health risks and save lives, adaptation efforts must evolve with the climate. Preparing for hotter and smokier summers isn’t just wise it’s urgent.