I arrived in Williams Lake during what locals call “the aftermath.” Three months after the region’s largest wildfire had been contained, the physical flames were gone, but their presence lingered like a ghost. Driving through neighborhoods where evacuation orders had only recently lifted, I noticed how residents unconsciously touched their throats when speaking about that summer.
“I’ve never been a smoker, but I feel like I’ve picked up a pack-a-day habit,” said Marion Cheung, a 54-year-old elementary school teacher who has lived in this central British Columbia community for over two decades. “My doctor says my lungs sound different now.”
Marion’s experience isn’t unusual, according to groundbreaking research published last week in the Canadian Medical Association Journal. The multi-year study tracked health outcomes of residents in wildfire-affected communities across British Columbia and Alberta, revealing that harmful health effects from wildfire smoke exposure can persist for six to eight months after the fires have been extinguished.
The research team, led by Dr. Sarah Henderson of the British Columbia Centre for Disease Control, documented a 25% increase in respiratory-related hospital visits in the months following major wildfire events, even after accounting for seasonal illnesses and pre-existing conditions.
“We’ve long understood the immediate dangers of wildfire smoke,” Henderson explained during our conversation at her Vancouver office. “But this data shows we’re dealing with a much longer recovery window than previously thought. The microscopic particles don’t just disappear when the smoke clears.”
The study followed over 9,000 residents from communities that experienced significant wildfire activity between 2017 and 2023, a period that saw some of British Columbia’s most devastating fire seasons on record. What makes this research particularly valuable is its comprehensive approach — tracking not just respiratory issues but cardiovascular problems, mental health impacts, and changes in cognitive function.
For Indigenous communities, the health impacts are compounded by cultural and economic disruptions. In Tŝilhqot’in territory, where wildfires have become increasingly common, Elder Margaret William told me how smoke seasons have disrupted traditional food gathering and medicine harvesting.
“Our berries don’t grow the same in the years after big fires,” William said, running her hands along dried saskatoon branches in her yard. “And when the medicines can’t grow right, we lose more than food — we lose our pharmacy, our classroom, our connection.”
The research confirms what William and other Indigenous knowledge keepers have observed: ecological recovery timelines affect human health recovery. Areas with delayed vegetation regrowth showed longer-lasting health effects among residents, particularly those with pre-existing respiratory conditions.
Dr. Melissa Lem, president of the Canadian Association of Physicians for the Environment, wasn’t surprised by the findings. “We’re seeing a dramatic shift in how we need to approach wildfire seasons from a public health perspective,” she told me via video call from her clinic in Vancouver. “This isn’t just about getting through a few smoky weeks anymore — it’s about long-term community health planning.”
The research team identified several mechanisms behind these prolonged health effects. Fine particulate matter from wildfires can trigger inflammatory responses that continue long after exposure ends. Additionally, the psychological stress of evacuation, property damage, and ongoing air quality concerns appears to weaken immune function in affected populations.
Back in Williams Lake, I visited the local health center where nurse practitioner Devon Hargreaves has been tracking his patients’ recovery. “We’ve had to expand our pulmonary rehabilitation program,” he explained, showing me a newly converted therapy room filled with breathing exercise equipment. “And we’re seeing people who never had asthma before suddenly needing inhalers.”
Perhaps most concerning is the study’s finding that children exposed to severe wildfire seasons showed higher rates of new-onset asthma diagnoses for up to three years following exposure. This suggests that developing lungs may be particularly vulnerable to wildfire smoke’s chemical composition, which differs from urban air pollution.
Environment and Climate Change Canada has responded to these findings by launching a specialized smoke forecasting system that will offer more detailed predictions about particulate composition and concentration. The system aims to help communities better prepare for upcoming fire seasons and develop more targeted health interventions.
Dr. Courtney Howard, an emergency physician in Yellowknife and past president of the Canadian Association of Physicians for the Environment, emphasized that these findings have implications far beyond Canada’s borders.
“As climate change drives more frequent and intense wildfire seasons globally, we need to fundamentally rethink how we support community resilience,” Howard said. “This isn’t just about evacuation plans and N95 masks during active fires — it’s about long-term respiratory care, mental health resources, and climate adaptation.”
For residents like Marion Cheung, the study validates what her body has been telling her all along. When I visited her classroom, she showed me the air purifiers now standard in every room and the modified physical education program designed for days when children’s lungs need extra protection.
“We used to worry about smoke days,” she said, adjusting an air quality monitor on her desk. “Now we worry about smoke years.”
As climate scientists predict increasingly severe fire seasons across North America, this research offers crucial guidance for healthcare systems and communities. The findings suggest that post-wildfire health monitoring should continue for at least 12 months, particularly for vulnerable populations like children, elders, and those with pre-existing conditions.
When I left Williams Lake, the physical scars of the wildfires were healing — new growth was visible on blackened hillsides, and rebuilt homes stood where others had been lost. But the invisible impacts continue to shape daily life in ways both subtle and profound. This emerging understanding of wildfire smoke’s long shadow may help communities better prepare for the challenging seasons ahead — not just through the flames, but through the much longer journey of recovery that follows.
