Smoke from wildfires, a major source of air pollution, has been linked to serious health issues including heart attacks, strokes and lung diseases such as asthma.
Fire season brings other health risks as well. When the sky darkens with smoke and communities face possible evacuation and destruction, it can have a profound effect on a person’s mental state.
What contributes to this feeling of stress during smoking season – or “fire brain“as it is sometimes called? Chronic and persistent smoking episodes are a relatively new phenomenon, and research into their effects on mental health is still in its infancy.
Yet research is beginning to make connections that can help us better understand how these complex interactions affect our well-being, and help us identify potential solutions.
What effect does wildfire smoke have on the brain?
Air pollution affects our brain health and cognitive function. Researchers have found that fine particulate matter (PM2.5) pollution released by wildfires can even more poisonous than air pollution from other sources. One possible reason is the high level of polycyclic aromatic hydrocarbons (PAHs) mixed with varying levels of other known neurotoxic particles found in smoke, including heavy metals. These particles can reach the brain via the olfactory nerve and cross the blood-brain barrier, or modulate the nervous system, leading to encephalitis and oxidative stress.
Can wildfire smoke affect cognitive ability?
Neuroinflammation caused by wildfire smoke increases risk of development Alzheimer’s, dementia and Parkinson’s disease. Recent research from the universities of Washington and Pennsylvania found that the risk of a new diagnosis of dementia increases by about 21% for every 1 microgram increase in the concentration of wildfire particles a person inhales, compared to a 3% increased risk for every 3 microgram increase in non-wildfire particles.
Additional research from the University of New Mexico suggests that sudden increases in air pollution, such as those that occur during wildfires, trigger waves of inflammation in the hippocampus region of the brain responsible for memory and learning. These can last longer than a month after exposure.
That could explain why, in addition to several studies that found a link between smoke exposure and poorer concentration and decision-making skills during gaming, digital games And sport-Smoky days also appear to be associated with poorer school performance.
In a 2020 study, University of San Diego economist and researcher Josh Graff Zivin found investigated how smoky air affected students taking the national college entrance exam in China over a six-year period. Graff Zivin specifically studied smoke created by routine, controlled agricultural fires, removing potential fears about possible evacuations as a factor from the study.
His team found that when there was a significant increase in fires upwind compared to downwind during the exam, students’ total scores dropped by an average of 0.6 points. This drop in scores also slightly reduced students’ chances of getting into top universities. A U.S. study By 2022, it is estimated that smoke exposure in 2016 reduced students’ future earnings by nearly $1.7 billion (or $111 per student).
“We don’t know exactly what happens to the brain” during high-smoke days, Graff Zivin says. “But we know it’s bad.”
The cardiovascular effects of smoke inhalation can affect our body’s ability to properly oxygenate our brain. “Likewise, reduced lung function alone can lead to cognitive impairment,” he says.
But more research is needed to fully understand how smoky days affect cognitive performance, and we don’t yet fully understand the cumulative impact of smoke exposure over weeks or months of the year, Graff Zivin adds.
What is the connection between smoky days and depression?
It is not entirely clear how smoking may physiologically affect the brain in ways that contribute to feelings of depression, but researchers believe Cognitive impairments – such as those Graff Zivin observed in students taking tests – may be a factor in depressed mood. Researchers also increasingly believe Brain inflammation plays a role in the development of depressionwhich creates the possibility that brain inflammation caused by smoke from wildfires may contribute to mood disorders.
The stress and trauma of a wildfire can also affect mental health, psychiatrist Dr. Jyoti Mishra of the UC San Diego School of Medicine studied people who were directly and indirectly exposed to the 2018 Camp Fire, a year after it tore through Butte County, California. Perhaps unsurprisingly, she found that those who experienced significant personal loss or trauma during the fires showed the highest levels of PTSD, anxiety, and depression. Yet even community members who were not directly affected by the fires reported increased neurocognitive problems and struggled with depression and anxiety.
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Some of the fears people living near wildfires experience have to do with “seeing changing landscapes, changing environments, and being concerned about both the present and the future,” says Dr. Warren Dodd, an associate professor in the University of Waterloo’s School of Public Health Sciences.
Dodd has interviewed residents of Canada’s Northwest Territories who experienced a record fire season in 2014 reported feelings of anger, stress and hopelessness about the threats posed by climate change.
In addition to the stress of seeing your environment change rapidly (also known as solastalgia), the people Dodd interviewed said that giving up their summer outdoor and land activities to stay indoors had negative effects on their mental health.
What can we do about the mental health effects of bushfires?
To reduce the physiological effects of wildfire smoke on our brains, we need to take many of the same steps we take to protect the rest of our bodies from air pollution. For example, we should use air purifiers at home, thoroughly clean living spaces to remove particulate matter that comes inside, wear masks outside, and limit unnecessary time spent outdoors.
When it comes to limiting the psychological damage of smoky days, local authorities can step in. Making community resources available for free during wildfires is one way to help people relieve some of the isolation and anxiety they feel as they shelter indoors. For example, Dodd notes, the City of Yellowknife waived the fee for its indoor recreation center during the fire, allowing people to get some exercise and see their neighbors without having to go outside.
Resilience is important for communities to focus on, Mishra says—not just after a climate disaster, but also preventatively. “When we studied the people at Camp Fire, we found that there are certainly some characteristics, like being more mindful and more physically active, that can contribute to a sense of resilience,” she says. But what mattered most was the strength of people’s families and social connections.
People who “feel supported and feel like there’s a sense of community around you are the most protected in terms of their mental health outcomes,” she says. A stronger sense of community can be an antidote to loneliness and a tool for climate resilience, Mishra notes. For people experiencing PTSD, therapy for underlying neurocognitive issues can aid in recovery.
As always, prevention is key: by reducing greenhouse gas emissions, we can slow global warming and help limit wildfires and their devastating, complex consequences.
Graff Zivin believes that governments need to consider the economic impact of reduced productivity and cognitive function, and invest more in forest fire prevention and forest health. A healthy forest maintained with prescribed fires can lead to less intense forest fires, he says. “We rarely talk about the value of healthy forests.”