Wildfire Smoke Isn’t Just Hard on Your Lungs. Your brain is at risk too.

When thick wildfire smoke blankets Calgary, many people stay indoors because they know it can make breathing difficult. But according to University of Calgary physician Dr. Bhavini Gohel, the dangers don’t stop at the lungs.

Researchers are now discovering that wildfire smoke may also affect the brain particularly for older adults and people living with dementia.
“The smoke is not benign,” says Dr. Gohel, a clinical assistant professor at the University of Calgary, founder and chair of the Brain Climate Equity Collaborative, and medical lead for the Climate Health System Alliance at the O’Brien Institute for Public Health. “It’s very dangerous, and many people don’t realize just how dangerous it can be.”

Why are older adults at greater risk?

Wildfire smoke contains tiny particles known as PM2.5 fine particulate matter that is small enough to be inhaled deep into the lungs. Even more concerning, these microscopic particles can enter the bloodstream and may even reach the brain through the nose. Once inside the body, the particles trigger a stress response that produces harmful molecules, leading to inflammation and cellular damage.

For older adults, that inflammation can have an even greater impact.
“As we age, our brains become more vulnerable,” Dr. Gohel explains. “Many older adults already have some degree of cognitive decline, whether it’s mild memory changes or dementia. When you add inflammation caused by wildfire smoke, it makes the brain much more susceptible to injury.”

The link between wildfire smoke and dementia

Scientists are only beginning to understand how wildfire smoke affects the brain, but the evidence is growing. Research has already shown that air pollution is an important risk factor for Alzheimer’s disease and other forms of dementia. Dr. Gohel says repeated exposure to wildfire smoke may increase that risk over time.

“It’s an added risk factor,” she says. “If someone is already at risk of developing Alzheimer’s disease and they’re repeatedly exposed to wildfire smoke, we believe it’s likely to increase that risk.”
She emphasizes that while some of the short-term inflammation settles once smoke exposure ends, repeated exposure year after year may contribute to lasting damage. “It’s similar to smoking cigarettes,” she explains. “You can’t reverse the initial damage, but you can prevent it from getting worse by reducing future exposure.”

More than memory problems

Even healthy people may notice the effects of wildfire smoke.
Many report headaches, difficulty concentrating, fatigue and what people often describe as “brain fog.” “I notice it myself,” says Dr. Gohel. “When the air quality is poor, I find I’m a little more foggy and my attention isn’t as good.”

For someone already living with dementia, those symptoms can become much more severe. “If a person with dementia suddenly becomes much more confused or their memory is significantly worse than their normal baseline during a smoke event, that’s something that should be medically assessed,” she says.

Recent Canadian research has also linked wildfire smoke to increased emergency department visits for migraines, while scientists continue to investigate possible connections with mental health conditions, cancer and other neurological diseases.

Protecting your lungs and your brain

The good news is that there are effective ways to reduce your exposure.
Dr. Gohel recommends:

• Stay indoors whenever air quality is poor.
• Keep windows and doors closed.
• Use an N95 respirator if you need to be outside. Unlike cloth masks, N95 masks filter out about 95 per cent of fine particles.
• Upgrade your home’s furnace filter to MERV-13, or at minimum MERV-11, to remove more smoke particles from indoor air.
• Avoid creating additional indoor pollution, such as burning candles or smoking.

People living with asthma or chronic obstructive pulmonary disease (COPD) should pay particular attention to worsening symptoms.
“If you’re needing your inhaler more frequently or you’re having trouble breathing, seek medical attention right away,” she says.

What about long-term care homes?

Dr. Gohel believes long-term care and continuing care facilities also need to prepare for increasingly smoky summers. Although many facilities have modern ventilation systems, smoke particles can still enter buildings through doors and windows. She says facilities should ensure they have high-quality HVAC filtration systems and provide residents with access to N95 masks whenever outdoor exposure is unavoidable.

A new reality

When Dr. Gohel first moved to Canada, smoky summers were uncommon. Today, they have become an expected part of life.
“This is becoming an annual event,” she says. “Canada is warming quickly, our forests are becoming drier, and we’re seeing more wildfire smoke every year.” She would like to see stronger public health messaging, including cellphone alerts warning people when air quality reaches dangerous levels and clear guidance on how to stay safe. She also believes healthcare providers should receive advance notice so hospitals are prepared for increases in emergency visits during severe smoke events.

For older adults, the message is simple.

Prepare before smoke season begins. Keep N95 masks on hand, ensure your home’s filtration system is working properly, and take air quality warnings seriously. “Everyone is affected by wildfire smoke,” says Dr. Gohel. “But older adults are especially vulnerable. Protecting yourself today may help protect your brain and your lungs for years to come.”