The Surprising Connection Between Wildfire Smoke and Brain Health: What You Need to Know
Wildfires are getting worse. Look at what has happened in California, Greece, in Portugal. Of course, with global warming, you can be sure that there will be more devastating wildfires. Wildfires are not only ravaging the environment and endangering communities, but their smoke has a hidden cost: brain health. Beyond the obvious risks to the lungs and heart, emerging research shows that wildfire smoke increases the likelihood of developing dementia, reduces cognitive function, and exacerbates neurological conditions.

Read on to understand how wildfire smoke impacts your health and how to protect yourself from smoke. We’ll cover what wildfire smoke contains, how it may harm the brain, and what you can do to stay safe.
Wildfire Smoke: The Unseen Hazard in the Air
Wildfire smoke is no ordinary pollution. It’s a mixture of harmful substances like gases, chemicals, and fine particulate matter, also called PM2.5. PM is short for particulate matter. The 2.5 refers to tiny particles less than 2.5 microns in diameter—roughly 30 times smaller than the width of a human hair. These particles are so small that they can bypass the body’s natural defences, travelling deep into the lungs, entering the bloodstream, and even reaching the brain.
Research suggests that wildfire-related PM2.5 may be more toxic than the particles typically emitted from vehicles or factories. In fact, studies show that PM2.5 from wildfires causes higher rates of death and more severe health effects than other types of air pollution.
The Alarming Growth of Wildfire Smoke Exposure
Although the number of wildfires hasn’t increased in recent years, their intensity, size, and duration have surged due to climate change. Warmer temperatures, earlier snowmelt, and prolonged droughts have made forests more flammable and fire seasons longer. Ill-considered policies that suppress natural fires have also contributed to an over-accumulation of fuel, making fires harder to control.
This has led to unprecedented levels of wildfire smoke exposure across the United States and beyond. For example, in 2023, Americans were exposed to more wildfire smoke than in any year since 2006. Such widespread pollution not only impacts air quality in affected areas but can travel thousands of miles, posing health risks to far-off communities.
How Wildfire Smoke Affects Brain Health
Increased Dementia Risk
One major concern is the link between wildfire smoke and dementia. A groundbreaking study published in JAMA Neurology analysed data from over 1.2 million older adults and found that every 1 µg/m³ increase in wildfire-related PM2.5 raised the odds of developing dementia by 18%. In contrast, PM2.5 from non-wildfire sources increased dementia risk by just 1%.
Why such a significant difference? Wildfire smoke often creates “smoke waves,” short periods of highly concentrated pollution. Researchers believe these intense bursts could overwhelm the body’s defenses, triggering damaging inflammation in the brain.
Cognitive Performance and Everyday Focus
You don’t have to wait years to feel the effects. Studies show wildfire smoke impacts the brain within hours. For instance, adults playing the Lumosity brain game “Lost in Migration” experienced a dramatic dip in performance—losing up to 117 points—after heavy wildfire smoke exposure.
Children are particularly vulnerable, too. Research published in Nature Sustainability linked wildfire smoke exposure to decreased test scores among students aged 8 to 14, underscoring the educational and cognitive impacts of these pollutants.
Links to Neurological Disorders
Wildfire smoke doesn’t stop at dementia and cognitive focus. Evidence suggests it could contribute to conditions like:
- ADHD in children: Pollution exposure, especially heavy metals and chemicals in wildfire smoke, has been linked to increased ADHD symptoms.
- Parkinson’s disease (PD): Long-term exposure to PM2.5 raises the risk of developing PD, particularly its more severe subtypes.
- Multiple sclerosis (MS): People living in areas with higher levels of air pollution face a greater risk of developing MS, highlighting a potential environmental trigger.

How Does Wildfire Smoke Harm the Brain?
Researchers are still uncovering the exact mechanisms, but current evidence points to several pathways:
- Crossing the Blood-Brain Barrier
PM2.5 particles can travel from the lungs to the brain, bypassing the blood-brain barrier—a protective shield that keeps harmful substances out. Once there, these particles can interact with brain tissue directly. - Neuroinflammation
Studies on mice show that wildfire smoke causes inflammation in the hippocampus, the brain’s center for learning and memory. This inflammation may persist for weeks, disrupting brain function. - Oxidative Stress
Wildfire smoke generates free radicals, unstable molecules that can damage cells. In the brain, oxidative stress contributes to cognitive decline and neurological disorders. - Combined Effects with Heat
When wildfire smoke coincides with extreme heat, as often happens during fire season, the combined stressors can amplify the harm to the brain.
Protecting Yourself from Wildfire Smoke
The good news is you can take proactive steps to reduce your risk:
- Monitor Air Quality: Use tools like the Air Quality Index (AQI) to track pollution levels in your area.
- AQI 0–50: Good
- AQI 51–100: Moderate
- AQI >100: Unhealthy—take precautions!
- Stay Indoors: Limit outdoor activities when wildfire smoke is present. Keep doors and windows closed.
- Run Air Filters: Invest in HEPA filters to clean the air in your home.
- Wear Protective Masks: Use an N95 or KN95 mask outdoors during smoke events to filter out PM2.5 particles.
Final Thoughts
Wildfires are a growing reality of climate change, but their smoke carries risks far beyond what’s visible. By understanding how wildfire smoke impacts the brain—and taking steps to minimize exposure—you can protect your cognitive health and that of your loved ones.
Your brain is your most vital asset. Don’t let wildfire smoke cloud its potential. Stay informed, stay safe, and take action to preserve your well-being.