The Hidden Cost of Wildfires: How Smoke Exposure Increases Dementia Risk
Thursday, February 6, 2025.
As wildfires become more frequent and severe due to climate change, a new and alarming consequence is coming to light: exposure to wildfire smoke may significantly increase the risk of dementia.
A recent study published in JAMA Neurology found that folks exposed to wildfire-generated fine particulate matter (PM2.5) faced an 18% higher risk of developing dementia—far greater than the risk posed by other air pollutants (Elser et al., 2024).
This finding raises serious concerns about how environmental factors, particularly air quality, shape long-term brain health.
It also underscores the disproportionate burden of pollution-related health risks on vulnerable communities, making it an urgent issue for public health, environmental justice, and dementia prevention.
Why Wildfire Smoke Is Worse for the Brain
Air pollution has long been linked to cognitive decline, but not all pollutants are created equal.
The tiny particles in PM2.5—measuring less than 2.5 microns across—can infiltrate deep into the lungs and bloodstream, triggering inflammation and oxidative stress that accelerate aging in the brain. However, wildfire-generated PM2.5 appears to be even more dangerous.
The study, led by Holly Elser of the University of Pennsylvania, was freaking huge.
She analyzed 1,223,107 medical records from Kaiser Permanente Southern California, tracking participants aged 60 and older over an 11-year period (Elser et al., 2024).
The researchers found that even a minor increase in wildfire-related PM2.5 (just 1 microgram per cubic meter) led to an 18% jump in dementia risk. By comparison, the same increase in PM2.5 from non-wildfire sources raised dementia risk by just 1%.
What makes wildfire smoke so uniquely harmful?
Scientists believe it contains a more toxic mix of chemicals and ultrafine particles that penetrate the body and brain more easily.
The high levels of combustion-related toxins, heavy metals, and volatile organic compounds in wildfire smoke may accelerate neurodegeneration, contributing to diseases like Alzheimer’s and other forms of dementia (Liu et al., 2023).
The Unequal Burden of Wildfire Smoke Exposure
Not everyone faces the same level of risk.
The study found that folks from racially minoritized backgrounds and low-income communities were disproportionately affected by wildfire pollution.
Factors like poor housing quality, reduced access to air filtration systems, and pre-existing health disparities may all contribute to this increased vulnerability (Elser et al., 2024).
The researchers speculate that systemic inequalities play a role. “Lower-quality housing may increase smoke infiltration, and poorer families may have constrained economic choices that limit their ability to pay for air filtration systems to improve air quality during smoke events,” they note.
Additionally, the chronic stress associated with economic hardship and discrimination may worsen the physiological effects of environmental pollutants, making marginalized populations even more susceptible to dementia (Gee & Payne-Sturges, 2021).
Younger Seniors Face Higher Risk
One surprising finding was that wildfire smoke exposure was more strongly linked to dementia in younger seniors—those under 75 years old.
Researchers suggest that older folks may have already developed dementia-related brain changes before the study began, or that younger seniors were more active outdoors, increasing their exposure to wildfire pollution (Elser et al., 2024).
What Can Be Done?
While wildfires are an escalating threat, there are steps individuals and communities can take to mitigate the risks:
Improve Indoor Air Quality – Investing in high-efficiency particulate air (HEPA) filters can significantly reduce indoor exposure to PM2.5, particularly in regions prone to wildfires (Laumbach et al., 2022).
Reduce Outdoor Exposure During Smoke Events – Seniors and individuals at higher risk should minimize time outside when wildfire smoke is present and wear properly fitted N95 masks if they must go outdoors.
Advocate for Environmental Justice – Policies that improve housing conditions and increase access to air filtration systems in low-income communities could help reduce disparities in wildfire smoke exposure.
Monitor Cognitive Health – Those living in high-smoke exposure areas may benefit from regular cognitive assessments to detect early signs of dementia and intervene with lifestyle changes that support brain health (Livingston et al., 2020).
The Bigger Picture: Climate Change and Brain Health
This study highlights yet another reason why addressing climate change isn’t just an environmental necessity—it’s a public health imperative.
With wildfires growing more frequent and severe, proactive policies to reduce pollution exposure and mitigate health risks will be critical for protecting aging populations from dementia.
As our understanding of the relationship between air pollution and neurodegeneration deepens, one thing is clear: the quality of the air we breathe today is shaping the health of our brains tomorrow.
Be Well, Stay Kind, and Godspeed.
REFERENCES:
Elser, H., Frankland, T. B., Chen, C., Tartof, S. Y., Mayeda, E. R., Lee, G. S., Northrop, A. J., Torres, J. M., Benmarhnia, T., & Casey, J. A. (2024). Wildfire smoke exposure and incident dementia. JAMA Neurology.https://doi.org/10.xxxx/jamaneurology.xxxxx
Gee, G. C., & Payne-Sturges, D. C. (2021). Environmental health disparities: A framework integrating psychosocial and environmental concepts. Environmental Health Perspectives, 129(4), 45002. https://doi.org/10.xxxx/ehp.xxxx
Laumbach, R. J., Meng, Q., & Kipen, H. M. (2022). What can individuals do to reduce personal health risks from air pollution? Journal of Allergy and Clinical Immunology, 150(2), 390-398. https://doi.org/10.xxxx/jaci.xxxx
Liu, N. M., Miyashita, L., Maher, B. A., McPhail, G., & Jones, C. J. (2023). Air pollution and neurodegenerative diseases: A systematic review. Environmental Research, 218, 114512. https://doi.org/10.xxxx/envres.xxxx
Livingston, G., Huntley, J., Sommerlad, A., Ames, D., Ballard, C., Banerjee, S., ... & Mukadam, N. (2020). Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet, 396(10248), 413-446.