Will Wildfires Erase Our Air Pollution Health Gains?

The Clean Air Act of 1970 and subsequent emission reduction policies substantially lowered air pollution and improved health across the US. Nationwide, the EPA estimated that PM2.5-related premature deaths alone were reduced by ~230,000 by 2020 and NO2 emissions were decreased by ~62% by 2023, saving tens of thousands more lives. (1,2) 

However, forces are now countering these gains: the current administration’s policies of deregulating fossil fuel emissions and obstructing the renewable energy transition are moving us in the wrong direction. Coupled with a persistent and strong El Nino effect, climate change is worsening wildfire air pollution which is especially concerning.

As we know from the news, wildfires are becoming more frequent and more intense in the US and Canada causing worsening air quality widely in North America. (3)  US wildfire PM2.5 related annual premature death estimates are currently over 40,000 per year and could rise to more than 70,000 by mid century. (4)

While wildfire smoke can vary significantly in composition, particulates are typically dominant - PM10, PM2.5 and ultrafine particles - though other potential contaminants like polyaromatic hydrocarbons (PAHs) and metals increase when human sources also burn.  We already have a large body or research on the health associations of PM2.5 air pollution. It is not surprising that recent research shows similar health consequences regarding wildfire PM2.5 pollution.

Here are some of the recent neurological associations demonstrated for wildfire PM2.5:

• Stroke risk: Two recent studies showed PM2.5 wildfire pollution increases of just 1 µg/m3  increased stroke risk 1% and 1.3%. (5,6)

• Dementia risk: A recent paper was retracted for accounting challenges though a tend toward association of dementia and wildfire risk persisted (Elser 2024). Another recent study showed a positive association with wildfire PM2.5. (7,8)

• Low birth weight (LBW) and prematurity risk (and potentially cognitive dysfunction risk): Multiple studies, including 3 published in the last 6 months, link LBW and prematurity with wildfire PM2.5 exposure during pregnancy. (9-11)  Research including a large recent meta-analysis associate LBW and prematurity to early reduced cognitive function. (12)

• Possible autism link:  Multiple meta analyses show mild associations of ambient PM2.5 during pregnancy with autism. (13-16)  A recent paper associates pregnancy wildfire PM2.5 with autism. (17)

• Possible brain tumor risk: A Canadian cohort study showed a 10% increase in brain tumors associated with wildfire exposure. (18)

More research is needed, but this body of wildfire air pollution evidence along with extensive research linking health consequences to particulates from fossil fuel air pollution in general should inform our patient recommendations. Reducing outdoor exercise and exposure with an AQI over 100, especially for those with cognitive impairment, neurodegenerative disease or a history of stroke would be advised. Temporary relocation, wearing a KN95 with a one-way valve outdoors and running a HEPA air purifier indoors during wildfire exposures should all be considered. The more definitive long term health solution is to reduce fossil fuel emissions by converting to renewable energy sources thereby slowing climate change as a driver of future wildfire smoke.  

Reference Links (References also listed below)

Simple actions you can take to make a difference: 

Opportunity to Email/Call Opposing Fossil Fuel Immunity:   The fossil fuel industry is trying to pass congressional legislation to prevent them from being held financially accountable for their pollution and climate change harm.  You can write an email, or call your Senator/ Representative identifying yourself as a physician. See this Medpage Today Opinion piece for more detail.

Opportunity to sign-on to MSCCH Letter urging the ACGME to incorporate climate and planetary health into common and specialty-specific Program Requirements: Support our trainee's by signing on here as an individual and/or organization by June 30.

See Yale Climate Change Communication Reports: 
Climate Change in the American Mind, Fall 2025          Climate Opinion Maps 2025 (May 2026)                        More than 50% of people in every state are at least somewhat concerned about global warming.

Need some good news stories on climate for a change? Check out the The Daily Climate

Feeling Like you need a boost to participate?        Consider joining the MSCCH, or it's local affiliates in your state or other organizations to engage in advocacy with colleagues and community.

See Our Advocacy Page                                               See Our Quick Advocacy Links Table below 

Recent Climate Neurology Publications

Luglio DG. Prenatal Exposure to Wildfire and Autism in Children. [Environmental Science & Technology 2026] adds to the potential low level link of air pollution and autism from previous meta-analyses(13-16)

Saad A, et al.  Stroke and Climate Change: A World Stroke Organization Scientific Statement. [Int J Stroke 2026 Mar]            Our own Ali Saad was the lead on this important first scientific statement from an international stroke organization. 

Two conflicting studies on Motor Neuron Disease:                 Wu J. Long-Term Exposure to Air Pollution and Risk and Prognosis of Motor Neuron Disease. [JAMA Neurology 2026] Long-term air pollution exposure in Sweden was associated with an increased risk of MND and with faster functional decline, particularly motor and respiratory functions, after MND diagnosis.    Chalitsios C. Long-Term Exposure to Ambient Air Pollution and Incident Amyotrophic Lateral Sclerosis [Neurology 2026] study from UK found no association between ALS (n=687) and multiple air pollutants.                                                                 A previous study, by Pedde 2025 found faster decline associated with pollutants, but only with black carbon and nitrate. (19)        More study is needed to clarify the potential association. 

Only one of these two 2026 studies supports previous evidence linking PM2.5 with Parkinson's disease:                        Cole-Hunter T. Long-Term Exposure to Air Pollution and Incidence of Parkinson's Disease: A Danish Nationwide Administrative Cohort Study. [Mov Disord 2026] Positive association with PM2.5, NO2. Danish study. 2000-18     Jahanshahi B. Exposure to ambient air pollution and onset of Parkinson’s disease in a large cohort study. [NPJ 10/2025] Negative-but, a shorter term exposure in Northern Ireland from 2009–2016

Davydow D. Exposure to Air Pollutants and Lewy Body and Parkinson Disease–Related Dementias. [JAMA Netw. Open 2026] Danish study linked increased PM2.5 and NO2 with increased risk of DLB> PDD

Hao H. Long-term exposure to wildfire smoke particulate matter and incident stroke: a US nationwide study [European Heart Journal 2026]  Large Medicare study found that per 1 µg/m3 increase in 3-year average wildfire smoke PM2.5 was associated with a 1.3% increase in stroke risk

Faherty T. Reframing air pollution as a cognitive and socioeconomic risk. [npj clean air 2026]

Madewell E. Preparing Future Physicians: Addressing the Impact of Climate Change on Neurologic Health. [Neurology 2026] Describes a lecture designed to educate medical students on the relevance of climate change to the field of neurology

Our Last Quarter Activities:                                             (links underlined)

• Climate Health and Brain Health, Stanford University Neurology, 12/5/25 (Larry and Bret) Recording, Slides,  Stanford Advocacy Links                          

• Impacts of Climate Change and Air Pollution on Neuropediatric Health, a Scoping Review,  NICHe Winter Meeting, 01/6/26 (Kirsten Sjonnesen MD FRCPC)

• Neurology and Climate,  St Luke's/ ICCH 01/07/26  (Beth and Bret)

• Neurologic Impacts of a Changing World: What We Know and What We Can Do, UCLA Neurology  02/25/26 (Beth and Bret)

• Channeling Outrage into Grace Under Pressure, Substack 02/19/26 (Beth)             

• Climate Change and Brain Health: What We Know and What We Can Do, Mass General Neurology  03/25/26 (Beth and Bret)  RECORDING  SLIDES

• Recent Studies on the Health Harms Of Air Pollution and Health Benefits of Electrification,  SF Bay PSR, 04/29/26 (Bret)

Links to Previous Newsletters:

• First Quarterly Newsletter, November 4, 2024 (Fall/Winter)
• Second Quarterly Newsletter, February 13, 2025 (Winter/Spring)
• Third Quarterly Newsletter, May 27, 2025 (Spring/Summer)
• Spr/Fall Quarterly Newsletter, Sept 2, 2025
• Winter 2026 Newsletter, Dec, 2026