Air Pollution’s Link To Amyotrophic Lateral Sclerosis (ALS) – CleanTechnica

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Air pollution from fossil fuels is the main contributor to climate change. The damage caused by air pollution doesn’t stop there; it also contributes to human diseases, suffering, and premature deaths.

Indu Navar, an expert researcher, caregiver, and nonprofit founder, answered some questions for us about air pollution exposure and amyotrophic lateral sclerosis (ALS). She is one of the founders of Everything ALS.

How is increased sulfur dioxide (SO₂) exposure associated with the development of ALS?

Recent population-level research links long-term SO₂ exposure with higher odds of developing ALS. 

A 2025 Canadian study found that SO₂ exposure 5–10 years before onset was significantly associated with ALS, SO₂ has a real environmental risk factor in ALS.  ScienceDirect+1

How are people exposed to SO₂?

People are mainly exposed by breathing outdoor air polluted by fossil-fuel combustion like power plants, industrial facilities, some shipping and refining, with additional contributions from certain workplaces and from wildfire smoke. 

Is there anything we can do to reduce or eliminate that exposure?

• At the community and policy level, we need to cut sulfur emissions from power/industry and heavy transport; meet or exceed EPA Guidelines and align with WHO Air Quality Guidelines.
• At a personal level, we should check daily AQI and limit strenuous outdoor activity where SO₂ may be elevated; prioritize clean indoor air with HEPA filtration.
• Also we should reduce indoor combustion and use induction, seal/maintain appliances and furnaces; during smoke episodes or near point sources, consider a well-fit N95 if you must be outside. It is crucial to follow general health guidance on SO₂ and particle exposure mitigation.

What is your personal relationship with ALS?

I lead EverythingALS (the Peter Cohen Foundation) and work directly with people living with ALS, caregivers, neurologists, and industry/regulatory partners to co-create digital endpoints and accelerate trials, turning lived experience into measurable, actionable data across speech, movement, and daily-life signals. 

Why did you found your organization and what does it do?

I funded EverythingALS to make medicine more human by listening to people with ALS and translating their needs into tools that speed discovery and reduce trial burden. We run longitudinal studies, develop digital biomarkers, and convene multi-stakeholder collaborations so companies and sites can run faster, more inclusive trials that measure what matters to patients and families. 

Are most cases of ALS thought to not be based in genes?

Yes. About 90–95% of ALS cases are “sporadic” (no known family history); ~5–10% are familial with identifiable heritable variants in many of those families. Even in sporadic ALS, genes and environment likely interact. 

Is particulate matter (PM) associated with ALS and/or other neurodegenerative disease?

Evidence for PM and ALS is mixed but growing: several studies examine PM₂.₅/PM₁₀ and ALS mortality or risk, with some positive signals and some null findings; by contrast, SO₂ showed a clearer association with ALS in the 2025 study above. ScienceDirect

For other neurodegenerative diseases, the association with fine particulates (PM₂.₅) is stronger: systematic reviews and large cohorts link long-term PM₂.₅ exposure with higher risks of dementia (including Alzheimer’s) and Parkinson’s, plausibly via neuroinflammation, oxidative stress, and vascular pathways. 

Air pollution including SO₂ and PM can trigger systemic and brain inflammation, oxidative stress, and blood-brain-barrier disruption; animal and human studies show pollutant particles reaching the brain and up-regulating proteinopathies implicated in neurodegeneration (e.g., amyloid-β, α-synuclein). These pathways provide biologic plausibility for the epidemiologic signals.

https://pubmed.ncbi.nlm.nih.gov/28123818/