Air Pollution | A Hidden Threat to Brain Health

Air pollution has been known to pose a threat to the lungs and the heart, but recent studies reveal a worrisome link to brain health. The State of Global Air 2025 report tells us that air pollution was responsible for 626,000 deaths related to dementia in 2023, which is almost 29 percent of all dementia deaths across the world. This study was the first time that researchers were able to quantify the role of air pollutants in neurodegenerative diseases.

Air pollution has also deprived humanity of 11.6 million years of life, suggesting effects on health that go far beyond traditional chronic respiratory or cardiovascular disease. Chronic exposure to fine particulate matter–PM2.5–is a silent threat to billions of people, impacting not just their bodies but their brains.

The Impact of Pollution on the Brain

Small particles of pollution can go from the lungs into the blood supply and then the brain. In the brain, these particles initiate inflammation and oxidative stress which injure brain cells and may lead to disorders such as Alzheimer’s disease, vascular dementia, and mild cognitive impairment. The cumulative effects of these disorders can lead to a gradual decline in memory, reasoning, and independence.

Air pollution does not just affect the elderly. Young people are also at risk, as exposure to pollution is likely to disrupt brain development and contribute to neurodevelopmental disorders such as autism, as well as mental health disorders or issues such as anxiety and depression.

Although there are possible lifestyle risk factors for dementia such as smoking, poor diet, and lack of exercise, pollution is unique because billions of people across the globe are affected by air pollution so that even a small risk factor for an individual can lead to a significant burden in public health terms.

A Gendered Impact

The crisis of dementia has a gendered component. Women are more likely to receive a diagnosis of dementia and frequently are the caregivers for someone with dementia in their family. This “double burden” can amplify the social and economic costs of the illness-disproportionately in low- and middle-income countries with fewer health service resources.

In 2021, approximately 60 million people lived with dementia globally, with around 10 million new cases diagnosed annually. Globally as our population becomes older, especially in areas of high pollution, we can expect the number of cases to increase.

The Age Factor

Older adults can be substantially more vulnerable to the long-term effects of air pollution. In 2023, nearly 86% of deaths related to pollution were caused by noncommunicable diseases such as heart disease, diabetes, COPD, and dementia. For older adults, the aging process adds an additional risk factor-increased environmental exposure to pollution and decreased physiological reserve.

Areas such as South Asia, along with many parts of Africa, carry the most weight, with India and China combined responsible for more than 50 percent of pollution-related deaths.

The Critical Need of Cleaner Air

Experts say the potential benefits of reducing air pollution are extensive, from lowering healthcare costs to a longer healthy life to even slowing climate change. Pallavi Pant, who leads global initiatives at the Health Effects Institute in Boston, says clean air policies are essential to promoting public health. Pant states the findings of the report should compel governments, especially those regions hit hardest, to act now.

“Many of the decision-makers are at an age when you’re seeing the effects of pollution, so the best way to protect health and quality of life is to move toward clean air,” Pant said.

The relationship between air pollution and the health of the brain is disconcerting. It is just another argument for progressive environmental policy, global consciousness and acting now to better the lungs and minds of billions. Cleaner air means more than it’s easier to breathe; it means clearer thinking and longevity.