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Last updated
July 26, 2025

Dementia

Air pollution and dementia research builds on growing evidence that environmental pollutants significantly accelerate cognitive decline and increase dementia risk. Long-term exposure to particulate matter, nitrogen dioxide, and other common pollutants has been linked to earlier onset and more rapid progression of various forms of dementia. The mechanisms involve neuroinflammation, oxidative stress, and direct damage to brain tissue from pollutant particles that can cross the blood-brain barrier. Explore the compelling research connecting air quality to dementia risk and what this means for prevention strategies.
  • Replicable studies found evidence linking long term air pollution exposure with incident dementia (Griffiths & Mudway, 2018)
  • Significant positive association between higher levels of pollution exposure and dementia diagnosis (Carey et al., 2018)
  • There is a 40% higher risk of dementia between those living in the highest quintile of nitrogen dioxide and those in the lowest quintile (Carey et al., 2018)
  • “Exposure to ambient nitrogen dioxide and fine particulate matter was associated higher incidence of dementia” (Chen et al., 2017)
  • 6.1% of total cases could be attributed to elevated exposure to air pollution (Chen et al., 2017)
  • PM2.5 and NO2 both associated with increased risk and incidence of dementia (Chen et al., 2017)
  • Higher PM2.5 levels associated with more dementia cases (NIH, 2023)
  • Close to 188,000 cases of dementia every year might be due to PM2.5 (NIH, 2023)
  • Increased exposure of air pollutants associated with increased use of CMHTs (community mental health teams) in a dose-response manner (Ronaldson et al., 2023)
  • PM associated with dementia first hospitalization, progression, etc (Ronaldson et al., 2023)
  • Long term exposure associated with more frequent use of CMHT particularly for PM2.5 (particulate matter) and NO2 (nitrogen dioxide), particularly for those with vascular dementia (reduced blood flow to brain) (Ronaldson et al., 2023)
  • Dementia is leading cause of death in UK with air pollution as a potential risk factor (Ronaldson et al., 2023)
  • Women had “higher risk for decreased cognitive function associated with increased exposure to PM10 and PM2.5-10” (Kim et al., 2019)
  • Poor air quality linked to dementia onset in Danish Nurse Cohort study.  1,409/25,233 nurses diagnosed with dementia with median age of 79.1 years, and tended to live in urban areas (Day, 2024)
  • Wildfire smoke exposure correlated with 21% increase for risk of dementia diagnosis in California (Gammon, 2024)

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