Impact of Particulate Matter Exposure on Neurological Health in Older Adults: A Systematic Review

Purpose of Review This systematic review evaluates the current epidemiological evidence on the relationship between particulate matter (PM) exposure and neurological health in older adults, with particular attention to cognitive decline and neurodegenerative disease. Recent Findings A PRISMA-guided systematic search of PubMed, Scopus, Web of Science, and ScienceDirect was conducted through January 2026. Twenty-one observational studies met the inclusion criteria. The most frequently studied outcomes were cognitive performance and decline and cognitive impairment, including mild cognitive impairment (MCI), with several studies reporting adverse associations, particularly for long-term PM2.5 exposure. Evidence for dementia and Alzheimer’s disease was also provided by several large cohort studies, although findings varied across exposure metrics and clinical endpoints. In contrast, evidence for Parkinson’s disease-related hospitalizations, cerebral amyloid burden, retinal neurodegeneration, mental disorder-related hospital admissions, and individual PM constituents was more limited and was often based on one or a few studies. Findings concerning specific PM constituents were heterogeneous and should therefore be considered exploratory. Summary The available evidence suggests an association between PM exposure and adverse neurological health in older adults, with the most substantial evidence concerning long-term PM2.5 exposure and cognitive outcomes. However, the strength and certainty of the evidence vary considerably across pollutants and neurological endpoints. Heterogeneity in study design, exposure assessment, and outcome definitions should be considered when interpreting the overall findings.