• PRATHIBA RAJII M
• KARTHEEBAN B
• MANIMOZHI M
• NITHISHKUMAR M
• PRASATH S P

Alzheimer's disease affects millions worldwide, with the number of cases expected to roughly treble by mid-century. While age and the APOE ε4 gene remain the primary acknowledged risk factors, current evidence points to a subtler contributor: the air we breathe daily. This review examines epidemiological, mechanistic, and autopsy data linking ambient air pollution, namely fine particulate matter (PM2.5) and diesel exhaust, to Alzheimer's development and progression. These pollutants enter the brain through two main routes: direct olfactory nerve translocation, bypassing the blood-brain barrier, and disruption of the barrier itself after systemic absorption. Once within the CNS, they cause oxidative stress, persistent neuroinflammation, and glial activation, speeding amyloid-beta buildup, tau hyperphosphorylation, and reduced glymphatic clearance of toxic proteins. Large cohort studies from Canada, Sweden, the UK, and Taiwan consistently correlate traffic proximity and pollution exposure with greater dementia risk. This risk is significantly magnified in APOE ε4 carriers, demonstrating gene-environment interaction rather than two separate risks. Key limitations include dependence on observational and animal data, geographic emphasis on high-income countries, and near-exclusive focus on a single genetic variant. Addressing air pollution as a modifiable, population-level risk factor, alongside more geographically diverse and biomarker-driven research, could significantly improve future dementia prevention initiatives.

"The Air We Breathe and the Brain We Keep: Air Pollution as an Emerging Driver of Alzheimer's Disease", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.13, Issue 10, page no.a266-a272, October-2026, Available :http://www.jetir.org/papers/JETIR2610028.pdf

"The Air We Breathe and the Brain We Keep: Air Pollution as an Emerging Driver of Alzheimer's Disease", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.13, Issue 10, page no. ppa266-a272, October-2026, Available at : http://www.jetir.org/papers/JETIR2610028.pdf