Air Pollution and Parkinson's Disease Pathology: Clinical Evidence and the Molecular Mechanisms Linking Airborne Toxicants to Neuroinflammation and Neurodegeneration.

Parkinson's disease (PD) is a neurodegenerative condition, and its rising prevalence necessitates the urgent need to identify modifiable risk factors. Air pollution, a pervasive and also escalating public health problem, has emerged as a potential contributor to the incidence and progression of PD. As urbanization and industrialization continue to exacerbate global air pollution levels, understanding the relationship between airborne toxicants and PD is a pressing scientific and public health priority. In this review, we critically discuss the current epidemiological evidence and the cellular and molecular mechanisms underlying air pollution-induced neurodegeneration in PD. Clinical studies associate long-term interaction with pollutants such as nitrogen oxides, particulate matter, and ozone with increased PD risk. Evidence also suggests that air pollution worsens PD prognosis. Mechanistically, air pollution is hypothesized to contribute to PD pathogenesis through gut microbiome alternations, oxidative stress, and neuroinflammatory pathways, as well as promoting α-synuclein aggregation.