Air pollution was significantly associated with an increased risk of hospital admissions for several neurological disorders, including Parkinson’s disease, Alzheimer’s disease, and other dementias, in a long-term study of more than 63 million older U.S. adults, led by researchers at Harvard T.H. Chan School of Public Health.

The study, conducted with colleagues at Emory University’s Rollins School of Public Health and Columbia University’s Mailman School of Public Health, is the first nationwide analysis of the link between fine particulate (PM2.5) pollution and neurodegenerative diseases in the U.S. The researchers leveraged an unparalleled amount of data compared to any previous study of air pollution and neurological disorders.

The study was published online October 19, 2020 in The Lancet Planetary Health.