Long-term exposure to ambient air pollution, APOE-ε4 status, and cognitive decline in a cohort of older adults in northern Manhattan.

•Ambient air pollution is associated with more rapid cognitive decline in older adults.•APOE-ε4 positive individuals had more rapid pollution-associated cognitive decline.•The association was also stronger among Non-Hispanic individuals.•No difference in strength of association between age groups, sex, or smoking status.