APOE and Alzheimer disease: Chronic exposure to air pollutants, such as particulate matter, black carbon, ozone, and persistent organic pollutants, has been associated with neurotoxicity via increased production of proinflammatory cytokines, mitochondrial dysfunction, and alteration of DNA methylation patterns within neurons and glial cells [157, 158]; interestingly, sensitivity to air pollutants seemed to be enhanced by genetic factors, as shown among ApoE ɛ4 carriers with AD [159] and leucine-rich repeat kinase (LRRK) carriers with PD [160].