Ambient air pollution is a key modifiable disease risk factor producing detrimental health effects on millions of people across the world. In the United States, the Environmental Protection Agency has set National Ambient Air Quality Standards for 6 criteria pollutants routinely measured across the country and considered harmful to public health: particulate matter (PM), ozone, nitrogen and sulfur dioxides, lead, and carbon monoxide.
Outdoor air pollutant exposures include complex mixtures of PM, gases, and organic (including polycyclic aromatic hydrocarbons [PAHs]) and inorganic compounds emitted directly into the air mainly from combustion of fossil fuels from gas, oil, coal, industry, and fires.
Calderón-Garcidueñas L, Torres-Jardón R. The Impact of Air Pollutants on the Brain. JAMA Psychiatry. 2015;72(6):529-530. doi:10.1001/jamapsychiatry.2015.0192