Compr Physiol

Researchers have been studying the respiratory health effects of ambient air pollution for more than 70 years. While air pollution as a whole can include gaseous, solid, and liquid constituents, this article focuses only on the solid and liquid fractions, termed particulate matter (PM). Although PM may contain anthropogenic, geogenic, and/or biogenic fractions, in this article, particles that originate from microbial, fungal, animal, or plant sources are distinguished from PM as bioaerosols. Many advances have been made toward understanding which particle and exposure characteristics most influence deposition and clearance processes in the respiratory tract. These characteristics include particle size, shape, charge, and composition as well as the exposure concentration and dose rate. Exposure to particles has been directly associated with the exacerbation and, under certain circumstances, onset of respiratory disease. The circumstances of exposure leading to disease are dependent on stressors such as human activity level and changing particle composition in the environment. Historically, researchers assumed that bioaerosols were too large to be inhaled into the deep lung, and thus, not applicable for study in conjunction with PM| (the 2.5-\u3bcm and below size fraction that can reach the deep lung); however, this concept is beginning to be challenged. While there is extensive research on the health effects of PM and bioaerosols independent of each other, only limited work has been performed on their coexposure. Studying these two particle types as dual stressors to the respiratory system may aid in more thoroughly understanding the etiology of respiratory injury and disease. \ua9 2020 American Physiological Society. Compr Physiol 10:1-20, 2020.P51 OD011107/OD/NIH HHS/United StatesT32 ES007059/ES/NIEHS NIH HHS/United StatesU01 OH010969/OH/NIOSH CDC HHS/United StatesP30 ES023513/ES/NIEHS NIH HHS/United StatesU54 OH007550/OH/NIOSH CDC HHS/United StatesU01 ES027288/ES/NIEHS NIH HHS/United StatesU01 OH010839/OH/NIOSH CDC HHS/United States2020-10-13T00:00:00Z31853953PMC7553137852