ABSTRACT
This chapter explores the relationship between inhaled atmospheric particulate matter (PM) and the potential for oxidative injury to the lung. Reactive oxygen species are necessary for the normal functioning of cells, and, usually, there is little release from the cell; reactive oxygen species that escape are readily intercepted by cellular antioxidant defenses. Compared to larger particles, ultrafine particles have a greater particle number and a greater surface area per unit mass of inhaled particles; both of the characteristics influence toxic potential. In more studies, epidemiologic evidence has linked small but significant increases in human morbidity and mortality with PM for different cities in the world. Reactive oxygen species and other substances released into the cytoplasm may damage or kill other phagocytic cells, which, in turn, release toxic and proteolytic enzymes and substances that attract fibroblasts and elicit fibrogenic responses.
