Controlled exposures of healthy and asthmatic volunteers to concentrated ambient fine particles in Los Angeles.

Information about health effects from controlled exposure to particulate matter (PM) air pollution is relatively limited but potentially critical in urban locations such as Los Angeles, where abundant mobile sources generate combustion-related particles. Nonsmoking healthy (n = 12) and asthmatic (n = 12) volunteers, age 18-45 yr, were exposed to concentrated ambient particulates (CAP) in the fine (PM(2.5)) size range at an average concentration of 174 micro g/m(3) (range 99-224), and to filtered air (FA).