Environmental Tobacco Smoke: Experimental Facts and Societal Issues

Involuntary exposure to environmental tobacco smoke (ETS) inpublic or in working places is considered to be a serious riskto human health. This symposium addressed several issues oftoxicological interest that are associated with exposure toETS. Epidemiologic evidence obtained in human studies suggeststhat "passive smoking" increases the risk of developing lungcancer in nonsmokers and favors the development of respiratorytract infections in children. Comparatively few data are availablefrom animal studies that provide experimental support of theobservations. Exposure of pregnant or neonate rats to cigarettesidestream smoke (SS) affects developmental patterns of drugmetabolizing enzymes that may persist up to 90 days. In youngroosters, SS accelerates the development of arterioscle-roticplaques. On the other hand, exposure of adult rats for up to90 days induces only transient signs of damage in the nasalpassages, but not in the deep lung, and this only at extremelyhigh concentrations of ETS. So far, experimental toxicologyhas provided comparatively few data on the correlation betweenexposure to ETS and adverse health effects. Yet, such data areneeded, particularly since many conclusions drawn from the epidemiologicalstudies remain open to criticism and questions.