Passive Smoking in the Workplace: Selected Issues (Part 6 of 10)

components to the air that are qualitatively similar to the smoke taken into smokers’ lungs. The levels of these constituents to which nonsmokers are exposed are much lower levels to which smokers are exposed, and the levels vary depending on the amount of smoking around the nonsmoker, the architecture and ventilation of the structure, other aspects of air quality (e.g., humidity), and chemical and physical changes that take place in the air. Nevertheless, the major components of tobacco smoke have been repeatedly detected in enclosed spaces in which there has been smoking, at higher levels than occur in the absence of smoking. Biologic measurements of tobacco smoke constituents and their metabolizes in nonsmokers provide direct, convincing evidence that nonsmokers do have measurable internal exposure to environmental tobacco smoke, and that levels of exposure are related to the number of cigarettes and/or smokers to which they are exposed.