passive smoking

passive smoking, the inhalation by nonsmokers of the smoke from other people’s cigarettes, pipes, or cigars. The amount of such smoke inhaled by a nonsmoker is small compared with that inhaled by tobacco users. However, passive smoking can aggravate respiratory illnesses and contribute to serious diseases, including cancer. Infants, fetuses, and individuals with chronic heart and lung diseases or allergies to tobacco can be adversely affected by passive smoking. See also secondhand smoke.