Involuntary Smoking—A Hazard to Children

Abstract

Children who live in households with smokers are involuntarily exposed to sidestream and secondhand cigarette smoke. The health hazards that result from passive smoking will be reviewed. This statement updates a 1982 American Academy of Pediatrics statement on the environmental consequences of tobacco smoking.1 COMPOSITION OF SIDESTREAM AND SECONDHAND SMOKE Sidestream smoke arises from the burning end of a cigarette.2,3 Secondhand or exhaled mainstream smoke is drawn into the respiratory tract of the smoker and then is exhaled. Both sidestream and secondhand smoke contain measurable quantities of such toxins as carbon monoxide (CO), ammonia, nicotine, and hydrogen cyanide. They also contain carcinogens, including benzo[a] pyrene, dimethylnitrosamine, tar, formaldehyde, and β-naphthylamine.2 Concentrations of most of these materials are higher in sidestream than in mainstream smoke.2 Air-sampling surveys have documented the involuntary exposure of nonsmokers to the products of cigarette combustion.2,3 These studies have shown that smoking in enclosed rooms can produce CO levels greater than the national ambient air quality standard of 9 ppm.4 Similarly, elevated concentrations of airborne nicotine, benzo[a] pyrene, and suspended particulates have been documented.4 Biologic evaluations of nonsmokers involuntarily exposed to cigarette smoke have demonstrated elevations of 1% to 3% in carboxyhemoglobin concentration.5 Biologic evaluations of involuntary smokers have also found increased levels of nicotine and of cotinine,6,7 the major metabolite of nicotine, in the urine and saliva. In addition, studies have demonstrated increased activity of enzymes that metabolize benzo[a]pyrene in the placentas of women who smoke8 and, possibly, in the placentas of women involuntarily exposed to cigarette smoke.9