The Health Effects of Involuntary Exposure to Tobacco Smoke

The largest producer of secondhand smoke is cigarettes, followed by pipes and then cigars. Secondhand smoke refers to a nonsmoker’s inhalation of both the smoke exhaled by the smoker, and the “sidestream” smoke that is released by the smoldering cigarette. Secondhand smoke resembles the smoke inhaled by the smoker in that it contains many chemicals (e.g., formaldehyde, cyanide, carbon monoxide, ammonia, and nicotine) that are known carcinogens. Although adults have experienced a decline in exposure to secondhand smoke as a result of smoking restrictions in the workplace and public spaces, children continue to be exposed to secondhand smoke in the home. Among children younger than 18 years of age, an estimated 22% are exposed to secondhand smoke, also referred to as involuntary smoking.

The amount of smoke to which children are exposed varies according to the number of smokers and the rate at which they are smoking, the size of the space in which the smoking takes place, and the rate of air exchange between smoke-filled air and uncontaminated air. These variables also can affect the health effects of secondhand smoke on school-agers. As children get older, the effects of secondhand smoke decrease.

Based on several decades of sound scientific research, the Surgeon General’s 2006 report presents the following causal relationships between:

• Parental smoking and coughing, phlegm, wheezing, and breathlessness in school-age children
• Parental smoking and ever having asthma in childhood
• Secondhand smoke exposure and the onset of wheeze illnesses in childhood
• Secondhand smoke and the onset of asthma in childhood
• Maternal smoking during pregnancy and adverse effects on lung function across childhood

The report also cites previous research that demonstrates improvement in respiratory symptoms in children whose parents have stopped smoking (O’Connell & Logan, 1974).

Finally, the report suggests that separating smokers from nonsmokers within the same air space, cleaning the air, and ventilating buildings may reduce—but not eliminate—the exposure of children and adults to secondhand smoke. The scientific evidence indicates that there is no risk-free level of exposure to secondhand smoke. Only by the elimination of indoor smoking can we fully protect children from the inhalation of secondhand smoke.