Most of the smoke in a room results from sidestream smoke. When nonsmokers breathe in this type of smoke from other people's cigarettes, cigars, and pipes, it is often called involuntary or passive smoking. The fact that cigarette smoking is the main cause of lung cancer in smokers is well-known. In 1986 the Surgeon General of the United States reported that involuntary smoking can cause lung cancer in healthy nonsmokers. Recent studies also indicate that secondhand smoke causes death from heart disease.
Secondhand smoke has an especially bad effect on infants and children whose parents smoke.
A number of studies show that in their first two years of life, babies of parents who smoke at home have a much higher rate of lung diseases such as bronchitis and pneumonia than babies with nonsmoking parents. And smoking by pregnant women seems to predispose premature babies to respiratory distress syndrome. Parents who smoke at home can aggravate symptoms in some children with asthma and even trigger asthma episodes. Parents should only smoke outside the home or, better yet, quit smoking altogether. Even among children without asthma, a team of researchers found that acute respiratory illnesses happen twice as often to young children whose parents smoke around them as compared to those with nonsmoking parents.