Smoking cigarettes is the most important single cause of lung cancer. Second-hand smoke, mainly from sidestream smoke and exhaled smoke, contains the same carcinogens to which smokers are exposed and can be a cause of lung cancer in a non-smoker. The lung cancer risk in a non-smoker exposed to secondhand smoke is far less than that of a smoker, however, because the carcinogen dose is generally less than 10% of that experienced by a smoker. Third-hand tobacco smoke (“residual smoke”) consists of material remaining on surfaces and in dust in rooms where smoking has taken place.
There are limited data indicating the detectable presence of nicotine, 3-ethenylpryridine and various polycyclic aromatic hydrocarbons (PAHs) in third-hand smoke. More recently, researchers (Thomas JL, et al. Thirdhand tobacco smoke: A tobacco-specific lung carcinogen on surfaces in smokers’ homes. Nicotine Tob Res, 2014; 16 : 26-32) detected 4-(methylnitosamino)-1-(3- pyridyl)-1-butanone (“NNK”), a potent lung carcinogen from cigarettes on the surfaces within homes of smokers.
Thus, third-hand or residual tobacco smoke is a potential source of lung carcinogens. Human health studies on the long-term health effects of third-hand smoke exposure are lacking, however. Moreover, the amount of carcinogens detected are relatively small when compared to that delivered in the smoke of a cigarette. Based on the potential for carcinogen exposure, perhaps buyers or renters of homes or apartments should be notified whether smokers lived there previously.