Controlled Exposure of Healthy Nonsmokers to Secondhand and Thirdhand Cigarette Smoke

Thirdhand cigarette smoke is the smoke chemicals that persist in the environment after smoking. Indoors, they can be found both on surfaces and in the air. Thirdhand smoke derives from secondhand smoke and contains the chemicals that stick to surfaces, are re-emitted into the air and that form by chemical reactions both on surfaces and in the air. Thirdhand smoke can contain higher concentrations of the tobacco-specific nitrosamine and known carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) than secondhand smoke, because nicotine reacts to form NNK in the indoor environment. Dermal exposure to thirdhand smoke includes nicotine, NNK and other tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, and volatile organic compounds. Inhalational exposure to thirdhand smoke includes nicotine, ultrafine particles and volatile organic compounds. Previous studies have shown that inhalational exposure to secondhand cigarette smoke causes endothelial dysfunction, which is a risk factor for heart disease and heart attacks.