The harmful effects of second-hand smoke have been well researched and documented, but what about third-hand smoke? Traces of nicotine linger on clothes, skin and surfaces for hours (or even days) after the smoker has extinguished her cigarette, and they have the potential to harm other people. Studies on third-hand smoke are scarce, but the more resesarch scientists compile, the more evidence points toward the potential problems third-hand smoke might cause or exacerbate, especially among children.
In a 2010 study, researchers found that "nicotine will stick to these surfaces for days and interact with nitrous acid (present when nitrous oxide is emitted by gas appliances) to form carcinogenic tobacco-specific nitrosamines," reports Wired UK. Now, a study following up on that finding investigates the health impacts of those carcinogenic nitrosamines. Researchers exposed random household surfaces (including car interiors) to second-hand smoke for six hours per day over a six month period. Then, they exposed young mice to those surfaces.
Even though the mice's cages were ventilated, the animals exhibited some suspect symptoms. Some of the mice's wounds took longer to heal, Wired reports, while others were hyperactive and anxious. After six months, the mice had increased levels of fat in their liver, putting them at risk for cirrhosis of the liver and cancer, Wired continues.
All of these issues, the study's authors point out, correspond to real-world issues smokers and their children often exhibit. Of course, mouse trials do not definitively prove that third-hand smoke might alter some children's physical and mental health, but the result should concern smokers, who, Wired points out, for the most part are not worried that third-hand smoke will hurt kids.