We’ve all heard of “second hand smoke,” the result when smokers exhale and release carcinogens into the air around them. The harmful effects of passive smoking are well documented. Third-hand smoking is less well known.
Coined in 2009 by doctors at the Mass General Hospital for Children, the term is used for the residual gases and particles from tobacco smoke that cling to clothing, hair, skin, carpets, upholstery, and even wallpaper.
We’ve all caught the smell of smoke after a smoker exits a confined space…this is a real-world example of third-hand smoke, according to new research.
Science has long known that tobacco smoke is absorbed by surfaces; Until now, no one had looked at what might happen when these residual molecules come into contact with common pollutants in the atmosphere.
Scientists at Lawrence Berkeley National Laboratory conducted laboratory tests and found “significant levels” of toxins on smoke-exposed material. Such residues can react with a common indoor pollutant to produce hazardous chemicals known as tobacco specific nitrosamines (TSNAs). These residues can linger for weeks or even months.
Smokers who may not give in to their children, or who smash the car window and smoke with their children behind them, are unknowingly exposing them to heavy metals, carcinogens and even radioactive materials long after the cigarette smoke has cleared.
According to the researchers, third-hand smoking is an unappreciated health risk, fueling the anti-smoking movement and the call for bans on smoking in homes, vehicles, hotels and other public places. Young children are particularly vulnerable because they breathe in close proximity to these surfaces and do not hesitate to lick or suck on them.
The tests exposed contaminated surfaces to high but reasonable levels of nitrous acid, a fairly common thing in the air that can come from unvented gas appliances as well as most car engines and exhaust fumes.
Exposure increased the concentration of newly formed TSNAs tenfold. Traces of TSNAs were also seen on the interior surfaces of a truck owned by a heavy smoker.
Lawrence Berkeley National Laboratory researcher Lara Gundel admits: “Smoking outside is better than smoking inside, but nicotine residues stick to a smoker’s skin and clothing. These residues follow a smoker back inside and spread everywhere. Think of the lingering smell after a smoker comes back in after a “smoke break”.
Of course, advocates of smoking are skeptical about the danger. Simon Clark, director of UK smoking lobby group Forest, said: “The dose makes the poison and there is no evidence that exposure to such small amounts is harmful. However, that doesn’t seem to matter. The goal, it seems, is to sound the alarm in the hope that people will be discouraged or quit smoking.”
Whatever your beliefs, the new work suggests that making your home and vehicle smoke-free is a smart choice, especially if you have young children.
You can also limit exposure to third-hand smoking and its after-effects as much as possible – wash your hands, change clothes, brush your teeth after smoking and before holding or feeding babies and young children.
Thanks to Kirsten Whittaker
