You're coughing. You're waving it away. Not only does it smell bad, but you're also worried it might give you cancer or other lung ailments.
It's secondhand smoke, of course. You're thinking to yourself, "I'm not silly enough to actually smoke cigarettes and I'm sure enough not going to fall victim to someone else's."
And so you walk away. Into another room in this smoker's home. "Ah," you think to yourself, "I'm away from all that toxicity."
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Except you are not. You are now entering the realm of thirdhand smoke.
Have you ever been in a hotel where the only rooms remaining are on a smoking floor? Doesn't smell too good? That's where thirdhand smoke lives. In the drapes. In the carpet. In the bedspread. In the ceiling tiles.
And, according to researchers, it can do you – and, more particularly, young children – harm. A study by scientists at the Department of Energy's Lawrence Berkeley National Laboratory found that newborn mice that lived in cages containing smoke-treated fabric for three weeks weighed significantly less than their counterparts in a control group. In addition, both newborn and adult mice exposed to thirdhand smoke experienced changes in blood cell counts associated with the immune system, leading to inflammatory and allergic reactions.
The research team believes the results of the mice experiment can apply to humans, too.
"We suspected that the young are most vulnerable because of their immature immune systems, but we didn't have a lot of hard evidence to show that before," said study lead author Bo Hang, a Berkeley Lab staff scientist who previously found that thirdhand smoke could lead to genetic mutations in human cells. "In this case, we found that thirdhand smoke appeared to inhibit weight gain in neonatal mice."
In a paper published in the journal Scientific Reports, Hang's team noted that human babies and toddlers are at greater risk because they come into contact with contaminated surfaces while crawling on carpets and sleeping on smoke-infused bedding.
"Those are all types of white blood cells associated with inflammation and allergic reactions," said Jian-Hua Mao, another member of the team, which is based at the University of California-Berkeley. "And the effects on blood cell count persisted even after exposure ended …at least 14 weeks after exposure ended for the neonatal group, and two weeks after it ended for the adults."
But health threats can persist even longer, says a report by the Respiratory Health Association (RHA), a lung health non-profit based in Chicago, if the thirdhand smoke environment is permanent. "When residual nicotine reacts to certain chemicals in the air it forms cancer-causing agents that continue to develop over time," says an RHA paper. "Also, when nicotine reacts with ozone in the air it forms 'ultrafine' particles, which can transport harmful chemicals."
So how do you reduce the risks? Stop smoking and start ripping everything out, the RHA says.
"Simply cleaning does not completely remove thirdhand smoke contaminants from a room," the scientists report. "Tests have found measurable levels of nicotine in new residents of formerly-smoking homes and hotel rooms – even after the unit has been professionally cleaned and left unoccupied for months. In such properties, it may be necessary to replace carpeting, wall boards, counters, and furnishings to completely eliminate exposure to tobacco-specific toxins and carcinogens."
It might be cheaper – and healthier – to find a place where no one has been puffing away.