"Thirdhand" smoke – the residue from leftover cigarette smoke that clings to walls and furniture – has been found to pose a cancer risk, especially to young children who put toys and other smoke-affected items into their mouths.
In new research presented at meeting of the American Chemical Society in Dallas this week, scientists from the Lawrence Berkeley National Laboratory reported one of the tobacco-specific nitrosamines in thirdhand smoke damages DNA and sticks to it in a way that could potentially cause cancer.
Bo Hang, who presented the research, said that although the idea of thirdhand smoke is a relatively new phenomenon, only making its debut in research circles in 2009, evidence already strongly suggests it could threaten human health.
"The best argument for instituting a ban on smoking indoors is actually thirdhand smoke," said Hang, a scientist at Lawrence Berkeley.
Researchers have found that many of the more than 4,000 compounds in secondhand smoke can linger indoors long after a cigarette is stubbed out. Previous research at Lawrence Berkeley has found these substances can react with indoor pollutants, such as ozone and nitrous acid, creating new compounds, some of which may be carcinogenic.
One of those compounds goes by the acronym NNA. Hang's research has shown that NNA, a tobacco-specific nitrosamine, damages DNA and locks onto it so that it can bind to a cancer-causing chemical in lab test tubes. That, in turn, can lead to uncontrolled cell growth and the formation of cancerous tumors.
The biggest potential health risk is for babies and toddlers, who could touch, swallow or inhale compounds from thirdhand smoke. Their small size and early developmental stage make them more vulnerable than adults to the effects of environmental hazards.
Removing affected items, such as sofas and carpeting, as well as sealing and repainting walls, and replacing contaminated wallboard can reduce risks, the researchers said. But vacuuming and washing clothes, curtains, and bedding can also help
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