Evidence presented at the 247th National Meeting and Exposition of the American Chemical Society warns that thirdhand smoke damages DNA, attaching to it in a way that may result in cancer.
The talk, titled "Thirdhand smoke causes DNA damage in human cells," was presented by Bo Hang, PhD, a scientist at Lawrence Berkeley National Laboratory in California, who in 2013 published a study of the same name in the journal Mutagenesis.
Thirdhand smoke - exposure to the toxic compounds of tobacco smoke from surfaces and dust in a room or car where someone has previously been smoking - is a relatively recent area of study, with the first scientific research into the subject appearing in 2009.
In 2010, a consortium was formed in California to investigate the effects of thirdhand smoke. This consortium funded Dr. Hang's research and has been working to understand the public health implications of thirdhand smoke.
Researchers have found that many of the 4,000 pollutants from smoke have been identified in carpets, walls, furniture and dust, as well as on the clothing, hair and skin of smokers. People can be exposed to these pollutants by inhaling, touching or ingesting them.
But some of the surface-absorbed residue from tobacco smoke can also produce additional toxicants, undergoing a chemical transformation when it interacts with compounds in the atmosphere.
What is 'NNA' and why is it of concern?
One of these secondary compounds is 4-(Methylnitrosamino)-4-(3-pyridyl)-butanal, or "NNA" for short. Hang and his colleagues have found that NNA attaches itself to DNA to create a cancer-causing chemical.
Surface-absorbed tobacco residue can undergo a chemical transformation when it interacts with compounds in the atmosphere, creating new pollutants.
Both NNA and another compound called 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone), or "NNK," break down DNA. This damage to DNA can lead to cell growth becoming uncontrolled and the formation of cancerous tumors.
Though compelling, this research is still in an early phase. Dr. Hang thinks that just as it took a long time to conclusively establish a connection between firsthand smoke and cancer, it could be years before the connections between thirdhand smoke, NNA and cancer are conclusive.
Medical News Today have reported on other studies warning that thirdhand smoke is just as harmful as firsthand smoke. Some scientists have found that thirdhand smoke is linked to liver, lung and skin problems.
According to the Centers for Disease Control and Prevention (CDC), 34 million Americans smoke every day. As a result, smoking is the leading cause of preventable death in the US.
The best way to reduce a risk of exposure to thirdhand smoke is simply by removing contaminated furniture and carpeting, and sealing and repainting walls and other surfaces.
Hang thinks that babies and toddlers are particularly at risk from thirdhand smoke. Not only are they more vulnerable to the adverse effects of tobacco residue because they are still developing, but they are also more likely to touch, swallow or inhale toxic smoke compounds as they crawl and put their hands or toys in their mouths.
Recently, scientists have also examined whether e-cigarettes present any thirdhand smoke risk.