You may think of leftover cigarette smoke that clings to walls and furniture as simply a smelly nuisance - but now research suggests that it could be far more dangerous, especially to young children who put toys and other smoke-affected items into their mouths.
According to scientists, one compound from ‘third-hand smoke’, which forms when second-hand smoke reacts with indoor air, damages DNA and sticks to it in a way that could potentially cause cancer.
Although many public places prohibit smoking in the US, people still smoke in most rental apartments and private residences and it remains a huge public health issue. In 2011, nearly 44 million American adults reported smoking cigarettes, which is the leading cause of preventable death. According to data from the Centers for Disease Control & Prevention (CDC), 34 million people smoke every day.
Although the idea of third-hand smoke was initially only described in 2009, available evidence already suggests it could seriously threaten human health. In fact, the best argument for instituting a ban on smoking indoors is actually third-hand smoke, according to health experts.
Many of the more than 4,000 compounds in second-hand smoke released as a cigarette is smoked can linger indoors long after a cigarette is put out. Studies show that these substances can go on to react with other indoor pollutants such as ozone and nitrous acid, creating brand-new compounds - some of which may be carcinogenic.
One of those compounds is known as NNA. Ongoing research shows that NNA locks onto DNA in a way that’s similar to other large compounds that attach to DNA and causes genetic mutations. NNA also breaks DNA strands in laboratory experiments - this kind of DNA damage can lead to uncontrolled cell growth and the formation of cancerous tumors.
Making the connection between third-hand smoke or NNA and cancer could take a while - however, early research into NNA was compelling enough that a research consortium dedicated to investigating third-hand smoke was formed in California in 2010.
The biggest potential health risk from third-hand smoke is for babies and toddlers. As they crawl and put their hands or toys in their mouths, they could touch, swallow or inhale dangerous compounds from third-hand smoke. Their small size and early developmental stage make them more vulnerable than adults to the effects of environmental hazards.
The best way to get rid of third-hand smoke is by removing affected items, such as sofas and carpeting, sealing and repainting walls - and sometimes even replacing contaminated wallboard. Additionally, vacuuming and washing clothes, curtains and bedding can also help get rid of third-hand smoke.