The health implications for smokers and those exposed to second-hand smoke are well known, but now a pioneering study has uncovered that even third-hand smoke causes significant genetic damage that could lead to cancer.
Long after smoking has stopped, residual nicotine clings to hair, skin, clothes, and surfaces like benches and walls, drapes, bedding, carpets and our vehicles. It is this residual nicotine that scientists have found to cause genotoxicity – a known risk in the development of cancer and other diseases.
The findings, published in the journal Mutagenesis, are significant for children who are exposed to third-hand smoke by parents or elders – many of whom are under the illusion that opening a window for fresh air to blow away the smoke is preventing them from putting others health at risks.
Infants are at a high risk of tobacco-related health problems when they inhale, ingest or touch surfaces that contain third-hand smoke, the researchers from the Lawrence Berkeley National Laboratory in California say.
“This is the very first study to find that third-hand smoke is mutagenic,” said Lara Gundel, one of the study’s researchers. “Tobacco-specific nitrosamines, some of the chemical compounds in third-hand smoke, are among the most potent carcinogens there are. They stay on surfaces, and when those surfaces are clothing or carpets, the danger to children is especially serious.”
The findings also uncovered that chronic exposure to third-hand smoke is much worse than acute exposure – with samples suggesting that the nicotine residue becomes more harmful over time.
Third-hand smoke is also particularly dangerous because it is extremely difficult to eradicate. Studies have found traces of the residual nicotine can still be detected in the surfaces of homes smokers more than two months after they’ve moved out.
Conventional cleaning methods like vacuuming, wiping and ventilation where found to have little effect in lowering nicotine contamination.
“Until this study, the toxicity of third-hand smoke has not been well understood,” the study’s lead researcher Bo Hang said. “Third-hand smoke has a smaller quantity of chemicals than second-hand smoke, so it’s good to have experimental evidence to confirm its genotoxicity.”
“You can do some things to reduce the odours, but it’s very difficult to really clean it completely,” the researchers advised. “The best solution is to substitute materials, such as change the carpet, repaint. Third-hand smoke could become more harmful over time.”