Third-hand smoke can damage DNA

The health hazards linked to smoking and inhaling of second-hand smoke are well-known. But for the first time researchers have found that effects of third-hand smoke, the toxic residue that clings to surfaces after second-hand smoke has cleared out, are also damaging.

According to the findings of a new study, nicotine residue that sticks to body parts and surfaces like walls, furniture, sheets and remains there even long after cessation of smoking can cause significant genetic damage to human cells, causing many types of cancers.

“This is the very first study to find that third-hand smoke is mutagenic,” said Lara Gundel, a Berkeley Lab scientist and study’s lead researcher. “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 study, conducted by the researchers from the Laurence Berkeley National Laboratory at the University of California, also found that effects of third-hand smoke are more harmful over time.

The study
To generate third-hand smoke samples, researchers kept paper strips in smoking chambers. While acute samples were picked from chambers exposed to five cigarettes smoked in about 20 minutes, chronic samples were collected from areas that were exposed to cigarette smoke for 258 hours over 196 days.

During these times, the chambers were ventilated for about 35 hours.

Findings revealed that the concentrations of over half of the compounds under scanner were higher in the chronic samples than in the acute.

Researchers also found higher levels of DNA damage caused by the chronic samples.

Third-hand smoke, researchers said, is particularly insidious because it is extremely difficult to get rid of. The gravity of the situation can be gauged from the fact that particles of third-hand smoke can be detected in dust and surfaces of homes even more than two months after smoking in the areas ceased.

There was a 0.4 per cent conversion in human cells within the first hour of exposure, researchers highlighted. This rate increased 10-fold over a three-hour period.

“Given the rapid sorption and persistence of high levels of nicotine on indoor surfaces, including clothing and human skin, our findings indicate that third-hand smoke represents an unappreciated health hazard through dermal exposure, dust inhalation and ingestion,” study’s lead author, Mohamad Sleiman said.

“Ultimately knowledge of the mechanisms by which third-hand smoke exposure increases the chance of disease development in exposed individuals should lead to new strategies for prevention,” researchers wrote.

The findings of the study are published in the science Journal Mutagenesis.