Beware of third-hand smoke, warns study

The latest research on the hazards of smoking initiated by scientists from the Lawrence Berkeley National Laboratory in California, has revealed that the nicotine vapors that release on burning of tobacco get absorbed onto indoor surfaces like walls, floors, carpets, drapes, furniture and clothes.

These further react with nitrous acid released by gas appliances and diesel engines to form carcinogen, a cancer-causing agent known as tobacco-specific nitrosamines, TSNA.

Lara Gundel from the Indoor Environment Department at Berkeley Lab informs, “Smoking outside is better than smoking indoors but nicotine residues will stick to a smoker's skin and clothing. Those residues follow a smoker back inside and get spread everywhere. The biggest risk is to young children.”

“Dermal uptake of the nicotine through a child's skin is likely to occur when the smoker returns and if nitrous acid is in the air, which it usually is, then TSNA will be formed,” she adds.

Study details
The researchers conducted laboratory trails on cigarette smoke and a pickup truck driven by a 45-year-old heavy smoker to find how nicotine reacted when exposed to nitrous acid (HONO).

On analysis, they found that TSNA compound formed rapidly in the presence of nitrous acid. It would be easy to ingest this new compound, they said, calling it "an unappreciated health hazard."

According to the researchers, this nicotine residue that stays behind on indoor surfaces may form into slime-like substance on reaction with HONO, and infants and children were at greater risk from these.

Kamlesh Asotra from the University of California's Tobacco-Related Disease Research Program says, “Nicotine, the addictive substance in tobacco smoke, has until now been considered to be non-toxic in the strictest sense of the term.”

“What we see in this study is that the reactions of residual nicotine with nitrous acid at surface interfaces are a potential cancer hazard, and these results may be just the tip of the iceberg.”

What to do?
The research team feels that the best method of prevention is by implementation of 100 percent ban on smoking in public places and imposing self-restrictions in homes and automobiles.

Hugo Destaillats, co-author of the study, says, “In buildings where substantial smoking has occurred, replacing nicotine-laden furnishings, carpets and wallboard can significantly reduce exposures to third-hand smoking hazards.”

The researchers have also found that using electronic cigarettes does not help either, as these e-cigarettes vaporize nicotine into the air that gets absorbed in the surroundings.

Findings of the present study have been detailed in the Proceedings of the National Academy of Sciences.