"Time-course measurements revealed fast TSNA formation, up to 0.4 percent conversion of nicotine within the first hour," says lead author Sleiman. "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."
Since the most likely human exposure to these TSNAs is through either inhalation of dust or the contact of skin with carpet or clothes, third-hand smoke would seem to pose the greatest hazard to infants and toddlers. The study's findings indicate that opening a window or deploying a fan to ventilate the room while a cigarette burns does not eliminate the hazard of third-hand smoke. Smoking outdoors is not much of an improvement, as co-author Gundel explains.
"Smoking outside is better than smoking indoors but nicotine residues will stick to a smoker's skin and clothing," she says. "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 TSNAs will be formed."
The dangers of mainstream and secondhand tobacco smoke have been well documented as a cause of cancer, cardiovascular disease and st
|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory