Health experts say secondhand smoke is 6 to 12 times more toxic than the smoke directly inhaled by a smoker. And now the experts are warning that third-hand smoke (THS), the invisible, toxic gases and particles that hang around on thinss like clothes, furniture, hair and skin long after a cigarette or cigar has been put out, may be even more harmful.
The longer nicotine toxins linger on persons or objects, the more time they have to react with common indoor pollutants, such as nitrous acid, to create new and dangerous carcinogenic chemicals that can be inhaled or ingested.
Hugo Destaillats, a chemist with the Indoor Environment Department of Berkeley Lab’s Environmental Energy Technologies Division, had this to say about the resulting carcinogenic chemicals: “The burning of tobacco releases nicotine in the form of a vapor that adsorbs (gas molecules accumulating) strongly onto indoor surfaces, such as walls, floors, carpeting, drapes and furniture. Nicotine can persist on those materials for days, weeks and even months.
“Our study shows that when this residual nicotine reacts with ambient nitrous acid, it forms carcinogenic tobacco-specific nitrosamines, or TSNAs.
“TSNAs are among the most broadly acting and potent carcinogens present in unburned tobacco and tobacco smoke.”
Destaillats and the 5 co-authors of the Berkeley Lab study based tests on cellulose as a model indoor material exposed to smoke and found that TSNAs increase rapidly in short periods of time. Levels of newly formed TSNAs on the cellulose surfaces were 10 times higher after only 3 hours than when they’d been originally deposited.
The team also collected measurements of TSNAs on the interior of a smoker’s truck. In addition to the TSNAs, the measurements showed substantial levels of the nitrosamine known as NNA along with 2 other potent carcinogens: NNN and NNK.
In another study regarding smoking in a vehicle, Dr Jonathan Winickoff, associate professor of pediatrics at Harvard Medical School, told Best Health Magazine, “And don’t even think about allowing smoking in the car, even with a window open. The smaller the space, the more intense the exposure to toxins.”
Dr Winickoff believes that children are more vulnerable to the effects of THS, pointing out that though children may be only one-tenth the size of adults, they ingest twice the amount of toxic air particles that adults do, thus giving them 20 times the dose.
Dr Vinayak Jha, Associate Pulmonologist at George Washington Medical Faculty, concurs with Winickoff. He says, “(Children are) crawling along floors, they’re ingesting dust and they’re putting other objects in their mouths which could be contaminated with third-hand smoke.”
Smoking outdoors is not much of an improvement to smoking indoors. Lara Gundel of Berkeley labs says, “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 TSNAs will be forming.”
Berkeley lab’s James Pankow said the results of the study should raise concerns about the supposed safety of “e-cigarettes.” Because no flame or ignition or tobacco or combustion is involved, these electronic cigarettes are not restricted by anti-smoking laws.
Packow 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.”
SOURCES: Mayo Clinic Lawrence Berkeley National Laboratory, February 8, 2010 Global Advisors Smoke-free Policy (GASP), September 2012 WJLA ABC News transcript, March 2013 Best Health Magazine (Canada) About.com Lung Cancer, September 01, 2012
Berkeley Lab study published in Proceedings of the National Academy of Sciences (PNAS)
Berkeley Lab study funded by University of California’s Tobacco-Related Disease Research Program
Coming up: Avoiding and removing Third-hand Smoke