Per: http://health.yahoo.com/news/afp/healthustobacco_20100209102313.html
By AFP - Tue Feb 9, 2:20 AM PST
WASHINGTON (AFP) - You know smoking is bad for you. You know inhaling someone else's smoke is bad for you. Now a US study says third-hand smoke -- tobacco residue clinging to surfaces -- is also bad for you
When a cigarette burns, nicotine is released in the form of a vapor that collects and condenses on indoor surfaces such as walls, carpeting, drapes and furniture, where it can linger for months, said the study, which was published in the Proceedings of the National Academy of Sciences (PNAS).
"Our study shows that when this residual nicotine reacts with ambient nitrous acid it forms carcinogenic tobacco-specific nitrosamines, or TSNAs," said Hugo Destaillats, a corresponding author of the study.