Anyone walking into a smoker’s abode can tell you that the
traces of tobacco use don’t vanish when a cigarette is
extinguished. Does this so-called thirdhand smoke pose a health
hazard? Researchers at Lawrence Berkeley National Laboratory
found that remnants of cigarette smoke don’t just inertly settle
onto surfaces. Instead the leftover nicotine can react with
nitrous acid vapor, an environmentally common chemical emitted
from gas appliances and vehicles, among other sources. The
reaction produces carcinogenic compounds known as tobacco-
specific nitrosamines (TSNAs). Secondhand smoke itself contains
TSNAs, but the presence of nitrous acid in an environment can
increase their numbers by several times in the hours after
smoking has ceased. And because nicotine can linger on surfaces
for weeks or months, this form of exposure might be even more
persistent than firsthand or secondhand smoke, with the TSNAs
being inhaled, ingested and dermally absorbed into the body.
Children are likely to be the population most