The dangers of smoking tobacco have been well documented since the
1960s. For years, health experts have also warned about the dangers of
second-hand smoke - breathing in other people's cigarette smoke. Now,
some researchers are sounding the alarm over what they call "third-hand
Third-hand smoke is the tobacco contamination that
remains after a cigarette is extinguished. Dr. Jonathan Winickoff of
Harvard University has been studying it.
"What happens is, the
smoker goes outside to smoke their cigarette. Then they come back
inside. They're still contaminated with smoke," he says. "They offgas
[give off] the smoke toxins from their clothes. They also exhale
residual particulates into their home space so that there is still
contamination inside the home that is detectable."
says this third-hand smoke - the often-smelly residue that's left on
carpets, furniture, clothing and so on - contains all the nasty toxic
chemical material that's in cigarette smoke.
He says it includes "some of the most toxic compounds known to humankind."
we're talking about hydrogen cyanide, which is used in chemical
weapons; carbon monoxide, car exhaust; ammonia, those are household
cleaners; arsenic, which is used as a pesticide to kill mammals; lead;
chromium, which is used to make steel; and, believe it or not, polonium
210, which is a highly radioactive and deadly compound."
Winickoff says that third-hand smoke can be harmful to anyone, but he says children are most at risk.
have a higher metabolic rate than adults. They breathe faster. And they
have less body mass. So for the same exposure, they'll get more of it
into them, and they are more susceptible. Their susceptibility really
stems from the fact that their tissues are developing. And their
brains, especially, are developing."
In the January issue of
the journal Pediatrics,
Winickoff reports on a survey that found parents are more likely to ban
smoking at home if they believe third-hand smoke is going to harm their
children. As a result, he says it's important to get the word out.
the parent smells the smoke, then it's important for the parents to
realize that it's really there. So where a parent smells that exposure,
it's important that they remove the child from that space. For smokers,
I think the message is really clear also: If you really want to protect
non-smokers and children, then the best thing to do is continue on your
process of quitting smoking."
Winickoff is also a practicing
pediatrician. He says he got interested in the subject of third-hand
smoke about 10 years ago when he was treating children for asthma and
smelled tobacco smoke on their parents.