Researchers warn cigarette dangers
may be even more far-reaching
Ever take a whiff of a smoker's hair and feel faint from the pungent
scent of cigarette smoke? Or perhaps you have
stepped into an elevator and wondered why it smells like someone has lit up
when there is not a smoker in sight. Welcome to the world of
"Third-hand smoke is tobacco smoke contamination that remains
after the cigarette has been extinguished," says Jonathan Winickoff, a
pediatrician at the Dana–Farber/Harvard Cancer Center in Boston and author of a
study on the new phenomenon published in the journal Pediatrics. According to the study, a
large number of people, particularly smokers, have no idea that third-hand
smoke—the cocktail of toxins that linger in carpets, sofas, clothes and other
materials hours or even days after a cigarette is put out—is a health hazard
for infants and children. Of the 1,500 smokers and nonsmokers Winickoff
surveyed, the vast majority agreed that second-hand smoke is dangerous. But when
asked whether they agreed with the statement, "Breathing air in a room
today where people smoked yesterday can harm the health of infants and
children," only 65 percent of nonsmokers and 43 percent of smokers
"Third-hand smoke," a term coined by Winickoff's research team, is a
relatively new concept but one that has worried researchers and nonsmokers for
several years. "The third-hand smoke idea—concern over that—has been
around for a long time. It's only recently been given a name and studied,"
says Stanton Glantz, director of the Center for Tobacco Control Research and
Education at the University of California, San Francisco. "The level of
toxicity in cigarette smoke is just astronomical when
compared to other environmental toxins [such as particles
found in automobile exhaust]," he adds, but
notes that he is not aware of any studies directly linking third-hand smoke to
disease [as opposed to second-hand smoke, which has been
associated with disease].
ScientificAmerican.com asked Winickoff to explain
exactly what third-hand smoke is and why it poses a public health risk.
How exactly do you distinguish between second-
and third- hand smoke?
Third-hand smoke refers to the tobacco toxins that build up over time—one
cigarette will coat the surface of a certain room [a second cigarette will add
another coat, and so on]. The third-hand smoke is the stuff that remains [after
visible or "second-hand smoke" has dissipated from the air]…. You
can't really quantify it, because it depends on the space…. In a tiny space
like a car the deposition is really heavy…. Smokers [may] smoke in another room
or turn on a fan. They don't see the smoke going into a child's nose; they
think that if they cannot see it, it's not affecting [their children].
Smokers themselves are also contaminated…smokers actually emit toxins [from
clothing and hair].
Why is third-hand smoke dangerous?
The 2006 surgeon general's report says there is
no risk-free level of tobacco exposure…. There are 250 poisonous toxins found
in cigarette smoke. One such substance is lead. Very good studies show that tiny
levels of exposure are associated with diminished IQ.
What do you consider the most dangerous
compound in cigarette smoke?
I would say cyanide, which is used in chemical weapons. It actually interferes
with the release of oxygen to tissues. It competitively binds to hemoglobin [meaning it competes with oxygen
for binding sites on the blood's oxygen-carrying molecule, hemoglobin].
Basically people with cyanide poison turn blue…. [And] arsenic, that is a poison used to kill mammals. We [used to] use it to kill rats.
And there it is in cigarette smoke.
Why are the risks associated with exposure to
third-hand smoke different for children and adults?
The developing brain is uniquely susceptible to extremely low levels of toxins.
Remember how we talked about the layers of toxin deposits on surfaces? Who gets
exposure to those surfaces? Babies and children are closer to [surfaces such as
floors]. They tend to touch or even mouth [put their mouths to] the
contaminated surfaces. Imagine a teething infant.
Children ingest twice the amount of dust that grown-ups do. Let's say a
grown-up weighs 150 pounds [68 kilograms]. Let's say a baby weighs 15 pounds
[seven kilograms]. The infant ingests twice the dust [due to faster respiration
and proximity to dusty surfaces]. Effectively, they'll get 20 times the
Studies in rats suggest that tobacco toxin exposure is the leading cause of sudden infant death syndrome (SIDS). We
think it is [caused by] respiratory suppression.
What types of places or materials harbor the
greatest amount of third-hand smoke?
Anywhere you see an enclosed space you should watch out for [it].
By introducing the phrase "third-hand
smoke" in your research, what do you hope to accomplish?
This study points to the need for every smoker to try to quit. That's the only way to completely
protect their children…. Really, I think that what this says is that we need to
have sympathy for smokers and help them quit smoking…. [And also] that the
introduction of this concept will lead to more smoke-free spaces in…public