BEWARE OF THIRD-HAND SMOKE
Tobacco toxins linger in the environment long after a cigarette is extinguished.
Ever take a whiff of a smoker's hair
and feel faint from the pungent scent of cigarette smoke? 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. Third-hand smoke is tobacco
smoke contamination that remains after the cigarette has been extinguished.
According to the Jonathan Winickoff's
study at Harvard Cancer Center in Boston, a large number of people, particularly smokers,
have no idea of that
the Third-hand smoke is 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 infant, children
and other people.
'Third-hand smoke' is a relatively new concept but one that have worried
researchers and nonsmokers for several
years. The idea of third-hand smoke has been around for a long time. It's
only recently been given a name and studied.
The level of toxicity in cigarette smoke is just as a trinomial when compared
to other environmental toxins, such as
particles found in automobile exhaust. The following statement is a summary
of Winickoff' explanations about that 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. It is the stuff that remains, after visible or the second-hand smoke
has dissipated from the air. You can't quantify
it, because it depends on the space. In a tiny space like a car, the deposition
is really heavy. Smokers don't see
the smoke going into a person' nose; they think that if they cannot see
it, it's not affecting other people. 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. 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,
that is a poison used to kill mammals. We used
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 68 kilograms. Let's say a baby
weighs seven kilograms. The infant ingests twice the dust [due to faster
respiration and proximity to dusty surfaces].
Effectively, they'll get 20 times the exposure.
Source: PEDIATRICS Vol. 123 No. 1 January 2009
Third-hand smoke' could damage health.
The scientists say residue on clothing, furniture and wallpaper can react
with a common indoor pollutant to generate
dangerous chemicals called tobacco-specific nitrosamines (TSNA).
In the tests, contaminated surface exposed to "high but reasonable"
amounts of the pollutant nitrous acid - emitted
by un-vented gas appliances and in-car exhaust - boosted levels of newly
formed TSNA 10-fold. Substantial traces of
TSNA was also found on the inside surfaces of a truck belonging to a heavy
smoker. The researchers say the third-hand
smoke is an unappreciated health hazard, and suggest a complete ban on
smoking in homes and in vehicles to eliminate
any risk. Nicotine residues from tobacco smoke hang around for weeks or
months.
Source: BBC News 9 February 2010
三次喫煙の危険性
Third-hand smokeを直訳すると「三次喫煙」だが、日本ではほとんど知られていない言葉である。電車に乗っている時に
タバコ臭い人がいませんか。また、喫煙室から出てきた喫煙者がとてもタバコ臭い、そうした経験があると思います。
それが三次喫煙です。喫煙室で喫煙者の衣服にこびりついたタバコの有害物質が喫煙室で出てもなお周囲に放出され、
他人の健康被害を与えます。ホテルの喫煙客室を利用した場合、喫煙者がその場にいなくても三次喫煙の被害に
遭ってしまいます。
喫煙に安全なレベルは存在しません。タバコの火を消した後でも残るタバコ煙の有害物質は残留します。子供たちが
真っ先に、こうした三次喫煙の被害者となるのです。カリフォルニア州バークレーにあるローレンス・バークレー国立研究所
科学者、ララ・グンデルは「火のついたタバコから生成されるニコチンなどの物質は空気中に存在しているのではなく、ものの
表面に吸着している」と述べています。特に注意を要するのは、ニコチンと空気中の亜硝酸が反応して生成される TSNA
（タバコ特異的ニトロソアミン）という強力な発ガン物質なのです。これは空気中に存在するのではなく、タバコの喫煙に
伴って部屋や、ものの表面に付着して層を形成しています。
こうした三次喫煙を防止するには鉄道、自動車、ホテルなど屋内空間での喫煙を禁止するすることしかないのです。
2010年3月執筆 2012年1月加筆
著作権は「禁煙席ネット」主宰 宮本順伯に帰属
★『禁煙席ネット』 サイトへのリンクは自由
The article was revised in January 2012, by Junhaku Miyamoto, M.D.,PhD.
