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發佈日期： 2014-05-29

E-Cigarettes Deliver a Puff of Carcinogens
Electronic cigarettes appear to be safer than cigarettes for one simple reason: People don’t light up and smoke them.
With the e-cigarettes, there is no burning tobacco to produce myriad new chemicals, including some 60 carcinogens.
But new research suggests some popular e-cigarettes get so hot they can produce a handful of the carcinogens found in cigarettes and at similar levels.
A study to be published this month in the journal Nicotine and Tobacco Research found the high-power e-cigarettes known as tank systems produce formaldehyde, a known carcinogen, along with the nicotine-laced vapor that their users inhale. The toxin is formed when liquid nicotine and other e-cigarette ingredients are subjected to high temperatures. A second study points to similar findings.
The long-term effects of inhaling nicotine vapor are unclear, but there is no evidence it causes cancer or heart disease. Many researchers say e-cigarettes will turn out to be much safer than cigarettes.
Both studies focused on tank systems, fast-growing members of the e-cigarette family. Unlike disposable e-cigarettes, which tend to mimic the look and feel of conventional smokes, tank systems tend to be larger devices heated with batteries that can vary in voltage . Users fill them with liquid nicotine, or e-liquid, and the devices vaporize that fluid quickly, producing thick plumes and a big nicotine kick. Maciej L.
Goniewicz of the Roswell Park Cancer Institute in Buffalo, New York, who led the first study, said people using the systems “want more nicotine, but the problem is they’re also getting more toxicants.”
The second study focus ed on how people use the devices to create more potent vapor by dripping fluid onto the heating element . The e-liquid heats with such intensity that formaldehyde and related toxins “approach the concentration in cigarettes,” said Dr. Alan Shihadeh of American University in Beirut, who led the research.
Both studies show intense heat can change the composition of e-liquids, creating new chemicals. The researchers said the chemical reactions apply not only to the liquid nicotine, but also to two other crucial ingredients in most e-liquids: vegetable glycerin and propylene glycol.
The Roswell study found that when battery voltage increased to 4.8 volts from 3.2 volts, toxin levels increased markedly.
“This finding suggests that in certain conditions, E.C.s might expose their users to the same or even higher levels of carcinogenic formaldehyde as tobacco smoke,” the Roswell study says.
Traditional cigarettes create dozens of carcinogens, said Prue Talbot of the University of California, Riverside . E-cigarettes do not tend to generate enough heat to create combustion, a big reason health officials predict they will prove less harmful than cigarettes.
Dr. Shihadeh said, “If I was in a torture chamber and you said I had to puff on something, I’d choose an e-cigarette over a regular cigarette.”
The new tank systems are exploding in popularity and reshaping the market , said Bonnie Herzog, an industry analyst . She expects sales in the United States “in excess of $2 billion” a year.
Experts say tank systems appeal to young people who like products that can be customized with flavors and power, and are comfortable with fast-changing technology.
“Technology is way ahead of the science,” Dr. Shihadeh said. “We’re creating this stuff, and we don’t understand the implications.”
中譯
電子菸顯得比一般香菸安全的原因很簡單：人們不必點燃、吸食。
電子菸不燃燒煙草，不會產生多種新的化學物質，其中包括大約60種致癌物。
然而最新研究顯示，部分受歡迎的電子菸會熱到可能產生一般香菸釋出的多種致癌物質，濃度也類似。
根據即將發表在本月份 「尼古丁與菸草研究」期刊的一項研究報告，有菸液槽的強力電子菸除了釋出使用者吸入的含尼古丁煙霧，還會產生已知致癌物甲醛。液態尼古丁與電子菸的其他成分接觸高溫就會產生毒素。另一研究也有類似發現。
吸入尼古丁煙霧長期影響仍然不明，但並無證據顯示會引起癌症或心臟病。許多研究人員說，電子菸會比一般香菸安全得多。
兩項研究都以菸液槽型電子菸為重點。它是電子菸家族中成長快速的成員。不同於模仿傳統香菸形狀與感覺的拋棄式電子菸，菸液槽型是比較大的裝置，以伏特數不同的電池加熱。使用者填入尼古丁液態，裝置很快便讓它蒸發，產生濃厚的煙霧及強烈的尼古丁興奮感。
紐約州水牛城羅斯威爾公園癌症研究所的戈涅維契主持第一項研究。他說，使用這種裝置的人想「獲得更多尼古丁。問題是，他們同時也吸入更多毒素」。
第二項研究的重點是，瞭解人們如何把液體滴到加熱組件上之後，創造更有力的煙霧。主持研究的貝魯特美利堅大學謝哈迪赫博士說，菸液高溫加熱使甲醛與相關毒素「濃度接近一般香菸」。
兩項研究都顯示，高熱可能改變菸液成分，產生新的化學物質。研究人員說，產生化學反應的不只是液態尼古丁，還有多數菸液的另二種重要成分：植物甘油與丙二醇。
羅斯威爾研究所的研究還發現，如果電池電壓由3.2伏特提高至4.8伏特，毒素濃度會大增。報告中說：「這項發現意味，某些情況下，電子菸使用者可能接觸濃度與一般香菸相同，甚至更高的致癌物甲醛。」
河濱加州大學的陶伯特說，傳統香菸會釋出數十種致癌物。電子菸產生的熱通常不至於引起燃燒。衛生官員據此認為，電子菸的危害性低於一般香菸。
謝哈迪赫說：「如果我被送進刑求室，你說我必須吸吐什麼，我一定選電子菸，不要一般香菸。」
業界分析師芭妮‧赫佐格說，菸液槽型電子菸突然爆紅，而且正在改變市場。她認為美國市場年銷售額會「超過20億美元」。
專家說，菸液槽型電子菸對喜歡口味與強度可客製化的產品、而且樂見科技推陳出新的年輕人，特具吸引力。
謝哈迪赫說：「科技產品遠遠走在科學前面。我們創造這種東西，卻不知箇中意義。」