Cigarette smoke contains carbon monoxide, which displaces the oxygen in your skin, and nicotine, which reduces blood flow, leaving skin dry and discolored.

香烟烟气所含的一氧化碳，置换了皮肤中的氧气，而尼古丁降低了血流量，导致皮肤干燥失色。

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Destaillats's team reckon that NNK is produced when nicotine from tobacco smoke reacts with nitrous acid in the air.

Hugo Destaillates的团队猜想，亚硝胺(NNK)是烟草中的尼古丁和空气中的亚硝酸反应生成的。

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The nicotine in cigarette smoke can not only make your teeth (and the walls of your home) brown, but it's also notorious for staining fingers and nails as well.

香烟中的尼古丁不仅会使你的牙齿以及你家的墙变黄，而且还会使你的手指和指甲变色。

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But she says there is much evidence that nicotine in tobacco smoke affects the nervous system, and child development and behavior.

VOA: special.2009.01.13

Chantix works on nicotine receptors in the brain to reduce the urge to smoke.

VOA: special.2010.03.09

But, through research in Southampton laboratories, the firm is also attempting to refine processing techniques such that levels of nicotine and, in particular, tar in cigarette smoke are reduced.

BBC: BAT targets 'low-risk' cigarettes

Components of tobacco smoke such as carbon monoxide, nicotine, benzene and small particles can easily be measured in the air of a smoker's home or workplace.

CNN: Is secondhand smoke really that risky?

The product, in various forms, essentially supplies the drug smokers crave nicotine without the toxic, deadly smoke.

FORBES: The EU's New Tobacco Directive: Protecting Cigarette Markets, Killing Smokers