Battery-powered cigarettes convert dissolved nicotine concentrate into vapour, which can then be inhaled without many of the toxic by-products associated with burning tobacco.
The electronic cigarette has three basic components: a chamber, an atomiser and a battery. The chamber contains nicotine and flavourings in a carrier liquid, such as propylene glycol. A wick, made from metal mesh or silica, draws the liquid into the atomiser, where it is heated by a battery-powered coil until it vaporises. The vapour is then inhaled and exhaled like tobacco smoke.
Electronic cigarettes are designed to simulate the feel, taste and nicotine hit of cigarettes, but their safety is debated. In many countries their manufacture and sale is unregulated, resulting in variation in their chemical contents. Their usefulness as nicotine replacement therapy is also largely unknown and the World Health Organization does not condone their use.