An electronic cigarette, or e-cigarette, is an electrical device that simulates the act of tobacco smoking by producing aninhaled vapor bearing the physical sensation, appearance, and often the flavor (with or without nicotine content) of inhaled tobacco smoke, without its odor or, ostensibly, its health risks. The device uses heat (or in some cases, ultrasonics) to vaporize a propylene glycol- or glycerin-based liquid solution into an aerosol mist, similar to the way a nebulizer or humidifier vaporizes solutions for inhalation.
The device's components usually include a small liquid reservoir, a heating element, and a power source, which may be abattery or a wired USB adapter. Most electronic cigarettes are portable, self-contained cylindrical devices in varying sizes, and many are designed to outwardly resemble traditional cigarettes. Most are also reusable, with replaceable and refillable components, though some models are disposable. Liquids that produce vapor for electronic cigarettes are available in many different flavor varieties and nicotine concentrations, including nicotine-free versions.
The primary stated use of the electronic cigarette is an alternative to tobacco smoking, or a smoking cessation device: It endeavors to deliver the experience of smoking without the adverse health effects usually associated with tobacco smoke, or to at least greatly reduce those risks.
The possible benefits or adverse effects of electronic cigarette use are a subject of disagreement among different health organizations and researchers. Controlled studies of electronic cigarettes are scarce due to their relatively recent invention and subsequent rapid growth in popularity. Laws governing the use and sale of electronic cigarettes, as well as the accompanying liquid solutions, currently vary widely, with pending legislation and ongoing debate in many regions. Concerns have been raised by anti-smoking groups that use of the device still might carry health risks and that it could appeal to non-smokers, especially children, due to its novelty, flavorings, and possibly overstated claims of safety.
The modern electronic cigarette's design was devised by Chinese pharmacist Hon Lik in 2003, though the earliest known description of its concept was authored by Herbert A. Gilbert in 1963.
