These products are used by cigarette smokers as a substitute for the experience of smoking tobacco. There is no combustion so the user inhales vapour, not smoke and, although the nicotine is derived from tobacco, e-cigarettes contain no actual tobacco.
The aerosol is generated by an electric heating element which is activated manually or when the user draws air through the device. This vaporizes a liquid formulation, often referred to as ‘e-juice’ or ‘e-liquid’, and the vapour then condenses to form an aerosol. This formulation is held in a reservoir, often absorbed onto a foam material, and typically contains nicotine, propylene glycol and/or glycerol and flavourings. Commonly, a coloured LED at the end is lit when the device is puffed.
There are many designs, many with cigarette formats with various lengths and circumferences, but devices with completely different shapes are also available. Most formats are available as one-, two- or three- piece products. Two-piece products consist of a battery and a cartomizer (comprising a cartridge and atomizer); in three-piece products the cartridge and atomizer are separate. The devices may be disposable or reusable, with rechargeable batteries and refillable cartridges or reservoirs.
A range of e-liquid formulations is available, with nicotine concentrations from 0 to 5%, and with different flavours or unflavoured.
Some e-cigarettes can be configured by users to meet individual user preferences. This can be achieved through selecting a liquid with a preferred flavour or nicotine concentration and/or a device modification such as increased heating, more powerful battery or variable voltage controller or larger e-liquid reservoir.
Unlike conventional cigarettes, e-cigarettes do not contain tobacco so do not either burn tobacco nor produce tobacco smoke. The scientific community widely agrees it is the toxicants in tobacco and tobacco smoke that cause the majority of tobacco-related diseases. However, e-cigarettes usually contain nicotine, which is addictive and, at high concentrations, can be toxic. Nicotine is inhaled in the aerosol and deposited in the respiratory tract. Other toxic substances have been identified in the aerosols of some e-cigarette products, but usually in much smaller quantities than are found in tobacco smoke.
Using an e-cigarette is sometimes known as ‘vaping’, and the user as a ‘vaper’ (analogous to ‘smoking’ and ‘smoker’).