Smoking has never been less welcome than it is today, and its risks have never been clearer, but smokers still have enormous difficulty leaving the habit behind. There are several substitutes that help smokers kick the habit, from patches and inhalers to gum and lozenges, but none of them mimic the act of smoking very well, and the habitual part of smoking is as much a part of the problem as the physical addiction to nicotine. To add to the problem, some people simply like to smoke.

Enter the electronic cigarette, also known as the “e-cigarette,” a device that brings smokers closer than any patch or gum to the physical act of smoking. It consists of a cartridge that holds flavored liquid, often containing nicotine, and a battery-powered atomizer that heats the liquid so that it vaporizes. The vapor can then be inhaled. An electronic cigarette is the size and shape of an ordinary cigarette, and most electronic cigarettes are colored in the standard tan and white of filtered cigarettes.

Cartridges are available in a wide range of flavors, with each manufacturer selling proprietary blends that include cherry, chocolate, coffee, vanilla, mint and mixtures that try to duplicate the tastes of popular “analog” cigarettes. They are also sold with the addition of nicotine in varying strengths and with no nicotine at all.

Electronic cigarettes, then, try to mimic their tobacco counterparts as much as possible, from taste to manner of use, but there are significant differences between the two products.

Cigarette smoke contains a great many compounds, in addition to nicotine, that can have detrimental health effects. Electronic cigarettes do not subject the user to this same array of potential dangers.

Cigarette smoke can have adverse effects on people in the smoker’s vicinity who are compelled to inhale some of the smoke that escapes from the burning cigarette and from the smoker. Electronic cigarettes do not appear to produce any meaningful amount of this “second-hand smoke.”

Ordinary cigarettes burn at very high temperatures and careless use can start a fire. Electronic cigarettes share none of this fire risk.

Many people find the smell of cigarettes offensive. Smokers themselves report a reduction in their ability to taste and smell. Neither problem applies electronic cigarettes.

Finally, depending on brand and place of purchase, electronic cigarettes can be less costly than ordinary cigarettes, with manufacturers claiming a saving of more than 50 percent compared to the cost of ordinary cigarettes in some big cities