How Electronic Cigarettes Work

Lighting a traditional cigarette causes the tobacco to burn, releasing smoke that contains nicotine. The user breathes in the smoke to deliver nicotine to the lungs. An electronic cigarette doesn't rely on this process of combustion. Instead, it heats a nicotine liquid and converts the liquid to a vapor, or mist, that the user inhales. Depending on the e-cigarette, the user may simply inhale from the cartridge to begin the vaporization process, though some devices have a manual switch that activates the vaporizer inside.

An e-cigarette has three main parts:

The lithium battery powers the e-cigarette and can be charged using a charger similar to those used for cell phone batteries. The charged battery is connected to the vaporization chamber, a hollow tube that contains electronic controls and an atomizer -- the component that creates the vapor. Before the user activates the device, he or she attaches a cartridge containing nicotine liquid to the vaporization chamber. The tip of the cartridge serves as the e-cigarette's mouthpiece.

E-cigarette users inhale the way they would with a regular cigarette. This inhalation activates the atomizer to heat the liquid in the cartridge and convert the liquid to a vapor. Inhaling this vapor through the mouthpiece delivers nicotine to the lungs, and the user exhales vapor that looks much like a cloud of cigarette smoke.

Fans of e-cigarettes say they enjoy many of the same sensations as tobacco smokers -- holding the device in their hand, inhaling and exhaling. Many e-cigarettes have a light-emitting diode (LED) on the end that lights up when the user inhales, simulating flame. (Artificial flame is the only safe kind when using an e-cigarette -- trying to light the device could cause the battery to ignite and explode.)

The liquid or "smoke juice" that fills the cartridges is usually propylene glycol, an additive that the FDA has approved for use in food. (Fog machines that create a smoky atmosphere at stage shows also use propylene glycol.) Consumers can buy cartridges containing different amounts of nicotine, or no nicotine at all. Manufacturers usually add flavorings to the liquid. Options range from tobacco and menthol flavor to mint, chocolate, coffee, apple, cherry and caramel.

E-cigarette companies sell their products in retail stores, but also, increasingly, online. A wide array of models and brands are available. Some mimic the appearance of tobacco cigarettes, while others look like cigars, pipes and even pens. Prices vary, ranging from $40 to $120 for a starter kit, which usually includes a charger and a few cartridges along with the e-cigarette. Cartridges typically last about as long as a pack of 20 tobacco cigarettes and sell for about $10 each. Consumers also can purchase bottles of e-liquid and refill the cartridges themselves. This reduces the cost of use, generally making e-cigarettes cheaper to use than tobacco cigarettes.

But even if they're affordable and fun to use, are e-cigarettes safe? Some health experts are concerned about marketers promoting them as a healthier alternative to tobacco. So before you trade in your pack of smokes for the electronic version, read on as we fill you in on the potential health risks of e-cigarettes.

Quality control is one of the main issues health experts have with e-cigarettes. They argue that manufacturers may not disclose all of the chemical ingredients used in their products. This means it may be impossible for users to know exactly what they're consuming. There is also not much known about the short- or long-term health effects of exposure to nicotine vapor.

The U.S. Food and Drug Administration (FDA) conducted a small study in 2009 to analyze a sample of nicotine cartridges from two manufacturers. The results showed that the amount of nicotine delivered did not always match the amount stated on the label. The study also revealed that some cartridges labeled nicotine-free in fact contained nicotine. And cancer-causing compounds found in tobacco were also found in some e-cigarette cartridges, along with other toxins. One of the toxins found was diethylene glycol, a toxic chemical used in antifreeze. [source: FDA].

Despite these findings, electronic cigarette manufacturers claim that their products may have the potential to improve the health and lives of people addicted to nicotine. But many health experts say e-cigarette makers haven't conducted the research needed to back up their claims. The World Health Organization (WHO), for example, says there is not enough evidence to show that e-cigarettes are safe.

Health experts are also concerned about companies marketing e-cigarettes as a way to quit smoking. Nicotine replacement therapy (NRT) products like the nicotine patch or gum have been tested for their safety and effectiveness as smoking cessation aids. E-cigarettes have not. Some experts have expressed concern that marketers' claims -- or positive word-of-mouth from e-cig users -- may convince people to use e-cigarettes to try to stop smoking, instead of a method that has been proven effective.

Another question is whether nonsmokers will be attracted by the novelty or the perceived safety of e-cigarettes and take up the habit, thus becoming addicted to nicotine. This is especially important where younger consumers are concerned -- the candy-like flavors may particularly appeal to children and adolescents. And because e-cigarettes are sold online, young people may have easy access -- most companies don't check or confirm the age of their Internet customers.

While e-cigarettes may help consumers avoid many of the health risks of smoking tobacco, they still give users a dose of an addictive substance. Regulatory authorities are struggling to classify electronic cigarettes and introduce the right controls. If e-cigarettes continue to gain popularity, they may become a common sight in restaurants, movie theaters, offices and other venues. Is that a good thing for the public? On the next page, we'll look at a few key issues that e-cigs raise about health, safety and personal freedom.

One of the problems of regulating e-cigarettes is deciding how to classify them. Are they similar enough to tobacco cigarettes to be regulated in the same way? Or are they not cigarettes at all but drug-delivery devices like nicotine patches or gum? Because they don't fit easily into either category, e-cigarettes may require a new set of regulations.

Many people want to know if they can use electronic cigarettes in places that restrict tobacco smoking. Manufacturers and e-cigarette users argue that because the vapor presents no health risks and no offensive odor, e-cigarettes should be permitted everywhere.

E-cig opponents argue that allowing e-cigarette use everywhere may discourage people from cutting back or quitting smoking by making it easier and more socially acceptable to get a nicotine fix. Inconveniences like shivering outside in the cold to enjoy a smoke may actually contribute to some smokers' desires to quit. And until the vapor that e-cigarettes emit is proven safe, harmful effects from secondhand vapor can't be ruled out.

Individual countries and states have adopted a wide range of rules governing e-cigarettes. Australia, Canada and Hong Kong have banned e-cigarette marketing and sale. In the United Kingdom, e-cigarettes marketed as a smoking-cessation aid must be licensed and regulated as a medicine, but their use as a recreational smoking alternative is unrestricted. Brazil regulates e-cigarettes as tobacco products. In the United States, the FDA has confiscated e-cigarette shipments coming into the country on the grounds that they are unapproved drug-delivery devices. Two e-cigarette manufacturers took the FDA to court to oppose this action and won [source: U.S. District Court for District of Columbia].

Regulations will continue to evolve as electronic cigarettes grow in popularity and experts seek to gain reliable information about them. In the meantime, users around the world are relishing the experience of smoking cigarettes without the smoke.