Also known as e-cigarettes, e-cigs, electronic nicotine delivery systems, vaporizer cigarettes, and vape pens, they are marketed as a way to stop or cut down on smoking.
E-cigarettes have been taken up by millions around the world since they first appeared on the Chinese market in 2004.
By 2014, around 3.7 percent of adults in the United States (U.S) were using them, and 12.6 percent had tried them. "Vaping" is now the most popular form of tobacco use among teenagers in the U.S. E-cigarette use rose by 900 percent among high school students from 2011 to 2015.
However, a growing body of research suggests that vaping may be hazardous, and in 2016, the U.S. Food and Drug Administration (FDA) started to enforce rules about the sales, marketing, and production of these products.
Here are some key points about e-cigarettes. More detail is in the main article.
- E-cigarettes aim to resemble cigarettes, but without burning tobacco.
- They are sold as aids to reduce or quit smoking, and some people find them helpful for this.
- However, research shows that they may have a negative impact on health.
- Health authorities are trying to tighten up regulations to discourage young people from using e-cigarettes.
What are e-cigarettes?

Vaping: Is it really safer than smoking?
An e-cigarette is a long tube that usually resembles a cigarette, a cigar, a pipe, or a pen. Most are reusable, with replaceable and refillable cartridges, but some are disposable.
The first patent for a "smokeless, non-tobacco cigarette" was requested by Herbert A. Gilbert in 1963, but the current device did not appear until 2003.
The e-cigarette as we know it was invented by Hon Lik, a Chinese pharmacist, working for Golden Dragon Holdings, now known as Ruyan. The company started exporting into major markets in 2005 to 2006. There are now over 460 different brands on the market.
How they work
Most e-cigarettes have:
- a mouthpiece, or cartridge
- a heating element
- a rechargeable battery
- electronic circuits
As the user sucks on the mouthpiece, a sensor activates a heating element that vaporizes a flavored, liquid solution held in the mouthpiece. The person then "vapes," or inhales, the aerosol solution.
The nicotine content varies from zero to "extra-high," or 24 to 36 milligrams (mg) per milliliter (ml).
The mouthpiece is a cartridge that is fixed to the end of a tube. A small plastic cup within the mouthpiece holds an absorbent material drenched in the liquid solution.The cartridge can either be refilled or replaced with another pre-filled cartridge when necessary.
The atomizer is a heating element that heats the liquid, causing it to vaporize. The solution can then be breathed in, or inhaled.
The battery powers the heating element. This is normally a rechargeable, lithium-ion battery.
The sensor activates the heater when the user sucks on the device. An LED may show when it is activated.
The solution, also known as e-liquid or e-juice, is made by extracting nicotine from tobacco and mixing it with a base, usually propylene glycol, and flavoring. Propylene glycol is used in inhalers, for example, for asthma. There is a wide range of flavors to choose from, with names such as traditional, watermelon, menthol, and lava flow.
Some flavors, such as a combination of tobacco and menthol, try to resemble traditional cigarettes. A number of them claim to mimic specific brands.
Benefits

The e-cigarette may be less hazardous than tobacco for existing smokers, but it appears to bring dangers of its own.
E-cigarettes claim to bypass many of the health risks of tobacco smoking, and to offer a more healthful alternative to cigarettes and other conventional forms of nicotine intake.
Some studies have found that using e-cigarettes can help some smokers quit.
Others suggest they offer "modest" benefits for those who want to quit smoking, but "good potential" for those who are cutting down.
However, the device is not only aimed at older people seeking to quit smoking, and while e-cigarettes may help some people quit smoking, there is growing evidence that vaping may be harmful in some cases.
Marketing the activity as cool and safe, and offering a variety of flavors, manufacturers are keen to attract teens and adolescents, who often believe vaping is less hazardous than smoking.
However, that is not necessarily true, and in 2016, the Surgeon General declared e-cigarette use a "significant public health concern."
Risks
Here are 10 reasons why the authorities are concerned:
- Most e-cigarettes contain nicotine, which is addictive and triggers changes in the adolescent brain. It is hazardous during pregancy as it can affect fetal development.
- The aerosol contains solvents, flavorings, and toxicants, which the Surgeon General describes as either "harmful" or "potentially harmful."
- E-cigarettes expose the lungs to different substances. One of these is dicetyl, which can cause "popcorn lung," a severe and irreversible lung disease.
- Potentially fatal poisoning has resulted from accidentally swallowing and from inhaling c-cigarette liquid.
- People who seek to quit smoking will stop using conventional and medically monitored methods of doing so.
- Those who use or who have used e-cigarettes are be less likely to stop smoking altogether.
- Teens who use e-cigarette products are more likely to start using regular tobacco as well.
- Continued use of nicotine can make other drugs, such as cocaine, more pleasurable.
- The flavorings, the marketing, and the concept that it is not harmful all tempt teenagers to start vaping. There is concern that this increases the chance that they will smoke conventional cigarettes later.
- Second-hand smoking is not eliminated by vaping, as vaping releases carcinogenic emissions.
In addition, experimental use of vaping materials may put teens at higher risk. The National Institute on Drug Abuse (NIDA) point to the practice of "dripping," which involves inhaling solutions that are dripped directly onto the heater coil. Reasons include "to produce a stronger throat hit."
Takeaway

"E-juice" contains solvents, flavorings, and varying amounts of nicotine.
Even if vaping can help people quit smoking, it has not been certified as safe and effective by the FDA, and there is no evidence that it works in the long term.
According to NIDA, "Research so far suggests that e-cigarettes might be less harmful than cigarettes when people who regularly smoke switch to them as a complete replacement."
However, they add, "nicotine in any form is a highly addictive drug."
The Surgeon General's report calls for action to reduce the risk of vaping.
"Actions could include incorporating e-cigarettes into smokefree policies, preventing access to e-cigarettes by youth, price and tax policies, retail licensure, regulation of e-cigarette marketing likely to attract youth, and educational initiatives targeting youth and young adults."
U.S. Department of Health and Human Services
In 2016, the FDA made e-cigarettes subject to the same rules as tobacco products. One result of this is that purchasers must be at least 18 years of age.
The American Academy of Pediatrics (AAP) strongly recommend that the minimum age to purchase any tobacco product, including e-cigarettes, be raised to 21 years in all states.
Nine states have already banned e-cigarette use in the same places where smoking is not allowed, and there is a growing call for vaping regulations to be stricter.
E-cigarettes are a tobacco product, and no tobacco use is safe. Until we know more, it is probably best to use them with caution.