Electronic cigarette

A first generation electronic cigarette resembling a tobacco cigarette.

A later-generation PV.

An electronic cigarette (e-cig or e-cigarette), personal vaporizer (PV) or electronic nicotine delivery system (ENDS) is a battery-powered vaporizer that feels like tobacco smoking. The user inhales an aerosol, commonly called vapor, rather than cigarette smoke. In general, e-cigarettes have a heating element that atomizes a liquid solution known as e-liquid. E-cigarettes are generally cylindrical, with many variations. There are disposable or reusable versions. E-liquids usually contain a mixture of propylene glycol, glycerin, nicotine, and flavorings. E-liquids are also available without propylene glycol, without nicotine, or without flavors.

The benefits and health risks of electronic cigarettes are uncertain. One review found limited evidence of a benefit as a smoking cessation aid, but there is no evidence they are better than regulated medication for quitting smoking. Their usefulness in tobacco harm reduction is unclear. One review found their safety risk is similar to that of smokeless tobacco. Another found United States Food and Drug Administration (FDA)-approved products, such as nicotine inhalers, are probably safer than e-cigarettes.

Limited evidence suggests e-cigarettes are safer than traditional cigarettes. People who do not already smoke may become addicted to them. There is no evidence e-cigarettes are regularly used by those who have never smoked. E-cigarette use may delay or deter quitting smoking. E-cigarettes create vapor that consists of ultrafine particles. The vapor contains similar chemicals to the e-liquid, together with tiny amounts of toxicants and heavy metals. E-cigarette vapor contains fewer toxic substances than cigarette smoke, and is likely to be less harmful than traditional cigarettes to users and bystanders. No serious adverse effects from e-cigarettes have been reported in trials. Less serious adverse effects include throat and mouth inflammation, vomiting, nausea, and cough. The long-term effects of e-cigarette use are unknown.

Use has risen, with up to 10% of American high school students having used them at least once as of 2012, and around 3.4% of American adults as of 2011. In the United Kingdom user numbers have increased from 700,000 in 2012 to 2.1 million in 2013. About 60% of UK users are smokers and most of the rest are ex-smokers. Most e-cigarette users still smoke traditional cigarettes. Most peoples' reason for using e-cigarettes is related to quitting, with a considerable proportion using them recreationally. The modern e-cigarette arose from a 2003 invention by Hon Lik in China and as of 2014 most devices are made there. E-cigarette brands have increased their advertising, using marketing techniques like those used to sell cigarettes in the 1950s and 1960s. Because of the potential relationship with tobacco laws and medical drug policies, electronic cigarette legislation is being debated in many countries. The European Parliament passed regulations in February 2014 standardizing liquids and personal vaporizers, listing ingredients, and child-proofing liquid containers. The US FDA published proposed regulations in April 2014 with some similar measures.

Use

Prevalence of use

As of 2013, there are several million e-cigarette users globally. Awareness and use of e-cigarettes greatly increased over the few years to 2014, particularly among young people and women in some countries. E-cigarette use among young people exceeds traditional cigarette use. People with higher incomes are more likely to have heard of e-cigarettes, but those with lower incomes are more likely to have tried them. Trying e-cigarettes was common among less educated people. Whites are more likely to use them than non-whites. Most users have a history of smoking normal cigarettes. Some young people who have never smoked normal cigarettes have tried e-cigarettes at least once.

The majority of e-cigarette users use them every day. E-cigarette users mostly keep smoking traditional cigarettes. Many users say e-cigarettes help them cut down or quit smoking. Adults most often use e-cigarettes to replace tobacco, but not always to quit. Most e-cigarette users are middle-aged men who also smoke traditional cigarettes, either to help them quit or for recreational use. Among women, e-cigarette use is rising sharply. E-cigarette use is also rising among women of childbearing age, but the rate of use during pregnancy is unknown. Dual use of e-cigarettes and traditional tobacco is still a definite concern. Many worry that e-cigarettes may function as a "gateway" to using traditional cigarettes. There are ethical concerns about e-cigarette use among minors and their potential to weaken efforts to reduce the use of traditional cigarettes.

In the United States, as of 2011, one in five adults who smoke have tried electronic cigarettes and 3.3% are currently using them. Among grade 6 to 12 students in the United States, those who have at least once used the product increased from 3.3% in 2011 to 6.8% in 2012 and those currently using electronic cigarettes increased from 0.6% to 1.1%. Over the same period the percentage of grade 6 to 12 students who regularly smoke tobacco cigarettes fell from 7.5% to 6.7%. Use frequency has risen: as of 2012, up to 10% of American high school students have ever used them. In 2013 the CDC found a threefold increase from 2011 in the number of youth who have used e-cigarettes but have never smoked. Between 2013 and 2014, use of e-cigarettes by US teenagers tripled. The limited data suggests e-cigarette use is rapidly growing among adolescents. The majority of young people who use e-cigarettes also smoke combustible cigarettes. E-cigarette use among never-smoking youth in the US correlates with an elevated wish to use traditional cigarettes.

In the UK in 2014, 18% of regular smokers said they used e-cigarettes and 51% said they had used them in the past. Among those who had never smoked, 1.1% said they had tried them and 0.2% still use them. In 2013, among those under 18, 7% have used e-cigarettes at least once. Among non-smokers' children, 1% reported having tried e-cigarettes "once or twice", and there was no evidence of continued use. Sustained use was mostly confined to children who smoke or have smoked. In 2014 child regular users was at 1.8%, children who have ever used e-cigarettes was at 10%, and occasional or greater use among never-smoking children was at 0.18%. About 60% are smokers and most of the rest are ex-smokers.

A February 2014 survey in France estimated that between 7.7 and 9.2 million people have tried e-cigarettes, with 1.1 to 1.9 million using them on a daily basis. 67% of tobacco smokers in the survey used e-cigarettes to reduce or quit tobacco smoking. 9% of those who tried e-cigarettes had never smoked tobacco. Of the 1.2% that had recently stopped tobacco smoking at the time of the survey, 84% (or 1% of the population surveyed) credited e-cigarettes for stopping tobacco use.

Larger numbers of young people are starting to use e-cigarettes. Many young people who use e-cigarettes also smoke traditional cigarettes. Some youths who have tried an e-cigarette have never smoked a traditional cigarette; this indicates they can be a starting point for nicotine use. There are high levels of dual use with e-cigarettes and traditional cigarettes. Most young people are not using e-cigarettes to help them quit tobacco.

Motivation for use

File:Bangor bilingual station no smoking sign.jpg

Common reasons people use the e-cigarette is a desire to quit smoking cigarettes, cut down on their smoking habit or for use where smoking is prohibited by law.

There are varied reasons for e-cigarette use. Studies suggest most users' motivation is related to quitting, but a considerable proportion of use is recreational. Reasons for trying e-cigarettes are partly due to curiosity and experimentation rather than ongoing use. Some vapers use e-cigarettes for the enjoyment. E-cigarettes are used for relaxation, and it is used to practice tricks like blowing smoke rings. Many users assume that e-cigarettes are healthier than traditional cigarettes for personal use or for other people. Some users are concerned about the possible adverse health effects or toxicity of e-cigarettes. People who think e-cigarettes are less toxic than smoking may be more likely to experiment with them. Marketing strategies directed at smokers frequently draw comparison with regular cigarettes by suggesting e-cigarette devices are "newer, healthier, cheaper and easier to use in smoke-free situations, all reasons that e-cigarette users claim motivate their use".

A 2015 review said that if tobacco businesses persuade women that e-cigarettes are a small risk, non-smoking women of reproductive age might begin using them and women smoking during pregnancy might shift to their use or use these devices to reduce smoking, instead of stopping using traditional cigarettes. Another 2015 review said that the belief that e-cigarettes are safer than traditional cigarettes could widen their use for pregnant women. Traditional cigarette users who have not used e-cigarettes had mixed ideas about their possible satisfaction and around a third thought that e-cigarettes might taste bad. Vapers disagreed whether it was a benefit or a drawback that they feel or taste similar to traditional cigarettes. Some traditional cigarette users and e-cigarette users liked that e-cigarettes resembled traditional cigarettes, whereas others thought this was a drawback. E-cigarettes users' views about saving money from using e-cigarettes compared to traditional cigarettes are inconsistent. The majority of committed e-cigarette users interviewed at an e-cigarette convention found them less costly than traditional cigarettes.

Some users stopped using e-cigarettes due to issues with the devices. Not having odor from smoke on clothes on some occasions prompted interest in or use of e-cigarettes. Although some people want to quit smoking using e-cigarettes, others use them to circumvent smoke-free laws and policies, or to cut back on normal cigarette smoking. E-cigarette users have contradictory views about using them to get around smoking bans. Some surveys found that a small percentage of users' motives was to avoid the bans, but other surveys found that over 40% of users said they used the device for this reason. The extent to which traditional cigarette users use e-cigarettes to avoid smoking bans is unclear.

A 2014 review found "Health-related and lifestyle appeals may also encourage initiation among young non-smokers, as they may convey that trying e-cigarettes is less risky and more socially appealing, which may ameliorate negative beliefs or concerns about nicotine addiction." Adolescent experimenting with e-cigarettes may be related to sensation seeking behavior, and is not likely to be associated with tobacco reduction or quitting smoking. Young people and children are tempted by flavored e-cigarettes. The main reasons young people experimented with e-cigarettes were due to curiosity, flavors, and peer influences. E-cigarettes can appeal to youth because of their high-tech design, assortment of flavors, and accessibility online. E-cigarettes could be more appealing to non-smoking youths than traditional cigarettes. In the US, the North West of England and Paris, use of e-cigarettes by children may be due to experimentation. In North Wales, girls who use e-cigarettes consider them appealing. Infants and toddlers could ingest the e-liquid from an e-cigarette device out of curiosity.

Many users might begin by using a disposable e-cigarette. E-cigarette users often start with an e-cigarette resembling a normal cigarette and eventually most of them switch to a later-generation device. Most users of later-generation e-cigarettes shifted to their present model to get a "more satisfying hit". Many users enjoy adjusting their devices to provide more vapor for better throat hits.

Construction

Disassembled cigarette-styled electronic cigarette.
A. LED light cover
B. battery (also houses circuitry)
C. atomizer (heating element)
D. cartridge (mouthpiece)

A disposable e-cigarette.

E-cigarettes are generally roughly cylindrical, with many variations: pen-styles, tank-styles etc. There are three main categories of e-cigarettes: cigalikes, looking like cigarettes; eGos, bigger than cigalikes with refillable liquid tanks; and mods, assembled from basic parts or by altering existing products. E-cigarettes are also available that resemble pens and USB memory sticks for those who may want to use the device unobtrusively. First generation e-cigarettes usually simulated smoking implements, such as cigarettes or cigars, in their use and appearance. Later-generation e-cigarettes often called mods, PVs (personal vaporizer) or APVs (advanced personal vaporizer) have an increased nicotine-dispersal performance, housing higher capacity batteries, and come in various form factors, including metal tubes and boxes. Many electronic cigarettes are composed of standardized replaceable parts that are interchangeable from one brand to the other. Common components include a liquid delivery and container system like tanks or cartomizers, an atomizer, and a power source. A wide array of component combinations exist. Many e-cigarettes are available with a USB charger to enable the user to re-charge the device. The main parts for most e-cigarettes include an aerosol generator, flow sensor, battery, and a liquid storage chamber. They contain silver, steel, metals, ceramics, plastics, fibers, aluminum, rubber and spume, and lithium batteries. As the e-cigarette industry is growing, new products are quickly developed and brought to market.

E-cigarettes are available in disposable or reusable variants. Disposable e-cigarettes are discarded once the liquid in the cartridge is used up, while rechargeable e-cigarettes may be used indefinitely. Reusable e-cigarettes are refilled by hand or exchanged for pre-filled cartridges, and general cleaning is required. A wide range of disposable and reusable e-cigarettes exist. Disposable e-cigarettes are available for a few dollars, and higher priced reusable e-cigarettes involve an up-front investment for a starter kit. Once the user inhales, the airflow activates the sensor, and then the heating element atomizes the liquid solution inside the cartridge into vapor. Other e-cigarettes have a manual push-button switch to turn on the device. Some e-cigarettes have a light-emitting diode at the tip to resemble the glow of burning tobacco. The light-emitting diode may also indicate the battery status. A traditional cigarette is smooth and light, while an e-cigarette can be rigid and a bit bulky. In comparison to traditional cigarettes, the general e-cigarette puff time was much longer, and e-cigarette use needed a more forceful suction.

Device generations

First generation

Aerosol (vapor) exhaled by a first generation e-cigarette user.

First generation e-cigarettes tend to look like tobacco cigarettes and so are called "cigalikes". They may be a single unit comprising a battery, coil and filling saturated with e-juice in a single tube to be used and discarded after the battery or e-liquid is depleted. They may also be a reusable device with a battery and cartridge called a cartomizer. The cartomizer cartridge can be separated from the battery so the battery can be charged and the empty cartomizer replaced when the e-juice runs out. The battery may contain an electronic airflow sensor triggered by drawing breath through the device. Other models use a power button that must be held during operation. An LED in the power button or on the end of the device may also show when the device is firing. Charging is commonly accomplished with a USB charger that attaches to the batteru. Some manufacturers also have a cigarette pack-shaped portable charging case (PCC), which contains a larger battery capable of recharging the individual e-cigarette batteries. Reusable devices can come in a kit that contains a battery, a charger, and at least one cartridge. Varying nicotine concentrations are available and nicotine delivery to the user also varies based on different cartomizers, e-juice mixtures, and power supplied by the battery. These manufacturing differences, creates differences in the way e-cigarettes convert the liquid solution to an aerosol, and thus the levels of ingredients, that are delivered to the user and the surrounding air for any given liquid.

Second generation

Second generation PV.

Second generation devices tend to be used by more experienced users. These devices are larger overall and look less like tobacco cigarettes. They have larger non removable batteries with higher capacity. They are charged with a USB charger that attaches to the battery with a threaded connection. Some batteries have a "passthrough" feature so they can be used even while they are charging. Second generation devices are usually two part devices with a tank and a separate battery. Because the tank can be refilled and the battery recharged, the cost of operation is lower. Second generation e-cigarettes commonly use a tank or a "clearomizer". The clearomizer tanks are meant to be refilled with e-juice. They can also be used with cartomizers which are pre-filled. Some cheaper batteries use a microphone that detects the vibration of the air passing through to activate the device when the user inhales. Other batteries like the eGo style can use a custom integrated circuit with a button for manual activation and battery status indicated on the included LED. The power button can also used to turn the battery off and on so it is not activated accidentally. These batteries may also have adjustable power or voltage.

Third generation

Third generation PV.

Third generation devices include mechanical mods and variable voltage devices. The battery sections are commonly called "mods," referencing their history of user-modification. These devices are commonly either cylindrical or a box-shaped. They can be made of wood, aluminium, stainless steel, or brass. A larger "box mod" can hold larger and sometimes multiple batteries. Mechanical mods and variable devices use larger batteries than those found in previous generations. The battery is often replaceable. This allows the user to change to a new battery when one is depleted. Variable devices often have a USB connector for recharging and some can be used while charging which is referred to as a "passthrough" feature. Mechanical mods do not have built in chargers because they do not contain integrated circuits, only a switch that connects the atomizer to the battery. The battery must be removed and charged with an external charger. Common battery sizes used in mechanical mods and variable wattage devices are 18350, 18490, 18500 and 18650. The power section may include additional options such as screen readout, support for a wide range of internal batteries, and compatibility with different types of atomizers. Third generation devices commonly use rebuildable atomizers that can be utilize different wicking materials. These rebuildable devices use handmade coils that can be installed in the atomizer to increase vapor production. Hardware in this generation is sometimes modified to increase power or flavor. The larger battery sections used also allow larger tanks to be attached that can hold more e-liquid. A fourth generation digital e-cigarette became available in the U.S. in 2014.

Atomizer

An e-cigarette atomizer with the coil (heating element) in view.

An atomizer comprises a small heating element that vaporizes e-liquid and a wicking material that draws liquid onto the coil. Along with a battery, the atomizer is the central component of every personal vaporizer. A small length of resistance wire is coiled around the wicking material and connected to the integrated circuit, or in the case of mechanical devices, the atomizer is connected directly to the battery through a switch. When activated, the resistance wire coil heats up and vaporizes the liquid, which is then inhaled by the user.

The electrical resistance of the coil, the voltage output of the device, the airflow of the atomizer and the efficiency of the wick all affect the vapor coming from the atomizer. They also affect the vapor quantity or volume yielded.

Atomizer resistances usually vary from 1.5Ω (ohms) to 3.0Ω, but they can go as low as 0.1Ω in the most extreme cases of DIY coil building. Coils of lower ohms have increased vapor production but could risk fire and dangerous battery failures if the user is not knowledgeable enough about electrical principles and how they relate to battery safety.

Wicking materials vary from one atomizer to another but silica fibers are most common. "Rebuildable" or "do it yourself" atomizers can use silica, cotton, rayon, porous ceramic, hemp, bamboo yarn, oxidized stainless steel mesh and even wire rope cables as wicking materials.

Cartomizers

A 45mm length, extra-long cartomizer.

A "cartomizer" (a portmanteau of cartridge and atomizer) or "carto" consists of an atomizer surrounded by a liquid-soaked poly-foam that acts as an e-liquid holder. They can have up to 3 coils and each coil will increase vapor production. The cartomizer is usually disposed of once the e-liquid acquires a burnt taste, which is usually due to an activation when the coil is dry or when the cartomizer gets consistently flooded (gurgling) because of sedimentation of the wick. Most cartomizers are refillable even if not advertised as such.

Cartomizers can be used on their own or in conjunction with a tank that allows more e-liquid capacity. In this case the portmanteau word of "cartotank" has been coined. When used in a tank, the cartomizer is inserted in a plastic, glass or metal tube and holes or slots have to be punched on the sides of the cartomizer to allow liquid to reach the coil.

Clearomizers

eGo style e-cigarette with a top-coil clearomizer. Silica fibers are hanging down freely inside of the tank, drawing e-liquid by capillary action to the coil that is located directly under the mouthpiece.

Clearomizers or "clearos", not unlike cartotanks, use a clear tank in which an atomizer is inserted. Unlike cartotanks, they do not use a poly-foam material. There are many different wicking systems used inside clearomizers to maintain balance between good moistening of the wick versus too much liquid which can flood the coil. Some rely on gravity to bring the e-liquid to the wick and coil assembly (bottom coil clearomizers for example) and others rely on capillary action or to some degree the user agitating the e-liquid while handling the clearomizer (top coil clearomizers). The coil and wicks are typically inside a prefabricated assembly or "head" that is replaceable by the user and can contain single or dual coils.

Present day clearomizers often have adjustable air flow control. They also hold up to 5ml of e-liquid. Tanks can be plastic, glass, stainless steel, or a combination of those materials. Some flavors of e-juice have been known to damage plastic clearomizer tanks.

Rebuildable atomizers

A rebuildable atomizer or an RBA is an atomizer that allows the user to assemble or "build" the wick and coil themselves instead of replacing them with off-the-shelf atomizer "heads". They are generally considered advanced devices. They also allow the user to build atomizers at any desired electrical resistance.

These atomizers are divided into three main categories; rebuildable tank atomizers (RTAs), rebuildable dripping atomizers (RDAs), and rebuildable dripping tank atomizers (RDTAs).

Rebuildable tank atomizers (RTAs) are similar to clearomizers in that they use a tank to hold liquid that is absorbed by the wick. They usually hold significantly more e-liquid than other atomizers or clearomizers. The tank can be either plastic, glass, metal, or a combination. An early form of tank atomizers was the Genesis style atomizers. They commonly use stainless steel mesh or rope for wicking material. The steel wick must be oxidized to prevent arcing of the coil. One drawback of the Genesis style atomizers was they would often leak if they were not not always held upright.

Rebuildable dripping atomizers (RDAs) are atomizers where the e-juice is dripped directly onto the coil and wick. They typically consist only of an atomizer "building deck", commonly with three posts with holes drilled in them, which can accept one or more coils. A "top cap" is used to cover the coils and feature a hole at the top where a mouth piece can be attached. The wick is generally larger than those found in tank atomizers. The user needs to manually keep the atomizer wet by dripping liquid on the bare wick and coil assembly, hence their name. Modern dripping atomizers can have raised edges forming a cup or "juice well". This allows more wick to be used and helps stop leaking. Some atomizers have heat sink fins to dissipate the heat from the coil before it reaches the mouth piece or "drip tip".

Rebuildable dripping tank atomizers (RDTAs) are a combination of both RTAs and RDAs. They usually consist of a RDA build deck with a tank over the deck held up by a spring. The user pushes down on the mouth piece and liquid is then dripped onto the coils and wick. This is unlike a RTA that continuously feeds liquid to the wicks via gravity or capillary action.

Power

Variable power and voltage devices

PV with variable and regulated power offering battery protection.

The devices contain a rechargeable battery, which tends to be the largest component of an electronic cigarette. Many devices feature variable power and/or variable voltage and contain a built-in electronic chip allowing the user to adjust the power that is applied to the heating element. The devices are often rectangular in shape but can also be cylindrical. They usually incorporate a screen to display information like voltage, power, and resistance of the coil.

Variable devices are either variable wattage, variable voltage or both. Variable wattage devices allow the user to adjust the voltage applied to the coil. The devices monitor the coil's resistance and automatically adjust the voltage to apply the user-specified level of power to the coil. To adjust the settings the user presses buttons or rotates a dial to make adjustments in power either up or down. The amount of power applied to the coil has a direct relationship to the heat produced, thus changing the vapor output. Greater heat generated by the coil increases vapor production. Some of these devices include additional settings through their menu system such as: atomizer resistance meter, remaining battery voltage, puff counter, and power-off or lock.

Mechanical personal vaporizers

Mechanical PV with a rebuildable atomizer.

Mechanical PVs or mechanical "mods", often called "mechs", are devices without integrated circuits, electronic battery protection, or voltage regulation. Because there is neither protection nor regulation, they will work regardless of the the battery's orientation. They are activated by spring loaded or opposing magnetic mechanical switches, hence their name. They rely on the natural voltage output of the battery and the metal that the mod is made of often is used as part of the circuit itself.

The term "mod" was originally used instead of "modification". Users would modify existing hardware to get better performance, and as an alternative to the e-cigarettes that looked like traditional cigarettes. Users would also modify other unrelated items like flashlights as battery compartments to power atomizers. Today the word mod is used to describe most personal vaporizers either bought in a store or created by the user.

Because mechanical PVs have no power regulation and are unprotected, they require special attention from the user beyond what is required with other regulated and protected PVs do not require. Ensuring that the battery does not over-discharge and that the resistance of the atomizer requires an amperage within the safety limits of the battery is the responsibility of the user.

E-liquid

E-liquid, e-juice or simply "juice", is the liquid that vaporizes when heated. There is a vast array of e-liquids available. The main ingredients are propylene glycol, glycerin, water, nicotine, and flavorings; and optionally, tobacco-derived nicotine. The liquid typically contains 95% propylene glycol and glycerin. The most regularly used base carrier chemical is propylene glycol with or without glycerin. E-liquid containing glycerin and water made without propylene glycol is also available. The nicotine in e-liquid may be prepared using a United States Pharmacopeia-grade nicotine, a tobacco plant extract, tobacco dust or a synthetic nicotine. Most e-cigarette liquids contain nicotine, but the level of nicotine varies depending on user-preference and manufacturers. E-liquid without nicotine is also available. Although some e-juice is nicotine-free, surveys demonstrate that 97% of e-cigarette users use products that contain nicotine.

The solution is often sold in bottles or pre-filled disposable cartridges, or as a kit for consumers to make their own e-juices. Components are also available to modify or boost their flavor or nicotine strength. Pre-made e-liquids are made with various tobacco, fruit, and other flavors, as well as variable nicotine concentrations (including nicotine-free versions). The standard notation "mg/ml" is often used on labels to denote nicotine concentration, and is sometimes shortened to "mg". In surveys of regular e-cigarette users, the most popular e-liquids have a nicotine content of 18 mg/ml, and the preferred flavors were largely tobacco, mint and fruit. A cartridge may contain 0 to 20 mg of nicotine. A refill bottle can contain up to 1 g of nicotine. The flavorings may be natural or artificial. Some liquids without flavoring is also available. A user does not normally consume a whole cartridge in a single session.

Health effects

Positions of medical organizations

Main article: Positions of medical organizations regarding electronic cigarettes

As of 2014 electronic cigarettes had not been approved as a smoking cessation device by any government. In July 2014, a report produced by the World Health Organization (WHO) for the WHO Framework Convention on Tobacco Control, found there was not enough evidence to determine if electronic cigarettes can help people quit smoking. It suggested that smokers should be encouraged to use approved methods for help with quitting. But the same report also mentioned expert opinions in scientific papers that suggested e-cigarettes may have a role helping people quit who have failed using other methods. A previous WHO statement from July 2013 said that e-cigarettes have not been shown to help people quit smoking. It also recommended that "consumers should be strongly advised not to use" e-cigarettes unless a reputable national regulatory body has found them safe and effective. The World Lung Foundation applauded the WHO report's recommendation for tighter regulation of e-cigarettes due to concerns about the safety of e-cigarettes and the risk of increased nicotine or tobacco addiction among youth.

The UK National Health Service concluded that "While e-cigarettes may be safer than conventional cigarettes, we don't yet know the long-term effects of vaping on the body. There are clinical trials in progress to test the quality, safety and effectiveness of e-cigarettes, but until these are complete, the government can't give any advice on them or recommend their use."

In 2014, the US Food and Drug Administration (FDA) said "E-cigarettes have not been fully studied, so consumers currently don't know: the potential risks of e-cigarettes when used as intended, how much nicotine or other potentially harmful chemicals are being inhaled during use, or whether there are any benefits associated with using these products. Additionally, it is not known whether e-cigarettes may lead young people to try other tobacco products, including conventional cigarettes, which are known to cause disease and lead to premature death."

Smoking cessation

As of 2014, research on the safety and efficacy of e-cigarette use for smoking cessation is limited. They are unproven as quit-smoking aids. Their benefit for quitting smoking is uncertain. The evidence suggests that e-cigarettes can supply nicotine at concentrations that are, at least partially, enough to substitute for traditional cigarettes. While there are some reports of improved smoking cessation, especially with intensive e-cigarette users, there are also several studies showing a decline in cessation in dual users. A 2014 Cochrane review found limited evidence of a benefit as a smoking cessation aid from a small number of studies. A 2015 review concluded that while they may have a benefit for decreasing cigarette use in smokers, they have a limited benefit in quitting smoking. A 2014 review found e-cigarettes may have some potential for reducing smoking.

A 2015 review found variable quality evidence that e-cigarette users had higher cessation rates than users of nicotine replacement products. A 2014 review found limited quality evidence that e-cigarettes do not seem to improve cessation rates compared to regulated FDA nicotine replacement products. Two 2014 reviews found no evidence that e-cigarettes are more effective than existing nicotine replacement products for smoking cessation. They may be as effective, but not more, compared to nicotine patches for short-term smoking cessation. However, a randomized trial found 29% of e-cigarette users maintained e-cigarette use at 6 months while 8% for patch users, indicating the use of e-cigarettes could continue after other quit methods. Studies have not shown that e-cigarettes are better than regulated medication for smoking cessation. A 2014 review found four experimental studies and six cohort studies that indicated that electronic cigarettes reduced the desire to smoke and withdrawal symptoms. This review also noted that two cohort studies found that electronic cigarettes led to a reduction in the number of cigarettes smoked per day. Nicotine-containing e-cigarettes were associated with greater effectiveness for quitting smoking than e-cigarettes without nicotine. A 2014 review concluded that the adverse public health effects resulting from the widespread use of e-cigarettes could be significant, in part due to the possibility that they could undermine smoking cessation. This review therefore called for their use to be limited to smokers who are unwilling or unable to quit. A 2014 review found that the research suggested that personal e-cigarette use may reduce overall health risk in comparison to traditional cigarettes. However, e-cigarettes could have a broad adverse effect for a population by expanding initiation and lowering cessation of smoking. A 2014 review found that the evidence suggests that "e-cigarettes are not associated with successful quitting in general population-based samples of smokers."

Harm reduction

Tobacco harm reduction has been a controversial area of tobacco control. The health community has not been willing to endorse e-cigarettes as a tobacco harm reduction strategy, in part in response to tobacco industry deception. A 2014 review concluded promotion of e-cigarettes as a harm reduction aid is premature. Another review found e-cigarettes would likely be less harmful to users and bystanders. The authors warned against the potential harm of excessive regulation and advised that health professionals may consider advising smokers who are reluctant to quit by other methods to switch to e-cigarettes as a safer alternative to smoking. A 2014 review argued that regulations for e-cigarettes should be similar to those for dietary supplements or cosmetic products to not limit their potential for harm reduction. E-cigarettes may have potential in harm reduction compared to using other tobacco products. When used to quit smoking, they could reduce harm even more if the tobacco user quits but e-cigarettes are not harmless because nicotine has long-term adverse effects, may contain impurities, and nicotine is addictive, which may have serious side effects, particularly if users use unconventional ways to increase the doses of nicotine exposure. A 2012 review found electronic systems appear to generally deliver less nicotine than smoking, raising the question of whether they can effectively substitute for tobacco smoking over a long-term period. A 2012 review found e-cigarettes could considerably reduce traditional cigarettes use and they likely could be used as a lower risk replacement for traditional cigarettes, but there is not enough data on the safety and efficacy to draw definite conclusions. E-cigarette use for risk reduction in high-risk groups such as people with mental disorders is unavailable.

Smoke from traditional tobacco products has 40 known carcinogens among the 10,000 chemicals it contains, none of which has been found in more than trace quantities in the cartridges or aerosol of e-cigarettes. A 2011 review stated that while e-cigarettes can not be considered "safe" because there is no safe level for carcinogens, they are doubtless safer compared to tobacco cigarettes. Any residual risk of e-cigarette use should be weighed relative to the risk of continuing or returning to smoking, taking account of the low success rate of currently-approved smoking cessation medications. Adults most frequently use electronic cigarettes as a replacement for tobacco, but not always to quit. Although some people have a desire to quit smoking by using e-cigarettes, another common explanation for the use of these products is to cut back on traditional cigarettes.

In 2014 a report commissioned by Public Health England concluded that there is large potential for health benefits when switching from tobacco use to other nicotine delivery devices such as electronic cigarettes, but realizing their full potential requires regulation and monitoring to minimize possible risks. They found that the evidence suggests that a considerable number of smokers want to reduce harm from smoking by using these products. The British Medical Association encourages health professionals to recommend conventional nicotine replacement therapies, but for patients unwilling to use or continue using such methods, health professionals may present e-cigarettes as a lower-risk option than tobacco smoking. The American Association of Public Health Physicians (AAPHP) suggests those who are unwilling to quit tobacco smoking or unable to quit with medical advice and pharmaceutical methods should consider other nicotine containing products such as electronic cigarettes and smokeless tobacco for long term use instead of smoking. In an interview, the director of the Office on Smoking and Health for the U.S. federal agency Centers for Disease Control and Prevention (CDC) believes that there is enough evidence to say that using e-cigarettes is likely less harmful than smoking a pack of conventional cigarettes. However, due to the lack of regulation of the contents of the numerous different brands of electronic cigarettes and the presence of nicotine, which is not a benign substance, the CDC has issued warnings. A 2014 WHO report concluded that some smokers will switch completely to e-cigarettes from traditional tobacco but a "sizeable" number will use both tobacco cigarettes and electronic cigarettes. This report found that such "dual use" of e-cigarettes and tobacco "will have much smaller beneficial effects on overall survival compared with quitting smoking completely."

Safety

Main article: Safety of electronic cigarettes

The risks of electronic cigarette use are uncertain. There is little data about their health effects, and considerable variability between vaporizers and the contents of the aerosol delivered to the user. The limited evidence suggests that e-cigarettes are probably safer than traditional cigarettes. One review found, from limited data, their safety risk is similar to that of smokeless tobacco, which has about 1% of the mortality risk of traditional cigarettes. Another concluded that regulated FDA products such as a nicotine inhaler are probably a safer way to supply nicotine than e-cigarettes. E-cigarettes create vapor that consists of ultrafine particles. The vapor has been found to contain flavors, propylene glycol, glycerin, nicotine, tiny amounts of toxicants and heavy metals, and other chemicals. E-cigarette vapor contains fewer toxic substances than cigarette smoke. Various methodological issues, conflicts of interest, and inconsistent research has been identified in the research regarding e-cigarettes. However, e-cigarettes cannot be regarded as simply harmless. As well as toxicity there are also risks from misuse or accidents (e.g., accidental fires caused by vaporizer malfunction, other vaporizer design issues, or accidental contact with liquid nicotine).

A July 2014 WHO report cautioned about potential risks of using e-cigarettes. The report concluded that "the existing evidence shows that ENDS aerosol is not merely "water vapour" as is often claimed in the marketing for these products. ENDS use poses serious threats to adolescents and fetuses." A 2014 systematic review concluded that the risks of e-cigarettes have been exaggerated by health authorities and stated that there may be some remaining risk, though the risk of e-cigarette use is likely small compared to smoking tobacco. A 2014 Cochrane review found no serious adverse effects reported in trials. Less serious adverse effects from e-cigarette use can include throat and mouth inflammation, vomiting, nausea, and cough. The long-term effects of e-cigarette use are unknown. The risk is probably low from the inhalation of propylene glycol and glycerin. E-cigarette users are exposed to potentially harmful nicotine. A 2014 review recommended that e-cigarettes should be regulated for consumer safety.

Addiction

A number of organizations are concerned that e-cigarettes might increase addiction to and use of nicotine and tobacco products among young people. These include the Centers for Disease Control and Prevention, the International Union Against Tuberculosis and Lung Disease, the American Academy of Pediatrics and the Food and Drug Administration. The World Health Organization raised concern about addiction for nonsmokers from their use in July 2013. The National Institute on Drug Abuse said they could maintain addiction to nicotine in those who are attempting to quit.

The nicotine molecule.

It is not clear whether using e-cigarettes will decrease or increase overall nicotine addiction. Information about the drug action of the nicotine in e-cigarettes is limited. The evidence suggests that the nicotine in e-cigarettes is adequate to sustain nicotine dependence. The limited data suggests that the likelihood of abuse from e-cigarettes could be smaller than traditional cigarettes. A 2014 systematic review found that the concerns that e-cigarettes could cause non-smokers to start smoking are unsubstantiated. A 2014 review found no evidence that they are used regularly by those who have never smoked, while another 2014 review has found that in some populations nearly up to a third of youth who have ever used e-cigarettes have never smoked traditional cigarettes. No long-term studies have been done on the effectiveness of e-cigarettes in treating tobacco addiction. The degree to which teens are using e-cigarettes in ways the manufacturers did not intend, such as increasing the nicotine delivery, is unknown. The extent to which e-cigarette use will lead to abuse in youth is unknown. The impact of e-cigarette use by children on substance dependence is unknown. Some evidence suggests that dual use of e-cigarettes and traditional cigarettes may be associated with greater nicotine dependence.

History

The earliest electronic cigarette can be traced to Herbert A. Gilbert, who in 1963 patented a device described as "a smokeless non-tobacco cigarette" that involved "replacing burning tobacco and paper with heated, moist, flavored air". This device heated the nicotine solution and produced steam. It was never commercialized.

Hon Lik, a Chinese pharmacist and inventor, who worked as a research pharmacist for a company producing ginseng products, is credited with the invention of the modern electronic cigarette. Hon quit smoking after his father, also a heavy smoker, died of lung cancer. In 2003, he came up with the idea of using a piezoelectric ultrasound-emitting element to vaporize a pressurized jet of liquid containing nicotine diluted in a propylene glycol solution. This design produces a smoke-like vapor that can be inhaled and provides a vehicle for nicotine delivery into the bloodstream via the lungs. He also proposed using propylene glycol to dilute nicotine and utilizing a disposable plastic cartridge to serve as a liquid reservoir and mouthpiece.

Hon patented the modern e-cigarette design in 2003. Electronic cigarettes using a different designs were first introduced to the Chinese domestic market in May 2004 as an aid for smoking cessation and replacement. Many versions made their way to the U.S., sold mostly over the Internet by small marketing firms. The company that Hon Lik worked for, Golden Dragon Holdings, changed its name to Ruyan (如烟, literally "Resembling smoking"), and started exporting its products in 2005–2006 before receiving its first international patent in 2007.

The electronic cigarette continued to evolve from the first generation three-part device. In 2006 the "cartomizer" was invented by British entrepreneurs Umer and Tariq Sheikh of XL Distributors. This is a mechanism which integrates the heating coil into the liquid chamber. The new device was launched in the UK in 2007 under their Gamucci brand and the design is now widely adopted by the majority of 'cigalike' brands. The grant of the UK patent for the "cartomizer" was made to XL Distributors in February 2013 and published by the UK Intellectual Property Office. Since 2007, e-cigarette use in the US has risen.

International tobacco companies, recognizing the development of a potential new market sector that could render traditional tobacco products obsolete, are increasingly involved in the production and marketing of their own brands of e-cigarettes and in acquiring existing e-cigarette companies. Blu, a prominent US e-cigarette manufacturer, was acquired by Lorillard Inc. in 2012. British American Tobacco launched Vype in 2013, while Imperial Tobacco's Fontem Ventures acquired the intellectual property owned by Hon Lik through Dragonite for $US 75 million in 2013 and launched Puritane in partnership with Boots UK. On 1 October 2013 Lorillard Inc. acquired another e-cigarette company, this time the UK based company SKYCIG. On 3 February 2014, Altria Group, Inc. acquired popular electronic cigarette brand Green Smoke for $110 million. The deal was finalized in April 2014 for $110 million with $20 million in incentive payments. Altria also markets its own e-cigarette, the MarkTen, while Reynolds American has entered the sector with its Vuse product. As of March 2015, 74% of all e-cigarette sales in convenience stores in the U.S. were products made by tobacco companies.

Society and culture

Consumers of electronic cigarettes, sometimes referred to as "vapers", have shown evident and passionate support for the product that other nicotine replacement therapy did not receive. This suggests that electronic cigarettes have the potential mass appeal that could challenge the preeminence of combustible tobacco as the object of choice for nicotine users.

As the electronic cigarette industry grows, a subculture has emerged which calls itself "the vaping community". The online forum E-Cig-Reviews.com was one of the first major communities. Another online forum known as UKVaper.org was the origin of the hobby of modding. There are also groups on Facebook and Reddit. Members of this emerging subculture often view electronic cigarettes as a safer alternative to smoking and some even view it as a hobby. These groups tend to use highly customized devices that do not resemble the earlier "cig-a-likes", the electronic cigarettes that resemble real cigarettes. Online forums based around modding have grown in the vaping community. A 2014 Postgraduate Medical Journal editorial stated that e-cigarette companies have a substantial online presence, as well as many individual vapers who spend time blogging and tweeting about e-cigarette related products. The editorial stated that a few vapers "engage in grossly offensive online attacks on anyone who has the temerity to suggest that ENDS are anything other than an innovation that can save thousands of lives with no risks". A 2014 review stated that tobacco and e-cigarette companies interact with consumers for their policy agenda. The companies use websites, social media, and marketing to get consumers involved in opposing bills that include e-cigarettes in smoke-free laws. This is similar to tobacco industry activity going back to the 1980s. It was concluded that these approaches were used in Europe to minimize the EU Tobacco Product Directive in October 2013.

Large gatherings of vapers, called vape meets, are happening around the United States. They focus on e-cig devices, accessories, and the lifestyle that accompanies them. Vapefest, which started in 2010, is an annual show hosted by different cities. People attending these meetings are usually enthusiasts that use specialized, community-made products that are not found in typical places like convenience stores or gas stations. These products are mostly available online or in dedicated "vape" storefronts where mainstream e-cigarettes brands from the tobacco industry and larger e-cig manufacturers are not as popular. As of 2014, availability of e-cigarettes is increasing in retail stores in the U.S., especially in places with low taxed and smoking ban regulations.

A growing subclass of vapers called "cloud-chasers" assemble their atomizers in such a way that can produce extremely large amounts of vapor by using heating coils with a resistance of less than 1 ohm. This practice is known as "cloud-chasing". By using a coil with very low resistance,the batteries used are stressed beyond the margins of what could be considered safe use. This could represent a risk of dangerous battery failures. As vaping comes under more and more scrutiny, some members of the vaping community have voiced their concerns about cloud-chasing, claiming the practice gives vapers a bad reputation when doing it in public. The Oxford Dictionaries' word of the year for 2014 is 'vape'.

Legal status

Main article: Legal status of electronic cigarettes

Because of the novelty of the technology and the possible relationship to tobacco laws and medical drug policies, electronic cigarette legislation is currently pending in many countries. As of 2015, around two thirds of major nations have regulated e-cigarettes in some way. Current regulations vary widely, from regions with no regulations to others banning the devices entirely. For example, some countries such as Brazil, Singapore, the Seychelles, and Uruguay have banned e-cigarettes. In Canada, they are legal to sell, however nicotine-containing e-fluid is not approved by Health Canada - making it technically illegal, although widely unenforced and commonly available for sale. As of 2015, e-cigarettes are legal for minors to buy in a few states in the U.S. and since they do not contain tobacco, television advertising is not restricted. As of 2014, a small number of states in the US allow e-cigarettes to be taxed as tobacco products. In addition, indoor smoking bans have been extended to include e-cigarettes in some states and by regional governments in the US.

In August 2014, attorneys general from over two dozen states advised the FDA to enact restrictions on e-cigarettes, including banning flavors. E-cigarettes have been classified as "drug delivery devices" in several countries because they can contain nicotine, and their advertising has been restricted until safety and efficacy trials are conclusive. A 2014 review said these products should be considered for regulation in view of the "reported adverse health effects". In some countries, e-cigarettes are regulated as a medical product even though they are not approved as a smoking cessation aid. E-cigarettes are not approved by the FDA as a smoking cessation product.

In the fall of 2013, the electronic cigarette industry ran "a determined lobbying campaign" to defeat proposed European legislation to regulate e-cigarettes like medical devices. Pharmaceutical manufacturers GlaxoSmithKline and Johnson & Johnson have lobbied the US government, the FDA, and the EU parliament for stricter regulation of e-cigarettes which compete with their products Nicorette gum and nicotine patches. In February 2014 the European Parliament passed regulations requiring standardization and quality control for liquids and vaporizers, disclosure of ingredients in liquids, and child-proofing and tamper-proofing for liquid packaging. In April 2014 the US FDA published proposed regulations for e-cigarettes along similar lines.

In March 2014 Western Australia banned sale of electronic cigarettes.

In October 2014 the UK's Advertising Standards Authority changed the regulations on e-cigarette advertising, allowing the devices to appear in television ads from 10 November. The first advert to take advantage of the change, promoting KiK Electronic Cigarettes, aired on the day it came into force.

Economics

Hon Lik, the inventor of the modern electronic cigarette sees the electronic cigarette as comparable to the "digital camera taking over from the analogue camera." He has stated: "My fame will follow the development of the e-cigarette industry. Maybe in 20 or 30 years I will be very famous." Many US and Chinese e-cig manufacturers copied his designs illegally, and as a result Hon Lik did not get the expected financial rewards for his invention (although some US manufacturers have compensated him through out of court settlements). Hon Lik's 2003 patents were purchased by Europe's second largest tobacco manufacturer Imperial Tobacco in 2013, for $75 million.

Worldwide e-cigarette sales in 2014 were around $7 billion. E-cigarette brands have been increasing advertising at a fast rate, the aggressive marketing used is similar to that used to sell cigarettes in the 1950s and 1960s. While advertising of tobacco products was banned long ago, television and radio e-cigarette advertising in a number of countries may be indirectly creating a desire for traditional cigarette smoking. There is no evidence that the cigarette brands are selling e-cigarettes as part of a plan to phase out traditional cigarettes, despite some claiming to want to cooperate in "harm reduction". E-cigarettes and nicotine are regularly promoted as safe and beneficial in the media and on brand websites. E-cigarette retail websites often made non-scientific health claims to consumers in order to sell them products. The majority of advertisers also emphasize that the product can be used "anywhere" especially where smoking bans apply. A 2014 review found "only a small percentage of sites had an age restriction, which was only to click a box to state that the user is over a certain age. This easily circumvented age verification leaves open room for youth access and marketing exposure."

Tobacco manufacturers initially dismissed electronic cigarettes as a fad; however, the purchase of the US brand blu eCigs by US tobacco manufacturer Lorillard for $135 million in April 2012 signaled their entry into the market. A national US advertising campaign starred Steven Dorff exhaling a "thick flume" of what the ad describes as 'vapor, not tobacco smoke', exhorting smokers with the message "We are all adults here, it's time to take our freedom back." Jason Healy, founder of blu, called the product "a lifestyle brand for smokers". The ads, occurring against the backdrop of longstanding prohibition of tobacco advertising on television, were criticized by organizations such as Campaign for Tobacco-Free Kids as undermining anti-tobacco efforts. Cynthia Hallett of Americans for Non-Smokers' Rights described the US advertising campaign as attempting to "re-establish a norm that smoking is okay, that smoking is glamorous and acceptable". University of Pennsylvania communications professor Joseph Cappella suggested that the sight of Dorff's exhaled "smoke" would induce tobacco smokers to consume cigarettes, even as the setting of the ad near an ocean was meant to suggest an association of clean air with the nicotine product. The blu brands was purchased by Imperial Tobacco in July 2014. Big tobacco companies have purchased some e-cigarette businesses and greatly increased their marketing efforts. As of 2014 e-cigarette devices are mostly manufactured in China. US e-cigarette sales were forecast to increase to about 5 million units in 2012 compared to 50,000 in 2008. Sales in the U.S. were close to $2 billion in 2014. Big tobacco has a significant share of the e-cigarette market.

In the US there are over a hundred small e-cigarette businesses, with about 70% of the market held by 10 businesses. A sizable share of the e-cigarette business is done on the internet. The majority of e-cigarette businesses have their own homepage and approximately 30–50% of total e-cigarettes sales are handled on the internet in respect to English-language websites. A 2014 review stated that e-cigarettes are aggressively promoted, mostly via the internet, as a healthy alternative to smoking in the US. According to Nielsen Holdings, convenience store e-cigarette sales in the US went down for the first time during the four-week period ending on 10 May 2014. This decline is attributed by Wells Fargo analyst Bonnie Herzog to a shift in consumers behavior, buying more specialized devices or what she refers to as "vapor/tank/mods (VTMs)" that are not tracked by Neilsen. According to Herzog these products, produced and sold by stand alone makers are now (2014) growing 2 times faster than traditional electronic cigarettes marketed by the major players (Lorillard, Logic Technology, NJOY etc...) and account for a third of the 2.2 billion dollar market in the US for vapor products.

There is concern with some financial analysts that the rapid growth of the e-cigarette market is accelerating the decline of $87 billion outstanding in tobacco bonds in the US. States with large populations, such as New York and California, are affected to a greater degree than others.

In the United States, the vaping community and small businesses fear that the proposed regulations by the FDA (2014) concerning electronic cigarette products will impede innovation. and will only benefit the tobacco giants and the pharmaceutical industry by creating a financial burden that specialized, independent companies will not be able to afford, driving them out of business. Some e-cigarette advocates have been worried that the devices could be banned. A 2014 review recommended that e-cigarettes may be regulated to protect users.

The main e-cigarette businesses in the UK are British American Tobacco, Imperial Tobacco, Nicocigs, and Vivid Vapours. British American Tobacco was the first tobacco business to sell e-cigarettes in the UK. They launched the e-cigarette Vype in July 2013. Philip Morris, the world’s largest tobacco manufacturer, purchased UK’s Nicocigs in June 2014. As of March 2014 the top selling e-cigarette brands in the UK at independent convenience stores are Nicolites and Vivid Vapours.

France is a growing market for e-cigarettes, which is said to be about €100 million (£85 million) in sales as of 2013. There are about 150 e-cigarette retail shops in France.

Related technologies

There are other technologies currently under development that seek to deliver nicotine for oral inhalation in an effort to mimic both the ritualistic and behavioral aspects of traditional cigarettes.

British American Tobacco, through their subsidiary Nicoventures Limited, licensed a nicotine delivery system based on existing asthma inhaler technology from UK-based healthcare company Kind Consumer Limited. In September 2014 a product based on this - named Voke - obtained approval from the United Kingdom's Medicines and Healthcare Products Regulatory Agency.

Philip Morris International (PMI) bought the rights to a nicotine pyruvate technology developed by Jed Rose at Duke University. The technology is based on the chemical reaction between nicotine acid and a base, which produces an inhalable nicotine pyruvate vapor.

HeatSticks is a heated tobacco product marketed under the brand Marlboro by PMI.

External links

• Media related to Electronic cigarettes at Wikimedia Commons