An electronic cigarette, also known as an e-cigarette or an e-cig, is an electrical inhaler that vaporizes a propylene glycol- or glycerin- or polyethylene glycol-based liquid solution into an aerosol mist, simulating the act of tobacco smoking. It is often marketed as a smoking cessation aid or tobacco replacement.
The benefits or risks of electronic cigarette use are a subject of uncertainty among health organizations and researchers. Limited controlled studies are available due to their relatively recent invention. Laws governing the use and sale of electronic cigarettes, as well as the accompanying liquid solutions, vary widely, with pending legislation and ongoing debate in many regions.
Hon Lik, a Chinese pharmacist, is widely credited with the invention of the modern electronic cigarette. In 2000, he came up with the idea of using 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 provided a vehicle for nicotine delivery into the bloodstream via the lungs. He also proposed to use propylene glycol to dilute nicotine and place it into a disposable plastic cartridge which serves as a liquid reservoir and mouthpiece. These inventions have laid the basic elements of the present day electronic cigarettes.
The device was first introduced to the Chinese domestic market in May 2004 as an aid for smoking cessation and replacement. The company he worked for, Golden Dragon Holdings, changed its name to Ruyan (literally "Resembling smoking"), and started exporting its products in 2005–2006, before receiving the first international patent in 2007.
Long before the Hon Lik's invention, the primitive concept of an electronic cigarette can trace to an idea by Herbert A. Gilbert, who in 1963 patented a device which was described as, "...a smokeless non-tobacco cigarette ... by replacing burning tobacco and paper with heated, moist, flavored air..." This device heated the nicotine solution and produced steam. In 1967 Gilbert was approached by several companies interested in manufacturing it, but it was never commercialized and has disappeared from the public record after 1967.
An electronic cigarette contains three essential components: A plastic cartridge that serves as a mouthpiece and a reservoir for liquid; an "atomizer" that vaporizes the liquid and a battery.
The cartridge, a small plastic container with openings on each end, serves as both a liquid reservoir and mouthpiece. It allows the passage of liquid to the atomizer and vapor from the atomizer back to the user's mouth, without leaking liquid into the mouth.
Most models adopt a plastic sponge to keep the liquid in place but it is also common to use a refillable tank to carry the liquid with a separate tunnel connecting to the atomizer. When the liquid is depleted, users can refill it or replace it with another pre-filled cartridge. Some users forgo the use of liquid reservoirs and "drip" liquid directly onto the atomizer in a method known as "dripping".
The atomizer contains a small heating coil that vaporizes the liquid, and generally consists of a simple filament and wicking metal mesh to draw the liquid in. It is positioned in the center of the three components that make up the entire electronic cigarette cylinder, as the cartridge attaches to one end, and the power unit to the other. The atomizer's filament will lose efficiency over time due to a buildup of sediment, or "burns out" entirely, requiring replacement. In some models, the cartridge and atomizer component are integrated, known as a cartomizer.
Most portable power units contain a lithium-ion rechargeable battery and makes the largest component of an electronic cigarette. This may contain an electronic airflow sensor so that activation is triggered simply by drawing breath through the device. Other models come with a power switch, which must be held during operation. A LED to announce activation may also be equipped in the front of power unit casing.
Batteries are usually charged via AC outlet, car or USB. Some manufacturers also offer a cigarette-pack-like portable charging case (PCC), which contains a larger battery to charge smaller batteries of individual e-cigarettes.
Liquid for producing vapor in electronic cigarettes, known as e-juice or e-liquid, is a solution of propylene glycol(PG) and/or vegetable glycerin(VG) and/or polyethylene glycol 400(PEG400) mixed with flavors and mostly nicotine.
They are often sold in a bottle or as pre-filled disposable cartridges. Many manufacturers offer dozens of flavors which resemble the taste of regular tobacco, menthol, vanilla, coffee, cola and various fruits, but nicotine concentrations vary by manufacturers. The standard notation "mg/ml" is often used in labeling, sometimes shortened to a simple "mg". Nicotine-free solutions are also common.
Proponents of electronic cigarettes often claim that electronic cigarettes deliver the experience of smoking and greatly minimize the smells and health risks associated with tobacco smoke. The base liquids including propylene glycol(PG), vegetable glycerin(VG), and polyethylene glycol 400(PEG400) have been widely used as food additive, as a base solution for personal care products such as toothpaste, and in medical devices such as asthma inhalers. However, the health effects of inhaling nicotine vapor into lungs have been a subject of uncertainty and no standard GMP procedures have been applied to the production of e-juice.
World Health Organization
The World Health Organization stated in September 2008 that no rigorous, peer-reviewed studies have been conducted showing that the electronic cigarette is a safe and effective nicotine replacement therapy. WHO does not discount the possibility that the electronic cigarette could be useful as a smoking cessation aid, but insisted that claims that electronic cigarettes can help smokers quit need to be backed up by clinical studies and toxicity analyses and operate within the proper regulatory framework.
Food and Drug Administration
In May 2009 the US Food and Drug Administration (USFDA) Division of Pharmaceutical Analysis tested 19 varieties of electronic cigarette cartridges produced by two vendors NJoy and Smoking Everywhere. Diethylene glycol, a poisonous and hygroscopic liquid, was detected in one of the cartridges manufactured by Smoking Everywhere . Tobacco-specific nitrosamines (TSNAs), known cancer-causing agents, were detected in all of the cartridges from one brand and two of the cartridges from the other brand. Nicotine can also be traced in some claimed nicotine-free cartridge. Further concerns were raised over inconsistent amounts of nicotine delivered when drawing on the device. Some cartridges were found to contain "tobacco-specific impurities suspected of being harmful to humans—anabasine, myosmine, and β-nicotyrine—were detected in a majority of the samples tested." 
In July 2009, the FDA publicly discouraged the use of electronic cigarettes and raised concerns that electronic cigarettes may be marketed to young people and lack appropriate health warnings.
The Electronic Cigarette Association criticized that the FDA testing was too "narrow to reach any valid and reliable conclusions.” Exponent, Inc., commissioned by NJOY to review the FDA's study in July 2009, objected to the FDA analysis of electronic cigarettes lacking comparisons to other FDA-approved nicotine replacement therapy products where similar levels of TSNA were detected. Exponent concluded that the FDA's study did not support the claims of potential adverse health effects from the use of electronic cigarettes.
Furthermore, FDA methods "have been lambasted in journals" by some medical and health research experts who noted the potentially harmful chemicals were measured at "about one million times lower concentrations than are conceivably related to human health.”
American Association of Public Health Physicians
As of April 2010, The American Association of Public Health Physicians (AAPHP) supports electronic cigarettes sales to adults, "because the possibility exists to save the lives of four million of the eight million current adult American smokers who will otherwise die of a tobacco-related illness over the next twenty years." However, the AAPHP is against sales to minors. The AAPHP recommends that the FDA reclassify the electronic cigarette as a tobacco product (as opposed to a drug/device combination).
Boston University School of Public Health study
A study by researchers at the Boston University School of Public Health in 2010 concluded that electronic cigarettes were safer than real cigarettes and may aid in breaking the habit of smoking. Researchers said that while further studies on electronic cigarettes were needed, "few, if any, chemicals at levels detected in electronic cigarettes raise serious health concerns." Electronic cigarettes were found to be "much safer" than traditional tobacco ones, and had a level of toxicity similar to existing nicotine replacements.
In the report, the level of carcinogens in electronic cigarettes was found to be up to 1,000 times lower than regular cigarettes. It also said early evidence shows that electronic cigarettes may help people to stop smoking by simulating a tobacco cigarette.
On 27 March 2009, Health Canada issued an advisory against electronic cigarettes. The advisory stated "Although these electronic smoking products may be marketed as a safer alternative to conventional tobacco products and, in some cases, as an aid to quitting smoking, electronic smoking products may pose risks such as nicotine poisoning and addiction."
Health New Zealand
In 2008, Dr. Murray Laugesen of Health New Zealand Ltd, published a report on the safety of Ruyan electronic cigarette cartridges funded by e-cigarette manufacturer, Ruyan; Laugesen and the WHO claim that the research is independent. The presence of trace amounts of TSNAs in the cartridge solution was documented in the analysis. The results also indicated that the level of nicotine in the electronic cigarette cartridges was not different from the concentration of nicotine found in nicotine patches. John Britton, a lung specialist at the University of Nottingham, UK and chair of the Royal College of Physicians Tobacco Advisory Group said “if the levels are as low as in nicotine replacement therapy, I don’t think there will be much of a problem.” The study's detailed quantitative analysis concluded that carcinogens and toxicants are present only below harmful levels. It concluded: "Based on the manufacturer’s information, the composition of the cartridge liquid is not hazardous to health, if used as intended."
A recent Greek study found that e-cigarettes are no threat to the heart. Dr Konstantinos Farsalinos from the Onassis Cardiac Surgery Center in Athens told the annual meeting of the European Society of Cardiology that "Electronic cigarettes are not a healthy habit but they are a safer alternative to tobacco cigarettes,"."Considering the extreme hazards associated with cigarette smoking, currently available data suggest that electronic cigarettes are far less harmful and substituting tobacco with electronic cigarettes may be beneficial to health." Farsalinos and his team examined the heart function of 20 young smokers before and after smoking one tobacco cigarette against that of 22 e-cigarette users before and after using the device for seven minutes. While the tobacco smokers suffered significant heart dysfunction, including raised blood pressure and heart rate, those using e-cigarettes had only a slight elevation in pressure. The Greek clinical study was the first in the world to look at the cardiac effects of e-cigarettes. Another small study, also in Greece, reported earlier this year the devices had little impact on lung function.
A report from a UK Government advisory unit favoured to adopt "smokeless nicotine cigarettes" instead of the traditional "quit or die" approach believing this would save more lives.
While electronic cigarettes are purported to deliver nicotine to the user in a manner similar to that of a nicotine inhaler, no electronic cigarette has yet been approved as a medicinal nicotine replacement therapy (NRT) product or provided the necessary clinical testing for such approval. Doubts have also been raised as to whether electronic cigarettes actually deliver any substantial amount of nicotine at all.
Research carried out at the University of East London on the effects of the use of an electronic cigarette to reduce cravings in regular tobacco smokers showed that there was no significant reported difference between smokers who inhaled vapour containing nicotine, and those who inhaled vapour containing no nicotine. The report concluded that although electronic cigarettes can be effective in reducing nicotine-related withdrawal symptoms, the nicotine content does not appear to be of central importance, and that other smoking related cues (such as taste, vapour resembling smoke) may account for the reduction in discomfort associated with tobacco abstinence in the short term.
In an online survey from November 2009 among 303 smokers, it was found that e-cigarette substitution for tobacco cigarettes resulted in reduced perceived health problems, when compared to smoking conventional cigarettes (less cough, improved ability to exercise, improved sense of taste and smell).
Because of the relative novelty of the technology and the possible relationship to tobacco laws and medical drug policies, electronic cigarette legislation and public health investigations are currently pending in many countries. As flavored tobacco cigarettes (except menthol) have been banned in the US, and roll-your-own (RYO) products are seeing massive increases in taxes (e.g., Iowa), electronic cigarettes remain a viable alternative to tobacco for many Americans.
The EU Directive 2001/95/EC(6) on general product safety, applies in so far as there are no specific provisions with the same objective in other EU law. This directive provides for restrictive or preventive measures to be taken if the product is found to be dangerous to the health and safety of consumers.
Whether electronic cigarettes could be regarded as falling under Directive 93/42/EEC on medical devices depends on the claimed intended use and whether this intended use has a medical purpose. "It is for each national authority to decide, account being taken of all the characteristics of the product, whether it falls within the definition of a medicinal product by its function or presentation."
Because of this vague EU position, member countries in the European Economic Area currently have varying rules.
United States of America
Individual states have differing legal treatment of electronic cigarettes.
On 22 September 2009, under the authorization of the Family Smoking Prevention and Tobacco Control Act, the FDA banned flavored tobacco (with the notable exception of menthol cigarettes) due to its potential appeal to children. Wagner says that the use of flavorings such as chocolate could encourage childhood use and serve as a gateway to cigarette smoking.
The Food and Drug Administration (FDA) classified electronic cigarettes as drug delivery devices and subject to regulation under the Food, Drug, and Cosmetic Act (FDCA) prior to importation to and sale in the United States. The classification was challenged in court, and overruled in January 2010 by Federal District Court Judge Richard J. Leon, citing that "the devices should be regulated as tobacco products rather than drug or medical products." Judge Leon ordered the FDA to stop blocking the importation of electronic cigarettes from China and indicated that the devices should be regulated as tobacco products rather than drug or medical devices.
In March 2010, a US Court of Appeal stayed the injunction pending an appeal, during which the FDA argued the right to regulate electronic cigarettes based on their previous ability to regulate nicotine replacement therapies such as nicotine gum or patches. Further, the agency argued that tobacco legislation enacted the previous year "expressly excludes from the definition of 'tobacco product' any article that is a drug, device or combination product under the FDCA, and provides that such articles shall be subject to regulation under the pre-existing FDCA provisions." On 7 December 2010, the appeals court ruled against the FDA in a 3–0 unanimous decision, ruling the FDA can only regulate electronic cigarettes as tobacco products, and thus cannot block their import. The judges ruled that such devices would only be subject to drug legislation if they are marketed for therapeutic use – E-cigarette manufacturers had successfully proven that their products were targeted at smokers and not at those seeking to quit. The District of Columbia Circuit appeals court declined to review the decision blocking the products from FDA regulation as medical devices on 24 January 2011.
Concerns about public safety have been raised. However, some former smokers say they have been helped by e-cigarettes, and scientists at the University of California, Berkeley said that e-cigarettes had great potential for reducing the morbidity and mortality related to smoking.
- In Austria nicotine-containing cartridges are classified as medicinal products and e-cigarettes for nicotine inhalation as medical devices.
- In the Czech Republic, the use, sale and advertising of electronic cigarettes is legal.
- In Denmark, the Danish Medicines Agency classifies electronic cigarettes containing nicotine as medicinal products. Thus, authorization is required before the product may be marketed and sold, and no such authorization has currently been given. The agency has clarified, however, that electronic cigarettes that do not administer nicotine to the user, and are not otherwise used for the prevention or treatment of disease, are not considered medicinal devices. The use of electronic cigarettes has not been prohibited in Copenhagen Airport, but at least one airline (Scandinavian Airlines) has decided to ban their use on board flights.
- In Finland, the National Supervisory Authority of Welfare and Health (Valvira) declared that the new tobacco marketing ban (effective 1.1.2012) will also cover electronic cigarettes, resulting in that Finnish stores or webstores can't advertise e-cigarettes because they might look like regular cigarettes. In theory, e-cigarettes with nicotine-free cartridges may still be sold, as long as their images and prices are not visible. Ordering from abroad remains allowed. Sale of nicotine cartridges is currently prohibited, as nicotine is considered a prescription drug requiring an authorization that such cartridges do not yet have. However, the Finnish authorities have decided that nicotine cartridges containing less than 10 mg nicotine, and e-liquid containing less than 0,42 g nicotine per bottle, may be legally brought in from other countries for private use. If the nicotine content is higher, a prescription from a Finnish physician is required. From a country within the European Economic Area a maximum of one year's supply may be brought in for private use when returning to Finland, while three months' supply may be brought in from outside the EEA. Mail order deliveries from EEA countries, for a maximum of three months' supply, are also allowed.
- In Germany, sale of electronic cigarettes and nicotine-containing cartridges is not forbidden. The electronic cigarette ban outspoken by the health minister of NRW on the press conference on 16 December 2011 is not a legally binding ban but merely exercised free speech.
- In Italy, by a Health Ministry decree (G.U. Serie Generale n. 232, 5 October 2011) electronic cigarettes containing nicotinine cannot be sold to individuals under 16 years old.
- In Latvia, the Ministry of Health has warned that the e-cigarette can cause harm to cardiovascular, hepatic and renal systems, however, e-cigarettes are legal, and are sold in most shopping centers and at Riga's airport, as well as via the internet to individuals at least 18 years old.
- In the Netherlands, use and sale of electronic cigarettes is allowed, but advertising is forbidden pending European Union legislation.
- In Norway electronic cigarettes and nicotine can only be imported from other EEA member states (e.g. the UK) for private use.
- In Poland, the sale and use of electronic cigarettes are legal.
- In Portugal, the sale and use of electronic cigarettes are legal.
- In the United Kingdom, the use, sale and advertising of electronic cigarettes is legal. Electronic cigarettes are also allowed to be smoked inside pubs, coffee shops, etc...
United States of America
- California Governor Arnold Schwarzenegger vetoed a bill that would regulate the sale of electronic cigarettes within the state on grounds that "if adults want to purchase and consume these products with an understanding of the associated health risks, they should be able to do so."
- In 2009, New Jersey voted to treat the electronic cigarette in the same category as tobacco products by including under the New Jersey Smoke Free Air Act. Assemblywoman Connie Wagner sponsored the legislation arguing that they "looked like the real thing"; she also objected to the potential appeal of flavored electric cigarettes to children.
- The sale of electronic cigarettes to minors in New Hampshire was legal. A group of students and a group called “Breathe New Hampshire” were concerned that electronic cigarettes will serve as a gateway to smoking cigarettes through appearing to be trendy: one compared electronic cigarettes to “having a new cell phone. It’s cool. It’s electronic.” They launched petitions to the state government to ban the sale of electronic cigarettes to minors. It is now illegal to sell e-cigarettes to minors as of July 2010.
- Arizona has a planned ban of selling electronic cigarettes to minors.
- In Washington, the King County board of health has banned smoking of electronic cigarettes in public places, and prohibited sales to minors. Neighboring Pierce County also prohibits sales to minors, but allows e-cigarette use in places such as bars and workplaces.
- In Maryland HB1272 was introduced by Delegate Aruna Miller and was passed by the General Assembly that bans the sale of electronic cigarettes to minors.
- In Oregon in February 2012, Continental Airlines flight 1118 was diverted back to its airport of origin when an unruly passenger with unspecified mental disorders refused to stop using his e-cigarette. The passenger was detained by fellow passengers and later plead guilt to charges of interfering with a flight crew. FAA had not ruled on E-cigarette use on airplanes at the time of the incident, but airlines were and are permitted to establish their own more-restrictive policies on E-cigarette use on planes; Continental (now United Airlines) has a company policy banning them 
- In Iowa in 2012, the Linn County commissioners approved a decision to regulate the retail sale of electronic cigarettes like tobacco cigarettes. As a result of this decision, retailers who sell electronic cigarettes to persons in Linn County are required to have a retail tobacco license.
- In Australia, the Federal Department of Health and Ageing classifies every form of nicotine, except for replacement therapies and cigarettes, as a form of poison. However, in the state of Victoria, the Therapeutic Goods Administration said there were no laws preventing the importation of e-cigarettes bought over the internet for personal use, unless prohibited by state and territory legislation.
- In Brazil, the sale, importation and advertisement of any kind of electronic cigarettes are forbidden. The Brazilian health and sanitation federal agency, Anvisa, found the current health safety assessments about e-cigarettes not to be yet satisfactory to make the product eligible to be approved for commercialization.
- In Canada, as of March 2009, the import, sale, and advertising of electronic cigarettes containing nicotine are banned in Canada, while non-nicotine e-cigs are legal and may be sold and advertised. Health Canada advised Canadian consumers not to purchase or use any electronic smoking products, cited prohibition of electronic smoking products containing nicotine in the Food and Drugs Act; no market authorization has been granted for any electronic smoking product.
- In China, the sale and use of electronic cigarettes are legal.
- In Hong Kong the sale and possession of nicotine-based electronic cigarette, classified as a Type I Poison, is govered under the Pharmacy and Poisons Ordinance. Sale or possession is not authorized and both considered are punishable with a fine of up to HK$100,000 and/or a prison term of 2 years. However, the law does not cover any non-nicotine inhaler.
- In India, the use of electronic cigarettes is currently legal. Under the Indian Health Law of 2006, tobacco smoking has been banned in public; though since e-cigarettes avoid the use of tobacco, they do not fall under this law.
- In Lebanon, the council of ministers has banned the sale and use of electronic cigarettes starting 21 September 2011.
- In Nepal, under the law of cigarette the use and sale of e cigarette is permitted.
- In New Zealand, the Ministry of Health has ruled that the Ruyan e-cigarette falls under the requirements of the Medicines Act, and cannot be sold except as a registered medicine. Since the ruling, Ruyan has obtained registration, and sale is currently allowed in pharmacies.
- In Panama, importation, distribution and sale have been prohibited since June 2009. The Ministry of Health cites the FDA findings as their reason for the ban.
- In Singapore, the sale and import of electronic cigarettes, even for personal consumption, is illegal. According to Health Minister Khaw Boon Wan, electronic cigarettes were the industry's attempt to attract new users and were marketed to appeal to younger customers, including women.
- In South Korea, the sale and use of electronic cigarettes are legal, but heavily taxed. Possessing electric cigarettes among teenagers is a problem.
- In Switzerland, sale of nicotine-free electronic cigarettes is legal. Use and import of electronic cigarettes containing nicotine is legal, though they cannot be sold in Switzerland. As of December 2011 the tobacco tax does not apply to e-cigarettes and respective liquids containing nicotine anymore.
- In the United Arab Emirates, sale and import of electronic cigarettes, even for personal consumption, is illegal. Items will be confiscated upon arrival.
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- Media related to Electronic cigarettes at Wikimedia Commons
- FDA information page on electronic cigarettes