Since entering the market around 2003, e-cigarette use has risen rapidly. [44] [45] [46] In 2011 there were about 7 million adult e-cigarette users globally, increasing to 68 million in 2020 compared with 1.1 billion cigarette smokers. [47] There was a further rise to 82 million e-cigarette users in 2021. [48] This increase has been attributed to targeted marketing, lower cost compared to conventional cigarettes, and the better safety profile of e-cigarettes compared to tobacco. [49] E-cigarette use is highest in China, the US, and Europe, with China having the most users. [6] [50] Motivation Reasons for initiating e-cigarette use in the European Union, in a 2018 Eurobarometer poll [51] British American Tobacco, through their subsidiary Nicoventures, licensed a nicotine delivery system based on existing asthma inhaler technology from UK-based healthcare company Kind Consumer. [398] In September 2014 a product based on this named Voke obtained approval from the United Kingdom's Medicines and Healthcare Products Regulatory Agency. [399] France's e-cigarette market was estimated by Groupe Xerfi to be €130 million in 2015. [393] Additionally, France's e-liquid market was estimated at €265 million. [393] In December 2015, there were 2,400 vape shops in France, 400 fewer than in March of the same year. [393] Industry organization Fivape said the reduction was due to consolidation, not to reduced demand. [393] Environmental impact Tobacco product waste

a b c d Bals, Robert; Boyd, Jeanette; Esposito, Susanna; Foronjy, Robert; Hiemstra, Pieter; Jiménez-Ruiz, Carlos A.; Katsaounou, Paraskevi; Lindberg, Anne; Metz, Carlos; Schober, Wolfgang; Spira, Avrum; Blasi, Francesco (February 2019). "Electronic cigarettes: a task force report from the European Respiratory Society". European Respiratory Journal. 53 (2): 1801151. doi: 10.1183/13993003.01151-2018. ISSN 0903-1936. PMID 30464018. S2CID 53711734. The long-term effects of ECIG use are unknown, and there is therefore no evidence that ECIGs are safer than tobacco in the long term. Based on current knowledge, negative health effects cannot be ruled out. The mixture used in vapor products such as e-cigarettes is called e-liquid. [33] E-liquid formulations vary widely. [27] [34] A typical e-liquid is composed of propylene glycol and glycerin (95%) and a combination of flavorings, nicotine, and other additives (5%). [35] [36] The flavorings may be natural, artificial, [34] or organic. [37] Over 80 harmful chemicals such as formaldehyde and metallic nanoparticles have been found in e-liquids at trace quantities. [38] There are many e-liquid manufacturers, [39] and more than 15,000 flavors. [40] a b Gibson, Laura A.; Creamer, MeLisa R.; Breland, Alison B.; Giachello, Aida Luz; Kaufman, Annette; Kong, Grace; Pechacek, Terry F.; Pepper, Jessica K.; Soule, Eric K.; Halpern-Felsher, Bonnie (2018). "Measuring perceptions related to e-cigarettes: Important principles and next steps to enhance study validity". Addictive Behaviors. 79: 219–225. doi: 10.1016/j.addbeh.2017.11.017. ISSN 0306-4603. PMC 5807230. PMID 29175027. The use of e-cigarettes for quitting smoking is controversial. [135] Limited evidence suggests that e-cigarettes probably do help people to stop smoking when used in clinical settings. [23] However, according to a review article by Hussein Traboulsi et al. in May 2020, a study by Dr Peter Hajek also resulted in more smokers becoming dual users than succeeded in complete abstinence; "Nonetheless, the continued use of and dependence on nicotine and the creation of dual users were issues in this trial...Additionally, while 18% of the e-cigarette users achieved complete abstinence, 25% (110/438) became dual users of e-cigarettes and conventional cigarettes." [136] Data regarding their use includes at least 26 randomized controlled trials [23] and a number of user surveys, case reports, and cohort studies. [137]

Consumers have shown passionate support for e-cigarettes that other nicotine replacement products did not receive. [119] They have a mass appeal that could challenge combustible tobacco's market position. [119] Critics of vaping bans state that vaping is a much safer alternative to smoking tobacco products and that vaping bans incentivize people to return to smoking cigarettes. [338] For example, critics cite the British Journal of Family Medicine in August 2015 which stated, "E-cigarettes are 95% safer than traditional smoking." [339] Additionally, San Francisco's chief economist, Ted Egan, when discussing the San Francisco vaping ban stated the city's ban on e-cigarette sales will increase smoking as vapers switch to combustible cigarettes. [340] Critics of smoking bans stress the absurdity of criminalizing the sale of a safer alternative to tobacco while tobacco continues to be legal. Prominent proponents of smoking bans are not in favor of criminalizing tobacco either, but rather allowing consumers to have the choice to choose whatever products they desire. [338] In 1927, Joseph Robinson applied for a patent for an electronic vaporizer to be used with medicinal compounds. [243] The patent was approved in 1930 but the device was never marketed. [244] In 1930, the United States Patent and Trademark Office reported a patent stating, "for holding medicinal compounds which are electrically or otherwise heated to produce vapors for inhalation." [245] In 1934 and 1936, further similar patents were applied for. [245] The ACS does not recommend the use of e-cigarettes as a cessation method. No e-cigarette has been approved by the Food and Drug Administration (FDA) as a safe and effective cessation product. The long-term risks of exclusive use of e-cigarettes are not fully known but evidence is accumulating that e-cigarette use has negative effects on the cardiovascular system and lungs. Without immediate measures to stop epidemic use of these products, the long-term adverse health effects will increase." [238]

a b Hedman, L; Galanti, MR; Ryk, L; Gilljam, H; Adermark, L (13 October 2021). "Electronic cigarette use and smoking cessation in cohort studies and randomized trials: A systematic review and meta-analysis". Tobacco Prevention and Cessation. European Network for Smoking and Tobacco Prevention. 7 (62): 62. doi: 10.18332/tpc/142320. PMC 8508281. PMID 34712864. Many US and Chinese e-cigarette makers copied his designs illegally, so Hon has not received much financial reward for his invention (although some US manufacturers have compensated him through out-of-court settlements). [261] Ruyan later changed its company name to Dragonite International Limited. [266] As of 2014, most e-cigarettes used a battery-powered heating element rather than the earlier ultrasonic technology design. [27] McNeill, A; Brose, LS; Calder, R; Bauld, L; Robson, D (February 2018). "Evidence review of e-cigarettes and heated tobacco products 2018" (PDF). Public Health England. UK. pp.1–243. A popular vaporizer named Juul was widely used by American young people until 2022, when the FDA banned its products from sale. [111] [112] Close to 80% of respondents in a 2017 Truth Initiative study aged 15–24 reported using Juul also used the device in the last 30 days. [113] In the 2010s, US teenagers used the verb "Juuling" to describe vaping, [114] and Juuling was the subject of widespread memes on social media. [115] Harm reduction Effects of vaping, compared to tobacco smoking [116] Long-term exposure to nicotine can also result in downregulation of glutamate transporter 1. [209] Long-term nicotine exposure upregulates cortical nicotinic receptors, but it also lowers the activity of the nicotinic receptors in the cortical vasodilation region. [210] These effects are not easily understood. [210] With constant use of nicotine, tolerance occurs at least partially as a result of the development of new nicotinic acetylcholine receptors in the brain. [206]The risk of early death is anticipated to be similar to that of smokeless tobacco. [172] Since vapor does not contain tobacco and does not involve combustion, users may avoid several harmful constituents usually found in tobacco smoke, [173] such as ash, tar, and carbon monoxide. [174] However, e-cigarette use with or without nicotine cannot be considered risk-free [175] because the long-term effects of e-cigarette use are unknown. [21] [162] [172] Possible side effects of nicotine [176]

a b Pepper, J. K.; Brewer, N. T. (2013). "Electronic nicotine delivery system (electronic cigarette) awareness, use, reactions and beliefs: a systematic review". Tobacco Control. 23 (5): 375–384. doi: 10.1136/tobaccocontrol-2013-051122. ISSN 0964-4563. PMC 4520227. PMID 24259045. Favor cigarettes were sold in California and several Southwestern states, marketed as "an alternative to smokers, and only to smokers, to use where smoking is unacceptable or prohibited." [255] In 1987 the FDA exercised jurisdiction over products analogous to E-Cigarettes. [256] Advanced Tobacco Products never challenged the Warning Letter and ceased all distribution of Favor. [257] Rays's wife Brenda Coffee coined the term vaping. [258] Philip Morris' division NuMark, launched in 2013 the MarkTen e-cigarette that Philip Morris had been working on since 1990. [242] Modern electronic cigarette: 2000s As of 8 August 2016, the US FDA extended its regulatory power to include e-cigarettes, e-liquid and all related products. [228] Under this ruling the FDA will evaluate certain issues, including ingredients, product features and health risks, as well their appeal to minors and non-users. [324] The FDA rule also bans access to minors. [324] A photo ID is now required to buy e-cigarettes, [325] and their sale in all-ages vending machines is not permitted in the US. [324] As of August 2017, regulatory compliance deadlines relating to premarket review requirements for most e-cigarette and e-liquid products have been extended from November 2017 to 8 August 2022, [326] [327] which attracted a lawsuit filed by the American Heart Association, American Academy of Pediatrics, the Campaign for Tobacco-Free Kids, and other plaintiffs. [328] Since 2016 the US Food and Drug Administration (US FDA) regulated e-cigarettes under the classification of tobacco products and labeled them as electronic nicotine delivery systems. [191] A 2018 report commissioned by the US FDA decided to use the term e-cigarettes, indicating that for some use e-liquids containing no nicotine. [191] Another common chemical found in e-cigarettes is ketene. When it enters the lungs after inhaled, this chemical causes damage to the cellular structure of lung tissue causing the cells to not function at maximum capacity and not absorb gasses as readily. This can cause shortness of breath which can lead to other health conditions such as tachycardia and respiratory failure. E-cigarette users who use devices that contain nicotine are exposed to its potentially harmful effects. [92]A small number of studies have looked at whether using e-cigarettes reduces the number of cigarettes smokers consume. [147] E-cigarette use may decrease the number of cigarettes smoked, [148] but smoking just one to four cigarettes daily greatly increases the risk of cardiovascular disease compared to not smoking. [83] The extent to which decreasing cigarette smoking with vaping leads to quitting is unknown. [149] A 2019 review concluded that, "no long term vaping toxicological/safety studies have been done in humans; without these data, saying with certainty that e-cigarettes are safer than combustible cigarettes is impossible." [95] While advertising of tobacco products is banned in most countries, television and radio e-cigarette advertising in several countries may be indirectly encouraging traditional cigarette use. [83] E-cigarette advertisements are also in magazines, newspapers, online, and in retail stores. [349] Between 2010 and 2014, e-cigarettes were second only to cigarettes as the top advertised product in magazines. [350] As cigarette companies have acquired the largest e-cigarette brands, they currently benefit from a dual market of smokers and e-cigarette users while simultaneously presenting themselves as agents of harm reduction. [124] This raises concerns about the appropriateness of endorsing a product that directly profits the tobacco industry. [124] There is no evidence that the cigarette brands are selling e-cigarettes as part of a plan to phase out traditional cigarettes, despite some stating to want to cooperate in "harm reduction". [83] E-cigarette advertising for using e-cigarettes as a quitting tool have been seen in the US, UK, and China, which have not been supported by regulatory bodies. [351]

Health and Care Excellence, The National Institute for (30 November 2021). "Recommendations on treating tobacco dependence Tobacco: preventing uptake, promoting quitting and treating dependence. Guidance NICE". www.nice.org.uk . Retrieved 13 November 2022. use of e‑cigarettes is likely to be substantially less harmful than smokingTobacco smoke contains 100 known carcinogens and 900 potentially cancer-causing chemicals, but e-cigarette vapor contains less of the potential carcinogens than found in tobacco smoke. [122] A study in 2015 using a third-generation device found levels of formaldehyde were greater than with cigarette smoke when adjusted to a maximum power setting. [123] E-cigarettes cannot be considered safe because there is no safe level for carcinogens. [118] Due to their similarity to traditional cigarettes, e-cigarettes could play a valuable role in tobacco harm reduction. [124] The public health community remains divided concerning the appropriateness of endorsing a device whose safety and efficacy for smoking cessation remain unclear. [124] Overall, the available evidence supports the cautionary implementation of harm reduction interventions aimed at promoting e-cigarettes as attractive and competitive alternatives to cigarette smoking, while taking measures to protect vulnerable groups and individuals. [124]