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Undid revision 638947681 by Doc James (talk)Stop this nonsense. The RfC found against your preferred order. Accept it and move on.
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[[File:Cig a like-- 2013-10-21 03-47.jpg|thumb|First generation electronic cigarette resembling a tobacco cigarette]]
[[File:Cig a like-- 2013-10-21 03-47.jpg|thumb|First generation electronic cigarette resembling a tobacco cigarette]]
<!-- Definition and Construction -->
<!-- Definition and Construction -->
An '''electronic cigarette''' ('''e-cig''' or '''e-cigarette'''), '''personal vaporizer''' ('''PV''') or '''electronic nicotine delivery system''' ('''ENDS''') is a [[battery (electricity)|battery]]-powered [[Vaporizer (inhalation device)|vaporizer]] which has a similar feel to [[tobacco smoking]].<ref name=Caponnetto2012>{{cite journal|last1=Caponnetto|first1=Pasquale|last2=Campagna|first2=Davide|last3=Papale|first3=Gabriella|last4=Russo|first4=Cristina|last5=Polosa|first5=Riccardo|title=The emerging phenomenon of electronic cigarettes|journal=Expert Review of Respiratory Medicine|volume=6|issue=1|year=2012|pages=63–74|issn=1747-6348|doi=10.1586/ers.11.92|pmid=22283580}}</ref> Electronic cigarettes do not contain [[tobacco]], although they do use [[nicotine]] from tobacco plants.<ref name=O2012/> They do not produce [[cigarette smoke]] but rather an [[aerosol]] (mist),<ref name=Grana2014/><ref name=Cheng2014>{{cite journal|last1=Cheng|first1=T.|title=Chemical evaluation of electronic cigarettes|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii11–ii17|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051482|pmc=3995255|pmid=24732157}}</ref> which is frequently but inaccurately referred to as [[vapor]].<ref name=Cheng2014/> In general, they have a [[heating element]] that atomizes a [[solution#Liquid solutions|liquid solution]] known as e-liquid.<ref name=Weaver2014>{{cite journal|last1=Weaver|first1=Michael|last2=Breland|first2=Alison|last3=Spindle|first3=Tory|last4=Eissenberg|first4=Thomas|title=Electronic Cigarettes|journal=Journal of Addiction Medicine|volume=8|issue=4|year=2014|pages=234–240|issn=1932-0620|doi=10.1097/ADM.0000000000000043|pmid=25089953}}</ref> E-liquids are usually a mixture of [[propylene glycol]], [[Glycerol|glycerin]], nicotine, and [[Flavor#Flavorants or flavorings|flavorings]].<ref name=Grana2014/> Others have similar ingredients but without nicotine.<ref name=Saitta2014/>
An '''electronic cigarette''' ('''e-cig''' or '''e-cigarette'''), '''personal vaporizer''' ('''PV''') or '''electronic nicotine delivery system''' ('''ENDS''') is a [[battery (electricity)|battery]]-powered [[Vaporizer (inhalation device)|vaporizer]] which has a similar feel to [[tobacco smoking]].<ref name=Caponnetto2012>{{cite journal|last1=Caponnetto|first1=Pasquale|last2=Campagna|first2=Davide|last3=Papale|first3=Gabriella|last4=Russo|first4=Cristina|last5=Polosa|first5=Riccardo|title=The emerging phenomenon of electronic cigarettes|journal=Expert Review of Respiratory Medicine|volume=6|issue=1|year=2012|pages=63–74|issn=1747-6348|doi=10.1586/ers.11.92|pmid=22283580}}</ref> Electronic cigarettes do not contain [[tobacco]], although they do use [[nicotine]] from tobacco plants.<ref name="O2012">{{cite journal|last=O'Connor|first=RJ|title=Non-cigarette tobacco products: what have we learnt and where are we headed?|journal=Tobacco control|date=March 2012|volume=21|issue=2|pages=181–90|pmid=22345243|doi=10.1136/tobaccocontrol-2011-050281|pmc=3716250}}</ref> They do not produce [[cigarette smoke]] but rather an [[aerosol]] (mist),<ref name="Grana2014">{{cite journal|last=Grana|first=R|author2=Benowitz, N |author3=Glantz, SA |title=E-cigarettes: a scientific review.|journal=Circulation|date=13 May 2014|volume=129|issue=19|pages=1972–86|pmid=24821826|doi=10.1161/circulationaha.114.007667|pmc=4018182}}</ref><ref name=Cheng2014>{{cite journal|last1=Cheng|first1=T.|title=Chemical evaluation of electronic cigarettes|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii11–ii17|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051482|pmc=3995255|pmid=24732157}}</ref> which is frequently but inaccurately referred to as [[vapor]].<ref name=Cheng2014/> In general, they have a [[heating element]] that atomizes a [[solution#Liquid solutions|liquid solution]] known as e-liquid.<ref name=Weaver2014>{{cite journal|last1=Weaver|first1=Michael|last2=Breland|first2=Alison|last3=Spindle|first3=Tory|last4=Eissenberg|first4=Thomas|title=Electronic Cigarettes|journal=Journal of Addiction Medicine|volume=8|issue=4|year=2014|pages=234–240|issn=1932-0620|doi=10.1097/ADM.0000000000000043|pmid=25089953}}</ref> E-liquids are usually a mixture of [[propylene glycol]], [[Glycerol|glycerin]], nicotine, and [[Flavor#Flavorants or flavorings|flavorings]].<ref name=Grana2014/> Others have similar ingredients but without nicotine.<ref name="Saitta2014">{{cite journal|last=Saitta|first=D|author2=Ferro, GA |author3=Polosa, R |title=Achieving appropriate regulations for electronic cigarettes.|journal=Therapeutic advances in chronic disease|date=Mar 2014|volume=5|issue=2|pages=50–61|pmid=24587890|doi=10.1177/2040622314521271|pmc=3926346}}</ref>


<!-- Health effects -->
<!-- Health effects -->
The [[Safety of electronic cigarettes|benefits and risks of electronic cigarette]] use are uncertain.<ref name=Odum2012/><ref name=Harrell2014/> One review found evidence of a benefit as a [[smoking cessation]] aid from a small number of studies.<ref name=Cochrane2014>{{cite journal|last1=McRobbie|first1=Hayden|last2=Bullen|first2=Chris|last3=Hartmann-Boyce|first3=Jamie|last4=Hajek|first4=Peter|last5=McRobbie|first5=Hayden|title=Electronic cigarettes for smoking cessation and reduction|journal=The Cochrane Library|year=2014|doi=10.1002/14651858.CD010216.pub2|pmid=25515689}}</ref> Another considered the data to be inconclusive.<ref name=Harrell2014/> Their role in [[tobacco harm reduction]] as a substitute for [[tobacco products]] is unclear.<ref name=Drummond2014/> They appear to be similar in safety to other [[nicotine replacement products]], but there is not enough data to draw conclusions.<ref name=Caponnetto2013/> The evidence suggests that the US [[Food and Drug Administration]] (FDA) accepted products such as a [[nicotine inhaler]] may be a safer way to give nicotine than e-cigarettes.<ref name=Drummond2014/>
The [[Safety of electronic cigarettes|benefits and risks of electronic cigarette]] use are uncertain.<ref name="Odum2012">{{cite journal|last1=Odum|first1=L. E.|last2=O'Dell|first2=K. A.|last3=Schepers|first3=J. S.|title=Electronic cigarettes: do they have a role in smoking cessation?|journal=Journal of pharmacy practice|date=December 2012|volume=25|issue=6|pages=611–4|pmid=22797832|doi=10.1177/0897190012451909}}</ref><ref name="Harrell2014">{{cite journal |last1=Harrell |first1=PT|last2=Simmons|first2=VN|last3=Correa|first3=JB|last4=Padhya|first4=TA|last5=Brandon|first5=TH|title=Electronic Nicotine Delivery Systems ("E-cigarettes"): Review of Safety and Smoking Cessation Efficacy.|journal=Otolaryngology—head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery|date= 4 June 2014|pmid=24898072|quote=These devices are unregulated, of unknown safety, and of uncertain benefit in quitting smoking.|doi=10.1177/0194599814536847}}</ref> One review found evidence of a benefit as a [[smoking cessation]] aid from a small number of studies.<ref name=Cochrane2014>{{cite journal|last1=McRobbie|first1=Hayden|last2=Bullen|first2=Chris|last3=Hartmann-Boyce|first3=Jamie|last4=Hajek|first4=Peter|last5=McRobbie|first5=Hayden|title=Electronic cigarettes for smoking cessation and reduction|journal=The Cochrane Library|year=2014|doi=10.1002/14651858.CD010216.pub2|pmid=25515689}}</ref> Another considered the data to be inconclusive.<ref name=Harrell2014/> Their role in [[tobacco harm reduction]] as a substitute for [[tobacco products]] is unclear.<ref name="Drummond2014">{{cite journal|last1=Drummond|first1=MB|last2=Upson|first2=D|title=Electronic cigarettes. Potential harms and benefits.|journal=Annals of the American Thoracic Society|date=February 2014|volume=11|issue=2|pages=236–42|pmid=24575993|doi=10.1513/annalsats.201311-391fr}}</ref> They appear to be similar in safety to other [[nicotine replacement products]], but there is not enough data to draw conclusions.<ref name="Caponnetto2013">{{cite journal|title=Electronic cigarette: a possible substitute for cigarette dependence.|journal=Monaldi archives for chest disease|date=Mar 2013|author1=Caponnetto P|author2=Russo C|author3=Bruno CM|author4=Alamo A|author5=Amaradio MD|author6=Polosa R.|volume=79|issue=1|pages=12–19|pmid=23741941}}</ref> The evidence suggests that the US [[Food and Drug Administration]] (FDA) accepted products such as a [[nicotine inhaler]] may be a safer way to give nicotine than e-cigarettes.<ref name=Drummond2014/>


<!-- Safety -->
<!-- Safety -->
The limited evidence suggests that e-cigarettes are safer than traditional [[cigarette]]s.<ref name=O2012/> Electronic cigarettes may carry a risk of addiction in those who do not already smoke,<ref name=WHOJuly2013/> but there is no evidence of ongoing use among those who have never smoked.<ref name=Hajek2014/> They may promote delaying of quitting smoking, or act as a deterrent to quitting.<ref name=Grana2014/> Emissions from e-cigarette may contain tiny [[ultrafine particle]]s of flavors, aroma transporters, glycerol, propylene glycol, nicotine, tiny amounts of [[carcinogen]]s and [[heavy metals]], and other chemicals.<ref name=Grana2014/><ref name=Hajek2014/> The evidence indicates the levels of contaminants do not warrant health concerns according to workplace safety standards.<ref name=Bur2014>{{cite journal|last1=Burstyn|first1=I|title=Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks.|journal=BMC Public Health|date=9 January 2014|volume=14|pages=18|pmid=24406205|doi=10.1186/1471-2458-14-18|pmc=3937158}}</ref> E-cigarette emissions have fewer [[toxic]] components than cigarette smoke.<ref name=Grana2014/> They are likely to be less harmful to users and bystanders.<ref name=Grana2014/><ref name=Hajek2014/> No serious adverse effects from e-cigarette have been reported in trials.<ref name=Cochrane2014/> Less serious [[adverse effect]]s from e-cigarette use include throat and mouth inflammation, vomiting, nausea, and cough.<ref name=Grana2014/>
The limited evidence suggests that e-cigarettes are safer than traditional [[cigarette]]s.<ref name=O2012/> Electronic cigarettes may carry a risk of addiction in those who do not already smoke,<ref name="WHOJuly2013">{{cite web|title=Tobacco Free Initiative (TFI)|url=https://web.archive.org/web/20130721131331/http://www.who.int/tobacco/communications/statements/eletronic_cigarettes/en|website=World Health Organization|date=9 July 2013}}</ref> but there is no evidence of ongoing use among those who have never smoked.<ref name="Hajek2014">{{cite journal|last1=Hajek|first1=P|last2=Etter|first2=JF|last3=Benowitz|first3=N|last4=Eissenberg|first4=T|last5=McRobbie|first5=H|title=Electronic cigarettes: review of use, content, safety, effects on smokers and potential for harm and benefit.|url=http://tobonline.com/Media/Default/Article/Addiction-%20Hajek%2014.pdf|journal=Addiction (Abingdon, England)|date=31 July 2014|pmid=25078252|doi=10.1111/add.12659|volume=109|issue=11|pages=1801–10}}</ref> They may promote delaying of quitting smoking, or act as a deterrent to quitting.<ref name=Grana2014/> Emissions from e-cigarette may contain tiny [[ultrafine particle]]s of flavors, aroma transporters, glycerol, propylene glycol, nicotine, tiny amounts of [[carcinogen]]s and [[heavy metals]], and other chemicals.<ref name=Grana2014/><ref name=Hajek2014/> The evidence indicates the levels of contaminants do not warrant health concerns according to workplace safety standards.<ref name=Bur2014>{{cite journal|last1=Burstyn|first1=I|title=Peering through the mist: systematic review of what the chemistry of contaminants in electronic cigarettes tells us about health risks.|journal=BMC Public Health|date=9 January 2014|volume=14|pages=18|pmid=24406205|doi=10.1186/1471-2458-14-18|pmc=3937158}}</ref> E-cigarette emissions have fewer [[toxic]] components than cigarette smoke.<ref name=Grana2014/> They are likely to be less harmful to users and bystanders.<ref name=Grana2014/><ref name=Hajek2014/> No serious adverse effects from e-cigarette have been reported in trials.<ref name=Cochrane2014/> Less serious [[adverse effect]]s from e-cigarette use include throat and mouth inflammation, vomiting, nausea, and cough.<ref name=Grana2014/>


<!-- Usage and History-->
<!-- Usage and History-->
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==Usage==
==Usage==
[[File:Bangor bilingual station no smoking sign.jpg|thumb|150px|left|thumb|Common reasons people use the e-cigarette is a desire to quit smoking cigarettes, cut down on their smoking habit or to circumvent [[smoke-free laws]].<ref name=Grana2014/>]]
[[File:Bangor bilingual station no smoking sign.jpg|thumb|150px|left|thumb|Common reasons people use the e-cigarette is a desire to quit smoking cigarettes, cut down on their smoking habit or to circumvent [[smoke-free laws]].<ref name=Grana2014/>]]
Electronic cigarette sales increased from 50,000 in 2008 to 3.5 million in 2012.<ref name=Sales2012/> Most people who use electronic cigarettes have a history of smoking cigarettes while some young people who have never smoked cigarettes have tried electronic cigarettes at least once.<ref name=Car2014/> Among adults or children, the extent to which a dual use tendency exists using e-cigarettes and traditional cigarettes is unclear.<ref name=Grana2014/> E-cigarette users most commonly continue to smoke traditional cigarettes.<ref name=Grana2014/> Many users report that electronic cigarettes help them either quit smoking or reduce the number of cigarettes smoked.<ref name=Hajek2014/> Adults most frequently use electronic cigarettes as a replacement for tobacco, but not always to quit.<ref name=Car2014/> Although some people have a desire to quit smoking by using e-cigarettes, other common explanations for the use of these products are to circumvent [[smoke-free laws]] and to cut back on traditional cigarettes.<ref name=Grana2014/> Many have conveyed concern about the possibility that e-cigarettes may function as a "gateway" to using traditional cigarettes.<ref name=Franck2014/> Ethical concerns exist from e-cigarettes use among minors and their possibility to weaken efforts to reduce traditional cigarette use.<ref name=Franck2014/>
Electronic cigarette sales increased from 50,000 in 2008 to 3.5 million in 2012.<ref name=Sales2012/> Most people who use electronic cigarettes have a history of smoking cigarettes while some young people who have never smoked cigarettes have tried electronic cigarettes at least once.<ref name=Car2014/> Among adults or children, the extent to which a dual use tendency exists using e-cigarettes and traditional cigarettes is unclear.<ref name=Grana2014/> E-cigarette users most commonly continue to smoke traditional cigarettes.<ref name=Grana2014/> Many users report that electronic cigarettes help them either quit smoking or reduce the number of cigarettes smoked.<ref name=Hajek2014/> Adults most frequently use electronic cigarettes as a replacement for tobacco, but not always to quit.<ref name=Car2014/> Although some people have a desire to quit smoking by using e-cigarettes, other common explanations for the use of these products are to circumvent [[smoke-free laws]] and to cut back on traditional cigarettes.<ref name=Grana2014/> Many have conveyed concern about the possibility that e-cigarettes may function as a "gateway" to using traditional cigarettes.<ref name="Franck2014">{{cite journal|last1=Franck|first1=C.|last2=Budlovsky|first2=T.|last3=Windle|first3=S. B.|last4=Filion|first4=K. B.|last5=Eisenberg|first5=M. J.|title=Electronic Cigarettes in North America: History, Use, and Implications for Smoking Cessation|journal=Circulation|volume=129|issue=19|year=2014|pages=1945–1952|issn=0009-7322|doi=10.1161/CIRCULATIONAHA.113.006416|pmid=24821825}}</ref> Ethical concerns exist from e-cigarettes use among minors and their possibility to weaken efforts to reduce traditional cigarette use.<ref name=Franck2014/>


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<!-- Youth -->
<!-- Youth -->
Larger numbers of young people are starting to use e-cigarettes.<!-- <ref name=Grana2014/> --> A high number of youths who use e-cigarettes also smoking traditional cigarettes.<!-- <ref name=Grana2014/> --> Some youths who have tried an e-cigarette have never smoked a traditional cigarette; this indicates that they can be a starting point for nicotine use for some youths.<!-- <ref name=Grana2014/> --> There are high levels of dual use with e-cigarettes and traditional cigarettes.<ref name=Grana2014/>
Larger numbers of young people are starting to use e-cigarettes.<!-- <ref name=Grana2014/> --> A high number of youths who use e-cigarettes also smoking traditional cigarettes.<!-- <ref name=Grana2014/> --> Some youths who have tried an e-cigarette have never smoked a traditional cigarette; this indicates that they can be a starting point for nicotine use for some youths.<!-- <ref name=Grana2014/> --> There are high levels of dual use with e-cigarettes and traditional cigarettes.<ref name=Grana2014/>

==Health effects==
===Position of medical organizations===
{{Main|Positions of medical organizations regarding electronic cigarettes}}
{{Asof|2014}} electronic cigarettes have not been approved for helping people quit smoking by any government.<ref name=WHOPosition2014/> In July 2014, a report produced by the [[World Health Organization]] (WHO) for the Conference of the Parties to the [[WHO Framework Convention on Tobacco Control]], found there was not enough evidence to determine if electronic cigarettes can help people quit smoking.<!-- <ref name=WHOPosition2014/> --> It suggested that smokers should be encouraged to use approved methods for help with quitting.<ref name=WHOPosition2014/> 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.<ref name=WHOPosition2014>{{cite web|last1=WHO|title=Electronic nicotine delivery systems|url=http://apps.who.int/gb/fctc/PDF/cop6/FCTC_COP6_10-en.pdf|accessdate=28 August 2014}}</ref> A previous WHO statement from July 2013 stated that e-cigarettes have not been shown to be effective helping people quit smoking.<ref name=WHOJuly2013>{{cite web|title=Tobacco Free Initiative (TFI)|url=https://web.archive.org/web/20130721131331/http://www.who.int/tobacco/communications/statements/eletronic_cigarettes/en|website=World Health Organization|date=9 July 2013}}</ref> 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.<ref name=WHOJuly2013/> The [[World Lung Foundation]] applauded the 2014 WHO report's recommendation for tighter regulation of e-cigarettes due to concerns about the safety of e-cigarettes and the possible increased nicotine or tobacco addiction among youth.<ref>{{cite web|title=WHO Right to Call for E-Cigarette Regulation|url=http://www.worldlungfoundation.org/ht/d/ReleaseDetails/i/32757|publisher=World Lung Federation|accessdate=6 November 2014}}</ref>

The UK [[National Health Service]] has concluded, "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."<ref>{{cite web|title=Stop smoking treatments|url=http://www.nhs.uk/Conditions/Smoking-%28quitting%29/Pages/Treatment.aspx|publisher=UK National Health Service|accessdate=6 November 2014}}</ref>

In 2014, the US [[Food and Drug Administration]] (FDA) concluded, "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."<ref>{{cite web|title=Electronic Cigarettes (e-Cigarettes)|url=http://www.fda.gov/NewsEvents/PublicHealthFocus/ucm172906.htm|publisher=US Food and Drug Administration|accessdate=6 November 2014}}</ref>

===Smoking cessation===

{{Asof|2014}}, research on the safety and efficacy of e-cigarette use for [[smoking cessation]] is limited.<ref name=Franck2014>{{cite journal|last1=Franck|first1=C.|last2=Budlovsky|first2=T.|last3=Windle|first3=S. B.|last4=Filion|first4=K. B.|last5=Eisenberg|first5=M. J.|title=Electronic Cigarettes in North America: History, Use, and Implications for Smoking Cessation|journal=Circulation|volume=129|issue=19|year=2014|pages=1945–1952|issn=0009-7322|doi=10.1161/CIRCULATIONAHA.113.006416|pmid=24821825}}</ref> Their benefit in helping people quit smoking is uncertain.<ref name=Harrell2014>{{cite journal |last1=Harrell |first1=PT|last2=Simmons|first2=VN|last3=Correa|first3=JB|last4=Padhya|first4=TA|last5=Brandon|first5=TH|title=Electronic Nicotine Delivery Systems ("E-cigarettes"): Review of Safety and Smoking Cessation Efficacy.|journal=Otolaryngology—head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery|date= 4 June 2014|pmid=24898072|quote=These devices are unregulated, of unknown safety, and of uncertain benefit in quitting smoking.|doi=10.1177/0194599814536847}}</ref> A 2014 [[Cochrane review]] found that e-cigarettes can help people quit, but was based on a small number of studies.<ref name=Cochrane2014/>

Two 2014 reviews found no evidence that e-cigarettes are more effective than existing nicotine replacement treatments for smoking cessation.<ref name=Drummond2014/><ref name=Cochrane2014/> One of these reviews stated that to encourage e-cigarette use as a cessation aid in cigarette users is premature.<ref name=Drummond2014/> A 2013 [[randomized controlled trial]] found higher smoking cessation rates associated with e-cigarettes with nicotine than e-cigarettes without nicotine or traditional NRT patches, but the study was too small to make these results statistically significant.<ref name=Polosa2013>{{citation|first=Riccardo |last=Polosa|first2=Brad|last2=Rodu|author3-first=Pasquale|author3-last=Caponnetto|author4-first=Marilena |author4-last=Maglia|author5-first=Cirino |author5-last=Raciti|journal=Harm Reduction Journal| volume=10|issue=10|title=A fresh look at tobacco harm reduction: the case for the electronic cigarette |year=2013|url=http://www.biomedcentral.com/content/pdf/1477-7517-10-19.pdf|pmid=24090432|doi=10.1186/1477-7517-10-19}}</ref> There are some [[non-controlled studies]] which have reported possible benefit.<ref name=Caponnetto2013>{{cite journal|title=Electronic cigarette: a possible substitute for cigarette dependence.|journal=Monaldi archives for chest disease|date=Mar 2013|author1=Caponnetto P|author2=Russo C|author3=Bruno CM|author4=Alamo A|author5=Amaradio MD|author6=Polosa R.|volume=79|issue=1|pages=12–19|pmid=23741941}}</ref> Electronic cigarettes were not regularly associated with trying to quit tobacco among young people.<ref name=Car2014/> 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.<ref name=Pisinger2014/> This review therefore called for their use to be limited to smokers who are unwilling or unable to quit.<ref name=Pisinger2014>{{cite journal|last1=Pisinger|first1=Charlotta|last2=Døssing|first2=Martin|title=A systematic review of health effects of electronic cigarettes|journal=Preventive Medicine|date=December 2014|volume=69|pages=248–260|doi=10.1016/j.ypmed.2014.10.009}}</ref> A 2014 review found four experimental studies and six cohort studies that indicated that electronic cigarettes reduced the desire to smoke and withdrawal symptoms.<ref name=Gualano2014/> This review also noted that two cohort studies found that electronic cigarettes led to a reduction in the number of cigarettes smoked per day.<ref name=Gualano2014>{{cite journal|last1=Gualano|first1=M. R.|last2=Passi|first2=S.|last3=Bert|first3=F.|last4=La Torre|first4=G.|last5=Scaioli|first5=G.|last6=Siliquini|first6=R.|title=Electronic cigarettes: assessing the efficacy and the adverse effects through a systematic review of published studies|journal=Journal of Public Health|date=9 August 2014|doi=10.1093/pubmed/fdu055|pmid=25108741}}</ref>

=== Harm reduction ===
[[Tobacco harm reduction]] has been a controversial area of tobacco control.<ref name=Cahn2011>{{cite journal |last1= M. |first1=Z. |last2=Siegel |title=Electronic cigarettes as a harm reduction strategy for tobacco control: a step forward or a repeat of past mistakes? |journal=Journal of public health policy |date=February 2011 |volume=32 |issue=1 |pages=16–31 |pmid=21150942 |doi= 10.1057/jphp.2010.41 |first2= M}}</ref> The health community have been cautious to support the [[tobacco industry]] to bring safer products to market that will lessen the risks related with tobacco use.<ref name=Cahn2011/> A 2011 review found in the fight to decrease tobacco related death and disease, e-cigarettes show great promise.<ref name=Cahn2011/> A 2014 review found no long-term evidence on the safety or efficacy of e-cigarettes, including whether they reduce harm for tobacco related disease or will improve the health of the population as a whole.<!-- <ref name=Drummond2014/> --> Therefore, promotion of e-cigarettes as a harm reduction product is premature.<ref name=Drummond2014>{{cite journal|last1=Drummond|first1=MB|last2=Upson|first2=D|title=Electronic cigarettes. Potential harms and benefits.|journal=Annals of the American Thoracic Society|date=February 2014|volume=11|issue=2|pages=236–42|pmid=24575993|doi=10.1513/annalsats.201311-391fr}}</ref> A 2014 review found e-cigarettes may be less harmful than tobacco cigarettes to users and bystanders.<ref name=Hajek2014/> The same review concluded that health professionals may consider advising smokers who are reluctant to quit by way of other methods to switch to e-cigarettes as a safer alternative to smoking.<ref name=Hajek2014/> A 2014 review argued that regulations for electronic cigarettes should be similar to those for dietary supplements or cosmetic products to not limit the potential for harm reduction with electronic cigarettes replacing tobacco.<ref name=Saitta2014>{{cite journal|last=Saitta|first=D|author2=Ferro, GA |author3=Polosa, R |title=Achieving appropriate regulations for electronic cigarettes.|journal=Therapeutic advances in chronic disease|date=Mar 2014|volume=5|issue=2|pages=50–61|pmid=24587890|doi=10.1177/2040622314521271|pmc=3926346}}</ref> 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.<ref name=O2012/> 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.<ref name=Caponnetto2012/>

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 mist of e-cigarettes.<ref name=Cahn2011/> 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.<ref name=Cahn2011/> 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.<ref name=FarsalinosPolosa2014>{{cite journal|last1=Farsalinos|first1=K. E.|last2=Polosa|first2=R.|title=Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes: a systematic review|journal=Therapeutic Advances in Drug Safety|volume=5|issue=2|year=2014|pages=67–86|issn=2042-0986|doi=10.1177/2042098614524430|pmc=4110871|pmid=25083263}}</ref> Adults most frequently use electronic cigarettes as a replacement for tobacco, but not always to quit.<ref name=Car2014/> 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.<ref name=Grana2014>{{cite journal|last=Grana|first=R|author2=Benowitz, N |author3=Glantz, SA |title=E-cigarettes: a scientific review.|journal=Circulation|date=13 May 2014|volume=129|issue=19|pages=1972–86|pmid=24821826|doi=10.1161/circulationaha.114.007667|pmc=4018182}}</ref> Some users want to reduce harm from smoking.<ref name=NHE2014/>

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.<ref name=NHE2014>{{cite web|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/311887/Ecigarettes_report.pdf|title=Electronic cigarettes – A report commissioned by Public Health England |publisher=[[Public Health England]]|date=15 May 2014|author1-first=John |author1-last=Britton|author2-first=Ilze|author2-last=Bogdanovica}}</ref> 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.<ref name=BMAhandout2013>{{cite web|title=BMA calls for stronger regulation of e-cigarettes|url=http://bma.org.uk/-/media/Files/PDFs/Working%20for%20change/Improving%20health/tobaccoecigarettespublicplaces_jan2013.pdf|publisher=British Medical Association|accessdate=18 November 2013}}</ref> 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.<ref>{{cite web |title=Principles to Guide AAPHP Tobacco Policy |url=http://www.aaphp.org/tobacco|work=American Association of Public Health Physicians |accessdate=31 July 2013}}</ref> 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.<!-- <ref name=CDCQ&A/> --> 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.<ref name=CDCQ&A>{{cite web |author=Edgar, Julie |title=E-Cigarettes: Expert Q&A With the CDC |url=http://www.webmd.com/smoking-cessation/news/20131112/e-cigarettes-cdc |publisher=WebMD |accessdate=17 November 2013}}</ref> 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.<!-- <ref name=WHOPosition2014/> --> 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."<ref name=WHOPosition2014/>

=== Safety ===
{{Main|Safety of electronic cigarettes}}
The risks of electronic cigarette use are uncertain.<ref name=Odum2012>{{cite journal|last1=Odum|first1=L. E.|last2=O'Dell|first2=K. A.|last3=Schepers|first3=J. S.|title=Electronic cigarettes: do they have a role in smoking cessation?|journal=Journal of pharmacy practice|date=December 2012|volume=25|issue=6|pages=611–4|pmid=22797832|doi=10.1177/0897190012451909}}</ref><ref name=Harrell2014/> This is due to there being little data regarding their [[health effect]]s<ref name=Palazzolo>{{Citation | title=Electronic cigarettes and vaping: a new challenge in clinical medicine and public health. A literature review. | url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3859972/ | author1-first=Dominic L. |author1-last=Palazzolo | journal=Frontiers in Public Health | volume=1 |issue=56 | date=Nov 2013| doi=10.3389/fpubh.2013.00056 | pmid=24350225 | pmc=3859972}}</ref> and to the variability of vaporizers and variability in liquid ingredients and in their concentration and quality, and thus variability of the contents of mist delivered to the user.<ref name=O2012>{{cite journal|last=O'Connor|first=RJ|title=Non-cigarette tobacco products: what have we learnt and where are we headed?|journal=Tobacco control|date=March 2012|volume=21|issue=2|pages=181–90|pmid=22345243|doi=10.1136/tobaccocontrol-2011-050281|pmc=3716250}}</ref><ref name=Grana2014/><ref name=Odum2012/> The limited evidence suggests that e-cigarettes are probably safer than traditional [[cigarette]]s.<ref name=O2012/>

They appear to be similar in [[toxicity]] to other [[nicotine replacement products]], but there is not enough data to draw conclusions.<ref name=Caponnetto2013/> The evidence suggests that the US [[Food and Drug Administration]] (FDA) accepted products such as a [[nicotine inhaler]] may be a safer way to give nicotine than e-cigarettes.<ref name=Drummond2014/> A July 2014 WHO report cautioned about potential risks of using electronic cigarettes.<!-- <ref name=WHOPosition2014/> --> 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."<ref name=WHOPosition2014/> A 2014 [[systematic review]] concluded that the risks of e-cigarettes have been exaggerated by health authorities and stated that it is apparent that there may be some remaining risk accompanied with e-cigarette use, though the risk of e-cigarette use is likely small compared to smoking tobacco.<ref name=FarsalinosPolosa2014/> {{Asof|2014}}, e-cigarettes cannot be regarded as harmless.<ref name=Pisinger2014/> Until additional data is available on the topic, using e-cigarettes cannot be regarded as safe.<ref name=Bertholon2013>{{cite journal|last1=Bertholon|first1=J.F.|last2=Becquemin|first2=M.H.|last3=Annesi-Maesano|first3=I.|last4=Dautzenberg|first4=B.|title=Electronic Cigarettes: A Short Review|journal=Respiration|year=2013|issn=1423-0356|doi=10.1159/000353253|pmid=24080743}}</ref> No long-term studies have shown that e-cigarettes are a "healthier alternative" to traditional cigarettes.<ref name=Drummond2014/> A 2014 review found no serious adverse effects reported in trials.<ref name=Cochrane2014/>

===Addiction===
A number of organizations have concerns that e-cigarettes might increase addiction to and use of nicotine and tobacco products in the young.<ref name=MMWR2013>{{cite journal|last=Centers for Disease Control and Prevention|first=(CDC)|title=Notes from the field: electronic cigarette use among middle and high school students – United States, 2011–2012|url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6235a6.htm |journal=MMWR. Morbidity and mortality weekly report|date=6 September 2013|volume=62|issue=35|pages=729–30|pmid=24005229}}</ref><ref name=DrugFacts2014>{{cite web|title=DrugFacts: Electronic Cigarettes (e-Cigarettes)|url=http://www.drugabuse.gov/publications/drugfacts/electronic-cigarettes-e-cigarettes|work=National Institute on Drug Abuse|accessdate=15 October 2014|date=September 2014|quote=There is also the possibility that they could perpetuate the nicotine addiction and thus interfere with quitting.}}</ref><ref>{{cite web|title=Citing Health Concerns the American Cancer Society Calls for Action|url=http://www.cancer.org/myacs/eastern/areahighlights/cancernynj-news-ny-ecig-health-vote|work=American Cancer Society|accessdate=12 November 2013|quote=Government agencies and medical organizations, such as the FDA, the Centers for Disease Control and Prevention, and the American Academy of Pediatrics have also expressed concern that electronic cigarettes could increase nicotine addiction and tobacco use in young people.}}</ref> This including: 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.<ref name=CDCQ&A/><ref name=IUATLD>{{cite web |title=Position Statement on Electronic Cigarettes [ECs] or Electronic Nicotine Delivery Systems [ENDS] |url=http://www.theunion.org/what-we-do/publications/official/body/E-cigarette_statement_FULL.pdf |format=PDF |date=October 2013 |publisher=The International Union against Tuberculosis and Lung Disease}}</ref><ref>{{cite web|last=Korioth|first=Trisha|title=E-cigarettes easy to buy, can hook kids on nicotine|url=http://aapnews.aappublications.org/content/early/2013/10/04/aapnews.20131004-4|work=The American Academy of Pediatrics|accessdate=17 November 2013}}</ref><ref name=FDAConsumer2009>{{cite web|title=FDA Warns of Health Risks Posed by E-Cigarettes|url=http://www.fda.gov/forconsumers/consumerupdates/ucm173401.htm|work=FDA|accessdate=17 November 2013|date=23 July 2009|postscript=—Reviewed 17 September 2013}}</ref> The World Health Organization raised concern of addiction for nonsmokers from their use in July 2013.<ref name=WHOJuly2013/> The [[National Institute on Drug Abuse]] stated that there is a possibility that they could promote continuation of addiction to nicotine in those who are attempting to quit.<ref name=DrugFacts2014/>

[[File:Nicotine-2D-skeletal.png|thumb|The [[nicotine]] [[molecule]].]]
It is not clear whether using e-cigarettes will decrease or increase overall [[nicotine addiction]].<ref name=Palazzolo/> The information concerning the drug action of the nicotine in e-cigarettes is limited.<ref name=Schroeder2014/> The evidence suggests that the nicotine in e-cigarettes is adequate to sustain nicotine dependence.<ref name=Schroeder2014>{{cite journal|last1=Schroeder|first1=M. J.|last2=Hoffman|first2=A. C.|title=Electronic cigarettes and nicotine clinical pharmacology|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii30–ii35|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051469|pmid=24732160}}</ref> The limited data suggests that the likelihood of abuse from e-cigarettes could be smaller compared to traditional cigarettes.<ref name=Evans2014>{{cite journal|last1=Evans|first1=S. E.|last2=Hoffman|first2=A. C.|title=Electronic cigarettes: abuse liability, topography and subjective effects|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii23–ii29|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051489|pmid=24732159}}</ref> A 2014 systematic review found that e-cigarettes could cause non-smokers to begin smoking are unsubstantiated.<ref name=FarsalinosPolosa2014/> A 2014 review found no evidence that they are used regularly by those who have never smoked,<ref name=Hajek2014>{{cite journal|last1=Hajek|first1=P|last2=Etter|first2=JF|last3=Benowitz|first3=N|last4=Eissenberg|first4=T|last5=McRobbie|first5=H|title=Electronic cigarettes: review of use, content, safety, effects on smokers and potential for harm and benefit.|url=http://tobonline.com/Media/Default/Article/Addiction-%20Hajek%2014.pdf|journal=Addiction (Abingdon, England)|date=31 July 2014|pmid=25078252|doi=10.1111/add.12659|volume=109|issue=11|pages=1801–10}}</ref> while a 2014 review has found that in some populations nearly up to a third of youth who have ever used electronic cigarettes have never smoked traditional cigarettes.<ref name=Grana2014/> No long-term studies have been done on the effectiveness of e-cigarettes in treating tobacco addiction.<ref name=Drummond2014/> The degree to which teens are using e-cigarettes in ways it is not intended to be used, such as increasing the nicotine delivery, is unknown.<ref name=Durmowicz2014>{{cite journal|last1=Durmowicz|first1=E. L.|title=The impact of electronic cigarettes on the paediatric population|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii41–ii46|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051468|pmid=24732163}}</ref> The extent to which e-cigarette use will lead to abuse in youth is unknown.<ref name=Durmowicz2014/> The impact of e-cigarette use by children in respect to [[substance dependence]] is unknown.<ref name=Durmowicz2014/>


== Construction ==
== Construction ==
[[File:Components of a MiniCiggy e-cigarette.jpg|thumb|Disassembled cigarette-styled electronic cigarette.<br />A. [[Light-emitting diode|LED]] light cover<br />B. [[battery (electricity)|battery]] (also houses circuitry)<br />C. atomizer (heating element)<br />D. cartridge (mouthpiece)]]
[[File:Components of a MiniCiggy e-cigarette.jpg|thumb|Disassembled cigarette-styled electronic cigarette.<br />A. [[Light-emitting diode|LED]] light cover<br />B. [[battery (electricity)|battery]] (also houses circuitry)<br />C. atomizer (heating element)<br />D. cartridge (mouthpiece)]]


Most electronic cigarettes take an overall cylindrical shape although a wide array of shapes can be found: box, pipe styles etc.<ref>{{cite web|last1=WHO|title=Electronic cigarettes (e-cigarettes) or electronic nicotine delivery systems|url=http://www.who.int/tobacco/communications/statements/eletronic_cigarettes/en/}}</ref> First generation electronic cigarettes were usually designed to simulate smoking implements, such as cigarettes or cigars, in their use and appearance.<ref name=Farsalinos2014>{{cite journal | author = Farsalinos KE, Spyrou A, Tsimopoulou K, Stefopoulos C, Romagna G, Voudris V | title = Nicotine absorption from electronic cigarette use: Comparison between first and new-generation devices | journal = Scientific Reports | volume = 4 | pages = 4133 | year = 2014 | pmid = 24569565 | pmc = 3935206 | doi = 10.1038/srep04133 }}</ref> New generation electronic cigarettes often called mods, PVs (personal vaporizer) or APVs (advanced personal vaporizer) have an increased nicotine-dispersal performance,<ref name=Farsalinos2014/> housing higher capacity batteries,<ref name=mcqueen2011/> and come in various form factors, including metal tubes and boxes.<ref name=mcqueen2011>{{Cite journal|pmid=21571692|doi=10.1093/ntr/ntr088|journal=Nicotine & Tobacco Research|year=2011|volume=13|issue=9|title=Interviews with "vapers": implications for future research with electronic cigarettes|url=http://www.stop-tabac.ch/fra/images/stories/documents_stop_tabac/interview%20with%20vapers.pdf|last2=Tower|author3-last=Sumner|first=Amy|last=McQueen|first2=Stephanie|first3=Walton|pages=860–7}}</ref><ref>{{cite web|url=http://www.lasvegassun.com/news/2013/oct/18/faqs-about-electronic-cigarettes/ |title=FAQs about electronic cigarettes – Las Vegas Sun News |publisher=[[Las Vegas Sun]] |accessdate=20 November 2013}}</ref><ref>{{cite web|url=http://www.stgeorgeutah.com/news/archive/2013/10/07/da-vaping-nicotine-gadget-craze-reaches-southern-utah/ |title=Vaping; nicotine gadget craze reaches Southern Utah |publisher=St George News |accessdate=20 November 2013}}</ref> An e-cigarette can be rigid and a bit bulky.<ref name=Caponnetto2012/> Many electronic cigarettes are composed of standardized replaceable parts that are interchangeable from one brand to the other.<ref>http://www.clubic.com/materiel-informatique/article-704447-1-cigarette-electronique.html%7C</ref> Common components include a liquid delivery and container system like tanks or cartomizers, an atomizer, and a power source.<ref name=howstuffworks>{{cite web|last=Cassidy |first=Susan |url=http://science.howstuffworks.com/innovation/everyday-innovations/electronic-cigarette1.htm |title=HowStuffWorks "How Electronic Cigarettes Work" |publisher=Science.howstuffworks.com |date=26 October 2011 |accessdate=27 August 2013}}</ref> A wide array of component combinations exist .<ref name=digitaltrends.com>{{cite web|last=Couts |first=Andrew |url=http://www.digitaltrends.com/features/inside-the-world-of-vapers-the-subculture-that-might-save-smokers-lives/ |title=Inside the world of vapers, the subculture that might save smokers' lives |publisher=[[Digital Trends]] |date=13 May 2013 |accessdate=20 November 2013}}</ref>
Most electronic cigarettes take an overall cylindrical shape although a wide array of shapes can be found: box, pipe styles etc.<ref>{{cite web|last1=WHO|title=Electronic cigarettes (e-cigarettes) or electronic nicotine delivery systems|url=http://www.who.int/tobacco/communications/statements/eletronic_cigarettes/en/}}</ref> First generation electronic cigarettes were usually designed to simulate smoking implements, such as cigarettes or cigars, in their use and appearance.<ref name="Farsalinos2014">{{cite journal | author = Farsalinos KE, Spyrou A, Tsimopoulou K, Stefopoulos C, Romagna G, Voudris V | title = Nicotine absorption from electronic cigarette use: Comparison between first and new-generation devices | journal = Scientific Reports | volume = 4 | pages = 4133 | year = 2014 | pmid = 24569565 | pmc = 3935206 | doi = 10.1038/srep04133 }}</ref> New generation electronic cigarettes often called mods, PVs (personal vaporizer) or APVs (advanced personal vaporizer) have an increased nicotine-dispersal performance,<ref name="Farsalinos2014" /> housing higher capacity batteries,<ref name="mcqueen2011" /> and come in various form factors, including metal tubes and boxes.<ref name="mcqueen2011">{{Cite journal|pmid=21571692|doi=10.1093/ntr/ntr088|journal=Nicotine & Tobacco Research|year=2011|volume=13|issue=9|title=Interviews with "vapers": implications for future research with electronic cigarettes|url=http://www.stop-tabac.ch/fra/images/stories/documents_stop_tabac/interview%20with%20vapers.pdf|last2=Tower|author3-last=Sumner|first=Amy|last=McQueen|first2=Stephanie|first3=Walton|pages=860–7}}</ref><ref>{{cite web|url=http://www.lasvegassun.com/news/2013/oct/18/faqs-about-electronic-cigarettes/ |title=FAQs about electronic cigarettes – Las Vegas Sun News |publisher=[[Las Vegas Sun]] |accessdate=20 November 2013}}</ref><ref>{{cite web|url=http://www.stgeorgeutah.com/news/archive/2013/10/07/da-vaping-nicotine-gadget-craze-reaches-southern-utah/ |title=Vaping; nicotine gadget craze reaches Southern Utah |publisher=St George News |accessdate=20 November 2013}}</ref> An e-cigarette can be rigid and a bit bulky.<ref name="Caponnetto2012" /> Many electronic cigarettes are composed of standardized replaceable parts that are interchangeable from one brand to the other.<ref>http://www.clubic.com/materiel-informatique/article-704447-1-cigarette-electronique.html%7C</ref> Common components include a liquid delivery and container system like tanks or cartomizers, an atomizer, and a power source.<ref name="howstuffworks">{{cite web|last=Cassidy |first=Susan |url=http://science.howstuffworks.com/innovation/everyday-innovations/electronic-cigarette1.htm |title=HowStuffWorks "How Electronic Cigarettes Work" |publisher=Science.howstuffworks.com |date=26 October 2011 |accessdate=27 August 2013}}</ref> A wide array of component combinations exist .<ref name="digitaltrends.com">{{cite web|last=Couts |first=Andrew |url=http://www.digitaltrends.com/features/inside-the-world-of-vapers-the-subculture-that-might-save-smokers-lives/ |title=Inside the world of vapers, the subculture that might save smokers' lives |publisher=[[Digital Trends]] |date=13 May 2013 |accessdate=20 November 2013}}</ref>


===Device generations===
===Device generations===
Line 78: Line 44:
====First generation====
====First generation====
[[File:Cigarrillo electronico funcionando.jpg|thumb|Vapor ([[Aerosol]]) exhaled by a first generation e-cigarette user.]]
[[File:Cigarrillo electronico funcionando.jpg|thumb|Vapor ([[Aerosol]]) exhaled by a first generation e-cigarette user.]]
First generation e-cigarettes commonly look like tobacco cigarettes and are thus called "cigalikes".<ref name=Farsalinos2014/> They may be designed as a single unit that contains a battery, coil and filling saturated with e-juice in a single tube to be used and disposed of after either the battery is no longer charged or the e-liquid is depleted.<ref name=Farsalinos2014/> They may also be designed as a reusable device with a battery and cartridge called a cartomizer.<ref name=McRobbie2014>Hayden McRobbie, National Centre for Smoking Cessation and Training, 2014. [http://www.ncsct.co.uk/usr/pub/e-cigarette_briefing.pdf Electronic cigarettes]</ref> This is so the battery and cartridge can be separated to allow the battery to be charged when drained or the cartomizer replaced when the e-juice is used up.<ref name=Farsalinos2014/> The battery may contain an electronic airflow sensor whereby activation is triggered simply by drawing breath through the device, while other models employ a power button that must be held during operation.<ref name=McRobbie2014/> An LED in the button or on the end may also be employed to indicate activation.<ref name=EcigGuide2012>{{cite news|title=The skyrocketing popularity of e-cigarettes: A guide|url=http://theweek.com/article/index/232221/the-skyrocketing-popularity-of-e-cigarettes-a-guide|accessdate=21 November 2014|publisher=The Week|date=August 20, 2012}}</ref> Charging is commonly done with a USB charger that the battery attaches to.<ref name=USB-powered>{{cite news |url = http://www.engadget.com/2009/03/31/thankos-usb-powered-health-e-cigarettes-sound-healthy/ |title = Thanko's USB-powered Health E-Cigarettes sound healthy| publisher=Engagdet| author=Tim Stevens |accessdate = 18 November 2014}}</ref> Some manufacturers also have a cigarette pack-shaped portable charging case (PCC), which contains a larger battery capable of recharging e-cigarettes batteries.<ref name=box-charger>{{cite web |url = http://www.engadget.com/2011/07/15/e-lite-electronic-cigarette-review-no-one-ever-said-healthy-was/ |title = E-Lites electronic cigarette review | publisher=Engagdet| author=Terrence O'Brien |accessdate = 18 November 2014}}</ref> Reusable devices can come in a kit that contains a battery, a charger, and at least one cartridge.<ref name=box-charger/> Varying nicotine concentrations are delivered to users because of cartomizer, e-juice mixtures, and battery manufacturing differences.<!-- <ref name=Grana2014/> --> These hardware differences cause differences in the ingredients and their concentrations delivered to users and the surrounding air from the exhaled [[aerosol]], even when the same liquid is used.<ref name=Grana2014/>
First generation e-cigarettes commonly look like tobacco cigarettes and are thus called "cigalikes".<ref name="Farsalinos2014" /> They may be designed as a single unit that contains a battery, coil and filling saturated with e-juice in a single tube to be used and disposed of after either the battery is no longer charged or the e-liquid is depleted.<ref name="Farsalinos2014" /> They may also be designed as a reusable device with a battery and cartridge called a cartomizer.<ref name="McRobbie2014">Hayden McRobbie, National Centre for Smoking Cessation and Training, 2014. [http://www.ncsct.co.uk/usr/pub/e-cigarette_briefing.pdf Electronic cigarettes]</ref> This is so the battery and cartridge can be separated to allow the battery to be charged when drained or the cartomizer replaced when the e-juice is used up.<ref name="Farsalinos2014" /> The battery may contain an electronic airflow sensor whereby activation is triggered simply by drawing breath through the device, while other models employ a power button that must be held during operation.<ref name="McRobbie2014" /> An LED in the button or on the end may also be employed to indicate activation.<ref name="EcigGuide2012">{{cite news|title=The skyrocketing popularity of e-cigarettes: A guide|url=http://theweek.com/article/index/232221/the-skyrocketing-popularity-of-e-cigarettes-a-guide|accessdate=21 November 2014|publisher=The Week|date=August 20, 2012}}</ref> Charging is commonly done with a USB charger that the battery attaches to.<ref name="USB-powered">{{cite news |url = http://www.engadget.com/2009/03/31/thankos-usb-powered-health-e-cigarettes-sound-healthy/ |title = Thanko's USB-powered Health E-Cigarettes sound healthy| publisher=Engagdet| author=Tim Stevens |accessdate = 18 November 2014}}</ref> Some manufacturers also have a cigarette pack-shaped portable charging case (PCC), which contains a larger battery capable of recharging e-cigarettes batteries.<ref name="box-charger">{{cite web |url = http://www.engadget.com/2011/07/15/e-lite-electronic-cigarette-review-no-one-ever-said-healthy-was/ |title = E-Lites electronic cigarette review | publisher=Engagdet| author=Terrence O'Brien |accessdate = 18 November 2014}}</ref> Reusable devices can come in a kit that contains a battery, a charger, and at least one cartridge.<ref name="box-charger" /> Varying nicotine concentrations are delivered to users because of cartomizer, e-juice mixtures, and battery manufacturing differences.<!-- <ref name=Grana2014/> --> These hardware differences cause differences in the ingredients and their concentrations delivered to users and the surrounding air from the exhaled [[aerosol]], even when the same liquid is used.<ref name="Grana2014" />


====Second generation====
====Second generation====
[[File:Lava size 02.jpg|thumb|upright|Second generation PV.]]
[[File:Lava size 02.jpg|thumb|upright|Second generation PV.]]
Second generation devices are often used by more experienced users. These devices are larger overall and look less like tobacco cigarettes.<ref name=McRobbie2014/> They have larger non removable batteries with higher capacity.<ref name=Farsalinos2014/> They are charged with a USB charger that the battery attaches to. Some battery sections have a USB port for recharging and can be used while they are charging or a "passthrough".<ref name=SpinfuelGlossaryP2/> They are usually two part devices meant to be reused and so reduce the cost of operation.<ref name=Farsalinos2014/> Second generation e-cigarettes commonly use a tank or a "clearomizer".<ref name=McRobbie2014/> The tanks are meant to be refilled with bottles of e-juice.<ref name=Farsalinos2014/> They can also be used with cartomizers.<ref name=Farsalinos2014/> Some cheaper batteries use a microphone to activate them.<ref name=HowWork>{{cite web |url = http://www.howtovape.com/page1/page1.html|title = How does the battery work?|accessdate = 3 October 2014}}</ref> Other batteries, like Ego type batteries, can use a custom [[integrated circuit]] to indicate [[Battery (electricity)|battery]] status on the included LED and a button for activation.<ref name=HowWork/> The power button can also used to turn the battery off and on.<ref>{{cite web|title=Joyetech eCom|url=http://www.pcmag.com/article2/0,2817,2430142,00.asp|website=PC|publisher=Ziff Davis|accessdate=24 November 2014}}</ref> These batteries may also have adjustable power adjustments.<ref name=McRobbie2014/>
Second generation devices are often used by more experienced users. These devices are larger overall and look less like tobacco cigarettes.<ref name="McRobbie2014" /> They have larger non removable batteries with higher capacity.<ref name="Farsalinos2014" /> They are charged with a USB charger that the battery attaches to. Some battery sections have a USB port for recharging and can be used while they are charging or a "passthrough".<ref name="SpinfuelGlossaryP2" /> They are usually two part devices meant to be reused and so reduce the cost of operation.<ref name="Farsalinos2014" /> Second generation e-cigarettes commonly use a tank or a "clearomizer".<ref name="McRobbie2014" /> The tanks are meant to be refilled with bottles of e-juice.<ref name="Farsalinos2014" /> They can also be used with cartomizers.<ref name="Farsalinos2014" /> Some cheaper batteries use a microphone to activate them.<ref name="HowWork">{{cite web |url = http://www.howtovape.com/page1/page1.html|title = How does the battery work?|accessdate = 3 October 2014}}</ref> Other batteries, like Ego type batteries, can use a custom [[integrated circuit]] to indicate [[Battery (electricity)|battery]] status on the included LED and a button for activation.<ref name="HowWork" /> The power button can also used to turn the battery off and on.<ref>{{cite web|title=Joyetech eCom|url=http://www.pcmag.com/article2/0,2817,2430142,00.asp|website=PC|publisher=Ziff Davis|accessdate=24 November 2014}}</ref> These batteries may also have adjustable power adjustments.<ref name="McRobbie2014" />


====Third generation====
====Third generation====
[[File:Ecig gen3.jpg|thumb|65px|Third generation PV.]]
[[File:Ecig gen3.jpg|thumb|65px|Third generation PV.]]
Third generation devices includes mechanical mods and variable voltage devices though both are commonly called "mods" are the battery section of the device.<ref name=Farsalinos2014/> Mechanical and variable devices are commonly either cylindrical or a box.<ref name=trading-addictions/> They can be made of wood, aluminium, stainless steel, or brass.<ref name=trading-addictions/> A box can hold larger and sometimes multiple batteries.<ref name=trading-addictions/> Mechanical mods and variable devices use larger batteries.<ref name=vaporizers-explainer/> The battery is installed in the mod and can be removed. This allows the user to change the battery when it is depleted. Variable devices often have a USB connector for recharging and can be used while they are charging as a "passthrough".<ref name=SpinfuelGlossaryP2/><ref name=Vapologist>{{cite news|title=The Vapologist will see you now: Inside New York's first e-cigarette bar|url=http://theweek.com/article/index/251049/the-vapologist-will-see-you-now-inside-new-yorks-first-e-cigarette-bar|accessdate=21 November 2014|publisher=The Week|date=October 11, 2013}}</ref> Mechanical mods do not because they do not contain circuitry. 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.<ref name=MilliAmpHours>{{cite web|title=Understanding MilliAmp Hours|url=http://spinfuel.com/understanding-milliamp-hours/|publisher=Spinfuel Magazine|accessdate=20 November 2014|date=2 January 2014}}</ref> The power section may include additional options, such as displays and support of a wide range of internal batteries and allow different atomizers to be connected.<ref name=McRobbie2014/> Third generation devices commonly use rebuildable atomizers allowing users to chose the wicking material.<ref name=Farsalinos2014/><ref name=McRobbie2014/> Handmade coils can be installed in the atomizer to increase vapor production.<ref name=vaporizers-explainer/> Hardware in this generation is sometimes modified to increase flavor.<ref name=pimpvape>{{cite news|author1=Eric Larson|title=Pimp My Vape: The Rise of E-Cigarette Hackers|url=http://mashable.com/2014/01/25/vaping-subculture/|accessdate=22 November 2014|publisher=Mashable|date=25 January 2014}}</ref> This generation can also use clearomizers.<ref name=Farsalinos2014/> The size of the battery section allows the use of larger tanks that hold more e-liquid.<ref name=trading-addictions/>
Third generation devices includes mechanical mods and variable voltage devices though both are commonly called "mods" are the battery section of the device.<ref name="Farsalinos2014" /> Mechanical and variable devices are commonly either cylindrical or a box.<ref name="trading-addictions" /> They can be made of wood, aluminium, stainless steel, or brass.<ref name="trading-addictions" /> A box can hold larger and sometimes multiple batteries.<ref name="trading-addictions" /> Mechanical mods and variable devices use larger batteries.<ref name="vaporizers-explainer" /> The battery is installed in the mod and can be removed. This allows the user to change the battery when it is depleted. Variable devices often have a USB connector for recharging and can be used while they are charging as a "passthrough".<ref name="SpinfuelGlossaryP2" /><ref name="Vapologist">{{cite news|title=The Vapologist will see you now: Inside New York's first e-cigarette bar|url=http://theweek.com/article/index/251049/the-vapologist-will-see-you-now-inside-new-yorks-first-e-cigarette-bar|accessdate=21 November 2014|publisher=The Week|date=October 11, 2013}}</ref> Mechanical mods do not because they do not contain circuitry. 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.<ref name="MilliAmpHours">{{cite web|title=Understanding MilliAmp Hours|url=http://spinfuel.com/understanding-milliamp-hours/|publisher=Spinfuel Magazine|accessdate=20 November 2014|date=2 January 2014}}</ref> The power section may include additional options, such as displays and support of a wide range of internal batteries and allow different atomizers to be connected.<ref name="McRobbie2014" /> Third generation devices commonly use rebuildable atomizers allowing users to chose the wicking material.<ref name="Farsalinos2014" /><ref name="McRobbie2014" /> Handmade coils can be installed in the atomizer to increase vapor production.<ref name="vaporizers-explainer" /> Hardware in this generation is sometimes modified to increase flavor.<ref name="pimpvape">{{cite news|author1=Eric Larson|title=Pimp My Vape: The Rise of E-Cigarette Hackers|url=http://mashable.com/2014/01/25/vaping-subculture/|accessdate=22 November 2014|publisher=Mashable|date=25 January 2014}}</ref> This generation can also use clearomizers.<ref name="Farsalinos2014" /> The size of the battery section allows the use of larger tanks that hold more e-liquid.<ref name="trading-addictions" />


=== Atomizer ===
=== Atomizer ===
[[File:Dripping Atomizer.jpg|thumb|upright|An e-cigarette atomizer with the coil ([[heating element]]) in view.]]
[[File:Dripping Atomizer.jpg|thumb|upright|An e-cigarette atomizer with the coil ([[heating element]]) in view.]]
An atomizer generally consists of a small [[heating element]] responsible for vaporizing e-liquid, as well as a [[wicking]] material that draws liquid in.<ref name=SpinfuelGlossaryP1>{{cite news |url=http://spinfuel.com/vapers-glossary/ | title=Vaper Talk – The Vaper’s Glossary | work=Spinfuel Magizine | date=5 July 2013 | accessdate=18 November 2014}}</ref> Along with a battery, the atomizer is the central component of every personal vaporizer.
An atomizer generally consists of a small [[heating element]] responsible for vaporizing e-liquid, as well as a [[wicking]] material that draws liquid in.<ref name="SpinfuelGlossaryP1">{{cite news |url=http://spinfuel.com/vapers-glossary/ | title=Vaper Talk – The Vaper’s Glossary | work=Spinfuel Magizine | date=5 July 2013 | accessdate=18 November 2014}}</ref> 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 then connected to the positive and negative poles of the device. When activated the resistance wire (or coil) quickly heats up thus creating a mist from the liquid, which is then inhaled by the user.<ref>{{Cite patent |country=EP |number=2614731|status=application |pubdate=17 July 2013|fdate=12 January 2012|inventor= Yonghai Li, Zhongli Xu |title=An atomizer for electronic cigarette}}</ref>
A small length of [[resistance wire]] is coiled around the wicking material and then connected to the positive and negative poles of the device. When activated the resistance wire (or coil) quickly heats up thus creating a mist from the liquid, which is then inhaled by the user.<ref>{{Cite patent |country=EP |number=2614731|status=application |pubdate=17 July 2013|fdate=12 January 2012|inventor= Yonghai Li, Zhongli Xu |title=An atomizer for electronic cigarette}}</ref>
Line 102: Line 68:
====Cartomizers====
====Cartomizers====
[[File:Carto-45mm.jpg|thumb|A 45mm length, extra-long cartomizer]]
[[File:Carto-45mm.jpg|thumb|A 45mm length, extra-long cartomizer]]
A "cartomizer" (a [[portmanteau word|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.<ref name=SpinfuelGlossaryP1/> They can have up to 3 coils and each coil will increase vapour production.<ref name=SpinfuelGlossaryP1/> It 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.<ref name=SpinfuelGlossaryP1/> Most cartomizers are refillable even if not advertised as such.<ref name=SpinfuelGlossaryP1/><ref>{{cite web|title=E-Cig Basics: What Is a Cartomizer?|url=http://vaperanks.com/e-cig-basics-what-is-a-cartomizer/|publisher=VapeRanks|accessdate=19 November 2013}}</ref>
A "cartomizer" (a [[portmanteau word|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.<ref name="SpinfuelGlossaryP1" /> They can have up to 3 coils and each coil will increase vapour production.<ref name="SpinfuelGlossaryP1" /> It 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.<ref name="SpinfuelGlossaryP1" /> Most cartomizers are refillable even if not advertised as such.<ref name="SpinfuelGlossaryP1" /><ref>{{cite web|title=E-Cig Basics: What Is a Cartomizer?|url=http://vaperanks.com/e-cig-basics-what-is-a-cartomizer/|publisher=VapeRanks|accessdate=19 November 2013}}</ref>


Cartomizers can be used on their own or in conjunction with a tank that allows more e-liquid capacity.<ref name=SpinfuelGlossaryP1/> 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.<ref name=SpinfuelGlossaryP1/>
Cartomizers can be used on their own or in conjunction with a tank that allows more e-liquid capacity.<ref name="SpinfuelGlossaryP1" /> 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.<ref name="SpinfuelGlossaryP1" />


====Clearomizers====
====Clearomizers====
[[File:E-cigarette.jpg|upright|thumb|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.]]
[[File:E-cigarette.jpg|upright|thumb|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.<ref>{{cite news | url=http://www.thetelegraph.com/news/community-home_top-news/717182/Smoking-going-electronic | title=Smoking going electronic | work=Thetelegraph.com | date=29 January 2014 | accessdate=6 February 2014 | author=Greg Olson}}</ref> Unlike cartotanks, however, no poly-foam material can be found in them. There are a lot of different wicking systems employed inside of clearomizers to ensure good moistening of the wick without flooding the coil. Some rely on [[gravitation|gravity]] to bring the e-liquid to the wick and coil assembly (bottom coil clearomizers for example) whereas others rely on capillary action and to some degree the user agitating the e-liquid while handling the clearomizer (top coil clearomizers).<ref name=SpinfuelGlossaryP1 /><ref>{{cite web | url=http://www.dxtechinc.com/whats-the-choice-between-a-clearomizer-vs-atomizer/ | title=WHAT'S THE CHOICE BETWEEN A CLEAROMIZER VS ATOMIZER? | accessdate=6 February 2014}}</ref> The coil and wicks are typically inside a prefabricated assembly or "head" that is replaceable by the user and can contain either single or dual coils.
Clearomizers or "clearos", not unlike cartotanks, use a clear tank in which an atomizer is inserted.<ref>{{cite news | url=http://www.thetelegraph.com/news/community-home_top-news/717182/Smoking-going-electronic | title=Smoking going electronic | work=Thetelegraph.com | date=29 January 2014 | accessdate=6 February 2014 | author=Greg Olson}}</ref> Unlike cartotanks, however, no poly-foam material can be found in them. There are a lot of different wicking systems employed inside of clearomizers to ensure good moistening of the wick without flooding the coil. Some rely on [[gravitation|gravity]] to bring the e-liquid to the wick and coil assembly (bottom coil clearomizers for example) whereas others rely on capillary action and to some degree the user agitating the e-liquid while handling the clearomizer (top coil clearomizers).<ref name="SpinfuelGlossaryP1" /><ref>{{cite web | url=http://www.dxtechinc.com/whats-the-choice-between-a-clearomizer-vs-atomizer/ | title=WHAT'S THE CHOICE BETWEEN A CLEAROMIZER VS ATOMIZER? | accessdate=6 February 2014}}</ref> The coil and wicks are typically inside a prefabricated assembly or "head" that is replaceable by the user and can contain either single or dual coils.
Present day clearomizers commonly have adjustable air flow control. They also hold up to 5ml of e-liquid. Tanks can be either plastic or glass. Some flavours of e-juice have been known to crack plastic clearomizer tanks.<ref name=crackedtank>{{cite web | url=http://ecigarettereviewed.com/e-liquid-and-tank-safety | title=ecigarettereviewed.com | accessdate=6 November 2014}}</ref>
Present day clearomizers commonly have adjustable air flow control. They also hold up to 5ml of e-liquid. Tanks can be either plastic or glass. Some flavours of e-juice have been known to crack plastic clearomizer tanks.<ref name="crackedtank">{{cite web | url=http://ecigarettereviewed.com/e-liquid-and-tank-safety | title=ecigarettereviewed.com | accessdate=6 November 2014}}</ref>


====Rebuildable atomizers====
====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 by an [[wikt:off-the-shelf|off-the-shelf]] atomizer "head".<ref name=Farsalinos2014/> They are generally considered advanced devices. They also allow the user to build atomizers at any desired electrical resistance.<ref name=Farsalinos2014/> The materials needed to "rebuild" the atomizers are usually much cheaper than the usual prefabricated replaceable wick and coil assemblies used in clearomizers.
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 by an [[wikt:off-the-shelf|off-the-shelf]] atomizer "head".<ref name="Farsalinos2014" /> They are generally considered advanced devices. They also allow the user to build atomizers at any desired electrical resistance.<ref name="Farsalinos2014" /> The materials needed to "rebuild" the atomizers are usually much cheaper than the usual prefabricated replaceable wick and coil assemblies used in clearomizers.


These atomizers are divided into three main categories; rebuildable tank atomizers (RTAs), rebuildable dripping atomizers (RDAs),<ref name=3StepsRebuild>{{cite web|title=3 steps to rebuilding atomizers|url=http://vapenewsmagazine.com/november-2013/3-steps-to-rebuilding-atomizers|website=Vapenews Magazine|publisher=Vapenews Magazine|accessdate=21 November 2014}}</ref> and rebuildable dripping tank atomizers (RDTAs).
These atomizers are divided into three main categories; rebuildable tank atomizers (RTAs), rebuildable dripping atomizers (RDAs),<ref name="3StepsRebuild">{{cite web|title=3 steps to rebuilding atomizers|url=http://vapenewsmagazine.com/november-2013/3-steps-to-rebuilding-atomizers|website=Vapenews Magazine|publisher=Vapenews Magazine|accessdate=21 November 2014}}</ref> and rebuildable dripping tank atomizers (RDTAs).


Rebuildable tank atomizers (RTAs) are similar to clearomizers in that they use a tank or container to hold and bring liquid to the coil. They usually hold significantly more e-liquid than other atomizers or clearomizers. The tank can be either plastic, glass, or metal. 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. The drawbacks of Genesis style atomizers include leaking if they are not not kept upright.
Rebuildable tank atomizers (RTAs) are similar to clearomizers in that they use a tank or container to hold and bring liquid to the coil. They usually hold significantly more e-liquid than other atomizers or clearomizers. The tank can be either plastic, glass, or metal. 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. The drawbacks of Genesis style atomizers include leaking if they are not not kept upright.


Rebuildable dripping atomizers (RDAs) are atomizers where the ejuice 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.<ref name=pimpvape/> A "top cap" to cover the coils with airflow holes and a hole at the top where a mouth piece can be attached. The wick is generally larger than 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 help dissipate the heat from the coil before it reaches the mouth piece or "drip tip".
Rebuildable dripping atomizers (RDAs) are atomizers where the ejuice 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.<ref name="pimpvape" /> A "top cap" to cover the coils with airflow holes and a hole at the top where a mouth piece can be attached. The wick is generally larger than 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 help 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.
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.
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==== Variable power and voltage devices ====
==== Variable power and voltage devices ====
[[File:Innokin SVD.jpg|thumb|upright|PV with variable and regulated power offering battery protection]]
[[File:Innokin SVD.jpg|thumb|upright|PV with variable and regulated power offering battery protection]]
Variable [[wattage|power]] and or voltage are personal vaporizer devices that contain a built-in [[electronic chip]] allowing the user to adjust the power that goes through the heating element.<ref name=McRobbie2014/> They are often rectangular in shape but can also be cylindrical.<ref name=trading-addictions/> They usually incorporate an LED screen to display information.<ref>{{cite news | url=http://online.wsj.com/article/PR-CO-20140129-910446.html | title=Vapor Corp. Launches New Store-in-Store VaporX(R) Retail Concept at Tobacco Plus Convenience Expo in Las Vegas | work=The Wall Street Journal | date=29 January 2014 | accessdate=6 February 2014}}</ref> Variable wattage lets you adjust the voltage to the coil. Variable wattage devices check the ohms of the coil and automatically adjust the voltage to get the desired power to the coil.<ref>{{cite news | url=http://spinfuel.com/taking-the-mystery-out-of-variable-wattage/ | title=Taking The Mystery Out Of Variable Wattage | work=Spinfuel Magizine | date=28 February 2013 | accessdate=18 November 2014}}</ref> Vairable devices are either variable wattage, variable voltage or both.<ref name=SpinfuelGlossaryP2>{{cite news |url=http://spinfuel.com/vapers-glossary/2/ | title=Vaper Talk – The Vaper’s Glossary page 2 | work=Spinfuel Magizine | date=5 July 2013 | accessdate=18 November 2014}}</ref> To adjust the settings the user presses buttons or rotates a dial to make adjustments in power either up or down.<ref name=digitaltrends.com/> The amount of power has a direct relationship to the heat produced by the coil, thus changing the vapor output.<ref name=McRobbie2014/><ref name=digitaltrends.com/> Greater heat generated by the coil increases vapor production.<ref name=digitaltrends.com/> Some of these devices include additional settings through their menu system such as: atomizer resistance checker, remaining battery voltage, puff counter, activation cut-off etc.<ref>{{cite web|url=http://realelectriccigarettereviews.com/joyetech-evic-review/ | title=JoyeTech eVic Review | publisher=Real Electric Cigarettes Reviews}}</ref>
Variable [[wattage|power]] and or voltage are personal vaporizer devices that contain a built-in [[electronic chip]] allowing the user to adjust the power that goes through the heating element.<ref name="McRobbie2014" /> They are often rectangular in shape but can also be cylindrical.<ref name="trading-addictions" /> They usually incorporate an LED screen to display information.<ref>{{cite news | url=http://online.wsj.com/article/PR-CO-20140129-910446.html | title=Vapor Corp. Launches New Store-in-Store VaporX(R) Retail Concept at Tobacco Plus Convenience Expo in Las Vegas | work=The Wall Street Journal | date=29 January 2014 | accessdate=6 February 2014}}</ref> Variable wattage lets you adjust the voltage to the coil. Variable wattage devices check the ohms of the coil and automatically adjust the voltage to get the desired power to the coil.<ref>{{cite news | url=http://spinfuel.com/taking-the-mystery-out-of-variable-wattage/ | title=Taking The Mystery Out Of Variable Wattage | work=Spinfuel Magizine | date=28 February 2013 | accessdate=18 November 2014}}</ref> Vairable devices are either variable wattage, variable voltage or both.<ref name="SpinfuelGlossaryP2">{{cite news |url=http://spinfuel.com/vapers-glossary/2/ | title=Vaper Talk – The Vaper’s Glossary page 2 | work=Spinfuel Magizine | date=5 July 2013 | accessdate=18 November 2014}}</ref> To adjust the settings the user presses buttons or rotates a dial to make adjustments in power either up or down.<ref name="digitaltrends.com" /> The amount of power has a direct relationship to the heat produced by the coil, thus changing the vapor output.<ref name="McRobbie2014" /><ref name="digitaltrends.com" /> Greater heat generated by the coil increases vapor production.<ref name="digitaltrends.com" /> Some of these devices include additional settings through their menu system such as: atomizer resistance checker, remaining battery voltage, puff counter, activation cut-off etc.<ref>{{cite web|url=http://realelectriccigarettereviews.com/joyetech-evic-review/ | title=JoyeTech eVic Review | publisher=Real Electric Cigarettes Reviews}}</ref>


==== Mechanical personal vaporizers ====
==== Mechanical personal vaporizers ====
[[File:King Mod And Kaifun Lite.jpg|upright|thumb|Mechanical PV with a rebuildable atomizer]]
[[File:King Mod And Kaifun Lite.jpg|upright|thumb|Mechanical PV with a rebuildable atomizer]]
Mechanical PVs or mechanical "mods", often called "mechs", are devices without electronic components and battery protection (apart from vent holes drilled in some mechanical devices) or voltage regulation. Because there is neither protection nor regulation, they will work either way the battery is inserted. They are activated by spring loaded or opposing [[magnetic]] mechanical [[switches]], hence their name. They rely on the natural voltage output of a battery and the material that the mod is made of.<ref name=Amann2014>{{cite web | url=http://onvaping.com/battery-safety-and-ohms-law/ | title=Battery Safety and Ohm’s Law | publisher=onvaping.com | author=Dale Amann | date=10 February 2014 | accessdate=1 October 2014}}</ref>
Mechanical PVs or mechanical "mods", often called "mechs", are devices without electronic components and battery protection (apart from vent holes drilled in some mechanical devices) or voltage regulation. Because there is neither protection nor regulation, they will work either way the battery is inserted. They are activated by spring loaded or opposing [[magnetic]] mechanical [[switches]], hence their name. They rely on the natural voltage output of a battery and the material that the mod is made of.<ref name="Amann2014">{{cite web | url=http://onvaping.com/battery-safety-and-ohms-law/ | title=Battery Safety and Ohm’s Law | publisher=onvaping.com | author=Dale Amann | date=10 February 2014 | accessdate=1 October 2014}}</ref>


The term "mod" was originally used instead of "modification".<ref name=Farsalinos2014/> Users would modify existing hardware to get better performance, and as an alternative to the e-cigarettes that looked like traditional cigarettes.<ref name=digitaltrends.com/> Users would also modify other items like flashlights as battery compartments to power atomizers.<ref name="trading-addictions"/><ref name=digitaltrends.com/> Today the word mod is used to describe most personal vaporizers either bought in a store or created by the user.
The term "mod" was originally used instead of "modification".<ref name="Farsalinos2014" /> Users would modify existing hardware to get better performance, and as an alternative to the e-cigarettes that looked like traditional cigarettes.<ref name="digitaltrends.com" /> Users would also modify other items like flashlights as battery compartments to power atomizers.<ref name="trading-addictions" /><ref name="digitaltrends.com" /> Today the word mod is used to describe most personal vaporizers either bought in a store or created by the user.


They are commonly used with "low resistance" (1.0Ω ~ 0.2Ω) rebuildable atomizers.<ref name=SpinfuelFirstMod>{{cite web | url=http://spinfuel.com/first-mechanical-mod/ | title=Time For Your First Mechanical Mod? | publisher=Spinfuel Magizine | author=Team Spinfuel | date=11 January 2014 | accessdate=18 November 2014}}</ref> Seeing that most e-cigarettes containing electronic battery protection will interpret sub ohm resistance coils as a [[short circuit]], thus prohibiting the device from being activated, mechanical mods are among the only devices that will accept such atomizer resistances although more recent (2013) electronic devices have this possibility as well.{{citation needed|date=November 2013}}
They are commonly used with "low resistance" (1.0Ω ~ 0.2Ω) rebuildable atomizers.<ref name="SpinfuelFirstMod">{{cite web | url=http://spinfuel.com/first-mechanical-mod/ | title=Time For Your First Mechanical Mod? | publisher=Spinfuel Magizine | author=Team Spinfuel | date=11 January 2014 | accessdate=18 November 2014}}</ref> Seeing that most e-cigarettes containing electronic battery protection will interpret sub ohm resistance coils as a [[short circuit]], thus prohibiting the device from being activated, mechanical mods are among the only devices that will accept such atomizer resistances although more recent (2013) electronic devices have this possibility as well.{{citation needed|date=November 2013}}


Since mechanical PVs have no power regulation and are unprotected, they require special attention on the user's part that other regulated and protected PVs do not need. Making sure that the battery does not over-discharge and that the atomizer will not require more [[amperage]] than what the battery can safely allow are the user's responsibilities.<ref name=Amann2014/>
Since mechanical PVs have no power regulation and are unprotected, they require special attention on the user's part that other regulated and protected PVs do not need. Making sure that the battery does not over-discharge and that the atomizer will not require more [[amperage]] than what the battery can safely allow are the user's responsibilities.<ref name="Amann2014" />


===E-liquid===
===E-liquid===
E-liquid, e-juice or simply "juice", refers to a liquid solution that when heated by an atomizer produces mist. The main ingredients of e-liquids are usually a mix of propylene glycol (PG), [[glycerin]] (G), and/or [[PEG 400|polyethylene glycol 400]] (PEG400), sometimes with differing levels of alcohol mixed with concentrated or extracted flavourings; and optionally, a variable concentration of tobacco-derived nicotine.<ref name=Caponnetto2013/><ref name=Sales2012>{{cite web|url=http://usatoday30.usatoday.com/news/health/story/2012-08-18/electronic-cigarettes-smokeless-vaping-risks/57121894/1|publisher=[[USA Today]]|title=E-cigarettes: No smoke, but fiery debate over safety|accessdate=20 July 2013}}</ref> The nicotine may be obtained from tobacco plants or tobacco dust.<ref name=Chang2014>{{cite journal|last1=Chang|first1=H.|title=Research gaps related to the environmental impacts of electronic cigarettes|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii54–ii58|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051480|pmc=3995274|pmid=24732165}}</ref> Most e-cigarette liquids contain nicotine, but the level of nicotine is chosen by the consumer.<ref name=Bur2014/> E-liquid that does not contain nicotine is also available.<ref name=Bur2014/>
E-liquid, e-juice or simply "juice", refers to a liquid solution that when heated by an atomizer produces mist. The main ingredients of e-liquids are usually a mix of propylene glycol (PG), [[glycerin]] (G), and/or [[PEG 400|polyethylene glycol 400]] (PEG400), sometimes with differing levels of alcohol mixed with concentrated or extracted flavourings; and optionally, a variable concentration of tobacco-derived nicotine.<ref name="Caponnetto2013" /><ref name="Sales2012">{{cite web|url=http://usatoday30.usatoday.com/news/health/story/2012-08-18/electronic-cigarettes-smokeless-vaping-risks/57121894/1|publisher=[[USA Today]]|title=E-cigarettes: No smoke, but fiery debate over safety|accessdate=20 July 2013}}</ref> The nicotine may be obtained from tobacco plants or tobacco dust.<ref name="Chang2014">{{cite journal|last1=Chang|first1=H.|title=Research gaps related to the environmental impacts of electronic cigarettes|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii54–ii58|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051480|pmc=3995274|pmid=24732165}}</ref> Most e-cigarette liquids contain nicotine, but the level of nicotine is chosen by the consumer.<ref name="Bur2014" /> E-liquid that does not contain nicotine is also available.<ref name="Bur2014" />


The solution is often sold in bottles or pre-filled disposable cartridges, or as a kit for consumers to make their own eJuices. Components are also available to modify or boost their flavour, nicotine strength, or concentration of e-liquid.<ref name=DiyLiquid>{{cite web|url=http://www.ecigarettemag.com/e-liquid-mixing/|publisher=ecigarettemag.com|title=E-liquid Mixing Guide – a Guide to DIY Mixing|accessdate=10 November 2014}}</ref> Pre-made e-liquids are manufactured with various tobacco, fruit, and other flavors,<ref name=Grana2014/> as well as variable nicotine concentrations (including nicotine-free versions). The standard notation "mg/ml" is often used in labelling for denoting nicotine concentration, and is sometimes shortened to a simple "mg".<ref name=Laugesen2007>{{cite web|url=http://www.healthnz.co.nz/Ruyan_ecigarette.htm |author=Murray Laugesen|title=The Ruyan e-cigarette; Technical Information Sheet|publisher=Health New Zealand|date=17 October 2007|accessdate=31 March 2008}}</ref> In surveys of regular e-cigarette users the most liked e-liquids had a nicotine content of 18&nbsp;mg/ml, and largely the favorite flavors were tobacco, mint and fruit.<ref name=Hajek2014/> A cartridge may contain 0 to 20 mg of nicotine.<ref name=Cervellin2013/> A refill bottle can contain up to 1 g of nicotine.<ref name=Cervellin2013>{{cite journal|last1=Cervellin|first1=Gianfranco|last2=Borghi|first2=Loris|last3=Mattiuzzi|first3=Camilla|last4=Meschi|first4=Tiziana|last5=Favaloro|first5=Emmanuel|last6=Lippi|first6=Giuseppe|title=E-Cigarettes and Cardiovascular Risk: Beyond Science and Mysticism|journal=Seminars in Thrombosis and Hemostasis|volume=40|issue=01|year=2013|pages=060–065|issn=0094-6176|doi=10.1055/s-0033-1363468|pmid=24343348}}</ref> The flavorings may be natural or artificial.<ref name=Bertholon2013/>
The solution is often sold in bottles or pre-filled disposable cartridges, or as a kit for consumers to make their own eJuices. Components are also available to modify or boost their flavour, nicotine strength, or concentration of e-liquid.<ref name="DiyLiquid">{{cite web|url=http://www.ecigarettemag.com/e-liquid-mixing/|publisher=ecigarettemag.com|title=E-liquid Mixing Guide – a Guide to DIY Mixing|accessdate=10 November 2014}}</ref> Pre-made e-liquids are manufactured with various tobacco, fruit, and other flavors,<ref name="Grana2014" /> as well as variable nicotine concentrations (including nicotine-free versions). The standard notation "mg/ml" is often used in labelling for denoting nicotine concentration, and is sometimes shortened to a simple "mg".<ref name="Laugesen2007">{{cite web|url=http://www.healthnz.co.nz/Ruyan_ecigarette.htm |author=Murray Laugesen|title=The Ruyan e-cigarette; Technical Information Sheet|publisher=Health New Zealand|date=17 October 2007|accessdate=31 March 2008}}</ref> In surveys of regular e-cigarette users the most liked e-liquids had a nicotine content of 18&nbsp;mg/ml, and largely the favorite flavors were tobacco, mint and fruit.<ref name="Hajek2014" /> A cartridge may contain 0 to 20 mg of nicotine.<ref name="Cervellin2013" /> A refill bottle can contain up to 1 g of nicotine.<ref name="Cervellin2013">{{cite journal|last1=Cervellin|first1=Gianfranco|last2=Borghi|first2=Loris|last3=Mattiuzzi|first3=Camilla|last4=Meschi|first4=Tiziana|last5=Favaloro|first5=Emmanuel|last6=Lippi|first6=Giuseppe|title=E-Cigarettes and Cardiovascular Risk: Beyond Science and Mysticism|journal=Seminars in Thrombosis and Hemostasis|volume=40|issue=01|year=2013|pages=060–065|issn=0094-6176|doi=10.1055/s-0033-1363468|pmid=24343348}}</ref> The flavorings may be natural or artificial.<ref name="Bertholon2013">{{cite journal|last1=Bertholon|first1=J.F.|last2=Becquemin|first2=M.H.|last3=Annesi-Maesano|first3=I.|last4=Dautzenberg|first4=B.|title=Electronic Cigarettes: A Short Review|journal=Respiration|year=2013|issn=1423-0356|doi=10.1159/000353253|pmid=24080743}}</ref>

==Health effects==
===Position of medical organizations===
{{Main|Positions of medical organizations regarding electronic cigarettes}}
{{Asof|2014}} electronic cigarettes have not been approved for helping people quit smoking by any government.<ref name="WHOPosition20142" /> In July 2014, a report produced by the [[World Health Organization]] (WHO) for the Conference of the Parties to the [[WHO Framework Convention on Tobacco Control]], found there was not enough evidence to determine if electronic cigarettes can help people quit smoking.<!-- <ref name=WHOPosition2014/> --> It suggested that smokers should be encouraged to use approved methods for help with quitting.<ref name="WHOPosition20142" />
<nowiki> </nowiki>But the same report also mentioned expert opinions in scientific papers
<nowiki> </nowiki>that suggested e-cigarettes may have a role helping people quit who
have failed using other methods.<ref name="WHOPosition20142">{{cite web|last1=WHO|title=Electronic nicotine delivery systems|url=http://apps.who.int/gb/fctc/PDF/cop6/FCTC_COP6_10-en.pdf|accessdate=28 August 2014}}</ref>
<nowiki> </nowiki>A previous WHO statement from July 2013 stated that e-cigarettes have
not been shown to be effective helping people quit smoking.<ref name="WHOJuly20132">{{cite web|title=Tobacco Free Initiative (TFI)|url=https://web.archive.org/web/20130721131331/http://www.who.int/tobacco/communications/statements/eletronic_cigarettes/en|website=World Health Organization|date=9 July 2013}}</ref>
<nowiki> </nowiki>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.<ref name="WHOJuly20132" /> The [[World Lung Foundation]]
<nowiki> </nowiki>applauded the 2014 WHO report's recommendation for tighter regulation
of e-cigarettes due to concerns about the safety of e-cigarettes and the
<nowiki> </nowiki>possible increased nicotine or tobacco addiction among youth.<ref>{{cite web|title=WHO Right to Call for E-Cigarette Regulation|url=http://www.worldlungfoundation.org/ht/d/ReleaseDetails/i/32757|publisher=World Lung Federation|accessdate=6 November 2014}}</ref>

The UK [[National Health Service]]
<nowiki> </nowiki>has concluded, "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."<ref>{{cite web|title=Stop smoking treatments|url=http://www.nhs.uk/Conditions/Smoking-%28quitting%29/Pages/Treatment.aspx|publisher=UK National Health Service|accessdate=6 November 2014}}</ref>

In 2014, the US [[Food and Drug Administration]]
<nowiki> </nowiki>(FDA) concluded, "E-cigarettes have not been fully studied, so
consumers currently don’t know: the potential risks of e-cigarettes when
<nowiki> </nowiki>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."<ref>{{cite web|title=Electronic Cigarettes (e-Cigarettes)|url=http://www.fda.gov/NewsEvents/PublicHealthFocus/ucm172906.htm|publisher=US Food and Drug Administration|accessdate=6 November 2014}}</ref>

===Smoking cessation===

{{Asof|2014}}, research on the safety and efficacy of e-cigarette use for [[smoking cessation]] is limited.<ref name="Franck20142">{{cite journal|last1=Franck|first1=C.|last2=Budlovsky|first2=T.|last3=Windle|first3=S. B.|last4=Filion|first4=K. B.|last5=Eisenberg|first5=M. J.|title=Electronic Cigarettes in North America: History, Use, and Implications for Smoking Cessation|journal=Circulation|volume=129|issue=19|year=2014|pages=1945–1952|issn=0009-7322|doi=10.1161/CIRCULATIONAHA.113.006416|pmid=24821825}}</ref> Their benefit in helping people quit smoking is uncertain.<ref name="Harrell20142">{{cite journal |last1=Harrell |first1=PT|last2=Simmons|first2=VN|last3=Correa|first3=JB|last4=Padhya|first4=TA|last5=Brandon|first5=TH|title=Electronic Nicotine Delivery Systems ("E-cigarettes"): Review of Safety and Smoking Cessation Efficacy.|journal=Otolaryngology—head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery|date= 4 June 2014|pmid=24898072|quote=These devices are unregulated, of unknown safety, and of uncertain benefit in quitting smoking.|doi=10.1177/0194599814536847}}</ref> A 2014 [[Cochrane review]] found that e-cigarettes can help people quit, but was based on a small number of studies.<ref name="Cochrane20142">{{cite journal|last1=McRobbie|first1=Hayden|last2=Bullen|first2=Chris|last3=Hartmann-Boyce|first3=Jamie|last4=Hajek|first4=Peter|last5=McRobbie|first5=Hayden|title=Electronic cigarettes for smoking cessation and reduction|journal=The Cochrane Library|year=2014|doi=10.1002/14651858.CD010216.pub2|pmid=25515689}}</ref>

Two 2014 reviews
found no evidence that e-cigarettes are more effective than existing
nicotine replacement treatments for smoking cessation.<ref name="Drummond20142" /><ref name="Cochrane20142" /> One of these reviews stated that to encourage e-cigarette use as a cessation aid in cigarette users is premature.<ref name="Drummond20142" /> A 2013 [[randomized controlled trial]]
<nowiki> </nowiki>found higher smoking cessation rates associated with e-cigarettes with
nicotine than e-cigarettes without nicotine or traditional NRT patches,
but the study was too small to make these results statistically
significant.<ref name="Polosa20132">{{citation|first=Riccardo |last=Polosa|first2=Brad|last2=Rodu|author3-first=Pasquale|author3-last=Caponnetto|author4-first=Marilena |author4-last=Maglia|author5-first=Cirino |author5-last=Raciti|journal=Harm Reduction Journal| volume=10|issue=10|title=A fresh look at tobacco harm reduction: the case for the electronic cigarette |year=2013|url=http://www.biomedcentral.com/content/pdf/1477-7517-10-19.pdf|pmid=24090432|doi=10.1186/1477-7517-10-19}}</ref> There are some [[non-controlled studies]] which have reported possible benefit.<ref name="Caponnetto20132">{{cite journal|title=Electronic cigarette: a possible substitute for cigarette dependence.|journal=Monaldi archives for chest disease|date=Mar 2013|author1=Caponnetto P|author2=Russo C|author3=Bruno CM|author4=Alamo A|author5=Amaradio MD|author6=Polosa R.|volume=79|issue=1|pages=12–19|pmid=23741941}}</ref> Electronic cigarettes were not regularly associated with trying to quit tobacco among young people.<ref name="Car20142">{{cite journal|last=Carroll Chapman|first=SL|author2=Wu, LT|title=E-cigarette prevalence and correlates of use among adolescents versus adults: A review and comparison.|journal=Journal of Psychiatric Research|date=18 Mar 2014|pmid=24680203|doi=10.1016/j.jpsychires.2014.03.005|volume=54|pages=43–54}}</ref>
<nowiki> </nowiki>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.<ref name="Pisinger20142" /> This review therefore called for their use to be limited to smokers who are unwilling or unable to quit.<ref name="Pisinger20142">{{cite journal|last1=Pisinger|first1=Charlotta|last2=Døssing|first2=Martin|title=A systematic review of health effects of electronic cigarettes|journal=Preventive Medicine|date=December 2014|volume=69|pages=248–260|doi=10.1016/j.ypmed.2014.10.009}}</ref>
<nowiki> </nowiki>A 2014 review found four experimental studies and six cohort studies
that indicated that electronic cigarettes reduced the desire to smoke
and withdrawal symptoms.<ref name="Gualano20142" />
<nowiki> </nowiki>This review also noted that two cohort studies found that electronic
cigarettes led to a reduction in the number of cigarettes smoked per
day.<ref name="Gualano20142">{{cite journal|last1=Gualano|first1=M. R.|last2=Passi|first2=S.|last3=Bert|first3=F.|last4=La Torre|first4=G.|last5=Scaioli|first5=G.|last6=Siliquini|first6=R.|title=Electronic cigarettes: assessing the efficacy and the adverse effects through a systematic review of published studies|journal=Journal of Public Health|date=9 August 2014|doi=10.1093/pubmed/fdu055|pmid=25108741}}</ref>

=== Harm reduction ===
[[Tobacco harm reduction]] has been a controversial area of tobacco control.<ref name="Cahn20112">{{cite journal |last1= M. |first1=Z. |last2=Siegel |title=Electronic cigarettes as a harm reduction strategy for tobacco control: a step forward or a repeat of past mistakes? |journal=Journal of public health policy |date=February 2011 |volume=32 |issue=1 |pages=16–31 |pmid=21150942 |doi= 10.1057/jphp.2010.41 |first2= M}}</ref> The health community have been cautious to support the [[tobacco industry]] to bring safer products to market that will lessen the risks related with tobacco use.<ref name="Cahn20112" /> A 2011 review found in the fight to decrease tobacco related death and disease, e-cigarettes show great promise.<ref name="Cahn20112" />
<nowiki> </nowiki>A 2014 review found no long-term evidence on the safety or efficacy of
e-cigarettes, including whether they reduce harm for tobacco related
disease or will improve the health of the population as a whole.<!-- <ref name=Drummond2014/> --> Therefore, promotion of e-cigarettes as a harm reduction product is premature.<ref name="Drummond20142">{{cite journal|last1=Drummond|first1=MB|last2=Upson|first2=D|title=Electronic cigarettes. Potential harms and benefits.|journal=Annals of the American Thoracic Society|date=February 2014|volume=11|issue=2|pages=236–42|pmid=24575993|doi=10.1513/annalsats.201311-391fr}}</ref> A 2014 review found e-cigarettes may be less harmful than tobacco cigarettes to users and bystanders.<ref name="Hajek20142" />
<nowiki> </nowiki>The same review concluded that health professionals may consider
advising smokers who are reluctant to quit by way of other methods to
switch to e-cigarettes as a safer alternative to smoking.<ref name="Hajek20142" />
<nowiki> </nowiki>A 2014 review argued that regulations for electronic cigarettes should
be similar to those for dietary supplements or cosmetic products to not
limit the potential for harm reduction with electronic cigarettes
replacing tobacco.<ref name="Saitta20142">{{cite journal|last=Saitta|first=D|author2=Ferro, GA |author3=Polosa, R |title=Achieving appropriate regulations for electronic cigarettes.|journal=Therapeutic advances in chronic disease|date=Mar 2014|volume=5|issue=2|pages=50–61|pmid=24587890|doi=10.1177/2040622314521271|pmc=3926346}}</ref>
<nowiki> </nowiki>A 2012 review found electronic systems appear to generally deliver less
<nowiki> </nowiki>nicotine than smoking, raising the question of whether they can
effectively substitute for tobacco smoking over a long-term period.<ref name="O20122" />
<nowiki> </nowiki>A 2012 review found e-cigarettes could considerably reduce traditional
cigarettes use and they likely could be used as a lower risk replacement
<nowiki> </nowiki>for traditional cigarettes, but there is not enough data on the safety
and efficacy to draw definite conclusions.<ref name="Caponnetto20122">{{cite journal|last1=Caponnetto|first1=Pasquale|last2=Campagna|first2=Davide|last3=Papale|first3=Gabriella|last4=Russo|first4=Cristina|last5=Polosa|first5=Riccardo|title=The emerging phenomenon of electronic cigarettes|journal=Expert Review of Respiratory Medicine|volume=6|issue=1|year=2012|pages=63–74|issn=1747-6348|doi=10.1586/ers.11.92|pmid=22283580}}</ref>

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 mist of e-cigarettes.<ref name="Cahn20112" />
<nowiki> </nowiki>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.<ref name="Cahn20112" />
<nowiki> </nowiki>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.<ref name="FarsalinosPolosa20142">{{cite journal|last1=Farsalinos|first1=K. E.|last2=Polosa|first2=R.|title=Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes: a systematic review|journal=Therapeutic Advances in Drug Safety|volume=5|issue=2|year=2014|pages=67–86|issn=2042-0986|doi=10.1177/2042098614524430|pmc=4110871|pmid=25083263}}</ref> Adults most frequently use electronic cigarettes as a replacement for tobacco, but not always to quit.<ref name="Car20142" />
<nowiki> </nowiki>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.<ref name="Grana20142">{{cite journal|last=Grana|first=R|author2=Benowitz, N |author3=Glantz, SA |title=E-cigarettes: a scientific review.|journal=Circulation|date=13 May 2014|volume=129|issue=19|pages=1972–86|pmid=24821826|doi=10.1161/circulationaha.114.007667|pmc=4018182}}</ref> Some users want to reduce harm from smoking.<ref name="NHE20142" />

In 2014 a report commissioned by [[Public Health England]]
<nowiki> </nowiki>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.<ref name="NHE20142">{{cite web|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/311887/Ecigarettes_report.pdf|title=Electronic cigarettes – A report commissioned by Public Health England |publisher=[[Public Health England]]|date=15 May 2014|author1-first=John |author1-last=Britton|author2-first=Ilze|author2-last=Bogdanovica}}</ref>
<nowiki> </nowiki>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.<ref name="BMAhandout20132">{{cite web|title=BMA calls for stronger regulation of e-cigarettes|url=http://bma.org.uk/-/media/Files/PDFs/Working%20for%20change/Improving%20health/tobaccoecigarettespublicplaces_jan2013.pdf|publisher=British Medical Association|accessdate=18 November 2013}}</ref> The [[American Association of Public Health Physicians]]
<nowiki> </nowiki>(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.<ref>{{cite web |title=Principles to Guide AAPHP Tobacco Policy |url=http://www.aaphp.org/tobacco|work=American Association of Public Health Physicians |accessdate=31 July 2013}}</ref> In an interview, the director of the Office on Smoking and Health for the U.S. federal agency [[Centers for Disease Control and Prevention]]
<nowiki> </nowiki>(CDC) believes that there is enough evidence to say that using
e-cigarettes is likely less harmful than smoking a pack of conventional
cigarettes.<!-- <ref name=CDCQ&A/> -->
<nowiki> </nowiki>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.<ref name="CDCQ&A2">{{cite web |author=Edgar, Julie |title=E-Cigarettes: Expert Q&A With the CDC |url=http://www.webmd.com/smoking-cessation/news/20131112/e-cigarettes-cdc |publisher=WebMD |accessdate=17 November 2013}}</ref>
<nowiki> </nowiki>A 2014 WHO report concluded that some smokers will switch completely to
<nowiki> </nowiki>e-cigarettes from traditional tobacco but a "sizeable" number will use
both tobacco cigarettes and electronic cigarettes.<!-- <ref name=WHOPosition2014/> -->
<nowiki> </nowiki>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."<ref name="WHOPosition20142" />

=== Safety ===
{{Main|Safety of electronic cigarettes}}
The risks of electronic cigarette use are uncertain.<ref name="Odum20122">{{cite journal|last1=Odum|first1=L. E.|last2=O'Dell|first2=K. A.|last3=Schepers|first3=J. S.|title=Electronic cigarettes: do they have a role in smoking cessation?|journal=Journal of pharmacy practice|date=December 2012|volume=25|issue=6|pages=611–4|pmid=22797832|doi=10.1177/0897190012451909}}</ref><ref name="Harrell20142" /> This is due to there being little data regarding their [[health effect]]s<ref name="Palazzolo2">{{Citation | title=Electronic cigarettes and vaping: a new challenge in clinical medicine and public health. A literature review. | url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3859972/ | author1-first=Dominic L. |author1-last=Palazzolo | journal=Frontiers in Public Health | volume=1 |issue=56 | date=Nov 2013| doi=10.3389/fpubh.2013.00056 | pmid=24350225 | pmc=3859972}}</ref>
<nowiki> </nowiki>and to the variability of vaporizers and variability in liquid
ingredients and in their concentration and quality, and thus variability
<nowiki> </nowiki>of the contents of mist delivered to the user.<ref name="O20122">{{cite journal|last=O'Connor|first=RJ|title=Non-cigarette tobacco products: what have we learnt and where are we headed?|journal=Tobacco control|date=March 2012|volume=21|issue=2|pages=181–90|pmid=22345243|doi=10.1136/tobaccocontrol-2011-050281|pmc=3716250}}</ref><ref name="Grana20142" /><ref name="Odum20122" /> The limited evidence suggests that e-cigarettes are probably safer than traditional [[cigarette]]s.<ref name="O20122" />

They appear to be similar in [[toxicity]] to other [[nicotine replacement products]], but there is not enough data to draw conclusions.<ref name="Caponnetto20132" /> The evidence suggests that the US [[Food and Drug Administration]] (FDA) accepted products such as a [[nicotine inhaler]] may be a safer way to give nicotine than e-cigarettes.<ref name="Drummond20142" /> A July 2014 WHO report cautioned about potential risks of using electronic cigarettes.<!-- <ref name=WHOPosition2014/> -->
<nowiki> </nowiki>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."<ref name="WHOPosition20142" /> A 2014 [[systematic review]]
<nowiki> </nowiki>concluded that the risks of e-cigarettes have been exaggerated by
health authorities and stated that it is apparent that there may be some
<nowiki> </nowiki>remaining risk accompanied with e-cigarette use, though the risk of
e-cigarette use is likely small compared to smoking tobacco.<ref name="FarsalinosPolosa20142" /> {{Asof|2014}}, e-cigarettes cannot be regarded as harmless.<ref name="Pisinger20142" /> Until additional data is available on the topic, using e-cigarettes cannot be regarded as safe.<ref name="Bertholon20132">{{cite journal|last1=Bertholon|first1=J.F.|last2=Becquemin|first2=M.H.|last3=Annesi-Maesano|first3=I.|last4=Dautzenberg|first4=B.|title=Electronic Cigarettes: A Short Review|journal=Respiration|year=2013|issn=1423-0356|doi=10.1159/000353253|pmid=24080743}}</ref> No long-term studies have shown that e-cigarettes are a "healthier alternative" to traditional cigarettes.<ref name="Drummond20142" /> A 2014 review found no serious adverse effects reported in trials.<ref name="Cochrane20142" />

===Addiction===
A number of
organizations have concerns that e-cigarettes might increase addiction
to and use of nicotine and tobacco products in the young.<ref name="MMWR20132">{{cite journal|last=Centers for Disease Control and Prevention|first=(CDC)|title=Notes from the field: electronic cigarette use among middle and high school students – United States, 2011–2012|url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6235a6.htm |journal=MMWR. Morbidity and mortality weekly report|date=6 September 2013|volume=62|issue=35|pages=729–30|pmid=24005229}}</ref><ref name="DrugFacts20142">{{cite web|title=DrugFacts: Electronic Cigarettes (e-Cigarettes)|url=http://www.drugabuse.gov/publications/drugfacts/electronic-cigarettes-e-cigarettes|work=National Institute on Drug Abuse|accessdate=15 October 2014|date=September 2014|quote=There is also the possibility that they could perpetuate the nicotine addiction and thus interfere with quitting.}}</ref><ref>{{cite web|title=Citing Health Concerns the American Cancer Society Calls for Action|url=http://www.cancer.org/myacs/eastern/areahighlights/cancernynj-news-ny-ecig-health-vote|work=American Cancer Society|accessdate=12 November 2013|quote=Government agencies and medical organizations, such as the FDA, the Centers for Disease Control and Prevention, and the American Academy of Pediatrics have also expressed concern that electronic cigarettes could increase nicotine addiction and tobacco use in young people.}}</ref> This including: 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.<ref name="CDCQ&A2" /><ref name="IUATLD2">{{cite web |title=Position Statement on Electronic Cigarettes [ECs] or Electronic Nicotine Delivery Systems [ENDS] |url=http://www.theunion.org/what-we-do/publications/official/body/E-cigarette_statement_FULL.pdf |format=PDF |date=October 2013 |publisher=The International Union against Tuberculosis and Lung Disease}}</ref><ref>{{cite web|last=Korioth|first=Trisha|title=E-cigarettes easy to buy, can hook kids on nicotine|url=http://aapnews.aappublications.org/content/early/2013/10/04/aapnews.20131004-4|work=The American Academy of Pediatrics|accessdate=17 November 2013}}</ref><ref name="FDAConsumer20092">{{cite web|title=FDA Warns of Health Risks Posed by E-Cigarettes|url=http://www.fda.gov/forconsumers/consumerupdates/ucm173401.htm|work=FDA|accessdate=17 November 2013|date=23 July 2009|postscript=—Reviewed 17 September 2013}}</ref> The World Health Organization raised concern of addiction for nonsmokers from their use in July 2013.<ref name="WHOJuly20132" /> The [[National Institute on Drug Abuse]]
<nowiki> </nowiki>stated that there is a possibility that they could promote continuation
<nowiki> </nowiki>of addiction to nicotine in those who are attempting to quit.<ref name="DrugFacts20142" />


[[File:Nicotine-2D-skeletal.png|thumb|The [[nicotine]] [[molecule]].|link=https://en.wikipedia.org/wiki/File:Nicotine-2D-skeletal.png]]
It is not clear whether using e-cigarettes will decrease or increase overall [[nicotine addiction]].<ref name="Palazzolo2" /> The information concerning the drug action of the nicotine in e-cigarettes is limited.<ref name="Schroeder20142" /> The evidence suggests that the nicotine in e-cigarettes is adequate to sustain nicotine dependence.<ref name="Schroeder20142">{{cite journal|last1=Schroeder|first1=M. J.|last2=Hoffman|first2=A. C.|title=Electronic cigarettes and nicotine clinical pharmacology|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii30–ii35|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051469|pmid=24732160}}</ref> The limited data suggests that the likelihood of abuse from e-cigarettes could be smaller compared to traditional cigarettes.<ref name="Evans20142">{{cite journal|last1=Evans|first1=S. E.|last2=Hoffman|first2=A. C.|title=Electronic cigarettes: abuse liability, topography and subjective effects|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii23–ii29|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051489|pmid=24732159}}</ref> A 2014 systematic review found that e-cigarettes could cause non-smokers to begin smoking are unsubstantiated.<ref name="FarsalinosPolosa20142" /> A 2014 review found no evidence that they are used regularly by those who have never smoked,<ref name="Hajek20142">{{cite journal|last1=Hajek|first1=P|last2=Etter|first2=JF|last3=Benowitz|first3=N|last4=Eissenberg|first4=T|last5=McRobbie|first5=H|title=Electronic cigarettes: review of use, content, safety, effects on smokers and potential for harm and benefit.|url=http://tobonline.com/Media/Default/Article/Addiction-%20Hajek%2014.pdf|journal=Addiction (Abingdon, England)|date=31 July 2014|pmid=25078252|doi=10.1111/add.12659|volume=109|issue=11|pages=1801–10}}</ref>
<nowiki> </nowiki>while a 2014 review has found that in some populations nearly up to a
third of youth who have ever used electronic cigarettes have never
smoked traditional cigarettes.<ref name="Grana20142" /> No long-term studies have been done on the effectiveness of e-cigarettes in treating tobacco addiction.<ref name="Drummond20142" />
<nowiki> </nowiki>The degree to which teens are using e-cigarettes in ways it is not
intended to be used, such as increasing the nicotine delivery, is
unknown.<ref name="Durmowicz20142">{{cite journal|last1=Durmowicz|first1=E. L.|title=The impact of electronic cigarettes on the paediatric population|journal=Tobacco Control|volume=23|issue=Supplement 2|year=2014|pages=ii41–ii46|issn=0964-4563|doi=10.1136/tobaccocontrol-2013-051468|pmid=24732163}}</ref> The extent to which e-cigarette use will lead to abuse in youth is unknown.<ref name="Durmowicz20142" /> The impact of e-cigarette use by children in respect to [[substance dependence]] is unknown.<ref name="Durmowicz20142" />
==History==
==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.<ref>James Dunworth for the Ashtray Blog. 3 May 2012 [https://www.ecigarettedirect.co.uk/ashtray-blog/2012/05/history-electronic-cigarette.html The History of the Electronic Cigarette]</ref><ref>{{cite web|url=http://www.google.com/patents?id=RjlUAAAAEBAJ&printsec=abstract&zoom=4&source=gbs_overview_r&cad=0#v=onepage&q&f=false |title=US Patent 3200819. Smokeless non-tobacco cigarette|accessdate=29 February 2012}}</ref>
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.<ref>James Dunworth for the Ashtray Blog. 3 May 2012 [https://www.ecigarettedirect.co.uk/ashtray-blog/2012/05/history-electronic-cigarette.html The History of the Electronic Cigarette]</ref><ref>{{cite web|url=http://www.google.com/patents?id=RjlUAAAAEBAJ&printsec=abstract&zoom=4&source=gbs_overview_r&cad=0#v=onepage&q&f=false |title=US Patent 3200819. Smokeless non-tobacco cigarette|accessdate=29 February 2012}}</ref>
Line 156: Line 269:


==Society and culture==
==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.<ref name=NHE2014/><ref name=digitaltrends.com/> 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.<ref name=NHE2014/>
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.<ref name="NHE2014">{{cite web|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/311887/Ecigarettes_report.pdf|title=Electronic cigarettes – A report commissioned by Public Health England |publisher=[[Public Health England]]|date=15 May 2014|author1-first=John |author1-last=Britton|author2-first=Ilze|author2-last=Bogdanovica}}</ref><ref name=digitaltrends.com/> 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.<ref name=NHE2014/>


As the electronic cigarette industry grows, a [[subculture]] has emerged which calls itself "the vaping community".<ref name=digitaltrends.com/><ref>{{cite web|last=Park |first=Andy |url=http://www.sbs.com.au/news/article/2013/06/18/feed-subculture-around-e-cigarettes |title=The Feed: The subculture around e-cigarettes |publisher=[[SBS World News]] |date=26 August 2013 |accessdate=20 November 2013}}</ref> Online forums like E-Cig-Reviews.com was one of the first major communities.<ref name="trading-addictions"/> Another online forum UKVaper.org that focuses on e-cigarettes started the hobby of modding.<ref name=trading-addictions>{{cite news|title=Trading addictions: the inside story of the e-cig modding scene |url=http://www.engadget.com/2014/10/01/inside-story-e-cig-modding-uk/ |publisher=Engadget | author=Michael Grothaus | date=1 October 2014}}</ref> There are also groups on Facebook and Reddit.<ref name=pimpvape/> Members of this emerging subculture often view electronic cigarettes as a safer alternative to smoking<ref name=Hajek2014/> and some even view it as a [[hobby]]. They tend to use highly [[Customization (anthropology)|customized]] devices that do not resemble what are known, by some, as "cig-a-likes," or electronic cigarettes that resemble real cigarettes.<ref name=fremonttrib>{{cite news|title=Crutch or cure: issues surround use of e-cigarettes |url=http://fremonttribune.com/news/local/crutch-or-cure-issues-surround-use-of-e-cigarettes/article_0c7c6547-458a-5d2f-8b3c-515f2c1f1c9b.html | work=Fremont Tribune | date=9 November 2013}}</ref> Online forums on modding have grown in the vaping community.<ref name=formsgain>{{cite news|title=CVape life: welcome to the weird world of e-cig evangelists |url=http://www.theverge.com/2014/2/25/5445662/vape-life-welcome-to-the-weird-world-of-e-cig-evangelists |publisher=The Verge | author=Molly Osberg | date=25 February 2014}}</ref>
As the electronic cigarette industry grows, a [[subculture]] has emerged which calls itself "the vaping community".<ref name=digitaltrends.com/><ref>{{cite web|last=Park |first=Andy |url=http://www.sbs.com.au/news/article/2013/06/18/feed-subculture-around-e-cigarettes |title=The Feed: The subculture around e-cigarettes |publisher=[[SBS World News]] |date=26 August 2013 |accessdate=20 November 2013}}</ref> Online forums like E-Cig-Reviews.com was one of the first major communities.<ref name="trading-addictions"/> Another online forum UKVaper.org that focuses on e-cigarettes started the hobby of modding.<ref name=trading-addictions>{{cite news|title=Trading addictions: the inside story of the e-cig modding scene |url=http://www.engadget.com/2014/10/01/inside-story-e-cig-modding-uk/ |publisher=Engadget | author=Michael Grothaus | date=1 October 2014}}</ref> There are also groups on Facebook and Reddit.<ref name=pimpvape/> Members of this emerging subculture often view electronic cigarettes as a safer alternative to smoking<ref name=Hajek2014/> and some even view it as a [[hobby]]. They tend to use highly [[Customization (anthropology)|customized]] devices that do not resemble what are known, by some, as "cig-a-likes," or electronic cigarettes that resemble real cigarettes.<ref name=fremonttrib>{{cite news|title=Crutch or cure: issues surround use of e-cigarettes |url=http://fremonttribune.com/news/local/crutch-or-cure-issues-surround-use-of-e-cigarettes/article_0c7c6547-458a-5d2f-8b3c-515f2c1f1c9b.html | work=Fremont Tribune | date=9 November 2013}}</ref> Online forums on modding have grown in the vaping community.<ref name=formsgain>{{cite news|title=CVape life: welcome to the weird world of e-cig evangelists |url=http://www.theverge.com/2014/2/25/5445662/vape-life-welcome-to-the-weird-world-of-e-cig-evangelists |publisher=The Verge | author=Molly Osberg | date=25 February 2014}}</ref>

Revision as of 20:05, 20 December 2014

First generation electronic cigarette resembling a tobacco cigarette

An electronic cigarette (e-cig or e-cigarette), personal vaporizer (PV) or electronic nicotine delivery system (ENDS) is a battery-powered vaporizer which has a similar feel to tobacco smoking.[1] Electronic cigarettes do not contain tobacco, although they do use nicotine from tobacco plants.[2] They do not produce cigarette smoke but rather an aerosol (mist),[3][4] which is frequently but inaccurately referred to as vapor.[4] In general, they have a heating element that atomizes a liquid solution known as e-liquid.[5] E-liquids are usually a mixture of propylene glycol, glycerin, nicotine, and flavorings.[3] Others have similar ingredients but without nicotine.[6]

The benefits and risks of electronic cigarette use are uncertain.[7][8] One review found evidence of a benefit as a smoking cessation aid from a small number of studies.[9] Another considered the data to be inconclusive.[8] Their role in tobacco harm reduction as a substitute for tobacco products is unclear.[10] They appear to be similar in safety to other nicotine replacement products, but there is not enough data to draw conclusions.[11] The evidence suggests that the US Food and Drug Administration (FDA) accepted products such as a nicotine inhaler may be a safer way to give nicotine than e-cigarettes.[10]

The limited evidence suggests that e-cigarettes are safer than traditional cigarettes.[2] Electronic cigarettes may carry a risk of addiction in those who do not already smoke,[12] but there is no evidence of ongoing use among those who have never smoked.[13] They may promote delaying of quitting smoking, or act as a deterrent to quitting.[3] Emissions from e-cigarette may contain tiny ultrafine particles of flavors, aroma transporters, glycerol, propylene glycol, nicotine, tiny amounts of carcinogens and heavy metals, and other chemicals.[3][13] The evidence indicates the levels of contaminants do not warrant health concerns according to workplace safety standards.[14] E-cigarette emissions have fewer toxic components than cigarette smoke.[3] They are likely to be less harmful to users and bystanders.[3][13] No serious adverse effects from e-cigarette have been reported in trials.[9] Less serious adverse effects from e-cigarette use include throat and mouth inflammation, vomiting, nausea, and cough.[3]

The frequency of use has increased with up to 10% of American high school students having ever used them as of 2012 and around 3.4% of American adults as of 2011.[15] In the UK the number of e-cigarette users has increased from 700,000 in 2012 to 2.1 million in 2013. About 60% are smokers and most of the rest are ex-smokers.[16] E-cigarette users most commonly continue to smoke traditional cigarettes.[3] Current e-cigarettes arose from an invention made by Hon Lik in China in 2003,[17] and devices are mostly manufactured in China.[3] E-cigarette brands have increased advertising with similar marketing to that used to sell cigarettes in the 1950s and 1960s.[3] Because of the possible relationship to tobacco laws and medical drug policies, electronic cigarette legislation is being debated in many countries.[6][18] The European Parliament passed regulations in February 2014 requiring standardization of liquids and personal vaporizers, listing of ingredients, and child-proofing of liquid containers.[19] The US Food and Drug Administration (FDA) published proposed regulations in April 2014 with some similar measures.[20]

Usage

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 to circumvent smoke-free laws.[3]

Electronic cigarette sales increased from 50,000 in 2008 to 3.5 million in 2012.[21] Most people who use electronic cigarettes have a history of smoking cigarettes while some young people who have never smoked cigarettes have tried electronic cigarettes at least once.[15] Among adults or children, the extent to which a dual use tendency exists using e-cigarettes and traditional cigarettes is unclear.[3] E-cigarette users most commonly continue to smoke traditional cigarettes.[3] Many users report that electronic cigarettes help them either quit smoking or reduce the number of cigarettes smoked.[13] Adults most frequently use electronic cigarettes as a replacement for tobacco, but not always to quit.[15] Although some people have a desire to quit smoking by using e-cigarettes, other common explanations for the use of these products are to circumvent smoke-free laws and to cut back on traditional cigarettes.[3] Many have conveyed concern about the possibility that e-cigarettes may function as a "gateway" to using traditional cigarettes.[22] Ethical concerns exist from e-cigarettes use among minors and their possibility to weaken efforts to reduce traditional cigarette use.[22]

In the United States, as of 2011, one in five adults who smoke have tried electronic cigarettes and 3.3% are currently using them.[15][23] 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.[15] 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%.[24] The frequency of use has increased with up to 10% of American high school students having ever used them as of 2012.[15] In 2013 the CDC found a threefold increase from 2011 in the number of youth who have used electronic cigarettes who have never smoked.[25] The majority of youth who use e-cigarettes also smoke combustible cigarettes.[26]

In the UK in 2014, 18% of regular smokers identified themselves as using electronic cigarettes and 51% stated that they had used them in the past.[27] Among those who had never smoked, 1.1% said they had tried them and 0.2% continue to use them.[27] In 2013, among those under 18, 7% have used e-cigarettes at least once.[27] Among non-smokers' children, 1% reported having tried e-cigarettes "once or twice," and there was no evidence of continued use.[27] Sustained use was mostly confined to children who smoke or have smoked.[27] 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%.[28] About 60% are smokers and most of the rest are ex-smokers.[16]

A February 2014 survey in France estimated that between 7.7 and 9.2 million individuals have experimented with using electronic cigarettes, with between 1.1 and 1.9 million using on a daily basis. 67% of tobacco smokers in the survey used electronic cigarettes to reduce or quit tobacco smoking. 9% of those who experimented with electronic 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 electronic cigarettes for stopping tobacco use.[29]

Larger numbers of young people are starting to use e-cigarettes. A high number of youths who use e-cigarettes also smoking traditional cigarettes. Some youths who have tried an e-cigarette have never smoked a traditional cigarette; this indicates that they can be a starting point for nicotine use for some youths. There are high levels of dual use with e-cigarettes and traditional cigarettes.[3]

Construction

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

Most electronic cigarettes take an overall cylindrical shape although a wide array of shapes can be found: box, pipe styles etc.[30] First generation electronic cigarettes were usually designed to simulate smoking implements, such as cigarettes or cigars, in their use and appearance.[31] New generation electronic cigarettes often called mods, PVs (personal vaporizer) or APVs (advanced personal vaporizer) have an increased nicotine-dispersal performance,[31] housing higher capacity batteries,[32] and come in various form factors, including metal tubes and boxes.[32][33][34] An e-cigarette can be rigid and a bit bulky.[1] Many electronic cigarettes are composed of standardized replaceable parts that are interchangeable from one brand to the other.[35] Common components include a liquid delivery and container system like tanks or cartomizers, an atomizer, and a power source.[36] A wide array of component combinations exist .[37]

Device generations

As of 2014 there have been three generations of devices. The different generations look different from each other. They all have distinct batteries and atomizers. The atomizer and battery are connected. Common connection types are 510, 901, 808 and 801 with the 510 being the most common.

First generation

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

First generation e-cigarettes commonly look like tobacco cigarettes and are thus called "cigalikes".[31] They may be designed as a single unit that contains a battery, coil and filling saturated with e-juice in a single tube to be used and disposed of after either the battery is no longer charged or the e-liquid is depleted.[31] They may also be designed as a reusable device with a battery and cartridge called a cartomizer.[38] This is so the battery and cartridge can be separated to allow the battery to be charged when drained or the cartomizer replaced when the e-juice is used up.[31] The battery may contain an electronic airflow sensor whereby activation is triggered simply by drawing breath through the device, while other models employ a power button that must be held during operation.[38] An LED in the button or on the end may also be employed to indicate activation.[39] Charging is commonly done with a USB charger that the battery attaches to.[40] Some manufacturers also have a cigarette pack-shaped portable charging case (PCC), which contains a larger battery capable of recharging e-cigarettes batteries.[41] Reusable devices can come in a kit that contains a battery, a charger, and at least one cartridge.[41] Varying nicotine concentrations are delivered to users because of cartomizer, e-juice mixtures, and battery manufacturing differences. These hardware differences cause differences in the ingredients and their concentrations delivered to users and the surrounding air from the exhaled aerosol, even when the same liquid is used.[3]

Second generation

Second generation PV.

Second generation devices are often used by more experienced users. These devices are larger overall and look less like tobacco cigarettes.[38] They have larger non removable batteries with higher capacity.[31] They are charged with a USB charger that the battery attaches to. Some battery sections have a USB port for recharging and can be used while they are charging or a "passthrough".[42] They are usually two part devices meant to be reused and so reduce the cost of operation.[31] Second generation e-cigarettes commonly use a tank or a "clearomizer".[38] The tanks are meant to be refilled with bottles of e-juice.[31] They can also be used with cartomizers.[31] Some cheaper batteries use a microphone to activate them.[43] Other batteries, like Ego type batteries, can use a custom integrated circuit to indicate battery status on the included LED and a button for activation.[43] The power button can also used to turn the battery off and on.[44] These batteries may also have adjustable power adjustments.[38]

Third generation

Third generation PV.

Third generation devices includes mechanical mods and variable voltage devices though both are commonly called "mods" are the battery section of the device.[31] Mechanical and variable devices are commonly either cylindrical or a box.[45] They can be made of wood, aluminium, stainless steel, or brass.[45] A box can hold larger and sometimes multiple batteries.[45] Mechanical mods and variable devices use larger batteries.[46] The battery is installed in the mod and can be removed. This allows the user to change the battery when it is depleted. Variable devices often have a USB connector for recharging and can be used while they are charging as a "passthrough".[42][47] Mechanical mods do not because they do not contain circuitry. 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.[48] The power section may include additional options, such as displays and support of a wide range of internal batteries and allow different atomizers to be connected.[38] Third generation devices commonly use rebuildable atomizers allowing users to chose the wicking material.[31][38] Handmade coils can be installed in the atomizer to increase vapor production.[46] Hardware in this generation is sometimes modified to increase flavor.[49] This generation can also use clearomizers.[31] The size of the battery section allows the use of larger tanks that hold more e-liquid.[45]

Atomizer

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

An atomizer generally consists of a small heating element responsible for vaporizing e-liquid, as well as a wicking material that draws liquid in.[50] 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 then connected to the positive and negative poles of the device. When activated the resistance wire (or coil) quickly heats up thus creating a mist from the liquid, which is then inhaled by the user.[51]

The electrical resistance of the coil, the voltage output of the device, the airflow of the atomizer and the efficiency of the wick play important roles in the perceived quality of the mist coming from the atomizer. They also greatly affect the mist quantity or volume that will be produced by the atomizer.

Atomizer resistances usually vary from 1.5Ω (ohms) to 3.0Ω from one atomizer to the next but can go as low as 0.1Ω in the most extreme cases of DIY coil building. Coils of lower ohms have increased mist production but could present a fire hazard and other dangerous battery failures if the user is not knowledgeable enough about basic electrical principles and how they relate to battery safety.[52]

Wicking materials vary greatly from one atomizer to another but silica fibers are the most commonly used in manufactured atomizers. "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.[53]

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.[50] They can have up to 3 coils and each coil will increase vapour production.[50] It 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.[50] Most cartomizers are refillable even if not advertised as such.[50][54]

Cartomizers can be used on their own or in conjunction with a tank that allows more e-liquid capacity.[50] 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.[50]

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.[55] Unlike cartotanks, however, no poly-foam material can be found in them. There are a lot of different wicking systems employed inside of clearomizers to ensure good moistening of the wick without flooding the coil. Some rely on gravity to bring the e-liquid to the wick and coil assembly (bottom coil clearomizers for example) whereas others rely on capillary action and to some degree the user agitating the e-liquid while handling the clearomizer (top coil clearomizers).[50][56] The coil and wicks are typically inside a prefabricated assembly or "head" that is replaceable by the user and can contain either single or dual coils. Present day clearomizers commonly have adjustable air flow control. They also hold up to 5ml of e-liquid. Tanks can be either plastic or glass. Some flavours of e-juice have been known to crack plastic clearomizer tanks.[57]

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 by an off-the-shelf atomizer "head".[31] They are generally considered advanced devices. They also allow the user to build atomizers at any desired electrical resistance.[31] The materials needed to "rebuild" the atomizers are usually much cheaper than the usual prefabricated replaceable wick and coil assemblies used in clearomizers.

These atomizers are divided into three main categories; rebuildable tank atomizers (RTAs), rebuildable dripping atomizers (RDAs),[58] and rebuildable dripping tank atomizers (RDTAs).

Rebuildable tank atomizers (RTAs) are similar to clearomizers in that they use a tank or container to hold and bring liquid to the coil. They usually hold significantly more e-liquid than other atomizers or clearomizers. The tank can be either plastic, glass, or metal. 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. The drawbacks of Genesis style atomizers include leaking if they are not not kept upright.

Rebuildable dripping atomizers (RDAs) are atomizers where the ejuice 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.[49] A "top cap" to cover the coils with airflow holes and a hole at the top where a mouth piece can be attached. The wick is generally larger than 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 help 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.

Power

Most portable devices contain a rechargeable battery, which tends to be the largest component of an electronic cigarette.

Variable power and voltage devices

PV with variable and regulated power offering battery protection

Variable power and or voltage are personal vaporizer devices that contain a built-in electronic chip allowing the user to adjust the power that goes through the heating element.[38] They are often rectangular in shape but can also be cylindrical.[45] They usually incorporate an LED screen to display information.[59] Variable wattage lets you adjust the voltage to the coil. Variable wattage devices check the ohms of the coil and automatically adjust the voltage to get the desired power to the coil.[60] Vairable devices are either variable wattage, variable voltage or both.[42] To adjust the settings the user presses buttons or rotates a dial to make adjustments in power either up or down.[37] The amount of power has a direct relationship to the heat produced by the coil, thus changing the vapor output.[38][37] Greater heat generated by the coil increases vapor production.[37] Some of these devices include additional settings through their menu system such as: atomizer resistance checker, remaining battery voltage, puff counter, activation cut-off etc.[61]

Mechanical personal vaporizers

Mechanical PV with a rebuildable atomizer

Mechanical PVs or mechanical "mods", often called "mechs", are devices without electronic components and battery protection (apart from vent holes drilled in some mechanical devices) or voltage regulation. Because there is neither protection nor regulation, they will work either way the battery is inserted. They are activated by spring loaded or opposing magnetic mechanical switches, hence their name. They rely on the natural voltage output of a battery and the material that the mod is made of.[62]

The term "mod" was originally used instead of "modification".[31] Users would modify existing hardware to get better performance, and as an alternative to the e-cigarettes that looked like traditional cigarettes.[37] Users would also modify other items like flashlights as battery compartments to power atomizers.[45][37] Today the word mod is used to describe most personal vaporizers either bought in a store or created by the user.

They are commonly used with "low resistance" (1.0Ω ~ 0.2Ω) rebuildable atomizers.[63] Seeing that most e-cigarettes containing electronic battery protection will interpret sub ohm resistance coils as a short circuit, thus prohibiting the device from being activated, mechanical mods are among the only devices that will accept such atomizer resistances although more recent (2013) electronic devices have this possibility as well.[citation needed]

Since mechanical PVs have no power regulation and are unprotected, they require special attention on the user's part that other regulated and protected PVs do not need. Making sure that the battery does not over-discharge and that the atomizer will not require more amperage than what the battery can safely allow are the user's responsibilities.[62]

E-liquid

E-liquid, e-juice or simply "juice", refers to a liquid solution that when heated by an atomizer produces mist. The main ingredients of e-liquids are usually a mix of propylene glycol (PG), glycerin (G), and/or polyethylene glycol 400 (PEG400), sometimes with differing levels of alcohol mixed with concentrated or extracted flavourings; and optionally, a variable concentration of tobacco-derived nicotine.[11][21] The nicotine may be obtained from tobacco plants or tobacco dust.[64] Most e-cigarette liquids contain nicotine, but the level of nicotine is chosen by the consumer.[14] E-liquid that does not contain nicotine is also available.[14]

The solution is often sold in bottles or pre-filled disposable cartridges, or as a kit for consumers to make their own eJuices. Components are also available to modify or boost their flavour, nicotine strength, or concentration of e-liquid.[65] Pre-made e-liquids are manufactured with various tobacco, fruit, and other flavors,[3] as well as variable nicotine concentrations (including nicotine-free versions). The standard notation "mg/ml" is often used in labelling for denoting nicotine concentration, and is sometimes shortened to a simple "mg".[66] In surveys of regular e-cigarette users the most liked e-liquids had a nicotine content of 18 mg/ml, and largely the favorite flavors were tobacco, mint and fruit.[13] A cartridge may contain 0 to 20 mg of nicotine.[67] A refill bottle can contain up to 1 g of nicotine.[67] The flavorings may be natural or artificial.[68]

Health effects

Position of medical organizations

As of 2014 electronic cigarettes have not been approved for helping people quit smoking by any government.[69] In July 2014, a report produced by the World Health Organization (WHO) for the Conference of the Parties to 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.[69] 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.[69] A previous WHO statement from July 2013 stated that e-cigarettes have not been shown to be effective helping people quit smoking.[70] 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.[70] The World Lung Foundation applauded the 2014 WHO report's recommendation for tighter regulation of e-cigarettes due to concerns about the safety of e-cigarettes and the possible increased nicotine or tobacco addiction among youth.[71]

The UK National Health Service has concluded, "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."[72]

In 2014, the US Food and Drug Administration (FDA) concluded, "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."[73]

Smoking cessation

As of 2014, research on the safety and efficacy of e-cigarette use for smoking cessation is limited.[74] Their benefit in helping people quit smoking is uncertain.[75] A 2014 Cochrane review found that e-cigarettes can help people quit, but was based on a small number of studies.[76]

Two 2014 reviews found no evidence that e-cigarettes are more effective than existing nicotine replacement treatments for smoking cessation.[77][76] One of these reviews stated that to encourage e-cigarette use as a cessation aid in cigarette users is premature.[77] A 2013 randomized controlled trial found higher smoking cessation rates associated with e-cigarettes with nicotine than e-cigarettes without nicotine or traditional NRT patches, but the study was too small to make these results statistically significant.[78] There are some non-controlled studies which have reported possible benefit.[79] Electronic cigarettes were not regularly associated with trying to quit tobacco among young people.[80] 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.[81] This review therefore called for their use to be limited to smokers who are unwilling or unable to quit.[81] A 2014 review found four experimental studies and six cohort studies that indicated that electronic cigarettes reduced the desire to smoke and withdrawal symptoms.[82] This review also noted that two cohort studies found that electronic cigarettes led to a reduction in the number of cigarettes smoked per day.[82]

Harm reduction

Tobacco harm reduction has been a controversial area of tobacco control.[83] The health community have been cautious to support the tobacco industry to bring safer products to market that will lessen the risks related with tobacco use.[83] A 2011 review found in the fight to decrease tobacco related death and disease, e-cigarettes show great promise.[83] A 2014 review found no long-term evidence on the safety or efficacy of e-cigarettes, including whether they reduce harm for tobacco related disease or will improve the health of the population as a whole. Therefore, promotion of e-cigarettes as a harm reduction product is premature.[77] A 2014 review found e-cigarettes may be less harmful than tobacco cigarettes to users and bystanders.[84] The same review concluded that health professionals may consider advising smokers who are reluctant to quit by way of other methods to switch to e-cigarettes as a safer alternative to smoking.[84] A 2014 review argued that regulations for electronic cigarettes should be similar to those for dietary supplements or cosmetic products to not limit the potential for harm reduction with electronic cigarettes replacing tobacco.[85] 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.[86] 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.[87]

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 mist of e-cigarettes.[83] 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.[83] 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.[88] Adults most frequently use electronic cigarettes as a replacement for tobacco, but not always to quit.[80] 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.[89] Some users want to reduce harm from smoking.[90]

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.[90] 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.[91] 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.[92] 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.[93] 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."[69]

Safety

The risks of electronic cigarette use are uncertain.[94][75] This is due to there being little data regarding their health effects[95] and to the variability of vaporizers and variability in liquid ingredients and in their concentration and quality, and thus variability of the contents of mist delivered to the user.[86][89][94] The limited evidence suggests that e-cigarettes are probably safer than traditional cigarettes.[86]

They appear to be similar in toxicity to other nicotine replacement products, but there is not enough data to draw conclusions.[79] The evidence suggests that the US Food and Drug Administration (FDA) accepted products such as a nicotine inhaler may be a safer way to give nicotine than e-cigarettes.[77] A July 2014 WHO report cautioned about potential risks of using electronic 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."[69] A 2014 systematic review concluded that the risks of e-cigarettes have been exaggerated by health authorities and stated that it is apparent that there may be some remaining risk accompanied with e-cigarette use, though the risk of e-cigarette use is likely small compared to smoking tobacco.[88] As of 2014, e-cigarettes cannot be regarded as harmless.[81] Until additional data is available on the topic, using e-cigarettes cannot be regarded as safe.[96] No long-term studies have shown that e-cigarettes are a "healthier alternative" to traditional cigarettes.[77] A 2014 review found no serious adverse effects reported in trials.[76]

Addiction

A number of organizations have concerns that e-cigarettes might increase addiction to and use of nicotine and tobacco products in the young.[97][98][99] This including: 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.[93][100][101][102] The World Health Organization raised concern of addiction for nonsmokers from their use in July 2013.[70] The National Institute on Drug Abuse stated that there is a possibility that they could promote continuation of addiction to nicotine in those who are attempting to quit.[98]

The nicotine molecule.

It is not clear whether using e-cigarettes will decrease or increase overall nicotine addiction.[95] The information concerning the drug action of the nicotine in e-cigarettes is limited.[103] The evidence suggests that the nicotine in e-cigarettes is adequate to sustain nicotine dependence.[103] The limited data suggests that the likelihood of abuse from e-cigarettes could be smaller compared to traditional cigarettes.[104] A 2014 systematic review found that e-cigarettes could cause non-smokers to begin smoking are unsubstantiated.[88] A 2014 review found no evidence that they are used regularly by those who have never smoked,[84] while a 2014 review has found that in some populations nearly up to a third of youth who have ever used electronic cigarettes have never smoked traditional cigarettes.[89] No long-term studies have been done on the effectiveness of e-cigarettes in treating tobacco addiction.[77] The degree to which teens are using e-cigarettes in ways it is not intended to be used, such as increasing the nicotine delivery, is unknown.[105] The extent to which e-cigarette use will lead to abuse in youth is unknown.[105] The impact of e-cigarette use by children in respect to substance dependence is unknown.[105]

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.[106][107]

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 electronic cigarette.[17][108] Hon had himself quit smoking, after his father, also a heavy smoker, had died of lung cancer. In 2003,[109] he came up with the idea of using a piezoelectric ultrasound-emitting element to vaporise a pressurized jet of liquid containing nicotine diluted in a propylene glycol solution.[110] This design produces a smoke-like vapour 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 placing it in a disposable plastic cartridge which serves as a liquid reservoir and mouthpiece.

Hon patented the modern e-cigarette design in 2003. Electronic cigarettes using a different design 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.[17] 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[17] before receiving its first international patent in 2007.[111]

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.[112] This is a mechanism which integrates the heating coil into the liquid chamber. The new device was launched in the UK in 2007 in their Gamucci brand and 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.[113]

The international tobacco companies, recognising the development of a potential new market sector that could render traditional tobacco products obsolete,[114] are increasingly involved in the production and marketing of their own brands of e-cigarettes and in acquiring existing e-cigarette companies.[115] Blu, a prominent US e-cigarette producer, was acquired by Lorillard Inc. in 2012.[116] 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.[117][118] On October 1, 2013 Lorillard Inc. acquired another e-cigarette company, this time a UK based company SKYCIG.[119] 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 and $20 million in incentive payments.[120] Altria also markets its own e-cigarette, the MarkTen, while Reynolds American has entered the sector with its Vuse product.[115]

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.[121][37] 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.[121]

As the electronic cigarette industry grows, a subculture has emerged which calls itself "the vaping community".[37][122] Online forums like E-Cig-Reviews.com was one of the first major communities.[45] Another online forum UKVaper.org that focuses on e-cigarettes started the hobby of modding.[45] There are also groups on Facebook and Reddit.[49] Members of this emerging subculture often view electronic cigarettes as a safer alternative to smoking[13] and some even view it as a hobby. They tend to use highly customized devices that do not resemble what are known, by some, as "cig-a-likes," or electronic cigarettes that resemble real cigarettes.[123] Online forums on modding have grown in the vaping community.[124]

Large gatherings of vapers, called vape meets, are happening around the United States which focus around e-cig devices, accessories, and the life style that accompanies them.[37] Vapefest, which started in 2010, is an annual show that goes to different cities.[49] 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.[37] 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 available.[125]

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 of less than 1 ohm.[126] This practice is known as "cloud-chasing". By using a coil at less that 1 ohm the batteries of PVs are stressed considerably more than what could be considered regular use and could represent a risk of dangerous battery failures.[46] 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.[127] The Oxford Dictionaries' word of the year for 2014 is 'vape'.[128]

The emerging phenomenon of electronic cigarettes has raised concerns among the health community, pharmaceutical industry, health regulators and state governments.[6] Some jurisdictions are now prohibiting or regulating the use of e-cigarettes in public spaces.

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.[18] Current regulations vary widely, from regions with no regulations to others banning the devices entirely.[18] For example, some countries such as Brazil, Canada, Singapore, the Seychelles, and Uruguay have banned e-cigarettes.[3] E-cigarettes have been listed as "drug delivery devices" in several countries because they contain nicotine, and their advertising has been monetarily restricted until safety and efficacy clinical trials are conclusive.[67] E-cigarettes are regulated as a medical device in some countries, but are not permitted to be used as a cessation aid to help smokers quit.[129]

In the fall of 2013, the electronic cigarette industry ran "a determined lobbying campaign, marrying corporate interests in a fledgling but fast-growing industry with voices elicited from the general public" to defeat proposed European legislation to regulate e-cigarettes like medical devices.[130] 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.[131]

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.[19][132]

In April 2014 the US FDA published proposed regulations for e-cigarettes along similar lines.[133][134]

In March 2014 Western Australia banned sale of electronics cigarettes.[135]

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.[136] The first advert to take advantage of the change, promoting KiK Electronic Cigarettes, aired on the day it came into force.[137]

Economics

Hon Lik, the inventor of the modern electonic 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."[138] 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).[138] Hon Lik's 2003 patents were purchased by Imperial Tobacco in 2013, for $75 million.[138]

E-cigarette devices are mostly manufactured in China. 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.[3]

Tobacco manufacturers initially dismissed electronic cigarettes as a fad; however, the purchase of blu by Lorillard for $135 million in April 2012 signaled their entry into the market. A national 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 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.[139]

According to Nielsen Holdings, convenience store e-cigarette sales 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.[140] 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 for vapor products.[141] 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."[3]

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.[142][143] States with large populations, such as New York and California, are affected to a greater degree than others.[143]

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.[144] 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.[145] A 2014 review stated that "these products need to be adequately regulated, primarily to protect users."[6]

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.[146][147] In September 2014 a product based on this - named Voke - obtained approval from the United Kingdom's Medicines and Healthcare Products Regulatory Agency.[148]

Philip Morris International (PMI) bought the rights to a nicotine pyruvate technology developed by Jed Rose at Duke University.[149] The technology is based on the chemical reaction between nicotine acid and a base, which produces an inhalable nicotine pyruvate mist.[150]

HeatSticks is a heated tobacco product marketed under the brand Marlboro by PMI.[151]

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