E-cigarettes an evidence update A report commissioned by Public Health England

E-cigarettes: an evidence updatenicotine than cigarette exhalations [78]. Estimating environmental nicotine exposure,however, has to take into account the fact that side-stream smoke (ie the smoke fromthe lighted end of the cigarette, which is produced regardless of whether the smoker ispuffing or not) accounts for some 85% of passive smoking and there is no side-streamEC vapour. A study measuring nicotine residue on surfaces in houses of smokers andvapers reported only negligible levels from vaping, 169 times lower than from smoking[79].Colard et al., 2015 describe a model for estimating environmental workplace exposure[80]. The model predicts much lower nicotine exposure from vaping than from smoking,at levels negligible in health terms.Goniewicz and Lee 2014 found that nicotine from EC vapour gets deposited onsurfaces, but at very low levels [81]. This poses no concerns regarding exposure tobystanders. At the highest concentration recorded (550 μg/m 2 ), an infant would need tolick over 30 square metres of exposed surface to obtain 1mg of nicotine.Ballbe et al., 2014 provide the most informative data collected to date as this studymeasured the actual levels of airborne nicotine in homes of ex-smokers who live eitherwith smokers (N=25) or with vapers (N=5) and also in 24 control homes [82]. The studyalso measured salivary and urinary cotinine in partners of smokers and vapers. Asexpected, there was little nicotine in non-smokers’ homes. The air in the homes ofvapers contained six times less nicotine than the air in the homes of smokers. Therewas less of a difference between cotinine levels of partners of vapers and smokers (1.4to 2 fold difference), most likely due to some ‘ex-smokers’ still occasionally smoking, buteven with this possible contamination, the nicotine levels absorbed via passive vapingwere negligible. Partners of vapers had mean cotinine concentrations of 0.19 ng/ml insaliva and 1.75 ng/ml in urine, which is about 1,000 times less than the concentrationsseen in smokers and similar to levels generated by eating a tomato [83].SummaryEC release negligible levels of nicotine into ambient air with no identified health risks tobystanders.Nicotine in e-liquidsFourteen studies tested more than 400 different e-liquids, mainly to check the accuracyof product labelling. Their results are summarised in Table 6, updated from an earlierreview by Cheng et al., 2014 [84].65