In the most comprehensive chemical comparison to date between smoke and e-cigarette emissions, toxicant levels in e-cigarette vapour was found to be on average 95% less than in conventional cigarette smoke.
A comparison between the vapour from Vype ePen - a commercially available e-cigarette - and 3R4F - a reference cigarette - revealed substantial reductions in the e-Pen emissions for all toxicant groups measured. Most cigarette smoke toxicants could not be detected in the e-cigarette vapour.
The results are published today in Chemical Research in Toxicology DOI: 10.1021/acs.chemrestox.6b00188.
'There are few publications examining the broad chemical composition of e-cigarettes, with most focusing on specific compounds or compound groups,' says Dr Kevin McAdam, Head of Research for Next Generation Products at British American Tobacco. 'But,' he says, 'we have tested for a total of 142 compounds, including those listed by the US Food and Drug Administration as harmful or potentially harmful (HPHC), those compounds listed by the World Health Organisation, and Health Canada, and those reported previously to be generated by e-cigarettes.'
The products tested were Vype e-Pen Blended Tobacco flavour and the Kentucky Reference Cigarette 3R4F. The products were puffed using puffing robots in separate rooms and the emissions collected. Because the levels of some constituents in e-cigarette vapour were anticipated to be very low, the air was also tested to identify contamination and analytical artefacts.
Independent contract labs were commissioned to quantify the following emissions: carbon/nitrogen oxides, carbonyls/dicarbonyls, alcohols/di-alcohols, phenols, o-heterocycles, chlorinated dioxins/furans; volatile, substituted and, polynuclear aromatic hydrocarbons; amides, azines, aromatic and aliphatic amines, nicotine & related compounds, nitrosamines, metals and radionuclides (shown below).
Comparison of toxicant emissions between Vype e-Pen and 3R4F were conducted on a per-puff basis. The results revealed average reductions of 99% for WHO and FDA truncated lists, and over 92% for the full FDA HPHC list.
Four aerosol constituents were measured at higher per-puff levels in e-cigarette vapour than from 3R4F - propylene glycol (PG), vegetable glycerine (VG), menthol and chromium. PG and VG are used to make e-liquid and menthol is used as a flavour. 'We expected to see PG and VG and menthol in the aerosol as they are used to make e-liquid (menthol is used as a flavouring)' according to Dr Kevin McAdam, Head of Research, Next Generation Products, British American Tobacco The presence of chromium was attributed to the nichrome wire used for the heating element, but daily exposures were estimated to be lower than that from smoking.
These and other tests form part of a suite of tests being developed to test novel tobacco and nicotine products and could be used to help develop standards for these products in the future.
Many in the public health community believe e-cigarettes offer great potential for reducing the public health impact of smoking. Public Health England, an executive body of the UK Department of Health, recently published a report saying that e-cigarettes are 95% safer than cigarettes. The Royal College of Physicians have said that the public can be reassured that e-cigarettes are much safer then smoking and that they should be widely promoted as an alternative to cigarettes. Cancer Research UK, Action on Smoking and Health and the British Heart Foundation are also of the view that e-cigarettes are substantially less harmful than smoking.