WashingtonD.C. (USA), Oct. 5 : In a comprehensive chemical comparison between smoke and e-cigarette emissions, researchers have found that toxicant level in e-cigarette vapour was 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.

Head researcher Kevin McAdam said, "There are few publications examining the broad chemical composition of e-cigarettes, with most focusing on specific compounds or compound groups. Butwe 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 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 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, in the smoke emission.

Comparison of toxicant emissions between Vype e-Pen and 3R4F were conducted on a per-puff basis.

The results revealed average reductions of 99 percent for WHO and FDA truncated lists, and over 92 percent 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)" said McAdam.

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 also believe e-cigarettes offer great potential for reducing the public health impact of smoking.

The results were published in Chemical Research in Toxicology DOI. (ANI)