Washington DC: Electronic cigarettes come in enticing flavours like "cherry crush" and "vivid vanilla," but now a team of researchers has shed some light on whether or not those ingredients are safe enough for the lungs.
Cherry flavoured e-cigarettes may expose vapers to significantly higher levels of the respiratory irritant benzaldehyde than other flavours, suggests the laboratory study.
The doses inhaled with 30 puffs were often higher than those breathed in from a conventional cigarette, the findings show.
Benzaldehyde is routinely used in foodstuffs and cosmetics and is a key ingredient in 'natural' fruit flavourings, but it has been shown to irritate the airways in animal and workplace exposure studies.
The 145 e-cigarettes were grouped according to their labelling: berry/tropical fruit (40); tobacco (37); alcohol (15); chocolate/sweet (11); coffee/tea (11); mint/menthol (10); cherry (10); and 'other' (11).
Benzaldehyde was detected in 108 out of 145 e-cigarettes, with the highest levels detected in the cherry flavoured products. Yields of the chemical were around 43 times higher than in these products.
The researchers wrote that although e-cigarettes may be a promising harm reduction tool for smokers, the findings indicate that using these products could result in repeated inhalation of benzaldehyde, with long term users risking regular exposure to the substance.
The study is published online in Thorax.