Formaldehyde levels in e-cigarettes were previously ‘underestimated’, researchers find

Woman eith e-cigarette exhaling a cloud of vapour

The amount of a new form of the carcinogen formaldehyde found in e-cigarette aerosol emissions may have been previously underestimated according to a study published in Scientific Reports (online, 15 May 2018)[1]
. This form of formaldehyde may also serve as a delivery agent that deposits more deeply in the lungs than gaseous formaldehyde (HCHO).

The researchers originally carried out an investigation into e-cigarettes in 2015, when they reported the discovery of new hemiacetals derived from the reaction of formaldehyde and the solvents found in e-liquids. They found that these hemiacetal derivatives (1a-d) constituted a significant proportion of potentially undetected formaldehyde.

However, at the time, the research was questioned by those claiming that the results were obtained under conditions that were “averse to vapers”, because the device power level was too high, resulting in an unpleasant, burnt taste that would not appeal to vapers.

The authors, therefore, decided to revisit the investigation and carry out the analysis at an intermediate power level, claimed to be “non-averse”, “normal” usage.

They found that both HCHO and 1a-d were still produced at levels above US Occupation Safety and Health Administration workplace limits.

Furthermore, the amount of 1a-d found, was higher than the levels found in their initial 2015 study, despite the higher power used in the older study, leading the researchers to conclude that the levels of 1a-d in the 2015 paper were “underestimated”, perhaps due to their previous method which resulted in a significant amount of aerosol being lost to the ambient atmosphere.

They also confirmed their original findings that formaldehyde hemiacetals, a new form of formaldehyde, may serve as delivery agents that deposit more deeply in the lungs than gaseous formaldehyde.

“The variability in the subjective evaluation of aerosols by users, as well as factors influencing discrepant interlaboratory levels of emissions, are significant current issues in the e-cigarette field that require extensive further study,” the authors concluded.


[1] Salamanca J, Meehan-Atrash J, Vreeke S et al. E-cigarettes can emit formaldehyde at high levels under conditions that have been reported to be non-averse to users. Sci Rep 2018;8:7559. doi: 10.1038/s41598-018-25907-6

Last updated
The Pharmaceutical Journal, Formaldehyde levels in e-cigarettes were previously 'underestimated', researchers find;Online:DOI:10.1211/PJ.2018.20204898

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