E-cigarettes emit very high formaldehyde levels only in conditions that are aversive to users: A replication study under verified realistic use conditions

Konstantinos E. Farsalinos a, b, c, Vassilis Voudris a, Alketa Spyrou a, Konstantinos Poulas b

a. Department of Cardiology, Onassis Cardiac Surgery Center, Sygrou 356, Kallithea 17674, Greece
b. Department of Pharmacy, University of Patras, Rio-Patras 26500, Greece
c. National School of Public Health, Greece

Received 18 July 2017, Revised 18 August 2017, Accepted 28 August 2017, Available online 31 August 2017

Source DOI: https://doi.org/10.1016/j.fct.2017.08.044

Highlights

Formaldehyde is produced by thermal degradation in e-cigarettes.
Dry puffs result from overheating and create an unpleasant taste that users avoid.
In realistic conditions, formaldehyde in e-cigarettes is lower than cigarette smoke.
High levels of formaldehyde are produced in unrealistic (dry puff) conditions.
Dry puffs should be avoided in the laboratory setting.

Abstract

Purpose

In 2015, a study identified 5–15-fold higher levels of formaldehyde emissions from an old-generation e-cigarette working at 5.0 V compared to tobacco cigarettes. We set to replicate this study using the same e-cigarette equipment and e-liquid, while checking for the generation of dry puffs.

Design

Experienced e-cigarette users (n = 26) took 4 s puffs at different voltage settings and were asked to report the generation of dry puffs. Formaldehyde emissions were measured at both realistic and dry puff conditions.

Results

Dry puffs were detected at ≤4.2 V by 88% of participants; thus, 4.0 V was defined as the upper limit of realistic use. Levels ranged from 3.4 (SE = 2.2) μg/10 puffs at 3.3 V to 718.2 (SE = 58.2) μg/10 puffs at 5.0 V. The levels detected at 4.0 V were 19.8 (SE = 5.6) μg/10 puffs. At 4.0 V, the daily exposure to formaldehyde from consuming 3 g of liquid with the device tested would be 32% lower compared to smoking 20 tobacco cigarettes.

Conclusions

The high levels of formaldehyde emissions that were reported in a previous study were caused by unrealistic use conditions that create the unpleasant taste of dry puffs to e-cigarette users and are thus avoided.