The team claim to have “evaluated emissions [for] aldehydes and flavouring chemicals in e-cigarette vapour under typical usage conditions”. In doing so they discovered chemicals like formaldehyde, acetaldehyde, acrolein, crotonaldehyde, butyraldehyde, diacetyl, 2,3-pentanedione, 2,3-heptanedione, 2,3-hexanedione, and 3,4-hexanedione in every sample – even though they claim to have run the study to replicate normal vaping conditions using disposable cigalikes.
The chemicals are on the two lists not just for concerns about possible carcinogenic effects. There are also: “Non-cancerous effects such as airway constriction, eye irritation, damage to airway epithelium, and alterations in gene expression.”
Eagle-eyed vapers with excellent memories might recall seeing lead author Joseph Allen’s name before. In 2015, Allen was behind the study that blew up across many newspapers and TV news channels, after his research team claimed to have proved that diacetyl was present in more than 75% of eliquids. For a couple of months it became difficult to hear news about vaping that didn’t include the phrase “popcorn lung”.
While Professor Brad Rodu said, at the time, that he too advised avoiding buttery-flavoured juices, he remained critical of Allen’s methodology: “As I advised previously, vapers should only use liquids that are certified to be free of buttery flavours that are suspected respiratory toxicants. However, laboratory investigations of e-cigarettes should use validated methods to assure credibility. The results of the Harvard Buttery Flavour Study do not meet this standard.”
Allen continued to beat his flavouring chemicals drum earlier this year, too. It’s almost as if he is on a mission. In this study, although Allen altered the puff duration down to two-second puffs, a dramatic improvement on the one in 2015, he is still sticking to a testing regime based on smoking machines and not accommodating for time it takes a wick to absorb liquid – in this case “The TE-2B Smoking Machine smoking protocol complies with the Federal Trade Commission Method for machine smoked cigarettes”.
Consequently, “At least one aldehyde was detected in every e-cigarette sampled,” and “Formaldehyde was detected in 92% of e-cigarette samples tested.” Formaldehyde is only a product of a dry-burn situation.
At least the team identify that raising the coil temperature or dropping the flow of liquid correlates to aldehyde production and that there is no standard test procedure for electronic cigarettes. As a result, it is difficult to see what this paper adds to our knowledge about vaping and relative safety.