Today we offer a translation of Konstantinos Farsalinos’ reaction to an alarmist study on benzene. A press release associated with the publication of this study is creating a media buzz.
A study recently published in the scientific journal PLoS One[1] is entitled:”Benzene formation in e-cigarettes”. A press release, a decidedly trendy habit in electronic cigarette research, also accompanied the release of this study. This press release discusses the enormous risk associated with benzene in the use of electronic cigarettes[editor’s note:”Carcinogenic benzene found in high-powered electronic cigarettes”]. And it is very interesting to note, once again, the inconsistencies between a study and its press release.
Benzoic acid added to e-liquids
This study was conducted based on the benzoic acid results found in JUUL [editor’s note: a rectangular electronic cigarette in the shape of a USB flash drive, very popular in the United States]. JUUL is an e-cigarette with pre-filled cartridges containing very high levels of nicotine (they found 6% nicotine, or 60mg/ml) increased by protonation with benzoic acid. It is unique for JUUL to use such high levels of benzoic acid.
The authors mention that they tested commercially available e-liquids and found benzoic acid at 0.02-2 mg/ml (0.002-0.2%) levels. Benzoic acid can be converted to benzene, but the study found no trace of benzene in JUUL despite 5-second puffs.
JUUL is not a variable power device, so it was impossible to raise it to temperatures high enough to cause the appearance of benzene (or other chemical compounds). They then tested other variable power devices (with 1.8 Ohm single coil and Subtank 1.2 Ohm atomizers) using homemade liquids containing benzoic acid and benzaldehyde.
Curious experimental conditions
The authors of the study used 5-second puffs (which is a very long duration for indirect inhalation enthusiasts – mouth to lung – MTL). It was used at 13 W (on 5-second puffs), which is an extreme value.
Interestingly, the authors mention that the recommended setting is 6 W. The Subtank was used at 25 W, which may be within the recommended settings but not for 5-second puffs. Even 4-second puffs would be very long for such a Subtank setting.
It should also be noted that the authors report an e-liquid intake of 24 mg per puff at 25 W, which would be unbearable for a direct inhalation vape. For these two devices, despite the fact that the levels of benzoic acid found in commercial e-liquids were 0.02-2 mg/ml, the researchers still added 9 mg/ml of benzoic acid in their homemade e-liquid, as well as 10 mg/ml of benzaldehyde, a well-known aromatic component.
If we go back to the basics of physics, it is the energy (W x s = Joule) that defines whether a liquid will overheat and generate dry hits. I explained this in detail in this study, which evaluates aldehyde emissions under realistic and dry hit conditions. In fact, I did this study in response to the famous scientific letter “Hidden Formaldehyde”, signed by the same authors as the study we are talking about today on benzene. While there is no excuse for forgetting the fundamental principles of physics, this is all the less excusable as we have repeated these rules in our recent publications (just two years ago).
The results of this study are very interesting. With the recommended setting of 6 W on the atomizer (I repeat, for 5-second puffs), researchers found between 0 and 0.16? g/g benzene (keep these numbers in mind). At 13 W (risk of dry hit), they found up to 24? g/g. With the Subtank, rates range from 0 to 0.19? g/g, even at very high powers.
What do these results show? It depends on how you look at it. The authors calculated concentrations of benzene in inhaled vapor, and reported levels up to 5000? g/m3 of air (on dry hits of course). Compared to the ambient air analyses of 1? g/m3, everyone would think it’s a disaster. But not really.
Kommentek
Kommenteléshez kérlek, jelentkezz be: