The study “Benzene formation in e-cigarettes”, was published last week in the journal PLoS One, and was followed by a statement saying that vapers are exposing themselves to a significant risk as benzene exposure via e-cigarettes was found to be of a worrying level.
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Enter Dr. Konstantinos E. Farsalinos, M.D., who is a research fellow at the Onassis Cardiac Surgery Center in Athens, and at the Department of Pharmacy, University of Patras, and is renowned for conducting laboratory and clinical research on e-cigarettes as principle investigator since 2011. He called this study “a disappointment for the scientific community.“ and whilst explaining the study in great depth, he pointed out that there is an inconsistency between the data collected by the study and the press statement.
“First of all, the study was performed based on the finding of high levels of benzoic acid in JUUL (about 45 mg/mL or 4.5%). JUUL is a prefilled e-cigarette with very high levels of nicotine (they found 6% nicotine, i.e. 60 mg/mL) which protonates nicotine with the use of acid (benzoic acid). It is unique for JUUL to use so high levels of benzoic acid; the authors mention they tested commercial liquids and found benzoic acid at levels of 0.02-2 mg/mL (0.002-0.2%). Benzoic acid could be transformed to benzene, but the study found NON-DETECTED levels of benzene in JUUL despite the use of 5 seconds puff duration.” explained Farsalinos.
He added that they tested some variable wattage devices, using custom-made liquids containing benzoic acid and benzaldehyde, and used a very high puff duration for mouth to lung vaping (5 seconds puffs). Additionally the researchers reported a liquid consumption of of 24 mg per puff at 25 W, which as Farsalinos pointed out, would be an unbearable level for a vaper doing mouth to lung vaping.
“Going back to basic physics, it is the energy (W x s = Joule) that defines whether the liquid will overheat and generate dry puffs. I explained that in detail in the study evaluating aldehyde emissions in realistic and dry puff conditions. In fact, I performed that study as a response to the famous “Hidden formaldehyde” research letter, which was authored by the same researchers as this benzene study. So, although there is no excuse for researchers to forget basic laws in physics, this is twice inexcusable because we repeated the physics in our paper quite recently (just 2 years ago).” said Farsalinos.
Numbers taken out of context
He goes on to list in great detail the numbers obtained from the study pertaining to the levels of benzene extracted from the vaping devices the researchers used, and pointed out that when taking all variables in consideration one would need to consume an exaggerated amount of e-liquid just to be exposed to the same level of benzene found in ambient air.
“Humans take about 12 breaths per minute, i.e. 17,000 (thousand) breaths per 24 h. The volume of air inhaled in 24 h is 20 m3. So, the daily exposure to benzene from ambient air is 20 μg. Even if you assume that Subtank at 25 W with 5-second puffs represent realistic conditions (they are not), you need to consume 105 mL e-liquid per day in order to be exposed to the same levels of benzene as breathing ambient air. For the EVOD under normal vaping conditions, you need to vape 125 mL e-liquid per day.”
Dr. Farsalinos refers to a particular sentence in the press statement where the researchers said,” The power levels used in the study were still far below those accessible to users on some devices, which can exceed 200 watts.” He points out that this sentence equates to saying “Eating 5 kg of vegetables in one meal can lead to death, but that is still below the tens of kg available in grocery store where customers buy their vegetables”.
No Benzene formation in e-cigarettes
The anti-tobacco activist continued by saying that although this is not the first time that a fatal error in translating data has been made, unfortunately this will not stop this misinformation from spreading and causing more damage. He pointed out that scientists keep ignoring the dry puff phenomenon “and instead of them verifying realistic conditions in their experiments, they consider theoretical the criticism they get for their own omission! “ he called this study a disappointment, and ended his article by saying “In conclusion: “Benzene formation in e-cigarettes: it does not exist…”