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05 May 2014
Formaldehyde release in e-cigarette vapor. The New York Times story explained in detail
Dr Farsalinos
A study to be published in Nicotine and Tobacco Research was featured in the New York Times and has generated a lot of interest. The article mentioned that e-cigarette vapor can be the source of carcinogens, depending on the heating process.
The article is true and expected. We know that thermal degradation can lead to the release of toxic chemicals. And we know that formaldehyde, acetaldehyde and acrolein have been found in vapor. There is nothing new to it. However, this study found that levels may approach those present in tobacco cigarettes. Of course there some inaccuracies in the NYT article, such as that nicotine gets overheated (which means nothing).
Herein, I present with more detail the results of this study. Researchers used an EGO Twist battery (variable voltage) and a top-coil clearomizer (with unknown resistance, thus unknown wattage delivery). At 3.2 and 4.0 volts, formaldehyde levels were 13-807 times lower compared to tobacco cigarettes!! At 4.8 volts, formaldehyde levels were increased by up to 200 times, and reached to levels similar to tobacco cigarettes.
The main criticism to this study is that in my opinion it is highly unlikely that a top-coil atomizer like the one used in this study would be used at 4.8 volts. At a resistance of 2.2 Ohms that would represent 10.4 watts of energy delivery to the atomizer. I tried 10 watts with an EVIC battery in a Vivi Nova top-coil atomizer (for a clinical study i perfomed few months ago), and many vapers were unable to use it due to the dry puff phenomenon. Unfortunately, the researchers did not measure and could not provide any information about the resistance of the atomizers, thus it is unknown how much energy was delivered to the atomizer. In my opinion, this is crucial. Moreover, it is very important to examine new-generation (rebuildable or bottom coil) atomizers at similar conditions, since it is more likely for vapers to use such advanced atomizers for high-wattage vaping. I am certain that, due to better liquid resupply to the resistance and wick, the results will be much more favorable.
Another important point is that, although formaldehyde levels can be similar to tobacco, several other toxic chemicals are completely absent from e-cigarette vapor. For example, acrolein was completely absent although they used liquids with glycerol as the main ingredient. In fact, glycerin-based liquids had much lower formaldehyde levels in vapor compared to PG or PG/VG liquids, suggesting that they are much safer to use. As a general remark, finding few chemicals at similar levels does not mean that the risk is equivalent to tobacco cigarettes. Of course, all this information was not presented in the NYT article.
Concerning the remarks about dripping, we should admit that dripping does not allow the user to see how much liquid is present in the atomizer. The same happens with cartomizers. We currently do not know whether the elevation in formaldehyde levels happens just at the time of dry puff phenomenon, or it happens earlier (before being detected by the vaper). Clearomizer-type atomizers (also called tank systems) seem to be the future in e-cigarette use, giving consumers the ability to know when they need to resupply the atomizer with liquid.
SURSA.
Dupa cum bine observati, vapat la 3.2 si 4.0 volti, nivelul de formaldehida (iritant si cancerigen) este de 13-807 ori mai mic decai in tigarile clasice. In schimb la 4.8 volti, nivelul creste de 200 de ori, ajungand cat intr-o tigara clasica.
Deci atentie la vapatul extrem, precum se vede, vapatul poate fi bun sau rau, functie de ce parametrii de vapat alegi.
Partea a doua este un raspuns dat la recentul studiu japonez, nu foarte pozitiv la adresa vapatului. Raspunsul este oferit sa zic asa de partizanii vapatului, deci trebuie privit ca atare. Dar merita citit.
27 November 2014
By Dr Farsalinos
Today my e-mailbox is full of messages discussing about the great issue of carcinogens being at 10 times higher levels in e-cigarettes compared to tobacco cigarettes. There is a quote from Naoki Kunugita, a researcher at the Department of Environmental Health-National Institute of Public Health in Japan, about this: "In one brand of e-cigarette the team found more than 10 times the level of carcinogens contained in one regular cigarette".
Interestingly, while all news-media discuss about carcinogens (plural), the text mentions only formaldehyde. To tell the whole truth, this “substance found in building materials and embalming fluids” is in reality present everywhere in the environment, in every house, in every city, town, village, urban or rural area. So, all the noise in the newsmedia is about one carcinogen, not some carcinogens. Moreover, the title is nothing but misleading since they found the formaldehyde at “10 levels higher than cigarettes” in 1 of the 10 products tested, not in every case.
However, there is a more interesting story behind this. I immediately contacted Prof. Kunugita to ask the results of their studies. His response was immediate, mentioning the list of published studies from which he got the results. In fact, the results of analysis of 13 Japanese brands were presented in a table 1 in a recent review on carbonyls generated from e-cigarettes, published in International Journal of Environmental Research and Public Health. The results are shown in the table below.
A study by Canadian researchers in 2008 evaluated the levels of formaldehyde in mainstream cigarette smoke. As shown below, the levels were on average 200μg/cigarette, which is 6 times higher than the highest value (34μg) found in e-cigarette aerosol by Kunugita. Moreover, the study showed a much higher level of formaldehyde in sidestream smoke (>800μg/cigarette).
While we still need to see the levels of carbonyls generated from high-power e-cigarette use (using appropriate atomizers of course), the message concerning all this media frenzy is clear. Even in the worst-case Japanese product, e-cigarette aerosol contained 6 times lower formaldehyde levels compared to tobacco cigarette smoke. Where does the “10 times higher than smoking” statement comes from? I have no idea.
Of course, discussion about the maximum levels of a single product is scientifically inappropriate. We should examine the average levels of formaldehyde present in e-cigarette aerosol. The Japanese team of researcher present in the table (shown above) the number of samples (column 2) and the respective results. The average levels of formaldehyde found in all samples was calculated at 4.2μg/10 puffs. Therefore, on average, the levels of formaldehyde in e-cigarettes are up to 50 times lower compared to tobacco cigarette smoke.
Obviously, we have to realize that focusing the discussion on one of the tens of carcinogens present in tobacco cigarette smoke is misleading. Even if e-cigarettes contained similar, or higher, levels of formaldehyde, they do not contain the majority of other toxic and carcinogenic substances present in cigarette smoke. Overall, any residual risk from e-cigarette use is orders of magnitude lower than smoking. This is exactly what smokers need (and deserve) to know.
***************************** UPDATE ******************************
After my comment, Prof Kunugita contacted me again. He mentioned that the newsmedia reports refer to a recent evaluation of a newer-generation device, in which he found 1600μg formaldehyde per 15 puffs. It is true that this level is 10 times higher than what is present in tobacco cigarettes. However, this is an unpublished result, a single extreme case out of the many products he tested, and we do not know what went wrong in that case (e.g. high power levels, low levels of liquid inside, malfunctioning device etc). Still, the media frenzy is completely inappropriate.
This confusion shows why it is important for a new, systematic evaluation of aldehydes release, taking into consideration realistic conditions and puffing patterns together with evaluation of temperatures of evaporation. This is exactly what we are preparing to do, starting in a few days.
SURSA.
Cred ca e bine sa fim informati. Petru a sti cum ne putem proteja, daca putem.
Din 
