I finally found an experiment done to determine the output of formaldehyde and other carbonyls from vaping, where the scientists actually knew enough about vaping to design a realistic and useful experiment. Unlike all the other experiments I've found, THIS experiment relates the carbonyl output to the actual coil temperature, measured while wet, using infrared photography.
Formaldehyde is the principal carcinogen found in eJuice vapor, and is also in tobacco smoke. It is created when glycerol (VG) and propylene glycol (PG) are heated to the point where they partially oxidize. VG creates more of this than PG does.
Studies based on wattage are meaningless because for a given wattage, different coils produce different cooking temperatures. It's the temperature that determines the extent of oxidation of VG and PG into the unhealthy carbonyls, not the wattage alone.
The net of this experiment is that wet coil temps between 400 - 480 deg. F produce less formaldehyde than cigarette smoke (comparing 15 puffs of eJuice vs. 1 low tar cigarette). The formaldehyde production increases dramatically over 550 deg. F.
Since I read this experiment (I'm not a chemist, but I took a few chem. courses in college, enough to follow this), I've started to set my AVP with temperature control to vape at 450 deg. F. I was vaping at 550. The taste and cloud temperature is still good. Speaking of taste, they actually had regular vape users sample cloud taste at the different wattage levels used in the experiment. Here is the link to that experiment:
Correlation of volatile carbonyl yields emitted by e-cigarettes with the temperature of the heating coil and the perceived sensorial quality of the generated vapours
In particular, check out the formaldehyde outputs by wattage graph (3.2), then further down see the wet coil temperature by wattage graph (3.4.2).
In order to vape safely, based on this study, I recommend using an AVP unit with Temperature Control, set between 400 - 475 deg. F. These units let you set the max coil temperature for various coil metals of known thermal coefficients of resistance (TCR). My unit, a Presa 100W by Wismec, lets me program any value of TCR from 0 - 1000. I am currently using it with a 1.2 ohm kanthal coil, and looked up the TCR of kanthal = 2. At this low TCR value, my unit resets itself occasionally, and I have to set it back from VW mode to TCR mode again. But this does not happen with higher TCR values, like 316L Stainless with TCR = 92.
Safe vaping; or live long and puff!
-Kurt
Formaldehyde is the principal carcinogen found in eJuice vapor, and is also in tobacco smoke. It is created when glycerol (VG) and propylene glycol (PG) are heated to the point where they partially oxidize. VG creates more of this than PG does.
Studies based on wattage are meaningless because for a given wattage, different coils produce different cooking temperatures. It's the temperature that determines the extent of oxidation of VG and PG into the unhealthy carbonyls, not the wattage alone.
The net of this experiment is that wet coil temps between 400 - 480 deg. F produce less formaldehyde than cigarette smoke (comparing 15 puffs of eJuice vs. 1 low tar cigarette). The formaldehyde production increases dramatically over 550 deg. F.
Since I read this experiment (I'm not a chemist, but I took a few chem. courses in college, enough to follow this), I've started to set my AVP with temperature control to vape at 450 deg. F. I was vaping at 550. The taste and cloud temperature is still good. Speaking of taste, they actually had regular vape users sample cloud taste at the different wattage levels used in the experiment. Here is the link to that experiment:
Correlation of volatile carbonyl yields emitted by e-cigarettes with the temperature of the heating coil and the perceived sensorial quality of the generated vapours
In particular, check out the formaldehyde outputs by wattage graph (3.2), then further down see the wet coil temperature by wattage graph (3.4.2).
In order to vape safely, based on this study, I recommend using an AVP unit with Temperature Control, set between 400 - 475 deg. F. These units let you set the max coil temperature for various coil metals of known thermal coefficients of resistance (TCR). My unit, a Presa 100W by Wismec, lets me program any value of TCR from 0 - 1000. I am currently using it with a 1.2 ohm kanthal coil, and looked up the TCR of kanthal = 2. At this low TCR value, my unit resets itself occasionally, and I have to set it back from VW mode to TCR mode again. But this does not happen with higher TCR values, like 316L Stainless with TCR = 92.
Safe vaping; or live long and puff!
-Kurt
