Electronic Cigarettes Part IX Vapor Analysis – What does all this mean?26 Jun 2015
Sorry for the two month blog delay, but by now you know we were utilizing multi-bed thermal desorption (TD) tubes to collect and analyze electronic cigarette vapor (see our last blog here). You also know that we found some interesting volatile organic compounds (VOCs) like formaldehyde, acetaldehyde, acrolein, xylenes, as well as siloxanes in electronic cigarette vapor. It is important to stress that the hazardous air pollutants (HAPS) formaldehyde, acetaldehyde, and acrolein were found in the vapor of four commercially available 1st generation e-cigarettes; however, these compounds were not present in the solutions. It is also important to note that these compounds were not found in the background air. Lastly, I must emphasize that our peers like Goniewicz et al. and Kosmider et al. have made the same observations for e-cig vapor. So we are just one of a few of the messengers (remember that when you are looking to shoot the messenger).
Up until now we have only talked about the presence of carcinogenic and toxic VOCs being identified in electronic cigarette vapor. However, we have not put any of this into a context, which may help make all these blogs more relevant to human health. To expound upon this further, it is important for me to acknowledge that I am more than likely breathing high pptv to low ppbv levels of formaldehyde, benzene, and other toxic VOCs as I type this blog. Therefore it is unjust to merely point out that we identified toxic VOCs in e-cig vapor.
So without further ado… remember that the HAP acrolein was not found in electronic cigarette solutions. In addition, acrolein was not found in the background air. However, acrolein was found in the vapor from all four of the e-cigarettes evaluated in our work. The acrolein concentrations ranged from 1.5 to 6.7 ppmv per 40 mL puff (0.003 to 0.015 µg/mL), which is comparable to the 0.004 µg/mL Goniewicz et al. reported. To put these concentrations into perspective, these levels exceeded the National Institute of Occupational Safety and Health (NIOSH) short-term exposure limit (STEL) of 350 ppbv. It is important to note that although we were not calibrated at the time for formaldehyde and acetaldehyde, the vapor concentrations for these two compounds appeared to be approximately the same as the acrolein concentrations observed. Again, the observation is consistent with what Goniewicz et al. reported.
It then becomes clear to me why end users experience what is often referred to as “throat hit.” These three carbonyls are well known mucous membrane (including eyes, nose, and respiratory tract) irritants, and inhaling ppmv levels (as those observed in the current study and our peers’ studies as well) of these three carbonyls would surely illicit said sensation. And we have not even begun to talk about the other identified and numerous unidentified VOCs we observed.
But as the title begs… WHAT DOES ALL THIS MEAN? Well obviously this means we cannot tell you electronic cigarettes contain no toxic chemicals. In fact, some e-cig manufacturers are already putting out disclaimers about their products.
M.L. Goniewicz, J. Knysak, M. Gawron, L. Kosmider, A. Sobczak, J. Kurek, A. Prokopowicz, M. Jablonska-Czapla, C. Rosik-Dulewska, C. Havel, P. Jacob III, N. Benowitz, Levels of selected carcinogens and toxicants in vapour from electronic cigarettes, Tob Control 23 (2014) 133.
Kosmider, A. Sobczak, M. Fik, J. Knysak, M. Zaciera, J. Kurek, M.L., Goniewicz,Carbonyl compounds in electronic cigarette vapors: effects of nicotine solvent and battery output voltage,Nicotine Tob Res 16 (2014) 1319.