Carbon monoxide concentration in mainstream E-cigarette emissions measured with diode laser spectroscopy
Abstract: The e-fluid heated in electronic cigarettes (e-cigarettes) is largely composed of organic compounds, specifically propylene glycol, vegetable glycerin and flavouring compounds. When heated, as it is in an e-cigarette, the chemical species in this fluid have the potential to oxidise into carbon monoxide (CO) and other species. Using diode laser spectroscopy, the concentration of CO in e-cigarette mainstream effluent as a function of e-cigarette power and flavour was measured. Carbon monoxide concentration was found to be a direct function of the power of the resistive heating. At the highest powers testable using commercial e-cigarette components, the maximum CO concentration measured was over 180 ppm. The flavouring compounds in the e-fluid also had an effect on the concentration of carbon monoxide present in the effluent.
Study used a Wismec Reuleaux RX2 20700 TC, Box Mod, and an aspire Cleito tank with a 0.2 ohm coil (Manufacturers recommended operating parameters: 55W – 70W). Authors then operated the coil up to the full 200W of power deliverable by the power supply.
Flow rates (0.85 L/min) and puff duration (nominal 4 seconds) would equate to a puff volume of 0.0566~ L. This volume would not be reflective of a direct to lung inhale pattern which would be closer to a tidal inhalation volume of 0.25 L (1/2 of tidal volume over all where average tidal volume is 0.5 L)
Figure 2 in the study (isolated behind pay wall) does not provide the raw data values for the key points marked on the graph, however the first signs of elevating CO levels is either at, or above manufacturer recommended operating power levels, and would be impacted by the reduced air volumes in the study compared to volumes that would be expected if the tank was being used by a human being as a Direct To Lung (DTL) delivery system.
Tobacco Control (BMJ)
Rileigh Casebolt, S Jewel Cook, Ana Islas, Alyssa Brown, Karen Castle, Dabrina D Dutcher
Casebolt R, Cook SJ, Islas A, et al. Carbon monoxide concentration in mainstream E-cigarette emissions measured with diode laser spectroscopy. Tobacco Control Published Online First: 25 November 2019. doi: 10.1136/tobaccocontrol-2019-055078