Low-temperature (< 200 °C) degradation of electronic nicotine delivery system liquids generates toxic aldehydes.

Introduction:
This text is a scientific study on the thermal degradation of electronic nicotine delivery system (ENDS) liquids, specifically propylene glycol and glycerol, at low temperatures (< 200 °C). The study uses in situ natural abundance 13C and 1h NMR to detect intact molecules from decomposition and explores the effect of oxygen availability on the degradation process. The results demonstrate that the degradation of ENDS liquids is strongly dependent on oxygen availability, both in the presence and absence of a catalyst surface.

Key Points:

* The study uses in situ natural abundance 13C and 1h NMR to detect intact molecules from decomposition of ENDS liquids.
* The degradation of ENDS liquids is strongly dependent on oxygen availability.
* The presence of oxygen enables chemical transitions not possible under inert atmospheres.
* a radical-mediated mechanism is proposed for the oxidative degradation of glycerol.
* The thermal degradation of glycerol under oxidative conditions produces toxic carbonyl-containing products.
* The second major ENDS component, propylene glycol, also degrades upon exposure to high temperatures and oxygen.
* The rate of ENDS liquids degradation may be second order with respect to oxygen.

Main Message:
The main message of this study is that the degradation of ENDS liquids is strongly dependent on oxygen availability, and the presence of oxygen enables chemical transitions not possible under inert atmospheres. The study also highlights the potential for the formation of toxic carbonyl-containing products during the thermal degradation of ENDS liquids, specifically glycerol, under oxidative conditions. additionally, the study suggests that the rate of ENDS liquids degradation may be second order with respect to oxygen, indicating that the oxygen flow into the atomizer may direct the extent to which ENDS liquids degrade. This information is crucial for understanding the safety of ENDS use and for developing appropriate regulations.

Jaegers NR, hu W, Weber TJ, hu JZ. Low-temperature (< 200 °C) degradation of electronic nicotine delivery system liquids generates toxic aldehydes. Scientific reports. 2021;11(1):7800. doi:10.1038/s41598-021-87044-x