A second control study was performed to validate the feasibility of relatively lower vaping temperatures leading to the formation of ketene. Each of the dab platform experiments described above was initially run at 378 °C, in keeping with our prior studies. During the course of this study, we collaborated on a peer-reviewed systematic survey and analysis of user-preferred THC-acetate dabbing temperatures. Temperatures ≥ 378 °C were preferred by 8 % of respondents. For relevance to a wider range of users we thus investigated and found readily detectable ( 1 H NMR, Figure ) levels of ketene as N-benzylacetamide equivalents when the aerosolization was performed at 287 °C, a temperature setting at or above which > To investigate the potential role of oxygen in ketene formation, we dabbed ethyl acetate (EtOAc, Figure ) and geranyl acetate (Figure ) at 378 °C in a glove bag in ambient air (~21% O 2 ) conditions and also under N 2 (<0.1% O 2 ). EtOAc or geranyl acetate (500 ul) were used in these experiments since they are liquids, and thus more amenable to glove bag conditions. The transformation of EtOAc to ketene had been simulated by others, with vaping temperatures > 840 ⁰C needed to afford enough ketene to be introduced into a user's lungs. However, Figure shows that, at 378 ⁰C, N-benzylacetamide derived from dabbing EtOAc is ~ 10-fold higher under ambient aerobic (0.025 mg) versus reduced O 2 conditions (0.0025 mg). Importantly, EtOAc is a prevalent flavorant molecule used in tobacco e-cigarettes. It was observed to be the fifth most frequently occurring flavor chemical in a study of 277 e-liquid products. Geranyl acetate (Figure ) exhibited analogous behavior, with ~ 20 fold more ketene generated under ambient aerobic conditions.