Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada.
Environ Sci Technol. 2020 Nov 17;54(22):14215-14223. doi: 10.1021/acs.est.0c03728. Epub 2020 Nov 4.
Thirdhand smoke (THS) deposits to surfaces following smoking events and is a source of chemical exposure to humans. However, the evolution of THS in indoor environments is not well understood. Cannabis THS is a chemically distinct and prevalent form of THS, which has not been studied. The heterogeneous reaction of Δ-tetrahydrocannabinol (THC), a major component of cannabis smoke, with ozone was examined as a pure compound and within cannabis smoke. Oxidative decay via ozonolysis and product formation were monitored by liquid chromatography-tandem mass spectrometry. Epoxide, dicarbonyl, and secondary ozonide THC reaction products were detected from both pure THC and cannabis experiments, with the product ratios dependent on relative humidity. The observed reaction kinetics for loss of THC on glass and cotton surfaces are consistent with a relatively short loss lifetime, which will be strongly dependent on the film thickness, ozone mixing ratio, and ozone reactivity of the surface substrate. The low volatility of THC and its oxidation products suggest that their contributions to thirdhand cannabis smoke will be less significant than the role that nicotine plays in thirdhand tobacco smoke.
三手烟（THS）是吸烟事件后在表面沉积的物质，是人类接触化学物质的来源之一。然而，室内环境中 THS 的演变过程还不是很清楚。大麻三手烟是一种化学性质独特且普遍存在的三手烟形式，但尚未得到研究。我们研究了大麻烟雾主要成分 Δ-四氢大麻酚（THC）与臭氧的不均匀反应，既作为纯化合物，也在大麻烟雾中进行研究。通过液相色谱-串联质谱监测了臭氧分解和产物形成过程中的氧化衰减。从纯 THC 和大麻实验中都检测到了 THC 的环氧化物、二羰基和次级臭氧化物反应产物，其产物比取决于相对湿度。在玻璃和棉表面观察到的 THC 损失反应动力学与相对较短的损失寿命一致，这将强烈依赖于薄膜厚度、臭氧混合比和表面底物的臭氧反应性。THC 及其氧化产物的低挥发性表明，它们对三手大麻烟雾的贡献将不如尼古丁在三手烟草烟雾中所起的作用重要。
