Tran Lillian N, Chiu Elizabeth Y, Hunsaker Haylee C, Wu Kuan-Chen, Poulin Brett A, Madl Amy K, Pinkerton Kent E, Nguyen Tran B
Department of Environmental Toxicology, University of California, Davis, Davis, California 95616, United States.
Department of Chemistry, University of California, Davis, Davis, California 95616, United States.
Chem Res Toxicol. 2023 Sep 12;36(10):1599-610. doi: 10.1021/acs.chemrestox.3c00172.
Aerosol formation and production yields from 11 carbonyls (carbonyl concentration per aerosol mass unit) were investigated (1) from a fourth-generation (4th gen) e-cigarette device at different coil resistances and coil age (0-5000 puffs) using unflavored e-liquid with 2% benzoic acid nicotine salt, (2) between a sub-ohm third-generation (3rd gen) tank mod at 0.12 Ω and a 4th gen pod at 1.2 Ω using e-liquid with nicotine salt, together with nicotine yield, and (3) from 3rd gen coils of different metals (stainless steel, kanthal, nichrome) using e-liquid with freebase nicotine. Coil resistance had an inverse relationship with coil temperature, and coil temperature was directly proportional to aerosol mass formation. Trends in carbonyl yields depended on carbonyl formation mechanisms. Carbonyls produced primarily from thermal degradation chemistry (e.g., formaldehyde, acetaldehyde, acrolein, propionaldehyde) increased per aerosol mass with higher coil resistances, despite lower coil temperature. Carbonyls produced primarily from chemistry initiated by reactive oxygen species (ROS) (e.g., hydroxyacetone, dihydroxyacetone, methylglyoxal, glycolaldehyde, lactaldehyde) showed the opposite trend. Coil age did not alter coil temperature nor aerosol mass formation but had a significant effect on carbonyl formation. Thermal carbonyls were formed optimally at 500 puffs in our study and then declined to a baseline, whereas ROS-derived carbonyls showed a slow rise to a maximum trend with coil aging. The 3rd gen versus 4th gen device comparison mirrored the trends in coil resistance. Nicotine yields per aerosol mass were consistent between 3rd and 4th gen devices. Coil material did not significantly alter aerosol formation nor carbonyl yield when adjusted for wattage. This work shows that sub-ohm coils may not necessarily produce higher carbonyl yields even when they produce more aerosol mass. Furthermore, carbonyl formation is dynamic and not generalizable during the coil's lifetime. Finally, studies that compare data across different e-cigarette devices, coil age, and coil anatomy should account for the aerosol chemistry trends that depend on these parameters.
研究了11种羰基化合物（每气溶胶质量单位的羰基浓度）的气溶胶形成和产率：(1) 使用含2%苯甲酸尼古丁盐的无味电子烟液，对第四代（4代）电子烟装置在不同线圈电阻和线圈使用时长（0 - 5000口抽吸）下进行研究；(2) 使用含尼古丁盐的电子烟液，对比0.12Ω的亚欧姆第三代（3代）储油雾化器和1.2Ω的4代烟弹，同时研究尼古丁产率；(3) 使用含游离碱尼古丁的电子烟液，对不同金属（不锈钢、镍铬铁合金、镍铬合金）的3代线圈进行研究。线圈电阻与线圈温度呈反比关系，且线圈温度与气溶胶质量形成成正比。羰基产率趋势取决于羰基形成机制。主要由热降解化学过程产生的羰基化合物（如甲醛、乙醛、丙烯醛、丙醛），尽管线圈温度较低，但随着线圈电阻升高，每气溶胶质量中的含量增加。主要由活性氧（ROS）引发的化学反应产生的羰基化合物（如羟基丙酮、二羟基丙酮、甲基乙二醛、乙醇醛、乳醛）则呈现相反趋势。线圈使用时长既未改变线圈温度，也未改变气溶胶质量形成，但对羰基形成有显著影响。在我们的研究中，热羰基化合物在500口抽吸时形成最佳，随后降至基线水平，而ROS衍生的羰基化合物则随着线圈老化呈现缓慢上升至最大值的趋势。3代与4代装置的比较反映了线圈电阻的趋势。3代和4代装置每气溶胶质量的尼古丁产率一致。在调整功率后，线圈材料对气溶胶形成和羰基产率没有显著影响。这项研究表明，即使亚欧姆线圈产生更多的气溶胶质量，它们不一定会产生更高的羰基产率。此外，羰基形成是动态的，在整个线圈使用寿命期间并不具有普遍性。最后，比较不同电子烟装置、线圈使用时长和线圈结构数据的研究应考虑到取决于这些参数的气溶胶化学趋势。
