E-cigarette use is dramatically increasing, particularly with adolescents. While the chemical composition of e-liquids and e-vapor is well characterized, the particle size distribution and the human airways deposition patterns of e-cigarette particles are understudied and poorly understood despite their likely contribution to adverse health effects from e-cigarette usage. In this study, we examined the impacts of e-cigarette device power, e-liquid composition, and vaping topography on e-cigarette particle sizes and their deposition in human airways. In addition, we observed that particle measurement conditions (dilution ratio, temperature, and humidity) significantly affect measured e-cigarette particle sizes. E-cigarette power output significantly increased particle count median diameters (CMD) from 174 ± 13 (particles generated under 6.4 W) to 236 ± 14 nm (particles generated under 31.1 W). E-cigarette particles generated from propylene glycol-based e-liquids (CMD = 145 ± 8 nm and mass median diameter [MMD] = 3.06 ± 0.17 μm) were smaller than those generated from vegetable glycerin-based e-liquids (CMD = 182 ± 9 nm and MMD = 3.37 ± 0.21 μm). Puff volume also impacted vapor particle size: CMD and MMD were 154 ± 11 nm and 3.50 ± 0.27 μm, 163 ± 6 nm and 3.35 ± 0.24 μm, and 146 ± 12 nm and 2.95 ± 0.14 μm, respectively, for 35, 90, and 170 mL puffs. Estimated e-cigarette particle mass deposition fractions in tracheobronchial and bronchoalveolar regions were 0.504-0.541 and 0.073-0.306, respectively. Interestingly, e-cigarette particles are smaller than the particles generated from cigarette smoking but have similar human airway deposition patterns.

中文翻译：

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调查各种电子烟使用条件下的电子烟微粒排放和人道气积。

电子烟的使用正在急剧增加，尤其是在青少年中。尽管对电子液体和电子蒸汽的化学成分进行了很好的表征，但是尽管研究了电子烟颗粒可能对使用电子烟对健康产生不利影响，但对电子烟颗粒的粒径分布和人类呼吸道沉积模式的研究仍很少。在这项研究中，我们检查了电子烟设备功率，电子液体成分和雾化形貌对电子烟粒径及其在人呼吸道中的沉积的影响。此外，我们观察到颗粒测量条件（稀释比，温度和湿度）会显着影响所测量的电子烟颗粒尺寸。电子烟的功率输出从174±13显着增加了颗粒计数的中值直径（CMD）（6岁以下产生的颗粒）4 W）至236±14 nm（在31.1 W下产生的粒子）。由丙二醇基电子液体产生的电子烟颗粒（CMD = 145±8 nm，质量中值直径[MMD] = 3.06±0.17μm）小于由植物甘油基电子液体产生的电子烟颗粒（CMD = 182） ±9 nm和MMD = 3.37±0.21μm）。抽吸量还会影响蒸气粒径：CMD和MMD分别为154±11 nm和3.50±0.27μm，163±6 nm和3.35±0.24μm，以及146±12 nm和2.95±0.14μm，分别为35、90，和170毫升泡芙 气管支气管和支气管肺泡区域的估计电子烟颗粒质量沉积分数分别为0.504-0.541和0.073-0.306。有趣的是，电子烟颗粒比吸烟产生的颗粒小，但具有相似的人类气道沉积模式。