Abstract Measuring the aerosol particle size of electronic cigarettes can be particularly challenging due to the volatile and dynamic nature of these aerosols. In particular, electronic cigarette aerosol particle size measurements may be convoluted by evaporation due to the high dilution ratios and coagulation when there are long residence times between sampling and measurement. To address these measurement issues, we have developed a particle size measurement system using a low flow cascade impactor with a sampling system that is capable of generating a puff on an e-cigarette and directly introducing the aerosol into the inlet flow of the impactor. The system has been used to investigate factors that may affect the aerosol size distribution, including puffing conditions, carrier composition and device construction. It was found that decreasing the puff flow rate from 2 to 0.5 L/min at a constant puff duration of 5 s, the mass median aerodynamic diameter (MMAD) of the aerosol size distribution increased from 0.5 to 1.1 µm. Increasing the mass delivery from 0.67 to 6 mg/5 s puff also resulted in increasing MMAD from 0.48 to 0.87 µm. Furthermore, the addition of a small amount of glycerin (1% by weight) to a propylene glycol based flavor formulation caused a decrease in the MMAD, while the other factors studied did not have a significant effect on the MMAD. Copyright © 2020 American Association for Aerosol Research

中文翻译：

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用级联撞击器测量电子烟气溶胶的粒径

摘要 由于这些气溶胶的挥发性和动态特性，测量电子烟的气溶胶粒径尤其具有挑战性。特别是，电子烟气溶胶粒径测量可能会因高稀释率和凝结而导致蒸发，因为采样和测量之间存在较长的停留时间。为了解决这些测量问题，我们开发了一种使用低流量级联撞击器和采样系统的粒度测量系统，该系统能够在电子烟上产生一口烟，并将气溶胶直接引入撞击器的入口流中。该系统已用于研究可能影响气溶胶粒径分布的因素，包括膨化条件、载体成分和装置结构。发现在 5 秒的恒定抽吸持续时间下将抽吸流速从 2 L/min 降低到 0.5 L/min，气溶胶尺寸分布的质量中值空气动力学直径 (MMAD) 从 0.5 µm 增加到 1.1 µm。将质量输送从 0.67 增加到 6 mg/5 s 抽吸也导致 MMAD 从 0.48 增加到 0.87 µm。此外，向基于丙二醇的调味剂配方中加入少量甘油（1% 重量）会导致 MMAD 降低，而研究的其他因素对 MMAD 没有显着影响。版权所有 © 2020 美国气溶胶研究协会 67 到 6 毫克/5 秒的抽吸也导致 MMAD 从 0.48 增加到 0.87 微米。此外，向基于丙二醇的调味剂配方中加入少量甘油（1% 重量）会导致 MMAD 降低，而研究的其他因素对 MMAD 没有显着影响。版权所有 © 2020 美国气溶胶研究协会 67 到 6 毫克/5 秒的抽吸也导致 MMAD 从 0.48 增加到 0.87 微米。此外，向基于丙二醇的调味剂配方中加入少量甘油（1% 重量）会导致 MMAD 降低，而研究的其他因素对 MMAD 没有显着影响。版权所有 © 2020 美国气溶胶研究协会