The use of transmission electron microscopy with scanning mobility particle size spectrometry for an enhanced understanding of the physical characteristics of aerosol particles generated with a flow tube reactor
The use of transmission electron microscopy with scanning mobility particle size spectrometry for an enhanced understanding of the physical characteristics of aerosol particles generated with a flow tube reactor
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DOI：
10.1080/02786826.2023.2173999
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发表时间：
2023-01
影响因子：
5.2
通讯作者：
Emma C. Tackman;Devon N. Higgins;Devan E. Kerecman;Emily-Jean E. Ott;M. Johnston;M. Freedman
中科院分区：
文献类型：
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作者：
Emma C. Tackman;Devon N. Higgins;Devan E. Kerecman;Emily-Jean E. Ott;M. Johnston;M. Freedman
摘要气溶胶粒子分布于大气中，其形态特征和化学组成有很大的差异。识别和表征这些粒子属性是提高我们对大气化学的理解的重要一步。存在许多方法来测量艾特肯模式粒子的大小和传播，但很少有研究严格比较在这一领域的方法之间产生的结果。在这里，我们比较了两种方法来评估气溶胶颗粒-扫描迁移率粒径谱（SMPS）和透射电子显微镜（TEM）。在流动管式反应器中制备了由盐晶种和α-蒎烯二次有机物包覆晶种组成的Aitken模式粒子。使用两种技术分析相同的颗粒群，以便于直接比较。对于撞击到碳和Si TEM基底上的硫酸铵颗粒，当与悬浮电迁移率直径相比时，直径增加了+0%至+30%，对于单组分系统来说是出乎意料的宽范围。涂层颗粒具有不可预测的直径差异，当与相应的SMPS电迁移率直径相比时，有时在较大的尺寸下进行评估，有时在较小的尺寸下进行评估，从-34%到+60%。虽然所有颗粒的形状通常是圆形的，但在涂覆的样品中也观察到颗粒形态的变化。0%和98%之间的颗粒表现出明显的相分离，这表明更多的人口水平的多样性比预期的这些颗粒生成过程。表征TEM和SMPS结果之间的差异更好地阐明了基板的作用，并显示从不同仪器获得的粒度分布的不等效性。版权所有© 2023美国气溶胶研究协会
Abstract Aerosol particles are found throughout the atmosphere with considerable variety in morphological characteristics and chemical composition. Identifying and characterizing these particle attributes is a significant step toward improving our understanding of atmospheric chemistry. Many methods exist for measuring the size and spreading of Aitken mode particles, but there are few studies rigorously comparing the results generated between approaches in this field. Here, we compare two methods for assessing aerosol particles – scanning mobility particle size spectrometry (SMPS) and transmission electron microscopy (TEM). Aitken mode particles consisting of salt seed particles and seed particles coated with α-pinene secondary organic material were produced in a flow tube reactor. The same populations of particles were analyzed using both techniques to facilitate direct comparison. For ammonium sulfate particles impacted onto carbon and Si TEM substrates, diameters increased by +0% to +30% when compared to the suspended electrical mobility diameters, an unexpectedly wide range for a single component system. Coated particles had unpredictable diameter differences, sometimes evaluated at larger and sometimes smaller sizes after impaction when compared to the corresponding SMPS electrical mobility diameter, from −34% to +60%. While all particles were generally round in shape, variation in particle morphology was also observed in coated samples. Between 0% and 98% of particles displayed obvious phase separation suggesting more population-level diversity than expected from these particle generation processes. Characterizing the differences between TEM and SMPS results better elucidates the role of a substrate where present and shows nonequivalence in particle size distributions obtained from different instruments. Copyright © 2023 American Association for Aerosol Research GRAPHICAL ABSTRACT