Abstract An instrumental trifecta now exists for aerosol separation and classification by aerodynamic diameter (D ae), mobility diameter (D m) and mass (m) utilizing an aerodynamic aerosol classifier (AAC), differential mobility analyzer (DMA) and aerosol particle mass analyzer (APM), respectively. In principle, any combination of two measurements yields the third. These quantities also allow for the derivation of the particle effective density (ρ eff) and dynamic shape factor (χ). Measured and/or derived deviations between tandem measurements are dependent upon the configuration but are generally <10%. Notably, nonphysical values of χ (<1) and ρ eff (>bulk) were determined by the AAC-APM. Harmonization of the results requires the use of χ in the determination of m and D m from the AAC-DMA and AAC-APM requiring either a priori assumptions or determination from another method. Further errors can arise from assuming instead of measuring physical conditions – e.g., temperature and pressure affect the gas viscosity, mean free path and the Cunningham slip correction factor therefore impacting D m and D ae – but are expected to have a smaller impact than χ. Utilizing this triplet of instrumentation in combination allows for quantitative determination of χ and the particle density (ρ p). If the bulk density is known or assumed, then the packing density can be determined. The χ and ρ p were determined to be 1.10 ± 0.03 and (1.00 ± 0.02) g cm−3, respectively, for a water stabilized black carbon mimic that resembles aged (collapsed) soot in the atmosphere. Assuming ρ bulk = 1.8 g cm−3, a packing density of 0.55 ± 0.02 is obtained. Copyright © 2020 American Association for Aerosol Research

中文翻译：

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三种基本亚微米气溶胶测量的比较：质量、大小和形状

摘要 现在存在使用空气动力学气溶胶分类器 (AAC)、差分迁移率分析仪 (DMA) 和气溶胶粒子质量分析仪按空气动力学直径 (D ae)、迁移率直径 (D m) 和质量 (m) 进行气溶胶分离和分类的三重工具。 (APM)，分别。原则上，两个测量的任意组合产生第三个。这些量还允许推导粒子有效密度 (ρ eff) 和动态形状因子 (χ)。串联测量之间的测量和/或导出偏差取决于配置，但通常 <10%。值得注意的是，χ (<1) 和 ρ eff (>bulk) 的非物理值由 AAC-APM 确定。结果的协调需要使用 χ 从 AAC-DMA 和 AAC-APM 确定 m 和 D m，需要先验假设或从另一种方法确定。假设而不是测量物理条件可能会产生进一步的错误——例如，温度和压力影响气体粘度、平均自由程和坎宁安滑移校正因子，因此影响 D m 和 D ae——但预计影响比 χ 小。结合使用这三组仪器可以定量测定 χ 和粒子密度 (ρ p)。如果体积密度已知或假设，则可以确定堆积密度。χ 和 ρ p 分别确定为 1.10 ± 0.03 和 (1.00 ± 0.02) g cm-3，对于水稳定的黑碳模拟物，类似于大气中老化（塌陷）的烟灰。假设 ρbulk = 1.8 g cm-3，则获得的堆积密度为 0.55 ± 0.02。版权所有 © 2020 美国气溶胶研究协会