Comparison of three essential sub-micrometer aerosol measurements: Mass, size and shape
Comparison of three essential sub-micrometer aerosol measurements: Mass, size and shape
复制标题
DOI：
10.1080/02786826.2020.1763248
复制
发表时间：
2020-05
影响因子：
5.2
通讯作者：
Qi Yao;A. Asa-Awuku;C. Zangmeister;J. Radney
中科院分区：
文献类型：
--
作者：
Qi Yao;A. Asa-Awuku;C. Zangmeister;J. Radney
摘要利用气动气溶胶分级仪(AAC)、差分迁移率分析仪(DMA)和气溶胶颗粒质量分析仪(APM)分别对气溶胶进行空气动力学直径(Dae)、迁移率直径(Dm)和质量(M)的分离和分类。原则上，两种测量的任何组合都会产生第三种测量结果。这些量还允许推导出粒子有效密度(ρEff)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，但通常是批量的)由AAC-APM确定。结果的协调需要使用χ来确定AAC-DMA和AAC-APM中的m和Dm，这需要先验假设或用另一种方法确定。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修正系数，从而影响Dm和Dae--但预计影响比χ小。结合使用这三种仪器，可以定量测定χ和颗粒密度(ρp)。如果堆积密度已知或假定，则可以确定堆积密度。对于类似于大气中老化(坍塌)烟尘的水稳定黑碳模拟物，χ和ρp分别为1.1 0±0.0 3和(1.0 0±0.0 2)g cm−3。当ρ体积=1.8g cm−3时，堆积密度为0.5 5±0.0 2。版权所有(C)2020美国气溶胶研究协会
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 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