Cyrs W D, Boysen D A, Casuccio G, Lersch T, Peters T M
The University of Iowa, 100 Oakdale Campus, 121 IREH, Iowa City, IA 52242, USA.
ChemRisk, LLC, 25 Jessie Street, Suite 1800, San Francisco, CA 94105, USA.
J Aerosol Sci. 2010 Jul;41(7):655-664. doi: 10.1016/j.jaerosci.2010.04.007.
The surface and overall collection efficiencies of capillary pore membrane filters were measured for sub-micrometer particles. Collection efficiencies were derived from the surface loadings of particles on filters measured by scanning electron microscopy and from airborne particle concentrations measured with a scanning mobility particle sizer. Tests used filters with nominal pore diameters of 0.4 and 0.8 μm and face velocities of 3.7 and 18.4 cm/s. Surface collection efficiencies were below 100% for particles smaller than 316 nm and below 55% for particles smaller than 100 nm. Overall collection efficiencies reached as low as 45% for 70 nm particles. For nanoparticles, collection efficiencies overall were substantially higher than those to the filter surface, indicating that deposition occurs to a large extent inside the filter pores. These results underscore the need to account for surface collection efficiency when deriving airborne concentrations from microscopic analysis of nanoparticles on capillary pore membrane filters.
针对亚微米级颗粒，测量了毛细管孔膜过滤器的表面收集效率和整体收集效率。收集效率是根据通过扫描电子显微镜测量的过滤器上颗粒的表面负载量以及使用扫描迁移率颗粒粒度仪测量的空气中颗粒浓度得出的。测试使用了标称孔径为0.4和0.8μm且面速度为3.7和18.4cm/s的过滤器。对于小于316nm的颗粒，表面收集效率低于100%，对于小于100nm的颗粒，表面收集效率低于55%。对于70nm的颗粒，整体收集效率低至45%。对于纳米颗粒，总体收集效率远高于过滤器表面的收集效率，这表明沉积在很大程度上发生在过滤器孔内部。这些结果强调了在根据毛细管孔膜过滤器上纳米颗粒的微观分析得出空气中颗粒浓度时，需要考虑表面收集效率。
