Effective Density and Complex Refractive Index Measurement of carbonaceous particles using Tandem Aerosol System

摘要

The physical properties of carbonaceous aerosol particles are often of interest but are difficult to determine from a single measurement. In this study, we used tandem aerosol measurement techniques to measure the effective physical properties, namely the effective density, porosity, and effective complex refractive index of spheroid aggregated and porous carbonaceous aerosol particles. An in-flight measurement system, composed of a differential mobility analyzer (DMA) followed by either an aerosol particle mass analyzer (APM) or a laser particle counter-pulse height analyzer (LPC-PHA), was constructed and used to examine shape-controlled and porosity-controlled carbonaceous particles produced by a spray drying process. The effective density and porosity were inferred from tandem measurements in which particles were first mobility-classified by the DMA and subsequently mass classified in the APM. The effective refractive index of the particles was inferred from tandem DMA-LPC-PHA measurements in conjunction with Mie Theory.