Measurement of particle density using scanning mobility particle sizer and tapered element oscillating microbalance

Speaker: Mehrnaz Sarrafzadeh

Description: Density is an important property of aerosol particles. Online measurement of aerosol density is required to convert a measured aerosol size distribution into mass concentrations. Previously in our study, a density of 1 g/cm³ was assumed for aerosol particles due to the absence of aerosol density measurements for β-pinene photo-oxidation system. However, determination of the density of secondary organic aerosol (SOA) generated from β-pinene photo-oxidation would give more accurate SOA yield estimates. In addition, aerosol density is an important parameter for characterizing the particles formed. Several techniques have been developed in the past to estimate aerosol density. In this study, a Tapered Element Oscillating Microbalance (TEOM) was combined with a Scanning Mobility Particle Sizer (SMPS) to determine the density of aerosol particles. The SOA density for β-pinene photo-oxidation has been determined through the simultaneous measurement of particle volume and mass using SMPS and TEOM. In addition, the density of secondary organic matter was monitored over the course of the aging experiment to examine the effect of aging on the particle density.