Real-Time Separation and Detailed Characterization of Aspherical Submicron Aerosols

SCHUYLER LOCKWOOD, David Bell, Alla Zelenyuk, Pacific Northwest National Laboratory

     Abstract Number: 764
     Working Group: Instrumentation and Methods

Abstract
Particle shape plays an important role in determining particle properties and behavior. We have developed several different approaches that make it possible to identify in real-time the presence of particles of different shapes, separate them based on their shape for in-situ and offline analysis, and characterize their chemical and physical properties. These approaches rely on the simultaneous sequential characterization of aerosol particles by two or three instruments that are traditionally used for characterization of submicron aerosol particles.

Here we employ different combinations of instruments (1) Centrifugal Particle Mass Analyzer (CPMA), used to measure particle mass distributions or select particles with narrow distribution of masses; (2) Scanning Mobility Particle Sizer (SMPS) or a differential mobility analyzer (DMA), used to measure particle mobility size distributions or select particles with narrow distribution of mobility diameters; (3) Aerodynamic Aerosol Classifier (AAC), used to measure particle aerodynamic size distributions or select particles with narrow distribution of aerodynamic diameters; and (4) single particle mass spectrometer, miniSPLAT, used to characterize vacuum aerodynamic diameters and composition of individual aerosol particles.

We will present the results of a recent study, in which these approaches were successfully applied for detailed characterization of spherical particles with different composition and densities, and aspherical particles with different compositions, shapes, and morphologies, including fractal and compact agglomerates of nanoparticles.