We will describe the use of a newly developed system to measure individual particles compositions, mass, mobility, and vacuum aerodynamic diameters. In this system, an aerosol particle mass analyzer (APM) is used to classify particles with a narrow distribution of masses that are further classified with differential mobility analyzer (DMA) to generate an aerosol population with a narrow distribution of shapes. The vacuum aerodynamic size distributions of these particles are measured with single particle mass spectrometer, SPLAT-II. The combined APM/DMA/SPLAT-II system provides information to determine particle density, fractal dimension, and dynamic shape factors in the transition (?t) and in the free molecular (?v) regimes to establish a direct relation between the two. We use this approach to measure the density of spherical particles, and determine dynamic shape factors of glass bead dimers, (NH4)2SO4, and NaCl particles. We demonstrate that (NH4)2SO4 and NaCl particles are present in a distribution of shapes.

Simultaneous
characterization of individual particles compositions, mass, mobility, vacuum
aerodynamic diameters, and dynamic shape factors in the transition and free
molecular regimes

242nd National Meeting (2011)

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Simultaneous characterization of individual particles compositions, mass, mobility, vacuum aerodynamic diameters, and dynamic shape factors in the transition and free molecular regimes