EVALUATION OF 2 INSTRUMENTS FOR THE MEASUREMENT OF AEROSOLS

The particle size distributions and concentrations of solid and liquid aerosols were simultaneously measured with an Aerodynamic Particle Sizer (APS) and a Phase Doppler Particle Analyzer (PDPA). Three types of aerosols were characterized: mono-sized polystyrene latex (PSL) spheres, mixtures composed of mono-sized PSL spheres, and polydisperse liquid sprays. Good correlation with PSL particle sizes was obtained by both instruments with PSL spheres in the 2-10 mum range. The PDPA had difficulty in the 1 mum and smaller size range, due to the limited resolution and nonlinear behavior of the phase-diameter relationship. For polydisperse liquid sprays, instrument agreement on concentration distributions was consistently good from 1 to about 5 mum diameter. Between 5 and 10 mum, the APS progressively predicted lower concentrations. The divergence between the two instruments may be attributable both to the design of the experimental apparatus and inlet inefficiencies of the APS.