GENERATION OF SUBMICRON MASS VOLUME-MONODISPERSE AEROSOLS WITH A NEBULIZER-IMPACTOR-ELECTROSTATIC CLASSIFIER SYSTEM

A study was undertaken to investigate the mass size dispersion of particles classified according to their electrical mobilities. This is of primary concern in experiments that measure a concentration dependent property of the classified particles. Initially, the mass size distribution of particles produced by the 3-jet Collison, 6-jet Collison, and Misty-Ox nebulizers was measured. A 0-2 stage impactor was placed after the nebulizers and the size mass distribution was measured again. The polydisperse particle stream was then used to generate "size classified" aerosol and the mass size distribution of the equal mobility particles was calculated and measured. It was found that without an impactor in line, the aerosol stream contained a significant mass fraction of multiply charged particles. When an impactor was inserted directly after the nebulizers, the multiply charged particles were effectively removed and the particles were nearly monodisperse.