Particle sizing interferometer measurements of hydroscopic smokes in laboratory and field environments

A particle sizing interferometer (PSI) has been used to measure particle size distributions and mass concentration of hydroscopic smokes and fog oil in laboratory and field environments. Laboratory results show that PSI mass concentration estimates are in reasonable agreement with those obtained with a cascade impactor. Comparison of particle size distributions measured with a particle sizing interferometer and a commercially available instrument show reasonable agreement for the geometric mean size but large variations in the logarithmic standard deviations. Field tests show that geometric mean diameters are nearly independent of humidity while volumetric mean diameters tend to increase as humidity increases.