SCANNING ELECTRON MICROSCOPY TECHNIQUES FOR DETERMINING ATMOSPHERIC PARTICLE-SIZE DISTRIBUTION

摘要

A system to collect and classify particles in an atmospheric aerosol has been developed. A cascade-type collector with nine plates having jet sizes of 0.917 to 1.602 mm and an electrostatic precipi¬tator were used to sample the atmosphere. An SEM method for determining the particle-size distribution by sizing and counting photographed particles was developed. This method also provided for elemental analyses by x-ray fluorescence, which can detect elements of atomic number 12 and greater.nA method was also devised to determine the size of water droplets collected by this system for subsequent correlation of droplet nucleation rates with various types of particles.