The terminal velocity and size of airborne dust particles

Abstract

An instrument for sampling airborne particles is briefly described, in which the particles are classified according to their terminal velocities and deposited on a glass plate in a continuously graded sample. It can be employed to determine: (i) the Stokes' diameter-frequency distribution; (ii) the variation of mean projected diameter for a constant value of Stokes' diameter, and the variation of the Stokes' diameter for a constant value of mean projected diameter; (iii) the mean weight of particles of given Stokes' diameter.