PARTICLE DISPERSION IN A GAS

The dispersion mechanism of particles in a gas is discussed from the v iewpoint of nonequilibrium thermodynamics and kinetic theory. A heuris tic equation, based on the quasi-lorentz model developed by Mason and other workers, for the particle velocity in the presence of a gradient of pressure and temperature is proposed for all values of a parameter s, where a is defined as the ratio of the particle radius r to a mult iple of the mean free path, lambda, of the gas medium. A schematic cal culation demonstrates the conditions under which molecular diffusion c ould play a role in a realistic atmospheric pollution problem.