Particle dispersion in a gas

The dispersion mechanism of particles in a gas is discussed lu the viewpoint of noncquilibrium tlaermodynamics and kinetic theory, A heuristic 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 s is defined as the ratio of the particle radius r to a multiple of the mean free path, 2, of the gas naedium. A schematic calculation demonstrates the conditions under which molecular dilKision could play a role in a realistic atmospheric pollution problem.