Analytical solution to change in size distribution of polydisperse particles in closed chamber due to diffusion and sedimentation

Analytical solutions to the change in particle size distribution due to deposition in a closed chamber are given for different size ranges. The solutions correlate the size distribution of aerosol particles with a log-normal function. The derived solutions consist of three parameters of the log-normal size distribution. They are compared with the exact solution and the advantage of the new solutions is discussed. The monodisperse model for deposition problem is examined and is shown to cause significant errors except only in the intermediate size range where the size-dependency of the deposition rate is weak.