ABSTRACT
The physical behavior of a particle is determined largely by its size. The settling velocity of the particle, light scattered from the particle, and adhesion of a particle to a surface are examples of particle-size-dependent physical properties important in contamination control. It follows that selection of the measuring instruments, cleaning techniques, and understanding detrimental effects from particles are critically dependent on the particle size. A particle size distribution is the concentration of particles as a function of particle size. The normal distribution results from the action of many random additive and subtractive effects on an initially homogeneous population. In particle statistics, normal distributions are only found in cases of a vary narrow size range. Examples are nearly monodisperse calibration aerosols. Distribution models allow to simplify the way we look at data and include normal, log-normal, and power law distributions.
