Abstract
Numerical studies of the data reduction by a cascade impactor are conducted for specific conditions. It is clearly shown that the Twomey's method is superior to the conventional method which uses a 50% cut size, when nearly monodispersed particles are measured. It is impossible to estimate the true particle size distribution by the conventional method when the geometric standard deviation of the particle size is smaller than the geometric standard deviation of partial separation efficiency.
It is possible to estimate the true particle size distribution by use of a Twomey's method, which uses a virtual stage and increases the division of the particle size, even if the geometric standard deviation of particle size distribution is less than 1.1.
