Rapid Check of Cascade Impactor Cut-Sizes using a Polydisperse Challenge Aerosol Calibration Method

A method has been developed to check the 50% cut-size values of cascade impactor stages. The method involves generating a broad-size, log-normally distributed aerosol that covers the range of 50% cut-sizes for the impactor being tested. The amount of deposit on each impaction plate is analyzed and a histogram of the resulting aerosol size distribution plotted, using the amount of aerosol collected on each impaction plate and the published values for the cut-sizes of the impactor in question. If the particle size distribution indicated by the histogram does not result in a log-normal distribution, one or more of the assumed cut-sizes of the impactor are in error. The incorrect cut-sizes of the impactor can then be adjusted until the curve is log-normal, and these adjusted cut-sizes are the correct values for the impactor stages.