Filter Pack Technique For Classifying Radioactive Aerosols By Particle Size

Study of the efficiency of filters for the retention of natural airborne radioactive aerosols has shown that the paricles with which the radioactivity of the short-lived radon daughters is associated have greater ability to penetrate the variousfilter media than has the fission product debris in the atmosphere; therefore the former is associated with aerosols of smaller size. A preliminary evaluation of the techniques of employing packs of filters of different retentivity characteristics to determine the particle size and/or particle size distribution of radioactive aerosols has been made which indicates the feasibility of the method. It is recommended that a series of measurements be undertaken to determine the relative particle size distribution of RaB+C as a function of time, season and weather, and the size ditribution of fission products as a function of the above parameters and the source of the debris. (Author).