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).

From symposium on environmentl surveillance around nuclear installation; Warsaw, Poland (5 Nov 1973). A new concept in the sizing of radioactive or nonradioactive airborne Particulate matter has been assembled into a mobile field unit and is being applied to present environmental and health physics particle size information needs. The glow-discharge perturbat ion method economically generates particle size data which can be directly accumulated and spectrometrically analyzed by a multichannel analyzer. The basics of the glow- discharge technique are touched upon and compared to other instrumentation presently available in this province of the environmental sciences. The physical description, operational characteristics and current uses of the apparatus are detailed, along with importnt design and operational parameters. Particle size distribution data and analysis techniques illustrating the utility of this system are presented. (auth).