MEASUREMENT OF RESUSPENDED AEROSOL IN THE CHERNOBYL AREA .1. DISCUSSION OF INSTRUMENTATION AND ESTIMATION OF MEASUREMENT UNCERTAINTY

Results of measurements of the resuspended radioactive aerosols in the Chernobyl area are presented which were obtained soon after the Chern obyl reactor accident and in a European project in 1992-1993. The meas urements were carried out with the intention of obtaining a data base for dose assessment of resuspended radioactive particles. Potential si gnificant dose contributions may result from inhalation and secondary contamination due to resuspended radionuclides. In this first article of a series of three papers, the instrumentation and the measurement u ncertainties are discussed. An effort was made to sample quantitativel y giant aerosol particles (particles larger than 10 mu m aerodynamic d iameter) as well. The comparison of the samplers shows, in general, an agreement of concentration measurements of Cs-137 and Be-7 within a f actor of two. One sampler was identified with larger discrepancies and needs additional investigation of its sampling characteristics; for a nother device, the recalibration of the analysing system is recommende d. Ordinary integrating samplers have a loss of about 30% in Cs-137 ac tivity compared to an isokinetic sampler collecting giant particles as well. The mean ratio of Cs activity concentration between an instrume nt sampling only particles larger than 10 mu m and an ordinary integra ting sampler is 0.39 +/- 0.15 during anthropogenic-enhanced resuspensi on. These findings demonstrate the significant contribution of giant p articles to resuspended airborne radioactivity. The results of this st udy concerning integral measurements during wind-driven resuspension p roved to be in good agreement with previously published data on resusp ension.