| The purpose of this study was to field test the Versapor-5000® 5-μm filter and the Versapor-3000® 3-μm filter and compare atmospheric radionuclides collection efficacy. A side-by-side direct comparison was conducted, resulting in an average collection efficiency of Be-7 aerosols by the 5-μm filter of 78.9 + 12.6% of that collected by the 3-μm filter. A series-sample experiment resulted in 12.8 + 7.2% of Be-7 activity passing through the 5-μm filter and collected by the 3-μm filter. The normal laboratory method of determining Be-7 concentrations is to analyze a quarterly composite of 13 samples. Each filter was analyzed on the detector face and again on a stack on 12 unused copolymer membrane filters, where approximately 13.3 + 3.6% of the calculated Be-7 activity was lost. A 7-stage cascade impactor showed the 5-μm filter has a 100% collection efficiency of particles 1.0-μm and larger; 88.6% of the uncollected particles were <0.6-μm.
Keywords: Beryllium 7, Be-7, environmental air monitoring, DEQ |