Improved Membrane-filter Air-sampling Methods for Environmental Control

Air sampling is a useful tool for controlling, as well as for analyzing, the environment. The equipment and techniques described were designed to facilitate the collection of localized samples directly at the source of potential contamination. Routine use of membrane filters was simplified by the design of a small, inexpensive filter holder, providing advantages over commerically available units, e.g. reduced size and weight, tight sealing against any filter material without the twist-lock action which often damages filter membranes, and parts exposed to contamination are expendable. Techniques for determining sample collection rates directly from vacuum-gauge readings are discribed. A combination alpha - gamma scintillation detector assembly, designed specifically for counting membrane-filter samples, was constructed. Sample preparation techniques for use with internal proportional counters are also mentioned. (auth)