Selecting appropriate analytical methods to characterize asbestos in various media
Methods for the measurement and analysis of asbestos and other fibers in air, water, dust, and bulk materials vary by type of scenario and according to applicable laws and rules. Two surveys and a focus group were used to identify the most important information gaps in asbestos exposure assessments. The highest priority gaps were identifying analytical procedures and counting rules needed for asbestos detection; comparing the efficiency of 0.45-micron pore size filters versus 0.8-micron pore size filter media; rating the efficiency of polycarbonate versus mixed cellulose ester filters, and the need for bench-level testing of filters to evaluate fiber collection performance of these filter media. Other key responses included the need for consistency of analytical procedures and counting rules to determine suitable procedures for asbestos detection and quantitation in bulk samples, air, settled dust, and soil for field monitoring and risk analysis; need to identify underlying factors and physical dynamics that lead to aerosolization of fibers from bulk materials in various exposure pathways. The pore size of filters used in collecting fibers was identified as a key asbestos measurement uncertainty. Thus, a study is recommended to compare postpreparation asbestos fiber retention on mixed cellulose ester and polycarbonate filters.