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The new American Society for Testing and Materials (ASTM) Standard Test Method D5755 for Microvacuum Sampling and Indirect Analysis of Dust by Transmission Electron Microscopy for Asbestos Structure Number Concentrations is a useful approach for determining the presence or absence of asbestos. Its prediction of past or potential future airborne exposures is also helpful in ascertaining asbestos presence or absence. With the ASTM protocol, the count method can be examined by laboratories in terms of its usefulness in assessing building contamination and predicting airborne exposures.

Comments on several studies on diabetes. Selective screening for gestational diabetes in Chinese women; Effect of cigarette smoking on glycemic control in diabetes; Beneficial effect of diabetes on acute intermittent porphyria.

Discusses the views of members of the American Society for Testing and Materials on the study `Effect of indirect sample preparation procedures on the apparent concentration of asbestos in settled dusts.' Accusations in relation to misleading information; Discussion of the experiments described; Effects of asbestos in airborne exposure.

To measure airborne asbestos and other fibers, an air sample must represent the actual number and size of fibers. Typically, mixed cellulose ester (MCE, 0.45 or 0.8 microm pore size) and, to a much lesser extent, capillary-pore polycarbonate (PC, 0.4 microm pore size) membrane filters are used to collect airborne asbestos for count measurement and fiber size analysis. In this research study, chrysotile asbestos (fibers both shorter and longer than 5 microm) were generated in an aerosol chamber and sampled by 25 mm diameter MCE filter media to compare the fiber retention efficiency of 0.45 microm pore size filters vs. 0.8 microm pore size filter media. In addition, the effect of plasma etching times on fiber densities was evaluated. This study demonstrated a significant difference in fiber retention efficiency between 0.45 microm and 0.8 microm pore size MCE filters for asbestos aerosols (structures longer than or equal to 0.5 microm length). The fiber retention efficiency of a 0.45 microm pore size MCE filter is statistically significantly higher than that of the 0.8 microm pore size MCE filter. However, for asbestos structures longer than 5 microm, there is no statistically significant difference between the fiber retention efficiencies of the 0.45 microm and 0.8 microm pore size MCE filters. The mean density of asbestos fibers (longer than or equal to 0.5 microm) increased with etching time. Doubling the etching time increased the asbestos filter loading in this study by an average of 13%. The amount of plasma etching time had no effect on the filter loading for fibers longer than 5 microm. Many asbestos exposure risk models attribute health effects to fibers longer than 5 microm. In these models, both the 0.45 microm and 0.8 microm pore size MCE filter can produce suitable estimates of the airborne asbestos concentrations. However, some models suggest a more significant role for asbestos fibers shorter than 5 microm. Exposure monitoring for these models should consider only the 0.45 microm pore size MCE filters as recommended by the U.S. Environmental Protection Agency Asbestos Hazard Emergency Response Act (AHERA) protocol and other methods.