| Particulate matter (PM) is a common occupational and ambient exposure concern. Some examples of occupational sources of PM include; stone crushing, burning wood, grinding, cutting, drilling, and emissions from cars, trucks, buses, and factories. Respirable pm, also commonly called respirable dust, is of particular concern because it is small enough to reach the gas-exchange region of the lungs. There are several methods used to assess occupational and ambient exposures to respirable pm. The most common of these methods is to use a cyclone sampler to collect PM onto a filter, which is then analyzed gravimetrically. Accurate assessment and measurement of PM exposure requires accurate pump-calibration procedures.;This study evaluates the coal mine respirable dust sampling calibration methods published by the U.S. Mine Safety and Health Administration (MSHA) to determine if there are significant differences in flow rates achieved with the various methods. A Dorr Oliver cyclone attached to a 37 mm PVC filter was connected to an MSA Escort Elf pump. Three trials were conducted in which two of MSHA's calibration methods (Jar and Tape Method) were compared. Calibration flow rates were measured using a Gilibrator calibration device.;A one-way analysis of variance (ANOVA) with a 95% confidence interval was performed on combined data from all three trials to determine if there were differences or correlations between the flow rates of the calibration methods. The flow rates of all three trials (n = 240) were compared against the five calibration types that were performed in each trial (jar, duct, electrical, clay, and masking tape). When comparing flow rate and calibration type, a significant difference was found (p = 0.000). A Tukey comparison of the data also showed that some of the types of tape had significantly different flow rates. |
