Comparison of sampling methods to measure exposure to diesel particulate matter in an underground metal mine

摘要

Diesel particulate matter (DPM) continues to be scrutinized as an adverse occupational exposure agent. Currently, the air sampling protocol approved by the U.S. Mine Safety and Health Administration (MSHA) to quantify exposure to DPM in mines designates an SKC impactor as the sample collection device and limits exposure to the total carbon faction of a DPM aerosol. Because use of this impactor requires submission of the sample to an analytical laboratory, it inherently includes a lag time before workplace exposures can be determined. Thus, mine operators who use this MSHA -approved sampling device to monitor personal DPM exposures are faced with the possibility of realizing unacceptable airborne concentrations after the exposures have occurred. In an effort to scientifically address this issue, this study performed a side-by-side sampling technique to investigate the correlation between a TSI DustTrak real-time aerosol monitor and an SKC impactor when measuring diesel particulate matter concentrations in an underground mine environment. Results of regression analysis between TWA results obtained from the two sampling devices suggest that a good correlation (R~2 = 0.91) exists when measuring submicrometer particles. Also, results from triplicate SKC impactor samples showed good precision of the National Institute of Occupational Safety and Health 5040 analytical method compared to published analytical performance criteria. In addition, SKC impactor results appear to validate MSHA's use of a 1.3 multiplier applied to elemental carbon to estimate total carbon in the presence of airborne interferences.