Nanoparticulate silica and particulate organic material from machines equipped with diesel engines in the atmosphere in both coal and non-coal mines present a significant danger to miners’ health. We are investigating ways of quantifying airborne PM<sub>2.5 </sub>α-quartz (respirable crystalline silica, RCS) and both organic carbon (OC) and elemental carbon (EC) from diesel particulate matter (DPM) that have been trapped on filters during a miner’s shift by a direct on-filter approach within a very short time after the shift is complete. The RCS is trapped on a PVC filter and its spectrum is measured by either transmission or diffuse reflection mid-infrared spectrometry followed by partial least squares regression against the value determined by the Mine Safety and Health Administration's P7 method. The determination of RCS is largely based on the quartz doublet near 800 cm<sup>-1</sup>. Besides decreased sensitivity to mineral or substrate confounders, PLS has the advantage that the analyst is not required to correct for the presence of kaolinite or background interferences related to the substrate, making the method potentially viable for automated RCS prediction in the field. For the measurement of OC, EC and total carbon, airborne DPM is trapped on a quartz filter and its reflection spectrum is measured. Since the infrared beam passes through the thin layer of DPM on the surface of the filter and the beam is scattered by the quartz filter, this is a transflection measurement. OC and EC are regressed against the corresponding values found by the NIOSH 5040 method and good correlation is found. Thus measurements of this kind can potentially lead to the replacement of time consuming and expensive measurements made days after the sample is collected by a relatively inexpensive and fast (1 minute) determination made immediately after the miner finishes a shift.

End-of-shift measurement of airborne α-quartz and diesel particulate matter by mid-infrared diffuse transflection spectrometry

255th National Meeting (2018)

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