Development and Evaluation of a Real-Time Mid-Infrared Photoacoustic Spectrometer for Measuring Silica and Other Mineral Dust Mass Concentrations
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Authors
Taylor, Samuel Joe
Issue Date
2021
Type
Thesis
Language
Keywords
dust monitoring , infrared , mining , photoacoustics , quantum cascade laser , silica
Alternative Title
Abstract
Respirable crystalline silica (RCS) continues to be a major health concern for those employed in the mining industry. While there have been improvements in the turn-around time for filter-based measurements of RCS in mine environments, there is a distinct lack of a real-time method for quantifying it. In this study, a new real-time method using photoacoustic spectroscopy with an infrared tunable quantum cascade laser was developed. The most useful spectral region was found to be between 11 m and 13 m, and the wavelength for airborne RCS quantification was determined to be 12.495 m. It was also found that the instrument is capable of accounting for, and quantifying, kaolinite, and coal dust, which are also commonly found in coal mines. A Sensirion SPS30 low-cost air quality sensor was used to monitor particulate matter concentrations, while a TSI Aerodynamic Particle Sizer (APS) was used to record size distributions. The accuracy of this method was determined by comparing the results to the NIOSH filter-based FTIR technique for RCS mass concentration measurement. The filter-based FTIR technique, SPS30, and photoacoustic spectrometer measurements are shown to correlate strongly. The new instrument will also be useful for measuring aerosol light absorption by windblown dust in the thermal infrared atmospheric window.
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License
Creative Commons Attribution 4.0 United States