A novel application of mobile low-cost sensors for atmospheric particulate matter monitoring in open-pit mines

Open-pit mines are an important source of atmospheric particulate matter (PM) owing to the constant earth-moving and crushing. The well-known association between high PM concentrations and adverse health effects has made the permanent control of fugitive emissions from mines a public health concern. Nevertheless, the large size of these mines renders this task difficult and expensive to perform with regulatory apparatuses; subsequently, the mining industry requires other technologies with a suitable quality/price ratio. In this study, a novel methodology for the space–time monitoring of PM concentrations in open-pit mines using mobile low-cost sensors (LCSs) is proposed. The study was carried out in the renowned mine of Riotinto for three years (2019–2021). It included a detailed calibration of the mobile LCSs that fulfilled the European/US standards. Time tendency diagrams determined the maximum PM concentrations emitted (≈1600μg PM ₁₀/m³) and also the seasonal variations. The spatial distribution also revealed the main sources of PM within the mine, which were the mining pit, mineral processing plant, spoil heap of fine materials, and main mining tracks. Finally, the integration of these data together with meteorological information allowed the discovery of the routes of escape of fugitive emissions from the mine toward nearby populations: toward W-SW, with concentrations primarily ranging between 50–100 μg PM₁₀/m³ and 20–50 μg PM_2.5/m³. The results of this research are important as mobile LCSs seem to solve the issue of fugitive emissions monitoring in mining ambiances and will aid the exploitations to become more environmentally friendly.