Development and validation of an automatic filter-replacement coal dust concentration detector based on light extinction

Abstract Particulate matter in the workplace has a significant impact on environmental pollution and the health of workers. Accurate real-time monitoring of particulate matter concentration is essential for preventing and controlling environmental pollution. This study presents the development and performance evaluation of a coal dust mass concentration monitoring device based on the light extinction principle, integrated with an automatic filter replacement system. A detection model was established to convert light extinction signals into mass concentration values by applying the Lambert–Beer law combined with linear regression analysis. To mitigate the contamination of optical components caused by dust particles, an automatic filter tape mechanism was designed, inspired by the BAM-1020 β -ray particulate monitor, enabling long-term continuous monitoring. Through experimental comparisons, an infrared LED light source with a 30° emission angle and an SPS0606 silicon photodiode were selected as the optimal optical detection components. Additionally, using experimental data from three representative coal dust types—lignite, bituminous coal, and anthracite—a light extinction-based detection model was constructed, demonstrating strong stability and adaptability across different coal types and particle sizes. Finally, a comparative experiment was conducted between the prototype and a commercial PMS1600 light scattering dust sensor, with filter weighing method serving as the reference standard. Results show that the prototype achieved a relative error within ±15% under low concentration conditions (<25 mg m −3 ) and within ±10% under high concentration conditions (>25 mg m −3 ), meeting the accuracy requirements for practical applications.