Policy-driven distinct dust pollution patterns in a super-large magnesite mining area: Spatiotemporal analysis integrating satellite remote sensing and CALPUFF model

As global industrialization accelerates, increasing concern regarding health impacts on living environments has positioned air quality at the forefront of research. Dust pollution is particularly severe in open-pit mining areas, primarily due to the methods of open-pit extraction and processing. This study investigates dust dispersion driven by both anthropogenic and natural factors, employing multi-temporal aerosol optical depth (AOD) analysis, particle size distributions, and a comprehensive air quality model that incorporates plume dynamics (CALPUFF) modeling. Concentrating on Haicheng-Dashiqiao area in China, the world's largest magnesite mining area, this paper examines spatiotemporal variations in the atmospheric environment. (1) Over the past two decades, magnesite mining intensity rose from 9.17 in 2014 to 17.09 in 2024 (peaking at 28.98 in 2022). Despite this increase, AOD levels during 2014-2024 remained below those of 2001-2014, largely due to the implementation of effective pollution control policies. AOD hotspots remained concentrated within mining boundaries, consistently exceeding levels observed in surrounding non-mining regions. (2) The dust pollutants above the magnesite mining area are characterized primarily by large-sized particles, which differ significantly from those found in non-mining areas. This distinction in particle size is particularly pronounced during the summer months. (3) The PM/TSP transport fields simulated by CALPUFF align closely with the spatial patterns of satellite-derived AOD. Among the influencing factors, wind direction is the most significant, capable of transporting pollutants from the mining area up to approximately 40 km away. Furthermore, the dilution effect of spring winds on AOD is more pronounced than that observed in summer.