Simulation of PM_2.5 Dispersion from a Small-scale Forest Fire Based on the HYSPLIT Model

Based on the Lagrangian Hybrid Single-Particle Integrated Trajectory (HYSPLIT) model, this study quantitatively analyzed the spatiotemporal diffusion patterns of PM_2.5 emitted from a forest fire that occurred in Muli Tibetan Autonomous County, Liangshan Yi Autonomous Prefecture, Sichuan Province, using three fire emission inventories: the Global Fire Emissions Database (GFED), the Quick Fire Emissions Dataset (QFED), and the Global Fire Assimilation System (GFAS), together with meteorological data from March 29 to April 3, 2020. The simulation results were validated against Sentinel-2 satellite imagery, and simulated PM_2.5 concentrations from different inventories were compared with ground-based observations to evaluate their effectiveness and accuracy in modeling forest fire events. The results showed that the PM_2.5 diffusion patterns simulated by HYSPLIT were consistent with the smoke-affected areas visually identified in Sentinel-2 imagery, with a Sorensen index of 0.682, indicating substantial spatial agreement. The total PM_2.5 emissions varied considerably across the inventories, in the order GFED > QFED > GFAS. Ground-based PM_2.5 measurements were positively correlated with all simulated values, with correlation strength ranked as GFAS > QFED > GFED. This study demonstrates the applicability of various global fire emission inventories in small-scale forest fires and provides technical support for assessing and preventing wildfire-related pollution hazards.