Research on Pollution Weather Processes in Hohhot During the Winter and Spring of 2024 Based on Multi-Source Data Fusion

This study investigates typical severe pollution weather processes in Hohhot during the winter and spring of 2024, utilizing multi-source data including conventional pollutants, ground meteorological station observations, ERA5 reanalysis data, satellite imagery, and ground-based lidar measurements. The analysis reveals distinct causes for two severe pollution episodes. The February event was primarily driven by the combustion of fireworks and firecrackers, resulting in significant local particulate matter generation, with the extinction coefficient decreasing rapidly with height from the surface. In contrast, the March event was triggered by a dust storm, with integrated analysis of the HYSPLIT model and vertical observational data indicating that dust originated from southern Mongolia and the China-Mongolia border sand source regions, transported by northwest cold air to Hohhot’s upper atmosphere and subsequently settling to the ground.