Research of two dust transport pollution in northern China in 2023: Perspectives from LiDAR and multi source data

Abstract

In March and April 2023, two dust events occurred in northern China, which had a huge impact on the travel and health of the public in northern China. During the two dust events (the first dust event, FD; the second dust event, SD), the peak PM₁₀ concentrations at the Handan station were 2407 μg/m³ and 829 μg/m³, respectively. According to observations from the Mie scattering LiDAR located in Handan City, during the period of FD and SD, there were differences in depolarization ratio, pollution duration, and spatial distribution. Based on multi-source data including the HYSPLIT model, MODIS sensor data, CALIPSO data, ERA5, CAMS and MERRA-2 reanalysis data, the transport process of two dust events and the causes of pollution were analyzed. The source of the FD dust air mass is twofold, On the one hand, the dust at 3000 m originates from the ground in southern Gansu, On the other hand, the dust at 1000–2000 m comes from the transport and deposition of high-altitude dust in Xinjiang. SD dust originated from deserts and Gobi regions within Mongolia. During the transboundary process, it is shown that part of FD sand dust is blown above the troposphere. When it reached Handan area, the dust above the troposphere settled. The prolonged duration of SD and the occurrence of secondary pollution were caused by calm surface winds and specific high-altitude atmospheric conditions.