Longer dust events over Northwest China from 2015 to 2022

Dust events show volatile characteristics in the Northwest warming and wetting trend under global warming. Previous studies yet pay little attention to the specific characteristic of the duration of dust events. We present herein our findings on the changes of dust event duration (DED) and its influencing factors over Northwest China based on hourly resolution air quality observations. We find that the duration of dust events over Northwest China increased by ~25% from 2015 to 2022. This increase is mainly attributed to moderate and heavy dust events, especially for regions close to dust sources, where moderate dust event frequency decreases significantly. Correlation analyses with meteorological factors reveal that increased lower tropospheric stability (LTS) is significantly associated with increased DED, implying that greater stability hinders dust dry deposition and transport processes, thereby promoting a longer residence time. Additionally, the DED in dust source regions negatively correlates with precipitation frequency (less wet deposition), while in non-dust source regions, it positively correlates with dust transport. It suggests that the factors enhancing DED vary with distance from dust sources. These findings will help elucidate dust event characteristics (especially the duration) and their changes over Northwest China, and will inform local dust management.