Tracking prevailing dust aerosol over the air pollution in central China with integrated satellite and ground observations

Abstract

Besides intense dust storms, downstream transport of dust particles in the extensive deserts of East Asia have been rarely concerned. In this study, we present a comprehensive insight into sources, transport process, and potential influence of the prevalent dust particles in central China during October 2020 based on integrated satellite and ground observations. Although dust events are usually considered concentrated in spring, satellite observations show that dust sources are active during fall. Thick dust layers with high uplifted altitudes at ~5 km are found in their downstream path, which can be carried to northern China and even the Sichuan Basin by predominant northwestern winds at 700 hPa. Despite a lack of air masses directly from active dust sources, dust plumes from both Taklimakan Desert and Gobi deserts can be blown to central China in their transport path or when they have arrived over northern and eastern China. Unlike dust storms with strong winds cleaning local atmospheric pollutants, these floating dust plumes tend to suspend over the air pollution near surface. In particular, the slow dust-pollution mixing process in central China can last for as long as ~3–4 days due largely to the common temperature inversion in fall. Despite a dominant contribution (>50%) in particle pollution, these dust transport with much smaller scales than dust storms can be unnoticeable. Our results suggest that more attention should be paid to the role of these unnoticeable but frequent dust plumes in regional atmospheric environment and climate effects.