Emissions of biological soil crust particulate matter and its proportion in total wind erosion

Abstract Areas subjected to frequent winds show severe farmland degradation and air pollution caused by wind erosion and particulate matter emissions. Biological soil crust (BCS) coverage can inhibit wind erosion. This study used wind tunnels to analyze the wind erosion and particulate matter emissions of algae crusts and moss crusts for different wind speeds and coverage conditions, providing the proportion of particulate matter emission of the total wind erosion under different conditions. Wind erosion of algae crusts was 33% higher than that of moss crusts, and the average emissions of total suspended particles (TSP), PM10, PM2.5, and PM1 were 51%, 64%, 149%, and 167% higher than those of moss crusts. The wind erosion process pairs of the two biological soil crusts both had strong responses to wind speed and coverage, and particulate matter emissions were particularly sensitive to coverage. The average aerodynamic roughness length of moss crusts was 164% higher than that of algae crusts; with increasing wind speed, the aerodynamic roughness length of algae crusts decreased 60% faster than that of moss crusts. The proportion of particulate matter emissions from biological soil crusts in wind erosion was inversely proportional to wind speed and coverage. The particle emission capacity of moss crusts was directly proportional to the particle size and inversely proportional to the coverage. In contrast, the particle emission capacity of algae crust particles was proportional to the particle size. This study provides information for the management of farmland wind erosion and particulate matter emission.