Low Dust Generation Potential From Active Sand Grains by Wind Abrasion

Wind-driven dust emission has a major impact on many environmental and socioeconomic issues such as climate change, soil loss, biogeochemical cycles, and air pollution. It is generally assumed that the main global dust sources consist of nonsandy soils with high percentages of fine-sized clay and silt particles. However, in recent years, it has been hypothesized that active sand bodies can generate significant dust emissions through the mechanism of sand abrasion. Moreover, sand abrasion has been used to explain the formation of certain soils on Earth and Mars. Here, we test the hypothesis that sand abrasion can generate substantial dust emissions by performing targeted wind tunnel experiments on sand grains in the absence of clay and silt particles. We find only minor emissions of particulate matter from noncoated active sands under wind conditions typical of natural sand transport. The findings suggest that the dust generated by the mechanism of sand abrasion is less than dust generated by the removal of clay minerals coated on sand grain surfaces; both mechanisms on active sands produce far less dust than nonsandy soils. Feldspar sand was found to be slightly more effective at generating dust through abrasion than quartz sand. However, due to the low spatial coverage of feldspar sands in active sands worldwide, dust generated from feldspar abrasion may produce a relatively small contribution to global dust emissions. We thus conclude that sand abrasion by wind transport has a low potential to generate dust-sized particles from active sands.