A wood-strand material for wind erosion control: effects on total sediment loss, PM10 vertical flux, and PM10 loss

Generation, Resuspension, and Transport of Particulate Matter From Biochar-Amended Soils: A Potential Health Risk

Large-scale soil application of biochar is one of the terrestrial carbon sequestration strategies for future climate change mitigation pathways, which can also help remove and sequester pollutants from contaminated soil and water. However, black carbon emissions from biochar-amended soils can deteriorate air quality and affect human health, as the biochar particles often contain a higher amount of sorbed toxic pollutants than the soil. Yet, the extent and mechanism of inhalable particulate matter (PM10) emission from biochar-amended soils at different wind regimes have not been evaluated. Using wind tunnel experiments to simulate different wind regimes, we quantified particulate emission from sand amended with 1-4% (by weight) biochar at two size fractions: with and without <2-mm biochar. At wind speeds below the threshold speed for soil erosion, biochar application significantly increased PM10 emission by up to 400% due to the direct resuspension of inhalable biochar particles. At wind speeds above the threshold speed, emission increased by up to 300% even from biochar without inhalable fractions due to collisions of fast-moving sand particles with large biochar particles. Using a theoretical framework, we show that particulate matter emissions from biochar-amended soils could be higher than that previously expected at wind speeds below the erosion threshold wind speed for background soil. Our results indicate that current models for fugitive dust emissions may underestimate the particulate matter emission potential of biochar-amended soils and will help improve the assessment of biochar emission from amended soils.

An Assessment of the Impact of Urbanization on Soil Erosion in Inner Mongolia

Inner Mongolia, an autonomous region of the People’s Republic of China, has experienced severe soil erosion following a period of rapid economic development and urbanization. To investigate how urbanization has influenced the extent of soil erosion in Inner Mongolia, we used urbanization and soil erosion data from 2000 through 2010 to determine the relationship between urbanization and soil erosion patterns. Two empirical equations—the Revised Universal Soil Loss Equation (RUSLE) and the Revised Wind Erosion Equation (RWEQ)—were used to estimate the intensity of soil erosion, and we performed backward linear regression to model how it changed with greater urbanization. There was an apparent increase in the rate of urbanization and a decrease in the area affected by soil erosion in 2010 compared to the corresponding values for 2000. The urban population stood at 11.32 million in 2010, which represented a 16.47% increase over that in 2000. The area affected by soil erosion in 2000 totaled 704,817 km², yet it had decreased to 674,135 km² by 2010. However, a path of modest urban development (rural–urban mitigation) and reasonable industrial structuring (the development of GDP-2) may partially reduce urbanization’s ecological pressure and thus indirectly reduce the threat of soil erosion to human security. Therefore, to better control soil erosion in Inner Mongolia during the process of urbanization, the current model of economic development should be modified to improve the eco-efficiency of urbanization, while also promoting new modes of urbanization that are environmentally sustainable, cost-effective, and conserve limited resources.