PM2.5 and PM10 emissions by breakage during saltation of agricultural soils

Authors: Tatarko, John; KUCHARSKI, MATTHEW - Former ARS Employee; LI, HONGLI - Shandong Agricultural University; LI, HUIRU - Beijing University Of Agriculture

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2020
Publication Date: 12/28/2020
Citation: Tatarko, J., Kucharski, M., Li, H., Li, H. 2020. PM2.5 and PM10 emissions by breakage during saltation of agricultural soils. Soil & Tillage Research. 208. Article e104902. https://doi.org/10.1016/j.still.2020.104902.
DOI: https://doi.org/10.1016/j.still.2020.104902

Interpretive Summary: When small soil clods blow in the wind, they break up and release fine dust into the air. Fine dust can enter human lungs and affect the health of humans around the world. Little is know about how fine dust particles that are less than 0.0001 inches or those less than 0.0004 inches in size are produced by soil wind ersoion. Both these sizes are regulated by the US-Environmental Protection Agency as health hazards. We used a laboratory wind tunnel to measure fine dust from breaking of small clods (0.006 to 0.03 inches in size) in the wind at 29 miles per hour for 15 soils from across the U.S. The amount of clod breakage depended on the amount of clay in the soil where high clay soils broke less than those with high sand content. The soil with the highest sand content was found to be have the greatest total dust produced. We did not find a relationship between soil type and the amount of dust less than 0.0001 or 0.0004 inches in size produced. We also compared fine dust generated for five soils that had long-term tillage histories of either conventional tillage (CT) or no-till (NT) agricultural management. CT soils tended to have higher sand, lower silt and lower organic matter than NT management. Three soils with the highest clay content had stronger clods and less fine dust was produced with NT than CT management. We also developed an equation to predict the fine dust from soils tested. This results of this study can be used to predict fine dust emissions from breaking of blowing clods on agricultural soils. It also provides information to help control of fine dust from wind erosion by agricultural management.

Technical Abstract: Breakage of soil aggregates during saltation is one process that contributes to the generation of fine dust emissions by wind erosion. Fine dust is also known to affect human respiratory health. Of particular hazard are particles of aerodynamic diameter less than 2.5 µm (PM2.5) and those less than 10 µm (PM10), both of which are regulated by the US-Environmental Protection Agency. We used a laboratory wind tunnel with wind at 13 m s-1 to investigate the emission parameters for PM2.5 and PM10 caused by saltation-size aggregates (0.15 to 0.84 mm) for 15 soils with a wide range in properties from across the U.S. The coefficient of breakage (Cbk) was found to vary inversely with clay content, with the largest values found for soils with the greatest sand content. Only one soil with the highest sand content was found to be statistically different in total suspension flux from breakage (Gssbk). We did not find a relationship between soil texture or organic matter and the soil fraction of PM2.5 and PM10 from breakage (SF2.5bk and SF10bk). In addition, five of the soils tested had long-term histories of either conventional tillage (CT) or no-till (NT) management for paired comparisons of emission based on management. CT soils tended to have higher sand, lower silt and lower organic matter than NT management. Management significantly affected Cbk for four of the five soil pairs where the three with the highest clay content having lower Cbk under NT than CT management and the fourth pair had lower Cbk under CT management. Long-term NT management showed significantly less vertical suspension flux from breakage during saltation (Gssbk) than CT management for only two of the five paired soils. A linear relationship predicted PM2.5 emissions from breakage as a fraction of PM10 emissions for the mineral soils tested (R2 = 0.972). This research contributes to our understanding of PM2.5 and PM10 emission during saltation. It also provides parameters that will improve fine dust simulation in the Wind Erosion Prediction System (WEPS) model.