PM2.5 and PM10 emissions from agricultural soils by wind erosion

Soil tillage and wind erosion are two major emission sources of particulate matter less than 2.5 and 10 mu m in size (PM2.5 and PM10) from cultivated soils. Samples from fifteen cultivated soils from five states of the US, both crushed (<2.0 mm) and uncrushed (natural aggregation), were tested for PM2.5 and PM10 emissions in a wind tunnel, at 8, 10, and 13 m s(-1) wind velocities. In addition, 10 soils were paired as conventional vs. no-till. Results showed that: (1) PM2.5 and PM10 emissions of crushed and uncrushed samples increased with wind speed, with a more rapid and greater emissions trend for crushed samples; after three wind speeds, mean PM2.5 and PM10 emissions from crushed soils were 1.3-8.5 and 1.9-10 times that of uncrushed soils; (2) PM2.5/PM10 ratios of crushed and uncrushed samples were, respectively, 0.11-0.45 and 0.13-0.46, and the mean PM2.5/PM10 ratio of uncnshed samples was higher; (3) PM2.5 and PM10 emissions of tested soils showed a significant negative power function relationship with clay content and PM2.5 and PM10 fractions of the dispersed soil samples, whereas the sand content and <0.42-mm aggregate content of the samples showed a significant linear positive correlation with emissions; and (4) although not significant, no-till soils had consistently lower PM2.5 and PM10 emissions than paired conventional tilled soils for uncrushed samples. Published by Elsevier B.V.