Measuring Cattle Feedlot Dust Using Laser Diffraction Analysis

Measuring Cattle Feedlot Dust Using Laser Diffraction Analysis Authors: H.B. Gonzales, R.G. Maghirang, J.D. Wilson, E.B. Razote, L. Guo Submitted to: Transactions of the ASABE Open beef cattle feed lots can emit considerable amounts of particulate matter. The combined effects of warm temperature, low humidity and high wind speed can promote rapid water evaporation from the pen surface, making particulates susceptible to air suspension. Emitted particles have human health and environmental effects such as vascular inflammation, atherosclerosis, an increased incidence of asthma and other respiratory problems. Rapid and accurate determination of particulate size distribution of this air borne dust is crucial in developing management policy for improved both human and livestock health in these large feed lots. These studies compares and contrasts laser diffraction analysis to a standard cascade impactor as well as determine meteorological factors and sampling period on dust particle size distribution. This study took place in a large commercial feedlot in Kansas over two years. The laser diffraction analysis and the cascade impactor did not differ significantly of the geometric mean diameter of the dust particles, consequently could be used interchangeably. Wind speed and period of sampling (day vs. night) significantly affected the measured geometric mean diameter of the particles, while increasing pen surface water content decreased large (<10μm ) to small (<2.5 μm) fractions. Contact Jeff Wilson, telephone 785-776-2763, email [email protected]