|Maghirang, Ronaldo - Kansas State University|
|Bonifacio, Edna - Kansas State University|
Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2014
Publication Date: 1/20/2015
Citation: Bonifacio, H.F., Maghirang, R.G., Trabue, S.L., Mcconnell, L.L., Prueger, J.H., Bonifacio, E.R. 2015. TSP, PM10, and PM2.5 emissions from a beef cattle feedlot using the flux-gradient technique. Atmospheric Environment. 101:49-57.
Interpretive Summary: Particulate matter (PM), or dust, emitted from larger cattle feedlots can cause adverse impact on both human health and environment. PM is typically classified according to its particle size: total suspended particles (TSP) include PM of all sizes; PM10 is PM with aerodynamic diameter of 10 µm or less – PM of this size can be inhaled and enter the respiratory system; and PM2.5 is PM with diameter of 2.5 µm or less – this PM is commonly referred to as fine particles and can penetrate the inner regions of the lungs. Characteristics of PM emitted from feedlots and how much can be released into the air are important information that can be used by researchers, regulatory officials and feedlot operators for improvement/development of practices and methods that can lower feedlot PM emissions, and for assessing impact of PM emitted on areas downwind of feedlots. This is the first study that simultaneously measure feedlot PM emissions according to size. Concentrations of TSP, PM10 and PM2.5 were measured at a cattle feedlot in Kansas, and these measurements were used in calculating TSP, PM10 and PM2.5 emission rates using the flux-gradient technique, a tool commonly applied for estimating emissions from area sources such as feedlots. Determined PM emission rates in this study can be added to the limited research-based data on feedlot PM emissions. When assessing impact on downwind areas, PM emission rates presented can be applied for feedlots located in the US Midwest region and those with the same feedlot/climate conditions. In addition, results of this study implied that keeping the surface of the feedlot pens moist (20 to 30% water content) would be an effective practice in reducing the overall feedlot PM emissions.
Technical Abstract: Emissions data on air pollutants from large open-lot beef cattle feedlots are limited. This research was conducted to determine emissions of total suspended particulates (TSP) and particulate matter (PM10 and PM2.5) from a commercial beef cattle feedlot in Kansas (USA). Vertical particulate concentration profiles at the feedlot were measured using gravimetric samplers, and micrometeorological parameters were monitored with eddy covariance instrumentations during the nine 4- to 5-day intensive sampling campaigns from May 2010 through September 2011. Emission fluxes were determined from the measured concentration gradients and meteorological parameters using the flux-gradient technique. PM ratios based on calculated emission fluxes were 0.36 for PM2.5/PM10, 0.12 for PM2.5/TSP, and 0.29 for PM10/TSP, indicating that a large fraction of the PM emitted at the studied feedlot was in the coarse range of aerodynamic diameter, >10 'm. Median daily emission factors were 56, 21, and 11 kg 1000-head (hd) -1 d-1 for TSP (n = 20 days), PM10 (n = 19 days), and PM2.5 (n = 11 days), respectively. Cattle pen surface moisture contents of at least 20 to 30% significantly reduced both TSP and PM10 emissions, but moisture’s effect on PM2.5 emissions was not established due to difficulty in measuring PM2.5 concentrations under low-PM conditions.