Particulate matter emission rates from beef cattle feedlots in Kansas—Reverse dispersion modeling

摘要

Open beef cattle feedlots emit various air pollutants, including particulate matter (PM) with equivalent aerodynamic diameter of 10 μm or less (PM_(10)); however, limited research has quantified PM_(10) emission rates from feedlots. This research was conducted to determine emission rates ofPM_(10)from large cattle feedlots in Kansas. Concentrations ofPM_(10) at the downwind and upwind edges of two large cattle feedlots (KS1 and KS2) in Kansas were measured with tapered element oscillating microbalance (TEOM) PM_(10) monitors from January 2007 to December 2008. Weather conditions at the feedlots were also monitored. From measured PM_(10) concentrations and weather conditions, PM_(10) emission rates were determined using reverse modeling with the American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model (AERMOD). The two feedlots differed significantly in median PM_(10) emission flux (1.60 g/m~2-day for KS1 vs. 1.10 g/m~2-day for KS2) but not in PM_(10) emission factor (27 kg/1000 head-day for KS1 and 30 kg/1000 head-day KS2). These emission factors were smaller than published U.S. Environmental Protection Agency (EPA) emission factor for cattle feedlots. Implications: This work determined PM_(10) emission rates from two large commercial cattle feedlots in Kansas based on extended measurement period for PM_(10) concentrations and weather conditions, and reverse dispersion modeling, providing baseline information on emission rates for cattle feedlots in the Great Plains that could be used for improving emissions estimates. Within the day, PM emission rates were generally highest during the afternoon period; PM emission rates also increased during early evening hours. In addition, PM emission rates were highest during warm season and prolonged dry periods. Particulate control measures should target those periods with high emission rates.