Comparison of Partial Reactive Organic Gases (ROG) Emission Factors from a Dairy and Beef Feedlot

Abstract

Emission factors are fundamental tools for estimating the total emission of certain criteria pollutants from a particular source at a given time. In this work we performed a new protocol similar to EPA method TO-14A, suggested by Capareda et al. (2005) in determining ROG emissions from animal feeding operations. Fourteen (14) ROG were tentatively identified and quantified from the dairy and beef feedlot located at Central Texas and Texas Panhandle, respectively during summer of 2006. The compound groups found include ketones, aldehydes, alcohols, volatile fatty acids, benzothiazole, phenols and p-cresol. We found that the relative amounts of ROG in the dairy were much higher than in the beef feedlot and the volatile fatty acids (VFAs) group being more dominant than the other compound groups. Cattle wastes (i.e. manure and urine), milk and some dairy produce are considered as major contributors of biogenic ROG and could be the main reason for the difference. Meanwhile, acetic acid was selected among the volatile fatty acids and its concentration and emission factor were determined for both the sampling locations. It was found that the average emission factor of acetic acid in the dairy open feedlot (ca. 775 kg 1000-hd -1 yr -1 ) was more than four times the magnitude of emission factor in the beef cattle openlot (ca. 186 kg 1000-hd -1 yr -1 ). However, the analysis and characterization of the data using the suggested protocol does not include the full suite of ROG emissions from the dairy and beef cattle feedyards.