AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Development of a Process-Based Model for the Estimation of Beef Cattle Ammonia Emissions
ALYSSA MOORE, Peter Adams, Carnegie Mellon University
Abstract Number: 763 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Ammonia is an important air pollutant because it is an irritant and a precursor to the formation of fine particulate matter in the atmosphere. The livestock industry emits between 70-90% of ammonia emissions in the United States, and the largest emitters are dairy and beef cattle, swine and poultry. Beef cattle contribute more than 25% of livestock ammonia emissions, so it is important to better understand and estimate ammonia losses from beef cattle excrement to improve manure management and reduce impacts of livestock production on air quality. Practices used in the production of beef cattle vary regionally and depend on meteorological conditions. Measurements can help us estimate emissions for a specific set of practices and meteorology, but not all practices and meteorology can be measured, so a model that describes how emissions occur throughout the manure management process, also called a process-based model, will be used to estimate ammonia emissions from beef cattle. Using the model framework developed by Pinder, et al. (2004) for dairy cows and based on the governing equations of Hutchings, et al. (1996), we can tune the model to predict ammonia emissions from single beef farms. Preliminary results for several test farms indicate that beef emissions are somewhat lower than those from dairy cows, especially from those raised on pasture. Emissions also depend strongly on the ammonia concentration of the excrement as well as its pH and increase with increased temperature and wind speed and decrease with precipitation. Further work will tune model to reported beef emission factors. After validating the farm emission model, we will use this data to build up a national inventory for beef cattle ammonia emissions.