AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Livestock Ammonia Emissions: From Process-based Farm Emissions Models to a New National Inventory for Beef, Swine, and Poultry in the United States
ALYSSA MCQUILLING, Peter Adams, Carnegie Mellon University
Abstract Number: 310 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Ammonia is a critical air pollutant, and its emissions from livestock production have been largely exempt from regulation (Centner et al. 2010; Smith et al. 2013). Before regulations can be imposed, ammonia emissions from livestock, which depend on manure management, nutrition, and meteorology, must be better understood. Based on the earlier work of Pinder et al. (2004), process-based farm emission models (FEMs) have been developed for beef, swine, and poultry emissions, and constrained by literature data. The FEMs allow us to capture seasonal and regional variability in ammonia emissions due to varying climate and manure management practices. The FEM performance was better for emissions sources with better input information and for enclosed sources, compared to open sources like feedlots or lagoons (r-squared value for swine housing is 0.67, while feedlot r-squared is 0.21-0.36). Recent data from the National Air Emissions Monitoring study (NAEMS) offers independent data to help evaluate and improve farm-level models. Comparison of emissions predictions from FEM models versus the NAEMS measurements show that the FEMs often under-predict emissions at colder temperatures, but in some cases, NAEMS measurements are noticeably different than prior measurements in the literature (NAEMS emissions are up to 10-15x higher than literature for swine lagoons). Model re-tuning is ongoing to improve agreement among the literature, NAEMS and model results. The next step toward producing a process-based ammonia emission inventory is to use a statistical model to predict the distribution of manure management practices for each county in the country and for each animal type—beef, swine, and poultry. By combining the results from the FEMs and the national practices, we produce inventories for major livestock types that capture seasonal and regional variability in ammonia emissions. Data regarding national practices are from the National Animal Health Monitoring Survey and the USDA National Agricultural Census.