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NARSTO Workshop on Innovative Methods for Emission Inventory Development and Evaluation University of Texas, Austin October 14-17, 2003 |
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Development of the Next Generation of an Ammonia Emission Inventory
Mark Janseen
LADCO
The purpose of this work is to develop a national mechanistic model of ammonia emissions from the top four livestock categories: hogs, poultry, beef cattle, and dairy cattle. This partially mechanistic model would be derived from the work of Robert Pinder at Carnegie Mellon University. This model would combine experimental results and physical principles to explain variations in emissions rates with a focus on temporal and geographic variation. This project seeks to extend his work on dairy cattle to include the other three categories of livestock. The model would use a combination of local climatological and meteorological data including ambient temperature, precipitation, and wind speed. It will also include a national farming practices model incorporated at the county level so that variation in local farming practices can be reflected in the model. These farming practices data include animal housing, waste storage, seasonal confinement, and a waste spreading calendar. Pinder´s techniques needs to be extended in several important ways. While his model focuses on the development of annual emissions inventories based on seasonal average temperatures, chemical transport models need emission estimates for each hour of each day of the year gridded cells as small as 4km. It will, therefore, be necessary to make the model read the gridded hour- and day-specific meteorological fields and calculate emissions for a specific hour and day and a model grid cell. Recent chemical transport modeling suggests that the hourly variation of ammonia emissions is important in understanding particulate nitrate formation.