1999 Improved Ammonia Emission Inventory by County in Tennessee

Ammonia gas reactions in the atmosphere are a significant source of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5um). Due to the increasing concentration of PM2.5 in the atmosphere, the need for improved ammonia emission inventories has become an increasingly important air quality issue. This study produced ammonia emission estimates for ten source categories and fifty- four sub-source categories for the State of Tennessee on a county basis for the year 1999. Livestock is a major source of total ammonia emissions in Tennessee, responsible for emitting 88,000 tons per year, with beef cows emitting 45,000 tons of ammonia emissions and forming the biggest sub-source category within the livestock category. Even though soil may be an uncertain source category of ammonia emissions and some double counting of emissions may occur in the fertilizer source category, soil was estimated to emit 61,000 tons of ammonia emissions as the second highest contributor. In some urban counties in Tennessee, mobile sources were the largest source of ammonia emissions. Ammonia emissions were estimated on a county basis from 54 source categories for all counties in Tennessee. In addition, this study includes recommendations for the use of spatial surrogates to allocate emissions for area sources, and temporal profiles for allocating emissions by season and time of day. The spatial and temporal allocations of emissions are needed for modeling PM2.5 formation.