Characterization of Atmospheric Ammonia Plumes from Commercial Chicken Houses on the Delmarva Peninsula

A unique three-dimensional sampling grid using passive collectors was used to characterize the downwind gas-phase ammonia plumes originating from a commercial chicken house on the Delmarva Peninsula in the Chesapeake Bay watershed. Inverse Gaussian plume modeling was used to determine the source strength of the chicken house and the corresponding chicken emission factors. A total of 7 field deployments were performed during 2 different flocks. The deployments occurred during weeks 3, 4 and 5 of the 6-week chicken grow out period in the months of May, June and July of 2002. The ammonia emission factors ranged from 0.27 ± 0.18 g NH₃-N bird-1 day-1 to 2.17 ± 0.30 g NH₃-N bird1 day-1 with a mean of 1.18 g NH₃-N bird-1 day-1. Weighted emissions factors were also calculated to account for the nonlinear increase in ammonia emissions over the 6-week grow out period and ranged from 0.14 ± 0.09 g NH₃-N bird-1 day-1 to 1.65 ± 0.36 g NH₃-N bird-1 day-1 with a mean of 0.74 g NH₃-N bird1 day-1. These weighted emission values would correspond to an annual release of approximately 18 x 106 kg NH₃-N to the atmosphere from broiler production on the Delmarva Peninsula. This assumes that the emission factors in this study are representative for the entire year with varying meteorological conditions and are representative of all chicken husbandry practices. The Delmarva Peninsula could represent a significant source of nutrient nitrogen to the Chesapeake Bay and Delaware Bay watersheds through atmospheric deposition when considering the size of this annual release rate, the relative short atmospheric lifetime of ammonia due to deposition, and the proximity of the Delmarva Peninsula to the Chesapeake and Delaware Bays.

⁽¹⁾ University of Maryland, Center for Environmental Science, Chesapeake Bay Biologica Laboratory
⁽²⁾ University of Delaware, Graduate College of Marine Studies
⁽³⁾ University of Maryland Eastern Shore
* Corresponding Author, Telephone: (410) 326-7586, FAX: (410) 326-7341, E-mail: siefert@cbl.umces.edu