This analysis examines deposition as a function of distance from the NH3 source complex, the fraction of emissions deposited locally, and the relative importance of individual exchange processes (i.e., stomatal, cuticular, and soil uptake) and surface types with respect to predicted net deposition rates. The results show that dry deposition rates near the source are high, though the highest deposition rates are rather limited in spatial extent. The results are consistent with European studies which show that the majority of emitted NH3 is transported away from the source and is therefore available for aerosol formation and deposition to downwind ecosystems. The results demonstrate the need for a more mechanistic treatment that takes into account flux bi-directionality. However, such an effort
clearly requires additional measurements of canopy- scale net fluxes, as well as soil and vegetation chemistry, within the primary land-use types.