Modelling and analysis of the atmospheric nitrogen deposition in North Carolina

The United States Environmental Protection Agency's Community Multiscale Air Quality (CMAQ) regional-scale model is used to study concentrations and dry deposition of nitrogen species in North Carolina (NC) during the summer season. Each modelled and measured species featured a similar diurnal trend. A process budget analysis (production and removal evaluation) of NO, NO2, and NOY depicted the model's capability to evaluate various process contributions. Dry deposition of NH3 contributed 34.2 ± 57.9 µg N m-2 hr-1; whereas HNO3 contributed slightly larger dry deposition of nitrogen, 35.2 ± 16.0 µg N m-2 hr-1, in NC. NH4+ and NO3- hourly-averaged wet deposition fluxes were calculated as 37.3 ± 19.7 µg N -2 hr-1 and 40.6 ± 11.8 µg N m-2 hr-1, respectively. Examination of total nitrogen deposition during the summer season in NC found that NH3 contributes approximately 50% of the dry deposition and NO3- contributes approximately 50% of the wet deposition.