Keywords: ammonia, CMAQ model, Community Multiscale Air Quality model, dry deposition, flux, modelling, nitrogen concentration, wet deposition, air pollution
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.