Deposition of Nitrogen and Sulfur to Louisiana Water Bodies

Hao Guo, Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA, 70803, hguo8@lsu.edu; Fenglin Han, Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA, 70803, fhan3@lsu.edu; and Hongliang Zhang, Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA, 70803, hlzhang@lsu.edu.

Wet deposition and dry deposition reduce their concentrations of sulfur and nitrogen contained air pollutants in atmosphere, but lead to increase of sulfur and nitrogen fluxes to the surface. Atmospheric deposition of sulfur and nitrogen can lead to acidification of surface water bodies (lakes, rivers, and coasts) and subsequent damage to aquatic ecosystems as well as damage to forests and vegetation. Louisiana has abundant water resources with approximately 11% of the total surface area composed of water bodies. It is important to protect water resources from excessive atmospheric deposition of sulfur and nitrogen. However, the information obtained from the observation systems for understanding the deposition of sulfur and nitrogen and the adverse effects in Louisiana is limited.

This study uses a source-oriented CMAQ model to simulate emission, formation, transport, and deposition of sulfur and nitrogen species in Louisiana. WRF is used to generate the meteorological inputs and SMOKE is used to generate the emissions based on national emission inventory (NEI). The forms and quantities of sulfur and nitrogen deposition from wet and dry processes in Louisiana will be discovered. The spatial and temporal variations of sulfur and nitrogen fluxes will be quantified and contributions of major source sectors or source regions will be quantified.