Mercury two-phase box model

Mercury is one of the most toxic metals found in nature in a variety of physical and chemical forms. The interconversions of different forms of Hg strongly influence the deposition rate. Therefore, the knowledge of atmospheric Hg chemistry is crucial to understand the fate and transport of Hg in the environment. Two-phase mercury box model is developed based on the up-to-state mercury mechanisms both in the gas phase and in the liquid phase. In the gas phase, mercury reactions with the halogen, ozone and OH radicals are included as well as the interchange of mercury oxide (HgO) between the gas phase and the liquid phase. In the aqueous phase, both chemical (Hg0°êHg2+) and physical (Hg adsorption on the soot) mercury mechanisms along with sulfite and oxygen aqueous reactions are described in this model. The model is used to evaluate the key reactions steps under several different atmospheric conditions. The sensitivity the alternations of parameters, initial conditions and assumptions regarding for chemical mechanisms are investigated. Results from this study will be used in a 3-D model to provide a better understanding of the regional and global distributions of Hg.