MODELING THE ATMOSPHERIC CHEMISTRY OF MERCURY - THE IMPORTANCE OF A DETAILED DESCRIPTION OF THE CHEMISTRY OF CLOUD-WATER

A model describing the aqueous chemistry and mass transfer processes of atmospheric mercury (Hg) has been used for analyzing the influence of various chemical and physical parameters on aqueous Hg concentrations. The model involves 39 gas phase species in 79 reactions and 32 aqueous species in 93 reactions. Modeled concentrations are in the range 2 to 5 and 5 to 10 ng L(-1) for dissolved and total Hand respectively. Accurate descriptions of gas phase as well as aqueous phase chemistry of oxidants, acidifying substances and chlorine chemistry are necessary since there is a complex relationship between a number of species and the aqueous Hg concentrations. Of the physical parameters studied the influence of the assumed fog liquid water content was also found to be of great importance.