The average measured concentrations (M), shown as black circles, are shown along with the model estimates for the base case (1A) and other model configurations for each site with 2005 data included in the analysis. Data for Hg(II) (left), Hg(p) (center) and total non-Hg(0) (right) mercury forms are shown. The total non-Hg(0) model estimates include Hg2s, as well as Hg(II) and Hg(p). Hg(II) model results are compared against measurements generally reported as Gaseous Oxidized Mercury (GOM). Hg(p) model results – representing the total particle-associated mercury over all size ranges – are compared against fine-particle mercury measurements, which typically include only particles smaller than 2.5 um. Unless otherwise specified, model concentrations are reported for the lowest model layer (L2), i.e., the layer closest to the earth’s surface (L1 is defined as the surface itself). For sites in more complex terrain, model results for additional model elevations or “levels” (L2, L3, etc.) are shown. All concentrations are reported at 0^oC and 1 atm, and the comparisons are made only for the specific times during 2005 that measurements were made.