A Sensitivity Analysis on Atmospheric Transportation of Mercury in Guiyang China

The article presents the results of sensitivity study on the factors that affect air mercury transportation by using model MESO-NH to simulate air mercury transport for Guyang city during Jan. 28-30, 2004. The factors are emission, dry deposition velocity of Hg⁰, dry deposition velocity of HgP, rate constant of Hg⁰ oxidation by OH. The results show that (1) air mercury concentrations are sensitive to dry deposition velocity of Hg⁰ in the places where air mercury concentrations are high, and are not sensitive in the place where air mercury concentrations are low. (2)Only the area near sources is affected by reducing mercury emission from anthropogenic sources within Guiyang by 50%, almost no effect on the area far from the sources where air mercury concentrations are resulted from global and regional long-rang transport. (3) Air mercury concentrations are sensitive to the rate constant of Hg⁰ oxidation by OH generally. With bigger rate constant, Hg⁰ has lower percentage in the air, and Hg(II) and HgP have higher percentages; contrarily with smaller rate constant k_HgP._0H=2.94E-14 mol/cm³/s, which the simulation results are close to the monitoring values. (4) The results are similar in the area far from sources with both dry deposition velocities of Hd_HgP=0.625 cm/s and Vd_HgP=0.225 cm/s; but with Vd_HgP=0.225 cm/s, Hg⁰ percentage is lower, and the percentages of Hg(II) and HgP are higher. The simulation results with Vd_HgP=0.625 cm/s are closer to the monitoring values.