I am trying to run HYSPLIT (PC version) for Mercury (emit in gas phase). For chemical depositon set up, the model asks for Surface Reactivity Ratio, Diffusivity Ratio, and Effective Henry’s Constant. At this time I could not find any of these properties for (Hg+2 or HgO). I wonder is there anyone who did this pollutant simulation before. Any suggestion about where to obtain this information would be appreciated.

There are at least three research teams who have used HYSPLIT for Hg modeling: N. Pirrone in Italy, G. Keeler at the Univ of Michigan, and myself here at NOAA. Pirrone and myself have made extensive modifications to HYSPLIT, i.e., we are not using the “off-the-shelf” version, but are independently developing research-grade models. Keeler’s group at University of Michigan in Ann Arbor is using a number of models for their Hg research, but has used the “off-the-shelf” version (more or less) to try to simulate Hg. I’m not sure if they’ve published anything on this or not, however.

Hg(+2) is going to be relatively sticky, while Hg(0) is not, so one should probably use a relatively high surface reactivity ratio for Hg(+2) and a relatively low one for Hg(0).

Henry’s Law constants for these species have been published in a number of places, e.g., the review by Schroeder and Munthe, Atmos Envr, 32(5), pp 809-822, 1998.

As far as diffusivity ratio goes, you might see if you can find out what Keeler used. I would guess it would be close to 1 for these compounds.

Mark Cohen