1. Using CATT to Calculate MGM (Mark Green Method) Incremental Probabilities and for Calculating Receptor Average Concentrations by Upwind Location Note: Rudy & Co. will likely add these metrics to CATT tools for automated calculations, But meanwhile, here’s some tricks (a 10-step program) to make the calculations with a bit of manual labor. For other CATT tricks, see also: http://www.anr.state.vt.us/air/Planning/PublicDocs/FastCatMV3.ppt http://www.anr.state.vt.us/air/Planning/PublicDocs/FastCatMV3.ppt

2. 1.Open Data Viewer: http://webapps.datafed.net/dvoy_services/datafed.aspxhttp://webapps.datafed.net/dvoy_services/datafed.aspx 2.Pulldown: File, Open Page, allgrid - to open plain jane gridder The default view is an everyday gridded trajectory endpoint file for Lye Brook

3. This is a (4000 row) gridded All Day Trajectory Endpoint Count for the selected site

4. 7. Then redo steps 3 & 4 and paste the new data into same Excel spreadsheet (The gridded values include nulls and the rows will line up correctly)

5. 8. Calculate the “Incremental Probability” (by the Mark Green Method) by first normalizing both the unweighted and weighted endpoint counts (divide each grid cells value by sum in all grid cells), then subtract normalized unweighted values from normalized weighted values. 9. Calculate “Average Receptor concentration by Upwind Location by dividing weighted endpoints by unweighted endpoints 10. Repeat steps 1-9 for other sites or species, save as tab-delimeted text, and open in Arcview (with Spatial Analyst) for additional interpolation and plotting

6. Site-specific & regional average Sulfate Inc. Probs for MANE-VU & Nearby sites

7. Comparison of MV Regional average Inc. Probs. & Average Upwind SO4 Why does regional average Upwind SO4 have such a long curving tail? Could this be indicative of “Bermuda High” Classic Sulfate Episode Meteorology?

8. Why is (urban) WASH DC site so different from the others? That southern lobe can’t possibly be Atlanta, can it?