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Varying Terrain Height

How do you handle different terrains in EPZ and LPZ in small areas?

For elevated releases (only), terrain is used to reduce the effective plume height. Up to 10 downwind terrain distances can be specified for a sector and each sector must use the same number and distances. The terrain height should be the maximum terrain height above plant grade between the release point and downwind distance in that sector. Please refer to page 25 of the PAVAN User Guide (pdf version) for information on entering terrain height. Test case #2 in the User Guide shows an example using terrain heights. For short downwind distances to the exclusion area boundary (EAB) and low population zone (LPZ), you may find that one or two terrain heights suffice.