Effective stack height

From Glossary of Meteorology

effective stack height

The final equilibrium height of the centerline of an effluent (smoke) plume from a smokestack or other source.

The effective stack height is the sum of the actual physical height of the top of the stack, plus any plume rise due to buoyancy or initial momentum (inertia) of the rising effluent, minus any downwash such as stack downwash, building downwash, or terrain downwash. The downwashes are associated with wake turbulence behind objects on the ground.