The exhaust hood duct in a commercial kitchen needs to run to the roof. In cases that the exhaust duct from the kitchen hood cannot run to the roof, for example, a restaurant improvement in an existing building where it is not possible to run the exhaust duct through the above floor to the roof, the exhaust duct can be ran through the exterior wall to the outside. In this case the local code requirement including the pollution control for protection of the people on the sidewalk must be considered. For this purpose Pollution Control Units (PCU) are specifically designed to eliminate both smoke and grease particles from the kitchen exhaust system, and odor removal modules can eliminate or reduce odors to acceptable levels.
