An exhaust hood includes a housing, which is open towards a bottom face to capture cooking by-products from a cooking appliance positioned below the exhaust hood. The housing has at least a first wall and a second wall opposite to the first wall. The second wall is at least partly inclined inwardly from the bottom face towards a top face of the housing and has an exhaust vent that communicates with an exhaust fan to extract cooking by-products captured by the housing. The exhaust hood has a fresh air fan and the first wall is shaped to form a first duct which has a number of openings located in a row along a lower edge of the first wall adjacent to the bottom face and oriented to the inside of said housing. The first duct is in communication with the fresh air fan to inject air streams through the openings into the housing in a direction substantially parallel to the bottom face. This creates a vertical flat air stream directed from the first wall towards the second wall. The openings may be substantially rectangular slots, the long edges of which are oriented in parallel to said bottom face. The exhaust hood can have a baffle sheet located at the inside of the first wall above the row of openings, which extends into the housing substantially parallel to the bottom face.