Abstract: A ventilation system having a hood located above cooking equipment which generates heat and fumes due to cooking. The hood has an inclined air filter at the back of the hood which rests on a flange extending along the length of the hood at the top thereof and the bottom of the inclined air filter rests on a grease collector extending along the length of the hood. The grease collector is located at a given distance downwardly from the top of the hood. The back of the inclined air filter defines an exhaust area, and the hood also includes an exhaust duct being in direct communication with the exhaust area and a fan for drawing the contaminated air out of the exhaust area. The hood also has a fresh air output that is connected to a fresh air duct including a fan and located along the length of the hood at the front thereof, this fresh air output being designed to inject fresh air into the hood.