How do you vent a range hood in a rowhome with no side walls?

With party walls on both sides, a hood can only exhaust through the rear wall, up through the roof, or not at all. NK Construction & Design plans the duct route during design: a short run through the back wall is best, a roof penetration works when the kitchen sits under a flat rear roof, and a recirculating hood is the fallback when neither is possible. Gas ranges and larger cooktops push the decision toward a ducted hood.