An improvement for a production line, downdraft type paint spray booth having a conveyor for carrying the parts to be painted, having a recessed portion for containing the conveyor and dual slots, on one or either side of the conveyor for air flow is disclosed.The improvement provides the advantage of improved air flow around the parts being painted and around the conveyor to keep it clean. Additionally, the provision of the dual slots permits the conveyor to be at least partially recessed into the booths floor to provide a lower profile and a more compact arrangement.