A semiconductor manufacturing process facility requiring use therein of air exhaust for its operation, such facility including clean room and gray room components, with the clean room having at least one semiconductor manufacturing tool therein, and wherein air exhaust is flowed through a region of the clean room. The facility includes an air exhaust treatment apparatus arranged to (i) receive air exhaust after flow thereof through said region of said clean room, (ii) produce a treated air exhaust, and (iii) recirculate the treated air exhaust to an ambient air environment in the facility, e.g., to the gray room of the facility.