What was found
DTW - FLT 1932 - DURING TAKEOFF DFW, FLIGHT CREW NOTED ACRID SMELL AND HAZE IN CABIN. CREW TURNED OFF RECIRCULATING FAN AND INCREASED TEMPERATURE, HAZE, AND SMELL DISSIPATED. AIRCRAFT CONTINUED TO DTW WITH NO FURTHER SMELL NOTED UNTIL DESCENT WHEN SMELL RETURNED. AIRCRAFT LANDED DTW WITHOUT FURTHER INCIDENT. AIRCRAFT WAS TAKEN OUT OF SERVICE AND MAINTENANCE REPLACED BOTH AIR CYCLE MACHINES AND ACCOMPLISHED BURN-OUT PER MM PROCEDURES. SYSTEM GROUND AND LEAK CHECKED, NORMAL OPERATION. REF: OPER CONTROL NR 98ZZZX1934. (X)