What was found
(CAN) STRONG SMELL IN COCKPIT ON TAKEOFF, LIGHT SMOKE OR HAZE IN CABIN. CARRIED OUT AIR CONDITION SMOKE CHECK LIST, PACK NR ONE TURNED OFF. ON LANDING, SMOKE DISAPPEARED DURING RETURN. REPLACED RECIRCULATION FILTERS, BOTH ENGINES GROUND RUN WITH BOTH PACKS ON. NO SMOKE OR ODOR FOUND.