What was found
AIRCRAFT 3022, AT 3000 AFTER THE DESCENT ON THE ARRIVAL WE NOTICED A VERY ODD AND DISCOMFORTING SMELL. BOTH PILOTS DONED O2. SMELL WAS ONLY NOTICED IN THE FLIGHT DECK. UPON LANDING THE SMELL DISIPATED. BLEEDS ON ENGINES, APU OFF, BOTH PACK ON. CLEANED AREA INSIDE APU COMPARTMENT, AND DECONTAMINATED BLEED AIR DUCT AND REPLACED LEFT ECS PRIMARY HEAT EXCHANGER. (LP 7529866)