What was found
AIR QUALITY EVENT, SEE AIR QUALITY REPORTING FORM. FLIGHT PHASE AT START OF EVENT: DESCENT, 4000'. DESCRIPTION OF ODOR/FUMES: CONTINUOUS AND DISCOMFORTABLE, DIRTY SOCKS AND MUSTY DRY SMELL. APPARENT CABIN SOURCE: CABIN AIR SUPPLY VENTS. FLIGHT DECK, FWD CABIN/GALLEY(LAV), MID CABIN, AFT CABIN/GALLEY(LAV). NO VISIBLE SMOKE/HAZE. NO MEDICAL ATTENTION REQUIRED.-PERFORMED TSM 05-50-00, PERFORMED DECONTAMINATION OF PACK #1 AND #2 IAW AMM 21-00-00-615-802, PERFORMED ENG RUN #1 AND #2 IAW AMM 71-00-00, NO SMELL NOTICED AT THIS TIME. A/C BACK TO SERVICE.