Narrative:

Climbing through 18;000 ft.; the C flight attendant notified us of a dirty sock smell coming from the aft galley. We immediately followed the QRH procedure for cabin/cockpit fumes which resulted in us using oxygen and shutting off pack 2. After pack 2 was shutdown; fumes were reported to have dissipated. We consulted with dispatch and made the joint determination it was safe to continue and we would advise of any changes.near ZZZ; the flight attendants informed us of a musty; strong odor coming from the mid-cabin area. We again referenced the QRH checklist and consulted with dispatch. The odors did not dissipate this time so we [advised ATC]; began an emergency descent; informed the flight attendants and passengers of the new flight plan; and prepared for landing into ZZZ. We used maximum forward speed under PIC (pilot in command) emergency authority towards ZZZ to minimize passenger and crew exposure to the fumes. We prepared the aircraft for an overweight landing by following the overweight landing QRH procedure and determined we had adequate performance for landing and go-around at our estimated landing weight of around 172700 lbs. We landed uneventfully and taxied to the gate. I made a PA to all passengers to expeditiously deplane the aircraft and to leave bags so they could get off as quickly as possible. For everyone's safety; it was paramount to get everyone off as quickly as possible. We contacted dispatch about customs concerns but given the nature of the emergency it was not safe to leave anyone on the aircraft for any duration of time. After taking off my mask to exit the aircraft; I noticed the smell was noticeably strong in the cockpit and exited the aircraft expeditiously. The flight attendants were all suffering headaches and were checked out by EMS who met the aircraft.

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Original NASA ASRS Text

Title: A321 flight crew reported being advised of a dirty sock smell coming from the aft galley and then the mid cabin; resulting in a diversion.

Narrative: Climbing through 18;000 ft.; the C Flight Attendant notified us of a dirty sock smell coming from the aft galley. We immediately followed the QRH procedure for Cabin/Cockpit fumes which resulted in us using oxygen and shutting off PACK 2. After PACK 2 was shutdown; fumes were reported to have dissipated. We consulted with Dispatch and made the joint determination it was safe to continue and we would advise of any changes.Near ZZZ; the flight attendants informed us of a musty; strong odor coming from the mid-cabin area. We again referenced the QRH checklist and consulted with Dispatch. The odors did not dissipate this time so we [advised ATC]; began an emergency descent; informed the flight attendants and passengers of the new flight plan; and prepared for landing into ZZZ. We used maximum forward speed under PIC (Pilot in Command) emergency authority towards ZZZ to minimize passenger and crew exposure to the fumes. We prepared the aircraft for an overweight landing by following the overweight landing QRH procedure and determined we had adequate performance for landing and go-around at our estimated landing weight of around 172700 lbs. We landed uneventfully and taxied to the gate. I made a PA to all passengers to expeditiously deplane the aircraft and to leave bags so they could get off as quickly as possible. For everyone's safety; it was paramount to get everyone off as quickly as possible. We contacted Dispatch about customs concerns but given the nature of the emergency it was not safe to leave anyone on the aircraft for any duration of time. After taking off my mask to exit the aircraft; I noticed the smell was noticeably strong in the cockpit and exited the aircraft expeditiously. The flight attendants were all suffering headaches and were checked out by EMS who met the aircraft.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.