Date: 202101
Local time of day: 1201-1800
Location: ZZZ.TRACON, US
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Aircraft component: Coalescer Bag
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Other / Unknown; Physiological - Other
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Flight Deck / Cabin / Aircraft Event Illness / Injury
Detector: Person Flight Crew; Person Flight Attendant
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Overcame Equipment Problem; Flight Crew Landed in Emergency Condition; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: My first attempt at writing this portion did not save so I will attempt it again. We had an A321 sharklet. Every portion of the beginning of the flight leg from gate departure; takeoff and climb up to the fume event was normal and routine. At sometime above 10;000 ft. we got a call from our #1 FA (Flight Attendant) telling us that the FAs in Economy Class more towards the rear of the aircraft were smelling a sweat odor and a more robust glue type odor. I believe from my prospective that the odor came from the back from the wings black wards because we did not smell anything in the flight deck and no one smelled anything in first class; #1 FA or forward section of the cabin behind 1st class section. Captain began trouble shooting the problem with the QRH guidelines and the FAs that was smelling the odors. One of the FAs was feeling ill from the fume which was strong in the area they were working. Passenger in that area smelled the odors as well. Captain asked if she can continue or do we need to get back to the gate in ZZZ so she can seek medical attention. She was not sure if she wanted to continue on toward ZZZZ1 or return. Captain asked the #1 FA to monitor the FA's condition and if she worsened we will return to ZZZ. While we were discussing the QRH fume trouble shooting pages and making plans to return to ZZZ or another airport that may be closer to our position if we continued to fly farther away from ZZZ; the #1 FA called and told us the FA that was feeling ill was on O2 and was not getting better. So we notified ATC that we will be returning to ZZZ which was the best option to land. We [were given priority handling] to expedite our return to ZZZ and so the FA can get the medical attention she needed. As we began to descend into ZZZ I remember it was below FL180 and through landing that the odors began to infiltrate the flight deck and the #1 FA and passengers began smelling it too. We donned our O2 masks. It was a sweaty smell and it also had an Elmer's glue order to us. The odors continued until we arrived to the gate. The FA that was really ill went to the hospital and the remaining flight crew continued with us to ZZZZ1 with a replacement FA.I don't know of any causal factors that would cause a fume event other than fixing the problem of the source that caused the fumes from escaping and preventing and future leaks from going into the cabin.The only thing that would prevent this from happening would be a complete redesign of the airplane systems that keeps the cabin ventilation isolated from any possible fume leaking into the cabin.




Synopsis: A321 First Officer reported a fumes event during departure climb resulting in a return to the departure airport.