Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft
Climbing out of ZZZ the Captain and I noticed a fume smell that did not dissipate. The Captain called the Flight Attendants and they also reported the smell and that they had headaches; irritated eyes and throats. Several passengers also noticed the fumes; which appeared to be stronger in the cabin. We ran the appropriate checklist and got ATC clearance to return to ZZZ. We made an overweight but uneventful landing on Runway XXR. CFR (Crash Fire Rescue) and EMS met the aircraft and the affected passengers and cabin crew were offered appropriate care. Neither Captain or FO (First Officer) had any symptoms and at no time was any smoke or fire observed by anyone.The cause of the fumes remains undetermined.
Air carrier First Officer reported an air return due to fumes in the aircraft.