A319
Flight Crew Air Transport Pilot (ATP)
Physiological - Other
Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Physical Injury / Incapacitation
Aircraft
On initial climb; the Captain noted a very slight scent in the flight deck. I personally couldn't tell anything different from standard. He noted shortly after (possibly through transition) that the scent was no longer present. During cruise; we both reviewed the smoke and fumes checklist in the QRH just in case anything further were to occur. Initial descent was normal. Through approximately 15;000 MSL; the Captain noted the smell once again; at this time; I certainly could smell the same scent. Although there was no visible smoke/fumes; the smell was considerable. The flight attendants called prior to sterile to advise us that the odor was very apparent in the cabin both forward and aft. They likened it to a sock smell; but to me it didn't seem so. It's a difficult smell to explain; certainly an acrid almost oily; plastic melting type of smell. We continued the approach to a normal landing. The APU was not running at the time of the event but was started during the after landing checklist. Upon landing the smell was oppressively strong and continued to worsen during the taxi and shut down. Once the aircraft shut down; we communicated again with the FAs who were complaining of nausea. At this point; I had a strong headache and irritated throat. Captain continued to feel worse upon shut down of the aircraft. Exterior walk around didn't show anything that would suggest ingestion of anything that could have caused an issue. All crew went to the emergency room for checks.It's hard for me to suggest a fix other than to possibly run the aircraft and isolate specific parts of the bleed system ideally in flight to get a true sense of what is happening and see which area it is likely coming from.
A319 First Officer reported the entire flight and cabin crew felt physical effects from the fumes and odor of unknown origin in the aircraft.