How often is the cabin air on an A320 refreshed?

Cabin air on Airbus aircraft is refreshed approximately every two to three minutes during normal operation. That same two-to-three-minute interval holds even without using part of the recirculated air.

Cabin air on Airbus aircraft is a mix of fresh air drawn from outside and recirculated air that has been filtered to remove particles as small as microscopic clusters of bacteria and viruses. The HEPA filters used on Airbus aircraft capture more than 99.9% of microparticles and nanoparticles, viruses, and bacteria. The filters used in aircraft air conditioning are similar to those used in hospitals. Mixing outside air with recirculated air helps make modern passenger aircraft more efficient and reduces fuel consumption. None of the air supplied to the lavatories, galleys, and cargo holds is recirculated into the cabin.

Air conditioning enters the cabin through outlets near the ceiling and exits at floor level. The flow follows a predefined, well-tested pattern: it enters near the ceiling and descends toward the floor. At seat level, there is a constant downward wash of air at 1 m/s.