Airbus aircraft already offer one of the safest environments with air filtration systems that ensure highest levels of cabin air quality for passengers and crew – thanks to a thoroughly designed cabin “Environment Control System” (ECS). The ECS, which controls and monitors the air quality, temperature and pressure, also ensures that the airflow inside the cabin is constantly moving: It flows from top to bottom at one meter per second, and is subsequently removed through the floor. This airflow is optimised to prevent longitudinal movement, so there is no spread between adjacent seat rows.
In addition, during flight the air is constantly entering and leaving the cabin: As the ‘new’ air enters the cabin from outside, the same quantity of ‘used’ air from the cabin is expelled overboard via the pressurization outflow valves, such that it is fully renewed / exchanged with fresh air about every two to three minutes. For comparison, air in hospital rooms and classrooms is exchanged about every 10 minutes and about 20 minutes in offices.
The fresh air from outside the aircraft is naturally free from any pathogens at the high cruising altitudes where airliners operate. Meanwhile, the other portion of cabin air which is recirculated is first passed through High-Efficiency Particulate Arrestors (HEPA) filters for injection back into the mixer unit in the ECS. HEPA technology, originally developed for the US military to prevent the spread of airborne radioactive contaminants, has been installed in all Airbus aircraft since 1994. The filters, usually installed close to the centre wingbox in the underfloor area of the cabin, are known for their effectiveness in capturing microscopic airborne particulates covering typical bacteria and viruses:
Overall, the HEPA filters eliminate more than 99.9 percent of particles from recirculated air. The result is that the mix of fresh and pre-filtered recirculated air supplied by the ECS to passengers in Airbus cabins is very clean and virus-free.