Understandably many travellers are concerned about boarding an aircraft under the current threat of the COVID-19 circumstances. As a step towards regaining customer confidence and as a kick start for travel, the British Airline Pilots’ Association have put together the following information concerning COVID-19 and cabin air.
“It is a common misconception amongst passengers that when on board a flight, they are all sharing ‘stale air’. At this time, with coronavirus a real fear amongst the public, it is more important than ever to challenge that misconception and help the public understand the way cabin air works.
Where does the air come from and how does it flow?
Cabin air is a mix of fresh air drawn from outside of the aircraft (treated prior to entering the cabin so that it is at a pressure and temperature comfortable for breathing) and existing cabin air that has been recycled through extremely efficient filters (known as High Efficiency Particulate Air (HEPA) filters) that are capable of trapping microscopic-sized particles such as SARS-Cov-2 (the novel coronavirus which causes Covid-19). Tests have shown HEPA filters to have an efficiency level of better than 99.99% and they provide air that meets the standards set for hospital operating theatres. In normal operation, less than half of the air is filtered and recirculated, the rest is fresh air drawn in from outside the aircraft.
Air supplied to the cabin enters at the level of the overhead compartments (from above and below them) and is extracted at floor level. This means that the air is drawn down and, importantly, there is no flow forward or aft along the cabin. Air supplied to aircraft toilets, galleys and cargo-holds is not filtered, but instead is dumped directly overboard. The cabin air in a typical airliner aircraft such as an Airbus A320 is completely changed, on average, every three minutes, which compares to every 10-12 minutes in a typical air-conditioned building.”