Question to the Department for Transport:

To ask Her Majesty's Government whether there is any scientific evidence that proves that filters in planes and air conditioning units prevent COVID-19 particles from passing through.

Onboard commercial aircraft, cabin air is pre-filtered through High Efficiency Particulate Air (HEPA) filters before being mixed with fresh air from outside the aircraft and returned back to the cabin. Airbus claim that “The result is that the mix of fresh and pre-filtered recirculated air supplied by the Environment Control System to passengers in Airbus cabins is very clean and virus-free."

Research published by NASA has looked at the efficiency of HEPA filters, such as those present on Airbus and Boeing aircraft. This research supports Airbus’ claim, showing that HEPA filters have capture efficiencies >99.9% for particles of a similar size to that of the COVID-19 virus.

We are planning new research which aims to understand the effect air re-circulation systems have on the transmission of COVID-19 aboard passenger aircraft.

It is important to note that filters within standard air conditioning units may not be HEPA filters and therefore many not offer the same level of protection, and that air filtration alone will not stop all possible routes of COVID-19 transmission.