How Clean is Aeroplane Air?

Is the Air on an Aeroplane Clean?

Am I more likely to get sick on a plane?

Is the air in a aeroplane clean?

In short, yes, the air is clean, filtered and safe.

The entire air within the aeroplane cabin is replaced with fresh air approximately every five minutes. The air that is recycled within this time passes through a filter which removes over 99% of bacteria and particles which transport viruses.

How air on a plane works…

The outside air at the plane’s cruise altitude is very cold (as cold as -65°C) and is so thin that it doesn’t hold enough oxygen for humans to breathe. Therefore, an air conditioning system is used to provide air to passenger cabin which ensures a breathable and comfortable cabin environment.

This starts with air entering the engine. Before some of the air goes through the combustion process (mixes with fuel and ignites) within the engine, it is redirected into a ‘bleed’ system. This basically means the air from the engine is bled into various aircraft systems such as the air conditioning and anti-ice systems. This air has been compressed through the initial stages of the engine and therefore it needs to be cooled down.

Once it’s been cooled to the correct temperature, this fresh air which has been compressed, is directed to the recirculation bay where it is mixed with air that has already been through the cabin. Once mixed, it is directed to the aeroplane cabin for passengers to breathe.

The air then disappears under the floor towards the cargo hold. Some of the air is again mixed with the fresh air whilst the rest leaves the aircraft via the ‘outflow valve’ which is normally found at the rear of the aircraft. The amount of air entering the aircraft is a fairly steady rate; it is the amount of air which leaves the aircraft by the outflow valve which dictates the pressurise of the passenger cabin (typically about 6-8psi).

How much of the air is fresh?

It varies from aircraft to aircraft, but a typical ratio is in the region of 60% fresh air to 40% recirculated air. On many aircraft types, the cockpit and therefore the pilots get 100% fresh air.

What filters the aircraft air?

Most aircraft use High-Efficiency Particle Filters (HEPA) to filter the recirculated air. These are the same filters found in hospitals and kill more than 99% of bacteria and stop particles which can carry viruses.

Am I more likely to get ill from being on an aeroplane?

Being on an aeroplane is the equivalent of being in close proximity or being within any enclosed space with lots of people. Think of going to a concert, sporting event or even a busy bar. If you are within close proximity to someone who is ill with something contagious, you are more likely to get. If someone is ill and not sat close to you, you are unlikely to catch it. For example, if someone several rows back from you sneezes, the risk of you catching any illness would be roughly the same as someone sneezing the same distance away from you in a pub or shop. Any contaminated particles would be filtered out by the HERPA filter or dispelled overboard.

So, yes, the risk is higher than if you are sat at home by yourself, but not very different to sitting in the cinema.