§ Lord Shore of Stepneyasked Her Majesty's Government:
Further to the Written Answer by Lord Whitty on 18 May (WA 28–29) whether government medical advisers believe that in long haul passenger aircraft recycled air is as safe as fresh air with regard to (a) bacterial contamination of healthy passengers; and (b) oxygen level for passengers with respiratory conditions. [HL2596]
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§ Lord WhittyThe Chief Medical Officer of the Civil Aviation Authority believes that the recirculation of air does not pose a risk to the health of passengers.
Even when the air conditioning is set at its lowest level, the air in a modern aircraft cabin is changed every three minutes on average. The oxygen used by passengers is a small proportion, approximately 5 per cent. of the oxygen supplied at the minimum flow rate. The oxygen level in the cabin air therefore remains at around 20 per cent. for the duration of a flight, which is almost the same as normal atmospheric oxygen levels.
There is no evidence of links between cabin air quality, flow rates and the spread of disease. The filters used in most modern aircraft are similar to those used in critical wards of hospitals, operating theatres and burns units, and provide protection against the circulation of biological agents such as viruses. However, the spread of disease is facilitated when large numbers of people gather in close proximity. This has nothing to do with air quality but is a matter of personal contact.
While the re-circulation of air poses no risk, the air pressure in aircraft in flight, which is roughly equivalent to the atmospheric pressure at 8,000 feet above sea level, can affect people with respiratory diseases such as bronchitis, emphysema and bronchiolitis. Those affected are advised to consult their own doctor and the airline before travelling.