Cabin Air Quality: A review of current aviation medical understanding

Concerns continue to be expressed about cabin air quality and perceived effects on health; this is a review of the current aviation medical understanding. Cabin Pressurisation Atmospheric pressure reduces with altitude, but normal people can tolerate a reduction in oxygen partial pressure up to around 10,000ft; above this, oxygen partial pressure reduces rapidly and impairs brain function. To provide a buffer for those not fully fit, the maximum certified cabin altitude in normal operation is 8,000ft. During flight, air is derived from the compression stage of the jet engine or, in the case of the B787, from electrically driven compressors. This bleed air is conditioned and filtered, with an exchange of 10-15 times per hour with outside air and 20-30 times per hour including outside and filtered recirculated air