Organophosphates in aircraft cabin air

Abstract

The quality of aircraft cabin air on commercial aircraft has been the subject of adverse press reports for several years. One of the current issues is the potential for aircraft cabin air to become contaminated with organophosphate compounds. The primary compound causing concern is tricresyl phosphate (TCP) and the related decomposition products. It is believed that the contamination is occurring through the bleed air system supplying air to aircraft cabin. Both military and commercial pilots and cabin crew have reported symptoms such as nausea and blurred vision following smoke and fumes leaking from the jet engines and entering into the aircraft cabin. A number of investigations have suggested that the cause of these symptoms was due to the presence of additives in the engine lubricating oils, but as yet no consensus in the conclusions has been reached. The motivation for this research was to understand the problem, to determine if there was potential for air to become contaminated with organophosphate compounds and if the air was to become contaminated, was there sufficient contaminant to cause adverse health issues for cabin crew and passengers.
This research determines the potential levels of organophosphates present in aircraft cabin air. This work aims to experimentally and numerically investigate particle dispersion in aircraft cabins and the associated health risks. Firstly, experimental analysis was undertaken to determine the concentration of organophosphate, in particular TCP in aircraft engine oil and the levels present after pyrolysis. Secondly, mathematical analysis has been conducted to determine the levels of TCP in an aircraft cabin and the potential levels after several hours flight. Thirdly, numerical simulation has been performed to determine the flow paths of particles of within the aircraft cabin.
Chemical analysis has shown that TCP is present in aircraft engine oil in significant levels which would be available to be absorbed into the human body. The mathematical analysis has shown that high levels of TCP will enter the cabin and that short haul and long-haul flights presented a hazard to health. Numerical simulation has shown there would be significant levels of particles within the aircraft cabin, that could be inhaled by occupants or deposited on surfaces which would then accumulate over time.
This research has shown that there are sufficient levels of TCP contaminating aircraft cabin air to cause health issues and that particles will deposit on surfaces in sufficient quantities to cause health issues.
There are a number of recommendations which could reduce the incidences of fume event occurring such as incorporating filters or changing the type of oil used in engines.