Fume Events in Aircraft Cabins
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The inlet for ventilation air to the cabin and cockpit is placed in the aircraft engines. The air supply is known as bleed air, which is used on most commercial aircraft. During leakage due to malfunctions in the engines, such as ineffective or damaged seals, the air may be contaminated with constituents like organophosphates and other hazardous chemicals from jet engine oils or hydraulic fluids. This phenomenon is described as a fume event. Media attention regarding the air-quality in aircraft cabins has the latest years increased. Flight crew and passengers have reported symptoms and negative health effects assumed to be associated with exposure to contaminated bleed air. The aim of the study was to find out what is known about the nature of fume events, and its attention among flight crew and a sample of people on Gløshaugen campus. In addition, it was desirable to clarify the severity and estimate the frequency of such events. A literature study was conducted to examine the technical background and characteristics of a bleed air system, the phenomenon of fume events, and possible health impacts following these events. Surveys were distributed to a selected group of flight crew and a sample of people on Gløshaugen campus, to clarify if they acknowledge the extent of fume events. An overview of possible fume events between January 2007 and December 2014 was compiled by the use of different databases and news articles. The response rate of the survey among pilots and cabin crew was 21 %. The results from the survey showed that 70.5 % of the 624 respondents were familiar with fume events, while 43.6 % considered air contamination a problem in the aircraft industry. The response rate of the survey among people on Gløshaugen campus was 94.3 %. Of the 100 respondents, 85 % had not heard about such events, while 6 % had noticed an unusual smell or smoke in the cabin. There were found 701 possible fume events, which resulted in an estimated frequency of 0.24 events per day. Researchers have attempted to find whether there exists any connection between reported health effects and fume events. Fume events have not been manifested by measurements or sampling of contaminated air during an event, but it is assumed that aircraft occupants can be exposed to a chemical cocktail of contaminants. Some of these chemicals are known to cause symptoms and adverse health effects. The general knowledge about fume events among flight crew is considered relatively good. Although the number of respondents in the survey among people on Gløshaugen campus is low, the results indicate that academics have less knowledge and attention about fume events than flight crew. Compared to other results from previous studies, the estimated frequency of such events is low. However, oil leakage episodes are known to be underreported due to variations in thresholds by flight crew to report an event, as well as subjective assessment of the air-quality. Further research is necessary to clarify whether the reported negative health effects can be explained by fume events. The air-quality in aircraft needs to be measured by the use of incident samplers. These should be placed in all aircraft to continuously measure the concentrations of contaminants entering the cabin and cockpit during a fume event. If the general population acquire better knowledge about fume events, the aircraft industry may be willing to implement mitigating measures to prevent such events, given that they are proven to cause the reported health impacts.