Cabin air quality - Quantitative comparison of volatile air contaminants at different flight phases during 177 commercial flights

Quantitative assessment of human exposure to semi-volatile organic compounds (SVOC), such as tricresyl phosphates (TCP) that may originate from engine oil contamination of the cabin air, during air travel is challenging due to the technical complexity of the air supply in commercial jet aircraft. Normal flight operations involve reduced air exchange before and during takeoff, which results in increased concentrations of potential cabin air pollutants. During cruise, normal ventilation rates ( > 20 h(-1)) are reestablished and thus lower pollutant concentrations are also reestablished. This relationship between changes in ventilation rate and associated changes in pollutant concentrations during the departure phase is first described in the present study, although this effect was found by previous studies that investigated distinct flight phases. The perception of so-called "smell events" in cabin air does not necessarily indicate the presence of harmful contaminants and TCP-containing oil mist must be clearly distinguished thereof. Thus, aldehydes, VOCs, and organophosphates such as TCP were investigated. In this paper, the occurrence of TCP contamination in a bleed air free Boeing 787 (B787) aircraft is reported for the first time. The results presented here show that there are TCP sources other than bleed air from leaky engines. Furthermore, exceptional release behavior of TCP suggests that a more detailed classification for engine oil-triggered cabin air contamination (CAC) events is necessary. This study evaluated measurement data from 177 flights that were either commissioned by the EASA or conducted as part of studies with the support of Lufthansa, Condor, and British Airways.