Net in-cabin emission rates of VOCs and contributions from outside and inside the aircraft cabin

Abstract Volatile organic compounds (VOCs) are one of the most important types of air pollutants in aircraft cabin. Balancing source intensity of VOCs and ventilation strategies is an essential conducive way to obtain acceptable aircraft cabin environment. This paper intends to develop a simplified model by a case study to estimate the net VOC emission rates of cabin interior, and contributions from outside and inside the aircraft cabin. In-flight continuous measurements of total VOCs (TVOC) in cabin air were made in six domestic flights in March 2013. The results indicate that the concentrations of TVOC mostly ranged from 0.20 mg m−3 to 0.40 mg m−3 in cabin air, which first increased at ascent, and then kept elevated during cruise, and decreased at descent in general. For further ventilation information, carbon dioxide (CO2) in supply air and re-circulated air was simultaneously observed as a ventilation tracer to calculate the bleed air ratios, outside airflow rates and total airflow rates in these flights. And thus, the emission rates derived from cabin interior and contributions of TVOC from bleed air and cabin interior were estimated for the whole flight accordingly. Results indicate that during the cruise phase, TVOC in cabin air mainly came from cabin interiors. However, contributions from outside air also became significant during taxiing on the ground, ascent and descent phases. The simplified model would be useful for developing better control strategies of aircraft cabin air quality.