Ultrafine particles and black carbon concentrations and determinants in aircraft cabins of a French airline: Paris-aircraft study

People are spending increasing amounts of time on airplanes. Nevertheless, few studies have characterized the concentrations of ultrafine particles (UFP) and black carbon (BC) in aircraft cabins, which are particulate pollutants known to have adverse health effects. This study aims to assess indoor air quality by measuring UFP and BC concentrations in aircraft cabins during different phases of flight and identifying the key determinants influencing their levels. This study reports pollutant concentrations measured from the beginning of boarding to the end of disembarkation across 16 European commercial flights conducted on three aircraft types (A220, A319, A321). A phase-by-phase multivariate regression analysis was performed to identify the factors associated to these concentration levels. Average concentrations of 9,122 particles/cm³ for UFP and 207 ng/m³ for BC were observed. Ground phases showed higher concentrations than in-flight phases, with levels decreasing after take-off and increasing again during descent (UFP) and after landing (UFP and BC). The analyses of determinants revealed: (1) a decrease in UFP levels with longer cruise duration; (2) an increase in both UFP and BC levels during extended taxiing; (3) higher BC levels with a greater number of passengers; (4) specific aircraft types elevated UFP levels during climb and descent; (5) a lack of association with altitude, turbulence events, or duration of meal service. Measured levels showed much lower concentrations of these pollutants compared to other modes of transport. Cabin concentrations of UFP and BC appeared to be primarily driven by outdoor sources, particularly those related to airport ambient air pollution.