Determination of eight benzene homologues in airport ambient air and aircraft cabin air by two-stage thermal desorption-gas chromatography

Abstract

In this study, a two-stage thermal desorption-gas chromatography (TTD-GC) method was established to determine eight benzene homologues (benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, styrene, and p-tert-butyltoluene) in airport ambient air and aircraft cabin air. By optimizing chromatographic conditions and two-stage thermal desorption parameters, detection sensitivity was significantly enhanced. The detection limits for the eight benzene homologues ranged from 41 ng m⁻³ to 108 ng m⁻³, achieving sub-nanogram-level sensitivity, which enabled effective detection of low-concentration benzene homologues. The results demonstrated that the method was highly suitable for complex environmental samples, enabling effective separation and detection of the eight benzene homologues without interference from multiple substances in airport ambient air or other organic compounds released from cabin materials. Furthermore, the integrated design of sample pretreatment and analysis minimizes the steps for sample pretreatment, eliminating errors arising from sample transfer and solvent extraction in conventional methods. This has consequently improved the detection efficiency and accuracy. The spiked recoveries of the method were between 90.5% and 115.2%, with relative standard deviations ranging from 0.6% to 8.1%. Short-term monitoring of airport ambient air and aircraft cabin air revealed that benzene homologues concentrations significantly increased during airport peak flight hours and the initial stage of aircraft takeoff, and gradually decreased during the flight. Based on concentration ratios and correlation analyses, we inferred that airport ambient air homologues primarily originated from aviation fuel combustion and ground transportation exhaust, while cabin air homologues stemmed from interior material volatilization, outdoor air circulation/recirculation, and fuel vapor permeation. This study presents a novel technical approach for airport and cabin air quality monitoring, providing scientific evidence for relevant environmental management and health risk assessments.