Association of Lung Function With Benzene, Toluene and Xylene (Btx) in End-exhaled Air in Gas Station Attendants

Abstract

Abstract Background - Gas station attendants are exposed to benzene, toluene and xylenes (BTX) from fuels. The aim was to study the association between this exposure and spirometry parameters in gas station attendants and office workers as controls. Method – In 44 male gas station attendants and 38 office workers in the Gampaha district of Sri Lanka, spirometry was performed according to the guidelines of the American Thoracic Society (ATS). Pre- and postshift end-exhaled air samples were collected from a subgroup of 20 gas station attendants and 11 office workers and analysed for BTX by gas chromatography‒mass spectrometry. Results –The peak expiratory flow rate (PEF) and %-predicted PEF were significantly lower among gas station attendants compared to controls (p = 0.012). Among gas station attendants, the postshift sample benzene level showed a significant negative correlation with %-predicted forced vital capacity (FVC) (Spearman’s correlation coefficient of -0.683, p = 0.014). The %-predicted FVC was lower in gas station attendants working ≥ 5 years compared to those who worked < 5 years (82.71% ±12.53 vs 91.25%±7.50; p = 0.026). In controls, a distinct pattern was observed, indicating a moderate to strong association of postshift toluene and xylenes with all lung function parameters but not benzene. These results were adjusted for smoking. Conclusion –In gas station attendants, we observed restrictive responses in spirometry that were most pronounced for the level of work-related benzene exposure and associated with duration of employment. Air pollutants other than BTX may have contributed to explaining our findings.