Toxicological responses in human airway epithelial cells (BEAS-2B) exposed to particulate matter emissions from gasoline fuels with varying aromatic and ethanol levels

• Published in: The Science of the total environment 2020-03, Vol.706, p.135732, Article 135732
• Main Authors: Ahmed, C.M. Sabbir, Yang, Jiacheng, Chen, Jin Y., Jiang, Huanhuan, Cullen, Cody, Karavalakis, Georgios, Lin, Ying-Hsuan
• Format: Article
• Language: English
• Subjects: Air Pollutants; BEAS-2B; Epithelial Cells; Ethanol; Gasoline; Gasoline composition; Gasoline direct injection; Humans; Oxidative potential; Particulate Matter; Toxicological responses; Vehicle Emissions
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.135732

In this study, we assessed the toxicological potencies of particulate matter (PM) emissions from a modern vehicle equipped with a gasoline direct injection (GDI) engine when operated on eight different fuels with varying aromatic hydrocarbon and ethanol contents. Testing was conducted over the LA92 driving cycle using a chassis dynamometer with a constant volume sampling system, where particles were collected onto Teflon filters. The extracted PM constituents were analyzed for their oxidative potential using the dithiothreitol (DTT) chemical assay and exposure-induced gene expression in human airway epithelial cells (BEAS-2B). Different trends of DTT activities were seen when testing PM samples in 100% aqueous buffer solutions versus elevated fraction of methanol in aqueous buffers (50:50), indicating the effect of solubility of organic PM constituents on the measured oxidative potential. Higher aromatics content in fuels corresponded to higher DTT activities in PM. Exposure to PM exhaust upregulated the expression of HMOX-1, but downregulated the expression of IL-6, TNF-α, CCL5 and NOS2 in BEAS-2B cells. The principal component regression analysis revealed different patterns of correlations. Aromatics content contributed to more significant PAH-mediated IL-6 downregulation, whereas ethanol content was associated with decreased downregulation of IL-6. Our findings highlighted the key role of fuel composition in modulating the toxicological responses to GDI PM emissions. [Display omitted] •Solubility of reactive PM components affects measured aerosol oxidative potential.•Higher aromatic content in fuels corresponded to higher DTT activities in PM.•PM upregulated HMOX-1, and downregulated IL-6, TNF-α, CCL5 and NOS2 in BEAS-2B.•Different correlation patterns identified for aromatic and ethanol content in fuels•Higher ethanol fuel was associated with decreased downregulation of IL-6.