Ultrafine Particles Issued from Gasoline-Fuels and Biofuel Surrogates Combustion: A Comparative Study of the Physicochemical and In Vitro Toxicological Effects

Abstract

Gasoline emissions contain high levels of pollutants, including particulate matter (PM), which are associated with several health outcomes. Moreover, due to the depletion of fossil fuels, biofuels represent an attractive alternative, particularly second-generation biofuels (B2G) derived from lignocellulosic biomass. Unfortunately, compared to the abundant literature on diesel and gasoline emissions, relatively few studies are devoted to alternative fuels and their health effects. This study aimed to compare the adverse effects of gasoline and B2G emissions on human bronchial epithelial cells. We characterized the emissions generated by propane combustion (CAST1), gasoline Surrogate, and B2G consisting of Surrogate blended with anisole (10%) (S+10A) or ethanol (10%) (S+10E). To study the cellular effects, BEAS-2B cells were cultured at air-liquid interface for seven days and exposed to different emissions. Cell viability, oxidative stress, inflammation, and xenobiotic metabolism were measured. mRNA expression analysis was significantly modified by the Surrogate S+10A and S+10E emissions, especially CYP1A1 and CYP1B1. Inflammation markers, IL-6 and IL-8, were mainly downregulated doubtless due to the PAHs content on PM. Overall, these results demonstrated that ultrafine particles generated from biofuels Surrogates had a toxic effect at least similar to that observed with a gasoline substitute (Surrogate), involving probably different toxicity pathways.

Zero-Carbon and Carbon-Neutral Fuels: A Review of Combustion Products and Cytotoxicity

“…BEAS-2B cells exhibit cytotoxicity and DTT activity (oxidative potential) and develop oxidative stress (HMOX-1 gene expression upregulation) after exposure to pure HVO and HVO-biodiesel blend PM emissions [187]. Another study also observed that BEAS-2B cells exhibited mild cytotoxicity associated with alterations in ATP/ADP ratios, increased expression of oxidative stress marker genes (NQO1 and HO-1), inflammatory marker genes (IL-8 and IL-6), and xenobiotic metabolic marker genes (CYP1A1 and CYP1B1) after 3 h of exposure to second-generation biofuel (B2G) extracted from lignocellulosic biomass [188]. Betha et al also noted that biodiesel (B100) from waste cooking oil (WCO) caused higher cytotoxicity and oxidative stress in A549 cells than ULSD [173].…”