Bioethanol Blending Reduces Nanoparticle, PAH, and Alkyl- and Nitro-PAH Emissions and the Genotoxic Potential of Exhaust from a Gasoline Direct Injection Flex-Fuel Vehicle

Abstract

Bioethanol as an alternative fuel is widely used as a substitute for gasoline and also in gasoline direct injection (GDI) vehicles, which are quickly replacing traditional port-fuel injection (PFI) vehicles. Better fuel efficiency and increased engine power are reported advantages of GDI vehicles. However, increased emissions of soot-like nanoparticles are also associated with GDI technology with yet unknown health impacts. In this study, we compare emissions of a flex-fuel Euro-5 GDI vehicle operated with gasoline (E0) and two ethanol/gasoline blends (E10 and E85) under transient and steady driving conditions and report effects on particle, polycyclic aromatic hydrocarbon (PAH), and alkyl- and nitro-PAH emissions and assess their genotoxic potential. Particle number emissions when operating the vehicle in the hWLTC (hot started worldwide harmonized light-duty vehicle test cycle) with E10 and E85 were lowered by 97 and 96% compared with that of E0. CO emissions dropped by 81 and 87%, while CO emissions were reduced by 13 and 17%. Emissions of selected PAHs were lowered by 67-96% with E10 and by 82-96% with E85, and the genotoxic potentials dropped by 72 and 83%, respectively. Ethanol blending appears to reduce genotoxic emissions on this specific flex-fuel GDI vehicle; however, other GDI vehicle types should be analyzed.

Toxicological evaluation of exhaust emissions from light-duty vehicles using different fuel alternatives in sub-freezing conditions

“…Concerning the gasoline-fuelled cars, the present study indicates that that using high-concentration ethanol fuel in FFV reduces the PAH and PM mass concentrations, and toxicity of the exhaust PM, when compared to gasoline car. Similar results have been observed in the previous studies [40,54,71]. However, since the exhaust gas PN emissions from gasoline powered cars were considerably high compared to Euro 6 diesel and CNGpowered cars, one possibility for reducing PM emissions would be the implementation of the gasoline particle filters (GFP) which have been shown to reduce PM mass and PN emissions also in cold running temperatures [30] and decrease the toxicity of the gasoline exhaust [63].…”

“…Moreover, DTT and DCF assays indicate that exhaust PM from E85 fuelled passenger car had no notable acellular oxidative potential nor ability to induce intracellular oxidative stress. Indeed, previous studies have demonstrated that E85 PM has lower oxidative DNA damage potential and reduced concentrations of genotoxic PAH compounds compared to the gasoline exhaust PM [40]. Interestingly, mutagenicity assayed by microAmes test displayed multi-fold mutagenic potential when S9 was included in the assay.…”

“…So far studies have shown that compressed natural gas (CNG) fuelled cars equipped with three-way catalyst (TWC) result to very low particle number emissions [1], and PM emissions from CNG fuelled cars have been associated with lower concentrations of PMbound carcinogenic PAHs, compared to gasoline and diesel cars [7]. Additionally, the higher ethanol blend in gasoline has been detected to result in lower PM emissions in exhaust gases with less toxicologically active PAH compounds [40,71], which have also been observed at sub-freezing ambient temperatures [2,54]. Hence, the running and starting conditions influence the emissions in addition to differences in fuels.…”

Gasoline particle filter reduces oxidative DNA damage in bronchial epithelial cells after whole gasoline exhaust exposure in vitro

“…Given that a scanning mobility particle sizer, as we used it for the measurement of the particle-size distribution, requires minutes to scan the particle number size distribution, we were not able to measure the particle size distribution during the WLTC due to the rapidly changing velocity pattern. Instead, we used data from another project 47 , in which emissions from the same car equipped with or without the same GPF were characterized driving the SSC. While the peak of the particle diameter without GPF was approximately 69 nm, the peak of the particle diameter with GPF was about 113 nm, likely indicating an agglomeration of particles due to the GPF or higher filtration efficiency for smaller particles compared to bigger ones.…”

Fuel Effects on Particulate Matter Emissions Variability from a Gasoline Direct Injection Engine

“…He et al [9] also saw very little in terms of difference at the E0 and E10 levels, though at E20 reductions were evident. Munoz et al [10] found that increasing ethanol content in gasoline from 0 to 10% and then 85% resulted in decreased PN and PAH concentrations, with most of the change occurring from 0-10% and less from 10-85%. The effect was most pronounced under transient conditions.…”