Emissions from a flex fuel GDI vehicle operating on ethanol fuels show marked contrasts in chemical, physical and toxicological characteristics as a function of ethanol content

Jiacheng Yang; Patrick Roth; Thomas D Durbin; Martin M Shafer; Jocelyn Hemming; Dagmara S Antkiewicz; Akua Asa-Awuku; Georgios Karavalakis

doi:10.1016/j.scitotenv.2019.05.279

Emissions from a flex fuel GDI vehicle operating on ethanol fuels show marked contrasts in chemical, physical and toxicological characteristics as a function of ethanol content

Sci Total Environ. 2019 Sep 15:683:749-761. doi: 10.1016/j.scitotenv.2019.05.279. Epub 2019 May 23.

Authors

Jiacheng Yang¹, Patrick Roth¹, Thomas D Durbin¹, Martin M Shafer², Jocelyn Hemming³, Dagmara S Antkiewicz³, Akua Asa-Awuku⁴, Georgios Karavalakis⁵

Affiliations

¹ Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA; Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), Riverside, CA 92507, USA.
² Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, USA; Wisconsin State Laboratory of Hygiene, University of Wisconsin-Madison, Madison, WI, USA.
³ Wisconsin State Laboratory of Hygiene, University of Wisconsin-Madison, Madison, WI, USA.
⁴ Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA; Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), Riverside, CA 92507, USA; Department of Chemical and Biomolecular Engineering, A. James Clark School of Engineering, University of Maryland, College Park, MD 20742, USA.
⁵ Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA; Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), Riverside, CA 92507, USA. Electronic address: gkaraval@cert.ucr.edu.

PMID: 31150895
DOI: 10.1016/j.scitotenv.2019.05.279

Abstract

This study assessed the gaseous and particulate emissions, as well as the toxicological properties of particulate matter (PM) from a flex fuel vehicle equipped with a wall-guided gasoline direct injection engine over triplicates cold-start and hot-start LA92 cycles. The vehicle was operated on a Tier 3 E10 fuel, an E10 fuel with higher levels of aromatics than the Tier 3 E10, an E30, and an E78 blend. Total hydrocarbon (THC), non-methane hydrocarbon (NMHC), carbon monoxide (CO), particulate emissions, and gaseous toxics (of benzene, toluene, ethylbenzene, xylenes (BTEX), and 1,3-butadiene) reduced for E30 and E78 blends compared to both E10 fuels. Formaldehyde and acetaldehyde emissions substantially increased with the higher ethanol blends. The high aromatic E10 fuel increased the emissions of THC, NMHC, particulates, and BTEX compared to the Tier 3 E10 fuel and the higher ethanol blends, as well as showed higher concentrations of accumulation mode particles. The GDI PM did not exhibit any measurable mutagenicity at the PM concentrations tested. Cytotoxicity varied only within a small range and concentrations of PM, eliciting a cytotoxic response similar to those by ambient aerosol. The outcomes of our two measures of PM oxidative potential (macrophage ROS and DTT) were significantly correlated, with the E78 blend exhibiting the least oxidative potential and the E30 the greatest. Gene expression analysis at both the mRNA and protein level indicates that there is the potential for GDI PM emissions to contribute to inflammation and etiology of disease such as asthma, and in contrast to the ROS and DTT outcomes, the E78 fuel PM exhibited the greatest potential to elicit pro-inflammatory cytokine (TNFα) production. Overall, the trends in toxicity emission rates (activity/mi) across the ethanol blends was driven primarily by PM mass emission rate contrasts and only secondarily by the differences in intrinsic toxicity of the PM.

Keywords: Ethanol blends; Gasoline direct injection; Oxidative stress; PM emissions; PM toxicity; Toxic pollutants.

MeSH terms

Air Pollutants / analysis*
Ethanol / analysis*
Gasoline / analysis
Vehicle Emissions / analysis*

Substances

Air Pollutants
Gasoline
Vehicle Emissions
Ethanol