Combusting vegetable oils in diesel engines: the impact of unsaturated fatty acids on particle emissions and mutagenic effects of the exhaust

Abstract

High particle emissions and strong mutagenic effects were observed after combustion of vegetable oil in diesel engines. This study tested the hypothesis that these results are affected by the amount of unsaturated or polyunsaturated fatty acids of vegetable oils. Four different vegetable oils (coconut oil, CO; linseed oil, LO; palm tree oil, PO; and rapeseed oil, RO) and common diesel fuel (DF) were combusted in a heavy-duty diesel engine. The exhausts were investigated for particle emissions and mutagenic effects in direct comparison with emissions of DF. The engine was operated using the European Stationary Cycle. Particle masses were measured gravimetrically while mutagenicity was determined using the bacterial reverse mutation assay with tester strains TA98 and TA100. Combustion of LO caused the largest amount of total particulate matter (TPM). In comparison with DF, it particularly raised the soluble organic fraction (SOF). RO presented second highest TPM and SOF, followed by CO and PO, which were scarcely above DF. RO revealed the highest number of mutations of the vegetable oils closely followed by LO. PO was less mutagenic, but still induced stronger effects than DF. While TPM and SOF were strongly correlated with the content of polyunsaturated fatty acids in the vegetable oils, mutagenicity had a significant correlation with the amount of total unsaturated fatty acids. This study supports the hypothesis that numbers of double bounds in unsaturated fatty acids of vegetable oils combusted in diesel engines influence the amount of emitted particles and the mutagenicity of the exhaust. Further investigations have to elucidate the causal relationship.

Gas Emissions and Mutagenic Effects of Diesel and Biodiesel Fuels

“…Some reports showed that the diesel fuel (DF) is significantly higher when compared to BDF exhaust emission. On the other hand, BDF has shown a higher mutagenic potential in the Salmonella assay than DF in the some literatures [11][12].…”

Prediction of Proinflammatory Potentials of Engine Exhausts by Integrating Chemical and Biological Features

“…In fact, the biological interactions of chemical components can also be antagonistic or synergistic. To fill the data gaps, Ames test [11] are routinely utilized to experimentally determine the genotoxicity of engine exhausts providing an overall genotoxicity of mixtures [12][13][14].…”

The response of human bronchial epithelial cells to outdoor air pollution: Interventions to protect the diseased lung against diesel emission exposure

“…Coconut-biodiesel, a common biodiesel in Asia, is cost effective, has close properties to diesel and is globally available [63,64]. Combustion of coconut oil biodiesel has been shown to decrease CO, hydrocarbon content, polycyclic aromatic hydrocarbon (PAH) and decrease total PM from diesel emissions [63,65]. Another strategy to reduce diesel particulate matter is to use a fuel additive to improve the combustio n and energy efficiency of biodiesel [102].…”

“…Biodiesel and fuel additives are emerging interventions to address increasing fuel consumptio n, global warming and the adverse effect of fossil fuels [62]. Research has shown that coconut oil biodiesel can reduce mutagenicity of diesel emissions [65]. However, very little is known about the potential health effect of coconut oil biodiesel and triacetin as a fuel addictive to biodiesel.…”

“…These biodiesels are added to diesel fuel in order to reduce greenhouse gas emissions and preserve fossil fuel resources [63,64]. Biodiesel supplementation has also been shown to reduce diesel particulate matter pollution [63,65] [61]. Fuel additives includ ing triacetin are often added to biodiesels to increase oxygen content of the fuel, improving engine efficiency and further reducing emissions [61,66,67].…”