Toxicological properties of emission particles from heavy duty engines powered by conventional and bio-based diesel fuels and compressed natural gas

Abstract

BackgroundOne of the major areas for increasing the use of renewable energy is in traffic fuels e.g. bio-based fuels in diesel engines especially in commuter traffic. Exhaust emissions from fossil diesel fuelled engines are known to cause adverse effects on human health, but there is very limited information available on how the new renewable fuels may change the harmfulness of the emissions, especially particles (PM). We evaluated the PM emissions from a heavy-duty EURO IV diesel engine powered by three different fuels; the toxicological properties of the emitted PM were investigated. Conventional diesel fuel (EN590) and two biodiesels were used − rapeseed methyl ester (RME, EN14214) and hydrotreated vegetable oil (HVO) either as such or as 30% blends with EN590. EN590 and 100% HVO were also operated with or without an oxidative catalyst (DOC + POC). A bus powered by compressed natural gas (CNG) was included for comparison with the liquid fuels. However, the results from CNG powered bus cannot be directly compared to the other situations in this study.ResultsHigh volume PM samples were collected on PTFE filters from a constant volume dilution tunnel. The PM mass emission with HVO was smaller and with RME larger than that with EN590, but both biofuels produced lower PAH contents in emission PM. The DOC + POC catalyst greatly reduced the PM emission and PAH content in PM with both HVO and EN590. Dose-dependent TNFα and MIP-2 responses to all PM samples were mostly at the low or moderate level after 24-hour exposure in a mouse macrophage cell line RAW 264.7. Emission PM from situations with the smallest mass emissions (HVO + cat and CNG) displayed the strongest potency in MIP-2 production. The catalyst slightly decreased the PM-induced TNFα responses and somewhat increased the MIP-2 responses with HVO fuel. Emission PM with EN590 and with 30% HVO blended in EN590 induced the strongest genotoxic responses, which were significantly greater than those with EN590 + cat or 100% HVO. The emission PM sample from the CNG bus possessed the weakest genotoxic potency but had the strongest oxidative potency of all the fuel and catalyst combinations. The use of 100% HVO fuel had slightly weaker and 100% RME somewhat stronger emission PM induced ROS production, when compared to EN590.ConclusionsThe harmfulness of the exhaust emissions from vehicle engines cannot be determined merely on basis of the emitted PM mass. The study conditions and the engine type significantly affect the toxicity of the emitted particles. The selected fuels and DOC + POC catalyst affected the PM emission from the heavy EURO IV engine both qualitative and quantitative ways, which influenced their toxicological characteristics. The plain HVO fuel performed very well in emission reduction and in lowering the overall toxicity of emitted PM, but the 30% blend of HVO in EN590 was no better in this respect than the plain EN590. The HVO with a DOC + POC catalyst in the EURO IV engine, performed best with regard to changes in exhaust emissions. However some of t...

Particulate matter characteristics, dynamics, and sources in an underground mine

“…Besides efficient ventilation, that should be mandatory in all enclosed spaces with emissions, it is important to decrease the emissions through better engine technologies, higher fuel quality, and advanced after-treatment techniques. However, it should be noted that the introduction of novel engine and exhaust after-treatment technologies into vehicles used in underground mines may change not only the quantity but also the physico-chemical characteristics and toxic properties of emissions (Murtonen et al 2010;Jalava et al 2012). In this study, a 3 day experiment was conducted when fossil diesel fuel was changed to 100% renewable diesel fuel in all the vehicles in the underground mine.…”

In vitro Evaluation of Oxidative Stress Caused by Fine Particles (PM2.5) Exhausted from Heavy-Duty Vehicles Using Diesel/Biodiesel Blends under Real World Conditions

“…In spite of the fact there have been recent efforts to better understand diesel/biodiesel emitted particles toxicity, 4,5,16,23 several studies consider samples collected on dynamometers, which facilitates to run repeatable experiments and subsequent studies. However, in these experiments it is not taken into account the differences in the driving cycle or engine technology under typical daily commuting around urban regions.…”

“…Inhalation of diesel-emitted particles, mainly in the fine particulate fraction, is a matter of significant concern [1][2][3] since both environmental and occupational exposures to diesel exhaust particles (DEP) are considerable 1,2 and may lead to diverse health-related endpoints, such as cancer and pulmonary or respiratory disorders, [2][3][4][5][6][7] as well as morbidity and mortality. 8,9 When also considering premature deaths according to inhalation of fine particles in outdoor environments, there were 3.3 million deaths worldwide in 2010 and it is estimated to be more than 6.5 million premature deaths by 2050.…”

“…However, it is still uncertain if biodiesel-exhausted particles (BEP) would be more or less toxic than DEP. Despite the fact some studies have tried to address this issue, 4,16,17,23,24 the toxicity of traffic-related urban PM is still not completely understood and more studies are needed.…”

“…24,25 For instance, some transition metals (such as Fe and Cu) and organic species (e.g. polycyclic aromatic compounds and quinones or quinone-like compounds) as well as humic-like substances (HULIS), black and brown carbon (BC and BrC) within PM are known to increase the production of ROS either in vitro or in vivo, especially if they are present in fine and ultrafine size range, [4][5][6]24,[30][31][32][33][34][35] since they are able to go more profoundly in the respiratory system. Meanwhile, considering diesel/biodiesel blends exhausts are substantially composed by ever small size PM, such as nanoparticles and/or ultrafine particles rich in semi-volatile organic compounds and trace metals, 1,7,16 it is likely ROS may be contributing to the adverse health effects caused by DEP or even BEP.…”