Mitigation of PAH and Nitro-PAH Emissions from Nonroad Diesel Engines

Liu, Z. Gerald; Wall, John C.; Ottinger, Nathan; McGuffin, Dana L.

doi:10.1021/es505434r

Cited by 22 publications

(23 citation statements)

References 32 publications

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“…7). The average ratios of the PAHs in excavator exhaust obtained in this study are similar to those reported by Liu et al (2015). The E4 excavator showed obvious differences in the ratios of BaA / (BaA +vChry), IcdP / (IcdP + BghiP), and Flua / (Flua + Pry) from those for the other excavators.…”

Section: Particulate Matter Composition For Individual Excavatorsupporting

confidence: 87%

Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

et al. 2017

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Abstract. With the rapid growth in the number of both non-road and on-road diesel vehicles, the adverse effects of particulate matter (PM) and its constituents on air quality and human health have attracted increasing attentions. However, studies on the characteristics of PM and its composition emitted from diesel vehicles are still scarce, especially under real-world driving conditions. In this study, six excavators and five trucks that provided a wide range of emission standards and operation modes were tested, and PM emissions and their constituents -including organic carbon (OC), elemental carbon (EC), water-soluble ions (WSIs), elements, and organic species like polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and hopanes -as well as steranes were analyzed and characterized. The average emission factors for PM (EF PM ) from excavator and truck emissions were 829 ± 806 and 498 ± 234 mg kg −1 fuel, respectively. EF PM and PM constituents were significantly affected by fuel quality, operational mode, and emission standards. A significant correlation (R 2 = 0.79, p < 0.01) was found between EF PM for excavators and the sulfur contents in fuel. The highest average EF PM for working excavators was 904 ± 979 mg kg −1 fuel as a higher engine load required in this mode. From pre-stage 1 to stage 2, the average EF PM for excavators decreased by 58 %. For trucks, the average nonhighway EF PM at 548 ± 311 mg kg −1 fuel was higher than the highway EF PM at 497 ± 231 mg kg −1 fuel. Moreover, the reduction rates were 63.5 and 65.6 % when switched from China II and III to China IV standards, respectively. Generally, the PM composition emitted from excavators was dominated by OC (39.2 ± 21.0 %) and EC (33.3 ± 25.9 %); PM from trucks was dominated by EC (26.9 ± 20.8 %), OC (9.89 ± 12 %), and WSIs (4.67 ± 5.74 %). The average OC / EC ratios for idling and working excavators were 3 to 4 times higher than those for moving excavators. Although the EF PM for excavators and trucks was reduced with the constraint of regulations, the element fractions for excavators increased from 0.49 % in pre-stage 1 to 3.03 % in stage 2, and the fraction of WSIs for the China IV truck was 5 times higher than the average value of all other-level trucks. Furthermore, as compared with other diesel vehicles, wide ranges were found for excavators of the ratios of benzo operation modes. A comparison of our results with those in the literature revealed that on-board measurement data more accurately reflect actual conditions. Although the fractions of the 16 priority PAHs in PM from the excavator and truck emissions were similar, the equivalent concentrations of total benzo[a]pyrene of excavators were 31 times than that for trucks, implying that more attention should be paid to non-road vehicle emissions.

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Section: Particulate Matter Composition For Individual Excavatorsupporting

confidence: 87%

Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

et al. 2017

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“…The formation mechanism of Nitro-PAHs through the nitration reaction during the combustion process in the cylinder has been investigated by several researches. Nevertheless, the knowledge about this process remains inconclusive (Kielhorn et al, 2003;Heeb et al, 2008;Liu et al, 2015). During the combustion, Nitro-PAHs can be formed by electrophilic substitution reactions in the presence of NO x and the combination of high temperatures.…”

Section: Particle-phase Nitro-pahsmentioning

confidence: 99%

“…In a recent study, Liu et al (2015) examined the emission of Nitro-PAHs using various types of aftertreatment systems in different configurations. When testing DOC + SCR, the emissions of PAHs increased compared to the results of the engine without any after-treatment system.…”

Section: Particle-phase Nitro-pahsmentioning

confidence: 99%

“…When testing DOC + SCR, the emissions of PAHs increased compared to the results of the engine without any after-treatment system. When studying only the SCR system, a reduction in the emission of Nitro-HPAs was observed by Liu et al (2015). However, the authors also concluded that the formation of Nitro-PAHs by the SCR system is questionable, since this system significantly reduces NO 2 concentrations, decreasing their availability for the conversion of PAHs into their nitrated forms.…”

Section: Particle-phase Nitro-pahsmentioning

confidence: 99%

“…The best reported SCR efficiency is achieved at high engine loads and temperatures (approximately 400°C) (Cheruiyot et al, 2017). However, the added urea increases the probability of unintended formation of Nitro-PAHs through PAHs nitration (Liu et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Polycyclic Aromatic Hydrocarbons (PAHs) and nitrated analogs associated to particulate matter emission from a Euro V-SCR engine fuelled with diesel/biodiesel blends

Borillo

Tadano

Godoi

et al. 2018

Science of The Total Environment

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Among the new technologies developed for the heavy-duty fleet, the use of Selective Catalytic Reduction (SCR) aftertreatment system in standard Diesel engines associated with biodiesel/diesel mixtures is an alternative in use to control the legislated pollutants emission. Nevertheless, there is an absence of knowledge about the synergic behaviour of these devices and biodiesel blends regarding the emissions of unregulated substances as the Polycyclic Aromatic Hydrocarbons (PAHs) and Nitro-PAHs, both recognized for their carcinogenic and mutagenic effects on humans. Therefore, the goal of this study is the quantification of PAHs and Nitro-PAHs present to total particulate matter (PM) emitted from the Euro V engine fuelled with ultra-low sulphur diesel and soybean biodiesel in different percentages, B5 and B20. PM sampling was performed using a Euro V - SCR engine operating in European Stationary Cycle (ESC). The PAHs and Nitro-PAHs were extracted from PM using an Accelerated Solvent Extractor and quantified by GC-MS. The results indicated that the use of SCR and the largest fraction of biodiesel studied may suppress the emission of total PAHs. The Toxic Equivalent (TEQ) was lower when using 20% biodiesel, in comparison with 5% biodiesel on the SCR system, reaffirming the low toxicity emission using higher percentage biodiesel. The data also reveal that use of SCR, on its own, suppress the Nitro-PAHs compounds. In general, the use of larger fractions of biodiesel (B20) coupled with the SCR aftertreatment showed the lowest PAHs and Nitro-PAHs emissions, meaning lower toxicity and, consequently, a potential lower risk to human health. From the emission point of view, the results of this work also demonstrated the viability of the Biodiesel programs, in combination with the SCR systems, which does not require any engine adaptation and is an economical alternative for the countries (Brazil, China, Russia, India) that have not adopted Euro VI emission standards.

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Underground emissions and miners’ personal exposure to diesel and renewable diesel exhaust in a Swedish iron ore mine

Gren

Krais

Assarsson

et al. 2022

Int Arch Occup Environ Health

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Purpose Underground diesel exhaust exposure is an occupational health risk. It is not known how recent intensified emission legislation and use of renewable fuels have reduced or altered occupational exposures. We characterized these effects on multipollutant personal exposure to diesel exhaust and underground ambient air concentrations in an underground iron ore mine. Methods Full-shift personal sampling (12 workers) of elemental carbon (EC), nitrogen dioxide (NO2), polycyclic aromatic hydrocarbons (PAHs), and equivalent black carbon (eBC) was performed. The study used and validated eBC as an online proxy for occupational exposure to EC. Ambient air sampling of these pollutants and particle number size distribution and concentration were performed in the vicinity of the workers. Urine samples (27 workers) were collected after 8 h exposure and analyzed for PAH metabolites and effect biomarkers (8-oxodG for DNA oxidative damage, 4-HNE-MA for lipid peroxidation, 3-HPMA for acrolein). Results The personal exposures (geometric mean; GM) of the participating miners were 7 µg EC m−3 and 153 µg NO2 m−3, which are below the EU occupational exposure limits. However, exposures up to 94 µg EC m−3 and 1200 µg NO2 m−3 were observed. There was a tendency that the operators of vehicles complying with sharpened emission legislation had lower exposure of EC. eBC and NO2 correlated with EC, R = 0.94 and R = 0.66, respectively. No correlation was found between EC and the sum of 16 priority PAHs (GM 1790 ng m−3). Ratios between personal exposures and ambient concentrations were similar and close to 1 for EC and NO2, but significantly higher for PAHs. Semi-volatile PAHs may not be effectively reduced by the aftertreatment systems, and ambient area sampling did not predict the personal airborne PAHs exposure well, neither did the slightly elevated concentration of urinary PAH metabolites correlate with airborne PAH exposure. Conclusion Miners’ exposures to EC and NO2 were lower than those in older studies indicating the effect of sharpened emission legislation and new technologies. Using modern vehicles with diesel particulate filter (DPF) may have contributed to the lower ambient underground PM concentration and exposures. The semi-volatile behavior of the PAHs might have led to inefficient removal in the engines aftertreatment systems and delayed removal by the workplace ventilation system due to partitioning to indoor surfaces. The results indicate that secondary emissions can be an important source of gaseous PAH exposure in the mine.

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Mitigation of PAH and Nitro-PAH Emissions from Nonroad Diesel Engines

Cited by 22 publications

References 32 publications

Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

Polycyclic Aromatic Hydrocarbons (PAHs) and nitrated analogs associated to particulate matter emission from a Euro V-SCR engine fuelled with diesel/biodiesel blends

Underground emissions and miners’ personal exposure to diesel and renewable diesel exhaust in a Swedish iron ore mine

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