PAHs in the Fraser River basin: a critical appraisal of PAH ratios as indicators of PAH source and composition

PAH source fingerprints for coke ovens, diesel and, gasoline engines, highway tunnels, and wood combustion emissions

Tropospheric air pollution has impacts on scales ranging from local to global. Reactive intermediates in the oxidation of mixtures of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) play central roles: the hydroxyl radical (OH), during the day; the nitrate radical (NO3), at night; and ozone (O3), which contributes during the day and night. Halogen atoms can also play a role during the day. Here the implications of the complex VOC-NOx chemistry for O3 control are discussed. In addition, OH, NO3, and O3 are shown to play a central role in the formation and fate of airborne toxic chemicals, mutagenic polycyclic aromatic hydrocarbons, and fine particles.

https://science.sciencemag.org/content/sci/276/5315/1045.full.pdf

Tropospheric air pollution: ozone, airborne toxics, polycyclic aromatic hydrocarbons, and particles.

Gas- and particle-phase tailpipe emissions from late-model medium duty diesel trucks are quantified using a two-stage dilution source sampling system. The diesel trucks are driven through the hot-start Federal Test Procedure (FTP) urban driving cycle on a transient chassis dynamometer. Emission rates of 52 gas-phase volatile hydrocarbons, 67 semivolatile and 28 particle-phase organic compounds, and 26 carbonyls are quantified along with fine particle mass and chemical composition. When all C_1−C_(13) carbonyls are combined, they account for 60% of the gas-phase organic compound mass emissions. Fine particulate matter emission rates and chemical composition are quantified simultaneously by two methods:  a denuder/filter/PUF sampler and a traditional filter sampler. Both sampling techniques yield the same elemental carbon emission rate of 56 mg km^(-1) driven, but the particulate organic carbon emission rate determined by the denuder-based sampling technique is found to be 35% lower than the organic carbon mass collected by the traditional filter-based sampling technique due to a positive vapor-phase sorption artifact that affects the traditional filter sampling technique. The distribution of organic compounds in the diesel fuel used in this study is compared to the distribution of these compounds in the vehicle exhaust. Significant enrichment in the ratio of unsubstituted polycyclic aromatic hydrocarbons (PAH) to their methyl- and dimethyl-substituted homologues is observed in the tailpipe emissions relative to the fuel. Isoprenoids and tricyclic terpanes are quantified in the semivolatile organics emitted from diesel vehicles. When used in conjunction with data on the hopanes, steranes, and elemental carbon emitted, the isoprenoids and the tricyclic terpanes may help trace the presence of diesel exhaust in atmospheric samples.

Measurement of emissions from air pollution sources. 2. c1 through c30 organic compounds from medium duty diesel trucks

Chemical characterization of particulate emissions from diesel engines: A review

Exhaust emission from a heavy-duty diesel vehicle during transient driving conditions have been characterized chemically and tested for mutagenicity. Both the particulate phase and the semivolatile phase were investigated chemically and by the Ames test. Three different sampling techniques, i.e., cryocondensation and two adsorbents XAD-2 and polyurethane foam (PUF), were used for collection of the semivolatile phase together with a particulate filter situated upstream. The cryogenic technique was the least efficient type and the PUF technique gave the highest recovery of polycyclic aromatic hydrocarbons (PAH) and mutagenic activity. The amount of PAH, mainly three-ringed PAH, emitted in the semivolatile phase was approximately 3 time higher than that emitted in the particulate phase. The contribution of the semivolatile phase to the total mutagenicity was approximately 20% in strain TA100 {plus minus} S9, 10% in strain TA98-S9, and 37% in strain TA98 + S9. The results thus show the importance of both particulate- and semivolatile-phase-associated compounds when possible health effects from diesel engine exhausts are being considered.

Chemical and biological characterization of particulate-, semivolatile-, and gas-phase-associated compounds in diluted heavy-duty diesel exhausts: a comparison of three different semivolatile-phase samplers

Diesel fuels, classified as environmentally friendly, have been available on the Swedish market since 1991. The Swedish diesel fuel classification is based upon the specification of selected fuel composition and physical properties to reduce potential environmental and health effects from direct human exposure to exhaust. The objective of the present investigation was to compare the most stringent, environmentally classified Swedish diesel fuel (MK1) to the reference diesel fuel used in the "European Program on Emissions, Fuels and Engine Technologies" (EPEFE) program. The study compares measurements of regulated emissions, unregulated emissions, and biological tests from a Volvo truck using these fuels. The regulated emissions from these two fuels (MK1 vs EPEFE) were CO (-2.2%), HC (12%), NOx (-11%), and particulates (-11%). The emissions of aldehydes, alkenes, and carbon dioxide were basically equivalent. The emissions of particle-associated polycyclic aromatic hydrocarbons (PAHs) and 1-nitropyrene were 88% and 98% lower than those of the EPEFE fuel, respectively. The emissions of semi-volatile PAHs and 1-nitropyrene were 77% and 80% lower than those from the EPEFE fuel, respectively. The reduction in mutagenicity of the particle extract varied from -75 to -90%, depending on the tester strain. The reduction of mutagenicity of the semi-volatile extract varied between -40 and -60%. Furthermore, the dioxin receptor binding activity was a factor of 8 times lower in the particle extracts and a factor of 4 times lower in the semi-volatile extract than that of the EPEFE fuel. In conclusion, the MK1 fuel was found to be more environmentally friendly than the EPEFE fuel.

Comparison of exhaust emissions from Swedish environmental classified diesel fuel (MK1) and European Program on Emissions, Fuels and Engine Technologies (EPEFE) reference fuel : a chemical and biological characterization, with viewpoints on cancer risk

Jacob Almén

Papers

Chemical and biological characterization of particulate-, semivolatile-, and gas-phase-associated compounds in diluted heavy-duty diesel exhausts: a comparison of three different semivolatile-phase samplers

Comparison of exhaust emissions from Swedish environmental classified diesel fuel (MK1) and European Program on Emissions, Fuels and Engine Technologies (EPEFE) reference fuel : a chemical and biological characterization, with viewpoints on cancer risk

Cold start emissions at +22, −7 and −20°C ambient temperatures from a three-way catalyst (TWC) car: regulated and unregulated exhaust components

Exhaust emissions from gasoline-fuelled light duty vehicles operated in different driving conditions: A chemical and biological characterization

Estimation of aliphatic amine emissions in automobile exhausts