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The oxidative potential (OP) of the gas phase is an important and neglected aspect of environmental toxicity. Whilst prolonged exposure to particulate matter (PM) associated reactive oxygen species (ROS) have been shown to lead to negative health effects, the potential for compounds in gas phase to cause similar effects is yet to be understood. In this study we describe: the significance of the gas phase OP generated through vehicle emissions; discuss the origin and evolution of species contributing to measured OP; and report on the impact of gas phase OP on human lung cells. The model aerosol for this study was exhaust emitted from a Euro III Common-rail diesel engine fuelled with different blends of diesel and biodiesel. The gas phase of these emissions was found to be potentially as hazardous as the particle phase. Fuel oxygen content was found to negatively correlate with the gas phase OP, and positively correlate with particle phase OP. This signifies a complex interaction between reactive species present in gas and particle phase. Furthermore, this interaction has an overarching effect on the OP of both particle and gas phase, and therefore the toxicity of combustion emissions. [ABSTRACT FROM AUTHOR]

Oxidative potential (OP) is related to the organic phase, specifically to its oxygenated organic fraction (OOA). Furthermore, the oxygen content of fuel molecules has significant influence on particulate OP. Thus, this study aimed to explore the actual dependency of the OOA and ROS to the oxygen content of the fuel. In order to reach the goal, different biodiesels blends, with various ranges of oxygen content; have been employed. The compact time of flight aerosol mass spectrometer (c-ToF AMS) enabled better identification of OOA. ROS monitored by using two assays: DTT and BPEA-nit. Despite emitting lower mass, both assays agreed that oxygen content of a biodiesel is directly correlated with its OOA, and highly related to its OP. Hence, the more oxygen included in the considered biodiesels, the higher the OP of PM emissions. This highlights the importance of taking oxygen content into account while assessing emissions from new fuel types, which is relevant from a health effects standpoint. [ABSTRACT FROM AUTHOR]

Depending on CO 2 capture processes or hydrocarbon sources, fuel gas from boilers can be accompanied with impurities which could be co-injected in a geological storage. These gases, such as SOx, NOx, or oxygen could interact with reservoir fluids and rocks and well materials and could affect the safety of the storage. However, there are currently only few data on the behavior of such gas mixtures, as well as on their chemical reactivity, especially in the presence of water. The purpose of this paper is to develop experimental and analytical protocols in order to acquire new thermodynamic data on SO2 and NO under geological conditions of pressure and temperature using Raman spectrometry. [ABSTRACT FROM AUTHOR]

Highlights: [•] Absorption of carbon dioxide in ionic liquids containing carboxylate anions. [•] New processes for capture and separation of gases. [•] Chemisorption of the gas depends on the presence of water. [•] The mechanism of reaction depends on the nature of the ions of the ionic liquid. [ABSTRACT FROM AUTHOR]

Abstract: Influence of alternative fuels on diesel engine exhaust particle emission was investigated using an ultra-low sulfur diesel fuel as a baseline fuel where two biodiesels (canola & tallow), Fischer–Tropsch and bioethanol were used as alternative fuel. Both the biodiesels coming from canola and tallow feedstocks, as well as F-T were used as 100% to run the engine where up to 40% energy substitution by ethanol was achieved without any sacrifice of engine power output. It was found that up to 30% ethanol substitution reduced both particulate mass (PM) and particle number (PN) emission consistently for all load settings at 2000rpm, highest 59% reduction in PM and 70% reduction in PN observed at 100% load. As previously suggested the possible mechanism for the observed reduction is the oxidation of particulate matter by OH radicals which are in excess with ethanol fumigation. For 40% ethanol substitution some inconsistency was observed for PM emission at different loads but consistent reduction was found for PN. Condensation of unburned/partially burned hydrocarbons that later condense on existing soot might be responsible for this, as the maximum increase of PM was observed at quarter load where low in cylinder temperature favour to nucleation of unburned hydrocarbons. PM emission was also reduced in case of using 100% FT, and 100% biodiesel and the highest 90% reduction in PM was observed for biodiesel at 100% load with almost no difference between the two biodiesels itself. On the other side a considerable difference was observed between canola and tallow biodiesel in case of PN emission. Canola biodiesel increased PN, due to the presence of the nucleation mode, for almost an order of magnitude for all load and speed settings where no such increase was observed for tallow biodiesel. [Copyright &y& Elsevier]

Air pollution exposure is associated with a range of adverse health effects, including cardiovascular and respiratory diseases. Particle-bound ROS has been recognised as one of the prevailing parameters to indicate the toxic potential of airborne particulate matter (PM). The temporal variability of particle-bound ROS is a very important metric crucial for the improvement of public health and risk assessment policies. To our knowledge this is the first study aiming to investigate diurnal ROS profiles in both the particle and gas phase and associate them with diurnal variations of important pollutants. For that purpose, we have successfully applied a new instrument to continuously monitor diurnal ROS profiles at two locations in Hong Kong: a busy roadside and an urban background. Data was collected over both the working week and during weekends. We have observed a high correlation between particle-bound ROS and lower concentrations of black carbon (BC) at the roadside during the working week. These associations were less significant over the weekend and at all times with ozone. Our results suggest that most of the particle-bound ROS from both the particle and the gas phase arises from fresh emission sources directly from the traffic. A very interesting observation came out as a result of this study where measured ROS concentration was decreasing with the rise of ozone in conjunction with particle number, suggesting potential role of ROS in particle growth and aging. • First study investigating diurnal ROS profiles in particle and gas phase and association with diurnal pollutant profiles. • ROS from both the particle and the gas phase mostly arises from fresh emission sources directly from the traffic. • ROS decreased with the rise of ozone and particle number, suggesting potential role of ROS in particle growth and aging. • Quantitative and qualitative ROS gas phase analysis are crucial for assessing the health impacts of atmospheric pollution. • Nature of anthropogenic gaseous emissions is a very relevant metrics for health implications of various emissions. [ABSTRACT FROM AUTHOR]

Biodiesels produced from different feedstocks usually have wide variations in their fatty acid methyl ester (FAME) so that their physical properties and chemical composition are also different. The aim of this study is to investigate the effect of the physical properties and chemical composition of biodiesels on engine exhaust particle emissions. Alongside with neat diesel, four biodiesels with variations in carbon chain length and degree of unsaturation have been used at three blending ratios (B100, B50, B20) in a common rail engine. It is found that particle emission increased with the increase of carbon chain length. However, for similar carbon chain length, particle emissions from biodiesel having relatively high average unsaturation are found to be slightly less than that of low average unsaturation. Particle size is also found to be dependent on fuel type. The fuel or fuel mix responsible for higher particle mass (PM) and particle number (PN) emissions is also found responsible for larger particle median size. Particle emissions reduced consistently with fuel oxygen content regardless of the proportion of biodiesel in the blends, whereas it increased with fuel viscosity and surface tension only for higher diesel-biodiesel blend percentages (B100, B50). However, since fuel oxygen content increases with the decreasing carbon chain length, it is not clear which of these factors drives the lower particle emission. Overall, it is evident from the results presented here that chemical composition of biodiesel is more important than its physical properties in controlling exhaust particle emissions. [ABSTRACT FROM AUTHOR]

Using Zn2+ions as new method, several FUs have been isolated from molluscan Hc Rapana venosa wihtout formation of non-functional proteolytic side products. N-terminal sequences of these fragments in comparison with FUS from other gastropodan Hcs show a very high degree of structural identity. Four Fus, purified from enzyme-treated structural subunits RvH1 and RvH2 (RvH1-a, RvH1-f, RvH2-a and RvH2-e) show identical N-terminal sequences compared to fragments isolated after treatment with Zn2+ ions. However, in some cases trypsin cleaves RvH chains at different positions if compared to the Zn2+ treatment.To analyze the oligosaccharide composition of two FUS from the first structural subunit of Rapana Hc, RvH1-a and RvH1-f, several techniques were applied: capillary electrophoresis, MALDI-MS, ESI-MS in combination with glycosidase digestions. On basis of these results and the determined amino acid sequence two N-linkage sites were identified in the FU RvH1-a, but only one in the FU RvH1-f. [Copyright &y& Elsevier]