Found 10066 publications. Showing page 161 of 403:
Chemical speciation of fine airborne particles in Abu Dhabi. NILU OR
Chemical speciation results of PM2.5 filter samples from eight sites in Abu Dhabi are discussed. This is the third interim report, covering a total of 40 filter samples. As one aim of this sampling study was to use the speciation results for health impact studies, samples with high particle loads and high degree of blackness were selected for analysis, and compared to samples with typical particle loads. Particles with diameters less than 2.5 µm were analysed for elements, inorganic ions and carbonaceous fractions.
The most abundant elements were found to be crustal elements, contributing on average 14% to PM2.5 mass. Reconstructing the mass of crustal oxides, approximately 44% of the fine particle mass was estimated to be associated with mineral dust. The concentrations of most heavy metals were below limit values for annual averages at all sites. For nickel, it was found that the Guideline Value may be exceeded at one traffic site.
Inorganic ions (sulphate, nitrate, ammonium, sodium, chloride) explain on average 34% of the PM2.5 mass in Abu Dhabi. Remarkably high sulphate concentrations account for the major part (on average 26%). Particulate sulphate in Abu Dhabi is likely to have both natural (as a result of the local composition of mineral dust) and anthropogenic sources which cannot be separated with the applied analytical methods. An anthropogenic contribution of ~6% comes from the secondary inorganic ions nitrate and ammonium.
Total carbon, which consists of elemental carbon, organic carbon and carbonate carbon contributed on average 14% to PM2.5 mass. About 30% of total carbon was estimated to be carbonate of likely natural origin. Elemental carbon and most organic carbon are expected to be of anthropogenic origin.
PM in Abu Dhabi has a strong signature of natural sources (mineral dust). A detailed apportionment of sources requires further analyses.
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Tunnels along E134, Kongsberg. Evaluating air quality around openings of tunnels. NILU OR
Dispersion calculations regarding the tunnel connections along E134, Kongsberg. Maximum concentrations and dispersion distances have been calculated.
2011
Dispersion calculations of F to ambient air from an ironsilica refining plant at Mo I Rana. NILU OR
Dispersion calculations have been carried out for emissions of F to ambient air from an ironsilica refining plant at Mo I Rana
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2011
Modeling of short chain chlorinated paraffins in the Nordic environment. NILU PP
Short chain chlorinated paraffins (SCCPs), also called polychlorinated n-alkanes, are mixtures of compounds of molecular formula CxH2x+2-yCly containing 10-13 carbon atoms and usually 30-70 % degree of chlorination. They have a range of industrial applications, and have been detected in numerous environmental compartments. There is concern regarding SCCPs due to their environmental persistence and their potential for bioaccumulation, adverse effects and long-range transport. SCCPs have been included in the UNECE LRTAP Convention, the priority substance list of the European Water Framework Directive, and are under consideration for the Stockholm Convention on Persistent Organic Pollutants. However, the behaviour and fate of SCCPs remain poorly understood, in part as the technical mixtures consist of thousands of isomers, enantiomers and diastereomers, which make analysis and modelling of these compounds very challenging. The purpose of this study was to explore a complementary modelling and monitoring approach to evaluate the overall understanding of the link between emissions of SCCPs, environmental levels and human exposure in the Nordic environment and to identify the more critical knowledge gaps. Data for emissions and physicochemical properties of SCCPs were gathered or estimated, and used to parameterize an integrated, non-steady state environmental fate and bioaccumulation model (CoZMoMan). Specific congeners of SCCPs were selected for the study to assess the extent of expected variation of environmental fate and behaviour within the multitude of compounds. Model results were next compared to reported environmental levels in the Nordic region. For compartments where environmental levels were scarce or lacking, targeted sampling and analysis was carried out to further evaluate the model predictions. Results from this study will be presented and discussed with emphasis on the more critical research needs with respect to the overall fate and exposure of SCCPs.
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Recent studies show that PCB (polychlorinated biphenyl) air concentrations remain surprisingly high in parts of Africa and Asia. These are regions where PCBs were never extensively used, but which are implicated as recipients of obsolete products and wastes containing PCBs and other industrial organic contaminants. We hypothesize that there may be different trends in emissions across the globe, whereby emissions of some industrial organic contaminants may be decreasing faster in former use regions (due to emission reductions combined with uncontrolled export), at the expense of regions receiving these substances as obsolete products and wastes. While significant efforts and achievements have been made by the scientific community to understand and predict LRT of such chemicals by air and water, it is cautioned that the global sources and fate of these chemicals still cannot be fully rationalized (nor controlled) without an understanding of emissions due to ¿LRT¿ by products and wastes. However, the potential for detrimental effects on the environment and human health due to LRT by air, water, or wastes should be of equal concern when managing and regulating industrial organic contaminants. This calls for a better integration of life-cycle approaches in the management and regulation of industrial organic contaminants in order to protect environmental and human health on a global scale. Yet, in comparison to LRT by air and water, little remains known about the LRT of industrial organic contaminants as obsolete products and wastes because of the often illicit nature of these operations.
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Monitoring long-range transboundary air pollution 2010. Summary report. NIVA-rapport, 6183-2011
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