| 1. |
- Alastuey, Andres, et al.
(författare)
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Geochemistry of PM10 over Europe during the EMEP intensive measurement periods in summer 2012 and winter 2013
- 2016
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 16:10, s. 6107-6129
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Tidskriftsartikel (refereegranskat)abstract
- The third intensive measurement period (IMP) organised by the European Monitoring and Evaluation Programme (EMEP) under the UNECE CLTRAP took place in summer 2012 and winter 2013, with PM10 filter samples concurrently collected at 20 (16 EMEP) regional background sites across Europe for subsequent analysis of their mineral dust content. All samples were analysed by the same or a comparable methodology. Higher PM10 mineral dust loadings were observed at most sites in summer (0.5-10aEuro-A mu gaEuro-m(-3)) compared to winter (0.2-2aEuro-A mu gaEuro-m(-3)), with the most elevated concentrations in the southern- and easternmost countries, accounting for 20-40aEuro-% of PM10. Saharan dust outbreaks were responsible for the high summer dust loadings at western and central European sites, whereas regional or local sources explained the elevated concentrations observed at eastern sites. The eastern Mediterranean sites experienced elevated levels due to African dust outbreaks during both summer and winter. The mineral dust composition varied more in winter than in summer, with a higher relative contribution of anthropogenic dust during the former period. A relatively high contribution of K from non-mineral and non-sea-salt sources, such as biomass burning, was evident in winter at some of the central and eastern European sites. The spatial distribution of some components and metals reveals the influence of specific anthropogenic sources on a regional scale: shipping emissions (V, Ni, and SO42-) in the Mediterranean region, metallurgy (Cr, Ni, and Mn) in central and eastern Europe, high temperature processes (As, Pb, and SO42-) in eastern countries, and traffic (Cu) at sites affected by emissions from nearby cities.
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| 2. |
- Hernández-Laguna, Alfonso, et al.
(författare)
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Compressibility of 2M1 muscovite-phlogopite series minerals
- 2019
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Ingår i: Journal of Molecular Modeling. - : Springer. - 1610-2940 .- 0948-5023. ; 25:11
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Tidskriftsartikel (refereegranskat)abstract
- Muscovite (Ms) and phlogopite (Phl) belong to the 2:1 dioctahedral and trioctahedral layer silicates, respectively, and are the end members of Ms-Phl series minerals. This series was studied in the 2M1 polytype and modeled by the substitution of three Mg2+ cations in the Phl octahedral sites by two Al3+ and one vacancy, increasing the substitution up to reach the Ms. The series was computationally examined at DFT level as a function of pressure to 9 GPa. Cell parameters as a function of pressure and composition, and bulk moduli as a function of the composition agrees with the existing experimental results. The mixing Gibbs free energy was calculated as a function of composition. From these data, approximated solvi were calculated at increasing pressure. A gap of solubility is found, decreasing the gap of solubility at high pressure.
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| 3. |
- Pérez-Rodríguez, Marta, et al.
(författare)
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Industrial-era lead and mercury contamination in southern Greenland implicates North American sources
- 2018
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 613, s. 919-930
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Tidskriftsartikel (refereegranskat)abstract
- To study the long-range transport of atmospheric pollutants from lower latitude industrial areas to the Arctic, we analysed a peat core spanning the last similar to 700 cal. yr (similar to 1300-2000 CE) from southern Greenland, an area sensitive to atmospheric pollution from North American and Eurasian sources. A previous investigation conducted in the same location recorded atmospheric lead (Pb) pollution after similar to 1845, with peak values recorded in the 1970s, and concluded that a North American source was most likely. To confirm the origin of the lead, we present new Pb isotope data from Sandhavn, together with a high-resolution record for mercury (Hg) deposition. Results demonstrate that the mercury accumulation rate has steadily increased since the beginning of the 19th century, with maximum values of 9.3 mu g m(-2) yr(-1) recorded similar to 1940. Lead isotopic ratios show two mixing lines: one which represents inputs from local and regional geogenic sources, and another that comprises regional geogenic and pollution sources. Detrending the Pb isotopic ratio record (thereby extracting the effect of the geogenic mixing) has enabled us to reconstruct a detailed chronology of metal pollution. The first sustained decrease in Pb isotope signals is recorded as beginning similar to 1740-1780 with the lowest values (indicating the highest pollution signature) dated to similar to 1960-1970. The 206Pb/207Pb ratio of excess Pb (measuring 1.222, and reflecting pollution generated Pb), when compared with the Pb isotopic composition of the Sandhavn peat record since the 19th century and the timing of Pb enrichments, clearly points to the dominance of pollution sources fromNorth America, although it did not prove possible to further differentiate the emissions sources geographically.
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