Abstract: The new European Council Directive (PE-CONS 3696/07) frames the inhalable (PM10) and fine particles (PM2.5) on priority to chemically characterize these fractions in order to understand their possible relation with health effects. Considering this, PM2.5 was collected during four different seasons to evaluate the relative abundance of bulk elements (Cl, S, Si, Al, Br, Cu, Fe, Ti, Ca, K, Pb, Zn, Ni, Mn, Cr and V) and water soluble ions (F−, Cl−, NO2 −, NO3 −, SO4 2−, Na+, NH4 +, Ca2+ and Mg2+) over Menen, a Belgian city near the French border. The air quality over Menen is influenced by industrialized regions on both sides of the border. The most abundant ionic species were NO3 −, SO4 2− and NH4 +, and they showed distinct seasonal variation. The elevated levels of NO3 − during spring and summer were found to be related to the larger availability of the NOx precursor. The various elemental species analyzed were distinguished into crustal and anthropogenic source categories. The dominating elements were S and Cl in the PM2.5 particles. The anthropogenic fraction (e.g. Zn, Pb, and Cu) shows a more scattered abundance. Furthermore, the ions and elemental data were also processed using principal component analysis and cluster analysis to identify their sources and chemistry. These approach identifies anthropogenic (traffic and industrial) emissions as a major source for fine particles. The variations in the natural/anthropogenic fractions of PM2.5 were also found to be a function of meteorological conditions as well as of long-range transport of air masses from the industrialized regions of the continent.

Abstract: The main goal of this work was to determine the chemical composition of building materials used in Turkey by utilizing energy dispersive X-ray fluorescence (EDXRF) spectrometry. Gas concrete, cement, sand, bricks, roofing tiles, marble, lime and gypsum materials were selected as building materials for this research. The chemical contents and their trace concentrations of the selected samples were determined. The most abundant oxides measured were generally SiO2, Al2O3, CaO, MgO, Fe2O3, K2O and SO3 for all samples. While the main chemical component of gas concrete, cement, sand and marble samples were SiO2 and CaO, brick and roofing tile mainly consisted of SiO2 and Al2O3. CaO and SO3 were major component of lime and gypsum samples, respectively. For U and Th concentrations in the samples, activities of 226Ra and 232Th were measured by utilizing gamma spectrometry. ANOVA and Pearson correlation analyses were performed on the studied data for statistical analysis.

Abstract: The results of Chemkar PM10, the first large scale chemical characterisation project of PM10 in Flanders are presented. Between September 2006 and September 2007 a total of 365 PM10 samples were collected by sampling every sixth day at six different sites in Flanders (Belgium) varying in character from urban background to rural. Samples were analysed for a series of elements, elemental and organic carbon, 13C/12C- and 15N/14N-isotopic ratios, and water-soluble ions. At three sites extra sampling was carried out to determine PAHs by means of a novel technique that uses sorption tubes consisting of polydimethylsiloxane (PDMS) foam, PDMS particles and a TENAX TA bed. Results showed that the most important fractions were secondary inorganic ions (nitrate, sulphate and ammonium): 41% (12.6 μg m−3), organic matter: 20% (6.1 μg m−3), crustal matter: 14% (4.3 μg m−3), sea salt: 8% (2.4 μg m−3) and elemental carbon: 4% (1.2 μg m−3). Although the general composition profile was rather similar for the six sites, substantial differences could be observed for some main components and for several trace metals such as chromium, copper, zinc, arsenic and lead. Although the average sum of the PAH 16 was quite variable between the three sites (between 132 and 248 ng m−3) the average sum of the PAH 7 was between 7 and 9 ng m−3 for the three sites. The largest relative differences between sites were found for elemental carbon and crustal matter, thereby indicating that there is some potential for local measures to reduce the concentrations of particulate matter by a few μg m−3. Both for carbon and nitrogen isotopic ratios significant differences in time were observed. Isotopic differences in location could only be detected for carbon.

Abstract: Wall paintings make up an important section of cultural heritage. They resemble time portals that can be used to travel back into the past and witness the life of our ancestors. In these paintings, the ancient artists depicted the different aspects of their life, such as cooking, baking, farming, manufacturing, as well as thoughts and beliefs. Unfortunately, wall paintings are susceptible to degradation over time in the form of the accumulations of dirt and deposits on the painted surfaces and loss of adhesion of the paint layers at the surface. Therefore, the removal of these deposits is one of the primary duties of conservator-restorers. Such operations are intended to restore the painted surface to a condition close enough to its original state. Since cleaning artworks may cause undesirable physicochemical alterations and is nonreversible, the proper cleaning procedure should be adopted. In this regard, numerous gels have been developed and exploited for the cleaning of various artwork surfaces. Lately, polyvinyl alcohol-borax (PVA-B) and agarose (AG) hydrogels have been widely employed as cleaning materials by conservator-restorers. However, both hydrogels have shown limitations in specific cleaning practices. In this work, we investigated a new double network hydrogel based on blending PVA-B and agarose to avoid the limitations posed by the constituting hydrogels. For this reason, a detailed characterization of the PVA–B/AG double network hydrogel was performed, including chemical structure, liquid phase retention, mechanical strength, rheological behavior, and self-healing behavior of various PVA-B/AG hydrogels. These new hydrogels revealed better properties than PVA-B and agarose hydrogels and obviated their limitations. A laboratory experiment on the removal of deteriorated Paraloid® B72 proved that the PVA-B/AG hydrogel loaded 10%/10% MEK/1-PeOH was able to remove these layers efficiently. Therefore, the hydrogel was tested on a wall painting from the Temple of Seti I in Abydos – Egypt. It removed the glossy/darkened consolidant from the wall painting and restored the original matt appearance of the painted surface. In another application on the painted ceiling of the same temple, the hydrogel was tested for removing thick soot layers. The hydrogel formulation (loaded with 5% ammonia, 0.3% ammonium carbonate, and 0.3% EDTA) removed these layers with no noticeable damage to the paint layers. In a wide-scale application of the hydrogel (loaded with 10% propylene carbonate), it removed a highly deteriorated varnish layer from a 19-c wall painting. All the traditional cleaning methods employed caused damage to the paint layers, proving that gel cleaning can be a safer cleaning alternative in some cases.

Abstract: Infrared thermography is a fast, non-destructive and contactless testing technique which is increasingly used in heritage science. The aim of this study was to assess the ability of infrared thermography, in combination with a data clustering approach, to differentiate between the different types of historical glass that were included in a colorless leaded-glass windows during previous restoration interventions. Inspection of the thermograms and the application of two data mining techniques on the thermal data, i.e., k-means clustering and hierarchical clustering, allowed identifying different groups of window panes that show a different thermal behavior. Both clustering approaches arrive at similar groupings of the glass with a clear separation of three types. However, the lead cames that hold the glass panes appear to have a substantial impact on the thermal behavior of the surrounding glass, thus preventing classification of the smallest glass panes. For the larger panes, this was not a critical issue as the center of the glass remained unaffected. Subtle visual color differences between panes, implying a variation in coloring metal ions, was not always distinguished by IRT. Nevertheless, data clustering assisted infrared thermography shows potential as an efficient and swift method for documenting the material intervention history of leaded-glass windows during or in preparation of conservation treatments.