Search

Highlights • Construction materials from Me-taw-ya Temple (Pagán Valley, Burma) were studied. • Statistical treatment on compositional data discriminated the materials. • Integrated scientific investigations identified different compositional groups. • The provenance of construction raw materials was hypothesised for the first time. Abstract Diagnostic research was carried out to acquire information on Me-taw-ya temple, Pagán archaeological area, Burma (Myanmar). Throughout the centuries the temple was severely damaged by a series of strong earthquakes, the most recent one taking place in 2016. Our principle aim was to acquire information on the building's constituting materials (i.e. bricks, mortars and stuccoes) to determine how the temple was constructed, an essential tool for the development of conservation/restoration projects in compliance with international guidelines and standards. The archaeometric study used selected samples to undertake an integrated application of preliminary in situ non-invasive ED-XRF investigations and micro invasive analyses. Optical microscopy observations, FT-IR, XRD and TG analyses were performed to identify the mineralogical and chemical composition of materials. Samples were categorized using principal component analysis (PCA). Hierarchical cluster analysis (HCA) were also performed on EDXRF chemical compositional data. Results have delineated a series of considerations linking the geographical origin of the constituting materials to local sources as well as clarifying their formulation and use in the construction of Me-taw-ya temple. Results were used to identify compatible materials for conservation treatments. [ABSTRACT FROM AUTHOR]

This paper deals with the analysis of black crust coming from the statue of Oceanus belonging to the Fontana di Trevi (Rome). This monument is undoubtedly one of the main touristic attractions of Rome. During the restoration held between 2014 and 2015, some diagnostic analyses had been carried out. It has been highlighted that the sheltered surfaces suffer the formation of black crust, especially on the marble statues. The possibility to sample those degradation products, together with the unaltered substrate, represented an excellent opportunity to characterize the marble itself, to assess the impact of the urban air pollution on the stone material, and to detect the pollutant on a precise timescale. In fact, it is known that the previous restoration of the fountain had been carried out between 1989 and 1991 then, information about the air pollution over the last 25 years can be highlighted, because it has been proved that black crusts act as passive samplers of pollution. In order to fully characterize those samples, several techniques were used, including optical and scanning electron microscopy, X-ray diffraction, laser ablation inductively coupled plasma mass spectrometry, infrared spectroscopy and ion chromatography. Furthermore, a new methodology based on CHN (Carbon, Hydrogen, Nitrogen) analysis has been developed for the quantification of the two main constituents of the carbonaceous fraction present in the black crusts, i.e. OC (organic carbon) and EC (elemental carbon). This integrated approach proposed in the present study allowed us to gain information about the mineralogical phases and the elements within the crusts and at the crust-substrate interface, giving the possibility to identify the pollution sources causing the stone decay within the monument. [ABSTRACT FROM AUTHOR]

During a sampling campaign, carried out during June 2012, inside some traditional households located in four villages (Phakding, Namche, Pangboche and Tukla) of Mt. Everest region in southern part of the central Himalaya (Nepal), particulate matter (PM) depositions and ashes have been collected. Moreover, outdoor PM depositions have also been analyzed. Chemical characterization of PM depositions and ashes for major ions, organic carbon, elemental carbon (EC), metal content and PAHs (Polycyclic Aromatic Hydrocarbons) allowed identifying, as major contributes to indoor PM, the following sources: biomass burning, cooking and chimney ashes. These sources significantly affect outdoor PM depositions: in-house biomass burning is the major source for outdoor EC and K + as well as biomass burning and cooking activities are the major sources for Polycyclic Aromatic Hydrocarbons. [ABSTRACT FROM AUTHOR]

Human exposure to polycyclic aromatic hydrocarbons (PAHs) in indoor environments can be particularly relevant because people spend most of their time inside buildings, especially in homes. This study aimed to investigate the most important particle-bound PAH sources and exposure determinants in PM 2.5 samples collected in 19 homes located in northern Italy. Complementary information about ion content in PM 10 was also collected in 12 of these homes. Three methods were used for the identification of PAH sources and determinants: diagnostic ratios with principal component and hierarchical cluster analyses (PCA and HCA), chemical mass balance (CMB) and linear mixed models (LMMs). This combined and tiered approach allowed the infiltration of outdoor PAHs into indoor environments to be identified as the most important source in winter, with a relevant role played by biomass burning and traffic exhausts to be identified as a general source of PAHs in both seasons. Tobacco smoke exhibited an important impact on PAH levels in smokers' homes, whereas in the whole sample, cooking food and natural gas sources played a minor or negligible role. Nitrate, sulfate and ammonium were the main inorganic constituents of indoor PM 10 owing to the secondary formation of ammonium sulfates and nitrates. [ABSTRACT FROM AUTHOR]

Abstract: Aim of this study was to determine by Ion Chromatography ions (Na+, Ca++, Mg++, NH4 +, Cl−, Br−, SO4 2−, NO3 −, PO4 3−) in honeys (honeydew and floral nectar honeys) from different Italian Regions and from countries of the Western Balkan area. The compositional data were processed by multivariate analysis (PCA and HCA). Arboreal honeydew honeys from the Western Balkans had higher concentrations (from two to three times) of some environmental pollutants (Br−, SO4 2− and PO4 3− contents), due to industrial and agricultural activities, than those from Italian regions. The cationic profiles were very similar in both groups. Multivariate analysis indicated a clear difference between nectar honeys and arboreal/honeydew honeys (recognition of the botanical origin). These findings point to the potential of ionic constituents of honey as indicators of environmental pollution, botanical origin and authenticity. [Copyright &y& Elsevier]

The purpose of this study is to investigate the use of a new quantitative analysis method in case total reflection X-ray fluorescence (TXRF) is applied to archaeological ceramics. This method is alternative to and simpler than traditional TXRF quantitative analysis or typical techniques of elemental analysis such as atomic emission and absorption spectrometry (AES and AAS) which implies the chemical digestion of the sample. A new procedure which allows to obtain an homogeneous sample has been successfully applied. This way it was possible to obtain quantitative results for the elements present in the sedimentation obtained from a suspension prepared with the ceramic sample, by resorting to addition of an internal standard. The archaeological ceramic shards have been also chemically digested and analyzed by inductively coupled plasma-atomic emission spectrometry, AES with flame atomization and electrothermal atomic absorption spectrometry. The quantitative data obtained by means of both TXRF, AAS and AES were compared and worked out by multivariate statistical techniques, such as principal components analysis and hierarchical cluster analysis in order to achieve information concerning pottery provenance. [Copyright &y& Elsevier]

In the present paper total suspended particulate matter (TSP) was collected at the S. Marco Museum in Florence during seasonal monitoring campaigns carried out in 2013 and 2014. The analyses focused on the determination of TSP chemical composition: main ions, organic carbon (OC), elemental carbon (EC), water soluble organic compounds (WSOC) and levoglucosa which is considered the specific marker for wood burning. The analysis of TSP composition in Florence historical centre is of interest to assess what the damage caused to the surfaces of the urban monumental heritage could be. TSP higher value has been registered during December 2013 (58,6 μg/m3 ± 7,3 μg/m3) while the lower value has been registered in July 2013 (28,5 μg/m3 ± 2,2 μg/m3). OC and EC were also higher in winter with respect to summer. Sulphate is characterized by quite constant values during all the examined periods while ammonium and nitrate were higher in winter. The seasonal contribution of different sources such as combustion processes (from traffic and wood burning) and soil dust resuspension has been evidenced. In particular during winter a high concentration of levoglucosan, the specific marker for wood combustion, has been determined. Finally, all the data obtained were correlated with those previously determined in another study carried out in 2003 at the Baptistery of San Giovanni in Florence in order to evaluate any possible change in the atmospheric pollution composition. Unlabelled Image • Chemical characterization of TSP to study the impact on urban heritage in Florence • Ions, OC, EC, WSOC and levoglucosan analysis • Impact of traffic and wood burning during wintertime • Comparison with data acquired 10 years ago to indicate atmospheric pollution change [ABSTRACT FROM AUTHOR]

This paper deals with the archaeometric characterization of the bricks belonging to Tol-a Ajori Gate, one of the most important excavated sites on the Iranian plateau (Fars, Iran), close to the World Cultural Heritage of Persepolis. The archaeological excavations were carried out between 2011 and 2016 and brought to light a monumental building. The wall of the structure is built with mud and fired bricks sometimes glazed that are very similar to the elements of Babylon's Ishtar Gate. Several investigations were carried out on the bricks in order to investigate the technology process and to compare their composition with local clays, as potential raw materials collected nearby the archaeological site. The brick samples were investigated using different analytical techniques (Optical Microscopy, XRD, XRF, SEM-EDX, FT-IR/ATR, TGA, STA and Micro-Raman) to point out differences in chemical and mineralogical composition. Raw clay samples were submitted to XRD, XRF, SEM-EDX and FT-IR/ATR analyses. A wide homogeneity is present for all the considered bricks: Ca-rich clays with quartz-rich temper were used, this possibly suggesting a common raw material origin. Firing temperatures interval was estimated around 850–900 °C. A multivariate data treatment (PCA and HCA analysis) was applied to the XRF data set acquired for both clays and bricks. PCA suggests that Polvar alluvial clays could be the source raw material for mostly of Tol-e Ajori's bricks and more than one clay deposit was probably used. [ABSTRACT FROM AUTHOR]

• Polyamidoamine (PAA) coatings protect cotton fabrics from photo-oxidation. • Upon UV-irradiation, α-amino acid derived-polyamidoamines act as radical scavengers. • PAA ability to interfere with radical propagation is due to the tert-amine groups. • Only the glutamic-acid based PAA showed structural changes after photoaging. Four water-soluble α-amino acid-derived polyamidoamines (PAAs) obtained by reacting N,N'-methylenebisacrylamide with glycine, leucine, arginine and glutamic acid were studied as photostabilizers of cotton. Untreated and PAA-treated cotton strips with 10 % PAA add-on underwent accelerated photoaging by UV irradiation in air at temperature from 25 to 50°C and 30 % relative humidity. Irradiation was applied in consecutive 4 h cycles, after each of which samples were analyzed by different techniques. After 30 h irradiation, the whiteness index and colorimetric parameters indicated significant yellowing of cotton, which became slightly more intense after 100 h irradiation. On irradiation, PAA-treated samples showed only slow decrease in whiteness and increase in yellowing. After 100 h, yellowing achieved significantly lower levels than in untreated cotton. In no case did the infrared spectroscopy and electron microscopy reveal detectable structural and morphological alterations, even after 100 h of UV exposure. Thermogravimetric analysis showed only little changes of thermograms following photoaging. X-ray diffraction analysis revealed slight deformation of the cellulose crystalline structure following both PAA treatment and UV irradiation. Finally, the PAA coatings were extracted from the cotton strips and analyzed by 1H-NMR analysis. Only the glutamic acid-derived PAA showed detectable structural changes that did not involve the main chain. The FT-IR spectra and white indexes of the washed cotton strips did not differ from those of untreated cotton. Overall, it was proven that α-amino acid-derived PAAs protect cotton from photo-oxidation. Their performance was attributed to the radical scavenging ability of tert-amine groups present in their repeat units. [ABSTRACT FROM AUTHOR]

A sol–gel reaction starting from Si and Zr alkoxides, in water-ethanol mixtures, was employed to obtain iron doped zirconium silicate powders (zircon). The starting amount of the ferric salt in the sol–gel reacting mixture was varied in order to obtain Fe2O3/Zr molar ratios in the range 0.7–10%. The products of the sol–gel reaction were calcined in the range 800–1300 °C. X-ray diffractograms, EDX analyses and diffuse reflectance spectra were obtained and analysed for all the calcined powders; the colour of the pigments was characterised on the grounds of the CIE (Commission Internationale de l’Eclairage) standard procedure (CIE L*a*b* measurements). Results from the structural and spectral characterisations are examined and cross-compared to produce a consistent picture of the role played by iron on the promotion of the zircon lattice and on the optical properties of the reaction products. [Copyright &y& Elsevier]

An interlaboratory comparison was performed to evaluate the analytical methods for quantification of anhydrosugars – levoglucosan, mannosan, galactosan – and biosugars – arabitol, glucose and mannitol – in atmospheric aerosol. The performance of 10 laboratories in Italy currently involved in such analyses was investigated on twenty-six PM (particulate matter) ambient filters, three synthetic PM filters and three aqueous standard solutions. An acceptable interlaboratory variability was found, determined as the mean relative standard deviation (RSD%) of the results from the participating laboratories, with the mean RSD% values ranging from 25% to 46% and decreasing with increasing sugar concentration. The investigated methods show good accuracy, evaluated as the percentage error (ε%) related to mean values, since method biases ranged within ±20% for most of the analytes measured in the different laboratories. The detailed investigation (ANOVA analysis at p < 0.05) of the contribution of each laboratory to the total variability and the measurement accuracy shows that comparable results are generated by the different methods, despite the great diversity in terms of extraction conditions, chromatographic separation - more recent LC (liquid chromatography) and EC (exchange chromatography) methods compared to more widespread GC (gas chromatography) - and detection systems, namely PAD (pulsed amperometric detection) or mass spectrometry. [ABSTRACT FROM AUTHOR]

This work is part of the TOBICUP (TOxicity of BIomass Combustion generated Ultrafine Particles) project which aimed at providing the composition of ultrafine particles (UFPs, i.e. particles with aerodynamic diameter, d ae , lower than 100 nm) emitted by wood combustion and elucidating the related toxicity. Results here reported are from two ambient monitoring campaigns carried out at an alpine town in Northern Italy, where wood burning is largely diffused for domestic heating in winter. Wintertime and summertime UFP samples were analyzed to assess their chemical composition (i.e. elements, ions, total carbon, anhydrosugars, and polycyclic aromatic hydrocarbons) and biological activity. The induction of the pro-inflammatory cytokine interleukin-8 (IL-8) by UFPs was investigated in two human cells lines (A549 and THP-1) and in human peripheral blood leukocytes. In addition, UFP-induced oxidative stress and genotoxicity were investigated in A549 cells. Ambient UFP-related effects were compared to those induced by traffic-emitted particles (DEP) taken from the NIES reference material “vehicle exhaust particulates”. Ambient air UFPs induced a dose-related IL-8 release in both A549 and THP-1 cells; the effect was more relevant on summer samples and in general THP-1 cells were more sensitive than A549 cells. On a weight basis our data did not support a higher biological activity of ambient UFPs compared to DEP. The production of IL-8 in the whole blood assay indicated that UFPs reached systemic circulation and activated blood leukocytes. Comet assay and γ-H2AX evaluation showed a significant DNA damage especially in winter UFPs samples compared to control samples. Our study showed that ambient UFPs can evoke a pulmonary inflammatory response by inducing a dose-related IL-8 production and DNA damage, with different responses to UFP samples collected in the summer and winter periods. [ABSTRACT FROM AUTHOR]

Two common types of wood (beech and fir) were burned in commercial pellet (11.1 kW) and wood (8.2 kW) stoves following a combustion cycle simulating the behavior of a real-world user. Ultrafine particulate matter (UFP, d p < 100 nm) was sampled with three parallel multistage impactors and analyzed for metals, main water soluble ions, anhydrosugars, total carbon, and PAH content. The measurement of the number concentration and size distribution was also performed by a fourth multistage impactor. UFP mass emission factors averaged to 424 mg/kg fuel for all the tested stove and wood type (fir, beech) combinations except for beech log burning in the wood stove (838 mg/kg fuel ). Compositional differences were observed for pellets and wood UFP samples, where high TC levels characterize the wood log combustion and potassium salts are dominant in every pellet sample. Crucial aspects determining the UFP composition in the wood stove experiments are critical situations in terms of available oxygen (a lack or an excess of combustion air) and high temperatures. Whereas for the automatically controlled pellets stove local situations (e.g., hindered air-fuel mixing due to heaps of pellets on the burner pot) determine the emission levels and composition. Wood samples contain more potentially carcinogenic PAHs with respect to pellets samples. Some diagnostic ratios related to PAH isomers and anhydrosugars compiled from experimental UFP data in the present study and compared to literature values proposed for the emission source discrimination for atmospheric aerosol, extend the evaluation usually limited to higher particle size fractions also to UFP. [ABSTRACT FROM AUTHOR]

This study aimed to collect, characterize ultrafine particles (UFP) generated from the combustion of wood pellets and logs (softwood and hardwood) and to evaluate their pro-inflammatory effects in THP-1 and A549 cells. Both cell lines responded to UFP producing interleukin-8 (IL-8), with wood log UFP being more active compared to pellet UFP. With the exception of higher effect observed with beech wood log UFP in THP-1, the ability of soft or hard woods to induce IL-8 release was similar. In addition, on weight mass, IL-8 release was similar or lower compared to diesel exhaust particles (DEP), arguing against higher biological activity of smaller size particles. UFP-induced IL-8 could be reduced by SB203580, indicating a role of p38MAPK activation in IL-8 production. The higher activity of beech wood log UFP in THP-1 was not due to higher uptake or endotoxin contamination. Qualitatively different protein adsorption profiles were observed, with less proteins bound to beech UFP compared to conifer UFP or DEP, which may provide higher intracellular availability of bioactive components, i.e. levoglucosan and galactosan, toward which THP-1 were more responsive compared to A549 cells. These results contribute to our understanding of particles emitted by domestic appliances and their biological effects. [ABSTRACT FROM AUTHOR]

Aerosol mass (PM 10 and PM 2.5 ) and chemical composition recorded in the 2009 at the rural background station of Monte Martano (MM, Central Italy) are presented in this work. The site, located at 1100 m (asl), features relatively low aerosol mass levels, due to the little influence of local anthropogenic pressure, and is influenced mainly by long-range transport phenomena. Chemical composition of PM 10 and PM 2.5 at MM is characterized by high levels of organic matter (OM), sulfates and nitrates, followed by crustal material, and ammonia. Sea Spray and elemental carbon (EC) accounted for a minor part of the total PM mass. The mass trends (PM 10 and PM 2.5 ) and chemical characteristics (OC, EC, major ions, trace elements) are compared with those of other similar sites in Europe and discussed in the framework of an extensive analysis of back trajectories (BT). As a result, three main advection routes to Central Italy (Northern Africa, West Mediterranean and Eastern Europe) have been individuated on the basis of the BT analysis and show significantly different PM 2.5 /PM 10 and OC/EC ratios. Major ions and trace elements trends are also discussed within this framework, showing that annual averages are more influenced by long-range transport from Eastern Europe, which is the prevalent advection route to MM (and Central Italy) also according to BT analysis. Finally, the data collected allowed to estimate the impact of Saharan dust on PM 10 which amounted to 22 μg m − 3 per intrusion event (22 events). The impact on PM 2.5 resulted in 11 μg m − 3 per intrusion event. [ABSTRACT FROM AUTHOR]

Abstract: This study aims to characterize PM from the open burning of bonfires as well as detect a series of useful tracer species for source apportionment studies. Total suspended particulate (TSP), PM10 and PM2.5 were collected before, during, and after St. Joseph's Eve (18th of March). On this day, several bonfires are lit throughout the study area. Levoglucosan (Lvg), OC, EC, PAHs, soluble ions, and some metals (Al, Cd, Cu, Ni, and Pb) have been determined in each fraction. Results show that the contamination of the area is similar to what is generally found in suburban areas. The fine fraction makes the highest contribution to PM. This fraction is mainly related to compounds composing the PM secondarily formed, while the coarser fractions are associated with natural matrices. The bonfire event is an important source of particulate. All the combustion markers determined in PM2.5 (EC, OC, PAHs (except for Flu and Pyr), K+, Cl−, and Lvg) register a higher concentration. Lvg/OC ratio confirms higher wood smoke emissions during these days. Both the concentration and the compound profile indicate a different origin of PAHs in the atmosphere. The highest concentration of K+ and OC in TSP confirm the contribution of open fire, as well, to this fraction, which can be ascribable mainly to combustion ash. Nitrates and sulphates also show a higher concentration in the PM10-TSP fraction. Surprisingly, there is also an increase in the concentration of components not usually considered combustion markers, i.e. Pb and Al in PM2.5. This is probably ascribable to their bioaccumulation. In conclusion, Lvg, OC, PAHs, Al, and Pb can be used together as specific markers of bonfires to identify this source of particulate matter. [Copyright &y& Elsevier]

Abstract: The use of residential wood combustion represents an important renewable energy source, but it contributes in a considerable way to atmospheric particulate matter (PM) concentration in urban as well as in rural sites. Moreover, recent studies pointed out wood burning as an important source of PAH. In the present work, the influence of wood combustion on PM was studied, investigating its contribution to the carbonaceous PM fraction and to benzo(a)pyrene (B[a]P) and polychlorodibenzo-p-dioxins and polychlorodibenzofurans (PCDD/F) concentrations, using levoglucosan as a marker. PM10 samples were collected daily for six months in two sites located in Piemonte (Northern Italy): Torino and Susa. Composite monthly samples were chemically characterized, analyzing the concentrations of levoglucosan, B[a]P, PCDD/Fs, organic carbon (OC), elemental carbon, major anions and cations, and metals. PM and OC concentrations were almost twice in Torino with respect to Susa, while levoglucosan and B[a]P concentrations were almost comparable at the two sites. Therefore, wood combustion affects more Susa than Torino. Concentrations of B[a]P and levoglucosan were highly correlated in both sites. Using the macro tracer method and the emission factors reported in literature, the wood combustion percentage contribution to B[a]P concentration was estimated and resulted as the main source in both sites. The levoglucosan to soluble potassium ratio was higher in Torino with respect to Susa, indicating that combustion plants with different efficiency are used at the two sites. PCDD/F concentrations were higher in Torino than in Susa. [Copyright &y& Elsevier]

Abstract: In this work Positive Matrix Factorization (PMF) was applied to 4-hour resolved PM10 data collected in Milan (Italy) during summer and winter 2006. PM10 characterisation included elements (Mg–Pb), main inorganic ions (NH4 +, NO3 −, SO4 2−), levoglucosan and its isomers (mannosan and galactosan), and organic and elemental carbon (OC and EC). PMF resolved seven factors that were assigned to construction works, re-suspended dust, secondary sulphate, traffic, industry, secondary nitrate, and wood burning. Multi Linear Regression was applied to obtain the PM10 source apportionment. The 4-hour temporal resolution allowed the estimation of the factor contributions during peculiar episodes, which would have not been detected with the traditional 24-hour sampling strategy. [Copyright &y& Elsevier]

Abstract: N-doped TiO2 nanocrystals were successfully synthesized by a controlled sol–gel reaction at pH 9 followed by calcinations at 400°C. Triethylamine was used to modulate the N content of the samples. The photocatalytic activity was tested using a solar irradiation source with regard to two different pollutants: NO x (in the gas phase) and methylene blue (MB), deposited onto the oxide film. In the case of MB degradation the disappearance of the (MB) blue colour was measured directly onto the solid, by means of UV–vis-NIR diffuse reflectance spectroscopy. The final mineralization of the organic molecule was assessed by COD determinations. All N-doped samples produce a better removal of both pollutants than the undoped and commercial samples. By coupling structural (by X-ray synchrotron radiation) and morphological (HRTEM, BET, granulometry) characterizations with spectroscopic analyses (EPR and XPS), the presence of paramagnetic centers, defects, edge dislocations and surface states is appreciated and found to affect the material photocatalytic behaviour. [Copyright &y& Elsevier]

Abstract: Fireworks are one of the most unusual sources of pollution in atmosphere; although transient, these pollution episodes are responsible for high concentrations of particles (especially metals and organic compounds) and gases. In this paper, results of a study on chemical–physical properties of airborne particles (elements, ions, organic and elemental carbon and particles size distributions) collected during a fireworks episode in Milan (Italy) are reported. Elements typically emitted during pyrotechnic displays increased in 1h as follows: Sr (120 times), Mg (22 times), Ba (12 times), K (11 times), and Cu (6 times). In our case study, Sr was recognised as the best fireworks tracer because its concentration was very high during the event and lower than, or comparable with, minimum detection limits during other time intervals, suggesting that it was mainly due to pyrotechnic displays. In addition, particles number concentrations increased significantly during the episode (up to 6.7 times in 1h for the 0.5

A sol–gel reaction starting from Si and Zr alkoxides, in water–ethanol mixtures, was employed to obtain praseodymium doped zirconium silicate powders (zircon).The reactions were performed by modulating both: (a) the amount of praseodymium salt in the starting mixture and (b) the speciation of the mineralizers; chloride and fluoride salts of monovalent (Na+, Li+) and divalent (Mg2+) were tested.The products of the sol–gel reaction were calcined either at 1000 °C or at 1200 °C. The samples were characterised by X-ray diffraction, SEM micrographs, EDX analyses and diffuse reflectance spectroscopy; the colour of the pigments was characterized on the grounds of the Commission Internationale de l’Eclairage (CIE) standard procedure (CIE L*a*b* measurements). Results from the structural, morphological and optical characterisations are examined and cross-compared to produce a consistent picture of the key factors leading to the formation, growth and optical properties of the reaction products. [Copyright &y& Elsevier]

In the last decades, many researchers investigated the relation between environmental pollution and the degradation phenomena on the built heritage, because of their rapid increase and growing harmfulness. Consequently, the identification of the main pollution sources has become essential to define mitigation actions against degradation and alteration phenomena of the stone materials. In this way, the present paper is focused on the study of the effect of air pollution on archaeological buildings in Historic Cairo. A multi-methodological approach was used to obtain information about the chemical composition of examined black crusts and to clarify their correlation with the air pollution, specifically the heavy metals and the carbonaceous fraction, their main sources, and their impact on the state of conservation of the studied sites. All specimens were characterized by polarized optical microscopy (POM), X-Ray Diffraction (XRD), Electron Probe Micro Analyser coupled with energy dispersive X-ray spectrometry (EPMA-EDS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and Thermo-gravimetric analysis (TGA). The study conducted on heavy metals and carbonaceous fraction showed that the greatest contribution of the accumulation of pollutants is attributable to vehicular traffic and industrial activities, the main polluting sources in Cairo city. Furthermore, the comparison with other studies conducted on the carbonaceous fraction in the black crusts coming from both European and non-European cities, has allowed to discriminate the contribution of the primary and secondary polluting sources. Finally, the correlation of the data obtained on the heavy metals and the carbonaceous fraction allowed to formulate important hypothesis about the processes of sulphation. Unlabelled Image • Black crusts from Cairo have been analysed by several techniques. • The effect of urban air pollution on the monuments of Cairo has been investigated. • The methodology allowed identification of pollution sources in the black crusts. [ABSTRACT FROM AUTHOR]

• Glass and marble surface hydrophobicity was modulated by applying Si-based coatings. • Polysiloxane additivated-commercial Alpha and Bluesil showed good hydrophobicity. • The silanization process by using trichloromethylsilane (TCMS) led to θ W > 140°. • TCMS was the most performing in terms of reduced absorbed water and vapor permeability. • Both TCMS and the additives-modified on marble substrate showed high UV stability. Hydrophobic polymers applied on hydroxylated surfaces increase their durability against undesired weathering processes. The achievement of a certain degree of surface hydrophobicity (reducing the water permeation) constitutes one of the main research focuses. Herein, two commercial Si-based resins (e.g. Alpha®SI30 and Bluesil®BP9710), directly applied on both glass and Carrara marble substrates, and a silanization process by using trichloromethylsilane (TCMS) were adopted. Contact angle measurements together with hysteresis determination and Surface Free Energy (SFE) were carried out to evaluate the hydrophobic features. Hence, since only in the case of TCMS a good hydrophobicity was achieved (θ around 150°), two commercial polysiloxane-based additives (e.g. TegoPhobe 1500 N and TegoPhobe 1650) were added respectively to Alpha®SI30 and Bluesil®BP9710, according to their chemical compatibility. These auxiliary substances allowed to decrease the wettability features of either glass or marble. Furthermore, since all the investigated coatings could be used as stone materials protective agents, water capillary absorption and vapor permeability tests were performed. Also in this case, TCMS revealed to be the most performing one among the adopted silane-based resins, thanks to the drastic reduction of absorbed water and the decrease of vapor permeability within the threshold value of 50%. Finally, the coatings stability was evaluated by accelerated ageing tests. [ABSTRACT FROM AUTHOR]