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The work focuses on the investigation of air pollutant impacts on the ancient ramparts of the Moroccan city of Sale, part of the Project TeACH (Technologies and tools to prioritize assessment and diagnosis of air pollution impact on immovable and movable cultural heritage), which set out to understand the different types of deterioration due to pollution impact on cultural heritage in diverse sites. The part of the walls studied is the Burg al Klāb (Bastion of dogs) tower, also known as the Gate Tower, as an example of a monument in the Mediterranean Basin, built in calcarenite and exposed to a polluted environment, especially traffic. The complete characterization of the surface damage layer forming on the Burg al Klāb was performed by a range of analytical techniques, including optical and scanning electron microscopy, X-ray diffraction, ion chromatography and induced coupled plasma-optical emission spectroscopy. The results showed that the main damage factor is the deposition of atmospheric sulphur compounds, and sea salts and particles from combustion processes. The deposition of SO 2 and marine aerosols effects in formation of new minerals, such as gypsum (CaSO 4 ·2H 2 O), halite (NaCl) and thenardite (Na 2 SO 4 ) and other hydrated forms of sodium sulphates. The octagonal shape of tower and different exposition of walls to traffic roads was reflected in the results from the analyses. A decrease in lightness L* was measured passing from more protected walls to those more exposed to traffic. Sulphate, nitrate and organic carbon were also found in higher concentrations in the samples collected from the walls directly exposed to traffic. The high amount of Ca 2+ is ascribed to the calcium carbonate-rich substrate, to soil dust re-suspension and subsequent deposition onto the building surface, as well as to the long-range air mass intrusions from the Sahara. The traffic in the proximity of Tower is not only responsible for particle emissions but also for the re-suspension of dry deposited road traffic emissions and soil dust.

There is wide recognition of the pivotal role of gaseous multi-pollutants and aerosols in determining the damage encountered on monuments and built cultural heritage in European cities. The main effects of atmospheric pollution on building materials in urban areas are soiling and black crusts formation. Furthermore, anthropogenic pollutants have changed over time, and attention now focuses on the contribution to damage layer formation of particles, particularly soot/carbonaceous ones, whose importance in determining air quality in urban areas is steadily increasing. However, the analytical tools and currently available data remain inadequate to attain a correct approach to black crust characterization and identification of causes of damage: there is a pressing need to discriminate and quantify the pollutant amounts, particularly that of carbonaceous aerosols, which deposit and accumulate on monuments and building surfaces, giving rise to surface blackening. The present work makes a contribution to filling this gap by presenting data on carbon fraction speciation and concentrations, obtained from the application of a specific analytical methodology on black surface layers in different European cities. As well as providing a preliminary data base, the information obtained turn out to offer some insight into past, present and future pollutant sources contributing to the damage on the built heritage.

A proper recognition of the pollutant sources in atmospheric deposit is a key problem for any action aiming at reducing their emission, being this an important issue with implications both on human health safeguard and on the cultural heritage conservation in urban sites. This work presents the results of a statistical approach application for the identification of pollutant sources in deposits and damage layers on monuments located in different European sites: Santa Maria del Fiore, Florence (Italy), Cologne Cathedral, Cologne (Germany), Ancient ramparts, Salè (Morocco), National Museum, Cracow (Poland) and National Gallery, Oslo (Norway). For this aim, the surface damage layers on monuments and historical buildings of the selected sites were collected and analyzed, in terms of ionic and elemental composition, through application of ion chromatography and induced coupled plasma-optical emission spectroscopy. The achieved results were processed by multivariate analyses such as correlation matrix and principal component analysis in order to identify the possible origin of pollutants affecting the state of conservation of the monuments. This allowed us to assume that in all case studies the traffic emission is the main pollutant source. In the case of Ancient ramparts, Salè (Morocco), and National Gallery, Oslo (Norway), the surfaces are also under influence of marine aerosols. Moreover, concerning the Cologne Cathedral, the strong impact of the pollutants emitted by railway station was also revealed. © 2014 Elsevier B.V.

It is now well known that air pollution is responsible for the accelerated damage encountered on cultural heritage located outdoors. Although several works on atmospheric pollutants have been performed, studies of atmospheric pollutant monitoring close to monuments remain rare. In addition, the few cases reported in the literature mostly regard indoor environments. As the protection and conservation of monuments and historic buildings constitutes a priority for each country, knowledge of particle composition near monuments over time is an important issue in conservation strategies. For this reason, the atmosphere in proximity of the Florence Baptistery, located in the city centre, was continuously monitored during 2003 and 2004 by means of aerosol sampling performed close to two of the three doors of the monument. In particular, the monitoring was performed close to the North Door, realized by Lorenzo Ghiberti (1403-1424), currently utilized as the entrance to the monument, and the South Door, a masterpiece of Andrea Pisano (1330), employed as the exit for visitors. The sampling sites were characterized by different expositions to road traffic emissions. The non-carbonate carbon and soluble ionic components of the total suspended matter were measured. The data obtained is presented and discussed with the goal of contributing to the formulation of guidelines for a suitable safeguard of the built cultural heritage. © 2009 WIT Press.

It has been recognized that many modern buildings undergo rapid deterioration, especially in areas with high air pollutant concentrations. It is assumed that the deposition of gaseous multipollutants and aerosols plays a major role in causing the deterioration of monuments and built cultural heritage in European cities. While the deterioration process due to air pollutants and particle deposition is well studied in stones, particularly limestone, sandstone and granite, in the case of cement materials the subject has yet to be explored. This work focuses on the investigation of the impact of air multipollutants on concrete architecture in current urban atmospheres. The diagnosis of surface layers considering location of buildings, is a major issue in this research. To this end laboratory analyses have been preformed on samples from buildings exposed in different urban areas: Centennial Hall of 1913 (Wroclaw, Poland, close to a power station); Chiesa dell'Autostrada del Sole of 1963 (Florence, Italy, close to the motorway) and Casa Galleria Vichi of 1911 (Florence city centre). The samplings were carried out taking into account different levels and parts of the buildings, in washed out, sheltered and partly sheltered areas. The characterization of collected surface layers and cement mortar samples was performed using a range of analytical methods, including optical and scanning electron microscopy, x-ray diffraction, ion chromatography, induced coupled plasma-optical emission spectroscopy, differential and gravimetric thermal analysis and CHNSO elemental analysis. The quantitative results from the experimental work will be presented and discussed, in order to achieve an exhaustive picture of the main causes leading to concrete deterioration in the buildings under study.

The availability of a correct, accurate and reproducible analytical method for a complete carbon balance in black crusts is of major importance in understanding the effects of the interaction between atmospheric pollutants and the environment, particularly in the partitioning of pollutant sources, damage mechanism identification, and a sustainable protection of cultural heritage. The EC Project CARAMEL has among its primary goal the setting up of a suitable and reliable analytic technique able to distinguish and measure carbon fractions in damage layers, particularly elemental carbon. The presence of a significant amount of carbonate carbon and the removal of organic carbon are critical steps in the measurement of carbon compounds in black crusts. A chemical-thermal methodology for carbon analyses in black crusts was set up, whose specificity, accuracy and precision was tested on appropriate standard samples. The results obtained indicate that the methodology satisfactorily distinguishes among carbon species and allows a reliable evaluation of their quantities in damage layers.