## 3 Results and Discussion
The XPS results related to that period were previously commented together with other instrumental techniques [13; 14] also taking into account online data provided by the control unit of the regional agency ARPAB on the local weather and emissions from the nearby incinerator 'Fenice' on the wind direction and strength (retrievable by the wind rose graphic) and combined microscopy and biological analysis. In these supplementary figures, the XPS results were re-proposed using the grouped components, equally shown in the pie chart of Figure 4 for the reference 0R samples, as the appropriate 'indicators' of the calcarenite decay versus time. As evident in Figure S1a-d, the new building in the nine months of exposure to the outside since its installation (July 2009) showed compositional variation of its wall surfaces, the changes of the main chemical groups in their relative intensity certainly linked to the seasonal characteristics of the year (temperature, rainfall, wind, etc. ):  
* In the first 3 months, traces of other elements are seen deposited on the west, south and east walls, consisting of sulfur, phosphorus and chlorine anions, all mass balanced by sodium counter cation, most likely coming from the incinerator fumes and transported by the winds blowing from the north. * After 3 months, it can be noted that the contribution of carbons, C-C and COx/CN, other than carbonates, has, 'on average', increased compared to the reference. This can be attributed both to the deposition of carbonaceous particles possibly contributed by the combustion process of the 'Fenice' incinerator (PTS) and/or to the presence of microorganism colonies, already localized and developed in the subsurface/inner areas, as attested by slight chromatic changes of surfaces and colored stains along some parts, porous and with interstices, of the cube walls and corroborated by SEM images (see the next sections). * The excess of carbon carbonate compared to calcium carbonate, clearly visible in all Figure S1a-d graphs, could be attributed to the formation of calcium bicarbonate Ca(HCO\({}_{3}\))\({}_{2}\), the unbalance attesting to the first form of degradation of calcite, the predominant component of calcarenite. In fact, when the calcarenite comes into contact with humidity and acid rainwater, the calcite hydrates and dissolves, forming carbonate complexes such as bicarbonate ions [25; 26]. Depending on the outdoor conditions, the main carbonate structure of calcarenite can be differently hydrated, thus leading to different H\({}_{2}\)CO\({}_{3}\)-/CO\({}_{3}\)- mixtures differently balanced by calcium, while'mixed oxides' may include flowing ions sharing the hydroxyls of the phyllosilicate structure and the oxygens of functionalized carbons and other combinations to be similarly verified in the presence of oxal acid and other metabolites due to biological activities [6; 7; 27; 28]. * Hydration and de-hydration processes could be followed by the oscillation percentage of oxygen for each wall during nine months. The oscillations could be the result of meteorological conditions favoring/disfavoring the synergistic actions of abiotic and biotic pollutants locally interacting with calcarenite surfaces. The calcarenite cube, from the moment of its installation, has certainly experienced hot but also rainy periods, as reported by the portal of the Lavello weather station ([https://www.3 bmeteo.com/meteo/lavello/storico](https://www.3 bmeteo.com/meteo/lavello/storico) (accessed on 3 July 2025), periodically accessed during experiments). The high temperature and the abundant rainfall represent the fundamental conditions for condensation phenomena to occur, which constitute an extremely efficient transport mechanism for atmospheric pollutants.