## 3 Results and Discussion
### The Determination of the Microclimate Characteristics
Thus, although high values are sporadic, the cumulative effects of periodic increases in CO\({}_{2}\) can contribute to the progressive degradation of minerals, especially in the presence of constant high levels of RH, which facilitate chemical reactions [61]. Fine and coarse particles (PM\({}_{2.5}\), PM\({}_{10}\)) can act as abrasive agents, leading to the erosion of mineral surfaces and deposition of chemicals that can react with rocks [62]. VOCs and HCHO can lead to chemical reactions that form organic acids, accelerate the alteration of minerals, and cause the growth of microorganisms that contribute to biodegradation [63]. At the same time, the photooxidation process is activated by natural light and involves chemical reactions that break down organic and inorganic matter. This can lead to rock surface chemical and physical modification, making them brittle and more susceptible to erosion [64]. International standards regulate the concentrations of PM\({}_{2.5}\), PM\({}_{10}\), VOCs, and HCHO to protect human health, such as those established by the World Health Organization. However, specific standards for protecting rock integrity are less common,  
Figure 8: The values obtained for the T, RH, and CO\({}_{2}\) indicators during the period of April–June 2024 inside the rupestrian church. and general recommendations include keeping concentrations of these pollutants as low as possible. In the case of NL, international standards indicate that for less sensitive objects, such as metal, ceramics, stones and glass, they can be continuously exposed to an illumination of up to 300 lux without affecting their integrity [65]. PM2-5 recorded an average value inside the church of 4.2 \(\mathrm{\SIUnitSymbolMicro m}\)/\(\mathrm{m}^{3}\); in its immediate vicinity, the values were 6.4 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\). The maximum values reached 8 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) indoors and 12 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) outdoors, with the minimum being 0 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) indoors and 2 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) outdoors. Regarding the spatial distribution of PM2-5 within the church, the highest average values over the entire monitoring period are identified at the entrance to the church (between 5.2 and 5.8 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\)) and in the first room within it, because in the second room, the values reach a maximum of 4.3 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) and a minimum of 3 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) (Figure 9). In the case of PM10, the average values were 8.9 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) indoors and 12.8 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) outdoors, with maximum values of 15 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) and 24 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) and minimum values of 1 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) and 4 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\), respectively. The spatial distribution of this indicator follows the evolution of coarser particles (PM2-5), with averages ranging between 10.1 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) and 10.5 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) at the entrance to the church, and a downward evolution of the concentration up to the second room, where the maximum was 8.7 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\), and the minimum was 7 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{m}^{3}\) (Figure 9). Regarding the co-concentration of VOCs, the indoor average during the analyzed period was 1.24 \(\mathrm{mg}\)/\(\mathrm{m}^{3}\), with a minimum of 0.33 \(\mathrm{mg}\)/\(\mathrm{m}^{3}\) and a maximum of 3.78 \(\mathrm{mg}\)/\(\mathrm{m}^{3}\). The exterior showed an average value of 1.62 \(\mathrm{mg}\)/\(\mathrm{m}^{3}\), with a minimum of 0.78 \(\mathrm{mg}\)/\(\mathrm{m}^{3}\) and a maximum of 4.11 \(\mathrm{mg}\)/\(\mathrm{m}^{3}\).