## 2 Material and Methods
### Methodology
#### 2.2.3 Microclimatic, Indoor Air Quality, and Biological Monitoring
In addition, a comparative analysis was carried out with the Sebera's isoperm diagram of the cellulose of books kept in bookcases K0 and K1. This type of diagram was calculated using temperature and relative humidity (measured every 15 min from May 2021 to May 2022) as inputs. It represents, for cellulose molecules, a set of curves of equal durability, called isoperms, making reference to the reaction rate at T = 20 \({}^{\circ}\)C and RH = 50%, which \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Instrument** & **Measured Parameters** & **Measuring Range** & **Accuracy** & **Position** \\ \hline \multirow{7}{*}{Testo 160 IAQ + Testo 160 E (external probe)} & Air temperature (\({}^{\circ}\)C) & \(-10\div+50\)\({}^{\circ}\)C & \(\pm 0.5\)\({}^{\circ}\)C & \\  & Relative humidity (\%) & 0 \(\div\) 100\% & \(\pm 2\)\% & \\ \cline{1-1}  & Air pressure (mbar) & 600 \(\div\) 1100 mbar & \(\pm 3\) mbar & \\ \cline{1-1}  & CO\({}_{2}\) concentration (ppm) & 0 \(\div\) 5000 ppm & \(\pm 50\) ppm & Bookcase “K0” \\ \cline{1-1}  & Illumination (lux) & 0 \(\div\) 20,000 lux & \(\pm 3\) lux & \\ \cline{1-1}  & Cumulative illuminance (lux) & calculated & & \\ \cline{1-1}  & UV radiation (mW/m\({}^{2}\)) & 0 \(\div\) 10,000 mW/m\({}^{2}\) & \(\pm 5\) mW/m\({}^{2}\) & \\ \hline \multirow{7}{*}{Testo 160 THL} & Air temperature (\({}^{\circ}\)C) & \(-10\div+50\)\({}^{\circ}\)C & \(\pm 0.5\)\({}^{\circ}\)C & \\ \cline{1-1}  & Relative humidity (\%) & 0 \(\div\) 100\% & \(\pm 2\)\% & \\ \cline{1-1}  & Illuminance (lux) & 0 \(\div\) 20,000 lux & \(\pm 3\) lux & Bookcases “F0” and \\ \cline{1-1}  & Cumulative illuminance (lux) & / & / & “K1” \\ \cline{1-1}  & UV radiation (mW/m\({}^{2}\)) & 0 \(\div\) 10,000 mW/m\({}^{2}\) & \(\pm 5\) mW/m\({}^{2}\) & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Monitoring features (from the technical data sheets). Figure 3: Instruments and their installation in the new monitoring system. will set the baseline with a value of 1. The isoperms are lines of constant durability and their value represents a lifetime multiplier: isoperm 10 means that the climate conditions (temperature and relative humidity) that correspond to the line will increase the lifetime of the cellulose by a factor of 10, in comparison with isoperm 0.1 and the others on the right of line 1. In fact, the area to the right of isoperm 1 year represents conditions for a shorter life of cellulose molecules, compared to the reference. On the contrary, the microclimate on the left of this line will extend the lifetime as indicated by the multipliers on the side of each line [19]. Similarly, indoor air quality was also examined in terms of CO\({}_{2}\) concentration. Based on the data observations, an empirical method was followed to understand when to open windows during the most crowded events. Data observations showed that many institutional meetings took place in winter and, when these involved a great number of people, the CO\({}_{2}\) values increased and exceeded the limit value of 1000 ppm. During this type of event, the windows were kept closed until the end of the event for intervals varying from a few minutes to one hour. Based on this information, the most relevant events were analysed, and a method was established to evaluate the variations that would have been obtained if the windows had been opened. This method involved only natural ventilation obtained by opening the windows for human comfort and it was based on the CO\({}_{2}\) readings on the wi-fi sensor's display in real time. This aspect shows the importance of the continuum monitoring system. As already expressed, for all materials, the indoor microclimate should be continually controlled also in order to reduce or eliminate the risk of biological attack by fungi, bacteria, or other parasites.