## 3 Results and Discussion
### Microclimatic and Biological Monitoring
#### 3.1.1 Indoor Air Temperature and Relative Humidity
However, the values of both levels are inside the recommended range for the entire annual period. A weekly analysis was carried out for the representative periods of the seasons. In general terms, relative humidity values did not exceed the suggested maximum value (60%) and daily fluctuations were limited, as reported in Table 9. During summer, the trends on both levels were similar, while in winter the floor level presented lower values, owing to heating by the radiators. Finally, a comparative analysis of indoor air temperature and relative humidity was carried out: Figure 8 shows a [PERSON]'s isoperm diagram of the cellulose of books kept in bookcases K0 and K1, calculated using temperature and relative humidity values of an annual period (from May 2021 to May 2022). To facilitate comprehension of the graph, the temperature and relative humidity readings are coloured to highlight the seasons: blue dots for Winter (the interval in which the heating is on, from 15 October to 15 April), green dots for Spring, red dots for Summer and orange ones for Autumn. For both positions, the most negative period corresponds to the warm seasons, in particular the entire summer season and half of the autumn and spring readings. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & **1 May 2021** & **1 September 2021** & **18 October 2021** & **16 April 2022** \\  & & **31 August 2021** & **17 October 2021** & **15 April 2022** & **31 May 2022** \\  & **Heating System** & **OFF** & **OFF** & **ON** & **OFF** \\ \hline \multirow{5}{*}{**Spring**} & T\({}_{\text{max}}\) (\({}^{\circ}\)C) & 33.9 & 27.1 & 31.6 & 23.6 \\  & T\({}_{\text{ave}}\) (\({}^{\circ}\)C) & 24.1 & 24.0 & 19.9 & 19.3 \\  & T\({}_{\text{min}}\) (\({}^{\circ}\)C) & 17.3 & 19.1 & 11.6 & 17.0 \\  & \(\Delta\)T\({}_{\text{24 max}}\) (\({}^{\circ}\)C) & 5.5 & 1.4 & 3.8 & 3.8 \\  & \(\Delta\)T\({}_{\text{24 ave}}\) (\({}^{\circ}\)C) & 0.5 & 0.5 & 0.7 & 0.9 \\ \hline \multirow{5}{*}{**Spring**} & T\({}_{\text{max}}\) (\({}^{\circ}\)C) & 33.2 & 26.6 & 31.4 & 27.1 \\  & T\({}_{\text{ave}}\) (\({}^{\circ}\)C) & 24.3 & 23.7 & 19.7 & 19.3 \\ \cline{1-1}  & T\({}_{\text{min}}\) (\({}^{\circ}\)C) & 16.9 & 18.5 & 10.8 & 16.6 \\ \cline{1-1}  & \(\Delta\)T\({}_{\text{24 max}}\) (\({}^{\circ}\)C) & 6.1 & 1.6 & 6.1 & 6.1 \\ \cline{1-1}  & \(\Delta\)T\({}_{\text{24 ave}}\) (\({}^{\circ}\)C) & 1.7 & 0.6 & 1.2 & 1.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Analysis of the monitoring campaign data (indoor air temperature). Figure 7: Indoor and outdoor relative humidity, annual trend (hourly averaged data). This type of diagram is specific for cellulose, but the books kept in these bookcases may also be composed of other organic materials, not only paper. However, the graph represents a useful instrument for simultaneously analysing the temperature and relative humidity of the environment that hosts the books. To complete the analysis, performance indices (PI) for temperature and relative humidity were calculated: four levels were established according to the acceptability ranges of these two parameters (Table 4). The percentage of time during which the parameters fell within the recommended values for the annual period examined was calculated [14]. The results are shown in Table 10.  
Figure 9 shows, in graphic form, the results of this analysis: in the monitoring period (from May 2021 to May 2022), more than 50% of the measured data of both positions were within level one (the acceptable range for temperature and relative humidity), but a large \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Level**} & \multirow{2}{*}{**Description**} & **PI [\%]** & **PI [\%]** \\  & & **K0** & **K1** \\ \hline
1 & T and RH within recommended ranges & 62.7 & 59.8 \\
2 & Only RH within recommended ranges & 37.2 & 40.2 \\
3 & Only T within recommended ranges & 0.0 & 0.0 \\
4 & T and RH outside recommended ranges & 0.1 & 0.0 \\ \hline \hline \end{tabular}
\end{table}