The role of historical buildings in the biodeterioration and preventive conservation of archival heritage: the case of the Historical Archives of Palermo

Unsuitable environmental conditions can be responsible for biodeterioration phenomena on cultural collections. Historical buildings are known to be able to dampen external climatic fluctuations, reducing the impact of the outdoor climate on the indoor conditions. The growing sensitivity towards environmental sustainability, particularly in the light of climate change, requires a reflection on the role that historic buildings can play in future heritage conservation. The simulation of the environmental conditions inside buildings is an effective tool in the study of the dynamics of heat exchange. This study aims to reconstruct the future trends of indoor environmental conditions starting from the forecasted external climate. The investigation was applied to the State Archives of Palermo, housed in the 15th century convent of Santa Maria degli Angeli, where an environmental monitoring campaign started in May 2021 and is still ongoing. The results highlighted the key role of temperature on biological proliferation (insects and microorganisms) and the rate of chemical deterioration processes (cellulose hydrolysis). The global warming scenario highlighted that it is necessary to prepare right now effective measures to limit the expected increase in temperatures in the Archive, thus enhancing artworks durability as well as limiting deterioration of the historic building itself.