Aerobiological and Microclimatic Diagnosis In Cultural Heritage Conservation at the Palatina Historic Library In Parma (Italy)

Bioaerosol in indoor cultural heritage environments represents an hazard for cultural property, due to the biodeterioration risk, and for operator/visitors for possible infectious, allergenic and toxic effects. Microclimate play an important role in favoring the damage. We have applied at the Palatina Library in Parma an integrated monitoring approach (biological and microclimate), as a useful tool to manage biodegradation-related risks. Methods: Samplings were performed during summer and winter at different heights. Microbial airborne contamination was measured by active (CFU/m3) and passive (IMA) sampling; cultural and molecular techniques were performed. Airborne particles were counted by a laser particle-counter. Key microclimatic parameters were recorded and infrared temperature measurements of surfaces were performed. Computational Fluid Dynamics (CFD) simulations based on a multi-physics approach and applied to three-dimensional models of the studied environment integrated with experimental data were used to study the indoor microclimate conditions and the diffusion of particles. Results: A wide variability of air microbial contamination (CFU/m3, IMA) was found, with the highest values in summer. A significantly higher concentration was observed for particles ≥0.5 and ≥1.0 µm in summer and for particles ≥5.0 µm, in winter. A significantly higher concentration was observed at 1 m for particles ≥0.5 and ≥1.0 µm and for IMA. The most frequently isolated fungi were Cladosporium, Alternaria and Aspergillus. Modification of the airflow patterns and air velocity distribution were evident due to person moving inside. In the absence of imposed pressure gradients, the effect of a person moving in the buoyancy-driven flow may have a considerable impact respect to small particle. Conclusions: This interdisciplinary research represents a contribution towards the definition of standardized methods for air quality evaluation in indoor heritage environment. Studying both biological and microclimatic quality in fundamental to define adequate conservation methods and standards and to protect the health of operators and visitors.