A procedure for identifying chemical and biological risks for books in historic libraries based on microclimate analysis

The study presents a new procedure for identifying possible risks for books kept in historic libraries. It is addressed to all those historic libraries where large collections of old and rare books are stored and preserved. These libraries were rarely used by people, but, nowadays, many of them have become touristic attractions. Consequently, their indoor microclimate may have changed, possibly leading to risks for books conservation. The proposed methodology is based on an intensive monitoring campaign, followed by an in-depth data analysis. Handy indices are also proposed to guide the researchers in the identification of possible risks. Problems related to too-high daily or spatial hygrothermal variations or problems related to specific risks (e.g., biological or chemical risks) can be identified. If a problem is observed, the identification of the most suitable solutions is more straightforward. The application of the proposed procedure to a real case study (the Baroque Library of the University of Coimbra, Portugal) has highlighted its handiness. A 6-month monitoring campaign and its consequent data analysis has pointed out potentially risky situations. Thus, measures should be taken to avoid books damage. Primarily, local actions are suggested.