Comparison of Preventive Conservation Guidelines for Particulate Matter and Lighting in Heritage Libraries

The opportunity left by the COVID-19 lockdown gave institutions time to evaluate the impact of tourism on historical museums. However, the lack of a comprehensive analysis of the current conservation guidelines for lighting and particulate matter makes its assessment not so straightforward. Therefore, the present gap was addressed by reviewing and discussing preventive conservation guidelines for those two parameters and their application. Guidelines’ approaches were compared by evaluating the monitoring data in two historic libraries. Illuminance and particulate matter were measured before and during the lockdown to determine how tourism affected measurement results. While there are sufficient guidelines for lighting, there is a need to develop guidelines that assess and mitigate problems concerning particulate matter in cultural collections. Moreover, almost all guidelines were sensible to the operational changes introduced during the lockdown, of which two were considered more suitable for use in historic libraries. The direct relationship between tourism and particulates was reported (at least 28% reduction), while an indirect impact was observed (59% reduction) for lighting. In case of poor metrics compliance, the present study proposes an action plan based on literature findings for each parameter to address a compromise between tourism and collections preservation.