An upgraded automatic piezoelectric quartz crystal dosimeter for environmental monitoring in indoor cultural heritage conservation areas

In the field of cultural heritage preservation, establishing and monitoring the aggressiveness of indoor microenvironments towards materials is an essential task for conservation professionals and represents an important step in the overall definition of environmental management strategies in museums. This paper describes the assembly and operation of an upgraded device based on quartz crystal microbalances developed for monitoring the ageing of artistic materials that can be coated as thin films on piezoelectric quartz crystals. Data on the ageing rates occurring in the films during exposure in a conservation area are used to appraise that specific microenvironment in terms of risk of damage for painted works of art. This novel device, based on an earlier prototype, is now provided with on-board sensors for simultaneous measurement of temperature, relative humidity and light intensity and type. This improvement is helpful to interpret the response of such piezoelectric dosimeters and to complement their information, thus enhancing the quality of the risk assessment. Here, the potentials of the monitoring device are shown in field campaigns carried out in two of the most important museums of the city of Sمo Paulo, Brazil: a history museum (Museu Paulista) and a plastic arts museum (Pinacoteca do Estado). Using mastic varnish as a target material, it was possible to rank the degree of environmental aggressiveness of the exhibition and storage areas of the two museums and suggest that light incidence (and possibly airbourne pollutants) is the main ageing factor, at least as far as organic materials are concerned.