Indoor conservation environments, such as museums, are unique places that have the main function of preserving the artworks, objects composed from different material types that constituted the artistic heritage, but also the educational, cultural and social heritage. When the collections are host in historic buildings their historical-artistic value is increased, while in contrast, the restriction of the historic building can threaten the proper conservation of artworks and hinder the museum management. A typical example is the royal palace of Capodimonte in Naples that hosts the homonymous museum. The preventive conservation, necessary to guarantee the full "enjoyment" of the works to future generations, requires the implementation of an efficacious pollution monitoring program.
With this aim, the Museo di Capodimonte hosted a prototype of an innovative multi-parameter environmental monitoring system developed under the MIUR PONa3_00363 I-AMICA project. The IEMS system (Indoor Environmental Monitoring System) was designed and realized in the framework of a collaboration between ISAC-CNR of Bologna and FAI Instruments s.r.l.. It is a mobile prototype that can continuously perform measuring program of concentration substances responsible of indoor pollution in museum environment. The "twin" IEMS system, active in Capodimonte since July 2015, consists of two single units that perform independent, indoor and outdoor measurements of traditional and innovative parameters in the museum field: T, RH, Pa, Lux (only indoor) O3, CO2, BC, PM1, PM2.5, PM10, dimensional distribution of aerosol from 0.28 to 10 μm.
Preliminary data show that in the presence of high concentrations of outdoor pollutants (particles and ozone) these can be transported inside the Museum (in the summer months) by influencing the air quality values in the exhibition rooms,; the monitoring of indoor physical parameters (T-RH) registered values not always under the thresholds requested for the preservation of cultural heritage.
Usually, in the absence of turbulence, the aerosol coarse particles settle on the surfaces, not only horizontal, and provoke films formation that could alter the visual and aesthetic perception of the artworks and cause microbial growth and biodegradation under favorable microclimatic conditions. On the contrary, fine particles are harmful since they can penetrate into microenvironments such as showcases.
The PM indoor concentration, although not negligible, is markedly lower than one measured by the outdoor IEMS, which shows worrying high values. However, the comparison between indoor and outdoor monitoring shows a good correlation between several parameters and suggests a relevant intrusion of pollutants from the outside to the inside of the museum, especially during the summer season. Thus, a better insulation of the building, as well as a rigid protocol for air exchanges is needed.