Visually low-impacting methods for the measurement of parameters related to IAQ risk indicators in exhibition halls

Microclimate for cultural heritage plays a fundamental role in the degradation process of artefacts exhibited in museums. Generally, the Indoor Air Quality (IAQ) monitoring inside museums is based on conventional measurements of thermo-hygrometry parameters and longtime averaged measurements of atmospheric pollutants’ concentration. Unfortunately, all these approaches require electric supply and are usually characterized by a noticeable visual impact on the exhibition space, which clearly negatively affects the visitors’ experience. This paper intends to revisit and discuss a methodology (and its test application on field, to estimate the risk of damage of three artefacts displayed in an old museum of Palermo – Italy) perhaps prematurely underestimated that could usefully be re-proposed in particular contexts in which it is necessary to be careful to be as less invasive as possible, as in the case of museums housed in buildings of particular historical-cultural prestige. The discussed approach uses a non-destructive (or minimally invasive, at least) technique consisting in using two types of coupons, bi-metallic and marble ones, that allows an off-line monitoring of the indoor air aggressiveness inside museums, while avoiding consuming electricity and undesirable visual impacts on the site. Specifically, the estimated coupon damage is regarded as gauge to air aggressiveness, in order to provide an early warning of the risk of damage for the artefacts made of materials similar to those which the coupons are made of. Based on the considerations reported in the paper, the indirect evaluation of the air chemical aggressiveness through the assessment of the bi-metallic and marble coupons’ erosion seems to still candidates itself as a feasible method to be applied in complex exhibition scenes.