Environmental monitoring of display cases in museums to consider the impact of display cases characteristics on their inner air quality

While technical characteristics, such as material used in the construction of display cases and their dimensions are important factors in terms of presentation quality as well as attracting the attention of the visitors, they can influence the inner air quality of the display case and preservation conditions of the exhibits too. This study intends to examine the effect of the technical characteristics of display cases in 6 museums located in the cities of Tehran, Berlin, and Bombay on the interior air quality in terms of chemical composition and corrosion potentials by adopting the results obtained from the analysis ad examination of the environment.   In the course of the investigation, the manufacturing materials in the display cases were considered. Furthermore, the air exchange rate through the carbon dioxide tracer gas was measured, the concentration of gaseous pollutants (emitted from display case materials) via passive sampling by Palmes tubes and analysis of the samples by IC, HPLC and UV/visible spectrophotometer were carried out. Furthermore, the corrosive potential of the display cases was evaluated by copper, silver, and lead metal coupons. The results showed that the use of synthetic or natural materials in the construction of display cases even with low emission, acetic and formic acid, and formaldehyde might be increased in the airtight display cases with low air exchange rate over time because of accumulation of pollutants. These gaseous pollutants could damage the exhibits in the display cases. On the other hand, the dimensions of the display case are inversely proportional to the concentration of pollutants. In the same way, larger display cases show lower concentrations of pollutants. Therefore, the choice of materials and the air exchange rate of display cases play an important role in the air quality within the display case, which also affects the quality of the conservation and preservation of the exhibits.