The importance of environmental parameters for the conservation of mural paintings. Specificity of the Sistine environment.

The importance of monitoring the environmental parameters inside the Sistine Chapel is highlighted by the large surface area covered by mural paintings, and the high number of daily visitors to this world famous artistic and cultural treasure. Periodic checks on the state of conservation of the frescoes required scheduled measurements and analyses that were conducted between April 2011 and January 2012. The complex instrumental study with processing of the data collected served to characterise the microclimate of the Sistine Chapel environment by means of its basic parameters and the effect of their interaction with the painted mural surfaces. This analysis determined the effective balance of air exchange between the outside and inside of the Sistine Chapel, partly regulated by the existing climate control system installed in 1994. The impact of visitors, heat sources, water vapour, carbon dioxide and dust - was measured in the same way, documenting the effects of these atmospheric components on the wall paintings. The results obtained at the end of the ten-month study disclosed an urgent need to make major improvements to air circulation and exchange rates inside the Sistine Chapel and to fit the air conditioning system with carbon dioxide and dust abatement systems to ensure continuous monitoring of the parameters listed mentioned above.