Publication Type:Journal Article
Source:Studies in Conservation, Volume 54, Number 1, p.49-57 (2009)
This paper aims to assess the possible impact of air pollution on works of art kept in storage at the Museum of Modern and Contemporary Art. Soiling removed during the process of conservation-restoration was analysed for its ionic content, lead, soot and polynuclear aromatic hydrocarbons. The samples were taken from four paintings: two of them had been kept in the central store within the Museum’s building since the mid-1970s or 1980s, while the other two had been stored in temporary storage in the city centre since the mid-1990s. The common characteristic of all the soiling was the predominance of sulphate and calcium. These two ions are dominant in the aerosol composition found indoors, their source being either plaster soiling and/or chemical reactions of sulphur dioxide with calcite. The excess of sulphate relative to calcium found in the two paintings kept in the central store when the outdoor air pollution was highest, suggests the air pollution impact. No excess of sulphate was found in the two paintings stored in the temporary store since the 1990s, when the outdoor air pollution of sulphur dioxide was substantionally reduced. In this case high levels of calcium were found, probably due to calcite soil and building materials.