Voc Emissions from Canvas and Acetic Acid Deposition to Canvas and Glass

The protection of paintings and other objects in collections is a major concern for museum administrators, conservators and national authorities. Artwork may get damaged by accumulation of air pollutants inside protective enclosures due to emissions of volatile and semi-volatile compounds from the exposed objects or from the enclosure itself. Relatively little is known about emissions and deposition of volatile organic compounds (VOC) in the museum environment. We used stateof-the art on-line instrumentation to measure the emissions of small carbonyls (formaldehyde, acetaldehyde, acetone) and carboxylic acids (formic acid, acetic acid, propionic acid) from three different canvas samples provided by the Tate Gallery in London. In addition, we measured the deposition velocity of acetic acid to the three types of canvas and to an activated carbon cloth. In a simple experiment, we confirmed that acetic acid efficiently adsorbs and sticks to establish a layer on a clean glass surface. Finally, we performed a gas chromatographic analysis of a film collected on the inside of a window of a museum exhibition showcase and found a variety of organic compounds including a series of carboxylic acids. Installing and periodically exchanging activated carbon cloths (or other adsorbent media) inside a museum enclosure appears to be an efficient way to reduce volatile organic acid concentrations.