Pollution monitoring in storage and display cabinets: carbonyl pollutant levels in relation to artifact deterioration

The concentrations of four organic carbonyl compounds — methanal (formaldehyde), methanoic (formic) acid, ethanal (acetaldehyde) and ethanoic (acetic) acid — have been quantified in display and storage cabinets in museums in Glasgow, Edinburgh, London and Amsterdam. The cabinets investigated were selected because significant deterioration of a wide range of artifacts had occurred as a result of carbonyl pollutants liberated by the cabinet materials. Cabinet pollutant levels in the following ranges were observed: methanal c.l0-380ppb, methanoic acid <0.3-c.60ppb, ethanal c.5-85ppb, ethanoic acid c.25-750ppb. Ethanoic acid was usually the predominant pollutant present. The identity of efflorescence/corrosion products on metals (bronze and lead), ceramics, limestone and molluscs is discussed in relation to the nature and concentration of the pollutants. The effectiveness of palliative measures — increased ventilation, wood sealants and barrier foils — is assessed on the basis of the results.