Lorraine Gibson

University of Strathclyde

WHAT DO THE NUMBERS MEAN ?

ABSTRACT

There are numerous ways to assess the quality of indoor air. The tests range from simple methods that provide subjective, qualitative assessments of indoor air, to highly sophisticated, expensive on-line methods for the determination of specific pollutants. In the museum environment, which type of test is necessary to ensure we are doing 'the best' to preserve and protect our valuable collections ? During the presentation, the range of sampling methods currently used in museums will be summarised, outlining the perceived advantages and limitations of each.

The choice of whether to use one technique over another depends simply on the questions which have to be answered in the sampling regime. If screening of cabinets for the possible presence of pollutants is the aim, then simple colourimetric tests suffice. However, if a corrosion problem has been observed inside a display case, then the source and identity of the pollutant must be ascertained to eliminate it from the microenvironment. This would require implementation of more sophisticated sampling regime that provides quantitative, selective information.

Even when accurate numbers are obtained, and we are sure we have 'contaminated' environments, what do the numbers actually mean ? In addition to the concentration of the pollutant, we need to understand what this concentration means in terms of damage to our stored artefacts. We need to think of the pollutant's deposition velocity, the accumulated flux, the air movement inside the case, the environmental conditions such as temperature and relative humidity etc., in order to assess the situation properly.

There is a need for further research to determine the synergistic effects of all the parameters involved in pollution-induced material damage. This should take the form of laboratory and phenomenological studies.

Lorraine Gibson
Dept. of Pure and Applied Chemistry
University of Strathclyde
Glasgow G1 1XL
U.K.
e-mail: lorraine.gibson@strath.ac.uk