IAQ 2000, Presentation 17:

Jonathan Ashley-Smith

Victoria and Albert Museum, London




The title "Epidemiology of Museums" was suggested to me and I failed to change it in time, so it may not reflect the main thrust of this short paper. The subject that I will more nearly talk about was suggested by another of the organisers. This was the application of a cost-benefit approach to the introduction of standards for indoor air quality in museums.

Epidemiology is the study of epidemics. In medicine an epidemic is a disease prevalent among a community at a particular time, produced by some special cause not usually found in that locality. In a broader sense Epidemiology is a study of the appearance and behaviours of populations, aimed at determining whether any specific environmental factor tends to have a detectable effect on a significant proportion of that population. It is possible to identify components of indoor air that have some effect on the appearance and longevity of some objects inside museums. So taking the world population of the inanimate contents of museums it is reasonable to take an epidemiological approach.

Two basic rules are:

The behaviour of the whole population tells you nothing about the behaviour of one individual.

The behaviour of one individual cannot help you predict the behaviour of the whole population.

I will have to break the second rule and make some generalisations based solely on my own experience which is limited to one individual museum, the Victoria and Albert Museum in London. The main site of the V&A is a large building, constructed over a long period from the mid 1800s to the present day. Its outer surface is marked by a large number of doors, windows, light-wells, sky-lights and diverse roofing finishes. This porous structure is placed in a part of London that happens to have the highest levels of road-side pollution in the UK. Less than 10% of the gallery spaces are served by air handling facilities designed to remove pollutants. The trustees and director of the V&A are keen to promote the policies of New Labour which suggest that a greater emphasis should be placed on access than on preservation. Last summer the trustees passed a resolution that open display ( rather than display behind glass in a vitrine) should be the norm. The current enthusiastic interpretation of access is that there should be absolutely no barrier between objects and people. Although this definitely does shift the emphasis away from preservation It is difficult to argue that it is in contravention of the UK Museums Association definition:

"Museums enable people to explore collections for inspiration, learning and enjoyment. They are institutions that collect, safeguard and make accessible artefacts and specimens, which they hold in trust for society." ( my underlining)

So, for a great part of the V&A collections, far more pressing worries than pollutant gases in indoor air could be the effects of touching ( including theft) and the effects of use ( Fig 1), In terms of balancing risks it should be noted that at least one aggressive component of indoor air ( acetic acid) really only becomes a problem when there is a barrier between visitor and object.

Fig. 1
Figure 1

The Behaviour of Museums

The subject of IAQ with its attendant costs and benefits needs to be put into the context of observations about museums in general.

Figure 2 shows a graph applicable to a number of museum phenomena. The horizontal axis shows increasing time starting at a point about 100 years ago. The present date is shown by the vertical line marked "now". The vertical axis marked "numbers" could represent numbers of :

Museums- the idea of centrally held publicly accessible collections is quite recent. The number of museums increased dramatically in the last quarter of the 20th century and then began to decline due to lack of interest and finance. These days museum closures are more frequently, though less publicly, reported than new openings.

Visitors- interest in museums, especially art museums, and particularly decorative art museums, is declining. Last year visitor numbers at the V&A and at 'Tate - old fashioned' were down by 16%.

Objects- if politicians, who speak about making museums more efficient through the strategic use of the auction house and the skip, get their way, the decline could be dramatic.

Funds- Government funds for National Museums have been declining in real terms for some years. The V&A today has a grant that is 25% lower than ten years ago.

It is in this environment that the balance of access and preservation is being judged. It is in this light that the costs of increased mechanical or passive control for the alteration of indoor air quality must be assessed.

Fig. 2   Figure 2

The Introduction of a Standard

There is a lot of talk about standards and whether they are in fact different to guidelines. People are afraid of standards because they tie you down and can be used as offensive weapons against an individual point of view. The reverse argument is that they tie your adversaries down and can be used as a defensive weapon against them. Either way it has to be decided whether the aim of introducing standards is generally to decrease the attack by pollutants on objects of cultural value or expressly to specify numerical targets that are independent of local conditions or constraints. Apart from a slightly greater sense of freedom, guidelines do not release you from this decision. The introduction of either standards or guidelines must be shown to have a net benefit.

Figure 3 shows a sensitive way of detecting any change in a range of measurable factors to do with museum performance. The horizontal axis shows increasing time. The introduction of, and compliance with, a standard for improved IAQ is marked by a vertical line at some specified date in the immediate future. The vertical axis marks positive or negative changes to the factor in question. No change whatsoever would be shown by a horizontal line starting at zero on the vertical axis. Any continuous change is shown as a horizontal line at some other value. Any discontinuity in the rate of change would be seen as a step between two horizontal lines.

The red line shows a continuous slow decline in any number of museum performance indicators: Number of visitors, number of school parties, income from the shop, income from central government , income from sponsors. It probably also represents the overall state of the collection, and even the total value of the collection. All of these are completely independent of compliance with a standard. Even if compliance did lead to a lowering of the concentration of some airborne pollutants this would only be noticed as a very slight change in the rate of decay in the collections. The effect of this on public access and enjoyment in the immediate future is negligible if not actually zero.

Fig. 3   Figure 3

Figure 4 shows one possible discontinuity. The small number of grants currently available for capital projects from the Heritage Lottery Fund might increase slightly because compliance with standards tends to ease the stage of the process where the environmental advisor is involved. This graph would then also respond to the change in running costs.

Fig. 4   Figure 4

The Need for Research

This meeting is not only about the need for standards but about possibilities for research funding. It is possible to carry out a cost-benefit assessment for a research proposal just as easily as for the introduction of a standard. There are two reasons why a cost-benefit approach might not lead to the sudden release of funds for research into IAQ in museums. Firstly a slight decrease in pollutant levels is unlikely to have a provable effect on any of the criteria that are currently used as museum performance indicators. Secondly so much good work has already been done that it becomes increasingly expensive to make a marginal improvement.

This is shown in Figure 5. The costs of obtaining new information continue to rise with time yet the increase in valuable knowledge resulting from continued research in a specific area tends to tail off after a while. It is now perfectly possible to construct a very-low-exchange-rate display case in which the only non-inert material is the object displayed. Future research into the mathematical modelling of display case environments is unlikely to result in a sensational improvement. Research is only necessary to predict the result of poor management decision-making or to minimise the damage caused by designers who insist on using cheap or dramatically different materials. Only if the change in value of the whole world stock of museum collections is taken into account is there justification for further extensive research. And then this should be carefully planned with a limited number of partners and extensive communication of results.

Fig. 5   Figure 5

The necessary stages in any Cost Benefit Analysis (CBA) are shown in Fig 6. The most important step for museum collections is step 6, the calculation of net present value. This is the estimation of the value now of the expected future streams of costs and benefits, ( for a fairly clear and simple explanation of this see my book "Risk Assessment for Object Conservation"). If the benefits continue to be much greater than the costs, well into the future, then the net present value is high.

The tarnishing of silver gives a good example. In an environment where tarnishing is rapid, the cost of cleaning and protection continues to be high and the benefit to the viewing public of dirty silver objects is traditionally considered low. The annual cost of failure of protective measures for silver objects at the V&A is around £20,000 in cleaning expenses. Suppose that some mechanism was employed that reduced this by 90% it would be reasonable to expend at least £100,000 on plant that had a lifetime of 30-50 years ( the NPV of saving the cleaning costs but probably incurring new maintenance and running costs). However since the Museum has already recently invested in new showcases, which have not dramatically reduced the rate of tarnish, this money would have to be spent on unobtrusive modifications. and would need compelling evidence that the 90% saving would be made. Given the small likelihood of affordable new research quickly leading to confidence in the outcome of retrofitting existing cases the museum will probably accept the cost of cleaning for the time-being.

Figure 7 shows a flow-chart for the CBA approach adopted by The National Acid Precipitation Assessment Program ( NAPAP). By each of the stages is a letter which indicates whether in my view the process involves observation, measurement, calculation, development of theory or value. Although some of the stages rely on hard science there are just as many that require soft research into aesthetic values and the relationship between condition and continuing benefit. The same analysis is valid for indoor pollution and it suggests that application for research funding could equally be made to the Arts and Humanities Research Board as to any of the traditional science research funders. This research might possibly lead to a better valuation of changes in the state of collections which might in turn justify the expense of further scientific research.

Fig. 6

Figure 6

Fig. 7

Figure 7

Jonathan Ashley-Smith
Head of Conservation
Victoria and Albert Museum
South Kensington
London SW7 2RL, UK

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