Mitteilungen des Österreichischen Staatsarchivs 39. (1986)
Archive Buildings and the Conservation of Archival Material. An Expert Meeting, held in Vienna, Austria October 30 - November 1, 1985 - THOMAS, David: Architectural Design and Technical Equipment for the Physical Protection and Conservation of Documents
Architectural Design and Technical Equipment 239 Show cases present particular problems as it is difficult to avoid the use of wood or wood-based construction materials. The use of aluminium foil is suggested as a suitable liner to protect the contents of the case from any pollutants generated by its structure. 3.2 If indoor generated pollution can be controlled by good building design and suitable working practices, the same cannot unfortunately be said of pollution coming in from outside. The main pollutants generated outside buildings are particles, ozone, nitrogen oxides and sulphur dioxide. The extent to which pollutants flow into buildings and affect their contents is dependent on a number of factors. These include the permeability of the building, how tightly it is constructed and how many doors and windows it has. Ventilation can also have a major impact; a positive ventilation system which draws in air from the outside will produce concentrations of pollutants approaching those outdoors. A system which recirculates indoor air will not tend to draw in so many pollutants. Local weather conditions will also affect the picture. In windy weather, there will be a difference in pressure between inside and outside and air will tend to penetrate the building. Similarly, in cold weather, a heated building will tend to produce a stack effect, drawing air in at the lower levels and exhausting it at the top. In hot weather, people tend to open windows 27). The levels of pollutants within buildings tend to be lower than those outdoors. This is partly because of the factors discussed above and partly because the major polluting gases tend to be absorbed by the surfaces of structures. Sulphur dioxide, for example, is readily absorbed by plaster and indoor levels tend to be about half those outside. Similarly, ozone is rapidly destroyed by organic materials and some studies have failed to find significant concentrations of ozone inside archive buildings or libraries. High concentrations have been found in buildings in Los Angeles and, curiously, in a museum in rural eastern England28 *). All these pollutants are generated naturally: sulphur dioxide and particles in volcanoes, nitrogen oxides in forest fires and ozone in the upper atmosphere. The worst sources, however, are man-made. Burning coal, oil and gas in power stations or factories will produce sulphur dioxide and in the case of coal and oil, particles. Motor vehicles produce sulphur dioxide and particles and will emit nitrogen oxides which are harmful in themselves and can be oxidised by sunlight to form ozone28). Archives which are situated in the centres of sunny towns or close to industrial areas may find that their holdings are being 21) J. E. Yocom and others Effects on Indoor Air Quality in Air Pollution 2 (The Effects of Air Pollution), ed. A. C. Stem (New York 1977) 118-120. 28) Thomson The Museum Environment 128, 245; N. S. Baer and P. N. Banks Indoor Air Pollution: Effects on Cultural and Historic Materials in International Journal of Museum Management and Curatorship 4 (1985) 12. 2S) A. C. Stern and others Fundamentals of Air Pollution (Orlando 1984) 51-52, 76-96.
