PROTECTION OF ARCHIVAL MATERIALS FROM POLLUTANTS: DIFFUSION OF SULFUR DIOXIDE THROUGH BOXBOARD
CHARLES M. GUTTMAN, & KENNETH L. JEWETT
Archives, libraries, and museums provide long-term storage of enormous volumes of records. Protecting these documents from degradation is a matter of great concern. Because the temperature and the condition of the atmosphere in storage areas such as library stacks are important in mediating the rate of degradation of the stored records, these parameters are controlled. However, atmospheric pollutants such as particulate matter, various oxides of nitrogen, sulfur dioxide (SO2), and ozone cause degradation of records (Baer and Banks 1985). In some cases the removal of air pollutants from the external air by the air conditioning system is inefficient (Hughes and Myers 1983).
In the stacks, many records are often stored in containers and not exposed directly to the stacks environment. These records experience a microenvironment that may be different from the macroenvironment of the stacks. If this microenvironment in fact is, or could be made to be, less aggressive, then expensive changes in the air conditioning system might be obviated.
Recently, Passaglia (1987) studied this microenvironment with specific reference to storage in the National Archives and Records Administration (NARA). He suggested that a study of the protection mechanism provided by the container, in particular the cardboard boxes used to safeguard a large quantity of archival material, would be valuable. Passaglia presented models and calculations to estimate the effectiveness of various containers for protection of archival materials from environmental pollutants. However to utilize these models, values of the diffusion constant through boxboard are needed.
In this article we report the diffusion constant of SO2 through various boxboard materials commonly used to fabricate storage boxes. The concentration range of SO2 used in these experiments was 10–150 ppm of SO2 in air. Using these measurements along with Passaglia's model, we are able to estimate the effectiveness of the archival boxes in providing a microenvironment that is different from the macroenvironment of the stacks.