London Metropolitan Archives

Historic objects made of cellulose acetate are potential sources of indoor pollution in heritage collections. As these objects degrade, volatile organic compounds, including acetic acid, are produced and emitted. High concentrations of acetic acid can increase the degradation rate of both organic and inorganic objects stored nearby. In this study, micro-invasive sampling and ion chromatography were used to quantify acetic acid emission rates from objects made of cellulose acetate, including 3D objects and photographic negatives. It was observed that some degrading objects emit acetic acid at high rates, even under standard environmental conditions (20 °C and 30% RH) that are prescribed for storage of objects made of cellulose acetate. The emission rate was found to be governed by the internal diffusion for thicker cellulose acetate objects and by the surface evaporation for thinner objects. In the diffusion-controlled mode of emission, the airflow did not accelerate acetic acid emissions. To compare the storage options for cellulose acetate objects, the emission rates of acetic acid were used as the inputs for models predicting the equilibrium acetic acid concentrations in various enclosures (archival box, surface-coated archival box, metal can, and display case). It was observed that surface-coated boxes contained higher concentrations of acetic acid than other enclosures, mainly due to their low air exchange rates and deposition velocities.

This volume contains selected essays in celebration of the scholarship of the medieval historian Professor James L. Bolton. The essays address a number of different questions in medieval economic and social history, as the volume looks at the activities of merchants, their trade, legal interactions and identities, and on the importance of money and credit in the rural and urban economies. Other essays look more widely at patterns of immigration to London, trade and royal policy, and the role that merchants played in the Hundred Years War.

This paper will show that by positioning itself as a centre of excellence for emergency planning and disaster recovery, London Metropolitan Archives (LMA) has established itself as a key player for the City of London. LMA could demonstrate it already had detailed emergency plans and disaster recovery plans in place which meant it was ahead of other parts of the organisation. The archive reference room resembled very closely a disaster recovery centre. Discussions enabled the vision of a disaster recovery centre to be located in the archive building at LMA. The paper will look at the ways in which this has provided challenges in space planning and technological infrastructure but its reputation as a provider of excellent public services has enabled it to be a very valuable participant in wider security and emergency planning initiatives.