Pollution is not only harmful to us, it’s also damaging to museum objects, with pollutants having been identified as one of the ten primary threats to museum collections.
Pollutants present within the museum can either be particulates, like dust, or gases such as sulphur dioxide, nitrogen oxide and ozone. Standard everyday materials such as wood, plastics and paints can also emit compounds harmful to museum objects. In order to avoid introducing a pollutant source ourselves, we take special care to select the materials we use in our collection storage and display areas.
However, there is another source of pollutants we encounter in museums: the objects themselves. The Science Museum Group collection has a vast array of fascinating complex objects. Unfortunately, many of these objects are made from a combination of materials which, despite looking beautiful, are not the best suited to be in proximity with one another.
Examples of these challenging combinations include elegant 18th century medical kits and scientific instruments, such as the syringe set above, that are stored in fabric lined wooden boxes. These kits usually contain metallic elements, which are likely to corrode due to sulphur gases. These gases are emitted by fabrics such as wool, a common choice for lining in these cases.
The fabric itself is vulnerable to acids, including those which can be emitted from certain types of acidic woods like oak, a commonly used material for storage boxes. Moreover, wood’s acidic emissions can also cause corrosion on the metallic elements.
Plastics and rubber are other examples of materials that emit pollutants which can harm other elements within the objects. Good examples of these are objects from our prosthetics collection. Volatile organic compounds (VOCs) emitted from degrading rubber can accelerate the deterioration of leather or metal elements in the object.
In the Conservation and Collections Care team, one of our tasks is to mitigate the pollutants affecting our collection as much as possible, even when the objects themselves are the source.
Maintaining suitable environmental conditions is key. High relative humidity can make some materials more susceptible to absorb pollutants, whilst high temperature can accelerate chemical reactions and exacerbate the damage they cause. It is also important to limit the amount of external air that comes into areas with collections and the use of air filtration units in stores with large amounts of objects that produce harmful emissions.
This is just some of the work we do behind the scenes to ensure that we can continue to inspire our visitors with the objects in our collection. You will be able to see some of these remarkable objects in our new Medicine Galleries opening in 2019.