Books emit gases, including acids, when they decompose

Books emit a complex mixture of organic compounds, including volatile acids, when they start to decompose.

Researchers in the university library will test the same gases to see which of its millions of volumes are at risk.

The aim is to improve the way the books are stored and develop a system to alert librarians when decaying books begin to produce destructive acids.

By sampling the air in different parts of the library, researchers hope to identify areas with a high acid content.

Air tested

The books can then be treated before further decay sets in.

The theory is that even a modern text will degrade faster if it is stored in an area with older, "smellier" books.

During the first stage of the project, researchers are comparing copies of the same texts in different libraries, to see how the various ways they have been stored might have affected their condition.

Then, samples of the air in different parts of the libraries will be tested to measure the quantity of acid that is being produced.

The results of the study are due to be published in 2009.

Ways of reducing acid in storage, including specific filters in the air conditioning which could remove organic materials in the atmosphere, may be considered.

This could also prove controversial for those who prefer the smell of the old library.