The smell of an old book, the study asserts, is caused by hundreds of volatile organic compounds that the paper releases into the air over time; those compounds also reveal changes in the paper’s condition. Strlic’s test was applied to “sniff” 72 historical papers from the 19th and 20th centuries; the documents contain rosin, pine tar and wood fiber, which are the materials that degrade quickest in old books. Binding and other media, including photographs, also contribute to the pace of a book’s degradation.
