The sulfur dioxide in the air combines with the water in paper to create sulfuric acid. Oxidizing substances combine with ozone to form nitrogen oxides, peroxides and more ozone. Dust and other particulate matter acts as a corrosive because of the acid droplets that form around the nuclei of dirt. Even when dry, dirt is an effective abrasive as well as providing an incubator for mold. For the last several years Olin has been plagued by high humidity which has supported fantastic annual mold growths.
Mold consumes the starch sizing in book cloth and paper and the collagen in leather.
Insects Cockroaches visit the library for a drink of water, and then they stay to eat the animal glue used in the spines of books and the pizza fragments left by readers. Silverfish and firebrats, their heat resistant cousins, eat the starch sizing on the surface of paper and bookcloth. Bookworms exist everywhere. In New England the common form of bookworms are carpet beetles and their larvae. Dogs looking for bones use books as substitutes.