Question

what are the internal and external causes of deterioration of library materials?

Answer 1

Deterioration of library materials caused by natural elements, such as temperature and humidity
extremes, light, air-born pollutants, mold and pests, is usually gradual and cumulative, and is always
irreversible. Some library materials deteriorate more quickly than others because they are made from
materials that are inherently unstable, such as acidic paper. Natural disasters, such as floods or fires,
and building problems, such as leaking roofs or dysfunctional HVAC systems, may cause more
immediate deterioration.
The materials of which library and archive collections are composed, namely paper, parchment, palm
leaves, birch bark, leather and adhesives used in bookbinding, are susceptible to two main forms of
deterioration. One is biological deterioration caused by insect attack and/or fungal growth, and the
other form of deterioration is caused by adverse environmental conditions such as extremes of
dampness or wide fluctuations in relative humidity associated with large variations in day and night
temperatures, light and atmospheric pollutants. These two forms of deterioration are interconnected
because humid conditions favor the growth of fungi and accumulations of dust and dirt will attract
insects