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Environmental Monitoring

PEM2 Datalogger
Image by Image Permanence Institute

The UW Libraries uses the Image Permanence Institute's dataloggers and software to monitor the environmental conditions of selected library collection areas.  Our goal is to document, monitor, and optimize collection storage environments to benefit the long-term preservation of the UW Libraries' collections.

All library materials are subject to biological, chemical, and mechanical deterioration but research has shown that a stable moderate climate increases the life and usefulness of collections. For example, a book stored at 75°F and 55%RH is estimated to deteriorate twice as fast as a book stored at 68°F and 45%RH. Environmental Guidelines for the Storage of Paper Records (NISO-TR01-1995) recommends 70°F maximum and 30-50%RH (with a maximum daily fluctuation of +/- 2°F and +/- 3%RH) for combined stack and user areas. Optimum conditions for preservation are colder and drier (35°-65° 30-50%RH). Some inherently very unstable materials like photographs and film greatly benefit from cold storage.

In general, stable cooler and drier conditions slow the aging of materials and reduce the risk of insect and mold problems. Of course, light, dirt, dust and pollutants also play a role in deterioration.