Environment

Environmental factors that affect the deterioration of library materials include temperature, humidity, light, and pollution. High temperatures increase deterioration rates by speeding up the molecular processes that cause paper in books to weaken and become brittle. High humidity increases reactions of acids in paper, also causing brittleness. On the other hand, extremely low humidity can cause stress in velum books and cause cracking. Florescent light can cause fading of paper and book covers and can cause staining when it reacts with lignin, a chemical in paper. Pollution contains acids which can cause paper to deteriorate and become embrittled.

Maintaining the proper environment is essential for preserving library collections. At the University of Maryland, we monitor the environment by collecting data on hygrothermographs and PEMs (Preservation Environment Monitor) and analyzing the data with computer software. We try to maintain a stable environment where the temperature and humidity fluctuate minimally.

What you can do
You can help maintain the environment by keeping windows closed and keeping shades pulled. We have florescent light-blocking film installed on some windows and on many light fixtures. If you notice that the air conditioner has stopped running or that your area feels damp, it is very important that you report the problem to your supervisor and Facilities and work with Preservation staff to ensure that collections are not harmed.