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Massachusetts Board of Library Commissioners Resource Guide Collection

Preservation in Massachusetts Libraries: Environmental Monitoring

Subscribe and connect with Massachusetts Board of Library Commissioners (MBLC) Preservation Specialist Jessica Branco Colati and colleagues around the Commonwealth that work to advance the protection of cultural collections.


Note: We're renovating the Preservation in Massachusetts Libraries guide during Summer 2024. Please bear with us as we add, update, and reorganize MBLC's preservation resources.

2021-2024: FREE Environmental Monitoring Hardware, Software, & Training

The goal of the program is to provide individual libraries in the Commonwealth of Massachusetts tools and support to improve local environmental monitoring programs. Participating libraries were/are must complete a LibWizard application (now closed). Program running from FY2022 - FY2024


UPDATE, 10/2023:

Under consideration for FY2025 and beyond.

Background on Environmental Monitoring

Some objects and some certain formats can be particularly vulnerable to rapid chemical changes, like films and magnetic media. Maintaining optimal (cold) storage environrments for them can be very important for their preservation. But for most library, archive, and museum objects, some of which have survived well over long periods of time without environmental controls, chemical decay from the climate is not their biggest threat.

Practically, for most libraries in the Commonwealth, there two reasons to monitor your collection environments.

  • To minimize the chance of potentially catastrophic risks associated with sustained high RH: that is, mold, condensation, and pests.
    • Mold spores are literally everywhere, in every cubic foot of air inside or out, literally all the time. They don’t do damage to collections unless they get a chance to bloom and grow, which requires a storage environment that is humid, dark, and enclosed with stagnant air. A good rule of thumb: if RH is sustained above 70% for three days, improve the environmental conditions (dehumidify or move air), before the mold can take root and eat your collections.
    • Condensation can occur when nice, warm, 45%RH air comes in contact with a freezing cold surface. Weeping walls, windows, skylights can be big problems in otherwise climate controlled air in a storage space that is enclosed with an external wall with windows? Watch out for weeping walls or windows in the wintertime. Watch out for flat files or other cabinets adjacent to cold air pockets.
    • Insects tend to thrive in warm humid environments.
  • To create a more stable (less risky) environment for your collections for the long term by optimizing existing systems or building data in support of building changes or improvements.
    • Have collections been exposed to extremely high relative humidities in spring, summer, and fall? Gather data to build a persuasive case to support moving or renovating collections spaces.
    • If you and your collections stakeholders have specified target set points for temperature and humidity in storage or display areas, it can be helpful to monitor the system to optimize its activity and catch malfunctions when they arise. Sometimes collection areas are zoned together with non-collections spaces; sometimes the system sensor may be within the limits of the set point but the climate in the collection areas are outside of your preferred ranges; and eventually machinery and equipment break.

With this background, MBLC proposes a new approach to Environmental Monitoring with the following three goals:

  1. To educate and empower librarians with more knowledge about best practices in environmental monitoring.
  2. To provide easy-to-use tools for collections stewards to better monitor any sustained periods of high humidity in enclosed areas.
    1. Basically to mitigate risky conditions favorable for mold, condensation, and insect activity as quickly as possible. For this aspect of the program, I am not so interested in pure data collection or big-picture reporting, but rather in letting real-time data drive immediate risk-mitigation actions. (The natural next step of an MBLC environmental monitoring program would be to provide support for mitigating those improper conditions, but for now, we’ll leave it just identification.) I’m considering how best to satisfy this goal and what the program might look like, and so I’m learning more about tools that can help real-time identification of environmental problems. What tools or strategies would fit best here, for libraries that likely don’t have much capacity to run a highly sophisticated monitoring program or complicated software on their own? For example, I think there are some very interesting dataloggers on the market that feed real-time data to smart phones apps -- but I worry about their accuracy, durability, and connectivity requirements, and there are a lot of options to choose from. I want to provide the tools for motivated collection managers to watch over their own data but without it being too complicated – I don’t think the right fit is to outsource the real-time monitoring to MBLC or consultants.
  3. Help to identify systemic issues in your storage environment by collecting data over an extended period of time, at least one year.
    1. Create a report that can be shared with administration, stakeholders, and the wider community. Usually it’s to support arguments to renovate or build new storage spaces, or move collections. This aspect of the program would be focused on identifying and describing specific problems in storage environments and would be similar ins some ways to the previous MBLC environmental monitoring program. It would be for a longer period of time, however, and applicants would be screened to make sure it’s a good fit and they’re committed. I think this aspect of the program should be performed by a preservation or conservation professional, whether it’s me or a consultant.
    2. Provide periodic imports and analysis of climate data from HVAC systems. Consultants cperform the work.


There is a great deal of literature on environmental monitoring. In gathering this update, I specifically reference:

Reilly, J. (2018, September.) Specifying Storage Environments in Libraries and Archives. Conference Paper: Gray Areas to Green Areas: Developing Sustainable Practices in Preservation Environments, 2007. The University of Texas at Austin.  Retrieved from

Image Permanence Institute. (2012, July.) IPI’s Guide to Sustainable Preservation Practices for Managing Storage Environments. Image Permanence Institute, Rochester Institute of Technology. Available for Purchase here.

(Michalski, S. (2018, May 17.) Agent of Deterioration: Incorrect Temperature. Canadian Conservation Institute. Retrieved from