This research project will study the relationship between room-level relative humidity, object-level water activity, and the associated risk of fungal germination on organic collections. This research will inform the management of collection environments, by balancing the preservation of organic objects with environmental sustainability, and increasing resilience in the face of collection emergencies. This will be a comparative study focusing on two major classes of materials susceptible to germination, namely paper and parchment, and will assess their germination response to changes in relative humidity, equilibrium moisture content, and water activity. During this project, IPI will work in collaboration with Georgia Southern University (GSU) and the Colonial Williamsburg Foundation (CWF). GSU will undertake a discrete portion of research to determine how the rate of germination on organic substrates is impacted by different environmental conditions, while CWF will deploy dosimeter samples across representative historic sites to help understand how the water activity of organic materials on open display is influenced by changing environmental conditions in situ.