Project Objectives
Biodeterioration of collections is a major concern for cultural institutions in hot and humid regions where favorable conditions for insects, fungi, and bacteria are found. The threat posed by biological and microbiological attack in tropical regions often supersedes the potential for chemical aging or mechanical damage.

A common method for preventing microbial damage is to lower temperature and humidity through the use of air conditioning systems. Difficulties arise, however, when applying air conditioning to historic buildings as the superstructure and interiors cannot always withstand the installation and operation of these systems. As well as being intrusive on the building fabric, air conditioning systems are also expensive to properly install, operate, and maintain and may not guarantee the desired interior environment. As a result, alternative solutions to this issue were urgently needed.

This project focused on the development of economical and sustainable strategies that significantly reduced biodeterioration by improving the physical environment of collections housed in historic buildings in hot and humid regions. Specifically, it researched alternatives to conventional air conditioning systems by studying the control of relative humidity through ventilation and heating, while allowing larger variations of temperature. The project's primary objectives were:

• to define and test strategies that arrest microbial activity through the environmental control of cultural institutions housed in historic buildings in hot and humid climates using locally sustainable technologies;
• to install, operate, and evaluate several climate control systems consisting of ventilators and heaters that are humidistat-controlled;
• to disseminate information generated by this project through publications and workshops.

Project Summary
In 1997, the GCI initiated a project to investigate strategies to preserve collections in hot and humid climates. The project hosted an experts meeting in 1998 on the conservation of collections in tropical and subtropical regions. From discussions at the meeting, it became evident that three topics merited further study: 1) assessment methodologies for threats to collections and the buildings housing them; 2) the control of pollutants, light, and lighting; and 3) economical and sustainable climate improvement strategies (i.e., effective alternatives to air conditioning systems), primarily for controlling biodeterioration.

In each of these areas, the GCI conducted work.

During the latter part of the 1990s, the Institute developed a set of guidelines for evaluating the environment of museum collections and their buildings. In collaboration with the Federal University of Minas Gerais, the Federal University of Bahia, and the Vitae Foundation (São Paulo) of Brazil, the GCI successfully used these guidelines to assess the environment of the Museum of Sacred Arts in Salvador, Brazil. Results of this work were presented at the 1998 annual meeting of the Associação Brasileira de Conservadores e Restauradores de Bens Culturais (ABRACOR) held in Salvador, Brazil. These guidelines were used in GCI's Latin American Consortium project.

This project also produced a comprehensive report on the effect of light on materials in collections in hot and humid climates. The GCI's research on Pollutants in the Museum Environments continued under the Performance of Pollutant Adsorbents project. The objective of this project was to increase the protection of objects placed in display cases or other microenvironments from threats posed by indoor-generated gaseous pollutants. This research was separated from the Collections in Hot and Humid Environments project in June 1998 as part of a GCI reorganization of its work.

The third topic of concern from the 1998 experts meeting was the development of economical and sustainable climate improvement strategies. The GCI undertook several studies related to this subject. The first effort evaluated the application of sustainable climate control strategies to historic houses at the Shelbourne Museum in Vermont. A second study focused on the control of microbial activity in museums, archives, and libraries using ventilation systems. Details of these studies are described in the project components section. Further research on the issue of climate improvement has continued under the current Alternative Climate Controls project.