By Jeffrey Levin
For every problem, there exists at least a theoretical solution. There is, for example, the often cited story of a scientist at a major think tank whose solution for stabilizing the earth's climate was to adjust the tilt of the planet. When asked how he would accomplish that, the scientist responded that it was his job to offer solutions, not to implement them.
Twenty-five years ago, the museum community was offered a theoretical solution to its own environmental dilemma. Duncan Cameron, writing in Museum News, (46)9:17-22, 1968 presented a prescription for the ideal museum environment. In order to ensure the perfect preservation of a collection, a museum would have to include the following: a site on high land, a fire-proof and vibration-free structure protected against shock and sound waves, elaborate emergency back-up control systems, a constant temperature in the range of 60-68° F, constant relative humidity in the range of 50-60%, pollution-free air, total darkness, an absence of all organisms (including humans), and cooperation of the Almighty. To museum conservators, the achievement of Mr. Cameron's quixotic suggestion may seem as remote a possibility as altering the axis of the earth.
In 1984 the Getty Conservation Institute embarked on a wide-ranging research program directed at problems in the museum environment. Motivated by a desire to expand the body of environmental knowledge, the program developed projects that could, in an integrated way, fill gaps in existing information.
The scope of the GCI's environmental research includes the penetration of outdoor pollutants into the museum, indoor-generated pollutants, microenvironments, pest control, and museum climatology. This research reflects the Institute's emphasis on preventive conservation and care of collections, an emphasis shared by growing numbers of conservators, both in the United States and abroad.
What, in fact, has been the result of the Institute's environmental research? Conversations with a number of professionals for this article produced no single answer. Some research findings are being readily applied. Others have yet to be fully disseminated. While the importance of the research was cited by many, obstacles to utilizing the findings and remaining gaps in knowledge were also alluded to.
In light of these exchanges, Conservation thought it appropriate to review some of the GCI's environmental research and its impact. While the approach here is informal rather than comprehensive, it is hoped that it will provide a perspective on what has proven useful and what more needs to be done.
The Getty Conservation Institute's environmental research began with a three-year study, conducted with the California Institute of Technology (Caltech), on photochemical oxidants. Particular attention was paid to ozone and nitrogen dioxide. Subsequent studies examined the penetration of other pollutants into the museum environment, as well as pollutants produced within the museum itself. The research encompassed surveys of museum pollution concentrations, quantification of effects on materials, development of passive monitors, and the formulation of control strategies.
The Institute's research in conjunction with Caltech assessed the migration of pollutant gases and particles into museums in Southern California. It established that ozone and nitrogen dioxide, both components of photochemical smog, could seriously damage paintings and other works of art by causing pigments and dyes to fade. Also studied was soot deposition which damages objects by discoloration, and which, in the case of some textiles, can be nearly impossible to remedy. An aspect of both areas of the research was identifying strategies that could be used to mitigate these problems.
Research in this area is continuing on two historic monuments at opposite ends of the globe: the Buddhist shrines in the Yungang Grottoes near Datong, China (a GCI Special Project), and the chapels and statuary of the Wieliczka Salt Mines, a World Heritage site near Cracow, Poland.
A second Polish project is under consideration investigating pollution and particle infiltration into Cracow's Wawel Castle and National Museums, which house historic collections of art dating from past centuries when the city served as Poland's royal capital. The objective is to assess the threat of soiling of the collections due to the presence of too much particulate matter in the outdoor air. Central Cracow, itself a World Heritage site, is subject to high levels of sulfur dioxide, sulfur related pollutants, and particles.
The Cracow museum project, sponsored by the U.S. National Park Service (NPS), the Polish Academy of Sciences, and the Conservator General of Poland, is largely based on the GCI-Caltech research. "The technology, methods, and fundamental principles for both this project and the salt mine project were developed under the Getty's environmental research program," says Susan Sherwood, a Physical Scientist with the Preservation Assistance Division of the NPS. The project is slated for formal approval in May, and is expected to begin by summer.
Dr. Glen Cass, a Professor of Environmental Engineering at Caltech, was a principal investigator on several of the GCI-Caltech studies and is involved in the Chinese and Polish projects. Since the original studies were published, Dr. Cass has been solicited by a number of people to examine related problems elsewhere. "The methods we developed and tested in Los Angeles have broad applicability to diagnosing the nature of and solution to, problems occurring all over the world," he notes. "The number of locations where you have serious outdoor air pollution problems in the immediate vicinity of museums, historical buildings, or archaeological sites is very large. Major population centers in Eastern Europe and Asia tend to have air pollution levels capable of producing significant damage. And the time schedules for remedying these pollution problems are generally longer than the length of time before noticeable damage to collections is going to occur. There is a need to provide a faster response to protecting cultural properties."
Mitigating pollution problems is not always a large-scale enterprise. El Pueblo de Los Angeles Historic Monument, a block of historic structures in downtown Los Angeles, was part of the survey of museums and historic buildings performed during the original research. The survey's testing demonstrated the effectiveness of Plexiglas barriers used to seal in a furnished, historic room in El Pueblo's Sepulveda House. The Plexiglas eliminated 90% of visible particulates, diminishing as well the penetration of several outdoor pollutants.
John Coghlan, for ten years Artifact Curator at El Pueblo, is convinced that installing Plexiglas in other historic rooms within the park would not only help preserve objects, but permit continued viewing by the public while over time reducing costs. "It's an expensive initial approach," says Mr. Coghlan, "but it's well worth it. It cuts the maintenance way, way down. In the long-run it's very cost-effective."
The Inside Danger
Increasing numbers of conservators are concerned over the threat posed by indoor-generated gaseous pollutants. As recognized for a number of years, pollutants emitted by wood products and other materials used in storing or displaying objects can extensively damage collections. Silver objects can tarnish, while articles of lead or leaded bronze can suffer considerable corrosion. As the result of pollutants, calcareous materials, such as shells, develop a white or gray crystalline efflorescence called Byne's Disease.
Some of the Getty Conservation Institute's environmental research has been directed toward detecting and mitigating these pollutants. This research included a survey of airborne carbonyl pollutants at 17 U.S. institutions from New York to Honolulu. Nearly 600 air samples were collected from almost 200 sites within these institutions. The survey provided important baseline data on formaldehyde, acetaldehyde, formic acid, and acetic acid.
The survey was part of the research's five point strategy for pollutant control which included: developing an analytical method for detecting specific pollutants found in museum environments; conducting a survey to determine the baseline levels of pollutants; determining at what level pollutants cause detectable damage; identifying or developing economical passive monitors; and developing mitigation methods and technologies.
With regard to passive monitors, one pollutant, formaldehyde, received particular attention. In a project conducted with the firm of Daniel Grosjean and Associates, the Institute identified and tested an inexpensive passive monitor capable of measuring low levels of formaldehyde in museum air. William Lull, a museum building and renovation consultant with the New Jersey firm of Garrison/Lull, considers the passive monitors tested by the Institute to be a valuable contribution to his own work. "I've got three or four clients using them now to check new construction as well as existing exhibit case conditions. It's something we can use on a regular basis to reliably test this in the field."
In the mid-1980s, Pam Hatchfield at the Boston Museum of Fine Arts coauthored with Jane Carpenter an important study of the dangers posed to the collections by formaldehyde. Ms. Hatchfield regards the passive monitors identified by the Institute as the sort of research needed research that results in simple, inexpensive solutions. "The experimentation and testing which leads to the development of these technologies may cost a lot of money," she says, "but now relatively inexpensive passive monitors for atmospheric pollutants are available to just about any institution or private individual. It's a tremendous benefit to us."
On the other side of the Atlantic, May Cassar says that use of the passive monitors has been limited by two factors. First, getting museum staff to read an intimidating-looking scientific report, such as the one describing the monitors, is not easy. Even then, says Ms. Cassar, "They will turn round and say, 'Well, we haven't got that sort of money.' Then it's a case of saying 'The research is spending the money, but the final result doesn't necessarily cost you that much to implement.'" The second problem is availability. At present there is no distributor for the passive monitors in the United Kingdom, and they must be ordered from the United States.
Interest in the formaldehyde passive monitors has fueled the desire for similar monitors to detect other gaseous pollutants. More than one expert pointed out that additional research to identify or develop such monitors would have immediate and broad applicability. The GCI is, in fact, in the process of identifying passive sampling devices for other pollutants found in the museum environment. Monitors will be tested for acetic acid, ozone, nitrogen oxides, and sulfur dioxide.
The work on indoor-generated pollutants by the Getty Conservation Institute and others has helped alert conservators and curators to the extent of the danger to collections lurking in materials used in exhibit cases. Complementing this new knowledge is the Institute's research into the use of active and passive sorbent strategies for controlling pollution in cases. This research found that activated carbon and a sorbent based on potassium permanganate (both of which are widely available) are highly effective sorbents for a number of pollutants.
At the Bishop Museum, in the state museum of Hawaii, this research is being applied to historic display cases first installed in 1899 when the museum's Hawaiian Hall was dedicated. Testing by both a GCI team and passive monitoring revealed that the cases, constructed of koa wood and containing ethnographic and historic materials from Hawaii's monarchy period, were emitting destructive pollutants. In response, the museum staff created a prototype using one of the cases. Leaving the exterior unchanged, the case was retrofitted by sealing the koa wood from the interior and substituting stable materials for existing plywood pedestals.
The case was tested after eight weeks, and no indication of gases was found. A false floor for the case was constructed, and underneath it was placed silica gel to moderate humidity and activated carbon as a passive scavenger for interior pollutants. Nearly a year after the case was resealed with monitors, there is no indication of pollutants and humidity levels remain stable.
Dale Kronkright, a former Bishop museum conservator who now frequently consults for the museum, is pleased with the work on the prototype. "What it means is that with available materials, using low technology and totally passive methods, it appears that we can create a stable environment with very low, unmeasurable levels of indoor gaseous pollutants, even in a very large case. What's really critical about the work the GCI's been doing is that they've developed a protocol for measuring two of the most important organic gases that are present in commonly used exhibit materials, formic and acetic acid, and their aldehydes," observes Mr. Kronkright. But, he cautions, there are a lot of other pollutants yet to be assessed. "We've just scratched the surface in terms of knowing what we are putting these collections in."
Analysis of display case materials is also part of the Arizona State Museum's upcoming ethnographic exhibit on the indigenous peoples of the Southwest. The permanent exhibit, consisting of over 600 artifacts, is being installed in a 70-year-old building where climate control fails to meet conservation standards. According to Nancy Odegaard, a conservator with the museum, "we felt that microclimate casing was the only reasonable way to go." The exhibition's planning grant from the National Endowment for the Humanities included funding for a visit to the GCI to consult on case design issues. Subsequently, museum staff performed the most vigorous testing of display cases ever undertaken by the museum.
An unusual microenvironment study was conducted by the Getty Conservation Institute in 1988-89 for the Egyptian Antiquities Organization. The objective was to design and construct a prototype storage display case for the Royal Mummies collection in Cairo's Egyptian Museum. Researchers found that a hermetically sealed case containing nitrogen and only minuscule amounts of oxygen effectively retarded microbiological activity and had potential to eradicate insect life within the case. This finding had important implications for another area of the GCI's environmental research pest control.
There are approximately two dozen urban insect pestsa variety of beetles, moths, and cockroachesthat can damage objects. With a taste for cellulose, wool, silk, or leather, these pests pose a continual threat to objects composed of such organic materials.
Presently, museums rely primarily on commercial fumigants to control pests. The drawbacks to these fumigants vary, including the time they require to be effective, their hazardousness to people, their negative effect on objects, and the harm they cause to the environment. Now, as more regulatory attention is drawn to toxic substances, even the availability of some fumigants is becoming an issue.
"In Europe, things are fast disappearing," reports Alan Postlethwaite, Deputy Director of the Smithsonian Institution's Conservation Analytical Laboratory. "Vikane has never really been authorized. Methyl bromide is forbidden in Holland, for instance, and ethylene oxide is forbidden almost everywhere. Like here, the criteria for its use are highly restricted."
Encouraged by research for the Royal Mummies cases, the GCI joined with Dr. Michael Rust of the University of California at Riverside, to further investigate the effectiveness of nitrogen atmospheres for pest eradication. The study found that exposure to a nitrogen atmosphere containing less than 0.1% oxygen, conditioned to museum relative humidity levels, caused 100% mortality in a few days for a number of the pests which commonly plague museums and collections.
At Houston's Museum of Fine Arts, Decorative Arts Conservator Steve Pine has used nitrogen fumigation since September 1992 to control several varieties of beetles attacking textiles and furniture in the museum's collection. "I don't know of a museum that isn't struggling with this issue," he says. "All the other available means of fumigation have proved problematic." The advantages of nitrogen are, he says, that it can be managed in-house without the services of a licensed fumigator, that it is comparable in cost, and that it will not interact with objects. "Nitrogen is a major breakthrough for museums."
For over a year, John Burke, Head Conservator of the Oakland Museum, has been fumigating the museum's ethnographic collection with carbon dioxide, another new technique being tried at a few places in the United States. Because the effectiveness of carbon dioxide and its interaction with collections materials remain open questions, he is interested in making more use of nitrogen. For the last two years, he has performed some fumigation by placing objects in vapor barrier bags and adding nitrogen in conjunction with Ageless?, an oxygen absorber. But he has yet to achieve high enough concentrations of nitrogen in the museum's fumigation bubble to make the use of nitrogen there feasible.
Despite this difficulty, Mr. Burke is encouraged by the safety and effectiveness of nitrogen. "Insect pests are a problem we're always going to face," he says. "To be able to control these critters in a way that is both effective and nontoxic both to the object and, more importantly, to the staff and the public is truly revolutionary. I think nitrogen fumigation promises a way that not only works, but can be done without harming the materials and without danger to the people doing the process."
If nitrogen use by museums becomes widespread, legal issues may arise. Nitrogen as a gas is not officially designated as a fumigant. Should it become so, its use would require a licensed, registered fumigator, and all the accompanying paperwork. For now, however, nitrogen fumigation done in-house on an institution's own objects confronts no legal obstacle.
Without controls on temperature and relative humidity, museum objects can be subject to stress caused by physical expansion and contraction. The damage can range from loosening of furniture joints and warpage of wooden panel paintings, to the tightening and loosening of canvases that increase stress on paint films.
The basis for the Getty Conservation Institute's research in museum climatology was the need for reconciling energy conservation with what the conservation field has deemed proper temperature, humidity, and air quality standards. The objective of the studies was to provide guidance to engineers designing museum heating, ventilation, and air conditioning (HVAC) systems, in order to help them meet the specific needs of a museum's collection, including a stable environment, while controlling HVAC costs through energy conservation.
J. Carlos Haiad, an engineer and a principal in the engineering firm of Ayres & Ezer Associates which participated in the studies, says the research has generated interest in the United States, Canada, and the United Kingdom. Mr. Haiad said his firm tries to provide systems that can keep energy costs affordable while maintaining high air quality standards. "In fact, he says, the firm's design proposals often include the use of activated carbon air filtration systems rather than the more expensive chemical filtration systems, a recommendation that has occasionally brought them into conflict with HVAC manufacturers.
Murray Frost, a private consultant based in British Columbia, finds the Institute's studies in energy conservation and climate control of real use to his clients. While institutions that utilize his services have already committed to environmental controls and standards, the studies help his clients make informed decisions, and provide support for his recommendations.
Mr. Frost, who spent ten years working at the Canadian Conservation Institute, now helps museums incorporate preventive conservation concepts in planning renovations. "There's been a preventive conservation consciousness for a longer period of time [in Canada]," says Mr. Frost, noting that the government has provided museum funding in this area since 1979. However, he continues, "There haven't been publications to hold up and say, 'Here's the proof.' It's helpful to have those references now."
Disseminating The Research
One issue raised by several professionals is dissemination. Though the GCI's research has significant implications for the work of many conservators, because of the form in which findings are released (i.e., scientific reports), the information may not reach fully into the conservation community.
Of equal concern is the dissemination of findings to other members of the museum community, including curators and administrators, whose decisions affect the care of collections.
"In reality, there are only a small number of institutions that have changed behavior, and they've only done it because of key individuals who were there," says Dale Kronkright who, in addition to his consulting, serves as chair of the AIC's Objects Specialty Group. Education, he insists, is the big problem. "Conservators need to take the professional responsibility for educating people who can use this information."
Another issue raised was applicability. Some, like Lisa Mibach, a private conservator based in Oberlin, Ohio, think that the application of research should be more incorporated into the research itself. "The topics being looked at [by the Getty] are certainly cutting edge topics, where there's a real need to know," says Ms. Mibach, previously the Director of the Intermuseum Laboratory in Oberlin. "But I think it would help to be a little more populist in the design of the research so that you can come out with applied information as opposed to pure research information."
Pam Hatchfield, who chaired the AIC's Objects Specialty Group prior to Dale Kronkright, sees the process of research as assembling the pieces of a large puzzle. "Conservators sometimes feel that in order to answer a question scientists must focus on such a small part of the problem that it takes years before the information becomes useful to the practicing conservator," she notes. "We're now reaching a critical mass of information about environmental concerns. We have a meaningful body of knowledge from which we can begin to draw practical solutions to problems."
Dr. Norbert Baer, Hagop Kevorkian Professor of Conservation at New York University, believes that the inroads made by the Institute's work will become increasingly apparent. Still, he says, it is too much to expect that research alone will lead directly to action. Typically, a "triggering event" or the need to solve a particular problem prompts a review of research. "It's unlikely that people are going to be galvanized into action by a laboratory study. On the other hand, if there is an event and that event has consequences, then they will look for back-up." At that point, the years of studies have impact. "It is in building a body of work," says Dr. Baer, "that the real contribution lies."
Solving the environmental problems of museums is a matter of great interest to conservators and to the wider museum community. Many institutions and individual researchers have devoted considerable attention to this critical subject, and in the process advanced our understanding of the museum environment. The Getty Conservation Institute acknowledges a debt to all of them.
Conservation would like to know more about the views of its readers on environmental research and the ideas presented in the accompanying article. We invite your written comments.
For scientific information pertaining to specific studies conducted by the Getty Conservation Institute, please contact James R. Druzik, Conservation Scientist in the GCI's Scientific Program.