In the recent decades, the conservation field has become increasingly aware of the threat of microclimates to the deterioration of objects. There have been numerous reports of damage to objects while on display or in storage. Consequently, strides have been made in the detection, mitigation and understanding of damage from indoor-generated pollutants. However, not all intervention results in a better situation. The author's mantra is: "Test, test and re-test."
It is known that only "safe" materials should be used in proximity to objects. Not everyone has access to testing facilities. Some institutions will share test results. However, one must use caution with lists as not all batches are the same and not all vendors produce identical materials. Test, test and re-test.
While one risk may be eliminated; it cannot be assumed that there is no risk. Consider pressed-wood boards that have been linked to high emissions of formaldehyde. The industry changed the manufacturing process to produce formaldehyde-free MDF boards. This did not affect the emission of organic acids from the woods themselves. Zero-formaldehyde boards still have organic carbonyl pollutants, acetic acid and formic acid. Test, test and re-test.
Another palliative measure is to line offensive boards with a barrier foils to isolate the gases from the objects. Air quality testing has shown that barrier foils can significantly reduce concentrations if properly applied, but they do not eliminate the problem. Test, test and re-test. The use of adsorbents and absorbents has been used to reduce gases in microclimates. How much should be used, and how long do they last? The GCI will start a research project on sorbents in July 2000.
Should suspect pressed-wood cabinets be replaced with new cabinets, not necessarily? Museum air quality monitoring has shown that new microclimates can have higher concentrations of organic carbonyl pollutants than the "bad" cases that they replaced. Most 30-year old plywood cases will have low levels of formaldehyde and even acetic acid. If it is replaced with a cabinet constructed with inferior materials the problem may be repeated. There have been situations in which museum-grade cabinets were improperly manufactured, resulting in high levels of pollutants inside. It is important to determine if the new materials will be better or worse for the objects.
Questions and Issues remain the same... More research is needed.
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© May 11th, 2000