Pollutant-artifact degradation

Once the types and sources of pollution have been identified, it is necessary to explore possible pollutant-artifact degradation scenarios. The fundamental chemistry of wood, presented earlier in the chapter, provides the interactive backdrop. In reality, archaeological wood will be subjected to a host of atmospheric pollutants and varying climatic conditions at one time. However, to understand the entire complex system, it is important to study the interaction of its individual parts. 

Pollution. Gaseous and particulate air pollution is a fact of life. Although it may be invisible to the human eye, its detrimental effects on a fragile wooden object may be very visible. Aided by an uncontrolled warm, humid microclimate in the display case, pollution chemically degrades wood and can diminish the aesthetics of an artifact by discoloration or decay. 

Herein lies the paradox. As a cultural representative, wooden artifacts provide the visitor and the scholar with insight into past cultures. However, public display of delicate artifacts can cause further degradation. This delicate balance between visitor needs and conservation considerations must be attended to by the museum staff. A stable environment (control of temperature, light, pests, and atmospheric pollution) must be provided for such artifacts, while still remaining true to the educational function of a museum. 

The performance of polymer artifacts is adversely affected if degradation occurs during the various stages of polymer manufacture, fabrication, and subsequent exposure to the environment. Molecular oxygen is the major cause of polymer degradation and is responsible for the ultimate mechanical failure of polymer artifacts. The deleterious effect of molecular oxygen is accelerated by many other factors sunlight heat ozone atmospheric pollutants water mechanical stress adventitious metal and metal ion contaminants. 

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