Molecular Contaminants
The primary contaminants of concern are sulfur dioxide, nitrogen dioxide and ozone. These contaminants are known to chemically attack artifacts, causing permanent, irreversible damage. The type of damage and severity depends upon the amount of contamination and the artifacts’ materials of construction. There may be other molecular contaminants present that are specific to individual applications and/or geographic locations that are not currently thought to be detrimental in LAMs. For example, in new construction, there could be levels of formaldehyde that would require additional controls.

Particulate Contaminants
There are two major concerns with particulate contaminants: non-viable and viable particles. Non-viable particles cause soiling of the artifact. Cleaning of many artifacts is not an option, as it can often result in damage. Viable particles, usually in the form of airborne fungal spores, bacteria, and molds can also deteriorate artifacts, especially if temperature and humidity are not maintained at proper levels.