Obviously not everyone can have closed cases, with their own microclimates. If the design, then, admits (or even encourages, as with fans) interchange of air with the surrounding environment, I would suggest not only incorporating "molecular sieve" material into the interior installation, but also placement of a material such as Purafil's P-800 medium, in thin section, over the locations of ingress - vent holes, gaps in casework, etc. While this material is described as "utilizing the chemisorbent technology of potassium permanganate-impregnated activated alumina," and is not represented or rated for particulate entrapment, its structure suggests that it will also have such a function. IMHO Henry Grunder Conservation/Preservation Coordinator The Library of Virginia