Abstract: A method for establishing and maintaining a microbiologically clean environment in a room by painting at least its wall and ceiling surfaces with a porous layer formed of a porous material, such as perlite, zeolite or micronized silicon dioxide, optionally mixed with a fungicide or bactericide, then repeatedly spreading an aqueous liquid mixture containing a sanitizer over the porous layer, the water in the aqueous liquid mixture being evaporated between each application, leaving sanitizer in the pores of the porous layer.

Abstract: A passive filter for taking up gaseous substances, preferably gaseous smelling substances, from a space, including a porous sorbating, self regenerating material composition, including two material components (A, B), of which a first material component (A) consists of one or more porous materials such as perlite, zeolite, bentonite, silicon dioxide ground to powder or christobalite, and a second material component (B) consists of one or more materials with the capability to take up water molecules directly from the surrounding air, such as silicon dioxide gel, starch or derivatives of cellulose, gypsom, silicates of alkali, aluminum silicate, or fuller's earth. The material components (A, B) are kept joined into a lattice by means of a binder, at which the first material component (A) join with 50-95%, preferably 80-90% (percentage of weight), and the second material component (B) with 5-50%, preferably 10-20% (percentage of weight), in the material composition.