Abstract: A radon measuring device having a housing formed of at least two mating portions and coupled together by a fastener. At least one aperture extends through the housing to permit ambient atmosphere to enter the housing and includes a filter or membrane positioned to cover the aperture for filtering radon from other particles from the ambient atmosphere as it enters the housing. A radon detector is positioned within the housing for measuring the concentration of radon in the ambient atmosphere which passes through the aperture and the filter into the housing. A filter support member also is inclined for positioning the filter proximate the aperture and pressing the filter against the housing.

Abstract: A radon measuring device having a housing formed by at least two mating portions. The housing includes a plurality of apertures along at least one of its surfaces to permit entry of ambient atmosphere into said housing, a membrane or filter positioned proximate an interior surface of the housing covering the apertures for filtering the ambient atmosphere which enters the housing, and a radon detector within the housing positioned in a plane substantially normal to the surface of the housing containing the apertures. The housing can also include a filter holder within its interior for positioning both the filter and the detector in their respective positions as well as alignment tracks for alignment of the filter holder with respect to the housing.