This part of IEC 61577 describes the specific requirements for instruments measuring the volumetric activity of airborne short-lived radon decay products and/or their ambient potential alpha-energy concentration outdoors, in dwellings, and in workplaces including underground mines. This standard applies practically to all types of electronic instruments that are based on grab sampling, continuous sampling technique and electronic integrating measurement methods. The measurement of activity retained by a sampling device, for example a filtering device, can be performed both during sampling or after the completion of a collection cycle. The different types of instrumentation used for measurements are stated in IEC 61577-1.