Abstract Passive radon monitoring devices based on damage track detectors are very attractive for the assessment of long-term radon exposures. These devices can be divided into two broad categories, formed respectively by diffusion and permeation samplers. A permeation-type device based on a heat-sealed polyethylene bag is used in Italy. For short-term (one week or less) radon measurements, damage track detectors are not considered to be sufficiently sensitive. This paper illustrates how simple it is to measure short-term radon exposures in dwellings by spark-counting large detector areas of cellulose nitrate foils.