Results of a preliminary survey on radon in Belgium.

Results of a preliminary national survey on radon in houses in Belgium are presented. The indoor radon concentration was determined in 1983 in 79 houses with passive integrating detectors. In 77 of the examined cases the radon concentration is less than 250 Bq/m3. The highest reported value is 330 Bq/m3. The frequency distribution is found to be log-normal with a geometric mean of 41 Bq/m3 and a geometric standard deviation of 1.7. The influence of some human and environmental parameters is also studied. Because of the limited scale of the pilot study only a tendency can be derived.