Radon in a self-selected sample of Israeli homes, schools, and workplaces

Some 1,100 residences and places of work and 400 schoolrooms in Israel were tested for ambient air radon activity concentration in response to requests by the owners, tenants, or local authorities. A polyethylene vial containing activated charcoal was exposed to room air in each of these structures for 7 days, sealed, and transported to the laboratory. Adsorbed radon was extracted with a toluene-based cocktail which was then subjected to liquid scintillation counting. Mean radon activity concentrations were found to vary from city to city by more than an order of magnitude, indicating strong regional differences. The countrywide geometric mean was found to be 38 Bq/m³; the median, 37. The range for these means was 6-77 Bq/m³; the medians, 11-100 Bq/m³. The highet reading was 9,100 Bq/m³. Our results are basically in line with those from the United States and much of Europe, but apparently higher than those found in the United Kingdom and Japan. It may be fairly said that mass testing for radon (²²²Rn) inside buildings in the United States began in the wake of the finding of a radon activity concentration in excess of 100,000 Bq/m³ in the home of the Watras family in Boyertown, PA in December 1984 (1). To date, literally millions of American buildings have been tested, and mandatory testing of schoolrooms has begun in some states. In Israel, by contrast, where such a dramatically high measurement has not (yet) occurred, only 5 structures had been checked for radon by 1989 (2). Since then, several thousand premises including private homes and ground-floor apartments, schools, and places of work have been tested. Several Israeli cities, notably Tel Aviv and Ramat HaSharon, have begun testing all ground-floor and basement schoolrooms. Interim findings are presented here concerning some 1,500 of these tests, done in 90 communities, all of which were performed in response to requests by the owners, tenants, or local authorities. This self-selected sample, though it includes structures throughout most of the country, is not necessarily representative of the country as a whole.