Bie ; bML geek ae aR au. etek my rae bei tar re atte provers Saeoesiumentstae, Ceeea ceaeessaber sEncEh eenasSSaeae eee Betas omurihs Saba wT Fame:saat ste)a oa ENVIRONMENTAL RADON CONCENTRATIONS AN INTERIM REPO = UNYo-~4¥6l ee ‘by Harold Glauberman and A.J. Breslin Health and Safety Laboratory New York Operations Office U.S. Atomic Energy Commission The Health and Safety Laboratory is investigating the variability in space and time of natural radon concentration as a portion of its contribution to the United Nations scientific endeavor. This is an interim report of that work. Measurements were begun in late November 1956 and will continue indefinitely. One hundred and twenty samples have been collected and analyzed to date. Most of the sampling has been done in and around New York City; a few samples have been collected in New Jersey. The present phase of the investigation is primarily a pilot study. Attention is being directed to instrumentation, sampling technique and semple variability, and the development of a systematic sampling program. Although the collected samples have yielded valuable data, they are more important as a basis for designing an integrated pattern of collection. PROCEDURE | a The basic measurement is one of instantaneous radon concentration. A grab-sample is collected in a one-liter glass flask ey analyzed in the laboratory by a pulse counting fonization technique. \1 ) The results are reported in curies/liter of elemental radon in air. capacity is limited to six flasks per day. The analytical Whenever practicable, sam- ples have been replicated so that the sampling error could be computed. ' When replicates have been obtained, individual successive samples have been collected as rapidly as possible at a fixed location. Measurements are also being made of the daughter products of radon. At each sampling location, the daughters are sampled for ten minutes by drawing air at ten liters per minute through a one-inch diameter molecular filter disc. Alpha activity is measured in the laboratory with a scintillation counter. Initially, we attempted to measure the daughter decay as a function of time according to the method described by Tsivoglou, Ayer, and Holaday. (2) However, the counting statistics : proved to be too unreliable at the activity levels measured. Nevertheless, a means is being sought whereby the daughter activity can be used to define the state of radioactive equilibrium of the decay products ‘with radon. “Oy POS