radiation

Radon in indoor air is discussed in the perspective of the effective dose equivalents from other sources of radiation. Estimates of equivalents from indoor radon and its contribution to lung cancer incidence are reviewed. Swedish experiences with cost effective remedial actions in a cost-benefit perspective.

Gives an account of the results of research into ventilation and radiation in buildings, including one-family dwellings and blocks of flats. Investigation includes recording the air change rate, the radon levels, the radium emanation rate and gamma radiation. The object of the investigation is to obtain background material for continued research into limit values for radon and radium emanation levels in dwellings.

Summarises measurements of natural outdoor environmental radiation made in the Eastern United States, in New England and in Western Europe. Also reports measurements made in single family and multiple-family dwellings in the metropolitan New York area. The general conclusion from the indoor measurements is that the radiation level inside houses in that area is generally somewhat lower than, but not very different from, the outdoor levelat the same location.

Tests carried out during the sixties and seventies showed that there was a correlation between lung cancer and the existence of radon gas in mines and that there was radon gas in homes built of aerated concrete based on slate. This led to political activity with regulations for limits on emanation in new, re-built and existing buildings. Provisions were also made for grants to help house owners finance the improvements specified.< In the new bye-laws, SBN 80, gamma radiation is not to exceed 50 mu.R/h, the radon content is not to exceed an annual mean of 70 Bq/cu.m.

By-product gypsum, produced as a waste in the phosphate industry, could be used in bulk as a building material but it has a higher radium content than other building material. Reports an analysis of the dose rate that would result if gypsum were used for a two-storey, three-bedroom, centre terrace house. Discusses the dose from beta radiation, gamma radiation and radon gas,assuming one air change per hour.

Reports a nationwide investigation of gamma radiation in Swedish houses, made by the National Institute of Radiation Protection in Stockholm. The occupants of 2000 apartments and houses were picked at random and asked to participate in the investigation. The measurements were made with thermoluminescent dosimeters CaSO4 - Dy in teflon. Three detectors were sent to each of the selected dwellings by post. Finds that the accuracy of the detectors is about+ or - 25%.

Reports investigation of the radon concentrations in Swedish homes. The concentrations of radon and daughter products, air change rate and gamma levels have been investigated in 63 dwellings in seven types of houses built at the beginning of the 1970's in the town of Gavle. Gives table of results. From these results the absorbed dose in the basal cells of bronchial epitheiuim in the lung has been calculated for various periods.

Reports study of the exposure rate due to the gamma-ray natural background in some representative areas of Italy using a portable high-pressure ionization chamber. In some areas spectrometric measurements were made to distinguish between contributions to the total from cosmic rays and from natural radioactive series. The measurement areas were chosen to be representative of the main geological formations.