English

Reports a series of experiments made in the U.S. Bureau of Mines radon test chamber to study the effects of condensation nuclei, humidity and turbulence on the rapid deposition or plateout of radon daughter activity on the chamber walls. Under low humidity conditions the presence of a small fan reduced the working level by 41%. The activity was not deposited on the walls by the turbulent flow from the fan but actually became attached to the fan blades. High relative humidity (>80%) totally inhibited this observed effect.

Reviews methods for the measurement of the activity concentrations of radon-222 daughters in air. Describes method which enables activity concentrations as low as 0.05 pc i/l of ra a to be measured with simple readily transportable equipment. The method presented here also measures RaB (214 Pb) and RaC (214Bi) activity concentrations and working levels with improved precision compared with established methods.

Presents method for estimating the heat requirements of buildings. The method is based on the ASHRAE degree day method with modifications to take into account a) solar radiation incident on a building surface, b) variation of solar energy gained through windows, c) variation of air infiltration withwind speed and inside-outside temperature difference and d) heat generated by inside activity, such as lights, people etc.< Gives sample calculation for a house and compares with calculation by ASHRAE method.

Reports air leakage measurements made in a mobile home using sulphur hexafluoride as a tracer gas. The home was located in an environmental chamber where it was possible to measure and control the temperature outside the home. The effect on infiltration rate of inside-outside temperature difference, simulated wind, installation of storm windows, opening of doors and operation of the furnace for was investigated. Also reports pressurization measurements which showed that the installation of storm windows had little effect on air leakage.

Presents model of indoor pollution that assumes a linear relation between indoor pollutant levels and the air change rate. Discusses effect of heating system and cooking on pollutant levels and ventilation rate. The model predicts that when air change rate is reduced 4-fold, heating systems pollutant contributions can still rise up to 3-fold despite the saving in energy from reducing ventilation. Suggests precautions are necessary when tightening building envelope. Recommends that pilot lights be eliminated and effective kitchen ventilation systems installed.

Gives general discussion of sources of radon gas and its daughter products. Reviews measurements made of radon concentrations in air. Outlines control strategies for limiting radon in buildings.

Heating systems may emit pollutants into living spaces of buildings. Presents model for estimating exposure to pollutants allowing for variation of air change rate and inside-outside temperature differences. Examines the effect of energy conservation measures. Concludes that if ventilation alone is reduced the pollutant concentrations will rise but if reduced ventilation is balanced by increased insulation then pollutant contributions will remain unchanged. The analysis applies only to pollutants generated by the heating system.

Reports measurements of concentrations of thorium, potassium, uranium radium, and relative radioactivity of building materials used in the United Kingdom. Gives table of results. Examines in particular calcined gypsum prepared as a by product in the manufacture of superphosphate fertilizers. Discusses the relationship between radium concentration and gamma-ray dose rate

Reports results of measurements of the environmental radiation inside Norwegian houses. Three types of measuring equipment were used: a scintillation rate meter specially designed for low intensity measurement, a geiger counter with a rate meter, and an ionisation chamber. The average doserate in air due to environmental radiation was found to be 87 mrad/year insidehouses with outer walls of wood. 115 mrad/year for buildings with outer walls of concrete and 129 mrad/year for buildings with outer walls of brick.

Points out that conservation measures such as storm windows which seal a building protect occupants from outdoor air pollution but amplify effects of pollution generated indoors. Considers which effect is greater. Develops a model relating indoor air pollutant concentrations to outdoor concentrations and to v, the air exchange rate, which is consistent with reported behaviour of common pollutants. Model predicts that indoor concentrations follow outdoor concentrations but maxima and minima lag behind, and are not as pronounced as theiroutdoor counterparts.