radon

Discusses the physical, chemical and biological effects that moisture can have on indoor air pollutants such as formaldehyde, radon, aerosol particles, minerals from concrete, ozone, nitrogen dioxide, polyurethane, microbes and organic vapours.

Discusses building 'safe' houses, describes the decay chain of uranium 238 and the qualities of radon, and risks of developing lung cancer run by miners and householders. Figures for lung cancer in the USA are quoted. Details from three studies in Houston, Maine and Sweden are given. Discusses sources of radon, e.g. water, building materials, soil. A study of houses in Pennsylvania indicated that high radon concentrations occurred over Cambro-ordovician sediment rock. Discusses movement of radon from soil into dwellings.

Introductory talk on the indoor air quality problem. Compares risk of radon pollution in houses to the risks of smoking tobacco, and gives a definition of levels of concern. Mentions filtering of indoor air by means of an air-to-air heat exchanger, the interaction between ventilation and sources, e.g. unvented combustion heaters and carbon dioxide emissions; measurements of nitrogen dioxide are compared, and formaldehyde concentrations in 28 different commercial buildings.

Uses a model to estimate the incremental risk of lung cancer associated with increased radon concentrations in indoor air resulting from decreased air infiltration caused by increased air tightness of dwellings. Gives results for selected changes in the air exchange rate. Discusses findings.

Recent work by the National Radiological Protection Board indicates that higher than average levels of exposure due to radon occur in the South West. West Devon District Council has undertaken its own survey on radon concentrations to see whether these can be associated with lung cancer incidence. The control of radon gas is likely to have implications for building structure and ventilation. There is a potential conflict between the desirability of increasing ventilation to cut radon levels on the one hand and reducing air infiltration to save energy on the other.

Subjects covered include: problems of radon, formaldehyde build-up in the home, residential indoor air quality, effect of moisture on other pollutants, epidemiology of indoor air problems, setting standards for recognising harmful concentrations in homes, the effect of retrofit conversion measures, thepublic's perspective.

Discusses the natural ventilation of the Paintings Room of Altamira Cave, in Spain. The radon-222 concentration was measured by scintillation cells of capacity 500 cm3. From the mean monthly Radon-222 concentration the natural ventilation was calculated using Wilkening's method. Compares the variations in ventilation rate (monthly) with the temperature differences between the Paintings Room and the Hall Chamber. Natural ventilation is the major factor affecting changes in the carbon dioxide concentration.

Indoor radon concentrations are approximately lognormally distributed, with the range of concentrations varying from a one in one thousand risk of contracting lung cancer to high one per cent risk. Source strength rather than ventilation rate seems to be the major factor causing the broad distribution in concentrations. There is general agreement that the most important mechanism for radon entry into homes is not diffusion but pressure driven flow of soil gas that carries radon from the soil into the homes.

Contains further papers, reports and conference summaries from the 3rd International Conference on Indoor Air Quality and Climate, 1984, as well as afull list of authors and titles of papers printed in this and the previous volumes.

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.