radon

The Harvard School of Public Health and the Energy and Environmental Policy Centre of the Kennedy School of Government, under the auspices of the Electric Power Research Institute and the Gas Research Institute, conducted a"Workshop on Evalu

Eleven countries are cooperating to establish guidelines for minimum ventilation rates which are sufficiently large to meet the demand for outdoor air in buildings without unnecessarily wasting energy. The most important pollutants have been identified as: carbon dioxide, tobacco smoke, formaldehyde, radon, moisture, body odour, organic vapours and gases, combustion products and particulates. To a certain degree some of thesesubstances can be used as indicators for acceptable air quality to establish minimum ventilation rates.

The relation between air infiltration rate and indoor concentrations of radon gas, radon daughters, and formaldehyde has been investigated for both summer and winter conditions in a number of Toronto houses with low rates of natural ventilation.

Describes the work of the Department of Climate and Building Services of the National Swedish Institute for Building Research. Full scale trials, field measurement and measurement technology and methods applied to indoor climate are described. Research on airtight buildings, radon, air quality and efficient ventilation, occupant requirements and effects on human performance is also summarised. Dummies are used to measure heat transport to or from parts of the body, and for measurement of humidity.

Describes expectations people have of indoor climate. Notes that the quality of indoor climate has often taken second place to fashionable architectural and material considerations. Refers to concern for improved environment and awareness of formaldehyde, radon and other pollutants and the need for correct ventilation to achieve derived air quality. Provides guidelines for air quality, and the thermal environment in both housing and working premises.

Radon concentrations were measured in about 1000 Dutch dwellings and at 200 outside locations using passive monitors. A median concentration of 24 Bq/m3 was found for the dwellings with a highest value of 190 Bq/m3. Seasonal effects were found to be small. Correlations were observed between median radon concentrations and construction parameters including ventilation rate. The concentrations outside show an unexpected dependence on the location. Comparison with previous grab-sampling data on radon-daughter concentrations reveals an average equilibrium factor of 0.3.

Three different investigations of radon in Swedish dwellings are presented - a nationwide study conducted primarily to determine the collective dose to the Swedish population from exposure to radon and radon daughter, a supplementary study of newly built detached houses in order to find out whether theregulations in the Building Code prescribes acceptable radon levels in new houses built on normal ground, and measurements made by the local authorities in order to find houses with levels of radon daughters above the norm.

To develop effective monitoring and control programs for indoor radon it is important to understand the causes of the broad range of concentrations that have been observed. Measurements of indoor radon concentration and air-exchange rate in dwellings in several countries indicate that this variability arises largely from differences among structures in the rate of radon entry.

The problem of radon emission in buildings first came to light at the end of the 1970s, when a report by the Swedish National Institute of Radiation Protection revealed high radon daughter concentrations in some houses. Temporary limits on permitted concentrations in different types of dwellings were imposed in Sweden. They were related to the age of dwellings, due to the known historical use of alum shale in lightweight concrete.

Notes that the Department of the Environment is considering the implications of imposing limits for the maximum annual dose of radiation to which occupants of existing and new homes should be exposed, as recommended by the Royal Commission on Environmental Pollution in its report of 1984. Describes radon's properties and origins in buildings, where levels are at least ten times higher than outdoors. The occupants of some homes, chiefly on granitic soils, receive up to 100 times the national average dose from radon. Explains the units used when discussing radon.