Legal regulations on the utilization of raws and materials assigned for construction are applied inPoland taking into account radiation protection. A qualification coefficient f2 = SRa, where SRa is the 226Ra concentration in the material expressed in Bq/kg, connected with the limitation of radium concentration in the product due to the emanation of 222Rn (in parallel with qualification coefficient f1 limiting whole-body exposure for gamma radiation) is used for the purpose of limitation of the 222Rn concentration in buildings assigned for permanent residence of people.
Epidemiological evidence of lung cancer risk from radon is based mainly on studies of menemployed underground in mines where exposures are relatively high in comparison to indoorexposure. Nevertheless direct evidence of risk from residential radon is desirable. In 1990, a studywas started comprising 12 000 inhabitants of an area with elevated radon concentrations. The meanlevel in the houses was higher than general mean of the country by factor of five. In the period1961-95, a total of 173 lung cancers were observed.
The Austrian Radon Project (ARP) is aimed to investigate and measure systematically the indoorradon concentration in about 0.5% of all Austrian homes. With the information from this surveyareas of enhanced indoor radon concentration can be identified and people living in such areasshould be encouraged to mitigate their homes. The radon potential is introduced by normalizingthe observed radon data to a standard situation. By mapping the radon potential an overview on thegeological risk for enhanced indoor radon concentrations will be available.
The very high indoor radon concentrations found in the western part of Switzerland in the early80th were at the origin of an extended research programme between 1987 and 1991. The resultsobtained showed a real need for a further detailed radon programme. This should be based on thestate of knowledge, take economical aspects into account and be practically orientated. The mainaim is to deal with elevated concentrations.
For over ten years STUK (The Radiation and Nuclear Safety Authority, Finland) has performedsystematic indoor radon mapping with municipal health authorities. In the most radon-proneprovinces (Uusimaa, Kymi and Hme) there are about 480,000 low-rise dwellings. It is expectedthat in 51,000 homes the action level of 400 Bq/m3 is exceeded, of which about 6,000 have beendetected. In the rest of Finland the numbers are: 820,000 low-rise dwellings, 17,000 expectedcases of exceeding the limit, of which 800 were detected, respectively.
The relation between an increased risk for lung cancer and exposure to indoor radon is assessed inepidemiological studies. Both the quality and reliability of smoking data and the radon exposuredata are of primary importance. Contemporary measurement of radon concentration in thedwellings of the individuals in a case-control study is traditionally used to assess the past radonhistory. These assessments contain large uncertainties since the contemporary measured radonconcentration might not be representative for the situation a long time ago.
A data set of long-term radon measurements in about 2200 houses in southern Belgium has been collectedin an on-going national Rn survey. The spatial variation of indoor Rn concentrations is modelled byvariograms. A radon distribution map is produced using the lognormal kriging technique. A GIS is usedto digitise, process and integrate a variety of data, including geological maps, Rn concentrationsassociated with house locations and an administrative map etc. It also allows to evaluate the relationshipsbetween various spatial data sets with the goal of producing radon risk maps.
It is estimated that more than 5000 householders in the UK have taken steps to reduce high radonlevels in their homes. In 1993 a number of homes with successful remedies installed were asked toparticipate in a study to determine the long term reliability of those systems. This involved the annualremeasurement of the radon concentration in each dwelling.
A soil gas measurement method developed earlier [1] was applied to boreholes drilled to belowfoundation depth. Radon concentration and permeability were measured at 50 cm intervals. Inradon prone areas permeability showed to increase with depth over several orders of magnitude,indicating a low permeability top layer with a thickness of 0.5 m and more. A radon availabilityindex (RAI) was empirically defined and the maximum RAI of each boring proved to be a reliableindicator for radon problems in nearby houses.
First, models (room models) published in the international literature allowing the exposure togamma radiation indoors due to building materials to be assessed are reviewed and discussed. Forone of them, a sensitivity analysis regarding the effect of changing the parameters (e.g. dimensionsof the room, thickness and density of the walls, etc.) used in calculations is performed.
Login