The object of this study is to measure radon concentrations, both in the soil and buildings of the JRCIspra, in order to compile a radon map indicating areas with low, medium and high concentrations.The monitoring is being performed following the recommendations for the implementation of TitleVII of the European Basic Safety Standards Directive (BSS) concerning significant increase inexposure due to natural radiation sources. For measuring radon both passive and active methods arebeing used. The passive method is a passive track detector in Karlsruhe beakers.
Coals mined in some regions of the Transdanubian Middle Mountains in Hungary have elevatedconcentrations of 226Ra. The slags and ashes derived from these coals have been used as buildingmaterial for schools and kindergartens. As the 226Ra reached up in these waste products of coal-firingsystems, the gamma dose contribution in the buildings, which contained them, was calculated.
A large-scale radon survey has been carried out from 1995 to 1998 in southern Greece, in order toestimate the radon concentration in Greek dwellings and the exposure of the Greek population toradon. The design was administratively orientated. The statistical criterion for the selection ofsampling locations and the distribution of radon dosimeters was the percentage of dwellings of eachlevel of the administratively classifications in respect to the above level. This way of distributionassured that all the inhabited geographical regions were covered.
Indoor radon concentrations were determined with the use of track-etched detectors and two monitors,both for radon and one for the decay products, in various regions of Greece. Until now, 1137 dwellings have been measured. Some factors, that influence the radon concentration in dwellings, are discussed in this paper. The factors, used in this analysis, were derived from the householders answers to the relevant questions about various physical features of the dwelling. Different statistical methods were used, as the unpaired t-test and the ANOVA method.
To clarify the mechanism of radon transport from soil to surface, long term continuous measurementsof radon exhalation were conducted at one site in combination with measurements of radon concentration in soil gas, soil temperature, pressure difference, soil moisture and meteorological parameters. Based on the results of measurements over a two year period, the influence of meteorological and soil parameters on the exhalation was estimated.
Basic considerations1. Legal base fixing the limiting value for radon in residential and recreational premises.(Radiological Protection Ordinance of 22 June 1994)2. Engagement in a campaign measuring the radon concentrations, finding the areas with radon prone buildings, and mapping those areas.3. Collaboration with the homeowners living at a high radon concentration to define a project how to reduce it.
Radon surveys started in Estonia in 1989. The Department Building Physics at the Estonian BuildingResearch Institute measured radon levels in dwellings, in building materials produced in the country,and in the soil. The indoor radon concentrations in more than 400 houses were measured under grabsamplingtechniques using Lucas cells. The highest measured radon level was 6700 Bqm-3. The resultsof these measurements made during 1989-91 showed that the main source of indoor radon is the soilunderneath buildings.
In Denmark, a new survey of indoor radon-222 has been carried out. One-year alpha trackmeasurements (CR-39) have been done in 3019 single-family houses. There is from 3 to 23 housemeasurements in each of the 275 municipalities. Within each municipality, houses have been selectedrandomly. One important outcome of the survey is the prediction of the fraction of houses in eachmunicipality with an annual average radon concentration above 200 Bqm-3.
Numerical modelling is a powerful tool for studies of soil gas and radon-222 entry into houses. It isthe purpose of this paper to review some main techniques and results. In the past, modelling hasfocused on Darcy flow of soil gas (driven by indoor-outdoor pressure differences) and combineddiffusive and advective transport of radon. Models of different complexity have been used. Thesimpler ones are finite-difference models with one or two spatial dimensions. The more complexmodels allow for full 3D and time dependency.
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