radon

A methodology was developed to calculate health damages due to exposure to radon emitted to indoor air for use in dwelling life cycle assessment. Fate factors were calculated based on dose conversion factors and effective outgoing airflows. Effect factors were calculated from linear relationship between dose and cancer cases. Damage factors are expressed in terms of disability adjusted life years (DALYs).

Performance of radon mitigation systems, including active sub-slab ventilation, basement over-pressurization and crawlspace isolation and ventilation, was monitored in 12 houses in the USA during 10 years. Results are given showing the radon concentrations measured quarterly or annually. Results of the inspection of the mitigation systems and the needed maintenance and modifications of the systems to maintain and improve their performance are also reported.

Considering the likelihood of contributions of various indoor air pollutants to detrimental health effects, the Community-COST Concertation Committee of the Concerted Action "Indoor Air Quality and its lmpact on Man" (COST Project 61 3) decided that indoor radon is a well studied indoor pollutant both in terms of occurring concentrations and expected adverse health effects. In July 1985 the Article 31 Euratom Treaty Group of Experts set up a Working Party to study and report on this matter.

Radon concentration in outdoor air and in buildings is very variable, showing diurnal and seasonalvariations. Long term measurements with track etch detectors lasting up to one year give the mostprecise one year averages. It arrives, however, that we are obliged to get results much sooner e.g. forscreening measurements. How long should we measure radon concentration to get proper results? Wehave studied the problem of selecting proper time interval on the basis of our six long-termmeasurements in Krakw using AlphaGUARD PQ-2000 ionization chamber.

Rad Elec Inc., located in Frederick, MD, USA is the only commercial producer of electret ionchambers (EIC) systems. These are distributed under the brand name of E-PERM, electret-passiveenvironmental radon monitors. Different versions of these are used in various applications, whichinclude: measurement of indoor/outdoor radon, thoron (220Radon), radon flux, radon in water, radiumin soil/building materials, environmental gamma radiation, tritium in air and on surfaces, alphacontamination on surfaces and in soil.

The application of a radon model is useful to understand the processes that drive the radon gasbehaviour from its sources to its accumulation indoors. Since in a given inhabited house the detailedknowledge of the values of all the parameters that affect indoor radon levels is not available, theresponse of the model has to be explored in a reference site in which all the parameters are supposedto be known. We call this site the reference configuration.

Radon goes through four stages from its formation until it reaches a living environment: i) itsgeneration in the source medium, ii) its migration in the source medium, iii) its entry into a dwelling,and iv) its accumulation indoors. Many parameters of different origin take part at each stage, and mostof them are time-dependent. In this paper we discuss the requirements that an ideal model, whichconstitutes a Global Dynamic Radon Model (GDRM), should fulfil to predict indoor radon levels inliving areas of inhabited houses.

The study aims at measuring the gamma activity concentration (226Ra, 232Th and 40K) of sub-slabfilling gravel of Finnish houses. This study forms a part of a wider study aiming at exploring factorsaffecting high indoor radon concentrations in Finnish dwellings. The gamma activity and radonemanation were measured from gravel samples sent from 229 Finnish municipalities, the gammaactivity was reported. Gamma activity was determined by HPGe gamma spectrometry. The averageradium and thorium concentrations of the filling gravel were 23 and 27 Bq/kg, respectively.

The council directive 96/29 EURATOM laying down the Basic Safety Standards for the protection ofthe health of workers and the general public against ionising radiation might force some Europeanwater supply companies to take technical measures for lowering the indoor air radon contents in theirwaterworks. A suitable method for this, is the installation of water aeration equipment to remove radondirectly from raw water and lead it out off the building.

From the end of 1996 through March 1999, the spatial and the temporal variability of the soil 222Rnconcentration was investigated at a 20m x 20m test field with porous soil in 0.5 m and 1.0 m depth atnine positions each and at 1m x 1m plots at four positions each. For this, soil gas was collected weeklyinto evacuated scintillation cells and was analysed subsequently for radon activity. In the 20m x 20mfield the spatial variability is characterised by coefficients of variation (C.V.) of 26% at 0.5m, and13% at 1.0 m depth. Within the 1m x 1m plots the C.V. Were 4% and 2%, i.e.