The Austrian Radon Project (ARP)

Dasösterreichische Radonprojekt (ÖNRAP - in Deutsch)
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A new multimedia information program (in german)can be used to get Informationon Radon.
The actual version of this program can be downloaded (compressed,ca.35 MB). 


1. Introduction

Radon is a naturally occurring radioactive noble gas. It is usuallythe main contribution to the radioactive dose to which men are exposedto. Radon is a decay product (via several steps) of uranium. The main sourcefor indoor radon is the ground from where it penetrates into the houses.Other possible sources are building material, water supply (see Radonin Water) and natural gas. Increased lung cancer rates could be observedby several groups of miners working in high radon concentrations. Extrapolatingthese data to usual indoor radon concentrations means a 5 to 15% contributionof radon (radon progeny) to the observed lung cancer rate.

The Austrian Radiation Protection Commission has introduced a referencelevel of 400 Bq/m3 for existing buildings and a value of 200Bq/m3 for new houses as annual means which should not be exceededin indoor air.

The Austrian Ministry of Health and Consumer Protection initiated theAustrian Radon Project (ARP) to investigate the distribution of the indoorradon concentration in Austria. The project is organized by the Faculty of Physics, Nuclear Physics Group, University of Vienna (co-ordinator:H. Friedmann) with the participation of the AtomicInstitute of the Austrian Universities, the ARC Seibersdorf research (Seibersdorf,Department of Health), the Austrian Agency for Health and Food Safety (AGES),the Institutefor Material Physics, Technical University of Graz, Working Group: Radiation Physics, the DivisionMaterial Research and Physics, University of Salzburg, and the local authorities.The Federal Ministry for Health and Women and the Federal Ministry of Agriculture, Forestry, Environment and Water Management funded the project at itsfinal stage.

In 1991 the concept for the project was developed and existing radon-relevantdata reviewed. The final concept was first tested in a pilot-project inthe Mühlviertel region and in Linz (Upper Austria) in 1992/93. In1993/94 the pilot-project was extended to whole Upper Austria. In 2001the project was finished. Although data are now available for all partsof Austria (in totally nearly 40 000 measurements were performed) the informationon indoor radon will always stay incomplete until the last home is investigated.Therefore any new measurement will improve our knowledge on the radon riskin Austria.

2. Implementation

Approximately one in 200 homes was statistically chosen for the investigation(rural areas - in towns the density of investigation was lower). Generallythis means a more detailed investigation in areas with a higher populationdensity. However in cities the usually applied measurement density seemsto give not substantially new information compared to a much smaller numberof measurements. Therefore in cities the measurement density was drasticallydecreased. Measurements were done generally in the sleeping room and inthe living room. Track-etch detectors (system Karlsruhe) and electret detectors(E-Perm) were used for 3 months' measurements; charcoal detectors withLSC measurements (Picorad) were used for 3 days' measurements. (For furtherinformation see the references.)

The time-tabel of the investigations during the Austrian Radon Projectwas as follows:

1992/94 Upper Austria

1994/95: Lower Austria

1996: Styria

1997: Salzburg and Carinthia

1998: Tyrol and Vorarlberg

1999: Vienna and Burgenland

2000 - 2002: Additional measurements in all parts of Austria

All measured radon data can be converted to a radon potential whichwas introduced to compare radon data measured under different conditions.This radon potential is defined (essentially) as the annual mean radonconcentration in a commonly used living- or sleeping-room at the groundfloor in a house without basement.

3. Results

The radon concentration in a home depends strongly on building parametersand on living conditions. Therefore, ALL DATAGIVEN HERE ARE ONLY MEAN VALUES FOR CERTAIN AREAS AND CANNOT BE USED TOPREDICT RADON CONCENTRATIONS IN ANY SINGLE HOME. For furtherinformation see the references  and the Radon-InformationProgram (in german).
  Annual mean in Austria:
Counties                    Municipalities

Radon Information Program (compressed, ca. 35 MB)


Radon distribution functionfor:



Lower Austria

Upper Austria







4. Radon in Water

Since the beginning of the 20th century radon in water has been measured.The aim for such measurements was mainly the search for springs for medicinaluse. Later systematic investigations on the radon concentrations of springswere done in several areas, however, only a few years ago the systematicinvestigations were extended to the whole country.

Generally radon in water is a minor problem in radiation protection.In most cases radon is removed during water treatment in waterworks andin addition the short half-life of radon (3.8 days) reduces the radon concentrationon the way from the water source to the consumer's tap. Also cooking removesradon from the water and most of the radon incorporated by drinking wateris rapidly exhaled. Nevertheless there are some cases where radon in watercan cause problems. Mostly it is radon escaping from water into the airwhich can lead to high radiation doses to the lung of the exposed persons.Even a low radon concentration in water can produce a high radon concentrationin air in buildings with a high water passage (e.g. waterworks). But alsotap water from private wells with substantially enhanced radon concentrationposes a problem, especially when taking a shower.

The knowledge of such possible risks triggered the investigation onthe probability of high radon concentrations in spring and ground water.In addition to the measured data geological information must be used toextrapolate the probability predictions to areas without measurements.

A scaling into 3 classes was  introduced (Radonin Water Map):


Researchat the Nuclear Physics Group
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Dasösterreichische Radonprojekt (ÖNRAP - in German)
Researchat the Nuclear Physics Group
Faculty of Physics, Nuclear Physics Group, University of Vienna, Home Page

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