Measurement campaigns

Main conclusions of studies 1991-2017

Risk factors

Studies conducted by the Radiation Protection Division (Division de la radioprotection - DRP) have identified the risk factors associated with the accumulation of radon in housing:

• absence of concrete slabs
• no cellar
• no mechanical ventilation
• geographic location
• old buildings
• presence of a chimney or stove without a fresh air supply
• leaky connections and pipe runs

Houses with high radon levels may present a combination of several of these risk factors.

Map of radon priority areas in Luxembourg.

The map published in 2016 shows that it is the northern part of the country that is most affected by radon. More than 5 % of the buildings in the five cantons shown in red have radon concentrations above the reference level of 300 Bq/m³. Where the rest of the country is concerned, 1-5 % of the buildings in the four cantons shown in yellow are above the reference level, and <1 % of the houses in the three cantons shown in green are higher than the reference level.

The reference level of 300 Bq/m³ is exceeded in more than 5 % of the homes in the 5 cantons in the north of the country (Clervaux, Wiltz, Vianden, Diekirch, and Redange).

_{Graph showing radon concentrations in houses as a percentage of the reference level for the cantons of Luxembourg (number of buildings per canton in which the radon concentration in the air was measured).}      

Study of measures conducted in winter 2016/2017

Study of routine measures

During winter 2016/2017, 221 homes were monitored, with 517 measurements taken in total. Most of the readings are between 100 Bq/m³ and 300 Bq/m³. The results of this study are in line with the radon map.

Study on new passive and low-energy homes

Alongside routine measures, the DRP has conducted a campaign to measure radon concentrations in recently built passive houses (label A) and low-energy homes (label B). During the campaign, radon concentrations were measured in 172 homes. As a general rule, these new buildings have been designed to be more airtight in order to reduce energy losses.

The results revealed that the average radon concentrations in these houses are lower than in traditional houses, particularly in geographical areas with average and high radon concentrations. Generally speaking, the marked differences that had been observed, both in traditional houses and in 2016 map of the country, are no longer observed. Sub-reference level measurements were recorded in three houses only, in the cantons of Clervaux, Mersch and Wiltz respectively.

_{Graph showing radon concentrations as a percentage of the reference level, in passive and low-energy homes, by canton, as measured by the DRP during the winter of 2016/2017. Number of houses per canton in which the radon concentration in the air was measured.}

Special case: In one house located in the canton of Clervaux, radon levels of more than 600 Bq/m³ were recorded during this study. As these readings were exceptional, this home was not included in the average. The high readings found here have been attributed to an anomaly in the design of the building, and more specifically to a leak in the fresh air intake duct. Vigilance during building work is therefore essential, as is using the services of experienced building professionals who are aware of the issues around radon.