Radon is a radioactive, colourless, odourless, tasteless noble gas, which occurs naturally through geological based processes. Despite its short half-life of 3.8 days, radon gas from natural sources can accumulate in buildings, particularly in confined or unventilated spaces. Radon is estimated to cause between 3 % and 14 % of all lung cancer cases, depending on the average radon level in the country (WHO, Fact sheet N°291, 2014). For Europe, this corresponds to around 15,000 to 20,000 people per year dying of lung cancer caused by radon exposure.
The European Council Directive 2013/59/EURATOM (EU-BSS), which is in the process of transposition into national legislation in EU member states, lays down legal limits for radon concentrations in indoor air. The maximum limit set by the EU-BSS is 300 Bq/m3, hence a significant improvement in the metrological infrastructure in Europe in the field of radon calibrations at low activity concentrations is a prerequisite in order to be able to fulfil the EU-BSS requirements. New procedures and traceable radon reference sources for the traceable calibration of radon measurement instruments at low activity concentrations with adequately low uncertainties therefore need to be developed. Thoron and its progeny are known to bias the results of radon activity concentration measurements, however information about this effect is limited. Therefore better knowledge of this effect is needed together with techniques to reduce the influence of thoron and its progeny on radon end-user measurements and calibrations. Traceability and quality assurance of calibrations of radon monitors and of radon calibration facilities, as well as the development of methods to conduct a large number of traceable and quality assured in-situ and laboratory measurements of radon are required.
EU member states are obliged to consider several aspects when preparing their national radon action plan, which is a strategy for conducting surveys of indoor radon concentrations. To ascertain that the required level of safety is met for all European citizens, the consistency of indoor radon measurements and soil radon exhalation rate measurements across Europe need to be optimised. Therefore, identification of radon priority areas is necessary, in order to take appropriate measures for the protection of the public.
For the reduction of trade barriers and the mutual recognition of calibration certificates, general guidelines and recommendations on calibration and measurement procedures for the determination of radon concentration in air have to be established. This will be facilitated by the uptake of the project’s results in the standards developing organisations and furthermore, by the end-users.
This is a joint research project carried out in the framework of the European Metrology Programme for Innovation and Research (EMPIR) (see:http://www.euramet.org/research-innovation/empir/). The EMPIR initiative is co-funded by the European Unions's Horizon 2020 research and innovation programme and the participating states. METAS is one of the project partners in the Project.
