Radon metrology for use in climate change observation and radiation protection at the environmental level

Radon gas is the largest source of public exposure to naturally occurring radioactivity, and concentration maps based on atmospheric measurements aid developers to comply with EU Safety Standard Regulations. Atmospheric radon can also be used as a tracer to evaluate transport models important for supporting successful greenhouse gas (GHG) mitigation strategies. One of the most common techniques currently applied for this propose is the Radon Tracer Method (RTM). To increase the accuracy of both radiation protection measurements and those used for GHG modelling, traceability to SI units for radon exhalation rates from soil, its concentration in the atmosphere and validated models for its dispersal are needed. Thus, atmospheric networks such as the Integrated Carbon Observation System (ICOS) are interested in integrating atmospheric radon concentration measurements. The EMPIR project 19ENV01 traceRadon[1] started to provide the necessary measurement infrastructure for atmospheric radon activity concentration and radon flux measurements, with benefits for both large scientific communities. This is particularly important for GHG emission estimates that support national reporting under the Paris Agreement on climate change.

Compared to the large spatiotemporal heterogeneity of GHG fluxes, radon is emitted almost homogeneously over ice-free land and has a negligible flux from oceans. Atmospheric measurements of radon activity concentrations can be used for the assessment and improvement of atmospheric mixing and transport models.

Similarly, for radiological data, all European countries have installed networks of automatic gamma dose rate and atmospheric concentration level monitoring stations and report the information gathered to the European Radiological Data Exchange Platform (EURDEP). Currently, EURDEP exchanges real-time monitoring information from 39 countries collected from more than 5500 automatic surveillance systems. Therefore, improving contamination detection requires greater accuracy in determining environmental radon concentrations and their movement in the atmosphere.

An overlapping need exists between the climate research and radiation protection communities for improved traceable low-level outdoor radon measurements, combining the challenges of collating and modelling large datasets, with setting up new radiation protection services. The project traceRadon works on this aspect for the benefit of two large scientific communities. An overview will be presented, and first results with respect to radionuclide metrology will be discussed.

[1] This project has received funding from the EMPIR programme co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme. 19ENV01 traceRadon denotes the EMPIR project reference.