Metrology infrastructure for radon metrology at the environmental level

Since 2020 a large consortium has been engaged in the project EMPIR 19ENV01 traceRadon to develop missing traceability chains improve sensor networks climate observation and radiation protection. This paper presents results areas of: Novel 226Ra standard sources with continuous controlled 222Rn emanation rate, radon chambers aimed create reference atmosphere field for flux monitoring. The major challenge lies low activity concentrations of outdoor air from 1 Bq∙m-3 100 Bq∙m-3, where below there is currently no metrological at all. Thus, measured values different instruments operated locations cannot be compared respect their results. Whin this paper, new infrastructure presented, capable filling gap traceability. achieved make calibration services, far beyond state art, possible.