The Metrological Traceability, Performance and Precision of European Radon Calibration Facilities

Radon Exposure Concentrations in Finnish Workplaces

ABSTRACT

The aim of this study was to obtain information on the radon concentrations to which Finnish workers are exposed. Radon measurements were conducted as integrated measurements in 700 workplaces, supplemented by continuous radon measurements in 334 workplaces. The occupational radon concentration was calculated by multiplying the result of the integrated measurements by the seasonal correction factor and the ventilation correction factor (ratio between the working time and the full-time radon concentration obtained from continuous measurement). The annual radon concentration to which workers are exposed was weighted by the actual number of workers in each province. In addition, workers were divided into three main occupational categories (working mainly outdoors, underground, or indoors above ground). Probability distribution of the parameters affecting radon concentration levels were generated to calculate a probabilistic estimate of the number of workers exposed to excessive radon levels. With deterministic methods, the geometric and arithmetic mean radon concentrations in conventional, above-ground workplaces were 41 and 91 Bq m -3 , respectively. The estimated geometric and arithmetic mean annual radon concentrations that Finnish workers are exposed to were assessed as 19 and 33 Bq m -3 , respectively. The generic ventilation correction factor for workplaces was calculated as 0.87. Assessed with probabilistic methods, there are approximately 34,000 workers in Finland whose exposure to radon exceeds the reference level of 300 Bq m -3 . Although radon concentrations are generally low in Finnish workplaces, many workers are exposed to high levels of radon. Radon exposure in the workplace is the most common source of occupational radiation exposure in Finland.

Research summary of the EMPIR MetroRADON project

In this paper, a comprehensive overview on the achievements and generated research results beyond the state-of-the-art is given based on the working structure of the joint metrology research project MetroRADON. The results of the project have been targeted at the implementation of the European Council Directive 2013/59/EURATOM on radiation protection (EU BSS) and benefit European and international standards on radon monitoring, radon measurement and calibration, geographical radon mapping, and guidelines on radiological protection, construction products, radiation instrumentation and nuclear data.