Importance of Discriminative Measurement for Radon Isotopes and Its Utilization in the Environment and Lessons Learned from Using the RADUET Monitor.

Chutima Kranrod,Yuki Tamakuma,Masahiro Hosoda,Shinji Tokonami

doi:10.3390/ijerph17114141

Abstract

Radon (222Rn) and thoron (220Rn), sources of natural background radiation, have been the subjects of long-standing studies, including research into radon and thoron as major causes of lung cancer at domestic and international levels. In this regard, radon and thoron measurement studies have been widely conducted all over the world. Generally, the techniques used relate to passive nuclear track detectors. Some surveys have shown that passive monitors for radon are sensitive to thoron, and hence some measured results have probably overestimated radon concentrations. This study investigated radon and thoron measurements in domestic and international surveys using the passive radon–thoron discriminative monitor, commercially named RADUET. This paper attempts to provide an understanding of discriminative measurements of radon isotopes and to present an evidence-based roadmap.

Highlights

Radon (222 Rn) is a noble gas generated from materials including radium (226 Ra) (a decay product of uranium (238 U)) such as rocks, soil, water and building materials
The World Health Organization recommended that a radon concentration of 100 Bq m−3 should be used as a national reference value and stated that this value was justified from a public health effect perspective [1]
The results showed that the mean radon concentration was 579 Bq m−3; in some cases, the thoron concentrations were not negligible and indicated that radon measurements which are sensitive to thoron could be misleading

Summary

Introduction

Radon (222 Rn) is a noble gas generated from materials including radium (226 Ra) (a decay product of uranium (238 U)) such as rocks, soil, water and building materials. The World Health Organization recommended that a radon concentration of 100 Bq m−3 should be used as a national reference value and stated that this value was justified from a public health effect perspective [1]. Even if it cannot be implemented, the chosen reference level should not exceed 300 Bq m−3 which corresponds to 10 mSv of effective doses per year based on the calculations by the International Commission on Radiological Protection (ICRP) [3]. Radon and thoron should be discriminatively measured for an accurate dose assessment and for future lung cancer risk assessment due to indoor radon [6]. This article presents a summary of the passive radon–thoron discriminative monitors known as RADUET and their applications in studies worldwide

Summary of RADUET

Lessons Learned on Radon and Thoron Measurement by the RADUET

Discussion

Conclusions