Objective To establish a process for intercomparison test for the detection methods for radon among la boratories in order to help them identifying systematic varaiances so as to improve the technical proficiency and to secure the reliability of test results.
Methods Stability and uniformity tests of radon concentration were conducted on the testing environment for selecting the stability parameters appropriate for intercomparison test. Seven radon detectors in six laboratories were used for intercomparison analysis of radon in environmental air according to the National Standard on the Measuring Method for Radon in Environmental Air (GB/T 14582-1993), the Industry Standard on the Measuring Method for Radon in Air by Scintillation Flask by the Ministry of Health(GBZ/T 155-2002), as well as the National Standard on Proficiency Testing by Interlaboratory Comparisons-Part 1:Development and Operation of Proficiency Testing Schemes. The results of intercomparison tests were evaluated using robust statistics.
Results The results of intercomparison tests evaluated with robust statistics showed that the median was 217 Bq/m3, robust CV was 14.3%, standard IQR 31.1 Bq/m3, maximum 236 Bq/m3, minimum 85 Bq/m3, and variation was 151 Bq/m3. Five radon detectors out of the seven were found to be satisfactory, one detector was questionable (Z-score:-2.28)and another one unsatisfactory (Z-score:-4.24).
Conclusion It is concluded that the detection results using different detection methods or different patterns of equipments are basically comparable through the intercomparison results of detection of radon levels in environmental air among different laboratories. The accuracy and the reliability of the results of low level radon detection in environmental air are improved through intercomparison among the laboratories.
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