Radon measurement quality, how accurate is reasonable?

Until 2006, continuous radon monitoring devices, CR, could either be calibrated by reference to known quantities or by internal adjustments and or alignments. In 2007, a policy was advanced by the National Radon Safety Board and the National Environmental Health Association mandating internal adjustment and or alignment. Further, calibrations could only be performed by radon chamber persons authorized by the specific device manufacturer, which was a process that was impossible for many chamber operators to achieve. The paper serves to examine the technical validity for routine internal adjustments to Honeywell and Sun Nuclear (Sun Nuclear Corporation, 425A Pineda Court, Melbourne, FL 32940-7508) devices in contrast to the clear market controlling advantages of the policy. The purpose for making radon measurements is to assess risk. Comparing the uncertainties associated with risk to counting uncertainties of Honeywell and Sun Nuclear CR devices, less than 1% of model 1027 devices would have a calibration error exceeding 25%, and those devices, at this Radon Measurement Proficiency limit, would produce results that were more precise and accurate than the radon risk uncertainty. This was true for CR devices that have not been internally adjusted nor corrected in any way. It was concluded that internal adjustment or alignment better supported business principles than science.