Field comparison of commercially available short-term radon detectors.

We performed a comparison of commercially available short-term radon detectors in order to determine the accuracy and precision of the detectors under actual field conditions. We exposed fifteen radon detectors, under field conditions, from each of six companies to a reference radon concentration. Five of the six companies tested did not pass the U.S. Environmental Protection Agency's previously established accuracy guideline (all individual relative errors </= 25%) and four of the six companies failed the EPA's precision guideline [coefficient of variation </= 10% at 150 Bq m (4 pCi L)]. The findings suggest that the performances of commercially available radon detectors exposed under actual field conditions may not be as accurate or precise as those detectors available prior to the close of the EPA's National Radon Proficiency Program in 1998. It is unknown if this one-time "snap shot" represents the overall reliability of the accuracy and precision of commercially available radon detectors. Nonetheless, the findings suggest that additional double-blind testing of commercially available radon detectors under actual field conditions is warranted.