Which of the following is NOT a measurement method for radon detection?

The passive tubing method is not recognized as a formal measurement method for radon detection. While there are several well-established methods for measuring radon levels, such as using a charcoal liquid scintillation device, an alpha track detector, and an electret ion chamber, the passive tubing method does not conform to these standard practices.

Charcoal liquid scintillation devices are widely used for short-term measurements and work by capturing radon gas in charcoal that then emits scintillations, which can be measured. Alpha track detectors, on the other hand, use a special film that records the tracks left by alpha particles emitted from radon decay, providing long-term radon concentration data. Electret ion chambers also serve as passive detectors, where ionization caused by alpha particles from radon is measured to determine radon levels.

The absence of a recognized methodology for the passive tubing method highlights its unreliability or lack of standard implementation within the field of radon measurement. By identifying this distinction, it is clear why this choice is not considered an appropriate method for detecting radon levels compared to the others listed.