How do continuous monitors record radon levels?

Continuous monitors for radon measurement are designed to track and record variations in radon levels over time by detecting ionized radiation. Radon gas itself is radioactive and emits alpha particles as it decays. Continuous monitors utilize sophisticated sensors to detect these alpha particles and other forms of radiation emitted from radon decay products.

These sensors convert the detected radiation into an electronic signal, which can then be measured and displayed as radon concentration levels. This detection process allows the equipment to provide continuous readings, making it effective in assessing the potential exposure to radon over extended periods.

The other methods mentioned, such as chemical reactions, physical weight changes, or measuring electrical resistivity, do not appropriately describe how radon monitoring devices function. Liters of the particulate matter and ionization process involved with radon gas make the detection of ionized radiation the most reliable and direct approach to continuous radon monitoring. Thus, the correct answer highlights the fundamental operational principle behind these essential tools in radon measurement.