How far from the floor should radon measurement devices be placed when suspended from the ceiling?

The correct answer is that radon measurement devices should be placed 6 to 8 feet from the floor when suspended from the ceiling. This height is recommended because it aligns with the breathing zone of individuals who occupy the space, as radon tends to accumulate near the floor due to its density being greater than that of air. Placing the measurement devices at this height ensures that the readings accurately reflect the radon levels in a space where people are likely to be present and breathe in the air.

In contrast, other height options do not effectively capture a true representation of indoor radon levels. Placing devices too low, for instance at 1 to 3 feet or even 4 to 5 feet, may miss the more concentrated levels of radon, especially in areas with poor ventilation. The goal is to position the devices in a location where they can measure the air that people are actually breathing, which makes the 6 to 8-foot height the most suitable choice.