In which situation would a long-term test be preferred over a short-term test?

A long-term test is preferred when the goal is to reflect seasonal variations in radon levels because radon concentrations can fluctuate based on various factors such as weather conditions, building usage, and ventilation practices. Long-term tests, which typically last from 90 days to a year, provide a more accurate representation of the average radon levels over time, capturing changes that can occur due to these variables.

In contrast, short-term tests, while useful for quick assessments or to obtain immediate results, do not provide the comprehensive data needed to understand fluctuations across different seasons or conditions. Therefore, for assessing the true average radon exposure in a home or building, a long-term test is essential.