What does a short-term, closed-building test indicate about radon concentration?

A short-term, closed-building test is specifically designed to measure radon levels over a brief time frame, typically between 2 to 7 days, in a controlled environment where all windows and doors are closed. This method captures the peak radon concentrations that can occur due to various factors such as changes in atmospheric pressure, temperature, or humidity. The nature of these tests ensures that conditions are optimized to represent the highest possible radon levels.

In contrast, other options may imply a longer-term average (which a short-term test does not provide) or suggest outcomes that would not accurately reflect typical radon measurements. A short-term test is not a reliable indicator of future concentrations nor does it provide the lowest reading or average year-round levels. Therefore, it is most appropriate to understand that the results of such a test indicate the likelihood of encountering the maximum radon levels that could pose risks within a residential setting.