Radon Transport, Accumulation Patterns, and Mitigation Techniques Applied to Closed Spaces.

In this study, different techniques for the mitigation of radon gas in indoor spaces were investigated. For this purpose, two different scenarios of a public building were analyzed: two symmetrical facility galleries and a reverberation chamber. Although most workplaces in this building have low radon levels, the complex structure houses spaces have very high radon concentrations. The study also included the surrounding areas of these spaces. The radon concentration and differential pressures were measured, and different mitigation techniques were applied: sealing, balanced ventilation, pressurization with the introduction of fresh air, and depressurization over each space. The pressurization solution was proven to be the most effective way to reduce radon concentration in both scenarios. The introduction of fresh air diluted the radon concentration, and the slight increase in the pressure reduced the entry of gas by the advection mechanism. On the other hand, the depressurization technique was the least effective mitigation technique, as it generated a negative pressure gradient that facilitated a higher radon flux from the source. Therefore, before applying any mitigation technique, it is necessary not only to study the space to be remediated but also the possible impact on neighboring spaces.