What might occur due to the "stack effect" in a building?

The "stack effect" is a phenomenon that occurs in buildings where warm air rises and creates a difference in air pressure between the upper and lower parts of a structure. This effect can lead to the entry of outside air into the building, especially if the lower levels have a negative pressure relative to the outside environment. When this happens, any contaminants, including radon gas—which is naturally produced from the decay of uranium in soil and rock—can be drawn into the building from the ground.

As the warm air rises, it creates a vacuum at lower levels, which can pull air from the basement or foundation area where radon is often present. Therefore, an increase in radon entry can happen as a direct consequence of the stack effect occurring in a building. This phenomenon is especially relevant in regions where radon levels in the soil are significant, making it crucial for buildings to have proper ventilation and radon mitigation systems in place to reduce exposure risks.

The other choices do not accurately depict the outcome of the stack effect. For example, while decreased humidity could occur under certain conditions, it is not a primary consequence of the stack effect. Similarly, stable temperatures and improved air quality are not directly related to the ramifications of the stack effect and do not illustrate