Which factor does NOT affect indoor radon concentrations?

Indoor radon concentrations can be influenced by several environmental and structural factors, but the concentration of carbon dioxide in the surrounding air does not have a direct impact on radon levels inside a building.

Radon is a naturally occurring radioactive gas that primarily originates from the decay of uranium in soil and rocks. The strength of radon in the soil plays a crucial role in determining the potential radon levels in a building; higher radon concentrations in the soil can lead to increased levels indoors. The pathways for radon entry, such as cracks in the foundation, soil pores, or construction features, also significantly affect how much radon can infiltrate a home. Additionally, the ventilation rate of a dwelling is crucial because higher ventilation can help reduce radon concentrations by diluting the indoor air with outside air, which typically has lower radon levels.

In contrast, while carbon dioxide is a common indoor pollutant that can arise from human activity, its concentration does not influence radon levels. The mechanisms and sources of radon are entirely separate from those of carbon dioxide, making the presence or concentration of CO2 irrelevant to understanding indoor radon concentrations. This distinction highlights why the concentration of carbon dioxide in the surrounding air is not a factor that affects indoor radon levels