What are the three major factors of radon entry into a home?

The three major factors of radon entry into a home are source strength, transport mechanisms, and ventilation rate. Source strength refers to the concentration of radon in the soil beneath and around a home, which is influenced by the geological characteristics of the area. Transport signifies how radon moves from the ground into a building, primarily through cracks, gaps, and other openings in the foundation. Ventilation rate pertains to how air circulates within and around the home, which can affect radon concentrations; a well-ventilated home may mitigate radon levels, while a poorly ventilated space can allow radon to accumulate.

The other choices present factors that do not directly correlate with how radon enters a home. Soil density and house age can affect overall structural integrity and potentially other environmental aspects, but they do not specifically address radon transport or concentration. Similarly, elements like humidity levels, building materials, wind direction, fire safety, and water drainage are not primary contributors to radon entry. Instead, they may relate to other environmental or structural considerations. Understanding these three major factors is essential for effective radon measurement and mitigation strategies.