What is the primary factor that determines a home's radon source strength?

The primary factor that determines a home's radon source strength is the radium concentration in the soil. Radon is a naturally occurring radioactive gas that is produced from the decay of uranium, which is found in varying amounts in the soil and rocks. Areas with higher radium concentrations will generally result in higher levels of radon being emitted from the ground into the home.

As radium decays, it produces radon gas, which can seep into buildings through cracks in foundations, walls, and other openings. Therefore, the geologic characteristics of the area, particularly the amount of radium present in the soil, play a significant role in the potential radon risk for a home. Understanding the local geology can help in assessing the radon risk before or during home construction and for existing homes as well.