What is one common pathway for radon entry into buildings?

One common pathway for radon entry into buildings is through foundation openings to the soil. Radon, a radioactive gas produced from the natural decay of uranium found in soil and rock, can easily move through porous materials like soil. When buildings are constructed, they often have foundations that are in direct contact with the ground. If there are any openings, cracks, or gaps in the foundation, radon gas can seep in from the surrounding soil environment. This makes foundation openings a significant entry point for radon, especially in areas where radon levels are known to be high.

In contrast, while wall insulation, roof leaks, and air conditioning ducts might influence ventilation and airflow within a building, they are not primary entry points for radon. Wall insulation may help control the temperature but does not provide a direct pathway from the ground into living spaces. Roof leaks may allow moisture and water entry but are not typically associated with the gas transmission from below. Likewise, air conditioning ducts can circulate air within a building but are not designed for the purpose of allowing radon gas to enter from the foundation. Therefore, understanding the role of foundation openings is crucial for effective radon mitigation strategies.