Which of the following radon mitigation techniques is most commonly used for single-family residences?

Active soil depressurization (ASD) is the most commonly used radon mitigation technique for single-family residences because it effectively reduces radon levels by creating a negative pressure beneath the home, thereby preventing radon from entering the living spaces. This method involves the installation of a fan that pulls air from beneath the foundation and discharges it above the roofline, ensuring that the radon gas is vented safely away from the home.

The effectiveness of ASD is supported by its ability to maintain lower radon levels consistently, making it the preferred choice among mitigation strategies. It is particularly advantageous in homes with high radon concentrations or in areas where radon levels in the soil are known to be elevated.

In comparison, although passive soil venting can be a less expensive option that relies on natural airflow to reduce radon levels, it may not be sufficient in all situations, especially in homes with significant radon gas intrusion. Sub-slab depressurization, while similar, typically refers to a more specific aspect of ASD and may not always encompass the full system and fan elements that characterize ASD systems. Building ventilation systems can help improve indoor air quality but are not specifically designed for radon mitigation, making them less effective for this purpose. Thus,