What effect does a difference in air pressure between the basement or crawlspace and the surrounding soil have?

When there is a difference in air pressure between a basement or crawlspace and the surrounding soil, it can create a scenario where radon gas is actively drawn into the home. This phenomenon is primarily due to the natural tendency of air to move from areas of higher pressure to areas of lower pressure. If the pressure in the indoor environment (such as a basement or crawlspace) is lower than the pressure in the surrounding soil, the radon gas that is present in the soil can be pulled into the home to equalize the pressure difference.

This process highlights the importance of understanding air pressure dynamics in homes, especially in areas where radon is prevalent. It underscores why effective ventilation systems and building design considerations are vital for preventing radon buildup in living spaces. By addressing these pressure differences through proper sealing and ventilation, homeowners can significantly reduce the risk of radon exposure indoors.