What does a higher radon measurement on the first floor suggest about air pressure?

A higher radon measurement on the first floor suggests that the air pressure in the basement is lower than that in the soil. This phenomenon is related to the principles of air pressure differentials and how they affect radon entry into buildings.

When the pressure in the basement is lower than the surrounding soil, radon gas, which is naturally produced from the decay of uranium in soil and rocks, is drawn into the basement through cracks and other openings in the foundation. As a result, if the pressure is lower in the basement, it creates a vacuum effect that facilitates the upward movement of radon, potentially raising the concentrations of radon measured in the home.

In contrast, if the first floor had higher air pressure relative to the basement, it would discourage radon from migrating into the living spaces above. Understanding this relationship is crucial for effective radon mitigation strategies, as it highlights the importance of managing air pressure within the home to reduce radon entry.