sub-slab depressurization 3

https://myradonmitigationstlouisscope.brightpathdigest.com/posts/what-to-expect-from-radon-mitigation-st-louis-homeowners-should-know

Sub-slab depressurization is a method used to prevent soil gases like radon from entering a building by creating a vacuum beneath the concrete floor slab. A pipe system is installed, connected to a fan that pulls air from below the slab and vents it safely outside. It's not dramatic—just a quiet, continuous suction that keeps indoor air cleaner.