radon vent pipe 4

https://radontowncountryjournal.silverstonebrief.com/posts/radon-town-and-country-what-west-st.-louis-county-homeowners-need-to-know

The radon vent pipe sticks up from the ground near the foundation, usually a white PVC pipe capped with a metal screen to keep debris and critters out. It's part of a mitigation system that draws soil gas from below the slab and releases it safely above the roofline, preventing radioactive gas from seeping into living spaces. That simple pipe is a quiet but crucial barrier between your home and potential health risks.