radon vent pipe 4
https://radontestingservicesden.vantagequill.com/posts/when-to-trust-professional-radon-testing-services-for-your-home
A radon vent pipe sticks out from the side of a house, often looking like a plain PVC pipe, but it's doing important work. It runs from a system under the concrete slab, pulling soil gas up and away from the home, then releasing it safely into the air above the roofline. Without it, radon gas can build up inside and pose a health hazard. You'll see them in newer construction or after a mitigation system is installed.