radon in old rowhouses 6

https://oscar-wiki.win/index.php/Understanding_the_Pennsylvania_Radon_Action_Level_for_Safer_Homes

radon in old rowhouses: That musty basement smell might be more than just old dust. Many of these brick homes were built right on the ground, with cracked slabs and dirt crawl spaces that let soil gas seep in. A quick test kit from the hardware store is all it takes to see if your family is breathing in this invisible, radioactive intruder.