48 hour radon test 5

https://astro-wiki.win/index.php/Understanding_the_EPA_Radon_Action_Level_and_What_It_Means_for_St._Louis_Homeowners

A 48 hour radon test is a quick way to check your home for this radioactive gas. You place a small detector in the lowest lived-in area, leave it undisturbed for two days, then mail it to a lab for analysis. It gives a snapshot of radon levels, but because levels can change, longer tests are more reliable.