A month ago I wrote about the installation of a radon mitigation system in my home. Before the install, the level in the basement measured 12.1 pCi/L , while the level on the first floor measured 6.0 pCi/L.
After the installation of the active mitigation system, the level on the first floor of the house was reduced to 2.6 pCi/L, as measured with a charcoal detector made by Air Chek. I haven’t rechecked the basement yet.
In addition to the lower radon reading, I’ve noticed that the basement humidity averages about 65%, and doesn’t rise much even after a good rain. That might make for the most useful result: no more soggy cardboard storage boxes.