Radon levels can accumulate to high concentrations in your home. This depends on radon levels in the soil (the source), how radon enters the home (pathways), and pressure differences between the outside air and the inside air (air pressure) that drive radon into the home.
Source – In Minnesota, soil is the main source of radon, where it occurs naturally.
Pathways – Radon gas enters the home, usually through openings between the soil and the home. These pathways may include cracks in the concrete slab, floor-wall joints, an open sump pit, or a crawl space.
Air pressure – Differences in air pressure between the home’s interior and the soil can pull radon gas into the home through the pathways.