Radon is a naturally occurring gas caused by the breakdown of uranium, which is found in many sub-soil locations in every state.  Because it is a gas, it moves through crevices in the rock and soils under homes and eventually into the home.  The EPA recommends that all homes be tested for radon, since radon is the second leading cause of lung cancer.  EPA had established the remediation action level of radon to be at or higher than 4 picocuries per liter of air.   The physics of the situation is relatively simple.  With operations of kitchen and bath fans, the interior of most houses have lower air pressure than the outside air, and especially pressures under the lowest floor slab.  Mother nature, on the other hand, rarely stops pumping subsoil gases into the voids under the slab, which causes pressures to build.  Gases move from areas of higher pressure into areas of lower pressure.  Think of low pressure giving the higher pressure air permission to enter.  Over time, radon gas builds in the lower areas of a house.  
Radon Remediation System in Place
  Once a property is tested for radon and elevated levels are discovered, remediation is appropriate to reduce the potential for radon causing lung cancer.  Radon remediation systems are designed to drastically lower the amount of radon in a home by significantly reducing the pressures under the lowest level slab, so the relative higher house pressure is now moving air into the sub-slab areas and not the visa-versa.  Typically a suction fan with piped from under the lowest level’s floor to outside, which both pulls radon out of the subsoil area before infiltrating into the home and lowers the air pressure down there.   There are several different equipment configurations used to solve an elevated radon problem.  The radon remediation staff of Alban Real Estate Services is fully trained with the construction experience to select the most effective system consistent with the lowest possible cost to our customer and perform the installation effectively with the minimum of disruption to the owner’s property. An estimated cost for a radon mitigation system is between $1,000 and $1,500.