According to EPA estimates, every house has some amount of radon and 1 in 15 or 6.6% of US homes have an average indoor radon concentration of above 4pci/l.
So what is Radon? Radon is colorless. odorless, tastless, inert gas produced by the decay of Radon 226 and Uranium 238.
Where is Radon located? Radon has been found in every state in the US. It is typically found below grade in deposits of Uranium. Also it can be found in private water sources, such as wells, especially where limestone shale is prevalent. Additionally Radon may be found in some materials inside the house like grant counter tops, slate flooring, pool table tops, various concrete products and stone foundations.
Radon is the number one cause of lung cancer among non-smokers and radon the second leading cause of lung cancer. Radon is responsible for about 21,000 lung cancer deaths every year. About 2,900 of these deaths occur among people who have never smoked.
In 1987 the EPA established levels for exposure meditation. First the average indoor level is 1.3pci/l and 0.4 outdoor. The level requiring action is 4 pci/l or .02Wl. Between 3.9pci/l and 2pci/l are acceptable but remediation is suggested.
The EPA does not currently have a maximum contaminant level for drinking water. However the rule of thumb for public water is 200-400 Pic/l.
The basic mechanics of radon entry are first a radon source, then a path inside and finally a method of transport of force of drawing the soil air inside. Some of the potential sources have been covered above. Some potential entry routes in the house are through building openings such as holes and cracks in the floor or foundation, expansion joints, floating slab, plumbing chases/penetrations, sump pump pits, uncapped/filled block tops, uncapped floor drains, perimeter drain, structural failure, through solid concrete walls or slabs.
The main transport mechanism that transports Radon into the home is air pressure differential caused by air being exhausted by the building by ventilation. Other methods include concentration gradient diffusion from the soil to indoor air. Radon disperses through the soil from higher concentrations to lower and is also higher closer to the source. Soil concentrations are usually higher under the slab after snow or rain due to displacing the soil gases and creating hydraulic pressure and forcing Radon into the house.
We are currently using charcoal canisters for testing.