What is Radon
Radon is a colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. Radon gas is one of the heaviest substances that remains a gas under normal conditions and is considered to be a health hazard. The most stable isotope, Radon Gas, has a half-life of 3.8 days and is used in radiotherapy. While having been less studied by chemists due to its radioactivity, there are a few known compounds of this generally un-reactive element.
Radon is a significant contaminant that affects indoor air quality worldwide. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement. It can be found in some spring waters and hot springs.
According to the United States Environmental Protection Agency, radon is reportedly the second most frequent cause of lung cancer, after cigarette smoking; and radon-induced lung cancer the 6th leading cause of cancer death overall. According to the same sources, radon reportedly causes 21,000 lung cancer deaths per year in the United States. Because of this, radon mitigation systems can be life-savers.
Indoor radon can be mitigated by sealing basement foundations, water drainage, or by sub-slab de-pressurization. In severe cases, mitigation can be achieved via air pipes and fans to exhaust sub-slab air to the outside. Indoor ventilation systems are less visible, but exterior systems can be more cost-effective in some cases. Modern construction that conserves energy by making homes air tight exacerbates the risks of exposure if radon is present in the home. Older homes with more porous construction are more likely to vent radon naturally. Ventilation systems can be combined with a heat exchanger to recover energy in the process of exchanging air with the outside. (This is more common with commercial and industrial radon mitigation.) radon collector installed under a barrier (a sheet of plastic that covers the crawl space).
The most common approaches are active soil depressurization (ASD) which utilizes a radon mitigation suction fan to pull the gas out from below the foundation of the home. The radon fan is attached in-line with a PVC pipe system running from the foundation to the roof of the home. Once the radon gas is discharged outdoors, it becomes diluted by the outdoor air to levels that are not hazardous.