four principal ways of reducing the amount of radon accumulating in a house are: Sub-slab depressurization (soil suction) by increasing under-floor ventilation; Improving the ventilation of the house and avoiding the transport of radon from the basement into living rooms; Installing a radon sump system in the basement; Installing a positive pressurization or positive supply ventilation system. According to the EPA, the method to reduce radon "...primarily used is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside", which is also called sub-slab depressurization, active soil depressurization, or soil suction. Generally indoor radon can be mitigated by sub-slab depressurization and exhausting such radon-laden air to the outdoors, away from windows and other building openings. "[The] EPA generally recommends methods which prevent the entry of radon. Soil suction, for example, prevents radon from entering your home by drawing the radon from below the home and venting it through a pipe, or pipes, to the air above the home where it is quickly diluted" and the "EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently". Positive-pressure ventilation systems can be combined with a heat exchanger to recover energy in the process of exchanging air with the outside, and simply exhausting basement air to the outside is not necessarily a viable solution as this can actually draw radon gas into a dwelling. Homes built on a crawl space may benefit from a radon collector installed under a "radon barrier" (a sheet of plastic that covers the crawl space). For crawl spaces, the EPA states "An effective method to reduce radon levels in crawl space homes involves covering the earth floor with a high-density plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the outdoors. This form of soil suction is called submembrane suction, and when properly applied is the most effective way to reduce radon levels in crawl space homes." See also International Radon Project Lucas cell Pleochroic halo (aka: Radiohalo) Radiation Exposure Compensation Act References External links Radon and radon publications at the United States Environmental Protection Agency National Radon Program Services hosted by Kansas State University UK maps of radon Radon Information from Public Health England Frequently Asked Questions About Radon