A colorless, odorless, radioactive gas.
Being exposed to radon for a long period of time can lead to lung cancer. Radon gas in the air breaks down into tiny radioactive elements (radon progeny) that can lodge in the lining of the lungs, where they can give off radiation. This radiation can damage lung cells and eventually Radon is a gas that occurs naturally from the breakdown—or the radioactive decay—of uranium. Rocks, soil, and in some cases groundwater can all contain uranium. Because radon comes from so many sources, people are easily exposed to it. Radon is a colorless, odorless, radioactive gas. It forms naturally from the decay (breaking down) of radioactive elements, such as uranium, which are found in different amounts in soil and rock throughout the world. Radon is a naturally occurring radioactive gas that is colorless, odorless, and tasteless. It is formed by the natural breakdown of uranium in rock, soil and water. Radon gas moves up through the soil and can be drawn into our homes by slight pressure differences. Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as a decay product of radium. Its most stable isotope, 222Rn, has a half-life of 3.8 days. Radon is one of the densest substances that remains a gas under normal conditions. Radon is a chemically inert, naturally occurring, radioactive gas. It has no smell, colour, or taste, and is produced from the natural radioactive decay of uranium which is found in rocks and soil. Radon is a naturally occurring radioactive gas and comes from the natural breakdown (radioactive decay) of uranium. It is usually found in igneous rock and soil, but in some cases, well water may also be a source of radon. Radon is a naturally occurring radioactive gas that is invisible, odorless, and tasteless. It comes from the radioactive decay of radium, an element found in most rocks and soils. Radon can enter a building from the ground underneath it, and concentrate to tens or even hundreds of times the level in outdoor air. Radon is a radioactive gas released from the normal decay of the elements uranium, thorium, and radium in rocks and soil. It is an invisible, odorless, tasteless gas that seeps up through the ground and diffuses into the air.
http://www.cancer.org/cancer/cancercauses/othercarcinogens/pollution/radon http://www.cdc.gov/nceh/radiation/brochure/profile_radon.htm http://www.cancer.org/cancer/cancercauses/othercarcinogens/pollution/radon http://public.health.oregon.gov/HealthyEnvironments/HealthyNeighborhoods/RadonGas/Pages/index.aspx https://en.wikipedia.org/wiki/Radon http://www.who.int/ionizing_radiation/env/radon/en/ http://www.radon.com/radon/radon_facts.html http://www.doh.wa.gov/CommunityandEnvironment/Contaminants/Radon http://www.cancer.gov/about-cancer/causes-prevention/risk/substances/radon/radon-fact-sheet
radon is