Uranium to Radon

• Uranium-238 passes through a sequence of five radioactive isotopes to form radon. These steps take varying degrees of time. The sequence begins with uranium-238 yielding thorium-234; thorium-234 yields protactinium-234; protactinium-234 yields uranium-234; uranium-234 yields thorium-230; thorium-230 yields radium-226; and radium 226 yields radon-222.
  Up until radon is produced, all the substances formed are solids. As such, they generally do no harm, as the radioactive decays are all non-gamma radiation, which cannot penetrate far, and all occur underground. None of that radiation reaches the surface. After that, it is a different story.
  
  

Radon Breakdown Sequence

• Radon-222 breaks down to polonium-218. Polonium-218 yields lead-214 (not stable). Lead-214 yields bismuth-214. Bismuth-214 yields polonium-214. Polonium-214 yields lead-210 (again, not stable). Lead-210 yields bismuth-210. Bismuth-210 yields polonium-210. Polonium-210 yields the stable isotope lead-206, ending the progression of radioactive decays. The complete sequence takes hundreds of thousands of years. None of the materials formed after radon breaks down are gases.
  
  

How Radon Enters Your Home

• Excessive Radon Areas
  
  Mountainous areas where granite exists, and certain mountain ranges in particular, give off radon gas molecules that come up through the earth and may escape into people's homes. In fact, radon is more widespread in its distribution than most people realize. If you live in a geographical region where radon is a particular problem, have your home tested for radon by a qualified tester.
  Two possible additional sources of radon are well-water and drywall made from materials from certain areas where contamination is abundant. The EPA indicates that as many as one out of every 15 homes may have elevated radon levels.
  Radon can come in through cracks in floors and construction joints. It can also come in through gaps around pipes.
  
  

Health Problems

• Radon causes various health problems. Gas atoms that enter your lungs can irradiate them, and over a period of time, lung cancer may result. Smokers who suffer radon exposure are at a special risk.
  
  

Prevention/Solution

• When purchasing a home, ask the seller about radon in the home and if the home has been tested. If not, make sure to do so yourself. Testing takes time, so if you wan to sell your home, it is wise to get testing ahead of time and any needed repairs accomplished before putting it on the market.