Radon is undetectable by humans without using special equipment to measure its concentration. Radon results are measured and reported in either picocuries per liter (pCi/L) or working levels (WL). The Environmental Protection Agency (EPA) has set 4 pCi/L or 0.02 WL as the acceptable limits for Radon gas in the home. Any readings above this are considered hazardous. There are a variety of methods for testing Radon but the guidelines enumerated in the EPA's Radon Measurement Proficiency Program (RMP) should be followed to insure the most accurate test results. Each state has Radon office that can assist in answering questions. Normally, the Department of Environment or Air and Radiation Management handle Radon questions.

Just how Radon enters the home can vary. Radon typically moves up through the ground, through cracks and other holes in the foundation, slab, sump pump openings, floor drains, and pores in hollow brick walls to name a few. Radon can also seep into ground water coming from wells and remain trapped there, entering the home in the water being pumped from the well. Those on municipal water supplies do not have as much risk from this type of problem.

Radon can be present in any home new or old, well sealed or drafty, and with or without basements. Because Radon is a gas, it concentrates most efficiently in the areas of the home closest to the ground. Radon levels generally decrease as one moves higher in the structure. It is believed that nearly one out of every fifteen homes in the United States is estimated to have higher Radon levels. Because people spend most of their time at home, this is the most likely place for their greatest radiation exposure. The EPA's risk assessments assume an individual is exposed to a given concentration of Radon over a lifetime of roughly 70 years, and spends 75 percent of his or her time in the home.

Radon is harmful because it breaks down into radioactive particles (called decay products). When inhaled, Radon is trapped in the lungs where it decays emitting radioactive particles that adversely affect the cells in the lungs contributing to the development of lung cancer. Being a smoker exacerbates the effects. The EPA estimates that the risk of dying from lung cancer is as the result of an annual radon level of four picocuries is equivalent to the risk from smoking two packs a day while a level of 100 pCi / L equates to 2,000 chest x-rays a year. Radon is not a serious problem outdoors because it is diffused by the ambient air. The EPA has determined that short-term exposure to a high concentration of Radon is not as severe a risk as long-term exposure to lower levels of the gas. It is estimated that most homes will contain from one to two picocuries of Radon per liter of air. If a Radon test indicates Radon over four pCi / L, a long-term retest should be considered. If Radon levels continue to be high (over 4 pCi/L) there are a variety of effective and fairly inexpensive methods the homeowner can pursue.

When trying to deduce where Radon may be entering the house, the first and most likely suspects are all openings, cracks, or bare dirt areas. Cracks in the foundation, slab and walls may be allowing Radon to enter. These cracks should be filled and monitored to insure they do not reopen thereby allowing Radon to reenter. Uncovered sump pumps pit are another prime candidate for allowing Radon encroachment. Covers can be purchased to cover the pit and stop the Radon from entering. Gaps in suspended floors and around service pipe entries should be eliminated as Radon can enter through these. Another area to check is the water supply. Radon gas can be carried into the house from the well and cause high readings. If it is believed that the water may be carrying the Radon into the house, the water can be tested and if necessary filtered to stop the Radon entry. If these steps do not help, a professional Radon remediator should be called.

If the need for a professional Radon contractor arises, be sure they have a Radon Contractors Permit (RCP) issued by the EPA and is registered with the state as a certified Radon contractor and have their credentials with them before beginning work. It does not hurt to shop around and obtain the best quote for having the necessary work performed.

Radon gas can be found throughout the United States. Although it is more prevalent the closer one lives to mountainous regions, Radon can be found everywhere and should be considered an environmental hazard that should be checked for periodically and remedied if found to be present over 4 pCi / L. The national hotline for Radon testing information is 800SOS-RADON. Another source for Radon information is the Consumer Federation of America's (CIA) Radon Fix-It program, 800.644.6999. These are helpful people who can help with choosing a remediation company and other non-technical question.