More Facts About Radon
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Radon Discovery
A German chemist Friedrich Dorn discovered radon-222 in 1900, and named it radium emanation. The United States medical experts did not became aware of a radon problem until 1984, when a nuclear plant employee in Pennsylvania discovered radioactivity on his clothing while exiting his work through radiation detectors. The source radiation was determined to be radon on his clothing originating from his home.
Radon in our Environment
Radon-222 is the decay product of radium-226. Radon-222 and its parent, radium-226, are part of the long decay chain for uranium-238. Since uranium is essentially everywhere in the earth's crust, radium-226 and radon-222 are present in almost all rock and all soil and water.
Radon Properties
Radon is heavy gas that does not combine with other chemicals, which explains why it tends to collect in basements or other low places in homes and buildings. It has no color, odor, or taste. Radon-222 is formed by the decay of radium, has a half-life of 3.8 days, and emits an alpha particle as it decays to polonium-218, and eventually to stable lead. Radon-220, is the decay product of thorium which is sometimes called thoron, and has a half-life of 54.5 seconds. It emits an alpha particle in its decay to polonium-216.
Radon Levels
Radon is found in low concentrations in almost all rock and soil. Radon is generated in rock and soil, and it makes its way through crack between particles and escapes into the outside air. Radon can move easily through rock and soil and arrive at the surface. Individuals may ingest trace amounts of radon with food and water, however, inhalation is the main route of entrance into the body.
There is no safe level of radon. Any exposure poses some risk of cancer. In two 1999 reports, the National Academy of Sciences concluded that radon in indoor air is the second leading cause of lung cancer in the U.S. after cigarette smoking. The NAS estimated that 15,000-22,000 Americans die annually from radon-related lung cancer. Almost all risk from radon comes from breathing air with radon and its decay products that cause lung cancer. An estimated 180 cancer deaths annually are caused by radon in drinking water, however almost 90% of those deaths are from lung cancer through the inhalation of radon released to the indoor air from water, and only about 10% were from cancers of internal organs, mostly stomach cancers, from ingestion of radon in water.
Although outdoor levels of radon are typically low, about 0.4 picocuries per liter (pCi/l) of air, it can seep into buildings through foundation cracks or openings and build up to much higher levels indoors. Average indoor radon levels are about 1.3 pCi/l of air. However it is somewhat common for indoor levels to be found in the range of 5 - 50 pCi/l, and have been found as high as 2,000 pCi/l. The levels of radon measured in a house or building depends on many factors, including the design, geology, soil conditions, and weather. Radon's decay products are all metallic solids, and when radon decay occurs in air, the products can cling to aerosols and dust, which makes them easily available for inhalation into the lungs. All homes should be tested for radon!
Radon is also found in the water of many homes, in particular, those that have their own well rather than using the municipal water supply. When this water is agitated, as when showering or washing dishes, radon escapes into the air. However, radon from domestic water comprises only a small proportion (less than 1%) of the total radon gas in homes. Municipal water systems hold and treat water, which releases radon, so levels are very low by the time the water reaches our homes. But, people who have private wells, particularly in areas of high radium soil content, may be exposed to higher levels of radon, and should conduct a Radon Water Test ASAP!
Radon Exposure
Most of the public is exposed to natural radiation from radon gas, which can be found in homes, schools, and office buildings. The EPA estimates the national average indoor radon level in homes is about 1.3 pCi/l of air. About 1 in 15 homes nationwide have levels of the 4 pCi/l or higher. The 4pCi/l level is where the EPA recommends taking immediate action to reduce concentrations. Levels as high as 2,000 pCi/l have been measured in some homes.
Most of the radon gas you inhale is also exhaled. However, some of radon's decay products attach to dust and aerosols in the air and are deposited in your lungs. Some Radon is cleared out by the lung's natural defense system, and swallowed or coughed out. Those particles that are left over release radiation, damaging the surrounding lung tissues. A small amount of radon decay products in the lung are absorbed into the blood. Radon and its decay products that are in drinking water quickly lose their energy and are taken up by other compounds in water, and do not pose a health concern.
Protection
You cannot see, feel, smell, or taste radon. Testing your home is the only way to know if you and your family are at risk from radon. EPA and the Surgeon General recommend testing for radon in all rooms below the third floor. EPA also recommends testing in schools.
Radon testing is relatively inexpensive and easy to do! Millions of Americans have already tested their homes for radon. The first step is to test your home for radon, and take action if levels are at or above 4 picocuries per liter. You may want to take action if the levels are in the range of 2-4 picocuries per liter. Usually, levels can be brought below 2 pCi/l fairly easily.
If your home tests high for Radon, the best method for reducing levels will depend on how radon enters your home and the design of your home. We Strongly Recommend hiring a Licensed and Certified Radon Mitigation Specialist. This Usually costs between $800 and $2,500. You can try it yourself if you have the time and technical know how.
Medical Tests
Several Radon decay products can be detected in urine, blood, lung and bone tissue. However, these tests are not readily available through typical medical facilities, and cannot be used to determine exposure levels, since most radon products deliver their dose and decay within a few hours. The best way to determine exposure to radon is by measuring concentrations of radon in the air you breathe.
EPA Recommendations
In 1988, EPA and the U.S. Surgeon General issued a Health Advisory recommending that all homes be tested below the third floor. They also recommended fixing homes with radon levels at or above 4 picocuries per liter (pCi/L), EPA's National Voluntary Action Level. EPA and the Surgeon General also recommend that schools nationwide be tested for radon.
