At a nuclear facility in Pennsylvania, workers started testing for higher levels of radioactivity when they got to work rather than when they left work. This riddle led to further investigation and found that the levels of radioactivity were higher in their homes than at work. This, along with information about certain miners developing lung cancer, started health workers on the path to radon testing of homes.
Radon is a colorless, tasteless, invisible radioactive gas that is released from uranium. As Uranium decays and one of the products of that decay, is a radioactive gas called radon. Uranium is present at many locations throughout the world but when the amount beneath a home, or any building, is significant, radon gas accumulates inside that building exposing the occupants to radioactive related problems. Some areas tend to test high for radon, and of course, some areas test low for radon. The radon is measured in a test for radioactive material, picocuries per liter (pCi/L). The United States Environmental Protection Agency (EPA) has established the measurement of 4 pCi/L as the action level. The action level is the point where measurements are taken and if a measurement of 4 pCi/L or more is found, it is recommended that steps be taken to lower the radon levels within a building. More than one test is generally performed if the readings are higher than 4 pCi/L, to insure a correlation between tests exists.
Most buildings are under a negative pressure meaning the pressure inside a home is less than the outside surrounding areas. For example, when exhaust fans are operated or heating systems is operated, air is either discharged from the exhaust fan itself or out a chimney. This creates a slight vacuum. Unless the building is fitted with a heat recovery ventilator (an air to air heat exchanger), open a door on a cold day and the cold is being pulled inward, due to negative pressure. So radon gas is pulled into a house from the soil levels surrounding the house. A building with a full basement has five surfaces to collect radon beneath grade, the basement floor and four basement walls. Radon migrates through even the best sealed concrete surfaces with perimeter drains, small cracks, sump pits, and other penetrations only allowing freer air and gas flow. A building on a slab has only one area to collect radon but that only lowers the risk, not eliminate it. There is still one surface to collect or draw the radon gas through, and if sufficient, that one surface may draw serious quantities of radon. Occasionally, the ground may be low in radon concentrations yet the materials used to construct the building are high in uranium content. Stone, aggregate and often course fill material may contain uranium. It is currently believed that some granite countertops tend to have high uranium contents and therefore produce elevated radon levels. Crawlspaces may also collect radon depending on the method and types of ventilation systems installed. Each home with a crawlspace must be evaluated separately.
The lowest level of a home whether a basement or a house on a slab, is the areas where radon is generally at the highest levels. The basement location is generally where the heating systems are placed and forced air heating systems may collect and distribute radon quite effectively throughout a home, under the right conditions.
Being a radioactive gas, radon is drawn into the body when breathing and collected in the lungs. Radon is believed to be the second leading cause of lung cancer with smoking being the first. Long term radon exposure is dangerous according to the EPA. Walking into a home with elevated radon levels would not be a cause of concern, as long term exposure is the important term to remember. Similar to smoking, stealing a cigarette when young will not be a cause of concern but a lifetime of smoking is a concern. So eliminating radon is important enough for the EPA to provide information pertaining to radon. All homes can be tested.
Finding radon in a home does not exclude the home from being occupied as remediation is the answer to a radon problem. Just about every home with an elevated radon level can be remediated. Various systems are installed with a depressurization system being one of the most common. A depressurization system is composed of a series of piping connected to a fan. Holes are drilled through the concrete floor of a house on a concrete slab or concrete basement floor, and PVC plastic piping is inserted through the holes and connected together. The piping is then extended either to the exterior of the building, up existing walls, or up through the house. Usually the piping is located in the garage, closet spaces or a corner of a room, to be enclosed later. The piping is brought into the attic, a fan is installed, and the piping extended through the roof. If the piping is extended to the exterior at the basement level, a fan is installed in the piping above grade level, and the piping extended above the roofline. The fan is connected to pull air from beneath the house and draw that air, with the elevated radon levels, up through the piping and discharged to the exterior air. The radon is diluted in this manner and rendered harmless. State health departments have established radon mitigation licensing requirements and keep lists of those licensed to install the removal systems for the general public. Most experienced radon mitigation contractors have learned through that experience how to get a radon system functioning at peak performance even under unusual conditions or circumstances.
Radon testing is often performed when a house is sold by a home inspector or a radon testing and mitigation company, prior to closing. There are a number of different methods to test for radon with short term tests to long term tests. The actual readings are generally performed by a licensed laboratory, where an individual acting as a laboratory or a large firm, regardless of the testing method.
Some state health departments may offer radon tests for a very reasonable cost for homeowners that have not already tested for radon. Read the directions for the testing requirements carefully and follow the directions for an accurate test. All homeowners should take advantage of the offers soon from these state agencies, as the offers may become obsolete with the current budget problems. If the state is not offering radon test kits, call your local building material supplier to see what they may have available, if you prefer to test a building yourself. Most home inspectors and radon contractors perform this testing service and can be contacted for testing and to answer any number of related questions.
