Radon, a radioactive gas, forms naturally from the decay of radium or uranium in the soil under a house. Radon gas can move up from under the house and enter the house through any holes or cracks in the foundation. Once in the house, the gas can be trapped and rise to dangerous levels.
Only in the mid 1980's did scientists begin to understand how dangerous radon poisoning is. Radon cannot be noticed by human senses — it is colorless, tasteless, and odorless — so it is difficult to know if you are being poisoned. Furthermore, radon is estimated to cause around 21,000 lung cancer deaths per year in the United States alone.
The radon level in a specific home depends on many different factors, including the uranium content of the soil, geological formations under the house, and the construction of the house, making each home highly individual with regards to its radon levels. Radon testing is the only way to determine the level of radon in a home, as even homes next door to each other can have drastically different levels of the gas.
The level of radon present in the air is measured in picoCuries per liter of air, or pCi/l. The lower the level of radon, the safer the air is; four pCi/l is thought to be the same as smoking 10 cigarettes per day. Tests can be purchased at most hardware stores and easily performed by homeowners. A short-term test is the most common, as you can get almost immediate results. Long-term tests are also available, but can take a full year to complete.
Before performing a short-term test for radon, all windows and doors in the house should be closed for no less than 12 hours, with no ventilation systems being used. Fresh air entering the house could skew the results of the radon test. The test should always be conducted on the lowest living area of the house. The radar detectors should be kept away from drafts and out of direct sunlight. They should be used in rooms other than the laundry room, kitchen, and bathroom.
To conduct a radon test, simply remove the caps from the radon detectors and set them on a flat surface in the room to be tested. Radon detectors should be at least two feet (61 cm) off the floor, two feet (61 cm) away from an outside wall, and six inches (15 cm) away from each other. Leave the detectors undisturbed for four full days (96 hours), and then replace the caps.
After replacing the caps, record the date and exact time that the test ended on the data card. The radon detectors, data card, and a payment for the lab free should then be sent — within 24 hours of the test's end time — to the lab designated. Some kits include the lab fee in the price of the radon test kit.
If a home is found to have elevated levels of radon, the radon needs to be vented from the ground, away from the house. An approved radon-mitigation contractor should do the work, which involves a pipe and fan system to vent the gas from under the floor slab to over the roof of the house. This is not a project for a do-it-yourselfer.
Written by Bronwyn Harris
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