Where is Radon Gas Found?
If you reside in the United States or Canada you should be aware that radon gas is found in the environment of all our regions. Radon is a noble gas that is formed by the decay of Uranium, a naturally occurring element found in the soil and in water. Although it is found in water, it will most likely affect us in its gaseous form in the air we breathe. Only two gaseous forms are found in elevated concentrations in our human environment. These are radon-222, and radon-220. Radon-220 is seen to be most prevalent in our human environments.
Radon is colorless and is not detected by our human senses. It is the heaviest known gas, and is about nine times heavier than Air (about 20% oxygen & 80% nitrogen). It is only one atom, instead of two like O2 and N2, and is able to go through common barriers such as clothing, paper, low-density plastic, wood siding, and most insulation products. It will also penetrate mortar, concrete blocks and sheet rock commonly used in building construction.
How is Radon produced and how does it get into our environment?
Radon is not manufactured commercially. It is a radioactive gas that is produced from the radioactive decay of uranium found in rocks, rocky formations and most soil. It is commonly found in ground water, building materials, or the ground itself. Usually the most severe inhalation problems occur in radon rich gaseous environments. It can be found in basement areas, caves, mines, enclosed spaces adjacent to closed areas exposed to the earth, or typically in public baths and spas.
What type of Levels of Radon are considered to be potentially harmful to humans , and at what concentrations?
The U.S. EPA and U.S. Public Heath Service, have given the estimate that at least 20,000 lung cancer deaths per year are caused by exposure to radon. It has become the second leading cause of lung cancer in the USA. About one-third of homes in the USA exhibit radon levels over 4pCi/L (4 picocuries/liter). This is amount is called the Action or Reference level of concern to inhabitants and home owners.
How can you make Accurate Measurements of Radon Levels in your home and other structures?
In general, electronic radon detectors work by detecting particles that are being thrown off by the natural decay of radon gas in the environment in close proximity to the detector. These particles are called “Alpha particles” and are counted as the result of being detected by a photo diode which is sensitive to these particles. The electronics in the device measures the alpha particle activity, and filters out the “noise” in the environment of the sensor.
If the detector is properly designed it will hold its calibration over a long period of time. Electronic measurement devices need to be calibrated when they are produced. Each detector is compared to a “standard” and is adjusted to measure within the accepted tolerance of the device to insure accurate measurements. Re-calibration will be required at some point, and the longer that period of the time the better, since re-calibration will involve an ongoing expense.
The electronic radon detector has an advantage of presenting an accurate readout value(s) over a period of time. It can be re-used and placed in all rooms of the home or business and give an accurate picture of radon levels throughout the year. Variation of radon levels are to be expected, due to climatic conditions and local variations in temperature, dust, airflow and moisture levels. Evaluation of radon levels should be averaged over many measurements and throughout the year.
The lowest cost test for radon in the home can be performed by a single use test device. These devices need to be in place for some time to obtain a useful radon reading. Unfortunately they are useful only in one certain area such as a room or basement, and they need to be physically mailed to a laboratory for analysis of the radon levels that they measured. They are a “one-time” measurement solution, and are not costly, ($25 or less) but to measure an entire building accurately, it might mean obtaining multiple detector strips and placing them throughout your home or office.