NORM — or naturally occurring radioactive material — is found almost everywhere and the average person in the CIS is exposed to about 360 millirems of radiation from natural sources each year. A millirem — or 0.001 of a rem — is a measure of radiation exposure and more than 80 percent of this exposure level comes from background radiation sources. For example, consumer products contribute 10 millirem/year, while living or working in a brick building can add another 70 millirem/year. On the extreme, a person who smokes 1.5 packs of cigarettes each day increases his or her exposure by 8,000 millirem/year. A Geiger counter produces an audible click and blinks an LED each time it detects a radioactive particle. Typically, the counter clicks 10-20 times a minute due to normal background radiation (which is less than 80 millirem/hr) and — although the device is sensitive enough to measure background radiation — it is not suitable for measuring radon gas. Radon is a colorless, tasteless gas that also comes from uranium and is found in many rocks and soil, especially soil that has been contaminated with pollution. It's natural- ly found in the air we breathe, but is harmless because it is so diluted that we don't notice it. There are radon gas detectors that use an activated charcoal filter that are easy to use and more accurate.
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