To measure radiation levels at any given time, a Geiger counter is used. A Geiger counter contains a special gas-filled tube that separates two electrodes. When radiation passes through the tube, it interacts with the gas, causing an electrical pulse that can be measured on a meter or by audible clicks. The number of pulses in a given time is a measure of the intensity of radiation. The Health Effects of Radiation Radiation is one of the most widely studied of all natural phenomena.
Scientists understand the health effects of high levels of radiation.
However, the effects of low levels of radiation are more difficult to determine because the major effect is a very slight increase in cancer risk. But because so many other factors also increase the risk of cancer, it is difficult to know which is the cause in many cases. Radiation can chemically change living cells. However, cell transformation does not necessarily cause noticeable health effects. If the radiation dose is low, or a person receives it over a long period of time, the body can usually repair or replace the damaged cells without any detectable health effects.