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Correlation between precipitation and area dose rate

The animation shows the correlation between the precipitation and area dose rate. When it is raining, the air is quasi purified, i.e. particles floating in the air (aerosols) are washed out and thus reach the earth’s surface. These particles carry radioactive isotopes (mainly radon progenies). Especially after a long drought, this leads to a clear increase in the area dose rate at the earth’s surface.

In the course of the measurement shown which was performed at the reference measuring site for environmental radiation in Braunschweig it could be seen that after a heavy rain shower with 14 mm in 15 min. (blue bar) the area dose rate (red bar) increases from 106 nSv/h to 196 nSv/h.