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Figure 13.4 – The natural barrier Earth gives us against solar radiation.
On average, a person living at sea level receives 300 μSv from cosmic
radiation – high-energy radiation from outer space reaching the earth’s surface. The
dose varies with latitude and altitude.
Air crew and airline passengers receive an additional dose from cosmic
radiation. The dose received depends on the frequency of flights and the routes flown.
3) Natural radioactivity in soils
Radioactive elements occur naturally in all rocks and soils and have been there
since the creation of the Earth. On average, a person receives 300 μSv every year
from the radiation emitted from this source.
4) Natural radioactivity in food (radiation in the human body)
Figure 13.5 – Sources of ionizing radiation
The natural radioactivity present in soil is transferred to crops and grazing
animals, thereby resulting in a radiation dose when these are eaten. Similarly,
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