Navigation and service

Ionising radiation

Environmental Radioactivity - Medicine - Occupational Radiation Protection - Nuclear Hazards Defence

Ionisierende Strahlung

What is the level of natural radiation exposure in Germany?

  • The total natural radiation exposure in Germany, respectively the annual effective dose for members of the public is on average 2.1 millisievert.
  • Depending on the place of residence, dietary and life habits, it sometimes adds up from 1 millisievert to 10 millisievert.

Glossary EntryRadiation exposure

Exposure denotes the totality of all environmental impacts (biological, chemical or physical) to which objects or living organisms, especially humans, are exposed. If the impact is radiation, it is called radiation exposure.

In the case of humans, a distinction is made between

  • whole-body exposure, where the whole body is exposed to radiation, and
  • partial-body exposure, where individual organs, tissues or body parts are exposed to radiation.

In the case of external radiation exposure, the radiation source is outside the body.

The term internal radiation exposure is used if radionuclides are incorporated through breathing (inhalation) through food or drinking water (ingestion) or through open wounds and hence represent a radiation source inside the body.

Glossary Entry Dose

Dose is a measure for radiation effects. See also absorbed dose, organ dose, effective dose.

Glossary EntrySievert

SI unit of the dose equivalent and of the effective dose is named Sievert (Sv), 1 Sievert = 1,000 Millisievert (mSv) = 1,000,000 Mikrosievert (µSv).

From the beginning, humankind lives in a radiating environment owing to the natural sources of radiation.

Thus natural radiation exposure leads to an annual effective dose for a member ot the public in Germany of 2.1 millisievert on average. Depending on the place of residence, dietary and life habits, it sometimes adds up from 1 millisievert to 10 millisievert.

Incorporation of natural radioactive substances by inhalation or ingestion

Natural radiation exposure is composed of a dominant internal and an external component.

Via air and nutrition, human beings have always absorbed natural radioactive substances:

  • The inhalation of the radioactive noble gas radon and its decay products results in an average annual dose of 1.1 millisievert.
  • Natural radionuclides of the radioactive decay chains of thorium and uranium as well as potassium-40 are taken up via food, which adds on average 0.3 millisievert annually.

External exposure by cosmic radiation and terrestrial radiation

External radiation exposure represents about one third of the total natural radiation exposure - resulting in a annual dose of approximately 0.7 millisievert. About half of it is due to cosmic radiation, which reaches the earth from the deep space and mainly consists of high-energy particles. On its way through the atmosphere cosmic radiation is partially absorbed on its way to the ground owing to nuclear reactions with the atomic nuclei of the air molecules. Therefore, its intensity depends on the altitude. It is lowest at sea level and increases with the altitude of a site. On the Zugspitze, Germany's highest mountain, it is four times higher than on the coast.

Terrestrial radiation is also part of external radiation exposure. It originates from natural radioactive substances existing in the soils and rock layers of the earth's crust in regional different concentrations.

Rocks and soils again are important raw materials for mineral building materials such as bricks and concrete. The radionuclides contained therein pass over to the building materials and thus also contribute to the external radiation exposure for people livin in buildings. On average, the terrestrial radiation adds up to an annual dose of 0.4 millisievert for members of the public, around 0.1 millisievert outdoor and 0.3 Millisievert indoor.

Man-made radiation exposure by medical and technical applications

Today, apart from natural radiation exposure, ionising radiation from medical and technical applications affects humankind as well. The mean annual effective dose of the so-called man-made radiation exposure is about 1.9 millisievert in Germany.

To the topic

Video (in German only)

State of 2017.05.08

How do you rate this article?

© Bundesamt für Strahlenschutz