Radiation

• Natural sources of radiation include cosmic radiation, gamma radiation prevailing at ground level, decay products of radon in the air and various radionuclides found naturally in food and drink.
• Artificial sources of radiation include medical X radiation, radioactive waste caused by testing nuclear weapons in the atmosphere and the emission of radioactive waste from the nuclear industry.

Ionising radiation

Ionising radiation is imperceptible and measuring the level of radiation is only possible using a special measuring device.

Radioactive substance emits ionising radiation creating ion-pairs in tissues meaning that some part of the molecules brake down into electrically charged particles. The spontaneous fissile ability of atomic nuclei is called radioactivity and the respective atomic nuclei are called radionuclides.

The released particles and gamma-quanta are capable of ionising the surrounding substance. That is why the flow of released particles and gamma-quanta is called ionising radiation.

Ionising radiation may be natural, for example, radioactive gas radon found in the ground emits alpha radiation. In processing X-ray images, however, artificially created X-rays are used.

For living tissues, the most dangerous radiation is ionising radiation because its qualities are most hazardous to human tissue, causing diseases such as cancer.

Radiation monitoring

In Estonia, information on the radioactivity levels in the environment is collected through the annual national radiation monitoring program. Every year, more than 250 collections of environmental samples are examined. The main focus is on the radionuclides emitted into the environment by human activity.

Estonia does not have any nuclear power plants, meaning that the main threat is pollution coming from outside the border. The general gammadose rate in the atmosphere is monitored in real-time in 10 monitoring stations across Estonia and the radioactivity of airborne particles in 3 filtering stations.

Approximately half of the radiation dose affecting the residents is caused by radioactive gas radon which is found in the earth’s crust. Radon occurs naturally upon the decay of uranium. Uranium can be found more or less everywhere in the earth’s crust Therefore radon can also be found everywhere. High level of radon found in soil is connected with the Dictyonema argillite crops (Northern Estonia) and the coverage of moraine rich in granite (Southern Estonia).