Sources of radiation

People are constantly exposed to natural radiation (radiation background). The radiation background includes cosmic radiation, most of which is absorbed by the atmosphere. Thus, the background acts more on people living in the highlands, or flying in an airplane. Radioactive elements, especially radon gas, are found in many rocks or minerals. These elements fall into various substances, including food and building materials. Radon exposure is usually 2/3 of the total dose of natural radiation.

People are also exposed to radiation from artificial sources, including nuclear weapons (for example, during tests) and various medical studies and treatments. Of natural and artificial sources, the average person gets about 3-4 mSv / year.

The average dose of ionizing radiation per year (USA)

A source	Dose (mSv)
Natural sources
Radon gas	2.00
Other terrestrial sources	0.28
Cosmic radiation	0.27
Natural internal radioactive elements	0.39
Total	2.94
Artificial sources
Diagnostic X-ray examination (for the average person)	0.39
Nuclear medicine	0.14
Consumer goods	0.10
Precipitation from nuclear weapon tests	<0.01
Nuclear industry	<0.01
Total	0.63
Total annual radiation	3.6
Other sources of radiation
Flight	0,005 per flight hour
Radiography of the tooth	0.09
Chest X-ray	0.10
Radiography with barium enema	8.75

There are cases of radiation leakage at nuclear power plants, for example, on the Three-Mile Island in Pennsylvania in 1979 and in Chernobyl in Ukraine in 1986. The release on the Three-Mile Island was minimal; people who lived within 1.6 km of the plant received only about 0.08 mSv. However, people living near the Chernobyl nuclear power plant received a dose of approximately 430 mSv. More than 30 people died, more people were infected, and radiation reached other parts of Europe, Asia and the United States. As a result, in addition to Chernobyl, radiation from reactors in the first 40 years of using nuclear energy resulted in 35 serious emissions with 10 deaths, none of which was associated with commercial power plants. Other significant events include the bombing of nuclear bombs in Japan in August 1945, which killed more than 100,000 people directly from the explosion and hundreds of thousands more from radiation sickness and other related injuries.

The possibility of using radiation exposure by terrorists seriously worries the public of all countries of the world. Possible scenarios of terrorist acts range from limited dispersal of radioactive substances without explosion to dispersal by conventional explosives ("dirty bombs") and attempts to capture and detonate nuclear reactors or nuclear weapons.

[1], [2]