It does.
Natural sources of radiation in the human body
The main source of radioactivity in the body is the presence of certain trace radioactive elements, such as 14C and 40K.
Radioactive gas decay products of the uranium and thorium systems, i.e., radon gas and thorium shot gas, also contribute significantly to radioactivity in the human body.
As the earth's soil and water contain small amounts of radioactive substances, some of them are transferred to the human body through the cycle of drinking water and food chain, producing irradiation of the human body.
Other radioactivity in the human body is 226Ra, 228Ra and 14C, but in very small amounts.
Ionizing radiation is a general term for radiation that can cause material ionization, and there are many types of it, generally divided into two categories: high-energy particle beams and high-frequency electromagnetic waves. Energetic particle beams produced by the fission of heavy atomic nuclei, such as alpha rays, beta rays and neutron beams. High-frequency electromagnetic waves generated by the electron energy level jump, such as γ-rays and X-rays.
Ionizing radiation comes from a wide range of sources, mainly from rocks, soil, radioactive gases (e.g. radon gas) and other radioactive substances in nature, as well as from natural radionuclides in food and cosmic rays (e.g. X-rays, γ-rays). These several sources of radiation constitute the natural radiation of the human living environment.
Extended Information
There are also many sources of ionizing radiation in the living environment. Overall radiation levels can be higher in certain geologically specialized areas, such as human settlements near uranium mines; in terms of home furnishings, many building materials are also radioactive, such as marble.
Relative to the fixed environment, people in the mobile environment will also encounter ionizing radiation. For example, when traveling by plane, as the height of the plane increases, the dose of radiation from cosmic rays to the human body will also increase.
Baidu Encyclopedia - Sources of Radiation
People's Daily Online - Sources of Ionizing Radiation Around Us: Radiation is not scary, there is no common sense to be "anxious"
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