Health Effects of Radiation:
5 Themes
Radiation Around Us

(i) Radiation around us

We are exposed to radiation in our daily lives without realizing it. In addition, there are natural radioactive materials contained in the human body and common foods.

Measurement results for ambient dose rates in major cities

Measurement results for ambient dose rates in major cities
Source:
Created based on Japan National Tourism Organization data
(https://www.jnto.go.jp/eq/eng/04_recovery.htm, as of December 2018)

The diagram above shows the ambient dose rate measurement results for major cities in Japan and other parts of the world.
This shows that radiation dose varies in different areas. This is mainly due to differences in the amount of ground radiation caused by soil and rock composition.

For more information about the ambient dose rate measurement results for major cities, see page 70 of Vol. 1, FY2017 edition
(available in Japanese only).

Natural radioactive materials in the human body and foods

As shown in the figure to the left, the human body and common foods contain radioactive materials. Potassium is an essential element for life, and because 0.01% of potassium is radioactive, most foods contain radioactive potassium. Radioactive potassium emits β-particles and γ-rays, causing internal exposure from food intake. The internal potassium concentration is held constant, so exposure doses from potassium in foods depend on individuals’ physiques and are considered unaffected by diet.

Natural radioactive materials in the human body and foods
Source:
Prepared based on “Research on Data about Living Environment Radiation (1983),” Nuclear Safety Research Association

or more information about natural radioactive materials, see page 70 of Vol. 1, FY2017 edition.

Health Effects of Radiation: 5 Themes