Table 16.6 - Worldwide annual average effective dose to adults from natural sources of ionising radiation
Source: UNSCEAR, 1993
Component of exposure | Annual effective dose (mSv) | |
---|---|---|
In areas of normal background | In areas of elevated exposures | |
Cosmic rays | 0.38 | 2.0 |
Cosmogenic radionuclides | 0.01 | 0.01 |
Terrestrial radiation: external exposure | 0.46 | 4.3 |
Terrestrial radiation: internal exposure (excluding radon) | 0.23 | 0.6 |
Terrestrial radiation: internal exposure from radon and its decay products: | ||
inhalation of Rn-222 | 1.2 | 10 |
inhalation of Rn-220 | 0.07 | 0.1 |
ingestion of Rn-222 | 0.005 | 0.1 |
Total | 2.4 | |
Note: Other sources not included in the worldwide averages include: the increase in cosmic radiation exposure during air travel, the exposure of radiological workers, exposure due to the Chernobyl accident and fall-out from nuclear weapons testing. Radiation doses are expressed in sieverts (Sv), which are a measure of the amount of energy absorbed by unit mass of tissue (see Effects and risks in the text).