In contrast, the contribution from anthropogenic sources of radiation is usually much smaller, unless considering serious nuclear or radiation accidents, which occur very rarely.
The report is based on an extensive study of radiation exposure covering the period from 2007 to 2022 and includes an analysis of scientific publications.
According to the committee, the average global annual effective dose of exposure from natural sources is approximately 3.0 millisieverts. The largest contribution to this value comes from the inhalation of radon and its decay products—about 1.8 millisieverts per year. This is followed by the intake of radionuclides from food and water, as well as external exposure from radionuclides in the Earth's crust and cosmic radiation.
The new figure exceeds the previous estimate published in 2008, which was 2.4 millisieverts. Representatives of UNSCEAR note that the increase is related to improved access to data and methodology, rather than a real rise in radiation levels in the environment.
The report also emphasizes that the impact of anthropogenic sources—including medical, scientific, industrial, and household use of radiation technologies—under normal conditions amounts to only a few microsieverts per year.
For populations living near nuclear power plants, radiation levels remain low and typically do not exceed several tens of microsieverts per year. It is also noted that radiation exposure in areas of former nuclear tests has significantly decreased. Although radiation levels were high after the tests, currently at the sites in New Mexico, the Marshall Islands, Mururoa, Fangataufa, and Semipalatinsk, annual doses are generally much lower than the natural background.
Radiation levels associated with the Chernobyl and Fukushima accidents continue to decline due to natural processes, radioactive decay, and decontamination measures. Currently, annual doses in the vicinity of Chernobyl range from tens of microsieverts to several millisieverts, while in non-evacuated settlements around Fukushima, they range from a few microsieverts to about 0.3 mSv.
The UNSCEAR report is intended to provide governments and international organizations with relevant scientific data to assist in the development of effective policies in radiation safety and public health protection.
