In contrast, anthropogenic sources of radiation, except for major nuclear accidents, contribute a negligible amount. The report is based on an analysis of data from a global study on population exposure and scientific literature from 2007 to 2022.
The average annual dose of exposure from natural sources is about 3.0 millisieverts, according to the committee's calculations. The most significant impact comes from inhalation of radon and thoron, as well as their decay products, which accounts for approximately 1.8 millisieverts per year. The second most significant cause of exposure is the intake of radionuclides through food and water, as well as external exposure from radionuclides in the Earth's crust and cosmic radiation.
This new estimate exceeds the previous one presented in 2008, which was 2.4 millisieverts. However, UNSCEAR indicates that this increase is related to improvements in data collection and analysis methods, rather than an increase in environmental background radiation.
The study also highlights that the contribution of anthropogenic sources, including medical, scientific, and industrial applications of radiation technologies, under normal operating conditions, amounts to only a few microsieverts per year.
Exposure doses for populations living near nuclear power plants also remain extremely low—typically not exceeding a few tens of microsieverts per year.
Furthermore, radiation levels in areas where nuclear tests were conducted have significantly decreased. While exposure levels were high immediately after the tests, current exposure doses at sites in New Mexico, the Marshall Islands, Mururoa, Fangataufa, and Semipalatinsk are generally below natural background levels.
After the accidents at the Chernobyl and Fukushima nuclear power plants, exposure levels continue to decline due to radioactive decay and decontamination measures. Currently, annual doses around Chernobyl range from tens of microsieverts to several millisieverts, while in non-evacuated areas near Fukushima, they range from a few microsieverts to about 0.3 millisieverts.
The aim of the UNSCEAR report is to provide updated scientific data that can assist governments and international organizations in developing effective policies for radiation protection and public health.
