UNIS/OUS/453
12 February 2026
VIENNA, 12 February (UN Information Service) — Natural sources of ionizing radiation—such as radon, thoron, cosmic rays and terrestrial radionuclides—remain by far the most significant contributors to public exposure worldwide according to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in a new report published today. Exposure of the public to human-made radiation sources is generally much lower than exposure from natural sources, except in rare cases such as major radiological accidents.
The findings are published in UNSCEAR’s latest scientific annex, “Evaluation of public exposure to ionizing radiation”, providing the most comprehensive global assessment to date of radiation doses received by the general public from natural and human made sources. It draws on data collected through the UNSCEAR Global Survey on Public Exposure and an extensive review of published scientific literature covering the period 2007 to 2022.
The Committee estimates that the worldwide average annual effective dose from natural sources is approximately 3.0 millisieverts (mSv). The largest contributor is inhalation of radon, thoron and their decay products (1.8 mSv), followed by ingestion of naturally occurring radionuclides (0.5 mSv), and external exposure from terrestrial radionuclides (0.4 mSv) and cosmic radiation (0.3 mSv). The increase from the previously reported global average of 2.4 mSv (UNSCEAR 2008) reflects improved data availability and methodological refinements, rather than an actual rise in radiation levels.
“This new evaluation provides a clearer and more globally representative picture of the radiation doses that people receive in their daily lives,” said Dr. Sarah Baatout, Chair of UNSCEAR. “Thanks to better data and improved science, we can more accurately assess public exposure and support national and international efforts to ensure continued protection of public health.”
Key findings of the new evaluation
• Natural background radiation remains the dominant source of public exposure.
Even with improved estimates, natural radiation continues to account for the vast majority of doses received by the general public.
• Human made sources generally contribute only a small fraction of total public exposure.
Outside of rare major accidents, exposures from medical, industrial, research and consumer applications of radiation technologies are typically in the range of only a few microsieverts per year.
• Nuclear power plant discharges result in very low doses to the public.
Annual doses to members of the public living around nuclear power production facilities generally do not exceed a few tens of microsieverts. The collective effective dose per unit electricity generated is estimated at 0.4 person-Sv/(GW·a).
• Exposures from past nuclear weapons testing sites have dramatically decreased.
While exposures immediately after historical tests were significant, present day doses at historical nuclear weapons test sites in New Mexico, the Marshall Islands, Mururoa and Fangataufa, and Semipalatinsk are generally well below natural background levels.
• Public exposures related to the Chornobyl and Fukushima Daiichi accidents continue to decline.
Environmental radionuclide levels and resulting public doses have fallen steadily due to radioactive decay, environmental processes and remediation. Current annual doses near Chornobyl range from tens of microsieverts to a few millisieverts, and from a few microsieverts up to about 0.3 mSv in non evacuated municipalities near Fukushima Daiichi.
The full report is available on the UNSCEAR website:
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The mandate of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), established in 1955, is to undertake broad reviews of the sources of ionizing radiation and the effects on human health and the environment. Its assessments provide a scientific foundation for United Nations agencies and governments to formulate standards and programmes for protection against ionizing radiation. It does not deal with or assess nuclear safety or emergency planning issues. The secretariat in Vienna, which is functionally linked to the UN Environment Programme, organizes the annual sessions and manages the preparation of documents for the Committee's scrutiny.
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For information contact:
UNSCEAR secretariat
Telephone: (+43-1) 26060 4122
Email: unscear[at]un.org
www.unscear.org
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