EngineerHub.orgBuild an annual radiation-exposure profile
Estimate natural background from radon, cosmic radiation, terrestrial gamma radiation and ingestion. Add medical exposure separately if desired.
Annual components
Annual dose profile
Background
Open a section to understand the model, equations and limitations.
UNSCEAR groups natural exposure into inhalation of radon and thoron progeny, cosmic radiation, external terrestrial gamma radiation and ingestion of naturally occurring radionuclides.
The latest UNSCEAR public-exposure assessment reports an approximate global average natural dose of 3.0 mSv/y, while the widely cited earlier estimate was 2.4 mSv/y. These are broad averages, not personal limits.
Indoor radon can vary by orders of magnitude. Cosmic dose changes with altitude, terrestrial dose with geology and building materials, and ingestion with local food and water.
Medical imaging is an intentional exposure and is not part of natural background. It is displayed separately because patients should not interpret a medically justified examination as an environmental exposure limit issue.
UNSCEAR currently estimates worldwide average exposure from natural sources at approximately 3 mSv/year, but individual values vary widely because radon, altitude, geology, buildings and diet differ. This average is a comparison benchmark, not a legal limit.
The 1 mSv/year public dose limit applies to additional exposure from regulated planned practices. It does not cap natural background or justified medical exposure.
Frequently Asked Questions
Practical questions about interpretation and use.
Use the representative presets as context only. A measured radon concentration and measured local gamma dose rate will normally improve the estimate most.
Medical exposure is not natural background. The optional field is shown separately so users can compare total personal exposure without confusing the categories.
Radon, geology, altitude, diet, building materials and medical use vary greatly between individuals and locations.
No. It is an approximate current global average from natural sources, not a regulatory limit for an individual.