Radionuclide Type
Time Period
Display Options
Contamination Levels (kBq/m²)
Region Information
Understanding Radiation Units
Becquerel (Bq): Measures radioactivity - one decay per second. The map shows kilobecquerels per square meter (kBq/m²), indicating contamination density.
Sievert (Sv): Measures biological effects of radiation. Often shown in millisieverts (mSv) - 1/1000th of a sievert.
Gray (Gy): Measures absorbed radiation dose - 1 joule of energy per kilogram of matter.
Contamination and Health Impacts
Areas with different contamination levels have different potential health impacts:
Greater than 1,000 kBq/m² (Red): Mandatory evacuation zones. Could give additional dose of ~10 mSv/year initially.
555 kBq/m² (Orange): One criterion for mandatory resettlement in 1986. Additional dose of about 5 mSv/year initially.
37 kBq/m² (Yellow): Areas of strict radiation control. Comparable to an additional ~0.5 mSv/year.
Less than 10 kBq/m² (Green/Blue): Low contamination level. Additional radiation close to normal background variations.
Decay Over Time
Cesium-137 has a half-life of ~30 years, meaning contamination levels today are about half what they were in 1986.
Iodine-131 has a half-life of 8 days, so it was a concern only in the immediate aftermath.
Strontium-90 has a half-life of ~29 years and tends to concentrate in bones and teeth.
Source: Data compiled from OECD Nuclear Energy Agency, World Health Organization, and International Atomic Energy Agency reports.
Map of pollution
