Thematic investigations produced detailed information about the key sources of radiation exposure.

The annual environmental radiation surveillance programme gives an overall picture of the levels of radiation in Finland. However, it cannot be used for comprehensive assessment of the safety of the environment: it does not give enough information on the exposure of special groups of people or the variation of radioactive substance levels and, consequently, variation of the exposure. The results of the surveillance programme are supplemented with thematic investigations. They produce more detailed, up-to-date information on the most important radiation exposure sources for Finns.