Methodology for assessment of exposure to environmental factors in application to epidemiological studies: assessment of exposure to natural ionizing radiation.

This paper reviews the recent progress of passive measurement methods of gamma radiation and radon. Relatively cheap and reliable dosimeters are now available. Results from national and world-wide surveys of natural radiation in bedrock and soils and indoor radon concentrations exist. These can be used to more precisely indicate areas with enhanced exposure to gamma radiation, indoor radon levels and radium and radon in household water. Besides direct measurements of the radiation intensity, additional information (e.g., history of residence, house ventilation habits) is required to reconstruct historical exposure levels for epidemiological investigations. The availability and correctness of this information may influence the validity of exposure estimates.