The main ways of radiation risks assessment are considered: linear threshold-free model and practical threshold model. New approaches to selection of radiation risk assessment threshold based on comparison of man-made exposure doses with lifetime exposure doses from natural radiation sources are proposed. The threshold of risk assessment for exposure to radon daughter products equal to 30 Bq/m3 has been proposed. Using both threshold-free and threshold models the estimates of radiation risk for the population of Sverdlovsk region exposed to natural and anthropogenic sources were made. It is shown that the contribution of technogenic training is much lower than that of permanent radiation factors - radon and medical diagnostic irradiation.

It is shown that the optimal parameters for comparing the consequences of exposure of the population to different radiation sources are the expected frequency of radiation-induced cancer morbidity (radiation risk), as well as the loss of life expectancy. A methodology has been developed for a comprehensive assessment of both these parameters for the main sources of radiation impact on the population - radon and its daughter products, medical diagnostic X-ray procedures, consequences of radiation accidents in industry using any multiplicative and additive models of radiation risk extrapolation.