Аннотация
The article provides summarized results on the assessment of levels and nature of radioactive contamination of the air environment with naturally occurring and artificial radionuclides (NRN and ARR) in the territory of the Republic of Kazakhstan for the typical landscape unit – a steppe zone. A technique of the theoretical assessment of ARN activity concentrations in the air is applied. It was found that the content of 40K in the air varies from 6.5×10−6 to 9.5×10−5 Bq/m3, 226Ra –2.5×10−6 to 5.0×10−5 Bq/m3, 7Be – 9.0×10−4 to 4.5×10−3 Bq/m3, 210Pb – 1.0×10−4 to 8.5×10−4 Bq/m3, 239+240Pu – <1.0×10−7 to 7.3×10−7 Bq/m3. Results of the theoretical assessment of showed that estimated values of 232Th volumetric activity reach 1.8×10−6 Bq/m3, 241Am – 1.1×10−8 Bq/m3, 137Cs – 1.4×10−6 Bq/m3, 90Sr – 2.0×10−7. Data obtained for radionuclides background concentrations in the air is within ranges of values of international monitoring observations and can subsequently be used as basic indices for assessing variation in the quality of the air environment.