The relevance of the presented research is related to the objective need for organizational improvement of radiation and radioecological monitoring in Ukraine under a full-scale war that began in February 2022. This is due to the increased risks of radioecological accidents, the threat of changes in the radiation situation, and the release of radionuclides into the air as a result of constant shelling of the territories near Nuclear Power Plants (NNPs) by Russian missiles and drones.

The study purpose is to provide a comprehensive radioecological assessment of the radiation state of atmospheric air and atmospheric fallout in the Nikolaev city and the Nikolaev region, as well as to develop, based on this assessment, proposals for optimizing radioecological monitoring of atmospheric air in Ukraine during military operations. The research methods were an analysis of the current system of radiation monitoring of atmospheric air in Ukraine, analysis of cases of recording changes in the radionuclide composition of atmospheric air due to the movement of the radioactive cloud, results of own observations of the effective dose rate and radiometry of atmospheric deposition samples.

The article presents research materials on the radioactive state of the atmospheric air, the content of radionuclides in atmospheric deposition in the city of Mykolaiv in 2023, and a comparative analysis with the indicators of previous years and in the settlements of the Mykolaiv region. To fully assess the effectiveness and efficiency of the current system of radioecological monitoring of atmospheric air, the results of radiometry of atmospheric air samples in the Mykolaiv region during the movement of the radioactive cloud with ruthenium-106 in autumn 2017 are presented. The scientific novelty is to expand the understanding of the tasks of radioecological monitoring of atmospheric air during military operations. The practical significance of the presented results is to obtain field research data for dosimetry of the population of Mykolaiv and Mykolaiv region during military operations of the Russian Federation, for cartographic modelling of the current formation of individual and collective external dose of the population in certain areas.