During May 2020, the average monthly results of the determination of the exposure dose rate (EDR) at the monitoring points of the radiometric network of the National Hydrometeorological Service (NHMS) in different regions of Ukraine (outside the exclusion zone of the Chornobyl NPP) ranged from 62 nSv/h (M Kupiansk) to 159 nSv/h (M Korosten'), the minimum and maximum indicators of EDR, the variation of which for each monitoring point was mainly due to measuring errors, was recorded in M Korosten' (44nSv/h) and M Korosten (175 nSv/h) respectively.
In general, the overall radiation situation in Ukraine was steady and depended on the distribution of natural radionuclides in the upper layers of the earth.
The impact of aerosol emissions of NPP on the level of radioactive contamination of atmospheric air was disappearing small.
Doses of additional irradiation of the population of Ukraine as a result of the operation of the NPP were significantly lower than the permissible levels determined by the Radiation Safety Standards of Ukraine (RSSU).
The general distribution of the averaged per month of the EDR indicators on the radiometric network of the NHMS of Ukraine is presented in Fig.1. These indicators are ranged from 62 to 127 nSv/h on more than 90 % of Ukraine's territory. The highest values of EDR were observed on the territory that was subjected to significant radioactive contamination as a result of the Chernobyl accident, and on the observation points of the radiometric network of NHMS M Korosten' 159 nSv/h, and on M Chornobyl-174nSv/ h.
The table shows the average of the EDR values per month in all regional centres of Ukraine, the city of Kyiv and the town of Chernobyl.
The results of the measurements show that in May there was no movement of air masses across Ukraine, which would be contaminated with radioactive substances of technogenic origin and capable of increasing the level of natural radiation background.