Modeling of Pb and Po radionuclide emissions from local power plants in central Poland.

Due to the more volatile nature of Po in relation to Pb, an imbalance of activity concentrations in high temperature combustion processes can be observed, especially in fine particulates (diameter < 0.1, 0.2 and 0.5 μm). In the atmosphere and in the soil around coal-fired power plants, Pb and Po concentrations are a combination of activities from natural and anthropogenic sources. In this study only portions of Po and Pb radionuclides resulting from energy production activities were analyzed. Due to the high mobility of fine particles, a surface area of 172 km × 140 km in central Poland was chosen for simulation. For validation of the modeling approach, three grid versions were applied: 1 km, 2 km and 4 km. Simulated results confirmed experimental-computational values of an excess of both radionuclides in the atmosphere in 2017 in the city of Lodz. Different aerosol fractions, seasons and various grids in the selected area were subjected to 36 individual simulations. The Po activity concentrations measured in winter and summer 2017 were 42.5 and 8.99 μBq m, respectively. Simulated and measured values of artificial Po and Pb activities are well correlated.