Effect of changes in the fuel type of thermal power plants on the spatial distribution and levels of PAH pollution in the Vorkuta agglomeration beyond the Arctic Circle

Abstract

The paper is a study of the composition of 15 polycyclic aromatic hydrocarbons (PAHs) in the snow cover of Vorkuta (Komi Republic) in the impact zone of the fuel and energy complex in 2017 and 2023. We have identified high aerotechnogenic pollution of the Vorkuta city and adjacent territories with PAHs during heating with fuel oil and coal, with a mean concentration of 301.6 ng/L (meltwater plus particles) and spatial distribution of 85.2 μg/m2. There is a significant decrease in PAH levels when the fuel for thermal power plants has been changed to natural gas, with a mean concentration of 26.1 ng/L (meltwater plus particulates) and spatial distribution of 4.9 μg/m2. The deposition areas of different PAH fractions are identified in the impact zones of Thermal Power Plants 1 and 2, the Central Boiler House and the urbanised areas of the Vorkuta agglomeration. 2-4-ring PAHs dominate in the emissions, accounting for 92–100 % of the sum of PAHs from coal/oil combustion and 66–93 % from natural gas combustion. The indicator ratios of PAHs in the snow cover of Vorkuta in both 2017 and 2023 indicate their predominantly pyrogenic genesis. The environmental risk coefficients of PAHs in the snow cover and their change from 2017 to 2023 are calculated. TEQ changed from 2.1 ng/L (mean) in the 2017 season to 1.7 ng/L (mean) in the 2023 season. The risk quotients have been reduced from moderate risk to low risk. Reconstruction of thermal power plants when replaced by more environmentally friendly fuel (natural gas) reduces the amount of atmospheric emissions of organic pollutants.