The article presents the results of continuous automatic monitoring of atmospheric transport of pollutants in the source area of the Angara river (South Baikal) at the “Listvyanka” atmospheric monitoring station in 2019-2020. The temporal variability of the concentrations of oxides of sulfur, nitrogen, and mercury in the atmosphere of the сentral ecological zone of the lake Baikal is analyzed with high resolution from minutes to days. The use of automatic high-resolution gas analyzers for atmospheric impurities and meteorological parameters allows real-time monitoring of the flow of atmospheric pollution into the сentral ecological zone of South Baikal. Depending on the meteorological and synoptic conditions, observations demonstrate a high variability in the concentrations of anthropogenic impurities in the atmosphere over South Baikal. It is shown that the most severe atmospheric pollution occurs during the transfer of air masses from the north-northwest in winter. When transported from the South Baikal, atmospheric pollution is minimal. The temporal variability of the concentrations of the studied impurities occurs synchronously, which indicates their common source of origin – the combustion of fossil fuel. The highest time fluctuations are determined for the concentrations of sulfur and nitrogen oxides, the fluctuations in mercury concentrations are less significant. The average (median) and maximum (one-time) concentrations of sulfur oxides at “Listvyanka” station are given, depending on the prevailing wind directions. Direct trajectories of air mass transfer from the source cities of the Irkutsk region (Irkutsk, Angarsk, Shelekhov) are presented. At the time of the increase in the concentration of gas impurities at the “Listvyanka” station, pollution was transferred from the industrial complexes of the Baikal region. In the conclusion of the article, it is concluded that there are two main mechanisms of atmospheric pollution in the central ecological zone of Lake Baikal: direct transfer of individual weakly scattered plumes of separate regional thermal power plants with jet air currents at the upper boundary of the night boundary layers of the atmosphere (from 200 to 500 m above ground level); large-scale northwestern transport of mixed emissions from many regional and remote sources under the influence of synoptic-scale processes. Small settlements located on the coast, due to small volumes of emissions, do not make a significant contribution to the pollution of the lake's atmosphere. The work was supported by the Ministry of Science and Higher Education of the Russian Federation (grant No. 075-15-2020-787 for implementation of large scientific project «Fundamentals, methods and technologies for digital monitoring and forecasting of the environmental situation on the Baikal natural territory».

Khodzher Tamara Victorovna, Doctor of Sciences (Geography), Professor, Head of Laboratory of Hydrochemistry and Atmosphere Chemistry, Limnological Institute SB RAS, 3, Ulan-Batorskaya st., Irkutsk, 664003, Russian Federation, e-mail: khodzher@lin.irk.ru 

Obolkin Vladimir Arcadievich, Candidate of Sciences (Geography), Senior Research Scientist, Limnological Institute SB RAS, 3, Ulan-Batorskaya st., Irkutsk, 664003, Russian Federation, e-mail: obolkin@lin.irk.ru 

Molozhnikova Yelena Vladimirovna, Candidate of Sciences (Technical), Senior Research Scientist, Limnological Institute SB RAS, 3, Ulan-Batorskaya st., Irkutsk, 664003, Russian Federation, e-mail: yelena@lin.irk.ru 

Shikhovtsev Maxim Yurievich, Engineer, Limnological Institute SB RAS, 3, Ulan-Batorskaya st., Irkutsk, 664003, Russian Federation, e-mail: max97Irk@lin.irk.ru

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