Physical and Chemical Characteristics of Different Aerosol Fractions in the Southern Baikal Region (Russia) During the Warm Season

The Baikal region, including areas with poor environmental conditions, has significant clean background zones. In summer of 2023, we analyzed physical and chemical parameters of aerosol particles with different size fractions at Irkutsk and Listvyanka monitoring stations. Reduced wildfires and minimal impact from fuel and energy industries allowed us to observe regional and transboundary pollution transport. A large data array indicated that, during the shift of cyclones from Mongolia to the south of the Baikal region, the concentrations of Na⁺, Ca²⁺, Mg²⁺, K⁺, and Cl⁻ ions increased at the Irkutsk station, dominated by NH₄⁺ and SO₄²⁻. The growth of the ionic concentrations at the Listvyanka station was observed in aerosol particles during the northwesterly transport. When air masses arrived from the southerly direction, the atmosphere was the cleanest. Analysis of 27 elements in aerosols revealed that Al, Fe, Mn, Cu, and Zn made the greatest contribution to air pollution at the Irkutsk station, while Fe, Al, Cu, Cr, Mn, and Ni – at the Listvyanka station. The dynamics of the investigated elements was mainly due to natural processes in the air under various synoptic situations and weather conditions in the region, although anthropogenic factor also affected the formation of aerosol composition wth certain directions of air mass transport.