Abstract—: Mineralogical–geochemical properties of snow were studied in the activity areas of the mining and ore-processing companies Severonikel in Monchegorsk, Karelsky Okatysh in Kostomuksha, and Sibay Mining and Processing Company in Sibay. The mineralogical and chemical compositions of the aerosols corresponds to the metallogeny of the study areas and the ore specialization of enterprises. The solid aerosols consist of the rock-forming and accessory minerals and artificial anthropogenic materials: slag particles and Ni–Fe–Co ± Cu aggregates. The presence of microplastics in the composition of solid aerosols was established within residential areas and on the territory of the Kostomuksha State Reserve, which is under the influence of transboundary transport. Concentrations of metals (Fe, Mn, Ni, Cu, Zn, Cd, and Pb) in the aerosols and snowmelt water are much higher than the average concentrations of these metals in the Earth’s crust and natural waters. The pH of the snowmelt water is determined by the landscape–geochemical conditions and determines the solubility of metals: the minimum in the steppe landscapes of the Sibay area and the maximum in the Monchetundra (Monchegorsk test site). Within the latter, dissolved forms of chalcophiles and Ni predominate over the solid phase. Dust, metal, and ionic loads on the territory have been calculated. Retrospective analysis over the past 25 years has shown significant changes in the composition of aerosols within the Monchegorsk reference area due to the exclusion of the Talnakh ore dressing process from production. Among the studied emission sources of metals, the greatest contribution to the biogeochemical cycling is made by the Severonikel facilities.