This study is aimed at elucidating the fractional composition, volume and toxicity of dust that is deposited in the snow cover for the period of snow accumulation at different distances from coal mines and a coal-fired power station in the Kemerovo region (Russia). During the filtration process, fractions of 10–0.1 µm and less than 0.1 µm were isolated and weighed. Light microscopy was used to estimate the size of dust particles in the 10–0.1 µm fraction. We found that the total volume and fractional composition of dust has no significant trend to change in the research space. The dust contamination is associated mainly with PM₂ particles. Genotoxic tests on cell lines A549 and MRC-5 with different concentrations of dust showed high toxicity (including control points). Taking into account the fact that an increase in the concentration of PM leads to intensification in the toxicity of dust, we can determine that the territory within the studied boundaries is dangerous for the population. Our study is important for understanding the processes of formation, toxicity, transport and sedimentation in the snow cover from dust generated in the process of coal mining and the operation of a coal-fired power station.

Particulate matter (PM) <10 μm in size represents an extremely heterogeneous and variable group of objects that can penetrate the human respiratory tract. The present study aimed to isolate samples of coarse and ultrafine PM at some distance from polluting industries (1–1.5 km from the border of open-cast mines). PM was collected from snow samples which allowed the accumulation of a relatively large amount of ultrafine particles (UFPs) (50–60 mg) from five objects: three open-cast mines, coal power plants, and control territories. The chemical composition of PM was examined using absorption spectroscopy, luminescence spectroscopy, high-performance liquid chromatography, X-ray diffraction (XRD), and X-ray fluorescence (XRF) analyses of solid particle material samples. Toxicity was assessed in human MRC-5 lung fibroblasts after 6 h of in vitro exposure to PM samples. The absorption spectra of all the samples contained a wide non-elementary absorption band with a maximum of 270 nm. This band is usually associated with the absorption of dissolved organic matter (DOM). The X-ray fluorescence spectra of all the studied samples showed intense lines of calcium and potassium and less intense lines of silicon, sulfur, chlorine, and titanium. The proliferation of MRC-5 cells that were exposed to PM_0.1 samples was significantly (p < 0.01) lower than that of MRC-5 cells exposed to PM₁₀ at the same concentration, except for PM samples obtained from the control point. PM_0.1 samples—even those that were collected from control territories—showed increased genotoxicity (micronucleus, ‰) compared to PM₁₀. The study findings suggest that UFPs deserve special attention as a biological agent, distinct from larger PMs.