Large-scale wildfires are essential sources of black carbon (BC) and brown carbon (BrC), affecting aerosol-induced radiative forcing. This study investigated the impact of two wildfire plumes (Plume 1 and 2) transported to Moscow on the optical properties of BC and BrC during August 2022. During the wildfires, the total light absorption at 370 nm (b(abs_370nm)) increased 2.3-3.4 times relative to background (17.30 +/- 13.98 Mm(-)(1)), and the BrC contribution to total absorption increased from 14 % to 42-48 %. BrC was further partitioned into primary (BrCPri) and secondary (BrCSec) components. Biomass burning accounted for similar to 83-90 % of BrCPri during the wildfires. The b(abs_370nm) of BrCPri increased 5.6 times in Plume 1 and 11.5 times in Plume 2, due to the higher prevalence of peat combustion in Plume 2. b(abs_370nm) of BrCSec increased 8.3-9.6 times, driven by aqueous-phase processing, as evidenced by strong correlations between aerosol liquid water content and b(abs_370nm) of BrCSec. Daytime b(abs_370nm) of BrCSec increased 7.6 times in Plume 1 but only 3.6 times in Plume 2, due to more extensive photobleaching, as indicated by negative correlations with oxidant concentrations and longer transport times. The radiative forcing of BrCPri relative to BC increased 1.8 times in Plume 1 and Plume 2. In contrast, this increase for BrCSec was 3.4 times in Plume 1 but only 2.3 times in Plume 2, due to differences in chemical processes, which may result in higher uncertainty in its radiative forcing. Future work should prioritize elucidating both the emissions and atmospheric processes to better quantify wildfire-derived BrC and its radiative forcing.

The accumulation levels and sources of potentially toxic elements (PTEs) were investigated in urban soils, road dust, and their PM10 fractions in Kerch, an industrial port city that hosts two abandoned dry tailings dumps from a former iron ore complex. The study aimed to characterize the geochemical signature of urban soils and road dust, with particular emphasis on the PM10 fraction as a key indicator of particulate-bound contamination; to quantify the contribution of anthropogenic sources to urban pollution; and to compare the results with data from other Crimean cities. PTEs contamination was evaluated using three complementary indices: the contamination factor (CF), concentration Clarke (CC) and enrichment factor (EF). The highest levels of soil contamination were observed in industrial zones and mid-rise residential areas, whereas road dust contamination was strongly influenced by proximity to tailing ponds and major traffic hubs. The PM10 fraction showed elevated PTEs accumulation, particularly in road dust. Overall, soil contamination ranged from low to moderate, while PM10 contamination in road dust ranged from moderate to high levels. Source apportionment using APCS/MLR revealed that tailings from the former iron ore complex are the primary source of As, Co, Fe, V, Mn, Be, and Ba in soils and road dust. Vehicular traffic contributes through two distinct sub-sources: brake wear (Sn, Sb, Cu, Mo) and tire wear (Cd, Pb, Zn). Active metallurgical industry releases Bi, Cs, Cd, W, and Pb to road dust and Sn, Bi, Ni, and W to soils. A terrigenous (natural) source controls Sr, Cr, and partially Cs and Mn concentrations, but with mixed contributions for some elements. PTEs in soils primarily originate from the resuspension of tailing pond dust, while road dust contamination reflects contributions from both resuspended soil material and vehicular emissions.

Moscow megacity is experiencing the largest net population growth in Russia and across Europe, resulting in significant climatic and hydrological changes of the small rivers. High-frequency (30-min) automatic streamflow and sediment monitoring with turbidity sensors was performed in 2019-2024 across the Setun River-the major tributary of the Moskva River, with a 190 km2 catchment area. It was also enhanced with 8 detailed records by the in-situ LISST-200x laser diffractometer, spanning 49 h from February to April 2024. The geospatial analyses of the catchment revealed up to 40 % distribution of impervious surface types, which determines a novel streamflow regime. Its main features are frequent short-term peak flow events, up to 29 per year, and a short flood wave catchment response to rainstorms. Downstream increase in residential area density and impervious surface area from upstream to downstream areas does not affect the relative contribution of various water sources, whereas a 3-4-fold increase in suspended sediment transport conditions along the river is registered. Short-lived increases in suspended particulate matter (SPM) concentration and grain sizes are characterized by hysteresis effects due to hydraulic sorting of suspended sediments along the river channel downstream of the local pollution sources. Finally, we developed a robust and novel methodological approach for forecasting suspended sediment concentrations from water level and flow, precipitation, and air temperature in a fluvial urban system by adopting 5 machine learning models with a resolution of 30 min to 1 day. The best results were demonstrated by the recurrent neural network LSTM for daily water turbidity values with a root-mean-square error of 10.8 NTU.

This study examines the contamination levels and sources of 32 metals and metalloids (MMs) in environmental compartments (roadside soil, road dust, and river suspended sediments) of a small urbanized river catchment located in Moscow megacity. MMs partitioning between particle size fractions (PM1000, PM1-10, and PM1) was analyzed by ICP-MS and ICP-AES methods. The pollution level of particle size fractions with MMs decreases in the following series: road dust > suspended sediments > soils. Absolute principal component analysis with multiple linear regression (PCA/APCS-MLR) shows that in both relatively coarse (PM1-10) and fine (PM1) fractions, traffic emissions are the primary contributors to pollution, whereas natural sources are dominant providers of chemical elements in bulk samples (PM1000). The predominance of fractions with a diameter over 10 mu m in all three studied compartments indicates that the mineral matrix of all compartments is formed predominantly by natural material. Across all compartments and their fractions, Sb, Cd, Zn, Mo, W, Sn, Cu, Pb, and Bi are consistently accumulated. PM1 and PM1-10 particles of road dust and suspended sediments also absorb Ni and Cr, suspended sediments retain Mn and As, and soils additionally accumulate As. Anthropogenic influence is more pronounced in PM1 and PM1-10 particles compared to bulk samples due to a large impact of industrial sources, traffic, construction activities, and waste storage. Polluted soils are an additional source of MMs to PM1 and PM1-10 of road dust and PM1-10 of suspended sediments, and road dust acts as a source of MMs to PM1-10 of soils.

Catchment erosion, channel erosion and sediment transport are connected processes within fluvial system forming a sediment cascade. Studies related to connectivity between a specific source and its multiple sinks within catchment, and rivers, and their multiple impacts have expanded in scope and sophistication during the last two decades, and were recently broadly presented at numerous international conferences and workshops. The International conference on transboundary catchment erosion and pollution problems was held in Belgrade, Serbia, in July 2023. The outcome of this conference as comprehensive literature review on the topic initiated this review which is aimed at classification the functional scheme of soil erosion, channel processes and sediment transport, and their impacts which include natural hazards, river pollution and hydrogeochemistry, catchment management, and hazards prevention, and technologies. We summarize established and emerging papers related to both regional studies on catchment erosion and management, as well as channel processes modelling and hydrogeochemical impact in streams and rivers. Finally, we discuss future directions and challenges to bridge scientific and management gaps by promoting a holistic understanding of river systems and catchment conditions.

The influence of aerosols on the Arctic system remains associated with significant uncertainties, particularly concerning black carbon (BC). The polar aerosol station “Island Bely” (IBS), located in the Western Siberian Arctic, was established to enhance aerosol monitoring. Continuous measurements from 2019 to 2022 revealed the long-term effects of light-absorbing carbon. During the cold period, the annual average light-absorption coefficient was 0.7 ± 0.7 Mm−1, decreasing by 2–3 times during the warm period. The interannual mean showed a peak in February (0.9 ± 0.8 Mm−1) then 10 times the lower minimum in June and exhibited high variability in August (0.7 ± 2.2 Mm−1). An increase of up to 1.5 at shorter wavelengths from April to September suggests contribution from brown carbon (BrC). The annual mean equivalent black carbon (eBC) demonstrated considerable interannual variability, with the lowest in 2020 (24 ± 29 ng m−3). Significant difference was observed between Arctic haze and Siberian wildfire periods, with record-high pollution levels in February 2022 (110 ± 70 ng m−3) and August 2021 (83 ± 249 ng m−3). Anthropogenic BC contributed 83 % to the total for the entire study period, and gas flaring, domestic combustion, transportation, and industrial emissions dominated. During the cold season, > 90 % of surface BC was attributed to anthropogenic sources, mainly gas flaring. In contrast, during the warm period, Siberian wildfires contributed to BC concentrations by 48 %. In August 2021, intense smoke from Yakutian wildfires was transported at high altitudes during the region's worst fire season in 40 years.

Biomass burning (BB) has a major impact on air quality and population health, with the brown carbon (BrC) of special concern as an important source of pollution and absorbing incoming radiation. The impact of BB was quantified in an urban area of Moscow, the northern gas-fuel heated European megacity, during warm and cold seasons. Real-time measurements of aerosol optical properties were performed by an aethalometer. Heating and non-heating periods are marked by Absorption Angstrom exponent (AAE) equal 1.1 and 1.2, spring agricultural and summer wildfires by 1.3 and 1.4, respectively. Light absorption babs of 10 f 9 Mm-1 at 880 nm and 29 f 27 Mm-1 at 370 nm was independent on heating activity. No significant seasonal difference was revealed by mass absorption coefficient for black carbon (BC) of 13.5 m2 g-1 and BrC of 0.9 m2 g-1. BC contribution to total absorption dominated in all wavelength ranges and seasons. During heating period, BrC contribution to total absorption at 370 nm (%babsBrC) was 16 f 21 %, lower than in other European and Asian megacities where populations widely burn biomass and coal. It was 24 f 31 % in spring due to agricultural fire impact and increased BB activity because of the population migration out of the city during the May holiday. Ryazan wildfire plumes affected Moscow, with babs(880) and babs(370) increase 1.7 and 2.4 times, respectively, with a high % babsBrC of 37 +/- 59 %, and strong BrC absorption capacity in both day and nighttime. The relative absorption forcing of BrC compared to BC was estimated to range between 36.2 +/- 1.1 % and 29.8 +/- 2.7 % in ultraviolet and visible radiation range, respectively. Backward trajectory cluster and concentration weighted trajectory analyses revealed the regional origin of BB sources, coinciding with areas of observed wildfires. Collocated 12 h sampling and chemical composition analyses of BB tracers (levoglucosan and K+) identified the emission sources by significant correlations with BrC absorption. Four factors of BrC apportionment were identified via positive matrix factorization, showing contributions from fossil fuel combustion and secondary organic (82 %), and BB (18 %). As a result, regional population activity and spring and summer wildfires highlighted the uniqueness of Moscow as the northern gas-fuel heated megacity for BB impact studies in Europe and Asia.

The content of 39 metals and metalloids (MMs) in submicron road dust (PM1 fraction) was studied in the traffic zone, residential courtyards with parking lots, and on pedestrian roads in parks in Moscow. The geochemical profiles of PM1 vary slightly between different types of roads and courtyards but differ significantly from those in parks. In Moscow, compared to other cities worldwide, submicron road dust contains less As, Sb, Mo, Cr, Cd, Sn, Tl, Ca, Rb, La, Y, U, but more Cu, Zn, Co, Fe, Mn, Ti, Zr, Al, V. Relative to the upper continental crust, PM1 is highly enriched in Sb, Zn, Cd, Cu, W, Sn, Bi, Mo, Pb. In the courtyards, where contact between pollutants and the population is most frequent and occurs over an extended period, the level of PM1 pollution with MMs (from strong to extreme) is comparable to that on large roads. Source identification was conducted using correlations, elemental ratios, and absolute principal component analysis with multiple linear regression (APCA-MLR). In the traffic zone, non-exhaust and exhaust vehicle emissions contribute significantly to the MM concentrations in PM1 (especially for Bi, Sb, Sn, V, Fe, Cu, W, Mo); soil particles, abrasion of steel surfaces, industrial emissions, tire and road wear with carbonate dust resuspension contribute less. In the courtyards, the contribution of the road wear with carbonate dust resuspension and soil particles increases by up to 16

The study aimed to assess the accumulation levels, spatial distribution, and sources of the potentially toxic elements (PTEs), such as Zn, As, Cd, Pb, Cr, Co, Ni, Cu, Sb, Mo, V, W, Sr, Mn, Bi, Sn, Fe, Cs, Be, and Ba, in urban soils, road dust and their PM10 fractions in Yalta, a seaside resort town of the Crimean Peninsula. The concentrations of the PTEs were measured in the urban topsoil (0–10 cm), road dust, and their fine particles, < 10 μm in diameter (PM10), using ICP-MS and ICP-AES methods. The soil and road dust samples were collected in 2018 in various functional zones of Yalta and on different types of roads. In total, 69 soil samples and 57 road-dust samples were taken. The PM10 fraction was isolated by sedimentation method according to Stokes' law. The urban soils and the road dust were contaminated by Pb, Sb, Zn, Sn, Cd, Cu, Bi, Mo, and Mn. The finer particles (PM10) separated from the urban soils and the road dust showed higher accumulation of the PTEs than the bulk samples. The contribution of the PM10 fraction to the total amount of the pollutants in the bulk soil and road-dust samples accounted for 50–80

The article suggests a method for calculating emissions from the autonomous heating systems (AHS) of individual residential buildings based on the assessment of the number and area of farmsteads using remote sensing data, the volume and type of fuel and the type of combustion according to population surveys data and data provided by the administrations of municipal districts and settlements. The importance of AHS as a source of atmospheric pollution was evaluated at three spatial levels: the regions of Russia, where the AHS are of the greatest importance, were identified according to the structure of fuel consumption; the emissions from the combustion of residential heating fuel were calculated for the municipalities of the Baikal natural territory (BNT) and the types of territories were identified according to the structure of emission sources; and the role of AHS in air pollution of the residential areas was assessed for settlements. AHS are the dominant air pollution source (over 90%) for most of the BNT territory. Unlike CHPPs and boiler facilities, emissions from individual residential buildings using coal and firewood in most cases significantly affect air quality (up to 4,9 MPC of particulate matter and sulfur dioxide), and the areas of such impact are limited to the residential area of settle-ments. Strategies to reduce pollution depend on the location of a territory, type of settlement, income levels, the current structure of fuel consumption, the presence of exploited coal deposits and other factors

Cities are highly interconnected systems where specific interactions between various urban environments occur due to the Urban Heat Island (UHI) and Urban Pollution Island (UPI) effects. Four compartments of the environment (atmospheric air, road dust, streamflow, and people) are discussed for Moscow city. Long-term meteorological, radiative, air quality, and precipitation measurements, the non -hydrostatic regional numerical COSMO model, and extensive hydrological and geochemical sampling were used. To characterize mortality and UPI interaction, a family of distributed lag non-linear models (DLNM) was applied. The study reveals increased aerosols concentrations which reduce the incoming solar radiation and increase the atmospheric longwave radiation. UHI strengthens the low -troposphere convergence due to urban breeze circulation and atmospheric circulation due to elevated surface roughness, the effect which leads to 11.6% heaviest precipitation increase compared to background values. Increased precipitation doubles streamflow rates and enhances the contribution of rain floods to annual flow. Similar geochemical associations with Sb, W, Zn, Cd, Pb, and Cu were found in aerosol PM 10 , indicating transport and road dust impact. Finally, associations between high temperatures and human mortality which are generally stronger at high levels of air pollution for both PM 10 and NO 2 , and for lag 1 day and 2-6 days are discussed.

The article developed an algorithm for the integral assessment of anthropogenic impact (AI) with spatial discreteness for municipalities of the Baikal Natural Territory (BNT). It includes 21 normalized indicators for the 2014–2020 period, aggregated into 7 sub-indices (impact on the atmosphere, water, forest resources, agricultural impact, solid waste, disturbed lands and objects of accumulated harm, as well as background impact). To determine the weight of the indicators, a survey was conducted of experts representing the scientific community (specialists in the field of integrated assessments of certain types of impacts or in the field of environmental problems of the BNT), the expert community (leading rating agencies) and representatives of the environmental management system of the regions included in the BNT. The integral indicator made it possible to build a rating of municipalities and identify key factors in the formation of the environmental situation. According to the integral index, five types of territories are identified, subtypes are distinguished by the nature of the impact on the environment. A high level of AI is typical for large cities and localities of enterprises, especially mining, in which a full set of load components operates. The increased level is observed in cities, suburban municipalities with a high burden from the vital activity of the population, as well as in large agricultural areas with a developed extractive industry. The average level of AI is typical for a small number of rural areas and small towns due to the load from agriculture and forestry. The reduced level of impact is formed mainly in semi-peripheral areas, where the load on forest resources plays a special role, and some suburban areas with more developed agriculture. A low level of AI is typical for peripheral, sparsely populated municipal units with a noticeable proportion of pollution from heating oil in residential housing. For BNT, a special role in the formation of the ecological situation is played by large tracts of disturbed land, high volumes of solid waste generation and objects of accumulated damage left over from the period of Soviet industrialization.

Assessments of air quality in industrial cities are receiving much attention, especially in regions sensitive to the ecological and climate changes. The atmospheric aerosol loading was studied in the city of Novy Urengoy during the summer–autumn of 2023. Particle number concentration and the mass concentration of particles with a size less than 10 µm (PM10) and 2.5 µm (PM2.5), as well as black carbon (BC), were measured by the mobile Aerosol Complex. The portion of fossil fuel combustion (FF

The content of 17 individual polycyclic aromatic hydrocarbons (PAHs) was analyzed in samples of background and urban soils obtained during a geochemical survey of the territory of Ulan-Ude in the summer of 2022 for the first time. The average content of PAHs in the urban soils is 801 ng/g, which is more than 8.5 times higher than the level in background chestnut soils. The soil cover is contaminated primarily with medium- and high-molecular-weight PAHs. The proportions of individual PAHs in the soils of Ulan-Ude range within 4–11

Wildfires in Siberia generate large amounts of aerosols, which may be transported over long distances and pose a threat to the sensitive ecosystem of the Arctic. Particulate matter (PM) of aged wildfire plumes originating from Yakutia in August 2021 was collected in Nadym and on Bely Island (both in northwestern Siberia). An advanced analysis of the chemical composition of aerosol particles was conducted through a multi-wavelength thermal–optical carbon analyzer (TOCA) coupled to resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) as well as through ultra-high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). In Nadym, concentrations of organic carbon (OC) and elemental carbon (EC) peaked at 100 and 40 µg m−3, respectively, associated with Angström absorption exponents for 405 and 808 nm (AAE405/808) between 1.5 and 3.3. The weekly average on Bely Island peaked at 8.9 µg m−3 of OC and 0.3 µg m−3 of EC and AAE405/808 close to unity. In particular, ambient aerosol in Nadym had a distinct biomass burning profile with pyrolysis products from carbohydrates, such as cellulose and hemicellulose, as well as lignin and resinoic acids. However, temporarily higher concentrations of five- and six-ring polycyclic aromatic hydrocarbons (PAHs), different from the PAH signature of biomass burning, suggest a contribution of regional gas flaring. FT-ICR MS with electrospray ionization (ESI) revealed a complex mixture of highly functionalized compounds, containing up to 20 oxygen atoms, as well as nitrogen- and sulfur-containing moieties. Concentrations of biomass burning markers on Bely Island were substantially lower than in Nadym, flanked by the appearance of unique compounds with higher oxygen content, higher molecular weight, and lower aromaticity. Back-trajectory analysis and satellite-derived aerosol optical depth suggested long-range transport of aerosol from the center of a Yakutian wildfire plume to Nadym and from the plume periphery to Bely Island. Owing to lower aerosol concentrations in the plume periphery than in its center, it is demonstrated how dilution affects the chemical plume composition during atmospheric aging.

Globally the impact of COVID-19 lockdown on environmental pollution is evidenced. How significant it was due to social and working restrictions during different pandemic waves is still uncertain. Aerosol black carbon (BC) in the Moscow megacity background is measured during first wave COVID-19 lockdown and recovery periods in spring and summer of 2020, and at the same times in 2021 when pre-lockdown and lockdown of the third pandemic wave occurred. Economic and population activities in conjunction with meteorological parameters and air mass transportation are evaluated by studying the variability and concentration levels of black carbon. Because the strict social and working restrictions in lockdown 2020 the mean BC concentration dropped down to 1.5 ± 0.9 µg m−3. The portion of biomass burning (BB

High population and a wide range of activities in a megacity lead to large-scale ecological consequences which require the assessment with respect to distinct characteristics of climate, location, fuel consumption, and emission sources. In-depth study of aerosol characteristics was carried out in Moscow, the largest megacity in Europe, during the cold period (autumn and winter) and in spring. PM10 chemical speciation based on carbonaceous matter, water-soluble ions, and elements was carried out to reconstruct the PM mass and evaluate the primary and secondary aerosol contribution. For the whole study period organic matter, mineral dust, and secondary inorganic/organic accounted for 34, 24, and 16 % of PM10 mass, respectively. PM10, OC, and EC approached a maximum in spring and decreased in winter. Mineral dust seasonal fraction increased from spring (17 %) to autumn (32 %), and then decreased in winter (22 %). Secondary inorganic aerosols (SIA) in opposite showed the maximum 27 % in winter. K+ marked the residential biomass burning in the region surrounding a megacity in spring and autumn, agriculture fires in spring. In winter primary aerosol contribution dropped down 56 % while secondary approached practically equal 44 %. Source factors with the relative contributions are quantified, namely city dust (26 %), traffic (23 %), industrial (20 %), biomass burning (12 %), secondary (12 %), and de-icing salt (7 %); they were significantly varying between the cold heating period and springtime. The relevance of sources to meteorological parameters and mass transportation is investigated by using both bivariate polar plots and Lagrangian integrated trajectory (HYSPLIT) model. Trajectory clustering demonstrates regional sources being crucial contributors to PM10 pollution. Aerosol speciation and source apportion factors identify the differences of the Moscow urban background among large European and Asian cities due to northern climate conditions, fast construction, long-range transport from industrial -developing area surrounding a city, regional biomass burning preferably in spring and autumn, and winter road management.

An indicator of urban environmental pollution can be road dust, which is formed by the participation of many anthropogenic sources. For Moscow, the main source of heavy metals and metalloids (HMMs) is motor transport which emissions are toxic. Pollutants in fine fractions of road dust are easily blown into the air, then enter the human body and pose a health risk. This work is devoted to assessing the spatial distribution and environmental hazard of HMMs accumulation in road dust and its fine fractions PM1-10 and PM1 in the Central Administrative Okrug (CAO) of Moscow based on field data for 2023. The list of priority pollutants coming with technogenic emissions in the CAO includes Sb, Zn, Cu, and Cd, as well as Sn, Pb, Mo, and W. In fine fractions, the mean content of these HMMs is an order of magnitude higher; its variability is lower, while the differences in the contents of the elements in dust from roads with various traffic intensities become more contrasting. Differences between the roads are caused by intensity, average speed, and mode of the traffic, as well as by the composition of the vehicle fleet and the frequency of traffic jams. Extremely high and dangerous pollution in the PM1 fraction was found in about 85% of samples; the average for the okrug total pollution index for this fraction is 1.4 times higher than for the PM1-10 fraction.

Atmospheric precipitation acts as a significant pathway for pollutants from the atmosphere to the Earth’s surface, and analyzing urban precipitation data on intensity, fallout regime, transfer patterns, and solid particle content helps identify pollution sources. For the first time in the Moscow megacity, the levels of soluble forms of potentially hazardous elements (PHEs) in atmospheric precipitation were studied during the whole summer season of May–September 2019. The concentrations of Al, As, B, Ba, Be, Bi, Cd, Ce, Co, Cu, Fe, La, Li, Mn, Ni, P, Pb, Rb, Sb, Sn, Sr, and Zn were determined using inductively coupled plasma mass spectrometry and atomic emission spectroscopy methods. The research underscores the crucial role of atmospheric precipitation in washing PHEs out of the atmosphere. In May and September, concentrations of PHEs surpass the warm-season average. Notable contamination in May stems from elevated traffic during vacations, extensive burning of plant debris and wood, and pollen transport. Summer months are characterized by reduced forest and agricultural fires, traffic, and increased vegetation, leading to lower PHE concentrations, especially in July, with typical amount of precipitation contributing to pollutant dispersion. Elevated PHE levels in September are observed due to increased traffic load, biomass burning, and the expansion of unvegetated soil areas. Rainwater is enriched with Sb, Pb, Cd, Zn, Cu, B, Bi, P, and Sr, sourced from vehicle emissions, soil particles, industry, construction dust, biomass burning, and forest fires. Moderate enrichment with Ba, Mn, Ni, Co, and Sn also occurs episodically. Regression analysis highlights solid particles’ role as a major PHE source in rainwater, with the longer antecedent dry periods and the higher acidity level of rain intensifying the accumulation of PHEs. Long-range transport plays a lesser role, with Southern and Northern Europe, Western Siberia, and the central part of European Russia contributing meaningfully.

The distributions of potentially toxic elements (PTEs) among PM1, PM1–10, PM10–50, and PM50–1000 fractions of the road dust were studied in the western and eastern parts of Moscow, impacted mainly by the road transport and the industrial sector, respectively. The partitioning of PTEs in road dust can provide more precise information on pollution sources and its further interpretation regarding human health risks. The concentrations of PTEs were analyzed by mass and atomic emission inductively coupled plasma spectrometry. Differences in the results between the western and eastern parts of the city were caused by the dissimilarity between traffic and industrial emissions. The source apportionment of the PTEs was carried out using absolute principal component analysis with multiple linear regressions (PCA/APCS-MLR). The contribution from anthropogenic sources was significant to PM1 and PM1–10 particles. In coarser fractions (PM10–50, PM50–1000), it decreased due to the input with the wind-induced resuspension of soil and rock particles. In the eastern part of the city, the accumulation of PTEs (especially Mo, Sb, Cd, Sn, Bi, Co, and As) is the most active in PM1–10, while in the western part, it is most pronounced in PM1 (especially Pb, Cu, Cr, and W) which is associated with differences in the size of particles coming from traffic and industrial sources. In the eastern part of Moscow, in comparison with the western part, the contribution from industrial sources to the accumulation of PTEs in all particle size fractions was higher by 10–30