Home – Home – Jornals – Atmospheric and Oceanic Optics 2026 number 6

The intense urbanization observed in the world is accompanied by the active growth of urban agglomerations. The largest Moscow agglomeration in Europe is currently dynamically developing, which leads to the emergence of additional factors contributing to changes in urban ecosystems, weather and climate. One of the indicators of such processes is the variability of the properties of atmospheric aerosols. In this study, the main types of natural and anthropogenic impacts and their characteristic features are identified. To this end, a comprehensive algorithm for assessing the indicators of typical aerosol pollution of the city atmosphere and classifying impacts has been developed based on the results of continuous six-year (2020-2025) experimental observations at IAP RAS and measurements from the Mosecomonitoring network. The results can be used to clarify the aerosol emissions in Moscow, in chemical transport models, and in assessing and forecasting the state of urban ecosystems and climate.

To study the influence of three-dimensional cloud effects on the forecast of longwave radiation and air temperature during warm air advection onto a snow surface for the Moscow region, experiments were conducted with the ICON v.2025.04 model using various algorithms of cloud heterogeneity accounting. Additionally, experiments were conducted with the ecRAD radiation scheme in autonomous mode. The ICON model with the McICA algorithm reproduces positive NLR values, but underestimates them. The use of the SPARTACUS algorithm, which makes it possible to describe the three-dimensional effects of clouds, reduced the NLR RMSE by 4 W/m². At the same time, in the ecRAD autonomous mode, the effects reached 15 W/m², which corresponded to the measured NLR values within the measurement error. The study showed that the decrease in the effect of the SPARTACUS algorithm in the ICON model is associated with the influence of the algorithm on the cloud properties. Using the ecRAD autonomous mode, nonlinear NLR dependence on the cloud liquid water path and ice water path have been revealed. The temperature sensitivity to NLR changes was 2.7 °C per 100 W/m² in model experiments with McICA and 4.9 °C per 100 W/m² in experiments with SPARTACUS for night hours with positive NLR. Differences in the temperature response of the ICON model to changes in longwave radiation due to the replacement of the algorithms are also estimated.

Soot aerosol particles (black carbon) significantly contribute to atmospheric heating by effectively absorbing radiation across a wide range of wavelengths and, along with greenhouse gases, play an important role in climate change. The hypothesis of volcanogenic soot in the stratosphere (a possibility of formation of black carbon nanoparticles during Plinian volcanic eruptions and their casting to high altitudes) is critically analyzed. Features of thermal decomposition of methane and formation of reduced carbon in a two-phase gas-ash volcanic column are discussed. Known data on the detection of carbonaceous particles in the atmosphere, their properties, and possible, but not yet confirmed, connection with powerful volcanic eruptions are evaluated. The discovery of different reduced carbon forms in the ashes of modern volcanic eruptions in Kamchatka (the phenomenon of volcanic carbon paragenesis) is commented on. Energy competition between two ways of formation of reduced carbon in the forms of soot nanoparticles and carbon products strongly mechanically bonded to pyroclastic material is discussed. The results can be useful for atmospheric aerosol physics and climatology in analyzing the main sources of black carbon in the atmosphere.

Aerosol particles formed during the atmospheric photooxidation of organic compounds have reactive functional groups on their surface, which may be responsible for the biological action of the organic aerosol. This work studies the kinetics and mechanism of atmospheric photonucleation of o-dichlorobenzene as a compound modeling chlorinated aromatic hydrocarbons, known for their stability against environmental factors. The concentrations and sizes of the formed particles were measured using a diffusion spectrometer of aerosol; the composition of gas and aerosol products of photonucleation was determined by high-performance liquid chromatography and gas chromatography - mass spectrometry. The effect of water vapor and hydrogen peroxide on the yield and composition of aerosol products was studied. The pathways leading to the formation of identified products were determined relying on the data on the rate constants of elementary stages involved in nucleation. It is shown that atmospheric photonucleation of dichlorobenzene does not lead to the photochemical generation of ozone in the surface air layer. Quite contrary, the products of dichlorobenzene photolysis participate in the processes that cause ozone destruction. On the basis of the data obtained, the contribution from emissions containing chlorinated aromatics into the formation of organic aerosol in urban air is assessed qualitatively. The presence of reactive functional groups in the aerosol products allows us to assume that the aerosol may cause negative biological action. The results of investigation can be used to model photochemical processes in polluted urban air.

Cloudiness is one of the main factors determining the processes of radiation transfer in the atmosphere; it plays a key role in the formation of the radiative balance of the Earth’s surface. The paper analyzes the impact of various single-layer cloud cover types on the shortwave balance of underlying surface (SBS) obtained using broadband flux simulation and long-term atmospheric remote sensing data for northern and southern regions of Western Siberia. Calculations performed for cloud characteristics averaged over the period 2001-2019 revealed that an increase in the cloud optical thickness decreases the daily SBS in summer from ~ 25 to ~ 8 MJ/m², while an increase in the underlying surface albedo in winter significant decreases the radiation balance, down to ~ 0.4-1 MJ/m². The presented estimates of the cloud radiative forcing (CRF) demonstrate its increase with the optical thickness of clouds from -60 W/m² (thin ice clouds) to -200 W/m² (dense cirrus clouds and middle-level clouds) in summer, and a significant decrease in the CRF modulus (to 4-7 W/m²) in winter. The SBS estimates can be considered as the regional averages for the cloud types under study.

The impact of a metropolis on the composition of near-surface air in the suburbs is one of the most pressing environmental problems. The work studies the influence of horizontal wind characteristics (direction, speed) on aerosol concentration in the near-surface air of Moscow megapolis and 50-60 km away from it. The data on PM₁₀ aerosol concentration obtained by the authors in the area of Zvenigorod (western suburb) and in the center of Moscow, as well as measured in Moscow at all atmospheric pollution control stations of the State Budgetary Institution “Mosecomonitoring” (megapolis) and in Pavlovsky Posad (eastern suburb). The “roses" of wind direction frequency, wind velocity, and PM₁₀ concentration at the points of observations in different seasons average over 2021-2024 are analyzed. Despite the predominant air mass transport from the west throughout the year in all three locations, the season average PM₁₀ fluxes have different directions and values both in the city and in the suburban points. In general, the annual PM₁₀ fluxes in near-surface air at the considered points have northerly direction, and they are higher in magnitude in suburban areas than in the city. The results can be useful in assessing environmental risks and public health in the Moscow Region, as well as for climate calculations and verification of their results.

Atmospheric transport is an important wave of supplying dispersed sedimentary matter (insoluble micro- and nanoparticles), including pollution, to the seas and oceans and their catchment areas. The study of dispersed sedimentary matter in the snow cover is of great importance, since it characterizes the winter atmosphere, when the surrounding land is covered with a layer of snow, and rivers and seas are covered with ice, and atmospheric supply of matter prevails. This article summarizes the results of the study of dispersed sedimentary matter in the snow cover (a natural archive of atmospheric deposition) of the Dvina Bay of the White Sea catchment area from 2016 to 2025. Snow was collected at the end of winter in pits down to frozen soil or lake ice. In the laboratory, the snow was melted and filtered through pre-weighed nuclear filters 47 mm diameter with a pore diameter of 0.45 μm. The particle composition was studied using a VEGA 3 SEM (Tescan) scanning electron microscope with an INCA Energy microprobe analyzer (Oxford Instruments). At points located in background areas, concentrations of insoluble particles in snow varied from < 1 to 10 mg/L. Significantly higher particle concentrations were observed in Arkhangelsk and its environs and at distances less than 100 m from roads. The dust load, not only at background points but also in the northern part of Arkhangelsk, is significantly lower than in many Russian cities. In background areas, dispersed snow sediment consists primarily of biogenic (plant fibers, spores and pollen, diatom valves) and lithogenic particles; near Arkhangelsk, soot and fly ash particles predominate. The results can be used for assessment of the impact of air transport of dispersed sedimentary matter on the state of ecosystems in the Dvina Bay catchment area, as well as for geoecological monitoring.

The biological component of atmospheric aerosols includes fungi, bacteria, viruses, and different natural and anthropogenic organic microparticles, which can affect the climate, atmospheric processes, and human health. Fungi are important multifunctional components of the microbiome of the atmosphere From April to August 2025, atmospheric aerosols were sampled on the territory of Koltsovo settlement, Novosibirsk region, with the aim of estimating the concentrations and biodiversity of fungi in them. Aerosol was sampled with the use of impingers with Hanks' medium; the resulting suspensions were inoculated onto nutrient media to isolate pure cultures and further study them. The fungi were identified by sequencing the nucleotide sequences (ns) of the fungal isolates' genomic DNA. The sequencing results yielded the ns of the fungal DNA marker regions, which were further identified by comparing them with the GenBank database using the BLASTn algorithm. The total number of microorganisms isolated from different aerosol samples significantly varied, from zero to 1.85 × 10⁴ CFU/m³. The concentration of fungi was significantly higher than the concentration of bacteria in many samples. Daily fluctuations in the concentration of fungi in the aerosols were ascertained. Widespread mold fungi Aspergillus, Aureobasidium, Candida, Fusarium, Penicillium, Cladosporium, etc. and higher fungi Trametes, Coprinellus, Bjerkandera, Phanerodontia, Schizophyllum, etc., were identified among the isolates, including saprotrophs and pathogens responsible for infections and allergic reactions in humans and animals. Our data indicate a need in monitoring studies of the atmosphere microbiome in order to assess its harmful effects on the regional environment and public health. The results can be used for distinguishing periods of the most active spore production by fungi in order to calendar the concentration of pathogenic fungal spores in the atmosphere and to develop timely preventive measures.

The problem of atmospheric air pollution by fine particulate matter (PM_2.5) in large industrial centers during winter is one of the most acute environmental threats affecting the life expectancy and quality of life of population. The study examines the processes of temperature inversion layer formation and its impact on atmospheric PM_2.5 in Krasnoyarsk during the winter months of 2022-2024 based on data from a monitoring network, which measures air temperature, atmospheric pressure, wind speed and direction, PM_2.5 concentration, and cloud cover, and data from an MTP-5 profiler, which determines the vertical distribution of atmospheric temperature. The multi-hour and multi-day regimes of radiation and advective inversions are analyzed. The necessary and sufficient conditions for their occurrence are established. The statistical dependences of PM_2.5 concentration on the category and intensity of inversions are derived. The results can be used in short-term forecasting of temperature inversions and the associated periods of high PM_2.5 air pollution in the city of Krasnoyarsk.

The role of vegetation in atmospheric chemistry is not limited to carbon dioxide absorption and oxygen evolution during photosynthesis. It is known that plant-emitted organic compounds (alkenes and aldehydes) participate in the generation of atmospheric aerosol. However, the mechanisms of related processes have been studied in detail only for alkenes. Our work assesses the effect of urban trees on air quality for the case of Novosibirsk. Tree species characterized by stability against urban air pollutants (nitrogen oxides, ozone, organic peroxides, and acids) were revealed, biochemical markers providing the stability of these species were determined, and the composition of volatile organic compounds emitted by these species was studied. Under laboratory conditions, the aerosol-forming ability of these compounds was studied, the mechanisms of their photooxidation were determined, and the yield of aerosol products was measured. For some species (aspen, birch, linden, poplar, and maple) used for greening in Siberian cities, the ability to absorb gaseous pollutants, such as formaldehyde, formic acid, and organic peroxides, has been discovered. On the basis of the data on absorption and emission of aerosol-forming components by trees, the contribution from urban green zones into the chemistry of organic aerosol was evaluated. It is shown that targeted greening of the cities with gas-absorbing tree species can reduce the aerosol load on residential areas by no less than 20-30%.

Under the current global warming, an increase in the water temperature in rivers flowing into the Arctic Ocean is becoming a significant factor, which not only affects the functioning of river ecosystems, but also increases river heat flux into the ocean. The latter could result in redistribution of heat over the ocean and further climate change. Based on decade average values of water temperature from 13 hydrological stations in the Middle and Lower Lena from 1990 to 2011, we study the relationship between air and water temperatures during the open-water period with the use of a regression approach. Quantitative estimates of river water temperatures under the climate change are performed. The use of air temperature as a predictor in a linear equation enabled us to assess monthly average water temperatures with acceptable accuracy. The results can be used in simulation of currents in the Laptev Sea.

Methods for numerical interpretation of satellite measurements of nitrogen dioxide with the use of a model for reconstructing long-term regional pollution from a high-altitude point source of atmospheric emissions are discussed. The model is based on asymptotic representations of impurity concentration fields at significant distances from the source. Numerical analysis of satellite measurements of nitrogen dioxide content in the area of the Gusinoozersk’s State District Power Plant (SDPP) was carried out. A high level of agreement was obtained between satellite observation data and model descriptions of concentration fields for nitrogen dioxide emissions from the power plant pipes in the southwest and northwest directions. The analysis revealed the presence of significant background concentrations of nitrogen dioxide caused by emissions from remote sources. The used assessment model also allows us to estimate the contributions of additional sources to the concentration fields of NO₂ emitted by the Gusinoozersk’s SDPP.