Home – Home – Jornals – Atmospheric and Oceanic Optics 2024 number 6

Contribution of carbonyl compounds into the generation of atmospheric organic aerosol in the presence of typical urban air pollutants is investigated. Aldehydes and ketones entering the atmosphere from natural and anthropogenic sources are identified by means of high-performance liquid chromatography. Field measurements were carried out on the territory of Novosibirsk scientific center and in adjacent forest areas. It is shown that the transport of typical gaseous urban air pollutants (nitrogen oxides and ozone) into the air of forest areas and the transport of biogenic compounds (alkenes and aldehydes) to the urban territory cause sharp changes of the kinetics and mechanism of organic aerosol generation in comparison with the processes taking place in typical urban atmosphere. Thus, in the presence of ozone, the yield of aerosol products from formaldehyde, acetaldehyde, and propanal photonucleation increases by a factor of 4-8, while for benzaldehyde and acrolein it exhibits 5- and 30-fold decrease, respectively. For aromatic substituted aldehydes and furfural, aerosol yield slightly increases (only up to 30 %). The results make it possible to carry out quantitative evaluation of the capacity of natural and anthropogenic sources of organic aerosol in the forest-steppe zone of Western Siberia and predict the biological effect of aerosol generated in the presence of various pollutants.

Dust aerosol from the areas of sandstorms is transported by air masses for thousands of kilometers, affecting the optical properties of the atmosphere, climate, and terrestrial natural objects. The northern Caspian region - the territories of Kalmykia, the Volga Delta, the Transcaspian lowlands and northwestern Kazakhstan - is a year-round source of dust aerosol. The increase in the level of aerosol pollution in the near-surface Moscow air, associated with long-range atmospheric transport of dust from the Caspian regions, is analyzed according to continuous observation data at the stations of the State Budgetary Institution Mosecomonitoring during 2011-2021. We have revealed eight months (about 6%) with episodes where the daily PM₁₀ concentration in Moscow was higher than the MPC. Their duration ranges from 3 to 10 days and on average does not exceed 9% of the total number of days per year. The maximal values of daily PM₁₀ concentration in the near-surface city air during such episodes are 2.7 ± 1.1 times higher than the corresponding monthly average ones. The months with episodes of long-range atmospheric dust transport to Moscow are characterized by increased air temperature by 1.9 ± 2.0 °C and reduced precipitation by 9 ± 13 mm on average relative to the corresponding norm values for Moscow.

Electrical processes in a wind-sand flux has been studied. According to synchronous measurements in a deserted area in the Astrakhan region, the density of saltation electric currents and currents caused by the transfer of charged dust aerosol particles at heights of 4 and 12 cm are received. The statistical characteristics of variations in the density and density moduli of these currents are calculated. It is shown that in a wind-sand flux in the height range from 4 to 12 cm, the density modules of saltation electric currents and currents caused by the transfer of dust aerosol decrease with height much more slowly (logarithmic gradients are -0.025 and -0.07 cm^-1) than the concentration of saltating particles (logarithmic gradient is -0.32 cm^-1). It is confirmed that the moduli of saltation electric current density correlate with each other and with wind speed in the surface air layer more closely than the current densities themselves. It is of great interest to study the influence of electrical processes in wind-sand flux on the dynamics of saltation.

Based on three years measurements, the dependence of the concentrations of cultivated microorganisms and total protein on meteorological parameters (wind direction and speed, solar radiation, temperature, atmospheric pressure, relative and absolute humidity) is studied. Sampling was carried out at the site of the FBRI State Scientific Center for Virology and Biotechnology “Vector” of Rospotrebnadzor, Koltsovo, Novosibirsk region, with simultaneous recording of weather conditions. The concentration of total protein was determined by the fluorescence method of the protein binding reagent, and the concentration of cultivated microorganisms by standard cultural methods. Weather data came from a weather station located near the sampling site. Analysis of the data obtained shows that the concentrations of biological components in aerosol increase with the average temperature, absolute humidity, and illumination during sampling and decrease with an increase in the average relative humidity, wind speed, and atmospheric pressure.

The first results of summer field observations of the microphysical characteristics of ultrafine aerosol particles in the near-surface layer of the atmosphere in the dry steppe zone of southern Russia in 2021 and 2022 are considered. Taking into account the synoptic and meteorological conditions, the daily changes in concentration and size distribution of ultrafine aerosols, as well as their short-term variability are studied. The constant presence of Aitken particles is established at any time of the day and under any meteorological conditions. Minimal concentrations of nucleation particles and Aitken particles are detected at night and in the early morning. The highest rate of generation of nucleation particles is typical for the morning hours, when photochemical processes are activated, thus causing the morning maxima of concentrations of nucleation and Aitken particles. During the night hours, an increase in the concentration of transient subfraction particles is observed. The features of the short-period variability of ultrafine aerosols in the dry steppe zone of southern Russia are discussed taking into account the general pattern of daily aerosol generation dynamics and subsequent particle growth in the atmosphere, as well as by comparing with the results of observations of ultrafine aerosols in some other regions of the world.

Infectious diseases affecting the respiratory system are currently a serious medical problem. One of the ways to increase the effectiveness of therapy for such diseases is targeted delivery of drugs. This approach requires the development of new methods for generating aerosols of drugs, with the help of which it is possible to obtain particles with sizes that allow them to penetrate into specified areas of the respiratory system. In this work, a method for generating dry aerosol particles based on ultrasonic spraying of a drug solution is proposed and implemented. Using the example of a solution of the medicinal antifungal substance fluconazole, it is shown that this method enables generating aerosol with a stable concentration and an average size of particles for more than 2 hours. The resulting aerosol has optimal inhalation parameters: size from 1 to 1.9 microns and count concentration of 70,000 ± 6500 cm^-3. The presented method makes it possible to further study the biological effect of aerosols of drugs.

A description of the designed automated complex is presented. The results of measurements of the content of species with different volatility in six particle size ranges from 0.3 to 5 μm with artificial heating from 25 °С to 100 and 200 °С are discussed. The particle concentration was recorded by an optical counter. The instrumentation complex was tested in the period 2021-2023 in separate series of round-the-clock observations in different seasons. It has been shown that variations in the relative content of soluble sulfur compounds according to the counter data are in good agreement with the variability of the values of the parameter of condensation activity. In general, we believe that the use of this method will make it possible to obtain additional information about the seasonal and diurnal variations in aerosol composition in the intermediate range of particle sizes.

The measurement complex including diffusion aerosol spectrometer, optical aerosol spectrometer, and aerosol mass concentration meter has been developed and manufactured at the Institute of Chemical Kinetics and Combustion SB RAS. Laboratory tests of the instruments included in the measurement complex were carried out using standard test systems. Comparison of measured particle size values with the data obtained by independent methods (transmission electron microscopy and measurement of particle sedimentation velocity) revealed their good agreement. It is demonstrated that the measuring complex is suitable for determining concentrations and sizes of aerosol particles within wide ranges with the real-time presentation of results both in laboratory and in situ experiments.

Gaseous elemental mercury (GEM) is the predominant form of mercury in the atmosphere. As a result of deposition, it enters terrestrial and aquatic ecosystems, where it is further transformed into the ecotoxicant methylmercury. The work is devoted to the study of gaseous elemental mercury (GEM) in atmospheric air and total mercury in atmospheric precipitation in the Southern Baikal region. Sampling was carried out at the monitoring station Listvyanka (51.9° N, 104.4° E) in 2022-2023. Mercury concentration in air was measured by mercury gas analyzer RA-915AM (St. Petersburg, Russia). The concentration of total mercury in precipitation was determined by PND F 14.1:2:4.271-2012, method A (permanganate mineralization). Statistical analysis of data on mercury content in atmospheric air and precipitation is performed. During the period under study, the concentration of GEM in atmospheric air averaged 1.61 ng/m³. The analysis showed that the pair correlation coefficient throughout the period under study was 0.47 between Hg⁰ and sulfur dioxide (SO₂) and 0.44 between Hg⁰ and nitrogen dioxide (NO₂). In 12 cases, a strong positive correlation (> 0.9) between Hg⁰, SO₂, and NO₂ was observed. For each episode of mercury concentration above 2.0 ng/m³, back trajectories of air masses were calculated using the HYSPLIT model. The trajectory analysis also confirmed our assumption of a common type of source for mercury and minor gas impurities. The weighted average content of total mercury in precipitation is 44 ng/L, the median value is 29 ng/L, and the maximum is 282 ng/L. We have supplemented the existing ideas about mercury content in the atmosphere of the Southern Baikal region. It was found that despite the significant distance from large cities, the mercury content in atmospheric precipitation on the shores of Lake Baikal is comparable to the results obtained in urban agglomerations of Nepal, Canada, Korea, and China.

Experimental studies of the composition of atmospheric air are the basis for subsequent numerical analysis of pollution processes and management decisions to improve the quality of the urban environment. The processes of long-term air pollution in Irkutsk and the influence of calm conditions on them are studied. An analysis of linear correlations between the measurements of monthly average concentrations of benzo(a)pyrene at stationary posts for monitoring the composition of atmospheric air in the city is performed. It is shown that the results of intra-annual pairwise measurements at posts, in general, are proportionally correlated to each other. The relationships between benzo(a)pyrene concentrations and calm conditions were studied. A correlation between its high concentrations in winter and the frequency of calm weather conditions is revealed. The established patterns create opportunities for external monitoring of observation results at stationary monitoring posts in the city. The derived dependencies allow you to numerically fill gaps in observational data. The results can be used when planning measures to improve the quality of atmospheric air and constructing models for assessing concentration fields.

There is considerable uncertainty about the methane emission from the Arctic shelf seas. Methane fluxes in this region can be underestimated and play a significant role due to the large volume of gas contained in bottom sediments in the permafrost and gas hydrates. We have analyzed the model sensitivity to the parametrization of gas exchange processes on the sea surface. The study is based on the numerical modeling results of the transport of dissolved methane in the seas of the Arctic. The dissolved methane transport model is included in the basic model of the ocean and sea ice developed at the Institute of Computational Mathematics and Mathematics, Siberian Branch, Russian Academy of Sciences. Estimates of methane emissions into the atmosphere were made with various parametrization of the gas exchange process in the "water - atmosphere" and "water - ice - atmosphere" systems using NCEP/NCAR reanalysis data. The uncertainty of the estimate of annual methane emission amounted to 6-12% when considering different dependencies of gas exchange on wind. The scheme accounting the ice cover has a more pronounced influence on the flux: the uncertainty increased to 50-130%. Parameterization of the relationship between ice cover and gas exchange can have a great influence on the calculated methane fluxes and lead to underestimation of its emission from the seas of the Arctic shelf.

The main source of summer heating of the upper layer of the Siberian Arctic shelf seas is shortwave solar radiation. The radiation flux attenuates as it passes through the water column, and the attenuation rate is determined by the optical properties of water, depending mainly on the concentration of suspended matter in the water. In numerical models of the ocean and sea ice, the process of absorbation of shortwave solar radiation is described by various parameterizations. In the present work, the sensitivity of the regional 3D numerical ocean and sea ice model SibCIOM to two parameterizations of the penetrating radiation is studied: (1) two-component parameterization using constant attenuation coefficients for the infrared and visible parts of the spectrum depending on one of the 10 transparency classes of ocean waters; (2) a three-component one, with different absorption coefficients for the red, green, and blue parts of the visible spectrum and relying on satellite data on chlorophyll concentration. Analysis of the results of numerical experiments for the water area of the Siberian shelf seas has shown that taking into account the seasonal distribution of chlorophyll concentration when forming the flux of penetrating shortwave radiation leads to the formation of regions of water warming in the surface or bottom layer, which differ from the basic experiment with two-component parameterization.

Atmospheric monitoring from global satellite navigation systems is usually used to estimate the integral water vapor of the atmosphere. In addition, such parameters as the zenith tropospheric delay of satellite radio signals and its gradient parameters characterizing atmospheric mesoscale irregularities measured with high temporal resolution. The work shows a significant variability of these atmospheric characteristics associated with sever convective weather phenomena. A sample of several hundred events of severe weather phenomena corresponding to available observations of the nearest satellite stations in the Republic of Tatarstan and Moscow region located at latitudes 55-56° N is used. It was found that under the conditions of severe weather phenomena, the inhomogeneity of the zenith tropospheric delay field of satellite signals strongly increases which manifested in the increase in its gradient parameters and their fluctuations, as well as in the growth of the integral water vapor. The intensity of fluctuations of integral water vapor most strongly changes if the station is located not further than 20 km from a hazardous phenomenon, which is explained by the size of convective cells. However, even at the station location at distances of up to 200 km from hazardous phenomena, an increase in the atmospheric integral water vapor and the effect of amplification of inhomogeneity as compared to mean multiyear data are observed.