Characteristics Of Atmospheric Aerosols Research Articles

Characterization of Aerosol and CO2 Co-Emissions around Power Plants through Satellite-Based Synergistic Observations

The tracking of carbon and aerosol co-emissions is essential for environmental management. Satellite-based atmospheric synoptic observation networks provide large-scale and multifaceted data to help resolve emission behaviors. This study employs a comprehensive analysis of atmospheric dynamics, combustion byproducts, and aerosol characteristics around power plants. Strong correlations between Aerosol Optical Depth (AOD) at 500 nm and the column-averaged dry-air mole fraction of carbon dioxide (XCO2) were observed, revealing synchronous peaks in their emission patterns. The investigation into combustion completeness utilized metrics such as the ratio of carbon monoxide (CO)/XCO2 and Black Carbon Extinction (BCEXT)/Total Aerosol Extinction (TOTEXT). Discrepancies in these ratios across cases suggest variations in combustion efficiency and aerosol characteristics. Nitrogen dioxide (NO2) distributions closely mirrored XCO2, indicating consistent emission patterns, while variations in sulfur dioxide (SO2) distributions implied differences in sulfide content in the coal used. The influence of coal composition on AOD/XCO2 ratios was evident, with sulfide content contributing to variations besides combustion efficiency. This multifactorial analysis underscores the complex interplay of combustion completeness, aerosol composition, and coal components in shaping the air quality around power stations. The findings highlight the need for a nuanced understanding of these factors for effective air quality management.

Preparation, Characterization, and Scattering Characteristics of Mixed Aerosol of Fly Ash and Ammonium Sulfate

The mixed aerosols formed by fly ash and ammonium sulfate have a vital impact on the scattering characteristics of the atmosphere. This paper proposes to investigate the scattering characteristics of an individual optically levitated mixed aerosol of fly ash and ammonium sulfate using a coupled laser levitation and scattering measuring apparatus. The mixed aerosols were first prepared and characterized by multiple techniques. The results demonstrated that mixed aerosol particles completely encapsulated ammonium sulfate crystals on the rough porous surface of fly ash, resembling the “core-shell” structure. Moreover, the surface formed columnar ammonium sulfate crystals that exhibit the highest regularity when the solid mass concentration of fly ash was 1000 mg/L. The scattering intensity of mixed aerosols was measured, and the comparisons among fly ash aerosol and mixed aerosols were made to evaluate the effect of fly ash concentration on scattering. The measurements demonstrated that the mixed aerosols exhibited a lower overall scattering intensity compared to fly ash alone. The higher regularity of ammonium sulfate crystals formed on the surface of mixed aerosols at different solid mass concentrations of fly ash corresponds to higher scattering intensity. These findings will be helpful for recognizing the scattering characteristics of real atmospheric aerosols in depth.

Analysis of characteristics and changes in three-dimensional spatial and temporal distribution of aerosol types in Central Asia

Atmospheric aerosol types and characteristics have regional and seasonal characteristics mainly due spatial and temporal differences in emission sources and diffuse transport conditions. We explored regional three-dimensional spatial and temporal distribution characteristics of aerosol types in Central Asia from daytime to nighttime by using long-term (2007–2021) CALIPSO lidar measurements. The three results are as follows: (1) Average aerosol optical depth (AOD) values during the 14 years were 0.44 and 0.47 during daytime and nighttime, respectively, with an overall decreasing trend, among which the AOD in spring in the southern border region and in winter in the northern border region showed high values, 0.66 and 0.31 during daytime and 0.69 and 0.33 during nighttime, respectively, and nighttime AOD values were higher than those of daytime, possibly due to the lower signal-to-noise ratio of the CALIPSO during the daytime than during the nighttime. (2) The primary representative aerosol type in the Taklamakan Desert region being pure sand and dust, and more apparent winter-polluted sand and dust exist along the northern slope of the Tianshan Mountains in Xinjiang in winter than in other areas. High-altitude soot mainly existed below 4 km and was primarily concentrated in northern Central Asia, with the highest values (0.016 and 0.003) in summer and winter, respectively, which may be due to different diffusion and transport conditions. (3) Dust aerosols in spring were mainly concentrated in the region of 2–6 km in the Taklamakan Desert area; pure dust particles in summer and fall lifted height diffusion and gradually moved to the northern border region; polluted dust was mainly in northern Xinjiang in fall and winter and spread to northern Central Asia; and the average top height of aerosols in the transmission process reached the top of the troposphere, and transmission height was higher than source area.

Characteristics of aerosol at the research base “Ice Cape Baranova” in 2018–2023

Atmospheric aerosol plays an important role in the processes of radiative transfers and mass exchange by different substances in the “continent–atmosphere–ocean” system. In this paper we discuss the results of a five-year measurement cycle of the atmospheric aerosol characteristics at the polar station “Ice base Cape Baranov”, located on the Bolshevik Island (the Severnaya Zemlya Archipelago). The set of the characteristics analyzed includes: the aerosol optical depth (AOD) of the atmosphere; the ground concentration of aerosol particles in the radius range of 0.15–5 microns; the content of the absorbing substance (soot) in the aerosol in the equivalent of elemental black carbon. The average values of the aerosol characteristics for the general measurement period (from April 2018 to May 2023) were: volumes of submicron and coarse aerosol particles 0.43 and 0.46 μm3/cm3, respectively; mass concentration of black carbon — 45.8 ng/m3; AOT of the atmosphere at a wavelength of 0.5 µm — 0.08; Angstrom selectivity exponent — 1.67. The average annual variation of aerosol and black carbon concentrations is characterized by a maximum in winter (January–March) and a minimum in summer (June–August). A comparison is made against the data from analogous measurements of aerosol characteristics at the polar station in Barentsburg (the Spitsbergen Archipelago) and against the data from model calculations, i. e., MERRA-2 reanalysis. A distinctive feature of the data in the Cape Baranov area is the low content of coarse aerosol — 1.7 less than in Barentsburg. There is agreement with the annual variation of black carbon concentrations at other polar stations, but the opposite nature of the seasonal variability of model (MERRA-2) concentrations: low values in winter and high values in summer. It is shown that the average spectral AODs of the atmosphere at the “Cape Baranov” are intermediate values between the data from polar stations in NyÅlesund and Barentsburg.

Spatio-Temporal Variability of the Aerosol Optical Depth over the Gorky and Cheboksary Reservoirs in 2022–2023

The present study aimed to investigate atmospheric optical characteristics over the Gorky and Cheboksary Reservoirs and their multi-scale temporal variations to obtain the background characteristics and to identify events involving the transfer of absorbing aerosol to the studied region in 2022–2023. The region is located at a considerable distance (500 km) from the nearest AERONET station; therefore, previous atmospheric data were not available. As a solution, the in situ self-measured aerosol optical depth (AOD) and Angström exponent, as well as satellite products (MAIAC and CALIPSO) for MODIS data, were used. This allowed us to set background values of an AOD of 0.11 at a wavelength of 500 nm and an Angström exponent of 1.2, against their maximum values of 0.38 and 2.5, respectively. To explain these variations, the registered conditions and the microstructure of the dust aerosol over the studied region are presented. For days with background values, the analysis of the particle size distribution data did not show a predominance of any particle size. The optical properties of a smoke aerosol in an atmospheric column are described, and an analysis of the dynamics of particle size variability is presented. A comparative analysis of the optical characteristics of atmospheric aerosol over the Gorky and Cheboksary Reservoirs using in situ and MODIS products was carried out.

Insights into the chemical characteristics of atmospheric aerosols from urban-industrial and rural sites in south-east of Poland during winter

This study focusses on a short-term characterisation of atmospheric aerosols from three locations in south- east of Poland with different land use characteristics, population density and sources of pollution (Katowice: urban-industrial; Strzyżowice near Lublin: rural; Kielce: urban). Twenty-four hour PM2.5 and PM10 samples were collected on the quartz filter and their chemical compositions were monitored and measured using OCEC thermo-optical analysis and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS). The highest concentrations of PM2.5 and PM10 were measured at the urban-industrial area in Katowice (29.6 µg ∙ m−3 and 31.0 µg ∙ m−3, respectively), whereas the highest organic carbon (OC) and elemental carbon (EC) levels were observed at the Kielce urban site (23.3 ± 4.2 µg and 3.6 ± 0.3 µg, respectively). The lowest values were obtained at the rural site for PM2.5 (10.4 ± 2.7 µg ∙ m−3) and PM10 (11.8 ± 2.7 µg ∙ m−3) and for OC (17.8 ± 1.6 µg) and EC (1.0 ± 0.1 µg). SEM-EDS analysis of samples from Kielce allows identification of internal chemical mixtures of carbon, silicon, calcium, chlorine, sodium and aluminium.

Size-segregated aerosol measurements during Diwali festival in an elevated background location

Recent studies in the direction of identifying signatures of aerosol emission from fireworks stressed on the need of simultaneous measurements of mass, number and chemical compositional characteristics. Such an identification is tricky when the measurements are performed in an elevated background environment and/or in presence of an additional wide source term. This work studies the modifications in atmospheric aerosol characteristics due to firework induced emissions in Bathinda city of Punjab, North India. This study presents interpretations based on the results obtained from the measurements performed for 14 days covering the days of Diwali festival, 2021 as well as the baseline database gathered from a year-long campaign to measure mass concentration in different size-ranges. Highest mass concentration for the study duration was observed to be PM10- 382 μg/m3, PM2.5–299 μg/m3, PM1- 240 μg/m3, respectively in the month of November 2021. A clear increase of concentration was noted for Diwali days and the averaged concentration for PM10, PM2.5 and PM1 reached to 445 μg/m3, 363 μg/m3 and 304 μg/m3 on Diwali day, respectively. Number size distribution evolution analysis for the data measured from an optical particle counter (size range: 0.25–1 μm) showed that emissions for Diwali days occurred mostly at night times and in smaller size channels (<0.5 μm). Chemical compositional data of selected samples close to Diwali days was interpreted in terms of factor of increase of mass density of collected particles in different size-ranges. Mass density of elements K, Cl, S, Al, Zn, P, Mn, Pb, Br and Zr in PM1 samples was observed to be higher for Diwali days in comparison to their pre-Diwali levels. Few elements viz. Ba, Sr and Nb were found to be only present in the samples taken during Diwali days. In addition to Ba, Sr and Nb, elements V, Mg, Br and Se were observed to be present in PM2.5 and PM10 samples taken during the Diwali days. This study provides combined ambient aerosol characteristics during Diwali days when the air quality was affected by stubble burning as well.

Characterization of atmospheric aerosols by SEM-EDX in a rural-continental environment-a seasonal approach

The vital information on the morphology and composition of the atmospheric aerosols over any region is critical to understand their climatic and health effects. This work aims at the physicochemical characteristics of atmospheric aerosols at a rural continental site in northeastern India. We collected the aerosol samples from January to December 2018 and applied a seasonal approach to investigate the physical and elemental characteristics of aerosol particles. A Scanning Electron Microscope (SEM) has been used to examine the morphology of particles that, includes shape, size, and structure information. Energy-dispersive X-ray analysis (EDX) is used to investigate the elemental composition information. By using the SEM-EDX, we have noticed a variation in the morphology of particles and elemental composition from season to season. The different particle shapes vary from regular to irregular, including spherical, nearly spherical, triangular, capsule-like, and platy shapes have been observed. We have seen a variety of particle clusters, including chain-like structures, porous textures, soot structures, and irregular structures. A size range of particles with a diameter ranging from 100 nm to 30 µm has been observed. The presence of elements C, Si, O, B, K, Ca, P, S, Fe, Na, N, Cl, Mg, and Al has been examined in different seasons. We have noticed that road dust, crustal origin particles, and carbonaceous particles dominate the study region. We have observed a clear seasonal variation in the percentage of different elements. A small contribution by sea salt origin elements has also been noticed during the pre, monsoon, and post-monsoon seasons when winds flow from the marine region, and air mass back trajectory results support this.

First insights into the molecular characteristics of atmospheric organic aerosols from Iasi, Romania: Behavior of biogenic versus anthropogenic contributions and potential implications

The present study reports first data on the organic molecular composition and evolution of secondary organic aerosols (SOAs) markers in aerosol samples from an urban environment in Romania. Targeted and non-targeted approaches of liquid chromatography tandem with time-of-flight mass spectrometry (LC-ToF-MS) were used as powerful analytical approaches for aerosol characterization at the molecular level. Four distinct organic molecular groups (CHO, CHON, CHONS, and CHOS) were classified as relevant for both warm (with 847 assigned molecular formulae) and cold (with 432 assigned molecular formulae) periods. Different formation mechanisms, physico-chemical processing, meteorological conditions, and sources origin or strengths (biogenic versus anthropogenic), were identified as governing factors of the mass concentration size distribution for the first generation and second-generation oxidation products of α-/β-pinene and two nitroaromatics (i.e., 4-nitrophenol and 4-nitrocatechol). Aromaticity equivalent (XC), carbon oxidation state (OSC), H/C and O/C ratios, and van Krevelen diagrams, were used to discriminate between: i) the aliphatic or aromatic nature of the identified organic aerosol constituents, ii) the oxidation state of the aerosol samples (e.g., more oxidized molecular formulae during the highly insolated period, more intense photochemistry), and iii) sources role in controlling OAs constituents abundances and behavior (e.g., higher relative contributions of aliphatic CHO formulae with a wider range of carbon numbers and CHOS molecular group with higher contribution during the warm period due to increased biogenic emissions or secondary formation from the biogenic precursors). Since in the present study >88 % of the 4-nitrocatechol and 4-nitrophenol was determined in the aerosol size fraction below 1 μm, it is believed that determination of their abundances and size distribution in ambient aerosols might provide direction for future studies such as to enhance the knowledge on their toxic potential levels for the human health.

Application of Optimal Interpolation to Spatially and Temporally Sparse Observations of Aerosol Optical Depth

Aerosol optical depth (AOD) is one of the basic characteristics of atmospheric aerosol. A global ground-based network of sun and sky photometers, the Aerosol Robotic Network (AERONET) provides AOD data with low uncertainty. However, AERONET observations are sparse in space and time. To improve data density, we merged AERONET observations with a GEOS-Chem chemical transport model prediction using an optimal interpolation (OI) method. According to OI, we estimated AOD as a linear combination of observational data and a model forecast, with weighting coefficients chosen to minimize a mean-square error in the calculation, assuming a negligible error of AERONET AOD observations. To obtain weight coefficients, we used correlations between model errors in different grid points. In contrast with classical OI, where only spatial correlations are considered, we developed the spatial-temporal optimal interpolation (STOI) technique for atmospheric applications with the use of spatial and temporal correlation functions. Using STOI, we obtained estimates of the daily mean AOD distribution over Europe. To validate the results, we compared daily mean AOD estimated by STOI with independent AERONET observations for two months and three sites. Compared with the GEOS-Chem model results, the averaged reduction of the root-mean-square error of the AOD estimate based on the STOI method is about 25%. The study shows that STOI provides a significant improvement in AOD estimates.

Characteristics of Aerosol Extinction Hygroscopic Growth in the Typical Coastal City of Qingdao, China

The aerosol hygroscopic growth (HG) characteristics in coastal areas are very complex, which is one of the main influences on the simulation accuracy of radiation transfer modeling for coastal environments. Previous studies have shown that aerosol HG characteristics are very different in open oceans and inland regions. However, the aerosol HG features in coastal areas are strongly affected by its type. In this work, an aerosol backward trajectory tracing model was used to classify the local aerosol type. Using long-term field campaign data in Qingdao (25 September 2019 to 25 October 2020), the HG characteristics of different types of aerosols (i.e., land source, sea source, and mixed aerosol) under different seasons and different atmospheric environments (i.e., pollution background and clean background) were studied. Quantitative models of aerosol HG factor were established for aerosols from different sources in different seasons and under different pollution background conditions. The major type of local aerosol is terrestrial aerosol, as the marine source only accounts for 10–20%. Seasonal HG characteristics (deliquescence point, DP) of mixed and land source aerosol vary significantly, from around RH = 60% to RH = 85%, while that of the marine aerosol is rather consistent (RH = 80%). When the atmospheric background is relatively clean, the DPs of aerosols from different sources are almost the same (about RH = 80%), but when the pollution is heavy, the DPs of terrestrial aerosols are almost 20% lower than those of marine sources. These models can be directly used to characterize the hygroscopic characteristics of atmospheric aerosols in Qingdao at specific seasons or pollution levels for radiative transfer modeling, remote sensing, and so forth.

Atmospheric Aerosol Outbreak over Nicosia, Cyprus, in April 2019: Case Study

This paper aims to analyze the significant changes in atmospheric aerosol characteristics during the extreme aerosol outbreak event in April 2019 in the atmosphere over Cyprus in the Eastern Mediterranean. We study the aerosol optical depth (AOD), Ångström exponent (AE), single-scattering albedo, refractive index, size, and vertical distribution of aerosol particles during the event of intense aerosol advection in detail. For this purpose, we used the ground-based observations of the sun-photometer AERONET Nicosia station, lidar measurements, and back trajectories of air movements calculated using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT). To compare with background aerosol load conditions during the year, the available data of AOD and AE were used from the observations at the Nicosia AERONET site in the 2015–2022 period. On 23–25 April 2019, strong aerosol advection over Nicosia was detected according to lidar and sun-photometer observations. On 25 April 2019, the day with the largest aerosol contamination, the AOD value exceeded 0.9 at λ = 500 nm. Analysis of the optical and microphysical characteristics during the extreme event supported that the aerosol advection consists of mainly Saharan dust particles. This assumption was confirmed by the AOD versus AE variations, single-scattering albedo, refractive index, and size distribution retrievals, as well as lidar data and HYSPLIT backward trajectories, where air masses containing dust particles came mostly from North Africa. The analysis shows that the April 2019 event was one of the strongest aerosol surges that regularly take place in springtime in the atmosphere over Cyprus. The noticeable reduction in the effective radiative forcing caused by increasing aerosol amount during the aerosol dust outbreak was revealed.

Research on Lidar Network Observation of Aerosol and Pollution in Beijing 2022 Winter Olympics

During the Beijing Winter Olympics, three sets of aerosol lidar in different regions were used to conduct continuous observations to study the optical properties and vertical distribution characteristics of atmospheric aerosol. Based on the lidar data and sun photometer data, the accurate lidar ratio was determined to improve the inversion accuracy of the aerosol backscattering coefficient. The influence of meteorological conditions such as temperature, relative humidity, wind speed, and wind direction on the optical properties of aerosol were analyzed, and the type of aerosol was classified by the depolarization ratio of aerosol particles and CALIPSO data. Furthermore, the backward trajectory analysis, potential source contribution function (PSCF), and concentration weighted trajectories (CWT) were employed to explore the sources and transport mechanisms of pollutants. The analysis found that the extinction coefficient under the atmospheric boundary layer during the Winter Olympics had a spatial distribution pattern of high value in the southeast and low value in the northwest. The occurrence of aerosol pollution events is not only caused by local emissions, but is also related to regional transmission.

On-Orbit Autonomous Geometric Calibration of Directional Polarimetric Camera

The Directional Polarimetric Camera (DPC) carried by the Chinese GaoFen-5-02 (GF-5-02) satellite has the ability for multiangle, multispectral, and polarization detection and will play an important role in the inversion of atmospheric aerosol and cloud characteristics. To ensure the validity of the DPC on-orbit multiangle and multispectral polarization data, high-precision image registration and geolocation are vital. High-precision geometric model parameters are a prerequisite for on-orbit image registration and geolocation. Therefore, on the basis of the multiangle imaging characteristics of DPC, an on-orbit autonomous geometric calibration method without ground reference data is proposed. The method includes three steps: (1) preprocessing the original image of the DPC and the satellite attitude and orbit parameters; (2) scale-invariant feature transform (SIFT) algorithm to match homologous points between multiangle images; (3) optimization of geometric model parameters on-orbit using least square theory. To verify the effectiveness of the on-orbit autonomous geometric calibration method, the image registration performance and relative geolocation accuracy before and after DPC on-orbit geometric calibration were evaluated and analyzed using the SIFT algorithm and the coastline crossing method (CCM). The results show that the on-orbit autonomous geometric calibration effectively improves the DPC image registration and relative geolocation accuracy. After on-orbit calibration, the multiangle image registration accuracy is better than 1.530 km, the multispectral image registration accuracy is better than 0.650 km, and the relative geolocation accuracy is better than 1.275 km, all reaching the subpixel level (&lt;1.7 km).

Spatial distribution of PM2.5 chemical components during winter at five sites in Northeast Asia: High temporal resolution measurement study

The Center for Fine Particle Research Initiative in East Asia considering National Differences (FRIEND) project was launched in 2020 to characterize air pollution in Northeast Asia with effective collaboration. One of the goals of this study is to elucidate the spatiotemporal characteristics of atmospheric aerosols (e.g., PM2.5) in Northeast Asia. To achieve this objective, (1) the chemical speciation of fine particles was measured in high resolution, (2) the physical characteristics of fine particles were also elucidated, and (3) the gaseous and particulate components of the atmospheric aerosols were comprehensively monitored. The first field campaign was conducted from December 15, 2020, to January 15, 2021, and simultaneously monitored five key sites in Northeast Asia: Ulaanbaatar, Mongolia; Beijing, China; Seosan and Seoul, Republic of Korea (Korea); and Noto, Japan. The synoptic weather conditions mainly determined the periods of high PM2.5 mass concentration. During the first high-pollution event, the air over the Northeast Asian region was generally stagnant, and the inland wind speed over China, Korea, and Japan was very low. The PM2.5 mass concentration in Beijing, Seosan, and Seoul had increased simultaneously. Then, the prevailing westerlies in Northeast Asia caused the polluted air mass observed in Seoul to move to the background site in Noto. During the second high-pollution event, the Asian dust phenomenon occurred in the Gobi Desert and moved to all sites. Though the synoptic weather conditions largely determined the trend of the PM2.5 mass concentrations at the five sites, the levels of chemical components in both gaseous and particulate phases were different at each site, reflecting local emission and formation characteristics. Overall, the concentrations of air pollutants were highest in Ulaanbaatar; comparable in Beijing, Seoul, and Seosan and very low in Noto. A common characteristic of the five sites was the high organic aerosol (OA) proportion in fine particles. The chemical components that increased with the PM2.5 mass concentration were OA at Ulaanbaatar, OA and nitrate at Beijing and Seosan, nitrate at Seoul, and sulfate and OA at Noto. Further study directions for each site are discussed.

A Spatio-Temporal Weighted Filling Method for Missing AOD Values

Aerosol Optical Depth (AOD) is a key parameter in defining the characteristics of atmospheric aerosols, evaluating atmospheric pollution, and studying aerosol radiative climate effects. However, a large amount of the AOD data obtained by satellite remote sensing are missing due to cloud cover and other factors. To obtain AOD data with continuous distribution in space, this study considers the spatial and temporal correlation of AOD and proposes a spatio-temporal weighted filling method based on a sliding window to supply the missing AOD data blocks. The method uses the semivariogram and autocorrelation function to judge the spatial and temporal correlation of AOD and uses the AOD spatial autocorrelation threshold as the sliding window size, and then it builds a spatio-temporal weighted model for each window to fill in the missing values. We selected the area with full values for simulation. The results show that the accuracy of this method has been significantly improved compared with the mean filling method. The R2 reaches 0.751, the RMSE is 0.021, and the filling effect is smoother. Finally, this method was used to fill in the missing values of the MultiAngle Implementation of Atmospheric Correction (MAIAC) AOD in the Beijing–Tianjin–Hebei region in 2019, and AErosol RObotic NETwork (AERONET) AOD was used as the true value for testing. The results show that the filled AOD has a high correlation with AERONET AOD, the R2 is 0.785, and the RMSE is 0.120. A summary of the AOD values of the 13 cities in the Beijing–Tianjin–Hebei region shows that the values in the first and third quarters are higher than those in the second and fourth quarters, with the highest AOD value in March and the second highest in August; among the 13 cities, the AOD values in Chengde and Zhangjiakou are lower than those in the other cities.

Year-round observation of atmospheric inorganic aerosols in urban Beijing: Size distribution, source analysis, and reduction mechanism

To investigate particle characteristics and find an effective measure to control severe particle pollution, year-round observation of size-segregated inorganic aerosols was conducted in Beijing from January to December, 2016. The sampled atmospheric particles all presented bimodal size distribution at four pollution levels (clear, slight pollution, moderate pollution and severe pollution), and peak values appeared at the size range of 0.7-2.1 μm and >9.0 μm, respectively. As dominant particle compositions, NO3−, SO42−, and NH4+ in four pollution levels all showed significant peaks in fine mode, especially at the size range of 1.1-2.1 μm. Secondary inorganic aerosols accounted for about 67.6% (36.3% (secondary sulfates) + 31.3% (secondary nitrates)) of the total sources of fine particles in urban Beijing. Severe pollution of fine particles was mainly caused by the air masses transported from nearby western and southern areas, which are industrial and densely populated region, respectively. Sensitivity tests further revealed that the control measures focusing on ammonium emission reduction was the most effective for particle pollution mitigation, and fine particles all showed nonlinear responses after reducing ammonium, nitrate, and sulfate concentrations, with the fitting curves of y = -120.8x - 306.1x2 + 290.2x3, y = -43.5x - 67.8x2, and y = -25.8x - 110.4x2 + 7.6x3, respectively (y and x present fine particle mass variation (μg/m3) and concentration reduction ratio (CRR)/100 (dimensionless)). Overall, our study presents useful information for understanding the characteristics of atmospheric inorganic aerosols in urban Beijing, as well as offers policy makers with effective measure for mitigating particle pollution.

Simulation of the impact of the atmospheric weather state on the efficiency of functioning of solar thermal and power plants

THE PURPOSE. Determine the impact of the meteorological state of the atmosphere on the efficiency of the functioning of solar thermal and power plants. Modeling the molecular absorption of solar radiation by the atmosphere. Modeling the optical characteristics of the gaseous components of the atmosphere, atmospheric aerosol and clouds.METHODS. A method for numerical modeling of incoming solar radiation fluxes their functioning to determine the efficiency of solar thermal and power plants. The solar fluxes are calculated by stacking layers in a multi-stream approximation, taking into account the multi-tiered cloud cover and the probability of overlapping the sky with clouds. The absorption of radiation by the gaseous phase of the atmosphere is taken into account by the method of equivalent mass in an inhomogeneous atmosphere. The optical characteristics of the dispersed phase of the atmosphere are calculated using the Mie theory.RESULTS. An electronic database has been created on the optical characteristics of the gaseous components of the atmosphere, the optical characteristics of atmospheric aerosol and clouds. The effect of anthropogenic impact on the flux of solar radiation falling on the underlying surface is taken into account. The developed modeling takes into account the effect of humidity on the optical characteristics of atmospheric aerosol and its multicomponent composition, depending on the location of the power plant.CONCLUSION. The information necessary for numerical modeling of meteorological effects on the functioning of solar thermal and power plants is generalized. When calculating solar radiation fluxes, direct illumination of the light-receiving surface by solar radiation, scattered radiation by atmospheric aerosol and clouds are taken into account.

Impact of a sea breeze event on geochemical behavior of aerosols at a Mediterranean coast (Northern Tunisia)

The aim of this study is to identify the impact of a sea-land breeze circulation on the ventilation of air masses over the Mediterranean Tunisian coast (Boukornine area) during the summer period. Our results show the Mediterranean Sea has an important effect on the chemical characteristics of atmospheric aerosols by the advection of particles from the sea to the coastal site. Indeed, the daytime sea breeze as well the nighttime land breeze limit the ventilation of air masses by the redistribution of aerosols. Besides, it was found that higher concentrations of sodium, chlorine and sulfur over the examined area are associated with the sea-land breeze recirculation while the crustal constituents stay practically constant with some fluctuations due to local effect. The contribution of sea-breeze in Boukornine area was more important than those recorded in other sites in Tunisia. This study proves the high influence of topography which increases the effect of sea-breeze.

Statistical generalization of the characteristics of atmospheric aerosol over the White Sea (expeditions 2003-2021)

Statistical generalization of the characteristics of atmospheric aerosol over the White Sea (expeditions 2003-2021)