Chemical Composition Of Precipitation Research Articles

Economic and Industrial Development SignificantlyContribute to Acidity and Ionic Compositions of Rainwaterin China

To achieve a holistic understanding of the intricate interactions among human activities, atmospheric chemistry, and acid rain in China, a rigorous analysis of rainwater chemistry was made using a dataset comprising 2656 data points from 24 sites. The main cation and anion in the chemical composition of precipitation were Ca2+ and SO42− in China, with an average concentration of 169.9 μeq/L and 135.4 μeq/L, respectively. Acid rain generally occurs in southern cities such as Shenzhen, Guangzhou, Zhuhai, Xiamen, and Chongqing. There were evident regional disparities in acidity and ion concentrations in rainwater, with an increase in acidity and a decrease in ion concentrations from north to south across China. Utilizing positive matrix factorization, the study found that NH4+, SO42−, and NO3− mainly originated from anthropogenic sources such as fossil fuel combustion, vehicle exhaust emissions, agricultural fertilization, and industrial emissions (as reflected by F3 and F4). Ca2+ mainly stems from crustal factors, including industrial dust and natural crust (as represented by F1 and F4). Na+ and Cl− were traceable from marine sources (as reflected by F5), while Mg2+ originated from crust origin (as presented by F1). K+ was mainly derived from a mixed source of crust, marine, and biomass burning (as indicated by F2 and F3). The correlation analyses showed that SO42− and NO3− showed significant correlations with GDP and population. F− was associated with wastewater, which may be linked to the production of brick and tiles from clay with high fluoride contents. The pH was negatively related to industrial wastewater. Long-term analysis of precipitation chemistry in four cities suggested a clear decrease in the proportion of SO42− but a considerable increase in the proportion of NO3− in anions in metropolitans of Shanghai and Chongqing due to the environmental measures that targeted reducing sulfur dioxide (SO2) emissions and increase of vehicles. This showed that pollution control strategies had an impact on precipitation ion concentrations. These results can conclude that economic and industrial growth, which will increase energy consumption, utilization of coal combustion, and a subsequent rise in pollutant emissions, can contribute to the change in the chemical compositions of rainwater and the exacerbation of acid rain.

Precipitation characteristics and growth mechanism of Fe and Cr from liquid lead-bismuth eutectic by quenching in liquid nitrogen

The compatibility of structural steels with liquid lead-bismuth eutectic (LBE) restricts the development of the lead-cooled fast reactor (LFR) and the accelerator driven sub-critical (ADS) system. During the reactor operation, alloying elements in steel can dissolve into LBE. The dissolved alloying elements could precipitate in cold parts of the reactor due to the decrease in solubility, which can cause pipe clogging and worsen heat transfer. Therefore, it is necessary to study their precipitation characteristics to provide a reference for the filtration process. In this paper, Fe, Cr, and a mixture of Fe and Cr were added to liquid LBE at 1173 K and quenched in liquid nitrogen to study their precipitation characteristics. The scanning electron microscope (SEM) and field-emission scanning electron microscope (FESEM) were used to analyze the morphology, and the phase structure was identified by an X-ray diffractometer. The chemical compositions of precipitates were analyzed by an energy dispersive spectrometer (EDS, Esprit Compact, Bruker) and an electron probe microanalyzer (EPMA, EPMA-8050 G, Shimadzu). The solid-liquid interface structure and growth mechanism of precipitates were also discussed. The difference in growth mechanisms resulted in various morphologies for the precipitates. There were three morphologies of precipitates: faceted dendrite, polyhedron (cube, octahedron, and hopper), and seaweed dendrite. All the precipitates in LBE have a faceted growth character except the seaweed dendrites, irrespective of their morphology. The growth of Fe, Cr, and Cr-Fe faceted dendrites originated from continuous growth followed by lateral growth. On the contrary, the cubic and octahedral precipitates were controlled by the spiral growth mechanism, and the growth mechanism of hopper crystals was two-dimensional nucleation. The formation of seaweed dendrites was caused by a strong local undercooling of nonfaceted dendrites.

Nitrogen and sulfur compounds in ambient air and in wet atmospheric deposition at Mexico city metropolitan area

Mexico City Metropolitan Area (MCMA), one of the most populous cities in the world, has historically represented a challenge in terms of air pollution. Particulates and sulfur dioxide.(SO2) were identified as the main atmospheric pollutants three decades ago. In order to reduce emissions of these pollutants, replacing of fuel oil by natural gas in power plants was carried out in the late 1980s. This strategy resulted in the reduction of ambient air concentrations of both pollutants. SO2 no longer exceeds its ambient air quality standard; however, acid rain remains a significant issue, with sulfate remaining as the principal component in the wet atmospheric deposition.In this study, spatial and temporal variations in the chemical composition of precipitation (sulfate and nitrate ions, and pH) were obtained weekly at 16 sampling stations, as well as atmospheric SO2 and nitrogen oxides (NOx) from an air quality monitoring network from 2003 to 2018 in the MCMA. Some indicators were applied to evaluate wet atmospheric deposition: SO42−/NO3− and NH4+/NO3− ratios, fractional acidity as well as neutralization factors.SO2 ambient air concentrations have decreased from 2003 to 2018 by more than 70%, while NOx has decreased by 20%. The SO2/NOx ratio has declined about 60%, indicating more effective strategies in reducing SO2 than for NOx emissions. The NOx emission sources are more diverse than for SO2, and NOx has more complex mechanisms of atmospheric deposition and photochemistry.The pH values of the samples at the stations located in the south were more acidic than the samples for the stations in the north. This result is in line with meteorological conditions, where prevailing winds blow from north to south, as well as emission sources located in the north sector, both inside and outside MCMA. For SO42−/NO3− ratio, all sampling sites present current values in the same magnitude order, around 1.4, which is higher compared with urban sites in USA. The 2018 NH4+/NO3− ratio was 1.98 for the southern sampling site, while all northern sampling sites were approximately 2.28. These results are on the same order that urban sites in USA. It was concluded that ammonium was a very important neutralizing agent of pH within the MCMA precipitation.It is recommended to apply strategies for the emissions reduction of acid rain precursors in external sources to the North the MCMA, and to establish a Network for Urban Atmospheric Nitrogen Chemistry.

Chemical Compositions of Rainfall Water in Nyingchi City, Tibet

Understanding precipitation chemistry is highlighted as important worldwide due to its close relationship with air quality and impacts on ecosystems. However, the chemical composition of precipitation is limited in Tibet, where alpine ecosystems are sensitive to global change. Here, rainwater samples were collected in Nyingchi city from January 2021 to December 2021, and a total of 44 samples were obtained. Major ions (NO3−, NH4+, Cl−, SO42−, Na+, K+, Ca2+ and Mg2+) were analyzed. Results showed that the predominant ions in the precipitation were Ca2+, Na+, SO42−, and Cl−. Precipitation was mainly concentrated in summer, accounting for 65.2% of all samples collected during the monitoring period. As a result, ion deposition fluxes were mainly concentrated in summer, accounting for 55%, 53%, 84%, 82%, 61%, 63%, 75.8%, and 37.8% of the annual Ca2+, K+, Mg2+, Na+, NH4+, Cl−, SO42−, and NO3−, respectively. Backward trajectory analysis revealed that airmasses were mainly from the southern direction, but the sources varied widely. In addition, Na+ and Cl− ions were dominated by the sea source fraction; the ions of Ca2+ and K+ were dominated by crustal fraction sources. The NH4+ and NO3− ions were mainly influenced by local pollution. However, SO42− was mainly from long distance transports. Our results suggest that ions abundance was varied largely in different direction airmasses in southeast Tibet. Considering that ion deposition fluxes were mainly concentrated in the summer and the airmasses were mainly from the southern direction in this season, the pollutants from the southern direction the environmental effects of those ions should be given more attention in the future.

Use of sewage sludge in concrete industry

Introduction. The article deals with the actual problem of disposal of industrial waste (sewage sludge). According to the literature data, possible directions of the use of sewage sludge in the production of building materials are identified and considered. Special attention is paid to the proposed variant of systematization of materials, which is based on the dependence of the aggregate state of the sediment on the type of building material. It is proposed to use sewage sludge as a complex additive to improve rheological properties at all stages of heavy concrete hardening.Methods and materials. Studies of the basic properties of raw materials and concrete based on them were determined using standard methods and the requirements of national standards. The material and chemical composition of the sediments, their physical and mechanical characteristics were determined on the basis of the laboratory of the plant of chemical concentrates (Novosibirsk).Results. As a result of the experimental work, the optimal percentage of sewage sludge in the composition of heavy concrete was determined, as well as the ratio of the chemical modifying additive, the optimal composition of concrete was investigated.Conclusion. As a result of the experimental work, the influence of the introduction of sewage sludge modified with plasticizing additives into the concrete composition was established. It has been established that sewage sludge is advisable to use in heavy concrete as a corrective additive without reducing the strength characteristics. In further studies, it is planned to solve the problems of structure formation and study of the interface between the phases of sewage sludge in the composition of concrete; to investigate the relationship between the chemical composition of precipitation and the physical and mechanical properties of a building material.

Source contributions in precipitation chemistry and analysis of atmospheric nitrogen deposition in a Sahelian dry savanna site in West Africa

Experimental data on precipitation chemistry were collected at a semi-arid savanna in Senegal (Dahra) in 2013, 2014 and 2017. The chemical composition of precipitation was analyzed for inorganic and organic ions, using ionic chromatography. The pH values of precipitation range from 4.50 to 8.50 with 89% of the samples having basic pH. The composition of precipitation was controlled by four source contributions: marine, terrigenous, biogenic, and organic acids emissions from vegetation. The terrigenous contribution was the highest accounting for 42% of the total annual Volume Weighted Mean ionic concentrations, due to the proximity of the Saharan desert, followed by the marine source representing 36%, due to the location of Dahra close to the Atlantic Ocean. Nitrogenous (N) contribution represents 16% of the mean annual total ionic charge, from biogenic sources and livestock crossing the site all year round. Finally, the lowest contribution is from organic acidity (5%), due to the low density of vegetation especially during the dry season. Wet deposition fluxes in Dahra for all compounds show larger values than at other Sahelian savanna sites. Dry N deposition in Dahra was also estimated by inferential method using gas concentration measurements and modeled dry deposition velocities. The total N deposition fluxes (wet plus dry) range from 3.80 to 4.81 kgN ha−1 yr−1, comparable to fluxes at other semi-arid savannas in Niger and Mali. Wet deposition contributed with 37–53% of the total N flux, suggesting that wet N deposition is equally important to dry deposition fluxes for direct N loading to savanna ecosystems in the Sahel, with a large contribution of reduced compounds. This study shows that Dahra presents a precipitation chemistry composition with characteristics close to those from other Sahelian sites, with however the specificity of being more influenced by the proximity of the Atlantic ocean and the presence of livestock year round.

Long-Term Temporal Changes of Precipitation Quality in Slovak Mountain Forests

The paper is focused on the evaluation of long-term changes in the chemical composition of precipitation in the mountain forests of Slovakia. Two stations with long-term measurements of precipitation quality were selected, namely the station of the EMEP (European Monitoring and Evaluation Programme) network Chopok (2008 m a.s.l.) and the station of the ICP Forests (International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests) network Poľana-Hukavský grúň (850 m a.s.l.). All basic chemical components were analyzed, namely sulfur (S-SO4), nitrogen (N-NH4, N-NO3), and base cations (Ca, Mg, and K) contained in precipitation. The time changes of the individual components were statistically evaluated by the Mann–Kendall test and Kruskal–Wallis test. The results showed significant declining trends for almost all components, which can significantly affect element cycles in mountain forest ecosystems. The evaluated forty one-year period (1987 to 2018) is characterized by significant changes in the precipitation regime in Slovakia and the obtained results indicate possible directions in which the quantity and quality of precipitation in the mountainous areas of Slovakia will develop with ongoing climate change.

Isotopic composition and hydrogeochemistry of a periglacial Andean catchment and its relevance in the knowledge of water resources in mountainous areas

ABSTRACT Glacial and periglacial basins contain the largest reserves of fresh water in the world. These areas are extremely sensitive to global warming and climate change. The dry Andes of South America are characterized by large periglacial areas. This study focuses on the water isotopic composition and hydrochemistry of a typical periglacial environment of the Andes, in the Vallecitos catchment (2400–5500 m a.s.l.), Cordillera Frontal, Argentina. Detailed fieldwork was conducted between 2013 and 2017 with 240 samples collected for major ions and physicochemical parameters, and 67 samples analysed for 2H and 18O. The chemical composition of precipitation is typical Ca-HCO3, while streams and groundwaters are Ca-MgSO4 type. The isotope content of precipitation shows a wide dispersion. The snow samples are in general more depleted than the rainfall. Some springs vary their composition seasonally, associated to the melting of perennial snow patches. In general, all samples from the upper basin present depleted isotope contents related to recharge at higher altitudes, whereas samples from the lower basin show more enriched values. Intermediate compositions reflect the melting of snow and degrading ice-rich permafrost. These results will give a better understanding of the dynamics of water to manage water resources.

Biogeochemical Migration of Elements within the Lake Watershed of a Reference Site (Valdai Upland)

This study concerns the distribution of elements in the atmospheric precipitation–throughfall–soil water system of the Gusinoe Lake watershed in the Valdai Upland. The chemical compositions of precipitation, throughfall, and soil water, as well as soils, are determined. Element budgets are calculated in the soil profile studied for the summer–autumn period. Estimates are made of the soil enrichment in elements and the intensity of element migration in soil water.

Chemical Characteristics and Ionic Sources of Precipitation in the Source Region of the Yangtze River

Using 64 precipitation samples collected from June to September 2013 in the Dongkemadi Basin in the source region of the Yangtze River, the pH, conductivity, and main ionic concentration characteristics of precipitation were analyzed. The main ionic sources of precipitation and their relationships with atmospheric circulation were examined using factor analysis, correlation analysis, enrichment factor analysis, and backward trajectory analysis. The results showed that the range of precipitation pH values varied from 5.26 to 9.25 with a weighted average of 6.70, and conductivity ranged from 0.23 to 28.70 μS·cm-1 with a weighted average of 3.45 μS·cm-1. The conductivity of precipitation was lower than for the Mt. Waliguan basin (China Global Atmosphere Watch baseline observatory). The total ionic concentrations in the precipitation ranged from 7.0 to 376.9 μeq·L-1 with a weighted average of 40.8 μeq·L-1. The ranked order of ionic concentrations was HCO3- > NH4+ > Ca2+ > NO3- > SO42- > Na+ > Cl- > K+ > Mg2+. HCO3-, NH4+,Ca2+, and NO3- were the dominant ions, which accounted for 74.75% of the total ionic concentration. Fractional acidity (FA) analysis showed that 97.8% of the precipitation acidity was neutralized by alkaline constituents. Neutral factor (NF) analysis indicated that NH4+ and Ca2+ were the dominant neutralization constituents in the precipitation. The precipitation ions in this study area were mainly derived from terrestrial material, while input from marine sources was relatively low. Backward trajectory analysis revealed that the total ionic concentrations varied significantly between the different sources, which followed the order of local sources>westerly sources>monsoon sources. This indicates that different atmospheric circulation conditions and air mass sources have a significant influence on the chemical composition of precipitation in this area. To some extent, the chemical characteristics of precipitation could reflect the air quality and background values for remote areas due to the limited effect of human activities. The results of this study provide a scientific basis for the protection of water quality and the assessment of the impact of human activities on the atmospheric environment in the source region of the Yangtze River.

Quantification of APT physical limitations on chemical composition of precipitates in Fe–Cr alloys

Among the different nano-features at the origin of embrittlement of Fe–Cr alloys and steels, α′ precipitates play a major role in alloys with Cr content higher than about 10at.%. If Atom Probe Tomography (APT) is recognized as an efficient technique for characterizing α′ precipitates, discussions remain on its ability to measure the actual composition of small particles. Two APT limitations are at the origin of these discussions: its lateral resolution (and on a smaller scale the depth resolution) and local magnification effects due to the difference in field evaporations between the matrix and the particles. In this study, the impacts of these two limitations are quantified for the first time using numerical approaches and an analytical model. This will provide an overview of the interpretation for the α’ particles chemical composition experimentally measured by APT.The results show that: (i) the major effect of local magnification is ion focussing with no mixing in the core of the particles for particle radius larger than 1 nm, (ii) lateral resolution is the main contributor to the composition bias. Depending on the lateral resolution, the core of the small particles may be diluted by matrix atoms but the dilution does not exceed 5.2 at.%. The extent of the decrease in measured Cr concentration of the particles depends on the Cr concentration difference between particles and the surrounding matrix.

The chemical composition of precipitation in Ukraine and its potential impact on the environment and water bodies

This article provides characteristic of the chemical composition of atmospheric precipitation on the territory of Ukraine and its potential impact on the environment and water bodies. In Ukraine, the rainfall is 650 mm/year in the northwest of the country (mixed forests), up to 300 mm/year in the south (steppe zone), in the Ukrainian Carpathians - up to 1,600 mm/year. Acidity of atmospheric precipitation (pH) on the territory of Ukraine according to monitoring meteorological stations is 5.9-6.3. Minimum values of mineralization of atmospheric precipitation are observed in a zone of mixed forests in the north of the country. In particular, according to the weather station of Teteriv, the mineralization of atmospheric precipitation is 27.0 mg/l. In forest-steppe and steppe zones, this rate gradually increases to 35-45 mg/l, reaching a maximum in the steppe zone at the Askania-Nova meteorological station (82.4 mg/l). In the chemical composition of atmospheric precipitation, anion predominates sulfates, and among cations - magnesium. Anthropogenic component of the total mineralization of atmospheric precipitation, calculated for the first time on the territory of Ukraine (meteorological station Kobelyaki) by comparison with the regional natural background, is 69%. Concentration of sulfate ions (8-24 mg/l) in atmospheric precipitation on the territory of Ukraine shows a high level of pollution with sulfur, which corresponds to IV-V levels o environmental pollution. It is noted that with increasing concentrations of sulfates in atmospheric precipitation a tendency towards a decrease in the pH in the water of Svityaz Lake is projected. Current research shows that at high concentrations of sulfates in atmospheric precipitation, the risk of falling individual rains with low pH (so-called acid rains) increases. Waters of high concentration of organic matter and low mineralization of water are widely distributed on the territory of Ukraine (catchments of Polissya and the Carpathian region): up to 100 mg/l in the meadows and up to 30 mg/l in the flood period. Often, the pH of water in them is 6-6.5 and precipitation of acidic precipitation can significantly affect their hydroecological state. The obtained results on the influence of chemical composition of atmospheric precipitation on water objects have a diagnostic character. For more specific results, special synchronized studies of the chemical composition of the water of experimental water reservoirs with sampling ofatmospheric precipitation are required.

Chemical composition of precipitation in Shenzhen, a coastal mega-city in South China: Influence of urbanization and anthropogenic activities on acidity and ionic composition

Rainwater samples from Shenzhen in south China were collected over the period of a year, and the chemical compositions were measured with the main purpose of understanding the acidification of rainwater and the controlling factors. The pH value of precipitation ranged from 3.72 to 6.77, with a volume-weighted mean (VWM) value of 4.29, and the acid rain frequency was 97%. The VWM concentrations of anions and cations followed the order of SO42− > Cl− > NO3− and Na+ > Ca2+ > NH4+ > Mg2+ > K+, respectively. Air mass back-trajectory and positive matrix factorization analyses indicated that sources of ions in rainwater were mainly from sea salt, soil dust and anthropogenic activities. Compared with other areas in China, the rainwater of Shenzhen has the lowest values of the NP/AP, ∆pH and NF values of Ca2+ and NH4+, indicating that the lack of the capacity for neutralization could be the main reason for the severe acid rain problem. It is noteworthy that the rain acidification tendency is obvious, and the pH value has reduced by 1.0 units since the 1980s. Based on a comparison of the chemical compositions of the rainwater from different historical periods, the NO3− concentration was found to have increased consistently, whereas the NH4+ concentration maintained a decreasing trend since 1980. On the other hand, the nss-SO42− and nss-Ca2+ concentrations increased after 1980 and then decreased after 1994. Meanwhile, the decreasing pH was accompanied by a decreasing NP/AP ratio. These results suggest that the changes in human activities at different stages of urban development can lead to a synergistic change in the chemical characteristics of precipitation. Both an increase in the acidic species emissions (especially NOX) due to rapid economic development and a decrease in the alkaline ions concentration due to urbanization have resulted in the rain acidification tendency in Shenzhen.

Influence of peat fires on the rainwater chemistry in intra-mountain basins with specific atmospheric circulations (Eastern Carpathians, Romania)

A comprehensive study on the chemical composition of precipitation, the influence of peat fires and their relations with atmospheric circulation was conducted in the year of 2012, in two intra-mountain basins, the Ciuc basin (CB) and the Giurgeu basin (GB), Eastern Carpathians, Romania. Atmospheric circulation types showed the presence of a westerly anticyclonic circulation, characterized by a strong development of the Azores High to the northern Atlantic, contributing to the appearance of peat-fires. Using ROCADA daily gridded climatic datasets, the maximum and minimum daily temperatures were extracted, showing deviation from 2 °C to 6 °C in the studied year against the multiannual mean for the 1981–2016 period. Rainwater samples were analyzed for pH, major anions and cations; HCO3− concentrations were calculated based on the empirical relationship between pH and HCO3−. The results showed that 45.16% and 54.55% of precipitation had pH > 7.0 at CB and GB, respectively. NH3, NH4+ and Ca2+ are the main neutralizing agents. The significant correlation between SO42− and NH4+ (r = 0.711 – CB; r = 0.736 – GB) indicated neutralization by NH3 in the forms of (NH4)2SO4 and NH4HSO4. Positive regression coefficient between the sum of (H+ + [NH4+] + [Ca2+]) and the sum of ([nss − SO42−] + [NO3−]) (r = 0.855 – CB; r = 0.796 – GB), showed that acid neutralization was primarily brought by NH4+ and/or CaCO3. Using Na as an indicator of marine origin, the proportions of sea salt and non-sea-salt were estimated from elemental ratios. According to correlation analysis and PCA, main acidic ions (SO42− and NO3−) and NH4+ were mainly derived from anthropogenic activities (biomass burning, peat fires, fertilization), while Ca2+ and Mg2+ originated from terrestrial sources. The behavior of gaseous pollutants and smoke distribution resulted from peat fires were deciphered using the HYSPLIT model in a case study.

Properties and Structure of Deposited Nanocrystalline Coatings in Relation to Selected Construction Materials Resistant to Abrasive Wear.

Presented in this work are the properties and structure characteristics of MMA (Manual Metal Arc) deposited nanocrystalline coatings (Fe-Cr-Nb-B) applied to an iron nanoalloy matrix on an S355N steel substrate in relation to selected construction materials resistant to abrasive wear currently used in industry. The obtained overlay welds were subjected to macro and microscopic metallographic examinations; grain size was determined by X-ray diffraction (XRD), and chemical composition of precipitates was determined by energy-dispersive X-ray spectroscopy (EDS) during scanning electron microscopy (SEM). The size of the crystalline grains of the Fe-Cr-Nb-B nanocrystalline microstructure was analyzed using an Xpert PRO X-ray diffractometer. Analysis of the test results of the obtained layers of arc-welded Fe-Cr-Nb-B-type alloy confirmed that the obtained layers are made of crystallites with a size of 20 nm, which classifies these layers as nanocrystalline. The obtained nanocrystalline coatings were assessed by hardness and with the use of metal-mineral abrasion testing. The results of the coatings’ properties tests were compared to HARDOX 400 alloy steel.

Phase formation in the system Zn(VO3)2–HCl–VOCl2–H2O

The phase and chemical compositions of precipitates formed in the system Zn(VO3)2–HCl–VOCl2–H2O at pH 1−3, molar ratio V4+: V5+ = 0.1−9, and 80°C were studied. It was shown that, within the range 0.4 ≤ V4+: V5+ ≤ 9, zinc vanadate with vanadium in a mixed oxidation state forms with the general formula ZnxV4+ yV5+ 2-yO5 ∙ nH2O (0.005 ≤ x ≤ 0.1, 0.05 ≤ y ≤ 0.3, n = 0.5−1.2). Vanadate ZnxV2O5 ∙ nH2O with the maximum tetravalent vanadium content (y = 0.30) was produced within the ratio range V4+: V5+ = 1.5−9.0. Investigation of the kinetics of the formation of ZnxV2O5 ∙ nH2O at pH 3 determined that tetravalent vanadium ions VO2+ activate the formation of zinc vanadate, and its precipitation is described by a second-order reaction. It was demonstrated that, under hydrothermal conditions at pH 3 and 180°C, zinc decavanadate in the presence of VOCl2 can be used as a precursor for producing V3O7 ∙ H2O nanorods 50–100 nm in diameter.

Chemical composition of Russian Arctic precipitation in 2007-2015

The results of observations of the chemical composition of precipitation in the Russian Arctic in 2007-2015 are summarized including the data from NP-35 drifting ice station obtained in 2007-2008 in the framework of the joint program of Arctic and Antarctic Research Institute and Voeikov Main Geophysical Observatory. The qualitative and quantitative difference in the chemical composition of precipitation in the Atlantic, Siberian, and Pacific sectors of the Russian Arctic is revealed. It is found that the concentration of microelements (heavy metals) in precipitation at NP-35 ice station did not exceed 12% of total ions at the lowest mineralization. The comparative analysis is presented of the concentration of sulfate ions in precipitation in Norilsk and at NP-35 ice stations.

Impact of anthropogenic and natural processes on the chemical compositions of precipitation at a rapidly urbanized city in Northwest China

In this study, the chemical composition of precipitation was applied as an indicator to study the influence of urbanization on the atmosphere in Qilian County, a northwest city in China. The results showed that the annual mean pH calculated from the concentration of H+ was 7.35 due to alkaline ion neutralization, and Ca2+ had the largest contribution. Ca2+ and SO42− were the most abundant ions, accounting for 45 and 17%, respectively, of the total ion mass. The correlation coefficient between SO42− and NO3− reaching 0.85 in the urban area indicated the same source. The highest concentration of sulfate in spring was probably related to the strong wind in Northwest China, while the concentration of nitrate was the highest in winter suggesting that most of the nitrate originated from coal combustion, not vehicle emission. The application of factor and cluster analysis indicated that 38.43% of the SO42− and 16.97% of the NO3− in Qilian County were from crustal sources, while 61.5% of the SO42− and 83.03% of the NO3− originated from the human activities. The back trajectory analysis indicated that the pollution emitted from the surrounding areas also made a great contribution to the local atmospheric quality. Thus the communication and cooperation mechanisms with surrounding cities and improvement of energy consumption efficiency should be strengthened in the next few years.

Major impact of volcanic gases on the chemical composition of precipitation in Iceland during the 2014–2015 Holuhraun eruption

AbstractThe Holuhraun eruption in 2014–2015 was the largest in Iceland for more than 200 years. It resulted in emissions of large quantities of volcanic gases into the atmosphere (11 megaton (Mt) SO2, 0.1 Mt HCl, and 0.05 Mt HF). During the eruption the volcanic gases had major effects on F, SO4 and to a lesser extent Cl concentrations in precipitaxtion throughout Iceland, effects not observed in recent decades. The concentrations of F, Cl, and SO4 (n = 705) reached values of 444 µm 12,270 µm, and 17,324 µm during the eruption and were on average ~20 times higher for F and SO4 and much lower for Cl compared to preeruption times. The concentrations of major cations (Si, Na, K, Ca, Mg, Al, and Fe) (n = 151) in the precipitation were taken as having originated from seawater spray and dissolution of rock dust and aerosol. Based on the mixing model developed here, it is demonstrated that the source of the enrichment of F and SO4 was indeed the volcanic gas emissions with >60–100 mol % of SO4 and F in the precipitation originated from volcanic gas, whereas the Cl originated mostly from seawater spray, making the volcanic gas input of Cl relatively less important than for F and SO4. The results showed that large volcanic eruptions can have major effects on atmospheric chemistry and impact the composition of precipitation.

Chemical composition of precipitation and snow cover in the Primorsky krai

The chemical composition ofprecipitation from May 2012 to March 2013 and snow cover in the south of the Primorsky krai are studied. The measured parameters are pH and the concentration of principal ions, dissolved organic carbon, silicon, and metals in the samples of precipitation and snow cover taken in Vladivostok and in the background area of the Sikhote-Alin mountain range. Data from Primorskaya, Ternei, and Sadgorod stations are presented for comparison.