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Seyhi, Brahima, Patrick Droguil, Géraldo Buelna, Jean-François Blais, and Marc Heran. "État actuel des connaissances des procédés de bioréacteur à membrane pour le traitement et la réutilisation des eaux usées industrielles et urbaines." Revue des sciences de l’eau 24, no. 3 (November 28, 2011): 283–310. http://dx.doi.org/10.7202/1006478ar.
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Les effluents issus des stations d’épuration des eaux usées industrielles et municipales contiennent des quantités non négligeables de polluants organiques, inorganiques et microbiens, qui sont rejetés dans l’environnement par voie directe, ou en suivant la filière de réutilisation (irrigation ou arrosage, etc.). Ces eaux résiduaires constituent l’une des principales sources de contamination des eaux de surface et souterraines (augmentation de la demande chimique en oxygène (DCO), coloration et eutrophisation des cours d’eau, etc.). Dans l’optique de palier le déficit croissant des ressources en eau destinées à la consommation humaine, ces eaux résiduaires sont de plus en plus soumises à des traitements poussés en vue d’une réutilisation. Cette réutilisation doit toujours être réalisée dans l’objectif de fournir une eau présentant, en continu, une qualité spécifique liée à l’usage attendu (eau de production, eau de lavage, eau de refroidissement, eau d’irrigation ou d’arrosage, etc.). Les procédés conventionnels peuvent s’avérer non adaptés, notamment par leur manque de fiabilité dans la qualité des eaux traitées et le risque encouru de contamination microbiologique. Pour faire face à cette importante problématique, les techniques membranaires, notamment les bioréacteurs à membrane (BRM), peuvent constituer une avenue potentielle de traitement et de réutilisation de ces effluents. L’intérêt de ces procédés réside dans leur aspect non polluant, leur facilité d’automatisation et leur capacité à éliminer simultanément les différents polluants en une seule étape de traitement. Ces technologies offrent la possibilité de clarifier et de désinfecter simultanément les eaux sans risque de formation de composés organo-halogénés. Dans cet article, les BRM sont situés par rapport aux techniques conventionnelles de traitement biologique d’effluents. Par la suite, un accent particulier est mis sur la présentation des connaissances actuelles concernant les principes de base des BRM, les critères d’application et les conditions d’opération qui influencent les performances de ces technologies. Les développements récents portant sur la modélisation mathématique de fonctionnement et de colmatage de ces modules sont également présentés. Finalement, les applications industrielles et les coûts d’implantation et d’opération de ces technologies sont brièvement discutés.
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Cvetanović, Sveta. "Overview of nitrogen oxide reactions during fossil fuel combustion in the atmosphere." Safety Engineering 10, no. 2 (2020): 103–8. http://dx.doi.org/10.5937/se2002103c.
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This paper discusses the reactions of formation and decomposition of nitrogen oxides during fossil fuel combustion and in the atmosphere. Information about the chemical processes of pollutant formation and decomposition is the basis for the development of theoretical models of pollutant emissions. The information also provides a clearer picture about the primary factors influencing emissions. Nitrogen oxides are pollutants that damage human health, living and nonliving nature, and material property.
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Nitoi, Ines, Lucian Alexandru Constantin, Ionut Cristea, and Mirela Alina Constantin. "ADVANCED OXIDATION PROCESSES (AOPS) ALTERNATIVE METHODS FOR DEGRADATION OF TOXIC POLLUTANTS FROM WASTEWATER." Romanian Journal of Ecology & Environmental Chemistry 1, no. 1 (September 20, 2019): 40–54. http://dx.doi.org/10.21698/rjeec.2019.105.
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The degradation of some toxic pollutants like chlorobenzenes, nitrobenzene and 4-chloroaniline in various advanced oxidation system such as: UV/ H2O2, UV-VIS/Fe-TiO2 and UV-VIS/TiO2/ H2O2 were studied. The influence of working conditions (pH0, H2O2 dose, photocatalyst dose, pollutant initial concentration and irradiation time) on pollutant degradation rate constant and efficiency were investigated. For any studied advanced oxidation systems, pollutant degradation followed a pseudo first order kinetics. The degradation pathway of chlorinated and nitro aromatic pollutants includes initial •OH radicals attack to aromatic ring with hydroxylated intermediates formation, followed by their step by step oxidation up to carboxylic acids. Inorganic ions like Cl-, NO3-, NH4+ are also formed as mineralization products.
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El Azzi, Desiree, François Laurent, Vincent Roussiez, Lei Chou, Maritxu Guiresse, and Jean-Luc Probst. "Adsorption of Aclonifen, Alachlor, Cd and Cu onto Natural River Suspended Matter in the Context of Multi-Pollutions: Influence of Contaminant Co-Presence and Order of Input into the Aqueous Solution." Water 10, no. 9 (September 11, 2018): 1222. http://dx.doi.org/10.3390/w10091222.
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In the environment, a pollutant is rarely present alone, and other contaminants can influence its fate. To investigate the influence of the presence of other pollutants on the sorption of pesticides and trace metals (TM), the adsorption of Aclonifen, alachlor, Cd and Cu onto suspended particulate matter (SPM) was studied. SPM was isolated during the flood event of May 2010 in the Save agricultural watershed of SW France. Adsorption equilibrium was reached after 2 h of contact with SPM for pesticides and 24 h for TM. To simulate natural conditions, the SPM load allowing a maximum adsorption of pollutants was set at 1 g L−1 and the concentration of pollutants at 10 μg L−1. These factors being established, the co-presence experiments showed that most contaminants were influenced by the presence of other pollutant(s) in the water, trace metals to a lesser extent than pesticides. The mutual influence can be either competition for the same adsorption sites or formation of new complexes between pollutants. These phenomena can modify the adsorption capacities of each pollutant. The order of introduction into the aqueous solution also influenced the amount of adsorption of pollutants onto SPM. These results open new perspectives on the fate of pollutants.
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Błaś, Marek, Katarzyna Cichała-Kamrowska, Mieczysław Sobik, Żaneta Polkowska, and Jacek Namieśnik. "Conditions controlling atmospheric pollutant deposition via snowpack." Environmental Reviews 18, NA (December 2010): 87–114. http://dx.doi.org/10.1139/a10-003.
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Solid precipitation represents a potentially important addition to other measures of deposition. However, an accurate estimate of snowfall amount and pollutant loading is not a trivial matter. There are obvious distinctions between regular precipitation collection and snowpack sampling that represent the cumulative chemistry of bulk deposition. The main goal is to show the most important processes and factors that may influence the rate and magnitude of pollutants deposition affected by the snowfall and snow cover: atmospheric pollutant enhancement of snowfall, pollutants deposition at snow cover surface, drifting and blowing snow, formation of the snow cover and its internal changes, as well as pollutants flow through the snowpack. These phenomena lead to continuous changes in the chemistry of the snow cover and the deposition calculated on the basis of pollutants concentrations in daily portions of atmospheric precipitation. The real deposition released from snowpack is strictly related to the number and depth of thaw episodes. If the amount of stored pollutants is large, first portions of ablation water flushing from the snowpack can carry the load of pollutants, and potentially affecting the environment in a detrimental way. Igneous bedrock is especially sensitive to acidic ions because of its low buffering capacity.
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Meintrup, David, and Chang Woon Nam. "Shadow Market Area for Air Pollutants." Environment and Planning B: Planning and Design 36, no. 4 (January 1, 2009): 664–81. http://dx.doi.org/10.1068/b34053.
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This study identifies the shadow market area of air pollutants on the basis of the Gaussian plume model. Since pollutants are dispersed by wind, transport costs are irrelevant in its formation. Pollutant distribution on the ground level has an asymmetric bell shape in the wind direction. In addition to the linear functions, the exponential and quadratic shadow price functions are considered for the compensation of a health hazard to consumers, where the strict liability in the framework of the Coase theorem applies. The shadow market area for pollutants is shell shaped. This specific characteristic has an implication for market boundaries between polluters and their location decisions.
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Song, Xia, Nana Nyarko Mensah, Yuting Wen, Jingling Zhu, Zhongxing Zhang, Wui Siew Tan, Xinwei Chen, and Jun Li. "β-Cyclodextrin-Polyacrylamide Hydrogel for Removal of Organic Micropollutants from Water." Molecules 26, no. 16 (August 19, 2021): 5031. http://dx.doi.org/10.3390/molecules26165031.
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Water pollution by various toxic substances remains a serious environmental problem, especially the occurrence of organic micropollutants including endocrine disruptors, pharmaceutical pollutants and naphthol pollutants. Adsorption process has been an effective method for pollutant removal in wastewater treatment. However, the thermal regeneration process for the most widely used activated carbon is costly and energy-consuming. Therefore, there has been an increasing need to develop alternative low-cost and effective adsorption materials for pollutant removal. Herein, β-cyclodextrin (β-CD), a cheap and versatile material, was modified with methacrylate groups by reacting with methacryloyl chloride, giving an average degree of substitution of 3 per β-CD molecule. β-CD-methacrylate, which could function as a crosslinker, was then copolymerized with acrylamide monomer via free-radical copolymerization to form β-CD-polyacrylamide (β-CD-PAAm) hydrogel. Interestingly, in the structure of the β-CD-PAAm hydrogel, β-CD is not only a functional unit binding pollutant molecules through inclusion complexation, but also a structural unit crosslinking PAAm leading to the formation of the hydrogel 3D networks. Morphological studies showed that β-CD-PAAm gel had larger pore size than the control PAAm gel, which was synthesized using conventional crosslinker instead of β-CD-methacrylate. This was consistent with the higher swelling ratio of β-CD-PAAm gel than that of PAAm gel (29.4 vs. 12.7). In the kinetic adsorption studies, phenolphthalein, a model dye, and bisphenol A, propranolol hydrochloride, and 2-naphthol were used as model pollutants from different classes. The adsorption data for β-CD-PAAm gel fitted well into the pseudo-second-order model. In addition, the thermodynamic studies revealed that β-CD-PAAm gel was able to effectively adsorb the different dye and pollutants at various concentrations, while the control PAAm gel had very low adsorption, confirming that the pollutant removal was due to the inclusion complexation between β-CD units and pollutant molecules. The adsorption isotherms of the different dye and pollutants by the β-CD-PAAm gel fitted well into the Langmuir model. Furthermore, the β-CD-PAAm gel could be easily recycled by soaking in methanol and reused without compromising its performance for five consecutive adsorption/desorption cycles. Therefore, the β-CD-PAAm gel, which combines the advantage of an easy-to-handle hydrogel platform and the effectiveness of adsorption by β-CD units, could be a promising pollutant removal system for wastewater treatment applications.
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Rah, Sang-Chun. "Combustion of liquid fuels and pollutant formation: A review Part II. Pollutant formation." Korean Journal of Chemical Engineering 2, no. 1 (March 1985): 1–10. http://dx.doi.org/10.1007/bf02697543.
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Wang, Dongdong, Baolin Jiang, Fangzhou Li, and Wenshi Lin. "Investigation of the Air Pollution Event in Beijing-Tianjin-Hebei Region in December 2016 Using WRF-Chem." Advances in Meteorology 2018 (July 31, 2018): 1–12. http://dx.doi.org/10.1155/2018/1634578.
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The online coupled weather research and forecasting model with chemistry (WRF-Chem) was used to investigate an air pollution event during December 2016 in Beijing-Tianjin-Hebei urban agglomeration. Evaluation indicates that WRF-Chem captured the main weather conditions and pollutant distribution in this event. The primary meteorological drivers of air pollution formation were stationary atmospheric flows in both vertical and horizontal directions. High relative humidity and a strong temperature inversion accelerated event formation. In the shallow temperature inversion layer, aerosol particles were strongly confined near the surface, producing high surface contaminant concentrations. In addition, based on a normal experiment, three sensitivity experiments were constructed by adding hypothetical terrain (HT) of 400, 300, and 200 meters, over the region 115°E, 38.8°N to 117.54°E, 38.8°N. The results indicate that pollutants were diffused and transported below 400 meters, and the pollutant amounts concentrated south of the HT because of the HT blocking effect. Nevertheless, because there were less total contaminants north of the HT in the normal run, there was a slight decrease in pollutants north of the HT. There were some increases in pollution north of the HT because of local emissions, which were obstructed by the HT. The higher the HT, the stronger the blocking effect.
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Solevic, Tatjana, Branimir Jovancicevic, Miroslav Vrvic, and Hermann Wehner. "Oil pollutants in alluvial sediments: Influence of the intensity of contact with ground waters on the effect of microorganisms." Journal of the Serbian Chemical Society 68, no. 3 (2003): 227–34. http://dx.doi.org/10.2298/jsc0303227s.
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The influence of the intensity of interaction between oil pollutants and ground waters in alluvial sediments on the effect of microbial activity was investigated in this work. The study was based on a comparison of detailed analyses of two fractions of an oil pollutant originating from a Danube alluvial formation near the Pancevo Oil Refinery: fraction 1, separated from the aqueous layer by decantation, presumed to have been in less intensive interaction with water, and fraction 2, isolated from the aqueous emulsion by extraction with chloroform, presumed to have been in stronger interaction with water. Both fractions were shown to originate from the same type of oil pollutant. Nevertheless, significant compositional differences between the two fractions were observed. Asignificantly pronounced domination of even carbon number homologues of C18?C24 n-alkanes in fraction 2, atypical for crude oil pollutants, compared to the corresponding distribution observed in fraction 1, suggested a more intense activity, i.e., a much better effect of microorganisms in direct contact with the oil pollutant within the aqueous environment. The identification of even carbon number C14?C18 n-alcohols and C14?C18 fatty acids, as well as cholesterol, in fraction 2, suggested that microorganisms of the algal type in non-photosynthetic conditions were most probably responsible for the mentioned microbial processes.
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Sanguanpak, Samunya, Chart Chiemchaisri, Wilai Chiemchaisri, and Kazuo Yamamoto. "Effect of organic fouling on micro-pollutant rejection in membrane bioreactor treating municipal solid waste landfill leachate." Water Science and Technology 72, no. 4 (May 20, 2015): 561–71. http://dx.doi.org/10.2166/wst.2015.248.
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Effect of membrane fouling on the removal of micro-pollutants from municipal solid waste landfill leachate, i.e. 4-methyl-2,6-di-tert-butylphenol (BHT), bisphenol A (BPA), and bis(2-ethylhexyl)phthalate (DEHP), in membrane bioreactor (MBR) was investigated. Modifications of membrane surface properties were analyzed to determine their relationship with their removals. Membrane fouling was simulated with foulants of different particle sizes on cellulose acetate (CA) microfiltration membrane to investigate the effect of foulant characteristics on BHT, BPA, and DEHP retention in the filtration experiment. The rejection efficiencies of the organic micro-pollutants in the MBR were 82–97% by fouled membrane, and 70–90% by cleaned membrane. The fouled membrane provided higher rejection of micro-pollutants from about 5% for BPA and BHT to 19% for DEHP. These improvements were due to the modification of membrane surface characteristics in terms of surface morphology, and contact angle after membrane fouling. The degree of rejection was found to be dependent upon the characteristics of foulant deposited on CA membrane surface. Increasing foulant particle size and its density shifted the mechanism of micro-pollutant rejection from membrane pore narrowing to pore blocking and cake formation while increasing pollutant adsorption capacity onto the foulant layer.
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Freitas, Ismael Guidson Farias, José Carlos da Silva Alves, Ericka Voss Chagas Mariano, and Glauber Lopes Mariano. "Comportamento do dióxido de nitrogênio sobre a região nordeste do Brasil e sua relação com variáveis meteorológicas." Ciência e Natura 40 (March 22, 2018): 32. http://dx.doi.org/10.5902/2179460x30531.
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The emission of pollutants has become one of the subjects most debated in the last years, due to the increase of fixed emitting sources like industries and movable like the motor vehicles. In the Northeast of Brazil, the high concentrations of pollutants occur mainly in large urban centers, where one of these pollutants is emitted nitrogen dioxide, which is a highly polluting gas. Once observed high concentrations of this pollutant in the atmosphere can cause effects on human health and also influence the formation of acid rain. Thus the objective of this work was to investigate and quantify the total column of nitrogen dioxide gas over the northeastern region of Brazil based on data from the OMI sensor (Ozone Monitoring Instrument) between 2005 and 2015, through statistical techniques for analysis graphic and spatial. Significant variations of the pollutant were identified in the study area, highlighting Salvador, Teresina and Fortaleza, where they showed significant correlation results with meteorological variables. The results showed that Salvador had concentrations of up to 3.5 E+15 (1/m²) in the total NO2 column, while Teresina and Fortaleza had a maximum of 3.0 E+15 (1/m²) and 2,6 E+15 (1/m²), respectively. Therefore, the variations were different in the cities.
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Toyoda, Masahiro, Beata Tryba, Fumi Koujin, Tomoki Tsumura, and Michio Inagaki. "Carbon-Coated TiO2 - Hybridization between Photoactivity and Adsorptivity." Advances in Science and Technology 46 (October 2006): 180–87. http://dx.doi.org/10.4028/www.scientific.net/ast.46.180.
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Carbon-coated TiO2 photocatalysts were prepared by a simple heat treatment of the powder mixtures of anatase-type TiO2 with PVA at a temperature of 700 and 900 oC in a N2 atomosphere. Diffuse optical reflectance spectra for carbon-coated TiO2 showed the absorption edge for anatase structure clearly, overlapping with absorption due to coated carbon over whole range of wavelegth. These carbon-coated TiO2 photocatalysts had relatively high apparent BET surface area, from 50 to 170 m2/g, which suggested the formation of porous carbon layers, and showed relatively high adsorption of various pollutants, methylene blue (MB), reactive black (RB-5), phenol (Ph) and iminoctadine triacetate (IT), in water. Photocatalytic activity of carbon-coated TiO2 thus prepared was evaluated through the determination of the rate constant for the decomposition of different pollutants in water. Rate constant values were strongly depend on the pollutants, but their dependence on the crystallinity of TiO2 phase. The relations between adsorptivity and rate constant for four pollutants looked similar with each other, and the pollutants adsorbed in the larger amount was decomposed with the higher rate. Adsorptivity of carbon-coated TiO2 photocatlysts was determined and discussed on the relations to BET surface area, amount of carbon coated and also rate constant k for the decomposition of MB, RB5, Ph and IT. Adsorptivity of carbon-coated catalysts depends strongly on the adsorbate (pollutant) but also on the surface nature of carbon layer on TiO2 particles. The relations between adsorptivity and rate constant k for four pollutants looked similar, suggesting that the pollutant adsorbed in the larger amount being decomposed with the higher rate.
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Guerrero, Viviana Vanesa Urbina, Marcos Vinicius Bueno de Morais, Edmilson Dias de Freitas, and Leila Droprinchinski Martins. "Numerical Simulation of Nocturnal Ozone Increase in Metropolitan Area of São Paulo." Environmental Sciences Proceedings 4, no. 1 (November 13, 2020): 24. http://dx.doi.org/10.3390/ecas2020-08140.
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In large cities, pollution can not only cause deaths and illness due to exposure of people to it, but it can also reduce visibility on days of high atmospheric stability and high emission of pollutants, which can even result in vehicular accidents. Ozone is an atmospheric oxidizing gas that forms in minimal amounts naturally. People’s health can be affected by the ozone present in the air they breathe, even in low concentrations, which can worsen preexisting diseases and increase hospital admissions for respiratory diseases, especially in babies, after episodes of high pollutant levels. An increase in secondary peaks during the night of this atmospheric pollutant occurs in several parts of the world, but its formation depends on the local condition. In this sense, this work aims to study the regional atmospheric characteristics for the nocturnal ozone formation in the Metropolitan Area of São Paulo (MASP). For this, the Simple Photochemical Module (SPM) coupled with the BRAMS (Brazilian Developments of Regional Atmospheric Modeling System) will be used to simulate this condition for the urban region. The results showed that the secondary nocturnal maximum of ozone concentrations in MASP is related to vertical transport of this pollutant from higher levels of the atmosphere to the surface.
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Olsen, Daniel B., and Charles E. Mitchell. "Formaldehyde Formation in Large Bore Engines Part 2: Factors Affecting Measured CH2O." Journal of Engineering for Gas Turbines and Power 122, no. 4 (December 29, 1999): 611–16. http://dx.doi.org/10.1115/1.1290586.
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Current research shows that the only hazardous air pollutant of significance emitted from large bore natural gas engines is formaldehyde CH2O. A literature review on formaldehyde formation is presented focusing on the interpretation of published test data and its applicability to large bore natural gas engines. The relationship of formaldehyde emissions to that of other pollutants is described. Formaldehyde is seen to have a strong correlation to total hydrocarbon (THC) level in the exhaust. It is observed that the ratio of formaldehyde to THC concentration is roughly 1.0–2.5 percent for a very wide range of large bore engines and operating conditions. The impact of engine operating parameters, load, rpm, spark timing, and equivalence ratio, on formaldehyde emissions is also evaluated. [S0742-4795(00)01004-8]
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Bhandari, Sobika, Darbin Kumar Poudel, Rishab Marahatha, Sonika Dawadi, Karan Khadayat, Sitaram Phuyal, Shreesti Shrestha, et al. "Microbial Enzymes Used in Bioremediation." Journal of Chemistry 2021 (February 8, 2021): 1–17. http://dx.doi.org/10.1155/2021/8849512.
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Emerging pollutants in nature are linked to various acute and chronic detriments in biotic components and subsequently deteriorate the ecosystem with serious hazards. Conventional methods for removing pollutants are not efficient; instead, they end up with the formation of secondary pollutants. Significant destructive impacts of pollutants are perinatal disorders, mortality, respiratory disorders, allergy, cancer, cardiovascular and mental disorders, and other harmful effects. The pollutant substrate can recognize different microbial enzymes at optimum conditions (temperature/pH/contact time/concentration) to efficiently transform them into other rather unharmful products. The most representative enzymes involved in bioremediation include cytochrome P450s, laccases, hydrolases, dehalogenases, dehydrogenases, proteases, and lipases, which have shown promising potential degradation of polymers, aromatic hydrocarbons, halogenated compounds, dyes, detergents, agrochemical compounds, etc. Such bioremediation is favored by various mechanisms such as oxidation, reduction, elimination, and ring-opening. The significant degradation of pollutants can be upgraded utilizing genetically engineered microorganisms that produce many recombinant enzymes through eco-friendly new technology. So far, few microbial enzymes have been exploited, and vast microbial diversity is still unexplored. This review would also be useful for further research to enhance the efficiency of degradation of xenobiotic pollutants, including agrochemical, microplastic, polyhalogenated compounds, and other hydrocarbons.
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Boussouara, Karima, and Mahfoud Kadja. "Empirical soot formation and oxidation model." Thermal Science 13, no. 3 (2009): 35–46. http://dx.doi.org/10.2298/tsci0903035b.
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Modelling internal combustion engines can be made following different approaches, depending on the type of problem to be simulated. A diesel combustion model has been developed and implemented in a full cycle simulation of a combustion, model accounts for transient fuel spray evolution, fuel-air mixing, ignition, combustion, and soot pollutant formation. The models of turbulent combustion of diffusion flame, apply to diffusion flames, which one meets in industry, typically in the diesel engines particulate emission represents one of the most deleterious pollutants generated during diesel combustion. Stringent standards on particulate emission along with specific emphasis on size of emitted particulates have resulted in increased interest in fundamental understanding of the mechanisms of soot particulate formation and oxidation in internal combustion engines. A phenomenological numerical model which can predict the particle size distribution of the soot emitted will be very useful in explaining the above observed results and will also be of use to develop better particulate control techniques. A diesel engine chosen for simulation is a version of the Caterpillar 3406. We are interested in employing a standard finite-volume computational fluid dynamics code, KIVA3V-RELEASE2.
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Madrange, L., P. Ehabouryi, O. Ferrandon, M. Mazeti, and J. Rodeaud. "Étude de la formation et de la stabilité des mousses chimiques de surface de la Vienne." Revue des sciences de l'eau 6, no. 3 (April 12, 2005): 315–35. http://dx.doi.org/10.7202/705178ar.
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Le recensement de la charge polluante rejetée dans la rivière Vienne (France) par les usines et les stations d'épuration de Limoges à Confolens a été effectué. Des campagnes de prélèvement et d'observations visuelles ont permis de localiser les lieux d'apparition de mousses en aval d'usines de fabrication de pâte à papier et de cartons. L'étude du pouvoir moussant des mélanges des deux principaux rejets polluants (papeterie et cartonnerie) a permis de mettre en évidence des phénomènes de synergie entre certains mélanges se traduisant à la fois par une augmentation du pouvoir moussant et de la stabilité de la mousse dans le temps. L'étude par « HPLC » montre l'apparition de pics supplémentaires confirmant l'interaction entre les constituants des rejets; le principal effluent a pu être suivi à l'aide de ses caractéristiques chimiques dans la rivière et dans les mousses jusqu'à Confolens.
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Wang, Han, Shulan Wang, Jingqiao Zhang, and Hui Li. "Characteristics of PM2.5 Pollution with Comparative Analysis of O3 in Autumn–Winter Seasons of Xingtai, China." Atmosphere 12, no. 5 (April 28, 2021): 569. http://dx.doi.org/10.3390/atmos12050569.
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Pollutants emission, meteorological conditions, secondary formation, and pollutants transport are the main reasons for air pollution. A comprehensive air pollution analysis was conducted from the above four aspects in the autumn–winter seasons of 2017–2018 and 2018–2019 at Xingtai, China. In addition, the relationship between PM2.5 and O3 was also studied from the aspects of secondary formation and meteorological conditions to find the rules of cooperative management of PM2.5 and O3 combined pollution. Taking measures of concentrated and clean heating and controlling biomass burning could make the concentrations of EC, K+ and SO42− decrease. The variation trends of PM2.5 and O3 concentration in the autumn–winter season of Xingtai were different, and with the increase in secondary formation effects, the concentration of O3 decreased. Furthermore, the key meteorological conditions that affected O3 and PM2.5 formation were temperature and relative humidity, respectively. The relationships of NOR (nitrate oxidation rate) and SOR (sulfate oxidation rate) against temperature presented a “U” shape, suggesting that gas-phase oxidation and gas–solid-phase oxidation were all suppressed at a temperature of around 4 °C. The cities located in the east had more pollutant transporting effects during the pollution processes of Xingtai, and the main transport routes of O3 and PM2.5 were not all the same.
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ZAUGG, S., A. BLACKHAM, P. HEDMAN, and L. SMOOT. "Sulphur pollutant formation during coal combustion." Fuel 68, no. 3 (March 1989): 346–53. http://dx.doi.org/10.1016/0016-2361(89)90100-2.
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Singh, Balpreet, Himanshi Sharma, Barinder Kaur, Jaskaran Singh, Gurpreet Singh, Navalpreet Singh, and Deepak Kukkar. "Highly Efficient Yttrium Based Metal Organic Framework for Removal of Pollutant Dyes." Nano Hybrids and Composites 12 (November 2016): 51–56. http://dx.doi.org/10.4028/www.scientific.net/nhc.12.51.
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Highly porous crystalline luminescent metal Organic Frameworks (MOFs) were synthesized by conjugating Yttrium nitrate and Benzene Tri Carboxylate (BTC) in the presence of surfactant Cetyl Tri methyl Ammonium Bromide. A characteristic blue emission peak around 400 nm of Y upon excitation with UV light and peaks through Infra-Red spectroscopy revealed the formation of co-ordinate bond between Y and BTC, thereby confirming the formation of MOF nanoparticles (NPs). The nanoparticles were studied for potential removal of pollutants by encapsulation of the dye methylene blue (MB). Optical analysis affirmed the encapsulation of dye particles within the porous MOF NPs as dye absorption decreased around 600nm. This study offers great promise of using MOF NPs as platform for sensing of analytes in solution and removal of pollutant materials.
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Moxley, Karis, and Stefan Schmidt. "Isolation of a phenol-utilizing marine bacterium from Durban Harbour (South Africa) and its preliminary characterization as Marinobacter sp. KM2." Water Science and Technology 65, no. 5 (March 1, 2012): 932–39. http://dx.doi.org/10.2166/wst.2012.940.
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Many aromatic hydrocarbons assigned to the so-called high production volume chemicals (HPVCs) are frequently encountered constituents of wastewaters that end up in the sea. Although the pollutant-degrading capabilities of freshwater bacteria are well known, the catabolism of pollutants by marine bacteria has received limited attention. A marine bacterium with the ability to aerobically utilize phenol – an HPVC and common aromatic pollutant – as its sole source of carbon and energy, was isolated from water samples from Durban Harbour, South Africa. The isolate, designated strain KM2, was assigned to the genus Marinobacter based on a variety of phenotypic properties and by analysis of the 16S rRNA gene sequence. The isolate displays an absolute growth requirement for NaCl which cannot be offset by replacement of NaCl with other salts. In addition to 4-methylphenol and 3,4-dimethylphenol, it utilizes a range of aliphatic hydrocarbons such as butan-1-ol and hexadecane under aerobic conditions. The transient formation of an intermediate exhibiting the UV–Vis spectral characteristics for 2-hydroxymuconic semialdehyde in cultures growing on phenol suggests that the isolate catabolizes this compound via the meta cleavage pathway. These results indicate that members of the genus Marinobacter might participate in the elimination of aromatic pollutants in South African marine environments.
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Rueda-Márquez, Juan José, Irina Levchuk, Manuel Manzano, and Mika Sillanpää. "Toxicity Reduction of Industrial and Municipal Wastewater by Advanced Oxidation Processes (Photo-Fenton, UVC/H2O2, Electro-Fenton and Galvanic Fenton): A Review." Catalysts 10, no. 6 (June 1, 2020): 612. http://dx.doi.org/10.3390/catal10060612.
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The application of Fenton-based advanced oxidation processes (AOPs), such as photo-Fenton or electro-Fenton for wastewater treatment have been extensively studied in recent decades due to its high efficiency for the decomposition of persistent organic pollutants. Usually Fenton-based AOPs are used for the degradation of targeted pollutant or group of pollutants, which often leads to the formation of toxic by-products possessing a potential environmental risk. In this work, we have collected and reviewed recent findings regarding the feasibility of Fenton-based AOPs (photo-Fenton, UVC/H2O2, electro-Fenton and galvanic Fenton) for the detoxification of real municipal and industrial wastewaters. More specifically, operational conditions, relevance and suitability of different bioassays for the toxicity assessment of various wastewater types, cost estimation, all of which compose current challenges for the application of these AOPs for real wastewater detoxification are discussed.
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Fu, Songlin, Chenbo Xie, Peng Zhuang, Xiaomin Tian, Zhanye Zhang, Bangxin Wang, and Dong Liu. "Study of Persistent Foggy-Hazy Composite Pollution in Winter over Huainan Through Ground-Based and Satellite Measurements." Atmosphere 10, no. 11 (October 28, 2019): 656. http://dx.doi.org/10.3390/atmos10110656.
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Through the observation of ground-based LIDAR and satellite sensors, the weather conditions of continuous foggy-hazy alternations in the Huainan region from 26 December 2016 to 5 January 2017 were analyzed and observed. In this study, the formation and influence of this event were discussed by analyzing pollutant concentrations, meteorological factors and aerosol optical characteristics. The concentrations of PM10 and PM2.5 increased significantly. The maximum value of PM10 was 412 μg/m3, and the maximum value of PM2.5 was 258 μg/m3. The transportation of pollutants and the production of man-made pollutants promote the accumulation of pollutants. In this weather process, meteorological factors such as the surface wind speed, humidity, surface temperature, and inversion also promote the accumulation of pollutants, which is the main reason for the formation of this weather process. Furthermore, the near surface air mass mainly came from the cities near the Huainan region and the heavily polluted areas in the north, while the upper air mass came from Inner Mongolia. In this paper, piecewise inversion was adopted to achieve accurate all-weather extinction coefficient profile inversion by reasonably selecting a cloud LIDAR ratio through a backscatter ratio, and the LIDAR ratio of cloud in this period was 22.57–34.14 Sr. By means of extinction coefficient inversion and correlation analysis, the correlation index of PM2.5 and the aerosol optical depth (AOD) was 0.7368, indicating that there was a positive correlation between PM2.5 and AOD, and AOD can also reflect the pollution condition of this region. The formation process of foggy-hazy weather in the Huainan region studied in this paper can provide a research basis for foggy-hazy pollution in this region.
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Ahmed, Salman Abdu, Song Zhou, Yuanqing Zhu, Yongming Feng, Adil Malik, and Naseem Ahmad. "Influence of Injection Timing on Performance and Exhaust Emission of CI Engine Fuelled with Butanol-Diesel Using a 1D GT-Power Model." Processes 7, no. 5 (May 21, 2019): 299. http://dx.doi.org/10.3390/pr7050299.
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Injection timing variations have a significant effect on the performance and pollutant formation in diesel engines. Numerical study was conducted to investigate the impact of injection timing on engine performance and pollutants in a six-cylinder turbocharged diesel engine. Diesel fuel with different amounts (5%, 15%, and 25% by volume) of n-butanol was used. Simulations were performed at four distinct injection timings (5°, 10°, 20°, 25°CA bTDC) and two distinct loads of brake mean effective pressure (BMEP = 4.5 bar and 10.5 bar) at constant engine speed (1800 rpm) using the GT-Power computational simulation package. The primary objective of this research is to determine the optimum injection timing and optimum blending ratio for improved efficiencies and reduced emissions. Notable improvements in engine performance and pollutant trends were observed for butanol-diesel blends. The addition of butanol to diesel fuel has greatly diminished NOX and CO pollutants but it elevated HC and CO2 emissions. Retarded injection timing decreased NOX and CO2 pollutants while HC and CO2 emissions increased. The results also indicated that early injection timings (20°CA bTDC and 25°CA bTDC) lowered both CO2 and unburned hydrocarbon emissions. Moreover, advanced injection timing slightly improved brake thermal efficiency (BTE) for all engine loads. It is concluded that retarded injection timing, i.e., 10°CA bTDC demonstrated optimum results in terms of performance, combustion and emissions and among the fuels 15B showed good outcome with regard to BTE, higher heat release rate, and lower pollution of HC, CO, and NOx.
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Chen, Junjie, Xuhui Gao, and Deguang Xu. "Catalytic Combustion Characteristics of Methane-Air Mixtures in Small-Scale Systems at Elevated Temperatures." Catalysts 8, no. 10 (October 6, 2018): 439. http://dx.doi.org/10.3390/catal8100439.
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The catalytic combustion characteristics of methane-air mixtures in small-scale systems were investigated at elevated temperatures, with particular emphasis on identifying the main factors that affect formation and removal of combustion-generated pollutants. Computational fluid dynamics simulations were performed using detailed chemical kinetic mechanisms, and more insights were offered into the phenomena occurring in the temperature range where homogeneous and heterogeneous reaction pathways are both important. Reaction engineering analysis was performed to provide an in-depth understanding of how to achieve low emissions of pollutants. Spatial distributions of the major species involved were presented to gain insight into the interplay between the two competing pathways involved. The results indicated that the distribution of oxidized products depends critically on the feed composition, dimension, temperature, and pressure. Small-scale catalytic systems enable low emissions of pollutants even in a high temperature environment, along with high combustion efficiency. The interplay between the two competing pathways via radicals is strong, and the heterogeneous pathway can significantly inhibit the homogeneous pathway. The inhibiting effect also accounts for the low emissions of nitrogen oxides. Almost all of the nitrogen oxides emitted by small-scale catalytic systems are nitric oxide. Catalytic combustion technology can be used to reduce the formation of undesired products, especially pollutant nitrogen oxide gases far below what can be achieved without catalysts. Recommendations for the design of small-scale catalytic systems are provided.
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Zhuang, Xueqiang, Qiqi Wu, Xihe Huang, Haohong Li, Tianjin Lin, and Yali Gao. "A Three-Component Hybrid Templated by Asymmetric Viologen Exhibiting Visible-Light-Driven Photocatalytic Degradation on Dye Pollutant in Maritime Accident Seawater." Catalysts 11, no. 5 (May 18, 2021): 640. http://dx.doi.org/10.3390/catal11050640.
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The increasing dangerous chemical pollutants led by shipping accidents call for the new pollutant treatment strategy. In this work, a new three-component hybrid {[(BiI6)I13]·2I3·(H-BPA)4}n (1) can be used in dye degradation in seawater. The highly interesting feature of 1 lies in its unique 1-D Z-shape [(BiI6)I13]n6− infinite chain constructed from the I···I contacts between mono-nuclear (BiI6)3− anions and I133− polyiodide anions. Finally, the hydrogen bonds between [(BiI6)I13]n6− polyanions and H-BPA2+ cations contribute to the formation a quasi-3-D network. Specifically, 1 exhibits the wide absorption zone from ultraviolet to visible regions and high charge-separation efficiency, hinting its application in visible-light catalysis. As expected, 1 represents photocatalytic activity for the degradation of rhodamine B in seawater with degradation ratio of 90%, and the photocatalytic performance is stable. This work might provide new photocatalytic material for pollutant treatment in shipping accidents.
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Vejerano, Eric P., Jeonghyeon Ahn, Junaid Latif, and Mustafa M. amun. "Environmentally Persistent Free Radicals as Sources of POPs." Advances in Environmental and Engineering Research 02, no. 02 (January 17, 2021): 1. http://dx.doi.org/10.21926/aeer.2102010.
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Environmentally persistent free radicals (EPFRs) are a new class organic pollutant sharing some of the attributes of persistent organic pollutants (POPs). This opinion/short review aims to describe the properties of EPFRs that merit their recognition as an additional and potentially significant source of POPs. EPFRs are ubiquitous in diverse environments because of multiple factors: (1) organic precursors from anthropogenic, biogenic, and other natural emission sources are abundant; multiple mechanisms in PM and soils form (2) EPFRs; and (3) EPFRs are stable and persist for a long time, thereby, accumulate in the environment and potentially transported long range. The hazards of EPFRs arise from their ability to induce oxidative stress and the formation of hazardous byproducts. EPFRs are ultimately deactivated by reactive processes, yielding molecular recombination byproducts that are structurally similar to those classified as POPs. It is plausible that EPFRs may form POPs in vivo in organisms; therefore, they are potential additional sources of exogenous POPs. Understanding the formation of EPFRs and extensive investigation of the pollutants generated from their recombination will add to the growing body of knowledge on their environmental and health hazards.
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Petranović, Zvonimir, Tibor Bešenić, Milan Vujanović, and Neven Duić. "Modelling pollutant emissions in diesel engines, influence of biofuel on pollutant formation." Journal of Environmental Management 203 (December 2017): 1038–46. http://dx.doi.org/10.1016/j.jenvman.2017.03.033.
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Qi, Fengsheng, Zisong Wang, Baokuan Li, Zhu He, Jakov Baleta, and Milan Vujanovic. "Numerical study on characteristics of combustion and pollutant formation in a reheating furnace." Thermal Science 22, no. 5 (2018): 2103–12. http://dx.doi.org/10.2298/tsci180118277q.
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Energy consumption of fuel-fired industrial furnace accounts for about 23% of the national total energy consumption every year in China. Meanwhile, the reduction of combustion-generated pollutants in furnace has become very important due to the stringent environment laws and policy introduced in the recent years. It is therefore a great challenge for the researchers to simultaneously enhance the fuel efficiency of the furnace while controlling the pollution emission. In this study, a transient 3-D mathematical combustion model coupled with heat transfer and pollution formation model of a walking-beam-type reheating furnace has been developed to simulate the essential combustion, and pollution distribution in the furnace. Based on this model, considering nitrogen oxides formation mechanism, sensitivity study has been carried out to investigate the influence of fuel flow rate, air-fuel ratio on the resultant concentration of nitrogen oxides in the flue gas. The results of present study provide valuable information for improving the thermal efficiency and pollutant control of reheating furnace.
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Pershing, David W. "Pollutant formation and control/hazardous waste incineration." Energy & Fuels 7, no. 6 (November 1993): 782–85. http://dx.doi.org/10.1021/ef00042a013.
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Huang, Lai, Jidong Lu, Shijie Wang, and Zhijuan Hu. "Numerical Simulation of Pollutant Formation in Precalciner." Canadian Journal of Chemical Engineering 83, no. 4 (May 19, 2008): 675–84. http://dx.doi.org/10.1002/cjce.5450830408.
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Hübner, Matthias, Peter Koch, Hans Zellbeck, Alfred Leipertz, and Andreas Kerst. "Combustion and pollutant formation in diesel engines." MTZ worldwide 69, no. 4 (April 2008): 48–55. http://dx.doi.org/10.1007/bf03226905.
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Valdez Salas, Benjamin, Michael Schorr Wiener, Roumen Zlatev Koytchev, Gustavo López Badilla, Rogelio Ramos Irigoyen, Monica Carrillo Beltrán, Nicola Radnev Nedev, Mario Curiel Alvarez, Navor Rosas Gonzalez, and Jose María Bastidas Rull. "Copper Corrosion by Atmospheric Pollutants in the Electronics Industry." ISRN Corrosion 2013 (October 2, 2013): 1–7. http://dx.doi.org/10.1155/2013/846405.
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Hydrogen sulphide (H2S) is considered one of the most corrosive atmospheric pollutants. It is a weak, diprotic, reducing acid, readily soluble in water and dispersed into the air by winds when emitted from natural, industrial, and anthropogenic sources. It is a pollutant with a high level of toxicity impairing human health and the environment quality. It attacks copper forming thin films of metallic sulphides or dendrite whiskers, which are cathodic to the metal substrate, enhancing corrosion. H2S is actively involved in microbially influenced corrosion (MIC) which develops in water, involving sulphur based bacteria, in oxidizing and reducing chemical reactions. H2S is found in concentrated geothermal brines, in the atmosphere of geothermal fields, and in municipal sewage systems. Other active atmospheric pollutants include SOX, NOX, and CO. This investigation reports on the effects of H2S on copper in microelectronic components of equipment and devices, with the formation of nonconductive films that lead to electrical failures.
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Emery, Brittni R., Derek C. Montague, Robert A. Field, and Thomas R. Parish. "Barrier Wind Formation in the Upper Green River Basin of Sublette County, Wyoming, and Its Relationship to Elevated Ozone Distributions in Winter." Journal of Applied Meteorology and Climatology 54, no. 12 (December 2015): 2427–42. http://dx.doi.org/10.1175/jamc-d-15-0103.1.
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AbstractMeteorological factors affect the concentrations and distributions of pollutants during episodes of degraded air quality. Over the last 10 years, the upper Green River basin (UGRB) of Sublette County, Wyoming, has experienced numerous wintertime ozone episodes stimulated by emissions from oil and natural gas development operations, resulting in the region being determined to be in marginal nonattainment of the National Ambient Air Quality Standards. Examination of surface wind field patterns in the UGRB using observations from a network of surface monitoring stations for 2011 and 2012, with an emphasis on ozone-episode days, confirms that increased ozone concentrations are most frequently measured on days on which winds are light and variable. Dispersion and dilution of ozone and its precursor pollutants on these days is therefore inefficient, and so these episodes invariably occur within and close by the gas fields. On days that instead experience afternoon southeasterly winds, episodes can often be observed at locations on the northwestern perimeter of the basin remote from pollutant source regions. Simulations using the Weather Research and Forecasting Model, conducted for the case study of 15 February 2011, identify these southeasterlies as barrier winds caused by southwesterly flow at 700 hPa impinging on the Wind River Mountains that flank the UGRB to the northeast. Characterization of the barrier wind and the overall airflow patterns facilitates more accurate future forecasting of the time-dependent geographical distribution of increased concentrations of ozone and other pollutants in the region.
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Turkienė, Nora, Aušra Zigmontienė, Kęstutis Buinevičius, and Raminta Plečkaitienė. "Sewage Sludge Combustion – Experimental and Theoretical Analysis." Chemical and Process Engineering 34, no. 2 (June 1, 2013): 203–14. http://dx.doi.org/10.2478/cpe-2013-0017.
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Whereas the use of biofuels has attracted increasing attention, the aim of this paper is to investigate the possibility of using sewage sludge as biofuel. Preparation of untreated and stabilised sludge with natural additives is described, as well as combusting method applied and experimental results of combusting are presented based on the assessment of composition of emitted pollutants and their concentrations in the exhaust gas. NOx formation in the exhaust gas has been analysed in depth. The results of investigations have shown that the use of dried sewage sludge possesses a positive energy balance. Therefore, the sludge may be used as fuel. The obtained experimental results demonstrate that during combustion, pollutant concentrations vary depending on oxygen content (O2), while formation of nitrogen oxides is strongly influenced by fuel-bound nitrogen. Also, a generalized equation of calculating fuel bound nitrogen conversion into NOx is presented.
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Rasovic, Aleksandar, Branimir Jovancicevic, Dusan Sladic, Zoran Kljajic, Georg Scheeder, and Hermann Wehner. "Application of biological markers for the identification of oil-type pollutants in recent sediments: Alluvial formation of the Danube river, Oil refinery Pancevo." Chemical Industry 56, no. 1 (2002): 17–24. http://dx.doi.org/10.2298/hemind0201017r.
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The purpose of this paper was to examine to which extent the abundance and distribution of certain biological markers may be used for the identification of oil-type pollutants in recent sediments and ground waters. The samples were taken from the area of the Oil Refinery Pancevo (alluvial formation of the Danube River). The organic matter of the investigated samples was isolated using an extraction method with chloroform. The group composition and usual biological markers were analyzed in the obtained extracts. n-Alkanes and acyclic isoprenoids, pristane and phytane were analyzed using gas chromatographie (GC) analysis of saturated hydrocarbons. Polycyclic alkanes of the sterane and terpane type were analyzed using gas chromatography-mass spectrometry (GC-MS), i.e. by analyzing the carbamide non-adduct of the total alkane fraction (Single Ion Monitoring SIM-technique). The obtained results indicate that n-alkanes can be used for the identification of oil-type pollutants (for example, if the oil-pollutant is biodegraded or present in very low concentrations), and steranes and triterpanes can be used as very reliable indicators of oil-type pollution in recent sediments and ground waters.
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Liu, Shoujun, Ju Shangguan, Song Yang, Wenguang Du, Xudong Yan, and Kaixia Zhang. "Producing Effective and Clean Coke for Household Combustion Activities to Reduce Gaseous Pollutant Emissions." Journal of Chemistry 2019 (November 13, 2019): 1–12. http://dx.doi.org/10.1155/2019/7142804.
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Nowadays, the gaseous pollutant emissions, including particulate matter (PM), sulfur dioxide (SO2), and nitrogen oxide (NOx) from household coal combustion, cause great threat to environment and public health by contributing to severe haze in China. Particularly, a clean coke free of the major pollutants precursors (sulfur and nitrogen compounds) by sulfur fixation and denitrification has been deemed as an effective strategy to reducing pollutants. In this paper, a preprocessed coke was prepared by co-pyrolysis of high-sulfur coal with the assistance of calcium-based and iron-based complexes at high temperature. The results show that high-temperature co-pyrolysis could remove the volatile compounds that are major precursors for the formation of gaseous pollutants from the raw coal. During the coking process, the sulfur can be removed by being fixed in the form of CaS in presence of a Ca-based complex, which could be beneficial for the CaSO4 during the coke combustion. The volatile nitrogen is transferred to the gas phase with the addition of Fe-based complexes, which effectively reduce the residual nitrogen in coke. As a result, Ca-based additives captured the released SO2 and formed CaSO4 during the combustion process. In addition, in the presence of Fe-based complexes, both char and CO react with NOx to form N2, which leads to a reduction in NOx emissions during combustion. Additionally, the replacement of current residential coal with a new type of clean coke is a facile method for reducing gaseous pollutant emissions from household activities to protect the atmospheric environment. The average emission factors (EFs) of PM, SO2, and NOx for the prepared clean coke were small during combustion and were much lower than the EFs of the tested raw coal, semicoke, and briquettes.
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Wang, Yaqiong, Ke Xu, and Shaomin Li. "The Functional Spatio-Temporal Statistical Model with Application to O3 Pollution in Beijing, China." International Journal of Environmental Research and Public Health 17, no. 9 (May 2, 2020): 3172. http://dx.doi.org/10.3390/ijerph17093172.
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In recent years, with rapid industrialization and massive energy consumption, ground-level ozone ( O 3 ) has become one of the most severe air pollutants. In this paper, we propose a functional spatio-temporal statistical model to analyze air quality data. Firstly, since the pollutant data from the monitoring network usually have a strong spatial and temporal correlation, the spatio-temporal statistical model is a reasonable method to reveal spatial correlation structure and temporal dynamic mechanism in data. Secondly, effects from the covariates are introduced to explore the formation mechanism of ozone pollution. Thirdly, considering the obvious diurnal pattern of ozone data, we explore the diurnal cycle of O 3 pollution using the functional data analysis approach. The spatio-temporal model shows great applicational potential by comparison with other models. With application to O 3 pollution data of 36 stations in Beijing, China, we give explanations of the covariate effects on ozone pollution, such as other pollutants and meteorological variables, and meanwhile we discuss the diurnal cycle of ozone pollution.
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Salazar, Cristian, Anna I. Kurbatova, and Milana E. Kupriyanova. "Quito’s coronavirus curfew: Escalating tropospheric ozone pollution." E3S Web of Conferences 211 (2020): 04008. http://dx.doi.org/10.1051/e3sconf/202021104008.
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The effect of the curfew due to the pandemic of Covid-19 virus on the levels of air pollution in the historic center of Quito was evaluated with a focus on tropospheric ozone (O3). During the curfew period the daily O3 mean concentration increased by 96%, 109% and 95% in comparison to the concentrations for the same period in the years 2017, 2018 and 2019. This increase is mainly explained by considerable reduction in NOx emissions, thus there was little titration of ozone accumulated in the city environment due to its shallow boundary layer by NO, reaching its maximum concentration at midday. Among studied pollutants that influence O3 formation (CO, NO2, PM2.5) during the curfew the contaminant that showed the greatest reduction in the mean concentration compared to three previous years was NO2, followed by CO and PM2.5. The daily O3 8-hour mean concentrations during the curfew both on weekdays and weekends were lower than the limit values. These results are relevant for designing abatement policies of secondary pollutants such as O3 under strict measures of control of primary pollutant emissions.
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Sobko, Z. Z., N. M. Vozniuk, and O. A. Lykho. "Evolution of open air quality of urbanized territories under Covid-19 pandemic conditions." Ukrainian Journal of Ecology 10, no. 6 (December 10, 2020): 48–53. http://dx.doi.org/10.15421/2020_256.
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Current state of world affairs in 2020 during quarantine enforced due to COVID-19 pandemic is characterized, on the one hand, with economic recession, but on the other hand, also with improvement of ecological state of environment. Thus a unique opportunity came up to study processes of open air conditions formation in settlements in circumstances of restricted economic activity and limitations imposed on all kinds of transportation. This article presents results of research of trends of formation of open air quality of urbanized territories (using city of Rivne as an example) during quarantine enforced due to COVID-19 pandemic. It is determined that due to introduction of quarantine measures air quality has improved. So, during the quarantine as well as after relaxation of quarantine measures only concentration of formaldehyde in open air of Rivne city did exceed average daily MAC. Primary source of open air pollution in Rivne city is motor vehicles which comprise 79% of total amount of pollutant emissions. Main pollutants which influence formation of open air quality in the city are: dust, sulfur dioxide, nitrogen dioxide, hydrogen fluoride and formaldehyde. They exceeded average daily MAC by factor of 1.3 to 32. Complex air pollution index (CAPI) was equal to 5.4 during quarantine restrictions but grew to 5.7 when the restrictions were partially loosened. Thus, air pollution level was evaluated as "mild pollution". During the corresponding periods of 2019 this index was changing from 6.9 ("mild air pollution") to 7.7 ("polluted air") respectively. Open air pollution level is determined by a complex of constituents including pollutant emission amounts, their specifics and dependency on meteorological factors. Due to this aspect we have performed statistical examinations to determine dependency of open air pollutant concentrations on meteorological conditions using multiple correlation coefficients. Strong correlation was exhibited for nitrogen oxide, hydrogen chloride and ammonia: multiple correlation coefficients fall within 0.76-0.80 range; moderate correlation was seen for dust, sulfur dioxide, nitrogen dioxide, hydrogen disulphide, phenol and formaldehyde with multiple correlation coefficients varying in 0.51-0.70 range.
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Zhong, Junting, Xiaoye Zhang, Yunsheng Dong, Yaqiang Wang, Cheng Liu, Jizhi Wang, Yangmei Zhang, and Haochi Che. "Feedback effects of boundary-layer meteorological factors on cumulative explosive growth of PM<sub>2.5</sub> during winter heavy pollution episodes in Beijing from 2013 to 2016." Atmospheric Chemistry and Physics 18, no. 1 (January 10, 2018): 247–58. http://dx.doi.org/10.5194/acp-18-247-2018.
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Abstract. In January 2013, February 2014, December 2015 and December 2016 to 10 January 2017, 12 persistent heavy aerosol pollution episodes (HPEs) occurred in Beijing, which received special attention from the public. During the HPEs, the precise cause of PM2.5 explosive growth (mass concentration at least doubled in several hours to 10 h) is uncertain. Here, we analyzed and estimated relative contributions of boundary-layer meteorological factors to such growth, using ground and vertical meteorological data. Beijing HPEs are generally characterized by the transport stage (TS), whose aerosol pollution formation is primarily caused by pollutants transported from the south of Beijing, and the cumulative stage (CS), in which the cumulative explosive growth of PM2.5 mass is dominated by stable atmospheric stratification characteristics of southerly slight or calm winds, near-ground anomalous inversion, and moisture accumulation. During the CSs, observed southerly weak winds facilitate local pollutant accumulation by minimizing horizontal pollutant diffusion. Established by TSs, elevated PM2.5 levels scatter more solar radiation back to space to reduce near-ground temperature, which very likely causes anomalous inversion. This surface cooling by PM2.5 decreases near-ground saturation vapor pressure and increases relative humidity significantly; the inversion subsequently reduces vertical turbulent diffusion and boundary-layer height to trap pollutants and accumulate water vapor. Appreciable near-ground moisture accumulation (relative humidity> 80 %) would further enhance aerosol hygroscopic growth and accelerate liquid-phase and heterogeneous reactions, in which incompletely quantified chemical mechanisms need more investigation. The positive meteorological feedback noted on PM2.5 mass explains over 70 % of cumulative explosive growth.
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Hayden, K. L., D. M. L. Sills, J. R. Brook, S. M. Li, P. A. Makar, M. Z. Markovic, P. Liu, et al. "Aircraft study of the impact of lake-breeze circulations on trace gases and particles during BAQS-Met 2007." Atmospheric Chemistry and Physics Discussions 11, no. 4 (April 13, 2011): 11497–546. http://dx.doi.org/10.5194/acpd-11-11497-2011.
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Abstract. High time-resolved aircraft data, concurrent surface measurements and air quality model simulations were explored to diagnose the processes influencing aerosol chemistry under the influence of lake-breeze circulations in a polluted region of southwestern Ontario, Canada. The analysis was based upon horizontal aircraft transects at multiple altitudes across an entire lake-breeze circulation. Air mass boundaries due to lake-breeze fronts were identified in the aircraft meteorological and chemical data, which were consistent with the frontal locations determined from surface analyses. Observations and modelling support the interpretation of a lake-breeze circulation where pollutants were lofted at a lake-breeze front, transported in the synoptic flow, caught in a downdraft over the lake, and then confined by onshore flow. The detailed analysis led to the development of conceptual models that summarize the complex 3-D circulation patterns and their interaction with the synoptic flow. The identified air mass boundaries, the interpretation of the lake-breeze circulation, and best estimates for air parcel circulation times in the lake-breeze circulation (1.2 to 3.0 h) enabled formation rates of oxygenated organic aerosol (OOA/ΔCO) and SO42− to be determined. The formation rate for OOA, relative to excess CO, was found to be 2.5–6.2 μg m−3 ppmv−1 h−1 and the SO42− formation rate was 1.8–4.6% h−1. The formation rates are enhanced relative to regional background rates implying that lake-breeze circulations are an important dynamic in the formation of SO42− and secondary organic aerosol. The presence of cumulus clouds associated with the lake-breeze fronts suggests that these enhancements could be due to cloud processes. Additionally, the effective confinement of pollutants along the shoreline may have limited pollutant dilution leading to elevated oxidant concentrations.
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Hayden, K. L., D. M. L. Sills, J. R. Brook, S. M. Li, P. A. Makar, M. Z. Markovic, P. Liu, et al. "Aircraft study of the impact of lake-breeze circulations on trace gases and particles during BAQS-Met 2007." Atmospheric Chemistry and Physics 11, no. 19 (October 10, 2011): 10173–92. http://dx.doi.org/10.5194/acp-11-10173-2011.
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Abstract. High time-resolved aircraft data, concurrent surface measurements and air quality model simulations were explored to diagnose the processes influencing aerosol chemistry under the influence of lake-breeze circulations in a polluted region of southwestern Ontario, Canada. The analysis was based upon horizontal aircraft transects conducted at multiple altitudes across an entire lake-breeze circulation. Air mass boundaries due to lake-breeze fronts were identified in the aircraft meteorological and chemical data, which were consistent with the frontal locations determined from surface analyses. Observations and modelling support the interpretation of a lake-breeze circulation where pollutants were lofted at a lake-breeze front, transported in the synoptic flow, caught in a downdraft over the lake, and then confined by onshore flow. The detailed analysis led to the development of conceptual models that summarize the complex 3-D circulation patterns and their interaction with the synoptic flow. The identified air mass boundaries, the interpretation of the lake-breeze circulation, and the air parcel circulation time in the lake-breeze circulation (3.0 to 5.0 h) enabled formation rates of organic aerosol (OA/ΔCO) and SO42− to be determined. The formation rate for OA (relative to excess CO in ppmv) was found to be 11.6–19.4 μg m−3 ppmv−1 h−1 and the SO42− formation rate was 5.0–8.8% h−1. The formation rates are enhanced relative to regional background rates implying that lake-breeze circulations are an important dynamic in the formation of SO42− and secondary organic aerosol. The presence of cumulus clouds associated with the lake-breeze fronts suggests that these enhancements could be due to cloud processes. Additionally, the effective confinement of pollutants along the shoreline may have limited pollutant dilution leading to elevated oxidant concentrations.
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Niu, Yanqing, Kuihua Han, Ningbo Gao, Liang Wang, and Norbert Miskolczi. "Pollutant Formation and Control during Fuel Thermochemical Conversion." Journal of Chemistry 2020 (November 26, 2020): 1–2. http://dx.doi.org/10.1155/2020/6073439.
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Anchique, Leonardo, Jackson J. Alcázar, Andrea Ramos-Hernandez, Maximiliano Méndez-López, José R. Mora, Norma Rangel, José Luis Paz, and Edgar Márquez. "Predicting the Adsorption of Amoxicillin and Ibuprofen on Chitosan and Graphene Oxide Materials: A Density Functional Theory Study." Polymers 13, no. 10 (May 17, 2021): 1620. http://dx.doi.org/10.3390/polym13101620.
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The occurrence, persistence, and accumulation of antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) represent a new environmental problem due to their harmful effects on human and aquatic life. A suitable absorbent for a particular type of pollutant does not necessarily absorb other types of compounds, so knowing the compatibility between a particular pollutant and a potential absorbent before experimentation seems to be fundamental. In this work, the molecular interactions between some pharmaceuticals (amoxicillin, ibuprofen, and tetracycline derivatives) with two potential absorbers, chitosan and graphene oxide models (pyrene, GO-1, and coronene, GO-2), were studied using the ωB97X-D/6-311G(2d,p) level of theory. The energetic interaction order found was amoxicillin/chitosan > amoxicillin/GO-1 > amoxicillin/GO-2 > ibuprofen/chitosan > ibuprofen/GO-2 > ibuprofen/GO-1, the negative sign for the interaction energy in all complex formations confirms good compatibility, while the size of Eint between 24–34 kcal/mol indicates physisorption processes. Moreover, the free energies of complex formation were negative, confirming the spontaneity of the processes. The larger interaction of amoxicillin Gos, compared to ibuprofen Gos, is consistent with previously reported experimental results, demonstrating the exceptional predictability of these methods. The second-order perturbation theory analysis shows that the amoxicillin complexes are mainly driven by hydrogen bonds, while van der Waals interactions with chitosan and hydrophobic interactions with graphene oxides are modelled for the ibuprofen complexes. Energy decomposition analysis (EDA) shows that electrostatic energy is a major contributor to the stabilization energy in all cases. The results obtained in this work promote the use of graphene oxides and chitosan as potential adsorbents for the removal of these emerging pollutants from water.
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SEMYACHKOV, Alexander, and Victoria POCHECHUN. "ESTIMATION METHODOLOGY OF MINING INDUSTRIAL COMPLEXES IMPACT ON ENVIRONMENT." Sustainable Development of Mountain Territories 13, no. 2 (June 30, 2021): 215–23. http://dx.doi.org/10.21177/1998-4502-2021-13-2-215-223.
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In the work, on the basis of our own field and laboratory studies of the components of the environment, the regularities of the natural and technogenic metal content of the territory of the Middle Urals were established; the mining complex was assessed as a source of pollutant flows into the environment; the formation of flows of pollutants in the environment under the influence of technogenic and mineral formations has been investigated; it is proposed to divide all pollutants, according to their source of entry into the environment, into atmospheric and hydrogenic flows of mining complexes. The problem is that the methodologies for setting maximum permissible emissions (MPE) and normative permissible discharge (NPD) are practically the same. They cover the assessment of the background concentrations of pollutants in the studied media, the assessment of pollution sources, the establishment on the basis of the dilution (mixing) processes of the predicted concentrations (at the border of the sanitary protection zone or in the control section) and the development of the permissible level of the impact of source into the element of the environment in g / h or in t / year with guaranteed quality assurance). Unfortunately, the methodologies used in standardizing the impact of mining and metallurgical complexes on the environment do not take into account a number of aspects, mainly geochemical, which often leads to the formalization of this process with subsequent negative environmental consequences. The objects of research considered in this work were the mining and metallurgical complexes of the Urals, located on its eastern slope in the basin of the river. Tours and including iron ore (the cities of Kachkanar, N. Tagil), copper ore (the cities of Krasnouralsk, Kirovgrad, Pervouralsk) complexes and environmental components (atmosphere, geo-hydro- and biosphere)) within them. The subject of research is the most characteristic ore and associated metals of the Ural deposits: Fe, Cr, Mn, V, Ni, Co, Zn, Cu, Pb, As, Hg, Cd. The aim of the work was to study the flows of pollutants in natural and man-made geosystems of the Middle Urals and to develop a methodological basis for assessing the impact of mining complexes on the environment.
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Zaytsev, Vadim A. "CHEMICAL CONVERSIONS OF REDUCED CARBON COMPOUNDS AND NITROGEN OXIDES IN THE CRAMPED AERODYNAMIC CONDITIONS OF THE URBAN ATMOSPHERE." Bulletin of the Saint Petersburg State Institute of Technology (Technical University) 57 (2021): 111–17. http://dx.doi.org/10.36807/1998-9849-2020-57-83-111-117.
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The kinetics of chemical transformations of the most significant pollutants in the cramped aerodynamic conditions of the urban atmosphere is considered, i.e. in the gaps between rows of wide buildings with significant height. High concentrations created in those areas lead to sufficiently high values of reaction rates. The process is described by a stiff system of differential equations, the solution of which is performed by Rosenbrock method. The effect of reduced carbon compounds and nitrogen oxides in a wide range of their concentrations on the rate of formation of a highly toxic secondary pollutant is investigated. In the course of numerical experiments, conditions are determined that correspond to its maximum value. In that case, the transfer of substances from the reaction zone does not have time to occur.
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Menut, L., B. Bessagnet, D. Khvorostyanov, M. Beekmann, A. Colette, I. Coll, G. Curci, et al. "Regional atmospheric composition modeling with CHIMERE." Geoscientific Model Development Discussions 6, no. 1 (January 21, 2013): 203–329. http://dx.doi.org/10.5194/gmdd-6-203-2013.
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Abstract. Tropospheric trace gas and aerosol pollutants have adverse effects on health, environment and climate. In order to quantify and mitigate such effects, a wide range of processes leading to the formation and transport of pollutants must be considered, understood and represented in numerical models. Regional scale pollution episodes result from the combination of several factors: high emissions (from anthropogenic or natural sources), stagnant meteorological conditions, velocity and efficiency of the chemistry and the deposition. All these processes are highly variable in time and space, and their relative importance to the pollutants budgets can be quantified within a chemistry-transport models (CTM). The offline CTM CHIMERE model uses meteorological model fields and emissions fluxes and calculates deterministically their behavior in the troposphere. The calculated three-dimensional fields of chemical concentrations can be compared to measurements to analyze past periods or used to make air quality forecasts and CHIMERE has enabled a fine understanding of pollutants transport during numerous measurements campaigns. It is a part of the PREVAIR french national forecast platform, delivering pollutant concentrations up to three days in advance. The model also allows scenario studies and long term simulations for pollution trends. The modelling of photochemical air pollution has reached a good level of maturity, and the latest projects involving CHIMERE now aim at increasing our understanding of pollution impact on health at the urban scale or at the other end of the spectrum for long term air quality and climate change interlinkage studies, quantifying the emissions and transport of pollen, but also, at a larger scale, analyzing the transport of pollutants plumes emitted by volcanic eruptions and forest fires.
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Li, Ju, Jielun Sun, Mingyu Zhou, Zhigang Cheng, Qingchun Li, Xiaoyan Cao, and Jingjiang Zhang. "Observational analyses of dramatic developments of a severe air pollution event in the Beijing area." Atmospheric Chemistry and Physics 18, no. 6 (March 20, 2018): 3919–35. http://dx.doi.org/10.5194/acp-18-3919-2018.
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Abstract. A rapid development of a severe air pollution event in Beijing, China, at the end of November 2015 was investigated with unprecedented observations collected during the field campaign of the Study of Urban Rainfall and Fog/Haze (SURF-15). Different from previous statistical analyses of air pollution events and their correlations with meteorological environmental conditions in the area, the role of turbulent mixing in the pollutant transfer was investigated in detail. The analyses indicate that the major pollution source associated with high particulate matter of diameter 2.5 µm (PM2.5) was from south of Beijing. Before the day of the dramatic PM2.5 increase, the nighttime downslope flow from the mountains to the west and north of Beijing reduced the surface PM2.5 concentration northwest of Beijing. The nighttime surface stable boundary layer (SBL) not only kept the relatively less-polluted air near the surface, it also shielded the rough surface from the pollutant transfer by southwesterly winds above the SBL, leading to the fast transport of pollutants over the Beijing area at night. As the daytime convective turbulent mixing developed in the morning, turbulent mixing transported the elevated polluted air downward even though the weak surface wind was from northeast, leading to the dramatic increase of the surface PM2.5 concentration in the urban area. As a result of both turbulent mixing and advection processes with possible aerosol growth from secondary aerosol formation under the low-wind and high-humidity conditions, the PM2.5 concentration reached over 700 µg m−3 in the Beijing area by the end of the day. Contributions of the two transporting processes to the PM2.5 oscillations prior to this dramatic event were also analyzed. The study demonstrates the important role of large-eddy convective turbulent mixing in vertical transfer of pollutants and the role of the SBL in not only decoupling vertical transport of trace gases and aerosols but also in accelerating horizontal transfer of pollutants above.