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Atmospheric composition

Xu Shao, Feng-Min Wu, Hui Yang, Shu-Feng Pang, Yun-Hong Zhang
Although the dicarboxylic acid has been reported to react with nitrate for aged internally mixed aerosols in atmosphere, the quantitative nitrate depletion dependent upon composition in particles is still not well constrained. The chemical composition evolutions for malonic acid/sodium nitrate (MA/SN), malonic acid/magnesium nitrate (MA/MN) and malonic acid/calcium nitrate (MA/CN) particles with the organic to inorganic molar ratio (OIR) of 1:1 are investigated by vacuum Fourier transform infrared spectroscopy (FTIR)...
May 9, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Qing Ye, Peishi Gu, Hugh Z Li, Ellis S Robinson, Eric M Lipsky, Christos Kaltsonoudis, Alex K Y Lee, Joshua Schulz Apte, Allen L Robinson, Ryan Christopher Sullivan, Albert A Presto, Neil M Donahue
Characterizing intra-city variations of atmospheric particulate matter has mostly relied on fixed-site monitoring and quantifying variability in terms of different bulk aerosol species. In this study, we performed ground-based mobile measurements using a single-particle mass spectrometer to study spatial patterns of source-specific particles and the evolution of particle mixing state in 21 areas in the metropolitan area of Pittsburgh, PA. We selected sampling areas based on traffic density and restaurant density with each area ranging from 0...
May 18, 2018: Environmental Science & Technology
Xiancheng Ma, Liqing Li, Ruofei Chen, Chunhao Wang, Haoyang Li, Hailong Li
CO2 adsorption capacity of nitrogen-doped porous carbon depends to a large nitrogen doping levels and high surface area in previous studies. However, it seems difficult to incorporate large amounts of nitrogen while maintaining a high surface area and pore structure. Here we have reported porous carbon having a nitrogen content of up to 25.52% and specific surface area of 948 m2 g-1, which is prepared by pyrolyzing the nitrogen-containing zeolite imidazole framework-8 and urea composite at 650 °C under a nitrogen atmosphere...
May 18, 2018: Chemistry, An Asian Journal
Nasser A M Barakat, Mohannad Alajami, Zafar Khan Ghouri, Saeed Al-Meer
The internal resistances of fuel cells strongly affect the generated power. Basically, in the fuel cell, the anode can be prepared by deposition of a film from the functional electrocatalyst on a proper gas diffusion layer. Accordingly, an interfacial resistance for the electron transport is created between the two layers. Electrocatalyst-functionalized gas diffusion layer (GDL) can distinctly reduce the interfacial resistance between the catalyst layer and the GDL. In this study, NiMn nanoparticles-decorated carbon felt is introduced as functionalized GDL to be exploited as a ready-made anode in a direct urea fuel cell...
May 16, 2018: Nanomaterials
Huanhuan Jiang, Myoseon Jang
The atmospheric process dynamically changes the chemical compositions of organic aerosol (OA), thereby complicating the interpretation of its health effects. In this study, the dynamic evolution of the oxidative potential of various OA was studied, including wood combustion particles and secondary organic aerosols (SOA) generated from different hydrocarbons (i.e. gasoline, toluene, isoprene and α-pinene). The oxidative potential of OA at different aging stages was subsequently measured by the dithiothreitol consumption (DTTm, mass normalized)...
May 17, 2018: Environmental Science & Technology
Thenmozhi Sukumar, Dharmaraj Nallasamy
Poly(vinyl pyrrolidone) (PVP)/copper oxide composite nanofibers were prepared by electrospinning technique using PVP and copper acetate as precursors and calcinated at high temperature to yield polymer free, phase pure copper oxide nanofibers (CuO NFs). The powder X-ray diffraction (XRD) pattern, transmission electron microscopic (TEM) images and selected area electron diffraction pattern (SAED) results showed that the calcinated CuO NFs were crystalline with 166 nm diameter and monoclinic in phase. From the catalytic application point of view, the newly prepared electrospun CuO NFs were tested for N-arylation of imidazole using aryl halides...
January 1, 2018: Journal of Nanoscience and Nanotechnology
Marceau Gresse, Jean Vandemeulebrouck, Svetlana Byrdina, Giovanni Chiodini, Philippe Roux, Antonio Pio Rinaldi, Marc Wathelet, Tullio Ricci, Jean Letort, Zaccaria Petrillo, Paola Tuccimei, Carlo Lucchetti, Alessandra Sciarra
Fumaroles are a common manifestation of volcanic activity that are associated with large emissions of gases into the atmosphere. These gases originate from the magma, and they can provide indirect and unique insights into magmatic processes. Therefore, they are extensively used to monitor and forecast eruptive activity. During their ascent, the magmatic gases interact with the rock and hydrothermal fluids, which modify their geochemical compositions. These interactions can complicate our understanding of the real volcanic dynamics and remain poorly considered...
May 15, 2018: Scientific Reports
Angela Taboada, Javier Calvo-Fernández, Elena Marcos, Leonor Calvo
Elevated atmospheric nitrogen (N) deposition is a major driver of change, altering the structure/functioning of nutrient-poor Calluna vulgaris-heathlands over Europe. These effects amply proven for north-western/central heathlands may, however, vary across the ecosystem's distribution, especially at the range limits, as heathlands are highly vulnerable to land-use changes combined with present climate change. This is an often overlooked and greatly understudied aspect of the ecology of heathlands facing global change...
May 12, 2018: Science of the Total Environment
Jinling Liu, Xiangyang Bi, Fanglin Li, Pengcong Wang, Jin Wu
Concentrations of heavy metals, as well as isotopic compositions of mercury (Hg) and lead (Pb), in mosses (Bryum argenteum) from the Three Gorges Reservoir (TGR) region were investigated to decipher the sources of atmospheric metals in this region. Higher contents of metals (0.90 ± 0.65 mg/kg of Cd, 24.6 ± 27.4 mg/kg of Cu, and 36.1 ± 51.1 mg/kg of Pb) in the mosses from TGR were found compared with those from pollution-free regions. Principal component analysis (PCA) grouped the moss metals into four main components which were associated with both anthropogenic and natural sources...
May 12, 2018: Environmental Pollution
Wolfgang Vautz, Chandrasekhara Hariharan, Maximilian Weigend
Plant volatile organic compounds (pVOCs) are being recognized as an important factor in plant-environment interactions. Both the type and amount of the emissions appear to be heavily affected by climate change. A range of studies therefore has been directed toward understanding pVOC emissions, mostly under laboratory conditions (branch/leaf enclosure). However, there is a lack of rapid, sensitive, and selective analytical methods, and therefore, only little is known about VOC emissions under natural, outdoor conditions...
May 2018: Ecology and Evolution
Michael P Meredith, Ulrike Falk, Anna Valeria Bers, Andreas Mackensen, Irene R Schloss, Eduardo Ruiz Barlett, Kerstin Jerosch, Adrián Silva Busso, Doris Abele
Glacial meltwater discharge from Antarctica is a key influence on the marine environment, impacting ocean circulation, sea level and productivity of the pelagic and benthic ecosystems. The responses elicited depend strongly on the characteristics of the meltwater releases, including timing, spatial structure and geochemical composition. Here we use isotopic tracers to reveal the time-varying pattern of meltwater during a discharge event from the Fourcade Glacier into Potter Cove, northern Antarctic Peninsula...
June 28, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Lianfang Wei, Siyao Yue, Wanyu Zhao, Wenyi Yang, Yingjie Zhang, Lujie Ren, Xiaokun Han, Qingjun Guo, Yele Sun, Zifa Wang, Pingqing Fu
Pervasive particulate pollution has been observed over large areas of the North China Plain. The high level of sulfate, a major component in fine particles, is pronounced during heavy pollution periods. Being different from source apportionments by atmospheric chemistry-transport model and receptor modeling methods, here we utilize sulfur isotopes to discern the potential emission sources. Sixty-five daily PM2.5 samples were collected at an urban site in Beijing between September 2013 and July 2014. Inorganic ions, organic/elemental carbon and stable sulfur isotopes of sulfate were analyzed...
August 15, 2018: Science of the Total Environment
Chris Mehta, Anthony Perez, Glenn Thompson, Matthew A Pasek
A hypothesis in prebiotic chemistry argues that organics were delivered to the early Earth in abundance by meteoritic sources. This study tests that hypothesis by measuring how the transfer of organic matter to the surface of Earth is affected by energy-dissipation processes such as ablation and airbursts. Exogenous delivery has been relied upon as a source of primordial material, but it must stand to reason that other avenues (i.e., hydrothermal vents, electric discharge) played a bigger role in the formation of life as we know it on Earth if exogenous material was unable to deliver significant quantities of organics...
May 12, 2018: Life
Sreejata Bandopadhyay, Lluis Martin-Closas, Ana M Pelacho, Jennifer M DeBruyn
Agricultural plastic mulch films are widely used in specialty crop production systems because of their agronomic benefits. Biodegradable plastic mulches (BDMs) offer an environmentally sustainable alternative to conventional polyethylene (PE) mulch. Unlike PE films, which need to be removed after use, BDMs are tilled into soil where they are expected to biodegrade. However, there remains considerable uncertainty about long-term impacts of BDM incorporation on soil ecosystems. BDMs potentially influence soil microbial communities in two ways: first, as a surface barrier prior to soil incorporation, indirectly affecting soil microclimate and atmosphere (similar to PE films) and second, after soil incorporation, as a direct input of physical fragments, which add carbon, microorganisms, additives, and adherent chemicals...
2018: Frontiers in Microbiology
Yujiao Sun, Shangwei Xu, Danyang Zheng, Jie Li, Hezhong Tian, Yong Wang
In this study, particulate matter (PM) with aerodynamic diameters of ≤2.5 and ≤10 μm (PM2.5 and PM10 , respectively), which was found at different concentrations in spring, was collected in Beijing. The chemical composition and bacterial community diversity of PM were determined, and the relationship between them was studied by 16S rRNA sequencing and mathematical statistics. Chemical composition analysis revealed greater relative percentages of total organic compounds (TOC) and secondary ions (NO3 - , SO4 2- , and NH4 + )...
May 10, 2018: Science of the Total Environment
Bożena Graca, Aleksandra Zgrundo, Danuta Zakrzewska, Monika Rzodkiewicz, Jakub Karczewski
The number, morphology and elemental composition of nanoparticles (<100 nm) in marine water was investigated using Variable Pressure Scanning Electron Microscopy (VP-SEM) and Energy-dispersive X-ray spectroscopy (EDS). Preliminary research conducted in the Baltic Sea showed that the number of nanoparticles in seawater varied from undetectable to 380 (x102 ) cm-3 . Wind mixing and density barriers (thermocline) had a significant impact on the abundance and distribution of nanoparticles in water. Many more nanoparticles (mainly nanofibers) were detected in periods of intensive primary production and thermal stratification of water than at the end of the growing season and during periods of strong wind mixing...
May 5, 2018: Chemosphere
Caiwei Wang, Shouyu Zhang, Shunyan Wu, Zhongyao Cao, Yifan Zhang, Hao Li, Fenghao Jiang, Junfu Lyu
The typical properties and yield of the refined hydrothermolytic acid (RHTA) and refined hydrothermolytic oxidation acid (RHOA) respectively prepared from cotton stalk by the hydrothermolysis process with and without hydrogen peroxide at 180-280 °C were investigated. The pH of RHOA at 180-260 °C is lower than that of RHTA. The yield of RHOA prepared at 180-280 °C is higher than that of RHTA except 230 °C. Besides, the variation trend of RHOA yield at 180-260 °C is in accordance with that of RHTA yield at 200-280 °C...
May 4, 2018: Bioresource Technology
Heather L Moorhouse, Suzanne McGowan, Zofia E Taranu, Irene Gregory-Eaves, Peter R Leavitt, Matthew D Jones, Philip Barker, Susan A Brayshaw
Freshwater ecosystems are threatened by multiple anthropogenic stressors acting over different spatial and temporal scales, resulting in toxic algal blooms, reduced water quality, and hypoxia. However, while catchment characteristics act as a 'filter' modifying lake response to disturbance, little is known of the relative importance of different drivers and possible differentiation in the response of upland remote lakes in comparison to lowland, impacted lakes. Moreover, many studies have focussed on single lakes rather than looking at responses across a set of individual, yet connected lake basins...
May 10, 2018: Global Change Biology
A Masalaite, R Holzinger, D Ceburnis, V Remeikis, V Ulevičius, T Röckmann, U Dusek
Size-segregated aerosol particles were collected during winter sampling campaigns at a coastal (55°37' N, 21°03'E) and an urban (54°64' N, 25°18' E) site. Organic compounds were thermally desorbed from the samples at different temperature steps ranging from 100 °C to 350 °C. The organic matter (OM) desorbed at each temperature step is analysed for stable carbon isotopes using an isotope ratio mass spectrometer (IRMS) and for individual organic compounds using a Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-MS)...
May 7, 2018: Environmental Pollution
Afzal Khan, Viet Huong Nguyen, David Muñoz-Rojas, Sara Aghazadehchors, Carmen Jiménez, Ngoc Duy Nguyen, Daniel Bellet
Silver nanowire (AgNW) networks offer excellent electrical and optical properties and have emerged as one of the most attractive alternatives to transparent conductive oxides to be used in flexible optoelectronic applications. However, AgNW networks still suffer from chemical, thermal and electrical instabilities which in some cases can hinder their efficient integration as transparent electrodes in devices such as solar cells, transparent heaters, touch screens or organic light emitting diodes (OLEDs). We have used atmospheric pressure spatial atomic layer deposition (AP-SALD) to fabricate hybrid transparent electrode materials in which the AgNW network is protected by a conformal thin zinc oxide layer...
May 10, 2018: ACS Applied Materials & Interfaces
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