Literatura académica sobre el tema "Anthropogenic particle"
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Artículos de revistas sobre el tema "Anthropogenic particle"
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Paasonen, Pauli, Kaarle Kupiainen, Zbigniew Klimont, Antoon Visschedijk, Hugo A. C. Denier van der Gon y Markus Amann. "Continental anthropogenic primary particle number emissions". Atmospheric Chemistry and Physics 16, n.º 11 (6 de junio de 2016): 6823–40. http://dx.doi.org/10.5194/acp-16-6823-2016.
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Abstract. Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol–cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening emission regulations. However, there are significant uncertainties in these current emission estimates and the key actions for decreasing the uncertainties are pointed out.
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Russell, Philip A. "The Analyses of Anthropogenic Atmospheric Particulates by EM". Proceedings, annual meeting, Electron Microscopy Society of America 48, n.º 2 (12 de agosto de 1990): 547. http://dx.doi.org/10.1017/s0424820100136349.
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This presentation will summarize fourteen years of research on the physical and chemical nature of particulates suspended in the earths atmosphere utilizing scanning electron microscopy and, to a lesser extent, transmission electron microscopy. Topics to be discussed include (1) the rationale for using electron microscopy to study airborne particulates, (2) methods for collecting airborne particulates, (3) methods of analysis and (4) a summary of results. Examples will demonstrate how conclusions about the nature and source of collected particles can differ between bulk sample analyses and discrete particle analyses. Without the input from discrete particle analyses, bulk analytical techniques may produce serious errors in the apportionment of airborne particulates to specific sources.The scanning electron microscope (SEM) and transmission electron microscopy (TEM) have proven themselves to be the preferred instruments to use in the study of discrete fine particles because they permit sufficient resolution and analytical capabilities to examine the structure and chemistry of individual particles less than a few micrometers in diameter.
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Pawlak, Filip, Krystyna Koziol, Wanda Wilczyńska-Michalik, Mikołaj Worosz, Marek Michalik, Sara Lehmann-Konera y Żaneta Polkowska. "Characteristics of Anthropogenic Pollution in the Atmospheric Air of South-Western Svalbard (Hornsund, Spring 2019)". Water 16, n.º 11 (23 de mayo de 2024): 1486. http://dx.doi.org/10.3390/w16111486.
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The character of atmospheric pollution and its impact on surface waters may vary substantially in space, and hence, we add a potentially important location for the studies of atmospheric air pollution to the map of the High Arctic. We have investigated the anthropogenic particle characteristics and selected persistent organic pollutant concentrations, in a priorly unmonitored location in the Arctic (Svalbard), exposed to a climatic gradient. Single-particle analysis of PM indicates that besides the prevailing natural aerosol particles, anthropogenic ones were present. The likely anthropogenic origin of some particles was established for spherical Fe-rich or aluminosilicate particles formed in high-temperature processes or metal-rich particles of the chemical composition corresponding to industrial products and atypical for natural minerals; soot, tar balls, and secondary sulfate were also likely of anthropogenic origin. Some of the observed anthropogenic particles could only come from remote industrial sources. POP concentrations indicated a background of LRAT, consistent with the ΣPCB concentrations and volatility profile. However, the ΣDDX composition indicating aged sources and an order of magnitude higher concentrations of both ΣDDXs and ΣHCHs than at other High Arctic monitoring stations indicate their potential source in two types of re-emission from secondary sources, i.e., from seawater and snowpack, respectively.
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Bjedov, Dora, Alma Mikuška, Vlatka Gvozdić, Petar Glavaš, Dora Gradečak y Mirta Sudarić Bogojević. "White Stork Pellets: Non-Invasive Solution to Monitor Anthropogenic Particle Pollution". Toxics 12, n.º 4 (23 de marzo de 2024): 236. http://dx.doi.org/10.3390/toxics12040236.
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The present study applied a non-invasive method to analyse anthropogenic particles and prey items in white stork (Ciconia ciconia) pellets. Pellets (n = 20) were obtained from white stork nests during the 2020 breeding season from two sites in Croatia. In total, 7869 anthropogenic particles were isolated. The majority of particles were fragments, while previous studies on other birds often reported fibres. An ATR–FTIR polymer analysis detected glass and construction and building materials, as well as several compounds associated with plastic masses. Polymer investigation revealed the presence of dotriacontane and octacosane, which are by-products of polyethylene (PE) degradation and transformation. Additionally, the detection of vinylidene chloride (VDC) highlights the historical contribution of polyvinylidene chloride (PVDC) to plastic pollution. Significant variation in particle quantity and size between the sampling sites was detected, with larger particles found at sites associated with the metal mechanical engineering industry and agriculture. Prey assessment revealed chitin remains of large insects such as Orthoptera and Coleoptera. This research confirms the potential of pellet analysis as a valuable tool for assessing the presence of anthropogenic particles in the environment. However, further research is needed to fully understand the extent of particle ingestion, particle sources and potential impact.
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Ahlm, L., R. Krejci, E. D. Nilsson, E. M. Mårtensson, M. Vogt y P. Artaxo. "Emission and dry deposition of accumulation mode particles in the Amazon Basin". Atmospheric Chemistry and Physics 10, n.º 21 (3 de noviembre de 2010): 10237–53. http://dx.doi.org/10.5194/acp-10-10237-2010.
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Abstract. Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25–2.5 μm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison. Size-resolved net particle fluxes of the five lowest size bins, representing 0.25–0.45 μm in diameter, were in general dominated by deposition in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. Transfer velocities within this particle size range were observed to increase linearly with increasing friction velocity and increasing particle diameter. In the diameter range 0.5–2.5 μm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net upward fluxes were observed. However, in wind sectors associated with higher anthropogenic influence, deposition fluxes dominated. The net upward fluxes were interpreted as a result of primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The net emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and were best correlated with horizontal wind speed according to the equation log10 F=0.48 · U+2.21 where F is the net emission number flux of 0.5–2.5 μm particles [m−2 s−1] and U is the horizontal wind speed [ms−1] at the top of the tower.
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Xausa, Filippo, Pauli Paasonen, Risto Makkonen, Mikhail Arshinov, Aijun Ding, Hugo Denier Van Der Gon, Veli-Matti Kerminen y Markku Kulmala. "Advancing global aerosol simulations with size-segregated anthropogenic particle number emissions". Atmospheric Chemistry and Physics 18, n.º 13 (16 de julio de 2018): 10039–54. http://dx.doi.org/10.5194/acp-18-10039-2018.
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Abstract. Climate models are important tools that are used for generating climate change projections, in which aerosol–climate interactions are one of the main sources of uncertainties. In order to quantify aerosol–radiation and aerosol–cloud interactions, detailed input of anthropogenic aerosol number emissions is necessary. However, the anthropogenic aerosol number emissions are usually converted from the corresponding mass emissions in pre-compiled emission inventories through a very simplistic method depending uniquely on chemical composition, particle size and density, which are defined for a few, very wide main source sectors. In this work, the anthropogenic particle number emissions converted from the AeroCom mass in the ECHAM-HAM climate model were replaced with the recently formulated number emissions from the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model. In the GAINS model the emission number size distributions vary, for example, with respect to the fuel and technology. Special attention was paid to accumulation mode particles (particle diameter dp > 100 nm) because of (i) their capability of acting as cloud condensation nuclei (CCN), thus forming cloud droplets and affecting Earth's radiation budget, and (ii) their dominant role in forming the coagulation sink and thus limiting the concentration of sub-100 nm particles. In addition, the estimates of anthropogenic CCN formation, and thus the forcing from aerosol–climate interactions, are expected to be affected. Analysis of global particle number concentrations and size distributions reveals that GAINS implementation increases CCN concentration compared with AeroCom, with regional enhancement factors reaching values as high as 10. A comparison between modeled and observed concentrations shows that the increase in number concentration for accumulation mode particles agrees well with measurements, but it leads to a consistent underestimation of both nucleation mode and Aitken mode (dp < 100 nm) particle number concentrations. This suggests that revisions are needed in the new particle formation and growth schemes currently applied in global modeling frameworks.
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Schmidt, Susan, Johannes Schneider, Thomas Klimach, Stephan Mertes, Ludwig Paul Schenk, Piotr Kupiszewski, Joachim Curtius y Stephan Borrmann. "Online single particle analysis of ice particle residuals from mountain-top mixed-phase clouds using laboratory derived particle type assignment". Atmospheric Chemistry and Physics 17, n.º 1 (12 de enero de 2017): 575–94. http://dx.doi.org/10.5194/acp-17-575-2017.
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Abstract. In situ single particle analysis of ice particle residuals (IPRs) and out-of-cloud aerosol particles was conducted by means of laser ablation mass spectrometry during the intensive INUIT-JFJ/CLACE campaign at the high alpine research station Jungfraujoch (3580 m a.s.l.) in January–February 2013. During the 4-week campaign more than 70 000 out-of-cloud aerosol particles and 595 IPRs were analyzed covering a particle size diameter range from 100 nm to 3 µm. The IPRs were sampled during 273 h while the station was covered by mixed-phase clouds at ambient temperatures between −27 and −6 °C. The identification of particle types is based on laboratory studies of different types of biological, mineral and anthropogenic aerosol particles. The outcome of these laboratory studies was characteristic marker peaks for each investigated particle type. These marker peaks were applied to the field data. In the sampled IPRs we identified a larger number fraction of primary aerosol particles, like soil dust (13 ± 5 %) and minerals (11 ± 5 %), in comparison to out-of-cloud aerosol particles (2.4 ± 0.4 and 0.4 ± 0.1 %, respectively). Additionally, anthropogenic aerosol particles, such as particles from industrial emissions and lead-containing particles, were found to be more abundant in the IPRs than in the out-of-cloud aerosol. In the out-of-cloud aerosol we identified a large fraction of aged particles (31 ± 5 %), including organic material and secondary inorganics, whereas this particle type was much less abundant (2.7 ± 1.3 %) in the IPRs. In a selected subset of the data where a direct comparison between out-of-cloud aerosol particles and IPRs in air masses with similar origin was possible, a pronounced enhancement of biological particles was found in the IPRs.
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Spracklen, D. V., K. J. Pringle, K. S. Carslaw, G. W. Mann, P. Manktelow y J. Heintzenberg. "First comparison of a global microphysical aerosol model with size-resolved observational aerosol statistics". Atmospheric Chemistry and Physics Discussions 6, n.º 5 (21 de septiembre de 2006): 8871–915. http://dx.doi.org/10.5194/acpd-6-8871-2006.
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Abstract. A statistical synthesis of marine aerosol measurements from experiments in four different oceans is used to evaluate a global aerosol microphysics model (GLOMAP). We compare the model against observed size resolved particle concentrations, probability distributions, and the temporal persistence of different size particles. We attempt to explain the observed size distributions in terms of sulfate and sea spray and quantify the possible contributions of anthropogenic sulfate and carbonaceous material to the number and mass distribution. The model predicts a bimodal size distribution that agrees well with observations as a grand average over all regions, but there are large regional differences. Notably, observed Aitken mode number concentrations are more than a factor 10 higher than in the model for the N Atlantic but a factor 7 lower than the model in the NW Pacific. We also find that modelled Aitken mode and accumulation mode geometric mean diameters are generally smaller in the model by 10–30%. Comparison with observed free tropospheric Aitken mode distributions suggests that the model underpredicts growth of these particles during descent to the MBL. Recent observations of a substantial organic component of free tropospheric aerosol could explain this discrepancy. We find that anthropogenic continental material makes a substantial contribution to N Atlantic marine boundary layer (MBL) aerosol, with typically 60–90% of sulfate across the particle size range coming from anthropogenic sources, even if we analyse air that has spent an average of >120 h away from land. However, anthropogenic primary black carbon and organic carbon particles do not explain the large discrepancies in Aitken mode number. Several explanations for the discrepancy are suggested. The lack of lower atmospheric particle formation in the model may explain low N Atlantic particle concentrations. However, the observed and modelled particle persistence at Cape Grim in the Southern Ocean, does not reveal a diurnal cycle consistent with a photochemically driven local particle source. We also show that a physically based cloud drop activation scheme is needed to explain the observed change in accumulation mode geometric mean diameter with particle number.
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Ahlm, L., R. Krejci, E. D. Nilsson, E. M. Mårtensson, M. Vogt y P. Artaxo. "Emission and deposition of accumulation and coarse mode particles in the Amazon basin". Atmospheric Chemistry and Physics Discussions 10, n.º 6 (8 de junio de 2010): 14013–52. http://dx.doi.org/10.5194/acpd-10-14013-2010.
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Abstract. Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25–2.5 μm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison. Size-resolved net particle fluxes of the five lowest size bins, representing 0.25–0.45 μm in diameter, pointed downward in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. In the diameter range 0.5–2.5 μm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net emission fluxes dominated. However, in wind sectors associated with higher anthropogenic influence, net deposition fluxes dominated. The net emission fluxes were interpreted as primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and these emissions were best correlated with horizontal wind speed by the equation log10F=0.47·U+2.26 where F is the emission number flux of 0.5–2.5 μm particles [m−2s−1] and U is the horizontal wind speed [ms−1] at the top of the tower.
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Bateman, Adam P., Zhaoheng Gong, Tristan H. Harder, Suzane S. de Sá, Bingbing Wang, Paulo Castillo, Swarup China et al. "Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest". Atmospheric Chemistry and Physics 17, n.º 3 (6 de febrero de 2017): 1759–73. http://dx.doi.org/10.5194/acp-17-1759-2017.
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Abstract. The occurrence of nonliquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 and IOP2) that took place during the wet and dry seasons of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional- and continental-scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, an indicator of physical state, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopy confirmed that liquid particles adhered, while nonliquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95 % of the particles adhered as a campaign average. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, produces liquid PM over this tropical forest. During periods of anthropogenic influence, by comparison, the rebound fraction dropped to as low as 60 % at 95 % RH. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of nonliquid PM at high RH correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70 % of the variance in the observed rebound fractions. Anthropogenic influences can contribute to the presence of nonliquid PM in the atmospheric particle population through the combined effects of molecular species that increase viscosity when internally mixed with background PM and increased concentrations of nonliquid anthropogenic particles in external mixtures of anthropogenic and biogenic PM.
Tesis sobre el tema "Anthropogenic particle"
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Schoone, Marion. "Effect of organic matter on sorption of polycyclic aromatic hydrocarbons interaction with natural soils, soils containing anthropogenic organic matter, anthropogenic organic materials and particle size fractions from soils /". [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=96193400X.
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Amos, Helen Marie. "Toward an improved understanding of the global biogeochemical cycle of mercury". Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11493.
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Mercury (Hg) is a potent neurotoxin, has both natural and anthropogenic sources to the environment, and is globally dispersed. Humans have been using Hg since antiquity and continue its use in large quantities, mobilizing Hg from stable long-lived geologic reservoirs to actively cycling surface terrestrial and aquatic ecosystems. Human activities, such as mining and coal combustion, have perturbed the natural biogeochemical cycle of Hg. However, the distribution of natural versus anthropogenic Hg in the environment today and the extent of anthropogenic perturbation (i.e., enrichment) are uncertain. Previous model estimates of anthropogenic enrichment have been limited by a lack of information about historical emissions, examined only near-term effects, or have not accounted for the full coupling between biogeochemical reservoirs. Presented here is a framework that integrates recently available historical emission inventories and overcomes these barriers, providing an improved quantitative understanding of global Hg cycling.Earth and Planetary Sciences
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Horchler, Eva Johanna. "Secondary organic aerosol formation in a smog chamber using ambient urban air as a matrix component". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/235930/1/Eva%2BJohanna%2BHorchler%2BThesis%282%29.pdf.
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In urban environments, a significant portion of atmospheric aerosols are of organic composition with the secondary organic aerosol (SOA) fraction being one of the most important but least understood. This work examines SOA production in a smog chamber using a-pinene and isoprene as biogenic precursors and particle-free ambient urban air as anthropogenic emissions. The observations revealed that the SOA formation is controlled by the components present in the matrix and a-pinene or isoprene affect the reaction processes in such a way that the SOA concentration is either increased or decreased.
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Lefebvre, Charlotte. "Distribution spatiale et temporelle des microplastiques et particules anthropiques au sein d'une lagune côtière mésotidale, le Bassin d'Arcachon. Approche multi-compartiments". Electronic Thesis or Diss., Bordeaux, 2022. http://www.theses.fr/2022BORD0230.
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Le plastique est un matériel peu cher, léger et résistant, ce qui l’a rendu rapidement indispensable dans tous types de secteurs tel que celui de l’emballage alimentaire, du médicale ou encore de l’automobile et du bâtiment. Néanmoins, ces extraordinaires propriétés ont aussi contribué à son actuelle omniprésence dans l’environnement marin, de manière parfois insidieuse. En effet, une fraction souvent invisible à l’œil nu, nommée microplastique (MP) est aujourd’hui étudiée avec intérêt. Les MP sont principalement définis par une taille inférieure à 5 mm, bien que la limite inférieure soit encore discutée au sein de la communauté. Dans le même temps, d’autres types de particules manufacturées par l’homme sont de plus en plus fréquemment décrites, tel que des fragments caoutchouteux noirs ou des fibres. Ces particules anthropiques (AP), MP inclus, ont été détectées dans l’ensemble des compartiments aquatiques (e.g. eau de surface et colonne d’eau) et le compartiment sédimentaire (e.g. plages, sédiments subtidaux et intertidaux) et dans un grand nombre d’espèces dans toutes les régions océaniques. Cependant, leur présence n’est pas anodine car les MP peuvent modifier certains cycles géochimiques, mais aussi biologiques. Par exemple, du fait de leur petite taille, ils peuvent interagir avec une très large gamme d’espèces aquatiques allant du zooplancton aux cétacés. Hors, dans le Bassin d’Arcachon, une pression anthropique importante découle de l’attractivité et de la richesse de cette lagune (e.g. pêche, conchyliculture et tourisme). Par ailleurs, ce système lagunaire est complexe de par sa morphologie (e.g. chenaux et zones intertidales) et son fonctionnement hydrodynamique est marqué principalement par les marées. Ainsi, ce projet de recherche doctoral a permis d’établir un état des lieux de la contamination par les MP et autres particules anthropiques au sein du Bassin d’Arcachon (notamment des fibres). Plus particulièrement, nous avons 1) quantifié et caractérisé les AP et MP présents dans différents compartiments de cette lagune (eau de surface, colonne d’eau, sédiment intertidaux, laisse de mer, organismes aquatiques), 2) déterminé leur distribution spatiale (depuis la zone océanique jusqu’aux limites continentales du bassin) et exploré la dynamique de leur transport entre les compartiments, 3) caractérisé l’évolution temporelle de la contamination au sein de ces compartimentsAs a cheap, light and resistant material, plastic rapidly became unavoidable in many sectors such as packaging, medical, automobile or building ones. However, theses extraordinary properties contribute to its ubiquity in marine environments, and sometime in an insidious way. Indeed, there is a fraction invisible to the naked eyes, named microplastic (MP), that draw researchers’ attention. They are commonly described by an upper limit size of 5 mm, yet the lower size limit is still under discussion. Meantime, other types of manufactured particles are more and more described, such as black rubbery fragments and fibers. These anthropogenic particles (AP) were already detected in marine compartments of all regions, from sea surface to bottom sediments by the way of beach, water column and living organisms. Nevertheless, MP contamination could be associated to impairment of geochemical cycles and biologic ones. Actually, because they are small-sized, MP can be ingested by a wide range of marine organisms (from zooplankton to cetacean). Additionally, the Arcachon Bay area supports important and diverse anthropogenic activities such as fishing, shellfish farming and mass tourism. Additionally, the lagoon have a complex morphology (e.g. intertidal areas and passes) and its hydrodynamic is mainly driven by tide. Thus, this project describes AP and MP contaminations in the Arcachon Bay, such as the one caused by fibers. Specifically, we were able to 1) quantify and characterize AP and MP contamination in nine compartments of this lagoon (sea surface, water column, wastewater effluent, intertidal sediment, high tide line, marine species), 2) describe their spatial distribution (from the oceanic zone to the inner-bay part) and explore transport dynamic between compartments, 3) characterize temporal evolution of the contamination within the studied compartments
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Peña, Sanchez Carlos Alberto. "Quantification of Anthropogenic and Natural Sources of Fine Particles in Houston, Texas Using Positive Matrix Factorization". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc149652/.
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Texas, due to its geographical area, population, and economy is home to a variety of industrialized areas that have significant air quality problems. These urban areas are affected by elevated levels of fine particulate matter (PM2.5). The primary objective of this study was to identify and quantify local and regional sources of air pollution affecting the city of Houston, Texas. Positive Matrix Factorization (PMF) techniques were applied to observational datasets from two urban air quality monitoring sites in Houston from 2003 through 2008 in order to apportion sources of pollutants affecting the study region. Data from 68 species for Aldine and 91 for Deer Park were collected, evaluated, and revised to create concentration and uncertainty input files for the PMF2 and EPA PMF (PMF3) source apportionment models. A 11-sources solution for Aldine and 10-sources for Deer Park were identified as the optimal solutions with both models. The dominant contributors of fine particulate matter in these sites were found to be biomass burnings (2%-8.9%), secondary sulfates I (21.3%-7.6%) and II (38.8%-22.2%), crustal dust (8.9%-10.9%), industrial activities (10.9%-4.2%), traffic (23.1%-15.6%), secondary nitrates (4.4%-5.5%), fresh (1%-1.6%) and aged(5.1%-4.6%) sea salt and refineries (1.3%-0.6%), representing a strong case to confirm the high influence of local activities from the industrial area and the ship channel around the Houston channel. Additionally, potential source contribution function (PSCF) and conditional probability function (CPF) analyses were performed to identify local and regional source-rich areas affecting this urban airshed during the study period. Similarly, seasonal variations and patterns of the apportioned sources were also studied in detail.
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Shaw, Kelly Ann. "Assessing Two Centuries of Anthropogenic Impacts on Silver Lake, Summit County, Ohio". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1365692437.
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Wik, Maria. "Environmental records of carbonaceous fly-ash particles from fossil-fuel combustion". Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 1992. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-110675.
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Fossil fuel combustion produces fly-ash particles that are released into the atmosphere and deposited in the environment. A particularly characteristic kind of fly-ash is spheroidal carbonaceous particles. They are composed of an amorphous carbon matrix in which other elements are dispersed. The elemental carbon content makes them very resistant to chemical degradation and these particles can be relatively easily extracted from sediment and soil samples using a method described in this thesis. The distribution of spheroidal carbonaceous particles in lake sediment profiles, surface sediments and forest soils has been studied. Cores from several Swedish lakes have been analysed and, although the lakes are from different parts of the country, consistent trends in the deposition of the carbonaceous particles have been found. The analyses of dated cores show that the carbonaceous particle deposition in the sediments follows the same general pattern as statistics for Swedish coal and oil combustion over the last two centuries. This indicates that the sediment records reflect the history of the atmospheric deposition of particulate pollutants from fossil fuel combustion. Analysis of surface sediment samples provides an integrated picture of the deposition over the preceding few years and can be used to indicate the contemporary geographical pattern of deposition from the atmosphere. Two sets of surface sediment samples (0-1 cm) were analysed. One comprised samples from 66 lakes around Sweden's second largest city, Gothenburg, and showed very high carbonaceous particle concentrations within a distance of 50 to 100 km from the city. The second set comprised surface sediment samples from 114 lakes distributed all over Sweden. This survey of Sweden demonstrated a geographical north-south gradient with more than a hundred times higher particle concentrations in the south than in the north. This distribution is similar to the distribution of other air pollutants (data obtained from a moss survey and an air monitoring program) and suggests that carbonaceous particles in palaeolimnological investigations of air pollution, can be used as tracers for pollutants that are otherwise difficult to determine in lake sediments. Spheroidal carbonaceous particles also accumulate in soils, and forest soil samples can be used for geographical surveys of particle deposition. In Swedish podzol soils the particles mainly accumulate in the thin organic horizon and concentrations in this layer reflect the total deposition since industrialisation, although most will have been deposited during the last few decades. Since the spheroidal carbonaceous particle record in Swedish lake sediments has a characteristic temporal pattern, carbonaceous particle profiles can be used for indirect dating of recent sediment cores. Analyses of multiple sediment cores from three lakes demonstrate that carbonaceous particles can also be used for studies of sediment distribution in lake basins. Results from Gårdsjön indicate that the acidification of the lake changed sediment distribution processes from a normal sediment focusing regime to a more even distribution of sediments over the lake bottom. Liming of the lake seems to have restored normal sedimentation processes.Diss. (sammanfattning) Umeå : Umeå universitet, 1992, Härtill 8 uppsatser
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Mitchell, Stephanie Bianca. "Sediment Dispersal Processes and Anthropogenic Impacts at Rex Lake, Summit County, Ohio". University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1442416877.
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Pérez, Grau Laura. "The urban health effects and impact of anthropogenic and natural air pollution". Doctoral thesis, Universitat Pompeu Fabra, 2009. http://hdl.handle.net/10803/7195.
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The differential role that airborne particulate matter (PM) size fractions, sources, and components play in producing adverse health effects is not fully understood. Specific gaps include the role of PM generated by traffic and the effects of PMs generated by natural sources. Source specific air pollution epidemiological research still lacks integration in the risk assessment process, a fundamental tool to inform policy makers and the public about the current situation or the impact of future or past air pollution policies. This thesis addresses both these gaps. To explore the effects of PM from different sources, we investigated the association between different PM size fractions and mortality in Barcelona, Spain and used PM chemical composition data to help determine the different sources and components linked to toxicity. To illustrate that local air pollution risk assessments are useful tools in evidence-based public health, we estimated the health and economic benefits that would result from different scenario of improved air quality in the Barcelona metropolitan area and in two communities of Southern California. These case studies include new methods to integrate into the risk assessment process the recent epidemiological evidence related to the effects of traffic exposure.This thesis contributes to a better understanding of the link between particulate matter size fraction, sources, and components and health effects, and to improve air pollution health impact assessment methods. Both contributions have important implications for public health and air pollution public policy.El papel diferencial en que las diferentes fracciones de partículas en suspensión en el aire (PMs), sus fuentes y componentes producen efectos adversos para la salud no está completamente entendido. Las lagunas actuales incluyen el papel de las PMs generadas por el tráfico y los efectos de las PMs generadas por fuentes naturales. La investigación epidemiológica relacionada con fuentes todavía falta ser integrada en el proceso de evaluación de impacto, una herramienta fundamental para informar a los tomadores de decisiones y el público sobre la situación actual o el impacto de futuras o pasadas políticas de contaminación atmosférica. Esta tesis trata estas áreas. Para explorar el papel de las PMs generadas por diferentes fuentes, se ha investigado la asociación entre diferentes fracciones de PMs y mortalidad en Barcelona (España) y se ha usado datos de composición química de PMs para identificar las fuentes y los componentes relacionados con la toxicidad. Para ilustrar que las evaluaciones de impacto a nivel local son herramientas útiles en salud pública, se ha estimado el beneficio en salud y económico que resultaría de diferentes escenarios de mejora de la calidad del aire en el área metropolitana de Barcelona y en dos comunidades de California del Sur. Estos estudios de casos incluyen nuevos métodos para integrar en las evaluaciones de impacto las nuevas evidencias epidemiológicas que relacionan la exposición al tráfico con los efectos en salud. Esta tesis contribuye a un mayor entendimiento del vínculo entre las fracciones de PM, sus fuentes y componentes y los efectos en salud así como a la mejora de los métodos de las evaluaciones de impacto. Estas contribuciones tienen importantes implicaciones para la salud pública y las políticas públicas de contaminación atmosférica.
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Pears, Ben. "The nature, distribution and significance of amended and anthropogenic soils on old arable farms and the elemental analysis of black carbonised particles". Thesis, University of Stirling, 2009. http://hdl.handle.net/1893/2291.
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Ever since the development of farming humans have been implicitly linked with the landscape. Influences include the manipulation of natural environments by woodland clearance, field developments and animal husbandry. Development can also be determined by the identification and distribution of soils developed and modified by the addition of organic and inorganic components. Anthropogenic or amended soils have been identified in many forms across north west Europe that retain distinctive physical and chemical indications of historical agrarian and settlement history. This thesis researched the on-site distribution of anthropogenic and amended soils across different landuse areas and identified and quantified a range of black carbonised particles in order to investigate their role in the soils ability to retain high elemental concentrations of manuring and elements associated with domestic activity and industrial processes. Three sites in contrasting environments were chosen for analysis; in Fair Isle, the Netherlands and Ireland on the basis of an excellent agararian and settlement history and previous analysis of anthropogenic soils. The fieldwork results showed extremly deep plaggen soils in the Netherlands but considerably shallower horizons of amended arable soils on Fair Isle and in Ireland contrary to previous analysis. There was however, clear evidence of a reduction in anthropogenic and amended soils with increased distance from the farm centres as a result of less manuring. The soil pH, organic matter, particle size, magnetic susceptibility and bulk elemental analysis results showed unexpected increases in the amended soils of Fair Isle and Ireland and reflected a similar manuring process. In the Netherlands the deep plaggen soils had very low results reflecting modern arable farming. The micromorphology results illustrated distinctive characteristics associated with localised manuring techniques. On Fair Isle and in Ireland the main organic manuring material was peat and burnt peat, whereas in the Netherlands the plaggen soils were predominantly composed of meadowland and heathland turf. At all three sites there was a large number of black carbonised and black amorphous inclusions and point counting and image analysis results showed a decrease with depth and distance from settlement nucleii mirroring the fieldwork observations. The elemental analysis conducted has proved to be an extremly useful tool for the identification of various forms of black carbon and for identifying the provenance of high elemental concentrations. The oxygen:carbon ratios confirmed the origins of organic components used in the development of the amended and anthropogenic soils and the elemental analysis showed that at each site over 80% of visually unidentifiable amorphous black carbon particles were heavily decomposed carbonised inclusions. Overall the elemental concentrations within the black carbonised particles was very low but this reflected the elemental results found in the bulk soils and the inclusions contained higher concentrations of P, Ca, K, Fe and Al and considerably lower concentrations of elements associated with domestic activity or industry Zn, Cu, Ba, Cr, As and Pb.
Capítulos de libros sobre el tema "Anthropogenic particle"
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Hale, Robert C., Meredith E. Seeley, Ashley E. King y Lehuan H. Yu. "Analytical Chemistry of Plastic Debris: Sampling, Methods, and Instrumentation". En Microplastic in the Environment: Pattern and Process, 17–67. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-78627-4_2.
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AbstractApproaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include tire wear, paint chips, semisynthetics (e.g., rayon), and bioplastics. Plastics commonly contain chemical additives and fillers, which may alter their toxicological potency, behavior (e.g., buoyancy), or detector response (e.g., yield fluorescence) during analysis. Field sampling methods often focus on >20 μm and even >300 μm sized particles and will thus not capture smaller microplastics (which may be most abundant and bioavailable). Analysis of a limited subgroup (selected polymer types, particle sizes, or shapes) of microplastics, while often operationally necessary, can result in an underestimation of actual sample content. These shortcomings complicate calls for toxicological studies of microplastics to be based on “environmentally relevant concentrations.” Sample matrices of interest include water (including wastewater, ice, snow), sediment (soil, dust, wastewater sludge), air, and biota. Properties of the environment, and of the particles themselves, may concentrate plastic debris in select zones (e.g., gyres, shorelines, polar ice, wastewater sludge). Sampling designs should consider such patchy distributions. Episodic releases due to weather and anthropogenic discharges should also be considered. While water grab samples and sieving are commonplace, novel techniques for microplastic isolation, such as continuous flow centrifugation, show promise. The abundance of nonplastic particulates (e.g., clay, detritus, biological material) in samples interferes with microplastic detection and characterization. Their removal is typically accomplished using a combination of gravity separation and oxidative digestion (including strong bases, peroxide, enzymes); unfortunately, aggressive treatments may damage more labile plastics. Microscope-based infrared or Raman detection is often applied to provide polymer chemistry and morphological data for individual microplastic particles. However, the sheer number of particles in many samples presents logistical hurdles. In response, instruments have been developed that employ detector arrays and rapid scanning lasers. The addition of dyes to stain particulates may facilitate spectroscopic detection of some polymer types. Most researchers provide microplastic data in the form of the abundances of polymer types within particle size, polymer, and morphology classes. Polymer mass data in samples remain rare but are essential to elucidating fate. Rather than characterizing individual particles in samples, solvent extraction (following initial sample prep, such as sediment size class sorting), combined with techniques such as thermoanalysis (e.g., pyrolysis), has been used to generate microplastic mass data. However, this may obviate the acquisition of individual particle morphology and compositional information. Alternatively, some techniques (e.g., electron and atomic force microscopy and matrix-assisted laser desorption mass spectrometry) are adept at providing highly detailed data on the size, morphology, composition, and surface chemistry of select particles. Ultimately, the analyst must select the approach best suited for their study goals. Robust quality control elements are also critical to evaluate the accuracy and precision of the sampling and analysis techniques. Further, improved efforts are required to assess and control possible sample contamination due to the ubiquitous distribution of microplastics, especially in indoor environments where samples are processed.
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H. Arp, Hans Peter y Kai-Uwe Goss. "Sorption of Anthropogenic Organic Compounds to Airborne Particles". En Biophysico-Chemical Processes of Anthropogenic Organic Compounds in Environmental Systems, 113–47. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470944479.ch5.
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Paliukh, B. V. y I. I. Zykov. "Method for Recognizing Anthropogenic Particles in Complex Background Environments". En Advances in Intelligent Systems and Computing, 678–87. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-50097-9_69.
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Pignatello, Joseph J. "Interaction of Anthropogenic Organic Chemicals with Organic Matter in Natural Particles". En Molecular Environmental Soil Science at the Interfaces in the Earth’s Critical Zone, 181. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-05297-2_53.
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Seleznev, Andrian A., Ilia V. Yarmoshenko, Georgy P. Malinovsky, Daria Kiseleva, Lyubov V. Leonova, Elena M. Baglaeva y Ekaterina O. Ilgasheva. "Anthropogenic Particles in Contemporary Surface Dirt Sediments in an Urban Environment". En Springer Proceedings in Earth and Environmental Sciences, 221–27. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-00925-0_33.
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Pignatello, Joseph J. "Interactions of Anthropogenic Organic Chemicals with Natural Organic Matter and Black Carbon in Environmental Particles". En Biophysico-Chemical Processes of Anthropogenic Organic Compounds in Environmental Systems, 1–50. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470944479.ch1.
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Ilgasheva, Ekaterina O., Ilya V. Yarmoshenko, Georgy P. Malinovskiy y Andrian A. Seleznev. "Anthropogenic Particles in the Snow Cover in the Area of the Ice Race Track". En Springer Proceedings in Earth and Environmental Sciences, 79–88. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-49468-1_11.
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Garrison, Ervan G. "Geoarchaeology Underwater and Its Challenges". En New Directions in the Search for the First Floridians, 175–93. University Press of Florida, 2019. http://dx.doi.org/10.5744/florida/9781683400738.003.0011.
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This chapter examines, in detail, the Geoarchaeological methods for both predicting and interpreting sites subjected to anthropogenic activities and taphonomic processes specific to inundated contexts. Garrison and Hale show that sediment particle-size, grain-size, and point-count studies coupled with debitage/micro-debitage analyses isolate middens deposits from those of natural origin. Chemical, faunal (primarily vertebrate), and floral proxies for anthropogenic activities were lacking, but they related the nature on inundated sites in a marine environment. The authors discuss how sea-level rise is coupled with these factors.
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Hill, P. S. y I. N. McCave. "Suspended Particle Transport in Benthic Boundary Layers". En The Benthic Boundary Layer, 78–103. Oxford University PressNew York, NY, 2001. http://dx.doi.org/10.1093/oso/9780195118810.003.0004.
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Abstract Benthic boundary layer (BBL) transport of suspended sediment and associated substances, such as organic carbon, nutrients, and anthropogenic contaminants, represents a highly effective mechanism of dispersal. As such, developing predictive understanding of suspended sediment transport has been the goal of sedimentologists, ecologists, and engineers for decades. The goal of this chapter is not to offer a broad, necessarily synoptic view of the current state of knowledge, but rather to highlight several areas of suspended sediment research in BBLs where exciting recent advances have occurred. Featured are processes that affect vertical profiles of suspended sediment in unidirectional, horizontally uniform flows. Consequently, oscillatory flows and controls on the magnitude and timing of transport events are neglected. The assumed simple flow maintains focus on particles. That said, the approaches to parameterizing suspended particle profiles covered in this chapter are general and can be applied to more complex flows of variable strength, frequency, and duration.
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V. Lasareva, Elena y Aksana M. Parfenova. "Influence of Organic Matter on the Transport of Mineral Colloids in the River-Sea Transition Zone". En Oceanography - Relationships of the Oceans With the Continents, Their Biodiversity and the Atmosphere [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.110247.
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The River-Sea Transition Zone has a significant impact on marine ecosystems, especially at present, due to increased anthropogenic pressure on rivers. The colloidal form of river runoff has not been practically studied, unlike the dissolved and suspended one, but this form is particularly important for the transport of river substances. The mechanisms of substance transfer were studied using model systems (colloidal clay, Fe(OH)3 sol), particle aggregation was estimated by changes in optical density, turbidity and particle size. The influence of the nature of dissolved organic matter (DOM) and salinity on colloid transport was studied. It was found that humic substances (HS) (recalcitrant DOM) stabilize mineral colloids with increasing salinity, while their interaction with chitosan (labile DOM) promotes flocculation and further precipitation in the mixing zone. In natural conditions, labile DOM can be released during viral lysis of bacteria or salt stress of biota. It was shown that clay particles modified with HS are flocculated more effectively than pure clays. HS can facilitate the transport of Fe(OH)3 into the outer part of the mixing zone even in the presence of flocculants. The flocculation mechanism and modern views on this process are considered.
Actas de conferencias sobre el tema "Anthropogenic particle"
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Dergunov, A. V. y O. E. Yakubailik. "Analysis of the influence of temperature inversions on the ecological situation in Krasnoyarsk". En Spatial Data Processing for Monitoring of Natural and Anthropogenic Processes 2021. Crossref, 2021. http://dx.doi.org/10.25743/sdm.2021.27.58.051.
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The paper analyzes the meteorological conditions in the city of Krasnoyarsk in the period from January 1, 2019, to December 31, 2020. The relationship between temperature inversions in the surface layer of the atmosphere and air pollution by suspended solid particles PM25 is investigated. The paper uses a set of meteorological data of the NCEP GFS weather forecast model on the air temperature on three isobaric surfaces of 1000, 925, and 850 Mb; on wind gusts and the height of the atmospheric boundary layer. Data on PM25 solid particle concentrations and wind speed are provided by the air monitoring system of the KSC SB RAS. The relationship between the presence of temperature inversions in the lower layer of the atmosphere and periods of significant air pollution is shown, as well as the dependence of changes in wind speed and the height of the boundary layer of the atmosphere with changes in the average daily PM25 concentration. The results of the data analysis allow us to conclude that there is a high degree of correlation between these parameters. The possibility of using the meteorological data of the NCEP GFS model to study the surface layer of the atmosphere and the periods of its pollution, predicting the deterioration of the environmental situation in Krasnoyarsk, is demonstrated.
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Shanley, Kevin T., Goodarz Ahmadi, Philip K. Hopke y Yung-Sung Cheng. "Fibrous and Spherical Particle Transport and Deposition in the Human Nasal Airway: A Computational Fluid Dynamics Model". En ASME 2009 Fluids Engineering Division Summer Meeting. ASMEDC, 2009. http://dx.doi.org/10.1115/fedsm2009-78204.
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As the interface between the human respiratory system and the environment, the nose plays many vital roles. Not the least of which is filter. Resulting from numerous natural and anthropogenic processes, particulate matter becomes airborne. Should particulate matter reach the lower portions of the respiratory tract, a host of maladies may occur. In an attempt to further understand the physics behind particulate matter transitioning from the environment into humans a computational model has been developed to predict the efficiency with which human noses can remove particles before they reach the lungs. To this end computational fluid dynamics and Lagrangian particle tracking simulations have been run to gather information on the deposition behavior of both fibrous and spherical particles. MRI data was collected from the left and right passages of a 181.6 cm, 120.2 kg, human male. The two passages were constructed into separate computational volumes consisting of approximately 950,000 unstructured tetrahedral cells each. A steady laminar flow model was used to simulate the inhalation portion of a human breathing cycle. Volumetric flow rates were varied to represent the full range of human nasal breathing. General agreement was shared quantitatively and qualitatively with previously published in vitro studies on other nasal models. Lagrangian particle tracking was performed for varying sizes of fibrous and spherical particles. Deposition efficiency was shown to increase with fiber aspect ratio, particle size, and flow rate. Anatomy was also identified as effecting deposition.
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Zhao, Yinlin, Hongjie Wen, Bing Ren, Guoyu Wang y Yongxue Wang. "An Improved SPH Model for Simulating Hydrodynamic Consequences Induced by Reef Degradation". En ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18520.
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Abstract Coral reefs degradation accelerates in recent decades due to the natural disturbance and anthropogenic activities. It is important to predict and evaluate reasonably the hydrodynamic consequences of reef degradation. An improved weakly compressible smoothed particle hydrodynamic (WCSPH) porous model is developed based on the standard two-phase mixture theory. The developed WCSPH mixture model is validated by comparing the predicted results with the corresponding available data. The model is then adopted to predict the effects of reef degradation on the spatial distributions of wave setup, wave-induced current and low frequency wave energy over the reef-flat under the reef resonance conditions.
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Kayombo, Gracia y Michel Kalenga Wa Kalenga. "PALM NUTSHELL BIOCHAR QUALITY CORRELATION WITH PYROLYSIS RESIDENCE TIME". En 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022v/4.2/s18.12.
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The global warming and climate change caused by the anthropogenic activities is expected to increase. To address these issues, one key solution is the utilization of renewable materials such as biomass. Biochar, made from biomass materials is seen as a potential option to replace the fossil fuel-based reductants. Pyrolysis is the most common way of producing biochar. However, the physicochemical properties of biochar are significantly influenced by virgin biomass characteristics and the pyrolysis condition such as the temperature, heating rate, residence time. This paper investigates the impact of pyrolysis residence time on the biochar quality produced from raw palm nutshells. In this study, all the experiments were performed at 800 -C, while the time from 30, 40, 45, 50 and 60 mins and the particle size of the raw material varied from 5, 8, 12, 15 to 19mm. A correlation between the fixed carbon content and pore size was established. The different biochar produced were further characterized using proximate analysis and SEM-EDS to evaluate the fixed carbon content and study the changes in the biochar microstructure and pore size of each biochar produced.
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Nakata, M. "Natural and anthropogenic particles over East Asia". En SPIE Remote Sensing, editado por Adolfo Comerón, Evgueni I. Kassianov, Klaus Schäfer, Richard H. Picard, Karin Stein y John D. Gonglewski. SPIE, 2014. http://dx.doi.org/10.1117/12.2066109.
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Pothana, Prasad, Ghoulem Ifrene, Kegang Ling y Fernando E. Garcia. "Investigating Grain Size Influence on the Stress-Dependent Permeability of Porous Rocks Using Particulate Discrete Element Method". En 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0827.
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ABSTRACT Reservoir in-situ stresses continuously evolve during the reservoir life cycle because of the production of hydrocarbons, injection of water and CO2 for enhanced oil recovery, storage of CO2, and nuclear waste disposal. The induced changes to the stress state deform the reservoir rock, including the pores and fractures in the rock, and hence change the permeability of the rock. Studies demonstrate that grain size significantly affects the mechanical properties and strength of rock, yet little research exists on the effect of grain size on stress-sensitive seepage behavior. In this study, we investigated the effect of grain size on the stress-dependent flow behavior of a porous rock using the three-dimensional discrete element method. We modeled the porous rock geometry using randomly generated rigid spherical grains of given size distribution enclosed in a cuboid. Particle-particle interactions and wall-particle interactions are governed by the Flat-Joint contact model. Rigid boundary walls are used, and a constant strain rate is applied to the boundaries to reach a pre-defined confining stress state. Subsequently, we used the pore scale finite volume method to model the steady-state fluid flow of single-phase fluid at each confining stress state of the model. The permeability-stress relationship data is best described by the exponential model, and the exponent of the exponential model (stress-sensitive coefficient) indicates how rapidly the permeability changes with stress. Our results show that the stress-sensitive coefficient varied very little with the grain size and shows a general decreasing trend with an increase in the mean grain size of the spherical pack. We argue that the effect of other parameters such as pore morphology, micro-cracks, and cementation has a greater influence on the stress-sensitive permeability than the grain size alone. INTRODUCTION The subsurface in-situ stresses exhibit dynamism, which is attributed to the influence of several anthropogenic factors such as reservoir depletion during hydrocarbon extraction, CO2 sequestration, geothermal activities, nuclear waste disposal, and natural causes arising from tectonic movements. Such stress variations significantly impact the physical properties of rocks, particularly their porosity, permeability, and dynamic elastic properties. Given the practical applications associated with these effects, the geoscience community has shown significant interest in this aspect.
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Bagaev, Andrei, Andrei Bagaev, Irina Chubarenko y Irina Chubarenko. "microplastics, numerical modelling, the Baltic Sea, anthropogenic pollution". En Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b93d66c1b80.07366457.
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An overview of modern approaches to the problem of parametrisation of sources of marine waters microplastics pollution from the coastline is conducted. The estimates of Europe’s plastic production along with mismanaged plastic waste percentage that might be the source of microplastics particles input to marine environment are presented. A semi-empirical for-mulation for the particles source intensity is suggested. It considers the main factors of local anthropogenic pressure for the coastal spot location for the given coordinates. Both ad-vantages and disadvantages of such an approach along with possible ways for improvement are discussed.
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Bagaev, Andrei, Andrei Bagaev, Irina Chubarenko y Irina Chubarenko. "microplastics, numerical modelling, the Baltic Sea, anthropogenic pollution". En Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4317340b50.
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An overview of modern approaches to the problem of parametrisation of sources of marine waters microplastics pollution from the coastline is conducted. The estimates of Europe’s plastic production along with mismanaged plastic waste percentage that might be the source of microplastics particles input to marine environment are presented. A semi-empirical for-mulation for the particles source intensity is suggested. It considers the main factors of local anthropogenic pressure for the coastal spot location for the given coordinates. Both ad-vantages and disadvantages of such an approach along with possible ways for improvement are discussed.
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AlShamary, Noora Mahmood AlJathelah, Debapriya Mondal y Hutchinson Simon. "Organic Pollutants along the Qatari Coast: A Case Study of the Pearl Oyster (Pinctada radiata)". En Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0007.
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The Qatari marine environment is endangered due to high industrial expansion and anthropogenic pressure over the last few decades. The presence of common contaminants such as total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) is a threat to the marine environment. The aim of this study is to determine the environmental threats and risks posed by organic contaminants to Qatar’s marine environment using pearl oyster ‘Pinctada Radiata’ as the indicator study organism. The samples (marine sediment, seawater, and oysters) were collected four times within two years in different seasons from the four sites (Simaisma, Al Khor, Umm Bab, and Al Wakra), on March 2017, December 2017, May 2018, and November 2018. A total of 144 samples were analyzed, 48 samples of seawater, 48 samples of sediment and 48 samples of oysters. Levels of organic contaminants (TPHs and PAHs) were quantified in seawater, marine sediment and oyster tissues (P. radiata). In addition, the TOC and particle sizes were measured in abiotic matrices as well as the temperature, salinity, and pH of seawater in the study areas. Overall, the organic contaminants (TPHs and PAHs) were more readily detected in oyster tissue samples than marine sediment and seawater samples collected from the same areas. The surface seawater samples showed negligible levels of PAHs, while TPHs were ranged from 1.164 to 271.77 μg/L. The concentration of TPHs and PAHs in surface marine sediment were ranged between (75.02 -1751.82) and (4.25 - 36.73) μg/kg dry weight respectively. In oyster tissue samples, the level of TPHs was ranged from 633.33 to 6666.67 μg/kg dry weight, with the highest concentrations measured in Simaisma, while PAHs concentration showed an extreme variation from 25.90 to 2244.03μg/kg dry weight. The present study could, however, provide useful background information for further investigations to understand the presence of organic contaminants in Qatar’s marine environment.
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Catianis, Irina, Dan-Lucian Vasiliu, Adriana Maria Constantinescu, Bogdan Ispas y Oana Dobre. "GEOCHEMICAL CHARACTERIZATION OF ORGANIC-RICH LACUSTRINE SEDIMENTS FROM ROSULET, ROSU AND PUIU LAKES, DANUBE DELTA, ROMANIA". En 22nd International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022v/3.2/s12.10.
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Several geochemical analyses (bulk parameters, particle size, loss on ignition, major, minor and trace elements) were performed on 51 recent sediment samples collected in May 2022 from Rosulet, Rosu and Puiu lakes which are located in the fluvio-marine delta plain of the Danube Delta, Romania. The aim of this study was to decipher the potential origin of anthropogenic and/or natural sources, weathering, sedimentary processes and the local geochemical fingerprint on the distribution of specific chemical elements in lacustrine sediments. The resulting compositional dataset showed an interesting spatial variation of the investigated variables. Loss on ignition identified higher concentration of sedimentary organic matter (TOM%) suggesting the autochthonous input derived largely from macro-and micro-phytoplankton, remnants of the biota etc. Similarly, the higher concentrations of total carbonates (CAR%) are attributed to autochthonous input being associated with biogenic debris. Generally, the particle size results exhibited that the lacustrine samples belong to the textural categories as sandy silt and silt. The spatial distribution of major (CaCO3%, TOC%, Fe2O3%), minor (MnO%) and trace components (Rb, Sr, Zr mg/kg) is considerably influenced by the sediment catchment basin lithology. Technophilic elements results (As, Cr, Cu, Hg, Ni, Pb, V and Zn) were related to the maximum allowable limits (MAL) and/or to the natural background reference values stipulated by the national environmental references. Based on the results of contamination analysis, most of the heavy metals (Cr, Cu Pb and Zn) were below the limits (MAL), implying that they have insignificant environmental risk. Instead, the obtained results implied a relatively high concentration of As, Hg, Ni and V, which exceed the corresponding reference standards in some samples. This may be attributed to the presence of allochthonous elevated concentrations of metals transported by the main and secondary hydrographic network waterways up to the interdistributary depressions, or as a consequence of autochthonous input, reflecting a local signature of the natural geochemical fingerprint. The findings from this study provide useful information for the environmental risk assessment relating to the current environmental conditions within deltaic ecosystems as an integral part of the Danube Delta Biosphere Reserve, one of the world�s most important and vulnerable areas in terms of pollution, Danube River water levels, extreme weather conditions (floods and droughts), and other factors exacerbated by the climate change.
Informes sobre el tema "Anthropogenic particle"
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Clausen, Jay, Samuel Beal, Thomas Georgian, Kevin Gardner, Thomas Douglas y Ashley Mossell. Effects of milling on the metals analysis of soil samples containing metallic residues. Engineer Research and Development Center (U.S.), julio de 2021. http://dx.doi.org/10.21079/11681/41241.
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Metallic residues are distributed heterogeneously onto small-arms range soils from projectile fragmentation upon impact with a target or berm backstop. Incremental Sampling Methodology (ISM) can address the spatially heterogeneous contamination of surface soils on small-arms ranges, but representative kilogram-sized ISM subsamples are affected by the range of metallic residue particle sizes in the sample. This study compares the precision and concentrations of metals in a small-arms range soil sample processed by a puck mill, ring and puck mill, ball mill, and mortar and pestle prior to analysis. The ball mill, puck mill, and puck and ring mill produced acceptable relative standard deviations of less than 15% for the anthropogenic metals of interest (Lead (Pb), Antimony (Sb), Copper (Cu), and Zinc (Zn)), with the ball mill exhibiting the greatest precision for Pb, Cu, and Zn. Precision by mortar and pestle, without milling, was considerably higher (40% to >100%) for anthropogenic metals. Media anthropogenic metal concentrations varied by more than 40% between milling methods, with the greatest concentrations produced by the puck mill, followed by the puck and ring mill and then the ball mill. Metal concentrations were also dependent on milling time, with concentrations stabilizing for the puck mill by 300 s but still increasing for the ball mill over 20 h. Differences in metal concentrations were not directly related to the surface area of the milled sample. Overall, the tested milling methods were successful in producing reproducible data for soils containing metallic residues. However, the effects of milling type and time on concentrations require consideration in environmental investigations.
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Jimenez, Jose-Luis, Douglas A. Day, Scot T. Martin, Saewung Kim, James Smith, Rodrigo Souza y Henry Barbosa. Brazil-USA Collaborative Research: Modifications by Anthropogenic Pollution of the Natural Atmospheric Chemistry and Particle Microphysics of the Tropical Rain Forest During the GoAmazon Intensive Operating Periods (IOPs). Office of Scientific and Technical Information (OSTI), agosto de 2017. http://dx.doi.org/10.2172/1374492.
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Kim, Saewung. Brazil-USA Collaborative Research: Modifications by Anthropogenic Pollution of the Natural Atmospheric Chemistry and Particle Microphysics of the Tropical Rain Forest During the GoAmazon Intensive Operating Periods (IOPs). Office of Scientific and Technical Information (OSTI), agosto de 2017. http://dx.doi.org/10.2172/1414578.
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Martin, Scot. Brazil-USA Collaborative Research: Modifications by Anthropogenic Pollution of the Natural Atmospheric Chemistry and Particle Microphysics of the Tropical Rain Forest During the GoAmazon Intensive Operating Periods (IOPs). Office of Scientific and Technical Information (OSTI), febrero de 2018. http://dx.doi.org/10.2172/1419006.
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