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Diversidade bacteriana do gene 16S rRNA em carvão pirogênico de Terra Preta Antropogênica da Amazônia Central e Oriental; Bacterial diversity of the 16S rRNA gene in pyrogenic black carbon of Anthropogenic Dark Earth from the Central and Oriental Amazon

Terceti, Mateus de Souza
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/08/2009 PT
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66.4%
A Terra Preta Antropogênica (TPA) tem essa denominação porque é encontrada em sítios arqueológicos, onde viveram grupos pré-históricos e é considerada um dos solos mais férteis do mundo. Nela é encontrada grande quantidade de material deixado por grupos indígenas como fragmentos cerâmicos, artefatos líticos, e especialmente carvão pirogênico. Estudos realizados com o carvão pirogênico verificaram que ele aumenta a capacidade de trocas catiônicas nesses solos. Por meio de microscopia de fluorencência, foi observada a presença de microrganismos habitando esse carvão, no entanto, não se sabe quais seriam. Devido à falta de informações sobre a diversidade bacteriana nessas estruturas, este trabalho estudou a diversidade bacteriana em amostras de carvão pirogênico de solos TPA coletadas nos sítios Lagoa Balbina (Amazônia Central- Amazonas) e Mina I (Amazônia Oriental - Pará), através de técnicas moleculares independentes de cultivo. O estudo visou também comparar essa diversidade com a encontrada no solo de onde carvão foi isolado. As estruturas de carvão foram separadas fisicamente dos solos e seu DNA genômico total extraído e usado como molde em reação de PCR utilizando oligonucleotídeos do gene 16S rRNA para o Domínio Bacteria. O produto da PCR foi clonado em vetor e os clones foram sequenciados e comparados com o banco de dados de 16S rRNA do RDPX. Com a construção das bibliotecas de clones do gene 16S rRNA a partir das amostras de carvão pirogênico observou-se que existe maior número de bactérias desconhecidas no carvão pirogênico do que no solo onde ele foi isolado. Acidobacteria foi o filo predominante nas bibliotecas de carvão pirogênico das duas localidades de estudo...

Significant enhancements of nitrogen oxides, black carbon, and ozone in the North Atlantic lower free troposphere resulting from North American boreal wildfires

Val Martin, Maria; Honrath, Richard; Owen, R. Chris; Pfister, G.; Fialho, Paulo; Barata, Filipe
Fonte: American Geophysical Union (AGU) Publicador: American Geophysical Union (AGU)
Tipo: Artigo de Revista Científica
Publicado em 07/12/2006 ENG
Relevância na Pesquisa
66.08%
Copyright © 2006 American Geophysical Union. All Rights Reserved.; Extensive wildfires burned in northern North America during summer 2004, releasing large amounts of trace gases and aerosols into the atmosphere. Emissions from these wildfires frequently impacted the PICO-NARE station, a mountaintop site situated 6–15 days downwind from the fires in the Azores Islands. To assess the impacts of the boreal wildfire emissions on the levels of aerosol black carbon (BC), nitrogen oxides and O3 downwind from North America, we analyzed measurements of CO, BC, total reactive nitrogen oxides (NO y ), NO x (NO + NO2) and O3 made from June to September 2004 in combination with MOZART chemical transport model simulations. Long-range transport of boreal wildfire emissions resulted in large enhancements of CO, BC, NO y and NO x , with levels up to 250 ppbv, 665 ng mˉ³, 1100 pptv and 135 pptv, respectively. Enhancement ratios relative to CO were variable in the plumes sampled, most likely because of variations in wildfire emissions and removal processes during transport. Analyses of ΔBC/ΔCO, ΔNO y /ΔCO and ΔNO x /ΔCO ratios indicate that NO y and BC were on average efficiently exported in these plumes and suggest that decomposition of PAN to NO x was a significant source of NO x . High levels of NO x suggest continuing formation of O3 in these well-aged plumes. O3 levels were also significantly enhanced in the plumes...

Ten Years of Black Carbon Measurements in the North Atlantic at the Pico Mountain Observatory, Azores (2225m asl).

Kumar, Sumit; Fialho, Paulo; Mazzoleni, Lynn R.; Olsen, Seth C.; Owen, R. Chris; Helmig, Detlev; Hueber, Jacques; Dziobak, Michael P.; Kramer, Louisa; Mazzoleni, Claudio
Fonte: Universidade dos Açores Publicador: Universidade dos Açores
Tipo: Conferência ou Objeto de Conferência
Publicado em /12/2012 ENG
Relevância na Pesquisa
66.08%
45th annual Fall Meeting, AGU. San Francisco, California, 3-7 December.; The Pico Mountain Observatory is located in the summit caldera of the Pico mountain, an inactive volcano on the Pico Island in the Azores, Portugal (38.47°N, 28.40°W, Altitude 2225m asl). The Azores are often impacted by polluted outflows from the North American continent and local sources have been shown to have a negligible influence at the observatory. The value of the station stems from the fact that this is the only permanent mountaintop monitoring station in the North Atlantic that is typically located above the marine boundary layer (average MBL heights are below 1200 m and rarely exceed 1300 m) and often receives air characteristic of the lower free troposphere. Measurements of black carbon (BC) mass have been carried out at the station since 2001, mostly in the summer seasons. Here we discuss the BC decadal dataset (2001-2011) collected at the site by using a seven-wavelength AE31 Magee Aethalometer. Measured BC mass and computed Angstrom exponent (AE) values were analysed to study seasonal and diurnal variations. There was a large day-to-day variability in the BC values due to varied meteorological conditions that resulted in different diurnal patterns for different months. The daily mean BC at this location ranged between 0 and ~430 ngm-3...

Identification of black carbon and dust aerosol events at the Azores PICO-NARE station during the ICARTT experiment.

Fialho, Paulo; Barata, Filipe; Honrath, Richard; Hansen, Anthony
Fonte: Universidade dos Açores Publicador: Universidade dos Açores
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2005 ENG
Relevância na Pesquisa
66.12%
European Geosciences Union (EGU), General Assembly. Viena, Austria, 24-29 April 2005.; During the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) experiment (July – August 2004), aerosol samples were taken and their aerosol absorption coefficients measured. At the same time the levels of carbon monoxide and ozone where also monitored. These measurements were taken at PICO-NARE site on Pico mountain summit (2225 m ASL) in the Azores Islands. This site is in the pathway of air masses that travel from the surrounding continents (Africa, Europe and North America) that carry with them, among other species, aerosols resulting from combustions (black carbon) and/or natural emissions (dust). In particular, transport from Africa may bring soil dust particles, rich in iron oxides, which are involved in the biogeochemical cycling of iron, an essential micronutrient to marine phytoplankton (Arimoto, Balsam, & Schloesslin, 2002). During this period the sampled masses mainly came form the North American and during sometimes carried with them pollutants resulting from forest fires that occurred in Canada and Alaska.

Black carbon contents and distribution in sediments from the southeastern Brazilian coast (Guanabara Bay)

Ribeiro,Letícia G. L.; Carreira,Renato S.; Wagener,Angela L. R.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
66.18%
The concentration of black carbon (BC), as well as the relative contribution of BC to total organic carbon, was determined for the first time in sediments from Guanabara Bay. BC was quantified by a thermal oxidation method (CTO-375) and total organic carbon by dry oxidation. Sedimentary organic carbon showed a large range in concentrations (0.82 to 10.3%), but it was possible to define distinct regions of the Bay accordingly to variations in sediment grain size, location and magnitude of allochthonous and autochthonous sources of organic matter and hydrodynamic features. Low concentrations of BC were observed (0.03 to 0.31%, with a mean of 0.19 ± 0.07%, n = 25) when considering the large spectrum of possible sources on land and at sea. However, in some stations levels are sufficiently high as to influence the fate of pollutants of concern, such as PAH and dioxins. The space distribution of BC concentrations in Guanabara Bay cannot be fully understood at this stage since further information on contributions from various sources and on natural dispersion processes are required.

High-time resolution measurements of black carbon particles in the exhaust emissions of a diesel engine during acceleration, deceleration and cruise conditions

Miguel,Antonio H.; Hansen,Anthony D. A.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
66.15%
Black carbon (BC) is a major constituent of diesel-engine exhaust emissions. Aethalometer® was used in the measurements of the BC concentrations (with time resolution of 5 s) in the exhaust of a truck model 1995 Dodge RAM 2500 diesel pick-up equipped with an oxidation catalyst. The measurements were made from a chassis dynamometer during the acceleration, deceleration and cruise (constant speed) modes of the hot start of the MEC01 test cycle (version 7.0). Exhaust particles were collected in parallel on quartz fiber filters for elemental carbon (EC) and organic carbon (OC) measurement by the thermal-optical reflectance (TOR) method, and on Teflon® filters for gravimetric total particle mass (PM). Rapid acceleration was accompanied by corresponding instantaneous increases in BC emissions. Under wide open throttle acceleration (WOT), Aethalometer® BC concentrations peaked at 1.2 mg m-3, but reduced to only 0.03 mg m-3 under cruise conditions at 20 mph. These results show that it is possible to measure speciated diesel particulate emissions essentially in real time as a function of engine load and other operating conditions.

Black Carbon Exposures, Blood Pressure, and Interactions with Single Nucleotide Polymorphisms in MicroRNA Processing Genes

Wilker, Elissa Hope; Baccarelli, Andrea; Suh MacIntosh, Helen H.; Vokonas, Pantel S; Wright, Robert O.; Schwartz, Joel David
Fonte: National Institute of Environmental Health Sciences Publicador: National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.08%
Background: Black carbon (BC) is a marker of traffic pollution that has been associated with blood pressure (BP), but findings have been inconsistent. MicroRNAs (miRNAs) are emerging as key regulators of gene expression, but whether polymorphisms in genes involved in processing of miRNAs to maturity influence susceptibility to BC has not been elucidated. Objectives: We investigated the association between BC and BP, as well as potential effect modification by single nucleotide polymorphisms (SNPs) in miRNA processing genes. Methods: Repeated measures analyses were performed using data from the VA Normative Aging Study. Complete covariate data were available for 789 participants with one to six study visits between 1995 and 2008. In models of systolic and diastolic BP, we examined SNP-by-BC interactions with 19 miRNA-related variants under recessive models of inheritance. Mixed-effects models were adjusted for potential confounders including clinical characteristics, lifestyle, and meteorologic factors. Results: A 1-SD increase in BC (0.415 μg/m3) was associated with 3.04 mmHg higher systolic (95% confidence interval (CI), 2.29–3.79) and 2.28 mmHg higher diastolic BP (95% CI, 1.88–2.67). Interactions modifying BC associations were observed with SNPs in the DICER...

Black Carbon Exposure, Oxidative Stress Genes, and Blood Pressure in a Repeated-measures Study

Mordukhovich, Irina; Wilker, Elissa Hope; Suh MacIntosh, Helen H.; Wright, Robert O.; Sparrow, David; Vokonas, Pantel S; Schwartz, Joel David
Fonte: National Institute of Environmental Health Sciences Publicador: National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.08%
Background: Particulate matter (PM) air pollution has been associated with cardiovascular morbidity and mortality, and elevated blood pressure (BP) is a known risk factor for cardiovascular disease. A small number of studies have investigated the relationship between PM and BP and found mixed results. Evidence suggests that traffic-related air pollution contributes significantly to PM-related cardiovascular effects. Objectives: We hypothesized that black carbon (BC), a traffic-related combustion by-product, would be more strongly associated with BP than would fine PM [aerodynamic diameter ≤ 2.5 μm (PM(_{2.5}))], a heterogeneous PM mixture, and that these effects would be larger among participants with genetic variants associated with impaired antioxidative defense. Methods: We performed a repeated-measures analysis in elderly men to analyze associations between PM(_{2.5}) and BC exposure and BP using mixed-effects models with random intercepts, adjusting for potential confounders. We also examined statistical interaction between BC and genetic variants related to oxidative stress defense: GSTM1, GSTP1, GSTT1, NQO1, catalase, and HMOX-1. Results: A 1-SD increase in BC concentration was associated with a 1.5-mmHg increase in systolic BP [95% confidence interval (CI)...

Residential Black Carbon Exposure and Circulating Markers of Systemic Inflammation in Elderly Males: The Normative Aging Study

Alexeeff, Stacey E.; Gryparis, Alexandros; Fang, Shona C.; Mehta, Amar Jayant; Coull, Brent Andrew; Vokonas, Pantel S.; Christiani, David C.; Schwartz, Joel David
Fonte: National Institute of Environmental Health Sciences Publicador: National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.08%
Background: Traffic-related particles (TRPs) are associated with adverse cardiovascular events. The exact mechanisms are unclear, but systemic inflammatory responses likely play a role. Objectives: We conducted a repeated measures study among male participants of the Normative Aging Study in the greater Boston, Massachusetts, area to determine whether individual-level residential black carbon (BC), a marker of TRPs, is associated with systemic inflammation and whether coronary heart disease (CHD), diabetes, and obesity modify associations. Methods: We quantified markers of inflammation in 1,163 serum samples from 580 men. Exposure to BC up to 4 weeks prior was predicted from a validated spatiotemporal land-use regression model. Linear mixed effects models estimated the effects of BC on each marker while adjusting for potential confounders. Results: Associations between BC and blood markers were not observed in main effects models or when stratified by obesity status. However, BC was positively associated with markers of inflammation in men with CHD (particularly vascular endothelial growth factor) and in men with diabetes (particularly interleukin-1(eta) and tumor necrosis factor-(alpha)). Significant exposure time windows varied by marker...

Global budget of black carbon aerosol and implications for climate forcing

Wang, Qiaoqiao
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
66.08%
This thesis explores the factors controlling the distribution of black carbon (BC) in the atmosphere/troposphere and its implications for climate forcing. BC is of great climate interest because of its warming potential. Estimates of BC climate forcing have large uncertainty, in part due to poor knowledge of the distribution of BC in the atmosphere. This dissertation first examines the factors controlling the sources of BC in the Arctic in winter and spring using a global chemical transport model (GEOS-Chem). Emission inventories of BC and wet scavenging of aerosols in the model are updated to reproduce observed atmospheric concentrations of BC as well as observed snow BC content in the Arctic in winter-spring. The simulation shows a dominant contribution of fuel (fossil fuel and biofuel) combustion to BC in Arctic spring. Arctic snow BC content is dominated by fuel combustion sources in winter, but has equal contributions from open fires and fuel combustion in spring. The estimated decrease in Arctic snow albedo due to BC deposition in spring is 0.6%, resulting in a regional surface radiative forcing of 1.2 W m-2. The dissertation then extends the evaluation of the BC simulation to the global scale using aircraft observations over source regions...

Mitochondrial haplogroups modify the effect of black carbon on age-related cognitive impairment

Colicino, Elena; Power, Melinda C; Cox, David G; Weisskopf, Marc G; Hou, Lifang; Alexeeff, Stacy E; Sanchez-Guerra, Marco; Vokonas, Pantel; Spiro III, Avron; Schwartz, Joel; Baccarelli, Andrea A
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.08%
Background: Traffic-related air pollution has been linked with impaired cognition in older adults, possibly due to effects of oxidative stress on the brain. Mitochondria are the main source of cellular oxidation. Haplogroups in mitochondrial DNA (mtDNA) mark individual differences in oxidative potential and are possible determinants of neurodegeneration. The aim of this study was to investigate whether mtDNA haplogroups determined differential susceptibility to cognitive effects of long-term exposure to black carbon (BC), a marker of traffic-related air pollution. Methods: We investigated 582 older men (72 ± 7 years) in the VA Normative Aging Study cohort with ≤4 visits per participant (1.8 in average) between 1995–2007. Low (≤25) Mini Mental State Examination (MMSE) was used to assess impaired cognition in multiple domains. We fitted repeated-measure logistic regression using validated-LUR BC estimated in the year before their first visit at the participant’s address. Results: Mitochondrial haplotyping identified nine haplogroups phylogenetically categorized in four clusters. BC showed larger effect on MMSE in Cluster 4 carriers, including I, W and X haplogroups, [OR = 2.7; 95% CI (1.3-5.6)], moderate effect in Cluster 1...

Black Carbon and Climate Change : Considerations for International Development Agencies

Levitsky, Michael
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
Relevância na Pesquisa
66.34%
This report is intended to inform the international development community about the links between black (BC) carbon and climate change. With growing scientific clarity on the contribution of black carbon to climate change, the benefits of limiting its emissions are becoming more evident. This report reviews the existing knowledge on the subject and identifies relevant considerations for development organizations. Climate modeling shows that a large reduction in the global amounts of BC emissions, without changes in emissions of organic carbon, will lead to a sharp onetime decrease in the warming influence of human activities. A rapid reduction in BC emissions has thus been proposed as a way to partially offset the projected increase in temperatures in coming decades. This will not solve the long-term problem of climate change, which is caused by the greenhouse gas (GHGs), but it could extend the limited time that is available to reduce emissions of GHGs aggressively, before global temperatures reach dangerous levels. Proposals to reduce BC emissions also often address the need to reduce emissions of several other short-lived gases (such as ozone) that are mostly not covered by the Kyoto Protocol. This paper is designed to inform development agencies...

Environmental Dynamics of Dissolved Black Carbon in Aquatic Ecosystems

Ding, Yan
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
66.27%
Black carbon (BC), the incomplete combustion product from biomass and fossil fuel burning, is ubiquitously found in soils, sediments, ice, water and atmosphere. Because of its polyaromatic molecular characteristic, BC is believed to contribute significantly to the global carbon budget as a slow-cycling, refractory carbon pool. However, the mass balance between global BC generation and accumulation does not match, suggesting a removal mechanism of BC to the active carbon pool, most probable in a dissolved form. The presence of BC in waters as part of the dissolved organic matter (DOM) pool was recently confirmed via ultrahigh resolution mass spectrometry, and dissolved black carbon (DBC), a degradation product of charcoal, was found in marine and coastal environments. However, information on the loadings of DBC in freshwater environments and its global riverine flux from terrestrial systems to the oceans remained unclear. The main objectives of this study were to quantify DBC in diverse aquatic ecosystems and to determine its environmental dynamics. Surface water samples were collected from aquatic environments with a spatially significant global distribution, and DBC concentrations were determined by a chemical oxidation method coupled with HPLC detection. While it was clear that biomass burning was the main sources of BC...

Environmental Dynamics of Dissolved Black Carbon in Wetlands

Ding, Yan; Cawley, Kaelin M.; Nunes da Cunha, Catia; Jaffe´, Rudolf
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.17%
Wetlands are ecosystems commonly characterized by elevated levels of dissolved organic carbon (DOC), and although they cover a surface area less than 2 % worldwide, they are an important carbon source representing an estimated 15 % of global annual DOC flux to the oceans. Because of their unique hydrological characteristics, fire can be an important ecological driver in pulsed wetland systems. Consequently, wetlands may be important sources not only of DOC but also of products derived from biomass burning, such as dissolved black carbon (DBC). However, the biogeochemistry of DBC in wetlands has not been studied in detail. The objective of this study is to determine the environmental dynamics of DBC in different fire-impacted wetlands. An intensive, 2-year spatial and temporal dynamics study of DBC in a coastal wetland, the Everglades (Florida) system, as well as one-time sampling surveys for the other two inland wetlands, Okavango Delta (Botswana) and the Pantanal (Brazil), were reported. Our data reveal that DBC dynamics are strongly coupled with the DOC dynamics regardless of location, season or recent fire history. The statistically significant linear regression between DOC and DBC was applied to estimate DBC fluxes to the coastal zone through two main riverine DOC export routes in the Everglades ecosystem. The presence of significant amounts of DBC in these three fire-impacted ecosystems suggests that sub-tropical wetlands could represent an important continental-ocean carrier of combustion products from biomass burning. The discrimination of DBC molecular structure (i.e. aromaticity) between coastal and terrestrial samples...

Dissolved Black Carbon in Grassland Streams: Is There an Effect of Recent Fire History?

Ding, Yan; Yamashita, Youhei; Dodds, Walter K.; Jaffe´, Rudolf
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.22%
While the existence of black carbon as part of dissolved organic matter (DOM) has been confirmed, quantitative determinations of dissolved black carbon (DBC) in freshwater ecosystem and information on factors controlling its concentration are scarce. In this study, stream surface water samples from a series of watersheds subject to different burn frequencies in Konza Prairie (Kansas, USA) were collected in order to determine if recent fire history has a noticeable effect on DBC concentration. The DBC levels detected ranged from 0.04 to 0.11 mg L−1, accounting for ca. 3.32 ± 0.51% of dissolved organic carbon (DOC). No correlation was found between DBC concentration and neither fire frequency nor time since last burn. We suggest that limited DBC flux is related to high burning efficiency, possibly greater export during periods of high discharge and/or the continuous export of DBC over long time scales. A linear correlation between DOC and DBC concentrations was observed, suggesting the export mechanisms determining DOC and DBC concentrations are likely coupled. The potential influence of fire history was less than the influence of other factors controlling the DOC and DBC dynamics in this ecosystem. Assuming similar conditions and processes apply in grasslands elsewhere...

Aromatic condensation of black carbon : its measurement and importance.

McBeath, Anna Vera
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012
Relevância na Pesquisa
66.12%
Black carbon (BC) is an important constituent of soils and sediments due to its role in a range of biogeochemical processes. However, since BC represents a continuum of materials with no clear-cut boundaries, it is challenging to identify and quantify. This limits our understanding of its contribution to terrestrial, marine and atmospheric carbon cycles and the role it plays in influencing climate. The focus of this study was on first improving and refining a novel solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopic that offers great potential for the characterisation of BC. Once optimised, this technique was applied to a variety of BC samples in order to address some key questions in BC science. The technique developed here is a simple and rapid method for gauging the degree of aromatic condensation of chars, a molecular-scale property that affects both their degradability and sorption affinity. The foundation for the technique has been described previously. Its basis is the effect that “ring currents” that are induced in aromatic structures have on the ¹³C NMR chemical shift of probe molecules when sorbed to the char. The improvement in the technique described here involves a direct addition of the probe molecule (¹³C₆-benzene) directly to the dry char. This is demonstrated to be a much more efficient method of loading the probe molecule...

Black Carbon: Sources, Mobility and Fate in Freshwater Systems

Wagner, Sasha
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
66.31%
Black carbon (BC) is a complex mixture of polycondensed aromatic compounds produced by the incomplete combustion of biomass during events such as wildfires and the burning of fossil fuels. Black carbon was initially considered to be a refractory form of organic matter. However, recent studies have shown that BC can be quite mobile and reactive in the terrestrial environment. Black carbon can be translocated from soils and sediments in the form of dissolved BC (DBC). A global correlation between DBC and bulk dissolved organic carbon (DOC) has been established for fluvial systems where DBC comprises approximately 10% of the total DOC pool, which suggests that DBC may be a significant contributor to the global carbon cycle. The primary objective of this thesis was to further characterize DBC and elucidate some of the specific physical and chemical processes that promote its transfer to the aqueous phase and drive the DBC-DOC relationship. The molecular composition and qualitative distribution of DBC was assessed using Fourier transform ion cyclotron resonance mass spectrometry. Black carbon in both dissolved and particulate (PBC) phases was quantified by the benzenepolycarboxylic acid method. Dissolved BC was found to contain considerable amounts of nitrogen and the export of this dissolved black nitrogen was linked to watershed land use in global rivers. The riverine flux of PBC...

Reducing Black Carbon Emissions from Diesel Vehicles : Impacts, Control Strategies, and Cost-Benefit Analysis

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
66.4%
A 2013 scientific assessment of black carbon emissions and impacts found that black carbon is second to carbon dioxide in terms of its climate forcing. High concentrations of black carbon in the atmosphere can change precipitation patterns and reduce the amount of radiation that reaches the Earth's surface, which affects local agriculture. Acute and chronic exposures to particulate matter are associated with a range of diseases, including chronic bronchitis and asthma, as well as premature deaths from cardiopulmonary disease, lung cancer, and acute lower respiratory infections. The transportation sector accounted for approximately 19 percent of global black carbon emissions in the year 2000. This report aims to inform efforts to control black carbon emissions from diesel-based transportation in developing countries. It presents a summary of emissions control approaches from developed countries, while recognizing that developing countries face a number of on-the-ground implementation challenges. This study applies a new cost-benefit analysis methodology to four simulated diesel black carbon emissions control projects - diesel retrofit in Istanbul...

Reconstructing historical changes in combustion patterns by means of black carbon and pah evaluation in dated sediments from Guanabara Bay, Rio de Janeiro

Mauad,Cristiane R.; Wagener,Angela de L. R.; Farias,Cássia de O.; Ruiz,Naira M. S.; Carreira,Renato S.; Vasconcelos,Crisógono; Godoy,José M.; Menezes,Sonia M. C. de; Scofield,Arthur de L.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2013 EN
Relevância na Pesquisa
66.12%
The accumulation history of combustion products from the metropolitan area around Guanabara Bay was evaluated using black carbon and polycyclic aromatic hydrocarbons as indicators. BC concentration varied between 0.23 and 0.51%, with an increasing mass accumulation tendency over the last 118 years, whereas a decrease in the values of the ratio BC/organic carbon was observed in the upper sediment layers, probably reflecting the enhancement of bay's eutrophication process in the last 30 years. Higher concentrations of pyrolytic PAH were observed between 1925 and 1976, being consistent with the subsequent deforestation, urbanization, and industrialization that occurred in the Guanabara basin in the period. These PAHs were best characterized by the BFl/(BFl+BePy) diagnostic ratio. The data obtained allowed the characterization of the main events that influenced the combustion patterns in the region: burning of biomass and fossil fuel, economic crisis of 1970 and 1990 and the introduction of ethanol in the Brazilian energetic matrix.

Black carbon and organic carbon emissions from wildfires in Mexico

CRUZ NÚÑEZ,XÓCHITL; VILLERS RUIZ,LOURDES; GAY GARCÍA,CARLOS
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 EN
Relevância na Pesquisa
66.35%
In Mexico, approximately 7650 wildfires occur annually, affecting 263 115 hectares of land. In addition to their impact on land degradation, wildfires cause deforestation, damage to ecosystems and promote land use change; apart from being the source of emissions of toxic substances to the environment (i.e., hydrogen cyanide, black carbon and organic carbon). Black carbon is a short-lived greenhouse pollutant that also promotes snow and ice melting and decreased rainfall; it has an estimated global warming potential close to 5000.¹ We present an estimate of the black carbon and organic carbon emissions from wildfires in Mexico from 2000 to 2012 using selected emission factors from the literature and activity data from local agencies. The results show average emissions of 5955 Mg/yr for black carbon and 62 085 Mg/yr for organic carbon. Black carbon emissions are estimated to be 14 888 Gg CO2 equivalent (CO2 eq) per year on average. With proper management of wildfires, such emissions can be mitigated. Moreover, improved air quality, conservation of ecosystems, improvement of visibility and maintenance of land use are a subset of the related co-benefits. Mitigating forest organic carbon emissions, which are ten times higher than black carbon emissions...