RESUMO
Mercury (Hg) emissions from forest fires, especially tropical forests such as the Amazonian forest, were shown to contribute significantly to the atmospheric mercury budget, but new methods are still necessary to improve the traceability and to reduce the great uncertainties related to this emission source. Recent studies have shown that the combustion process can result in Hg stable isotope fractionation that allows tracking coal combustion Hg emissions, as influenced by different factors such as combustion temperature. The main goal of the present study was, therefore, to investigate for the first time the potential of Hg stable isotopes to trace forest fire Hg emissions and pathways. More specifically, small-scale and a large scale prescribed forest fire experiments were conducted in the Brazilian Amazonian forest to study the impact of fire severity on Hg isotopic composition of litter, soil, and ash samples and associated Hg isotope fractionation pathways. In the small-scale experiment, no difference was found in the mercury isotopic composition of the samples collected before and after burning. In contrast, the larger-scale experiment resulted in significant mass dependent fractionation (MDF δ202Hg) in soils and ash suggesting that higher combustion temperature influence Hg isotopic fractionation with the emission of lighter Hg isotopes to the atmosphere and enrichment with heavier Hg in ashes. As for coal combustion, mass independent fractionation was not observed. To our knowledge, these results are the first to highlight the potential of forest fires to cause Hg isotopic fractionation, depending on the fire severity. The results also allowed to establish an isotopic fingerprint for tropical forest fire Hg emissions that corresponds to a mixture of litter and soil Hg isotopic composition (resulting atmospheric δ202Hg, Δ200Hg and Δ199Hg were -1.79 ± 0.24, -0.05 ± 0.04 and -0.45 ± 0.12, respectively).
Assuntos
Mercúrio , Incêndios Florestais , Isótopos de Mercúrio/análise , Mercúrio/análise , Solo , Isótopos , Carvão Mineral/análise , Monitoramento AmbientalRESUMO
The impact of aviation on climate change is reflected in increasing emissions of CO2 and other pollutants from fuel burning emitted at high altitudes, representing 2.9 % of total Greenhouse gases (GHG) emissions in 2019. However, mitigations options for decarbonization of aviation are difficult to implement given operational safety, technology maturity, energy density and other constraints. One alternative for mitigation is the use of certified sustainable aviation fuel (SAF) with lower carbon intensity than conventional jet fuel (CJF). This research presents an inventory of Argentine civil aviation emissions for its domestic and international flights, and analyzes the possibility of supplying SAF as a mitigation strategy given its abundant biomass production. Argentine aviation activity is presented as a monthly 4D (latitude, longitude, altitude and time) spatial inventory for the interval 2001-2021, based on origin and destination city pairs, aircraft types and airlines. Fuel consumption and pollutant emissions were calculated for landing-and-take-off and cruise phases. Monthly domestic ranged from 67 to 179 kt CO2eq (2001-2019). Annual peak values occurred in 2019 consuming 560 kt CJF and direct emitting of 1.77 Mt CO2eq. While Revenue-Passenger-Kilometer (RPK) grew almost 4 times (4.18 × 109 in 2001 to 16.42 × 109 in 2019), the number of flights changed only 1.5 times (from 98,000 in 2002 to 152,000 in 2019). The main efficiency indexes varied from 97 t CJF/RPK, 308 gCO2eq/RPK to 34 t CJF/RPK, 107 gCO2eq/RPK between 2001 and 2019, respectively, showing an average annual improvement of 3.5 % due to partial fleet renewal, especially from 2015 onwards. Emissions of other pollutants for 2019 reached total values of CO 14.14 kt; NOx 6.77 kt; PM tot 55.12 kt. For the period 2001-2019, international aviation consumed between 1 Mt - 1.5 Mt CJF, directly emitting between 3.30 and 4.80 Mt of CO2eq; RPKs went from 6.234 × 109 to 20.524 × 109; the efficiency indices ranged from 529 to 240 gCO2eq/RPK. The most important changes occurred with an optimization of routes and number of flights and the replacement of the four-engines (B747, A380) by more efficient twin-engines (B777, A330) aircraft. Argentina is not required to any offsetting regulatory program due to its small aviation market (approx. 0.22 % global market in 2019), nor has to date certified SAF production pathways, nevertheless it has potential for SAF availability based on actual biofuels production (ethanol, biodiesel and soybean oil) and biomass feedstock's existences. In this sense this studies proposes that 2019 domestic fuel consumption could be supplied using 79 % exportable amounts of sugarcane ethanol (257 ± 53 kt) (by Ethanol to Jet ETJ) and 34 % of exportable soybean oil (1079 ± 160 kt) (by hydroprocessed esters and fatty acids- HEFA) pathways. For this scenario average GHG emissions reached 1.321 ± 0.115 Mt CO2eq; which would imply a 62 % of the current emission value using CJF (2.17Mt CO2eq), or savings of about 838 kt CO2eq (38 %). At the 2019 level of harvest and biofuel production, up to 1.4 Mt of SAF could be produced from sugarcane ethanol/ETJ and soybean oil/HEFA mitigating up to 1.8 MtCO2eq. A 35 kt CO2eq annual sectoral national mitigation strategy could be reached by using 14 kt of SAF.
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RESUMO A incineração é uma tecnologia de tratamento térmico de resíduos sólidos cujo principal objetivo é a redução do volume e da massa dos resíduos a serem depositados em aterros. Os incineradores construídos nas últimas décadas trazem a possibilidade de recuperação energética dos resíduos, na forma de vapor e/ou energia elétrica, entretanto essa tecnologia ainda gera questionamentos sobre possíveis impactos ambientais relacionados às suas emissões. A incineração é regulada na Europa por legislação específica que, entre outras questões, obriga a divulgação de dados de monitoramento ambiental de incineradores. No presente trabalho, são analisados dados de emissões atmosféricas de incineradores associados à Confederation of European Waste-to-Energy Plants (CEWEP), por meio de buscas nos websites dos respectivos incineradores, em artigos científicos e relatórios técnicos. Foram examinados dados de monitoramento de todos os poluentes de medição contínua e periódica definidos na legislação da UE, em séries temporais de 2010 a 2017. Todos os valores médios anuais de emissões nos incineradores analisados estiveram abaixo dos limites definidos pela diretiva europeia, com pequena variação ao longo dos anos observados. A comparação dos padrões de emissão europeus com os brasileiros mostra a necessidade de mudança na legislação local referente à incineração para que, caso essa tecnologia seja implementada no Brasil, ela possa operar respeitando limites seguros, com garantia de minimização de impactos ao ambiente e às populações do entorno.
Abstract Incineration is a solid waste treatment technology whose main purpose is to reduce the volume and mass of the waste to be disposed of in landfills. The incinerators built in the last decades bring the possibility of energy recovery from waste, in the form of steam and/or electric energy. However, this technology still raises questions about possible environmental impacts related to its emissions. Incineration is regulated in Europe through specific legislation which, among other issues, requires the disclosure of environmental monitoring data for incinerators. In the present work, atmospheric emissions data from incinerators associated with the Confederation of European Waste-to-Energy Plants (CEWEP) are analyzed by searching the websites of the respective incinerators, scientific articles and technical reports. Monitoring data on all continuous and periodic measured pollutants defined in the legislation in time series from 2010 to 2017 were analyzed. All annual average emission values of the incinerators analyzed were below the limits defined by the European Union's Directive, with little variation over the observed years. The comparison of European with Brazilian emission standards shows the need for a change in local legislation on incineration so that, if this technology is implemented in Brazil, it will operate within safe limits, with a guarantee of minimizing impacts on the environment and surrounding populations.
RESUMO
The atmospheric Pb emissions (1901-2019), from one of the world's largest non-ferrous metallurgical complexes (Met-Mex in Torreón, México), were estimated based on historical records of modifications in the design, processes, and production volumes. Eight historical periods, with differing amounts of Pb emissions, were distinguished: (1) Essentially no controls (1901-1960); (2) migration to limited controls (1961-1972) by conversion to a Pb-Zn smelter-refining complex and installation of SO2 collectors in 1961-1963; (3) completion to limited control (1973-1977) by the installation of a third H2SO4 collector and a low-efficiency filtration system; (4) maintenance of limited control with no changes (1978-1987); (5) migration to strict control (1988 to 1998) by updating H2SO4 collectors and installation of fertilizer and SO2 liquid extraction plants; (6) completion to strict control (1999-2000) by the installation of state-art technology filtration systems and roofing working areas; (7) migration to abatement (2001-2003) by implantation of good management practices; and (8) maintenance of abatement following good management practices (2004-2019). Based on differences between those periods, we reconstructed the evolution of the Pb emission reduction efficiency (ER in %) and Pb emission factors (EF in gram/ton) for the Torreón complex. Pb emitted by the complex over the past 118 years totaled 23,350-27,580 t, with most of it (63-75%) occurring when emission controls were negligible (pre-1960 period). In comparisons with other facilities worldwide (e.g., the USA, Canada, and Europa), the modification in Met-Mex for control the Pb emission occurred several years. Emissions from the primary Pb-Zn smelter-refining are released mostly to the atmosphere from the sintering, smelting, drossing, and refining. While Pb emissions from the facility have declined by over an order of magnitude to contemporary levels (≤ 12.6 t/year), the current Pb rates still account for atmospheric Pb levels that are 2-3 times higher the USEPA standard and still constitutes a major health threat in Torreón.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Canadá , Monitoramento Ambiental , Chumbo , Metalurgia , MéxicoRESUMO
Brazil, one of the world's fastest-growing economies, is the fifth most populous country and is experiencing accelerated urbanization. This combination of factors causes an increase in urban population that is exposed to poor air quality, leading to public health burdens. In this work, the Weather Research and Forecasting Model with Chemistry is applied to simulate air quality over Brazil for a short time period under three future emission scenarios, including current legislation (CLE), mitigation scenario (MIT), and maximum feasible reduction (MFR) under the Representative Concentration Pathway 4.5 (RCP4.5), which is a climate change scenario under which radiative forcing of greenhouse gases (GHGs) reach 4.5 W m-2 by 2100. The main objective of this study is to determine the sensitivity of the concentrations of ozone (O3) and particulate matter with aerodynamic diameter 2.5 µm or less (PM2.5) to changes in emissions under these emission scenarios and to determine the signal and spatial patterns of these changes for Brazil. The model is evaluated with observations and shows reasonably good agreement. The MFR scenario leads to a reduction of 3% and 75% for O3 and PM2.5 respectively, considering the average of grid cells within Brazil, whereas the CLE scenario leads to an increase of 1% and 11% for O3 and PM2.5 respectively, concentrated near urban centers. These results indicate that of the three emission control scenarios, the CLE leads to poor air quality, while the MFR scenario leads to the maximum improvement in air quality. To the best of our knowledge, this work is the first to investigate the responses of air quality to changes in emissions under these emission scenarios for Brazil. The results shed light on the linkage between changes of emissions and air quality.
RESUMO
O pneu inservível é um resíduo que deve ser gerido corretamente até sua disposição final, pois quando disposto inadequadamente pode causar danos ao meio ambiente e à saúde pública. Em João Pessoa, Paraíba, foi iniciado em março de 2005 o Programa Nordeste Rodando Limpo, que consistiu na coleta e destinação final dos pneus inservíveis para utilização como combustível em fornos de fabricação de clínquer. Esta pesquisa foi desenvolvida em uma cimenteira, localizada na cidade de João Pessoa, cujo objetivo foi analisar os principais benefícios da utilização de pneus inservíveis no coprocessamento. A metodologia utilizada foi baseada na avaliação qualitativa dos benefícios gerados à saúde pública e avaliação quantitativa dos ganhos sociais gerados aos catadores, assim como mensurar as emissões atmosféricas do coprocessamento. Os resultados obtidos confirmaram os benefícios no coprocessamento, possibilitando a retirada de 26.569 toneladas de pneus inservíveis que estavam depositados nos estados da Paraíba, Pernambuco e Rio Grande do Norte, além da criação de um mecanismo de coleta pela sociedade, que possibilitou ganhos econômicos da ordem de R$ 2 milhões aos catadores, contribuindo para a melhoria de sua qualidade de vida. Verificou-se também um gradativo aumento da utilização de pneus inservíveis, implicando em um menor consumo de combustíveis não renováveis, minimizando emissões atmosféricas, devido ao menor volume de coque utilizado e transportado.
The wasted tire is a residue that must be properly managed until its final disposal, because when improperly disposed, it can cause damage to the environment and risk to public health. In the city of João Pessoa, Paraíba, Brazil, a program called Programa Nordeste Rodando Limpo was started in March 2005 and consisted of the collecting and disposal of scrap tires to be used as fuel in furnaces for manufacturing of clinker. This research was conducted in a cement factory located in the city of João Pessoa. The main objective was to analyze the benefits of using scrap tires in co-processing. The methodology used was based on qualitative assessment of the benefits generated to the public health; quantitative assessment of the social gains generated to collectors; as well as the measurement of atmospheric emissions during the co-processing. The results confirmed the benefits in co-processing, allowing the removal of 26.569 tons of waste tires that were deposited in the states of Paraiba, Pernambuco and Rio Grande do Norte. A social mechanism for collecting waste tires was created, which enabled economic gains of R$ 2 million to collectors, helping to improve their quality of life. There was also a gradual increase in the use of wasted tires, resulting in a lower consumption of non-renewable fuels, minimizing atmospheric emissions due to the lower volume of petroleum coke used and transported.
RESUMO
MERCURY CONTAMINATION IN BRAZIL: INDUSTRIAL SOURCES vs GOLD MINING. This paper reviews the history of Hg contamination in Brazil by characterizing and quantifying two major sources of Hg emissions to the environment: industrial sources and gold mining. Industry was responsible for nearly 100% of total Hg emissions from the late 1940's to the early 1970's, when efficient control policies were enforced, leading to a decrease in emissions. Gold mining, on the other hand was nearly insignificant as a Hg source up to the late 1970's, but presently isresponsible for over 80% of total emissions. Presently, over 115 tons of Hg are released into the atmosphere in Brazil annually. Nearly 78 tons come from gold mining operations, 12 tons come from chlor-alkali industry and 25 tons come from all other industrial uses. Inputs to soils and waters however, are still unknown, due to lack of detailed data base. However, emissions from diffuse sources rather than well studied classical industrial sources are probably responsible for the major inputs of mercury to these compartments.