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1.
Artigo em Alemão | MEDLINE | ID: mdl-33412605

RESUMO

Most intoxications caused by inhalation are due to carbon monoxide (CO). Usually the reasons are fires in buildings from which people cannot escape quickly enough, open fire places or carbon monoxide emissions from combustion plants. In Germany, there are more than 4000 intoxications and over 600 fatalities resulting from CO poisining every year. Although there is a general awareness of the risks associated with CO, the specific risks and especially methods of protection are not sufficiently known.


Assuntos
Intoxicação por Monóxido de Carbono , Fogo , Monóxido de Carbono/efeitos adversos , Intoxicação por Monóxido de Carbono/diagnóstico , Gases , Alemanha , Humanos
2.
Environ Monit Assess ; 193(1): 22, 2021 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-33389165

RESUMO

The prediction of dispersion of gases emitted from rooftop stacks in a built environment is important for preventing or minimizing their harmful effects on human health. In this study, the wind flow and dispersion of exhaust gas emitted from rooftop stacks on buildings in an urban environment under different atmospheric thermal stabilities were investigated using numerical simulations. The wind flow field and dispersion contaminants were simulated using a computational fluid dynamics model with the k-ε turbulent schemes being resolved by the Reynolds-averaged Navier-Stokes approach. An isolated building was modeled under conditions of varying thermal stratification of the boundary layers (neutral, unstable, and stable conditions). The diffusion flow field within the building wake zone was investigated for various stack sites (center, right side, and left side). Experiments were conducted in a wind tunnel to validate the numerical simulation results, by using the data qualitatively and quantitatively. The numerical simulation results were consistent with the experimental observations. The results indicated that the pollutant concentration of the plume spread was high near the stack and decreased with increasing distance from the stack. Under stable conditions, the flow motion and separation increased in the wake zone, and the pollutant concentration of the lateral spread at the average human height decreased. Under unstable conditions, the flow of the vortex circulation was fast and strong, and the pollutant concentration of the vertical spread was high.


Assuntos
Poluentes Atmosféricos , Monitoramento Ambiental , Poluentes Atmosféricos/análise , Simulação por Computador , Gases/análise , Humanos , Modelos Teóricos
3.
Environ Sci Pollut Res Int ; 28(2): 1565-1573, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32851524

RESUMO

In this study, the abatement of benzene in a dielectric barrier discharge (DBD) reactor was studied. The efficiency was investigated in terms of benzene conversion and product formation. The composition of gas-liquid-solid three-phase product produced during degradation was observed by GC-MS. Under the optimal SED, the solid-phase product was analyzed by FT-IR, SEM, and EDS. The results suggested that the product were mainly benzonitriles, benzenedicarbonitrile, phenols, esters, and amides. The wt% of C in product decreased as SED increased, demonstrating that the high discharge voltage facilitated the conversion of VOCs to gaseous intermediate product and CO2. Possible degradation mechanism and pathways of benzene destruction in the DBD reactor were proposed.


Assuntos
Benzeno , Gases , Cromatografia Gasosa-Espectrometria de Massas , Fenóis , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Waste Manag ; 120: 626-634, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33176939

RESUMO

The recycling of high-titanium-bearing blast furnace slag (TiO2 > 23 wt.%) is an urgent problem that has attracted global research attention. To achieve high-efficiency, low-consumption, clean, and high value-added recycling utilization, a new process is proposed herein, which entails reacting a CH4-H2-N2 gas mixture with the titanium-bearing blast furnace slag to initially produce Ti(C, N, O) at a low temperature, whereafter the product is purified and chlorinated. The effects of Fe2O3, urea, and sawdust on the reduction and carbonitriding characteristics are also investigated. The results indicate that the Fe2O3 additive can promote the formation of Ti(C, N, O), while urea and sawdust are instrumental for enhancing gas diffusion in solid powders. The proposed novel recycling process was assessed and it evinced many advantages and great feasibility.


Assuntos
Reciclagem , Titânio , Gases
5.
Waste Manag ; 120: 725-733, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33223250

RESUMO

Fast urbanization and economic prosperity generate huge amount of municipal solid waste (MSW). It is therefore critical to identify the determinants of greenhouse gas (GHG) emissions from MSW treatment and prepare potential GHG mitigation measures. A combined System Dynamics - Logarithmic Mean Divisia Index model is developed to identify the driving forces of GHG emission generated from MSW treatment and explore the mitigation potentials. Shanghai, a typical megacity in China is selected as a case study. Results showed that economic development, population scale and emission intensity were driving forces to induce GHG emissions from MSW treatment, while generation intensity and treatment structure were the factors to mitigate GHG emissions from MSW during 2000-2017. Scenario analysis further revealed that landfill gas utilization and MSW separation improvement were the most effective measures in reducing GHG emissions from MSW treatment, leading to about 88.07% and 85.48% of reduction compared with the business-as-usual scenario in 2050. Scenarios of improving incineration rate, reducing per capita MSW generation and restricting population growth will reduce GHG emissions by 72.29%, 30.06% and 0.30%, respectively. Utilizing landfill gas, improving MSW separation and promoting green behaviors are suggested to mitigate GHG emissions from MSW treatment.


Assuntos
Gases de Efeito Estufa , Eliminação de Resíduos , China , Gases/análise , Efeito Estufa , Resíduos Sólidos/análise
6.
Waste Manag ; 120: 392-399, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33261979

RESUMO

In this study, we compared the results of biomass and biocarbon content analysis of Solid Refuse Fuels using 14C method and selective dissolution method. Solid Refuse fuel Samples for biomass and biocarbon contents analysis were each collected from the silos and stack of the respective three facilities. Samples collected for 1, 10, 20, and 30 days for each method were analyzed. The analysis data were grouped into sample period, type and method and the optimum method for the detection of the biomass and biocarbon content was estimated. The biomass and biocarbon content showed a partially normal distribution. However, it does not satisfy equal variance. Therefore, we applied the parametric statistics Welch's ANOVA test and the nonparametric statistics Kruskal-Wallis test to compare the means of each sample group. The results of the Kruskal-Wallis test showed that sapmles collected over 20 days at Facility A had the same mean value. Therefore, when analyzing biocarbon content using the 14C method, conducting analyses by collecting exhaust gases for more than 20 days reduces errors in the results.


Assuntos
Incineração , Eliminação de Resíduos , Biomassa , Gases/análise , Resíduos Sólidos/análise
7.
Int J Food Microbiol ; 337: 108955, 2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33186831

RESUMO

Probabilistic topic modelling is frequently used in machine learning and statistical analysis for extracting latent information from complex datasets. Despite being closely associated with natural language processing and text mining, these methods possess several properties that make them particularly attractive in metabolomics applications where the applicability of traditional multivariate statistics tends to be limited. The aim of the study was thus to introduce probabilistic topic modelling - more specifically, Latent Dirichlet Allocation (LDA) - in a novel experimental context: volatilome-based (sea) food spoilage characterization. This was realized as a case study, focusing on modelling the spoilage of Atlantic salmon (Salmo salar) at 4 °C under different gaseous atmospheres (% CO2/O2/N2): 0/0/100 (A), air (B), 60/0/40 (C) or 60/40/0 (D). First, an exploratory analysis was performed to optimize the model tunings and to consequently model salmon spoilage under 100% N2 (A). Based on the obtained results, a systematic spoilage characterization protocol was established and used for identifying potential volatile spoilage indicators under all tested storage conditions. In conclusion, LDA could be used for extracting sets of underlying VOC profiles and identifying those signifying salmon spoilage, giving rise to an extensive discussion regarding the key points associated with model tuning and/or spoilage analysis. The identified compounds were well in accordance with a previously established approach based on partial least squares regression analysis (PLS). Overall, the outcomes of the study not only reflect the promising potential of LDA in spoilage characterization, but also provide several new insights into the development of data-driven methods for food quality analysis.


Assuntos
Microbiologia de Alimentos/métodos , Modelos Estatísticos , Salmo salar/microbiologia , Alimentos Marinhos/microbiologia , Animais , Microbiologia de Alimentos/normas , Qualidade dos Alimentos , Armazenamento de Alimentos , Gases/análise , Metabolômica , Compostos Orgânicos Voláteis/análise
8.
Chemosphere ; 266: 128943, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33218733

RESUMO

The performance of UV-activated Fe2O3-containing ZSM-5 (UFZ5) and silica (UFS) as adsorbents for the removal of low concentration of volatile organic sulfur compounds (VOSCs) was investigated in ambient conditions. A ∼99.9% and ∼89.2% removal of 10 ppm DMDS was observed for UFZ5 and UFS, respectively, due to a higher proportion of iron in UFZ5. The N2 adsorption isotherm confirmed an unpredictable increase in the surface area and pore volume of adsorbents after the fifth adsorption-oxidation cycle, which made adsorbents highly reusable for multiple cycles. The spectroscopic analysis predicted an increase in the hydroxyl density along with the resistance of catalytic sites against sulfur deactivation, which favored the adsorption-oxidation process. The adsorption capacity of UFZ5 remained in the range of 0.12-0.22, 0.26-0.48, 0.40-0.75 mg g-1 for methyl mercaptan (MM), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS), respectively which were significantly higher than those calculated for UFS. The analysis confirmed SO2, CO, CH3OH, H2O, and elemental S as by-products. The UFZ5 was found competent and robust for the treatment of VOSCs-contaminated indoor air.


Assuntos
Poluição do Ar , Compostos Orgânicos Voláteis , Adsorção , Gases , Enxofre , Compostos de Enxofre/análise , Compostos Orgânicos Voláteis/análise
9.
Sci Total Environ ; 759: 143529, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33229076

RESUMO

Carbon capture and sequestration technologies are used to reduce carbon emissions. Membranes, solvents, and adsorbents are the three major methods of CO2 capture. One of the promising methods is the use of algae to absorb CO2 from flue gases and convert it into biomass. Algae have great potential as renewable fuel sources and CO2 capture using photosynthesis for carbon fixation has also attracted much attention. This paper presents an extensive and in-depth report on the utilization of algae for carbon capture and accumulation. This is done in conjunction with cultivating the algae for the production of biomass for biodiesel production. Different systems are investigated for algae cultivation as well as carbon capture to effectively mitigate carbon emissions. The performance and productivity of these biosystems depend on various conditions including algae type, light sources, nutrients, pH, temperature, and mass transfer. Macroalgae and microalgae species were explored to determine their suitability for carbon capture and sequestration, along with the production of biodiesel. The steps for producing biodiesel were comprehensively reviewed, which are harvesting, dehydrating, oil extraction, oil refining, and transesterification. This technology combines active carbon capture with the potential of biodiesel production.


Assuntos
Biocombustíveis , Microalgas , Biomassa , Dióxido de Carbono , Gases
10.
J Environ Manage ; 280: 111677, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33243624

RESUMO

This study evaluated the transport mechanisms and emission rates of landfill gas (LFG) from 200- (vegetated with short grass), 300- (vegetated with short grass), and 450-mm-thick (non-vegetated) interim cover soils within a municipal solid waste landfill. LFG emission and diffusion mechanisms were evaluated using static flux chambers and laboratory-scale diffusion columns. Overall, the greatest CH4 and CO2 emissions were consistently observed from the 200-mm-thick cover soil with an average flux rate of 39.2 mg m-2 h-1 and 3.07 × 103 mg m-2 h-1, respectively. In addition to CH4 and CO2, H2S migration through a 450-mm interim cover soil was also evaluated. The H2S emission rate was relatively more uniform at an average of 2.47 × 10-5 mg m-2 h-1. Long-term LFG emission was predicted using an emission model based on a first-order decomposition rate equation and compared with the static flux chamber method. The field-measured CO2, CH4 and H2S emissions were less than the estimated emissions from the emission model, by 22%, 85%, and 91%, respectively. Further, the diffusion coefficients of CH4, CO2, and H2S for the interim cover soils were determined using a laboratory-scale diffusion column test and compared with a three-parameter diffusion model. The measured and estimated diffusion coefficients for the three landfill gases were within the 10% variation limits. Based on these findings, the LFG emission rate varied depending on the physical-chemical properties of the cover soil (e.g., cover thickness, moisture content, compaction ratio, uneven distribution of soil), organic material content and age of buried refuse, and seasonal environmental conditions (such as temperature). Test results showed that fugitive CH4 emissions can be reduced one fourth by utilizing an appropriate cover soil (300-mm to 450-mm, CL) compared to cases with a thinner cover soil.


Assuntos
Eliminação de Resíduos , Solo , Gases/análise , Metano , Instalações de Eliminação de Resíduos
11.
J Hazard Mater ; 402: 123472, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-32731115

RESUMO

The public has started to increasingly scrutinize the proper disposal and treatment of rapidly growing medical wastes, in particular, given the COVID-19 pandemic, raised awareness, and the advances in the health sector. This research aimed to characterize pyrolysis drivers, behaviors, products, reaction mechanisms, and pathways via TG-FTIR and Py-GC/MS analyses as a function of the two medical plastic wastes of syringes (SY) and medical bottles (MB), conversion degree, degradation stage, and the four heating rates (5,10, 20, and 40 °C/min). SY and MB pyrolysis ranged from 394.4 to 501 and from 417.9 to 517 °C, respectively. The average activation energy was 246.5 and 268.51 kJ/mol for the SY and MB devolatilization, respectively. MB appeared to exhibit a better pyrolysis performance with a higher degradation rate and less residues. The most suitable reaction mechanisms belonged to a geometrical contraction model (R2) for the SY pyrolysis and to a nucleation growth model (A1.2) for the MB pyrolysis. The main evolved gases were C4-C24 alkenes and dienes for SY and C6-C41 alkanes and C8-C41 alkenes for MB. The pyrolysis dynamics and reaction pathways of the medical plastic wastes have important implications for waste stream reduction, pollution control, and reactor optimization.


Assuntos
Gases/química , Resíduos de Serviços de Saúde , Plásticos/química , Pirólise , /epidemiologia , Cromatografia Gasosa-Espectrometria de Massas , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Termogravimetria
12.
Bioresour Technol ; 319: 124169, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33254445

RESUMO

In this work, the hydrogen-oxidizing bacterium Cupriavidus necator H16 was engineered for trehalose production from gaseous substrates. First, it could be shown that C. necator is a natural producer of trehalose when stressed with sodium chloride. Bioinformatic investigations revealed a so far unknown mode of trehalose and glycogen metabolism in this organism. Next, it was found that expression of the sugar efflux transporter A (setA) from Escherichia coli lead to a trehalose leaky phenotype of C. necator. Finally, the strain was characterized under autotrophic conditions using a H2/CO2/O2-mixture and other substrates reaching titers of up to 0.47 g L-1 and yields of around 0.1 g g-1. Taken together, this process represents a new way to produce sugars with high areal efficiency. With further metabolic engineering, an application of this technology for the renewable production of trehalose and other sugars, as well as for the synthesis of 13C-labeled sugars seems promising.


Assuntos
Cupriavidus necator , Dióxido de Carbono , Cupriavidus necator/genética , Gases , Hidrogênio , Trealose
13.
Chemosphere ; 265: 128965, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33248729

RESUMO

There is evidence that polycyclic aromatic hydrocarbons (PAHs) and human gut microbiota are associated with the modulation of endocrine signaling pathways. Independently, studies have found associations between air pollution, land cover and commensal microbiota. We are the first to estimate the interaction between land cover categories associated with air pollution or purification, PAH levels and endocrine signaling predicted from gut metagenome among urban and rural populations. The study participants were elderly people (65-79 years); 30 lived in rural and 32 in urban areas. Semi-Permeable Membrane devices were utilized to measure air PAH concentrations as they simulate the process of bioconcentration in the fatty tissues. Land cover categories were estimated using CORINE database and geographic information system. Functional orthologues for peroxisome proliferator-activated receptor (PPAR) pathway in endocrine system were analyzed from gut bacterial metagenome with Kyoto Encyclopaedia of Genes and Genomes. High coverage of broad-leaved and mixed forests around the homes were associated with decreased PAH levels in ambient air, while gut functional orthologues for PPAR pathway increased along with these forest types. The difference between urban and rural PAH concentrations was not notable. However, some rural measurements were higher than the urban average, which was due to the use of heavy equipment on active farms. The provision of air purification by forests might be an important determining factor in the context of endocrine disruption potential of PAHs. Particularly broad-leaved forests around homes may reduce PAH levels in ambient air and balance pollution-induced disturbances within commensal gut microbiota.


Assuntos
Poluentes Atmosféricos , Microbioma Gastrointestinal , Hidrocarbonetos Policíclicos Aromáticos , Idoso , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Gases/análise , Microbioma Gastrointestinal/genética , Humanos , Metagenoma , Hidrocarbonetos Policíclicos Aromáticos/análise
14.
Sci Total Environ ; 756: 144154, 2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33310211

RESUMO

Inert gas is often used in the deoxygenation of microbial electrolysis cells (MECs) to maintain growth and viability of anaerobes. However, the effects of the gas atmosphere on hydrogen production and microbial community of MECs are often neglected. Here, the performances and biofilm microbiomes of MECs pre-sparged with different gases were compared. MECs pre-sparged with argon gas (Ar) yielded more hydrogen (3.73 ± 0.13 mol-H2/mol-acetate) and a higher hydrogen production rate (2.99 ± 0.17 L-H2/L-reactor-day) than MECs pre-sparged with N2 (3.41 ± 0.13 mol-H2/mol-acetate and 2.27 ± 0.28 L-H2/L-reactor-day, respectively). Microbiome analysis indicated that the relative abundance of Geobacter increased from 59.25% to 77.79% when the gas atmosphere in MECs shifted from N2 to Ar. Hydrogen production may have been catalyzed by nitrogenase from Geobacter and photosynthetic bacteria in MECs pre-sparged with Ar. These findings suggested that the gas atmosphere substantially influences the microbiome of anode biofilms and Ar sparging is most effective for enhancing hydrogen production in MECs.


Assuntos
Fontes de Energia Bioelétrica , Eletrólise , Atmosfera , Eletrodos , Gases , Hidrogênio
15.
Chemosphere ; 263: 127920, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32822936

RESUMO

Arsenic (As) and selenium (Se) pollution caused by coal combustion is receiving increasing concerns. The environmental impacts of As/Se are determined not only by stack emission but also by leaching process from combustion byproducts. For a better control of As/Se emission from As/Se-enriched coal combustion, this study investigated the migration and emission behavior of As/Se in a circulating fluidized bed (CFB) power plant equipped with fabric filter (FF) and wet flue gas desulfurization (WFGD) system. The results demonstrated that arsenic was both enriched in bottom ash (41.4-47.6%) and fly ash (52.4-58.6%), while selenium was mainly captured by fly ash (73.9-83.4%). Limestone injection into furnace promoted As/Se retention in ash residues. Arsenic was mainly converted into arsenate in high-temperature regions and partly trapped in bottom ash as arsenite. In contrast, selenium capture mainly occurred in low-temperature flue gas by the formation of selenite, because of the poor thermal stability of most selenite. Triplet-tank method can totally remove arsenic in WFGD wastewater. And 18.4-58.7% of selenium was removed, resulting from the precipitation of Se4+ anions with highly soluble Se6+ anions remaining in wastewater. The concentrations of As and Se in the stack emission were 0.25-1.02 and 0.96-2.24 µg/m3, receptively. The CFB boiler equipped with FF + WFGD was shown to provide good control of the As/Se emission into the atmosphere. Leaching tests suggested that more attention should be paid to As leachability from fly ash/gypsum, and Se leachability from gypsum/sludge.


Assuntos
Poluentes Atmosféricos/análise , Arsênico/análise , Centrais Elétricas , Selênio/análise , Atmosfera , Leitos , Carbonato de Cálcio , Sulfato de Cálcio , Carvão Mineral/análise , Cinza de Carvão/química , Monitoramento Ambiental , Gases
16.
Sci Total Environ ; 753: 141690, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32896730

RESUMO

Biomass, as a renewable energy source, has high potential for supplying the energy needs of modern societies. Gasification is a thermochemical route for converting biomass into combustible gas at high temperatures. The main purpose of the present study was to develop an Aspen Plus model of air-steam gasification of biomass (sawdust) to predict the gasification characteristics and performances. The prediction capability of the model was evaluated by comparison with experimental data obtained in a fluidized bed biomass gasifier. First, the influence of gasification temperature on gas composition, product yields and gasifier performances was investigated. The biomass feeding rate and air flow rate were set at~0.445 kg/h and 0.5 Nm3/h, respectively, while the gasifier temperature was varied between 700 °C to 800 °C. With the increase of temperature, the gas yield (DGY) increased steadily from 1.72 to 2.0 Nm3/kg, while the HHV of the produced syngas (HHVgas) increased initially from 5.38 to 5.73 MJ/Nm3 and then decreased to 5.69 MJ/Nm3. After determining optimal temperature (800 °C), the influence of equivalence ratio (ER) and steam/biomass ratio (S/B) on gasification characteristics, dry gas yield (DGY) and tar yield (TRY) was studied. As ER increased from 0.19 to 0.23, TRY decreased from 9.13 g/Nm3 to 8.45 g/Nm3. In contrast, DGY initially increased from 2.02 Nm3/kg to 2.43 Nm3/kg as ER increased from 0.19 to 0.21 and then dropped to 2.24 Nm3/kg at ER of 0.23. An increase in S/B from 0.61 to 2.7 also resulted in a slight increase in HHVgas; however, TRY showed a decreasing trend (from 9.65 g/Nm3 to 8.95 g/Nm3). The results showed that the model developed in this paper is a promising tool for simulating the biomass gasification at various operating conditions.


Assuntos
Gases , Vapor , Biomassa , Hidrogênio , Temperatura
17.
Waste Manag ; 119: 39-62, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33039980

RESUMO

Trace gas emissions from municipal solid waste (MSW) landfills have received increasing attention in recent years. This paper reviews literature published between 1983 and 2019, focusing on (i) the origin and fate of trace gas in MSW landfills, (ii) sampling and analytical techniques, (iii) quantitative emission measurement techniques, (iv) concentration and surface emission rates of common trace compounds at different landfill units and (v) the environmental and health concerns associated with trace gas emissions from MSW landfills. Trace gases can be produced from waste degradation, direct volatilisation of chemicals in waste products or from conversions/reactions between other compounds. Different chemical groups dominate the different waste decomposition stages. In general, organic sulphur compounds and oxygenated compounds are connected with fresh waste, while abundant hydrogen sulphide, aromatics and aliphatic hydrocarbons are usually found during the methane fermentation stage. Selection of different sampling, analytical and emission rate measurement techniques might generate different results when quantifying trace gas emission from landfills, and validation tests are needed to evaluate the reliability of current methods. The concentrations of trace gases and their surface emission rates vary largely from site to site, and fresh waste dumping areas and uncovered waste surfaces are the most important fugitive emission sources. The adverse effects of trace gas emission are not fully understood, and more emission data are required in future studies to assess quantitatively their environmental impacts as well as health risks.


Assuntos
Poluentes Atmosféricos , Eliminação de Resíduos , Poluentes Atmosféricos/análise , Gases , Metano/análise , Reprodutibilidade dos Testes , Resíduos Sólidos , Instalações de Eliminação de Resíduos
18.
Waste Manag ; 119: 135-144, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33059163

RESUMO

The management of municipal solid waste (MSW) in Malaysia has been mainly focused on collection, transportation and disposal of MSW. To examine the contribution of MSW management to GHG emissions, Intergovernmental Panel on Climate Change (IPCC) 2006 Waste Model was used by deploying Tier 2 method. It estimated that 6,898,167 tonnes CO2-eq of GHG emissions were released in 2016 from solid waste disposal sites (SWDS) and are projected to increase to 9,991,486 tonnes CO2-eq in 2030. To reduce GHG emissions from MSW management, Solid-Waste-Management Greenhouse-Gas (SWM-GHG) calculator was used to compare different approaches. SWM-GHG calculator focused on three settings including recycling approach, incineration approach and integrated approach. According to SWM-GHG calculator, in 2016, 15,906,614 tonnes CO2-eq of GHG emissions were released by recycling approximately 16% of MSW and disposing of 84% of MSW in SWDS. Out of the three approaches, integrated approach can result in highest reduction of GHG emissions by 2050 (64%) from GHG emissions in 2016, as compared to recycling approach (50% reduction) and incineration approach (46% reduction). While, recycling has been the main national goal for last 14 years as it has increased up to 17.5% by 2016, the current Malaysian government aims to establish 8 incinerators in Malaysia that will treat approximately 32% of MSW annually. However, estimations of SWM-GHG calculator and some opportunities and threats highlighted by SWOT analysis suggest the integrated approach as the best suited approach for Malaysia for achieving significant and sustainable reductions in GHG emissions.


Assuntos
Gases de Efeito Estufa , Eliminação de Resíduos , Gerenciamento de Resíduos , Gases/análise , Efeito Estufa , Malásia , Resíduos Sólidos/análise
19.
Food Chem ; 334: 127615, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711261

RESUMO

In this review article, the state of the art of gas sensors based on quartz crystal microbalance (QCM) for fruit freshness detection is overviewed from the aspects of development history, working principle, selection and modification of sensitive materials, and volatile organic compounds detection of fruits. According to the characteristics of respiratory intensity at the stage of fruit ripening, fruits can be divided into respiration climacteric fruits and non-climacteric fruits. In recent years, research has mainly focused on respiration climacteric fruits, such as bananas and mangoes, etc., while related studies on non-climacteric fruits have been rarely reported, except for citrus fruits. The preparation methods and structure design of sensitive materials based on physical/chemical adsorption mechanisms are further discussed according to the odor components that affect the freshness of fruits, namely alkenes, esters, aldehydes and alcohols.


Assuntos
Análise de Alimentos/métodos , Frutas/química , Técnicas de Microbalança de Cristal de Quartzo/métodos , Compostos Orgânicos Voláteis/análise , Adsorção , Álcoois/análise , Aldeídos/análise , Ésteres/análise , Etilenos/análise , Análise de Alimentos/instrumentação , Qualidade dos Alimentos , Gases/análise , Odorantes/análise , Técnicas de Microbalança de Cristal de Quartzo/instrumentação
20.
Chemosphere ; 262: 127295, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32536422

RESUMO

Good air quality is documented as a significant factor of social justice. The human health hazards associated with air pollution are not distributed equally across cities; the most vulnerable people are more exposed to ambient air as they commute to work and wait for buses or trains at the stations. Aerosols play important roles in atmosphere quality and the climate; their oxidation at the nanoscale level may possibly increase the reactivity and toxicity of atmospheric particulates. Indoor school environments are characterized by high concentrations of different airborne particulate and gaseous pollutants. The documentation of nanoparticles (NPs), ultra-fine particles (UFPs), and micron-size particle species present in indoor primary schools are an important aspect in the recognition of their influence in respirational difficulties and decreased cognitive progress in children. This work utilizes the study of condensed water, sampled with portable dehumidifiers (PD), to describe NPs and UFPs in the vapor stage of enclosed zones. The acquired extracts were analyzed by advanced electron microscopy techniques. A total of 392 NPs and 251 UFPs were examined in a set of 22 samples acquired in moderately limited or inadequately ventilated indoor areas from several schools. Noting that NPs-related disorders happen at particular places of respirational structure, identification of site-specific NPs accumulation should be anticipated in direction to better verify the corresponding human health outcomes resulting from respirable NPs.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Nanopartículas/análise , Aerossóis/análise , Poluição do Ar/análise , Atmosfera , Criança , Cidades , Poeira , Monitoramento Ambiental/métodos , Gases , Humanos , Veículos Automotores , Tamanho da Partícula , Material Particulado/análise , Instituições Acadêmicas
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