Industrial point source CO<Subscript>2</Subscript> emission strength estimation with aircraft measurements and dispersion modelling

CO₂ remains the greenhouse gas that contributes most to anthropogenic global warming, and the evaluation of its emissions is of major interest to both research and regulatory purposes. Emission inventories generally provide quite reliable estimates of CO₂ emissions. However, because of intrinsic uncertainties associated with these estimates, it is of great importance to validate emission inventories against independent estimates. This paper describes an integrated approach combining aircraft measurements and a puff dispersion modelling framework by considering a CO₂ industrial point source, located in Biganos, France. CO₂ density measurements were obtained by applying the mass balance method, while CO₂ emission estimates were derived by implementing the CALMET/CALPUFF model chain. For the latter, three meteorological initializations were used: (i) WRF-modelled outputs initialized by ECMWF reanalyses; (ii) WRF-modelled outputs initialized by CFSR reanalyses and (iii) local in situ observations. Governmental inventorial data were used as reference for all applications. The strengths and weaknesses of the different approaches and how they affect emission estimation uncertainty were investigated. The mass balance based on aircraft measurements was quite succesful in capturing the point source emission strength (at worst with a 16% bias), while the accuracy of the dispersion modelling, markedly when using ECMWF initialization through the WRF model, was only slightly lower (estimation with an 18% bias). The analysis will help in highlighting some methodological best practices that can be used as guidelines for future experiments.     

Current status and perspectives of accelerated carbonation processes on municipal waste combustion residues

The increasing volumes of municipal solid waste produced worldwide are encouraging the development of processes to reduce the environmental impact of this waste stream. Combustion technology can facilitate volume reduction of up to 90%, with the inorganic contaminants being captured in furnace bottom ash, and fly ash/APC residues. The disposal or reuse of these residues is however governed by the potential release of constituent contaminants into the environment. Accelerated carbonation has been shown to have a potential for improving the chemical stability and leaching behaviour of both bottom ash and fly ash/APC residues. However, the efficacy of carbonation depends on whether the method of gas application is direct or indirect. Also important are the mineralogy, chemistry and physical properties of the fresh ash, the carbonation reaction conditions such as temperature, contact time, CO₂ partial pressure and relative humidity. This paper reviews the main issues pertaining to the application of accelerated carbonation to municipal waste combustion residues to elucidate the potential benefits on the stabilization of such residues and for reducing CO₂ emissions. In particular, the modification of ash properties that occur upon carbonation and the CO₂ sequestration potential possible under different conditions are discussed. Although accelerated carbonation is a developing technology, it could be introduced in new incinerator facilities as a “finishing step” for both ash treatment and reduction of CO₂ emissions.     

Identifying the European Fossil Fuel Plumes in the Atmosphere Over the Northeast Atlantic Region Through Isotopic Observations and Numerical Modelling

As part of the Danish NEAREX project the origin and variability of anthropogenic atmospheric CO₂ over the Northeast Atlantic Region (NEAR) has been studied. The project consisted of a combination of experimental and modelling activities. Local volunteers operated CO₂ sampling stations, built at University of Copenhagen, for ¹⁴C analysis at four locations (East Denmark, Shetland Isles, Faroe Isles and Iceland). The samples were only collected during winter periods of south-easterly winds in an attempt to trace air enriched in fossil-fuel derived CO₂ due to combustion of fossil fuels within European countries. In order to study the transport and concentration fields over the region in detail, a three-dimensional Eulerian hemispheric air pollution model has been extended to include the main anthropogenic sources for atmospheric CO₂. During the project period (1998–2001) only a few episodes of transport from Central Europe towards NEAR arose, which makes the data set for the evaluation of the method sparse. The analysed samples indicate that the signal for fossil CO₂, as expected, is largest (up to 3.7±0.4% fossil CO₂) at the Danish location closest to the European emissions areas and much weaker (up to ∼1.5±0.6% fossil CO₂) at the most remote location. As the anthropogenic signal is weak in the clean atmosphere over NEAR these numbers will, however, be very sensitive to the assumed background ¹⁴CO₂ activity and the precision of the measurements. The model simulations include the interplay between the driving processes from the emission into the boundary layer and the following horizontal/vertical mixing and atmospheric transport and are used to analyse the meteorological conditions leading to the observed events of high fossil CO₂ over NEAR. This information about the history of the air masses is essential if an observed signal is to be utilised for identifying and quantifying sources for fossil CO₂.     

Marginal Abatement Costs and Marginal Welfare Costs for Greenhouse Gas Emissions Reductions: Results from the EPPA Model

Marginal abatement cost (MAC) curves, relationships between tonnes of emissions abated and the CO₂ (or greenhouse gas (GHG)) price, have been widely used as pedagogic devices to illustrate simple economic concepts such as the benefits of emissions trading. They have also been used to produce reduced-form models to examine situations where solving the more complex model underlying the MAC is difficult. Some important issues arise in such applications: (1) Are MAC relationships independent of what happens in other regions?, (2) are MACs stable through time regardless of what policies have been implemented in the past?, and (3) can one approximate welfare costs from MACs? This paper explores the basic characteristics of MAC and marginal welfare cost (MWC) curves, deriving them using the MIT Emissions Prediction and Policy Analysis model. We find that, depending on the method used to construct them, MACs are affected by policies abroad. They are also dependent on policies in place in the past and depend on whether they are CO₂-only or include all GHGs. Further, we find that MACs are, in general, not closely related to MWCs and therefore should not be used to derive estimates of welfare change. We also show that, as commonly constructed, MACs may be unreliable in replicating results of the parent model when used to simulate GHG policies. This is especially true if the policy simulations differ from the conditions under which the MACs were simulated.     

Modelling and assessing inter-regional trade of CO2 emission reduction units

A cost-efficient way to allocate carbon dioxide (CO₂) emission reductions among countries or regions is to harmonise their marginal reduction costs. This could be achieved by a market of emission reduction units (ERUs). To model such a market, we use a multi-regional MARKAL-MACRO model. It gives insights into the consequences of co-ordinating CO₂ abatement on regional energy systems and economies. As a numerical application, we assess the establishment of a market of ERUs among three European countries for curbing their CO₂ emissions.     

Does the high–tech industry consistently reduce CO2 emissions? Results from nonparametric additive regression model

China is currently the world's largest carbon dioxide (CO₂) emitter. Moreover, total energy consumption and CO₂ emissions in China will continue to increase due to the rapid growth of industrialization and urbanization. Therefore, vigorously developing the high–tech industry becomes an inevitable choice to reduce CO₂ emissions at the moment or in the future. However, ignoring the existing nonlinear links between economic variables, most scholars use traditional linear models to explore the impact of the high–tech industry on CO₂ emissions from an aggregate perspective. Few studies have focused on nonlinear relationships and regional differences in China. Based on panel data of 1998–2014, this study uses the nonparametric additive regression model to explore the nonlinear effect of the high–tech industry from a regional perspective. The estimated results show that the residual sum of squares (SSR) of the nonparametric additive regression model in the eastern, central and western regions are 0.693, 0.054 and 0.085 respectively, which are much less those that of the traditional linear regression model (3.158, 4.227 and 7.196). This verifies that the nonparametric additive regression model has a better fitting effect. Specifically, the high–tech industry produces an inverted “U–shaped” nonlinear impact on CO₂ emissions in the eastern region, but a positive “U–shaped” nonlinear effect in the central and western regions. Therefore, the nonlinear impact of the high–tech industry on CO₂ emissions in the three regions should be given adequate attention in developing effective abatement policies.     

Economic effects of CO2 fertilization of crops: transforming changes in yield into changes in supply

Increasing concentrations of atmospheric carbon dioxide CO₂ have a beneficial effect on crop production that would tend to offset some of the economic losses that might be generated in some areas by the climatic effects of atmospheric CO₂ and other greenhouse gases. Previous estimates of the economic benefits of CO₂ fertilization on world crop production, however, were based on the assumption that percent changes in supply are equal to percent changes in yield. This assumption is not valid, however, because it confounds changes in supply with changes in quantity supplied. This error leads to an overestimation of the real economic benefits of CO₂ fertilization by 61–166%. The effects of CO₂ fertilization on crop production, therefore, will reduce some of the potential damages caused by the climatic impacts of greenhouse gases, but by significantly less than that indicated in earlier research.     

Meta-Modeling to Assess the Possible Future of Paris Agreement

In the meta-modeling approach, one builds a numerically tractable dynamic optimization or game model in which the parameters are identified through statistical emulation of a detailed large scale numerical simulation model. In this paper, we show how this approach can be used to assess the economic impacts of possible climate policies compatible with the Paris Agreement. One indicates why it is appropriate to assume that an international carbon market, with emission rights given to different groups of countries will exist. One discusses the approach to evaluate correctly abatement costs and welfare losses incurred by different groups of countries when implementing climate policies. Finally, using a recently proposed meta-model of game with a coupled constraint on a cumulative CO₂ emissions budget, we assess several new scenarios for possible fair burden sharing in climate policies compatible with the Paris Agreement.     

Methodology of CO2 emission evaluation in the life cycle of office building façades

The construction industry is one of the greatest sources of pollution because of the high level of energy consumption during its life cycle. In addition to using energy while constructing a building, several systems also use power while the building is operating, especially the air-conditioning system. Energy consumption for this system is related, among other issues, to external air temperature and the required internal temperature of the building. The façades are elements which present the highest level of ambient heat transfer from the outside to the inside of tall buildings. Thus, the type of façade has an influence on energy consumption during the building life cycle and, consequently, contributes to buildings' CO₂ emissions, because these emissions are directly connected to energy consumption. Therefore, the aim is to help develop a methodology for evaluating CO₂ emissions generated during the life cycle of office building façades. The results, based on the parameters used in this study, show that façades using structural glazing and uncolored glass emit the most CO₂ throughout their life cycle, followed by brick façades covered with compound aluminum panels or ACM (Aluminum Composite Material), façades using structural glazing and reflective glass and brick façades with plaster coating. On the other hand, the typology of façade that emits less CO₂ is brickwork and mortar because its thermal barrier is better than structural glazing façade and materials used to produce this façade are better than brickwork and ACM. Finally, an uncertainty analysis was conducted to verify the accuracy of the results attained.     

The impact of FDI in the OECD manufacturing sector on CO2 emission: Evidence and policy issues

This work investigates the sign and the magnitude of the impact Foreign Direct Investment (FDI) inflowing in the manufacturing sector of the countries from the Organisation for Economic Co-operation and Development (OECD) exerts on the environment and, specifically, on the amount of CO₂ from sectoral fuel combustion. By gathering data from various international institutions for those countries from 1989 to 2016, an equation model is built to take into separate account technique, scale and cumulative effects of FDI on CO₂ and analysed through the panel data technique. The positive relationships found for all these effects would highlight a detrimental role of FDI on the environment. However, the very low magnitude of the estimated coefficients and the observation that the negative impact of FDI on CO₂ decreases as the scale of its inflow increases, leads to a reconsideration of those arguments against the enforcement of international investment policies in the sector due to the environmental implications generally assumed. This positive environmental spillover is explained by referring to FDI as a driving force of technology innovation and, consequently, a way through which the implementation of more environmentally-friendly and cleaner production modes occurs. Results are consistent across different estimators and robust to a number of alternative specifications and additional co-variates.     

Air quality effects of traffic in a canyon-like street (Falmouth,U.K.)

It has been suggested that in relation to air quality impacts, roads with low (<20 000 vpd) traffic flow need not be consideredas significant. This study examines this suggestion more closelyby comparing real-time monitoring of traffic related pollutants (NO₂, PM₁₀ and PAH) at two sites (including a `canyon-street') in Falmouth, Cornwall in relation to traffic flow. For comparison, real-time monitoring data for NO₂ and PM₁₀ is also taken from a well ventilated site in Camelford, Cornwall. The data obtained suggest that roads with traffic flow considerably lower than 20 000 vpd can give rise topollutant levels which have implications for human health. The application of simple linear regression techniques to the datasuggests that under certain conditions simple estimates can be made in relation to likely traffic-related air quality effects in canyon-like streets.     

Modeling photocatalytic destruction of the organic contaminants in continuous stir flow reactor

Thin-film technique is becoming an industry standard for the preparation of TiO₂-based photocatalyst for organic destruction. The catalyst provides several advantages over the conventional powder TiO₂ in the treatment of wastewater and groundwater. In this study, a continuous stir flow reactor model is developed capable of describing the photocatalytic process. The model incorporates the following fundamental mechanisms: adsorption, diffusion, liquid-film transfer, UV attenuation, and photocatalytic reaction. All of the simulation results indicate that there exists a highly nonlinear relation between each of these parameters and the destruction rate. Various incident light intensities also are incorporated to simulate the energy efficiency. The simulations illustrate that the photocatalytic model can be used to elucidate the effect of process variables. It is also possible to “custom-design” a catalyst for the treatment of a particular waste stream.     

夏季上海城区大气中二氧化碳浓度特征及相关因素分析

利用连续自动监测仪器,获得CO2源区上海城区2010年夏季高时间分辨率的CO2连续监测数据.监测期间CO2平均浓度为414±16ppm,高于同期全球本底观测站约6%,与中国其他城市化地区的浓度水平基本相当或略低.CO2浓度日变化呈显著早晚双峰特征;周变化呈显著的波浪形,高值集中出现在工作日.除O3外,与其他污染物呈显著...     

基于GOSAT卫星的中国CO2浓度时空特征分析

采用温室气体观测卫星(GOSAT) 傅里叶变换光谱仪(FTS)发布的CO₂柱浓度L₃级别数据集产品,利用TCCON地基站点的CO₂柱浓度数据对卫星遥感数据进行验证,分析中国CO₂柱浓度时空变化特征及其影响因素。研究结果表明,GOSAT卫星的CO₂柱浓度产品精度较高,线性回归的r²为0.99,线性方程斜率为0.98,平均偏差为0.11 mg/L。中国CO₂柱浓度呈现逐年增长的趋势,存在12个月的周期性季节性变化。2010、2020年区域年平均CO₂柱浓度分别约为389.30、412.62 mg/L,增长了23.32 mg/L,年平均增长率大约为0.58%。中国区域大气CO₂柱浓度的月变化存在明显的时空差异,最大值和最小值分别出现在4月和8月,2020年4月和8月的区域平均值分别为415.09、409.13 mg/L。中国区域CO₂柱浓度从东部沿海向西部逐级递减,且呈现明显的季节性变化,夏季高值主要集中在东南部沿海地区,冬季高值主要集中在华北地区。     

Combining policy instruments for sustainable energy systems: An assessment with the GMM model

An assessment of the impact of an illustrative portfolio of policy instruments that address different sustainability concerns in the global energy system in areas of climate change, air pollution and introduction of renewable-energy resources is conducted. The effects of a policy set containing three instruments, implemented either individually or in combination, were examined. The policy instruments under examination in this work include: Cap-and-Trade policies imposing a CO₂ emission reduction target on the global energy system, a renewable portfolio standard that forces a minimum share of renewable electricity generation, and the internalisation of external costs of power generation associated with local pollution. Implementation of these policy instruments significantly changes the structure and environmental performance of the energy sector, and particularly the structure of the electric-generation sector. The positive effects are amplified when the policy instruments are simultaneously applied, illustrating the potential for synergies between these energy-policy domains. The analysis has been conducted with the multi-regional, energy-system Global MARKAL Model (GMM), a “bottom-up” partial-equilibrium model that provides a detailed representation of energy technologies and endogenizes technology learning. ^★A preliminary version of this paper has been presented at the 6th IAEE European Energy Conference on “Modelling in Energy Economics and Policy”, 1–3 September 2004, ETH Zürich, Switzerland.     

TiO2 nanoparticles influence on the environmental performance of natural and recycled mortars: A life cycle assessment

The World Meteorological Organization has recently reported that greenhouse gases have reached their highest level since 3–5 million years ago. A continuing rise would cause serious consequences e.g., rising temperatures, death of living beings, or water pollution. Cement is associated with those levels since its production encompasses around 8% of global CO₂ emissions. To increase the environmental performance of cementitious materials, different approaches could be followed, for instance, the reuse of waste materials such as recycled aggregate (RA) or the addition of TiO₂ nanoparticles due to its proactive effect during service life. However, no research has been found that examined the effect of nano-TiO₂ addition on recycled mortars in terms of environmental impact. Consequently, the main objective of this research is to evaluate the sustainability of TiO₂ nanoparticles in mortars made with either natural or recycled aggregate. Twelve mixtures with different percentages of nano-TiO₂ substitution (0%, 0.5%, 1%, 2% by the weight of cement) and RA replacement (0%, 50%, 100%) were studied. A life cycle assessment focused on material production (cradle-to-gate) was performed. The functional unit (FU) used was 1 m³ of mortar with a given compressive strength. The mix design was modified to meet the fixed strength defined in the FU. In terms of global warming potential, mortars with RA reduced the environmental impact when 0.5% of nano-TiO₂ was added. Considering waste generation and depletion of natural resources play a crucial role in the sustainability assessment of mortars with RA. Furthermore, when the compressive strength factor was considered in the FU, RA increased the total CO₂ emissions due to the higher amount of cement needed. Finally, despite the apparent harmful effect of nano-TiO₂ using a cradle-to-gate approach, these nanoparticles could highly enhance environmental performance due to their effects during service life.     

Short-Term Forecasting of Nitrogen Dioxide (NO<Subscript>2</Subscript>) Levels Using a Hybrid Statistical and Air Mass History Modelling Approach

A novel hybrid model has been developed to support the provision of real-time air quality forecasts. Statistical techniques have been applied in parallel with air mass history modelling to provide an efficient and accurate forecasting system with the ability to identify high NO₂ events, which tend to be the episodes of most significance in Ireland. Air mass history modelling and k-means clustering are used to identify air mass types that lead to high NO₂ levels in Ireland. Trajectory matching techniques allow data associated with these air masses to be partitioned during model development. Non-parametric regression (NPR) has been applied to describe nonlinear variations in concentration levels with wind speed, direction and season and produce a set of linearized factors which, together with other meteorological variables, are employed as inputs to a multiple linear regression. The model uses an innovative integrated approach to combine the NPR with the air mass history modelling results. On validation, a correlation coefficient of 0.75 was obtained, and 91 % of daily maximum (hourly averaged) NO₂ predictions were within a factor of two of the measured value. High pollution events were well captured, as indicated by strong agreement between measured and modelled high percentile values. The model requires only simple input data, does not require an emission inventory and utilises very low computational resources. It represents an accurate and efficient means of producing real-time air quality forecasts and, when used in combination with forecaster experience, is a useful tool for identifying periods of poor air quality 24 h in advance. The hybrid approach outlined in this paper can easily be applied to produce high-quality forecasts of both NO₂ and additional pollutants at new locations/countries where historical monitoring data are available.     

Availability of disaggregated greenhouse gas emissions from beef cattle production: A systematic review

Agriculture is a significant source of anthropogenic greenhouse gas (GHG) emissions, and beef cattle are particularly emissions intensive. GHG emissions are typically expressed as a carbon dioxide equivalent (CO₂e) ‘carbon footprint’ per unit output. The 100-year Global Warming Potential (GWP₁₀₀) is the most commonly used CO₂e metric, but others have also been proposed, and there is no universal reason to prefer GWP₁₀₀ over alternative metrics. The weightings assigned to non-CO₂ GHGs can differ significantly depending on the metric used, and relying upon a single metric can obscure important differences in the climate impacts of different GHGs. This loss of detail is especially relevant to beef production systems, as the majority of GHG emissions (as conventionally reported) are in the form of methane (CH₄) and nitrous oxide (N₂O), rather than CO₂. This paper presents a systematic literature review of harmonised cradle to farm-gate beef carbon footprints from bottom-up studies on individual or representative systems, collecting the emissions data for each separate GHG, rather than a single CO₂e value. Disaggregated GHG emissions could not be obtained for the majority of studies, highlighting the loss of information resulting from the standard reporting of total GWP₁₀₀ CO₂e alone. Where individual GHG compositions were available, significant variation was found for all gases. A comparison of grass fed and non-grass fed beef production systems was used to illustrate dynamics that are not sufficiently captured through a single CO₂e footprint. Few clear trends emerged between the two dietary groups, but there was a non-significant indication that under GWP₁₀₀ non-grass fed systems generally appear more emissions efficient, but under an alternative metric, the 100-year global temperature potential (GTP₁₀₀), grass-fed beef had lower footprints. Despite recent focus on agricultural emissions, this review concludes there are insufficient data available to fully address important questions regarding the climate impacts of agricultural production, and calls for researchers to include separate GHG emissions in addition to aggregated CO₂e footprints.     

北京市废弃物处理温室气体排放特征

基于《2006年IPCC国家温室气体清单指南》推荐的方法，结合《省级温室气体清单编制指南（试行）》和《城市温室气体核算工具指南》的部分数据与核算范围，针对固体废弃物填埋、焚烧和废水处理等过程，核算了北京市2005-2014年废弃物处理过程中温室气体总排放量。结果表明：2005-2014年北京市废弃物处理过程温室气体总排放量呈逐渐上升趋势，2014年温室气体总排放量比2005年增长98%。10年间，固体废弃物填埋过程一直是最主要的温室气体排放源，到2014年排放量达到最大，为416.3×10⁴t二氧化碳当量（CO₂e）。废弃物填埋、废水处理和废弃物焚烧过程占总排放量的比例分别为78.5%（CO₂e质量分数，下同）、13.5%和8%。结合已有研究，系统优化国内7个典型城市废弃物处理温室气体排放因子，核算7个城市排放情况，并对比分析了北京市排放情况。