Capability Maturity Model (CMM) method for assessing the performance of low-carbon city practice

Carbon emissions are considered as major factor affecting sustainable urban development. Cities have been promoting low carbon city (LCC) strategies to reduce carbon emissions and various methods have been introduced to assess the performance of LCC strategies. However, most of the existing assessment methods focus on overall LCC performance at city level, but the effects of individual dimensions like industrial structure and energy efficiency are ignored. The research question in this study therefore is whether an alternative method can be established to measure both the overall and dimensional LCC performance. This paper introduces a method for assessing LCC performance by using Capability Maturity Model (CMM), which is called LCC-CMM. The proposed method of LCC-CMM can help identify LCC maturity grade through assessing the performance of individual LCC dimensions which contributes to overall performance. There are four procedures in applying LCC-CMM, including to identify the Key Process Areas (KPAs) in the context of LCC, denoted as LCC-KPAs, to define the indicators for measuring the performance of LCC-KPAs, to calculate the performance score for each LCC-KPA, and to define criteria for specifying different grades of LCC capability maturity. The proposed method is proven effective through a case demonstration. The method can help policy makers to identify weak areas in LCC practice and introduce tailor-made policy measures to improve the weak areas.     

中国高精度温室气体排放清单编制研究进展

高精度温室气体排放清单是摸清区域碳排放来源、识别时空演变特征的数据基础，也是政府部门科学制定“减污降碳”策略、实现“双碳”目标的科技支撑。通过调研国内外组织机构、科研团队在高精度排放清单方面的成果，从核算范围、核算方法、时空化方法、评估与校验4个方面介绍了我国温室气体排放清单编制方法的研究进展。针对我国高精度温室气体排放清单研究区域分散、方法与格式不统一的问题，提出我国清单编制要逐步统筹本地化、精细化和动态化的发展建议。     

Characterizing the generation and spatial patterns of carbon emissions from urban express delivery service in China

Express delivery services, as an indispensable part of our daily life, have grown rapidly because of the booming e-commerce and logistics industries. Accordingly, there is increasing concern about the environmental load from delivering letters and parcels, such as road freight transportation emissions and packaging waste, which have not been seriously considered in previous work. In this study, a spatially based dynamic model has been created to quantify the impacts (measured in carbon emissions, CO₂eq.) from the express delivery sector in China. Specifically, intracity (urban) express delivery services—delivery and pick-up services located within the same city—was chosen for analysis. The results indicated that the carbon emissions from the transportation phase of the express delivery sector in Chinese cities varied from 20 t to 4000 t in 2017, of which 18% was attributable to the weight of extra packaging materials. Carbon emission intensities for all cities showed a close relationship with their socioeconomic status. For example, the spatial pattern of intracity express delivery volumes and associated carbon emissions showed a significant clustering property: high-value cities were clustered in eastern China and low-value cities in western China. Furthermore, the carbon hotspots were mainly located in the Yangtze River Delta and Pearl River Delta urban agglomerations. Overall, our research method and preliminary findings could be helpful for the green development of the booming express delivery sector in China and beyond.     

基于区域环境空气质量和碳排放数据的减污降碳协同效果评估

化石燃料燃烧产生的温室气体与大气污染物具有同根同源性,但具体治理中减污降碳的协同效果尚不明确。以浙江省11个设区市为研究样本,对环境空气质量和二氧化碳(CO₂)排放数据进行分析研究,结果显示：2016—2020年浙江省环境空气质量持续改善,但CO₂排放总量仍处于增长阶段。11个设区城市PM_2.5年均浓度降幅在26%～41%之间,二氧化氮(NO₂)年均浓度下降趋势不明显,大部分城市呈现碳排放增加、NO₂浓度下降的特征,只有杭州和温州两市呈现碳排放总量和NO₂、PM_2.5浓度协同下降的趋势。因子相关性分析结果表明,各设区市呈现NO₂浓度与碳排放相关性较大、协同性强,PM_2.5浓度与碳排放相关性较小的特点。进一步通过减污降碳协同定量评价分析表明,浙江地区在环境空气质量改善和温室气体减排已表现出一定成效,但各设区市因产业结构、环境基础条件、协同程度等不同导致减污降碳综合绩效有明显差异。从源头减排实现...     

Can buildings sector achieve the carbon mitigation ambitious goal: Case study for a low-carbon demonstration city in China?

China is committed to peaking its carbon emissions by 2030 and become a carbon-neutral society by 2060. The building sector that accounts for over one-third of the total carbon emissions is expected to face a great challenge in helping China achieve this goal. Shenzhen, as a low-carbon pilot city, whether its low-carbon work of urban buildings reaches the target is crucial. An attempt has been made in this study to assess the intensity of carbon emissions and associated reduction efficiency of urban buildings (operation stage) in Shenzhen by using the life cycle assessment method. The results show that the total carbon emissions generated from the buildings' operation stage have increased from 22 million metric tons (Mt) CO₂eq in 2005 to 42 (±13%) Mt. CO₂eq in 2019. Carbon emissions mainly result from the buildings' electricity use (79%), followed by refrigerant release emissions (12%). The energy conservation and carbon emissions reduction intensity in Shenzhen is at the middle level in China, and there is considerable space for improvement. According to scenario-based analysis, the carbon emission of the buildings sector can probably reach its peak by 2025 with the implementation of suitable policies – 5 years earlier than national target by 2030. Overall, this study makes a systemic analysis of the characteristics of urban buildings energy consumption and carbon emissions reduction, which can provide supportings for justifying the effectiveness of low-carbon activities in Shenzhen and beyond.     

Greenhouse gas mitigation in rice–wheat system with leaf color chart-based urea application

Conventional blanket application of nitrogen (N) fertilizer results in more loss of N from soil system and emission of nitrous oxide, a greenhouse gas (GHG). The leaf color chart (LCC) can be used for real-time N management and synchronizing N application with crop demand to reduce GHG emission. A 1-year study was carried out to evaluate the impact of conventional and LCC-based urea application on emission of nitrous oxide, methane, and carbon dioxide in a rice–wheat system of the Indo-Gangetic Plains of India. Treatments consisted of LCC scores of ≤4 and 5 for rice and wheat and were compared with conventional fixed-time N splitting schedule. The LCC-based urea application reduced nitrous oxide emission in rice and wheat. Application of 120 kg N per hectare at LCC ≤ 4 decreased nitrous oxide emission by 16% and methane by 11% over the conventional split application of urea in rice. However, application of N at LCC ≤ 5 increased nitrous oxide emission by 11% over the LCC ≤ 4 treatment in rice. Wheat reduction of nitrous oxide at LCC ≤ 4 was 18% as compared to the conventional method. Application of LCC-based N did not affect carbon dioxide emission from soil in rice and wheat. The global warming potential (GWP) were 12,395 and 13,692 kg CO₂ ha⁻¹ in LCC ≤ 4 and conventional urea application, respectively. Total carbon fixed in conventional urea application in rice–wheat system was 4.89 Mg C ha⁻¹ and it increased to 5.54 Mg C ha⁻¹ in LCC-based urea application (LCC ≤ 4). The study showed that LCC-based urea application can reduce GWP of a rice–wheat system by 10.5%.     

An Integrated Multicriteria Decision Analysis System for Reducing Air Emissions from Mining Process

The selection of a best alternative method to minimize air pollution and energy consumption for mine sites is a critical task because it encompasses evaluation of different techniques. The aim of this paper is to select most suitable technology for mining system which helps in reducing air pollution and carbon footprints by implementing the multicriteria decision analysis (MCDA) method. The existing methods or frameworks in the mining sector, which have been used in the past to select the sustainable solution, are lacking aid of MCDA, and there is a need to contribute more in this field with a promising decision system. The MCDA method is applied as a probabilistic integrated approach for a mine site in Canada. The analysis involves processing inputs to the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) method which assists in identifying the alternatives, defining the criteria, and thus outranking of the final choice. Moreover, criteria weighting has been determined using analytical hierarchical process (AHP) method. Three categories: reduction of dust/fugitive emission control strategies, reduction in fuel consumption to minimize carbon footprint, and cyanide destruction methods are selected. The probability distributions of criteria weights and output flows are defined by performing uncertainty analysis using the Monte Carlo simulation (MCS). The sensitivity analysis is conducted using Spearman’s rank correlation method and walking criteria weights. The results indicate that the integrated framework provides a reliable way of selecting air pollution control solutions and help in quantifying the impact of different criteria for the selected alternatives.

     

A holistic approach combining factor analysis, positive matrix factorization, and chemical mass balance applied to receptor modeling

Rapid urbanization and population growth resulted in severe deterioration of air quality in most of the major cities in India. Therefore, it is essential to ascertain the contribution of various sources of air pollution to enable us to determine effective control policies. The present work focuses on the holistic approach of combining factor analysis (FA), positive matrix factorization (PMF), and chemical mass balance (CMB) for receptor modeling in order to identify the sources and their contributions in air quality studies. Insight from the emission inventory was used to remove subjectivity in source identification. Each approach has its own limitations. Factor analysis can identify qualitatively a minimal set of important factors which can account for the variations in the measured data. This step uses information from emission inventory to qualitatively match source profiles with factor loadings. This signifies the identification of dominant sources through factors. PMF gives source profiles and source contributions from the entire receptor data matrix. The data from FA is applied for rank reduction in PMF. Whenever multiple solutions exist, emission inventory identifies source profiles uniquely, so that they have a physical relevance. CMB identifies the source contributions obtained from FA and PMF. The novel approach proposed here overcomes the limitations of the individual methods in a synergistic way. The adopted methodology is found valid for a synthetic data and also the data of field study.     

Examining the uncertainty of carbon emission changes: A systematic approach based on peak simulation and resilience assessment

Efforts to achieve carbon peak is one of the Chinese government's commitments, but the diversity of future development paths leads to the uncertainty of carbon emissions. Based on the carbon peak simulation, this study develops a framework to assess the carbon emission uncertainty, aiming to explore the potential low-carbon paths. The STIRPAT model is firstly introduced to explore the influence of population, economic and technology factors on carbon emissions, which is followed by emission peaks simulation. The resilience theory is then introduced to define the concept of low-carbon resilience (LCR), which refers to the ability to maintain a low level of carbon emissions. The uncertainty of carbon emission changes between different scenarios is identified by considering peaking time, cumulative increase and mitigation process. This study taking 10 Chinese coastal provinces as an example, and results show that all provinces can achieve the target of carbon emission peak in low-emissions scenario, the cumulative growth of carbon emissions is low and can be mitigated over a relatively short term, showing a strong LCR. In high-emissions scenario, Liaoning, Tianjin, Fujian and Guangxi may not have a peak before 2050, the uncertainty of carbon emission changes is relatively high, while Hebei, Jiangsu, Shanghai and Guangdong show relatively low uncertainty for the clear peaking time. The study also designs intermediate scenario to reduce the uncertainty of carbon emission changes to provide reference for each province's emission reduction path. These findings help to understand carbon uncertainty to reduce the risk of increasing cumulative emissions under the scenario of only focusing on peaking times, and provide a basis for future carbon resilience and sustainable emission reduction policies.     

Development and Application of Urban High Temporal-Spatial Resolution Vehicle Emission Inventory Model and Decision Support System

This paper reports on the development and application of an urban high temporal-spatial resolution vehicle emission inventory model and decision support system based on the current situation in China and actual vehicle emission control requirements. The system incorporates a user-friendly modular architecture that integrates a vehicle emission model and a decision support platform and includes scenario analysis and visualisation capabilities. A bottom-up approach based on localised emission factors and actual on-road driving condition has been adopted to develop the system. As a case study of application and evaluation, an emission reduction effect analysis of the supposed low-emission zone (LEZ) policy in Beijing (2012) was conducted. According to the simulated results in the forms of tables, histograms and grid maps, the establishment of this LEZ had a definite effect on the emission reduction of various types of air pollutants, especially carbon monoxide and hydrocarbon. In the system, the simulation methodology for identifying environmental benefits brought by the LEZ policy could be used to assess other similar environmental policies. Through flexible modification of configuration values or input data variables, the efficacy of separate or joint policies could be quantifiably evaluated and graphically displayed.     

Effect of national-level spatial distribution of cities on national transport CO2 emissions

Most research regarding the relationship between cities and transportation carbon emission is focused on intra-city travel, and it has been found that compact patterns tend to emit less carbon. Yet, little is known about the impact of national-level spatial distribution of cities and inter-city transportation on transportation CO₂ emissions. Further, most studies regarding the impact of urbanization on CO₂ emission directly examine the relationship between urbanization rate and CO₂ emission with little consideration of the national spatial pattern of urbanization. This study hypothesizes that the national-level spatial distribution of cities – in a dispersed or polarized pattern – affects national transport CO₂ emissions due to the varying intensity of inter-city transportation. This study uses the Gridded Population of the World v3 and v4 from Socioeconomic Data and Applications Center (SEDAC) of NASA to examine the national-level spatial distribution of urban agglomerations. It applies the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model. The analysis shows that, among 60–90% of urbanized countries, spatially dispersed urbanized countries (e.g., countries with many medium-sized cities scattered over the territory) show a lower national transportation CO₂ emission than spatially polarized urbanized countries (e.g., there are only a few large cities). The urban system elasticity of transportation CO₂ emissions is 0.4 or 0.6. That is, if the degree of polarization decreases by 1%, national transportation CO₂ emissions decrease by approximately 0.4–0.6%. This effect is similar to the effect of GDP per capita of around 0.5%. Because it is particularly difficult to disperse people and economic activities across a country once spatial polarization is set, this study's findings have the most significant implications for urbanizing countries. If urbanizing countries adopt national urban policy and territorial plans to form dispersed cities, it could reduce transportation carbon emissions and promote sustainable development. For already urbanized countries, national urban policy development is recommended to promote spatially dispersed rather than polarized national urban systems.     

太湖流域水污染物总量减排绩效评估体系建立

在充分考虑太湖流域水污染物总量减排工作特点的前提下,采用主客观相结合的方法,选择了27个绩效评估指标,确定各评价因子的权重,构建了太湖流域水污染物总量减排绩效评估体系。在此基础上,对2005—2012年太湖流域水污染物总量减排绩效进行评估。结果表明,2010—2012年的太湖流域水污染物总量减排效果较2005—2009年有所提高,减排工作取得了较明显成效,但是距理想状态仍有一定差距。该评估体系的建立为推动流域水污染物减排绩效评估工作的发展提供了科学依据。     

Minimizing human health effects of urban air pollution through quantification and control of motor vehicular carbon monoxide (CO) in Lahore

Impact of urban air pollution has variety of focuses such as urban ecology, human health, economy, etc. But human health is always given priority. Air pollution is threat to the lives of people living in big cities of Pakistan. In Lahore only there die 1,250 people annually because of air pollution. A strong correlation exists between urban air pollution and human health in Lahore. Growth of COPD is highest among other air pollution borne diseases. Existing mass transit system (one of driving forces behind motor vehicular emission) in Lahore due to frequent stoppages, entering and exit in flow of traffic causes excess discharge of motor vehicular carbon monoxide (CO) which is a hazardous to human health. Quantification and enumeration of this discharge is essential for environmental management. The paper is an attempt to highlight human health effects of urban air pollution through correlation and regression analysis. Further it is focused upon quantifying excess motor vehicular carbon monoxide through application of simplified mobile emission model. In light of results emission control measures are recommended.     

Characterizing the long-range transport of black carbon aerosols during Transport and Chemical Evolution over the Pacific (TRACE-P) experiment

A major aircraft experiment Transport and Chemical Evolution over the Pacific (TRACE-P) mission over the NW Pacific in March-April 2001 was conducted to better understand how outflow from the Asian continent affects the composition of the global atmosphere. In this paper, a global climate model, GEOS-Chem is used to investigate possible black carbon aerosol contributions from TRACE-P region. Our result depicts that absorbing black carbon ("soot") significantly outflow during lifting to the free troposphere through warm conveyor belt and convection associated with this lifting. The GEOS-Chem simulation results show significant transport of black carbon aerosols from Asian regions to the Western Pacific region during the spring season. As estimated by GEOS-Chem simulations, approximately 25% of the black carbon concentrations over the western pacific originate from SE Asia in the spring.     

An alternative model for evaluating the balance of carrying capacity between functional urban infrastructures

Urban infrastructures commonly include four types of functional infrastructures: traditional infrastructures, greenspace infrastructures, water infrastructures, and connective infrastructures. They work as an integrated system for supporting sustainable urban development. It is therefore important for having a proper method to help understand whether there is a balance between functional urban infrastructures' carrying capacities (FUICC). This paper introduces an alternative model named FUICC Catastrophe Model (FCM) to evaluate the balance of carrying capacity between various urban infrastructures. The development of the model FCM adopts Mean-Variance Analysis (MVA) technique and Catastrophe Progression Method (CPM) collectively. The application of FCM is demonstrated by using the empirical data collected from 35 cities in China. The research findings suggest that: 1) the difference in carrying capacity of each functional infrastructure between the sample cities is significant; 2) the difference in the degree of balance between FUICC is also significant between the sample cities; 3) the sample cities are classified into four categories, namely, acceptably balanced, less balanced, poorly balanced, and unbalanced. 4) the balance performance between FUICC among Chinese cities is characterized with polarization; 5) the balance performance of carrying capacity between functional urban infrastructures is generally poor in China, 40% of the sample cities achieving acceptable performance.     

Assessment of potential impacts of municipal solid waste treatment alternatives by using life cycle approach: a case study in Vietnam

In Vietnam, most of municipal solid waste (MSW) is disposed of at open dumping and landfill sites, and the methane gas from waste is the un-ignorable source of greenhouse gas (GHG) emission. It is indispensable to explore the possibility for GHG mitigation in MSW management. The objective of this study was to estimate alternative waste treatment practices towards the GHG emission mitigation, energy consumption and generation, reduction of landfill volume, and various benefits for proposing the appropriate selection by scenario analyses for representative Vietnam’s cities. Impacts were calculated by utilizing life cycle assessment (LCA) method. A literature review survey on the current applicability of LCA database for assessing impacts from waste sector in developing countries, especially for Vietnam, was carried out. This study assessed the contribution of alternative solid waste treatment practices. The result showed that, except investment and operation costs, incineration with energy recovery seems the suitable alternative for treating waste from representative cities of Vietnam according to reduction of GHG emission and waste burden to landfill sites and energy recovery and generation. Besides, MSW composition was identified as an important factor directly influencing to impacts as well as other products and benefits of waste treatment alternatives. Reliable data on waste composition are indispensable for assessing to choose, improve, or plan the waste treatment practices towards sustainable development.     

Energy-related carbon emissions mitigation potential for the construction sector in China

China is undertaking a huge number of building and infrastructure projects. As a large consumer of energy-intensive building material, the construction activities provoke large direct carbon emissions in upstream industrial sectors (i.e. embodied carbon emissions). This paper aims to explore how construction-related climate policies could contribute to future national carbon emission mitigation efforts by employing a demand-side input-output model and scenario analysis. First, a hypothetical extraction approach is used to estimate the overall carbon emissions induced by the construction sector in the base year. Then scenario analysis is conducted to quantify the sector's technical potential for carbon mitigation in 2030 and 2050. We find that implementing construction-related climate measures in China could mitigate 2.5 Gt construction-induced CO2 in 2030, and 6.4 Gt in 2050 — more than Europe's annual total carbon emissions in 2015. More efficient electricity use could make a substantial contribution in the short-term. However, material-related initiatives, especially those focused on metal recycling, could yield significant carbon mitigation from 2030 onwards. Our findings suggest China to optimize the relationship between urbanization and construction to comply with the country's climate commitments better. Mechanisms to reform supply-side incentives, such as mandatory carbon labelling for construction material throughout the supply chain, could offer immediate benefits.     

天津生态城低碳体验中心碳排放及减碳潜力研究

基于绿色建筑评价指标体系,采用eFootprint软件对天津市中新生态城低碳体验中心全生命周期碳排放量和运营阶段采用的主要绿色技术减碳潜力进行计算与分析,结果表明:该建筑运营阶段碳排放量占比最大,为89.74％,其次是物化阶段,为10.08％,废弃阶段仅占比0.18％.同时,太阳能热水技术措施的利用对建筑的减碳效果最好...     

Influencing factors of carbon emissions in transportation industry based on CD function and LMDI decomposition model: China as an example

Globally, the transportation industry is one of the leading fields that generate the largest share of greenhouse gas emissions. While undergoing rapid development, countries worldwide aim to solve the problems involved in high energy consumption. Taking China as an example, this paper studies the main factors of carbon emissions in the transport sector and analyses the decoupling states between carbon emission and economic growth, making energy efficiency policies accordingly. In order to better demonstrate the dependence of the economy on the carbon emissions in China's transportation industry comprehensively, combined with the CD production function, this paper develops the decomposition and decoupling technology based on the LMDI approach. Additionally, it quantifies seven effects: energy emission intensity effect, energy structure effect, energy intensity effect, transportation intensity effect, technology state effect, labor input effect and capital input effect. The results show three major points: (1) From 2001 to 2018, the cumulative carbon emissions of China's transportation industry increased by 633.46 million tons, in which the capital input effect is the key factor driving carbon emissions, accounting for 157.70% of the total cumulative increased emissions, followed by energy structure effect at 10.39%. The labor input effect accounted for the smallest proportion at 2.26%. In this case, the technology state effect is the primary factor in restraining carbon emissions. During the study period, it reduced carbon emissions by 292.27 million tons, accounting for 46.14%. To a certain extent, energy intensity effect, transportation intensity effect and energy emission intensity inhibited carbon emissions, representing 16.67%, 5.32% and 2.22%, respectively. (2) During the research period, two decoupling states existed between carbon emissions and economic growth in China's transportation industry, specifically weak decoupling and expansive coupling. (3) The analysis of decomposition and decoupling state of influencing factors of carbon emissions shows that, on the one hand, factors promoting carbon emissions (capital input effect, energy structure effect and labor input effect) hinder the decoupling process. On the other hand, factors restraining carbon emissions (technology state effect, transportation intensity effect, energy intensity effect and energy emission intensity effect) accelerate the decoupling process. The research findings provide a new perspective for achieving carbon emission reduction in the transportation industry and curbing energy consumption growth.     

A brief overview of modern directions in marine DOC studies part I.--Methodological aspects

The necessity for determining the role of dissolved organic carbon (DOC) in the global carbon cycle stimulated the development of different methods of DOC analysis in aquatic environments. Progress in this direction has been made by oceanographers who developed and introduced a high-temperature catalytic oxidation (HTC) method for low organic carbon concentrations. Today this method is the reference method for marine DOC study. The combination of available reference materials and the participation in intercalibration exercises has resulted in both an increased accuracy and higher precision for this method. The HTC method completely oxidizes the more resistant DOC; makes information rapidly available following the completion of the field analysis; provides a high precision (down to 0.5 microM C); covers the range of seawater DOC concentrations (35-80 microM C and higher); with certain modifications it has proved to be both seaworthy and amenable to automated analysis; and the reliable and relatively easy to operate HTC analyzer is commercially available and easily combined with a total nitrogen analyzer for simultaneous measurements of both parameters in the same sample. In this review we summarize some aspects of sample collection, handling and the analytical chemistry of the DOC analysis by the HTC technique in marine study.