中国城市化进程中的城市道路交通碳排放研究

探讨了中国城市化、经济发展、技术进步等与城市道路交通碳排放之间的长期均衡关系与动态作用机制,并对中国城市道路交通碳排放进行了预测和情景分析。结果表明:①城市化率、交通能源强度、城市居民消费水平和人均GDP对城市道路交通碳排放的长期均衡弹性分别为0.93、0.73、0.68、0.44;②城市道路交通碳排放的最大贡献者在中短期内是交通能源强度,长期内是城市化率;③人均GDP增长率的提高,短期内会促使城市道路交通碳排放增长率提高,而长期又有助于使之降低;④中国城市道路交通碳排放持续增长的趋势在相当长时期内不可避免;⑤不同的发展理念和政策与技术的组合,可以使城市道路交通碳排放发生重大变化。基于研究,提出了中国城市道路交通碳减排的政策取向。     

AN Amazon Perspective on the Forest-Climate Connection: Opportunity for Climate Mitigation, Conservation and Development?

Amazonia contains more carbon (C) than a decade of global, human-induced CO₂ emissions (60–80 billion tons). This C is gradually being released to the atmosphere through deforestation. Projected increases in Amazon deforestation associated with investments in road paving and other types of infra-structure may increase these C emissions. An increase of 25–40% in Amazon deforestation due to projected road paving could counterbalance nearly half of the reductions in C emissions that would be achieved if the Kyoto Protocol were implemented. Forecasted emission increases could be curtailed if development strategies aimed at controlling frontier expansion and creating economic alternatives were implemented. Given ancillary benefits and relative low costs, reducing deforestation in Amazonia and other tropical areas could be an attractive option for climate mitigation. Projects that help contain deforestation and reduce frontier expansion can play an important role in climate change mitigation but currently are not allowed as an abatement strategy under the climate regime. Creating incentives for forest conservation and decreased deforestation can be a unique opportunity for both forest conservation and climate mitigation.     

Laboratory study on sustainable use of cement–fly ash–polypropylene fiber-stabilized dredged material

The major problem associated with gravity dam was siltation of reservoir which reduced its effective water storage capacity. In order to maintain effective storage capacity of reservoir, dredging of deposits was required and dredged material was disposed of haphazardly causing damage to the sensitive environment. A better alternative could be the possibility of utilization of dredged deposits in construction works involving large quantities of material. The dredged material consisted of very fine sandy silt possessing poor geotechnical characteristics and was required to be stabilized with suitable additives before use as construction material. This laboratory investigation evaluated geotechnical properties of dredged reservoir material stabilized with cement, fly ash and fiber for its probable use as subbase in lightly trafficked roads. Compaction, unconfined compressive strength and tensile strength tests were performed on appropriate combinations of the constituent materials. The results of study revealed significant improvement in unconfined compressive strength and split tensile strength after stabilization with cement and fly ash. The unconfined compressive strength and split tensile strength of cement–fly ash-stabilized dredged reservoir material improved further upon addition of polypropylene fiber. The composite possessed the potential to be utilized as sustainable material in subbase of roads subject to further validation before application in the field. The dredging of sediments improved effective storage capacity of reservoir and increased its sustainable life period. The utilization of fly ash could diminish the environmental and economic concerns arising out of its haphazard disposal.     

The influence of geographic location on population exposure to emissions from power plants throughout China

This analysis seeks to evaluate the influence of emission source location on population exposure in China to fine particles and sulfur dioxide. We use the concept of intake fraction, defined as the fraction of material or its precursor released from a source that is eventually inhaled or ingested by a population. We select 29 power-plant sites throughout China and estimate annual average intake fractions at each site, using identical source characteristics to isolate the influence of geographic location. In addition, we develop regression models to interpret the intake fraction values and allow for extrapolation to other sites. To model the concentration increase due to emissions from selected power plants, we used a detailed long-range atmospheric dispersion model, CALPUFF. Primary fine particles have the highest average intake fraction (1 x 0(-5)), followed by sulfur dioxide (5 x 10(-6)), sulfate from sulfur dioxide (4 x 10(-6)), and nitrate from nitrogen oxides (4 x 10(-6)). For all pollutants, the intake fractions span approximately an order of magnitude across sites. In the regression analysis, the independent variables are meteorological proxies (such as climate region and precipitation) and population at various distances from the source. We find that population terms can explain a substantial percentage of variability in the intake fraction for all pollutants (R(2) between 0.86 and 0.95 across pollutants), with a significant modifying influence of meteorological regime. Near-source population is more important for primary coarse particles while population at medium to long distance is more important for primary fine particles and secondary particles. A significant portion of intake fraction (especially for secondary particles and primary fine particles) occurs beyond 500 km of the source, emphasizing the need for detailed long-range dispersion modeling. These findings demonstrate that intake fractions for power plants in China can be estimated with reasonable precision and summarized using simple regression models. The results should be useful for informing future decisions about power-plant locations and controls.     

上海市崇明岛公路两侧土壤重金属污染研究

采集了上海市崇明岛陈海、北沿公路两侧土壤和灰尘样品270余个,测定了样品的Pb、Cd、Cu、 Zn和Cr重金属含量。结果表明,陈海和北沿公路两侧土壤重金属Pb、Cd、Cu、 Zn和Cr的平均含量达到277、0279、258、918和776 mg/kg,土壤Cd污染较严重。采集的路面灰尘样品Pb、Cd、Cu、 Zn和Cr的平均含量达到512、049、489、209和970 mg/kg,超过土壤背景值2~4倍,是土壤重金属的主要二次污染源。公路防护林体系较差的北沿公路路侧土壤纵向剖面（垂直于公路走向）重金属含量随距路肩距离增加呈指数下降,土壤重金属重污染区在距路肩15 m范围内。防护林体系较完善的陈海公路距路肩15 m范围内土壤重金属污染较小,土壤重金属重污染区出现在距路肩20~50 m范围内。     

山区县乡公路建设对沿线景观格局的影响研究——以昆明市东川区蒋家沟小流域为例

公路建设对区域的各种生态过程、灾害活动等影响引起广大学者的关注,目前对小尺度区域公路沿线景观格局的影响效应研究较少。利用3S技术对云南省昆明市东川区蒋家沟小流域内县乡级公路沿线三期影像的景观进行分类和制图,运用Fragstats3.3软件和景观指数计算方法,从斑块和景观两个层次上研究公路建设前后景观格局的变化。结果表明:(1)不同时期建设公路及全部公路沿线均出现坡耕地显著减少、梯田显著增加的趋势;在不同距离梯度上,针叶林、灌丛、坡耕地景观百分比不断降低,梯田、草地面积增加。(2)公路沿线景观格局动态变化则表现为:在斑块层次上,1973年前建设公路沿线景观形态更复杂,破碎化程度高,1973年后建设公路沿线阔叶林、针叶林斑块数量增加,破碎化趋势明显;在景观层次上,公路沿线景观多样性增加,景观内部连通性降低,整体景观格局破碎化加剧,但1973年前建设公路沿线空间连接性有所提升,1973年后建设公路沿线则表现出空间连接性下降的趋势,公路全线两侧150 m范围对景观水平指数的影响最大。     

城市道路典型绿带结构对总悬浮颗粒物的净化效应

机动车道和非机动车道之间的隔离绿化带（简称机非隔离绿化带）对由机动车辆造成的空气总悬浮颗粒物（TSP）有较显著的净化效应。以典型结构类型的机非隔离绿化带为研究对象,通过布点采样测定空气中TSP浓度,定量地研究了道路绿化带对TSP的净化效益。同时,用郁闭度和疏透度表征了道路绿化带的配置情况,并研究其与TSP净化效率的相关性;采用灰色关联分析方法,初步探讨了TSP净化效率与温度、相对湿度、风速的相关性。结果表明：主干道机非隔离绿化带的最优结构是乔灌结构、次干道最优结构是乔灌草结构、支路3种结构类型的道路绿化带对TSP净化效率差异不明显;绿化带疏透度在10％~20%时,郁闭度在75％~90%,绿化带对TSP净化效率较高;相对湿度对TSP净化效率的影响较风速和温度大     

The use of construction equipment productivity rate model for estimating fuel use and carbon dioxide (CO2) emissionsCase study: bulldozer,excavator and dump truck

Carbon dioxide (CO₂) emission has drawn a great attention in recent years all over the world, and it plays a very important role in the process of global warming. The off-road equipment, which includes construction equipment, accounted for 7.5% emission of CO₂. The objective of this article is to propose a groundwork for a methodology that can be used to estimate the total fuel use and CO₂ emissions from construction equipment activities based on its productivity rate. Currently, there is not a methodology or technique for estimating productivity, fuel use and emissions at once. The multiple linear regression analysis has successfully modelled the productivity rate and good to be used as a benchmark for estimating fuel use and CO₂ emissions from various types of construction equipment performing earthwork activities. The proposed methodology will help the contractor to estimate the total expected pollutant emissions for the project, which would be valuable information for a preliminary environmental assessment of the project. By using construction plans and specifications, the methodology and tool presented in this research can be used to estimate cost, fuel use and emissions from commercial, residential, industrial or heavy highway. By the proposed approach, it is possible to develop new fuel use and emissions inventories for construction industry in general.     

Air flow and concentration fields at urban road intersections for improved understanding of personal exposure

This paper reviews the state of knowledge on modelling air flow and concentration fields at road intersections. The first part covers the available literature from the past two decades on experimental (both field and wind tunnel) and modelling activities in order to provide insight into the physical basis of flow behaviour at a typical cross-street intersection. This is followed by a review of associated investigations of the impact of traffic-generated localised turbulence on the concentration fields due to emissions from vehicles. There is a discussion on the role of adequate characterisation of vehicle-induced turbulence in making predictions using hybrid models, combining the merits of conventional approaches with information obtained from more detailed modelling. This concludes that, despite advancements in computational techniques, there are crucial knowledge gaps affecting the parameterisations used in current models for individual exposure. This is specifically relevant to the growing impetus on walking and cycling activities on urban roads in the context of current drives for sustainable transport and healthy living. Due to inherently longer travel times involved during such trips, compared to automotive transport, pedestrians and cyclists are subjected to higher levels of exposure to emissions. Current modelling tools seem to under-predict this exposure because of limitations in their design and in the empirical parameters employed.     

Analysis of material stock accumulation in China’s infrastructure and its regional disparity

Materials stocked in infrastructure provide necessary personal and economic services, and are also closely linked with massive resource extraction, energy consumption and waste generation. To support policy deliberations toward regional harmony and sustainable development, this paper examines the temporal change during 1978–2008 and spatial patterns of ten types of materials stocked in four major infrastructures (residential buildings, roads, railways, and water pipelines) in 31 provinces in China, and diagnoses regional disparity and driving factors by Theil index and multivariable regression based on panel data. It was found that the total material stock has boomed to 42.5 billion tons in 2008, with its per capita level increased by nine times over that in 1978. Over 90 % of materials are concentrated in residential buildings and roads, and are spatially inclined to decrease from coastal regions to inland areas. Since China has shifted its strategy from an inclined to harmonious regional development, the overall inequality of per capita material stock has been changing toward equality with its scale contributed mainly by inter-regional inequality, and downward trend affected dominantly by intra-regional inequality. To balance the growth speed across regions meanwhile, to develop economy and attract foreign investment in each region, would be a promising route towards reducing regional inequality. Moreover, the enhancement of governmental performance and construction of each sector’s share would also be effective for decreasing inter-regional gaps.     

The cause and consequences of road mortality of herpetofauna in durgapur,West Bengal,India

The mortality rate of herpetofauna due to road accidents in one of the busiest tarmacked metalled roads of Durgapur, an industrial town of West Bengal, India was studied. Road survey for 27 days covering a total distance of 94.5 km was conducted. Within this span of time and the total stretch of road, 354 amphibians belonging to 6 species and 133 reptiles belonging to 11 species were observed to be killed in road-accidents. Among amphibians, Duttaphrynus melanostictus and amongst the reptiles Hemidactylus spp. were killed in highest numbers. The stretch of road under survey passed through different habitat patches like’s agricultural land, human habitation, dumping area, fragmented forest and wetland. On an average, 18 herpetofauna was noted to be killed daily. It was difficult to identify the species as the key characters were missing in the remains in a few cases of road casualties. High road mortality of herpetofauna would surely affect the balance of adjoining ecosystems as well as may be crucial for the local herpetofaunal population attributes.     

Replacing car trips by increasing bike and public transport in the greater Barcelona metropolitan area: A health impact assessment study

ObjectiveEstimate the health risks and benefits of mode shifts from car to cycling and public transport in the metropolitan area of Barcelona, Spain.MethodsWe conducted a health impact assessment (HIA), creating 8 different scenarios on the replacement of short and long car trips, by public transport or/and bike. The primary outcome measure was all-cause mortality and change in life expectancy related to two different assessments: A) the exposure of travellers to physical activity, air pollution to particulate matter < 2.5 μm (PM2.5), and road traffic fatality; and B) the exposure of general population to PM2.5, modelling by Barcelona Air-Dispersion Model. The secondary outcome was a change in emissions of carbon dioxide.ResultsThe annual health impact of a shift of 40% of the car trips, starting and ending in Barcelona City, to cycling (n = 141,690) would be for the travellers who shift modes 1.15 additional deaths from air pollution, 0.17 additional deaths from road traffic fatality and 67.46 deaths avoided from physical activity resulting in a total of 66.12 deaths avoided. Fewer deaths would be avoided annually if half of the replaced trips were shifted to public transport (43.76 deaths). The annual health impact in the Barcelona City general population (n = 1,630,494) of the 40% reduction in car trips would be 10.03 deaths avoided due to the reduction of 0.64% in exposure to PM2.5. The deaths (including travellers and general population) avoided in Barcelona City therefore would be 76.15 annually. Further health benefits would be obtained with a shift of 40% of the car trips from the Greater Barcelona Metropolitan which either start or end in Barcelona City to public transport (40.15 deaths avoided) or public transport and cycling (98.50 deaths avoided).The carbon dioxide reduction for shifting from car to other modes of transport (bike and public transport) in Barcelona metropolitan area was estimated to be 203,251 t/CO₂ emissions per year.ConclusionsInterventions to reduce car use and increase cycling and the use of public transport in metropolitan areas, like Barcelona, can produce health benefits for travellers and for the general population of the city. Also these interventions help to reduce green house gas emissions.     

基于ARIMA和BP神经网络组合模型的我国碳排放强度预测

预测我国碳排放强度的长期变动趋势, 对国家进行宏观经济管理和节能减排工作具有重要的参考价值。运用深入分析自回归移动平均模型和神经网络的特性,并在此基础上建立ARIMA模型和BP神经网络组合模型,将碳排放强度的时间序列的数据结构分解为线性和非线性残差部分,对我国碳排放强度的变化趋势进行了综合分析与预测。结果显示:今后10 a我国碳排放强度总体是逐步下降的,但到2020年我国碳排放强度仅比2005年下降34%,比我国政府提出碳排放强度下降40%~45%的目标还有一定的差距。因此,要在2020年实现我国碳排放强度目标,必须要调整宏观经济政策,采取各种政策措施以实现目标     

高炉渣资源化生产绿色建材的环境效益评估——基于生命周期的视角

高炉渣是钢铁厂高炉炼铁产生的矿渣,具有较高的资源化价值,可用于生产多种绿色建材产品。熔融高炉渣经水急冷后形成的粒化高炉矿渣,粉磨成矿渣微粉可作为水泥混合材和混凝土掺合料。以高炉渣资源化过程为研究对象,采用生命周期清单分析方法,并基于GaBi 4软件平台,对我国某建材企业综合利用高炉渣生产矿渣硅酸盐水泥和商品混凝土全过程的能源消耗、原材料消耗和温室气体排放进行了分析,进而从节能、降耗和碳减排三方面评估其环境效益。结果表明,与普通硅酸盐水泥相比,矿渣硅酸盐水泥可分别实现节约能源1 911 MJ/t(节能26%),降低原材料消耗1 158 kg/t(降耗27%),减少碳排放236 kg/t(碳减排26%);与复合硅酸盐水泥相比,矿渣硅酸盐水泥可实现节约能源352 MJ/t(节能6%),降低原材料消耗278 kg/t(降耗8%),减少碳排放47 kg/t(碳减排7%)。与不掺加矿粉的普通商品混凝土比较,掺矿粉的商品混凝土可实现节约能源97 MJ/m3(节能5%),降低原材料消耗7 kg/m3(降耗0.3%),减少碳排放12 kg/m3(碳减排5%)。高炉渣资源化生产矿渣硅酸盐水泥和商品混凝土具有明显的环境效益。     

中国西北寒旱区农牧民生活碳排放评估

围绕碳排放权开展的气候谈判愈来愈关注贫困人口与弱势群体的生存权与发展权,一方面由于受制于其薄弱的社会经济水平,贫困人口与弱势群体在气候变化实践中表现出更高的脆弱性,另一方面则因气候变化减缓与适应行动而造成的贫困人口生活成本的增加以及生活水平的下降。然而,对这些地区和人口的排放权判断主要基于国家层面和地区层面宏观数据的分析,其结果掩盖了国家和地区内部不同社会经济水平下的人口排放差异,不能准确揭示贫困人口和脆弱群体的低碳排放事实。本文基于国际碳排放评估对人口生活排放的需求,结合IPCC参考方法,利用投入产出分析模型构建了人口生活碳排放评价指标体系,并用于对甘肃、青海和宁夏干旱-高寒地区农牧民生活碳排放的样本调查和分析。评估表明,中国西北干旱—高寒区人口生活碳排放仅为1.85tCO2/人,其中用于满足基本生活需要的碳排放量达到87.25%。研究发现,生活在更冷(海拔更高)区域内的人口生活排放量更高;随着家庭收入的增长,人口生活排放量也随之上升;家庭成员数量越多,家庭的人均碳排放量就会越低。     

村镇路网通达性与空间出行研究——以武汉市李集镇为例

道路网络是乡村地区社会经济发展的基础。综合道路网络分析和通达性分析方法,构建路网密度、公路可达性、接近中心性、直达性等指标研究了武汉市李集镇村镇范围内各行政村路网通达性空间格局,并结合农户调查将路网通达性与村民空间出行进行关联分析。结果表明：（1）境内部分行政村道路密度低、断头路较多,导致局部地区通达性较差;（2）受地理区位和公路覆盖两方面因素影响,境内行政村接近中心性呈现出明显的核心-边缘分布模式;（3）高等级道路覆盖不足,未能形成完善的路网体系,极大限制村民的对外出行效率、出行范围,显著影响居民出行满意度,并阻碍地区农业机械化推广和农业产业规模化发展。最后,结合路网通达性特征和居民出行需求,提出李集镇道路网络整治建议,研究结果对完善农村地区道路体系研究、指导新农村建设有一定意义。     

Environmental and economic viability of Alkali Activated Material (AAM) comprising slag,fly ash and spent coffee ground

ABSTRACT

This paper presents a concept of reusing spent coffee ground (CG) as a construction material. Through creating a CG-filled Alkali Activated Material (AAM) with industrial wastes such as fly ash (FA) and slag (S), a strong recycled material was synthesised and found suitable to be used as a road subgrade fill material. Potential groundwater contamination tests were done in accordance to the Australian Standard Leaching Procedure (ASLP). The environmental analysis done on this green material shows that albeit being composed of various industrial wastes and chemicals, CG-filled AAMs in the ground will not cause adverse environmental impacts to surrounding soils and groundwater. Heavy metals and cyanide leached from the AAMs were well below hazardous thresholds. Comparing the carbon footprint of CG, it is found that recycling CG into a construction material would reduce the nett global carbon emission by reducing dependency on quarried material. Cost analyses done on CG-filled AAMs show that these AAMs are expensive to produce relative to traditional construction materials. However, as recycling technology is progressively advancing, in the future the economic value of CG-filled AAM may increase to match those of contemporary construction materials.     

土地整治驱动下土地利用和景观格局变化研究——以上海市合庆镇为例

基于上海市合庆镇土地整治项目,通过土地利用指数、空间自相关性以及景观格局指数的分析:(1)土地整治带来的区域土地利用变化情况;(2)验证土地整治是否能起到土地集聚的作用;(3)使用景观格局指数分析土地利用空间配置关系。结果表明,整治后的项目区内建设用地明显减少,耕地数量明显增加,并且土地利用程度综合指数等土地利用指数同土地整治活动之间存在相关性。使用全局空间自相关分析方法能够很好地验证土地整治活动对土地产生的集聚效应,并且在5~10m的格网尺度下采用土地利用程度修正模型能很好地反映建设用地和耕地的局部集聚效应。此外,区域由以农业活动和非农业活动并存转向以农业活动为主,"斑块-廊道-基质"的景观结构变化显著。     

Energy consumption and emission projection for the road transport sector in Malaysia: an application of the LEAP model

This study has attempted to estimate the energy consumption and emission of pollutants namely carbon dioxide (CO₂), carbon monoxide (CO), nitrogen oxides (NOx) and non-methane volatile organic compounds (NMVOC) from the road transport sector in Malaysia from the year 2012 till 2040. This was done using the long-range energy alternatives planning (LEAP) model. Estimates of energy consumption and emissions were evaluated and analysed under a business-as-usual scenario and three other alternative fuel policy scenarios of biodiesel vehicles (BIO), natural gas vehicles (NGV) and hybrid electric vehicles (HEV). The aim of this study has been to identify the potential alternative fuel policies that would be effective in reducing the future growth of road transport energy consumption and emission in Malaysia. Results indicate that the NGV scenario contributes towards the highest reduction in road transport energy consumption followed by BIO and HEV. The NGV scenario also achieves highest mitigation of emission of all the four pollutants. In the case of CO₂ emission, BIO scenario attains second highest mitigation, whereas in the event of CO, NOx and NMVOC emission, HEV scenario achieves second highest mitigation.     

Carbon‐neutral jet‐fuel re‐synthesised from sequestrated CO2

A chemical pathway combining reverse water gas shift, Fischer‐Tropsch synthesis and hydro‐cracking was considered to re‐synthesise jet fuel from CO₂ captured at high purity by oxy‐fuelling of a typical coal‐fired power station (Drax, UK). The oxygen for oxy‐fuelling and hydrogen for the fuel re‐synthesis process are sourced by electrolysis of water. According to material and energy balances , 3.1 MT/year of jet fuel and 1.6 MT/year each of gas oil and naphtha can be produced from the Drax annual emissions of 20 MT of CO₂, sufficient to supply 23% of the UK jet fuel requirements. The overall re‐synthesis requires 16.9 GW, to be sourced renewably from (offshore) wind power, and releases 4.4 GW of exothermic energy giving scope for improvements via process integration. The energy re‐synthesis penalty was 82% ideally and 95% on a practical basis. With the cost of offshore wind power predicted to reduce to 2.0 p/kWh by 2020, this ‘re‐syn’ jet fuel would be competitive with conventional jet fuel, especially if carbon taxes apply. The re‐use of CO₂ sequestrated from coal power stations to form jet‐fuel would halve the combined CO₂ emissions from the coal power and aviation sectors.