Contribution of Ecosystem Services to Air Quality and Climate Change Mitigation Policies: The Case of Urban Forests in Barcelona,Spain

Mounting research highlights the contribution of ecosystem services provided by urban forests to quality of life in cities, yet these services are rarely explicitly considered in environmental policy targets. We quantify regulating services provided by urban forests and evaluate their contribution to comply with policy targets of air quality and climate change mitigation in the municipality of Barcelona, Spain. We apply the i-Tree Eco model to quantify in biophysical and monetary terms the ecosystem services “air purification,” “global climate regulation,” and the ecosystem disservice “air pollution” associated with biogenic emissions. Our results show that the contribution of urban forests regulating services to abate pollution is substantial in absolute terms, yet modest when compared to overall city levels of air pollution and GHG emissions. We conclude that in order to be effective, green infrastructure-based efforts to offset urban pollution at the municipal level have to be coordinated with territorial policies at broader spatial scales.     

Urban Ecosystem Services for Resilience Planning and Management in New York City

We review the current state of knowledge about urban ecosystem services in New York City (NYC) and how these services are regulated, planned for, and managed. Focusing on ecosystem services that have presented challenges in NYC—including stormwater quality enhancement and flood control, drinking water quality, food provisioning and recreation—we find that mismatches between the scale of production and scale of management occur where service provision is insufficient. Adequate production of locally produced services and services which are more accessible when produced locally is challenging in the context of dense urban development that is characteristic of NYC. Management approaches are needed to address scale mismatches in the production and consumption of ecosystem services. By coordinating along multiple scales of management and promoting best management practices, urban leaders have an opportunity to ensure that nature and ecosystem processes are protected in cities to support the delivery of fundamental urban ecosystem services.     

The Dynamics of Urban Ecosystem Governance in Rotterdam,The Netherlands

We explore whether Rotterdam city has the governance capacity in terms of processes at place, and the attention in terms of vision and strategy to take up an integrated approach toward urban resilience. We adopt an interpretative policy analysis approach to assess the dynamics of urban ecosystem governance considering interviews, gray literature, and facilitated dialogues with policy practitioners. We show the inner workings of local government across strategic, operational, tactical, and reflective governance processes about the way urban ecosystems are regulated. Despite the existing capacity to steer such processes, a number of underlying challenges exist: need for coordination between planning departments; need to ease the integration of new policy objectives into established adaptive policy cycles; and need to assess the lessons learnt from pilots and emerging green initiatives. Regulating and provisioning ecosystem services receive heightened policy attention. Focus on regulating services is maintained by a policy renewal cycle that limits and delays consideration of other ecosystem services in policy and planning.     

中国城镇化加速阶段中期土地城镇化与人口城镇化的协调程度

土地城镇化与人口城镇化是否协调在过去几年倍受关注。选择了我国城镇化加速阶段中期(1996~2006年)这一时间段,通过土地利用变更调查数据,采用离差系数模型对这10 a间我国各省份土地城镇化与人口城镇化增长速度的协调性进行分析。得出的结论表明:(1)我国土地城镇化与人口城镇化增长速度总体失调,土地城镇化超前;(2)人口-土地城镇化协调程度区域差异明显,不同发展阶段的省份表现出来的人口城镇化、土地城镇化增长速度及其协调程度不一样;(3)各省份应根据自身不同的城镇化发展阶段,总结过去的经验和教训,结合当前以人为核心的新型城镇化,推进人口城镇化和土地城镇化协调发展。     

Characterization of Naturally-occurring and Anthropogenic PAHs in Urban Sediments-Wycoff/Eagle Harbor Superfund Site

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous constituents in urban sedimentary environments. The accurate characterization of their source(s) in sediments influences decisions regarding the liability for clean-up and remedial options. In this study, an extensive PAH dataset that included 50 non-alkylated (parent) and alkylated PAH groups and isomers was acquired using a modified EPA Method 8270 for the study of 5 cm intervals from 10 sediment cores (28-78 cm) obtained from the Eagle Harbor Superfund Site on Bainbridge Island, Washington. Conventional hydrocarbon "fingerprinting" and the PAH profiles in the Pb 210 age-dated cores revealed three primary PAH sources to the sediments over the past 220 years, namely (1) naturally occurring background; (2) urban runoff, and (3) creosote, the latter resulting from prior operations at the former Wyckoff wood-processing facility located on the Harbor. Naturally occurring background PAH in the pre-industrial (<1900) sediments were dominated by perylene, 1,7-dimethylphenan-threne (derived from the oxidation of abietic acid resins), and pyrogenic PAH most likely derived from historic forest fires. The concentration of PAH total in these pre-industrial sediments was consistently less than 1 mg/kg (dry). Urban runoff in the post-industrial (>1930) sediments was dominated by low but consistent concentrations (10-20 mg/kg dry) of pyrogenic PAM derived primarily from the combustion of fossil fuel(s). The creosote-impacted sediments in the post-industrialized sediments contained high concentrations (1000-140,000 mg/kg dry) of pyrogenic PAH associated with distilled, coal-derived liquids.     

Protocol Development for Assessing Arsenic Background Concentrations in Florida Urban Soils

Knowledge of arsenic background concentrations in urban soils is important for making remediation decisions. The soil cleanup target level (SCTL) for arsenic in Florida lies within the range of arsenic background concentrations. The residential SCTL is also near the practical quantification limits using analytical procedures. Currently no standard protocols are available for determining arsenic background concentrations in urban soils, apart from site-specific cases. Therefore, a pilot study was conducted to develop and employ appropriate protocols to determine arsenic distribution in urban soils. This involved: site selection (e.g. size and sampling frame), sample collection (e.g. sampling technique), and statistical considerations (e.g. design). Factors such as ease of sample collection and maintaining anonymity of private properties were also considered as they influence the successful implementation of the study. Forty surface soil samples each were collected from five categories in three land use classes (residential-yard and right-of-way, commercial and public land-parks and public building), digested using EPA method 3051a and analysed using graphite furnace atomic absorption spectrometry. Experiences from the pilot study (e.g. complications during sample selection, digestion, data censoring etc.) were used in the development of the final protocol to be used in determining the distribution of arsenic in urban areas.     

长三角地区城市建设用地扩展的水资源约束

基于资源约束理论,构建城市建设用地扩展的水资源约束模型,并测算2002-2013年期间长三角地区地级及以上城市建设用地扩展中的水资源约束强度。结果显示,研究时段内长三角地区城市建设用地扩展受到水资源的明显约束,区域建设用地扩展速度比没有水资源约束时年均下降0.35%;水资源约束强度具有空间分异规律,形成了以"苏州—杭州—宁波"、"南京—苏州"为中心地区向江苏北部和浙江南部区域逐步衰减的空间变化特征;水资源约束与城市经济总量和城市规模等级紧密相关,总体上城市经济总量大,规模等级高,建设用地扩展受水资源的约束越大。依据水资源约束强度大小将长三角地区城市归为强约束、中约束、低约束和无约束四类,发现不同类型城市在劳动力增长率、水资源供给增长率、经济产出对建设用地扩展的弹性上存在明显差异。研究还表明,即使在河网密布的长三角地区,城市用地扩展也受到水资源的约束,其他地区务必重视水资源重要性,严格遵循"以水定产、以水定城"的管理政策,提高水土资源利用效率,促进城市可持续发展。     

安徽省城市建设用地变化及驱动力分析

基于安徽省17个地级市的各类土地利用变化数据,采用典型相关分析、主成分分析和偏最小二乘回归分析等方法,分析安徽省2000~2011年建设用地的数量变化、结构变化及区域差异变化,探讨城市建设用地变化的主要驱动力。研究表明:安徽省城市建设用地面积以每年5.8%的速度不断增长;安徽省城市建设用地系统结构性增强,系统从无序向有序方向发展;从安徽省各市建设用地变化的区域特征来看,各市的建设用地相对变化率差异明显,东部、中部和南部地区变化幅度较大,西部和北部建设用地变化的幅度相对较小;居民生活水平的提高与经济发展、道路设施完善是安徽省城市建设用地变化的主要驱动力。     

The Energy for Growing and Maintaining Cities

Herein we develop a means to differentiate between the energy required to expand and the energy required to maintain the economies of cities. A nonlinear model is tested against historical data for two cities, Hong Kong and Singapore. A robust fit is obtained for Hong Kong, with energy for maintenance close to that for growth, while Singapore, with a weaker fit, is growth dominated. The findings suggest that decreases in either of the per unit maintenance or growth demands can simultaneously cause gross domestic product (GDP) and total energy use to increase. Furthermore, increasing maintenance demands can significantly limit growth in energy demand and GDP. Thus, the low maintenance demands for Hong Kong, and especially Singapore, imply that, all other things being equal, GDP and energy use of these cities will continue to grow, though Singapore’s higher energy use for growth means it will require more energy than Hong Kong.     

Distribution, availability, and sources of trace metals in different particle size fractions of urban soils in Hong Kong: Implications for assessing the risk to human health

The concentration and loading distribution of trace metals (Cu, Zn, Pb, Co, Ni, Cr, and Mn) and major elements (Al, Ca, Fe, and Mg) in different particle size fractions (2000-280, 280-100, 100-50, 50-10, 10-2, and <2 μm) of surface soils from highly urbanized areas in Hong Kong were studied. The enrichment of Pb, Cu, and Zn in the urban soils was strongly influenced by anthropogenic activities, and Pb accumulated in fine particles was mainly derived from past vehicular emissions as shown by Pb isotopic signatures. Trace metals primarily accumulated in clay, fine silt, and very fine sand fractions, and might pose potential health risks via the inhalation of resuspended soil particles in the air (PM₁₀ or PM_2.5), and ingestion of adhered soils through the hand-to-mouth pathway. The mobility, bioavailability, and human bioaccessibility of Pb and Zn in bulk soils correlated significantly with metal concentrations in fine silt and/or very fine sand fractions.