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Urban runoff pollution has become one of the major sources of water pollution. Rapid urbanization process in China has led to a significant increase in the pollution loads, which has posed great threats on the regional water environmental safety. Thus, it is of great importance to systematically analyse the characteristics of runoff pollution in some typical highly urbanized regions. Taking the Dongguan City in South China as the study area, output and spatial characteristics of the pollution emissions were investigated through a GIS-based empirical model. The results showed that the annual pollution loads of chemical oxygen demand (COD), suspended solids (SS), total nitrogen (TN) and total phosphorus (TP) exported from the city were approximately 338489, 613175, 28292 and 2824 t/a, respectively. In particular, the Songshan Lake Area in the city had the largest pollution loads, while the Water Town New Area had the least. In terms of pollution export fluxes unit area, they were highest in the Central Downtown Area (i.e. 2124, 3450, 145 and 16 kg/hm2 a for COD, SS, TN and TP, respectively) and relatively lower in the Southeastern Bordering Shenzhen Area. Enhancing the environmental management and improving the public environmental protection awareness are necessary for mitigating runoff pollution.

In this research, a grid-based NEWS model was proposed through coupling the geographic information system (GIS) with the Global NEWS model framework. The model was then applied to the Dongjiang River basin to simulate the dissolved nutrient export from this area. The model results showed that the total amounts of the dissolved nitrogen and phosphorus exported from the Dongjiang River basin were approximately 27154.87 and 1389.33 t, respectively. 90 % of the two loads were inorganic forms (i.e. dissolved inorganic nitrogen and phosphorus, DIN and DIP). Also, the nutrient export loads did not evenly distributed in the basin. The main stream watershed of the Dongjiang River basin has the largest DIN and DIP export loads, while the largest dissolved organic nitrogen and phosphorus (DON and DOP) loads were observed in the middle and upper stream watersheds of the basin, respectively. As for the nutrient exported from each subbasin, different sources had different influences on the output of each nutrient form. For the DIN load in each subbasin, fertilization application, atmospheric deposition and biological fixation were the three main contributors, while eluviation was the most important source for DON. In terms of DIP load, fertilizer application and breeding wastewater were the main contributors, while eluviation and fertilizer application were the two main sources for DOP.

Abstract A stable and reliable urban energy supply is essential for supporting sustainable regional and even national development. Further, a general definition and method is necessary to comprehensively evaluate urban energy supply security for different energy resources, identify key problems, and conduct regulations. Therefore, ecological network analysis (ENA) is introduced as a general systematic analysis tool to simulate and assess urban energy supply security, based on the idea that various components related to energy supply exist and interact in a common network. The proposed ENA model was used to evaluate and compare the security of coal, crude oil, and natural gas supplies for Beijing during 1997–2012. The evaluation included overall sustainability assessment, system property analysis, and structure analysis of energy supply systems. The results showed that the coal supply had the highest level of supply security, followed by the crude oil supply and then the natural gas supply. In addition, the crude oil supply system showed the most competitiveness in terms of the energy supply systems' properties. Scenario analysis yielded suggestions for improving urban energy supply security by maintaining energy production, increasing energy consumption within a certain range, strengthening and diversifying supply sources, and increasing strategic energy reserves. The ENA-based general model provides a useful tool for systematic evaluation of urban energy security from the supply perspective to quantitatively support urban energy management. Highlights • Ecological network analysis is applied to evaluate urban energy supply security. • A general network model of urban energy supply systems is established. • The supply security of coal, crude oil, and natural gas in Beijing are evaluated. • Different energy supply systems are compared via structure and property analysis. • Suggestions based on scenario analysis are given to improve energy supply security. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Structures of industrial sectors have significant impacts on energy intensity. • The energy intensity may be affected by uncertainties in industrial activities. • The randomness of energy intensity may lead to unexpected violation events. • Copula-based violation risk analysis can support decision-making in energy-intensity mitigation. Abstract An integrated approach was developed through incorporating a copula-based violation risk analysis into a programming model for optimizing industrial structures of urban clusters in uncertain conditions. Also, this approach can be used to support decision making about promoting advanced manufacturing sectors (AMSs) and mitigating industrial energy intensity. The advantages and the improvements of this approach lie in (a) reflecting the relationships between energy consumption and economic benefits in industrial sectors, and (b) incorporating the violation risk of the targets in energy-intensity mitigation into an optimizing model. A case study was conducted to illustrate the application of this approach in the Pearl River Delta of China, a highly urbanized area that includes the cities of Guangzhou, Shenzhen, Zhuhai, Dongguan, Huizhou, Zhaoqing, Foshan, and Jiangmen. The results indicated that under the desired industrial structures, violation risk of energy-intensity mitigation in the urban cluster of the Pearl River Delta would be indistinctive in the single-city perspective. Also, except Dongguan, Jiangmen and Zhaoqing, the cities of the urban cluster would achieve the goal for developing AMSs, based on the Industrial Plans for the 13th Five Year. [ABSTRACT FROM AUTHOR]

To improve the capabilities of conventional methodologies in supporting greenhouse gas (GHG) emission mitigation from food production under uncertain conditions, an integrated approach was developed through incorporating copula-based violation risk analysis into a general life cycle analysis (LCA) framework. This approach strengthened the applicability of LCA in terms of uncertainty and risk reflections for food systems in the background of urbanization under multiple GHG emission targets. In detail, such an approach can (a) reflect uncertainties of food production and consumption processes, (b) tackle joint probability of two correlated variables (i.e., GHG emissions and economic benefits) through the employment of Archimedean copula (i.e., Gumbel, Frank, and Clayton copula) and Gaussian copula, and (c) assess violation risk of GHG emissions in food production considering the trend of future urbanization. A case study was proposed to illustrate application of the approach in Dalian City, China. Considering uncertainties of dietary patterns in 2020, two scenarios (scenarios of baseline and increase) were proposed according to dietary structures of urban and rural residents. In detail, the scenario of baseline represented the recent dietary pattern of Dalian in 2015. Scenario of increase indicated 50% rise in beef, mutton, and milk compared with the dietary pattern under the scenario of baseline. The results showed that based on the current agenda upon GHG emission intensity in China, violation risks under the scenario of baseline would be more prominent than the violation risks under the scenario of increase. [ABSTRACT FROM AUTHOR]

In the era of climate change, life cycle analysis (LCA) has been acknowledged as a useful method for examining carbon footprints of products or services., Once captured and stored by trees and other plants, biogenic CO 2 would re-enter the atmosphere sooner or later after the use phase of the product. And many LCA studies did not calculate the temporary carbon storage in biogenic carbon. Thus, this paper proposed a hybrid LCA approach to provide a structured methodology for evaluating carbon footprint of copying paper in consideration of temporary carbon storage. The developed method was then applied to a paper mill of China. It is indicated that the hybrid LCA method could provide a comprehensive methodology for accounting carbon footprints as well as assessing effects of delaying GHG emissions. The results shows that the carbon footprint of 1000 kg copying paper was 647.89 kg CO 2 under scenario 1 and -5094 kg CO 2 under scenario 2. Concurrently, the effect of delaying the emission of the temporarily stored carbon in copying paper was 7.67%, 15.52%, or 23.58% for a certain period of time (i.e., 10, 25, or 30 years). [ABSTRACT FROM AUTHOR]

Purpose: As a useful comprehensive index for reflecting nutrient cycling in soils, nitrogen (N) and phosphorus (P) stoichiometry is subject to influences of many external environmental and biological factors. Studies on such influences were limited, and the influential mechanism remains unclear. The purpose of this research is to investigate soil N and P stoichiometric variations and analyze 'fertile island' effects of Tamarix chinensis Lour. ( T. chinensis) in the coastal wetland of Laizhou Bay in China. Materials and methods: Soil samples beneath clusters and communities of T. chinensis were collected respectively in July 2012. Amounts of ammonium, nitrate, and available phosphorus in the soil samples were measured through the corresponding standard methods for material measuring. Results and discussion: In general, there were significant vertical variations in soil N and P stoichiometry beneath clusters and communities of T. chinensis. A downtrend was observed for N and P contents with the increase in soil depth. On the contrary, the N/P ratio revealed a trend of going up first and then dropping off along with the increase of the soil depth. Comparatively, the horizontal variations in the soil N and P stoichiometry beneath a single cluster of T. chinensis were greater in the topsoil than those in the subsoil. The N and P contents gradually decreased from the canopy center to the outside. On the contrary, an opposite trend was found for the N/P ratio. For the horizontal variations beneath T. chinensis communities, there were no significant differences for either N and P contents or N/P ratios. Conclusions: Similar to the ecosystems in arid and semi-arid areas, vegetations in many semi-humid areas could also form fertile islands and exert significant influences on the soil nutrient cycle. The formation of fertile islands beneath a single cluster of T. chinensis could have significant influence on soil N and P stoichiometry. Under the influence of fertile islands beneath T. chinensis, the limiting element of the biogeochemical processes in the coastal wetland of Laizhou Bay might change from N to P. However, the influences of fertile island effects on soil N and P stoichiometry beneath T. chinensis communities were relatively small, illustrating that the influences of fertile island effects was not significant at the community level. Thus, the impacts of environmental factors on soil N and P stoichiometry might be greater than that of the fertile island effects in the wetland on a larger scale. [ABSTRACT FROM AUTHOR]

Abstract: Green GDP is an effective economic indicator of urban environmental management. This paper introduces a new method of accounting Green GDP, which puts the value of direct ecosystem services into GDP. Direct ecosystem services are weighted by their virtual prices and aggregated in the same way as market goods and services in GDP. They are components of nature, directly enjoyed, consumed, or used to yield human well-being. They belong to ecosystem services. In order to choose direct ecosystem services reasonably, two principles are put forward. That is, when calculating the value of ecosystem services for Green GDP, the differences between services for human beings and services for other living beings must be considered. And the green GDP of Wuyishan city of China is accounted, considering the direct ecological services value of urban ecosystem as environmental benefit. The results show that the value of direct ecosystem services in Wuyishan City in 2005 has reached 2.3 billion yuan RMB, and the green GDP is 15.3 billion yuan RMB. [ABSTRACT FROM AUTHOR]

Understanding the complex ways in which urbanization influences energy-environmental efficiency (EEE) is essential for achieving energy savings and emission reductions. The multidimensional impacts of urbanization on EEE were evaluated using a hybrid approach that combined a super slack-based measure (SBM) model with a stochastic impacts by regression on population, affluence, and technology (STIRPAT) model. This approach was applied to evaluate the influences of multi-dimension urbanization on EEE, taking account of undesirable outputs from environmental pollution. The appropriateness of the approach was verified using panel data of 21 cities in Guangdong Province from 2005 to 2016. The results indicated there existed obvious regional differences in the indexes of urbanization and EEE in Guangdong Province during this period. Further analysis of the multidimensional impacts of urbanization revealed that two factors (i.e., proportion of the urban resident population and urban compactness) had significant positive impacts on EEE. Conversely, the impacts of the following three factors on EEE were significant negative: (1) per capita GDP, (2) contribution of the secondary industry, and (3) proportion of land used for urban construction. Some factors (e.g., population size and urban built-up area) did not have significant effects on EEE in Guangdong Province. These findings indicated that decision makers in Guangdong Province could consider the positive influences of the population urbanization and the negative influences of the land urbanization on EEE. • The impacts of multidimensional urbanization on energy–environmental efficiency (EEE) were studied. • Imbalances in EEE within Guangdong Province were reflected. • A hybrid approach of super-SBM and extended STIRPAT model was proposed. • There were positive and negative influences from population and land urbanization on EEE respectively. [ABSTRACT FROM AUTHOR]

Highlights • A new evaluation framework of urban ecosystem health (UEH) is proposed. • UEH is evaluated from dimensions of structure, function, process and development. • The fuzzy matter-element model is established to evaluate the UEH states. • The health states of typical Chinese cities along the 'B & R' are assessed. • Suggestions are proposed to improve health states of different types of cities. Abstract As key social nodes and development engines, the status of various cities is important for the construction of "the Silk Road Economic Belt" and "21st Century Maritime Silk Road" (hereafter called the "B&R"). To comprehensively evaluate the status of cities along the B&R, the concept of urban ecosystem health was applied in this paper, and an innovative assessment framework of "structure-function-process-development" was proposed based on the understanding of the concept of urban ecosystem health. Then, four-layer assessment indicators were established to reflect the health status of urban ecosystems. Subsequently, a fuzzy matter-element model was constructed to measure the urban ecosystem health status, grade the health levels, and identify the limiting factors. A case study was conducted on 14 typical Chinese cities along the B&R. The temporal dynamics indicated that the health states of most of these cities gradually improved during the study period. With respect to spatial differences, city types could be ranked from high to low health in the order of coastal innovative and open cities, inland open cities, and open-window cities. Based on further analysis of limiting factors, suggestions to improve the ecosystem health levels of cities along the "B&R" were proposed for the different types of cities. [ABSTRACT FROM AUTHOR]

Due to frequent and serious waterlog and environmental pollution in cities in recent years, urban stormwater management (USM) has become an essential issue of urban sustainable development in China. Low Impact Development (LID) technologies are effective and popular measures of USM, and can be used to reduce urban waterlog and the associated environmental pollution. In this paper, in order to identify an optimal strategy of LID technologies based on economic efficiencies and environmental performances, the construction costs and environmental benefits of the four LID technologies (including grass swales, bioretention cells, green roofs, and permeable pavement) were analyzed. Then, due to the uncertain feature of rainfall, concentration of pollutants and many social-economic factors, an inexact fuzzy chance-constrained programming (IFCCP) model was developed. Multiple uncertainties that can be expressed as interval parameters, fuzzy sets, and stochastic distribution can be addressed effectively and incorporated directly into the modeling process. Based on the analysis of the precipitation probability distribution and land use data, the developed model was applied to a university campus with relatively high building density and plot ratio in Beijing. Then, optimal solutions of multiple precipitation probabilities ( p m ) under varying USM goals were obtained. The four LID technologies were chosen to meet multiple USM goals based on multiple p m values. When   p m = 0.1 , 0.05 , 0.02 and   0.015 , the total construction investments would be 1.46 to 4.66, 1.46 to 5.25, 2.31 to 8.54 and 3.95 to 12.7 million yuan, respectively. The relationship between construction costs and p m represented the relationship between economic benefit and system risk. The results indicated that USM was influenced by the rainfall capacity, construction costs would increase with the increase of precipitation, and the risks of constraint violation would decrease as the construction costs increase. When considering the four LID technologies during the planning stage of USM, the preferred selection order would be bioretention cells, permeable pavements, grass swales and green roofs. Therefore, the solutions under each p m level could provide the references for desired USM plans. [ABSTRACT FROM AUTHOR]

The problem of fresh water scarcity is one of the major constraints for regional development. Rapid urbanization and rising economic prosperity has further exacerbated problems with not only water quantity, but also water quality. Hence, sustainable utilization of water resources should be a priority, especially in water stressed areas. However, most current studies on optimal water allocation models are based on physical water, which cannot fully reveal the water flows embedded in imported and exported raw materials and products throughout all production processes. Thus, they fail to achieve sustainability goals. Therefore, the objective of this study was to set up an optimal water allocation model for industrial sectors based on water footprint accounting. In this paper, first the internal and external blue and gray water footprints were evaluated. The results indicated that the external water footprint was the major contributor to Dalian's water footprint, which shared around 72.58% of the total. Among all the industrial sectors, the chemical industry and chemical production sector had the highest total WF. Second, analyses of water productivity intensity of the WF and physical water for the industrial sectors were conducted. The comparison of the results revealed that physical water productivity intensity failed to explain the embedded water inflows in the production processes among the regions and sectors. Third, an optimization model based on the water footprint accounting results was thus set up. The optimal consequences indicated that a water allocation plan could meet both the water requirements for the blue and gray water footprints of the industrial sectors, and their target output goals as well. Therefore, this optimal allocation model is both rational and applicable for sustainable water utilization in future water management strategy formulations. [ABSTRACT FROM AUTHOR]

In this research, an export coefficient based dual inexact two-stage stochastic credibility constrained programming (ECDITSCCP) model was developed through integrating an improved export coefficient model (ECM), interval linear programming (ILP), fuzzy credibility constrained programming (FCCP) and a fuzzy expected value equation within a general two stage programming (TSP) framework. The proposed ECDITSCCP model can effectively address multiple uncertainties expressed as random variables, fuzzy numbers, pure and dual intervals. Also, the model can provide a direct linkage between pre-regulated management policies and the associated economic implications. Moreover, the solutions under multiple credibility levels can be obtained for providing potential decision alternatives for decision makers. The proposed model was then applied to identify optimal land use structures for agricultural NPS pollution mitigation in a representative upstream subcatchment of the Miyun Reservoir watershed in north China. Optimal solutions of the model were successfully obtained, indicating desired land use patterns and nutrient discharge schemes to get a maximum agricultural system benefits under a limited discharge permit. Also, numerous results under multiple credibility levels could provide policy makers with several options, which could help get an appropriate balance between system benefits and pollution mitigation. The developed ECDITSCCP model can be effectively applied to addressing the uncertain information in agricultural systems and shows great applicability to the land use adjustment for agricultural NPS pollution mitigation. [ABSTRACT FROM AUTHOR]

With the studies of ecological stoichiometry changing from global to regional and smaller scales, it is of great significance to know how, for a single species in a typical ecosystem, the carbon (C), nitrogen (N) and phosphorus (P) stoichiometry varies with the seasons and responds to environmental stresses. In this study, taking T. chinensis ( Tamarix chinensis Lour.) in the Laizhou Bay coastal wetland as a test object, seasonal variations in leaf C, N and P stoichiometry and their correlations with soil salt were analyzed. The results showed that leaf C, N and P contents and the ratios of C:N, C:P and N:P of T. chinensis exhibited large variations. The leaf C, N and P contents were 388.56–472.07, 18.39–32.86 and 1.02–3.16 g kg −1 , respectively. Also, the ratios of C:N, C:P and N:P were 11.83–24.78, 125.98–425.98 and 8.62–23.66, respectively. The seasonal variation of the leaf C content presented an increasing trend while the leaf N and P contents indicated a trend of first increasing and later decreasing. However, a trend contrary to the leaf N and P was observed for the ratios of leaf C:N, C:P and N:P. There was a significant negative correlation between leaf P content and soil salt. Conversely, a positive correlation was found between the ratios of leaf C:P, N:P and soil salt. Generally, T. chinensis in the Laizhou Bay wetland took a defensive life-history strategy during the growth process. The growth of T. chinensis was limited by N at the beginning of the growing season, and by P in the middle and final stages of the growing season. [ABSTRACT FROM AUTHOR]

[Display omitted] • Patch complexity and urban compactness indexes were developed to assess urban form. • The impact of urban form on PM 2.5 was explored in GBA by spatial panel models. • The complexity of urban patches had a negative effect on PM 2.5 concentrations. • The impact of urban compactness on PM 2.5 concentrations was positive. • A more complex and less compact urban form was adoptable in terms of reducing PM 2.5. Given the serious threat of PM 2.5 pollution to the environment and public health in China, reducing PM 2.5 concentrations through urban planning practices has become a common interest of urban planners and policymakers. In this regard, identifying the relationship between urban form and PM 2.5 concentrations has been a matter of much concern. This paper seeks to investigate how urban form influences PM 2.5 concentrations by taking the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as a case study. First, the urban form was assessed by two indicators, i.e., the patch complexity index (PCI) and urban compactness index (UCI), which were developed based on multiple landscape metrics and the principal component analysis. Then, the relationship between PM 2.5 concentrations and the two urban form indicators was revealed by spatial panel models. Our results mainly showed that PCI and UCI were negatively and positively associated with PM 2.5 concentrations, respectively, indicating that less compact urban forms with high patch complexity had advantages in reducing the PM 2.5 concentrations. According to these empirical results, the mixed-use urban development with high green coverage, which is conducive to constructing a more complex and less compact urban form, would be adoptable in terms of mitigating PM 2.5 concentrations in the GBA urban agglomeration. [ABSTRACT FROM AUTHOR]

• An integrated modeling approach is developed. • Multiple modeling methods were combined. • The approach is applied in a City Cluster of China. • Coordination for WEF and economy is analyzed under multiple scenarios. In this research, an integrated approach is developed through the incorporation of systems dynamics (SD), catastrophe progression (CP), and coupled coordination degree (CCD) analysis within a general modelling framework. The developed SD-CP-CCD is then employed to simulate and evaluate relationships among the water-energy-food (WEF) and the economic systems. It will improve traditional methods for WEF nexus analysis through a) incorporating urban WEF connections and changes into the cross-system coupling analysis framework, b) evaluating its coordination with economic growth and a multi-scale and regional disparity, and c) promoting policy recommendations to ensure the guarantee of urban WEF under economic growth. The approach is then verified through WEF nexus system of Urban Agglomerations of Pearl River Delta City Cluster (PRDCC) in China. Temporal and spatial characteristics of CCD in the region were analyzed. The results revealed their performance in cities with multiple economic backgrounds. Also, the fragile factors of each city were reflected by multi-scale exploration. Regional inequality and spatial agglomeration effects were considered. The results showed that CCD has noticeable temporal and spatial differences. Geographically, CCD varied from uncoordinated to high-level coordination. The eastern cities were much better coordinated than the western cities. Due to the increasing pressure of population and economic growth in the future, the upward trend of CCD would occur in most cities. The vulnerability factors of each city were explored. Simultaneously, apparent spatial inequality and agglomeration patterns were observed, with a downward trend over time. The temporal and spatial patterns of CCD revealed in this study indicated that PRDCC policymakers should formulate policies that suit the characteristics of cities and reduce the targeted regional imbalances. [ABSTRACT FROM AUTHOR]