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With large volume of passengers boarding and alighting through subway platforms, the stations are getting crowded, resulting in drops in the level of service and safety concerns, especially for subway systems operating at capacity during peak hours. Thus, it is crucial for subway agencies to sense changes in travel demand and adjust their management schemes accordingly. In this paper we propose a statistical approach to estimate dynamic passenger flows with automated data. First, we develop a dynamic logistic model for calculating passenger tap-out times, which can be employed to infer passenger flow characteristics at the aggregate level. In addition, a new passenger-to-train assignment model for any subway route is derived based on the dynamic model. Subsequently, we apply an expectation-maximization algorithm to estimate the model parameters with automated fare collection and automated vehicle location data. Finally, a cross-validation method is employed to validate our approach with data obtained from several routes in Beijing subway system in China. Results of 95% prediction intervals indicate the effectiveness of the models and the proposed estimation methods. • Propose a dynamic logistic model for inferring and predicting subway passenger tap-out times. • Apply an expectation-maximization algorithm for model parameters estimation. • Develop a novel passenger-to-train assignment strategy. • No prior distributions of parameters or additional information required in the proposed methods. • Results show good effectiveness of the models and acceptable accuracy of the prediction methods. [ABSTRACT FROM AUTHOR]

In the early morning on December 17, 2020 Beijing time, China's chang'E-5 probe successfully returned to the Earth with 1731 g of lunar samples after completing drilling, shoveling, packaging of lunar soil and scientific exploration on lunar surface. It is the successful completion of the third phase of China's lunar exploration project, namely "circling, landing and returning to the moon". The scientific objectives of CE-5 mission are to carry out in situ investigation and analysis of the lunar landing region, laboratory research and analysis of lunar return samples. This paper analyzes scientific exploration tasks of CE-5 mission conducted on the lunar surface, and carries out the scientific payload system architecture design and individual scientific payload design with the scientific exploration task requirements as the target, and proposes the working mode and main technical index requirements of the scientific payloads. Based on the preliminary geological background study of the Mons Ruemker region which is the landing region of CE-5, the lunar scientific exploration and the laboratory physicochemical characterization of the return samples are of great scientific significance for our in-depth understanding of the formation and evolution of the Earth-Moon system and the chemical evolution history of the lunar surface. [ABSTRACT FROM AUTHOR]

Accurate PM 2.5 forecasting provides a possibility for establishing an early warning system to notify the public and take precautionary measures to prevent negative effects on ambient air quality and public health. Considering strong seasonal variation in meteorological conditions, in this paper, a seasonal stacked autoencoder model combining seasonal analysis and deep feature learning is proposed for forecasting the hourly PM 2.5 concentration, named DL-SSAE model. The original data are firstly decomposed into four seasonal subseries according to the Chinese calendar, and then the Kendall correlation coefficient method is employed to search inherent relationships between PM 2.5 concentrations and meteorological parameters within 1-h ahead for each seasonal time series. The inherent relationships of each seasonal subseries are finally extracted, learned, and modeled by different deep neural networks (stacked autoencoders for regression), and the hourly PM 2.5 forecasts are yielded. The addressed model is tested by the dataset collected from three environmental monitoring stations in Beijing, China. The results demonstrate that the proposed model outperforms all other considered models with/without seasonality consideration in this paper. [ABSTRACT FROM AUTHOR]

[Display omitted] • A methodological framework to delineate the provision area for the wind erosion prevention service based on the carrier dynamics of ecosystem service flows; • A computational framework to determine ecosystem service transmission pathways; • Methods to calculate the realized ecosystem service value distribution within the service provision area; • Implications on urban ecological hinterland delineation and precise ecological compensation program design. Many ecosystem service (ES) items, such as the wind erosion prevention service (WEPS), have spatially separated service provision and benefit areas (SPA & SBA), which are connected by directional ecosystem services flows (ESF). Clarifying the specific spatial relationships between the SPA and SBA is of potential scientific and policy importance for such directional flow-conveyed ES. Much of the existing research has focused on the identification of SBA based on a given SPA. However, due to the asymmetry of supply-based and demand-based ESFs and geospatial heterogeneity, this relationship cannot be directly inferred backward to obtain the SPA for a given SBA. In this paper, we propose a methodological framework along with computational methods to delineate the SPA of a given SBA. Our methods feature ESF carrier dynamics-based algorithms to determine the specific path of the ESF which is enabled by an adapted Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, as well as quantification approaches for evaluating the actual realization of ecosystem services value (RESV) with the support of the Revised Wind Erosion Equation (RWEQ) model. We demonstrate the applicability of our methods with the example of three mega-cities in northern China that are severely affected by the wind erosion problem. The results show that the spatial distribution of wind erosion source areas in the three cities are different, and the SPA based on the trajectory weights shows a decreasing trend from the city center to periphery, with those in the cities of Beijing and Taiyuan mainly concentrated in the northwestern direction, while the high RESV zones in the SPA are mainly concentrated in the desert areas. In the time series, wind erosion affecting these three cities mainly occurred in late April and May. The study provides a methodological and empirical basis for applied ecological analysis including the delineation of the ecological hinterlands of cities, or the formulation of precise ecological compensation programs. [ABSTRACT FROM AUTHOR]

In China, overlapped routes from multiple bus lines are widespread. Some buses are overcrowded while others have few passengers. The goal of this study is to reduce onboard passenger crowding without wasting bus capacity. This paper examines an extended multiple-depot vehicle scheduling problem (VSP) with multiple vehicle types. First, a bi-objective integer programming model was created. The trade-off between operating cost and passenger travel cost was established and the crowding cost due to different vehicle sizes was especially considered. Then, the capacity restraint incremental assignment algorithm and a vehicle scheduling method with multiple vehicle types were developed to find Pareto-optimal solutions that considered vehicle capacity constraints. Finally, the proposed methodology was validated using a real-world transit network in Beijing, China. The optimization results from about 1.18 million bus card swiping records show that our model and solution algorithm can effectively reduce the passenger crowding cost and avoid the waste of transport capacity. [ABSTRACT FROM AUTHOR]

Within the context of climate change and population growth, the development of urban agriculture is of great environmental and economic significance in rapidly urbanizing China. Based on the primary survey data, this paper evaluated the carbon footprint (CF) and economic efficiency of urban agriculture in Beijing (China) using the life cycle assessment method (from cradle to consumption approach). Two cases were analyzed and compared considering their differences in on-farm cultivation and off-farm supply chains: a conventional small householder farm that sells its vegetables directly to consumers in a local market, and a large home-delivery agriculture (HDA) initiative that delivers its vegetables to the consumers' home directly. Both cases were equipped with greenhouses with plastic covering but no heating system. The CF of the production, transportation and distribution of 1 kg fresh vegetables was estimated at 0.318 kg CO 2 -eq kg−1 and 0.624–0.652 kg CO 2 -eq kg−1 for conventional and HDA initiative farm, respectively. However, the HDA initiative showed a better environmental performance than the conventional operation when taking economic efficiency into consideration. The CF per unit of profit of HDA initiative (0.093–0.097 kg CO 2 -eq per CNY) was lower than conventional farm (0.111 kg CO 2 -eq per CNY). The lower CF per unit of product weight of the conventional farm was largely attributed to the high yield and the lower CF per unit of profit of the HDA initiative was mainly due to the outstanding economic profitability through income optimization. The major hotspots of CF in both cases were greenhouse plastic films in the cultivation phase (from cradle to farm gate) and transportation in the supply chain (from farm gate to consumption). Simulation of a switch to biodiesel instead of gasoline and diesel in combination with the replacement of current fossil-fuel-dominated electricity by hydro-powered electricity resulted in 20.0–21.8% reduction in the total CF. By identifying the CF hotspots of two farm cases, particular inputs and activities can be targeted for adjustment in order to effectively reduce the CF of urban agriculture in Beijing. [ABSTRACT FROM AUTHOR]

From 1990 to 2017, the number of vehicles in China increased sharply from 5 million to 310 million, and vehicle emissions became one of the major sources of air pollution. Among the main sources of PM 2.5 in Beijing, the contributions from vehicle sources increased from 5.6% (2000) to 31.1% (2012) to 45% (2017). In 2010, the CO, hydrocarbon (HC), NO x , and particulate matter (PM) emissions of yellow-label vehicles (YLVs) accounted for 46.1%, 47.9%, 63.1% and 86.1% of the total emissions from on-road vehicles. In recent years, China has been implementing a YLV scrappage subsidy policy to control air pollution, and this policy has cost several hundred billion yuan nationwide. However, China has not evaluated the costs and benefits of the policy. Many people question whether the YLV scrappage subsidy policy is worthwhile, but all the stakeholders involved complicate the process of accurately evaluating the true value of the policy. In this study, we evaluated and compared the costs and benefits of the policy in the Beijing-Tianjin-Hebei (BTH) region based on 1.362 million YLVs from 2008 to 2015. Because of the implementation of the policy, the PM 2.5 , PM 10 , NO x , CO and HC emissions in the BTH region decreased by 16.46, 18.12, 174.44, 669.11, and 91.64 kt, respectively, in 2008–2015. The results show that the policy played an important role in reducing pollutant emissions and improving environmental quality in the BTH region. The costs, benefits, and net benefits of the policy were 13.69, 34.03, and 20.34 billion yuan , respectively. The cost-benefit ratio in the BTH region was 1:2.49; at the city scale, Beijing ranked first (1:7.27), and the cost-benefit ratios of Tianjin and Hebei Province were 1:2.06 and 1:1.14, respectively. Of the 13 cities in the BTH region, Beijing had the highest net benefits, amounting to 16.43 billion yuan , while Handan City has the lowest net benefits, amounting to −0.58 billion yuan. The results may provide scientific support for the promotion of older vehicle and diesel vehicle scrappage subsidy policies, the development of cost-benefit analysis (CBA), and effective environmental decision-making in China. • Based on net number of scrappage YLVs, net benefits of the policy are calculated. • This paper estimates costs and benefits of the policy based on 1.27 million YLVs. • The costs, benefits, and net benefits are 13.69, 34.03, and 20.34 billion yuan. • The results help China promote vehicle scrappage subsidy policy on a large scale. • The results promote the development of the cost-benefit analysis in China. [ABSTRACT FROM AUTHOR]

The urban heat island effect in Beijing is significant, which has become a serious environmental problem posed to Beijing citizens. As an important measure to alleviate the urban heat island effect, cool roof is recommended in relevant Evaluation Standard for Green Building of China. In order to elicit policy implications, this paper investigates Beijing residents' willingness to pay for promoting cold roofs to alleviate the urban heat island effect and its determinants. This research applied double-bounded discrete choice format and face to face interview to elicit public's willingness to pay. 841 Beijing households were randomly selected and interviewed. For 242 (29%) respondents refuse to pay, the spike model was introduced to process the data for it has been proved to outperform the conventional model in dealing with zero responses. The average annual willingness to pay was computed as 1510.854 Chinese Yuan, which is 220.562 US dollars per household. In addition, In terms of the determinants of residents' willingness to pay, other than conventional demographic characteristics, we added and estimated covariance with regard to environmental knowledge and the theory of planned behavior. The result indicated that social norm, perceived behavior control, and previous knowledge of urban heat island effect and cool roof are statistical significantly related with residents' willingness to pay. This research suggests that timely information disclosure with regard to urban environment management and pro-environment education are urgently needed in promoting public participation in alleviating the urban heat island effect. • Willingness to pay for cool roofs for mitigating urban heat island effect is estimated. • The annual mean willingness to pay 1510.854 Chinese Yuan. • TPB theory and environmental knowledge can greatly explain pro-environment behavior. • Government credibility and education is important in promoting public participation. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates the potential expansion and impacts of Electric Vehicle (EV) market in Beijing, China at the micro level with an agent-based integrated urban model (SelfSim-EV), considering the interactions, feedbacks and dynamics found in the complex urban system. Specifically, a calibrated and validated SelfSim-EV Beijing model was firstly used to simulate how the EV market might expand in the context of urban evolution from 2016 to 2020, based on which the potential impacts of EV market expansion on the environment, power grid system and transportation infrastructures were assessed at the multiple resolutions. The results suggest that 1) the adoption rate of Battery Electric Vehicle (BEV) increases over the period, whereas the rate of Plug-in Hybrid Electric Vehicle (PHEV) almost remains the same; Furthermore, the so-called neighbour effects appear to influence the uptake of BEVs, based on the spatial analyses of the residential locations of BEV owners; 2) the EV market expansion could eventually benefit the environment, as evident from the slight decrease in the amounts of HC, CO and CO 2 emissions after 2017; 3) Charging demand accounting for around 4% of total residential electricity demand in 2020 may put slight pressure on the power grid system; 4) the EV market expansion could influence several EV-related transport facilities, including parking lots, refuelling stations, and charging posts at parking lots, in terms of quantity, layout and usage. These results are expected to be useful for different EV-related stakeholders, such as local authorities and manufacturers, to shape polices and invest in technologies and infrastructures for EVs. [ABSTRACT FROM AUTHOR]

Abstract Agricultural nonpoint source pollution (NPS) is the main water-use impairment in the upper watershed of the Miyun Reservoir in Beijing, China. Selection and placement of best management practices (BMPs) in heterogeneous watersheds, requires a multi-objective optimization framework to identify the most cost-effective conservation strategy to achieve desired water quality goals. In this paper, a novel optimization methodology was developed, utilizing a BMP database that includes BMP reduction efficiencies and costs, using a multi-objective sorting genetic algorithm (NSGA-II, nondominated sorting genetic algorithm-II) combined with the Soil Water and Assessment Tool (SWAT) served as the NPS watershed model. Cost-effectiveness curves (optimal fronts) between pollutant reduction and total net cost input were obtained for the upper watershed of Miyun Reservoir. The optimal combination of BMP, which include a combination of conservation tillage, careful timing of 30% less fertilizer application, contour planting, and use of a 10-m edge-of-field buffer strip, indicate that the least costly scenario reduced total nitrogen (TN) and total phosphorus (TP) loads by 33% at a cost of 1.02 × 106 China Yuan. The cost-effective scenario reduced TN and TP loads 44% and 68% at a cost of 2.52 × 107 and 5.64 × 107China Yuan. The greatest reduction scenario reduced TN and TP loads 55% and 76%, respectively, at a cost of 2.01 × 108 and 2.48 × 108 China Yuan. Watershed with poultry operations, required a 30% reduction in number of birds, along with a 30% reduction in the amount of manure applied was needed to achieve water quality goals. Use of the coupled BMP optimization model can assist the policy makers achieve a cost-effective implementation of best management practices to mitigate agricultural nonpoint sources at a watershed scale. Highlights • Multi-objective optimization model for the selection and placement of BMPs for nonpoint source pollution control. • Cost-effectiveness analysis for single and combination BMPs at watershed scale. • Dynamic database were development to achieve the auto-simulation of SWAT model. [ABSTRACT FROM AUTHOR]

Highlights • The first city-level building energy efficiency benchmarking system for China. • A model considering the influence of operation parameters on energy consumption. • A systematic methodology of building energy benchmarking is proposed. • The model is a valuable analysis support tool for building energy managers. Abstract The city-level public building energy efficiency benchmarking system has an important guiding value for building energy-saving work, especially for Beijing, with its high energy-consumption density and both long heating and air-conditioning periods. This paper analyzed the characteristics of large-scale office buildings in Beijing and gives a detailed description of the process of establishing a public building energy efficiency benchmarking system for large-scale office buildings in Beijing, China, including data investigation and verification, Energy Usage Intensity(EUI) calculation, determining independent and dependent variables, developing and testing the benchmarking model, and deriving the benchmarking rating table. Then the first city-level public office building energy efficiency benchmarking system in China is established based on 88 large-scale office buildings in Beijing. The results showed that the model's performance index R2 is 0.667 and gives a good representation. The process has a strong potential for replication for other cities in China and even for a national energy-consumption evaluation system. [ABSTRACT FROM AUTHOR]

Beijing, the capital of China, has experienced rapid industrialization, urbanization and motorization in recent decades. Consequently, air pollution in Beijing, especially fine particulate matter (PM 2.5 ) pollution, has gradually become a severe environmental issue, due to the continuing growth in energy consumption and the resulting multiple pollutant emissions. In response to the increasingly serious PM 2.5 pollution, Beijing's government implemented a series of policies, measures and regulations on air pollution prevention and control and took some concrete actions to improve air quality. In this paper, firstly, we summarize China's ambient air quality standards, China's policies and regulations on air pollution prevention and control. Secondly, we illustrate historical evolution and current status of air pollution in Beijing. Finally, we introduce control measures and actions in Beijing and its surrounding areas. The paper aims to help environmental scientists and policy makers around the world understand the past and current air pollution in Beijing and control strategies and actions taken by Beijing's government. [ABSTRACT FROM AUTHOR]

In previous urban planning research, the fine-grained population was considered a crucial factor. However, this population, which is generated from census data, represents only the number of people who live in a region. This static figure cannot indicate the underlying number of people and their temporal variation. Therefore, any decision-making based on the static population may be separated from reality. To overcome this difficulty, in this paper, the urban crowd flux is initially proposed and defined as the number of individuals flowing into or out of a region per unit time interval. Then, the urban crowd flux is estimated using an approach of human trajectory gridding reconstruction based on mobile phone location data. This approach is divided into three steps. First, the trajectory of each individual is extracted from sparse sampling of mobile phone location data after data cleansing. Then, combining with a road network, the trajectory of each individual is reconstructed by network interpolation based on the shortest path algorithm in regular grids. Third, we use the velocities of each user's trajectory record to estimate the urban crowd flux on spatio-temporal grids at each time slice. Finally, urban crowd flux in Beijing, China were estimated using our method and the spatio-temporal characteristics of flux is analyzed. [ABSTRACT FROM AUTHOR]

With China's rapid urbanization and industrialization, carbon emission in Chinese cities deserve special attention, and promoting low-carbon city (LCC) is considered essential for China. However, different cities present different development stages and carbon emission scenarios. This study presents the factors affecting carbon emission by introducing a city development-stage framework. The method of logarithmic mean Divisia index (LMDI) is adopted to decompose emission factors into energy structure, energy intensity, industrial structure, economic output and population scale. Beijing is chosen as the case city in this study, and four development stages for the city are identified by using the Environmental Kuznets Curve (EKC) theory, namely, S 1 (−1991), S 2 (1991–2004), S 3 (2004–2022) and S 4 (2022-). As the data collected for analysis are only available for the period of 1995–2014, this study focuses on the factor analysis for the stage S 2 and S 3 . The results show that the main driving factor for carbon emission increase in the stage S 2 is economic output, followed by population scale, while the main factor contributes to carbon emission reduction in this stage is the industrial structure. In the stage S 3 , the economic output is the top contributor to increase carbon emission, followed by population scale and energy structure, whereas energy intensity is the main influencing factor in curbing the carbon emission. Although the paper refers to the specific case of Beijing, the understanding on the driving emission factors in different development stages not only provides policy-makers and practitioners with valuable references for adopting effective measures to reduce carbon emission, but also provides other cities internationally with important lessons for accelerating the development of LCC. The innovative economic development stage framework incorporates carbon emission characteristics provides a new approach for understanding driving emission factors at city or national level. [ABSTRACT FROM AUTHOR]

In recent years, economy grows rapidly in China but it also pays a huge cost of destroy of resources and environment, and energy-saving and emission reduction has become a hot topic. This paper aims at calculating the environmental efficiency and environmental total factor productivity (TFP) of Beijing under the constraint of energy-saving and emission reduction to explore the relationship of the city’s economy and environment. We used an improved directional distance function – Biennial Directional Distance Function (BDDF) and Luenberger (L) productivity index which is corresponding to BDDF. This method can decompose the efficiency and productivity according to input and output factors and solve the problem of infeasible solution. The study found that the environmental efficiency of Beijing is different from regions and it takes on a concave distribution from the urban center to the edge of the city. Energy inputs and environmental pollution are the main influence factors of environmental inefficiency. The environmental TFP of the two central regions is higher than the two fringe regions, and through the decomposition results, we learned that the technology progress and the energy-saving emission reduction are the core of productivity growth momentum. From the change trend, the environmental efficiency of Beijing reached a high level in 2011 and followed by a slow decline. Whereas environmental TFP showed a tortuous rise trend which is down to the lowest in 2011–2012 and up to the highest in 2015. Based on our conclusions, we can say that energy-saving and emission reduction work of Beijing has made some good achievements, but with the difficulties increase we should take more reasonable measures according to the actual situation and join together to make the results of energy-saving and emission reduction work more effective. [ABSTRACT FROM AUTHOR]

Based on analysis of the wetland water resources system in Beijing city, this paper established a system dynamics (SD) model for the water resources carrying capacity (WRCC) in Beijing city. Using a computer simulation of the SD model, the variation trends from 2006 to 2030 in population, economy, water supply and demand, and pressure on the water environment were derived for Beijing, from which 12 core variables of the model were chosen as the WRCC evaluation indices. Five cases were designed in this study. The results indicate that the WRCC will continue to decline annually by following the status quo (Case 1), since the water environment will have difficulty in supporting the long-term social and economic development of Beijing. The status quo of Beijing’s socioeconomic development is therefore not sustainable. In order to address this problem, five optimization cases were put forward to improve the WRCC, and the carrying capacities and trends of the cases were compared and analyzed. Under Case 5, the WRCC (0.8 in 2030) will increase by 50%, compared to that in Case 1 (0.4 in 2030), while the water supply and demand ratio will be 20% higher than the average, and the water pollution will be 35% lower than the average in 2030. According to the analysis results, in order to guarantee sustainable utilization of water resources and social economy development in Beijing, it is necessary to increase water saving policies and pollution control investment in the future. Corresponding measures will need to be taken to ensure the implementation of water saving strategies to improve the water environment. [ABSTRACT FROM AUTHOR]

Abstract: It is not feasible to apply the traditional prediction method to predict hourly building cooling load at the urban energy planning stage because of the limited building information and complexity of energy prediction. This paper presents a simplified prediction model: Hourly Cooling Load Factor Method (HCLFM) that can provide quick and fair estimate of building cooling load for large-scale urban energy planning. The paper introduces the assumptions and principles of the proposed method, as well as discussing the implication and limitation of the approach. As a verification and demonstration, the method is applied to an office building in Beijing. The predicted results show that the dynamical trend of the cooling load is reasonable. The study further analyzes the potential causes of prediction errors and the significance of various cooling load influence factors. [Copyright &y& Elsevier]

Self-reported life satisfaction of China's population has not improved as much as expected during the economic boom, which was accompanied by a significant decline in environmental performance. Is environmental pollution the culprit for the lagging subjective well-being? To explore this issue, this paper adopts sentiment analysis to construct a real-time daily subjective well-being metric at the city level based on the big data of online search traces. Using daily data from 13 Chinese cities centred on Beijing between August 2014 and December 2019, we look at the corelation between subjective well-being and air pollution and the heterogeneity in this relationship based on two separate identification strategies. We find that air pollutants are negatively correlated with subjective well-being, and well-being tends to decline more from pollution during hot seasons. In addition, residents in wealthier regions tend to be more sensitive to air pollution. This result may be explained by the differences in the subjective perception of air pollution and personal preferences at different levels of income. These findings provide information about concerns of the public, thereby helping the government to take appropriate actions to respond to the dynamics of subjective well-being. • Sentiment analysis and big data are adopted to construct a daily city-level subjective well-being metric. • Higher levels of airborne particulates lead to a decline in subjective well-being. • Peoples' well-being tends to decline more from pollution during hot seasons. • Residents in wealthier regions tend to be more sensitive to air pollution. [ABSTRACT FROM AUTHOR]

[Display omitted] • The measurement errors in long-time series remote sensing images are corrected by statistical and spatio-temporal prediction model. • The ecological degradation of the Miyun Reservoir basin from 1985 to 2021 is mainly caused by anthropogenic factors. • Through statistical theory, the ecological development trend in the experimental area is analyzed, and the conclusion is verified by land use evolution. Miyun Reservoir, located in the Miyun District, Beijing, China, is the largest comprehensive water conservancy project and is an important ecological protection area in the North China region. Changes within the basin are the driving factors affecting the ecosystem in the watershed; therefore, it is important to analyze the changes in the ecological environment of Miyun Reservoir. For the analysis of a long time series of image data remotely sensed by satellite, the outliers caused by atmospheric, lighting, and sensor measurement errors are significant, and it is difficult for traditional algorithms to effectively recover the true image value. To address this, this paper proposes a theoretical model for predicting spatio-temporal variation based on deep learning to identify and correct invalid and anomalous values in extended time series data. This study corrected and analyzed the results of Remote Sensing based Ecological Index inversion of Landsat data of the Miyun Reservoir watershed from 1985 to 2021. The findings and conclusions of this study are important for the analysis of long time series image data from satellite remote sensing and for improving regional ecological evaluation and sustainable development planning. [ABSTRACT FROM AUTHOR]

Abstract: This paper is the second in a series of three papers aimed at understanding the emissions of vehicles in China by conducting on-board emission measurements. This paper focuses on light-duty gasoline vehicles. In this study, we measured 57 light-duty gasoline vehicles (LDGVs) in three Chinese mega-cites (Beijing, Guangzhou, and Shenzhen), covering Euro 0 through Euro IV technologies, and generated CO, HC, and NOx emission factors and deterioration rates for each vehicle technology. The results show that the vehicle emission standards have played a significant role in reducing vehicle emission levels in China. The vehicle emission factors are reduced by 47–81%, 53–64%, 46–71%, and 78–82% for each phase from Euro I to Euro IV. Euro 0 vehicles have a considerably high emission level, which is hundreds of times larger than that of Euro IV vehicles. Three old taxis and four other Euro I and Euro II LDGVs are also identified as super emitters with equivalent emission levels to Euro 0 vehicles. Of the measured fleet, 23% super emitters were estimated to contribute 50–80% to total emissions. Besides vehicle emission standards, measures for restricting super emitters are equally important to reduce vehicle emissions. This study is intended to improve the understanding of the vehicle emission levels in China, but some key issues such as emission deterioration rates are yet to be addressed with the presence of a sufficient amount of vehicle emission measurements. [Copyright &y& Elsevier]

Abstract: Firstly, this paper analyzes the basic principles and processes of the spatial pattern changes of land use in towns and villages, and the result shows that the land resource demands of urban development and population growth lead to the spatial pattern changes. Secondly, in order to grip land use changes better, the paper proposes a method for the simulation of spatial patterns. The simulating method can be divided into two parts: one is a quantitative forecast by using the Markov model, and the other is simulating the spatial pattern changes by using the CA model. The above two models construct the simulative model of the spatial pattern of land use in towns and villages. Finally, selecting Fangshan which is a district of Beijing as the experimental area, both the quantity and spatial pattern changing characteristics are investigated through building a changing dataset of land use by using spatial analysis methods based on the land use data in 2001, 2006 and 2008; CA–Markov is used to simulate the spatial pattern of land use in Fangshan for 2015. [Copyright &y& Elsevier]

Abstract: Urban containment policies, including urban growth boundaries, urban service boundaries and greenbelts, have been extensively discussed worldwide for managing urban growth. This paper focuses on the issues associated with supporting an urban containment plan and its application in China using a planning support system. The background is that the urban containment plan has been enacted as a new component of the urban plan under the City Planning Law of the People’s Republic of China. In China, the accommodating or restrictive features are integrated as control factors (CFs), which include control indicators for land-use type control, urban activity control, building height control, as well as underground development control. This paper proposes an urban containment planning support system (UC-PSS) based on ArcGIS for automatically compiling the Beijing urban containment plan considering 60 control factors with various control indicators. The compiled plan was also applied for reviewing urban master and district detail plans in Beijing supported by the UC-PSS. The effectiveness of UC-PSS was comprehensively evaluated from the perspectives of planning compilation and planning review via interviewing urban containment planners (main users of the UC-PSS) in Beijing. [Copyright &y& Elsevier]

Abstract: Based on the various fog remote sensing information products abstracted from the polar orbit meteorological satellite data (NOAA and FY), this paper analyzes the characteristics of the frequency and distribution that dense fogs have taken place in the Beijing district from 2001 to 2005. Among those information products, the statistical graph of the foggy days in Beijing from 2001 to 2005 by means of satellite remote-sensing reflects the frequency that dense fog has occurred in the different regions in Beijing; and the statistical graph of the foggy days of each season by satellite remote-sensing shows the characteristics of the temporal and spatial change of the fog distribution in Beijing in different seasons; the fog degree index(like pixel-level spatial measurement) by satellite remote-sensing reflects the fog frequency difference on unit area in different counties of Beijing. Meanwhile, based on the satellite remote-sensing pictures, data on the main meteorological elements that contribute to the formation of fog, geographic information, and DEM data, this paper makes an analysis in 3 areas, the traits of the fog distribution in the different regions of Beijing in different seasons; meteorological causes for temporal and spatial changes of the main fog types (advection fog, radiation fog). This paper also gave a brief introduction of the general principles of meteorological satellite remote sensing fog, fog information extraction method, as well as the process of satellite orbit selecting according to the ground visibility, data processing and product generation. [Copyright &y& Elsevier]

As a basic structural unit of the city, the community plays a crucial role in decreasing carbon emissions and creating a low carbon city. This paper selects a classic and official low carbon community named Min'an Community in Beijing as a case to illustrate the governance mechanism of the low carbon community in China from the perspective of polycentric governance. The paper summarizes the government mechanism, market mechanism, and public participation mechanism in Min'an Community and analyzes the provision, monitoring, and enforcement of each mechanism. We find that unlike the low carbon governance at the city or industry park levels, China's low carbon governance at the community level lacks a dominant mechanism. Even though it involves community-wide governance, the public participation mechanism is also inadequate. For improving low carbon governance at the community level, the government should broaden finance channels to strengthen the incentive mechanisms, make active use of new technologies, such as mobile Internet, encourage innovation of public participation mechanism, and employ various publicity and education measures to cultivate the low carbon culture. [ABSTRACT FROM AUTHOR]

The education of the disadvantaged population has been a long-standing challenge to education systems in both developed and developing countries. Although computer-assisted learning (CAL) has been considered one alternative to improve learning outcomes in a cost-effective way, the empirical evidence of its impacts on improving learning outcomes is mixed. This paper uses a randomized field experiment to explore the effects of CAL on student academic and non-academic outcomes for students in migrant schools in Beijing. Our results show that a remedial CAL program held out of regular school hours improved the student standardized math scores by 0.15 standard deviations and most of the program effect took place within 2 months after the start of the program. Students with less-educated parents benefited more from the program. Moreover, CAL also significantly increased the students’ interest in learning. [ABSTRACT FROM AUTHOR]

The agricultural sector is extremely vulnerable to climate change and also plays a very important role in the operation of the entire economic system, leading many studies to evaluate the possible agricultural direct economic damage (ADED) of climate change. However, this damage may have an amplification impact through the intricate industrial linkages that exist among sectors, and this impact may be even greater than the original damage. Therefore, to elucidate the economic cascading effect (ECE) in China caused by ADED and industrial linkage, this paper used the ARIO model to evaluate the total ECE and analyse the differences in the 19 sectors by taking the ADED under future annual mean temperature (AMT) increases of 1–5 °C as the input condition and adjusting the exogenous parameters to enhance the adaptability of the model; the goal was to assess the economic impact of climate change in China. The results show that (i) there is a significant amplifying impact of ECE due to industrial linkage under the influence of warming, ECE will be 4.24–5.25 times that of ADED, and the total economic impact (ADED + ECE) will exceed the GDP of the Chinese capital of Beijing in 2012 when the AMT increases by 1.5 °C, while it will exceed one tenth of China's GDP when it increases by 4 °C. (ii) Manufacturing will be the sector most affected by the industrial linkage under ADED, which accounts for 26.58% of total ECE, followed by agriculture (10.39%) and construction (8.5%). (iii) The decrease in cultivated land area will have a significant impact on the economy; when it is reduced to the minimum demand (1.41% less than 2012), ADED increases by 1.65 times and ECE increases by 2.35 times. This paper aims to provide a new perspective from which to evaluate the economic impact of climate change by studying ECEs behind sectoral interactions. [ABSTRACT FROM AUTHOR]

Abstract: In order to analyze the dynamic evolutionary process of Chinese emerging housing market, the paper defines the behavioral functions of household agents in terms of demand generation, information search and price negotiation, and incorporates multi-agent technique and geographic information system to conduct a series of simulation studies on Beijing housing market. By setting different market scenarios, the impacts of new housing supply and information level on Beijing housing market are addressed. The findings show that, Beijing housing market is characterized by the prominent urban expansion with the formation of consolidated residential zones outside the 5th ring road; the growth in new housing supply can reduce the buyer search duration significantly, and lead the buyer search flow to the new housing market; higher information level can increase the sales of resale housing market, but inhibit the sales and time on market for new-built houses to some extent. [Copyright &y& Elsevier]

The coordination development among various subsystems, especially among economic, social and environmental subsystems, is an important part of urban sustainability that directly affects the quality of urbanization. This paper evaluated the sustainability of the 9 China's national central cities using the coupling coordination model. In the evaluation process, an objective coupling weighting method was developed by the combination of the coupling analysis and the sequential relationship analysis method. The validity of this method was illustrated by comparing the coordination level of the cities with that obtained by the entropy method. Long-term use of this method can guide the coordination development among economy, society and environment of cities. The assessment results indicate that the coordination development among economy, society and environment of the cities was not ideal. Only one city, Beijing, located in the good coordination grade. The main reason is the lower development of economic sustainability. Policy recommendations were provided to address the problem. In addition, the paper concludes that there is a great room for improvement in the coordinated development of the cities, because they showed an increase trend in coordinated development and the economic growth rate was relatively high. [ABSTRACT FROM AUTHOR]

Abstract: The identification of the relationships between different landscape services is important in social–ecological complex systems, especially in areas with intensive human activities. In this paper, Beijing and its peripheral regions are taken as a case study to calculate and map the intensities of five classic landscape services including material production, carbon storage, soil retention, habitat conservation, and population support based on grid maps. Overlap and correlation analyses were used to identify multiple service hotspots and the relationships between landscape services. The results show that (1) landscape services have spatial heterogeneity: high-intensity area of material production and population support is on the southeast plains of this region and high-intensity area of soil retention and habitat conservation is on the northwest; (2) approximately 96.03% of the region can provide at least one type of landscape services, whereas approximately three-quarters of the area provide multiple services, with the multiple service hotspots surrounding Beijing and Tianjin; (3) correlations exist between all pairs of landscape services, but strong correlations (correlation coefficient >0.5 or <−0.5) exist between four pairs, which are soil retention and habitat conservation (0.672), soil retention and population support (−0.613), habitat conservation and population support (−0.540), and material production and population support (0.529); (4) the services can be divided into two trade-off service bundles: the “natural” bundle, which contains carbon storage, soil retention, and habitat conservation, and the “artificial” bundle, which contains material production and population support. Only 4.19% of the area in this region contains these service bundles simultaneously. Finally, an improved understanding of the relationships between services was illustrated, and the importance of such services was highlighted for decision-makers and stakeholders. [Copyright &y& Elsevier]

Abstract: This paper aims to study the vehicular emissions trends in the Beijing–Tianjin–Hebei (BTH) region, located in northern China. The multiyear emission inventories of NO X , CO, VOC and PM10 from road vehicles in the period 1999–2010 were developed by the COPERT IV model. Results show that vehicular emissions of CO and VOC have decreased by annual average change rates (AACR) of −3.1% to −5.2% and −4.4% to −6.9% in the study area, respectively. However, due to the rapid development of freight traffic, emissions of NO X and PM10 have kept increasing in Tianjin and Hebei. Based on the vehicular emission inventories, trends of emission levels for vehicles with different standards, as well as the overall effects of implementing vehicular emission mitigation strategies were assessed. It is suggested that passenger cars (PC) with Euro 0 and Euro I standards, which were at higher emission level in the PC fleet, should be gradually eliminated. Although the increasing rates (IR) of emissions from PC were lower than those of the PC population, the sharp growth of PC population in recent years contributed to a remarkable increase of emissions, weakening the overall mitigation effect. Total vehicle population capacity and other mitigation measures should be studied in China in order to develop new and more effective vehicular emission control strategies. [Copyright &y& Elsevier]

Abstract: In order to further study the realization of carbon intensity target, find the key influencing factors of CO2 emissions, and explore the path of developing low-carbon economy, this paper empirically studied the influences of urbanization level, economic level, industry proportion, tertiary industry proportion, energy intensity and R&D output on CO2 emissions in Beijing using improved STIRPAT (stochastic impacts by regression on population, affluence and technology) model. The model is examined using partial least square regression. Results show that urbanization level, economic level and industry proportion positively influence the CO2 emissions, while tertiary industry proportion, energy intensity and R&D output negatively do. Urbanization level is the main driving factor of CO2 emissions, and tertiary industry proportion is the main inhibiting factor. In addition, along with the growth of per capita GDP, the increase of CO2 emissions does not follow the Environmental Kuznets Curve model. Based on these empirical findings and the specific circumstances of Beijing, we provide some policy recommendations on how to reduce carbon intensity. Beijing should pay more attention to tertiary industry and residential energy consumption for carbon emission reduction. It is necessary to establish a comprehensive evaluation index of social development. Investing more capital on carbon emission reduction science and technology, and promoting R&D output is also an efficient way to reduce CO2 emissions. [Copyright &y& Elsevier]

Abstract: External wall insulation plays an important role in building energy consumption through affecting cooling and heating energy uses. In this paper, a study on the effects of external wall insulation thickness on annual cooling and heating energy uses under different Chinese climates is reported. Firstly, two indexes: Energy Gain Ratio (EGR) and Relative Variation Ratio (RVR) of the sum of annual cooling and heating energy uses, to assess the effects of external wall insulation thickness on energy saving potential are introduced. Secondly, a model space having four different exterior zones facing four different orientations in an office building is presented and the settings of the model space described. Lastly, the simulated annual cooling and heating energy uses for the four different exterior zones at different external wall insulation thicknesses under three different climates in China, Guangzhou, Shanghai and Beijing, are reported. The results suggested that energy saving was significant by increasing the external wall insulation thickness in exterior zones facing all orientations under Beijing’s climate, since the heating energy use was dominant and can be reduced remarkably with the increase in insulation thickness. Under Shanghai’s climate, increasing external wall insulation thickness to over 26mm would not reduce the sum of annual heating and cooling energy uses in the south-facing exterior zone, but would help save energy in exterior zones facing the other three orientations. For all exterior zones under Guangzhou’s climate, it was, however, hardly possible to reduce the sum of annual heating and cooling energy uses by increasing the external wall insulation thickness. [Copyright &y& Elsevier]

Abstract: In recent years, wetland restoration measures have created extensive concerns globally. The theory and practice of restoring wetland vegetation diversity in wetlands through soil seed banks is discussed in this paper. A comparative study on soil seed bank and species composition in Yeyahu Wetland, Beijing, was conducted in 2007. Species and quantities of seeds from 12 sample sites were counted and measured by the seed-germinating method. After germination, 27 species belonging to 16 families and 23 genera were recorded, with an average of 11.75 species per sample site, and total average density of 24831.0individuals/m2. There were significant differences between the soil seed bank and vegetation in spring, summer and autumn, with similarity coefficients of 0.2620±0.0868, 0.2580±0.0778 and 0.1953±0.0452, respectively. Also in 2008, by using the seed bank technique, vegetation diversity was restored in a degraded wetland near Maying River of Yeyahu Wetland through the processes of spot selection, topographic surveying, water level monitoring, and vegetation management. The results showed that in the restored regions, both species and diversity coefficients of vegetation observably increased: 73.68% of the hydrophytic species we discovered were transplanted from provenance regions; germination of seeds in the soil lasted until late September; and many species completed their life history and produced new seeds to renew the seed bank. In addition, the results suggested that seed bank technique not only increased richness and multiplicity of vegetation, but also provided food chains with animal diversity in wetlands. [Copyright &y& Elsevier]

Abstract: To improve the air quality during the 2008 Beijing Olympic Games, the Beijing Municipal Government enforced a series of emission control measures. This provided a valuable case study to evaluate the effectiveness of these aggressive measures on mitigating air pollution and improving the atmospheric environment. In this paper, we report the first results of the chemical and Sr isotopic compositions of the rainwater in Beijing during the 2008 Olympic year. The ionic composition of samples show that Ca2+ and NH4 + were the dominant cations, accounting for about 76–97% of the total cations, and that SO4 2− and NO3 − were the major anions, accounting for 61–91% of the total anions measured. Using Na as the indicator of marine origin and Al as that of terrestrial inputs, the proportions of sea salt and terrestrial elements were estimated from elemental ratios. The calculated results indicate that the major chemical components were mainly of non-sea-salt origin. Good correlation between Ca2+ and Sr2+ (R 2 =0.85) in rainwater samples indicates the potential of Sr as a provenance tracer for Ca. Sr2+ concentrations in rainwater samples ranged from 0.01 to 2.87μmoll−1, with 87Sr/86Sr ratios from 0.7092 to 0.7109. All of the samples had a 87Sr/86Sr ratio higher than that of seawater. The 87Sr/86Sr isotopic and elemental ratio systems show that the data set of rainwater was mainly distributed between the seawater end-member (~0.70917) and the soil dust end-member (0.7111–0.7115), and the analysis indicate that the effect of anthropogenic inputs could decrease in 2008. Comparisons of the chemical composition of the rainwater in different periods show that all chemical components, except NH4 +, had the lowest concentration levels during the Olympic Game period. The VWM concentrations of major ions in the rainwater decreased significantly during the Olympic period by up to 29% for SO4 2−, 39% for NO3 −, 38% for Ca2+, 51% for Mg2+, 57% for K+, and 44% for Na+, compared with the pre-control period. The concentrations of almost all species decreased during the 2008 Olympics, most likely due to both strict emission controls and favorable meteorological conditions. [Copyright &y& Elsevier]

Abstract: A novel solar building cooling heating and power (BCHP) system driven by solar energy and natural gas is proposed in this paper. The performance of the presented system is greatly dependent upon the operation strategy. The primary energy consumption (PEC) and pollutant emissions of the solar BCHP system in following the electricity loads (FEL) and following the thermal loads (FTL) operation strategies are estimated based on life cycle assessment (LCA). Furthermore, three most important energy-related environment problems and human health issues, global warming, acid precipitation and respiratory effects, are considered to assess the environmental impacts of the system. In order to evaluate the comprehensive benefits achieved by the solar BCHP system in different operation modes, grey relation theory is employed to integrate the energetic benefits with environmental performances. Finally, a numerical case of the solar BCHP system for a commercial office building in Beijing, China is applied to compare the integrated performance in the FEL operation strategy with that of the FTL operation strategy. The results indicate that the energy saving and pollutant emissions reduction potentials of the FTL operation mode are the better than that of the FEL mode. [Copyright &y& Elsevier]

Abstract: This paper aims to discuss innovative plan models for Chinese cities that are currently under rapid development. The study considers Complexity Theories of Cities as the theoretical basis and applies a holistic approach in city planning by recognizing the complex nature of city. It strives to integrate the diverse local structure in social and spatial aspects with the ambition and demand of city''s expansion. Digital sequence simulation is used as an innovative tool to represent local activities, promote interventions and predict possible self-organization process in the future. The study arrives at an open scenario, the feasible prospect. A conclusion is drawn to reflect the process and achievement and propose future works for this research. [Copyright &y& Elsevier]

Abstract: Aerosol Robotic Network (AERONET) aerosol optical depth (AOD) and almucantar retrievals (single scattering albedo (SSA) and aerosol size distribution) from 2005–2009 in Beijing and Kanpur are used to analyze differences and similarities in aerosol optical properties over these two regions. The examination of monthly mean AOD (440 nm) shows that maximum and minimum values occurred in summer and winter, respectively, for Beijing, while the range in AOD in Kanpur was lower. Precipitation in both Beijing and Kanpur peaked in summer; however, the columnar water vapor (CWV) exhibited a high correlation with AOD in Beijing (R 2 = 0.79) but had a weak relationship with AOD in Kanpur (R 2 = 0.13). The Angstrom exponent (α, 440–870 nm) generally increased linearly as the fine mode fraction (FMF) of AOD (500 nm) increased for FMF < 90% in both regions, with a high correlation of R 2 > 0.96. However a clear decrease in α for FMF > 90% found in Beijing is not shown distinctly in Kanpur, and is mainly due to the higher aerosol loading in this FMF bin at Beijing (AOD at 440 nm > 2.2) which results in a stronger coagulation of fine mode particles. Bimodal seasonally-averaged size distributions reveals similar aerosol mixtures composed of fine pollution particles and coarse dust particles in both regions. The analysis of spectral SSA as a function of α is emphasized in this paper. The average SSA at 440 nm in both regions shows a similar low dynamic range of ∼0.03 for α < 1.4. The obvious increase in SSA at 440 nm for α > 1.4 in both regions can be attributed to a higher FMF leading to fine mode coagulation. However, the distinctly smaller increase in Kanpur suggests that fine mode aerosols at Beijing are less absorbing than those at Kanpur. The visibly lower SSA at 675 nm at Kanpur compared to that at Beijing for α > 0.4 is due to a larger find-coarse mode separation radius of ∼0.76 μm in Beijing versus a value lower than ∼0.58 μm in Kanpur. Another reason lies in the weaker absorption by fine mode aerosols in Beijing. The distinctly lower near-infrared SSA in Kanpur when α < 1.4, compared to Beijing, may be attributed to lower aerosol concentrations in all α bins, resulting in less aggregation of absorbing black carbon particles on coarse particles in Kanpur. The classification of aerosol properties shows that the AOD accumulation mode in all seasons, even including spring, in Beijing and in post-monsoon and winter seasons in Kanpur can be attributed to fine particle coagulation or hygroscopic growth; during pre-monsoon and monsoon seasons in Kanpur, it is due to coarse mode particle accumulation or cloud contamination. [Copyright &y& Elsevier]

Abstract: Operation mode of combined cooling heating and power (CCHP) system determines its energetic and environmental performances. This paper analyzes the energy flows of CCHP system and separated production (SP) system. The fuel energy consumptions of CCHP system following electrical demand management (EDM) and thermal demand management (TDM) are deduced respectively. Three indicators: primary energy saving, exergy efficiency and CO2 emission reduction, are employed to evaluate the performances of CCHP system for a commercial building in Beijing, China. The feasibility analysis shows that the performance of CCHP system is strictly dependent upon building energy demands. The selection of CCHP operation modes is systemically based on building loads, CCHP system and local SP system. The calculation results conclude that CCHP system in winter under EDM achieves more benefits than in summer. The sensitivity discussion indicates that the coefficient of performance for cooling and the efficiency of electricity generation are the most sensitive variables to the energetic and environmental performances of CCHP system. [Copyright &y& Elsevier]

Abstract: The use of groundwater for cooling and heating purposes is of interest from both the economical and the ecological perspective. The groundwater heat pump (GWHP) system utilizes groundwater as alternative renewable and clean energy source for space heating and/or cooling, withdraws water from a production well, passes it through a heat exchanger and discharges the water into an injection well. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance. Due to the utilization of groundwater stored in the aquifer, the assessment of the hydraulic capacity of the aquifer based on numerical groundwater models is always needed for the optimum design and the efficient performance of GWHP. In this paper, numerical methods of underground heat-water transfer, energy balance method and thermal storage method were presented to calculate the capacity of unit area of shallow groundwater aquifer. The model results indicate that the numerical method, which is based on performance efficiency of GWHP, represents the behaviour of groundwater pumping/recharging processes, and serves better than energy balance method and thermal storage method, in addition it has been proven itself that this method has the advantages of energy saving and environmental protection. The calculated capacity is positively related to aquifer thickness. It is found that it is easy for ground water recharge in alluvial and pluvial fan located at the piedmont, while the calculated capacity is relatively smaller compared with that of south-east plain where it is not easy for groundwater recharge. [Copyright &y& Elsevier]

Abstract: The concentrations, spatial distribution and compositional patterns of extensively used hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in urban dustfall in a metropolis-Beijing are presented in this paper. The potential sources are discussed and soil burdens are predicted based on the fluxes. The hotspots in commercial areas are identified by spatial distribution maps and the fractional value isomers indicates that dustfall in urban Beijing are affected by both current and historical usage of DDTs. It is worth noticing that there is possible application “dicofol-type of DDTs” in Beijing. The measured atmospheric deposition flux is 1.14×105 ngh−1 m−2 for HCHs and 1.47×105 ngh−1 m−2 for DDTs, respectively. However, when compared with atmospheric deposition flux, the volatilization flux estimated from concentrations in soils by fugacity model is significantly lower for HCHs (2.41ngh−1 m−2) and DDTs (0.07ngh−1 m−2). The net atmospheric flux to the soil suggests that the levels of HCHs and DDTs in soil are dominated by atmospheric deposition and the urban soil in Beijing would be a sink for HCHs and DDTs in the long term. [Copyright &y& Elsevier]

The minimum ecological water requirements of an urban river system and water deployment are key elements in integrated water resources planning and urban ecological construction. Based on a review of ecological water requirement calculation methods and considering the different ecological functions of an urban river system, the ecological function method was used in this paper to calculate the components of the ecological water requirements of an urban river. An envelope curve-based method was proposed for assessing the minimum ecological water requirements of an urban river system. Water resources deployment strategies designed to meet the minimum ecological water requirements were described. Then, the minimum ecological water requirements of the urban river system in Beijing central region, selected as a case study, were investigated. The key parameters for assessing the minimum ecological water requirement in the Beijing urban river system were determined. Based on the ecological objectives and the current status of the different urban river systems within the Beijing central region, the minimum ecological water requirements were calculated. Different types of water sources, including rainwater, upstream water, and reclaimed water, were deployed to meet the ecological water requirements for the urban river system in the Beijing central region. [Copyright &y& Elsevier]

Abstract: Beijing’s mountainous areas have an important ecological significance because they are ecological conservation and water source protection areas of Beijing. The impact of precipitation on the vegetation coverage of Beijing’s mountainous areas is qualitatively analyzed using multi-temporal Landsat images obtained during the last 20 years. Firstly, the influence of external factors, such as phenology and relative radiometric correction, on the normalized difference vegetation index (NDVI) are removed by the normalization of remote sensing images for different periods. Then, the vegetation coverage is calculated using the method of the dimidiate pixel model. Finally, based on that, the relationship between precipitation in different seasons and change of vegetation coverage is discussed. The results indicate that the mean vegetation coverage has the same change trends with winter and summer precipitation, but an opposite change trend with spring precipitation. The paper provides a theoretical basis and data support for further research on driving models of natural vegetation restoration in Beijing’s mountainous areas. [Copyright &y& Elsevier]

This paper presented a thermodynamic synthesis that involved resource accounting, evaluation and modeling of urban ecosystems based on embodied cosmic exergy (EcE), which redefined embodied exergy with the cosmic microwave background radiation (CMBR) as the reference for solar exergy. In a case study of the Beijing urban ecosystem, the major resources supporting the urban ecosystem, both from free natural resources and from the economy, were accounted for, analyzed and evaluated in the same units, Cosmic Joules (Jc). These indicators revealed the current performance of the Beijing urban ecosystem by considering five aspects of the system: EcE sources, EcE intensity, EcE welfare, environmental impacts and economic efficiency. Moreover, through the combination of the EcE synthesis with a systems dynamics, this research constructed an embodied cosmic exergy-based urban system model (EESM) using Beijing as an example of urban development. The results show that the 10 years from 2010 to 2020 will be very critical for the sustainable development of Beijing because many key factors, such as water resources, wastes and urban assets, might be confronted with great changes during this period. These changes will inevitably transform the urban system not only in its external circumstances but also in its inner structure and may lead to serious consequences. Of all the necessary resources, the most sensitive factor is water supply. [Copyright &y& Elsevier]

Abstract: This paper is to investigate the behavior of residents towards electrical and electronic waste (e-waste) recycling in Beijing. For this purpose a large sample questionnaire survey was performed to explore the residents’ characteristics of recycling behavior and preference of e-waste recycling pattern. Besides, the willingness of residents to participate in e-waste recycling was also assessed in our study. For this a logistic regression model was developed to estimate and explain residents’ willingness in e-waste recycling. The model showed that Convenience of recycling facilities and service, Residential conditions, Recycling habit and Economic benefits are four determinants of Beijing residents’ willingness and behavior in e-waste recycling. And centralized recycling pattern by professional recovery spots would have a broad prospect if various kinds of channels can be provided to make the residents feel more convenient in e-waste recycling. [Copyright &y& Elsevier]

Abstract: This paper deals with the limitations of visual interpretation of high-resolution remote sensing images and of automatic computer classification completely dependent on spectral data. A knowledge-rule method is proposed, based on spectral features, texture features obtained from the gray-level co-occurrence matrix, and shape features. QuickBird remote sensing data were used for an experimental study of land-use classification in the combination zone between urban and suburban areas in Beijing. The results show that the deficiencies of methods where only spectral data are used for classification can be eliminated, the problem of similar spectra in multispectral images can be effectively solved for the classification of ground objects, and relatively high classification accuracy can be reached. [ABSTRACT FROM AUTHOR]

Abstract: Presented in this paper is a low-carbon assessment for wastewater treatment by a constructed wetland as ecological engineering. Systems accounting by combining process and input–output analyses is applied to track both direct and indirect GHG emissions associated with the wastewater treatment. Based on the detailed assessment procedures and the embodied GHG emission intensity database for the Chinese economy in 2007, the GHG emissions embodied in both the construction and operation stages of a pilot constructed wetland in Beijing are investigated in concrete detail, with parallel calculations carried out for a cyclic activated sludge plant as a typical conventional wastewater treatment system for comparison. With the overall embodied GHG emissions taken into account, the constructed wetland is shown to be remarkably less carbon intensive than the conventional wastewater treatment system, and the contrast in GHG emission structure is also revealed and characterized. According to the results, the ecological engineering of the constructed wetland is considered to be favorable for achieving the low-carbon goal. [Copyright &y& Elsevier]

Abstract: An integrated wetland system (IWS) including constructed wetlands (CWs) and modified natural wetlands (NWs) for wastewater treatment to replenish water to wetlands located at the Beijing Wetland School (BWS) in Beijing, China, is presented in this paper. The synergistic effects of CWs and NWs on treated water quality are investigated. The IWS is proved to be an effective wastewater treatment technique and a better alternative to alleviate the water shortage for conservation of wetlands based on the monitoring data obtained from October 2007 to 2008. The results show that CWs and NWs play different roles in removing contaminants from wastewater. The COD removal efficiency in CWs is higher than that in modified NWs, whereas the modified NWs can compensate for the deficiency of CWs where a stable and sufficient rhizosphere is not fully formed in the start-up period. All removal rates of COD, TN, and TP in CWs and modified NWs vary from 50 to 70%, while the total removal rate of COD, TN, and TP in IWS is about 85–90%. The operational results show that the maximum area loading of organic pollutants in modified NWs (65kg/had) is slightly higher than the empirical one (60kg/had) recommended by for free water surface wetlands. [ABSTRACT FROM AUTHOR]

In this paper, emergy accounting (EA) and life cycle assessment (LCA) methods are employed to investigate a typical urban wetland park, the Green Lake Urban Wetland Park (GLUWP) of Beijing, in terms of its environmental and capital inputs, ecosystem services and organic matter yields, environmental support, and sustainability. The LCA method is also used to obtain a quantitative estimation of the environmental impact of discharges during the entire life cycle of the GLUWP. Various emergy-based indices, such as emergy yield ratio (EYR), environmental load ratio (ELR), emergy sustainability index (ESI), net economic benefit (Np), and environmental impacts of process-based LCA, including global warming potential (GWP), eutrophication (EU), nonrenewable resource depletion (RU), energy consumption (EN), acidification potential (AP), photochemical oxidant creation potential (POCP), particulate matter (PM) and wastes (W), are calculated. The results show that the GLUWP has higher proportions of renewable resource input, less pressure on the environment, more environmental support and better ecological and economic benefits, which can be considered as an environment-friendly and long-term sustainable ecological practice, compared with another constructed wetland in Beijing. Meanwhile, the dominant environmental impact is induced by POCP with the construction phase contributing the most on the entire life cycle. It is expected that increasing green area, extensively using environment-friendly materials, optimizing construction techniques and reducing power consumption can promote the sustainability of the GLUWP. [Copyright &y& Elsevier]

Abstract: This paper reports findings of a recent field study that characterized the on-road emissions of individual diesel vehicles in and around Beijing, China during November and December of 2009. We successfully sampled 230 individual trucks on 4 major expressways around the city as well as 57 individual buses in the city using refined mobile chasing techniques and fast response instruments. Emission factors (EF) for carbon monoxide (CO), black carbon (BC) and particulate matter with diameters less than 0.5 μm (PM0.5) are derived from the measurements, which are consistent with the results from laboratory dynamometer tests. The PM0.5 number emission factor distributions demonstrate consistent bimodal modes with peaks around 10 nm and 80 nm, while the mass emission factor distributions demonstrate a unimodal maximum around 110 nm for a majority of the trucks. The BC emissions are shown to be highly correlated with the mass emission of particles with 100–250 nm diameters, which are in good agreement with the results from previous studies. A number of important policy implications are discussed based on the results from this study. First, we identified “heavy emitters” in the on-road fleet we encountered, finding that 5% of diesel trucks in this sample are responsible for 50% of total BC emissions, and 20% of the trucks are responsible for 50% CO and PM0.5 number emissions, 60% PM0.5 mass emissions and over 70% of BC emissions. This suggests that emissions control programs should include identifying and removing heavy emitters from the road or improving their emissions. Second, the BC and PM0.5 number emission factors of trucks registered in regions outside Beijing are significantly higher than those of Beijing-registered trucks, suggesting that improving engine and fuel standards in Beijing alone is not sufficient in reducing the traffic-related air pollution in Beijing. Third, the significantly lower emissions from Euro IV and CNG buses compared to the Euro II and Euro III buses support that introducing clean-burning buses is an effective way to reduce the overall vehicle emissions for the pollutants studied. Fourth, our refined chasing method demonstrates a cost-effective approach to characterize the emissions from a large number of on-road diesel vehicles. Further studies with large sample sizes are critical to constructing more accurate mobile emission inventories to represent the on-road vehicle population. [Copyright &y& Elsevier]

Abstract: The first industrial-scale CO2 capture plant in China has been demonstrated at Huaneng Beijing power plant has shown that this technology is a good option for the capture of CO2 produced by commercial coal-fired power plants. The commissioning and industrial tests are introduced in this paper. The tests show that in the early stages of the passivation phase, the concentration variations of amine, anti-oxidant and Fe3+ are in the normal range, and the main parameters achieve the design value. The efficiency of the CO2 capture was about 80–85%, and by the end of January 2009 about 900tons of CO2 (99.7%) have been captured. The equipment investment and consumptive costs, including steam, power, solution and others, have been analyzed. The results show: the cost of the absorber and the stripper account for about 50% of main equipment; the consumptive cost is about 25.3US$ per metric tons of CO2, of which the steam requirement accounts for about 55%; the COE increased by 0.02US$/kWh and the electricity purchase price increased by 29%. [ABSTRACT FROM AUTHOR]