Search Results (4,436)

The EPA Positive Matrix Factorization (PMF) 5.0 model was applied to determine the sources and characteristics of PM₁₀ collected near the copper smelter in Bor, Serbia, from September 2009 to July 2010. For a better understanding of the industrial sources of PM₁₀ pollution, the dataset was divided into four observation periods: heating season (HS), non-heating season (NHS), copper smelter in work (SW), and copper smelter out of work (SOW). The daily limit for the PM₁₀ fraction of 50 μg/m³ was exceeded on one-sixth of days in the NHS, about half the days in the HS, and about one-third of days during the SOW and SW period. The nine different sources of PM₁₀ were identified: fuel combustion, industrial dust, dust from tailings, storage and preparation of raw materials, secondary nitrate, Cu smelter, traffic, cadmium, and plant for the production of precious metals. The contribution of factors related to the activities in the copper smelter complex to the total mass of PM₁₀ was 83.1%. When the copper smelter was out of work the contribution of all the factors related to PM₁₀ pollution from the copper smelter to the total mass of the PM₁₀ was 2.3-fold lower, 35.8%, compared with the period when the copper smelter was in work. This study is the first attempt to use PMF receptor modeling to determine the air pollution sources and their contribution to ambient air pollution in the city of Bor, Serbia. Full article

This paper proposes the PDDS model and constructs a three-dimensional analysis framework of policy objectives–policy tools–value chain in order to provide an in-depth analysis of 224 waste-free city policy texts released by China from 2019 to 2024. This study finds that China’s waste-free city policy objectives are macro-oriented, with specific objectives and milestones accounting for a relatively low proportion. Furthermore, there is a structural imbalance in policy tools, with environmental tools dominating and supply- and demand-based tools lagging behind. Additionally, support for each link in the value chain is uneven, with emphasis on the waste generation and disposal link, but the collection and regulation link is weak. In the three-dimensional analysis, China’s waste-free city policy exhibits a pattern of “overall goal leadership + environment-oriented policy tools + green industrial upgrading”. This study proposes a number of refinements to the policy objectives, improvements to the structure of policy instruments, enhanced synergies among the various segments of the value chain, and an increase in the aggregation effect of the policy objectives, instruments, and the evaluation chain. These changes are intended to promote the optimisation of waste-free city policies and the sustainable development of the environment in China and other countries. Full article

Accelerated urbanization and the excessive exploitation of the tourism industry are leading to a diminution of ecological spaces in tourist cities. Ecological networks are an effective method for improving patch connectivity and maximizing ecological space. However, previous research on ecological networks predominantly focuses on static snapshots, ignoring the fact that ecological networks are landscape entities with considerable spatiotemporal and structural dynamics changes. To fill this gap, we first constructed ecological networks of Guilin in 1990, 2000, 2010, and 2020, employing the integrated valuation of ecosystem services and tradeoffs (InVEST) model, the morphological spatial pattern analysis (MSPA) method, and circuit theory. Subsequently, we analyzed the spatiotemporal evolution of the ecological networks and proposed strategies for improving territorial space management. The results showed that ecological sources and corridors were generally decreasing in both number and areas (length), coupled with a notable increase in the number of ecological pinch points and barriers over the 30-year period. The spatiotemporal dynamics of ecological corridors, pinch points, and barriers were associated with ecological sources. Structural evaluation of the ecological networks revealed that during 1990~2020, the value of α (network closure) exceeded 0.7, the value of β (line point rate) surpassed 2, and the value of γ (network connectivity) was greater than 0.8, indicating robust overall connectivity within the ecological networks. The observed decline in these three indicators over time suggested a reduction in connectivity and the available dispersal pathways for species within the ecological networks, highlighting the need for protective measures and optimization strategies. Consequently, the ecological network conservation strategies and the development of ecological patterns were proposed to enhance ecological space management in Guilin. This study addresses a critical knowledge gap in the dynamics of ecological networks and offers valuable insights for mitigating habitat fragmentation and enhancing ecological space management of tourist cities. Full article

Exploring the ecological footprint and ecological carrying capacity is an effective method to evaluate the sustainable development and utilization of natural resources. Gansu Province, one of the typical arid regions in northwest China that is primarily focused on agriculture, was selected to analyze the evolution of the water ecological footprint and carrying capacity in this paper. In addition, the breadth and depth of the water footprint were combined to further evaluate the current situation of water resource utilization and management across different regions. This study can complement the research on the ecological footprint in arid areas dominated by agriculture. The results showed that (1) the agricultural water footprint was the main footprint and the key to water conservation. The overall water ecological footprint indicated a slow decline trend from 2009 to 2022 in Gansu Province. There was a gradual reduction in the agricultural water footprint and a notable increase in the ecological environment water footprint, indicating water use structures were generally becoming reasonable. (2) During the period, the eco-capacity and per capita eco-capacity exhibited similar trends in fluctuation and change, and spatial distribution was relatively dispersed due to the precipitation, total water resources, and industrial structure in the regions. (3) For prefecture-level cities, the depth of the water ecological footprint showed obvious spatial agglomeration. According to the results, the water footprint breadth of Zhangye and Longnan was larger, and the water resource flow can meet the local water demand. The water footprint depth of Lanzhou, Jinchang, Baiyin, and Jiayuguan was high, indicating the stock of water resources needs to be consumed to satisfy social production and living. The results can provide a scientific basis for the effective management and rational conservation of water resources. Full article

With rapid urbanization, intensified agricultural activities, and industrialization, groundwater resources are increasingly threatened by pollution. Industrial wastewater discharge and the extensive use of agricultural fertilizers in particular, have had substantial impacts on groundwater quality. This study examines 18 groundwater samples collected from the main urban area of Yibin City to assess hydrochemical characteristics, spatial distribution, source attribution, water quality, and human health risks. Statistical analysis reveals significant exceedances in TDS, NO₃⁻, Mn, and As levels in groundwater, with elevated concentrations of B as well. Isotopic analysis identifies atmospheric rainfall as the primary recharge source for groundwater in the area, with water–rock interactions and limestone dissolution playing key roles in shaping its chemical composition. Applying the Entropy-Weighted Water Quality Index (EWQI) for a comprehensive water quality assessment, the study found that 94.44% of groundwater samples were rated as “good”, indicating relatively high overall water quality. Deterministic health risk assessments indicate that 72.22% of the groundwater samples have non-carcinogenic health risks below the threshold of 1, while 66.67% have carcinogenic health risks below 1.00 × 10⁻⁴. Monte Carlo simulations produced similar results, reinforcing the reliability of the health risk assessment. Although the study area’s groundwater quality is generally good, a significant human health risk persists, underscoring the need to ensure the safety of drinking and household water for local residents. This study provides a valuable reference for the rational management and remediation of groundwater resources. Full article

With the rapid development of tourism, it has not only injected new vitality into Tibet’s economy but also had a profound impact on the lifestyle, cultural heritage, and social environment of its residents. While the prosperity of tourism brings economic opportunities, it also poses challenges to Tibet’s unique culture and ecological environment. In this research, we focus on Lhasa and Nyingchi as the study areas, analyzing the impact of tourism development on the economy, social culture, and environment from the perspective of the local residents’ perception and the residents’ willingness to participate in tourism. By constructing a structural equation model of local residents in Tibet with a total of 37 items in five dimensions, including economic perception, socio-cultural perception, environmental perception, tourism development attitude, and participation intention, perception characteristics were described based on a total of 677 questionnaires in Nyingchi City and Lhasa City. The economic, socio-cultural, and environmental dimension indicators were determined in positive and negative ways, and the characteristics and development trends of tourism in Tibet were discussed in depth. Positive economic, socio-cultural, environmental, and environmental perceptions display a significant positive correlation with tourism participation intention, and negative economic perception has a negative correlation with tourism participation intention. At the same time, we found that economic perception had the most significant impact on the residents in Tibet, and we put forward corresponding suggestions according to the current problems facing current tourism development. This study is of great value for the development of the tourism industry in Tibet. Full article

Using panel data of Chinese cities from 2006 to 2020, this study constructs the carbon emission performance index from the perspective of the dual differences in the four stages of growth, maturity, decline and regeneration of eastern, central, western and resource-based cities (RBCs). This study employs the Dagum Gini coefficient and kernel density estimation to explore σ convergence and β convergence for understanding the dual differences, dynamic evolutionary trend and convergence. Results indicate that during the sample period, the carbon emission performance index of RBCs shows a fluctuating upward trend with regional and typological imbalance influenced by geographical location and division of labour. The carbon emission performance index of RBCs of different regions and types (Growing, Mature, Declining and Regenerative) shows a fluctuating downward trend. However, the carbon emission performance index gap between the 116 RBCs in China is gradually expanding, further corroborating the influence of “excellent but outliers”. The overall level of carbon emission performance index of RBCs exhibits σ convergence, absolute β convergence and conditional β convergence phenomena. Notably, growing and regenerative RBCs demonstrate a clear “catching-up” trend compared to mature and declining RBCs. Furthermore, the inclusion of control variables reveals varying degrees of increased convergence speed. Environmental regulation intensity (ERI), gross domestic product (GDP), energy consumption structure (ECS), technology development level (T), industrial structure (IS) and foreign direct investment demonstrate significant regional and type heterogeneity in the changes in the carbon emission performance index of RBCs. Finally, based on the analysis results, implications are proposed to enhance the carbon emission performance of RBCs of different types, as well as at the national and regional levels. Full article

In recent years, the digital creative industry has manifested a vigorous growth trend along with the continuous upgrading of the Internet and the leap of the national economy. This research identifies the spatial distribution characteristics of digital creative enterprises in Shenzhen, employs big data of spatial information of various facilities such as transportation and commerce as the driving factor to construct a model, takes 1 km grid as the fundamental research unit, and explores the influence mechanism of enterprise location selection through methods like OLS and MGWR. The results are as follows: (1) The overall spatial distribution characteristics of digital creative industry are characterized by “widely distributed throughout the city, with a high concentration within the customs and a weak dispersion outside the customs”. (2) The factors of park foundation, production service, public service and life service exert a significant influence on the spatial distribution of digital creative industries in Shenzhen. Among them, the density of shopping facilities, staff, hotel and bus station exhibits a highly obvious spatial heterogeneity in terms of the influence on enterprise location. (3) The correlation of local scale factors is high and the influence range is precise, which frequently presents complex correlation outcomes in small scales such as streets or communities. Full article

The underdevelopment of tourism infrastructure remains a critical barrier to the growth of the tourism sector in both the capital and regional areas. This article examines the concept and structure of tourism infrastructure, synthesizes methodological approaches for its evaluation, and identifies the strengths and limitations of these approaches. The study introduces a novel methodology for assessing the development of tourism infrastructure in the capital city. Based on the assessment, the city’s regions are categorized into four levels of infrastructure development: high, above average, average, and below average. The findings highlight the key factors driving tourism development and the obstacles limiting infrastructure progress, while also proposing strategic directions for its enhancement. Achieving optimal levels of infrastructure provision is identified as a crucial condition for advancing the tourism sector. The development of tourism infrastructure should be prioritized in regional economic policy. In line with the state’s “Concept for the Development of the Tourism Industry of the Republic of Kazakhstan for 2023–2029”, this study emphasizes the need for a streamlined and precise classification of tourism infrastructure components based on a comprehensive framework. The evaluation is conducted using an integrated indicator that captures the development level of key elements: accommodation infrastructure, international event venues, and access to leisure and entertainment. Additionally, the article provides a comparative analysis of the current state of tourism infrastructure relative to the early stages of the capital’s development and tracks the dynamics of tourism indicators from 2010 to 2024. Several interrelated challenges affecting infrastructure growth have been identified. Notably, the study reveals that hosting international events and forums has significantly boosted inbound tourism compared to regional averages in Kazakhstan, although it has also constrained the potential for tourism business growth in other regions. The practical insights derived from this study offer a comprehensive understanding of the state of tourism infrastructure in Astana, which can inform future research and policy development for tourism infrastructure in major urban areas. Full article

Transboundary water pollution is a major global challenge as its movement and impacts remain unsurveyed. Monitoring pollution along international borders can reveal some of the pathways by which sewage and chemicals enter water bodies, and can hence advance the implementation of measures to prevent leakages and discharges into international waters. In this paper, we surveyed the impacts of sewage pollution and chemicals along the U.S.–Mexico international border, using Imperial Beach (California) as a main case study. Pollution was primarily attributed to the inflow of contaminated waters from the neighboring city of Tijuana (Mexico), where a malfunctioning wastewater treatment plant and a lack of sewage pipes being upgraded have caused direct leakage and toxic discharges into the Tijuana River. Reported effects from water pollution at the Tijuana River estuary in Imperial Beach include frequent beach closure, damages to coastal ecosystems, negative impacts on the fishery industry, and several effects on the health of beach users and surfers. Hence, the situation requires urgent measures oriented at coastal management at the mouth of the Tijuana River as well as the consistent monitoring and reporting of human health effects linked to beach uses. Full article

The aim of this study is to explore how marine ranching construction enhances the market-oriented potential for energy conservation and emission reduction in China’s coastal cities, and its motivation is to assess the role of marine ranching in promoting sustainable development and environmental protection in these urban areas. With a sample of 53 coastal cities, including experimental-group cities designated as national marine-ranching demonstration zones and a control group of other coastal cities, this research employs theoretical pathway analysis and a quasi-natural experiment design. The findings reveal that marine ranching notably improves both the green innovation capability and industrial upgrading in coastal cities, ultimately stimulating their market-oriented emission-reduction potential. Importantly, extreme weather conditions are found to disrupt the positive impact of marine ranching on the emission-reduction potential in coastal cities, while financial stability ensures its sustained beneficial effects. This study underscores the crucial role of marine ranching in promoting sustainable development and emission reduction in China’s coastal urban areas, emphasizing the importance of addressing climate challenges and maintaining financial stability. Full article

With the spread of the concept of sustainable development, the quality of development of the construction industry has begun to receive attention. Compared with speed, the quality of the development of the construction industry is not only reflected in its output, but also its impact on socio-economic development factors, which should be emphasized, and the comprehensiveness of its measurement is more difficult to ensure. However, theoretical and practical research on construction development in developing countries has been limited, mainly in terms of the semantic foundations and quantitative methods of the subject. Therefore, this paper focuses on China, the largest developing country, defines the concept and connotation of high-quality development of the construction industry (HQDCI), and constructs a set of tools for evaluating and analyzing HQDCI based on the theory of mutation and the relevant theories of spatial econometrics. In case studies, we also found that the key role of innovation drive and social contribution in HQDCI has been highlighted, and the balance of development has constrained HQDCI in some regions. In terms of spatial analysis, we find that the role of economic circles and city clusters in promoting HQDCI deserves attention, mainly because economic circles and city clusters can drive regional coordination, resource integration, and innovation diffusion. This paper expects to provide some insights into the transformation and sustainable development of other developing countries through this evaluation and analysis system based on the transformation of China’s construction industry. Full article

Atmospheric particulate pollution in China’s megacities has heightened public concern over air quality, highlighting the need for precise identification of urban pollution characteristics and pollutant transport mechanisms to enable effective control and mitigation. In this study, a new method combing the High Accuracy Surface Modeling (HASM) and Multiscale Geographically Weighted Regression (MGWR) was proposed to derive seasonal high spatial resolution PM_2.5 concentrations. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) was applied to analyze the seasonal spatial variations, transport pathways, and potential sources of PM_2.5 concentrations across China’s four megacities: Beijing, Shanghai, Xi’an, and Chengdu. The result indicates that: (1) the proposed method outperformed Kriging, inverse distance weighting (IDW), and HASM, with coefficient of determination values ranging from 0.91 to 0.94, and root mean square error values ranging from 1.98 to 2.43 µg/m³, respectively; (2) all cities show a similar seasonal pattern, with PM_2.5 concentrations highest in winter, followed by spring, autumn, and summer; Beijing has higher concentrations in the south, Shanghai and Xi’an in the west, and Chengdu in central urban areas, decreasing toward the rural area; (3) potential source contribution function and concentration weighted trajectory analysis indicate that Beijing’s main potential PM_2.5 sources are in Hebei Province (during winter, spring, and autumn), Shanghai’s are in the Yellow Sea and the East China Sea, Xi’an’s are in Southern Shaanxi Province, and Chengdu’s are in Northeastern and Southern Sichuan Province, with all cities experiencing higher impacts in winter; (4) there is a negative correlation between precipitation, air temperature, and seasonal PM_2.5 levels, with anthropogenic emissions sources such as industry combustion, power plants, residential combustion, and transportation significantly impact on seasonal PM_2.5 pollution. Full article

As a central subdivision of the low-altitude economy industry, industrial and consumer drones have broad market application prospects and are becoming the primary focus of the low-altitude economy; however, with increasing aircraft density, effective planning of reasonable flight paths and avoiding conflicts between flight paths have become critical issues in UAV clustering. Current UAV path planning often concentrates on 2D and 3D realistic scenes, which do not meet the actual requirements of realistic spherical paths. This paper has proposed a Gradient-Based Optimization algorithm based on the State Transition function (STGBO) to address the spherical path planning problem for UAV clusters. The state transition function is applied on the scale of medium and high-dimensional cities, balancing the stability and efficiency of the algorithm. Through evolution and comparisons with many mainstream meta-heuristic algorithms, STGBO has demonstrated superior performance and effectiveness in solving Medium-Altitude Unmanned Aerial Vehicle (MUAV) path planning problems on three-dimensional spherical surfaces, contributing to the development of the low-altitude economy. Full article

The Silway River has historically failed to meet safe fecal coliform levels due to improper waste disposal. The river mouth is located in General Santos City, the tuna capital of the Philippines and a leading producer of hogs, cattle, and poultry. The buildup of contaminants due to direct discharge of waste from chicken farms and existing water quality conditions has led to higher fecal matter in the Silway River. While there were technical reports in the early 2000s about poultry farming, this is the first study where fecal coliform from poultry farming was detected in the Silway River using highly sensitive protocols like qPCR. This study characterized the effect of flow velocity and physicochemical water quality parameters on chicken fecal contamination. Gene markers such as Ckmito and ND5-CD were used to detect and quantify poultry manure contamination through microbial source tracking (MST) and environmental DNA (eDNA) profiling. The results of this study showed the presence of chicken fecal bacteria in all stations along the Silway River. The results revealed that normal levels of water quality parameters such as temperature, pH, and high TSS concentrations create favorable conditions for chicken fecal coliforms to thrive. Multiple regression analysis showed that flow velocity and DO significantly affect chicken fecal contamination. A lower cycle threshold (Ct) value indicated higher concentration of the marker ND5-CD, which means higher fecal contamination. It was found that there was an inverse relationship between the Ct value and both velocity (R² = 0.55, p = 0.01) and DO (R² = 0.98, p = 0.2), suggesting that low flow velocity and low DO can lead to higher fecal contamination. Findings of fecal contamination could negatively impact water resources, the health of nearby residents, and surrounding farms and industries, as well as the health and growth of fish. Full article