Search Results (145)

The sustainable development of Chinese cities is of long-term significance. Multiple environmental regulatory instruments aim to promote the parallel advancement of environmental conservation and economic growth. This study examines three batches of low-carbon city pilot (LCCP) programs, employing eco-efficiency as the outcome variable. Using conventional difference-in-differences (DID) models, time-varying DID models, and period-by-period propensity score matching DID (PSM-DID) models with city and time fixed effects, we investigate the comprehensive impact of pilot policies on both economic and environmental performance. Eco-efficiency, measured through the Data Envelopment Analysis (DEA) model, exhibits a strong correlation with energy consumption patterns, as carbon emissions and air pollutants predominantly originate from non-clean energy utilization. The analysis reveals that LCCP policies significantly enhance eco-efficiency. These findings demonstrate robustness across placebo tests, endogeneity treatments, and alternative outcome variable specifications. The first and third LCCP batches significantly improve eco-efficiency, whereas the second batch demonstrates no statistically significant effect. Significant impacts emerge in regions where cities hold pilot status while provinces do not; conversely, regions where both cities and provinces participate in pilot programs show no significant effects. Finally, from an energy consumption perspective, policy recommendations are proposed to further enhance eco-efficiency through regulatory instruments. Full article

Responding to the challenges of global climate change and domestic air pollution, Taiwan revised its energy policy in recent years, introducing an energy transition strategy focused on low-carbon and clean energy. However, if photovoltaic installations are not properly sited, they may have negative impacts on the local environment. Previous research on renewable energy has primarily focused on policy evaluation, with limited attention given to case studies that examine the suitability of site selection for PV system installations. Thus, this study incorporates the Fuzzy Delphi Method (FDM) and the Analytic Hierarchy Process (AHP) to explore the criteria for evaluating site suitability for ground-mounted PV systems. This study considers existing sites with completed ground-mounted PV systems in Tainan City as case study subjects. The results indicate that the most important factor, as prioritized by experts, is the distance from Class I environmentally sensitive areas, followed by the duration of insolation, proximity to the electrical grid, and distance from residential areas. The evaluation model developed in this study provides a valuable reference for future site selection of ground-mounted PV systems. Establishing dedicated PV energy parks also may offer a viable solution to mitigate disputes related to the deployment of ground-mounted PV systems. Full article

This review thoroughly evaluates gasification as a transformative alternative to conventional methods for managing municipal solid waste (MSW), highlighting its potential to convert carbonaceous materials into syngas for energy and chemical synthesis. A comparative evaluation of more than 350 papers and documents demonstrated that gasification is superior to incineration and pyrolysis, resulting in lower harmful emissions and improved energy efficiency, which aligns with sustainability goals. Key operational findings indicate that adjusting the temperature to 800–900 °C leads to the consumption of CO₂ and the production of CO via the Boudouard reaction. Air gasification produces syngas yields of up to 76.99 wt% at 703 °C, while oxygen gasification demonstrates a carbon conversion efficiency of 80.2%. Steam and CO₂ gasification prove to be effective for producing H₂ and CO, respectively. Catalysts, especially nickel-based ones, are effective in reducing tar and enhancing syngas quality. Innovative approaches, such as co-gasification, plasma and solar-assisted gasification, chemical looping, and integration with carbon capture, artificial intelligence (AI), and the Internet of Things (IoT), show promise in improving process performance and reducing technical and economic hurdles. The review identifies research gaps in catalyst development, feedstock variability, and system integration, emphasizing the need for integrated research, policy, and investment to fully realize the potential of gasification in the clean energy transition and sustainable MSW management. Full article

Health hazards caused by indoor air pollution (IAP) remain a global concern, especially in developing countries. IAP has complex mechanisms related to outdoor air pollution (OAP) and various other factors, and their relationship needs to be clarified to examine effective policies. We conducted an indoor and outdoor air monitoring survey in urban, peri-urban, and rural areas in Bangladesh, one of the countries with the most severe air pollution. The results show that IAP is more severe in urban households than in rural households, with a five-fold difference in daily indoor ${\mathrm{P}\mathrm{M}}_{2.5}$ concentration between 117 $\mathsf{\mu }\mathrm{g}/{\mathrm{m}}^3$ and 22 $\mathsf{\mu }\mathrm{g}/{\mathrm{m}}^3$, respectively. Regression analysis reveals that IAP is strongly associated with OAP and is hardly affected by solid fuels used in well-ventilated outside kitchens. Our findings support the view that the mitigation of IAP in developing countries can be achieved not only through a transition to clean fuels, which often entails substantial costs, but also through more practical and accessible alternatives, such as the use of outdoor kitchens, electric fans, and careful management of behaviors such as indoor smoking and mosquito coil use. Full article

The global emphasis on clean energy has increased interest in producing hydrogen from petroleum reservoirs through in situ combustion-based processes. While field practices have demonstrated the feasibility of co-producing hydrogen and oil, the question of which offers greater economic potential, oil, or hydrogen, remains central to ongoing discussions, especially as researchers explore ways to produce hydrogen exclusively from petroleum reservoirs. This study presents the first integrated techno-economic model comparing oil and hydrogen production under varying injection strategies, using CMG STARS for reservoir simulations and GoldSim for economic modeling. Key technical factors, including injection compositions, well configurations, reservoir heterogeneity, and formation damage (issues not addressed in previous studies), were analyzed for their impact on hydrogen yield and profitability. The results indicate that CO₂-enriched injection strategies enhance hydrogen production but are economically constrained by the high costs of CO₂ procurement and recycling. In contrast, air injection, although less efficient in hydrogen yield, provides a more cost-effective alternative. Despite the technological promise of hydrogen, oil revenue remains the dominant economic driver, with hydrogen co-production facing significant economic challenges unless supported by policy incentives or advancements in gas lifting, separation, and storage technologies. This study highlights the economic trade-offs and strategic considerations crucial for integrating hydrogen production into conventional petroleum extraction, offering valuable insights for optimizing hydrogen co-production in the context of a sustainable energy transition. Additionally, while the present work focuses on oil reservoirs, future research should extend the approach to natural gas and gas condensate reservoirs, which may offer more favorable conditions for hydrogen generation. Full article

Understanding the economic value of natural resources is essential for the sustainable management of national parks. However, most existing studies focus on single conservation objectives and overlook the valuation of multiple resources within the same ecosystem. This study estimates tourists’ willingness to pay (WTP) for the conservation of four natural resources—crab-eating macaques, coral reefs, dry evergreen forests, and clean air—within Khao Laem Ya-Mu Ko Samet National Park in Thailand. Using the contingent valuation method and seemingly unrelated regression (SUR) analysis, data were collected from 205 tourists using structured surveys. The results show that dry evergreen forests received the highest average WTP (THB 129/year), followed by coral reefs (THB 125), clean air (THB 110), and crab-eating macaques (THB 107). At the population level, aggregate annual WTP values ranged from THB 85.7 million to THB 103.2 million across the resources. Age and awareness levels were consistent positive predictors of WTP, while other influencing factors—such as education, income, nationality, and residential location—varied by resource type. The findings provide empirical insights for designing resource-specific conservation strategies and highlight the potential of economic valuation to support sustainable financing mechanisms and policy development for protected area management. Full article

Poor air quality in India has sparked our interest in studying the time series dynamics of PM_2.5 in India’s five most populous cities (Mumbai, New Delhi, Hyderabad, Chennai, and Kolkata). Daily data for the period 2014–2023 are examined in the paper. Using fractional integration methods, we analyze the persistence, seasonality, and time trends of the data. The results indicate that all seriGewekees display fractional degrees of integration, being smaller than 1 and thus presenting mean reversion. Moreover, the time trends are significantly negative only for New Delhi and Kolkata, implying a continuous reduction in the level of pollution. These findings suggest that targeted interventions, such as stricter emission regulations, improved urban planning, and the promotion of clean technologies, are essential to sustain and amplify the observed improvements in air quality. The study also highlights the need for consistent and long-term efforts to address pollution in Mumbai, Hyderabad, and Chennai, where no significant reductions have been observed, emphasizing the importance of adapting policies to regional conditions. The paper’s findings can serve as a guide for air pollution management and for policymakers at the Central Pollution Control Board (CPCB), the governmental body responsible for monitoring and regulating environmental pollution in India. Full article

The aviation sector is a significant contributor to greenhouse gas emissions, and with the increasing demand for air travel these emissions are projected to continue rising in the coming years. Sustainable Aviation Fuel (SAF) could greatly help reduce these emissions and make the aviation industry more eco-friendly. SAF is a renewable, low-carbon alternative to conventional jet fuel produced from sustainable resources. A key step to bringing the fuel into regular use is studying how people view it. Understanding what the public think and feel about biofuels, including aviation fuel, is very important. This is because public opinion can shape consumer interest, demand for products, and the willingness of governments to back green energy policies and invest in clean technologies. The study systematically evaluates the public opinion, perception and awareness of SAF in the South Central United States and its utilization to decarbonize the aviation industry. This is performed through a series of multiple-choice survey questions and interviews. The study results show that while there is some recognition of the environmental impact of aviation and the potential role of biofuels in reducing this impact, there is still a need for greater public education and awareness regarding alternative fuels and their benefits for sustainable aviation. The findings of the study underscore a pivotal challenge in addressing aviation-related carbon emissions: the gap in public knowledge about potential solutions like biofuels and SAF. This gap not only reflects a lack of awareness but also hints at the possible skepticism or uncertainty among the public regarding the effectiveness and viability of these alternatives. Full article

The Fuzzy-Set Qualitative Comparative Analysis (fsQCA) method is employed in this study to investigate the combined effects of region area, the number of COVID-19 infections, and the number of family cars on NO₂ concentration at key highway toll stations in Zhejiang Province, China. By selecting and comparing typical cases, the analysis reveals differentiated characteristics in how various factor combinations influence NO₂ concentration. The main findings are as follows: Under COVID-19 lockdown measures, prolonged vehicle waiting times and a shift towards family car usage among the public have led to a significant increase in NO₂ concentration at highway toll stations. Promoting the Electronic Toll Collection (ETC) system and encouraging public transportation are of great importance. The synergistic effects of COVID-19 lockdown policies and urban land area, resulting in the reduction in the number of family cars and the excellent air circulation conditions in large cities, have contributed to the decrease in NO₂ concentration at highway toll stations. Increasing urban green spaces and promoting clean energy vehicles are crucial for advancing urban sustainable development. The combined analysis of the region area and the number of family cars indicates that a higher proportion of large vehicles contributes to improving transportation efficiency, but also results in elevated NO₂ concentration at highway toll stations due to diesel emissions. Optimizing the transportation structure and reducing reliance on large vehicles are of significant importance. Full article

Nickel, as a toxic trace element in fine particulate matter (PM_2.5), has detrimental effects on both air quality and human health. Based on measurements from 2020 to 2021 using a single-particle aerosol mass spectrometer (SPAMS), this study investigates the properties of nickel-containing particles (NCPs) in Guangzhou. The composition, sources, and temporal trends of NCPs were evaluated and the impact of the clean ship fuel policy introduced in 2020 was also examined. The key findings include: (1) Nickel particles account for 0.08% number fraction of PM_2.5, which is consistent with previously reported mass fraction in PM_2.5. (2) Three distinct types of NCPs were identified, including Ni-fresh, Ni-aged, and Ni-ash. Each type exhibits unique characteristics in size distribution, wind direction dependence, sources, and temporal variations. Ni-fresh particles originate from shipping emissions in the Huangpu Port area 2 km away and are the major contributors to fine nickel particles in the region. (3) Ni-aged and Ni-ash particles, which carry secondary components, tend to be larger (>500 nm) and are representative of regional or background nickel particles. (4) The implementation of the clean ship fuel policy has effectively reduced the number concentrations of NCPs and is beneficial to regional and local air quality. Full article

The main objective of the research presented in this article was to analyze the composition of exhaust gases from passenger cars undergoing periodic inspections and to determine the influence of vehicle age, mileage and the applicable EURO emission standard on the level of emissions of individual components of exhaust gases and thus on the environment. The research was carried out at the District Vehicle Inspection Station in Nowy Sącz, using methods for analyzing the composition of exhaust gases and smoke opacity. The results obtained make it possible to assess whether exhaust emission diagnostics can form the basis for the implementation of a sustainable road transport policy. The study showed that older vehicles emit higher concentrations of carbon monoxide (CO) and hydrocarbons (HC), and diesel cars manufactured before 2010 are characterized by increased smoke opacity. A reliable analysis of the emissions performance of vehicles on the road enables more effective measures to be taken to reduce emissions and improve air quality through regulation, the introduction of clean traffic zones and raising environmental awareness among drivers. This is especially important in regions with specific geographical conditions, such as the Nowy Sącz district, where the terrain—Nowy Sącz is located in a basin surrounded by mountain ranges—favors the accumulation of pollutants and hinders the natural air circulation, leading to the long-term persistence of smog. Full article

Hydrogen energy is essential in the transition to sustainable transportation planning, providing a clean and efficient alternative to traditional fossil fuels. As a versatile energy carrier, hydrogen facilitates the decarbonization of diverse transportation modes, including passenger vehicles, heavy-duty trucks, trains, and maritime vessels. To justify and clarify the role of hydrogen energy in sustainable transportation planning, this study conducts a comprehensive techno-economic and environmental assessment of hydrogen production in the USA, Europe, and China. Utilizing the Shlaer–Mellor method for policy modeling, the analysis highlights regional differences and offers actionable insights to inform strategic decisions and policy frameworks for advancing hydrogen adoption. Hydrogen production potential was assessed from solar and biomass resources, with results showing that solar-based hydrogen production is significantly more efficient, producing 704 tons/yr/km², compared to 5.7 tons/yr/km² from biomass. A Monte Carlo simulation was conducted to project emissions and market share for hydrogen and gasoline vehicles from 2024 to 2050. The results indicate that hydrogen vehicles could achieve near-zero emissions and capture approximately 30% of the market by 2050, while gasoline vehicles will decline to a 60% market share with higher emissions. Furthermore, hydrogen production using solar energy in the USA yields a per capita output of 330,513 kg/yr, compared to 6079 kg/yr from biomass. The study concludes that hydrogen, particularly from renewable sources, holds significant potential for reducing greenhouse gas emissions, with policy frameworks in the USA, Europe, and China focused on addressing energy dependence, air pollution, and technological development in the transportation sector. Full article

This paper aims to assess the temporal and spatial variability of particulate matter (PM) concentrations (PM_2.5 and PM₁₀) at several rural and urban monitoring sites located in Portugal between 2011 and 2022. The exceedances to European Union Directive limits and World Health Organization (WHO) air quality guidelines were also evaluated. Higher PM concentrations were observed mainly at urban sites (e.g., up to 156 exceedances of the WHO PM_2.5 guideline for daily average concentrations were recorded in a year), with the main contributions being from traffic emissions and industrial activities. On the other hand, the lower number of exceedances at rural sites can be attributed to long-range transport (e.g., Saharan dust) and wildfires. Temporal trends showed that PM_2.5 concentrations decreased by up to 0.6 µg/m³ per year, while PM₁₀ reductions reached 1.0 µg/m³ per year at certain sites, showing the effectiveness of air quality policies and clean technology advancements. Also, the number of exceedances of the air quality guideline of WHO for PM_2.5 at urban traffic sites like Entrecampos decreased from 140 in 2015 to 15 in 2022. Principal component analysis grouped the air monitoring sites based on PM variability. These findings provide a comprehensive understanding of the temporal variation of PM concentration, contributing to air quality management strategies and the design of mitigation measures. Full article

Over the past decade, China has enacted forward-looking environmental policies that have significantly reduced air pollution. However, while there appears to be a synergy between economic development and improvements in air quality, regional imbalances in development and disparities in health risks underscore systemic challenges in environmental governance. This study employed a population-weighted exposure index to evaluate disparities in PM_2.5 exposure and its temporal and spatial trends, considering multidimensional socio-economic factors such as education, age, gender, occupation, and urban/rural backgrounds across 32 provinces and regions in China. The findings reveal that despite a notable decline in overall PM_2.5 concentrations between 2013 and 2020, improvements in air quality are uneven across regions, with less developed areas bearing a disproportionate burden of emission reductions. Urban centers exhibit lower exposure levels due to resource and industrial advantages, whereas towns experience higher risks of air pollution. Socio-economic disparities are evident, with increased exposure observed in high-pollution industries and among groups with lower educational attainment. Women are more likely to be exposed than men, and both the elderly and children face higher risks. To address these challenges, policies should focus on the economic development of underdeveloped regions, balance environmental protection with growth, prioritize heavily polluted areas and vulnerable populations, and promote the adoption of clean energy to mitigate pollution inequality. Full article

Ship emissions significantly impact air quality, particularly in coastal and port regions, contributing to elevated concentrations of PM_2.5, and PM₁₀, with varying effects observed across different locations. This study investigates the effectiveness of emission control policies, inland and port-specific contributions to air pollution, and the health risks posed by particulate matter (PM). A regression discontinuity model at Ningbo Port revealed that ship activities show moderate PM_2.5 and PM₁₀ variations. In Busan Port, container ships accounted for the majority of emissions, with social costs from pollutants estimated at USD 31.55 million annually. Inland shipping near the Yangtze River demonstrated significant PM contributions, emphasizing regional impacts. Health risks from PM_2.5, a major global toxic pollutant, were highlighted, with links to respiratory, cardiovascular, and cognitive disorders. Advances in air purification technologies, including hybrid electrostatic filtration systems, have shown promising efficiency in removing submicron particles and toxic gases, reducing energy costs. In this paper, a random forest machine learning model developed to predict particulate concentrations post-cleaning demonstrated robust performance (MAE = 0.49 P/cm³, R² = 0.97). These findings underscore the critical need for stringent emission controls, innovative filtration systems, and comprehensive monitoring to mitigate the environmental and health impacts of ship emissions. Full article