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Solar photovoltaic-thermal hybrid with phase change material (PVT-PCM) emerges as an intelligent game changer to stimulate the clean, reliable, and affordable renewable energy technology. This PVT-PCM technology can be manipulated into generating both electricity and thermal energy that feature its practicality for residential and industrial applications. Hybridized of PCM into PVT design adds value to existing architecture with its capability to store excess heat that can be used during insufficient solar irradiation. Present work gives overview of the PVT-PCM system on technology innovation toward commercialization (viz, solar end game) subjected to bibliometric analysis, research and development evolution, and patent activity. A consolidation of these review articles was decluttered to focus on the performance and efficiency of PVT-PCM technology based on the fact that commercialization is ready once the technology is completed and qualified (at technology readiness level, TRL: 8). Economic review was conducted to understand the feasibility of the existing solar technologies and how it affects the PVT-PCM market price. Based on the contemporary findings, promising performance of PVT-PCM technology has underpinned its feasibility and technology readiness. China has predominant local and international framework and expected to be the PVT-PCM technology trendsetter in the next years through its strong international collaborative projects and pioneer in PVT-PCM patent filing. This present work underscores the solar end-game strategy and recommendation to create a path forward to achieve clean energy transition. Though, as to the date of submission of this article, no industry  has found to manufacture/sell this hybrid technology in the market., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This research focuses on a bibliometric analysis of research on aerosols' impact on the glaciers in the Himalayan glacier region published in journals from all subject categories based on the Science Citation Index Expanded, collected from the Web of Science and Scopus database between January 2002 and April 2022. The indexing phrases like "aerosol," "glacier," and "snow" are commonly used terms and have been utilized to collect the related publications for this investigation. The document selections were based on years of publication, authorship, the scientific output of authors, distribution of publication by country, categories of the subjects, and names of journals in which scholarly papers were published. The number of articles on aerosols accelerating the melting of glaciers shows a notable increase in recent years, along with more glacier melting results from countries involved in climate science research. People's Republic of China (382) was the country with the highest publication output on aerosols impacting the melting of glaciers. The USA (367) was the most cited country, with about 17,500 total citations and 80.40 average citations per year from January 2002 to April 2022. The results reveal that research trends in the glaciers on aerosols' impact on the glaciers have been attractive in recent years, and the number of articles in this field keeps increasing fast. This study offers opportunities to track research trends, identify collaboration prospects, and inform climate policy. Integrating data sources and engaging the public will further enhance the impact and relevance of this critical research field., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This paper presents the progress made by India and China in the field of waste management and its disposal since l996 to 2020. To access it, bibliometric analysis has been carried out using SCOPUS linked SCImago electronic database. Different bibliometric indicators such as documents, citable documents, external and self-citations, and external and self-citations per document along with their annual corresponding growth (ACG) have been calculated in order to explore the progresses made in both the countries. China has contributed 16.3% and India 4.3% to the total documents produced worldwide during 1996-2020 in waste management with the average ACG of 26.42% and 15.37%, respectively, during the same time span. Also, the average ACG for self-citations of published research documents is more than that of external citations for both the countries. In addition to that, the average self-citation magnitude reported for China (28,475) is more than that of India (5223), whereas this trend reverses in the case of average external citation per document with values 16.9 and 28.94, respectively. Moreover, the waste management practices being followed in both countries have also been compared and also presented so that it could be beneficial for the country which is relatively not good in the same., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aims to provide a comprehensive knowledge map of tourism and environmental degradation literature review based on scientific articles published between 1999 and 2020. The study provides an overview of research, influential authors, and journals. The PR China has maintained the lead in academic research with the most contribution in academic research in recent years. Sustainability, the Chinese Academy of Sciences, and Katircioglu are the most productive journal, academic institution, and author in the field of tourism and environmental degradation, respectively. The degree of research contribution among researchers, institutional and national level, has an upward trend in recent years, but the research contribution among author level is higher than the institutional and national level. Furthermore, co-citation analysis suggests that research articles in the field are closely related. "Investigating the influence of tourism on economic growth and carbon emissions: Evidence from panel analysis of the European Union" authored by Lee is the most cited article. Our analysis of abstracts and keywords shows that climate change, ecotourism, carbon emissions, economic growth, and energy consumption are the hot spots of academic literature. We suggest that research collaboration between developed and developing nations should be promoted in creating sustainable tourism reforms., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Green consumption (GC), as one of the important initiatives to achieve the goal of carbon peaking and carbon neutrality, has attracted widespread attention from scholars in environmental and economic fields. This article reviews the literature on GC, asking two main questions: how can GC research be analyzed from macro, meso, and micro perspectives? How have the research topics in the field of GC evolved in international and Chinese academia? This study makes a visual analysis of knowledge domain based on the literature of Web of Science Core Collection and China National Knowledge Infrastructure, so as to reveal hot topics, stage division, and research trend of GC research. The results revealed the following: GC research is in a period of rapid growth, and it is mainly distributed in developed countries dominated by the USA and in developing countries dominated by China. There is a trend of interdisciplinary research on GC, such as ecology, psychology, health, systematics, politics, and economics, which indicates that GC research has become increasingly inseparable from human survival and health, psychological acceptance, and social development. For the international academia, GC research pays more attention to the transformation of consumer psychology, while the Chinese academia is more concerned with the regulation of consumer behavior and the activation of green emotions. Considering the focus and characteristics of GC supervision, this study proposes GC 3.0 with a consumer-oriented and emphasizing green emotions and proposes future application scenarios from four aspects: government supervision, social self-regulation, enterprise demonstration, and personal self-monitoring., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

China has been the world's largest emitter of carbon dioxide since 2006. To achieve the goal of carbon neutrality by 2060, social scientists must become involved in China's deep decarbonization process. However, Chinese social scientists have given little attention to climate change in their bibliometric research. Based on the Chinese Social Sciences Citation Index journal catalog of the four essential social sciences, namely, management, economics, politics, and sociology, we used the China National Knowledge Infrastructure database to quantify the extent to which Chinese social scientists are concerned about climate change. The results showed that from 1978 to 2020, 1179 articles on climate change were published in management, economics, politics, and sociology journals, which represented only 26.8% of the 4397 articles published on pollution in the same journals. Politics journals published the most articles (38.76%), while sociology journals published the fewest (2.37%). Thus, Chinese social scientists rarely considered climate change, mainly because this topic remains controversial in some fields and because of the influence of international politics in addition to the promotion and incentive mechanisms for researchers. We analyzed the keywords and evolution of climate change research in the four social sciences and our results show that social scientists should give greater emphasis to climate change in their research., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Buildings account for nearly 2/5ths of global energy expenditure. Due to this figure, the 90s witnessed the rise of green buildings (GBs) that were designed with the purpose of lowering the demand for energy, water, and materials resources while enhancing environmental protection efforts and human well-being over time. This paper examines recent studies and technologies related to the design, construction, and overall operation of GBs and determines potential future research directions in this area of study. This global review of green building development in the last two decades is conducted through bibliometric analysis on the Web of Science, via the Science Citation Index and Social Sciences Citation Index databases. Publication performance, countries' characteristics, and identification of key areas of green building development and popular technologies were conducted via social network analysis, big data method, and S-curve predictions. A total of 5246 articles were evaluated on the basis of subject categories, journals' performance, general publication outputs, and other publication characteristics. Further analysis was made on dominant issues through keyword co-occurrence, green building technologies by patent analysis, and S-curve predictions. The USA, China, and the UK are ranked the top three countries where the majority of publications come from. Australia and China had the closest relationship in the global network cooperation. Global trends of the top 5 countries showed different country characteristics. China had a steady and consistent growth in green building publications each year. The total publications on different cities had a high correlation with cities' GDP by Baidu Search Index. Also, barriers and contradictions such as cost, occupant comfort, and energy consumption were discussed in developed and developing countries. Green buildings, sustainability, and energy efficiency were the top three hotspots identified through the whole research period by the cluster analysis. Additionally, green building energy technologies, including building structures, materials, and energy systems, were the most prevalent technologies of interest determined by the Derwent Innovations Index prediction analysis. This review reveals hotspots and emerging trends in green building research and development and suggests routes for future research. Bibliometric analysis, combined with other useful tools, can quantitatively measure research activities from the past and present, thus bridging the historical gap and predicting the future of green building development., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Research on environmental footprint family (EFF), including these studies of environmental footprints and footprint family, has been widely applied to environmental impact assessment and sustainability evaluation. Although some bibliometric studies have focused on footprint indicators, there is still the lack of the contrast of Chinese and foreign literature in the field of EFF and the conclusions of successful practices at home and abroad in recent years. Unlike most previous papers, we improve the search strategy for collecting accurate documents data and compare China and foreign from a unified international perspective. Two datasets covering 1103 Chinese and 6011 foreign articles between 1996 and 2019 were collected to compare their bibliometric differences in EFF research. We not only comparatively investigate the overview of Chinese and foreign articles in EFF field based on the objects of publications, journals, authors, and institutions, but also explore their differences in the conceptual and intellectual structure from the aspects of keywords and citation analysis. For example, we can deduce that Chinese articles tend to engage in applied research and lack of theoretical innovations and breakthroughs in this field. Our comparative research results are useful and helpful for the public, policymakers, and researchers in this filed.

This study aims to provide a systematic literature review based on bibliometric analysis for scientific articles published between 1999 and 2019 extracted from Clarivate Analytics' Web of Science (WOS) database. The current research project provides an overview of scientific publications, influential authors, and research journals. Our analysis reveals that the USA leads the academic research contribution, whereas China has provided the most research publications in recent years. Environmental and Resource Economics, University of London, and Barcena-Ruiz are the most productive journal, academic institution, and author in the field of environmental taxes, respectively. The degree of research contribution among researchers, institutional and national level, has an upward trend in recent years; however, the research contribution at the author level is higher than the institutional and national level. Furthermore, cocitation analysis suggests that research articles in the dataset are closely related. Pigou's "The economics of welfare" published in 1920, is considered as the basic literature, and the "In defence of degrowth" authored by Giorgis Kallis is the most cited article. Our analysis of abstracts and keywords indicates that climate change, environmental taxes, double dividend, carbon tax, and environmental pollution are the hotspots within academic literature. We suggest that research collaboration between developed and developing nations and further coordination among environmental agencies such as IEA and IPCC will enhance the effectiveness of environmental reforms.

Green supply chain (GSC), one of the most vital sub-topics of sustainable development, indicates people provoking on the rationality of business practices and resource consumption patterns. Under the background of economy globalization, developing countries, especially China, severely affected by green barriers became the global focus. A systematic review of articles about GSC which published in leading journals of Web of Science Core Collection (WoSCC) and China Knowledge Resource Infrastructure (CNKI) is proposed for exploring publishing trends, the distribution of authors and journals, research topics, and hotspots and predicting frontiers by utilizing VOSviewer, Sci2, and CiteSpace. The results show that (1) there are differences in the attention of GSC between international and Chinese academia. (2) "Green" is referred to environmental friendly practices in international academia. Scholars advocate to promote management to strengthen cooperation among GSC members and boost technology investment to improve the comprehensive performance; however, specific practices such as "low-carbon," "emission reduction," "recycling," and "remanufacture" are referred to environmental friendly behaviors in Chinese academia. Scholars expect to avoid enterprises' short-term profit compression relying on government subsidies and make contracts to share environment protection cost equally out for ensuring GSC stable operation. (3) Exploring collaboration among GSC members using complex operation research and artificial intelligence will be international research frontier. Relevant papers are to provide Chinese research with merely innovation in methodology. Besides, the "government-enterprise-university-research institute-customer-economy" management mode proposed by development countries like China will enrich the international GSC research scope, leading international GSC knowledge structure to change. The contribution of this study is to afford reference for future research on GSC.

The pollution caused by modernization and industrialization has caused serious harm to the biodiversity of the earth. TiO 2 -based photocatalyst has been widely studied as an effective and sustainable water environment remediation material. In this study, we analyzed the status and research trends of TiO 2 -based photocatalytic degradation of wastewater in depression from 2003 to 2023 to provide a reference for further research. "Doping", "Modification" and "Heterojunction" were used as keywords, and 817 related academic literatures were screened out by using Web of Science database. Through the visualization software VOSviewer and CiteSpace, the authors, institutions and literature keywords were clustered. The results show that since 2008, the annual number of published papers on TiO 2 -based photocatalytic degradation of wastewater has increased from 9 to 114. Among them, China has published 432 articles and made great contributions, and there are many representative research teams. Chinese universities are the main body to study TiO 2 -based photocatalytic degradation of wastewater, but the cooperation between universities is not as close as that abroad. This paper comprehensively analyzes the research hotspots of TiO 2 -based photocatalytic degradation of wastewater, such as the doping of TiO 2 and the construction of different types of heterojunctions of TiO 2 . It is expected that these analysis results will provide new research ideas for researchers to carry out future research on related topics and let researchers know in-depth research institutions and possible collaborators to conduct academic exchanges and discussions with active institutions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Carbon dioxide capture, utilization, and storage (CCUS) technology is an emerging technology with large-scale emission reduction potential and an essential component of the global response to climate change to achieve net-zero goals. As the two most important countries in global climate governance, it is necessary to review and examine the current status and trends of research in the field of CCUS in China and the USA. This paper uses bibliometric tools to review and analyze peer-reviewed articles in the Web of Science from both countries during 2000-2022. The results show a significant increase in research interest among scholars from both countries. The number of publications in the CCUS field in China and the USA was 1196 and 1302, respectively, showing an increasing trend. China and the USA have become the most influential countries in CCUS. And the USA has a more significant academic influence on a global scale. Furthermore, the research hotspots in the field of CCUS are diverse and differentiated. That is, China and the USA pay attention to different research hotspots or have different focuses in different periods. This paper also finds that new capture materials and technology development, geological storage monitoring and early warning, CO 2 utilization and new energy development, sustainable business models, incentive policies and measures, and public awareness are critical directions for future research in the field of CCUS, to provide a comprehensive review and comparison of CCUS technology development in China and the USA. It helps to gain insight into the research differences and linkages between the two countries in the field of CCUS and identify the research gaps between them. And place some consensus that policymakers can use., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In recent years, there has been a rapid increase in scientific research into hydrogeochemical research on glacier meltwater. Nevertheless, systematic and quantitative analyses are lacking to investigate how this research field has developed over the years. As a result, this study is aimed at examining and evaluating recent research trends and frontiers in hydrogeochemical research on glacier meltwater throughout the previous 20 years (2002-2022) and at locating collaboration networks. This is the first global-scale study, and visualization of the key hotspots and trends in hydrogeochemical research has been presented here. The Web of Science Core Collection (WoSCC) database aided in the retrieval of research publications related to hydrogeochemical research of glacier meltwater published between 2002 and 2022. From the beginning of 2002 till July 2022, 6035 publications on the hydrogeochemical study of glacier meltwater were compiled. The result revealed that the number of published papers on the hydrogeochemical study of glacier meltwater at higher altitudes had grown exponentially, with USA and China being the main research countries. The number of publications produced from the USA and China accounts for about half (50%) of all publications from the top 10 countries. Kang SC, Schwikowski M, and Tranter M are highly influential authors in hydrogeochemical research of glacier meltwater. However, the research from developed nations, particularly the United States, emphasizes hydrogeochemical research more than those from developing countries. In addition, the research on glacier meltwater's role in streamflow components is limited, particularly in the high-altitude regions and needs to be enhanced., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Ecological restoration projects are becoming a mainstream of research, and their studies are widely followed by scholars worldwide, yet there is no comprehensive review of this research. Nowadays, bibliometrics has attracted much attention from the scientific community, and its methodological approach allows quantitative and qualitative analysis of research performance in journals or subject areas. This paper provides a systematic and comprehensive description of the progress and hotspots of ecological restoration projects from a bibliometric perspective, based on 1173 articles in the Web of Science Core Collection (WOSCC) database. Research on ecological restoration projects has shown a positive growth trend since the twenty-first century. China and the USA are the most active countries in terms of the number of relevant articles published, and more than half of the top 10 active institutions are from China, but there is less collaboration between different countries/institutions. Research in ecological restoration projects is summarized into three main research areas: the main ecological damage problems, the impact of human beings on ecological damage, and the main methods of ecological restoration. Finally, some challenges and outlooks conducive to the rapid and balanced development of ecological restoration projects are presented, which provide valuable references and help for future researchers., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Power sector carbon emissions (PSCEs) have received an increasing attention due to their huge contribution to global greenhouse gas emissions. Herein, the research characteristics and trends of PSCEs are investigated based on bibliometric analysis. The basic growth trends, contributions of the most productive countries/territories, institutions, authors, journals, and subject categories are analyzed systematically. In addition, the major research fields and research trends are investigated by the keywords co-occurrence analysis and topic evolution. The result indicates that PSCEs research has developed rapidly in the past 20 years, and the proportion of research funding has increased from 0 at the beginning to 73% in the last 5 years. Especially, the number of scientific publications has shown an explosive growth after the signing of the Paris Agreement in 2016. The People's Republic of China (PR China), the USA, and England are the three most dynamic countries in the field of PSCEs research, with 64.8% of the total number of published papers. The most productive institutions are also from these countries. Based on keywords co-occurrence analysis, it is concluded that driving factors, prediction, impacts, and countermeasures of carbon emission are three major research fields. The result of thematic evolution indicates that the topics on energy transition, life cycle assessment, marginal abatement cost and energy policy have been the research hotspots in recent years. This study presents an worldwide overview of PSCEs research, thus helping the stakeholders to quickly grasp the research trends and conduct future work., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study investigated the research trends, key areas, and directions of water rights (WRs) using bibliometric data based on the Science Citation Index Expanded (SCI-E) and Social Sciences Citation Index (SSCI). This paper presents a comprehensive review of annual output, research fields, cooperative networks, published journals, and hot spot evolution from 1971 to 2020. The results show that the number of published papers on WRs has an exponential upward trend. This research mainly focuses on water resources, environmental sciences, environmental studies, law, agronomy, and political science. Rutgerd Boelens and Barbara Van Koppen are authors of the most widely published and influential factors in the field. Leo Heller, Priscila Neves-Silva, and Jeroen Vos have been the most recently active authors. University of New Mexico and the United States Department of Agriculture are the organizations with the most publications and total citations, respectively. The USA, China, Australia, the UK, The Netherlands, and Spain are among the most productive countries for WR research. Keyword analysis showed that the study of WRs has gone through three stages: the exploration of laws and regulations, comprehensive management, and technology development and application. Literature citation cluster analysis shows that a highly central article provides a strong link between internal research on WRs. Western USA, trading WRs, and constitutional reform were hot spots before 2010, while economic anthropology, combined effect, public attitude, and integrated assessment modeling have become popular recently. The study results can help experts understand the research progress in WRs., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This paper aims to conduct a systematic overview of green growth literature and reveal the evolution, hot topics, as well as future directions of this field. Given the dispersion of the existing related studies, the development and evolution process of green growth have yet to be comprehensively reviewed. The qualitative review cannot objectively and quantitatively screen out important keywords, possibly leading to bias. This study uses a hybrid method based on bibliometric analysis and the fuzzy Delphi method to review 806 papers from the Scopus database. The findings show that there is an exponential rise in publications with the leading authors, countries, and institutions concentrated in South Korea, China, and the USA. The contents of core literature are focused on pathways and influencing factors of green growth. Hot topics, including policy support, resource management, emission reduction, and the application of new technology, are summarized. The top 5 keywords for future directions are energy, economy, emission, development, and management. The findings offer some valuable contributions to both academic and practical investigations of green growth., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Researchers have broadly studied textile waste, but the research topics development and performance trends in this study area are still unclear. A bibliometric analysis was conducted to explore the global scientific literature to determine state of the art on textile waste over the past 16 years. Data of publications output are identified based on the Web of Science (from 2015 to 2020). This study used VOSviewer to analyse collaboration networks among authors, countries, institutions, and author's keywords in identifying five main clusters. A total of 3296 papers in textile waste research were identified. In this study, a total of 10451 authors were involved in textile waste research, and 36 authors among them published more than ten research publications in the period of this study. China has been in a top position in textile waste research moving from 3 output publications in 2005 to 91 output publications in 2020. Indian Institute of Technology System IIT System was ranked first in terms of the total publication number (85 publications, 2.45%). Textile wastewater and adsorption are the most commonly used keywords that reflect the current main research direction in this field and received more attention in recent years. Based on keyword cluster analysis outputs, textile waste research can be categorized into five types of clusters, namely (1) pollutant compositions, (2) component of textile wastewater, (3) treatment methods for textile wastewater, (4) effect mechanism of textile wastewater, and (5) recyclability of textile waste., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Using the extended science citation index database (SCI) and social science citation index (SSCI) databases, this paper analyzed the characteristics of publications, research foundations, research hotspots, and the evolutionary tracks of studies in the field of energy, environment, and climate change from 1990 to 2019 using a bibliometric method. This method is useful because it involves the quantitative analysis of large amounts of literature, using mathematical and statistical method. The results showed that the United States (US), the United Kingdom (UK), and China were the countries with the most published papers in the field. The US plays a key role in the cooperation between international institutions. An assessment conducted by the Intergovernmental Panel on Climate Change (IPCC) created the standard scientific reference for the research on climate change and its consequences. From 2006 to 2016, a large number of co-cited papers laid a solid foundation for research in the field. During this period, the research focused on the impact of climate change on the ecological environment, began to propose different countermeasures, and formed a set of mature research methods. From 2017 to 2019, there was an acceleration in the growth rate of the number of published articles. Strategies to address climate change, including renewable energy and energy transition, were the focus during this phase. Future studies are expected to focus on climate change mitigation strategies and energy policies. The findings provide a reference for researchers and can help policy makers balance economic development with environmental protection., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Waste classification is to reduce solid waste and its associated environmental pollution. This paper applied bibliometrics to assess publications related to classification technology of domestic waste from 2000 to 2019. A total of 466 publications were retrieved. The results showed the number of citations and papers increased rapidly. The major publication type regarding waste classification technology is article and English is the primary language for academic communication. The research is multidisciplinary and interdisciplinary, and its research directions are mainly divided into "Engineering," "Environmental Sciences Economics," and "Chemistry." It was identified that Waste Management (85) published most of papers in this topic. Meanwhile, China (93) contributed the most of publications, followed by the USA (42), France (40), Japan (36), and Italy (28). European countries are in the leading position in the study of garbage classification technology. Plastics and waste metals were the existing focus of waste classification technology, and waste identification and classification has become an important classification method. In addition, we also summarized the current mainstream technology progress and possible research challenges.

The booming construction industry has led to many environmental and occupational health and safety problems. Construction dust caused irreversible damage to the health of frontline workers and polluted the surrounding air environment, which has attracted the attention of researchers and practitioners. In this study, to systematically sort and analyze the distribution of construction dust (CD) research, its hot areas, and the evolution of its fronts, papers with "construction dust" as the subject term in the Web of Science Core Collection Database since 2010 are visually analyzed using CiteSpace. The characteristics of these papers, including the quantity trend, quality, author group, affiliated institution type, and journal type, are summarized, and keyword co-appearance and paper co-citation knowledge maps are produced. The results show that (1) China is the backbone of CD research, and the research results account for a considerable proportion of the total. (2) Respiratory dust and atmospheric aerosols, marble dust, PM 2.5 , and other hot issues have always attracted international attention. And exposure assessment and spatial distribution were the main focuses in the study of CD. (3) The direction of CD research will explore in a more subtle and intelligent direction in the future, for example, monitoring and control equipment under the technical support of big data technology and machine learning and face recognition. By combining bibliometrics with a systematic review, we aim to analyze the research foci and future development direction deeply, providing scholars with a comprehensive view of the field.

Due to the environmental impact associated with the products' use, sustainable design has extended consideration of products' production to consumption. This study puts forward the concept of sustainable design for users (SDfUs). Using related keywords of sustainable design and user-centered design, we identify a total of 447 usable articles published during 1992-2019 from Scopus. Results of bibliometric analysis show that the number of SDfUs articles has generally continuously increased since 2007. The most productive scholars are from the USA, the UK, and China, while the top three organizations are Loughborough University, Norwegian University of Science and Technology, and Delft University of Technology. Different focuses of SDfUs appear among developed and developing countries. Green building design has emerged as one key area that uses the concept of SDfUs in developed countries such as the USA and the UK. SDfUs studies in developing countries such as China focus on design for end-of-life products' treatment and disposal. Most SDfUs studies examine how design can contribute to environmental performance through emission reduction and energy saving during products' use, and articles in one of five clusters from co-word analysis explore users' behaviors for sustainable design in the textile industry. This paper is the first study that systematically reviews the literature on SDfUs. It provides valuable insights for scholars in the SDfUs-related fields to identify their research directions and partners. Results on clusters from network analysis also offer practical implications for enterprises to learn from the construction and textile industries.

In recent years, climate change and carbon sinks have been widely studied by the academic community, and relevant research results have emerged in abundance. In this paper, a scientometric analysis of 747 academic works published between 1991 and 2018 related to climate change and carbon sinks is presented to characterize the intellectual landscape by identifying and revealing the basic characteristics, research power, intellectual base, research topic evolution, and research hotspots in this field. The results show that ① the number of publications in this field has increased rapidly and the field has become increasingly interdisciplinary; ② the most productive authors and institutions in this subject area are in the USA, China, Canada, Australia, and European countries, and the cooperation between these researchers is closer than other researchers in the field; ③ 11 of the 747 papers analyzed in this study have played a key role in the evolution of the field; and ④ in this paper, we divide research hotspots into three decade-long phases (1991-1999, 2000-2010, and 2011-present). Drought problems have attracted more and more attention from scholars. In the end, given the current trend of the studies, we conclude a list of research potentials of climate change and carbon sinks in the future. This paper presents an in-depth analysis of climate change and carbon sink research to better understand the global trends and directions that have emerged in this field over the past 28 years, which can also provide reference for future research in this field.

Biochar has been paid great attentions during the last two decades, because of its resources potentials and environmental benefits. A bibliometric analysis was applied to assess the publications regarding the keyword biochar from the Web of Science database during the period of 1999 to 2018. A total of 8629 publications were obtained with a rapid increase of annual citations and number of papers. The research topics were diversified, which were mainly divided into "Environmental Sciences and Ecology," "Agriculture," and "Engineering." Bioresource Technology was the journal which published most of the relevant papers. China ranked first in the number of published papers, followed by the USA, Australia, UK, and Germany. Especially, China established close collaboration with the USA in joint publication. Analysis of the keywords indicated that biochar production, comparative sorption, soil-applied black carbon, and soil management were the main research hotspots of biochar. The burst detection reflected that the innovation of biochar production and the new application field of biochar was the future research trends. These results can provide insight into the research progress regarding biochar.

Waste electrical and electronic equipment (WEEE) contains both toxic and valuable materials. Due to rapid development of information and communication technologies (ICT), a large amount of WEEE have been produced, leading to increasing academic efforts in this field. This study aims to depict the trends and features of WEEE-related studies through a bibliometric analysis. The results show that the total number of WEEE-related publications had sharply increased, with China as the leading country. University of Chinese Academy of Sciences is the most productive WEEE-related research institution, while Mai BX is the most productive author. As such, Waste Management, Journal of Cleaner Production, and Environmental Science & Technology are the most influential journals. The research hotspots of WEEE mainly focus on the recycling and treatment technologies, environmental impacts, and relevant policies of WEEE. By tracing the evolutionary pathway of WEEE research, it is clear that the research frontiers have switched from electronic equipment, extended producer responsibility, sediment, environment and design, risk assessment to life cycle assessment, mobile phone, and behaviors. This study provides valuable insights to those WEEE-related scholars so that they can identify their own research topics and partners. This paper is one of the first studies in WEEE research field that offers critical discussions and suggestions related to research development and future trends, and used visualized tools to present the holistic picture of this field.