Environmental Science and Pollution Research https://doi.org/10.1007/s11356-023-27699-3 REVIEW ARTICLE A bibliometric analysis of the impact of COVID‑19 social lockdowns on air quality: research trends and future directions Emmanuel Mensah Aboagye1  · Nana Adwoa Anokye Effah2 · Kwaku Obeng Effah1,3 Received: 26 October 2022 / Accepted: 12 May 2023 © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023 Abstract Social lockdowns improved air quality during the COVID-19 pandemic. Governments had previously spent a lot of money addressing air pollution without success. This bibliometric study measured the influence of COVID-19 social lockdowns on air pollution, identified emerging issues, and discussed future perspectives. The researchers examined the contributions of countries, authors, and most productive journals to COVID-19 and air pollution research from January 1, 2020, to September 12, 2022, from the Web of Sciences Core Collection (WoS). The results showed that (a) publications on the COVID-19 pan- demic and air pollution were 504 (research articles) with 7495 citations, (b) China ranked first in the number of publications (n = 151; 29.96% of the global output) and was the main country in international cooperation network, followed by India (n = 101; 20.04% of the total articles) and the USA (n = 41; 8.13% of the global output). Air pollution plagues China, India, and the USA, calling for many studies. After a high spike in 2020, research published in 2021 declined in 2022. The author’s keywords have focused on “COVID-19,” “air pollution,” “lockdown,” and “PM25.” These keywords suggest that research in this area is focused on understanding the health impacts of air pollution, developing policies to address air pollution, and improving air quality monitoring. The COVID-19 social lockdown served as a specified procedure to reduce air pollution in these countries. However, this paper provides practical recommendations for future research and a model for environmental and health scientists to examine the likely impact of COVID-19 social lockdowns on urban air pollution. Keywords COVID-19 · Social lockdowns · Air pollution · Bibliometric analysis · Citation analysis Introduction for “Virus,” and D stands for “Disease” (Chakraborty and Maity 2020). World history documents several pandemics On December 31, 2019, the world experienced a novel virus that have hit the world, like the plague, smallpox, measles, that caused animals and humans to be sick. Shortly after it cholera, influenza, Ebola, human immune virus (HIV)/ broke out, the World Health Organization (WHO) declared acquired immune deficiency syndrome, severe acute respira- it a pandemic and named it SARS-COV-2 and the disease tory syndrome (SARS), and now COVID-19. COVID-19 (Gautam 2020; Pei et al. 2020). On February As of the time this paper was written, 203,295,170 11, 2020, WHO termed the disease as COVID-19. The COVID-19 cases had been confirmed, including 4,303,515 name was formed from CO stands for “Corona,” VI stands deaths globally (World Meters Info 2022). The conse- quence of the virus infection is a severe lung injury and respiratory pain disorder that eventually causes pulmonary Responsible Editor: Philippe Garrigues failure and causes death. The virus of COVID-19 is spread Emmanuel Mensah Aboagye through contact with respiratory droplets instead of air. * jaymens001@gmail.com Generally, the virus spreads very fast, and the main way of spreading is through respiratory drops given off by a per- 1 Law School, Zhongnan University of Economics and Law, son suffering from a cold and cough (Aboagye et al. 2022; Wuhan, China Xie and Chen 2020). People who contract this deadly 2 School of Accounting, Zhongnan University of Economics virus show at least some of these symptoms: dry cough, and Law, Wuhan, China fever, and difficulty breathing. Children, older people, and 3 Department Political Science, University of Ghana, Legon, those with health complications like high blood pressure Accra, Ghana Vol.:(012 3456789) Environmental Science and Pollution Research (B.P.), cancer, diabetes, heart problem, and asthma are social lockdowns on air quality. The study pursues the fol- more prone to develop this disease (Chakraborty and lowing objectives explicitly: Maity 2020; Dong et al. 2020). Experts advise everyone to maintain a 1-m social distance, especially away from (a) To assess the suitability and quality of the subject area infected people (Schormans et al. 2021). through the identification of leading authors, patterns, Social lockdowns have been considered an effective and performances of countries or institutions; control measure for fighting the COVID-19 menace (Adam (b) To examine collaborations among institutions and et al. 2021; Arora et al. 2020). Since various governments countries that have enormously contributed to research adopted social lockdowns, it was realized, especially in the in the field of COVID-19 social lockdowns on air qual- first three months, that air pollution had declined. Hence, ity research to unearth the research evolution between experts and researchers could conclude that there was a countries, and “fortune amidst the misfortune” (Aboagye et al. 2021; (c) To find out present hotspots in this knowledge domain Cheval et al. 2020; Desouza et al. 2021). Based on this, based on keyword analysis which may impact and the social lockdown became predominant in reducing the through more light on the possibilities for future transmission of COVID-19, thereby halting most industrial research in the field. activities, transportation, and human mobility. Industries classified as essential are allowed to operate (Muhammad et al. 2020). Explicitly, this research answers the following outlined Consequently, this has impacted Outdoor Air Quality research questions: (OAQ) since there have been many improvements in many parts of the world because the emissions of major air pol- (1) What is the developing trend in this research field? lutants from major sources, such as vehicular traffic and (2) Which journals, subject categories, institutions, and industries, halted mortalities (Adam et al. 2021; Naqvi et al. regions involved in COVID-19 social lockdowns on 2021). This reflection implies that air pollution can directly air quality are prevalent? affect economic growth and human activities (Jin et al. 2016; (3) Who are the most influential authors, and what are their Liu et al. 2021). Globally, due to the restrictions placed on collaborations with COVID-19 social lockdowns on air industrial and human mobility, air quality has improved to quality? 66% (Sathe et al. 2021; Yadav et al. 2020). Since COVID-19, (4) What are the current research’s authorship output, cita- several global experiments have improved our understanding tion, and co-citation structure? of air pollution, air quality concerns, and their effects. These (5) What are the prevalent developing themes in COVID- scientific results that have been concluded will serve as a 19 social lockdowns on air quality research and areas source and basis for formulating and enacting environmen- that need further studies? tal laws and policies to improve air quality (Marinello et al. 2021; Mehmood et al. 2022; Zangari et al. 2020). During the The current study’s findings provide practical recommen- lockdown, numerous cities reported lower atmospheric con- dations for future research and offer a model for environ- centrations of key air pollutants like particulate matter (PM; mental and health scientists to examine the potential impact PM10 and P M2.5), nitrogen dioxide (NO2), carbon monoxide of the COVID-19 social lockdowns on urban air pollution. (CO), sulfur dioxide (SO2), and ozone (O3) (Filonchyk et al. The change in air quality has been studied based on 2020; Filonchyk and Peterson 2020). measurements of these criteria air pollutants at regular Some researchers have explored several researches with fixed monitoring stations and satellite-based observations different methods to find the impact of COVID-19 social (Aboagye et al. 2021; Alvarez et al. 2020; Desouza et al. lockdowns on air quality (see Table 1). Although the cur- 2021; Fuwape et al. 2021; Smith et al. 2020; Venter and rent study attempts to emphasize global COVID-19 social Louren 2021). On the contrary, not all cities experience an lockdowns and improved air quality, it contributes consid- outright improvement in air quality. In this period, some erably to the literature in other ways than previous studies countries experienced worse air pollution, thus observing (Table 1). The researchers adopt a bibliometric analysis to a worsening air quality. These variations in experimental assess the global impacts of COVID-19 social lockdowns data might be due to variations in meteorological factors on air quality from January 2020 to September 2022. Thus, or the role of atmospheric interaction while having clear the current study aims to offer a straightforward analysis skies. For instance, the surface levels of O3, a secondary of the evolution of published articles on COVID-19 social air pollutant, have frequently been reported to be stable or lockdowns on air quality as well as emerging benefits and even increasing (Liu et al. 2021; Zoran et al. 2020). These challenges of COVID-19 social lockdowns on air quality unexpected findings should be studied to improve our under- while discussing the future research areas of COVID-19 standing of secondary air pollutants, their movement and 1 3 Environmental Science and Pollution Research 1 3 Table 1 Comparison of previous studies of COVID-19 social lockdown and air-quality Author Article title Time period Keywords Focus of study Methodology Findings Casado-Aranda and S´anchez- Analysis of the scientific December 2019 to September Environmental studies, Bib- Analyzed 440 articles to Bibliometric analysis The findings of the study Fern´andez (2021) production of the effect of 2020 liometric analysis, SciMAT, explore the relationship revealed that the scientific COVID-19 on the environ- COVID-19, Coronavirus between the effect of the production related to the topic ment: A bibliometric study Pandemic, Journalism, Com- COVID-19 pandemic on the of COVID-19, and the envi- munication Mass media food supply chain and waste ronment has increased signifi- habits actions to mitigate cantly since the beginning of climate change the pandemic. The study also found that the most researched areas were air pollution and the impact of the pandemic on greenhouse gas emissions. Bao and Zhang (2020) Does lockdown reduce air Between 1 January and 21 Travel restriction, Air pol- Expounded on the impact of Survey Their study showed that a pollution? Evidence from 44 March 2020 lution, Human mobility, COVID-19 on the reduction decline in air pollution posi- cities in northern China Dynamic panel Covid-19 in pollution in 44 cities in tively correlated with travel northern China restrictions. Jain and Sharma (2020) Social and travel lockdown - Interpolation technique, Arc To assess the overall impact of Survey Revealed that the concentration impact considering coronavi- GIS, Air quality, Vulnerabil- social and travel lockdown of P M2.5, PM10, N O2, and rus disease ( COVID-19 ) on ity, Environmental health in five megacities of India; CO declined by ~41% (66–39 air quality in Megacities of Delhi, Mumbai, Chennai, μg m–3), ~52% (153–73 μg India: present benefits, future Kolkata, and Bangalore. m–3), ~51% (39–19 μg m–3), challenges and way forward The study evaluated the and ~28% (0.9–0.65 mg m–3) spatiotemporal variations in during the lockdown phase in five criteria pollutants over comparison to the before lock- two time periods down in Delhi, respectively Aboagye et al. (2021) “Fortune amidst misfortune”: 2020 Air pollution, air quality, To unravel how air pollution Observation/evidence captured In a related study, the research- the impact of COVID-19 city COVID-19, Coronavirus, intensified COVID-19-asso- by Sentinel-5 satellite ers found that exposure to lockdowns on air quality CO, S O2, N O2 ciated mortality or morbidity long-term air pollutants in China, Italy, and the USA. ( PM10, PM2.5, NO2, and O3) was positively correlated with COVID-19 cases Bhatti et al. (2022) Air pollution; air quality; Air pollution, COVID-19, This study investigates the Trajectory analysis Although the COVID-19 COVID-19; coronavirus; Particulate matter, China change in air pollution pandemic had numerous nega- CO; SO2; NO2 (focusing on the Air Quality tive effects on human health Index (AQI) and the global economy, the reduction in air pollution and significant improvement in ambient air quality likely had substantial short-term health benefits; the government must implement policies to control post-COVID environmental issue (Aamir et al. 2021) Spatiotemporal change of 2019 to 2021 air pollution, COVID-19, To study the impact of the Survey Although the COVID-19 air-quality patterns in Hubei particulate matter, China strict control measures of the pandemic had numerous nega- province—a pre-to post- new COVID-19 epidemic on tive effects on human health COVID-19 analysis using the air quality of Hubei in and the global economy, it is path analysis and regression early 2020 likely that the reduction in air pollution and the significant improvement in ambient air quality due to lockdowns pro- vided substantial short-term health benefits Environmental Science and Pollution Research 1 3 Table 1 (continued) Author Article title Time period Keywords Focus of study Methodology Findings Hasnain et al. (2022) Time series analysis and 2022 prophet forecasting model, The current study aimed to Survey PFM has extensive power to forecasting of air pollutants time series model, air pol- predict both short-term and accurately predict the con- based on prophet forecasting lution, machine learning, long-term air pollution in centrations of air pollutants model in Jiangsu province, Jiangsu province, China Jiangsu province, China, and can be used to forecast air China based on the prophet fore- pollution in other regions. casting model (PFM). We Present Study A bibliometric analysis of the 2020 and 2022 Covid-19, social lockdowns, This research adopted the Bibliometric analysis Air pollution plagues China, impact of COVID-19 social air pollution, bibliometric bibliometric approach from India, and the USA, prompt- lockdowns on air quality: analysis, citation analysis a global perspective to meas- ing many studies. After a research trends and future ure the impact of COVID-19 high spike in 2020, research directions social lockdowns on air published in 2021 declined pollution while identifying in 2022. Authors keywords the evolving problems and have focused on “COVID-19,” discussing the future view- “air pollution,” “lockdown,” points during the ongoing and “PM25.” These keywords COVID-19 pandemic. suggest that research in this area is focused on understand- ing the health impacts of air pollution, developing policies to address air pollution, and improving air quality monitor- ing. NB: comparison of previous studies of COVID-19 social lockdown and air quality and the present study Environmental Science and Pollution Research evolution under diverse meteorological circumstances, their The search terms for this review article were TOPIC: health effects, and current air pollution management meth- (“corona virus lockdown*” OR “Covid-19 lockdown*” ods. The social lockdown intervention that various govern- OR “covid 19 lockdown*” OR “coronavirus lockdown*” ments implemented suggested that people stay home, thus (Topic) and “air quality” OR “low air pollution”) set to spending their time in their indoor environment. As a result, a timespan of January 01, 2020–September 12, 2022. PM and Volatile Organic Compound (VOC) emissions from The search generated 517 documents, further filtered by day-to-day activities such as cooking, cleaning, and smok- the researchers based on document type and language. ing can expose indoor dwellers to toxic air pollutants (Pei Hence, the final document used for further analysis was et al. 2020). 504. Figure 1 is the flowchart of data analysis procedures In making a review study, bibliometric analysis has employed in the study. proven to be an effective and most widely scientific research approach, adopted in many fields of study. It helps disci- Analyzing data using CiteSpace software plines to determine the structure and characteristics of a field of study by mapping the distribution, scalar relationship, and CiteSpace is among the commonly used tools for imagery change regulation of literature and information (Mao et al. and visualization in scientific research (Chen 2006a, Chen 2015). Recently, many researchers have adopted a biblio- et al. 2010). The CiteSpace software is an open-source metric approach and other review approaches in COVID-19 Java application that cites and classifies information lockdowns and improvements in air quality and food supply on related literature and continues to produce a graphic chain research. Researchers must be able to expound on and representation of the data generated (Chen et al. 2014a). describe the exact situation in current review research, hot Two components make up CiteSpace’s visualization and topical issues, trends in future research fields in COVID-19, mappings, thus, nodes and links. The nodes represent and social lockdown on air pollution. This could be done authors, institutions, countries/regions, journals, key- through critical surveying and summarizing related litera- words, subject groupings, and cited references. At the ture; nonetheless, the researchers found that there is little same time, links replicate the co-occurrence or co-citation research that focuses on COVID-19 and social lockdown on association between nodes (Chen et al. 2014b). The physi- air pollution via a bibliometric approach. Based on the Web cal characteristics of the nodes are such that they usually of Science Core Collection (WoS), several scholars have define the evolution and growth of a research domain. contributed to COVID-19 social lockdowns and air quality The researchers analyzed the general characteristics of in diverse ways. This has been summarized in Table 1. academic research published on COVID-19 and air qual- ity, conducting a collaboration analysis to plot the coop- eration links between authors and countries in this area. Materials and methods To give more understanding of the academic structure of the research area, the researchers continued to conduct Data sources co-citation of the documents and journals. CiteSpace was then used to track COVID-19 social lockdowns and The bibliometric analysis uses scientific, arithmetic, and air quality research by identifying and cataloging key statistical approaches to investigate the document struc- research areas, development, and current status. Zhang ture types, features, and forms by taking documents as et al. (2020a) suggest that CiteSpace parameters, such as the research object. The researchers gathered data for time slice, node type, and pruning, must be thoroughly this study through the Core Collection of Web of Science checked and selected in concinnity with the study’s (WoS) collected by Thomas Reuters and jointly integrated objectives. In this regard, the researchers set the study into the ISI Web of Knowledge. WoS is a generally adopted parameters to (a) time slicing: 2020–2022; (b) years per catalog that gives statistics on document types, language, slice: 1; (c) node type: country, author, keyword, and countries/regions, institutions and authors, funding agen- cited journal; (d) network selection criteria based on top cies, journals, and subject groups and types. WoS allow the N = 50; (e) link strength and scope: cosine and within researcher(s) to download all records and cited references slices, respectively. of articles published in .txt format. The researcher(s) can use the .txt to generate maps and analyze data in other soft- The measure of influence: h‑index and impact factor ware. For this review article, the researchers downloaded academic publications on the impacts of COVID-19 social For the researchers to best measure the cumulative impact lockdowns on air pollution from the WoS database on Sep- and significance of an individual’s scientific output with tember 12, 2022. the advantage of being unbiased, the researchers adopted the h-index as proposed by Hirsch in 2005 (Hirsch 2005). 1 3 Environmental Science and Pollution Research In this vein, one is associated with a particular article a similar trend as the number of publications. The year 2021 published and may be an author, country, or journal. recorded the highest citations. There was a sharp increase from Brandão and Soares de Mello (2019) add that the h-index 2020 to 2021, but those recorded in 2022 were lesser than in is linked to a particular period that the h papers from an 2022. The 504 and have been cited 7495 times. Moreover, the individual have been cited at least h times. Hence, the vast number of citations between 2020 and 2021 may be asso- researchers used this index based on the total number ciated with the sharply increased number of articles published of citations and publications in this study. Impact factor between the periods. Essentially, research on the COVID-19 (IF) is another significant performance indicator widely lockdown and its effects on air pollution is still beginning and used to assess the quality of journals. IF represents the has received many scholarly citations. source’s mean citations metric of journal articles pub- Based on the document content analysis, there were 919 lished over 2 years (Ma et al. 2018). The researchers, total keyword plus (ID) and 1054 author keywords (DE). therefore, obtained the IF of top-performing journals Also, the study recorded 2607 author appearances, 12 sin- from the Citation Reports (JCR) 2019 edition. gle-author documents, and 2595 multi-authored documents. It was realized that this study’s co-author per document and international co-authorship were 6.43 and 39.88, respec- Results and discussion tively (Table 2). This indicates that many authors partici- pated in the COVID-19 social lockdown and air pollution, The characteristic of scientific production underscoring this research theme’s significance. Of the 504 documents, original articles of 484 took the lead- Scientific collaboration between countries ing number of retrieved publications and constituted 96.03% of the total, while articles with early access constituted 20 of the The scientific collaboration of different categories was entire documents and represented 3.97% (Table 2). The trends also assessed based on the affiliation of at least one article in the number of publications and citations are presented in author. Overall, some authors from 57 countries contrib- Fig. 2. Generally, between 2020 and 2022, there were several uted to articles regarding COVID-19 social lockdowns and publications. However, there were fluctuations in the number air pollution. Table 3 presents the first 20 most productive of publications. It could be realized that there was a quick rise countries where these authors who have contributed to in publications from 2020 to 2021. Thus, there was a signifi- these discussions are affiliated, consisting of nine coun- cant increase in the number of publications in this period. Also, tries from Europe, six countries from Asia, four countries there was a sharp decrease in publications from 2021 to 2022, from America, and one from Australia. China was ranked mainly because our study did not cover the entire 2022. By the first based on its document output of 151, which constitutes end of the year, additional publications will plausibly increase 29.96% of the total output and has the highest citations, the total number of publications in 2022. Citations also took similar to the study by Mehmood et al. (2022). This shows Fig. 1 Flow chart of bibliomet- ric analysis on COVID-19 and air quality research from 2020 to 2022 1 3 Environmental Science and Pollution Research Table 2 Basic information on scientific publications used in this respectively, with an MCP ratio of 0.287 (Table 2). The study USA was ranked third with 41 documents representing Description Results 8.13% of the total output and recorded SCP of 14 and SCP of 27 with an MCP ratio of 0.659. By qualitative infer- Main information about the data ences, articles from China, India, and the USA have gained Timespan 2020:2022 3228, 1092, and 1684, respectively. Figure 3 demonstrates Sources (journals) 138 the geographical dissemination of all countries involved in Documents 504 this study’s subject research. Based on the study’s timeline, Average citations per doc 14.8 the initial countries in this field are China, India, and the References 15,322 USA, with publications from 2020. Most of the remaining Authors countries started producing publications in 2021. Figure 4 Authors 2607 shows the collaboration network of countries with more Authors of single-authored docs 12 than ten publications. The network consisted of 76 nodes Document contents with 112 links. The network density of 0.0393 indicates Keyword plus (ID) 919 that the countries’ connections are moderately tight. It was Author’s keywords (DE) 1054 noted that the countries with the most published articles Authors collaboration have a closer relationship. China, New Zealand, England, Single-authored docs 13 and the Netherlands were key nodes in connecting groups Co-authors per doc 6.43 of large nodes due to their high centrality of 0.45, 0.43, International co-authorships % 39.88 0.28, and 0.26, respectively. Document types Altogether, China, India, and the USA have contributed posi- Article 484 tively to the COVID-19 social lockdown and air quality research. Article; early access 20 This has been so as several scholars (Bao and Zhang 2020; He et al. 2020) assert that the COVID-19 pandemic first emerged in Wuhan, China, and quickly spread worldwide. From a country- that China is the first country to introduce research on the level perspective, China, India, and the USA were the leading theme related to the impact of COVID-19 social lockdowns countries working on COVID-19 and air pollution research. In on air pollution. contrast, England, France, Italy, Germany, and Switzerland con- The single country publication (SCP) and multiple tributed positively to this discourse. It can also be identified in country publications (MCP) were 94 and 57, respectively, Table 2 that, aside from China and India, most of the productive with a 0.337 MCP ratio (Table 2). India came up second countries are based in Europe. This can be associated with the with 101 documents representing 20.04% of the total high collaborative network among European countries. output. India also recorded SCP and MCP of 72 and 29, Fig. 2 Annual distribution of publications and citations Research Output (2020 - 2022) 350 4500 300 4000 3500 250 3000 200 2500 150 2000 1500 100 1000 50 500 0 0 2020 2021 2022 Number of publica ons Total Cita ons 1 3 Environmental Science and Pollution Research Table 3 Countries’ scientific productivity Most productive journals and journal co‑citation Country NP SCP MCP F MCP_ratio analysis China 151 94 57 0.3 0.377 This section of the paper expounds on active journal analy- India 101 72 29 0.2 0.287 sis, which aids research scholars in understanding how arti- USA 41 14 27 0.081 0.659 cles related to COVID-19 social lockdowns are distributed Italy 25 18 7 0.05 0.28 across journals while selecting the top journals to publish UK 22 12 10 0.044 0.455 their related research works. The 504 documents retrieved Spain 18 17 1 0.036 0.056 for this study regarding the impact of COVID-19 social lock- Canada 8 5 3 0.016 0.375 downs from 2020 to 2022 were published in 138 journals. Germany 8 3 5 0.016 0.625 Twelve (8.69%) comprised ten or more published articles. Australia 7 2 5 0.014 0.714 Table 4 presents the performance of the top 20 most produc- Kazakhstan 7 4 3 0.014 0.429 tive journals, representing 54.76% of the total document. Saudi Arabia 7 5 2 0.014 0.286 The two most productive journals with regards to the num- France 6 3 3 0.012 0.5 ber of publications and h-index were Atmosphere (IF 2021, Greece 6 1 5 0.012 0.833 3.110; NP = 38, 7.54%) and Science of the Total Environ- Poland 6 6 0 0.012 0 ment (IF 2021 = 10.753; NP = 37, 7.34%); however, Atmos- Malaysia 5 1 4 0.01 0.8 phere and Science of the Total Environment are ranked 20th Turkey 5 5 0 0.01 0 in terms of IF. Despite being ranked 19th in terms of the Mexico 4 3 1 0.008 0.25 number of articles published (IF 2021 = 11.558; NP = 6, Norway 4 1 3 0.008 0.75 1.19%), Environmental Science & Technology Letters was United Arab Emirates 4 1 3 0.008 0.75 the most productive journal in terms of IF and placed 12th Argentina 3 1 2 0.006 0.667 in terms of citations. This shows the quality of articles pub- NP, number of publications; F, frequency; SCP, single-country publi- lished in this journal. cations; MCP, multiple country publications Fig. 3 Global distribution of all countries/regions that have conducted studies on the impact of COVID-19 social lockdowns and air quality between 2020 and 2022 1 3 Environmental Science and Pollution Research Fig. 4 Academic collabora- tion among the most produc- tive countries. Note: purple rings represent the degree of centrality; node size depicts the frequency of publications The most productive journals based on IF, especially Sci- COVID-19 social lockdown and air pollution. The sci- ence of the Total Environment, Environmental Science & entific community has a vital role in research improve- Technology Letters, Journal of Cleaner Production, and Envi- ments, and their published research output indicates the ronmental Pollution (Table 4) in this research field are usu- level of their analysis. Besides, the co-citation and citation ally interdisciplinary, encapsulating the total environment that connections illustrate the metrics of the researcher and interfaces the biosphere, atmosphere, lithosphere and anthrop- aid researchers in understanding the implication of the osphere, air quality, global change, effects on the environment, research work on this theme. Table 5 displays this group environmental health sciences, and public health. of authors, constituting 0.38% of the total authors partici- Journal co-citation analysis refers to when the same paper pating in the current study. However, their publications cites two journals (Afrane et al. 2022a, b). Figure 5 displays represent 14.68% of the total publications retrieved for the co-citation link of the most productive journals. The this study. According to the number of publications, Wang network comprises a total of 67 nodes and 70 links. Minor Y., Li L., Wang H.L., Kumar S., and Liao H. were the top journals seemed unlabeled in the network because they did 5 publishing authors and emerged first based on h-index not meet the set threshold for the analysis. The three journals rankings. Furthermore, Fu Q.Y. is the most globally cited with the most co-citations were Science of the Total Envi- author. ronment, Atmosphere, and Environmental Pollution, with In addition, the academic co-authorship among influen- co-citation frequencies of 434, 360, and 315, respectively. tial authors was analyzed and displayed in Fig. 6. Figure 6 shows that Shi et al. (2021) have collaborated to publish an article in Science Advances on “Abrupt but smaller Author analysis and highly impactful work than expected changes in surface air quality attributable to COVID-19 lockdowns.” In this paper, the authors unrave- This section of the research presents the performance of led and concluded on the need for sophisticated analysis the top 10 authors leading the research on the impact of to quantify the air quality impacts of interventions and 1 3 Environmental Science and Pollution Research Table 4 Journal metric Element H_index G_index M_index TC NP IF analysis related to the impact of the COVID-19 pandemic Science of the Total Environment 16 37 5.333 1741 37 10.753 lockdowns and air pollution Aerosol and Air Quality Research 10 20 3.333 454 32 4.530 Atmosphere 10 15 3.333 271 38 3.110 Atmospheric Chemistry and Physics 9 16 3 265 23 7.197 Environmental Pollution 9 16 4.5 279 26 9.988 Geophysical Research Letters 9 17 3 385 17 5.576 Environmental Research 8 13 4 170 16 8.431 Remote Sensing 8 12 2.667 157 17 5.349 Air Quality Atmosphere and Health 6 10 - 204 10 5.804 Environmental Science and Pollution Research 6 9 - 85 13 5.190 Atmospheric Pollution Research 5 9 2.5 86 10 4.831 Environment Development and Sustainability 5 7 - 155 7 4.080 Environmental Research Letters 5 7 2.5 62 8 6.947 International Journal of Environmental 5 7 1.667 55 14 4.614 Research and Public Health Journal of Cleaner Production 5 5 2.5 78 5 11.072 Journal of Environmental Sciences 5 9 2.5 119 9 3.120 Scientific Reports 5 6 1.667 101 6 4.996 Sustainable Cities and Society 5 6 1.667 204 6 10.696 Urban Climate 5 9 1.667 82 9 6.663 Environmental Science & Technology Letters 4 6 1.333 141 6 11.558 NP, number of publications; IF, impact factor; TC, total citation indicate that genuine air quality improvements were nota- The researchers further utilized highly impactful arti- bly more limited than some earlier reports or observa- cles to comprehend the implication of a particular area tional data suggested. Sulaymon et al. (2021) published of interest. The highly impactful articles compute a high in Atmospheric Research on “COVID-19 pandemic in document level in a specific subject. Table 6 reflects the Wuhan: ambient air quality and the relationships between highly impactful articles based on total citations related criteria air pollutants and meteorological variables before, to the COVID-19 social lockdown and its impact on air during, and after lockdown.” They discovered that although pollution. The most highly impactful work was “COVID- the COVID-19 pandemic had numerous adverse effects on 19 lockdowns cause global air pollution declines,” pub- human health and the global economy, the reductions in air lished by Venter et al. (2020) in Earth, Atmospheric, and pollution and significant improvement in ambient air qual- Planetary Sciences, with 340 citations which accounts for ity likely had substantial short-term health benefits. This 12.9% of the top fifteen most cited publications. However, study improves the understanding of the mechanisms that all the highly cited documents were published in 2000 lead to air pollution under diverse meteorological condi- and were cited from Science of the Total Environment. tions and suggest effective ways of reducing air pollution This article expounded on the topic under discussion and in Wuhan. Bar et al. (2021) also collaborated to publish found empirical evidence for a link between global vehicle “Impacts of partial to complete COVID-19 lockdown on transportation declines and the reduction of ambient NO2 N O2 and PM2.5 levels in major urban cities of Europe and exposure. The researchers concluded that, while the state US” in Cities.” In the study, the researchers outlined that of global lockdown is not sustainable, there is a potential improvement in air quality during COVID-19 may be tem- for mitigating public health risks by reducing “business as porary. Still, regulatory bodies should learn to reduce air usual” air pollutant emissions from economic activities. pollution long-term concerning the trade-offs between the The second most cited document by Sicard et al. (2020) environment, society, and economic growth. Policymakers takes another dimension. This study highlights the chal- should address the intersection of urban design, health, and lenge of reducing the formation of secondary pollutants the environment to protect public health. Sustainable urban such as O 3, even with strict measures to control primary policies could be adopted to build urban resilience against pollutant emissions. The study revealed that the lockdown future emergencies. effect on O 3 production was 10% higher than the weekend effect in Southern Europe and 38% higher in Wuhan, while 1 3 Environmental Science and Pollution Research Fig. 5 Co-citation network of the most productive journals. Note: purple rings represent the degree of centrality; node size depicts the frequency of co-citations for PM, the lockdown had the same effect as weekends in document’s objectives, methods, and perspectives (Afrane Southern Europe. et al. 2022a, b; Agyepong and Liang 2022; Effah et al. 2022; Jin et al. 2022). The author keyword is the list of keywords Keyword analysis: current and future perspectives in the article and is a useful part of data for the scientific community on research-changing aspects and evaluations Keyword analysis and research hotspot (Chen 2006; Zhang et al. 2020a). The keyword plus on the other hand is created from the titles of the cited documents By analyzing the frequency of keyword occurrence, a and denotes an expanded scope of the search to capture rel- researcher may find beneficial information such as a evant and related terms (Afrane et al. 2022a, b; Zhang and 1 3 Environmental Science and Pollution Research Table 5 Top 10 performing authors lockdown and for keyword plus pollution, air quality, impact, Authors Number of publications Total citation h-index and PM2.5 have been the top 4 across all research studies. It is worth mentioning that there were not many differences Wang Y. 11 152 6 in the research trends of the overall author keyword and Li L. 8 354 5 keyword plus results. The basic difference is that some of Wang H.L. 8 144 5 the author’s keywords, like COVID-19 and SARS-COV-2, Kumar S. 7 143 5 were not prominent in the keyword plus domain. Moreso, Liao H. 7 121 3 Fig. 8 showed that P M10 generally was not prominent in the Liu C. 7 29 3 study in both author keyword and keyword plus in the top Zhang J. 7 104 5 50 author keywords and keyword plus. Zhao T.L. 7 94 4 The section is concluded with the main research direction Fu Q.Y. 6 351 3 of the most productive countries/regions and journals. In Hu J.L. 6 63 2 Fig. 9, a three-field plot is created with the top 10 countries on the left, the top 10 journals on the right, and the top 10 keywords in the middle. Based on the figure, it can be real- Liang 2020). Keywords and keyword plus analyses suggest ized that the top 5 keywords from these ten nations are the a practical method to find new research prospects on a spe- same as the global, as shown in Fig. 6. This validates the cific theme (Afrane et al. 2022a, b; Khan et al. 2021; Zhang notion that the research direction is frequently determined by et al. 2020b). The researchers adopted CiteSpace to map the these ten nations, especially China, India, and the USA. The keyword co-occurrence network to comprehend the progress top 10 journals had contributed to publication employing the of research interests and find hotspots in this field. So, the top ten keywords as seen in the figure. co-occurrence and frequency analysis of keywords and key- The development of broad and main themes is captured word plus may help determine hot topics and boundaries in a using a thematic evolution mapping, as displayed in Fig. 10. research field (Chen et al. 2016; Huang et al. 2020). This figure shows the influence of COVID-19 social lock- The data gathered, as shown in Table 6, displays that the downs on urban air quality throughout the novel virus’s most frequently occurring author keywords were “Covid-19” propagation from 2020 to 2022 and how the research trend (238), “Air-quality” (126), “Lockdown” (111), “Air-pollu- will continue into 2023 and beyond. The year 2021 was the tion” (89), “Covid-19 lockdown” (63), “PM ” (53), “NO ” timeline’s cutting point, given the study’s coverage. The net-2.5 2 (42), “Particulate Matter” (31), “Ozone” (27), and “PM ” work of lines connecting one theme to another illustrates 10 (23), involving the implication of evaluating the impact of how a theme’s research emphasis has developed with time. COVID-19 on the air pollution topic. In descending order, The bigger the size of the network, the more significant the keywords with the highest centrality in the network were themes’ influence in that period is. improved air quality, pollution, impact, emissions, and The research started with ten major themes: meteorol- Covid-19 lockdowns (Fig. 7). Similarly, the keyword plus ogy, COVID-19 lockdown, traffic, aerosol, COVID-19, aero- network showed that the most frequent words were “Pol- sol optical depth (AOD), particulate matter, N O2, sentinel lution”(122), “Impact” (105), “Air-quality”(90), “PM ” 5-p, emission, and remote sensing. Some themes, such as 2.5 (84), “Ozone” (68), “Quality” (60), “Emissions” (58), and COVID-19, remained constant in the top 5 since the starting “Particulate Matter” (51) (Table 7). period and accounted for the largest theme. COVID-19 can, Figure 7 shows the co-occurrence network of keywords thus, be described as a core study area in this research field. that appeared more than ten times. The size of the circle is Furthermore, themes such as NO2 and particulate matter proportional to the keyword frequency, while the lines con- were essential themes during the initial stages of the corona- necting the nodes show the relationship between keywords. virus outbreak (2000–2021) but declined within 2020–2023. The network comprised 107 nodes and 361 links with a den- However, the attention on the AOD has been revitalized in sity of 0.06. The tight structure of the network indicates that recent years and, thus, a major theme in 2022–2023 (AOD), the keywords are closely interlinked. coupled with research on the COVID-19 pandemic. The main research direction of the impact of COVID-19 social lockdowns is highlighted in Fig. 8 according to the Current and future perspectives frequently occurring author keywords and keyword plus. It can be concluded that research focus using both author Recent air pollution research highlights that half of the annual keyword and keyword plus have fairly been the same infer- premature deaths in China, India, and the USA result from ring from the figure. In no systematic order, for author key- indoor air pollution (Dedoussi et al. 2020; Jyoti 2020; Tohno word analysis, COVID-19, air quality, air pollution, and and Chatani 2021). Subsequently, the recent COVID-19 social 1 3 Environmental Science and Pollution Research Fig. 6 Academic collaboration among the top 10 most productive authors lockdown has proven that we can improve and achieve better COVID-19 lockdowns on air quality, highlighting how pollu- air quality and a clean environment (Arora et al. 2020; Venter tion and emission levels reduced during those lockdowns peri- et al. 2020). The WHO estimates that about 4.2 million people ods and how the identified pollutants have significant impacts die from ambient air pollution yearly. They further project that on air quality and public health. air pollution is also associated with 26% of deaths caused by For instance, Terpi and Czwojdzi (2021) concluded that respiratory disorders, 25% of deaths from chronic obstructive P M10 was associated with COVID-19 incidence and mortal- pulmonary disease (COPD), and 17% of deaths from heart ity in different provinces only in certain months. Namdar- attacks and strokes (Isaifan 2020; Khan et al. 2021). The find- khojasteh et al. (2022) analyzed the relationships between ings from the keyword analysis in Figs. 7, 8, and 9 show that COVID-19 cases and both short-term (6 months) and long- much of the current research has focused on the impacts of term (60 months) exposures to eight air pollutants (NO, 1 3 Environmental Science and Pollution Research Table 6 Highly impactful articles based on total citations during 2020–2022 Articles Journal Total citations Reference COVID-19 lockdowns cause global air pollution declines Earth, Atmospheric, and Planetary Sciences 340 Venter et al. 2020 Amplified ozone pollution in cities during the COVID- Science of the Total Environment 334 Sicard et al. 2020 19 lockdown Enhanced secondary pollution offset reduction of pri- National Science Review 332 Qi et al. 2020 mary emissions during COVID-19 lockdown in China The short-term impacts of COVID-19 lockdown on Nature Sustainability 288 He et al. 2020 urban air pollution in China Air quality changes during the COVID-19 lockdown Science of The Total Environment 270 Li et al. 2020 over the Yangtze River Delta Region: an insight into the impact of human activity pattern changes on air pollution variation Assessing air quality changes in large cities during Science of The Total Environment 217 Kerimray et al. 2020 COVID-19 lockdowns: the impacts of traffic-free urban conditions in Almaty, Kazakhstan COVID-19 lockdown effects on air quality by N O2 in the Science of The Total Environment 195 Baldasano, 2020 cities of Barcelona and Madrid (Spain) Temporary reduction in fine particulate matter due to Sustainable Cities and Society 126 Kumar et al. 2020 “anthropogenic emissions switch-off” during COVID- 19 lockdown in Indian cities Response of major air pollutants to COVID-19 lock- Science of The Total Environment 101 Pei et al. 2020 downs in China Disentangling the Impact of the COVID-19 lockdowns Geophysical Research Letters 101 Goldberg et al. 2020 on urban NO2 from natural variability Short-term and long-term health impacts of air pollution The Lancet Planetary Health 95 Giani et al. 2020 reductions from COVID-19 lockdowns in China and Europe: a modelling study The COVID-19 lockdowns: a window into the earth Perspectives 90 Diffenbaugh et al. 2020 system Nonuniform impacts of COVID-19 lockdown on air Science of The Total Environment 84 Chen et al. 2020 quality over the USA Impact of COVID-19 lockdown on NO2, O 3, P M2.5, and Science of The Total Environment 82 Hashim et al. 2021 PM10 concentrations and assessing air quality changes in Baghdad, Iraq Abrupt but smaller than expected changes in surface air Science Advances 81 Shi et al. 2021 quality attributable to COVID-19 lockdowns NO2, NOx, CO, S O2, O3, PM2.5, and P M10) in Tehran city, India. They concluded that if explicit pollutants and other Iran. They found that exposure to air pollutants can increase factors play a considerable role in COVID-19 infection, it the number of infected people by transmitting the virus has strong implications for any mitigation strategy develop- through the air or predisposing people to the disease over ment to curtail the spreading of the respiratory disease. The time. Also, Travaglio et al. (2021) explored potential links findings of the highlighted studies suggest that in a particular between major fossil fuel-related air pollutants and SARS- geographical area with high air pollution, there is a like- CoV-2 mortality in England. They compared current SARS- lihood of a higher outbreak and spread of the COVID-19 CoV-2 cases and deaths from public databases to regional pandemic compared to areas with less air pollution. Hence, and subregional air pollution data monitored at multiple air pollution must drop during the COVID-19 pandemic to sites across England. They found that a small increase in air save human lives. pollution leads to a large increase in England’s COVID-19 COVID-19, to many, looked unending, but the quick infectivity and mortality rate. countermeasure, especially the social lockdown adopted Chattopadhyay and Shaw (2021) also empirically by various governments across the globe, has been very explored the relationship between exposure to air pollut- effective in solving many environmental issues that were ants, that is, sulfur dioxide, nitrogen dioxide, and particulate costly to fight. Although the COVID-19 social lockdowns matter ( SO2, N O2, and P M10) and COVID-19 infection at were adopted as a temporal countermeasure, they have posi- the smallest administrative level (ward) of Mumbai City in tively impacted the environment, significantly improving air 1 3 Environmental Science and Pollution Research Fig. 7 Author keyword co- occurrence quality in various geographical locations. The most vulner- city of Santander, and CO, S O2, and P M10 in some cities, able people to COVID-19 are those living in poor air quality but resulted in an increase of O 3 level. Wang et al. (2021) geographical areas, especially with high PM concentrations exploited the impact of pandemic-induced human mobility (Domingo et al. 2020). However, due to the emergence of restrictions on urban air quality across China in response to COVID-19 and the quick adoption of the COVID-19 social the COVID-19 pandemic. Their findings shed new light on lockdowns, various countries are in a better position to the role of a policy intervention in pollution emissions while develop a cleaner future for upcoming generations. also providing a roadmap for future research on the pollution For instance, Briz-redón et al. (2021) investigated the effect of the COVID-19 pandemic. Seo et al. (2020) also impact of a short-term lockdown from March 15 to April contributed to this ongoing discussion in Korea by compar- 12, 2020, on the atmospheric levels of CO, SO2, P M10, O 3, ing the air quality between 2020 and the previous 3 years, and NO2 over 11 representative Spanish cities. The results focusing on the two cities (Seoul and Daegu) where corona- show that the 4-week lockdown significantly reduced the virus is spreading faster. In both cities, they found a signifi- atmospheric levels of N O2 in all cities, except for the small cant decrease in PM2.5, P M10, CO, and NO2. Consequently, the effects of social lockdowns have maximized improve- Table 7 Author keyword and author keyword plus networks ments in air quality due to reduced transboundary pollutants. Author keywords Total counts Keyword plus Total counts Figures 8 and 10 also illustrate the future perspectives of research in this area, with future combat strategies have Covid-19 238 Pollution 122 been displayed in Fig. 11. Results suggest that future stud- Air-quality 126 Impact 105 ies may still consider how for example, the remote sensing Lockdown 111 Air-quality 90 capabilities of Tropomi can aid in improving air quality by Air-pollution 89 PM2.5 84 providing valuable information about atmospheric pollutants Covid-19 lockdown 63 Ozone 68 so policy and mitigation efforts can be implanted to reduce PM2.5 53 Quality 60 pollution and protect human health. Others can also examine NO2 42 Emissions 58 the use of Sentinel-5p data to map the ambient PM and Particulate Matter 31 Particulate Matter 51 2.5examine changes in AOD during the COVID-19 lockdown Ozone 27 China 46 period, even across areas in a particular country or across PM10 23 Trends 46 countries so that valuable information will help understand 1 3 Environmental Science and Pollution Research Fig. 8 Word cloud network. (a) Author keyword and (b) keyword plus atmospheric aerosols effects on the environment and peo- adequately and need to be dropped (Ballester et al. 2008; Ebisu ple’s health. They can be used to support initiatives to moni- and Bell 2012; Amnuaylojaroen et al. 2022). Policies and strate- tor and enhance air quality. Based on Fig. 8, future research gies that safeguard people from the adverse consequences of air can also examine the contributions of the AOD to air quality pollution are undoubted to protect and reduce COVID-19 deaths taking a clue from the COVID-19 social lockdowns. Also, attributed to air pollution. Furthermore, as already explored, air other researchers can explore more on the situation of India pollution has been associated with chronic ailments like COPD, as the country is heavily affected by pollution. Asthma, Inflammatory lung cancer, and other heart diseases Based on the discussions so far, it could be inferred that air (Aboagye et al. 2021). These ailments have also contributed to pollution has had an adverse effect on lung and heart diseases, the hospitalization of several COVID-19 patients to the intensive which has called for quick mitigation strategies. The WHO care unit (ICU) and have resulted in other fatalities. As a result, and US-Environmental Protection Agency (US-EPA) guide- there is concern about the adverse impact of air pollution on lines for PM2.5 and NO2 do not specifically protect humans the COVID-19 pandemic. This calls for in-depth research to Fig. 9 Main research direction of top 10 countries/regions and journals (AU_CO, author country; DE, keywords; SO, journals) 1 3 Environmental Science and Pollution Research Fig. 10 Thematic evolution of the impact of COVID-19 social lockdown on air-quality explore the measure of this auxiliary effect of air pollution on the Implications of this study COVID-19 pandemic. Also, on a fast-paced show, conclusions from other studies have shown that inhabitants of highly pol- Several implications can be drawn from this review article for luted cities risk being infected with COVID-19, showing most analyzing the scientific productivity of the effect of COVID-19 symptoms after the quick spread. COVID-19 and air pollution on air pollution. This discussion provided data and significant are interconnected to population density and spatial issues. By information to help future researchers, policymakers, govern- implication, there is a need for more distinct research to explore ment officials, and other stakeholders understand and appreciate the advancements of the COVID-19 issues in a differentiated the roles of countries, authors, and specific research themes group across various continents. of air pollution or air quality inferred from COVID-19 social The COVID-19 pandemic and air pollution go hand lockdowns on environmental sustainability. Thus, this research in hand, and the lockdown procedures have been relaxed explained the influence of each country’s research productivity in most countries. Both air pollution and COVID-19 and prominent authors associated with COVID-19 social lock- have perhaps unsettled the disadvantaged populaces downs and air pollution research at a global level. more severely due to higher exposure rates. As a result, The literature presents extensive evidence on existing actions to lower the adverse effect of both COVID-19 and themes and points of view for further research by identifying air pollution should be concentrated on disadvantaged highly impactful research hotspots. For example, the assess- groups in particular, where the need is critical (Aboagye ment and discussions on the scientific country productivity et al. 2022; Banks et al. 2020; United Nations 2020). indicate the research significance of a specific country in the Fundamentally, we cannot associate a bright side to the future. Equally, a highly impactful article implies the impor- novel COVID-19 pandemic due to the several losses of tance of the research for a particular topic of interest which lives; nevertheless, these research discussions suggest can be discussed with other bibliometric considerations, the provision of health benefits from air pollution reduc- such as relationships and the number of citations. Due to tions by reducing human mobility and industrial activi- new COVID-19 waves or variants worldwide, environmen- ties. Hence, there is a fortune amidst this misfortune tal researchers should investigate these concerns, especially (Aboagye et al. 2021). using a bibliometric approach, to gain a deep understanding of present and future studies. 1 3 Environmental Science and Pollution Research Source: Authors construct Fig. 11 Impact of air pollution on the COVID-19 pandemic and future combat strategies Conclusion and limitations and Aerosol and Air Quality Research (32, 6.35%). Regard- ing the qualitative part, Venter et al.’s (2020) contributions This current study analyzed data gathered from the Web were the most cited research in Earth, Atmospheric, and of Science Core Collection with the help of quantitative Planetary Sciences, totaling 340 citations. This review paper and qualitative research tools to map the characteristics of carefully examined the present significance of the effect of research output on the impact of COVID-19 social lock- air pollution in what looks like an unending COVID-19 pan- downs on air quality from 2020 to 2022. Several bibliomet- demic and social lockdown and future perceptions. Thus, ric evaluations were studied regarding the countries’ scien- this research gives experts data, proof, and knowledge of tific productivity, keywords analysis, and dominant authors. how COVID-19 social lockdowns affect air pollution, espe- Most of the articles were issued in journals like Atmosphere cially in metropolitan locations. (38, 7.54%), Science of the Total Environment (37, 7.31%), 1 3 Environmental Science and Pollution Research Amidst these contributions, the study is limited in the fol- Adam MG, Tran PTM, Balasubramanian R (2021) Air quality changes lowing ways. Over the years, there has been an underlying in cities during the COVID-19 lockdown: a critical review. Atmos problem with bibliometric methods. This approach usually Res 264:105823. https://d oi.o rg/1 0.1 016/j.a tmosr es.2 021.1 05823Afrane S, Ampah JD, Aboagye EM (2022a) Investigating evolutionary centers on the research outputs rather than content; however, trends and characteristics of renewable energy research in Africa: the researchers were able to capture contents as part of the a bibliometric analysis from 1999 to 2021. In: Environmental Sci- discussions for this study. Additionally, selection bias is pos- ence and Pollution Research (Issue 0123456789). Springer Berlin sible since the study documents were fundamentally based Heidelberg. https:// doi. org/ 10. 1007/ s11356- 022- 20125-0Afrane S, Ampah JD, Mensah EA (2022b) Visualization and analysis on the Web of Science Core Collection. Although the Web of mapping knowledge domains for the global transition towards of Science is broad and reliable, more sources like Scopus clean cooking: a bibliometric review of research output from 1990 and Google Scholar could present a more thorough concept to 2020. Environ Sci Pollut Res 29(16):23041–23068. https://d oi. and ideas. Nevertheless, if these limitations are solved, we org/ 10. 1007/ s11356- 021- 17340-6Agyepong LA, Liang X (2022) Mapping the knowledge frontiers of pub- do not expect a substantial difference from the findings of lic risk communication in disaster risk management. Journal of Risk the current review. Research:1–22. https:// doi. org/1 0. 1080/ 13669 877.2 022.2 12785 1 Alvarez CM, Hourcade R, Lefebvre B, Pilot E (2020) A scoping Abbreviations AIDS:  acquired immune deficiency syndrome; review on air quality monitoring, policy and health in west B.P: blood pressure; COPD: chronic obstructive pulmonary disease; african cities. Int J Environ Res Public Health 17(23):1–28. EPA: Environmental Protection Agency; HIV: human immune virus; https:// doi. org/ 10.3 390/i jerph 1723 9151 ICU: intensive care unit; IF: impact factor; MCP: multiple country Amnuaylojaroen T, Parasin N, Limsakul A (2022) Health risk publications; PM: particulate matter; SARS: severe acute respiratory assessment of exposure near-future PM2. 5 in Northern Thai- syndrome; SCP: single country publication; WHO: World Health land. Air Qual Atmos Health 15(11):1963–1979 Organization; WoS: Web of Science Arora S, Deoli K, Kumar P (2020) Coronavirus lockdown helped the environment to bounce back. Sci Total Environ Acknowledgments All authors thank the Zhongnan University of Eco- 742(1):140573. https:// doi. org/ 10. 1016/j. scito tenv. 2020. nomics and Law for all the computational resources. 140573 Ballester F, Medina S, Boldo E, Goodman P, Neuberger M, Iñiguez Author contribution Conceptualization: Emmanuel Mensah Aboagye; C, Künzli N (2008) Reducing ambient levels of fine particu- formal analysis: Emmanuel Mensah Aboagye and Nana Adwoa Anokye lates could substantially improve health: a mortality impact Effah; methodology: Emmanuel Mensah Aboagye; software: Emma- assessment for 26 European cities. J Epidemiol Community nuel Mensah Aboagye and Nana Adwoa Anokye Effah; supervision: Health 62(2):98–105. https:// doi. org/ 10. 1136/ jech. 2007. Kwaku Obeng Effah. 059857 Banks LM, Davey C, Shakespeare T, Kuper H (2020) Disability- Data availability Not applicable inclusive responses to COVID-19: lessons learnt from research on social protection in low- and middle-income countries. Declarations World Develop J 137(1):105178. http://c ommo ns.c larku. edu/ idce_m aste rs_ papers Ethics approval Not applicable Bao R, Zhang A (2020) Science of the total environment does lockdown reduce air pollution ? Evidence from 44 cities Consent to participate All authors agreed to contribute to this study. in northern China. Sci Total Environ 731:139052. https://d oi. org/1 0.1 016/j.s citot env.2 020. 139052 Consent for publication All authors agreed. Bar S, Parida BR, Mandal SP, Pandey AC, Kumar N, Mishra B (2021) Impacts of partial to complete COVID-19 lockdown on NO2 Competing interests The authors declare no competing interests. and PM2.5 levels in major urban cities of Europe and USA. Cit- ies 117(2):103308. https://d oi.o rg/1 0.1 016/j.c ities.2 021.1 03308 Bhatti UA, Zeeshan Z, Nizamani MM, Bazai S, Yu Z, Yuan L (2022) Assessing the change of ambient air quality patterns in Jiangsu province of China pre-to post-COVID-19. Chemos- References phere 288(P2):132569. https://d oi.o rg/1 0.1 016/j.c hemos phere. 2021. 132569 Aamir M, Li Z, Bazai S, Wagan RA, Bhatti UA, Nizamani MM, Akram Brandão LC, Soares de Mello JCCB (2019) A multi-criteria S (2021) Spatiotemporal change of air-quality patterns in Hubei approach to the h-index. Eur J Oper Res 276(1):357–363. province—a pre-to post-COVID-19 analysis using path analysis https://d oi. org/ 10.1 016/j. ejor.2 018. 12.0 33 and regression. Atmosphere 12(10):1–15. https://d oi.o rg/1 0.3 390/ Briz-redón Á, Belenguer-sapiña C, Serrano-aroca Á (2021) atmos 121013 38 Changes in air pollution during COVID-19 lockdown in Spain: Aboagye EM, Attobrah J, Effah NAA, Afrane S, Mensah F (2021) a multi-city study. J Environ Sci 101:16–26. https:// doi. org/ “Fortune amidst misfortune”: the impact of COVID-19 city lock- 10.1 016/j. jes. 2020. 07. 029 downs on air quality. Sustainable Environment 7(1):1885185. Casado-Aranda L-A, Juan Sanchez-Fernandez MIV-J (2021) Anal- https:// doi.o rg/ 10.1 080/ 276585 11. 2021.1 88518 5 ysis of the scientific production of the effect of COVID-19 Aboagye EM, Mensah F, Owusu NO, Effah KO, Erzuah M (2022) on the environment : a bibliometric study. Environ Res Disability inclusiveness in COVID-19 pandemic policies in 193(1):110414. https://d oi.o rg/1 0.1 016/j.e nvres.2 020.1 10416 West Africa: “are we left behind?”. Cogent Social Sciences Chakraborty I, Maity P (2020) COVID-19 outbreak: migration, 8(1):2079803. https:// doi. org/1 0.1 080/2 3311 886.2 022.2 07980 3 effects on society, global environment and prevention. Sci 1 3 Environmental Science and Pollution Research Total Environ 728(1):138882. https:// doi. org/ 10. 1016/j. scito Gautam S (2020) COVID-19: air pollution remains low as people tenv. 2020. 138882 stay at home. Air Qual Atmos Health 13(7):853–857. https:// Chattopadhyay A, Shaw S (2021) Association between air pol- doi.o rg/ 10.1 007/ s11869- 020-0 0842-6 lution and COVID-19 pandemic : an investigation in Hasnain A, Sheng Y, Hashmi MZ, Bhatti UA, Hussain A, Hameed Mumbai, India. Geohealth 5(7):1–16. https://d oi.o rg/1 0.1 029/ M, Marjan S, Bazai SU, Hossain MA, Sahabuddin M, Wagan 2021G H0003 83 RA, Zha Y (2022) Time series analysis and forecasting of Chen C (2006) CiteSpace II: detecting and visualizing emerging air pollutants based on prophet forecasting model in Jiangsu trends and transient patterns in scientific literature. J Am Soc province, China. Frontiers in Environmental Science 10:1–12. Inf Sci Technol 57(1):359–377 https://doi.org/10.1002/asi https:// doi. org/ 10.3 389/f envs.2 022. 945628 Chen C, Ibekwe-SanJuan F, Hou J (2010) The structure and dynam- He G, Pan Y, Tanaka T (2020) The short-term impacts of COVID- ics of cocitation clusters: a multiple-perspective cocitation 19 lockdown on urban air pollution in China. Nature Sus- analysis. J Am Soc Inf Sci Technol 61(1):1386–1409 https:// tainability 3(12):1005–1011. https:// doi. org/ 10. 1038/ doi.org/10.1002/asi s41893- 020- 0581-y Chen C, Dubin R, Kim MC (2014a) Emerging trends and new Hirsch J (2005) An index to quantify an individual’s scientific developments in regenerative medicine: a scientometric update research output. Proc Natl Acad Sci U S A 102(46):16569– (2000-2014). Expert Opin Biol Ther 14(9):1295–1317. https:// 16572. https://d oi. org/1 0. 1073/ pnas. 050765 5102 doi.o rg/1 0. 1517/ 14712 598.2 014. 920813 Huang C, Yang C, Wang S, Wu W, Su J, Liang C (2020) Evolution Chen C, Dubin R, Kim MC (2014b) Orphan drugs and rare dis- of topics in education research : a systematic review eases: a scientometric review (2000-2014). Expert Opinion on using bibliometric analysis. Educ Rev 72(3):281–297. https:// Orphan Drugs 2(7):709–724. https:// doi. org/ 10. 1517/ 21678 doi. org/1 0. 1080/ 00131 911. 2019. 15662 12 707. 2014. 920251 Isaifan RJ (2020) The dramatic impact of Coronavirus outbreak Cheval S, Adamescu CM, Georgiadis T, Herrnegger M, Piticar on air quality: has it saved as much as it has killed so far? A, Legates DR (2020) Observed and potential impacts of the Global Journal of Environmental Science and Management COVID-19 pandemic on the environment. Int J Environ Res 6(3):275–288. https:// doi. org/ 10. 22034/ gjesm.2 020. 03.0 1 Public Health 17(11):1–25. https://d oi.o rg/1 0.3 390/i jerph 1711 Jain S, Sharma T (2020) Social and travel lockdown impact con- 4140 sidering coronavirus disease ( COVID-19 ) on air quality in Dedoussi IC, Eastham SD, Monier E, Barrett SRH (2020) Prema- megacities of India: present benefits , future challenges and ture mortality related to United States cross-state air pollution. way forward. Aerosol Air Qual Res 20(1):1222–1236 Nature 578. https://d oi. org/1 0.1 038/ s41586- 020- 1983-8 Jin C, Ampah JD, Afrane S, Yin Z, Liu X, Sun T, Geng Z, Ikram Desouza PN, Oriama PA, Pedersen PP, Horstmann S, Gordillo- M, Liu H (2022) Low-carbon alcohol fuels for decarboniz- Dagallier L, Christensen CN, Franck CO, Ayah R, Kahn RA, ing the road transportation industry: a bibliometric analysis Klopp JM, Messier KP, Kinney PL (2021) Spatial variation 2000–2021. Environ Sci Pollut Res 29(4):5577–5604. https:// of fine particulate matter levels in Nairobi before and during doi.o rg/1 0.1 007/ s11356- 021-1 5539-1 the COVID-19 curfew: implications for environmental jus- Jin Y, Andersson H, Zhang S (2016) Air pollution control poli- tice. Environmental Research Communications 3(7). https:// cies in China: a retrospective and prospects. Int J Environ Res doi. org/1 0.1 088/ 2515-7 620/ ac1214 Public Health 13(12). https://d oi.o rg/1 0.3 390/i jerph 13121 219 Domingo L, Marqu M, Rovira J (2020) Influence of airborne trans- Jyoti K (2020) Science of the total environment substantial changes mission of SARS-CoV-2 on COVID-19 pandemic . a review. in PM 2. 5 pollution and corresponding premature deaths Environmental Research Journal 188:17–20. https:// doi. org/ across China during 2015 – 2019: A model prospective ☆. 10. 1016/j. envres.2 020.1 09861 Sci Total Environ 729:138838. https://d oi.o rg/1 0.1 016/j.s cito Dong X, Cao YY, Lu XX, Zhang JJ, Du H, Yan YQ, Akdis CA, Gao tenv. 2020. 138838 YD (2020) Eleven faces of coronavirus disease 2019. Allergy: Khan KI, Nasir A, Saleem S (2021) Bibliometric analysis of post European Journal of Allergy and Clinical Immunology. https:// COVID-19 management strategies and policies in hospitality doi. org/1 0. 1111/a ll.1 4289 and tourism. Front Psychol 12:1–14. https:// doi. org/ 10. 3389/ Ebisu K, Bell ML (2012) Airborne PM2.5 chemical components fpsyg. 2021.7 69760 and low birth weight in the northeastern and mid-Atlan- Liu Q, Harris JT, Chiu LS, Sun D, Houser PR, Yu M, Duffy tic regions of the United States. Environ Health Perspect DQ, Little MM, Yang C (2021a) Spatiotemporal impacts of 120(12):1746–1752. https:// doi.o rg/ 10. 1289/ ehp.1 1047 63 COVID-19 on air pollution in California, USA. Sci Total Envi- Effah NAA, Asiedu M, Otchere OAS (2022) Improvements or ron 750(1):141592. https:// doi. org/ 10. 1016/j. scito tenv. 2020. deteriorations? A bibliometric analysis of corporate govern- 141592 ance and disclosure research (1990–2020). Journal of Business Liu, W., Yang, Z., & Liu, Q. (2021b). Estimations of ambient fine and Socio-Economic Development. https:// doi. org/ 10. 1108/ particle and ozone level at a suburban site of Beijing in winter. jbsed- 10-2 021- 0142 Environmental Research Communications, 3(8), 0–11. https:// Filonchyk M, Peterson M (2020) Air quality changes in Shang- doi.o rg/ 10. 1088/2 515- 7620/a c1f82 hai, China, and the surrounding urban agglomeration dur- Ma X, Gao M, Gao Z, Wang J, Zhang M, Ma Y, Wang Q (2018) ing the COVID-19 lockdown. Journal of Geovisualization Past, current, and future research on microalga-derived bio- and Spatial Analysis 4(2):1–7. https:// doi. org/ 10. 1007/ diesel: a critical review and bibliometric analysis. Environ s41651- 020- 00064-5 Sci Pollut Res 25(11):10596–10610. https:// doi. org/1 0. 1007/ Filonchyk M, Hurynovich V, Yan H, Gusev A, Shpilevskaya N s11356-0 18- 1453-0 (2020) Impact assessment of COVID-19 on variations of Mao G, Zou H, Chen G, Du H, Zuo J (2015) Past, current and so2, no2, co and aod over east China. Aerosol Air Qual Res future of biomass energy research: a bibliometric analysis. 20(7):1530–1540. https:// doi. org/ 10.4 209/ aaqr.2 020. 05. 0226 Renew Sust Energ Rev 52:1823–1833. https:// doi. org/ 10. Fuwape IA, Okpalaonwuka CT, Ogunjo ST (2021) Impact of 1016/j.r ser. 2015. 07. 141 COVID -19 pandemic lockdown on distribution of inorganic Marinello S, Butturi MA, Gamberini R (2021) How changes in pollutants in selected cities of Nigeria. Air Qual Atmos Health human activities during the lockdown impacted air quality 14(2):149–155. https:// doi.o rg/ 10. 1007/ s11869- 020-0 0921-8 1 3 Environmental Science and Pollution Research parameters: a review. Environ Prog Sustain Energy 40(4):1– *. Environ Pollut 268:115859. https:// doi. org/ 10. 1016/j. 18. https:// doi.o rg/1 0.1 002/e p. 13672 envpol. 2020. 115859 Mehmood K, Mushtaq S, Bao Y, Sadia S, Muhammad B (2022) United Nations. (2020). Policy brief: a disability-inclusive response The impact of COVID - 19 pandemic on air pollution : to COVID-19. United Nation, 1–18. https://w ww.u n.o rg/s ites/ a global research framework , challenges , and future perspec- un2.u n. org/f iles/s g_ policy_ brief_ on_ person s_ with_ disabi liti tives. Environ Sci Pollut Res 29(1):52618–52634. https://d oi. es_ final.p df org/ 10. 1007/ s11356- 022- 19484-5 Venter AD, Louren ASM (2021) Ambient air quality data reported Muhammad S, Long X, Salman M (2020) COVID-19 pandemic at Sasol Secunda monitoring stations during COVID-19 lock- and environmental pollution: a blessing in disguise? Sci Total down -Mpumalanga, South Africa. Clean Air Journal 31(1):1– Environ 728:138820. https://d oi.o rg/1 0.1 016/j.s citot env.2 020. 7. https:// doi. org/1 0. 17159/ caj/ 2021/ 31/1. 8954 138820 Venter ZS, Aunan K, Chowdhury S, Lelieveld J (2020) COVID- Namdar-khojasteh D, Yeghaneh B, Maher A, Namdar-khojasteh 19 lockdowns cause global air pollution declines. EARTH, F (2022) Assessment of the relationship between exposure to ATMOSPHERIC, AND PLANETARY SCIENCES air pollutants and COVID-19 pandemic in Tehran city, Iran. 117(32):18984–18990. https:// doi. org/ 10. 1073/ pnas. 20068 Atmospheric Pollution Research 13(7):101474. https://d oi.o rg/ 53117 10. 1016/j. apr. 2022.1 01474 Wang M, Liu F, Zheng M (2021) Air quality improvement from Naqvi HR, Datta M, Mutreja G, Siddiqui MA, Naqvi DF, Naqvi AR COVID-19 lockdown : evidence from China. Air Qual Atmos (2021) Improved air quality and associated mortalities in India Health 14(2):591–604 under COVID-19 lockdown. Environ Pollut 268(2):115691. Xie M, Chen Q (2020) Insight into 2019 novel coronavirus — https://d oi.o rg/ 10. 1016/j.e nvpol. 2020. 115691 an updated interim review and lessons from SARS-CoV and Pei Z, Han G, Ma X, Su H, Gong W (2020) Response of major MERS-CoV. Int J Infect Dis 94:119–124. https:// doi. org/ 10. air pollutants to COVID-19 lockdowns in China. Sci Total 1016/j.i jid. 2020. 03.0 71 Environ 743:140879. https://d oi.o rg/1 0.1 016/j.s citot env.2 020. Yadav R, Korhale N, Anand V, Rathod A, Bano S, Shinde R, Latha 140879 R, Sahu SK, Murthy BS, Beig G (2020) COVID-19 lockdown Sathe Y, Gupta P, Bawase M, Lamsal L, Patadia F, Thipse S (2021) and air quality of SAFAR-India metro cities. Urban Clim Surface and satellite observations of air pollution in India dur- 34:100729. https://d oi.o rg/1 0. 1016/j. uclim. 2020.1 00729 ing COVID-19 lockdown: implication to air quality. Sustain Zangari S, Hill DT, Charette AT, Mirowsky JE (2020) Air quality Cities Soc 66(2):102688. https:// doi. org/ 10. 1016/j. scs. 2020. changes in New York City during the COVID-19 pandemic. 102688 Sci Total Environ 742:140496. https://d oi.o rg/1 0.1 016/j.s cito Schormans AF, Hutton S, Blake M, Earle K, Head KJ (2021) Social tenv. 2020. 140496 isolation continued: COVID-19 shines a light on what self- Zhang K, Liang QM (2020) Recent progress of cooperation on advocates know too well. Qual Soc Work 20(1–2):83–89. climate mitigation: a bibliometric analysis. J Clean Prod https:// doi.o rg/ 10. 1177/1 47332 50209 81755 277(5):123495. https://d oi.o rg/1 0.1 016/j.j clepr o.2 020.1 23495 Seo JH, Jeon HW, Sung UJ, Sohn J (2020) Impact of the COVID-19 Zhang J, Yu Z, Zhao B, Sun R, Vejre H (2020a) Links between outbreak on air quality in Korea. Atmosphere 2020(2):1–15 green space and public health : a bibliometric review of global Sicard P, De Marco A, Agathokleous E, Feng Z, Xu X, Paoletti E, research trends and future prospects from 1901 to 2019 Links Jaime J, Rodriguez D, Calatayud V (2020) Amplified ozone between green space and public health : a bibliometric review pollution in cities during the COVID-19 lockdown Pierre. Sci of global research trends and future prospects from 19. Envi- Total Environ 735:139542. https://d oi.o rg/1 0.1 016/j.s citot env. roenmental Research Letters 15:063001 2020. 139542 Zhang Q, Rong G, Meng Q, Yu M, Xie Q, Fang J (2020b) Outlining Smith SJ, Chateau J, Dorheim K, Drouet L, Durand-lasserve O, the keyword co-occurrence trends in Shuanghuanglian injec- Fricko O, Fujimori S, Hanaoka T (2020) Impact of methane tion research: a bibliometric study using CiteSpace III. Jour- and black carbon mitigation on forcing and temperature : a nal of Traditional Chinese Medical Sciences 7(2):189–198. multi-model scenario analysis. Clim Chang 163(1):1427–1442 https:// doi.o rg/1 0. 1016/j.j tcms. 2020. 05.0 06 Sulaymon ID, Zhang Y, Hopke PK, Hu J, Zhang Y, Li L, Mei X, Zoran MA, Savastru RS, Savastru DM, Tautan MN (2020) Assessing the Gong K, Shi Z, Zhao B, Zhao F (2021) Persistent high P M2.5 relationship between surface levels of PM2.5 and PM10 particu- pollution driven by unfavorable meteorological conditions late matter impact on COVID-19 in Milan, Italy. Sci Total Environ during the COVID-19 lockdown period in the Beijing-Tianjin- 738(1):139825. https:// doi. org/ 10. 1016/j.s cito tenv. 2020. 139825 Hebei region, China. Environ Res 198:111186. https://d oi.o rg/ 10. 1016/j. envres. 2021. 111186 Publisher’s note Springer Nature remains neutral with regard to Terpi M, Czwojdzi M (2021) ScienceDirect infection rates and jurisdictional claims in published maps and institutional affiliations. mortality : a one-year observational study in Poland. Biom J 44:25–36. https://d oi.o rg/ 10.1 016/j.b j. 2021. 11. 006 Springer Nature or its licensor (e.g. a society or other partner) holds Tohno S, Chatani S (2021) Consumption in the G20 nations causes exclusive rights to this article under a publishing agreement with the particulate air pollution resulting in two million premature author(s) or other rightsholder(s); author self-archiving of the accepted deaths annually. Nat Commun 12(1):1–6. https:// doi. org/ 10. manuscript version of this article is solely governed by the terms of 1038/ s41467- 021-2 6348-y such publishing agreement and applicable law. Travaglio M, Yu Y, Popovic R, Selley L, Leal NS, Martins LM (2021) Links between air pollution and COVID-19 in England 1 3