ABSTRACT
Micromobility can bring numerous benefits by providing solutions to the problem of first and last mile con-nectivity, while offering solutions to the social and economic disparities in terms of mobility. However, mobility in urban systems depends on actors, public and private institutions, and macro-level changes, which means that the use or non-use of micromobility can be influenced differently depending on the city. Therefore, through the use of the multi-level perspective and social-technical transition, and the application of Fuzzy-set qualitative comparative analysis (FsQCA) with the Two-Step Protocol and cluster analysis, this study aims to understand the combination of factors that promote the use or non-use of micromobility in a sample of 100 cities. The results obtained show that the use and non-use of micromobility services is explained by different configurations of conditions (2 and 6 respectively) and that the variables linked to the context (landscape and regime) are related to the emergence of an innovation (micromobility) in a given niche. Likewise, in relation to the different context it is not possible to extrapolate the recipes that explain the use of mobility solutions between the different continents, but it is possible to do so for the conditions that explain the non-use.
ABSTRACT
The COVID Pandemic since early 2019 has imposed significant effects on our life. In the retail and logistics sector, the large-scale national lockdown has drastically driven e-commerce sales because the e-marketplace has become the only sales channel. Whilst the pandemic has accelerated the shift towards a more digital world and led to an irreversible dependence on e-commerce retailing, the pressure is on retailers and logistics service providers to respond to the growing demand for immediate delivery in the e-commerce era. Given the integration of smart lockers into developing a more favourable environment which potentially makes immediate delivery more feasible, this paper introduces a novel, dynamic delivery strategy, namely Community Logistics Strategy (CLS), for formulating and updating the new delivery plan in real time as new delivery requests to smart lockers arrive. To shed light on the effect of dynamic order arrival towards delivery planning, the CLS attempts to update the delivery plan by taking new requests into account in real time. Simulation results reveal the superiority of the proposed strategy in managing e-commerce delivery requests, especially within megacities where consumers are highly dense in a compact geographical area.
ABSTRACT
Fluxes of nitrogen oxides (NOx=NO+NO2) and carbon dioxide (CO2) were measured using eddy covariance at the British Telecommunications (BT) Tower in central London during the coronavirus pandemic. Comparing fluxes to those measured in 2017 prior to the pandemic restrictions and the introduction of the Ultra-Low Emissions Zone (ULEZ) highlighted a 73 % reduction in NOx emissions between the two periods but only a 20 % reduction in CO2 emissions and a 32 % reduction in traffic load. Use of a footprint model and the London Atmospheric Emissions Inventory (LAEI) identified transport and heat and power generation to be the two dominant sources of NOx and CO2 but with significantly different relative contributions for each species. Application of external constraints on NOx and CO2 emissions allowed the reductions in the different sources to be untangled, identifying that transport NOx emissions had reduced by >73 % since 2017. This was attributed in part to the success of air quality policy in central London but crucially due to the substantial reduction in congestion that resulted from pandemic-reduced mobility. Spatial mapping of the fluxes suggests that central London was dominated by point source heat and power generation emissions during the period of reduced mobility. This will have important implications on future air quality policy for NO2 which, until now, has been primarily focused on the emissions from diesel exhausts.
ABSTRACT
Air pollution is among the highest contributors to mortality worldwide, especially in urban areas. During spring 2020, many countries enacted social distancing measures in order to slow down the ongoing COVID-19 pandemic. A particularly drastic measure, the "lockdown”, urged people to stay at home and thereby prevent new COVID-19 infections during the first (2020) and second wave (2021) of the pandemic. In turn, it also reduced traffic and industrial activities. But how much did these lockdown measures improve air quality in large cities, and are there differences in how air quality was affected? Here, we analyse data from two megacities: London as an example for Europe and Delhi as an example for Asia. We consider data during first and second-wave lockdowns and compare them to 2019 values. Overall, we find a reduction in almost all air pollutants with intriguing differences between the two cities except Delhi in 2021. In London, despite smaller average concentrations, we still observe high-pollutant states and an increased tendency towards extreme events (a higher kurtosis of the probability density during lockdown) during 2020 and low pollution levels during 2021. For Delhi, we observe a much stronger decrease in pollution concentrations, including high pollution states during 2020 and higher pollution levels in 2021. These results could help to design policies to improve long-term air quality in megacities.
ABSTRACT
In recent years, the proliferation of coronavirus disease has profoundly affected the world. The vitality of urban space is difficult to recover in the short term. Therefore, in the early stage of human-to-human transmission of the epidemic, we need to determine the potential urban agglomeration space as soon as possible, the timely find of hidden danger areas, and carry out spatial optimization to prevent the further spread of the epidemic. This becomes the urgent problem at the moment. Jinan is the capital city of Shandong Province, and the mega-city of China. The study is focused on the main urban area within the bypass. This study used spatial data methods such as spatial grammar and GIS technology. First, we analyzed the spatial topological properties of urban road network during the epidemic. Then, we carried out spatial autocorrelation analysis on the topological attributes to get the shape of urban spatial clustering layout during the epidemic. Finally, the thesis crawled through various types of infrastructure points-of-interest and conducted nuclear density analysis to get the dynamic trend of urban space in Jinan. The research results showed that there is significant space for agglomeration in the main urban area of Jinan. The areas with strong agglomeration are basically located in tourism areas, school areas, business areas, living circle areas of residential communities in Licheng and Lixia districts, transportation hub areas in Tianqiao District, and high-tech industrial areas in Lixia District. Topography, water body, greening, and parks could effectively reduce the concentration of human flow, and are important areas to relieve the potential abnormal epidemic. This study provided a new method for detecting epidemic prevention and control areas, optimizing urban space layout and formulating prevention and control strategies in the early stage of human-to-human epidemic transmission and lack of case surveillance data and control measures.
ABSTRACT
Shanghai, one of China's most important economic centres, imposed a citywide lockdown in April and May 2022 to contain a resurgence in cases of the coronavirus disease in 2019. Compared with the 2020 lockdown, the 2022 lockdown occurred in a warm season and lasted much longer, thereby serving as a relevant real-world test of the response of ambient ozone (O3) concentrations to emission reductions in a high-O3 season. In this study, we analysed surface observations of O3 and nitrogen dioxide (NO2) concentrations and satellite-retrieved tropospheric NO2 and formaldehyde (HCHO) column concentrations in the first 5 months of 2022 with comparisons to the year 2021. During the 2-month 2022 lockdown, the maximum daily 8 h average (MDA8) O3 concentrations at 1 or more of the city's 19 sites exceeded China's air quality standard of 160 µgm-3 21 times, with the highest value being 200 µgm-3. The city-average MDA8 O3 concentration increased by 13 % in April–May 2022 year-on-year, despite sharp declines in NO2 surface and column concentrations (both by 49 %) and a 19 % decrease in the HCHO column concentration. These results show that the reductions in O3 precursors and other pollutants during the 2022 lockdown did not prevent ground-level O3 pollution. An analysis of meteorological data indicates that there were only small changes in the meteorological conditions, and there was little transport of O3 from the high-O3 inland regions during the 2022 lockdown, neither of which can account for the increased and high concentrations of O3 that were observed during this period. The mean HCHO/NO2 ratio in April–May increased from 1.11 in 2021 to 1.68 in 2022, and the correlation between surface O3 and NO2 concentrations changed from negative in 2021 to positive in 2022. These results indicate that the high O3 concentrations in 2022 were mainly due to large reductions in the emissions of NOx and that the decrease in the concentrations of volatile organic compounds (VOCs) could not overcome the NO titration effect. During the 2022 lockdown, Shanghai's urban centre remained VOC-sensitive despite drastic reductions in road transportation (73 %–85 %) and industrial activities (∼60 %), whereas its semi-rural areas transitioned from VOC-limited to VOC–NOx-co-limited regimes. Our findings suggest that future emission reductions similar to those that occurred during the lockdown, such as those that will result from electrifying transportation, will not be sufficient to eliminate O3 pollution in urban areas of Shanghai and possibly other VOC-limited metropoles without the imposition of additional VOC controls or more substantial decreases in NOx emissions.
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Purpose In past years, the global supply chain has witnessed devastating effects of coronavirus (COVID-19) disease. However, the COVID-19 pandemic has renewed the interest of the Sustainable Supply Chain (SSC) stakeholders on sustainability. The stakeholders are now rethinking their business processes and strategy to make them sustainable. In this context, the relevant literature is required to support emerging markets to formulate sustainability-focussed strategies. The purpose of this study is to provide a comprehensive analysis of potential antecedents that leads towards sustainable development of freight transportation in emerging markets. Design/methodology/approach Initially, the antecedents of the Sustainable Freight Transport (SFT) system are derived from the literature survey followed by verification from the experts. Then, the potential antecedents are categorized under four (social, organizational, operational and environmental) broad categories. Afterwards, a Neutrosophic Analytic Network Process (N-ANP) method is employed to obtain the priority weights of the identified potential antecedents. Findings The paper identified and ranked 17 antecedents of the SFT system. According to the study's findings, the top three antecedents of SFT are "the presence of a multimodal transportation system," "circularity in SFT" and "traffic congestion management". The results from the study advocate the promotion of existing multi-modal transport facilities which is promising to achieve sustainability. The results suggested the adoption of the digital twin to manage the transport operations. Originality/value This study sheds light on how to achieve sustainability in the freight transportation system post-COVID era highlighting the potential antecedents. The study's findings will assist practitioners in developing SFT strategies in the face of such pandemics in future.
ABSTRACT
Latin America, as other regions in the world, imposed mobility restrictions to tackle the COVID-19 pandemic. Although recent research has analyzed the effect of mobility restrictions on air quality in several regions, a scarce literature explores the causal effects of the lockdowns in Latin America at a city scale whose results may guide local policymaking. This article, based on a quasi-experimental approach, estimates the causal short-term impacts of lockdowns on air quality considering the influence of forest fires on pollution in four megacities in Latin America (Bogotá, Mexico City, Santiago, and Sao Paulo). Results show that nitrogen oxides and carbon monoxide consistently declined (from 16% to 68%), nevertheless, fine particles rarely decreased across cities. Only Bogotá exhibited an overall reduction in fine particles (45% for PM2.5). Mexico City obtained the lowest reduction in pollutants, whereas Bogotá outperformed other cities in several pollutants. Evidence from mobility statistics supports the decrease in air pollution by a reduction in driving, transit use, and other mobility indicators.
ABSTRACT
Urban areas and industrial facilities, which concentrate the majority of human activity and industrial production, are major sources of air pollutants, with serious implications for human health and global climate. For most of these pollutants, emission inventories are often highly uncertain, especially in developing countries. Spaceborne measurements from the TROPOMI instrument, on board the Sentinel-5 Precursor satellite, are used to retrieve nitrogen dioxide (NO2) column densities at high spatial resolution. Here, we use 2 years of TROPOMI retrievals to map nitrogen oxide (NOx = NO + NO2) emissions in Egypt with a top-down approach using the continuity equation in steady state Emissions are expressed as the sum of a transport term and a sink term representing the three-body reaction comprising NO2 and hydroxyl radical (OH). This sink term requires information on the lifetime of NO2, which is calculated with the use of the CAMS near-real-time temperature and OH concentration fields. We compare this derived lifetime with the lifetime inferred from the fitting of NO2 line density profiles in large plumes with an exponentially modified Gaussian function. This comparison, which is conducted for different samples of NO2 patterns above the city of Riyadh, provides information on the reliability of the CAMS near-real-time OH concentration fields;it also provides some hint on the vertical levels that best represent typical pollution sources in industrial areas and megacities in the Middle East region. In Egypt, total emissions of NOx are dominated by the sink term, but they can be locally dominated by wind transport, especially along the Nile where human activities are concentrated. Megacities and industrial regions clearly appear as the largest sources of NOx emissions in the country. Our top-down model infers emissions with a marked annual variability. By looking at the spatial distribution of emissions at the scale of different cities with different industrial characteristics, it appears that this variability is consistent with national electricity consumption. We detect lower emissions on Fridays, which are inherent to the social norm of the country, and quantify the drop in emissions in 2020 due to the COVID-19 pandemic. Overall, our estimations of NOx emissions for Egypt are 7.0 % higher than the CAMS-GLOB-ANT_v4.2 inventory and significantly differ in terms of seasonality.
ABSTRACT
The aim of this paper is to highlight how TROPOspheric Monitoring Instrument (TROPOMI) trace gas data can best be used and interpreted to understand event-based impacts on air quality from regional to city scales around the globe. For this study, we present the observed changes in the atmospheric column amounts of five trace gases (NO2, SO2, CO, HCHO, and CHOCHO) detected by the Sentinel-5P TROPOMI instrument and driven by reductions in anthropogenic emissions due to COVID-19 lockdown measures in 2020. We report clear COVID-19-related decreases in TROPOMI NO2 column amounts on all continents. For megacities, reductions in column amounts of tropospheric NO2 range between 14 % and 63 %. For China and India, supported by NO2 observations, where the primary source of anthropogenic SO2 is coal-fired power generation, we were able to detect sector-specific emission changes using the SO2 data. For HCHO and CHOCHO, we consistently observe anthropogenic changes in 2-week-averaged column amounts over China and India during the early phases of the lockdown periods. That these variations over such a short timescale are detectable from space is due to the high resolution and improved sensitivity of the TROPOMI instrument. For CO, we observe a small reduction over China, which is in concert with the other trace gas reductions observed during lockdown;however, large interannual differences prevent firm conclusions from being drawn. The joint analysis of COVID-19-lockdown-driven reductions in satellite-observed trace gas column amounts using the latest operational and scientific retrieval techniques for five species concomitantly is unprecedented. However, the meteorologically and seasonally driven variability of the five trace gases does not allow for drawing fully quantitative conclusions on the reduction in anthropogenic emissions based on TROPOMI observations alone. We anticipate that in future the combined use of inverse modeling techniques with the high spatial resolution data from S5P/TROPOMI for all observed trace gases presented here will yield a significantly improved sector-specific, space-based analysis of the impact of COVID-19 lockdown measures as compared to other existing satellite observations. Such analyses will further enhance the scientific impact and societal relevance of the TROPOMI mission.
ABSTRACT
By utilizing the tourism development data of Beijing for the period from 2010 to 2019, this study examined the spatial pattern distribution of tourism development in Beijing using the coefficient of variation and Moran’s I index. In addition, the geographic detector method was employed to explore the impact of tourism resource investment, tourism reception facilities, and urban development level on the spatial pattern of tourism development. The results indicate that the spatial differences in tourism development in various Beijing districts are gradually expanding, mainly focusing on the differences between urban function expansion regions. The number of tourists shows a spatial distribution pattern including a core area, urban function expansion area, ecological conservation area, and new urban development area. The spatial correlation of tourism development increases gradually, and some parts show the spatial correlation form of low–high aggregation. Tourism resource investment, tourism reception facilities, and urban development level all play a significant role in promoting the spatial pattern of tourism development, among which the most obvious role is the interactive effect of tourism reception facilities, star-rated hotels, and openness. Therefore, to improve the development of Beijing’s tourism industry, the government needs to pay attention to the differences in the expansion of urban functions, the degree of contact between regions, the number of tourism reception facilities, and the level of regional openness. The significance of this research is in promoting spatial governance, coordinated development among regions, and the high-quality development of tourism in Beijing, and laying down a foundation for the introduction of spatial collaborative governance policies in other megacities in China.
ABSTRACT
Статья посвящена проблематике новых социальных и политических разделений, связанных с широким использованием жителями мегаполисов и администрациями городов информационно-коммуникационных технологий. Рассмотрены различные подходы к концептуализации цифровых разрывов и к исследованию их социально-политических последствий. Проанализированы основные измерения и уровни цифровых разрывов в контексте актуальных социально-политических процессов и трендов развития, в том числе в период пандемии COVID-19, описаны некоторые подходы к их преодолению в условиях современного мегаполиса. Выделены и охарактеризованы три главных уровня цифровых разрывов в современных обществах: 1) наличие материальной базы для использования цифровых технологий (технический уровень);2) навыки их использования у различных людей (социальный уровень);и 3) реальные возможности полноценного участия индивида в жизни современного "цифрового" общества и демократического участия в политических и социальных процессах, в том числе в реализации своих гражданских прав и свобод, в расширении социальных связей и отношений (политический уровень). Показано, что при сохранении и росте актуальности этих трех "традиционных" типов цифровых разрывов в условиях мегаполиса все большее значение приобретают такие их новые аспекты, как доступ к наборам больших данных, степень зависимости от автоматизированных систем принятия решений (алгоритмов) с использованием технологий искусственного интеллекта, а также цифровое отчуждение и разделение по отношению к онлайн-образованию. Выявлены некоторые социально-политические последствия цифровых разрывов и связанные с ними политические риски. Сделан вывод, что предпринимаемые меры по смягчению и уменьшению цифровых разрывов в современном мегаполисе носят пока что главным образом частичный и паллиативный характер, причем основное внимание уделяется улучшению материальной базы для использования цифровых технологий, а не преодолению более глубоких социально-политических причин и последствий цифровых разделений и разрывов. Показано, что политика сокращения цифрового неравенства и цифровых разрывов в современных мегаполисах играет особенно важную роль, поскольку в них сосредоточено наиболее политически активное население.Alternate :The article deals with the problems of new social and political divisions associated with the widespread use of information and communication technologies (ICT) by inhabitants of megacities and city administrations. The author considers different approaches to the conceptualization of "digital divides" and to the study of their socio-political consequences, analyzes the main dimensions and levels of digital divide in the context of current socio-political processes and development trends, including during the COVID-19 pandemic, and considers different approaches to overcome them in a modern megacity. Three main levels of digital divide in modern societies are identified and characterized: 1) the availability of the material basis for the use of digital technology (technical level);2) the skills for its use by different people (social level);and 3) the real opportunities for full participation of the individual in the life of a modern "digital" society and democratic participation in political and social processes, including the realization of their civil rights and freedoms, in expanding social connections and relations (political level). It is shown that while these three "traditional" types of digital gaps – inequalities in access to ICT, in the level of digital skills and in the possibility of full participation in the political life of modern digital society – remain and grow in importance in the megacity context, their new aspects, such as access to big data sets (Big Data), the degree of dependence on automated decision-making systems (algorithms) using artificial intelligence technologies, and digital exclusion and separation on the relational level are becoming increasingly important. Some socio-political implications of the new digital divide and the associated political risks are identified. It is concluded that the measures taken to mitigate and reduce the digital divide in the modern metropolis have so far been mostly partial and palliative, with a focus on improving the material basis for the use of digital technologies rather than on overcoming the deeper sociopolitical causes and consequences of digital divisions and gaps. It is shown that policies to reduce the digital divide and digital inequality in modern megacities are particularly important because megacities are home to the most politically active populations.
ABSTRACT
The changes in air quality were investigated in six megacities during the shutdown phases in 2020 and were compared to the same time periods in the previous 10 years (2010-2019) using the data of Modern-Era Retrospective Analysis and Research and Application, version 2 (MERRA-2). The concentrations of PM10 and PM2.5 were greatly reduced in all megacities during the lockdown in 2020 when compared to the same period in 2019 and in the previous ten years. The highest reduction in PM10 was recorded in Delhi, and Sao Paulo (21%, and 15% and by 27%, and 9%), when compared with the concentrations in 2019 and in the period 2010-2019, respectively. Similarly, levels of PM2.5 in Delhi, Sao Paulo, Beijing, and Mumbai decreased by 20%, 14%, 12%, and 10%, respectively in 2020 when compared to the last ten years. Results indicated that the lockdown is an effective mitigation measure to improve air quality. The MERRA-2 reanalysis dataset could be a vital tool in air quality studies in places with a lack of In-situ observations.
ABSTRACT
The COVID-19 epidemic fully reflects the importance of surveillance and early warning of infectious diseases, and also puts forward higher requirements for us to further improve epidemic surveillance to achieve early detection, early identification, early reporting and early disposal of various pathogens. In this paper, we reviewed the development of the integrated surveillance system for infectious diseases in Shanghai in recent years, illustrated the approach of integrated surveillance based on syndromes and events, and initially summarized the key results of the integrated surveillance, expanding the scope of surveillance, improving sensitivity and enhancing the capacity of the system. Moreover, considering the requirements regarding the public health system, we provide some thoughts and suggestions on further expanding of the integrated surveillance, continuously strengthening the integration of public health surveillance with clinical diagnosis and treatment, laboratory capacity development, and public health information technology.
ABSTRACT
The Chinese government recently proposed ammonia (NH3) emission reductions (but without a specific national target) as a strategic option to mitigate fine particulate matter (PM2.5) pollution. We combined a meta-analysis of nationwide measurements and air quality modeling to identify efficiency gains by striking a balance between controlling NH3 and acid gas (SO2 and NOx) emissions. We found that PM2.5 concentrations decreased from 2000 to 2019, but annual mean PM2.5 concentrations still exceeded 35 µg m-3 at 74 % of 1498 monitoring sites during 2015–2019. The concentration of PM2.5 and its components were significantly higher (16 %–195 %) on hazy days than on non-hazy days. Compared with mean values of other components, this difference was more significant for the secondary inorganic ions SO42-, NO3-, and NH4+ (average increase 98 %). While sulfate concentrations significantly decreased over this period, no significant change was observed for nitrate and ammonium concentrations. Model simulations indicate that the effectiveness of a 50 % NH3 emission reduction for controlling secondary inorganic aerosol (SIA) concentrations decreased from 2010 to 2017 in four megacity clusters of eastern China, simulated for the month of January under fixed meteorological conditions (2010). Although the effectiveness further declined in 2020 for simulations including the natural experiment of substantial reductions in acid gas emissions during the COVID-19 pandemic, the resulting reductions in SIA concentrations were on average 20.8 % lower than those in 2017. In addition, the reduction in SIA concentrations in 2017 was greater for 50 % acid gas reductions than for the 50 % NH3 emission reductions. Our findings indicate that persistent secondary inorganic aerosol pollution in China is limited by emissions of acid gases, while an additional control of NH3 emissions would become more important as reductions of SO2 and NOx emissions progress.
ABSTRACT
The COVID-19 pandemic imposes huge challenges on urban development with its impacts on reshaping cities. Saigon-Ho Chi Minh City (HCMC), Vietnam is a typical mega-city with high population density coping with urban infrastructural issues. As social distancing and restrictions on the use of public space have been the key measures to deal with the pandemic, the communal areas in HCMC have been affected from both social and urban design aspects. The paper aims to explore the impacts during and after the COVID-19 epidemic on the public space in HCMC with the case study of four apartment residences in four different districts. It is carried on with 400 surveys and in-depth interviews with the apartment managers. Then, the case of public space in HCMC will be discussed to have a specific look into the issues in the global context. The article argues that despite the consequences of the pandemic to public areas, citizens’ need for these types of city elements persists. Finally, it provides suggestions for reshaping post-pandemic public spaces in both societies’ perception and urban planning strategy.
ABSTRACT
Worldwide, the COVID‐19 pandemic has resulted in significant changes in activity patterns and travel behavior. Some of these changes are due to responses to governmental or personal measures for controlling the spread of the pandemic (e.g. partial lockdowns, remote education, or work). This paper examines changes in human mobility over 1 year period (from March 1st, 2020 to March 30th, 2020) in Istanbul, Turkey, a megacity in developing countries. The study period imposed three distinct waves, 1st wave (March-April), the second wave (Nov/202–Jan/2021), and 3rd wave (March/2021-still continue). The paper includes two parts. The first part is an analytical analysis for traveler mobility trends using data of public transit automatic fare collection system and traffic volume counting sensors along with Istanbul metropolitan. For the 1st wave, mobility changes have a V-shape trend for public transit riders and a smooth U-shape for reported vehicles by highway sensors. Despite the severity level of the COVID-19 pandemic and mobility restriction measures during 2nd wave, there was a smooth drop in mobility indicating a change in human reaction toward pandemic severity. The second part is investigating differences in individuals’ trip characteristics for before the COVID-19 pandemic and after one year of pandemic based on data collected from an online survey. Tends to shift to use personal vehicle for daily trips, indicate more effective decisions should be implemented next to staggered working hours and reductions transit capacity to encourage travelers for using the sustainable transportation system. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
ABSTRACT
One of the main contributors to air pollution is particulate matter (PMxy), which causes several Covid-19 related diseases such as respiratory problems and cardiovascular disorders. Therefore, the spatial and temporal trend analysis of particulate matter and the mass concentration of all aerosol particles <= 2.5 mu m in diameter (PM2.5) have become critical to control the risk factors of co-morbidity of a patient. Lockdown plays a significant role in reducing Covid-19 cases as well as air pollution, including particulate matter concentration. This study aims to analyse the effect of the lockdown on controlling air pollution in metropolitan cities in India through various statistical modelling approaches. Most research articles in the literature assume a linear relationship between responses and covariates and take independent and identically distributed error terms in the model, which may not be appropriate for analysing such air pollution data. In this study, a pattern analysis of PM2.5 daily emissions in different main activity zones during 2019 and 2020 was performed. The seasonal effect was also taken into account when measuring the lockdown effect. The PM2.5 values at the unobserved location were predicted using three popular spatial interpolation techniques: (i) inverse distance weight (IDW), (ii) ordinary kriging (OK), and (iii) random forest regression kriging (RFK), and their root mean square error (RMSE) was compared. Subsequently, the spatio-temporal intervention of lock down on air pollution was estimated using the difference-in-difference (DID) estimator. In winter, the transport zones, namely Anand Vihar and ITO airport, were the most affected regions. The northwestern part of Delhi is the most sensitive zone in terms of air pollution. Due to the lockdown, the weekly PM2.5 emission decreased by 62.15%, the mass concentration of all aerosol particles <= 10 mu m in diameter (PM10) decreased by 53.14%, and the air quality index (AQI) improved by 22.40%. A proposal is made to adopt corrective measures to maintain the air pollution index, taking into account the spatial and temporal variability in the responses.
ABSTRACT
Colgan began her tenure as a professor at the Faculty of Education at Queen's University, nearly one-quarter century ago, in 1998--a momentous year in many ways, certainly one that changed everything for mathematics education in Ontario, and for her, professionally. It seems only fitting that as they celebrate this special anniversary of the Gazette, to reflect on that impactful year. "Unprecedented" is the word of the first three years of this current decade because of the unparalleled societal, economic, and educational upheaval caused by the 2020-2022 COVID-19 pandemic. True, there have been changes to mathematics in Ontario during these angst-ridden years-specifically, revisions to content and attention to affect in the 2020 Grades 1-8 curriculum and the more significant destreamed Grade 9 mathematics program, rolled out for Sep 2021. Both were poorly timed: announced in late June of both school years for September implementation. And yet, as one who has been fortunate enough to have survived unscathed by the successive waves rolled in by virus variants, and, consequently the most recent curricular modifications to Ontario math programs, she still believes that no changes can compare to the magnitude of those mandated in 1998.
ABSTRACT
Many studies have been conducted to explore the characteristics of PM2.5 pollution events in Sichuan Basin, China. However, they focused on either specific regional pollution events from different aspects or the megacities, such as Chengdu and Chongqing. To provide a panorama gram of PM2.5 pollution episodes in the whole basin area, we identified all the PM2.5 pollution events in 17 cities during 2016-2019 and analyzed the characteristics of these events. In total, 1342 episodes were identified and the characteristics of episode numbers, durations and PM2.5 concentrations were analyzed in each city. We found that the characteristics of the temporal and spatial distribution of the episode numbers and durations were similar to the annual average of PM2.5 concentrations, which were higher in the Southern Sichuan and Western Sichuan Plain spatially and occurred most frequently in winter, followed by spring, autumn and summer. Non-monotonical relationships were obtained between the PM2.5 concentrations and pollution durations and there was a duration threshold in each city. For episodes with durations shorter than the threshold, their PM2.5 concentrations increased with duration. The duration thresholds were 6–8 days and 5–7 days in Southern Sichuan and Western Sichuan Plain, respectively. We also found that the air quality deteriorated in 2019 in most cities. Synthetically considering the numbers, durations and concentrations of pollution episodes, more concerns should be taken for the prevention of PM2.5 pollution in Yibin in the Southern Sichuan, Chengdu and Leshan in the Western Sichuan Plain, Neijiang in the Central Hills, and Bazhong, Dazhou, Nanchong in the Northeastern Sichuan. These results could help understanding the characteristics of PM2.5 episodes in Sichuan Basin and providing implications for pollution control strategies in future.