To control the spread of COVID-19,rigorous restrictions have been implemented in China,resulting in a great reduction in pollutant emissions.In this study,we evaluated the air quality in the Yangtze River Delta during...To control the spread of COVID-19,rigorous restrictions have been implemented in China,resulting in a great reduction in pollutant emissions.In this study,we evaluated the air quality in the Yangtze River Delta during the COVID-19 lockdown period using satellite and ground-based data,including particle matter(PM),trace gases,water-soluble ions(WSIs) and black carbon(BC).We found that the impacts of lockdown policy on air quality cannot be accurately assessed using MODIS aerosol optical depth(AOD) data,whereas the tropospheric nitrogen dioxide(NO_(2)) vertical column density can well reflect the influences of these restrictions on human activities.Compared to the pre-COVID period,the PM_(2.5),PM_(10),NO_(2),carbon monoxide(CO),BC and WSIs during the lockdown in Suzhou were observed to decrease by 37.2%,38.3%,64.5%,26.1%,53.3% and 58.6%,respectively,while the sulfur dioxide(SO_(2)) and ozone(O_(3)) increased by 1.5% and 104.7%.The WSIs ranked in the order of NO_(3)~->NH_(4)^(+)>SO_(4)^(2-)>Cl~->Ca^(2+)>K^(+)>Mg^(2+)>Na + during the lockdown period.By comparisons with the ion concentrations during the pre-COVID period,we found that the ions NO 3-,NH 4 +,SO_(4)^(2-),Cl~-,Ca^(2+),K^(+) and Na^(+) decreased by 66.3%,48.8%,52.9%,56.9%,57.9% and 76.3%,respectively,during the lockdown,in contrast to Mg^(2+),which increased by 30.2%.The lockdown policy was found to have great impacts on the diurnal variations of Cl~-,SO_(4)^(2-),Na^(+) and Ca^(2+).展开更多
Background:During the COVID-19 pandemic,many countries used lockdowns as a containment measure.While lockdowns successfully contributed to slowing down the contagion,the related mobility restrictions were reportedly a...Background:During the COVID-19 pandemic,many countries used lockdowns as a containment measure.While lockdowns successfully contributed to slowing down the contagion,the related mobility restrictions were reportedly associated with an increased risk of major depressive and anxiety disorders.We aimed to quantify the trade-off between the quality-adjusted life years(QALY)gain due to lower COVID-19 incidence as a result of a lockdown and QALY loss due to lockdown-induced mental disorders.Methods:We developed an agent-based model of COVID-19 epidemic and coupled mental disorder development in the population of a large city.We used data sources on the places of living,studying and working,public health and census surveys.Modeling of mental disorders was based on diathesis-stress concept.We quantified mental and physical health burden in terms of QALY taking into account major depressive and anxiety disorder episodes,lethal and non-lethal cases of COVID-19,and immunization.Findings:We evaluated the dynamics of new major depressive disorder(MDD)and anxiety disorder(AD)cases during the period between September 2020 and December 2021 in Moscow,Russia.We found that lockdown imposition increases the daily chances of getting MDD or ADD by a vulnerable person by 16.79%(95%CI[12.36%,21.23%]).The QALY loss associated with COVID-19-induced and lockdown-induced mental disorders was estimated to be 18.93%(95%CI[16.94%,19.73%])of the total QALY loss caused by COVID-19,immunization,and all kinds of mental disorders.For a synthetic“strong”lockdown,it had been shown that QALY loss is minimized when about 70%of the population are isolated.Interpretation:The burden associated with mental disorders amounts to a considerable part of COVID-19-related losses.Our findings demonstrate that cost-benefit analysis of mobility restriction should include a forecast of mental disorder development in the population.展开更多
In the case of major public emergencies, the ability of cities to resist shocks becomes very important and reflects urban resilience. This paper selected the supply guarantee facilities during the city-wide lockdown o...In the case of major public emergencies, the ability of cities to resist shocks becomes very important and reflects urban resilience. This paper selected the supply guarantee facilities during the city-wide lockdown of Shanghai during March-May 2022 due to COVID-19 pandemic as the research object. In this research, the per capita supply guarantee capacity and supply guarantee overlay intensity were analyzed based on the official list of facilities, and the actual role of the supply guarantee facilities was investigated through a public research questionnaire. The thermodynamic diagram map that was generated based on phone visits reflected the actual distribution of the population. Then the level of “supply guarantee resilience” was evaluated and graded for each district of Shanghai. It was concluded that the overall level of supply guarantee resilience was high in the central city, divergence in the near suburban districts, and generally low in the remote suburban districts. Based on this, the paper summarized the problems of supply guarantee revealed in Shanghai during the epidemic lockdown as well as proposed strategies to improve the resilience of similar scenarios in the future. With the help of big data and public research tools, this paper aimed to provide ways and methods to evaluate the resilience of cities under major public emergencies.展开更多
The temporal variation of greenhouse gas concentrations in China during the COVID-19 lockdown in China is analyzed in this work using high resolution measurements of near surface ΔCO_(2),ΔCH_(4) andΔCO concentratio...The temporal variation of greenhouse gas concentrations in China during the COVID-19 lockdown in China is analyzed in this work using high resolution measurements of near surface ΔCO_(2),ΔCH_(4) andΔCO concentrations above the background conditions at Lin’an station(LAN),a regional background station in the Yangtze River Delta region.During the pre-lockdown observational period(IOP-1),bothΔCO_(2) andΔCH_(4) exhibited a significant increasing trend relative to the 2011-2019 climatological mean.The reduction ofΔCO_(2),ΔCH_(4) andΔCO during the lockdown observational period(IOP-2)(which also coincided with the Chinese New Year Holiday)reached up to 15.0 ppm,14.2 ppb and 146.8 ppb,respectively,and a reduction ofΔCO_(2)/ΔCO probably due to a dramatic reduction from industrial emissions.ΔCO_(2),ΔCH_(4) and ΔCO were observed to keep declining during the post-lockdown easing phase(IOP-3),which is the synthetic result of lower than normal CO_(2) emissions from rural regions around LAN coupled with strong uptake of the terrestrial ecosystem.Interestingly,the trend reversed to gradual increase for all species during the later easing phase(IOP-4),with ΔCO_(2)/ΔCO constantly increasing from IOP-2 to IOP-3 and finally IOP-4,consistent with recovery in industrial emissions associated with the staged resumption of economic activity.On average,ΔCO_(2) declined sharply throughout the days during IOP-2 but increased gradually throughout the days during IOP-4.The findings showcase the significant role of emission reduction in accounting for the dramatic changes in measured atmosphericΔCO_(2) and ΔCH_(4) associated with the COVID-19 lockdown and recovery.展开更多
The outbreak of COVID-19 has caused concerns globally.To reduce the rapid transmission of the virus,strict city lockdown measures were conducted in different regions.China is the country that takes the earliest home-b...The outbreak of COVID-19 has caused concerns globally.To reduce the rapid transmission of the virus,strict city lockdown measures were conducted in different regions.China is the country that takes the earliest home-based quarantine for people.Although normal industrial and social activities were suspended,the spread of virus was efficiently controlled.Simultaneously,another merit of the city lockdown measure was noticed,which is the improvement of the air quality.Contamination levels of multiple atmospheric pollutants were decreased.However,in this work,24 and 14 air fine particulate matter(PM_(2.5))samples were continuously collected before and during COVID-19 city lockdown in Linfen(a typical heavy industrial city in China),and intriguingly,the unreduced concentration was found for environmentally persistent free radicals(EPFRs)in PM_(2.5)after normal life suspension.The primary non-stopped coal combustion source and secondary Cu-related atmospheric reaction may have impacts on this phenomenon.The cigarette-based assessment model also indicated possible exposure risks of PM_(2.5)-bound EPFRs during lockdown of Linfen.This study revealed not all the contaminants in the atmosphere had an apparent concentration decrease during city lockdown,suggesting the pollutants with complicated sources and formation mechanisms,like EPFRs in PM_(2.5),still should not be ignored.展开更多
The coronavirus(COVID-19)pandemic is disrupting the world from many aspects.In this study,the impact of emission variations on PM_(2.5)-bound elemental species and health risks associated to inhalation exposure has be...The coronavirus(COVID-19)pandemic is disrupting the world from many aspects.In this study,the impact of emission variations on PM_(2.5)-bound elemental species and health risks associated to inhalation exposure has been analyzed based on real-time measurements at a remote coastal site in Shanghai during the pandemic.Most trace elemental species decreased significantly and displayed almost no diel peaks during the lockdown.After the lockdown,they rebounded rapidly,of which V and Ni even exceeded the levels before the lockdown,suggesting the recovery of both inland and shipping activities.Five sources were identified based on receptor modeling.Coal combustion accounted for more than 70%of the measured elemental concentrations before and during the lockdown.Shipping emissions,fugitive/mineral dust,and waste incineration all showed elevated contributions after the lockdown.The total non-carcinogenic risk(HQ)for the target elements exceeded the risk threshold for both children and adults with chloride as the predominant species contributing to HQ.Whereas,the total carcinogenic risk(TR)for adults was above the acceptable level and much higher than that for children.Waste incineration was the largest contributor to HQ,while manufacture processing and coal combustion were the main sources of TR.Lockdown control measures were beneficial for lowering the carcinogenic risk while unexpectedly increased the non-carcinogenic risk.From the perspective of health effects,priorities of control measures should be given to waste incineration,manufacture processing,and coal combustion.A balanced way should be reached between both lowering the levels of air pollutants and their health risks.展开更多
The higher concentration of PM_(10) and PM_(2.5) in the lower atmosphere is severely harmful for human health and it also makes visibility diminution along with weather and climate modifications.The main objective is ...The higher concentration of PM_(10) and PM_(2.5) in the lower atmosphere is severely harmful for human health and it also makes visibility diminution along with weather and climate modifications.The main objective is to find out the spatiotemporal variation and dispersal of PM_(10) and PM_(2.5) along with COVID-19 infection in the dusty city Kolkata.The consecutive two years PM_(10) and PM_(2.5) data of different stations have been obtained from State Pollution Control Board,Govt.of West Bengal.Forward trajectory analysis has been done through HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory)model to find the path and direction of air particles.The result showed that the various meteorological or environmental factors(such as temperature,relative humidity,wind,wind speed,pressure and gusty wind)and geographical location regulate the spatiotemporal variation of PM_(10) and PM_(2.5).These factors like high temperature with relative humidity and strong wind influence to disperse the particulate matters from north to south direction from city to outside during summer in Kolkata metropolitan city.During summer(both pre and lockdown years),the height of particles is extended up to 1000 m owing to active atmospheric ventilation whereas in winter it is confined within 100 m.The HYSPLIT model clearly specified that the particles dispersed from south,south-west to north and north east direction due to strong wind.The constant magnification of PM_(10) and PM_(2.5) in the lower atmosphere leads to greater frequency of COVID-19 infections and deaths.In Kolkata,the one of the crucial reasons of high infection and deaths(COVID-19)is co-morbidity of people.展开更多
Under the effects of COVID-19 and a number of ongoing lockdown tactics,anxiety symptoms and poor sleep quality have become common mental health issues among college freshmen and are intimately related to their emotion...Under the effects of COVID-19 and a number of ongoing lockdown tactics,anxiety symptoms and poor sleep quality have become common mental health issues among college freshmen and are intimately related to their emotional adaptation.To explore this connection,this study gathered data from a sample of 256 freshmen enrolled in an elite university in China in September 2022.The association between sleep quality,anxiety symptoms,and emotional adaptation was clarified using correlation analysis.Additionally,the mediating function of anxiety symptoms between sleep quality and emotional adaptation was investigated using a structural equation model.The results reveal that:(1)Chinese elite university freshmen who were subjected to prolonged lockdown had poor sleep quality and mild anxiety symptoms;(2)a significant positive correlation between poor sleep quality and anxiety symptoms was identified;(3)anxiety symptoms were found to have a significant negative impact on emotional adaptation;(4)poor sleep quality had a negative impact on emotional adaptation through anxiety symptoms.This research makes a valuable contribution by offering insights into the intricate relationship between sleep quality and emotional adaptation among freshmen in elite Chinese universities during prolonged lockdown conditions,and it is beneficial for schools and educators to further improve school schedules and psychological health initiatives.展开更多
Recently,air pollution especially fine particulate matters(PM_(2.5))and ozone(O_(3))has become a severe issue in China.In this study,we first characterized the temporal trends of PM_(2.5) and O_(3) for Beijing,Guangzh...Recently,air pollution especially fine particulate matters(PM_(2.5))and ozone(O_(3))has become a severe issue in China.In this study,we first characterized the temporal trends of PM_(2.5) and O_(3) for Beijing,Guangzhou,Shanghai,andWuhan respectively during 2018-2020.The annual mean PM2.5 has decreased by 7.82%-33.92%,while O_(3) concentration showed insignificant variations by-6.77%-4.65%during 2018-2020.The generalized additive models(GAMs)were implemented to quantify the contribution of individual meteorological factors and their gas precursors on PM_(2.5) and O_(3).On a short-term perspective,GAMs modeling shows that the daily variability of PM_(2.5) concentration is largely related to the variation of precursor gases(R=0.67-0.90),while meteorological conditions mainly affect the daily variability of O_(3) concentration(R=0.65-0.80)during 2018-2020.The impact of COVID-19 lockdown on PM_(2.5) and O_(3) concentrations were also quantified by using GAMs.During the 2020 lockdown,PM_(2.5) decreased significantly for these megacities,yet the ozone concentration showed an increasing trend compared to 2019.The GAMs analysis indicated that the contribution of precursor gases to PM_(2.5) and O_(3) changes is 3-8 times higher than that of meteorological factors.In general,GAMsmodeling on air quality is helpful to the understanding and control of PM2.5 and O3 pollution in China.展开更多
Organic aerosol(OA)is a major component of atmospheric particulate matter(PM)with complex composition and formation processes influenced by various factors.Emission reduction can alter both precursors and oxidants whi...Organic aerosol(OA)is a major component of atmospheric particulate matter(PM)with complex composition and formation processes influenced by various factors.Emission reduction can alter both precursors and oxidants which further affects secondary OA formation.Here we provide an observational analysis of secondary OA(SOA)variation properties in Yangtze River Delta(YRD)of eastern China in response to large scale of emission reduction during Chinese New Year(CNY)holidays from 2015 to 2020,and the COVID-19 pandemic period from January to March,2020.We found a 17%increase of SOA proportion during the COVID lockdown.The relative enrichment of SOA is also found during multi-year CNY holidays with dramatic reduction of anthropogenic emissions.Two types of oxygenated OA(OOA)influenced by mixed emissions and SOA formation were found to be the dominant components during the lockdown in YRD region.Our results highlight that these emission-reduction-induced changes in organic aerosol need to be considered in the future to optimize air pollution control measures.展开更多
The explosive spread of the 2019 novel coronavirus(COVID-19)provides a unique chance to rethink the relationship between human activity and air pollution.Though related studies have revealed substantial reductions in ...The explosive spread of the 2019 novel coronavirus(COVID-19)provides a unique chance to rethink the relationship between human activity and air pollution.Though related studies have revealed substantial reductions in primary emissions,obvious differences do exist in the responses of secondary pollutants,like ozone(0_(3))pollution.However,the regional disparities of O_(3)responses and their causes have still not been fully investigated.To better elucidate the interrelationship between anthropogenic emissions,chemical production,and meteorological conditions,O_(3)responses caused by lockdowns over different regions were comprehensively explored at a global scale.Observational signals of air-quality change were derived from multi-year surface measurements and satellite retrievals.With similar substantial drops in nitrogen dioxide(NO_(2)),ozone shows rising signals in most areas of both East Asia and Europe,even up to~14 ppb,while a non-negligible declining signal exists in North America,by about 2-4 ppb.Furthermore,the drivers behind the different O_(3)responses are discussed based on meteorological analysis and O_(3)sensitivity diagnosis.On the one hand,O_(3)responses to NO_(2)declines can be affected by the primary dependence on its precursors.On the other hand,it is also highly dependent on meteorological factors,especially temperature.Our study further highlights the great importance of taking into consideration both the regional disparities and synergistic effects of precursor reductions and meteorological influence for scientific mitigation of O_(3)pollution.展开更多
Estimating the impacts on PM_(2.5)pollution and CO_(2)emissions by human activities in different urban regions is important for developing efficient policies.In early 2020,China implemented a lockdown policy to contai...Estimating the impacts on PM_(2.5)pollution and CO_(2)emissions by human activities in different urban regions is important for developing efficient policies.In early 2020,China implemented a lockdown policy to contain the spread of COVID-19,resulting in a significant reduction of human activities.This event presents a convenient opportunity to study the impact of human activities in the transportation and industrial sectors on air pollution.Here,we investigate the variations in air quality attributed to the COVID-19 lockdown policy in the megacities of China by combining in-situ environmental and meteorological datasets,the Suomi-NPP/VIIRS and the CO_(2)emissions from the Carbon Monitor project.Our study shows that PM_(2.5)concentrations in the spring of 2020 decreased by 41.87%in the Yangtze River Delta(YRD)and 43.30%in the Pearl River Delta(PRD),respectively,owing to the significant shutdown of traffic and manufacturing industries.However,PM_(2.5)concentrations in the Beijing-Tianjin-Hebei(BTH)region only decreased by 2.01%because the energy and steel industries were not fully paused.In addition,unfavorable weather conditions contributed to further increases in the PM_(2.5)concentration.Furthermore,CO_(2)concentrations were not significantly affected in China during the short-term emission reduction,despite a 19.52%reduction in CO_(2)emissions compared to the same period in 2019.Our results suggest that concerted efforts from different emission sectors and effective long-term emission reduction strategies are necessary to control air pollution and CO_(2)emissions.展开更多
In this paper,we study how China’s stock market reacts to the sudden outbreak of COVID-19 in 2020,particularly to the announcement of the pandemic lockdown.In general,we observe reversals both at the industry level a...In this paper,we study how China’s stock market reacts to the sudden outbreak of COVID-19 in 2020,particularly to the announcement of the pandemic lockdown.In general,we observe reversals both at the industry level and at the firm level due to investors’overreactions to the pandemic lockdown.For industryand firm-level stocks with positive cumulative abnormal returns(CARs)in the event window when Wuhan was locked down,the reversals are stronger.Thus,the reversal effects are mostly driven by industries and stocks that positively overreact to COVID-19 than do others.Further investigation shows that overreactions are stronger for stocks with lower institutional ownership,which means that retail investors react more strongly to COVID-19.Among stocks with positive CARs in the event window,those with higher idiosyncratic volatilities and lower book-to-market ratios tend to have worse performance after one month.展开更多
Background:Several countries used varied degrees of social isolation measures in response to the COVID-19 outbreak.In 2021,the lockdown in Thailand began on July 20 and lasted for the following six weeks.The lockdown ...Background:Several countries used varied degrees of social isolation measures in response to the COVID-19 outbreak.In 2021,the lockdown in Thailand began on July 20 and lasted for the following six weeks.The lockdown has extremely detrimental effects on the economy and society,even though it may reduce the number of COVID-19 instances.Our goals are to assess the impact of the lockdown policy,the commencement time of lockdown,and the vaccination rate on the number of COVID-19 cases in Thailand in 2021.Methods:We modeled the dynamics of COVID-19 in Thailand throughout 2021 using the SEIR model.The Google Mobility Index,vaccine distribution rate,and lockdown were added to the model.The Google Mobility Index represents the movement of individuals during a pandemic and shows how people react to lockdown.The model also examines the effect of vaccination rate on the incidence of COVID-19.Results:The modeling approach demonstrates that a 6-week lockdown decreases the incidence number of COVID-19 by approximately 15.49e18.17%,depending on the timing of the lockdown compared to a non-lockdown scenario.An increasing vaccination rate potentially reduce the incidence number of COVID-19 by 5.12e18.35%without launching a lockdown.Conclusion:Lockdowns can be an effective method to slow down the spread of COVID-19 when the vaccination program is not fully functional.When the vaccines are easily accessible on a large scale,the lockdown may terminated.展开更多
基金supported by the National Natural Science Foundation of China (Nos.91644224,41805096)the National Key Research and Development Program of China (No.2016YFA0602003)+1 种基金the China Postdoctoral Science Foundation (No.2018M640169)the Natural Science Research Project for Universities of Jiangsu Province,China (No.18KJB170011)。
文摘To control the spread of COVID-19,rigorous restrictions have been implemented in China,resulting in a great reduction in pollutant emissions.In this study,we evaluated the air quality in the Yangtze River Delta during the COVID-19 lockdown period using satellite and ground-based data,including particle matter(PM),trace gases,water-soluble ions(WSIs) and black carbon(BC).We found that the impacts of lockdown policy on air quality cannot be accurately assessed using MODIS aerosol optical depth(AOD) data,whereas the tropospheric nitrogen dioxide(NO_(2)) vertical column density can well reflect the influences of these restrictions on human activities.Compared to the pre-COVID period,the PM_(2.5),PM_(10),NO_(2),carbon monoxide(CO),BC and WSIs during the lockdown in Suzhou were observed to decrease by 37.2%,38.3%,64.5%,26.1%,53.3% and 58.6%,respectively,while the sulfur dioxide(SO_(2)) and ozone(O_(3)) increased by 1.5% and 104.7%.The WSIs ranked in the order of NO_(3)~->NH_(4)^(+)>SO_(4)^(2-)>Cl~->Ca^(2+)>K^(+)>Mg^(2+)>Na + during the lockdown period.By comparisons with the ion concentrations during the pre-COVID period,we found that the ions NO 3-,NH 4 +,SO_(4)^(2-),Cl~-,Ca^(2+),K^(+) and Na^(+) decreased by 66.3%,48.8%,52.9%,56.9%,57.9% and 76.3%,respectively,during the lockdown,in contrast to Mg^(2+),which increased by 30.2%.The lockdown policy was found to have great impacts on the diurnal variations of Cl~-,SO_(4)^(2-),Na^(+) and Ca^(2+).
基金supported by the Ministry of Education and Science of Russia:Grant No.075-11-2020-011(13.1902.21.0040).
文摘Background:During the COVID-19 pandemic,many countries used lockdowns as a containment measure.While lockdowns successfully contributed to slowing down the contagion,the related mobility restrictions were reportedly associated with an increased risk of major depressive and anxiety disorders.We aimed to quantify the trade-off between the quality-adjusted life years(QALY)gain due to lower COVID-19 incidence as a result of a lockdown and QALY loss due to lockdown-induced mental disorders.Methods:We developed an agent-based model of COVID-19 epidemic and coupled mental disorder development in the population of a large city.We used data sources on the places of living,studying and working,public health and census surveys.Modeling of mental disorders was based on diathesis-stress concept.We quantified mental and physical health burden in terms of QALY taking into account major depressive and anxiety disorder episodes,lethal and non-lethal cases of COVID-19,and immunization.Findings:We evaluated the dynamics of new major depressive disorder(MDD)and anxiety disorder(AD)cases during the period between September 2020 and December 2021 in Moscow,Russia.We found that lockdown imposition increases the daily chances of getting MDD or ADD by a vulnerable person by 16.79%(95%CI[12.36%,21.23%]).The QALY loss associated with COVID-19-induced and lockdown-induced mental disorders was estimated to be 18.93%(95%CI[16.94%,19.73%])of the total QALY loss caused by COVID-19,immunization,and all kinds of mental disorders.For a synthetic“strong”lockdown,it had been shown that QALY loss is minimized when about 70%of the population are isolated.Interpretation:The burden associated with mental disorders amounts to a considerable part of COVID-19-related losses.Our findings demonstrate that cost-benefit analysis of mobility restriction should include a forecast of mental disorder development in the population.
文摘In the case of major public emergencies, the ability of cities to resist shocks becomes very important and reflects urban resilience. This paper selected the supply guarantee facilities during the city-wide lockdown of Shanghai during March-May 2022 due to COVID-19 pandemic as the research object. In this research, the per capita supply guarantee capacity and supply guarantee overlay intensity were analyzed based on the official list of facilities, and the actual role of the supply guarantee facilities was investigated through a public research questionnaire. The thermodynamic diagram map that was generated based on phone visits reflected the actual distribution of the population. Then the level of “supply guarantee resilience” was evaluated and graded for each district of Shanghai. It was concluded that the overall level of supply guarantee resilience was high in the central city, divergence in the near suburban districts, and generally low in the remote suburban districts. Based on this, the paper summarized the problems of supply guarantee revealed in Shanghai during the epidemic lockdown as well as proposed strategies to improve the resilience of similar scenarios in the future. With the help of big data and public research tools, this paper aimed to provide ways and methods to evaluate the resilience of cities under major public emergencies.
基金supported by the National Nature Science Foundation of China(Nos.41730103,41805129)
文摘The temporal variation of greenhouse gas concentrations in China during the COVID-19 lockdown in China is analyzed in this work using high resolution measurements of near surface ΔCO_(2),ΔCH_(4) andΔCO concentrations above the background conditions at Lin’an station(LAN),a regional background station in the Yangtze River Delta region.During the pre-lockdown observational period(IOP-1),bothΔCO_(2) andΔCH_(4) exhibited a significant increasing trend relative to the 2011-2019 climatological mean.The reduction ofΔCO_(2),ΔCH_(4) andΔCO during the lockdown observational period(IOP-2)(which also coincided with the Chinese New Year Holiday)reached up to 15.0 ppm,14.2 ppb and 146.8 ppb,respectively,and a reduction ofΔCO_(2)/ΔCO probably due to a dramatic reduction from industrial emissions.ΔCO_(2),ΔCH_(4) and ΔCO were observed to keep declining during the post-lockdown easing phase(IOP-3),which is the synthetic result of lower than normal CO_(2) emissions from rural regions around LAN coupled with strong uptake of the terrestrial ecosystem.Interestingly,the trend reversed to gradual increase for all species during the later easing phase(IOP-4),with ΔCO_(2)/ΔCO constantly increasing from IOP-2 to IOP-3 and finally IOP-4,consistent with recovery in industrial emissions associated with the staged resumption of economic activity.On average,ΔCO_(2) declined sharply throughout the days during IOP-2 but increased gradually throughout the days during IOP-4.The findings showcase the significant role of emission reduction in accounting for the dramatic changes in measured atmosphericΔCO_(2) and ΔCH_(4) associated with the COVID-19 lockdown and recovery.
基金supported by the National Natural Science Foundation of China (Nos.22106129,22076174 and 91843301)。
文摘The outbreak of COVID-19 has caused concerns globally.To reduce the rapid transmission of the virus,strict city lockdown measures were conducted in different regions.China is the country that takes the earliest home-based quarantine for people.Although normal industrial and social activities were suspended,the spread of virus was efficiently controlled.Simultaneously,another merit of the city lockdown measure was noticed,which is the improvement of the air quality.Contamination levels of multiple atmospheric pollutants were decreased.However,in this work,24 and 14 air fine particulate matter(PM_(2.5))samples were continuously collected before and during COVID-19 city lockdown in Linfen(a typical heavy industrial city in China),and intriguingly,the unreduced concentration was found for environmentally persistent free radicals(EPFRs)in PM_(2.5)after normal life suspension.The primary non-stopped coal combustion source and secondary Cu-related atmospheric reaction may have impacts on this phenomenon.The cigarette-based assessment model also indicated possible exposure risks of PM_(2.5)-bound EPFRs during lockdown of Linfen.This study revealed not all the contaminants in the atmosphere had an apparent concentration decrease during city lockdown,suggesting the pollutants with complicated sources and formation mechanisms,like EPFRs in PM_(2.5),still should not be ignored.
基金financially supported by the National Key R&D Program of China(No.2018YFC0213105)the National Science Foundation of China(No.91644105)the Natural Science Foundation of Shanghai(18230722600,19ZR1421100,20ZR1422000)。
文摘The coronavirus(COVID-19)pandemic is disrupting the world from many aspects.In this study,the impact of emission variations on PM_(2.5)-bound elemental species and health risks associated to inhalation exposure has been analyzed based on real-time measurements at a remote coastal site in Shanghai during the pandemic.Most trace elemental species decreased significantly and displayed almost no diel peaks during the lockdown.After the lockdown,they rebounded rapidly,of which V and Ni even exceeded the levels before the lockdown,suggesting the recovery of both inland and shipping activities.Five sources were identified based on receptor modeling.Coal combustion accounted for more than 70%of the measured elemental concentrations before and during the lockdown.Shipping emissions,fugitive/mineral dust,and waste incineration all showed elevated contributions after the lockdown.The total non-carcinogenic risk(HQ)for the target elements exceeded the risk threshold for both children and adults with chloride as the predominant species contributing to HQ.Whereas,the total carcinogenic risk(TR)for adults was above the acceptable level and much higher than that for children.Waste incineration was the largest contributor to HQ,while manufacture processing and coal combustion were the main sources of TR.Lockdown control measures were beneficial for lowering the carcinogenic risk while unexpectedly increased the non-carcinogenic risk.From the perspective of health effects,priorities of control measures should be given to waste incineration,manufacture processing,and coal combustion.A balanced way should be reached between both lowering the levels of air pollutants and their health risks.
文摘The higher concentration of PM_(10) and PM_(2.5) in the lower atmosphere is severely harmful for human health and it also makes visibility diminution along with weather and climate modifications.The main objective is to find out the spatiotemporal variation and dispersal of PM_(10) and PM_(2.5) along with COVID-19 infection in the dusty city Kolkata.The consecutive two years PM_(10) and PM_(2.5) data of different stations have been obtained from State Pollution Control Board,Govt.of West Bengal.Forward trajectory analysis has been done through HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory)model to find the path and direction of air particles.The result showed that the various meteorological or environmental factors(such as temperature,relative humidity,wind,wind speed,pressure and gusty wind)and geographical location regulate the spatiotemporal variation of PM_(10) and PM_(2.5).These factors like high temperature with relative humidity and strong wind influence to disperse the particulate matters from north to south direction from city to outside during summer in Kolkata metropolitan city.During summer(both pre and lockdown years),the height of particles is extended up to 1000 m owing to active atmospheric ventilation whereas in winter it is confined within 100 m.The HYSPLIT model clearly specified that the particles dispersed from south,south-west to north and north east direction due to strong wind.The constant magnification of PM_(10) and PM_(2.5) in the lower atmosphere leads to greater frequency of COVID-19 infections and deaths.In Kolkata,the one of the crucial reasons of high infection and deaths(COVID-19)is co-morbidity of people.
基金the Tianjin Philosophy and Social Science Planning Project“Research on Value-Added Evaluation of Career Adaptability for Engineering Students Oriented towards Outstanding Engineers”,Grant Number TJJXQN22-001.
文摘Under the effects of COVID-19 and a number of ongoing lockdown tactics,anxiety symptoms and poor sleep quality have become common mental health issues among college freshmen and are intimately related to their emotional adaptation.To explore this connection,this study gathered data from a sample of 256 freshmen enrolled in an elite university in China in September 2022.The association between sleep quality,anxiety symptoms,and emotional adaptation was clarified using correlation analysis.Additionally,the mediating function of anxiety symptoms between sleep quality and emotional adaptation was investigated using a structural equation model.The results reveal that:(1)Chinese elite university freshmen who were subjected to prolonged lockdown had poor sleep quality and mild anxiety symptoms;(2)a significant positive correlation between poor sleep quality and anxiety symptoms was identified;(3)anxiety symptoms were found to have a significant negative impact on emotional adaptation;(4)poor sleep quality had a negative impact on emotional adaptation through anxiety symptoms.This research makes a valuable contribution by offering insights into the intricate relationship between sleep quality and emotional adaptation among freshmen in elite Chinese universities during prolonged lockdown conditions,and it is beneficial for schools and educators to further improve school schedules and psychological health initiatives.
基金supported by the National Key Research and Development Program of China(Nos.2018YFC0213104 and 2017YFC0210002)the National Natural Science Foundation of China(Nos.41977184,41941011,and 51778596)+5 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23020301)the Major Projects of High Resolution Earth Observation Systems of National Science and Technology(No.05-Y30B01-9001-19/20-3)the Youth Innovation Promotion Association of CAS(No.2021443),the Young Talent Project of the Center for Excellence in Regional Atmospheric Environment,CAS(CERAE202004)the China Postdoctoral Science Foundation(Nos.2020TQ0320 and 2021M693068)Anhui Provincial Natural Science Foundation(No.2108085QD178)the Fundamental Research Funds for the Central Universities.
文摘Recently,air pollution especially fine particulate matters(PM_(2.5))and ozone(O_(3))has become a severe issue in China.In this study,we first characterized the temporal trends of PM_(2.5) and O_(3) for Beijing,Guangzhou,Shanghai,andWuhan respectively during 2018-2020.The annual mean PM2.5 has decreased by 7.82%-33.92%,while O_(3) concentration showed insignificant variations by-6.77%-4.65%during 2018-2020.The generalized additive models(GAMs)were implemented to quantify the contribution of individual meteorological factors and their gas precursors on PM_(2.5) and O_(3).On a short-term perspective,GAMs modeling shows that the daily variability of PM_(2.5) concentration is largely related to the variation of precursor gases(R=0.67-0.90),while meteorological conditions mainly affect the daily variability of O_(3) concentration(R=0.65-0.80)during 2018-2020.The impact of COVID-19 lockdown on PM_(2.5) and O_(3) concentrations were also quantified by using GAMs.During the 2020 lockdown,PM_(2.5) decreased significantly for these megacities,yet the ozone concentration showed an increasing trend compared to 2019.The GAMs analysis indicated that the contribution of precursor gases to PM_(2.5) and O_(3) changes is 3-8 times higher than that of meteorological factors.In general,GAMsmodeling on air quality is helpful to the understanding and control of PM2.5 and O3 pollution in China.
基金supported by National Natural Science Foundation of China(No.42005082).
文摘Organic aerosol(OA)is a major component of atmospheric particulate matter(PM)with complex composition and formation processes influenced by various factors.Emission reduction can alter both precursors and oxidants which further affects secondary OA formation.Here we provide an observational analysis of secondary OA(SOA)variation properties in Yangtze River Delta(YRD)of eastern China in response to large scale of emission reduction during Chinese New Year(CNY)holidays from 2015 to 2020,and the COVID-19 pandemic period from January to March,2020.We found a 17%increase of SOA proportion during the COVID lockdown.The relative enrichment of SOA is also found during multi-year CNY holidays with dramatic reduction of anthropogenic emissions.Two types of oxygenated OA(OOA)influenced by mixed emissions and SOA formation were found to be the dominant components during the lockdown in YRD region.Our results highlight that these emission-reduction-induced changes in organic aerosol need to be considered in the future to optimize air pollution control measures.
基金This research was supported by the National Natural Science Foundation of China[grant numbers 91744311 and 41922038]the International Cooperation project of Jiangsu Provincial Science and Technology Agency[grant number BZ2017066].
文摘The explosive spread of the 2019 novel coronavirus(COVID-19)provides a unique chance to rethink the relationship between human activity and air pollution.Though related studies have revealed substantial reductions in primary emissions,obvious differences do exist in the responses of secondary pollutants,like ozone(0_(3))pollution.However,the regional disparities of O_(3)responses and their causes have still not been fully investigated.To better elucidate the interrelationship between anthropogenic emissions,chemical production,and meteorological conditions,O_(3)responses caused by lockdowns over different regions were comprehensively explored at a global scale.Observational signals of air-quality change were derived from multi-year surface measurements and satellite retrievals.With similar substantial drops in nitrogen dioxide(NO_(2)),ozone shows rising signals in most areas of both East Asia and Europe,even up to~14 ppb,while a non-negligible declining signal exists in North America,by about 2-4 ppb.Furthermore,the drivers behind the different O_(3)responses are discussed based on meteorological analysis and O_(3)sensitivity diagnosis.On the one hand,O_(3)responses to NO_(2)declines can be affected by the primary dependence on its precursors.On the other hand,it is also highly dependent on meteorological factors,especially temperature.Our study further highlights the great importance of taking into consideration both the regional disparities and synergistic effects of precursor reductions and meteorological influence for scientific mitigation of O_(3)pollution.
基金supported by the National Science Foundation of China(Grant.No.41521004)the Gansu Provincial Special Fund Project for Guiding Scientific and Technological Innovation and Development(Grant No.2019ZX-06)the Fundamental Research Funds for the Central Universit-ies(lzujbky-2021-kb12)。
文摘Estimating the impacts on PM_(2.5)pollution and CO_(2)emissions by human activities in different urban regions is important for developing efficient policies.In early 2020,China implemented a lockdown policy to contain the spread of COVID-19,resulting in a significant reduction of human activities.This event presents a convenient opportunity to study the impact of human activities in the transportation and industrial sectors on air pollution.Here,we investigate the variations in air quality attributed to the COVID-19 lockdown policy in the megacities of China by combining in-situ environmental and meteorological datasets,the Suomi-NPP/VIIRS and the CO_(2)emissions from the Carbon Monitor project.Our study shows that PM_(2.5)concentrations in the spring of 2020 decreased by 41.87%in the Yangtze River Delta(YRD)and 43.30%in the Pearl River Delta(PRD),respectively,owing to the significant shutdown of traffic and manufacturing industries.However,PM_(2.5)concentrations in the Beijing-Tianjin-Hebei(BTH)region only decreased by 2.01%because the energy and steel industries were not fully paused.In addition,unfavorable weather conditions contributed to further increases in the PM_(2.5)concentration.Furthermore,CO_(2)concentrations were not significantly affected in China during the short-term emission reduction,despite a 19.52%reduction in CO_(2)emissions compared to the same period in 2019.Our results suggest that concerted efforts from different emission sectors and effective long-term emission reduction strategies are necessary to control air pollution and CO_(2)emissions.
基金This research is supported by the National Natural Science Foundation of China[Grant No.71773127].
文摘In this paper,we study how China’s stock market reacts to the sudden outbreak of COVID-19 in 2020,particularly to the announcement of the pandemic lockdown.In general,we observe reversals both at the industry level and at the firm level due to investors’overreactions to the pandemic lockdown.For industryand firm-level stocks with positive cumulative abnormal returns(CARs)in the event window when Wuhan was locked down,the reversals are stronger.Thus,the reversal effects are mostly driven by industries and stocks that positively overreact to COVID-19 than do others.Further investigation shows that overreactions are stronger for stocks with lower institutional ownership,which means that retail investors react more strongly to COVID-19.Among stocks with positive CARs in the event window,those with higher idiosyncratic volatilities and lower book-to-market ratios tend to have worse performance after one month.
基金Thailand Science Research and Innovation(TSRI)National Science,Research and Innovation Fund(NSRF).Funding number 2492895This research is financially supported by Thailand Science Research and Innovation(TSRI),National Science,Research and Innovation Fund(NSRF)(Fiscal Year 2022).
文摘Background:Several countries used varied degrees of social isolation measures in response to the COVID-19 outbreak.In 2021,the lockdown in Thailand began on July 20 and lasted for the following six weeks.The lockdown has extremely detrimental effects on the economy and society,even though it may reduce the number of COVID-19 instances.Our goals are to assess the impact of the lockdown policy,the commencement time of lockdown,and the vaccination rate on the number of COVID-19 cases in Thailand in 2021.Methods:We modeled the dynamics of COVID-19 in Thailand throughout 2021 using the SEIR model.The Google Mobility Index,vaccine distribution rate,and lockdown were added to the model.The Google Mobility Index represents the movement of individuals during a pandemic and shows how people react to lockdown.The model also examines the effect of vaccination rate on the incidence of COVID-19.Results:The modeling approach demonstrates that a 6-week lockdown decreases the incidence number of COVID-19 by approximately 15.49e18.17%,depending on the timing of the lockdown compared to a non-lockdown scenario.An increasing vaccination rate potentially reduce the incidence number of COVID-19 by 5.12e18.35%without launching a lockdown.Conclusion:Lockdowns can be an effective method to slow down the spread of COVID-19 when the vaccination program is not fully functional.When the vaccines are easily accessible on a large scale,the lockdown may terminated.
