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1.
Environ Sci Pollut Res Int ; 2022 Jun 23.
Article in English | MEDLINE | ID: covidwho-1899267

ABSTRACT

Civil aviation is an important source of air pollutants, but this field has received insufficient attention in China. Based on the standard emissions model of the International Civil Aviation Organization (ICAO) and actual flight information from 241 airports, this study estimated a comprehensive emissions inventory for 2010-2020 by considering the impacts of mixing layer height. The results showed that annual pollutant emissions rapidly trended upward along with population and economic growth; however, the emissions decreased owing to the impacts of the COVID-19 pandemic. In 2020, the emissions of carbon monoxide (CO), nitrogen oxides (NOX), particulate matter (PM), methane (CH4), nitrous oxide (N2O), carbon dioxide (CO2), and water vapor (H2O) were 34.34, 65.73, 0.10, 0.34, 0.40, 14,706.26, and 5733.11 Gg, respectively. The emissions of total volatile organic compounds (VOCs) from China's civil airports in 2020 were estimated at 17.20 Gg; the major components were formic acid (1.70 Gg), acetic acid (1.62 Gg), 1-butylene (1.03 Gg), acetone (0.96 Gg), and acetaldehyde (0.93 Gg). The distribution of pollutant emissions was consistent with the level of economic development, mainly in Beijing, Guangzhou, and Shanghai. In addition, we estimated future pollution trends for the aviation industry under four scenarios. Under the comprehensive scenario, which considered the impacts of economic growth, passenger turnover, cargo turnover, COVID-19, and technological efficiency, the levels of typical pollutants were expected to increase by nearly 1.51-fold from 2010 to 2035.

2.
Travel Behaviour and Society ; 28:75-89, 2022.
Article in English | ScienceDirect | ID: covidwho-1730118

ABSTRACT

Station-based bike sharing (SBBS) not only provides commuters with direct “door-to-door” trips, but also plays a vital role in addressing the “first/last mile” challenges for public transportation system. However, there is a lack of research into portraying year-to-year changes in SBBS commuter behaviors. With five-year (from 2016 to 2020) SBBS smart card data collected in Nanjing, China, a longitudinal analysis is performed in this study to trace yearly dynamics of commuter behaviors at an individual level. We identify two sorts of SBBS commuters (i.e., SBBS-alone and SBBS-metro commuters) based on users’ spatial-temporal travel regularities. The paper finds that (i) the number of SBBS users presented a considerable fluctuation trend over a five-year span, while the proportion of SBBS commuters stabilized at an equilibrium level;(ii) the COVID-19 outbreak accelerated the decline in the proportion of female and young SBBS commuters;(iii) most SBBS commuters were recorded for only one year out of five, while the share of commuters who used SBBS for four years or more is tiny, <5%;(iv) the trip duration of SBBS-alone commuters was significantly longer than that of SBBS-metro commuters, and both showed some increase during the COVID-19 pandemic;(v) the number of non-loop trip chains was dramatically higher than that of loop trip chains, which is more prominent among SBBS-metro commuters. Our findings could provide valuable insights into the behavioral dynamics of SBBS commuters and offer recommendations on how policy makers and transportation planners could respond to these precipitate changes.

3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-323617

ABSTRACT

This paper aims to study the trend of aircraft emission in China. The multiyear emission inventories of HC, CO, NO X , SO 2 and PM 2.5 in the period 2010–2030 were developed. Results show that the total amount of all targeted pollutants from China's civil airports climbed from approximately 82407 tons in 2010 to 164275 tons in 2019. It is expected that the total amount of pollutants will reach 400845 tons by 2030. Pollutant emissions had the lowest growth rate in 2019 and the highest growth rate in 2013 (4.1% and 13.3%, respectively). From 2013 to 2019, the rate of increase in airport pollutant emissions began to decline. In 2019, the emissions of HC, CO, NO X , SO 2 and PM 2.5 are 6251, 53614, 97059, 6248 and 1102 tons, respectively. COVID-19 had a significant impact on airport emissions. By comparing the statistical value and the predicted value of airport emissions in 2020, we found that COVID-19 reduced the emissions of ZHHH and national by 46.33% and 30.45% respectively. In 2019, the East has the highest contribution rate of 27.6%, and Xinjiang has the lowest contribution rate of 3.6%. The emissions of the seven aviation regions were in the order of east > central south > southwest > north > northeast > northwest > Xinjiang.

4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-313443

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by coronavirus SARS-CoV-2, is known to disproportionately affect older individuals1,2. How aging processes affect the disease progression remains largely unknown. Here we found that DNA damage, one of the major causes of aging3, promoted susceptibility to SARS-CoV-2 infection in cells and intestinal organoids. SARS-CoV-2 entry was facilitated by DNA damage caused by telomere attrition or extrinsic genotoxic stress and hampered by inhibition of DNA damage response (DDR). Mechanistic analysis revealed that DDR increased expression of ACE2, the receptor of SARS-CoV-2, by activation of transcription factor c-Jun in vitro and in vivo. Expression of ACE2 was elevated in the older tissues and positively correlated with γH2Ax and phosphorylated c-Jun (p-c-Jun). Finally, targeting DNA damage by increasing the DNA repair capacity, alleviated cell susceptibility to SARS-CoV-2. Our data provide insights into the age-associated differences in SARS-CoV-2 infection and a novel target for anti-viral intervention.

5.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-312680

ABSTRACT

Coronavirus disease 2019 (COVID-19) has triggered a worldwide outbreak of pandemic, and transportation services have played a key role in coronavirus transmission. Although not crowded in a confined space like a bus or a metro car, bike sharing users will be exposed to the bike surface and take the transmission risk. During the COVID-19 pandemic, how to meet user demand and avoid virus spreading has become an important issue for bike sharing. Based on the trip data of bike sharing in Nanjing, China, this study analyzes the travel demand and operation management before and after the pandemic outbreak from the perspective of stations, users, and bikes. Semi-logarithmic difference-in-differences model, visualization methods, and statistic indexes are applied to explore the transportation service and risk prevention of bike sharing during the pandemic. The results show that pandemic control strategies sharply reduced user demand, and commuting trips decreased more significantly. Some stations around health and religious places become more important. Men and older adults are more dependent on bike sharing systems. Besides, the trip decrease reduces user contact and increases idle bikes. And a new concept of user distancing is proposed to avoid transmission risk and activate idle bikes. This study evaluates the role of shared micro-mobility during the COVID-19 pandemic, and also inspires the blocking of viral transmission within the city.

6.
Infect Dis Poverty ; 10(1): 140, 2021 Dec 28.
Article in English | MEDLINE | ID: covidwho-1639437

ABSTRACT

BACKGROUND: Reaching optimal vaccination rates is an essential public health strategy to control the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to simulate the optimal vaccination strategy to control the disease by developing an age-specific model based on the current transmission patterns of COVID-19 in Wuhan City, China. METHODS: We collected two indicators of COVID-19, including illness onset data and age of confirmed case in Wuhan City, from December 2, 2019, to March 16, 2020. The reported cases were divided into four age groups: group 1, ≤ 14 years old; group 2, 15 to 44 years old; group 3, 44 to 64 years old; and group 4, ≥ 65 years old. An age-specific susceptible-exposed-symptomatic-asymptomatic-recovered/removed model was developed to estimate the transmissibility and simulate the optimal vaccination strategy. The effective reproduction number (Reff) was used to estimate the transmission interaction in different age groups. RESULTS: A total of 47 722 new cases were reported in Wuhan City from December 2, 2019, to March 16, 2020. Before the travel ban of Wuhan City, the highest transmissibility was observed among age group 2 (Reff = 4.28), followed by group 2 to 3 (Reff = 2.61), and group 2 to 4 (Reff = 1.69). China should vaccinate at least 85% of the total population to interrupt transmission. The priority for controlling transmission should be to vaccinate 5% to 8% of individuals in age group 2 per day (ultimately vaccinated 90% of age group 2), followed by 10% of age group 3 per day (ultimately vaccinated 90% age group 3). However, the optimal vaccination strategy for reducing the disease severity identified individuals ≥ 65 years old as a priority group, followed by those 45-64 years old. CONCLUSIONS: Approximately 85% of the total population (nearly 1.2 billion people) should be vaccinated to build an immune barrier in China to safely consider removing border restrictions. Based on these results, we concluded that 90% of adults aged 15-64 years should first be vaccinated to prevent transmission in China.


Subject(s)
COVID-19 , Adolescent , Adult , Aged , China , Cities , Humans , Middle Aged , SARS-CoV-2 , Vaccination , Young Adult
7.
Epidemiol Infect ; 149: e219, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1537265

ABSTRACT

As the corona virus disease 2019 (COVID-19) pandemic continues around the world, understanding the transmission characteristics of COVID-19 is vital for prevention and control. We conducted the first study aiming to estimate and compare the relative risk of secondary attack rates (SARs) of COVID-19 in different contact environments. Until 26 July 2021, epidemiological studies and cluster epidemic reports of COVID-19 were retrieved from SCI, Embase, PubMed, CNKI, Wanfang and CBM in English and Chinese, respectively. Relative risks (RRs) were estimated in pairwise comparisons of SARs between different contact environments using the frequentist NMA framework, and the ranking of risks in these environments was calculated using the surface under the cumulative ranking curve (SUCRA). Subgroup analysis was performed by regions. Thirty-two studies with 68 260 participants were identified. Compared with meal or gathering, transportation (RR 10.55, 95% confidence interval (CI) 1.43-77.85), medical care (RR 11.68, 95% CI 1.58-86.61) and work or study places (RR 10.15, 95% CI 1.40-73.38) had lower risk ratios for SARs. Overall, the SUCRA rankings from the highest to the lowest were household (95.3%), meal or gathering (81.4%), public places (58.9%), daily conversation (50.1%), transportation (30.8%), medical care (18.2%) and work or study places (15.3%). Household SARs were significantly higher than other environments in the subgroup of mainland China and sensitive analysis without small sample studies (<100). In light of the risks, stratified personal protection and public health measures need to be in place accordingly, so as close contacts categorising and management.


Subject(s)
COVID-19 , COVID-19/epidemiology , Family Characteristics , Humans , Incidence , Network Meta-Analysis , Pandemics
8.
J Transp Health ; 23: 101264, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1433613

ABSTRACT

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has triggered a worldwide outbreak of pandemic, and transportation services have played a key role in coronavirus transmission. Although not crowded in a confined space like a bus or a metro car, bike-sharing users are exposed to the bike surface and take the transmission risk. During the COVID-19 pandemic, how to meet user demand and avoid virus spreading has become an important issue for bike-sharing. METHODS: Based on the trip data of bike-sharing in Nanjing, China, this study analyzes the travel demand and operation management before and after the pandemic outbreak from the perspectives of stations, users, and bikes. Semi-logarithmic difference-in-differences model, visualization methods, and statistic indexes are applied to explore the transportation service and risk prevention of bike-sharing during the pandemic. RESULTS: Pandemic control strategies sharply reduced user demand, and commuting trips decreased more significantly. Some stations around health and religious places become more important. Men and older adults may be more dependent on bike-sharing systems. The declined trips reduce user contacts and transmission risk. Central urban areas have more user close contacts and higher transmission risk than suburban areas. Besides, a new concept of user distancing is proposed to decrease transmission risk and the number of idle bikes. CONCLUSIONS: This paper is the first research focusing on both user demand and transmission risk of bike-sharing during the COVID-19 pandemic. This study evaluates the mobility role of bike-sharing during the COVID-19 pandemic, and also provides insights into curbing the viral transmission within the city.

9.
Transp Res Interdiscip Perspect ; 11: 100450, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1364500

ABSTRACT

During the COVID-19 crisis, a series of measures were taken to restrict travel and social activities outside the home in order to curb the pandemic and ameliorate its negative effects. These unprecedented measures have had a profound impact on the number and purposes of trips and modes of travel. In China, although the pandemic is now generally under control and transport availability has returned to nearly normal, the extent of the changes in travel behaviour wrought during and after the pandemic still remains unclear. Therefore, the aim of this paper is to investigate the differences in individual travel behaviours during and after the COVID-19 pandemic, using Huzhou as an example. Semi-structured interviews were used to examine the influence of COVID-19 on the travel behaviour and perceptions of different groups. The results indicate that, initially, travel demand was greatly reduced. Second, decreased travel reduced participation in activities, which can have adverse effects on people's health as well as their subjective well-being. Third, the degree and duration of such impacts varied from person to person. Students, lower income cohorts, groups living in small communities with insufficient green spaces, and those working in tourism, catering, informal businesses and transport-related sectors were more vulnerable than others. Policymakers, urban and transport planners should therefore pay attention to the social inequities that arise from unequal access to transport and heterogeneity between individuals. Additionally, public transport systems require further development to promote social cohesion.

10.
Preprint in English | medRxiv | ID: ppmedrxiv-20053645

ABSTRACT

ObjectiveSchool reopening has not yet started in China where the COVID-19 outbreak has reached ending stage, largely due to a great concern about COVID-19 infections on students. We attempted to quantitatively evaluate the risk of COVID-19 infections on students caused by school reopening. Study designWe collected the data of the numbers of teachers, population size and newly confirmed COVID-19 cases in the past 14 days in typical provinces/cities of China, and then analyzed the risk of COVID-19 infections in schools with respect to each province/city. MethodsA step-by-step procedure was explored to calculate the probability of COVID-19 infections on students as transmitted from infected teachers. Two critical assumptions for analysis were proposed: (i) only locally generated cases were counted while imported cases were omitted; (ii) the secondary attack rate of the COVID-19 virus in schools is similar to that in households in China, ranging from 3-10%. ResultsThe probability of COVID-19 resurgence within one week on students of primary, middle and high schools in China (outside Hubei) is extremely low (<0.2%) in each province/city, and such probability can be updated daily and weekly based on the newly confirmed cases in the past 14 days. In some areas without newly confirmed cases in the past 14 days, the risk is zero. ConclusionsOur work provides guidance for local governments to make risk level-based policies for school reopening. Currently, the risk of COVID-19 infections on students is extremely low in China (outside Hubei) and therefore school reopening can be initiated without the endanger of infections on students.

12.
Preprint in English | medRxiv | ID: ppmedrxiv-20035410

ABSTRACT

We report that COVID-19 mortality and recovery rates in Hubei Province, China exponentially decays (R2>0.93) and grows (R2>0.95), respectively. A great number of newly supplied medical resources, including more than 42000 aided health workers, over 26000 makeshift beds and 23000 acute care beds, enabled overwhelming patients to be treated effectively in hospitals. This may inform other countries to deal with the coming COVID-19 pandemic when patients are overwhelming the local health care system.

13.
Preprint in English | medRxiv | ID: ppmedrxiv-20030064

ABSTRACT

The COVID-19 outbreak is on-going in China. Here we estimated the potential total numbers of COVID-19 deaths in China, outside Hubei (in China), Hubei Province, Wuhan City and outside Wuhan (in Hubei) by Boltzmann function-based analyses, which are 3342 (95% CI, 3214, 3527), 111 (109, 114), 3245 (3100, 3423), 2613 (2498, 2767) and 627 (603, 654), respectively. The results may help to evaluate the severity of COVID-19 outbreaks and facilitate timely mental service for the families of passed patients.

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