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1.
Environ Chem Lett ; : 1-10, 2021 Sep 21.
Article in English | MEDLINE | ID: covidwho-1432563

ABSTRACT

Airborne black carbon is a strong warming component of the atmosphere. Therefore, curbing black carbon emissions should slow down global warming. The 2019 coronavirus pandemic (COVID-19) is a unique opportunity for studying the response of black carbon to the varied human activities, in particular due to lockdown policies. Actually, there is few knowledge on the variations of black carbon in China during lockdowns. Here, we studied the concentrations of particulate matter (PM2.5) and black carbon before, during, and after the lockdown in nine sites of the Yangtze River Delta in Eastern China. Results show 40-60% reduction of PM2.5 and 40-50% reduction of black carbon during the lockdown. The classical bimodal peaks of black carbon in the morning and evening rush hours were highly weakened, indicating the substantial decrease of traffic activities. Contributions from fossil fuels combustion to black carbon decreased about 5-10% during the lockdown. Spatial correlation analysis indicated the clustering of the multi-site black carbon concentrations in the Yangtze River Delta during the lockdown. Overall, control of emissions from traffic and industrial activities should be efficient to curb black carbon levels in the frame of a 'green public transit system' for mega-city clusters such as the Yangtze River Delta. Supplementary Information: The online version contains supplementary material available at 10.1007/s10311-021-01327-3.

2.
Environ Sci Technol ; 55(17): 11557-11567, 2021 Sep 07.
Article in English | MEDLINE | ID: covidwho-1371582

ABSTRACT

The lockdown due to COVID-19 created a rare opportunity to examine the nonlinear responses of secondary aerosols, which are formed through atmospheric oxidation of gaseous precursors, to intensive precursor emission reductions. Based on unique observational data sets from six supersites in eastern China during 2019-2021, we found that the lockdown caused considerable decreases (32-61%) in different secondary aerosol components in the study region because of similar-degree precursor reductions. However, due to insufficient combustion-related volatile organic compound (VOC) reduction, odd oxygen (Ox = O3 + NO2) concentration, an indicator of the extent of photochemical processing, showed little change and did not promote more decreases in secondary aerosols. We also found that the Chinese provinces and international cities that experienced reduced Ox during the lockdown usually gained a greater simultaneous PM2.5 decrease than other provinces and cities with an increased Ox. Therefore, we argue that strict VOC control in winter, which has been largely ignored so far, is critical in future policies to mitigate winter haze more efficiently by reducing Ox simultaneously.


Subject(s)
Air Pollutants , Air Pollution , COVID-19 , Aerosols/analysis , Air Pollutants/analysis , Air Pollution/analysis , Air Pollution/prevention & control , China , Communicable Disease Control , Environmental Monitoring , Humans , Oxygen , Particulate Matter/analysis , SARS-CoV-2
3.
Huan Jing Ke Xue ; 42(9): 4116-4125, 2021 Sep 08.
Article in Chinese | MEDLINE | ID: covidwho-1368045

ABSTRACT

Organic carbon (OC), elemental carbon (EC), and PM2.5 concentration data obtained from Shanxi Super Station in Jiashan County of Jiaxing City, in the winter of 2018 and 2019, were analyzed to determine the variation and potential source areas of carbonaceous aerosols. The results show that OC concentrations in the winter of 2018 and 2019 were 6.90 µg·m-3 and 5.63 µg·m-3, respectively, while EC concentrations were 2.47 µg·m-3 and 1.57 µg·m-3, respectively. The concentrations of OC and EC in the winter of 2019 were lower than those in the winter of 2018, by approximately 18.4% and 36.4%, respectively. In 2018 and 2019, the concentrations of secondary organic carbon (SOC), calculated using the minimum R-squared (MRS) method, were 1.49 µg·m-3 and 1.97 µg·m-3, respectively, and the concentrations of primary organic carbon (POC) were 5.41 µg·m-3 and 3.66 µg·m-3, respectively. The proportion of POC in OC showed a downward trend, from 96.0% in December 2018 to 64.9% in February 2020, indicating a decrease of 31.1 percentage points. SOC showed an upward trend, increasing by 31.1 percentage points from 4.0% in December 2018 to 35.1% in February 2020. It is worth noting that with the increase in PM2.5 concentration, the concentration of OC and EC increased by 474.7% and 408.2%, respectively, although the proportion of OC in PM2.5 decreased from 18.8% to 12.3%. and the percentage of OC decreased from 5.8% to 3.3%. The contribution of POC to PM2.5 did not fluctuate, and only decreased significantly above 150 µg·m-3, while the contribution of SOC to PM2.5 first decreased and then increased. In Jiaxing, the potential sources of OC and EC were mainly southern Jiangsu, southeastern Anhui, local Jiaxing, and northern Zhejiang. In the winter of the contribution concentrations of OC and EC in the main potential source regions were approximately 2 µg·m-3 and 6 µg·m-3 lower, respectively, than in winter 2018. The range of high values in the potential source regions also decreased in 2019. Before the COVID-19 epidemic, it was affected by both motor vehicle exhaust emissions and coal burning. During the Spring Festival and home isolation, due to traffic control and other reasons, motor vehicle emissions were reduced, which leaving coal burning as the main contributor.


Subject(s)
Air Pollutants , COVID-19 , Aerosols/analysis , Air Pollutants/analysis , Environmental Monitoring , Humans , Particulate Matter/analysis , SARS-CoV-2
4.
Int J Biol Sci ; 17(8): 1925-1939, 2021.
Article in English | MEDLINE | ID: covidwho-1266906

ABSTRACT

Background: Angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) allow entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into host cells and play essential roles in cancer therapy. However, the functions of ACE2 and TMPRSS2 in kidney cancer remain unclear, especially as kidneys are targets for SARS-CoV-2 infection. Methods: UCSC Xena project, the Cancer Genome Atlas (TCGA), and Gene Expression Omnibus (GEO) databases (GSE30589 and GSE59185) were searched for gene expression in human tissues, gene expression data, and clinical information. Several bioinformatics methods were utilized to analyze the correlation between ACE2 and TMPRSS2 with respect to the prognosis of kidney renal clear cell carcinoma (KIRC) and kidney renal papillary cell carcinoma (KIRP). Results: ACE2 expression was significantly upregulated in tumor tissue, while its downregulation was associated with low survival in KIRC and KIRP patients. TMPRSS2 was downregulated in KIRC and KIRP, and its expression was not correlated with patient survival. According to clinical risk factor-based prediction models, ACE2 exhibits predictive accuracy for kidney cancer prognosis and is correlated with metabolism and immune infiltration. In an animal model, ACE2 expression was remarkably downregulated in SARS-CoV-2-infected cells compared to in the control. Conclusion: ACE2 expression is highly correlated with various metabolic pathways and is involved in immune infiltration.it plays a crucial role than TMPRSS2 in diagnosing and prognosis of kidney cancer patients. The overlap in ACE2 expression between kidney cancer and SARS-CoV-2 infection suggests that patients with KIRC or KIRP are at high risk of developing serious symptoms.


Subject(s)
Angiotensin-Converting Enzyme 2/biosynthesis , COVID-19/complications , Carcinoma, Renal Cell/complications , Kidney Neoplasms/complications , Receptors, Virus/biosynthesis , SARS-CoV-2 , Adult , Aged , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/physiology , Animals , Carcinoma, Renal Cell/immunology , Carcinoma, Renal Cell/metabolism , Carcinoma, Renal Cell/mortality , Chlorocebus aethiops , Down-Regulation , Drug Resistance, Neoplasm , Female , Gene Expression Regulation, Neoplastic , Gene Regulatory Networks , Humans , Kaplan-Meier Estimate , Kidney Neoplasms/immunology , Kidney Neoplasms/metabolism , Kidney Neoplasms/mortality , Lymphocytes, Tumor-Infiltrating/immunology , Male , Middle Aged , Models, Animal , Neoplasm Proteins/biosynthesis , Neoplasm Proteins/genetics , Organ Specificity , Prognosis , Proportional Hazards Models , Receptors, Virus/genetics , Renin-Angiotensin System/physiology , Serine Endopeptidases/biosynthesis , Serine Endopeptidases/genetics , Serine Endopeptidases/physiology , Tissue Array Analysis , Vero Cells
5.
Huan Jing Ke Xue ; 42(4): 1591-1599, 2021 Apr 08.
Article in Chinese | MEDLINE | ID: covidwho-1143847

ABSTRACT

Based on the air pollution emission inventory technical methodology, this study conducted a quantitative analysis on the changes in major air pollutant emissions in Beijing-Tianjin-Hebei and its surrounding areas from the 'New Year Haze' in the autumn and winter of 2016-2017 to the 'Pandemic Haze' in the autumn and winter of 2019-2020. The contributions of the implementation of air pollution prevention and control policies and the COVID-19 pandemic to major air pollutant emission reductions were studied, and their impacts on the regional air quality under adverse meteorological conditions were simulated using an air quality model. The results showed that from the 'New Year Haze' in Dec 2016-Jan 2017 to the 'Pandemic Haze' in Jan-Feb 2020, the major air pollutant emissions in the region had dropped by approximately 50%, and the average concentration of PM2.5 was potentially reduced by more than 40% under adverse meteorological conditions. The most effective emission reduction measures included the clean heating project and raising the standards in key industrial sectors, such as the iron and steel industry, coal-fired boilers, and power plants, which contributed 67.1% and 53.4% of the emission reductions in SO2 and PM2.5, respectively. The COVID-19 pandemic predominantly affected the mobile sources and light industry, which contributed 71.9% and 68.2% of the emission reductions in NOx and VOCs, respectively. The implementation of air pollution prevention and control policies contributed substantially to the improvement of regional air quality, which effectively reduced the intensity and extent of the heavy pollution process under unfavorable meteorological conditions. The regional average PM2.5 concentration was reduced by 26%, and the number of days experiencing heavy pollution decreased by 44%. Due to the impacts of the COVID-19 pandemic, the average PM2.5 concentration in the region was reduced by an additional 24%, and the duration and extent of heavy pollution decreased even further.

6.
Nat Commun ; 12(1): 1147, 2021 02 19.
Article in English | MEDLINE | ID: covidwho-1091490

ABSTRACT

Within a short period of time, COVID-19 grew into a world-wide pandemic. Transmission by pre-symptomatic and asymptomatic viral carriers rendered intervention and containment of the disease extremely challenging. Based on reported infection case studies, we construct an epidemiological model that focuses on transmission around the symptom onset. The model is calibrated against incubation period and pairwise transmission statistics during the initial outbreaks of the pandemic outside Wuhan with minimal non-pharmaceutical interventions. Mathematical treatment of the model yields explicit expressions for the size of latent and pre-symptomatic subpopulations during the exponential growth phase, with the local epidemic growth rate as input. We then explore reduction of the basic reproduction number R0 through specific transmission control measures such as contact tracing, testing, social distancing, wearing masks and sheltering in place. When these measures are implemented in combination, their effects on R0 multiply. We also compare our model behaviour to the first wave of the COVID-19 spreading in various affected regions and highlight generic and less generic features of the pandemic development.


Subject(s)
COVID-19/prevention & control , COVID-19/transmission , Communicable Disease Control/methods , Models, Theoretical , Pandemics/prevention & control , Basic Reproduction Number , Contact Tracing , Humans , Likelihood Functions , Masks , Physical Distancing , Quarantine
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