Evaluating traditional Chinese medicine (TCM) Jie Geng and Huang Qi combination on reducing surgical site infections in colorectal cancer surgeries: A systematic review and meta-analysis.

Postoperative wound infections (PWIs) pose a significant challenge in colorectal cancer surgeries, leading to prolonged hospital stays and increased morbidity. This systematic review and meta-analysis evaluated the efficacy of the traditional Chinese medicine (TCM) combination of Jie Geng and Huang Qi in reducing PWIs following colorectal cancer surgeries. Adhering to PRISMA guidelines, we focused on seven randomized controlled trials (RCTs) involving 1256 patients, examining the incidence of PWIs within 30 days post-surgery, alongside secondary outcomes such as length of hospital stay and antibiotic use. The analysis revealed a significant reduction in PWI incidence in the TCM-treated group compared to controls, with a Risk Ratio of 0.21 (95% CI: 0.14 to 0.30, p < 0.01), a notable decrease in hospital stay (Mean Difference: 1.2 days, 95% CI: 0.15 to 1.28 days, p < 0.01) and a significant reduction in antibiotic use (Risk Ratio: 0.24, 95% CI: 0.16 to 0.36, p < 0.01). These findings suggest that Jie Geng and Huang Qi in TCM could be an effective adjunct in postoperative care for colorectal cancer surgeries, underscoring the need for further high-quality RCTs to substantiate these results and explore the underlying mechanisms.

The role of traditional Chinese medicine in postoperative wound complications of gastric cancer.

Due to the high risks of postoperative complications brought on by gastric cancer, traditional Chinese medicine (TCM) as a commonly used therapy, has exerted its vital role in postoperative recovery care. In this sense, this meta-analysis was conducted to explore the related documents about TCM's impact on gastric cancer postoperative recovery. During the research, we explored a total of 1549 results from databases PubMed, China National Knowledge Infrastructure (CNKI), Embase, Cochrane Library and Web of Science (WoS). Thirty-two clinical randomized trials (RCTs) were then selected and analysed for this meta-analysis by using the software RevMan 5.4 (under PRISMA 2020 regulations), with a population of 3178 patients. Data prove that TCM therapy reduced the risks for postoperative complications exposure by an estimated average of 19% (95% CI). Among the complications, TCM therapy suppressed the risks of wound infection and incisional infections by 53% and 48% respectively. Meanwhile, the patient's wound healing duration exhibited a significant reduction compared to those without TCM treatment, with a difference at around 0.74 days (95% CI). TCM also exerted its potential to strengthen the patient's immune and health conditions, leading to a significantly promoted gastrointestinal function in the patients with a shorter duration to release first exhaustion and defecation compared to those with no TCM therapy. In addition, similar promoted phenomena also exist in those patients with TCM therapy in terms of their immunity and nutritional conditions. These facts all indicate a positive impact of TCM therapy in clinical applications.

Aerosol liquid water in PM2.5 and its roles in secondary aerosol formation at a regional site of Yangtze River Delta.

Aerosol liquid water content (ALWC) plays an important role in secondary aerosol formation. In this study, a whole year field campaign was conducted at Shanxi in north Zhejiang Province during 2021. ALWC estimated by ISORROPIA-II was then investigated to explore its characteristics and relationship with secondary aerosols. ALWC exhibited a highest value in spring (66.38 µg/m3), followed by winter (45.08 µg/m3), summer (41.64 µg/m3), and autumn (35.01 µg/m3), respectively. It was supposed that the secondary inorganic aerosols (SIA) were facilitated under higher ALWC conditions (RH > 80%), while the secondary organic species tended to form under lower ALWC levels. Higher RH (> 80%) promoted the NO3- formation via gas-particle partitioning, while SO42- was generated at a relative lower RH (> 50%). The ALWC was more sensitive to NO3- (R = 0.94) than SO42- (R = 0.90). Thus, the self-amplifying processes between the ALWC and SIA enhanced the particle mass growth. The sensitivity of ALWC and OX (NO2 + O3) to secondary organic carbon (SOC) varied in different seasons at Shanxi, more sensitive to aqueous-phase reactions (daytime R = 0.84; nighttime R = 0.54) than photochemical oxidation (daytime R = 0.23; nighttime R = 0.41) in wintertime with a high level of OX (daytime: 130-140 µg/m3; nighttime: 100-140 µg/m3). The self-amplifying process of ALWC and SIA and the aqueous-phase formation of SOC will enhance aerosol formation, contributing to air pollution and reduction of visibility.

Plastic substrate and residual time of microplastics in the urban river shape the composition and structure of bacterial communities in plastisphere.

The widespread secondary microplastics (MPs) in urban freshwater, originating from plastic wastes, have created a new habitat called plastisphere for microorganisms. The factors influencing the structure and ecological risks of the microbial community within the plastisphere are not yet fully understood. We conducted an in-site incubation experiment in an urban river, using MPs from garbage bags (GB), shopping bags (SB), and plastic bottles (PB). Bacterial communities in water and plastisphere incubated for 2 and 4 weeks were analyzed by 16S high-throughput sequencing. The results showed the bacterial composition of the plastisphere, especially the PB, exhibited enrichment of plastic-degrading and photoautotrophic taxa. Diversity declined in GB and PB but increased in SB plastisphere. Abundance analysis revealed distinct bacterial species that were enriched or depleted in each type of plastisphere. As the succession progressed, the differences in community structure was more pronounced, and the decline in the complexity of bacterial community within each plastisphere suggested increasing specialization. All the plastisphere exhibited elevated pathogenicity at the second or forth week, compared to bacterial communities related to natural particles. These findings highlighted the continually evolving plastisphere in urban rivers was influenced by the plastic substrates, and attention should be paid to fragile plastic wastes due to the rapidly increasing pathogenicity of the bacterial community attached to them.

Evidence for Reducing Volatile Organic Compounds to Improve Air Quality from Concurrent Observations and In Situ Simulations at 10 Stations in Eastern China.

Ground-level ozone (O3) has been an emerging air pollution in China and interacts with fine particulate matters (PM2.5). We synthesized observations of O3 and its precursors in two summer months of 2020 at 10 sites in the Zhejiang province, East China and simulated the in situ photochemistry. O3 pollution in the northeastern Zhejiang province was more serious than that in the southwest. The site-average daytime O3 increment correlated well (R2 = 0.73) with the total reactivity of volatile organic compounds (VOCs) and carbon monoxide toward the hydroxyl radical (OH) in urban areas. Model simulation revealed that the main function of nitrogen oxides (NOx) at the rural sites where isoprene accounted for >85% of OH reactivity of VOCs was to facilitate the radical cycling. With NOx reduction from 0 to 90%, the self-reactions between peroxy radicals (Self-Rxns), a proven pathway for secondary organic aerosol formation, were intensified by up to 23-fold in a NOx-rich environment. In contrast, reducing VOCs could weaken the Self-Rxns while reducing O3 production rate and atmospheric oxidation capacity. This study observes and simulates O3 chemistry based on extensive measurements in typical Chinese cities, highlighting the necessity of reducing VOCs for co-benefit of O3 and PM2.5.

Airborne black carbon variations during the COVID-19 lockdown in the Yangtze River Delta megacities suggest actions to curb global warming.

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.

HupA, the main undecaprenyl pyrophosphate and phosphatidylglycerol phosphate phosphatase in Helicobacter pylori is essential for colonization of the stomach.

The biogenesis of bacterial cell-envelope polysaccharides requires the translocation, across the plasma membrane, of sugar sub-units that are produced inside the cytoplasm. To this end, the hydrophilic sugars are anchored to a lipid phosphate carrier (undecaprenyl phosphate (C55-P)), yielding membrane intermediates which are translocated to the outer face of the membrane. Finally, the glycan moiety is transferred to a nascent acceptor polymer, releasing the carrier in the "inactive" undecaprenyl pyrophosphate (C55-PP) form. Thus, C55-P is generated through the dephosphorylation of C55-PP, itself arising from either de novo synthesis or recycling. Two types of integral membrane C55-PP phosphatases were described: BacA enzymes and a sub-group of PAP2 enzymes (type 2 phosphatidic acid phosphatases). The human pathogen Helicobacter pylori does not contain BacA homologue but has four membrane PAP2 proteins: LpxE, LpxF, HP0350 and HP0851. Here, we report the physiological role of HP0851, renamed HupA, via multiple and complementary approaches ranging from a detailed biochemical characterization to the assessment of its effect on cell envelope metabolism and microbe-host interactions. HupA displays a dual function as being the main C55-PP pyrophosphatase (UppP) and phosphatidylglycerol phosphate phosphatase (PGPase). Although not essential in vitro, HupA was essential in vivo for stomach colonization. In vitro, the remaining UppP activity was carried out by LpxE in addition to its lipid A 1-phosphate phosphatase activity. Both HupA and LpxE have crucial roles in the biosynthesis of several cell wall polysaccharides and thus constitute potential targets for new therapeutic strategies.

A TP53 mutation model for the prediction of prognosis and therapeutic responses in head and neck squamous cell carcinoma.

BACKGROUND: Tumor protein p53 (TP53) is the most frequently mutated gene in head and neck squamous cell carcinoma (HNSC), and TP53 mutations are associated with inhibited immune signatures and poor prognosis. We established a TP53 mutation associated risk score model to evaluate the prognosis and therapeutic responses of patients with HNSC. METHODS: Differentially expressed genes between patients with and without TP53 mutations were determined by using data from the HNSC cohort in The Cancer Genome Atlas database. Patients with HNSC were divided into high- and low-risk groups based on a prognostic risk score that was generated from ten TP53 mutation associated genes via the multivariate Cox regression model. RESULTS: TP53 was the most common mutant gene in HNSC, and TP53 mutations were associated with immunogenic signatures, including the infiltration of immune cells and expression of immune-associated genes. Patients in the high-risk group had significantly poorer overall survival than those in the low-risk group. The high-risk group showed less response to anti-programmed cell death protein 1 (PD-1) therapy but high sensitivity to some chemotherapies. CONCLUSION: The risk score based on our TP53 mutation model was associated with poorer survival and could act as a specific predictor for assessing prognosis and therapeutic response in patients with HNSC.

Critical Role of Simultaneous Reduction of Atmospheric Odd Oxygen for Winter Haze Mitigation.

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.

MiR-543 promotes tumorigenesis and angiogenesis in non-small cell lung cancer via modulating metastasis associated protein 1.

OBJECTIVE: This study is aimed to explore the role of miR-543 in non-small cell lung cancer (NSCLC), and verify whether miR-543 targets metastasis associated protein 1 (MTA1) to affect tumorigenesis and angiogenesis in NSCLC. METHODS: Firstly, miR-543 mimic and inhibitor were transfected into A549 cells and H1299 cells. The cells proliferation was tested by MTT and clone formation. The cells apoptosis was analyzed by cytometry. Tube formation assay was used to measure the vascularization of cells. qRT-PCR and Western Blot were used to measure the MTA1 expression. Dual-luciferase assay was used to analyze whether miR-543 targets MTA1. Secondly, MTA1 mimic and inhibitor were transfected into cells to analyze the effect of MTA1 on proliferation and angiogenesis in NSCLC cells. Lastly, the nude mice were used to verify the effect of miR-543 on tumorigenesis and angiogeneisis in NSCLC via modulating MATA1. RESULTS: miR-543 overexpression could apparently promote cells proliferation and angiogeneisis in NSCLC cells. Meanwhile, the MTA1 expression was increased after transfecting miR-543 mimic. Dual luciferase reporter assay revealed MTA1 was a downstream target of miR-543. Further studies showed that inhibition of MTA1 weakened the role of miR-543 overexpression in NSCLC cells. Vivo experiments revealed that miR-543 promoted cells proliferation and angiogenesis in tumor tissues via modulating MTA1. CONCLUSION: miR-543 could target MTA1 to promote tumorigenesis and angiogenesis in NSCLC via targeting MTA1.

Sample-to-cutoff ratios using Architect HIV Ag/Ab Combo: The influence with the results of supplemental tests and optimal cutoff value to predict HIV infection.

BACKGROUND: The Architect HIV Ag/Ab Combo has excellent performance for HIV screening; however, the false-positive rate (FPR) was high in low HIV prevalence setting. OBJECTIVES: The purpose of this study was to analyze the influence of sample-to-cutoff (s/co) ratios by Architect HIV Ag/Ab Combo with the results of confirmatory test and explore the potential utility of s/co to predict HIV infection. METHODS: A retrospective review on Architect HIV Ag/Ab Combo reactive results was performed at a teaching hospital in Xi'an. The s/co values in different groups, that is, true positives (TP) and false positives (FP), different Western blotting (WB) bands among WB-positive cases, were compared. The receiver operating characteristic curve (ROC) analysis was used to determine the optimal cutoff value for predicting HIV infection. RESULTS: During the study period, 219 out of 84 702 patients were reactive by ARCHITECT with a 0.0992% of HIV prevalence and a 56.25% of FPR. The mean s/co ratios in TP were significantly higher than that in FP (458.15 vs 3.11, P < 0.0001). Among the WB-positive cases, the s/co ratios increased significantly with the increase in the number of bands, P = 0.0065. The optimal cutoff (24.44) by ROC analysis can provide the highest sum of sensitivity (100%) and specificity (100%) with no FP results. CONCLUSIONS: For Architect HIV Ag/Ab Combo, the FPR is reduced when s/co ratios increase, and the s/co ≥24.44 may be reliable to predict HIV infection.

Degradable Chitosan-Collagen Composites Seeded with Cells as Tissue Engineered Heart Valves.

BACKGROUND: Degradable collagen-chitosan composite materials have been used to fabricate tissue engineered heart valves. The aims of this study were to demonstrate that the collagen-chitosan composite scaffolds are cytocompatible, and endothelial cells can be differentiated from bone marrow mesenchymal stem cells (BMSCs) when seeded onto the scaffolds. The adhesion and biological activities of the seeded cells were also investigated. METHODS: Collagen-chitosan composite material was used as the cell matrix, and smooth muscle cells, fibroblasts and BMSCs were used as seed cells. After four weeks of in vitro culture, the smooth muscle cells, fibroblasts, and BMSCs were sequentially seeded into the collagen-chitosan composite material. After four weeks in culture, the cellular density and activity were assessed on segments of the tissue engineered heart valve scaffolds to determine the cell viability and proliferation in the collagen-chitosan composite material. RESULTS: The tissue engineered heart valves stained positively for both smooth muscle actin and endothelial cell factor VIII, suggesting that the seeded cells were in fact smooth muscle cells, fibroblasts, and endothelial cells. The 6-ketone prostaglandin content, as measured by radioimmunoassay, of the collagen-chitosan cell culture fluid was higher than that of the serum-free medium (P <0.01). Light and electron microscopy showed that the seeded cells had shapes similar to the morphology of smooth muscle cells, fibroblasts, and endothelial cells. CONCLUSIONS: Endothelial cells can be differentiated from BMSCs when seeded onto the collagen-chitosan composite scaffolds. The seeded cells retained their biological activity after being cultured in vitro and seeded into the collagen-chitosan composite material.

Effect of Si and Holding Time on Ti2Al20La Phase in Al-Ti-La Intermediate Alloy.

The effects of holding time and Si on the content, shape size and structure of Ti2Al20La phase in Al-Ti-La intermediate alloy were investigated by an X-ray diffractometer, scanning electron microscope and transmission electron microscope. The results show that the volume fraction and aspect ratio of Ti2Al20La phase in Al-Ti-La intermediate alloy decrease significantly, from 21% and 2.3 without Si addition to 4% and 2.0 with the addition of 2.3 wt.% Si at a holding time of 15 min at 750 °C, respectively. The Si element will attach to the Ti2Al20La phase and form La-Si binary phase at the grain boundary of α-Al. With the increase of holding time from 15 min to 60 min, the content of Ti2Al20La phase in the alloy gradually decreases and the size decreases significantly. Meanwhile, Al11La3 will dissolve and disappear, while the content of La-Si binary phase increases, and part of Ti2Al20La phase transforms into Ti2(Al20-x,Six)La phase.

Variational Distillation for Multi-View Learning.

Information Bottleneck (IB) provides an information-theoretic principle for multi-view learning by revealing the various components contained in each viewpoint. This highlights the necessity to capture their distinct roles to achieve view-invariance and predictive representations but remains under-explored due to the technical intractability of modeling and organizing innumerable mutual information (MI) terms. Recent studies show that sufficiency and consistency play such key roles in multi-view representation learning, and could be preserved via a variational distillation framework. But when it generalizes to arbitrary viewpoints, such strategy fails as the mutual information terms of consistency become complicated. This paper presents Multi-View Variational Distillation (MV 2D), tackling the above limitations for generalized multi-view learning. Uniquely, MV 2D can recognize useful consistent information and prioritize diverse components by their generalization ability. This guides an analytical and scalable solution to achieving both sufficiency and consistency. Additionally, by rigorously reformulating the IB objective, MV 2D tackles the difficulties in MI optimization and fully realizes the theoretical advantages of the information bottleneck principle. We extensively evaluate our model on diverse tasks to verify its effectiveness, where the considerable gains provide key insights into achieving generalized multi-view representations under a rigorous information-theoretic principle.

Methylation related genes are associated with prognosis of patients with head and neck squamous cell carcinoma via altering tumor immune microenvironment.

Background/purpose: Analysis of methylomes may enable prognostic stratification in patients with head and neck squamous cell carcinoma (HNSCC). This study aimed to identify methylation-related differentially expressed genes (mrDEGs), and to assess their efficacy in predicting patients' survival, tumor immune microenvironment alterations and immune checkpoints in patients with HNSCC. Materials and methods: The methylome and transcriptome data of 528 HNSCC and 50 normal samples from TCGA database were used as training cohort. We identified mrDEGs and constituted a risk score model using Kaplan-Meier analysis and multivariate Cox regression. The prognostic efficacy of the risk score was validated in GSE65858 and GSE41613. We determined the enrichment of previously defined biological processes of mrDEGs. We separated the HNSCC patients into low-risk and high-risk groups and compared their immune cell infiltration and immune checkpoints' expressions. Results: The risk score model was constituted by nine prognostic mrDEGs, including LIMD2, SYCP2, EPHX3, UCLH1, STC2, PRAME, SLC7A4, PLOD2, and ACADL. The risk score was a significant prognostic factor both in training (P < 0.001) and validation dataset (GSE65858: P = 0.008; GSE41613 = 0.015). The prognostic mrDEGs were enriched in multiple immune-associated pathways. Effector immune cells were increased in low-risk patients, including CD8+ T cells, activated CD4+ T cells, and plasma cells, whereas tumor associated M2 macrophages were recruited in the high-risk group. Expressions of immune checkpoints were generally higher in low-risk patients, including CTLA-4, PD-1 and LAG3. Conclusion: The mrDEGs can stratify HNSCC patients' prognosis, which correlates with alterations in tumor immune infiltrations and immune checkpoints.

Identification of prognostic and driver gene mutations in acute myeloid leukemia by a bioinformatics analysis.

Background: The representative gene mutation in the prognostic groups of acute myeloid leukemia (AML) patients is not yet known. The purpose of this study is to identify representative mutations that can help physicians better predict patient prognosis and thus develop better treatment plans. Methods: The Cancer Genome Atlas (TCGA) database was queried for clinical and genetic information, and individuals with AML were classified into 3 groups based on their AML Cancer and Leukemia Group B (CALGB) cytogenetic risk category. Each group's differentially mutated genes (DMGs) were evaluated. Simultaneously, Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to assess the function of DMGs within the 3 distinct groups. We used the driver status and protein impact of DMGs as additional filters to narrow down the list of significant genes. Cox regression analysis was used to examine the survival features of gene mutations in these genes. Results: A cohort of 197 AML patients were divided into 3 groups according to their prognostic subtype: favorable (n=38), intermediate (n=116) and poor (n=43). There were significant differences in age and tumor metastasis rates among the three groups of patients. Patients in the favorable group had the highest rate of tumor metastasis. Different prognosis groups' DMGs were detected. The DMGs were examined for the driver and harmful mutations. We considered the DMGs that had driver and harmful mutations and that affected the survival outcomes in the prognostic groups as the key gene mutations. The group with a favorable prognosis carried specific gene mutations for KIT and WT1. The intermediate prognostic group contained mutations in the genes IDH2, NRAS, NPM1, FLT3, RUNX1, DNMT1A, and MUC16. In the group with a poor prognosis, the representative genes were KRAS, TP53, IDH1, IDH2, and DNMT3A, with TP53 mutations substantially correlated with overall patient survival. Conclusions: We performed the systemic analysis of the gene mutation in patients with AML and identified representative and driver mutations between the prognostic group. identification of representative and driver mutations between the prognostic group can help predict the prognosis of patients with AML and guide treatment decisions.

Identification of key modules and micro RNAs associated with colorectal cancer via a weighted gene co-expression network analysis and competing endogenous RNA network analysis.

Background: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide, and the incidence of CRC has increased rapidly in recent years. Due to the high invasiveness of colonoscopy and the low accuracy of alternative diagnostic methods, the diagnosis of CRC remains a serious problem. Thus, molecular biomarkers for CRC need to be identified. Methods: In this study, RNA-sequencing data from The Cancer Genome Atlas (TCGA) database were used to identify the long non-coding RNAs (lncRNAs), messenger RNAs (mRNAs), and micro RNAs (miRNAs) that were differentially expressed between the CRC and normal tissues. Based on the gene expression and clinical features, the results of the weighted gene co-expression network analysis (WGCNA) and the binding relationships between miRNAs and lncRNAs and mRNAs were used to establish a CRC-related competing endogenous RNA (ceRNA) network. Results: The core miRNAs (i.e., mir-874, mir-92a-1, and mir-940) in the network were identified. Among them, mir-874 was negatively correlated with the overall survival (OS) of patients. The protein-coding genes in the ceRNA network included IZUMO4, WT1, NPEPL1, TEX22, PPFIA4, and SFXN3, and the lncRNAs were LINC00858 and PRR7-AS1. These genes were significantly highly expressed in CRC according to validations in other independent data sets. Conclusions: In conclusion, this study established a network of the co-expressed ceRNAs associated with CRC and identified the genes and miRNAs related to the prognosis of CRC patients.

Modeling the biogenic isoprene emission and its impact on ozone pollution in Zhejiang province, China.

Isoprene is the most abundantly emitted biogenic volatile organic compound (BVOC), which plays an essential role in producing tropospheric ozone (O3). However, the simulations of isoprene emissions have not been sufficiently verified over Yangtze River Delta (YRD), and few studies have specifically addressed its impact on O3 formation. In this study, we simulated the isoprene emissions in Zhejiang Province (ZJ), a region with the largest BVOC emission in YRD, in August 2020 using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) and the latest Moderate Resolution Imaging Spectroradiometer (MODIS) products, and investigated its contributions to O3 using the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) model. The model has a good performance on isoprene simulations over urban and suburban areas, with mean biases of -0.16-0.12 ppb, but underestimated the concentrations at forest sites (mainly due to bamboo). Regionally, the simulated formaldehyde concentrations over forests agree well with the satellite observations. In August 2020, the total isoprene emission in ZJ was 125.1 GgC, with higher emissions in western ZJ and relatively lower emissions in eastern coastal regions. The spatial pattern of isoprene concentrations is similar to its emissions, and the maximum daytime average concentrations are above 3.5 ppb. The spatial pattern of its contribution to daily maximum 8 h average O3 concentrations is significantly different from the emissions and concentrations, which shows a higher impact in northern ZJ (>6 ppb) and relatively lower impact in southern ZJ (1-3 ppb). The mean contribution over ZJ is 8.9 %, with daily variation in the range of 3.1 % to 13.4 %. For different cities, the monthly mean contribution is in the range of 4.6 % to 14.3 %, and the maximum daily contribution reaches about 25 %. These findings help understand the summertime O3 pollution in ZJ and the YRD region of China.

Characteristics and sources of ambient Volatile Organic Compounds (VOCs) at a regional background site, YRD region, China: Significant influence of solvent evaporation during hot months.

Continuous measurement of 98 volatile organic compounds (VOCs) was conducted during 2017-2019 at a regional background site (Shanxi) located at northeast of Zhejiang Province, YRD region, China. The average concentration of total VOCs (TVOCs) was 25.4 ± 18.4 ppbv, and an increasing trend (+12.2 %) was observed. Alkanes were the most abundant VOC group among all seasons, accounting for 43.5 % of TVOCs. Oxygenated VOCs (OVOCs), aromatics, halides and alkenes contributed 15.9 %, 15.7 %, 11.7 % and 10.3 % of TVOCs concentration, respectively. Biogenic VOCs (BVOCs) and OVOCs showed distinguished diurnal cycle from primary anthropogenic VOCs. Photochemical reactivity analysis based on ozone formation potential (OFP) and OH loss rate (LOH) indicated that aromatics and alkenes were the most significant contributor, respectively. Toluene, xylene (m/p- and o-), ethene and propene were the largest contributor of annual OFP, with the mean OFP being 33.8 ± 44.3 µg·m-3, 31.9 ± 32.1 µg·m-3, 9.29 ± 11.4 µg·m-3, 22.1 ± 21.3 µg·m-3 and 12.8 ± 19.5 µg·m-3, respectively. Seven sources were identified with positive matrix factorization (PMF): petrochemical industry (13.8 %), biogenic emission (1.0 %), solvent usage-toluene (16.9 %), vehicular exhaust (43.8 %), Integrated circuits industry (3.8 %), solvent usage-C8 aromatics (10.9 %), and gasoline evaporation (9.8 %). Vehicular exhaust was the most significant source (43.8 %) during the whole measurement period. Solvent usage, petrochemical industry, and gasoline evaporation showed high temperature dependency. The integrated contribution of solvent usage and industrial processes were higher than vehicular exhaust during hot months. These sources also have higher chemical reactivities and can contribute more on O3 formation. Our results are helpful on determining the control strategies aiming at alleviating O3 pollution.