Based on panel data from 30 provinces in China from 2011 to 2021, this paper uses the coupling coordination degree model, local spatial autocorrelation analysis, and system GMM regression method to systematically examine the spatiotemporal evolution characteristics and influencing factors of the coupling coordination level between China's new quality productivity and carbon emissions. The study found that the annual average of the new quality productivity index increased from 0.1 to 0.23, and the carbon emission intensity decreased from 2.548 to 1.942, indicating a continuous improvement in the synergy level between the two. The coupling coordination degree shows a gradient differentiation of "high in the southeast and low in the northwest". Eastern coastal provinces have risen to high-quality coordination based on digital economy and green technology innovation, while northern energy bases have long been in low value agglomeration due to the "high carbon low efficiency" path dependence. Economic development, opening up to the outside world, and innovation levels significantly promote the improvement of coordination, while environmental regulations have a restraining effect due to the "compliance cost squeeze". Regional heterogeneity analysis shows that the eastern region strengthens technology spillover through global value chain embedding, the northeast is constrained by structural contradictions in heavy industry, and the western region suppresses innovation diffusion due to geographical decline and lagging infrastructure.

Taking the residents in North China as research subjects, the study employed an air quality satisfaction assessment and indicator system to analyse the patterns of air pollution and residents' satisfaction with air quality during both the heating and non-heating seasons. It also examined the factors influencing residents' satisfaction with air quality in North China. The findings revealed that the air quality satisfaction scores for residents were 72.15 during the heating period and 72.62 during the non-heating period, indicating a level of "relatively satisfied". A significant negative correlation was found between the satisfaction index and PM_2.5 levels during the heating period, and a similar negative correlation with PM₁₀ levels during the non-heating season, demonstrating a good model fit. The indicator system showed that public expectations, perceived value and public trust were significantly influenced by heating conditions: public expectations during the heating period were significantly lower than those during the non-heating period; perceived value during the heating period was significantly higher than that during the non-heating period; and public trust during the heating period was significantly lower than that during the non-heating period. Particulate matter pollution remained an important factor affecting residents' satisfaction with air quality in North China. Furthermore, residents' satisfaction with air quality was influenced by multiple factors such as education level, age, and information transparency. Therefore, in future air quality management policies, the government should continue to focus on issues such as PM_2.5 emissions control, air pollution from centralized heating in winter, and the dust management in Inner Mongolia.

Using methods such as composite index evaluation, probabilistic risk characterization, and multi-attribute decision-making, this study investigates the governance challenges posed by multiple risk sources, diverse receptors, and complex exposure pathways in urban ecological environments. It systematically analyzes the transition of risk sources from natural to anthropogenic and from single to multiple origins, as well as the expansion of risk receptors from human health to broader domains such as socio-economic systems, along with the corresponding evaluation indicators. The results show that integrated assessment models can overcome the limitations of single-method approaches by combining information across ecological, socio-economic, and public health dimensions. These models offer a holistic perspective to effectively address complex risk issues and represent a crucial direction for large-scale urban ecological risk assessments, providing scientific support for sustainable urban development and risk management decision-making.

Based on the statistical data of environmental emergencies directly dispatched by the Ministry of Ecology and Environment from 2005 to 2022, this study used the standard deviation ellipse and mean center to explore the spatiotemporal variability of environmental emergencies, the results showed that the total quantity of environmental emergencies in China exhibited a downward tendency. The spatial mean center of environmental emergencies moved to the southwest of China, spanning a total distance of 734 kilometers in the past 17years, Hubei and Shanxi provinces had replaced Zhejiang, Guangdong and Jiangsu provinces as new high-incidence regions. Through the analysis of the characteristics of environmental emergencies, including the causes, pollution media and pollutants, it is found that production safety accidents were the primary cause of environmental emergencies, accounting for 45.12% of the total, followed by traffic accidents, which had surpassed production safety accidents in proportion over the past two years. Water pollution incidents were the most frequent environmental emergencies, and among the particularly major and the major environmental emergencies, water pollution incidents accounted for about 77.55%. Petroleum and heavy metals were two common pollutants in environmental emergencies, accounting for 16.31% and 5.88% of the total incidents, respectively. In the major and above level environmental emergencies, the proportion of heavy metals was higher than that of petroleum.

The molecular compositions of organic components in winter PM_2.5 samples from a typical urban area of Chongqing were analyzed by electrospray ionization coupled with ion mobility spectrometry-time of flight mass spectrometry (ESI-IMS-TOF-MS). Sulfur-containing organics (CHOS+CHNOS) were important components in organic aerosol, and their relative abundance accounted for more than 70% on average. IMS-derived collision cross section, collision-induced dissociation, and Kendrick mass defect analyses verified the presence of organosulfates (OSs). Molecular characterization results indicated that sulfur-containing organics were dominated by carbohydrate and lignin species and had higher oxidation degree in Chongqing urban area compared with other cities. Biogenic and anthropogenic precursors were important sources of sulfur-containing organics. The relationships between aerosol liquid water content, acidity and inorganic sulfate with sulfur-containing organics suggested that aqueous-phase chemistry and acid-catalyzed chemistry play important roles in the formation of sulfur-containing organics.

Oxidative potential (OP) is a crucial indicator for evaluating the capacity of PM_2.5 to trigger oxidative stress. Therefore, this study employed dithiothreitol (DTT) method to measure the OP of PM_2.5. During the observation period, the results indicated that the daily average concentration of atmospheric PM_2.5 in Taiyuan severely exceeded the standard, with a maximum concentration reaching 150.91µg/m³, signifying severe air pollution. The daily average values for volume-normalized (DTT_v) and mass-normalized (DTT_m) DTT activity were (2.90±1.07)nmol/(min·m³) and (38.34±18.91)pmol/(min·µg), respectively. Meanwhile, a significant positive correlation was observed between PM_2.5 mass concentration and DTT_v (r=0.916, P<0.01), while a negative correlation was found with DTT_m. Furthermore, DTT_v exhibited significant correlations (P<0.05) with organic carbon (OC), elemental carbon (EC), metallic elements (Fe, Mn, Zn, Pb), and ionic components (K⁺, Cl^-, etc.) within PM_2.5. These phenomena suggested that DTT activity primarily depends on specific components of PM_2.5. The study further integrated the positive matrix factorization (PMF) model with the multiple linear regression algorithm. Quantitative analysis revealed that solid fuel combustion sources, such as coal combustion, were the most important sources of OP in Taiyuan, contributing 54.7%, followed by motor vehicle sources (23.3%) and dust sources (22.0%).

Per-/polyfluoroalkyl substances (PFASs) and pharmaceuticals and personal care products (PPCPs) were selected as the typical emerging contaminations to investigate the pollution characteristics in the atmospheric particulate matter (APM) of Chengdu. Concentration levels of 25PFASs and 9PPCPs in the APM of Chengdu were analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and source analysis was carried out on the PFASs, and the concentrations of the PFASs were correlated with total suspended particulate matter(TSP). The results showed that 10PFASs and 1PPCPs were detected in the APM. ∑₁₀PFASs concentrations ranged from 4.58 to 647.59pg/m³, with a mean value of 140.81pg/m³, and the highest level was found in PFBA (mean value of 133.18pg/m³). The concentration of ∑PPCPs ranged from 34.98 to 474.00pg/m³, with a mean value of 189.88pg/m³, among which cotinine (CTN) was the only detected PPCP. The principal component analysis indicated that the atmospheric PFASs in the atmosphere of Chengdu were mainly originated from the surfactants, textile and leather industries. Except for 6:2 Fluorotonous Sulfonic Acid (6:2FTSA) and perfluorobutanoic acid (PFBA), all the other PFASs showed a significant positive correlation with TSP(P<0.05), which is related to the presence of Fe₂O₃ oxides and organic matter in atmospheric particulate matter discussed.

This study takes the Wujing Road Tunnel in Tianjin as an example to explore the emission characteristics of benzothiazoles (BTs) in particulate, gaseous pollutants, and road dust. The results show that the concentrations of particulate matter, gaseous pollutants, and BTs in road dust exhibit regular patterns, especially the concentration changes of 2-hydroxybenzothiazole (2-OH-BT) and benzothiazole (BT). Since BTs in the enclosed tunnel environment mainly originate from tire wear particles of motor vehicles, 2-OH-BT and BT can serve as important tracers for identifying non-exhaust emissions from motor vehicles. During the tunnel experiment, the daily traffic volume ranged from 11,972 to 16, 157 vehicles per day, the total carbon (TC) concentration was between 10.85and 15.75μg/m³, and the BTs concentration was between 3.33 and 8.41ng/m³. The gas-particle ratio values of 2-mercaptobenzothiazole (MBT), 2-OH-BT, and BT in the tunnel were generally higher than those in the receptor environment, and 2-OH-BT and BT were the dominant gaseous BTs components. This indicates that most MBT, 2-OH-BT, and BT generated from tire wear sources of motor vehicles are released in the gaseous phase, so the gaseous BTs should not be overlooked. For the calculation of motor vehicle emission factors, the average emission factors of organic carbon (OC), elemental carbon (EC), and PM_2.5 in the Wujing Road Tunnel were 2.80, 1.60, and 13.77mg/(km⋅vehicle), respectively. In the health risk assessment model, the daily exposure to BTs through ingestion was the highest. The daily intake for children and adults was 12.03 and 1.29ng/(kg⋅d), respectively. The total daily exposure for children was more than nine times that of adults, indicating that children may face a greater health threat from traffic pollution than adults.

Cooperative strategies that mitigate competition among dominant functional microorganisms are crucial for efficient nitrogen and phosphorus removal in wastewater treatment. This study investigated a novel single-stage sequencing batch reactor operating under an anaerobic/anaerobic/oxic/anaerobic (A/A₁/O/A₂) mode for 100days to regulate the dynamic balance of phosphorus-accumulating organisms (PAOs), denitrifying PAOs (DPAOs), and denitrifying glycogen-accumulating organisms (DGAOs). The optimized system, featuring a recycle loop and reduced aerobic phase duration, achieved nitrogen and phosphorus removal efficiencies of (95.13%±0.35%) and (94.70%±0.96%), respectively. Mechanistic analysis suggested that the A₁ phase created an anoxic environment conducive to DPAO-mediated denitrifying phosphorus removal, while the A₂ phase supported DGAO-driven denitrifying nitrogen removal using polyhydroxyalkanoates (PHAs) and glycogen (Gly). Extracellular polymeric substance (EPS) analysis revealed increases of 35.38mg/gVSS in protein (PN) and 12.39mg/gVSS in polysaccharide (PS) content, enhancing sludge aggregation. Microbial community analysis demonstrated significant enrichment of Dechloromonas and Ca. Competibacter, with their abundances increasing from 2.24% and 1.53% in R1to 7.61% and 7.94% in R2, respectively. The A/A₁/O/A₂ mode effectively created a synergistic environment for key DPAOs and DGAOs, achieving superior nitrogen and phosphorus removal performance compared to conventional modes.

This study aimed to investigate the influencing mechanism of polystyrene nanoplastics (PS-NPs) in aerobic granular sludge (AGS) systems. The addition of 20mg/L PS-NPs had a negligible impact on the removal of organic matter and phosphorus in the AGS systems. However, it exerted a pronounced inhibitory effect on nitrogen removal, with ammonia nitrogen removal and total nitrogen removal exhibiting a reduction of 21.98% and 41.31% compared to the control group, respectively. Additionally, PS-NPs inhibited the secretion of extracellular polymeric substance (EPS) and altered the EPS structure, making it looser by affecting the secondary structure of proteins. Further studies demonstrated that PS-NPs caused intense oxidative stress within microorganisms by inducing excessive reactive oxygen species (ROS) production, which resulted in lactic dehydrogenase (LDH) levels rising to 151.27% and compromised cell membrane integrity. The long-term presence of PS-NPs led to changes in microbial community structure, inhibiting the growth of denitrifying bacteria, such as the classes Gammaproteobacteria and Alphaproteobacteria. In contrast, the proliferation of the classes Flavobacteria and Chitinophagia was promoted by PS-NPs. Moreover, KEGG database analysis indicated that PS-NPs not only significantly inhibited the pathways related to quorum sensing and metabolic activity, particularly the metabolic pathways of aromatic amino acids, but also reduced the relative abundance of genes encoding denitrifying functional enzymes. This ultimately posed a negative impact on the denitrification performance and the long-term stability of AGS systems.