Pollution Control Research Articles

A Study on Water Quality Characteristics and Classification Scheme for Improving Major Tributaries in Sejong Special Self-Governing City: Development and Application of a Monthly Water Quality Index

This study performed a comprehensive assessment of water quality in four major tributaries - Yeongicheon, Samsungcheon, Bangchukcheon, and Jecheon - in Sejong Special Self-Governing City. The aim was to guide the development of effective river management policies and improve water quality for the first time. Monthly data from the city's water quality monitoring system, from January 2022 to June 2024, were analyzed. The study evaluated 11 water quality parameters. Additionally, we compared BOD and TOC, analyzed correlations between nutrient levels and organic pollutants, performed principal component analysis, and calculated a water quality index, and applied the Monthly Water Quality Index methodology. The results showed that the average water quality index ratings for all four rivers were classified as “Excellent,” aligning with trends observed in living environment standards. However, ratings derived from living environment standards showed greater variability than those from the water quality index, indicating the necessity for a combined water quality index to enhance river management strategies. Seasonal analysis revealed a decline in water quality during the rainy season, emphasizing the need for targeted management during this period. Among the tributaries, Yeongicheon, a rural stream, showed a greater need for nutrient management than the other urban streams, highlighting the importance of controlling non-point source pollution in its vicinity for comprehensive water quality improvement. The water quality demonstrated a tendency to decline during the rainy season, underscoring the necessity for enhanced water quality management during this period. Among the tributaries, Yeongicheon, a rural stream, exhibited a heightened requirement for nutrient management compared to the remaining three urban streams, indicating that effective control of non-point source pollution in the surrounding areas is essential for the comprehensive water quality management of these tributaries. In addition, the use of Monthly Water Quality Index developed in this study is recommended to calculate the water quality index with monthly water quality data.

Characteristics and Predictive Analysis of Heavy Metal Pollution in Typical Municipal Solid Waste Landfill Soil

ABSTRACT Due to the excavation of landfill sites, the safe disposal of high-content humus soil and the control of secondary heavy metal pollution have become urgent issues to be addressed. Exploring the forms of heavy metals in humus soil is crucial for a comprehensive and accurate assessment of the characteristics and toxic effects of heavy metal pollution. The present study analyzed the pollution characteristics and ecological risks of heavy metals in humus soils obtained from three typical municipal solid waste landfills in Zhejiang Province, China. The results indicated elevated concentrations of Cu, Zn, Cr, and Pb in the three landfills, with maximum concentrations reaching 5041, 6093, 2756, and 3576 mg/kg, respectively. The RAC (Risk Assessment Code) Risk Index and Potential Ecological Risk Index methods indicate that Cd in landfills has a high ecological risk and high bioavailability. Five machine learning models of Logistic Regression (LR), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Support Vector Machine (SVM), and Multi-Layer Perception (MLP) were employed to predict the concentrations of heavy metals. The RF model showed the best performance for predicting Cu with an average Area Under the Curve (AUC) of 0.99, while the MLP model performed the best for predicting the concentration of Hg. This study provides a scientific basis and practical guidance for the effective control and resource utilization of heavy metal pollution in landfill humus soil.

Phytoplankton-environment dynamics in a tropical estuary of the northeastern Arabian Sea: a Generalized Additive Model (GAM) approach.

Phytoplankton are diverse photosynthetic organisms in estuarine ecosystems and sensitive indicators of environmental changes. This study employed Generalized Additive Model (GAM) to explore the impact of environmental variables on the abundance of six dominant phytoplankton species in the tropical Karanja estuary, India. Data were collected from five sampling stations between January 2022 and March 2023. The GAM model explained ≥ 55% of the variability in species distribution, predicting that the Karanja estuary provides a suitable habitat for these phytoplankton. Spatiotemporal predictions revealed higher abundances of Asterionellopsis glacialis, Coscinodiscus sp., Pseudo-nitzschia pungens, Skeletonema costatum and Thalassionema frauenfeldii during post-monsoon and lower in pre-monsoon. Conversely, Odontella sinensis thrived during pre-monsoon. Optimal growth conditions included a water temperature range of 24-32°C for O. sinensis, P. pungens and S. costatum, while chlorophyll-b concentrations between 1 and 20mg/m3 favored A. glacialis, O. sinensis, P. pungens, S. costatum and T. frauenfeldii. P. pungens, S. costatum and T. frauenfeldii exhibited broad salinity tolerance ranging from 10-40‰. Additionally, Coscinodiscus sp., P. pungens and T. frauenfeldii were found in environments with nitrate content of 0.1-1mg/L, while O. sinensis preferred silicate levels of 1-10mg/L. Notably, these species serve as indicators of eutrophication, providing insights into ecosystem health. This study represents the first application of GAM for exploring phytoplankton-environment interactions in India, offering critical data for water quality management, pollution control and food web preservation. Policymakers can use these findings to develop evidence-based regulations that support proactive coastal management, enhance estuarine resilience to climate stressors and ensure sustainable resource conservation.

Assessment model of ozone pollution based on SHAP-IPSO-CNN and its application

The problem of ground-level ozone (O3) pollution has become a global environmental challenge with far-reaching impacts on public health and ecosystems. Effective control of ozone pollution still faces complex challenges from factors such as complex precursor interactions, variable meteorological conditions and atmospheric chemical processes. To address this problem, a convolutional neural network (CNN) model combining the improved particle swarm optimization (IPSO) algorithm and SHAP analysis, called SHAP-IPSO-CNN, is developed in this study, aiming to reveal the key factors affecting ground-level ozone pollution and their interaction mechanisms. Firstly, an atmospheric dispersion model is utilized to predict the distribution concentration of VOCs emitted by enterprises in the park at the target monitoring stations based on the ozone generation mechanism. Then three mainstream machine learning models are compared for SHAP analysis to obtain the significance results of relevant features. Finally, the IPSO algorithm is combined with SHAP analysis to dynamically adjust the training features to optimize the performance of the CNN model. The model integrates atmospheric pollutants and related meteorological data to explore the nonlinear influence relationship of ozone formation in depth. The performance of the model is validated by the comprehensive evaluation indexes of R2, MAE and RMSE, and the results show that the present model outperforms the IPSO-CNN and SHAP-PSO-CNN models with the performance indexes of R2 of 0.9492, MAE of 0.0061 mg/m3 and RMSE of 0.0084 mg/m3. This study not only advances the understanding of ozone pollution formation mechanisms, but also provides an assessment of the impact of VOCs emissions from enterprises in the park, which provides empirical support for environmental management.

Fuzzy logic modelling of the pollution pattern of potentially toxic elements and naturally occurring radionuclide materials in quarry sites in Ogun State, Nigeria

The accumulation pattern of some inorganic pollutants in quarry sites around Ogun State was modeled using a Fuzzy comprehensive assessment (FCA). Potentially toxic elements (PTEs) and naturally occurring radionuclides materials (NORMs) were assessed from soil samples collected from ten quarry sites in three districts (Odeda, Ajebo, and Ijebu Ode) in Ogun State. Three (3) NORMs (40 K, 238U, and 232Th) were assessed using gamma spectrometer with a NaI detector while ten (10) PTEs (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were determined by digestion method using Inductively coupled plasma optical emission spectrophotometer. The FCA was used to evaluate soil contamination, and SPSS version 21.0 was used for statistical analysis. Concentration range of PTEs(mg/kg) and NORMs(Bq/kg) in all the site are: As (5.62 ± 0.85 – 15.93 ± 2.40), Cd (BDL—1.26 ± 0.60), Co (5.56 ± 1.34 – 27.25 ± 1.14), Cr (18.68 ± 1.54 -61.43 ± 6.33), Cu (12.40 ± 1.31—82.43 ± 7.94), Fe (15,035.00 ± 81.12 – 36,520.00 ± 292.20), Mn (168.97 ± 5.93 – 353.30 ± 20.84), Ni (5.63 ± 1.99- 25.54 ± 2.50),),Pb (4.44 ± 0.8 – 17.87 ± 2.80) and Zn (42.97 ± 413 – 147.00 ± 7.50); 40 K (76.78 ± 44.76—2647.88 ± 179.44), 238U (3.24 ± 1.82—55.42 ± 24.88),and 232Th (5.24 ± 3.90—244.36 ± 89.84). The results were modeled into a membership function matrix of three pollution classes. The FCA of NORMs revealed that 30, 10, and 60% of the sites were pristine, moderately polluted, and heavily polluted.In comparison, the FCA of PTEs confirmed 100% of the sites to be heavily polluted due to the accumulative effect of the PTEs. A high percentage of membership in the extremely impacted class is linked to a high concentration of Fe in all the sites due to the soil's geological structure and natural activities. At the same time, 40 K and 238U have high-impact membership in all the quarry sites. Based on the findings, there is a need for stringent pollution control measures, targeted monitoring of PTEs and NORMs and the development of region-specific environmental regulations to protect both public health and ecosystems.

Forest Mercury Deposition Observation in Chongqing: Evaluating Effectiveness of Mercury Pollution Control over the Past Decade in Southwestern China

Forest Mercury Deposition Observation in Chongqing: Evaluating Effectiveness of Mercury Pollution Control over the Past Decade in Southwestern China

Decline in Water Treatment Efficiency of an Estuarine Constructed Wetland over Its Operating Years

Estuarine constructed wetlands (ECWs) play a role as ecological barriers in the control of external pollution in lakes. Usually, ECWs show reduced water treatment efficiency after many years of operation compared to their initial performance. However, it is unclear how the water purification efficiency of an ECW changes over time. After over a decade of tracking analysis on an ECW, this study found that it indeed played a significant role in achieving water quality improvement effects. The average removal rates for total nitrogen (TN) and total phosphorus (TP) and the permanganate index (CODMn) were 36.2%, 26.7%, and 30.7%, respectively, with annual reductions of 1.6 t/a, 20.8 t/a, and 44.6 t/a. The surface hydraulic load is a critical indicator for the design and operational management of ECWs. The reduction loads of TP, TN, and CODMn increased with the rise in surface hydraulic load, indicating that this ECW project had certain advantages in treating large-volume water bodies. However, when strict CODMn treatment is needed, the surface hydraulic load should be reduced. During the high-efficiency period (2010–2015), the treatment effects on TN and TP were more than twice those during the degradation period (2016–2021), and the effect on CODMn was about 1.5 times greater. With increased operation years, the TN removal rate declined most rapidly due to pollutant accumulation and sediment release.

The synergies of air quality monitoring program: Information disclosure and pollution control.

To deal with the increasingly severe climate crisis and environmental pollution, China launched a nationwide real-time air quality monitoring program in three batches, a milestone moment in its environmental governance history. Using the time-varying difference-in-differences model, this study explores the synergies of this program across 284 cities from 2009 to 2019. The findings are as follows: (1) With environmental information disclosed, the national air quality monitoring program can reduce the outdoor fine particulate matter concentration by an overall effect of 3.31%, equivalent to an almost 1% reduction calculated by its average value. (2) This program can enhance public environmental attention and stimulate environmental practitioners' employment, thereby achieving a synergistic effect on air pollution reduction. (3) The pollution reduction effect is expected to be more pronounced in cities located in the southern and eastern regions, cities with higher population densities, and cities with favourable ventilation capabilities. (4) In response to air pollution problems, the public will adjust their daily consumption patterns to avoid potential health risks. As a result of the short-term behavioural changes, they will be more willing to pay for clean air by purchasing household air purifiers. This study highlights the considerable ecological and economic benefits of environmental information disclosure, thus further contributing to future eco-friendly and sustainable development.

Heterotrophic denitrification enhancement via effective organic matter degradation driven by suitable iron dosage in sediment.

The control of internal pollution was important throughout the restoration of the lake, especially the removal of sediment internal nitrogen. Experiments involving incubation were conducted in this study to investigate the effects of iron remediation on nitrogen in both water and sediment. Adding iron with varying dosage had different effects on the nutrients content and other properties of water and sediment in remediation. The higher the addition dosage of iron, the more iron ions were released into the interstitial and overlying water. The effect of 5% and 10% iron dosage on the interstitial and overlying water were more obvious, which can significantly increase the pH and decrease the ORP of the sediment, and significantly increase the TN and NH4+-N contents in overlying water. Nevertheless, higher iron addition dosage decreased relative abundance of the genera related to denitrification (Thiobacillus) and DNRA (Bacillus). The relative abundance of Anaerolineae was increased with the iron addition dosage, promoted the reduction of organic matter and iron cycle in sediment. The iron addition dosage of 2% had less effect on the overlying water quality, and promoted the nitrogen removal process by changing the abundance of microorganisms related to the sediment nitrogen cycle. This study provides essential information for internal pollution control of lakes and serves as a valuable reference for developing eutrophication management framework.

Effects of perfluorolauric acid exposure on intestinal microbial community and physiological health indicators in mice

The present study aims to investigate the effects of Perfluorolauric Acid (PFLA) on the gut microbiota community and the physiological health of mice. The experiment was conducted by setting a control group (CTRL) and an experimental group (PFLA), exposing mice to PFLA and observing changes in their gut microbiota community and physiological health indicators. The results showed that exposure to PFLA significantly altered the β diversity of the gut microbiota in mice, as evidenced by NMDS, PCoA, and PCA analyses, indicating a clear change in microbial community structure between the PFLA group and the CTRL group. Moreover, PFLA led to a decrease in α diversity of the gut microbiota, with certain specific species such as CryptoBacteroides significantly increasing in the PFLA group while Odoribacter_laneus decreased. In terms of physiological health, exposure to PFLA resulted in increased liver inflammation, lipid abnormalities, and caused histological changes in the colon, such as ulcerative colitis and damage to glandular structures. These findings suggest that PFLA has adverse effects on the gut microbiota community and physiological health of mice. This study can provide foundational data and references for the pollution control of PFLA.

Zeolite Nanoparticles: The Eco-Friendly Solutions for Environmental Contamination

Abstract: This review highlighted the innovative utilization of zeolite Nanoparticles (NPs) in various environmental applications, emphasizing their role in transforming waste materials into valuable resources. Zeolite-confined metal NPs, particularly Palladium (Pd), exhibit enhanced catalytic performance in the deep oxidation of light alkanes due to their unique interfaces and protective zeolite structures. Developing electrospun membranes incorporating cellulose acetate and nano-zeolites demonstrates promising potential for effective oil removal from wastewater, achieving up to 97% separation efficiency. The synthesis of silver NPs from Tilapia fish waste and their valorization within natural zeolites showcases an eco-friendly approach for ammonia removal and antimicrobial applications. Integrating nano-silicon and nano-zeolite treatments in combating salinity stress in medicinal plants highlights sustainable agricultural practices. This review emphasizes the multifaceted benefits of zeolite NPs in addressing urgent environmental challenges and promotes future research directions to optimize their applications in pollution control and resource recovery. Prospects include scaling up production methods, exploring novel composite materials, and investigating the long-term environmental impacts of these nanomaterials to enhance their practical applicability in diverse settings.

Integration of Total Maximum Daily Load (TMDL) and Environmental Flow Assessment (EFA) Concepts as an Adaptive Approach to Pollutant Loading Management in Asia: A Review

Water scarcity and pollution are escalating challenges in Asia, impacting ecological systems and human livelihoods. This paper reviews the integration of Total Maximum Daily Load (TMDL) and Environmental Flow Assessment (EFA) in water management to address the dual issues of water quality and quantity. TMDL focuses on regulating the number of pollutants entering water bodies to meet quality standards, while EFA ensures that enough water is available to support aquatic ecosystems. Their independent application, however, often leads to gaps—TMDL can overlook ecological needs, while EFA may neglect pollution control. The integration of these two frameworks offers a more holistic solution, especially in water-stressed regions like Southeast Asia, where moderate water availability is exacerbated by urbanization, industrialization, and agricultural runoff. Case studies from Malaysia, Indonesia, and China reveal the limitations of applying TMDL and EFA separately and underscore the necessity of addressing both ecological flow requirements and pollution limits. This paper identifies key pollutants such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), heavy metals, and total suspended solids (TSS), particularly in urban and semi-urban areas, and highlights the importance of tailoring strategies to the specific needs of different regions. By combining TMDL and EFA, policymakers can better manage pollutant loads, secure ecological health, and address Asia’s pressing water management issues. This review emphasizes the need for adaptable, integrated water management strategies that account for seasonal fluctuations, competing water demands, and regional water availability and pollution differences.

Assessing public support for air pollution mitigation and control policies: health, socioeconomic, and ideological predictors in an overburdened and vulnerable region of the U.S.

BackgroundThe San Joaquin Valley (SJV) in California is one of the most polluted regions in the U.S. This study examined favorability for air pollution mitigation policies, interventions, and identified predictors amongst region’s residents.MethodsA cross-sectional online survey asked about health status and conditions, self-protective behaviors, attitudes toward air pollution recommendations, air quality information knowledge and mitigation behaviors, as well as whether their views were favorable or unfavorable towards policy and interventions. EuroQOL-5D-3L was utilized to estimate quality-of-life distribution equity and air pollution policy favorability.ResultsA total of 310 adults residing in the SJV participated in the survey. The mean age was 42.90 years, with 34% having asthma. People with asthma reported the lowest health-related quality of life (HRQoL) compared to other air pollution “sensitive” groups. Concerns included the costs, charge and attributes of adopting hybrid or electric vehicles. Residents supported air pollution control and public space preservation, with socioeconomic factors and health state being significant predictors. Left-wing ideologies favor policies charging polluters, controlling emissions, and preserving public spaces, whereas right-wing views negatively predict support for electric vehicle charges and local organization interventions.ConclusionsResults may help air pollution control policymakers, public health agencies, environmental justice organizations, and the health equity research community understand the reasons for differential responses to air pollution interventions and mitigation efforts. This new knowledge could assist stakeholders in recommending sustainable and cost-effective interventions for improving air quality, elicit behavior change, and climate change adaptation in the region.

Ocean current modulation of the spatial distribution of microplastics in the surface sediments of the Beibu Gulf, China.

Microplastic pollution, a major global environmental issue, is gaining heightened attention worldwide. Marginal seas are particularly susceptible to microplastic contamination, yet data on microplastics in marine sediments remain scarce, especially in the Beibu Gulf. This study presents a large-scale investigation of microplastics in the surface sediments of the Beibu Gulf to deciphering their distribution, sources and risk to marginal seas ecosystems. The results reveal widespread microplastic contamination, with an average abundance of 391 ± 27 items/kg in sediments. The spatial variability of microplastic abundance was significant, with lower levels in the western Beibu Gulf and higher concentrations in the northeastern and southeastern regions. The spatial distribution of microplastics was largely driven by geological features, hydrodynamic conditions, and human activity, with minimal influence from local environmental factors such as water depth, sediment grain size, organic carbon content, and sediment types. The pollution load index (PLI) suggests a low level of microplastic contamination, but the polymer hazard index (PHI) identified a high ecological risk, likely due to the presence of PVC, a polymer with higher chemical toxicity. Our findings highlight the significant role of hydrodynamic processes in determining microplastic distribution in the Beibu Gulf. These insights enhance our understanding of microplastic dispersal and its governing factors in semi-enclosed marginal seas, providing foundation for targeted pollution control strategies.

Quantifying Socio-Regional Variability via Factor Analysis over China: Optimizing Residential Sector Emission Reduction Pathways

Policy synergy, the evidence-based coordination of public policies, can aid in more rapidly achieving air pollutant and carbon dioxide (CO2) emission reduction targets. Using logarithmic mean Divisia index (LMDI) decomposition, coupling coordination degree (CCD), and geographically and temporally weighted regression (GTWR) models, we analyzed the emission characteristics, drivers, and reduction pathways of residential air pollution across 30 Chinese provinces from 2001 to 2020. The southern provinces produced more air pollution than the northern provinces, with the gap widening after 2015. In the residential sector, energy emission factors (LMDI decomposition result, 686,681.9) and population size (14,331) had greater impacts on air pollutant emissions than the energy structure, energy intensity, synergies, or GDP per capita. The GTWR analysis of the CCD mechanism indicated that hydroelectricity and urbanization enhanced coupling coordination in the southeast. Meanwhile, in the west, coupling coordination was improved by R&D investment, government spending on industrial pollution control, electricity consumption, per capita cropland, temperature, and urbanization. This analysis provides a valuable reference for optimizing emission reduction strategies.

Impact of Environmental Pollution on Infectious Disease Incidence: Challenges and Preventive Solutions: A Review Article

Background: Environmental pollution poses serious threats to public health and contributes significantly to the spread of infectious diseases. This study examined the effects of air, water, and soil pollution on the incidence of infectious diseases while proposing preventive measures and relevant public policies. Methods: This systematic review was conducted using Google Scholar, PubMed, Science Direct, and Springer Link databases covering 2020 to 2024 to investigate the link between environmental pollution and infectious disease spread. Reputable scientific articles from reliable databases were reviewed to ensure comprehensive coverage. Results: Twenty six selected studies indicate a significant association between environmental pollution—particularly air, water, and soil pollution—and the increased incidence of infectious diseases. Conclusion: Environmental pollution has extensive and serious impacts on human health and the spread of infectious diseases. Effective pollution control and reduction can play a crucial role in lowering infectious disease rates. Further research is essential to deepen our understanding of this issue and develop effective strategies.

Advanced treatment of first flush roof runoff via a dry-wet polymorphic constructed wetland system: Performance and mechanistic insights.

Controlling runoff pollution is crucial to improving ecological environments in the context of urbanization and climate change. However, a significant research gap remains in the treatment and reuse of roof runoff, particularly during the first flush. To address this, a novel dry-wet polymorphic constructed wetland (DWP-CW) system was developed to purify first flush runoff efficiently and reliably. The performance and stability of the DWP-CW system were evaluated under varying conditions, including rainfall intensities, pollution load levels, and antecedent dry days (ADDs). The purification mechanisms and pollutant metabolism were further analyzed using bioinformatics. Results demonstrated that the DWP-CW system achieved excellent pollutant removal efficiencies, with average removal rates exceeding 99% for chemical oxygen demand (COD) and ammonia-nitrogen (NH3-N), and stable removal rates above 80% for total nitrogen (TN) and total phosphorus (TP). The dominant aerobic microbial community played a key role in the system's purification process, while the superior water-retention capacity of the upper sandy soil layer provided a favorable environment for microbial survival during ADDs. This study offers robust theoretical support for practical application of DWP-CW systems in runoff pollution control.

Assessing the Effectiveness of Nigeria's Legal Framework in Controlling Oil and Gas Pollution: Challenges and Recommendations

Oil and gas pollution poses significant environmental and health risks to communities in Nigeria, particularly in the Niger Delta region. Despite the devastating impacts of pollution, Nigeria's legal framework for controlling oil and gas pollution has been criticized for being inadequate and ineffective. This article undertook a critical appraisal of the legal measures for the control of oil and gas pollution in Nigeria. The article examined the relevant international, regional, and national laws and policies governing oil and gas pollution in Nigeria, including the International Convention on Oil Pollution Preparedness, Response and Cooperation, the African Convention on the Conservation of Nature and Natural Resources, and the Nigerian Oil and Gas Industry Content Development Act. The article critiques the strengths and weaknesses of these laws and policies, highlighting gaps and inconsistencies that hinder effective pollution control. The article also analyzed the institutional framework for pollution control in Nigeria, including the roles and responsibilities of regulatory agencies such as the National Oil Spill Detection and Response Agency and the Department of Petroleum Resources. The article argued that while these agencies have made efforts to control pollution, they are often hindered by inadequate funding, lack of capacity, and conflicting mandates. Furthermore, the article examined the impact of oil and gas pollution on local communities in Nigeria, highlighting the human rights implications of pollution and the need for effective remedies and compensation. The article concluded by proposing recommendations for strengthening the legal framework for pollution control in Nigeria, including the adoption of more stringent regulations, the enhancement of institutional capacity, and the provision of effective remedies for affected communities.

Spatiotemporal estimates of anthropogenic NOx emissions across China during 2015-2022 using a deep learning model.

As one of the significant air pollutants, nitrogen oxides (NOx = NO + NO2) not only pose a great threat to human health, but also contribute to the formation of secondary pollutants such as ozone and nitrate particles. Due to substantial uncertainties in bottom-up emission inventories, simulated concentrations of air pollutants using GEOS-Chem model often largely biased from those of ground-level observations. To address this issue, we developed a new deep learning model to simulate the inverse process of the GEOS-Chem model. This framework was applied to improve the total anthropogenic NOx emission intensity over a five-year period (2015-2019), and then to predict anthropogenic NOx emission intensity for 2020-2022. The deep learning model showed higher R2 value (0.94) based on 10-fold cross-validation, indicating that the model effectively captured spatial features and patterns. Then, NOx emission intensity was calibrated based on the new framework using high-resolution NO2 concentration dataset instead of the simulated NO2 levels derived from GEOS-Chem model. Overall, the top-down inversion result was in agreement with the bottom-up emission inventory at the spatial scale. The top-down emission fluxes were lower in high-emission regions such as central China, Beijing, Shanghai, the Pearl River Delta, and the central part of Liaoning, while posterior estimates were higher in regions with lower prior emission intensity. The posterior NOx emission intensity suggested that some major regions such as Beijing-Tianjin-Hebei (BTH) (-56.4 %) and Pearl River Delta (PRD) (-52.5 %) experienced dramatic NOx emission intensity decreases from 2015 to 2022, whereas some remote regions such as Tibetan Plateau remained relatively stable. This research contributes to the timely tracking of changes in pollutant emission and aids in the formulation of more effective and relevant pollution prevention and control policies.

Advances on jarosite residue detoxification and reutilization: a review.

Jarosite residues are typical hazardous waste byproducts generated during the iron removal process in hydrometallurgical solutions. The jarosite process is widely used for iron removal in zinc hydrometallurgy; jarosite disposal has become a significant barrier to sustainable development in the industry. During this process, jarosite residues entrain and co-precipitate with heavy metals, which are hazardous but valuable. To better understand jarosite residue pollution control and circular recycling, we reviewed related research conducted over the past two decades, analyzed their characteristics, discussed state-of-the-art technologies for jarosite residue detoxification and reutilization, and proposed feasible suggestions for jarosite circular reutilization. We hope that this review helps solve the problem of jarosite residues and promote the sustainable development of the zinc hydrometallurgical industry.