Search

The Arctic region, including Svalbard, faces unique environmental challenges from the presence and persistence of organochlorine pesticides (OCPs), pollutants known for their long-range atmospheric transport and potential local sources. In Svalbard, the melting of sea ice and glaciers due to climate change may release OCPs trapped over decades, while human activities in the area could contribute additional local contamination. This study aimed to identify and quantify different sources of OCPs in soil and marine sediments at Svalbard. Samples were collected from Kongsfjorden, Rijpfjorden, and in Ny-Ålesund. The concentrations of 23 OCPs in sediments sampled were in the range of 0.36-0.90 ng/g, which were lower than those in the soils from Ny-Ålesund (0.28 ng/g to 3.6 ng/g). The highest OCP levels were detected at locations near the research station in Ny-Ålesund, where local contamination from research activities, mining, and dumpsites could occur. Hexachlorobenzene (HCB) were the most prominent compound, followed by various DDTs and HCHs. Dignostic ratios and the Positive Matrix Factorization (PMF) model were employed to determine the primary sources of OCPs. The results from modeling showed that historically used pollutants were the primary contributor, accounting for 90% of OCPs present, while recently input OCPs were a minor contributor. However, newly input pollutants significantly contributed to HCHs (43%). It is suggested that the contribution of legacy OCPs mainly comes from the melting of sea ice and glaciers. This was especially true for Rijpfjorden (95%), while it was also significant for Kongsfjorden (55%). The local contamination and fresh inputs played a substantial role in the area near the research station in Ny-Ålesund. The study emphasizes the importance of secondly source, especially the role of melting sea ice and glaciers as well as local contaminations as sources of OCPs in Svalbard's marine sediment, which highlight the urgent need to address the impact of climate change on the Arctic environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Ultrafine particles (UFP), commonly expressed as particle number concentrations (PNC), have been associated with harm to human health yet are currently not regulated or routinely monitored in many places. This has limited the potential for studies of health effects of long-term exposure to UFP. The present study aims to understand the spatial and temporal variation in façade-level UFP exposures in Copenhagen, Denmark. We measured PNC at the façades of 27 residences across the city for approximately 72 h each in two campaigns and continuously at an urban background reference site for twelve consecutive months, using portable monitors (miniature diffusion size classifiers [DiSCminis]). We estimated annual means at the residential sites based on temporal adjustment using reference site data. Furthermore, we co-located the DiSCminis at a regulatory monitoring station on three occasions and compared daily means from our reference site to those from seven fixed-site monitoring stations throughout the city. Annual mean PNC at the reference site was 4715 (SD of hourly mean: 3001) pt/cm 3 , while annual means at 27 residences were slightly higher with a mean of 5201 pt/cm 3 (SD: 807), ranging between 3735 and 6588 pt/cm 3 . The two individual adjusted campaign-specific means at 27 residential sites were weakly correlated (Spearman's correlation 0.11) and had an intra-class correlation coefficient of 0.06 (95%-confidence interval: -0.18, 0.28). Daily PNC at the reference site was highly correlated (R = 0.64-0.84) with PNC monitored at seven fixed-site stations throughout the city. We observed a seasonal trend at the reference site with the highest PNC in spring. Our measurement campaign revealed that façade-level PNC at residences in Copenhagen in 2021-2022 was relatively low with small spatial variability. The large variability in time suggests possibly longer and more frequent measurement campaigns to obtain more stable annual averages. Our study illustrates the challenges of UFP long-term exposure assessment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mining operations contribute to higher environmental contaminant levels, such as particulate matter (PM) hosting potentially toxic elements (PTE). This study aimed to comprehensively characterise atmospheric PM in an environment impacted by former tungsten-tin mining exploration at Regoufe mine (Arouca, Portugal). Although this is a deactivated mine, its location near population clusters and integration into a Geopark belonging to the "World Geoparks Network" with frequent presence of hikers highlight the importance of air quality monitoring to keep its Geopark classification. A seasonal and cumulative sampling approach was used, with samples collected over a seasonal period, between April 2022 and April 2023, through passive sampling, wet and dry sedimentation, and air mass filtration. All samples were analysed using SEM-EDS for detailed imaging. Samples from wet deposition and filtration were also analysed with ICP-MS to determine the concentration of the inorganic elements. The PTE determined in the atmospheric particulate matter of the studied area occurs in variable concentrations as a function of the sampling period. The mineralogy of the PM sampled includes Sn- and W-minerals, pyrite, quartz, phosphates, sulfates, and As-oxides. These materials are typical in the site's soils, suggesting their resuspension by the wind and transported to nearby areas. Angular to sub-angular dense particles indicate limited transportation, depositing closer to their emission source. The smaller particles (<25 μm) tended to be angular with sharp edges. Our results emphasise the importance of monitoring potentially toxic elements in atmospheric particulate matter of abandoned mining areas for developing mitigation strategies to reduce impacts on human health and surrounding environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Elucidating the chemical composition, sources, and health risks of fine particulate matter (PM 2.5 ) is crucial for effectively preventing and controlling air pollution. This study collected PM 2.5 samples in Linyi from November 10, 2021, to October 15, 2022, spanning the period of the 2022 Winter Olympics and Paralympics. The analysis focused on seasonal variations in the chemical composition of PM 2.5 , including water-soluble ions, inorganic elements, and carbonaceous aerosols. Results from the random forest model indicated that control measures during the Olympics and Paralympics reduced PM 2.5 concentrations by 21.5% in Linyi. Organic matter was the dominant component of PM 2.5 , followed by NO 3 - , SO 4 2- , and NH 4 + . Among secondary inorganic ions, SO 4 2- exhibited the highest concentration in summer, while NO 3 - and NH 4 + showed the lowest concentrations. The inorganic elements S, K, Fe, and Si had high mean annual concentrations, underscoring the need for targeted control measures for plate production, bulk coal burning, and biomass combustion in Linyi. The organic carbon (OC) to elemental carbon ratio (17.7-20.5) in Linyi was high, highlighting the importance of addressing secondary OC pollution. According to the positive matrix factorization model, coal burning, and the secondary formation processes of sulfate and nitrate were the dominant sources of PM 2.5 . Backward air mass trajectories revealed substantial contributions from the southeastern, local, and southwestern regions of Linyi. This suggests the need for enhanced regional joint prevention and control efforts between Linyi and neighboring cities, such as Rizhao and Jining in Shandong Province, as well as northern cities in Jiangsu Province. The highest non-carcinogenic and carcinogenic risks (CRs) were associated with As. coal burning posed significant noncarcinogenic risks and a moderate CR, contributing 41.7% and 44.0% of the total health risk, respectively. These findings are crucial for developing effective air pollution prevention and control strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Marine sediments are recognized as major sinks for microplastics, including remote areas which were previously considered "plastic-free". The understanding of microplastic dynamics in marine sediments is however limited due to the numerous pelagic and benthic pathways involved, and how these are influenced by physico-chemical interactions with the particles. European continental shelves border densely populated areas and face a high risk of microplastic contamination. In this study we quantified microplastics in soft-sediments of European coastal seas and characterized their polymer composition separating surface sediments from deeper layers. We then analyzed the influence of water column and sediment properties on spatial variability of seabed microplastics and investigated the relationship with macrofauna communities. A higher proportion of negatively buoyant polymers in surface sediments (0-1 cm) across stations was explained by seawater salinity and sediment microalgal detritus, highlighting the role of riverine input and possibly the formation of hetero-aggregates in defining polymer deposition. Additionally, we found that seawater temperature influenced polymer composition in deeper sediment layers (0-3 cm), likely together with biological activities performed by macrobenthos such as ingestion and burial. Finally, we demonstrate that seabed microplastics contribute to the spatial variability in macrobenthos, highlighting that marine ecosystem functioning effects of microplastic pollution are likely mediated via the benthos., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Contamination of water resources with mixtures of organic micropollutants (OMP) including pesticides, pharmaceuticals, and industrial chemicals is a serious threat to aquatic organisms and human health. Long-term exposure to such pollutants may cause detrimental effects even at very low concentrations. Water resources in urban agglomerations in low- and medium-income countries may be under particular pressure due to high population densities, significant industrial activities, and limited water treatment and management resources. In these areas, many inhabitants directly rely on healthy urban water resources. Using the agglomeration of Lahore, Pakistan, as a case, we studied the occurrence, spatial distribution, and toxic risks of OMP mixtures in different urban water resources using target screening with liquid chromatography high-resolution mass spectrometry. In total, 266 of 576 target analytes were detected in at least one of the 200 samples taken from groundwater, canals, River Ravi and drains within the urban agglomeration. Notably, very high concentrations ranging from 10 to over 100 μg L -1 were found for highly toxic pesticides including several fungicides such as picoxystrobin, the transformation product phthalamic acid, and imazalil, the insecticide etofenprox but also industrial chemicals stemming for example from traffic such as 2-naphthalene sulfonic acid. Our study revealed high toxic risks particularly for invertebrates, fish and algae, with etofenprox as a dominant risk driver. This compound is extensively used in Lahore to control insect vectors of malaria and dengue fever in the urban agglomeration. Mixture risks were assessed using a toxic unit (TU) approach based on organism group specific effect concentrations, complemented with a risk quotient (RQ) approach using the lowest predicted no effect concentrations (PNECs). Acute and chronic risk thresholds were frequently exceeded, often by many orders of magnitude. These very high mixture risks strongly exceed those with previous studies in Europe, Africa and South America., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Ozone pollution was widely reported along with PM 2.5 reduction since 2013 in China. However, the meteorological drivers for ozone varying with different regions of China remains unknown using explainable machine learning, especially during the COVID-19 pandemic. Here we first analyzed spatiotemporal variations of PM 2.5 and ozone from 2015 to 2022 in eleven urban agglomerations of China. PM 2.5 decreased in all regions, with the largest drop in Beijing-Tianjin-Hebei (BTH). In contrast, ozone declined initially but rose during the pandemic in most regions, especially in Cheng-Yu. Probability density curves showed pronounced increase (24.7%) and slight change in the proportion of PM 2.5 and ozone meeting the pollution criterions during the pandemic, respectively. Leveraging Random Forest with SHAP analysis, we further established ozone models in typical urban agglomerations with good performance (CV-R 2  = 0.80-0.90; CV-RMSE = 8.52-19.20 μg/m 3 ) during the pandemic, and compared their relative importance of meteorological variables. Particularly, temperature and incoming shortwave flux at top of atmosphere were identified with high importance in high-ozone regions such as Middle Plain and BTH. Increasing importance of PM (e.g., PM 10 ) was found in southern China, e.g., Yangtze River Delta and Pearl River Delta regions. The western China was characterized with more importance of meteorology, especially in Tibet. Surface albedo and sensible heat flux from turbulence were noted distinctively with high importance in Tibet, partly due to their impacts on ozone formation by generating heat source and sink. In addition, sea level pressure (SLP) was revealed with the highest importance (25.2%) in Cheng-Yu, consistent with the fact that synoptic patterns characterized by SLP field could affect ozone pollution in Sichuan Basin. Our results not only provide an understanding of meteorological factors in regional ozone formation in China, but also highlight the feasibility of explainable machine learning in ozone studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) are toxic and persistent pollutants that raise concerns due to their accumulative characteristics in the environments and biota. Atmospheric PCDD/Fs can enter various recipient environments and impact the entire ecosystem, thereby arousing more attention. Dry deposition is deemed the dominant migration pathway of atmospheric PCDD/Fs owing to their predominant distributions in the particulate phase. So far, however, there is no universally accepted method and device for dry deposition sampling. Here, we selected two widely used dry deposition samplers that work in different modes, water surface sampler (WSS) and wet-dry deposition sampler (WDDS), and investigated their differences in dry deposition sampling of PCDD/Fs. The average monthly total (∑ 17 PCDD/Fs) dry deposition fluxes (F P ) in the particulate phase measured with the WSS and WDDS were 314 ± 158 pg/m 2 -day (36.6 ± 24.6 pg I-TEQ/m 2 -day) and 108 ± 39.4 pg/m 2 -day (11.4 ± 5.21 pg I-TEQ/m 2 -day), respectively. The difference between flux values indicated their collection efficiencies and artifacts during the sample collection. Higher dry deposition fluxes were measured in winter. This was mainly due to higher atmospheric levels of PCDD/Fs in colder months. The highest and lowest values of PCDD/Fs in both samplers were observed for OCDD and 2,3,4,6,7,8-HxCDF, respectively. This could indicate parallel collection characteristics of both samplers. A high-volume air sampler was used simultaneously with the WSS to determine the ambient air concentrations. Then, dry deposition velocities (V d ) were calculated by dividing the dry deposition fluxes (F p ) by the particulate phase concentrations (C p ) for each PCDD/F congener. The mean dry deposition velocity for PCDD/F congeners was determined with the WSS and WDDS 1.71 ± 0.88 cm/s and 0.64 ± 0.39 cm/s, respectively. Furthermore, the study underscored that water surfaces and shorter sampling periods provided more reliable values for particulate PCDD/F deposition than steel surfaces with prolonged exposure due to the degradation and volatilization effects observed on the latter., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The Western Himalayan mountains, with several riverine systems, are considered one of the most fragile environments in the world. Among them is Beas, a primary river that provides essential ecosystem benefits to thousands of indigenous people in North India. One of the major pollutants, microplastics (MPs), are ubiquitous contaminants, yet their occurrence in the Beas and ecological risk factors remain largely unexplored. Due to extensive tourism and urban-related burdens, the usage and release of enormous amounts of plastics and MPs into the Beas are apparent. Here, we investigated the extent of MPs pollution and subsequent environmental risks in water and sediments from Beas along a stretch of 300 km. Our results showed that MPs were abundant and widely distributed, with the abundance range (mean ± SE) being 46-222 (112.27 ± 12.43) items/L in water and 36-896 (319.47 ± 49.25) items/kg in sediment samples. We found significant differences in MPs' abundance in water but not sediments among the five sampling sites. There was a significant positive correlation between population size and the abundance of MPs, with the highest abundance in populated Kullu and the lowest loads at the remote Dhundi Glacier. Fibers and film were common morphotypes; most items measured <1 mm. Of the eleven polymers identified, the majority were polyethylene. The pollution load index ranged up to 4.99 (low-risk category); however, the polymer hazard index exceeded 1000 (highest-risk category), and the potential ecological risk index was 13,761 (extreme-risk category) at selected sites. This study fills a crucial knowledge gap and raises concerns about the possible impact on human health, as many riparian residents depend on Beas as their primary source of potable water. Our findings may assist governmental agencies in formulating comprehensive eco-friendly policies and advancing environmentally sustainable strategies in vulnerable locales adjoining the Beas waterway., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) contamination was investigated along a freshwater-seawater continuum from Chumphon River to the Gulf of Thailand. The vertical distribution in the water column and contamination in green mussels were also studied. MPs were detected in all water samples and sediment samples. Furthermore, MPs were detected in 75% of the green mussels. A higher abundance of MPs was observed in the river system than in the coastal region, indicating that river runoff associated with inland human activities is the major sources of MPs in the coastal regions and cultured green mussels. In the water column, a polymer gradient varying with depth existed where low-density particles decreased from surface to subsurface and sediment while high-density particles exhibited the opposite pattern. Polymers in surface and subsurface water were predominantly composed of low-density polyethylene, polypropylene, and polystyrene particles. However, sediment samples were equally dominated by those mentioned low-density polymers and high-density polyethylene terephthalate, polyamide, rayon, and cotton particles. Furthermore, fibers were the most common shape found in water, sediment, and mussel samples representing 95% of all particles in river water samples and were evenly distributed throughout the water column regardless of density. However, only shorter fiber (mostly <1 mm) was detected in green mussel samples similar to their living environment. Blue, black and white particles dominated all samples. During the tidal cycle, half of the MPs entering the Gulf of Thailand returned to the river during high tide. This backflow predominantly comprised small fibers and low-density polymer MPs. The average daily load of MPs from Chumphon River to the Gulf of Thailand was 3.33 × 10 2 million items/day., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Narainrit Chinfak reports financial support was provided by East China Normal University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Contaminants of emerging concern (CECs) are ubiquitous in aquatic environments and pose a range of biological effects including endocrine disruption. Yet, knowledge of their occurrence in wildlife including seabirds remains scarce. We investigated the occurrence of selected bisphenols, benzophenones, phthalate metabolites, benzotriazoles, benzothiazoles, parabens, triclosan, and triclocarban in plasma of 18 breeding female common eiders (Somateria mollissima) from an endangered population in the Baltic Sea as most of these CECs have never before been examined in eiders. We sampled blood at the start (T1) and end (T2) of incubation to investigate concentration changes during incubation. As early- and late-breeding eiders tend to differ in how they finance reproduction (local vs stored nutrient reserves), we compared early and late breeders to assess whether CEC concentrations differed by breeding phenology. Of the 58 targeted CECs, 21 were detected in at least one female, with bisphenol A (BPA) and benzophenone-3 (BzP-3) occurring most frequently (T1: 78% and 61%; T2: 61% and 67%, respectively), while mono(2-ethyl-1-hexyl) phthalate (mEHP), BPA, and monoethyl phthalate (mEP) were detected in the highest concentrations (median concentrations 27.1, 12.7, and 11.2 ng/g wet weight, respectively, at T1). No CEC concentrations differed between early and late incubation. Late breeders had significantly higher concentrations of BzP-3, monomethyl phthalate (mMP), and mEP during early incubation (4.55 vs 1.24 ng/g ww, 7.05 vs 3.52, and 11.2 vs < limit of detection (LOD), respectively) and significantly higher concentrations of mMP and mEP during late incubation (6.16 vs 

The nationwide prevalence of brownfields, with often unknown types and quantities of subsurface chemical contaminants, highlights the need for rapid, cost-effective, and noninvasive methods to reduce routes of exposure. In post-industrial cities such as Detroit, Michigan, anthropogenic volatile organic compounds (VOCs), known to negatively impact human health, are typically detected at brownfields through conventional methods, e.g. screening soil, and groundwater. Recently, the method of phytoscreening-the chemical analysis of plant tissues to provide evidence for belowground contamination-has become a viable alternative to conventional methods. However, few studies have been designed to directly compare conventional and plant-based methods of detecting VOCs. To fill this knowledge gap, we sampled and compared the concentration of six VOCs including BTEX, PCE, and TCE detected in conventional media (soil, soil vapor, groundwater, sewer vapor) and different plant tissue (tree core, leaf, root, shoot) at two brownfields sites in Detroit: an abandoned gas station with a leaking underground storage tank, and a former dry cleaning facility. Our results suggest that the concentrations of VOCs detected in plants are similar to or in some cases greater than conventional methods and can differ across the growing season. For example, leaves and roots detected, on average, a higher concentration of VOCs compared to shoots and tree cores, however, TCE and PCE were generally in higher concentrations in soil and soil vapor. Moreover, the frequency at which conventional versus phytoscreening methods failed to detect VOCs was similar at one site and higher at another, suggesting that phytoscreening may yield fewer non-detects at known sites of contamination. While additional work is needed to understand the relationship between concentrations of VOCs detected in soil versus co-located plant samples, our results suggest that phytoscreening may be a viable and reliable method to detect belowground chemical contaminants while reducing screening times and cost, and increasing access to private property., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Imidacloprid (IMI), a leading neonicotinoid insecticide, is widely used in China. Nevertheless, owing to its high toxicity to pollinators, regulatory scrutiny of its usage has increased in recent years. Despite this, no relevant issues have been announced in China, and its usage continues to rise. In this study, we systematically reviewed the development history, pollution characteristics, and environmental problems associated with IMI in China, which is imperative to promote its green development. The results show that most IMI products (97.1%) in China are registered for agricultural use. Owing to its extensive use and strong migration ability in different environmental matrices, IMI has been broadly detected in multiple environmental media. The average detection rate (DR) of IMI in soils, ambient water, and sediments were 90.7%, 81.3% and 84.5%, respectively, and the corresponding concentrations were 54.6 ± 83.8 ng/g dry weight (dw), 32.8 ± 103 ng/L, and 1.7 ± 2.9 ng/g dw, respectively, indicating high IMI abundance in multiple environmental media in China. The spatiotemporal distribution of IMI was generally determined by its application modes, transport, and degradation rates. IMI is commonly overused in China, leading to the development of high IMI resistance in many pests, and a high DR of IMI in food, drinking water, and human bodies. To alleviate IMI pollution in China, the joint efforts of the government, farmers, and scientists are necessary, including but not limited to formulating laws and regulations, strengthening governmental supervision, improving farmers' knowledge of IMI use, and promoting technological innovation in IMI and application methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Marine anthropogenic litter (MAL) pollution is a growing concern in coastal environments. These ecosystems are home to rich biodiversity but face significant challenges due to the accumulation of plastics and other solid waste, compromising the region's natural aesthetics and environmental health. This study investigates how marine pollution and the accumulation of MAL impact these ecosystems. We use the burrowing owl (Athene cunicularia) as an example to illustrate the potential risks associated with this pollution, especially for those species that nest near coastal regions along the Brazilian Amazon coast. At Atalaia Beach, the data collected revealed a significant diversity of MAL, totaling approximately 532 items. Among them, styrofoam and foam were the most representative, with 33.08% and 21.05%, respectively, totaling 54.14% of the recorded MAL. The distribution of these materials indicates a correlation with human activities, especially the use of plastics for fishing and recreation. Notably, styrofoam and foam were frequently found in burrowing owl burrows, highlighting the use of MAL around nests and the potential risks this plastic material poses to the species' nesting and rearing of their chicks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Vehicle emissions are recognized as a primary source of particle-phase polycyclic aromatic hydrocarbons (PAHs), significant contributors to the hazardous properties of PM 2.5 . This study investigates the profiles of PAHs through measurements conducted in a tunnel and an urban roadside environment in 2020. We quantified real-world vehicle emission factors for mixed fleets in the Zhongshu tunnel in Guizhou, southwest China, and found that the total PAHs had an emission factor of 8.15 μg veh -1 km -1 , with higher factors observed for high-ring PAHs. Additionally, we analyzed concentrations of 15 PAHs at a roadside environment in Hefei, southern China, with an average concentration of 23.81 ng/m 3 . PAHs with 4, 5, and 6 rings comprised 80% of total PAHs at the roadside and 87% in the tunnel. Gasoline emissions were the predominant source in both the tunnel and roadside environments, supplemented by non-tailpipe emissions, catering, domestic cooking, and asphalt from road surfaces. Notably, while the total toxicity equivalent concentration of Benzo[a]pyrene (BaP) significantly exceeded the World Health Organization (WHO) guidelines of 1 ng/m 3 , the presence of additional compounds such as Dibenzo[a,h]anthracene (DahA) markedly increased the toxicological impact of PM 2.5 from vehicle emissions. Therefore, it is essential to implement targeted pollution control strategies in central urban areas that address not only the overall concentration of PAHs but also their specific toxic contributions Continuous monitoring and assessment of PAHs in the urban environment are indispensable for effectively reducing their health impacts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Mineral exploitation is one of the human activities that seriously affect freshwater ecosystems. It is of great significance to study the impact of mining on the α and β diversity of macroinvertebrates. This study reveals the response of taxonomic and functional α and β diversity of macroinvertebrates to mining activities in the Luanchuan molybdenum mining area. A total of 40 sets of macroinvertebrates, sediment and water samples in the Taowan North River (TR), Yu River (UR) and Hongluo River (HR) in the molybdenum mining area were collected. The results show that: 1) the mining activities led to obvious differences in the environmental factors of the three rivers. The heavy metals in the sediments and water bodies of TR and UR showed different degrees of exceedance, while there was no exceedance of heavy metals in HR; 2) The taxonomic and functional α diversity was much lower in the TR and the UR than in the HR. The concentrations of heavy metals in sediments and water bodies were significantly negatively correlated with the taxonomic and functional α diversity; 3) Mineral extraction resulted in significant differences in macroinvertebrate β diversity among the three rivers. The taxonomic and functional β diversity of the macroinvertebrate communities in TR and UR was much higher than that in HR. The turnover and nestedness of functional β diversity showed significant differences. Functional β diversity was more obviously affected by heavy metal exceedance than taxonomic β diversity. Nestedness were more sensitive to exceedance of heavy metals than turnover. The results of this study can provide a theoretical basis for ecological restoration and protection of rivers in mining areas., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Na Zhao reports financial support was provided by National Natural Science Foundation of China. Na Zhao reports financial support was provided by Henan Provincial Science and Technology Research Project. Ruixue Cao reports financial support was provided by Henan Provincial Science and Technology Research Project. Na Zhao reports financial support was provided by Young Backbone Teacher Project of Henan University of Science and Technology. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Source identification of atmospheric microplastics (MPs) is crucial for the development of mitigation policies. Compared with wind directions or backward trajectories of air masses, the potential source contribution function (PSCF) analysis identifies more comprehensive sources of atmospheric particles. However, conducting PSCF analysis requires hourly pollutant concentration data, which cannot be met by the atmospheric MPs abundance obtained through commonly used methods. In this study, total suspended particles (TSP) samples were collected hourly and the concentrations of atmospheric polyethylene terephthalate (PET) were detected using a liquid chromatography-tandem mass spectrometry. Atmospheric concentrations of PET MPs were 112.9 ± 39.04 ng/m³ (average ± SD). Based on the hourly backward trajectories of air masses and the varied PET concentrations at the sampling site, potential sources of atmospheric PET were identified by PSCF analysis. The backward trajectory-based method indicates that atmospheric PET of the target site in this study primarily originates from dry farmlands. In comparison, both the residential areas and the dry farmlands were identified by PSCF as major sources of atmospheric PET at the receptor site. In contrast, both the backward-trajectory based method and PSCF analysis indicate that TSP mainly originates from the dry farmlands near the sampling site. This indicates that atmospheric PET in urban areas may have different sources from those of TSP, and PSCF is a suitable method for identifying sources of atmospheric PET., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Assessing persistent organic pollutant (POP) levels across regions helps evaluate environmental health and determine ecological risks. As an apex predator, the common dolphin (Delphinus delphis) serves as an excellent model for understanding POP exposure and impact in Eastern North Atlantic marine ecosystems. In this study, we collected biopsy samples of common dolphins in two ecoregions, the pelagic system of Madeira Island (Portugal) (n = 30) and in the continental shelf of Northwest Portugal (n = 14) to analyse organochlorine concentrations (PCBs, DDTs, Mirex, HCB) from their blubber. For both ecoregions, PCBs comprised the largest proportion of the total measured organochlorines (60% in Madeira Island and 85% in Northwest Portugal), followed by DDTs, and lastly, HCB. Considerable differences in the organochlorine profile were identified between samples from Madeira and Northwest Portugal, with common dolphins showing higher PCB loads in Northwest Portugal (53 ± 37 μg g -1 lw) compared to Madeira Island (11 ± 4.8 μg g -1 lw). The high levels of PCBs found in individuals from mainland Portugal - reaching values up to 140 μg g -1 lw - are some of the highest reported for the species worldwide, considerably exceeding toxicity thresholds. This is of particular concern as they may be potentially affecting important physiological processes of the animals. These results highlight the poor habitat quality in one of the studied regions, with potential impacts on ecosystem health, while offering valuable insights into the population structure of a species that remains understudied for effective management and conservation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Environmental safety has become a major concern in recent years due to the global increase in microplastic pollution. These ubiquitous, tiny, and potentially toxic plastic particles enter aquatic environments through weathering of larger plastics and the release of microbeads. Although numerous studies have focused on microplastic pollution in developed regions, information from developing countries remains limited. This study assessed the presence of MPs and associated oxidative stress responses in two commercial fish species, Clarias gariepinus (Catfish) and Oreochromis niloticus (Nile Tilapia), from Kubanni reservoir, Zaria, Nigeria, over six months spanning both the dry and rainy seasons. Fibers were identified as the most abundant MP particles, followed by fragments, films, and beads, in the order of fibers > fragments > films > beads. The highest fiber concentrations were recorded in the gills, with Clarias garipinus showing 11.5 MP items/individual and Oreochromis niloticus showing 22.5 MP items/individual. Black microplastics were predominant, and the most common ingested MP ranged from 1.0 to 2.0 mm. The primary polymers identified were polypropylene and polyethylene terephthalate. Evidence of oxidative stress and cellular damage was observed in the gills, liver, and dorsal muscles of both fish species, which correlated with MPs ingestion. According to recommendations from the European Food Safety Authority regarding fish consumption by children and adults, individuals consuming Clarias gariepinus and Oreochromis niloticus from the Kubanni reservoir may be exposed to between 70 and 700 MP items/organ. The risk associated with consuming MPs found in fish gills and guts was notably higher, posing significant concerns for human health. This study provides insights into microplastic contamination in commercially important fish from the Kubanni Reservoir and highlights the environmental and public health risks associated with consuming contaminated fish from this ecosystem., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The atmosphere is an important transport medium for polymeric anthropogenic particles such as microplastics (MPs). The analysis of particles deposited on the snowpack enables monitoring the abundance and transport of MPs and semi-synthetic fibers. In the current study, the abundance of MPs and man-made textile fibers in deposited snow in Western Siberia, Russia, was investigated in a large area ranging from the Altai Mountains (52°01″N) to the Arctic Circle (66°30″N). Rayon fibers accounted for 44% of all detected particles, while the remaining 56% were MPs made of PET, PA, PC, PP and other plastics. The highest number of MPs and fibers per unit area was 2817 ± 915 items m -2 with an estimated daily deposition rate of 25.8 items m -2 d -1 . The maximum calculated mass particle load was 4444 ± 1530 mg m -2 or 34.9 ± 12 mg L -1 of melted snow. Particle concentrations in snow were generally higher in the southern parts of Western Siberia but did not significantly correlate with population density. The Lagrangian dispersion model FLEXPART was used to estimate the geographical patterns of potential sources of the fibers detected in the snow in Western Siberia. Our analysis shows that particles can reach the sampling sites via both short-range and long-range atmospheric transport, including the possibility of cross-border transport for the smaller particle sizes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The macroplastics (MaPs) and microplastics (MiPs) polluting agricultural soils raise great concerns. Unfortunately, scientists know little about the occurrence of MaPs/MiPs in soil among different farming systems. In this study, we analyzed MaPs/MiPs in soils (0-30 cm) collected from six different farming systems (wheat-maize rotations, cotton, vegetables, permanent orchards, greenhouses with and without mulching) in Quzhou county, the North China Plain, by using fluorescence microscope and micro-Fourier transform infrared spectroscopy. The results showed that the abundance of MaPs and MiPs ranged from 0.2 to 46.8 kg ha -1 , and 4.1 × 10 3 -3.7 × 10 4 items kg -1 , respectively. The prominent colors of the MaPs were white and black. The predominant shape, size and chemical composition of soil MiPs were fragments (45-62%), <1 mm (98-99%), and polyethylene (38-43%), respectively. MaPs were mainly detected in the 0-10 cm soil layer. MiP abundance in the 0-10 cm soil layer was significantly higher than that in the 20-30 cm soil layers among different farming systems, except for the fields with wheat-maize rotations and permanent orchards (p < 0.05). Overall, cotton fields showed the highest MaP and MiP abundance, followed by vegetable fields and orchards. Redundancy analysis revealed that tillage practices and plastic film management greatly influence the size distribution of MiPs. A strong negative correlation between large-sized plastic fractions (0.2-1 mm) and tillage frequency was tested while the years of application of plastic films and the abundance of plastic residues showed a strong positive correlation with small-sized plastic fractions (<0.2 mm). Our findings conclude that agricultural mulch films are an important source of MaPs and MiPs in agricultural soil and distributions are strongly influenced by agricultural management practices and farming systems. Further studies should take farming systems and farming practices into account, thereby exploring the potential mechanisms of plastic fragmentation and granularization in agricultural soil., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Carbonaceous aerosols primarily comprise organic carbon (OC) and black carbon (BC). Thermal-optical analysis (TOA) is the most commonly used method for separating carbonaceous aerosols into OC and EC (BC is referred to as elemental carbon EC, in this method). Advances in hardware design and algorithms have expanded the capabilities of TOA beyond just distinguishing OC and EC. However, a comprehensive understanding of the enhanced functionality of TOA is still lacking. This study provides the first comprehensive review of the TOA technique, highlighting expanded capabilities to measure brown carbon (BrC), mass-absorption efficiency, absorption enhancement, source contributions, and refined OC/EC split points. This review discusses the principles, advantages, and limitations of these advancements. Furthermore, the TOA system anticipates further advancements through integration with other instruments, establishing correlations between EC values obtained from different TOA instruments/protocols, correlating between BrC measurements from TOA and non-TOA methods, and developing an algorithm to quantify BrC from progressive absorption Ångström exponent (AAE) values. This review enhances the understanding of the TOA system and its implication for air quality and atmospheric radiation research., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An in-depth investigation of the maximum environmental load is crucial for soil security and pollution prevention. This research focused on soil environmental carrying capacity (SECC) for different risk receptors in a Chinese industrial city. By determining risk threshold for various land use types, we integrated mass balance and iterative models to capture dynamic net input fluxes with spatial heterogeneity. This enabled quantitative characterization of Benzo(a)pyrene (BaP) SECC through top-down and bottom-up approaches (corresponding to duration (D) and rate of regional emission, respectively). The thresholds were in the order of agricultural land < residential land < forest < industrial land < park. The top-down analysis showed D increased ∼1.5x with a 5% input flux decline until 2031. The bottom-up analysis suggested industrial emissions decreased by approximately 10% as the pollution control period was extended from 20 to 50 years. Both methods showed that at maximum background values (C 0 ), D was ∼4x and the industrial emission rate was ∼10% higher than at minimum C 0 . SECC values near industrial areas significantly decreased, even reaching negative values, signifying complete carrying capacity loss. This study provided an approach to the dynamics of SECC under diverse scenarios, aiding informed decision-making for sustainable land management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This is the first large bio-surveillance study examining the contents and geographic variation of metals of public health concern-arsenic (As), lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), and cobalt (Co)-in honey samples collected across the United States. Metal concentrations were measured using ICP-MS, and the spatial distribution pattern of these contaminants was evaluated using statistical and GIS tools. The mean (highest) values (in μg/kg) were 3.8 (170) for As, 8.0 (451) for Pb, and 0.75 (8.1) for Cd. These values, as well as the mean (highest) concentrations of 29.5 (516) for Ni, 14.3 (166) for Co, and 19.6 (11) for Cr, were markedly lower than global averages reported in other countries. The study identified distinct geographic patterns of honey contamination; particularly high As levels were found in northwestern states, while high Co was measured in the southeast. Health risk calculations based on the hazard quotient (HQ) and hazard index (HI) were below 1 for a daily tablespoon (21g) of honey consumption, indicating no adverse health concerns for children and adults, and all samples fell below the 1.0 × 10 -6 threshold for carcinogenic risk from As. The variation in metal concentrations found in samples from different states may reflect the influence of air, water, or soil pollution, as well as differential accumulation across plant species, and the distinct geographic clustering of As and Co warrants further investigation to determine the sources of these metals and to assess public health risks, particularly for As, a well-known carcinogen. In sum, this initial study provides baseline values of metal concentrations in honey that can be useful for monitoring future pollution trends, identifying target areas where reductions of emissions or remediation efforts are most critical, and facilitating discovery in environmental exposures (the exposome) and health research, including on cancer and cardiovascular diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The extraction and characterization of atmospheric ultrafine particles (UFPs) is critical to understanding environmental health and climate dynamics. This study uses an aqueous extraction method to characterize the size distribution, shape, and composition of atmospheric UFPs. We propose a combined use of techniques rarely implemented in air quality analysis, such as atomic force microscopy (AFM), with more conventional methods, such as Transmission Electron microscopy (TEM) and Dynamic Light Scattering (DLS). DLS results indicate a hydrodynamic diameter range from 117 to 1069 nm and a polydispersity index of 0.3-0.79. The high polydispersity reflects the complexity of UFPs agglomeration processes. AFM identified NPs ranging from 10 to 25 nm; topographic images show soot and crystalline structures. High-resolution TEM analysis measured the interplanar distances of crystalline UFPs, showing the presence of calcium carbonates. TEM-EDS identified soot and crystalline particles with variable composition, from Si-enriched NPs to Ca-F-Cl-Na-Si, carbonates, chlorides, and Zn-Ti-enriched nanosilica. These findings provide valuable insights into the physicochemical properties of atmospheric dust, contributing to our knowledge and the potential implications for human health and the environment., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Diana Meza-Figueroa reports financial support was provided by National Council for Science and Technology Mexico- CONAHCYT Grant 317557. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ammonia emissions from gasoline vehicles have been confirmed an essential precursor of urban secondary aerosols. To more comprehensively understand the formation mechanisms and better control vehicle-related ammonia, this paper measured the on-road ammonia emissions from six conventional and four hybrid vehicles using a state-of-the-art Quantum Cascade Laser analyzer on urban, rural, and highway routes. The test vehicles emitted 0.01-4.27 mg/km of ammonia emissions, with a fleet average of 1.04 mg/km. Compared to the previous laboratory tests, the results of this study were low because of the high emission standards of the vehicles and the near-zero emissions during rural driving. Most test vehicles showed high ammonia emissions during engine warm-up, while some vehicles also had ammonia peaks during dynamic highway driving. On average, hybrid vehicles emitted 60.7% less ammonia emissions than the conventional candidates. It is confirmed that ammonia was formed when incomplete oxidation products presented on a warm catalyst. Engine warm-up, dynamic highway driving, particulate filter regeneration, and hybrid engine re-starting could be important sources. It is hypothesized that the ammonia formed on the upstream catalyst could be consumed by the downstream catalyst at moderate catalyst temperature, resulting in the near-zero ammonia emissions during rural driving., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Groundwater is a vital natural resource that has been extensively used but, unfortunately, polluted by human activities, posing a potential threat to human health. Groundwater in the Yinchuan Region is contaminated with NO 3 - , which is harmful to the local population. This study utilized the eXtreme Gradient Boosting (XGBoost) model with the SHapley Additive exPlanations (SHAP) method to identify the key factors influencing groundwater nitrate pollution in the Yinchuan Region. The SHAP feature dependence plots revealed the intricate relationship between NO 3 - levels and TDS, Mn 2+ , TFe, and pH in complex groundwater systems. The results indicate that the high levels of groundwater NO 3 - are primarily caused by the combined effect of irrigation water from the Yellow River, shallow groundwater depth, unfavorable drainage, water recharge, overuse of fertilizers, and geological factors such as weathering nitrogen-bearing rocks. Hydrochemical parameters such as Mn 2+ , Fe 2+ , and pH create a strong reducing groundwater environment, resulting in lower NO 3 - concentrations in this region. Well depth and soil organic carbon at a depth of 80-100 cm have a negative impact on NO 3 - concentrations; conversely, sand in soil depths 0-20 cm and 100-150 cm and climatic factors such as precipitation have a weak but positive effect on the level of NO 3 - in groundwater in the region. The recommendation is to quickly and extensively implement a farming water-conservancy transformation project, reducing water-intensive crops, promoting groundwater use for irrigation in areas where soil salinization is a concern are proposed. This research could provide local agencies with a scientific foundation for sustainable management of farming and groundwater in the Yinchuan Region, ultimately benefiting the entire Yinchuan Plain., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Data on airborne microorganisms, particularly in Southeast Asia, are more limited compared to chemical data. This study is the first to examine the community and diversity of microorganisms on PM 2.5 in an urban area of Northern Thailand during both smoke haze and non-smoke haze periods of 2020. This study evaluated the composition of airborne bacteria and fungi and analyzed their association with the chemical composition of PM 2.5 and meteorological variables. Significantly higher concentrations of PM 2.5 and more chemical compounds were observed during the smoke haze period compared to the non-smoke haze period. Increased PM 2.5 concentrations significantly altered both bacterial and fungal communities. The diversity and richness of airborne bacteria increased, whereas those of fungi decreased. The level of PM 2.5 concentration (the carrier), the chemical composition of PM 2.5 (the resources for survival), and the local meteorological conditions (relative humidity (RH)) were associated with the differences in bacterial and fungal populations. In addition, air originating from the west of the receptor site, influenced by both terrestrial and marine air mass routes, contributed to higher bacterial diversity and richness during the smoke haze period. In contrast, fungal diversity and richness were greater when the air came from the southwest, following a marine route. However, the primary health concern is pathogens, which were present in both periods (such as Clostridium, Aspergillus, and Cladosporium) and were especially abundant during smoke haze periods. This study highlights those airborne microorganisms, along with the particles and their chemical composition, are important components that can impact health, including that of humans, animals, and the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) pollution is ubiquitous, causing serious ecological damage by threatening the growth and health of living organisms. This study investigated the vertical and horizontal distribution of MPs, MPs-heavy metals (MPs-HMs) accumulation, contamination assessment and microbial biodiversity in hyporheic sediments of different land-use types. MPs abundance in shallow sediments (0-30 cm) was significantly higher than that in deep sediments (30-60 cm), with fewer large MPs in the deep sediments. Blue, fiber, and <500 μm were the dominant MPs types, and polystyrene, polylactic acid, and polyvinyl chloride were the dominant polymers in the Beiluo River Basin. The average concentrations of HMs detected in MPs were all much higher than the same metals in the sediments. The pollution loading index of MPs was higher in areas with a greater proportion of anthropogenic land use, and MP-HM were present to varying degrees in the vertical distribution (P N  > 1). Critically, bacterial diversity of anthropogenic land use was smaller than that of natural land use. High MP-HM concentrations reduced the abundance of cyanobacteria, nitrospirota, acidobacteriota, and planctomycetota, whereas desulfobacterota, chloroflexi, myxococcota, actinobacteriota, and proteobacteria have developed tolerance to MP-HM. Overall, our findings contribute to the understanding of the relationship between different land-use types and the spatial distribution of MPs and MP-HM, which is critical to manage and mitigate the hyporheic zone pollution., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Jinxi Song reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) pollution has emerged as a global concern. To mitigate the potential threats by MPs, particularly to coastal regions, it is crucial to comprehend the environmental behavior of MPs and their affiliated chemicals. In the present study, we collected floating MPs using a Manta net (0.33 mm mesh size) in a one-year sampling event in 2022 from the eight major estuaries in the Pearl River Delta, China, and also from five coastal sites in August and December in the same year. Nineteen linear alkylbenzenes (∑ 19 LAB) and 16 polycyclic aromatic hydrocarbons (∑ 16 PAH) affiliated with MPs were measured. The mean concentrations of MPs-affiliated ∑ 19 LAB and ∑ 16 PAH were 6710 (range: 3400-12300) and 5310 (range: 817-19,600) ng g -1 , respectively, at the estuarine sites, and were 4920 (range: 2400-7600) and 2610 (range: 911-7890) ng g -1 , respectively, at the coastal sites. Significant correlations were found between logarithmic MPs-water partition coefficients (log K pw ) and logarithmic suspended particulate matter-water partition coefficients (log K d ) values for LABs and PAHs, indicating analogous partitioning dynamics for MPs and suspended particulate matter with water. The annual riverine outflows were 1170 and 414 g for ∑ 19 LAB and ∑ 16 PAH, respectively. Although the riverine outflows of LABs and PAHs carried by MPs remain negligible compared to those by suspended particulate matter, an upward trend was identified between 2018 and 2022. Notably, the riverine input of LABs and PAHs carried by suspended particulate matter to the coastal ocean decreased from 2005/2006 to 2022, due to a combination of improved technological processes and energy structures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The emission factors and characteristics of pollutants from river vessels are critical for understanding the environmental impact of ship emissions, particularly in inland waterways. However, research gaps remain regarding emissions of volatile organic compounds (VOCs) and intermediate-volatility organic compounds (IVOCs) from river vessels. In this study, we collected and analyzed organic vapor emissions, including non-methane hydrocarbon (NMHCs), oxygenated volatile organic compounds (OVOCs) and IVOCs, from three river vessels under different operating conditions. The results show that the average emission factors of NMHCs, and IVOCs from river vessels are significantly higher than those from ocean-going vessels. Inland waterways' proximity to residential areas increases the risk of pollutant transport to urban environments, heightening the importance of managing river vessel emissions. Notably, older auxiliary engines displayed higher organic vapor emissions compared to main engines, underscoring the need for better control measures for aging engines. By analyzing the emission characteristics of organic vapors from river vessels, it was found that, unlike other pollution sources where C12 n-alkanes are the major contributors of IVOCs, the contributions of C12-C15 n-alkanes in river vessel exhaust are similar, with C14 n-alkane having the highest contribution. OVOCs constituted more than 50% to ozone formation potentials of organic vapors, while IVOCs were responsible for over 90% of the secondary organic aerosol (SOA) formation. Given these findings, targeted efforts to reduce OVOCs and IVOCs emissions from river vessels should prioritized to mitigate their environmental impact., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Obtaining the high-resolution distribution characteristics of urban air pollutants is crucial for effective pollution control and public health. In order to fulfill it, mobile monitoring offers a novel and practical approach compared to traditional fixed monitoring methods. However, the sparsity of mobile monitoring data still makes it a challenge to recover the high-resolution pollutant concentration across an entire area. To tackle the sparsity issue and fulfill a prediction of the spatiotemporal distribution of PM 2.5 , a high-resolution urban PM 2.5 prediction method was proposed based on mobile monitoring data in this study. This method enables prediction with a spatial resolution of 500m × 500m and a temporal resolution of 1 h. First, a Light Gradient Boosting Machine (LightGBM) was trained using mobile monitoring of PM 2.5 concentration and exogenous features to obtain complete spatiotemporal PM 2.5 concentration. Second, a model consisting of Convolutional Neural Network and Transformer (CNN-Transformer) with a customised loss function was established to predict high-resolution PM 2.5 concentration based on complete spatiotemporal data. The method was validated using real-world data collected from Cangzhou, China. The numerical results from cross-validation showed an R 2 of 0.925 for imputation and 0.887 for prediction, demonstrating this method is suitable for high-resolution spatiotemporal prediction of PM 2.5 concentration based on mobile monitoring data., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Accurate predictions of atmospheric particulate matter can be applied in providing services for air pollution prevention and control. However, the forecasting accuracy of traditional air quality models is limited owing to model uncertainties. In this study, we developed a deep learning model, named multiscale depth-separable UNet (MDS-UNet), to improve PM 2.5 and PM 10 concentration forecasts from WRF&#95;Chem over China. Results showed that MDS-UNet was able to capture the complex nonlinear errors between model predictions and observations, which was helpful in correcting the biases and spatiotemporal distribution patterns of PM 2.5 and PM 10 concentrations predicted by WRF&#95;Chem. MDS-UNet made a better performance in the improvement of both PM 2.5 and PM 10 prediction accuracy than UNet and CNN during the 0-24 forecasts. Using MDS-UNet, the reductions in the root-mean-square error (RMSE) of the regionally averaged PM 2.5 and PM 10 concentration forecasts were 35.08% and 17.74%, respectively. During the 0-24-h forecast period, MDS-UNet performed well in terms of PM 2.5 and PM 10 over six key urban agglomerations in China. Taking a pollution process as a case study, results demonstrated that, compared with WRF&#95;Chem, MDS-UNet was able to make the best improvement in YRD, the Sichuan Basin, and central China, with reductions in the RMSE of the PM 2.5 forecasts of 55.22%, 55.53%, and 52.17%, respectively; and for PM 10 forecasts these reductions were 44.90%, 40.97%, and 46.79%, respectively. Through this analysis, it was apparent that MDS-UNet demonstrated a better effect in terms of improving both PM 2.5 and PM 10 predictions in these key urban agglomerations during an important pollution process., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Hongnian Liu reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)