Search Results (2,133)

Reducing carbon emissions while improving air quality is a central challenge for rapidly urbanizing regions. Focusing on 31 prefecture-level cities in the Middle Reaches of the Yangtze River Urban Agglomeration, this study examines carbon–pollution synergy (CPS), spatial dynamics, and the driving factors of CO₂ and representative air pollutants from 2013 to 2023. Spatial autocorrelation analysis, a revised four-factor Logarithmic Mean Divisia Index (LMDI) decomposition, and a factor-based CPS assessment were used to identify spatial clustering, compare driver heterogeneity, and evaluate coordination between CO₂ and primary pollutants. To improve methodological consistency, the LMDI decomposition and CPS assessment focus on the primary pollutants SO₂, CO, and NO₂, whereas PM_2.5 and O₃ are retained in the spatial analysis and discussion because they are strongly affected by secondary formation, atmospheric transport, and meteorological conditions. The results show that CO₂ and the selected pollutants exhibit significant but pollutant-specific spatial clustering. High CO₂ values remain concentrated in the core cities of Wuhan, Changsha, and Nanchang, PM_2.5 shows a persistent north–south gradient, and SO₂ hotspots shift from traditional industrial cores toward peripheral areas receiving industrial relocation. The revised LMDI results show that economic development is the most stable positive driver of CO₂ and the primary pollutants, whereas the energy-consumption factor generally suppresses emissions. The recalculated population-scale factor fluctuates around 1, indicating a comparatively limited and stage-dependent contribution once the other factors are controlled for. CPS analysis further indicates that coordinated reduction is most robust under the energy-consumption factor and, for conventional combustion-related pollutants, also under the energy-structure factor. Overall, the region has a clear basis for CPS governance, but effective implementation requires pollutant-specific and region-specific control strategies rather than a uniform co-mitigation pathway. Full article

Remote alpine lakes on the Xizang Plateau are important archives for tracing the long-range atmospheric transport (LRAT) of persistent organic pollutants, yet historical records of polybrominated diphenyl ethers (PBDEs) from this region remain scarce. The main objective of this study was to reconstruct the historical record of PBDEs in Yamzho Yumco sediments and to evaluate whether this record reflects source evolution, atmospheric transport, deposition, and post-emission environmental fractionation in a remote alpine receptor system. To achieve this objective, 17 PBDE congeners were determined in a ²¹⁰Pb- and ¹³⁷Cs-dated sediment core spanning 1930–2023. Σ₁₇PBDE concentrations ranged from 5.80 to 263.13 pg/g dw, and depositional fluxes ranged from 2.67 to 121.04 pg/cm²/yr, both showing a marked increase after the 1970s and remaining elevated after 2000. Lower-brominated congeners, especially BDE-47, dominated the core, whereas nona- and deca-BDEs appeared mainly in recent sediments, indicating progressive source evolution in recent decades. Tri- to penta-BDEs remained the dominant homologue fraction throughout the record, while elevated post-2000 BDE-47/BDE-99 ratios point to congener-selective environmental fractionation during atmospheric transport and deposition. Together, these results suggest that Yamzho Yumco sediments preserve not only the history of regional PBDE input, but also the coupled imprint of source evolution, transport-related fractionation, and delayed environmental response in a remote high-altitude receptor system. This study highlights the value of Xizang Plateau Lake sediments for process-based interpretation of POP fate in mountain environments. Full article

Micro- and nanoplastics (MPs/NPs) are increasingly recognized as persistent contaminants in agricultural systems, where repeated inputs from mulch films, biosolids, composts, irrigation water, and atmospheric deposition create sustained exposure pathways for crops. Although various studies report effects on crop growth and physiology, mechanistic interpretation remains limited because outcomes vary widely across experiments and are often discussed without appropriate attention to exposure context, particle properties, and evidentiary strength. This review advances an agroecosystem-centered, evidence-aware framework for interpreting how MPs/NPs influence crops from environmental entry to plant phenotype. We argue that crop responses cannot be inferred from polymer identity alone, but must be interpreted through the interacting effects of particle size, morphology, surface chemistry, weathering state, aggregation behavior, co-contaminant associations, and exposure matrix. Within this framework, crop responses are organized along a mechanistic chain linking environmental entry and plant contact, interface behavior at root and leaf surfaces, conditional barrier crossing and transport, ROS-centered stress signaling with hormonal and ionic regulation, and downstream effects on germination, root function, photosynthesis, biomass, productivity, and quality-related traits. Particular emphasis is placed on distinguishing surface association, supported internalization, and supported systemic translocation, because these categories carry distinct implications for edible-tissue occurrence, crop quality, and food-system relevance. Current evidence suggests that the soil–plant–food pathway is plausible and increasingly supported, but its interpretation remains constrained by uneven analytical rigor and limited field realism. Future progress will require realistic agricultural exposure designs, stronger polymer-specific confirmation, and closer integration of mechanistic evidence with agronomic and food-system endpoints. Full article

Soils are increasingly affected by microplastic (MP) contamination, mainly coming from industrial activities, agricultural practices, atmospheric or waterborne transport, and improper waste disposal. Despite the increasing attention to the fate of MPs in soil over the last few years, research in this area is still limited compared to aquatic ecosystems. The introduction of MPs into the soil environment can modify not only the soil properties but also the interactions among soil components, plants, and microorganisms, thus affecting the mobility and availability of other contaminants, such as potentially toxic elements (PTEs). This review critically examines the complex dynamics between MPs and PTEs in the soil ecosystem, with a focus on the conditions under which MPs can act as a source or a sink of PTEs. Indeed, on the one hand, MPs can adsorb or complex PTEs on their surfaces (similarly to natural soil colloids), thus reducing their mobility and availability; on the other hand, they can release/mobilize PTEs after MP degradation or act as micro-/nano-vectors of PTEs. Understanding such mechanisms is relevant when evaluating the environmental risks associated with the co-presence of MPs and PTEs in soil, a situation likely to occur in most contaminated sites and in many agricultural soils. Full article

Dioxins are highly persistent organic pollutants that exist in soil. Their hydrophobic and lipophilic characteristics facilitate long-term stability, posing high risks to the ecosystem and human health. They can be released by different sources, such as the incineration of waste materials, industrial activities, the production of pesticides, and natural or accidental events like forest fires. Dioxins accumulate in food chains and persist in the environment because dioxins are less volatile as well as chemically stable and can strongly bind to organic matter. The accumulation and persistence of dioxins in aquatic and terrestrial systems make them a significant threat to the environment, even at very low concentrations. This review explains the key sources of dioxin-contaminated soil, including industrial emissions and atmospheric deposition, and assesses the associated risks. The transport, places of contamination, and overall status of dioxins are also highlighted in this study. The review also examines the mechanisms of dioxin toxicity, focusing on their interference with hormonal functions and gene expression, as mediated through the aryl hydrocarbon receptor (AhR). This AhR activation leads to gene responses and causes immunotoxicity, endocrine disruption, and oxidative stress. Furthermore, various remediation strategies like biological, physical, and chemical remediation are discussed here as effective approaches for reducing ecological and health risks and promoting soil sustainability. Full article

In this study, we present a machine-learning approach—a land use random forest (LURF) model—to produce daily PM₁₀ concentration maps at a 1 km resolution across the Campania region for the year 2022. The model combines daily measurements from 13 ARPA Campania monitoring stations with a wide set of spatial and atmospheric information. The predictors include population, land cover, road network, ERA5 meteorological data, satellite aerosol observations from MODIS, output from the CHIMERE chemistry transport model, and a flag identifying days affected by Saharan dust transport. The model is trained and validated using a station-based cross-validation scheme that accounts for spatial correlation between sites. Under this scheme, the LURF reproduces observed concentrations with substantially smaller errors than the raw CHIMERE output (RMSE of 11.0 vs. 23.6 $\mathsf{\mu }$g m⁻³). CHIMERE concentrations and ERA5 meteorology emerge as the most informative predictors, while the dust flag specifically improves the representation of episodic high-PM₁₀ events. The resulting 1-km maps reveal clear urban–rural contrasts. They identify pollution hotspots in the Naples metropolitan area and along major motorways that are not visible in coarser model outputs. Probabilistic exceedance maps further show that meeting the future 2030 EU limit value of 20 $\mathsf{\mu }$g m⁻³ will be challenging across much of the metropolitan area. Overall, the proposed framework provides a low-cost, practical tool for high-resolution PM₁₀ exposure assessment, supporting epidemiological studies, environmental justice analyses, and air quality management in regions with complex terrain and limited monitoring coverage. Full article

This study quantitatively analyzed rust-streak formation under controlled droplet supply and its relationship with the rust-removed surface profile of the substrate. A NaCl aqueous solution was dropped at a constant flow rate onto SPCC steel plates inclined at 70° to observe the temporal development of the rust streak. Surface line profiles before and after the removal of red rust were measured, and profile changes were quantified relative to the initial surface. Rust layer height $h_{\mathrm{rust}}\left(x\right)$ and rust-removed surface profile $z_{\mathrm{r}}^{\ast }\left(x\right)$ were determined, and their distributions and integrated values were compared. The rust width reached approximately 2.5–3.0 mm, comparable to the droplet diameter under the present conditions. Downstream, rust layer height increased with the extension of test duration, whereas the integrated profile of the rust-removed surface remained relatively small. Rust layer height and rust-removed surface profile were not directly related at each observation position L. These results suggest that rust streak formation within the tested parameter window involves not only locally formed rust but also rust carried from upstream by liquid flow, and indicate that visible rust morphology alone cannot adequately represent substrate-side profile changes under these specific conditions. Full article

The Antarctic stratospheric ozone plays a crucial role in the polar climate system and is strongly influenced by energetic particle precipitation. Among these processes, medium-energy electron (MEE) precipitation enhances the production of odd nitrogen (NOx) in the polar mesosphere and stratosphere, thereby driving ozone depletion through catalytic reactions. However, quantifying its atmospheric impact remains challenging, largely because the spatial and temporal variability of MEE is poorly constrained, and most current global chemistry–climate models lack a realistic MEE forcing. This study employs the Whole Atmosphere Community Climate Model coupled with Sodankylä Ion Chemistry (WACCM–SIC) to investigate the influence of MEE precipitation during 2013–2014, when moderate geomagnetic storms were more frequent in the winter of 2013. A control simulation (Case1) and two sensitivity experiments (Case 2 and Case 3) were conducted to isolate MEE-driven effects. Model-simulated NO_x (NO + NO₂) and ozone concentrations agree well with satellite observations, indicating that WACCM–SIC captures the key photochemical and dynamical processes. The results further suggest that the direct impact of MEE precipitation on the middle and lower atmosphere during winter is relatively weak. Nevertheless, MEE-generated NO_x can be efficiently transported downward within the polar vortex, reaching altitudes below 15 km. In these regions, MEE-related NO_x enhancement can reach up to 5%, with values during the winter of 2013 approximately twice those in 2014. Sensitivity experiments further reveal that enhanced NO_x leads to pronounced ozone depletion in the lower stratosphere, with ozone losses reaching up to 25%. A clear negative relationship between NO_x and ozone is therefore evident, highlighting the importance of accurately representing MEE precipitation in chemistry–climate models. Full article

The anthropogenic transformation of the steppe zone in the southern East European Plain has led to the destruction and catastrophic fragmentation of natural ecosystems. Due to the presence of highly fertile lands and the deposits of the Donetsk coal basin, up to 90% of the territory is occupied by agricultural and industrial activities, urban agglomerations, other settlements, and extensive transportation networks. The predominant use of introduced species in artificial plantings (within the city limits, the ratio of species to quantity is 7:3) leads to the widespread spread of alien species, further isolation of natural habitats, and their subsequent degradation. The problem of preserving natural ecosystems and restoring a stable balance in their functioning can be solved through the widespread introduction of native species into all types of plantings capable of serving as ecological corridors. In this regard, we analyzed the key characteristics of native tree and shrub species that determine their functional value. The results indicate that of the 85 native plant species, only two cannot be used because they carry pests and diseases dangerous to agricultural crops. The remaining 83 species are suitable for various planting types, based on a set of individual characteristics, and 29 of these are universal for all planting types. Outside urban ecosystems, these 83 native species can completely replace introduced species. Within urban ecosystems, the need for their combination remains. Despite a number of advantages identified in native species in conditions of anthropogenic pollution (relatively high viability, long lifespan, good resistance to mechanical stress), native species lack a number of categories of traits necessary for the more effective functioning of urban green infrastructure. Among them, there is an insufficient number of tall species (>25 m) and conifers, which are more effective in purifying and improving the health of the atmosphere, as well as beautifully flowering and generally highly decorative species necessary for recreational areas and other territories that, among other things, perform esthetic functions. Full article

The high emissions of carbon dioxide (CO₂) into the atmosphere have driven the development of carbon capture, transport, and storage (CCTS) technologies. These focus on capturing CO₂ from industrial exhaust gases and transporting it through existing pipeline networks. Although various capture techniques are available, they may introduce impurities such as O₂, N₂, Ar, H₂O, NH₃, and others into the CO₂ stream. These contaminants can significantly alter the thermophysical behaviour of the fluid, making the phase behaviour predictions, reliable for pure CO₂, much more complex. Pressure and temperature variations along pipelines can induce unexpected phase transitions, affecting fluid composition and potentially triggering corrosion. This review examines the formation of condensates within pipelines and their role in initiating corrosion phenomena, with a focus on top of the line corrosion (TLC) and conventional CO₂-induced corrosion (sweet corrosion). The main literature findings highlight how phase changes and altered fluid composition due to corrosion processes can significantly intensify degradation mechanisms during CO₂ transport. Full article

During wet deposition, particulate matter and gaseous species in the atmosphere are ultimately transported to the Earth’s surface via precipitation and subsequently incorporated into terrestrial ecosystems. Therefore, investigating the fluxes, chemical compositions, and source apportionment of regional wet deposition is of great scientific importance. An analysis of the concentrations, deposition fluxes, spatiotemporal variations, and source apportionment of water-soluble ions in wet deposition can further enhance our understanding of the water-soluble ion characteristics, atmospheric pollution profiles, and potential ecosystem impacts of wet deposition in the Yangtze River Delta and Pearl River Delta regions. Coastal cities in China are most developed regions, and also areas suffering from severe air pollution. This study investigates the chemical characteristics, sources and wet deposition fluxes of water-soluble inorganic ions in precipitation in two typical coastal urban agglomerations of China: Ningbo in the Yangtze River Delta and Guangzhou in the Pearl River Delta. Precipitation samples were collected and analyzed to determine the concentrations of major ions. The results revealed distinct ionic compositions between the two regions. In Ningbo, NO₃⁻ and SO₄²⁻ were the predominant ions accounting for 16.98% to 23.22% of the total, reflecting the influence of anthropogenic emissions from fossil fuel combustion and mobile sources with the NO₃⁻/SO₄²⁻ ratio of 0.90 and 0.70. In Guangzhou, precipitation was characterized by high contributions of SO₄²⁻, NO₃⁻, NH₄⁺, and Ca²⁺, accounting for 17.22% to 23.29% of the total, indicating a mixed influence of industrial emissions, agricultural activities, and construction dust with the NO₃⁻/SO₄²⁻ ratio of 0.92 and 0.87. A clear inverse relationship between rainfall amount and ion concentration was observed at all sites (p < 0.05), demonstrating a significant dilution effect. Seasonality played a crucial role in deposition fluxes. In Ningbo, fluxes peaked during summer from 4667 to 5156 mg·m⁻², while in Guangzhou, distinct dry and rainy season patterns influenced the scavenging efficiency of different ion species. Urban sites exhibited enhanced scavenging of crustal and anthropogenic ions (e.g., Ca²⁺, NH₄⁺) during the rainy season, whereas the coastal site showed elevated fluxes of marine-derived ions (Na⁺, Cl⁻, Mg²⁺, SO₄²⁻) during the same period. The observed trends in ion fluxes suggest a gradual improvement in regional air quality over the study period. These findings elucidate the complex interactions between anthropogenic activities, natural sources, and meteorological factors in shaping the wet deposition chemistry in coastal urban environments, providing essential data for developing regional deposition models and assessing the ecological impacts of atmospheric pollution. Full article

Helium-rich unconventional natural gas resources have attracted increasing attention from both academia and industry. A pronounced local enrichment of helium has recently been identified in coal-derived unconventional natural gas in the Sanjiaobei block on the eastern margin of the Ordos Basin. To clarify the main controls on helium enrichment in unconventional natural gas in this area and to guide the exploration of helium-rich resources, this study systematically examines the source of helium, its transport carrier, multiphase fractionation processes, and enrichment and accumulation pattern in natural gas. The analysis is based on conventional gas composition, helium volumetric content, carbon isotopes, and noble gas isotopes (He, Ne, and Ar) measured from wellhead gas samples collected from 11 production wells in the block, together with the regional deep structural evolution and hydrogeological conditions. The results show that: (1) the helium volumetric content of natural gas in the study area ranges from 0.0175% to 0.214%, with an average of 0.108%, and most wells fall within the high-helium grade category; (2) the helium isotope ratios ³He/⁴He (R/Ra) of the samples range from 0.0148 to 0.0824, indicating a typical crustal helium source; the good positive correlation between helium and nitrogen volumetric contents suggests that the two components share a highly consistent source affinity or common migration and accumulation behavior during fluid evolution; and the extremely high He/Ne ratios, on the order of 10⁴, together with excess Ar isotopes, indicate that the gases experienced little dilution by shallow atmospheric water or modern atmospheric fluids during migration and accumulation. The formation of helium-rich unconventional gas reservoirs on the eastern margin of the Ordos Basin is interpreted to be characterized by basement-derived helium supply, activation by tectonothermal events, groundwater transport, efficient fault-controlled migration, reservoir capture along migration pathways, and sealing by stagnant groundwater and lithologic barriers. On this basis, a helium enrichment model is established. This model depicts the geochemical evolution pathway of trace noble gases in a natural gas system and may provide a useful reference for helium resource evaluation in analogous areas. Full article

We examined the effect of the coronavirus disease 2019 (COVID-19) pandemic on air quality in the Kanto region of Japan using multiple satellites and ground-based observations. The vertical column density (VCD) of nitrogen dioxide (NO₂) derived from the Ozone Monitoring Instrument (OMI) and the Tropospheric Monitoring Instrument (TROPOMI) showed decreases of 38% and 27%, on average, respectively, in March of 2020, compared with the same month in 2015–2019, for OMI and in 2019 for TROPOMI. Surface NO₂ concentrations measured by the Atmospheric Environmental Regional Observation System (AEROS) also declined by up to 22% relative to the 2015–2019 mean, which is consistent with previously reported reductions. To investigate interactions between ozone (O₃) and NO_x, we calculated the ratio of non-methane hydrocarbon (NMHC) and NO_x and potential ozone (PO) surface concentrations from the AEROS data. The results indicated that the ozone formation regime in the Kanto region remained within the NMHC-limited domain during the COVID-19 period and was unchanged from the previous five years. Nevertheless, the baseline O₃ concentration decreased by 2.5–8.5 ppbv, depending on site (urban vs. suburban) and year (2020 vs. 2021). Diurnal variations in PO concentrations (defined as O₃ + NO₂-0.1NO_x), which is the net O₃ concentration produced by photochemical reactions and/or transport excluding the NO titration effect, showed significant reductions of 6.3 ppbv in 2020 and 3.2 ppbv in 2021, suggesting that lower PO levels were mainly attributed to the reductions in baseline O₃ concentrations in 2020. These findings highlight how pandemic-related emission reductions affected chemical processes and dynamics related to both NO_x and O₃ in a major Japanese metropolitan region. Full article

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous combustion-derived contaminants that represent a significant cross-cutting threat to human, animal, and environmental health. Viewed through an explicit One Health lens, this review shows how the shared combustion sources, evolutionarily conserved toxicological mechanisms, and food-web linkages connecting environmental contamination to wildlife and human exposure justify an integrated, cross-domain approach to PAH risk assessment and management. PAHs are generated predominantly through incomplete combustion of organic materials and are globally distributed through atmospheric transport, aquatic runoff, and food-web transfer, persisting in soils and sediments for decades. The present review synthesizes current knowledge on PAHs through an explicit One Health lens, examining shared sources, environmental fate, and convergent health effects across species and health domains, while also highlighting the need to move beyond the classical US EPA priority PAHs to include high-molecular-weight PAHs (>302 Da), alkylated homologues, and transformation products such as oxy- and nitro-PAHs. Common pathways such as dietary intake of grilled and smoked foods, inhalation of contaminated air, and occupational exposure create parallel toxicological burdens in both human and wildlife populations, particularly through genotoxic mechanisms mediated by aryl hydrocarbon receptor (AhR) activation and CYP1A1/CYP1B1-catalyzed bioactivation to reactive diol epoxides. The resulting DNA adduct formation links environmental PAH exposure to carcinogenicity, reproductive toxicity, immunosuppression, and developmental impairment across vertebrate species with remarkable mechanistic consistency. Wildlife, especially fish, marine mammals, and seabirds, serve as critical sentinels for environmental PAH contamination, while simultaneously facing direct health impacts on immune function, reproduction, and population viability. Vulnerable human populations, including children, subsistence communities, occupational workers, and residents near combustion-intensive industries, bear disproportionate burdens reflecting underlying environmental justice concerns. Integrated intervention strategies encompassing source control, dietary exposure reduction, site remediation, and coordinated biomonitoring are urgently needed. By incorporating emerging PAH classes with distinct persistence, trophic behavior, and toxicological potency, the One Health paradigm provides a more comprehensive conceptual framework for modern environmental surveillance, food safety, and integrated risk assessment, recognizing that the health of terrestrial and aquatic ecosystems is inseparable from that of the animals and humans within them. Full article

Atmospheric nitrogen dioxide (NO₂) is an important component of reactive nitrogen and plays a key role in the atmospheric nitrogen cycle outside major emission regions. However, its variability under remote background conditions remains poorly characterized, as most observational studies focus on urban or continental environments. This study investigates the background variability of in situ NO₂ measurements at a remote North Atlantic island (Azores) over the period 2015–2024 and examines its association with large-scale atmospheric transport regimes. Monthly NO₂ concentrations were classified into background Atlantic conditions and months classified under enhanced transport conditions using an objective PM₁₀ percentile-based criterion. Differences between regimes were assessed using non-parametric statistics. Although median NO₂ concentrations were slightly higher during months classified under enhanced transport conditions, the difference was not statistically significant. Wind speed analysis for the overlapping period 2018–2024 also indicated higher values during these months, but these differences were likewise not statistically significant. These results indicate that, at a monthly resolution, the influence of enhanced transport conditions on NO₂ at this remote marine site is weak and not statistically resolved by the present approach. The findings therefore provide limited statistical support for a transport-driven modulation of NO₂ and instead highlight the difficulty of detecting subtle reactive-nitrogen signals in clean marine environments. These findings contribute to improving the interpretation of reactive nitrogen variability in remote marine settings and highlight the value of island observatories for studying the atmospheric nitrogen cycle. Full article