This study reports a defect-engineered CoS2@MoS2 heterostructured catalyst synthesized via a scalable wet mechanochemical route for efficient activation of peroxymonosulfate (PMS) toward the degradation of organic contaminants in water. Structural characterizations reveal that moderate annealing (400 degrees C) enhances crystallinity and interfacial coupling while promoting the formation of sulfur vacancies, thereby improving interfacial electron transfer and reducing charge-transfer resistance. Sulfur vacancies facilitate PMS adsorption and activation, whereas the synergistic Co2+/Co3+ and Mo4+/Mo6+ redox cycles sustain continuous regeneration of active sites. Mechanistic probes, including XPS, EPR, and electrochemical analyses, indicate that PMS activation predominantly proceeds via sulfur-vacancy-regulated interfacial electron transfer, promoting the generation of SO center dot-4 and other reactive oxygen species responsible for BPA degradation. Under optimized conditions, the CoS2@MoS2-2/PMS system achieves complete bisphenol A (BPA) degradation within 15 min, exhibiting excellent cycling stability and low Co/Mo metal leaching. Continuous-flow membrane reactor experiments further confirm stable pollutant removal under dynamic operating conditions, highlighting its practical application potential. The superior performance is primarily attributed to defect-electron-redox synergistic effects at the CoS2/MoS2 heterointerface, which promote PMS adsorption, interfacial charge redistribution, and sustained regeneration of active sites. Overall, this work elucidates a defect-electron-redox coupled PMS activation mechanism and provides valuable insights into the rational design of stable and regenerable heterostructured catalysts for advanced water treatment applications.

The widespread use of chlorine-based disinfectants drives the transformation of indoor contaminants and the formation of secondary pollutants. However, the occurrence, mechanisms, and products of surface heterogeneous reactions remain poorly understood. Here, based on flow tube experiments, we show that cleaning-emitted reactive chlorine gases (RCGs) (containing ∼350 ppb chloramine) react with surface-sorbed aromatic and aliphatic amines, generating diverse transformation products, including nitrosamines, hydrazines, chlorinated species, and dimers. As an example, dibenzylamine exhibited a heterogeneous reaction rate constant of approximately 7.9 × 10-3 min-1 at 30% relative humidity (RH), corresponding to a half-life of ∼2.1 h, and with nitrosamine and hydrazine yields of 6.2% and 1.0%, respectively. Nontargeted analysis identified an extensive suite of additional products for different amines, generated through ring cleavage, hydroxylation, chlorination, oxidation, and dimerization. Product formation and reaction kinetics depend on RH, chloramine levels, and amine structures. We further confirmed the formation of these products during cleaning events in indoor environments. These transformation products exhibit greater environmental persistence than their parent amines, especially for chlorinated products, posing concerning exposure risks. Our findings demonstrate that heterogeneous reactions of surface-bound organic amines during cleaning form structurally diverse, persistent, and hazardous products─a process potentially applicable to a wide range of indoor contaminants.

Wildfire emissions release large amounts of methoxyphenols, which serve as key precursors of aqueous-phase secondary organic aerosols (SOA). Their transformation is closely coupled with aqueous S(IV) oxidation, jointly driving the formation of sulfate and organosulfates; however, the underlying mechanisms remain poorly understood. Here, we identify a metal-free, UVA-driven mechanism for sulfate radicals (SO4 center dot-) generation at 370 nm, supported by laboratory experiments and quantum chemical calculations. Photolysis of the [SO32-+O-2] complex yields a [SO3 center dot-+O-2(center dot-)] pair; the SO3 center dot- radical subsequently reacts with O-2 to form peroxomonosulfate (SO5 center dot-), which then oxidizes S(IV) to produce SO4 center dot-. These sulfate radicals rapidly oxidize guaiacol, a representative biomass burning phenol, in bulk solution, producing SOA enriched in organosulfates. Microdroplet experiments show similar to 100-fold rate enhancement due to interfacial effects. Box modeling indicates that this aqueous UVA pathway represents a potentially important and previously underappreciated source of sulfate. This work establishes a photochemical link between S(IV) oxidation and SOA formation, with implications for aerosol composition, oxidative capacity, and climate-relevant processes.

Abstract Typhoon peripheral conditions modulate the formation and atmospheric fate of ozone precursors, yet the vertical distribution and the underlying physical‐chemical drivers remain less constrained. Here, we examine the vertical profiles of ozone precursor proxies, including formaldehyde (HCHO), glyoxal (CHOCHO), and nitrogen dioxide (NO 2 ), in the Pearl River Delta (PRD) in China during the 2023–2024 typhoon seasons using ground‐based Multi‐Axis Differential Optical Absorption Spectroscopy. Under peripheral conditions, tropospheric columns of HCHO and CHOCHO increase by 30.8% and 34.4%, respectively, with the most pronounced enhancements occurring within 0.5–1.0 km. GEOS‐Chem budget analysis indicates that such shift upward of vertical peaks is driven by intensified enhanced vertical transport that enhances net production by 14.0%–25.0% at 0.5–1.0 km. In contrast, NO 2 profiles remain stable, due to a rebalance between strengthened upward convection and accelerated chemical loss. Such vertical redistributions shift the ozone sensitivity regime from volatile organic compound‐limited to NO x ‐limited within 0.5–1.0 km. Our findings underscore the necessity of height‐resolved monitoring for refining ozone mitigation strategies in coastal cities.

Liquefied petroleum gas (LPG) and natural gas (NG) stoves emit nitrous acid (HONO) and nitrogen oxides (NO x ), two critical atmospheric pollutants, yet their emission characteristics and impacts are not fully understood. This study characterized HONO and NO x emissions and evaluated the influencing factors for both stove types. LPG combustion consistently demonstrated higher emission factors (EFs) than NG. At a high power, HONO and NO x EFs from LPG reached 110 +/- 7 and 1476 +/- 39 mg kg-1 of fuel, respectively, compared to 56.0 +/- 1.4 and 1032 +/- 34 mg kg-1 of fuel for NG. The emissions increased with the power level and duration but decreased in the presence of cookware, indicating previous simulations without cookware likely overestimated EFs. Moreover, NG combustion exhibited higher NO2/NO emission ratios (similar to 3.3) than LPG (similar to 0.7) across all power settings, attributable to the lower flame temperature of NG. The environmental impact of residential stoves extends beyond indoor air, contributing significantly to outdoors. For instance, HONO emissions from residential stoves (3.1 +/- 0.1 kt year-1) exceed those from gasoline vehicles (0.6 +/- 0.2 kt year-1) in China. These findings highlight the significance of domestic gas stoves in atmospheric chemistry and provide key data for refining the HONO emission inventories.

Nocturnal ozone enhancement (NOE) extends ozone exposure and may exacerbate risks to human health and ecosystem, yet its impacts on fine-particle matter (PM2.5) chemistry remain poorly constrained. We characterized NOE occurrence across four Chinese megacities (Beijing, Shanghai, Guangzhou, and Shenzhen; 2019-2024) and integrated year-long in-field observations in Shenzhen with nontarget ultrahigh-resolution mass spectrometry and statistical analysis to examine NOE events. Here we show that NOE events in a megacity occurred with an average frequency ranging from 9.82 to12.37%. In Shenzhen, NOE events were associated with stronger mixing signatures and elevated nocturnal oxidizing capacity. Secondary aerosol components were enhanced and dominated the PM2.5 response, as indicated by a more than 2-fold increase in the nitrate oxidation ratio, higher organic carbon/elemental carbon(OC/EC) ratio, and elevated particle oxidative potential. Importantly, these oxidizing and aerosol enhancements persisted into the subsequent daytime. At the molecular level, water-soluble organic matter shifted toward highly oxidized, carboxyl-bearing CHO species, and we identified 11 NOE-characteristic compounds dominated by CHO formulas. These results link nocturnal ozone dynamics to particle chemistry and highlight nighttime ozone as a lever for joint control of urban O3 and PM2.5.

A precise understanding of indoor particle dynamics requires moving beyond traditional mass- or number-based metrics, which lack the detailed molecular composition information needed to identify key processes governing organic aerosols (OAs). Here, we developed and applied a novel molecular-level framework based on nontarget, high-resolution mass spectrometry analysis of OA composition from multiple sites. This framework resolves the impacts of transport and partitioning, as demonstrated by characterizing particles simultaneously collected from the living room, kitchen, and outdoors of an apartment. Our analysis revealed that outdoor transport was the primary source of living room OA and that the indoor/outdoor ratios of specific components differ from those of bulk particle mass, implying compound-specific transport behaviors. Furthermore, semivolatile organic compounds were found to partition from indoor surfaces into aerosols, as evidenced by benzalkonium chloride cleaning experiments. These results demonstrate that transport and surface-gas partitioning critically shape OA composition at the molecular level, highlighting the limitations of conventional mass- and number-based approaches in capturing the drivers of compositional change and exposure-relevant indoor OA dynamics. More importantly, our framework provides a transferable approach with broad applicability beyond this specific indoor environment, enabling future investigations of OA evolution across various atmospheric settings.

Boron modification has been validated as an efficient strategy for boosting Fe-based Fenton catalysis. Nevertheless, it remains challenging to synchronously achieve boron doping and heterostructure modulation while steering ROS generation pathways. Herein, a novel B-FeS2 nanocatalyst with dual modification was synthesized via a wet mechanochemical-thermal method. Boron modification constructs a FeS2/boron sheet heterostructure that suppresses oxidation and agglomeration, while introducing electron-donating BB and FeB bonds. The B-FeS2 Fenton system achieves >90% BPA removal across a wide pH range (3-10), exhibits Kobs and mineralization efficiency 1.4 and 1.89 times higher than those of bare FeS2, respectively, and maintains stable performance over five cycles and 12 h continuous operation. Mechanistic studies reveal that B doping upshifts the Fe d-band center, which correlates with an altered H2O2 cleavage pathway characterized by enhanced ·O2- generation alongside sustained ·OH production, suggesting a possible shift in the relative contribution of homolytic versus heterolytic pathways. The generated ·O2- directly degrades BPA and sustains Fe2+/Fe3+ cycling via the Haber-Weiss reaction, a synergy particularly advantageous under alkaline or anoxic conditions. This work demonstrates that B modification serves as an effective electronic modulator for FeS2, providing mechanistic insights into designing iron-based Fenton system with tailored ROS pathways.

The cotton-air partition coefficient (Kca) is a key parameter governing the concentration and human exposure to volatile organic compounds (VOCs) in indoor environments. We experimentally determined Kca for 46 diverse VOCs, including carbonyls, aromatics, amines, amides, alkenes, acids, alcohols, furan, and siloxanes. Results showed that compounds with a lower vapor pressure and higher molecular weight exhibited stronger sorption. Water sorbed in cotton contributed less than half an order of magnitude to Kca for most VOCs, except for some highly water-soluble species. Octanol-air partition coefficients (log Koa) correlate well with log Kca for homologous compounds but demonstrate limited predictive capacity across different VOC classes. The predictions of log Kca using methyl cellulose as a cotton surrogate led to deviations of up to one log unit. We developed a polyparameter linear free energy relationship (pp-LFER) model for log Kca prediction based on the experimental data. The model shows good agreement with experimental data (adjusted R2 = 0.73, root-mean-square error ∼ 0.55 log units), providing a useful tool for chemical distribution and exposure assessment. Field investigations further demonstrated that environmental factors (temperature, humidity, particle deposition, and interfering compounds) can induce 1-2 orders of magnitude variation in Kca values compared to controlled laboratory measurements.

Limited interfacial electron transfer and sluggish metal redox cycling constrain peroxymonosulfate (PMS) activation by iron-based biochar. Here, Co-, Cu-, Ni-, and Zn-doped iron biochars were synthesized via two-step pyrolysis and evaluated for the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). CoFe/BC exhibited the highest activity, removing 92.56% of 2,4-D within 60 min with an observed rate constant of 0.0216 min-1, 6.0-12.7 times those of the other bimetallic catalysts. Spectroscopic characterization and density functional theory calculations showed that Co incorporation increased carbon graphitization, enriched oxygen-vacancy sites, and promoted charge redistribution across the CoFe oxide/carbon interface. These structural and electronic changes strengthened PMS adsorption and facilitated interfacial electron transfer. Selective site masking and postreaction X-ray photoelectron spectroscopy identified surface Co(II) as the primary PMS activation site, whereas the Fe(II)/Fe(III) couple acted mainly as an electron buffer that sustained Co redox cycling. Quenching experiments and electron paramagnetic resonance spectroscopy revealed coupled radical and nonradical oxidation pathways, with singlet oxygen playing the dominant role in 2,4-D degradation. The system retained 85.75% and 76.01% removal in river water and reclaimed water, respectively, although strongly alkaline conditions and increasing concentrations of chloride, bicarbonate, and humic acid inhibited degradation. After five cycles, 2,4-D removal decreased to 45.05% because of metal leaching and surface fouling but recovered to 86.37% after pyrolytic regeneration. In continuous flow, a fixed bed packed with CoFe/BC-loaded hydrogel beads maintained greater than 50% removal after treating 6.46 L of wastewater. These findings demonstrate that engineering oxygen-vacancy-rich metal‑carbon interfaces can enhance PMS activation and support continuous treatment of water contaminated with chlorinated herbicides.

The catalytic conversion of CO2 into value-added fuels via photothermal offers a promising solution to carbon neutrality and sustainable energy production. Nevertheless, the practical application of MOF-based photothermal catalysts is still hindered by limited CO2 activation capability, low density of accessible active sites and inefficient utilization of thermal energy. In this work, a highly amino-functionalized and defect-rich NH2-MIL-125(Ti) catalyst is constructed through one-step hydrothermal synthesis for efficient CO2-to-CO photothermal conversion. Controlled-NH2 incorporation induces framework disorder and defect-rich local environments / OVrelated electron-rich Ti environments, thereby regulating surface electronic structure and adsorption characteristics, facilitating CO2 activation. Under continuous-flow conditions, the optimized NM3 catalyst delivers a high CO production rate of 181.18 mmol/(g & sdot;h) at 220 degrees C, while maintaining excellent stability, water resistance, and recyclability. Combined experimental analyses and DFT calculations suggest that amino-functionalizationinduced defect engineering effectively modulates the electronic structure of NH2-MIL-125(Ti), modulates the electronic structure and contributes to enhanced photothermal catalytic performance, and promotes synergistic photothermal catalytic behavior. This study highlights defect engineering via functional group regulation as an effective strategy to overcome intrinsic limitations of MOF-based catalysts and provides practical insights for the development of efficient and durable photothermal systems for CO2 conversion into fuels.

Vessel Speed Reduction (VSR) lowers ship CO2 emissions, but its aerosol consequences remain poorly constrained. Combining unmanned aerial vehicle (UAV) plume interception, single-particle mass spectrometry (SPMS), and population-balance inversion across 14 ship plumes, we reconstructed ultrafine and coarse modes and identified two marker gaps. Only 35.8% of the reconstructed particle-number population carried detectable V (29.5% at 4.9 versus 39.7% at 13.4 knots in a matched-vessel pair; 0–70.8% across a speed-blind manifold), showing operation-dependent marker coverage. Approximately 20% of analyzed particles met SPMS biomass-burning criteria, indicating potential false positives in ship-influenced samples. Plume-stratified analysis found 2.3–10.7-fold higher median sulfate-related ion signals in V/VO-bearing particles. Independent V–S co-location supports an association potentially arising from V-associated sulfur chemistry during exhaust cooling, pre-existing SO3 uptake, or terminal co-deposition; laser desorption/ionization matrix effects may contribute to the contrast. In the matched-vessel case, VSR’s CO2 benefit coincided with a carbon-rich particle shift, altered V/VO–sulfur signatures, and lower strict detectable-V coverage. This indicates a potential aerosol-composition and marker-reliability trade-off missed by bulk-mass metrics, with implications for hazard-relevant compositional indicators.

Stir-fry cooking (SFC) is a common food preparation method in Chinese cities, but its contribution to indoor air pollution and related health effects on a national scale remains unclear. Here, we evaluate SFC emissions and health impacts on urban indoor air quality and population health in Chinese cities using PM2.5 measurements in 94 households across 15 Chinese cities over one year. By decomposing the observed time series data of indoor PM2.5 into contributions from SFC, outdoor-to-indoor infiltration, and other indoor sources, our results show that SFC raises indoor PM2.5 levels in kitchens and living rooms by 21% and 7%, respectively. Taking both indoor and outdoor exposure into consideration, the disability-adjusted life years (DALYs) attributable to PM2.5 with SFC or without SFC were 15.1 (95% CI: 10.2-20.1) million years or 13.7 (95% CI: 9.0-18.6) million years, respectively. Females and the elderly are more affected. Proper use of ventilation reduces these impacts, but many households still face elevated risks. Our findings highlight the health challenges posed by indoor air pollution from SFC and suggest that improved ventilation, less frequent stir-frying, and use of air purifiers or face masks can help lower these risks.

Peroxyacetyl nitrate (PAN) is an important tracer of photochemistry formed through the oxidation of nonmethane volatile organic compounds (NMVOCs) in the presence of nitrogen oxides (NO x equivalent to NO + NO2). We use CrIS satellite observations and GEOS-Chem simulations to identify a persistent hotspot of free tropospheric PAN over the Sichuan Basin (SCB) in China during winter. The basin topography promotes the initial vertical lifting, while the subsequent temperature inversion layer in the free troposphere (FT) traps the lifted NO x and NMVOCs, thereby facilitating PAN formation. Budget analysis for a 3-D box representing the SCB FT (825-215 hPa) shows that photochemical production accounts for 73% of PAN formation, while vertical transport from below contributes 27%. Dominant photochemical PAN formation stems from stagnant air masses enabling sufficient oxidation of precursors and low winter temperatures prolonging PAN lifetime. Horizontal transport dominates PAN removal (50%), suggesting the SCB as a winter source of PAN and NO x to downwind regions. This study highlights that meteorology and terrain drive severe winter PAN pollution in the SCB.

Black carbon is a short-lived climate forcer that occurs as a continuum of particulate matter with varying physical, chemical and optical properties. However, current global climate assessments treat black carbon as a single compound, overlooking the distinct properties of its subtypes and introducing substantial uncertainty in determining its climate impact. Here we evaluate the climate relevance of this overlooked heterogeneity using approximately 2,500 thermal–optical measurements of carbon fractions across emission sources to develop a global inventory distinguishing between less light-absorbing char and more light-absorbing soot from 1750 to 2019. We observed an increase in the soot fraction of total anthropogenic black carbon emissions, from 16% in 1750 to 35% in 2019, primarily driven by increased fossil fuel consumption. This shift, aligning with sediment records, suggests that contemporary black carbon emissions possess greater global warming potential per unit mass than those at the onset of the industrial era. Our findings underscore the need to resolve black carbon subtypes in climate models and prioritize soot-rich sources for mitigation. The soot fraction of global black carbon emissions increased from 16% in 1750 to 35% in 2019, mainly driven by fossil fuel consumption, suggesting a higher warming potential per unit mass, according to an analysis of atmospheric measurements.

Aerosol acidity plays a crucial role in multiphase atmospheric chemistry, influencing aerosol composition, gas-particle partitioning, and the oxidative capacity of atmosphere. However, the mechanisms governing aerosol acidity in coastal areas under extreme weather remains challenging due to the complexity of atmospheric transport. Here, we investigate aerosol pH in Shenzhen, a coastal megacity in China, by integrating field observations with multiphase buffer theory and ISORROPIA simulations. Our observations captured both a typhoon episode and typical non-typhoon periods with two contrasting regimes: during non-typhoon periods, aerosols were consistently buffered by the NH4+/NH3 pair, with relative humidity serving as the primary driver of pH variability, enabling reliable predictions using multiphase buffer theory. In contrast, during a typhoon episode, nonvolatile cations derived from sea salts emerged as the dominant drivers, violating the charge balance for NH4+/NH3 buffering and leading to poor performance of buffer theory. ISORROPIA simulations under the assumption of constant aerosol water content reproduced the observed pH more reliably, highlighting a compositional rather than meteorological control. Our results provide direct field-based evidence for regime shifts in aerosol acidity regulation in coastal regions and underscore the need for chemical transport models to account for composition-meteorology interactions to improve acidity predictions under extreme weather events.

Suburbs of Jinan, a major city in eastern China, have experienced severe O3 pollution in recent years; thus, clarifying the key driving factors of its formation is essential for suppress the deterioration of O3 pollution. This study ensemble the Light Gradient Boosting Machine (LightGBM) model, combined with Shapley Additive Explanations (SHAP) and positive matrix factorization (PMF), to investigate the impacts of various factors including meteorological conditions, chemical compositions, and emission sources on ozone formation during June October 2024, specifically on polluted days and during typical persistent pollution events. SHAP analysis revealed that meteorological factors accounted for 50.1% of O3 variability, with temperature and relative humidity being the main driving factors. When the temperature exceeds 20 degrees C, it promotes O3 formation, while relative humidity above 65% exerts an inhibitory effect. Chemical factors accounted for 49.9% of the impact on ozone, where volatile organic compounds (VOCs) was the main factor. Solvent volatilization, vehicle emissions and PM2.5, showed a positive response to O3 formation, while NO2 exhibited a negative response. During ozone pollution, the impacts of vehicle emissions increased by 74.6%. Case studies of four O3 pollution episodes confirmed vehicle emissions as persistent chemical contributors, while the roles of NO2, industrial sources, and PM2.5 varied with conditions. Our finding revealed that the combination of the LightGBM model and SHAP analysis could provide a reliable method for rapid diagnosis of the cause of O3 pollution at different event scales, supporting the formulation of control measures.

As global warming intensifies, humid ecosystems are increasingly exposed to unexpected extreme droughts. However, it remains unclear how ecosystem functions, such as greenness and photosynthesis, and structures, such as leaf area, respond to such events and whether they decouple. We investigated the record-breaking 2022 growing-season drought in the humid Yangtze River Basin, where precipitation dropped similar to 50% below average. Here we analyzed anomalies of remote sensing normalized difference vegetation index (NDVI) and solar-induced fluorescence (SIF) to indicate ecosystem functional responses, and leaf area index (LAI) to represent ecosystem structural responses. We applied machine learning models and SHapley Additive exPlanations (SHAP) analysis to attribute these responses to hydroclimatic anomalies and further examine topographic effects. Results indicate a striking divergence of ecosystem functional and structural responses, with NDVI decreasing by 8.4% and SIF declining by 2.2%, while LAI increasing by 1.8% relative to history (2001-2022). Notably, subtropical forest LAI surged by 9.8%, despite a marked decline in NDVI and SIF. Leaf growth was enhanced especially at higher elevations with dense canopies and abundant antecedent soil moisture. Energy conditions, that is, air temperature, vapor pressure deficit, and solar radiation, were found to strongly regulate ecosystem responses to drought. These results imply that humid ecosystems can sustain structural growth despite functional impairment under drought, likely through complex physiological regulation and complementary resource utilization. Our findings underscore the importance of incorporating the function-structure decoupling under extreme drought in photosynthesis and terrestrial carbon cycle estimations.

Phenol is a refractory organic pollutant, and developing efficient catalysts for its degradation is still a challenge. Conventional advanced oxidation processes have limitations in electron transfer rate and pH adaptability. We synthesized a tungsten-doped cobalt sulfide catalyst via a hydrothermal method for activating peroxymonosulfate (PMS) to degrade phenol. Under optimal doping conditions, the CW-1/PMS system achieved 100% phenol removal, with an 8-fold increase in the reaction rate constant compared to the undoped catalyst. Tungsten doping effectively promoted electron transfer and accelerated the Co3+/Co2+ redox cycle. The system maintained high efficiency over a wide pH range and in the presence of common anions, though it was significantly inhibited by humic acid, demonstrating good environmental adaptability. The degradation pathway was elucidated by high-performance liquid chromatography-mass spectrometry (HPLC-MS) combined with density functional theory (DFT) analysis. The Ecological Structure-Activity Relationships (ECOSAR) model and phytotoxicity experiments indicated a significant reduction in the toxicity of the degradation products. This work provides theoretical insights and technical guidance for designing efficient catalysts and treating phenol-containing wastewater.