Reactive Evolution of HMML from Gas Phase Formation to Interface Transformation on Sulfuric Acid Aerosols: A Multiscale Computational Study.

Hydroxymethyl-methyl-α-lactone (HMML) is a key epoxide precursor in forming tracer compounds 2-methylglyceric acid (2-MG) or 2-methylglyceric acid sulfate (2-MGOS) from isoprene under high-NOx conditions. Despite its importance, the formation and transformation of HMML─particularly under acidic aerosol conditions─are still poorly understood, limiting comprehensive knowledge of secondary organic aerosol (SOA) formation. In this study, quantum chemical calculations, Born-Oppenheimer molecular dynamics (BOMD), and metadynamics (MTD) simulations are employed to investigate both the formation of HMML from methacryloyl peroxynitrate (MPAN) and its interfacial transformation mechanisms on sulfuric acid aerosols.

Wastewater-based epidemiology empowered by o-DGT passive sampling: Quantifying pharmaceuticals consumption hotspots in rural China's untreated watersheds.

The lack of centralized sewage treatment in rural areas has led to severe underestimation of pharmaceutical pollution, posing significant risks to aquatic ecosystems and human health. While wastewater-based epidemiology (WBE) is widely used to estimate pharmaceutical consumption in urban settings, its dependence on sewage infrastructure leads to monitoring deficiencies in rural watersheds with direct wastewater discharges into rivers. Here, we pioneer the application of organic-diffusive gradients in thin-films (o-DGT) passive sampling to conduct WBE in a representative rural area of Hunan Province, China, which lacks sewage treatment facilities.

Recent progress and future prospects of the early solar system chronology.

We review the developments in isotope chronology of the oldest extraterrestrial materials achieved in the last 10-15 years, with emphasis on high precision U-Pb and extinct radionuclide dating, and on application of these methods to the materials that formed in the first 7 million years after formation of proto-Sun, the time during which the gas and dust in the protoplanetary disc accreted or dissipated, and planetesimals and protoplanets formed. The analytical precision of isotopic dates now allows resolving events that occurred within 100 000-300 000 years of each other. The main challenges currently faced by isotope cosmochronology are matching the achieved precision with a similar level of accuracy, adapting to the growing evidence of complex isotope heterogeneity of the protoplanetary disc, extracting ages of individual events from complex rocks, and responding to growing quantity, quality and diversity of recently discovered meteorites and samples returned by space missions.

Nontarget screening and identification of emerging preservatives and their metabolites in human urine.

Preservatives are widely used in cosmetic and personal care products to prevent microbial contamination and prolong products' shelf lives. However, concerns about human exposure to these chemicals are increasing due to their confirmed and/or potential negative effects on human health. In this study, we developed a nontarget and suspect screening strategy to identify 5 emerging preservatives and their metabolites in human urine using ultra-high performance liquid chromatography coupled with a high-resolution mass spectrometer (UHPLC-Q-Orbitrap HRMS).

Species- and sex-specific bioaccumulation, tissue-specific distribution, and maternal transfer of per- and polyfluoroalkyl substances in tiger frogs (Hoplobatrachus chinensis) and forest frogs (Rana chensinensis).

Amphibians are sensitive biomonitors of environmental pollutants. However, existing research on per- and polyfluoroalkyl substances (PFASs) between different species of amphibians is limited. In the present study, water, soil, tiger frog (Hoplobatrachus chinensis) and forest frog (Rana chensinensis) samples were collected from Qingyuan County, South China.

Improved modelling of biogenic emissions in human-disturbed forest edges and urban areas.

Biogenic volatile organic compounds (BVOCs) are critical to biosphere-atmosphere interactions, profoundly influencing atmospheric chemistry, air quality and climate, yet accurately estimating their emissions across diverse ecosystems remains challenging. Here we introduce GEE-MEGAN, a cloud-native extension of the widely used MEGAN2.1 model, integrating dynamic satellite-derived land cover and vegetation within Google Earth Engine to produce near-real-time BVOC emissions at 10-30 m resolution, enabling fine-scale tracking of emissions in rapidly changing environments.

Secondary organic aerosol in urban China: A distinct chemical regime for air pollution studies.

In the past decades, China has witnessed high air pollution associated with rapid economic development, although regulatory efforts have alleviated the situation since 2013. Haze events characterized by high particulate matter (PM) levels in China are not only of enormous magnitude but also represent a distinct chemical regime. Once driven by direct emissions, these high-PM episodes are now more affected by secondary aerosol, especially secondary organic aerosol (SOA).

The source and thermal driver of young (<3.0 Ga) lunar volcanism.

The thermal mechanism that drives the prolonged volcanism on the Moon, especially after the major pulse of Imbrian-aged eruptions, remains unknown. Here, we present a petrological and geochemical study of two types of young farside mare basalts, the ~2.8-billion year (Ga) low-Ti and ~2.

Substantial reductions in black carbon from both fossil fuels and biomass burning during China's Clean Air Action.

Black carbon (BC) aerosols exacerbate air pollution and climate warming, but their climatic impacts and sources are poorly constrained by bottom-up emission inventories (EIs). China's Clean Air Action (CAA), which was launched in 2013, provides an excellent opportunity for investigating interannual variations in source contributions and validate the accuracy of EIs. Here, we present an 11-y (2008-2018) record of the BC concentration and its source-diagnostic radiocarbon (C) and stable carbon isotope (C) signatures at a receptor site in the Pearl River Delta (PRD) region, South China.

A novel method for high-precision tungsten isotope measurements on small-size samples.

The application of Hf - W system for accurate dating and tracing of planetary events relies on highly accurate and precise tungsten isotope measurements. However, high-precision measurement of W isotopes usually requires large samples, which greatly hampers the study of low-content and/or small-size samples. In this study, a two-column W purification procedure was developed for small-size samples with the whole procedure blank of less than 40 pg and the recovery greater than 97 %.

Quantification and molecular characterization of dissolved organic carbon released from leaf fragments, crop straw, and straw biochar.

Dissolved organic matter (DOM) is ubiquitous in the environment and plays an important role in global ecosystems. However, our understanding of the evolution and molecular diversity of DOM from different biomass materials and biochar is not enough. Herein, we investigated the changes in DOM from seven biomass and biochar samples over a bio-incubation of 28 days, and explored their contents, and optical, chemical, and molecular characteristics.

pH-dependent reaction kinetics between glyoxal and ammonium sulfate in simulated cloud droplets.

Aqueous-phase reactions between carbonyls and reduced nitrogen compounds play a considerable role in the formation of secondary organic aerosols and brown carbon in the atmosphere. However, the reported reaction rate constants for these reactions have largely been limited to bulk aqueous-phase simulations, which may not accurately represent the real state of atmospheric cloud droplets. We employed an integration of optical tweezers and Raman spectroscopy to manipulate and analyze simulated cloud droplets (size range 8000-10,000 nm), comprising a mixture of glyoxal and ammonium sulfate.

Formation and stability of environmental persistent free radicals (EPFRs) from the reaction between phenolic compounds and Fe(III)-loaded particles.

Environmentally Persistent Free Radicals (EPFRs) are defined as a new type of pollutant, which can cause environmental pollution and do harm to human health. However, few studies have comprehensively explored the formation conditions and mechanism of EPFRs. This study investigated the EPFR formation abilities and mechanisms of two organic phenolic precursors (4-tert-butylcatechol, TBC, and catechol, CT) on model particulate matter (Fe(III)-loaded SiO and kaolin) using electron paramagnetic resonance (EPR) in combination with Fourier-transform infrared attenuated total-reflectance spectroscopy (FTIR-ATR) and Gas Chromatography-Mass Spectrometry (GC-MS) techniques.

Emerging and Legacy Traffic-Related Nitrogen-Containing Organic Compounds (TNOCs) in Pregnant Women: Exposure Levels, Seasonal Variation, and Health Risks.

As policymakers increasingly promote emission control technologies and the use of electric vehicles, urban traffic pollution patterns are shifting. Traffic-related nitrogen-containing organic compounds (TNOCs), which represent a critical yet underexplored group of chemicals, have not been comprehensively monitored in humans, particularly among sensitive populations such as pregnant women. In this study, we assessed the internal exposure of pregnant women to 20 emerging and legacy TNOCs by analyzing urine samples after deconjugation ( = 400).

Drying Induces Different Effects on the Selective Adsorption of Cd(II) and Zn(II) on Ferrihydrite and Kaolinite.

Soil minerals are important natural adsorbents that regulate heavy metal fate; yet, the influence of natural drying on their adsorption behavior remains poorly understood. This study compared how drying affects Cd(II) and Zn(II) retention and selectivity on two widespread soil minerals, ferrihydrite (Fhy) and kaolinite (Kln), using single/binary adsorption experiments. Results indicated that drying significantly enhanced Cd(II) and Zn(II) retention on Fhy by promoting inner-sphere complexation and enhancing the stability of metal-mineral bonds, as evidenced by extended X-ray absorption fine structure (EXAFS) spectroscopy analyses.

Bias in the estimated association between all-cause mortality and long-term exposure to a specific chemical component of fine particulate matter: The example of black carbon.

Introduction: Long-term exposure to fine particulate matter (PM) has been linked to many adverse health outcomes, which can vary significantly depending on the chemical profile of the PM. However, many meta-analyses of the health effects of a specific component of PM have ignored the effects of other components, leading to omitted variable bias (OVB). This study developed a new method to address this problem and conducted a simulation using black carbon (BC) as an example.

Lens effect of remnant blocks on deep mantle upwelling causing anomalous subsidence.

Classical mantle convection models predict a broad surface uplift over a lower mantle upwelling. However, recent studies have identified anomalously localized surface subsidence above seismically imaged lower mantle upwellings, particularly in regions where upwellings are impeded by subducted/delaminated blocks not currently connected to a subducting/delaminating lithosphere ('remnant blocks' for simplicity), e.g.

Decoding periodate-driven phototransformation of dissolved organic matter in sunlit waters: Multidimensional property shifts and molecular network reconfiguration.

Residual periodate (PI) from advanced oxidation processes poses emerging threats to aquatic carbon cycling, yet its role in reprogramming the phototransformation of dissolved organic matter (DOM) remains poorly understood. Here, we reveal the multidimensional effects of PI residues (20.0-300.

Multiple spectroscopic insights into the coupling effect of transition metals and water-soluble organic compounds on the oxidative potential of PM during haze and clean days.

Transition metals (TMs) and water-soluble organic compounds (WSOCs) are essential contributors to the oxidation potential (OP) of PM. However, the interaction laws between WSOCs and TMs, as well as their coupling effect on OP in complex aerosol liquid phase still remain unclear, leading to huge uncertainties in assessing the health risks of PM. In this study, the coupling effects of WSOCs and TMs on OP were assessed via a cell-free assay of 2',7'-dichlorodihydrofluorescein (DCFH).

Dose-dependent molecular composition of dissolved organic matter in biochar-amended manure composts.

Biochar (BC) amendment is a promising strategy for enhancing compost humification, yet its dose-dependent effects on the molecular-level characteristics of dissolved organic matter (DOM) remain unclear. This study systematically investigates the molecular composition of DOM in compost amended with 0 % (CK), 1 % (T1), 2 % (T2), and 5 % (T5) BC. Elemental analysis revealed a progressive increase in N content from 3.

Tracing anthropogenic contamination in a riverine source-reservoir continuum: Insights from molecular markers.

Anthropogenic contamination poses a growing threat to water quality, yet most studies focus on discrete river segments rather than entire hydrological continuums where contaminant transformation occurs. This study explored this gap by investigating the spatial distribution, sources, and transport pathways of organic pollutants across a complete hydrological continuum, using the Xinfengjiang Reservoir Basin as a case study. Sampling sites were classified into three hydrological units: riverine sources, watercourses and reservoir.

Comparison of Heavy Metal Pollution, Health Risk, and Sources Between Surface and Deep Layers for an Agricultural Region Within the Pearl River Delta: Implications for Soil Environmental Research.

During the past decades, agricultural soil heavy metal pollution has been becoming increasingly severe due to urbanization and industrialization. However, the impact of externally input heavy metals on deep soils remains unclear because most previous relevant research only focused on surface soils. In the present study, Concentrations of eight heavy metals (Cu, Zn, Ni, Pb, Cr, Cd, As, and Hg) were determined for 72 pairs of surface and deep soil samples collected from an agricultural region close to the Pearl River estuary.

Seasonal bioaccumulation and biomagnification of typical organochlorine pesticides in the Pearl River Estuary, South China.

As a typical organochlorine pesticide, dichlorodiphenyltrichloroethane (DDT) and its metabolites (dichlorodiphenyldichloroethane (DDD), dichlorodiphenylmethane (DDM), dichlorodiphenyldichloroethylene (DDE), and bis(p-chlorophenyl)-chloroethylene (DDMU)) (collectively referred to as DDXs), have been widely detected in the Pearl River Estuary (PRE). However, seasonal variations in land runoff and the transformation of DDXs complicate their bioaccumulation characteristics in the PRE. The present study analyzed the sediment and aquatic organisms from both dry and wet seasons to investigate the seasonal characteristics of bioaccumulation of DDXs in the PRE.

The Intrinsic Link between Optical Properties and Toxicity of Extractable Organic Matter in Combustion Particles: Mediated by Polycyclic Aromatic Compounds.

Organic compounds are important contributors to the optical properties and health effects of combustion-derived particles. However, the connection between optical properties and toxicity of combustion particles remains a matter of little concern. In this study, combustion particles were collected from 11 primary sources, including biomass burning, coal combustion, and vehicle exhaust.