Environmental Science & Technology Letters Environ.最新文献

Formic acid (HCOOH), a key driver of secondary organic aerosol and cloud condensation nuclei formation, is systematically underestimated in atmospheric models due to inadequate source characterization. To address this gap, an integrated field campaign was conducted at a South China Sea (SCS) coastal site during the summer, focusing on gaseous HCOOH (HCOOH_g). Measurements revealed that the average concentrations of HCOOH_g reached as high as 6.7 μg/m³ and 4.0 μg/m³ under land and marine breeze, respectively. On marine breeze days, HCOOH_g exhibited significant correlations with chlorophyll-a (Chl-a) and particulate organic carbon (POC) in seawater, implicating dual production pathways from both biogenic activities of phytoplankton and abiotic processes of dissolved organic matter degradation. Quantification of marine-sourced HCOOH_g revealed that these processes collectively accounted for around 16% of HCOOH_g, with abiotic contributions double the biogenic contributions. Based on the established parametrization linking HCOOH_g to marine tracers (POC and Chl-a), the spatial distribution of marine-sourced HCOOH_g was extrapolated over the SCS, identifying pronounced hotspots in eutrophic coastal regions. This work reveals the coastal eutrophic ecosystem as a pivotal yet unaccounted HCOOH_g source, emphasizing the necessity of coupling the interactions between marine biogeochemical processes and atmospheric chemical components into air quality and climate modeling.

Water-soluble humic-like substances (HULIS) are ubiquitous in the atmosphere affecting air quality and Earth’s radiative balance. However, the molecular composition of ambient HULIS remains poorly constrained. This study employed gas chromatography-orbitrap mass spectrometry to conduct nontargeted molecular characterization of HULIS in ambient PM_2.5 samples. A total of 60–193 organic compounds were identified in HULIS across seasons, and both their quantities (66.7–78.0%) and mass concentrations (75.5–84.6%) were dominated by intermediate-volatility organic compounds (IVOCs). The mass concentrations of IVOCs in both highly oxidized (average carbon oxidation state, $\overline{\mathrm{OS}}$_c > 0) and less oxidized (−1 < $\overline{\mathrm{OS}}$_c ≤ 0) HULIS fractions were approximately four times that in the reduced HULIS fraction ($\overline{\mathrm{OS}}$_c ≤ −1), indicating that the atmospheric oxidation process enhances the dominance of IVOCs in HULIS. Organic acids were the most prevalent substances in IVOCs, accounting for 63.5–78.3% of total IVOC mass concentration in different seasons. Besides, in summer, amines and alcohols also contributed 15.3–17.5% to total IVOC mass concentration, while in winter, N-heterocycles and phenols contributed 16.9–17.5%. This study advances the understanding of the molecular composition of ambient HULIS and highlights the dominance of IVOCs, which enhances the understanding of the atmospheric evolution processes and formation mechanisms of ambient HULIS.

China has implemented stringent emission control measures, but it remains unclear how these measures affect the aging degree of black carbon (BC), a crucial factor influencing its climate and health effects. By introducing a BC aging module into the two-way coupled WRF-CMAQ model, we analyzed the evolution and drivers of BC aging degree from 2013–2019. Results show significant declines in the number fraction of thickly coated BC particles (f_coated) in eastern China, particularly in megacity clusters: the Beijing–Tianjin–Hebei region (−0.17 decade^–1), the Yangtze River Delta (−0.19 decade^–1), and the Pearl River Delta (−0.21 decade^–1). Emission reductions were identified as the predominant factor, accounting for 38–97% of the f_coated reduction. In Beijing and Shanghai, clean air actions have decreased residential contributions to BC emissions, diminishing the initial aging of BC and reducing f_coated by 35–38%. Regionally, rapid declines in precursor gas emissions have reduced BC coating materials, slowing BC aging rate and decreasing f_coated by 31–106%. Our study highlights the critical role of emission controls in mitigating BC aging in China, providing key insights for understanding the effectiveness of air quality policies and their climate and health implications.

Nitrous oxide (N₂O) is a potent greenhouse gas with a global warming potential over 270 times that of CO₂, yet its removal remains challenging due to its high chemical stability. We present a catalyst-free, microbubble-based approach for N₂O decomposition that operates at room temperature. A 3D-printed microbubble generator enables precise control of bubble size to optimize interfacial reactions. In a closed 700 mL system containing 2500 μM N₂O gas, complete decomposition was achieved within 8 h, which is well described by first-order reaction kinetics with a half-life of 2.56 h. For 0.5 μM N₂O, which is close to atmospheric conditions (0.34 μM), a single device processing 3 L/h can achieve 98% removal efficiency within 1 h, and 10 devices can achieve 99% removal of within 15 min in a 3 m³ glovebox. Mechanistic investigations with electron paramagnetic resonance (EPR) spectroscopy and density functional theory (DFT) calculations suggest that the reaction is initiated through electron detachment by the strong electric fields generated on the gas–water interface, which has been extensively studied. This leads to the formation of active intermediates which participate in a cascade of electron transfer and radical reactions, ultimately generating N₂ and O₂ as main products.

Water-soluble polymers (WSPs) are produced and used in large volumes but are exempted from REACH, resulting in a blind spot in chemical regulation. In light of the current revision of REACH, cationic polymers like polyquaternium (PQ) polymers have been flagged as potential “polymers of concern” due to the first evidence of their toxicity and persistence, yet little is known about their environmental occurrence. In this study, a novel approach for WSP trace analysis was adopted for PQs and used to screen for PQ2, -6, -7, and -10 in 15 surface waters taken in the region of Leipzig, Germany. This first environmental data showed a widespread occurrence of PQ2, which was detected in 13 of 15 samples, while PQ7 and -10 were detected in three and four samples, respectively. While accurate quantification is currently not feasible due to a lack of high-quality standards, PQ2 concentrations were estimated to be in the range of 10–1000 μg/L. Based on these estimates, concentrations in eight samples potentially exceed LC₅₀ (rainbow trout and Daphnia magna) and ErC₅₀ (Scenedesmus suspicatus) values reported for PQ2. Due to the complex interactions of PQs with natural organic matter, the extent to which detected PQs are bioavailable and thus may show adverse environmental effects remains unclear.

The air pollutants released during firework displays during the Chinese Lunar New Year have long been a hot topic. However, an overall view of the gaseous and particulate amines released by fireworks is lacking. For the first time, high-frequency measurements of gaseous and particulate (i.e., PM_2.5) amines were conducted at a location near Jiuhua Mountain National Scenic Area. Biomass burning is prohibited in this area, whereas setting off fireworks is allowed during the Lunar New Year. From the clean period to the firework period, mean concentrations of particulate and gaseous amine compounds, along with K⁺, Cl^–, and SO₄^2– (typical firework-related pollutants), increased significantly (3–12 times). In contrast, parameters including oleamide (C₁₈H₃₅NO; a cooking indicator), ammonium, temperature, humidity, and ozone exhibited small fluctuations (∼1-fold). Thus, the outbreak of atmospheric amines (/aminiums) during the Spring Festival can be attributed to fireworks. Monomethylaminium and ethylamine were the dominant gaseous and particulate amines in firework emissions, respectively. Further analysis showed that primary emissions from fireworks, rather than gas–particle partitioning, dominated the differences in major gaseous and particulate amine species. This study presents a new emission source of atmospheric amines, providing novel insights into firework-related pollutants.

Per- and polyfluoroalkyl substances (PFAS) are a global challenge due to their exceptional thermal and chemical durability which leads to environmental persistence, bioaccumulation, and toxicity. Tackling this challenge is a complex endeavor as the ever-expanding number of emerging PFAS hinders their monitoring while current countermeasures remain limited. Thus, there is a need for rapid strategies that can transform PFAS into safer, degradable analogs or expand libraries for untargeted monitoring. Here, we describe the implementation of a high-throughput (1 Hz) desorption electrospray ionization mass spectrometry (HT-DESI-MS) platform for the chemical transformation of perfluorocarboxylic acids (PFCAs) via a data-driven workflow that led to 915 new PFCA analogs (89% success rate) and revealed reactivity trends. Tandem mass spectrometry (MS/MS) enabled online structural confirmation and diagnostic fragment identification, supporting standard-free LC-MS/MS analysis. Further integration with ion mobility spectrometry (IMS) provided drift time measurements correlating with molecular size and shape, adding a new dimension that can improve feature annotation in untargeted PFAS analysis. Complementary quantum mechanical calculations of dipole moment and HOMO–LUMO gap predicted polarity and electronic reactivity, guiding analog selection. Collectively, this workflow combines rapid synthesis, structural annotation, and multidimensional profiling, with potential to discover safer PFAS and enhance environmental monitoring.

Light-mediated inactivation of pathogenic microorganisms is vital to engineering water treatment processes and predicting fate and transport in the environment. However, there is high variability in reported viral photoinactivation rates, even in purported sensitizer-free suspensions. Using bacteriophage MS2 as a model, this study explores the impact of progressive inoculant purification processing by centrifugation, filtration, and ultrafiltration, on photoinactivation rates. Faster inactivation kinetics under UVB radiation correlated with greater presence of background proteins as identified via sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Differences in the determined rate constants were large and statistically significant, nearing a 70% increase from the lowest to highest protein presence. Variations remained even after 100× dilution of viral stock preparations. Furthermore, the likely basis was determined to be an indirect inactivation mechanism via sensitization of host or media proteins in the solution background, as evidenced by the inclusion of singlet oxygen scavenger l-histidine, which resulted in a clustering of reaction rates near the ultracentrifuged sample. These experiments highlight the methodological importance of performing and confirming inoculant purification prior to performing photoinactivation experiments, particularly when isolation of the endogenous pathway is important for practical or mechanistic conclusions, while demonstrating the notable contribution of proteins to the exogenous pathway.

The expansion of offshore wind and marine renewable energy devices (MREDs) is increasing anthropogenic electromagnetic fields (EMFs) from submarine power cables (SPCs). SPC-generated EMFs can exceed 2700 μT, well above the geomagnetic field, and may affect benthic animal behavior. In decapod crustaceans, sex-specific habitat uses and seasonal migrations are well-documented, yet their role in EMF sensitivity remains untested. We exposed juvenile shore crabs (Carcinus maenas) (n = 120; 1:1 sex ratio) to EMFs of 500, 1000, and 3200 μT using a Helmholtz coil system and tracked behavior over 10 min trials. Females exhibited strong attraction across EMF levels, spending up to 131% more time in the EMF-exposed zone and significantly less time in the low-field zone. They also drove differences in distance moved, whereas males showed no consistent spatial preference and indifferent activity at the highest field strength. These sex-specific responses suggest SPC EMFs could disrupt female-driven reproductive behaviors like seasonal migrations and larval release. Attraction may cause disorientation, aggregation, or delays in migration, potentially altering sex ratios and reducing larval export. This study provides the first evidence of sex-specific EMF responses in crustaceans and highlights the importance of incorporating sex as a key variable in ecological risk assessments of offshore infrastructure.