Atmospheric Environment最新文献

{"title":"Divergent mechanisms govern N2O emissions from Qinghai-Tibet Plateau alpine meadows in freeze versus thaw periods","authors":"Yali Liu ,&nbsp;Junfeng Wang ,&nbsp;Qingbai Wu ,&nbsp;Dan Xue ,&nbsp;Huai Chen","doi":"10.1016/j.atmosenv.2025.121510","DOIUrl":"10.1016/j.atmosenv.2025.121510","url":null,"abstract":"<div><div>Substantial nitrous oxide (N₂O) emissions from permafrost-affected regions could accelerate climate warming, given that N₂O exhibits approximately 300 times greater radiative forcing potential than carbon dioxide. Pronounced differences exist in N₂O emissions between freeze and thaw periods (FP and TP), but the mechanisms by which environmental factors regulate the production and emission of N₂O during these two periods have not been thoroughly examined. We therefore combined static chamber gas chromatography, in-situ soil temperature (ST) and moisture (SM) monitoring, and 16S rRNA sequencing to investigate seasonal N₂O variations in the Qinghai-Tibet Plateau (QTP) alpine meadow ecosystem, and assess the relative contributions of environmental and microbial drivers. Our findings indicate that N₂O fluxes (−3.15 to 6.10 μg m⁻² h⁻¹) fluctuated between weak sources and sinks, peaking during FP, particularly at its late stage with initial surface soil thawing. Soil properties affect N₂O emissions by regulating denitrification processes and altering microbial community diversity. During the FP, ST fluctuations control N₂O release by modifying mineral nutrient availability. During TP, soil texture modulates denitrification-driven N₂O production through its effect on SM. Spring N₂O pulses likely originate from microbial reactivation in thawed soil. N₂O accumulated in frozen soil may gradually release during vertical profile thawing. On the QTP, a warmer and wetter climate scenario may alter N₂O emissions by modifying the duration of the FP and TP and phase-specific hydrothermal allocation. This study provides mechanistic insights for predicting climate change impacts on N₂O flux in fragile alpine meadow ecosystems.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121510"},"PeriodicalIF":3.7,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144931800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of oil and gas emissions on summertime air quality in the Northern Great Plains: WRF-Chem modeling analysis","authors":"Carlos J. Bucaram ,&nbsp;Frank M. Bowman","doi":"10.1016/j.atmosenv.2025.121509","DOIUrl":"10.1016/j.atmosenv.2025.121509","url":null,"abstract":"<div><div>Oil and gas production increased dramatically last decade in the Bakken region, with accompanying changes to pollutant emissions and atmospheric concentrations. WRF-Chem model simulations of the Northern Great Plains were conducted comparing two emission scenarios using 2011 emissions to represent a baseline case with relatively low oil production (&lt;0.4 million barrels per day) and 2014 emissions to represent a high production case (&gt; 1.0 million barrels per day). Assessment of model predictions from the baseline scenario against ground level meteorology and air quality measurements showed good overall agreement, demonstrating suitable model performance for assessing the effect of emissions changes on pollutant levels. In the high production scenario emissions of SO₂ and NO_x were lower across most of the domain (-80% and -37%, respectively), but were significantly higher in the Bakken region (+62% for SO₂ and +110% for NO_x), and changes in VOC emissions were also relatively higher in the Bakken. Simulated pollutant concentrations followed these emission changes, with average NO_x levels decreasing for the high production scenario by 22% in the overall domain, but increasing by 72% in the Bakken. Predicted average O₃ levels increased slightly by 0.2% across the domain as NO_x levels decreased, characteristic of VOC-limited conditions, with larger increases in urban areas where NO_x reductions were greater. For the Bakken, simulations predict localized O₃ decreases in the center of the region, but increases in downwind areas. Changes between the baseline and high production scenarios demonstrate the influence of oil and gas production associated emissions on pollutant concentrations.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121509"},"PeriodicalIF":3.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145003608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An outcome-wide analysis of maternal air pollution exposure and adverse pregnancy outcomes in intrahepatic cholestasis of pregnancy","authors":"Xueqi Li ,&nbsp;Xiuling Zhu ,&nbsp;Daijuan Chen ,&nbsp;Yajie Zhao ,&nbsp;Xixi Deng ,&nbsp;Yongchi Zhan ,&nbsp;Bing Guo ,&nbsp;Tingting Xu ,&nbsp;Xiaodong Wang","doi":"10.1016/j.atmosenv.2025.121511","DOIUrl":"10.1016/j.atmosenv.2025.121511","url":null,"abstract":"<div><h3>Background</h3><div>While evidence shows that ambient air pollution negatively impacts pregnancy outcomes, its effect on pregnancy outcomes in intrahepatic cholestasis of pregnancy (ICP) patients remains underexplored.</div></div><div><h3>Methods</h3><div>We examined pre-pregnancy and gestational exposure to six pollutants (CO, NO₂, O₃, PM_2.5, PM₁₀, SO₂) across six exposure windows in relation to ten pregnancy outcomes in singleton (n = 1, 770) and twin (n = 945) ICP pregnancies. Logistic regression models and outcome-wide analysis were used, with stratification by fetal sex and ICP severity based on total bile acids (TBA) levels using a restricted cubic spline (RCS) model.</div></div><div><h3>Results</h3><div>SO₂ displayed significant effects on preterm birth and neonatal intensive care unit (NICU) in both singleton and twin pregnancy. Exposure to PM_2.5, PM₁₀ and SO₂ before pregnancy increased the risk of NICU admissions. Twin pregnancies and higher severity of ICP exhibit greater susceptibility to air pollution. Outcome-wide analysis found PM_2.5, SO₂, and O₃ significantly impacted adverse outcomes in singletons, while PM_2.5, SO₂, CO, NO₂, and O₃ had more impact in twins.</div></div><div><h3>Conclusion</h3><div>Air pollutant exposure increases the risk of adverse pregnancy outcomes in ICP, varying by exposure window, fetal sex, and ICP severity. Key pollutants like PM_2.5, SO₂, and O₃ impact both singleton and twin pregnancies.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121511"},"PeriodicalIF":3.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144925819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Driving factors of HONO and their synergy in Hohhot, a semi-arid city in northern China: Insights from interpretable machine learning approaches","authors":"Yitian Gong ,&nbsp;Haijun Zhou ,&nbsp;Xingjun Zhou ,&nbsp;Wenjing Sun ,&nbsp;Bing Sun ,&nbsp;Xi Chun ,&nbsp;Zhiqiang Wan ,&nbsp;Qili Dai ,&nbsp;Yinchang Feng","doi":"10.1016/j.atmosenv.2025.121512","DOIUrl":"10.1016/j.atmosenv.2025.121512","url":null,"abstract":"<div><div>Nitrous acid (HONO) serves as the key source of hydroxyl radicals (OH) in the atmosphere, significantly impacting atmospheric photochemical reactions and air quality. However, the source and formation process of HONO are influenced by numerous factors, and their synergy leads to a limited understanding of its formation mechanisms. In this study, we utilized a random forest (RF) model to elucidate the nonlinear relationships between these driving factors and HONO concentrations in winter and summer. To gain further insights, we combined RF model with SHapley Additive exPlanations and Partial Dependence Plot methods to reveal the sources, driving factors, and their synergy. The findings suggest that HONO is primarily driven by both primary emissions and NO₂ transformation in winter, but by the heterogeneous transformation of NO₂ in summer. A potential connection exists between winter PM_2.5 pollution and HONO. By limiting primary emissions, HONO concentrations can be reduced, which in turn helps mitigate winter PM_2.5 pollution. To lower HONO levels in summer, a synergistic approach is needed to control both NO₂ and NH₃, particularly under high relative humidity. The findings presented herein enhance our understanding of the HONO formation mechanisms and provide a scientific basis for developing comprehensive air quality improvement strategies.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121512"},"PeriodicalIF":3.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new parameterization of uptake coefficient of SO2 and its impact on sulfate concentration","authors":"Kiyeon Kim ,&nbsp;Kyung Man Han ,&nbsp;Jasper Madalipay ,&nbsp;Seogju Cho","doi":"10.1016/j.atmosenv.2025.121503","DOIUrl":"10.1016/j.atmosenv.2025.121503","url":null,"abstract":"<div><div>Current chemical transport models (CTMs), such as the Community Multiscale Air Quality (CMAQ) model, often struggle to reproduce the peak levels of sulfate accurately due to missing sulfate production pathways. To address this issue, we propose an unaccounted pathway via the heterogeneous reaction of SO₂, implementing a new parameterization of the uptake coefficient of SO₂ (<span><math><mrow><msub><mi>γ</mi><msub><mtext>SO</mtext><mn>2</mn></msub></msub></mrow></math></span>). This parameterization accounts for relative humidity and the mixing ratios of NO₂ and NH₃. When the parameterization was incorporated into the CMAQ model (i.e., EXP), sulfate concentrations increased from 3.85 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ to 4.78 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ during the Korea-United States Air Quality (KORUS-AQ) campaign. These enhancements improved model performance, as shown by a reduction in mean bias (MB) from −1.94 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ to −1.00 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ and an increase in the index of agreement (IOA) from 0.63 to 0.70. Additionally, we investigated sulfate concentrations in the EXP across four seasons to confirm that our approach is broadly applicable and not confined to specific temporal conditions. The results also demonstrated a significant improvement in sulfate prediction accuracy, with MB decreasing from −1.68 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ to 0.18 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ and IOA increasing from 0.65 to 0.69. Notably, the most substantial increases in sulfate concentrations were observed during spring and winter, with enhancements of 1.50 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ (57.9 %) and 3.95 <span><math><mrow><mi>μ</mi></mrow></math></span> g/m³ (213.5 %), respectively. These findings emphasize the importance of utilizing an appropriate <span><math><mrow><msub><mi>γ</mi><msub><mtext>SO</mtext><mn>2</mn></msub></msub></mrow></math></span> to improve the representation of sulfate chemistry in CTMs.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121503"},"PeriodicalIF":3.7,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144922025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of traffic emissions on ozone formation in Hong Kong","authors":"Chenchao Zhan ,&nbsp;Jie Dai ,&nbsp;Fengwen Wang ,&nbsp;Hai Guo","doi":"10.1016/j.atmosenv.2025.121507","DOIUrl":"10.1016/j.atmosenv.2025.121507","url":null,"abstract":"<div><div>Due to its high population density and extensive commercial activity, traffic emissions are the primary source of anthropogenic pollutants in Hong Kong, significantly contributing to ozone (O₃) pollution. This study examined the impact of traffic emissions from ships, vehicles, and aircraft on O₃ levels in Hong Kong using the WRF-Chem model. Currently, traffic sources accounted for about 60 % of NO_x and 40 % of VOCs — the key precursors to O₃ formation in Hong Kong. During the daytime, eliminating traffic emissions led to a reduction in O₃ concentration as a result of decreased photochemical production. However, at night, O₃ concentrations increased due to weakened NO_x titration. On average, the effect of reducing traffic emissions on O₃ levels in Hong Kong varied depending on both the quantity and the ratio of NO_x to VOCs. Among the traffic sources, ships were significant contributors, responsible for 35 % of NO_x and 15 % of VOCs. Eliminating ship emissions shifted Hong Kong from a VOC-limited regime to a transitional regime, resulting in a 0.6 % decrease in O₃ concentration. Conversely, when the NO_x to VOCs ratio was low, as with vehicles (21 % NO_x and 19 % VOCs), or when both NO_x and VOCs emissions were minimal, as with aircraft (6 % NO_x and 2 % VOCs), Hong Kong remained in a VOC-limited regime, and removing these emissions led to a 0.2 % increase in O₃ concentration. Furthermore, significant changes in O₃ concentrations typically occurred downwind of the emission centers under prevailing northeasterly winds. These findings support the dual goals of improving air quality and combating climate change in Hong Kong, and they may be applicable to other coastal cities worldwide.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121507"},"PeriodicalIF":3.7,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study of parameterization schemes for aerosol indirect effects in East Asia based on RegCM4","authors":"Runqi Zhao ,&nbsp;Yaxin Hu ,&nbsp;Bingliang Zhuang ,&nbsp;Yinan Zhou ,&nbsp;Peng Gao ,&nbsp;Heng Cao ,&nbsp;Shanrong Liang ,&nbsp;Tijian Wang ,&nbsp;Shu Li ,&nbsp;Min Xie ,&nbsp;Mengmeng Li","doi":"10.1016/j.atmosenv.2025.121505","DOIUrl":"10.1016/j.atmosenv.2025.121505","url":null,"abstract":"<div><div>Cloud droplet nucleation, effective radius and cloud–water autoconversion rate (<em>P</em>) parameterization schemes are included in the fourth version of the Regional Climate Model (RegCM4). For cloud droplet nucleation, an empirical scheme (GI99), a semiempirical scheme (GH93), and a scheme based on aerosol activation theory (AG00) are involved. For <em>P</em>, a scheme dependent only on the cloud water mixing rate (Default), a scheme involving the droplet growth rate (BR67), a scheme highly correlated with aerosol components (BH94), a scheme weakly dependent on the components (TC80), a scheme involving the droplet size (LB95) and a scheme that derives a formula mathematically (IBS2) are adopted and tested. Dispersion (<em>ε</em>) is important when calculating the effective radius. Effective radius schemes with/without <em>ε</em> effects are further compared. An optimal combination of schemes is proposed. For cloud droplet nucleation, GH93 and AG00 are better. For <em>P</em>, LB95, BH94, and Default schemes could better simulate precipitation. Considering the <em>ε</em> effect would improve simulation accuracy. Overall, the AG00, BH94 and two-parameter-<em>ε</em> schemes are recommended for improving model simulations of precipitation in East Asia. The <em>P</em> schemes are compared when the aerosol 2nd indirect effects are investigated in East Asia. The change of net radiative flux at the top of the atmosphere from the schemes is −3.63 ± 4.05 W m⁻² in central to eastern China. The aerosol 2nd indirect effect is the most significant in the BH94 scheme, with average changes in cloud optical depth, net radiative flux, and precipitation of 1.63, −10.58 W m⁻², and -0.01 mm d⁻¹, respectively.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121505"},"PeriodicalIF":3.7,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using an operational air pollution forecast system for evaluation of local emission abatement policy scenarios","authors":"Krzysztof Brzozowski,&nbsp;Łukasz Drąg","doi":"10.1016/j.atmosenv.2025.121506","DOIUrl":"10.1016/j.atmosenv.2025.121506","url":null,"abstract":"<div><div>Effective policy to reduce urban air pollution requires the identification of appropriate solutions to achieve it. Where funding is limited, interventions should result from a previous analysis of strategic effectiveness. In this work, an air pollution forecasting system was used to assess the effectiveness of strategies for reducing emissions from domestic furnaces; the system facilitates forecasts of average hourly concentrations of pollutants, down to street scale (pedestrian level). The analysis was carried out for a city in which exceedances of the PM₁₀ concentration are recorded, due to emissions from domestic furnaces burning solid fuels. A criterion for identification of local pollution hotspots was proposed, determined as part of the calculations for current emission data (base scenario). The effectiveness of four potential emission reduction scenarios was evaluated. The first two scenarios concern the elimination of a specific centile of the highest emitters among domestic furnaces. Two further scenarios included a reduction of the same total number of sources; however, the distance from the pollution hotspots areas identified in the baseline scenario was used as the emitter elimination selection criterion. The results indicate that for the study area the implementation of any of the scenarios considered would allow the elimination of all existing hotspot areas. Nevertheless, the results indicate variation in the effectiveness of individual scenarios on a city-wide scale in terms of the reduction in the number of exceedances of hourly and daily concentration limits, the impact on air quality and the population exposed to excessive levels.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121506"},"PeriodicalIF":3.7,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical concentration of air pollutants based on unmanned aerial vehicle measurements during the winter period in South Korea","authors":"Hyemin Hwang ,&nbsp;Chan Ju Kho ,&nbsp;Jong-Sung Park ,&nbsp;Jae Young Lee","doi":"10.1016/j.atmosenv.2025.121504","DOIUrl":"10.1016/j.atmosenv.2025.121504","url":null,"abstract":"<div><div>Air pollutant dynamics are influenced by various factors, leading to complex physical and chemical interactions in the atmosphere. Unmanned aerial vehicles (UAVs) enable high-resolution measurements of spatiotemporal variability in air quality across different altitudes and locations. However, comprehensive studies that integrate vertical measurements with detailed analyses of meteorological conditions and impacts of transboundary pollution are lacking. We investigated the relationship between air pollution concentrations measured by UAVs during winter and various meteorological factors. We evaluated the relationship between irradiance and surface wind based on the measured concentrations of gaseous pollutants such as CO, NO₂, O₃, and SO₂, as well as particulate pollutants such as PM_2.5. The influence of long-range transport was assessed by clustering the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) backward air trajectories. Photochemical reactions were most active in the afternoon, resulting in decreased concentrations of CO and NO₂, whereas O₃ concentrations increased. While CO and NO₂ concentrations were influenced by road traffic and the surrounding urban environment, those of O₃ and PM_2.5 were affected by long-range transport. High concentrations of CO, NO₂, SO₂, and PM_2.5 were observed during periods of atmospheric stagnation. This study provides a comprehensive analysis of the relationships among winter air pollutant concentrations, photochemical reactions, atmospheric stagnation, and long-range transport.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121504"},"PeriodicalIF":3.7,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Various formation pathways of size-resolved secondary organic aerosols at a coastal site in Eastern China","authors":"Meng-Xue Tang ,&nbsp;Jia-Yuan Wang ,&nbsp;Ke-Jin Tang ,&nbsp;Wen-Jie Yu ,&nbsp;Li He ,&nbsp;Xiao-Feng Huang ,&nbsp;Ling-Yan He ,&nbsp;Hui Zeng ,&nbsp;Si-Hua Lu ,&nbsp;Min Hu","doi":"10.1016/j.atmosenv.2025.121501","DOIUrl":"10.1016/j.atmosenv.2025.121501","url":null,"abstract":"<div><div>Secondary organic aerosol (SOA) exists across a broad particle size range plays a crucial role in regional air pollution and climate, yet its formation mechanisms under varying meteorological conditions remain poorly understood. In this study, size-segregated aerosol samples (0.056–18 μm) were collected in Jiaxing, a coastal city in eastern China. Samples were categorized into land breeze (LP), sea breeze (SP), and dust event periods (DP). Oxygenated organic aerosols (OOAs) were identified as the dominant component of organic matters across all periods (65.9–81.6 %). Radiocarbon (¹⁴C) analysis revealed that fossil-derived OOA exhibited a dominant contribution to total OOC (78.1 %). High correlations of OOA and O₃ in both fine and coarse modes indicated the important role of gas-phase oxidation across all particle sizes, while a specific association between fine-mode SOA and Fe ions suggested an additional aqueous-phase contribution in the fine mode. During the LP, the relative short transport distance of land air masses resulted in lower oxidation states for both fine and coarse particles, leading to the lowest O/C values. In contrast, during the SP, increased aerosol liquid water enhanced SOA formation, elevating O/C in coarse particles. During the DP, extensive multi-generational oxidation occurred during long-range transport, yielding higher fine-mode O/C. The coarse-mode OOA was positively correlated with Cl⁻ and Ca²⁺, implying heterogeneous formation related to soil dusts. This study highlights the complexity of SOA formation pathways through multiple air mass types and different particle sizes, underscoring the necessity to incorporate various formation pathways into atmospheric models for accurate simulations and policy guidance.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"361 ","pages":"Article 121501"},"PeriodicalIF":3.7,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}