Atmospheric Environment最新文献

{"title":"Quantifying and correcting systematic discrepancies in the comparison between surface CO observations and simulations","authors":"Chengkai Fang ,&nbsp;Zhe Jiang ,&nbsp;Min Wang ,&nbsp;Xiaokang Chen ,&nbsp;Weichao Han ,&nbsp;Tai-Long He ,&nbsp;Yanan Shen","doi":"10.1016/j.atmosenv.2025.121769","DOIUrl":"10.1016/j.atmosenv.2025.121769","url":null,"abstract":"<div><div>Surface observations are crucial for understanding atmospheric pollutant sources and variability. However, interpreting these observations, particularly when comparing them to chemical transport model (CTM) simulations, remains challenging. A key difficulty is the spatial mismatch between model resolutions and the point measurements from surface stations. To mitigate this issue, we developed a deep learning (DL)-based method to quantify systematic discrepancies between surface carbon monoxide (CO) observations and GEOS-Chem model simulations across China during 2015–2022. Our method generated daily correction factors for adjusting modeled CO concentrations. Validation demonstrated good consistency between the observed-to-modeled (Obs/GC) concentration ratios and the derived correction factors, with correlation coefficients (<em>R</em>) ranging from 0.85 to 0.93. Our analysis reveals broadly uniform negative correlations between correction factors and observed CO concentrations across eastern China, suggesting that systematic discrepancies decrease with increasing local emissions. In contrast, positive correlations prevail in western China. Furthermore, significant temporal variability in systematic discrepancies was identified at seasonal scales, emphasizing the need for time-dependent dynamic corrections. Applying the DL-based correction approach to GEOS-Chem-simulated surface CO concentrations for 2015–2022 led to a significant improvement in model-observation agreement: <em>R</em> values increased from 0.30–0.43 to 0.63–0.70 (spatial consistency) and from 0.15–0.49 to 0.62–0.81 (temporal consistency). This work provides a novel data-driven approach for correcting systematic discrepancies in model/observation comparisons, which is important for more accurate interpretation of surface observations.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"368 ","pages":"Article 121769"},"PeriodicalIF":3.7,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923088","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":"Source apportionment of fine and coarse particulate matter in Hong Kong and its implications to PM10 air quality management","authors":"Yee Ka Wong ,&nbsp;Kin Man Liu ,&nbsp;Claisen Yeung ,&nbsp;Kenneth K.M. Leung ,&nbsp;Jian Zhen Yu","doi":"10.1016/j.atmosenv.2025.121763","DOIUrl":"10.1016/j.atmosenv.2025.121763","url":null,"abstract":"<div><div>Effective control of ambient respirable particulate matter (PM₁₀, particles with aerodynamic diameters less than 10 μm) is essential for air quality management for public health protection. Achieving this requires targeted strategies that address both fine particles (PM_2.5, less than 2.5 μm) and coarse particles (PM_coarse, between 2.5 and 10 μm). In this study, we conducted a two-year field monitoring campaign in an urban residential area in Hong Kong to simultaneously characterize the chemical compositions and sources of PM_2.5 and PM_coarse. Nearly half (46 %) of PM₁₀ mass was associated with PM_coarse, with individual species exhibiting distinct distribution patterns across the two size fractions. Transition metals known for their roles in PM oxidative potential (e.g., Mn and Cu) were found to be evenly distributed between fine and coarse modes, underscoring the need for further assessments of their size-resolved health effects. Source apportionment using positive matrix factorization showed that PM_2.5 was mainly influenced by secondary sulfate and nitrate formation, road traffic and biomass/coal combustion, whereas PM_coarse was dominated by soil/industrial dust, construction/copper-rich dust and sea salt. Backward air mass trajectory analysis identified a 28 μg/m³ increase in PM₁₀ source contribution under continental air mass influences compared to marine air masses. Coarse-mode soil and industrial dust, primarily transported from inner-continental regions, accounted for 40 % of this excess contribution. This work highlights the growing importance of addressing PM_coarse on a regional scale in future air quality research and control strategies to meet PM₁₀ air quality targets.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"368 ","pages":"Article 121763"},"PeriodicalIF":3.7,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882718","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":"Contrasting pathways of spring black carbon pollution in Northeastern Sichuan basin: Biomass burning transport versus local fossil fuel accumulation","authors":"Pei Tang ,&nbsp;Shiyong Shao ,&nbsp;Jie Zhan ,&nbsp;Liangping Zhou ,&nbsp;Zhiyuan Hu ,&nbsp;Yuan Mu ,&nbsp;Liwen Ye","doi":"10.1016/j.atmosenv.2025.121765","DOIUrl":"10.1016/j.atmosenv.2025.121765","url":null,"abstract":"<div><div>Liangping District, located in the northeastern part of the Sichuan Basin (SCB), is a representative site for studying black carbon (BC) aerosol pollution within the basin. Field measurements of BC mass concentration were conducted continuously from March to May 2021 using an Aethalometer (AE33). The mean BC mass concentration was determined to be 2.4 μg m⁻³. The aerosol optical properties were derived through application of the Aethalometer model, yielding an average absorption coefficient of 36.7 ± 20.1 Mm⁻¹ at 520 nm with a corresponding absorption Ångström exponent (AAE) of 1.40 ± 0.12. During the observation period, two six-day pollution events (designated as Event Mar and Event May) were recorded, with PM_2.5 concentrations exceeding the first-class ambient air quality standards threshold of 35 μg m⁻³. The maximum AAE was 1.70 during Event Mar compared to 1.43 during Event May. The elevated AAE value in Event Mar suggested increased biomass burning constituted a significant pollution source, whereas the lower AAE during Event May reflected a mixed source dominated by fossil fuel combustion. Non-parametric wind regression (NWR) analysis revealed that high BC concentrations were spatially concentrated in the southwestern region during Event Mar, whereas during Event May, elevated BC levels originated from multiple directions. Concentration-weighted trajectory (CWT) analysis indicated that during Event Mar, long-range transport played a more dominant role, whereas local emissions were the primary pollution source during Event May. The study of the two pollution events identified the primary sources of BC, providing a method for analyzing the characteristics of aerosol pollution in SCB and offering a basis for developing pollution control measures.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"368 ","pages":"Article 121765"},"PeriodicalIF":3.7,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145876725","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":"Quantifying source-specific formaldehyde contributions to photochemical oxidant formation in a highly polluted Chinese megacity","authors":"Yunxiang Zhang ,&nbsp;Jie Tao ,&nbsp;Panru Kang ,&nbsp;Dong Zhang ,&nbsp;Yifei Xu ,&nbsp;Mingkai Wang ,&nbsp;Shenbo Wang ,&nbsp;Ruiqin Zhang","doi":"10.1016/j.atmosenv.2025.121762","DOIUrl":"10.1016/j.atmosenv.2025.121762","url":null,"abstract":"<div><div>Formaldehyde (HCHO) critically mediates atmospheric photochemistry, yet its source-specific impacts remain poorly quantified. Integrating Positive Matrix Factorization and Observation-Based Models, we reveal average HCHO concentrations of 5.6 ± 1.6 ppb during ozone (O₃) episodes in Zhengzhou, China, with 43 % originating from RO· + O₂-driven secondary formation. Anthropogenic emission contributes 49 % (e.g., vehicles: 19 %, industry: 16 %). <strong>Under Zero-HCHO simulations, concentrations of HO₂·, OH·, and RO₂· decreased by 27 %, 20 %, and 12 %, respectively, with a concomitant 19 % reduction in net O₃ production.</strong> Source-specific HCHO reveals that secondary production dominated both ROx· (44–48 % contribution) and net O₃ (52 % contribution) formation. Notably, biogenic HCHO emissions serve a critical function in daytime photochemical oxidant formation (14–18 %) despite its 7 % HCHO share. Diurnal analysis further identifies morning rush-hour emissions of HCHO from vehicles/industries that act as photochemical primers, boosting 22 % and 15 % O₃ formation, respectively. This study provides the mechanistic, source-resolved quantification of HCHO's role in radical cycling and O₃ formation, establishing a critical link between emission sources and photochemical outcomes for targeted pollution control.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"367 ","pages":"Article 121762"},"PeriodicalIF":3.7,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920694","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":"Comprehensive diurnal and nocturnal surface NO2 concentration retrieval with seamless temporal and spatial coverage","authors":"Yi Zhang ,&nbsp;Lin Zang ,&nbsp;Yuqing Su ,&nbsp;Jingru Yang ,&nbsp;Ying Yang ,&nbsp;Feiyue Mao","doi":"10.1016/j.atmosenv.2025.121764","DOIUrl":"10.1016/j.atmosenv.2025.121764","url":null,"abstract":"<div><div>Near-surface nitrogen dioxide (NO₂) plays a critical role in the formation of acid rain, photochemical smog, and aerosol particles, posing serious risks to public health. Polar-orbiting satellites are conventionally used for large-scale monitoring of NO₂. However, satellite-based NO₂ retrieval techniques predominantly rely on gas absorption within the ultraviolet and visible spectral regions, and thus are unable to capture nighttime NO₂ concentrations. Moreover, deriving NO₂ values in regions blurred by cloud cover or data missing remains a significant unresolved challenge, further complicating efforts to achieve spatially and temporally consistent atmospheric analyses. This study utilizes the thermal infrared absorption band of NO₂ from the Advanced Himawari Imager (AHI) aboard Himawari-8, alongside various auxiliary datasets, to estimate both diurnal and nocturnal near-surface NO₂ concentrations across central and eastern China. To address data missing caused by cloud coverage, a NO₂ inpainting algorithm based on satellite-ground data fusion is proposed. Three kinds of 5-fold cross-validation demonstrate strong agreement between derived NO₂ estimates and in-situ measurements, achieving R² up to 0.85. The retrieval data reveal significant spatial and temporal heterogeneity in ground NO₂ levels across China. Urban centers, particularly large metropolitan areas, display a distinct \"urban island effect\". Diurnal patterns show two distinct peaks around 09:00 and 20:00 local time. Seasonal fluctuations are also evident, with summer recording the lowest NO₂ concentration and winter showing the highest. This study offers new insights into hourly dissolved 24-h cycle surface NO₂ dynamics, potentially advancing real-time pollution monitoring and public health protection.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"368 ","pages":"Article 121764"},"PeriodicalIF":3.7,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923091","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":"Plant uptake and air-soil exchange of PAHs on university campuses: A tale of species differences, mechanisms and seasonal variation","authors":"Fengwen Wang ,&nbsp;Hongtao Si ,&nbsp;Decai Liu ,&nbsp;Jiayan Yu ,&nbsp;Neil L. Rose ,&nbsp;Hai Guo","doi":"10.1016/j.atmosenv.2025.121766","DOIUrl":"10.1016/j.atmosenv.2025.121766","url":null,"abstract":"<div><div>Polycyclic aromatic hydrocarbons (PAHs) are semi-volatile organic pollutants of global concern due to their ubiquity, persistence, potential carcinogenicity, and complex intermedia exchange behaviors. This study investigates the occurrence, composition, and transport mechanisms of PAHs across air, soil, and plants on university campuses with high densities of young adults (aged 18–30). Annual mean concentrations of gaseous ∑₁₆ PAHs (total of 16 USEPA priority PAHs) were 40 ± 14 ng/m³, with 2–3 ring PAHs comprising 59.6 % of the total. Soils accumulated up to 1000 ± 710 ng/g, dominated by 4 ring (37.8 %) and 5–6 ring PAHs (36.5 %). Leaf concentrations averaged 290 ± 160 ng/g, with species-specific accumulation varying up to 5-fold, influenced by wax content (34 ± 28 g/m²), specific leaf area (210 ± 80 cm²/g), and stomatal density (69 ± 38 stomata/mm²). According to McLachlan's framework for semi-volatile organic compounds (SOCs) in plants, dynamic equilibrium between the gaseous phase and plants dominated uptake in spring, autumn, and winter, while atmospheric gaseous deposition was predominant in summer. Mackay's fugacity model indicated that 3-ring PAHs (e.g., acenaphthylene, acenaphthene) showed net volatilization (<em>ff</em> &gt; 0.5), with annual mean fluxes of 368 ng/m²/day (main campus) and 173 ng/m²/day (new campus), whereas 4–6 ring PAHs tended to deposit (<em>ff</em> &lt; 0.5). These findings highlight the importance of considering spatial heterogeneity, species-specific plant traits, and seasonal dynamics when assessing the fate and exposure risks of PAHs in urban green spaces, particularly within densely populated university campuses.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"368 ","pages":"Article 121766"},"PeriodicalIF":3.7,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922705","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":"Improvement of air quality from upgradation of aged diesel vehicles: A case study in Northwest China","authors":"Yonggang Xue ,&nbsp;Gangzhu Zhang ,&nbsp;Liqin Wang ,&nbsp;Long Chen ,&nbsp;Long Cui ,&nbsp;Yu Huang ,&nbsp;Junji Cao","doi":"10.1016/j.atmosenv.2025.121758","DOIUrl":"10.1016/j.atmosenv.2025.121758","url":null,"abstract":"<div><div>Diesel exhaust is key contributor to the atmospheric fine particles and surface ozone (O₃) in China. Upgradation and replacement of aged diesel vehicles would be potential pathways for further improvement of air quality in China. The present study was conducted to evaluate the improvement of air quality by upgradation of aged diesel vehicles in less developed city in Northwest China. It was found that concentrations of PM_2.5 and volatile organic compounds (VOCs) in diesel exhaust were up to 10,000 and 100 times of that in atmosphere, respectively. Ethylene, ethane, acetaldehyde, propylene, acetylene, and acetone are typical markers in the diesel exhaust. After upgradation, PM_2.5 and VOCs were reduced by 66.8 % and 24.0 %, respectively. The reduction efficiencies of PM_2.5 were found to be positive to the loading of fine particles in the diesel exhaust before upgradation. Due to reduction of VOCs, the ozone formation potential and SOA formation potential were estimated to be reduced by 52.0 %–71.0 % and 9.0 %–93.0 %, respectively. The present study indicated high reduction efficiency of PM_2.5, VOCs, and NOx would be expected in the repairing and upgradation of the aged and high emission diesel vehicles, and upgradation or replacement of aged diesel vehicles would be one of the most effective ways for further improvement of air quality in the less developed areas.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"367 ","pages":"Article 121758"},"PeriodicalIF":3.7,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837112","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":"Aerosol optical depth in East Asia from VIIRS, MODIS, and MISR: Evaluation, variability, and meteorological associations","authors":"Jianming Gong ,&nbsp;Xiaofeng Xu ,&nbsp;Zixu Xiong ,&nbsp;Huiling Zhang","doi":"10.1016/j.atmosenv.2025.121760","DOIUrl":"10.1016/j.atmosenv.2025.121760","url":null,"abstract":"<div><div>Aerosol Optical Depth (AOD) is a key parameter for characterizing the radiative forcing of atmospheric aerosols, yet some inconsistencies remain among different satellite products. In this study, Level-2 (L2) instantaneous and Level-3 (L3) monthly AOD products from Visible Infrared Imaging Radiometer Suite (VIIRS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Multi-angle Imaging Spectroradiometer (MISR) were evaluated using observations from eight AERONET sites across East Asia for the period 2012–2023. We further analyzed the spatial distribution patterns and long-term climatological characteristics of AOD in this region. The results show that VIIRS generally exhibits the best overall performance for both L2 and L3 AOD products relative to AERONET, characterized by high correlation coefficients (R = 0.853 and 0.881), large fractions of retrievals within the expected error (75.34 % and 70.27 %), and comparatively low root mean square error (RMSE) and mean bias error (MBE). Nevertheless, the retrieval accuracy still exhibits pronounced regional variations among these satellite products. In desert regions, MISR performs the best with the highest fractions of retrievals within the expected error (65.14 % and 72.86 %), followed by MODIS, while the VIIRS L3 product shows notable overestimation. The consistency between L2 instantaneous retrievals and L3 monthly aggregates also varies considerably across surface types and among the three sensors. Despite these differences, the three satellite products display broadly consistent spatial patterns and temporal evolutions, commonly identifying similar high-AOD regions. On the interannual scale, all products reveal a persistent decline in AOD from central to eastern China (VIIRS: −0.021 a⁻¹, MODIS: −0.023 a⁻¹, MISR: −0.013 a⁻¹) and an increasing trend over the Indian subcontinent (VIIRS: 0.006 a⁻¹, MODIS: 0.008 a⁻¹, MISR: 0.004 a⁻¹). To further elucidate the climatological behavior of AOD and identify the meteorological factors most strongly associated with its long-term variations, a method combining principal component analysis (PCA) and multiple linear regression (MLR) is applied. The results indicate that over land, the AOD climatology and its interannual variability are most strongly associated with boundary layer height, whereas over ocean, AOD is influenced by a more complex combination of meteorological factors.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"367 ","pages":"Article 121760"},"PeriodicalIF":3.7,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837050","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":"Minute-scale point source simulation: Rapid transient impact assessment","authors":"Liang Li ,&nbsp;Chongyu Zhang ,&nbsp;Wei Zhang ,&nbsp;Huaqiao Gui ,&nbsp;Weiwei Xue ,&nbsp;Zheng Shi ,&nbsp;Zifa Wang ,&nbsp;Ting Yang","doi":"10.1016/j.atmosenv.2025.121757","DOIUrl":"10.1016/j.atmosenv.2025.121757","url":null,"abstract":"<div><div>Abrupt or intermittent emissions can significantly increase regional pollutants and dominate short-term variations, but previous simulations usually treated emissions through total amounts and allocation coefficients, making it difficult to effectively characterize their concentration variation features at the minute-scale. This study proposes a rapid simulation framework for minute-scale high-resolution emission modeling under such scenarios. Integrating multisource background emissions, it assessed Hefei Airport impacts (December 2023). Evaluations confirm accurate simulation of meteorological/air pollutant spatial distributions and effective capture of minute-scale emission characteristics. Airport emissions moderately intensified near-surface temperature inversion downwind of Hefei. Near-airport monthly mean NO₂ and NO rose by 4 μg/m³ and 9 μg/m³, respectively. Emissions also impacted a 15 km radius, elevating NO₂ by 0.6–1.8 μg/m³ and NO by 0–2.5 μg/m³. The framework effectively evaluates regional atmospheric impacts from point-source abrupt/intermittent emissions, enabling rapid localized simulations for scientific assessment and prediction to protect air quality and public health.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"368 ","pages":"Article 121757"},"PeriodicalIF":3.7,"publicationDate":"2025-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922708","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":"Characterizing diurnal variations and driving factors of major gaseous pollutants across China","authors":"Junli Liu ,&nbsp;Yang Qian ,&nbsp;Siyuan Wang ,&nbsp;Weiwei Gu ,&nbsp;Danhuai Guo","doi":"10.1016/j.atmosenv.2025.121759","DOIUrl":"10.1016/j.atmosenv.2025.121759","url":null,"abstract":"<div><div>Gaseous air pollutants pose significant threats to environmental quality and public health, with their diurnal variation patterns critically determining human exposure and health risks. However, the spatiotemporal dynamics and driving factors of these variations remain insufficiently understood at the national level. This study characterizes the diurnal variation of four key pollutants (SO₂, NO₂, CO, and O₃), using hourly observations from 1636 monitoring stations across China spanning 2014–2024. By integrating a Light Gradient Boosting Machine (LightGBM) model with SHapley Additive exPlanations (SHAP), we quantified the non-linear contributions of meteorological, topographic, and socioeconomic drivers to pollutant variability, with the robustness of the results verified through spatial sensitivity analysis. The results reveal pronounced spatial and seasonal heterogeneity in diurnal ranges. Specifically, SO₂ is shaped by the synergy of socioeconomic and meteorological factors; NO₂ is dominated by socioeconomic intensity but amplified by plateau meteorology; CO is driven by high-frequency emission cycles such as traffic patterns; and O₃ is strictly regulated by solar radiation and topography. These findings elucidate the distinct roles of emission intensity, atmospheric stability, and chemical processing in shaping diurnal cycles, underscoring the necessity of region-specific and time-targeted mitigation strategies to minimize population exposure and advance precision air-quality management.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"367 ","pages":"Article 121759"},"PeriodicalIF":3.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837111","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}