Atmospheric Chemistry and Physics最新文献

{"title":"Linking molecular composition of organic aerosols to reactive oxygen species formation using an MCR-VK framework","authors":"Fobang Liu,Yun Zhang,Siyao Yue,Helmi-Marja K. Keskinen,Tuukka Petäjä,Markku Kulmala,Pingqing Fu,Thorsten Hoffmann,Kai Wang,Haijie Tong","doi":"10.5194/acp-26-14655-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14655-2026","url":null,"abstract":"Reactive oxygen species (ROS) formation by atmospheric fine particulate matter (PM) is widely implicated in adverse health effects, yet the molecular determinants of particle-level ROS formation remain poorly constrained, largely due to the chemical complexity of organic aerosol (OA). Here, we link ROS formation to molecular-level OA composition by applying a maximum carbonyl ratio-Van Krevelen framework to ambient fine PM collected from four Chinese megacities, a German semi-urban site, a boreal forest, and laboratory-generated secondary organic aerosol (SOA) from multiple precursors. Using ultrahigh-resolution mass spectrometry combined with hydrogen peroxide (H 2 O 2 ) and radical measurements, we show the intrinsic ROS (H 2 O 2  + radicals) formation potential of fine PM is governed by OA composition rather than particle mass. Volume-normalized ROS yields increase with fine PM mass concentration and dominate overall exposure in polluted urban environments. In contrast, mass-normalized ROS yields vary independently of particle loading and are strongly driven by the balance between relative fractions of oxidized organic compounds (RF OOC ) and unsaturated organic compounds (RF UOC ), i.e., RF OOC  / RF UOC . Across urban sites, mass-normalized ROS and H 2 O 2 yields exhibit strong correlations with RF OOC  / RF UOC , establishing this metric as a robust predictor of ROS formation. Remote, biogenic-influenced aerosols exhibit higher RF OOC  / RF UOC and higher ROS yields per unit mass, whereas urban aerosols exhibit the opposite behavior. Laboratory SOA further supports these composition-reactivity relationships, with OOC-rich biogenic SOA exhibiting the highest ROS yields. This study reveals molecular-level characteristics in governing aerosol ROS formation and introduces a framework for assessing health-relevant aerosol oxidative activity of chemically complex OA.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"4 1","pages":"14655-14669"},"PeriodicalIF":6.3,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interacting effects of droplet number and ice formation processes on mixed-phase cold-air outbreak clouds","authors":"Xinyi Huang,Paul R. Field,Ross J. Herbert,Benjamin J. Murray,Floortje van den Heuvel,Daniel P. Grosvenor,Rachel W. N. Sansom,Kenneth S. Carslaw","doi":"10.5194/acp-26-14577-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14577-2026","url":null,"abstract":"Shallow, mixed-phase clouds associated with cold-air outbreak (CAO) events are natural laboratories for studying mixed-phase cloud processes which are important for estimating cloud-phase feedback in the warming climate. Recent studies show that CAO clouds are sensitive to aerosol-cloud interactions and ice formation processes, but many modelling studies perturbed model parameters individually, limiting the investigation of joint effects from multiple processes on cloud properties. Here we investigated how six cloud microphysics parameters jointly affect CAO cloud properties by building model emulators trained on output from perturbed parameter ensembles of a high-resolution regional model. The parameters are cloud droplet number concentration ( N d ), ice-nucleating particle concentration ( N INP ), efficiencies of three secondary ice production processes, as well as the mixed-phase overlap factor (mpof). For the CAO case studied, N d and N INP most strongly control the cloud radiative properties in the stratocumulus region; whereas in the cumulus region, effects from varying N d and mpof are the strongest. Our results show that these parameters have non-linear joint effects such that the magnitude and even sign of cloud responses to a parameter are highly dependent on the values of other parameters. For example, the sensitivity of cloud albedo to increases in N INP varies between near zero to strongly negative across the sampled parameter space. Therefore, perturbing parameters individually is an inadequate method for determining the cloud responses to model parameters. This work demonstrates the power of model emulation and the importance of a full exploration of parameter space in order to understand the factors controlling cloud properties.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"24 1","pages":"14577-14616"},"PeriodicalIF":6.3,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement report: Soil reactive nitrogen gas emissions in the Tibetan Plateau","authors":"Lingling Deng,Yuhan Chen,Chunxiang Ye,Rui Wang,Ruhai Wang,Zehua Fu,Hongfang Zhao,Dianming Wu","doi":"10.5194/acp-26-14617-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14617-2026","url":null,"abstract":"The Tibetan Plateau, highly sensitive to climate change, exerts strong atmospheric oxidation capacity partly through rapid cycling of atmospheric reactive nitrogen (Nr). Soil Nr emissions play a crucial role in atmospheric nitrogen cycling and oxidation capacity, yet their emissions on the Tibetan Plateau remain poorly quantified. Combining dynamic chamber measurements, laboratory analysis, and a parameterized model, we assessed the characteristics, driving factors, spatial distribution and annual emissions of soil Nr in the Tibetan Plateau. We found that the optimum soil fluxes of nitrous acid (HONO), nitric oxide (NO), nitrogen dioxide (NO 2 ), and ammonia (NH 3 ) were 21.6 ± 8.4, 43.7 ± 14.7, 15.8 ± 1.3, and 190.0 ± 116.3 ngNm-2s-1, respectively. These emissions were mainly influenced by soil pH, nutrient content, and microbial community composition. After exposure to atmospheric NO x and ozone (O 3 ), Nr emissions from forest soils were enhanced but those from croplands and grasslands were suppressed. The estimated annual emissions of soil HONO, NO, and NO x from Tibetan Plateau to be 7.0 ± 3.4, 11.6 ± 7.8, and 20.3 ± 7.0 Gg N yr −1 , respectively. Soil HONO emissions contribute approximately 10.5 % of the external (NO x -independent) daytime atmospheric HONO sources and modulate the regional atmospheric chemical balance by elevating the HONO/NOx ratio. Our results provide the first integrated quantification of soil Nr emissions on the Tibetan Plateau and emphasize their importance for regional nitrogen cycling and atmospheric oxidation capacity.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"27 1","pages":"14617-14636"},"PeriodicalIF":6.3,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular evolution of oxygenated organic molecules in a cloud-influenced forested mountain environment","authors":"Yi Zhang,Wei Zhou,Weiqi Xu,Yan Li,Yu Zhang,Zijun Zhang,Bojiang Su,Ning Zhang,Eleonora Aruffo,Junfeng Wang,Piero Di Carlo,Lanzhong Liu,Xiaole Pan,Zifa Wang,Douglas R. Worsnop,Yele Sun","doi":"10.5194/acp-26-14637-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14637-2026","url":null,"abstract":"Atmospheric oxygenated organic molecules (OOMs) link the oxidation of volatile organic compound to secondary organic aerosol formation, yet their molecular evolution in cloud-influenced forested mountain environments remains poorly constrained. Here, gas-phase OOMs were measured using an iodide-adduct chemical ionization mass spectrometer at a high-altitude forested station in southeastern China during autumn 2023. Among the 1503 identified ions, isoprene-derived OOMs were primarily controlled by daytime OH-initiated oxidation, whereas monoterpene-derived OOMs were driven by coupled OH and NO 3 chemistry. Positive matrix factorization identified nine atmospherically relevant OOM factors, revealing that biogenic oxidation dominated OOM production during warm periods (mean temperature ∼20 °C), accounting for 68 %–79 % of the total OOMs, whereas anthropogenic and regional transport factors became prominent during cooler periods (below 15 °C), accounting for up to 63 % of the total budget. Cloud processes exerted a pronounced influence on OOM composition through competitive wet scavenging and multiphase chemistry. During cloud events, isoprene-derived and monoterpene-derived organic nitrates (ISO-ONs and MT-ONs) decreased by 75 % and 46 %, respectively, while the relative contribution of MT-ONs increased from 23 % to 40 %, suggesting different responses of ISO-ONs and MT-ONs to cloud processing. Furthermore, the contribution of sulfur-containing OOMs increased substantially, consistent with a contribution from aqueous/multiphase processing. These results demonstrate that cloud processing influences the composition and sources of OOMs in forested mountain atmospheres and should be considered when evaluating the atmospheric fate of biogenic oxidation products.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"168 1","pages":"14637-14653"},"PeriodicalIF":6.3,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shifting patterns of Ozone Season due to policy and human activity in Beijing between 2013 and 2023","authors":"Qian Li,Xiaofei Dong,Yuanxi Guo,Xiue Shen,Zhang Zhang,Chunsheng Zhao","doi":"10.5194/acp-26-14559-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14559-2026","url":null,"abstract":"Since 2013, Beijing has implemented a series of stringent measures to control air pollution, resulting in significant improvements in air quality. This study examines the decadal evolution of surface ozone in Beijing from 2013 to 2023 against the backdrop of continuous emission reduction policies. The Ozone Season in Beijing exhibited pronounced interannual variability, while linear trend analysis indicated a tendency toward prolonged duration. Low-percentile concentrations of the maximum 8 h moving average ozone (MDA8) showed a statistically significant upward trend, whereas mean and high-percentile values exhibited nonsignificant monotonic trends. The ozone exposure window shifted toward later hours, particularly during the cold season. Diurnal peak concentrations decreased, while trough concentrations increased, leading to a flattened diurnal variation. Furthermore, both the maximum ozone production and loss rates decreased in absolute magnitude, with the production peak tending to occur earlier in the day. These findings establish an observational baseline for understanding urban ozone evolution under intensified emission controls and provide implications for future policy formulation and public health protection strategies.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"14 1","pages":"14559-14575"},"PeriodicalIF":6.3,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical properties and shape-dependent retrievals of the imaginary part of the refractive index of freshly emitted Saharan dust","authors":"Jesús Yus-Díez,Jeronimo Escribano,Marco Pandolfi,Andrés Alastuey,Cristina González-Flórez,Adolfo Gonzalez-Romero,María Gonçalves Ageitos,Matic Ivančič,Martina Klose,Konrad Kandler,Vincenzo Obiso,Agnesh Panta,Cristina Reche,Martin Rigler,Xavier Querol,Carlos Perez García-Pando","doi":"10.5194/acp-26-14531-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14531-2026","url":null,"abstract":"Mineral dust is a major contributor to atmospheric aerosol mass and plays a complex role in Earth's radiation budget. However, large uncertainties remain in quantifying its direct radiative effects, partly because dust absorption is poorly constrained and in situ measurements of freshly emitted dust remain scarce. Here, we present high temporal resolution measurements of dust optical properties collected during active dust emission events in the Moroccan Sahara in September 2019. During dust emission periods, the optical properties aligned with previous Saharan dust studies. Single scattering albedo (SSA) for PM 2.5 (PM 10 ) was 0.95 (0.94) at 370 nm and 0.97 (0.96) at 660 nm. Coarse particles contributed to negative scattering and SSA Ångström exponents (SSAAE), and absorption Ångström exponents (AAE) reached up to 2.5 (2.0), consistent with stronger wavelength-dependent absorption by iron oxides. The asymmetry parameter ( g ) was 0.7 (0.65) at 520 nm, and the backscatter fraction (BF) was 0.11 (0.13), showing coarse dust's impact on scattering. Mass absorption efficiency (MAE) decreased from 0.30 to 0.15 m 2  g −1 at 370 nm with increasing particle size. Mass scattering efficiency (MSE) shifted towards longer wavelengths for larger particles. We further retrieved the imaginary part of the complex refractive index, k , for the PM 2.5 dust-event period under prescribed assumptions for particle shape, particle density, and the real part of the refractive index. For the central density assumption, retrieved k at 520 nm ranged from 0.00104 for spheres to 0.00145 for triaxial ellipsoids, corresponding to a 40 % increase. These results show that particle-shape assumptions can substantially affect retrieved k , and therefore need to be considered when interpreting in situ, remote-sensing, and model estimates of dust optical properties.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"68 1","pages":"14531-14557"},"PeriodicalIF":6.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Turbulent atmospheric particle fluxes in the High Arctic: surface type dependence and variability","authors":"Theresa Mathes,Ian Brooks,Sonja Murto,Michael Tjernström,Julia Kojoj,Paul Zieger,John Prytherch,Birgit Wehner,Andreas Held","doi":"10.5194/acp-26-14507-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14507-2026","url":null,"abstract":"The Arctic is warming at a significantly faster rate than the global average. This is altering the sources and sinks of aerosols, which influence the regional radiation balance and cloud formation. However, direct observations of turbulent particle fluxes over sea ice are scarce, limiting our understanding of the processes that control the exchange of aerosols between the surface and the atmosphere. During the ARTofMELT campaign in spring 2023, five weeks of continuous eddy covariance measurements of turbulent particle fluxes were conducted in the High Arctic to investigate particle sources and sinks over closed ice, leads, and open water. Overall, net particle deposition dominated, with median deposition fluxes of −0.02 (interquartile range −0.10 to 0.04) × 10 6  m −2  s −1 over closed ice. This confirms the role of ice surfaces as a particle sink under low to moderate turbulence. Under strong winds, net particle emission fluxes of up to 0.98×10 6  m −2  s −1 (95 % confidence interval excluding zero) were observed over closed ice surfaces, which are likely linked to processes involving blowing snow. A mixture of emission and deposition was observed over leads and open water surfaces. These observations highlight how surface heterogeneity and turbulence intensity can influence particle exchange in the High Arctic. As sea ice retreats and the extent of open water increases, local particle sources are expected to become more relevant to Arctic aerosol budgets and cloud processes. The results provide observational constraints on particle fluxes and may help to reduce related uncertainties in Arctic aerosol and climate model simulations.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"11 1","pages":"14507-14530"},"PeriodicalIF":6.3,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asymptotic behavior of lidar scattering properties of absorbing dust aerosols across Rayleigh and geometrical-optics regimes: theory and implications","authors":"Anthony La Luna,Zhibo Zhang,Qianqian Song,Hongbin Yu,John E. Yorks,Ping Yang","doi":"10.5194/acp-26-14487-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14487-2026","url":null,"abstract":"Lidar ratio ( S ), linear depolarization ratio ( δ ), and single-scattering albedo ( ω ) are central quantities for dust typing and property retrieval in lidar remote sensing. We investigate their dependence on size parameter ( x ) and iron oxide fraction of mineral dust using TAMUdust2020 and triaxial-ellipsoid calculations. Results show a consistent asymptotic structure that is weakly sensitive to particle shape in both limits of scattering theory. In the Rayleigh limit ( x ≪1), S∝x-3 and ω ∝ x 3 , while δ remains small. In the geometrical-optics limit ( x ≫1), δ decreases toward low values and ω→1/2, whereas S increases because backscatter is reduced relative to extinction by strong absorption and diffraction-dominated scattering. These asymptotic constraints provide a unified physical interpretation of multiwavelength dust-lidar behavior and help explain observed spectral variability of dust depolarization and lidar ratio. A key implication is that large, strongly absorbing dust can produce optical signatures that overlap with weakly depolarizing aerosol classes, which may bias standard classification and inversion schemes toward underestimation of coarse and super-coarse dust contributions.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"1 1","pages":"14487-14506"},"PeriodicalIF":6.3,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Summertime ozone sensitivity to temperature in China: observational evidence and mechanistic attribution in urban and rural areas in the Yangtze River Delta region","authors":"Chang Su,Massimo Bollasina,James Weber,David Stevenson","doi":"10.5194/acp-26-14439-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14439-2026","url":null,"abstract":"As climate change increases frequency and intensity of hot extremes, understanding how elevated temperatures influence surface ozone (O 3 ) across different chemical regimes is critical. We combine observations from summer 2022 in the Yangtze River Delta (YRD) with controlled United Kingdom Chemistry and Aerosols (UKCA) Box experiments for urban Shanghai and a lower-NO x , biogenically influenced Lishui regional environment. Observed daily-maximum O 3 increases with temperature at both sites, with a stronger response in Shanghai. Two-dimensional T -RH distributions show that O 3 rises with temperature and decreases with relative humidity (RH), implying that part of the temperature response is mediated by drying. Factorial box-model experiments separate the roles of temperature-driven shifts in chemical partitioning, diurnal thermal structure, temperature-dependent isoprene emissions, and humidity. In Shanghai, the increase in O 3 between 30 and 40 °C is dominated by BVOC-driven chemistry, with temperature-amplified isoprene emissions explaining most of the observed response. In Lishui, O 3 sensitivity is governed primarily by radical-NO x chemistry and thermal PAN-NO x cycling, with a much smaller role for BVOCs. Fixed RH scenarios substantially reduce the apparent contribution of “thermal chemistry”, highlighting humidity-dependent O x loss and HO x -NO x cycling as key modifiers of the climate penalty. Because the 0-D framework excludes transport and meteorological dynamics, the reported fractions isolate the local chemical and emission-driven component of the O 3 -temperature relationship. Within this scope, the results identify robust regime-specific mechanisms linking heat, humidity, precursor chemistry, and surface O 3 in the YRD and demonstrate the value of observation-constrained box models as a bridge to regional chemistry-climate simulations.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"40 1","pages":"14439-14469"},"PeriodicalIF":6.3,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of irradiance and mixing layer height on the vertical trace matter distribution in the lower planetary boundary layer – drone-based investigation","authors":"Lasse Moormann,Friederike Fachinger,Holger Tost,Frank Drewnick","doi":"10.5194/acp-26-14417-2026","DOIUrl":"https://doi.org/10.5194/acp-26-14417-2026","url":null,"abstract":"Drone-based atmospheric measurements allow time-resolved investigation of stratification in the lower atmosphere of many atmospherically relevant variables. Measuring a variety of variables can be used, e.g., for mixing layer (height, MLH) identification and examination of the representativity of ground-based measurements in the lowermost boundary layer. We present drone-based vertical profiling during two 2.5-week summer field campaigns in rural Germany to investigate the vertical distribution of trace matter and meteorological variables in the lowermost troposphere. Night-time vertical profiling of temperature, humidity, wind speed, and trace substances (CO 2 , O 3 , particle mass and number concentrations) in the lowest 120 m revealed a multiple-layer fine-scale stratification. Trace substances surpassed several traditional meteorological variables in sensitivity for MLH detection. Among all variables, O 3 and potential temperature were the most reliable MLH markers, highlighting combining trace matter and meteorological measurements to understand stratification processes. Using a gradient-based approach for diurnal vertical profiles up to 500 m above ground, we evaluate under which conditions and to which degree ground-based measurements, used world-wide in networks or during individual field campaigns, can be taken as representative for the lowermost mixing layer, and how strong radiative-driven mixing reduces vertical gradients. Location-specific sources and sinks affect the trace matter distribution in the ML much stronger than irradiance. However, homogeneity of aerosol particle concentrations was strongly promoted under high-radiative conditions, even at low MLHs. This suggests distinguishing between high- and low-irradiation conditions in the planetary boundary layer could improve parameterization for vertical mixing and should be considered when evaluating ground-based data.","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"27 1","pages":"14417-14437"},"PeriodicalIF":6.3,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}