Atmospheric Environment最新文献

{"title":"Development of an emission-driven box model to diagnose ozone formation sensitivity","authors":"Xuezhen Xu ,&nbsp;Xiaorui Chen ,&nbsp;Haichao Wang ,&nbsp;Yuanjun Gong ,&nbsp;Keding Lu","doi":"10.1016/j.atmosenv.2025.121124","DOIUrl":"10.1016/j.atmosenv.2025.121124","url":null,"abstract":"<div><div>Surface ozone (O₃) pollution affects air quality, human health, and the ecosystem. Understanding the complex non-linear relationship between ozone formation and its precursors, nitrogen oxides (NO_x), and volatile organic compounds (VOCs) is critical for policymakers to mitigate the pollution. The Empirical Kinetic Modeling Approach (EKMA) based on classical observation-constrained zero-dimension box model provides the sensitivity of ozone production to precursor concentrations instead of emissions. This makes the box-model EKMA hard to apply in a real emission reduction scenario. Here, we developed an alternative box model approach driven by localized emissions, which are derived from the field-observed concentrations. This model approach reproduced the O₃ variations well by capturing the short-term changes of NO_x and AVOCs emissions among different phases of pollution control during the 31st World University Games in Chengdu in 2023. The EKMA analysis based on this model approach showed a different O₃ response to precursor reductions from the concentration-constrained approach, which overestimated the baseline of O₃ concentration. The result from the EKMA analysis demonstrated that the O₃ level was most sensitive to NO_x due to stringent control strategies during the event and rapidly rebounded to almost VOC-limited regime after the event. The effects of VOCs reduction on O₃ control examined by concentration-constrained model approach were less pronounced than those by emission-driven approach due to the lack of consideration of the emission-to-reaction process. Our findings suggest that the emission-driven box model is applicable for developing O₃ control strategy in the local scale.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"348 ","pages":"Article 121124"},"PeriodicalIF":4.2,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508965","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":"PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in urban Beijing during heating season: Hourly variations, sources, and health risks","authors":"Yu Wang ,&nbsp;Zhaojin An ,&nbsp;Youhua Zhao ,&nbsp;Hao Yu ,&nbsp;Dongbin Wang ,&nbsp;Guodong Hou ,&nbsp;Yuke Cui ,&nbsp;Wuyue Luo ,&nbsp;Qianhe Dong ,&nbsp;Pengtuan Hu ,&nbsp;Leicheng Zhao ,&nbsp;Zhiguo Cao ,&nbsp;Xue Li ,&nbsp;Jingkun Jiang","doi":"10.1016/j.atmosenv.2025.121126","DOIUrl":"10.1016/j.atmosenv.2025.121126","url":null,"abstract":"<div><div>Understanding the dynamic variations, potential sources and corresponding health risks of polycyclic aromatic hydrocarbons (PAHs) is essential for developing emission reduction strategies to lower their concentrations and associated health risks. Measurements with 2-h resolution of 16 U.S. Environmental Protection Agency (EPA) priority-controlled PAHs in atmospheric PM_2.5 were carried out at the beginning and midterm of the heating season in urban Beijing during 2020. The measurements utilized an enhanced comprehensive two-dimensional gas chromatography mass spectrometry with aerosol thermal desorption technique. The daily average concentrations of PM_2.5-bound PAHs range from 27.3 to 34.8 ng/m³ in November at the beginning of the heating season, while elevated to 47.9–77.8 ng/m³ in December during the midterm of the heating season. The ratio of PAHs to PM_2.5 during the midterm of the heating season is four times higher than that at the beginning. This increase was due to the rise in concentrations of naphthalene (NaP), fluorene (FLR), and phenanthrene (PHE), along with the decrease in PM_2.5 concentrations in December. The overall diurnal variations exhibit high levels at night and early morning, contrasting with lower levels in the afternoon. However, compared to the beginning of the heating season, the diurnal variations of PAHs during the midterm show more pronounced enhancement and stronger fluctuations. Throughout the observation periods, coal and wood combustion from the local region surrounding Beijing are the primary emission sources of the 16 PAHs, indicating increased combustion emissions in winter due to higher heating demands. High time-resolution measurements captured transient high health risks by 16 PAHs, with the benzo(a)pyrene equivalent concentration (BaP_eq) temporarily exceeded 5 ng/m³, which may result in short-term acute or subacute health effects. This study provides novel understanding on the pollution of PAHs in atmospheric PM_2.5 during the heating season.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"349 ","pages":"Article 121126"},"PeriodicalIF":4.2,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520098","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":"Black carbon and mineral dust in snow and ice pose risks on the Asian water tower","authors":"Hongyu Zhang ,&nbsp;Yulan Zhang ,&nbsp;Sipika Sundriyal ,&nbsp;Tanguang Gao","doi":"10.1016/j.atmosenv.2025.121127","DOIUrl":"10.1016/j.atmosenv.2025.121127","url":null,"abstract":"<div><div>As important light-absorbing impurities, black carbon (BC) and mineral dust (MD) deposited onto glacier and snow surface can substantially alter the response of cryosphere under climate change. As one of the most important cryosphere in the mid-low latitude regions, the Tibetan Plateau and its surroundings (TP, also known as the Third Pole) is considered to be the Asian Water Tower with widespread distributions of snow and glaciers. Based on recent studies, we reviewed the updated research progress of BC and MD from glaciers on the TP and its surroundings, including their concentrations, spatial distributions and potential sources, especially focusing on impacts of BC and MD on glacier melting. The results indicated that there exist large differences of BC and MD spatial distributions due to their different sources or transport pathways. The estimation indicated that BC and MD can enhance the snow and glacier melt by about 20% during ablation season and cause decreasing snow cover duration by 3–4 days. The melting Asian Water Tower are changing the water storage, further influence the water quality and resources to about one billion people in downstream regions. Additionally, we identified research gaps and suggested future research perspectives of BC and MD in snow and ice over the TP and its surroundings.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"349 ","pages":"Article 121127"},"PeriodicalIF":4.2,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534695","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":"Atmospheric chemistry of cyc–CF2CF2CX=CX– (X=H, F): Kinetics, products, and mechanism of gas–phase reactions with OH radicals, and atmospheric implication","authors":"Wenni Zhang,&nbsp;Qin Guo,&nbsp;Hengdao Quan","doi":"10.1016/j.atmosenv.2025.121125","DOIUrl":"10.1016/j.atmosenv.2025.121125","url":null,"abstract":"<div><div>Rate constants for gas-phase reactions of series of hydrofluorocyclobutene including 3,3,4,4-tetrafluorocyclobutene (HFO-c1334zz), 1,3,3,4,4-pentafluorocyclobutene (HFO-c1325yz), and hexafluorocyclobutene (PFO-c1316) with OH radicals were assessed by a relative rate method. The values were determined as (8.47 ± 1.96) × 10⁻¹³ exp[(–475 ± 68)/<em>T</em>], (5.37 ± 0.99) × 10⁻¹³ exp[(–643 ± 53)/<em>T</em>] and (8.41 ± 2.24) × 10⁻¹³ exp[(–905 ± 78)/<em>T</em>] between 253 and 328 K; and 1.77 × 10⁻¹³, 0.644 × 10⁻¹³, and 0.402 × 10⁻¹³ cm³ molecule⁻¹ s⁻¹ at 298K, respectively. The atmospheric lifetimes were 65, 180, and 288 days, while their radiative efficiency (<em>RE</em>) were evaluated to be 0.088, 0.174, and 0.228 W m⁻² ppb⁻¹, respectively. The 100-year time horizon global warming potentials (<em>GWP</em>_<em>100</em>) were estimated to be 6, 31, and 65, respectively. The calculated <em>POCP</em>_<em>E</em> values of HFO-c1334zz, HFO-c1325yz, and PFO-c1316 were then obtained as 1.719 and 0.688 for North-west European and USA urban conditions, 0.579 and 0.222 for North-west European and USA urban conditions, and 0.324 and 0.124 for North-west European and USA urban conditions, respectively. Furthermore, the products and mechanism for the OH radical-initiated oxidation reactions of HFO-c1334zz, HFO-c1325yz, and PFO-c1316 were studied for the first time. COF₂, CO, and CO₂ were identified as the main carbon-containing products of HFO-c1334zz, HFO-c1325yz. Additionally, COF₂, CO₂, CO, and FC(O)OH were observed as the main products of PFO-c1316.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"349 ","pages":"Article 121125"},"PeriodicalIF":4.2,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529239","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":"Development of a multiple solution mixing mechanism based aerosol component retrieval method for polarimetric satellite measurements","authors":"Ying Zhang ,&nbsp;ChaoYu Yan ,&nbsp;Zhengqaing Li ,&nbsp;Haoran Gu ,&nbsp;Yisong Xie","doi":"10.1016/j.atmosenv.2025.121120","DOIUrl":"10.1016/j.atmosenv.2025.121120","url":null,"abstract":"<div><div>Aerosols chemical components from different sources significantly affect climate change and air quality. In this study, we developed a satellite-based aerosol component retrieval method based on multiple solution mixing mechanism (MSMM) to extract global aerosol component from POLDER polarimetric satellite observations from 2008 to 2012. The MSMM calculates the complex refractive index using the Lorentz-Lorenz relation and constrains the solute fraction with κ-Köhler theory to retrieve the following components: black carbon (BC), ammonium nitrate-like inorganic salts (AN), dust (DU), sea salt (SS), water-soluble organic matter (WSOM), water-insoluble organic matter (WIOM), and aerosol water content (AW). By analyzing the spatial distribution and seasonal characteristics of the seven aerosol components over a five-year period, we captured the significant patterns of each aerosol component over global anthropogenic and natural hotspot emission regions. The five-year average and the seasonal patterns of each component during 2008 show significant changes, consistent with our expectations and previous studies. The pattern of global brown carbon (BrC), which is estimated by the possible tracer substances, is correlated with the fire radiative power. After analyzing the time series changes of each component in different regions for five years, we fine that the fine-mode fraction of aerosol component mass concentration in the central-eastern region of China declined about 6.05% from 2008 to 2010, which is closely related to the strong implementation of environmental protection policies. Also, we find the global aerosol component mass fraction in 2012 shows anomalies, especially a significant increase in the AW component, which is explained by the high frequency of extreme weather. The aerosol components retrieved by the MSMM are comparable with MERRA-2, with the correlations up to 0.94 for BC and 0.88 for DU in representative regions. More comprehensive species of aerosol components can be obtained using the MSMM method than MERRA-2, which can be applied to future satellite observations with higher spatial resolution.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"349 ","pages":"Article 121120"},"PeriodicalIF":4.2,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520097","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 profiles of N2O5-related chemical species over Seoul, Korea: Modeling approach and implications for aircraft campaign","authors":"Hyun-Young Jo ,&nbsp;Hyo-Jung Lee ,&nbsp;Gookyoung Heo ,&nbsp;Cheol-Hee Kim","doi":"10.1016/j.atmosenv.2025.121119","DOIUrl":"10.1016/j.atmosenv.2025.121119","url":null,"abstract":"<div><div>Heterogeneous dinitrogen pentoxide (N₂O₅) is an important reactive intermediate in the atmospheric nighttime oxidization of nitrogen oxides and in the formation of nitrate (NO₃⁻) aerosols. However, vertical profiles of N₂O₅-related chemical species over Seoul Metropolitan Area (SMA) are currently lacking. In this study, the Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model was employed and simulated vertical profiles of nighttime N₂O₅-related chemical species to facilitate aircraft-based campaigns over the SMA. The vertical structures of the NO₃ radical (NO₃•) and N₂O₅ were assessed during the meteorologically stagnant period (March 16–17, 2016), which was a typical period of nighttime N₂O₅-driven NO₃⁻ formation in the study region. The results showed that nighttime vertical structures exhibiting higher concentrations of N₂O₅-related chemical species were strongly associated with the nocturnal residual layer (RL), which was decoupled from the ground. Our model showed diminished nighttime NO₃• at the ground but active NO₃• aloft, as it was retained in the RL. We also carried out the same analysis for the stagnant period (May 16–22, 2016) during the KORUS-AQ campaign, and confirmed the similar profiles of high concentration of NO₃• near the altitude of RL. To sum up the cases from this study and KORUS-AQ campaign study, maximum nighttime NO₃• and N₂O₅ concentrations occurred at heights of 78 ± 11% of RL height and 54 ± 15% of RL height, respectively. Although further research on nighttime N₂O₅ chemistry is needed to resolve outstanding uncertainties, the vertical structures of nighttime N₂O₅-related chemical species obtained in this study offer useful reference data for future aircraft campaigns.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"350 ","pages":"Article 121119"},"PeriodicalIF":4.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576869","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":"Analysis of contrasting aerosol indirect effects in liquid water clouds over the northern part of Arabian Sea","authors":"Kashif Anwar ,&nbsp;Khan Alam ,&nbsp;Abdulhaleem H. Labban ,&nbsp;Yangang Liu ,&nbsp;Naila","doi":"10.1016/j.atmosenv.2025.121123","DOIUrl":"10.1016/j.atmosenv.2025.121123","url":null,"abstract":"<div><div>The extensive daily statistics of aerosol properties, cloud properties, and their mutual correlations provide crucial information for better assessing future climate change. In this paper, 14 years (2010–2023) of data from the Moderate Resolution Imaging Spectroradiometer (MODIS) are analyzed over the northern part of Arabian Sea (Latitude: 21°–25° N and Longitude: 62°–68° E) to assess the characteristics of aerosols and clouds and their relationships under different meteorological conditions. When aerosol optical depth (AOD) is less than ∼ 0.7, the observations exhibit a positive correlation between AOD and cloud droplet effective radius (CDR) but negative correlations between AOD and cloud droplet number concentration (CDNC), between AOD and cloud optical depth (COD), between AOD and cloud liquid water path (CLWP), and between AOD and cloud geometrical thickness (H). The corresponding aerosol-cloud correlations change signs when the AOD values are larger than 0.7. However, the single folded positive AOD-cloud fraction (CF) relationship is observed in both AOD regimes. Similar correlations are also observed between precipitable water vapor (PWV) and CDR, CDNC, COD, H, CF and CLWP, together with a positive correlation between PWV and AOD. Further isolation of the environmental effects from aerosol effects by stratifying AOD and cloud data into different LTS and PWV bins shows that the signature of the well-known Twomey effect is observed under high LTS-high PWV conditions, while an opposite effect (anti-Twomey) is observed under low PWV conditions, regardless of LTS values. Additionally, negative correlations between AOD and COD, AOD and CLWP, and AOD and H are observed under low LTS, regardless of PWV conditions, with a slight positive correlation when AOD &gt;0.4 under high LTS and PWV conditions.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"348 ","pages":"Article 121123"},"PeriodicalIF":4.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474527","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":"Dosimetry simulations of ultrafine particles deposition to the human respiratory tract and transport to the olfactory region for female receptors","authors":"Eleftheria Chalvatzaki ,&nbsp;Sofia Eirini Chatoutsidou ,&nbsp;Lila Diapouli ,&nbsp;Maria I. Gini ,&nbsp;Manousos I. Manousakas ,&nbsp;Evangelia Samoli ,&nbsp;Kostas Eleftheriadis ,&nbsp;Mihalis Lazaridis","doi":"10.1016/j.atmosenv.2025.121103","DOIUrl":"10.1016/j.atmosenv.2025.121103","url":null,"abstract":"<div><div>The regional deposited dose of ultrafine particles in the respiratory tract and their transport to the olfactory region was investigated through an existing particle dosimetry model (Exposure Dose Model 2, ExDoM2). The original dosimetry model was adapted to include a methodology that uses numerical modelling for the transport of ultrafine particles from the nose to the olfactory region. The mass dose to the oesophagus, blood, and lymph nodes was also calculated. Four different cases were studied: heating, traffic, nucleation events and background levels. The results showed that deposition in the olfactory region decreased with increasing particle size (from 0.40 % to 0.12 %). The majority of particles were estimated to penetrate into the thoracic region with 36 % of particles within the size range 14–33 nm deposited in the alveolar-interstitial region, followed by the tracheobronchial (21 %), the extrathoracic (11 %) and olfactory (&lt;0.5 %) regions. In addition, a comparison between the mass, surface, and number doses indicated different governing sources such as a higher number dose was obtained during nucleation (10.5 × 10⁸ particles), while higher mass (9.4 × 10⁻² μg) and surface (7.1 × 10¹² nm²) dose was obtained during heating periods. Simulations also indicated that after clearance, 56.9 % of ultrafine particles were found in the alveolar region, a finding that is linked to their small size and low clearance rate of this region. Nevertheless, the dose per unit surface area and the dose per cell in the olfactory region were higher than in the alveolar-interstitial region.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"348 ","pages":"Article 121103"},"PeriodicalIF":4.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic effects of synoptic and quasi-biweekly timescale atmospheric circulation patterns on PM2.5 concentration in South Korea","authors":"Seyeong Lee ,&nbsp;Jeong-Hun Kim ,&nbsp;Maeng-Ki Kim ,&nbsp;Sang-Hyun Lee ,&nbsp;Cheol-Hee Kim","doi":"10.1016/j.atmosenv.2025.121122","DOIUrl":"10.1016/j.atmosenv.2025.121122","url":null,"abstract":"<div><div>In recent years, South Korea has continued to experience high PM_2.5 events despite government efforts, posing a significant threat to human life. This study examines the relationship between high winter PM_2.5 concentrations in South Korea and atmospheric circulation patterns on synoptic and quasi-biweekly timescales. During the winters of 2018–2022, periodicities of 4–8 and 8–26 days were observed in PM_2.5 concentrations, playing a crucial role in high PM_2.5 events. Composite analysis revealed that while atmospheric conditions during high PM_2.5 events shared similar characteristics, their intensity and spatial extent varied. An anticyclonic anomaly was observed in the upper levels over the Korean Peninsula, and the dipole pattern of the mean sea level pressure (MSLP) weakened the Siberian High, reducing northerly winds and weakening the East Asian winter monsoon. Under this atmospheric circulation, both low planetary boundary layer height (PBLH) and stable atmosphere contribute to high PM_2.5 concentrations along with weak ventilation. Anticyclonic anomalies associated with trough intensity originated from different sources: synoptic-scale anomalies from the North Atlantic (∼13 days prior) and quasi-biweekly anomalies from Siberia (∼8 days prior), propagating southeastward as precursor signals. PM_2.5 transport contributions differed by timescale: synoptic events were dominated by transport from eastern China, while quasi-biweekly events showed greater contributions from northern China. When overlapping, these timescales exhibited a synergistic effect, creating more favorable conditions for extreme high-concentration events.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"348 ","pages":"Article 121122"},"PeriodicalIF":4.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Addressing the advantages and limitations of using Aethalometer data to determine the optimal absorption Ångström exponents (AAEs) values for eBC source apportionment","authors":"Marjan Savadkoohi ,&nbsp;Mohamed Gherras ,&nbsp;Olivier Favez ,&nbsp;Jean-Eudes Petit ,&nbsp;Jordi Rovira ,&nbsp;Gang I. Chen ,&nbsp;Marta Via ,&nbsp;Stephen Platt ,&nbsp;Minna Aurela ,&nbsp;Benjamin Chazeau ,&nbsp;Joel F. de Brito ,&nbsp;Véronique Riffault ,&nbsp;Kostas Eleftheriadis ,&nbsp;Harald Flentje ,&nbsp;Martin Gysel-Beer ,&nbsp;Christoph Hueglin ,&nbsp;Martin Rigler ,&nbsp;Asta Gregorič ,&nbsp;Matic Ivančič ,&nbsp;Hannes Keernik ,&nbsp;Marco Pandolfi","doi":"10.1016/j.atmosenv.2025.121121","DOIUrl":"10.1016/j.atmosenv.2025.121121","url":null,"abstract":"<div><div>The apportionment of equivalent black carbon (eBC) to combustion sources from liquid fuels (mainly fossil; eBC_LF) and solid fuels (mainly non-fossil; eBC_SF) is commonly performed using data from Aethalometer instruments (AE approach). This study evaluates the feasibility of using AE data to determine the absorption Ångström exponents (AAEs) for liquid fuels (AAE_LF) and solid fuels (AAE_SF), which are fundamental parameters in the AE approach. AAEs were derived from Aethalometer data as the fit in a logarithmic space of the six absorption coefficients (470–950 nm) versus the corresponding wavelengths. The findings indicate that AAE_LF can be robustly determined as the 1st percentile (PC1) of AAE values from fits with R² &gt; 0.99. This R²-filtering was necessary to remove extremely low and noisy-driven AAE values commonly observed under clean atmospheric conditions (i.e., low absorption coefficients). Conversely, AAE_SF can be obtained from the 99th percentile (PC99) of unfiltered AAE values. To optimize the signal from solid fuel sources, winter data should be used to calculate PC99, whereas summer data should be employed for calculating PC1 to maximize the signal from liquid fuel sources. The derived PC1 (AAE_LF) and PC99 (AAE_SF) values ranged from 0.79 to 1.08, and 1.45 to 1.84, respectively. The AAE_SF values were further compared with those constrained using the signal at mass-to-charge 60 (<em>m/z</em> 60), a tracer for fresh biomass combustion, measured using aerosol chemical speciation monitor (ACSM) and aerosol mass spectrometry (AMS) instruments deployed at 16 sites. Overall, the AAE_SF values obtained from the two methods showed strong agreement, with a coefficient of determination (R²) of 0.78. However, uncertainties in both approaches may vary due to site-specific sources, and in certain environments, such as traffic-dominated sites, neither approach may be fully applicable.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"349 ","pages":"Article 121121"},"PeriodicalIF":4.2,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}