Orals: Wed, 30 Apr | Room F2
The representations of aerosol and aerosol-cloud interactions (ACI) in conventional Earth system models are overly simplified due to computational constraints. These simple process representations limit the models’ predictive power as they contribute to significant errors in various parts of the simulated climate system. To address this challenge, we developed neural networks to replace aerosol and ACI processes (optics, activation, and precipitation) in the U.S. Department of Energy’s Energy Exascale Earth System Model (E3SM). These neural networks are trained on high-fidelity-high-resolution data and achieve remarkably high accuracy in offline tests. When implemented in E3SM, robust tests and guardrails are needed to ensure that the model produces correct and stable simulations and that their computational cost is low enough so that multi-year global simulations are possible. The hybrid E3SM produces a much more accurate characterization of aerosol and ACI, which leads to a very different climate simulation. To evaluate E3SM, an observationally based emulator has also been developed for understanding aerosol’s role in modulating various atmospheric features across scales in the real world. We highlight that the new hybrid approach, combining physics and artificial intelligence, provides ample opportunities for advancing understanding and predictability of the role of aerosols in the Earth system.
How to cite: Ma, P.-L., Geiss, A., Christensen, M., Huang, M., Qin, Y., Singh, B., Pritchard, M., Morrison, H., Silva, S., Rothenberg, D., and Yu, S.: Advancing aerosols in Earth system modeling with artificial intelligence, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4600, https://doi.org/10.5194/egusphere-egu25-4600, 2025.
New particle formation (NPF) is a significant source of atmospheric aerosols. The formation rate (J) quantifies the rate at which new particles form, and can be empirically determined from the particle number size distribution (PNSD). However, identifying the specific causes of NPF in urban areas remains challenging.
It is believed that in urban environments, most NPF occurs through the clustering of sulfuric acid (H2SO4) with bases. However, in a chamber study, it was observed that also the clustering of H2SO4 with highly oxygenated organic molecules (HOMs) may greatly promote NPF (Riccobono, 2014, Science, 344(6185), 717-721).
This research project employs AI data-driven approaches to predict J and examine the role of HOMs in NPF events.
The data were collected in August 2022 in two close sites in Leipzig, Germany: an urban background (Leibniz Institute for Tropospheric Research) and a roadside (Eisenbahnstraße). The data include HOMs, H2SO4, and bases from the nitrate CIMS, PNSD measurements, pollutants such as BC, and meteorological variables. Previous research indicated a higher concentration of OOMs at the roadside (Brean, 2024, Environ. Sci. Technol. 58, 10664−10674), suggesting its potential impact on J.
Preliminary results show that our data-driven model successfully predicted J values on a logarithmic scale with a mean absolute error of 0.33 at the urban background site and 0.63 at the roadside. Further analysis reveals the most significant contributors to predicting J, indicating that alongside H2SO4, various HOMs play a crucial role.
How to cite: Bortolussi, F., Brean, J., Barua, S., Kumar, A., Karppinen, A., Iyer, S., Sandström, H., Shi, Z., Harrison, R., Rinke, P., and Rissanen, M.: Exploring the Role of Highly Oxygenated Organic Molecules in New Particle Formation Events with Explainable Artificial Intelligence, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6788, https://doi.org/10.5194/egusphere-egu25-6788, 2025.
In forested regions around the world, biogenic emissions have been reported to be key drivers of new particle formation (NPF) that contribute to about half the budget of global cloud condensation nuclei (CCN). However, over the central U.S., far from forests and influenced by croplands and urban emissions, the processes driving NPF and CCN are not well understood. Using detailed regional model simulations using WRF-Chem, we show that acid-base reactions including sulfuric acid and dimethyl amines (DMA) are key nucleation drivers at the SGP site during two simulated days in the springtime. We also show that anthropogenic extremely low volatility organics (ELVOCs) formed by the oxidation of anthropogenic VOCs in the atmosphere are critical for explaining the observed particle growth. Conversely, simulated non-NPF days at SGP are characterized by low-level clouds, which reduce photochemical activity, sulfuric acid, and ELVOC concentrations, thereby explaining the lack of NPF. At the Bankhead National Forest (BNF) site the southeastern U.S., we show that nucleation rates are limited by availability of sulfuric acid in this forested area. Our study highlights the large potential heterogeneities in nucleation and particle growth mechanisms between forested and urban/farmland-influenced areas that need to be verified with new BNF measurements.
Additionally, we simulate droplet-resolved cloud chemistry and the interactions between turbulence and cloud chemistry using a one-dimensional explicit mixing parcel model (EMPM-Chem) to simulate how isoprene epoxydiol secondary organic aerosol (IEPOX-SOA) formation evolves in individual cloud droplets within rising cloudy parcels in the atmosphere. We find that as subsaturated air is entrained into and turbulently mixed with the cloud parcel, cloud droplet evaporation causes a reduction in droplet sizes, which leads to corresponding increases in per droplet ionic strength and acidity. Increased droplet acidity in turn greatly accelerates the kinetics of IEPOX-SOA formation. Our results provide key insights into single-cloud-droplet chemistry, suggesting that entrainment mixing may be an important process that increases SOA formation in the real atmosphere.
How to cite: Shrivastava, M., Zhang, J., Zaveri, R., Zhao, B., Pierce, J., O' Donnell, S., Fast, J., Gaudet, B., Shilling, J., Zelenyuk, A., Murphy, B., Pye, H., Zhang, Q., Trousdell, J., Chen, Q., Krueger, S., Shaw, R., and Ovchinnikov, M.: Processes governing new particle formation over croplands and urban influenced central USA and effects of entrainment mixing on cloud chemistry and formation of secondary organic aerosols, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3830, https://doi.org/10.5194/egusphere-egu25-3830, 2025.
Atmospheric new particle formation (NPF) is an extremely complex chemical process that produces aerosols directly from gas phase species, impacting air quality, human health, and climate. Observations have shown frequent NPF in polluted urban areas even with high preexisting aerosols, but it is unclear how low-volatility oxygenated organics contribute to urban aerosol nucleation. Urban NPF studies in Chinese megacities show that urban nucleation takes place from sulfuric acid and dimethylamine, yet the measured aerosol nucleation rates cannot be explained with sulfuric acid and dimethylamine alone. There are abundant oxygenated organic molecules (OOM) in Chinese megacities, but these OOMs primarily form from oxidation reactions of aromatic compounds and the majority of OOMs contain nitrates and the volatilities of OOMs are not sufficiently low enough to be able to nucleate. To understand the role of low-volatility OOMs in urban aerosol nucleation, we conducted comprehensive measurements of NPF precursors in Houston, the 4th most populated and polluted urban site in the United States. Our observations, together with numerical parameterizations constrained by the in-situ measured chemical precursors and based on the algorithms provided by the chamber experiments, show that rapid nucleation and growth of freshly formed clusters can be explained by the measured sulfuric acid, base, and low-volatility OOMs (with saturation vapor concentrations in the low or extremely volatility ranges). The chemical composition analysis of OOMs, together with F0AM box model simulations incorporated with the Master Chemical Mechanism, show that under the urban Houston conditions, OOMs form oxidation from both biogenic and anthropogenic VOCs, and autoxidation and dimerization of organic peroxides are not suppressed by NOx. Our findings thus contrast with previous urban studies mostly made in Chinese megacities, demonstrating the distinctively different roles of organics in urban aerosol nucleation under different urban settings due to different emission profiles and chemical compositions of air pollutants. Given rapid global urbanization and increasing emissions of emerging chemical pollutants in the United States and Europe, this multicomponent nucleation process will be crucial for mitigating air pollution in the evolving urban climate.
How to cite: Lee, S.-H., Tiszenkel, L., Flynn, J., and Dodero, A.: Role of Low-Volatility Oxygenated Organic Molecules in Urban Aerosol Nucleation in Houston, Texas , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12803, https://doi.org/10.5194/egusphere-egu25-12803, 2025.
The aerosol chemical mixing state refers to the distribution of chemical components within individual aerosol particles, which affects their physical properties and interactions with the environment, such as light absorption, cloud formation, and potential health impacts. Accurate estimations of aerosol chemical mixing states are crucial for assessing both climate and health impacts. While particle-resolved models can track changes in aerosol compositions, they often struggle to capture real-world mixing states due to limitations in input data quality, such as emission inventories used in simulations.
In this study, we developed a deep learning foundation model based on particle-resolved simulations and fine-tuned it with limited observational data. The process-guided fine-tuned model improved R² by 300% compared to a fully data-driven baseline, effectively mitigating the challenges posed by sparse observational data and uncertainties model simulations.
Our approach enables dynamic estimations of aerosol mixing states in real-world environments, offering scalability and continuous learning.
How to cite: Jiang, F., Zheng, Z., Coe, H., Topping, D., Riemer, N., and West, M.: Integrating Simulations and Observations: A Foundation Model for Estimating Aerosol Mixing State Index, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6321, https://doi.org/10.5194/egusphere-egu25-6321, 2025.
Atmospheric soot and organic particles from fossil fuel combustion and biomass burning modify Earth’s climate through their interactions with solar radiation and through modifications of cloud properties by acting as cloud condensation nuclei and ice nucleating particles. Recent advancements in understanding their individual properties and microscopic composition have led to heightened interest in their microphysical properties. This review article provides an overview of current advanced microscopic measurements and offers insights into future avenues for studying microphysical properties of these particles. To quantify soot morphology and ageing, fractal dimension (Df) is a commonly employed quantitative metric which allows to characterize morphologies of soot aggregates and their modifications in relation to ageing factors like internal mixing state, core-shell structures, phase, and composition heterogeneity. Models have been developed to incorporate Dfand mixing diversity metrics of aged soot particles, enabling quantitative assessment of their optical absorption and radiative forcing effects. The microphysical properties of soot and organic particles are complex and they are influenced by particle sources, ageing process, and meteorological conditions. Furthermore, soluble organic particles exhibit diverse forms and can engage in liquid-liquid phase separation with sulfate and nitrate components. Primary carbonaceous particles such as tar balls and soot warrant further attention due to their strong light absorbing properties, presence of toxic organic constituents, and small size, which can impact human health. Future research needs include both atmospheric measurements and modeling approaches, focusing on changes in the mixing structures of soot and organic particle ensembles, their effects on climate dynamics and human health.
How to cite: Li, W.: Microphysical Properties of Atmospheric Soot and Organic Particles: Measurements, Modeling, and Impacts, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14445, https://doi.org/10.5194/egusphere-egu25-14445, 2025.
Black carbon (BC) aerosol particles are emitted by the incomplete combustion of carbonaceous fuels. These particles absorb solar radiation and BC-dominated aerosol mixtures with low single scattering albedo have a positive radiative forcing, thus heating the atmosphere. Radiative transfer models make use of the BC mass absorption cross section (MACBC) to derive the radiative forcing of BC given a certain particle mass concentration. Freshly emitted BC has a MAC value of 8 ± 1 m2/g at 550 nm (Bond et al., 2013). However, MAC can increase as aerosols age in the atmosphere due to increase in particle coating. This is the so-called lensing effect, which leads to MACBC observations of up to 15 m2/g at 550 nm (Li et al., 2022; Savadkoohi et al., 2024). The effect of coatings and the evolution of MACBC with ageing have been and still are a matter of intense scientific discussions.
The determination of MACBC is carried out in the lab and in the field using various methods for light absorption and BC mass measurement. The most common techniques for absorption measurement include filter-based attenuation measurements, whereas the most common technique for mass measurement is thermo-optical analysis, which quantifies elemental carbon mass (EC; EN 16909:2017). The development of more accurate techniques with operational and scientific advantages for both light absorption and BC mass quantification has led to more reliable MACBC field measurements, allowing researchers to have a clearer picture of how atmospheric ageing and regional conditions affect the optical properties of BC.
In this study, we have reviewed 63 publications that provide atmospheric MACBC values and present the results in terms of aerosol type, measurement technique, regional variability, and how interpretation of results using these factors can help the community to use the appropriate MAC in models. We provide guidance and perspectives for future studies and how the literature on MACBC can be exploited and interpreted in order to improve radiative models that include BC.
References
Bond, T. C., Doherty, S. J., Fahey, D. W., Forster, P. M., Berntsen, T., DeAngelo, B. J., Flanner, M. G., Ghan, S., Kärcher, B., Koch, D., Kinne, S., Kondo, Y., Quinn, P. K., Sarofim, M. C., Schultz, M. G., Schulz, M., Venkataraman, C., Zhang, H., Zhang, S., … Zender, C. S. (2013). Bounding the role of black carbon in the climate system: A scientific assessment. Journal of Geophysical Research: Atmospheres, 118(11), 5380–5552. https://doi.org/10.1002/jgrd.50171
Hanyang Li & Andrew A. May (2022) Estimating mass-absorption cross-section of ambient black carbon aerosols: Theoretical, empirical, and machine learning models, Aerosol Science and Technology, 56:11, 980-997, https://doi.org/10.1080/02786826.2022.2114311
Savadkoohi, Marjan, Marco Pandolfi, Cristina Reche, Jarkko V. Niemi, Dennis Mooibroek, Gloria Titos, David C. Green, et al. (2023) The Variability of Mass Concentrations and Source Apportionment Analysis of Equivalent Black Carbon across Urban Europe. Environment International 178: 108081. https://doi.org/10.1016/j.envint.2023.108081.
How to cite: Saturno, J., Corbin, J. C., Backman, J., Vasilatou, K., Weingartner, E., Ciupek, K., Müller, T., Arun, B. S., Močnik, G., Drinovec, L., Eleftheriadis, K., and Asmi, E.: Atmospheric black carbon mass absorption cross-section: a literature review, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17364, https://doi.org/10.5194/egusphere-egu25-17364, 2025.
Black Carbon (BC) aerosol is a major short-lived climate forcer which plays a significant role in both atmospheric warming and air quality. BC is emitted during incomplete combustion during fossil fuel combustion, biomass burning and domestic heating but its emission fluxes estimate remains uncertain. The accurate representation of BC fluxes and its atmospheric fate in climate models is crucial for understanding BC contribution to climate change. This study aims to optimize the total BC emissions, using as starting point the emission inventories provided by CMIP6 for both anthropogenic and biomass burning sources. For this, a data assimilation global 3-d modeling system was used together with filter and aethalometer measurements of BC worldwide. The assimilation system used is the forward chemistry and transport model TM5-MP combined with the Carbon Tracker Data Assimilation Shell (CTDAS) that utilizes an Ensemble Kalman filter data assimilation method. The TM5-MP model simulates atmospheric chemistry and aerosol microphysics using the M7 module in the global atmosphere driven by ERA-5 meteorology and running with a 2ox3o horizontal resolution and 25 hybrid levels up to 0.1 hPa. The efficiency of the optimisation method is evaluated by comparing the forward simulations with the aerosol optical depth observations from the AERONET network before and after the emission optimization.
How to cite: Gkouvousis, A., Gialesakis, N., Drosos, A., Maris, I., and Kanakidou, M.: Global inversions of black carbon emissions using TM5-MP coupled with CTDAS, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19589, https://doi.org/10.5194/egusphere-egu25-19589, 2025.
The Northern Hemisphere boreal region is undergoing rapid warming, leading to an upsurge in biomass burning. Previous studies have primarily focused on greenhouse gas emissions from these fires, whereas the associated biomass burning aerosols (BBAs) have received less attention. Here we use satellite-constrained modelling to assess the radiative effect of aerosols from boreal fires on the climate in the Arctic region. We find a substantial increase in boreal BBA emissions associated with warming over the past two decades, causing pronounced positive radiative effects during Arctic summer mostly due to increased solar absorption. At a global warming level of 1 °C above current temperatures, boreal BBA emissions are projected to increase 6-fold, further warming the Arctic and potentially negating the benefits of ambitious anthropogenic black carbon mitigation. Given the high sensitivity of boreal and Arctic fires to climate change, our results underscore the increasingly relevant role of BBAs in Arctic climate.
How to cite: Zhong, Q., Schutgens, N., Veraverbeke, S., van der Werf, G., and Tao, S.: Increasing aerosol emissions from boreal biomass burning exacerbate Arctic warming, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5023, https://doi.org/10.5194/egusphere-egu25-5023, 2025.
Aerosol acidity (or pH) is one central parameter in determining the health, climate and ecological effects of aerosols. While it is traditionally assumed that the long-term aerosol pH levels are determined by the relative abundances of atmospheric alkaline to acidic substances (referred to as RC/A hereinafter), we observed contrasting pH - RC/A trends at different sites globally, i.e., rising alkali-to-acid ratios in the atmosphere may unexpectedly lead to increased aerosol acidity. Here, we examined this apparently counter-intuitive phenomenon using the multiphase buffer theory. We show that the aerosol water content (AWC) set a pH “baseline” as the peak buffer pH, while the RC/A and particle-phase chemical compositions determine the deviation of pH from this baseline within the buffer ranges. Therefore, contrasting long-term pH trends may emerge when RC/A increases while AWC or nitrate fraction decreases, or vice versa. Our results provided a theoretical framework for a quantitatively understanding the response of aerosol pH to variations in SO2, NOx versus NH3 and dust emissions, offering broad applications in studies on aerosol pH and the associated environmental and health effects.
How to cite: Zheng, G., Su, H., Wan, R., Duan, X., and Cheng, Y.: Rising alkali-to-acid ratios in the atmosphere may correspond to increased aerosol acidity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11298, https://doi.org/10.5194/egusphere-egu25-11298, 2025.
Atmospheric acidity is a major aerosol parameter that influences atmospheric chemistry, nutrient availability and deposition rates, aerosol formation and growth rates, nutrient availability, aerosol toxicity and the ability of aerosol to nucleate ice crystals and cloud droplets. Aerosol acidity depends on the concentration and volatility of precursor gases/bases, the amount of non-volatile cations (such as Ca, K, Mg), sulfate, temperature and humidity. Understanding how aerosol acidity changes between airmasses and its vertical evolution from moist, warm boundary layer conditions (close to source regions), into the dry, cold and clean free tropospheric air is highly unconstrained from observations. High altitude mountaintop sites observations offer a unique opportunity to address this uncertainty, as observations required to constrain aerosol pH can be carried out for extensive periods of time, and can sample both free tropospheric and boundary layer air from a variety of sources and over different seasons.
This study addresses the need for vertical profiling of aerosol pH by utilizing the extensive dataset available from the CleanCloud CHOPIN field campaign (https://go.epfl.ch/chopin-campaign) at Mount Helmos, Greece from Fall 2024 to Spring 2025. pH is calculated with the ISORROPIA-Lite thermodynamic model applied to the aerosol chemical composition and gas-phase NH3 measurements carried out at the Helmos Hellenic Atmospheric Aerosol and Climate Change ((HAC)²) station (2314 m a.s.l.) at mount Helmos. Airmass origin is identified through a series of chemical and turbulence metrics (to identify when observations correspond to boundary layer or free tropospheric conditions) and backtrajectory analysis when the site is residing in the free troposphere. We observed a clear daily pH cycle at the site, with lower pH values between 7 am and 1 pm, where the airmass is predominantly influenced by free tropospheric air. Higher pH values tend to be observed in the afternoon when ammonia associated with anthropogenic emissions from nearby urban and agricultural activities reached the station, which together with higher humidity and ammonia levels end up reducing acidity. Seasonal variations and the influences of dust episodes, biomass burning and temperature are all analyzed to determine "characteristic" acidity levels associated with each airmass type and infleunce. We then conclude by discussing the implications of the acidity levels for nutrient availability and deposition in each regime, and discuss the ability of models to reproduce the observed acidity patterns.
How to cite: Nenes, A., Molina, C., Foskinis, R., Zografou, O., Gini, M., Granakis, K., Fetfatzis, P., Mitsios, C., Papayannis, A., and Eleftheriadis, K.: Multiseasonal aerosol pH variations between boundary layer and free tropospheric airmasses in the East Mediterranian during the CleanCloud CHOPIN Campaign, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19876, https://doi.org/10.5194/egusphere-egu25-19876, 2025.
Semi-volatile compounds (organics, nitrate, chloride, ammonium) are ubiquitous in atmospheric aerosols and usually contribute over 50% to the fine aerosol mass worldwide. Their gas precursors (organics, HNO3, HCl, NH3) can co-condense with water vapour as an extra source of aerosol particle growth when ambient relative humidity (RH) increases, therefore facilitating hygroscopic growth under sub-saturated conditions and activation to cloud condensation nuclei (CCN). Yet, the attribution of co-condensing semi-volatile compounds to the CCN activation is poorly understood.
Topping et al. (2013) developed a cloud parcel model to simulate the co-condensation effect of organics and sensitivities to key influencing factors (e.g. aerosol concentration, updraft velocity) for the first time. Building on Topping’s study, we further developed a cloud parcel model that simulates co-condensation for both organic and inorganic compounds. We used in-situ observations of gas and aerosols from SMEAR II Hyytiälä Forestry Field Station in Finland as input and quantified co-condensation for inorganics, organics, and their combination. Evaporation losses of particulate semi-volatile compounds in the sampling and non-ideality of organics are also considered.
In Hyytiälä, the inclusion of co-condensing semi-volatile compounds to CCN activation is sensitive to the updraft velocity (0.003 – 5 m s-1) and assumed volatility distribution and non-ideality of organics. The volatility distribution of organics is highly uncertain but important because it relates the amount of organic gas precursors with measured mass concentration in the condensed phase. Topping et al. (2013) simulated co-condensation of organic compounds with volatility bins up to C* = 10-3 μg m-3, saturation mass concentration of organics in condensed phase. To understand the role of more volatile bin C* = 10-4 μg m-3 which is usually considered too volatile for co-condensation, we modified volatility basis set of Topping et al (2013) by adding an extra bin C* = 10-4 μg m-3. We found that the bin C* = 10-4 μg m-3 can play a large role in CCN activation when temperature decreases, resulting in a 30% higher cloud droplet number concentration (CDNC), consistent with Heikkinen et al. (2024). For the combined co-condensation of organics and inorganics increase CDNC by up to 52% with bin C* = 10-4 μg m-3 compared to 40% without the bin. The semi-volatile compounds evaporated by ~10% due sampling losses, dryer tubes, and outdoor-indoor temperature changes before detection by the instrument, which should be considered in the total organic mass estimate. Non-ideality of the system is important for considering the co-condensation effect realistically. Assuming ideality, co-condensation is overestimated by 100% in CDNC. The combined enhancement in CDNC of inorganic and organic species goes beyond the sum of individual effects and should be further constrained and properly estimated in models.
Reference:
Heikkinen et al. (2024), Cloud response to co-condensation of water and organic vapors over the boreal forest, Atmos. Chem. Phys., 24(8), 5117-5147.
Topping, D., P. Connolly, and G. McFiggans (2013), Cloud droplet number enhanced by co-condensation of organic vapours, Nature Geoscience, 6, 443.
How to cite: Wang, Y., Kleinheins, J., Luo, B., Marcolli, C., Peter, T., Chen, Y., Chen, G., and Lohmann, U.: Sensitivity studies on cloud droplet number enhancement from the co-condensing NH3, HNO3, and organic vapours in Hyytiälä, Finland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1326, https://doi.org/10.5194/egusphere-egu25-1326, 2025.
The microphysical properties of natural and anthropogenic aerosols play a crucial role in cloud formation, particularly in water uptake and droplet activation. Köhler's theory provides a framework for predicting the critical supersaturation at which a droplet activates, combining the effects of solute-induced water vapour reduction and surface curvature. While effective for inorganic compounds, the theory inaccurately predicts water uptake in droplets containing organic species. Models incorporating surfactant effects offer potential improvements but require robust experimental data for validation. At the same time, conventional ensemble measurements average over droplet size and compositional heterogeneities, obscuring critical single-particle behaviours.
To address these limitations, we present a dual-beam optical trap for studying droplet activation in single aerosol particles. The setup uses counter-propagating laser beams to stably trap individual particles, enabling precise size and refractive index measurements via Cavity-Enhanced Raman Spectroscopy. A specially designed cell, featuring cooling and heating sections, establishes controlled temperature and relative humidity/supersaturation gradients, enabling the investigation of droplet growth under defined conditions. Additionally, the setup is equipped with a high-speed camera to monitor the activation and subsequent growth of droplets, allowing real-time visualization of growth dynamics. By systematically isolating individual particles and monitoring their behaviour, this technique avoids the averaging effects inherent to ensemble methods, providing high-resolution data critical for validating and refining models of organic aerosol activation.
How to cite: Odelskii, A., Malashevych, S., Logozzo, A., and Preston, T.: Development of a Dual-Beam Optical Trap for Monitoring Water Uptake and Activation of Single Aerosol Particles, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2187, https://doi.org/10.5194/egusphere-egu25-2187, 2025.
Atmospheric aerosol hygroscopicity and reactivity play key roles in determining the aerosol’s fate and are strongly affected by its composition and physical properties. Fatty acids are surfactants commonly found in organic aerosol emissions. They form a wide range of different nanostructures dependent on water content and mixture composition. We follow nano-structural changes in mixtures frequently found in urban organic aerosol emissions, i.e. linoleic acid (LOA), oleic acid (OA), sodium oleate and fructose, during humidity change and exposure to the atmospheric oxidant ozone. Small-Angle X-ray Scattering (SAXS) was employed (Milsom et al., 2024) to derive the hygroscopicity of each nanostructure by measuring time- and humidity-resolved changes in nano-structural parameters. We found that hygroscopicity is directly linked to the specific nanostructure. Reaction with ozone revealed a clear nanostructure-reactivity trend, with notable differences between the individual nanostructures investigated. Simultaneous Raman microscopy complementing the SAXS studies revealed the persistence of oleic acid even after extensive oxidation. Our findings demonstrate that self-assembly of fatty acid nanostructures can significantly impact water uptake and chemical reactivity, thus directly affecting the atmospheric lifetime of these materials.
Another focus of our studies are one-molecule thin layers of LOA and their behaviours when exposed to ozone in multi-component films at the air–water interface (Woden et al., 2024). LOA’s two double bonds allow for ozone-initiated autoxidation, a radical self-oxidation process, as well as traditional ozonolysis. Neutron reflectometry was employed to follow the kinetics of these films in real time in a temperature-controlled environment. We oxidised deuterated LOA (d-LOA) as a monolayer, and in mixed two-component films with either oleic acid (h-OA) or its methyl ester, methyl oleate (h-MO), at room temperature and atmospherically more realistic temperatures of 3 ± 1 °C. We found that the temperature change did not notably affect the reaction rate which was similar to that of pure OA. Kinetic multi-layer modelling using our Multilayer-Py package showed that neither temperature change nor introduction of co-deposited film components alongside d-LOA consistently affected oxidation rates, but the deviation from a single process decay behaviour (indicative of autoxidation) at 98 ppb is clearest for pure d-LOA, weaker for h-MO mixtures and weakest for h-OA mixtures. As atmospheric surfactants will be present in complex, multi-component mixtures, it is important to understand the reasons for these different behaviours even in two-component mixtures of closely related species. Our work demonstrates that it is essential to employ atmospherically realistic ozone levels as well as multi-component mixtures to understand LOA behaviour at low O3 in the atmosphere. Residue formation may be affected by the temperature change, potentially impacting on the persistence of the organic character at the surface of aqueous droplets. Our findings could have impacts on both urban air quality (e.g. protecting harmful urban emissions from atmospheric degradation and therefore enabling their long-range transport), and climate (e.g. affecting cloud formation), with implications for human health and wellbeing.
Milsom et al., Atmos. Chem. Phys., 2024, 24, 13571–13586, DOI: 10.5194/acp-24-13571-2024, 2024.
Woden et al., Faraday Discuss., 2024, DOI: 10.1039/D4FD00167B.
How to cite: Pfrang, C., Milsom, A., Woden, B., Skoda, M., Su, Y., Ward, A., Smith, A., Squires, A., and Laurence, B.: Impact of nanostructure on hygroscopicity and reactivity of fatty acid atmospheric aerosol proxies., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18595, https://doi.org/10.5194/egusphere-egu25-18595, 2025.
Aerosols significantly influence air quality, climate, and health. Specifically, aerosols can influence climate directly though scattering/absorbing and indirectly in their capacity of cloud condensation nuclei. Aerosols exist in the atmosphere in different morphologies (e.g. core-shell) which can as a result can affect their scattering properties. This study explores the Mie scattering of an organically coated mineral aerosol when exposed to an atmospherically significant oxidant: Hydroxyl radical, OH∙.
Figure 1. Laser tweezer trap with annotated optical pathway.
Atmospheric oxidation by OH∙ can cause changes to an organic particle’s optical properties. Utilising a combination of Optical Tweezers and Mie Spectroscopy (figure 1) the significance of exposure to OH∙ has on both homogenous and coated aerosols can be studied. These techniques were used since they enable the manipulation and analysis of individual aerosol particles (~1 µm radii) in a controlled environment. OH∙ was generated in situ, due to its short lifetime, through the mechanism outlined in equation 1.
(eq.1)
From Mie theory we know that the movement of Mie resonance peaks indicate a change in the optical properties of the levitated particle. Said changes can be attributed to loss of organic material and/or shift in refractive index (indicating a chemical change in the organic sample).
Figure 2. Line graph illustrating the movement of a single peak from the recorded Mie spectra (peak shift) over time whilst the optically levitated particle is exposed to OH∙.
Results are measured in terms of the shifting of Mie resonance peaks and show that real urban atmospheric coatings react with OH∙, and that reaction is to a significant scale (-1.23 nm / 60 minutes) as seen in figure 2. Woodsmoke yielded no significant reaction (figure 2). Squalane thin films reacted significantly, presenting a peak shift of -5.73 nm / 60 minutes and was repeatable (figure 2). The homogenous squalane droplets also showed significant change. Overall, it has been determined that for the squalane and real urban organic samples form a core-shell morphology with silica. Furthermore, these thin films present a negative shift in peak position indicating a significant loss of material when exposed to OH∙. Therefore, it can be concluded that OH∙ results in alteration of the optical properties of organic thin films, and this observable behaviour can be considered to an order of magnitude that should be accounted for in atmospheric radiative forcing calculations, however future work is required to model this with detail.
This work was supported by the Natural Environment Research Council and the ARIES Doctoral Training Partnership [grant number NE/S007334/1], NERC grant NE/T00732X/1, with additional support from STFC's Central Laser Facility for access at the Research Complex at Harwell.
How to cite: Poole, M., Ward, A., and King, M.: Investigating Organic-Mineral Core-Shell Aerosols: A Study of Hydroxyl Radical Oxidation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19425, https://doi.org/10.5194/egusphere-egu25-19425, 2025.
The significance of Aerosol-photolysis interaction (API) in photochemistry has been emphasized by studies utilizing box models and chemical transport models. Some of them noted that API is closely related to aerosol vertical distributions. However, few studies have considered the actual aerosol vertical distribution when evaluating API due to the lack of observations and the substantial uncertainties in simulation. Herein, we used lidar and radiosonde observations with the GEOS-Chem model to quantify the response of photochemistry to observational constraints on aerosol vertical distribution across different seasons in North China. The underestimation of aerosol optical depth (AOD) in lower layers and the overestimation in upper layers were revised. Vertically, photolysis rates changed following AOD, showing 33.4%–73.8% increases at the surface. Ozone increased by an average of 0.9 ppb and 0.5 ppb in winter and summer and the default API impact on ozone reduced by 36%–56%. The weaker response in summer can be related to the compensatory effects of stronger turbulence mixing in the boundary layer. Besides, the underestimation of ozone levels in winter was improved by 8.5%. PM2.5 increased by 0.8 µg m−3 in winter and 0.2 µg m−3 in summer due to the promotion of photochemistry and increased more during pollution, with a maximum daily change of 16.5 µg m−3 at Beijing station in winter. The weakened API enhanced nitric acid (HNO3) formation by increasing the atmospheric oxidizing capacity (13.7% for OH radical) in high NOx emission areas and this helps explain the strong response of PM2.5in winter.
How to cite: Chen, X., Li, K., Yang, T., Jin, X., Chen, L., Yang, Y., Zhao, S., Hu, B., Zhu, B., Wang, Z., and Liao, H.: Simulated photochemical response to observational constraints on aerosol vertical distribution over North China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6156, https://doi.org/10.5194/egusphere-egu25-6156, 2025.
The behavior and toxicity of particulate matter (PM) is primarily influenced by particle size and chemical composition, with fine (PM2.5) and ultrafine particles (PM0.1) posing the greatest health risks due to their deep respiratory penetration ability and enhanced adsorption capacity. While most studies focus on a single pollutant type – either organic or inorganic − using high-volume air samplers positioned far from areas commonly used by local commuters (e.g. rooftops), data on the multi-pollutant chemical composition of nanoparticles (PM1 or smaller) and their impacts on active commuters in urban environments remains scarce. A ground-level sampling device utilising a low-volume cascade system was employed to collect and fractionate PM-bound metal(oid)s and polycyclic aromatic hydrocarbons (PAHs), including in nanoparticles, over the course of one year in five urban areas across Slovenia, Europe. In the collected samples, metal(oid)s and PAHs were determined by inductively coupled plasma mass spectrometry following microwave-assisted acid digestion, and gas chromatography mass spectrometry after solvent extraction with mechanical shaking. The highest concentrations of metal(oid)s were predominantly found in PM10 (As, Cr, Ni, Pb) and PM<0.1 (Cd, Pd, Pt, Sb) fraction. High-molecular weight PAHs (BaA, BaP, BbF, BghiP, Ch, IP) were more abundant in PM10, while low-molecular weight PAHs (Fl, Na, Pa, P) were more prevalent in finer fractions. The highest concentrations of pollutants across all fractions and locations were consistently observed during the winter months. The contaminants investigated primarily originated from anthropogenic activities, particularly those associated with traffic emissions and biomass burning. Given that pollutants bound to the smallest airborne particles are the most harmful, it is essential to enhance pollution control measures and risk assessment strategies by addressing various PM fractions, including nano-sized particles.
How to cite: Ilenič, A., Đurić, M., Milačič Ščančar, R., Mauko Pranjić, A., and Ščančar, J.: Size-fractionation of airborne particulate matter: chemical properties, distribution and health risk assessment – a one year study in Slovenia, Central Europe, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6515, https://doi.org/10.5194/egusphere-egu25-6515, 2025.
In recent years, the importance of ultrafine particle (UFP) measurements has increased significantly, particularly due to their adverse health effects. For this reason, it is important to further investigate and characterise strong UFP sources, especially in densely populated urban and suburban areas, to shed more light on their impact on local air quality. Former studies have already shown that highly frequented airports are a major source of UFPs (Hudda et al. 2014, Keuken et al. 2015); these studies further showed that even over long distances of up to 10 km downwind of the airport, UFP concentrations are significantly elevated. In this study, we deployed a variety of instruments to characterise the UFPs from Frankfurt Airport (FRA) in the densely populated Rhein-Main area. Size and concentration levels over a size range from 2-800 nm were measured at three different locations which are located 4, 8, and 15 km away from the airport, respectively. Overall, the measurements were conducted over a duration of 6 months. As a result, we found that aerosol emissions from the airport dominate the aerosol population of the neighbouring districts (up to a distance of at least 15 km) to a great extent. This can be seen when comparing particle number concentrations downwind of the airport versus urban background levels. The average diurnal particle number concentration at the closest measurement station with a distance of 4 km from the airport is elevated by almost a factor of 6 during the airport operating hours (05:00 – 23:00) compared to the urban background when the wind is arriving from the airport. Additionally, we found that the particle number concentration of diameters above 3 nm is up to a factor of 5 to 6 higher than the fraction above 10 nm, indicating that a large fraction of aircraft aerosol emissions is below 10 nm in size and therefore remains mostly undetected by standardised UFP measurements. This suggests that the particle burden can be significantly underestimated when only focussing on particles larger than 10 nm. In the presentation a detailed analysis of the measured results at the three different stations will be presented. The analysis focuses on the dependence of the diurnal pattern of the aerosol size distribution as a function of the origin of the air masses (wind direction). This way, airport emissions can be distinguished from other traffic emissions and the urban background. Furthermore, we present direct evidence that landing airplanes can contribute significantly to the smallest measurable particles < 10 nm. Overall, we conclude that for a full assessment of the negative health effects of UFP emissions it is important to (1) increase the number of monitoring stations, especially in areas with strong sources such as airports and (2) lower the size of the smallest particles that are detected from 10 to 3 nm, in order to determine the UFP concentrations and health risks more realistically.
How to cite: Granzin, M., Große Schute, L., Rose, D., Ditas, F., Curtius, J., and Kürten, A.: Measurement of ultrafine Particles (2 to 800 nm) in the Rhein-Main area with a special Emphasis on Airport Emissions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17482, https://doi.org/10.5194/egusphere-egu25-17482, 2025.
Landfills emit a variety of pollutants in both gaseous and liquid phases during the final disposal of waste. Among the gaseous pollutants, hydrogen sulfide (H2S), primarily generated during anaerobic decomposition, oxidizes in the atmosphere to form sulfur oxides (SOx) and contributes as a precursor to particulate matter (PM2.5) formation. While hydrogen sulfide (H2S) can affect local air quality during its atmospheric transport and oxidation, there is a lack of research on the quantitative evaluation of the atmospheric movement and oxidation processes of hydrogen sulfide (H2S) emitted from landfills.
Thus, this study aims to predict the emission of hydrogen sulfide (H2S) through elemental analysis of landfill waste, calculate the conversion to sulfur oxides (SOx), and then assess the impact on local air quality by modeling the diffusion of sulfur oxides (SOx) using the Gaussian plume model.
The sulfur (S) content in waste samples was measured using an elemental analyzer (vario-MARCO), and the potential for hydrogen sulfide (H2S) generation was calculated based on these measurements. Using chemical formulas, the amount of sulfur converted into sulfur oxides (SOx) was estimated. The horizontal and vertical diffusion coefficients (σy, σz) of the converted sulfur oxides (SOx) were determined using the Pasquill-Gifford empirical formula. The diffusion of sulfur oxides (SOx) was then modeled using the Gaussian plume model in Python, up to a distance of 1 km from the emission source.
By utilizing the Gaussian plume model, this study evaluates the conversion and diffusion of hydrogen sulfide from landfills into sulfur oxides and their impact on local air quality. The findings can provide a basis for landfill emission management and the formulation of air pollution reduction policies. Future research should verify the accuracy of the model by comparing the results with real-time air concentration data.
Acknowledgment
"This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute(KEITI) funded by the Ministry of Environment(MOE)"
How to cite: Park, M., Park, H., Lee, N., Jung, M., and Yun, H.-Y.: Atmospheric Dispersion Assessment of Fine Particulate Matter Precursors from Landfills Using the Gaussian Plume Model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3447, https://doi.org/10.5194/egusphere-egu25-3447, 2025.
Cement is an essential material for construction, but cement manufacturing factories are concentrated in areas where the raw materials are produced and the manufacturing process requires a large amount of energy. In Republic of Korea, a total of 50,237 tonnes in 2023 are produced at 13 manufacturing plants composed of 9 cement companies. Among these 13 plants, 6 are located in Gangwon-do Province. The cement production process generates a large amount of pollutants, including nitrogen oxides, sulfur oxides, and fine dust, causing various environmental issues and complaints from local residents in the surrounding areas near by the cement manufacturing factories.
In Republic of Korea, the proportion of using waste materials (especially plastic waste) as an alternative fuel instead of anthracite coal has been increasing recently. Additionally, the nitrogen oxide emission limit for cement manufacturing plants is set at 270 ppm (for facilities installed before 2007), which is much alleviated level than the 70 ppm limit for waste incineration plants (with a capacity of 2 tonnes per hour or more).
Nitrogen oxides emitted into the atmosphere can act as precursor substances for acid rain, and they can also convert into fine dust (<PM 2.5) through photochemical reactions, potentially affecting the concentration of fine particulate matter in the air. The high concentrations of nitrogen oxides emitted from cement manufacturing facilities can impact the fine dust concentration in Gangwon-do Province, where these facilities are concentrated.
Therefore, the objectives of this study are as follows: First, to calculate the proportion and amount of waste materials (specifically plastic waste) used as fuel in the cement manufacturing process; second, to examine the impact of nitrogen oxides on the fine dust (<PM 2.5) generation characteristics in Gangwon-do Province, considering the conversion rate of nitrogen oxides into fine dust; and third, to evaluate the proportion of fine dust attributable to nitrogen oxides. Using these results, the study aims to assess how much the fine dust concentration can be reduced by tightening the nitrogen oxide emission limit for cement plants to the level of waste incineration plants, and to propose policy alternatives to the government and Gangwon-do Province.
Acknowledgments
"This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute(KEITI) funded by the Ministry of Environment(MOE)"
How to cite: Lee, N.-S., Jung, M., and Park, J.-S.: The impact of nitrogen oxides emitted from cement manufacturing facilities on the PM 2.5 concentration in the atmosphere, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2440, https://doi.org/10.5194/egusphere-egu25-2440, 2025.
Air pollution, responsible for the deaths of 7 million people annually, stands as one of the most significant environmental challenges of our time. Among its components, particulate matter (PM) is a key parameter that demands close monitoring due to its adverse effects on human health and its direct and indirect impacts on climate change. The Eastern Mediterranean region, including Turkey, experiences higher levels of warming compared to other areas at the same latitude, making it one of the most climate-vulnerable regions globally. In this context, addressing air pollution, identifying pollutant levels and sources, and implementing mitigation strategies are essential for combating climate change effectively.
In Turkey, the iron and steel industry contributes approximately 7% of the nation’s total greenhouse gas emissions. Within the framework of the European Green Deal and Border Carbon Adjustment Mechanism, the green transformation of this sector is crucial. However, the specific pollutants released into ambient air from this industry and their impacts on human health remain inadequately addressed, particularly for the province of Karabük, where approximately 4 million tons of iron and steel are produced annually. Developing science-based air quality action plans for Karabük requires a comprehensive understanding of the region’s air pollution levels.
This study analyzed fine (PM2.5) and coarse (PM10-2.5) particulate matter samples collected from an air quality monitoring station located in Safranbolu, a tourist hub in Karabük. The sampling periods spanned from August 7 to September 3, 2021, and from November 9 to December 28, 2021. The samples were analyzed using various analytical techniques to determine major ions, elements, and elemental carbon/organic carbon (EC/OC). The findings revealed the urgent need for targeted air pollution reduction measures in Safranbolu to protect both public health and the region's touristic appeal, while addressing the environmental impact of Turkey's largest iron and steel industry based in Karabük.
This study highlights the critical importance of integrating scientific insights into policy and action to reduce air pollution and foster sustainable development in one of Turkey's most industrialized regions.
How to cite: Güllü, G., Aslanoglu, Y., and Ozturk, F.: Air Quality Assessment in Safranbolu (Karabük): A Critical Step Towards Combating Air Pollution in Turkey's Steel Industry Hub, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20059, https://doi.org/10.5194/egusphere-egu25-20059, 2025.
Dust aerosols are a major component of atmospheric aerosols, impacting climate systems and human health. In Asia, dust storms pose significant threats to air quality and public health, particularly in China, Korea, and Japan. Additionally, dust deposition in China's coastal regions supplies trace elements and nutrients that influence microbial communities, affecting marine productivity. Over the Tibetan Plateau, dust reduces snow and ice albedo, accelerating glacial melting. Given these impacts, understanding the sources and contributions of dust aerosols is crucial. Therefore, we focused on typical regions in Asia—North China, Southeast China, the Korea-Japan region, the East China Sea, and the Tibetan Plateau—and selected four primary dust source regions: Eastern Central Asia (ECA), Western Central Asia (WCA), West Asia-South Asia (WA-SA), and North Africa-Middle East (NA-ME).
Previous studies on tracing the sources of airborne dust have largely relied on back-trajectory analysis. However, simply using the number of air mass trajectories passing over a desert to determine dust sources can lead to an overestimation of the relative contribution from source regions. This method, which did not consider the dust load in the transported air masses, resulted in an inaccurate evaluation of the desert-source contribution to the study regions. To address this issue, we present a novel algorithm for source-tracing of airborne dust (STAD), which incorporates satellite and reanalysis-based estimates to more precisely track dust activity and provide a more accurate quantification of source contributions. Overall, ECA emerges as the dominant source of dust affecting East Asia. In regions such as North China and the Korea-Japan area, ECA accounts for 60%-70% of dust transport, with WCA contributing around 20%. In Southeast China and the East China Sea, ECA still plays a major role, contributing 40%-50% of the dust. The Tibetan Plateau, as a dust transit hub in the Northern Hemisphere, has a complex dust source composition. The airborne dust at high altitudes over the Tibetan Plateau shows considerable spatial variation and primarily comes from desert clusters in ECA, WCA, and WA-SA. The Karakum, Taklimakan, and Thar deserts are significant sources of high-altitude airborne dust in the northwest, northeast, and southwest regions of the TP, with average mass loadings (mg m⁻²) contributing rates of 42.2% (32.9), 49.6% (48.3), and 16.4% (32.1), respectively.
This research lays a solid foundation for future studies on the role of dust aerosols in the Asian climate system, including their impacts on water cycles, weather patterns, and long-term environmental changes, providing crucial insights for developing effective mitigation strategies.
How to cite: Tang, J. and Wang, T.: Dominant Remote Sources and Their Potential Contributions to Airborne Dust over Typical Asian Regions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5540, https://doi.org/10.5194/egusphere-egu25-5540, 2025.
Ammonium (NH4+) is an important component of PM2.5, and atmospheric NH4+ mainly comes from secondary reactions of NH3. It significantly impacts air pollution, radiative forcing, and human health. Source apportionment of NH4+ can help improve air quality through emission reductions. Previous studies have primarily focused on ground-level aerosols, and understanding the vertical characteristics of atmospheric NH4+ in the atmospheric boundary layer can deepen our understanding of the sources and transport processes of NH3/NH4+, enhancing the accuracy of atmospheric model simulations. In this study, we collected PM2.5 samples at 8, 120, and 260 m from the 325-meter meteorological tower at the Institute of Atmospheric Physics, Chinese Academy of Sciences (Beijing, China), conducted stable isotope analyses and source apportionment of atmospheric aerosol NH4+ in summer and winter. The summer results show that the concentration of NH4+ rises and its δ15N decreases as the sampling height increases, indicating that regional transport, especially from agricultural sources of NH3/NH4+ in the North China Plain, has a greater impact on high-altitude NH4+ in Beijing. The source apportionment results from the stable isotope mixing model “MixSIAR” show that agricultural sources contribute 47% to NH4+ in ground-level PM2.5, and this increases to 51~56% at higher altitudes. Comparing the observational results with atmospheric chemistry modeling suggests that non-agricultural NH3 emissions in Beijing may be significantly underestimated. Compared to summer, the vertical characteristics in winter are more complex. Still, overall, the concentration of NH4+ increases with height, indicating that both local emissions and regional transport contribute significantly to NH4+, with local emissions having a greater impact near the ground. Combustion-related NH3 emissions, including fossil fuel sources, NH3 slip, and biomass burning, contribute 60% to atmospheric NH4+ during heavily polluted days in winter, exceeding the contributions from volatilization-related NH3 emissions, including livestock breeding, N-fertilizer application, and human waste. In contrast, volatilization-related NH3 emissions dominate on clean days. Biomass burning, especially bioapplication (combustion and use of straw and firewood), may be an important NH3 source that has been overlooked. The study also used atmospheric chemical models to compare the effects of different emission reduction strategies on air pollution control. Compared to reducing a single pollutant (NH3), the simultaneous reduction of NH3 and other pollutants has a more significant effect on lowering PM2.5 concentrations. To improve air quality, future policies could consider implementing simultaneous emission reductions of NH3 and other pollutants for air pollution control.
How to cite: Wu, L., Wang, P., Ren, H., and Fu, P.: Source apportionment of aerosol ammonium in the urban boundary layer of Beijing from tower-based observations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2290, https://doi.org/10.5194/egusphere-egu25-2290, 2025.
Deserts are the primary source of atmospheric dust. Covering over one-third of the Earth’s land surface, deserts play a pivotal role in influencing planetary albedo and dust dynamics.
The Arabian Peninsula is one of the world’s largest dust source regions. It is also affected by natural and anthropogenic pollution of African, Asian, and European origin. As the Arabian Peninsula is highly under-sampled, we have since 2012 established and maintained aerosol monitoring sites at King Abdullah University of Science and Technology (KAUST), as well as in the North-Western part of the Arabian Peninsula, and the Red Sea coast.
The sites incorporate the following instrumentation:
1.
Two CIMEL sun photometers operational since 2012 as a part of the NASA Aerosol Robotic NETwork (AERONET), providing aerosol parameters, reporting data to the NASA Goddard website (http://aeronet.gsfc.nasa.gov/cgi-bin/type_piece_of_map_opera_v2_new).
2.
Hand-held sun photometer (Microtops II). The data are reported to the NASA Maritime Network (http://aeronet.gsfc.nasa.gov/new_web/maritime_aerosol_network.html).
3.
Micro Pulse Lidar (MPL) operating as a part of the NASA MPLNET (http://kimura.gsfc.nasa.gov/site--‐page?site=Kaust). Monitoring the vertical distribution of Aerosols.
4.
We measure aerosol deposition rates on a monthly basis using passive samplers in different several locations (KAUST, 2015-2023; Al Wajh Lagoon, 2021-2022; DUBA & Tabuk,2022 -2023; NEOM project area (NESTOR; ENOWA), 2024 - now)
5.
Mineralogical analysis of deposited aerosols by X-ray diffractometry (XRD)
6.
Measured particle size distributions using Mastersizer3000.
In this study we conduct an analysis of the combined effects of natural and anthropogenic pollution on air quality, climate, and application of renewable energy across the Arabian Peninsula, providing a scientific foundation for model calibration in this region.
Here we report on the data sets collected in 2021- 2025:
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KAUST campus site: Two dust deposition samplers, AERONET, MPL
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Al Wajh Lagoon site: Nine dust deposition samplers
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Duba site: Two dust deposition samplers
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Tabuk site: Two dust deposition samplers
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NEOM, NESTOR Project: Two dust deposition samplers
These data sets, in combination with the available satellite observations, were integrated into the meteorology-chemistry-aerosol model, WRF-Chem, to quantify the aerosol environmental impacts and support environmental decision-making in the region.
How to cite: Shevchenko, I., Wada, Y., and Stenchikov, G.: Aerosol Monitoring at the Western Arabian Peninsula and North region of KSA (NEOM)., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-138, https://doi.org/10.5194/egusphere-egu25-138, 2025.
Aerosols exert a significant influence on the Earth's radiative balance. Black carbon (BC), a potent light-absorbing aerosol primarily generated from incomplete combustion of fossil fuels, biofuels, and biomass, has garnered substantial global research attention due to its substantial impact on regional and global climate change. However, long-term trends in aerosols in the western North Pacific remain poorly understood. Located at 2862 meters above sea level on Lulin Mountain in central Taiwan (23.47°N, 120.87°E), the Lulin Atmospheric Background Station (LABS) stands as the sole high-altitude background station in this region. Operational since the spring of 2006, LABS has been continuously monitoring the impact of various air pollutants through long-range transport. This study utilized continuous real-time measurements of PM10 (2006-2016), PM2.5 (2013-2020), and BC (2008-2020) collected at LABS using two tapered element oscillating microbalances (TEOM 1405) and an aethalometer (AE-31) to investigate their temporal variations, characteristics, and key controlling factors. Correlation analysis was employed to assess the influence of meteorological parameters on their monthly/seasonal burdens. The multi-year annual mean mass concentrations of PM10, PM2.5, and BC were determined to be 9.2, 7.2, and 0.4 µg m-3, respectively. Concentration-weighted trajectory analyses identified northern peninsular Southeast Asia and mainland China as major long-distance source regions for all aerosols at LABS, particularly during spring (March-May) and the northeast monsoon season (October-November), respectively. A slight downward trend in the mass concentrations of ambient aerosols was observed at LABS. This decline may be attributed to a decrease in biomass burning emissions from peninsular Southeast Asia, recent energy policy changes in China, and alterations in regional atmospheric boundary layer dynamics.
How to cite: Pani, S. K. and Lin, N.-H.: Long-term monitoring of ambient aerosols at a subtropical high-altitude mountain site in the western North Pacific, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9126, https://doi.org/10.5194/egusphere-egu25-9126, 2025.
Long-Term Variability of Air Pollutants in the Indo-Gangetic Plain: Drivers, Trends, and Hotspots
Abhishek Saxena
Saxenaabhishek85@gmail.com
This study examines seasonal, monthly, and yearly trends of sulfur dioxide (SO₂), black carbon (BC), carbon monoxide (CO), ozone (O₃), fine particulate matter (PM2.5), and methane (CH₄) across the Indo-Gangetic Plain (IGP) from 2010 to 2024 using MERRA-2 Reanalysis data (0.5° x 0.625° resolution). Elevated concentrations of SO₂, BC, CO, PM2.5, and CH₄ are observed during winter and post-monsoon months due to thermal inversions, stagnant conditions, and emissions from biomass burning and agriculture, while O₃ peaks during summer due to photochemical activity.
Yearly trends show declines in SO₂ and PM2.5 due to emission controls, while BC, CO, and CH₄ remain stable, and O₃ increases slightly with rising precursor emissions. The western IGP, particularly Punjab and Haryana, is identified as a hotspot for SO₂, BC, CO, PM2.5, and CH₄ in post-monsoon, with O₃ hotspots prevalent in summer. Correlations among pollutants vary seasonally, with stronger links in winter and weaker ones during monsoon. These findings highlight the need for targeted, multi-pollutant mitigation strategies tailored to seasonal and regional pollution dynamics in the IGP.
How to cite: Saxena, A.: Long-Term Variability of Air Pollutants in the Indo-Gangetic Plain: Drivers, Trends, and Hotspots, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17261, https://doi.org/10.5194/egusphere-egu25-17261, 2025.
Aerosol formation is a complex process involving numerous molecules, whose identities and environmental variations remain largely uncharted (Bianchi et al., 2019). Computational simulations and property prediction tools have emerged to identify compounds likely to participate in the particle formation process (Elm et al., 2020). In recent years, predictive machine learning models for saturation vapor pressure and partition coefficient estimation have achieved impressive accuracy, with mean absolute errors within one order of magnitude (Besel et al., 2023; Lumiaro et al., 2021); an advancement that enables the categorization of molecules into different volatility regions. However, the interpretability of these models in molecular sciences is often limited unless the molecular descriptor used is easily interpretable. Another challenge is that atmospheric molecules possess unique characteristics that may be overlooked by standard molecular representations developed in other chemical domains (Sandström et al., 2024). We hypothesize that combining sufficiently informative and interpretable descriptors with modern machine learning methods, chemical insight of these largely unknown chemical spaces can be gained in a data-driven way.
In this contribution, we introduce a new interpretable molecular descriptor, ATMOMACCS, specifically tailored to atmospheric molecules. We demonstrate its competitive performance in predicting various thermodynamic properties, such as saturation vapor pressure, vaporization enthalpy, partition coefficients, and glass-transition temperature, equaling or surpassing published results for four distinct atmospheric molecular datasets (Besel et al., 2023; Wang et al., 2017; Ferraz-Caetano et al., 2024; Li et al., 2020). Our descriptor is based on enumerating atmospherically relevant structural motifs, making it readily interpretable for atmospheric chemists. Additionally, in our approach, we analyze the relative importance of these motifs with Shapley Additive Explanations (SHAP) values (Lundberg & Lee, 2017), providing insight into the performance improvements observed. Notably, from this analysis, we found that explicitly counting the number of carbon atoms is particularly important for property prediction, though less so for water-gas phase partition coefficients. Moreover, the analysis shows that general structural motifs are roughly equally important as motifs specific to atmospheric organic chemistry, and the combinations of these two types of motifs were pivotal for predictive performance.
Our molecular descriptor, ATMOMACCS, can serve as a vital tool for advancing data-driven atmospheric science, addressing the need for more customized and accurate modelling in the field. Furthermore, the descriptor’s inherent interpretability and its strong performance in thermodynamic property prediction, with machine learning, show promise for further research in atmospheric chemistry.
This work was supported by the VILMA (Virtual laboratory for molecular level atmospheric transformations) centre of excellence funded by the Academy of Finland under grant 346377.
Besel, V. et al. (2023). Sci. Data 10, 1–11.
Bianchi, F et al. (2019). Chem. Rev. 119, 3472–3509.
Elm, J. et al. (2020) J. Aerosol Sci. 149, 105621.
Ferraz-Caetano, J. et al. (2024). Chemosphere, 359, 142257
Li, Y. et al. (2020). Atmos. Chem. Phys. 20, 8103–8122.
Lumiaro, E. et al. (2021). Atmos. Chem. Phys. 21, 13227–13246.
Lundberg, S. M. and Lee S.-I. (2017). Curran Associates Inc. 30, 9781510860964.
Sandström, H. et al. (2024). Adv. Sci. 11, 2306235.
Wang, C. et al. (2017). Atmos. Chem. Phys. 17, 7529–7540.
How to cite: Lind, L., Sandström, H., and Rinke, P.: ATMOMACCS: Predicting atmospheric compound properties, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5719, https://doi.org/10.5194/egusphere-egu25-5719, 2025.
Atmospheric particles impact our climate and adversely affect air quality and human health (IPCC, 2022; Pozzer et al., 2023). Molecular emissions in the atmosphere can react with ozone and radicals, forming a diverse array of organic compounds that can drive particle formation (Bianchi et al., 2019). However, due to the vast number of potential reactions and precursors, the identities of many of these particle-forming products remain largely unknown. Electron ionization mass spectrometry (EI-MS) is a widely used tool for identifying organic compounds in aerosol particle samples (Franklin et al., 2022; Worton et al., 2017; Hamilton et al., 2004). High-confidence identification relies on matching recorded EI-MS spectra to reference spectra in mass spectral libraries, which contain reference data for known compounds (Laskin et al., 2018). However, the identification of many atmospheric compounds is limited by a lack of reference data for these species (Nozière et al., 2015; Sandström et al., 2024).
In this presentation, I will introduce a simulated reference mass spectrometry dataset for atmospheric organic compounds. Using quantum chemistry and machine learning-based EI-MS simulation tools (Wei et al., 2019; Koopman & Grimme, 2021), we have simulated mass spectra for organic atmospheric compounds from the Master Chemical Mechanism (MCM v3.2, http://mcm.leeds.ac.uk/MCM, Wang et al., 2017). This simulated mass spectral dataset will be made publicly available to support future efforts to identify atmospheric organic compounds and advance our understanding of organic particle formation processes.
This work was supported by the VILMA (Virtual laboratory for molecular level atmospheric transformations) centre of excellence funded by the Research Council of Finland under grant 346377.
Bianchi, F., et al. (2019). Chemical Reviews, 119, 3472–3509.
Franklin, E. B., et al. (2022). Atmospheric Measurement Techniques, 15, 3779–3803.
Hamilton, J. F., et al. (2004). Atmospheric Chemistry and Physics, 4, 1279–1290.
IPCC. (2022). Climate Change 2022: Impacts, Adaptation, and Vulnerability. Cambridge University Press.
Koopman, J., & Grimme, S. (2021). Journal of the American Society for Mass Spectrometry, 32, 1735–1751.
Laskin, J., et al. (2018). Analytical Chemistry, 90, 166–189.
Nozière, B., et al. (2015). Chemical Reviews, 115, 3919–3983.
Pozzer, A., et al. (2023). GeoHealth, 7, 24711403.
Sandström, H., et al. (2024). Advanced Science, 11, 2306235.
Wang, C., et al. (2017). Atmospheric Chemistry and Physics, 17, 7529–7540.
Wei, J. N., et al. (2019). ACS Central Science, 5, 700–708.
Worton, D. R., et al. (2017). Analyst, 142, 2395–2403.
How to cite: Sandström, H. and Rinke, P.: Towards Atmospheric Compound Identification: A Reference Library of Simulated Electron Ionization Mass Spectra, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10129, https://doi.org/10.5194/egusphere-egu25-10129, 2025.
Soot, also commonly known as black carbon (BC) aerosol, is an important short-lived climate forcer. Although global anthropogenic BC emissions from fossil fuel combustion are expected to decrease, BC remains a significant concern in air pollution hotspots in Asia and Africa. Estimates of the global black carbon direct radiative forcing are still subject to considerable uncertainties, ranging from 0.20 to 0.42 Wm⁻². To reduce these uncertainties, it is crucial to improve the representation of the complex soot morphology in simulations of their optical properties and global models. We have investigated various aspects of the optical properties of morphologically complex soot particles, including field and laboratory measurements, and optical simulations of BC as ‘realistic’ fractal aggregates. Investigations conducted in Delhi, a highly polluted urban environment in Asia, confirmed that fractal morphology is important in reducing the overestimation of aerosol light absorption by commonly used light simulation models by 10 to 80%.
To address the computationally expensive nature of fractal simulations, we propose a new metric known as the morphology index (MI). Additionally, to reduce the computational burden of optical simulations of fractal BC particles, we developed a fast and accurate machine learning-based tool for predicting the optical properties of BC fractal aggregates. We have highlighted the importance of the lack of representation of complex soot particles in global models, and offer methods to facilitate their integration into the atmospheric science community.
How to cite: Romshoo, B., Müller, T., Pfeifer, S., Saturno, J., Nowak, A., Yang, Y., Ahlawat, A., Habib, G., Babu, A. S., Madariya, A., Cuesta, A., Deshmukh, S., Patil, J., Michels, T., Kloft, M., and Pöhlker, M.: Advancements in the incorporation of complex soot morphology within atmospheric sciences, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10154, https://doi.org/10.5194/egusphere-egu25-10154, 2025.
Lack of action in climate change mitigation is driving research on solar radiation modification via stratospheric aerosol injection (SAI), i.e., the injection of aerosols or their precursors into the stratosphere to increase Earth’s albedo, inducing global cooling. The idea evolved from observations of the cooling effect of large volcanic eruptions, which emitted SO2 into the stratosphere. Therefore, SAI research mainly focused on sulfur dioxide (SO2) injection, the main precursor of H2SO4 aerosols. However, SO2 injection could lead to adverse side effects such as stratospheric ozone depletion, stratospheric heating, and sizable effects on the large-scale atmospheric circulation. Recent studies suggested that injection of solid particles such as calcite (CaCO3), alumina (Al2O3) and diamond (C) instead of SO2 could reduce some of these adverse side effects. However, the expected improvements are subject to large uncertainties. Heterogeneous chemistry on solid aerosols in the stratosphere can increase ozone depletion by moving passive chlorine reservoir species such as HCl or ClONO2 into their active, ozone depleting form (e.g., ClO). Furthermore, alkaline materials such as CaCO3 are subject to acid-base reactions resulting in an uptake of acidic gases which could impact stratospheric ozone. We constrain some of these uncertainties by experimental work on heterogeneous chemistry of CaCO3 in presence of gaseous HCl, HNO3, and H2SO4 under near-stratospheric conditions. Single crystalline CaCO3 {001} and {104} faces were exposed to controlled gas mixtures closely above either a binary HNO3/H2SO4 or HCl/H2SO4 solution, or a ternary HNO3/HCl/H2SO4 solution for several days. Fixed temperature ranging between -20°C and -60°C were investigated, reaching lower temperature conditions than in previous experiments. Various Relative Humidities (RH) were as well probed. Elastic Recoil Detection Analysis (ERDA), an ion beam analysis technique to obtain elemental concentration depth profile of up to 300 nm, was used to observe surface reaction and diffusion in the material. Uptake coefficients were calculated from these observations. This work presents a path forward for climate intervention research and more specifically for more reliably assessing the impact of SAI of solid particles on stratospheric ozone.
How to cite: Paolucci, C., Vattioni, S., Luo, B., Peter, T., Müller, A., Vockenhuber, C., and Ammann, M.: The heterogeneous reaction of HNO3 and HCl with CaCO3 in the context of stratospheric aerosol injection and its impact on stratospheric ozone, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15947, https://doi.org/10.5194/egusphere-egu25-15947, 2025.
Understanding the properties of aerosols under stratospheric conditions is of particular importance for applications in solar radiation management. Aerosols have the potential to influence the Earth's radiative balance by stratospheric aerosol injection (SAI), which increases albedo and enhances the reflection of solar radiation back into space. By investigating the optical properties of various aerosol types under different environmental conditions, we aim to explore materials for SAI that exhibit albedo-enhancing potential while maintaining stability in the stratosphere.
We have developed an optical trapping system with counter-propagating laser beams coupled with cavity-enhanced Raman spectroscopy to monitor the physical properties of single aerosol particles. This technique, supported by bulk measurements, enables us to determine the wavelength-dependent refractive index under different temperature and relative humidity parameters. Our specially designed optical system allows for rapid changes in temperature and relative humidity using a movable platform while maintaining a stable gradient within the cell reproducing stratospheric conditions. Our findings contribute to a deeper understanding of the suitability of aerosols for climate mitigation strategy and the broader effects of their deployment.
How to cite: Malashevych, S., Odelskii, A., Logozzo, A., and Preston, T.: Characterization of Aerosols for Stratospheric Solar Radiation Management, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13343, https://doi.org/10.5194/egusphere-egu25-13343, 2025.
Organic compounds can constitute roughly half of the sub-micron aerosol mass in the troposphere, necessitating an accurate representation of organic aerosol (OA) in Earth system models (ESMs) to better capture aerosol-climate feedbacks. The secondary fraction of OA (SOA), however, formed through the oxidation of various volatile organic compounds (VOCs) from both natural and anthropogenic sources, complicates the description of OA in ESMs. Most ESMs either assume a non-volatile SOA produced with a constant yield from known precursors or provide a simplistic depiction of its volatility derived from biogenic VOCs, treating the primary fraction of OA (POA) as non-reactive and non-volatile. This approach often fails to accurately reproduce observed OA atmospheric measurement. On the other hand, biological materials such as bacteria, fungal spores, and various fragments released by living organisms into the atmosphere have been widely identified as part of the super-micron OA mass, which most ESMs also inadequately represent.
In the context of the H.F.R.I. project REINFORCE, we focus on improving the representation of atmospheric composition in Earth System Models (ESMs). We present simulations using the volatility basis set (VBS) approach to represent SOA formation, along with incorporating the organic fraction of bioaerosols. These developments are implemented in the state-of-the-art ESM, EC-Earth version 3, which includes interactive aerosols and atmospheric chemistry (EC-Earth3-AerChem). A lite version of the well-documented aerosol module ORACLE, which allows for relatively limited computing resource consumption, has been coupled to the CTM component of EC-Earth3-AerChem to calculate the partitioning and chemical evolution of POA vapors and their changes in volatility. The formation of SOA from semivolatile organic compounds (SVOCs) and intermediate-volatility organic compounds (IVOCs) has been added to the existing SOA formation scheme from biogenic VOCs in the model. Moreover, the three main types of bioaerosols—bacteria, fungal spores, and pollen grains—have been implemented into the model based on interactive bioaerosol schemes that depend on ecosystem types, the leaf area index (LAI), and various meteorological parameters. Bioaerosols in EC-Earth3-AerChem can also be transferred to the soluble aerosol coarse mode due to atmospheric aging processes. Overall, our efforts aim to bridge the gap between model simulations and observations, thereby enhancing our understanding of OA climate impacts.
How to cite: Myriokefalitakis, S., Kakavas, S., Chatziparaschos, M., Karydis, V., Tsimpidi, A., Karathanasopoulos, O., Nieradzik, L., Kanakidou, M., and Pandis, S. N.: An Improved Representation of Organic Aerosol Composition and Atmospheric Evolution in the EC-Earth3-AerChem model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11354, https://doi.org/10.5194/egusphere-egu25-11354, 2025.
Indoor air quality significantly impacts public health as high CO2 levels impair cognition, and elevated particulate matter (PM) increases respiratory diseases. Music practice rooms, often enclosed spaces where musicians spend extended time, are seldom assessed for air quality. This study investigates CO2 and PM levels during violin practice in a music practice room using home-built low-cost air quality box (AQB) systems. Without ventilation, CO2 levels increase nearly linearly, frequently exceeding the 1000 ppm threshold. Simulations of CO2 profiles retrieve the exhaled minute volume of (9 ± 0.7) × 10-3 m3 min-1 person-1 for the violinist. The PM levels vary across five experiments, influenced by factors such as music tempo, rosin, and bow. In the simulation of PM profiles, the deposition rate constants are evaluated as 2.3×10-2, 2.6×10-2, and 9.8×10-2 min-1 for PM1, PM1-2.5, and PM2.5-10, respectively, higher than the gravitational deposition rate constants likely due to advection and turbulence. Smaller particles show higher deposition ratios due to their lower inertia. A model accounting for a decreasing PM generation rate over time, linked to rosin consumption during playing, offers improved prediction accuracy. This variation in rosin is further corroborated by scanning electron microscopy images. Infrared spectroscopy further identified functional groups of rosin and bow hair as factors affecting PM levels across experiments. Additional tests in a room with external circulation systems suggest strategies to maintain low CO2 and PM levels. These findings highlight the importance of adequate ventilation and proper material maintenance to mitigate CO2 and PM levels, thereby improving indoor air quality in music practice rooms to provide healthier environments for musicians, enhancing their well-being and performance.
How to cite: Chen, C.-H., Huang, W.-C., and Hung, H.-M.: Quantitative analysis of indoor CO2 and PM levels during violin performance in a music practice room, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5435, https://doi.org/10.5194/egusphere-egu25-5435, 2025.
Data driven tools are emerging across all domains, largely held under the banner of AI. This includes developments at the interface between academic research and policy implementation. Data science, as a much broader discipline, also requires us to consider the supporting ecosystem of infrastructure and principles that underpin data access and sustainability. The research community is now constantly demonstrating more potential applications within air quality research, from molecular through to global scales. Likewise, the gap between air quality and health research is closing through demonstrable applications of data science approaches.
Alongside this, the UKs Natural Environment Research Council (NERC) Digital Solutions programme is funding a new national facility to connect environmental data with users in the public and private sector, covering health and climate use cases. Taking the unusual approach of asking what end-users may need, in this presentation we present outcomes from workshops held across the UK. We find remaining challenges centre around access and sustainable delivery and discuss the cultural dependencies on the research community. With a focus around the rapidly evolving pace of AI, we present several overarching developments including work on using Large Language Models (LLMs) to improve search and discovery of air quality data.
How to cite: Topping, D. and Kingston, R.: Building a new national facility to connect the UK’s environmental data holdings with end-users across multiple sectors: a case study on linking air quality and health data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16046, https://doi.org/10.5194/egusphere-egu25-16046, 2025.
Atrazine is a selective synthetic triazine herbicide that is primarily used for the management of weeds in corn. Despite being banned in the EU in 2004, it is still used in large quantities globally. Numerous studies have demonstrated adverse effects of atrazine on organisms, particularly its role as an endocrine disruptor causing reproductive dysfunction in vertebrates.1 The occurrence, effects and fate of atrazine in soil and water has been well studied. However, a less investigated pathway for the spread of pesticides is through the atmosphere. Via long-range atmospheric transport (LRAT) pesticides can be transported to pristine environments.2,3
To investigate atmospheric concentrations of atrazine, particulate matter (PM2.5) samples were collected at the rural background station Taunus Observatory, Germany. The collected filters underwent liquid extraction, enrichment, and analysis using high-performance liquid chromatography - high resolution mass spectrometry. Samples from April 2021 to May 2022 were analyzed in two-week increments. For a more detailed examination one intensive two-week period was analyzed. Using the FLEXible PARTicle Lagrangian transport and dispersion model (FLEXPART)4 we identified source regions of atrazine.
The analysis successfully quantified atrazine in PM2.5 samples. Concentrations showed seasonal variation, with high concentrations observed in May and June, corresponding to typical agricultural application periods in the Northern Hemisphere. These results suggest that atrazine detected in the atmosphere is linked to recent usage rather than legacy contamination and wind-driven resuspension from soil. A simple partitioning calculation suggests that atrazine primarily partitions into the partice phase, especially at higher altitudes, which may extend its atmospheric half-life facilitating its potential for LRAT. Backward trajectory modeling indicated that low atrazine concentrations were associated with air masses originating from Europe, whereas higher concentrations corresponded to transatlantic transport from North America.
Our study confirms the presence of atrazine in PM and provides evidence of its LRAT from regions where it is still in use. These results highlight the need for revising pesticide risk assessments accounting for the potential extension of pesticides atmospheric half-life in the condensed phase.5
(1) Rohr, J. R.; McCoy, K. A. A qualitative meta-analysis reveals consistent effects of atrazine on freshwater fish and amphibians. Environmental health perspectives 118, 20–32, 2010.
(2) Mayer, L.; Degrendele, C.; Šenk, P.; Kohoutek, J.; Přibylová, P.; Kukučka, P.; Melymuk, L.; Durand, A.; Ravier, S.; Alastuey, A.; et al. Widespread Pesticide Distribution in the European Atmosphere Questions their Degradability in Air. Environmental science & technology 58, 3342–3352, 2024.
(3) Thurman, E. M.; Cromwell, A. E. Atmospheric Transport, Deposition, and Fate of Triazine Herbicides and Their Metabolites in Pristine Areas at Isle Royale National Park. Environ. Sci. Technol. 34, 3079–3085, 2000.
(4) Bakels, L.; Tatsii, D.; Tipka, A.; Thompson, R.; Dütsch, M.; Blaschek, M.; Seibert, P.; Baier, K.; Bucci, S.; Cassiani, M.; et al. FLEXPART version 11: improved accuracy, efficiency, and flexibility. Geosci. Model Dev. 17, 7595–7627, 2024.
(5) Socorro, J.; Durand, A.; Temime-Roussel, B.; Gligorovski, S.; Wortham, H.; Quivet, E. The persistence of pesticides in atmospheric particulate phase: An emerging air quality issue. Scientific reports 6, 33456, 2016.
How to cite: Vogel, A., Saur, F., and Jesswein, M.: Detection of the Herbizide Atrazine in PM2.5 at a Rural Background Station in Germany: Evidence of Long-Range Atmospheric Transport, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17251, https://doi.org/10.5194/egusphere-egu25-17251, 2025.
Numerous studies have been reported that airport is an important source of ultrafine particles (UFPs, Dp ≤ 100 nm), potentially affecting the health of nearby residents. This study measured UFPs at the Frankfurt/Main international airport as well as in three locations (Raunheim, Schwanheim and Riedberg) at about 5 to 15 km from the airport. Cascade impactors (NanoMOUDI, TSI Inc.) collected UFPs in the size fractions of 56-100, 32-56, 18-32, and 10-18 nm on aluminum substrates during different seasons, allowing the observation of ground-level transport of UFPs. Before the campaign, three models of nanoMOUDI used in this study were collocated at the Goethe University (Riedberg campus) to compare data consistency. Inorganic ions, in particular sulfate, were then analyzed to determine the contribution of sulfur dioxide and sulfuric acid nucleation to the UFP mass concentration. Preliminary results indicate that the sampling efficiencies at UFP stages differed between the three applied impactor models and correction factors might need to be applied for more accurate concentration comparison. The measurements at the Frankfurt/Main international airport during Autumn 2023 showed highest concentrations of sulphate in the 32-56 nm size range, at approximately 40 ng m-3, followed by 56-100 nm, 18-32 nm at ~18 and ~8 ng m-3, respectively, and the lowest concentration was in the 10-18 nm range at ~2 ng m-3. In the measurement campaigns in 2024, the preliminary results show mostly lower average sulfate concentrations in the UFP range at the sites more distant from the airport, ranging from ~ 2 ng m-3 to ~20 ng m-3. Similar relative variations across the UFP size range were observed at the two sites of Raunheim (mostly upwind of the airport) and Riedberg (~ 15 km away from the airport). The highest sulfate concentrations were found in the size range of 56-100 nm and the lowest concentration in the size range of 10-18 nm in both locations. The lowest sulfate concentration was also observed in the 10-18 nm size range in the samples collected at Schwanheim, the sampling site located closer and mostly downwind of the airport. However, the peak sulfate concentration was found in the size range of 32-56 nm, more similar to the relative profile observed directly on the airport. Next to emissions from aircraft engines, the difference in the peak concentration of sulfate may be influenced by several other factors, such as wind direction or other local emissions in the sampling sites. Detailed comparisons of UFP sulfate concentrations together with considerations of local meteorological conditions during the sampling periods will be presented in this contribution.
How to cite: Thi Huyen, T., van Pinxteren, D., Ungeheuer, F., Vogel, A., and Herrmann, H.: Impact of Aircraft Emissions on Ultrafine Particles Sulfate Content around Frankfurt/Main international Airport, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17174, https://doi.org/10.5194/egusphere-egu25-17174, 2025.
Aerosol particle morphology plays a pivotal role in atmospheric processes, particularly heterogeneous chemistry. This study investigates phase transitions and corresponding morphologies of PM2.5 particles collected from three Northeast Asian cities: Seoul, Beijing, and Noto. The samples, representing both polluted and clean environments, were predominantly organic-rich. Observations reveal that PM2.5 particles underwent distinct phase transitions with varying relative humidity (RH), often forming complex three-phase systems. Under ambient conditions, particles predominantly existed in two-liquid or three-phase states, with fully homogeneous or non-liquid states being rare. The organic-rich outer phase serves as a diffusion barrier, limiting the reactive uptake of N₂O₅, especially at lower RH when organic materials become more viscous. These findings will be presented.
How to cite: Song, M., Seong, C., Li, Y., Wu, Z., Lee, J. Y., and Matsuki, A.: Core-shell morphology of PM2.5 from three Northeast Asian cities: Its role in reactive uptake , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1895, https://doi.org/10.5194/egusphere-egu25-1895, 2025.
Keywords: Inorganic ions, ISOROPIIA-II, Sensitivity regime, ALWC, pH
Abstract
The Indo-Gangetic Plain (IGP) is one of the world’s most critical aerosol pollution hotspots, experiencing severe air quality degradation during the transition from summer to cooler months. Enhanced aerosol loading arises from a complex interplay of meteorological conditions, anthropogenic activities, and the region’s unique topography. Fine-mode aerosols, particularly those containing inorganic nitrate, chloride, and ammonium, significantly impact atmospheric chemistry and air quality over this region. The interaction between aerosol, liquid water content (ALWC), and pH is a key determinant of gas-particle partitioning for these species, influencing their atmospheric residence times and depositional velocities. This study presents real-time measurements of inorganic ions (NH4+, SO42--, Cl-, Na+, Mg2+, Ca2+, K+, NO3-) and major gases (SO2, HCl, HONO, HNO3, NH3) in ambient air by deploying the MARGA-R (Monitor for AeRosols and Gases in Ambient Air, Metrohm) instrument during the post-monsoon to winter transition in the Northwestern IGP region, with a focus on the role of temperature, ALWC, and pH in gas-particle partitioning. Using the thermodynamic model ISORROPIA-II, aerosol pH and ALWC were determined and applied in a mathematical framework to elucidate the interactions between inorganic aerosols and major gaseous species and to identify the chemical domains (sensitivity regimes) where aerosol particulate matter is sensitive to NH3 and HNO3. Results illustrate that pH and ALWC conditions during the study period predominantly favoured the partitioning of nitric acid (HNO₃) into particulate nitrate (NO₃⁻). Conversely, ammonium (NH₄⁺) remained mainly in its gaseous form as ammonia (NH₃) over the study site. This distinct partitioning behaviour implies that NH₃ tend to stay localized near their source regions, whereas NO₃⁻ has a greater potential for long-range transport, depending on environmental parameters controlling its mobility and deposition. These findings underscore the critical role of region-specific meteorological processes and shifting source profiles from post-monsoon to winter in influencing secondary inorganic aerosol dynamics. This knowledge offers valuable insights for designing effective pollution mitigation strategies tailored to the unique characteristics of the IGP, emphasizing the importance of considering not just the mass concentration of species but also their sensitivities.
How to cite: Joshi, S., Shaw, C., Rastogi, N., and Singh, A.: Sensitivity of Phase Partitioning of Inorganic Aerosols to pH and ALWC In Northwestern Indo-Gangetic Plain, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-516, https://doi.org/10.5194/egusphere-egu25-516, 2025.
This study integrates long-term data from the Surface Particulate Matter Network (SPARTAN) and the Aerosol Robotic Network (AERONET) to analyze the relationship between aerosol chemical composition and optical properties across 14 globally distributed sites. SPARTAN provides filter-based measurements of PM2.5 chemical species, including ammoniated sulfate (AS), ammonium nitrate (AN), fine soil (FS), and black carbon (BC). In contrast, AERONET offers column-based remote sensing optical data, such as aerosol optical depth (AOD), fine mode fraction (FMF), and single scattering albedo (SSA). By applying a collocation methodology to harmonize the SPARTAN and AERONET datasets, we conducted a detailed investigation of aerosol behavior using data collected from 2016 to 2023. Notable differences in aerosol optical properties were observed according to the mass differences and mass ratios of these chemical components. For FS, an increase in its mass led to decreases in dSSA and FMF, with changes of 0.0045 and 0.033 per 1 µg/m³, respectively. For non-absorbing components like AS and AN, an increase in their mass ratio consistently increased SSA across all wavelengths. This relationship was further supported by grouping data by PM2.5/AOD categories, revealing a correlation coefficient as high as 0.69. This integrated approach bridges the gap between column-based optical properties and surface-level chemical measurements, providing novel insights into aerosol classification and behavior. The findings underscore the importance of combining SPARTAN and AERONET datasets to enhance the understanding of aerosol dynamics and atmospheric impacts.
This work was supported by a grant from the National Institute of Environment Research (NIER), funded by the Ministry of Environment (MOE) of the Republic of Korea (Grant Number NIER-2021-03-03-007) and the Korea Meteorological Administration Research and Development Program under Grant RS-2024-00404042.
How to cite: Eom, S., Kim, J., and Park, S. S.: Bridging Surface and Column Perspectives: Insights into Aerosol Chemical Composition and Optical Properties from SPARTAN and AERONET Data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5464, https://doi.org/10.5194/egusphere-egu25-5464, 2025.
New particle formation (NPF) event happened in the planetary boundary layer contribute more than 60% of ultrafine particles (UFP), which impact the could condensation nuclei (CCN) and the climate. This study retrieved the Particle Number Size Distribution (PNSD) and its relationship with Planetary Boundary Layer Height (PBLH), as well as nucleation mode aerosols trajectories during NPF events in three major Chinese cities: Beijing (BJ), Guangzhou (GZ), and Shanghai (SH). The observation periods include July 2017 to October 2019 (408 effective observation days), November 2019 to March 2020 (127 effective observation days), and April to June 2020 (44 effective observation days) for BJ, GZ, and SH, respectively. The results show that BJ exhibits the highest Number Concentration (PNC) at 2.05 × 10⁶ cm⁻³, while GZ records the highest NPF frequency at 25.98% GZ during the Covid 19 lockdown. In contrast, SH has the lowest PNC at 6.27 × 10⁵ cm⁻³ and the lowest NPF frequency (18.87%). An increase in the PBLH reduces the survival parameter (P), thereby promoting the occurrence of NPF events. A high nucleation-mode PNC also promotes the occurrence of NPF events. The sources of PNSD at the three cities exhibit distinct trajectories on NPF days. The main source of pollutants in BJ is Mongolia, located to the northwest. In GZ, the contribution mainly comes from Jiangxi and Fujian provinces to the northeast, while in SH, the source lies to the northwest. NPF frequencies consistently exceed 25%, predominantly in the northern regions of each site, indicating higher NPF levels in the north compared to the south. This research provides valuable insights for developing strategies to manage the atmospheric environment.
How to cite: Hu, H.: New insights into the boundary layer revolution correlation with new particle formation characteristic in megacities of China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2447, https://doi.org/10.5194/egusphere-egu25-2447, 2025.
Aerosol coagulation is a significant process regarding the dynamics of aerosols in the atmosphere. This process leads to an evolution of the size distribution of aerosols over time induced by particle collisions, and is described by Smoluchowski equation [1].
Accurate numerical simulations of this process are computationally demanding by typical discretization methods [2]. We investigate the effectiveness of the reduced basis method [3] to provide accurate but less demanding simulations, by constructing a reduced order subspace included within the reference high-dimensional space used to provide high fidelity simulations.
We also provide residual-based a posteriori error estimates [4] which enable certification of results up to a given error tolerance. We obtain efficient online model and error estimates as their online computational cost only scale with the reduced dimension, and not the dimension of the high-fidelity model.
By careful design of reduced subspaces we ensure that some properties of the high fidelity operator, such as mass conservation [5], are also preserved by reduced order models.
[1] M. V. Smoluchowski. Drei vortage uber diffusion, brownsche bewegung und koagulation von kolloidteilchen. Physik, 17, 557–585, 1916
[2] E. Debry, and B. Sportisse. Solving aerosol coagulation with size-binning methods. Applied Numerical Mathematics, 57(9), 1008–1020, 2007
[3] A. Quarteroni, et al. Reduced Basis Methods for Partial Differential Equations. Springer Cham. 2015
[4] M. Grepl, and A. Patera, A Posteriori Error Bounds for Reduced-Basis Approximations of Parametrized Parabolic Partial Differential EquationsESAIM: Mathematical Modelling and Numerical Analysis, 39(1), 157-181, 2005
[5] F. Filbet, and P. Laurençot. Mass-conserving solutions and non-conservative approximation to the Smoluchowski coagulation equation. Archiv der Mathematik, 83(6), 558-567, 2004
How to cite: Jacquot, O., Ehrlacher, V., Lelievre, T., and Sartelet, K.: A Reduced Ordel Model for Aerosol Coagulation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11092, https://doi.org/10.5194/egusphere-egu25-11092, 2025.
