Pub Date : 2024-06-11DOI: 10.1016/j.jaerosci.2024.106407
Jooyeon Shin , Mansoo Choi
Taking advantage of continuous, atmospheric, dry, and high-purity aerosol processes, we have developed the three-dimensional (3D) aerosol nanoprinting technique. Precise manipulation of charged aerosol trajectories was realized by controlling the electric field near the substrate with nanoscale resolution to position aerosols in the exact three-dimensional space for finally manufacturing 3D nanostructures in an array form under atmospheric conditions. In our aerosol printing technique, the charged aerosol is a fundamental building block and the electric field line is a drawing tool to print the aerosol. Here, we review how our 3D aerosol nanoprinting technology has been developed and show the importance of aerosol science in controlling the generation of charged aerosols, surface charging, particle motion under Brownian random force, electrical force, inertial force, drag force, and also particle agglomeration for ensuring small and non-agglomerated nanoscale building blocks. We also present possible applications utilizing 3D nanostructures fabricated by our 3D aerosol nanoprinting technique.
{"title":"Three-dimensional aerosol nanoprinting","authors":"Jooyeon Shin , Mansoo Choi","doi":"10.1016/j.jaerosci.2024.106407","DOIUrl":"10.1016/j.jaerosci.2024.106407","url":null,"abstract":"<div><p>Taking advantage of continuous, atmospheric, dry, and high-purity aerosol processes, we have developed the three-dimensional (3D) aerosol nanoprinting technique. Precise manipulation of charged aerosol trajectories was realized by controlling the electric field near the substrate with nanoscale resolution to position aerosols in the exact three-dimensional space for finally manufacturing 3D nanostructures in an array form under atmospheric conditions. In our aerosol printing technique, the charged aerosol is a fundamental building block and the electric field line is a drawing tool to print the aerosol. Here, we review how our 3D aerosol nanoprinting technology has been developed and show the importance of aerosol science in controlling the generation of charged aerosols, surface charging, particle motion under Brownian random force, electrical force, inertial force, drag force, and also particle agglomeration for ensuring small and non-agglomerated nanoscale building blocks. We also present possible applications utilizing 3D nanostructures fabricated by our 3D aerosol nanoprinting technique.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141407334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-11DOI: 10.1016/j.jaerosci.2024.106421
Joseph Heng , Samuel Bechard , David Lach , Jonathan Rothstein , Minghe Wang , Sebastian Ubal , David Julian McClements , Carlos M. Corvalan , Jiakai Lu
Traditional agrichemical formulations are often composed of synthetic ingredients that may exhibit adverse environmental and health effects. Losses from spray drift mean that these potentially toxic ingredients can contaminate the environment and pose significant risks to human health. There is therefore a need for natural ingredients to formulate agrichemical sprays that are non-toxic to humans and less harmful to the environment to ensure greater safety and sustainability. Essential oils are promising candidates as natural biopesticides, but their application is limited due to their phytotoxicity at biocidal-effective dosages. A novel alternative approach utilizes essential oils as dilute oil-in-water emulsion spray adjuvants. This strategy can potentially reduce the usage of conventional pesticide ingredients by synergistically enhancing their effectiveness and reducing losses from spray drift. In this study, we evaluated the anti-drift potential of using plant-derived essential oils and quillaja saponin (a natural surfactant) to prepare dilute oil-in-water emulsions for use as safe and sustainable agrichemical adjuvants. In this study, we evaluated the potential of plant-derived essential oils and quillaja saponin, a natural surfactant, to create dilute oil-in-water emulsions as safe and sustainable agrichemical adjuvants. We found that emulsions made with methylated seed oil (MSO) and quillaja saponin showed similar drift reduction performance to those made with MSO and Tween 80, a synthetic non-ionic surfactant. Carvacrol (oregano and thyme essential oil) in water emulsion was found to increase the spray droplet size, thereby making it a promising ingredient for drift reduction. However, we found that limonene (citrus fruits essential oil) in water emulsion had no drift reduction abilities at the same specifications. The different performances of the two essential oils likely arise from differences in their physicochemical properties, which influence the spray atomization mechanism, specifically the ability of the oil droplets entering and spreading on the water–air interface to form perforations.
{"title":"Evaluating essential oils as biocidal anti-drift adjuvants for safe and sustainable agricultural spray enhancement","authors":"Joseph Heng , Samuel Bechard , David Lach , Jonathan Rothstein , Minghe Wang , Sebastian Ubal , David Julian McClements , Carlos M. Corvalan , Jiakai Lu","doi":"10.1016/j.jaerosci.2024.106421","DOIUrl":"10.1016/j.jaerosci.2024.106421","url":null,"abstract":"<div><p>Traditional agrichemical formulations are often composed of synthetic ingredients that may exhibit adverse environmental and health effects. Losses from spray drift mean that these potentially toxic ingredients can contaminate the environment and pose significant risks to human health. There is therefore a need for natural ingredients to formulate agrichemical sprays that are non-toxic to humans and less harmful to the environment to ensure greater safety and sustainability. Essential oils are promising candidates as natural biopesticides, but their application is limited due to their phytotoxicity at biocidal-effective dosages. A novel alternative approach utilizes essential oils as dilute oil-in-water emulsion spray adjuvants. This strategy can potentially reduce the usage of conventional pesticide ingredients by synergistically enhancing their effectiveness and reducing losses from spray drift. In this study, we evaluated the anti-drift potential of using plant-derived essential oils and quillaja saponin (a natural surfactant) to prepare dilute oil-in-water emulsions for use as safe and sustainable agrichemical adjuvants. In this study, we evaluated the potential of plant-derived essential oils and quillaja saponin, a natural surfactant, to create dilute oil-in-water emulsions as safe and sustainable agrichemical adjuvants. We found that emulsions made with methylated seed oil (MSO) and quillaja saponin showed similar drift reduction performance to those made with MSO and Tween 80, a synthetic non-ionic surfactant. Carvacrol (oregano and thyme essential oil) in water emulsion was found to increase the spray droplet size, thereby making it a promising ingredient for drift reduction. However, we found that limonene (citrus fruits essential oil) in water emulsion had no drift reduction abilities at the same specifications. The different performances of the two essential oils likely arise from differences in their physicochemical properties, which influence the spray atomization mechanism, specifically the ability of the oil droplets entering and spreading on the water–air interface to form perforations.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141391463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-10DOI: 10.1016/j.jaerosci.2024.106419
James Y. Liu , Sahar H. Pradhan , Bernd Zechmann , Saber Hussain , Christie M. Sayes
Industrial processes generate chemicals that have the potential to be aerosolized and inhaled by workers, thereby posing health risks. Traditional toxicology methods employing animal models cannot keep up with the pace of emerging hazards. Nascent in vitro practices face challenges regarding translatability to the real world. To address this critical gap, this study demonstrated a workflow utilizing aerosol characterization in a more realistic exposure scenario: dry powder aerosolization onto the air-liquid interface of lung cells. This study delves into biophysical aspects of lung function by examining lung surfactant inhibition. A set of particulates, including aluminum, aluminum oxide, carbon nanotubes, diesel particulate matter, and colloidal silica, was selected for investigation. Particles were in the respirable regime, with mean aerodynamic diameters ranging from 111 to 162 nm by number and 369–2884 nm by mass. Carbon nanotubes and colloidal silica were identified as surfactant inhibitors. Aerosol doses reduced cell viability, up to 38%, with the most pronounced effects observed in response to exposure to aluminum and diesel particulate matter. Dry particle exposure at the air-liquid interface shows promise even at low doses, compared with nebulization or inoculation to submerged cultures. Our findings underscore the potential of this innovative approach for assessing the hazards of aerosolized particulates and emerging contaminants, offering a more accurate representation of real-world exposure scenarios.
{"title":"Lung surfactant inhibition and cytotoxicity at the air-liquid interface of dry particle aerosols","authors":"James Y. Liu , Sahar H. Pradhan , Bernd Zechmann , Saber Hussain , Christie M. Sayes","doi":"10.1016/j.jaerosci.2024.106419","DOIUrl":"https://doi.org/10.1016/j.jaerosci.2024.106419","url":null,"abstract":"<div><p>Industrial processes generate chemicals that have the potential to be aerosolized and inhaled by workers, thereby posing health risks. Traditional toxicology methods employing animal models cannot keep up with the pace of emerging hazards. Nascent <em>in vitro</em> practices face challenges regarding translatability to the real world. To address this critical gap, this study demonstrated a workflow utilizing aerosol characterization in a more realistic exposure scenario: dry powder aerosolization onto the air-liquid interface of lung cells. This study delves into biophysical aspects of lung function by examining lung surfactant inhibition. A set of particulates, including aluminum, aluminum oxide, carbon nanotubes, diesel particulate matter, and colloidal silica, was selected for investigation. Particles were in the respirable regime, with mean aerodynamic diameters ranging from 111 to 162 nm by number and 369–2884 nm by mass. Carbon nanotubes and colloidal silica were identified as surfactant inhibitors. Aerosol doses reduced cell viability, up to 38%, with the most pronounced effects observed in response to exposure to aluminum and diesel particulate matter. Dry particle exposure at the air-liquid interface shows promise even at low doses, compared with nebulization or inoculation to submerged cultures. Our findings underscore the potential of this innovative approach for assessing the hazards of aerosolized particulates and emerging contaminants, offering a more accurate representation of real-world exposure scenarios.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141325035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-08DOI: 10.1016/j.jaerosci.2024.106408
Naïma Gaudel, Sébastien Bau, Virginie Matera
The characterization of workers’ exposure to airborne metallic ultrafine particles (UFP) has been an increasing issue because of their effects on health, and as many activities are potentially concerned such as welding, oxy-cutting or 3D printing. Determining the particle size distribution of such an aerosol provides a real contribution to the understanding of UFP exposures and associated health effects, as it is directly related to their penetration in the respiratory tract. In this context, it is proposed to optimize the preparation of collection substrates of cascade impactors of airborne metallic UFP. The experimental results confirm that the collection substrates have to be prepared beforehand by coating them with a high-vacuum-resistant silicone grease. The results highlight that this grease has to be preliminarily dissolved in a heptane-based solution with a mass ratio grease-solvent of 7.5%, and then deposited on the substrate with a target height of 9 . Applying this protocol ensures a reproducible and representative determination of the particle size distribution, allowing the phenomena of particle bouncing and reentrainment to be significantly reduced. It is also shown that coated collection substrates remain stable for several months in terms of mass, and that the samples collected remain stable during transport thanks to the improvement of particle cohesion on the coated membrane.
由于空气中的金属超细粒子(UFP)对健康的影响,以及焊接、氧切割或 3D 打印等许多活动可能涉及的超细粒子,对工人暴露于空气中的超细粒子的特征描述已成为一个日益重要的问题。确定此类气溶胶的粒度分布有助于真正了解超细粒子的暴露和相关健康影响,因为这直接关系到它们在呼吸道中的穿透力。在这种情况下,建议优化空气中金属 UFP 级联冲击器收集基质的制备。实验结果证实,必须事先在收集基板上涂抹一层耐高真空的硅脂。实验结果表明,这种硅脂必须预先溶解在庚烷溶液中,硅脂与溶剂的质量比为 7.5%,然后沉积在基底上,目标高度为 9 μm。采用这种方案可确保粒度分布测定的可重复性和代表性,从而大大减少颗粒反弹和再裹挟现象。实验还表明,涂层收集基底的质量可保持稳定数月之久,而且由于涂层膜上颗粒的内聚力提高,收集的样品在运输过程中也能保持稳定。
{"title":"Technical note: Optimization of the preparation of cascade impactors collection substrates for airborne metallic ultrafine particle sampling","authors":"Naïma Gaudel, Sébastien Bau, Virginie Matera","doi":"10.1016/j.jaerosci.2024.106408","DOIUrl":"https://doi.org/10.1016/j.jaerosci.2024.106408","url":null,"abstract":"<div><p>The characterization of workers’ exposure to airborne metallic ultrafine particles (UFP) has been an increasing issue because of their effects on health, and as many activities are potentially concerned such as welding, oxy-cutting or 3D printing. Determining the particle size distribution of such an aerosol provides a real contribution to the understanding of UFP exposures and associated health effects, as it is directly related to their penetration in the respiratory tract. In this context, it is proposed to optimize the preparation of collection substrates of cascade impactors of airborne metallic UFP. The experimental results confirm that the collection substrates have to be prepared beforehand by coating them with a high-vacuum-resistant silicone grease. The results highlight that this grease has to be preliminarily dissolved in a heptane-based solution with a mass ratio grease-solvent of 7.5%, and then deposited on the substrate with a target height of 9 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>. Applying this protocol ensures a reproducible and representative determination of the particle size distribution, allowing the phenomena of particle bouncing and reentrainment to be significantly reduced. It is also shown that coated collection substrates remain stable for several months in terms of mass, and that the samples collected remain stable during transport thanks to the improvement of particle cohesion on the coated membrane.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141325034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-08DOI: 10.1016/j.jaerosci.2024.106416
Fanny Bergman , Axel C. Eriksson , Marten Spanne , Lena Ohlsson , Irma Mahmutovic Persson , Lena Uller , Jenny Rissler , Christina Isaxon
The toxicity of particulate matter (PM) is dependent on particle physical and chemical properties and is commonly studied using in vivo and in vitro approaches. PM to be used for in vivo and in vitro studies is often collected on filters and then extracted from the filter surface using a solvent. During extraction and further PM sample handling, particle properties change, but this is often neglected in toxicology studies, with possible implications for health effect assessment. To address the current lack of knowledge and investigate changes in particle properties further, ambient PM with diameter less than 2.5 μm (PM2.5) was collected on filters at an urban site and extracted using a standard methanol protocol. After extraction, the PM was dried, dispersed in water and subsequently nebulized. The resulting aerosol properties were then compared to those of the ambient PM2.5. The number size distribution for the nebulized aerosol resembled the ambient in terms of the main mode diameter, and >90 % of particle mass in the nebulized size distribution was still in the PM2.5 range. Black carbon made up a similar fraction of PM mass in nebulized as in ambient aerosol. The sulfate content in the nebulized aerosol seemed depleted and the chemical composition of the organic fraction was altered, but it remains unclear to what extent other non-refractory components were affected by the extraction process. Trace elements were not distributed equally across size fractions, neither in ambient nor nebulized PM. Change in chemical form was studied for zinc, copper and iron. The form did not appear to be different between the ambient and nebulized PM for iron and copper, but seemed altered for zinc. Although many of the studied properties were reasonably well preserved, it is clear that the PM2.5 collection and re-aerosolization process affects particles, and thus potentially also their health effects. Because of this, the effect of the particle collection and extraction process must be considered when evaluating cellular and physiological outcomes upon PM2.5 exposure.
{"title":"Physicochemical metamorphosis of re-aerosolized urban PM2.5","authors":"Fanny Bergman , Axel C. Eriksson , Marten Spanne , Lena Ohlsson , Irma Mahmutovic Persson , Lena Uller , Jenny Rissler , Christina Isaxon","doi":"10.1016/j.jaerosci.2024.106416","DOIUrl":"10.1016/j.jaerosci.2024.106416","url":null,"abstract":"<div><p>The toxicity of particulate matter (PM) is dependent on particle physical and chemical properties and is commonly studied using <em>in vivo</em> and <em>in vitro</em> approaches. PM to be used for <em>in vivo</em> and <em>in vitro</em> studies is often collected on filters and then extracted from the filter surface using a solvent. During extraction and further PM sample handling, particle properties change, but this is often neglected in toxicology studies, with possible implications for health effect assessment. To address the current lack of knowledge and investigate changes in particle properties further, ambient PM with diameter less than 2.5 μm (PM<sub>2.5</sub>) was collected on filters at an urban site and extracted using a standard methanol protocol. After extraction, the PM was dried, dispersed in water and subsequently nebulized. The resulting aerosol properties were then compared to those of the ambient PM<sub>2.5</sub>. The number size distribution for the nebulized aerosol resembled the ambient in terms of the main mode diameter, and >90 % of particle mass in the nebulized size distribution was still in the PM<sub>2.5</sub> range. Black carbon made up a similar fraction of PM mass in nebulized as in ambient aerosol. The sulfate content in the nebulized aerosol seemed depleted and the chemical composition of the organic fraction was altered, but it remains unclear to what extent other non-refractory components were affected by the extraction process. Trace elements were not distributed equally across size fractions, neither in ambient nor nebulized PM. Change in chemical form was studied for zinc, copper and iron. The form did not appear to be different between the ambient and nebulized PM for iron and copper, but seemed altered for zinc. Although many of the studied properties were reasonably well preserved, it is clear that the PM<sub>2.5</sub> collection and re-aerosolization process affects particles, and thus potentially also their health effects. Because of this, the effect of the particle collection and extraction process must be considered when evaluating cellular and physiological outcomes upon PM<sub>2.5</sub> exposure.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0021850224000831/pdfft?md5=6a66739e40e2744a3e62f06e3cbca8ab&pid=1-s2.0-S0021850224000831-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141398625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-27DOI: 10.1016/j.jaerosci.2024.106406
Roope Halonen
Accurate predictions of nucleation and atomic-level estimates of cluster properties in gas-phase chemical physics have proven challenging. These challenges arise from two primary sources: finite-size effects associated with nanoscopic particles and the emergence of non-standard thermodynamics, particularly at elevated temperatures. This study reexamines the formation of argon clusters using established methodologies such as atomistic simulations, configurational sampling, and statistical thermochemistry. To enhance the representation of condensed-phase argon, we employ an ab initio-based two-body potential, complemented by a three-body Axilrod–Teller potential. Additionally, we address the impact of anharmonicities on cluster stabilities using a recently developed extension to the standard statistical cluster model. The employed anharmonic model is rigorously benchmarked against molecular dynamics simulations. The subsequent analysis demonstrates a robust and consistent agreement between our model and experimental data. Our analysis covers nearly every experimental data point collected between 1971 and 2010, offering valuable insights into the predictive capabilities of the model. Moreover, in contrast to previous studies, our findings indicate that individual measurements are consistently in alignment with each other.
事实证明,在气相化学物理中对成核的精确预测和原子级的团簇特性估计具有挑战性。这些挑战主要来自两个方面:与纳米粒子相关的有限尺寸效应和非标准热力学的出现,尤其是在高温条件下。本研究采用原子模拟、构型采样和统计热化学等成熟方法重新研究了氩簇的形成。为了加强对凝聚相氩的表征,我们采用了一种基于 ab initio 的二体势垒,并辅以三体 Axilrod-Teller 势垒。此外,我们还利用最近开发的标准统计簇模型扩展功能,解决了非谐波对簇稳定性的影响问题。所采用的非谐波模型经过了严格的分子动力学模拟基准测试。随后的分析表明,我们的模型与实验数据之间具有稳健而一致的一致性。我们的分析涵盖了 1971 年至 2010 年间收集的几乎所有实验数据点,为模型的预测能力提供了宝贵的见解。此外,与以往的研究不同,我们的研究结果表明,各个测量数据之间始终保持一致。
{"title":"Atomistic insights into argon clusters and nucleation dynamics","authors":"Roope Halonen","doi":"10.1016/j.jaerosci.2024.106406","DOIUrl":"https://doi.org/10.1016/j.jaerosci.2024.106406","url":null,"abstract":"<div><p>Accurate predictions of nucleation and atomic-level estimates of cluster properties in gas-phase chemical physics have proven challenging. These challenges arise from two primary sources: finite-size effects associated with nanoscopic particles and the emergence of non-standard thermodynamics, particularly at elevated temperatures. This study reexamines the formation of argon clusters using established methodologies such as atomistic simulations, configurational sampling, and statistical thermochemistry. To enhance the representation of condensed-phase argon, we employ an <em>ab initio</em>-based two-body potential, complemented by a three-body Axilrod–Teller potential. Additionally, we address the impact of anharmonicities on cluster stabilities using a recently developed extension to the standard statistical cluster model. The employed anharmonic model is rigorously benchmarked against molecular dynamics simulations. The subsequent analysis demonstrates a robust and consistent agreement between our model and experimental data. Our analysis covers nearly every experimental data point collected between 1971 and 2010, offering valuable insights into the predictive capabilities of the model. Moreover, in contrast to previous studies, our findings indicate that individual measurements are consistently in alignment with each other.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141249403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1016/j.jaerosci.2024.106388
Laura Fierce, Yu Yao, Richard Easter, Po-Lun Ma, Jian Sun, Hui Wan, Kai Zhang
Aerosol effects on clouds and radiation are a large source of uncertainty in our understanding of human impacts on the climate system. Uncertainty in aerosol effects results from uncertainty in parameter values, known as parametric uncertainty, and from uncertainty from the model’s structure, known as structural uncertainty. While previous studies have assessed the impact of parametric uncertainty on modeled forcing, structural errors from the numerical representation of particle distributions and their dynamics have not been well quantified. Here we present a framework for quantifying error in aerosol size distributions and cloud condensation nuclei activity, which we apply to the widely used 4-mode version of the Modal Aerosol Module (MAM4). Box model predictions from the MAM4 are evaluated against the Particle Monte Carlo Model for Simulating Aerosol Interactions and Chemistry (PartMC-MOSAIC), a benchmark model that tracks the evolution of individual particles. We show that size distributions simulated by MAM4 diverge from those simulated by PartMC-MOSAIC after only a few hours of aging by condensation and coagulation in polluted conditions, which leads to large errors in modeled cloud condensation nuclei concentrations. We find that differences between MAM4 and PartMC-MOSAIC are largest under polluted conditions, where the size distribution evolves rapidly though aging. These findings indicate that structural error in modeled aerosol properties is a key factor contributing to uncertainty in aerosol forcing.
{"title":"Quantifying structural errors in cloud condensation nuclei activity from reduced representation of aerosol size distributions","authors":"Laura Fierce, Yu Yao, Richard Easter, Po-Lun Ma, Jian Sun, Hui Wan, Kai Zhang","doi":"10.1016/j.jaerosci.2024.106388","DOIUrl":"10.1016/j.jaerosci.2024.106388","url":null,"abstract":"<div><p>Aerosol effects on clouds and radiation are a large source of uncertainty in our understanding of human impacts on the climate system. Uncertainty in aerosol effects results from uncertainty in parameter values, known as parametric uncertainty, and from uncertainty from the model’s structure, known as structural uncertainty. While previous studies have assessed the impact of parametric uncertainty on modeled forcing, structural errors from the numerical representation of particle distributions and their dynamics have not been well quantified. Here we present a framework for quantifying error in aerosol size distributions and cloud condensation nuclei activity, which we apply to the widely used 4-mode version of the Modal Aerosol Module (MAM4). Box model predictions from the MAM4 are evaluated against the Particle Monte Carlo Model for Simulating Aerosol Interactions and Chemistry (PartMC-MOSAIC), a benchmark model that tracks the evolution of individual particles. We show that size distributions simulated by MAM4 diverge from those simulated by PartMC-MOSAIC after only a few hours of aging by condensation and coagulation in polluted conditions, which leads to large errors in modeled cloud condensation nuclei concentrations. We find that differences between MAM4 and PartMC-MOSAIC are largest under polluted conditions, where the size distribution evolves rapidly though aging. These findings indicate that structural error in modeled aerosol properties is a key factor contributing to uncertainty in aerosol forcing.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141140959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1016/j.jaerosci.2024.106392
Egor V. Demidov , Ogochukwu Y. Enekwizu , Ali Hasani , Chong Qiu , Alexei F. Khalizov
Atmospheric soot (or black carbon, BC) affects climate through solar light absorption and scattering, which depend strongly on the particle morphology and composition. Initially, soot particles are fractal aggregates of spherules made of elemental carbon (EC), but condensation of atmospheric trace vapors adds non-EC materials and often results in particle compaction. The optical properties of such processed soot differ from those of fractal soot, and the changes are caused both by particle volume increase from coating addition and by restructuring of the EC backbone. In laboratory studies of soot optics, surrogates such as carbon black (CB) and nigrosin are often used in place of flame-generated soot. Our goal was to investigate if compositional and morphological differences between these surrogates and soot may produce different processing rates and optical responses. In our experiments, we generated fractal soot, compact CB, agglomerated CB (via coagulation of compact CB), and spherical nigrosin aerosol particles, subjected them to supersaturated vapor of dioctyl sebacate (DOS) to form a coating layer, and investigated the morphological response of these four particle types to coating addition and removal. Using coated and coated-denuded aerosol particles with known composition and morphology, we quantified the contributions of volume increase and restructuring to light scattering and absorption enhancements. By comparing experimental measurements against different particle optics models we show that it is crucial to account for larger, multiply charged particles present in the mobility-classified aerosol. Producing a disproportionately high contribution to absolute values of optical cross sections, such larger particles also result in lesser optical enhancements due to slower growth by vapor condensation. Scattering increases for all particle types due to the addition of a coating layer, and also due to restructuring for fractal soot (strongly) and agglomerated CB (weakly). Absorption increases only due to coating addition caused by the coating layer for all particle types. We find that simple optical models, such as Mie, are often sufficient to provide reasonable closure with experimental results for bare and coated aerosols, but only after accounting for the contributions from multiply charged particles, both in terms of their stronger optical cross sections and slower condensational growth. We conclude that CB is an appropriate surrogate for soot in aerosol aging studies where the effects of restructuring do not need to be considered and that nigrosin can be used as a general model for light-absorbing aerosols but is not representative of optical properties of soot.
{"title":"Differences and similarities in optical properties of coated fractal soot and its surrogates","authors":"Egor V. Demidov , Ogochukwu Y. Enekwizu , Ali Hasani , Chong Qiu , Alexei F. Khalizov","doi":"10.1016/j.jaerosci.2024.106392","DOIUrl":"10.1016/j.jaerosci.2024.106392","url":null,"abstract":"<div><p>Atmospheric soot (or black carbon, BC) affects climate through solar light absorption and scattering, which depend strongly on the particle morphology and composition. Initially, soot particles are fractal aggregates of spherules made of elemental carbon (EC), but condensation of atmospheric trace vapors adds non-EC materials and often results in particle compaction. The optical properties of such processed soot differ from those of fractal soot, and the changes are caused both by particle volume increase from coating addition and by restructuring of the EC backbone. In laboratory studies of soot optics, surrogates such as carbon black (CB) and nigrosin are often used in place of flame-generated soot. Our goal was to investigate if compositional and morphological differences between these surrogates and soot may produce different processing rates and optical responses. In our experiments, we generated fractal soot, compact CB, agglomerated CB (via coagulation of compact CB), and spherical nigrosin aerosol particles, subjected them to supersaturated vapor of dioctyl sebacate (DOS) to form a coating layer, and investigated the morphological response of these four particle types to coating addition and removal. Using coated and coated-denuded aerosol particles with known composition and morphology, we quantified the contributions of volume increase and restructuring to light scattering and absorption enhancements. By comparing experimental measurements against different particle optics models we show that it is crucial to account for larger, multiply charged particles present in the mobility-classified aerosol. Producing a disproportionately high contribution to absolute values of optical cross sections, such larger particles also result in lesser optical enhancements due to slower growth by vapor condensation. Scattering increases for all particle types due to the addition of a coating layer, and also due to restructuring for fractal soot (strongly) and agglomerated CB (weakly). Absorption increases only due to coating addition caused by the coating layer for all particle types. We find that simple optical models, such as Mie, are often sufficient to provide reasonable closure with experimental results for bare and coated aerosols, but only after accounting for the contributions from multiply charged particles, both in terms of their stronger optical cross sections and slower condensational growth. We conclude that CB is an appropriate surrogate for soot in aerosol aging studies where the effects of restructuring do not need to be considered and that nigrosin can be used as a general model for light-absorbing aerosols but is not representative of optical properties of soot.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141144958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-18DOI: 10.1016/j.jaerosci.2024.106402
Joseph Breerwood, Lulin Jiang, Md Shakil Ahmed
The present study investigates the effect of the internal swirling atomizing air on the injector near-field spray characteristics and spray stability of a novel twin-fluid injector named swirl burst (SB) injector by incorporating an internal swirl. It involves primary atomization by internal bubbling and bubble bursting, and external secondary atomization by shear layer instabilities. A previous design integrated an external swirl and successfully enhanced the secondary atomization. It generated fine droplets immediately, rather than a typical jet core/film of conventional airblast or pressure swirl atomizers. It thus resulted in compact and ultra-clean lean-premixed combustion of distinct fuels, potentially enabling small-core fuel-flexible combustors. The current work aims to further enhance the primary atomization. The near-field flow patten and droplet size distribution and dynamics are investigated using high-speed laser-driven shadowgraph imaging accompanied by the internal bubble visualization. Results reveal that the internal swirl leads to more uniform, smaller and faster-moving bubbles that concentrate at the internal liquid tube tip regardless of the increased flow rates, generating ultra-stable and finer sprays with a wider working range, compared to the injector without the internal swirl. The frequency spectrum analysis of droplet sizes consistently substantiates the significantly improved spray steadiness, enhancing clean spray combustion stability.
{"title":"Near-field spray characteristics and steadiness of a novel twin-fluid injector with enhanced primary atomization","authors":"Joseph Breerwood, Lulin Jiang, Md Shakil Ahmed","doi":"10.1016/j.jaerosci.2024.106402","DOIUrl":"10.1016/j.jaerosci.2024.106402","url":null,"abstract":"<div><p>The present study investigates the effect of the internal swirling atomizing air on the injector near-field spray characteristics and spray stability of a novel twin-fluid injector named swirl burst (SB) injector by incorporating an internal swirl. It involves primary atomization by internal bubbling and bubble bursting, and external secondary atomization by shear layer instabilities. A previous design integrated an external swirl and successfully enhanced the secondary atomization. It generated fine droplets immediately, rather than a typical jet core/film of conventional airblast or pressure swirl atomizers. It thus resulted in compact and ultra-clean lean-premixed combustion of distinct fuels, potentially enabling small-core fuel-flexible combustors. The current work aims to further enhance the primary atomization. The near-field flow patten and droplet size distribution and dynamics are investigated using high-speed laser-driven shadowgraph imaging accompanied by the internal bubble visualization. Results reveal that the internal swirl leads to more uniform, smaller and faster-moving bubbles that concentrate at the internal liquid tube tip regardless of the increased flow rates, generating ultra-stable and finer sprays with a wider working range, compared to the injector without the internal swirl. The frequency spectrum analysis of droplet sizes consistently substantiates the significantly improved spray steadiness, enhancing clean spray combustion stability.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141133739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-18DOI: 10.1016/j.jaerosci.2024.106400
Yuyang Li , Runlong Cai , Rujing Yin , Xiaoxiao Li , Yi Yuan , Zhaojin An , Junchen Guo , Dominik Stolzenburg , Markku Kulmala , Jingkun Jiang
Organic aerosols are ubiquitous, playing important roles in various atmospheric physicochemical processes such as the formation of cloud droplets and haze. Condensation of organic vapors, as a net effect of association with particles and dissociation from the condensed phase, is a fundamental process that drives the formation of organic aerosols. Kinetic models are often used to simulate the condensation fluxes of low-volatility organic vapors and aerosol growth. However, the widely used kinetic growth models usually calculate the evaporation of a certain species based on previous particulate compositions, without including the co-condensation of other species. Here we present a new kinetic partitioning method for calculating the condensation fluxes of organic vapors in a wide volatility range with low computational cost. In this method, the organic vapors are assumed to be in a quasi-steady state, but never reach real association-dissociation equilibrium during the simultaneous condensation of multiple species. We show a good consistency between the kinetic partitioning method and kinetic models in simulating particle mass fractions and condensation fluxes. Under relevant atmospheric conditions, we reveal that the kinetic partitioning method also reproduce the trend that low-volatility species are almost non-volatile while volatile organic compounds almost reach association-dissociation equilibrium, while there is a transition regime between them. This transition regime varies with atmospheric conditions, such as temperature and vapor concentrations. Compared with previous studies combining kinetic growth methods with equilibrium partitioning theories to simplify the condensation flux calculation, this method helps to improve accuracy without a significant expense of computation cost, and it can be applied in a wider range of atmospheric conditions such as in extremely cold atmospheres and polluted exhaust plumes.
{"title":"A kinetic partitioning method for simulating the condensation mass flux of organic vapors in a wide volatility range","authors":"Yuyang Li , Runlong Cai , Rujing Yin , Xiaoxiao Li , Yi Yuan , Zhaojin An , Junchen Guo , Dominik Stolzenburg , Markku Kulmala , Jingkun Jiang","doi":"10.1016/j.jaerosci.2024.106400","DOIUrl":"https://doi.org/10.1016/j.jaerosci.2024.106400","url":null,"abstract":"<div><p>Organic aerosols are ubiquitous, playing important roles in various atmospheric physicochemical processes such as the formation of cloud droplets and haze. Condensation of organic vapors, as a net effect of association with particles and dissociation from the condensed phase, is a fundamental process that drives the formation of organic aerosols. Kinetic models are often used to simulate the condensation fluxes of low-volatility organic vapors and aerosol growth. However, the widely used kinetic growth models usually calculate the evaporation of a certain species based on previous particulate compositions, without including the co-condensation of other species. Here we present a new kinetic partitioning method for calculating the condensation fluxes of organic vapors in a wide volatility range with low computational cost. In this method, the organic vapors are assumed to be in a quasi-steady state, but never reach real association-dissociation equilibrium during the simultaneous condensation of multiple species. We show a good consistency between the kinetic partitioning method and kinetic models in simulating particle mass fractions and condensation fluxes. Under relevant atmospheric conditions, we reveal that the kinetic partitioning method also reproduce the trend that low-volatility species are almost non-volatile while volatile organic compounds almost reach association-dissociation equilibrium, while there is a transition regime between them. This transition regime varies with atmospheric conditions, such as temperature and vapor concentrations. Compared with previous studies combining kinetic growth methods with equilibrium partitioning theories to simplify the condensation flux calculation, this method helps to improve accuracy without a significant expense of computation cost, and it can be applied in a wider range of atmospheric conditions such as in extremely cold atmospheres and polluted exhaust plumes.</p></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141096133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}