Pub Date : 2025-09-01Epub Date: 2025-06-22DOI: 10.1016/j.jaerosci.2025.106639
Donghui Zhou , Jia Liu , Jinbao Han , Jianfei Luo , Bo Yin
Optical properties of black carbon (BC) aerosols are essential for assessing atmospheric radiation and climate change, but fast and accurate optical calculation for BC with complex structures is still a challenge. In this study, a quick optical modeling method for BC coated by different materials under various humidities is developed based on the multiple-sphere T-matrix (MSTM) simulation and support-vector-machine (SVM) algorithm. The typical closed-cell, coated-aggregate, and partially-coated BC models with BC monomers ranging from 50 to 2000 and BC volume fractions ranging from 0.05 to 0.70 are employed, and the relative errors (REs) and determination coefficients (R2) are used to investigate the prediction performance of optical properties based on SVM. Results show that the SVM predicted optical properties, such as optical efficiency, asymmetry factor, single scattering albedo, and lidar ratio, overall agree well with the properties simulated using MSTM. The prediction performance could be influenced by coating structure and morphological parameters, most of the values of REs and R2 were smaller than about 20 % and larger than about 0.85, respectively. The relative humidities (RHs) and coating materials slightly deteriorate the performance of SVM. With RHs increasing from 0 % to 95 %, or the coatings become non-absorbing organic carbon (OC) and brown carbon (BrC), the largest REs increase to over 30 %, while most of the R2 is still larger than 0.85. This study presented a promising optical modeling method for BC aerosols, and it could be further improved with the development of machine learning.
{"title":"Performance investigation of machine learning for optical modeling of black carbon aerosols with different coatings and humidities","authors":"Donghui Zhou , Jia Liu , Jinbao Han , Jianfei Luo , Bo Yin","doi":"10.1016/j.jaerosci.2025.106639","DOIUrl":"10.1016/j.jaerosci.2025.106639","url":null,"abstract":"<div><div>Optical properties of black carbon (BC) aerosols are essential for assessing atmospheric radiation and climate change, but fast and accurate optical calculation for BC with complex structures is still a challenge. In this study, a quick optical modeling method for BC coated by different materials under various humidities is developed based on the multiple-sphere <em>T</em>-matrix (MSTM) simulation and support-vector-machine (SVM) algorithm. The typical closed-cell, coated-aggregate, and partially-coated BC models with BC monomers ranging from 50 to 2000 and BC volume fractions ranging from 0.05 to 0.70 are employed, and the relative errors (REs) and determination coefficients (R<sup>2</sup>) are used to investigate the prediction performance of optical properties based on SVM. Results show that the SVM predicted optical properties, such as optical efficiency, asymmetry factor, single scattering albedo, and lidar ratio, overall agree well with the properties simulated using MSTM. The prediction performance could be influenced by coating structure and morphological parameters, most of the values of REs and R<sup>2</sup> were smaller than about 20 % and larger than about 0.85, respectively. The relative humidities (RHs) and coating materials slightly deteriorate the performance of SVM. With RHs increasing from 0 % to 95 %, or the coatings become non-absorbing organic carbon (OC) and brown carbon (BrC), the largest REs increase to over 30 %, while most of the R<sup>2</sup> is still larger than 0.85. This study presented a promising optical modeling method for BC aerosols, and it could be further improved with the development of machine learning.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106639"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364563","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 : 2025-09-01Epub Date: 2025-07-05DOI: 10.1016/j.jaerosci.2025.106647
Sreeyuth Lal, David Grand-Maitre, Yu-Shan Chin, Luke Lebel
Ventilation modes significantly impact the dispersion and deposition of pathogen-laden aerosols in indoor environments, thereby affecting both direct and indirect disease transmission. This study investigates the influence of thermal stratification as a result of the ventilation mode. Several HVAC parameters are examined in the experiments, including vent location, air exchange rate, heating or cooling mode, and the resulting conditions, which can be either stratified or mixed. Test aerosols are fluorescein particles in the 0.3–5 μm size range, characteristic of those reported in the literature for human expiratory activities, and releases are complemented by co-injection of CO2 to allow for a broader measurement of dispersion. A body heat simulator and a heated injection system are used to account for the buoyant plume rise of human exhalation and body heat. Particle deposition on horizontal and vertical surfaces is quantified through deposition plates located throughout the test chamber. Dispersion and deposition are as expected from a lumped box model when the ventilation mode promotes mixed conditions (air exchange rates of 0.5–5 h−1). When conditions were thermally stratified, the location of the return vent had a substantial impact on the measured concentrations; locating the return at the floor creates a dead-end volume at the top half (breathing zone) of the room where aerosols accumulate, whereas positioning the return on the ceiling offer the most efficient mode for removing contaminants. The deposition was an important sink for airborne particulates, and deposition observed on the walls and ceiling was higher than anticipated. There are novel comparisons between the deposition rates and measured friction velocities in the room to attempt to qualify the relative roles of turbulence, gravity, and Brownian deposition mechanisms; however, most of the deposition could be attributed to electrostatic effects. The findings in this study can have serious ramifications for developing HVAC designs that aim to minimize the risk of indoor disease transmission.
{"title":"Experimental investigation on the impact of thermal stratification on aerosol behavior in indoor environments","authors":"Sreeyuth Lal, David Grand-Maitre, Yu-Shan Chin, Luke Lebel","doi":"10.1016/j.jaerosci.2025.106647","DOIUrl":"10.1016/j.jaerosci.2025.106647","url":null,"abstract":"<div><div>Ventilation modes significantly impact the dispersion and deposition of pathogen-laden aerosols in indoor environments, thereby affecting both direct and indirect disease transmission. This study investigates the influence of thermal stratification as a result of the ventilation mode. Several HVAC parameters are examined in the experiments, including vent location, air exchange rate, heating or cooling mode, and the resulting conditions, which can be either stratified or mixed. Test aerosols are fluorescein particles in the 0.3–5 μm size range, characteristic of those reported in the literature for human expiratory activities, and releases are complemented by co-injection of CO<sub>2</sub> to allow for a broader measurement of dispersion. A body heat simulator and a heated injection system are used to account for the buoyant plume rise of human exhalation and body heat. Particle deposition on horizontal and vertical surfaces is quantified through deposition plates located throughout the test chamber. Dispersion and deposition are as expected from a lumped box model when the ventilation mode promotes mixed conditions (air exchange rates of 0.5–5 h<sup>−1</sup>). When conditions were thermally stratified, the location of the return vent had a substantial impact on the measured concentrations; locating the return at the floor creates a dead-end volume at the top half (breathing zone) of the room where aerosols accumulate, whereas positioning the return on the ceiling offer the most efficient mode for removing contaminants. The deposition was an important sink for airborne particulates, and deposition observed on the walls and ceiling was higher than anticipated. There are novel comparisons between the deposition rates and measured friction velocities in the room to attempt to qualify the relative roles of turbulence, gravity, and Brownian deposition mechanisms; however, most of the deposition could be attributed to electrostatic effects. The findings in this study can have serious ramifications for developing HVAC designs that aim to minimize the risk of indoor disease transmission.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106647"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632308","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 : 2025-09-01Epub Date: 2025-06-22DOI: 10.1016/j.jaerosci.2025.106613
Sylvain Mailler , Sotirios Mallios
We propose a new method for calculating the settling speed of aerosol particles with prolate shape in the atmosphere. This method takes into account the known theoretical results on the speed–force relationships for prolate spheroids moving in a fluid, and the results in Mallios et al. (2021) regarding the orientation of prolate particles settling in the atmosphere. Unlike other studies, we focus not on the resistance problem (calculating the aerodynamic force as a function of speed) but on the mobility problem (calculate terminal velocity as a function of the external force). The result of this approach is a set of equations that permit to directly calculate the settling speed of a prolate particle in the atmosphere as a function of its shape and characteristics, which is a very important quantity in atmospheric science since the settling speed of a falling particle is a key factor to determine its lifetime in the atmosphere. With this approach, we show that the settling speed is reduced by up to 20% for particles with aspect ratio 4 compared to same-volume spheres. We compare the results of the present study to CFD results of Sanjeevi et al. (2022) and to laboratory measurements of Bhowmick et al. (2024), the latter comparison showing that the estimates for settling speed from our method is within compared to the measured value. Finally, since calculating the terminal speed of settling particles is an important issue in atmospheric modeling, we provide a Fortran module implementing the method described in the present study.
提出了一种计算长形气溶胶粒子在大气中沉降速度的新方法。该方法考虑了关于在流体中运动的长形球体的速度-力关系的已知理论结果，以及Mallios等人（2021）关于在大气中沉降的长形颗粒方向的结果。与其他研究不同，我们关注的不是阻力问题（计算作为速度函数的气动力），而是机动性问题（计算作为外力函数的终端速度）。这种方法的结果是一组方程，可以直接计算出一个长波粒子在大气中的沉降速度作为其形状和特性的函数，这是大气科学中一个非常重要的量，因为下落粒子的沉降速度是决定其在大气中寿命的关键因素。通过这种方法，我们发现与相同体积的球体相比，长径比为4的颗粒的沉降速度降低了20%。我们将本研究的结果与Sanjeevi et al.（2022）的CFD结果以及Bhowmick et al.（2024）的实验室测量结果进行了比较，后者的比较表明，我们的方法估计的沉降速度与实测值相比在±5%以内。最后，由于计算沉降粒子的终端速度是大气模拟中的一个重要问题，我们提供了一个Fortran模块来实现本研究中描述的方法。
{"title":"A direct and theoretically consistent method for the calculation of the settling speed of prolate spheroidal particles in the atmosphere","authors":"Sylvain Mailler , Sotirios Mallios","doi":"10.1016/j.jaerosci.2025.106613","DOIUrl":"10.1016/j.jaerosci.2025.106613","url":null,"abstract":"<div><div>We propose a new method for calculating the settling speed of aerosol particles with prolate shape in the atmosphere. This method takes into account the known theoretical results on the speed–force relationships for prolate spheroids moving in a fluid, and the results in Mallios et al. (2021) regarding the orientation of prolate particles settling in the atmosphere. Unlike other studies, we focus not on the resistance problem (calculating the aerodynamic force as a function of speed) but on the mobility problem (calculate terminal velocity as a function of the external force). The result of this approach is a set of equations that permit to directly calculate the settling speed of a prolate particle in the atmosphere as a function of its shape and characteristics, which is a very important quantity in atmospheric science since the settling speed of a falling particle is a key factor to determine its lifetime in the atmosphere. With this approach, we show that the settling speed is reduced by up to 20% for particles with aspect ratio 4 compared to same-volume spheres. We compare the results of the present study to CFD results of Sanjeevi et al. (2022) and to laboratory measurements of Bhowmick et al. (2024), the latter comparison showing that the estimates for settling speed from our method is within <span><math><mrow><mo>±</mo><mn>5</mn><mtext>%</mtext></mrow></math></span> compared to the measured value. Finally, since calculating the terminal speed of settling particles is an important issue in atmospheric modeling, we provide a Fortran module implementing the method described in the present study.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106613"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144469944","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 : 2025-09-01Epub Date: 2025-06-18DOI: 10.1016/j.jaerosci.2025.106637
Horace I. Looi , Halil I. Yazici , Joel C. Corbin , Rym Mehri , Timothy A. Sipkens , Kyle J. Daun
Graphene oxide (GO) particles have a wide and growing range of applications. They may also be converted to reduced graphene oxide (rGO) particles, which are increasingly used in energy storage devices like batteries and supercapacitors. However, the downstream functionality of GO and rGO particles depends strongly on their morphology, which is highly variable depending on the synthesis process. Here, we report morphological and optical properties for GO particles in the aerosol phase. These include the mobility diameter, effective density (0.93 ± 0.06 g/cm3), mass–mobility exponent (2.97 ± 0.06), Angstrom absorption exponent (2.48 between 370 nm and 950 nm), mass absorption cross-section (0.99 ± 0.22 m2 g−1), and mass scattering cross-section. Although this study reports measurements on re-aerosolized GO powder, the demonstrated techniques and measured properties serve as a foundation for in-reactor optical diagnostics that may allow for online control of the synthesis processes enabling the ability to control and characterize the functionality of downstream particles
{"title":"Investigation of the morphology and optical properties of graphene oxide for online diagnostics","authors":"Horace I. Looi , Halil I. Yazici , Joel C. Corbin , Rym Mehri , Timothy A. Sipkens , Kyle J. Daun","doi":"10.1016/j.jaerosci.2025.106637","DOIUrl":"10.1016/j.jaerosci.2025.106637","url":null,"abstract":"<div><div>Graphene oxide (GO) particles have a wide and growing range of applications. They may also be converted to reduced graphene oxide (rGO) particles, which are increasingly used in energy storage devices like batteries and supercapacitors. However, the downstream functionality of GO and rGO particles depends strongly on their morphology, which is highly variable depending on the synthesis process. Here, we report morphological and optical properties for GO particles in the aerosol phase. These include the mobility diameter, effective density (0.93 ± 0.06 g/cm<sup>3</sup>), mass–mobility exponent (2.97 ± 0.06), Angstrom absorption exponent (2.48 between 370 nm and 950 nm), mass absorption cross-section (0.99 ± 0.22 m<sup>2</sup> g<sup>−1</sup>), and mass scattering cross-section. Although this study reports measurements on re-aerosolized GO powder, the demonstrated techniques and measured properties serve as a foundation for in-reactor optical diagnostics that may allow for online control of the synthesis processes enabling the ability to control and characterize the functionality of downstream particles</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106637"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144510885","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 : 2025-09-01Epub Date: 2025-06-28DOI: 10.1016/j.jaerosci.2025.106644
Hao Wang , Fei Zhou , Lele Zhong , Fa Zhong , Xiaotong Chen , Junxia Guo , Zhenzhong Zhang
The precise characterization of the size distribution of radioactive aerosol particles is essential for environmental radiation protection. The screen diffusion battery (SDB) method has been extensively utilized for the sizing of radioactive aerosols. Nevertheless, the accurate and rapid inversion remains a significant challenge within this methodology. This study proposes several multilayer perceptron neural network models to tackle this issue. The performance and applicability of models were assessed using simulated and laboratory measurement data. Results showed that the model achieved accuracy of above 89 % at the error noise level of 10 % in the peak shape classification task. For unimodal distribution parameters, the MAPE (Mean Absolute Percentage Error) of AMD (Activity Median Diameter) and (GSD, Geometric Standard Deviation) were maintained below 1.5 % and 3.4 % at noise level of 10 %. For bimodal distribution parameters, the MAPE of all parameters were below 10.5 % at noise of 10 %. These results demonstrate the model's exceptional predictive accuracy and robust noise immunity. Comparison results in radon chamber showed a good linear correlation between AMD (obtained by the SDB system using MLP) and CMD (Count Median Diameter, measured by SMPS) with R2 of 0.888, verifying the practical measurement capability of MLP method. The prediction results can be generated almost instantaneously in the millisecond range, which presents potential for real-time and large-scale measurements. Moreover, compared with the conventional method, this MLP method does not require manual selection of initial iteration parameters and will not produce unstable oscillating solutions. These findings can significantly enhance the efficiency and reliability of radioactive aerosol size distribution analysis, supporting improved environmental monitoring, radiation risk assessment and safety protocols in nuclear facilities.
{"title":"Screen diffusion battery method for measuring the size distribution of radioactive aerosol employing multi-layer perception (MLP) neural network","authors":"Hao Wang , Fei Zhou , Lele Zhong , Fa Zhong , Xiaotong Chen , Junxia Guo , Zhenzhong Zhang","doi":"10.1016/j.jaerosci.2025.106644","DOIUrl":"10.1016/j.jaerosci.2025.106644","url":null,"abstract":"<div><div>The precise characterization of the size distribution of radioactive aerosol particles is essential for environmental radiation protection. The screen diffusion battery (SDB) method has been extensively utilized for the sizing of radioactive aerosols. Nevertheless, the accurate and rapid inversion remains a significant challenge within this methodology. This study proposes several multilayer perceptron neural network models to tackle this issue. The performance and applicability of models were assessed using simulated and laboratory measurement data. Results showed that the model achieved accuracy of above 89 % at the error noise level of 10 % in the peak shape classification task. For unimodal distribution parameters, the MAPE (Mean Absolute Percentage Error) of AMD (Activity Median Diameter) and <span><math><mrow><msub><mi>σ</mi><mi>g</mi></msub></mrow></math></span> (GSD, Geometric Standard Deviation) were maintained below 1.5 % and 3.4 % at noise level of 10 %. For bimodal distribution parameters, the MAPE of all parameters were below 10.5 % at noise of 10 %. These results demonstrate the model's exceptional predictive accuracy and robust noise immunity. Comparison results in radon chamber showed a good linear correlation between AMD (obtained by the SDB system using MLP) and CMD (Count Median Diameter, measured by SMPS) with R<sup>2</sup> of 0.888, verifying the practical measurement capability of MLP method. The prediction results can be generated almost instantaneously in the millisecond range, which presents potential for real-time and large-scale measurements. Moreover, compared with the conventional method, this MLP method does not require manual selection of initial iteration parameters and will not produce unstable oscillating solutions. These findings can significantly enhance the efficiency and reliability of radioactive aerosol size distribution analysis, supporting improved environmental monitoring, radiation risk assessment and safety protocols in nuclear facilities.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106644"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144535458","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}
Non-human primates (NHPs) are relevant models for studies of human respiratory infections due to their similar anatomy and susceptibility to human pathogens, resulting in comparable disease manifestations following exposure via aerosols or liquid instillation. An understanding of pathogen deposition in the respiratory tract (RT) of NHPs according to the method of exposure is essential for infectious disease modeling. Here, we evaluated and compared three conventional exposure systems commonly used to replicate human RT infections: liquid endotracheal instillation (IT), facemask (FM) aerosol inhalation, and head-only exposure (HOE) aerosol inhalation. Using PET/CT imaging with [18F] fluorodeoxyglucose ([18F]FDG) as the radiotracer, we quantified deposition across the upper respiratory tract (URT), lower respiratory tract (LRT), and digestive tract in anesthetized, spontaneously breathing cynomolgus macaques. A 98.0 ± 1.4 % deposited dose in the LRT was obtained with IT, whereas FM gave only 28.2 ± 6.4 % (MMAD: 3.1 μm GSD 2.2) and HOE gave 40.4 ± 19.0 % (MMAD: 1.9 μm GSD 2.0). This variability of deposition rates highlights the need for precise metrology tools. The homogeneity of lung deposition was improved and ratio between peripheral deposition/central deposition (P/C ratio) were higher with FM, and particularly with the HOE device, than with IT. An in vivo study of macaques inhaling Bacillus atrophaeus spore suspensions tracked with [18F]FDG revealed a correlation between radioactivity and spore concentration in respiratory samples (nasal/tracheal swabs, bronchoalveolar lavage) after inhalation. In conclusion, pathogen exposure systems significantly affect dose deposition and distribution within NHP airways which may thus impact vaccines and therapeutics efficacy trial in challenge models. PET/CT imaging provides a robust tool for monitoring and controlling exposure to respiratory pathogens, decreasing the number of animals required for studies through precise dose control and tissue targeting. Exposure systems should be tailored to inhalation scenarios such as close contact or accumulated aerosol exposure, to reproduce improve relevance of preclinical models.
{"title":"Positron emission tomography-based comparison of methods for exposing macaques to respiratory pathogens","authors":"Benoît Delache , Anaïs-Rachel Garnier , Cécile Herate , Francis Relouzat , Pierre Lê-Bury , Julien Lemaitre , Asma Berriche , Quentin Sconosciuti , Eleana Navarre , Noémie Verguet , Justina Creppy , Olivier Gorgé , Jean-Nicolas Tournier , Frédéric Ducancel , Laurent Vecellio , Roger Le Grand , Thibaut Naninck","doi":"10.1016/j.jaerosci.2025.106646","DOIUrl":"10.1016/j.jaerosci.2025.106646","url":null,"abstract":"<div><div>Non-human primates (NHPs) are relevant models for studies of human respiratory infections due to their similar anatomy and susceptibility to human pathogens, resulting in comparable disease manifestations following exposure via aerosols or liquid instillation. An understanding of pathogen deposition in the respiratory tract (RT) of NHPs according to the method of exposure is essential for infectious disease modeling. Here, we evaluated and compared three conventional exposure systems commonly used to replicate human RT infections: liquid endotracheal instillation (IT), facemask (FM) aerosol inhalation, and head-only exposure (HOE) aerosol inhalation. Using PET/CT imaging with [<sup>18</sup>F] fluorodeoxyglucose ([<sup>18</sup>F]FDG) as the radiotracer, we quantified deposition across the upper respiratory tract (URT), lower respiratory tract (LRT), and digestive tract in anesthetized, spontaneously breathing cynomolgus macaques. A 98.0 ± 1.4 % deposited dose in the LRT was obtained with IT, whereas FM gave only 28.2 ± 6.4 % (MMAD: 3.1 μm GSD 2.2) and HOE gave 40.4 ± 19.0 % (MMAD: 1.9 μm GSD 2.0). This variability of deposition rates highlights the need for precise metrology tools. The homogeneity of lung deposition was improved and ratio between peripheral deposition/central deposition (P/C ratio) were higher with FM, and particularly with the HOE device, than with IT. An <em>in vivo</em> study of macaques inhaling <em>Bacillus atrophaeus</em> spore suspensions tracked with [<sup>18</sup>F]FDG revealed a correlation between radioactivity and spore concentration in respiratory samples (nasal/tracheal swabs, bronchoalveolar lavage) after inhalation. In conclusion, pathogen exposure systems significantly affect dose deposition and distribution within NHP airways which may thus impact vaccines and therapeutics efficacy trial in challenge models. PET/CT imaging provides a robust tool for monitoring and controlling exposure to respiratory pathogens, decreasing the number of animals required for studies through precise dose control and tissue targeting. Exposure systems should be tailored to inhalation scenarios such as close contact or accumulated aerosol exposure, to reproduce improve relevance of preclinical models.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106646"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614538","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 : 2025-09-01Epub Date: 2025-06-10DOI: 10.1016/j.jaerosci.2025.106633
Taline Canto Tristão , Mariana Abou Mourad Ferreira , Pedro Sousa de Almeida Júnior , Luiz Guilherme Schmidt Castellani , Manuela Negrelli Brunetti , Edward C. Jones-López , Kevin P. Fennelly , Michael R. Barer , Carlos Henrique Fantecelle , Saulo Almeida Morellato , David Jamil Hadad , Jerrold J. Ellner , Reynaldo Dietze , Moisés Palaci
Tuberculosis (TB) is an ancient disease transmitted through aerosols frequently generated by coughing and it is still unknown whether there is variability in cough aerosol output throughout the day and whether this may impact patients’ infectivity categorization. To study the dynamic of infectious aerosols generated by cough, we conducted a cross-sectional study on pulmonary TB patients (n = 16) who had their cough-generated aerosols sampled twice daily for two consecutive days for the Cough Aerosol Sampling System (CASS) assay. Most patients were classified as Variable Low Producers and Variable High Producers (n = 10; 62.5 %), followed by Negative Producers (n = 4; 25 %) and Consistent Producers (n = 2; 12.5 %). Additionally, most recovered bacilli (88.7 %) within a respiratory aerosol size range. Although the time of collection did not appear to impact on aerosol infectivity, performing CASS with multiple samples allowed for more accurate detection and distinction among aerosol producers.
{"title":"Dynamic of infectious aerosols generated by cough from patients with pulmonary tuberculosis","authors":"Taline Canto Tristão , Mariana Abou Mourad Ferreira , Pedro Sousa de Almeida Júnior , Luiz Guilherme Schmidt Castellani , Manuela Negrelli Brunetti , Edward C. Jones-López , Kevin P. Fennelly , Michael R. Barer , Carlos Henrique Fantecelle , Saulo Almeida Morellato , David Jamil Hadad , Jerrold J. Ellner , Reynaldo Dietze , Moisés Palaci","doi":"10.1016/j.jaerosci.2025.106633","DOIUrl":"10.1016/j.jaerosci.2025.106633","url":null,"abstract":"<div><div>Tuberculosis (TB) is an ancient disease transmitted through aerosols frequently generated by coughing and it is still unknown whether there is variability in cough aerosol output throughout the day and whether this may impact patients’ infectivity categorization. To study the dynamic of infectious aerosols generated by cough, we conducted a cross-sectional study on pulmonary TB patients (n = 16) who had their cough-generated aerosols sampled twice daily for two consecutive days for the Cough Aerosol Sampling System (CASS) assay. Most patients were classified as Variable Low Producers and Variable High Producers (n = 10; 62.5 %), followed by Negative Producers (n = 4; 25 %) and Consistent Producers (n = 2; 12.5 %). Additionally, most recovered bacilli (88.7 %) within a respiratory aerosol size range. Although the time of collection did not appear to impact on aerosol infectivity, performing CASS with multiple samples allowed for more accurate detection and distinction among aerosol producers.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106633"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280573","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 : 2025-09-01Epub Date: 2025-06-20DOI: 10.1016/j.jaerosci.2025.106636
Timothy A. Sipkens, Joel C. Corbin
Aerosol classifiers allow particle populations to be described in terms of mass, mobility diameter, or aerodynamic diameter distributions. When this classification is combined with a second layer of classification, a bidimensional distribution can be retrieved that provides additional insights into the distribution of aerosol properties. Bidimensional distributions are often transformed from extensive quantities related to the measurement (e.g., particle mass) to intensive ones that provide more intuitive insights of particle morphology (e.g., effective density or black-carbon mass fraction). Further, most extensive properties are highly correlated with one another (e.g., particle mass and mobility diameter). This complicates inversion, resulting in retrieved distributions that are considerably broader than the true distribution. In this work, we show that these problems can be solved using a single analysis step to compute distributions-of-interest, phrased in terms of intensive properties. This yields a direct inversion scheme that (1) avoids the need for post-processing to retrieve common distributions-of-interest; (2) reduces the correlation between the aerosol properties for which the bidimensional distribution is defined; (3) makes regularization easier and more objective; and (4) improves the minimum resolvable distribution width by up to 96 %. The approach is demonstrated using both simulated distributions (phantoms) and experimental data.
{"title":"Direct inversion for bidimensional distributions of aerosol characteristics","authors":"Timothy A. Sipkens, Joel C. Corbin","doi":"10.1016/j.jaerosci.2025.106636","DOIUrl":"10.1016/j.jaerosci.2025.106636","url":null,"abstract":"<div><div>Aerosol classifiers allow particle populations to be described in terms of mass, mobility diameter, or aerodynamic diameter distributions. When this classification is combined with a second layer of classification, a bidimensional distribution can be retrieved that provides additional insights into the distribution of aerosol properties. Bidimensional distributions are often transformed from extensive quantities related to the measurement (e.g., particle mass) to intensive ones that provide more intuitive insights of particle morphology (e.g., effective density or black-carbon mass fraction). Further, most extensive properties are highly correlated with one another (e.g., particle mass and mobility diameter). This complicates inversion, resulting in retrieved distributions that are considerably broader than the true distribution. In this work, we show that these problems can be solved using a single analysis step to compute distributions-of-interest, phrased in terms of intensive properties. This yields a <em>direct</em> inversion scheme that (1) avoids the need for post-processing to retrieve common distributions-of-interest; (2) reduces the correlation between the aerosol properties for which the bidimensional distribution is defined; (3) makes regularization easier and more objective; and (4) improves the minimum resolvable distribution width by up to 96 %. The approach is demonstrated using both simulated distributions (phantoms) and experimental data.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106636"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144492167","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 : 2025-09-01Epub Date: 2025-06-10DOI: 10.1016/j.jaerosci.2025.106626
Farnaz Khosravi , Gregory S. Lewis , Arantzazu Eiguren Fernandez , Francesco Carbone
Combustion emissions impact air pollution, and the development of advanced tools to detect and monitor increasingly smaller flame-formed aerosols is vital for implementing ever-more effective air-quality regulations and reducing the environmental impact of combustion applications. Condensation Particle Counters (CPCs) can detect both charged and neutral aerosols in very low number concentrations and are of widespread use in atmospheric metrology thanks to their relative portability, affordability, and simplicity of operation. Still, their detection efficiency is influenced by the size, charge state, and morphology of the aerosols to be detected, in addition to their composition, which influences their wettability by the condensing fluid(s). As a result, calibrations are necessary to characterize the detection efficiency of a CPC, especially for flame-formed carbonaceous aerosols smaller than 3 nm, which can have quite polydisperse composition and properties. In this study, two-component (fluid-Water) CPCs resulting from coupling a Water CPC (WCPC) with a saturator inlet operated with either n-butanol (nBA), iso-propanol (IPA), or ethanol (EtOH) are characterized for the detection of naturally charged carbonaceous aerosols formed in an incipiently sooting premixed flame. Khosravi et al. (2023) operated the saturator inlet with Diethylene Glycol (DEG) and showed that the concurrent supersaturations of water and DEG (i.e., any fluid with Le > 1) established in the DEG-WCPC (i.e., any fluid-WCPC) enhance the detection of materials smaller than 3 nm. The results herein demonstrate that the nBA-WCPC, the IPA-WCPC, and the EtOH-WCP have not only comparable or even superior (surely in the case of the IPA-WCPC) performances in terms of the minimum sizes detectable with 50 % efficiency but also the advantages of minimal needs for cleaning the optics and composition-independent and steeper profiles of the size-dependent detection efficiency compared to the DEG-WCPC. This is the case even though the lengths of the CPC stages have not been optimized yet for using the tested C2-C4 alcohols in the saturator inlet. In particular, the use of EtOH as a performant CPC working fluid is the first-of-a-kind, with the EtOH-WCPC already achieving the steepest detection efficiency profiles, a feature attractive for studies requiring sizing resolution, and having the largest room for performance improvements.
燃烧排放影响空气污染，开发先进的工具来检测和监测越来越小的火焰形成的气溶胶，对于实施更有效的空气质量法规和减少燃烧应用对环境的影响至关重要。冷凝粒子计数器（cpc）可以检测极低数量浓度的带电和中性气溶胶，由于其相对便携性，可负担性和操作简单，在大气计量中广泛使用。尽管如此，它们的检测效率受到要检测的气溶胶的大小、电荷状态和形态的影响，以及它们的组成，这影响了它们被冷凝流体润湿性。因此，有必要进行校准，以表征CPC的检测效率，特别是对于小于3nm的火焰形成的碳质气溶胶，这些气溶胶可能具有相当多的分散成分和性质。在本研究中，双组分（流体-水）CPC由水CPC （WCPC）与饱和器入口耦合而成，该入口由正丁醇（nBA）、异丙醇（IPA）或乙醇（EtOH）操作，用于检测在早期煤烟预混火焰中形成的自然带电的碳质气溶胶。Khosravi et al.（2023）用二甘醇（DEG）操作饱和器入口，并表明水和DEG（即任何含有Le >的流体）同时过饱和；1)建立的DEG-WCPC（即任何流体- wcpc）增强了对小于3nm的物质的检测。本文的研究结果表明，nBA-WCPC、IPA-WCPC和EtOH-WCP不仅在以50%的效率检测最小尺寸方面具有相当甚至更好的性能（当然在IPA-WCPC的情况下），而且与DEG-WCPC相比，清洗光学元件的需求最少，与成分无关，与尺寸相关的检测效率曲线更陡峭。即使在饱和器进口中使用测试的C2-C4醇，CPC级的长度尚未优化，情况也是如此。特别值得一提的是，EtOH作为高性能CPC工作液的使用是同类中第一次，EtOH- wcpc已经实现了最陡的检测效率曲线，这一特性对需要尺寸分辨率的研究具有吸引力，并且具有最大的性能改进空间。
{"title":"Concurrent supersaturation of C2-C4 alcohols and water in a Condensation Particle Counter (CPC) to measure naturally charged flame-formed carbonaceous aerosols smaller than 3 nm","authors":"Farnaz Khosravi , Gregory S. Lewis , Arantzazu Eiguren Fernandez , Francesco Carbone","doi":"10.1016/j.jaerosci.2025.106626","DOIUrl":"10.1016/j.jaerosci.2025.106626","url":null,"abstract":"<div><div>Combustion emissions impact air pollution, and the development of advanced tools to detect and monitor increasingly smaller flame-formed aerosols is vital for implementing ever-more effective air-quality regulations and reducing the environmental impact of combustion applications. Condensation Particle Counters (CPCs) can detect both charged and neutral aerosols in very low number concentrations and are of widespread use in atmospheric metrology thanks to their relative portability, affordability, and simplicity of operation. Still, their detection efficiency is influenced by the size, charge state, and morphology of the aerosols to be detected, in addition to their composition, which influences their wettability by the condensing fluid(s). As a result, calibrations are necessary to characterize the detection efficiency of a CPC, especially for flame-formed carbonaceous aerosols smaller than 3 nm, which can have quite polydisperse composition and properties. In this study, two-component (<em>fluid</em>-Water) CPCs resulting from coupling a Water CPC (WCPC) with a <em>saturator</em> inlet operated with either n-butanol (nBA), iso-propanol (IPA), or ethanol (EtOH) are characterized for the detection of naturally charged carbonaceous aerosols formed in an incipiently sooting premixed flame. Khosravi et al. (2023) operated the <em>saturator</em> inlet with Diethylene Glycol (DEG) and showed that the concurrent supersaturations of water and DEG (i.e., any <em>fluid</em> with <em>Le</em> > 1) established in the DEG-WCPC (i.e., any <em>fluid</em>-WCPC) enhance the detection of materials smaller than 3 nm. The results herein demonstrate that the nBA-WCPC, the IPA-WCPC, and the EtOH-WCP have not only comparable or even superior (surely in the case of the IPA-WCPC) performances in terms of the minimum sizes detectable with 50 % efficiency but also the advantages of minimal needs for cleaning the optics and composition-independent and steeper profiles of the size-dependent detection efficiency compared to the DEG-WCPC. This is the case even though the lengths of the CPC stages have not been optimized yet for using the tested C2-C4 alcohols in the <em>saturator</em> inlet. In particular, the use of EtOH as a performant CPC working fluid is the first-of-a-kind, with the EtOH-WCPC already achieving the steepest detection efficiency profiles, a feature attractive for studies requiring sizing resolution, and having the largest room for performance improvements.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106626"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330601","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 : 2025-09-01Epub Date: 2025-06-03DOI: 10.1016/j.jaerosci.2025.106623
Yueyang Li , Michel Attoui , Yiliang Liu , Qiwen Sun , Qing Li , Runlong Cai , Lin Wang
Accurate prediction of aerosol charge distribution is crucial for aerosol size distribution measurements using electrical mobility spectrometers. The charge distribution of widely used bipolar diffusion aerosol charging is affected by the electrical mobility and mass of ions. In this study, we developed and evaluated a concentric cylindrical double dielectric barrier discharge (DBD) bipolar charger, and investigated the impact of measurement conditions on electrical mobility and mass of charging ions. The size-resolved chemical composition of ions produced by the DBD charger was analyzed using a high-resolution half-mini differential mobility analyzer coupled to an atmospheric pressure interface time-of-flight mass spectrometer. The effects of the discharge gas, carrier gas and relative humidity (RH) on ion properties were evaluated. Our results show that both discharge gas and carrier gas influenced the chemical composition of ions. The detected high-abundance ions were mainly originated from impurities in the carrier and discharge gases, or compounds used when manufacturing the system components. The ion mobility distribution varied with the type of carrier gas and its relative humidity, but was not sensitive to discharge gas or its flowrate. The measured charge distribution using the DBD charger was in a good agreement with Wiedensohler's approximation (Wiedensohler, 1988), and the theoretically predicted charge distribution, calculated from the measured ion properties, was also consistent with the experimental results. Only minor variations with a relative uncertainty of 12.1% and 9.5% for positive and negative particles, respectively, in singly charged particle fractions were expected among different measurement conditions. Despite a higher uncertainty likely introduced by using ambient air as the carrier gas, our work indicates that the newly developed DBD charger has the potential to be used as a bipolar charger under typical laboratory and ambient measurement conditions.
{"title":"Size-resolved chemical composition analysis of ions produced by a dielectric barrier discharge bipolar charger","authors":"Yueyang Li , Michel Attoui , Yiliang Liu , Qiwen Sun , Qing Li , Runlong Cai , Lin Wang","doi":"10.1016/j.jaerosci.2025.106623","DOIUrl":"10.1016/j.jaerosci.2025.106623","url":null,"abstract":"<div><div>Accurate prediction of aerosol charge distribution is crucial for aerosol size distribution measurements using electrical mobility spectrometers. The charge distribution of widely used bipolar diffusion aerosol charging is affected by the electrical mobility and mass of ions. In this study, we developed and evaluated a concentric cylindrical double dielectric barrier discharge (DBD) bipolar charger, and investigated the impact of measurement conditions on electrical mobility and mass of charging ions. The size-resolved chemical composition of ions produced by the DBD charger was analyzed using a high-resolution half-mini differential mobility analyzer coupled to an atmospheric pressure interface time-of-flight mass spectrometer. The effects of the discharge gas, carrier gas and relative humidity (RH) on ion properties were evaluated. Our results show that both discharge gas and carrier gas influenced the chemical composition of ions. The detected high-abundance ions were mainly originated from impurities in the carrier and discharge gases, or compounds used when manufacturing the system components. The ion mobility distribution varied with the type of carrier gas and its relative humidity, but was not sensitive to discharge gas or its flowrate. The measured charge distribution using the DBD charger was in a good agreement with Wiedensohler's approximation (Wiedensohler, 1988), and the theoretically predicted charge distribution, calculated from the measured ion properties, was also consistent with the experimental results. Only minor variations with a relative uncertainty of 12.1% and 9.5% for positive and negative particles, respectively, in singly charged particle fractions were expected among different measurement conditions. Despite a higher uncertainty likely introduced by using ambient air as the carrier gas, our work indicates that the newly developed DBD charger has the potential to be used as a bipolar charger under typical laboratory and ambient measurement conditions.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106623"},"PeriodicalIF":3.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231580","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}
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