Pub Date : 2025-08-06DOI: 10.1016/j.jaerosci.2025.106665
Nichakran Vichayarom , Kata Jaruwongrangsee , Panich Intra , Thi-Cuc Le , Chuen-Jinn Tsai , John Morris , Perapong Tekasakul , Racha Dejchanchaiwong
To improve ultrafine particle (UFPs) collection and thus measurement of mass concentrations, we developed a sensitive quartz crystal microbalance (QCM), capable of measuring mass at the nanogram level: an electrostatic force was applied to draw particles to a target position, so that all charged particles in the collection zone were measured. In its design, the COMSOL Multiphysics simulation was used to investigate airflow, electric field strength distribution, particle trajectory, particle deposition position, and collection efficiency within the collection zone inside the QCM detector. The airflow pattern exhibited dominant streamlines that flowed vertically through the nozzles and then horizontally along the QCM plate. This configuration directed UFPs along the streamlines, enhancing their deposition onto the plate. The multi-nozzle design also provided a uniform electric field throughout the collection zone, with average electric field strengths over the QCM surface ranged from 399.9 kV/m to 666.4 kV/m. Increasing the applied voltage and particle charge enhanced both velocity and collection efficiency. Varying particle size was also examined, showing that smaller particles were more responsive to electrostatic forces, as indicated by higher particle terminal velocities. The simulated collection efficiency for 30–100 nm particles agreed strongly with predictions from the Deutsch-Anderson equation, where the percentage error between experimental and theoretical results ranged from 4.1 % to 18.3 %. This confirmed that electrostatic force played a significant role in improving the collection efficiency of QCM detectors for UFPs.
{"title":"Numerical investigation of enhanced ultrafine particle collection in quartz crystal microbalance with electric fields","authors":"Nichakran Vichayarom , Kata Jaruwongrangsee , Panich Intra , Thi-Cuc Le , Chuen-Jinn Tsai , John Morris , Perapong Tekasakul , Racha Dejchanchaiwong","doi":"10.1016/j.jaerosci.2025.106665","DOIUrl":"10.1016/j.jaerosci.2025.106665","url":null,"abstract":"<div><div>To improve ultrafine particle (UFPs) collection and thus measurement of mass concentrations, we developed a sensitive quartz crystal microbalance (QCM), capable of measuring mass at the nanogram level: an electrostatic force was applied to draw particles to a target position, so that all charged particles in the collection zone were measured. In its design, the COMSOL Multiphysics simulation was used to investigate airflow, electric field strength distribution, particle trajectory, particle deposition position, and collection efficiency within the collection zone inside the QCM detector. The airflow pattern exhibited dominant streamlines that flowed vertically through the nozzles and then horizontally along the QCM plate. This configuration directed UFPs along the streamlines, enhancing their deposition onto the plate. The multi-nozzle design also provided a uniform electric field throughout the collection zone, with average electric field strengths over the QCM surface ranged from 399.9 kV/m to 666.4 kV/m. Increasing the applied voltage and particle charge enhanced both velocity and collection efficiency. Varying particle size was also examined, showing that smaller particles were more responsive to electrostatic forces, as indicated by higher particle terminal velocities. The simulated collection efficiency for 30–100 nm particles agreed strongly with predictions from the Deutsch-Anderson equation, where the percentage error between experimental and theoretical results ranged from 4.1 % to 18.3 %. This confirmed that electrostatic force played a significant role in improving the collection efficiency of QCM detectors for UFPs.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"190 ","pages":"Article 106665"},"PeriodicalIF":2.9,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828083","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 : 2025-08-05DOI: 10.1016/j.jaerosci.2025.106662
M. Attoui , J. Fernandez de la Mora , F. Carbone
The variable saturation condensation particle sizer (VSCPS) of Gallar et al. (2006) determines a condensation (Kelvin) diameter by scanning over the saturation ratio at fixed instrument temperatures, sample flow rate, and total sheath flow rate. This is achieved by mixing a saturated and a dry stream while scanning over the dry/wet flow rate ratio. Previous studies with this VSCPS have used n-butanol and Fluorinert™ FC-43. A slightly modified form of the instrument is tested here with polyethylene glycol particles 3–9 nm in diameter and four working fluids: Propylene Glycol (PG), 2-propanol, ethanol, and methanol. The latter three give steep activation curves (FWHM∼ 2 %). However, this steepness depends on the quality of the bipolar electrospray used to produce monodisperse seed particles. Nevertheless, methanol yields the narrowest activation curves at all sizes studied, especially the smallest ones. All liquids tested except methanol show a widening of the activation curve at diminishing particle diameters, in qualitative agreement with classical heterogeneous nucleation theory with perfect wetting. The response time depends strongly on working fluid volatility (7.8 s for PG; 1.2 s for methanol), apparently due to the time required to dry the condensate film deposited on the wall of the thermal insulator separating the saturator from the condenser.
{"title":"Operation of a variable saturation condensation particle sizer with 2-propanol, ethanol, methanol, and propylene glycol: Resolution and delay time versus volatility","authors":"M. Attoui , J. Fernandez de la Mora , F. Carbone","doi":"10.1016/j.jaerosci.2025.106662","DOIUrl":"10.1016/j.jaerosci.2025.106662","url":null,"abstract":"<div><div>The variable saturation condensation particle sizer (VSCPS) of Gallar et al. (2006) determines a condensation (Kelvin) diameter by scanning over the saturation ratio at fixed instrument temperatures, sample flow rate, and total sheath flow rate. This is achieved by mixing a saturated and a dry stream while scanning over the dry/wet flow rate ratio. Previous studies with this VSCPS have used n-butanol and Fluorinert™ FC-43. A slightly modified form of the instrument is tested here with polyethylene glycol particles 3–9 nm in diameter and four working fluids: Propylene Glycol (PG), 2-propanol, ethanol, and methanol. The latter three give steep activation curves (<em>FWHM</em>∼ 2 %). However, this steepness depends on the quality of the bipolar electrospray used to produce monodisperse seed particles. Nevertheless, methanol yields the narrowest activation curves at all sizes studied, especially the smallest ones. All liquids tested except methanol show a widening of the activation curve at diminishing particle diameters, in qualitative agreement with classical heterogeneous nucleation theory with perfect wetting. The response time depends strongly on working fluid volatility (7.8 s for PG; 1.2 s for methanol), apparently due to the time required to dry the condensate film deposited on the wall of the thermal insulator separating the saturator from the condenser.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"190 ","pages":"Article 106662"},"PeriodicalIF":2.9,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144781100","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 : 2025-08-05DOI: 10.1016/j.jaerosci.2025.106664
Saima Bukhat Khan , Joel Alroe , Chris Medcraft , Emilie Sauret , Daniel Harrison , Zoran Ristovski
Spray systems play a crucial role in various industrial and environmental applications, where precise control over droplet size is critical for achieving efficiency. Despite extensive studies on primary breakup, which involves the disintegration of liquid jets or sheets into droplets, the dynamics of secondary breakup, where droplets fragment post-formation, remain less understood. In environmental applications, among various nozzles, impaction-pin nozzles have enabled the production of fine misting droplets at micron and submicron levels. One of the applications of these impaction-pin nozzles is to produce an artificial fog using high pressure seawater to shade corals, a technology under investigation within the Reef Restoration and Adaptation (RRAP) program. This study aims to model and characterise the secondary breakup dynamics in impaction-pin nozzles using a combined numerical and experimental approach. Simulations are performed using Discrete Phase Model (DPM) to model droplet dynamics and size distribution, leveraging its efficiency and accuracy for dispersed-phase tracking. The numerical model incorporated stochastic breakup, coalescence, and evaporation models within Euler-Lagrangian framework, alongside unsteady RANS modelling for gas-phase flow. Experimental validation was performed using a Scanning Electrical Mobility Sizer (SEMS) and an Aerodynamic Particle Sizer (APS), ensuring high-resolution particle size measurements particularly at micron and submicron levels. The impaction-pin nozzle (MeeFog IP-2115-08) used in this study atomised seawater droplets under controlled conditions. Both the experiment and simulations yielded similar log-normal distributions of dry particle sizes upon evaporation. The mean diameter for numerical CFD distribution was 322.4 nm with humidified distribution at 51 % of relative humidity had mean of 236.3 nm and initial dry particles at 675.1 nm, keeping the ranges within the experimental and numerical errors. The model also predicted the spatial distribution of droplets and spray characteristics with experimental visualisation, such as angle variation during spray development, which correlated well with experimental observations. This work provides valuable insights into secondary breakup dynamics and offers a validated framework for optimizing impaction-pin nozzle spray systems for applications requiring precise droplet size control.
{"title":"Secondary droplet breakup of impaction-pin nozzle: Comparison between experimental and CFD-DPM modelling","authors":"Saima Bukhat Khan , Joel Alroe , Chris Medcraft , Emilie Sauret , Daniel Harrison , Zoran Ristovski","doi":"10.1016/j.jaerosci.2025.106664","DOIUrl":"10.1016/j.jaerosci.2025.106664","url":null,"abstract":"<div><div>Spray systems play a crucial role in various industrial and environmental applications, where precise control over droplet size is critical for achieving efficiency. Despite extensive studies on primary breakup, which involves the disintegration of liquid jets or sheets into droplets, the dynamics of secondary breakup, where droplets fragment post-formation, remain less understood. In environmental applications, among various nozzles, impaction-pin nozzles have enabled the production of fine misting droplets at micron and submicron levels. One of the applications of these impaction-pin nozzles is to produce an artificial fog using high pressure seawater to shade corals, a technology under investigation within the Reef Restoration and Adaptation (RRAP) program. This study aims to model and characterise the secondary breakup dynamics in impaction-pin nozzles using a combined numerical and experimental approach. Simulations are performed using Discrete Phase Model (DPM) to model droplet dynamics and size distribution, leveraging its efficiency and accuracy for dispersed-phase tracking. The numerical model incorporated stochastic breakup, coalescence, and evaporation models within Euler-Lagrangian framework, alongside unsteady RANS modelling for gas-phase flow. Experimental validation was performed using a Scanning Electrical Mobility Sizer (SEMS) and an Aerodynamic Particle Sizer (APS), ensuring high-resolution particle size measurements particularly at micron and submicron levels. The impaction-pin nozzle (<em>MeeFog IP-2115-08</em>) used in this study atomised seawater droplets under controlled conditions. Both the experiment and simulations yielded similar log-normal distributions of dry particle sizes upon evaporation. The mean diameter for numerical CFD distribution was 322.4 nm with humidified distribution at 51 % of relative humidity had mean of 236.3 nm and initial dry particles at 675.1 nm, keeping the ranges within the experimental and numerical errors. The model also predicted the spatial distribution of droplets and spray characteristics with experimental visualisation, such as angle variation during spray development, which correlated well with experimental observations. This work provides valuable insights into secondary breakup dynamics and offers a validated framework for optimizing impaction-pin nozzle spray systems for applications requiring precise droplet size control.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"190 ","pages":"Article 106664"},"PeriodicalIF":2.9,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780996","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 : 2025-07-30DOI: 10.1016/j.jaerosci.2025.106648
K.S. Moreira , L.P. Di Bonito , K. Glanzer , A. Carrasco-Munoz , F. Di Natale , J.P.M. Marques , P.A. Gabriel , M.E. Oliveira , L.L.F. Agostinho
Electrohydrodynamic Atomization (EHDA), often called electrospray, is a way to disintegrate a liquid into droplets by exposing it to a strong electric field. In this technique, it is possible to set different spraying modes by changing the physicochemical properties of the atomized liquids and the configuration of the experimental setup. There are four known modes in EHDA: dripping, intermittent, cone-jet, and multi-jet mode. Controlling the electrospray mode is crucial, as each mode has distinct operating flow rates, potential characteristics, and droplet properties. Current classifications rely on optical verification, which is often impractical in explosive or confined environments. In this work, a real-time EHDA mode classification system based on Verdoold et al. (2014) approach was developed. The system uses the spray electric current as the main classification parameter and uses several threads working in parallel to optimize its computational performance. The first results have shown a good performance of the system in classifying EHDA modes for various liquids. This work presents the first EHDA mode classification algorithm capable of automatically classifying three EHDA modes and detecting corona discharge. This new system has significant potential for implementation in various industrial applications.
电流体动力雾化（EHDA），通常被称为电喷雾，是一种通过将液体暴露在强电场中将其分解成液滴的方法。在这种技术中，可以通过改变雾化液体的物理化学性质和实验装置的配置来设置不同的喷涂模式。有四种已知的EHDA模式：滴，间歇，锥形射流和多射流模式。控制电喷雾模式是至关重要的，因为每种模式都有不同的操作流速、电位特性和液滴特性。目前的分类依靠光学验证，这在爆炸性或密闭环境中通常是不切实际的。本文基于Verdoold et al.（2014）的方法，开发了一个实时EHDA模式分类系统。该系统以喷雾电流为主要分类参数，采用多线程并行工作优化计算性能。初步结果表明，该系统对各种液体的EHDA模式进行了较好的分类。本文提出了首个能够自动分类三种EHDA模式并检测电晕放电的EHDA模式分类算法。这种新系统在各种工业应用中具有重大的实施潜力。
{"title":"Electric current based automatic classification and operation of EHDA modes","authors":"K.S. Moreira , L.P. Di Bonito , K. Glanzer , A. Carrasco-Munoz , F. Di Natale , J.P.M. Marques , P.A. Gabriel , M.E. Oliveira , L.L.F. Agostinho","doi":"10.1016/j.jaerosci.2025.106648","DOIUrl":"10.1016/j.jaerosci.2025.106648","url":null,"abstract":"<div><div>Electrohydrodynamic Atomization (EHDA), often called electrospray, is a way to disintegrate a liquid into droplets by exposing it to a strong electric field. In this technique, it is possible to set different spraying modes by changing the physicochemical properties of the atomized liquids and the configuration of the experimental setup. There are four known modes in EHDA: dripping, intermittent, cone-jet, and multi-jet mode. Controlling the electrospray mode is crucial, as each mode has distinct operating flow rates, potential characteristics, and droplet properties. Current classifications rely on optical verification, which is often impractical in explosive or confined environments. In this work, a real-time EHDA mode classification system based on Verdoold et al. (2014) approach was developed. The system uses the spray electric current as the main classification parameter and uses several threads working in parallel to optimize its computational performance. The first results have shown a good performance of the system in classifying EHDA modes for various liquids. This work presents the first EHDA mode classification algorithm capable of automatically classifying three EHDA modes and detecting corona discharge. This new system has significant potential for implementation in various industrial applications.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"190 ","pages":"Article 106648"},"PeriodicalIF":2.9,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757319","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 : 2025-07-10DOI: 10.1016/j.jaerosci.2025.106642
S. Sankurantripati , F. Duchaine , N. Francois , S. Marshall , P. Nekolny
In response to the recent COVID-19 pandemic, Ultraviolet (UV) air purifiers have emerged as a recommended mitigation strategy to deactivate airborne viruses and reduce infection spread within enclosed spaces. This paper focuses on developing a high fidelity computational methodology to investigate the efficacy of such devices. Large Eddy Simulations are used to resolve the turbulent flow inside the purifier with 2 UV lamps activated for specified operating conditions. A fully coupled, or two-way coupling approach, is compared with a computationally efficient one-way coupling method. Once the Eulerian flow reaches statistical convergence, time-averaged velocity and temperature distributions are extracted and provided to an Eulerian–Lagrangian framework to examine the turbulent dispersion of virus-laden droplets based on a frozen flow approach. These simulations incorporate an evaporation model for virus-laden droplets, highlighting the importance of accounting for this physical phenomenon. The majority of droplets exiting the purifier are identified as droplet nuclei containing non-volatile matter and virus copies. The survival rate of these expelled virus-laden droplets is determined using a UV radiation disinfection solver, developed and validated based on existing experimental studies. The resulting inactivation rate of the UV air purifier reaches 99%, highlighting its potential as an effective mitigation strategy.
{"title":"Large eddy simulations to investigate airborne virus inactivation using a ultraviolet air purifier with Lagrangian tracking","authors":"S. Sankurantripati , F. Duchaine , N. Francois , S. Marshall , P. Nekolny","doi":"10.1016/j.jaerosci.2025.106642","DOIUrl":"10.1016/j.jaerosci.2025.106642","url":null,"abstract":"<div><div>In response to the recent COVID-19 pandemic, Ultraviolet (UV) air purifiers have emerged as a recommended mitigation strategy to deactivate airborne viruses and reduce infection spread within enclosed spaces. This paper focuses on developing a high fidelity computational methodology to investigate the efficacy of such devices. Large Eddy Simulations are used to resolve the turbulent flow inside the purifier with 2 UV lamps activated for specified operating conditions. A fully coupled, or two-way coupling approach, is compared with a computationally efficient one-way coupling method. Once the Eulerian flow reaches statistical convergence, time-averaged velocity and temperature distributions are extracted and provided to an Eulerian–Lagrangian framework to examine the turbulent dispersion of virus-laden droplets based on a frozen flow approach. These simulations incorporate an evaporation model for virus-laden droplets, highlighting the importance of accounting for this physical phenomenon. The majority of droplets exiting the purifier are identified as droplet nuclei containing non-volatile matter and virus copies. The survival rate of these expelled virus-laden droplets is determined using a UV radiation disinfection solver, developed and validated based on existing experimental studies. The resulting inactivation rate of the UV air purifier reaches 99%, highlighting its potential as an effective mitigation strategy.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106642"},"PeriodicalIF":3.9,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662954","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 : 2025-07-05DOI: 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":"2025-07-05","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}
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":"2025-07-05","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 : 2025-07-05DOI: 10.1016/j.jaerosci.2025.106643
Liam White, Edward P. DeMauro, German Drazer
In this study, trap impactors are used to collect polydisperse liquid droplets and are compared to the efficiency predicted by a conventional inertial impactor with excellent agreement. Polydisperse droplets are atomized and vary from to in diameter. Droplets are characterized after the impactor nozzle with an optical particle sizer to determine the size distribution and the corresponding distribution of Stokes numbers (St) at the tested flow rates. The trap ratio is defined as the difference between the trap and nozzle diameters divided by the total depth of the trap. To characterize the trap geometry, multiple traps are tested with varying trap ratios and demonstrate that decreasing the trap ratio results in a reduction in trap efficiency and an increase in wall losses. Specifically, a trap ratio of 1.00 resulted in a maximum trap efficiency of 94%, whereas a trap ratio of 0.27 had a maximum trap efficiency of 31%. Trap impactor design recommendations are made to maximize droplet collection inside the trap by increasing the trap ratio.
{"title":"The influence of geometry on particle capture efficiency in trap impactors","authors":"Liam White, Edward P. DeMauro, German Drazer","doi":"10.1016/j.jaerosci.2025.106643","DOIUrl":"10.1016/j.jaerosci.2025.106643","url":null,"abstract":"<div><div>In this study, trap impactors are used to collect polydisperse liquid droplets and are compared to the efficiency predicted by a conventional inertial impactor with excellent agreement. Polydisperse droplets are atomized and vary from <span><math><mrow><mn>0</mn><mo>.</mo><mn>3</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> to <span><math><mrow><mn>10</mn><mo>.</mo><mn>5</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> in diameter. Droplets are characterized after the impactor nozzle with an optical particle sizer to determine the size distribution and the corresponding distribution of Stokes numbers (St) at the tested flow rates. The trap ratio is defined as the difference between the trap and nozzle diameters divided by the total depth of the trap. To characterize the trap geometry, multiple traps are tested with varying trap ratios and demonstrate that decreasing the trap ratio results in a reduction in trap efficiency and an increase in wall losses. Specifically, a trap ratio of 1.00 resulted in a maximum trap efficiency of 94%, whereas a trap ratio of 0.27 had a maximum trap efficiency of 31%. Trap impactor design recommendations are made to maximize droplet collection inside the trap by increasing the trap ratio.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106643"},"PeriodicalIF":3.9,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580684","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 : 2025-07-02DOI: 10.1016/j.jaerosci.2025.106638
Ivo Neefjes , Bernhard Reischl , Huan Yang
The formation of aerosol particles from the vapor phase is a common process in both natural and industrial systems, where bimolecular collisions drive the very first step of the phase transition. Widely used analytical models, such as the non-interacting hard-sphere (NHS) and central field (CF) models, offer fast and straightforward predictions for bimolecular collision rate coefficients. However, their accuracy varies depending on the interaction strength between the collision partners. The NHS model neglects long-range forces, leading to underperformance in strongly interacting systems, while the CF model assumes point-like particles, reducing its reliability in weakly interacting systems. The recently developed interacting hard-sphere (IHS) model (Yang et al., 2023) addresses these limitations by incorporating both long-range interactions and the finite sizes of the colliding species. Despite the widespread use of these models, there is limited guidance on their applicability across different systems. In this work, we systematically evaluated the NHS, CF, and IHS models and propose a practical rule of thumb for selecting the most appropriate model. We applied this rule of thumb to a range of collision systems with varying interaction strengths and validated it against classical atomistic force field molecular dynamics simulations. Our findings show that the IHS model most accurately reproduces molecular dynamics-derived collision rate coefficients and smoothly converges to the NHS and CF models in the weak and strong interaction limits, respectively. Moreover, we find that the simpler CF model is sufficiently accurate for most systems at ambient conditions. This work provides practical guidance for balancing accuracy and complexity when predicting collision rate coefficients.
从气相形成气溶胶颗粒在自然和工业系统中都是一个常见的过程，其中双分子碰撞驱动了相变的第一步。广泛使用的分析模型，如非相互作用硬球（NHS）和中心场（CF）模型，提供了快速和直接的双分子碰撞率系数预测。然而，它们的准确性取决于碰撞伙伴之间的相互作用强度。NHS模型忽略了远程力，导致在强相互作用系统中表现不佳，而CF模型假设了点状粒子，降低了其在弱相互作用系统中的可靠性。最近开发的相互作用硬球（IHS）模型（Yang et al., 2023）通过结合远程相互作用和碰撞物种的有限大小来解决这些限制。尽管这些模型被广泛使用，但是关于它们在不同系统中的适用性的指导是有限的。在这项工作中，我们系统地评估了NHS、CF和IHS模型，并提出了选择最合适模型的实用经验法则。我们将这一经验法则应用于一系列具有不同相互作用强度的碰撞系统，并通过经典原子力场分子动力学模拟验证了它。我们的研究结果表明，IHS模型最准确地再现了分子动力学推导的碰撞率系数，并分别在弱和强相互作用极限上平滑地收敛于NHS和CF模型。此外，我们发现较简单的CF模型对于大多数环境条件下的系统具有足够的精度。这项工作为预测碰撞率系数时平衡精度和复杂性提供了实用的指导。
{"title":"Comparison of collision rate coefficient model predictions for different interaction strengths and temperatures","authors":"Ivo Neefjes , Bernhard Reischl , Huan Yang","doi":"10.1016/j.jaerosci.2025.106638","DOIUrl":"10.1016/j.jaerosci.2025.106638","url":null,"abstract":"<div><div>The formation of aerosol particles from the vapor phase is a common process in both natural and industrial systems, where bimolecular collisions drive the very first step of the phase transition. Widely used analytical models, such as the non-interacting hard-sphere (NHS) and central field (CF) models, offer fast and straightforward predictions for bimolecular collision rate coefficients. However, their accuracy varies depending on the interaction strength between the collision partners. The NHS model neglects long-range forces, leading to underperformance in strongly interacting systems, while the CF model assumes point-like particles, reducing its reliability in weakly interacting systems. The recently developed interacting hard-sphere (IHS) model (Yang et al., 2023) addresses these limitations by incorporating both long-range interactions and the finite sizes of the colliding species. Despite the widespread use of these models, there is limited guidance on their applicability across different systems. In this work, we systematically evaluated the NHS, CF, and IHS models and propose a practical rule of thumb for selecting the most appropriate model. We applied this rule of thumb to a range of collision systems with varying interaction strengths and validated it against classical atomistic force field molecular dynamics simulations. Our findings show that the IHS model most accurately reproduces molecular dynamics-derived collision rate coefficients and smoothly converges to the NHS and CF models in the weak and strong interaction limits, respectively. Moreover, we find that the simpler CF model is sufficiently accurate for most systems at ambient conditions. This work provides practical guidance for balancing accuracy and complexity when predicting collision rate coefficients.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106638"},"PeriodicalIF":3.9,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604229","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 : 2025-07-02DOI: 10.1016/j.jaerosci.2025.106645
Yi-Ming Lee , Thi-Cuc Le , Ying-Chang Chen , Gung-Hwa Hong , Guan-Yu Lin , Chuen-Jinn Tsai
Low-cost PM sensors are widely used for air quality monitoring, yet their performance is influenced by many factors such as particle concentration and size, particle properties, relative humidity, and temperature etc. Laboratory and field calibrations are normally needed to correct for the potential bias of sensor readings. However, the effect of ambient wind velocity on the sensor flow rate and the particle sampling efficiency is rarely explored. This study conducted a fundamental study on the impact of horizontal wind velocity on the PM2.5 and PM10 sampling efficiency of low-cost PM sensors in a wind tunnel using NaCl and dust test particles. Results indicated that as wind velocity increased (0.35–3.26 m/s), the sampling flow rate and sampling efficiency of PM2.5 and PM10 decreased for both sensors. To calibrate the effect of the wind velocity on the sampling efficiency, a theoretical prediction model was developed with predicted results in good agreement with the experimental data. To mitigate the influence of horizontal wind velocity on the bias of the sensors, a Multi-Hole Inlet Cover (MHIC) was designed for the PMSX003, and test results showed significant improvement in PM2.5 accuracy while PM10 performance was also enhanced. This study demonstrates that horizontal wind velocity and sampling flow rate are critical factors affecting PM sensor accuracy and a validated model is useful for improving measurement reliability in high-wind conditions. It is also expected that the novel MHIC developed in this work could be used to improve the accuracy of monitoring data and expand its applicability across various environmental conditions.
{"title":"Fundamental study of horizontal wind velocity effect on PM2.5 and PM10 sampling accuracy of low-Cost sensors","authors":"Yi-Ming Lee , Thi-Cuc Le , Ying-Chang Chen , Gung-Hwa Hong , Guan-Yu Lin , Chuen-Jinn Tsai","doi":"10.1016/j.jaerosci.2025.106645","DOIUrl":"10.1016/j.jaerosci.2025.106645","url":null,"abstract":"<div><div>Low-cost PM sensors are widely used for air quality monitoring, yet their performance is influenced by many factors such as particle concentration and size, particle properties, relative humidity, and temperature etc. Laboratory and field calibrations are normally needed to correct for the potential bias of sensor readings. However, the effect of ambient wind velocity on the sensor flow rate and the particle sampling efficiency is rarely explored. This study conducted a fundamental study on the impact of horizontal wind velocity on the PM<sub>2.5</sub> and PM<sub>10</sub> sampling efficiency of low-cost PM sensors in a wind tunnel using NaCl and dust test particles. Results indicated that as wind velocity increased (0.35–3.26 m/s), the sampling flow rate and sampling efficiency of PM<sub>2.5</sub> and PM<sub>10</sub> decreased for both sensors. To calibrate the effect of the wind velocity on the sampling efficiency, a theoretical prediction model was developed with predicted results in good agreement with the experimental data. To mitigate the influence of horizontal wind velocity on the bias of the sensors, a Multi-Hole Inlet Cover (MHIC) was designed for the PMSX003, and test results showed significant improvement in PM<sub>2.5</sub> accuracy while PM<sub>10</sub> performance was also enhanced. This study demonstrates that horizontal wind velocity and sampling flow rate are critical factors affecting PM sensor accuracy and a validated model is useful for improving measurement reliability in high-wind conditions. It is also expected that the novel MHIC developed in this work could be used to improve the accuracy of monitoring data and expand its applicability across various environmental conditions.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106645"},"PeriodicalIF":3.9,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549289","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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