Pub Date : 2025-06-12DOI: 10.1016/j.jaerosci.2025.106621
Felix W. Stollberger , Michael J. Gleichweit , Ruth Signorell , Alexander Bergmann
The frequency dependence of photothermal and photoacoustic signals provides information on evaporation, condensation, and heat transfer processes in aerosol particles. Performing such measurements at the single particle level increases accuracy and provides access to various particle properties. Previously, this was not possible due to the resonant acoustic signal amplification required in photoacoustics, which restricted usable modulation frequencies to a single value. In this study, we introduce the use of multi-frequency photothermal interferometry (n-PTI) on single, optically trapped particles and experimentally investigate the frequency dependence of the photothermal signal. The observed signal and its dependence on the optical and thermophysical properties of the particle and the interferometer probe beam are analyzed by an accompanying theoretical model. Our measurements prove the applicability of the presented method and indicate a stronger frequency dependence of the photothermal amplitude from single particles than previously observed in bulk measurements. Furthermore, we were able to decouple the contributions from the particle temperature and the thermal wave propagation and examine their frequency dependencies individually. Finally, we analyzed the direct influence of the particle on the measured signal and showed the potential of frequency-resolved photothermal measurements to study thermophysical parameters or optical properties at the single particle level in the Knudsen transition regime.
{"title":"Multi-frequency photothermal interferometry of single aerosol particles","authors":"Felix W. Stollberger , Michael J. Gleichweit , Ruth Signorell , Alexander Bergmann","doi":"10.1016/j.jaerosci.2025.106621","DOIUrl":"10.1016/j.jaerosci.2025.106621","url":null,"abstract":"<div><div>The frequency dependence of photothermal and photoacoustic signals provides information on evaporation, condensation, and heat transfer processes in aerosol particles. Performing such measurements at the single particle level increases accuracy and provides access to various particle properties. Previously, this was not possible due to the resonant acoustic signal amplification required in photoacoustics, which restricted usable modulation frequencies to a single value. In this study, we introduce the use of multi-frequency photothermal interferometry (n<span><math><mi>ω</mi></math></span>-PTI) on single, optically trapped particles and experimentally investigate the frequency dependence of the photothermal signal. The observed signal and its dependence on the optical and thermophysical properties of the particle and the interferometer probe beam are analyzed by an accompanying theoretical model. Our measurements prove the applicability of the presented method and indicate a stronger frequency dependence of the photothermal amplitude from single particles than previously observed in bulk measurements. Furthermore, we were able to decouple the contributions from the particle temperature and the thermal wave propagation and examine their frequency dependencies individually. Finally, we analyzed the direct influence of the particle on the measured signal and showed the potential of frequency-resolved photothermal measurements to study thermophysical parameters or optical properties at the single particle level in the Knudsen transition regime.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106621"},"PeriodicalIF":3.9,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306253","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 : 2025-06-10DOI: 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":"2025-06-10","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 : 2025-06-10DOI: 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":"2025-06-10","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 : 2025-06-06DOI: 10.1016/j.jaerosci.2025.106616
F.J. Higuera , I.G. Loscertales
Coulomb explosions of small electrospray droplets of a high conductivity solution of a nonvolatile electrolyte in a volatile solvent are assumed to be nearly instantaneous events in which the exploding droplet loses certain fractions of its volume and charge by shedding a number of offspring droplets small compared with the parent droplet. Using this assumption, and leaving out the inertia of the droplets, an Eulerian model is proposed for the space evolution of a spray of electrified droplets which may undergo successive Coulomb explosions and may also reach an ion evaporation regime in which ions are emitted from their surface by field evaporation, until the solvent is virtually depleted.
{"title":"An Eulerian model of an electrospray of a highly conducting solution with Coulomb explosions","authors":"F.J. Higuera , I.G. Loscertales","doi":"10.1016/j.jaerosci.2025.106616","DOIUrl":"10.1016/j.jaerosci.2025.106616","url":null,"abstract":"<div><div>Coulomb explosions of small electrospray droplets of a high conductivity solution of a nonvolatile electrolyte in a volatile solvent are assumed to be nearly instantaneous events in which the exploding droplet loses certain fractions of its volume and charge by shedding a number of offspring droplets small compared with the parent droplet. Using this assumption, and leaving out the inertia of the droplets, an Eulerian model is proposed for the space evolution of a spray of electrified droplets which may undergo successive Coulomb explosions and may also reach an ion evaporation regime in which ions are emitted from their surface by field evaporation, until the solvent is virtually depleted.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106616"},"PeriodicalIF":3.9,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254609","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 : 2025-06-03DOI: 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":"2025-06-03","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}
Pub Date : 2025-06-01DOI: 10.1016/j.jaerosci.2025.106624
Lorianne R. Shultz-Johnson , Benjamin T. Manard , Rachel Bergin , Dominic Piedmont , Jordan S. Stanberry , Hunter B. Andrews , Brian W. Ticknor , Mehmet Topsakal , Andrew Kiss , Gage Green , Matthew Wellons , Spencer Scott , Christopher Barrett , Simerjeet K. Gill , Shawna K. Tazik
Ceria (CeO2) particles with low to ultra-low loading of nickel dopant were produced using an aerosol-based, droplet-to-particle synthesis via an in-line calcination technique. This aerosol-based synthesis method enables the production of particles with a monodisperse size distribution. These produced and well-characterized, multi-element, ceria-based particles demonstrate a material exemplar for multi-method analytical testing. They were prepared from a cerium nitrate feedstock where low loading nickel dopant was added at target Ni/(Ni + Ce) atomic percents of 1 %, 0.1 %, and 0.01 %, using a nickel nitrate spike. This methodology proved to produce ceria particles doped with a dynamic range of low to ultra-low loadings of nickel over a 24-h period, with consistent size distribution, morphology, and composition. The successful incorporation of nickel was demonstrated with bulk and single particle inductively coupled plasma mass spectroscopy and revealed notable particle-to-particle elemental homogeneity. X-ray photoelectron spectroscopy demonstrated the presence of a high concentration of nickel dopant incorporated preferentially toward the surface of the particles, and that this dopant aided oxidation of surface Ce(III) atoms to Ce(IV). These particle test materials were then validated through X-ray absorption near edge spectroscopy, comparing the ultra-low 0.01 % Ni and low 1 % Ni-doped ceria samples. This revealed a more-reduced oxidation state of the nickel with an increase in dopant concentration. This work demonstrates a synthesis and systematic characterization scheme to produce multi-method analytical test particulates.
{"title":"Development and characterization of an aerosol-generated multi-method analytical particle test material","authors":"Lorianne R. Shultz-Johnson , Benjamin T. Manard , Rachel Bergin , Dominic Piedmont , Jordan S. Stanberry , Hunter B. Andrews , Brian W. Ticknor , Mehmet Topsakal , Andrew Kiss , Gage Green , Matthew Wellons , Spencer Scott , Christopher Barrett , Simerjeet K. Gill , Shawna K. Tazik","doi":"10.1016/j.jaerosci.2025.106624","DOIUrl":"10.1016/j.jaerosci.2025.106624","url":null,"abstract":"<div><div>Ceria (CeO<sub>2</sub>) particles with low to ultra-low loading of nickel dopant were produced using an aerosol-based, droplet-to-particle synthesis via an in-line calcination technique. This aerosol-based synthesis method enables the production of particles with a monodisperse size distribution. These produced and well-characterized, multi-element, ceria-based particles demonstrate a material exemplar for multi-method analytical testing. They were prepared from a cerium nitrate feedstock where low loading nickel dopant was added at target Ni/(Ni + Ce) atomic percents of 1 %, 0.1 %, and 0.01 %, using a nickel nitrate spike. This methodology proved to produce ceria particles doped with a dynamic range of low to ultra-low loadings of nickel over a 24-h period, with consistent size distribution, morphology, and composition. The successful incorporation of nickel was demonstrated with bulk and single particle inductively coupled plasma mass spectroscopy and revealed notable particle-to-particle elemental homogeneity. X-ray photoelectron spectroscopy demonstrated the presence of a high concentration of nickel dopant incorporated preferentially toward the surface of the particles, and that this dopant aided oxidation of surface Ce(III) atoms to Ce(IV). These particle test materials were then validated through X-ray absorption near edge spectroscopy, comparing the ultra-low 0.01 % Ni and low 1 % Ni-doped ceria samples. This revealed a more-reduced oxidation state of the nickel with an increase in dopant concentration. This work demonstrates a synthesis and systematic characterization scheme to produce multi-method analytical test particulates.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106624"},"PeriodicalIF":3.9,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242462","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 : 2025-05-29DOI: 10.1016/j.jaerosci.2025.106608
Jongmin Yoon , Seungjae Lee , Taesung Kim
With increasing demand for Virtual Metrology (VM) and Advanced Process Control (APC) in semiconductor manufacturing, the importance of in-situ quantitative monitoring of process results has grown beyond in-situ qualitative monitoring. Particle Size Distribution (PSD) analysis of nanoparticles ranging from several to hundreds of nanometers (nm) in diameter offers a possible method for the quantitative monitoring of plasma processes. However, conventional Particle Beam Mass Spectrometer (PBMS) systems designed for PSD analysis require pressures greater than hundreds of millitorrs for operation, which limits their applicability to modern semiconductor processes that require a medium vacuum. We propose a new PSD measurement scheme to perform PSD analysis for medium-vacuum processes. The hardware configuration includes a Vacuum Ultraviolet (VUV) irradiation chamber and a mass-to-charge ratio () measurement device consisting of a stacked-quadrupole-based charged particle funnel and Quadrupole Mass Analyzer (QMA). With this configuration, a PSD measurement algorithm is developed using a direct photoionization model-based Non-negative Least Squares (NNLSQ) method with gradient descent optimization. The PSD is estimated from multiple distributions measured under various VUV irradiation levels. The simulation results demonstrate that the proposed measurement scheme achieves an selection efficiency of 21% and a resolution of ± 3% for singly charged spherical Sodium Chloride (NaCl) nanoparticles at the sizes of 5–50 nm, which follow Maxwellian velocity distributions at 20 °C in the free molecular regime. Furthermore, under ideal photoionization-dominant conditions for NaCl nanoparticles with randomly assigned initial charges, peak-normalized target monodispersed PSDs with distribution change slopes ranging from 0.4 to 0.5 can be estimated in the size range of 5–50 nm, with mode errors within 5.6% and Geometric Standard Deviation (GSD) errors within 2.0%.
{"title":"Nanoparticle size distribution measurement scheme using mass-to-charge ratio measurements with Vacuum Ultraviolet irradiation in medium vacuum","authors":"Jongmin Yoon , Seungjae Lee , Taesung Kim","doi":"10.1016/j.jaerosci.2025.106608","DOIUrl":"10.1016/j.jaerosci.2025.106608","url":null,"abstract":"<div><div>With increasing demand for Virtual Metrology (VM) and Advanced Process Control (APC) in semiconductor manufacturing, the importance of in-situ quantitative monitoring of process results has grown beyond in-situ qualitative monitoring. Particle Size Distribution (PSD) analysis of nanoparticles ranging from several to hundreds of nanometers (nm) in diameter offers a possible method for the quantitative monitoring of plasma processes. However, conventional Particle Beam Mass Spectrometer (PBMS) systems designed for PSD analysis require pressures greater than hundreds of millitorrs for operation, which limits their applicability to modern semiconductor processes that require a medium vacuum. We propose a new PSD measurement scheme to perform PSD analysis for medium-vacuum processes. The hardware configuration includes a Vacuum Ultraviolet (VUV) irradiation chamber and a mass-to-charge ratio (<span><math><mrow><mi>m</mi><mo>/</mo><mi>q</mi></mrow></math></span>) measurement device consisting of a stacked-quadrupole-based charged particle funnel and Quadrupole Mass Analyzer (QMA). With this configuration, a PSD measurement algorithm is developed using a direct photoionization model-based Non-negative Least Squares (NNLSQ) method with gradient descent optimization. The PSD is estimated from multiple <span><math><mrow><mi>m</mi><mo>/</mo><mi>q</mi></mrow></math></span> distributions measured under various VUV irradiation levels. The simulation results demonstrate that the proposed <span><math><mrow><mi>m</mi><mo>/</mo><mi>q</mi></mrow></math></span> measurement scheme achieves an <span><math><mrow><mi>m</mi><mo>/</mo><mi>q</mi></mrow></math></span> selection efficiency of 21% and a resolution of ± 3% for singly charged spherical Sodium Chloride (NaCl) nanoparticles at the sizes of 5–50 nm, which follow Maxwellian velocity distributions at 20 °C in the free molecular regime. Furthermore, under ideal photoionization-dominant conditions for NaCl nanoparticles with randomly assigned initial charges, peak-normalized target monodispersed PSDs with distribution change slopes ranging from <span><math><mo>−</mo></math></span>0.4 to 0.5 <span><math><msup><mrow><mtext>nm</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> can be estimated in the size range of 5–50 nm, with mode errors within 5.6% and Geometric Standard Deviation (GSD) errors within 2.0%.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106608"},"PeriodicalIF":3.9,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144223531","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 : 2025-05-28DOI: 10.1016/j.jaerosci.2025.106618
Fabjola Bilo , Annalisa Zacco , Paola Cirelli , Filippo Marciano , Giuseppe Tomasoni , Sara Comai , Giorgio Vassena , Luca Perfetti , Antonio Gualtiero Mainardi , Silvia Mastrolembo Ventura , Angelo L.C. Ciribini , Michela Savoldi Boles , Sophie Dubacq , Maria Grazia Perrone , Laura Pini , Maria Lorenza Muiesan , Elena Pariani , Sandro Binda , Laura Pellegrinelli , Giorgio Costantino , Laura Borgese
This study demonstrates the applicability of air sampling for the detection of SARS-CoV-2 in a hospital by means of active bioaerosol samplers following a specifically designed air sampling strategy based on digital mapping of the architectural layout of the ward to minimize disruptions of health care activities and reducing operator risks. Prior to the experimental study, some model tests were conducted using the air sampler with a tunable flow rate to determine the most suitable real time polymerase chain reaction (RT-PCR) based detection method. Preliminary results showed the need to perform intensive extraction protocols combined with Real-time reverse transcription PCR (rRT-PCR), rather than conventional, to enhance sensitivity. The experimental study was conducted within the general medicine ward of Spedali Civili Hospital in Brescia during the winter of 2021/2022, a period marked by a high prevalence of COVID-19 cases using three active air sampling devices: Coriolis Compact®, Coriolis Micro®, and BioSpot GEM®. Environmental parameters, such as room size, occupancy, ventilation rates, and activities performed during sampling, and patients’ conditions were documented to contextualize the findings. The virus was detected in a few rooms with concentrations ranging from 1171 to 2225 copies/m3. These findings support the integration of routinary air sampling as tools for control and assessment of transmission risks, not only for SARS-CoV-2 but generalized to all airborne pathogens, supporting patient management and infection control in health care settings.
{"title":"Indoor air sampling strategies by active bioaerosol samplers: a case study to detect SARS-CoV-2 in hospital settings","authors":"Fabjola Bilo , Annalisa Zacco , Paola Cirelli , Filippo Marciano , Giuseppe Tomasoni , Sara Comai , Giorgio Vassena , Luca Perfetti , Antonio Gualtiero Mainardi , Silvia Mastrolembo Ventura , Angelo L.C. Ciribini , Michela Savoldi Boles , Sophie Dubacq , Maria Grazia Perrone , Laura Pini , Maria Lorenza Muiesan , Elena Pariani , Sandro Binda , Laura Pellegrinelli , Giorgio Costantino , Laura Borgese","doi":"10.1016/j.jaerosci.2025.106618","DOIUrl":"10.1016/j.jaerosci.2025.106618","url":null,"abstract":"<div><div>This study demonstrates the applicability of air sampling for the detection of SARS-CoV-2 in a hospital by means of active bioaerosol samplers following a specifically designed air sampling strategy based on digital mapping of the architectural layout of the ward to minimize disruptions of health care activities and reducing operator risks. Prior to the experimental study, some model tests were conducted using the air sampler with a tunable flow rate to determine the most suitable real time polymerase chain reaction (RT-PCR) based detection method. Preliminary results showed the need to perform intensive extraction protocols combined with Real-time reverse transcription PCR (rRT-PCR), rather than conventional, to enhance sensitivity. The experimental study was conducted within the general medicine ward of Spedali Civili Hospital in Brescia during the winter of 2021/2022, a period marked by a high prevalence of COVID-19 cases using three active air sampling devices: Coriolis Compact®, Coriolis Micro®, and BioSpot GEM®. Environmental parameters, such as room size, occupancy, ventilation rates, and activities performed during sampling, and patients’ conditions were documented to contextualize the findings. The virus was detected in a few rooms with concentrations ranging from 1171 to 2225 copies/m<sup>3</sup>. These findings support the integration of routinary air sampling as tools for control and assessment of transmission risks, not only for SARS-CoV-2 but generalized to all airborne pathogens, supporting patient management and infection control in health care settings.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106618"},"PeriodicalIF":3.9,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272234","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 : 2025-05-27DOI: 10.1016/j.jaerosci.2025.106611
Lukas Oeser , Benno Wessely , Nakul Samala , Lars Hillemann , Daniel Göhler , Jan Müller , Claudia Jahn-Wolf , Andreas Rudolph , Jens Lienig
Light scattering aerosol spectrometers (also known as optical particle counters, OPCs) are widely used for aerosol quantification. The single particle counting method, which is based on light scattering, can measure the size distribution and the number concentration of the sampled aerosol. However, this method is limited to low concentrations due to coincidence error. At higher concentrations, the particle pulses overlap and cannot be counted individually. It was recently shown that the detector signal of an optical aerosol spectrometer can also be evaluated by fluctuation analysis if the concentration is significantly higher than the coincidence limit of the device. This new mode of operation cannot yet provide a detailed size distribution but itis feasible to measure the median particle size and number concentration independently. The measurement information required for fluctuation analysis is drawn from the intensity distribution of the detector signal instead of individual pulses. Therefore, fluctuation analysis requires a certain average number of particles inside the measuring volume so that the detector output continuously leaves the baseline. Theminimum number concentration of the fluctuation analysis is around a factor of20 higher than the coincidence limit for single particle counting. Consequently, there is a concentration range where neither single particle counting, nor fluctuation analysis can be used.
This work introduces a new statistical signal analysis to bridge this gap. The new measurement method was experimentally verified using a monodisperse di-ethyl-hexyl-sebacat aerosol with a particle size range of 0.3 µm to 2.2 µm and a number concentration range of 1 104 cm−3 to 2 105 cm−3. An accuracy of 2 % with respect to median particle size and 5 % with respect to number concentration was achieved. The new method finally closes the gap between single particle counting and fluctuation analysis, enabling light scattering aerosol spectrometers to quantify aerosols at any given concentration.
{"title":"Statistical signal analysis for optical aerosol spectrometers: Closing the gap between single particle counting and signal fluctuation analysis","authors":"Lukas Oeser , Benno Wessely , Nakul Samala , Lars Hillemann , Daniel Göhler , Jan Müller , Claudia Jahn-Wolf , Andreas Rudolph , Jens Lienig","doi":"10.1016/j.jaerosci.2025.106611","DOIUrl":"10.1016/j.jaerosci.2025.106611","url":null,"abstract":"<div><div>Light scattering aerosol spectrometers (also known as optical particle counters, OPCs) are widely used for aerosol quantification. The single particle counting method, which is based on light scattering, can measure the size distribution and the number concentration of the sampled aerosol. However, this method is limited to low concentrations due to coincidence error. At higher concentrations, the particle pulses overlap and cannot be counted individually. It was recently shown that the detector signal of an optical aerosol spectrometer can also be evaluated by fluctuation analysis if the concentration is significantly higher than the coincidence limit of the device. This new mode of operation cannot yet provide a detailed size distribution but itis feasible to measure the median particle size and number concentration independently. The measurement information required for fluctuation analysis is drawn from the intensity distribution of the detector signal instead of individual pulses. Therefore, fluctuation analysis requires a certain average number of particles inside the measuring volume so that the detector output continuously leaves the baseline. Theminimum number concentration of the fluctuation analysis is around a factor of20 higher than the coincidence limit for single particle counting. Consequently, there is a concentration range where neither single particle counting, nor fluctuation analysis can be used.</div><div>This work introduces a new statistical signal analysis to bridge this gap. The new measurement method was experimentally verified using a monodisperse di-ethyl-hexyl-sebacat aerosol with a particle size range of 0.3<!--> <!-->µm to 2.2<!--> <!-->µm and a number concentration range of 1 <span><math><mo>×</mo></math></span> 10<sup>4</sup> <!-->cm<sup>−3</sup> to 2 <span><math><mo>×</mo></math></span> 10<sup>5</sup> <!-->cm<sup>−3</sup>. An accuracy of 2<!--> <!-->% with respect to median particle size and 5<!--> <!-->% with respect to number concentration was achieved. The new method finally closes the gap between single particle counting and fluctuation analysis, enabling light scattering aerosol spectrometers to quantify aerosols at any given concentration.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"188 ","pages":"Article 106611"},"PeriodicalIF":3.9,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144168577","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 : 2025-05-26DOI: 10.1016/j.jaerosci.2025.106619
Anna Tuhkuri Matvejeff , Ville Silvonen , Paavo Heikkilä , Enni Sanmark , Jani Hakala , Niina Kuittinen , Ahmed Geneid , Anne-Maria Laukkanen , Paavo Alku , Lotta-Maria Oksanen , Topi Rönkkö , Aimo Taipale , Sampo Saari
Spurred by the SARS-CoV-2 pandemic, there has been a considerable increase in research on human respiratory particle characterization using diverse methodologies. Our objective was to review previous methods used and to develop a highly controlled method for measuring human respiratory particle emissions during breathing, coughing, and voice production. A systematic search from three databases (Ovid Medline, Web of Science, and Scopus) was carried out in January 2024 according to the PRISMA 2020 principles. 77 original studies were included in the qualitative analysis. Considerable variation was noted in the methodology of previous particle measurement studies regarding setups, instrumentation, protocols, and reporting. We identified six key setups and discuss factors such as relative humidity, particle losses, and dilution for each.
We also present our novel setup, comprising a measurement chamber with particle-free air supply, funnel-type sample inlet, and real-time particle measurement instruments to investigate the absolute and time-resolved exhaled aerosol emission rates. The drying and dilution processes of particles, as well as particle losses, are well controlled. CO2 measurements are utilized for sample dilution and exhaled flow estimation. Optional sound pressure measurement provides calibrated absolute values. Fundamental frequency and electroglottography registration are also included as optional tools for studying voice production. Our setup reports accurate data on particle number concentration, mass concentration, particle number emission, and mass emission rates during breathing, coughing, speaking, and singing in the size range 0.004–10 μm, therefore succeeding in measuring ultrafine particles. We also report a positive effect of sound pressure and CO2 on particle emissions.
Enhanced methods for particle emission measurements improve our understanding of airborne transmission and human physiology, providing tools to minimize the risk of airborne transmission. We propose a set of key methodological parameters for improved reporting, including the documentation of dilution, particle drying, sampling losses and sound pressure.
在SARS-CoV-2大流行的推动下，使用各种方法对人类呼吸道颗粒特征的研究大大增加。我们的目标是回顾以前使用的方法，并开发一种高度控制的方法来测量人类呼吸，咳嗽和声音产生过程中的呼吸道颗粒排放。根据PRISMA 2020原则，于2024年1月对三个数据库（Ovid Medline、Web of Science和Scopus）进行了系统检索。定性分析纳入了77项原始研究。在以前的颗粒测量研究中，关于设置、仪器、协议和报告的方法存在相当大的差异。我们确定了六个关键设置，并讨论了诸如相对湿度、颗粒损失和稀释等因素。我们还介绍了我们的新装置，包括一个无颗粒空气供应的测量室，漏斗型样品入口和实时颗粒测量仪器，以研究绝对和时间分辨的呼出气溶胶排放率。颗粒的干燥和稀释过程以及颗粒损失都得到了很好的控制。二氧化碳测量用于样品稀释和呼出流量估计。可选的声压测量提供校准的绝对值。基本频率和声门电图登记也包括作为可选的工具来研究声音的产生。我们的装置报告了0.004-10 μm范围内呼吸、咳嗽、说话和唱歌过程中粒子数浓度、质量浓度、粒子数发射和质量发射率的准确数据，因此成功测量了超细颗粒。我们还报告了声压和二氧化碳对颗粒排放的积极影响。增强的颗粒排放测量方法提高了我们对空气传播和人体生理学的理解，为减少空气传播的风险提供了工具。我们提出了一套改进报告的关键方法参数，包括稀释、颗粒干燥、采样损失和声压的记录。
{"title":"Systematic review of respiratory particle measurement studies and a new method for human particle emission measurement during breathing, coughing, and voice production","authors":"Anna Tuhkuri Matvejeff , Ville Silvonen , Paavo Heikkilä , Enni Sanmark , Jani Hakala , Niina Kuittinen , Ahmed Geneid , Anne-Maria Laukkanen , Paavo Alku , Lotta-Maria Oksanen , Topi Rönkkö , Aimo Taipale , Sampo Saari","doi":"10.1016/j.jaerosci.2025.106619","DOIUrl":"10.1016/j.jaerosci.2025.106619","url":null,"abstract":"<div><div>Spurred by the SARS-CoV-2 pandemic, there has been a considerable increase in research on human respiratory particle characterization using diverse methodologies. Our objective was to review previous methods used and to develop a highly controlled method for measuring human respiratory particle emissions during breathing, coughing, and voice production. A systematic search from three databases (Ovid Medline, Web of Science, and Scopus) was carried out in January 2024 according to the PRISMA 2020 principles. 77 original studies were included in the qualitative analysis. Considerable variation was noted in the methodology of previous particle measurement studies regarding setups, instrumentation, protocols, and reporting. We identified six key setups and discuss factors such as relative humidity, particle losses, and dilution for each.</div><div>We also present our novel setup, comprising a measurement chamber with particle-free air supply, funnel-type sample inlet, and real-time particle measurement instruments to investigate the absolute and time-resolved exhaled aerosol emission rates. The drying and dilution processes of particles, as well as particle losses, are well controlled. CO<sub>2</sub> measurements are utilized for sample dilution and exhaled flow estimation. Optional sound pressure measurement provides calibrated absolute values. Fundamental frequency and electroglottography registration are also included as optional tools for studying voice production. Our setup reports accurate data on particle number concentration, mass concentration, particle number emission, and mass emission rates during breathing, coughing, speaking, and singing in the size range 0.004–10 μm, therefore succeeding in measuring ultrafine particles. We also report a positive effect of sound pressure and CO<sub>2</sub> on particle emissions.</div><div>Enhanced methods for particle emission measurements improve our understanding of airborne transmission and human physiology, providing tools to minimize the risk of airborne transmission. We propose a set of key methodological parameters for improved reporting, including the documentation of dilution, particle drying, sampling losses and sound pressure.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"189 ","pages":"Article 106619"},"PeriodicalIF":3.9,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364564","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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