Pub Date : 2026-01-01Epub Date: 2025-11-01DOI: 10.1016/j.jaerosci.2025.106708
Kennet Braasch, Alexander Teplyuk, Michael Höft
In this work, a Doppler Radar sensor with a transmitting frequency of GHz is presented for the continuous real-time monitoring of particles. This measurement approach has advantages over more common methods. Especially, the huge measurement volume sets this method apart and makes it ideal for industrial combustion processes. The theoretical background for the approach is presented and discussed. A setup is constructed and measurements are conducted which serve as proof-of-concept for the monitoring of particle concentration. Two different particle sizes of m and m are used for these measurements, which are within the typical regime for the application.
{"title":"Real-time monitoring of particle concentrations within an air stream using a high-frequency Doppler Radar Sensor","authors":"Kennet Braasch, Alexander Teplyuk, Michael Höft","doi":"10.1016/j.jaerosci.2025.106708","DOIUrl":"10.1016/j.jaerosci.2025.106708","url":null,"abstract":"<div><div>In this work, a Doppler Radar sensor with a transmitting frequency of <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>T</mi></mrow></msub><mo>=</mo><mn>140</mn></mrow></math></span> <!--> <!-->GHz is presented for the continuous real-time monitoring of particles. This measurement approach has advantages over more common methods. Especially, the huge measurement volume sets this method apart and makes it ideal for industrial combustion processes. The theoretical background for the approach is presented and discussed. A setup is constructed and measurements are conducted which serve as proof-of-concept for the monitoring of particle concentration. Two different particle sizes of <span><math><mrow><mn>17</mn><mo>.</mo><mn>3</mn><mspace></mspace><mi>μ</mi></mrow></math></span>m and <span><math><mrow><mn>12</mn><mo>.</mo><mn>8</mn><mspace></mspace><mi>μ</mi></mrow></math></span>m are used for these measurements, which are within the typical regime for the application.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106708"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462743","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}
Quasi-ultrafine particles (q-UFPs; 30 nm < dp < 170 nm) are increasingly recognized as potent contributors to air pollution-related health effects due to their physicochemical characteristics and deep lung penetration. This study investigated the size-segregated chemical composition and oxidative potential of ambient particles in the q-UFPs and accumulation mode ranges (30 nm - 2.5 μm) in central Los Angeles. A Low-Pressure Impactor (LPI), coupled with a Versatile Aerosol Concentration Enrichment System (VACES), was employed alongside a Sioutas Personal Cascade Impactor (PCIS) to collect size-fractionated PM for mass, elemental, ionic, carbonaceous, and toxicological analysis. Mass concentrations in q-UFPs (30–170 nm) were significantly lower than those in the accumulation mode (250–2500 nm), with the latter mode contributing >83 % of total PM mass. Dithiothreitol (DTT) activity was observed to increase across q-UFP size bins, peaking in the 108–170 nm range at 25.98 pmol/min/m3 in winter and 44.31 pmol/min/m3 in summer/fall. In the accumulation mode, slightly lower DTT activity levels were measured (23.95 and 39.98 pmol/min/m3, respectively). Strong positive correlations were identified between DTT activity and elemental carbon (r = 0.95), organic carbon (r = 0.94), ammonium (r = 0.93), and sulfate (r = 0.91), suggesting contributions from both primary emissions and secondary atmospheric processes. Respiratory deposition modeling using the International Commission on Radiological Protection (ICRP) method showed that although q-UFPs comprised a smaller fraction of the total mass, they were found to contribute 29 % of the cumulative alveolar-region dose, with the 108–170 nm fraction alone delivering 31.5 pmol/min. These results highlight the toxicological importance of UFPs and support the need for continued monitoring and research, consistent with the World Health Organization's good practice statements, which recommend the integration of UFP metrics into air quality monitoring frameworks in the absence of formal guideline values.
{"title":"Size-segregated chemical composition and oxidative potential of ambient quasi-ultrafine and accumulation mode particles in Los Angeles","authors":"Yashar Aghaei , Mohammad Mahdi Badami , Mohammad Aldekheel , Ramin Tohidi , Yousef Alramzi , P.S. Ganesh Subramanian , Vishal Verma , Leonidas Ntziachristos , Constantinos Sioutas","doi":"10.1016/j.jaerosci.2025.106696","DOIUrl":"10.1016/j.jaerosci.2025.106696","url":null,"abstract":"<div><div>Quasi-ultrafine particles (q-UFPs; 30 nm < d<sub>p</sub> < 170 nm) are increasingly recognized as potent contributors to air pollution-related health effects due to their physicochemical characteristics and deep lung penetration. This study investigated the size-segregated chemical composition and oxidative potential of ambient particles in the q-UFPs and accumulation mode ranges (30 nm - 2.5 μm) in central Los Angeles. A Low-Pressure Impactor (LPI), coupled with a Versatile Aerosol Concentration Enrichment System (VACES), was employed alongside a Sioutas Personal Cascade Impactor (PCIS) to collect size-fractionated PM for mass, elemental, ionic, carbonaceous, and toxicological analysis. Mass concentrations in q-UFPs (30–170 nm) were significantly lower than those in the accumulation mode (250–2500 nm), with the latter mode contributing >83 % of total PM mass. Dithiothreitol (DTT) activity was observed to increase across q-UFP size bins, peaking in the 108–170 nm range at 25.98 pmol/min/m<sup>3</sup> in winter and 44.31 pmol/min/m<sup>3</sup> in summer/fall. In the accumulation mode, slightly lower DTT activity levels were measured (23.95 and 39.98 pmol/min/m<sup>3</sup>, respectively). Strong positive correlations were identified between DTT activity and elemental carbon (r = 0.95), organic carbon (r = 0.94), ammonium (r = 0.93), and sulfate (r = 0.91), suggesting contributions from both primary emissions and secondary atmospheric processes. Respiratory deposition modeling using the International Commission on Radiological Protection (ICRP) method showed that although q-UFPs comprised a smaller fraction of the total mass, they were found to contribute 29 % of the cumulative alveolar-region dose, with the 108–170 nm fraction alone delivering 31.5 pmol/min. These results highlight the toxicological importance of UFPs and support the need for continued monitoring and research, consistent with the World Health Organization's good practice statements, which recommend the integration of UFP metrics into air quality monitoring frameworks in the absence of formal guideline values.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106696"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097212","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 : 2026-01-01Epub Date: 2025-09-15DOI: 10.1016/j.jaerosci.2025.106698
Marie Bermeo , Markus Snellman , Linnéa Jönsson , Thomas Krinke , Zhongshan Li , Knut Deppert , Maria E. Messing
Pd-Ga alloy nanoparticles with tunable compositions were produced by combining spark ablation with a downstream injection of a metal-organic precursor. This dual-process approach enables control over nanoparticle composition and morphology by adjusting precursor flow rate and sintering temperature. At lower precursor flows, uniform Pd-Ga nanoparticles form, exhibiting stable Pd5Ga2 and Pd2Ga phases. HRTEM and STEM-EDX analyses reveal that as precursor supply increases, Ga incorporation intensifies, leading to structural transitions, phase segregation, and the formation of PdGa dominated phases with amorphous Ga-rich domains, influencing nanoparticle shape and crystallinity. This process unlocks pathways for tailoring alloy compositions in-flight with low-melting point materials.
{"title":"Engineered Pd-Ga alloy nanoparticles through spark ablation and in-flight metal-organic precursor decomposition","authors":"Marie Bermeo , Markus Snellman , Linnéa Jönsson , Thomas Krinke , Zhongshan Li , Knut Deppert , Maria E. Messing","doi":"10.1016/j.jaerosci.2025.106698","DOIUrl":"10.1016/j.jaerosci.2025.106698","url":null,"abstract":"<div><div>Pd-Ga alloy nanoparticles with tunable compositions were produced by combining spark ablation with a downstream injection of a metal-organic precursor. This dual-process approach enables control over nanoparticle composition and morphology by adjusting precursor flow rate and sintering temperature. At lower precursor flows, uniform Pd-Ga nanoparticles form, exhibiting stable Pd<sub>5</sub>Ga<sub>2</sub> and Pd<sub>2</sub>Ga phases. HRTEM and STEM-EDX analyses reveal that as precursor supply increases, Ga incorporation intensifies, leading to structural transitions, phase segregation, and the formation of PdGa dominated phases with amorphous Ga-rich domains, influencing nanoparticle shape and crystallinity. This process unlocks pathways for tailoring alloy compositions in-flight with low-melting point materials.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106698"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109743","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 : 2026-01-01Epub Date: 2025-09-20DOI: 10.1016/j.jaerosci.2025.106699
Taewon T. Han , Atila Lima , Dong Ming He , Gary Brewer , Gediminas Mainelis
This research aimed to advance the development of a novel personal nasal sampler (PNS). PNS attaches to a user's nostrils and utilizes the user's breathing to capture airborne infectious agents on an advanced filter inside the PNS, thereby directly measuring actual personal exposure to those agents. Here, we designed, developed, and tested a hybrid filter (HF) to be used in PNS. The HF was designed by overlaying electrospun polyvinylidene fluoride (PVDF) nanofibers on a selected substrate for different durations. A suitable substrate was selected from meltblown and spunbond fabric filters of different densities, a MERV-5 carbon filter, and a pulmonary function test filter (PTF) based on their collection efficiencies and pressure drop. The candidate hybrid filters (HF) were then challenged with Arizona Road Dust particles aerosolized from a 2 % w/w slurry. The HF was 12.5 mm in diameter, corresponding to an average nostril diameter, and was operated at 5 and 10 L/min flow rates to simulate sedentary conditions and moderate exertion, respectively. The final HF showed collection efficiency of 60–70 % at 0.2–0.3 μm (most penetrating particle size) and >90 % for particles <0.05 μm and >0.7 μm. Its pressure drop was about 200 Pa. When challenged with enveloped bacteriophage Phi6, this HF showed recovery efficiencies of 99 % and 80 % at 5 and 10 L/min flow rates, respectively. In the next steps, the HF will be incorporated into a biocompatible holder and extensively tested in laboratory and field conditions for its ability to measure exposure to bioaerosols.
{"title":"Development of an advanced personal nasal sampler (PNS) to access exposure to bioaerosols","authors":"Taewon T. Han , Atila Lima , Dong Ming He , Gary Brewer , Gediminas Mainelis","doi":"10.1016/j.jaerosci.2025.106699","DOIUrl":"10.1016/j.jaerosci.2025.106699","url":null,"abstract":"<div><div>This research aimed to advance the development of a novel personal nasal sampler (PNS). PNS attaches to a user's nostrils and utilizes the user's breathing to capture airborne infectious agents on an advanced filter inside the PNS, thereby directly measuring actual personal exposure to those agents. Here, we designed, developed, and tested a hybrid filter (HF) to be used in PNS. The HF was designed by overlaying electrospun polyvinylidene fluoride (PVDF) nanofibers on a selected substrate for different durations. A suitable substrate was selected from meltblown and spunbond fabric filters of different densities, a MERV-5 carbon filter, and a pulmonary function test filter (PTF) based on their collection efficiencies and pressure drop. The candidate hybrid filters (HF) were then challenged with Arizona Road Dust particles aerosolized from a 2 % w/w slurry. The HF was 12.5 mm in diameter, corresponding to an average nostril diameter, and was operated at 5 and 10 L/min flow rates to simulate sedentary conditions and moderate exertion, respectively. The final HF showed collection efficiency of 60–70 % at 0.2–0.3 μm (most penetrating particle size) and >90 % for particles <0.05 μm and >0.7 μm. Its pressure drop was about 200 Pa. When challenged with enveloped bacteriophage Phi6, this HF showed recovery efficiencies of 99 % and 80 % at 5 and 10 L/min flow rates, respectively. In the next steps, the HF will be incorporated into a biocompatible holder and extensively tested in laboratory and field conditions for its ability to measure exposure to bioaerosols.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106699"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119716","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 : 2026-01-01Epub Date: 2025-09-26DOI: 10.1016/j.jaerosci.2025.106682
Brenda Vara Almirall , Narinder Singh , Hua Qian Ang , Kiao Inthavong
Accurate representation of oral airway geometry during inhalation is critical for optimizing drug delivery, yet the shape of the oral cavity and oropharynx varies significantly with breathing posture. This pilot study compares airflow dynamics and particle deposition between two CT-derived airway models from a single healthy subject: one with an artificially opened mouth during nasal breathing, and another with a real oral inhalation during active oral inhalation using a 2 cm mouthpiece. Computational fluid dynamics simulations were conducted at inhalation rates of 15, 30, and 60 L/min using spherical particles. The real-oral-inhalation model showed an enlarged oral cavity, smoother and more uniform airflow, peak pharyngeal velocities of 5–6 m/s, and an anteriorly directed laryngeal jet. This airway geometry eliminated oral cavity deposition and consistently shifted particle deposition deeper into the airway, resulting in 17–19.6% deposition in the larynx across all flow rates. In contrast, the artificially opened model produced higher peak velocities ( 7.5 m/s), jet-like flow impinging on the posterior pharyngeal wall, and persistent oral cavity deposition that increased with flow rate. Tracheal deposition remained minimal in both models. Differences in tongue and soft palate positioning, likely contributed to the observed aerodynamic and deposition patterns. These results highlight the role of imaging protocols that capture true inhalation posture and soft tissue configuration. Future studies that incorporate the realistic airway geometry during physiologically realistic breathing conditions may provide new inhalation drug delivery strategies and improve clinical relevance of CFD-based inhalation models.
{"title":"Impact of oral cavity geometry on micro-sized aerosol deposition in the upper airway during oral inhalation","authors":"Brenda Vara Almirall , Narinder Singh , Hua Qian Ang , Kiao Inthavong","doi":"10.1016/j.jaerosci.2025.106682","DOIUrl":"10.1016/j.jaerosci.2025.106682","url":null,"abstract":"<div><div>Accurate representation of oral airway geometry during inhalation is critical for optimizing drug delivery, yet the shape of the oral cavity and oropharynx varies significantly with breathing posture. This pilot study compares airflow dynamics and particle deposition between two CT-derived airway models from a single healthy subject: one with an artificially opened mouth during nasal breathing, and another with a real oral inhalation during active oral inhalation using a 2 cm mouthpiece. Computational fluid dynamics simulations were conducted at inhalation rates of 15, 30, and 60 L/min using spherical particles. The real-oral-inhalation model showed an enlarged oral cavity, smoother and more uniform airflow, peak pharyngeal velocities of 5–6 m/s, and an anteriorly directed laryngeal jet. This airway geometry eliminated oral cavity deposition and consistently shifted particle deposition deeper into the airway, resulting in 17–19.6% deposition in the larynx across all flow rates. In contrast, the artificially opened model produced higher peak velocities (<span><math><mo>≈</mo></math></span> 7.5 m/s), jet-like flow impinging on the posterior pharyngeal wall, and persistent oral cavity deposition that increased with flow rate. Tracheal deposition remained minimal in both models. Differences in tongue and soft palate positioning, likely contributed to the observed aerodynamic and deposition patterns. These results highlight the role of imaging protocols that capture true inhalation posture and soft tissue configuration. Future studies that incorporate the realistic airway geometry during physiologically realistic breathing conditions may provide new inhalation drug delivery strategies and improve clinical relevance of CFD-based inhalation models.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106682"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221942","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 : 2026-01-01Epub Date: 2025-09-26DOI: 10.1016/j.jaerosci.2025.106702
Mohamed Talaat , Xiuhua April Si , Jinxiang Xi
The effectiveness of metered-dose inhalers (MDIs) in drug delivery is significantly influenced by aerosol dynamics, particularly evaporation and release timing. This study examined the dynamic interactions between these two factors and their impact on deposition patterns in an anatomically realistic airway model. The airflow and thermo-humidity conditions were simulated under spray actuation conditions (i.e., 0.0, 0.7, 1.5, and 2.5 s after inhalation onset). A Lagrangian-based multiphase model, enhanced with adaptive droplet time steps, was used to track droplet evaporation, trajectory, and deposition. Experimentally measured MDI spray properties, including solution composition, polydisperse size distribution, plume angle, and release velocity, were implemented as initial/boundary conditions. Dosimetry was quantified based on both the count and mass of deposited droplets. Results revealed large differences in droplet evaporation between Case 0.0 s and the other three cases. For all release times, evaporation decreased droplet deposition in the mouth and increased deposition in the lower lung, particularly in the two upper lobes. Droplets starting at 5 μm in diameter reduced to 0.93–2.8 μm within 50–200 ms in the respiratory tract, whereas 10 μm droplets shrunk only to 7.5 μm. The spray deposition pattern varies notably depending on whether actuation occurs at the start of inhalation or is delayed by 0.7–2.5 s. This variation stems from slower airflow and extended evaporation time at the beginning of inhalation vs. relatively consistent and quicker evaporation rates in delayed actuation. Correction factors were introduced for delayed actuation cases to align deposition data obtained with and without accounting for droplet evaporation. Because of the initial polydisperse size distribution and subsequent evaporation of spray droplets, mass-based and count-based deposition fraction values in the lower lung differed by one order of magnitude. Further experimental studies are needed to validate predictions regarding droplet behavior and fate in the respiratory tract.
{"title":"Computational insights into dynamic impacts of droplet evaporation and spray release timing on MDI dosimetry in the respiratory tract","authors":"Mohamed Talaat , Xiuhua April Si , Jinxiang Xi","doi":"10.1016/j.jaerosci.2025.106702","DOIUrl":"10.1016/j.jaerosci.2025.106702","url":null,"abstract":"<div><div>The effectiveness of metered-dose inhalers (MDIs) in drug delivery is significantly influenced by aerosol dynamics, particularly evaporation and release timing. This study examined the dynamic interactions between these two factors and their impact on deposition patterns in an anatomically realistic airway model. The airflow and thermo-humidity conditions were simulated under spray actuation conditions (i.e., 0.0, 0.7, 1.5, and 2.5 s after inhalation onset). A Lagrangian-based multiphase model, enhanced with adaptive droplet time steps, was used to track droplet evaporation, trajectory, and deposition. Experimentally measured MDI spray properties, including solution composition, polydisperse size distribution, plume angle, and release velocity, were implemented as initial/boundary conditions. Dosimetry was quantified based on both the count and mass of deposited droplets. Results revealed large differences in droplet evaporation between Case 0.0 s and the other three cases. For all release times, evaporation decreased droplet deposition in the mouth and increased deposition in the lower lung, particularly in the two upper lobes. Droplets starting at 5 μm in diameter reduced to 0.93–2.8 μm within 50–200 ms in the respiratory tract, whereas 10 μm droplets shrunk only to 7.5 μm. The spray deposition pattern varies notably depending on whether actuation occurs at the start of inhalation or is delayed by 0.7–2.5 s. This variation stems from slower airflow and extended evaporation time at the beginning of inhalation vs. relatively consistent and quicker evaporation rates in delayed actuation. Correction factors were introduced for delayed actuation cases to align deposition data obtained with and without accounting for droplet evaporation. Because of the initial polydisperse size distribution and subsequent evaporation of spray droplets, mass-based and count-based deposition fraction values in the lower lung differed by one order of magnitude. Further experimental studies are needed to validate predictions regarding droplet behavior and fate in the respiratory tract.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106702"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221943","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 : 2026-01-01Epub Date: 2025-09-04DOI: 10.1016/j.jaerosci.2025.106676
Schuyler P. Lockwood, Zezhen Cheng, Valentina Sola, Nurun Nahar Lata, Tanya L. Myers, Timothy J. Johnson, Mark E. Bowden, Alla Zelenyuk
Titanium dioxide (TiO2) particulates are known to exhibit different visible and infrared optical properties compared to the bulk material, showing strong dependence on particle size, crystal structure, and morphology. In this study, the optical properties, sizes, and morphologies of TiO2 particles from two different sources (nano and fine powders) having a) nominally different particle sizes and b) various crystal polymorph mixture fractions are compared using a combination of single particle mass spectrometry, optical spectroscopies, and aerosol characterization methods. The nano sample was found to be largely particles of the anatase polymorph (88% by mass), while the fine sample was found to consist largely of rutile particles (95% by mass). Two distinct particle morphologies (fractal and compact) were found in each powder sample and could be identified and separated in-situ based on particle aerodynamic properties. The attenuation of near-infrared, visible and ultraviolet light by TiO2 particles shows strong dependence on particle morphology. While the fine particles were found to have larger near-infrared (675–800 nm) extinction coefficients by mass than the nanoparticles, the reverse was true in the ultraviolet and visible regions (370–675 nm). However, for polydisperse particles with different sizes and shapes, the optical behaviors are not straightforward to directly correlate to a combination of physical parameters.
{"title":"Correlation of optical properties with particle size, morphology, and polymorph of fine- and nano-particle formulations of titanium dioxide powders","authors":"Schuyler P. Lockwood, Zezhen Cheng, Valentina Sola, Nurun Nahar Lata, Tanya L. Myers, Timothy J. Johnson, Mark E. Bowden, Alla Zelenyuk","doi":"10.1016/j.jaerosci.2025.106676","DOIUrl":"10.1016/j.jaerosci.2025.106676","url":null,"abstract":"<div><div>Titanium dioxide (TiO<sub>2</sub>) particulates are known to exhibit different visible and infrared optical properties compared to the bulk material, showing strong dependence on particle size, crystal structure, and morphology. In this study, the optical properties, sizes, and morphologies of TiO<sub>2</sub> particles from two different sources (nano and fine powders) having a) nominally different particle sizes and b) various crystal polymorph mixture fractions are compared using a combination of single particle mass spectrometry, optical spectroscopies, and aerosol characterization methods. The nano sample was found to be largely particles of the anatase polymorph (88% by mass), while the fine sample was found to consist largely of rutile particles (95% by mass). Two distinct particle morphologies (fractal and compact) were found in each powder sample and could be identified and separated <em>in-situ</em> based on particle aerodynamic properties. The attenuation of near-infrared, visible and ultraviolet light by TiO<sub>2</sub> particles shows strong dependence on particle morphology. While the fine particles were found to have larger near-infrared (675–800 nm) extinction coefficients by mass than the nanoparticles, the reverse was true in the ultraviolet and visible regions (370–675 nm). However, for polydisperse particles with different sizes and shapes, the optical behaviors are not straightforward to directly correlate to a combination of physical parameters.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106676"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097210","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 : 2026-01-01Epub Date: 2025-09-19DOI: 10.1016/j.jaerosci.2025.106700
Anton Patarashvili, Alexey Efimov, Dmitry Maslennikov, Matthew Ivanov, Dmitry Labutov, Ekaterina Kameneva, Olesya Vershinina, Victor Ivanov
This study presents an optimized spark-discharge generator circuit that enhances unipolar ion production (up to 109 ions/cm3) without any ionizers, enabling efficient generation of charged ultrafine nanoparticles (<5 nm). By sustaining high voltage on both electrodes during discharge, the system achieves stable and controllable unipolar ionization. Systematic evaluation of key parameters (interelectrode gap, electrode material, discharge frequency, capacitance, gas flow/type, and voltage polarity) reveals optimal conditions for ion generation. Deposition experiments on silicon substrates and TEM grids confirm a 4-fold increase in sub-5 nm charged nanoparticle production compared to conventional designs, as validated by TEM, SEM and optical profilometry.
{"title":"Charged ultrafine nanoparticle synthesis by spark-discharge","authors":"Anton Patarashvili, Alexey Efimov, Dmitry Maslennikov, Matthew Ivanov, Dmitry Labutov, Ekaterina Kameneva, Olesya Vershinina, Victor Ivanov","doi":"10.1016/j.jaerosci.2025.106700","DOIUrl":"10.1016/j.jaerosci.2025.106700","url":null,"abstract":"<div><div>This study presents an optimized spark-discharge generator circuit that enhances unipolar ion production (up to 10<sup>9</sup> ions/cm<sup>3</sup>) without any ionizers, enabling efficient generation of charged ultrafine nanoparticles (<5 nm). By sustaining high voltage on both electrodes during discharge, the system achieves stable and controllable unipolar ionization. Systematic evaluation of key parameters (interelectrode gap, electrode material, discharge frequency, capacitance, gas flow/type, and voltage polarity) reveals optimal conditions for ion generation. Deposition experiments on silicon substrates and TEM grids confirm a 4-fold increase in sub-5 nm charged nanoparticle production compared to conventional designs, as validated by TEM, SEM and optical profilometry.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106700"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156568","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 : 2026-01-01Epub Date: 2025-09-04DOI: 10.1016/j.jaerosci.2025.106679
Jingjing Xia , Chaohao Yang , Jin Zeng
In situ and on-line measurement of soot's particle size distribution (PSD) is crucial for comprehending its physical and chemical properties. The non-contact nature and high sensitivity of optical techniques have led to their widespread adoption in soot characterization. To overcome the computational burden associated with modeling fractal structures, this study utilizes the discrete dipole approximation (DDA) to represent soot as ellipsoids. Meanwhile, a miniaturized prototype sensor was utilized to collect the light scattering phase function (LSPF), providing sufficient optical information to retrieve soot's PSD. Experiments with Di-Ethyl-Hexyl-Sebacate (DEHS) demonstrated that the prototype sensor can accurately collect the LSPF, with a maximum relative error (RE) below 15 %. The Kullback-Leibler divergence (DKL) of the PSD retrieved by the hybrid iterative inversion algorithm that was proposed in this study is no larger than 0.05. Further testing with open-flame combustion confirmed that the method proposed in this study can accurately sense soot's PSD and decouple its ovality parameter (OP). The method proposed in this study exhibits significant potential for in situ and on-line measurement of soot's PSD and provides a reliable framework for characterizing irregular particles.
{"title":"In situ and on-line measurement of soot size using the light-based method","authors":"Jingjing Xia , Chaohao Yang , Jin Zeng","doi":"10.1016/j.jaerosci.2025.106679","DOIUrl":"10.1016/j.jaerosci.2025.106679","url":null,"abstract":"<div><div>In situ and on-line measurement of soot's particle size distribution (PSD) is crucial for comprehending its physical and chemical properties. The non-contact nature and high sensitivity of optical techniques have led to their widespread adoption in soot characterization. To overcome the computational burden associated with modeling fractal structures, this study utilizes the discrete dipole approximation (DDA) to represent soot as ellipsoids. Meanwhile, a miniaturized prototype sensor was utilized to collect the light scattering phase function (LSPF), providing sufficient optical information to retrieve soot's PSD. Experiments with Di-Ethyl-Hexyl-Sebacate (DEHS) demonstrated that the prototype sensor can accurately collect the LSPF, with a maximum relative error (RE) below 15 %. The Kullback-Leibler divergence (<em>D</em><sub><em>KL</em></sub>) of the PSD retrieved by the hybrid iterative inversion algorithm that was proposed in this study is no larger than 0.05. Further testing with open-flame combustion confirmed that the method proposed in this study can accurately sense soot's PSD and decouple its ovality parameter (OP). The method proposed in this study exhibits significant potential for in situ and on-line measurement of soot's PSD and provides a reliable framework for characterizing irregular particles.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106679"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145048090","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 : 2026-01-01Epub Date: 2025-09-18DOI: 10.1016/j.jaerosci.2025.106697
Kawkab Ahasan, Md Sadiqul Islam, Pranav Shrotriya, Todd A. Kingston
Growing concerns about public health and national security necessitate the development of compact, integrated systems capable of continuous, real-time collection and detection of biothreats (e.g., viruses and bacteria). In this work, we report an inertial microfluidic-based aerosol capture device for the real-time collection and analysis of airborne particles (e.g., biothreats), motivated by the need for rapid detection capabilities. A two-stage spiral microchannel is designed, fabricated, and evaluated for capturing aerosolized particles with diameters ranging from 0.20 to 1.60 μm, and its performance is compared to a traditional U-shaped microchannel. The spiral microchannel design is developed with the aid of multiphase computational fluid dynamics (CFD) simulations and tested experimentally to investigate the flow dynamics and particle capture efficiencies. Overall, the experimentally measured particle capture efficiencies agreed well with the simulation results and the two-stage spiral microchannel resulted in significant improvement over the traditional U-shaped microchannel. Both the simulations and experiments on the spiral microchannel design demonstrated approximately a two-fold increase in diversion efficiency and a five-fold increase in entrapment efficiency, on average, while having less than a two-fold increase in pressure drop. The performance improvement in the two-stage spiral microchannel design suggests a promising avenue for the development of next-generation devices capable of providing real-time collection and enrichment of aerosolized biothreats.
{"title":"Stratified two-phase microfluidic device for continuous sampling of sub-micron aerosolized particles","authors":"Kawkab Ahasan, Md Sadiqul Islam, Pranav Shrotriya, Todd A. Kingston","doi":"10.1016/j.jaerosci.2025.106697","DOIUrl":"10.1016/j.jaerosci.2025.106697","url":null,"abstract":"<div><div>Growing concerns about public health and national security necessitate the development of compact, integrated systems capable of continuous, real-time collection and detection of biothreats (e.g., viruses and bacteria). In this work, we report an inertial microfluidic-based aerosol capture device for the real-time collection and analysis of airborne particles (e.g., biothreats), motivated by the need for rapid detection capabilities. A two-stage spiral microchannel is designed, fabricated, and evaluated for capturing aerosolized particles with diameters ranging from 0.20 to 1.60 μm, and its performance is compared to a traditional U-shaped microchannel. The spiral microchannel design is developed with the aid of multiphase computational fluid dynamics (CFD) simulations and tested experimentally to investigate the flow dynamics and particle capture efficiencies. Overall, the experimentally measured particle capture efficiencies agreed well with the simulation results and the two-stage spiral microchannel resulted in significant improvement over the traditional U-shaped microchannel. Both the simulations and experiments on the spiral microchannel design demonstrated approximately a two-fold increase in diversion efficiency and a five-fold increase in entrapment efficiency, on average, while having less than a two-fold increase in pressure drop. The performance improvement in the two-stage spiral microchannel design suggests a promising avenue for the development of next-generation devices capable of providing real-time collection and enrichment of aerosolized biothreats.</div></div>","PeriodicalId":14880,"journal":{"name":"Journal of Aerosol Science","volume":"191 ","pages":"Article 106697"},"PeriodicalIF":2.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221940","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号