Pub Date : 2023-10-18DOI: 10.1080/02786826.2023.2261715
Mahender Singh Rawat, Mehtap Agirsoy, Dinushani Senarathna, Byron D. Erath, Tanvir Ahmed, Sumona Mondal, Andrea R. Ferro
AbstractRespiratory aerosols arise due to bronchial fluid film bursting within the pulmonary tract, the vibration of the vocal folds during phonation, and articulation of the tongue/lips/teeth. We expect respiratory aerosol emission rates to be lower in children than adults due to the smaller size of their laryngeal structure, reduced sub-glottal pressure created during speech, and reduced number of alveoli. However, few studies have evaluated respiratory aerosols for children. We recruited 50 participants from three age categories: children aged 6−11 years, children aged 12−18 years, and adults ( >18 years). We investigated particle emissions for three different 5 s sustained vocalizations of /a/ or /pa/ at 262 Hz, as well as for running speech and breathing. The particle generation rate ranged from 0 to 488 particles/s. Children aged 6−11 years produced fewer particles (mean 12 ± SD 9 particles/s) than children aged 12−18 years (23 ± 19 particles/s) and adults (70 ± 73 particles/s). Taking a deep breath before vocalizing /a/ resulted in higher aerosol emission rates than the baseline case. The particle number size distributions for all vocalizations and age groups consistently showed two modes at ≈0.6 μm and ≈2 μm. Children had a slightly smaller primary mode location and larger secondary mode location than adults. Superemitters (statistical outliers) were found in all groups. Experiments repeated over time revealed large intrapersonal variability indicating additional variables (e.g., environmental, physiological, behavioral) may significantly influence emission rates. The lower respiratory aerosol emission rates for children indicate a need to consider population demographics when predicting airborne disease transmission risks.KEYWORDS: airborne particlesrespiratory emissionCOVID-19aerosolsbioaerosolstransmissionsuperemitterDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. Additional informationFundingThis work was supported by the National Science Foundation [CBET:2029548] and the Clarkson University COVID-19 Special Solicitation.
{"title":"Comparing respiratory aerosol emissions between children and adults during sustained phonation","authors":"Mahender Singh Rawat, Mehtap Agirsoy, Dinushani Senarathna, Byron D. Erath, Tanvir Ahmed, Sumona Mondal, Andrea R. Ferro","doi":"10.1080/02786826.2023.2261715","DOIUrl":"https://doi.org/10.1080/02786826.2023.2261715","url":null,"abstract":"AbstractRespiratory aerosols arise due to bronchial fluid film bursting within the pulmonary tract, the vibration of the vocal folds during phonation, and articulation of the tongue/lips/teeth. We expect respiratory aerosol emission rates to be lower in children than adults due to the smaller size of their laryngeal structure, reduced sub-glottal pressure created during speech, and reduced number of alveoli. However, few studies have evaluated respiratory aerosols for children. We recruited 50 participants from three age categories: children aged 6−11 years, children aged 12−18 years, and adults ( >18 years). We investigated particle emissions for three different 5 s sustained vocalizations of /a/ or /pa/ at 262 Hz, as well as for running speech and breathing. The particle generation rate ranged from 0 to 488 particles/s. Children aged 6−11 years produced fewer particles (mean 12 ± SD 9 particles/s) than children aged 12−18 years (23 ± 19 particles/s) and adults (70 ± 73 particles/s). Taking a deep breath before vocalizing /a/ resulted in higher aerosol emission rates than the baseline case. The particle number size distributions for all vocalizations and age groups consistently showed two modes at ≈0.6 μm and ≈2 μm. Children had a slightly smaller primary mode location and larger secondary mode location than adults. Superemitters (statistical outliers) were found in all groups. Experiments repeated over time revealed large intrapersonal variability indicating additional variables (e.g., environmental, physiological, behavioral) may significantly influence emission rates. The lower respiratory aerosol emission rates for children indicate a need to consider population demographics when predicting airborne disease transmission risks.KEYWORDS: airborne particlesrespiratory emissionCOVID-19aerosolsbioaerosolstransmissionsuperemitterDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. Additional informationFundingThis work was supported by the National Science Foundation [CBET:2029548] and the Clarkson University COVID-19 Special Solicitation.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-10-16DOI: 10.1080/02786826.2023.2270503
Felipe A. Rivera-Adorno, Jay M. Tomlin, Matthew Fraund, Erick Morgan, Michael Laskin, Ryan Moffet, Alexander Laskin
AbstractAirborne particles alter the radiative forcing of climate and have further consequences on air visibility, atmospheric chemistry, and human health. Recent studies reported the existence of highly viscous semi-solid and even solid amorphous organic aerosol (OA) particles. Particle viscosity has an impact on the heterogeneous chemistry, gas-particle partitioning, and ice nucleation properties. Consequently, variations in particle viscosity must be considered when predicting the atmospheric impact of OA. Here we use scanning electron microscopy (SEM) and scanning transmission X-ray microscopy (STXM) to estimate the viscosity of individual particles deposited on substrates based on their characteristic height-to-width ratios, which are affected by changes in morphology upon deposition. The height-to-width ratios obtained from SEM and STXM exhibit a strong correlation, demonstrating that both imaging approaches can be applied separately for viscosity assessment of the substrate-deposited particles. While these metrics are largely qualitative, this method enables rapid assessment of particle viscosity ranges, distinguishing between semi-solid (>1010 Pa·s), viscous (104-108 Pa·s), and liquid (10°-101 Pa·s) particles within ensembles of ambient particles collected for microscopy studies.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThis work was supported by the U. S. Department of Energy’s (DOE) Atmospheric System Research program, Office of Biological and Environmental Research (OBER), award DE-SC0021977. The SEM imaging for this project was performed at the Life Science Microscope Facility at Purdue University. The STXM imaging was performed at beamline 5.3.2.2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. We thank Mr. Mark Carlsen, instrumentation specialist from Purdue’s Jonathan Amy Facility for Chemical Instrumentation, for assembling the drying system used for particle generation and collection.Author contributionsF.R. and A.L. devised the project. F.R., J.T., M.F., R.M. conducted STXM measurements. F. R. and E.M. conducted laboratory experiments, collected samples of particle standards, performed SEM measurements, analyzed and integrated all datasets. M.L. provided geometry derivations. F.R. and A.L. wrote the manuscript with contributions from all coauthors. The authors report there are no competing interests to declare.
{"title":"Estimating Viscosity of Individual Substrate-Deposited Particles from Measurements of Their Height-to-Width Ratios","authors":"Felipe A. Rivera-Adorno, Jay M. Tomlin, Matthew Fraund, Erick Morgan, Michael Laskin, Ryan Moffet, Alexander Laskin","doi":"10.1080/02786826.2023.2270503","DOIUrl":"https://doi.org/10.1080/02786826.2023.2270503","url":null,"abstract":"AbstractAirborne particles alter the radiative forcing of climate and have further consequences on air visibility, atmospheric chemistry, and human health. Recent studies reported the existence of highly viscous semi-solid and even solid amorphous organic aerosol (OA) particles. Particle viscosity has an impact on the heterogeneous chemistry, gas-particle partitioning, and ice nucleation properties. Consequently, variations in particle viscosity must be considered when predicting the atmospheric impact of OA. Here we use scanning electron microscopy (SEM) and scanning transmission X-ray microscopy (STXM) to estimate the viscosity of individual particles deposited on substrates based on their characteristic height-to-width ratios, which are affected by changes in morphology upon deposition. The height-to-width ratios obtained from SEM and STXM exhibit a strong correlation, demonstrating that both imaging approaches can be applied separately for viscosity assessment of the substrate-deposited particles. While these metrics are largely qualitative, this method enables rapid assessment of particle viscosity ranges, distinguishing between semi-solid (>1010 Pa·s), viscous (104-108 Pa·s), and liquid (10°-101 Pa·s) particles within ensembles of ambient particles collected for microscopy studies.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThis work was supported by the U. S. Department of Energy’s (DOE) Atmospheric System Research program, Office of Biological and Environmental Research (OBER), award DE-SC0021977. The SEM imaging for this project was performed at the Life Science Microscope Facility at Purdue University. The STXM imaging was performed at beamline 5.3.2.2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. We thank Mr. Mark Carlsen, instrumentation specialist from Purdue’s Jonathan Amy Facility for Chemical Instrumentation, for assembling the drying system used for particle generation and collection.Author contributionsF.R. and A.L. devised the project. F.R., J.T., M.F., R.M. conducted STXM measurements. F. R. and E.M. conducted laboratory experiments, collected samples of particle standards, performed SEM measurements, analyzed and integrated all datasets. M.L. provided geometry derivations. F.R. and A.L. wrote the manuscript with contributions from all coauthors. The authors report there are no competing interests to declare.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136079766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-10-10DOI: 10.1080/02786826.2023.2267649
Kevin T. Jansen, Margaret A. Tolbert
AbstractLight-absorbing organic aerosol (brown carbon, BrC) can have a significant impact on the radiative balance of the Earth’s atmosphere. However there are still substantial uncertainties regarding the formation, composition, and radiative properties of BrC. In this study, we conducted laboratory experiments to investigate the pH dependence of BrC formation in both aerosol particles and bulk phase solutions. Using glyoxal, ammonia, and ammonium salts, we generated precursor solutions under varying bulk pH conditions ranging from 0.69 to 8.43. Drying the solutions either in the bulk or aerosol phase resulted in BrC formation. The resulting organic material was analyzed to determine its chemical composition and optical properties. Under the set of conditions investigated here, neutral to basic conditions of relevance to cloud water favored BrC formation for both aerosols and bulk solutions. In contrast, BrC products were formed under acidic conditions only in the aerosol phase. Due to rapid equilibration with the gas phase and evaporative losses of water, the aerosols probed here likely had extremely low pH values, well below the bulk pH of 0.69. By achieving such acidic conditions in the aerosol phase, new acid-catalyzed pathways are possible to form BrC. These findings indicate brown carbon formation is favored at both high and very low pH, and further point to the importance of using aerosol samples in studies of pH dependent chemistry of relevance to the atmosphere.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.
{"title":"Probing the pH dependence of brown carbon formation: Insights from laboratory studies on aerosol particles and bulk phase solutions","authors":"Kevin T. Jansen, Margaret A. Tolbert","doi":"10.1080/02786826.2023.2267649","DOIUrl":"https://doi.org/10.1080/02786826.2023.2267649","url":null,"abstract":"AbstractLight-absorbing organic aerosol (brown carbon, BrC) can have a significant impact on the radiative balance of the Earth’s atmosphere. However there are still substantial uncertainties regarding the formation, composition, and radiative properties of BrC. In this study, we conducted laboratory experiments to investigate the pH dependence of BrC formation in both aerosol particles and bulk phase solutions. Using glyoxal, ammonia, and ammonium salts, we generated precursor solutions under varying bulk pH conditions ranging from 0.69 to 8.43. Drying the solutions either in the bulk or aerosol phase resulted in BrC formation. The resulting organic material was analyzed to determine its chemical composition and optical properties. Under the set of conditions investigated here, neutral to basic conditions of relevance to cloud water favored BrC formation for both aerosols and bulk solutions. In contrast, BrC products were formed under acidic conditions only in the aerosol phase. Due to rapid equilibration with the gas phase and evaporative losses of water, the aerosols probed here likely had extremely low pH values, well below the bulk pH of 0.69. By achieving such acidic conditions in the aerosol phase, new acid-catalyzed pathways are possible to form BrC. These findings indicate brown carbon formation is favored at both high and very low pH, and further point to the importance of using aerosol samples in studies of pH dependent chemistry of relevance to the atmosphere.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136352956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-10-10DOI: 10.1080/02786826.2023.2267689
Alicja Szczepanska, Joshua Harrison, Brian Saccente-Kennedy, Justice Archer, Natalie A. Watson, Christopher M. Orton, William J. Browne, Ruth Epstein, James D. Calder, Pallav L. Shah, Declan Costello, Bryan R. Bzdek, Jonathan P. Reid
AbstractTransmission of an airborne disease can occur when an individual exhales respiratory particles that contain infectious pathogens. Surgical face masks are often used to reduce the amount of respiratory aerosol emitted into the environment by an individual while also lowering the concentration of particles the individual inhales. Respiratory aerosol generation is activity-dependent with high person-to-person variability. Moreover, mask fit differs among people. Here, we measure the efficacy of surgical masks (EN14683 Type IIR) in reducing both aerosol (0.3 – 20 μm diameter) and droplet (20 – 1000 μm diameter) emission during breathing, speaking and five speech and language therapy tasks performed by a human cohort. When participants wore a surgical face mask, measured particle number concentrations at the front of the mask were always lower than that for breathing without mitigation in place. For breathing and speaking, the through-mask filtration efficiencies were 80% and 87%, respectively, while for voice therapy tasks the through-mask filtration efficiencies ranged from 89% (“Hey!”) to 95% (/a::/). Size-dependent through-mask filtration efficiencies were high (80 – 95%) for particles 0.5 – 2 μm diameter, with masks filtering a greater fraction of larger particle sizes. For particle sizes >4 µm diameter, filtration efficiencies of surgical face masks for all tested respiratory tasks were ∼100%. Surgical face masks significantly reduced the number of particles emitted from all respiratory activities. These results have implications for developing effective mitigations for diseases transmission through inhalation.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. ACKNOWLEDGEMENTSThe authors acknowledge funding from the Engineering and Physical Sciences Research Council (EP/V050516/1). B.R.B. acknowledges the Natural Environment Research Council (NE/P018459/1). B.R.B. and A.S. acknowledge funding from the European Research Council (Project 948498, AeroSurf). J.H. acknowledges funding from the EPSRC Centre for Doctoral Training in Aerosol Science (EP/S023593/1). Fortius Surgical Centre, Marylebone, London, is acknowledged for the generous provision of space to conduct the measurements. We thank all our volunteer participants for their contribution to this study.Data AvailabilityData underlying the figures are publicly available in the BioStudies database (https://www.ebi.ac.uk/biostudies/) under accession ID S-BSST1187.The analysed data are provided in Supplemental Information available online.
{"title":"The Filtration Efficiency of Surgical Masks for Expiratory Aerosol and Droplets Generated by Vocal Exercises","authors":"Alicja Szczepanska, Joshua Harrison, Brian Saccente-Kennedy, Justice Archer, Natalie A. Watson, Christopher M. Orton, William J. Browne, Ruth Epstein, James D. Calder, Pallav L. Shah, Declan Costello, Bryan R. Bzdek, Jonathan P. Reid","doi":"10.1080/02786826.2023.2267689","DOIUrl":"https://doi.org/10.1080/02786826.2023.2267689","url":null,"abstract":"AbstractTransmission of an airborne disease can occur when an individual exhales respiratory particles that contain infectious pathogens. Surgical face masks are often used to reduce the amount of respiratory aerosol emitted into the environment by an individual while also lowering the concentration of particles the individual inhales. Respiratory aerosol generation is activity-dependent with high person-to-person variability. Moreover, mask fit differs among people. Here, we measure the efficacy of surgical masks (EN14683 Type IIR) in reducing both aerosol (0.3 – 20 μm diameter) and droplet (20 – 1000 μm diameter) emission during breathing, speaking and five speech and language therapy tasks performed by a human cohort. When participants wore a surgical face mask, measured particle number concentrations at the front of the mask were always lower than that for breathing without mitigation in place. For breathing and speaking, the through-mask filtration efficiencies were 80% and 87%, respectively, while for voice therapy tasks the through-mask filtration efficiencies ranged from 89% (“Hey!”) to 95% (/a::/). Size-dependent through-mask filtration efficiencies were high (80 – 95%) for particles 0.5 – 2 μm diameter, with masks filtering a greater fraction of larger particle sizes. For particle sizes >4 µm diameter, filtration efficiencies of surgical face masks for all tested respiratory tasks were ∼100%. Surgical face masks significantly reduced the number of particles emitted from all respiratory activities. These results have implications for developing effective mitigations for diseases transmission through inhalation.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. ACKNOWLEDGEMENTSThe authors acknowledge funding from the Engineering and Physical Sciences Research Council (EP/V050516/1). B.R.B. acknowledges the Natural Environment Research Council (NE/P018459/1). B.R.B. and A.S. acknowledge funding from the European Research Council (Project 948498, AeroSurf). J.H. acknowledges funding from the EPSRC Centre for Doctoral Training in Aerosol Science (EP/S023593/1). Fortius Surgical Centre, Marylebone, London, is acknowledged for the generous provision of space to conduct the measurements. We thank all our volunteer participants for their contribution to this study.Data AvailabilityData underlying the figures are publicly available in the BioStudies database (https://www.ebi.ac.uk/biostudies/) under accession ID S-BSST1187.The analysed data are provided in Supplemental Information available online.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136294797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-10-09DOI: 10.1080/02786826.2023.2262004
Katherine M. Ratliff, Lukas Oudejans, John Archer, Worth Calfee, Jerome U. Gilberry, David Adam Hook, William E. Schoppman, Robert W. Yaga, Lance Brooks, Shawn Ryan
AbstractThe COVID-19 pandemic has raised interest in using chemical air treatments as part of a strategy to reduce the risk of disease transmission, but more information is needed to characterize their efficacy at scales translatable to applied settings and to develop standardized test methods for characterizing the performance of these products. Grignard Pure, a triethylene glycol (TEG) active ingredient air treatment, was evaluated using two different test protocols in a large bioaerosol test chamber and observed to inactivate bacteriophage MS2 in air (up to 99.9% at 90 minutes) and on surfaces (up to 99% at 90 minutes) at a concentration of approximately 1.2 – 1.5 mg/m3. Introducing bioaerosol into a TEG-charged chamber led to overall greater reductions compared to when TEG was introduced into a bioaerosol-charged chamber, although the differences in efficacy against airborne MS2 were only significant in the first 15 minutes. Time-matched control conditions (no TEG present) and replicate tests for each condition were essential for characterizing treatment efficacy. These findings suggest that chemical air treatments could be effective in reducing the air and surface concentrations of infectious pathogens in occupied spaces, although standard methods are needed for evaluating their efficacy and comparing results across studies. The potential health impacts of chronic exposure to chemicals should also be considered, but those were not evaluated here.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThe authors gratefully acknowledge members of the EPA Project Team, the members of Jacobs Technology, Inc. (JTI) supporting the EPA Homeland Security and Materials Management Microbiology lab and the JTI Aerosol Science Team, Adam Burdsall and Marc Carpenter for internal technical reviews of this manuscript, and Ramona Sherman and for quality assurance support.DisclaimerThe EPA, through its Office of Research and Development, directed the research described herein conducted through contract 68HERC20D0018 with Jacobs Technology, Inc. It has been subjected to the Agency's review and has been approved for publication. Mention of trade names, products or services does not convey official EPA approval, endorsement, or recommendation.Declaration of InterestsThe authors report there are no competing interests to declare.Data AvailabilityThe data that support the findings of this study are openly available at https://doi.org/10.23719/1528421.
{"title":"Impact of Test Methodology on the Efficacy of Triethylene Glycol (Grignard Pure) against Bacteriophage MS2","authors":"Katherine M. Ratliff, Lukas Oudejans, John Archer, Worth Calfee, Jerome U. Gilberry, David Adam Hook, William E. Schoppman, Robert W. Yaga, Lance Brooks, Shawn Ryan","doi":"10.1080/02786826.2023.2262004","DOIUrl":"https://doi.org/10.1080/02786826.2023.2262004","url":null,"abstract":"AbstractThe COVID-19 pandemic has raised interest in using chemical air treatments as part of a strategy to reduce the risk of disease transmission, but more information is needed to characterize their efficacy at scales translatable to applied settings and to develop standardized test methods for characterizing the performance of these products. Grignard Pure, a triethylene glycol (TEG) active ingredient air treatment, was evaluated using two different test protocols in a large bioaerosol test chamber and observed to inactivate bacteriophage MS2 in air (up to 99.9% at 90 minutes) and on surfaces (up to 99% at 90 minutes) at a concentration of approximately 1.2 – 1.5 mg/m3. Introducing bioaerosol into a TEG-charged chamber led to overall greater reductions compared to when TEG was introduced into a bioaerosol-charged chamber, although the differences in efficacy against airborne MS2 were only significant in the first 15 minutes. Time-matched control conditions (no TEG present) and replicate tests for each condition were essential for characterizing treatment efficacy. These findings suggest that chemical air treatments could be effective in reducing the air and surface concentrations of infectious pathogens in occupied spaces, although standard methods are needed for evaluating their efficacy and comparing results across studies. The potential health impacts of chronic exposure to chemicals should also be considered, but those were not evaluated here.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThe authors gratefully acknowledge members of the EPA Project Team, the members of Jacobs Technology, Inc. (JTI) supporting the EPA Homeland Security and Materials Management Microbiology lab and the JTI Aerosol Science Team, Adam Burdsall and Marc Carpenter for internal technical reviews of this manuscript, and Ramona Sherman and for quality assurance support.DisclaimerThe EPA, through its Office of Research and Development, directed the research described herein conducted through contract 68HERC20D0018 with Jacobs Technology, Inc. It has been subjected to the Agency's review and has been approved for publication. Mention of trade names, products or services does not convey official EPA approval, endorsement, or recommendation.Declaration of InterestsThe authors report there are no competing interests to declare.Data AvailabilityThe data that support the findings of this study are openly available at https://doi.org/10.23719/1528421.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135044326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-10-06DOI: 10.1080/02786826.2023.2265954
Kevin Axelrod, Chiranjivi Bhattarai, Palina Bahdanovich, Vera Samburova, Andrey Y. Khlystov
The volatility of organic aerosol in the atmosphere is an important quality that determines the aerosol/gas partitioning of compounds in the atmosphere and thus influences their ability to participate in gas-phase reactions in the atmosphere. In this research, the volatility of biological aerosols, specifically water-soluble pollen extracts and their chemical constituents, are studied for important thermodynamic properties such as saturation vapor concentration and latent heat of vaporization. The integrated volume method (IVM) was applied to characterize these properties for various free amino acids and saccharides in pollen, and the volatility basis set (VBS) approach was utilized to obtain a distribution of the mass fraction of pollen extracts with respect to saturation vapor concentration. Our results indicate that among seven compounds tested with the IVM, proline, γ-aminobutyric acid, and fructose had semivolatile saturation vapor concentrations of 17.5 ± 2.2, 14.7 ± 0.8, and 4.4 ± 0.5 μg m−3, respectively. Additionally, our VBS measurements indicate that aspen pollen extract contains a greater semivolatile mass fraction (up to 8.5% of total water-soluble mass) than lodgepole pine pollen (up to 2.2%), indicating that different pollen species may contribute to the total atmospheric semivolatile organic compound (SVOC) and low volatile organic compound (LVOC) budget differently. Depending on estimates of several factors, fluxes and concentrations of SVOCs and LVOCs from pollen could be comparable to other sources such as biomass burning and ambient urban emissions, though further research is needed to better constrain the contribution of pollen and other bioaerosols to organic compounds in the atmosphere.
{"title":"The volatility of pollen extracts and their main constituents in aerosolized form via the integrated volume method (IVM) and the volatility basis set (VBS)","authors":"Kevin Axelrod, Chiranjivi Bhattarai, Palina Bahdanovich, Vera Samburova, Andrey Y. Khlystov","doi":"10.1080/02786826.2023.2265954","DOIUrl":"https://doi.org/10.1080/02786826.2023.2265954","url":null,"abstract":"The volatility of organic aerosol in the atmosphere is an important quality that determines the aerosol/gas partitioning of compounds in the atmosphere and thus influences their ability to participate in gas-phase reactions in the atmosphere. In this research, the volatility of biological aerosols, specifically water-soluble pollen extracts and their chemical constituents, are studied for important thermodynamic properties such as saturation vapor concentration and latent heat of vaporization. The integrated volume method (IVM) was applied to characterize these properties for various free amino acids and saccharides in pollen, and the volatility basis set (VBS) approach was utilized to obtain a distribution of the mass fraction of pollen extracts with respect to saturation vapor concentration. Our results indicate that among seven compounds tested with the IVM, proline, γ-aminobutyric acid, and fructose had semivolatile saturation vapor concentrations of 17.5 ± 2.2, 14.7 ± 0.8, and 4.4 ± 0.5 μg m−3, respectively. Additionally, our VBS measurements indicate that aspen pollen extract contains a greater semivolatile mass fraction (up to 8.5% of total water-soluble mass) than lodgepole pine pollen (up to 2.2%), indicating that different pollen species may contribute to the total atmospheric semivolatile organic compound (SVOC) and low volatile organic compound (LVOC) budget differently. Depending on estimates of several factors, fluxes and concentrations of SVOCs and LVOCs from pollen could be comparable to other sources such as biomass burning and ambient urban emissions, though further research is needed to better constrain the contribution of pollen and other bioaerosols to organic compounds in the atmosphere.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135346720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-10-06DOI: 10.1080/02786826.2023.2265454
Thi-Cuc Le, Pallavi Gajanan Barhate, Kai-Jing Zhen, Manisha Mishra, David. Y. H. Pui, Chuen-Jinn Tsai
ABSTRACTThe accurate measurement of PM2.5 and its inorganic matters (IMs) is crucial for compliance monitoring and understanding particle formation. However, semi-volatile IMs (SVIMs) like NH4+, NO3− and Cl− tend to evaporate from particles, causing sampling artifacts. The evaporation loss occurs due to many factors making the quantitative prediction difficult. This study aimed to investigate the evaporation loss of SVIMs in PM2.5 under different sampling conditions. In the field tests, when a normal single Teflon filter sampler (STF), which is like a Federal Reference Method (FRM) sampler, was used to sample PM2.5 at ambient conditions, a significant SVIM evaporation loss was observed, resulting in negative biases for total IMs (-25.68 ± 3.25%) and PM2.5 concentrations (-9.87 ± 4.27%). But if PM2.5 was sampled by a chilled Teflon filter sampler (CTF) at 4 0C following aerosol dehumidification so that relative humidity (RH) was controlled to within the 10-20% range (RHd), evaporation loss was minimized with a bias of < ±10% for both total IMs and PM2.5 based on the reference data. When RHd is below 10%, both IMs and PM2.5 are under-measured, but only PM2.5 is over-measured when RHd is >20%. A model considering predictable saturation ratios for NH4+, NO3− and Cl− under various pressure drop, temperature and RH conditions was developed to predict accurately the actual concentrations of PM2.5 and its SVIMs for the STF. Additionally, the ISORROPIA-II model predicted SVIMs effectively for the CTF. In summary, using the CTF at optimized sampling conditions can achieve accurate measurement of both SVIMs and PM2.5 concentrations simultaneously.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThis work was supported by the Ministry of Science and Technology, Taiwan (contract MOST 111-2221-E-A49-057-MY3), the Ministry of Education, the Higher Education Sprout Project of National Yang Ming Chiao Tung University, and the Academic-Industry Research Hub of People and Earth (AIR HoPE).Disclosure statementThe authors report there are no competing interests to declare.
{"title":"Optimization of sampling conditions to minimize sampling errors of both PM <sub>2.5</sub> mass and its semi-volatile inorganic ion concentrations","authors":"Thi-Cuc Le, Pallavi Gajanan Barhate, Kai-Jing Zhen, Manisha Mishra, David. Y. H. Pui, Chuen-Jinn Tsai","doi":"10.1080/02786826.2023.2265454","DOIUrl":"https://doi.org/10.1080/02786826.2023.2265454","url":null,"abstract":"ABSTRACTThe accurate measurement of PM2.5 and its inorganic matters (IMs) is crucial for compliance monitoring and understanding particle formation. However, semi-volatile IMs (SVIMs) like NH4+, NO3− and Cl− tend to evaporate from particles, causing sampling artifacts. The evaporation loss occurs due to many factors making the quantitative prediction difficult. This study aimed to investigate the evaporation loss of SVIMs in PM2.5 under different sampling conditions. In the field tests, when a normal single Teflon filter sampler (STF), which is like a Federal Reference Method (FRM) sampler, was used to sample PM2.5 at ambient conditions, a significant SVIM evaporation loss was observed, resulting in negative biases for total IMs (-25.68 ± 3.25%) and PM2.5 concentrations (-9.87 ± 4.27%). But if PM2.5 was sampled by a chilled Teflon filter sampler (CTF) at 4 0C following aerosol dehumidification so that relative humidity (RH) was controlled to within the 10-20% range (RHd), evaporation loss was minimized with a bias of < ±10% for both total IMs and PM2.5 based on the reference data. When RHd is below 10%, both IMs and PM2.5 are under-measured, but only PM2.5 is over-measured when RHd is >20%. A model considering predictable saturation ratios for NH4+, NO3− and Cl− under various pressure drop, temperature and RH conditions was developed to predict accurately the actual concentrations of PM2.5 and its SVIMs for the STF. Additionally, the ISORROPIA-II model predicted SVIMs effectively for the CTF. In summary, using the CTF at optimized sampling conditions can achieve accurate measurement of both SVIMs and PM2.5 concentrations simultaneously.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgementsThis work was supported by the Ministry of Science and Technology, Taiwan (contract MOST 111-2221-E-A49-057-MY3), the Ministry of Education, the Higher Education Sprout Project of National Yang Ming Chiao Tung University, and the Academic-Industry Research Hub of People and Earth (AIR HoPE).Disclosure statementThe authors report there are no competing interests to declare.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135346718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-10-05DOI: 10.1080/02786826.2023.2266494
Ana C. Morales, Brianna N. Peterson, Steven A. Sharpe, Shelby M. Huston, Jay M. Tomlin, Felipe A. Rivera-Adorno, Ryan C. Moffet, Alla Zelenyuk, Alexander Laskin
AbstractDistinguishing highly viscous organic particles within complex mixtures of atmospheric aerosol and accurate descriptions of their composition, size distributions, and mixing states are challenges at the forefront of aerosol measurement science and technology. Here, we present results obtained from complementary single-particle measurement techniques employed for the in-depth characterization of highly viscous particles. We demonstrate advantages and synergy of this multi-modal particle characterization approach based on the analysis of individual viscous particles formed in the air-discharged waste produced by a common sewer pipe rehabilitation technology. Using oil immersion flow microscopy, we investigate particle size distributions and morphology of colloidal components present in field-collected aqueous waste condensates. We compare these results with corresponding measurements of viscous particles formed in drying droplets of the aerosolized discharged waste. The colloidal components and viscous particles were found to be approximately 10 µm and 0.5 µm, respectively. The aerosolized viscous particles exhibited a spherical morphology, while the colloidal particles appeared noticeably fractal, resembling fragments of a cured composite material. Chemical imaging of the viscous particles collected on substrates was performed using scanning electron microscopy and soft X-ray spectro-microscopy techniques. Through these methods, comprehensive description of these particles emerged, confirming their high solid-like viscosity, wide-ranging sizes, diverse carbon speciation with high degrees of oxygenation, and high organic volume fractions. The aerosolized viscous particles were further characterized using high-throughput single particle mass spectrometry. This technique provides real-time measurements of composition, size, and morphological metrics for large numbers of individual particles, enabling the identification of their distinct mass spectrometric signatures.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.
{"title":"Multi-modal Chemical Characterization of Highly Viscous Submicrometer Organic Particles.","authors":"Ana C. Morales, Brianna N. Peterson, Steven A. Sharpe, Shelby M. Huston, Jay M. Tomlin, Felipe A. Rivera-Adorno, Ryan C. Moffet, Alla Zelenyuk, Alexander Laskin","doi":"10.1080/02786826.2023.2266494","DOIUrl":"https://doi.org/10.1080/02786826.2023.2266494","url":null,"abstract":"AbstractDistinguishing highly viscous organic particles within complex mixtures of atmospheric aerosol and accurate descriptions of their composition, size distributions, and mixing states are challenges at the forefront of aerosol measurement science and technology. Here, we present results obtained from complementary single-particle measurement techniques employed for the in-depth characterization of highly viscous particles. We demonstrate advantages and synergy of this multi-modal particle characterization approach based on the analysis of individual viscous particles formed in the air-discharged waste produced by a common sewer pipe rehabilitation technology. Using oil immersion flow microscopy, we investigate particle size distributions and morphology of colloidal components present in field-collected aqueous waste condensates. We compare these results with corresponding measurements of viscous particles formed in drying droplets of the aerosolized discharged waste. The colloidal components and viscous particles were found to be approximately 10 µm and 0.5 µm, respectively. The aerosolized viscous particles exhibited a spherical morphology, while the colloidal particles appeared noticeably fractal, resembling fragments of a cured composite material. Chemical imaging of the viscous particles collected on substrates was performed using scanning electron microscopy and soft X-ray spectro-microscopy techniques. Through these methods, comprehensive description of these particles emerged, confirming their high solid-like viscosity, wide-ranging sizes, diverse carbon speciation with high degrees of oxygenation, and high organic volume fractions. The aerosolized viscous particles were further characterized using high-throughput single particle mass spectrometry. This technique provides real-time measurements of composition, size, and morphological metrics for large numbers of individual particles, enabling the identification of their distinct mass spectrometric signatures.DisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134974972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-09-26DOI: 10.1080/02786826.2023.2256827
Meredith Schervish, Neil M Donahue, Manabu Shiraiwa
Different populations of aerosol are constantly mixed throughout the atmosphere. Large-scale models often assume no particle–particle mixing or fast mixing among aerosol populations, so that they stay externally mixed or instantaneously form internal mixtures. We apply the kinetic multilayer model of gas–particle interactions (KM-GAP) to simulate the evaporation of semi-volatile species from one particle population and partitioning into another population with various phase states and nonideal mixing conditions. We find that the particle–particle mixing timescale (τmix) is prolonged when the semi-volatile species transport to a population in which it is miscible, as more mass must be transported. Extremes of volatility prolong the τmix, as low-volatility species evaporate slowly, while high-volatility species condense slowly. When the bulk diffusivities of the two populations are greater than 10−15 cm2 s−1, semi-volatile species mix rapidly; otherwise, the τmix can be prolonged beyond 1 h. We apply KM-GAP to particle–particle mixing experiments of H-toluene SOA into D-toluene SOA and limonene SOA, showing that τmix is prolonged when toluene SOA is highly viscous, while initial partitioning of gas phase semi-volatile species from toluene SOA into limonene SOA is rapid because of the low viscosity of limonene SOA. Simulations of mixing toluene SOA and β-caryophyllene SOA indicate that the apparent discrepancy of limited mixing under conditions where both are predicted to have low viscosity are explained by limited miscibility of the semi-volatile components. Our study demonstrates that particle–particle mixing timescales are affected by a complex interplay among volatility, diffusion limitations, and non-ideal miscibility.
{"title":"Effects of volatility, viscosity, and non-ideality on particle–particle mixing timescales of secondary organic aerosols","authors":"Meredith Schervish, Neil M Donahue, Manabu Shiraiwa","doi":"10.1080/02786826.2023.2256827","DOIUrl":"https://doi.org/10.1080/02786826.2023.2256827","url":null,"abstract":"Different populations of aerosol are constantly mixed throughout the atmosphere. Large-scale models often assume no particle–particle mixing or fast mixing among aerosol populations, so that they stay externally mixed or instantaneously form internal mixtures. We apply the kinetic multilayer model of gas–particle interactions (KM-GAP) to simulate the evaporation of semi-volatile species from one particle population and partitioning into another population with various phase states and nonideal mixing conditions. We find that the particle–particle mixing timescale (τmix) is prolonged when the semi-volatile species transport to a population in which it is miscible, as more mass must be transported. Extremes of volatility prolong the τmix, as low-volatility species evaporate slowly, while high-volatility species condense slowly. When the bulk diffusivities of the two populations are greater than 10−15 cm2 s−1, semi-volatile species mix rapidly; otherwise, the τmix can be prolonged beyond 1 h. We apply KM-GAP to particle–particle mixing experiments of H-toluene SOA into D-toluene SOA and limonene SOA, showing that τmix is prolonged when toluene SOA is highly viscous, while initial partitioning of gas phase semi-volatile species from toluene SOA into limonene SOA is rapid because of the low viscosity of limonene SOA. Simulations of mixing toluene SOA and β-caryophyllene SOA indicate that the apparent discrepancy of limited mixing under conditions where both are predicted to have low viscosity are explained by limited miscibility of the semi-volatile components. Our study demonstrates that particle–particle mixing timescales are affected by a complex interplay among volatility, diffusion limitations, and non-ideal miscibility.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134886879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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