83 results match your criteria Aerosol Science And Technology[Journal]

Influence of Ash-Soot Interactions on the Reactivity of Soot from a Gasoline Direct Injection Engine.

Aerosol Sci Technol 2020 ;54(12):1373-1385

Mechanical Engineering, University of Michigan, Ann Arbor, Mi, USA.

Gasoline particulate filters (GPF) are being utilized in certain markets on gasoline direct injection (GDI) vehicles to reduce tailpipe particulate emissions as required by particle number regulations. GPF filtration efficiency is dependent on soot build-up within the filter. Since soot oxidizes within the GPF during normal vehicle operation, an understanding of soot reactivity is important for optimizing aftertreatment architecture and engine calibration. Read More

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January 2020

Coupling an online ion conductivity measurement with the particle-into-liquid sampler: Evaluation and modeling using laboratory and field aerosol data.

Aerosol Sci Technol 2020 12;54(12):1542-1555. Epub 2020 Aug 12.

Science Systems and Applications, Inc., Hampton, Virginia, USA.

A particle-into-liquid sampler (PILS) was coupled to a flow-through conductivity cell to provide a continuous, nondestructive, online measurement in support of offline ion chromatography analysis. The conductivity measurement provides a rapid assessment of the total ion concentration augmenting slower batch-sample data from offline analysis and is developed primarily to assist airborne measurements, where fast time-response is essential. A conductivity model was developed for measured ions and excellent closure was derived for laboratory-generated aerosols (97% conductivity explained, R > 0. Read More

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Effects of propylene glycol, vegetable glycerin, and nicotine on emissions and dynamics of electronic cigarette aerosols.

Aerosol Sci Technol 2020 8;54(11):1270-1281. Epub 2020 Jun 8.

Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, California, USA.

An electronic cigarette (e-cig) generates aerosols by vaporizing the e-liquid, which mainly consists of propylene glycol (PG), vegetable glycerin (VG), and nicotine. Understanding the effects of e-liquid main compositions on e-cig aerosols is important for exposure assessment. This study investigated how the PG/VG ratio and nicotine content affect e-cig aerosol emissions and dynamics. Read More

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Assessment and Validation of a Hygroscopic Growth Model with Different Water Activity Estimation Methods.

Aerosol Sci Technol 2020 19;54(10):1169-1182. Epub 2020 May 19.

Mechanical Engineering, University of Iowa, Iowa City, Iowa, USA.

Hygroscopic growth models are currently of interest as aids for targeting the deposition of inhaled drug particles in preferred areas of the lung that will maximize their pharmaceutical effect. Mathematical models derived to estimate hygroscopic growth over time have been previously developed but have not been thoroughly validated. For this study, model validation involved a comparison of modeled values to measured values when the growing droplet had reached equilibrium. Read More

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The coronavirus pandemic and aerosols: Does COVID-19 transmit via expiratory particles?

Aerosol Sci Technol 2020 3;0(0):1-4. Epub 2020 Apr 3.

Department of Chemical Engineering, Davis College of Engineering, University of California, Davis, California, USA.

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Field sampling of indoor bioaerosols.

Aerosol Sci Technol 2020 21;54(5):572-584. Epub 2019 Nov 21.

Department of Biochemistry, Microbiology, and Bioinformatics, Université Laval, Québec, Canada.

Because bioaerosols are related to adverse health effects in exposed humans and indoor environments represent a unique framework of exposure, concerns about indoor bioaerosols have risen over recent years. One of the major issues in indoor bioaerosol research is the lack of standardization in the methodology, from air sampling strategies and sample treatment to the analytical methods applied. The main characteristics to consider in the choice of indoor sampling methods for bioaerosols are the sampler performance, the representativeness of the sampling, and the concordance with the analytical methods to be used. Read More

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November 2019

Electrochemical Dithiothreitol Assay for Large-Scale Particulate Matter Studies.

Aerosol Sci Technol 2019 24;53(3):268-275. Epub 2019 Jan 24.

Dept of Chemistry, Colorado State University.

Particulate matter (PM) air pollution is associated with human morbidity and mortality. Measuring PM oxidative potential has been shown to provide a predictive measurement between PM exposure and adverse health impacts. The dithiothreitol (DTT) assay is commonly used to measure the oxidative potential of PM (PM less than 2. Read More

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January 2019

Simultaneous transmission and absorption photometry of carbon-black absorption from drop-cast particle-laden filters.

Aerosol Sci Technol 2019 ;53

Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, USA.

Simultaneous transmissivity and absorptivity measurements were carried out in the visible at a laser wavelength of 532 nm on drop-cast, carbon-black-laden filters under ambient (laboratory) conditions. The focus of this investigation was to establish the feasibility of this approach to estimate the mass absorption coefficient of the isolated particles and compare results to earlier work with the same carbon-black source. Transmissivity measurements were carried out with a laser probe beam positioned normal to the particle-laden filter surface. Read More

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January 2019

Determination of the distribution of infectious viruses in aerosol particles using water-based condensational growth technology and a bacteriophage MS2 model.

Aerosol Sci Technol 2019 19;53(5):583-593. Epub 2019 Mar 19.

Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, Florida, USA.

Inhalation of aerosols containing pathogenic viruses can result in morbidity, in some cases leading to mortality. The objective of this study was to develop a model for assessing how infectious viruses might distribute in airborne particles using bacteriophage MS2 as a surrogate for human viruses. Particle deposition in the respiratory system is size-dependent, and small virus-containing particles can be inhaled deeply into the lower lungs, potentially leading to more severe respiratory disease manifestations. Read More

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Collection of soot particles into aqueous suspension using a particle-into-liquid sampler.

Aerosol Sci Technol 2019 6;53(1):21-28. Epub 2018 Dec 6.

University of Vienna, Faculty of Physics, Vienna, Austria.

Steam collection devices collecting aerosol particles into liquid samples are frequently used to analyze water-soluble particulate material. The fate of water-insoluble components is often neglected. In this work, we show that fresh soot particles can be suspended into pure water using a steam collection device, the particle-into-liquid sampler (PILS, Weber et al. Read More

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December 2018

Generation of High Concentrations of Respirable Solid-Phase Aerosols from Viscous Fluids.

Aerosol Sci Technol 2018 30;52(8):933-952. Epub 2018 Jul 30.

KAER Biotherapeutics, 926 Andreasen Drive, Suite 105, Escondido, California, USA.

High outputs of respirable solid-phase aerosols were generated from viscous solutions or suspensions of low and high molecular weight polyvinylprrolidone (PVP) solutions, 10% (w/v) albumin and, gamma-globulin solutions as well as 10.3% (w/v) surfactant suspensions. A central fluid flow was aerosolized by coaxial converging compressed air. Read More

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Dihydroxyacetone levels in electronic cigarettes: Wick temperature and toxin formation.

Aerosol Sci Technol 2018 23;52(4):370-376. Epub 2018 Jan 23.

Department of Chemistry, Portland State University, Portland, Oregon, USA.

Recently, we reported the presence of dihydroxyacetone (DHA), the active ingredient in sunless tanners, in the aerosol of an electronic cigarette. DHA has been shown to react with DNA . The FDA restricts the use of DHA to external application only. Read More

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January 2018

Chemical Characterization of Nanoparticles and Volatiles Present in Mainstream Hookah Smoke.

Aerosol Sci Technol 2019 24;53(9):1023-1039. Epub 2019 Jun 24.

Department of Chemistry, University of California, Irvine, California, USA.

Waterpipe smoking is becoming more popular worldwide and there is a pressing need to better characterize the exposure of smokers to chemical compounds present in the mainstream smoke. We report real-time measurements of mainstream smoke for carbon monoxide, volatile organic compounds and nanoparticle size distribution and chemical composition using a custom dilution flow tube. A conventional tobacco mixture, a dark leaf unwashed tobacco and a nicotine-free herbal tobacco were studied. Read More

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Condensational particle growth device for reliable cell exposure at the air-liquid interface to nanoparticles.

Aerosol Sci Technol 2019 16;53(12):1415-1428. Epub 2019 Sep 16.

Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, Florida, USA.

A first-of-its-kind aerosol exposure device for toxicity testing, referred to as the Dosimetric Aerosol Inhalation Device (DAVID), was evaluated for its ability to deliver airborne nanoparticles to lung cells grown as air-liquid interface (ALI) cultures. For inhalation studies, ALI lung cell cultures exposed to airborne nanoparticles have more relevancy than the same cells exposed in submerged culture because ALI culture better represents the respiratory physiology and consequently more closely reflect cellular response to aerosol exposure. In DAVID, water condensation grows particles as small as 5 nm to droplets sized > 5 μm for inertial deposition at low flow rates. Read More

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September 2019

Computational Analysis of Deposition and Translocation of Inhaled Nicotine and Acrolein in the Human Body with E-cigarette Puffing Topographies.

Aerosol Sci Technol 2018 26;52(5):483-493. Epub 2018 Mar 26.

Zhejiang University of Science and Technology, Hangzhou, 310023, China.

Recently, toxicants such as formaldehyde and acrolein were detected in electronic cigarette (EC) aerosols. It is imperative to conduct research and provide sufficient quantitative evidence to address the associated potential health risks. However, it is still a lack of informative data, i. Read More

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Fate of pyrazines in the flavored liquids of e-cigarettes.

Aerosol Sci Technol 2018 21;52(4):377-384. Epub 2018 Feb 21.

American University of Beirut, Lebanon, Chemistry Department, Faculty of Arts and Sciences.

Popularity of electronic cigarettes (ECIGs) has increased tremendously among young people, in part due to flavoring additives in ECIG liquids. Pyrazines are an important class of these additives, and their presence in tobacco cigarettes has been correlated with increased acceptability of smoking among smokers and bystanders. Pyrazine use by the tobacco industry is therefore thought to encourage smoking. Read More

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February 2018

Size-Selective Sampling Performance of Six Low-Volume "Total" Suspended Particulate (TSP) Inlets.

Aerosol Sci Technol 2018 ;52(1):98-113

Alion Science and Technology, 1000 Park Forty Plaza #200, Durham, NC 27713.

Several low-volume inlets (flow rates ≤16.7 liters per minute (Lpm)) are commercially available as components of low-cost, portable ambient particulate matter samplers. Because the inlets themselves do not contain internal fractionators, they are often assumed to representatively sample "total" mass concentrations from the ambient air, independent of aerodynamic particle size and wind speed. Read More

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January 2018

Aerosol size distribution measurement of electronic cigarette emissions using combined differential mobility and inertial impaction methods: Smoking machine and puff topography influence.

Aerosol Sci Technol 2018 14;52(11):1233-1248. Epub 2018 Sep 14.

University of Maryland, College Park, Maryland, USA.

A combination of a real-time high resolution aerosol differential mobility spectrometer (DMS500) and an electrical low pressure impactor (used as a traditional impactor) was applied to simultaneously collect real-time data and analyze particle size by weighing the mass of the aerosol collected on the impactor stages. Nonrefillable fixed-power as well as refillable and power adjustable e-cigarettes (e-cigs) were tested at various puffing flow rates. Two types of smoking machines were used: a smoke cycle simulator that provides instantaneous straight sample delivery to the analyzer and a Human Profile Pump that utilizes two synchronized pistons and operates by sample pull-push mode. Read More

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September 2018

Surgical Smoke Simulation Study: Physical Characterization and Respiratory Protection.

Aerosol Sci Technol 2018 29;52(1):38-45. Epub 2017 Sep 29.

Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, PO Box 670056, Cincinnati, OH, USA.

Exposure of operating room (OR) personnel to surgical smoke, a unique aerosol generated from the common use of electrocautery during surgical procedures, is an increasing health risk concern. The main objective of this simulation study was to characterize the surgical smoke exposure in terms of the particle number concentration and size distribution in a human breathing zone. Additionally, the performance of respiratory protective devices designed for ORs was examined using two commercially available N95 facepiece filtering respirators (FFRs) as well as the same FFRs modified with new faceseal technology. Read More

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September 2017

Trends in the oxidation and relative volatility of chamber-generated secondary organic aerosol.

Aerosol Sci Technol 2018 ;52(9):992-1004

United States Environmental Protection Agency, Office of Research and Development, Research Triangle Park, Durham, North Carolina, USA.

The relationship between the oxidation state and relative volatility of secondary organic aerosol (SOA) from the oxidation of a wide range of hydrocarbons is investigated using a fast-stepping, scanning thermodenuder interfaced with a high-resolution time-of-flight aerosol mass spectrometer (AMS). SOA oxidation state varied widely across the investigated range of parent hydrocarbons but was relatively stable for replicate experiments using a single hydrocarbon precursor. On average, unit mass resolution indicators of SOA oxidation (e. Read More

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January 2018

Electronic cigarette-generated aldehydes: The contribution of e-liquid components to their formation and the use of urinary aldehyde metabolites as biomarkers of exposure.

Aerosol Sci Technol 2018 23;52(11):1219-1232. Epub 2018 Aug 23.

American Heart Association - Tobacco Regulation and Addiction Center, University of Louisville, Louisville, KY 40292.

Electronic cigarettes (e-cigarette) have emerged as a popular electronic nicotine delivery system (ENDS) in the last decade. Despite the absence of combustion products and toxins such as carbon monoxide (CO) and tobacco-specific nitrosamines (TSNA), carbonyls including short-chain, toxic aldehydes have been detected in e-cigarette-derived aerosols up to levels found in tobacco smoke. Given the health concerns regarding exposures to toxic aldehydes, understanding both aldehyde generation in e-cigarette and e-cigarette exposure is critical. Read More

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Rapid Analysis of the Size Distribution of Metal-Containing Aerosol.

Aerosol Sci Technol 2017;51(1):108-115. Epub 2016 Oct 20.

Department of Occupational and Environmental Health, University of Iowa, Iowa.

Conventional methods to measure the metallic content of particles by size are time consuming and expensive, requiring collection of particles with a cascade impactor and subsequent metals analysis by inductively coupled plasma mass spectrometry (ICP-MS). In this work, we describe a rapid way to measure the size distribution of metal-containing particles from 10 nm to 20 μm, using a nano micro-orifice uniform-deposit impactor (nano-MOUDI) to size-selective and collect particles that are then analyzed with a field portable X-ray fluorescence (FP-XRF) to determine metal composition and concentration. The nano-MOUDI was used to sample a stainless-steel aerosol produced by a spark discharge system. Read More

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October 2016

Production of neutral molecular clusters by controlled neutralization of mobility standards.

Aerosol Sci Technol 2017 Aug 8;51(8):946-955. Epub 2017 May 8.

Department of Physics, University of Helsinki, Helsinki, Finland.

Measuring aerosols and molecular clusters below the 3 nm size limit is essential to increase our understanding of new particle formation. Instruments for the detection of sub-3 nm aerosols and clusters exist and need to be carefully calibrated and characterized. So far calibrations and laboratory tests have been carried out using mainly electrically charged aerosols, as they are easier to handle experimentally. Read More

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Transport phenomena governing nicotine emissions from electronic cigarettes: model formulation and experimental investigation.

Aerosol Sci Technol 2017;51(1):1-11. Epub 2016 Nov 8.

Mechanical Engineering Department, Faculty of Engineering and Architecture, American University of Beirut, Beirut, Lebanon.

Electronic cigarettes (ECIGs) electrically heat and aerosolize a liquid containing propylene glycol (PG), vegetable glycerin (VG), flavorants, water, and nicotine. ECIG effects and proposed methods to regulate them are controversial. One regulatory focal point involves nicotine emissions. Read More

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November 2016

Absorption/Transmission Measurements of PSAP Particle-Laden Filters from the Biomass Burning Observation Project (BBOP) Field Campaign.

Aerosol Sci Technol 2017;51(4):451-466. Epub 2016 Dec 2.

Pacific Northwest National Laboratory.

Absorptivity measurements with a laser-heating approach, referred to as the laser-driven thermal reactor (LDTR), were carried out in the infrared and applied at ambient (laboratory) non-reacting conditions to particle-laden filters from a three-wavelength (visible) particle/soot absorption photometer (PSAP). The particles were obtained during the Biomass Burning Observation Project (BBOP) field campaign. The focus of this study was to determine the particle absorption coefficient from field-campaign filter samples using the LDTR approach, and compare results with other commercially available instrumentation (in this case with the PSAP, which has been compared with numerous other optical techniques). Read More

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December 2016

Near-Real Time Measurement of Carbonaceous Aerosol Using Microplasma Spectroscopy: Application to Measurement of Carbon Nanomaterials.

Aerosol Sci Technol 2016 08;50(11):1155-1166

Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, 45221.

A sensitive, field-portable microplasma spectroscopy method has been developed for real-time measurement of carbon nanomaterials. The method involves microconcentration of aerosol on a microelectrode tip for subsequent analysis for atomic carbon using laser-induced breakdown spectroscopy (LIBS) or spark emission spectroscopy (SES). The spark-induced microplasma was characterized by measuring the excitation temperature (15,000 - 35,000 K), electron density (1. Read More

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Real-time measurement of size-resolved elemental composition ratio for flame synthesized composite nanoparticle aggregates using a tandem SMPS-ICP-OES.

Aerosol Sci Technol 2017;51(3):311-316. Epub 2016 Dec 16.

Aerosol and Air Quality Research Laboratory, Washington University in St. Louis, St. Louis, Missouri, USA.

Composite nanoparticles find application in catalysis, drug delivery, and energy storage and require increasingly fine control of their physical properties and composition. While composite nanoparticles have been widely synthesized and characterized, little work has systematically correlated the initial concentration of precursors and the final composition of flame synthesized composite nanoparticles. This relationship is explored in a diffusion flame aerosol reactor by coupling a scanning mobility particle sizer (SMPS) with an inductively coupled plasma optical emission spectrometer (ICP-OES). Read More

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December 2016

Revisiting the size selective performance of EPA's high-volume total suspended particulate matter (Hi-Vol TSP) sampler.

Aerosol Sci Technol 2017 Apr;51(7):868-878

US EPA, Research Triangle Park, North Carolina, USA.

Under the National Ambient Air Quality Standard (NAAQS) for airborne lead, measurements are conducted by means of a high-volume total suspended particulate matter (Hi-Vol TSP) sampler. In the decade between 1973 and 1983, there were 12 publications that explored the sampling characteristics and effectiveness of the Hi-Vol TSP, yet there persists uncertainty regarding its performance. This article presents an overview of the existing literature on the performance of the Hi-Vol TSP, and identifies the reported sampler effectiveness with respect to four factors: particle size (reported effectiveness of 7%-100%), wind speed (-36% to 100%), sampler orientation (7%-100%), and operational state (107%-140%). Read More

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Clouds and "throat hit": Effects of liquid composition on nicotine emissions and physical characteristics of electronic cigarette aerosols.

Aerosol Sci Technol 2017 30;51(11):1231-1239. Epub 2017 Jun 30.

Aerosol Research Laboratory, Department of Mechanical Engineering, American University of Beirut, Beirut, Lebanon.

Electronic cigarettes (ECIGs) heat and vaporize a liquid mixture to produce an inhalable aerosol that can deliver nicotine to the user. The liquid mixture is typically composed of propylene glycol (PG) and vegetable glycerin (VG), in which are dissolved trace quantities of flavorants and, usually, nicotine. Due to their different chemical and thermodynamic properties, the proportions of PG and VG in the liquid solution may affect nicotine delivery and user sensory experience. Read More

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