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https://www.readbyqxmd.com/read/28098262/quantification-of-the-sources-and-composition-of-particulate-matter-by-field-deployable-mass-spectrometry-implications-for-air-quality-and-public-health
#1
Patrick L Hayes
Airborne particulate matter less than 2.5 μm in diameter (PM2.5) negatively impacts air quality in cities throughout the world where it has been linked to increased cardiac and respiratory morbidity and mortality. For this reason PM2.5 standards have been established by many countries and the World Health Organization. However, these guidelines are regularly exceeded in North America, Europe and East Asia. While PM2.5 is often reported as a single atmospheric species, it is actually a mixture of organic and inorganic compounds...
January 18, 2017: Analyst
https://www.readbyqxmd.com/read/28096368/elemental-sulfur-aerosol-forming-mechanism
#2
Manoj Kumar, Joseph S Francisco
Elemental sulfur aerosols are ubiquitous in the atmospheres of Venus, ancient Earth, and Mars. There is now an evolving body of evidence suggesting that these aerosols have also played a role in the evolution of early life on Earth. However, the exact details of their formation mechanism remain an open question. The present theoretical calculations suggest a chemical mechanism that takes advantage of the interaction between sulfur oxides, SOn (n = 1, 2, 3) and hydrogen sulfide (nH2S), resulting in the efficient formation of a Sn+1 particle...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28095671/use-of-calculated-physicochemical-properties-to-enhance-quantitative-response-when-using-charged-aerosol-detection
#3
Max W Robinson, Alan P Hill, Simon A Readshaw, John C Hollerton, Richard J Upton, Sean M Lynn, Steve C Besley, Bob J Boughtflower
Universal quantitative detection without the need for analyte reference standards would offer substantial benefits in many areas of analytical science. The quantitative capability of high-performance liquid chromatography (HPLC) with charged aerosol detection (CAD) was investigated for 50 compounds with a wide range of physical and chemical properties. It is widely believed that CAD is a mass detector. Quantification of the 50 compounds using a generic calibrant and mass calibration achieved an average error of 11...
January 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28088024/multi-year-record-of-atmospheric-and-snow-surface-nitrate-in-the-central-antarctic-plateau
#4
R Traversi, S Becagli, M Brogioni, L Caiazzo, V Ciardini, F Giardi, M Legrand, G Macelloni, B Petkov, S Preunkert, C Scarchilli, M Severi, V Vitale, R Udisti
Continuous all year-round samplings of atmospheric aerosol and surface snow at high (daily to 4-day) resolution were carried out at Dome C since 2004-05 to 2013 and nitrate records are here presented. Basing on a larger statistical data set than previous studies, results confirm that nitrate seasonal pattern is characterized by maxima during austral summer for both aerosol and surface snow, occurring in-phase with solar UV irradiance. This temporal pattern is likely due to a combination of nitrate sources and post-depositional processes whose intensity usually enhances during the summer...
December 30, 2016: Chemosphere
https://www.readbyqxmd.com/read/28088005/nicotine-hydrogen-tartrate-loaded-chitosan-nanoparticles-formulation-characterization-and-in-vitro-delivery-from-dry-powder-inhaler-formulation
#5
Hui Wang, Graeme George, Selena Bartlett, Changyou Gao, Nazrul Islam
This study reports the development of nanoparticles in the form of inhalable micro-aggregates of biodegradable chitosan (CS) loaded with nicotine hydrogen tartrate (NHT) for potential pulmonary delivery of nicotine from dry powder inhaler (DPI) formulations with prolonged release profile. The NHT-loaded CS particles were prepared using a water-in-oil emulsion crosslinking method. The prepared particles were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for morphological studies; Zetasizer and Mastersizer were applied for particle size analysis...
January 11, 2017: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/28079222/infrared-characterisation-of-acetonitrile-and-propionitrile-aerosols-under-titan-s-atmospheric-conditions
#6
C Ennis, R Auchettl, M Ruzi, E G Robertson
Pure, crystalline acetonitrile (CH3CN) and propionitrile (CH3CH2CN) particles were formed in a collisional cooling cell allowing for infrared (IR) signatures to be compiled from 50 to 5000 cm(-1). The cell temperature and pressure conditions were controlled to simulate Titan's lower atmosphere (80-130 K and 1-100 mbar), allowing for the comparison of laboratory data to the spectra obtained from the Cassini-Huygens mission. The far-IR features confirmed the morphology of CH3CN aerosols as the metastable β-phase (monoclinic) ice, however, a specific crystalline phase for CH3CH2CN could not be verified...
January 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28078345/comparison-between-the-optical-properties-of-aerosols-in-the-fine-and-coarse-fractions-over-valladolid-spain
#7
S Mogo, J F López, V E Cachorro, A de Frutos, R Zocca, A Barroso, D Mateos, E Conceição
Continuous measurements of the optical properties of aerosol particles have been made at Valladolid, Spain, covering the period from June 2011 to July 2012. The measurements were made at two size cuts: sub-10 μm and sub-1 μm (PM10 and PM1). The data measured were the scattering and backscattering coefficients, σs and σbs, obtained from an integrating nephelometer, and the absorption coefficient, σa, obtained from a particle soot absorption photometer. Spectrally resolved data were obtained from both instruments at 3 wavelengths (blue/green/red) at low relative humidity (RH < 40%)...
January 12, 2017: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/28072853/terrestrial-macrofungal-diversity-from-the-tropical-dry-evergreen-biome-of-southern-india-and-its-potential-role-in-aerobiology
#8
Hema Priyamvada, M Akila, Raj Kamal Singh, R Ravikrishna, R S Verma, Ligy Philip, R R Marathe, L K Sahu, K P Sudheer, S S Gunthe
Macrofungi have long been investigated for various scientific purposes including their food and medicinal characteristics. Their role in aerobiology as a fraction of the primary biological aerosol particles (PBAPs), however, has been poorly studied. In this study, we present a source of macrofungi with two different but interdependent objectives: (i) to characterize the macrofungi from a tropical dry evergreen biome in southern India using advanced molecular techniques to enrich the database from this region, and (ii) to assess whether identified species of macrofungi are a potential source of atmospheric PBAPs...
2017: PloS One
https://www.readbyqxmd.com/read/28071047/linking-load-fuel-and-emission-controls-to-photochemical-production-of-secondary-organic-aerosol-from-a-diesel-engine
#9
Shantanu H Jathar, Beth Friedman, Abril A Galang, Michael F Link, Patrick Brophy, John Volckens, Sailaja Eluri, Delphine K Farmer
Diesel engines are important sources of fine particle pollution in urban environments but their contribution to the atmospheric formation of secondary organic aerosol (SOA) is not well constrained. We investigated direct emissions of primary organic aerosol (POA) and photochemical production of SOA from a diesel engine using an oxidation flow reactor (OFR). In less than a day of simulated atmospheric aging, SOA production exceeded POA emissions by an order of magnitude or more. Efficient combustion at higher engine loads coupled to the removal of SOA precursors and particle emissions by aftertreatment systems reduced POA emission factors by an order of magnitude and SOA production factors by factors of 2-10...
January 10, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28070849/investigation-into-the-manufacture-and-properties-of-inhalable-high-dose-dry-powders-produced-by-comilling-api-and-lactose-with-magnesium-stearate
#10
Michael Lau, Paul M Young, Daniela Traini
The aim of the study was to understand the impact of different concentrations of the additive material, magnesium stearate (MGST), and the active pharmaceutical ingredient (API), respectively, on the physicochemical properties and aerosol performance of comilled formulations for high-dose delivery. Initially, blends of API/lactose with different concentrations of MGST (1-7.5% w/w) were prepared and comilled by the jet-mill apparatus. The optimal concentration of MGST in comilled formulations was investigated, specifically for agglomerate structure and strength, particle size, uniformity of content, surface coverage, and aerosol performance...
January 9, 2017: AAPS PharmSciTech
https://www.readbyqxmd.com/read/28070713/porous-mannitol-carrier-for-pulmonary-delivery-of-cyclosporine-a-nanoparticles
#11
Sharon Shui Yee Leung, Jennifer Wong, Heloisa Victorino Guerra, Kevin Samnick, Robert K Prud'homme, Hak-Kim Chan
This study employed the ultrasonic spray-freeze-drying technique to prepare porous mannitol carriers that incorporated hydrophobic cyclosporine A (CsA) nanoparticles (NPs) for pulmonary delivery. Two nanosuspension stabilization systems, (1) a combination of lecithin and lactose system and (2) a D-α-tocopheryl polyethylene glycol succinate (TPGS) system, were investigated. The ability of the lecithin and TPGS in anchoring the hydrophobic CsA NPs to the porous hydrophilic mannitol structure was first reported...
January 9, 2017: AAPS Journal
https://www.readbyqxmd.com/read/28066694/ice-residual-properties-in-mixed-phase-clouds-at-the-high-alpine-jungfraujoch-site
#12
Piotr Kupiszewski, Marco Zanatta, Stephan Mertes, Paul Vochezer, Gary Lloyd, Johannes Schneider, Ludwig Schenk, Martin Schnaiter, Urs Baltensperger, Ernest Weingartner, Martin Gysel
Ice residual (IR) and total aerosol properties were measured in mixed-phase clouds (MPCs) at the high-alpine Jungfraujoch research station. Black carbon (BC) content and coating thickness of BC-containing particles were determined using single-particle soot photometers. The ice activated fraction (IAF), derived from a comparison of IR and total aerosol particle size distributions, showed an enrichment of large particles in the IR, with an increase in the IAF from values on the order of 10(-4) to 10(-3) for 100 nm (diameter) particles to 0...
October 27, 2016: Journal of Geophysical Research. Atmospheres: JGR
https://www.readbyqxmd.com/read/28066027/light-source-effects-on-aerosol-photoacoustic-spectroscopy-measurements
#13
James G Radney, Christopher D Zangmeister
Photoacoustic spectroscopy measurements of flame-generated soot aerosol coated with small amounts of water yielded absorption enhancements that were dependent on the laser used: quasi-continuous wave (Q-CW, ≈ 650 ps pulse duration and 78 MHz repetition rate) versus continuous wave (CW). Water coating thickness was controlled by exposing the aerosol to a set relative humidity (RH). At ≈ 85 % RH, the mass of the soot particles increased by an amount comparable to a monolayer of water being deposited and enhanced the measured absorption by 36 % and 15 % for the Q-CW and CW lasers, respectively...
January 2017: Journal of Quantitative Spectroscopy & Radiative Transfer
https://www.readbyqxmd.com/read/28063711/fine-particulates-over-south-asia-review-and-meta-analysis-of-pm2-5-source-apportionment-through-receptor-model
#14
Nandita Singh, Vishnu Murari, Manish Kumar, S C Barman, Tirthankar Banerjee
Fine particulates (PM2.5) constitute dominant proportion of airborne particulates and have been often associated with human health disorders, changes in regional climate, hydrological cycle and more recently to food security. Intrinsic properties of particulates are direct function of sources. This initiates the necessity of conducting a comprehensive review on PM2.5 sources over South Asia which in turn may be valuable to develop strategies for emission control. Particulate source apportionment (SA) through receptor models is one of the existing tool to quantify contribution of particulate sources...
January 4, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28062701/widespread-virus-replication-in-alveoli-drives-acute-respiratory-distress-syndrome-in-aerosolized-h5n1-influenza-infection-of-macaques
#15
Elizabeth R Wonderlich, Zachary D Swan, Stephanie J Bissel, Amy L Hartman, Jonathan P Carney, Katherine J O'Malley, Adebimpe O Obadan, Jefferson Santos, Reagan Walker, Timothy J Sturgeon, Lonnie J Frye, Pauline Maiello, Charles A Scanga, Jennifer D Bowling, Anthea L Bouwer, Parichat A Duangkhae, Clayton A Wiley, JoAnne L Flynn, Jieru Wang, Kelly S Cole, Daniel R Perez, Douglas S Reed, Simon M Barratt-Boyes
Human infections with highly pathogenic avian influenza A (H5N1) virus are frequently fatal but the mechanisms of disease remain ill-defined. H5N1 infection is associated with intense production of proinflammatory cytokines, but whether this cytokine storm is the main cause of fatality or is a consequence of extensive virus replication that itself drives disease remains controversial. Conventional intratracheal inoculation of a liquid suspension of H5N1 influenza virus in nonhuman primates likely results in efficient clearance of virus within the upper respiratory tract and rarely produces severe disease...
January 6, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28062365/assessment-of-new-generation-high-power-electronic-nicotine-delivery-system-as-thermal-aerosol-generation-device-for-inhaled-bronchodilators
#16
Jérémie Pourchez, Fabien de Oliveira, Sophie Perinel-Ragey, Thierry Basset, Jean-Michel Vergnon, Nathalie Prévôt
PURPOSE: A need remains for alternative devices for aerosol drug delivery that are low cost, convenient and easy to use for the patient, but also capable of producing small-sized aerosol particles. This study investigated the potential of recent high power electronic nicotine delivery systems (ENDS) as aerosol generation devices for inhaled bronchodilators. METHODS: The particle size distribution was measured using a cascade impactor. The delivery of terbutaline sulfate, a current bronchodilator used for asthma or COPD therapy by inhalation, was studied...
January 4, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28060511/cluster-model-studies-of-anion-and-molecular-specificities-via-electrospray-ionization-photoelectron-spectroscopy
#17
Xue-Bin Wang
Ion specificity, a widely observed macroscopic phenomenon in condensed phases and at interfaces, is a fundamental chemical physics issue. Herein we report our recent studies of such effects using cluster models in an "atom-by-atom" and "molecule-by-molecule" fashion not possible with the condensed-phase methods. We use electrospray ionization (ESI) to generate molecular and ionic clusters to simulate key molecular entities involved in local binding regions, and characterize them employing negative ion photoelectron spectroscopy (NIPES)...
January 6, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28059358/aerosol-optical-depth-under-clear-sky-conditions-derived-from-sea-surface-reflection-of-lidar-signals
#18
Min He, Yongxiang Hu, Jian Ping Huang, Knut Stamnes
There are considerable demands for accurate atmospheric correction of satellite observations of the sea surface or subsurface signal. Surface and sub-surface reflection under "clear" atmospheric conditions can be used to study atmospheric correction for the simplest possible situation. Here "clear" sky means a cloud-free atmosphere with sufficiently small aerosol particles. The "clear" aerosol concept is defined according to the spectral dependence of the scattering cross section on particle size. A 5-year combined CALIPSO and AMSR-E data set was used to derive the aerosol optical depth (AOD) from the lidar signal reflected from the sea surface...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28059151/influence-of-metal-mediated-aerosol-phase-oxidation-on-secondary-organic-aerosol-formation-from-the-ozonolysis-and-oh-oxidation-of-%C3%AE-pinene
#19
Biwu Chu, John Liggio, Yongchun Liu, Hong He, Hideto Takekawa, Shao-Meng Li, Jiming Hao
The organic component is the most abundant fraction of atmospheric submicron particles, while the formation mechanisms of secondary organic aerosol (SOA) are not fully understood. The effects of sulfate seed aerosols on SOA formation were investigated with a series of experiments carried out using a 9 m(3) smog chamber. The presence of FeSO4 or Fe2(SO4)3 seed aerosols decreased SOA yields and increased oxidation levels in both ozonolysis and OH-oxidation of α-pinene compared to that in the presence of ZnSO4 or (NH4)2SO4...
January 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28056077/heterogeneous-ice-nucleation-by-soufriere-hills-volcanic-ash-immersed-in-water-droplets
#20
T P Mangan, J D Atkinson, J W Neuberg, D O'Sullivan, T W Wilson, T F Whale, L Neve, N S Umo, T L Malkin, B J Murray
Fine particles of ash emitted during volcanic eruptions may sporadically influence cloud properties on a regional or global scale as well as influencing the dynamics of volcanic clouds and the subsequent dispersion of volcanic aerosol and gases. It has been shown that volcanic ash can trigger ice nucleation, but ash from relatively few volcanoes has been studied for its ice nucleating ability. In this study we quantify the efficiency with which ash from the Soufriere Hills volcano on Montserrat nucleates ice when immersed in supercooled water droplets...
2017: PloS One
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