Science.gov

Sample records for atmospheric material particles

  1. Magnetic properties of atmospheric particles

    NASA Astrophysics Data System (ADS)

    McIntosh, G.; Aranzaru Revuelta, M.; Pey, J.; Noriega Salmon, R.; Artinano Rodriguez de Torres, B.; Querol, X.; Alastuey, A.

    2012-04-01

    The magnetic and chemical properties of a series of size-fractioned atmospheric particle filter samples (PM10, PM2.5 and PM1) from Barcelona have been studied. These results have been compared with those obtained from dust and particle samples taken from potential geogenic and anthropogenic particle sources (North African dust, Spanish top soils and vehicle-derived particles) and from biomagnetic monitoring (tree leaves, needles and bark). The filter samples are dominated by magnetically soft properties. The ratio of anhysteretic to isothermal remanence increases and the isothermal remanence coercivity decreases, with decreasing size fraction. This is interpreted in terms of smaller average magnetic grain sizes and increased relative importance of superparamagnetic grains. Concentration-dependent magnetic parameters most closely correlate with the concentration of antimony, a tracer element commonly related to vehicle brake dust. The correlation decreases with decreasing size fraction, suggesting it is associated with larger magnetic grains. The dust and vehicle-derived particles can be distinguished on the basis of different combinations of magnetic parameters. Applying these results to the filter samples supports the idea that brake wear particles make an important contribution to the magnetic signal of atmospheric particles, at least in urban settings. It can also be seen that the results obtained from biomagnetic monitoring closely mimic those obtained from filter samples, suggesting a similar control and highlighting their suitability for study in this field.

  2. The atmosphere as particle detector

    NASA Technical Reports Server (NTRS)

    Stanev, Todor

    1990-01-01

    The possibility of using an inflatable, gas-filled balloon as a TeV gamma-ray detector on the moon is considered. By taking an atmosphere of Xenon gas there, or by extracting it on the moon, a layman's detector design is presented. In spite of its shortcomings, the exercise illustrates several of the novel features offered by particle physics on the moon.

  3. Atmospheric discharges and particle fluxes

    NASA Astrophysics Data System (ADS)

    Chilingarian, A.; Chilingaryan, S.; Reymers, A.

    2015-07-01

    Fluxes of the electrons, gamma rays, and neutrons observed by particle detectors located on the Earth's surface during thunderstorms originate so-called Thunderstorm Ground Enhancements (TGEs). The relativistic runaway electron avalanches giving rise to TGEs originate in the thundercloud's lower dipole between the main negatively charged region in the middle of the thundercloud and transient lower positively charged region. Acceleration of electrons in the upper dipole between main negative and main positive charge regions leads to initiation of the terrestrial gamma flashes (TGFs) intensive researched during the last two decades by orbiting gamma ray observatories. TGFs are exceptionally intense, submillisecond bursts of electromagnetic radiation directed to the open space from the thunderstorm atmosphere. Unlike visible lightning, TGF beams do not create a hot plasma channel and optical flash; hence, in the literature they got name "dark lightning." We investigate the TGEs development in 1 min and 1 s time series of particle detector count rates. Synchronized time series of the near-surface electric field and lightning occurrences allows interconnecting two atmospheric phenomena. Registration of the Extensive Air Showers allows approaching problems of relation of the lightning occurrences and particle fluxes.

  4. Energetic Particle Influence on the Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Mironova, Irina A.; Aplin, Karen L.; Arnold, Frank; Bazilevskaya, Galina A.; Harrison, R. Giles; Krivolutsky, Alexei A.; Nicoll, Keri A.; Rozanov, Eugene V.; Turunen, Esa; Usoskin, Ilya G.

    2015-11-01

    This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth's atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere.

  5. Vapor scavenging by atmospheric aerosol particles

    SciTech Connect

    Andrews, E.

    1996-05-01

    Particle growth due to vapor scavenging was studied using both experimental and computational techniques. Vapor scavenging by particles is an important physical process in the atmosphere because it can result in changes to particle properties (e.g., size, shape, composition, and activity) and, thus, influence atmospheric phenomena in which particles play a role, such as cloud formation and long range transport. The influence of organic vapor on the evolution of a particle mass size distribution was investigated using a modified version of MAEROS (a multicomponent aerosol dynamics code). The modeling study attempted to identify the sources of organic aerosol observed by Novakov and Penner (1993) in a field study in Puerto Rico. Experimentally, vapor scavenging and particle growth were investigated using two techniques. The influence of the presence of organic vapor on the particle`s hydroscopicity was investigated using an electrodynamic balance. The charge on a particle was investigated theoretically and experimentally. A prototype apparatus--the refractive index thermal diffusion chamber (RITDC)--was developed to study multiple particles in the same environment at the same time.

  6. Degradation of materials in the atmosphere

    SciTech Connect

    Graedel, T.E.; R. McGill

    1986-11-01

    This paper provides a perspective on the potential for materials degradation as a consequence of atmospheric exposure. Ferrous metals, masonry, zinc, copper, and perhaps some paints appear most likely to be degraded. The regimes of greatest concern vary with different materials, but they include dew, fog, airborne particles, and indoor air. The results, however, rest on a rather sparse data base and take no account of synergistic deterioration effects of corrodents; thus, the presentation should be considered a starting point for discussion and experimentation.

  7. Alternative pathway for atmospheric particles growth

    PubMed Central

    Monge, Maria Eugenia; Rosenørn, Thomas; Favez, Olivier; Müller, Markus; Adler, Gabriela; Abo Riziq, Ali; Rudich, Yinon; Herrmann, Hartmut; George, Christian; D’Anna, Barbara

    2012-01-01

    Credible climate change predictions require reliable fundamental scientific knowledge of the underlying processes. Despite extensive observational data accumulated to date, atmospheric aerosols still pose key uncertainties in the understanding of Earth’s radiative balance due to direct interaction with radiation and because they modify clouds’ properties. Specifically, major gaps exist in the understanding of the physicochemical pathways that lead to aerosol growth in the atmosphere and to changes in their properties while in the atmosphere. Traditionally, the driving forces for particle growth are attributed to condensation of low vapor pressure species following atmospheric oxidation of volatile compounds by gaseous oxidants. The current study presents experimental evidence of an unaccounted-for new photoinduced pathway for particle growth. We show that heterogeneous reactions activated by light can lead to fast uptake of noncondensable Volatile Organic Compounds (VOCs) at the surface of particles when only traces of a photosensitizer are present in the seed aerosol. Under such conditions, size and mass increase; changes in the chemical composition of the aerosol are also observed upon exposure to volatile organic compounds such as terpenes and near-UV irradiation. Experimentally determined growth rate values match field observations, suggesting that this photochemical process can provide a new, unaccounted-for pathway for atmospheric particle growth and should be considered by models. PMID:22517749

  8. Particle Size Distributions in Atmospheric Clouds

    NASA Technical Reports Server (NTRS)

    Paoli, Roberto; Shariff, Karim

    2003-01-01

    In this note, we derive a transport equation for a spatially integrated distribution function of particles size that is suitable for sparse particle systems, such as in atmospheric clouds. This is done by integrating a Boltzmann equation for a (local) distribution function over an arbitrary but finite volume. A methodology for evolving the moments of the integrated distribution is presented. These moments can be either tracked for a finite number of discrete populations ('clusters') or treated as continuum variables.

  9. Nucleation and Growth of Atmospheric Particles

    SciTech Connect

    McMurry, P.; Kuang, C.; Barsanti, K.; Eisele, F.; Friedli, H.; Scheckman, J.; Titcombe, M.; Williams, B.; Zhao, J.; Smith, J.

    2010-03-15

    New particle formation (NPF) in the atmospheric is a two-step process: Nucleation leads to the birth of stable nuclei that subsequently grow to sizes that can be detected and affect the atmospheres radiative properties. Our group is studying both of these processes. Our nucleation research is largely supported by NSF and involves measurements of neutral molecular clusters formed by nucleation with a new custom-designed mass spectrometer (the Cluster-CIMS) and measurements of nanoparticle size distributions as small as 1 nm with a new aerosol spectrometer (the DEG SMPS). These measurements are providing new insights into aspects of cluster behavior that affect nucleation rates. The U.S. DOE supports our research on nanoparticle growth rates. This research couples physical and chemical measurements of aerosol properties and behavior. The TDCIMS, which enables real-time measurements of composition for freshly nucleated particles as small as 8 nm and was developed with support from DOE, is the most important tool in this work. Our most important discoveries about processes that affect growth rates are summarized in a recent PNAS article (doi:10.1073/pnas.0912127107). In short, this work has shown that alkylammonium-carboxylate salts, formed, for example, by reactions between amines and carboxylic acids, account for 2050% of the mass of freshly nucleated particles in locations that include Atlanta, Mexico City, Boulder, and Hyytil, while sulfates account for only about 10%. These newly discovered compounds help to explain the high growth rates of freshly nucleated particles that have been observed around the globe and help to explain why nucleation is an important atmospheric process, not just a scientific curiosity. Our poster will provide an overview of this work.

  10. A marine biogenic source of atmospheric ice-nucleating particles.

    PubMed

    Wilson, Theodore W; Ladino, Luis A; Alpert, Peter A; Breckels, Mark N; Brooks, Ian M; Browse, Jo; Burrows, Susannah M; Carslaw, Kenneth S; Huffman, J Alex; Judd, Christopher; Kilthau, Wendy P; Mason, Ryan H; McFiggans, Gordon; Miller, Lisa A; Nájera, Juan J; Polishchuk, Elena; Rae, Stuart; Schiller, Corinne L; Si, Meng; Temprado, Jesús Vergara; Whale, Thomas F; Wong, Jenny P S; Wurl, Oliver; Yakobi-Hancock, Jacqueline D; Abbatt, Jonathan P D; Aller, Josephine Y; Bertram, Allan K; Knopf, Daniel A; Murray, Benjamin J

    2015-09-10

    The amount of ice present in clouds can affect cloud lifetime, precipitation and radiative properties. The formation of ice in clouds is facilitated by the presence of airborne ice-nucleating particles. Sea spray is one of the major global sources of atmospheric particles, but it is unclear to what extent these particles are capable of nucleating ice. Sea-spray aerosol contains large amounts of organic material that is ejected into the atmosphere during bubble bursting at the organically enriched sea-air interface or sea surface microlayer. Here we show that organic material in the sea surface microlayer nucleates ice under conditions relevant for mixed-phase cloud and high-altitude ice cloud formation. The ice-nucleating material is probably biogenic and less than approximately 0.2 micrometres in size. We find that exudates separated from cells of the marine diatom Thalassiosira pseudonana nucleate ice, and propose that organic material associated with phytoplankton cell exudates is a likely candidate for the observed ice-nucleating ability of the microlayer samples. Global model simulations of marine organic aerosol, in combination with our measurements, suggest that marine organic material may be an important source of ice-nucleating particles in remote marine environments such as the Southern Ocean, North Pacific Ocean and North Atlantic Ocean. PMID:26354482

  11. Particle Suspension Mechanisms - Supplemental Material

    SciTech Connect

    Dillon, M B

    2011-03-03

    This supplemental material provides a brief introduction to particle suspension mechanisms that cause exfoliated skin cells to become and remain airborne. The material presented here provides additional context to the primary manuscript and serves as background for designing possible future studies to assess the impact of skin cells as a source of infectious aerosols. This introduction is not intended to be comprehensive and interested readers are encouraged to consult the references cited.

  12. Atmospheric Tar Balls: Particles from Biomass and Biofuel Burning

    NASA Technical Reports Server (NTRS)

    Posfai, Mihaly; Gelencser, Andras; Simonics, Renata; Arato, Krisztina; Li, Jia; Hobbs, Peter V.; Buseck, Peter R.

    2004-01-01

    Tar balls are amorphous, carbonaceous spherules that occur in the tropospheric aerosol as a result of biomass and biofuel burning. They form a distinct group of particles with diameters typically between 30 and 500 nm and readily identifiable with electron microscopy. Their lack of a turbostratic microstructure distinguishes them from soot, and their morphology and composition (approximately 90 mol% carbon) renders them distinct from other carbonaceous particles. Tar balls are particularly abundant in slightly aged (minutes to hours old) biomass smoke, indicating that they likely form by gas-to-particle conversion within smoke plumes. The material of tar balls is initially hygroscopic; however, the particles become largely insoluble as a result of free radical polymerization of their organic molecules. Consequently, tar balls are primarily externally mixed with other particle types, and they do not appreciably increase in size during aging. When tar balls coagulate with water-bearing particles, their material may partly dissolve and no longer be recognizable as distinct particles. Tar balls may contain organic compounds that absorb sunlight. They are an important, previously unrecognized type of carbonaceous (organic) atmospheric particle.

  13. Remarkable increase of organic particles in the atmosphere above Croatia

    NASA Astrophysics Data System (ADS)

    Furić, Krešimir; Ivanda, Mile; Kopic, Jasna Kučar; Mohaček, Vlasta

    1994-03-01

    The undesired man-influenced increase of organic material in the atmosphere above Croatia is observed and discussed. Two forms, one similar to natural cobweb, another described as cylinder shaped particles, were found in solid sediments of precipitates. The method of identifying these particles is emphasized, together with their physical and chemical properties. Using different methods a common core/coating structure is established. The structure and four distinct, obviously carefully selected diameters disclose the primary purpose of such a product. Other possible aims and consequences are also discussed.

  14. Phase of atmospheric secondary organic material affects its reactivity

    PubMed Central

    Kuwata, Mikinori; Martin, Scot T.

    2012-01-01

    The interconversion of atmospheric organic particles among solid, semisolid, and liquid phases is of keen current scientific interest, especially for particles of secondary organic material (SOM). Herein, the influence of phase on ammonia uptake and subsequent particle-phase reactions was investigated for aerosol particles of adipic acid and α-pinene ozonolysis SOM. The nitrogen content of the particles was monitored by online mass spectrometry for increasing ammonia exposure. Solid and semisolid adipic acid particles were inert to the ammonia uptake for low RH (< 5%). For the solid particles, ammonia exposure at high relative humidity (RH; > 94%) induced a first-order deliquescence phase transition into aqueous particles. Solid particles exposed to supersaturated (RH > 100%) conditions and cycled back to high RH (> 94%), thereby becoming acidic metastable particles, underwent a gradual second-order transition upon ammonia exposure to form aqueous, partially neutralized particles. For α-pinene SOM, ammonia exposure at low RH increased the particle-phase ammonium content by a small amount. Mass spectrometric observations suggest a mechanism of neutralization and co-condensation of acidic gas-phase species, consistent with a highly viscous semisolid upon which adsorption occurs. At high RH the ammonium content increased greatly, indicative of rapid diffusion and absorption in a liquid environment. The mass spectra indicated the production of organonitrogen compounds, possibly by particle-phase reactive chemistry. The present results demonstrate that phase can be a key regulator of the reactivity of atmospheric SOM particles. PMID:23045632

  15. Nanoporous Materials in Atmosphere Revitalization. Chapter 1

    NASA Technical Reports Server (NTRS)

    Hernandez-Maldonado, J.; Ishikawa, Yasuyuki; Luna, Bernadette; Junaedi, Christian; Mulloth, Lila; Perry, Jay L.; Raptis, Raphael G.; Roychoudhury, Subir

    2012-01-01

    Atmospheric Revitalization (AR) is the term the National Aeronautics and Space Administration (NASA) uses to encompass the engineered systems that maintain a safe, breathable gaseous atmosphere inside a habitable space cabin. An AR subsystem is a key part of the Environmental Control and Life Support (ECLS) system for habitable space cabins. The ultimate goal for AR subsystem designers is to 'close the loop', that is, to capture gaseous human metabolic products, specifically water vapor (H2O) and Carbon dioxide (CO2), for maximal Oxygen (o2) recovery and to make other useful resources from these products. The AR subsystem also removes trace chemical contaminants from the cabin atmosphere to preserve cabin atmospheric quality, provides O2 and may include instrumentation to monitor cabin atmospheric quality. Long duration crewed space exploration missions require advancements in AR process technologies in order to reduce power consumption and mass and to increase reliability compared to those used for shorter duration missions that are typically limited to Low Earth Orbit. For example, current AR subsystems include separate processors and process air flow loops for removing metabolic CO2 and volatile organic tract contaminants (TCs). Physical adsorbents contained in fixed, packed beds are employed in these processors. Still, isolated pockets of high carbon dioxide have been suggested as a trigger for crew headaches and concern persists about future cabin ammonia (NH3) levels as compared with historical flights. Developers are already focused on certain potential advancements. ECLS systems engineers envision improving the AR subsystem by combining the functions of TC control and CO2 removal into a single regenerable process and moving toward structured sorbents - monoliths - instead of granular material. Monoliths present a lower pressure drop and eliminate particle attrition problems that result from bed containment. New materials and configurations offer promise for lowering cabin levels of CO2 and NH3 as well as reducing power requirements and increasing reliability. This chapter summarizes the challenges faced by ECLS system engineers in pursuing these goals, and the promising materials developments that may be part of the technical solution for challenges of crewed space exploration beyond LEO.

  16. Atmospheric and environmental impacts of volcanic ash particle emissions

    NASA Astrophysics Data System (ADS)

    Durant, Adam

    2010-05-01

    Globally, at any one time, there may be 20 volcanoes erupting that collectively emit a constant flux of gases and aerosol, including silicate particles (tephra), to the atmosphere which influences processes including cloud microphysics, heterogeneous chemistry and radiative balance. The nature and impact of atmospheric volcanic particle fluxes depend on total mass erupted, emission rate, emission source location, physical and chemical properties of the particles, and the location and residence time of the particles in the atmosphere. Removal of ash particles from the atmosphere through sedimentation is strongly influenced by particle aggregation through hydrometeor formation, and convective instabilities such as mammatus. I will address the following questions: What are the atmospheric impacts of volcanic ash emissions? What controls the residence time of volcanic particles in the atmosphere? What affects particle accumulation at the surface? And what are the human and environmental impacts of ash fallout?

  17. A marine biogenic source of atmospheric ice-nucleating particles

    SciTech Connect

    Wilson, T. W.; Ladino, L. A.; Alpert, Peter A.; Breckels, M. N.; Brooks, I. M.; Browse, J.; Burrows, Susannah M.; Carslaw, K. S.; Huffman, J. A.; Judd, C.; Kilthau, W. P.; Mason, R. H.; McFiggans, Gordon; Miller, L. A.; Najera, J.; Polishchuk, E. A.; Rae, S.; Schiller, C. L.; Si, M.; Vergara Temprado, J.; Whale, Thomas; Wong, J P S; Wurl, O.; Yakobi-Hancock, J. D.; Abbatt, JPD; Aller, Josephine Y.; Bertram, Allan K.; Knopf, Daniel A.; Murray, Benjamin J.

    2015-09-09

    The formation of ice in clouds is facilitated by the presence of airborne ice nucleating particles1,2. Sea spray is one of the major global sources of atmospheric particles, but it is unclear to what extent these particles are capable of nucleating ice3–11. Here we show that material in the sea surface microlayer, which is enriched in surface active organic material representative of that found in sub-micron sea- spray aerosol12–21, nucleates ice under conditions that occur in mixed-phase clouds and high-altitude ice clouds. The ice active material is likely biogenic and is less than ~0.2 ?m in size. We also show that organic material (exudate) released by a common marine diatom nucleates ice when separated from cells and propose that organic material associated with phytoplankton cell exudates are a candidate for the observed ice nucleating ability of the microlayer samples. By combining our measurements with global model simulations of marine organic aerosol, we show that ice nucleating particles of marine origin are dominant in remote marine environments, such as the Southern Ocean, the North Pacific and the North Atlantic.

  18. Chemistry and Composition of Atmospheric Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Kolb, Charles E.; Worsnop, Douglas R.

    2012-05-01

    For more than two decades a cadre of physical chemists has focused on understanding the formation processes, chemical composition, and chemical kinetics of atmospheric aerosol particles and droplets with diameters ranging from a few nanometers to ˜10,000 nm. They have adapted or invented a range of fundamental experimental and theoretical tools to investigate the thermochemistry, mass transport, and chemical kinetics of processes occurring at nanoscale gas-liquid and gas-solid interfaces for a wide range of nonideal, real-world substances. State-of-the-art laboratory methods devised to study molecular spectroscopy, chemical kinetics, and molecular dynamics also have been incorporated into field measurement instruments that are deployed routinely on research aircraft, ships, and mobile laboratories as well as at field sites from megacities to the most remote jungle, desert, and polar locations. These instruments can now provide real-time, size-resolved aerosol particle physical property and chemical composition data anywhere in Earth's troposphere and lower stratosphere.

  19. Organic aggregate formation in aerosols and its impact on the physicochemical properties of atmospheric particles

    NASA Astrophysics Data System (ADS)

    Tabazadeh, Azadeh

    Fatty acid salts and "humic" materials, found in abundance in atmospheric particles, are both anionic surfactants. Such materials are known to form organic aggregates or colloids in solution at very low aqueous concentrations. In a marine aerosol, micelle aggregates can form at a low fatty acid salt molality of ˜10 -3 m. In other types of atmospheric particles, such as biomass burning, biogenic, soil dust, and urban aerosols, "humic-like" materials exist in sufficient quantities to form micelle-like aggregates in solution. I show micelle formation limits the ability of surface-active organics in aerosols to reduce the surface tension of an atmospheric particle beyond about 10 dyne cm -1. A general phase diagram is presented for anionic surfactants to explain how surface-active organics can change the water uptake properties of atmospheric aerosols. Briefly such molecules can enhance and reduce water uptake by atmospheric aerosols at dry and humid conditions, respectively. This finding is consistent with a number of unexplained field and laboratory observations. Dry electron microscope images of atmospheric particles often indicate that organics may coat the surface of particles in the atmosphere. The surfactant phase diagram is used to trace the particle path back to ambient conditions in order to determine whether such coatings can exist on wet ambient aerosols. Finally, I qualitatively highlight how organic aggregate formation in aerosols may change the optical properties and chemical reactivity of atmospheric particles.

  20. Catching Comet's Particles in the Earth's Atmosphere by Using Balloons

    NASA Astrophysics Data System (ADS)

    Potashko, Oleksandr; Viso, Michel

    The project is intended to catch cometary particles in the atmosphere by using balloons. The investigation is based upon knowledge that the Earth crosses the comet’s tails during the year. One can catch these particles at different altitudes in the atmosphere. So, we will be able to gradually advance in the ability to launch balloons from low to high altitudes and try to catch particles from different comet tails. The maximum altitude that we have to reach is 40 km. Both methods - distance observation and cometary samples from mission Stardust testify to the presence of organic components in comet’s particles. It would be useful to know more details about this organic matter for astrobiology; besides, the factor poses danger to the Earth. Moreover, it is important to prove that it is possible to get fundamental scientific results at low cost. In the last 5 years launching balloons has become popular and this movement looks like hackers’ one - as most of them occur without launch permission to airspace. The popularity of ballooning is connected with low cost of balloon, GPS unit, video recording unit. If you use iPhone, you have a light solution with GPS, video, picture and control function in one unit. The price of balloon itself begins from $50; it depends on maximum altitude, payload weight and material. Many university teams realized balloon launching and reached even stratosphere at an altitude of 33 km. But most of them take only video and picture. Meanwhile, it is possible to carry out scientific experiments by ballooning, for example to collect comet particles. There is rich experience at the moment of the use of mineral, chemical and isotopic analysis techniques and data of the comet’s dust after successful landing of StarDust capsule with samples in 2006. Besides, we may use absolutely perfect material to catch particles in the atmosphere, which was used by cosmic missions such as Stardust and Japanese Hayabusa. As to balloon launches, we could use Indian Space Research Organization experience that launched a balloon to stratosphere in 2009 and successfully caught particles with organics at an altitude of 42 km. The main aim of the project is to catch cometary particles by using balloons and to make this method steady and reliable. Why are the comet particles interesting? The nature of a comet is full of puzzles; many researchers think that comets may give keys to the origin of the Solar System and origin of life on the Earth. 2014 and 2015 are special years for comet science: mission Rozetta will reach the vicinity of the comet 67P/Churyumov-Gerasimenko - 10 years after leaving the Earth. Using astronomic data, one may choose date for ballooning, specify the altitude of comet particles by photometry and laser measurement of particle outburst. After height measurement one may launch a balloon. For example, for Draconids particles (Parent comet: 21PGiacobini-Zinner) the expected time of outburst maximum - hence that for catching is 22:42 UT, October 6, 2014. The best conditions for catching will be in Greenland and extreme north-eastern part of North America. Draconids are very convenient for the initial stage of the project - the altitude of observed Draconids outburst is 10 km. One may catch them above 10 km, e.g. 10500 m. We consider ballooning is quite a good method to get experimental data as an additional technique in comparison with big space missions. Moreover, it might be a part of cosmic mission to other planets such as Mars and Venus. The approach of the project is to make targeting catch of comet particles. The method consists of choosing the right place and time for ballooning.

  1. Images reveal that atmospheric particles can undergo liquid-liquid phase separations

    SciTech Connect

    You, Yuan; Renbaum-Wolff, Lindsay; Carreras-Sospedra, Marc; Hanna, Sarah; Hiranuma, Naruki; Kamal, Saeid; Smith, Mackenzie L.; Zhang, Xiaolu; Weber, Rodney; Shilling, John E.; Dabdub, Donald; Martin, Scot T.; Bertram, Allan K.

    2012-07-30

    A large fraction of submicron atmospheric particles contains both organic material and inorganic salts. As the relative humidity cycles in the atmosphere, these mixed particles can undergo a range of phase transitions, possibly including liquid-liquid phase separation. If liquid-liquid phase separation occurs, the gas-particle partitioning of atmospheric semi-volatile organic compounds, the scattering and absorption of solar radiation, and the uptake of reactive gas species on atmospheric particles will be affected, with important implications for climate predictions. The actual occurrence of these types of phase transitions within individual atmospheric particles has been considered uncertain, in large part because of the absence of observations for real-world samples. Here, using optical and fluorescence microscopy, we observe the coexistence of two non-crystalline phases in particles generated from real-world samples collected on multiple days in Atlanta, Georgia, and in particles generated in the laboratory using atmospheric conditions. These results reveal that atmospheric particles can undergo liquid-liquid phase separations. Using a box model, we show that liquid-liquid phase separation can result in increased concentrations of gas-phase NO3 and N2O5 in the Atlanta region, due to decreased particle uptake of N2O5.

  2. Particle Dispersion in the Neutral Atmospheric Surface Layer

    NASA Astrophysics Data System (ADS)

    Belan, Sergey; Lebedev, Vladimir; Falkovich, Gregory

    2016-04-01

    We address theoretically the longstanding problem of particle dispersion in the lower atmosphere. The evolution of particle concentration under an absorbing boundary condition at the ground is described. We derive a close-form solution for the downwind surface density of deposited particles and find how the number of airborne particles decreases with time. The problem of the plume formation above the extended surface source is also solved analytically. At the end, we show how turbophoresis modifies the mean settling velocity of particles.

  3. Teaching Materials: Stellar Atmospheres/Radiative Transfer

    NASA Astrophysics Data System (ADS)

    Hawley, S. L.; Ayres, T. R.

    1996-05-01

    We will present a selection of modern teaching materials for courses in Stellar Atmospheres and Radiative Transfer that have been collected from a wide variety of sources. We will provide brief synopses of each book, or set of of notes, and endeavor to compare and contrast the different presentations of the material. One of the newer additions to the literature is ``Radiative Transfer in Stellar Atmospheres,'' lecture notes from R.J. Rutten based on courses taught at Utrecht University. In addition, I. Hubeny and D. Mihalas presently are writing a new edition of Mihalas' famous ``Stellar Atmospheres.'' Other books we are aware of range from the planning stages to near completion. We will emphasize the diversity of styles and presentation techniques, but will try to make clear the central themes around which any successful Stellar Atmospheres/Radiative Transfer course must be built.

  4. Images reveal that atmospheric particles can undergo liquid–liquid phase separations

    PubMed Central

    You, Yuan; Renbaum-Wolff, Lindsay; Carreras-Sospedra, Marc; Hanna, Sarah J.; Hiranuma, Naruki; Kamal, Saeid; Smith, Mackenzie L.; Zhang, Xiaolu; Weber, Rodney J.; Shilling, John E.; Dabdub, Donald; Martin, Scot T.; Bertram, Allan K.

    2012-01-01

    A large fraction of submicron atmospheric aerosol particles contains both organic material and inorganic salts. As the relative humidity cycles in the atmosphere and the water content of the particles correspondingly changes, these mixed particles can undergo a range of phase transitions, possibly including liquid–liquid phase separation. If liquid–liquid phase separation occurs, the gas-particle partitioning of atmospheric semivolatile organic compounds, the scattering and absorption of solar radiation, and the reactive uptake of gas species on atmospheric particles may be affected, with important implications for climate predictions. The actual occurrence of liquid–liquid phase separation within individual atmospheric particles has been considered uncertain, in large part because of the absence of observations for real-world samples. Here, using optical and fluorescence microscopy, we present images that show the coexistence of two noncrystalline phases for real-world samples collected on multiple days in Atlanta, GA as well as for laboratory-generated samples under simulated atmospheric conditions. These results reveal that atmospheric particles can undergo liquid–liquid phase separations. To explore the implications of these findings, we carried out simulations of the Atlanta urban environment and found that liquid–liquid phase separation can result in increased concentrations of gas-phase NO3 and N2O5 due to decreased particle uptake of N2O5. PMID:22847443

  5. Dielectric particle injector for material processing

    NASA Technical Reports Server (NTRS)

    Leung, Philip L. (Inventor)

    1992-01-01

    A device for use as an electrostatic particle or droplet injector is disclosed which is capable of injecting dielectric particles or droplets. The device operates by first charging the dielectric particles or droplets using ultraviolet light induced photoelectrons from a low work function material plate supporting the dielectric particles or droplets, and then ejecting the charged particles or droplets from the plate by utilizing an electrostatic force. The ejected particles or droplets are mostly negatively charged in the preferred embodiment; however, in an alternate embodiment, an ion source is used instead of ultraviolet light to eject positively charged dielectric particles or droplets.

  6. EDITORIAL: Focus on high energy particles and atmospheric processes

    NASA Astrophysics Data System (ADS)

    Harrison, R. Giles; Nicoll, Keri; Takahashi, Yukihiro; Yair, Yoav

    2015-10-01

    The letters published in the ‘Focus issue on high energy particles and atmospheric processes’ serve to broaden the discussion about the influence of high energy particles on the atmosphere beyond their possible effects on clouds and climate. These letters link climate and meteorological processes with atmospheric electricity, atmospheric chemistry, high energy physics and aerosol science from the smallest molecular cluster ions through to liquid droplets. Progress in such a disparate and complex topic is very likely to benefit from continued interdisciplinary interactions between traditionally distinct science areas.

  7. Wear of hard materials by hard particles

    SciTech Connect

    Hawk, Jeffrey A.

    2003-10-01

    Hard materials, such as WC-Co, boron carbide, titanium diboride and composite carbide made up of Mo2C and WC, have been tested in abrasion and erosion conditions. These hard materials showed negligible wear in abrasion against SiC particles and erosion using Al2O3 particles. The WC-Co materials have the highest wear rate of these hard materials and a very different material removal mechanism. Wear mechanisms for these materials were different for each material with the overall wear rate controlled by binder composition and content and material grain size.

  8. Atmospheric new particle formation as a source of CCN in the eastern Mediterranean marine boundary layer

    NASA Astrophysics Data System (ADS)

    Kalivitis, N.; Kerminen, V.-M.; Kouvarakis, G.; Stavroulas, I.; Bougiatioti, A.; Nenes, A.; Manninen, H. E.; Petäjä, T.; Kulmala, M.; Mihalopoulos, N.

    2015-08-01

    While cloud condensation nuclei (CCN) production associated with atmospheric new particle formation (NPF) is thought to be frequent throughout the continental boundary layers, few studies on this phenomenon in marine air exist. Here, based on simultaneous measurement of particle number size distributions, CCN properties and aerosol chemical composition, we present the first direct evidence on CCN production resulting from NPF in the eastern Mediterranean atmosphere. We show that condensation of both gaseous sulfuric acid and organic compounds from multiple sources leads to the rapid growth of nucleated particles to CCN sizes in this environment during the summertime. Sub-100 nm particles were found to be substantially less hygroscopic than larger particles during the period with active NPF and growth (the value of κ was lower by 0.2-0.4 for 60 nm particles compared with 120 nm particles), probably due to enrichment of organic material in the sub-100 nm size range. The aerosol hygroscopicity tended to be at minimum just before the noon and at maximum in the afternoon, which was very likely due to the higher sulfate-to-organic ratios and higher degree of oxidation of the organic material during the afternoon. Simultaneous with the formation of new particles during daytime, particles formed during the previous day or even earlier were growing into the size range relevant to cloud droplet activation, and the particles formed in the atmosphere were possibly mixed with long-range-transported particles.

  9. Can lipids form crystalline films on atmospheric particles?

    NASA Astrophysics Data System (ADS)

    Aumann, E.; Cabrera, J.; Tabazadeh, A.

    2006-12-01

    Many studies assume that fatty acids or lipids can readily form films on aqueous particles in the atmosphere since fatty acids are known to be very strong film forming agents. Specifically, stearic acid is often used in laboratory and modeling studies to mimic the composition of particle surfaces in the atmosphere. For most industrial and engineering purposes, lipid films are spread over aqueous surfaces by first dissolving the lipid in an organic solvent, such as hexane. When hexane evaporates from the lipid/hexane mixture, a crystalline lipid film is left behind on the aqueous surface. Lipids in atmospheric particles, like stearic acid, are primarily emitted as oil drops that form crystals when cooled. In the atmosphere, lipid crystalline particulate matter can coagulate with aqueous particles to produce mixed aerosols, containing lipids in aqueous solutions. We used laboratory measurements to determine the rate of stearic acid crystal spreading on water in the absence of on organic solvent. From these measurements, we show that the time required to spread a lipid crystal on an aqueous surface to produce a film is much longer than a typical 2-week lifetime of an atmospheric particle. Therefore, we suggest that lipids, capable of forming crystalline, impermeable films on particle surfaces, are most likely tied up in a crystalline phase during their lifecycle in the atmosphere.

  10. Designing Jammed Materials from the Particle Up

    NASA Astrophysics Data System (ADS)

    Miskin, Marc

    2015-03-01

    Identifying which microscopic features produce a desired macroscopic behavior is a problem at the forefront of materials science. This task is materials design, and within it, new challenges have emerged from tailoring packings of particles jammed into a rigid state. For these materials, particle shape is a key parameter by which the response of a packing can be tuned. Yet designing via shape faces two unique complications: first there is no general theory that calculates the response of an aggregate given a particle shape, and second, there is no straightforward way to explore the space of all particle geometries. This talk summarizes recent results that address these challenges to design jammed materials from the particle up. It shows how simulations, experiments, and state-of-the-art optimization engines come together to form a complete system that identifies extreme materials. As examples, it will show how this system can create particle shapes that form the stiffest, softest, densest, loosest, most dissipative and strain-stiffening aggregates. Finally, it will discuss the how these results relate to the general task of materials design and the exciting possibilities associated with optimizing, tuning and rationally constructing new breeds of jammed materials.

  11. Dispersion of aerosol particles in the atmosphere: Fukushima

    NASA Astrophysics Data System (ADS)

    Haszpra, Tímea; Lagzi, István; Tél, Tamás

    2013-04-01

    Investigation of dispersion and deposition of aerosol particles in the atmosphere is an essential issue, because they have an effect on the biosphere and atmosphere. Moreover, aerosol particles have different transport properties and chemical and physical transformations in the atmosphere compared to gas phase air pollutants. The motion of a particle is described by a set of ordinary differential equations. The large-scale dynamics in the horizontal direction can be described by the equations of passive scalar advection, but in the vertical direction a well-defined terminal velocity should be taken into account as a term added to the vertical wind component. In the planetary boundary layer turbulent diffusion has an important role in the particle dispersion, which is taken into account by adding stochastic terms to the deterministic equations above. Wet deposition is also an essential process in the lower levels of the atmosphere, however, its precise parameterization is a challenge. For the simulations the wind field and other necessary data were taken from the ECMWF ERA-Interim database. In the case of the Fukushima Daiichi nuclear disaster (March-April 2011) radioactive aerosol particles were also released in the planetary boundary layer. Simulations (included the continuous and varying emission from the nuclear power plant) will be presented for the period of 14-23 March. Results show that wet deposition also has to be taken into consideration in the lower levels of the atmosphere. Furthermore, dynamical system characteristics are evaluated for the aerosol particle dynamics. The escape rate of particles was estimated both with and without turbulent diffusion, and in both cases when there was no wet deposition and also when wet deposition was taken into consideration.

  12. Particle Rebound and Phase State of Secondary Organic Material

    NASA Astrophysics Data System (ADS)

    Bateman, A.; Bertram, A. K.; Martin, S. T.

    2014-12-01

    Secondary organic material (SOM) is produced in the atmosphere from the oxidation of volatile organic compounds emitted from anthropogenic and biogenic sources. Aerosol particles, composed in part of SOM, play important roles in climate and air quality by scattering/absorbing radiation and serving as cloud condensation nuclei (CCN). The magnitude of climate-relevant perturbations depends on particle chemical composition, hygroscopic growth, and phase state, among other factors. Herein, the hygroscopic influence on particle rebound and the phase state of particles composed of isoprene, toluene, and α-pinene secondary organic material (SOM) was studied. Particle rebound measurements were obtained from 5 to 95% RH using a three-arm impaction apparatus. The experimentally determined rebound fractions were compared with results from a model of the rebound process that took into account the particle kinetic energy, van der Waals forces, and RH-dependent capillary forces. Comparison of the experimental and modeled indicated particles softened due to water uptake. For low RH values, the model explained the rebound behavior for all studied SOMs. At higher RH values specific to each SOM, however, particle rebound was no longer observed, and the model did not capture this behavior. Calibration experiments using sucrose particles of variable known viscosities showed the transition from non-rebounding to rebounding particles occurred for viscosity values from 100 to 1 Pa s, corresponding to a transition from semisolid to liquid material. The implication of the differing RH-dependent behaviors among the SOMs is that each SOM has a specific and quantitatively different interaction with water. A linear correlation between rebound fraction and hygroscopic growth factor was demonstrated, implying that absorbed water volume is the governing factor of viscosity for the studied classes of SOM. The findings of this study suggest that both the chemical composition and the ambient relative humidity influence the phase state of secondary organic material.

  13. The effect of atmospheric pollution on building materials

    NASA Astrophysics Data System (ADS)

    Grossi, C. M.; Brimblecombe, P.

    2002-11-01

    This chapter surveys main effects of atmospheric pollution on building materials. It summarises these effects on stone, bricks, mortar, concrete, glass, metals (iron, zinc, copper, bronze, aluminium, lead and silver), polymers, paints and timber. Special attention is paid to stone because of its extensive use as building material in the cultural heritage. In general, main damaging agent is sulfur dioxide which leads to sulfation of many materials, particularly carbonate-bearing stones. However, the decline of sulfur dioxide in cities means that the recognition of the prime role of this pollutant presents something of a dilemma. It is increasingly necessary to consider other substances that can contribute to material decay e.g. nitrogen oxides, chlorides and ozone, either acting as synergistic to the sulfation reaction or as main decay agents, such as the case of aluminium and polymers. Particulate matter often from diesel vehicles can also accelerate the oxidation of SO2 on the surface (traditionally sulfur dioxide with Fe-rich particles) and blacken the materials surface in the case of soot. These processes contribute to the formation of black-crusts when embedded in the gypsum layer resulting from the material sulfation, but again the rate in the modem atmosphere is a matter of much research.

  14. Meteoric Material: An Important Component of Planetary Atmospheres

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Moses, Julianne I.; Pesnell, W. Dean; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Interplanetary dust particles (IDPs) interact with all planetary atmospheres and leave their imprint as perturbations of the background atmospheric chemistry and structure. They lead to layers of metal ions that can become the dominant positively charged species in lower ionospheric regions. Theoretical models and radio occultation measurements provide compelling evidence that such layers exist in all planetary atmospheres. In addition IDP ablation products can affect neutral atmospheric chemistry, particularly at the outer planets where the IDPs supply oxygen compounds like water and carbon dioxide to the upper atmospheres. Aerosol or smoke particles from incomplete ablation or recondensation of ablated IDP vapors may also have a significant impact on atmospheric properties.

  15. Evolution of Soot Particle Morphology and Mixing State in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Mazzoleni, C.; China, S.; Sharma, N.; Gorkowski, K.; Dubey, M.; Aiken, A. C.; Zaveri, R. A.; Salvadori, N.; Chakrabarty, R. K.; Moosmuller, H.; Onasch, T. B.; Herndon, S.; Williams, L. R.; Liu, S.; Dzepina, K.; Helmig, D.; Hueber, J.; Fialho, P. J.; Mazzoleni, L. R.; kumar, S.; Dziobak, M.; Wright, K.

    2013-12-01

    Soot particles (aka black carbon) impact the environment and climate by affecting Earth's radiation balance, cloud microphysics, and atmospheric chemistry. The complex morphology and mixing state of soot particles influence their optical properties and therefore their radiative forcing, the particles' transport, lifecycle, and heterogeneous chemistry. How soot morphology and mixing state alter during transport from the source to remote areas is still not well understood. While aging, soot particles can change shape, oxidize and mix, and become coated by organic and inorganic materials. In this study, we investigate the morphological and mixing state evolution of single soot particles in different stages of their 'life' in the atmosphere. This analysis will include an overview of several samples collected in various locations and atmospheric conditions: 1) particles freshly emitted near freeway on-ramps in Southern Michigan (USA); 2) particles emitted in two biomass burning events in New Mexico (USA), one close to the sampling location and another hundreds of miles away; 3) particles in the urban atmosphere of Mexico City and in the uplifted boundary layer captured on the top of the Pico de Tres Padres Mountain (on the north edge of Mexico City); 4) particles collected in the Sacramento urban area and the Sierra Nevada foothills (CA, USA); 5) particles collected in Detling (UK), and mostly transported from London, and 6) long-range transported particles in the free troposphere and collected at the Pico Mountain Observatory, located near the top of the Pico Volcano in the Azores (Portugal). We analyzed a large number of individual particles using electron microscopy and X-ray spectroscopy followed by image analysis. The projected structural properties of soot particles were characterized using size (maximum length, maximum width, and area equivalent diameter) and shape descriptors (e.g., aspect ratio, roundness, and convexity). The particle mass-fractal dimensions were determined using the ensemble method. The mixing state was analyzed by classifying soot particles based on visual inspection of coating and morphology. Soot particles freshly emitted by anthropogenic sources show less coating and more open chain-like structures; on the other hand biomass burning and long-range transported soot particles appear to be mostly coated and exhibit very compacted shapes. However, soot processing in urban atmospheres results in a complex mixture of coated and uncoated particles with a variety of morphologies and mixing states.

  16. Black carbon particles in the urban atmosphere in Beijing

    NASA Astrophysics Data System (ADS)

    Wang, Gengchen; Bai, Jianhui; Kong, Qinxin; Emilenko, Alexander

    2005-09-01

    A study of the concentration of black carbon particles and its variation in the urban atmosphere has been carried out since 1996 in the Beijing area. The measurements were done in the late autumn and early winter each year, the period before and after domestic heating activities begin. The results show the presence of black carbon particles at the high level that vary over a large range in the urban atmosphere in Beijing. The mean value of daily average concentration for the whole observation period of 1996 2004 is 20.0 μg m-3. An evident decrease of black carbon particle concentration in the Beijing area is observed after 2000, and the daily average concentration of black carbon particles is estimated to be 16.0 μg m-3 with a variation range of 2.10 50.50 μg m-3 for the period of 2000 2004. The observation method and main variation behavior characteristics of black carbon particles in the urban atmosphere in the Beijing area are given and discussed.

  17. Atmospheric Condensational Properties of Ultrafine Chain and Fractal Aerosol Particles

    NASA Technical Reports Server (NTRS)

    Marlow, William H.

    1997-01-01

    The purpose for the research sponsored by this grant was to lay the foundations for qualitative understanding and quantitative description of the equilibrium vapor pressure of water vapor over the irregularly shaped, carbonaceous particles that are present in the atmosphere. This work apparently was the first systematic treatment of the subject. Research was conducted in two complementary components: 1. Calculations were performed of the equilibrium vapor pressure of water over particles comprised of aggregates of spheres in the 50-200 nm radius range. The purposes of this work were two-fold. First, since no systematic treatment of this subject had previously been conducted, its availability would be directly useful for quantitative treatment for a limited range of atmospheric aerosols. Second, it would provide qualitative indications of the effects of highly irregular particle shape on equilibrium vapor pressure of aggregates comprised of smaller spheres.

  18. Atmospheric science: Sea-spray particles cause freezing in clouds

    NASA Astrophysics Data System (ADS)

    Russell, Lynn M.

    2015-09-01

    Ice clouds in marine regions at high latitudes might form in warmer and drier air than was previously believed because of freezing induced by airborne particles that contain organic materials from ocean surface waters. See Letter p.234

  19. Heterogeneous ice nucleation and water uptake by field-collected atmospheric particles below 273 K

    NASA Astrophysics Data System (ADS)

    Wang, Bingbing; Laskin, Alexander; Roedel, Tobias; Gilles, Mary K.; Moffet, Ryan C.; Tivanski, Alexei V.; Knopf, Daniel A.

    2011-11-01

    Ice formation induced by atmospheric particles through heterogeneous nucleation is not well understood. Onset conditions for heterogeneous ice nucleation and water uptake by particles collected in Los Angeles and Mexico City were determined as a function of temperature (200-273 K) and relative humidity with respect to ice (RHice). Four dominant particle types were identified including soot associated with organics, soot with organic and inorganics, inorganic particles of marine origin coated with organic material, and Pb/Zn-containing particles apportioned to emissions relevant to waste incineration. Single particle characterization was provided by micro-spectroscopic analyses using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Above 230 K, significant differences in onsets of water uptake and immersion freezing of different particle types were observed. Below 230 K, particles exhibited high deposition ice nucleation efficiencies and formed ice atRHicewell below homogeneous ice nucleation limits. The data suggest that water uptake and immersion freezing are more sensitive to changes in particle chemical composition compared to deposition ice nucleation. The data demonstrate that anthropogenic and marine influenced particles, exhibiting various chemical and physical properties, possess distinctly different ice nucleation efficiencies and can serve as efficient IN at atmospheric conditions typical for cirrus and mixed-phase clouds.

  20. Heterogeneous ice nucleation and water uptake by field-collected atmospheric particles below 273 K

    NASA Astrophysics Data System (ADS)

    Wang, Bingbing; Laskin, Alexander; Roedel, Tobias; Gilles, Mary K.; Moffet, Ryan C.; Tivanski, Alexei V.; Knopf, Daniel A.

    2012-09-01

    Ice formation induced by atmospheric particles through heterogeneous nucleation is not well understood. Onset conditions for heterogeneous ice nucleation and water uptake by particles collected in Los Angeles and Mexico City were determined as a function of temperature (200-273 K) and relative humidity with respect to ice (RHice). Four dominant particle types were identified including soot associated with organics, soot with organic and inorganics, inorganic particles of marine origin coated with organic material, and Pb/Zn-containing particles apportioned to emissions relevant to waste incineration. Single particle characterization was provided by micro-spectroscopic analyses using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Above 230 K, significant differences in onsets of water uptake and immersion freezing of different particle types were observed. Below 230 K, particles exhibited high deposition ice nucleation efficiencies and formed ice atRHicewell below homogeneous ice nucleation limits. The data suggest that water uptake and immersion freezing are more sensitive to changes in particle chemical composition compared to deposition ice nucleation. The data demonstrate that anthropogenic and marine influenced particles, exhibiting various chemical and physical properties, possess distinctly different ice nucleation efficiencies and can serve as efficient IN at atmospheric conditions typical for cirrus and mixed-phase clouds.

  1. The atmospheric radiation response to solar-particle-events.

    PubMed

    O'Brien, K; Sauer, H H

    2003-01-01

    High-energy solar particles, produced in association with solar flares and coronal mass ejections, occasionally bombard the earth's atmosphere. resulting in radiation intensities additional to the background cosmic radiation. Access of these particles to the earth's vicinity during times of geomagnetic disturbances are not adequately described by using static geomagnetic field models. These solar fluxes are also often distributed non uniformly in space, so that fluxes measured by satellites obtained at great distances from the earth and which sample large volumes of space around the earth cannot be used to predict fluxes locally at the earth's surface. We present here a method which uses the ground-level neutron monitor counting rates as adjoint sources of the flux in the atmosphere immediately above them to obtain solar-particle effective dose rates as a function of position over the earth's surface. We have applied this approach to the large September 29-30, 1989 ground-level event (designated GLE 42) to obtain the magnitude and distribution of the solar-particle effective dose rate from an atypically large event. The results of these calculations clearly show the effect of the softer particle spectra associated with solar particle events, as compared with galactic cosmic rays, results in a greater sensitivity to the geomagnetic field, and, unlike cosmic rays, the near-absence of a "knee" near 60 degrees geomagnetic latitude. PMID:14727666

  2. Particle motion in atmospheric boundary layers of Mars and Earth

    NASA Technical Reports Server (NTRS)

    White, B. R.; Iversen, J. D.; Greeley, R.; Pollack, J. B.

    1975-01-01

    To study the eolian mechanics of saltating particles, both an experimental investigation of the flow field around a model crater in an atmospheric boundary layer wind tunnel and numerical solutions of the two- and three-dimensional equations of motion of a single particle under the influence of a turbulent boundary layer were conducted. Two-dimensional particle motion was calculated for flow near the surfaces of both Earth and Mars. For the case of Earth both a turbulent boundary layer with a viscous sublayer and one without were calculated. For the case of Mars it was only necessary to calculate turbulent boundary layer flow with a laminar sublayer because of the low values of friction Reynolds number; however, it was necessary to include the effects of slip flow on a particle caused by the rarefied Martian atmosphere. In the equations of motion the lift force functions were developed to act on a single particle only in the laminar sublayer or a corresponding small region of high shear near the surface for a fully turbulent boundary layer. The lift force functions were developed from the analytical work by Saffman concerning the lift force acting on a particle in simple shear flow.

  3. Materials characterisation with the associated particle technique

    SciTech Connect

    Perot, Bertrand; Carasco, Cedric; Deyglun, Clement; Eleon, Cyrille; Mariani, Alain; Ma, Jean-Luc

    2012-07-01

    Since the last past years, the Nuclear Measurement Laboratory of CEA Cadarache, France, together with Partners from European and National projects, has been studying the application of fast neutron interrogation with the Associated Particle Technique for material identification in different areas of homeland and maritime security, and for the characterisation of the materials constituting radioactive waste. Fast 14 MeV neutrons are produced from the H-3(H-2,n)alpha fusion reaction in a sealed tube neutron generator embedding an alpha detector. The alpha particle is used to tag neutron direction and emission time, thus allowing the electronic selection of neutron-induced gamma spectra in the voxels of interest. Gamma rays emitted by tagged neutron interactions on the present nuclei (C, O, N, Fe, Al, Si, Cl, etc.) are recorded with spectroscopic detectors and analysed to determine elemental proportions, thus allowing material identification. Investigations have been conducted for the detection of explosives, illicit drugs and contraband materials in cargo containers, for the inspection of objects lying on the sea floor suspected to contain explosives like mines, bombs, torpedoes, etc., for the recognition of an improvised chemical device, and for material identification in radioactive waste packages. Recently the detection of special nuclear materials is being investigated using time correlation analysis between induced fission particles, instead of gamma-ray spectroscopy. The paper presents an overview of these studies and last results. (authors)

  4. Impact of aerosols and atmospheric particles on plant leaf proteins

    NASA Astrophysics Data System (ADS)

    Yan, Xing; Shi, Wen Z.; Zhao, Wen J.; Luo, Na N.

    2014-05-01

    Aerosols and atmospheric particles can diffuse and absorb solar radiation, and directly affect plant photosynthesis and related protein expression. In this study, for the first time, we performed an extensive investigation of the effects of aerosols and atmospheric particles on plant leaf proteins by combining Geographic Information System and proteomic approaches. Data on particles with diameters of 0.1-1.0 ?m (PM1) from different locations across the city of Beijing and the aerosol optical depth (AOD) over the past 6 years (2007-2012) were collected. In order to make the study more reliable, we segregated the influence of soil pollution by measuring the heavy metal content. On the basis of AOD and PM1, two regions corresponding to strong and weak diffuse solar radiations were selected for analyzing the changes in the expression of plant proteins. Our results demonstrated that in areas with strong diffuse solar radiations, plant ribulose bisphosphate carboxylase was expressed at higher levels, but oxygen evolved in enhancer protein and light-harvesting complex II protein were expressed at lower levels. The expression of ATP synthase subunit beta and chlorophyll a-b binding protein were similar in both regions. By analyzing the changes in the expression of these leaf proteins and their functions, we conclude that aerosols and atmospheric particles stimulate plant photosynthesis facilitated by diffuse solar radiations.

  5. Atmospheric cosmic rays and solar energetic particles at aircraft altitudes.

    PubMed

    O'Brien, K; Friedberg, W; Sauer, H H; Smart, D F

    1996-01-01

    Galactic cosmic rays, which are thought to be produced and accelerated by a variety of mechanisms in the Milky Way galaxy, interact with the solar wind, the earth's magnetic field, and its atmosphere to produce hadron, lepton, and photon fields at aircraft altitudes that are quite unlike anything produced in the laboratory. The energy spectra of these secondary particles extend from the lowest possible energy to energies over an EeV. In addition to cosmic rays, energetic particles, generated on the sun by solar flares or coronal mass ejections, bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as cosmic rays. The authors have calculated atmospheric cosmic-ray angular fluxes, spectra, scalar fluxes, and ionization, and compared them with experimental data. Agreement with these data is seen to be good. These data have been used to calculate equivalent doses in a simplified human phantom at aircraft altitudes and the estimated health risks to aircraft crews. The authors have also calculated the radiation doses from several large solar energetic particle events (known as GLEs, or Ground Level Events), which took place in 1989, including the very large event known as GLE 42, which took place on September 29th and 30th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory. Unfortunately, there are essentially no experimental data with which to compare these calculations. PMID:11542509

  6. Heterogeneous ice nucleation and water uptake by field-collected atmospheric particles below 273 K

    SciTech Connect

    Wang, Bingbing; Laskin, Alexander; Roedel, Tobias R.; Gilles, Marry K.; Moffet, Ryan C.; Tivanski, Alexei V.; Knopf, Daniel A.

    2012-09-25

    Atmospheric ice formation induced by particles with complex chemical and physical properties through heterogeneous nucleation is not well understood. Heterogeneous ice nucleation and water uptake by ambient particles collected from urban environments in Los Angeles and Mexico City are presented. Using a vapour controlled cooling system equipped with an optical microscopy, the range of onset conditions for ice nucleation and water uptake by the collected particles was determined as a function of temperature (200{273 K) and relative humidity with respect to ice (RHice) up to water saturation. Three distinctly different types of authentic atmospheric particles were investigated including soot particles associated with organics/inorganics, inorganic particles of marine origin coated with organic material, and Pb/Zn containing inorganic particles apportioned to anthropogenic emissions relevant to waste incineration. Single particle characterization was provided by micro-spectroscopic analyses using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption ne structure spectroscopy (STXM/NEXAFS). Above 230 K, signicant differences in water uptake and immersion freezing effciencies of the different particle types were observed. Below 230 K, the particles exhibited high deposition ice nucleation effciencies and formed ice at RHice values well below homogeneous ice nucleation limits. The data show that the chemical composition of these eld{collected particles plays an important role in determining water uptake and immersion freezing. Heterogeneous ice nucleation rate coeffcients, cumulative ice nuclei (IN) spectrum, and IN activated fraction for deposition ice nucleation are derived. The presented ice nucleation data demonstrate that anthropogenic and marine particles comprising of various chemical and physical properties exhibit distinctly different ice nucleation effciencies and can serve as effcient IN at atmospheric conditions typical for cirrus and mixed phase clouds. This indicates a potential link between human activities and cloud formation, and thus climate.

  7. Discrimination of airborne material particles from light scattering (TAOS) patterns

    NASA Astrophysics Data System (ADS)

    Crosta, Giovanni F.; Pan, Yong-Le; Videen, Gorden; Aptowicz, Kevin B.; Chang, Richard K.

    2013-05-01

    Two-dimensional angle-resolved optical scattering (TAOS) is an experimental method which collects the intensity pattern of monochromatic light scattered by a single, micron-sized airborne particle. In general, the interpretation of these patterns and the retrieval of the particle refractive index, shape or size alone, are difficult problems. The solution proposed herewith relies on a learning machine (LM): rather than identifying airborne particles from their scattering patterns, TAOS patterns themselves are classified. The LM consists of two interacting modules: a feature extraction module and a linear classifier. Feature extraction relies on spectrum enhancement, which includes the discrete cosine Fourier transform and non-linear operations. Linear classification relies on multivariate statistical analysis. Interaction enables supervised training of the LM. The application described in this article aims at discriminating the TAOS patterns of single bacterial spores (Bacillus subtilis) from patterns of atmospheric aerosol and diesel soot particles. The latter are known to interfere with the detection of bacterial spores. Classification has been applied to a data set with more than 3000 TAOS patterns from various materials. Some classification experiments are described, where the size of training sets has been varied as well as many other parameters which control the classifier. By assuming all training and recognition patterns to come from the respective reference materials only, the most satisfactory classification result corresponds to ? 20% false negatives from Bacillus subtilis particles and <= 11% false positives from environmental and diesel particles.

  8. Mixing state of atmospheric particles over the North China Plain

    NASA Astrophysics Data System (ADS)

    Zhang, S. L.; Ma, N.; Kecorius, S.; Wang, P. C.; Hu, M.; Wang, Z. B.; Größ, J.; Wu, Z. J.; Wiedensohler, A.

    2016-01-01

    In this unique processing study, the mixing state of ambient submicron aerosol particles in terms of hygroscopicity and volatility was investigated with a Hygroscopicity Tandem Differential Mobility Analyzer and a Volatility Tandem Differential Mobility Analyzer. The measurements were conducted at a regional atmospheric observational site in the North China Plain (NCP) from 8 July to 9 August, 2013. Multimodal patterns were observed in the probability density functions of the hygroscopicity parameter κ and the shrink factor, indicating that ambient particles are mostly an external mixture of particles with different hygroscopicity and volatility. Linear relationships were found between the number fraction of hydrophobic and non-volatile populations, reflecting the dominance of soot in hydrophobic and non-volatile particles. The number fraction of non-volatile particles is lower than that of hydrophobic particles in most cases, indicating that a certain fraction of hydrophobic particles is volatile. Distinct diurnal patterns were found for the number fraction of the hydrophobic and non-volatile particles, with a higher level at nighttime and a lower level during the daytime. The result of air mass classification shows that aerosol particles in air masses coming from north with high moving speed have a high number fraction of hydrophobic/non-volatile population, and are more externally mixed. Only minor differences can be found between the measured aerosol properties for the rest of the air masses. With abundant precursor in the NCP, no matter where the air mass originates, as far as it stays in the NCP for a certain time, aerosol particles may get aged and mixed with newly emitted particles in a short time.

  9. Modelling of externally mixed particles in the atmosphere

    NASA Astrophysics Data System (ADS)

    ZHU, Shupeng; Sartelet, Karine; Seigneur, Christian

    2014-05-01

    Particles present in the atmosphere have significant impacts on climate as well as on human health. Thus, it is important to accurately simulate and forecast their concentrations. Most commonly used air quality models assume that particles are internally mixed, largely for computational reasons. However, this assumption is disproved by measurements, especially close to sources. In fact, the externally-mixed properties of particles are important for aerosol source identification, radiative effects and particle evolution. In this study, a new size-composition resolved aerosol model is developed. It can solve the aerosol dynamic evolution for external mixtures taking into account the processes of coagulation, condensation and nucleation. Both the size of particles and the mass fraction of each chemical compound are discretized. For a given particle size, particles of different chemical composition may co-exist. Aerosol dynamics is solved in each grid cell by splitting coagulation and condensation/evaporation-nucleation processes. For the condensation/evaporation, surface equilibrium between gas and aerosol is calculated based on ISORROPIA and the newly developed H2O (Hydrophilic/Hydrophobic Organic) Model. Because size and chemical composition sections evolve during condensation/evaporation, concentrations need to be redistributed on fixed sections after condensation/evaporation to be able to use the model in 3 dimensions. This is done based on the numerical scheme HEMEN, which was initially developed for size redistribution. Chemical components can be grouped into several aggregates to reduce computational cost. The 0D model is validated by comparison to results obtained for internally mixed particles and the effect of mixing is investigated for up to 31 species and 4 aggregates. The model will be integrated into the air quality modeling platform POLYPHEMUS to investigate its performance in modeling air quality by comparing with observations during the MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) campaign in July 2009.

  10. Absorption and scattering of light by nonspherical particles. [in atmosphere

    NASA Technical Reports Server (NTRS)

    Bohren, C. F.

    1986-01-01

    Using the example of the polarization of scattered light, it is shown that the scattering matrices for identical, randomly ordered particles and for spherical particles are unequal. The spherical assumptions of Mie theory are therefore inconsistent with the random shapes and sizes of atmospheric particulates. The implications for corrections made to extinction measurements of forward scattering light are discussed. Several analytical methods are examined as potential bases for developing more accurate models, including Rayleigh theory, Fraunhoffer Diffraction theory, anomalous diffraction theory, Rayleigh-Gans theory, the separation of variables technique, the Purcell-Pennypacker method, the T-matrix method, and finite difference calculations.

  11. Quantitative ED-EPMA of Individual Particles and its Application for Characterization of Atmospheric Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Ro, C.

    2008-12-01

    An electron probe X-ray microanalysis (EPMA) technique using an energy-dispersive X-ray detector with an ultra-thin window, named low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements such as C, N, and O, as well as higher-Z elements that can be analyzed by conventional energy-dispersive EPMA (ED-EPMA). The quantitative determination of low-Z elements (using full Monte Carlo simulations, from the electron impact to the X-ray detection) in individual environmental particles has improved the applicability of single-particle analysis, especially in atmospheric environmental aerosol research; many environmentally important atmospheric particles, e.g. sulfates, nitrates, ammonium, and carbonaceous particles, contain low-Z elements. In addition, an expert system that can perform chemical speciation from the elemental composition data obtained by the low-Z particle EPMA has been developed. The low-Z particle EPMA was applied to characterize K-feldspar particle samples of which the chemical compositions are well defined by the use of various bulk analytical methods. Chemical compositions of the K-feldspar samples obtained from the low-Z particle EPMA turn out to be very close to those from bulk analyses. The low-Z particle EPMA technique has been applied for the characterization of atmospheric aerosol particle samples, including Asian dust, urban, and indoor particulate samples: (1) The extent of chemical modification of Asian dust particles sampled in Chuncheon and Incheon, Korea, during several Asian dust storm events occurred in 2002-2006 was investigated. Mixing of Asian dust with air pollutants and sea-salts strongly depends on the characteristics of Asian dust storm events such as air-mass backward trajectories. For instance, no significant chemical modification of mineral dust corresponded to fast moving air-masses at high altitudes. Inversely, extensive chemical modification was correlated with longer residence times over the continent (interaction with anthropogenic emissions) and in marine atmosphere (coagulation with deliquesced sea-salts). (2) Six urban aerosol samples collected in a megacity of Korea, namely Incheon, during a period of March 9-15, 2006 were characterized. Many different particle types, such as "soil-derived particles", "reacted sea-salts", "reacted CaCO3-containing particles", "genuine sea-salts", "reacted sea-salts + others", "Fe-containing particles", "anthropogenic organics", (NH4)2SO4, "K-containing particles", and "fly ashes", can be identified and their emission source, transport, and reactivity in the air can be elucidated. Also, different characteristics of the samples were clearly revealed. (3) When the technique was applied for the characterization of indoor subway station aerosols, it was observed that iron-containing particles are predominant. Agglomerated iron-containing particles, nano-size particles adsorbed on the other particles, and partially oxidized iron particles were frequently encountered, which implies that Iron-containing particles are generated mainly by the friction between break pad, wheel, and rails.

  12. Water Absorption by Atmospheric Organic Particles: Evidence, Causes and Simulations

    NASA Astrophysics Data System (ADS)

    Saxena, Pradeep

    The optical and chemical properties of atmospheric fine particles and their ability to act as cloud condensation nuclei depend strongly upon their affinity for water. Laboratory experiments have shown that water-soluble sulfates and nitrates, which are major inorganic components of atmospheric fine particles, absorb water in an amount proportional to water vapor pressure. Analogous information about the interactions between water and organics is lacking. Moreover, the molecular composition of atmospheric particulate organics remains poorly characterized; information on the molecular composition of the water-soluble fraction is particularly sparse. Here we first analyze concurrent observations of particle chemical composition and water content from a continental nonurban (Grand Canyon) and an urban (Los Angeles) location to determine whether the water content of atmospheric particles is influenced by the presence of organics. We find that the aggregate hygroscopic properties of inorganic particles are altered substantially when organics are also present. For the nonurban location, organics enhance water absorption by inorganics. For the urban location, on the other hand, the net effect of organics is to diminish water absorption of the inorganics. Second, we identify specific compounds that are likely to contribute to the water-soluble fraction by juxtaposing published observations regarding the extraction characteristics and the molecular composition of atmospheric particulate organics with compound-specific solubility and condensibility for a wide variety of organics. We find that water-soluble organics, which constitute a substantial fraction of the total organic mass, include C2 to C7 multifunctional compounds (e.g. diacids, polyols, amino acids). Third, towards developing a simulation capability, we (1) synthesize published laboratory data to evaluate the water absorption behavior of multifunctional oxygenated organic compounds; and (2) test the reliability of the UNIFAC method for estimating water activities of aqueous organic solutions. Laboratory data show that multifunctional oxygenated compounds can absorb water over the entire range of relative humidities. For a wide variety of compounds (e.g., glycols, dicarboxylic acids, keto acids) and a wide range of solute concentrations (0 to over 90% by wt), we find that in most cases, water activities can be estimated within approximately 15% error.

  13. Morphology and mixing state of atmospheric particles: Links to optical properties and cloud processing

    NASA Astrophysics Data System (ADS)

    China, Swarup

    Atmospheric particles are ubiquitous in Earth's atmosphere and impact the environment and the climate while affecting human health and Earth's radiation balance, and degrading visibility. Atmospheric particles directly affect our planet's radiation budget by scattering and absorbing solar radiation, and indirectly by interacting with clouds. Single particle morphology (shape, size and internal structure) and mixing state (coating by organic and inorganic material) can significantly influence the particle optical properties as well as various microphysical processes, involving cloud-particle interactions and including heterogeneous ice nucleation and water uptake. Conversely, aerosol cloud processing can affect the morphology and mixing of the particles. For example, fresh soot has typically an open fractal-like structure, but aging and cloud processing can restructure soot into more compacted shapes, with different optical and ice nucleation properties. During my graduate research, I used an array of electron microscopy and image analysis tools to study morphology and mixing state of a large number of individual particles collected during several field and laboratory studies. To this end, I investigated various types of particles such as tar balls (spherical carbonaceous particles emitted during biomass burning) and dust particles, but with a special emphasis on soot particles. In addition, I used the Stony Brook ice nucleation cell facility to investigate heterogeneous ice nucleation and water uptake by long-range transported particles collected at the Pico Mountain Observatory, in the Archipelago of the Azores. Finally, I used ice nucleation data from the SAAS (Soot Aerosol Aging Study) chamber study at the Pacific Northwest National Laboratory to understand the effects that ice nucleation and supercooled water processing has on the morphology of residual soot particles. Some highlights of our findings and implications are discussed next. We found that the morphology of fresh soot emitted by vehicles depends on the driving conditions (i.e.; the vehicle specific power). Soot emitted by biomass burning is often heavily coated by other materials while processing of soot in urban environment exhibits complex mixing. We also found that long-range transported soot over the ocean after atmospheric processing is very compacted. In addition, our results suggest that freezing process can facilitate restructuring of soot and results into collapsed soot. Furthermore, numerical simulations showed strong influence on optical properties when fresh open fractal-like soot evolved to collapsed soot. Further investigation of long-range transported aged particles exhibits that they are efficient in water uptake and can induce ice nucleation in colder temperature. Our results have implications for assessing the impact of the morphology and mixing state of soot particles on human health, environment and climate. Our findings can provide guidance to numerical models such as particle-resolved mixing state models to account for, and better understand, vehicular emissions and soot evolution since its emission to atmospheric processing in urban environment and finally in remote regions after long-range transport. Morphology and mixing state information can be used to model observational-constrained optical properties. The details of morphology and mixing state of soot particles are crucial to assess the accuracy of climate models in describing the contribution of soot radiative forcing and their direct and indirect climate effects. Finally, our observations of ice nucleation ability by aged particles show that nucleated particles are internally mixed and coated with several materials.

  14. How quickly do cloud droplets form on atmospheric particles?

    NASA Astrophysics Data System (ADS)

    Ruehl, C. R.; Chuang, P. Y.; Nenes, A.

    2008-02-01

    The influence of aerosols on cloud properties is an important modulator of the climate system. Traditional Köhler theory predicts the equilibrium concentration of cloud condensation nuclei (CCN); however, it is not known to what extent particles exist in the atmosphere that may be prevented from acting as CCN by kinetic limitations. We measured the rate of cloud droplet formation on atmospheric particles sampled at four sites across the United States during the summer of 2006: Great Smoky Mountain National Park, TN; Bondville, IL; Houston, TX; and the Atmospheric Radiation Measurement Program Southern Great Plains site near Lamont, OK. We express droplet growth rates with the mass accommodation coefficient (α), and report values of α measured in the field normalized to the mean α measured for lab-generated ammonium sulfate (AS) particles (i.e., α'=α/αAS). Overall, 59% of ambient CCN grew at a rate similar to AS. We report the fraction of CCN that were "low-α' " (α'<10-1, corresponding to α<1.5×10-2). Of the 16 days during which these measurements were made, 8 had relatively few low-α' CCN (<16%), 6 had moderate low-α' fractions (27% to 59%), and 2 had large low-α' fractions (>82% during at least one ~30 min period). Day to day variability was greatest in Tennessee and Illinois, and low-α' particles were most prevalent on days when back trajectories suggested that air was arriving from aloft. The highest fractions of low-α' CCN in Houston and Illinois occurred around local noon, and decreased later in the day. These results suggest that for some air masses, accurate quantification of CCN concentrations may need to account for kinetic limitations.

  15. Investigations of organic and microbiological atmospheric ice nucleating particles (Invited)

    NASA Astrophysics Data System (ADS)

    DeMott, P. J.; Hill, T. C.; Tobo, Y.; Prenni, A. J.; McMeeking, G. R.; Levin, E. J.; McCluskey, C.; Huffman, J. A.; Mason, R.; Bertram, A. K.; Kreidenweis, S. M.

    2013-12-01

    Measurements in a number of laboratory and field campaigns have offered the opportunity to compare and contrast ice nucleation by soil-and plant-based inorganic, organic, and microbiological particles versus ice nucleating particles (INP) actually sampled in the atmosphere. This presentation reviews these recent studies. Plants support sometimes prodigious populations of INA bacteria as well as fungi and other potential biological ice nucleating particles, such as fragments of plant tissues themselves. The means of release of plant-sourced INP to the atmosphere is not fully documented, but our recent studies have found clear cases of release of ice nuclei from disturbances such as rain, both in forests and over grasslands, and harvesting. Composition of such ice nuclei in air has been inferred at these times based on simultaneous measurements of ice nuclei and biological aerosols. At quiescent times, measurements of the labile fraction of ice nucleating particles in air over agricultural regions suggest that organic and possibly microbiological organisms dominate ice nuclei populations, but INA bacteria are only selective and modest contributors at the warmest activation temperatures. Our results therefore suggest the presence of a spectrum of biological and organic ice nucleating particles over land regions. The ice nucleating activity of mineral soils is well documented and the presence of these particles in air is certain on the basis of many measurement campaigns which identified mineral particles to represent up to half or more of ice nuclei sampled in parts of the free troposphere. Our recent measurements have also documented a clear organic ice nucleating particle source within arable, sagebrush, grassland and forest soils, a source that may dominate over the mineral ice nuclei in such soils. Investigations of their compositions will be described. These ice nuclei are strongly resistant to heat, and may represent a separate population and source compared to the labile ice nuclei found in air over agricultural regions. While these soil-based ice nuclei must at times be lofted into the free troposphere and may represent some proportion of carbonaceous ice nuclei detected via electron microscopy in previous ambient sampling, we have not presently directly confirmed the presence of these ice nuclei in ambient air. Depending on available time, results regarding organic contributions of ice nucleating particles from biomass burning and oceanic sources will also be discussed.

  16. Field and Laboratory Studies of Reactions between Atmospheric Water Soluble Organic Acids and Inorganic Particles

    SciTech Connect

    Wang, Bingbing; Kelly, Stephen T.; Sellon, Rachel E.; Shilling, John E.; Tivanski, Alexei V.; Moffet, Ryan C.; Gilles, Mary K.; Laskin, Alexander

    2013-06-25

    Atmospheric inorganic particles undergo complex heterogeneous reactions that change their physicochemical properties. Depletion of chloride in sea salt particles was reported in previous field studies and was attributed to the acid displacement of chlorides with inorganic acids, such as nitric and sulfuric acids [1-2]. Recently, we showed that NaCl can react with water soluble organic acids (WSOA) and release gaseous hydrochloric acid (HCl) resulting in formation of organic salts [3]. A similar mechanism is also applicable to mixed WSOA/nitrate particles where multi-phase reactions are driven by the volatility of nitric acid. Furthermore, secondary organic material, which is a complex mixture of carboxylic acids, exhibits the same reactivity towards chlorides and nitrates. Here, we present a systematic study of reactions between atmospheric relevant WSOA, SOM, and inorganic salts including NaCl, NaNO3, and Ca(NO3)2 using complementary micro-spectroscopy analysis.

  17. Properties of submicron particles in Atmospheric Brown Clouds

    NASA Astrophysics Data System (ADS)

    Adushkin, V. V.; Chen, B. B.; Dubovskoi, A. N.; Friedrich, F.; Pernik, L. M.; Popel, S. I.; Weidler, P. G.

    2010-05-01

    The Atmospheric Brown Clouds (ABC) is an important problem of this century. Investigations of last years and satellite data show that the ABC (or brown gas, smog, fog) cover extensive territories including the whole continents and oceans. The brown gas consists of a mixture of particles of anthropogenic sulfates, nitrates, organic origin, black carbon, dust, ashes, and also natural aerosols such as sea salt and mineral dust. The brown color is a result of absorption and scattering of solar radiation by the anthropogenic black carbon, ashes, the particles of salt dust, and nitrogen dioxide. The investigation of the ABC is a fundamental problem for prevention of degradation of the environment. At present in the CIS in-situ investigations of the ABC are carried out on Lidar Station Teplokluchenka (Kyrgyz Republic). Here, we present the results of experimental investigation of submicron (nanoscale) particles originating from the ABC and the properties of the particles. Samples of dust precipitating from the ABC were obtained at the area of Lidar Station Teplokluchenka as well as scientific station of the Russian Academy of Sciences near Bishkek. The data for determination of the grain composition were obtained with the aid of the scanning electron microscopes JEOL 6460 LV and Philips XL 30 FEG. Analysis of the properties of the particles was performed by means of the X-ray diffraction using diffractometer Siemens D5000. The images of the grains were mapped. The investigation allows us to get (after the image processing) the grain composition within the dust particle size range of 60 nm to 700 μm. Distributions of nano- and microscale particles in sizes were constructed using Rozin-Rammler coordinates. Analysis of the distributions shows that the ABC contain submicron (nanoscale) particles; 2) at higher altitudes the concentration of the submicron (nanoscale) particles in the ABC is higher than at lower altitudes. The chemical compositions of the particles are shown to be close to those typical for the ABC. We present also the results of the study of morphology and mineralogical composition of the obtained particles as well as their magnetic properties. This study was supported by the Division of Earth Sciences, Russian Academy of Sciences (research program "Nanoscale particles in nature and technogenic products: conditions of existence, physical and chemical properties, and mechanisms of formation") and by ISTC (project No. KR-1522).

  18. Parameters of Dust Particles in the Martian Atmosphere

    NASA Astrophysics Data System (ADS)

    Dlugach, Zh. M.; Morozhenko, A. V.

    2001-11-01

    A critical analysis of the methods and results of estimating the optical thickness of the dust component in the Martian atmosphere τ_0, the particle size r_0, and the imaginary part of the refractive index n_ihas shown the following. (1) Observational data on the brightness distribution over the Martian disk as well as the phase dependences of diffusely reflected light and the azimuthal dependences of diffusely transmitted light are most appropriate to use only for verifying the reliability of the aerosol parameters determined by other methods. (2) If the morning and evening fogs in the atmosphere are disregarded, the Bouguer-Lambert-Beer method used to analyze the solar-brightness attenuation measured on the planetary surface yields overestimated extraatmospheric solar intensity I_0and atmospheric optical depth τ_0. At the Viking 1landing site, I_0and τ_0could be overestimated by a factor of 1.7 and by 0.35, respectively. (3) The aerosol size determined by analyzing measurements of the azimuthal dependences for the Martian sky brightness at low elevations of the Sun most likely corresponds to the fog particles. (4) If overestimated values of I_0were used to standardize the observations of the solar radiation transmitted by the Martian atmosphere, then n_iwere also overestimated; using overestimated τ_0also affected the reliability of the latter. (5) The problem of reliability of the available τ_0and r_0estimates for periods of high atmospheric transparency is yet to be solved. For the highest activity of the dust storm in 1971, it was found that 4.5 <= r_0<= 7.5 μm for the lognormal particle size distribution with σ^2= 0.2 and the optical thickness of a dust cloud τ_0>= 15. (6) The spectral values of the apparent albedo of Mars measured in October 1971 at a phase angle of 42° in the spectral range 0.250 <= λ <= 0.717 allowed the imaginary part of the refractive index to be estimated in terms of a model of a dust cloud composed of spherical particles with the lognormal size distribution with r_0= 4.5 μm and σ^2= 0.2.

  19. Use of Atmospheric Glow Discharge Plasma to Modify Spaceport Materials

    NASA Astrophysics Data System (ADS)

    Trigwell, S.; Schuerger, A. C.; Buhler, C. R.; Calle, C. I.

    2006-03-01

    Atmospheric pressure glow discharge plasma was used to modify spaceport materials to render them compliant with KSC ESD standards. The plasma treatment both inhibited and enhanced the recovery of adhered bacteria depending upon the material.

  20. Ignition of a Combustible Atmosphere by Incandescent Carbon Wear Particles

    NASA Technical Reports Server (NTRS)

    Buckley, Donald H.; Swikert, Max A.; Johnson, Robert L.

    1960-01-01

    A study was made to determine whether carbon wear particles from carbon elements in sliding contact with a metal surface were sufficiently hot to cause ignition of a combustible atmosphere. In some machinery, electric potential differences and currents may appear at the carbon-metal interface. For this reason the effect of these voltages and currents on the ability of carbon wear particles to cause ignition was evaluated. The test specimens used in the investigation were carbon vanes taken from a fuel pump and flat 21-inch-diameter 2 metal disks (440-C stainless steel) representing the pump housing. During each experiment a vane was loaded against a disk with a 0.5-pound force, and the disk was rotated to give a surface speed of 3140 feet per minute. The chamber of the apparatus that housed the vane and the disk was filled with a combustible mixture of air and propane. Various voltages and amperages were applied across the vane-disk interface. Experiments were conducted at temperatures of 75, 350, 400, and 450 F. Fires were produced by incandescent carbon wear particles obtained at conditions of electric potential as low as 106 volts and 0.3 ampere at 400 F. Ignitions were obtained only with carbon wear particles produced with an electric potential across the carbon-vane-disk interface. No ignitions were obtained with carbon wear particles produced in the absence of this potential; also, the potential difference produced no ignitions in the absence of carbon wear particles. A film supplement showing ignition by incandescent wear particles is available.

  1. How quickly do cloud droplets form on atmospheric particles?

    NASA Astrophysics Data System (ADS)

    Ruehl, C. R.; Chuang, P. Y.; Nenes, A.

    2007-10-01

    The influence of aerosols on cloud properties is an important modulator of the climate system. Traditional Köhler theory predicts the equilibrium concentration of cloud condensation nuclei (CCN); however, it is not known to what extent particles exist in the atmosphere that may be prevented from acting as CCN by kinetic limitations. We measured the rate of cloud droplet formation on atmospheric particles sampled at four sites across the United States during the summer of 2006: Great Smoky Mountain National Park, TN; Bondville, IL; Houston, TX; and the Atmospheric Radiation Measurement Program Southern Great Plains site near Lamont, OK. We express droplet growth rates with the mass accommodation coefficient (α), and report values of α measured in the field normalized to the mean α measured for lab-generated ammonium sulfate (AS) particles (i.e., α'=α/αAS). Overall, 61% of ambient CCN grew at a rate similar to AS. We report the fraction of CCN that were "low-α'" (α'<10-0.33). Of the 16 days during which these measurements were made, 7 had relatively few low-α'CCN (<16%), 7 had moderate low-α' fractions (31% to 62%), and 2 had large low-α' fractions (>77% during at least one ~30 min period). Day to day variability was greatest in Tennessee and Illinois, and low-α' CCN were most prevalent on days when back trajectories suggested that air was arriving from aloft. The highest fractions of low-α' CCN in Houston and Illinois occurred around local noon, and decreased later in the day. These results suggest that for some air masses, accurate quantification of CCN concentrations may need to account for kinetic limitations.

  2. Chemistry of background atmospheric particles collected at Mauna Loa Observatory, Hawaii

    SciTech Connect

    Parrington, J.R.

    1984-01-01

    Mauna Loa Observatory, Hawaii, was selected as a remote northern hemisphere site from which to collect atmospheric particles for chemical analyses of background aerosols in the free troposphere of the northern hemisphere. An automatic digital sampling controller was designed and installed at this site to aid in the isolation of uncontaminated particles of the free troposphere, based on wind direction and speed, time-of-day and particle characteristics at the observatory. The three primary components measured on these background particles between 1979 and 1982 were sulfates, continentally derived crustal material and marine particles with average geometric mean concentrations of 240 ng/m/sup 3/, and 15 ng/m/sup 3/, respectively, during the months of July to mid-February. Other months showed a ten-fold increase in continental crustal material, geometric avg = 730 ng/m/sup 3/, (which has been traced to Asian deserts) and doubling of sulfate mass to 480 ng/m/sup 3/ while the marine mass showed no significant changes. The average geometric mean concentration of local basalt was determined to be 15 ng/m/sup 3/ in down-slope winds and, thus, does not represent a major interference to most studies at MLO as a majority of the crustal dust in the atmosphere, even in relatively clean periods, is transported over thousands of kilometers to the islands from continents surrounding the Pacific Ocean.

  3. Can Highly Oxidized Organics Contribute to Atmospheric New Particle Formation?

    PubMed

    Ortega, Ismael K; Donahue, Neil M; Kurtén, Theo; Kulmala, Markku; Focsa, Cristian; Vehkamäki, Hanna

    2016-03-10

    Highly oxidized organic molecules may play a critical role in new-particle formation within Earth's atmosphere along with sulfuric acid, which has long been considered as a key compound in this process. Here we explore the interactions of these two partners, using quantum chemistry to find the formation free energies of heterodimers and trimers as well as the fastest evaporation rates of (2,2) tetramers. We find that the heterodimers are more strongly bound than pure sulfuric acid dimers. Their stability correlates well with the oxygen to carbon ratio of the organics, their volatility, and the number of hydrogen bonds formed. Most of the stable trimers contain one sulfuric acid and two organics (1,2), whereas many (2,2) tetramers evaporate quickly, probably due to the stability of (1,2) clusters. This finding agrees with recent experimental studies that show how new-particle formation involving oxidized organics and sulfuric acid may be rate-limited by activation of (1,2) trimers, confirming the importance of this process in the atmosphere. PMID:26544764

  4. Particle hygroscopicity during atmospheric new particle formation events: implications for the chemical species contributing to particle growth

    NASA Astrophysics Data System (ADS)

    Wu, Z.; Birmili, W.; Poulain, L.; Poulain, L.; Merkel, M.; Fahlbusch, B.; van Pinxteren, D.; Herrmann, H.; Wiedensohler, A.

    2013-07-01

    This study examines the hygroscopicity of newly formed particles (diameters range 25-45 nm) during two atmospheric new particle formation (NPF) events in the German mid-level mountains during the Hill Cap Cloud Thuringia 2010 (HCCT-2010) field experiment. At the end of the NPF event involving clear particle growth, we measured an unusually high soluble particle fraction of 58.5% at 45 nm particle size. The particle growth rate contributed through sulfuric acid condensation only accounts for around 6.5% of the observed growth rate. Estimations showed that sulfuric acid condensation explained, however, only around 10% of that soluble particle fraction. Therefore, the formation of additional water-soluble matter appears imperative to explain the missing soluble fraction. Although direct evidence is missing, we consider water-soluble organics as candidates for this mechanism. For the case with clear growth process, the particle growth rate was determined by two alternative methods based on tracking the mode diameter of the nucleation mode. The mean particle growth rate obtained from the inter-site data comparison using Lagrangian consideration is 3.8 (± 2.6) nm h-1. During the same period, the growth rate calculated based on one site data is 5.0 nm h-1 using log-normal distribution function method. In light of the fact that considerable uncertainties could be involved in both methods, we consider both estimated growth rates consistent.

  5. State of mixture of atmospheric submicrometer black carbon particles and its effect on particulate light absorption

    NASA Astrophysics Data System (ADS)

    Naoe, Hiroaki; Hasegawa, Shuichi; Heintzenberg, Jost; Okada, Kikuo; Uchiyama, Akihiro; Zaizen, Yuji; Kobayashi, Eriko; Yamazaki, Akihiro

    The state of mixture of light-absorbing carbonaceous particles was investigated in relation to light absorption properties using electron microscopic examinations, black carbon (BC) analyses of quartz filter by thermal/optical reflectance (TOR) method, measurements with two continuous light-absorbing photometers at a suburban site of Tsukuba, about 60 km northeast of Tokyo. The volume fraction of water-soluble material ( ɛ) in individual particles is important for assessing particulate light-absorbing and/or scattering of atmospheric aerosols. The values of ɛ in BC particles were evaluated by electron micrographs before and after dialysis (extraction) of water-soluble material. The mass absorption coefficient (MAC in units of m 2 g -1) tended to increase with increasing the average ɛ in BC particles with the radius range of 0.05-0.5 μm. Thus, our results indicate that coatings of water-soluble material around BC particles can enhance the absorption of solar radiation. Moreover, the single scattering albedo (SSA) will increase because a large amount of coating material will scatter more light.

  6. The effects of solar particle events on the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Douglass, Anne R.; Meade, Paul E.

    1989-01-01

    Solar particle events (SPEs) have been investigated since the late 1960's for possible effects on the middle atmosphere. Solar protons from SPEs produce ionizations, dissociations, dissociative ionizations, and excitations in the middle atmosphere. The production of HO(x) and NO(x) and their subsequent effects on ozone can also be computed using energy deposition and photochemical models. The effects of SPE-produced HO(x) species on the odd nitrogen abundance of the middle atmosphere as well as the SPE-produced long term effects on ozone. Model computations indicate fairly good agreement with ozone data for the SPE-induced ozone depletion caused by NO(y) species connected with the August 1972 SPE. The model computations indicate that NO(y) will not be substantially changed over a solar cycle by SPEs. The changes are mainly at high latitudes and are on time scales of several months, after which the NO(y) drifts back to its ambient levels.

  7. Heterogeneous Chemical Transformation of Incident Exogenous Organic Material in Earth's Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Belle, C. L.; Kress, M. E.; Iraci, L. T.

    2009-12-01

    On average, 10^8 g of solar system debris impinges on the Earth system each day. It is estimated that a few percent of this material is carbonaceous in nature, yet the fate of this organic material once it enters our atmosphere is unexplored. Much of this incoming material arrives in the form of micrometeoroids which are large enough to suffer drag heating and volatilize their organic material. Preliminary work shows that the organic material contained in particles with diameters on the order of 10-100 um is expected to be volatilized at altitudes of 100-120 km. Observed species include aromatic compounds such as alkybenzenes, phenol, benzonitrile, naphthalene, and styrene. Once liberated, these molecules may be transformed by processes at the boundary of space, or may survive to be mixed throughout the atmosphere. Sulfuric acid particles exist in Earth's upper atmosphere, and organic compounds often react strongly with this acid. We will report the results of laboratory and theoretical investigations of the interaction of aromatic compounds with surrogate matrices which mimic upper atmospheric particles. These studies will explore how exogenous organic compounds are altered after liberation at altitudes near 100 km and will determine if they survive to reach the surface of the Earth, where they may have provided the starting materials for the evolution of life on Earth or on other bodies.

  8. Laboratory Studies of Hydrocarbon Nucleation on Tholin Particles and Thin Organic Films: Application to Titan's Atmosphere

    NASA Technical Reports Server (NTRS)

    Curtis, Daniel B.; Glandorf, David L.; Toon, Owen B.; Tolbert, Margaret A.; McKay, Christopher P.; Khare, Bishun N.

    2001-01-01

    Titan, Saturn's largest satellite, has a thick nitrogen/methane atmosphere. In Titan's lower atmosphere, methane is saturated or supersaturated with respect to nucleation and may form clouds. To better characterize the properties of Titan's methane clouds we have measured the saturation ratio required to obtain butane nucleation, S (sub crit), on Titan tholin material and organic films. We find a critical saturation ratio for butane on tholin particles of S (sub crit) = 1.40, suggesting high supersaturations are required for nucleation. If methane is similar to butane, we expect high supersaturations of methane as well. This could favor the formation of a small number of large particles, consistent with recent measurements of methane rain on Titan.

  9. Water and acid soluble trace metals in atmospheric particles

    NASA Technical Reports Server (NTRS)

    Lindberg, S. E.; Harriss, R. C.

    1983-01-01

    Continental aerosols are collected above a deciduous forest in eastern Tennessee and subjected to selective extractions to determine the water-soluble and acid-leachable concentrations of Cd, Mn, Pb, and Zn. The combined contributions of these metals to the total aerosol mass is 0.5 percent, with approximately 70 percent of this attributable to Pb alone. A substantial fraction (approximately 50 percent or more) of the acid-leachable metals is soluble in distilled water. In general, this water-soluble fraction increases with decreasing particle size and with increasing frequency of atmospheric water vapor saturation during the sampling period. The pattern of relative solubilities (Zn being greater than Mn, which is approximately equal to Cd, which is greater than Pb) is found to be similar to the general order of the thermodynamic solubilities of the most probable salts of these elements in continental aerosols with mixed fossil fuel and soil sources.

  10. Atmospheric particle size and composition measurements to support light extinction calculations over the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Chowdhury, Zohir; Hughes, Lara S.; Salmon, Lynn G.; Cass, Glen R.

    2001-11-01

    The size distribution and chemical composition of the atmospheric aerosol at the Kaashidhoo Climate Observatory (KCO) in the Republic of Maldives was determined during the winter northeast monsoon season to aid in determining the light scattering and light absorption properties of the aerosol particles in that region. These experiments were conducted over 8 two-day periods during February 11-26, 1999, using filter-based samplers and cascade impactors operated at ambient relative humidity which was in the range of 80-89% relative humidity over 83% of the period sampled. Fine particle concentrations (Da<1.8 μm) averaged 17.7(±0.22) μg m-3 and varied between 8.4(±0.33)-24.7(±0.21) μg m-3 over the period studied. Sulfate ion and carbonaceous aerosols are the largest contributors to the fine particle mass concentration, accounting for 33-37% and 26-27% of the fine mass, respectively. Calcium carbonate contributes 3% of the mass measured on the impactor stages. Ammonium, nitrate, and chloride ion account for 7-9, 1, and 0-1% of the fine particle mass, respectively. The residual mass of as yet undetermined fine particle material stands at 28-30%. Black elemental carbon particles contribute 6-11% of the fine particle mass concentration and dominate light absorption in the atmosphere at KCO (A. Eldering et al., unpublished manuscript, 2001). These fine particle concentrations are comparable to those found in major cities in the United States and are surprisingly high for a remote location such as the Maldive Islands, which is located downwind of the Indian subcontinent.

  11. Accelerated life testing of electronic devices by atmospheric particles: Why and how

    SciTech Connect

    Frankenthal, R.P.; Siconolfi, D.J.; Sinclair, J.D. )

    1993-11-01

    Research on atmospheric corrosion and degradation of electronic materials and assemblies is usually carried out without considering the potential effects of airborne submicron particles, most of which are potentially corrosive ionic compounds. Yet data show that, in many urban indoor environments, the mass concentration of these particles and their arrival rate at surfaces are comparable to the mass concentration and arrival rate of corrosive gases. It is shown here that experiments that ignore the effect of particles are not representative of degradation in real-world environments. In recognition of this deficiency, an accelerated life test chamber was developed to evaluate the effect of submicron ionic particles on electronic devices, circuit boards, and other assemblies. The characteristics of the chamber include (i) 0.01--1 [mu]m diam particles at a concentration [>=] 1 [times] 10[sup 10]/m[sup 3] (ii) parallel air flow at velocities up to 35m/min, and (iii) uniform and constant particle concentration. The average acceleration factor for particle deposition is 100.

  12. Particle deposition and clearance of atmospheric particles in the human respiratory tract during LACE 98

    NASA Astrophysics Data System (ADS)

    Bundke, U.; Hänel, G.

    2003-04-01

    During the LACE 98footnote{Lindenberg Aerosol Characterization Experiment, (Germany) 1998} experiment microphysical, chemical and optical properties of atmospheric particles were measured by several groups. (Bundke et al.). The particle deposition and clearance of the particles in the human respiratory tract was calculated using the ICRP (International Commission on Radiological Protection) deposition and clearance model (ICRP 1994). Particle growth as function of relative humidity outside the body was calculated from measurement data using the model introduced by Bundke et al.. Particle growth inside the body was added using a non-equilibrium particle growth model. As a result of the calculations, time series of the total dry particle mass and -size distribution were obtained for all compartments of the human respiratory tract defined by ICRP 1994. The combined ICRP deposition and clearance model was initialized for different probationers like man, woman, children of different ages and several circumstances like light work, sitting, sleeping etc. Keeping the conditions observed during LACE 98 constant a approximation of the aerosol burdens of the different compartments was calculated up to 4 years of exposure and compared to the results from Snipes et al. for the "Phoenix" and "Philadelphia" aerosol. References: footnotesize{ Bundke, U. et al.,it{Aerosol Optical Properties during the Lindenberg Aerosol Characterization Experiment (LACE 98)} ,10.1029/2000JD000188, JGR, 2002 ICRP,it{Human Respiratory Tract Model for Radiological Protection, Bd. ICRP Publication 66}, Annals of the ICRP, 24,1-3, Elsevier Science, Ocford, 1994 Snipes et al. ,it{The 1994 ICRP66 Human Respiratory Tract Model as a Tool for predicting Lung Burdens from Exposure to Environmental Aerosols}, Appl. Occup. Environ. Hyg., 12, 547-553,1997}

  13. Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds.

    PubMed

    Adler, Gabriela; Koop, Thomas; Haspel, Carynelisa; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven H; Rudich, Yinon

    2013-12-17

    The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges. PMID:24297908

  14. Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds

    PubMed Central

    Adler, Gabriela; Koop, Thomas; Haspel, Carynelisa; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven H.; Rudich, Yinon

    2013-01-01

    The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges. PMID:24297908

  15. Spatially resolved chemical imaging of individual atmospheric particles using nanoscale imaging mass spectrometry: Insights into particle origin and chemistry

    NASA Astrophysics Data System (ADS)

    Ghosal, S.; Weber, P. K.; Laskin, A.

    2014-12-01

    Knowledge of the spatially-resolved composition of atmospheric particles is essential for differentiating between their surface versus bulk chemistry, understanding particle reactivity and the potential environmental impact. We demonstrate the application of nanometer-scale secondary ion mass spectrometry (Cameca NanoSIMS 50 ion probe) for 3D chemical imaging of individual atmospheric particles without any sample pre-treatment, such as the sectioning of particles. Use of NanoSIMS depth profile analysis enables elemental mapping of particles with nanometer spatial resolution over a broad of range of particle sizes. We have used this technique to probe spatially resolved composition of ambient particles collected during a field campaign in Mexico City. Particles collected during this campaign have been extensively characterized in the past using other particle analysis techniques and hence offer a unique opportunity for exploring the utility of depth resolved chemical imaging in ambient particle research. Particles examined in this study include those collected during a pollution episode related to urban waste incineration as well as background particles from the same location prior to the episode. Particles from the pollution episode show substantial intra-particle compositional variability typical of particles resulting from multiple emission sources. In contrast, the background particles have relatively homogeneous compositions with enhanced presence of nitrogen, oxygen and chlorine at the particle surface. The observed surface enhancement of nitrogen and oxygen species is consistent with the presence of surface nitrates resulting from gas-particle heterogeneous interactions and is indicative of atmospheric ageing of the particles. The results presented here illustrate 3D characterization of ambient particles for insights into their chemical history.

  16. Spatially resolved chemical imaging of individual atmospheric particles using nanoscale imaging mass spectrometry: Insighs into particle origin and chemistry

    SciTech Connect

    Ghosal, Sutapa; Weber, Peter K.; Laskin, Alexander

    2014-04-21

    Knowledge of the spatially-resolved composition of atmospheric particles is essential for differentiating between their surface versus bulk chemistry, understanding particle reactivity and the potential environmental impact. We demonstrate the application of nanometer-scale secondary ion mass spectrometry (Cameca NanoSIMS 50 ion probe) for 3D chemical imaging of individual atmospheric particles without any sample pre-treatment, such as the sectioning of particles. Use of NanoSIMS depth profile analysis enables elemental mapping of particles with nanometer spatial resolution over a broad of range of particle sizes. We have used this technique to probe spatially resolved composition of ambient particles collected during a field campaign in Mexico City. Particles collected during this campaign have been extensively characterized in the past using other particle analysis techniques and hence offer a unique opportunity for exploring the utility of depth resolved chemical imaging in ambient particle research. 1 Particles examined in this study include those collected during a pollution episode related to urban waste incineration as well as background particles from the same location prior to the episode. Particles from the pollution episode show substantial intra-particle compositional variability typical of particles resulting from multiple emission sources. In contrast, the background particles have relatively homogeneous compositions with enhanced presence of nitrogen, oxygen and chlorine at the particle surface. The observed surface enhancement of nitrogen and oxygen species is consistent with the presence of surface nitrates resulting from gas-particle heterogeneous interactions and is indicative of atmospheric ageing of the particles. The results presented here illustrate 3D characterization of ambient particles for insights into their chemical history.

  17. Recreational atmospheric pollution episodes: Inhalable metalliferous particles from firework displays

    NASA Astrophysics Data System (ADS)

    Moreno, Teresa; Querol, Xavier; Alastuey, Andrés; Cruz Minguillón, Mari; Pey, Jorge; Rodriguez, Sergio; Vicente Miró, José; Felis, Carles; Gibbons, Wes

    The use of fireworks creates an unusual and distinctive anthropogenic atmospheric pollution event. We report on aerosol samples collected during Las Fallas in Valencia, a 6-day celebration famous for its firework displays, and add comparative data on firework- and bonfire-contaminated atmospheric aerosol samples collected from elsewhere in Spain (Barcelona, L'Alcora, and Borriana) and during the Guy Fawkes celebrations in London. Specific high-profile official firework events during Las Fallas included the afternoon Mascletà and the nightly aerial displays (especially in the climactic final 2 days of the fiesta) and were accompanied by pollution spikes in suspended particles, NO, SO 2, and the creation and dispersal of an aerosol cloud enriched in a range of metallic elements. Notable metal aerosol concentration increases recorded during Las Fallas were potassium (from 500 to 5900 ng m -3), aluminium (as Al 2O 3 from around 600 to 2200 ng m -3), titanium (from 200 to 700 ng m -3), magnesium (from 100 to 500 ng m -3), lead (from 17 to 379 ng m -3), barium (from 39 to 322 ng m -3), strontium (from 3 to 112 ng m -3), copper (from 12 to 71 ng m -3), and antimony (from 1 to 52 ng m -3). Firework-contaminated aerosols of similarly metalliferous composition were also identified at the other monitoring sites, although different sites show variations attributable to other sources such as bonfires and local industry. Unusual levels of the trace elements Ba, Sr and (to a lesser extent) Cu, always in proportions with Ba dominant, along with strongly enhanced K, Pb, and Sb, are identified as being particularly characteristic of firework aerosols. Although firework-related recreational pollution episodes are transient in nature, they are highly concentrated, contribute significantly to total annual metal emissions, and are on average fine enough to be easily inhaled and a health risk to susceptible individuals.

  18. Fragmentation Energetics of Clusters Relevant to Atmospheric New Particle Formation

    SciTech Connect

    Bzdek, Bryan R.; Depalma, Joseph W.; Ridge, Douglas P.; Laskin, Julia; Johnston, Murray V.

    2013-02-27

    The exact mechanisms by which small clusters form and grow in the atmosphere are poorly understood, but this process may significantly impact cloud condensation nuclei number concentrations and global climate. Sulfuric acid is the key chemical component to new particle formation, but basic species such as ammonia are also important. However, few laboratory experiments address the kinetics or thermodynamics of acid and base incorporation into small clusters. This work utilizes a Fourier transform ion cyclotron resonance mass spectrometer equipped with surface-induced dissociation (FTICR-SID) to investigate time- and collision energy-resolved fragmentation of positively charged ammonium bisulfate clusters. Critical energies for dissociation are obtained from Rice-Ramsperger-Kassel-Marcus/Quasi-Equilibrium Theory (RRKM/QET) modeling of the experimental data and are compared to quantum chemical calculations of the thermodynamics of cluster dissociation. Fragmentation of ammonium bisulfate clusters occurs by two pathways: 1) a two-step pathway whereby the cluster sequentially loses ammonia followed by sulfuric acid and 2) a one-step pathway whereby the cluster loses an ammonium bisulfate molecule. Experimental critical energies for loss of an ammonia molecule and loss of an ammonium bisulfate molecule are higher than the thermodynamic values. If cluster growth is considered the reverse of cluster fragmentation, these results require the presence of an activation barrier to describe the incorporation of ammonia into small acidic clusters and suggest that kinetically (i.e. diffusion) limited growth should not be assumed. An important corollary is that models of atmospheric NPF should be revised to consider activation barriers to individual chemical steps along the growth pathway.

  19. Atmospheric Black Carbon: Chemical Bonding and Structural Information of Individual Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Gilles, M. K.; Tivanski, A. V.; Hopkins, R. J.; Marten, B. D.

    2006-12-01

    The formation of aerosols from both natural and anthropogenic sources affects the Earth's temperature and climate by altering the radiative properties of the atmosphere. Aerosols containing black carbon (BC) that are released into the atmosphere from the burning of biomass, natural fires and the combustion of coals, diesel and jet fuels, contribute a large positive component to this radiative forcing, thus causing a heating of the atmosphere. A distinct type of biomass burn aerosol referred to as "tar balls" has recently been reported in the literature and is characterized by a spherical morphology, high carbon content and ability to efficiently scatter and absorb light. At present, very little is known about the exact nature and variation of the range of BC aerosols in the atmosphere with regards to optical, chemical and physical properties. Additionally, the similarity of these aerosols to surrogates used in the laboratory as atmospheric mimics remains unclear. The local chemical bonding, structural ordering and carbon-to-oxygen ratios of a plethora of black carbon standard reference materials (BC SRMs), high molecular mass humic-like substances (HULIS) and atmospheric aerosols from a variety of sources are examined using scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure (NEXAFS) spectroscopy. STXM/NEXAFS enables single aerosol particles of diameter upwards of 100 nm to be studied, which allows the diversity of atmospheric aerosol collected during a variety of field missions to be assessed. We apply a semi-quantitative peak fitting method to the recorded NEXAFS spectral fingerprints allowing comparison of BC SRMs and HULIS to BC aerosol originating from anthropogenic combustion and biomass burning events. This method allows us to distinguish between anthropogenic combustion and biomass burn aerosol using both chemical bonding and structural ordering information. The STXM/NEXAFS technique has also been utilized to study the interfacial region of tar ball particles collected during a biomass burn event. Examination of the carbonyl functional group intensity, as determined from NEXAFS spectra, with particle size has enabled the presence of a thin oxygenated surface layer to be elucidated. Using all of this information, we assess the suitability of the various BC SRMs and HULIS as standards for anthropogenic combustion and biomass burn atmospheric aerosol.

  20. Atmospheric budget of primary biological aerosol particles from fungal spores

    NASA Astrophysics Data System (ADS)

    Heald, Colette L.; Spracklen, Dominick V.

    2009-05-01

    The contribution of primary biological aerosol particles (PBAP) to the global budget of organic aerosol is poorly understood. Concentrations of mannitol, a biotracer for fungal spores, are used here to constrain the first global model (GEOS-Chem) simulation of PBAP from fungi. Emissions are driven by leaf area index and atmospheric water vapor concentrations and are empirically optimized based on the geographical and seasonal variability of observed mannitol concentrations. Optimized global emissions total 28 Tg yr-1, with 25% of that total emitted as fine mode (PM2.5) aerosol. Fungal spores contribute 23% of total primary emissions of organic aerosol, or 7% of the fine-mode source. Annual mean simulated surface concentrations of PBAP over vegetated regions range from 0.1-0.7 μgm-3 (PM2.5) and 0.4-3.0 μgm-3 (PM10), with the highest concentrations in the tropics, where PBAP may be the dominant source of organic aerosol. Further validation is required to reduce the substantial uncertainties on this budget.

  1. Regularized inversion of microphysical atmospheric particle parameters: Theory and application

    NASA Astrophysics Data System (ADS)

    Osterloh, Lukas; Böckmann, Christine; Nicolae, Doina; Nemuc, Anca

    2013-03-01

    Retrieving the distribution of aerosols in the atmosphere via remote sensing techniques is a highly complex task that requires dealing with a wide range of different problems stemming both from Physics and Mathematics. We focus on retrieving this distribution from multi-wavelength lidar data for aerosol ensembles consisting of spherical particles via an iterative regularization technique. The optical efficiencies for spherical scatterers are examined to account for the behavior of the underlying integral equation. The ill-posedness of the problem and the conditioning of the discretized problem are analyzed. Some critical points in the model, like the assumed wavelength-independence of the refractive index and the fixed grid of investigated refractive indices, are studied with regard to their expected impact on the regularized solution. A new Monte-Carlo type method is proposed for retrieval of the refractive index. To validate the results, the developed algorithm is applied to two measurement cases of burning biomass gained from multi-wavelength Raman lidar.

  2. Particle emission from artificial cometary materials

    NASA Technical Reports Server (NTRS)

    Koelzer, Gabriele; Kochan, Hermann; Thiel, Klaus

    1992-01-01

    During KOSI (comet simulation) experiments, mineral-ice mixtures are observed in simulated space conditions. Emission of ice-/dust particles from the sample surface is observed by means of different devices. The particle trajectories are recorded with a video system. In the following analysis we extracted the parameters: particle count rate, spatial distribution of starting points on the sample surface, and elevation angle and particle velocity at distances up to 5 cm from the sample surface. Different kinds of detectors are mounted on a frame in front of the sample to register the emitted particles and to collect their dust residues. By means of these instruments the particle count rates, the particle sizes and the composition of the particles can be correlated. The results are related to the gas flux density and the temperature on the sample surface during the insolation period. The particle emission is interpreted in terms of phenomena on the sample surface, e.g., formation of a dust mantle.

  3. Multiscale Modeling of Metallic Materials Containing Embedded Particles

    NASA Technical Reports Server (NTRS)

    Phillips, Dawn R.; Iesulauro, Erin; Glaessgen, Edward H.

    2004-01-01

    Multiscale modeling at small length scales (10(exp -9) to 10(exp -3) m) is discussed for aluminum matrices with embedded particles. A configuration containing one particle surrounded by about 50 grains and subjected to uniform tension and lateral constraint is considered. The analyses are performed to better understand the effects of material configuration on the initiation and progression of debonding of the particles from the surrounding aluminum matrix. Configurational parameters considered include particle aspect ratio and orientation within the surrounding matrix. Both configurational parameters are shown to have a significant effect on the behavior of the materials as a whole. For elliptical particles with the major axis perpendicular to the direction of loading, a particle with a 1:1 aspect ratio completely debonds from the surrounding matrix at higher loads than particles with higher aspect ratios. As the particle major axis is aligned with the direction of the applied load, increasing amounts of load are required to completely debond the particles.

  4. Charging and coagulation of radioactive and nonradioactive particles in the atmosphere

    NASA Astrophysics Data System (ADS)

    Kim, Yong-ha; Yiacoumi, Sotira; Nenes, Athanasios; Tsouris, Costas

    2016-03-01

    Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual effects of charging and coagulation on the microphysical evolution of atmospheric particles such as radioactive particles. The first approach employs ion balance, charge balance, and a bivariate population balance model (PBM) to comprehensively calculate both charge accumulation and coagulation rates of particles. The second approach involves a much simpler description of charging, and uses a monovariate PBM and subsequent effects of charge on particle coagulation. The third approach is further simplified assuming that particles instantaneously reach their steady-state charge distributions. It is found that compared to the other two approaches, the first approach can accurately predict time-dependent changes in the size and charge distributions of particles over a wide size range covering from the free molecule to continuum regimes. The other two approaches can reliably predict both charge accumulation and coagulation rates for particles larger than about 0.04 micrometers and atmospherically relevant conditions. These approaches are applied to investigate coagulation kinetics of particles accumulating charge in a radioactive neutralizer, the urban atmosphere, and an atmospheric system containing radioactive particles. Limitations of the approaches are discussed.

  5. Charging and coagulation of radioactive and nonradioactive particles in the atmosphere

    SciTech Connect

    Kim, Yong-ha; Yiacoumi, Sotira; Nenes, Athanasios; Tsouris, Costas

    2016-01-01

    Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual effects of charging and coagulation on the microphysical evolution of atmospheric particles such as radioactive particles. The first approach employs ion balance, charge balance, and a bivariate population balance model (PBM) to comprehensively calculate both charge accumulation and coagulation rates of particles. The second approach involves a much simpler description of charging, and uses a monovariate PBM and subsequent effects of charge on particle coagulation. The third approach is further simplified assuming that particles instantaneously reach their steady-state charge distributions. It is found that compared to the other two approaches, the first approach can accurately predict time-dependent changes in the size and charge distributions of particles over a wide size range covering from the free molecule to continuum regimes. The other two approaches can reliably predict both charge accumulation and coagulation rates for particles larger than about 0.04 micrometers and atmospherically relevant conditions. These approaches are applied to investigate coagulation kinetics of particles accumulating charge in a radioactive neutralizer, the urban atmosphere, and an atmospheric system containing radioactive particles. Limitations of the approaches are discussed.

  6. Charging and coagulation of radioactive and nonradioactive particles in the atmosphere

    DOE PAGESBeta

    Kim, Yong-ha; Yiacoumi, Sotira; Nenes, Athanasios; Tsouris, Costas

    2016-01-01

    Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual effects of charging and coagulation on the microphysical evolution of atmospheric particles such as radioactive particles. The first approach employs ion balance, charge balance, and a bivariate population balance model (PBM) to comprehensively calculate both charge accumulation and coagulation rates of particles. The second approach involves a much simpler description of charging, and uses a monovariate PBM and subsequentmore » effects of charge on particle coagulation. The third approach is further simplified assuming that particles instantaneously reach their steady-state charge distributions. It is found that compared to the other two approaches, the first approach can accurately predict time-dependent changes in the size and charge distributions of particles over a wide size range covering from the free molecule to continuum regimes. The other two approaches can reliably predict both charge accumulation and coagulation rates for particles larger than about 0.04 micrometers and atmospherically relevant conditions. These approaches are applied to investigate coagulation kinetics of particles accumulating charge in a radioactive neutralizer, the urban atmosphere, and an atmospheric system containing radioactive particles. Limitations of the approaches are discussed.« less

  7. Quantifying the kinetic limitations of atmospheric gas-to-particle conversion

    NASA Astrophysics Data System (ADS)

    Booth, A.; Murphy, B.; Riipinen, I.; Percival, C.; Topping, D. O.

    2013-12-01

    Atmospheric aerosol particles, from anthropogenic and biogenic sources, remain a major uncertainty in the Earth system: they impact the climate by directly scattering and absorbing solar radiation, as well as regulating the properties of clouds. On regional scales, aerosols are among the main pollutants deteriorating air quality, their impacts on both poorly quantified. Reducing these uncertainties requires accurate knowledge on the composition, concentrations and size distributions of these particles as they reside in the atmosphere. Unfortunately, there are currently huge uncertainties in many fundamental parameters that are required to predict their environmental impacts. This is largely down to the fact that a significant fraction of atmospheric aerosol particles are comprised of organic material (20-90% of particle mass), containing potentially thousands of compounds with largely uncertain properties It is becoming increasingly evident that aerosols exist as metastable amorphous states, rather than simple liquid/solid mixtures. Empirical evidence suggests that particles can form glass like substances. As the glass transition temperature is approached, an increase in viscosity leads to a reduced rate of molecular diffusion and an arrested non-equilibrium structure. Partitioning between the gas and condensed phase is kinetically limited in such amorphous states. Traditional organic aerosol models do not account for this, they assume that 1) the aerosol phase is a well-mixed non-viscous liquid; 2) the aerosol phase instantaneously equilibrates with the gas phase constituents. This adds significant uncertainty to predictions of gas/particle mass transfer as mixing timescales are ultimately governed by the diffusion coefficients of the aerosol constituents in the aerosol, which, on the other hand, are connected to the viscosity of the particulate matter. For typical aerosol sizes, the characteristic time for mixing could increase from a few milliseconds to hours or even days. In this study, we present direct laboratory determination of viscosity/diffusing of atmospherically relevant species along with an evaluation of composition dependent predictive techniques. Output from highly detailed chemical mechanisms are used to probe potential sensitivities of these kinetic limitations and sensitivities to our predictive capability.

  8. Measuring Mass-Based Hygroscopicity of Atmospheric Particles through in Situ Imaging.

    PubMed

    Piens, Dominique S; Kelly, Stephen T; Harder, Tristan H; Petters, Markus D; O'Brien, Rachel E; Wang, Bingbing; Teske, Ken; Dowell, Pat; Laskin, Alexander; Gilles, Mary K

    2016-05-17

    Quantifying how atmospheric particles interact with water vapor is critical for understanding the effects of aerosols on climate. We present a novel method to measure the mass-based hygroscopicity of particles while characterizing their elemental and carbon functional group compositions. Since mass-based hygroscopicity is insensitive to particle geometry, it is advantageous for probing the hygroscopic behavior of atmospheric particles, which can have irregular morphologies. Combining scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), scanning transmission X-ray microscopy (STXM) analysis, and in situ STXM humidification experiments, this method was validated using laboratory-generated, atmospherically relevant particles. Then, the hygroscopicity and elemental composition of 15 complex atmospheric particles were analyzed by leveraging quantification of C, N, and O from STXM, and complementary elemental quantification from SEM/EDX. We found three types of hygroscopic responses, and correlated high hygroscopicity with Na and Cl content. The mixing state of 158 other particles from the sample broadly agreed with those of the humidified particles, indicating the potential to infer atmospheric hygroscopic behavior from a selected subset of particles. These methods offer unique quantitative capabilities to characterize and correlate the hygroscopicity and chemistry of individual submicrometer atmospheric particles. PMID:27088454

  9. Size matters in the water uptake and hygroscopic growth of atmospherically relevant multicomponent aerosol particles.

    PubMed

    Laskina, Olga; Morris, Holly S; Grandquist, Joshua R; Qin, Zhen; Stone, Elizabeth A; Tivanski, Alexei V; Grassian, Vicki H

    2015-05-14

    Understanding the interactions of water with atmospheric aerosols is crucial for determining the size, physical state, reactivity, and climate impacts of this important component of the Earth's atmosphere. Here we show that water uptake and hygroscopic growth of multicomponent, atmospherically relevant particles can be size dependent when comparing 100 nm versus ca. 6 μm sized particles. It was determined that particles composed of ammonium sulfate with succinic acid and of a mixture of chlorides typical of the marine environment show size-dependent hygroscopic behavior. Microscopic analysis of the distribution of components within the aerosol particles show that the size dependence is due to differences in the mixing state, that is, whether particles are homogeneously mixed or phase separated, for different sized particles. This morphology-dependent hygroscopicity has consequences for heterogeneous atmospheric chemistry as well as aerosol interactions with electromagnetic radiation and clouds. PMID:25521409

  10. Atmospheric giant particles (iberulites) from African desert soils and human health

    NASA Astrophysics Data System (ADS)

    Párraga, Jesús; Delgado, Gabriel; Bech, Jaume; Martín-García, Juan Manuel; Delgado, Rafael

    2013-04-01

    Earth is twice as dusty as in 19th century. The amount of soil dust in the Earth's atmosphere has doubled over the last century. The circum-Mediterranean area has one of the highest dust accretion rates in the world. The larger deserts (Sahara, Gobi, Badai Jaran, etc.) are the primary sources of mobilized desert-dust top soil that move great distances through the troposphere each year. Erosion, atmospheric transport, and dust-sized soil particles deposition to earth's surface are important process in aeolian environments. Atmospheric dust is associated to global climate change. Iberulites are giant microspherulitic particles (87.9 × 27.6 µm) rounded and reddish, generated in the atmosphere (troposphere) by coalescence of smaller particles, finally falling to the earth's surface. The name comes from the Iberian Peninsula where they were discovered. An iberulite is a co-association with axial geometry, consisting of well-defined mineral grains, together with non-crystalline compounds, structured around a coarse-grained core with a smectite rind, only one vortex and pinkish color formed in the troposphere by complex aerosol-water-gas interactions. Sedimentable dust ("dry deposition") in the city of Granada (Spain) for 17 African dust intrusion events occurring in the summer months of 2010 has been studied. In all samples were detected (SEM, stereomicroscope) iberulites. Total dust and the iberulites are composed mainly by mineral particles of different nature (XRD and SEM-EDX) and size less than 10µm (laser technique), implying dangerousness by inhalation. In the total dust the dominant mineral is dolomite [CaMg(CO3)2], abundant in the surroundings of the city; in the iberulites dominates the quartz (SiO2), which indicates Saharan origin. The iberulites and the total dust are associated with metals (ICP-MS) that have a capacity to transport electrons with a high toxic potential in the body. The concentration of Cu and Pb in total dust were 5 and 2.5 times higher than the soil background values of Granada province. In the iberulites we have detected (SEM-EDX) biological material (bacteria, diatoms, nanoplankton, etc.) which allows to emit a hypothesis about their role as vectors (atmospherical "shuttles") for alloctonous diseases. Recently has been observed the role of Saharan dust in the relationship between particulate matter and short-term daily mortality among the elderly in Madrid (Spain).

  11. Comparing the Treatment of Spherical and Fractal Particles in Titan’s Atmosphere using CARMA

    NASA Astrophysics Data System (ADS)

    Lanzano, Alexander; Barth, Erika

    2015-11-01

    The nature of Titan’s optically thick haze is of great interest in the study of its atmosphere. In an attempt to further understand the particle distribution and radiative properties of this haze we applied the Community Aerosol and Radiation Model for Atmospheres (CARMA), originally designed for Earth, to simulate the microphysical and radiative transfer properties of Titan’s atmosphere. In the past, the model treated the haze particles as spheres, however, it is more accurate to treat the haze particles as fractals (Lavvas et al. 2010). We first simulated spherical particles to verify the model’s consistency with past studies (i.e. Toon et al. 1992). We then ran simulations considering fractal haze particles. In both instances we considered a 600km atmosphere with a production zone centered at 300km from the surface. These particles, initially 0.0013 µm in radius, are then subject to vertical transport and coagulation processes affecting the size, number, and distribution of the particles. Our results for both cases show that for wavelengths of 550nm the optical depth and extinction of the atmosphere rapidly decreases above 400km, however, there is a greater concentration of fractal particles at altitudes above 400km than spherical particles by at least two orders of magnitude. Initial results indicate that above 400km there were approximately 2x105 fractal particles/cm3 whereas there were only at most 1x103 spherical particles/cm3 corresponding with a greater cumulative optical depth of Titan’s atmosphere for fractal particles than spherical particles. The full effects of these results on the cumulative optical depth of the atmosphere are still being explored.This work was funded by the NASA Outer Planets research program.

  12. PD-FiTE - an efficient method for calculating gas / liquid equilibria in atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Topping, D.; Lowe, D.; McFiggans, G.; Barley, M.

    2009-04-01

    Assessing the impact of atmospheric aerosol particles on the environment requires adequate representation of appropriate key processes within large scale models. In the absence of primary particulate material, interactions between the atmospheric gaseous components and particles means that the chemical nature of the particles is largely determined by the availability of condensable gaseous material, such as sulphuric and nitric acids, and by the ambient environmental conditions. Gas to particle mass transfer of semi-volatile components,driven by a difference in equilibrium and actual partial pressures above an aerosol particle, is an important factor in determining the evolving chemical composition of the particle and is necessary for predicting aerosol loading and composition. The design of an appropriate framework required for parameterizations of key variables is challenging. These thermodynamic frameworks are often numerically very complex, resulting in significant computational expense. Three dimensional chemical and aerosol transport models demand that computational expense be kept at a minimum,resulting in a trade-off between accuracy and efficiency. To calculate the equilibrium vapour pressure above a solution requires treatment of solution nonideality. This is manifest through activity coefficients of components pertinent to each condensing specie. However, activity coefficients are complex functions of the solution composition. Parameterisation of activity coefficients provides the main focus of this work largely because reducing the numerical complexity whilst retaining a good level of accuracy is very challenging. The approach presented here, the hybrid Partial Derivative Fitted Taylor Expansion (PDFiTE) (Topping et al 2008), builds on previously reported work, with an aim to derive parameters for an accurate and computationally efficient framework through coupling with a complex thermodynamic model. Such a reduction in complexity is important as it is necessary to further include an as yet unspecified number of condensing organic species, thus increasing the computational burden of any existing framework. Using this coupled approach we derive optimised model parameters describing the interaction between different chemical components, resulting in a significant increase in computational performance, in some cases giving a four fold decrease in the required number of floating point operations, whilst remaining accurate. Overall, comparisons with the most accurate inorganic activity coefficient model available (Clegg et al1998) and an existing parameterisation (MTEM) (Zaveri et al 2005) indicate that the methodology behind PD-FiTE gives an increase in accuracy for calculating the vapour pressure of all condensing gases when averaged over the parameterisation space of the system H+-NH4+-Na+-SO42--HSO4--NO3--Cl-. Following this, the reduced parameterisation is coupled into a combined chemistry / microphysical aerosol model in a dynamical simulation of aerosol composition. This demonstrates the robustness of our model and also demonstrates the implications of its use. As a simple test case we investigate the response of a typical marine aerosol passing through a polluted environment. This shows the robustness of PD-FiTE and illustrates its usefulness in capturing the fine details of important phenomena such as the outgassing of HCl in response to HNO3 uptake by sea-salt particles. Further, since semi-volatile organic compounds are ubiquitous and secondary organic aerosol is thought to be a major fraction of submicron aerosol mass, the inclusion of organic compounds into the framework will be reported. References: Clegg, S. L., et al. (1992), Thermodynamics of Multicomponent, Miscible, Ionic-Solutions .2. Mixtures Including Unsymmetrical Electrolytes,Journal of Physical Chemistry, 96, 9470-9479. Topping, D.O. et al (2008). An Efficient and Accurate Scheme for the Partitioning of Atmospheric Semi-Volatile Components - 1 Inorganic Compounds. Submitted to Journal of Geophysical Research. Zaveri, R. A., et al. (2005), A new method for multicomponent activity coefficients of electrolytes in aqueous atmospheric aerosols, Journal of Geophysical Research-Atmospheres, 110.

  13. Oxidation products of biogenic emissions contribute to nucleation of atmospheric particles.

    PubMed

    Riccobono, Francesco; Schobesberger, Siegfried; Scott, Catherine E; Dommen, Josef; Ortega, Ismael K; Rondo, Linda; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Downard, Andrew; Dunne, Eimear M; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hansel, Armin; Junninen, Heikki; Kajos, Maija; Keskinen, Helmi; Kupc, Agnieszka; Kürten, Andreas; Kvashin, Alexander N; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Mathot, Serge; Nieminen, Tuomo; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud P; Santos, Filipe D; Schallhart, Simon; Seinfeld, John H; Sipilä, Mikko; Spracklen, Dominick V; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjö; Vrtala, Aron; Wagner, Paul E; Weingartner, Ernest; Wex, Heike; Wimmer, Daniela; Carslaw, Kenneth S; Curtius, Joachim; Donahue, Neil M; Kirkby, Jasper; Kulmala, Markku; Worsnop, Douglas R; Baltensperger, Urs

    2014-05-16

    Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations. PMID:24833386

  14. Direct night-time ejection of particle-phase reduced biogenic sulfur compounds from the ocean to the atmosphere.

    PubMed

    Gaston, Cassandra J; Furutani, Hiroshi; Guazzotti, Sergio A; Coffee, Keith R; Jung, Jinyoung; Uematsu, Mitsuo; Prather, Kimberly A

    2015-04-21

    The influence of oceanic biological activity on sea spray aerosol composition, clouds, and climate remains poorly understood. The emission of organic material and gaseous dimethyl sulfide (DMS) from the ocean represents well-documented biogenic processes that influence particle chemistry in marine environments. However, the direct emission of particle-phase biogenic sulfur from the ocean remains largely unexplored. Here we present measurements of ocean-derived particles containing reduced sulfur, detected as elemental sulfur ions (e.g., (32)S(+), (64)S2(+)), in seven different marine environments using real-time, single particle mass spectrometry; these particles have not been detected outside of the marine environment. These reduced sulfur compounds were associated with primary marine particle types and wind speeds typically between 5 and 10 m/s suggesting that these particles themselves are a primary emission. In studies with measurements of seawater properties, chlorophyll-a and atmospheric DMS concentrations were typically elevated in these same locations suggesting a biogenic source for these sulfur-containing particles. Interestingly, these sulfur-containing particles only appeared at night, likely due to rapid photochemical destruction during the daytime, and comprised up to ∼67% of the aerosol number fraction, particularly in the supermicrometer size range. These sulfur-containing particles were detected along the California coast, across the Pacific Ocean, and in the southern Indian Ocean suggesting that these particles represent a globally significant biogenic contribution to the marine aerosol burden. PMID:25835033

  15. Status and potential of atmospheric plasma processing of materials

    SciTech Connect

    Pappas, Daphne

    2011-03-15

    This paper is a review of the current status and potential of atmospheric plasma technology for materials processing. The main focus is the recent developments in the area of dielectric barrier discharges with emphasis in the functionalization of polymers, deposition of organic and inorganic coatings, and plasma processing of biomaterials. A brief overview of both the equipment being used and the physicochemical reactions occurring in the gas phase is also presented. Atmospheric plasma technology offers major industrial, economic, and environmental advantages over other conventional processing methods. At the same time there is also tremendous potential for future research and applications involving both the industrial and academic world.

  16. Particle size effect for metal pollution analysis of atmospherically deposited dust

    NASA Astrophysics Data System (ADS)

    Al-Rajhi, M. A.; Al-Shayeb, S. M.; Seaward, M. R. D.; Edwards, H. G. M.

    The metallic compositions of 231 atmospherically deposited dust samples obtained from widely-differing environments in Riyadh city, Saudi Arabia, have been investigated in relation to the particle size distributions. Sample data are presented which show that particle size classification is very important when analysing dust samples for atmospheric metal pollution studies. By cross-correlation and comparison, it was found that the best way to express the results of the metal concentration trend was as an average of particle ratios. Correlations between the six metals studied, namely Pb, Cr, Ni, Cu, Zn and Li, were found for every particle size (eight categories) and reveal that the metal concentrations increased as the particle size decreased. On the basis of this work, it is strongly recommended that future international standards for metal pollutants in atmospherically deposited dusts should be based on particle size fractions.

  17. Generation of nano roughness on fibrous materials by atmospheric plasma

    NASA Astrophysics Data System (ADS)

    Kulyk, I.; Scapinello, M.; Stefan, M.

    2012-12-01

    Atmospheric plasma technology finds novel applications in textile industry. It eliminates the usage of water and of hazard liquid chemicals, making production much more eco-friendly and economically convenient. Due to chemical effects of atmospheric plasma, it permits to optimize dyeing and laminating affinity of fabrics, as well as anti-microbial treatments. Other important applications such as increase of mechanical resistance of fiber sleeves and of yarns, anti-pilling properties of fabrics and anti-shrinking property of wool fabrics were studied in this work. These results could be attributed to the generation of nano roughness on fibers surface by atmospheric plasma. Nano roughness generation is extensively studied at different conditions. Alternative explanations for the important practical results on textile materials and discussed.

  18. Large area nuclear particle detectors using ET materials

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The purpose of this SBIR Phase 1 feasibility effort was to demonstrate the usefulness of Quantex electron-trapping (ET) materials for spatial detection of nuclear particles over large areas. This demonstration entailed evaluating the prompt visible scintillation as nuclear particles impinged on films of ET materials, and subsequently detecting the nuclear particle impingement information pattern stored in the ET material, by means of the visible-wavelength luminescence produced by near-infrared interrogation. Readily useful levels of scintillation and luminescence outputs are demonstrated.

  19. Estimates of atmospheric deposition of submicron particle-associated combustion derived organic contaminants to Chesapeake Bay

    SciTech Connect

    Leister, D.L.; Baker, J.E.

    1994-12-31

    Once emitted into the atmosphere, combustion derived organic contaminants partition between gaseous and particle phases. In order to estimate the wet and dry removal of contaminants from the atmospheric to surface waters, it is necessary to measure gaseous and particle-associated contaminant concentrations because the deposition mechanisms of each phase differ. The authors estimate dry and wet depositional fluxes of polycyclic aromatic hydrocarbons (PAH) as a function of large and small particles to provide insight to the contribution of small particles to the overall atmospheric flux of organic contaminants to surface waters. Utilizing data gathered from concurrent measurements of 10 PAHs associated with particles in rain an in the atmosphere adjacent to Chesapeake Bay, and from PAH particle-size distribution data recently collected at Egbert, Ontario, calculated non-crustal PAH dry particle fluxes range from 40 to as high as 160 ng/m{sup 2}/month. Despite the lower estimated deposition velocity for noncrustal particles relative to that for partially crustal particles, non-crustal PAH particle fluxes are about a factor of five larger than those calculated for particles with a partial crustal component. Monthly wet fluxes of submicron particles range from 12 to 260 ng/m{sup 2}/month and in contrast to dry periods, are similar to those for large particles. Their calculations suggest that the atmospheric loading of submicron particle associated PAHs on an annual basis during dry and wet periods are significant due to the high concentrations of contaminants in this size range in both air and rain.

  20. Doped luminescent materials and particle discrimination using same

    DOEpatents

    Doty, F. Patrick; Allendorf, Mark D; Feng, Patrick L

    2014-10-07

    Doped luminescent materials are provided for converting excited triplet states to radiative hybrid states. The doped materials may be used to conduct pulse shape discrimination (PSD) using luminescence generated by harvested excited triplet states. The doped materials may also be used to detect particles using spectral shape discrimination (SSD).

  1. Particle sizes and composition of Mars atmospheric dust based upon Viking and Mariner 9 observations

    NASA Technical Reports Server (NTRS)

    Clancy, R. T.; Lee, S. W.; Gladstone, G. R.

    1993-01-01

    Mars atmospheric dust can play an important role in the thermal structure of the Mars atmosphere during periods of high dust loading. However, the radiative properties of Mars atmospheric dust remain uncertain due to uncertain definitions of the dust composition and size distribution. The analysis by Toon et al., of Mariner 9 IRIS spectra during the 1971-1972 global dust storm indicated a reasonable match between the modeled 9-micron absorption of montmorillinite and the observed 9-micron absorption. Toon et al. also determined that an effective (cross-section weighted) mean radius of 2.5 microns (R(sub mode) = 0.4 microns) provided a consistent fit of montmorillinite to the IRIS dust spectra at 9 microns. Pollack et al. analyzed Viking lander observations of atmospheric extinction and scattering at visible-near IR wavelengths (0.5-1.0 microns), and obtained consistency with the Toon et al. dust size distribution when the effects of nonspherical particle shapes were included. An additional, minor (1 percent) component of visible-ultraviolet absorbing material was required to model the derived visible (0.86) and ultraviolet (0.4-0.6) single-scattering albedos of the dust, since montmorillinite does not absorb sufficiently in this wavelength region. A combined analysis of the Viking IRTM and Mariner 9 observations was conducted to reassess the model of Mars atmospheric ultraviolet-to-infrared measurements of dust absorption and scattering. The optical constants for palagonite are incorporated in a doubling-adding radiative transfer model of the Mars atmosphere to simulate Mariner 9 IRIS spectra as well as the Viking IRTM IR band observations. Visible and ultraviolet single-scattering albedos based on the Hansen and Travis Mie scattering code were also derived. A tentative conclusion is that smaller dust particles (R(sub mode) = 0.15 microns, cross-section weighted mean R = 1.2 microns) composed of palagonite provide a much improved fit to the Mariner 9 IRIS spectra; agreement with the observed ratio of visible-to-infrared extinction opacities; and ultraviolet and visible single-scattering albedos comparable to their observed values.

  2. Detection and characterization of biological and other organic-carbon aerosol particles in atmosphere using fluorescence

    NASA Astrophysics Data System (ADS)

    Pan, Yong-Le

    2015-01-01

    This paper offers a brief review on the detection and characterization of biological and other organic-carbon (OC) aerosol particles in atmosphere using laser-induced-fluorescence (LIF) signatures. It focuses on single individual particles or aggregates in the micron and super-micron size range when they are successively drawn through the interrogation volume of a point detection system. Related technologies for these systems that have been developed in last two decades are also discussed. These results should provide a complementary view for studying atmospheric aerosol particles, particularly bioaerosol and OC aerosol particles from other analytical technologies.

  3. Concentrations of PAHs in atmospheric particles (PM-10) and roadside soil particles collected in Kuala Lumpur, Malaysia

    NASA Astrophysics Data System (ADS)

    Omar, Nasr Yousef M. J.; Abas, M. Radzi Bin; Ketuly, Kamal Aziz; Tahir, Norhayati Mohd

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particles and roadside soil particles were measured at eight locations in the city center and the suburb of Kuala Lumpur, Malaysia. Atmospheric particles were collected using high-volume PM-10 sampler on glass fiber filters over 24 h average sampling period. Both types of samples were extracted with dichloromethane by ultrasonic agitation. The extracts were then fractionated on an alumina-silica column and the aromatic fraction was subjected to gas chromatography-mass spectrometric (GC-MS) analysis. Total PAH concentrations in the atmospheric particles and roadside soil particles were found to be 6.28±4.35 ng m -3 and 0.22±0.11 μg g -1, respectively. Benzo[ g, h, i]perylene and coronene were found to be the most abundant PAHs in airborne particles at all locations. The most abundant PAHs in the roadside soil particles were fluoranthene, pyrene and phenanthrene.

  4. [Atmospheric particle formation events in Nanjing during summer 2010].

    PubMed

    Wang, Hong-Lei; Zhu, Bin; Shen, Li-Juan; Kang, Han-Qing; Diao, Yi-Wei

    2012-03-01

    Feature of aerosol particle number concentration, condition and impact factor of new particle formation (NPF) were investigated in Nanjing during summer. In this study, aerosol particle number concentration and gaseous pollutants (O3, SO2 and NO2) measurements were carried out by Wide-Range Particle Spectrometer (WPS) and Differential Optical Absorption Spectroscopy (DOAS) in July 2010. Combining with observations from Automatic Weather Station and Backward Trajectory Simulation, the condition and impact factor of NPF were discussed. Results showed that the averaged 10-500 nm particle number concentration was 1.7 x 10(4) cm(-3), similar to some typical observation values in North American and Europe; the 10-25 nm particle number concentration accounted for 25% of the total number concentration. Six NPF events occurred during observation. We analyzed that stable wind speed and direction, strong solar radiation promoted the NPF. The humidity during NPF event varied from 50% to 70%. Results indicated that clean ocean air mass brought from easterly and southerly wind promoted the NPF by Backward Trajectory Model Simulation. During the NPF event, the 10 - 25 nm particle number concentration positively correlated with the concentration of SO2, and negatively correlated with O3, whereas poorly correlated with NO2. PMID:22624358

  5. Secondary Cosmic Ray Particles Due to GCR Interactions in the Earth's Atmosphere

    SciTech Connect

    Battistoni, G.; Cerutti, F.; Fasso, A.; Ferrari, A.; Garzelli, M.V.; Lantz, M.; Muraro, S. Pinsky, L.S.; Ranft, J.; Roesler, S.; Sala, P.R.; ,

    2009-06-16

    Primary GCR interact with the Earth's atmosphere originating atmospheric showers, thus giving rise to fluxes of secondary particles in the atmosphere. Electromagnetic and hadronic interactions interplay in the production of these particles, whose detection is performed by means of complementary techniques in different energy ranges and at different depths in the atmosphere, down to the Earth's surface. Monte Carlo codes are essential calculation tools which can describe the complexity of the physics of these phenomena, thus allowing the analysis of experimental data. However, these codes are affected by important uncertainties, concerning, in particular, hadronic physics at high energy. In this paper we shall report some results concerning inclusive particle fluxes and atmospheric shower properties as obtained using the FLUKA transport and interaction code. Some emphasis will also be given to the validation of the physics models of FLUKA involved in these calculations.

  6. Control Experiment of Positively Charged Fine Particles at the Atmospheric Pressure

    SciTech Connect

    Yokota, Toshiaki; Ando, Ayumi; Sato, Noriyoshi

    2005-10-31

    It is already reported that the negatively charged fine particle flow was controlled by application of external electric field. The control of positively charged fine particles was examined in this experiment.The fine particles are able to take charges in the air under the atmospheric pressure by irradiation of UV light. The control of the positively charged fine particles has been attempted by the external electric field applied the negative potential. The fine particles for experiments are volcanic ashes, nylon 16, glass, and ice. Experiment was performed in the T-shaped glass chamber under the atmospheric pressure. The halogen lamp (500 W) was used to exit the electrons from particles by photo-emission. The ring and disk electrodes to control the positively charged particles were set at the bottom of chamber. The parallel electrodes were set at the middle of chamber and horizontal static electric fields (E = 0 {approx} 210 V/cm) were created in order to estimate the charge of fine particles. The charges of particle were estimated by the deflection of particle trajectory in the static electric fields and particle velocity. The estimated charges were 104e {approx} 5x106e and 103e {approx} 105e for volcanic ashes and nylon 16, respectively. When positively charged particles were introduced into collecting electrodes, the fine particles are collected in the electrodes. The result of control of positively charged fine particles is shown in this conference.

  7. Use of Atmospheric Glow Discharge Plasma to Modify Spaceport Materials

    NASA Technical Reports Server (NTRS)

    Trigwell, S.; Shuerger, A. C.; Buhler, C. R.; Calle, C. J.

    2006-01-01

    Numerous materials used in spaceport operations require stringent evaluation before they can be utilized. It is critical for insulative polymeric materials that any surface charge be dissipated as rapidly as possible to avoid Electrostatic Discharges (ESD) that could present a danger. All materials must pass the Kennedy Space Center (KSC) standard electrostatic test [1]; however several materials that are considered favorable for Space Shuttle and International Space Station use have failed. Moreover, to minimize contamination of Mars spacecraft, spacecraft are assembled under cleanroom conditions and specific cleaning and sterilizing procedures are required for all materials. However, surface characteristics of these materials may allow microbes to survive by protecting them from sterilization and cleaning techniques. In this study, an Atmospheric Pressure Glow Discharge Plasma (APGD) [2] was used to modify the surface of several materials. This allowed the materials surface to be modified in terms of hydrophilicity, roughness, and conductivity without affecting the bulk properties. The objectives of this study were to alter the surface properties of polymers for improved electrostatic dissipation characteristics, and to determine whether the consequent surface modification on spaceport materials enhanced or diminished microbial survival.

  8. Process for application of powder particles to filamentary materials

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M. (Inventor); Snoha, John J. (Inventor); Marchello, Joseph M. (Inventor)

    1991-01-01

    This invention is a process for the uniform application of polymer powder particles to a filamentary material in a continuous manner to form a uniform composite prepreg material. A tow of the filamentary material is fed under carefully controlled tension into a spreading unit, where it is spread pneumatically into an even band. The spread filamentary tow is then coated with polymer particles from a fluidized bed, after which the coated filamentary tow is fused before take-up on a package for subsequent utilization. This process produces a composite prepreg uniformly without imposing severe stress on the filamentary material, and without requiring long, high temperature residence times for the polymer.

  9. Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds

    NASA Astrophysics Data System (ADS)

    Rudich, Yinon; Adler, Gabriela; Koop, Thomas; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven; Haspel, Carynelisa

    2014-05-01

    In cold high altitude cirrus clouds and anvils of high convective clouds in the tropics and mid-latitudes, ice partciles that are exposed to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. In this talk we will describe experiements that simulate the atmospheric freeze-drying cycle of aerosols. We find that aerosols with high organic content can form highly porous particles (HPA) with a larger diameter and a lower density than the initial homogenous aerosol following ice subliation. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure follwoing ice sublimation. We find that the highly porous aerosol scatter solar light less efficiently than non-porous aerosol particles. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges.

  10. Measurements of hygroscopicity and volatility of atmospheric ultrafine particles during ultrafine particle formation events at urban, industrial, and coastal sites.

    PubMed

    Park, Kihong; Kim, Jae-Seok; Park, Seung Ho

    2009-09-01

    The tandem differential mobility analyzer (TDMA) technique was applied to determine the hygroscopicity and volatility of atmospheric ultrafine particles in three sites of urban Gwangju, industrial Yeosu, and coastal Taean in South Korea. A database for the hygroscopicity and volatility of the known compositions and sizes of the laboratory-generated particles wasfirst constructed for comparison with the measured properties of atmospheric ultrafine particles. Distinct differences in hygroscopicity and volatility of atmospheric ultrafine particles werefound between a "photochemical event" and a "combustion event" as well as among different sites. At the Gwangju site, ultrafine particles in the "photochemical event" were determined to be more hygroscopic (growth factor (GF) = 1.05-1.33) than those in the "combustion event" (GF = 1.02-1.12), but their hygroscopicity was not as high as pure ammonium sulfate or sulfuric acid particles in the laboratory-generated database, suggesting they were internally mixed with less soluble species. Ultrafine particles in the "photochemical event" at the Yeosu site, having a variety of SO2, CO, and VOC emission sources, were more hygroscopic (GF = 1.34-1.60) and had a higher amount of volatile species (47-75%)than those observed at the Gwangju site. Ultrafine particle concentration at the Taean site increased during daylight hours with low tide, having a higher GF (1.34-1.80) than the Gwangju site and a lower amount of volatile species (17-34%) than the Yeosu site. Occasionally ultrafine particles were externally mixed according to their hygroscopicity and volatility, and TEM/EDS data showed that each type of particle had a distinct morphology and elemental composition. PMID:19764239

  11. An alpha particle experiment for chemical analysis of the Martian surface and atmosphere.

    NASA Technical Reports Server (NTRS)

    Economou, T. E.; Turkevich, A. L.; Patterson, J. H.

    1973-01-01

    An alpha particle experiment similar to the one performed successfully on the Surveyor lunar missions is described. It is designed to provide a chemical analysis of the Martian surface and atmosphere. Analyses of rocks of known and unknown compositions have been made under simulated Martian conditions. The accuracies attained are generally comparable to those of the Surveyor lunar analyses. Improvements have been achieved in determining carbon and oxygen, so that a few per cent of water or carbonates in rocks can be detected. Some aspects of the integration of such an experiment with the spacecraft, a possible mission profile, and some other problems associated with a soft-landing mission to Mars are discussed. The importance of such a chemical analysis experiment in answering current questions about the nature and history of Martian surface material and its suitability for life processes is presented.

  12. Superparamagnetic Fe3O4 particles formed by oxidation of pyrite heated in an anoxic atmosphere

    USGS Publications Warehouse

    Thorpe, A.N.; Senftle, F.E.; Talley, R.; Hetherington, S.; Dulong, F.

    1990-01-01

    As a follow-up to previous gas analysis experiments in which pyrite was heated to 681 K in an anoxic (oxygen starved) atmosphere, the first oxidation product, FeSO4, was studied as a bulk material. No decomposition of FeSO4 to Fe3O4 was observed in the temperature range studied. The lack of decomposition of bulk FeSO4 to Fe3O4 suggests that FeS2 oxidizes directly to Fe3O4, or that FeSO4, FeS2 and O2 react together to form Fe3O4. Magnetic susceptibility and magnetization measurements, along with magnetic hysteresis curves, show that small particles of Fe3O4 form on the pyrite surface, rather than a continuous layer of bulk Fe3O4. A working model describing the oxidation steps is presented. ?? 1990.

  13. Erosion tests of materials by energetic particle beams

    SciTech Connect

    Schechter, D.E.; Tsai, C.C.; Sluss, F.; Becraft, W.R.; Hoffman, D.J.

    1985-01-01

    The internal components of magnetic fusion devices must withstand erosion from and high heat flux of energetic plasma particles. The selection of materials for the construction of these components is important to minimize contamination of the plasma. In order to study various materials' comparative resistance to erosion by energetic particles and their ability to withstand high heat flux, water-cooled copper swirl tubes coated or armored with various materials were subjected to bombardment by hydrogen and helium particle beams. Materials tested were graphite, titanium carbide (TiC), chromium, nickel, copper, silver, gold, and aluminum. Details of the experimental arrangement and methods of application or attachment of the materials to the copper swirl tubes are presented. Results including survivability and mass losses are discussed.

  14. A Plasma Window for Transmission of Radiation and Particle Beams from Vacuum to Atmosphere for Various Applications

    NASA Astrophysics Data System (ADS)

    Hershcovitch, Ady

    1997-11-01

    Many industrial and scientific processes like electron beam melting and welding, material modification by ion implantation, dry etching, and micro-fabrication, as well as generation of synchrotron radiation are performed almost exclusively in vacuum nowadays, since the electron and ion guns and their extractors must be kept at a reasonably high vacuum. Consequently, there are numerous drawbacks, among which are low production rates due to required pumping time, limits the vacuum volume sets on the size of target objects. In a small number of applications like non-vacuum electron beam welding, and various processes involving UV and x-ray radiation, thin vacuum walls or long stages of differential pumping are used. But, the resultant degradations of particle and radiation beams severely limit those applications. A novel apparatus, which utilized a short plasma arc, was successfully used to maintain a pressure of 7.6 x exp(-6) Torr in a vacuum chamber with a 2.36mm aperture to atmosphere, i.e., a plasma was successfully used to "plug" a hole to atmosphere while maintaining a reasonably high vacuum in the chamber. Successful transmission of charged particle beams from a vacuum through the plasma to atmosphere was accomplished. More details can be found in A. Hershcovitch, J. Appl. Physics 78, p. 5283 (1995). In addition to sustaining a vacuum atmosphere interface, the plasma has very strong lensing effect on charged particles. The plasma current generates an azimuthal magnetic field which exerts a radial Lorentz on charged particles moving parallel to the current channel. With proper orientation of the current direction, the Lorentz force is radially inward. This feature can be used to focus in beams to a very small spot size, and to overcome beam dispersion due to scattering by atmospheric atoms and molecules. Relatively hot plasma at the atmosphere boundary rarefies the atmospheric gases to further enhance particle beam propagation to the materials to target. Recent experimental results, with a plasma window coupled to a venturi, show a factor of three further enhancement in vacuum-atmosphere separation.

  15. Scanning Electron Microanalysis and Analytical Challenges of Mapping Elements in Urban Atmospheric Particles

    EPA Science Inventory

    Elemental mapping with energy-dispersive X-ray spectroscopy (EDX) associated with scanning electron microscopy is highly useful for studying internally mixed atmospheric particles. Presented is a study of individual particles from urban airsheds and the analytical challenges in q...

  16. UNDERSTANDING AND REDUCING THE UNCERTAINTY ASSOCIATED WITH THE EFFECT OF ATMOSPHERIC PARTICLES ON CLOUDS AND CLIMATE

    EPA Science Inventory

    I predict that human-generated particles have modified clouds and cooled climate, somewhat masking the effect of greenhouse gases and that these particles have also modified the amount of sunlight reaching the ground, changing the thermodynamic cycles in the atmosphere. Wi...

  17. Materials processing with atmospheric-pressure plasma jets

    SciTech Connect

    Hicks, R.; Jeong, J.; Babayan, S.; Schuetze, A.; Park, J.; Herrmann, H.; Henins, I.; Selwyn, G.

    1998-12-31

    Atmospheric-pressure plasma jets can be used for a wide range of materials processing applications, including surface cleaning and modification, selective etching, and thin-film deposition. The plasma source consists of two closely spaced electrodes through which helium and other gases flow (O{sub 2}, CF{sub 4}, etc.). A variety of electrode configurations can be used, and the source is suitable for continuous and large-area processing of materials. Another advantage of the plasma jet is that it achieves etching and deposition rates that are higher than those obtained in low-pressure plasmas. At the meeting, the plasma source will be described in detail, and results for several materials processing applications will be presented.

  18. Atmospheric budget of different elements in aerosol particles over Hungary

    NASA Astrophysics Data System (ADS)

    Molnár, A.; Mészáros, E.; Polyák, K.; Borbély-Kiss, I.; Koltay, E.; Szabó, Gy.; Horváth, Zs.

    The aim of this paper is to present the budget of seven elements (Cd, Cu, Mn, Ni, Pb, V and Zn) in the atmospheric aerosol over Hungary. The dry deposition is estimated on the basis of concentration and size distribution measurements and on dry deposition velocities available in the literature. The dry deposition velocity of two elements is obtained by transport model calculations. Wet deposition rates are determined by analyzing precipitation samples. The emissions of different elements necessary for budgeting are calculated by using statistical data on fossil fuel and gasoline burning, metallurgy, cement industry and waste incineration as well as on emission factors given by Pacyna (1984, Atmospheric Environment18, 41-50). It is found that the country is a net source for elements produced mostly by fossil fuel combustion while it is a net sink for elements released during industrial processes and automotive transport.

  19. Simulation on particle crushing of tailings material under high pressure

    NASA Astrophysics Data System (ADS)

    Liu, Hai-ming; Liu, Yi-ming; Yang, Chun-he; Cao, Jing

    2013-06-01

    With continuous increase of the high tailings dam, it has an important practical and theoretical significance to study the mechanical characteristics of the tailings material under high pressures. It is indicated that strength envelopes of the tailings material have a remarkable nonlinear characteristics through the triaxial test under high pressures. A further study stated that the particle crushing has a critical effect on the mechanical behavior of the tailings material. In order to quantitatively research its influence, the grain size distribution of the tailings material is analyzed for pre-and post-test and the particle crushing of the tailings material is measured. The particle flow code is employed to simulate and monitor the sample during testing. Firstly, a model which considers the particle crushing is built under the plane strain condition. Then, a series of biaxial numerical tests of the tailings specimen are simulated by using the model. It is found that the simulation result agrees with the triaxial test. Finally, a law between the particle crushing and strain of the tailings material under different confining pressures is obtained.

  20. Bronchiolitis caused by occupational and ambient atmospheric particles.

    PubMed

    Churg, Andrew; Wright, Joanne L

    2003-10-01

    Occupationally encountered mineral dusts such as asbestos, silica, silicates (talc, mica), and metals can produce a distinctive pattern of fibrosis and distortion of the small airways, particularly the distal membranous bronchioles (MB) and the respiratory bronchioles (RB). Recent reports show that the same types of changes, accompanied by considerable muscle hyperplasia, are found in individuals living in regions with high levels of particulate air pollutants (PM). Models and actual measurements suggest that these changes occur because the small airways are sites of high particle deposition, and inhaled and deposited particulates, including PM, enter the airway walls. Studies from our laboratory using a tracheal explant model have shown that, for many types of particles, entry into the airway wall causes expression of mediators that lead to airway wall fibrosis and airway wall smooth muscle hyperplasia, probably through oxidant mechanisms. These reactions are intrinsic properties of the particles and do not require exogenous inflammatory cells. There is considerable evidence that individuals with occupational exposure to a wide variety of mineral dusts, as well as individuals with chronic exposure to high levels of PM, develop chronic airflow obstruction. The type of small airway remodeling seen in particle-induced bronchiolitis appears to be one cause of chronic airflow obstruction in this setting. PMID:16088574

  1. Strong atmospheric new particle formation in winter, urban Shanghai, China

    NASA Astrophysics Data System (ADS)

    Xiao, S.; Wang, M. Y.; Yao, L.; Kulmala, M.; Zhou, B.; Yang, X.; Chen, J. M.; Wang, D. F.; Fu, Q. Y.; Worsnop, D. R.; Wang, L.

    2014-10-01

    Particle size distributions in the range of 1.34-615.3 nm were recorded from 25 November 2013 to 25 January 2014 in urban Shanghai, using a combination of one nano Condensation Nucleus Counter system (nCNC), one nano-Scanning Mobility Particle Sizer (SMPS), and one long-SMPS. Measurements of sulfur dioxide by an SO2 analyzer with pulsed UV fluorescence technique allowed calculation of sulfuric acid proxy. In addition, concentrations of ammonia were recorded with a Differential Optical Absorption Spectroscopy (DOAS). During this 62-day campaign, 13 NPF events were identified with strong burst of sub-3 nm particles and subsequent fast growth of newly formed particles. The observed nucleation rate (J1.34), formation rate of 3 nm particles (J3), and condensation sink (CS) were 112.4-271.0 cm-3 s-1, 2.3-19.2 cm-3 s-1, and 0.030-0.10 s-1, respectively. Subsequent cluster/nanoparticle growth showed a clear size dependence, with average values of GR1.35~1.39 (from the bin of 1.34-1.37 nm to the bin of 1.37-1.41 nm), GR1.39~1.46 (from 1.37-1.41 to 1.41-1.52 nm), GR1.46~1.70 (from 1.41-1.52 to 1.52-1.89 nm), GR1.70~2.39 (from 1.52-1.89 to 1.89-3.0 nm), GR2.39~7 (from 1.89-3.0 to 7 nm), and GR7~20 (from 7 to 20 nm) being 1.6 ± 1.0, 1.4 ± 2.2, 7.2 ± 7.1, 9.0 ± 11.4, 10.9 ± 9.8, and 11.4 ± 9.7 nm h-1, respectively. Correlation between nucleation rate (J1.34) and sulfuric acid proxy indicates that nucleation rate J1.34 was proportional to a 0.64 power of sulfuric acid proxy. Correlation between nucleation rate (J1.34) and gas-phase ammonia suggests that ammonia was associated with NPF events. The calculated sulfuric acid proxy was sufficient to explain the subsequent growth of 1.34-3 nm particles, but insufficient for particles exceeding this size range. Qualitatively, NPF events in urban Shanghai likely occur on days with low levels of PM2.5.

  2. Chemical Bonding and Structural Information of Black CarbonReference Materials and Individual Carbonaceous AtmosphericAerosols

    SciTech Connect

    Hopkins, Rebecca J.; Tivanski, Alexei V.; Marten, Bryan D.; Gilles, Mary K.

    2007-04-25

    The carbon-to-oxygen ratios and graphitic nature of a rangeof black carbon standard reference materials (BC SRMs), high molecularmass humic-like substances (HULIS) and atmospheric particles are examinedusing scanning transmission X-ray microscopy (STXM) coupled with nearedge X-ray absorption fine structure (NEXAFS) spectroscopy. UsingSTXM/NEXAFS, individual particles with diameter>100 nm are studied,thus the diversity of atmospheric particles collected during a variety offield missions is assessed. Applying a semi-quantitative peak fittingmethod to the NEXAFS spectra enables a comparison of BC SRMs and HULIS toparticles originating from anthropogenic combustion and biomass burns,thus allowing determination of the suitability of these materials forrepresenting atmospheric particles. Anthropogenic combustion and biomassburn particles can be distinguished from one another using both chemicalbonding and structural ordering information. While anthropogeniccombustion particles are characterized by a high proportion ofaromatic-C, the presence of benzoquinone and are highly structurallyordered, biomass burn particles exhibit lower structural ordering, asmaller proportion of aromatic-C and contain a much higher proportion ofoxygenated functional groups.

  3. Formation and growth of atmospheric particles at a forest site in the southeast US

    NASA Astrophysics Data System (ADS)

    Pillai, Priya; Walker, John; Khlystov, Andrey; Aneja, Viney

    2013-05-01

    Atmospheric particle size distribution measurements (10 ≤ aerodynamic diameter, Dp ≤ 250 nm), which took place above a loblolly pine plantation in the Southeast U.S. from November 2005 to September 2007, were made using Scanning Mobility Particle Sizer (SMPS). The size distributions were investigated to identify new particle formation and to classify the new particle formation episodes into different event classes based on the behavior of particle size distribution and particle growth pattern. About 69% of the observation days had nucleation. The event frequency was highest in spring and lowest in winter. The particle growth rate was highest in May (5.0 ± 3.6 nm hr-1) and lowest in February (1.2 ± 2.2 nm hr-1) with an annual average particle growth rate of 2.5 ± 0.3 nm hr-1. Nucleation frequency and event types are examined along with associated meteorological and chemical conditions.

  4. Atmospheric emission method of calculating the neutral atmosphere and charged particle densities in the upper atmosphere. Master's thesis

    SciTech Connect

    McElroy, K.L.

    1992-12-01

    This thesis presents a method for the determination of neutral gas densities in the ionosphere from rocket-borne measurements of UV atmospheric emissions. Computer models were used to calculate an initial guess for the neutral atmosphere. Using this neutral atmosphere, intensity profiles for the N2 (0,5) Vegard-Kaplan band, the N2 Lyman-Birge-Hopfield band system, and the OI2972 A line were calculated and compared with the March 1990 NPS MUSTANG data. The neutral atmospheric model was modified and the intensity profiles recalculated until a fit with the data was obtained. The neutral atmosphere corresponding to the intensity profile that fit the data was assumed to be the atmospheric composition prevailing at the time of the observation. The ion densities were then calculated from the neutral atmosphere using a photochemical model. The electron density profile calculated by this model was compared with the electron density profile measured by the U.S. Air Force Geophysics Laboratory at a nearby site.

  5. [Characterization of ultrafine particle size distribution in the urban atmosphere of Hangzhou in spring].

    PubMed

    Xie, Xiao-Fang; Sun, Zai; Yang, Wen-Jun

    2014-02-01

    Continuous measurement and analysis of the atmospheric ultrafine particle number concentration were performed in Hangzhou from March to May, 2012 by using the fast mobility particle sizer (FMPS). The result showed that daily number concentration of nucleation mode (5.6-20 nm), Aitken mode (20-100 nm), and accumulation mode (100-560 nm) particles, and total particles were 0.84 x 10(4), 1.08 x 10(4), 0.47 x 10(4) and 2.38 x 10(4) cm(-3) respectively. The concentration of Aitken mode particles was higher than that of other mode particles in sunny day. The nucleation mode and Aitken mode particles usually started to increase around 10:00-11:00 and ended up after 3-4 h. This indicated the solar radiation promoted the formation of new particles. Human activities caused the concentration distribution of each mode particles having an obvious difference between workdays and weekends. Combined with the meteorological factors, analysis showed that the wind speed and wind direction also directly influenced particulate concentration. The analysis of particulate concentration and visibility showed that the concentration of accumulation mode particles had a negative relationship with the atmospheric visibility, while those of nucleation mode and Aitken mode particles had a slight influence on it. PMID:24812930

  6. On the emission of amines from terrestrial vegetation in the context of atmospheric new particle formation

    NASA Astrophysics Data System (ADS)

    Neftel, Albrecht; Sintermann, Jörg

    2015-04-01

    Airborne amines, specifically methylamines (MAs), play a key role in atmospheric new particle formation (NPF) by stabilising small molecule clusters. Agricultural emissions are assumed to constitute the most important MA source, but given the short atmospheric residence time of MAs, they can hardly have a direct impact on NFP events observed in remote regions. High MA contents as well as emissions by plants have already been described in the 19th century. Strong MA emissions predominantly occur during flowering as part of a pollination strategy. The behaviour is species specific, but examples of such species are common and widespread. In addition, vegetative plant tissue exhibiting high amounts of MAs might potentially lead to significant emissions, and the decomposition of organic material could constitute another source for airborne MAs. These mechanisms would provide sources, which could be crucial for the amine's role in NPF, especially in remote regions. Knowledge about vegetation-related amine emissions is, however, very limited and thus it is also an open question how Global Change and the intensified cycling of reactive nitrogen over the last 200 years have altered amine emissions from vegetation with a corresponding effect on NPF.

  7. Heterogeneous chemistry of atmospheric mineral dust particles and their resulting cloud-nucleation properties

    NASA Astrophysics Data System (ADS)

    Sullivan, Ryan Christopher

    Mineral dust particles are a major component of tropospheric aerosol mass and affect regional and global atmospheric chemistry and climate. Dust particles experience heterogeneous reactions with atmospheric gases that alter the gas and particle-phase chemistry. These in turn influence the warm and cold cloud nucleation ability and optical properties of the dust particles. This dissertation investigates the atmospheric chemistry of mineral dust particles and their role in warm cloud nucleation through a combination of synergistic field measurements, laboratory experiments, and theoretical modeling. In-situ measurements made with a single-particle mass spectrometer during the ACE-Asia field campaign in 2001 provide the motivation for this work. The observed mixing state of the individual ambient particles with secondary organic and inorganic components is described in Chapter 2. A large Asian dust storm occurred during the campaign and produced dramatic changes in the aerosol's composition and mixing state. The effect of particle size and mineralogy on the atmospheric processing of individual dust particles is explored in Chapters 3 & 4. Sulfate was found to accumulate preferentially in submicron iron and aluminosilicate-rich dust particles, while nitrate and chloride were enriched in supermicron calcite-rich dust. The mineral dust (and sea salt particles) were also enriched in oxalic acid, the dominant component of water soluble organic carbon. Chapter 5 explores the roles of gas-phase photochemistry and partitioning of the diacids to the alkaline particles in producing this unique behavior. The effect of the dust's mixing state with secondary organic and inorganic components on the dust particles' solubility, hygroscopicity, and thus warm cloud nucleation properties is explored experimentally and theoretically in Chapter 6. Cloud condensation nucleation (CCN) activation curves revealed that while calcium nitrate and calcium chloride particles were very hygroscopic and CCN-active, due to the high solubility of these compounds, calcium sulfate and calcium oxalate were not. Particles composed of these two sparingly soluble compounds had apparent hygroscopicities similar to pure calcium carbonate. This implies that the commonly made assumption that all dust particles become more hygroscopic after atmospheric processing must be revisited. Calcium sulfate and oxalate represent two forms of aged mineral dust particles that remain non-hygroscopic and thus have poor CCN nucleation ability. The particle generation method (dry versus wet) was found to significantly affect the chemistry and hygroscopicity of the aerosolized particles. Finally, in Chapter 7 the timescale for the atmospheric conversion of insoluble calcite particles to soluble, CCN-active calcium nitrate particles was derived from aerosol flow tube experiments. The reaction rate is rapid was used to estimate the conversion of calcite particles to very hygroscopic particles can occur in just a few hours of exposure to tropospheric levels of nitric acid. This process will therefore be controlled by the availability of nitric acid and its precursors, as opposed to the available atmospheric reaction time.

  8. Optical properties, morphology and elemental chemical composition of atmospheric particles at T1 supersite on MILAGRO campaign

    NASA Astrophysics Data System (ADS)

    Carabali, G.; Mamani-Paco, R.; Castro, T.; Peralta, O.; Herrera, E.; Trujillo, B.

    2011-05-01

    Atmospheric particles were sampled at T1 supersite (19°43' N latitude, 98°58' W longitude, and 2340 m above sea level) during MILAGRO campaign. T1 was located at the north of Mexico City Metropolitan Area (MCMA). Aerosol sampling was done by placing transmission electron microscope (TEM) copper grids on the last 5 stages of an 8-stage MOUDI cascade impactor (d50 = 1.8, 1.0, 0.56, 0.32, and 0.18 μm). Samples were obtained at morning (06:00-09:00), noon (11:00-14:00), afternoon (16:00-19:00) and evening (21:00-24:00) local time. Absorption and scattering coefficients, and particles concentration (0.01-3 μm aerodynamic diameter) were measured simultaneously using a PASP absorption photometer (operated at 550 nm), a portable integrating nephelometer (at 530 nm) and a CNI particle counter. TEM images of particles were acquired at different magnifications using a CM 200 Phillips TEM-EDAX system. The morphology of atmospheric particles for two aerodynamic diameters (0.18 and 1.8 μm) was compared using border-based fractal dimension. Particles sampled under Mexico City pollution influence showed not much variability, suggesting the presence of more compact particles in smaller sizes (d50 = 1.8 μm) at the site. The presence of higher numbers of compact particles can be attributed to aerosol aging and secondary aerosol formation, among others. Under early morning conditions, smaller particles (d50 = 0.18 μm) had more irregular features resulting in a higher average fractal dimension. Energy dispersive X-ray spectroscopy (EDS) was used to determine the elemental composition of particles. EDS analysis in particles with d50 = 0.18 μm showed a higher content of carbonaceous material and relevant amounts of Si, Fe, K, and Co. This may indicate an impact from industrial and vehicle's emissions on atmospheric particles.

  9. Discrete particle swarm optimization with scout particles for library materials acquisition.

    PubMed

    Wu, Yi-Ling; Ho, Tsu-Feng; Shyu, Shyong Jian; Lin, Bertrand M T

    2013-01-01

    Materials acquisition is one of the critical challenges faced by academic libraries. This paper presents an integer programming model of the studied problem by considering how to select materials in order to maximize the average preference and the budget execution rate under some practical restrictions including departmental budget, limitation of the number of materials in each category and each language. To tackle the constrained problem, we propose a discrete particle swarm optimization (DPSO) with scout particles, where each particle, represented as a binary matrix, corresponds to a candidate solution to the problem. An initialization algorithm and a penalty function are designed to cope with the constraints, and the scout particles are employed to enhance the exploration within the solution space. To demonstrate the effectiveness and efficiency of the proposed DPSO, a series of computational experiments are designed and conducted. The results are statistically analyzed, and it is evinced that the proposed DPSO is an effective approach for the studied problem. PMID:24072983

  10. Chemical characterization of atmospheric particles and source apportionment in the vicinity of a steelmaking industry.

    PubMed

    Almeida, S M; Lage, J; Fernández, B; Garcia, S; Reis, M A; Chaves, P C

    2015-07-15

    The objective of this work was to provide a chemical characterization of atmospheric particles collected in the vicinity of a steelmaking industry and to identify the sources that affect PM10 levels. A total of 94 PM samples were collected in two sampling campaigns that occurred in February and June/July of 2011. PM2.5 and PM2.5-10 were analyzed for a total of 22 elements by Instrumental Neutron Activation Analysis and Particle Induced X-ray Emission. The concentrations of water soluble ions in PM10 were measured by Ion Chromatography and Indophenol-Blue Spectrophotometry. Positive Matrix Factorization receptor model was used to identify sources of particulate matter and to determine their mass contribution to PM10. Seven main groups of sources were identified: marine aerosol identified by Na and Cl (22%), steelmaking and sinter plant represented by As, Cr, Cu, Fe, Ni, Mn, Pb, Sb and Zn (11%), sinter plant stack identified by NH4(+), K and Pb (12%), an unidentified Br source (1.8%), secondary aerosol from coke making and blast furnace (19%), fugitive emissions from the handling of raw material, sinter plant and vehicles dust resuspension identified by Al, Ca, La, Si, Ti and V (14%) and sinter plant and blast furnace associated essentially with Fe and Mn (21%). PMID:25864153

  11. Microstructure of atmospheric particles revealed by TXM and a new mode of influenza virus transmission

    NASA Astrophysics Data System (ADS)

    Bao, L. M.; Zhang, G. L.; Lei, Q. T.; Li, Y.; Li, X. L.; Hwu, Y. K.; Yi, J. M.

    2015-09-01

    For control of influenza, firstly it is important to find the real virus transmission media. Atmospheric aerosol particles are presumably one of the media. In this study, three typical atmospheric inhaled particles in Shanghai were studied by the synchrotron based transmission X-ray microscopes (TXM). Three dimensional microstructure of the particles reveals that there are many pores contained in, particularly the coal combustion fly particles which may be possible virus carrier. The particles can transport over long distance and cause long-range infections due to its light weight. We suggest a mode which is droplet combining with aerosol mode. By this mode the transmission of global and pandemic influenzas and infection between inland avian far from population and poultry or human living in cities along coast may be explained.

  12. Secondary organic aerosol formation from toluene in an atmospheric hydrocarbon mixture: Water and particle seed effects

    NASA Astrophysics Data System (ADS)

    Kamens, Richard M.; Zhang, Haofei; Chen, Eric H.; Zhou, Yang; Parikh, Harshal M.; Wilson, Rebecca L.; Galloway, Katherine E.; Rosen, Elias P.

    2011-04-01

    Atmospherically relevant secondary organic aerosol (SOA) concentrations from toluene, in an urban hydrocarbon environment, with oxides of nitrogen in natural sunlight, were studied in a large outdoor chamber with different initial humidity and types of initial seed aerosols. Ammonium sulfate particles (38 μg m -3) in the presence of an atmospheric hydrocarbon mixture and NOx in sunlight under a dry atmosphere (%RH = 6 to 10%) show reduced SOA formation when compared to similar gas phase conditions with lower ammonium sulfate (7 μg m -3) and higher relative humidities (%RH 40 to 90%). No post particle nucleation (particles in the 6 to 10 nm range) was observed in either seeded system. When initial background particles levels were below 0.5 μg m -3 particle nucleation was observed. A new condensed aromatic kinetic chemical mechanism was developed to simulate experimental data. A particle water phase was highly related to SOA formation. Reasonable fits to the gas and total SOA concentrations emphasize the important impact of different initial particle seed levels and particle phase water when simulating SOA formation from aromatic compounds like toluene.

  13. Ligand-Driven Phase Separation in Binary Particle Brush Materials

    NASA Astrophysics Data System (ADS)

    Bockstaller, Michael; Schmitt, Michael; Zhang, Jianan; Yan, Jiajun; Matyjaszewski, Krzysztof

    The tethering of polymer chains to the surface of nanoparticles (to form so-called `particle brush materials') has emerged as an effective means to enable the bottom-up assembly of one-component hybrid materials with controlled microstructure and improved mechanical stability as well as novel optical or acoustic properties. The polymer-like interactions and response of these particle-brush materials suggest intriguing new opportunities to control structure formation in multicomponent particle mixtures. This contribution will demonstrate that polymer-ligand interactions can drive phase separation processes in mixed particle systems that share analogies to those of regular binary polymer blends. The role of particle size, density and degree of polymerization of tethered chains as well as the interaction parameter between the distinct tethered chains on the mechanism and kinetics of phase separation processes in mixed particle brush systems will be discussed. Ligand-driven phase separation will be shown to enable the efficient fabrication of monochromatic domain structured in mixed quantum dot systems that might find application in next generation quantum dot-enabled LEDs. Support by the National Science Foundation (via Grant DMR-1410845) is gratefully acknowledged.

  14. Particles, environments, and possible ecologies in the Jovian atmosphere

    NASA Technical Reports Server (NTRS)

    Sagan, C.; Salpeter, E. E.

    1976-01-01

    The possible existence of indigenous Jovian organisms is investigated by characterizing the relevant physical environment of Jupiter, discussing the chromophores responsible for the observed coloration of the planet, and analyzing some permissible ecological niches of hypothetical organisms. Values of the eddy diffusion coefficent are estimated separately for the convective troposphere and the more stable mesosphere, and equilibrium condensation is studied for compounds containing Na, Cl, or both. The photoproduction of chromophores and nonequilibrium organic molecules is analyzed, and the motion of hypothetical organisms is examined along with the diffusion of metabolites and the consequent growth of organisms. Four kinds of organisms are considered: primary photosynthetic autotrophs ('sinkers'), larger autotrophs or heterotrophs that actively maintain their pressure level ('floaters'), organisms that seek out others ('hunters'), and organisms that live at almost pyrolytic depths ('scavengers'). It is concluded that ecological niches for sinkers, floaters, and hunters appear to exist in the Jovian atmosphere.

  15. Electron Spectroscopy for Chemical Analysis (ESCA) study of atmospheric particles

    NASA Technical Reports Server (NTRS)

    Dillard, J. G.; Seals, R. D.; Wightman, J. P.

    1979-01-01

    The results of analyses by ESCA (Electron Spectroscopy for Chemical Analysis) on several Nuclepore filters which were exposed during air pollution studies are presented along with correlative measurements by Neutron Activation Analysis and Scanning Electron Microscopy. Samples were exposed during air pollution studies at Norfolk, Virginia and the NASA Kennedy Space Center (KSC). It was demonstrated that with the ESCA technique it was possible to identify the chemical (bonding) state of elements contained in the atmospheric particulate matter collected on Nuclepore filters. Sulfur, nitrogen, mercury, chlorine, alkali, and alkaline earth metal species were identified in the Norfolk samples. ESCA binding energy data for aluminum indicated that three chemically different types of aluminum are present in the launch and background samples from NASA-KSC.

  16. Quantitative characterization of spatial distribution of particles in materials: Application to materials processing

    NASA Technical Reports Server (NTRS)

    Parse, J. B.; Wert, John A.

    1990-01-01

    Most engineering materials contain second phase particles or fibers which serve to reinforce the matrix phase. The effect of reinforcements on material properties is usually analyzed in terms of the average volume fraction and spacing of reinforcements, quantities which are global microstructural characteristics. However, material properties can also depend on local microstructural characteristics; for example, on how uniformly the reinforcing phase is distributed in the material. The analysis method will then be applied to a materials processing problem to discover how processing parameters can be selected to maximize redistribution of the reinforcing phase during processing. Several mathematical analysis methods could be adapted to the problem of characterizing the distribution of particles in materials. A tessellation-based method was selected. In the first phase of the investigation, a software package was written to automate the analysis. Typical results are shown. The analysis technique allows the degree to which particles are clustered together, the size and spacing of particle clusters, and the particle density in clusters to be found. The analysis methods were applied to computer-generated distributions and to a few real particle-containing materials. Methods for analyzing a nonuniform particle distribution in a material can be applied to two broad classes of materials science problems: understanding how the resulting particle distribution affects properties. The analysis method described is applied to a materials processing problem: how to select extrusion conditions to maximize the redistribution of reinforcing particles that are initially nonuniformly distributed. In addition, the tessellation-based method to analyze star distributions in spiral galaxies was adapted, illustrating the diverse types of problems to which the analysis method can be applied.

  17. A new method for assessing the contribution of Primary Biological Atmospheric Particles to the mass concentration of the atmospheric aerosol.

    PubMed

    Perrino, Cinzia; Marcovecchio, Francesca

    2016-02-01

    Primary Biologic Atmospheric Particles (PBAPs) constitute an interesting and poorly investigated component of the atmospheric aerosol. We have developed and validated a method for evaluating the contribution of overall PBAPs to the mass concentration of atmospheric particulate matter (PM). The method is based on PM sampling on polycarbonate filters, staining of the collected particles with propidium iodide, observation at epifluorescence microscope and calculation of the bioaerosol mass using a digital image analysis software. The method has been also adapted to the observation and quantification of size-segregated aerosol samples collected by multi-stage impactors. Each step of the procedure has been individually validated. The relative repeatability of the method, calculated on 10 pairs of atmospheric PM samples collected side-by-side, was 16%. The method has been applied to real atmospheric samples collected in the vicinity of Rome, Italy. Size distribution measurements revealed that PBAPs was mainly in the coarse fraction of PM, with maxima in the range 5.6-10 μm. 24-h samples collected during different period of the year have shown that the concentration of bioaerosol was in the range 0.18-5.3 μg m(-3) (N=20), with a contribution to the organic matter in PM10 in the range 0.5-31% and to the total mass concentration of PM10 in the range 0.3-18%. The possibility to determine the concentration of total PBAPs in PM opens up interesting perspectives in terms of studying the health effects of these components and of increasing our knowledge about the composition of the organic fraction of the atmospheric aerosol. PMID:26680730

  18. Atmospheric fate and transport of fine volcanic ash: Does particle shape matter?

    NASA Astrophysics Data System (ADS)

    White, C. M.; Allard, M. P.; Klewicki, J.; Proussevitch, A. A.; Mulukutla, G.; Genareau, K.; Sahagian, D. L.

    2013-12-01

    Volcanic ash presents hazards to infrastructure, agriculture, and human and animal health. In particular, given the economic importance of intercontinental aviation, understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance. Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating interior engine parts causing damage and potential failure. The time fine ash stays in the atmosphere depends on its terminal velocity. Existing models of ash terminal velocities are based on smooth, quasi-spherical particles characterized by Stokes velocity. Ash particles, however, violate the various assumptions upon which Stokes flow and associated models are based. Ash particles are non-spherical and can have complex surface and internal structure. This suggests that particle shape may be one reason that models fail to accurately predict removal rates of fine particles from volcanic ash clouds. The present research seeks to better parameterize predictive models for ash particle terminal velocities, diffusivity, and dispersion in the atmospheric boundary layer. The fundamental hypothesis being tested is that particle shape irreducibly impacts the fate and transport properties of fine volcanic ash. Pilot studies, incorporating modeling and experiments, are being conducted to test this hypothesis. Specifically, a statistical model has been developed that can account for actual volcanic ash size distributions, complex ash particle geometry, and geometry variability. Experimental results are used to systematically validate and improve the model. The experiments are being conducted at the Flow Physics Facility (FPF) at UNH. Terminal velocities and dispersion properties of fine ash are characterized using still air drop experiments in an unconstrained open space using a homogenized mix of source particles. Dispersion and sedimentation dynamics are quantified using particle image velocimetry (PIV). Scanning Electron Microscopy (SEM) of ash particles collected in localized deposition areas is used to correlate the PIV results to particle shape. In addition, controlled wind tunnel experiments are used to determine particle fate and transport in a turbulent boundary layer for a mixed particle population. Collectively, these studies will provide an improved understanding of the effects of particle shape on sedimentation and dispersion, and foundational data for the predictive modeling of the fate and transport of fine ash particles suspended in the atmosphere.

  19. The atmospheric cosmic- and solar energetic particle radiation environment at aircraft altitudes.

    PubMed

    O'Brien, K; Friedberg, W; Smart, D F; Sauer, H H

    1998-01-01

    Galactic cosmic rays interact with the solar wind, the earth's magnetic field and hadron, lepton and photon fields at aircraft altitudes. In addition to cosmic rays, energetic particles generated by solar activity bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as atmospheric cosmic rays. We have used a code based on transport theory to calculate atmospheric cosmic-ray quantities and compared them with experimental data. Agreement with these data is seen to be good. We have then used this code to calculate equivalent doses to aircraft crews. We have also used the code to calculate radiation doses from several large solar energetic particle events which took place in 1989, including the very large event that occurred on September 29th and 30th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory. PMID:11542893

  20. Genesis Concentrator Target Particle Contamination Mapping and Material Identification

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Rodriquez, M. C.; Allton, J. H.

    2007-01-01

    The majority of surface particles were found to be < 5 microns in diameter with increasing numbers close to the optical resolution limit of 0.3 microns. Acceleration grid EDS results show that the majority of materials appear to be from the SRC shell and SLA materials which include carbon-carbon fibers and Si-rich microspheres in a possible silicone binder. Other major debris material from the SRC included white paint, kapton, collector array fragments, and Al. Image analysis also revealed that SRC materials were also found mixed with the Utah mud and salt deposits. The EDS analysis of the acceleration grid showed that particles < 1 m where generally carbon based particles. Chemical cleaning techniques with Xylene and HF in an ultrasonic bath are currently being investigated for removal of small particles by the Genesis science team as well as ultra-pure water megasonic cleaning by the JSC team [4]. Removal of organic contamination from target materials is also being investigated by the science team with the use of UV-ozone cleaning devices at JSC and Open University [5]. In preparation for solar wind oxygen analyses at UCLA and Open University [1, 2], surface particle contamination on three Genesis concentrator targets was closely examined to evaluate cleaning strategies. Two silicon carbide (Genesis sample # 60001 and 60003) and one chemical vapor deposited (CVD) 13C concentrator target (60002) were imaged and mosaic mapped with optical microscopes. The resulting full target mosaic images and particle feature maps were subsequently compared with non-flight, but flight-like, concentrator targets and sample return capsule (SRC) materials. Contamination found on the flown concentrator acceleration grid was further examined using a scanning electron microscope (SEM). Energy dispersive X-ray spectroscopy (EDS) for particle identification was subsequently compared with the optical images from the flown targets. Figure 1 show that all three targets imaged in this report are fully intact and do not show any signs of material fractures. However, previous ellipsometry results and overview imaging of both flown SiC targets show a solar wind irradiation gradient from the center focal point to the outer edge [3]. In addition, due to the hard landing, each target has experienced varying degrees of impacts, scratches, and particle debris from the spacecraft and Utah impact site.

  1. Origin of nitrocatechols and alkylated-nitrocatechols in atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Marchand, Nicolas; Sylvestre, Alexandre; Ravier, Sylvain; Detournay, Anais; Bruns, Emily; Temime-Roussel, Brice; Slowik, Jay; El Haddad, Imad; Prevot, Andre

    2013-04-01

    Biomass burning constitutes one of the major sources of aerosol particles in most of the environments during winter. If a lot of information is available in the literature on the primary fraction of biomass burning aerosol particles, almost nothing is known regarding the formation of Secondary Organic Aerosol (SOA) from the chemical mixture emitted by this source. Recently methylated nitrocatechol have been identified in atmospheric particles collected in winter. These compounds are strongly associated with biomass burning tracers such as levoglucosan and are suspected to be of secondary origin since they can be formed through the oxidation of cresol significantly emitted by biomass burning. However, nitrocatechols are particularly difficult to analyze using classical techniques like HPLC-MS or GC-MS. In the present study, we adopt a new analytical approach. Direct analysis in real time (DART), introduced by Cody et al. (2005), allows direct analysis of gases, liquids, solids and materials on surfaces. Thus, for particles collected onto filters, the sample preparation step is simplified as much as possible, avoiding losses and reducing to the minimum the analytical procedure time. Two analytic modes can be used. In positive mode, [MH]+ ions are formed by proton transfer reaction ; whereas in negative ionization mode, [MH]-, M- and [MO2]- ions are formed. DART source enables soft ionization and produces simple mass spectra suitable for analysis of complex matrices, like organic aerosol, in only a few seconds. For this study, the DART source was coupled to a Q-ToF mass spectrometer (Synapt G2 HDMS, Waters), with a mass resolution up to 40 000. The analysis of atmospheric aerosol samples, collected in Marseille during winter 2011 (APICE project), with the DART/Q-ToF approach highlighted the abundance of nitrocatechols and alkylated nitrocatechols. Their temporal trends were also very similar to those of levoglucosan or dihydroabietic acid well known tracers of biomass burning aerosol. If their biomass burning origin's is clearly established, their secondary origin remains still not totally clear. Smog chamber experiments were then conducted in the PSI facilities to investigate the aging of biomass burning emissions. The analysis of samples collected during these experiments using the DART/Q-ToF approach, confirmed that nitrocatechols and methylated nitrocatechols originate from biomass burning processes. More importantly our results confirm that nitrocatechols and their methylated derivatives are quasi exclusively from secondary origin. Considering the abundance of biomass burning primary aerosol, and the large fraction of unexplained SOA, this result is of prime importance. Cody. R., Laramée J. Nilles J. and Durst H. : Direct Analysis in Real Time (DARTtm) Mass Spectrometry, JOEL news, 2005, 40, 1, 8-12. Kitanovski Z., Grgic I., Yasmeen F., Claeys M. and Cusak A.: Development of a liquid chromatographic method based on ultraviolet-visible and electrospray ionization mass spectrometric detection for the identification of nitrocatechols and related tracers ion biomass burning atmospheric organic aerosol, Rapid Communication in Mass Spectrometry, 2012, 26, 793-804. Iinuma Y., Boge O., Grafe R. and Herrmann H.: Methyl-nitrocatechols : Atmospheric tracer coumpounds for biomass burnig secondary organic aerosols, Environmental Science and Technology, 2010, 44, 8453-8459.

  2. [Atmospheric Particle Retaining Function of Common Deciduous Tree Species Leaves in Beijing].

    PubMed

    Wang, Bing; Wang, Xiao-yan; Niu, Xiang; Zhang, Wei-kang; Wang, Jin-song

    2015-06-01

    In order to explore the atmospheric particle-retaining function of common deciduous tree species leaves in Beijing, six typical tree species (Populus, Robinia pseudoacacia, Koelreuteria paniculata, Salix babylonica, Acer truncatum, Ginkgo biloba) were chosen to measure retaining amount of unit leaf area of air total suspended particles (TSP), coarse particles and fine particulate with aerosol generator (QRJZFSQ-I). The results showed that (1) All six tree species leaves had a certain level of retaining ability to different sizes of atmospheric particles, and different species exhibited some differences. For different sizes of atmospheric particle, retaining amounts of unit leaf area were higher in Koelreuteria paniculata and Robinia pseudoacacia than those of other four species, and the amount of Populus was the lowest among all tree species; (2) The retaining amount of unit leaf area for different tree species was not entirely increased with sampling time. The retaining amounts of TSP and coarse particles for all tree species on the eighth day after rain were significantly higher than those on the fifth day after rain, however, the retaining amount of fine particles was not significantly different under different sampling times. In order to select deciduous tree species for ecological management of air pollution in Beijing, Koelreuteria paniculata should be considered as the priority, followed by Robinia pseudoacacia, compared with Ginkgo biloba, Salix babylonica, Acer truncatum and Populus. PMID:26387301

  3. Topical Issue on Optical Particle Characterization and Remote Sensing of the Atmosphere: Part I

    NASA Technical Reports Server (NTRS)

    Videen, Gorden; Kocifaj, Miroslav; Sun, Wenbo; Kai, Kenji; Kawamoto, Kazuaki; Horvath, Helmuth; Mishchenko, Michael

    2015-01-01

    Increasing our understanding of the Earth-atmosphere system has been a scientific and political priority for the last few decades. This system not only touches on environmental science, but it has applicability to our broader understanding of planetary atmospheres in general. While this issue focuses primarily on electromagnetics, other fundamental fields of science, including fluid and thermodynamics play major roles. In recent years, significant research efforts have led to advances in the fields of radiative transfer and electromagnetic scattering from irregularly shaped particles. Recently, several workshops and small conferences have taken place to promote the fusion of these efforts. Late in 2013, for instance, two such meetings took place. The Optical Characterization of Atmospheric Aerosols (OCAA) meeting took place in Smolenice, Slovakia to promote a better understanding of microphysical properties of aerosol particles, and the characterization of such atmospheric particles using optical techniques. A complementary conference was organized in Nagoya, Japan, the 3rd International Symposium on Atmospheric Light Scattering and Remote Sensing (ISALSaRS), whose goal is to fuse the advances achieved in particle characterization with remote-sensing techniques. While the focus of these meetings is slightly different, they represent the same aspects of this rapidly growing field. This Topical Issue is the first of two parts. Within this issue we analyze different aspects of the problem of atmospheric characterization and present a broad overview of the topical area. Research includes theory and experiment, ranging from fundamental microphysical properties of individual aerosol particles to broad characterizations of atmospheric properties. Since this is an active field, we also have encouraged the submission of ideas for new methodologies that may represent the future of the field.

  4. Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere.

    PubMed

    Almeida, João; Schobesberger, Siegfried; Kürten, Andreas; Ortega, Ismael K; Kupiainen-Määttä, Oona; Praplan, Arnaud P; Adamov, Alexey; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Donahue, Neil M; Downard, Andrew; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Guida, Roberto; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Henschel, Henning; Jokinen, Tuija; Junninen, Heikki; Kajos, Maija; Kangasluoma, Juha; Keskinen, Helmi; Kupc, Agnieszka; Kurtén, Theo; Kvashin, Alexander N; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Leppä, Johannes; Loukonen, Ville; Makhmutov, Vladimir; Mathot, Serge; McGrath, Matthew J; Nieminen, Tuomo; Olenius, Tinja; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Riipinen, Ilona; Rissanen, Matti; Rondo, Linda; Ruuskanen, Taina; Santos, Filipe D; Sarnela, Nina; Schallhart, Simon; Schnitzhofer, Ralf; Seinfeld, John H; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjo; Virtanen, Annele; Vrtala, Aron; Wagner, Paul E; Weingartner, Ernest; Wex, Heike; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Yli-Juuti, Taina; Carslaw, Kenneth S; Kulmala, Markku; Curtius, Joachim; Baltensperger, Urs; Worsnop, Douglas R; Vehkamäki, Hanna; Kirkby, Jasper

    2013-10-17

    Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation. PMID:24097350

  5. Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations

    NASA Astrophysics Data System (ADS)

    Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

    1996-08-01

    An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road dust, tire wear, brake lining dust, meat cooking operations, industrial oil-fired boilers, roofing tar pots, natural gas combustion in residential homes, cigarette smoke, fireplaces burning oak and pine wood, and plant leaf abrasion products. These primary fine particle source emissions were supplied to a computer-based model that simulates atmospheric transport, dispersion, and dry deposition based on the time series of hourly wind observations and mixing depths. Monthly average fine particle organic compound concentrations that would prevail if the primary organic aerosol were transported without chemical reaction were computed for more than 100 organic compounds within an 80 km × 80 km modeling area centered over Los Angeles. The monthly average compound concentrations predicted by the transport model were compared to atmospheric measurements made at monitoring sites within the study area during 1982. The predicted seasonal variation and absolute values of the concentrations of the more stable compounds are found to be in reasonable agreement with the ambient observations. While model predictions for the higher molecular weight polycyclic aromatic hydrocarbons (PAH) are in agreement with ambient observations, lower molecular weight PAH show much higher predicted than measured atmospheric concentrations in the particle phase, indicating atmospheric decay by chemical reactions or evaporation from the particle phase. The atmospheric concentrations of dicarboxylic acids and aromatic polycarboxylic acids greatly exceed the contributions that are due to direct emissions from primary sources, confirming that these compounds are principally formed by atmospheric chemical reactions.

  6. Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere

    NASA Astrophysics Data System (ADS)

    Almeida, João; Schobesberger, Siegfried; Kürten, Andreas; Ortega, Ismael K.; Kupiainen-Määttä, Oona; Praplan, Arnaud P.; Adamov, Alexey; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Donahue, Neil M.; Downard, Andrew; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C.; Franchin, Alessandro; Guida, Roberto; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Henschel, Henning; Jokinen, Tuija; Junninen, Heikki; Kajos, Maija; Kangasluoma, Juha; Keskinen, Helmi; Kupc, Agnieszka; Kurtén, Theo; Kvashin, Alexander N.; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Leppä, Johannes; Loukonen, Ville; Makhmutov, Vladimir; Mathot, Serge; McGrath, Matthew J.; Nieminen, Tuomo; Olenius, Tinja; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Riipinen, Ilona; Rissanen, Matti; Rondo, Linda; Ruuskanen, Taina; Santos, Filipe D.; Sarnela, Nina; Schallhart, Simon; Schnitzhofer, Ralf; Seinfeld, John H.; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjo; Virtanen, Annele; Vrtala, Aron; Wagner, Paul E.; Weingartner, Ernest; Wex, Heike; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Yli-Juuti, Taina; Carslaw, Kenneth S.; Kulmala, Markku; Curtius, Joachim; Baltensperger, Urs; Worsnop, Douglas R.; Vehkamäki, Hanna; Kirkby, Jasper

    2013-10-01

    Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.

  7. Detection of special nuclear materials with the associate particle technique

    SciTech Connect

    Carasco, Cedric; Deyglun, Clement; Perot, Bertrand; Eleon, Cyrille; Normand, Stephane; Sannie, Guillaume; Boudergui, Karim; Corre, Gwenole; Konzdrasovs, Vladimir; Pras, Philippe

    2013-04-19

    In the frame of the French trans-governmental R and D program against chemical, biological, radiological, nuclear and explosives (CBRN-E) threats, CEA is studying the detection of Special Nuclear Materials (SNM) by neutron interrogation with fast neutrons produced by an associated particle sealed tube neutron generator. The deuterium-tritium fusion reaction produces an alpha particle and a 14 MeV neutron almost back to back, allowing tagging neutron emission both in time and direction with an alpha particle position-sensitive sensor embedded in the generator. Fission prompt neutrons and gamma rays induced by tagged neutrons which are tagged by an alpha particle are detected in coincidence with plastic scintillators. This paper presents numerical simulations performed with the MCNP-PoliMi Monte Carlo computer code and with post processing software developed with the ROOT data analysis package. False coincidences due to neutron and photon scattering between adjacent detectors (cross talk) are filtered out to increase the selectivity between nuclear and benign materials. Accidental coincidences, which are not correlated to an alpha particle, are also taken into account in the numerical model, as well as counting statistics, and the time-energy resolution of the data acquisition system. Such realistic calculations show that relevant quantities of SNM (few kg) can be distinguished from cargo and shielding materials in 10 min acquisitions. First laboratory tests of the system under development in CEA laboratories are also presented.

  8. Detection of special nuclear materials with the associate particle technique

    NASA Astrophysics Data System (ADS)

    Carasco, Cédric; Deyglun, Clément; Pérot, Bertrand; Eléon, Cyrille; Normand, Stéphane; Sannié, Guillaume; Boudergui, Karim; Corre, Gwenolé; Konzdrasovs, Vladimir; Pras, Philippe

    2013-04-01

    In the frame of the French trans-governmental R&D program against chemical, biological, radiological, nuclear and explosives (CBRN-E) threats, CEA is studying the detection of Special Nuclear Materials (SNM) by neutron interrogation with fast neutrons produced by an associated particle sealed tube neutron generator. The deuterium-tritium fusion reaction produces an alpha particle and a 14 MeV neutron almost back to back, allowing tagging neutron emission both in time and direction with an alpha particle position-sensitive sensor embedded in the generator. Fission prompt neutrons and gamma rays induced by tagged neutrons which are tagged by an alpha particle are detected in coincidence with plastic scintillators. This paper presents numerical simulations performed with the MCNP-PoliMi Monte Carlo computer code and with post processing software developed with the ROOT data analysis package. False coincidences due to neutron and photon scattering between adjacent detectors (cross talk) are filtered out to increase the selectivity between nuclear and benign materials. Accidental coincidences, which are not correlated to an alpha particle, are also taken into account in the numerical model, as well as counting statistics, and the time-energy resolution of the data acquisition system. Such realistic calculations show that relevant quantities of SNM (few kg) can be distinguished from cargo and shielding materials in 10 min acquisitions. First laboratory tests of the system under development in CEA laboratories are also presented.

  9. Topical issue on optical particle characterization and remote sensing of the atmosphere: Part I

    NASA Astrophysics Data System (ADS)

    Videen, Gorden; Kocifaj, Miroslav; Sun, Wenbo; Kai, Kenji; Kawamoto, Kazuaki; Horvath, Helmuth; Mishchenko, Michael

    2015-01-01

    Increasing our understanding of the Earth-atmosphere system has been a scientific and political priority for the last few decades. This system not only touches on environmental science, but it has applicability to our broader understanding of planetary atmospheres in general. While this issue focuses primarily on electromagnetics, other fundamental fields of science, including fluid and thermodynamics play major roles. In recent years, significant research efforts have led to advances in the fields of radiative transfer and electromagnetic scattering from irregularly shaped particles. Recently, several workshops and small conferences have taken place to promote the fusion of these efforts. Late in 2013, for instance, two such meetings took place. The Optical Characterization of Atmospheric Aerosols (OCAA) meeting took place in Smolenice, Slovakia to promote a better understanding of microphysical properties of aerosol particles, and the characterization of such atmospheric particles using optical techniques. A complementary conference was organized in Nagoya, Japan, the 3rd International Symposium on Atmospheric Light Scattering and Remote Sensing (ISALSaRS), whose goal is to fuse the advances achieved in particle characterization with remote-sensing techniques. While the focus of these meetings is slightly different, they represent the same aspects of this rapidly growing field.

  10. Evidence for the role of organics in aerosol particle formation under atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Baltensperger, Urs

    2010-05-01

    New particle formation in the atmosphere is an important parameter in governing the radiative forcing of atmospheric aerosols. However, detailed nucleation mechanisms remain still ambiguous, as laboratory data have so far not been successful in explaining atmospheric nucleation. We investigated the formation of new particles in a smog chamber simulating the photochemical formation of H2SO4 and organic condensable species. Nucleation occurs at H2SO4 concentrations similar to the ones found in the ambient atmosphere during nucleation events. The measured particle formation rates are proportional to the product of the concentrations of H2SO4 and an organic molecule. This suggests that only one H2SO4 molecule and one organic molecule are involved in the rate limiting step of the observed nucleation process. Parameterizing this process in a global aerosol model results in substantially better agreement with ambient observations compared to control runs. Reference: Axel Metzger, Bart Verheggen, Josef Dommen, Jonathan Duplissy, Andre S. H. Prevot, Ernest Weingartner, Ilona Riipinen, Markku Kulmala, Dominick V. Spracklen, Kenneth S. Carslaw, and Urs Baltensperger, Evidence for the role of organics in aerosol particle formation under atmospheric conditions, Proc. Natl. Acad. Sci. USA, 107 (2010), www.pnas.org/cgi/doi/10.1073/pnas.0911330107.

  11. Characterizing Biological Particles in the Atmosphere at two Sites in Colorado

    NASA Astrophysics Data System (ADS)

    Garcia, E.; Prenni, A. J.; Prenni, J.; Rivest, J.; Demott, P. J.; Kreidenweis, S. M.

    2010-12-01

    The composition and distribution of primary biological aerosol particles (PBAPs) in the atmosphere is constantly changing due to both natural and anthropogenic activities. In this presentation, we will describe measurements aimed at better characterizing this population at Manitou Experimental Forest, in Pike National Forest in Colorado and in Fort Collins, CO. This work is part of the larger Biosphere-atmosphere Exchange of Aerosols within Cloud, Carbon and Hydrologic cycles, including Organics and Nitrogen (BEACHON) field study program, which is aimed at studying the connections between the biogeochemical cycling of carbon and water in semi-arid regions of the Western U.S. To this end, we are collecting PBAP with SKC impingers into water, which are subsequently analyzed by flow cytometery to determine the atmospheric biological particle concentration. Further, we are generating a gene library of the small subunit RNA genes to speciate the PBAPs in our collected samples using Sanger sequencing. These experiments are performed throughout the year to better understand seasonal variability of atmospheric microbial communities at the selected sites. A small handful of PBAPs have been found to be some of the best ice nucleators in the atmosphere, inducing ice nucleation as high as -2oC; these particles may play pivotal roles in influencing ice formation in cold clouds and, thereby, climate. Preliminary data will be presented aimed at better characterizing this important subset of biological particles.

  12. Preparation and characterization of energetic materials coated superfine aluminum particles

    NASA Astrophysics Data System (ADS)

    Liu, Songsong; Ye, Mingquan; Han, Aijun; Chen, Xin

    2014-01-01

    This work is devoted to protect the activity of aluminum in solid rocket propellants by means of solvent/non-solvent method in which nitrocellulose (NC) and Double-11 (shortened form of double-base gun propellant, model 11) have been used as coating materials. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of coated Al particles. Other characterization data of coated and uncoated Al particles, such as infrared absorption spectrum, laser particle size analysis and the active aluminum content were also studied. The thermal behavior of pure and coated aluminum samples have also been studied by simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC). The results indicated that: superfine aluminum particles could be effectively coated with nitrocellulose and Double-11 through a solvent/non-solvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 20-50 nm. The active aluminum content of different coated samples was measured by means of oxidation-reduction titration method. The results showed that after being stored in room temperature and under 50% humidity condition for about 4months the active aluminum content of coated Al particles decreased from 99.8 to 95.8% (NC coating) and 99.2% (Double-11 coating) respectively. Double-11 coating layer had a much better protective effect. The TG-DTA and DSC results showed that the energy amount and energy release rate of NC coated and Double-11 coated Al particles were larger than those of the raw Al particles. Double-11 coated Al particles have more significant catalytic effect on the thermal decomposition characters of AP than that of NC coated Al particles. These features accorded with the energy release characteristics of solid propellant.

  13. HIGHWAY MOTOR VEHICLES AS SOURCES OF ATMOSPHERIC PARTICLES: PROJECTED TRENDS 1977 TO 2000

    EPA Science Inventory

    Highway motor vehicle emissions contribute to the total atmospheric particulate burden. The possible health and welfare effects of these emissions depend upon their composition and concentration in the atmosphere, the exposure of man and materials, and in some instances the lengt...

  14. Are coarse particles unexpected common reservoirs for some atmospheric anthropogenic trace elements? A case study

    NASA Astrophysics Data System (ADS)

    Catinon, Mickaël; Ayrault, Sophie; Boudouma, Omar; Bordier, Louise; Agnello, Gregory; Reynaud, Stéphane; Tissut, Michel

    2013-08-01

    Without specific experimental equipment, it is very difficult to sample long-term atmospheric deposits on a pure state. That is why the composition of air-transferred solid material accumulated for 40 years in the 2 m-high walls, pierced with numerous holes of an outdoor public shelter, Grenoble city, France, was studied. An appropriate fractionation procedure allowed to obtain several fractions which were i) a sand fraction (8.3%) (fraction A), ii) a large mass of organic matter corresponding mostly to large fragments (>250 μm) of plant origin (66.7%) (fraction B) or to pollen fraction C (0.4%), iii) a slowly depositing organo-clay fraction (20%) (fractions D1 and D2) and iv) a solution mixed with non-settable particles (4.3%) (fraction E). The composition of each fraction was determined for 20 elements. The sand fraction showed very high concentrations specifically in Cu, Pb and Fe corresponding respectively to 81.5, 48.2 and 35.2% of the samples content in these elements. In contrast, Cd and Zn were mainly accumulated in the fraction B (67.5 and 62.2%, respectively). The scanning electron microscopy coupled to energy dispersive X-ray analysis (SEM-EDX) study of the fraction A showed the presence of large particles bearing Pb and Fe, particles rich in Cu and typical fly ashes originating mostly from iron industry. Most of these particles had a crystalline shape suggesting that they were formed after emission at a high temperature. The Pb-Fe-Cu deposit seen in fraction A likely originates from the neighbouring road surface contaminated by car traffic for several decades. The 206Pb/207Pb ratio (1.146 ± 0.004) showed that in the coarse sandy fraction A, Pb was represented at 65% by non-gasoline lead and 35% by "gasoline" lead emitted before 1999. The fraction A particles can only be transported on a limited distance by high magnitude events. They constitute a large reservoir for Cu and Pb and may play a major role in the long-term contamination of urban soils.

  15. Method and apparatus for making articles from particle based materials

    DOEpatents

    Moorhead, A.J.; Menchhofer, P.A.

    1995-12-19

    A method and apparatus are disclosed for the production of articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with the invention, a thermally settable slurry containing a relatively high concentration of the particles is conveyed through an elongate flow area having a desired cross-sectional configuration. The slurry is heated as it is advanced through the flow area causing the slurry to set or harden in a shape which conforms to the cross-sectional configuration of the flow area. The material discharges from the flow area as a self-supporting solid of near net final dimensions. The article may then be sintered to consolidate the particles and provide a high density product. 10 figs.

  16. Method and apparatus for making articles from particle based materials

    DOEpatents

    Moorhead, Arthur J.; Menchhofer, Paul A.

    1995-01-01

    A method and apparatus for the production of articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with the invention, a thermally settable slurry containing a relatively high concentration of the particles is conveyed through an elongate flow area having a desired cross-sectional configuration. The slurry is heated as it is advanced through the flow area causing the slurry to set or harden in a shape which conforms to the cross-sectional configuration of the flow area. The material discharges from the flow area as a self-supporting solid of near net final dimensions. The article may then be sintered to consolidate the particles and provide a high density product.

  17. Explicit particle-dynamics model for granular materials

    SciTech Connect

    Walton, O.R.

    1982-05-01

    Discrete-particle simulation of granular-material motion is developing into a viable method for studying how various interparticulate forces affect the bulk behavior of granular solids. A two-dimensional, polygonal-particle computer model, developed from the ideas of Cundall (1976), and incorporating other techniques from molecular dynamics, is being used in a study of the flow behavior of rubblized oil shale. Direct comparison with physical tests involving multiblock systems have verified the model's ability to predict the motion of real materials. Computer generated movies and high-speed motion pictures of physical tests involving gravity flow of 2-dimensional polygonal particles show formation of temporary arches followed by dynamic rupture and reformation of new arches. Direct shear tests on oil-shale rubble involving very large displacements indicate significant circulatory motion in the rubble. Computer simulation of the direct shear tests show similar behavior.

  18. [Research Progress in Analytical Technology for Heavy Metals in Atmospheric Particles].

    PubMed

    Wang, Yu-jie; Tu, Zhen-quan; Zhou, Li; Chi, Yong-jie; Luo, Qin

    2015-04-01

    Atmospheric particles have become the primary atmospheric pollutions, of which the heavy metals, owing to non-degradability and hysteresis, a serious threat to human life and natural environment, have become a hot research issue currently. The analytical methods of heavy metals in atmospheric particles are summarized in the present review, including atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry, neutron activation analysis, fluorescence spectrometry, glow discharge atomic emission spectrometry, microwave plasma atomic emission spectrometry, and laser induced breakdown spectroscopy, and some proposals are tried to make for improving the shortcomings of these technologies: continuum source Atomic absorption spectrometry for simultaneously measuring multi-elements, atomic emission spectrometry for direct determination of particulates, high resolution laser ablation inductively coupled plasma mass spectrometry for determination of solid samples, low scattering synchrotron fluorescence spectrum for determination of atmospheric particulate matter and k0 neutron activation analysis for determination of radioactive elements in the troposphere Analysis techniques of heavy metals in atmospheric particulate matter are promoted to develop toward being real-time, fast, low- detection-limit, direct-measurement and simple-operation due to the spatial and temporal distribution difference of the heavy metals in atmospheric particles and human requirement for improvement of ambient air quality as well as rapid development of modern instrument science and technology. PMID:26197596

  19. Exoelectronic emission of particles of lunar surface material

    NASA Technical Reports Server (NTRS)

    Mints, R. I.; Alimov, V. I.; Melekhin, V. P.; Milman, I. I.; Kryuk, V. I.; Kunin, L. L.; Tarasov, L. S.

    1974-01-01

    A secondary electron multiplier was used to study the thermostimulated exoelectronic emission of particles of lunar surface material returned by the Soviet Luna 16 automatic station. The natural exoemission from fragments of slag, glass, anorthosite, and a metallic particle was recorded in the isochronic and isothermal thermostimulation regimes. The temperature of emission onset depended on the type of regolith fragment. For the first three particles the isothermal drop in emission is described by first-order kinetic equations. For the anorthosite fragment, exoemission at constant temperature is characterized by a symmetric curve with a maximum. These data indicate the presence of active surface defects, whose nature can be due to the prehistory of the particles.

  20. Ionization of the Earth's Upper Atmosphere in Large Energetic Particle Events

    NASA Astrophysics Data System (ADS)

    Wolff, E.; Burrows, J.; Kallenrode, M.; von Koenig, M.; Kuenzi, K. F.; Quack, M.

    2001-12-01

    Energetic charged particles ionize the upper terrestrial atmosphere. Sofar, chemical consequences of precipitating particles have been discussed for solar protons with energies up to a few hundred MeV. We present a refined model for the interaction of energetic particles with the atmosphere based on a Monte-Carlo simulation. The model includes higher energies and other particle species, such as energetic solar electrons. Results are presented for well-known solar events, such as July 14, 2000, and are extrapolated to extremely large events, such as Carrington's white light flare in 1859, which from ice cores has been identified ass the largest impulsive NO3 event in the interval 1561 -- 1994 (McCracken et al., 2001).

  1. Surface modification of polymeric materials by cold atmospheric plasma jet

    NASA Astrophysics Data System (ADS)

    Kostov, K. G.; Nishime, T. M. C.; Castro, A. H. R.; Toth, A.; Hein, L. R. O.

    2014-09-01

    In this work we report the surface modification of different engineering polymers, such as, polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) by an atmospheric pressure plasma jet (APPJ). It was operated with Ar gas using 10 kV, 37 kHz, sine wave as an excitation source. The aim of this study is to determine the optimal treatment conditions and also to compare the polymer surface modification induced by plasma jet with the one obtained by another atmospheric pressure plasma source - the dielectric barrier discharge (DBD). The samples were exposed to the plasma jet effluent using a scanning procedure, which allowed achieving a uniform surface modification. The wettability assessments of all polymers reveal that the treatment leads to reduction of more than 40° in the water contact angle (WCA). Changes in surface composition and chemical bonding were analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-Transformed Infrared spectroscopy (FTIR) that both detected incorporation of oxygen-related functional groups. Surface morphology of polymer samples was investigated by Atomic Force Microscopy (AFM) and an increase of polymer roughness after the APPJ treatment was found. The plasma-treated polymers exhibited hydrophobic recovery expressed in reduction of the O-content of the surface upon rinsing with water. This process was caused by the dissolution of low molecular weight oxidized materials (LMWOMs) formed on the surface as a result of the plasma exposure.

  2. The Interior Analysis and 3-D Reconstruction of Internally-Mixed Light-Absorbing Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Conny, J. M.; Collins, S. M.; Anderson, I.; Herzing, A.

    2010-12-01

    Carbon-containing atmospheric particles may either absorb solar or outgoing long-wave radiation or scatter solar radiation, and thus, affect Earth’s radiative balance in multiple ways. Light-absorbing carbon that is common in urban air particles such as industrial coke dust, road dust, and diesel soot, often exists in the same particle with other phases that contain, for example, aluminum, calcium, iron, and sulfur. While the optical properties of atmospheric particles in general depend on overall particle size and shape, the inhomogeneity of chemical phases within internally-mixed particles may also greatly affect particle optical properties. In this study, a series of microscopic approaches were used to identify individual light-absorbing coarse-mode particles and to assess their interior structure and composition. Particle samples were collected in 2004 from one of the U.S. EPA’s Los Angeles Particulate Matter Supersites, and were likely affected substantially by road dust and construction dust. First, bright-field and dark-field light microscopy and computer-controlled scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDX) were used to distinguish predominantly light-absorbing carbonaceous particles from other particle types such as mineral dust, sea salt, and brake wear. Second, high-resolution SEM-EDX elemental mapping of individual carbonaceous particles was used to select particles with additional elemental phases that exhibited spatial inhomogeneity. Third, focused ion-beam SEM (FIB-SEM) with EDX was used to slice through selected particles to expose interior surfaces and to determine the spatial distribution of element phases throughout the particles. Fourth, study of the interior phases of a particle was augmented by the transmission electron microscopy (TEM) of a thin section of the particle prepared by FIB-SEM. Here, electron energy loss spectroscopy with TEM was used to study chemical bonding in the carbonaceous phase. Finally, automated serial slicing and imaging in the FIB-SEM generated a stack of secondary electron images of the particles’ interior surfaces that allowed for the 3-D reconstruction of the particles, a process known as FIB tomography. Interior surface of light-absorbing carbonaceous particle from FIB-SEM analysis.

  3. The dynamics of atmospheric dust particles in aircraft auxiliary power radial inflow turbines

    NASA Technical Reports Server (NTRS)

    Clevenger, W. B., Jr.; Tabakoff, W.

    1975-01-01

    The results of analytical and experimental studies of the trajectories that atmospheric dust particles follow as they move through a radial inflow turbine are presented. The study reveals the nature of the impacts that occur within the turbine and indicates which surfaces are expected to experience the most severe erosion. In addition, a dimensionless parameter is derived which can be used during preliminary design analysis to indicate the sizes of the particles that will be most damaging to the turbine.

  4. Atmospheric fate of oil matter adsorbed on sea salt particles under UV light

    NASA Astrophysics Data System (ADS)

    Vaitilingom, M.; Avij, P.; Huang, H.; Valsaraj, K. T.

    2014-12-01

    The presence of liquid petroleum hydrocarbons at the sea water surface is an important source of marine pollution. An oil spill in sea-water will most likely occur due to an involuntary accident from tankers, offshore platforms, etc. However, a large amount of oil is also deliberately spilled in sea-water during the clean-out process of tank vessels (e.g. for the Mediterranean Sea, 490,000 tons/yr). Moreover, the pollution caused by an oil spill does not only affect the aquatic environment but also is of concern for the atmospheric environment. A portion of the oil matter present at the sea-water surface is transported into the atmosphere viaevaporation and adsorption at the surface of sea spray particles. Few studies are related to the presence of oil matter in airborne particles resulting from their adsorption on sea salt aerosols. We observed that the non-volatile oil matter was adsorbed at the surface of sea-salt crystals (av. size of 1.1 μm). Due to their small size, these particles can have a significant residence time in the atmosphere. The hydrocarbon matter adsorbed at the surface of these particles can also be transformed by catalyzers present in the atmosphere (i.e. UV, OH, O3, ...). In this work, we focused on the photo-oxidation rates of the C16 to C30alkanes present in these particles. We utilized a bubble column reactor, which produced an abundance of small sized bubbles. These bubbles generated droplets upon bursting at the air-salt water interface. These droplets were then further dried up and lifted to the top of the column where they were collected as particles. These particles were incubated in a controlled reactor in either dark conditions or under UV-visible light. The difference of alkane content analyzed by GC-MS between the particles exposed to UV or the particles not exposed to UV indicated that up to 20% in mass was lost after 20 min of light exposure. The degradation kinetics varied for each range of alkanes (C16-20, C21-25, C26-30) from 20 to 60 μg L-1 min-1. To observe the effect on air composition when samples are exposed to solar light, experiments were conducted under controlled atmospheric conditions: oxygen free or with O3 gas. The results showed the importance of the photo-transformation processes of oil in airborne particles and its relation to the gaseous nature of the ambient atmosphere.

  5. Concentration and Gas-particle Partitioning of Atmospheric Polycyclic Aromatic Hydrocarbons in Relation to Monsoons

    NASA Astrophysics Data System (ADS)

    Ko, F. C.; Cheng, J. O.; Lee, C. L.

    2014-12-01

    The atmospheric concentrations and gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs) were determined in the Hengchun Peninsula of southern Taiwan. The concentrations of total suspended particle (TSP) and total PAH (t-PAH; gas + particulate) ranged from 1.6 to 78.8 ?g m-3 and 430 to 4400 pg m-3, respectively. The highest levels of t-PAH concentrations and particle-associated PAHs were found during the northeast (NE) monsoon season. Long-range transport and rainfall scavenging mechanisms could contribute to seasonal variations in TSP and t-PAH concentrations. Results from principal component analysis (PCA) indicated that air mass movement caused by the monsoon system was the main influence on atmospheric PAHs profiles and concentrations. Gas-particle partition coefficients (Kp) of PAHs were well-correlated with the sub-cooled liquid vapor pressures (PoL), suggesting that the gas-particle partition of PAHs follows the characteristic of PAHs. In addition, the partitioning of PAHs between gas and particle phases varied significantly between NE and SW monsoon seasons. This study sheds lights on the role of Asian monsoon regarding atmospheric transport of PAHs.

  6. Field-responsive smart composite particle suspension: materials and rheology

    NASA Astrophysics Data System (ADS)

    Zhang, Wen Ling; Liu, Ying Dan; Choi, Hyoung Jin

    2012-09-01

    Both electrorheological (ER) and magnetorheological (MR) fluids are known to be smart materials which can be rapidly and reversibly transformed from a fluid-like to a solid-like state within milliseconds by showing dramatic and tunable changes in their rheological properties under external electrical or magnetic field strength, respectively. Here, among various smart composite particles studied, recently developed core-shell structured polystyrene/graphene oxide composite based ER material as well as the dual-step functionally coated carbonyl iron composite based MR material are briefly reviewed along with their rheological characteristics under external fields.

  7. Physicochemical Properties of 'Particle Brush'-Based Materials: Using Polymer Graft Modification to Tailor Particle Interactions

    NASA Astrophysics Data System (ADS)

    Schmitt, Michael D.

    The advent of surface-initiated controlled radical polymerization techniques has allowed a new class of hybrid polymer-grafted nanoparticles, known as eparticle brushes,f to be realized. By grafting polymers from the surface, interactions between particles can be tuned using the precise control over graft architecture (i.e. chain length, dispersity, particle size, and grafting density) afforded by controlled radical polymerizations. Previously, a transition from particle-like to polymer-like interactions in small particles with increasing graft length has been observed. In the limit of long graft lengths, the polymer chains impart new interactions between particles, such as entanglements. These results outline a rich, but largely unexplored parameter space. The present thesis further elucidates the extent to which polymer graft modification facilitates new interaction types between particles and the dependence of those interactions on chain conformation. Specifically, the mechanical properties, processability, phase separation, and vibrational modes of particle brushes are examined. A dependence of the mechanical properties of particle brush assemblies on particle size is accurately captured by accounting for differences in chain conformation between particles of different sizes using a simple scaling model. Further tailoring of mechanical characteristics in weak particle brush assemblies can be achieved using appropriate homopolymer additives to form two-component systems. Improved mechanical properties are accompanied by a significant enhancement in particle processability that allows application of previously unusable processing methods. Considering more complex systems, mesoscale phase separation of nanoparticles is demonstrated for the first time by blending of particle brushes with different graft polymers. Polymer graft modification is seen to not only strengthen and introduce new interactions, but also tune particle properties. Vibrational modes of particles are softened using graft modification with the chemical confinement of surface-grafted chains inducing tunable hybridization gaps in solid assemblies fabricated by facile methods. Particle brushes offer a unique opportunity to form complex, functional material systems from simple building blocks that demonstrate a range of unique, tunable properties pertinent to applications from optical computing to phononics and lighting.

  8. Single particle measurements of material line stretching in turbulence: Experiments

    NASA Astrophysics Data System (ADS)

    Kramel, Stefan; Tympel, Saskia; Toschi, Federico; Voth, Greg

    2015-11-01

    We find that particles in the shape of chiral dipoles display a preferential rotation direction in three dimensional isotropic turbulence. The particles consist of two helical ends with opposite chirality that are connected by a straight rod. They are fabricated using 3D printing and have an aspect ratio of 10 and a length in the inertial range of our flow between oscillating grids. Due to their high aspect ratio, they move like material lines. Because material lines align with the extentional eigenvectors of the velocity gradient tensor they experience a mean stretching in turbulence. The stretching of a chiral dipole produces a rotation about the dipole axis and so chiral dipoles experience a non-zero mean spinning rate in turbulence. These results provide a first direct experimental measurement of the rate of material line stretching in turbulence.

  9. Identification of the typical metal particles among haze, fog, and clear episodes in the Beijing atmosphere.

    PubMed

    Hu, Yunjie; Lin, Jun; Zhang, Suanqin; Kong, Lingdong; Fu, Hongbo; Chen, Jianmin

    2015-04-01

    For a better understanding of metal particle morphology and behaviors in China, atmospheric aerosols were sampled in the summer of 2012 in Beijing. The single-particle analysis shows various metal-bearing speciations, dominated by oxides, sulfates and nitrates. A large fraction of particles is soluble. Sources of Fe-bearing particles are mainly steel industries and oil fuel combustion, whereas Zn- and Pb-bearing particles are primarily contributed by waste incineration, besides industrial combustion. Other trace metal particles play a minor rule, and may come from diverse origins. Mineral dust and anthropogenic source like vehicles and construction activities are of less importance to metal-rich particles. Statistics of 1173 analyzed particles show that Fe-rich particles (48.5%) dominate the metal particles, followed by Zn-rich particles (34.9%) and Pb-rich particles (15.6%). Compared with the abundances among clear, haze and fog conditions, a severe metal pollution is identified in haze and fog episodes. Particle composition and elemental correlation suggest that the haze episodes are affected by the biomass burning in the southern regions, and the fog episodes by the local emission with manifold particle speciation. Our results show the heterogeneous reaction accelerated in the fog and haze episodes indicated by more zinc nitrate or zinc sulfate instead of zinc oxide or carbonate. Such information is useful in improving our knowledge of fine airborne metal particles on their morphology, speciation, and solubility, all of which will help the government introduce certain control to alleviate metal pollution. PMID:25555257

  10. Reactor for producing large particles of materials from gases

    NASA Technical Reports Server (NTRS)

    Flagan, Richard C. (Inventor); Alam, Mohammed K. (Inventor)

    1987-01-01

    A method and apparatus is disclosed for producing large particles of material from gas, or gases, containing the material (e.g., silicon from silane) in a free-space reactor comprised of a tube (20) and controlled furnace (25). A hot gas is introduced in the center of the reactant gas through a nozzle (23) to heat a quantity of the reactant gas, or gases, to produce a controlled concentration of seed particles (24) which are entrained in the flow of reactant gas, or gases. The temperature profile (FIG. 4) of the furnace is controlled for such a slow, controlled rate of reaction that virtually all of the material released condenses on seed particles and new particles are not nucleated in the furnace. A separate reactor comprised of a tube (33) and furnace (30) may be used to form a seed aerosol which, after passing through a cooling section (34) is introduced in the main reactor tube (34) which includes a mixer (36) to mix the seed aerosol in a controlled concentration with the reactant gas or gases.

  11. Fine particle receptor modeling in the atmosphere of Mexico City.

    PubMed

    Vega, Elizabeth; Lowenthal, Douglas; Ruiz, Hugo; Reyes, Elizabeth; Watson, John G; Chow, Judith C; Viana, Mar; Querol, Xavier; Alastuey, Andrés

    2009-12-01

    Source apportionment analyses were carried out by means of receptor modeling techniques to determine the contribution of major fine particulate matter (PM2.5) sources found at six sites in Mexico City. Thirty-six source profiles were determined within Mexico City to establish the fingerprints of particulate matter sources. Additionally, the profiles under the same source category were averaged using cluster analysis and the fingerprints of 10 sources were included. Before application of the chemical mass balance (CMB), several tests were carried out to determine the best combination of source profiles and species used for the fitting. CMB results showed significant spatial variations in source contributions among the six sites that are influenced by local soil types and land use. On average, 24-hr PM2.5 concentrations were dominated by mobile source emissions (45%), followed by secondary inorganic aerosols (16%) and geological material (17%). Industrial emissions representing oil combustion and incineration contributed less than 5%, and their contribution was higher at the industrial areas of Tlalnepantla (11%) and Xalostoc (8%). Other sources such as cooking, biomass burning, and oil fuel combustion were identified at lower levels. A second receptor model (principal component analysis, [PCA]) was subsequently applied to three of the monitoring sites for comparison purposes. Although differences were obtained between source contributions, results evidence the advantages of the combined use of different receptor modeling techniques for source apportionment, given the complementary nature of their results. Further research is needed in this direction to reach a better agreement between the estimated source contributions to the particulate matter mass. PMID:20066907

  12. Morphology and Chemical composition of Atmospheric Particles over Semi-Arid region (Jaipur, Rajasthan) of India

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Agnihotri, R.; Yadav, P.; Singh, S.; Tawale, J. S.; Rashmi, R.; Prasad, M.; Arya, B. C.; Mishra, N.

    2012-12-01

    Uncertainties associated with the radiative forcing of atmospheric dust particles is highest, owing to lack of region-specific dust morphology (particle shape, size) and mineralogy (chemical composition) database, needed for modeling their optical properties (Mishra and Tripathi, 2008). To fill this gap for the Indian region, we collected atmospheric particles (with aerodynamic size <5um, PM5 and a few bulk particles; TSP) from seven sites of Jaipur and nearby locales (semi-arid region, in the vicinity of Thar Desert of Rajasthan) at varying altitude, during late winters of ca. 2012. PM5 particles were collected on Teflon filters (for bulk chemical analyses), while pure Tin substrates (~1×1 mm2) were used for investigating individual particle morphology. Using Scanning Electron Microscope equipped with Energy Dispersive X ray (SEM-EDX) facility at NPL, images of individual particles were recorded and the morphological parameters (e.g. Aspect ratio; AR, Circulatory parameter; CIR.) were retrieved following Okada et al. (2001), whereas chemical compositions of individual particles were determined by EDX and bulk samples by X ray fluorescence (XRF). The geometrical size distributions of atmospheric particles were generated for each site. Based on NIST (National Institute of Standard and Technology, USA) morphology database, the site-specific individual particle shapes reveal predominance of "Layered" (calcite and quartz rich), "Angular" structures (quartz rich) and "Flattened" particles over all the sites. Particles were found to be highly non-spherical with irregular shapes (CIR varying from 1 to 0.22 with median value ~0.76; AR varying from 1 to 5.4 with median value ~1.64). Noteworthy to mention, that unit values of AR and CIR represent spherical particles. Chemical analyses of PM5 particles revealed dominance of crustal elements e.g. Si, Al, Fe, Ca, Mg, in general. Particles over Kukas Hill (27.027° N, 75.919° E; ~800 MAGL) showed highest Fe mass fractions (~43%), i.e. a key element (in form of hematite; Fe2O3) for solar (visible) energy absorption and thus heating the atmosphere. The retrieved morphological parameters help to construct particle shape and number size distribution that are highly useful to reduce the uncertainty in radiative forcing of dust particles appreciably when combined with particle chemical composition as suggested by Kalashnikova and Sokolik (2004). References : Mishra, S. K., and S. N. Tripathi (2008), Modeling optical properties of mineral dust over the Indian Desert, J. Geophys. Res., 113, D23201, 19 PP., doi:10.1029/2008JD010048. Okada, K., J. Heintzenberg, K. Kai, and Y. Qin (2001), Shape of atmospheric mineral particles collected in three Chinese arid-regions, Geophys. Res. Lett., 28, 3123-3126 Kalashnikova OV, Sokolik IN. (2004) Modeling the radiative properties of nonspherical soil-derived mineral aerosols, J Quant Spectrosc Radiat Transfer, 87, 137-66.

  13. Seasonality of the chemistry in atmospheric new particle formation in southern Africa

    NASA Astrophysics Data System (ADS)

    Vakkari, Ville; Tiitta, Petri; Beukes, Johan P.; van Zyl, Pieter G.; Josipovic, Miroslav; Venter, Andrew D.; Jaars, Kerneels; Worsnop, Douglas R.; Kulmala, Markku; Laakso, Lauri

    2014-05-01

    Atmospheric new particle formation has been observed in various different environments ranging from remote background regions to polluted megacities. In many environments it has also been shown to increase the concentration of particles in sizes that can act as cloud condensation nuclei and therefore affect the climate. New particle formation is essentially a two-step process, where the first step is nucleation in the nanometer size range, which is followed by a growth phase to climatically relevant sizes. While recent advances in experimental methods have enabled direct observations of atmospheric nucleation, aerosol particle chemistry during the growth phase following nucleation has been characterised in relatively few studies and never covered a full seasonal cycle. In this study we utilized one year of continuous online chemical composition measurements of submicron aerosol particles with an Aerosol Chemical Speciation Monitor (ACSM) together with concurrent size distribution measurements from 12 to 840 nm with a Differential Mobility Particle Sizer (DMPS). The measurements were carried out at Welgegund measurement station in South Africa, which is approximately 100 km west of Johannesburg from September 2010 to August 2011. During this period the frequency of new particle formation events was 78 % with 90 % data coverage. The high frequency of new particle formation events enabled us to study the chemistry of aerosol particle growth in 89 new particle formation events during the one year period. Organic aerosol and sulphate were the dominant constituents in the growth of newly formed particles at Welgegund. On average, organic aerosol constituted 49 % of the growth and sulphate 36 %. However, the ratio of organic aerosol and sulphate varied widely depending on whether the air masses originated in the clean sector or in the anthropogenic sector. Ammonium correlated with sulphate (correlation coefficient 0.83) and constituted on average 11 % of the growth, while nitrate was a minor constituent with a 4 % average fraction. We observed a clear seasonal pattern in the organic aerosol source rate with the highest values occurring during the local spring and summer.

  14. Search for Fractional-Charge Particles in Meteoritic Material

    SciTech Connect

    Kim, Peter C.; Lee, Eric R.; Lee, Irwin T.; Perl, Martin L.; Halyo, Valerie; Loomba, Dinesh

    2007-10-19

    We have used an automated Millikan oil drop method to search for free fractional-charge particles in a sample containing in total 3.9 mg of pulverized Allende meteorite suspended in 259 mg of mineral oil. The average diameter of the drops was 26.5 {mu}m with the charge on about 42 500 000 drops being measured. This search was motivated by the speculation that isolatable, fractional-charge particles produced in the early Universe and present in our Solar System are more likely to be accumulated in asteroids than on Earth's surface. No evidence for fractional-charge particles was found. With 95% confidence, the concentration of particles with fractional-charge more than 0.25 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 1.3x10{sup -21} particles per nucleon in the meteoritic material and less than 1.9x10{sup -23} particles per nucleon in the mineral oil.

  15. Optical characterization of solid particle solar central receiver materials

    SciTech Connect

    Stahl, K.A.; Griffin, J.W.; Matson, B.S.; Pettit, R.B.

    1986-05-01

    The angular scattering properties and scattering and absorption components of the extinction coefficient have been measured for Master Beads, an iron-doped Al/sub 2/O/sub 3/ spheroid manufactured by Norton Chemical Co., Worcester, MA. This material, commonly used as a proppant in oil well drilling operations, exhibits good optical absorption properties over the solar insolation spectrum, and favorable thermal and mechanical properties for temperatures up to 1000/sup 0/C. These characteristics, along with its low cost, make Master Beads a good candidate as the absorbing medium in the solid particle solar central receiver concept. The objective of the ongoing optical properties measurement program is to obtain information to be used as input to radiation transfer models for prediction of receiver performance. Scattering and extinction measurements were performed at 632.8 nm in a falling curtain geometry of one-particle nominal thickness. Measurements were performed over a range of mass flow rates and particle densities. Photographic documentation of curtain particle density enabled calculation of mean scattering and absorption loss components per particle in the absence of multiple-particle optical interactions.

  16. [Size distribution properties of atmospheric aerosol particles during summer and autumn in Lanzhou].

    PubMed

    Zhao, Su-Ping; Yu, Ye; Chen, Jin-Bei; Liu, N; He, Jian-Jun

    2012-03-01

    Atmospheric particle size distributions (size range 0.5-20 microm) were measured using aerodynamic particle sizer (APS-3321) from August 1st to October 31st in Lanzhou. Variations of particle concentrations and properties of volume concentration distributions were analyzed through cluster analysis. The main objective of this study was to identify factors affecting the particle size distributions in Lanzhou. The hourly averaged particle number, surface area and volume concentrations are (108.1 +/- 92.2) cm(-3), (282.9 +/- 267.9) microm2 x cm(-3) and (92.2 +/- 127.3) microm3 x cm(-3), respectively. The number, surface area and volume concentrations of fine particles (0.5-2.5 microm) account for 98.7%, 73.8% and 52.9% of the total particle concentrations in 0.5-20 microm, respectively. The size distribution of number concentrations is unimodal with a peak at accumulation mode. The size distributions of surface area and volume concentrations are bimodal with peaks at accumulation mode and coarse mode, respectively. The size distributions of particle volume concentrations mainly have 7 clusters, indicating the effect of different sources and meteorological conditions. Coarse mode particles are dominant in particle volume size distributions affected by wind-borne dust and on dust days, while that affected by motor vehicle combustion emissions and traffic resuspended dust are characterized by bimodal with peaks at accumulation mode and coarse mode, respectively. PMID:22624356

  17. The effect of particles and electromagnetic waves on vortex structures in the atmosphere and the ionosphere

    NASA Astrophysics Data System (ADS)

    Izhovkina, N. I.

    2015-05-01

    The formation of vortex structures in an inhomogeneous gyrotropic atmosphere was stochastically determined. Atmospheric gyrotropy is induced by the Coriolis force acting as the Earth rotates and the motion of charged particles in the geomagnetic field. Vortices of a plasma nature are observed in the atmosphere. The electric field of such plasma vortices originates within the fields of pressure gradients of a mosaic cell topology upon the ionization of particles. It is shown that waves in a neutral atmosphere, electric fields, and electromagnetic waves affect the stability of vortex structures. Wave signals from anthropogenic sources and smog may stimulate local precipitation upon the passage of a cloud front and weaken or strengthen vortex structures. The plasma vortex may capture charged particles of different masses. The charge separation in plasma vortex structures is driven by the polarization drift at the decay of electric fields. The self-focusing of plasma vortices upon the condensation of moisture in the atmospheric cloud cover leads to an increase in the energy of vortices.

  18. Large-eddy simulation of particle-laden atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Ilie, Marcel; Smith, Stefan Llewellyn

    2008-11-01

    Pollen dispersion in the atmospheric boundary layer (ABL) is numerically investigated using a hybrid large-eddy simulation (LES) Lagrangian approach. Interest in prediction of pollen dispersion stems from two reasons, the allergens in the pollen grains and increasing genetic manipulation of plants leading to the problem of cross pollination. An efficient Eulerian-Lagrangian particle dispersion algorithm for the prediction of pollen dispersion in the atmospheric boundary layer is outlined. The volume fraction of the dispersed phase is assumed to be small enough such that particle-particle collisions are negligible and properties of the carrier flow are not modified. Only the effect of turbulence on particle motion has to be taken into account (one-way coupling). Hence the continuous phase can be treated separate from the particulate phase. The continuous phase is determined by LES in the Eulerian frame of reference whereas the dispersed phase is simulated in a Lagrangian frame of reference. Numerical investigations are conducted for the convective, neutral and stable boundary layer as well different topographies. The results of the present study indicate that particles with small diameter size follow the flow streamlines, behaving as tracers, while particles with large diameter size tend to follow trajectories which are independent of the flow streamlines. Particles of ellipsoidal shape travel faster than the ones of spherical shape.

  19. Single particle size and fluorescence spectra from emissions of burning materials in a tube furnace to simulate burn pits

    NASA Astrophysics Data System (ADS)

    Pan, Yong-Le; Houck, Joshua D. T.; Clark, Pamela A.; Pinnick, Ronald G.

    2013-08-01

    A single-particle fluorescence spectrometer (SPFS) and an aerodynamic particle sizer were used to measure the fluorescence spectra and particle size distribution from the particulate emissions of 12 different burning materials in a tube furnace to simulate open-air burning of garbage. Although the particulate emissions are likely dominated by particles <1 μm diameter, only the spectra of supermicron particles were measured here. The overall fluorescence spectral profiles exhibit either one or two broad bands peaked around 300-450 nm within the 280-650 nm spectral range, when the particles are illuminated with a 263-nm laser. Different burning materials have different profiles, some of them (cigarette, hair, uniform, paper, and plastics) show small changes during the burning process, and while others (beef, bread, carrot, Styrofoam, and wood) show big variations, which initially exhibit a single UV peak (around 310-340 nm) and a long shoulder in visible, and then gradually evolve into a bimodal spectrum with another visible peak (around 430-450 nm) having increasing intensity during the burning process. These spectral profiles could mainly derive from polycyclic aromatic hydrocarbons with the combinations of tyrosine-like, tryptophan-like, and other humic-like substances. About 68 % of these single-particle fluorescence spectra can be grouped into 10 clustered spectral templates that are derived from the spectra of millions of atmospheric aerosol particles observed in three locations; while the others, particularly these bimodal spectra, do not fall into any of the 10 templates. Therefore, the spectra from particulate emissions of burning materials can be easily discriminated from that of common atmospheric aerosol particles. The SFFS technology could be a good tool for monitoring burning pit emissions and possibly for distinguishing them from atmospheric aerosol particles.

  20. Aqueous Processing of Atmospheric Organic Particles in Cloud Water Collected via Aircraft Sampling.

    PubMed

    Boone, Eric J; Laskin, Alexander; Laskin, Julia; Wirth, Christopher; Shepson, Paul B; Stirm, Brian H; Pratt, Kerri A

    2015-07-21

    Cloudwater and below-cloud atmospheric particle samples were collected onboard a research aircraft during the Southern Oxidant and Aerosol Study (SOAS) over a forested region of Alabama in June 2013. The organic molecular composition of the samples was studied to gain insights into the aqueous-phase processing of organic compounds within cloud droplets. High resolution mass spectrometry (HRMS) with nanospray desorption electrospray ionization (nano-DESI) and direct infusion electrospray ionization (ESI) were utilized to compare the organic composition of the particle and cloudwater samples, respectively. Isoprene and monoterpene-derived organosulfates and oligomers were identified in both the particles and cloudwater, showing the significant influence of biogenic volatile organic compound oxidation above the forested region. While the average O:C ratios of the organic compounds were similar between the atmospheric particle and cloudwater samples, the chemical composition of these samples was quite different. Specifically, hydrolysis of organosulfates and formation of nitrogen-containing compounds were observed for the cloudwater when compared to the atmospheric particle samples, demonstrating that cloud processing changes the composition of organic aerosol. PMID:26068538

  1. Aqueous Processing of Atmospheric Organic Particles in Cloud Water Collected via Aircraft Sampling

    SciTech Connect

    Boone, Eric J.; Laskin, Alexander; Laskin, Julia; Wirth, Christopher; Shepson, Paul B.; Stirm, Brian H.; Pratt, Kerri A.

    2015-07-21

    Cloud water and below-cloud atmospheric particle samples were collected onboard a research aircraft during the Southern Oxidant and Aerosol Study (SOAS) over a forested region of Alabama in June 2013. The organic molecular composition of the samples was studied to gain insights into the aqueous-phase processing of organic compounds within cloud droplets. High resolution mass spectrometry with nanospray desorption electrospray ionization and direct infusion electrospray ionization were utilized to compare the organic composition of the particle and cloud water samples, respectively. Isoprene and monoterpene-derived organosulfates and oligomers were identified in both the particles and cloud water, showing the significant influence of biogenic volatile organic compound oxidation above the forested region. While the average O:C ratios of the organic compounds were similar between the atmospheric particle and cloud water samples, the chemical composition of these samples was quite different. Specifically, hydrolysis of organosulfates and formation of nitrogen-containing compounds were observed for the cloud water when compared to the atmospheric particle samples, demonstrating that cloud processing changes the composition of organic aerosol.

  2. Relating atmospheric and oceanic DMS levels to particle nucleation events in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Chang, Rachel Y.-W.; Sjostedt, Steven J.; Pierce, Jeffrey R.; Papakyriakou, Tim N.; Scarratt, Michael G.; Michaud, Sonia; Levasseur, Maurice; Leaitch, W. Richard; Abbatt, Jonathan P. D.

    2011-09-01

    Measurements of ocean surface and atmospheric dimethyl sulfide (DMS) and particle size distributions were made in the Canadian Arctic Archipelago during the fall of 2007 and the late summer of 2008 aboard the Canadian Coast Guard Ship Amundsen. Nucleation-mode particles were observed during the 2008 cruise, which took place in the eastern Arctic from August to September when the atmosphere and ocean were more photo-active as compared to the October 2007 transit in the Beaufort Sea during which no nucleation/growth events were observed. The observed nucleation periods in 2008 coincided with high atmospheric and ocean surface DMS concentrations, suggesting that the particles originated from marine biogenic sources. An aerosol microphysics box model was used to simulate nucleation given the measured conditions in the marine boundary layer. Although other sources may have contributed, we find that the newly formed particles can be accounted for by a marine biogenic DMS source for combinations of the following parameters: [OH] ≥ 3 × 105 molecules cm-3, DMS mixing ratio is ≥ 100 pptv, the activation coefficient is ≤ 10-7 and the background particle concentration is ≤ 100 cm-3.

  3. Topical Issue on Optical Particle Characterization and Remote Sensing of the Atmosphere: Part II

    NASA Technical Reports Server (NTRS)

    Videen, Gorden; Sun, Wenbo; Kocifaj, Miroslav; Kai, Kenji; Kawamoto, Kazuaki; Horvath, Helmuth; Mishchenko, Michael

    2015-01-01

    This represents the second topical issue on optical particle characterization and remote sensing. These two issues resulted from recent interest in increasing our understanding of the Earth-atmosphere system that has been a scientific and political priority for the last few decades. While the initial issue had a stronger focus on microphysics and its implications to the Earth-atmosphere system, this issue is more applied, with a heavier weighting on remote-sensing aspects, atmospheric information retrieval. The first issue was roughly divided into studies that focused on observations of aerosols, associated properties of aerosols and their effects on light-scattering, retrievals of aerosol properties and novel applications.This topical issue is the second of two parts. Within this issue we analyze different aspects of the problem of atmospheric characterization and present a broad overview of the topical area, with a focus especially on lidar measurements and information retrieval. Research includes the development of new observational techniques, theory, experiment and atmospheric characterizations ranging from fundamental microphysical properties of individual aerosol particles to broad characterizations of the entire atmosphere.

  4. Nonlinear acoustic-gravity waves and dust particle redistribution in earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Izvekova, Yu. N.; Popel, S. I.; Chen, B. B.

    2015-11-01

    A continuously stratified model of nonadiabatic terrestrial atmosphere with taking into account the temperature profile is developed to study a possibility of instability development of acoustic-gravity (AG-) waves. It is shown that the existence of the regions in the atmosphere where the instability conditions are satisfied is due to the cooperation of thermal flow of solar radiation, infrared emission of the atmosphere, water vapor condensation, as well as thermal conductivity. Large-amplitude vortices in Earth's troposphere and ionosphere and their possible structure as well as redistribution of dust particles in the ionosphere as a result of vortical motions are discussed. The following possibilities for the dust particle redistribution are studied: capture and evolution of dust particles in AG-vortices, formation of dust vortices as a result of involving a great number of dust particles into vortex motions, and formation of vertical and horizontal dust flows (streamers and zonal flows). It is shown that excitation of AG-vortices at the ionospheric altitudes as a result of development of AG-wave instability leads to a substantial transportation of dust particles and their mixing. Layers of dust particles with a thickness of about a kilometer, forming at the altitudes less than 120 km, distribute within the region of the existence of AG-vortical structures. As a result, at altitudes of 110-120 km, dust vortices can appear, and transportation of particles up to altitudes of 130 km becomes possible. One of the ways of transportation of dust particles in the ionosphere is dust flows, which are generated by dust vortices as a result of development of parametric instability.

  5. Single particle measurements of material line stretching in turbulence: Numerics

    NASA Astrophysics Data System (ADS)

    Tympel, Saskia; Kramel, Stefan; Toschi, Federico; Voth, Greg; University of Technology Eindhoven Team; Wesleyan University Collaboration

    2015-11-01

    In three dimensional isotropic turbulence, particles in the shape of chiral dipoles display a preferential rotation direction. Chiral dipoles have two helical ends with opposite chirality that are connected by a straight rod. We assume particles to be small and neutrally buoyant, so that their centre of mass follows the same trajectories of tracer particles in homogeneous isotropic turbulence. First, we tune the model for dipoles spinning dynamics via Stokesian Dynamics simulations. Then, we compute the spinning dynamics around their preferential rotation axis in homogenous and isotropic turbulence using turbulent fields from high resolution DNS. Our numerics shows a very good agreement with experimental results and allow a deeper insight into the mechanisms of material line stretching in turbulence.

  6. The effect of precipitating particles on middle atmospheric night time ozone during enhanced geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Daae, M.; Espy, P. J.; Newnham, D.; Kleinknecht, N.; Clilverd, M.

    2010-12-01

    We have investigated the effect of precipitating particles on middle atmospheric ozone during a moderate geomagnetic storm in July 2009. It is expected that the number of precipitating particles increases with increasing geomagnetic activity, and that these precipitated particles will subsequently enhance the production of nitrosonium (NO+) and odd hydrogen (HOx) in the upper atmosphere. The lifetime of HOx and its associated ozone (O3) destruction is short, whilst NO+ can form long-lived odd nitrogen during times of high geomagnetic activity, (NOx), which can affect ozone over a longer time span, and hence a wider spatial range due to transport. We use the National Oceanic and Atmospheric Administration (NOAA) satellite data to identify and analyze the particles that precipitated over Antarctica during the moderate geomagnetic storm. To analyze the subsequent nitric oxide (NO) enhancement and O3 depletion we use a microwave radiometer stationed at Troll, Antarctica (72°S, 2.5°E, L=4.76). This microwave radiometer operating at 250 GHz gives high temporal and vertical resolution of the NO and O3 column. The Atmospheric Radiation Transfer Simulator (ARTS) and QPack have been employed to perform the inversions of the spectra. During the July storm that reached -79 nT on the Dst index, we observe radiation-belt particle precipitation over Troll, an NO increase, and a direct O3 depletion of 30% between 60 and 80 km altitude. This O3 depletion lasted for 9 days, and its centroid descended to 55 km altitude at a vertical velocity of 1-3 m/s. This work shows that moderate storms, which are common-place and occur even during solar minimum, can cause a significant and direct effect in the middle atmospheric ozone distribution.

  7. Synthesis of Nanocrystalline Iron Oxide Particles by Microwave Plasma Jet at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Li, Shou-Zhe; Hong, Y. C.; Uhm, Han. S.; Li, Zhe-Kui

    2004-11-01

    Nanocrystalline iron oxide particles have been prepared in gas phase at atmospheric pressure by employing a microwave plasma jet. The vaporized iron pentacarbonyl (Fe(CO)5) carried by argon gas is pyrolyzed in the oxygen plasma generated by a microwave plasma jet. Fe2O3 powder with an average particle size of 26 nm is synthesized, which is identified and characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and scanning electron microscopy (SEM). It is shown that operating the microwave plasma jet in the continuous flow mode at atmosphere is promising for the mass production of nanosized metal oxide powders other than nanocrystalline iron oxide particles, economically and efficiently.

  8. Viscosity of α-pinene secondary organic material and implications for particle growth and reactivity

    PubMed Central

    Renbaum-Wolff, Lindsay; Grayson, James W.; Bateman, Adam P.; Kuwata, Mikinori; Sellier, Mathieu; Murray, Benjamin J.; Shilling, John E.; Martin, Scot T.; Bertram, Allan K.

    2013-01-01

    Particles composed of secondary organic material (SOM) are abundant in the lower troposphere. The viscosity of these particles is a fundamental property that is presently poorly quantified yet required for accurate modeling of their formation, growth, evaporation, and environmental impacts. Using two unique techniques, namely a “bead-mobility” technique and a “poke-flow” technique, in conjunction with simulations of fluid flow, the viscosity of the water-soluble component of SOM produced by α-pinene ozonolysis is quantified for 20- to 50-μm particles at 293–295 K. The viscosity is comparable to that of honey at 90% relative humidity (RH), similar to that of peanut butter at 70% RH, and at least as viscous as bitumen at ≤30% RH, implying that the studied SOM ranges from liquid to semisolid or solid across the range of atmospheric RH. These data combined with simple calculations or previous modeling studies are used to show the following: (i) the growth of SOM by the exchange of organic molecules between gas and particle may be confined to the surface region of the particles for RH ≤ 30%; (ii) at ≤30% RH, the particle-mass concentrations of semivolatile and low-volatility organic compounds may be overpredicted by an order of magnitude if instantaneous equilibrium partitioning is assumed in the bulk of SOM particles; and (iii) the diffusivity of semireactive atmospheric oxidants such as ozone may decrease by two to five orders of magnitude for a drop in RH from 90% to 30%. These findings have possible consequences for predictions of air quality, visibility, and climate. PMID:23620520

  9. Viscosity of α-pinene secondary organic material and implications for particle growth and reactivity.

    PubMed

    Renbaum-Wolff, Lindsay; Grayson, James W; Bateman, Adam P; Kuwata, Mikinori; Sellier, Mathieu; Murray, Benjamin J; Shilling, John E; Martin, Scot T; Bertram, Allan K

    2013-05-14

    Particles composed of secondary organic material (SOM) are abundant in the lower troposphere. The viscosity of these particles is a fundamental property that is presently poorly quantified yet required for accurate modeling of their formation, growth, evaporation, and environmental impacts. Using two unique techniques, namely a "bead-mobility" technique and a "poke-flow" technique, in conjunction with simulations of fluid flow, the viscosity of the water-soluble component of SOM produced by α-pinene ozonolysis is quantified for 20- to 50-μm particles at 293-295 K. The viscosity is comparable to that of honey at 90% relative humidity (RH), similar to that of peanut butter at 70% RH, and at least as viscous as bitumen at ≤30% RH, implying that the studied SOM ranges from liquid to semisolid or solid across the range of atmospheric RH. These data combined with simple calculations or previous modeling studies are used to show the following: (i) the growth of SOM by the exchange of organic molecules between gas and particle may be confined to the surface region of the particles for RH ≤ 30%; (ii) at ≤30% RH, the particle-mass concentrations of semivolatile and low-volatility organic compounds may be overpredicted by an order of magnitude if instantaneous equilibrium partitioning is assumed in the bulk of SOM particles; and (iii) the diffusivity of semireactive atmospheric oxidants such as ozone may decrease by two to five orders of magnitude for a drop in RH from 90% to 30%. These findings have possible consequences for predictions of air quality, visibility, and climate. PMID:23620520

  10. Effect of atmospheric conditions on operation of terahertz systems for remote detection of ionizing materials

    SciTech Connect

    Nusinovich, Gregory S.; Kashyn, Dmytro G.; Tatematsu, Yoshinori; Idehara, Toshitaka

    2014-01-15

    This study was motivated by a new concept of remote detection of concealed radioactive materials by using a high power terahertz (THz) wave beam, which can be focused in a small spot where the wave electric field exceeds the breakdown threshold. In the presence of seed electrons in such a volume, this focusing can initiate the avalanche breakdown. Typically, an ambient density of free electrons is assumed to be at the level of one particle per cubic centimeter. So, when a breakdown-prone volume is smaller than 1 cm{sup 3}, there should be significant difference between the breakdown rates in the case of presence of additional sources of ionization versus its absence. Since the flux density of gamma rays emitted by radioactive materials rapidly falls with the distance from the source, while the intensity of THz waves also decreases with the distance due to wave attenuation in the atmosphere, it is important to find an optimal location of the breakdown to be initiated for a given distance between a radioactive material and a THz antenna. This problem is analyzed in a given paper with the account for not only atmospheric attenuation of THz waves but also the air turbulence.

  11. Estimating the contribution of photochemical particle formation to ultrafine particle number averages in an urban atmosphere.

    PubMed

    Ma, N; Birmili, W

    2015-04-15

    Ultrafine particles (UFPs, diameter<100 nm) have gained major attention in the environmental health discussion due to a number of suspected health effects. Observations of UFPs in urban air reveal the presence of several, time-dependent particle sources. In order to attribute measured UFP number concentrations to different source type contributions, we analyzed observations collected at a triplet of observation sites (roadside, urban background, rural) in the city of Leipzig, Germany. Photochemical new particle formation (NPF) events can be the overwhelming source of UFP particles on particular days, and were identified on the basis of characteristic patterns in the particle number size distribution data. A subsequent segmentation of the diurnal cycles of UFP concentration yielded a quantitative contribution of NPF events to daily, monthly, and annual mean values. At roadside, we obtained source contributions to the annual mean UFP number concentration (diameter range 5-100 nm) for photochemical NPF events (7%), local traffic (52%), diffuse urban sources (20%), and regional background (21%). The relative contribution of NPF events rises when moving away from roadside to the urban background and rural sites (14 and 30%, respectively). Their contribution also increases when considering only fresh UFPs (5-20 nm) (21% at the urban background site), and conversely decreases when considering UFPs at bigger sizes (20-100 nm) (8%). A seasonal analysis showed that NPF events have their greatest importance on UFP number concentration in the months May-August, accounting for roughly half of the fresh UFPs (5-20 nm) at the urban background location. The simplistic source apportionment presented here might serve to better characterize exposure to ambient UFPs in future epidemiological studies. PMID:25617781

  12. Organic and inorganic decomposition products from the thermal desorption of atmospheric particles

    NASA Astrophysics Data System (ADS)

    Williams, Brent J.; Zhang, Yaping; Zuo, Xiaochen; Martinez, Raul E.; Walker, Michael J.; Kreisberg, Nathan M.; Goldstein, Allen H.; Docherty, Kenneth S.; Jimenez, Jose L.

    2016-04-01

    Atmospheric aerosol composition is often analyzed using thermal desorption techniques to evaporate samples and deliver organic or inorganic molecules to various designs of detectors for identification and quantification. The organic aerosol (OA) fraction is composed of thousands of individual compounds, some with nitrogen- and sulfur-containing functionality and, often contains oligomeric material, much of which may be susceptible to decomposition upon heating. Here we analyze thermal decomposition products as measured by a thermal desorption aerosol gas chromatograph (TAG) capable of separating thermal decomposition products from thermally stable molecules. The TAG impacts particles onto a collection and thermal desorption (CTD) cell, and upon completion of sample collection, heats and transfers the sample in a helium flow up to 310 °C. Desorbed molecules are refocused at the head of a gas chromatography column that is held at 45 °C and any volatile decomposition products pass directly through the column and into an electron impact quadrupole mass spectrometer. Analysis of the sample introduction (thermal decomposition) period reveals contributions of NO+ (m/z 30), NO2+ (m/z 46), SO+ (m/z 48), and SO2+ (m/z 64), derived from either inorganic or organic particle-phase nitrate and sulfate. CO2+ (m/z 44) makes up a major component of the decomposition signal, along with smaller contributions from other organic components that vary with the type of aerosol contributing to the signal (e.g., m/z 53, 82 observed here for isoprene-derived secondary OA). All of these ions are important for ambient aerosol analyzed with the aerosol mass spectrometer (AMS), suggesting similarity of the thermal desorption processes in both instruments. Ambient observations of these decomposition products compared to organic, nitrate, and sulfate mass concentrations measured by an AMS reveal good correlation, with improved correlations for OA when compared to the AMS oxygenated OA (OOA) component. TAG signal found in the traditional compound elution time period reveals higher correlations with AMS hydrocarbon-like OA (HOA) combined with the fraction of OOA that is less oxygenated. Potential to quantify nitrate and sulfate aerosol mass concentrations using the TAG system is explored through analysis of ammonium sulfate and ammonium nitrate standards. While chemical standards display a linear response in the TAG system, redesorptions of the CTD cell following ambient sample analysis show some signal carryover on sulfate and organics, and new desorption methods should be developed to improve throughput. Future standards should be composed of complex organic/inorganic mixtures, similar to what is found in the atmosphere, and perhaps will more accurately account for any aerosol mixture effects on compositional quantification.

  13. Organic and inorganic decomposition products from the thermal desorption of atmospheric particles

    NASA Astrophysics Data System (ADS)

    Williams, B. J.; Zhang, Y.; Zuo, X.; Martinez, R. E.; Walker, M. J.; Kreisberg, N. M.; Goldstein, A. H.; Docherty, K. S.; Jimenez, J. L.

    2015-12-01

    Atmospheric aerosol composition is often analyzed using thermal desorption techniques to evaporate samples and deliver organic or inorganic molecules to various designs of detectors for identification and quantification. The organic aerosol (OA) fraction is composed of thousands of individual compounds, some with nitrogen- and sulfur-containing functionality, and often contains oligomeric material, much of which may be susceptible to decomposition upon heating. Here we analyze thermal decomposition products as measured by a thermal desorption aerosol gas chromatograph (TAG) capable of separating thermal decomposition products from thermally stable molecules. The TAG impacts particles onto a collection and thermal desorption (CTD) cell, and upon completion of sample collection, heats and transfers the sample in a helium flow up to 310 °C. Desorbed molecules are refocused at the head of a GC column that is held at 45 °C and any volatile decomposition products pass directly through the column and into an electron impact quadrupole mass spectrometer (MS). Analysis of the sample introduction (thermal decomposition) period reveals contributions of NO+ (m/z 30), NO2+ (m/z 46), SO+ (m/z 48), and SO2+ (m/z 64), derived from either inorganic or organic particle-phase nitrate and sulfate. CO2+ (m/z 44) makes up a major component of the decomposition signal, along with smaller contributions from other organic components that vary with the type of aerosol contributing to the signal (e.g., m/z 53, 82 observed here for isoprene-derived secondary OA). All of these ions are important for ambient aerosol analyzed with the aerosol mass spectrometer (AMS), suggesting similarity of the thermal desorption processes in both instruments. Ambient observations of these decomposition products compared to organic, nitrate, and sulfate mass concentrations measured by an AMS reveal good correlation, with improved correlations for OA when compared to the AMS oxygenated OA (OOA) component. TAG signal found in the traditional compound elution time period reveals higher correlations with AMS hydrocarbon-like OA (HOA) combined with the fraction of OOA that is less oxygenated. Potential to quantify nitrate and sulfate aerosol mass concentrations using the TAG system is explored through analysis of ammonium sulfate and ammonium nitrate standards. While chemical standards display a linear response in the TAG system, re-desorptions of the CTD cell following ambient sample analysis shows some signal carryover on sulfate and organics, and new desorption methods should be developed to improve throughput. Future standards should be composed of complex organic/inorganic mixtures, similar to what is found in the atmosphere, and perhaps will more accurately account for any aerosol mixture effects on compositional quantification.

  14. Contact efflorescence as a pathway for crystallization of atmospherically relevant particles.

    PubMed

    Davis, Ryan D; Lance, Sara; Gordon, Joshua A; Ushijima, Shuichi B; Tolbert, Margaret A

    2015-12-29

    Inadequate knowledge of the phase state of atmospheric particles represents a source of uncertainty in global climate and air quality models. Hygroscopic aqueous inorganic particles are often assumed to remain liquid throughout their atmospheric lifetime or only (re)crystallize at low relative humidity (RH) due to the kinetic limitations of efflorescence (salt crystal nucleation and growth from an aqueous solution). Here we present experimental observations of a previously unexplored heterogeneous nucleation pathway that we have termed "contact efflorescence," which describes efflorescence initiated by an externally located solid particle coming into contact with the surface of a metastable aqueous microdroplet. This study demonstrates that upon a single collision, contact efflorescence is a pathway for crystallization of atmospherically relevant aqueous particles at high ambient RH (≤80%). Soluble inorganic crystalline particles were used as contact nuclei to induce efflorescence of aqueous ammonium sulfate [(NH4)2SO4], sodium chloride (NaCl), and ammonium nitrate (NH4NO3), with efflorescence being observed in several cases close to their deliquescence RH values (80%, 75%, and 62%, respectively). To our knowledge, these observations represent the highest reported efflorescence RH values for microdroplets of these salts. These results are particularly important for considering the phase state of NH4NO3, where the contact efflorescence RH (∼20-60%) is in stark contrast to the observation that NH4NO3 microdroplets do not homogeneously effloresce, even when exposed to extremely arid conditions (<1% RH). Considering the occurrence of particle collisions in the atmosphere (i.e., coagulation), these observations of contact efflorescence challenge many assumptions made about the phase state of inorganic aerosol. PMID:26668396

  15. The generation of diesel exhaust particle aerosols from a bulk source in an aerodynamic size range similar to atmospheric particles

    PubMed Central

    Cooney, Daniel J; Hickey, Anthony J

    2008-01-01

    The influence of diesel exhaust particles (DEP) on the lungs and heart is currently a topic of great interest in inhalation toxicology. Epidemiological data and animal studies have implicated airborne particulate matter and DEP in increased morbidity and mortality due to a number of cardiopulmonary diseases including asthma, chronic obstructive pulmonary disorder, and lung cancer. The pathogeneses of these diseases are being studied using animal models and cell culture techniques. Real-time exposures to freshly combusted diesel fuel are complex and require significant infrastructure including engine operations, dilution air, and monitoring and control of gases. A method of generating DEP aerosols from a bulk source in an aerodynamic size range similar to atmospheric DEP would be a desirable and useful alternative. Metered dose inhaler technology was adopted to generate aerosols from suspensions of DEP in the propellant hydrofluoroalkane 134a. Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm. Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process. Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene) in the particles resulting from the aerosolization process. PMID:19337412

  16. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    SciTech Connect

    Farquar, G; Leif, R

    2009-07-15

    Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  17. Field and laboratory studies of atmospheric reactive mercury: Gas-particle partitioning and sources

    NASA Astrophysics Data System (ADS)

    Rutter, Andrew Philip

    Certain aspects of atmospheric reactive mercury (RM) source-receptor relationships are not well understood. The objective of this dissertation was to improve the understanding of these relationships in the following areas: (i) gas-particle partitioning, and; (ii) the local impacts of RM source emissions. A novel aerosol reactor was developed to study gas-particle partitioning of RM using synthetic atmospheric aerosol containing picogram concentrations of RM. The RM in the aerosol was collected in an offline mode with filters and sorbent, and analyzed with Thermal Desorption Analysis (TDA). The offline-TDA collection and analysis method was compared with a commercial real time ambient mercury analyzer and two wet analysis methods using ambient measurements. The offline-TDA method performed well in comparison to the established techniques. The dependencies of gas-particle partitioning coefficients upon temperature and particle composition were determined and parameterized from field studies and laboratory experiments. The volatility of RM increased with ambient temperature in urban aerosol and laboratory aerosol of ammonium sulfate and adipic acid. The dependence of RM gas-particle partitioning on particle composition were determined using synthetic atmospheric aerosol generated in the laboratory. RM partitioned predominantly to the particle phase in particles of sodium nitrate, sodium chloride and potassium chloride, but was much more volatile in particles made of ammonium sulfate, levoglucosan and adipic acid. The impacts of RM sources on local receptors were studied in southern Wisconsin and Mexico City. RM measurements were made over a year in Milwaukee, WI (urban) and Devil's Lake State Park, WI (rural). An urban excess of all three mercury species was detected in Milwaukee, WI. The urban excess was attributed to a higher density of mercury emissions in the Milwaukee, WI-Chicago, IL area. The impact of local sources of RM on both sites was found to dominate the atmospheric concentrations. PHg and RGM measurements were made in Mexico City over 2.5 weeks. Diurnal concentration variations with nocturnal maxima pointed to nightly transport of air into the city from the industrial area to the north. RM partitioned predominantly to the particle phase in most of the plumes.

  18. The role of low-volatility organic compounds in initial particle growth in the atmosphere.

    PubMed

    Tröstl, Jasmin; Chuang, Wayne K; Gordon, Hamish; Heinritzi, Martin; Yan, Chao; Molteni, Ugo; Ahlm, Lars; Frege, Carla; Bianchi, Federico; Wagner, Robert; Simon, Mario; Lehtipalo, Katrianne; Williamson, Christina; Craven, Jill S; Duplissy, Jonathan; Adamov, Alexey; Almeida, Joao; Bernhammer, Anne-Kathrin; Breitenlechner, Martin; Brilke, Sophia; Dias, Antònio; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Gysel, Martin; Hansel, Armin; Hoyle, Christopher R; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Krapf, Manuel; Kürten, Andreas; Laaksonen, Ari; Lawler, Michael; Leiminger, Markus; Mathot, Serge; Möhler, Ottmar; Nieminen, Tuomo; Onnela, Antti; Petäjä, Tuukka; Piel, Felix M; Miettinen, Pasi; Rissanen, Matti P; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Sengupta, Kamalika; Sipilä, Mikko; Smith, James N; Steiner, Gerhard; Tomè, Antònio; Virtanen, Annele; Wagner, Andrea C; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Carslaw, Kenneth S; Curtius, Joachim; Dommen, Josef; Kirkby, Jasper; Kulmala, Markku; Riipinen, Ilona; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

    2016-05-26

    About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst of new particles near midday. Atmospheric observations show that the growth rate of new particles often accelerates when the diameter of the particles is between one and ten nanometres. In this critical size range, new particles are most likely to be lost by coagulation with pre-existing particles, thereby failing to form new cloud condensation nuclei that are typically 50 to 100 nanometres across. Sulfuric acid vapour is often involved in nucleation but is too scarce to explain most subsequent growth, leaving organic vapours as the most plausible alternative, at least in the planetary boundary layer. Although recent studies predict that low-volatility organic vapours contribute during initial growth, direct evidence has been lacking. The accelerating growth may result from increased photolytic production of condensable organic species in the afternoon, and the presence of a possible Kelvin (curvature) effect, which inhibits organic vapour condensation on the smallest particles (the nano-Köhler theory), has so far remained ambiguous. Here we present experiments performed in a large chamber under atmospheric conditions that investigate the role of organic vapours in the initial growth of nucleated organic particles in the absence of inorganic acids and bases such as sulfuric acid or ammonia and amines, respectively. Using data from the same set of experiments, it has been shown that organic vapours alone can drive nucleation. We focus on the growth of nucleated particles and find that the organic vapours that drive initial growth have extremely low volatilities (saturation concentration less than 10(-4.5) micrograms per cubic metre). As the particles increase in size and the Kelvin barrier falls, subsequent growth is primarily due to more abundant organic vapours of slightly higher volatility (saturation concentrations of 10(-4.5) to 10(-0.5) micrograms per cubic metre). We present a particle growth model that quantitatively reproduces our measurements. Furthermore, we implement a parameterization of the first steps of growth in a global aerosol model and find that concentrations of atmospheric cloud concentration nuclei can change substantially in response, that is, by up to 50 per cent in comparison with previously assumed growth rate parameterizations. PMID:27225126

  19. Supersonic Particle Impacts: Cold Spray Deposition of Polymeric Material

    NASA Astrophysics Data System (ADS)

    Bush, Trenton; Schmidt, David; Rothstein, Jonathan P.

    2015-11-01

    When a solid, ductile particle impacts a substrate at sufficient velocity, the resulting heat, pressure, and plastic deformation at the interface can produce bonding. The use of a supersonic gas flow to accelerate such particles is known as Cold Spray deposition. The Cold Spray process has been commercialized for some metallic materials, but further research is required to unlock the exciting material properties possible with polymeric compounds. In this work, we present a combined computational and experimental study whose aim is to define the necessary flow conditions for a convergent-divergent de Laval nozzle to produce successful bonding in a range of polymers. From our initial exploration of temperature-pressure space, we will reveal a material dependent `window of deposition' where successful deposition is possible. Furthermore, we will present our computational work on the development of an optimized nozzle profile that maximizes particle total energy (kinetic plus thermal) upon impact and thus maximizes the likelihood of successful deposition. These predictions will be confirmed by the experimental results presented.

  20. Pollution of Stellar Atmospheres by Interstellar Dust Material: A Possible Solution to the G Dwarf Problem

    NASA Astrophysics Data System (ADS)

    Ragot, B. R.

    2001-09-01

    Accretion of interstellar dust material onto stellar atmospheres could be responsible for the lack of low-metallicity G dwarfs observed in the disk of our Galaxy, known as the G dwarf problem. This interpretation of the G dwarf problem would be consistent with a peaked distribution of G dwarf metallicities and reconcile the observations of both a well-mixed interstellar gas and a large scatter in the age-metallicity relation. The absence of G dwarf problem in the Galactic halo could also be easily explained by the lower density of dust grains and the higher velocity of the stars in the halo. In order to test this idea of atmospheric pollution by interstellar dust material, the Sun accretion rate of interstellar dust (ISD) iron is estimated, making use of in situ measurements at AU distances from the Sun and taking into account the solar gravitational and radiation pressure forces to describe the grains dynamics closer to the Sun. The dust grains do not actually reach the Sun surface, but their iron content does after their sublimation at a few solar radii. The flux of ISD measured by Ulysses and Galileo results in an iron accretion rate of the order of 10-20 Msolar yr-1 the flux of very large ISD recently measured with AMOR gives an accretion rate several orders of magnitude higher, 10-17 Msolar yr-1 being a probable value. For a G dwarf of real metallicity [Fe/H]r, the metallicity of the stellar atmosphere (the observed one) will therefore differ from the metallicity [Fe/H]r of the stellar interior if the dilution of the accreted iron into the interior of the star happens on a timescale longer than 1-100×10[Fe/H]r+3 yr. Further studies of the particle transport between the atmosphere and convection zone will be needed to conclude about the plausibility of these values.

  1. Hydrostatic Simulation of Earth's Atmospheric Gas Using Multi-particle Collision Dynamics

    NASA Astrophysics Data System (ADS)

    Pattisahusiwa, Asis; Purqon, Acep; Viridi, Sparisoma

    2016-01-01

    Multi-particle collision dynamics (MPCD) is a mesoscopic simulation method to simulate fluid particle-like flows. MPCD has been widely used to simulate various problems in condensed matter. In this study, hydrostatic behavior of gas in the Earth's atmospheric layer is simulated by using MPCD method. The simulation is carried out by assuming the system under ideal state and is affected only by gravitational force. Gas particles are homogeneous and placed in 2D box. Interaction of the particles with the box is applied through implementation of boundary conditions (BC). Periodic BC is applied on the left and the right side, specular reflection on the top side, while bounce-back on the bottom side. Simulation program is executed in Arch Linux and running in notebook with processor Intel i5 @2700 MHz with 10 GB DDR3 RAM. The results show behaviors of the particles obey kinetic theory for ideal gas when gravitational acceleration value is proportional to the particle mass. Density distribution as a function of altitude also meets atmosphere's hydrostatic theory.

  2. Improved characterization of gas-particle partitioning for per- and polyfluoroalkyl substances in the atmosphere using annular diffusion denuder samplers.

    PubMed

    Ahrens, Lutz; Harner, Tom; Shoeib, Mahiba; Lane, Douglas A; Murphy, Jennifer G

    2012-07-01

    Gas-phase perfluoroalkyl carboxylic acids (PFCAs) sorb strongly on filter material (i.e., GFF, QFF) used in conventional high volume air samplers, which results in an overestimation of the particle-phase concentration. In this study, we investigated an improved technique for measuring the gas-particle partitioning of per- and polyfluoroalkyl substances (PFASs) using an annular diffusion denuder sampler. Samples were analyzed for 7 PFAS classes [i.e., PFCAs, perfluoroalkane sulfonic acids (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer methacrylates (FTMACs), fluorotelomer acrylates (FTACs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamidoethanols (FOSEs)]. The measured particulate associated fraction (Φ') using the diffusion denuder sampler generally followed the trend FTACs (0%) < FTOHs (~8%) < FOSAs (~21%) < PFSAs (~29%) < FOSEs (~66%), whereas the Φ' of the C(8)-C(18) PFCAs increased with carbon chain length, and ranged from 6% to 100%. The ionizability of some PFASs, when associated with particles, is an important consideration when calculating the gas-particle partitioning coefficient as both ionic and neutral forms can be present in the particles. Here we differentiate between a gas-particle partitioning coefficient for neutral species, K(p), and one that accounts for both ionic and neutral species of a compound, K(p)'. The measured K(p)' for PFSAs and PFCAs was 4-5 log units higher compared to the interpolated K(p) for the neutral form only. The measured K(p)' can be corrected (to apply to the neutral form only) with knowledge of the pK(a) of the chemical and the pH of the condensed medium ("wet" particle or aqueous aerosol). The denuder-based sampling of PFASs has yielded a robust data set that demonstrates the importance of atmospheric pH and chemical pK(a) values in determining gas-particle partitioning of PFASs. PMID:22606993

  3. Assembling and properties of the polymer-particle nanostructured materials

    NASA Astrophysics Data System (ADS)

    Sheparovych, Roman

    Complementary properties of the soft and hard matter explain its common encounter in many natural and manmade applications. A combination of flexible organic macromolecules and hard mineral clusters results in new materials far advantageous than its constituents alone. In this work we study assembling of colloidal nanocrystals and polymers into complex nanostructures. Magnetism, surface wettability and adhesion comprise properties of interest for the obtained nanocomposites. Applying a magnetic field induces a reversible 1D ordering of the magnetically susceptible particles. This property was employed in the fabrication of the permanent chains of magnetite nanocrystals (d=15nm). In the assembling process the aligned particles were bound together using polyelectrolyte macromolecules. The basics of the binding process involved an electrostatic interaction between the positively charged polyelectrolyte and the negative surface of the particles (aqueous environment). Adsorption of the polymer molecules onto several adjacent particles in the aligned 1D aggregate results in the formation of the permanent particulate chains. Positive charges of the adsorbed polyelectrolyte molecules stabilize the dispersion of the obtained nanostructures in water. Magnetization measurements revealed that superparamagnetic nanoparticles, being assembled into 1D ordered structures, attain magnetic coercivity. This effect originates from the magnetostatic interaction between the neighboring magnetite nanocrystals. The preferable dipole alignment of the assembled nanoparticles is directed along the chain axis. Another system studied in this project includes polymer-particle responsive surface coatings. Tethered polymer chains and particles bearing different functionalities change surface properties upon restructuring of the composite layer. When the environment favors polymer swelling (good solvent), the polymer chains segregate to the surface and cover the particles. In the opposite case, when polymer is in a dry state or in poor solvent its chains collapse and expose the particulate layer. The goal was to design responsive surface system possessing low adhesiveness in air and in aqueous environments. Two factors provide low adhesion: surface roughness induced by the particles monolayer and fast adapting of low surface/interfacial energy upon changing environmental properties. Surface roughness reduces the total area of the contacting asperities, while selective switching of the surface composition provides a low interfacial energy. In air the hydrophilic polymer chains collapse and uncover hydrophobic particles, while in water the polymer segregates on top of the particles thus lowering surface water interfacial energy. Silica particles coated with mixed polymer brushes have been used for modification of surface wettability. In particular, aqueous dispersions of the modified silica produced superhydrophobic surface coatings. Hydrophobicity of the casted layers was achieved by modification of the particle surface with either polystyrene (PS) or polydimethylsiloxane (PDMS). Stable aqueous dispersions of these particles were obtained by co-grafting of the hydrophilic polymers. Selective segregation of the polymer chains upon changing environment from water to air rendered desired surface properties of colloids in dispersion and in dry state. To achieve superhydrophobic effect, roughness of the casted layers was increased by controlled aggregation of the original nano-sized particles. By depositing their flocks onto substrate surface we created uniformly distributed micro-sized asperities. Being composed of the nanosized particles, large asperities created multiscale surface roughness with a structure similar to the surface of lotus leaves.

  4. Processing of atmospheric particles caught in the act via STXM/NEXAFS

    NASA Astrophysics Data System (ADS)

    Steimer, S.; Lampimäki, M.; Grzinic, G.; Coz, E.; Watts, B.; Raabe, J.; Ammann, M.

    2012-12-01

    Atmospheric aerosols are an important focus of environmental research due to their effect on climate and human health. Among their main constituents are mineral dust and organic particles. Both types of particles directly and indirectly affect our climate through scattering and absorption of radiation and through acting as cloud condensation nuclei respectively. Organic particles are also of significant concern with respect to their health effects. Mineral dust particles in addition serve as a primary external iron source to the open ocean and the bioavailability of iron from these particles is highly dependent on the oxidation state of the metal. The environmental impact of atmospheric particles depends on their physical and chemical properties, which might change upon chemical ageing. In this study we therefore investigated the changes in chemical composition and morphology of mineral dust and organic particle proxies (Arizona test dust and shikimic acid, respectively) upon in situ exposure to ozone or nitrogen oxides in presence of humidity. This was achieved by monitoring changes at the C and O K-edges as well as the metal L-edges via scanning transmission X-ray microscopy (STXM) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Measurements were conducted at the PolLux beamline at Swiss Light Source. All experiments were conducted in an environmental micro reactor, designed specifically for the end station, to enable the investigation in situ. We observed oxidation of shikimic acid particles in situ during exposure to ozone at different humidities, whereby humidity was found to be a critical factor controlling the rate of the reaction. We also obtained well resolved iron distribution maps from the individual submicrometer size mineral dust particles before and after exposure to nitrogen oxides.

  5. Generation of volatile organic compounds by alpha particle degradation of WIPP plastic and rubber material

    SciTech Connect

    Reed, D.T.; Molecke, M.A.

    1993-12-31

    The generation of volatile organic compounds (VOCs), hydrogen, and carbon oxides due to alpha particle irradiation of polyethylene, polyvinylchloride, hypalon, and neoprene, is being investigated. A wide diversity of VOCs was found including alkenes, alkanes, alcohols, ketones, benzene derivatives, and nitro compounds. Their yields however, were quite low. The relative amounts of these compounds depended on the material, atmosphere present, and the absorbed dose. This investigation will help evaluate the effect of ionizing radiation on the long-term performance assessment and regulatory compliance issues related to the Waste Isolation Pilot Plant (WIPP).

  6. Reactive Atmospheric Plasma Spraying of AlN Coatings: Influence of Aluminum Feedstock Particle Size

    NASA Astrophysics Data System (ADS)

    Shahien, Mohammed; Yamada, Motohiro; Yasui, Toshiaki; Fukumoto, Masahiro

    2011-03-01

    Feedstock powder characteristics (size distribution, morphology, shape, specific mass, and injection rate) are considered to be one of the key factors in controlling plasma-sprayed coatings microstructure and properties. The influence of feedstock powder characteristics to control the reaction and coatings microstructure in reactive plasma spraying process (RPS) is still unclear. This study, investigated the influence of feedstock particle size in RPS of aluminum nitride (AlN) coatings, through plasma nitriding of aluminum (Al) feedstock powders. It was possible to fabricate AlN-based coatings through plasma nitriding of all kinds of Al powders in atmospheric plasma spray (APS) process. The nitriding ratio was improved with decreasing the particle size of feedstock powder, due to improving the nitriding reaction during flight. However, decreasing the particle size of feedstock powder suppressed the coatings thickness. Due to the loss of the powder during the injection, the excessive vaporization of fine Al particles and the completing nitriding reaction of some fine Al particles during flight. The feedstock particle size directly affects on the nitriding, melting, flowability, and the vaporization behaviors of Al powders during spraying. It concluded that using smaller particle size powders is useful for improving the nitriding ratio and not suitable for fabrication thick AlN coatings in reactive plasma spray process. To fabricate thick AlN coatings through RPS, enhancing the nitriding reaction of Al powders with large particle size during spraying is required.

  7. Gas and particle size distributions of polychlorinated naphthalenes in the atmosphere of Beijing, China.

    PubMed

    Zhu, Qingqing; Zhang, Xian; Dong, Shujun; Gao, Lirong; Liu, Guorui; Zheng, Minghui

    2016-05-01

    Polychlorinated naphthalenes (PCNs) were listed as persistent organic pollutants in the Stockholm Convention in 2015. Despite numerous studies on PCNs, little is known about their occurrence in atmospheric particulate matter of different sizes. In this study, 49 PCN congeners were investigated for their concentrations and size-specific distributions in an urban atmosphere, and preliminary exposure assessments were conducted. Ambient air samples were collected using a high-volume cascade impactor for division into a gas fraction and four particle size fractions. Samples were collected from October 2013 to June 2014 at an urban site in Beijing, China. The concentration range for PCNs in the atmosphere (gas + particle fractions) was 6.77-25.90 pg/m(3) (average 16.28 pg/m(3)). The particle-bound concentration range was 0.17-2.78 pg/m(3) (average 1.73 pg/m(3)). Therefore, PCNs were mainly found in the gas phase. The concentrations of PCNs in a fraction increased as the particle size decreased (dae > 10 μm, 10 μm ≥ dae > 2.5 μm, 2.5 μm ≥ dae > 1.0 μm and dae ≤ 1.0 μm). Consequently, PCNs were ubiquitous in inhalable fine particles, and the ΣPCNs associated with PM1.0 and PM2.5 reached 68.4% and 84.3%, respectively. Tetra-CNs and penta-CNs (the lower chlorinated homologues) predominated in the atmosphere. The homologue profiles in different size particles were almost similar, but the particulate profiles were different from those in the gas phase. Among the individual PCNs identified, CN38/40, CN52/60 and CN75 were the dominant compounds in the atmosphere. CN66/67 and CN73 collectively accounted for most of the total dioxin-like TEQ concentrations of the PCNs. Exposure to toxic compounds, such as PCNs present in PM1.0 or PM2.5, may affect human health. This work presents the first data on size-specific distributions of PCNs in the atmosphere. PMID:26840526

  8. Characterization of Organic Coatings on Hygroscopic Salt Particles and their Atmospheric Impacts

    SciTech Connect

    Zelenyuk, Alla; Ezell, Michael J.; Perraud, Veronique; Johnson, Stanley N.; Bruns, Emily; Yu, Yong; Imre, D.; Alexander, M. L.; Finlayson-Pitts, Barbara J.

    2010-03-30

    The photooxidation of α-pinene in the presence of NO2, with and without added NaNO3 seed particles, has been studied in a large diameter flow tube. Particles formed by homogeneous nucleation and by condensation on the pre-existing seeds were sampled at various stages of the reaction, dried using four diffusion dryers, size selected at different mobility diameters (dm) using a differential mobility analyzer (DMA), and characterized with a single particle mass spectrometer (SPLAT II). It was found that homogeneously nucleated particles are spherical, have a density (ρ) of 1.25 ± 0.02 g cm-3 (± 2 σ) and contain a significant amount of organic nitrates. The mass spectra of the low volatility products condensed on the NaNO3 seed particles were found to be virtually the same as in the case of homogeneous nucleation. The data show that the presence of even a submonolayer of organics on the NaNO3 particles causes water retention that leads to a decrease in particle density and that the amount of water retained increases with organic coating thickness. Thicker coatings appear to inhibit water evaporation from the particle seeds altogether. This suggests that in the atmosphere, where low volatility organics are plentiful, some hygroscopic salts will retain water and have different densities and refractive indices than expected in the absence of the organic coating. This water retention combined with the organic shell on the particles can potentially impact light scattering by these particles and activity as cloud condensation nuclei (CCN), as well as heterogeneous chemistry and photochemistry on the particles.

  9. Mass-particle size distributions of atmospheric dust and the dry deposition of dust to the remote ocean

    NASA Astrophysics Data System (ADS)

    Arimoto, R.; Ray, B. J.; Lewis, N. F.; Tomza, U.; Duce, R. A.

    1997-07-01

    Size-separated mineral aerosol samples were collected and analyzed to investigate the relationships between the mass-particle size distributions (MSDs) of dust particles and the dust loadings in the atmosphere. The data also were used to assess the changes in the MSDs of dust in relation to transport processes and especially the associated effects on dry deposition. Atmospheric dust concentrations, as indicated by aluminum or scandium, in samples collected from three sites in the remote North Atlantic were higher than those in samples collected during a cruise in the North Pacific on board the R/V Moana Wave. However, the mass median diameters (MMDs) for the North Pacific samples were both larger on average (˜3 μm versus ˜2 μm aerodynamic equivalent diameter) and more variable than those from the North Atlantic; this difference was attributed to wet conditions and particle aggregation over the North Pacific. In addition, for the ensemble of all samples the geometric standard deviations of the mass-particle size distributions, which are analogous to the sorting values used to characterize sedimentary materials, tended to vary inversely and nonlinearly with the mass median diameters. Model-derived dry deposition velocities for the samples were at most weakly related to either the dust concentrations or the MMDs. However, the dry deposition velocities for two subsets of samples were correlated with the geometric standard deviations of the distributions; this is further evidence that the mass flux of dust via dry deposition can be controlled by a relatively small fraction of aerodynamically large particles.

  10. Assessment of atmospheric ultrafine carbon particle-induced human health risk based on surface area dosimetry

    NASA Astrophysics Data System (ADS)

    Chio, Chia-Pin; Liao, Chung-Min

    Evidence shows a strong correlation between human mortality/morbidity and atmospheric ultrafine carbon particle (UFCP with aerodynamic diameter <18 nm). Theoretical and experimental studies have attempted to use mass concentration/dose as exposure dosimetry to construct the dose-response relationships. Yet little attention has been given to the problem of using surface area dosimetry in UFCP-related risk assessment. We introduced an integrated risk assessment framework based on surface area dosimetry to estimate the adverse health potential risk exposed to atmospheric UFCP. We used the neutrophil cells elevation effect as adverse health effect endpoint. We reanalyzed the published data of UFCP particle diameter ( dp) and associated specific surface area (SSA) to reconstruct their relationship through log-linear regression method. Our results show that smaller particle size ( dp < 51 nm) demonstrated steep slope (ln SSA = 11.0-2.03 ln dp), whereas larger particle size ( dp > 51 nm) was found close to the theoretical relationship (ln SSA = 8.65-1.20 ln dp). We applied the modeled relationships to estimate the surface area doses of human inhaled particles in specific scenarios or subgroups. Our findings show that Adult and Youth subgroups in northern Taiwan region posed the highest potential risk, indicating that the median 10% exceedance risks are 39.6 (95%CI: 36.4-42.9) fold compared to control based on neutrophil cells elevation effect. The result provides a preliminary aspect for discussing the human health adverse effect exposed to atmospheric UFCP for specific groups based on particle surface area dosimetry.

  11. Nano- and Microscale Particles in Vortex Motions in Earth's Atmosphere and Ionosphere

    SciTech Connect

    Popel, S. I.; Izvekova, Yu. N.; Shukla, P. K.

    2010-12-14

    Vortex motions in the atmosphere are shown to be closely connected with dynamics of the dust nano- and microscale particles. The mechanism by which nano- and microscale particles are transported from the troposphere into the lower stratosphere by synoptic-scale vortices, simulated by the soliton solutions to the Charney-Obukhov equations (Rossby vortices), is described. Redistribution of dust particles in the ionosphere as a result of vortical motions is discussed. It is shown that excitation of acoustic-gravitational vortices at altitudes of 110-130 km as a result of development of acoustic-gravitational wave instability, associated with nonzero balance of heat fluxes, owing to solar radiation, water vapors condensation, infrared emission of the atmosphere, and thermal conductivity, leads to a substantial transportation of dust particles and their mixing at altitudes of 110-120 km. One of the ways of transportation of dust particles in the ionosphere is shown to be vertical flows (streamers), which are generated by dust vortices as a result of development of parametric instability.

  12. Angular Distribution of Charged Particles in the Atmosphere- Results of the ADAM Experiment on BEXUS 19

    NASA Astrophysics Data System (ADS)

    Martensen, S.; Brudern, M.; Christiansen, F.; Koberle, M.; Trautwein, D.; Wraase, S.; Bottcher, S.; Burmeister, S.; Heber, B.; Wimmer-Schweingruber, R.

    2015-09-01

    Particle showers, which produce a large number of secondary particles, are generated by the interaction of high-energy cosmic ray particles with the Earth's atmosphere. The Team ADAM (Angular Distribution of charged partides - Atmosphere Measurement) has flown an experiment to measure the altitude- dependent angular distribution of secondary charged particles on a stratospheric balloon within the REXUS/BEXUS programme in October 2014. We designed a sensor head consisting of 16 planar silicon semi-conductor detectors (SSDs), which allowed us to determine the zenith-angle of individual particles by coincidence measurements. After a year of development and testing, on October 9th the instrument performed measurements for 4 hours in an altitude of 27 km in northern Sweden. In this contribution measurements performed during the flight in comparison to ones obtained on ground will be presented. On the one hand we focus on the count and dose rate profiles as functions of residual pressure, on the other hand we discuss the angular distribution below and above the PFOTZERMaximum.

  13. Dynamics of Space Particles and Spacecrafts Passing by the Atmosphere of the Earth

    PubMed Central

    Prado, Antonio Fernando Bertachini de Almeida; Golebiewska, Justyna

    2013-01-01

    The present research studies the motion of a particle or a spacecraft that comes from an orbit around the Sun, which can be elliptic or hyperbolic, and that makes a passage close enough to the Earth such that it crosses its atmosphere. The idea is to measure the Sun-particle two-body energy before and after this passage in order to verify its variation as a function of the periapsis distance, angle of approach, and velocity at the periapsis of the particle. The full system is formed by the Sun, the Earth, and the particle or the spacecraft. The Sun and the Earth are in circular orbits around their center of mass and the motion is planar for all the bodies involved. The equations of motion consider the restricted circular planar three-body problem with the addition of the atmospheric drag. The initial conditions of the particle or spacecraft (position and velocity) are given at the periapsis of its trajectory around the Earth. PMID:24396298

  14. Escape probability of Martian atmospheric particles: controlling effects of the electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Fang, X.; Liemohn, M. W.; Nagy, A. F.; Luhmann, J. G.; Ma, Y.

    2009-12-01

    This study quantifies several factors controlling the probability of a pickup oxygen ion to escape from the Mars upper atmosphere. Our Monte Carlo model releases billions of test particles through the electromagnetic fields of a magnetohydrodynamic model solution, monitoring their motion due to gravity and the Lorentz force throughout the simulation domain, which extends from the 200 km exobase altitude to 5 Martian radii from the center. We focus on the escape chances of the ions created at low altitudes on the dayside, where most ion production is located. The simulation results show that the electromagnetic fields are the dominant factor, surpassing the deceleration of gravity, in controlling ion transport and thus determine whether particles ultimately escape Mars or return to the planet. In a simulation case in which the strongest crustal fields face the Sun at nominal solar minimum conditions, on average only 45% of isotropically distributed new-born particles at ~400 km altitude are able to escape, even with a relatively high initial energy of ~10 eV. The percentage value slightly increases to 47%, if the velocity distribution is assumed to be half-isotropic without downward moving particles. The particle kinetic energy and the local time of the crustal fields are also important factors greatly influencing the escape probability. Furthermore, there is a distinct hemispheric asymmetry in the escape probability distribution, as defined by the upstream convection electric field direction. These findings imply that electromagnetic field effects are crucial in estimating Martian atmospheric loss for comparison with photochemical escape rates

  15. Flux induced growth of atmospheric nano-particles by organic vapors

    NASA Astrophysics Data System (ADS)

    Wang, J.; McGraw, R. L.; Kuang, C.

    2012-09-01

    Atmospheric aerosols play critical roles in air quality, public health, and visibility. In addition, they strongly influence climate by scattering solar radiation and by changing the reflectivity and lifetime of clouds. One major but still poorly understood source of atmospheric aerosol is new particle formation, which consists of the formation of thermodynamically stable clusters from trace gas molecules (homogeneous nucleation) followed by growth of these clusters to a detectable size (~3 nm). Because freshly nucleated clusters are most susceptible to loss due to high rate of coagulation with pre-existing aerosol population, the initial growth rate strongly influences the rate of new particle formation and ambient aerosol population. Whereas many field observations and modeling studies indicate that organics enhance the initial growth of the clusters and therefore new particle formation, thermodynamic considerations would suggest that the strong increase of equilibrium vapor concentration due to cluster surface curvature (Kelvin effect) may prevent ambient organics from condensing on these small clusters. Here the initial condensational growth of freshly nucleated clusters is described as heterogeneous nucleation of organic molecules onto these clusters. We find that the strong gradient in cluster population with respect to its size lead to positive cluster number flux, and therefore driving the growth of clusters substantially smaller than the Kelvin diameter, conventionally considered as the minimum particle size that can be grown through condensation. The conventional approach neglects this contribution from the cluster concentration gradient, and underestimates the rate of new particle formation by a factor of up to 60.

  16. Vertical concentration profiles of dust particles in the atmospheric surface layer

    NASA Astrophysics Data System (ADS)

    Souza Freire Grion, Livia; Chamecki, Marcelo

    2013-11-01

    The study of the emission of dust particles from soil surfaces into the atmospheric boundary layer (ABL) has important applications to different environmental problems, from local air quality to large-scale aerosol transport and its interaction with climate. Due to the difficulty of measuring surface dust flux, a model relating it to the vertical profile of mean concentration is needed. In this study, we use Large-Eddy Simulation of the ABL to evaluate the effects of particle size and turbulence on the relationship between dust flux and concentration profiles. Results show that for very small particles (less than 5 micrometers) the settling velocity is usually negligible and the mean concentration displays a logarithmic profile. For large particles (more than 30 micrometers), there is an approximate balance between vertical turbulent diffusion and gravitational settling, so that Prandtl's power-law solution holds. However, a more general solution including non-zero net fluxes and gravitational settling exists, and it is in agreement with LES results for all particle sizes. Effects of atmospheric stability are also investigated. Funding from the Science Without Borders program (CNPq, Brazil) is gratefully acknowledged.

  17. Dynamics of space particles and spacecrafts passing by the atmosphere of the Earth.

    PubMed

    Gomes, Vivian Martins; Prado, Antonio Fernando Bertachini de Almeida; Golebiewska, Justyna

    2013-01-01

    The present research studies the motion of a particle or a spacecraft that comes from an orbit around the Sun, which can be elliptic or hyperbolic, and that makes a passage close enough to the Earth such that it crosses its atmosphere. The idea is to measure the Sun-particle two-body energy before and after this passage in order to verify its variation as a function of the periapsis distance, angle of approach, and velocity at the periapsis of the particle. The full system is formed by the Sun, the Earth, and the particle or the spacecraft. The Sun and the Earth are in circular orbits around their center of mass and the motion is planar for all the bodies involved. The equations of motion consider the restricted circular planar three-body problem with the addition of the atmospheric drag. The initial conditions of the particle or spacecraft (position and velocity) are given at the periapsis of its trajectory around the Earth. PMID:24396298

  18. Propagation in atmosphere of ablated material from femtosecond laser machining of fused silica

    NASA Astrophysics Data System (ADS)

    Bowman, Trevor; Canfield, Brian; Davis, Lloyd

    2014-03-01

    Femtosecond laser pulses provide a means to machine structures with small heat-affected areas through highly non-linear mechanisms that enable direct writing of nanoscale features, which can be applied for fabricating a range of devices, including micro-optics and micro-fluidics. A single, tightly focused ultrashort pulse induces extreme conditions on sub-picosecond time-scales and forms a region of expanding plasma beyond the focal region. This plasma, which typically limits the depth of the nanoscale features to create shallow craters, results in the ejection of micro/nano-particles. The generation and use of these particles have a large range of applications in nanotechnology. We have studied the propagation, in atmosphere, of micro/nano particles ejected using single pulses from a 100 fs, 800 nm laser tightly focused with either a line or spot profile near the back surface of a fused silica substrate. The substrate was translated such that a fresh portion was ablated with each pulse. Time-gated images of the ejected material were taken using an intensified charged coupled device camera with additional illumination along the axial direction. Physical mechanisms and experimental results to date will be discussed.

  19. The importance of energetic particle precipitation on the chemical composition of the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Thorne, R. M.

    1980-01-01

    The present review deals with the importance of three distinct classes of precipitation which directly deposit energy into the middle atmosphere, viz. galactic cosmic radiation, energetic solar protons and relativistic electron precipitation from the earth's radiation belts. Chemical considerations during particle precipitation are discussed, with special emphasis on the relative production rate of odd nitrogen and odd hydrogen species during ionizing particle precipitation. The long residence time of NO in the upper stratosphere, where catalytic interaction with O3 is most effective, requires that this mechanism be included in future modeling of global distribution of O3. Other situations causing O3 depletion are also identified.

  20. Models for close-in atmospheric dispersion, explosive releases, and particle deposition

    SciTech Connect

    Bloom, S.G.

    1993-10-06

    Relatively simple models are presented to simulate close-in atmospheric dispersion, explosive releases, and particle deposition. Close-in generally refers to distances less than 50 m downwind from the source. These models assume simple gas dispersion (no chemical reactions, neutral buoyancy) and that particles behave as a gas expect they can be removed from the plume by a simple, deposition-velocity mechanism. These models have been combined into a QuickBASIC program (INEXPLC.BAS) and its PC executable form (INEXPLC.EXE). These programs, along with sample input and output files, are available from the author.

  1. Brighter material on Deimos - A particle size effect in a carbonaceous material?

    NASA Technical Reports Server (NTRS)

    French, L. M.; Veverka, J.; Thomas, P.

    1988-01-01

    The values obtained for brightness ratios between contiguous bright and dark areas on Deimos from Viking Orbiter images, together with the lack of a significant wavelength dependence of these ratios in the 0.4-0.6-micron range, are presently noted to be consistent with particle size fraction measurements of the Murchison CM meteorite. These data, and a near-coincidence of Deimos absolute reflectances with those of laboratory samples, render the present data consistent with both brighter and darker materials on Deimos being akin to carbonaceous chondrites; the material with smaller average particle size is associated with the brighter patches.

  2. Novel applications of atmospheric pressure plasma on textile materials

    NASA Astrophysics Data System (ADS)

    Cornelius, Carrie Elizabeth

    Various applications of atmospheric pressure plasma are investigated in conjunction with polymeric materials including paper, polypropylene non-woven fabric, and cotton. The effect of plasma on bulk and surface properties is examined by treating both cellulosic pulp and prefabricated paper with various plasma-gas compositions. After treatment, pulp is processed into paper and the properties are compared. The method of pulp preparation is found to be more significant than the plasma, but differences in density, strength, and surface roughness are apparent for the pulp vs. paper plasma treatments. The plasma is also used to remove sizes of PVA and starch from poly/cotton and cotton fabric respectively. In both cases plasma successfully removes a significant amount of size, but complete size removal is not achieved. Subsequent washes (PVA) or scouring (cotton) to remove the size are less successful than a control, suggesting the plasma is crosslinking the size that is not etched away. However, at short durations in cold water using an oxygen plasma, slightly more PVA is removed than with a control. For the starch sized samples, plasma and scouring are never as successful at removing starch as a conventional enzyme, but plasma improves dyeability without need for scouring. Plasma is also used to graft chemicals to the surface of polypropylene and cotton fabric. HTCC, an antimicrobial is grafted to polypropylene with successful grafting indicated by x-ray photoemission spectroscopy (XPS), dye tests, and Fourier transform infrared spectroscopy (FTIR). Antimicrobial activity of the grafted samples is also characterized. 3ATAC, a vinyl monomer is also grafted to polypropylene and to cotton. Additives including Mohr's salt, potassium persulfate, and diacrylate are assessed to increase yield. Successful grafting of 3ATAC is confirmed by XPS and dye testing. A combination of all three additives is identified as optimum for maximizing graft yield.

  3. Solar wind and high energy particle effects in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Lastovicka, Jan

    1989-01-01

    The solar wind variability and high energy particle effects in the neutral middle atmosphere are not much known. These factors are important in the high latitude upper mesosphere, lower thermosphere energy budget. They influence temperature, composition (minor constituents of nitric oxide, ozone), circulation (wind system) and airflow. The vertical and latitudinal structures of such effects, mechanisms of downward penetration of energy and questions of energy abundance are largely to be solved. The most important recent finding seems to be the discovery of the role of highly relativistic electrons in the middle atmosphere at L = 3 - 8 (Baker et al., 1987). The solar wind and high energy particle flux variability appear to form a part of the chain of possible Sun-weather (climate) relationships. The importance of such studies in the nineties is emphasized by their role in big international programs STEP and IGBP - Global Change.

  4. Estimating Bacteria Emissions from Inversion of Atmospheric Transport: Sensitivity to Modelled Particle Characteristics

    SciTech Connect

    Burrows, Susannah M.; Rayner, Perter; Butler, T.; Lawrence, M.

    2013-06-04

    Model-simulated transport of atmospheric trace components can be combined with observed concentrations to obtain estimates of ground-based sources using various inversion techniques. These approaches have been applied in the past primarily to obtain source estimates for long-lived trace gases such as CO2. We consider the application of similar techniques to source estimation for atmospheric aerosols, by using as a case study the estimation of bacteria emissions from different ecosystem regions in the global atmospheric chemistry and climate model ECHAM5/MESSy-Atmospheric Chemistry (EMAC). Simulated particle concentrations in the tropopause region and at high latitudes, as well as transport of particles to tundra and land ice regions are shown to be highly sensitive to scavenging in mixed-phase clouds, which is poorly characterized in most global climate models. This may be a critical uncertainty in correctly simulating the transport of aerosol particles to the Arctic. Source estimation via Monte Carlo Markov Chain is applied to a suite of sensitivity simulations and the global mean emissions are estimated. We present an analysis of the partitioning of uncertainties in the global mean emissions that are attributable to particle size, CCN activity, the ice nucleation scavenging ratios for mixed-phase and cold clouds, and measurement error. Uncertainty due to CCN activity or to a 1 um error in particle size is typically between 10% and 40% of the uncertainty due to data uncertainty, as measured by the 5%-ile to 95%-ile range of the Monte Carlo ensemble. Uncertainty attributable to the ice nucleation scavenging ratio in mized-phase clouds is as high as 10% to 20% of the data uncertainty. Taken together, the four model 20 parameters examined contribute about half as much to the uncertainty in the estimated emissions as do the measurements. This was a surprisingly large contribution from model uncertainty in light of the substantial data uncertainty, which ranges from 81% to 870% for each of ten ecosystems for this case study. The effects of these and other model parameters in contributing to the uncertainties in the transport of atmospheric aerosol particles should be treated explicitly and systematically in both forward and inverse modelling studies.

  5. COMPASS - COMparative Particle formation in the Atmosphere using Simulation chamber Study techniques

    NASA Astrophysics Data System (ADS)

    Bonn, B.; Sun, S.; Haunold, W.; Sitals, R.; van Beesel, E.; dos Santos, L.; Nillius, B.; Jacobi, S.

    2013-06-01

    The anthropogenic influence on climate and environment has increased strongly since industrialization about 150 yr ago. The consequences for the atmosphere became more and more apparent and nowadays affect our life quality on Earth progressively. Because of that it is very important to understand the atmospheric processes, on which these effects are based on, in detail. In this study we report the set-up of a novel twin chamber technique that uses the comparative method and establishes an appropriate connection of atmospheric and laboratory methods to broaden the tools for investigations. It is designed to study the impact of certain parameters and gases on ambient processes such as particle formation online and can be applied in a large variety of conditions. The characterisation of both chambers proved that both chambers operate identically with a residence time (xT (COMPASS 1) = 26.5 ± 0.3 min and xT (COMPASS 2) = 26.6 ± 0.4 min) at a typical flow rate of 15 L min-1 and a deposition rate (1.6 ± 0.8) × 10-5 s-1. Comparison measurement showed no significant differences. Therefore operation under atmospheric conditions is trustworthy. To indicate the applicability and the benefit of the system a set of experiments was conducted at different conditions, i.e. urban and remote, enhancing ozone and terpenes as well as reducing sunlight. In the ozone enhanced ambient particle number and volume increased substantially at urban and remote conditions in a different strength. Solar radiation displayed a clear positive effect on particle number as well as terpene addition did at remote conditions. Therefore the system is a useful tool to investigate local precursors, the details of ambient particle formation at surface locations as well as future feedback processes.

  6. Condensation-nuclei (Aitken Particle) measurement system used in NASA global atmospheric sampling program

    NASA Technical Reports Server (NTRS)

    Nyland, T. W.

    1979-01-01

    The condensation-nuclei (Aitken particle) measuring system used in the NASA Global Atmospheric Sampling Program is described. Included in the paper is a description of the condensation-nuclei monitor sensor, the pressurization system, and the Pollack-counter calibration system used to support the CN measurement. The monitor has a measurement range to 1000 CN/cm cubed and a noise level equivalent to 5 CN/cm cubed at flight altitudes between 6 and 13 km.

  7. Pesticides in the atmosphere: a comparison of gas-particle partitioning and particle size distribution of legacy and current-use pesticides

    NASA Astrophysics Data System (ADS)

    Degrendele, C.; Okonski, K.; Melymuk, L.; Landlová, L.; Kukučka, P.; Audy, O.; Kohoutek, J.; Čupr, P.; Klánová, J.

    2016-02-01

    This study presents a comparison of seasonal variation, gas-particle partitioning, and particle-phase size distribution of organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in air. Two years (2012/2013) of weekly air samples were collected at a background site in the Czech Republic using a high-volume air sampler. To study the particle-phase size distribution, air samples were also collected at an urban and rural site in the area of Brno, Czech Republic, using a cascade impactor separating atmospheric particulates according to six size fractions. Major differences were found in the atmospheric distribution of OCPs and CUPs. The atmospheric concentrations of CUPs were driven by agricultural activities while secondary sources such as volatilization from surfaces governed the atmospheric concentrations of OCPs. Moreover, clear differences were observed in gas-particle partitioning; CUP partitioning was influenced by adsorption onto mineral surfaces while OCPs were mainly partitioning to aerosols through absorption. A predictive method for estimating the gas-particle partitioning has been derived and is proposed for polar and non-polar pesticides. Finally, while OCPs and the majority of CUPs were largely found on fine particles, four CUPs (carbendazim, isoproturon, prochloraz, and terbuthylazine) had higher concentrations on coarse particles ( > 3.0 µm), which may be related to the pesticide application technique. This finding is particularly important and should be further investigated given that large particles result in lower risks from inhalation (regardless the toxicity of the pesticide) and lower potential for long-range atmospheric transport.

  8. Phase considerations in the gas/particle partitioning of organic amines in the atmosphere

    NASA Astrophysics Data System (ADS)

    Pankow, James F.

    2015-12-01

    Amines in the atmosphere are of interest because of their likely role in new particle formation, and because of anthropogenic emissions of amines at post-combustion carbon capture (PCCC) facilities. A conceptual framework for considering the partitioning of a monobasic amine (Am = unprotonated, "free-base form") from the gas phase to atmospheric particulate matter (PM) is presented for cases when the PM may be composed of multiple liquid phases. Three types of liquid phases are considered as being individually or simultaneously possible for absorptive uptake of atmospheric amines: w) a mostly water phase; α) a mostly (by mass) organic phase that has at least some polarity (e.g., predominantly secondary organic aerosol (SOA), may contain significant water on a mole fraction basis); and β) a mostly organic phase that is less polar than an α phase (e.g., predominantly primary organic aerosol (POA), containing little water). That one or more salts may contain the aminium ion AmH+ (formed by protonation of Am) is subject to the fact that the trace levels of individual amines in the atmosphere make formation of a pure solid such as AmHHSO4(s) exceedingly unlikely: when solid salts of AmH+ are indeed present, by far the most likely form is as a solid solution, e.g., (NH4+)1-y(AmH+)y HSO4(s)- where y << 1. Neglecting dissolution in solid salts, and considering only partitioning to liquid phases, the overall gas/particle partitioning constant is Kp,tot(m3μg-1) = cp,tot /cg = ∑θfθ Kp,fbθ / αfbθ. The quantity cp,tot (μg μg-1) is the total Am concentration (Am + AmH+) in the PM as summed over all phases using the index θ (= w, α, β); cg is the gas-phase concentration of Am; fθ is the mass fraction of the total PM that is the θ phase; Kp,fbθ is the gas/particle partitioning constant for the free-base (Am) form to the θ phase; and 0 < αfbθ < 1 is the fraction of the amine in the θ phase that is in the free-base form. To date, most treatments of the partitioning of amines to PM have only considered contributions to Kp,tot from absorption into a mostly water phase, according to the term fw Kp,fbw / αfbw. However, unless the PM contains little or no organic-phase material, the α and/or β terms are likely to also be relevant. The Am form of a low MW amine will in general have reasonable affinities for both α and β type phases, so in general Kp,fbw, Kp,fbα, and Kp,fbβ will all be roughly similar in magnitude. And, with significant water uptake into an α phase certain to occur at moderate to high RH values, solvation of ions will often be possible in an α phase. This will assist protonation of Am to AmH+ (as is known to occur for nicotine in tobacco smoke PM). The overall result is that to a first approximation, αfbw and αfbα can be similar in magnitude, making Kp,fb α /αfbα likely to be generally comparable to Kp,fbw / αfbw. In a β phase, ion solvation will not be as good, so that for acidic aerosol αfbβ will generally be closer to one than the other two αfb values, making Kp,fbβ / αfbβ smaller than both Kp,fbw /αfbw and Kp,fbα / αfbα. Overall, modeling of amine behavior in the atmosphere should include consideration of partitioning into organic PM. Unfortunately, this will be more difficult than water-phase only modeling because prediction of αfb values in multiphase PM will be greatly complicated by the needs to: 1) have estimated values of acidity constants in mostly organic phases of variable composition; and 2) allow distribution of chemicals over multiple liquid phases.

  9. Ion precipitation in planetary upper atmospheres: test particle simulations and implications for escape

    NASA Astrophysics Data System (ADS)

    Parkinson, Christopher; Liemohn; Fang, Xiaohua

    A 3-D Monte Carlo energetic particle transport model has been developed and successfully applied to ion precipitation into planetary upper atmospheres in our solar system (viz., Earth, Mars, Jupiter, and Saturn), and can be readily be extended using a full Lorentz motion formu-lation in the absence of strong dipole planetary magnetic fields. This model can be used with a variety of other models to assess the influence of hot ion precipitation on the thermosphere and exosphere of planetary atmospheres and the subsequent sputtering and escape. For instance in the case of Mars, a pick-up ion transport model already exists to allow for particle acceleration exerted by the convection electric field used in conjunction with existing model results from the Mars Thermosphere General Circulation Model (MTGCM) and the BATS-R-US global MHD model. The loss of exospheric neutrals through ionization, in which they become pick-up ions in the solar wind, can be calculated to examine the relative contribution of the various ionization processes. Solar wind protons as well as pick-up ions from a planetary exosphere routinely enter and alter their upper atmosphere. A study of the pick-up ion escape, sputtering, ion-ization, excitation, and energy deposition will be reviewed and discussed, resulting in a robust examination of the influence of energetic ion transport on planetary upper atmospheres.

  10. Development progress of the Materials Analysis and Particle Probe

    NASA Astrophysics Data System (ADS)

    Lucia, M.; Kaita, R.; Majeski, R.; Bedoya, F.; Allain, J. P.; Boyle, D. P.; Schmitt, J. C.; Onge, D. A. St.

    2014-11-01

    The Materials Analysis and Particle Probe (MAPP) is a compact in vacuo surface science diagnostic, designed to provide in situ surface characterization of plasma facing components in a tokamak environment. MAPP has been implemented for operation on the Lithium Tokamak Experiment at Princeton Plasma Physics Laboratory (PPPL), where all control and analysis systems are currently under development for full remote operation. Control systems include vacuum management, instrument power, and translational/rotational probe drive. Analysis systems include onboard Langmuir probes and all components required for x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, direct recoil spectroscopy, and thermal desorption spectroscopy surface analysis techniques.

  11. Development progress of the Materials Analysis and Particle Probe.

    PubMed

    Lucia, M; Kaita, R; Majeski, R; Bedoya, F; Allain, J P; Boyle, D P; Schmitt, J C; Onge, D A St

    2014-11-01

    The Materials Analysis and Particle Probe (MAPP) is a compact in vacuo surface science diagnostic, designed to provide in situ surface characterization of plasma facing components in a tokamak environment. MAPP has been implemented for operation on the Lithium Tokamak Experiment at Princeton Plasma Physics Laboratory (PPPL), where all control and analysis systems are currently under development for full remote operation. Control systems include vacuum management, instrument power, and translational/rotational probe drive. Analysis systems include onboard Langmuir probes and all components required for x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, direct recoil spectroscopy, and thermal desorption spectroscopy surface analysis techniques. PMID:25430248

  12. Development progress of the Materials Analysis and Particle Probe

    SciTech Connect

    Lucia, M. Kaita, R.; Majeski, R.; Boyle, D. P.; Schmitt, J. C.; Onge, D. A. St.; Bedoya, F.; Allain, J. P.

    2014-11-15

    The Materials Analysis and Particle Probe (MAPP) is a compact in vacuo surface science diagnostic, designed to provide in situ surface characterization of plasma facing components in a tokamak environment. MAPP has been implemented for operation on the Lithium Tokamak Experiment at Princeton Plasma Physics Laboratory (PPPL), where all control and analysis systems are currently under development for full remote operation. Control systems include vacuum management, instrument power, and translational/rotational probe drive. Analysis systems include onboard Langmuir probes and all components required for x-ray photoelectron spectroscopy, low-energy ion scattering spectroscopy, direct recoil spectroscopy, and thermal desorption spectroscopy surface analysis techniques.

  13. Force models for particle-dynamics simulations of granular materials

    SciTech Connect

    Walton, O.R.

    1994-12-01

    Engineering-mechanics contact models are utilized to describe the inelastic, frictional interparticle forces acting in dry granular systems. Simple analyses based on one-dimensional chains are utilized to illustrate wave propagation phenomena in dense and dilute discrete particulates. The variation of restitution coefficient with impact velocity is illustrated for a variety of viscous and hysteretic normal force models. The effects of interparticle friction on material strength in discrete-particle simulations are much closer to measured values than are theories that do not allow article rotations.

  14. Sulfur-containing particles emitted by concealed sulfide ore deposits: an unknown source of sulfur-containing particles in the atmosphere

    NASA Astrophysics Data System (ADS)

    Cao, J. J.; Li, Y. K.; Jiang, T.; Hu, G.

    2015-06-01

    Sources of sulfur dioxide, sulfates, and organic sulfur compounds, such as fossil fuels, volcanic eruptions, and animal feeding operations, have attracted considerable attention. In this study, we collected particles carried by geogas flows ascending through soil, geogas flows above the soil that had passed through the soil, and geogas flows ascending through deep faults of concealed sulfide ore deposits, and analysed them using transmission electron microscopy. Numerous crystalline and amorphous sulfur-containing particles or particle aggregations were found in the ascending geogas flows. In addition to S, the particles contained O, Ca, K, Mg, Fe, Na, Pb, Hg, Cu, Zn, As, Ti, Sr, Ba, Si, etc. Such particles are usually a few to several hundred nanometres in diameter with either regular or irregular morphology. The sulfur-containing particles originated from deep-seated weathering or faulting products of concealed sulfide ore deposits. The particles suspended in the ascending geogas flow migrated through faults from deep-seated sources to the atmosphere. This is a previously unknown source of the atmospheric particles. This paper reports, for the first time, the emission of sulfur-containing particles into the atmosphere from concealed sulfide ore deposits. The climatic and ecological influences of these sulfur-containing particles and particle aggregations should be assessed.

  15. Sulfur-containing particles emitted by concealed sulfide ore deposits: an unknown source of sulfur-containing particles in the atmosphere

    NASA Astrophysics Data System (ADS)

    Cao, J.; Li, Y.; Jiang, T.; Hu, G.

    2014-11-01

    Sources of sulfur dioxide, sulfates, and organic sulfur compounds, such as fossil fuels, volcanic eruptions, and animal feeding operations, have attracted considerable attention. In this study, we collected particles carried by geogas flows ascending through soil, geogas flows above the soil that had passed through the soil, and geogas flows ascending through deep faults of concealed sulfide ore deposits and analyzed them using transmission electron microscopy. Numerous crystalline and amorphous sulfur-containing particles or particle aggregations were found in the ascending geogas flows. In addition to S, the particles contained O, Ca, K, Mg, Fe, Na, Pb, Hg, Cu, Zn, As, Ti, Sr, Ba, Si, etc. Such particles are usually a few to several hundred nanometers in diameter with either regular or irregular morphology. The sulfur-containing particles originated from deep-seated weathering or faulting products of concealed sulfide ore deposits. The particles suspended in the ascending geogas flow migrated through faults from deep-seated sources to the atmosphere. This is a previously unknown source of the atmospheric particles. This paper reports, for the first time, the emission of sulfur-containing particles into the atmosphere from concealed sulfide ore deposits. The climatic and ecological influences of these sulfur-containing particles and particle aggregations should to be assessed.

  16. Influence of Particle Phase Morphology on the Hygroscopic Behavior of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Hodas, N.; Zuend, A.; Flagan, R. C.; Seinfeld, J.

    2014-12-01

    While current models generally treat organic and mixed organic-inorganic aerosol particles as well-mixed liquids, these particles can exist in multiple phase states depending on their chemical composition and on ambient conditions such as relative humidity (RH). For example, multi-component particles can undergo phase separations in which an inorganic-electrolyte-rich phase and an organic-rich phase coexist within one particle. Organic aerosols have been shown to exist in an amorphous, highly viscous semi-solid state under atmospherically relevant conditions. Hygroscopic growth factors (GFs) of ten laboratory-generated, organic-inorganic aerosol systems with phase morphologies ranging from well-mixed liquids, to phase-separated particles, to viscous semi-solids were measured with the Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe at RH values ranging from 30 - 90%. Measured GFs were compared to water-uptake calculations in which it was assumed that particles could be represented as thermodynamically ideal, well-mixed liquids, as well as those predicted by the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model. Both ideal and AIOMFAC-predicted GFs were in good agreement with experimental GFs for aerosol systems that exist as well-mixed liquids across the range of RHs tested; however, substantial disagreement between experimental and ideal GFs was observed for phase-separated particles. This disagreement was greatest at low to moderate RHs, whereas experimental GFs approached the ideal curve at high RH as phase-separated particles merged to a single phase with increased water content. AIOMFAC, which offers the ability to predict liquid-liquid and liquid-solid phase separations within a thermodynamic equilibrium computation, was within 10% of experimental GFs at all RHs for all aerosol systems. The assumption that water uptake is driven by ideal, equilibrium partitioning leads to errors in calculated particle size and refractive index and has implications for predicted aerosol scattering efficiencies and radiative properties.

  17. Probing new physics with long-lived charged particles produced by atmospheric and astrophysical neutrinos

    NASA Astrophysics Data System (ADS)

    Ando, Shin'ichiro; Beacom, John F.; Profumo, Stefano; Rainwater, David

    2008-04-01

    As suggested by some extensions of the standard model of particle physics, dark matter may be a super-weakly-interacting lightest stable particle, while the next-to-lightest particle (NLP) is charged and metastable. One could test such a possibility with neutrino telescopes, by detecting the charged NLPs produced in high-energy neutrino collisions with Earth matter. We study the production of charged NLPs by both atmospheric and astrophysical neutrinos; only the latter, which is largely uncertain and has not been detected yet, was the focus of previous studies. We compute the resulting fluxes of the charged NLPs, compare those of different origins and analyze the dependence on the underlying particle physics set-up. We point out that, even if the astrophysical neutrino flux is very small, atmospheric neutrinos, especially those from the prompt decay of charmed mesons, may provide a detectable flux of NLP pairs at neutrino telescopes such as IceCube. We also comment on the flux of charged NLPs expected from proton-nucleon collisions and show that, for theoretically motivated and phenomenologically viable models, it is typically subdominant and below detectable rates.

  18. The inclusion of atmospheric particles into the bark suber of ash trees.

    PubMed

    Catinon, Mickaël; Ayrault, Sophie; Boudouma, Omar; Asta, Juliette; Tissut, Michel; Ravanel, Patrick

    2009-11-01

    A slow deposition of atmospheric components occurs on tree barks. One part of them can be incorporated into bark tissues. This work demonstrates that mineral particles are present inside the suber tissue in four-year-old ash tree stems. Most of these particles are smaller than 2 microm. Scanning electronic microscope studies - using energy dispersive X-ray spectroscopy (SEM-EDX) - on stem cuttings show that they are located either inside the dead suber cells or between these cells. Numerous particles are composed of clay, quartz, feldspar or mica. Others, clearly of anthropogenic origin, are metallic fragments composed of Fe, Ni, Cr, Pb, etc. Spherical fly ashes were found, composed of Si, Al or Fe, and demonstrating an anthropogenic formation. Such particles were isolated and purified from suber ashes obtained at 550 degrees C, after aqueous and acidic treatments, and their composition was established through SEM-EDX. These results reinforce the idea that the suber of tree barks alone can be considered as archives for atmospheric deposition. PMID:19846195

  19. Atmospheric Solids Analysis Probe Mass Spectrometry: A New Approach for Airborne Particle Analysis

    SciTech Connect

    Bruns, Emily A.; Perraud, Veronique M.; Greaves, John; Finlayson-Pitts, Barbara J.

    2010-07-15

    Secondary organic aerosols (SOA) formed in the atmosphere from the condensation of semivolatile oxidation products are a significant component of airborne particles which have deleterious effects on health, visibility, and climate. In this study, atmospheric solids analysis probe mass spectrometry (ASAP-MS) is applied for the first time to the identification of organics in particles from laboratory systems as well as from ambient air. SOA were generated in the laboratory from the ozonolysis of r-pinene and isoprene, as well as from NO3 oxidation of r-pinene, and ambient air was sampled at forested and suburban sites. Particles were collected by impaction on ZnSe disks, analyzed by Fourier transform-infrared spectroscopy (FT-IR) and then transferred to an ASAP-MS probe for further analysis. ASAP-MS data for the laboratory-generated samples show peaks from wellknown products of these reactions, and higher molecular weight oligomers are present in both laboratory and ambient samples. Oligomeric products are shown to be present in the NO3 reaction products for the first time. A major advantage of this technique is that minimal sample preparation is required, and complementary information from nondestructive techniques such as FT-IR can be obtained on the same samples. In addition, a dedicated instrument is not required for particle analysis. This work establishes that ASAP-MS will be useful for identification of organic components of SOA in a variety of field and laboratory studies.

  20. Size-dependent atmospheric deposition and inhalation exposure of particle-bound organophosphate flame retardants.

    PubMed

    Luo, Pei; Bao, Lian-Jun; Guo, Ying; Li, Shao-Meng; Zeng, Eddy Y

    2016-01-15

    Atmospheric size-fractionated particles were collected at different heights in an e-waste recycling zone (QY) and urban Guangzhou (GZ), China and analyzed for organophosphate flame retardants (OPFRs). The total air concentrations of eight OPFRs were 130±130 and 138±127 ng m(-3) in QY and GZ, respectively. Compositional profiles of chlorinated OPFRs were different between QY and GZ, but the size distribution patterns of all OPFRs were not significantly different at different heights. Estimated atmospheric deposition fluxes of OPFRs were 51±67 and 55±13 μg m(-2) d(-1) in QY and GZ, respectively, and the coarse particles (Dp>1.8 μm) dominated both the dry and wet deposition fluxes. Moreover, not all particle-bound OPFRs were inhalable and deposited in the human respiratory tract. The calculated inhalation doses of OPFRs were much lower than the reference doses, suggesting that potential health risk due to inhalation exposure to particle-bound OPFRs in the e-waste recycling zone and urban site was low. PMID:26414926

  1. Probing new physics with long-lived charged particles produced by atmospheric and astrophysical neutrinos

    SciTech Connect

    Ando, Shin'ichiro; Profumo, Stefano; Beacom, John F; Rainwater, David E-mail: beacom@mps.ohio-state.edu E-mail: rain@pas.rochester.edu

    2008-04-15

    As suggested by some extensions of the standard model of particle physics, dark matter may be a super-weakly-interacting lightest stable particle, while the next-to-lightest particle (NLP) is charged and metastable. One could test such a possibility with neutrino telescopes, by detecting the charged NLPs produced in high-energy neutrino collisions with Earth matter. We study the production of charged NLPs by both atmospheric and astrophysical neutrinos; only the latter, which is largely uncertain and has not been detected yet, was the focus of previous studies. We compute the resulting fluxes of the charged NLPs, compare those of different origins and analyze the dependence on the underlying particle physics set-up. We point out that, even if the astrophysical neutrino flux is very small, atmospheric neutrinos, especially those from the prompt decay of charmed mesons, may provide a detectable flux of NLP pairs at neutrino telescopes such as IceCube. We also comment on the flux of charged NLPs expected from proton-nucleon collisions and show that, for theoretically motivated and phenomenologically viable models, it is typically subdominant and below detectable rates.

  2. Novel particle and radiation sources and advanced materials

    NASA Astrophysics Data System (ADS)

    Mako, Frederick

    2016-03-01

    The influence Norman Rostoker had on the lives of those who had the pleasure of knowing him is profound. The skills and knowledge I gained as a graduate student researching collective ion acceleration has fueled a career that has evolved from particle beam physics to include particle and radiation source development and advanced materials research, among many other exciting projects. The graduate research performed on collective ion acceleration was extended by others to form the backbone for laser driven plasma ion acceleration. Several years after graduate school I formed FM Technologies, Inc., (FMT), and later Electron Technologies, Inc. (ETI). Currently, as the founder and president of both FMT and ETI, the Rostoker influence can still be felt. One technology that we developed is a self-bunching RF fed electron gun, called the Micro-Pulse Gun (MPG). The MPG has important applications for RF accelerators and microwave tube technology, specifically clinically improved medical linacs and "green" klystrons. In addition to electron beam and RF source research, knowledge of materials and material interactions gained indirectly in graduate school has blossomed into breakthroughs in materials joining technologies. Most recently, silicon carbide joining technology has been developed that gives robust helium leak tight, high temperature and high strength joints between ceramic-to-ceramic and ceramic-to-metal. This joining technology has the potential to revolutionize the ethylene production, nuclear fuel and solar receiver industries by finally allowing for the practical use of silicon carbide as furnace coils, fuel rods and solar receptors, respectively, which are applications that have been needed for decades.

  3. Light Induced Degradation of Eight Commonly Used Pesticides Adsorbed on Atmospheric Particles: Kinetics and Product Study

    NASA Astrophysics Data System (ADS)

    Socorro, J.; Durand, A.; Gligorovski, S.; Wortham, H.; Quivet, E.

    2014-12-01

    Pesticides are widely used all over the world whether in agricultural production or in non-agricultural settings. They may pose a potential human health effects and environmental risks due to their physico-chemical properties and their extensive use which is growing every year. Pesticides are found in the atmosphere removed from the target area by volatilization or wind erosion, and carried over long distances. These compounds are partitioned between the gaseous and particulate atmospheric phases. The increasingly used pesticides are semi-volatile compounds which are usually adsorbed on the surface of the atmospheric particles. These pesticides may undergo chemical and photo-chemical transformation. New compounds may then be formed that could be more hazardous than the primary pesticides. The atmospheric fate and lifetime of adsorbed pesticides on particles are controlled by the these (photo)chemical processes. However, there is a lack of kinetic data regarding the pesticides in the particle phase. This current work focuses on the photolytic degradation of commonly used pesticides in particulate phase. It aims at estimating the photolytic rates and thus the lifetimes of pesticides adsorbed on silica particles as a proxy of atmospheric particles. The following eight commonly used pesticides, cyprodinil, deltamethrin, difenoconazole, fipronil, oxadiazon, pendimethalin, permethrin, tetraconazole, were chosen because of their physico-chemical properties. The photolysis rates of tetraconazole and permethrin were extremely slow ≤ 1.2 · 10-6 s-1. The photolysis rates for the other pesticides were determined in the range of: (5.9 ± 0.3) · 10-6 < k < (1.7 ± 0.1) · 10-4 s-1 from slowest to the fastest: pendimethalin < cyprodinil < deltamethrin < difenoconazole < oxadiazon < fipronil. Finally, the identification of the surface products upon light irradiation was performed, using GC-(QqQ)-MS/MS and LC-(Q-IMS-ToF)-MS/MS. The potentially formed gas-phase products during these photolysis processes were followed continuously and on-line by PTR-ToF-MS. We hope that the obtained results from this study will help in the development of future environmental strategies to better understand and control phyto-sanitary product application and human exposure.

  4. Gas/particle partitioning of PCDD/F compounds in the atmosphere of Istanbul.

    PubMed

    Saral, Arslan; Gunes, Gulten; Karadeniz, Aykut; Goncaloglu, Bulent Ilhan

    2015-01-01

    Gas/particle partitioning of polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) compounds in the ambient atmosphere were investigated at three different sites (urban-industrial, urban and sub-urban) in İstanbul. Average gas and particle phase concentrations were measured as 133fgm(-3) and 1605fgm(-3), respectively. Gas phase concentrations of polychlorinated dibenzo-p-dioxin/furan (PCDD/F) compounds were determined to be 128fgm(-3), 50fgm(-3), 153fgm(-3) during summer season and 204fgm(-3), 164fgm(-3), 154fgm(-3) during winter season for the respective three sampling sites. Particle phase concentrations were determined to be 287fgm(-3), 176fgm(-3), 160fgm(-3) during summer and 6586fgm(-3), 2570fgm(-3) and 1861fgm(-3) during winter season for those three sampling sites. Chlorination level and molecular weight of congeners affected gas/particle partitioning of PCDD/F compounds. Gas phase percentages of 2,3,7,8-TCDD and OCDD concentrations were determined to be 47% and 1% respectively. A relatively high correlation was found between total particle matter (TPM) and particle phase PCDD/F concentration during winter season. PMID:25290170

  5. Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere.

    PubMed

    Kim, Yong-Ha; Yiacoumi, Sotira; Lee, Ida; McFarlane, Joanna; Tsouris, Costas

    2014-01-01

    Radioactivity can influence surface interactions, but its effects on particle aggregation kinetics have not been included in transport modeling of radioactive particles. In this research, experimental and theoretical studies have been performed to investigate the influence of radioactivity on surface charging and aggregation kinetics of radioactive particles in the atmosphere. Radioactivity-induced charging mechanisms have been investigated at the microscopic level, and heterogeneous surface potential caused by radioactivity is reported. The radioactivity-induced surface charging is highly influenced by several parameters, such as rate and type of radioactive decay. A population balance model, including interparticle forces, has been employed to study the effects of radioactivity on particle aggregation kinetics in air. It has been found that radioactivity can hinder aggregation of particles because of similar surface charging caused by the decay process. Experimental and theoretical studies provide useful insights into the understanding of transport characteristics of radioactive particles emitted from severe nuclear events, such as the recent accident of Fukushima or deliberate explosions of radiological devices. PMID:24308778

  6. EXPERIMENTAL STUDIES ON PARTICLE IMPACTION AND BOUNCE: EFFECTS OF SUBSTRATE DESIGN AND MATERIAL. (R825270)

    EPA Science Inventory

    This paper presents an experimental investigation of the effects of impaction substrate designs and material in reducing particle bounce and reentrainment. Particle collection without coating by using combinations of different impaction substrate designs and surface materials was...

  7. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    SciTech Connect

    farquar, G; Leif, R

    2008-09-12

    Biocompatible polymers with hydrolyzable chemical bonds are being used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres are being produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. The advantages and disadvantages of each method will be presented and discussed in greater detail along with fluorescent and charge properties of the aerosols. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  8. The transmission of differing energy beta particles through various materials

    SciTech Connect

    Quayle, D.R.

    1996-04-01

    The transmission of beta particles is frequently calculated in the same fashion as that of gamma rays, where the mass attenuation coefficient is defined by the slope of the exponential function. Numerous authors have used this approximation including Evans (1955), Loevinger (1952), and Chabot et. al. (1988). Recent work by McCarthy et. al. (1995) indicated that the exponential function seemed to fit well over a particular region of the transmission curve. Upon further investigation, the author decided to verify McCarthy`s results by the use of different absorber materials and attempt to reproduce the experiments. A theoretical method will be used to estimate the transmission of the beta particles through the three absorbers, aluminum, zirconium, and iron. An alternate Monte Carlo code, the Electron Gamma Shower version 4 code (EGS4) will also be used to verify that the experiment is approximating a pencil beam of beta particles. Although these two methods offer a good cross check for the experimental data, they pose a conflict in regards to the type of beam that is to be generated. The experimental lab setup uses a collimated beam of electrons that will impinge upon the absorber, while the codes are written using a pencil beam. A minor discrepancy is expected to be observed in the experimental results and is currently under investigation by McCarthy. The results of this project supported the theory that the beta mass attenuation coefficient was accurately represented by the slope of an exponential function, but only for that particular region of the transmission curve that has a minimal absorber thickness. By fitting the data beyond 50% of the beta particle range this theory does not hold true. The theory generated by McCarthy (1995) and the EGS4 Monte Carlo code indicated that the transmission curve for a pencil beam was not accurately represented by an exponential function. The results of this experiment appeared to provide additional support to this assumption.

  9. Prediction of material strength and fracture of brittle materials using the SPHINX smooth particle hydrodynamics code

    SciTech Connect

    Mandell, D.A.; Wingate, C.A.; Stellingwwerf, R.F.

    1995-12-31

    The design of many devices involves numerical predictions of the material strength and fracture of brittle materials. The materials of interest include ceramics that are used in armor packages; glass that is used in windshields; and rock and concrete that are used in oil wells. As part of a program to develop advanced hydrocode design tools, the authors have implemented a brittle fracture model for glass into the SPHINX smooth particle hydrodynamics code. The authors have evaluated this model and the code by predicting data from tungsten rods impacting glass. Since fractured glass properties, which are needed in the model, are not available, they did sensitivity studies of these properties, as well as sensitivity studies to determine the number of particles needed in the calculations. The numerical results are in good agreement with the data.

  10. In situ measurements of gas/particle-phase transitions for atmospheric semivolatile organic compounds

    PubMed Central

    Williams, Brent J.; Goldstein, Allen H.; Kreisberg, Nathan M.; Hering, Susanne V.

    2010-01-01

    An understanding of the gas/particle-phase partitioning of semivolatile compounds is critical in determining atmospheric aerosol formation processes and growth rates, which in turn affect global climate and human health. The Study of Organic Aerosol at Riverside 2005 campaign was performed to gain a better understanding of the factors responsible for aerosol formation and growth in Riverside, CA, a region with high concentrations of secondary organic aerosol formed through the phase transfer of low-volatility reaction products from the oxidation of precursor gases. We explore the ability of the thermal desorption aerosol gas chromatograph (TAG) to measure gas-to-particle-phase transitioning for several organic compound classes (polar and nonpolar) found in the ambient Riverside atmosphere by using in situ observations of several hundred semivolatile organic compounds. Here we compare TAG measurements to modeled partitioning of select semivolatile organic compounds. Although TAG was not designed to quantify the vapor phase of semivolatile organics, TAG measurements do distinguish when specific compounds are dominantly in the vapor phase, are dominantly in the particle phase, or have both phases present. Because the TAG data are both speciated and time-resolved, this distinction is sufficient to see the transition from vapor to particle phase as a function of carbon number and compound class. Laboratory studies typically measure the phase partitioning of semivolatile organic compounds by using pure compounds or simple mixtures, whereas hourly TAG phase partitioning measurements can be made in the complex mixture of thousands of polar/nonpolar and organic/inorganic compounds found in the atmosphere. PMID:20142511

  11. Chemical Imaging Analysis of Environmental Particles Using the Focused Ion Beam/Scanning Electron Microscopy Technique. Microanalysis Insights into Atmospheric Chemistry of Fly Ash

    SciTech Connect

    Chen, Haihan; Grassian, Vicki H.; Saraf, Laxmikant V.; Laskin, Alexander

    2012-11-08

    Airborne fly ash from coal combustion may represent a source of bioavailable iron (Fe) in the open ocean. However, few studies have been made focusing on Fe speciation and distribution in coal fly ash. In this study, chemical imaging of fly ash has been performed using a dual-beam FIB/SEM (focused ion beam/scanning electron microscope) system for a better understanding of how simulated atmospheric processing modify the morphology, chemical compositions and element distributions of individual particles. A novel approach has been applied for cross-sectioning of fly ash specimen with a FIB in order to explore element distribution within the interior of individual particles. Our results indicate that simulated atmospheric processing causes disintegration of aluminosilicate glass, a dominant material in fly ash particles. Aluminosilicate-phase Fe in the inner core of fly ash particles is more easily mobilized compared with oxide-phase Fe present as surface aggregates on fly ash spheres. Fe release behavior depends strongly on Fe speciation in aerosol particles. The approach for preparation of cross-sectioned specimen described here opens new opportunities for particle microanalysis, particular with respect to inorganic refractive materials like fly ash and mineral dust.

  12. Simulation of cold atmospheric plasma component composition and particle densities in air

    NASA Astrophysics Data System (ADS)

    Kirsanov, Gennady; Chirtsov, Alexander; Kudryavtsev, Anatoliy

    2015-11-01

    Recently discharges in air at atmospheric pressure were the subject of numerous studies. Of particular interest are the cold streams of air plasma, which contains large amounts of chemically active species. It is their action can be decisive in the interaction with living tissues. Therefore, in addition to its physical properties, it is important to know the component composition and particle densities. The goal was to develop a numerical model of atmospheric pressure glow microdischarge in air with the definition of the component composition of plasma. To achieve this goal the task was divided into two sub-tasks, in the first simulated microdischarge atmospheric pressure in air using a simplified set of plasma chemical reactions in order to obtain the basic characteristics of the discharge, which are the initial approximations in the problem of the calculation of the densities with detailed plasma chemistry, including 53 spices and over 600 chemical reactions. As a result of the model was created, which can be adapted for calculating the component composition of plasma of various sources. Calculate the density of particles in the glow microdischarges and dynamics of their change in time.

  13. Simulation of cold atmospheric plasma component composition and particle densities in air

    NASA Astrophysics Data System (ADS)

    Kirsanov, Gennady; Bekasov, Vladimir; Eliseev, Stepan; Kudryavtsev, Anatoly; Sisoev, Sergey

    2015-11-01

    Recently discharges in air at atmospheric pressure were the subject of numerous studies. Of particular interest are the cold streams of air plasma, which contains large amounts of chemically active species. It is their action can be decisive in the interaction with living tissues. Therefore, in addition to its physical properties, it is important to know the component composition and particle densities. The goal was to develop a numerical model of atmospheric pressure glow microdischarge in air with the definition of the component composition of plasma. To achieve this goal the task was broken down into two sub-tasks, in the first simulated microdischarge atmospheric pressure in air using a simplified set of plasma chemical reactions in order to obtain the basic characteristics of the discharge, which are the initial approximations in the problem of the calculation of the densities with detailed plasma chemistry, including 53 spices and over 600 chemical reactions. As a result of the model was created, which can be adapted for calculating the component composition of plasma of various sources. Calculate the density of particles in the glow microdischarges and dynamics of their change in time.

  14. From Clusters to Atmospheric Aerosol Particles: Nucleation in the CLOUD Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Baltensperger, Urs

    2015-03-01

    Globally, a significant source of cloud condensation nuclei for cloud formation is thought to originate from new particle formation (aerosol nucleation). Despite extensive research, many questions remain about the dominant nucleation mechanisms. Specifically, a quantitative understanding of the dependence of the nucleation rate on the concentration of the nucleating substances such as gaseous sulfuric acid, ammonia, water vapor and others has not been reached. This is of relevance for climate as the atmospheric concentrations of sulfuric acid, ammonia and other nucleating agents are strongly influenced by anthropogenic emissions. By providing extremely well controlled and essentially contaminant free conditions in the CLOUD chamber, we were able to show that indeed sulfuric acid is an important component for such new particle formation, however, for the typical temperatures encountered in the planetary boundary layer the concentrations of sulfuric acid are not high enough to explain the atmospheric observations. Moreover, the effect of ammonia, amines and oxidized organic molecules on the nucleation rate of sulfuric acid has been investigated in CLOUD so far. Recent developments in instrument technology such as the Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometer have allowed us to investigate the chemical composition of charged as well as neutral clusters during such nucleation experiments. The CLOUD (Cosmics Leaving OUtdoor Droplets) collaboration consists of 20 institutions from Europe and the United States and is funded by national funding institutions as well as the EU training network CLOUD-TRAIN (http://www.cloud-train.eu/).

  15. Energetic Charged Particle Component or the NO(y) Budget of the Polar Middle Atmosphere

    NASA Technical Reports Server (NTRS)

    Vitt, F. M.; Jackman, C. H.

    1999-01-01

    Analysis of nitrates measured in polar ice cap snow at a high resolution shows large variations in the nitrates. It has been shown that the nitrate signal may contain a signature of solar activity [Zeller and Dreschhoff, 19951. Reactive odd nitrogen production associated with solar particle events (SPEs) and auroral activity may be a source of some of the nitrate anomalies observed in the polar ice caps. Periods of large SPEs can lead to a production of polar atmospheric odd nitrogen in excess of the ambient sources in the polar stratosphere and mesosphere, and may leave a large nitrate signal stratified in the polar ice cap. Auroral electrons and photoelectrons produce odd nitrogen in the thermosphere, some of which may be transported to the polar (>50 degrees) mesosphere and stratosphere. Sources of odd nitrogen in the polar middle atmosphere associated with SPEs, galactic cosmic rays, and auroral electron precipitation have been quantified. The relative contributions by the energetic particles sources to the Noy budget of the polar middle atmosphere (from tropopause to 50 km, from 50 degrees to 90 degrees latitude) are compared with the nitrates observed in the polar ice sheets.

  16. First Steps in Atmospheric Particle Formation: Nucleation of the Smallest Ice Snowflake

    NASA Astrophysics Data System (ADS)

    Lengyel, Jozef; Fedor, Juraj; Kocisek, Jaroslav; Poterya, Viktoriya; Pysanenko, Andriy; Farnik, Michal; Molecular; cluster dynamics Team

    2015-03-01

    The study of atmospheric aerosols attracts a considerable attention because of its influence on atmospheric chemistry and climate. Perhaps the most famous example is the ozone hole where the polar stratospheric clouds play a key role in the ozone depletion process. The atmospheric cloud generation starts with the growing of small ice nanoparticles via uptake of molecules on water clusters. Therefore the cross-sections for uptake have been investigated. The measured cross sections of ice particles can be more than twice larger than the geometrical cross sections of these particles. This can have significant consequences in modelling of growth ice nanoparticles. Subsequently, we have investigated the size-dependence of the measured cross-sections for water clusters. Here, the cross sections of water clusters depart from the theoretically predicted dependence and are considerably larger starting from the clusters of approximately 300 water molecules. We interpret this increase of cross section by the occurrence of highly irregular water cluster shapes, e.g. formation of the ``nanosnowflakes''. Grant agency of the Czech Republic, Grant No. 14-08937S.

  17. Measuring the spectral emissivity of thermal protection materials during atmospheric reentry simulation

    NASA Technical Reports Server (NTRS)

    Marble, Elizabeth

    1996-01-01

    Hypersonic spacecraft reentering the earth's atmosphere encounter extreme heat due to atmospheric friction. Thermal Protection System (TPS) materials shield the craft from this searing heat, which can reach temperatures of 2900 F. Various thermophysical and optical properties of TPS materials are tested at the Johnson Space Center Atmospheric Reentry Materials and Structures Evaluation Facility, which has the capability to simulate critical environmental conditions associated with entry into the earth's atmosphere. Emissivity is an optical property that determines how well a material will reradiate incident heat back into the atmosphere upon reentry, thus protecting the spacecraft from the intense frictional heat. This report describes a method of measuring TPS emissivities using the SR5000 Scanning Spectroradiometer, and includes system characteristics, sample data, and operational procedures developed for arc-jet applications.

  18. In situ measurements of heterogeneous reactions on ambient aerosol particles: Impacts on atmospheric chemistry and climate

    SciTech Connect

    Bertram, Timothy

    2015-02-11

    Aerosol particles play a critical role in the Earth’s energy budget through the absorption and scattering of radiation, and/or through their ability to form clouds and alter cloud lifetime. Heterogeneous and multi-phase reactions alter the climate-relevant properties of aerosol particles and catalyze reaction pathways that are energetically unfavorable in the gas phase. The chemical composition of aerosol particles dictates the kinetics of heterogeneous and multi-phase reactions. At present, the vast majority of the molecular level information on these processes has been determined in laboratory investigations on model aerosol systems. The work described here provides a comprehensive investigation into the reactivity of complex, ambient aerosol particles is proposed to determine: 1) how representative laboratory investigations of heterogeneous and multi-phase processes conducted on model, simple systems are of the real atmosphere, and 2) the impact of heterogeneous and multi-phase processes on ambient particle optical properties and their ability to nucleate clouds. This work has focused on the uptake kinetics for ammonia (NH3) and dinitrogen pentoxide (N2O5). The results of these investigations will be used to directly improve the representation of heterogeneous and multi-phase processes in global climate models, by identifying the key mechanistic drivers that control the variability in the observed kinetics.

  19. Asian dust particles converted into aqueous droplets under remote marine atmospheric conditions

    PubMed Central

    Tobo, Yutaka; Zhang, Daizhou; Matsuki, Atsushi; Iwasaka, Yasunobu

    2010-01-01

    The chemical history of dust particles in the atmosphere is crucial for assessing their impact on both the Earths climate and ecosystem. So far, a number of studies have shown that, in the vicinity of strong anthropogenic emission sources, Ca-rich dust particles can be converted into aqueous droplets mainly by the reaction with gaseous HNO3 to form Ca(NO3)2. Here we show that other similar processes have the potential to be activated under typical remote marine atmospheric conditions. Based on field measurements at several sites in East Asia and thermodynamic predictions, we examined the possibility for the formation of two highly soluble calcium salts, Ca(NO3)2 and CaCl2, which can deliquesce at low relative humidity. According to the results, the conversion of insoluble CaCO3 to Ca(NO3)2 tends to be dominated over urban and industrialized areas of the Asian continent, where the concentrations of HNO3 exceed those of HCl ([HNO3/HCl]>?1). In this regime, CaCl2 is hardly detected from dust particles. However, the generation of CaCl2 becomes detectable around the Japan Islands, where the concentrations of HCl are much higher than those of HNO3 ([HNO3/HCl]particles in dust storms and can play a more important role in forming a deliquescent layer on the particle surfaces as they are transported toward remote ocean regions. PMID:20921372

  20. Nature of the Martian surface as inferred from the particle-size distribution of lunar-surface material.

    NASA Technical Reports Server (NTRS)

    Mason, C. C.

    1971-01-01

    Analysis of lunar particle size distribution data indicates that the surface material is composed of two populations. One population is caused by comminution from the impact of the larger-sized meteorites, while the other population is caused by the melting of fine material by the impact of smaller-sized meteorites. The results are referred to Mars, and it is shown that the Martian atmosphere would vaporize the smaller incoming meteorites and retard the incoming meteorites of intermediate and large size, causing comminution and stirring of the particulate layer. The combination of comminution and stirring would result in fine material being sorted out by the prevailing circulation of the Martian atmosphere and the material being transported to regions where it could be deposited. As a result, the Martian surface in regions of prevailing upward circulation is probably covered by either a rubble layer or by desert pavement; regions of prevailing downward circulation are probably covered by sand dunes.

  1. Proton and alpha particle precipitation onto the upper atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Stenberg Wieser, G.; Ashfaque, M.; Nilsson, H.; Futaana, Y.; Barabash, S.; Diéval, C.; Fedorov, A.; Zhang, T. L.

    2015-08-01

    We study the precipitation of protons and alpha-particles onto the upper atmosphere of Venus, using particle data recorded by the Venus Express spacecraft inside the induced magnetosphere. Our investigations are limited to the dayside close to the terminator. We observe on average a net downward flux of protons, which originate partly from the planetary atmosphere and partly from the solar wind. We present median energy spectra of the precipitating protons divided into two energy ranges, 10-100 eV and 100 eV-30 keV. The total dayside precipitation of solar wind protons is estimated to be 3×1022 s-1, assuming only protons with energies above 500 eV will reach the exobase. Downgoing protons are frequently observed but only in 3% of the available data records we see He2+. These observations are made close to the induced magnetosphere boundary and we argue that at lower altitude the countrates for alpha-particles fall below detection limits. We estimate the precipitation of He2+ onto the dayside exobase to be 1×1021 s-1, which is not enough enough to replace the helium escaping from the planet.

  2. A fast atmospheric turbulent parameters estimation using particle filtering. Application to LIDAR observations

    NASA Astrophysics Data System (ADS)

    Florian, Suzat; Christophe, Baehr; Alain, Dabas

    2011-12-01

    Estimating fast turbulence fluctuations in the boundary layer of the atmosphere, using remote detection instrument is an important scientific issue. Doppler LIDAR, is typically used to get this kind of information because it can make fast, distant, precise, and non-intrusive measurements of the wind field by giving the radial component in any direction. The objective of those measurements is to evaluate as precisely as possible the wind structure using the partial wind information provided, in order to estimate turbulent parameters. The approach presented in this paper, consist in coupling the remote detection system and a stochastic Lagrangian model of the atmosphere. The fluid is represented by a set of interacting particles, evolving according to an evolution system based on S.B Pope work. Data provided by the instrument are assimilated in real time in the model using a particle filtering algorithm. The purpose is to locally correct the properties of particles using measurements, to fit the real fluid observed. A precise real time estimation of the wind field, allows then to estimate turbulent parameters. The methodology has produced convincing results on simulated Doppler LIDAR measurements, in tree-dimensional modeling.

  3. Studying seasonal variations in carbonaceous aerosol particles in the atmosphere over central Siberia

    NASA Astrophysics Data System (ADS)

    Mikhailov, E. F.; Mironova, S. Yu.; Makarova, M. V.; Vlasenko, S. S.; Ryshkevich, T. I.; Panov, A. V.; Andreae, M. O.

    2015-07-01

    The results of 2-year (2010-2012) measurements of the concentrations of organic carbon (OC) and elemental carbon (EC), which were taken at the Zotino Tall Tower Observatory (ZOTTO) Siberian background station (61° N, 89° E), are given. Despite the fact that this station is located far from populated areas and industrial zones, the concentrations of OC and EC in the atmosphere over boreal forests in central Siberia significantly exceed their background values. In winter and fall, high concentrations of atmospheric carbonaceous aerosol particles are caused by the long-range transport (~1000 km) of air masses that accumulate pollutants from large cities located in both southern and southwestern regions of Siberia. In spring and summer, the pollution level is also high due to regional forest fires and agricultural burning in the steppe zone of western Siberia in the Russian-Kazakh border region. Background concentrations of carbonaceous aerosol particles were observed within relatively short time intervals whose total duration was no more than 20% of the entire observation period. In summer, variations in the background concentrations of OC closely correlated with air temperature, which implies that the biogenic sources of organic-particle formation are dominating.

  4. Atmospheric Visibility and PM10 as Indicators of New Particle Formation in an Urban Environment.

    PubMed

    Jayaratne, E R; Clifford, S; Morawska, L

    2015-11-01

    It is well-known that new particle formation (NPF) in the atmosphere is inhibited by pre-existing particles in the air that act as condensation sinks to decrease the concentration and, thus, the supersaturation of precursor gases. In this study, we investigate the effects of two parameters-atmospheric visibility, expressed as the particle backscatter coefficient (BSP), and PM10 particulate mass concentration-on the occurrences of NPF events in an urban environment where the majority of precursor gases originate from motor vehicle and industrial sources. This is the first attempt to derive direct relationships between these two parameters and the occurrence of NPF. NPF events were identified from data obtained with a neutral cluster and air ion spectrometer over 245 days within a calendar year. Bayesian logistic regression was used to determine the probability of observing NPF as functions of BSP and PM10. We show that the BSP at 08 h on a given day is a reliable indicator of an NPF event later that day. The posterior median probability of observing an NPF event was greater than 0.5 (95%) when the BSP at 08 h was less than 6.8 Mm(-1). PMID:26485451

  5. Viscosity of α-pinene secondary organic material and implications for particle growth and reactivity

    SciTech Connect

    Renbaum-Wolff, Lindsay; Grayson, James W.; Bateman, Adam P.; Kuwata, Mikinori; Sellier, Mathieu; Murray, Benjamin J.; Shilling, John E.; Martin, Scot T.; Bertram, Allan K.

    2013-05-14

    Particles composed of secondary organic material (SOM) are abundant in the lower troposphere and play important roles in climate, air quality, and health. The viscosity of these particles is a fundamental property that is presently poorly quantified for conditions relevant to the lower troposphere. Using two new techniques, namely a bead-mobility technique and a poke-flow technique, in conjunction with simulations of fluid flow, we measure the viscosity of the watersoluble component of SOM produced by α-pinene ozonolysis. The viscosity is comparable to that of honey at 90% relative humidity (RH), comparable to that of peanut butter at 70% RH and greater than or comparable to that of bitumen for ≤ 30% RH, implying that the studied SOM ranges from liquid to semisolid/solid at ambient relative humidities. With the Stokes-Einstein relation, the measured viscosities further imply that the growth and evaporation of SOM by the exchange of organic molecules between the gas and condensed phases may be confined to the surface region when RH ≤ 30%, suggesting the importance of an adsorption-type mechanism for partitioning in this regime. By comparison, for RH ≥ 70% partitioning of organic molecules may effectively occur by an absorption mechanism throughout the bulk of the particle. Finally, the net uptake rates of semi-reactive atmospheric oxidants such as O3 are expected to decrease by two to five orders of magnitude for a change in RH from 90% to ≤ 30% RH, with possible implications for the rates of chemical aging of SOM particles in the atmosphere.

  6. The Effect of Particle Size on Iron Solubility in Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Marcotte, A. R.; Majestic, B. J.; Anbar, A. D.; Herckes, P.

    2012-12-01

    The long range transport of mineral dust aerosols, which contain approximately 3% iron by mass, results in an estimated 14-16 Tg of iron deposited into the oceans annually; however, only a small percentage of the deposited iron is soluble. In high-nutrient, low chlorophyll ocean regions iron solubility may limit phytoplankton primary productivity. Although the atmospheric transport processes of mineral dust aerosols have been well studied, the role of particle size has been given little attention. In this work, the effect of particle size on iron solubility in atmospheric aerosols is examined. Iron-containing minerals (illite, kaolinite, magnetite, goethite, red hematite, black hematite, and quartz) were separated into five size fractions (10-2.5, 2.5-1, 1-0.5, 0.5-0.25, and <0.25μm) and extracted into buffer solutions simulating environments in the transport of aerosol particles for 150 minutes. Particle size was confirmed by scanning electron microscopy (SEM). Soluble iron content of the extracted mineral solutions was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Extracted mineral solutions were also analyzed for Fe(II) and Fe(III) content using a ferrozine/UV-VIS method. Preliminary results show that differences in solution composition are more important than differences in size. When extracted into acetate and cloudwater buffers (pH 4.25-4.3), < 0.3% of the Fe in iron oxides (hematite, magnetite, and goethite) is transferred to solution as compared to ~0.1-35% for clays (kaolinite and illite). When extracted into a marine aerosol solution (pH 1.7), the percentage of Fe of the iron oxides and clays transferred to solution increases to approximately 0.5-3% and 5-70%, respectively. However, there is a trend of increased %Fe in the minerals transferred to solution in the largest and smallest size fractions (~0.01-0.3% and ~0.5-35% for iron oxides and clays, respectively), and decreased %Fe in the minerals transferred to solution in the mid-range size fraction (~0.01-0.08% and ~0.1-1% for iron oxides and clays, respectively) when extracted into the acetate and cloudwater buffers. When extracted into the marine aerosol solution the %Fe in the minerals transferred to solution increases with decreasing particle size (from ~0.7% to ~2% and ~10 to 70% in iron oxides and clays, respectively). By examining the role of particle size, this work will provide a more complete understanding of iron dissolution during atmospheric transport of mineral dust aerosols.

  7. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    NASA Astrophysics Data System (ADS)

    Salma, I.; Borsós, T.; Weidinger, T.; Aalto, P.; Hussein, T.; Dal Maso, M.; Kulmala, M.

    2011-02-01

    Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6-1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8 × 103 to 29 ×103 cm-3 with a yearly median of 11.8 × 103 cm-3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79 ± 6)%. Typical diurnal variation of the particle number concentration was related to the major emission patterns in cities, new particle formation, sinks of particles and meteorology. Shapes of the monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. New particle formation and growth unambiguously occurred on 83 days, which represent 27% of all relevant days. Hence, new particle formation and growth are not rare phenomena in Budapest. Their frequency showed an apparent seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. New particle formation events were linked to increased gas-phase H2SO4 concentrations. In the studied area, new particle formation is mainly affected by condensation sink and solar radiation. The formation process seems to be not sensitive to SO2, which was present in a yearly median concentration of 6.7 μg m-3. This suggests that the precursor gas was always available in excess. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm-3 s-1 with a mean and standard deviation of (4.2 ± 2.5) cm-3 s-1. Seasonal dependency for the formation rate could not be identified. Growth curves of nucleated particles were usually superimposed on the characteristic diurnal pattern of road traffic direct emissions. The growth rate of the nucleation mode with a median diameter of 6 nm varied from 2.0 to 13.3 nm h-1 with a mean and standard deviation of (7.7 ± 2.4) nm h-1. There was an indicative tendency for larger growth rates in summer and for smaller values in winter. New particle formation events increased the total number concentration by a mean factor and standard deviation of 2.3 ± 1.1 relative to the concentration that occurred immediately before the event. Several indirect evidences suggest that the new particle formation events occurred at least over the whole city, and were of regional type. The results and conclusions presented are the first information of this kind for the region over one-year long time period.

  8. Particle size distribution of halogenated flame retardants and implications for atmospheric deposition and transport.

    PubMed

    Okonski, Krzysztof; Degrendele, Céline; Melymuk, Lisa; Landlová, Linda; Kukučka, Petr; Vojta, Šimon; Kohoutek, Jiří; Čupr, Pavel; Klánová, Jana

    2014-12-16

    This study investigates the distribution of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD) and a group of novel flame retardants (NFRs) on atmospheric aerosols. Two high volume cascade impactors were used to collect particulate fractions of ambient air over a one year period at urban and rural sites. The majority of FRs were found on the finest aerosols (<0.95 μm). Concentrations of HBCD were higher than those of ΣPBDEs. Moreover, we noted seasonality and spatial differences in particle size distributions, yet a large portion of the observed differences were due to differences in particulate matter (PM) itself. When normalized by PM, the size distributions of the FRs exhibited much greater heterogeneity. Differences existed between the FR distributions by molecular weight, with the higher molecular weight FRs (e.g., BDE-209, Dechlorane Plus) distributed more uniformly across all particulate size fractions. The seasonal, spatial, and compound-specific differences are of crucial importance when estimating dry and wet deposition of FRs as smaller aerosols have longer atmospheric residence times. Estimated wet and dry deposition of four representative FRs (BDE-47, BDE-209, HBCD, and Dechlorane Plus) using size-segregated aerosol data resulted in lower deposition estimates than when bulk aerosol data were used. This has implications for estimates of long-range atmospheric transport and atmospheric residence times, as it suggests that without size-specific distributions, these parameters could be underestimated for FRs. PMID:25380095

  9. Particle excitation, airglow and H2 vibrational disequilibrium in the atmosphere of Jupiter

    SciTech Connect

    Shemansky, D.E.

    1984-09-01

    The extreme ultraviolet EUV emission produced by particle excitation of the hydrogen atmospheres of Jupiter and Saturn is examined using model calculations to determine the nature of the energy deposition process and the effect of such processes on atmospheric structure. Tasks ranging from examination of phenomenologically related processes on Saturn and Titan to analysis of experimental laboratory data required to allow accurate modeling of emissions from hydrogenic atmospheres are investigated. An explanation of the hydrogen H Ly(alpha) bulge in Jupiter's emission from the equatorial region is presented. It is proposed that Saturn, rather than Titan is the major source of the extended hydrogen cloud. The atomic hydrogen detected at the rings of Saturn may originate predominantly from the same source. A cross calibration is obtained between the Pioneer 10 EUV photometer and the Voyager EUV spectrometers, thus providing a direct measure of the temporal morphology of Jupiter between a minimum and a maximum in solar activity. Atomic and molecular data required for the research program are analyzed. An extrapolation of conditions in the upper atmospheres of Jupiter and Saturn produces a predicted condition at Uranus in terms of excitation and hydrogen escape rates that may be observed at Voyager-Uranus encounter.

  10. [Needle-like nonasbestos particles in Bulgarian mineral raw materials].

    PubMed

    Mikhaĭlova-Docheva, L

    1988-01-01

    The spreading of needle-like minerals in the country is studied, which are of no industrial importance, but are contained in some of course and nonmetallic mineral raw materials. On the basis of their classification are chosen standards: sepiolite, wollastonite, palygorskite, etc., and their dispersion in needle-like fine dispersive particles, is studied. On the basis of a preliminary prognosis are established needle-like particles in ore dust of one iron ore location. The importance of the needle-like nonasbestos components can be expressed with "dose" inhaled needles on the basis of the concentration of the needle-like components, the duration of one work shift and the work load in a definite work operation. The quantity of inhaled needles by an operator on a filling machine for mineral flour, containing minimum quantity of needles (0.5%) with pollution above MAC is near to that during packing of asbestos. The results received are useful for future classification of the biological activity of needle-like nonasbestos components. PMID:3241796

  11. Guiding of charged particles through capillaries in insulating materials

    NASA Astrophysics Data System (ADS)

    Stolterfoht, Nikolaus; Yamazaki, Yasunori

    2016-04-01

    Studies of charged particle guiding through capillaries in insulating materials, performed during the last decade, are reviewed in a comprehensive manner. First, the principles of capillary guiding of slow highly charged ions are introduced describing the self-organized formation of charge patches. Basic quantities are defined, such as the guiding power characterizing a capillary. Challenges of the guiding experiments are pointed out. Then, experiments are described with emphasis on the guiding of highly charged ions in the keV energy range. Samples with an array of nanocapillaries as well as single macrocapillaries are treated. Emission profiles of transmitted ions are analyzed to establish scaling laws for the guiding angle, which quantifies the guiding power. Oscillations of the mean ion emission angle reveal the temporal dynamics of the charge patch formation. Next, experiments with ions of high (MeV) energies are focused on single tapered capillaries allowing for the production of a microbeam for various applications. Experiments concerning electrons are presented showing that apart from being elastically scattered these negative particles may enter into the capillary surface where they suffer energy losses. Finally, theoretical concepts of the capillary guiding are discussed. Simulations based on different charge transport methods clearly support the understanding of the guiding mechanisms. Altogether, capillary guiding involves several novel phenomena for which understanding have progressed far beyond their infancy.

  12. Lung cancer mortality and exposure to atmospheric aerosol particles in Guangzhou, China

    NASA Astrophysics Data System (ADS)

    Tie, Xuexi; Wu, Dui; Brasseur, Guy

    In recent years, China and other emerging countries have been experiencing severe air pollution problems with high concentrations of atmospheric aerosol particles. Satellite measurements indicate that the aerosol loading of the atmosphere in highly populated regions of China is about 10 times higher than, for example, in Europe and in the Eastern United States. The exposure to extremely high aerosol concentrations might lead to important human health effects, including respiratory and cardiovascular diseases as well as lung cancers. Here, we analyze 52-year historical surface measurements of haze data in the Chinese city of Guangzhou, and show that the dramatic increase in the occurrence of air pollution events between 1954 and 2006 has been followed by a large enhancement in the incidence of lung cancer.

  13. Correlation of Upper-Atmospheric 7-Be with Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Phillips, G. W.; Share, G. H.; King, S. E.; August, R. A.; Tylka, A. J.; Adams, J. H., Jr.; Panasyuk, M. I.; Nymmik, R. A.; Kuzhevskij, B. M.; Kulikauskas, V. S.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    A surprisingly large concentration of radioactive 7-Be was observed in the upper atmosphere at altitudes above 320 km on the LDEF satellite that was recovered in January 1990. We report on follow-up experiments on Russian spacecraft at altitudes of 167 to 370 km during the period of 1996 to 1999, specifically designed to measure 7-Be concentrations in low earth orbit. Our data show a significant correlation between the 7-Be concentration and the solar energetic proton fluence at Earth, but not with the overall solar activity. During periods of low solar proton fluence, the concentration is correlated with the galactic cosmic ray fluence. This indicates that spallation of atmospheric N by both solar energetic particles and cosmic rays is the primary source of 7-Be in the ionosphere.

  14. Correlation of Upper-Atmospheric Be-7 With Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Phillips, G. W.; Share, G. H.; August, R. A.; Tylka, A. J.; Adams, J. H., Jr.; Panasyuk, M. I.; Nymmik, R. A.; Kuzhevskjj, B. M.; Kulikauskas, V. S.; Rose, M. Franklin (Technical Monitor); Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Surprisingly large concentrations of radioactive Be-7 have been found in the upper atmosphere at levels of one to three orders of magnitude greater than observed in the stratosphere. This phenomenon was originally observed on the LDEF satellite which was recovered in January 1990 following a period of extremely high solar activity in the fall of 1989. We report on follow-up measurements on the Russian COSMOS and RESURS F1 spacecraft during the period of 1996 to 1999 which was a period of minimal to moderate solar activity. The Be-7 concentrations observed on these flights were down substantially from the LDEF observations but were still one to two orders of magnitude higher than stratospheric levels. A significant correlation is observed between the Be-7 activity and the combined fluence of solar energetic protons (SEP) and galactic cosmic-ray (GCR) protons. The Be-7 activity is not correlated with overall solar activity as represented by the solar x-ray flux. We discuss possible mechanisms for the solar proton correlation. However, it is likely that the Be-7 is ionized and it is unknown how this will affect the calculations. There were several large solar flares in the fall of 1989 that produced extraordinarily intense solar particle events at the Earth and record geophysical disturbances. These may have acted to increase production of Be-7 from spallation in the stratosphere and also to enhance transport to higher altitudes from the effects of heating and expansion of the upper atmosphere. Be-7 in the upper atmosphere may also have been produced directly at the Sun. Be-7 and Li-7 are produced in solar flares when accelerated alpha-particles fuse with He-4 in the solar atmosphere. Under optimistic assumptions for Sun to Earth transport and subsequent insertion into low Earth orbit, a Be-7 density of about 10(exp -7) atom/cubic cm at 310 km is estimated.

  15. An improved pulse-height analyzer for energetic particle measurements in the upper atmosphere

    NASA Technical Reports Server (NTRS)

    Dean, L.; Smith, L. G.

    1982-01-01

    An energetic particle spectrometer for measurements in the upper atmosphere by rocket is described. The system has two methods of processing data. One is a staircase generator using threshold detectors; the other is a peak detector. The system incorporates a logarithmic converter for better resolution at low amplitudes and better use of telemetry channels. The circuits are described and calibration procedures are given. Modifications are recommended for high flux environments. Appendices cover sampling error in the peak detector and modifications made to the receiver of the propagation experiment.

  16. Exploring the Origin of High-Energy Particle Beams in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Chilingarian, Ashot A.

    2014-11-01

    High-energy processes in the magnetosphere and atmosphere such as thunderstorm ground enhancements (TGEs), terrestrial gamma ray flashes (TGFs), and transient luminous events (TLEs) and recently discovered relativistic electron acceleration in the Earth's outer radiation belt trigger various dynamic processes in the Earth's environments and have broad astrophysical relevance. Investigation of the accelerated structures in the geospace plasmas can shed light on particle acceleration to much higher energy in the similar structures of space plasmas in the most distant objects in the universe. The Earth's broad environment is a real laboratory for high-energy astrophysics.

  17. Study of individual atmospheric aerosol particles at the Debrecen ion microprobe

    NASA Astrophysics Data System (ADS)

    Kertész, Zs.; Szikszai, Z.; Szoboszlai, Z.; Simon, A.; Huszank, R.; Uzonyi, I.

    2009-06-01

    Aerosol samples collected in outside and indoor environments with a 9-stage PI cascade impactor were analysed using PIXE, STIM (on and off-axis) and RBS ion beam analytical techniques at the Debrecen ion microprobe. Elemental composition, size and morphology of single aerosol particles were determined. Since the quantitative determination of light element concentrations requires a support material with small or no light element content, impactor surfaces made of different materials were tested in order to optimize the sampling and analysis. Thin polymer and Al foils were found to be possibly adequate substrate materials.

  18. Special Issue for the 9th International Conference on Carbonaceous Particles in the Atmosphere

    SciTech Connect

    Strawa, A.W.; Kirchstetter, T.W.; Puxbaum, H.

    2009-12-11

    Carbonaceous particles are a minor constituent of the atmosphere but have a profound effect on air quality, human health, visibility and climate. The importance of carbonaceous particles has been increasingly recognized and become a mainstream topic at numerous conferences. Such was not the case in 1978, when the 1st International Conference on Carbonaceous Particles in the Atmosphere (ICCPA), or ''Carbon Conference'' as it is widely known, was introduced as a new forum to bring together scientists who were just beginning to reveal the importance and complexity of carbonaceous particles in the environment. Table 1 lists the conference dates, venues in the series as well as the proceedings, and special issues resulting form the meetings. Penner and Novakov (Penner and Novakov, 1996) provide an excellent historical perspective to the early ICCPA Conferences. Thirty years later, the ninth in this conference series was held at its inception site, Berkeley, California, attended by 160 scientists from 31 countries, and featuring both new and old themes in 49 oral and 83 poster presentations. Topics covered such areas as historical trends in black carbon aerosol, ambient concentrations, analytic techniques, secondary aerosol formation, biogenic, biomass, and HULIS1 characterization, optical properties, and regional and global climate effects. The conference website, http://iccpa.lbl.gov/, holds the agenda, as well as many presentations, for the 9th ICCPA. The 10th ICCPA is tentatively scheduled for 2011 in Vienna, Austria. The papers in this issue are representative of several of the themes discussed in the conference. Ban-Weiss et al., (Ban-Weiss et al., accepted) measured the abundance of ultrafine particles in a traffic tunnel and found that heavy duty diesel trucks emit at least an order of magnitude more ultrafine particles than light duty gas-powered vehicles per unit of fuel burned. Understanding of this issue is important as ultrafine particles have been shown to adversely affect human health (Lighty et al., 2000; Pope and Dockery, 2006). Gan et al. (Gan et al., accepted) examined the indoor air quality aboard submarines and found that the diesel particulate matter concentrations exceeded the EPA 24 hour standard. Claeys et al. (Claeys et al., accepted) studied the importance and sources of secondary organic aerosol (SOA) in remote marine environment during a period of high biological activity. Methanesulphonate was the major SOA compound detected and there was no evidence for SOA from isoprene. The optical properties of gasoline and diesel vehicle particulate emissions and their relative contribution to radiative forcing was studied by Strawa et al. (Strawa et al., accepted).

  19. The link between atmospheric radicals and newly formed particles at a spruce forest site in Germany

    NASA Astrophysics Data System (ADS)

    Bonn, B.; Bourtsoukidis, E.; Sun, T. S.; Bingemer, H.; Rondo, L.; Javed, U.; Li, J.; Axinte, R.; Li, X.; Brauers, T.; Sonderfeld, H.; Koppmann, R.; Sogachev, A.; Jacobi, S.; Spracklen, D. V.

    2013-10-01

    It has been claimed for more than a century that atmospheric new particle formation is primarily influenced by the presence of sulphuric acid. However, the activation process of sulphuric acid related clusters into detectable particles is still an unresolved topic. In this study we focus on the PARADE campaign measurements conducted during August/September 2011 at Mt. Kleiner Feldberg in central Germany. During this campaign a set of radicals, organic and inorganic compounds and oxidants and aerosol properties were measured or calculated. We compared a range of organic and inorganic nucleation theories, evaluating their ability to simulate measured particle formation rates at 3 nm in diameter (J3) for a variety of different conditions. Nucleation mechanisms involving only sulphuric acid tentatively captured the observed noon-time daily maximum in J3, but displayed an increasing difference to J3 measurements during the rest of the diurnal cycle. Including large organic radicals, i.e. organic peroxy radicals (RO2) deriving from monoterpenes and their oxidation products in the nucleation mechanism improved the correlation between observed and simulated J3. This supports a recently proposed empirical relationship for new particle formation that has been used in global models. However, the best match between theory and measurements for the site of interest was found for an activation process based on large organic peroxy radicals and stabilized Criegee intermediates (sCI). This novel laboratory derived algorithm simulated the daily pattern and intensity of J3 observed in the ambient data. In this algorithm organic derived radicals are involved in activation and growth and link the formation rate of smallest aerosol particles with OH during daytime and NO3 during nighttime. Because of the RO2s lifetime is controlled by HO2 and NO we conclude that peroxy radicals and NO seem to play an important role for ambient radical chemistry not only with respect to oxidation capacity but also for the activation process of new particle formation. This is supposed to have significant impact of atmospheric radical species on aerosol chemistry and should to be taken into account when studying the impact of new particles in climate feedback cycles.

  20. The link between atmospheric radicals and newly formed particles at a spruce forest site in Germany

    NASA Astrophysics Data System (ADS)

    Bonn, B.; Bourtsoukidis, E.; Sun, T. S.; Bingemer, H.; Rondo, L.; Javed, U.; Li, J.; Axinte, R.; Li, X.; Brauers, T.; Sonderfeld, H.; Koppmann, R.; Sogachev, A.; Jacobi, S.; Spracklen, D. V.

    2014-10-01

    It has been claimed for more than a century that atmospheric new particle formation is primarily influenced by the presence of sulfuric acid. However, the activation process of sulfuric acid related clusters into detectable particles is still an unresolved topic. In this study we focus on the PARADE campaign measurements conducted during August/September 2011 at Mt Kleiner Feldberg in central Germany. During this campaign a set of radicals, organic and inorganic compounds and oxidants and aerosol properties were measured or calculated. We compared a range of organic and inorganic nucleation theories, evaluating their ability to simulate measured particle formation rates at 3 nm in diameter (J3) for a variety of different conditions. Nucleation mechanisms involving only sulfuric acid tentatively captured the observed noon-time daily maximum in J3, but displayed an increasing difference to J3 measurements during the rest of the diurnal cycle. Including large organic radicals, i.e. organic peroxy radicals (RO2) deriving from monoterpenes and their oxidation products, in the nucleation mechanism improved the correlation between observed and simulated J3. This supports a recently proposed empirical relationship for new particle formation that has been used in global models. However, the best match between theory and measurements for the site of interest was found for an activation process based on large organic peroxy radicals and stabilised Criegee intermediates (sCI). This novel laboratory-derived algorithm simulated the daily pattern and intensity of J3 observed in the ambient data. In this algorithm organic derived radicals are involved in activation and growth and link the formation rate of smallest aerosol particles with OH during daytime and NO3 during night-time. Because the RO2 lifetime is controlled by HO2 and NO we conclude that peroxy radicals and NO seem to play an important role for ambient radical chemistry not only with respect to oxidation capacity but also for the activation process of new particle formation. This is supposed to have significant impact of atmospheric radical species on aerosol chemistry and should be taken into account when studying the impact of new particles in climate feedback cycles.

  1. COMPASS - COMparative Particle formation in the Atmosphere using portable Simulation chamber Study techniques

    NASA Astrophysics Data System (ADS)

    Bonn, B.; Sun, S.; Haunold, W.; Sitals, R.; van Beesel, E.; dos Santos, L.; Nillius, B.; Jacobi, S.

    2013-12-01

    In this study we report the set-up of a novel twin chamber technique that uses the comparative method and establishes an appropriate connection of atmospheric and laboratory methods to broaden the tools for investigations. It is designed to study the impact of certain parameters and gases on ambient processes, such as particle formation online, and can be applied in a large variety of conditions. The characterisation of both chambers proved that both chambers operate identically, with a residence time xT (COMPASS1) = 26.5 ± 0.3 min and xT (COMPASS2) = 26.6 ± 0.4 min, at a typical flow rate of 15 L min-1 and a gas leak rate of (1.6 ± 0.8) × 10-5 s-1. Particle loss rates were found to be larger (due to the particles' stickiness to the chamber walls), with an extrapolated maximum of 1.8 × 10-3 s-1 at 1 nm, i.e. a hundredfold of the gas leak rate. This latter value is associated with sticky non-volatile gaseous compounds, too. Comparison measurement showed no significant differences. Therefore operation under atmospheric conditions is trustworthy. To indicate the applicability and the benefit of the system, a set of experiments was conducted under different conditions, i.e. urban and remote, enhanced ozone and terpenes as well as reduced sunlight. In order to do so, an ozone lamp was applied to enhance ozone in one of two chambers; the measurement chamber was protected from radiation by a first-aid cover and volatile organic compounds (VOCs) were added using a small additional flow and a temperature-controlled oven. During the elevated ozone period, ambient particle number and volume increased substantially at urban and remote conditions, but by a different intensity. Protection of solar radiation displayed a clear negative effect on particle number, while terpene addition did cause a distinct daily pattern. E.g. adding β pinene particle number concentration rose by 13% maximum at noontime, while no significant effect was observable during darkness. Therefore, the system is a useful tool for investigating local precursors and the details of ambient particle formation at surface locations as well as potential future feedback processes.

  2. On the size and velocity distribution of cosmic dust particles entering the atmosphere

    NASA Astrophysics Data System (ADS)

    Carrillo-Sánchez, J. D.; Plane, J. M. C.; Feng, W.; Nesvorný, D.; Janches, D.

    2015-08-01

    The size and velocity distribution of cosmic dust particles entering the Earth's atmosphere is uncertain. Here we show that the relative concentrations of metal atoms in the upper mesosphere, and the surface accretion rate of cosmic spherules, provide sensitive probes of this distribution. Three cosmic dust models are selected as case studies: two are astronomical models, the first constrained by infrared observations of the Zodiacal Dust Cloud and the second by radar observations of meteor head echoes; the third model is based on measurements made with a spaceborne dust detector. For each model, a Monte Carlo sampling method combined with a chemical ablation model is used to predict the ablation rates of Na, K, Fe, Mg, and Ca above 60 km and cosmic spherule production rate. It appears that a significant fraction of the cosmic dust consists of small (<5 µg) and slow (<15 km s-1) particles.

  3. Exploring Atmospheric Aerosol Chemistry with Advanced High-Resolution Mass Spectrometry and Particle Imaging Methods

    NASA Astrophysics Data System (ADS)

    Nizkorodov, S.

    2014-12-01

    Physical and chemical complexity of atmospheric aerosols presents significant challenges both to experimentalists working on aerosol characterization and to modelers trying to parameterize critical aerosol properties. Multi-modal approaches that combine state-of-the-art experimental, theoretical, and modeling methods are becoming increasingly important in aerosol research. This presentation will discuss recent applications of unique high-resolution mass spectrometry and particle imaging tools developed at two Department of Energy's user facilities, the Environmental Molecular Science Laboratory (EMSL) and Advanced Light Source (ALS), to studies of molecular composition, photochemical aging, and properties of laboratory-generated and field aerosols. Specifically, this presentation will attempt to address the following questions: (a) how do NO2, SO2, and NH3 affect molecular level composition of anthropogenic aerosols?; (b) what factors determine viscosity/surface tension of organic aerosol particles?; (c) how does photolysis affect molecular composition and optical properties of organic aerosols?

  4. Mass and elemental distributions of atmospheric particles nearby blast furnace and electric arc furnace operated industrial areas in Australia.

    PubMed

    Mohiuddin, Kazi; Strezov, Vladimir; Nelson, Peter F; Stelcer, Eduard; Evans, Tim

    2014-07-15

    The improved understanding of mass and elemental distributions of industrial air particles is important due to their heterogeneous atmospheric behaviour and impact on human health and the environment. In this study, particles of different size ranges were collected from three sites in Australia located in the vicinity of iron and steelmaking industries and one urban background site with very little industrial influence. In order to determine the importance of the type of industrial activity on the urban atmospheric quality, the industrial sites selected in this study were in the close proximity to two blast furnace operated and one electric arc furnace based steelmaking sites. The chemical compositions of the collected air particles were analysed using the proton induced X-ray emission (PIXE) technique. This study revealed significantly higher metal concentrations in the atmospheric particles collected in the industrial sites, comparing to the background urban site, demonstrating local influence of the industrial activities to the air quality. The modality types of the particles were found to be variable between the mass and elements, and among elements in the urban and industrial areas indicating that the elemental modal distribution is as important as particle mass for particle pollution modelling. The highest elemental number distribution at all studied sites occurred with particle size of 0.1 μm. Iron was found as the main dominant metal at the industrial atmosphere in each particle size range. The industrial Fe fraction in the submicron and ultrafine size particles was estimated at up to 95% which may be released from high temperature industrial activities with the iron and steelmaking industries being one of the major contributors. Hence, these industrial elemental loadings can highly influence the atmospheric pollution at local urban and regional levels and are required to consider in the atmospheric modelling settings. PMID:24793329

  5. Biological contribution to ice nucleation active particles in clouds at the puy de Dôme atmospheric station, France

    NASA Astrophysics Data System (ADS)

    Amato, Pierre; Joly, Muriel; Deguillaume, Laurent; Delort, Anne-Marie

    2015-04-01

    The distribution, abundance and nature of ice nucleation active particles in the atmosphere are major sources of uncertainty in the prediction of cloud coverage, precipitation patterns and climate. Some biological ice nuclei (IN) induce freezing at temperatures at which most other atmospheric particles exhibit no detectable activity (> -10°C), but their actual contribution to the pool of IN in clouds remains poorly known. In order to help elucidating this, cloud water was collected aseptically from the summit of Puy de Dome (1465m a.s.l., France) within contrasted meteorological and physico-chemical situations. Total and biological (i.e. heat-sensitive) IN were quantified by droplet-freezing assay between -5°C and -14°C. We observed that freezing was systematically induced by biological material, between -6°C and -8°C in 92{%} of the samples. Its removal by heat treatment consistently led to a decrease of the onset freezing temperature, by 3°C or more in most samples. At -10°C, 0 to 220 biological IN mL-1 of cloud water were measured (i.e. 0 to 22 m-3 of cloud air), and these represented 65{%} to 100{%} of the total IN. Based on back-trajectories and on physico-chemical analyses, the high variability observed resulted probably from a source effect, with IN originating mostly from continental sources. Bacteria concentration in the air at altitude relevant for clouds typically ranges from ˜102 to ˜105 cells m-3. Assuming that biological IN measured in cloud water samples at -8°C were all bacteria, ice nucleation active bacteria represented at maximum 0.6{%} of the total bacteria cells present (3.1{%} at -12°C). These results should help elucidating the role of biological and bacterial IN on cloud microphysics and their impact on precipitation at local scale. References: Joly, M., Amato, P., Deguillaume, L., Monier, M., Hoose, C., and Delort A-M (2014). Quantification of ice nuclei active at near 0°C temperatures in low altitude clouds at the puy de Dome atmospheric station. Atmospheric Chemistry and Physics 14, 8185-8195. Joly, M., Attard, E., Sancelme, M., Deguillaume, L., Guilbaud, C., Morris, C., Amato, P. and Delort A-M (2013). Ice nucleation activity of bacteria isolated from cloud water. Atmospheric Environment 70, 392-400.

  6. Growth of atmospheric nano-particles by heterogeneous nucleation of organic vapor

    NASA Astrophysics Data System (ADS)

    Wang, J.; McGraw, R. L.; Kuang, C.

    2013-07-01

    Atmospheric aerosols play critical roles in air quality, public health, and visibility. In addition, they strongly influence climate by scattering solar radiation and by changing the reflectivity and lifetime of clouds. One major but still poorly understood source of atmospheric aerosols is new particle formation, which consists of the formation of thermodynamically stable clusters from trace gas molecules (homogeneous nucleation) followed by growth of these clusters to a detectable size (~3 nm). Because freshly nucleated clusters are most susceptible to loss due to high rate of coagulation with pre-existing aerosol population, the initial growth rate strongly influences the rate of new particle formation and ambient aerosol population. Whereas many field observations and modeling studies indicate that organics enhance the initial growth of the clusters and therefore new particle formation, thermodynamic considerations would suggest that the strong increase of equilibrium vapor concentration due to cluster surface curvature (Kelvin effect) may prevent ambient organics from condensing on these small clusters. Here, the contribution of organics to the initial cluster growth is described as heterogeneous nucleation of organic molecules onto these clusters. We find that the strong gradient in cluster population with respect to its size leads to positive cluster number flux. This positive flux drives the growth of clusters substantially smaller than the Kelvin diameter, conventionally considered the minimum particle size that can be grown through condensation. The conventional approach neglects the contribution from the cluster concentration gradient, and underestimates the cluster survival probabilities by a factor of up to 60 if early growth of clusters is due to both condensation of sulfuric acid and heterogeneous nucleation of organic vapors.

  7. Carbohydrate-like composition of submicron atmospheric particles and their production from ocean bubble bursting

    PubMed Central

    Russell, Lynn M.; Hawkins, Lelia N.; Frossard, Amanda A.; Quinn, Patricia K.; Bates, Tim S.

    2010-01-01

    Oceans cover over two-thirds of the Earth’s surface, and the particles emitted to the atmosphere by waves breaking on sea surfaces provide an important contribution to the planetary albedo. During the International Chemistry Experiment in the Arctic LOwer Troposphere (ICEALOT) cruise on the R/V Knorr in March and April of 2008, organic mass accounted for 15–47% of the submicron particle mass in the air masses sampled over the North Atlantic and Arctic Oceans. A majority of this organic component (0.1 - 0.4 μ m-3) consisted of organic hydroxyl (including polyol and other alcohol) groups characteristic of saccharides, similar to biogenic carbohydrates found in seawater. The large fraction of organic hydroxyl groups measured during ICEALOT in submicron atmospheric aerosol exceeded those measured in most previous campaigns but were similar to particles in marine air masses in the open ocean (Southeast Pacific Ocean) and coastal sites at northern Alaska (Barrow) and northeastern North America (Appledore Island and Chebogue Point). The ocean-derived organic hydroxyl mass concentration during ICEALOT correlated strongly to submicron Na concentration and wind speed. The observed submicron particle ratios of marine organic mass to Na were enriched by factors of ∼102–∼103 over reported sea surface organic to Na ratios, suggesting that the surface-controlled process of film bursting is influenced by the dissolved organic components present in the sea surface microlayer. Both marine organic components and Na increased with increasing number mean diameter of the accumulation mode, suggesting a possible link between organic components in the ocean surface and aerosol–cloud interactions. PMID:20080571

  8. Long-term observations of new particle formation in Eastern Mediterranean atmosphere

    NASA Astrophysics Data System (ADS)

    Kalivitis, Nikolaos; Kouvarakis, Giorgos; Bougiatioti, Aikaterini; Stavroulas, Iasonas; Manninen, Hanna E.; Kulmala, Markku; Kerminen, Veli-Matti; Mihalopoulos, Nikolaos

    2015-04-01

    New particle formation (NPF) is a frequent phenomenon in the marine boundary layer (MBL) atmosphere. So far, for the Mediterranean region, NPF events have been reported in the literature but this is the first time that long-term continuous measurements are used to identify and characterize NPF events. We analyzed continuous measurements from the environmental research station of University of Crete at Finokalia, Crete, Greece (35° 20' N, 25° 40' E, 250m a.s.l). The site has been reported to be representative for the eastern Mediterranean MBL atmosphere. Number size distributions of particles in the size range 8 to 848 nm were measured using scanning mobility particle sizer (SMPS) since 2008 (with additional data available for 2004 and 2005 ). Particle growth rates up to the diameter of 25 nm were calculated as well as the condensational sink Additionally, mobility distributions of air ions were measured using an Air Ion Spectrometer (AIS) in the mobility range between 3.2 and 0.0013 cm2V-1s-1 (0.8-42 nm ) for the periods April 2008-April 2009 and December 2012-December 2013. During the NPF event days, the formation and growth rates of sub-3 nm ions could be calculated from AIS data. We found for the Eastern Mediterranean MBL, 22% of the available days could be identified as event days. Although Finokalia is a sub-tropical site with intense photochemistry leading to the production of high concentrations of sulfuric acid, the necessary compound for triggering atmospheric nucleation, NPF at Finokalia has been found to be less frequent than in other locations across Europe. However, NPF takes place all year long indicating that the necessary precursors are available throughout the year. The probability of an event to take place was greatly dependent on the condensational sink, which was two times lower on event than non-event days. The growth rates of the fresh particles presented an annual cycle with maximum values in summer and the average growth rate to 25 nm for all the events was 4.9 ±0.7 nm h-1. Using air ion mobility distributions for the two periods we calculated average growth rate of 2.9 nm h-1 for the diameters 1.5 -3 nm.

  9. Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules

    PubMed Central

    Schobesberger, Siegfried; Junninen, Heikki; Bianchi, Federico; Lönn, Gustaf; Ehn, Mikael; Lehtipalo, Katrianne; Dommen, Josef; Ehrhart, Sebastian; Ortega, Ismael K.; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Hutterli, Manuel; Duplissy, Jonathan; Almeida, João; Amorim, Antonio; Breitenlechner, Martin; Downard, Andrew J.; Dunne, Eimear M.; Flagan, Richard C.; Kajos, Maija; Keskinen, Helmi; Kirkby, Jasper; Kupc, Agnieszka; Kürten, Andreas; Kurtén, Theo; Laaksonen, Ari; Mathot, Serge; Onnela, Antti; Praplan, Arnaud P.; Rondo, Linda; Santos, Filipe D.; Schallhart, Simon; Schnitzhofer, Ralf; Sipilä, Mikko; Tomé, António; Tsagkogeorgas, Georgios; Vehkamäki, Hanna; Wimmer, Daniela; Baltensperger, Urs; Carslaw, Kenneth S.; Curtius, Joachim; Hansel, Armin; Petäjä, Tuukka; Kulmala, Markku; Donahue, Neil M.; Worsnop, Douglas R.

    2013-01-01

    Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research. The experiments involved sulfuric acid vapor and different stabilizing species, including ammonia and dimethylamine, as well as oxidation products of pinanediol, a surrogate for organic vapors formed from monoterpenes. A striking resemblance is revealed between the mass spectra from the chamber experiments with oxidized organics and ambient data obtained during new particle formation events at the Hyytiälä boreal forest research station. We observe that large oxidized organic compounds, arising from the oxidation of monoterpenes, cluster directly with single sulfuric acid molecules and then form growing clusters of one to three sulfuric acid molecules plus one to four oxidized organics. Most of these organic compounds retain 10 carbon atoms, and some of them are remarkably highly oxidized (oxygen-to-carbon ratios up to 1.2). The average degree of oxygenation of the organic compounds decreases while the clusters are growing. Our measurements therefore connect oxidized organics directly, and in detail, with the very first steps of new particle formation and their growth between 1 and 2 nm in a controlled environment. Thus, they confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions. PMID:24101502

  10. Atmospheric Particle Size Distributions in the Spanish Network of Environmental DMAs (REDMAAS)

    NASA Astrophysics Data System (ADS)

    Alonso-Blanco, E.; Gómez-Moreno, F. J.; Artíñano, B.; Iglesias Samitier, S.; Juncal, V.; Piñeiro Iglesias, M.; López Mahía, P.; Pérez, N.; Brines, M.; Alastuey, A.; Querol, X.; de la Morena, B. A.; García, M. I.; Rodríguez, S.; Sorribas, M.; Titos, G.; Lyamani, H.; Alados-Arboledas, L.

    2015-12-01

    The present work is a first approach to the study of the spatio-temporal variability of the submicrometer atmospheric aerosol in Spain. The aerosol measurements have been obtained simultaneously at seven monitoring stations that compose the REDMAAS network during two measurement campaigns corresponding to summer and winter seasons. In both summer and winter periods those measurement stations with a direct influence of anthropogenic emissions recorded the highest concentrations of particle number. In the summer campaign, the average daily pattern of the aerosol size distribution in the traffic and background urban stations was conditioned by the traffic emissions and secondary aerosol formation through photochemical reactions (new particle formation events, NPF). However, the secondary aerosol had a higher contribution to the aerosol total number concentration in the rural background and high-altitude stations. In the winter campaign, in all sampling sites with the exception of Izaña station, the traffic and domestic activity emissions had a greater contribution than secondary aerosol formation on particle number total concentration. New particle formation events were identified at all sites during the summer period, and at sites without direct influence of anthropogenic emissions during the winter campaign. Some aerosol shrinkage processes were also observed at the Madrid and El Arenosillo stations.

  11. Advanced Process Technology: Combi Materials Science and Atmospheric Processing (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet for the National Center for Photovoltaics: Process Technology and Advanced Concepts -- High-Throughput Combi Material Science and Atmospheric Processing that includes scope, core competencies and capabilities, and contact/web information.

  12. Particle Induced X-Ray Emission Analysis of Atmospheric Aerosols Collected in Upstate New York

    NASA Astrophysics Data System (ADS)

    Gleason, Colin; Harrington, Charles; Schuff, Katie; Labrake, Scott; Vineyard, Michael

    2009-10-01

    Elemental analysis of atmospheric aerosols collected in the historic Stockade District of Schenectady, New York, was performed using particle induced X-ray emission (PIXE) spectroscopy. This is part of a systematic study in the Mohawk River Valley of upstate New York to identify the sources and understand the transport, transformation, and effects of airborne pollutants and the connection between aerosols, the deposition of pollution, and the uptake of pollutants by wildlife and vegetation. The atmospheric aerosols were collected with a nine-stage cascade impactor that allows for the analysis of the particulate matter as a function of particle size. The samples were bombarded with 2-MeV proton beams from the Union College Pelletron Accelerator and the energy spectra of the X-rays were measured with a silicon drift detector. The X-ray spectra were analyzed using GUPIX software to extract the elemental concentrations of the particulate matter. The sample collection and analysis will be described, and preliminary results will be presented.

  13. Recent impacts of energetic particle precipitation on the Earth's middle atmosphere

    NASA Astrophysics Data System (ADS)

    Randall, C. E.

    2005-05-01

    The extraordinary solar storms of October-November 2003 have now received much attention in the literature, and it is well-known that the associated energetic particles caused immediate production of HOx and NOx in the upper stratosphere and mesosphere that led to significant ozone depletion. Less obvious is whether unprecedented enhancements in stratospheric NOx and concurrent reductions in ozone several months following the storms were a direct result of the storms themselves, or of energetic particle precipitation later in the winter. Complicating the picture is the fact that the late winter upper stratospheric polar vortex in 2004 was stronger than previously observed since records began (1979). Insight to this dilemma can be gained by comparison of atmospheric effects after other periods of high geomagnetic activity, and in both hemispheres. Using satellite data and modeling, this presentation will compare and contrast the response of the middle atmosphere after several different periods of high geomagnetic activity in recent years. Emphasis will be placed on understanding the effects after the late 2003 storms in the context of storms that occurred at similar times of year relative to the northern and southern hemispheres; this will include, for instance, the solar proton events of October 1989 and November 2000 and 2001, and the solar storms of April 2002.

  14. Soft materials design via self assembly of functionalized icosahedral particles

    NASA Astrophysics Data System (ADS)

    Muthukumar, Vidyalakshmi Chockalingam

    In this work we simulate self assembly of icosahedral building blocks using a coarse grained model of the icosahedral capsid of virus 1m1c. With significant advancements in site-directed functionalization of these macromolecules [1], we propose possible application of such self-assembled materials for drug delivery. While there have been some reports on organization of viral particles in solution through functionalization, exploiting this behaviour for obtaining well-ordered stoichiometric structures has not yet been explored. Our work is in well agreement with the earlier simulation studies of icosahedral gold nanocrystals, giving chain like patterns [5] and also broadly in agreement with the wet lab works of Finn, M.G. et al., who have shown small predominantly chain-like aggregates with mannose-decorated Cowpea Mosaic Virus (CPMV) [22] and small two dimensional aggregates with oligonucleotide functionalization on the CPMV capsid [1]. To quantify the results of our Coarse Grained Molecular Dynamics Simulations I developed analysis routines in MATLAB using which we found the most preferable nearest neighbour distances (from the radial distribution function (RDF) calculations) for different lengths of the functional groups and under different implicit solvent conditions, and the most frequent coordination number for a virus particle (histogram plots further using the information from RDF). Visual inspection suggests that our results most likely span the low temperature limits explored in the works of Finn, M.G. et al., and show a good degree of agreement with the experimental results in [1] at an annealing temperature of 4°C. Our work also reveals the possibility of novel stoichiometric N-mer type aggregates which could be synthesized using these capsids with appropriate functionalization and solvent conditions.

  15. Interplanetary dust particles collected in the stratosphere - Observations of atmospheric heating and constraints on their interrelationships and sources

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Bradley, John P.

    1989-01-01

    TEM and IR spectroscopy investigations of the interplanetary dust particles (IDPs) collected in the stratosphere have shown the majority of IDPs in the layer-lattice silicate and pyroxene classes to not have been heated to temperatures above 600 C during atmospheric entry. This implies that they arrive at the upper atmosphere with low geocentric encounter velocities, and limits the possible encounter trajectories for these particles to relatively circular prograde orbits. On this basis, it is judged unlikely that these IDPs are from earth-crossing comets or asteroids; collected IDPs dominated by olivine include a larger portion of above-600 C-heated particles, suggesting their capture from more eccentric orbits.

  16. Evaluation of the atmospheric transport of marine-derived particles using long-chain unsaturated ketones

    SciTech Connect

    Sicre, M.A.; Gagosian, R.B.; Peltzer, E.T. )

    1990-02-20

    Biomarker source information provided by long-chain alkenone (LCA) distribution patterns was used to assess the transport pathways of marine aerosols. The C{sub 37}-C{sub 39}LCA were found in significant amounts in aerosols collected in New Zealand. Their occurrence in the atmosphere stems from their introduction by bubble-bursting processes during wave breaking. The surface water temperatures calculated from the U{sub 37}{sup k} ratios suggested a local origin and short atmospheric residence times of the LCA. They were not detected in aerosol samples collected on American Samoa due to the absence of the source organisms in surface waters. The distribution of LCA was also investigated in size-fractionated aerosols over a range of < 0.5 to > 7.2 {mu}m equivalent diameter. Their distribution over the size spectrum demonstrated that they were only associated with large particles (d{sub eq} > 3.0 {mu}m), suggesting a direct injection of algal cells and/or their fragments into the atmosphere.

  17. Particle-in-Cell Simulations of Atmospheric Pressure He/2%H2O Discharges

    NASA Astrophysics Data System (ADS)

    Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J.; Graves, D. B.; Gopalakrishnan, R.

    2015-09-01

    Atmospheric pressure micro-discharges in contact with liquid surfaces are of increasing interest, especially in the bio-medical field. We conduct 1D3v particle-in-cell (PIC) simulations of a voltage-driven 1 mm width atmospheric pressure He/2% H2O plasma discharge in series with an 0.5 mm width liquid H2O layer and a 1mm width quartz dielectric layer. A previously developed two-temperature hybrid global model of atmospheric pressure He/H2O discharges was used to determine the most important species and collisional reactions to use in the PIC simulations. We found that H13O6+, H5O3-, and electrons were the most prominent charged species, while most of the metastable helium He* was quenched via Penning ionization. The ion-induced secondary emission coefficient γi was assumed to be 0.15 at all surfaces. A series of simulations were conducted at 27.12 MHz with Jrf ~ 800-2200 A/m2. The H2O rotational and vibrational excitation losses were so high that electrons reached the walls at thermal temperatures. We also simulated a much lower frequency case of 50 kHz with Vrf = 10 kV. In this case, the discharge ran in a pure time-varying γ-mode. This work was supported by the Department of Energy Office of Fusion Energy Science Contract DE-SC0001939.

  18. Comparison of isolation and quantification methods to measure humic-like substances (HULIS) in atmospheric particles

    NASA Astrophysics Data System (ADS)

    Fan, Xingjun; Song, Jianzhong; Peng, Ping'an

    2012-12-01

    Humic-like Substances (HULIS) comprise a significant fraction of the water-soluble organic aerosol mass and influence the cloud microphysical properties and climate effects of aerosols in the atmosphere. In this work, the most frequently used HULIS isolation and quantification methods including ENVI-18, HLB, XAD-8 and DEAE were comparatively characterized with two model standards, ten interfering compounds, and five ambient aerosol samples. Quantification of HULIS is performed with a TOC analyzer, complemented by an investigation of the chemical structure of the extracted fractions by UV-Vis spectroscopy. The results show that the four isolation methods were all characterized by high reliability, high reproducibility, and low limit of detection (LOD), indicating that each method can be used to efficiently recover Suwannee River Fulvic Acid (SRFA) and be applied to the quantification of the lower amount of HULIS in atmospheric particles. The analytical results of the UV-Vis spectra of HULIS fractions isolated also indicate that they are all favorable for extraction of compounds of high UV absorbance, high MW, and high aromaticity and that the DEAE protocol is the most significant one. Compared with the DEAE method that favors extraction of highly UV-absorbing and more aromatic compounds, SRFA isolated by the ENVI-18, HLB, and XAD-8 protocols were more representative of the global matrix. Each method has its own advantages and disadvantages and is suitable for a particular application. No single method is ideal for both isolation and quantification of HULIS in atmospheric samples.

  19. The effect of atmospheric aerosol particles and clouds on net ecosystem exchange in the Amazon

    NASA Astrophysics Data System (ADS)

    Cirino, G. G.; Souza, R. A. F.; Adams, D. K.; Artaxo, P.

    2014-07-01

    Carbon cycling in the Amazon is closely linked to atmospheric processes and climate in the region as a consequence of the strong coupling between the atmosphere and biosphere. This work examines the effects of changes in net radiation due to atmospheric aerosol particles and clouds on the net ecosystem exchange (NEE) of CO2 in the Amazon region. Some of the major environmental factors affecting the photosynthetic activity of plants, such as air temperature and relative humidity, were also examined. An algorithm for clear-sky irradiance was developed and used to determine the relative irradiance, f, which quantifies the percentage of solar radiation absorbed and scattered due to atmospheric aerosol particles and clouds. Aerosol optical depth (AOD) was calculated from irradiances measured with the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor, onboard the Terra and Aqua satellites, and was validated with ground-based AOD measurements from AERONET (Aerosol Robotic Network) sun photometers. Carbon fluxes were measured using eddy covariance technique at the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) flux towers. Two sites were studied: the Jaru Biological Reserve (RBJ), located in Rondonia, and the Cuieiras Biological Reserve at the K34 LBA tower (located in a preserved region in the central Amazon). Analysis was performed continuously from 1999 to 2009 at K34 and from 1999 to 2002 at RBJ, and includes wet, dry and transition seasons. In the Jaru Biological Reserve, a 29% increase in carbon uptake (NEE) was observed when the AOD ranged from 0.10 to 1.5 at 550 nm. In the Cuieiras Biological Reserve, the aerosol effect on NEE was smaller, accounting for an approximate 20% increase in NEE. High aerosol loading (AOD above 3 at 550 nm) or high cloud cover leads to reductions in solar flux and strong decreases in photosynthesis up to the point where NEE approaches zero. The observed increase in NEE is attributed to an enhancement (~50%) in the diffuse fraction of photosynthetic active radiation (PAR). The enhancement in diffuse PAR can be done through increases in aerosols and/or clouds. In the present study, it was not possible to separate these two components. Significant changes in air temperature and relative humidity resulting from changes in solar radiation fluxes under high aerosol loading were also observed at both sites. Considering the long-range transport of aerosols in the Amazon, the observed changes in NEE for these two sites may occur over large areas in the Amazon, significantly altering the carbon balance in the largest rainforest in the world.

  20. The effect of atmospheric aerosol particles and clouds on Net Ecosystem Exchange in Amazonia

    NASA Astrophysics Data System (ADS)

    Cirino, G. G.; Souza, R. F.; Adams, D. K.; Artaxo, P.

    2013-11-01

    Carbon cycling in Amazonia is closely linked to atmospheric processes and climate in the region as a consequence of the strong coupling between the atmosphere and biosphere. This work examines the effects of changes in net radiation due to atmospheric aerosol particles and clouds on the Net Ecosystem Exchange (NEE) of CO2 in the Amazon region. Some of the major environmental factors affecting the photosynthetic activity of plants, such as air temperature and relative humidity were also examined. An algorithm for clear-sky irradiance was developed and used to determine the relative irradiance f, which quantifies the percentage of solar radiation absorbed and scattered due to atmospheric aerosol particles and clouds. Aerosol optical depth (AOD) was calculated from irradiances measured with the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor, onboard the TERRA and AQUA satellites, and was validated with ground-based AOD measurements from AERONET sun photometers. Carbon fluxes were measured using eddy-correlation techniques at LBA (The Large Scale Biosphere-Atmosphere Experiment in Amazonia) flux towers. Two sites were studied: the Biological Reserve of Jaru (located in Rondonia) and the Cuieiras Biological Reserve (located in a preserved region in central Amazonia). In the Jaru Biological Reserve, a 29% increase in carbon uptake (NEE) was observed when the AOD ranged from 0.10 to 1.5. In the Cuieiras Biological Reserve, this effect was smaller, accounting for an approximately 20% increase in NEE. High aerosol loading (AOD above 3 at 550 nm) or cloud cover leads to reductions in solar flux and strong decreases in photosynthesis up to the point where NEE approaches 0. The observed increase in NEE is attributed to an enhancement (~50%) in the diffuse fraction of photosynthetic active radiation (PAR). Significant changes in air temperature and relative humidity resulting from changes in solar radiation fluxes under high aerosol loading were also observed at both sites. Considering the long-range transport of aerosols in Amazonia, the observed changes in NEE for these two sites may occur over large areas in Amazonia, significantly altering the carbon balance in the largest rainforest of the world.

  1. Quantitative characterization of the spatial distribution of particles in materials: Application to materials processing

    NASA Technical Reports Server (NTRS)

    Parse, Joseph B.; Wert, J. A.

    1991-01-01

    Inhomogeneities in the spatial distribution of second phase particles in engineering materials are known to affect certain mechanical properties. Progress in this area has been hampered by the lack of a convenient method for quantitative description of the spatial distribution of the second phase. This study intends to develop a broadly applicable method for the quantitative analysis and description of the spatial distribution of second phase particles. The method was designed to operate on a desktop computer. The Dirichlet tessellation technique (geometrical method for dividing an area containing an array of points into a set of polygons uniquely associated with the individual particles) was selected as the basis of an analysis technique implemented on a PC. This technique is being applied to the production of Al sheet by PM processing methods; vacuum hot pressing, forging, and rolling. The effect of varying hot working parameters on the spatial distribution of aluminum oxide particles in consolidated sheet is being studied. Changes in distributions of properties such as through-thickness near-neighbor distance correlate with hot-working reduction.

  2. Retrieving of Microphysical Properties of Spheroidal Particles in the Atmosphere-Surface System

    NASA Astrophysics Data System (ADS)

    Korkin, S.; Lyapustin, A.

    2013-12-01

    In this presentation, we continue our study of the Levenberg-Marquardt algorithm [1, 2] as a tool for retrieval of properties of particles, suspended in the plane-parallel atmosphere coupled with the reflecting surface [3]. The effect of polarization of light is included. The Levenberg-Marquardt algorithm provides an iterative solution to the problem of minimization of a function over a space of its parameters. Each iteration involves solution of the forward problem and computation of the Jacobian matrix (the derivatives of signal over optical parameters). The recently developed code APC (Atmospheric Polarization Computations) is used to solve the forward problem [4, 5]. We use O.Dubovik's et al. [6] package to simulate scattering by spheroidal particles. Unlike for the purely spherical particles (Mie scattering), the Jacobian matrix for spheroids is computed numerically. We will consider retrievals over the land and the ocean with the bidirectional polarization distribution functions from [7-8]. Using MISR observation geometry and spectral bands [9] as an example, we will discuss the problem of convergence of iterations, sensitivity of the algorithm to the initial guess, the signal-to-noise ratio, and the geometry of observation. Possible ways of acceleration of iterations will be discussed, as well as the role of polarization in the retrieval process. References: 1. Levenberg K, Q. App. Math., 1944, V.2, P.164. 2. Marquardt D, J. Appl. Math., 1963, V.11, N.2, P.431. 3. Korkin S, Lyapustin A, AGU 2012, A23A-011. 4. Korkin S et al., JQSRT, 2013, V.127, P.1 5. ftp://climate1.gsfc.nasa.gov/skorkin/ 6. Dubovik O et al., Geophys. Res. Letters, 2006, V.111, D11208. 7. Ota Y, et al., JQSRT, 2010, V.111, P.878. 8. Nadal F, Breon F-M, IEEE Trans. Geos. Rem. Sens., 1999, V.37, N.3, P.1709. 9. http://www-misr.jpl.nasa.gov/Mission/misrInstrument/

  3. Ideas and perspectives: on the emission of amines from terrestrial vegetation in the context of new atmospheric particle formation

    NASA Astrophysics Data System (ADS)

    Sintermann, J.; Neftel, A.

    2015-06-01

    In this article we summarise recent science which shows how airborne amines, specifically methylamines (MAs), play a key role in new atmospheric particle formation (NPF) by stabilising small molecule clusters. Agricultural emissions are assumed to constitute the most important MA source, but given the short atmospheric residence time of MAs, they can hardly have a direct impact on NPF events observed in remote regions. This leads us to the presentation of existing knowledge focussing on natural vegetation-related MA sources. High MA contents as well as emissions by plants was already described in the 19th century. Strong MA emissions predominantly occur during flowering as part of a pollination strategy. The behaviour is species-specific, but examples of such species are common and widespread. In addition, vegetative plant tissue exhibiting high amounts of MAs might potentially lead to significant emissions. The decomposition of organic material constitutes another, potentially ubiquitous, source of airborne MAs. These mechanisms would provide sources, which could be crucial for the amine's role in NPF, especially in remote regions. Knowledge about vegetation-related amine emissions is, however, very limited, and thus it is also an open question how global change and the intensified cycling of reactive nitrogen over the last 200 years have altered amine emissions from vegetation with a corresponding effect on NPF.

  4. Ideas and Perspectives: On the emission of amines from terrestrial vegetation in the context of atmospheric new particle formation

    NASA Astrophysics Data System (ADS)

    Sintermann, J.; Neftel, A.

    2015-02-01

    In this article we summarise recent science, which shows how airborne amines, specifically methylamines (MAs), play a key role in atmospheric new particle formation (NPF) by stabilising small molecule clusters. Agricultural emissions are assumed to constitute the most important MA source, but given the short atmospheric residence time of MAs, they can hardly have a direct impact on NFP events observed in remote regions. This leads us to the presentation of existing knowledge focussing on natural vegetation-related MA sources. High MA contents as well as emissions by plants have already been described in the 19th century. Strong MA emissions predominantly occur during flowering as part of a pollination strategy. The behaviour is species specific, but examples of such species are common and widespread. In addition, vegetative plant tissue exhibiting high amounts of MAs might potentially lead to significant emissions, and the decomposition of organic material could constitute another source for airborne MAs. These mechanisms would provide sources, which could be crucial for the amine's role in NPF, especially in remote regions. Knowledge about vegetation-related amine emissions is, however, very limited and thus it is also an open question how Global Change and the intensified cycling of reactive nitrogen over the last 200 years have altered amine emissions from vegetation with a corresponding effect on NPF.

  5. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    NASA Astrophysics Data System (ADS)

    Salma, I.; Borsós, T.; Weidinger, T.; Aalto, P.; Hussein, T.; Dal Maso, M.; Kulmala, M.

    2010-06-01

    Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6-1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8×103 to 29×103 cm-3 with a yearly median of 11.8×103 cm-3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79±6)%. Daily average number concentrations in various size fractions and contribution of ultrafine particles to the total particle number showed no seasonal dependency. Monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. Median diameters of the Aitken and accumulation modes were shifted to larger values before nucleation started and over the growth process, which can be related to the presence of aged aerosol under the conditions that favour nucleation and growth. Particle concentrations were usually increased substantially after nucleations. Overall mean and standard deviation of the nucleation mode number concentrations were (10.4±2.8)×103 cm-3. Mean ratio and standard deviation of the nucleation mode number concentration to the total particle number concentration that was averaged for two hours just before the formation was detected was 2.3±1.1. Nucleation unambiguously occurred on 83 days, which represent 27% of all relevant days. Its frequency showed a remarkable seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm-3 s-1 with a mean and standard deviation of (4.2±2.5) cm-3 s-1. Seasonal dependency for the formation rate could not be identified. Growth curves of nucleated particles were usually superimposed on the characteristic diurnal pattern of road traffic direct emissions. The growth rate of the nucleation mode with a median diameter of 6 nm varied from 2.0 to 13.3 nm h-1 with a mean and standard deviation of (7.7±2.4) nm h-1. There was an indicative tendency for larger growth rates in summer and for smaller values in winter. Several indirect evidences suggest that the nucleation events occurred at least over the whole city, and were of regional type.

  6. Femtosecond Laser Ablation Particle Introduction to a Liquid Sampling-Atmospheric Pressure Glow Discharge Ionization Source

    SciTech Connect

    Carado, Anthony J.; Quarles, C. Derrick; Duffin, Andrew M.; Barinaga, Charles J.; Russo, Richard; Marcus, R. Kenneth; Eiden, Gregory C.; Koppenaal, David W.

    2012-01-16

    This work describes the use of a compact, liquid sampling – atmospheric pressure glow discharge (LS-APGD) ionization source to ionize metal particles within a laser ablation aerosol. Mass analysis was performed with a Thermo Scientific Exactive Mass Spectrometer which utilizes an orbitrap mass analyzer capable of producing mass resolution exceeding M/M > 160,000. The LS-APGD source generates a low-power plasma between the surface of an electrolytic solution flowing at several µl min-1 through a fused silica capillary and a counter electrode consisting of a stainless steel capillary employed to deliver the laser ablation particles into the plasma. Sample particles of approximately 100 nm were generated with an Applied Spectra femtosecond laser located remotely and transported through 25 meters of polyurethane tubing by means of argon carrier gas. Samples consisted of an oxygen free copper shard, a disk of solder, and a one-cent U.S. coin. Analyte signal onset was readily detectable relative to the background signal produced by the carrier gas alone. The high mass resolution capability of the orbitrap mass spectrometer was demonstrated on the solder sample with resolution exceeding 90,000 for Pb and 160,000 for Cu. In addition, results from a laser ablation depth-profiling experiment of a one cent coin revealed retention of the relative locations of the ~10 µm copper cladding and zinc rich bulk layers.

  7. Particle-Induced X-Ray Emission Analysis of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Gleason, Colin; Harrington, Charles; Schuff, Katie; Battaglia, Maria; Moore, Robert; Turley, Colin; Vineyard, Michael; Labrake, Scott

    2010-11-01

    We are developing a research program in ion-beam analysis (IBA) of atmospheric aerosols at the Union College Ion-Beam Analysis Laboratory to study the transport, transformation, and effects of airborne pollution in Upstate New York. The simultaneous applications of the IBA techniques of particle-induced X-ray emission (PIXE), Rutherford back-scattering spectrometry (RBS), particle-induced gamma-ray emission (PIGE), and proton elastic scattering analysis (PESA) is a powerful tool for the study of airborne pollution because they are non-destructive and provide quantitative information on nearly all elements of the periodic table. PIXE is the main IBA technique because it is able to detect nearly all elements from Na to U with high sensitivities and low detection limits. The aerosol samples are collected with cascade impactors that allow for the study of particulate matter as a function of particle size and the samples are analyzed using proton beams with energies around 2 MeV from the Union College 1.1-MV Pelletron Accelerator. The emitted X-rays are measured using a silicon drift detector with a resolution of 136 eV. We will describe how the aerosol samples were collected, discuss the PIXE analysis, and present preliminary results.

  8. (Bio)hybrid materials based on optically active particles

    NASA Astrophysics Data System (ADS)

    Reitzig, Manuela; Härtling, Thomas; Opitz, Jörg

    2014-03-01

    In this contribution we provide an overview of current investigations on optically active particles (nanodiamonds, upconversion phospors) for biohybrid and sensing applications. Due to their outstanding properties nanodiamonds gain attention in various application elds such as microelectronics, optical monitoring, medicine, and biotechnology. Beyond the typical diamond properties such as high thermal conductivity and extreme hardness, the carbon surface and its various functional groups enable diverse chemical and biological surface functionalization. At Fraunhofer IKTS-MD we develop a customization of material surfaces via integration of chemically modi ed nanodiamonds at variable surfaces, e.g bone implants and pipelines. For the rst purpose, nanodiamonds are covalently modi ed at their surface with amino or phosphate functionalities that are known to increase adhesion to bone or titanium alloys. The second type of surface is approached via mechanical implementation into coatings. Besides nanodiamonds, we also investigate the properties of upconversion phosphors. In our contribution we show how upconversion phosphors are used to verify sterilization processes via a change of optical properties due to sterilizing electron beam exposure.

  9. Students 'Weigh' Atmospheric Pollution.

    ERIC Educational Resources Information Center

    Caporaloni, Marina

    1998-01-01

    Describes a procedure developed by students that measures the mass concentration of particles in a polluted urban atmosphere. Uses a portable fan and filters of various materials. Compares students' data with official data. (DDR)

  10. Modelling the contribution of biogenic volatile organic compounds to new particle formation in the Jülich plant atmosphere chamber

    NASA Astrophysics Data System (ADS)

    Roldin, P.; Liao, L.; Mogensen, D.; Dal Maso, M.; Rusanen, A.; Kerminen, V.-M.; Mentel, T. F.; Wildt, J.; Kleist, E.; Kiendler-Scharr, A.; Tillmann, R.; Ehn, M.; Kulmala, M.; Boy, M.

    2015-09-01

    We used the Aerosol Dynamics gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM) to simulate the contribution of BVOC plant emissions to the observed new particle formation during photooxidation experiments performed in the Jülich Plant-Atmosphere Chamber and to evaluate how well smog chamber experiments can mimic the atmospheric conditions during new particle formation events. ADCHAM couples the detailed gas-phase chemistry from Master Chemical Mechanism with a novel aerosol dynamics and particle phase chemistry module. Our model simulations reveal that the observed particle growth may have either been controlled by the formation rate of semi- and low-volatility organic compounds in the gas phase or by acid catalysed heterogeneous reactions between semi-volatility organic compounds in the particle surface layer (e.g. peroxyhemiacetal dimer formation). The contribution of extremely low-volatility organic gas-phase compounds to the particle formation and growth was suppressed because of their rapid and irreversible wall losses, which decreased their contribution to the nano-CN formation and growth compared to the atmospheric situation. The best agreement between the modelled and measured total particle number concentration (R2 > 0.95) was achieved if the nano-CN was formed by kinetic nucleation involving both sulphuric acid and organic compounds formed from OH oxidation of BVOCs.

  11. Atmospheric new particle formation and the potential role of organic peroxides

    NASA Astrophysics Data System (ADS)

    Trawny, Katrin; Bonn, Boris; Jacobi, Stefan

    2010-05-01

    New particle formation in the atmosphere belongs to the currently most discussed aspects of atmospheric aerosols with significant implications for cloud formation and microphysics, once these particles have grown beyond about 50 nm in particle diameter. If these particles act as cloud condensation or ice nuclei they can affect the radiation budget at the Earths surface and cause climate couplings important to understand when aiming to predict climate change scenarios. One aspect widely discussed is the potential contribution of organic trace gases from anthropogenic and biogenic sources. In this study we analysed datasets from a Central European measurement station in Germany in a spruce forest approximately 800 m above sea level and a distance of about 20 km to Frankfurt (southeast). Continuous particle size distribution measurements were classified in nucleation-event or not and unidentified and intercompared to meteorological and basic trace gas observations. Additionally meteorological backtrajektories calculated by the German Weather Service for the station every 12 hours have been considered. These led to the following conclusions: Nucleation was most likely if (A) the air has not get significantly into touch with the surface within the last days, or if (B) at least human impact was minor and the air faced forest surfaces mainly (northwest). As observed already in Hyytiälä (Finland) nucleation appeared, when the relative humidity and ambient water vapour mixing ratio were low, ozone was high and the condensation sink was small. A further important point was the amount of global radiation measured at the Taunus Observatory (Mt. Kleiner Feldberg). The higher the radiation, the more likely a nucleation event and the more intense. Temperature impacted on the intensity of nucleation, i.e. the higher the temperature the more intense the event, but did not directly affect the occurrence of an event or not, if a threshold value of ca. -6 °C was exceeded. This latter observation indicates a potential role of biogenic volatile organic compounds (VOCs) as their emission is strongly coupled to temperature. Because of our observations in the laboratory and beacuse of observed nighttime events, we approximated the concentration of different radicals, e.g. OH, HO2 and RO2. The values of RO2 and especially the ones of biogenic (e.g. terpene) origin showed a good correlation with new particle formation occurrence and seemed to be one essential point of several to allow new particle formation to occur. This might be an indication of the important role of the biosphere and its stress effects for the particle formation process. The seasonality observed for the time period since February 2008 displayed two maxima in May and August, September with a minimum in June, when the weather conditions were more humid and is in line with the observations made above. July and August displayed the higest HO2 concentrations, which will act as a sink for the organic peroxy radicals. In connection to the supressive effect of water vapour on terpene induced nucleating molecules (secondary ozonides) this might serve as an explanation for the commonly observed summer minimum in nucleation events.

  12. Polar Northern Hemisphere Middle Atmospheric Influence due to Energetic Particle Precipitation in January 2005

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.

    2010-01-01

    Solar eruptions and geomagnetic activity led to energetic particle precipitation in early 2005, primarily during the January 16-21 period. Production of OH and destruction of ozone have been documented due to the enhanced energetic solar proton flux in January 2005 [e.g., Verronen et al., Geophys. Res. Lett.,33,L24811,doi:10.1029/2006GL028115, 2006; Seppala et al., Geophys. Res. Lett.,33,L07804, doi:10.1029/2005GL025571,2006]. These solar protons as well as precipitating electrons also led to the production of NO(x) (NO, NO2). Our simulations with the Whole Atmosphere Community Climate Model (WACCM) show that NO(x) is enhanced by 20-50 ppbv in the polar Northern Hemisphere middle mesosphere (approx.60-70 km) by January 18. Both the SCISAT-1 Atmospheric Chemistry Experiment (ACE) NO(x) measurements and Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIP AS) nighttime NO2 observations show large increases during this period, in reasonable agreement with WACCM predictions. Such enhancements are considerable for the mesosphere and led to simulated increases in polar Northern Hemisphere upper stratospheric odd nitrogen (NO(y)) of2-5 ppbv into February 2005. The largest ground level enhancement (GLE) of solar cycle 23 occurred on January 20, 2005 with a neutron monitor increase of about 270 percent [Gopalswamy et al., 29th International Cosmic Ray Conference, Pune,00,101-104,2005]. We found that protons of energies 300 to 20,000 MeV, not normally included in our computations, led to enhanced stratospheric NO(y) of less than 1 percent as a result of this GLE. The atmospheric impact of precipitating middle energy electrons (30-2,500 keV) during the January 16-21, 2005 period is also of interest, and an effort is ongoing to include these in WACCM computations. This presentation will show both short- and longer-term changes due to the January 2005 energetic particle precipitation.

  13. Characterization of Spatial Impact of Particles Emitted from a Cement Material Production Facility on Outdoor Particle Deposition in the Surrounding Community

    PubMed Central

    Yu, Chang Ho; Fan, Zhihua (Tina); McCandlish, Elizabeth; Stern, Alan H.; Lioy, Paul J.

    2014-01-01

    The objective of this study was to estimate the contribution of a facility that processes steel production slag into raw material for cement production to local outdoor particle deposition in Camden, NJ. A dry deposition sampler that can house four 37-mm quartz fiber filters was developed and used for the collection of atmospheric particle deposits. Two rounds of particle collection (3–4 weeks each) were conducted in 8–11 locations 200–800 m downwind of the facility. Background samples were concurrently collected in a remote area located ~2 km upwind from the facility. In addition, duplicate surface wipe samples were collected side-by-side from each of the 13 locations within the same sampling area during the first deposition sampling period. One composite source material sample was also collected from a pile stored in the facility. Both the bulk of the source material and the <38 μm fraction subsample were analyzed to obtain the elemental source profile. The particle deposition flux in the study area was higher (24–83 mg/m2 day) than at the background sites (13–17 mg/m2·day). The concentration of Ca, a major element in the cement source production material, was found to exponentially decrease with increasing downwind distance from the facility (P < 0.05). The ratio of Ca/Al, an indicator of Ca enrichment due to anthropogenic sources in a given sample, showed a similar trend. These observations suggest a significant contribution of the facility to the local particle deposition. The contribution of the facility to outdoor deposited particle mass was further estimated by three independent models using the measurements obtained from this study. The estimated contributions to particle deposition in the study area were 1.8–7.4% from the regression analysis of the Ca concentration in particle deposition samples against the distance from the facility, 0–11% from the U.S. Environmental Protection Agency (EPA) Chemical Mass Balance (CMB) source-receptor model, and 7.6–13% from the EPA Industrial Source Complex Short Term (ISCST3) dispersion model using the particle-size-adjusted permit-based emissions estimates. PMID:22070034

  14. Characterization of spatial impact of particles emitted from a cement material production facility on outdoor particle deposition in the surrounding community.

    PubMed

    Yu, Chang Ho; Fan, Zhihua; McCandlish, Elizabeth; Stern, Alan H; Lioy, Paul J

    2011-10-01

    The objective of this study was to estimate the contribution of a facility that processes steel production slag into raw material for cement production to local outdoor particle deposition in Camden, NJ. A dry deposition sampler that can house four 37-mm quartz fiber filters was developed and used for the collection of atmospheric particle deposits. Two rounds of particle collection (3-4 weeks each) were conducted in 8-11 locations 200-800 m downwind of the facility. Background samples were concurrently collected in a remote area located -2 km upwind from the facility. In addition, duplicate surface wipe samples were collected side-by-side from each of the 13 locations within the same sampling area during the first deposition sampling period. One composite source material sample was also collected from a pile stored in the facility. Both the bulk of the source material and the < 38 microm fraction subsample were analyzed to obtain the elemental source profile. The particle deposition flux in the study area was higher (24-83 mg/m2 x day) than at the background sites (13-17 mg/m2day). The concentration of Ca, a major element in the cement source production material, was found to exponentially decrease with increasing downwind distance from the facility (P < 0.05). The ratio of Ca/Al, an indicator of Ca enrichment due to anthropogenic sources in a given sample, showed a similar trend. These observations suggest a significant contribution of the facility to the local particle deposition. The contribution of the facility to outdoor deposited particle mass was further estimated by three independent models using the measurements obtained from this study. The estimated contributions to particle deposition in the study area were 1.8-7.4% from the regression analysis of the Ca concentration in particle deposition samples against the distance from the facility, 0-11% from the U.S. Environmental Protection Agency (EPA) Chemical Mass Balance (CMB) source-receptor model, and 7.6-13% from the EPA Industrial Source Complex Short Term (ISCST3) dispersion model using the particle-size-adjusted permit-based emissions estimates. PMID:22070034

  15. Observational and laboratory studies of optical properties of black and brown carbon particles in the atmosphere using spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Nakayama, Tomoki; Matsumi, Yutaka

    2015-04-01

    Light absorption and scattering by aerosols are as an important contributor to radiation balance in the atmosphere. Black carbon (BC) is considered to be the most potent light absorbing material in the visible region of the spectrum, although light absorbing organic carbon (brown carbon or BrC) and mineral dust may also act as sources of significant absorption, especially in the ultraviolet (UV) and shorter visible wavelength regions. The optical properties of such particles depend on wavelength, particle size and shape, morphology, coating, and complex refractive index (or chemical composition), and therefore accurate in situ measurements of the wavelength dependence of the optical properties of particles are needed. Recently, cavity ring-down spectroscopy (CRDS) and photoacoustic spectroscopy (PAS) have been used for the direct measurements of extinction and absorption coefficients of particles suspended in air. We have applied these techniques to the observational studies of optical properties of BC and BrC in an urban site in Japan and to the laboratory studies of optical properties of secondary organic aerosols (SOAs) generated from a variety of biogenic and anthropogenic volatile organic compounds and those of diesel exhaust particles (DEPs). In the presentation, the basic principles of these techniques and the results obtained in our studies and in the recent literatures will be overviewed. References Guo, X. et al., Measurement of the light absorbing properties of diesel exhaust particles using a three-wavelength photoacoustic spectrometer, Atmos. Environ., 94, 428-437 (2014). Nakayama, T. et al., Measurements of aerosol optical properties in central Tokyo during summertime using cavity ring-down spectroscopy: Comparison with conventional techniques, Atmos. Environ., 44, 3034-3042 (2010). Nakayama, T. et al., Laboratory studies on optical properties of secondary organic aerosols generated during the photooxidation of toluene and the ozonolysis of alpha-pinene, J. Geophys. Res., 115, D24204, doi:10.1029/2010JD014387 (2010). Nakayama, T. et al., Wavelength dependence of refractive index of secondary organic aerosols generated during the ozonolysis and photooxidation of alpha-pinene, SOLA, 8, 119-124 (2012). Nakayama, T. et al., Wavelength and NOx dependent complex refractive index of SOAs generated from the photooxidation of toluene, Atmos. Chem. Phys., 13, 531-545 (2013). Nakayama, T. et al., Properties of light-absorbing aerosols in the Nagoya urban area, Japan, in August 2011 and January 2012: Contributions of brown carbon and lensing effect, J. Geophys. Res. Atmos., 119, 12721-12739 (2014). Nakayama, T. et al., Characterization of a three wavelength photoacoustic soot spectrometer (PASS-3) and a photoacoustic extinctiometer (PAX), J. Meteor. Soc. Japan, (2015, in press).

  16. Chemical characteristics and source apportionment of atmospheric particles during heating period in Harbin, China.

    PubMed

    Huang, Likun; Wang, Guangzhi

    2014-12-01

    Atmospheric particles (total suspended particles (TSPs); particulate matter (PM) with particle size below 10 μm, PM10; particulate matter with particle size below 2.5 μm, PM(2.5)) were collected and analyzed during heating and non-heating periods in Harbin. The sources of PM10 and PM(2.5) were identified by the chemical mass balance (CMB) receptor model. Results indicated that PM(2.5)/TSP was the most prevalent and PM(2.5) was the main component of PM(10), while the presence of PM(10-100) was relatively weak. SO(4)(2-) and NO(3)(-) concentrations were more significant than other ions during the heating period. As compared with the non-heating period, Mn, Ni, Pb, S, Si, Ti, Zn, As, Ba, Cd, Cr, Fe and K were relatively higher during the heating period. In particular, Mn, Ni, S, Si, Ti, Zn and As in PM(2.5) were obviously higher during the heating period. Organic carbon (OC) in the heating period was 2-5 times higher than in the non-heating period. Elemental carbon (EC) did not change much. OC/EC ratios were 8-11 during the heating period, which was much higher than in other Chinese cities (OC/EC: 4-6). Results from the CMB indicated that 11 pollution sources were identified, of which traffic, coal combustion, secondary sulfate, secondary nitrate, and secondary organic carbon made the greatest contribution. Before the heating period, dust and petrochemical industry made a larger contribution. In the heating period, coal combustion and secondary sulfate were higher. After the heating period, dust and petrochemical industry were higher. Some hazardous components in PM(2.5) were higher than in PM(10), because PM(2.5) has a higher ability to absorb toxic substances. Thus PM(2.5) pollution is more significant regarding human health effects in the heating period. PMID:25499495

  17. Investigation of atmospheric particle-bound reactive oxidative species (ROS): Their sources, characterization, and measurement

    NASA Astrophysics Data System (ADS)

    Venkatachari, Prasanna

    The relationships between the observed ROS concentrations in the New York City PMTACS study and various other atmospheric indicator species such as O3, HOx radicals, organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC), as well as the statistical significance of any observable correlations were explored. A statistically significant moderate positive correlation between the O3 and the ROS concentrations, that indicated the local intensity of photochemistry was a moderate factor affecting the formation of particulate ROS in the daytime atmosphere, was observed. The results of the comparison between ROS and HO x concentrations indicated the existence of, at best, a weak positive correlation. The lack of a more positive correlation of the particle-bound ROS, both with ozone as well as other gas phase oxidants, showed the decoupling of the particulate matter ROS from the gas phase oxidants. The comparison of ROS concentrations with OC, EC, and SOC concentrations revealed a statistically significant relationship (P-value < 0.05) only in the case of ROS and SOC. EC and OC, in general exhibited weak, negative correlations with the observed ROS concentrations. The consistency of the positive relationships between ROS and SOC for all the periods suggested that the measured ROS was photochemically driven. The absence of any statistical relevance of primary EC and OC concentrations on the ROS concentrations suggested that primary emissions, especially from motor vehicles, were not a major source of the measured particle-bound ROS. An important objective of this work was to develop a system that could provide a stable throughput of particle-bound ROS, and characterize it in terms of particle size distribution, concentrations, and formed products, such that the results obtained could be viewed in the perspective of atmospheric processes and measurements. A ROS-bearing particle generator was developed, that could deliver known exposures of ROS. It was seen that the system was generally stable with an average ROS generation capability of 5.6 nanomoles of equivalent H2O2/m3 of (aerosol+ozone) flow sampled. Additionally, the alpha-pinene-O3 oxidation chemical system, used in the ROS generator, was studied to elucidate the structures of reaction products using liquid chromatography-multiple stage mass spectrometry (LC/MSn). The classes of compounds identified based on their multiple stage-MS fragmentation patterns, mechanistic considerations of alpha-pinene-O 3 oxidation, and general fragmentation rules, of the products from this reaction system were highly oxygenated species, predominantly containing hydroperoxide and peroxide functional groups. The oxidant species observed were clearly stable for the 1-3 hrs that elapsed during aerosol collection and analysis, and probably for much longer, thus rendering it possible for these species to bind onto particles forming fine particulate organic peroxides that concentrate on the particles and could deliver concentrated doses of ROS in vivo to tissue. The lack of a suitable method to measure ROS on a routine basis has resulted in no work being undertaken to assess the effects of particle-bound ROS on health effects. In order to fill this need, an automated monitor for the sampling of ambient aerosol and the measurement of concentrations of ROS on the sampled aerosol was developed. Potential methods to quantify ROS were compared in order to arrive at a suitable method to automate. The Dichlorofluorescein (DCFH) fluorescence method was found to be the most non-specific, and hence the best suited method for the automated monitor. An integrated sampling-analysis system was designed and constructed based on collection of atmospheric particles in an aqueous slurry, and subsequent detection of the ROS concentration of the slurry using the DCFH fluorescence method. The results of the lab-scale investigation of the ROS sampling-analysis system suggested that the prototype continuous system was capable of detecting particle-bound ROS, and accounting for short-term variabilities in the same. The instrument was found to be capable of detecting nanomolar equivalent concentrations of ROS.

  18. Chemical characteristics and source of size-fractionated atmospheric particle in haze episode in Beijing

    NASA Astrophysics Data System (ADS)

    Tan, Jihua; Duan, Jingchun; Zhen, Naijia; He, Kebin; Hao, Jiming

    2016-01-01

    The abundance, behavior, and source of chemical species in size-fractionated atmospheric particle were studied with a 13-stage low pressure impactor (ELPI) during high polluted winter episode in Beijing. Thirty three elements (Al, Ca, Fe, K, Mg, Na, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, and Pb) and eight water soluble ions (Cl-, NO3-, SO42 -, NH4+, Na+, K+, Ca2 +, and Mg2 +) were determined by ICP/MS and IC, respectively. The size distribution of TC (OC + EC) was reconstructed. Averagely, 51.5 ± 5.3% and 74.1 ± 3.7% of the total aerosol mass was distributed in the sub-micron (PM1) and fine particle (PM2.5), respectively. A significant shift to larger fractions during heavy pollution episode was observed for aerosol mass, NH4+, SO42 -, NO3-, K, Fe, Cu, Zn, Cd, and Pb. The mass size distributions of NH4+, SO42 -, NO3-, and K were dominated by accumulation mode. Size distributions of elements were classified into four main types: (I) elements were enriched within the accumulation mode (< 1 μm, Ge, Se, Ag, Sn, Sb, Cs, Hg, Ti, and Pb); (II) those mass (K, Cr, Mn, Cu, Zn, As, Mo, and Cd) was resided mainly within the accumulation mode, ranged from 1 to 2 μm; (III) Na, V, Co, Ni, and Ga were distributed among fine, intermediate, and coarse modes; and (IV) those which were mainly found within particles larger than 2.7 μm (Al, Mg, Si, Ca, Sc, Tl, Fe, Sr, Zr, and Ba). [H+]cor showed an accumulation mode at 600-700 nm and the role of Ca2 + should be fully considered in the estimation of acidity. The acidity in accumulation mode particles suggested that generally gaseous NH3 was not enough to neutralize sulfate completely. PMF method was applied for source apportionment of elements combined with water soluble ions. Dust, vehicle, aged coal combustion, and sea salt were identified, and the size resolved source apportionments were discussed. Aged coal combustion was the important source of fine particles and dust contributed most to coarse particle.

  19. A comparative study on the varying exposure to atmospheric fine and coarse particles under urban and rural conditions.

    PubMed

    Wolf-Benning, Uta; Schultz, Eckart; Dietze, Volker; Kaminski, Uwe; Endlicher, Wilfried

    2012-11-01

    This paper is based on the results of three air quality studies conducted in Buenos Aires in Berlin, and in German spas between 2003 and 2007. A high comparability of results was ensured by using the same sampling techniques and analytical methods. Total particle sampling was achieved by active sampling of fine (PM2.5) and passive sampling of coarse particles > or = 2.5 microm and giant particles > or = 10 microm. The highly absorbing, black, predominantly carbonaceous particles (BC) of fine particle samples were determined by measuring the total light attenuation of filter samples and interpreting the extinction value as black carbon. The difference between the gravimetric total mass concentration of the PM2.5 samples and the BC is defined as the transparent, mostly mineral fine fraction. In coarse/giant particle samples the mean gray value was determined by means of automated light microscopy with subsequent single-particle analysis. "Opaque" particles were separated from the "transparent" particle fraction by applying a grey value threshold level. Microscopic measurement of individual particles was employed to establish the size distribution of the coarse and giant fraction. Due to different health effects, the separate detection of these components is suggested. Decline functions of particles are given, possibly providing useful information for a more detailed specification of the local particle distribution, and for a better estimate of the individual exposure. Atmospheric dispersal of particles was found effected mainly by source characteristics. An increased, spatially largely constant level of fine transparent particles in Berlin indicates a particle plume originating from photochemical processes. Buenos Aires, in contrast, is characterized by a lower background level of fine transparent particles but is considerably affected by fine black particles from diesel emissions and by a higher resuspension of coarse/giant transparent, mainly soil particles. PMID:23210223

  20. Gas-to-Particle Conversion in Surface Discharge Nonthermal Plasmas and Its Implications for Atmospheric Chemistry

    PubMed Central

    Kim, Hyun-Ha; Ogata, Atsushi

    2011-01-01

    This paper presents some experimental data on gas-to-particle conversion of benzene using nonthermal plasma (NTP) technology and discusses the possibility of its technical application in atmospheric chemistry. Aerosol measurement using a differential mobility analyzer (DMA) revealed that the parts of benzene molecules were converted into a nanometer-sized aerosol. Aerosol formation was found to be highly related with the missing part in carbon balance. Scanning electron microscopy analysis showed that the aerosols formed in synthetic humid air are the collection of nanoparticles. The carbonyl band (C=O) was found to be an important chemical constituent in the aerosol. The potential of the NTP as an accelerated test tool in studying secondary organic aerosol (SOA) formation from VOCs will be also addressed. PMID:22163781

  1. A model for the atmospheric fate of sea salt particles incoastal areas

    NASA Astrophysics Data System (ADS)

    Demoisson, Ambre; Tedeschi, Gilles; Piazzola, Jacques

    2013-04-01

    Aerosol particles affect climate by scattering and absorbing radiation (Charlson et al., 1992), and may affect the heat budget. Among them, the particles generated at the air-sea interface by wave breaking represent a major component of the natural aerosol (Andreae, 1995). Sea-spray aerosols are mechanically produced by the interaction between wind and wave: when the wind speed increases beyond a critical value, waves break to dissipate the excess of energy. This is accompanied by the occurrence of whitecaps (Monahan and O'Muircheartaigh, 1980) and the primary marine aerosol production is directly related to the whitecap fraction. Air entrained into the water breaks up into bubbles, which may be transported to depths of several meters. When the bubbles rise and reach the surface, they burst and produce two kinds of droplets : film drops and jet drops (Blanchard, 1963; Blanchard, 1983; Resch and Afeti, 1991; Resch and Afeti, 1992). Sea-salts dominate atmospheric deposition in maritime regions (Gustafsson and Franzen, 1996; Farrell et al., 1995). However, the fate of marine aerosol particles in the marine atmosphere is still largely unknown. A model for the aerosol transport in coastal areas is then of great interest for a large number of applications among them, climate change and studies on air and water quality. Tedeschi and Piazzola (2011) presented the development of the Marine Aerosol Concentration Model (MACMod), which is a 2D unsteady model dedicated to the atmospheric transport of marine aerosols in the Marine Atmospheric Boundary Layer. However, such a transport model needs to implement an accurate source term for the sea-salt particles. Uncertainties on the sea-salt source function are still large (see Lewis and Schwartz, 2004). In particular, in coastal areas, the sea-spray production through breaking waves depends on both the fetch and the wind speed conditions. In this study, we propose to improve the MACMod model predictions by introducing an accurate sea-salt source function. To this end, the MACMOD model was implemented in the Mediterranean coast using aerosol data measured during an experimental campaign conducted in the French coastal Mediterranean area in 2008 on board the French oceanographic vessel "Atalante." Using the aerosol size distributions measured in different geographical locations south off the French coastal zone, a new source term has been introduced in MACMOD. The Monahan et al. (1986) formulation, depending both on the aerosol radius and the whitecap fraction, has been revisited. First, a separated approach is used for both the film and jet drops, accounting for the different radius modes. Then, a new sea-state dependent model is used for the whitecap fraction. The simulations were then validated with the help of aerosol size distributions recorded on board the ship "Atalante" for different meteorological conditions.

  2. Influences of fireworks on chemical characteristics of atmospheric fine and coarse particles during Taiwan's Lantern Festival

    NASA Astrophysics Data System (ADS)

    Tsai, Hsieh-Hung; Chien, Li-Hsing; Yuan, Chung-Shin; Lin, Yuan-Chung; Jen, Yi-Hsiu; Ie, Iau-Ren

    2012-12-01

    In recent years, the celebration activities of various folk-custom festivals have been getting more and more attention from the citizens in Taiwan. Festivities throughout the whole island are traditionally accompanied by loud and brightly colored firework displays. Among these activities, the firework displays during Taiwan's Lantern Festival in Kaohsiung harbor is one of the largest festivals in Taiwan each year. Therefore, it is of importance to investigate the influence of fireworks displays on the ambient air quality during the Taiwan's Lantern Festival. Field measurements of atmospheric particulate matter (PM) were conducted on February 9th-11th, 2009 during Taiwan's Lantern Festival in Kaohsiung City. Moreover, three kinds of fireworks powders obtained from the same manufacturing factory producing Kaohsiung Lantern Festival fireworks were burned in a self-designed combustion chamber to determine the physicochemical properties of the fireworks' particles and to establish the source profile of firework burning. Several metallic elements of PM during the firework display periods were notably higher than those during the non-firework periods. The concentrations of Mg, K, Pb, and Sr in PM2.5 during the firework periods were 10 times higher than those during the non-firework periods. Additionally, the Cl-/Na+ ratio was approximately 3 during the firework display periods as Cl- came from the chlorine content of the firework powder. Moreover, the OC/EC ratio increased up to 2.8. Results obtained from PCA and CMB receptor modeling showed that major sources of atmospheric particles during the firework display periods in Kaohsiung harbor were fireworks, vehicular exhausts, soil dusts and marine sprays. Particularly, on February 10th, the firework displays contributed approximately 25.2% and 16.6% of PM10 at two downwind sampling sites, respectively.

  3. Measurement of the Hygroscopicity and Wet Removal of Black-Carbon-Containing Particles in the Urban Atmosphere of Tokyo

    NASA Astrophysics Data System (ADS)

    Ohata, Sho; Moteki, Nobuhiro; Mori, Tatsuhiro; Koike, Makoto; Schwarz, Joshua; Takami, Akinori; Kondo, Yutaka

    2015-04-01

    Megacities are very large, concentrated anthropogenic sources of black carbon (BC) aerosols. Freshly emitted BC particles inside megacities affect local air quality and regional and global climate. The microphysical properties (e.g., number size distribution, coating thickness, and hygroscopicity) of atmospheric BC-containing particles are important because their efficiency of wet removal from the atmosphere can be highly dependent on these properties. In this study, we developed a method for independent measurement of the hygroscopicity of BC-free and BC-containing particles, and then applied it to the ambient observation in the urban atmosphere of Tokyo. A single particle soot photometer (SP2) was modified as a humidified-SP2, which quantifies the BC-core mass (BC content within a BC-containing particle) and optical diameter of individual aerosol particles, under controlled relative humidity (RH), by detecting both the laser-induced incandescence emitted and laser light scattered from each particle (Schwarz et al., 2014, Journal of Aerosol Science). Measurements of growth factor (GF) and hygroscopicity parameter κ for BC-free and BC-containing particles can be achieved by combining an aerosol particle mass analyzer with the newly developed humidified-SP2. This method was tested in the laboratory and then employed in ambient observations in summer 2014. The ambient measurements were made while also measuring number size distribution of BC cores in rainwater with a nebulizer-SP2 system. Throughout the observation period, for BC-containing particles with a dry diameter of about 200 nm, the particles with smaller BC fractions tended to represent greater water uptake, and the number fraction of the less hygroscopic (GF < 1.2 at 85% RH) BC-containing particles was more than 70% of the total BC-containing particles. The measured average number size distribution of BC cores in rainwater was larger than that in the surface air before precipitation began, and the dependence of the wet removal of BC-containing particles on their BC-core sizes was successfully explained by the measured microphysical properties of BC-containing particles in the air and an assumed maximum supersaturation that the particles would have experienced during rain events. These measurement data indicated that BC-containing particles in Tokyo, especially particles with small BC cores (or with high critical supersaturation), were efficiently transported upward without being removed by precipitation.

  4. Relative humidity-dependent viscosities of isoprene-derived secondary organic material and atmospheric implications for isoprene-dominant forests

    NASA Astrophysics Data System (ADS)

    Song, M.; Liu, P. F.; Hanna, S. J.; Li, Y. J.; Martin, S. T.; Bertram, A. K.

    2015-05-01

    Oxidation of isoprene is an important source of secondary organic material (SOM) in atmospheric particles, especially in areas such as the Amazon Basin. Information on the viscosities, diffusion rates, and mixing times within isoprene-derived SOM is needed for accurate predictions of air quality, visibility, and climate. Currently, however, this information is not available. Using a bead-mobility technique and a poke-flow technique combined with fluid simulations, the relative humidity (RH)-dependent viscosities of SOM produced from isoprene photo-oxidation were quantified for 20-60 μm particles at 295 ± 1 K. From 84.5 to 0% RH, the viscosities for isoprene-derived SOM varied from ~ 2 × 10-1 to ~ 3 × 105 Pa s, implying that isoprene-derived SOM ranges from a liquid to a semisolid over this RH range. These viscosities correspond to diffusion coefficients of ~ 2 × 10-8 to ~ 2 × 10-14 cm2 s-1 for large organic molecules that follow the Stokes-Einstein relation. Based on the diffusion coefficients, the mixing time of large organic molecules within 200 nm isoprene-derived SOM particles ranges from approximately 0.1 h to less than 1 s. To illustrate the atmospheric implications of this study's results, the Amazon Basin is used as a case study for an isoprene-dominant forest. Considering the RH and temperature range observed in the Amazon Basin and with some assumptions about the dominant chemical compositions of SOM particles in the region, it is likely that SOM particles in this area are liquid and reach equilibrium with large gas-phase organic molecules on short time scales, less than or equal to approximately 0.1 h.

  5. Energetic Particle Precipitation in the Atmosphere: Northern Hemisphere Variability and Transport

    NASA Astrophysics Data System (ADS)

    Holt, Laura A.

    It is well understood that chemical processes in the stratosphere lead to the destruction of ozone (O3). Our interest in these processes is twofold: (1) stratospheric O3 shields the Earth from biologically harmful radiation, and (2) O3 is a radiatively active gas largely responsible for the temperature structure of the middle atmosphere. A subset of chemical processes that is particularly relevant to O3 consists of catalytic cycles. Catalysts destroy O3 without being depleted. The NOx (NO + NO2) catalytic cycle dominates in the middle stratosphere. One source of stratospheric NO x is energetic particle precipitation (EPP), which contributes to the stratospheric odd nitrogen (NOy) budget in the polar winter. Through interaction with O3, NO x created by EPP (EPP-NOx) has the potential to affect not only the composition of the middle atmosphere but, since O3 is a radiatively active gas, temperature and dynamics as well. This leads to the following science questions, which are the questions that motivated my dissertation: (1) How much EPP-NOx is transported to the stratosphere from year to year? (2) What are the important transport processes involved? The research described here focuses on answering the first question through quantification of the amount of EPP-NOx reaching the northern hemisphere stratosphere using satellite data and the second question through state-of-the-art climate simulations designed to elucidate the important transport mechanisms.

  6. Detection of preferential particle orientation in the atmosphere. Development of an alternative polarization lidar system

    DOE PAGESBeta

    Geier, Manfred; Arienti, Marco

    2014-07-19

    Increasing interest in polarimetric characterization of atmospheric aerosols has led to the development of complete sample-measuring (Mueller) polarimeters that are capable of measuring the entire backscattering phase matrix of a probed volume. The Mueller polarimeters consist of several moving parts, which limit measurement rates and complicate data analysis. In this paper, we present the concept of a less complex polarization lidar setup for detection of preferential orientation of atmospheric particulates. On the basis of theoretical considerations of data inversion stability and propagation of measurement uncertainties, an optimum optical configuration is established for two modes of operation (with either a linearmore » or a circular polarized incident laser beam). We discovered that the conceptualized setup falls in the category of incomplete sample-measuring polarimeters and uses four detection channels for simultaneous measurement of the backscattered light. Likewise, the expected performance characteristics are discussed through an example of a typical aerosol with a small fraction of particles oriented in a preferred direction. As a result, the theoretical analysis suggests that achievable accuracies in backscatter cross-sections and depolarization ratios are similar to those with conventional two-channel configurations, while in addition preferential orientation can be detected with the proposed four-channel system for a wide range of conditions.« less

  7. Detection of preferential particle orientation in the atmosphere: Development of an alternative polarization lidar system

    NASA Astrophysics Data System (ADS)

    Geier, Manfred; Arienti, Marco

    2014-12-01

    Increasing interest in polarimetric characterization of atmospheric aerosols has led to the development of complete sample-measuring (Mueller) polarimeters that are capable of measuring the entire backscattering phase matrix of a probed volume. These Mueller polarimeters consist of several moving parts, which limit measurement rates and complicate data analysis. In this paper, we present the concept of a less complex polarization lidar setup for detection of preferential orientation of atmospheric particulates. On the basis of theoretical considerations of data inversion stability and propagation of measurement uncertainties, an optimum optical configuration is established for two modes of operation (with either a linear or a circular polarized incident laser beam). The conceptualized setup falls in the category of incomplete sample-measuring polarimeters and uses four detection channels for simultaneous measurement of the backscattered light. The expected performance characteristics are discussed through an example of a typical aerosol with a small fraction of particles oriented in a preferred direction. The theoretical analysis suggests that achievable accuracies in backscatter cross-sections and depolarization ratios are similar to those with conventional two-channel configurations, while in addition preferential orientation can be detected with the proposed four-channel system for a wide range of conditions.

  8. Detection of preferential particle orientation in the atmosphere. Development of an alternative polarization lidar system

    SciTech Connect

    Geier, Manfred; Arienti, Marco

    2014-07-19

    Increasing interest in polarimetric characterization of atmospheric aerosols has led to the development of complete sample-measuring (Mueller) polarimeters that are capable of measuring the entire backscattering phase matrix of a probed volume. The Mueller polarimeters consist of several moving parts, which limit measurement rates and complicate data analysis. In this paper, we present the concept of a less complex polarization lidar setup for detection of preferential orientation of atmospheric particulates. On the basis of theoretical considerations of data inversion stability and propagation of measurement uncertainties, an optimum optical configuration is established for two modes of operation (with either a linear or a circular polarized incident laser beam). We discovered that the conceptualized setup falls in the category of incomplete sample-measuring polarimeters and uses four detection channels for simultaneous measurement of the backscattered light. Likewise, the expected performance characteristics are discussed through an example of a typical aerosol with a small fraction of particles oriented in a preferred direction. As a result, the theoretical analysis suggests that achievable accuracies in backscatter cross-sections and depolarization ratios are similar to those with conventional two-channel configurations, while in addition preferential orientation can be detected with the proposed four-channel system for a wide range of conditions.

  9. Health risk assessment for residents exposed to atmospheric diesel exhaust particles in southern region of Taiwan

    NASA Astrophysics Data System (ADS)

    Chio, Chia-Pin; Liao, Chung-Min; Tsai, Ying-I.; Cheng, Man-Ting; Chou, Wei-Chun

    2014-03-01

    Evidence shows a strong association among air pollution, oxidative stress (OS), deoxyribonucleic acid (DNA) damage, and diseases. Recent studies indicated that the aging, human neurodegenerative diseases and cancers resulted from mitochondrial dysfunction and OS. The purpose of this study is to provide a probabilistic risk assessment model to quantify the atmospheric diesel exhaust particles (DEP)-induced pre-cancer biomarker response and cancer incidence risk for residents in south Taiwan. We conducted entirely monthly particulate matter sampling data at five sites in Kaohsiung of south Taiwan in the period 2002-2003. Three findings were found: (i) the DEP dose estimates and cancer risk quantification had heterogeneously spatiotemporal difference in south Taiwan, (ii) the pre-cancer DNA damage biomarker and cancer incidence estimates had a positive yet insignificant association, and (iii) all the estimates of cancer incidence in south Taiwan populations fell within and slight lower than the values from previous cancer epidemiological investigations. In this study, we successfully assessed the tumor incidence for residents posed by DEP exposure in south Taiwan compared with the epidemiological approach. Our approach provides a unique way for assessing human health risk for residences exposed to atmospheric DEP depending on specific combinations of local and regional conditions. Our work implicates the importance of incorporating both environmental and health risk impacts into models of air pollution exposure to guide adaptive mitigation strategies.

  10. Liquid chromatography-dopant-assisted atmospheric pressure photoionization-mass spectrometry: Application to the analysis of aldehydes in atmospheric aerosol particles.

    PubMed

    Ruiz-Jiménez, José; Hautala, Sanna; Parshintsev, Jevgeni; Laitinen, Totti; Hartonen, Kari; Petäjä, Tuukka; Kulmala, Markku; Riekkola, Marja-Liisa

    2013-01-01

    A complete methodology based on LC-anisole-toluene dopant-assisted atmospheric pressure photoionization-IT-MS was developed for the determination of aldehydes in atmospheric aerosol particles. For the derivatization, ultrasound was used to accelerate the reaction between the target analytes and 2,4-dinitrophenylhydrazine. The developed methodology was validated for three different samples, gas phase, ultrafine (Dp = 30 ± 4 nm; where Dp stands for particle diameter) and all-sized particles, collected on Teflon filters. The method quantitation limits ranged from 5 to 227 pg. The accuracy and the potential matrix effects were evaluated using standard addition methodology. Recoveries ranged between 91.7 and 109.9%, and the repeatability and the reproducibility of the method developed between 0.5 and 8.0% and between 2.9 and 11.1%, respectively. The results obtained by the developed methodology compared to those provided by the previously validated method revealed no statistical differences. The method developed was applied to the determination of aldehydes in 16 atmospheric aerosol samples (30 nm and all-sized samples) collected at the Station for Measuring Forest Ecosystem-Atmosphere Relations II during spring 2011. The mean concentrations of aldehydes, and oxidation products of terpenes were between 0.05 and 82.70 ng/m(3). PMID:23255385

  11. Effect of atmospheric ageing on volatility and ROS of biodiesel exhaust nano-particles

    NASA Astrophysics Data System (ADS)

    Pourkhesalian, A. M.; Stevanovic, S.; Rahman, M. M.; Faghihi, E. M.; Bottle, S. E.; Masri, A. R.; Brown, R. J.; Ristovski, Z. D.

    2015-03-01

    In the prospect of limited energy resources and climate change, effects of alternative biofuels on primary emissions are being extensively studied. Our two recent studies have shown that biodiesel fuel composition has a~significant impact on primary particulate matter emissions. It was also shown that particulate matter caused by biodiesels was substantially different from the emissions due to petroleum diesel. Emissions appeared to have higher oxidative potential with the increase in oxygen content and decrease of carbon chain length and unsaturation levels of fuel molecules. Overall, both studies concluded that chemical composition of biodiesel is more important than its physical properties in controlling exhaust particle emissions. This suggests that the atmospheric ageing processes, including secondary organic aerosol formation, of emissions from different fuels will be different as well. In this study, measurements were conducted on a modern common-rail diesel engine. To get more information on realistic properties of tested biodiesel particulate matter once they are released into the atmosphere, particulate matter was exposed to atmospheric oxidants, ozone and ultra-violet light; and the change in their properties was monitored for different biodiesel blends. Upon the exposure to oxidative agents, the chemical composition of the exhaust changes. It triggers the cascade of photochemical reactions resulting in the partitioning of semi-volatile compounds between the gas and particulate phase. In most of the cases, aging lead to the increase in volatility and oxidative potential, and the increment of change was mainly dependent on the chemical composition of fuels as the leading cause for the amount and the type of semi-volatile compounds present in the exhaust.

  12. Effect of atmospheric aging on volatility and reactive oxygen species of biodiesel exhaust nano-particles

    NASA Astrophysics Data System (ADS)

    Pourkhesalian, A. M.; Stevanovic, S.; Rahman, M. M.; Faghihi, E. M.; Bottle, S. E.; Masri, A. R.; Brown, R. J.; Ristovski, Z. D.

    2015-08-01

    In the prospect of limited energy resources and climate change, effects of alternative biofuels on primary emissions are being extensively studied. Our two recent studies have shown that biodiesel fuel composition has a significant impact on primary particulate matter emissions. It was also shown that particulate matter caused by biodiesels was substantially different from the emissions due to petroleum diesel. Emissions appeared to have higher oxidative potential with the increase in oxygen content and decrease of carbon chain length and unsaturation levels of fuel molecules. Overall, both studies concluded that chemical composition of biodiesel is more important than its physical properties in controlling exhaust particle emissions. This suggests that the atmospheric aging processes, including secondary organic aerosol formation, of emissions from different fuels will be different as well. In this study, measurements were conducted on a modern common-rail diesel engine. To get more information on realistic properties of tested biodiesel particulate matter once they are released into the atmosphere, particulate matter was exposed to atmospheric oxidants, ozone and ultra-violet light; and the change in their properties was monitored for different biodiesel blends. Upon the exposure to oxidative agents, the chemical composition of the exhaust changes. It triggers the cascade of photochemical reactions resulting in the partitioning of semi-volatile compounds between the gas and particulate phase. In most of the cases, aging lead to the increase in volatility and oxidative potential, and the increment of change was mainly dependent on the chemical composition of fuels as the leading cause for the amount and the type of semi-volatile compounds present in the exhaust.

  13. Solubility of methanol in low-temperature aqueous sulfuric acid and implications for atmospheric particle composition

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    Using traditional Knudsen cell techniques, we find well-behaved Henry's law uptake of methanol in aqueous 45 - 70 wt% H2SO4 solutions at temperatures between 197 and 231 K. Solubility of methanol increases with decreasing temperature and increasing acidity, with an effective Henry's law coefficient ranging from 10(exp 5) - 10(exp 8) M/atm. Equilibrium uptake of methanol into sulfuric acid aerosol particles in the upper troposphere and lower stratosphere will not appreciably alter gas-phase concentrations of methanol. The observed room temperature reaction between methanol and sulfuric acid is too slow to provide a sink for gaseous methanol at the temperatures of the upper troposphere and lower stratosphere. It is also too slow to produce sufficient quantities of soluble reaction products to explain the large amount of unidentified organic material seen in particles of the upper troposphere.

  14. Influence of Ionization Degrees on the Evolutions of Charged Particles in Atmospheric Plasma at Low Altitude

    NASA Astrophysics Data System (ADS)

    Pang, Xuexia; Deng, Zechao; Jia, Pengying; Liang, Weihua; Li, Xia

    2012-08-01

    A zero-dimensional model which includes 56 species of reactants and 427 reactions is used to study the behavior of charged particles in atmospheric plasmas with different ionization degrees at low altitude (near 0 km). The constant coefficient nonlinear equations are solved by using the Quasi-steady-state approximation method. The electron lifetimes are obtained for afterglow plasma with different initial values, and the temporal evolutions of the main charged species are presented, which are dominant in reaction processes. The results show that the electron number density decays quickly. The lifetimes of electrons are shortened by about two orders with increasing ionization degree. Electrons then attach to neutral particles and produce negative ions. When the initial electron densities are in the range of 1010 ~ 1014 cm-3, the negative ions have sufficiently high densities and long lifetimes for air purification, disinfection and sterilization. Electrons, O2-, O4-, CO4- and CO3- are the dominant negative species when the initial electron density ne0 <= 1013 cm-3, and only electrons and CO3- are left when ne0 >= 1015 cm-3 · N+2, N+4 and O+2 are dominant in the positive charges for any ionization degree. Other positive species, such as O+4, N+3, NO+, NO+2, Ar+2 and H3O+·H2O, are dominant only for a certain ionization degree and in a certain period.

  15. Characterisation of atmospheric deposited particles during a dust storm in urban areas of Eastern Australia.

    PubMed

    Gunawardena, Janaka; Ziyath, Abdul M; Bostrom, Thor E; Bekessy, Lambert K; Ayoko, Godwin A; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2013-09-01

    The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant. PMID:23712117

  16. Arsenic speciation in total contents and bioaccessible fractions in atmospheric particles related to human intakes.

    PubMed

    Huang, Minjuan; Chen, Xunwen; Zhao, Yinge; Yu Chan, Chuen; Wang, Wei; Wang, Xuemei; Wong, Ming Hung

    2014-05-01

    Speciation of inorganic trivalent arsenicals (iAs(III)), inorganic pentavalent arsenicals (iAs(V)), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in total arsenic (As) content and its bioaccessible fractions contained in road dust, household air-conditioning (AC) filter dust and PM2.5 was investigated. Inorganic As, especially iAs(V), was observed as the dominant species. Physiologically based extraction test (PBET), an in-vitro gastrointestinal method, was used to estimate the oral As bioaccessibility in coarse particles and the species present in the oral bioaccessible fraction. A composite lung simulating serum was used to mimic the pulmonary condition to extract the respiratory bioaccessible As and its species in PM2.5. Reduction of iAs(V) to iAs(III) occurred in both in-vitro gastrointestinal and lung simulating extraction models. The inorganic As species was the exclusive species for absorption through ingestion and inhalation of atmospheric particles, which was an important exposure route to inorganic As, in addition to drinking water and food consumption. PMID:24534614

  17. Inorganic and Organic Chemical Composition of Atmospheric Particles in the GUÁNICA'S Dry Forest

    NASA Astrophysics Data System (ADS)

    Marrero-Ortiz, W.; Mayol-Bracero, O. L.

    2010-12-01

    The Caribbean region is influenced by natural (e.g., African dust, volcanic ash, sea salt) and anthropogenically (e.g., particles from combustion processes) derived aerosols. Aerosols influence the Earth's radiative budget directly by scattering and absorbing solar radiation in the atmosphere and indirectly by affecting cloud formation. The chemical and physical characterization of aerosols -focusing on African dust and anthropogenic-derived particles- and their study of their seasonal variation are essential to understand their impact on the environment. Guánica’s Dry Forest (GDF) is located in the semi-arid southwestern Puerto Rico, is an excellent example of dry forest life zone and is an UNESCO Man and Biosphere Reserve. Samples were collected during day and nighttime using Stacked-Filter Units. Analyses were performed using thermal/optical analysis for the carbonaceous fraction and ion chromatography for the water-soluble ions. Preliminary results showed that nighttime samples had two times higher concentrations of carbonaceous aerosols (Total Carbon, TC) than the daytime ones. The positive artifact of TC was higher at nighttime (70 %) than daytime (50 %) samples. The predominant ions were Cl-, SO42-, Na+ and NH4+. Daytime samples showed higher concentrations of Cl- and Na+ than nighttime. However, nighttime samples showed decrease in Na+ and Cl- and an increase in NH4+. These results suggest marine origin for daytime samples, and possible anthropogenic influence for nighttime samples.

  18. Occurrence and dry deposition of organophosphate esters in atmospheric particles over the northern South China Sea.

    PubMed

    Lai, Senchao; Xie, Zhiyong; Song, Tianli; Tang, Jianhui; Zhang, Yingyi; Mi, Wenying; Peng, Jinhu; Zhao, Yan; Zou, Shichun; Ebinghaus, Ralf

    2015-05-01

    Nine organophosphate esters (OPEs) in airborne particles were measured during a cruise campaign over the northern South China Sea (SCS) from September to October 2013. The concentration of the total OPEs (∑OPEs) was 47.1-160.9 pg m(-3), which are lower than previous measurements in marine atmosphere environments. Higher OPE concentrations were observed in terrestrially influenced samples, suggesting that OPE concentrations were significantly influenced by air mass transport. Chlorinated OPEs were the dominant OPEs, accounting for 65.8-83.7% of the ∑OPEs. Tris-(2-chloroethyl) phosphate (TCEP) was the predominant OPE compound in the samples (45.0±12.1%), followed by tris-(1-chloro-2-propyl) phosphates (TCPPs) (28.8±8.9%). Dry particle-bound deposition fluxes ranged from 8.2 to 27.8 ng m(-2) d(-1) for the ∑OPEs. Moreover, the dry deposition input of the ∑OPEs was estimated to be 4.98 ton y(-1) in 2013 in a vast area of northern SCS. About half of the input was found to relate to air masses originating from China. PMID:25732631

  19. Behavior of air particles associated with atmospheric recirculation over complex coastal area

    NASA Astrophysics Data System (ADS)

    Lee, Soon-Hwan; Park, Geon-Young; Chang, Lim-Seok; Song, Chang-Keun

    2015-11-01

    Several numerical experiments were carried out over Gwangyang Bay area, which is located southwestern part of the Korean Peninsula, to clarify the characteristics of the recirculation potential and the impact of the spatial size of the model domain on air pollutant dispersion. The numerical models used in this study were Weather and Research Forecasting (WRF) model to assess the atmospheric circulation and FLEXPART to estimate the level of pollutant dispersion. Regardless of the synoptic conditions, the variation in the recirculation potential based on the transported distance of air pollutants agreed well with the change in ozone concentration. Weak synoptic wind and strong regional flow results in the highest recirculation potential in both inland and coastal areas. The concentration in limited areas is strongly associated with the pollutants recirculated by regional circulation. The persistence of synoptic wind often prevents particle recirculation but intensified regional circulation around coastal area is favorable for increasing the returning particles. Therefore, the determined domain size should be large enough to include the trace of recirculated pollutants when weak synoptic wind occurs.

  20. Space Systems - Safety and Compatibility of Materials - Method to Determine the Ignition Susceptibility of Materials or Components to Particle Impact

    NASA Technical Reports Server (NTRS)

    Hirsch, David B.

    2011-01-01

    The scope of this International Technical Specification is to provide a method to determine the ignition susceptibility of materials and components to particle impact. The method can be used to determine the conditions at which ignition and consumption of a specimen material occurs when impacted by single or multiple particles entrained in a flow of gaseous oxygen (GOX). Alternatively, the method can be used to determine if a specific material or component is subject to ignition and sustained combustion in a given flow environment when impacted by single or multiple particles entrained in a flow of GOX.

  1. Investigation of particle sizes in Pluto's atmosphere from the 29 June 2015 occultation

    NASA Astrophysics Data System (ADS)

    Sickafoose, Amanda A.; Bosh, A. S.; Person, M. J.; Zuluaga, C. A.; Levine, S. E.; Pasachoff, J. M.; Babcock, B. A.; Dunham, E. W.; McLean, I.; Wolf, J.; Abe, F.; Bida, T. A.; Bright, L. P.; Brothers, T.; Christie, G.; Collins, P. L.; Durst, R. F.; Gilmore, A. C.; Hamilton, R.; Harris, H. C.; Johnson, C.; Kilmartin, P. M.; Kosiarek, M. R.; Leppik, K.; Logsdon, S.; Lucas, R.; Mathers, S.; Morley, C. J. K.; Natusch, T.; Nelson, P.; Ngan, H.; Pfüller, E.; de, H.-P.; Sallum, S.; Savage, M.; Seeger, C. H.; Siu, H.; Stockdale, C.; Suzuki, D.; Thanathibodee, T.; Tilleman, T.; Tristam, P. J.; Van Cleve, J.; Varughese, C.; Weisenbach, L. W.; Widen, E.; Wiedemann, M.

    2015-11-01

    The 29 June 2015 observations of a stellar occultation by Pluto, from SOFIA and ground-based sites in New Zealand, indicate that haze was present in the lower atmosphere (Bosh et al., this conference). Previously, slope changes in the occultation light curve profile of Pluto’s lower atmosphere have been attributed to haze, a steep thermal gradient, and/or a combination of the two. The most useful diagnostic for differentiating between these effects has been observing occultations over a range of wavelengths: haze scattering and absorption are functions of particle size and are wavelength dependent, whereas effects due to a temperature gradient should be largely independent of observational wavelength. The SOFIA and Mt. John data from this event exhibit obvious central flashes, from multiple telescopes observing over a range of wavelengths at each site (Person et al. and Pasachoff et al., this conference). SOFIA data include Red and Blue observations from the High-speed Imaging Photometer for Occultations (HIPO, at ~ 500 and 850 nm), First Light Infrared Test Camera (FLITECAM, at ~1800 nm), and the Focal Plan Imager (FPI+, at ~ 600 nm). Mt. John data include open filter, g', r', i', and near infrared. Here, we analyze the flux at the bottom of the light curves versus observed wavelength. We find that there is a distinct trend in flux versus wavelength, and we discuss applicable Mie scattering models for different particle size distributions and compositions (as were used to characterize haze in Pluto's lower atmosphere in Gulbis et al. 2015).SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. Support for this work was provided by the National Research Foundation of South Africa, NASA SSO grants NNX15AJ82G (Lowell Observatory), PA NNX10AB27G (MIT), and PA NNX12AJ29G (Williams College), and the NASA SOFIA Cycle 3 grant NAS2-97001 issued by USRA.

  2. An Overview of Energetic Particle Precipitation Effects on the Earth's Atmosphere and (Potentially) Climate

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.

    2012-01-01

    Energetic precipitating particles (EPPs) can cause significant constituent changes in the polar mesosphere and stratosphere (middle atmosphere) during certain periods. Both protons and electrons can influence the polar middle atmosphere through ionization and dissociation processes. EPPs can enhance HOx (H, OH, HO2) through the formation of positive ions followed by complex ion chemistry and NOx (N, NO, NO2) through the dissociation of molecular nitrogen. The solar EPP-created HOx increases can lead to ozone destruction in the mesosphere and upper stratosphere via several catalytic loss cycles. Such middle atmospheric HOx-caused ozone loss is rather short-lived due to the relatively short lifetime (hours) of the HOx constituents. The HOx-caused ozone depletion of greater than 30% has been observed during several large solar proton events (SPEs) in the past 50 years. HOx enhancements due to SPEs were confirmed by observations in solar cycle 23. A number of modeling studies have been undertaken over this time period that show predictions of enhanced HOx accompanied by decreased ozone due to energetic particles. The solar EPP-created NOx family has a longer lifetime than the HOx family and can also lead to catalytic ozone destruction. EPP-caused enhancements of the NOx family can affect ozone promptly, if produced in the stratosphere, or subsequently, if produced in the lower thermosphere or mesosphere and transported to the stratosphere. NOx enhancements due to auroral electrons, medium and high energy electrons, relativistic electron precipitation (REP) events, and SPEs have been measured and/or modeled for decades. Model predictions and measurements show that certain years have significant winter-time meteorological events, which result in the transport of EPP-caused NOx enhancements in the upper mesosphere and lower thermosphere to lower altitudes. The NOx-caused ozone depletion has also been observed during several solar proton events (SPEs) in the past 50 years. Model predictions indicate that the longer-lived SPE-caused polar stratospheric and mesospheric ozone decrease can be >10% for up to five months past the largest events and is statistically significant; however, total ozone measurements do not indicate any long-term SPE impact.

  3. Highly time-resolved chemical characterization of atmospheric fine particles during 2010 Shanghai World Expo

    NASA Astrophysics Data System (ADS)

    Huang, X.-F.; He, L.-Y.; Xue, L.; Sun, T.-L.; Zeng, L.-W.; Gong, Z.-H.; Hu, M.; Zhu, T.

    2012-06-01

    Shanghai, with a population of over 20 million, is the largest mega-city in China. Rapidly increasing industrial and metropolitan emissions have deteriorated its air quality in the past decades, with fine particle pollution as one of the major issues. However, systematic characterization of atmospheric fine particles with advanced measurement techniques has been very scarce in Shanghai. During 2010 Shanghai World Expo, we deployed a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a single particle soot photometer (SP2) in urban Shanghai between 15 May and 10 June 2010 to measure fine particles with a high time resolution. The 4-min resolution PM1 mass concentration ranged from 5.5 to 155 μg m-3, with an average of 29.2 μg m-3. On average, sulfate and organic matter (OM) were the most abundant PM1 components, accounting for 33.3 and 28.7% of the total mass, respectively, while the fraction of nitrate showed an increasing trend with the increasing PM1 loading, indicating the photochemical nature of high fine particle pollution in Shanghai. Taking advantage of HR-ToF-AMS and SP2, OM was found to have an average OM/OC ratio (organic matter mass/organic carbon mass) of 1.55 and black carbon (BC) had an average number fraction of internally mixed BC of 41.2%. Positive matrix factorization (PMF) analysis on the high resolution organic mass spectral dataset identified a hydrocarbon-like (HOA), a semi-volatile oxygenated (SV-OOA), and a low-volatility oxygenated (LV-OOA) organic aerosol component, which on average accounted for 24.0, 46.8, and 29.2% of the total organic mass, respectively. The diurnal patterns of them with interesting time delay possibly implied a photochemical oxidizing process from HOA (and/or its concurrently emitted gaseous organic pollutants) to SV-OOA to LV-OOA. Back trajectory analysis indicated that the northwesterly continental air mass represented the most severe pollutant regional transport condition with the highest nitrate and SV-OOA fractions. In addition, the results in Shanghai were compared with similar measurements performed recently in other mega-cities in the world.

  4. Highly time-resolved chemical characterization of atmospheric fine particles during 2010 Shanghai World Expo

    NASA Astrophysics Data System (ADS)

    Huang, X.-F.; He, L.-Y.; Xue, L.; Sun, T.-L.; Zeng, L.-W.; Gong, Z.-H.; Hu, M.; Zhu, T.

    2012-01-01

    Shanghai, with a population of over 20 million, is the largest mega-city in China. Rapidly increasing industrial and metropolitan emissions have deteriorated its air quality in the past decades, with fine particle pollution as one of the major issues. However, systematic characterization of atmospheric fine particles with advanced measurement techniques has been very scarce in Shanghai. During 2010 Shanghai World Expo, we deployed a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a single particle soot photometer (SP2) in urban Shanghai between 15 May and 10 June 2010 to measure fine particles with a high time resolution. The 4-min resolution PM1 mass concentration ranged from 5.5 to 155 μg m-3, with an average of 29.2 μg m-3. On average, sulfate and organic matter (OM) were the most abundant PM1 components, accounting for 33.3 and 28.7% of the total mass, respectively, while the fraction of nitrate showed an increasing trend with the increasing PM1 loading, indicating the photochemical nature of high fine particle pollution in Shanghai. Taking advantage of HR-ToF-AMS and SP2, OM was found to have an average OM/OC ratio (organic matter mass/organic carbon mass) of 1.55 and black carbon (BC) had an average number fraction of internally mixed BC of 41.2%. Positive matrix factorization (PMF) analysis on the high resolution organic mass spectral dataset identified a hydrocarbon-like (HOA), a semi-volatile oxygenated (SV-OOA), and a low-volatility oxygenated (LV-OOA) organic aerosol component, which on average accounted for 24.0, 46.8, and 29.2% of the total organic mass, respectively. The diurnal patterns of them with interesting time delay possibly implied a photochemical oxidizing process from HOA (and/or its concurrently emitted gaseous organic pollutants) to SV-OOA to LV-OOA. Back trajectory analysis indicated that the northwesterly continental air mass represented the most severe pollutant regional transport condition with the highest nitrate and SV-OOA fractions. In addition, the results in Shanghai were compared with similar measurements performed recently in other mega-cities in the world.

  5. The effect of acid-base clustering and ions on the growth of atmospheric nano-particles.

    PubMed

    Lehtipalo, Katrianne; Rondo, Linda; Kontkanen, Jenni; Schobesberger, Siegfried; Jokinen, Tuija; Sarnela, Nina; Kürten, Andreas; Ehrhart, Sebastian; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Sipilä, Mikko; Yli-Juuti, Taina; Duplissy, Jonathan; Adamov, Alexey; Ahlm, Lars; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Downard, Andrew J; Dunne, Eimear M; Flagan, Richard C; Guida, Roberto; Hakala, Jani; Hansel, Armin; Jud, Werner; Kangasluoma, Juha; Kerminen, Veli-Matti; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Kupiainen-Määttä, Oona; Laaksonen, Ari; Lawler, Michael J; Leiminger, Markus; Mathot, Serge; Olenius, Tinja; Ortega, Ismael K; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud; Rissanen, Matti P; Ruuskanen, Taina; Santos, Filipe D; Schallhart, Simon; Schnitzhofer, Ralf; Simon, Mario; Smith, James N; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Tomé, António; Vaattovaara, Petri; Vehkamäki, Hanna; Vrtala, Aron E; Wagner, Paul E; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Virtanen, Annele; Donahue, Neil M; Carslaw, Kenneth S; Baltensperger, Urs; Riipinen, Ilona; Curtius, Joachim; Worsnop, Douglas R; Kulmala, Markku

    2016-01-01

    The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a coherent framework and discuss their significance in the atmosphere. PMID:27197574

  6. Mobility particle size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions

    NASA Astrophysics Data System (ADS)

    Wiedensohler, A.; Birmili, W.; Nowak, A.; Sonntag, A.; Weinhold, K.; Merkel, M.; Wehner, B.; Tuch, T.; Pfeifer, S.; Fiebig, M.; Fjäraa, A. M.; Asmi, E.; Sellegri, K.; Depuy, R.; Venzac, H.; Villani, P.; Laj, P.; Aalto, P.; Ogren, J. A.; Swietlicki, E.; Williams, P.; Roldin, P.; Quincey, P.; Hüglin, C.; Fierz-Schmidhauser, R.; Gysel, M.; Weingartner, E.; Riccobono, F.; Santos, S.; Grüning, C.; Faloon, K.; Beddows, D.; Harrison, R.; Monahan, C.; Jennings, S. G.; O'Dowd, C. D.; Marinoni, A.; Horn, H.-G.; Keck, L.; Jiang, J.; Scheckman, J.; McMurry, P. H.; Deng, Z.; Zhao, C. S.; Moerman, M.; Henzing, B.; de Leeuw, G.; Löschau, G.; Bastian, S.

    2012-03-01

    Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer. We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data. Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research) and ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30%, which could not be explained. The network reference mobility spectrometers with identical design agreed within ±4% in the peak particle number concentration when all settings were done carefully. The consistency of these reference instruments to the total particle number concentration was demonstrated to be less than 5%. Additionally, a new data structure for particle number size distributions was introduced to store and disseminate the data at EMEP (European Monitoring and Evaluation Program). This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between different networks and sites, and their transparency and traceability back to raw data.

  7. ESCAPING PARTICLE FLUXES IN THE ATMOSPHERES OF CLOSE-IN EXOPLANETS. I. MODEL OF HYDROGEN

    SciTech Connect

    Guo, J. H.

    2011-06-01

    A multi-fluid model for an atomic hydrogen-proton mixture in the upper atmosphere of an extrasolar planet is presented when the continuity and momentum equations of each component have already been solved with an energy equation. The particle-number density, temperature distribution, and structure of velocity can be found by using the model. I chose two special objects, HD 209458b and HD 189733b, for discussion and concluded that their predicted mass-loss rates are consistent with those observed. The most important physical process in coupling each component is the charge exchange, which couples atomic hydrogen tightly with protons. Most of the hydrogen escapes from hot Jupiters as protons, especially in the young star-planet system. I found that the single-fluid model can describe the escape of particles when the mass-loss rate is higher than a few times 10{sup 9} g s{sup -1}, while below 10{sup 9} g s{sup -1} the multi-fluid model is more suitable because of the decoupling of particles. Assuming an energy limit, I found that the predicted mass-loss rates of HD 189733b are a factor of 10 larger than those calculated by my models because of a high degree of ionization. For ionized wind, which is mainly composed of protons, assuming an energy limit is no longer effective. I fitted the mass-loss rates of the ionized wind as a function of F{sub UV} by calculating the variation of the mass-loss rates with UV fluxes.

  8. Autofluorescence of atmospheric bioaerosols - fluorescent biomolecules, biological standard particles and potential interferences

    NASA Astrophysics Data System (ADS)

    Pöhlker, C.; Huffmann, J. A.; Pöschl, U.

    2012-04-01

    Primary biological aerosol particles (PBAP) such as pollen, fungal spores, bacteria, biogenic polymers and debris from larger organisms are known to influence atmospheric chemistry and physics, the biosphere and public health. PBAP account for up to ~30% of fine and up to ~70% of coarse particulate matter in urban, rural and pristine environment and are released with estimated emission rates of up to ~1000 Tg/a [1]. Continuous measurements of the abundance, variability and diversity of PBAP have been difficult until recently, however. The application of on-line instruments able to detect autofluorescence from biological particles in real-time has been a promising development for the measurement of PBAP concentrations and fluxes in different environments [2,3]. The detected fluorescent biological aerosol particles (FBAP) can be regarded as a subset of PBAP, although the exact relationship between PBAP and FBAP is still being investigated. Autofluorescence of FBAP is usually a superposition of fluorescence from a mixture of individual fluorescent molecules (fluorophores). Numerous biogenic fluorophores such as amino acids (e.g., tryptophan, tyrosine), coenzymes (e.g., NAD(P)H, riboflavin) and biopolymers (e.g., cellulose) emit fluorescent light due to heterocyclic aromatic rings or conjugated double bonds within their molecular structures. The tryptophan emission peak is a common feature of most bioparticles because the amino acid is a constituent of many proteins and peptides. The influence of the coenzymes NAD(P)H and riboflavin on the autofluorescence of bacteria can be regarded as an indicator for bacterial metabolism and has been utilized to discriminate between viable and non-viable organisms [4]. However, very little information is available about other essential biofluorophores in fungal spores and pollen. In order to better understand the autofluorescence behavior of FBAP, we have used fluorescence spectroscopy and fluorescence microscopy to analyze standard bioparticles (pollen, fungal spores, and bacteria) as well as atmospherically relevant chemical substances. We found varying levels of fluorescent emission and significant differences in the spectral properties of major PBAP classes. The combination will support the quantitative interpretation of data obtained by real-time FBAP instrumentation [5]. [1] Elbert, W., Taylor, P. E., Andreae, M. O., & Pöschl, U. (2007). Atmos. Chem. Phys., 7, 4569-4588. [2] Huffman, J. A., Treutlein, B., & Pöschl, U. (2010). Atmos. Chem. Phys., 10, 3215-3233. [3] Pöschl, U., et al. (2010). Science, 329, 1513-1516. [4] Lakowicz, J., Principles of fluorescence spectroscopy, Plenum publishers, New York, 1999. [5] Pöhlker, C., Huffman, J. A., & Pöschl, U., (2012). Atmos. Meas. Tech., 5, 37-71.

  9. Space charge distribution measurement methods and particle loaded insulating materials

    NASA Astrophysics Data System (ADS)

    Holé, S.; Sylvestre, A.; Gallot Lavallée, O.; Guillermin, C.; Rain, P.; Rowe, S.

    2006-03-01

    In this paper the authors discuss the effects of particles (fillers) mixed in a composite polymer on the space charge measurement techniques. The origin of particle-induced spurious signals is determined and silica filled epoxy resin is analysed using the laser-induced-pressure-pulse (LIPP) method, the pulsed-electro-acoustic (PEA) method and the laser-induced-thermal-pulse (LITP) method. A spurious signal identified as the consequence of a piezoelectric effect of some silica particles is visible for all the method. Moreover, space charges are clearly detected at the epoxy/silica interface after a 10 kV mm-1 poling at room temperature for 2 h.

  10. ATMOSPHERIC DRY PARTICLE DEPOSITION OF POPS AND TRACE METALS IN AN URBAN- AND INDUSTRIALLY-IMPACTED MID-ATLANTIC ESTUARY (AEOLOS B MID-ATLANTIC)

    EPA Science Inventory

    Emissions of hazardous air pollutants into the coastal urban-industrial atmosphere increase atmospheric depositional fluxes to proximate water bodies. Dry deposition of large particles containing persistent organic pollutants (POPs) and trace metals were a major contribu...

  11. Characteristics of atmospheric particulate mercury in size-fractionated particles during haze days in Shanghai

    NASA Astrophysics Data System (ADS)

    Chen, Xiaojia; Balasubramanian, Rajasekhar; Zhu, Qiongyu; Behera, Sailesh N.; Bo, Dandan; Huang, Xian; Xie, Haiyun; Cheng, Jinping

    2016-04-01

    Atmospheric particulate mercury (PHg) is recognized as a global pollutant that requires regulation because of its significant impacts on both human health and wildlife. The haze episodes that occur frequently in China could influence the transport and fate of PHg. To examine the characteristics of PHg during haze and non-haze days, size-fractioned particles were collected using thirteen-stage Nano-MOUDI samplers (10 nm-18 μm) during a severe haze episode (from December 2013 to January 2014) in Shanghai. The PHg concentration on haze days (4.11 ± 0.53 ng m-3) was three times higher than on non-haze days (1.34 ± 0.15 ng m-3). The ratio of the PHg concentration to total gaseous mercury (TGM) ranged from 0.42 during haze days to 0.21 during non-haze days, which was possibly due to the elevated concentration of particles for gaseous elemental mercury (GEM) adsorption, elevated sulfate and nitrate contributing to GEM oxidation, and the catalytic effect of elevated water-soluble inorganic metal ions. PHg/PM10 during haze days (0.019 ± 0.004 ng/μg) was lower than during non-haze days (0.024 ± 0.002 ng/μg), and PHg/PM10 was significantly reduced with an increasing concentration of PM10, which implied a relatively lower growth velocity of mercury than other compositions on particles during haze days, especially in the diameter range of 0.018-0.032 μm. During haze days, each size-fractioned PHg concentration was higher than the corresponding fraction on non-haze days, and the dominant particle size was in the accumulation mode, with constant accumulation to a particle size of 0.56-1.0 μm. The mass size distribution of PHg was bimodal with peaks at 0.32-0.56 μm and 3.1-6.2 μm on non-haze days, and 0.56-1.0 μm and 3.1-6.2 μm on haze days. There was a clear trend that the dominant size for PHg in the fine modes shifted from 0.32-0.56 μm during non-haze days to 0.56-1.0 μm on haze days, which revealed the higher growth velocity of PHg on haze days due to the condensation and accumulation of Hg in particles. Traffic emissions and coal combustion may contribute to the high concentrations of Hg, because PHg of every size was found to correlate positively with SO2, NO2, and CO. A correlation was found between every mode of PHg and relative humidity, which affected the gas-particle partitioning of semi-volatile organic compounds, resulting in effective partitioning into aerosols. The strong correlations between Hg and water-soluble ions implied the oxidation of elemental Hg was the main gas-to-particle chemical transformation process.

  12. Pesticides in the atmosphere: a comparison of gas-particle partitioning and particle size distribution of legacy and current-use pesticides

    NASA Astrophysics Data System (ADS)

    Degrendele, C.; Okonski, K.; Melymuk, L.; Landlová, L.; Kukučka, P.; Audy, O.; Kohoutek, J.; Čupr, P.; Klánová, J.

    2015-09-01

    This study presents a comparison of seasonal variation, gas-particle partitioning and particle-phase size distribution of organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in air. Two years (2012/2013) of weekly air samples were collected at a background site in the Czech Republic using a high-volume air sampler. To study the particle-phase size distribution, air samples were also collected at an urban and rural site in the area of Brno, Czech Republic, using a cascade impactor separating atmospheric particulates according to six size fractions. The timing and frequencies of detection of CUPs related to their legal status, usage amounts and their environmental persistence, while OCPs were consistently detected throughout the year. Two different seasonal trends were noted: certain compounds had higher concentrations only during the growing season (April-September) and other compounds showed two peaks, first in the growing season and second in plowing season (October-November). In general, gas-particle partitioning of pesticides was governed by physicochemical properties, with higher vapor pressure leading to higher gas phase fractions, and associated seasonality in gas-particle partitioning was observed in nine pesticides. However, some anomalous partitioning was observed for fenpropimorph and chlorpyrifos suggesting the influence of current pesticide application on gas-particle distributions. Nine pesticides had highest particle phase concentrations on fine particles (< 0.95 μm) and four pesticides on coarser (> 1.5 μm) particles.

  13. Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime

    NASA Astrophysics Data System (ADS)

    Wu, Z. J.; Zheng, J.; Shang, D. J.; Du, Z. F.; Wu, Y. S.; Zeng, L. M.; Wiedensohler, A.; Hu, M.

    2016-02-01

    Simultaneous measurements of particle number size distribution, particle hygroscopic properties, and size-resolved chemical composition were made during the summer of 2014 in Beijing, China. During the measurement period, the mean hygroscopicity parameters (κs) of 50, 100, 150, 200, and 250 nm particles were respectively 0.16 ± 0.07, 0.19 ± 0.06, 0.22 ± 0.06, 0.26 ± 0.07, and 0.28 ± 0.10, showing an increasing trend with increasing particle size. Such size dependency of particle hygroscopicity was similar to that of the inorganic mass fraction in PM1. The hydrophilic mode (hygroscopic growth factor, HGF > 1.2) was more prominent in growth factor probability density distributions and its dominance of hydrophilic mode became more pronounced with increasing particle size. When PM2.5 mass concentration was greater than 50 μg m-3, the fractions of the hydrophilic mode for 150, 250, and 350 nm particles increased towards 1 as PM2.5 mass concentration increased. This indicates that aged particles dominated during severe pollution periods in the atmosphere of Beijing. Particle hygroscopic growth can be well predicted using high-time-resolution size-resolved chemical composition derived from aerosol mass spectrometer (AMS) measurements using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule. The organic hygroscopicity parameter (κorg) showed a positive correlation with the oxygen to carbon ratio. During the new particle formation event associated with strongly active photochemistry, the hygroscopic growth factor or κ of newly formed particles is greater than for particles with the same sizes not during new particle formation (NPF) periods. A quick transformation from external mixture to internal mixture for pre-existing particles (for example, 250 nm particles) was observed. Such transformations may modify the state of the mixture of pre-existing particles and thus modify properties such as the light absorption coefficient and cloud condensation nuclei activation.

  14. Real time analysis of lead-containing atmospheric particles in Beijing during springtime by single particle aerosol mass spectrometry.

    PubMed

    Ma, Li; Li, Mei; Huang, Zhengxu; Li, Lei; Gao, Wei; Nian, Huiqing; Zou, Lilin; Fu, Zhong; Gao, Jian; Chai, Fahe; Zhou, Zhen

    2016-07-01

    Using a single particle aerosol mass spectrometer (SPAMS), the chemical composition and size distributions of lead (Pb)-containing particles with diameter from 0.1 μm to 2.0 μm in Beijing were analyzed in the spring of 2011 during clear, hazy, and dusty days. Based on mass spectral features of particles, cluster analysis was applied to Pb-containing particles, and six major classes were acquired consisting of K-rich, carboneous, Fe-rich, dust, Pb-rich, and Cl-rich particles. Pb-containing particles accounted for 4.2-5.3%, 21.8-22.7%, and 3.2% of total particle number during clear, hazy and dusty days, respectively. K-rich particles are a major contribution to Pb-containing particles, varying from 30.8% to 82.1% of total number of Pb-containing particles, lowest during dusty days and highest during hazy days. The results reflect that the chemical composition and amount of Pb-containing particles has been affected by meteorological conditions as well as the emissions of natural and anthropogenic sources. K-rich particles and carbonaceous particles could be mainly assigned to the emissions of coal combustion. Other classes of Pb-containing particles may be associated with metallurgical processes, coal combustion, dust, and waste incineration etc. In addition, Pb-containing particles during dusty days were first time studied by SPAMS. This method could provide a powerful tool for monitoring and controlling of Pb pollution in real time. PMID:27085059

  15. Particle alignment and clustering in sheared granular materials composed of platy particles.

    PubMed

    Boton, Mauricio; Estrada, Nicolas; Azéma, Emilien; Radjaï, Farhang

    2014-11-01

    By means of molecular dynamics simulations, we investigate the texture and local ordering in sheared packings composed of cohesionless platy particles. The morphology of large packings of platy particles in quasistatic equilibrium is complex due to the combined effects of local nematic ordering of the particles and anisotropic orientations of contacts between particles. We find that particle alignment is strongly enhanced by the degree of platyness and leads to the formation of face-connected clusters of exponentially decaying size. Interestingly, due to dynamics in continuous shearing, this ordering phenomenon emerges even in systems composed of particles of very low platyness differing only slightly from spherical shape. The number of clusters is an increasing function of platyness. However, at high platyness the proportion of face-face interactions is too low to allow for their percolation throughout the system. PMID:25412821

  16. SiC particle cracking in powder metallurgy processed aluminum matrix composite materials

    SciTech Connect

    Wang, B.; Janowski, G.M.; Patterson, B.R.

    1995-09-01

    Particle cracking is one of the key elements in the fracture process of particulate-reinforced metal-matrix composite (MMC) materials. The present study quantitatively examined the amount of new surface are created by particle cracking and the number fraction of cracked particles in a series of SiC-reinforced aluminum-matrix composite materials. These composite materials were fabricated by liquid-phase sintering and contained 9 vol pct of 23, 63, or 142 {micro}m SiC. The matrix properties were varied by heat treating to either an underaged or peak-aged condition. In general, the new surface area created by particle cracking (S{sub V}) and the number fraction of cracked particles (F{sub no}) were linearly dependent on the local strain along the tensile specimen. Multiple cracks were frequently observed in the composites containing large particles. It was found that the new surface area created by particle cracking per unit strain was higher for the case of high-strength matrices and was not systematically affected by particle size within the range studied. The number fraction of cracked particles was affected by both particle size and matrix strength. A higher number fraction of particles cracked in the composites reinforced with large particles and with high matrix yield strengths. These results are interpreted in terms of the size of the particle defects, which is a function of particle size, and the critical flaw size necessary to crack a given particle, which is a function of the stress on the particle. The new surface area created by cracking and the fraction of cracked particles were related and are in good agreement for the large and medium sized particles.

  17. Characterisation of trace metals in atmospheric particles in the vicinity of iron and steelmaking industries in Australia

    NASA Astrophysics Data System (ADS)

    Mohiuddin, K.; Strezov, V.; Nelson, P. F.; Stelcer, E.

    2014-02-01

    The aims of this work are to provide a detailed physicochemical assessment of atmospheric particles collected in the vicinity of three iron and steelmaking plants and to indicate the importance of chemical characterisation of the particles, in addition to the assessment of the particle size and concentrations. In this study, atmospheric sampling sites were selected downstream of three iron and steel processing operations in Australia and one background site in an urban area with little industrial activity. The collected particles were analysed for a range of particle size mass concentrations and detailed chemical analysis of the trace metals Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn in the corresponding particle size ranges was carried out. The PM2.5 fractions in the PM10 particles at all sampling sites ranged from 35 to 62% indicating fine particles made a significant contribution to this size fraction at these sampling sites. Similarly, PM1 to the total PM10 at all sites varied from 20 to 46% and contributed significantly to the PM10 mass loading. When compared to the background sampling site, all detected metals in the particles collected near the iron and steelmaking operations had 3.4-14 times higher concentrations of PM10, PM2.5 and PM1. Iron (Fe) was found to be the dominant metal in the particles collected in vicinity of the iron and steel processing industries contributing up to 12% of the total particle mass loading. This study suggests that the metal composition of PM10, PM2.5 and PM1 varies significantly between sites and the associated metal exposure value is considerably higher in the vicinity of iron and steel processing industries than in the urban area for the same particle concentration level.

  18. Ignition Resistance of Polymeric Materials to Particle Impact in High-Pressure Oxygen

    NASA Technical Reports Server (NTRS)

    Forsyth, Elliot T.; Stolzfus, Joel M.; Fries, Joseph (Technical Monitor)

    2000-01-01

    Particle impact ignition has been the primary cause of numerous fires in oxygen systems. This ignition phenomenon is known to occur where particles are present in high-velocity gas, and where impact occurs on a flammable material. The particle impact ignition behavior of many metals has been widely studied, but the particle impact ignition behavior of polymeric materials is relatively unknown. Particle impact ignition in polymeric materials is a concern as these materials are commonly used in component seat and seal applications, where high-velocity particle impacts can occur. This study evaluates several polymeric materials and compares the minimum temperature required for ignition (threshold temperature) of these materials: Kel-F 81 (CTFE), Teflon (PTFE), PEEK, Vespel SP-21, and Nylon 6/6. The materials were configured as targets in the White Sands Test Facility high-velocity particle impact test system. Gaseous oxygen was flowed at 4000 psi and sonic velocity, and the targets were impacted with 2000-micron aluminum 2017 particles. This paper discusses the results of these tests and ranks the materials according to their threshold temperatures at these conditions.

  19. Coupled electrostatic and material surface stresses yield anomalous particle interactions and deformation

    NASA Astrophysics Data System (ADS)

    Kemp, B. A.; Nikolayev, I.; Sheppard, C. J.

    2016-04-01

    Like-charges repel, and opposite charges attract. This fundamental tenet is a result of Coulomb's law. However, the electrostatic interactions between dielectric particles remain topical due to observations of like-charged particle attraction and the self-assembly of colloidal systems. Here, we show, using both an approximate description and an exact solution of Maxwell's equations, that nonlinear charged particle forces result even for linear material systems and can be responsible for anomalous electrostatic interactions such as like-charged particle attraction and oppositely charged particle repulsion. Furthermore, these electrostatic interactions and the deformation of such particles have fundamental implications for our understanding of macroscopic electrodynamics.

  20. Chemical Imaging and Stable Isotope Analysis of Atmospheric Particles by NanoSIMS (Invited)

    NASA Astrophysics Data System (ADS)

    Sinha, B.; Harris, E. J.; Pöhlker, C.; Wiedemann, K. T.; van Pinxteren, D.; Tilgner, A.; Fomba, K. W.; Schneider, J.; Roth, A.; Gnauk, T.; Fahlbusch, B.; Mertes, S.; Lee, T.; Collett, J. L.; Shiraiwa, M.; Gunthe, S. S.; Smith, M.; Artaxo, P. P.; Gilles, M.; Kilcoyne, A. L.; Moffet, R.; Weigand, M.; Martin, S. T.; Poeschl, U.; Andreae, M. O.; Hoppe, P.; Herrmann, H.; Borrmann, S.

    2013-12-01

    Chemical imaging analysis of the internal distribution of chemical compounds by a combination of SEM-EDX, and NanoSIMS allows investigating the physico-chemical properties and isotopic composition of individual aerosol particles. Stable sulphur isotope analysis provides insight into the sources, sinks and oxidation pathways of SO2 in the environment. Oxidation by OH radicals, O3 and H2O2 enriches the heavier isotope in the product sulphate, whereas oxidation by transition metal ions (TMI), hypohalites and hypohalous acids depletes the heavier isotope in the product sulphate. The isotope fractionation during SO2 oxidation by stabilized Criegee Intermediate radicals is unknown. We studied the relationship between aerosol chemical composition and predominant sulphate formation pathways in continental clouds in Central Europe and during the wet season in the Amazon rain forest. Sulphate formation in continental clouds in Central Europe was studied during HCCT-2010, a lagrangian-type field experiment, during which an orographic cloud was used as a natural flow-through reactor to study in-cloud aerosol processing (Harris et al. 2013). Sulphur isotopic compositions in SO2 and H2SO4 gas and particulate sulphate were measured and changes in the sulphur isotope composition of SO2 between the upwind and downwind measurement sites were used to determine the dominant SO2 chemical removal process occurring in the cloud. Changes in the isotopic composition of particulate sulphate revealed that transition metal catalysis pathway was the dominant SO2 oxidation pathway. This reaction occurred primarily on coarse mineral dust particles. Thus, sulphate produced due to in-cloud SO2 oxidation is removed relatively quickly from the atmosphere and has a minor climatic effect. The aerosol samples from the Amazonian rainforest, a pristine tropical environment, were collected during the rainy season. The samples were found to be dominated by SOA particles in the fine mode and primary biological aerosol particles in the coarse mode (Pöhlker et al. 2012). We applied STXM-NEXAFS analysis, SEM-EDX analysis and NanoSIMS analysis to investigate the morphology, chemical composition and isotopic composition of aerosol samples. Biogenic salt particles emitted from active biota in the rainforest were found to be enriched in the heavier sulphur isotope, whereas particles with a high organic mass fraction modified by condensation of VOC oxidation products and/or cloud processing were significantly depleted in the heavier sulphur isotope compared to the seed particles. This indicates either a depleted gas phase source of sulphur dioxide contributed to the sulphate formation via the H2O2, O3 or OH oxidation pathway or an unaccounted reaction pathway which depletes the heavier isotope in the product sulphate contributes to the secondary sulphate formation in the pristine Amazon rainforest. Harris, E., et al., Science 340, 727-730, 2013 Pöhlker, C., Science 337, 1075-1078, 2012

  1. ISSARS Aerosol Database : an Incorporation of Atmospheric Particles into a Universal Tool to Simulate Remote Sensing Instruments

    NASA Technical Reports Server (NTRS)

    Goetz, Michael B.

    2011-01-01

    The Instrument Simulator Suite for Atmospheric Remote Sensing (ISSARS) entered its third and final year of development with an overall goal of providing a unified tool to simulate active and passive space borne atmospheric remote sensing instruments. These simulations focus on the atmosphere ranging from UV to microwaves. ISSARS handles all assumptions and uses various models on scattering and microphysics to fill the gaps left unspecified by the atmospheric models to create each instrument's measurements. This will help benefit mission design and reduce mission cost, create efficient implementation of multi-instrument/platform Observing System Simulation Experiments (OSSE), and improve existing models as well as new advanced models in development. In this effort, various aerosol particles are incorporated into the system, and a simulation of input wavelength and spectral refractive indices related to each spherical test particle(s) generate its scattering properties and phase functions. These atmospheric particles being integrated into the system comprise the ones observed by the Multi-angle Imaging SpectroRadiometer(MISR) and by the Multiangle SpectroPolarimetric Imager(MSPI). In addition, a complex scattering database generated by Prof. Ping Yang (Texas A&M) is also incorporated into this aerosol database. Future development with a radiative transfer code will generate a series of results that can be validated with results obtained by the MISR and MSPI instruments; nevertheless, test cases are simulated to determine the validity of various plugin libraries used to determine or gather the scattering properties of particles studied by MISR and MSPI, or within the Single-scattering properties of tri-axial ellipsoidal mineral dust particles database created by Prof. Ping Yang.

  2. Source reconciliation of atmospheric gas-phase and particle-phase pollutants during a severe photochemical smog episode.

    PubMed

    Schauer, James J; Fraser, Matthew P; Cass, Glen R; Simoneit, Bernd R T

    2002-09-01

    A comprehensive organic compound-based receptor model is developed that can simultaneously apportion the source contributions to atmospheric gas-phase organic compounds, semivolatile organic compounds, fine particle organic compounds, and fine particle mass. The model is applied to ambient data collected at four sites in the south coast region of California during a severe summertime photochemical smog episode, where the model determines the direct primary contributions to atmospheric pollutants from 11 distinct air pollution source types. The 11 sources included in the model are gasoline-powered motor vehicle exhaust, diesel engine exhaust, whole gasoline vapors, gasoline headspace vapors, organic solvent vapors, whole diesel fuel, paved road dust, tire wear debris, meat cooking exhaust, natural gas leakage, and vegetative detritus. Gasoline engine exhaust plus whole gasoline vapors are the predominant sources of volatile organic gases, while gasoline and diesel engine exhaust plus diesel fuel vapors dominate the emissions of semivolatile organic compounds from these sources during the episode studied at all four air monitoring sites. The atmospheric fine particle organic compound mass was composed of noticeable contributions from gasoline-powered motor vehicle exhaust, diesel engine exhaust, meat cooking, and paved road dust with smaller but quantifiable contributions from vegetative detritus and tire wear debris. In addition, secondary organic aerosol, which is formed from the low-vapor pressure products of gas-phase chemical reactions, is found to be a major source of fine particle organic compound mass under the severe photochemical smog conditions studied here. The concentrations of secondary organic aerosol calculated in the present study are compared with previous fine particle source apportionment results for less intense photochemical smog conditions. It is shown that estimated secondary organic aerosol concentrations correlate fairly well with the concentrations of 1,2-benzenedicarboxylic acid in the atmospheric fine particle mass, indicating that aromatic diacids may be useful in the quantification of certain sources of secondary organic aerosol in the atmosphere. PMID:12322754

  3. Aerosol Measurements in the Atmospheric Surface Layer at L'Aquila, Italy: Focus on Biogenic Primary Particles

    NASA Astrophysics Data System (ADS)

    Pitari, Giovanni; Coppari, Eleonora; De Luca, Natalia; Di Carlo, Piero; Pace, Loretta

    2014-09-01

    Two year measurements of aerosol concentration and size distribution (0.25 μm < d < 30 μm) in the atmospheric surface layer, collected in L'Aquila (Italy) with an optical particle counter, are reported and analysed for the different modes of the particle size distribution. A different seasonal behaviour is shown for fine mode aerosols (largely produced by anthropogenic combustion), coarse mode and large-sized aerosols, whose abundance is regulated not only by anthropogenic local production, but also by remote natural sources (via large scale atmospheric transport) and by local sources of primary biogenic aerosols. The observed total abundance of large particles with diameter larger than 10 μm is compared with a statistical counting of primary biogenic particles, made with an independent technique. Results of these two observational approaches are analysed and compared to each other, with the help of a box model driven by observed meteorological parameters and validated with measurements of fine and coarse mode aerosols and of an atmospheric primary pollutant of anthropogenic origin (NOx). Except in winter months, primary biogenic particles in the L'Aquila measurement site are shown to dominate the atmospheric boundary layer population of large aerosol particles with diameter larger than 10 μm (about 80 % of the total during summer months), with a pronounced seasonal cycle, contrary to fine mode aerosols of anthropogenic origin. In order to explain these findings, the main mechanisms controlling the abundance and variability of particulate matter tracers in the atmospheric surface layer are analysed with the numerical box-model.

  4. Biogenic particles in the surface microlayer and overlaying atmosphere in the central Arctic Ocean during summer

    NASA Astrophysics Data System (ADS)

    Leck, Caroline; Bigg, E. Keith

    2005-09-01

    Transmission electron microscopy photographs of airborne particles are compared with those of particles found in the surface microlayer of the open water between ice floes in the central Arctic Ocean in summer. The similarity in morphology, physical properties, X-ray spectra and a chemical reaction of the numerous aggregates and their building blocks predominantly smaller than 70 nm diameter, and of bacteria and other micro-organisms found in both, strongly suggests that the airborne particles were ejected from the water by bursting bubbles. The shape of the size distribution of aggregates in the air is very similar to that in the water, each with a well-defined Aitken mode but shifted towards smaller sizes. Diffuse electron-transparent material joining and surrounding the heat resistant and non-hygroscopic particulates in both the air and water is shown to have properties consistent with the exopolymer secretions (EPS) of microalgae and bacteria in the water. EPS are highly surface-active, highly hydrated molecules that can spontaneously assemble into gels. They are broken down by ultraviolet light or acidification. These properties provide an explanation for the different resistance to dehydration of bacteria from air and water samples when subjected to a vacuum, and the apparent absence of sea salt on airborne bacteria and aggregates. The difference in size distribution between the air and water samples is also explained. The role of EPS and particulate matter from the open lead surface microlayer in the production of the airborne Aitken mode particles and cloud condensation nuclei is examined and concluded to be very important.

  5. Autofluorescence of atmospheric bioaerosols - Biological standard particles and the influence of environmental conditions

    NASA Astrophysics Data System (ADS)

    Pöhlker, Christopher; Huffman, J. Alex; Förster, Jan-David; Pöschl, Ulrich

    2013-04-01

    Primary biological aerosol particles (PBAP) such as pollen, fungal spores, bacteria, biogenic polymers and debris from larger organisms are known to influence atmospheric chemistry and physics, the biosphere and public health. PBAP can account for up to ~30% of fine and up to ~70% of coarse particulate matter in urban, rural and pristine environment and are released with estimated emission rates of up to ~1000 Tg/a [1]. Continuous measurements of the abundance, variability and diversity of PBAP have been difficult until recently, however. The application of on-line instruments able to detect autofluorescence from biological particles in real-time has been a promising development for the measurement of PBAP concentrations and fluxes in different environments [2,3]. The detected fluorescent biological aerosol particles (FBAP) can be regarded as a subset of PBAP, although the exact relationship between PBAP and FBAP is still being investigated. Autofluorescence of FBAP is usually a superposition of fluorescence from a mixture of individual fluorescent molecules (fluorophores). Numerous biogenic fluorophores such as amino acids (e.g., tryptophan, tyrosine), coenzymes (e.g., NAD(P)H, riboflavin) and biopolymers (e.g., cellulose) emit fluorescent light due to heterocyclic aromatic rings or conjugated double bonds within their molecular structures. The tryptophan emission peak is a common feature of most bioparticles because the amino acid is a constituent of many proteins and peptides. The influence of the coenzymes NAD(P)H and riboflavin on the autofluorescence of bacteria can be regarded as an indicator for bacterial metabolism and has been utilized to discriminate between viable and non-viable organisms [4]. However, very little information is available about other essential biofluorophores in fungal spores and pollen. In order to better understand the autofluorescence behavior of FBAP, we have used fluorescence spectroscopy and fluorescence microscopy to analyze standard bioparticles (pollen, fungal spores, and bacteria) as well as atmospherically relevant chemical substances. We addressed the sensitivity and selectivity of autofluorescence based online techniques. Moreover, we investigated the influence of environmental conditions, such as relative humidity and oxidizing agents in the atmosphere, on the autofluorescence signature of standard bioparticles. Our results will support the molecular understanding and quantitative interpretation of data obtained by real-time FBAP instrumentation [5,6]. [1] Elbert, W., Taylor, P. E., Andreae, M. O., & Pöschl, U. (2007). Atmos. Chem. Phys., 7, 4569-4588. [2] Huffman, J. A., Treutlein, B., & Pöschl, U. (2010). Atmos. Chem. Phys., 10, 3215-3233. [3] Pöschl, U., et al. (2010). Science, 329, 1513-1516. [4] Lakowicz, J., Principles of fluorescence spectroscopy, Plenum publishers, New York, 1999. [5] Pöhlker, C., Huffman, J. A., & Pöschl, U., (2012). Atmos. Meas. Tech., 5, 37-71. [6] Pöhlker, C., Huffman, J. A., Förster J.-D., & Pöschl, U., (2012) in preparation.

  6. Microgel particles for the delivery of bioactive materials

    DOEpatents

    Frechet, Jean M. J.; Murthy Niren

    2010-03-23

    Novel microgels, microparticles and related polymeric materials capable of delivering bioactive materials to cells for use as vaccines or therapeutic agents. The materials are made using a crosslinker molecule that contains a linkage cleavable under mild acidic conditions. The crosslinker molecule is exemplified by a bisacryloyl acetal crosslinker. The new materials have the common characteristic of being able to degrade by acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell. The materials can also be used for the delivery of therapeutics to the acidic regions of tumors and sites of inflammation.

  7. Microgel particles for the delivery of bioactive materials

    DOEpatents

    Frechet, Jean M.; Murthy, Niren

    2006-06-06

    Novel microgels, microparticles and related polymeric materials capable of delivering bioactive materials to cells for use as vaccines or therapeutic agents. The materials are made using a crosslinker molecule that contains a linkage cleavable under mild acidic conditions. The crosslinker molecule is exemplified by a bisacryloyl acetal crosslinker. The new materials have the common characteristic of being able to degrade by acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell. The materials can also be used for the delivery of therapeutics to the acidic regions of tumors and sites of inflammation.

  8. Estimation of particle size variations for laser speckle rheology of materials

    PubMed Central

    Hajjarian, Zeinab; Nadkarni, Seemantini K.

    2015-01-01

    Laser speckle rheology (LSR) is an optical technique for assessing the viscoelastic properties of materials with several industrial, biological, and medical applications. In LSR, the viscoelastic modulus, G* (?), of a material is quantified by analyzing the temporal fluctuations of speckle patterns. However, the size of scattering particles within the material also influences the rate of speckle fluctuations, independent of sample mechanical properties, and complicates the accurate estimation of G* (?). Here, we demonstrate that the average particle size may be retrieved from the azimuth-angle dependence of time-averaged speckle intensities, permitting the accurate quantification of the viscoelastic moduli of materials with unknown particle size distribution using LSR. PMID:25723427

  9. Atmospheric Effects of Energetic Particle Precipitation in the Arctic Winter 1978-1979 Revisited

    NASA Technical Reports Server (NTRS)

    Holt, L. A.; Randall, C. E.; Harvey, V. L.; Remsberg, E. E.; Stiller, G. P.; Funke, B.; Bernath, P. F.; Walker, K. A.

    2012-01-01

    The Limb Infrared Monitor of the Stratosphere (LIMS) measured polar stratospheric enhancements of NO2 mixing ratios due to energetic particle precipitation (EPP) in the Arctic winter of 1978-1979. Recently reprocessed LIMS data are compared to more recent measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) to place the LIMS measurements in the context of current observations. The amount of NOx (NO + NO2) entering the stratosphere that has been created by EPP in the mesosphere and lower thermosphere (EPP-NOx) has been quantified for the 1978-1979 and 2002-2003 through 2008-2009 Arctic winters. The NO2 enhancements in the LIMS data are similar to those in MIPAS and ACE-FTS data in the Arctic winters of 2002-2003, 2004-2005, 2006-2007, and 2007-2008. The largest enhancement by far is in 2003-2004 (approximately 2.2 Gmol at 1500 K), which is attributed to a combination of elevated EPP and unusual dynamics that led to strong descent in the upper stratosphere/lower mesosphere in late winter. The enhancements in 2005-2006 and 2008-2009, during which large stratospheric NOx enhancements were caused by a dynamical situation similar to that in 2003 2004, are larger than in all the other years (except 2003-2004) at 3000 K. However, by 2000 K the enhancements in 2005-2006 (2008-2009) are on the same order of magnitude as (smaller than) all other years. These results highlight the importance of the timing of the descent in determining the potential of EPP-NOx for reaching the middle stratosphere.

  10. Preliminary studies on the source of PM 10 aerosol particles in the atmosphere of Shanghai City by analyzing single aerosol particles

    NASA Astrophysics Data System (ADS)

    Li, X.; Zhu, J.; Guo, P.; Wang, J.; Qiu, Z.; Lu, R.; Qiu, H.; Li, M.; Jiang, D.; Li, Y.; Zhang, G.

    2003-09-01

    To identify the origin of PM 10 (particulate matter with aerodynamic diameter equal to or less than 10 μm) in the atmosphere of Shanghai City, single PM 10 particles from two environmental monitor locations and six pollution emitter sources were measured by scanning nuclear microprobe techniques. Every PM 10 particle is characterized by its micro-PIXE spectrum. The strategy of micro-PIXE spectra combined with the pattern recognition technique is applied to identify original sources of measured PM 10 particles. The results of this investigation show that the most of the measured PM 10 particles are derived from building construction sites, cement factories, vehicle exhaust, coal boilers and steel mills.

  11. Insitu measurements of laser-induced-fluorescence spectra of single atmospheric organic carbon aerosol particles for their partial classification. (Invited)

    NASA Astrophysics Data System (ADS)

    Pinnick, R. G.; Pan, Y.; Hill, S.; Rosen, J. M.; Chang, R. K.

    2009-12-01

    Aerosols are ubiquitous in the earth’s atmosphere. Within the last two decades, the importance of organic carbon aerosols (OCAs) has been widely recognized. OCAs have both natural and anthropogenic sources and have effects ranging from atmospheric radiative forcing to human health. Improved methods for measuring and classifying OCAs are needed for better understanding their sources, transformation, and fate. In this talk we focus on the use of a relatively new technique for characterization of single OCA particles in atmospheric aerosol: ultraviolet laser-induced-fluorescence (UV-LIF). UV-LIF spectra of atmospheric aerosols measured at multiple sites with different regional climate (Adelphi, MD, New Haven, CT, and Las Cruces, NM) are reported. A hierarchical clustering method was used to cluster (approximately 90%) of the single-particle UV-LIF spectra into 8-10 groups (clusters). Some of these clusters have spectra that are similar to spectra of some important classes of atmospheric aerosol, such as humic/fulvic acids and humic-like substances, bacteria, cellulose, marine aerosol, and polycyclic aromatic hydrocarbons. The most highly populated clusters, and some of the less populated ones, appear at all sites. On average, spectra characteristic of humic/fulvic acids and humic-like-substances (HULIS) comprise 28-43% of fluorescent particles at all three sites; whereas cellulose-like spectra contribute only 1-3%.

  12. VIABLE BACTERIAL AEROSOL PARTICLE SIZE DISTRIBUTIONS IN THE MIDSUMMER ATMOSPHERE AT AN ISOLATED LOCATION IN THE HIGH DESERT CHAPARRAL

    EPA Science Inventory

    The viable bacterial particle size distribution in the atmosphere at the Hanford Nuclear Reservation, Richland, WA during two 1-week periods in June 1992, was observed at three intervals during the day (morning, midday and evening) and at three heights (2, 4, and 8 m) above groun...

  13. Influence of particle size and material properties on mucociliary clearance from the airways.

    PubMed

    Henning, Andreas; Schneider, Marc; Nafee, Noha; Muijs, Leon; Rytting, Erik; Wang, Xiaoying; Kissel, Thomas; Grafahrend, Dirk; Klee, Doris; Lehr, Claus-Michael

    2010-08-01

    Mucociliary clearance (MC), designed by evolution to eliminate inhaled and possibly noxious material from the airways, considerably limits the benefit of inhalation therapy. Although the principles of MC seem to be understood, there are still many open questions on mucociliary particle clearance. In this study a trachea-based in vitro model was used to investigate the effect of particle size, zeta-potential, and mucoadhesive particle properties on mucociliary particle clearance. As different sized particles (50-6000 nm) were tested at equal mass concentrations, size related factors, namely particle number and particle surface area, varied by several orders of magnitude between the experiments. Surprisingly, particle clearance for 50 nm up to 6000 nm-sized polystyrene particles did not differ significantly (p < 0.05): 50 nm (2.9 +/- 0.6 mm/min); 100 nm (3.8 +/- 0.9 mm/min); 1000 nm (3.8 +/- 0.8 mm/min); 6000 nm (3.2 +/- 0.6 mm/min). In clear contrast, particles prepared from different PLGA-based copolymers (polylactic-co-glycolic acid) showed a significant effect on particle transport. PEG-PLGA particles (polyethylene glycol) showed the fastest and normal transport rates (5.9 +/- 1.7 mm/min) compared to the ICRP's (International Commission of Radiological Protection) standard value for average tracheal transport rates (5.5 mm/min). Mucoadhesive chitosan-PLGA particles were transported at the slowest rate (0.7 +/- 0.3 mm/min) of all particles tested. Overall, particle size and zeta-potential seem to be relatively uncritical, whereas material properties and the related particle surface chemistry significantly influence mucociliary particle clearance. Considering these findings in future drug formulation seems to be a promising strategy to improve inhalation therapy by prolonged particle/drug residence time within the airways. PMID:20500091

  14. A model of the atmospheric metal deposition by cosmic dust particles

    NASA Astrophysics Data System (ADS)

    McNeil, W. J.

    1993-11-01

    We have developed a model of the deposition of meteoric metals in Earth's atmosphere. The model takes as input the total mass influx of material to the Earth and calculates the deposition rate at all altitudes through solution of the drag and subliminal equations in a Monte Carlo-type computation. The diffusion equation is then solved to give steady state concentration of complexes of specific metal species and kinetics are added to calculate the concentration of individual complexes. Concentrating on sodium, we calculate the Na(D) nightglow predicted by the model, and by introduction of seasonal variations in lower tropospheric ozone based on experimental results, we are able to duplicate the seasonal variation of mid-latitude nightglow data.

  15. On the Response Time of Single Levitated Particles of Atmospherically Relevant Composition to Changes in Relative Humidity at Low Temperatures

    NASA Astrophysics Data System (ADS)

    Lienhard, Daniel; Krieger, Ulrich

    2013-04-01

    Recent studies have shown that atmospheric aerosol particles can adopt an amorphous solid state, particularly under cold and dry conditions. The diffusion of water molecules in these particles is believed to be slow enough such that the particles are not able to equilibrate immediately to changes in the relative humidity. This retarded response has consequences for both the heterogeneous chemistry on these particles and their ability to act as cloud condensation nuclei. In this work, we present the experimentally observed signatures of particles which showed kinetically impeded water uptake and release. Single levitated particles, 2 to 20 microns in radius, are levitated without wall contact in an electrodynamic balance and analyzed with optical techniques. Further, we demonstrate that these signatures can be used to compute the liquid-phase water diffusion coefficient in the concentration range where the liquid-phase diffusion limits the equilibration to the gas phase, i.e. in the highly concentrated range for most aqueous systems. As heterogeneous crystallization is suppressed, the procedure described here is sensible to a concentration and temperature range where traditional methods to measure diffusion coefficients might produce unsatisfying results. The model substances investigated in this study can be regarded as surrogates for atmospheric aerosol. The derived diffusion coefficients together with literature data on pure water are parameterized as a function of concentration and temperature and can be used to directly calculate the response time of aerosol particles to changes in the ambient conditions.

  16. Atmospheric-Pressure Plasma Interaction with Soft Materials as Fundamental Processes in Plasma Medicine.

    PubMed

    Takenaka, Kosuke; Miyazaki, Atsushi; Uchida, Giichiro; Setsuhara, Yuichi

    2015-03-01

    Molecular-structure variation of organic materials irradiated with atmospheric pressure He plasma jet have been investigated. Optical emission spectrum in the atmospheric-pressure He plasma jet has been measured. The spectrum shows considerable emissions of He lines, and the emission of O and N radicals attributed to air. Variation in molecular structure of Polyethylene terephthalate (PET) film surface irradiated with the atmospheric-pressure He plasma jet has been observed via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). These results via XPS and FT-IR indicate that the PET surface irradiated with the atmospheric-pressure He plasma jet was oxidized by chemical and/or physical effect due to irradiation of active species. PMID:26413628

  17. Particle number size distribution in the eastern Mediterranean: Formation and growth rates of ultrafine airborne atmospheric particles

    NASA Astrophysics Data System (ADS)

    Kopanakis, I.; Chatoutsidou, S. E.; Torseth, K.; Glytsos, T.; Lazaridis, M.

    2013-10-01

    Particle number concentration was measured between June 2009 and June 2010 at Akrotiri research station in a rural/suburban region of western Crete (Greece). Overall, the available data covered 157 days during the aforementioned period of measurements. The objectives were to study the number size distribution characteristics of ambient aerosols and furthermore to identify new particle formation events and to evaluate particle formation rates and growth rates of the newborn particles. Aerosol particles with mobility diameters between 10 and 1100 nm were measured using a Scanning Mobility Particle Sizer (SMPS) system. Measurements were performed at ambient relative humidities. The median total particle number concentration was 525 #/cm3 whereas the number concentration ranged between 130 #/cm3 and 9597 #/cm3. The average percentage of particles with diameters between 10 nm and 100 nm (N10-100) to total particles was 53% during summer and spring, but reached 80% during winter. Maximum average contribution of nano-particles (10 nm < Dp < 50 nm) to total particles was recorded also in winter and was attributed partly to the effect of local heating. Furthermore, back trajectories (HYSPLIT model) showed that different air mass origins are linked to different levels of particle number concentrations, with higher values associated with air masses passing from polluted areas before reaching the Akrotiri station. Modal analysis of the measured size distribution data revealed a strong nucleation mode during winter (15-25 nm), which can be correlated with emissions from local sources (domestic heating). The nucleation mode was observed also during the spring campaigns and was partly linked to new particle formation events. On the contrary, an accumulation mode (80-120 nm) prevailed in the measurements during summer campaigns, when the station area was influenced by polluted air masses arriving mainly from Eastern Europe. In total, 13 new particle formation events were recorded during the 157 days of measurements. Nucleation events were associated with low values of N100 particle number concentration and reduced coagulation sinks. Mean growth and formation rates were calculated and showed values equal to 6 nm hr-1 and 13 cm-3 s-1, respectively.

  18. The origins of liner material in a shaped charge jet particle

    SciTech Connect

    Zernow, L.; Chapyak, E.J.; Meyer, K.A.; Zernow, R.H.

    1992-02-01

    An improved high resolution LaGrangean tracer particle technique (using 198 identified tracer particles arranged as 99 particle pairs) has been used with an Eulerian Code (MESA 2D) to determine the locations in the jet to which liner material flows from various tagged locations in the liner, during the collapse, jet formation and jet stretching process. Time dependent strain and strain rate data has been computed, using the identified particle pairs of LaGrangean tracer particles as linear strain gauges. Sharp radial gradients of strain and strain rate have been found in the jet, with the liner material flowing nearest the jet axis being subjected to the highest strains and strain rates. Liner material from many extended initial locations along the liner can be traced by this method to jet locations corresponding to individual jet particles. The new quantitative data derived is illustrated with selected examples whose interpretation is discussed.

  19. The origins of liner material in a shaped charge jet particle

    SciTech Connect

    Zernow, L. ); Chapyak, E.J.; Meyer, K.A. ); Zernow, R.H. )

    1992-01-01

    An improved high resolution LaGrangean tracer particle technique (using 198 identified tracer particles arranged as 99 particle pairs) has been used with an Eulerian Code (MESA 2D) to determine the locations in the jet to which liner material flows from various tagged locations in the liner, during the collapse, jet formation and jet stretching process. Time dependent strain and strain rate data has been computed, using the identified particle pairs of LaGrangean tracer particles as linear strain gauges. Sharp radial gradients of strain and strain rate have been found in the jet, with the liner material flowing nearest the jet axis being subjected to the highest strains and strain rates. Liner material from many extended initial locations along the liner can be traced by this method to jet locations corresponding to individual jet particles. The new quantitative data derived is illustrated with selected examples whose interpretation is discussed.

  20. Kinetic study of heterogeneous ozonolysis of alachlor, trifluralin and terbuthylazine adsorbed on silica particles under atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Pflieger, Maryline; Monod, Anne; Wortham, Henri

    To better understand the atmospheric behaviour of pesticides, heterogeneous ozonolysis of three herbicides (alachlor, terbuthylazine and trifluralin) adsorbed on silica particles were performed in a flow reactor. The experimental setup used in this study and previously validated ( Pflieger et al., 2009) has been specially developed to investigate extremely slow reactivity. The pesticides were adsorbed on particles using a gas/solid adsorption equilibrium, in order to simulate atmospheric conditions. After exposure to ozone concentrations ranging from 5 to 41 ppm during 90 min to 6 h, the kinetics were calculated by comparing the initial and the remaining amounts of pesticides adsorbed on silica particles. This work offers the first results of heterogeneous ozonolysis of alachlor and trifluralin adsorbed on mineral particles. Although alachlor and terbuthylazine were expected to react with ozone, no degradation was observed which leads to a lifetime higher than 8 months towards ozonolysis (for 40 ppb of O 3). A significant degradation of trifluralin adsorbed on silica particles by heterogeneous ozonolysis was observed. The experimental data could be fit by both the Langmuir-Rideal and the Langmuir-Hinshelwood models resulting in atmospheric lifetimes (towards heterogeneous ozonolysis) of 40 and 32 days respectively (for 40 ppb of O 3). These results are discussed and compared to other studies.

  1. Development of a computer model for calculation of radioactive materials into the atmosphere after an accident

    SciTech Connect

    Schershakov, V.

    1997-11-01

    Secondary atmospheric contamination with radioactive dust and chemical species deposited on the ground and resuspended by wind occur very widely. This process is particularly pronounced in case of extensive contamination of soil and under extreme weather conditions, for example, during dust storms. The mechanism of wind dust generation consists in the following. At low wind speed U=2-3 m/s, which is most common in midlatitude, small radioactive dust particles (diameter of hundredth of a micron to 10-20 microns) are lifted from soil surface due to turbulent vortexes. Under the gravitational force the particles of 1-2 micron diameter practically do not settle. Larger dust particles cannot remain in the air for a long time: they are lifted by turbulent vortexes and settle, their motion in the wind flow is jump-wise and the interaction of particles with the flow is called saltation /I/. Saltation is the main mechanism of dust generation up to the wind velocity at which wind erosion starts. The size of dust particles can be as large as 100 pm. When dropping they can be ricocheting from ground or pass the impulse to other particles which begin rolling over and jumping up. The process of dust transport by wind can be compared to a chain reaction. At the velocity of 10 m/s large particles of about 500 pm stop skipping and roll over only, while particles of more than 1 mm remain stationary. Thus, the fine fraction is blown out from the polydispersed soil particles. The intensity of wind resuspension of radioactive dust from the ground is characterized either by a resuspension factor or a resuspension rate.

  2. Processing materials inside an atmospheric-pressure radiofrequency nonthermal plasma discharge

    DOEpatents

    Selwyn, Gary S.; Henins, Ivars; Park, Jaeyoung; Herrmann, Hans W.

    2006-04-11

    Apparatus for the processing of materials involving placing a material either placed between an radio-frequency electrode and a ground electrode, or which is itself one of the electrodes. This is done in atmospheric pressure conditions. The apparatus effectively etches or cleans substrates, such as silicon wafers, or provides cleaning of spools and drums, and uses a gas containing an inert gas and a chemically reactive gas.

  3. The Ultrafine Mineralogy of a Molten Interplanetary Dust Particle as an Example of the Quench Regime of Atmospheric Entry Heating

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1996-01-01

    Melting and degassing of interplanetary dust particle L2005B22 at approx. 1200 C was due to flash heating during atmospheric entry. Preservation of the porous particle texture supports rapid quenching from the peak heating temperature whereby olivine and pyroxene nanocrystals (3 nm-26 nm) show partial devitrification of the quenched melt at T approx. = 450 C - 740 C. The implied ultrahigh cooling rates are calculated at approx. 105 C/h-106 C/h, which is consistent with quench rates inferred from the temperature-time profiles based on atmospheric entry heating models. A vesicular rim on a nonstoichiometric relic forsterite grain in this particle represents either evaporative magnesium loss during flash heating or thermally annealed ion implantation texture.

  4. Modeling of the optical properties of nonspherical particles in the atmosphere

    NASA Astrophysics Data System (ADS)

    Chen, Guang

    The single scattering properties of atmospheric particles are fundamental to radiative simulations and remote sensing applications. In this study, an efficient technique, namely, the pseudo-spectral time-domain (PSTD) method which was first developed to study acoustic wave propagation, is applied to the scattering of light by nonspherical particles with small and moderate size. Five different methods are used to discretize Maxwell's equations in the time domain. The perfectly matched layer (PML) absorbing boundary condition is employed in the present simulation for eliminating spurious wave propagations caused by the spectral method. A 3-D PSTD code has been developed on the basis of the five aforementioned discretization methods. These methods provide essentially the same solutions in both absorptive and nonabsorptive cases. In this study, the applicability of the PSTD method is investigated in comparison with the Mie theory and the T-matrix method. The effects of size parameter and refractive index on simulation accuracy are discussed. It is shown that the PSTD method is quite accurate when it is applied to the scattering of light by spherical and nonspherical particles, if the spatial resolution is properly selected. Accurate solutions can also be obtained from the PSTD method for size parameter of 80 or refractive index of 2.0+j0. Six ice crystal habits are defined for the PSTD computational code. The PSTD results are compared with the results acquired from the finite difference time domain (FDTD) method at size parameter 20. The PSTD method is about 8-10 times more efficient than the conventional FDTD method with similar accuracy. In this study, the PSTD is also applied to the computation of the phase functions of ice crystals with a size parameter of 50. Furthermore, the PSTD, the FDTD, and T-matrix methods are applied to the study of the optical properties of horizontally oriented ice crystals. Three numerical schemes for averaging horizontal orientations are developed in this study. The feasibility of using equivalent circular cylinders as surrogates of hexagonal prisms is discussed. The horizontally oriented hexagonal plates and the equivalent circular cylinders have similar optical properties when the size parameter is in the region about from 10 to 40. Otherwise, the results of the two geometries are substantially different.

  5. Source apportionment of fine atmospheric particles in Marseille: a one year study

    NASA Astrophysics Data System (ADS)

    Marchand, Nicolas; Salameh, Dalia; Detournay, Anais; Wortham, Henri; Jaffrezo, Jean-Luc; Piot, Christine; Armengaud, Alexandre; Piga, Damien; Parra, Michael; Deveze, Magali

    2013-04-01

    Marseille is the second most populated city in France with more than one million inhabitants. With traffic of about 88 million tons (Mt) in 2011, Marseille is also the most important port of the Mediterranean Sea, and also in the vicinity of the large petrochemical and industrial area of Fos-Berre, located 40 km northwest of the metropolitan area. For these reasons, Marseille area represents a challenging case study for source apportionment exercises, combining an active photochemistry and multiple emission sources, including fugitive emissions from industrial sources and shipping. In order to develop strategies for controlling and reducing air pollution, there is a need of source apportionment studies in order to better understand the influence of the different sources of aerosol particles. Within the framework of the EU-MED APICE project (Common Mediterranean strategy and local practical Actions for the mitigation of Port, Industries and Cities Emissions ; www.apice-project.eu), sources of atmospheric particles in Marseille were evaluated for a one-year period by a long monitoring campaign conducted at two sampling sites. PM2.5 were collected continuously on a 24h-basis in an urban background site from July 2011 to July 2012 and on a 48h-basis for the Eastern dock from November 2011 to July 2012 using high volume samplers (DA80) operating at a flow rate of 30m3 h-1. In this work, two different source apportionment models were used to explain the chemical observations, and to investigate the sources of organic aerosol in Marseille. Two sources apportionment models were used and combined to quantify the contribution of the main aerosol particles sources: CMB (Chemical Mass Balance) and PMF (Positive Matrix Factorization). Both models were used with organic molecular markers and metals/trace elements. Both approaches are able to identify major sources, the combination of these two commonly used receptor models offer interesting perspective, especially when the factors derived from PMF analysis are injected as source profiles in CMB calculation.

  6. Adsorption and reactions of atmospheric constituents and pollutants on ice particles: an FTIR study

    NASA Astrophysics Data System (ADS)

    Rudakova, A. V.; Marinov, I. L.; Poretskiy, M. S.; Tsyganenko, A. A.

    2009-04-01

    Processes on icy particles attract much attention due to their importance for atmospheric science, ecology and astrophysics. In this work, adsorption and ecologically important reactions of some molecules on pure and mixed water icy films by means of FTIR spectroscopy have been investigated. The cell for spectral studies of adsorbed molecules at variable temperatures (55-370 K), described elsewhere1, enables one to run the spectra in the presence of gaseous adsorbate, and even to perform adsorption from the solution in some cryogenic solvents. For the studies of ice films, it was equipped with a device for water vapour sputtering from the heated capillaries and deposition onto the inner BaF2 or ZnSe windows of the cell, cooled by liquid nitrogen. Lower temperatures were obtained by pumping off evaporating nitrogen from the coolant volume. The estimated specific surface area of freshly deposited at 77 K water ice film was about 160 m2/g and decreases on raising the temperature together with the diminishing intensity of the bands of dangling OH (OD) groups at 3696 (2727) cm-1 until the latter disappear at 130 - 160 K when the changes of bulk absorption provide evidence for a phase transition from amorphous to polycrystalline ice. CO adsorption at 77 K results in two bands at 2153 and 2137 cm-1 assigned to molecules forming weak H-bond with the dangling hydroxyl groups and bound to unsaturated surface oxygen atoms, respectively2. The band of dangling hydroxyl groups moves to lower wavenumbers on adsorption of different molecules (hydrogen, nitrogen, methane, ozone, NO, ethane or chlorinated ethenes, etc.). The shift value depends on the nature of adsorbate. Besides this shift, spectra of adsorbed nitrogen and methane registered at 55 K reveal the adsorption intensity decrease at ~ 2650 cm-1 at the high-frequency slope of bulk adsorption, and increase at about 25 cm-1 below. We interpret this perturbation as a strengthening of H-bonds between surface water molecules, which act as adsorption sites either as a proton-donor or as a donor of the lone pair of electrons. Such adsorption-induced relaxation explains the dependence of physico-chemical properties of icy particles on the presence of atmospheric gases. Spectra HCN/D2O and ND3/D2O mixed icy films with low (1:10) dopant/water ratios do not manifest any changes in the acidic or basic properties of dangling hydroxyl groups or surface oxygen atoms, but reveal a difference in the proportion between the concentrations of these sites as compared with that for pure water ice. For high dopant concentrations (1:1), the dangling hydroxyls were not observed; the dominant adsorption sites for CO are likely to be the unsaturated oxygen atoms, while serious structural changes occur in the bulk of ices. Ecologically important reactions of atmospheric pollutants such as ozonolysis of ethene, chlorinated ethenes, hydrogen cyanide, and methyl bromide adsorbed on water ice film as well as the influence of UV radiation on this process have been studied in 77 - 200 K temperature range by FTIR spectroscopy. Ozone co-adsorption with ethene or C2H3Cl readily leads to ozonolysis reaction, which also starts for C2H2Cl2 isomers but only at temperatures elevated up to 120 - 150 K. Co-adsorption of O3 with HCN or CH3Br molecules in the dark does not lead to any noticeable spectral changes. Irradiation of HCN or CH3Br deposited on ice films in the presence of ozone leads to appearance of new bands revealing the formation of ozonolysis products. The same "synergetic effect" of simultaneous action of ozone and UV radiation at 77 K, was found for C2H2Cl2 isomers and C2Cl4, which are resistant against O3 even at higher temperatures. The obtained spectral dependence of photo-ozonolysis of C2Cl4 and HCN at 77 K shows that photoexcitation or photodissociation of ozone, evidently, accounts for the observed processes. The surface of ice particles, thus, plays the role of a condenser of atmospheric pollutants and acts as a micro- photoreactor in the atmospheric chemistry. Acknowledgments. The work was supported by INTAS (grant 03-51-5698) and RFBR (grants 06-03-32836 and 06-05-64646). 1. Otero Areán С., Manoilova O.V., Tsyganenko A.A., Turnes Palomino G., Peñarroya Mentruit M., Geobaldo F., Garrone E. Eur. J. Inorg. Chem., 2001, No 7, 1739. 2. Rudakova A.V., Sekushin V.N., Marinov I.L., Tsyganenko A.A. Langmuir, 25 (2009) 000.

  7. "Sizing" Heterogeneous Chemistry in the Conversion of Gaseous Dimethyl Sulfide to Atmospheric Particles.

    PubMed

    Enami, Shinichi; Sakamoto, Yosuke; Hara, Keiichiro; Osada, Kazuo; Hoffmann, Michael R; Colussi, Agustín J

    2016-02-16

    The oxidation of biogenic dimethyl sulfide (DMS) emissions is a global source of cloud condensation nuclei. The amounts of the nucleating H2SO4(g) species produced in such process, however, remain uncertain. Hydrophobic DMS is mostly oxidized in the gas phase into H2SO4(g) + DMSO(g) (dimethyl sulfoxide), whereas water-soluble DMSO is oxidized into H2SO4(g) in the gas phase and into SO4(2-) + MeSO3(-) (methanesulfonate) on water surfaces. R = MeSO3(-)/(non-sea-salt SO4(2-)) ratios would therefore gauge both the strength of DMS sources and the extent of DMSO heterogeneous oxidation if Rhet = MeSO3(-)/SO4(2-) for DMSO(aq) + ·OH(g) were known. Here, we report that Rhet = 2.7, a value obtained from online electrospray mass spectra of DMSO(aq) + ·OH(g) reaction products that quantifies the MeSO3(-) produced in DMSO heterogeneous oxidation on aqueous aerosols for the first time. On this basis, the inverse R dependence on particle radius in size-segregated aerosol collected over Syowa station and Southern oceans is shown to be consistent with the competition between DMSO gas-phase oxidation and its mass accommodation followed by oxidation on aqueous droplets. Geographical R variations are thus associated with variable contributions of the heterogeneous pathway to DMSO atmospheric oxidation, which increase with the specific surface area of local aerosols. PMID:26761399

  8. Identifying organic aerosol sources by comparing functional group composition in chamber and atmospheric particles

    PubMed Central

    Russell, Lynn M.; Bahadur, Ranjit; Ziemann, Paul J.

    2011-01-01

    Measurements of submicron particles by Fourier transform infrared spectroscopy in 14 campaigns in North America, Asia, South America, and Europe were used to identify characteristic organic functional group compositions of fuel combustion, terrestrial vegetation, and ocean bubble bursting sources, each of which often accounts for more than a third of organic mass (OM), and some of which is secondary organic aerosol (SOA) from gas-phase precursors. The majority of the OM consists of alkane, carboxylic acid, hydroxyl, and carbonyl groups. The organic functional groups formed from combustion and vegetation emissions are similar to the secondary products identified in chamber studies. The near absence of carbonyl groups in the observed SOA associated with combustion is consistent with alkane rather than aromatic precursors, and the absence of organonitrate groups can be explained by their hydrolysis in humid ambient conditions. The remote forest observations have ratios of carboxylic acid, organic hydroxyl, and nonacid carbonyl groups similar to those observed for isoprene and monoterpene chamber studies, but in biogenic aerosols transported downwind of urban areas the formation of esters replaces the acid and hydroxyl groups and leaves only nonacid carbonyl groups. The carbonyl groups in SOA associated with vegetation emissions provides striking evidence for the mechanism of esterification as the pathway for possible oligomerization reactions in the atmosphere. Forest fires include biogenic emissions that produce SOA with organic components similar to isoprene and monoterpene chamber studies, also resulting in nonacid carbonyl groups in SOA. PMID:21317360

  9. Impacts of the Canadian forest fires on atmospheric mercury and carbonaceous particles in Northern New York.

    PubMed

    Wang, Yungang; Huang, Jiaoyan; Zananski, Tiffany J; Hopke, Philip K; Holsen, Thomas M

    2010-11-15

    The impact of Canadian forest fires in Quebec on May 31, 2010 on PM(2.5), carbonaceous species, and atmospheric mercury species was observed at three rural sites in northern New York. The results were compared with previous studies during a 2002 Quebec forest fire episode. MODIS satellite images showed transport of forest fire smoke from southern Quebec, Canada to northern New York on May 31, 2010. Back-trajectories were consistent with this regional transport. During the forest fire event, as much as an 18-fold increase in PM(2.5) concentration was observed. The concentrations of episode-related OC, EC, BC, UVBC, and their difference (Delta-C), reactive gaseous mercury (RGM), and particle-bound mercury (PBM) were also significantly higher than those under normal conditions, suggesting a high impact of Canadian forest fire emissions on air quality in northern New York. PBM, RGM, and Delta-C are all emitted from forest fires. The correlation coefficient between Delta-C and other carbonaceous species may serve as an indicator of forest fire smoke. Given the marked changes in PBM, it may serve as a more useful tracer of forest fires over distances of several hundred kilometers relative to GEM. However, the Delta-C concentration changes are more readily measured. PMID:20979360

  10. Modeling of in situ ultrafine atmospheric particle formation in the eastern United States

    NASA Astrophysics Data System (ADS)

    Gaydos, Timothy M.; Stanier, Charles O.; Pandis, Spyros N.

    2005-04-01

    The creation of new atmospheric particles from in situ nucleation influences climate through cloud-aerosol interactions and may negatively impact human health. Although recent observations show that nucleation is widespread in the eastern United States, the corresponding pathways remain uncertain. Combining extensive field measurements in Pittsburgh, Pennsylvania, with an aerosol dynamics and chemistry model assuming ternary NH3-H2SO4-H2O nuclei formation, we show excellent model-measurement agreement and predictive capability. The ternary NH3-H2SO4-H2O nucleation model is successful in predicting the presence or lack of nucleation on 19 out of 19 days with complete data sets in July 2001 and on 25 out of 29 days in January 2002. Reductions of ammonia emissions are predicted to decrease the frequency of nucleation events during both summer and winter, with a more dramatic effect during the summer. The response to changes in emissions of sulfur dioxide during the summer is counterintuitive. Reductions of sulfur dioxide and the resulting sulfate by up to 40% actually increase the frequency of the summer nucleation events. Modeling predicts the opposite effect in winter, with reductions of sulfur dioxide leading to fewer nucleation events.

  11. Absorption of Beta Particles in Different Materials: An Undergraduate Experiment

    ERIC Educational Resources Information Center

    La Rocca, Paola; Riggi, Francesco

    2009-01-01

    The absorption of beta rays from a radioactive source in different materials was investigated by the use of a simple setup based on a Geiger counter and a set of absorber sheets. The number of electrons traversing the material was measured as a function of its thickness. Detailed GEANT simulations were carried out to reproduce the obtained

  12. Absorption of Beta Particles in Different Materials: An Undergraduate Experiment

    ERIC Educational Resources Information Center

    La Rocca, Paola; Riggi, Francesco

    2009-01-01

    The absorption of beta rays from a radioactive source in different materials was investigated by the use of a simple setup based on a Geiger counter and a set of absorber sheets. The number of electrons traversing the material was measured as a function of its thickness. Detailed GEANT simulations were carried out to reproduce the obtained…

  13. Solid spherical glass particle impingement studies of plastic materials

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Young, S. G.; Buckley, D. H.

    1983-01-01

    Erosion experiments on polymethyl methacrylate (PMMA), polycarbonate, and polytetrafluoroethylene (PTFE) were conducted with spherical glass beads impacting at normal incidence. Optical and scanning electron microscopic studies and surface profile measurements were made on specimens at predetermined test intervals. During the initial stage of damage to PMMA and polycarbonate, material expands or builds up above the original surface. However, this buildup disappears as testing progresses. Little or no buildup was observed on PTFE. PTFE is observed to be the most resistant material to erosion and PMMA the least. At low impact pressures, material removal mechanisms are believed to be similar to those for metallic materials. However, at higher pressures, surface melting is indicated at the center of impact. Deformation and fatigue appear to play major roles in the material removal process with possible melting or softening.

  14. Effect of ions on sulfuric acid-water binary particle formation: 1. Theory for kinetic- and nucleation-type particle formation and atmospheric implications

    NASA Astrophysics Data System (ADS)

    Merikanto, Joonas; Duplissy, Jonathan; Määttänen, Anni; Henschel, Henning; Donahue, Neil M.; Brus, David; Schobesberger, Siegfried; Kulmala, Markku; Vehkamäki, Hanna

    2016-02-01

    We derive a version of Classical Nucleation Theory normalized by quantum chemical results on sulfuric acid-water hydration to describe neutral and ion-induced particle formation in the binary sulfuric acid-water system. The theory is extended to treat the kinetic regime where the nucleation free energy barrier vanishes at high sulfuric acid concentrations or low temperatures. In the kinetic regime particle formation rates become proportional to sulfuric acid concentration to second power in the neutral system or first power in the ion-induced system. We derive simple general expressions for the prefactors in kinetic-type and activation-type particle formation calculations applicable also to more complex systems stabilized by other species. The theory predicts that the binary water-sulfuric acid system can produce strong new particle formation in the free troposphere both through barrier crossing and through kinetic pathways. At cold stratospheric and upper free tropospheric temperatures neutral formation dominates the binary particle formation rates. At midtropospheric temperatures the ion-induced pathway becomes the dominant mechanism. However, even the ion-induced binary mechanism does not produce significant particle formation in warm boundary layer conditions, as it requires temperatures below 0°C to take place at atmospheric concentrations. The theory successfully reproduces the characteristics of measured charged and neutral binary particle formation in CERN CLOUD3 and CLOUD5 experiments, as discussed in a companion paper.

  15. First Measurements of Neutral Atmospheric Cluster and 12 nm Particle Number Size Distributions During Nucleation Events

    SciTech Connect

    Jiang, J.; Kuang, C.; Zhao, J.; Chen, M.; Eisele, F. L.; Scheckman, J.; Williams, B. J.; McMurry, P. H.

    2011-02-01

    Recent observations throughout the atmosphere have shown that nucleation occurs frequently (Kulmala et al. 2004). Modeling studies and observations have shown that nucleated particles contribute significantly to concentrations of cloud condensation nuclei (Spracklen et al. 2008), thereby affecting climate (IPCC 2007). Size-resolved measurements extending down to molecular dimensions can provide information on processes that lead to nucleation and would enable development and verification of theories for particle nucleation and growth in the atmosphere and other aerosol systems. This article describes measurements of the complete number size distribution, spanning the size range from vapor molecules and molecular clusters to submicrometer particles, during atmospheric nucleation events. The measurements used two new instruments, the cluster chemical ionization mass spectrometer (Cluster CIMS) and the DEG SMPS. The Cluster CIMS measures neutral molecular clusters from 50 to 900 amu. The DEG SMPS is a scanning mobility particle spectrometer (SMPS) equipped with a diethylene glycol (DEG)-based condensation particle counter (CPC) capable of 1.1 nm mobility diameter particle detection, and overlapping the sizes detected by the Cluster CIMS (Iida et al. 2009; Jiang et al. 2011). The Cluster CIMS distinguishes neutral clusters from ions formed by ion-induced clustering by varying the reaction time for ions with the sampled air (Zhao et al. 2010). It distinguishes clusters from high molecular weight gases by measuring the incremental signal at a specified mass detected during nucleation events. The clusters that were measured in this study contain sulfuric acid, which is known to participate in atmospheric nucleation (Kuang et al. 2008).

  16. Dynamics of Granular Materials and Particle-Laden Flows

    SciTech Connect

    Swinney, Harry L.

    2007-07-11

    Rapid granular flows and particle-laden flows were studied in laboratory experiments, molecular dynamics simulations, and simulations of continuum equations. The research demonstrated that the inclusion of friction is crucial in realistic modeling of granular flows; hence extensive previous analyses and simulations by many researchers for frictionless particles must be reconsidered in the light of our work. We also made the first detailed comparison between experiment and the predictions of continuum theory for granular media (hydrodynamic equations). We found that shock waves easily form in granular flows since the speed of sound waves (pressure fluctuations) in a granular gas is small, typically 10 cm, while flow velocities are easily an order of magnitude larger. Our measurements on vertically oscillating granular layers led to the development of a novel technique for continuously separating particles of different sizes. Our study of craters formed by the impact of a projectile in a granular medium showed, surprisingly, that the time taken for a projectile to come to a rest in the granular layer is independent of the projectile’s impact energy. Another study supported by this grant examined a vertically oscillating layer of a mixture of cornstarch and water. The discovery of stable holes in the mixture was reported widely in the popular press, e.g., Science News [15 May 2004], “Imaging poking a liquid to create holes that persist like the holes in Swiss cheese. Incredible as that might sound, a group of scientists has done it.” Further experiments on glass spheres in an aqueous solution yielded the same holey fluid phenomenon, supporting our conjecture that such holes may occur in dense concentrations of particles in solution in industrial applications.

  17. Photons and particles emitted from cold atmospheric-pressure plasma inactivate bacteria and biomolecules independently and synergistically

    PubMed Central

    Lackmann, Jan-Wilm; Schneider, Simon; Edengeiser, Eugen; Jarzina, Fabian; Brinckmann, Steffen; Steinborn, Elena; Havenith, Martina; Benedikt, Jan; Bandow, Julia E.

    2013-01-01

    Cold atmospheric-pressure plasmas are currently in use in medicine as surgical tools and are being evaluated for new applications, including wound treatment and cosmetic care. The disinfecting properties of plasmas are of particular interest, given the threat of antibiotic resistance to modern medicine. Plasma effluents comprise (V)UV photons and various reactive particles, such as accelerated ions and radicals, that modify biomolecules; however, a full understanding of the molecular mechanisms that underlie plasma-based disinfection has been lacking. Here, we investigate the antibacterial mechanisms of plasma, including the separate, additive and synergistic effects of plasma-generated (V)UV photons and particles at the cellular and molecular levels. Using scanning electron microscopy, we show that plasma-emitted particles cause physical damage to the cell envelope, whereas UV radiation does not. The lethal effects of the plasma effluent exceed the zone of physical damage. We demonstrate that both plasma-generated particles and (V)UV photons modify DNA nucleobases. The particles also induce breaks in the DNA backbone. The plasma effluent, and particularly the plasma-generated particles, also rapidly inactivate proteins in the cellular milieu. Thus, in addition to physical damage to the cellular envelope, modifications to DNA and proteins contribute to the bactericidal properties of cold atmospheric-pressure plasma. PMID:24068175

  18. Source identification of lead pollution in the atmosphere of Shanghai City by analyzing single aerosol particles (SAP)

    SciTech Connect

    Wang, J.; Guo, P.; Li, X.

    2000-05-15

    A new method combining the pattern recognition (PR) technique with micro-PIXE spectrum was used for direct assessment of lead pollution in the atmosphere of Shanghai City. Single aerosol particles (SAP) of PM{sub 10} (<10 {micro}m) were analyzed using the nuclear microprobe. Every particle is characterized with its micro-PICE spectrum, which can be considered its fingerprint. The PR technique was applied to trace a lead contaminated aerosol particle back to its source. The discrimination of different pollutant sources was enhanced with investigating the individual aerosol particles. The results showed that the lead contamination from automobile exhaust should not be neglected. The lead concentration with low level was detected in most unleaded gasoline particles; however, the highest lead level of 1,500 ppm was found in one of them. Furthermore, four other main pollutant sources contributing to the lead contamination in the Shanghai atmosphere were clearly identified by this method. They are the cement industry, the coal combustion, the oil combustion, and the metallurgic industry. Some other unidentified particles suggested that some more lead emitters might also exist in Shanghai.

  19. Heterogeneous Combustion Particles with Distinctive Light-Absorbing and Light-Scattering Phases as Mimics of Internally-Mixed Ambient Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Conny, J. M.; Ma, X.; Gunn, L. R.

    2011-12-01

    Particles with heterogeneously-distributed light-absorbing and light-scattering phases were generated from incomplete combustion or thermal decomposition to mimic real atmospheric particles with distinctive optical properties. Individual particles and particle populations were characterized microscopically. The purpose was to examine how optical property measurements of internally-mixed ambient air particles might vary based on the properties of laboratory-generated particles produced under controlled conditions. The project is an initial stage in producing reference samples for calibrating instrumentation for monitoring climatically-important atmospheric aerosols. Binary-phase particles containing black carbon (BC) and a metal or a metal oxide phase were generated from the thermal decomposition or partial combustion of liquid fuels at a variety of temperatures from 600 °C to 1100 °C. Fuels included mixtures of toluene or isooctane and iron pentacarbonyl or titanium tetrachloride. Scanning electron microscopy with energy-dispersive x-ray spectroscopy revealed that burning the fuels at different temperatures resulted in distinctive differences in morphology and carbon vs. metal/metal oxide composition. Particles from toluene/Fe(CO)5 thermal decomposition exhibited aggregated morphologies that were classified as dendritic, soot-like, globular, or composited (dendritic-globular). Particles from isooctane/TiCl4 combustion were typically spherical with surface adducts or aggregates. Diameters of the BC/TiO2 particles averaged 0.68 μm to 0.70 μm. Regardless of combustion temperature, the most abundant particles in each BC/TiO2 sample had an aspect ratio of 1.2. However, for the 600 °C and 900 °C samples the distribution of aspect ratios was skewed toward much larger ratios suggesting significant chainlike aggregation. Carbon and titanium compositions (wt.) for the 600 °C sample were 12 % and 53 %, respectively. In contrast, the composition trended in the opposite direction for the 900 °C sample with carbon at 57 % and titanium at 27 %.

  20. Interplanetary dust particles collected in the stratosphere: observations of atmospheric heating and constraints on their interrelationships and sources.

    PubMed

    Sandford, S A; Bradley, J P

    1989-01-01

    The majority of the interplanetary dust particles (IDPs) collected in the stratosphere belong to one of three major classes, the first two dominated by the anhydrous minerals olivine and pyroxene, and the third by hydrous layer-lattice silicates. Infrared spectroscopy and transmission electron microscopy studies show that the different IDP classes represent different types of dust that exist as individual particles in interplanetary space. The majority of the collected IDPs smaller than 30 micrometers in diameter in the layer-lattice silicate and pyroxene classes appear not to have been heated to temperatures above 600 degrees C during atmospheric entry. The relatively low maximum temperatures experienced by these IDPs during atmospheric entry imply that they arrive at the top of the atmosphere with low geocentric encounter velocities. This limits the possible encounter trajectories for these particles to relatively circular, prograde orbits. As a result, it is unlikely that these IDPs are from Earth-crossing comets or asteroids. Asteroids, and comets having low inclinations and perihelia outside 1.2 AU, appear to be the best candidates for the parent bodies of the pyroxene and layer-lattice silicate particles. Chemical and mineralogical information suggests that the pyroxene-rich IDPs are from comets and the layer-lattice silicate-rich IDPs are from asteroids. The collected IDPs dominated by olivine appear to include a larger fraction of particles heating above 600 degrees C, suggesting that these particles were captured from more eccentric orbits. This, and the observation of the infrared spectral features of olivine in several comets suggest these particles have a cometary origin. Since much of the collected dust has apparently been captured from nearly circular, prograde orbits and since there are no appropriate parent bodies presently in such orbits, these results provide an experimental confirmation that the Poynting-Robertson effect exists as a nongravitational force important in the orbital evolution of dust in the Solar System. PMID:11538675

  1. 29 CFR 1917.23 - Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or atmosphere). 1917.23 Section 1917.23 Labor Regulations Relating to... TERMINALS Marine Terminal Operations § 1917.23 Hazardous atmospheres and substances (see also §...

  2. 29 CFR 1917.23 - Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or atmosphere). 1917.23 Section 1917.23 Labor Regulations Relating to... TERMINALS Marine Terminal Operations § 1917.23 Hazardous atmospheres and substances (see also §...

  3. 29 CFR 1917.23 - Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or atmosphere). 1917.23 Section 1917.23 Labor Regulations Relating to... TERMINALS Marine Terminal Operations § 1917.23 Hazardous atmospheres and substances (see also §...

  4. 29 CFR 1917.23 - Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or atmosphere). 1917.23 Section 1917.23 Labor Regulations Relating to... TERMINALS Marine Terminal Operations § 1917.23 Hazardous atmospheres and substances (see also §...

  5. 29 CFR 1917.23 - Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Hazardous atmospheres and substances (see also § 1917.2 Hazardous cargo, material, substance or atmosphere). 1917.23 Section 1917.23 Labor Regulations Relating to... TERMINALS Marine Terminal Operations § 1917.23 Hazardous atmospheres and substances (see also §...

  6. Effect of atmospheric fine particles on epidermal growth factor receptor mRNA expression in mouse skin tissue.

    PubMed

    Han, X; Liang, W L; Zhang, Y; Sun, L D; Liang, W Y

    2016-01-01

    We investigated the effect of atmospheric fine particles on epidermal growth factor receptor (Egfr) mRNA expression in mouse skin tissue and explored the effect of atmospheric fine particles on skin aging. Forty female BALB/c mice were randomly divided into four groups (each comprising 10 mice) as follows: a saline control group and low-, medium-, and high-dose atmospheric fine particle groups (1.6, 8.0, and 40.0 mg/kg, respectively) (fine particles were defined as those with a diameter of £2.5 mm, i.e., PM2.5). Each dose group was exposed to intratracheal instillation for 3 days. Twenty-four hours after the last exposure, real-time quantitative polymerase chain reaction was used to detect the expression of Egfr mRNA in the skin tissue of each mouse. The expression levels of Egfr mRNA in the medium- and high-dose PM2.5 groups were significantly higher (P < 0.05) than that in the control group, and were positively correlated with the dose. Medium and high concentrations of PM2.5 can induce the expression of Egfr mRNA and promote skin aging. PMID:27050971

  7. Angular particle impingement studies of thermoplastic materials at normal incidence

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Buckley, D. H.

    1985-01-01

    Scanning electron microscope studies were conducted to characterize the erosion resistance of polymethyl methacrylate (PMMA), polycarbonate (PC), polytetrafluorethylene (PTFE), and ultra-high-molecular-weight polyethylene (UHMWPE). Erosion was caused by a jet of angular microparticles of crushed glass at normal incidence. Material built up above the original surface on all of the materials. As erosion progressed, this buildup disappeared. UHMWPE was the most resistant material and PMMA the least. The most favorable properties for high erosion resistance were high values of ultimate elongation, maximum service temperature, and strain energy and a low value of the modulus of elasticity. Erosion-rate-versus-time curves of PC and PTFE exhibited incubation, acceleration, and steady-state periods. PMMA also exhibited a deceleration period, and an incubation period with deposition was observed for UHMWPE.

  8. Air Quality Impacts of Atmospheric Particles & Trace Gases: Field Studies in Diverse Environments

    NASA Astrophysics Data System (ADS)

    Mwaniki, George R.

    Air pollution impacts occur at all scales, meaning that policies and air quality management practices must be implemented and coordinated at the local, regional, national, and global scales. This dissertation is part of a continuing effort to improve our understanding of various air quality related issues in different environments. The dissertation consists of four studies. In the first study, wintertime chemical composition of water-soluble particulate matter with aerodynamic diameter less than 2.5 microm (PM2.5) was monitored in the Treasure Valley region near Boise, Idaho. This study was aimed at understanding the major drivers of wintertime PM2.5 within the locality of Boise and its suburbs. From this study, organics and particulate nitrate were the dominant contributors to the PM2.5 mass during wintertime. In the second study, particle size distribution, light scattering coefficient, speciated water soluble PM2.5, and cloud condensation nuclei (CCN) concentration were monitored in a mixed deciduous forest in Northern Michigan during the Community Atmosphere-Biosphere Interactions Experiment (CABINEX-2009). The overall goal of this study was to understand on how emissions of biogenic volatile organic compounds (BVOC) affect the gas-phase and particle-phase chemistry in the near-canopy environment, and the implications on local and regional air quality. From this study aerosol derived from the oxidation of BVOCs exhibited reduced hygroscopicity and CCN activation potential compared to aerosols derived from anthropogenic activities. The third study employed the eddy covariance (EC) technique to understand source-sink interactions of carbon dioxide (CO2), methane (CH 4), carbon monoxide (CO) and nitrous oxide (N2O) in Xi'an, China. In this study urban vegetation were found to play a major role in regulating CO2 emissions within the city while vehicular activities were a major driver for CO and CH4 fluxes. In the fourth study, visibility degradation effects of nitrogen oxide (NO) and nitrogen dioxide (NO2) emissions from a natural gas compressing facility in southern Idaho were evaluated and quantified. In addition, several retrofit technologies were evaluated based to their ability to reduce NOx (NO + NO2) emissions. From this study selective catalytic reduction (SCR) was found to be the most appropriate technology to reduce NOx emissions from the facility.

  9. Thermal conductivity measurements of particulate materials: 3. Natural samples and mixtures of particle sizes

    NASA Astrophysics Data System (ADS)

    Presley, Marsha A.; Craddock, Robert A.

    2006-09-01

    A line-heat source apparatus was used to measure thermal conductivities of natural fluvial and eolian particulate sediments under low pressures of a carbon dioxide atmosphere. These measurements were compared to a previous compilation of the dependence of thermal conductivity on particle size to determine a thermal conductivity-derived particle size for each sample. Actual particle-size distributions were determined via physical separation through brass sieves. Comparison of the two analyses indicates that the thermal conductivity reflects the larger particles within the samples. In each sample at least 85-95% of the particles by weight are smaller than or equal to the thermal conductivity-derived particle size. At atmospheric pressures less than about 2-3 torr, samples that contain a large amount of small particles (<=125 μm or 4 Φ) exhibit lower thermal conductivities relative to those for the larger particles within the sample. Nonetheless, 90% of the sample by weight still consists of particles that are smaller than or equal to this lower thermal conductivity-derived particle size. These results allow further refinement in the interpretation of geomorphologic processes acting on the Martian surface. High-energy fluvial environments should produce poorer-sorted and coarser-grained deposits than lower energy eolian environments. Hence these results will provide additional information that may help identify coarser-grained fluvial deposits and may help differentiate whether channel dunes are original fluvial sediments that are at most reworked by wind or whether they represent a later overprint of sediment with a separate origin.

  10. Interactions of mineral dust with pollution and clouds: An individual-particle TEM study of atmospheric aerosol from Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Pósfai, Mihály; Axisa, Duncan; Tompa, Éva; Freney, Evelyn; Bruintjes, Roelof; Buseck, Peter R.

    2013-03-01

    Aerosol particles from desert dust interact with clouds and influence climate on regional and global scales. The Riyadh (Saudi Arabia) aerosol campaign was initiated to study the effects of dust particles on cloud droplet nucleation and cloud properties. Here we report the results of individual-particle studies of samples that were collected from an aircraft in April 2007. We used analytical transmission electron microscopy, including energy-dispersive X-ray spectrometry, electron diffraction, and imaging techniques for the morphological, chemical, and structural characterization of the particles. Dust storms and regional background conditions were encountered during four days of sampling. Under dusty conditions, the coarse (supermicrometer) fraction resembles freshly crushed rock. The particles are almost exclusively mineral dust grains and include common rock-forming minerals, among which clay minerals, particularly smectites, are most abundant. Unaltered calcite grains also occur, indicating no significant atmospheric processing. The particles have no visible coatings but some contain traces of sulfur. The fine (submicrometer) fraction is dominated by particles of anthropogenic origin, primarily ammonium sulfate (with variable organic coating and some with soot inclusions) and combustion-derived particles (mostly soot). In addition, submicrometer, iron-bearing clay particles also occur, many of which are internally mixed with ammonium sulfate, soot, or both. We studied the relationships between the properties of the aerosol and the droplet microphysics of cumulus clouds that formed above the aerosol layer. Under dusty conditions, when a large concentration of coarse-fraction mineral particles was in the aerosol, cloud drop concentrations were lower and droplet diameters larger than under regional background conditions, when the aerosol was dominated by submicrometer sulfate particles.

  11. Organophosphate and halogenated flame retardants in atmospheric particles from a European Arctic site.

    PubMed

    Salamova, Amina; Hermanson, Mark H; Hites, Ronald A

    2014-06-01

    Levels of 13 organophosphate esters (OPEs) and 45 brominated and chlorinated flame retardants (BFRs) were measured in particle phase atmospheric samples collected at Longyearbyen on Svalbard in the European Arctic from September 2012 to May 2013. Total OPE (ΣOPEs) concentrations ranged from 33 to 1450 pg/m3, with the mean ΣOPE concentration of 430±57 pg/m3. The nonchlorinated tri-n-butyl phosphate (TnBP) and 2-ethylhexyl-diphenyl phosphate (EHDPP) were the most abundant OPE congeners measured, and the sum of all nonchlorinated OPE concentrations comprised ∼75% of the ΣOPE concentrations. The most abundant chlorinated OPE was tris(1-chloro-2-propyl) phosphate (TCPP). Total BFR concentrations (ΣBFRs) were in the range of 3-77 pg/m3, with a mean concentration of 15±3 pg/m3. 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) and bis(2-ethylhexyl)tetrabromophthalate (TBPH) were among the relatively abundant BFRs measured in these samples and comprised ∼46% and 17% of ΣBFR concentrations, respectively. Total PBDE (ΣPBDE) concentrations constituted ∼37% of ΣBFR concentrations on average and ranged from 1 to 31 pg/m3. The most abundant PBDE congener was BDE-209, which contributed 24% to ΣPBDE concentrations. Dechlorane Plus (DP) was detected in all of the samples, and ΣDP concentrations (syn-+anti-DP concentrations) ranged from 0.05 to 5 pg/m3. Overall, ΣOPE concentrations were 1-2 orders of magnitude higher than the ΣBFR concentrations. PMID:24848787

  12. Acidic reaction products of monoterpenes and sesquiterpenes in atmospheric fine particles in a boreal forest

    NASA Astrophysics Data System (ADS)

    Vestenius, M.; Hellén, H.; Levula, J.; Kuronen, P.; Helminen, K. J.; Nieminen, T.; Kulmala, M.; Hakola, H.

    2014-08-01

    Biogenic acids were measured in aerosols at the SMEAR II (Station for Measuring Forest Ecosystem-Atmosphere Relations II) station in Finland from June 2010 until October 2011. The analysed organic acids were pinic, pinonic, caric, limonic and caryophyllinic acids from oxidation of α-pinene, β-pinene, limonene, Δ3-carene and β-caryophyllene, respectively. Due to a lack of authentic standards, the caric, limonic and caryophyllinic acids were synthesised for this study. The mean, median, maximum and minimum concentrations (ng m-3) were as follows: limonic acid (1.26, 0.80, 16.5, below detection limit (< LOD)), pinic acid (5.53, 3.25, 31.4, 0.15), pinonic acid (9.87, 5.07, 80.1, < LOD), caric acid (5.52, 3.58, 49.8, < LOD), and caryophyllinic acid (7.87, 6.07, 86.1, < LOD). The highest terpenoic acid concentrations were measured during the summer. Of the acids, β-caryophyllinic acid showed the highest concentrations in summer, but during other times of the year pinonic acid was the most abundant. The β-caryophyllinic acid contribution was higher than expected, based on the emission calculations of the precursor compounds and yields from oxidation experiments in smog chambers, implying that the β-caryophyllene emissions or β-caryophyllinic acid yields were underestimated. The concentration ratios between terpenoic acids and their precursors were clearly lower in summer than in winter, indicating stronger partitioning to the aerosol phase during the cold winter season. The β-caryophyllinic and caric acids were weakly correlated with the accumulation-mode particle number concentrations.

  13. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Petzold, A.; Hasselbach, J.; Lauer, P.; Baumann, R.; Franke, K.; Gurk, C.; Schlager, H.; Weingartner, E.

    2008-05-01

    Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B&W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transformation studies in the plume of a large container ship in the English Channel using the DLR aircraft Falcon 20 E-5. Observations from emission studies and plume studies combined with a Gaussian plume dispersion model yield a consistent picture of particle transformation processes from emission to atmospheric processing during plume expansion. Particulate matter emission indices obtained from plume measurements are 8.8±1.0×1015(kg fuel)-1 by number for non-volatile particles and 174±43 mg (kg fuel)-1 by mass for Black Carbon (BC). Values determined for test rig conditions between 85 and 110% engine load are of similar magnitude. For the total particle number including volatile compounds no emission index can be derived since the volatile aerosol fraction is subject to rapid transformation processes in the plume. Ship exhaust particles occur in the size range Dp<0.3 μm, showing a bi-modal structure. The combustion particle mode is centred at modal diameters of 0.05 μm for raw emissions to 0.10 μm at a plume age of 1 h. The smaller-sized volatile particle mode is centred at Dp≤0.02 μm. From the decay of ship exhaust particle number concentrations in an expanding plume, a maximum plume life time of approx. 24 h is estimated for a well-mixed marine boundary layer.

  14. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Petzold, A.; Hasselbach, J.; Lauer, P.; Baumann, R.; Franke, K.; Gurk, C.; Schlager, H.; Weingartner, E.

    2007-10-01

    Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B&W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transformation studies in the plume of a large container ship in the English Channel using the DLR aircraft Falcon 20 E-5. Observations from emission studies and plume studies combined with a Gaussian plume dispersion model yield a consistent picture of particle transformation processes from emission to atmospheric processing during plume expansion. Particulate matter emission indices obtained from plume measurements are 8.8±1.0×1015(kg fuel)-1 by number for non-volatile particles and 174±43 mg (kg fuel)-1 by mass for Black Carbon (BC). Values determined for test rig conditions between 85 and 110% engine load are of similar magnitude. For the total particle number including volatile compounds no emission index can be derived since the volatile aerosol fraction is subject to rapid transformation processes in the plume. Ship exhaust particles occur in the size range Dp<0.3 μm, showing a bi-modal structure. The combustion particle mode is centred at modal diameters of 0.05 μm for raw emissions to 0.10 μm at a plume age of 1 h. The smaller-sized volatile particle mode is centred at Dp≤0.02 μm. From the decay of ship exhaust particle number concentrations in an expanding plume, a maximum plume life time of approx. 24 h is estimated for a well-mixed marine boundary layer.

  15. Material removal mechanism and material removal rate model of polishing process for quartz glass using soft particle

    NASA Astrophysics Data System (ADS)

    Liu, Defu; Chen, Guanglin; Hu, Qing

    2015-10-01

    Fiber arrays are used to connect arrayed waveguide chips. The end-faces of fiber array components are multi-materials non-uniform surfaces. Their low polishing quality has become a bottleneck that restricts coupling performance of integrated photo-electronic devices. The chemical mechanical polishing (CMP) is normally used to improve the polishing quality of the end-faces of fiber array components. It is very important to optimize process parameters by researching the mechanical behavior of nanoparticles and material microstructure evolution on the CMP interfaces. Based on the elastic and hyper-elastic contact of the soft polishing particle with quartz glass and polishing pad, the material removal mechanism at molecular scale of polishing process for quartz glass using soft polishing particles is investigated, and the material removal rate model is also derived by using Arrhenius theory and molecule vibration theory. Theoretical and experimental results show that the material is mainly removed by the interfacial tribo-chemical effect between polishing particle and quartz glass during CMP process. The depth of a single particle embedding into the quartz glass is at molecular scale, and the superficial molecules of quartz glass are removed by chemical reactions because of enough energy obtained. The material removal rate of quartz glass during CMP process is determined by the polishing pressure, the chemical reagents and its concentration, and the relative movement speed between the quartz glass workpiece and the polishing pad.

  16. Insights on Sources, Growth, and Phase Partitioning of Atmospheric Particles from Hourly Measurements of Organic Marker Compounds

    NASA Astrophysics Data System (ADS)

    Williams, B.; Goldstein, A.; Kreisberg, N.; Hering, S.; Docherty, K.; Jimenez, J.; Shields, L.; Qin, X.; Prather, K.; Ziemann, P.

    2007-12-01

    Atmospheric aerosols have adverse affects on human health and have direct and indirect affects on the global radiation balance. In order to implement particle concentration control strategies, we must first understand particle origins. Atmospheric aerosols have both primary sources such as combustion processes and secondary sources such as photochemically driven gas to particle phase partitioning. By monitoring changes in the molecular composition of the organic fraction of atmospheric aerosols, these various sources can be differentiated. Thermal desorption Aerosol Gas chromatography (TAG) is a new in-situ instrument capable of identifying and quantifying organic aerosol chemical composition with one hour time resolution. TAG is fully automated, offering around the clock measurements to determine diurnal, weekly, and seasonal patterns in organic aerosol composition, hence, determining aerosol sources and transformation processes. We report results from ambient measurements made in Southern California during the summer and fall of 2005 as part of the Study of Organic Aerosol at Riverside (SOAR). We use hourly measurements of over 300 individual organic compounds to define both primary and secondary particle sources. The particle sources defined include primary anthropogenic sources such as vehicle emissions, meat cooking, biomass burning, pesticide use, herbicide use, along with primary biogenic sources such as plant emissions and plant waxes. We also explore secondary particle sources (i.e. SOA) formed as a result of the oxidation of biogenic and anthropogenic precursor gases. Comparisons are made between TAG-defined sources and aerosol sources defined using Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) and Aerosol Mass Spectrometer (AMS) data. In addition to source apportionment results, we present seasonal changes in ambient phase partitioning of organic compounds as a function of carbon number for multiple compound classes.

  17. Gas/particle partitioning of polycyclic aromatic hydrocarbons in coastal atmosphere of the north Yellow Sea, China.

    PubMed

    Wang, Zhen; Ren, Peifang; Sun, Yan; Ma, Xindong; Liu, Xing; Na, Guangshui; Yao, Ziwei

    2013-08-01

    Samples of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) were collected at three sampling stations (Xiaomai Island, Laohutan, and Zhangzi Island) in the north Yellow Sea, China during November 2008 and September 2009 to study their atmospheric transport potential and the gas/particle distributions. The composition of PAHs was dominated by gaseous compounds. The percentages of the particle-phase PAHs to the total concentrations were found to be higher during the heating period than the non-heating period. The ratios of naphthalene and acenaphthene to phenanthrene, chrysene and dibenzo(a,h)anthracene showed an increasing trend from Xiaomai Island to Zhangzi Island, which can be called as the local atmospheric distillation of PAHs. Gas/particle partitioning coefficients (K p) and their relationship with the sub-cooled liquid vapor pressures (pºL) of PAHs were investigated. The regressions of logK p versus logpºL gave significant correlations for all samples of the three sites with r (2) values in the range 0.56-0.66 (p<0.01). Both Junge-Pankow adsorption model and octanol-air partition coefficient absorption model tended to underestimate the sorption for most PAHs, but the absorption model appeared to be more suitable for predicting the particle fraction of PAHs than the Junge-Pankow model. PMID:23463281

  18. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... atmosphere, except pipelines under paragraph (c) of this section. (b) Coating material must be suitable...

  19. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... atmosphere, except pipelines under paragraph (c) of this section. (b) Coating material must be suitable...

  20. 49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... atmosphere, except pipelines under paragraph (c) of this section. (b) Coating material must be suitable...

  1. Using Atmospheric Dispersion Theory to Inform the Design of a Short-lived Radioactive Particle Release Experiment.

    PubMed

    Rishel, Jeremy P; Keillor, Martin E; Arrigo, Leah M; Baciak, James E; Detwiler, Rebecca S; Kernan, Warnick J; Kirkham, Randy R; Milbrath, Brian D; Seifert, Allen; Seifert, Carolyn E; Smart, John E

    2016-05-01

    Atmospheric dispersion theory can be used to predict ground deposition of particulates downwind of a radionuclide release. This paper uses standard formulations found in Gaussian plume models to inform the design of an experimental release of short-lived radioactive particles into the atmosphere. Specifically, a source depletion algorithm is used to determine the optimum particle size and release height that maximizes the near-field deposition while minimizing both the required source activity and the fraction of activity lost to long-distance transport. The purpose of the release is to provide a realistic deposition pattern that might be observed downwind of a small-scale vent from an underground nuclear explosion. The deposition field will be used, in part, to study several techniques of gamma radiation survey and spectrometry that could be used by an On-Site Inspection team investigating such an event. PMID:27023039

  2. Wood dust particle and mass concentrations and filtration efficiency in sanding of wood materials.

    PubMed

    Welling, Irma; Lehtimäki, Matti; Rautio, Sari; Lähde, Tero; Enbom, Seppo; Hynynen, Pasi; Hämeri, Kaarle

    2009-02-01

    The importance of fine particles has become apparent as the knowledge of their effects on health has increased. Fine particle concentrations have been published for outside air, plasma arc cutting, welding, and grinding, but little data exists for the woodworking industry. Sanding was evaluated as the producer of the woodworking industry's finest particles, and was selected as the target study. The number of dust particles in different particle size classes and the mass concentrations were measured in the following environments: workplace air during sanding in plywood production and in the inlet and return air; in the dust emission chamber; and in filter testing. The numbers of fine particles were low, less than 10(4) particles/cm(3) (10(7) particles/L). They were much lower than typical number concentrations near 10(6) particles/cm(3) measured in plasma arc cutting, grinding, and welding. Ultrafine particles in the size class less than 100 nm were found during sanding of MDF (medium density fiberboard) sheets. When the cleaned air is returned to the working areas, the dust content in extraction systems must be monitored continuously. One way to monitor the dust content in the return air is to use an after-filter and measure pressure drop across the filter to indicate leaks in the air-cleaning system. The best after-filtration materials provided a clear increase in pressure drop across the filter in the loading of the filter. The best after-filtration materials proved to be quite effective also for fine particles. The best mass removal efficiencies for fine particles around 0.3 mum were over 80% for some filter materials loaded with sanding wood dust. PMID:19065389

  3. Parameter estimation approach for particle flow model of rockfill materials using response surface method

    NASA Astrophysics Data System (ADS)

    Li, Shouju; Li, De; Cao, Lijuan; Shangguan, Zichang

    2015-02-01

    Particle flow code (PFC) is widely used to model deformation and stress states of rockfill materials. The accuracy of numerical modeling with PFC is dependent upon the model parameter values. How to accurately determine model parameters remains one of the main challenges. In order to determine model parameters of particle flow model of rockfill materials, some triaxial compression experiments are performed, and the inversion procedure of model parameters based on response surface method is proposed. Parameters of particle flow model of rockfill materials are determined according to the observed data in triaxial compression tests for rockfill materials. The investigation shows that the normal stiffness, tangent stiffness and friction coefficient of rockfill materials will slightly increase with increase of confining pressure in triaxial compression tests. The experiments in laboratory show that the proposed inversion procedure behaves higher computing efficiency and the forecasted stress-strain relations agree well with observed values.

  4. In vitro macrophage response to nanometer-size particles from materials used in hip implants

    NASA Astrophysics Data System (ADS)

    VanOs, Robilyn

    Wear particle-induced inflammation leading to periprosthetic osteolysis remains a major cause of hip implant failure. As polyethylene particles from conventional metal-on-polyethylene implants have been associated with these failures, an interest in lower wear metal-on-metal (MM) bearings has emerged. However, the biological effects of nanometer-size chromium oxide particles, predominant type of wear particles produced by MM implants, remain mostly unknown. Therefore, this study aimed to determine the cytotoxicity of nanometer-size Cr2O3 particles on macrophages in vitro, by analyzing their effects on cell mortality and cytokine release and comparing them with those of similarly-sized alumina (Al2O3) particles (known to be relatively bioinert). Results showed that at high concentrations, nanometer-size Cr2O3 particles can be cytotoxic to macrophages, inducing significant decreases in total cell numbers and increases in necrosis. Results also showed that, at high concentrations, the cytotoxicity of Cr 2O3 particles was overall higher than that of Al2O 3 particles, even though Cr2O3 and Al2O 3 are both stable forms of ceramic materials. However, it appeared to be lower than that of previously reported conventional polyethylene and CoCrMo particles. Therefore, chromium oxide particles may not be the main culprit in initiating the inflammatory reaction in MM periprosthetic tissues.

  5. particles

    NASA Astrophysics Data System (ADS)

    Xia, Yu; Chen, Zhihong; Zhang, Zhengguo; Fang, Xiaoming; Liang, Guozheng

    2014-05-01

    We explore a facile and nontoxic hydrothermal route for synthesis of a Cu2ZnSnS4 nanocrystalline material by using l-cysteine as the sulfur source and ethylenediaminetetraacetic acid (EDTA) as the complexing agent. The effects of the amount of EDTA, the mole ratio of the three metal ions, and the hydrothermal temperature and time on the phase composition of the obtained product have been systematically investigated. The addition of EDTA and an excessive dose of ZnCl2 in the hydrothermal reaction system favor the generation of kesterite Cu2ZnSnS4. Pure kesterite Cu2ZnSnS4 has been synthesized at 180°C for 12 h from the reaction system containing 2 mmol of EDTA at 2:2:1 of Cu/Zn/Sn. It is confirmed by Raman spectroscopy that those binary and ternary phases are absent in the kesterite Cu2ZnSnS4 product. The kesterite Cu2ZnSnS4 material synthesized by the hydrothermal process consists of flower-like particles with 250 to 400 nm in size. It is revealed that the flower-like particles are assembled from single-crystal Cu2ZnSnS4 nanoflakes with ca. 20 nm in size. The band gap of the Cu2ZnSnS4 nanocrystalline material is estimated to be 1.55 eV. The films fabricated from the hierarchical Cu2ZnSnS4 particles exhibit fast photocurrent responses under intermittent visible-light irradiation, implying that they show potentials for use in solar cells and photocatalysis.

  6. Determination of neonicotinoid insecticides and strobilurin fungicides in particle phase atmospheric samples by liquid chromatography-tandem mass spectrometry.

    PubMed

    Raina-Fulton, Renata

    2015-06-01

    A liquid chromatography-tandem mass spectrometry method has been developed for the determination of neonicotinoids and strobilurin fungicides in the particle phase fraction of atmosphere samples. Filter samples were extracted with pressurized solvent extraction, followed by a cleanup step with solid phase extraction. Method detection limits for the seven neonicotinoid insecticides and six strobilurin fungicides were in the range of 1.0-4.0 pg/m(3). Samples were collected from June to September 2013 at two locations (Osoyoos and Oliver) in the southern Okanagan Valley Agricultural Region of British Columbia, where these insecticides and fungicides are recommended for use on tree fruit crops (apples, pears, cherries, peaches, apricots) and vineyards. This work represents the first detection of acetamiprid, imidacloprid, clothianidin, kresoxim-methyl, pyraclostrobin, and trifloxystrobin in particle phase atmospheric samples collected in the Okanagan Valley in Canada. The highest particle phase atmospheric concentrations were observed for imidacloprid, pyraclostrobin, and trifloxystrobin at 360.0, 655.6, and 1908.2 pg/m(3), respectively. PMID:25961332

  7. Hybrid metal organic scintillator materials system and particle detector

    DOEpatents

    Bauer, Christina A.; Allendorf, Mark D.; Doty, F. Patrick; Simmons, Blake A.

    2011-07-26

    We describe the preparation and characterization of two zinc hybrid luminescent structures based on the flexible and emissive linker molecule, trans-(4-R,4'-R') stilbene, where R and R' are mono- or poly-coordinating groups, which retain their luminescence within these solid materials. For example, reaction of trans-4,4'-stilbenedicarboxylic acid and zinc nitrate in the solvent dimethylformamide (DMF) yielded a dense 2-D network featuring zinc in both octahedral and tetrahedral coordination environments connected by trans-stilbene links. Similar reaction in diethylformamide (DEF) at higher temperatures resulted in a porous, 3-D framework structure consisting of two interpenetrating cubic lattices, each featuring basic to zinc carboxylate vertices joined by trans-stilbene, analogous to the isoreticular MOF (IRMOF) series. We demonstrate that the optical properties of both embodiments correlate directly with the local ligand environments observed in the crystal structures. We further demonstrate that these materials produce high luminescent response to proton radiation and high radiation tolerance relative to prior scintillators. These features can be used to create sophisticated scintillating detection sensors.

  8. Comprehending the activation of aerosol particles into cloud droplets: measuring strong surfactants in atmospheric aerosols and their kinetic effects

    NASA Astrophysics Data System (ADS)

    Noziere, B.; Baduel, C.

    2012-12-01

    This presentation will summarize several new developments in the field of aerosols and cloud droplet formation in the last few years. First, new chemical analysis methods were developed in our group and have evidenced the presence of very strong surfactants in a wide range of atmospheric aerosols, expected to strongly enhance the activation into cloud droplets. These analyses also reveal some variations of the surface tension of some aerosols with the season or with the presence or absence of clouds, providing new insight on the parameters controlling aerosol particle activation in the atmosphere. A summary of these results, covering a wide range of aerosols from remote and urban regions, will be presented. Comparing with field CCN measurements, it appeared that only the measurement techniques allowing for sufficient particle activation time (≧ 10 s) were able to confirm the presence of such strong surfactants. This suggested the occurrence time-dependent surface tension effects (or "kinetic" effects) in the activated particles, not well captured by these on-line techniques. Such effects were investigated in our laboratory with a range of model surfactants (Sodium dodecyl sulfate, rhamnolipids…) and the results will be presented. They show that, in some cases, strong surfactants need several ten of seconds to reach their full effect on the surface of micron-size particles. Therefore most current CCN measurement instruments are unable to capture the effect of strong surfactants in atmospheric aerosols. More importantly, these kinetics effects are representative of a wider range of molecular effects controlling the distribution of surfactants in the aqueous droplets and therefore their effect on particle activation. Although well documented in the "Colloid and Surfactant" literature, these effects are currently ignored in aerosols/CCN models resulting in erroneous calculations of the role of surfactants. Future measurements and techniques to investigate and fully understand these effects will be proposed.

  9. Anthropogenic Influence on Secondary Aerosol Formation and Total Water-Soluble Carbon on Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Gioda, Adriana; Mateus, Vinicius; Monteiro, Isabela; Taira, Fabio; Esteves, Veronica; Saint'Pierre, Tatiana

    2013-04-01

    On a global scale, the atmosphere is an important source of nutrients, as well as pollutants, because of its interfaces with soil and water. Important compounds in the gaseous phase are in both organic and inorganic forms, such as organic acids, nitrogen, sulfur and chloride. In spite of the species in gas form, a huge number of process, anthropogenic and natural, are able to form aerosols, which may be transported over long distances. Sulfates e nitrates are responsible for rain acidity; they may also increase the solubility of organic compounds and metals making them more bioavailable, and also can act as cloud condensation nuclei (CCN). Aerosol samples (PM2.5) were collected in a