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Sample records for aerosol physical characteristics

  1. Climatological Aspects of Aerosol Physical Characteristics in Tunisia Deduced from Sun Photometric Measurements

    PubMed Central

    Chaâbane, Mabrouk; Azri, Chafai; Medhioub, Khaled

    2012-01-01

    Atmospheric and climatic data measured at Thala site (Tunisia) for a long-time period (1977–2001) are used to analyse the monthly, seasonal, and annual variations of the aerosol optical depth at 1 μm wavelength. We have shown that aerosol and microphysical properties and the dominating aerosol types depend on seasons. A comparison of the seasonal cycle of aerosol optical characteristics at Thala site showed that the contribution of long-range transported particles is expected to be larger in summer as a consequence of the weather stability typical of this season. Also, the winter decrease in atmospheric turbidity may result from increases in relative humidity and decreases in temperature, leading to increased particle size and mass and increased fall and deposition velocities. The spring and autumn weather patterns usually carry fine dust and sand particles for the desert area to Thala region. The annual behaviour of the aerosol optical depth recorded a period of stead increase started in 1986 until 2001. Trends in atmospheric turbidity after 1988 could be explained other ways by the contribution of the eruption of Mount Pinatubo in 1991 and by local or regional changes in climate or in aerosol emissions. PMID:22629150

  2. Climatological aspects of aerosol physical characteristics in Tunisia deduced from sun photometric measurements.

    PubMed

    Chaâbane, Mabrouk; Azri, Chafai; Medhioub, Khaled

    2012-01-01

    Atmospheric and climatic data measured at Thala site (Tunisia) for a long-time period (1977-2001) are used to analyse the monthly, seasonal, and annual variations of the aerosol optical depth at 1 μm wavelength. We have shown that aerosol and microphysical properties and the dominating aerosol types depend on seasons. A comparison of the seasonal cycle of aerosol optical characteristics at Thala site showed that the contribution of long-range transported particles is expected to be larger in summer as a consequence of the weather stability typical of this season. Also, the winter decrease in atmospheric turbidity may result from increases in relative humidity and decreases in temperature, leading to increased particle size and mass and increased fall and deposition velocities. The spring and autumn weather patterns usually carry fine dust and sand particles for the desert area to Thala region. The annual behaviour of the aerosol optical depth recorded a period of stead increase started in 1986 until 2001. Trends in atmospheric turbidity after 1988 could be explained other ways by the contribution of the eruption of Mount Pinatubo in 1991 and by local or regional changes in climate or in aerosol emissions. PMID:22629150

  3. Aerosol Source Plume Physical Characteristics from Space-based Multiangle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.; Li, W.-H.; Moroney, Catherine; Diner, David J.; Martonchik, John V.; Fishbein, Evan

    2007-01-01

    Models that assess aerosol effects on regional air quality and global climate parameterize aerosol sources in terms of amount, type, and injection height. The multiangle imaging spectroradiometer (MISR) aboard NASA's Terra satellite retrieves total column aerosol optical thickness (AOT), and aerosol type over cloud-free land and water. A stereo-matching algorithm automatically retrieves reflecting-layer altitude wherever clouds or aerosol plumes have discernable spatial contrast, with about 500-m accuracy, at 1.1-km horizontal resolution. Near-source biomass burning smoke, volcanic effluent, and desert dust plumes are observed routinely, providing information about aerosol amount, particle type, and injection height useful for modeling applications. Compared to background aerosols, the plumes sampled have higher AOT, contain particles having expected differences in Angstrom exponent, size, single-scattering albedo, and for volcanic plume and dust cloud cases, particle shape. As basic thermodynamics predicts, thin aerosol plumes lifted only by regional winds or less intense heat sources are confined to the boundary layer. However, when sources have sufficient buoyancy, the representative plumes studied tend to concentrate within discrete, high-elevation layers of local stability; the aerosol is not uniformly distributed up to a peak altitude, as is sometimes assumed in modeling. MISR-derived plume heights, along with meteorological profile data from other sources, make it possible to relate radiant energy flux observed by the moderate resolution imaging spectroradiometer (MODIS), also aboard the Terra spacecraft, to convective heat flux that plays a major role in buoyant plume dynamics. A MISR climatology of plume behavior based on these results is being developed.

  4. Aerosols optical and physical characteristics and direct radiative forcing during a "Shamal" dust storm, a case study

    NASA Astrophysics Data System (ADS)

    Saeed, T. M.; Al-Dashti, H.; Spyrou, C.

    2013-09-01

    Dust aerosols are analyzed for their optical and physical properties during an episode of dust storm that hit Kuwait on 26 March 2003 when "Iraqi Freedom" military operation was in full swing. The intensity of the dust storm was such that it left a thick suspension of dust throughout the following day, 27 March, resulting in a considerable cooling effect at the surface on both days. Ground-based measurements of aerosol optical thickness reached 3.617 and 4.17 on 26-27 March respectively while Ångstrom coefficient, α870/440, dropped to -0.0234 and -0.0318. Particulate matter concentration of diameter 10 μm or less, PM10, peaked at 4800 μg m-3 during dust storm hours of 26 March. Moderate resolution imaging spectrometer (MODIS) retrieved optical and physical characteristics that exhibited extreme values as well. The synoptic of the dust storm is presented and source regions are identified using total ozone mapping spectrometer (TOMS) aerosol index retrieved images. The vertical profile of the dust layer was simulated using SKIRON atmospheric model. Instantaneous net direct radiative forcing is calculated at top of atmosphere (TOA) and surface level. The thick dust layer of 26 March resulted in cooling the TOA by -60 Wm-2 and surface level by -175 Wm-2 for a surface albedo of 0.35. Slightly higher values were obtained for 27 March due to the increase in aerosol optical thickness. The large reduction in the radiative flux at the surface level had caused a drop in surface temperature by approximately 6 °C below its average value. Radiative heating/cooling rates in the shortwave and longwave bands were also examined. Shortwave heating rate reached a maximum value of 2 °K day-1 between 3 and 5 km, dropped to 1.5 °K day-1 at 6 km and diminished at 8 km. Longwave radiation initially heated the lower atmosphere by a maximum value of 0.2 °K day-1 at surface level, declined sharply at increasing altitude and diminished at 4 km. Above 4 km longwave radiation started to

  5. Atmospheric aerosols: A literature summary of their physical characteristics and chemical composition

    NASA Technical Reports Server (NTRS)

    Harris, F. S., Jr.

    1976-01-01

    This report contains a summary of 199 recent references on the characterization of atmospheric aerosols with respect to their composition, sources, size distribution, and time changes, and with particular reference to the chemical elements measured by modern techniques, especially activation analysis.

  6. AEROSOL EXPOSURE, PHYSICS, AND CHEMISTRY

    EPA Science Inventory

    A brief review is given of the "Knowledge" and the "Gaps in Knowledge" of aerosol exposure, physics and chemistry relevant to health effects of aerosols, and presented or discussed in platform or poster presentations at the Symposium on Particulate Air Pollution - Associations wi...

  7. Aerosol characteristics at a rural station in southern peninsular India during CAIPEEX-IGOC: physical and chemical properties.

    PubMed

    Bisht, D S; Srivastava, A K; Pipal, A S; Srivastava, M K; Pandey, A K; Tiwari, S; Pandithurai, G

    2015-04-01

    To understand the boundary layer characteristics and pathways of aerosol-cloud interaction, an Integrated Ground Observational Campaign, concurrent with Cloud Aerosol Interaction and Precipitation Enhancement Experiment, was conducted by the Indian Institute of Tropical Meteorology, Pune, under Ministry of Earth Sciences at Mahabubnagar (a rural environment, which is ~100 km away from an urban city Hyderabad in Andhra Pradesh), during the period of July-November 2011. Collected samples of PM2.5 and PM10 were analyzed for water-soluble ionic species along with organic carbon (OC) and elemental carbon (EC). During study period, the average mass concentrations of PM2.5 and PM10 were about 50(±10) and 69(±14) μg m(-3), respectively, which are significantly higher than the prescribed Indian National Ambient Air Quality Standards values. The chemical species such as sum of anions and cations from measured chemical constituents were contributed to be 31.27 and 38.49% in PM2.5 and 6.35 and 5.65% to the PM10, whereas carbonaceous species contributed ~17.3 and 20.47% for OC and ~3.0 and 3.10% for EC, respectively. The average ratio of PM2.5/PM10 during study period was ~0.73(±0.2), indicating that the dominance of fine size particles. Carbonaceous analysis results showed that the average concentration of OC was 14 and 8.7 μg m(-3), while EC was 2.1 and 1.5 μg m(-3) for PM10 and PM2.5, respectively. The ratios between OC and EC were estimated, which were 6.6 and 5.7 for PM10 and PM2.5, suggesting the presence of secondary organic aerosol. Total carbonaceous aerosol accounts 23% of PM10 in which the contribution of OC is 20% and EC is 3%, while 20% of PM2.5 mass in which the contribution of OC is 17% and EC is 3%. Out of the total aerosols mass, water-soluble constituents contributed an average of 45% in PM10 and 38% in PM2.5 including about 39% anions and 6% cations in PM10, while 31% anions and 7% cations in PM2.5 aerosol mass collectively at study site. PMID

  8. Aerosol's optical and physical characteristics and direct radiative forcing during a shamal dust storm, a case study

    NASA Astrophysics Data System (ADS)

    Saeed, T. M.; Al-Dashti, H.; Spyrou, C.

    2014-04-01

    Dust aerosols are analyzed for their optical and physical properties during an episode of a dust storm that blew over Kuwait on 26 March 2003 when the military Operation Iraqi Freedom was in full swing. The intensity of the dust storm was such that it left a thick suspension of dust throughout the following day, 27 March. The synoptic sequence leading to the dust storm and the associated wind fields are discussed. Ground-based measurements of aerosol optical thickness reached 3.617 and 4.17 on 26 and 27 March respectively while the Ångstrom coefficient, α870/440, dropped to -0.0234 and -0.0318. Particulate matter concentration of 10 μm diameter or less, PM10, peaked at 4800 μg m-3 during dust storm hours of 26 March. Moderate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol optical depth (AOD) by Deep Blue algorithm and Total Ozone Mapping Spectrometer (TOMS) aerosol index (AI) exhibited high values. Latitude-longitude maps of AOD and AI were used to deduce source regions of dust transport over Kuwait. The vertical profile of the dust layer was simulated using the SKIRON atmospheric model. Instantaneous net direct radiative forcing is calculated at top of atmosphere (TOA) and surface level. The thick dust layer of 26 March resulted in cooling the TOA by -60 Wm-2 and surface level by -175 Wm-2 for a surface albedo of 0.35. Slightly higher values were obtained for 27 March due to the increase in aerosol optical thickness. Radiative heating/cooling rates in the shortwave and longwave bands were also examined. Shortwave heating rate reached a maximum value of 2 K day-1 between 3 and 5 km, dropped to 1.5 K day-1 at 6 km and diminished at 8 km. Longwave radiation initially heated the lower atmosphere by a maximum value of 0.2 K day-1 at surface level, declined sharply at increasing altitude and diminished at 4 km. Above 4 km longwave radiation started to cool the atmosphere slightly reaching a maximum rate of -0.1 K day-1 at 6 km.

  9. A European aerosol phenomenology - 3: Physical and chemical characteristics of particulate matter from 60 rural, urban, and kerbside sites across Europe

    NASA Astrophysics Data System (ADS)

    Putaud, J.-P.; Van Dingenen, R.; Alastuey, A.; Bauer, H.; Birmili, W.; Cyrys, J.; Flentje, H.; Fuzzi, S.; Gehrig, R.; Hansson, H. C.; Harrison, R. M.; Herrmann, H.; Hitzenberger, R.; Hüglin, C.; Jones, A. M.; Kasper-Giebl, A.; Kiss, G.; Kousa, A.; Kuhlbusch, T. A. J.; Löschau, G.; Maenhaut, W.; Molnar, A.; Moreno, T.; Pekkanen, J.; Perrino, C.; Pitz, M.; Puxbaum, H.; Querol, X.; Rodriguez, S.; Salma, I.; Schwarz, J.; Smolik, J.; Schneider, J.; Spindler, G.; ten Brink, H.; Tursic, J.; Viana, M.; Wiedensohler, A.; Raes, F.

    2010-03-01

    This paper synthesizes data on aerosol (particulate matter, PM) physical and chemical characteristics, which were obtained over the past decade in aerosol research and monitoring activities at more than 60 natural background, rural, near-city, urban, and kerbside sites across Europe. The data include simultaneously measured PM 10 and/or PM 2.5 mass on the one hand, and aerosol particle number concentrations or PM chemistry on the other hand. The aerosol data presented in our previous works ( Van Dingenen et al., 2004; Putaud et al., 2004) were updated and merged to those collected in the framework of the EU supported European Cooperation in the field of Scientific and Technical action COST633 ( Particulate matter: Properties related to health effects). A number of conclusions from our previous studies were confirmed. There is no single ratio between PM 2.5 and PM 10 mass concentrations valid for all sites, although fairly constant ratios ranging from 0.5 to 0.9 are observed at most individual sites. There is no general correlation between PM mass and particle number concentrations, although particle number concentrations increase with PM 2.5 levels at most sites. The main constituents of both PM 10 and PM 2.5 are generally organic matter, sulfate and nitrate. Mineral dust can also be a major constituent of PM 10 at kerbside sites and in Southern Europe. There is a clear decreasing gradient in SO 42- and NO 3- contribution to PM 10 when moving from rural to urban to kerbside sites. In contrast, the total carbon/PM 10 ratio increases from rural to kerbside sites. Some new conclusions were also drawn from this work: the ratio between ultrafine particle and total particle number concentration decreases with PM 2.5 concentration at all sites but one, and significant gradients in PM chemistry are observed when moving from Northwestern, to Southern to Central Europe. Compiling an even larger number of data sets would have further increased the significance of our

  10. Implementation of the Missing Aerosol Physics into LLNL IMPACT

    SciTech Connect

    Chuang, C

    2005-02-09

    characteristics and composition of aerosols. These processes, together with other physical properties (i.e., size, density, and refractive index), determine the atmospheric lifetime of aerosols and their radiative forcing. To better represent physical properties of aerosols, we adapted an aerosol microphysics model that simulates aerosol size distribution. Work toward this goal was done in collaboration with Professor Anthony Wexler of University of California at Davis. Professor Wexler's group has developed sectional models of atmospheric aerosol dynamics that include an arbitrary number of size sections and chemical compounds or compound classes. The model, AIM (Aerosol Inorganic Model), is designed to predict the mass distribution and composition of urban and regional particulate matter (''Sun and Wexler'', 1998a, b). This model is currently incorporated into EPA's Models-3 air quality modeling platform/CMAQ (Community Multiscale Air Quality) to test its performance with previous simulations of CMAQ over the continental US.

  11. Physical and Optical/Radiative Characteristics of Aerosol and Cloud Particles in Tropical Cirrus: Importance in Radiation Balance

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Howard, S. D.; Foster, T. C.; Hallett, J.; Arnott, W. P.; Condon, Estelle P. (Technical Monitor)

    1996-01-01

    Whether cirrus clouds heat or cool the Earth-atmosphere system depends on the relative importance of the cloud shortwave albedo effect and the cloud thermal greenhouse effect. Both are determined by the distribution of ice condensate with cloud particle size. The microphysics instrument package flown aboard the NASA DC-8 in TOGA/COARE included an ice crystal replicator, a 2D Greyscale Cloud Particle Probe and a Forward Scattering Spectrometer Aerosol Probe. In combination, the electro-optical instruments permitted particle size measurements between 0.5 micrometer and 2.6 millimeter diameter. Ice crystal replicas were used to validate signals from the electrooptical instruments. Both optical and scanning electron microscopy were utilized to analyze aerosol and ice particle replicas between 0.1 micrometer and several 100 micrometer diameter. In first approximation, the combined aerosol-cloud particle spectrum in several clouds followed a power law N alpha D(sup -2.5). Thus, large cloud particles carried most of the condensate mass, while small cloud and aerosol particles determined the surface area. The mechanism of formation of small particles is growth of (hygroscopic, possibly ocean-derived) aerosol particles along the Kohler curves. The concentration of small particles is higher and less variable in space and time, and their tropospheric residence time is longer, than those of large cloud particles because of lower sedimentation velocities. Small particles shift effective cloud particle radii to sizes much smaller than the mean diameter of the cloud particles. This causes an increase in shortwave reflectivity and IR emissivity, and a decrease in transmissivity. Occasionally, the cloud reflectivity increased with altitude (decreasing temperature) stronger than did cloud emissivity, yielding enhanced radiative cooling at higher altitudes. Thus, cirrus produced by deep convection in the tropics may be critical in controlling processes whereby energy from warm

  12. Aerosol physical properties from satellite horizon inversion

    NASA Technical Reports Server (NTRS)

    Gray, C. R.; Malchow, H. L.; Merritt, D. C.; Var, R. E.; Whitney, C. K.

    1973-01-01

    The feasibility is investigated of determining the physical properties of aerosols globally in the altitude region of 10 to 100 km from a satellite horizon scanning experiment. The investigation utilizes a horizon inversion technique previously developed and extended. Aerosol physical properties such as number density, size distribution, and the real and imaginary components of the index of refraction are demonstrated to be invertible in the aerosol size ranges (0.01-0.1 microns), (0.1-1.0 microns), (1.0-10 microns). Extensions of previously developed radiative transfer models and recursive inversion algorithms are displayed.

  13. The investigation of advanced remote sensing techniques for the measurement of aerosol characteristics

    NASA Technical Reports Server (NTRS)

    Deepak, A.; Becher, J.

    1979-01-01

    Advanced remote sensing techniques and inversion methods for the measurement of characteristics of aerosol and gaseous species in the atmosphere were investigated. Of particular interest were the physical and chemical properties of aerosols, such as their size distribution, number concentration, and complex refractive index, and the vertical distribution of these properties on a local as well as global scale. Remote sensing techniques for monitoring of tropospheric aerosols were developed as well as satellite monitoring of upper tropospheric and stratospheric aerosols. Computer programs were developed for solving multiple scattering and radiative transfer problems, as well as inversion/retrieval problems. A necessary aspect of these efforts was to develop models of aerosol properties.

  14. A physical model of Titan's aerosols

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Mckay, C. P.; Griffith, C. A.; Turco, R. P.

    1992-01-01

    A modeling effort is presented for the nature of the stratospheric haze on Titan, under several simplifying assumptions; chief among these is that the aerosols in question are of a single composition, and involatile. It is further assumed that a one-dimensional model is capable of simulating the general characteristics of the aerosol. It is suggested in this light that the detached haze on Titan may be a manifestation of organized, Hadley-type motions above 300 km altitude, with vertical velocities of 1 cm/sec. The hemispherical asymmetry of the visible albedo may be due to organized vertical motions within the upper 150-200 km of the haze.

  15. Physical and Chemical Properties of Anthropogenic Aerosols: An overview

    EPA Science Inventory

    A wide variety of anthropogenic sources emit fine aerosols to the atmosphere. The physical and chemical properties of these aerosols are of interest due to their influence on climate, human health, and visibility. Aerosol chemical composition is complex. Combustion aerosols can c...

  16. Characteristics of the Pinatubo Aerosol Cloud

    NASA Astrophysics Data System (ADS)

    Zhong, Weiguo

    Optical depths at visible and infrared wavelengths obtained in Tucson, Arizona before and after the Pinatubo eruption in June 1991 have been used to investigate the characteristics of the stratospheric aerosols due to the Pinatubo eruption. The intrusion of the Pinatubo aerosols over Tucson first occurred on July 26, 1991 when the spectral optical depth values rose to two to four times their normal values. In general, there was a pattern of increase between June 1991 and April 1992, and a gradual decrease after April 1992. The stratospheric Pinatubo aerosol in April 1992 was characterized by a typical columnar total number density on the order of 8.78 times 10 ^6 particles cm^{-2} in the size range of 0.2-0.7mu m. The total number density decreased to the order of 9.28 times 10^5 particles cm^{-2} by April 1994. Simulations of the size distribution using a simple polydisperse coagulation and fallout model showed that both of the processes played a very important role in the evolution and transport of the particles in the interval from April 1992 to March 1993. A strong seasonal variation was observed in the aerosol optical depth data. The values are higher in the winter and spring and lower in the summer and fall. This variation is explained by more effective transport of particles from the tropics poleward in the winter and spring than in the summer and fall. We also observed that there was a reduction in stratospheric ozone associated with the Pinatubo aerosols, possibly because of the extra sites available for heterogeneous chemical reactions. The reduction was more noticeable in the spring and summer than in other seasons. The magnitude of the ozone reduction was in a good agreement with other studies.

  17. The physical state of UTLS aerosols

    NASA Astrophysics Data System (ADS)

    Peter, Th.; Colberg, C. A.; Corti, T.; Fueglistaler, S.; Hoyle, C. R.; Koop, T.; Krieger, U. K.; Luo, B. P.; Marcolli, C.

    2003-04-01

    This paper gives an overview of the present knowledge on the physical state of aerosols in the upper troposphere (UT) and lower stratosphere (LS). Are UTLS aerosols liquid, solid or mixed-phase? And how does ice nucleate in/on such aerosols? Good progress has been made towards a quantitative theory of homogeneous nucleation of ice in purely liquid solutions of arbitrary composition and concentration based on a volume-proportional description. Very recently it has been proposed that ice nucleation might be facilitated by the surface of aerosol droplets, rather than starting in the bulk, suggests a reversal of the traditional view. Nucleation rates would then be surface-proportional rather than volume-proportional, with potentially strong effects on cloud formation, ice number densities and dehydration of UT. However, laboratory and theoretical evidence is presented corroborating the traditional picture. Above the frost point UTLS aerosols remain either liquid or mixed-phase, e.g. solid letovicite plus the remaining liquid containing aqueous inorganic acids and organic compounds. Massive deliquescence and efflorescence point reductions are expected to occur upon mixing of miscible organic and inorganic components. Hence, for a reliable prediction of the phase composition of individual aerosol particles, the knowledge of the aerosol's mixing state is indispensable. By now little is known about the morphology of mixed-phase aerosols. Experiments suggest that the solid may be coated by liquid, or conversely that the liquid might be enclosed by the solid, possibly leading to different radiative and heterogeneous chemical properties. Knowledge on the impact of efflorescence or salting out on subsequent ice formation is at its infancy. The relative importance of all these processes, in particular of homogeneous and heterogeneous ice nucleation in the UTLS, depends crucially on gravity-wave-induced small-scale temperature fluctuations with typical amplitudes of 1-2 K and

  18. Characteristics of aerosolized ice forming marine biogenic particles

    NASA Astrophysics Data System (ADS)

    Alpert, Peter A.

    Ice particles are ubiquitous in the atmosphere existing as the sole constituents of glaciated cirrus clouds or coexisting with supercooled liquid droplets in mixed-phase clouds. Aerosol particles serving as heterogeneous ice nuclei for ice crystal formation impact the global radiative balance by modification of cloud radiative properties, and thus climate. Atmospheric ice formation is not a well understood process and represents great uncertainty for climate prediction. The oceans which cover the majority of the earth's surface host nearly half the total global primary productivity and contribute to the greatest aerosol production by mass. However, the effect of biological activity on particle aerosolization, particle composition, and ice nucleation is not well established. This dissertation investigates the link between marine biological activity, aerosol particle production, physical/chemical particle characteristics, and ice nucleation under controlled laboratory conditions. Dry and humidified aerosol size distributions of particles from bursting bubbles generated by plunging water jets and aeration through frits in a seawater mesocosm containing bacteria and/or phytoplankton cultures, were measured as a function of biological activity. Total particle production significantly increases primarily due to enhanced aerosolization of particles ≤100 nm in diameter attributable to the presence and growth of phytoplankton. Furthermore, hygroscopicity measurements indicate primary organic material associated with the sea salt particles, providing additional evidence for the importance of marine biological activity for ocean derived aerosol composition. Ice nucleation experiments show that these organic rich particles nucleate ice efficiently in the immersion and deposition modes, which underscores their importance in mixed-phase and cirrus cloud formation processes. In separate ice nucleation experiments employing pure cultures of Thalassiosira pseudonana, Nannochloris

  19. Hygroscopic Characteristics of Alkylaminium Carboxylate Aerosols.

    PubMed

    Gomez-Hernandez, Mario; McKeown, Megan; Secrest, Jeremiah; Marrero-Ortiz, Wilmarie; Lavi, Avi; Rudich, Yinon; Collins, Don R; Zhang, Renyi

    2016-03-01

    The hygroscopic growth factor (HGF) and cloud condensation nuclei (CCN) activity for a series of alkylaminium carboxylate aerosols have been measured using a hygroscopicity tandem differential mobility analyzer coupled to a condensation particle counter and a CCN counter. The particles, consisting of the mixtures of mono- (acetic, propanoic, p-toluic, and cis-pinonic acid) and dicarboxylic (oxalic, succinic, malic, adipic, and azelaic acid) acid with alkylamine (mono-, di-, and trimethylamines), represent those commonly found under diverse environmental conditions. The hygroscopicity parameter (κ) of the alkylaminium carboxylate aerosols was derived from the HGF and CCN results and theoretically calculated. The HGF at 90% RH is in the range of 1.3 to 1.8 for alkylaminium monocarboxylates and 1.1 to 2.2 for alkylaminium dicarboxylates, dependent on the molecular functionality (i.e., the carboxylic or OH functional group in organic acids and methyl substitution in alkylamines). The κ value for all alkylaminium carboxylates is in the range of 0.06-1.37 derived from the HGF measurements at 90% RH, 0.05-0.49 derived from the CCN measurements, and 0.22-0.66 theoretically calculated. The measured hygroscopicity of the alkylaminium carboxylates increases with decreasing acid to base ratio. The deliquescence point is apparent for several of the alkylaminium dicarboxylates but not for the alkylaminium monocarboxylates. Our results reveal that alkylaminium carboxylate aerosols exhibit distinct hygroscopic and deliquescent characteristics that are dependent on their molecular functionality, hence regulating their impacts on human health, air quality, and direct and indirect radiative forcing on climate. PMID:26794419

  20. Biological availability of lead in a paint aerosol. 1. Physical and chemical characterization of a lead paint aerosol.

    PubMed

    Kalman, D; Schumacher, R; Covert, D; Eaton, D L

    1984-09-01

    This study was conducted to determine the physical and chemical characteristics of an aerosol of lead-based paint, generated in an industrial spray operation, that might influence the biological availability of lead present in inhaled aerosols. Paint aerosols were collected, and mass-size distribution was determined using a portable cascade impactor under actual occupational conditions. Approx. 2% of the particulate mass collected was in the respirable range (less than 10 micron mean aerodynamic diameter), although the maximum airborne concentration of lead was found to be 2-3 mg/m3. The lead concentration in a dried aerosol was very resistant to chemical digestion. Analysis by X-ray diffraction, atomic absorption spectroscopy and inductively coupled plasma emission spectroscopy showed approx. 11% lead by dry weight, although the wet weight concentration of lead reported by the manufacturer was 12.8%. PMID:6485003

  1. Paint spray tests for respirators: aerosol characteristics.

    PubMed

    Ackley, M W

    1980-05-01

    Liquid paint is sprayed from an atomizing nozzle to form an aerosol for testing paint spray respirators. The generated aerosol conditions are dependent upon liguid properties, spray-nozzle flow conditions and droplet evaporation. A technique was developed for controlling the aerosol concentrations reliably. Particle-size distributions of lacquer and enamel have been measured. The lacquer distribution was found to be multi-modal. Aerosol concentration dradients arise when the nozzle is not properly positioned. Filter loading resistance is significantly affected by these concentration variations. With regard to selection of standard aerosol test be improved by modifying the current NIOSH criteria to include a description of the particle-size distribution, a more precise definition of the paint and paint thinner chemical compositions, and a narrower concentration range. PMID:6932174

  2. Aerosol physical properties in the stratosphere (APPS) radiometer design

    NASA Technical Reports Server (NTRS)

    Gray, C. R.; Woodin, E. A.; Anderson, T. J.; Magee, R. J.; Karthas, G. W.

    1977-01-01

    The measurement concepts and radiometer design developed to obtain earth-limb spectral radiance measurements for the Aerosol Physical Properties in the Stratosphere (APPS) measurement program are presented. The measurements made by a radiometer of this design can be inverted to yield vertical profiles of Rayleigh scatterers, ozone, nitrogen dioxide, aerosol extinction, and aerosol physical properties, including a Junge size-distribution parameter, and a real and imaginary index of refraction. The radiometer design provides the capacity for remote sensing of stratospheric constituents from space on platforms such as the space shuttle and satellites, and therefore provides for global measurements on a daily basis.

  3. Aerosol Chemical and Physical Characterization in Central Amazonia during the 2013 Dry Season

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Stern, R.; Brito, J.; Carbone, S.

    2015-12-01

    During the dry season, the central Amazon forest is highly influenced by forest fires transported through large distances, changing drastically the atmospheric composition even in remote places. This work focuses on a physical-chemical characterization of the aerosol population over a pristine site in Central Amazonia during the dry season. The submicrometer organic aerosols were measured with the Aerodyne ACSM (Aerosol Chemical Speciation Monitor, Aerodyne Inc). Optical properties, size distribution and other micro-physical characteristics were also analyzed. Other instruments were simultaneously used. The measurements were taken during the dry season of 2013 in the Cuieiras ecological reserve (ZF2), northwest of Manaus. The statistical analysis of the data was done with the PMF (Positive Matrix Factorization) technique, in which the organic aerosol was separated into different factors, and then its sources and forming processes were attributed. Results show that the mean aerosol loading was 5,91 μg m-3, from which 78% are of organic composition, 8.5% are sulfate, 6.5% are equivalent black carbon, 4% are ammonium and 3% are nitrate. The mass spectra variability can be explained by 3 factors only, determined with the PMF technique. They were identified as BBOA (Biomass Burning Organic Aerosol), representing 12% of the total organic mass, OOA (Oxygenated Organic Aerosol), representing 66% of the total organic mass and IEPOX-SOA (Isoprene derived Epoxydiol-Secondary Organic Aerosol), representing 21% of the total organic mass. Even in remote and pristine regions, Central Amazonia is highly impacted by biomass burning. Biogenic secondary organic aerosols are also present during the dry season, and the suppression of its wet deposition processes increases their concentration. The oxidation level and other physical-chemical characteristics indicate that the long range transport is responsible for the regional range of this impact.

  4. Physical properties of the stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Toon, O. B.; Pollack, J. B.

    1973-01-01

    A comparison of the equilibrium vapor pressure over nitric acid solutions with observed water and nitric acid partial pressures in the stratosphere implies that nitric acid cannot be present as an aerosol particle in the lower stratosphere. A similar comparison for sulfuric acid solutions indicates that sulfuric acid aerosol particles are 75% H2SO4 by weight in water, in good agreement with direct observations. The freezing curve of H2SO4 solutions requires that the H2SO4 aerosol particles be solid or supercooled. The equilibrium vapor pressure of H2SO4 in the stratosphere is of the order of 20 picotorr. At stratospheric temperatures, ammonium sulfate is in a ferroelectric phase. As a result, polar molecules may form a surface coating on these aerosols, which may be a fertile ground for further chemical reaction.

  5. Analysis of the Impact of Major Dust Events on the Aerosols Characteristics over Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Farahat, Ashraf; El-Askary, Hesham; Al-Shaibani, Abdulaziz; Hariri, Mustafa M.

    2015-04-01

    The Kingdom of Saudi Arabia is a major source of atmospheric dust. Frequent dust storms blow up and significantly affect human activities, airports and citizens' health. Aerosols optical and physical characteristics are influenced by major dust storms outbreaks. In this, paper, ground based AERONET measurements are integrated with space-borne sensors, namely MODIS and CALIPSO to analyze aerosols' characteristics during March - May of 2009 where a massive dust storm blew up and caused a widespread heavy atmospheric dust load over Saudi Arabia and the same period during 2010, where less dust activities were reported. The MODIS Deep Blue AOD analysis showed similar aerosols pattern over the land, however a substantial variance in aerosol loading during March - May 2009 compared with the same period in 2010 was observed. The angstrom exponent analysis showed that the majority of aerosol measurements in 2009 and 2010 are dominated by coarse-mode particles with angstrom exponent < 0.5. Detailed analysis of aerosol optical properties shows significant influence of coarse mode particles in the enhanced aerosol loading in 2009. The volume depolarization rations (VDR) derived from CALIPSO backscattering measurements is used to find latitudinal profile of mean aerosol optical depth to indicate the type of particles and to discriminate spherical aerosols with non-spherical particles. Acknowledgement The authors would like to acknowledge the support provided by the King Abdel Aziz City for Science & Technology (KACST) for funding this work under grant No. (MT-32-76). The support provided by the Deanship of Research at King Fahd University of Petroleum & Minerals (KFUPM) is gratefully acknowledged.

  6. Quantitative determination of stratospheric aerosol characteristics

    NASA Technical Reports Server (NTRS)

    Tingey, D. L.; Potter, J. (Principal Investigator)

    1975-01-01

    The author has identified the following significant results. In the S192 data, a peak was apparent in the lower altitudes that was not present in the shorter wavelengths and grew with increasing wavelength beginning with band 7. For ten S192 wavelengths, the relative altitude increment was determined by knowledge of the relative position of the highest point in the scan arc. Using this scheme, results of scaling and inverting data for passes 47 and 61 were put into two models. Each result had three chart representations: (1) limb brightness measurement, (2) attenuation coefficients, and (3) ratio of the aerosol and Rayleigh coefficients to accentuate layers.

  7. Aerosol characteristics of different types of episode.

    PubMed

    Kuo, Chung-Yih; Lin, Yan-Ruei; Chang, Shih-Yu; Lin, Chuan-Yao; Chou, Chun-Hung

    2013-12-01

    Daily and hourly average data from nine air-quality monitoring stations distributed across central Taiwan, which include ten items (i.e., PM₁₀, PM₂.₅, wind direction, wind speed, temperature, relative humidity, SO₂, NO₂, NO, and CO), were collected from 2005 to 2009. Four episode types: long-range transport with dust storms (DS), long-range transport with frontal pollution (FP), river dust (RD), and stagnant weather (SW), and one mixed type of episode were identified. Of these four episode types, the SW was the dominant type, averaging about 70%. The mean ratio of PM₂.₅/PM₁₀ was the lowest during the RD episodes (0.42), while the mean ratio of PM₂.₅/PM₁₀ was the highest during the SW episodes (0.64). Fine aerosol (PM₂.₅) and coarse aerosol (PM₁₀-₂.₅) samples were collected by high-volume samplers for chemical composition analysis, from only three stations (Douliou, Lunbei, and Siansi) during the days of SW, RD, DS, and FP. The concentrations of PM₂.₅ and three ionic species (NH₄⁺, NO₃⁻, and SO₄²⁻) all showed significant differences among the four episode types. The highest levels of NO₃⁻ (12.1 μg/m(3)) and SO₄²⁻ (20.5 μg/m(3)) were found during the SW and FP episodes, respectively. A comparison on the spatial similarity of aerosol compositions among the episodes and/or non-episodes (control) was characterized by the coefficient of divergence (CD). The results showed higher CD values in PM₁₀-₂.₅ than in PM₂.₅, and the CD values between RD episodes and the other three episodes were higher than those between two types of episode for the other three episodes. The ratios of SOR (sulfur oxidation ratio), SO₄²⁻/EC (elemental carbon), NOR (nitrogen oxidation ratio), and NO₃⁻/EC showed that sulfate formation was most rapid during the FP, while nitrate formation was most rapid during the SW. PMID:23761164

  8. Characteristics of biological aerosols in dairy processing plants.

    PubMed

    Kang, Y J; Frank, J F

    1990-03-01

    The viable aerosol in dairy processing plant environments was characterized by using an Andersen six-stage sieve sampler and a Reuter centrifugal sampler. Artificially introduced Serratia marcescens were detected in the air during drain flooding and after rinsing the floor with a pressured water hose, thus illustrating the ability of a specific microorganism to be disseminated from drains and wet surfaces via physical disruption activities often observed in food plants. Once a high concentration of wet viable aerosol was generated, it took 40 or more min to return to the background level in the absence of forced ventilation or other activity. The greatest reduction in viable particles occurred during the first 10 min. Estimated mean aerosol particle sizes were decreased from approximately 4.6 to 3.2 mu with time lapse. The estimated mean aerosol particle sizes from actual dairy processing plant environments ranged from approximately 4.3 to 5.3 mu. In addition, a more heavily contaminated dairy processing environment contained larger aerosol particles. These results indicate that the RCS sampler will often overestimate the true aerosol concentration in highly contaminated air, because mean particle sizes are over 4 mu in diameter. PMID:2187913

  9. Physical and Chemical Characterization of Carbonaceous Aerosols in Korea

    NASA Astrophysics Data System (ADS)

    Choung, S.; Jin, J. S.; Hwang, G. S.; Jang, K. S.; Han, W. S.; OH, J.; Kwon, Y.

    2014-12-01

    Atmospheric aerosols have been recently paid attention more in environmental research due to their negative effects on air quality, public health, and climate change. The aerosols contain approximately >20-50% carbonaceous components such as organic carbon (OC) and black carbon (BC) (or elemental carbon [EC]) derived from organic compounds, biomass burning, and incomplete combustion of fossil fuels. The physical, chemical, and biological properties of atmospheric aerosols are strongly dependent on the carbonaceous components. In particular, the BC could significantly affect the regional air quality in the northeastern Asia, because China is one of the foremost BC emission country in the world. Previous studies have mainly focused on the quantification and source identification for carbonaceous aerosols. However, understanding of physical and chemical properties for the carbonaceous aerosols related to environmental contamination and toxicity was still incomplete due to analytical difficulties. This study is addressed to evaluate the contribution of carbonaceous aerosols to air pollution through the surface, mass spectroscopic, and electron microscopic analyses, and determination of chemical composition and structure using the air particulate matter (PM2.5 and >PM2.5) samples.

  10. Analyses of scattering characteristics of chosen anthropogenic aerosols

    NASA Astrophysics Data System (ADS)

    Kaszczuk, Miroslawa; Mierczyk, Zygmunt; Muzal, Michal

    2008-10-01

    In the work, analyses of scattering profile of chosen anthropogenic aerosols for two wavelengths (λ1 = 1064 nm and λ2 = 532 nm) were made. As an example of anthropogenic aerosol three different pyrotechnic mixtures (DM11, M2, M16) were taken. Main parameters of smoke particles were firstly analyzed and well described, taking particle shape and size into special consideration. Shape of particles was analyzed on the basis of SEM pictures, and particle size was measured. Participation of particles in each fixed fraction characterized by range of sizes was analyzed and parameters of smoke particles of characteristic sizes and function describing aerosol size distribution (ASD) were determinated. Analyses of scattering profiles were carried out on the basis of both model of scattering on spherical and nonspherical particles. In the case of spherical particles Rayleigh-Mie model was used and for nonspherical particles analyses firstly model of spheroids was used, and then Rayleigh-Mie one. For each characteristic particle one calculated value of four parameters (effective scattering cross section σSCA, effective backscattering cross section σBSCA, scattering efficiency QSCA, backscattering efficiency QBSCA) and value of backscattering coefficient β for whole particles population. Obtained results were compared with the same parameters calculated for natural aerosol (cirrus cloud).

  11. A physical model of Titan's aerosols.

    PubMed

    Toon, O B; McKay, C P; Griffith, C A; Turco, R P

    1992-01-01

    Microphysical simulations of Titan's stratospheric haze show that aerosol microphysics is linked to organized dynamical processes. The detached haze layer may be a manifestation of 1 cm sec-1 vertical velocities at altitudes above 300 km. The hemispherical asymmetry in the visible albedo may be caused by 0.05 cm sec-1 vertical velocities at altitudes of 150 to 200 km, we predict contrast reversal beyond 0.6 micrometer. Tomasko and Smith's (1982, Icarus 51, 65-95) model, in which a layer of large particles above 220 km altitude is responsible for the high forward scattering observed by Rages and Pollack (1983, Icarus 55, 50-62), is a natural outcome of the detached haze layer being produced by rising motions if aerosol mass production occurs primarily below the detached haze layer. The aerosol's electrical charge is critical for the particle size and optical depth of the haze. The geometric albedo, particularly in the ultraviolet and near infrared, requires that the particle size be near 0.15 micrometer down to altitudes below 100 km, which is consistent with polarization observations (Tomasko and Smith 1982, West and Smith 1991, Icarus 90, 330-333). Above about 400 km and below about 150 km Yung et al.'s (1984, Astrophys. J. Suppl. Ser. 55, 465-506) diffusion coefficients are too small. Dynamical processes control the haze particles below about 150 km. The relatively large eddy diffusion coefficients in the lower stratosphere result in a vertically extensive region with nonuniform mixing ratios of condensable gases, so that most hydrocarbons may condense very near the tropopause rather than tens of kilometers above it. The optical depths of hydrocarbon clouds are probably less than one, requiring that abundant gases such as ethane condense on a subset of the haze particles to create relatively large, rapidly removed particles. The wavelength dependence of the optical radius is calculated for use in analyzing observations of the geometric albedo. The lower

  12. An Aerosol Physical Chemistry Model for the Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Lin, Jin-Sheng

    2001-01-01

    This report is the final report for the Cooperative Agreement NCC2-1000. The tasks outlined in the various proposals are listed with a brief comment as to the research performed. The publications titles are: The effects of particle size and nitric acid uptake on the homogenous freezing of sulfate aerosols; Parameterization of an aerosol physical chemistry model (APCM) for the NH3/H2SO4/HNO3/H2O system at cold temperatures; and The onset, extent and duration of dehydration in the Southern Hemisphere polar vortex.

  13. Aerosols physical properties at Hada Al Sham, western Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Lihavainen, H.; Alghamdi, M. A.; Hyvärinen, A.-P.; Hussein, T.; Aaltonen, V.; Abdelmaksoud, A. S.; Al-Jeelani, H.; Almazroui, M.; Almehmadi, F. M.; Al Zawad, F. M.; Hakala, J.; Khoder, M.; Neitola, K.; Petäjä, T.; Shabbaj, I. I.; Hämeri, K.

    2016-06-01

    This is the first time to clearly derive the comprehensive physical properties of aerosols at a rural background area in Saudi Arabia. Aerosol measurements station was established at a rural background area in the Western Saudi Arabia to study the aerosol properties. This study gives overview of the aerosol physical properties (PM10, PM2.5, black carbon and total number concentration) over the measurement period from November 2012 to February 2015. The average PM10 and PM2.5 concentrations were 95 ± 78 μg m-3 (mean ± STD, at ambient conditions) and 33 ± 68 μg m-3 (at ambient conditions), respectively. As expected PM10 concentration was dominated by coarse mode particles (PM10-PM2.5), most probably desert dust. Especially from February to June the coarse mode concentrations were high because of dust storm season. Aerosol mass concentrations had clear diurnal cycle. Lower values were observed around noon. This behavior is caused by wind direction and speed, during night time very calm easterly winds are dominating whereas during daytime the stronger westerly winds are dominating (sea breeze). During the day time the boundary layer is evolving, causing enhanced mixing and dilution leading to lower concentration. PM10 and PM2.5 concentrations were comparable to values measured at close by city of Jeddah. Black carbon concentration was about 2% and 6% of PM10 and PM2.5 mass, respectively. Total number concentration was dominated by frequent new particle formation and particle growth events. The typical diurnal cycle in particle total number concentration was clearly different from PM10 and PM2.5.

  14. Physical characteristics of Chinese Hakka.

    PubMed

    Zheng, Lianbin; Li, Yonglan; Lu, Shunhua; Bao, Jinping; Wang, Yang; Zhang, Xiaorui; Xue, Hong; Rong, Wenguo

    2013-06-01

    Using standard and internationally validated methods, 86 anthropologic characteristics were determined in 650 male (305 from urban areas and 345 from rural areas) and 704 female (331 from urban areas, 373 from rural areas) Chinese Hakka adults living in Guangdong and Jiangxi. The data were used to calculate 24 anthropologic indices, which were analyzed statistically. The physical characteristics of Hakka subjects were analyzed and compared with reference ethnic data. There were four main findings of this study. First, a small proportion of Hakka adults had an eye fold on the upper eyelid, but a large proportion had a mongoloid fold. The eye slits were narrow in most adults, had a medium nasal root height and straight bridges, and most of the external angles were prominent. The nasal base was upturned in most men. The distributions of the three types of nasal base in women were similar. The proportions of subjects with middle and high alae nasi heights were high and similar. Males with a maximum nostril diameter were mostly classified as transverse and oblique, while many women were classified as transverse and had relatively wide alae nasi. The round lobe type was the most common. Upper lip skin height was mostly classified as medium. Lips were classified as thin. The hair was black, eyes were brown, and the skin was yellowish. Second, the head length was long in male Hakka. The minimum frontal breadth, face breadth, lip height, and interocular breadth were similar to those of North-Asian populations. Meanwhile, head breadth, morphological facial height, nose breadth, mouth breadth, and nose height were similar to those of South-Asian populations. Head length was long in female Hakka. The minimum frontal breadth, face breadth, lip height, and interocular breadth were similar to those of North-Asian populations. Head breadth, nose breadth, and mouth breadth were similar to those of South-Asian populations. Third, the stature of male and female Hakka in urban and

  15. Effects of formulation and operating variables on zanamivir dry powder inhalation characteristics and aerosolization performance.

    PubMed

    Yang, Yang; Yang, Ziwei; Ren, Yufeng; Mei, Xingguo

    2014-09-01

    Abstract The objective of this study was to investigate the influence of formulation and operating variables on the physical characteristics and aerosolization performance of zanamivir spary-dried powders for inhalation. Spray-dried samples of zanamivir, zanamivir/mannitol and zanamivir/mannitol/leucine were prepared from their corresponding aqueous solutions under the same conditions to study the influence of the composition, and zanamivir/mannitol/leucine (1/1/3 by weight) formulation was used for investigation of the effect of the preparation process. Dry powders were characterized afterwards for different physical properties, including morphology, particle size, flowability, density and moisture absorption. The in vitro deposition was also evaluated after the aerosolization of powders at 100 L min(-1) via the Aerolizer® into a Next Generation Impactor (NGI). The highest FPF of 41.40 ± 1.1% was obtained with a zanamivir/mannitol/leucine ratio of 1/1/3, which had an average Dg of 3.11 ± 0.13 μm and an angle of repose of 36°( )± 1. It was found that the influence of the preparation process on zanamivir spary-dried powders characteristics and aerosolization properties was relatively small, but the influence of the composition was relatively large. Optimization of DPI can be achieved by selecting the most appropriate formulation and preparation process. PMID:24491208

  16. Aerosol optical and physical properties during winter monsoon pollution transport in an urban environment.

    PubMed

    Verma, S; Bhanja, S N; Pani, S K; Misra, A

    2014-04-01

    We analysed aerosol optical and physical properties in an urban environment (Kolkata) during winter monsoon pollution transport from nearby and far-off regions. Prevailing meteorological conditions, viz. low temperature and wind speed, and a strong downdraft of air mass, indicated weak dispersion and inhibition of vertical mixing of aerosols. Spectral features of WinMon aerosol optical depth (AOD) showed larger variability (0.68-1.13) in monthly mean AOD at short-wavelength (SW) channels (0.34-0.5 μm) compared to that (0.28-0.37) at long-wavelength (LW) channels (0.87-1.02 μm), thereby indicating sensitivity of WinMon AOD to fine aerosol constituents and the predominant contribution from fine aerosol constituents to WinMon AOD. WinMon AOD at 0.5 μm (AOD 0. 5) and Angstrom parameter ( α) were 0.68-0.82 and 1.14-1.32, respectively, with their highest value in December. Consistent with inference from spectral features of AOD, surface aerosol loading was primarily constituted of fine aerosols (size 0.23-3 μm) which was 60-70 % of aerosol 10- μm (size 0.23-10 μm) concentration. Three distinct modes of aerosol distribution were obtained, with the highest WinMon concentration at a mass median diameter (MMD) of 0.3 μm during December, thereby indicating characteristics of primary contribution related to anthropogenic pollutants that were inferred to be mostly due to contribution from air mass originating in nearby region having predominant emissions from biofuel and fossil fuel combustion. A relatively higher contribution from aerosols in the upper atmospheric layers than at the surface to WinMon AOD was inferred during February compared to other months and was attributed to predominant contribution from open burning emissions arising from nearby and far-off regions. A comparison of ground-based measurements with Moderate Resolution Imaging Spectroradiometer (MODIS) data showed an underestimation of MODIS AOD and α values for most of the days. Discrepancy in

  17. A study of the performance of different acidic aerosol samplers and the characteristics of acidic aerosols in Hsinchu Taiwan

    SciTech Connect

    Tsai, C.J.; Perng, S.B.; Chiou, S.F.; Lin, T.Y.

    1999-07-01

    An annular denuder system (ADS), a honeycomb denuder system (HDS) and a micro-orifice uniform deposit impactor (MOUDI) were used to investigate the physical and chemical characteristics of acidic aerosols in Hsinchu Taiwan. The performances of different denuder samplers were also compared. The concentrations (in {mu}g/m{sup 3}) of major ionic species: H{sup +}, SO{sub 4}{sup 2{minus}} NO{sub 3}{sup {minus}} and NH{sub 4}{sup +} are found to average 0.019{+-}0.01 (std. dev.) (range: 0.00--0.02), 7.60{+-}5.08 (range: 1.37--16.54), 7.67{+-}5.50 (range: 1.18--21.58) and 5.27{+-}2.90 (range: 1.14--9.42), as measured by the ADS, respectively. Aerosol acidity is not severe compared to urban cities in other countries, due to neutralization of aerosol acidity by ammonia in Hsinchu. The results indicate that the size distributions of H{sup +} and NH{sub 4}{sup +} are in the single mode while those of NO{sub 3}{sup {minus}} and SO{sub 4}{sup 2{minus}} are found to be mainly bimodal. The ions such as SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +} and H{sup +} are dominant in the fine mode, while ions such as Cl{sup {minus}}, Na{sup +} and K{sup +} are found to be in both fine and coarse modes. Comparing two different denuder samplers, the average concentration of HNO{sub 3} measured by the HDS is found to be 40% higher than that of the ADS while the average concentrations of NO{sub 3}{sup {minus}} and Cl{sup {minus}} measured by the ADS are higher than those of the HDS by 12% and 14%, respectively. The concentrations of other species are found to be similar in both denuder samplers.

  18. Physical and Chemical Properties of Anthropogenic Aerosols: An Overview

    EPA Science Inventory

    Aerosol chemical composition is complex. Combustion aerosols can comprise tens of thousands of organic compounds, refractory brown and black carbon, heavy metals, cations, anions, salts, and other inorganic phases. Aerosol organic matter normally contains semivolatile material th...

  19. The characteristics of brown carbon aerosol during winter in Beijing

    NASA Astrophysics Data System (ADS)

    Cheng, Yuan; He, Ke-bin; Du, Zhen-yu; Engling, Guenter; Liu, Jiu-meng; Ma, Yong-liang; Zheng, Mei; Weber, Rodney J.

    2016-02-01

    Brown carbon (i.e., light-absorbing organic carbon, or BrC) exerts important effects on the environment and on climate in particular. Based on spectrophotometric absorption measurements on extracts of bulk aerosol samples, this study investigated the characteristics of BrC during winter in Beijing, China. Organic compounds extractable by methanol contributed approximately 85% to the organic carbon (OC) mass. Light absorption by the methanol extracts exhibited a strong wavelength dependence, with an average absorption Ångström exponent of 7.10 (fitted between 310 and 450 nm). Normalizing the absorption coefficient (babs) measured at 365 nm to the extractable OC mass yielded an average mass absorption efficiency (MAE) of 1.45 m2/g for the methanol extracts. This study suggests that light absorption by BrC could be comparable with black carbon in the spectral range of near-ultraviolet light. Our results also indicate that BrC absorption and thus BrC radiative forcing could be largely underestimated when using water-soluble organic carbon (WSOC) as a surrogate for BrC. Compared to previous work relying only on WSOC, this study provides a more comprehensive understanding of BrC aerosol based on methanol extraction.

  20. Lidar Measurements of the Vertical Distribution of Aerosol Optical and Physical Properties over Central Asia

    DOE PAGESBeta

    Chen, Boris B.; Sverdlik, Leonid G.; Imashev, Sanjar A.; Solomon, Paul A.; Lantz, Jeffrey; Schauer, James J.; Shafer, Martin M.; Artamonova, Maria S.; Carmichael, Gregory R.

    2013-01-01

    The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM 2.5 and PM 10 mass and chemical composition in both size fractions. Dust transported into the region is common, being detected 33% of the time. The maximum frequency occurred in the spring of 2009. Dust transported to Central Asia comes from regional sources, for example, Taklimakan desert and Aral Sea basin, and from long-range transport, for example, deserts of Arabia, Northeast Africa, Iran, and Pakistan. Regionalmore » sources are characterized by pollution transport with maximum values of coarse particles within the planetary boundary layer, aerosol optical thickness, extinction coefficient, integral coefficient of aerosol backscatter, and minimum values of the Ångström exponent. Pollution associated with air masses transported over long distances has different characteristics during autumn, winter, and spring. During winter, dust emissions were low resulting in high values of the Ångström exponent (about 0.51) and the fine particle mass fraction (64%). Dust storms were more frequent during spring with an increase in coarse dust particles in comparison to winter. The aerosol vertical profiles can be used to lower uncertainty in estimating radiative forcing.« less

  1. Statistical characteristics of atmospheric aerosol as determined from AERONET measurements

    NASA Astrophysics Data System (ADS)

    Yoon, Jongmin; Kokhanovsky, Alexander

    2015-04-01

    Seasonal means and standard deviations of column-integrated aerosol optical properties (e.g. spectral aerosol optical thickness (AOT), single scattering albedo, phase function, Ångström exponent, volume particle size distribution, complex refractive index, absorbing aerosol optical thickness) from several Aerosol Robotic Network (AERONET) sites located in typical aerosol source and background regions are investigated (Holben et al., 1998). The AERONET program is an inclusive network of ground-based sun-photometers that measure atmospheric aerosol optical properties (http://aeronet.gsfc.nasa.gov/). The results can be used for improving the accuracy of satellite-retrieved AOT, assessments of the global aerosol models, studies of atmospheric pollution and aerosol radiative forcing on climate. We have paid a special attention to several AERONET sites that are Mexico_City (Mexico), Alta_Floresta (Brazil), Avignon (France), Solar_Village (Saudi Arabia), and Midway_Island (Pacific) representative for industrial/urban, biomass burning, rural, desert dust and oceanic aerosols, respectively. We have found that the optical and microphysical aerosol properties are highly dependent on the local aerosol emission sources and seasonal meteorological conditions.

  2. Reverse aqueous microemulsions in hydrofluoroalkane propellants and their aerosol characteristics.

    PubMed

    Selvam, Parthiban; Bharatwaj, Balaji; Porcar, Lionel; da Rocha, Sandro R P

    2012-01-17

    In this work we describe the structure and environment of reverse aqueous microemulsions formed in 1,1,1,2-tetrafluoroethane (HFA134a) propellant in the presence of a non-ionic ethoxylated copolymer, and the aerosol characteristics of the corresponding pressurized metered dose inhaler (pMDI) formulations. The activity of selected polypropylene oxide-polyethylene oxide-polypropylene oxide (PO(m)EO(n)PO(m)) amphiphiles at the HFA134a-water interface was studied using in situ high-pressure tensiometry, and those results were used as a guide in the selection of the most appropriate candidate surfactant for the formation of microemulsions in the compressed HFA134a. The environment and structure of the aggregates formed with the selected surfactant candidate, PO(22)EO(14)PO(22), was probed via UV-vis spectroscopy (molecular probe), and small angle neutron scattering (SANS), respectively. High water loading capacity in the core of the nanoaggregates was achieved in the presence of ethanol. At a water-to-surfactant molar ratio of 21 and 10% ethanol, cylindrical aggregates with a radius of 18Å, and length of 254Å were confirmed with SANS. Anderson Cascade Impactor (ACI) results reveal that the concentration of the excipients (C(exp), including surfactant, water and ethanol) has a strong effect on the aerosol characteristics of the formulations, including the respirable fraction, and the mass mean aerodynamic diameter (MMAD), and that the trend in MMAD can be predicted as a function of the C(exp) following similar correlations to those proposed to common non-volatile excipients, indicating that the nanodroplets of water dispersed in the propellant behave similarly to molecularly solubilized compounds. Cytotoxicity studies of PO(22)EO(14)PO(22) were performed in A549 cells, an alveolar type II epithelial cell line, and indicate that, within the concentration range of interest, the surfactant in question decreases cell viability only lightly. The relevance of this work

  3. Characteristics of atmospheric aerosol optical depth variation in China during 1993-2012

    NASA Astrophysics Data System (ADS)

    Xu, X.; Qiu, J.; Xia, X.; Sun, L.; Min, M.

    2014-12-01

    Atmospheric aerosol optical depth (AOD) is a critical physical parameter for indicating atmospheric turbidity and aerosol content, and is also a key factor in determining the aerosol radiative forcing effects. This study gives the long-term variation characteristics of atmospheric aerosol optical depth at 14 first-class solar radiation stations in China during 1993-2012. Based on the broadband extinction method (BEM), we retrieve the AOD from the hourly accumulated direct solar radiation. Using a AOD selection method, we derive and analyze the monthly, seasonal and annual averaged AOD. The results show that (1) the mean AOD ranges from 0.135 (Lhasa) to 0.678 (Zhengzhou). Shenyang has the maximum standard deviation of 0.109, while Ejin Banner has the minimum value of 0.021. The mean value for all years and stations is 0.423. (2) At most stations, the largest AOD appears in spring and the smallest in autumn. The seasonal averaged AOD of all years and stations is 0.487 (spring), 0.456 (summer), 0.364 (autumn) and 0.381 (winter). (3) As to the variation trend, an increasing trend appeared at five stations (Kashi, Kunming, Zhengzhou, Wuhan and Shanghai), while a decreasing trend is found at two stations (Guangzhou and Beijing). After analyzing the correlations between AOD and the meteorological factors (i.e. temperature, pressure, humidity and visibility), we find that AOD has a positive correlation with temperature, and a negative correlation with pressure and visibility at most of the stations.

  4. Characteristics of regional aerosols: Southern Arizona and eastern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Prabhakar, Gouri

    Atmospheric aerosols impact the quality of our life in many direct and indirect ways. Inhalation of aerosols can have harmful effects on human health. Aerosols also have climatic impacts by absorbing or scattering solar radiation, or more indirectly through their interactions with clouds. Despite a better understanding of several relevant aerosol properties and processes in the past years, they remain the largest uncertainty in the estimate of global radiative forcing. The uncertainties arise because although aerosols are ubiquitous in the Earth's atmosphere they are highly variable in space, time and their physicochemical properties. This makes in-situ measurements of aerosols vital in our effort towards reducing uncertainties in the estimate of global radiative forcing due to aerosols. This study is an effort to characterize atmospheric aerosols at a regional scale, in southern Arizona and eastern Pacific Ocean, based on ground and airborne observations of aerosols. Metals and metalloids in particles with aerodynamic diameter (Dp) smaller than 2.5 μm are found to be ubiquitous in southern Arizona. The major sources of the elements considered in the study are identified to be crustal dust, smelting/mining activities and fuel combustion. The spatial and temporal variability in the mass concentrations of these elements depend both on the source strength and meteorological conditions. Aircraft measurements of aerosol and cloud properties collected during various field campaigns over the eastern Pacific Ocean are used to study the sources of nitrate in stratocumulus cloud water and the relevant processes. The major sources of nitrate in cloud water in the region are emissions from ships and wildfires. Different pathways for nitrate to enter cloud water and the role of meteorology in these processes are examined. Observations of microphysical properties of ambient aerosols in ship plumes are examined. The study shows that there is an enhancement in the number

  5. A Physically-Based Estimate of Radiative Forcing by Anthropogenic Sulfate Aerosol

    SciTech Connect

    Ghan, Steven J.); Easter, Richard C.); Chapman, Elaine G.); Abdul-Razzak, Hayder; Zhang, Yang ); Leung, Ruby ); Laulainen, Nels S.); Saylor, Rick D.); Zaveri, Rahul A.)

    2001-04-01

    Estimates of direct and indirect radiative forcing by anthropogenic sulfate aerosols from an integrated global aerosol and climate modeling system are presented. A detailed global tropospheric chemistry and aerosol model that predicts concentrations of oxidants as well as aerosols and aerosol precursors, is coupled to a general circulation model that predicts both cloud water mass and cloud droplet number. Both number and mass of several externally-mixed aerosol size modes are predicted, with internal mixing assumed for the different aerosol components within each mode. Predicted aerosol species include sulfate, organic and black carbon, soil dust, and sea salt. The models use physically-based treatments of aerosol radiative properties (including dependence on relative humidity) and aerosol activation as cloud condensation nuclei. Parallel simulations with and without anthropogenic sulfate aerosol are performed for a global domain. The global and annual mean direct and indirect radiative forcing due to anthropogenic sulfate are estimated to be -0.3 to -0.5 and -1.5 to -3.0 W m-2, respectively. The radiative forcing is sensitive to the model's horizontal resolution, the use of predicted vs. analyzed relative humidity, the prediction vs. diagnosis of aerosol number and droplet number, and the parameterization of droplet collision/coalescence. About half of the indirect radiative forcing is due to changes in droplet radius and half to increased cloud liquid water.

  6. Aerosol size distribution seasonal characteristics measured in Tiksi, Russian Arctic

    NASA Astrophysics Data System (ADS)

    Asmi, E.; Kondratyev, V.; Brus, D.; Laurila, T.; Lihavainen, H.; Backman, J.; Vakkari, V.; Aurela, M.; Hatakka, J.; Viisanen, Y.; Uttal, T.; Ivakhov, V.; Makshtas, A.

    2015-07-01

    Four years of continuous aerosol number size distribution measurements from an Arctic Climate Observatory in Tiksi Russia are analyzed. Source region effects on particle modal features, and number and mass concentrations are presented for different seasons. The monthly median total aerosol number concentration in Tiksi ranges from 184 cm-3 in November to 724 cm-3 in July with a local maximum in March of 481 cm-3. The total mass concentration has a distinct maximum in February-March of 1.72-2.38 μg m-3 and two minimums in June of 0.42 μg m-3 and in September-October of 0.36-0.57 μg m-3. These seasonal cycles in number and mass concentrations are related to isolated aerosol sources such as Arctic haze in early spring which increases accumulation and coarse mode numbers, and biogenic emissions in summer which affects the smaller, nucleation and Aitken mode particles. The impact of temperature dependent natural emissions on aerosol and cloud condensation nuclei numbers was significant. Therefore, in addition to the precursor emissions of biogenic volatile organic compounds, the frequent Siberian forest fires, although far are suggested to play a role in Arctic aerosol composition during the warmest months. During calm and cold months aerosol concentrations were occasionally increased by nearby aerosol sources in trapping inversions. These results provide valuable information on inter-annual cycles and sources of Arctic aerosols.

  7. Trace elemental characteristics of aerosols emitted from municipal incinerators

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1978-01-01

    As part of a continuing investigation of high temperature combustion aerosols, elemental composition of size differentiated aerosols emitted from a local municipal incinerator was studied. Aerosols were aerodynamically separated into eight diameter groups ranging from 0.43 mm to 20 mm, collected, and analyzed by charged particle induced X-ray emission technique. On line data collection and reduction codes generated aerial densities for elements from Na to U with sensitivities in the ng/cu m range for most elements. From the total weights of aerosols collected per stage, their size distribution was determined to be bimodal, with one group centered at a diameter of 0.54 mm and the other at a diameter of 5.6 mm. Measured elemental concentrations in various size ranges indicate that K and S show a strong tendency to concentrate on aerosol surfaces. A weaker trend for surface preference was also observed for Mn and Ni, but other elements show no such trend.

  8. Complex measurements of aerosol and ion characteristics in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Kikas, Iu. E.; Kolomiets, S. M.; Kornienko, V. I.; Mirme, A. A.; Sal'm, Ia. I.; Sergeev, I. Ia.; Tammet, Kh. F.

    Results of a comprehensive study of the characteristics of atmospheric ions and aerosols in the boundary layer during the summer season are reported. A study is also made of the kinetics of aerosol formation under conditions of high artificial ionization of the air by alpha and UV radiation. A high degree of correlation is shown to exist between atmospheric concentrations of medium ions and fine (less than 0.01 micron) aerosol. The results obtained support the radiation-chemical mechanism of aerosol formation.

  9. Characterization of marine boundary layer aerosol from North Atlantic and European sources: Physical and chemical properties and climate forcing parameters

    NASA Astrophysics Data System (ADS)

    Dusek, Ulrike

    This thesis focuses on aerosol properties measured in Southwestern Portugal during the second Aerosol Characterization Experiment. Fundamental aerosol physical properties such as particle size distribution and hygroscopic properties are related to possible sources and aerosol transformation processes. From these fundamental properties we derive aerosol properties that are important for aerosol forcing of climate. First, a new method for calculating CCN spectra is proposed in this work and tested using sensitivity studies and comparisons to direct measurements. The measured and calculated CCN spectra differ on average by 30%, which at small supersaturations is similar to the measurement uncertainties. Second, aerosol number to volume ratios (R) are calculated and the fact that values of R are relatively constrained is explained based on observed correlations between size distribution parameters. Third, a simple parameterization of the humidity dependence of the submicron aerosol scattering coefficient has been derived, depending only on a volume weighted average diameter growth factor and the volume mean diameter of the dry size distribution. One set of empirical parameters can be used to parameterize all aerosol types characterized during the ACE-2 measurement period. Aerosol physical properties and climate forcing parameters in the North-East Atlantic Ocean were clearly affected by pollution outbreaks from Europe. The submicron particle volume increased by a factor of 5 in polluted conditions, the light scattering coefficient of dry particles increased on average by a factor of up to 10, CCN concentrations at supersaturations of 0.2% increased by a factor of 3--5. The aerosol fundamental properties vary often strongly with air mass history, but also show short-term variability that often has a characteristic diurnal scale. The number concentration of fine particles below 50nm and the particle hygroscopic growth factors are mostly dominated by diurnal processes

  10. Climatology and Characteristics of Aerosol Optical Properties in the Arctic

    NASA Astrophysics Data System (ADS)

    Schmeisser, Lauren; Ogren, John; Backman, John; Asmi, Eija; Andrews, Elisabeth; Jefferson, Anne; Bergin, Michael; Tunved, Peter; Sharma, Sangeeta; Starkweather, Sandra

    2016-04-01

    Within the Arctic, climate forcers like atmospheric aerosols are important contributors to the observed warming and environmental changes in the region. Quantifying the forcing by aerosols in the Arctic is especially difficult, given short aerosol lifetimes, annual variability in illumination and surface albedo, stratified atmospheric conditions, complex feedbacks, and long-range aerosol transport. However, in-situ surface measurements of Arctic aerosol optical properties can be used to constrain variability of light scattering and absorption, identify potential particle sources, and help evaluate the resulting forcing. Data from six WMO Global Atmosphere Watch stations are presented: Alert, Canada (ALT); Barrow, Alaska (BRW); Pallas, Finland (PAL); Summit, Greenland (SUM); Tiksi, Russia (TIK); and Zeppelin Mountain, Norway (ZEP). These sites contribute to the International Arctic System for Observing the Atmosphere (IASOA), which facilitates Arctic-wide data collection and analysis. Climatologies of aerosol optical properties from each station show differences in magnitude and variability of observed parameters. For example, most stations (ALT, BRW, SUM, TIK, ZEP) experience maximum scattering in winter/spring, while PAL exhibits maximum scattering in the summer. The observed range in scattering across these sites is large (almost an order of magnitude) - SUM has the lowest annual median scattering at 0.82 Mm-1 while BRW has the highest at 6.9 Mm-1. A closer look at systematic variability between optical properties at each station, as well as site back trajectories, suggest differences in aerosol processes, sources and transport. The development of consistent climatologies and additional analyses like the ones presented here can help provide a better understanding of trans-Arctic aerosol variability, which can be an asset for improving aerosol models in this unique and remote region.

  11. Measurements of aerosol physical properties at a high altitude station in central Himalayas during RAWEX-GVAX

    NASA Astrophysics Data System (ADS)

    Pant, Vimlesh; Sagar, Ram; Pant, P.; Krishna Moorthy, K.; Venkata Phanikumar, Devulapalli; Dumka, Umesh Chandra; Singh, Narendra; Sahai, Shivraj; Kotamarthi, V. R.; Satheesh, S. K.; Naja, Manish

    2012-07-01

    Physical properties of atmospheric aerosols are being measured at a high altitude site Manora Peak, Nainital (29.4°N, 79.5°E; 1950 m amsl) in central Himalaya under the Regional Aerosols Warming Experiment-Ganges Valley Aerosol Experiment (RAWEX-GVAX). The cloud condensation nuclei counter (single-column DMT Model 1) and condensation particle counter (TSI Model 3010) are operated round the clock since June 2011 during the first ARM Mobile Facility (AMF1) deployment. The preliminary analyses of data obtained from these instruments together with the meteorological observations during June-September, 2011 are reported here. Number concentrations of condensation nuclei (N _{CN}) and cloud condensation nuclei (N _{CCN}) show characteristic features of atmospheric aerosols in the Indo-Gangetic Plain (IGP) region in the northern India. Concentrations of N _{CCN} are measured at seven supersaturations between -0.01% to 0.75% in steps. The nominal concentration of N _{CN}, particularly during low wind speeds, was in the range of 500 -- 2000 cm ^{-3}. The concentrations of N _{CCN} are observed to increase with the increasing supersaturations. In most of the cases, the variations in both N _{CN} and N _{CCN} are similar. Rapid decrease in aerosol number concentrations was observed after the precipitation associated with southwest monsoon. The effects of regional sources as well as the long-range transport on the aerosol physical properties in the IGP region are studied. Further analysis of data expected to reveal crucial role of aerosols in cloud microphysical processes and regional climate over this region.

  12. Chemical, physical, and optical evolution of biomass burning aerosols: a case study

    NASA Astrophysics Data System (ADS)

    Adler, G.; Flores, J. M.; Abo Riziq, A.; Borrmann, S.; Rudich, Y.

    2010-10-01

    In-situ chemical composition measurements of ambient aerosols have been used for characterizing the evolution of submicron aerosols from a large anthropogenic biomass burning (BB) event in Israel. A high resolution Time of Flight Aerosol Mass Spectrometer (Hi-RES-TOF-AMS) was used to follow the chemical evolution of BB aerosols during a night-long, extensive nationwide wood burning event and during the following day. While extensive BB is not common in this region, burning of agricultural waste is a common practice. The aging process of the BB aerosols was followed through their chemical, physical and optical properties. Mass spectrometric analysis of the aerosol organic component showed that aerosol aging is characterized by shifting from less oxidized fresh BB aerosols to more oxidized aerosols. Evidence for aerosol aging during the day following the BB event was indicated by an increase in the organic mass, its oxidation state, the total aerosol concentration, and a shift in the modal particle diameter. The effective broadband refractive index (EBRI) was derived using a white light optical particle counter (WELAS). The average EBRI for a mixed population of aerosols dominated by open fires was m=1.53(±0.03)+0.07i(±0.03), during the smoldering phase of the fires we found the EBRI to be m=1.54(±0.01)+0.04i(±0.01) compared to m=1.49(±0.01)+0.02i(±0.01) of the aged aerosols during the following day. This change indicates a decrease in the overall aerosol absorption and scattering. Elevated levels of particulate Polycyclic Aromatic Hydrocarbons (PAHs) were detected during the entire event, which suggest possible implications for human health during such extensive event.

  13. Chemical, physical, and optical evolution of biomass burning aerosols: a case study

    NASA Astrophysics Data System (ADS)

    Adler, G.; Flores, J. M.; Abo Riziq, A.; Borrmann, S.; Rudich, Y.

    2011-02-01

    In-situ chemical composition measurements of ambient aerosols have been used for characterizing the evolution of submicron aerosols from a large anthropogenic biomass burning (BB) event in Israel. A high resolution Time of Flight Aerosol Mass Spectrometer (HR-RES-TOF-AMS) was used to follow the chemical evolution of BB aerosols during a night-long, extensive nationwide wood burning event and during the following day. While these types of extensive BB events are not common in this region, burning of agricultural waste is a common practice. The aging process of the BB aerosols was followed through their chemical, physical and optical properties. Mass spectrometric analysis of the aerosol organic component showed that aerosol aging is characterized by shifting from less oxidized fresh BB aerosols to more oxidized aerosols. Evidence for aerosol aging during the day following the BB event was indicated by an increase in the organic mass, its oxidation state, the total aerosol concentration, and a shift in the modal particle diameter. The effective broadband refractive index (EBRI) was derived using a white light optical particle counter (WELAS). The average EBRI for a mixed population of aerosols dominated by open fires was m = 1.53(±0.03) + 0.07i(±0.03), during the smoldering phase of the fires we found the EBRI to be m = 1.54(±0.01) + 0.04i(±0.01) compared to m = 1.49(±0.01) + 0.02i(±0.01) of the aged aerosols during the following day. This change indicates a decrease in the overall aerosol absorption and scattering. Elevated levels of particulate Polycyclic Aromatic Hydrocarbons (PAHs) were detected during the entire event, which suggest possible implications for human health during such extensive event.

  14. Physical characteristics related to bra fit.

    PubMed

    Chen, Chin-Man; LaBat, Karen; Bye, Elizabeth

    2010-04-01

    Producing well-fitting garments has been a challenge for retailers and manufacturers since mass production began. Poorly fitted bras can cause discomfort or pain and result in lost sales for retailers. Because body contours are important factors affecting bra fit, this study analyses the relationship of physical characteristics to bra-fit problems. This study has used 3-D body-scanning technology to extract upper body angles from a sample of 103 college women; these data were used to categorise physical characteristics into shoulder slope, bust prominence, back curvature and acromion placement. Relationships between these physical categories and bra-fit problems were then analysed. Results show that significant main effects and two-way interactions of the physical categories exist in the fit problems of poor bra support and bra-motion restriction. The findings are valuable in helping the apparel industry create better-fitting bras. STATEMENT OF RELEVANCE: Poorly fitted bras can cause discomfort or pain and result in lost sales for retailers. The findings regarding body-shape classification provide researchers with a statistics method to quantify physical characteristics and the findings regarding the relationship analysis between physical characteristics and bra fit offer bra companies valuable information about bra-fit perceptions attributable to women with figure variations. PMID:20309747

  15. Towards climatological study on the characteristics of aerosols in Central Africa and Mediterranean sites

    NASA Astrophysics Data System (ADS)

    Benkhalifa, Jamel; Chaabane, Mabrouk

    2016-02-01

    The atmosphere contains molecules, clouds and aerosols that are sub-millimeter particles having a large variability in size, shape, chemical composition, lifetime and contents. The aerosols concentration depends greatly on the geographical situation, meteorological and environmental conditions, which makes aerosol climatology difficult to assess. Setting up a solar photometer (automatic, autonomous and portable instrument) on a given site allows carrying out the necessary measurements for aerosol characterization. The particle microphysical and optical properties are obtained from photometric measurements. The objective of this study is to analyze the spatial variability of aerosol optical thickness (AOT) in several Mediterranean regions and Central Africa, we considered a set of simultaneous data in the AErosol RObotic NETwork (AERONET) from six sites, two of which are located in Central Africa (Banizoumbou and Zinder Airport) and the rest are Mediterranean sites (Barcelona, Malaga, Lampedusa, and Forth Crete). The results have shown that the physical properties of aerosols are closely linked to the climate nature of the studied site. The optical thickness, single scattering albedo and aerosols size distribution can be due to the aging of the dust aerosol as they are transported over the Mediterranean basin.

  16. An analysis of the characteristics of aerosol light scattering coefficients at Seoul and Baengnyeongdo

    NASA Astrophysics Data System (ADS)

    Kim, B.; Eun, S.; Seo, W.; Park, J.; Ahn, J.; Moon, K.

    2013-12-01

    Aerosols in the atmosphere can scatter and absorb solar radiation and their spatial/temporal distributions are highly inhomogeneous due to short lifetimes (about a few weeks or less). Through scattering and absorption of solar radiation, aerosols directly affect visibility and climate through the modification of the Earth's energy budget (Charlson et al., 1992; Yan, 2007; Wang, 2012). This study investigates long-term trends and characteristics of aerosol light scattering coefficient at Seoul and Baengnyeongdo, 100 km upstream of Seoul, in Korea. Aerosol scattering coefficients were measured continuously with nephelometers. The analysis period is limited to one year of 2011. For the relationship analysis of extinction coefficients (σext) to visibility and aerosol optical depth, σsp observed at 3 p.m. have been used with help of aerosol absorption coefficients (σap) in order to remove its dependence upon relative humidity (RH), and also those of rainy period have been excluded. As expected, σext estimated are inversely proportional to visibility observation by eye. Aerosol extinction coefficients have been vertically integrated with an assumption of nearly well-mixed within an e-folding height to determine aerosol optical depth (τa), and compared with those retrieved from sunphotometer. The results show a reasonable agreement in spite of an inherent difference of each definition. We expect these findings would help to eventually understand aerosol radiative forcing and its effect on the regional climate change around Korea.

  17. Characteristics of the General Physics student population.

    NASA Astrophysics Data System (ADS)

    Hunt, Gary L.

    2006-12-01

    Are pre-medical students different than the other students in a General physics class? They often appear to be different, based on how often they seek help from the instructor or how nervous they are about 2 points on a lab report. But are these students different in a measurable characteristic? The purpose of this study is to better understand the characteristics of the students in the introductory physics classes. This is the first step toward improving the instruction. By better understanding the students the classroom, the organization and pedagogy can be adjusted to optimize student learning. The characteristics to be investigated during this study are: · student epistemological structure, · student attitudes, · science course preparation prior to this course, · study techniques used, · physics concepts gained during the class · performance in the class. The data will be analyzed to investigate differences between groups. The groups investigated will be major, gender, and traditional/nontraditional students.

  18. Physical and Chemical Characterization of Particles in the Upper Troposphere and Lower Stratosphere: Microanalysis of Aerosol Impactor Samples

    NASA Technical Reports Server (NTRS)

    Sheridan, Patrick J.

    1999-01-01

    according to the major fraction. Thus, many of the particles classified as sulfate may have contained significant mass fractions of carbonaceous or other material. These particles for the most part did not show two physical phases, however. Nonsulfate particles were classified according to the physical and chemical characteristics of each particle, and were grouped into the major nonsulfate particle classes, including C-rich, crustal, metallic, and salts. Our UT and LS sample analyses indicate a maximum for crustal and C-rich particle abundance in the Northern Hemisphere upper troposphere, and a salt particle maximum in the Southern Hemisphere upper troposphere. Metallic particles are clearly more prevalent in the troposphere than in the stratosphere, but interhemispheric differences appear small.

  19. Optical Characteristics of Aerosols and Clouds Retrieved from Sky Radiometer Data of SKYNET

    NASA Astrophysics Data System (ADS)

    Khatri, P.; Irie, H.; Takamura, T.

    2015-12-01

    SKYNET is an observation network to collect data related to aerosols, clouds, and radiation using a variety of ground-based instruments. The sky radiometer, manufactured by PREDE Co. Ltd., Japan, is one of the SKYNET instruments. Present research activities have made it possible to retrieve not only optical characteristics of aerosols and clouds, but also columnar water vapor and ozone concentrations using data of this instrument. This study analyzes sky radiometer data of various sites to understand optical characteristics of aerosols of different backgrounds. Several interesting results were obtained. For example, the light-absorption capacity of dust aerosols was observed to depend on not only mixed pollutants but also on aerosol size. We further studied the effects of aerosols on atmospheric heat budget using such observation data and a radiative transfer model. The results showed clear spatial and temporal variations of aerosol radiative forcing at the surface as well as top of atmosphere (TOA). Sky radiometer data of selected super sites of SKYNET were also analyzed to understand the optical characteristics of clouds. Such retrieved cloud parameters were validated using irradiances measured at the surface as well as MODIS cloud parameters. Though differences exist with respect to MODIS cloud parameters, irradiances calculated using sky radiometer retrieved cloud parameters agree fairly well with observed values.

  20. Comparison of aerosol properties over Beijing and Kanpur: Optical, physical properties and aerosol component composition retrieved from 12 years ground-based Sun-sky radiometer remote sensing data

    NASA Astrophysics Data System (ADS)

    Li, Zhengqiang; Li, Lei; Zhang, Fengxia; Li, Donghui; Xie, Yisong; Xu, Hua

    2015-02-01

    Aerosol mixtures composed of coarse and fine particles occur frequently in metropolitan areas in the world, especially in developing countries. Beijing, China, and Kanpur, India, are both in Asian monsoon regions and experience strong aerosol loading because of increased economic activities, vehicles, and urbanization. Observations originating from the Aerosol Robotic Network (AERONET) have played a vital role in the field of aerosol study. In order to understand the variations of aerosol optical, physical properties and component composition over Beijing and Kanpur, we focus on AERONET measurements collected at these two sites from 2002 to 2013 and employ a five-component (including black carbon, BC; mineral dust, DU; brown carbon, BrC; ammonium sulfate like, AS; and aerosol water content, AW) aerosol mixture model to retrieve the aerosol component composition. Particle size distribution, spectral characteristics of single-scattering albedo, and refractive indices of the aerosols over Beijing and Kanpur are found to be distinct and with regular seasonal variations. Correspondingly, aerosol components show distinct temporal characteristics at both sites. In Beijing, BC shows a significant decrease from 2002 to 2013 (especially after 2007) with an average declining rate of 0.69 mg m-2 yr-1. Among the five components, BC and BrC are higher during winter and autumn especially at Beijing, while DU and AS are higher during spring and summer at the two sites. With respect to site differences, BC and BrC are usually higher in Beijing in most of the year, while DU and AS are higher in Kanpur especially from April to June. Moreover, AW is similar and quite comparable at two sites.

  1. Chemical, physical, and optical evolution of biomass burning aerosols: A case study

    NASA Astrophysics Data System (ADS)

    Adler, G.; Flores, M.; Borrmann, S.; Rudich, Y.

    2010-12-01

    In-situ chemical composition measurements of ambient aerosols have been used for characterizing the evolution of submicron aerosols of a large anthropogenic biomass burning (BB) event in Israel. A high resolution Time of Flight Aerosol Mass Spectrometer (Hi-RES-TOF-AMS) was used to follow the chemical evolution of BB aerosols during a night-long, extensive nationwide wood burning event and during the following day. While extensive BB is not common in this region, burning of agricultural waste is a common practice. The aging process of the BB aerosols was followed through their chemical, physical and optical properties. Mass spectrometric analysis of the aerosol organic component showed that aerosol aging is characterized by shifting from less oxidized fresh BB aerosols to more oxidized aerosols. Evidence for aerosol aging during the day following the BB event was indicated by an increase in the organic mass, its oxidation state, the total aerosol concentration, and a shift in the modal particle diameter. The effective broadband refractive index (EBRI) was derived using a white light optical particle counter (WELAS). EBRI during the smoldering phase of the fires was m=1.54(±0.01)+0.04i(±0.01) compared to m=1.49(±0.01)+0.02i(±0.01) of the aged aerosols during the following day. This change indicates a decrease in the overall aerosol absorption and scattering. Elevated levels of particulate Polycyclic Aromatic Hydrocarbons (PAHs) were detected during the entire event, which suggest possible implications for human health during such extensive event.

  2. Aerosol size distribution seasonal characteristics measured in Tiksi, Russian Arctic

    NASA Astrophysics Data System (ADS)

    Asmi, E.; Kondratyev, V.; Brus, D.; Laurila, T.; Lihavainen, H.; Backman, J.; Vakkari, V.; Aurela, M.; Hatakka, J.; Viisanen, Y.; Uttal, T.; Ivakhov, V.; Makshtas, A.

    2016-02-01

    Four years of continuous aerosol number size distribution measurements from the Arctic Climate Observatory in Tiksi, Russia, are analyzed. Tiksi is located in a region where in situ information on aerosol particle properties has not been previously available. Particle size distributions were measured with a differential mobility particle sizer (in the diameter range of 7-500 nm) and with an aerodynamic particle sizer (in the diameter range of 0.5-10 μm). Source region effects on particle modal features and number, and mass concentrations are presented for different seasons. The monthly median total aerosol number concentration in Tiksi ranges from 184 cm-3 in November to 724 cm-3 in July, with a local maximum in March of 481 cm-3. The total mass concentration has a distinct maximum in February-March of 1.72-2.38 μg m-3 and two minimums in June (0.42 μg m-3) and in September-October (0.36-0.57 μg m-3). These seasonal cycles in number and mass concentrations are related to isolated processes and phenomena such as Arctic haze in early spring, which increases accumulation and coarse-mode numbers, and secondary particle formation in spring and summer, which affects the nucleation and Aitken mode particle concentrations. Secondary particle formation was frequently observed in Tiksi and was shown to be slightly more common in marine, in comparison to continental, air flows. Particle formation rates were the highest in spring, while the particle growth rates peaked in summer. These results suggest two different origins for secondary particles, anthropogenic pollution being the important source in spring and biogenic emissions being significant in summer. The impact of temperature-dependent natural emissions on aerosol and cloud condensation nuclei numbers was significant: the increase in both the particle mass and the CCN (cloud condensation nuclei) number with temperature was found to be higher than in any previous study done over the boreal forest region. In addition

  3. Predicting Adult Personality from Minor Physical Characteristics.

    ERIC Educational Resources Information Center

    Paulhus, Delroy; Martin, Carol

    While minor physical anomalies (MPAs), a set of 17 non-obvious but measurable characteristics of the hands, face and feet, have been linked to a number of behavioral syndromes in children, such personality correlates of MPAs in adults have not been studied. To explore the relationshp between MPAs and temperament in a college sample, 114 students…

  4. New biometric modalities using internal physical characteristics

    NASA Astrophysics Data System (ADS)

    Mortenson, Juliana (Brooks)

    2010-04-01

    Biometrics is described as the science of identifying people based on physical characteristics such as their fingerprints, facial features, hand geometry, iris patterns, palm prints, or speech recognition. Notably, all of these physical characteristics are visible or detectable from the exterior of the body. These external characteristics can be lifted, photographed, copied or recorded for unauthorized access to a biometric system. Individual humans are unique internally, however, just as they are unique externally. New biometric modalities have been developed which identify people based on their unique internal characteristics. For example, "BoneprintsTM" use acoustic fields to scan the unique bone density pattern of a thumb pressed on a small acoustic sensor. Thanks to advances in piezoelectric materials the acoustic sensor can be placed in virtually any device such as a steering wheel, door handle, or keyboard. Similarly, "Imp-PrintsTM" measure the electrical impedance patterns of a hand to identify or verify a person's identity. Small impedance sensors can be easily embedded in devices such as smart cards, handles, or wall mounts. These internal biometric modalities rely on physical characteristics which are not visible or photographable, providing an added level of security. In addition, both the acoustic and impedance methods can be combined with physiologic measurements such as acoustic Doppler or impedance plethysmography, respectively. Added verification that the biometric pattern came from a living person can be obtained. These new biometric modalities have the potential to allay user concerns over protection of privacy, while providing a higher level of security.*

  5. An Aerosol Physical Chemistry Model for the Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Lin, Jin-Sheng

    2001-01-01

    This report is the final report for the Cooperative Agreement NCC2-1000. The tasks outlined in the various proposals are: (1) Development of an aerosol chemistry model; (2) Utilization of satellite measurements of trace gases along with analysis of temperatures and dynamic conditions to understand ice cloud formation, dehydration and sedimentation in the winter polar regions; (3) Comparison of the HALOE and SAGE II time dependencies of the Pinatubo aerosol decay. The publications are attached.

  6. Aerosol characteristics from the Taiwan aerosol supersite in the Asian yellow-dust periods of 2002

    NASA Astrophysics Data System (ADS)

    Lee, Chung-Te; Chuang, Ming-Tung; Chan, Chang-Chuan; Cheng, Tsun-Jen; Huang, Song-Lih

    The occurrence of Asian dust storms, and the subsequent transport of yellow dust (YD) greatly influences the air quality of lee-side countries such as Korea and Japan. The dust is also frequently transported in a southward direction by a strong cold high-pressure system that affects the air quality in Taiwan. This study reports the aerosol properties that were monitored continuously at the Taiwan aerosol supersite during YD events in 2002. Based on the observations of meteorology and aerosols, we divided the time interval of a YD event into a before period, during period, and after period. Among the seven observed YD events, the second event was marked with the maximum hourly PM 10 level at 502 μg m -3, and with the longest during period for a total of 147 h. The averages of the hourly PM 10 and PM 2.5-10 were much higher in the during period as compared to those in the before period. It is interesting to note that the time lapse in the during period was well correlated with the maximum level of both PM 10 and PM 2.5-10. It must be noted that the PM 2.5 levels were dramatically increased in the after period, which was due to the accumulation of particles influenced by the anticyclonic outflow. The aerosol size distribution in the third YD event verified that supermicron particles dominated in the during period, and that submicron particles were predominant in the before and after periods. For the chemical properties of the aerosols, time series results indicated that sulfates were mostly contributed by the dust transport, and the others were more related to vehicle exhausts. However, they all accumulated in the period of atmospheric stagnancy.

  7. Speciated local aerosol characteristics and radiative forcing at a rural midwestern site

    NASA Astrophysics Data System (ADS)

    Dillner, Ann Marie

    2000-11-01

    In this research, physical and chemical properties of ambient aerosols were measured at a rural perturbed mid- latitude site (Bondville, IL) and used to calculate the aerosol optical properties and the resulting direct radiative forcing. Size-segregated aerosol samples were collected during the summer of 1997 using three parallel MOUDIs operating at ambient relative humidity. Two sample sets were used to obtain sulfate, organic carbon (OC), elemental carbon (EC), carbonate and total aerosol mass. The third sample set was used to obtain the size-specific and wavelength-dependent extinction efficiency of EC. The measured submicrometer mass concentration was 11.4 +/- 4.0 μg m-3. Ammonium sulfate comprised nearly half of the submicrometer aerosol and OC plus EC comprised 25%. Water content for ammonium sulfate and OC was estimated using both Köhler theory and parameterized water uptake curves from the literature. Water content for internally mixed aerosols was determined using a ZSR method. Aerosol optical properties (extinction efficiency, asymmetry parameter, single scatter albedo) were calculated from measured size distributions and wavelength dependent refractive indexes for each species and for internal and external mixtures using Mie theory. A technique, utilizing transmission measurements through extracts of size segregated ambient aerosol samples, was developed to obtain the extinction efficiency of EC. Measured EC extinction efficiencies ranged from 7.3 to 1.7 m2 g-1 at 550 nm, depending on particle diameter. Normalized direct aerosol radiative forcing (W g-1 ) was calculated using the Column Radiation Module (CRM) of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM3). Aerosol optical properties, used in the model, were assumed to be uniform throughout the lowest one kilometer of the atmosphere. The normalized forcing due to ammonium sulfate was -340 +/- 10 W g-1. OC was 1/3 larger and residue was 1/3 smaller. EC within an

  8. Investigation of aerosol characteristics from the central Himalayas and its adjacent foothills

    NASA Astrophysics Data System (ADS)

    Joshi, Hema; Naja, Manish; Babu, Suresh; Satheesh, Sk; Pal Singh, Krishna; Kumar, Rajesh; Moorthy, KKrishna

    2016-04-01

    Studies on atmospheric aerosols are important in the South Asia, especially over the Himalayas owing to their crucial role in regional climate change, radiation budget etc. The present study provides some of the crucial insights into the understanding of aerosol characteristics and associated processes over the central Himalayan region. The long term ground based aerosol data from high altitude site, Nainital (29.4°N, 79.5°E, 1958 m), India, are utilized extensively and estimated trends of the aerosol optical depth (AOD) and black carbon (BC) shows the increasing trend over this region. The significant amount of aerosol abundance is also observed in spring season each year. Further, in order to understand the transport and influence of aerosols from the Indo-Gangetic Plain (IGP) region to the nearby Himalayas, aerosols observation initiated from the low altitude site Pantnagar (29.0°N, 79.5°E, 231 m), India, are also utilized. Observations at these both sites which are merely at a distance of ~30 km show marked differences in the levels and seasonal and diurnal variations. The Himalayan site, is marked with low AOD and BC, except in spring, while IGP site is marked with high level of aerosols throughout the year. BC is maximum in winter (7.9±5.2 μg m-3) and minimum in summer-monsoon in IGP which exhibits nearly an inverse relation with mixing layer depth which is strongest in winter. On the other hand, BC reaches maximum in spring at Nainital. AOD is high throughout the year in IGP which shows annual peak (AOD500nm>0.6) in May-June, dominated by coarse mode, while fine mode aerosols dominates in late autumn and early winter. The Nainital site is marked with very low AOD in winter typical to clean site. Seasonal mean BC is found to be significantly higher at Pantnagar in winter (~652%), followed by in autumn (~577%), summer-monsoon (~318%) and spring (~248%) as compared to those at Nainital. Co-located observation of AOD along with aerosols extinction

  9. Chemical characteristics of aerosol mists in phosphate fertilizer manufacturing facilities.

    PubMed

    Hsu, Yu-Mei; Wu, Chang-Yu; Lundgren, Dale A; Nall, J Wesley; Birky, Brian K

    2007-01-01

    Of the carcinogens listed by the National Toxicology Program (NTP), strong inorganic mists containing sulfuric acid were identified as a known human carcinogen. In this study, aerosol sampling was conducted at 24 locations in eight Florida phosphoric acid and concentrated fertilizer manufacturing plants and two locations as background in Winter Haven and Gainesville, Florida, using dichotomous samplers. The locations were selected where sulfuric acid mist may potentially exist, including sulfuric acid pump tank areas, belt or rotating table phosphoric acid filter floors, sulfuric acid truck loading/unloading stations, phosphoric acid production reactors (attack tanks), and a concentrated fertilizer granulator during scrubbing with a weak sulfuric acid mixture. An ion chromatography system was used to analyze sulfate and other water soluble ion species. In general, sulfate, fluoride, ammonium, and phosphate were the major species in the fertilizer facilities. For the rotating table/belt phosphoric acid filter floor, phosphate and fluoride were the dominant species for PM10, and the maximum concentrations were 170 and 106 microg/m3, respectively. For the attack tank, fluoride was the dominant species for PM10, and the maximum concentration was 462 microg/m3. At the sulfuric acid pump tank, sulfate was the dominant species, and the maximum PM10 sulfate concentration was 181 microg/m3. The concentration of PM10 sulfate including ammonium sulfate, calcium sulfate, and sulfuric acid were lower than 0.2 mg/m3 at all locations. The aerosols at the filter floor and the attack tank were acidic. The coarse mode aerosol at the sulfuric acid pump tank (an outdoor location) was acidic, whereas the fine mode aerosol was neutral to basic. PMID:17162477

  10. Physical characteristics of Eurasian winter temperature variability

    NASA Astrophysics Data System (ADS)

    Kim, Kwang-Yul; Son, Seok-Woo

    2016-04-01

    Despite the on-going global warming, recent winters in Eurasian mid-latitudes were much colder than average. In an attempt to better understand the physical characteristics for cold Eurasian winters, major sources of variability in surface air temperature (SAT) are investigated based on cyclostationary EOF analysis. The two leading modes of SAT variability represent the effect of Arctic amplification (AA) and the Arctic oscillation (AO), respectively. These two modes are distinct in terms of the physical characteristics, including surface energy fluxes and tropospheric circulations, and result in significantly different winter SAT patterns over the Eurasian continent. The AA-related SAT anomalies are dipolar with warm Arctic, centered at the Barents–Kara Seas, and cold East Asia. In contrast, the negative AO-related SAT anomalies are characterized by widespread cold anomalies in Northern Eurasia. Relative importance of the AA and the negative AO contributions to cold Eurasian winters is sensitive to the region of interest.

  11. The NASA-AMES Research Center Stratospheric Aerosol Model. 1. Physical Processes and Computational Analogs

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Hamill, P.; Toon, O. B.; Whitten, R. C.; Kiang, C. S.

    1979-01-01

    A time-dependent one-dimensional model of the stratospheric sulfate aerosol layer is presented. In constructing the model, a wide range of basic physical and chemical processes are incorporated in order to avoid predetermining or biasing the model predictions. The simulation, which extends from the surface to an altitude of 58 km, includes the troposphere as a source of gases and condensation nuclei and as a sink for aerosol droplets. The size distribution of aerosol particles is resolved into 25 categories with particle radii increasing geometrically from 0.01 to 2.56 microns such that particle volume doubles between categories.

  12. The regional distribution characteristics of aerosol optical depth over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Xu, C.; Ma, Y. M.; You, C.; Zhu, Z. K.

    2015-10-01

    The Tibetan Plateau (TP) is representative of typical clean atmospheric conditions. Aerosol optical depth (AOD) retrieved by the Multi-angle Imaging SpectroRadiometer (MISR) is higher over Qaidam Basin than the rest of the TP throughout the year. Different monthly variation patterns of AOD are observed over the southern and northern TP, whereby the aerosol load is usually higher in the northern TP than in the southern part. The aerosol load over the northern part increases from April to June, peaking in May. The maximum concentration of aerosols over the southern TP occurs in July. Aerosols appear to be more easily transported to the main body of the TP across the northern edge rather than the southern edge. This is maybe partly because the altitude is lower at the northern edge than that of the Himalayas located along the southern edge of the TP. Three-dimensional distributions of dust, polluted dust, polluted continental aerosol and smoke are also investigated, based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data. Dust is found to be the most prominent aerosol type on the TP, and other types of aerosols affect the atmospheric environment slightly. A dividing line of higher dust occurrence in the northern TP and lower dust occurrence in the southern TP can be observed clearly at an altitude of 6-8 km above sea level, especially in spring and summer. This demarcation appears around 33-35° N in the middle of the plateau, and it is possibly associated with the high-altitude terrain in the same geographic location. Comparisons of CALIPSO and MISR data show that the vertical dust occurrences are consistent with the spatial patterns of AOD. The different seasonal variation patterns between the northern and southern TP are primarily driven by atmospheric circulation, and are also related to the emission characteristics over the surrounding regions.

  13. Extracting atmospheric turbulence and aerosol characteristics from passive imagery

    NASA Astrophysics Data System (ADS)

    Reinhardt, Colin N.; Wayne, D.; McBryde, K.; Cauble, G.

    2013-09-01

    Obtaining accurate, precise and timely information about the local atmospheric turbulence and extinction conditions and aerosol/particulate content remains a difficult problem with incomplete solutions. It has important applications in areas such as optical and IR free-space communications, imaging systems performance, and the propagation of directed energy. The capability to utilize passive imaging data to extract parameters characterizing atmospheric turbulence and aerosol/particulate conditions would represent a valuable addition to the current piecemeal toolset for atmospheric sensing. Our research investigates an application of fundamental results from optical turbulence theory and aerosol extinction theory combined with recent advances in image-quality-metrics (IQM) and image-quality-assessment (IQA) methods. We have developed an algorithm which extracts important parameters used for characterizing atmospheric turbulence and extinction along the propagation channel, such as the refractive-index structure parameter C2n , the Fried atmospheric coherence width r0 , and the atmospheric extinction coefficient βext , from passive image data. We will analyze the algorithm performance using simulations based on modeling with turbulence modulation transfer functions. An experimental field campaign was organized and data were collected from passive imaging through turbulence of Siemens star resolution targets over several short littoral paths in Point Loma, San Diego, under conditions various turbulence intensities. We present initial results of the algorithm's effectiveness using this field data and compare against measurements taken concurrently with other standard atmospheric characterization equipment. We also discuss some of the challenges encountered with the algorithm, tasks currently in progress, and approaches planned for improving the performance in the near future.

  14. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    NASA Astrophysics Data System (ADS)

    Cao, J.-J.; Zhu, C.-S.; Tie, X.-X.; Geng, F.-H.; Xu, H.-M.; Ho, S. S. H.; Wang, G.-H.; Han, Y.-M.; Ho, K.-F.

    2012-07-01

    An intensive investigation of carbonaceous PM2.5 and TSP from Pudong (China) was conducted as part of the MIRAGE-Shanghai Experiment in 2009. Data for organic and elemental carbon (OC and EC), organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs), and stable C isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA); high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = -24.5 ± 0.8‰ and δ13CEC = -25.1 ± 0.6‰) indicated that fossil fuels were the most important source for carbonaceous PM2.5, with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%: other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  15. Characteristics and Composition of Atmospheric Aerosols in Phimai, Central Thailand During BASE-ASIA

    NASA Technical Reports Server (NTRS)

    Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.; Bell, Shaun W.

    2012-01-01

    Popular summary: Atmospheric aerosols play an important role in the Earth's climate system, and can also have adverse effects on air quality and human health. The environmental impacts of aerosols, on the other hand, are highly regional, since their temporal/spatial distribution is inhomogeneous and highly depends on the regional emission sources. To better understand the effects of aerosols, intensive field experiments are necessary to characterize the chemical and physical properties on a region-by-region basis. From late February to early May in 2006, NASA/GSFC's SMARTLabs facility was deployed at a rural site in central Thailand, Southeast Asia, to conduct a field experiment dubbed BASE-ASIA (Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment). The group was joined by scientists from the University of Hawaii and other regional institutes. Comprehensive measurements were made during the experiment, including aerosol chemical composition, optical and microphysical properties, as well as surface energetics and local . meteorology. This study analyzes part of the data from the BASE-ASIA experiment. It was found that, even for the relatively remote rural site, the aerosol loading was still substantial. Besides agricultural burning in the area, industrial pollution near the Bangkok metropolitan area, about 200 km southeast of the site, and even long-range transport from China, also contribute to the area's aerosol loading. The results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow. Abstract: Comprehensive measurements of atmospheric aerosols were made in Phimai, central Thailand (15.l83 N, 102.565 E, elevation: 206 m) during the BASE-ASIA field experiment from late February to early May in 2006. The observed aerosol loading was sizable for this rural site (mean aerosol scattering: 108 +/- 64 Mm(exp -1); absorption: 15

  16. Assessment of aerosol optical and micro-physical features retrieved from direct and diffuse solar irradiance measurements from Skyradiometer at a high altitude station at Merak: Assessment of aerosol optical features from Merak.

    PubMed

    Ningombam, Shantikumar S; Srivastava, A K; Bagare, S P; Singh, R B; Kanawade, V P; Dorjey, Namgyal

    2015-11-01

    Optical and micro-physical features of aerosol are reported using Skyradiometer (POM-01L, Prede, Japan) observations taken from a high-altitude station Merak, located in north-eastern Ladakh of the western trans-Himalayas region during January 2011 to December 2013. The observed daily mean aerosol optical depth (AOD, at 500 nm) at the site varied from 0.01 to 0.14. However, 75 % of the observed AOD lies below 0.05 during the study period. Seasonal peaks of AOD occurred in spring as 0.06 and minimum in winter as 0.03 which represents the aged background aerosols at the site. Yearly mean AOD at 500 nm is found to be around 0.04 and inter-annual variations of AOD is very small (nearly ±0.01). Angstrom exponent (a) varied seasonally from 0.73 in spring to 1.5 in autumn. About 30 % of the observed a lies below 0.8 which are the indicative for the presence of coarse-mode aerosols at the site. The station exhibits absorbing aerosol features which prominently occurred during spring and that may be attributed by the transported anthropogenic aerosol from Indo-Gangatic Plain (IGP). Results were well substantiated with the air mass back-trajectory analysis. Furthermore, seasonal mean of single scattering albedo (SSA at 500 nm) varied from of 0.94 to 0.98 and a general increasing trend is noticed from 400 to 870 nm wavelengths. These features are apparently regional characteristics of the site. Aerosol asymmetry factor (AS) decreases gradually from 400 to 870 nm and varied from 0.66 to 0.69 at 500 nm across the seasons. Dominance of desert-dust aerosols, associated by coarse mode, is indicated by tri-modal features of aerosol volume size distribution over the station during the entire seasons. PMID:26081773

  17. Composition and spectral characteristics of ambient aerosol at Mauna Loa Observatory

    SciTech Connect

    Johnson, S.A.; Kumar, R. )

    1991-03-20

    Ambient aerosol particles were sampled continuously with a time resolution of {approximately}4 hours for a period of 8 days at the Mauna Loa Observatory, Hawaii, in August 1986. The samples were analyzed on-site for their chemical composition by attenuated total internal reflection infrared spectroscopy. The infrared absorption spectra of the samples also provided data on aerosol light absorbance characteristics at 9.1 and 10.6 {mu}m - wavelengths of interest in determining aerosol backscatter coefficients for CO{sub 2} lidars. The chemical species in the ambient aerosol varied considerably during this 8-day period. The aerosol was acidic ((NH{sub 4}){sub 3}H(SO{sub 4}){sub 2},NH{sub 4}HSO{sub 4}, or H{sub 2}SO{sub 4}) rather than neutral ((NH{sub 4}){sub 2}SO{sub 4}) for a major fraction of the sampling time. The samples generally showed much higher absorbance at 9.1 {mu}m than at 10.6 {mu}m. Changes in the chemical composition between (NH{sub 4}){sub 2}SO{sub 4} and the more acidic forms were accompanied by substantial changes in the sample's absorbance at 9.1 {mu}m but lesser changes in the absorbance at 10.6 {mu}m. These variations could have a profound effect on backscatter coefficients of atmospheric aerosol particles at CO{sub 2} wavelengths.

  18. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    NASA Astrophysics Data System (ADS)

    Cao, J.-J.; Zhu, C.-S.; Tie, X.-X.; Geng, F.-H.; Xu, H.-M.; Ho, S. S. H.; Wang, G.-H.; Han, Y.-M.; Ho, K.-F.

    2013-01-01

    An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles) from Pudong (China) was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment) experiment in 2009. Data for organic and elemental carbon (OC and EC), organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs), and stable carbon isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA); high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = -24.5 ± 0.8‰ and δ13CEC = -25.1 ± 0.6‰) indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter), with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  19. The regional distribution characteristics of aerosol optical depth over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Xu, Chao; Ma, Yaoming; You, Chao; Zhu, Zhikun

    2016-04-01

    The Tibetan Plateau (TP) is representative of typical clean atmospheric conditions. Aerosol optical depth (AOD) retrieved by Multi-angle Imaging SpectroRadiometer (MISR) is higher over Qaidam Basin than the rest of the TP all the year. Different monthly variation patterns of AOD are observed over the southern and northern TP, whereby the aerosol load is usually higher in the northern TP than in the southern part. The aerosol load over the northern part increases from April to June, peaking in May. The maximum concentration of aerosols over the southern TP occurs in July. Aerosols appear to be more easily transported to the main body of the TP across the northern edge rather than the southern edge. This is may be partly because the altitude is lower at the northern edge than that of the Himalayas located along the southern edge of the TP. Three-dimensional distributions of dust, polluted dust, polluted continental and smoke are also investigated based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data. Dust is found to be the most prominent aerosol type on the TP, and other types of aerosols affect the atmospheric environment slightly. A dividing line of higher dust occurrence in the northern TP and lower dust occurrence in the southern TP can be observed clearly at altitude of 6-8 km above sea level, especially in spring and summer. This demarcation appears around 33-35°N in the middle of the plateau, and it is possibly associated with the high altitude terrain in the same geographic location. Comparisons of CALIPSO and MISR data show that the vertical dust occurrences are consistent with the spatial patterns of AOD. The different seasonal variation patterns between the northern and southern TP are primarily driven by atmospheric circulation, and are also related to the emission characteristics over the surrounding regions.

  20. Comprehensive tool for calculation of radiative fluxes: illustration of shortwave aerosol radiative effect sensitivities to the details in aerosol and underlying surface characteristics

    NASA Astrophysics Data System (ADS)

    Derimian, Yevgeny; Dubovik, Oleg; Huang, Xin; Lapyonok, Tatyana; Litvinov, Pavel; Kostinski, Alex B.; Dubuisson, Philippe; Ducos, Fabrice

    2016-05-01

    The evaluation of aerosol radiative effect on broadband hemispherical solar flux is often performed using simplified spectral and directional scattering characteristics of atmospheric aerosol and underlying surface reflectance. In this study we present a rigorous yet fast computational tool that accurately accounts for detailed variability of both spectral and angular scattering properties of aerosol and surface reflectance in calculation of direct aerosol radiative effect. The tool is developed as part of the GRASP (Generalized Retrieval of Aerosol and Surface Properties) project. We use the tool to evaluate instantaneous and daily average radiative efficiencies (radiative effect per unit aerosol optical thickness) of several key atmospheric aerosol models over different surface types. We then examine the differences due to neglect of surface reflectance anisotropy, nonsphericity of aerosol particle shape and accounting only for aerosol angular scattering asymmetry instead of using full phase function. For example, it is shown that neglecting aerosol particle nonsphericity causes mainly overestimation of the aerosol cooling effect and that magnitude of this overestimate changes significantly as a function of solar zenith angle (SZA) if the asymmetry parameter is used instead of detailed phase function. It was also found that the nonspherical-spherical differences in the calculated aerosol radiative effect are not modified significantly if detailed BRDF (bidirectional reflectance distribution function) is used instead of Lambertian approximation of surface reflectance. Additionally, calculations show that usage of only angular scattering asymmetry, even for the case of spherical aerosols, modifies the dependence of instantaneous aerosol radiative effect on SZA. This effect can be canceled for daily average values, but only if sun reaches the zenith; otherwise a systematic bias remains. Since the daily average radiative effect is obtained by integration over a range

  1. Mass concentration and mineralogical characteristics of aerosol particles collected at Dunhuang during ACE-Asia

    NASA Astrophysics Data System (ADS)

    Shen, Z. X.; Cao, J. J.; Li, X. X.; Okuda, T.; Wang, Y. Q.; Zhang, X. Y.

    2006-03-01

    Measurements were performed in spring 2001 and 2002 to determine the characteristics of soil dust in the Chinese desert region of Dunhuang, one of the ground sites of the Asia-Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The mean mass concentrations of total suspended particle matter during the spring of 2001 and 2002 were 317 mu g m(-3) and 307 mu g m(-3) respectively. Eleven dust storm events were observed with a mean aerosol concentration of 1095 mu g m(-3), while the non-dusty days with calm or weak wind speed had a background aerosol loading of 196 mu g m(-3) on average in the springtime. The main minerals detected in the aerosol samples by X-ray diffraction were illite, kaolinite, chlorite, quartz, feldspar, calcite and dolomite. Gypsum, halite and amphibole were also detected in a few samples. The mineralogical data also show that Asian dust is characterized by a kaolinite to chlorite (K/C) ratio lower than 1 whereas Saharan dust exhibits a K/C ratio larger than 2. Air mass back- trajectory analysis show that three families of pathways are associated with the aerosol particle transport to Dunhuang, but these have similar K/C ratios, which further demonstrates that the mineralogical characteristics of Asian dust are different from African dust.

  2. [Pollution characteristics of microbial aerosols generated from a municipal sewage treatment plant].

    PubMed

    Qiu, Xiong-Hui; Li, Yan-Peng; Niu, Tie-Jun; Li, Mei-Ling; Ma, Zhi-Hui; Miao, Ying; Wang, Xiang-Jun

    2012-07-01

    To characterize the pollution characteristics of microbial aerosols emitted from municipal sewage treatment plants, microbial aerosols were sampled with an Andersen 6-stage impactor at different treatment units of a Xi'an sewage treatment plant between June 2011 and July 2011. The plate-culture and colony-counting methods were employed to determine the concentrations, particle size distributions and median diameters of the airborne bacteria, fungi and actinomycetes. The results showed that the highest concentrations of bacteria (7 866 CFU x m(-3) +/- 960 CFU x m(-3)) and actinomycetes (2 139 CFU x m(-3) +/- 227 CFU x m(-3)) were found in the sludge-dewatering house while the highest fungi concentration (2156 CFU x m(-3) +/- 119 CFU x m(-3)) in the oxidation ditch. The airborne bacteria, fungi and actinomycetes all showed a skewed distribution in particle size. The peaks of bacteria and fungi were in the size range of 2.1-3.3 microm, whereas the peak of airborne actinomycetes was between 1. 1-2.1 microm in size. In general, the order of the median diameters of different microbial aerosols generated from the sewage treatment plant was airborne bacteria > airborne fungi > airborne actinomycetes. In addition, the spatial variation characteristics of microbial aerosols showed that the larger the particle size of the microorganism, the faster the reducing rate of the aerosol concentration. The variations in the reducing rate of concentration with particle sizes can be ordered as airborne bacteria > airborne fungi > airborne actinomycetes. PMID:23002590

  3. Columnar characteristics of aerosols by spectroradiometer measurements in the maritime area of the Cadiz Gulf (Spain)

    NASA Astrophysics Data System (ADS)

    Vergaz, Ricardo; Cachorro, Victoria E.; de Frutos, Ángel M.; Vilaplana, José M.; de La Morena, Benito A.

    2005-11-01

    Atmospheric aerosol characteristics represented by the spectral aerosol optical depth AOD) and the Ångström turbidity parameter were determined in the coastal area of the Gulf of Cádiz, (southwest of Spain). The columnar aerosol properties presented here correspond to the 1996-1999 period, and were obtained by solar direct irradiance measurements carried out by a Licor1800 spectroradiometer. The performance of this type of medium-spectral resolution radiometric system is analysed over the measured period. The detailed spectral information of these irradiance measurements enabled the use of selected non-absorption gases spectral windows to determine the columnar spectral AOD that was modelled by Ångström formula to obtain the coefficient. Temporal evolutions of instantaneous values together with a general statistical analysis represented by seasonal values, frequency distributions and some representative correlations for the AOD and the derived Ångström coefficient gave us the first insight of aerosol characteristics in this coastal area. Special attention was paid to the analysis of these aerosol properties at the nominal wavelengths of 440 nm, 670 nm, 870 nm and 1020 nm for the near-future comparisons with the Cimel sun-photometer data. However, taking the most representative aerosol wavelength of 500 nm, the variability of the AOD ranges from 0.005 to 0.53, with a mean of 0.12 (s.d = 0.07) and that of the parameter is given by a mean value of 0.93 (s.d. = 0.58) falling inside the range of marine aerosols. A quantitative discrimination of aerosol types was conducted on the basis of the spectral aerosol properties and air mass back trajectory analysis, which resulted in a mixed type because of the specificity of this area, given by very frequent desert dust episodes, continental and polluted local influences. This study represents the first extended data characterization about columnar properties of aerosols in Spain which has been continued by Cimel

  4. Physicochemical characteristics of aerosol particles generated during the milling of beryllium silicate ores: implications for risk assessment.

    PubMed

    Stefaniak, Aleksandr B; Chipera, Steve J; Day, Gregory A; Sabey, Phil; Dickerson, Robert M; Sbarra, Deborah C; Duling, Mathew G; Lawrence, Robert B; Stanton, Marcia L; Scripsick, Ronald C

    2008-01-01

    Inhalation of beryllium dusts generated during milling of ores and cutting of beryl-containing gemstones is associated with development of beryllium sensitization and low prevalence of chronic beryllium disease (CBD). Inhalation of beryllium aerosols generated during primary beryllium production and machining of the metal, alloys, and ceramics are associated with sensitization and high rates of CBD, despite similar airborne beryllium mass concentrations among these industries. Understanding the physicochemical properties of exposure aerosols may help to understand the differential immunopathologic mechanisms of sensitization and CBD and lead to more biologically relevant exposure standards. Properties of aerosols generated during the industrial milling of bertrandite and beryl ores were evaluated. Airborne beryllium mass concentrations among work areas ranged from 0.001 microg/m(3) (beryl ore grinding) to 2.1 microg/m(3) (beryl ore crushing). Respirable mass fractions of airborne beryllium-containing particles were < 20% in low-energy input operation areas (ore crushing, hydroxide product drumming) and > 80% in high-energy input areas (beryl melting, beryl grinding). Particle specific surface area decreased with processing from feedstock ores to drumming final product beryllium hydroxide. Among work areas, beryllium was identified in three crystalline forms: beryl, poorly crystalline beryllium oxide, and beryllium hydroxide. In comparison to aerosols generated by high-CBD risk primary production processes, aerosol particles encountered during milling had similar mass concentrations, generally lower number concentrations and surface area, and contained no identifiable highly crystalline beryllium oxide. One possible explanation for the apparent low prevalence of CBD among workers exposed to beryllium mineral dusts may be that characteristics of the exposure material do not contribute to the development of lung burdens sufficient for progression from sensitization to

  5. Observed changes in aerosol physical and optical properties before and after precipitation events

    NASA Astrophysics Data System (ADS)

    Li, Xingmin; Dong, Yan; Dong, Zipeng; Du, Chuanli; Chen, Chuang

    2016-08-01

    Precipitation scavenging of aerosol particles is an important removal process in the atmosphere that can change aerosol physical and optical properties. This paper analyzes the changes in aerosol physical and optical properties before and after four rain events using in situ observations of mass concentration, number concentration, particle size distribution, scattering and absorption coefficients of aerosols in June and July 2013 at the Xianghe comprehensive atmospheric observation station in China. The results show the effect of rain scavenging is related to the rain intensity and duration, the wind speed and direction. During the rain events, the temporal variation of aerosol number concentration was consistent with the variation in mass concentration, but their size-resolved scavenging ratios were different. After the rain events, the increase in aerosol mass concentration began with an increase in particles with diameter <0.8 μm [measured using an aerodynamic particle sizer (APS)], and fine particles with diameter <0.1 μm [measured using a scanning mobility particle sizer (SMPS)]. Rainfall was most efficient at removing particles with diameter ~0.6 μm and greater than 3.5 μm. The changes in peak values of the particle number distribution (measured using the SMPS) before and after the rain events reflect the strong scavenging effect on particles within the 100-120 nm size range. The variation patterns of aerosol scattering and absorption coefficients before and after the rain events were similar, but their scavenging ratios differed, which may have been related to the aerosol particle size distribution and chemical composition.

  6. Modal characteristics of carbonaceous aerosol size distribution in an urban atmosphere of South China

    NASA Astrophysics Data System (ADS)

    Lan, Zi-Juan; Chen, Dong-Lei; Li, Xiang; Huang, Xiao-Feng; He, Ling-Yan; Deng, Yan-Ge; Feng, Ning; Hu, Min

    2011-04-01

    Size distributions can provide important information about aerosol sources, formation, and growth mechanisms. However, compared to size distributions of inorganic aerosols, size distributions of carbonaceous aerosols have been much less studied and reported in the literature. In this paper, we systematically measured size distributions of elemental carbon (EC), organic carbon (OC), oxalate, polycyclic aromatic hydrocarbons (PAHs), as well as major inorganic ions in urban aerosols in Shenzhen, China. Totally 24 sets of samples were collected using a ten-stage micro orifice uniform deposit impactor (MOUDI) during October 2009 to February 2010. Three lognormal modes contained in the size distributions of species were resolved based on positive matrix factorization (PMF) analysis of the measured dataset, corresponding to the condensation (peak = 0.34 μm), droplet (peak = 0.84 μm), and coarse (peak = 5.4 μm) modes, respectively. The mean concentrations of EC in the condensation, droplet, and coarse modes were 2.20, 1.18, and 0.64 μg m -3, respectively, and the modal characteristics of EC indicate that fresher local combustion emissions contributed mostly to aerosol EC in the urban atmosphere of Shenzhen. The mean concentrations of OC in the condensation, droplet, and coarse modes were 2.29, 3.34, and 3.51 μg m -3, respectively, and the modal characteristics of OC indicate that its sources were more primary in the condensation mode while more secondary in the droplet mode. The modal characteristics of aerosol oxalate and PAHs suggest that they were predominantly from in-cloud secondary formation and local emissions, respectively.

  7. Characteristics of Submicron Aerosols in 2013 summer of Beijing

    NASA Astrophysics Data System (ADS)

    Guo, Song; Hu, Min; Shang, Dongjie; Zheng, Jing; Du, Zhuofei; Wu, Yusheng; Lu, Sihua; Zeng, Limin; Zhang, Renyi

    2016-04-01

    To characterize the air pollution of North China Plain of China, CAREBEIJING-2013 field campaign (Campaigns of Air quality REsearch in BEIJING and surrounding region) was conducted in summer of 2013. Submicron aerosols were measured at an urban site PKU (Peking University, 39° 59'21"N, 116° 18'25"E) from July 28th to September 31st 2013. A suite of integrated instruments was used to measure the size distribution, effective density and hygroscopicity of ambient particles. The chemical composition of submicron particles were measured by using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) (Billerica, MA, USA). The average PM2.5 concentration was 73.0±70.7 μg m‑3 during the measurement. The particulate pollution showed distinct 4-7 days cycles controlled by the meteorological conditions. Each cycle started with low PM2.5 mass concentrations (<20 μg m‑3), since the air mass was from relatively clean mountainous area. The particle number concentrations were high, but and the sizes were small (<30 nm) at this stage, which can be explained by the new particle formation. In the succeeding days, both the particle mass and size continuously increased. The PM2.5concentration increased rapidly by >60 μg day‑1, and the particle mean diameter grew to >100 nm. It is interesting to note that the mean diameters showed similar trend to PM2.5 mass concentrations, indicating the particle pollution attributed to the growth of the newly formed small particles. During the measurement, the average particle densities are between 1.3-1.5 g cm‑3, indicating organics and sulfate were dominant in the particles. The densities of smaller particles, i.e. 46 nm, 81nm, showed single peak at 1.3-1.5 g cm‑3, indicating the particles are internal mixed sulfate and organics. While the 150nm and 240 nm particle densities exhibited bimodal distribution with an additional small peak at ˜1.1 g cm‑3, which is considered as external mixed organic

  8. Optical characteristics of aerosol trioxide dialuminum at the IR wavelength range

    NASA Astrophysics Data System (ADS)

    Voitsekhovskaya, O. K.; Shefer, O. V.; Kashirskii, D. E.

    2015-11-01

    In this work, a numerical study of the transmission function, extinction coefficient, scattering coefficient, and absorption coefficient of the aerosol generated by the jet engine emissions was performed. Analyzing the calculation results of the IR optical characteristics of anthropogenic emissions containing the dialuminum trioxide was carried out. The spectral features of the optical characteristics of the medium caused by the average size, concentration and complex refractive index of the particles were illustrated.

  9. Characteristics of 2-methyltetrols in ambient aerosol in Beijing, China

    NASA Astrophysics Data System (ADS)

    Liang, Linlin; Engling, Guenter; Duan, Fengkui; Cheng, Yuan; He, Kebin

    2012-11-01

    PM10 and PM2.5 samples were collected from November, 2010 to October, 2011 at Tsinghua University in Beijing. Various carbohydrates were quantified by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), including the 2-methyltetrols (2-methylthreitol and 2-methylerythritol). A clear seasonal variation in the ambient 2-methyltetrol concentrations was observed, with the highest levels occurring in the summer, followed by autumn, spring and winter. The average concentrations of the 2-methyltetrols in PM10 and PM2.5 were 17.5 ± 15.4 ng m-3 and 13.8 ± 12.2 ng m-3, respectively. The 2-methyltetrols exhibited significant positive correlations with ambient relative humidity and temperature, likely due to the higher isoprene emission strength and enhanced formation yield under higher temperature and humidity conditions. In contrast, there was no relationship between the concentration of 2-methyltetrols and sunshine duration. The significant positive correlation (R2 = 0.76) between 2-methyltetrols and SO42- indicated that high concentrations of SO42- can increase the formation rate of 2-methyltetrols from isoprene. Moreover, 2-methyltetrols were also observed in the winter time in Beijing, illustrating the enhancement of the 2-methyltetrol formation rate by high concentrations of pollutants in ambient aerosol.

  10. Winter time chemical characteristics of aerosols over the Bay of Bengal: continental influence.

    PubMed

    Aryasree, S; Nair, Prabha R; Girach, I A; Jacob, Salu

    2015-10-01

    As part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) conducted under the Geosphere Biosphere Programme of Indian Space Research Organisation, ship-based aerosol sampling was carried out over the marine environment of Bay of Bengal (BoB) during the northern winter months of December 2008 to January 2009. About 101 aerosol samples were collected, covering the region from 3.4° to 21° N latitude and 76° to 98° E longitude-the largest area covered-including the south east (SE) BoB for the first time. These samples were subjected to gravimetric and chemical analysis and the total aerosol loading as well the mass concentration of the ionic species namely F(-), Cl(-), Br(-), NO2 (-), NO3 (-), PO4 (2-), SO4 (2-), NH4 (+), etc. and the metallic species, Na, Mg, Ca, K, Al, Fe, Mn, Zn, and Pb were estimated for each sample. Based on the spatial distribution of individual chemical species, the air flow pattern, and airmass back trajectory analysis, the source characteristics of aerosols for different regions of BoB were identified. Significant level of continental pollution was noticed over BoB during winter. While transport of pollution from Indo-Gangetic Plain (IGP) contributed to aerosols over north BoB, those over SE BoB were influenced by SE Asia. A quantitative study on the wind-induced production of sea salt aerosols and a case study on the species dependent effect of rainfall are also presented in this paper. PMID:25994269

  11. Vegetation fires, absorbing aerosols and smoke plume characteristics in diverse biomass burning regions of Asia

    NASA Astrophysics Data System (ADS)

    Prasad Vadrevu, Krishna; Lasko, Kristofer; Giglio, Louis; Justice, Chris

    2015-10-01

    In this study, we explored the relationships between the satellite-retrieved fire counts (FC), fire radiative power (FRP) and aerosol indices using multi-satellite datasets at a daily time-step covering ten different biomass burning regions in Asia. We first assessed the variations in MODIS-retrieved aerosol optical depths (AOD’s) in agriculture, forests, plantation and peat land burning regions and then used MODIS FC and FRP (hereafter FC/FRP) to explain the variations in AOD characteristics. Results suggest that tropical broadleaf forests in Laos burn more intensively than the other vegetation fires. FC/FRP-AOD correlations in different agricultural residue burning regions did not exceed 20% whereas in forest regions they reached 40%. To specifically account for absorbing aerosols, we used Ozone Monitoring Instrument-derived aerosol absorption optical depth (AAOD) and UV aerosol index (UVAI). Results suggest relatively high AAOD and UVAI values in forest fires compared with peat and agriculture fires. Further, FC/FRP could explain a maximum of 29% and 53% of AAOD variations, whereas FC/FRP could explain at most 33% and 51% of the variation in agricultural and forest biomass burning regions, respectively. Relatively, UVAI was found to be a better indicator than AOD and AAOD in both agriculture and forest biomass burning plumes. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations data showed vertically elevated aerosol profiles greater than 3.2-5.3 km altitude in the forest fire plumes compared to 2.2-3.9 km and less than 1 km in agriculture and peat-land fires, respectively. We infer the need to assimilate smoke plume height information for effective characterization of pollutants from different sources.

  12. Teachers' and Students' Perceptions of Effective Physics Teacher Characteristics

    ERIC Educational Resources Information Center

    Korur, Fikret; Eryilmaz, Ali

    2012-01-01

    Problem Statement: What do teachers and students in Turkey perceive as the common characteristics of effective physics teachers? Purpose of Study: The first aim was to investigate the common characteristics of effective physics teachers by asking students and teachers about the effects of teacher characteristics on student physics achievement and…

  13. 40 CFR 161.190 - Physical and chemical characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Physical and chemical characteristics... Requirements § 161.190 Physical and chemical characteristics. (a) Table. Sections 161.100 through 161.102 describe how to use this table to determine the physical and chemical characteristics data requirements...

  14. 40 CFR 161.190 - Physical and chemical characteristics.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Physical and chemical characteristics... Requirements § 161.190 Physical and chemical characteristics. (a) Table. Sections 161.100 through 161.102 describe how to use this table to determine the physical and chemical characteristics data requirements...

  15. Filter and electrostatic samplers for semivolatile aerosols: physical artifacts.

    PubMed

    Volckens, John; Leith, David

    2002-11-01

    Adsorptive and evaporative artifacts often bias measurements of semivolatile aerosols. Adsorption occurs when the sampling method disrupts the gas-particle partitioning equilibrium. Evaporation occurs because concentrations of semivolatiles are rarely constant over time. Filtration is subject to both adsorptive and evaporative artifacts. By comparison, electrostatic precipitation reduces these artifacts by minimizing the surface area of collected particles without substantially disrupting the gas-particle equilibrium. The extent of these artifacts was determined for filter samplers and electrostatic precipitator samplers for semivolatile alkane aerosols in the laboratory. Adsorption of gas-phase semivolatiles was lower in electrostatic precipitators by factors of 5-100 compared to the filter method. Particle evaporation from the electrostatic sampler was 2.3 times lower than that from TFE-coated glass-fiber filters. Use of a backup filter to correct for compound-specific adsorption artifacts can introduce positive or negative errors to the measured particle-phase concentration due to competition among the adsorbates for available adsorption sites. Adsorption of evaporated particles from the front filter onto the backup filter increased the measured evaporative artifact by a factor of 1.5-2. PMID:12433172

  16. Aerosol physical, chemical and optical properties observed in the ambient atmosphere during haze pollution conditions

    NASA Astrophysics Data System (ADS)

    Li, Zhengqiang; Xie, Yisong; Li, Donghui; Li, Kaitao; Zhang, Ying; Li, Li; Lv, Yang; Qie, Lili; Xu, Hua

    Aerosol’s properties in the ambient atmosphere may differ significantly from sampling results due to containing of abundant water content. We performed sun-sky radiometer measurements in Beijing during 2011 and 2012 winter to obtain distribution of spectral and angular sky radiance. The measurements are then used to retrieve aerosol physical, chemical and optical properties, including single scattering albedo, size distribution, complex refractive indices and aerosol component fractions identified as black carbon, brown carbon, mineral dust, ammonium sulfate-like components and water content inside particle matters. We found that during winter haze condition aerosol is dominated by fine particles with center radius of about 0.2 micron. Fine particles contribute about 93% to total aerosol extinction of solar light, and result in serious decrease of atmospheric visibility during haze condition. The percentage of light absorption of haze aerosol can up to about 10% among its total extinction, much higher than that of unpolluted conditions, that causes significant radiative cooling effects suppressing atmospheric convection and dispersion of pollutants. Moreover, the average water content occupies about one third of the ambient aerosol in volume which suggests the important effect of ambient humidity in the formation of haze pollution.

  17. [Characteristics of Number Concentration Size Distributions of Aerosols Under Processes in Beijing].

    PubMed

    Su, Jie; Zhao, Pu-sheng; Chen, Yi-na

    2016-04-15

    The aerosol number concentration size distributions were measured by a Wide-Range Particle Spectrometer (WPS-1000XP) at an urban site of Beijing from 2012 to 2014; and the characteristics of the size distributions in different seasons and weather conditions were discussed. The results showed that the daily average number concentration of Aitken mode aerosols was highest in the spring and lowest in the autumn; the daily average number concentration of accumulation mode aerosols was bigher in the spring and winter, while lowest in summer; and the average concentration of coarse mode was highest during the winter. The Aitken mode particles had the most significant diurnal variations resulted from the traffic sources and the summer photochemical reactions. In the spring, autumn and winter, the number concentrations of accumulation mode of the nighttime was higher than that of the daytime. The coarse mode particles did not have obvious diurnal variation. During the heavy pollution process, the accumulation mode aerosols played a decisive role in PM₂.₅ concentrations and was usually removed by the north wind. The precipitation could effectively eliminate the coarse mode particles, but it bad no obvious effect on the accumulation mode particles under small speed wind and zero speed wind. During the dust process, the concentrations of coarse mode particles increased significantly, while the accumulation mode aerosol concentration was obviously decreased. PMID:27548939

  18. Formation characteristics of aerosol particles from pulverized coal pyrolysis in high-temperature environments

    SciTech Connect

    Wei-Hsin Chen; Shan-Wen Du; Hsi-Hsien Yang; Jheng-Syun Wu

    2008-05-15

    The formation characteristics of aerosol particles from pulverized coal pyrolysis in high temperatures are studied experimentally. By conducting a drop-tube furnace, fuel pyrolysis processes in industrial furnaces are simulated in which three different reaction temperatures of 1000, 1200, and 1400{sup o}C are considered. Experimental observations indicate that when the reaction temperature is 1000{sup o}C, submicron particles are produced, whereas the particle size is dominated by nanoscale for the temperature of 1400{sup o}C. Thermogravimetric analysis of the aerosol particles stemming from the pyrolysis temperature of 1000{sup o}C reveals that the thermal behavior of the aerosol is characterized by a three-stage reaction with increasing heating temperature: (1) a volatile-reaction stage, (2) a weak-reaction stage, and (3) a soot-reaction stage. However, with the pyrolysis temperature of 1400{sup o}C, the volatile- and weak-reaction stages almost merge together and evolve into a chemical-frozen stage. The submicron particles (i.e., 1000{sup o}C) are mainly composed of volatiles, tar, and soot, with the main component of the nanoscale particles (i.e., 1400{sup o}C) being soot. The polycyclic aromatic hydrocarbons (PAHs) contained in the aerosols are also analyzed. It is found that the PAH content in generated aerosols decreases dramatically as the pyrolysis temperature increases. 31 refs., 9 figs., 1 tab.

  19. Modelling of primary aerosols in the chemical transport model MOCAGE: development and evaluation of aerosol physical parameterizations

    NASA Astrophysics Data System (ADS)

    Sič, B.; El Amraoui, L.; Marécal, V.; Josse, B.; Arteta, J.; Guth, J.; Joly, M.; Hamer, P. D.

    2015-02-01

    This paper deals with recent improvements to the global chemical transport model of Météo-France MOCAGE (Modèle de Chimie Atmosphérique à Grande Echelle) that consists of updates to different aerosol parameterizations. MOCAGE only contains primary aerosol species: desert dust, sea salt, black carbon, organic carbon, and also volcanic ash in the case of large volcanic eruptions. We introduced important changes to the aerosol parameterization concerning emissions, wet deposition and sedimentation. For the emissions, size distribution and wind calculations are modified for desert dust aerosols, and a surface sea temperature dependant source function is introduced for sea salt aerosols. Wet deposition is modified toward a more physically realistic representation by introducing re-evaporation of falling rain and snowfall scavenging and by changing the in-cloud scavenging scheme along with calculations of precipitation cloud cover and rain properties. The sedimentation scheme update includes changes regarding the stability and viscosity calculations. Independent data from satellites (MODIS, SEVIRI), the ground (AERONET, EMEP), and a model inter-comparison project (AeroCom) are compared with MOCAGE simulations and show that the introduced changes brought a significant improvement on aerosol representation, properties and global distribution. Emitted quantities of desert dust and sea salt, as well their lifetimes, moved closer towards values of AeroCom estimates and the multi-model average. When comparing the model simulations with MODIS aerosol optical depth (AOD) observations over the oceans, the updated model configuration shows a decrease in the modified normalized mean bias (MNMB; from 0.42 to 0.10) and a better correlation (from 0.06 to 0.32) in terms of the geographical distribution and the temporal variability. The updates corrected a strong positive MNMB in the sea salt representation at high latitudes (from 0.65 to 0.16), and a negative MNMB in the desert

  20. PHYSICAL CHARACTERISTICS AND HEALTH EFFECTS OF AEROSOLS FROM COLLAPSED BUILDINGS

    EPA Science Inventory

    Airborne pollutants can rise to extreme levels when large buildings fall down. The terrorist attack on New York's World Trade Center (WTC) towers caused the release of an enormous quantity of pulverized building materials and combustion products into the local environment. Partic...

  1. Physical characteristics of cinnamon oil microcapsule

    NASA Astrophysics Data System (ADS)

    Hermanto, R. F.; Khasanah, L. U.; Kawiji; Atmaka, W.; Manuhara, G. J.; Utami, R.

    2016-02-01

    Cinnamon (Cinnamomum burmanii) oil products can be obtained from the bark by steam distillation. Essential oils are susceptible to high temperatures, oxidation, UV light, and humidity. Microencapsulation may change essential oils into powder, protect the sensitive core material and reduce the amount of flavor which lost during storage. In the microencapsulation, one of the important factors is the type of coating agent. The objective of this work was to characterize the cinnamon oil microcapsule. Ratio variations of coating agent maltodextrin and gum arabic were (1:0); (0:1); (1:1); (2:3). Physical characteristics such as water content, solubility, bulk density, surface oil, and microencapsulation efficiency of samples were investigated. Results showed that the ratio variations of the coating agent significantly affected the water content, bulk density, surface oil and microencapsulation efficiency but significantly affected the water solubility. Characteristics of selected microcapsule were 6.13% water content; 96.33% solubility; 0.46 g/cm3 bulk density; 2.68% surface oil; 70.68% microencapsulation efficiency and microstructures were rather good.

  2. LIDAR Measurements of the Vertical Distribution of Aerosol Optical and Physical Properties over Central Asia

    EPA Science Inventory

    The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM2.5 and PM10 mass and chemical ...

  3. Retrieval of aerosol optical and micro-physical properties with 2D-MAX-DOAS

    NASA Astrophysics Data System (ADS)

    Ortega, Ivan; Coburn, Sean; Hostetler, Chris; Ferrare, Rich; Hair, Johnathan; Kassianov, Evgueni; Barnard, James; Berg, Larry; Schmid, Beat; Tomlinson, Jason; Hodges, Gary; Lantz, Kathy; Wagner, Thomas; Volkamer, Rainer

    2015-04-01

    Recent retrievals of 2 dimensional (2D) Multi-AXis Differential Optical Absorption Spectroscopy (2D-MAX-DOAS) have highlighted its importance in order to infer diurnal horizontal in-homogeneities around the measurement site. In this work, we expand the capabilities of 2D measurements in order to estimate simultaneously aerosol optical and micro-physical properties. Specifically, we present a retrieval method to obtain: (1) aerosol optical thickness (AOT) in the boundary layer (BL) and free troposphere (FT) and (2) the effective complex refractive index and the effective radius of the aerosol column size distribution. The retrieval method to obtain AOT is based on an iterative comparison of measured normalized radiances, oxygen collision pair (O4), and absolute Raman Scattering Probability (RSP) with the forward model calculations derived with the radiative transfer model McArtim based on defined aerosol extinction profiles. Once the aerosol load is determined we use multiple scattering phase functions and single scattering albedo (SSA) obtained with Mie calculations which then constrain the RTM to forward model solar almucantar normalized radiances. The simulated almucantar normalized radiances are then compared to the measured normalized radiances. The best-fit, determined by minimizing the root mean square, retrieves the complex refractive index, and effective radius. We apply the retrieval approach described above to measurements carried out during the 2012 intensive operation period of the Two Column Aerosol Project (TCAP) held on Cape Cod, MA, USA. Results are presented for two ideal case studies with both large and small aerosol loading and similar air mass outflow from the northeast coast of the US over the West Atlantic Ocean. The aerosol optical properties are compared with several independent instruments, including the NASA Langley airborne High Spectral Resolution Lidar (HSRL-2) for highly resolved extinction profiles during the overpasses, and with the

  4. Influence of formulation and preparation process on ambroxol hydrochloride dry powder inhalation characteristics and aerosolization properties.

    PubMed

    Ren, Yachao; Yu, Chaoqun; Meng, Kangkang; Tang, Xing

    2008-09-01

    The objective of this study is to evaluate the influence of formulation and preparation process on ambroxol hydrochloride (AH) dry powder inhalation (DPI) characteristics and aerosolization properties. Spray-dried samples of AH, AH/leucine, and AH/leucine/mannitol were prepared from their corresponding water solutions under the same conditions to study the influence of the composition, and the AH/leucine/mannitol (2.5/0.5/1 by weight) formulation was used for investigation of the effect of the preparation process. Following spray-drying, the resulting powders were characterized using scanning electron microscopy, laser diffraction, tapped density, and angle of repose measurements, and the aerosolization performance was determined using a twin-stage liquid impinger. AH/leucine/mannitol (2.5/0.5/1 by weight) obtained by cospray-drying improved the AH aerosolization properties. The AH/leucine/mannitol (2.5/0.5/1 by weight) preparation exhibited the following properties: 62.34% yield, 0.34 g/cm(3) tap density, 2.71 microm d(ae), 33.45 degrees angle of repose, and 30.93% respirable fraction. The influence of the preparation process on DPI characteristics and aerosolization properties was relatively small, but the influence of the composition was relatively large. Optimization of DPI can be achieved by selecting the most appropriate formulation and preparation process. PMID:18800258

  5. On the Physics of Fizziness: How liquid properties control bursting bubble aerosol production?

    NASA Astrophysics Data System (ADS)

    Ghabache, Elisabeth; Antkowiak, Arnaud; Josserand, Christophe; Seon, Thomas

    2014-11-01

    Either in a champagne glass or at the oceanic scales, the tiny capillary bubbles rising at the surface burst in ejecting myriads of droplets. Focusing on the ejected droplets produced by a single bubble, we investigate experimentally how liquid properties and bubble size affect their characteristics: number, ejection velocities, sizes and ejection heights. These results allow us to finely tune the bursting bubble aerosol production. In the context of champagne industry, aerosols play a major role by spreading wine aroma above the glass. We demonstrate that this champagne fizz can be enhanced by selecting the wine viscosity and the bubble size, thanks to specially designed glass.

  6. Heterogeneity in pre-monsoon aerosol characteristics over the Indo-Gangetic Basin

    NASA Astrophysics Data System (ADS)

    Tiwari, S.; Srivastava, A. K.; Singh, A. K.

    2013-10-01

    Heterogeneity in aerosol characteristics was studied at five different locations over the Indo-Gangetic Basin (IGB) region during the pre-monsoon period (April-June 2011) using concurrent measurements from sun/sky radiometer, which is hypothesized to affect the Indian monsoon circulation and also the global climate system. Based on the measured aerosol products, distribution of aerosols and the associated optical properties were examined over the entire region. The pre-monsoon mean aerosol optical depth (AOD) was found to be maximum at Lahore (0.78) and Kanpur (0.68); however, a minimum AOD (∼0.6) was observed at Karachi, Jaipur and Gandhi College, with relatively high variability at Karachi and low at Gandhi College. On the other hand, a significant gradient in Angstrom exponent (AE) from Karachi (0.30) in the west to Gandhi College (0.98) in the east IGB region suggests relative dominance of coarse particles over the western part and fine particles at the eastern part of the IGB. Results are confirmed with the aerosol size distribution and the air mass back-trajectory analysis at all the stations. The corresponding pre-monsoon mean single scattering albedo (SSA) shows relatively higher value at Karachi (0.94), suggests relative dominance of scattering type particles. On the other hand, lower SSA, ranging from 0.85 to 0.92, was observed at the other stations, with the lowest value at Gandhi College (0.85), which suggests absorbing aerosol distributions over the region.

  7. Correlations between Optical, Chemical and Physical Properties ofBiomass Burn Aerosols

    SciTech Connect

    Hopkins, Rebecca J.; Lewis, K.; Desyaterik, Yury; Wang, Z.; Tivanski, Alexei V.; Arnott, W.P.; Laskin, Alexander; Gilles, M.K.

    2008-01-29

    Aerosols generated from burning different plant fuels were characterized to determine relationships between chemical, optical and physical properties. Single scattering albedo ({omega}) and Angstrom absorption coefficients ({alpha}{sub ap}) were measured using a photoacoustic technique combined with a reciprocal nephelometer. Carbon-to-oxygen atomic ratios, sp{sup 2} hybridization, elemental composition and morphology of individual particles were measured using scanning transmission X-ray microscopy coupled with near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS) and scanning electron microscopy with energy dispersion of X-rays (SEM/EDX). Particles were grouped into three categories based on sp2 hybridization and chemical composition. Measured {omega} (0.4-1.0 at 405 nm) and {alpha}{sub ap} (1.0-3.5) values displayed a fuel dependence. The category with sp{sup 2} hybridization >80% had values of {omega} (<0.5) and {alpha}{sub ap} ({approx}1.25) characteristic of light absorbing soot. Other categories with lower sp2 hybridization (20 to 60%) exhibited higher {omega} (>0.8) and {alpha}{sub ap} (1.0 to 3.5) values, indicating increased absorption spectral selectivity.

  8. Uptake of Organic Vapors by Sulfate Aerosols: Physical and Chemical Processes

    NASA Technical Reports Server (NTRS)

    Michelsen, R. R.; Ashbourn, S. F. M.; Iraci, L.T.; Staton, S. J. R.

    2003-01-01

    While it is known that upper tropospheric sulfate particles contain a significant amount of organic matter, both the source of the organic fraction and its form in solution are unknown. These studies explore how the chemical characteristics of the molecules and surfaces in question affect heterogeneous interactions. The solubilities of acetaldehyde [CH3CHO] and ethanol [CH3CH20H] in cold, aqueous sulfuric acid solutions have been measured by Knudsen cell studies. Henry's law solubility coefficients range from 10(exp 2) to 10(exp 5) M/atm for acetaldehyde, and from 10(exp 4) to 10(exp 9) M/atm for ethanol under upper tropospheric conditions (210-240 K, 40-80 wt. % H2S04). The multiple solvation pathways (protonation, enolization, etc.) available to these compounds in acidic aqueous environments will be discussed. Preliminary results from the interaction of acetaldehyde with solutions of formaldehyde in sulfuric acid will be presented as well. The physical and chemical processes that affect organic uptake by aqueous aerosols will be explored, with the aim of evaluating organic species not yet studied in low temperature aqueous sulfuric acid.

  9. Correlations between optical, chemical and physical properties of biomass burn aerosols

    NASA Astrophysics Data System (ADS)

    Hopkins, R. J.; Lewis, K.; Desyaterik, Y.; Wang, Z.; Tivanski, A. V.; Arnott, W. P.; Laskin, A.; Gilles, M. K.

    2007-09-01

    Aerosols generated from burning different plant fuels were characterized to determine relationships between chemical, optical and physical properties. Single scattering albedo (ω) and Angstrom absorption coefficients (α ap) were measured using a photoacoustic technique combined with a reciprocal nephelometer. Carbon-to-oxygen atomic ratios, sp2 hybridization, elemental composition and morphology of individual particles were measured using scanning transmission X-ray microscopy coupled with near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS) and scanning electron microscopy with energy dispersion of X-rays (SEM/EDX). Particles were grouped into three categories based on sp2 hybridization and chemical composition. Measured ω (0.4 - 1.0 at 405 nm) and α ap (1.0 - 3.5) values displayed a fuel dependence. The category with sp2 hybridization >80% had values of ω (<0.5) and α ap (~1.25) characteristic of light absorbing soot. Other categories with lower sp2 hybridization (20 to 60%) exhibited higher ω (>0.8) and α ap (1.0 to 3.5) values, indicating increased absorption spectral selectivity.

  10. Physical characteristics of mouse sperm nuclei.

    PubMed Central

    Wyrobek, A J; Meistrich, M L; Furrer, R; Bruce, W R

    1976-01-01

    The nuclei of epididymal sperm, isolated from C57BL/6J and CBA/J inbred mice by their resistance to trypsin digestion, retain the shape differences of the intact sperm head. Various physical characteristics of these nuclei were measured and compared. The measurement of the projected dimensions of nuclei showed that the CBA nuclei are 13.5% longer than C57BL/6 nuclei (8.64 +/- 0.02 mum compared with 7.61 +/- 0.02 mum), 0.8% narrower (3.51 +/- 0.01 vs. 3.54 +/-0.01 mum) with 6.8% more area (22.34 +/- 0.10 vs. 20.91 +/- 0.09 mum2). However, the volumes of the nuclei as based on reconstructing calibrated electronmicrographs of serial sections of the nuclei indicated that CBA are about 7% smaller than C57BL/6 nuclei (3.72 +/- 0.08 vs. 4.01 +/- 0.03 mum3). The buoyant density of the CBA nuclei is 1.435 +/- 0.002 g/cm3 compared with 1.433 +/- 0.002 g/cm3 for the C57BL/6 nuclei as determined on linear CsCl and Renografin-76 density gradients and confirmed by a technique utilizing physiological tonicities. Therefore, the average mass of the CBA nuclei is less than that of the C57BL/6 nuclei (5.34 +/- 0.12 vs. 5.75 +/- 0.05 pg). The sedimentation velocities at unit gravity of nuclei from 11 inbred strains differ over a range of more than 6% with CBA nuclei sedimenting about 2.0% more slowly than C57BL/6 nuclei. We show that for these nuclei the sedimentation velocity can be related to their buoyant density, volume and a sedimentation shape factor. Within the errors of our measurements of these various characteristics, it was found that C57BL/6 and CBA nuclei have similar sedimentation shape factors. Therefore, the difference in sedimentation velocity between these nuclei appears to be primarily a result of differences in volume. The possible applications of these techniques to the physical separation of sperm are evaluated in the discussion. Images FIGURE 1 PMID:938720

  11. Physics of Stratocumulus Top (POST): turbulence characteristics

    NASA Astrophysics Data System (ADS)

    Jen-La Plante, Imai; Ma, Yongfeng; Nurowska, Katarzyna; Gerber, Hermann; Khelif, Djamal; Karpinska, Katarzyna; Kopec, Marta K.; Kumala, Wojciech; Malinowski, Szymon P.

    2016-08-01

    Turbulence observed during the Physics of Stratocumulus Top (POST) research campaign is analyzed. Using in-flight measurements of dynamic and thermodynamic variables at the interface between the stratocumulus cloud top and free troposphere, the cloud top region is classified into sublayers, and the thicknesses of these sublayers are estimated. The data are used to calculate turbulence characteristics, including the bulk Richardson number, mean-square velocity fluctuations, turbulence kinetic energy (TKE), TKE dissipation rate, and Corrsin, Ozmidov and Kolmogorov scales. A comparison of these properties among different sublayers indicates that the entrainment interfacial layer consists of two significantly different sublayers: the turbulent inversion sublayer (TISL) and the moist, yet hydrostatically stable, cloud top mixing sublayer (CTMSL). Both sublayers are marginally turbulent, i.e., the bulk Richardson number across the layers is critical. This means that turbulence is produced by shear and damped by buoyancy such that the sublayer thicknesses adapt to temperature and wind variations across them. Turbulence in both sublayers is anisotropic, with Corrsin and Ozmidov scales as small as ˜ 0.3 and ˜ 3 m in the TISL and CTMSL, respectively. These values are ˜ 60 and ˜ 15 times smaller than typical layer depths, indicating flattened large eddies and suggesting no direct mixing of cloud top and free-tropospheric air. Also, small scales of turbulence are different in sublayers as indicated by the corresponding values of Kolmogorov scales and buoyant and shear Reynolds numbers.

  12. a Study on the Physical and Chemical Properties of Stratospheric Aerosols.

    NASA Astrophysics Data System (ADS)

    Tabazadeh, Azadeh

    The physical and chemical properties of stratospheric aerosols under background and perturbed conditions are discussed. First, a multi-component aerosol physical chemistry model was developed to study the composition and reactivity of stratospheric aerosols. The compositions are predicted from an equilibrium assumption between the condensed-and gas-phases, and they are calculated as a function of ambient temperature, relative humidity, and the total mass of nitric acid and sulfuric acid present per unit volume of air. The water and solute activity parameters in the aerosol model are derived from various laboratory sources, and the set of equilibrium equations are solved using a unique numerical scheme. The aerosol model is applied to study the formation of nitric acid-containing aerosols in the stratosphere. Also, the equilibrium compositions are used to estimate the extent of aqueous phase processing of chlorine species in the aerosol solutions. This processing can contribute to the depletion of the stratospheric ozone layer, especially after major volcanic eruptions where sulfate aerosols are more abundant. Second, a surface chemistry model was constructed that includes Langmuir trace-gas adsorption and desorption, Brunauer, Emmett and Teller adsorption of water vapor, surface poisoning, solvation and diffusion of molecules on the surface, chemical activation and reaction of adsorbates, and product desorption or reaction. This model is used to study the effects of relative humidity and other physical parameters on the efficiency of heterogeneous chemical processes which occur on the surfaces of solid polar stratospheric clouds. These heterogeneous chemical processes are responsible for the formation of the "ozone hole", can contribute to global ozone depletion, and may have tropospheric significance. Finally, a fluid dynamics and thermodynamics model of volcanic eruption columns was used to develop a scheme for predicting the extent of HCl removal from volcanic

  13. Aerosol optical depth, physical properties and radiative forcing over the Arabian Sea

    NASA Astrophysics Data System (ADS)

    Satheesh, S. K.; Krishna Moorthy, K.; Kaufman, Y. J.; Takemura, T.

    2006-01-01

    The Arabian Sea region (4° N 20° N to 50° E 78° E) has a unique weather pattern on account of the Indian monsoon and the associated winds that reverse direction seasonally. The aerosol data, collected using ship-borne and island platforms (for 8 years from 1995 to 2002) along with MODIS (onboard TERRA satellite) data (from 2000 to 2003) have been used to evolve a comprehensive characterisation of the spatial and temporal variation in the physical, chemical, and radiative properties of aerosols over the Arabian Sea. The aerosol optical depth (AOD) was found to increase with latitude between the equator and 12° N. Over the northern Arabian Sea (regions lying north of 12° N), AODs do not show significant latitudinal variations; the average aerosol optical depth for this region was 0.29±0.12 during winter monsoon season (WMS; November to March) and 0.47±0.14 during summer monsoon season (SMS; April/May to September). The corresponding Angstrom exponents were 0.7±0.12 and 0.3±0.08, respectively. The low values of the exponent during SMS indicate the dominance of large aerosols (mainly dust particles >1 µm). The latitudinal gradient in AOD in the southern Arabian Sea is larger during SMS compared to WMS.

  14. Physicochemical and Toxicological Characteristics of Semi-volatile Components of Atmospheric Aerosols in an Urban Environment

    NASA Astrophysics Data System (ADS)

    Verma, V.; Pakbin, P.; Cheung, K. L.; Cho, A. K.; Schauer, J. J.; Shafer, M. M.; Kleinman, M. T.; Sioutas, C.

    2010-12-01

    Recent toxicological studies have confirmed the oxidative properties of atmospheric aerosols and their capability to generate reactive oxygen species (ROS) in biological systems (Chen and Lippmann, 2009). While the links between aerosol toxicity and refractory transition metals present in ambient particulate matter (PM) have been documented, there are limited studies investigating the oxidative characteristics of semi-volatile species. The goal of present study is to examine the contribution of semi-volatile compounds in the oxidative potential of atmospheric aerosols. Concentrated ambient and thermodenuded quasi-ultrafine particles (<180 nm) were collected using the versatile aerosol concentration enrichment system (VACES) at an urban site near downtown Los Angeles. A thermodenuder (TD) was used to selectively remove the semi-volatile components of these aerosols over the temperature range of 50-200 oC. The oxidative potential of PM was measured by means of the DTT (dithiothreitol) assay. Detailed chemical analyses of PM samples, including organic and elemental carbon, water soluble elements, inorganic ions and polycyclic aromatic hydrocarbons (PAHs), were conducted to quantify the volatility profiles of different PM species, and also to investigate their effect on the measured oxidative potential. Refractory constituents, such as metals and elemental carbon, were marginally affected by heating, while labile species such as organic carbon and PAHs showed progressive loss in concentration with increase in TD temperature. The DTT-measured oxidative potential of PM was significantly decreased as the aerosols were heated and their semi-volatile components were progressively removed (42 %, 47 % and 66 % decrease in DTT activity at 50, 100 and 200 oC, respectively). Regression analysis performed between chemical constituents and DTT activity showed that the oxidative potential was strongly correlated with organic carbon and PAHs (R≥0.80; p≤0.05). Thus, semi

  15. Remote continental aerosol characteristics in the Rocky Mountains of Colorado and Wyoming

    NASA Astrophysics Data System (ADS)

    Levin, Ezra J. T.

    The Rocky Mountains of Colorado and Wyoming enjoy some of the cleanest air in the United States, with few local sources of particulate matter or its precursors apart from fire emissions, windblown dust, and biogenic emissions. However, anthropogenic influences are also present with sources as diverse as the populated Front Range, large isolated power plants, agricultural emissions, and more recently emissions from increased oil and gas exploration and production. While long-term data exist on the bulk composition of background fine particulate matter at remote sites in the region, few long-term observations exist of aerosol size distributions, number concentrations and size resolved composition, although these characteristics are closely tied to important water resource issues through the potential aerosol impacts on clouds and precipitation. Recent modeling work suggests sensitivity of precipitation-producing systems to the availability of aerosols capable of serving as cloud condensation nuclei (CCN); however, model inputs for these aerosols are not well constrained due to the scarcity of data. In this work I present aerosol number and volume concentrations, size distributions, chemical composition and hygroscopicity measurements from long-term field campaigns. I also explore the volatility of organic material from biomass burning and the potential impacts on aerosol loading. Relevant aerosol observations were obtained in several long-term field studies: the Rocky Mountain Atmospheric Nitrogen and Sulfur study (RoMANS, Colorado), the Grand Tetons Reactive Nitrogen Deposition Study (GrandTReNDS, Wyoming) and as part of the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen project (BEACHON, Colorado). Average number concentrations (0.04 < Dp < 20 mum) measured during the field studies ranged between 1000 -- 2000 cm-3 during the summer months and decreased to 200 -- 500 cm-3 during the winter. These seasonal changes in aerosol

  16. Determination of Atmospheric Aerosol Characteristics from the Polarization of Scattered Radiation

    NASA Technical Reports Server (NTRS)

    McCormick, M. P.; Harris, F. S., Jr.

    1973-01-01

    Aerosols affect the polarization of radiation in scattering, hence measured polarization can be used to infer the nature of the particles. Size distribution, particle shape, real and absorption parts of the complex refractive index affect the scattering. From Lorenz-Mie calculations of the 4-Stokes parameters as a function of scattering angle for various wavelengths the following polarization parameters were plotted: total intensity, intensity of polarization in plane of observation, intensity perpendicular to the plane of observation, polarization ratio, polarization (using all 4-Stokes parameters), plane of the polarization ellipse and its ellipticity. A six-component log-Gaussian size distribution model was used to study the effects of the nature of the polarization due to variations in the size distribution and complex refractive index. Though a rigorous inversion from measurements of scattering to detailed specification of aerosol characteristics is not possible, considerable information about the nature of the aerosols can be obtained. Only single scattering from aerosols was used in this paper. Also, the background due to Rayleigh gas scattering, the reduction of effects as a result of multiple scattering and polarization effects of possible ground background (airborne platforms) were not included.

  17. Pesticide aerosol characteristics in the vicinity of an agricultural vehicle cab during application.

    PubMed

    Bémer, Denis; Fismes, Joelle; Subra, Isabelle; Blachère, Veronique; Protois, Jean-Claude

    2007-07-01

    Pesticide spraying for crop protection leads to the formation of a mist of droplets, part of which is dispersed into the atmosphere. The characteristics of this aerosol, namely its particle size distribution and concentration, were measured during five campaigns involving cereal crop growing, wine grape culture, and orcharding. The measurement method incorporated a tracer product (fluorescein) with the treatment product; the pesticide aerosol concentration was then deduced from the tracer concentration. This method was validated by comparing the pesticide concentration determined by tracing with the concentration determined by direct measurement of the active substance of the pesticide. Concentration was measured using sampling filters, and particle size distribution was measured using cascade impactors. Instruments were mounted on an agricultural vehicle cab to optimize aerosol characterization, and then the cab's confinement efficiency was determined. Aerosols analyzed were fine, featuring mass median diameters between 4 microm and 15 microm; they are therefore highly dispersive. Their concentration is sufficiently high to justify operator protection by an efficient, filtered-air, pressurized cab, especially in wine grape culture and orcharding, which are the sectors where the highest pesticide transfers have been observed. PMID:17487720

  18. Statistical Characteristics of Aerosol Extinction Coefficient Profile in East Asia from CALIPSO

    NASA Astrophysics Data System (ADS)

    Sun, Xuejin; Zhou, Junhao; Zhou, Yongbo

    2016-06-01

    Aerosol extinction coefficient profile (ECP) is important in radiative transfer modeling, however, knowledge of ECP in some area has not been clearly recognized. To get a full understanding of statistical characteristics of ECP in three Asian regions: the Mongolian Plateau, the North China Plain and the Yellow Sea, CALIPSO aerosol product in 2012 is processed by conventional statistical methods. Orbit averaged ECP turns out to be mainly exponential and Gaussian patterns. Curve fitting shows that the two ECP patterns account for more than 50 percent of all the samples, especially in the Yellow Sea where the frequency of occurrence even reaches over 80 percent. Parameters determining fitting curves are provided consequently. To be specific, Gaussian pattern is the main ECP distribution in the Mongolian Plateau and the Yellow Sea, and exponential pattern predominates in the North China Plain. Besides, aerosol scale height reaches its maximum in summer and in the Mongolian Plateau. Meanwhile, the uplifting and deposition of dust during transportation are potentially explanations to the occurrence of Gaussian ECP. The results have certain representativeness, and contribute to reducing uncertainties of aerosol model in relevant researches.

  19. Measurements of physical and chemical properties of urban aerosols and their CCN activities in Seoul during the KORUS-AQ pre-campaign

    NASA Astrophysics Data System (ADS)

    Kim, N.; Yum, S. S.; Park, M.; Shin, H. J.; Bae, G. N.; Kwak, K. H.; Park, J. S.; Park, S. M.; Ahn, J.

    2015-12-01

    Interest in cloud condensation nuclei (CCN) has been increasing for the last few decades due to their first order effects on radiative and microphysical properties of clouds. Particularly, scientific understanding of CCN from anthropogenic sources becomes important because it is now considered that large uncertainties in climate change predictions stem from insufficient understanding of CCN. CCN activity is influenced by size and chemical component of aerosols. The KORUS-AQ campaign, jointly organized by National Institute of Environmental Research (NIER) of Korea and National Aeronautics and Space Administration (NASA) aims at understanding various aspects of air quality problem in Korea and will be held in spring, 2016. In preparation for this campaign, pre-campaign was held during May 18-June 13, 2015, in Seoul where numerous local anthropogenic sources exist and influence of Chinese continental outflow directly affects. Here we present some of the important results from the pre-campaign. Chemical properties of aerosols were measured with AMS. Aerosol and CCN number concentrations, aerosol size distribution and aerosol hygroscopic growth factor were measured by CPC, CCN counter, SMPS and H-TDMA, respectively. Average diurnal variation of aerosol number concentration showed three dominant peaks at around 0600_UTC and morning and evening rush hours. Each peak seemed to have different characteristics and therefore detailed analyses of physical and chemical properties of aerosols during the peaks as well as during some special events will be made. The hygroscopicity parameter, kappa, will be estimated by examining CCN activity, H-TDMA measured hygroscopic growth factor and mixing rule of aerosol chemical components, and the result will be compared as well.

  20. In situ observations of aerosol physical and optical properties in northern India

    NASA Astrophysics Data System (ADS)

    Lihavainen, H.; Hyvarinen, A.; Hooda, R. K.; Raatikainen, T. E.; Sharma, V.; Komppula, M.

    2012-12-01

    The southern Asia, including India, is exposed to substantial quantities of particulate air pollution originating mainly from fossil fuel combustion and biomass burning. Besides serious adverse health effects, these aerosols cause a large reduction of solar radiation at the surface accompanied by a substantial atmospheric heating, which is expected to have significant influences on the air temperature, crop yields, livestock and water resources over the southern Asia. The various influences by aerosols in this region depend crucially on the development of aerosol emissions from household, industrial, transportation and biomass burning sectors. The main purpose of this study is to investigate several measured aerosol optical and physical properties. We take advantage of observations from two measurement stations which have been established by the Finnish Meteorological Institute and The Energy and Resources Institute. Another station is on the foothills of Himalayas, in Mukteshwar, about 350 km east of New Delhi at elevation about 2 km ASL. This site is considered as a rural background site. Measurements of aerosol size distribution (7-500 nm), PM10, PM2.5, aerosol scattering and absorption coefficients and weather parameters have been conducted since 2006. Another station is located at the outskirts of New Delhi, in Gual Pahari, about 35 km south of city centre. It is considered as an urban background site. Measurements of aerosol size distribution (7 nm- 10 μm), PM10, PM2.5, aerosol scattering and absorption coefficients, aerosol optical depth, aerosol vertical distribution (LIDAR), aerosol filter sampling for chemical characterization and weather parameters were conducted between 2008 and 2010. On the overall average PM10 and PM2.5 values were about 3-4 times higher in Gual Pahari than in Mukteshwar as expected, 216 and 126 μg m^-3, respectively. However, difference depended much on the season, so that during winter time PM10 and PM2.5 concentrations were about

  1. PHYSICAL AND CHEMICAL CHARACTERIZATION OF INDOOR AEROSOLS RESULTING FROM THE USE OF TAP WATER IN PORTABLE HOME HUMIDIFIERS

    EPA Science Inventory

    An indoor air quality study was conducted in Boise, ID, residences to evaluate the range of aerosol concentrations that result from using tap water in portable home humidifiers and to characterize the physical and chemical properties of the humidifier aerosol. M10 concentrations ...

  2. Composition and physical properties of the Asian Tropopause Aerosol Layer and the North American Tropospheric Aerosol Layer

    PubMed Central

    Yu, Pengfei; Toon, Owen B; Neely, Ryan R; Martinsson, Bengt G; Brenninkmeijer, Carl A M

    2015-01-01

    Recent studies revealed layers of enhanced aerosol scattering in the upper troposphere and lower stratosphere over Asia (Asian Tropopause Aerosol Layer (ATAL)) and North America (North American Tropospheric Aerosol Layer (NATAL)). We use a sectional aerosol model (Community Aerosol and Radiation Model for Atmospheres (CARMA)) coupled with the Community Earth System Model version 1 (CESM1) to explore the composition and optical properties of these aerosol layers. The observed aerosol extinction enhancement is reproduced by CESM1/CARMA. Both model and observations indicate a strong gradient of the sulfur-to-carbon ratio from Europe to the Asia on constant pressure surfaces. We found that the ATAL is mostly composed of sulfates, surface-emitted organics, and secondary organics; the NATAL is mostly composed of sulfates and secondary organics. The model also suggests that emission increases in Asia between 2000 and 2010 led to an increase of aerosol optical depth of the ATAL by 0.002 on average which is consistent with observations. Key Points The Asian Tropopause Aerosol Layer is composed of sulfate, primary organics, and secondary organics The North American Tropospheric Aerosol Layer is mostly composed of sulfate and secondary organics Aerosol Optical Depth of Asian Tropopause Aerosol Layer increases by 0.002 from 2000 to 2010 PMID:26709320

  3. In situ real-time measurement of physical characteristics of airborne bacterial particles

    NASA Astrophysics Data System (ADS)

    Jung, Jae Hee; Lee, Jung Eun

    2013-12-01

    Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis.

  4. The Characteristics of Long-range Transboundary Inorganic Secondary Aerosols in Northeast Asia

    NASA Astrophysics Data System (ADS)

    Kim, Y. J.; Carmichael, G. R.; Woo, J. H.; Qiang, Z.

    2014-12-01

    Recurrent particle matter episodes greatly influence air quality in Northeast Asia. According to many studies, a major reason is long-range transport of air pollutant. Large amount of emission of chemical compounds aggravate air pollution in the region. Emitted air pollutants mainly come from industrialized regions along the East China coast. It can be transported over downwind region by the prevailing westerlies. The long-rang transported fine particle certainly attributes to air quality in downwind region, but there are many unknowns on the quantity, transport pattern, and secondary aerosol production mechanism despite the fact with many studies have been performed. Major contributors of PM2.5 are inorganic secondary aerosols, sulfate, nitrate and ammonium, in Korea. Especially high relative contributions of inorganic secondary aerosols appear for westerly wind cases. The main pathway of production of inorganic secondary aerosols is produced by converting from SO2 and NOx during the long-range transport but the contribution varies dramatically depending on season and wind pattern. Sulfate is consistently the primary contributor of PM2.5 still now but we should more concern nitrate because that NOx emissions of China is increasing steeply since 2000 by leading powerplant, industry, and transport, despite downward trend of SO2. In order to better understand regional air quality modeling of the long-range transport, international study, MICS-Asia phase III, has been initiated with many researchers. We will present chemical characteristics of PM2.5 long-range transport during westerly wind cases focused on secondary aerosol, tracking their transport pattern, and production pathway. Results using CMAQ with the modeling domain covering Northeast and Southeast China, Korea, and Japan with 15km resolution will be discussed.

  5. Characteristics of aerosols in urban and rural areas: GEOS-Chem+APM nested grid simulation and comparison with observations

    NASA Astrophysics Data System (ADS)

    Luo, G.; Yu, F.

    2011-12-01

    Aerosol microphysics (nucleation, condensation, growth and coagulation) shows significant impact on aerosol size distribution which is important for the investigation of aerosol properties and its associated environment and climate impacts. Here, we use a recently developed global size-resolved aerosol microphysics model (GEOS-Chem+APM, Yu and Luo, ACP, 2009), which uses the ion-mediated nucleation theory to simulate tropospheric particle formation and a new scheme to consider the kinetic condensation of low volatile secondary organic gas (SOG) (in addition to H2SO4 gas) on nucleated particles, to study the major characteristics of aerosol size distribution in urban and rural areas and explore the key factors dominating aerosol properties over these regions. Multiple-year simulations with a nested domain (horizontal resolution 0.5ox0.667o) over Europe have been carried out and compared with long-term continuous particle size distribution measurements at an urban area (Melpitz, Gernmay) and a rural area (Hyytiälä, Finland). The analysis shows that aerosol number concentration at the urban site is generally three times higher than that at the rural site. Significant diurnal and inter-monthly variations of aerosol nucleation events can be found at both sites. Because of high concentration of sulfur acid, freshly nucleated particles at urban site are much easier to grow to large-size particles rather than those at rural site. The model captures the major characteristics of aerosol size distribution observed at the two sites. Model simulation implicates that sulfur acid dominates particle growth process at Melpitz, while SOG shows significant contribution at Hyytiälä, especially during summertime. We also study the mixing state of aerosols at both the urban and rural sites, and aerosol optical property and radiative forcing in urban and rural areas are calculated to investigate the associated environment and climate impacts over these regions.

  6. Optical, physical, and chemical properties of springtime aerosol over Barrow Alaska in 2008

    SciTech Connect

    Shantz, Nicole C.; Gultepe, Ismail; Andrews, Elisabeth; Earle, Michael; MacDonald, A. M.; Liu, Peter S.K.; Leaitch, W. R.

    2014-03-06

    Airborne observations from four flights during the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) are used to examine some cloud-free optical, physical, and chemical properties of aerosol particles in the springtime Arctic troposphere. The number concentrations of particles larger than 0.12 μm (Na>120), important for light extinction and cloud droplet formation, ranged from 15 to 2260 cm-3, with the higher Na>120 cases dominated by measurements from two flights of long-range transported biomass burning (BB) aerosols. The two other flights examined here document a relatively clean aerosol and an Arctic Haze aerosol impacted by larger particles largely composed of dust. For observations from the cleaner case and the BB cases, the particle light scattering coefficients at low relative humidity (RH<20%) increased nonlinearly with increasing Na>120, driven mostly by an increase in mean sizes of particles with increasing Na>120 (BB cases). For those three cases, particle light absorption coefficients also increased nonlinearly with increasing Na>120 and linearly with increasing submicron particle volume concentration. In addition to black carbon, brown carbon was estimated to have increased light absorption coefficients by 27% (450 nm wavelength) and 14% (550 nm) in the BB cases. For the case with strong dust influence, the absorption relative to submicron particle volume was small compared with the other cases. There was a slight gradient of Passive Cavity Aerosol Spectrometer Probe (PCASP) mean volume diameter (MVD) towards smaller sizes with increasing height, which suggests more scavenging of the more elevated particles, consistent with a typically longer lifetime of particles higher in the atmosphere. However, in approximately 10% of the cases, the MVD increased (>0.4 μm) with increasing altitude, suggesting transport of larger fine particle mass (possibly coarse particle mass) at high levels over the Arctic. This may be because of transport of

  7. Aerosol and nucleation research in support of NASA cloud physics experiments in space. [ice nuclei generator for the atmospheric cloud physics laboratory on Spacelab

    NASA Technical Reports Server (NTRS)

    Vali, G.; Rogers, D.; Gordon, G.; Saunders, C. P. R.; Reischel, M.; Black, R.

    1978-01-01

    Tasks performed in the development of an ice nucleus generator which, within the facility concept of the ACPL, would provide a test aerosol suitable for a large number and variety of potential experiments are described. The impact of Atmospheric Cloud Physics Laboratory scientific functional requirements on ice nuclei generation and characterization subsystems was established. Potential aerosol generating systems were evaluated with special emphasis on reliability, repeatability and general suitability for application in Spacelab. Possible contamination problems associated with aerosol generation techniques were examined. The ice nucleating abilities of candidate test aerosols were examined and the possible impact of impurities on the nucleating abilities of those aerosols were assessed as well as the relative merits of various methods of aerosol size and number density measurements.

  8. Modeling Gas-Particle Partitioning of SOA: Effects of Aerosol Physical State and RH

    NASA Astrophysics Data System (ADS)

    Zuend, A.; Seinfeld, J.

    2011-12-01

    Aged tropospheric aerosol particles contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. In liquid aerosol particles non-ideal mixing of all species determines whether the condensed phase undergoes liquid-liquid phase separation or whether it is stable in a single mixed phase, and whether it contains solid salts in equilibrium with their saturated solution. The extended thermodynamic model AIOMFAC is able to predict such phase states by representing the variety of organic components using functional groups within a group-contribution concept. The number and composition of different condensed phases impacts the diversity of reaction media for multiphase chemistry and the gas-particle partitioning of semivolatile species. Recent studies show that under certain conditions biogenic and other organic-rich particles can be present in a highly viscous, semisolid or amorphous solid physical state, with consequences regarding reaction kinetics and mass transfer limitations. We present results of new gas-particle partitioning computations for aerosol chamber data using a model based on AIOMFAC activity coefficients and state-of-the-art vapor pressure estimation methods. Different environmental conditions in terms of temperature, relative humidity (RH), salt content, amount of precursor VOCs, and physical state of the particles are considered. We show how modifications of absorptive and adsorptive gas-particle mass transfer affects the total aerosol mass in the calculations and how the results of these modeling approaches compare to data of aerosol chamber experiments, such as alpha-pinene oxidation SOA. For a condensed phase in a mixed liquid state containing ammonium sulfate, the model predicts liquid-liquid phase separation up to high RH in case of, on average, moderately hydrophilic organic compounds, such as first generation oxidation products of alpha-pinene. The computations also reveal that treating liquid phases as ideal

  9. Aerosol Physical, Optical and Chemical Properties during African Dust Events at Cape San Juan (CPR)

    NASA Astrophysics Data System (ADS)

    Reyes de Jongh, C.; Mayol Bracero, O. L.; Rivera Vazquez, H.; Sheridan, P.; Ogren, J. A.

    2008-12-01

    Large amounts of atmospheric dust are lifted from the North African deserts and are transported by the trade winds over the Caribbean region, especially during the summer months. How African dust particles influence the earth's radiative budget is not well understood because these particles are highly variable and their physical, optical, and chemical properties are poorly characterized, especially when they are atmospherically processed as are those that travel from Africa to the Caribbean region. Here we present results of aerosol measurements performed at Cape San Juan (CPR), a ground-based station located at the northeastern tip of the Caribbean island of Puerto Rico. We used a condensation particle counter to determine the particle number concentration, a sunphotometer (part of the AErosol RObotical NETwork, AERONET, aeronet.gsfc.nasa.gov) to determine volume size distributions and aerosol optical thickness, and a 3-wavelength nephelometer and particle/soot absorption photometer to determine the scattering and absorption coefficients. Filter samples for chemical analyses were collected with stacked-filter units. Preliminary results show that African dust air masses have higher average particle number concentrations (N=720 cm -3 ), aerosol optical depth (AOD = 0.27), and scattering and absorption coefficients (σ s = 30 Mm -1 , σ a = 0.46 Mm -1 ) than clean air masses (N = 460 cm -3 , AOD= 0.08, σ s = 11 Mm -1 , σ a = 0.37 Mm -1 . Results presented will also show how changes in aerosol optical properties in the presence and absence of African dust relate to the physical and chemical composition of the particles.

  10. Comparing Organic Aerosol Composition from Marine Biogenic Sources to Seawater and to Physical Sea Spray Models

    NASA Astrophysics Data System (ADS)

    Russell, L. M.; Frossard, A. A.; Sanchez, K.; Massoli, P.; Elliott, S.; Burrows, S. M.; Bates, T. S.; Quinn, P.

    2015-12-01

    In much of the marine atmosphere, organic components in aerosol particles have many sources other than sea spray that contribute organic constituents. For this reason, physical sea spray models provide an important technique for studying the organic composition of particles from marine biogenic sources. The organic composition of particles produced by two different physical sea spray models were measured in three open ocean seawater types: (i) Coastal California in the northeastern Pacific, which is influenced by wind-driven, large-scale upwelling leading to productive or eutrophic (nutrient-rich) seawater and high chl-a concentrations, (ii) George's Bank in the northwestern Atlantic, which is also influenced by nutrient upwelling and eutrophic seawater with phytoplankton productivity and high chl-a concentrations, and (iii) the Sargasso Sea in the subtropical western Atlantic, which is oligotrophic and nutrient-limited, reflected in low phytoplankton productivity and low chl-a concentrations. Fourier transform infrared spectroscopy provides information about the functional group composition that represents the marine organic fraction more completely than is possible with techniques that measure non-refractory mass (vaporizable at 650°C). After separating biogenic marine particles from those from other sources, the measured compositions of atmospheric marine aerosol particles from three ocean regions is 65±12% hydroxyl, 21±9% alkane, 6±6% amine, and 7±8% carboxylic acid functional groups. The organic composition of atmospheric primary marine (ocean-derived) aerosol particles is nearly identical to model generated primary marine aerosol particles from bubbled seawater. Variability in productive and non-productive seawater may be caused by the presence of surfactants that can stabilize the bubble film and lead to preferential drainage of the more soluble (lower alkane group fraction) organic components without substantial changes in overall group composition

  11. Absorption characteristics of aerosols over the northwestern region of India: Distinct seasonal signatures of biomass burning aerosols and mineral dust

    NASA Astrophysics Data System (ADS)

    Gogoi, Mukunda M.; Suresh Babu, S.; Krishna Moorthy, K.; Manoj, M. R.; Chaubey, Jai Prakash

    2013-07-01

    Continuous measurements of aerosol black carbon (BC) mass concentrations made over a period of 3 years from a semi-arid, near-coastal, remote and sparsely inhabited location along with satellite-based data of aerosol absorption index, optical depth and extinction profiles in western India are used to characterize the distinct nature of aerosols near the surface and in the free troposphere and their seasonality. Despite being far remote and sparsely inhabited, significant levels of BC are observed in the ambient during winter (1.45 ± 0.71 μg m-3) attributed to biomass burning aerosols, advected to the site from the north and west; while during summer the concentrations are far reduced (0.23 ± 0.11 μg m-3) and represent the apparent background concentrations. The spectral absorption coefficients suggest the BC during summer be mostly of fossil fuel combustions. The strong convective boundary layer dynamics produces significant diurnal variation during winter and modulates to a lesser extent the seasonal variation. Examination of aerosol (absorption) index from OMI data for the study period showed a seasonal pattern that is almost opposite to that seen at the surface; with high aerosol index in summer, showing a significant difference between the surface and columnar aerosol types in summer. MISR and MODIS-derived columnar AOD follow the OMI pattern. Analysis of the vertical profiles of aerosol extinction and volume depolarization ratio (VDR), derived from CALIPSO data indicates the presence of strong dust layers with VDR ˜ 0.3 in the altitude region 4-6 km, contributing to the high aerosol index in the OMI data, while the surface measurements show absorptive properties representing fossil fuel BC aerosols.

  12. Identification of characteristic mass spectrometric markers for primary biological aerosol particles and comparison with field data from submicron pristine aerosol particles

    NASA Astrophysics Data System (ADS)

    Freutel, F.; Schneider, J.; Zorn, S. R.; Drewnick, F.; Borrmann, S.; Hoffmann, T.; Martin, S. T.

    2009-04-01

    The contribution of primary biological aerosol (PBA) to the total aerosol particle concentration is estimated to range between 25 and 80%, depending on location and season. Especially in the tropical rain forest it is expected that PBA is a major source of particles in the supermicron range, and is also an important fraction of the submicron aerosol. PBA particles like plant fragments, pollen, spores, fungi, viruses etc. contain chemical compounds as proteins, sugars, amino acids, chlorophyll, and cellular material as cellulose. For this reason we have performed mass spectrometric laboratory measurements (Aerodyne C-ToF and W-ToF AMS, single particle laser ablation instrument SPLAT) on pure submicron aerosol particles containing typical PBA compounds in order to identify typical mass spectral patterns of these compounds and to explain the observed fragmentation patterns on the basis of molecular structures. These laboratory data were compared to submicron particle mass spectra obtained during AMAZE-08 (Amazonian Aerosol CharacteriZation Experiment, Brazil, February/March 2008). The results indicate that characteristic m/z ratios for carbohydrates (e.g., glucose, saccharose, levoglucosan, mannitol) can be identified, for example m/z = 60(C2H4O2+) or m/z = 61(C2H5O2+). Certain characteristic peaks for amino acids were also identified in the laboratory experiments. In the field data from AMAZE-08, these characteristic peaks for carbohydrates and amino acids were found, and their contribution to the total organic mass was estimated to about 5%. Fragment ions from peptides and small proteins were also identified in laboratory experiments. Larger proteins, however, seem to become oxidized to CO2+ to a large extend in the vaporizing process of the AMS. Thus, detection of proteins in atmospheric aerosol particles with the AMS appears to be difficult.

  13. Physics Teacher Characteristics and Classroom Practices

    NASA Astrophysics Data System (ADS)

    Taylor, Melissa S.; Phillips, Jeffrey A.

    2010-10-01

    One hundred eighteen high school and college teachers in Southern California completed a web-based survey designed to better understand the differences in physics classrooms and the reasons behind the teachers' choices. Survey topics included teachers' familiarity and use of research-based instructional strategies, amount of student-student interaction in their classes, their views about teaching and their interactions with the physics teaching community. Partial results from the survey are presented in this paper. Among the findings was that while increased interactions with colleagues correlated with more student-student interactions, increased participation in conferences or reading of journals related to physics teaching did not.

  14. On the physics, chemistry and toxicology of ultrafine anthropogenic, atmospheric aerosols (UAAA): new advances.

    PubMed

    Spurny, K R

    1998-08-01

    The existing data about the epidemiology, toxicology, physics and chemistry of atmospheric particulate pollutants were recently essentially completed and extended. They do support the hypothesis that the fine and very fine dispersed fraction of the atmospheric anthropogenic aerosols (UAAA) are responsible for the aggravation of the health risk potential of the polluted atmosphere during the last decade. The recently published data dealing primarily with the physics, chemistry, sampling and analysis of these highly dispersed particulate air pollutants are reviewed, summarized and critically evaluated. PMID:9820675

  15. Aerosol and Cloud Microphysical Characteristics of Rifts and Gradients in Maritime Stratocumulus Clouds

    NASA Technical Reports Server (NTRS)

    Sharon, Tarah M.; Albrecht, Bruce A.; Jonsson, Haflidi H.; Minnis, Patrick; Khaiyer, Mandana M.; Van Reken, Timothy; Seinfeld, John; Flagan, Rick

    2008-01-01

    A cloud rift is characterized as a large-scale, persistent area of broken, low reflectivity stratocumulus clouds usually surrounded by a solid deck of stratocumulus. A rift observed off the coast of Monterey Bay, California on 16 July 1999 was studied to compare the aerosol and cloud microphysical properties in the rift with those of the surrounding solid stratus deck. Variables measured from an instrumented aircraft included temperature, water vapor, and cloud liquid water. These measurements characterized the thermodynamic properties of the solid deck and rift areas. Microphysical measurements made included aerosol, cloud drop and drizzle drop concentrations and cloud condensation nuclei (CCN) concentrations. The microphysical characteristics in a solid stratus deck differ substantially from those of a broken, cellular rift where cloud droplet concentrations are a factor of 2 lower than those in the solid cloud. Further, CCN concentrations were found to be about 3 times greater in the solid cloud area compared with those in the rift and aerosol concentrations showed a similar difference as well. Although drizzle was observed near cloud top in parts of the solid stratus cloud, the largest drizzle rates were associated with the broken clouds within the rift area. In addition to marked differences in particle concentrations, evidence of a mesoscale circulation near the solid cloud rift boundary is presented. This mesoscale circulation provides a mechanism for maintaining a rift, but further study is required to understand the initiation of a rift and the conditions that may cause it to fill.

  16. Contribution of long-range transported aerosols to aerosol optical and physical properties: 3-year measurements at Gosan, Korea

    NASA Astrophysics Data System (ADS)

    Heo, J.; Kim, S. W.; Kim, J. H.; Ogren, J. A.; Yoon, S. C.

    2015-12-01

    Recently, more attentions have been paid to air quality in East Asia due to the enhanced loading of atmospheric pollutants related to rapid industrialization. Gosan Climate Observatory (GCO), Korea is regarded as an ideal site to study the transport of atmospheric pollutants because it is frequently influenced by various airmasses from China, Korea, Japan and Pacific Ocean. In order to understand aerosol optical and physical properties according to airmass transport routes, three-year (2012-2014) continuous measurements of aerosol scattering/absorption coefficient and number size distribution were analyzed, together with 48-hour backward trajectory calculations. The averaged aerosol absorption (σa) and scattering coefficient (σs) for airmasses transported from North China (NC; 36% of all trajectories) were 6.65 Mm-1 and 94.72 Mm-1 at 550 nm wavelength, respectively, which were similar to those for stagnant airmasses (ST; 22% of all trajectories; σa: 6.26 Mm-1, σs: 93.99 Mm-1). The highest values of σa (7.03 Mm-1) and σs (108.34 Mm-1) were observed when airmasses were traveled from South China (SC; 11% of all trajectories). σa and σs for airmasses from Korean Peninsula (KP; 7% of all trajectories) and Pacific Ocean (PO; 14% of all trajectories; in parenthesis) were 5.63 (2.76) Mm-1 and 73.63 (50.93) Mm-1, respectively. Compared to other airmasses, the higher values of Scattering Angstrom Exponent (SAE) for ST (1.65) is thought to be the build-up of anthropogenic fine particulate pollutants. The Absorption Angstrom Exponent (AAE) was estimated to be 1.32 for NC airmass and 1.02 for SC airmass. Over the study period, 130 days of total 557 days were identified as new particle formation and growth event (NPF) from Scanning Mobility Particle Sizer (SMPS) measurements by Cyclostationary Empirical Orthogonal Function (CSEOF) approach. Especially, 55.4% (72 days) of total 130 NPF days were found when a cold and dry airmass comes from NC after passing the frontal

  17. Vertical distribution of optical and micro-physical properties of ambient aerosols during dry haze periods in Shanghai

    NASA Astrophysics Data System (ADS)

    Chen, Yonghang; Liu, Qiong; Geng, Fuhai; Zhang, Hua; Cai, Changjie; Xu, Tingting; Ma, Xiaojun; Li, Hao

    2012-04-01

    Based on the lidar data obtained from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite of NASA (National Aeronautics and Space Administration), the vertical distributions of aerosols are revealed during dry haze periods in the Shanghai vicinity by analyzing the optical and micro-physical parameters including total attenuated backscatter coefficient (TABC), volume depolarization ratio (VDR) and total attenuated color ratio (TACR). The preliminary conclusion is that when dry haze occurs in the Shanghai vicinity, smoke and maritime aerosols are the major types in summer and autumn and aerosols might be affected by long-distance transport of dust in spring; lower troposphere below 2 km is the layer polluted most severely and aerosol scattering with relatively irregular shape is much stronger than that of aerosols with relatively regular shape within 2-10 km in middle and upper troposphere; relatively large aerosols appear more frequently in lower (0-2 km) and middle troposphere (2-6 km) than those in upper troposphere (6-10 km). In addition, HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model is applied to analyze the aerosol sources during two typical episodes. The results indicate that the middle and upper troposphere in the Shanghai vicinity are affected by the long-distance transport of dusts from northwest of China or other upstream regions. The high aerosol concentrations in the Shanghai vicinity are mainly caused not only by local human activities but also by the long-distance transport from other places.

  18. Emissions and Characteristics of Ice Nucleating Particles Associated with Laboratory Generated Nascent Sea Spray Aerosol

    NASA Astrophysics Data System (ADS)

    McCluskey, C. S.; Hill, T. C. J.; Beall, C.; Sultana, C. M.; Moore, K.; Cornwell, G.; Lee, C.; Al-Mashat, H.; Laskina, O.; Trueblood, J.; Grassian, V. H.; Prather, K. A.; Kreidenweis, S. M.; DeMott, P. J.

    2015-12-01

    Accurate emission rates and activity spectra of atmospheric ice nucleating particles (INPs) are required for proper representation of aerosol-cloud interactions in atmospheric modeling studies. However, few investigations have quantified or characterized oceanic INP emissions. In conjunction with the Center for Aerosol Impacts on the Climate and the Environment, we have directly measured changes in INP emissions and properties of INPs from nascent sea spray aerosol (SSA) through the evolution of phytoplankton blooms. Multiple offline and online instruments were used to monitor aerosol chemistry and size, and bulk water characteristics during two phytoplankton bloom experiments. Two methods were utilized to monitor the number concentrations of INPs from 0 to -34 °C: The online CSU continuous flow diffusion chamber (CFDC) and collections processed offline using the CSU ice spectrometer. Single particle analyses were performed on ice crystal residuals downstream of the CFDC, presumed to be INPs, via scanning transmission electron microscopy (STEM) and Raman microspectroscopy. Preliminary results indicate that laboratory-generated nascent SSA corresponds to number concentrations of INPs that are generally consistent with open ocean regions, based on current knowledge. STEM analyses revealed that the sizes of ice crystal residuals that were associated with nascent SSA ranged from 0.3 to 2.5 μm. Raman microspectroscopy analysis of 1 μm sized residuals found a variety of INP identities, including long chain organics, diatom fragments and polysaccharides. Our data suggest that biological processes play a significant role in ocean INP emissions by generating the species and compounds that were identified during these studies.

  19. Characteristics of aerosol pollution during heavy haze events in Suzhou, China

    NASA Astrophysics Data System (ADS)

    Tian, M.; Wang, H. B.; Chen, Y.; Yang, F. M.; Zhang, X. H.; Zou, Q.; Zhang, R. Q.; Ma, Y. L.; He, K. B.

    2015-11-01

    A comprehensive measurement was carried out to analyze the heavy haze events in Suzhou in January 2013 when extremely severe haze pollution occurred in many cities in China especially in the East. Hourly concentrations of PM2.5, chemical composition (including water-soluble inorganic ions, OC, and EC), and gas-phase precursors were obtained via on-line monitoring system. Based on these data, detailed aerosol composition, light extinction and gas-phase precursors were analyzed to understand the characteristics of the haze events, moreover, the formation mechanism of nitrate and sulfate in PM2.5 and the regional sources deduced from trajectory and PSCF were discussed to explore the origin of the heavy aerosol pollution. The results showed that frequent haze events were occurred on January 2013 and the concentrations of PM2.5 often exceeded 150 μg m-3 during the haze occurrence, with a maximum concentration of 324 μg m-3 on 14 January 2013. Unfavorable weather conditions (high RH, and low rainfall, wind speed and atmospheric pressure), high concentration of secondary aerosol species (including SO42-, NO3-, NH4+, and SOC) and precursors were observed during the haze events. Additionally, OM, (NH4)2SO4, NH4NO3 were demonstrated to be the major contributors to the visibility impairment but the share differed from haze events. This study also found that the high concentration of sulfate might be explained by the heterogeneous reactions in the aqueous surface layer of pre-existing particles or in cloud processes while nitrate might be mainly formed through homogeneous gas-phase reactions. The results of trajectory clustering and the PSCF method manifested that aerosol pollutions in the studied areas were mainly affected by local activities and surrounding sources transported from nearby cities.

  20. Chemical and Physical Properties of Bulk Aerosols within Four Sectors Observed during TRACE-P

    NASA Technical Reports Server (NTRS)

    Jordan, C. E.; Anderson, B. E.; Talbot, R. W.; Dibb, J. E.; Fuelberg, E.; Hudgins, C. H.; Kiley, C. M.; Russo, R.; Scheuer, E.; Seid, G.

    2003-01-01

    Chemical and physical aerosol data collected on the DC-8 during TRACE-P were grouped into four sectors based on back trajectories. The four sectors represent long-range transport from the west (WSW), regional circulation over the western Pacific and Southeast Asia (SE Asia), polluted transport from Northern Asia with substantial sea salt at low altitudes (NNW) and a substantial amount of dust (Channel). WSW has generally low mixing ratios at both middle and high altitudes, with the bulk of the aerosol mass due to non-sea-salt water-soluble inorganic species. Low altitude SE Asia also has low mean mixing ratios in general, with the majority of the aerosol mass comprised of non-sea-salts, however, soot is also relatively important m this region. "w had the highest mean sea salt mixing ratios, with the aerosol mass at low altitudes (a km) evenly divided between sea salts, mm-sea-salts, and dust. The highest mean mixing ratios of water-soluble ions and soot were observed at the lowest altitudes (a km) in the Channel sector. The bulk of the aerosol mass exported from Asia emanates h m Channel at both low and midaltitudes, due to the prevalence of dust compared to other sectors. Number densities show enhanced fine particles for Channel and NNW, while their volume distributions are enhanced due to sea salt and dust Low-altitude Channel exhibits the highest condensation nuclei ((34) number densities along with enhanced scattering coefficients, compared to the other sectors. At midaltitudes (2-7 km), low mean CN number densities coupled with a high proportion of nonvolatile particles (265%) observed in polluted sectors (Channel and NNW) are attributed to wet scavenging which removes hygroscopic CN particles. Low single scatter albedo m SE Asia reflects enhanced soot

  1. Chemical and physical properties of bulk aerosols within four sectors observed during TRACE-P

    NASA Astrophysics Data System (ADS)

    Jordan, C. E.; Anderson, B. E.; Talbot, R. W.; Dibb, J. E.; Fuelberg, H. E.; Hudgins, C. H.; Kiley, C. M.; Russo, R.; Scheuer, E.; Seid, G.; Thornhill, K. L.; Winstead, E.

    2003-11-01

    Chemical and physical aerosol data collected on the DC-8 during TRACE-P were grouped into four sectors based on back trajectories. The four sectors represent long-range transport from the west (WSW), regional circulation over the western Pacific and Southeast Asia (SE Asia), polluted transport from northern Asia with substantial sea salt at low altitudes (NNW) and a substantial amount of dust (Channel). WSW has generally low mixing ratios at both middle and high altitudes, with the bulk of the aerosol mass due to non-sea-salt water-soluble inorganic species. Low altitude SE Asia also has low mean mixing ratios in general, with the majority of the aerosol mass comprised of non-sea-salts, however, soot is also relatively important in this region. NNW had the highest mean sea salt mixing ratios, with the aerosol mass at low altitudes (<2 km) evenly divided between sea salts, non-sea-salts, and dust. The highest mean mixing ratios of water-soluble ions and soot were observed at the lowest altitudes (<2 km) in the Channel sector. The bulk of the aerosol mass exported from Asia emanates from Channel at both low and midaltitudes, due to the prevalence of dust compared to other sectors. Number densities show enhanced fine particles for Channel and NNW, while their volume distributions are enhanced due to sea salt and dust. Low-altitude Channel exhibits the highest condensation nuclei (CN) number densities along with enhanced scattering coefficients, compared to the other sectors. At midaltitudes (2-7 km), low mean CN number densities coupled with a high proportion of nonvolatile particles (≥65%) observed in polluted sectors (Channel and NNW) are attributed to wet scavenging which removes hygroscopic CN particles. Low single scatter albedo in SE Asia reflects enhanced soot.

  2. Comprehensive School Physical Activity Programs: Characteristics of Trained Teachers

    ERIC Educational Resources Information Center

    Centeio, Erin E.; Erwin, Heather; Castelli, Darla M.

    2014-01-01

    As public health concerns about physical inactivity and childhood obesity continue to rise, researchers are calling for interventions that comprehensively lead to more opportunities to participate in physical activity (PA). The purpose of this study was to examine the characteristics and attitudes of trained physical education teachers during the…

  3. Chemical and physical properties of single aerosol particles using a quadrupole trap

    SciTech Connect

    Carleton, K.L.; Sonnenfroh, D.M.; Kang, S.

    1995-12-31

    The importance of aerosols in controlling the chemical balance of the stratosphere has been demonstrated through studies of the polar ozone hole and polar stratospheric clouds. Our laboratory program is designed to explore the physical and chemical properties of aerosol particles under stratospheric conditions for single particles suspended in the electrodynamic field of a quadrupole trap. The goal of this work is to provide data on important stratospheric processes, with particular attention to processes resulting from increased aircraft emissions from the current subsonic fleet or a proposed fleet of supersonic aircraft. Optical methods including Mie scattering and Raman spectroscopy are used to probe the phase and composition of individual particles. Results will be presented on the freezing behavior of sulfuric acid particles.

  4. Megacity emission plume characteristics in summer and winter investigated by mobile aerosol and trace gas measurements: the Paris metropolitan area

    NASA Astrophysics Data System (ADS)

    von der Weiden-Reinmüller, S.-L.; Drewnick, F.; Zhang, Q. J.; Freutel, F.; Beekmann, M.; Borrmann, S.

    2014-05-01

    For the investigation of megacity emission plume characteristics mobile aerosol and trace gas measurements were carried out in the greater Paris region in July 2009 and January/February 2010 within the EU FP7 MEGAPOLI project. The deployed instruments measured physical and chemical properties of sub-micron aerosol particles, gas phase constituents of relevance for urban air pollution studies and meteorological parameters. The emission plume was identified based on fresh pollutant (e.g. particle-bound polycyclic aromatic hydrocarbons, black carbon, CO2 and NOx) concentration changes in combination with wind direction data. The classification into megacity influenced and background air masses allowed a characterization of the emission plume during summer and winter environmental conditions. On average, a clear increase of fresh pollutant concentrations in plume compared to background air masses was found for both seasons. For example, an average increase of 190% (+8.8 ng m-3) in summer and of 130% (+18.1 ng m-3) in winter was found for particle-bound polycyclic aromatic hydrocarbons in plume air masses. The aerosol particle size distribution in plume air masses was influenced by nucleation and growth due to coagulation and condensation in summer, while in winter only the second process seemed to be initiated by urban pollution. The observed distribution of fresh pollutants in the emission plume - its cross sectional Gaussian-like profile and the exponential decrease of pollutant concentrations with increasing distance to the megacity - are in agreement with model results. Differences between model and measurements were found for plume center location, plume width and axial plume extent. In general, dilution was identified as the dominant process determining the axial variations within the Paris emission plume. For in-depth analysis of transformation processes occurring in the advected plume, simultaneous measurements at a suburban measurement site and a stationary

  5. Megacity emission plume characteristics in summer and winter investigated by mobile aerosol and trace gas measurements: the Paris metropolitan area

    NASA Astrophysics Data System (ADS)

    von der Weiden-Reinmüller, S.-L.; Drewnick, F.; Zhang, Q. J.; Freutel, F.; Beekmann, M.; Borrmann, S.

    2014-12-01

    For the investigation of megacity emission plume characteristics mobile aerosol and trace gas measurements were carried out in the greater Paris region in July 2009 and January-February 2010 within the EU FP7 MEGAPOLI project (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation). The deployed instruments measured physical and chemical properties of sub-micron aerosol particles, gas phase constituents of relevance for urban air pollution studies and meteorological parameters. The emission plume was identified based on fresh pollutant (e.g., particle-bound polycyclic aromatic hydrocarbons, black carbon, CO2 and NOx) concentration changes in combination with wind direction data. The classification into megacity influenced and background air masses allowed a characterization of the emission plume during summer and winter environmental conditions. On average, a clear increase of fresh pollutant concentrations in plume compared to background air masses was found for both seasons. For example, an average increase of 190% (+ 8.8 ng m-3) in summer and of 130% (+ 18.1 ng m-3) in winter was found for particle-bound polycyclic aromatic hydrocarbons in plume air masses. The aerosol particle size distribution in plume air masses was influenced by nucleation and growth due to coagulation and condensation in summer, while in winter only the latter process (i.e., particle growth) seemed to be initiated by urban pollution. The observed distribution of fresh pollutants in the emission plume - its cross sectional Gaussian-like profile and the exponential decrease of pollutant concentrations with increasing distance to the megacity - are in agreement with model results. Differences between model and measurements were found for plume center location, plume width and axial plume extent. In general, dilution was identified as the dominant process determining the axial variations within the Paris

  6. Self-Consciousness, Evaluation of Physical Characteristics, and Physical Attractiveness.

    ERIC Educational Resources Information Center

    Turner, Robert G.; Gilliland, LuNell

    1981-01-01

    Investigated the relationship between public self-consciousness and speed of processing information about self. Results indicated that high public self-conciousness subjects required less time to report evaluations of their physical features. In a second study high public self-conciousness was shown to be positively related to judged physical…

  7. Chemical composition and characteristics of ambient aerosols and rainwater residues during Indian summer monsoon: Insight from aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida N.

    2016-07-01

    Real time composition of non-refractory submicron aerosol (NR-PM1) is measured via Aerosol mass spectrometer (AMS) for the first time during Indian summer monsoon at Kanpur, a polluted urban location located at the heart of Indo Gangetic Plain (IGP). Submicron aerosols are found to be dominated by organics followed by nitrate. Source apportionment of organic aerosols (OA) via positive matrix factorization (PMF) revealed several types of secondary/oxidized and primary organic aerosols. On average, OA are completely dominated by oxidized OA with a very little contribution from biomass burning OA. During rain events, PM1 concentration is decreased almost by 60%, but its composition remains nearly the same. Oxidized OA showed slightly more decrease than primary OAs, probably due to their higher hygroscopicity. The presence of organo nitrates (ON) is also detected in ambient aerosols. Apart from real-time sampling, collected fog and rainwater samples were also analyzed via AMS in offline mode and in the ICP-OES (Inductively coupled plasma - Optical emission spectrometry) for elements. The presence of sea salt, organo nitrates and sulfates has been observed. Rainwater residues are also dominated by organics but their O/C ratios are 15-20% lower than the observed values for ambient OA. Alkali metals such as Ca, Na, K are found to be most abundant in the rainwater followed by Zn. Rainwater residues are also found to be much less oxidized than the aerosols present inside the fog water, indicating presence of less oxidized organics. These findings indicate that rain can act as an effective scavenger of different types of pollutants even for submicron particle range. Rainwater residues also contain organo sulfates which indicate that some portion of the dissolved aerosols has undergone aqueous processing, possibly inside the cloud. Highly oxidized and possibly hygroscopic OA during monsoon period compared to other seasons (winter, post monsoon), indicates that they can act

  8. Effects of crop residue burning on aerosol properties, plume characteristics, and long-range transport over northern India

    NASA Astrophysics Data System (ADS)

    Kaskaoutis, D. G.; Kumar, S.; Sharma, D.; Singh, R. P.; Kharol, S. K.; Sharma, M.; Singh, A. K.; Singh, S.; Singh, Atinderpal; Singh, D.

    2014-05-01

    Aerosol emissions from biomass burning are of specific interest over the globe due to their strong radiative impacts and climate implications. The present study examines the impact of paddy crop residue burning over northern India during the postmonsoon (October-November) season of 2012 on modification of aerosol properties, as well as the long-range transport of smoke plumes, altitude characteristics, and affected areas via the synergy of ground-based measurements and satellite observations. During this period, Moderate Resolution Imaging Spectroradiometer (MODIS) images show a thick smoke/hazy aerosol layer below 2-2.5 km in the atmosphere covering nearly the whole Indo-Gangetic Plains (IGP). The air mass trajectories originating from the biomass-burning source region over Punjab at 500 m reveal a potential aerosol transport pathway along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient. Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres (AOD500 nm > 1.0) over six IGP locations, high values of Ångström exponent (>1.2), high particulate mass 2.5 (PM2.5) concentrations (>100-150 µgm-3), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (~2.5) and NO2 concentrations (~6 × 1015 mol/cm2), indicating the dominance of smoke aerosols from agricultural crop residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol properties, modification, and mixing atmospheric

  9. Composition and physical properties of the Asian Tropopause Aerosol Layer and the North American Tropospheric Aerosol Layer

    NASA Astrophysics Data System (ADS)

    Yu, Pengfei; Toon, Owen B.; Neely, Ryan R.; Martinsson, Bengt G.; Brenninkmeijer, Carl A. M.

    2015-04-01

    Recent studies revealed layers of enhanced aerosol scattering in the upper troposphere and lower stratosphere over Asia (Asian Tropopause Aerosol Layer (ATAL)) and North America (North American Tropospheric Aerosol Layer (NATAL)). We use a sectional aerosol model (Community Aerosol and Radiation Model for Atmospheres (CARMA)) coupled with the Community Earth System Model version 1 (CESM1) to explore the composition and optical properties of these aerosol layers. The observed aerosol extinction enhancement is reproduced by CESM1/CARMA. Both model and observations indicate a strong gradient of the sulfur-to-carbon ratio from Europe to the Asia on constant pressure surfaces. We found that the ATAL is mostly composed of sulfates, surface-emitted organics, and secondary organics; the NATAL is mostly composed of sulfates and secondary organics. The model also suggests that emission increases in Asia between 2000 and 2010 led to an increase of aerosol optical depth of the ATAL by 0.002 on average which is consistent with observations.

  10. Uncertainties of simulated aerosol optical properties induced by assumptions on aerosol physical and chemical properties: an AQMEII-2 perspective

    EPA Science Inventory

    The calculation of aerosol optical properties from aerosol mass is a process subject to uncertainty related to necessary assumptions on the treatment of the chemical species mixing state, density, refractive index, and hygroscopic growth. In the framework of the AQMEII-2 model in...

  11. Analysis of the chemical and physical properties of combustion aerosols: Properties overview

    EPA Science Inventory

    Aerosol chemical composition is remarkably complex. Combustion aerosols can comprise tens of thousands of organic compounds and fragments, refractory carbon, metals, cations, anions, salts, and other inorganic phases and substituents [Hays et al., 2004]. Aerosol organic matter no...

  12. Physical properties of antibiotic aerosols produced by jet and ultrasonic nebulizers.

    PubMed

    Takanami, C; Goto, Y

    1990-01-01

    The drug stability and the physical properties of aerosol of five different antibiotics were compared for ultrasonic and jet-type nebulization. These antibiotics were used alone, as well as combined with betamethasone sodium phosphate and/or tyloxapol glycerol sodium bicarbonate. The parameters investigated were changes in appearance, pH, temperature, viscosity, specific gravity and the residual potency of the antibiotics. No significant change was shown in appearance, viscosity and specific gravity. Temperatures of the solutions in the ultrasonic nebulizer cup increased with time, though almost no change after 10 minutes in the jet nebulizer. For pH, with antibiotics alone in the ultrasonic nebulizer, some drugs showed an increase, and other drugs showed a decrease, while generally a little change in the jet nebulizer. For residual potency, one drug showed decreased potency in the aerosol, though it was increased in the remnant solution, in contrast, another drug showed a tendency to increased potency in the aerosol and decreased potency in the remnant solution in the ultrasonic nebulizer. In the jet nebulizer, drugs showed generally slight increased potency and no difference among drugs. It was suggested that, with ultrasonic nebulization, in some drugs the solvents were nebulized and the principal ingredient tended to remain behind, while in other drugs the opposite occurred so that the effects were not uniform. PMID:10147674

  13. Effect of operation conditions of the drop-on-demand aerosol generator on aerosol characteristics: Pseudo-cinematographic and plasma mass spectrometric studies

    NASA Astrophysics Data System (ADS)

    Orlandini v. Niessen, Jan O.; Krone, Karin M.; Bings, Nicolas H.

    2014-02-01

    The recently presented drop-on-demand (DOD) aerosol generator overcomes some of the drawbacks of pneumatic nebulization, as its aerosol is no longer generated by gas-liquid interaction. In the current study, an advanced imaging technique is presented, based on a CCD camera equipped with magnifying telecentric optics to allow for fast, automated and precise aerosol characterization as well as fundamental studies on the droplet generation processes by means of pseudo-cinematography. The DOD aerosol generator is thoroughly characterized regarding its droplet size distribution, which shows few distinct populations rather than a continuous distribution. Other important figures, such as the Sauter diameter (D3,2) of 22 μm and the span of 0.4 were also determined. Additionally, the influence of the electrical operation conditions of the dosing device on the aerosol generation process is described. The number and volume of the generated droplets were found to be very reproducible and user-variable, e.g. from 17 to 27 μm (D3,2), within a span of 0.07-0.89. The performances of different setups of the DOD as liquid sample introduction system in ICP-MS are correlated to the respective achievable aerosol characteristics and are also compared to the performance of a state-of-the-art μ-flow nebulizer (EnyaMist). The DOD system allowed for improved sensitivity, but slightly elevated signal noise and overall comparable limits of detection. The results are critically discussed and future directions are outlined.

  14. Effect of ethanol on droplet size, efficiency of delivery, and clearance characteristics of technetium-99m DTPA aerosol.

    PubMed

    Sirr, S A; Juenemann, P J; Tom, H; Boudreau, R J; Chandler, R P; Loken, M K

    1985-06-01

    With recent technical advances in aerosol technology, the study of regional ventilation using [99mTc]DTPA aerosol has become increasingly popular. Using a cascade impactor, we have assessed droplet size distribution from a newly designed nebulizer. Delivery efficiency of [99mTc]DTPA aerosol to normal subjects was improved 70% with a 10% concentration of ethanol in the nebulizer. Using filter paper fixed to the delivery end of the aerosol device, and varying ethanol concentrations from 0-10%, an 87% increase of deposited radioactivity is measured. Use of higher concentration of ethanol to the nebulizer solution did not further improve delivery efficiency. The addition of ethanol did not alter clearance characteristics of [99mTc]DTPA from the lung nor did it affect droplet size distribution. PMID:3889235

  15. Effect of ethanol on droplet size, efficiency of delivery, and clearance characteristics of technetium-99m DTPA aerosol

    SciTech Connect

    Sirr, S.A.; Juenemann, P.J.; Tom, H.; Boudreau, R.J.; Chandler, R.P.; Loken, M.K.

    1985-06-01

    With recent technical advances in aerosol technology, the study of regional ventilation using (/sup 99m/Tc)DTPA aerosol has become increasingly popular. Using a cascade impactor, the authors have assessed droplet size distribution from a newly designed nebulizer. Delivery efficiency of (/sup 99m/Tc)DTPA aerosol to normal subjects was improved 70% with a 10% concentration of ethanol in the nebulizer. Using filter paper fixed to the delivery end of the aerosol device, and varying ethanol concentrations from 0-10%, an 87% increase of deposited radioactivity is measured. The addition of ethanol did not alter clearance characteristics of (/sup 99m/Tc)DTPA from the lung nor did it affect droplet size distribution.

  16. Characteristics of aerosol and meteorological parameters during major dust storm events (2005 - 2010) over Beijing, China

    NASA Astrophysics Data System (ADS)

    Zheng, Sheng; Cao, Chunxiang; Singh, Ramesh

    Multi satellite sensors are capable in monitoring dust storm, its path and changes in atmospheric parameters. The present paper discusses aerosol optical properties and meteorological parameters during major dust storm events (2005-2010) over Beijing, China. The back trajectory model shows that the dust is transported from the Inner Mongolia and Mongolia to Beijing. High aerosol optical depth (AOD) and low Ångström exponent (AE) values are observed during dusty days, the average AOD (675 nm) and AE (440-870 nm) during dusty days are 2.33 and 0.06, respectively. The aerosol size distribution (ASD) in coarse mode shows a large increase in the volume during dusty days. The single scattering albedo (SSA) increases with higher wavelength on dusty days, and higher compared to non-dusty days, indicating the presence of high scattering particles due to dust storm events. Characteristics of particles during dusty and non-dusty days are also supported by the real and imaginary parts of refractive index (RI). High air pollution index (API) during dusty days represent poor air quality is a serious health hazard at the time of dust events. The CO volume mixing ratio (COVMR) from Atmospheric Infrared Sounder (AIRS) shows decrease on the ground on dusty days, while the relative humidity (RH) and H _{2}0 mass mixing ratio (H _{2}OMMR) enhance. In addition, due to the dust storm in 2005, enhanced level of water vapor (WV) using Moderate Resolution Imaging Spectroradiometer (MODIS) data is observed in and around Beijing over the dust storms track.

  17. Characteristics of atmospheric aerosol optical depth variation in China during 1993-2012

    NASA Astrophysics Data System (ADS)

    Xu, Xiaofeng; Qiu, Jinhuan; Xia, Xiangao; Sun, Ling; Min, Min

    2015-10-01

    The long-term variations of atmospheric aerosol optical depth (AOD) over 14 first-class solar radiation stations in China during 1993-2012 are studied. The AOD at 750 nm wavelength is retrieved with the hourly accumulated direct solar radiation by using a broadband extinction method. The retrievals are validated in comparison with AERONET (Aerosol Robotic Network) and MODIS (Moderate Resolution Imaging Spectroradiometer) AOD products. For the comparison with AERONET, the correlation coefficient (R), mean bias error (MBE) and root mean square error (RMSE) of the monthly mean AODs are respectively 0.848, 0.029 and 0.101. Based on the statistical analysis, the monthly, seasonal and annual AOD variation characteristics are categorized as follow: (1) There are three major types of the seasonal AOD variations, which shows the largest seasonal averaged AOD appearing in spring, summer and winter. The smallest seasonal averaged AOD appears mostly in autumn. (2) Beijing and Guangzhou show a significant decreasing trend of the yearly AOD, while an increasing tendency appears in Zhengzhou, Shanghai, Kunming, Kashi and Wuhan. Although no significant variation trends are found, some fluctuations appear in the 20-year period in other cities. (3) The 20-year mean AOD ranges from 0.135 (Lhasa) to 0.678 (Zhengzhou). The aerosol hygroscopic growth contributes a lot to AOD in major cities in the eastern part of China, while not in most cities in the western part. A simple correction method is applied for enhancing the relationship of AOD and PM2.5 concentration.

  18. Carbonaceous aerosol and its characteristics observed in Tokyo and south Kanto region

    NASA Astrophysics Data System (ADS)

    Minoura, Hiroaki; Morikawa, Tazuko; Mizohata, Akira; Sakamoto, Kazuhiko

    2012-12-01

    Due to enforcing vehicle emission reduction requirements in Japan, particulate matter (PM) concentration, especially elemental carbon (EC) concentration in roadside atmosphere, obviously decreased in the last decade. In spite of the previous vehicle emission reduction, EC concentration was not shown a clear decrease, recently. To achieve the PM2.5 environmental standard, measurements based on emission source contribution are desirable. However, source apportionment of carbonaceous aerosol was ambiguous because chemical components are complicated, and the components change through photochemical reaction. The goal of this study is to determine source apportionment for carbonaceous aerosols. Examination of PM2.5 was performed in south Kanto including Tokyo in the summer of 2008 and the winter of 2009. Emissions from the industrial area around Tokyo Bay and the agricultural northern area showed transportation and accumulation due to the seasonal prevailing wind. The emissions formed a geographical distribution due to photochemical reactions. The characteristics of carbonaceous aerosol were obtained using carbon profile analysis and carbon isotope analysis, including the source information such as fossil fuel emission origin, vegetation origin, and combustion product, photochemical reaction product, etc. Soot-EC was found as a substance with fossil fuel origin which did not contain biomass combustion matter, and since it is stable, there was no observed difference by site and a uniform concentration was observed in winter. It became apparent from the carbon isotope analysis using 14C that the carbon from the biomass origin involved 29% in total carbon in the summer, and 48% in winter even at Kudan of central Tokyo.

  19. Characteristics of bacterial and fungal aerosols during the autumn haze days in Xi'an, China

    NASA Astrophysics Data System (ADS)

    Li, Yanpeng; Fu, Honglei; Wang, Wei; Liu, Jun; Meng, Qinglong; Wang, Wenke

    2015-12-01

    In recent years, haze pollution has become one of the most critical environmental issues in Xi'an, China, with particular matter (PM) being one of the top pollutants. As an important fraction of PM, bioaerosols may have adverse effects on air quality and human health. In this study, to better understand the characteristics of such biological aerosols, airborne microbial samples were collected by using an Andersen six-stage sampler in Xi'an from October 8th to 22nd, 2014. The concentration, size distribution and genera of airborne viable bacteria and fungi were comparably investigated during the haze days and non-haze days. Correlations of bioaerosol levels with meteorological parameters and PM concentrations were also examined. The results showed that the daily average concentrations of airborne viable bacteria and fungi during the haze days, 1102.4-1736.5 and 1466.2-1703.9 CFU/m3, respectively, were not only much higher than those during the non-haze days, but also exceeded the recommended permissible limit values. Comparing to size distributions during the non-haze days, slightly different patterns for bacterial aerosols and similar single-peak distribution pattern for fungal aerosols were observed during the haze days. Moreover, more allergic and infectious genera (e.g. Neisseria, Aspergillus, and Paecilomyces) in bioaerosols were identified during the haze days than during non-haze days. The present results reveal that bioaerosols may have more significant effects on public health and urban air quality during the haze days than during non-haze days.

  20. Characteristics of carbonaceous aerosol in the region of Beijing, Tianjin, and Hebei, China

    NASA Astrophysics Data System (ADS)

    Zhao, Pusheng; Dong, Fan; Yang, Yadong; He, Di; Zhao, Xiujuan; Zhang, Wenzong; Yao, Qing; Liu, Huaiyu

    2013-06-01

    More than 400 PM2.5 samples were collected at four urban sites in Beijing (BJ), Tianjin (TJ), Shijiazhuang (SJZ), and Chengde (CD), and also one site in Shangdianzi (SDZ), which was used as a regional background station, over four seasons from 2009 to 2010. The organic carbon (OC) and elemental carbon (EC) in each sample were analyzed. The average annual concentrations were 71.8-191.2 μg m-3 for PM2.5, 10.8-26.4 μg m-3 for OC, and 3.9-9.7 μg m-3 for EC at the five sites. OC and EC concentrations were lower in the spring and summer and much higher in the autumn and winter, mainly due to aerosol emissions from additional fuel combustion for heating. OC/EC ratios were lowest in the summer and highest in the winter at SDZ, BJ, TJ, and SJZ. These seasonal trends indicate that the characteristics of carbonaceous aerosol pollution were spatially similar and season-dependent in the plain area of Beijing, Tianjin, and Hebei (BTH). An EC tracer method was used to calculate the concentrations for secondary organic carbon (SOC); SOC concentrations were also higher in the autumn and winter and lowest during the summer at all five sites. A stable atmosphere and low temperatures, which were more frequent during the winter and autumn, facilitated the accumulation of air pollutants and accelerated the condensation or adsorption of volatile organic compounds in the BTH area. Over the past ten years (1999-2009), Beijing had observed a decrease in the EC concentrations during every season and a remarkable reduction in aerosol emissions from coal combustion for heating.

  1. The Nevada railroad system: Physical, operational, and accident characteristics

    SciTech Connect

    1991-09-01

    This report provides a description of the operational and physical characteristics of the Nevada railroad system. To understand the dynamics of the rail system, one must consider the system`s physical characteristics, routing, uses, interactions with other systems, and unique operational characteristics, if any. This report is presented in two parts. The first part is a narrative description of all mainlines and major branchlines of the Nevada railroad system. Each Nevada rail route is described, including the route`s physical characteristics, traffic type and volume, track conditions, and history. The second part of this study provides a more detailed analysis of Nevada railroad accident characteristics than was presented in the Preliminary Nevada Transportation Accident Characterization Study (DOE, 1990).

  2. IRRADIATION EFFECTS ON THE PHYSICAL CHARACTERISTICS OF SEWAGE SLUDGE

    SciTech Connect

    Lee, M-J.; Lee, J-K.; Yoo, D-H.; Ho, K.

    2004-10-05

    The radiation effects on the physical characteristic of the sewage sludge were studied in order to obtain information which will be used for study on the enhancement of the sludge's dewaterability. Water contents, capillary suction time, zeta potential, irradiation dose, sludge acidity, total solid concentration, sludge particle size and microbiology before and after irradiation were investigated. Irradiation gave an effect on physical characteristics sludge. Water content in sludge cake could be reduced by irradiation at the dose of 10kGy.

  3. Physical characteristics of welding arc ignition process

    NASA Astrophysics Data System (ADS)

    Shi, Linan; Song, Yonglun; Xiao, Tianjiao; Ran, Guowei

    2012-07-01

    The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack. The tungsten inert gas(TIG) touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis system. The changing phenomenon of main ionized element provided the electrons in the arc ignition is found. The metallic element is the main contributor to provide the electrons at the beginning of the discharging, and then the excitated shielding gas element replaces the function of the metallic element. The electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα. Through the discussion with the repeatability in relaxation phenomenon, the statistical regularity in the arc ignition process is analyzed. The similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas(MIG) arc ignition experiments. This research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.

  4. The optical, physical and chemical properties of the products of glyoxal uptake on ammonium sulfate seed aerosols

    NASA Astrophysics Data System (ADS)

    Trainic, M.; Riziq, A. A.; Lavi, A.; Flores, J. M.; Rudich, Y.

    2011-07-01

    The heterogeneous reaction between gas phase glyoxal and ammonium sulfate (AS) aerosols, a proxy for inorganic atmospheric aerosol, was studied in terms of the dependence of the optical, physical and chemical properties of the product aerosols on initial particle size and ambient RH. The reactions were studied under different relative humidity (RH) conditions, varying from dry conditions (~20 % RH) and up to 90 % RH, covering conditions prevalent in many atmospheric environments. At λ = 355 nm, the reacted aerosols demonstrate a substantial growth in optical extinction cross section, as well as in mobility diameter under a broad range of RH values (35-90 %). The ratio of the product aerosol to seed aerosol geometric cross section reached up to ~3.5, and the optical extinction cross-section up to ~250. The reactions show a trend of increasing physical and optical growth with decreasing seed aerosol size, from 100nm to 300 nm, as well as with decreasing RH values from 90 % to ~40 %. Optically inactive aerosols, at the limit of the Mie range (100 nm diameter) become optically active as they grow due to the reaction. AMS analyses of the reaction of 300 nm AS at RH values of 50 %, 75 % and 90 % show that the main products of the reaction are glyoxal oligomers, formed by acetal formation in the presence of AS. In addition, imidazole formation, which is a minor channel, is observed for all reactions, yielding a product which absorbs at λ = 290 nm, with possible implications on the radiative properties of the product aerosols. The ratio of absorbing substances (C-N compounds, including imidazoles) increases with increasing RH value. A core/shell model used for the investigation of the optical properties of the reaction products of AS 300nm with gas phase glyoxal, shows that the refractive index (RI) of the reaction products are in the range between 1.57-1.71 for the real part and between 0-0.02 for the imaginary part of the RI at 355 nm. The observed increase in the

  5. Salience of physical appearance characteristics among young women in Thailand.

    PubMed

    Rongmuang, Daravan; Corte, Colleen; McCreary, Linda L; Park, Chang G; Miller, Arlene; Gallo, Agatha

    2011-09-01

    Our aim in the present study was to identify key components of physical appearance among young Thai women. Free listings, focus groups and pile sorting were used. One-hundred twenty young women generated 78 unique physical appearance characteristics. Ninety-four nursing students validated these characteristics in focus groups and then sorted them into piles that reflected separate domains of physical appearance and labeled them. Salience analysis revealed that facial appearance (e.g., bright facial skin, high nose bridge, big eyes) was the most important domain, followed by body weight and shape, skin color and texture, hair (color, texture, length), and 'other' physical appearance (e.g., slender neck, slim fingers). This is the first study to identify aspects of physical appearance that are most salient to young Thai women and that may differ from women in other cultural contexts. These findings could be used to develop culturally grounded measures of physical appearance in Thai women. PMID:21768001

  6. HCl in rocket exhaust clouds - Atmospheric dispersion, acid aerosol characteristics, and acid rain deposition

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Sebacher, D. I.; Bendura, R. J.; Wornom, D. E.

    1983-01-01

    Both measurements and model calculations of the temporal dispersion of peak HCl (g + aq) concentration in Titan III exhaust clouds are found to be well characterized by one-term power-law decay expressions. The respective coefficients and decay exponents, however, are found to vary widely with meteorology. The HCl (g), HCl (g + aq), dewpoint, and temperature-pressure-altitude data for Titan III exhaust clouds are consistent with accurately calculated HCl/H2O vapor-liquid compositions for a model quasi-equilibrated flat surface aqueous aerosol. Some cloud evolution characteristics are also defined. Rapid and extensive condensation of aqueous acid clearly occurs during the first three min of cloud rise. Condensation is found to be intensified by the initial entrainment of relatively moist ambient air from lower levels, that is, from levels below eventual cloud stabilization. It is pointed out that if subsequent dilution air at stabilization altitude is significantly drier, a state of maximum condensation soon occurs, followed by an aerosol evaporation phase.

  7. Characteristics of major secondary ions in typical polluted atmospheric aerosols during autumn in central Taiwan.

    PubMed

    Fang, Guor-Cheng; Lin, Shih-Chieh; Chang, Shih-Yu; Lin, Chuan-Yao; Chou, Charles-C K; Wu, Yun-Jui; Chen, Yu-Chieh; Chen, Wei-Tzu; Wu, Tsai-Lin

    2011-06-01

    In autumn of 2008, the chemical characteristics of major secondary ionic aerosols at a suburban site in central Taiwan were measured during an annually occurring season of high pollution. The semicontinuous measurement system measured major soluble inorganic species, including NH(4)(+), NO(3)(-), and SO(4)(2-), in PM(10) with a 15 min resolution time. The atmospheric conditions, except for the influences of typhoons, were dominated by the local sea-land breeze with clear diurnal variations of meteorological parameters and air pollutant concentrations. To evaluate secondary aerosol formation at different ozone levels, daily ozone maximum concentration (O(3,daily max)) was used as an index of photochemical activity for dividing between the heavily polluted period (O(3,daily max) ≧80 ppb) and the lightly polluted period (O(3,daily max)<80 ppb). The concentrations of PM(10), NO(3)(-), SO(4)(2-), NH(4)(+) and total major ions during the heavily polluted period were 1.6, 1.9, 2.4, 2.7 and 2.3 times the concentrations during the lightly polluted period, respectively. Results showed that the daily maximum concentrations of PM(10) occurred around midnight and the daily maximum ozone concentration occurred during daytime. The average concentration of SO(2) was higher during daytime, which could be explained by the transportation of coastal industry emissions to the sampling site. In contrast, the high concentration of NO(2) at night was due to the land breeze flow that transport inland urban air masses toward this site. The simulations of breeze circulations and transitions were reflected in transports and distributions of these pollutants. During heavily polluted periods, NO(3)(-) and NH(4)(+) showed a clear diurnal variations with lower concentrations after midday, possibly due to the thermal volatilization of NH(4)NO(3) during daytime and transport of inland urban plume at night. The diurnal variation of PM(10) showed the similar pattern to that of NO(3)(-) and NH(4

  8. Variability in Aerosol Optical and Physical Properties at a Coastal Industrial City in India, deduced from OMI and MODIS data

    NASA Astrophysics Data System (ADS)

    Das, B.; Ahn, C.; Torres, O.

    2009-12-01

    Many cities in India have gone through industrial revolution due to the priorities put by the State and Central Governments for economical growth. Bhubaneswar is one of the cities in the eastern part of India (85.8 E and 20.2 N) that has been the center of industrial activities since 1990s. A number of industries such as thermal power plants, sponge iron plants and housing developments have resulted changes in the land cover and in the slow deterioration of air quality affecting public health and reduced visibility. The primary purpose of this study is to understand the variability in aerosol optical and physical properties in Bhubaneswar using remote sensing data produced by OMI (Ozone Monitoring Instrument) and MODIS (Moderate Resolution Imaging Spectroradiometer). We have analyzed the data for Aerosol Extiction Optical Depth (AOD), Aerosol Absorption Optical Depth (AAOD), UV Aerosol Index and Cloud Fraction from OMI and Aerosol Small Mode Fraction, Aerosol Optical Depth (AOD), Cloud Optical Depth (COD), Aerosol Mass over Land from MODIS. The analysis has been made for 4 years from 2005-2008. Variations in AOD and AAOD values are observed during pre-monsoon, monsoon and post-monsoon periods.

  9. Characteristics and origins of carbonaceous aerosol in the Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Chen, Yuan; Xie, Shaodong; Luo, Bin; Zhai, Chongzhi

    2014-09-01

    The Sichuan Basin is a low visibility area in southwest China, where the hilly and basin topography, plus humid and stagnant weather, lead to unique pollution patterns. To identify the characteristics and sources of carbonaceous aerosols, one-year record of 24-h PM2.5 samples were analyzed for organic carbon (OC) and elemental carbon (EC) content following the thermal/optical transmission protocol at three cities (Chengdu (CD), Neijiang (NJ), and Chongqing (CQ)) in the region during May 2012 to April 2013. The annual average concentrations were 19.0 ± 13.3 μg OC m-3 and 4.6 ± 2.6 μg EC m-3 in CD, 18.3 ± 8.4 μg OC m-3 and 4.1 ± 1.8 μg EC m-3 in NJ, and 15.2 ± 8.4 μg OC m-3 and 4.0 ± 1.6 μg EC m-3 in CQ, respectively. Organic matter (1.6OC) plus EC contributed about 40% of PM2.5 mass and displayed weak regional uniformity. Relatively high ratios of OC to EC were observed in the region with 4.3 for CD, 4.6 for NJ, and 3.8 for CQ, respectively. OC and EC pollution in the region exhibited interesting season-dependent characteristics with the lowest concentrations and OC/EC ratios in summer, but higher levels in other seasons. Higher OC/EC ratios in spring and autumn resulted from biomass burning, and in winter were from the enhanced secondary organic aerosol formation under favorable conditions. The exceptionally high OC and EC levels in May and October, mostly notable in CD, resulted from the burning of agricultural residues during harvest period. The high K+ concentrations and the high Kexcess/EC ratios implied the persistent influence of biomass burning throughout the year. Using a novel technique combing the EC tracer method and potassium mass balance in the aerosols, a K/EC ratio of 1.22 was used to retrieve the OC from biomass burning and the estimated contributions were 30.8%, 28.3%, and 21.9% in CD, NJ, and CQ, respectively, while secondary OC contributions to OC were 26.7%, 24.6%, and 25.7% in CD, NJ, and CQ, respectively.

  10. Measurements of the chemical, physical, and optical properties of single aerosol particles

    NASA Astrophysics Data System (ADS)

    Moffet, Ryan Christopher

    Knowledge of aerosol physical, chemical, optical properties is essential for judging the effect that particulates have on human health, climate and visibility. The aerosol time-of-flight mass spectrometer (ATOFMS) is capable of measuring, in real-time, the size and chemical composition of atmospheric aerosols. This was exemplified by the recent deployments of the ATOFMS to Mexico City and Riverside. The ATOFMS provided rapid information about the major particle types present in the atmosphere. Industrial sources of particles, such as fine mode particles containing lead, zinc and chloride were detected in Mexico City. The rapid time response of the ATOFMS was also exploited to characterize a coarse particle concentrator used in human health effects studies. The ATOFMS showed the ability to detect changes in particle composition with a time resolution of 15 min during short 2 hour human exposure studies. As a major component of this work, an optical measurement has been added to the ATOFMS. The scattered light intensity was acquired for each sized and chemically analyzed particle. This scattering information together with the particle aerodynamic diameter, enabled the refractive index and density of the aerosol to be retrieved. This method was validated in the laboratory using different test particles such as oils, aqueous salt solutions and black carbon particles. It was found that the nozzle-type inlet does not evaporate aqueous salt particles as has been observed for aerodynamic lens inlets. These new optical and microphysical measurements were integrated into the ATOFMS for field deployment in Riverside and Mexico City. For both cities, the different mixing states were found to have unique refractive indexes and densities. A fraction of the strongly absorbing elemental carbon particles were observed to have a spherical morphology due to heavy mixing with secondary species. In addition to the quantitative refractive index and effective density measurements

  11. Optical, physical and chemical properties of transported African mineral dust aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Di Biagio, Claudia; Chevaillier, Servanne; Gaimoz, Cécile; Grand, Noel; Loisil, Rodrigue; Triquet, Sylvain; Zapf, Pascal; Roberts, Greg; Bourrianne, Thierry; Torres, Benjamin; Blarel, Luc; Sellegri, Karine; Freney, Evelyn; Schwarzenbock, Alfons; Ravetta, François; Laurent, Benoit; Mallet, Marc; Formenti, Paola

    2014-05-01

    The transport of mineral dust aerosols is a global phenomenon with strong climate implications. Depending on the travel distance over source regions, the atmospheric conditions and the residence time in the atmosphere, various transformation processes (size-selective sedimentation, mixing, condensation of gaseous species, and weathering) can modify the physical and chemical properties of mineral dust, which, in turn, can change the dust's optical properties. The model predictions of the radiative effect by mineral dust still suffer of the lack of certainty of these properties, and their temporal evolution with transport time. Within the frame of the ChArMex project (Chemistry-Aerosol Mediterranean experiment, http://charmex.lsce.ipsl.fr/), two intensive airborne campaigns (TRAQA, TRansport and Air QuAlity, 18 June - 11 July 2012, and ADRIMED, Aerosol Direct Radiative Impact in the regional climate in the MEDiterranean region, 06 June - 08 July 2013) have been performed over the Central and Western Mediterranean, one of the two major transport pathways of African mineral dust. In this study we have set up a systematic strategy to determine the optical, physical and optical properties of mineral dust to be compared to an equivalent dataset for dust close to source regions in Africa. This study is based on airborne observations onboard the SAFIRE ATR-42 aircraft, equipped with state of the art in situ instrumentation to measure the particle scattering and backscattering coefficients (nephelometer at 450, 550, and 700 nm), the absorption coefficient (PSAP at 467, 530, and 660 nm), the extinction coefficient (CAPS at 530 nm), the aerosol optical depth (PLASMA at 340 to 1640 nm), the size distribution in the extended range 40 nm - 30 µm by the combination of different particle counters (SMPS, USHAS, FSSP, GRIMM) and the chemical composition obtained by filter sampling. The chemistry and transport model CHIMERE-Dust have been used to classify the air masses according to

  12. Summary of long-term data on latitudinal dependence of the near-water aerosol microphysical characteristics in eastern Atlantic

    NASA Astrophysics Data System (ADS)

    Pol'kin, Viktor V.; Sakerin, Sergey M.; Pol'kin, Vasily V.; Turchinovich, Ury S.; Terpugova, Swetlana A.; Tikhomirov, Aleksey B.; Radionov, Vladimir F.

    2015-11-01

    Latitudinal dependences of aerosol microphysical characteristics are analyzed. The data were obtained in the Russian Antarctic Expedition (RAE) onboard the expedition vessels "Akademik Fedorov" and "Akademik Treshnikov" in 2006- 2014, as well as the research vessel "Akademik Sergey Vavilov" in 2004.

  13. Microbiology and atmospheric processes: biological, physical and chemical characterization of aerosol particles

    NASA Astrophysics Data System (ADS)

    Georgakopoulos, D. G.; Després, V.; Fröhlich-Nowoisky, J.; Psenner, R.; Ariya, P. A.; Pósfai, M.; Ahern, H. E.; Moffett, B. F.; Hill, T. C. J.

    2008-04-01

    The interest in bioaerosols has traditionally been linked to health hazards for humans, animals and plants. However, several components of bioaerosols exhibit physical properties of great significance for cloud processes, such as ice nucleation and cloud condensation. To gain a better understanding of their influence on climate, it is therefore important to determine the composition, concentration, seasonal fluctuation, regional diversity and evolution of bioaerosols. In this paper, we will review briefly the existing techniques for detection, quantification, physical and chemical analysis of biological particles, attempting to bridge physical, chemical and biological methods for analysis of biological particles and integrate them with aerosol sampling techniques. We will also explore some emerging spectroscopy techniques for bulk and single-particle analysis that have potential for in-situ physical and chemical analysis. Lastly, we will outline open questions and further desired capabilities (e.g., in-situ, sensitive, both broad and selective, on-line, time-resolved, rapid, versatile, cost-effective techniques) required prior to comprehensive understanding of chemical and physical characterization of bioaerosols.

  14. Microbiology and atmospheric processes: biological, physical and chemical characterization of aerosol particles

    NASA Astrophysics Data System (ADS)

    Georgakopoulos, D. G.; Després, V.; Fröhlich-Nowoisky, J.; Psenner, R.; Ariya, P. A.; Pósfai, M.; Ahern, H. E.; Moffett, B. F.; Hill, T. C. J.

    2009-04-01

    The interest in bioaerosols has traditionally been linked to health hazards for humans, animals and plants. However, several components of bioaerosols exhibit physical properties of great significance for cloud processes, such as ice nucleation and cloud condensation. To gain a better understanding of their influence on climate, it is therefore important to determine the composition, concentration, seasonal fluctuation, regional diversity and evolution of bioaerosols. In this paper, we will review briefly the existing techniques for detection, quantification, physical and chemical analysis of biological particles, attempting to bridge physical, chemical and biological methods for analysis of biological particles and integrate them with aerosol sampling techniques. We will also explore some emerging spectroscopy techniques for bulk and single-particle analysis that have potential for in-situ physical and chemical analysis. Lastly, we will outline open questions and further desired capabilities (e.g., in-situ, sensitive, both broad and selective, on-line, time-resolved, rapid, versatile, cost-effective techniques) required prior to comprehensive understanding of chemical and physical characterization of bioaerosols.

  15. Characteristics of aerosol particles and trace gases in ship exhaust plumes

    NASA Astrophysics Data System (ADS)

    Drewnick, F.; Diesch, J.; Borrmann, S.

    2011-12-01

    Gaseous and particulate matter from marine vessels gain increasing attention due to their significant contribution to the anthropogenic burden of the atmosphere, implying the change of the atmospheric composition and the impact on local and regional air quality and climate (Eyring et al., 2010). As ship emissions significantly affect air quality of onshore regions, this study deals with various aspects of gas and particulate plumes from marine traffic measured near the Elbe river mouth in northern Germany. In addition to a detailed investigation of the chemical and physical particle properties from different types of commercial marine vessels, we will focus on the chemistry of ship plumes and their changes while undergoing atmospheric processing. Measurements of the ambient aerosol, various trace gases and meteorological parameters using a mobile laboratory (MoLa) were performed on the banks of the Lower Elbe which is passed on average, daily by 30 ocean-going vessels reaching the port of Hamburg, the second largest freight port of Europe. During 5 days of sampling from April 25-30, 2011 170 commercial marine vessels were probed at a distance of about 1.5-2 km with high temporal resolution. Mass concentrations in PM1, PM2.5 and PM10 and number as well as PAH and black carbon (BC) concentrations in PM1 were measured; size distribution instruments covered the size range from 6 nm up to 32 μm. The chemical composition of the non-refractory aerosol in the submicron range was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase species analyzers monitored various trace gas concentrations in the air and a weather station provided meteorological parameters. Additionally, a wide spectrum of ship information for each vessel including speed, size, vessel type, fuel type, gross tonnage and engine power was recorded via Automatic Identification System (AIS) broadcasts. Although commercial marine vessels powered by diesel engines consume high

  16. Dry Lung as a Physical Model in Studies of Aerosol Deposition.

    PubMed

    Morozov, Victor N; Kanev, Igor L

    2015-10-01

    A new physical model was developed to evaluate the deposition of micro- and nanoaerosol particles (NAPs) into the lungs as a function of size and charges. The model was manufactured of a dry, inflated swine lung produced by Nasco company (Fort Atkinson, WI). The dry lung was cut into two lobes and a conductive tube was glued into the bronchial tube. The upper 1-2-mm-thick layer of the lung lobe was removed with a razor blade to expose the alveoli. The lobe was further enclosed into a plastic bag and placed within a metalized plastic box. The probability of aerosol deposition was calculated by comparing the size distribution of NAPs passed through the lung with that of control, where aerosol passed through a box bypassing the lung. Using this new lung model, it was demonstrated that charged NAPs are deposited inside the lung substantially more efficiently than neutral ones. It was also demonstrated that deposition of neutral NAPs well fits prediction of the Multiple-Path Particle Dosimetry (MPPD) model developed by the Applied Research Associates, Inc. (ARA). PMID:26267596

  17. Differences in physical chemistry and dissolution rate of solid particle aerosols from solution pressurised inhalers.

    PubMed

    Buttini, Francesca; Miozzi, Michele; Balducci, Anna Giulia; Royall, Paul G; Brambilla, Gaetano; Colombo, Paolo; Bettini, Ruggero; Forbes, Ben

    2014-04-25

    Solution composition alters the dynamics of beclomethasone diproprionate (BDP) particle formation from droplets emitted by pressurised metered dose inhalers (pMDIs). The hypothesis that differences in inhaler solutions result in different solid particle physical chemistry was tested using a suite of complementary calorimetric techniques. The atomisation of BDP-ethanol solutions from commercial HFA-pMDI produced aerodynamically-equivalent solid particle aerosols. However, differences in particle physico-chemistry (morphology and solvate/clathrate formation) were detected by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and supported by hot stage microscopy (HSM). Increasing the ethanol content of the formulation from 8 to 12% (w/w), which retards the evaporation of propellant and slows the increase in droplet surface viscosity, enhanced the likelihood of particles drying with a smooth surface. The dissolution rate of BDP from the 12% (w/w) ethanol formulation-derived particles (63% dissolved over 120 min) was reduced compared to the 8% (w/w) ethanol formulation-derived particles (86% dissolved over 120 min). The addition of 0.01% (w/w) formoterol fumarate or 1.3% (w/w) glycerol to the inhaler solution modified the particles and reduced the BDP dissolution rate further to 34% and 16% dissolved in 120 min, respectively. These data provide evidence that therapeutic aerosols from apparently similar inhaler products, including those with similar aerodynamic performance, may behave non-equivalently after deposition in the lungs. PMID:24491530

  18. Characteristics of Missing Physical Activity Data in Children and Youth

    ERIC Educational Resources Information Center

    Zhuang, Jie; Chen, Peijie; Wang, Chao; Huang, Liang; Zhu, Zheng; Zhang, Wenjie; Fan, Xiang

    2013-01-01

    Purpose: The purpose of this study was to investigate the characteristics of missing physical activity (PA) data of children and youth. Method: PA data from the Chinese City Children and Youth Physical Activity Study ("N" = 2,758; 1,438 boys and 1,320 girls; aged 9-17 years old) were used for the study. After the data were sorted by the…

  19. New characteristics of submicron aerosols and factor analysis of combined organic and inorganic aerosol mass spectra during winter in Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, J. K.; Ji, D. S.; Liu, Z. R.; Hu, B.; Wang, L. L.; Huang, X. J.; Wang, Y. S.

    2015-07-01

    In recent years, an increasing amount of attention has been paid to heavy haze pollution in Beijing, China. In addition to Beijing's population of approximately 20 million and its 5 million vehicles, nearby cities and provinces are host to hundreds of heavily polluting industries. In this study, a comparison between observations in January 2013 and January 2014 showed that non-refractory PM1 (NR-PM1) pollution was weaker in January 2014, which was primarily caused by variations in meteorological conditions. For the first time, positive matrix factorization (PMF) was applied to the merged high-resolution mass spectra of organic and inorganic aerosols from aerosol mass spectrometer measurements in Beijing, and the sources and evolution of NR-PM1 in January 2014 were investigated. The two factors, NO3-OA1 and NO3-OA2, were primarily composed of ammonium nitrate, and each showed a different degree of oxidation and diurnal variation. The organic fraction of SO4-OA showed the highest degree of oxidation of all PMF factors. The hydrocarbon-like organic aerosol (OA) and cooking OA factors contained negligible amounts of inorganic species. The coal combustion OA factor contained a high contribution from chloride in its mass spectrum. The NR-PM1 composition showed significant variations in January 2014, in which the contribution of nitrate clearly increased during heavy pollution events. The most effective way to control fine particle pollution in Beijing is through joint prevention and control measures at the regional level, rather than a focus on an individual city, especially for severe haze events.

  20. Column-integrated aerosol optical and physical properties at a regional background atmosphere in North China Plain

    NASA Astrophysics Data System (ADS)

    Zhu, Jun; Che, Huizheng; Xia, Xiangao; Chen, Hongbin; Goloub, Phillipe; Zhang, Wenxing

    2014-02-01

    The AERONET level 2.0 data at Xinglong station from February 2006 to July 2011 were used to characterize the aerosol optical and physical properties, including temporal variability, aerosol absorption, classification and properties under dust and haze conditions. The annual mean aerosol optical depth (AOD) and extinction Angstrom exponent (EAE) are 0.28 ± 0.30 and 1.07 ± 0.38, respectively. The seasonal variations of AOD440nm are higher in spring (0.40 ± 0.3) and summer (0.40 ± 0.42) than in autumn (0.20 ± 0.22) and winter (0.19 ± 0.21). The EAE is low in spring (0.96 ± 0.43) and high in summer (1.22 ± 0.38). The EAE is ˜1.25 with an absorption Angstrom exponent (AAE) of ˜1.0-1.5 in Xinglong, which indicates that the dominant type is mixed aerosol (accounting for 88.2% at AAE > 1.0). Almost all of the dust observations occurred in spring. The volume concentrations of both fine and coarse mode particles increase with increasing AOD. In spring, the increase of coarse particles is greater than that of fine aerosols; however, the reverse phenomenon is observed for other seasons. The high AOD at Xinglong could be associated with the growth of fine mode aerosols and addition of coarse mode particles. This background station is not only impacted by dust aerosols from northwest China and south Mongolia but also influenced by long-range transportation of anthropogenic aerosols from south urban and industrialized regions. The mean AOD was 1.49 on the dust day, while AOD was 1.10 on the haze day. The mean EAEs were 0.09 and 1.43 on dust and haze days, respectively.

  1. Aerosol characteristics in a coastal region (results from MAPTIP) Professional paper

    SciTech Connect

    Gathman, S.G.; Jensen, D.R.

    1995-08-01

    In coastal areas, the simplifying assumptions of horizontal homogeneity used in open ocean analysis are not always useable. Various human-generated aerosol sources such as towns and industrial centers can provide a complex portrait of merging plumes of non-natural aerosols which are advected out to the littoral zones. The extensive meteorological and aerosol measurements made during the Marine Aerosol Properties and Thermal Imager Performance (MAPTIP) experiment provided an ideal opportunity to view how these aerosol were advected from their sources to the littoral zone of the North Sea. MAPTIP was conducted along the Dutch coast in October/November 1993. The NCCOSC, RDTE DIV (NRaD) instrumented Navajo aircraft flew two star pattern flights a day during the experiment at altitudes below 500 feet. During these flights, aerosol size distribution measurements along the flight path were being continuously recorded. These measurements were utilized for making aerosol concentration maps of the various sized aerosol groups. This paper shows the mesoscale effects of aerosol advection making the marine boundary layer in a littoral zone much more complicated than that of an open ocean.

  2. Aerosol size distribution characteristics of organosulfates in the Pearl River Delta region, China

    NASA Astrophysics Data System (ADS)

    Kuang, Bin Yu; Lin, Peng; Hu, Min; Yu, Jian Zhen

    2016-04-01

    Organosulfates (OSs) have been detected in various atmospheric environments, but their particle size distribution characteristics are unknown. In this work, we examined their size distributions in ambient aerosols to gain insights into the formation processes. Size-segregated aerosol samples in the range of 0.056-18 μm were collected using a ten-stage impactor at a receptor site in Hong Kong in both summer and winter and in Nansha in the Pearl River Delta in winter. The humic-like substances fraction in the size-segregated samples was isolated and analyzed using electrospray ionization coupled with an Orbitrap Ultra High Resolution Mass Spectrometer. Through accurate mass measurements, ∼190 CHOS and ∼90 CHONS formulas were tentatively identified to be OS compounds. Among them, OS compounds derived from isoprene, α-/β-pinene, and limonene and alkyl OSs having low double bond equivalents (DBE = 0,1) and 0-2 extra O beyond those in -OSO3 were found with high intensity. The biogenic volatile organic compounds-derived OS formulas share a common characteristic with sulfate in that the droplet mode dominated, peaking in either 0.56-1.0 or 1.0-1.8 μm size bin, reflecting sulfate as their common precursor. Most of these OSs have a minor coarse mode, accounting for 0-45%. The presence of OSs on the coarse particles is hypothesized to be a result of OSs on small particle (<0.32 μm) coagulating with coarse particles, as the abundance ratios of OS to non-sea-salt sulfate present on the coarse particles were similar to those on particles <0.32 μm. Among a few pairs of CHONS and CHOS that could be linked up through hydrolysis of a nitrooxy group in the CHONS form (e.g., m/z 294: C10H16O7NS- vs. m/z 249 C10H17O5S- from α/β-pinene, differing by (+H2O-HNO3)), the CHONS compounds had an enhanced coarse mode presence. This could be interpreted as a result of slower hydrolysis of the CHONS compounds on the alkali coarse particles. The low DBE alkyl OS compounds have a

  3. Oak Ridge Reservation. Physical Characteristics and National Resources

    SciTech Connect

    Parr, Patricia Dreyer; Joan, F. Hughes

    2006-10-09

    The topology, geology, hydrology, vegetation, and wildlife of the Oak Ridge Reservation (ORR) provide a complex and intricate array of resources that directly impact land stewardship and use decisions. The purpose of this document is to consolidate general information regarding the natural resources and physical characteristics of the ORR.

  4. Effect of adjuvant physical properties on spray characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of adjuvant physical properties on spray characteristics were studied. Dynamic surface tension was measured with a Sensa Dyne surface tensiometer 6000 using the maximum bubble pressure method. Viscosity was measured with a Brookfield synchro-lectric viscometer model LVT using a UL adap...

  5. 40 CFR 161.190 - Physical and chemical characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Physical and chemical characteristics. 161.190 Section 161.190 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Product Chemistry...

  6. 40 CFR 161.190 - Physical and chemical characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Physical and chemical characteristics. 161.190 Section 161.190 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Product Chemistry...

  7. 19 CFR 351.411 - Differences in physical characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Differences in physical characteristics. 351.411 Section 351.411 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Calculation of Export Price, Constructed Export Price, Fair Value, and Normal Value §...

  8. Characteristics of aerosol optical properties and meteorological parameters during three major dust events (2005-2010) over Beijing, China

    NASA Astrophysics Data System (ADS)

    Cao, Chunxiang; Zheng, Sheng; Singh, Ramesh P.

    2014-12-01

    Multi-satellite sensors are capable of monitoring transport and characteristics of dust storms and changes in atmospheric parameters along their transport. The present paper discusses aerosol optical properties and meteorological parameters during major dust storm events occurred in the period 2005-2010 over Beijing, China. The back trajectory model shows that the dust is transported from the Inner Mongolia and Mongolia arid regions to Beijing. High aerosol optical depth (AOD) at the wavelength 675 nm and low Ångström exponent (AE) values in the wavelength 440-870 nm are observed during dusty days. The aerosol size distribution (ASD) in coarse mode shows a large increase in the volume during dusty days. The single scattering albedo (SSA) increases with higher wavelength on dusty days, and is generally found to be higher compared to the days prior to and after the dust events, indicating the presence of high concentrations of scattering particles due to dust storm events. The physico-chemical properties of aerosols during dusty and non dusty days show distinct characteristics as reflected from the changes in the real and imaginary parts of refractive index (RI). In addition, the CO volume mixing ratio (COVMR) from Atmospheric Infrared Sounder (AIRS) shows a pronounced decrease on dusty days, while the H2O mass mixing ratio (H2OMMR) shows enhanced signal. Furthermore, enhanced level of water vapor (WV) using Moderate Resolution Imaging Spectroradiometer (MODIS) data is also observed in and around Beijing over the dust storms track.

  9. Measurement of physical characteristics of materials by ultrasonic methods

    DOEpatents

    Lu, W.Y.; Min, S.

    1998-09-08

    A method is described for determining and evaluating physical characteristics of a material. In particular, the present invention provides for determining and evaluating the anisotropic characteristics of materials, especially those resulting from such manufacturing processes as rolling, forming, extruding, drawing, forging, etc. In operation, a complex ultrasonic wave is created in the material of interest by any method. The wave form may be any combination of wave types and modes and is not limited to fundamental plate modes. The velocity of propagation of selected components which make up the complex ultrasonic wave are measured and evaluated to determine the physical characteristics of the material including, texture, strain/stress, grain size, crystal structure, etc. 14 figs.

  10. Measurement of physical characteristics of materials by ultrasonic methods

    DOEpatents

    Lu, Wei-yang; Min, Shermann

    1998-01-01

    A method is described for determining and evaluating physical characteristics of a material. In particular, the present invention provides for determining and evaluating the anisotropic characteristics of materials, especially those resulting from such manufacturing processes as rolling, forming, extruding, drawing, forging, etc. In operation, a complex ultrasonic wave is created in the material of interest by any method. The wave form may be any combination of wave types and modes and is not limited to fundamental plate modes. The velocity of propagation of selected components which make up the complex ultrasonic wave are measured and evaluated to determine the physical characteristics of the material including, texture, strain/stress, grain size, crystal structure, etc.

  11. Relationship between aerosol characteristics and altitude based on multi-measurements and model simulations

    NASA Astrophysics Data System (ADS)

    Nakata, Makiko; Ohshima, Tsubasa; Fujito, Toshiyuki; Sano, Itaru; Mukai, Sonoyo

    2010-10-01

    The suspending particulate matter (PM2.5) is a typical indicator of small particles in the atmosphere. Accordingly in order to monitor the air quality, sampling of PM2.5 has been widely undertaken over the world, especially in the urban cities. On the other hand, it is known that the sun photometry provides us with the aerosol information, e.g. aerosol optical thickness (AOT), aerosol size information and so on. Simultaneous measurements of PM2.5 and the AOT have been performed at a NASA/AERONET (Aerosol Robotics Network) site in urban city of Higashi-Osaka in Japan since March 2004, and successfully provided a linear correlation between PM2.5 and AOT in separately considering with several cases, e.g. usual, anthropogenic aerosols, dust aerosols and so on. This fact suggests that the vertical distribution also should be taken into account separately for each aerosol type. In this work, vertical profiles of atmospheric aerosols are considered based on combination use of photometric data with AERONET, LIDAR (Light Detection and Ranging) measurements and model simulations.

  12. Influence of continental outflow on aerosol chemical characteristics over the Arabian Sea during winter

    NASA Astrophysics Data System (ADS)

    Kumar, Ashwini; Sudheer, A. K.; Goswami, Vineet; Bhushan, Ravi

    2012-04-01

    The chemical composition of aerosol over the Arabian Sea was investigated during December 2007. Elemental Carbon (EC), Organic Carbon (OC), water soluble organic and inorganic constituents and crustal elements (Al, Fe, Ca, and Mg) were measured in total suspended particulate samples (TSP) collected from marine boundary layer of the Arabian Sea when the oceanic region is influenced by continental outflow. Anthropogenic and natural mineral aerosol originating from continental regions dominates the aerosol composition contributing ∼88% of total aerosol mass. The sea-salt aerosol comprises only ∼12% of TSP. The carbonaceous aerosol exhibits spatial trend similar to that of K+ suggesting major source could be biomass burning. Secondary organic aerosol (SOA) contribution estimated by EC-tracer method suggests that up to 67% of OC can be of secondary origin. Average water soluble organic carbon to OC ratio is ∼0.9, indicates significant formation of SOA during transport of continental air masses. These results demonstrate the dominance of continental aerosol over the Arabian Sea during wintertime where deposition may have major impact on surface ocean biogeochemistry.

  13. The regional distribution characteristics of aerosol optical depth over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Xu, C.; Ma, Y. M.; You, C.; Zhu, Z. K.

    2015-06-01

    The Tibetan Plateau (TP) is representative of typical clean atmospheric conditions. Aerosol optical depth (AOD) retrieved by Multi-angle Imaging SpectroRadiometer (MISR) is higher over Qaidam Basin than the rest of the TP all the year. Different monthly variation patterns of AOD are observed over the southern and northern TP, whereby the aerosol load is usually higher in the northern TP than in the southern part. The aerosol load over the northern part increases from April to June, peaking in May. The maximum concentration of aerosols over the southern TP occurs in July. Aerosols appear to be more easily transported over the main body of the TP across the northeastern edge rather than the southern edge. This is may be because the altitude is much lower at the northeastern edge than that of the Himalayas located along the southern edge of the TP. Three-dimensional distributions of dust, polluted dust, polluted continental and smoke are also investigated based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data. Dust is found to be the most prominent aerosol type on the TP, and other types of aerosols affect the atmospheric environment slightly. A natural boundary seems to extend to an altitude of 6-8 km a.s.l., which may act as a dividing line of higher dust occurrence in the northern TP and lower dust occurrence in the southern TP, especially in spring and summer. This boundary appears around 33-35° N in the middle of the plateau, and it is possibly associated with the high altitude terrain in the same geographic location. Comparisons of CALIPSO and MISR data show that this natural boundary extending to upper troposphere is consistent with the spatial pattern of aerosol loading. The whole TP blocks the atmospheric aerosols transported from surrounding regions, and the extreme high mountains on the TP also cause an obstruction to the transport of aerosols. The aerosol distribution patterns are primarily driven by atmospheric

  14. A one-dimensional model describing aerosol formation and evolution in the stratosphere. I - Physical processes and mathematical analogs. II - Sensitivity studies and comparison with observations

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Hamill, P.; Toon, O. B.; Whitten, R. C.; Kiang, C. S.

    1979-01-01

    A new time-dependent one-dimensional model of the stratospheric sulfate aerosol layer is developed. The model treats atmospheric photochemistry and aerosol physics in detail and includes the interaction between gases and particles explicitly. It is shown that the numerical algorithms used in the model are quite precise. Sensitivity studies and comparison with observations are made. The simulated aerosol physics generates a particle layer with most of the observed properties. The sensitivity of the calculated properties to changes in a large number of aeronomic aerosol parameters is discussed in some detail. The sensitivity analysis reveals areas where the aerosol model is most uncertain. New observations are suggested that might help resolve important questions about the origin of the stratospheric aerosol layer.

  15. Aerosols over Delhi during pre-monsoon months: Characteristics and effects on surface radiation forcing

    NASA Astrophysics Data System (ADS)

    Singh, Sachchidanand; Nath, Shambhu; Kohli, Ramesh; Singh, Risal

    2005-07-01

    The surface fluxes in the wavelength range 280-2800 nm were measured during the pre-monsoon period, April-June 2003 along with the spectral distribution of aerosol optical depth (AOD) in the visible and near infrared wavelengths. The Ångström exponent alpha retrieved from the data showed abundance of desert aerosols over Delhi during this period. The aerosol composition constructed using the OPAC model indicated a typical mixture of two aerosol types: urban and desert. Due to this the aerosol mixture had a very low value of single scattering albedo ~0.67. The average total radiative forcing efficiency observed at the surface in the broad wavelength band (280-2800 nm) was estimated and compared with the SBDART model calculated values.

  16. The optical, physical and chemical properties of the products of glyoxal uptake on ammonium sulfate seed aerosols

    NASA Astrophysics Data System (ADS)

    Trainic, M.; Abo Riziq, A.; Lavi, A.; Flores, J. M.; Rudich, Y.

    2011-09-01

    The heterogeneous reaction between gas phase glyoxal and ammonium sulfate (AS) aerosols, a proxy for inorganic atmospheric aerosol, was studied in terms of the dependence of the optical, physical and chemical properties of the product aerosols on initial particle size and ambient relative humidity (RH). Our experiments imitate an atmospheric scenario of a dry particle hydration at ambient RH conditions in the presence of glyoxal gas followed by efflorescence due to decrease of the ambient RH. The reactions were studied under different RH conditions, starting from dry conditions (~20% RH) and up to 90% RH, covering conditions prevalent in many atmospheric environments, and followed by consequent drying of the reacted particles before their analysis by the aerosol mass spectrometer (AMS), cavity ring down (CRD) and scanning mobility particle sizer (SMPS) systems. At λ = 355 nm, the reacted aerosols demonstrate a substantial growth in optical extinction cross section, as well as in mobility diameter under a broad range of RH values (35-90%). The ratio of the product aerosol to seed aerosol geometric cross section reached up to ~3.5, and the optical extinction cross-section up to ~250. The reactions show a trend of increasing physical and optical growth with decreasing seed aerosol size, from 100 nm to 300 nm, as well as with decreasing RH values from 90% to ~40%. Optically inactive aerosols, at the limit of the Mie range (100 nm diameter) become optically active as they grow due to the reaction. AMS analyses of the reaction of 300 nm AS at RH values of 50%, 75% and 90% show that the main products of the reaction are glyoxal oligomers, formed by acetal formation in the presence of AS. In addition, imidazole formation, which is a minor channel, is observed for all reactions, yielding a product which absorbs at λ = 290 nm, with possible implications on the radiative properties of the product aerosols. The ratio of absorbing substances (C-N compounds, including

  17. Characteristics and Mechanism of Cu Films Fabricated at Room Temperature by Aerosol Deposition.

    PubMed

    Lee, Dong-Won; Kwon, Oh-Yun; Cho, Won-Ju; Song, Jun-Kwang; Kim, Yong-Nam

    2016-12-01

    We were successful in growing a dense Cu film on Al2O3 substrates at room temperature using an aerosol deposition (AD) method. The characteristics of Cu films were investigated through electrical resistivity and X-ray photoelectron spectroscopy (XPS). The resistivity of Cu films was low (9.2-12.5 μΩ cm), but it was five to seven times higher than that of bulk copper. The deterioration of the resistivity indicates that a Cu2O phase with CuO occurs due to a particle-to-particle collision. Moreover, the growth of Cu films was investigated by observing their microstructures. At the initial stage in the AD process, the impacted particles were flattened and deformed on a rough Al2O3 substrate. The continuous collision of impacted particles leads to the densification of deposited coating layers due to the plastic deformation of particles. The bonding between the Cu particles and the rough Al2O3 substrate was explained in terms of the adhesive properties on the surface roughness of Al2O3 substrates. It was revealed that the roughness of substrates was considerably associated with the mechanical interlocking between Cu particles and rough Al2O3 substrate. PMID:27009529

  18. Characteristics and Mechanism of Cu Films Fabricated at Room Temperature by Aerosol Deposition

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Won; Kwon, Oh-Yun; Cho, Won-Ju; Song, Jun-Kwang; Kim, Yong-Nam

    2016-03-01

    We were successful in growing a dense Cu film on Al2O3 substrates at room temperature using an aerosol deposition (AD) method. The characteristics of Cu films were investigated through electrical resistivity and X-ray photoelectron spectroscopy (XPS). The resistivity of Cu films was low (9.2-12.5 μΩ cm), but it was five to seven times higher than that of bulk copper. The deterioration of the resistivity indicates that a Cu2O phase with CuO occurs due to a particle-to-particle collision. Moreover, the growth of Cu films was investigated by observing their microstructures. At the initial stage in the AD process, the impacted particles were flattened and deformed on a rough Al2O3 substrate. The continuous collision of impacted particles leads to the densification of deposited coating layers due to the plastic deformation of particles. The bonding between the Cu particles and the rough Al2O3 substrate was explained in terms of the adhesive properties on the surface roughness of Al2O3 substrates. It was revealed that the roughness of substrates was considerably associated with the mechanical interlocking between Cu particles and rough Al2O3 substrate.

  19. Characteristics and relevant remote sources of black carbon aerosol in Shanghai

    NASA Astrophysics Data System (ADS)

    Zha, Shuping; Cheng, Tiantao; Tao, Jun; Zhang, Renjian; Chen, Jianmin; Zhang, Yunwei; Leng, Chunpeng; Zhang, Deqin; Du, Jianfei

    2014-01-01

    Black carbon (BC) aerosol was measured continuously at an urban site in Shanghai (31°18‧N, 121°30‧E) from January 2011 to January 2012, and the characteristics and relevant remote sources of BC were examined. Daily BC concentrations varied within the range of 0.3-11.4 μg m- 3 with an annual average of 2.3 μg m- 3. Comparably, monthly BC concentrations were usually high in the dry season (November-April) but low in the wet season (May-October). Hourly BC showed a similar diurnal pattern with two peaks, one at 7:00-9:00 LT and another at 19:00-21:00 LT, in the four seasons. BC level was always relatively higher during daytime than nighttime. There also existed a workday/weekend difference of BC due to anthropogenic activities. The correlation analyses between BC and meteorological factors indicated that (1) wind speed was an important contributor to BC diffusion in the boundary atmosphere, (2) atmospheric visibility was not highly sensitive to BC, and (3) northwesterly, westerly and southwesterly wind directions related closely to BC. The increase of BC is likely associated with fossil fuel combustion during the winter heating period and agricultural waste burning over the surrounding areas during the summer harvest period, as well as the air masses originating from and/or transiting through these regions.

  20. Climatology and Characteristics of In-situ Aerosol Optical Properties in the Arctic

    NASA Astrophysics Data System (ADS)

    Schmeisser, L.; Ogren, J. A.; Sharma, S.; Asmi, E.; Bergin, M. H.; Jefferson, A.; Andrews, E.; Tunved, P.; Backman, J.; Starkweather, S.

    2015-12-01

    Within the Arctic, climate forcers like atmospheric aerosols are important contributors to the observed warming and environmental changes in the region. Quantifying the forcing by aerosols in the Arctic is especially difficult, given short aerosol lifetimes, annual variability in illumination and surface albedo, stratified atmospheric conditions, complex feedbacks, and long-range aerosol transport. However, in-situ surface measurements of Arctic aerosol optical properties can be used to constrain variability of light scattering and absorption, identify potential particle sources, and help evaluate the resulting forcing. Data from six WMO Global Atmosphere Watch stations are presented: Alert, Canada (ALT); Barrow, Alaska (BRW); Pallas, Finland (PAL); Summit, Greenland (SUM); Tiksi, Russia (TIK); and Zeppelin Mountain, Norway (ZEP). These sites contribute to the International Arctic System for Observing the Atmosphere (IASOA), which facilitates Arctic-wide data collection and analysis. Climatologies of aerosol optical properties from each station show differences in magnitude and variability of observed parameters. For example, Figure 1 presents the annual cycle of aerosol light scattering at 550 nm at each site for 2012-2014, with most stations (ALT, BRW, TIK, ZEP) experiencing maximum scattering in winter/spring, while SUM and PAL exhibit minimum scattering in the winter. The observed range in scattering across these sites is large (almost an order of magnitude) - SUM has the lowest annual median scattering at 0.82 Mm-1 while BRW has the highest at 6.9 Mm-1. A closer look at systematic variability between optical properties at each station, as well as site back trajectories, suggest differences in aerosol processes, sources and transport. The development of consistent climatologies and additional analyses like the ones presented here can help provide a better understanding of trans-Arctic aerosol variability, which can be an asset for improving aerosol models in

  1. A Global Modeling Study on Carbonaceous Aerosol Microphysical Characteristics and Radiative Effects

    NASA Technical Reports Server (NTRS)

    Bauer, S. E.; Menon, S.; Koch, D.; Bond, T. C.; Tsigaridis, K.

    2010-01-01

    Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, indirect and semi-direct aerosol effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative effects. Our best estimate for net direct and indirect aerosol radiative flux change between 1750 and 2000 is -0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative flux change can vary between -0.32 to -0.75 W/m2 depending on these carbonaceous particle properties at emission. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Absorption of black carbon aerosols is amplified by sulfate and nitrate coatings and, even more strongly, by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative fluxeswhen sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to a reduction in positive radiative flux.

  2. Marine Primary Aerosol in the Mediterranean atmosphere: physical and chemical properties from a mesocosm study

    NASA Astrophysics Data System (ADS)

    D'anna, B.; Sellegri, K.; Charriere, B.; Sempere, R.; Mas, S.; George, C.; Meme, A.; R'Mili, B.; Schwier, A. N.; Rose, C.

    2013-12-01

    m. The hygroscopic properties were investigated by a CCN device. On-line chemical analysis of the sub-micrometer fraction was performed by a c-TOF-AMS. Off-line analysis of the SSA generated included TEM-EDX , LC-MS and IC, Thermo-optical analysis of EC-OC. The objective of the present study is to investigate the influence of water chemical and biological composition and biological activity on physical and chemical properties of the primary generated aerosol.

  3. OZONE-ISOPRENE REACTION: RE-EXAMINATION OF THE FORMATION OF SECONDARY ORGANIC AEROSOL

    EPA Science Inventory

    The reaction of ozone and isoprene has been studied to examine physical and chemical characteristics of the secondary organic aerosol formed. Using a scanning mobility particle sizer, the volume distribution of the aerosol was found in the range 0.05 - 0.2 µm. The aerosol yield w...

  4. Characteristics of aerosol size distributions and chemical compositions during wintertime pollution episodes in Beijing

    NASA Astrophysics Data System (ADS)

    Liu, Zirui; Hu, Bo; Zhang, Junke; Yu, Yangchun; Wang, Yuesi

    2016-02-01

    To characterize the features of particle pollution, continuous measurements of particle number size distributions and chemical compositions were performed at an urban site in Beijing in January 2013. The particle number and volume concentration from 14 nm to 1000 nm were (37.4 ± 15.3) × 103 cm- 3 and (85.2 ± 65.6) μm3 cm- 3, respectively. N-Ait (Aitken mode) particles dominated the number concentration, whereas N-Acc (accumulation mode) particles dominated the volume concentration. Submicron particles were generally characterized by a high content of organics and SO42 -, and a low level of NO3- and Cl-. Two types of pollution episodes were observed, characterized by the "explosive growth" (EXP) and "sustained growth" (SUS) of PM2.5. Fine particles greater than 100 nm dominated the volume concentration during the ends of these pollution episodes, shifting the maximum of the number size distribution from 60 nm to greater than 100 nm in a few hours (EXP) or a few days (SUS). Secondary transformation is the main reason for the pollution episodes; SO42 -, NO3- and NH4+ (SNA) accounted for approximately 42% (EXP) and greater than 60% (SUS) of the N-Acc particle mass increase. The size distributions of particulate organics and SNA varied on timescales of hours to days, the characteristics of which changed from bimodal to unimodal during the evolution of haze episodes. The accumulation mode (peaking at approximately 500-700 nm) was dominated by organics that appeared to be internally mixed with nitrate or sulfate. The sulfate was most likely formed via heterogeneous reactions, because the SOR was constant under dry conditions (RH < 50%) and began to increase when RH > 50%, suggesting an important contribution from heterogeneous reactions with abundant aerosol water under wet conditions. Finally, the correlations between [NO3-]/[SO42 -] and [NH4+]/[SO42 -] suggest that the homogenous reaction between HNO3 and NH3 dominated the formation of nitrate under conditions of

  5. Determining the basic characteristics of aerosols suitable for studies of deposition in the respiratory tract.

    PubMed

    Legáth, L; Naus, A; Halík, J

    1988-01-01

    Studies of aerosol particle deposition in the respiratory tract requires experimental inhalation of artificial model aerosols. The paper formulates some of the most important requirements for the properties of such aerosols. Several suitable fractions were prepared as part of a research project dealing with the use of microporous polymers for diagnostic purposes. 5 fractions of the polymer designated G-gel 60 with the particle size as stated by the manufacturer, ranging from 3 to 7 micron were evaluated using a 16-channel particle dispersity analyzer HIAC/ROYCO MT 3210 with the sensor 1200 and operated by a microprocessor, the equipment being coupled to an APPLE IIe computer. G-gel 60 particles introduced into the aerosol were characterized by the parameters CMAD, MMAD and sg both numerically and graphically. The measurement procedure was found to be very sensitive with respect to all fractions in evaluating the subtile differences between different lot numbers of the aerosol. G-gel 60 fractions characterized both numerically and graphically were compared with the known aerosols from paraffin oil and atmospheric air. The equipment MT 3210 enables prompt determination of the percentages of aerosol particles distribution by size class. The authors conclude that the procedure, both in its numerical and graphical versions, is particularly suitable for the diagnosis of aerosol particles deposition in the respiratory tract, offering a new application for HIAC/ROYCO in the field of medicine. In evaluating atmospheric aerosol in exhaled air, the number of particles was found to be below that in inhaled air, the difference being dependent on the choice of investigation methods. Percentual distribution of deposited particles following one minute ventilation proved to be at its maximum, as regards atmospheric aerosol, in the 0.30-0.50 micron range. The deposition curve was similar to already published curves, being characterized by an S-shaped pattern with maximum deposition

  6. Aerosols in the arid southwestern United States - Measurements of mass loading, volatility, size distribution, absorption characteristics, black carbon content, and vertical structure to 7 km above sea level

    NASA Astrophysics Data System (ADS)

    Pinnick, R. G.; Fernandez, G.; Martinez-Andazola, E.; Hinds, B. D.; Hansen, A. D. A.; Fuller, K.

    1993-02-01

    A variety of methods and sensors including quartz fiber filter samplers, hi-vol samplers, ground-based and aircraft-mounted light-scattering aerosol counters, an aerosol counter equipped with a heated inlet, and an aethalometer are used to determine near-surface and lower tropospheric aerosol characteristics at several remote sites near Orogrande, New Mexico. The results of these measurements, which were taken sporadically over the last 15 yr, suggest that regardless of season, aerosol consists of two modes - a submicron fraction composed primarily of ammonium/acid sulfates and elemental black carbon and a supermicron fraction composed mainly of quartz and clay minerals of soil origin. Limited aircraft measurements in the lowest few kilometers of the troposphere reveal a well-mixed aerosol for a neutral atmospheric condition, and a significant decrease in aerosol concentration with altitude for a stable atmospheric condition.

  7. Measurement of nuclear-physical characteristics of radionuclides

    SciTech Connect

    Geidel'man, A.M.; Egorov, Yu.S.; Nedovesov, V.G.; Shchukin, G.E.

    1987-08-01

    This article provides the revised data for the nuclear-physical characteristics (NPC) measurements of seven radionuclides: /sup 238/Pu, /sup 239/Pu, /sup 55/Fe, /sup 125m/Te, /sup 119m/Sn, /sup 75/Se, and /sup 120/Tm. These radionuclides are widely used in the preparation of various radionuclide products, standard sources of ionizing radiation, and standard solutions. The emission characteristics data for the nuclides may be used for calibration of semiconductor spectrometers with regard to energy and efficiency.

  8. On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Wang, M.; Ghan, S. J.; Ding, A.; Wang, H.; Zhang, K.; Neubauer, D.; Lohmann, U.; Ferrachat, S.; Takeamura, T.; Gettelman, A.; Morrison, H.; Lee, Y. H.; Shindell, D. T.; Partridge, D. G.; Stier, P.; Kipling, Z.; Fu, C.

    2015-09-01

    Aerosol-cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (ω500), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascend (ω500 < -25 hPa d-1) and low clouds (stratocumulus and trade wind cumulus) where the models differ most. Shortwave aerosol indirect forcing is also found to differ significantly among different regimes. Shortwave aerosol indirect forcing in ascending regimes is as large as that in stratocumulus regimes, which indicates that regimes with strong large-scale ascend are as important as stratocumulus regimes in studying AIE. It is further shown that shortwave aerosol indirect forcing over regions with high monthly large-scale surface precipitation rate (> 0.1 mm d-1) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes than that globally, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.

  9. On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models

    NASA Astrophysics Data System (ADS)

    Zhang, Shipeng; Wang, Minghuai; Ghan, Steven J.; Ding, Aijun; Wang, Hailong; Zhang, Kai; Neubauer, David; Lohmann, Ulrike; Ferrachat, Sylvaine; Takeamura, Toshihiko; Gettelman, Andrew; Morrison, Hugh; Lee, Yunha; Shindell, Drew T.; Partridge, Daniel G.; Stier, Philip; Kipling, Zak; Fu, Congbin

    2016-03-01

    Aerosol-cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (ω500), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascent (ω500 < -25 hPa day-1) and low clouds (stratocumulus and trade wind cumulus) where the models differ most. Shortwave aerosol indirect forcing is also found to differ significantly among different regimes. Shortwave aerosol indirect forcing in ascending regimes is close to that in subsidence regimes, which indicates that regimes with strong large-scale ascent are as important as stratocumulus regimes in studying AIE. It is further shown that shortwave aerosol indirect forcing over regions with high monthly large-scale surface precipitation rate (> 0.1 mm day-1) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes compared to the uncertainty in its global mean values, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.

  10. Temporal variability in Chemical and Stable isotopic characteristics of ambient bulk aerosols over a coastal environment of India

    NASA Astrophysics Data System (ADS)

    Agnihotri, R.; Karapurkar, S. G.; Sarma, V. V.; Praveen, P.; Kumar, M. D.

    2012-12-01

    Atmospheric carbonaceous aerosols are known to influence regional biogeochemical cycles of carbon (C) and nitrogen (N) in addition to regional radiation budgets. Owing to multiplicity of primary sources of natural and anthropogenic origin, their detailed chemical and isotopic characterization can greatly help in source apportionment and identifying secondary processes. From the roof of NIO-Goa (India) [15.46οN, 73.8oE; at ~55.8 MASL], atmospheric bulk aerosols (n=22) were collected on Quartz filters, from 2009 December to January 2011 covering entire 2010 (except monsoon period) to investigate temporal variability in their chemical and isotopic characteristics of the carbonaceous fraction i.e. TC, TOC and TN mass concentrations and their stable isotopic ratios (δ13CTC, δ13CTOC and δ15NTN). Both δ13CTC and δ13CTOC varied in narrow ranges (-24.9±1.1‰, -25.7±0.9‰ respectively), but significant differences were observed between the two during pre-monsoon months (as high as 2.3‰), possibly due to mixing of inorganic mineral dust. δ15NTN values showed a wide range of variability (average = 13.6±7.2‰), with significantly lower values (~2-5‰; as reported earlier by Agnihotri et al. 2011) during pre-monsoon period compared to those during winter (as high as ~26‰). Using δ13CTC values and two end-member mixing model (assuming δ13C of marine and continental carbon as -21 and -27‰ respectively), the average marine carbon fraction for Goa aerosols was estimated as 36±18.5%, significantly higher than reported for Chennai aerosols (~19%) (Pavuluri et al., 2011), but close to the reported average for marine aerosols at Bermuda (38%) (Turekian et al., 2003). Chemical and isotopic characteristics of ambient aerosols over Goa along with contemporaneous meteorological data indicate that winter aerosols contain significant proportion of carbonaceous fraction originated from biomass burning and other anthropogenic activities carried out in northern parts of

  11. Long-term trends in aerosol optical characteristics in the Po Valley, Italy

    NASA Astrophysics Data System (ADS)

    Putaud, J. P.; Cavalli, F.; Martins dos Santos, S.; Dell'Acqua, A.

    2014-09-01

    Aerosol properties have been monitored by ground-based in situ and remote sensing measurements at the station for atmospheric research located in Ispra, on the edge of the Po Valley, for almost one decade. In situ measurements are performed according to Global Atmosphere Watch recommendations, and quality is assured through the participation in regular inter-laboratory comparisons. Sun-photometer data are produced by the Aerosol Robotic Network (AERONET). Data show significant decreasing trends over the 2004-2010 period for a number of variables, including particulate matter (PM) mass concentration, aerosol scattering, backscattering and absorption coefficients, and aerosol optical thickness (AOT). In situ measurement data show no significant trends in the aerosol backscatter ratio, but they do show a significant decreasing trend of about -0.7 ± 0.3% yr-1 in the aerosol single scattering albedo (SSA) in the visible light range. Similar trends are observed in the SSA retrieved from sun-photometer measurements. Correlations appear between in situ PM mass concentration and aerosol scattering coefficient, on the one hand, and elemental carbon (EC) concentration and aerosol absorption coefficient, on the other hand. However, no increase in the EC / PM ratio was observed, which could have explained the decrease in SSA. The application of a simple approximation to calculate the direct radiative forcing by aerosols suggests a significant diminution in their cooling effect, mainly due to the decrease in AOT. Applying the methodology we present to those sites, where the necessary suite of measurements is available, would provide important information to inform future policies for air-quality enhancement and fast climate change mitigation.

  12. Aerosol chemical characteristics of a mega-city in Southeast Asia (Dhaka-Bangladesh)

    NASA Astrophysics Data System (ADS)

    Salam, Abdus; Bauer, Heidi; Kassin, Karin; Mohammad Ullah, Shah; Puxbaum, Hans

    Elemental carbon (EC), organic carbon (OC), organic acids, major inorganic ions and trace elements were determined in aerosol samples collected under pre-monsoon conditions (March-April 2001) in Dhaka (Bangladesh). Using the Fe content of the aerosol to reconstruct the aerosol mass from soil-type mineralic material, a mass balance of the Dhaka aerosol was achieved. From this follows that on the average around 76% of the aerosol is from soil-type material, around 18% of carbonaceous material, and around 6% soluble ions and trace elements (without iron) <0.3%. Enrichment factors (Fe as a reference element) indicated that coal fly ash is a likely main source for Cd, Pb and Zn in the Dhaka aerosol, while As appears to be of geogenic origin. Organic acids contributed only 0.72% C to OC and were much less abundant relative to OC than at European sites. The trace elements levels in Dhaka were much lower than at comparable Southeast Asian mega-cities (e.g. Lahore, Pakistan), but considerably higher than reported for European and US cities under present day conditions. The correlation between EC and OC was quite high ( R2=0.81) indicating a potential joint source of emission for carbonaceous aerosols. The EC/total carbon (TC) and K/EC ratios indicated that biomass combustion was not a main contributor to EC in Dhaka, which implicates that fossil fuel combustion is the major contributor to EC levels in the Dhaka aerosol. The differences in the EC/TC and K/EC ratios in the three mega-cities in Southeast Asia (data available from Dhaka, Bangladesh; Lahore, Pakistan; and Mumbai, India) indicate that the aerosol source mix in Southeast Asian cities varies considerably at a national or even regional scale.

  13. Distinguishing molecular characteristics of aerosol water soluble organic matter from the 2011 trans-North Atlantic US GEOTRACES cruise

    NASA Astrophysics Data System (ADS)

    Wozniak, A. S.; Willoughby, A. S.; Gurganus, S. C.; Hatcher, P. G.

    2014-03-01

    The molecular characteristics of aerosol organic matter (OM) determines to a large extent its impacts on the atmospheric radiative budget and ecosystem function in terrestrial and aquatic environments, yet the molecular details of aerosol OM from different sources are not well established. Aerosol particulate samples having North American-influenced, North African-influenced, and marine (minimal recent continental influence) air mass back trajectories were collected as part of the 2011 trans-North Atlantic US GEOTRACES cruise and analyzed for their water soluble OM (WSOM) molecular characteristics using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Principal component analysis (PCA) separated the samples into five groups defined by distinct molecular formula characteristics. An abundance of nitrogen containing compounds with molecular formulas consistent with amino acid derivatives defined the two samples comprising the Primary Marine group suggesting a primary marine biological source to their WSOM in spite of their North American-influenced air mass trajectories. A second group of samples (Aged Marine) having primarily marine air mass trajectories was characterized by an abundance of low O / C (0.15-0.45) sulfur containing compounds consistent with organosulfate compounds formed via secondary aging reactions in the atmosphere. Several samples having North American-influenced air mass trajectories formed another group again characterized by organosulfate and nitrooxyorganosulfate type compounds with higher O / C ratios (0.5-1.0) than the Aged Marine samples reflecting the combustion influence from the North American continent. All the samples having North African-influenced air mass trajectories grouped together in the PCA and were characterized by a lack of heteroatom (N, S, P) containing molecular formulas covering a wide O / C range (0.15-0.90) reflecting the desert source of this WSOM. The two marine groups showed

  14. Distinguishing molecular characteristics of aerosol water soluble organic matter from the 2011 trans-North Atlantic US GEOTRACES cruise

    NASA Astrophysics Data System (ADS)

    Wozniak, A. S.; Willoughby, A. S.; Gurganus, S. C.; Hatcher, P. G.

    2014-08-01

    The molecular characteristics of aerosol organic matter (OM) determines to a large extent its impacts on the atmospheric radiative budget and ecosystem function in terrestrial and aquatic environments, yet the OM molecular details of aerosols from different sources are not well established. Aerosol particulate samples with North American-influenced, North African-influenced, and marine (minimal recent continental influence) air mass back trajectories were collected as part of the 2011 trans-North Atlantic US GEOTRACES cruise and analyzed for their water soluble OM (WSOM) molecular characteristics using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Principal component analysis (PCA) separated the samples into five groups defined by distinct molecular formula characteristics. An abundance of nitrogen containing compounds with molecular formulas consistent with amino acid derivatives defined the two samples comprising the primary marine group (henceforth referred to as Primary Marine), which suggest a primary marine biological source to their WSOM in spite of their North American-influenced air mass trajectories. A second group of samples (aged marine, henceforth referred to as Aged Marine) with marine air mass trajectories was characterized by an abundance of low O / C (0.15-0.45) sulfur containing compounds consistent with organosulfate compounds formed via secondary aging reactions in the atmosphere. Several samples having North American-influenced air mass trajectories formed another group again characterized by organosulfate and nitrooxyorganosulfate type compounds with higher O / C ratios (0.5-1.0) than the Aged Marine samples reflecting the combustion influence from the North American continent. All the samples with North African-influenced air mass trajectories were grouped together in the PCA and were characterized by a lack of heteroatom (N, S, P) containing molecular formulas covering a wide O / C range (0

  15. Composition and Characteristics of Aerosols in the Southern High Plains of Texas (USA)

    SciTech Connect

    Gill, Thomas E.; Stout, John E.; Peinado, Porfirio

    2009-03-10

    Aerosol samples on polycarbonate filters were collected daily for several years in the Southern High Plains region of western Texas. Selected samples representing a variety of size modes, locations, and air quality conditions were analyzed by PIXE. Silicon and other crustal elements dominated during dust storms and in the coarse mode; sulfur dominated during anthropogenic pollution episodes and in the fine mode. A mixture of both aerosol types was present even during 'clear' conditions. The Al/Si ratio in dust events increases with wind speed. These data provide an initial assessment of aerosol chemistry in the West Texas plains.

  16. Interrelationships Between Aerosol Characteristics and Light Scattering During Late-winter in a Eastern Mediterranean Arid Environment

    NASA Technical Reports Server (NTRS)

    Ichoku, C.; Andreae, M. O.; Meixner, F. X.; Schebeske, G.; Formenti, P.; Maenhaut, W.; Cafmeyer, J.; Ptasinski, J.; Karnieli, A.; Orlovsky, L.

    1999-01-01

    An intensive field campaign involving measurement of various aerosol physical, chemical, and radiative properties was conducted at Sde Boker in the Negev Desert of Israel, from 18 February to 15 March 1997. Nephelometer measurements gave average background scattering coefficient values of about 25 M/m at 550 nm wavelength, but strong dust events caused the value of this parameter to rise up to about 800 M/m Backscattering fractions did not depend on aerosol loading, and generally fell in the range of 0.1 to 0.25, comparable to values reported for marine and Arctic environments. Chemical analysis of the aerosol revealed that, in the coarse size range (2 - 10 micrometer equivalent aerodynamic diameter (EAD)), calcium (Ca) was by far the most abundant element followed by silicon (Si), both of which are indicators for mineral dust. In the fine size fraction (< 2 micrometers EAD), sulfur (S) generally was the dominant element, except during high dust episodes when Ca and Si were again the most abundant. Furthermore, fine black carbon (BC) correlates with S, suggesting that they may have originated from the same sources or source regions. An indication of the short-term effect of aerosol loading on radiative forcing was provided by measurements of global and diffuse solar radiation, which showed that during high turbidity periods (strong dust events) almost all of the solar radiation reaching the area is scattered or absorbed.

  17. Spatial and Temporal Characteristics of Aerosols from Collection 6 Aqua and Terra MODIS e-Deep Blue Products

    NASA Astrophysics Data System (ADS)

    Bettenhausen, C.; Hsu, N. Y. C.; Sayer, A. M.; Lee, J.; Carletta, N.

    2015-12-01

    Aerosols continue to attract a significant amount of attention from researchers worldwide due to their extensive effects on Earth's climate, ecology, public health, and even energy production. In order to truly understand these effects, a long, stable, and well-calibrated data record is required. Since 2000 and 2002, the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the Terra and Aqua satellites together with the e-Deep Blue aerosol retrieval algorithm have been providing such a data record. After a multi-year development effort, the production of both Aqua and Terra MODIS Collection 6 (C6) atmosphere products successfully completed earlier this year and the data was released to the public shortly thereafter. The C6 Deep Blue products (now enhanced Deep Blue or e-Deep Blue) have been significantly improved over the previous Collection 5.1 version. In this poster we provide an overview of the latest C6 e-Deep Blue products and the improvements implemented since the previous collection including coverage over dark surfaces and updates to the Terra calibration. Validation results utilizing Aerosol Robotic Network (AERONET) data are also summarized. We then use the C6 e-Deep Blue products from both Aqua and Terra to explore the spatial characteristics in addition to the seasonal and inter-annual variability of aerosols on both regional and global scales. We also use this as an opportunity to compare these results and investigate any differences found between the two instruments.

  18. Anthropometrics, Physical Performance, and Injury Characteristics of Youth American Football

    PubMed Central

    Caswell, Shane V.; Ausborn, Ashley; Diao, Guoqing; Johnson, David C.; Johnson, Timothy S.; Atkins, Rickie; Ambegaonkar, Jatin P.; Cortes, Nelson

    2016-01-01

    Background: Prior research has described the anthropometric and physical performance characteristics of professional, collegiate, and high school American football players. Yet, little research has described these factors in American youth football and their potential relationship with injury. Purpose: To characterize anthropometric and physical performance measures, describe the epidemiology of injury, and examine the association of physical performance measures with injury among children participating within age-based divisions of a large metropolitan American youth football league. Study Design: Case-control study; Level of evidence, 3. Methods: Demographic, anthropometric, and physical performance characteristics and injuries of 819 male children were collected over a 2-year period (2011-2012). Injury data were collected by the league athletic trainer (AT) and coaches. Descriptive analysis of demographic, anthropometric, and physical performance measures (40-yard sprint, pro-agility, push-ups, and vertical jump) were conducted. Incidence rates were computed for all reported injuries; rates were calculated as the number of injuries per 1000 athlete-exposures (AEs). Multinomial logistic regression was used to identify whether the categories of no injury, no-time-loss (NTL) injury, and time-loss (TL) injury were associated with physical performance measures. Results: Of the 819 original participants, 760 (92.8%) completed preseason anthropometric measures (mean ± SD: age, 11.8 ± 1.2 years; height, 157.4 ± 10.7 cm; weight, 48.7 ± 13.3 kg; experience, 2.0 ± 1.8 years); 640 (78.1%) players completed physical performance measures. The mean (±SD) 40-yard sprint and pro-agility measures of the players were 6.5 ± 0.6 and 5.7 ± 0.5 seconds, respectively; the number of push-ups and maximal vertical jump height were 16.5 ± 9.3 repetitions and 42.3 ± 8.4 cm, respectively. Players assigned to different teams within age divisions demonstrated no differences in

  19. Aerosol characteristics and sources for the Amazon basin during the wet season

    SciTech Connect

    Artaxo, P. ); Maenhaut, W. ); Storms, H.; Van Grieken, R. )

    1990-09-20

    Fine (< 2.0 {mu}m) and coarse (2.0 - 15 {mu}m) aerosol fractions were collected using stacked filter units, at three sites under the forest canopy and at three levels of a tower inside the jungle. Particle-induced x-ray emission (PIXE) was used to measure concentrations Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, and Pb. Morphological and trace element measurements of individual particles were carried out by automated electron probe x-ray microanalysis. Gravimetric analysis was performed to obtain the fine and coarse aerosol mass concentration. The concentrations of soil dust related elements (Al, Si, Ti, Fe, Mn) were 5 times larger in the wet season compared to the 1985 ABLE 2A dry season experiment. Biogenic aerosol related elements in the fine fraction showed lower concentrations in the wet season. Fine aerosol mass concentration averaged only 2.1 {plus minus} 0.7 {mu}g m{sup {minus}3}, while the average coarse mass concentration was 6.1 {plus minus} 1.8 {mu}g m{sup {minus}3}. Sulfur concentrations averaged 76 {plus minus} 14 ng m{sup {minus}3} in the fine fraction and 37 {plus minus} 9 ng m{sup {minus}3} in the coarse fraction. Only two factors explained about 90% of the data variability for the fine and coarse aerosol fractions. These were soil dust (represented mainly by Al, Si, Ti, Mn, and Fe) and biogenic aerosol (represented by K, P, Cl, S, Zn, and the aerosol mass concentration). Biogenic particles account for 55-95% of the airborne concentrations and consisted of leaf fragments, pollen grains, fungi, algae, and other types of particles. It is possible that biogenic particles can play an important role in the global aerosol budget and in the global biogeochemical cycles of various elements.

  20. Hygroscopicity and CCN activity of atmospheric aerosol particles and their relation to organics: Characteristics of urban aerosols in Nagoya, Japan

    NASA Astrophysics Data System (ADS)

    Kawana, Kaori; Nakayama, Tomoki; Mochida, Michihiro

    2016-04-01

    The size-resolved distributions of hygroscopic growth factor g and the ratios of cloud condensation nuclei (CCN) to condensation nuclei of atmospheric aerosols were investigated in Nagoya, Japan. The average of the distributions of g at 85% relative humidity was bimodal. The size-resolved mean κ derived from g showed an increasing trend with diameter: 0.17-0.33 at 24-359 nm. The κ values calculated from CCN activation curves were 37% higher than those derived from g. Only 9% of the 37% difference is explained by the difference in the κ of inorganics under subsaturated and supersaturated conditions, suggesting a contribution of organics to the remaining 28% difference. The size-averaged κ of organics (κorg) was calculated as 0.14 and 0.19 by two different methods. The number fractions of CCN predicted from the hygroscopicity data over the range of 24-359 nm are loosely consistent with those observed if the size- and time-averaged g is applied to all particles (differences: -30% to +10%). This consistency improves if size- and time-resolved g and g distribution are used (differences: -19% to -3%). Whereas the number fractions of CCN predicted from the composition data are greatly underestimated if organics are assumed to be insoluble (differences: -64% to -45%), they are more consistent if κorg of 0.14 or 0.19 is applied (differences: -10% to +14%). The results demonstrate the importance of the dependence of the g of particles on time and particle size and the hygroscopicity of organics for CCN number concentrations in the urban atmosphere.

  1. Regional Aerosol Optical Depth Characteristics from Satellite Observations: ACE-1, TARFOX and ACE-2 Results

    NASA Technical Reports Server (NTRS)

    Durkee, P. A.; Nielsen, K. E.; Smith, P. J.; Russell, P. B.; Schmid, B.; Livingston, J. M.; Holben, B. N.; Tomasi, C.; Vitale, V.; Collins, D.

    1999-01-01

    Analysis of the aerosol properties during 3 recent international field campaigns ACE-1, TARFOX and ACE-2 are described using satellite retrievals from NOAA AVHRR data. Validation of the satellite retrieval procedure is performed with airborne, shipboard, and land-based sunphotometry during ACE-2. The intercomparison between satellite and surface optical depths has a correlation coefficient of 0.93 for 630 nm wavelength and 0.92 for 860 nm wavelength, The standard error of estimate is 0.025 for 630 nm wavelength and 0.023 for 860 nm wavelength. Regional aerosol properties are examined in composite analysis of aerosol optical properties from the ACE-1, TARFOX and ACE-2 regions. ACE-1 and ACE-2 regions have strong modes in the distribution of optical depth around 0.1, but the ACE-2 tails toward higher values yielding an average of 0.16 consistent with pollution and dust aerosol intrusions. The TARFOX region has a noticeable mode of 0.2, but has significant spread of aerosol optical depth values consistent with the varied continental aerosol constituents off the eastern North American Coast.

  2. Hydrogen chloride and aerosol ground cloud characteristics resulting from Space Shuttle launches

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Cofer, W. R., III; Woods, D. C.; Maddrea, G. L., Jr.

    1984-01-01

    Airborne measurements of gaseous HCl, gaseous and aerosol HCl, particulates, relative humidity and temperature were obtained in ground clouds produced during three Space Shuttle launches. Partitioning of HCl between HCl aerosol and gaseous HCl was investigated as the solid rocket exhaust cloud diluted with ambient air to evaluate the conditions under which aerosol formation occurs in the troposphere in the presence of hygroscopic HCl vapor. Equilibrium predictions for aqueous HCl aerosol formation generally agree with the measured HCl partitioning over HCl concentrations from 0.5 to 36 ppm. HCl concentration dispersion within four cloud segments at time t (min) was evaluated using the expression C = C(0) (t to the alpha power) where C(0) varied from 145 to 2250 ppm and alpha varied from -1.14 to -1.73. Aerosol fallout from the exhaust clouds was measured with time by monitoring HCl concentrations and aerosol distributions 100 m below the cloud as it drifted away from the launch site. Significant amounts of HCl were found to be removed by fallout of particles in the 80-220 micron diameter range up to 30 min after launch.

  3. Elemental characteristics of aerosols emitted from a coal-fired heating plant

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Khandelwal, G. S.

    1978-01-01

    Size differentiated aerosols were collected downstream from a heating plant fueled with eastern coal and analyzed using particle induced X-ray emission technique. Based on aerosol masses collected in various size ranges, the aerosol size distribution is determined to be trimodal, with the three peaks centered at 0.54 microns, 4.0 microns, and 11.0 microns, respectively. Of the various trace elements present in the aerosols, sulphur is the only element that shows very strong concentration in the smallest size group. Iron is strongly concentrated in the 4.0 micron group. Potassium, calcium, and titanium also exhibit stronger concentration in the 4.0 micron group than any other group. Other trace elements - vanadium, chromium, manganese, nickel, copper, and barium - are equally divided between the 0.54 microns and the 4.0 microns groups. Apparently, all of the trace elements - except S - enter aerosols during the initial formation and subsequent condensation phases in the combustion process. Excess concentration of sulphur in the 0.54 microns group can only be accounted for by recondensation of sulphur vapors on the combustion aerosols and gas-to-particle phase conversion of sulfate vapors at the stack top.

  4. Hydrogen chloride and aerosol ground cloud characteristics resulting from space shuttle launches

    NASA Astrophysics Data System (ADS)

    Sebacher, Daniel I.; Cofer, Wesley R.; Woods, David C.; Maddrea, George L.

    Airborne measurements of gaseous HCl, gaseous and aerosol HCl, particulates, relative humidity and temperature were obtained in ground clouds produced during three Space Shuttle launches. Partitioning of HCl between HCl aerosol and gaseous HCl was investigated as the solid rocket exhaust cloud diluted with ambient air to evaluate the conditions under which aerosol formation occurs in the troposphere in the presence of hygroscopic HCl vapor. Equilibrium predictions for aqueous HCl aerosol formation generally agree with the measured HCl partitioning over HCl concentrations from 0.5 to 36 ppm. HCl concentration dispersion within four cloud segments at time t (min) was evaluated using the expression C = C 0t α where C 0 varied from 145 to 2250 ppm and α varied from -1.14 to -1.73. Aerosol fallout from the exhaust clouds was measured with time by monitoring HCl concentrations and aerosol distributions 100 m below the cloud as it drifted away from the launch site. Significant amounts of HCl were found to be removed by fallout of particles in the 80-220 μm diameter range up to 30 min after launch.

  5. Physical and optical properties of aerosols over an urban location in western India: Implications for shortwave radiative forcing

    NASA Astrophysics Data System (ADS)

    Ganguly, Dilip; Jayaraman, A.

    2006-12-01

    We discuss results on implications of seasonal and interannual variabilities in aerosol parameters measured over Ahmedabad, an urban location in western India, for the regional-scale shortwave aerosol direct radiative forcing. Results on physical and optical properties of aerosols are discussed in a companion paper. A discrete ordinate radiative transfer model has been used to carry out the radiative transfer computations. Two different approaches are followed to generate spectral values of aerosol parameters required as input for the radiative transfer computations, and the estimated values are found comparable for both methods. Magnitudes of surface forcing are found to be highest during postmonsoon (-63 ± 10 W/m2), followed by dry (-54 ± 6 W/m2) and lower values during premonsoon (-41.4 ± 5 W/m2) and monsoon (-41 ± 11 W/m2) seasons. In case of TOA, radiative forcing are found to be negative during dry (-26 ± 3 W/m2) and postmonsoon (-22), while positive values are obtained during monsoon (14) and premonsoon (8). Large differences between TOA and surface forcing during monsoon and premonsoon indicate large absorption of radiant energy (˜50 W/m2) within the atmosphere during these seasons. Different properties of aerosols and differences in their vertical distribution give rise to different heating rates within the atmosphere for different seasons. Heating rates at the surface are found to be highest during postmonsoon (5.6°K/day) but decreases sharply with increase in height. Atmosphere is heated strongly at higher levels between 1 and 2 km during monsoon. Results from several sensitivity studies have emphasized the importance of solar zenith angle and other related factors in modulating the values of aerosol radiative forcing.

  6. Aerosol/cloud Base Droplet Size Distribution Characteristics and the Onset of Coalescence in Shallow and Deep Convective Clouds

    NASA Astrophysics Data System (ADS)

    Bruintjes, R. T.; Lawson, P.; Lance, S.; Axisa, D.; Woods, S.

    2014-12-01

    It is clear that aerosols contribute to the observed differences in cloud droplet size distributions between maritime and continental and between non-polluted and polluted convection. In addition, other factors such as cloud base temperature, boundary layer depth, thermodynamic profile (updraft speeds) that vary between land and ocean regions, could also be contributing to the observed differences or acting in concert with aerosol effects. In addition, the initial cloud droplet spectra at cloud base to a large extent determines the microphysical processes of precipitation formation (water and ice) at higher levels in the clouds and thus the vertical transport of aerosols and gases in deep convective clouds. During the 2013 NASA SEAC4RS field campaign we have collected a large amount of microphysical data in both shallow and deep convective clouds. This data will be compared to data from other field campaigns to detect specific characteristics of the cloud base droplet size distribution and relate it to onset and evolution of the coalescence process in clouds. The presentation will provide a survey of the cloud droplet size distributions at cloud base in both shallow and deep convective clouds and will relate them to environmental parameters to better understand aerosol-cloud interactions and the other parameters that play a role in the onset of coalescence in convective clouds. We will relate the airborne aerosol variations (size and concentration in different environments) to the cloud droplet size distribution. Model simulations using a detailed coalescence model will be used to obtain a better understanding of the onset of the coalescence process.

  7. Influence of temperature and artificially-created physical barriers on the efficacy of synergized pyrethrin aerosol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flour mills in the United States are utilizing synergized pyrethrin aerosol for management of stored product insects. However, the dispersal of the aerosol within a facility may be hampered by barriers created from machinery and other equipment that block dispersion. Additionally, seasonal temperatu...

  8. Temporal dynamics of optical-microphysical characteristics of atmospheric aerosol at the Spitsbergen Archipelago in 2011-2014

    NASA Astrophysics Data System (ADS)

    Chernov, D. G.; Kozlov, V. S.; Panchenko, M. V.; Turchinovich, Yu. S.; Radionov, V. F.; Gubin, A. V.; Prakhov, A. N.

    2015-11-01

    In 2011-2014, the Institute of Atmospheric Optics (IAO SB RAS, Tomsk) and the Arctic and Antarctic Research Institute (AARI, St. Petersburg) conducted field investigations of the near-ground aerosol characteristics near Barentsburg (Spitsbergen Archipelago) in the spring and summer seasons. The particle number density in the size range 0.3-20 μm, size distribution of particles, and mass concentrations of aerosol and black carbon were measured round-the-clock every hour with Grimm 1.108 and 1.109; and AZ-10 optical counters. The mass concentration of black carbon was measured by the MDA-02 aethalometer developed by the IAO SB RAS. Series of observations are obtained, annual and seasonal average values and their standard deviations are estimated, and seasonal and annual dynamics of the studied parameters is analyzed. Peculiarities of the temporal dynamics of average values of the aerosol characteristics are revealed and compared with the data of observations at other stations of the Spitsbergen Archipelago and in different regions of the Russian Arctic and Subarctic.

  9. Characteristics and composition of atmospheric aerosols in Phimai, central Thailand during BASE-ASIA

    NASA Astrophysics Data System (ADS)

    Li, Can; Tsay, Si-Chee; Hsu, N. Christina; Kim, Jin Young; Howell, Steven G.; Huebert, Barry J.; Ji, Qiang; Jeong, Myeong-Jae; Wang, Sheng-Hsiang; Hansell, Richard A.; Bell, Shaun W.

    2013-10-01

    Comprehensive measurements of atmospheric aerosols were made in Phimai, central Thailand (15.183°N, 102.565°E, elevation: 206 m) during the BASE-ASIA field experiment from late February to early May in 2006. The observed aerosol loading was sizable for this rural site (mean aerosol scattering: 108 ± 64 Mm-1; absorption: 15 ± 8 Mm-1; PM10 concentration: 33 ± 17 μg m-3), and dominated by submicron particles. Major aerosol compounds included carbonaceous (OC: 9.5 ± 3.6 μg m-3; EC: 2.0 ± 2.3 μg m-3) and secondary species (SO42-: 6.4 ± 3.7 μg m-3, NH4+: 2.2 ± 1.3 μg m-3). While the site was seldom under the direct influence of large forest fires to its north, agricultural fires were ubiquitous during the experiment, as suggested by the substantial concentration of K+ (0.56 ± 0.33 μg m-3). Besides biomass burning, aerosols in Phimai during the experiment were also strongly influenced by industrial and vehicular emissions from the Bangkok metropolitan region and long-range transport from southern China. High humidity played an important role in determining the aerosol composition and properties in the region. Sulfate was primarily formed via aqueous phase reactions, and hygroscopic growth could enhance the aerosol light scattering by up to 60%, at the typical morning RH level of 85%. The aerosol single scattering albedo demonstrated distinct diurnal variation, ranging from 0.86 ± 0.04 in the evening to 0.92 ± 0.02 in the morning. This experiment marks the first time such comprehensive characterization of aerosols was made for rural central Thailand. Our results indicate that aerosol pollution has developed into a regional problem for northern Indochina, and may become more severe as the region's population and economy continue to grow.

  10. Variation of aerosol characteristics in the detail scale of time and space

    NASA Astrophysics Data System (ADS)

    Mukai, S.; Nakata, M.; Sano, I.

    2012-04-01

    In this work, we intend to demonstrate the spatial and temporal variation of atmospheric aerosols around AERONET/Osaka site. Osaka is the second big city in Japan and a typical Asian urban area. It is well known that the aerosol distribution in Asia is complicated due to the increasing emissions of anthropogenic aerosols in association with economic growth and in addition behavior of natural dusts significantly varies with the seasons. Therefore local spatially and temporally resolved measurements of atmospheric particles in Asian urban city are meaningful. We equip various ground measurement devices of atmosphere in the campus of Kinki University (KU). The data supplied by the Cimel instrument are analyzed with a standard AERONET (Aerosol Robotics Network) processing system. It provides us with Aerosol optical thickness (AOT), the Ångström exponent and so on. We set up a PM sampler and a standard instrument of NIES/LIDAR network attached to our AERONET site. The PM sampler provides particle information about the concentrations of PM2.5, PM10 and OBC separately. In addition to the simultaneous measurements, we make observation of the air quality at several locations in the neighbour-hood using portable sun-photometers (Solar-Light Company Microtops-2). The simultaneous measurements of aerosols and numerical model simulations indicate that the spatial and temporal factors influence the characterization of atmospheric particles especially in dust event. Then we observe the air quality at such several locations within a few 10 km area from KU, as Izumi and Nara, in ordinal days and dust days. Izumi site locates near industrial area and Nara is in the east of KU beyond the mountain-Ikoma. It is found from the simultaneous measurements at these three sites that AOT at Izumi in ordinal days is the highest and Nara's lowest. It indicates that the Ikoma-mountains block off the polluted air from the west. However in dust days, AOT at Nara is as large as that at Higashi

  11. Physical characteristics of polyimide films for flexible sensors

    NASA Astrophysics Data System (ADS)

    Chang, Wen-Yang; Fang, Te-Hua; Lin, Yu-Cheng

    2008-08-01

    Physical characteristics of polyimide films, including optical, micro/nano mechanical, and thermophysical characteristics were investigated using a photometric, a nanoindentation, and a thermomechanical analyzer for applications in flexible sensors. Experimental results show that UV light cannot transmit into the polyimide films. The transmittances, with a maximum of about 86%, at VIS and near IR lights decrease with increasing PI film thicknesses. The mechanical characteristics were determined using tensile, bending moment, and nanoindentation testing. The stress-strain curve approximated bilinear characteristics, the load-unload bending moment exhibited hysteresis, and nanoindentation generated elastic energy dissipation in the loading-unloading region. Nanoindentation showed an almost uniform hardness and a reduced Young’s modulus of about 0.181±0.03 and 3.21±0.06 GPa, respectively, when the penetrating depth was more than about 2 μm. Thermophysical characteristics were greatly influenced on 8.3 and 25 μm specimens due to the higher relaxation of thin PI films. The thermal expansion remained steady when the thickness was over 50 μm. The results show that PI films have potential in flexible sensing and higher temperature fabrication.

  12. Measuring the characteristics of stratospheric aerosol layer and total ozone concentration at Siberian Lidar Station in Tomsk

    NASA Astrophysics Data System (ADS)

    Nevzorov, Aleksey; Bazhenov, Oleg; Burlakov, Vladimir; Dolgii, Sergey

    2015-11-01

    We consider the results of long-term remote optical monitoring, obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (56.5 °N, 85.0 °E). The scattering characteristics of stratospheric aerosol layer, obtained according to data of lidar measurements since 1986, are presented. We analyze the trends of changes in the total ozone (TO) content over Tomsk for the period 1996-2013 according to data of spectrophotometric measurements with employment of TOMS satellite data for the period 1979- 1994. We determined the periods of elevated content of stratospheric aerosol over Tomsk after a series of explosive eruptions of volcanoes of Pacific Ring of Fire and Iceland in 2006-2011. Since the second half of 1990s, researchers record an increasing TO trend, equaling 0.65 DU/yr for the period 1996-2013.

  13. Certain Results of Measurements of Characteristics of Stratospheric Aerosol Layer and Total Ozone Content at Siberian Lidar Station in Tomsk

    NASA Astrophysics Data System (ADS)

    Nevzorov, Aleksey; Bazhenov, Oleg; Burlakov, Vladimir; Dolgii, Sergey

    2016-06-01

    We consider the results of long-term remote optical monitoring, obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (56.5°N, 85.0°E). The scattering characteristics of stratospheric aerosol layer, obtained according to data of lidar measurements since 1986, are presented. We analyze the trends of changes in the total ozone (TO) content over Tomsk for the period 1996-2013 according to data of spectrophotometric measurements with employment of Total Ozone Mapping Spectrometer (TOMS) data for the period 1979-1994. We determined the periods of elevated content of stratospheric aerosol over Tomsk aftera series of explosive eruptions of volcanoes of Pacific Ring of Fire and Iceland in 2006-2011. Since the second half of 1990s, we record an increasing TO trend, equaling 0.65 DU/yr for the period 1996-2013.

  14. Aerosol characteristics in the UTLS region: A satellite-based study over north India

    NASA Astrophysics Data System (ADS)

    Srivastava, A. K.; Misra, A.; Kanawade, Vijay P.; Devara, P. C. S.

    2016-01-01

    Vertical profiles of aerosol backscatter coefficient and depolarization ratio, obtained from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, were studied in the upper troposphere and lower stratosphere (UTLS) region over North India (21-30° N and 72-90° E), covering the highly polluted Indo-Gangetic Plain (IGP) for one-year period from December 2011 to November 2012. An enhanced aerosol layer was observed between 15 and 18 km altitude, in the vicinity of tropopause, with a broad layer depth of about 2 km. The aerosol layer showed strong seasonal, monthly as well as day and night time variability, with a peak value of backscatter coefficient during monsoon season (˜5.54 × 10-3 sr-1 in September). The corresponding depolarization ratio indicates anisotropic (non-spherical) nature of particles. The aerosol layer was found to be highly linked with the variability in tropopause height, showing a positive correlation between tropopause height and the height of maximum backscatter coefficient (correlation coefficient of 0.8). However, it was found to be negatively correlated with the integrated backscatter coefficient (IBC), with a correlation coefficient of 0.3. We further analyzed outgoing long-wave radiation (OLR) data during the study period to investigate the link between the observed enhanced aerosol layer in the UTLS region and prevailing deep convective activities over the study region. Low values of OLR during monsoon (about 214 W m-2) indicate the occurrence of deep convection over this region, which may cause a large-scale circulation-driven vertical transport of boundary-layer pollution into the atmosphere of UTLS region. Results may have potential implications for better understanding and assessing the chemical and radiative impacts of these aerosols in the tropical UTLS region.

  15. 2014 iAREA campaign on aerosol in Spitsbergen - Part 1: Study of physical and chemical properties

    NASA Astrophysics Data System (ADS)

    Lisok, J.; Markowicz, K. M.; Ritter, C.; Makuch, P.; Petelski, T.; Chilinski, M.; Kaminski, J. W.; Becagli, S.; Traversi, R.; Udisti, R.; Rozwadowska, A.; Jefimow, M.; Markuszewski, P.; Neuber, R.; Pakszys, P.; Stachlewska, I. S.; Struzewska, J.; Zielinski, T.

    2016-09-01

    This paper presents the results of measurements of aerosol physical and chemical properties during iAREA2014 campaign that took place on Svalbard between 15th of Mar and 4th of May 2014. With respect to field area, the experiment consisted of two sites: Ny-Ålesund (78°55‧N, 11°56‧E) and Longyearbyen (78°13‧N, 15°33‧E) with further integration of Aerosol Robotic Network (AERONET) station in Hornsund (77°00‧N, 15°33‧E). The subject of this study is to investigate the in-situ, passive and active remote sensing observations as well as numerical simulations to describe the temporal variability of aerosol single-scattering properties during spring season on Spitsbergen. The retrieval of the data indicates several event days with enhanced single-scattering properties due to the existence of sulphate and additional sea-salt load in the atmosphere which is possibly caused by relatively high wind speed. Optical results were confirmed by numerical simulations made by the GEM-AQ model and by chemical observations that indicated up to 45% contribution of the sea-salt to a PM10 total aerosol mass concentration. An agreement between the in-situ optical and microphysical properties was found, namely: the positive correlation between aerosol scattering coefficient measured by the nephelometer and effective radius obtained from laser aerosol spectrometer as well as negative correlation between aerosol scattering coefficient and the Ångstrom exponent indicated that slightly larger particles dominated during special events. The in-situ surface observations do not show any significant enhancement of the absorption coefficient as well as the black carbon concentration which might occur during spring. All of extensive single-scattering properties indicate a diurnal cycle in Longyearbyen, where 21:00-5:00 data stays at the background level, however increasing during the day by the factor of 3-4. It is considered to be highly connected with local emissions originating

  16. Analysis of Aerosol Physical and Chemical Properties on the Coast of the Japanese Sea (Tango peninsula) during ACE-Asia

    NASA Astrophysics Data System (ADS)

    Tohno, S.; Hoeller, R.; Ito, K.; Onishi, Y.; Ma, C. J.; Kasahara, M.; Cahill, T. A.; Cliff, S.

    2001-12-01

    During springtime the Japanese archipelago is periodically influenced by haze events originating from the Asian continent. The sources of these materials include both anthropogenic and natural aerosol, including the well-known yellow sand (Kosa) events, which can be recognized at places as far as Hawaii and the west coast of the United States. But there is also strong evidenced, which we want to support in this study, that these Kosa events are accompanied by strongly absorbing material as well as sulfates and organics. The springtime of 2001 was characterized by several strong dust events, which happened to be during the international ACE-Asia campaign. We participated in the ACE observation network by setting up a monitoring station during the period March 19 to April 6, 2001 for the measurement of aerosol optical, physical and chemical properties as well as observations of sky radiation. The measurement site is located on the coast of the Japanese Sea (Tango Peninsula, Kyoto Prefecture). Tango was chosen as an observation site, since it is relatively unpolluted and can therefore serve as a background site for studies of the direct impact of the mainland Asian outflow on the western Pacific area. The purpose of this work is to perform local and column closure experiments on aerosol properties, and to distinguish the anthropogenic part of the aerosol from the natural one. For this purpose, backward air-mass trajectories are calculated to identify potential sources of the observed aerosol. For measurements of aerosol mass-size distributions we used 12-stage low-pressure impactors, which were subsequently analyzed for elemental and ionic concentrations by PIXE, and Ion-chromatography, respectively. In addition, to get both the necessary time- and size-resolution, a DRUM sampler was operated with continuous collection and analysis for mass and optical transmission from 320 nm to 850 nm. Analysis is scheduled by synchrotron-XRF to < 0.1 ng/m3 for trace elemental

  17. Hygroscopic Characteristics of Organic Laden Ambient Aerosols in Yosemite National Park

    NASA Astrophysics Data System (ADS)

    Malm, W. C.; Day, D. E.; Kreidenweis, S. M.; Collett, J. L.; Carrico, C. M.; Lee, T.; Bench, G.; Carrillo, J.

    2003-12-01

    Water absorption by inorganic compounds can be modeled with some degree of certainty; however, water uptake by ambient organic aerosols remains speculative. To improve the understanding of organic hygroscopicity, an aerosol characterization study was conducted at Yosemite National Park, California, starting in July and ending in the first week of September 2002. High time resolution measurement (15-minute time increments) of PM2.5 ionic species (Cl-, SO42-, NO3-, Na+, NH4+, K+, Mg2+, and Ca2+) were measured using PILS (Particle-Into-Liquid-System)/IC (Ion Chromatography). Commercially available annular denuders and a PM2.5 cyclone (URG) were used upstream of the PILS/IC to remove particles greater than 2.5 μm and acidic and basic gases. A dual wavelength aethalometer and an R&P particulate carbon monitor were used to measure carbon on a semi-continuous basis while a DRUM sampler allowed for semi-continuous estimates of concentrations of elements associated with crustal material. Standard IMPROVE type samplers were used to measure 24-hr integrated samples of these same aerosols. Two nephelometers operated in tandem, one dry and the other with a controlled humidity environment, were used to measure f(RH) = bscat(RH)/bscat,dry, where bscat(RH) is the scattering coefficient measured at some relative humidity and bscat,dry is the scattering coefficient measured at RH <10%. The aerosol composition was highly variable in time, with a strong diurnal cycle. Organic carbon mass was observed to be, on the average, 70% of the fine mass with days where its contribution was well over 95% of the mass. Measurements of carbon isotopes revealed the fraction of carbon from biogenic sources to range from approximately 73 to 95%. Water soluble potassium was highly correlated with carbon mass, suggesting the influence of wood smoke. The ionic fraction of the aerosol consisted primarily of ammonium sulfate and in most cases nitrate was in the form of sodium nitrate. Fine soil mass was

  18. Estimates of aerosol species scattering characteristics as a function of relative humidity

    NASA Astrophysics Data System (ADS)

    Malm, William C.; Day, Derek E.

    The absorption of water by ambient aerosols can significantly increase the light scattering coefficient and thereby affect issues such as visibility and climate forcing. Although water absorption by inorganic compounds and mixtures of inorganic compounds can often be modeled with adequate certainty for most applications, modeling water uptake by organic aerosols at present is speculative. In this paper, we present data in the form of f (RH)=b scat(RH)/b scat,dry , where bscat(RH) is the scattering coefficient measured at some relative humidity (RH)>20% and bscat,dry is the scattering coefficient measured at RH <20%. The f(RH) has been measured at Great Smoky Mountains National Park in Tennessee and at Grand Canyon National Park in Arizona. The f(RH) curves obtained from these two sites, which show distinctly different aerosol composition and average RH values, are compared. We also present comparisons between the measured water uptake by ambient aerosol with modeled water uptake by inorganic compounds to estimate the water uptake by organic aerosol.

  19. Scattering and absorption characteristics of atmospheric aerosols over a semi-urban coastal environment

    NASA Astrophysics Data System (ADS)

    Aruna, K.; Lakshmi Kumar, T. V.; Rao, D. Narayana; Krishna Murthy, B. V.; Babu, S. Suresh; Krishnamoorthy, K.

    2014-11-01

    The scattering and absorption components of Aerosol Optical Depth (AOD) over a semi-urban coastal location (12.81°N, 80.03°E) near the mega city Chennai in peninsular India are separated using the collocated measurements of Black Carbon concentration and Atmospheric Boundary Layer Height (ABLH) from ERA Interim Reanalysis data assuming that most of the BC is contained and homogeneously mixed in the ABL. It is found that the absorption component to scattering component ratio has a strong seasonal variation with a pronounced maximum in the South West (SW) monsoon season. This is indicative of more effective wet removal of scattering aerosols than absorbing (BC) aerosols. There could also be an effect due to preferential removal of large particles which would have a lower content of BC. The Angstrom wavelength exponent shows a minimum in the SW monsoon season, the minimum being more pronounced for the scattering aerosols implying relative dominance of coarse mode particles. Investigation of the effect of Relative Humidity on scattering and absorption components of AOD revealed that the BC (absorbing) aerosols are non-hydrophilic/not coated with hydrophilic substance.

  20. Characteristics of atmospheric aerosols containing heavy metals measured on Fukue Island, Japan

    NASA Astrophysics Data System (ADS)

    Hidemori, Takehiro; Nakayama, Tomoki; Matsumi, Yutaka; Kinugawa, Takashi; Yabushita, Akihiro; Ohashi, Masafumi; Miyoshi, Takao; Irei, Satoshi; Takami, Akinori; Kaneyasu, Naoki; Yoshino, Ayako; Suzuki, Ryota; Yumoto, Yayoi; Hatakeyama, Shiro

    2014-11-01

    To investigate transport and chemical compositions of fine aerosols in the East Asian region, aerosol chemical components and their mixing states were measured at Fukue Island in the spring of 2010. Off-line chemical analyses using an ion chromatographic analyzer and an inductively coupled plasma-mass spectrometer for the aerosols sampled by a high volume sampler have also been conducted. The mixing state and temporal variation of number concentrations of the particles containing lead (Pb) and vanadium (V) were studied by using a laser ionization single-particle aerosol mass spectrometer (LISPA-MS). The temporal variation of number concentrations of particles containing Pb measured by the LISPA-MS is well consistent with those obtained by the chemical analysis of the aerosols sampled by the high volume sampler. The Pb-containing particles were classified into four types from the statistical analysis on the basis of the single-particle mass spectra with assists of laboratory experiments. It is estimated that 52% of observed particles containing Pb were originated from coal combustion. The concentration-weighted trajectory (CWT) analysis suggests that these particles are mainly transported from China continent. The V-containing particles were classified into three types. The 41% of V-containing particles were internally mixed with sea salt and the result of CWT analysis suggests that the potentially anthropogenic V-containing particles possibility emitted from ships are mixing with sea salt in the region that is highly loaded with sea salt in the Pacific Ocean.

  1. Chemical characteristics of organic aerosols in Algiers city area: influence of a fat manufacture plant

    NASA Astrophysics Data System (ADS)

    Yassaa, Noureddine; Meklati, Brahim Youcef; Cecinato, Angelo

    Total concentrations and homologue distributions of organic fraction constituents have been determined in particulate matter emitted from different units of a fat manufacturer (i.e. oils refining and conditioning plants, and production and conditioning units of a soap industry) located in Algiers area, as well as in atmospheric aerosols. In particular n-alkanes, n-alkanoic and n-alkenoic acids, n-alkan-2-ones and polycyclic aromatic hydrocarbons (PAH) were investigated. Organic aerosol contents varied broadly among the plant units, depending upon nature of the manufactured products. The percent composition of all classes of compounds investigated in ambient atmosphere was similar to those observed indoor at industrial plant units. Organic acids, n-alkanoic as well as n-alkenoic, appeared by far the most abundant organic constituents of aerosols, both indoor and outdoor, ranging from 7.7 to 19.8 and from 12.7 to 17.1 μg m -3, respectively. The huge occurrence of acids and n-alkanes in ambient aerosols was consistent with their high levels present in oil and fat materials. Among minor components of aerosols, n-alkan-2-ones and PAH, seemed to be related to thermally induced ageing and direct combustion of raw organic material used for oil and soap production.

  2. Aerosol physical and chemical properties retrieved from ground-based remote sensing measurements during heavy haze days in Beijing winter

    NASA Astrophysics Data System (ADS)

    Li, Z.; Gu, X.; Wang, L.; Li, D.; Xie, Y.; Li, K.; Dubovik, O.; Schuster, G.; Goloub, P.; Zhang, Y.; Li, L.; Ma, Y.; Xu, H.

    2013-10-01

    With the increase in economic development over the past thirty years, many large cities in eastern and southwestern China are experiencing increased haze events and atmospheric pollution, causing significant impacts on the regional environment and even climate. However, knowledge on the aerosol physical and chemical properties in heavy haze conditions is still insufficient. In this study, two winter heavy haze events in Beijing that occurred in 2011 and 2012 were selected and investigated by using the ground-based remote sensing measurements. We used a CIMEL CE318 sun-sky radiometer to retrieve haze aerosol optical, physical and chemical properties, including aerosol optical depth (AOD), size distribution, complex refractive indices and aerosol fractions identified as black carbon (BC), brown carbon (BrC), mineral dust (DU), ammonium sulfate-like (AS) components and aerosol water content (AW). The retrieval results from a total of five haze days showed that the aerosol loading and properties during the two winter haze events were comparable. Therefore, average heavy haze property parameters were drawn to present a research case for future studies. The average AOD is about 3.0 at 440 nm, and the Ångström exponent is 1.3 from 440 to 870 nm. The fine-mode AOD is 2.8 corresponding to a fine-mode fraction of 0.93. The coarse particles occupied a considerable volume fraction of the bimodal size distribution in winter haze events, with the mean particle radius of 0.21 and 2.9 μm for the fine and coarse modes respectively. The real part of the refractive indices exhibited a relatively flat spectral behavior with an average value of 1.48 from 440 to 1020 nm. The imaginary part showed spectral variation, with the value at 440 nm (about 0.013) higher than the other three wavelengths (about 0.008 at 675 nm). The aerosol composition retrieval results showed that volume fractions of BC, BrC, DU, AS and AW are 1, 2, 49, 15 and 33%, respectively, on average for the investigated

  3. Physical Properties and Chemical Composition of Aerosols sampled in T1 site during MILAGRO Campaign

    NASA Astrophysics Data System (ADS)

    Castro, T.; Mamani-Paco, R.; Saavedra, M. I.; Garcia, J.; Amador, O.; Carabali, G.; Salcido, A.; Herrera, E.; Baez, A.

    2007-05-01

    Results from pollutant measurements and meteorological variables corresponding to the month of March of 2006 during the MILAGRO campaign at site T1 are presented (Tecamac, State of Mexico). Three 8-stage cascade impactors (MOUDI) were employed to obtain aerosol samples of different sizes. For organic species analysis, samples were collected with a PM2.5 High Volume sampler. Mass and chemical composition (inorganic and organic species) were obtained with the use of analytical techniques. Particle morphology analysis was done with a TEM-EDAX System. Physical properties of aerosols were measured with a PSAP, a nephelometer and a CPC. According with area meteorology, days with Mexico City urban influence on T1 (March 9-12) and without influence (March 14 and 15) were analyzed. The particle average concentration during the whole campaign was 20,000 particles/cm3. For the days with and without urban influence the average concentrations were 17,500 and 8,000 particles/cm3 respectively. From the MOUDI data the highest particle concentration through the campaign was during the morning in the mode d50=0.32 μm. On the other hand, the cumulative highest concentration of all the stages was observed for March 19 followed by March 9. Scattering and absorption coefficients average obtained on T1 were 5.1x10-5 m-1 and 2.54x10-5 m-1 respectively and single scattering albedo was 0.676. These values show T1 as a polluted atmosphere, just as happens with megacities. Morphology of particles captured in a MOUDI impactor was studied. Particles between d50=0.18 μm and d50=1.8 μm sampled in T1 associated with urban influence (March 9) tended to show less irregular shapes through different periods of that day. These findings suggest the presence of large numbers of secondary aerosols and aged agglomerated particles. Particles ranging from d50=0.18 μm to d50=1.8 μm sampled in T1 and associated mainly with surrounding areas influence, e.g. Tizayuca Industrial Park (March 15) showed

  4. Physical and chemical characteristics of Lake Oahe, 1968-69

    USGS Publications Warehouse

    Selgeby, James H.; Jones, William E.

    1974-01-01

    The physical and chemical characteristics presented provide a description of Lake Oahe and establish bases for certain characteristics which may alter as the reservoir ages. Water temperatures were strongly influenced by wind-driven currents and water depth. The duration of thermal stratification varied from about 3 wk in the upstream portion of the reservoir to about 15 wk near the dam in 1968 and from unstratified upstream to about 15 wk downstream in 1969. Dissolved oxygen was usually near saturation, although it fell to 30% in 1968 and 43% in 1969. Nitrate nitrogen and soluble phosphorous were present on all sampling dates in 1969. Silica levels may have become limiting for diatoms in late summer, 1969.

  5. On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models

    DOE PAGESBeta

    Zhang, Shipeng; Wang, Minghuai; Ghan, Steven J.; Ding, Aijun; Wang, Hailong; Zhang, Kai; Neubauer, David; Lohmann, Ulrike; Ferrachat, Sylvaine; Takeamura, Toshihiko; et al

    2016-03-04

    Aerosol–cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (ω500), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascentmore » (ω500  <  −25 hPa day−1) and low clouds (stratocumulus and trade wind cumulus) where the models differ most. Shortwave aerosol indirect forcing is also found to differ significantly among different regimes. Shortwave aerosol indirect forcing in ascending regimes is close to that in subsidence regimes, which indicates that regimes with strong large-scale ascent are as important as stratocumulus regimes in studying AIE. It is further shown that shortwave aerosol indirect forcing over regions with high monthly large-scale surface precipitation rate (> 0.1 mm day−1) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes compared to the uncertainty in its global mean values, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.« less

  6. Aerosol characteristics and surface radiative forcing components during a dust outbreak in Gwangju, Republic of Korea.

    PubMed

    Ogunjobi, K O; Kim, Y J

    2008-02-01

    Atmospheric surface aerosol radiative forcing (SARF) DeltaF, forcing efficiency DeltaF(e) and fractional forcing efficiency DeltaFF(e) evaluated from cloud-screened narrowband spectral and thermal-offset-corrected radiometric observations during the Asia dust outbreak episodes in Gwangju, Republic of Korea are reported in this study. Columnar aerosol optical properties (aerosol optical depth (AOD), tau (alambda), Angstrom exponent alpha, mass concentration of fine and coarse mode particles) were also reported for the station between January 2000 and May 2001 consisting of 211cloud-free days. Results indicate that majority of the AOD were within the range 0.25-0.45 while some high aerosol events in which AODs > or = 0.6 were observed during the severe dust episodes. For example, AOD increases from annual average value of 0.34 +/- 0.13 at 501 nm to values >0.60 during the major dust events of March 27-30 and April 7-9, 2000, respectively. The alpha (501-870 nm) which is often used as a qualitative indicator of aerosol particle size had values ranging from 0.01 to 1.77. The diurnal forcing efficiency DeltaDF(e) at Gwangju was estimated to be -81.10 +/- 5.14 W m (-2)/tau (501 nm) and -47.09 +/- 2.20 W m (-2)/tau (501 nm) for the total solar broadband and visible band pass, respectively while the fractional diurnal forcing efficiency DeltaFDF(e) were -15.8 +/- 0.64%/tau (501 nm) and -22.87 +/- 1.13%/tau (501 nm) for the same band passes. Analyses of the 5-day air-mass back trajectories were further developed for Gwangju in order to classify the air-mass and types of aerosol reaching the site during the Asia dust episodes. PMID:17458510

  7. The Relationship of Freshmen's Physics Achievement and Their Related Affective Characteristics

    ERIC Educational Resources Information Center

    Gungor, Almer (Abak); Eryilmaz, Ali; Fakioglu, Turgut

    2007-01-01

    The purpose of this study was to determine the best-fitting structural equation model between the freshmen's physics achievement and selected affective characteristics related to physics. These characteristics are students' situational interest in physics, personal interest in physics, aspiring extra activities related to physics, importance of…

  8. Mixing states of aerosols over four environmentally distinct atmospheric regimes in Asia: coastal, urban, and industrial locations influenced by dust.

    PubMed

    Ramachandran, S; Srivastava, Rohit

    2016-06-01

    Mixing can influence the optical, physical, and chemical characteristics of aerosols, which in turn can modify their life cycle and radiative effects. Assumptions on the mixing state can lead to uncertain estimates of aerosol radiative effects. To examine the effect of mixing on the aerosol characteristics, and their influence on radiative effects, aerosol mixing states are determined over four environmentally distinct locations (Karachi, Gwangju, Osaka, and Singapore) in Asia, an aerosol hot spot region, using measured spectral aerosol optical properties and optical properties model. Aerosol optical depth (AOD), single scattering albedo (SSA), and asymmetry parameter (g) exhibit spectral, spatial, and temporal variations. Aerosol mixing states exhibit large spatial and temporal variations consistent with aerosol characteristics and aerosol type over each location. External mixing of aerosol species is unable to reproduce measured SSA over Asia, thus providing a strong evidence that aerosols exist in mixed state. Mineral dust (MD) (core)-Black carbon (BC) (shell) is one of the most preferred aerosol mixing states. Over locations influenced by biomass burning aerosols, BC (core)-water soluble (WS, shell) is a preferred mixing state, while dust gets coated by anthropogenic aerosols (BC, WS) over urban regions influenced by dust. MD (core)-sea salt (shell) mixing is found over Gwangju corroborating the observations. Aerosol radiative forcing exhibits large seasonal and spatial variations consistent with features seen in aerosol optical properties and mixing states. TOA forcing is less negative/positive for external mixing scenario because of lower SSA. Aerosol radiative forcing in Karachi is a factor of 2 higher when compared to Gwangju, Osaka, and Singapore. The influence of g on aerosol radiative forcing is insignificant. Results emphasize that rather than prescribing one single aerosol mixing state in global climate models regionally and temporally varying aerosol

  9. Characteristics of PM2.5 Carbonaceous Aerosol in Urban New York State

    NASA Astrophysics Data System (ADS)

    Khwaja, H. A.; Dutkiewicz, V.; Briggs, R.; Siddique, A.; Regan, J.

    2008-12-01

    In order to investigate the characteristics of carbonaceous fine aerosols, PM2.5 and size-segregated particulate samples (< 2.5 um, 2.5 - 4.2 um, 4.2 - 10 um, and 10 um) were collected during the summer in two urban sites of New York State viz., Botanical Garden (BTG), New York City and Empire State Plaza (ESP), Albany. Gas phase organic compounds were sampled with polyurethane foam (PUF) plugs. Particulate samples were acquired on quartz fiber filters using a high-volume air sampler (Hi-Vol) attached with a slotted impactor. Filters were sonicated in dichloromethane:methanol (9:1); extracts concentrated. A suite of more than 200 individual organic compounds was identified in the PM2.5 samples. Molecular markers, homologous compound series, and non-polar and polar organic compounds were detected at ng/m3 ambient concentrations using gas chromatography/mass spectrometry (GC/MS). Measurements of the organic carbon (OC) and elemental carbon (EC) were also made. Organic compounds detected in the size-segregated samples were grouped into different classes including phthalates and adipates, n-alkanes, alkanoic acids, cyclic siloxanes, waxes, benzoates, polyethylene glycols, squalene, and 4-nitro-butylated phenol. Results indicated that these organic species were predominantly associated in the fine particle mode (< 2.5 um). Gaseous organic compounds trapped in the PUF appeared rich in phenol, 4-nitro-2,6-ditertbutylphenol, pentachlorophenol, benzoic acid, alkanoic acids (C6 - C16 ), PAHs (naphthalene to pyrene), and phthalates. The major part of the extractable and elutable organic carbon was found to correspond to a complex mixture of phthalates and adipates, benzoate esters, n-alkanes, methyl silicates, phosphate esters, aldehydes and ketones, alcohols, alkyl amines, nitrosamines, formamides, amides, morpholines, carboxylic acids, methyl and isopropyl esters, dicarboxylic acids, waxes, lactones, hopanes, ionol 2, and PAHs. The most abundant classes of compounds are

  10. Characteristics of fine particle carbonaceous aerosol at two remote sites in Central Asia

    NASA Astrophysics Data System (ADS)

    Miller-Schulze, Justin P.; Shafer, Martin M.; Schauer, James J.; Solomon, Paul A.; Lantz, Jeffrey; Artamonova, Maria; Chen, Boris; Imashev, Sanjar; Sverdlik, Leonid; Carmichael, Greg R.; Deminter, Jeff T.

    2011-12-01

    Central Asia is a relatively understudied region of the world in terms of characterizing ambient particulate matter (PM) and quantifying source impacts of PM at receptor locations, although it is speculated to have an important role as a source region for long-range transport of PM to Eastern Asia, the Pacific Ocean, and the Western United States. PM is of significant interest not only because of its adverse effect on public health but also due to its more recently realized role in climate change. To investigate the sources and characteristics of PM in the region, a series of PM 2.5 and PM 10 samples were collected on an every-other-day basis at two sites (termed "Bishkek" and "Teploklyuchenka") in the Central Asian nation of the Kyrgyz Republic (also known as Kyrgyzstan) for a full year from July 2008 to July 2009. These samples were analyzed using standard methods for mass, organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-insoluble organic carbon by difference (OC minus WSOC) and a variety of molecular marker chemical species to be used in a chemical mass balance (CMB) model to apportion the sources of OC. These analyses indicate that approximately 19 ± 6.4% of the PM 2.5 mass at both sites throughout the year consists of OC. The carbonaceous component of PM 2.5 is dominated by OC, with OC/Total Carbon (TC) ratios being around 0.8 in the winter to almost 0.95 in the summer months. The CMB analysis indicated that mobile sources, i.e., gasoline and diesel engine exhaust, biomass combustion, and biogenic secondary organic aerosol (SOA) formation from isoprene and α-pinene precursors in the summer months were the dominant sources of OC. A strong positive correlation was observed between non-biomass burning WSOC and the un-apportioned OC from the CMB analysis, indicating that some of this un-apportioned OC is WSOC and likely the result of SOA-forming atmospheric processes that were not estimated by the CMB analysis performed. In

  11. Aerosol characteristics in north-east India using ARFINET spectral optical depth measurements

    NASA Astrophysics Data System (ADS)

    Pathak, B.; Subba, T.; Dahutia, P.; Bhuyan, P. K.; Moorthy, K. Krishna; Gogoi, M. M.; Babu, S. Suresh; Chutia, L.; Ajay, P.; Biswas, J.; Bharali, C.; Borgohain, A.; Dhar, P.; Guha, A.; De, B. K.; Banik, T.; Chakraborty, M.; Kundu, S. S.; Sudhakar, S.; Singh, S. B.

    2016-01-01

    Four years (2010-2014) of spectral aerosol optical depth (AOD) data from 4 Indian Space Research Organisation's ARFINET (Aerosol Radiative Forcing over India) stations (Shillong, Agartala, Imphal and Dibrugarh) in the North-Eastern Region (NER) of India (lying between 22-30°N and 89-98°E) are synthesized to evolve a regional aerosol representation, for the first time. Results show that the columnar AOD (an indicator of the column abundance of aerosols) is highest at Agartala (0.80 ± 0.24) in the west and lowest at Imphal (0.59 ± 0.23) in the east in the pre-monsoon season due to intense anthropogenic bio-mass burning in this region aided by long-range transport from the high aerosol laden regions of the Indo-Gangetic Plains (IGP), polluted Bangladesh and Bay of Bengal. In addition to local biogenic aerosols and pollutants emitted from brick kilns, oil/gas fields, household bio-fuel/fossil-fuel, vehicles, industries. Aerosol distribution and climatic impacts show a west to east gradient within the NER. For example, the climatological mean AODs are 0.67 ± 0.26, 0.52 ± 0.14, 0.40 ± 0.17 and 0.41 ± 0.23 respectively in Agartala, Shillong, Imphal and Dibrugarh which are geographically located from west to east within the NER. The average aerosol burden in NER ranks second highest with climatological mean AOD 0.49 ± 0.2 next to the Indo-Gangetic Plains where the climatological mean AOD is 0.64 ± 0.2 followed by the South and South-East Asia region. Elevated aerosol layers are observed over the eastern most stations Dibrugarh and Imphal, while at the western stations the concentrations are high near the surface. The climate implications of aerosols are evaluated in terms of aerosol radiative forcing (ARF) and consequent heating of the atmosphere in the region which follows AOD and exhibit high values in pre-monsoon season at all the locations except in Agartala. The highest ARF in the atmosphere occurs in the pre-monsoon season ranging from 48.6 Wm-2 in Agartala

  12. Analysis of the chemical and physical properties of combustion aerosols: State of the art.

    EPA Science Inventory

    The impact of combustion aerosols on human health is well documented byepidemiological studies, however the effect of low concentrations of ultrafineparticles on the human lung are not yet fully understood. With the advent ofnovel measurement technologies for simultaneous charact...

  13. Aerosol characteristics in Phimai, Thailand determined by continuous observation with a polarization sensitive Mie-Raman lidar and a sky radiometer

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Shimizu, Atsushi; Nishizawa, Tomoaki; Matsui, Ichiro; Jin, Yoshitaka; Khatri, Pradeep; Irie, Hitoshi; Takamura, Tamio; Aoki, Kazuma; Thana, Boossarasiri

    2015-06-01

    Distributions and optical characteristics of aerosols were continuously observed with a polarization-sensitive (532 nm), Mie-scattering (532 and 1064 nm) and Raman-scattering (607 nm) lidar and a sky radiometer in Phimai, Thailand. Polarization lidar measurements indicated that high concentration plumes of spherical aerosols considered as biomass burning smoke were often observed in the dry season. Plumes of non-spherical aerosols considered as long-range transported soil dust from Africa, the Middle East, or Northeast Asia were occasionally observed. Furthermore, low-concentration non-spherical aerosols were almost always observed in the atmospheric mixing layer. Extinction coefficient profiles of spherical aerosols and non-spherical dust exhibited different diurnal variations, and spherical aerosols including smoke were distributed in higher altitudes in the mixing layer and residual layer. The difference can be explained by hygroscopic growth of smoke particles and buoyancy of the smoke. Analysis of seasonal variations of optical properties derived from the Raman lidar and the sky radiometer confirmed that the lidar ratio, aerosol optical depth, and Angstrom exponent were higher in the dry season (October-May) and lower in the wet season (June-September). The single scattering albedo was lower in the dry season. These seasonal variations are explained by frequent biomass burning in the dry season consistent with previous studies in Southeast Asian region. At the same time, the present work confirmed that soil dust was a major aerosol component in Phimai, Thailand.

  14. Application of both a physical theory and statistical procedure in the analyses of an in vivo study of aerosol deposition

    SciTech Connect

    Cheng, K.H.; Swift, D.L.; Yang, Y.H.

    1995-12-01

    Regional deposition of inhaled aerosols in the respiratory tract is a significant factor in assessing the biological effects from exposure to a variety of environmental particles. Understanding the deposition efficiency of inhaled aerosol particles in the nasal and oral airways can help evaluate doses to the extrathoracic region as well as to the lung. Dose extrapolation from laboratory animals to humans has been questioned due to significant physiological and anatomical variations. Although human studies are considered ideal for obtaining in vivo toxicity information important in risk assessment, the number of subjects in the study is often small compared to epidemiological and animal studies. This study measured in vivo the nasal airway dimensions and the extrathoracic deposition of ultrafine aerosols in 10 normal adult males. Variability among individuals was significant. The nasal geometry of each individual was characterized at a resolution of 3 mm using magnetic resonance imaging (MRI) and acoustic rhinometry (AR). The turbulent diffusion theory was used to describe the nonlinear nature of extrathoracic aerosol deposition. To determine what dimensional features of the nasal airway were responsible for the marked differences in particle deposition, the MIXed-effects NonLINear Regression (MIXNLIN) procedure was used to account for the random effort of repeated measurements on the same subject. Using both turbulent diffusion theory and MIXNLIN, the ultrafine particle deposition is correlated with nasal dimensions measured by the surface area, minimum cross-sectional area, and complexity of the airway shape. The combination of MRI and AR is useful for characterizing both detailed nasal dimensions and temporal changes in nasal patency. We conclude that a suitable statistical procedure incorporated with existing physical theories must be used in data analyses for experimental studies of aerosol deposition that involve a relatively small number of human subjects.

  15. Chemical and Physical Properties of Bulk Aerosols Observed During TRACE-P: Evidence of Nitrate Uptake on Dust Particles

    NASA Astrophysics Data System (ADS)

    Jordan, C.; Anderson, B.; Hudgins, C.; Winstead, E.; Thornhill, L.; Talbot, R.; Russo, R.; Scheuer, E.; Seid, G.; Dibb, J.; Fuelberg, H.

    2002-12-01

    Back trajectories and bulk aerosol chemical properties have been used to group aerosol samples measured on the DC-8 during TRACE-P into five source regions. Each of these source region groups was further subdivided into three altitude bins (< 2 km, 2 - 7 km, and > 7 km). The mean chemical signatures, size distributions, and other physical properties (e.g., volatility, single scatter albedo) will be presented for these groups. By combining chemical and physical measurements, the observed aerosol population for each group may be partitioned between black carbon, sea salts, non-sea salt water soluble ions, and dust. Using this approach, we have found that the bulk of the dust emanating from Asia during TRACE-P came from one region. The highest concentrations of pollution species were also found in this region, including particulate nitrate. The presence of gas phase pollutants such as nitric acid co-located with the dust allows for the uptake of gas-phase nitrogen onto the dust surfaces. Results show that in the dust sector at mid-altitudes (2 - 7 km), where the influence of sea salt is reduced compared to lower altitudes, 50% of the total nitrate is in particulate form. This is in contrast to 15% for sectors with little dust.

  16. Characteristics of aerosol at a lower atmospheric layer in DRAGON field campaign

    NASA Astrophysics Data System (ADS)

    KUJI, M.; Azuma, Y.; Kitakoga, S.; Sano, I.; Holben, B. N.

    2013-12-01

    Air pollution arises severely over East Asia with the rapid economic development nowadays. Monitoring the atmospheric environment, as one of the purposes, an intensive field campaign, Distributed Regional Aerosol Gridded Observation Networks (DRAGON), was carried out in the spring of year 2012, led by National Aeronautics and Space Administration (NASA). At that time, atmospheric phenomena such as Yellow sand and haze events were observed at Nara in the western part of Japan, as one of the DRAGON observation sites. The atmospheric events were characterized with the AErosol RObotic NETwork (AERONET) data. As a result of the data analysis, it was found that more light-absorbing and smaller particles dominated at the lower than upper atmospheric layer for the Kosa event in particular. A backward trajectory analysis suggested that the Yellow sand event traveled over the East Asian industrial cities, which could lead to a mixture of sand and air pollutants with moderate particle size and light-absorptivity. In addition, visibility observation was evaluated quantitatively with AERONET data in the DRAGON campaign since eye observation was inherently semi-quantitative. The extinction coefficient estimated from visibility was compared to that from AERONET. As a result, it was found that the extinction coefficients were generally consistent to each other. But there were some discrepancies, which could be caused with the atmospheric phenomena or aerosol types. It is confirmed that visibility is strongly influenced with aerosols in the case of severe atmospheric phenomena in particular.

  17. Composition and Characteristics of Aerosols in the Southern High Plains of Texas (USA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerosol samples on polycarbonate filters were collected daily for several years in the Southern High Plains region of western Texas. Selected samples representing a variety of size modes, locations, and air quality conditions were analyzed by PIXE. Silicon and other crustal elements dominated duri...

  18. Comparison of characteristics of aerosol during rainy weather and cold air-dust weather in Guangzhou in late March 2012

    NASA Astrophysics Data System (ADS)

    Chen, Huizhong; Wu, Dui; Yu, Jianzhen

    2016-04-01

    Using the data on aerosol observed hourly by Marga ADI 2080 and Grimm 180, we compared the characteristics of aerosol during rainy weather and cold air-dust weather in Guangzhou in late March 2012. The mass concentration of aerosol appeared distinct between the two weather processes. During rainy weather, the mass concentration of PM and total water-soluble components decreased obviously. During cold air-dust weather, the cleaning effect of cold air occurred much more suddenly and about a half day earlier than the dust effect. As a result, the mass concentration of PM and total water-soluble components first dropped dramatically to a below-normal level and then rose gradually to an above-normal level. The ratio of PM2.5/PM10 and PM1/PM10 decreased, suggesting that dust-storm weather mainly brought in coarse particles. The proportion of Ca2+ in the total water-soluble components significantly increased to as high as 50 % because of the effect of dust weather. We further analysed the ionic equilibrium during rainy and cold air-dust weather, and compared it with that during hazy weather during the same period. The aerosol during rainy weather was slightly acidic, whereas that during hazy weather and cold air-dust weather was obviously alkaline, with that during cold air-dust weather being significantly more alkaline. Most of the anions, including SO4 2- and NO3 -, were neutralised by NH4 + during rainy and hazy weather, and by Ca2+ during cold air-dust weather.

  19. Sensitivity of aerosol optical depth, single scattering albedo, and phase function calculations to assumptions on physical and chemical properties of aerosol

    EPA Science Inventory

    In coupled chemistry-meteorology simulations, the calculation of aerosol optical properties is an important task for the inclusion of the aerosol effects on the atmospheric radiative budget. However, the calculation of these properties from an aerosol profile is not uniquely defi...

  20. Impact of aerosol composition and foliage characteristics on forest canopy deposition rates: A laboratory study

    NASA Astrophysics Data System (ADS)

    Hornsby, K. E.; Pryor, S. C.

    2013-12-01

    Forests are a major sink for atmospheric aerosols. Hence it has been suggested that (i) increased tree planting in urban areas might lead to a reduction in aerosol particle concentrations and thus a reduction in respiratory conditions and heart complications, and (ii) forests may be responsible for removing a disproportionately large fraction of potentially climate-relevant fine and ultra-fine aerosol particles from the atmosphere. However, larger uncertainties remain with respect to controls on uptake rates for forests. E.g. the deposition flux partitioning between foliage and non-foliage elements, the influence of particle size and composition, the role of leaf surface morphology and stomatal aperture in surface uptake. Improved understanding of the relative importance of these factors and the variability across different tree species should help determine how much of a sink naturally occurring and planted forests can provide downstream of fine particle production. In this study, a sample of trees native to southern Indiana were exposed to ultra-fine aerosol particle populations in a 1.5 m x 1.5 m x 1.5 m Teflon chamber. Stable particle size distributions (PSD) with geometric mean diameters (GMD) ranging from 40 to 80 nm were generated from sodium chloride, ammonium nitrate, ammonium sulfate and sodium sulfite solutions using a TSI model 3940 Aerosol Generation System (AGS). The aerosol stream was diluted using scrubbed and dried zero air to allow a variation of total number concentration across two orders of magnitude. PSD in the chamber are continuously measured using a TSI Scanning Mobility Particle Spectrometer (SMPS) comprising an Electrostatic Classifier (EC model 3080) attached to a Long DMA (LDMA model 3081) and a TSI model 3025A Butanol Condensation Particle Counter (CPC) operated with both the internal diffusion loss and multiple charge corrections turned on. The composition of the chamber air was also monitored for carbon dioxide (CO2) and water vapor

  1. Physical and chemical characteristics of pitaya fruits at physiological maturity.

    PubMed

    Ortiz, T A; Takahashi, L S A

    2015-01-01

    The aim of this study was to analyze the physical and chemical characteristics of the maturation process of pitaya fruit (Hylocereus undatus) to identify indicators that can be used to determine the point of physiological maturity and establish the optimal timing of physiological maturity for harvesting the fruit. A completely randomized experimental design was employed and four biological repeats were performed. Physiological maturity was assessed using various physical characteristics: longitudinal length (LL), equatorial diameter (ED), pericarp thickness (PeT), pulp thickness (PuT), fruit mass (FM), pulp mass (PuM), pericarp mass (PeM), pericarp percentage (%Pe), pulp percentage (%Pu), pulp/pericarp ratio (Pu/Pe), pericarp color index (CI), hue color angle (h°), lightness index (L*), chroma (C*), blue-yellow variation (b*), and green-red variation (a*). Additionally, chemical characteristics such as soluble solid content (SS), titratable acidity (TA), SS/TA ratio, and pH were screened. The data were statistically analyzed by fitting regression models and computing Pearson's correlation coefficients (P < 0.05). Physiological maturity in pitaya fruits occurred between the 30th and 32nd days after anthesis, and this proved to be the optimal period for harvest. At this time, the fruit was completely red with high SS, and had the recommended values of TA, pH, and SS/TA ratio. During this period, ED, PuT, FM, PuM, %Pu, and Pu/Pe increased while PeT, PeM, and %Pe fell; these changes are considered desirable by producers and/or consumers. PuM was the variable that displayed more strong's association with other variables in the analysis. PMID:26600501

  2. Characteristics of aerosols in east Asian outflow at Cheju in spring

    NASA Astrophysics Data System (ADS)

    Sahu, L. K.; Kondo, Y.; Miyazaki, Y.; Koike, M.; Takegawa, N.; Tanimoto, H.; Matsueda, H.

    2007-12-01

    Measurements of aerosols and traces gases were conducted at Gosan site (33o17'N, 126o10'E) on Cheju Island, South Korea from 17 March to 6 April 2005. In the spring season, outflows of pollutants from east Asian continents are associated with high pressure system centered over northern region of China and Mongolia. Measurements were continuous for carbonaceous aerosols (BC, OC and WSOC), PM2.5 inorganic aerosols, and trace gases. To investigate dominate source region and transport pathway of air parcels 5-day isentropic back trajectories at 950 hPa were calculated. Based on these trajectories air masses were classified in five contrastingly different categories as (1) Maritime (11%), (2) Free tropospheric (34%), (3) Yellow Sea (16%), (4) Korean (8%), and (5) Chinese (31%). Temporal variations of aerosols and trace gases track each other, in particular for species primarily emitted by anthropogenic activities. All species were observed to show large variability due to alteration in the episodes of air masses from different categories. Mean (× SD) mass concentrations of BC, OC, WSOC and SO42- were 1.18×0.83, 4.2×1.6, 1.26×1.01 and 4.0×3.4' m-3, respectively. Concentrations of carbonaceous and PM2.5 aerosols, which are emitted by anthropogenic activities, show lowest in maritime and highest in Chinese plume. The mean concentrations of BC, OC, WSOC and SO42- in Chinese plume were 1.9×0.92, 5.5×1.3, 2.0×1.1 and 6.7×4.1' m-3, respectively. The observed slope E×BC/E×CO =9.2 (n' m-3/ppbv) will be compared with emission inventory data over China. K+ shows good correlations with SO42- and NO3- signifying role of combustion related process like biomass burning.

  3. Chemical characteristics of ambient aerosols contributed by cooking process at Noorpur village near New Delhi

    NASA Astrophysics Data System (ADS)

    Singh, Sudha

    Generally, industrial and transport sectors are considered as major contributors of air pollution but recently, biomass burning is also reported as a major source of atmospheric aerosols (1, 2) especially in the developing world where solid fuels such as dung cake, wood and crop residues are used in traditional cooking which are responsible for poor air quality, respiratory problems and radiative forcing etc .In India, most of the research has been focused on emission estimates from biomass burning and cooking. No effort has been made to understand the chemistry and sources of fine aerosols in rural areas during cooking hours. This study fills this knowledge gap and strengthens our understanding about abundance of various chemical constituents of atmospheric aerosols emitted during cooking hours.Aerosol samples were collected from village called Noorpur (28.470 N, 77.030 E) which lies near Delhi city. Sampling was carried out during August 2011-May 2012 by using handy sampler (Envirotech model APM 821) installed at the terrace of a building (~6m). The aerosol samples were collected on 8 hourly basis at a flow rate of 1 LPM. Water extracts of these filters were analyzed for major anions (F-, Cl-, NO3-, SO42-) and major cations (Na+, NH4+, K+, Ca2+ Mg2+) by ion chromatography (Metrohm 883 Basic IC Plus). During cooking period, the concentration of the major ions followed the order of Ca2+> SO42-> NO3-> Cl-> K+> NH4+> Mg2+> Na2+> F-. Among anion SO42 (5 µg/m3) showed highest value and in case of cations Ca2+ (7.32µg/m3) has highest value.

  4. Physical Characteristics of Triggered Lightning Determined by Optical Spectroscopy

    NASA Astrophysics Data System (ADS)

    Walker, T. D.; Hill, J. D.; Jordan, D. M.; Uman, M. A.; Christian, H.

    2010-12-01

    In the summers of 2009 and 2010, optical spectra of 37 triggered return strokes have been recorded at the International Center for Lightning Research and Testing in north-central Florida. The spectrometer that was used has an average dispersion of 260 Angstroms/mm resulting in an average resolution of 5 Angstroms/pixel when mated to a Photron (SA1.1) high-speed camera. The spectra captured with this system had a free spectral range of 3800-8000 Angstroms and were captured at 300,000 frames per second. The spectrometer's vertical field of view was approximately 2.6 m at an altitude 85 m above the launch tower, intended to view the middle of the triggering wire, and 3 m at 300 m above the launch tower, intended to view the natural portion of the triggered lightning channel. Physical properties of the lightning channel, including temperature, electron number density, and optical luminosity, are coordinated with current measurements at the base of the triggered lightning channel. These physical properties were all found to correlate with changes in the current. Temperature measurements throughout the strokes varied from 8000-34000 K, and electron number densities ranged from 0.2-1.0 x 10^18 cm^-3. The physical characteristics of the copper and natural portions of the triggered lightning channel are compared.

  5. AEROSOL AND GAS MEASUREMENT

    EPA Science Inventory

    Measurements provide fundamental information for evaluating and managing the impact of aerosols on air quality. Specific measurements of aerosol concentration and their physical and chemical properties are required by different users to meet different user-community needs. Befo...

  6. Ambient measurements of chemical and physical properties of organic aerosols: Insights into formation, growth, and heterogeneous chemistry

    NASA Astrophysics Data System (ADS)

    Ziemba, Luke D.

    Organic aerosols are a ubiquitous component of the troposphere, from heavily polluted cities to the remote Arctic. In Chapters II, III, and V of this dissertation, the formation of organic aerosol through observations of ambient size distributions is addressed. Chapter IV presents a new pathway for the formation of nitrous acid (HONO) in the urban atmosphere. In Chapter II, the size-resolved chemical composition of sub-micron aerosol was measured at a suburban forested site in North Carolina. Two events were identified in which particle growth, presumably by gas-to-particle conversion, was dominated by accumulation of organic aerosol mass. Growth rates between 1.2 nm hr-1 and 4.9 nm hr-1 were observed. Using a mass-spectral deconvolution method coupled with linear regression analysis, the sub-micron organic aerosol mass observed during the campaign, and during events, was determined to have been influenced by both local and regional secondary processes with only a minor influence from combustion sources. In Chapter III, the chemical characteristics of sub-10-micron aerosol were explored as a function of ambient particle size at a coastal and inland site in New England. Average organic carbon (OC) concentrations of 4.9 microg C m-3 and 3.4 microg C m-3 were observed at the coastal site at the Isles of Shoals (IOS) and at the slightly inland site at Thompson Farm (TF), respectively. An average of 84 and 72% of OC was found to be water-soluble at IOS and TF, respectively. Size distributions indicate that the formation of dicarboxylic acids, especially oxalic acid, is driven by aqueous-phase reactions. A chemical fingerprint analysis suggests that all water-soluble OC at IOS resembles secondary organic aerosol (SOA), while WSOC at TF appears to result from mixed sources. In Chapter IV, a newly identified formation pathway for nitrous acid (HONO) is presented. HONO is an important precursor to hydroxyl radicals in the troposphere and thus contributes to the oxidative

  7. Carbonaceous aerosol over semi-arid region of western India: Heterogeneity in sources and characteristics

    NASA Astrophysics Data System (ADS)

    Sudheer, A. K.; Aslam, M. Y.; Upadhyay, M.; Rengarajan, R.; Bhushan, R.; Rathore, J. S.; Singh, S. K.; Kumar, S.

    2016-09-01

    Carbonaceous species (elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC)) and water-soluble inorganic species (Na+, NH4+, K+, Ca2 +, Mg2 +, Cl-, NO3-, SO42 -) in PM10 and PM2.5 from Ahmedabad and Jodhpur (urban and semi-urban locations, respectively) in western India were measured during May-September, 2011. Stable isotope composition of carbonaceous aerosol (δ13C of TC) in PM10 samples was also determined. Average EC concentration in PM10 at Ahmedabad was 1 μg m- 3 (range: 0.34 to 3.4 μg m- 3), almost 80% of which remained in PM2.5. Similarly, 70% of EC in PM10 (average: 0.9 μg m- 3) resided in PM2.5 at Jodhpur. Average OC concentration at Ahmedabad was 6.4 μg m- 3 and ~ 52% of this was found in PM2.5. On the contrary, OC concentration at Jodhpur was 40 μg m- 3, 80% of which was found in coarse particles contributing substantially to aerosol mass. δ13C of TC (average: - 27.5‰, range: - 29.6 to - 25.8‰) along with WSOC/EC ratio shows an increasing trend at Jodhpur suggesting the possibility of aging of aerosol, since aging results in enrichment of heavier isotope. OC and WSOC show significant correlations with K+ and not with EC, indicating biogenic origin of OC. Different size distributions are also exhibited by WSOC at the two stations. On the other hand, δ13C exhibits an inverse trend with sea-salt constituents at Ahmedabad, indicating the influence of air masses transported from the western/south-western region on carbonaceous aerosol. These results suggest that a strong heterogeneity exists in the sources of carbonaceous aerosol over this region and potential sources of non-combustion emissions such as bio-aerosol that need further investigation.

  8. Titan's Aerosol and Stratospheric Ice Opacities Between 18 and 500 Micrometers: Vertical and Spectral Characteristics from Cassini CIRS

    NASA Technical Reports Server (NTRS)

    Anderson, Carrie M.; Samuelson, Robert E.

    2011-01-01

    Vertical distributions and spectral characteristics of Titan's photochemical aerosol and stratospheric ices are determined between 20 and 560 per centimeter (500-18 micrometers) from the Cassini Composite Infrared Spectrometer (CIRS). Results are obtained for latitudes of 15 N, 15 S, and 58 S, where accurate temperature profiles can be independently determined. In addition, estimates of aerosol and ice abundances at 62 N relative to those at 15 S are derived. Aerosol abundances are comparable at the two latitudes, but stratospheric ices are approximately 3 times more abundant at 62 N than at 15 S. Generally, nitrile ice clouds (probably HCN and HC3N), as inferred from a composite emission feature at approximately 160 per centimeter, appear to be located over a narrow altitude range in the stratosphere centered at approximately 90 km. Although most abundant at high northern latitudes, these nitrile ice clouds extend down through low latitudes and into mid southern latitudes, at least as far as 58 S. There is some evidence of a second ice cloud layer at approximately 60 km altitude at 58 S associated with an emission feature at approximately 80 per centimeter. We speculate that the identify of this cloud may be due to C2H6 ice, which in the vapor phase is the most abundant hydrocarbon (next to CH4) in the stratosphere of Titan. Unlike the highly restricted range of altitudes (50-100 km) associated with organic condensate clouds, Titan's photochemical aerosol appears to be well-mixed from the surface to the top of the stratosphere near an altitude of 300 km, and the spectral shape does not appear to change between 15 N and 58 S latitude. The ratio of aerosol-to-gas scale heights range from 1.3-2.4 at about 160 km to 1.1-1.4 at 300 km, although there is considerable variability with latitude, The aerosol exhibits a very broad emission feature peaking at approximately 140 per centimeter. Due to its extreme breadth and low wavenumber, we speculate that this feature may

  9. Aerosol deposition characteristics in distal acinar airways under cyclic breathing conditions

    PubMed Central

    Ma, Baoshun

    2011-01-01

    Although the major mechanisms of aerosol deposition in the lung are known, detailed quantitative data in anatomically realistic models are still lacking, especially in the acinar airways. In this study, an algorithm was developed to build multigenerational three-dimensional models of alveolated airways with arbitrary bifurcation angles and spherical alveolar shape. Using computational fluid dynamics, the deposition of 1- and 3-μm aerosol particles was predicted in models of human alveolar sac and terminal acinar bifurcation under rhythmic wall motion for two breathing conditions (functional residual capacity = 3 liter, tidal volume = 0.5 and 0.9 liter, breathing period = 4 s). Particles entering the model during one inspiration period were tracked for multiple breathing cycles until all particles deposited or escaped from the model. Flow recirculation inside alveoli occurred only during transition between inspiration and expiration and accounted for no more than 1% of the whole cycle. Weak flow irreversibility and convective transport were observed in both models. The average deposition efficiency was similar for both breathing conditions and for both models. Under normal gravity, total deposition was ∼33 and 75%, of which ∼67 and 96% occurred during the first cycle, for 1- and 3-μm particles, respectively. Under zero gravity, total deposition was ∼2–5% for both particle sizes. These results support previous findings that gravitational sedimentation is the dominant deposition mechanism for micrometer-sized aerosols in acinar airways. The results also showed that moving walls and multiple breathing cycles are needed for accurate estimation of aerosol deposition in acinar airways. PMID:21330617

  10. The detection of clouds, aerosols and marine atmospheric boundary layer characteristics from simulated GLAS data

    NASA Technical Reports Server (NTRS)

    Palm, Stephen P.; Spinhirne, James D.

    1998-01-01

    Scheduled for launch in 2001 as part of NASA's Earth Observing System (EOS), the Geoscience Laser Altimeter System (GLAS) will provide continuous laser sounding of the earth's atmosphere from space for the first time. From its polar orbit about 600 km above the surface, GLAS will employ a 40 Hz solid state laser operating at 1064 nm to measure topography to an accuracy of 10 cm. Simultaneously, the atmospheric channels (1064 and 532 nm) of GLAS will provide profiles of atmospheric backscatter from 40 km to the ground with 75 meter vertical resolution (Spinhirne and Palm, 1996). These measurements will give scientists an unprecedented global data set on the vertical structure of clouds and aerosols which will greatly aid research efforts aimed at understanding their effects on climate and their role in climate change (Hartman, 1994). To better understand and predict the performance of the GLAS atmospheric channels, a computer model was developed to simulate the type of signal that the instrument would likely produce. The model uses aircraft lidar data and provides realistic simulated GLAS data sets over large areas spanning a wide range of atmospheric conditions. These simulated GLAS datasets are invaluable for designing and testing algorithms for the retrieval of parameters such as cloud and aerosol layer height, optical depth and extinction cross section. This work is currently proceeding and in this paper we will present results of the cloud and aerosol detection algorithm with emphasis on the detection of Marine Atmospheric Boundary Layer (MABL) aerosol. In addition, we use a recently developed technique to ascertain the feasability of estimating MABL moisture and temperature structure from spaceborne systems such as GLAS.

  11. Carbonaceous aerosol characteristics over Delhi in Northern India: Seasonal variability and possible sources

    NASA Astrophysics Data System (ADS)

    Srivastava, Atul Kumar; Bisht, Ds; Tiwari, S.

    Carbonaceous aerosols have been the focus of extensive studies during the last decade due to its significant impacts on human health, visibility and climate change. As per Asian regions are concerned, aerosols in south-Asia are gaining considerable importance because of their potential impacts on regional climate, yet their possible sources are poorly understood. Semi-continuous measurements of organic carbon (OC) and elemental carbon (EC) and continuous measurements of black carbon (BC) aerosols were conducted simultaneously at Delhi during the period from January 2011 to May 2012. Delhi is the capital city of India and one of the densely populated and industrialized urban megacities in Asia, located at the Ganga basin in the northern part of India. Being highly polluted region, mass concentrations of OC, EC and BC over Delhi were found to vary from about 6-92 mug m (-3) (mean: 23±16 mug m (-3) ), 3-38 mug m (-3) (mean: 11±7 mug m (-3) ) and 1-24 mug m (-3) (mean: 7±5 mug m (-3) ), respectively during the entire measurement period, with about two times higher concentration during winter as compared to summer. A significant correlation between OC and EC (R=0.95, n=232) and relatively lower OC/EC ratio (range: 1.0-3.6; mean: 2.2±0.5) suggest fossil fuel emission as a dominant source of carbonaceous aerosols over the station. The average mass concentration of EC was found about 38% higher than BC during the study period, which is interestingly different as reported at other locations over Ganga basin. We also determined the associated optical properties of carbonaceous species (e.g. absorption coefficient and mass absorption efficiency) over the station. Significant loading of carbonaceous species over such regions emphasize an urgent need to focus on air quality management and proper impact assessment on health perspective.

  12. Orbital and Physical Characteristics of Meter-sized Earth Impactors

    NASA Astrophysics Data System (ADS)

    Brown, Peter G.; Wiegert, Paul; Clark, David; Tagliaferri, Edward

    2015-11-01

    We have analysed the orbits and ablation characteristics in the atmosphere of more than 60 earth-impacting meteoroids of one meter in diameter or larger. Using heights at peak luminosity as a proxy for strength, we find that there is roughly an order of magnitude spread in the apparent strength of the population of meter-sized impactors at the Earth. The orbits and physical strength of these objects are consistent with the majority being asteroidal bodies originating from the inner main asteroid belt. We find ~10-15% of our objects have a probable cometary (Jupiter-Family comet and/or Halley-type comet) origin based on orbital characteristics alone. Only half this number, however, show evidence for the expected weaker than average structure compared to asteroidal bodies. Almost all impactors show peak brightness between 20-40 km altitude. Several events have exceptionally high (relative to the remainder of the population) heights of peak brightness. These are physically most consistent with high microporosity objects, though all were on asteroidal-type orbits. We also find three events, including the Oct 8, 2009 airburst near Sulawesi, Indonesia, which display comparatively low heights of peak brightness, consistent with strong monolithic stones or iron meteoroids. Based on orbital similarity, we find a probable connection among several NEOs in our population with the Taurid meteoroid complex. No other major meteoroid streams show linkages with the pre-atmospheric orbits of our meter-class impactors. Our events cover almost four orders of magnitude in mass, but no trend in height of peak brightness is evident, suggesting no strong trend in strength with size for small NEOs, a finding consistent with the results of Popova et al (2011).

  13. Aerosol Chemical and Physical Properties Observed over Puerto Rico in the Tropical North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Jusino-Atresino, R.; Xia, L.; Song, F.; Gao, Y.

    2008-12-01

    Tropospheric aerosols that originate in Africa and are transported over the Atlantic Ocean have potential impacts over the Caribbean region. To investigate aerosol properties over this region, air sampling was conducted at San Juan Cape (18.46°N, 66.12°W), Puerto Rico during the summer months in 2006. Aerosol samples were collected by both commercial PM2.5 sampler and in-house fabricated TSP sampler. Analyses of aerosols were made through the use of the following instrumental methods: (1)Ion Chromatography for the determinations of water-soluble cations (sodium, ammonium, potassium, magnesium and calcium) and anions (fluoride, acetate, propionate, methanesulfonate, chloride, nitrate, succinate, malonate, sulfate and oxalate); (2)Inductively Coupled Plasma Mass Spectrometry for the concentrations of selected trace elements (Al, Fe, Mn, Sc, Cd, Pb, Sb, Ni, Co, Cr, Cu, Zn and V); (3)Scanning Electron Microscopy for individual aerosol particle characterization. Crustal enrichment factors were calculated to determine the strength of crustal source. Preliminary results indicate that sodium (22 - 99 μg m- 3) and ammonium (1.1 - 50 μg m-3) were the major cations and chloride (1.5 - 99 μg m-3) and sulfate (35 μg m-3) were the dominant anions. Malonate (3.8 - 6.9 μg m- 3) was the most abundant organic anion. Atmospheric concentrations of iron ranged 0.30 - 3.3 ng m- 3. The elements, Sc, Cd, Pb, Sb, Ni, Co, Cr, Cu, Zn and V, were enriched by factors of 600 to 40,000 relative to their natural abundance in crustal soil. Principal components analysis indicates six assemblages of fifteen types of aerosol particles, dominated by Si - rich particles.

  14. Sheep milk: physical-chemical characteristics and microbiological quality.

    PubMed

    Merlin Junior, Ivandré Antonio; Santos, Joice Sifuentes dos; Costa, Ligia Grecco; Costa, Renan Grecco; Ludovico, Agostinho; Rego, Fabiola Cristine de Almeida; Santana, Elsa Helena Walter de

    2015-09-01

    Sheep milk is the third most consumed milk in Brazil. It is much appreciated for its nutritional status and is important for children that have problems with cow milk. Little information is known about the chemical, physical and microbiological composition of sheep milk from South Brazil. Thus, the aim of this study was to describe chemical and microbiological characteristics of sheep milk produced on two rural properties located in southern Brazil (ParanA and Rio Grande do Sul). The chemical composition of sheep milk was 17.32 g/100 g total solids, 5.86 g/100 g total protein, 4.46 g/100 g casein, 1.08 g/100 g whey protein, 7.28 g/100 g fat, 0.93 g/100 g ash, and 3.41 g/100 g lactose. High somatic cell count (1.7x106 cells/mL), total mesophilic bacterias (16.0 x 106 CFU/mL) and psychrotrophics (5.8 x 106 CFU/mL) were observed. Growth of Staphylococcus aureus, enterobacteria and coliforms occurred in 100% of the samples, and 45% of the samples showed growth of Escherichia coli. The sheep milk physical-chemical and microbiology parameters are similar to those presented in the literature for other countries but somatic cell count presented high levels. PMID:26821492

  15. Physical characteristics of geosynchronous high power communications satellites

    SciTech Connect

    Drackett, T.M.

    1995-12-31

    With the advent of the Information Superhighway, many organizations have been spurred into re-examining current spacecraft architectures to determine how the significantly higher communications capacities of the future will be accommodated. Opinion is divided on many issues in this arena, and none more so than the discussion that revolves around whether several large satellites in Geosynchronous Orbit (GEO) offer a better all-round service to the user community than a fleet of small satellites in Low Earth Orbit (LEO). Although this paper does not attempt to debate this particular issue, a clear finding of the work carried out by the author and others, was that considerable growth potential exists by simply increasing the physical size and capacity of conventional geosynchronous satellites while causing a minimal impact on existing ground systems and infrastructures. The work described here forms part of a power systems study carried out by Lockheed Martin Astro Space (Astro), and funded by the Department of Energy (DOE), to investigate how photovoltaic and reactor based power technology can be applied to spacecraft with payloads in the 20 kW to 100 kW range. The scope of this paper is to address how the payload type, power source technology and launch vehicle selection influence the physical characteristics of satellites with payloads of this magnitude.

  16. Systematic Relationships among Background SE U.S. Aerosol Optical, Micro-physical, and Chemical Properties-Development of an Optically-based Aerosol Characterization

    NASA Astrophysics Data System (ADS)

    Sherman, J. P.; Link, M. F.; Zhou, Y.

    2014-12-01

    Remote sensing-based retrievals of aerosol composition require known or assumed relationships between aerosol optical properties and types. Most optically-based aerosol classification schemes apply some combination of the spectral dependence of aerosol light scattering and absorption-using the absorption and either scattering or extinction Angstrom exponents (AAE, SAE and EAE), along with single-scattering albedo (SSA). These schemes can differentiate between such aerosol types as dust, biomass burning, and urban/industrial but no such studies have been conducted in the SE U.S., where a large fraction of the background aerosol is a variable mixture of biogenic SOA, sulfates, and black carbon. In addition, AERONET retrievals of SSA are often highly uncertain due to low AOD in the region during most months. The high-elevation, semi-rural AppalAIR facility at Appalachian State University in Boone, NC (1090m ASL, 36.210N, 81.690W) is home to the only co-located NOAA-ESRL and AERONET monitoring sites in the eastern U.S. Aerosol chemistry measured at AppalAIR is representative of the background SE U.S (Link et al. 2014) Dried aerosol light absorption and dried and humidified aerosol light scattering and hemispheric backscattering at 3 visible wavelengths and 2 particle size cuts (sub-1μm and sub-10μm) are measured continuously. Measurements of size-resolved, non-refractory sub-1μm aerosol composition were made by a co-located AMS during the 2012-2013 summers and 2013 winter. Systematic relationships among aerosol optical, microphysical, and chemical properties were developed to better understand aerosol sources and processes and for use in higher-dimension aerosol classification schemes. The hygroscopic dependence of visible light scattering is sensitive to the ratio of sulfate to organic aerosol(OA), as are SSA and AAE. SAE is a less sensitive indicator of fine-mode aerosol size than hemispheric backscatter fraction (b) and is more sensitive to fine-mode aerosol

  17. The physical and chemical characteristics of pulverized coal combustion ashes

    SciTech Connect

    Ozasa, Kazuo; Kamijo, Tsunao; Owada, Tetsuo; Hosoda, Nobumichi

    1999-07-01

    Japan is the world's largest consumer of coal. Most of it is imported from various countries around the world. While coal generates more CO{sub 2}, which contributes to the greenhouse effect more than other types of fuel, plans are being drawn up to depend more on coal energy in order to maintain diversity in energy sources. Production of coal ash will increase as a result. In Japan, therefore, the public and private sectors are active in both developing and implementing clean, efficient and effective coal utilization technologies. More than 100 types of coal are being burned in Japan at present. For example, a power generating plant burns 20 to 40 different types of coal annually. Since a single type or coal blended with several different types are burned in Japan, the properties of coal ash differ by consuming plant and season. Therefore, understanding coal ash characteristics based on various properties is essential to the effective utilization of coal. The center of Coal Utilization, Japan has researched and developed effective utilization of coal ash as a supplementary project of the Ministry of International Trade and Industry. Chemical, physical, soil, and leaching characteristics, which are fundamental to using pulverized coal ash as a civil engineering material in large quantities, were selected and are described in this report.

  18. A physically based framework for modeling the organic fractionation of sea spray aerosol from bubble film Langmuir equilibria

    NASA Astrophysics Data System (ADS)

    Burrows, S. M.; Ogunro, O.; Frossard, A. A.; Russell, L. M.; Rasch, P. J.; Elliott, S. M.

    2014-12-01

    The presence of a large fraction of organic matter in primary sea spray aerosol (SSA) can strongly affect its cloud condensation nuclei activity and interactions with marine clouds. Global climate models require new parameterizations of the SSA composition in order to improve the representation of these processes. Existing proposals for such a parameterization use remotely sensed chlorophyll a concentrations as a proxy for the biogenic contribution to the aerosol. However, both observations and theoretical considerations suggest that existing relationships with chlorophyll a, derived from observations at only a few locations, may not be representative for all ocean regions. We introduce a novel framework for parameterizing the fractionation of marine organic matter into SSA based on a competitive Langmuir adsorption equilibrium at bubble surfaces. Marine organic matter is partitioned into classes with differing molecular weights, surface excesses, and Langmuir adsorption parameters. The classes include a lipid-like mixture associated with labile dissolved organic carbon (DOC), a polysaccharide-like mixture associated primarily with semilabile DOC, a protein-like mixture with concentrations intermediate between lipids and polysaccharides, a processed mixture associated with recalcitrant surface DOC, and a deep abyssal humic-like mixture. Box model calculations have been performed for several cases of organic adsorption to illustrate the underlying concepts. We then apply the framework to output from a global marine biogeochemistry model, by partitioning total dissolved organic carbon into several classes of macromolecules. Each class is represented by model compounds with physical and chemical properties based on existing laboratory data. This allows us to globally map the predicted organic mass fraction of the nascent submicron sea spray aerosol. Predicted relationships between chlorophyll a and organic fraction are similar to existing empirical parameterizations

  19. Water soluble ions in aerosols (TSP) : Characteristics, sources and seasonal variation over the central Himalayas, Nepal

    NASA Astrophysics Data System (ADS)

    Tripathee, Lekhendra; Kang, Shichang; Zhang, Qianggong; Rupakheti, Dipesh

    2016-04-01

    Atmspheric pollutants transported from South Asia could have adverse impact on the Himalayan ecosystems. Investigation of aerosol chemistry in the Himalayan region in Nepal has been limited on a temporal and spatial scale to date. Therefore, the water-soluble ionic composition of aerosol using TSP sampler was investigated for a year period from April 2013 to March 2014 at four sites Bode, Dhunche, Lumbini and Jomsom characterized as an urban, rural, semi-urban and remote sites in Nepal. During the study period, the highest concentration of major cation was Ca2+ with an average concentration of 8.91, 2.17, 7.85 and 6.42 μg m-3 and the highest concentration of major anion was SO42- with an average of 10.96, 4.06, 6.85 and 3.30 μg m-3 at Bode, Dhunche, Lumbini and Jomsom respectively. The soluble ions showed the decrease in concentrations from urban to the rural site. Correlations and PCA analysis suggested that that SO42-, NO3- and NH4+ were derived from the anthropogenic sources where as the Ca2+ and Mg2+ were from crustal sources. Our results also suggest that the largest acid neutralizing agent at our sampling sites in the central Himalayas are Ca2+ followed by NH4+. Seasonal variations of soluble ions in aerosols showed higher concentrations during pre-monsoon and winter (dry-periods) due to limited precipitation amount and lower concentrations during the monsoon which can be explained by the dilution effect, higher the precipitation lower the concentration. K+ which is regarded as the tracer of biomss burning had a significant peaks during pre-monsoon season when the forest fires are active around the regions. In general, the results of this study suggests that the atmospheric chemistry is influenced by natural and anthropogenic sources. Thus, soluble ionic concentrations in aerosols from central Himalayas, Nepal can provide a useful database to assess atmospheric environment and its impacts on human health and ecosystem in the southern side of central

  20. Characteristics of the water-soluble components of aerosol particles in Hefei, China.

    PubMed

    Deng, Xue-liang; Shi, Chun-e; Wu, Bi-wen; Yang, Yuan-jian; Jin, Qi; Wang, Hong-lei; Zhu, Song; Yu, Caixia

    2016-04-01

    Size-classified daily aerosol mass concentrations and concentrations of water-soluble inorganic ions were measured in Hefei, China, in four representative months between September 2012 and August 2013. An annual average mass concentration of 169.09 μg/m(3) for total suspended particulate (TSP) was measured using an Andersen Mark-II cascade impactor. The seasonal average mass concentration was highest in winter (234.73 μg/m(3)) and lowest in summer (91.71 μg/m(3)). Water-soluble ions accounted for 59.49%, 32.90%, 48.62% and 37.08% of the aerosol mass concentration in winter, spring, summer, and fall, respectively, which indicated that ionic species were the primary constituents of the atmospheric aerosols. The four most abundant ions were NO3(-), SO4(2-), Ca(2+) and NH4(+). With the exception of Ca(2+), the mass concentrations of water-soluble ions were in an intermediate range compared with the levels for other Chinese cities. Sulfate, nitrate, and ammonium were the dominant fine-particle species, which were bimodally distributed in spring, summer and fall; however, the size distribution became unimodal in winter, with a peak at 1.1-2.1 μm. The Ca(2+) peak occurred at approximately 4.7-5.8 μm in all seasons. The cation to anion ratio was close to 1.4, which suggested that the aerosol particles were alkalescent in Hefei. The average NO3(-)/SO4(2-) mass ratio was 1.10 in Hefei, which indicated that mobile source emissions were predominant. Significant positive correlation coefficients between the concentrations of NH4(+) and SO4(2-), NH4(+) and NO3(-), SO4(2-) and NO3(-), and Mg(2+) and Ca(2+) were also indicated, suggesting that aerosol particles may be present as (NH4)2SO4, NH4HSO4, and NH4NO3. PMID:27090692

  1. Evaluation of IASI-derived dust aerosol characteristics over the tropical belt

    NASA Astrophysics Data System (ADS)

    Capelle, V.; Chédin, A.; Siméon, M.; Tsamalis, C.; Pierangelo, C.; Pondrom, M.; Crevoisier, C.; Crepeau, L.; Scott, N. A.

    2014-09-01

    IASI (Infrared Atmospheric Sounder Interferometer)-derived monthly mean infrared (10 μm) dust aerosol optical depth (AOD) and altitude are evaluated against ground-based Aerosol RObotic NETwork of sun photometers (AERONET) measurements of the 500 nm coarse-mode AOD and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) measurements of altitude at 38 AERONET sites (sea and land) within the tropical belt (30° N-30° S). The period covered extends from July 2007 to June 2013. The evaluation goes through the analysis of Taylor diagrams and box-and-whiskers plots, separating situations over oceanic regions and over land. For the AOD, such an evaluation raises the problem of the difference between the two spectral domains used: infrared for IASI and visible for AERONET. Consequently, the two measurements do not share the same metrics. For that reason, AERONET coarse-mode AOD is first "translated" into IASI-equivalent infrared AOD. This is done by the determination, site by site, of an infrared to visible AOD ratio. Because translating visible coarse-mode AOD into infrared AOD requires accurate knowledge of variables, such as the infrared refractive index or the particle size distribution, quantifying the bias between these two sources of AOD is not straightforward. This problem is detailed in this paper, in particular in Appendix A. For the sites over oceanic regions, the overall AOD temporal correlation comes to 0.86 for 786 items (IASI and AERONET monthly mean bins). The overall normalized standard deviation (i.e. ratio of the standard deviation of the test data (IASI) to that of the reference data (AERONET)) is 0.93, close to the desired value of 1. Over land, essentially desert, correlation is 0.74 for 619 items and the normalized standard deviation is 0.86. This slight but significant degradation over land most probably results from the greater complexity of the surface (heterogeneity, elevation) and, to a lesser extent, to the episodic presence of dust

  2. Aerosol physical and chemical properties retrieved from ground-based remote sensing measurements during heavy haze days in Beijing winter

    NASA Astrophysics Data System (ADS)

    Li, Z. Q.; Gu, X.; Wang, L.; Li, D.; Li, K.; Dubovik, O.; Schuster, G.; Goloub, P.; Zhang, Y.; Li, L.; Xie, Y.; Ma, Y.; Xu, H.

    2013-02-01

    With the development of economy in the past thirty years, many large cities in the eastern and southwestern China are experiencing increased haze events and atmospheric pollution, causing significant impacts on the regional environment and even climate. However, knowledge on the aerosol physical and chemical properties in heavy haze conditions is still insufficient. In this study, two winter heavy haze events in Beijing occurred in 2011 and 2012 were selected and investigated by using the ground-based remote sensing measurements. We used CIMEL CE318 sun-sky radiometer to derive haze aerosol optical, physical and chemical properties, including aerosol optical depth (AOD), size distribution, complex refractive indices and fractions of chemical components like black carbon (BC), brown carbon (BrC), mineral dust (DU), ammonium sulfate-like (AS) components and aerosol water content (AW). The retrieval results from a total of five haze days showed that the aerosol loading and properties during the two winter haze events were relatively stable. Therefore, a parameterized heavy haze characterization was drawn to present a research case for future studies. The averaged AOD is 3.2 at 440 nm and Ångström exponent is 1.3 from 440-870 nm. The coarse particles occupied a considerable fraction of the bimodal size distribution in winter haze events, with the mean particle radius of 0.21 and 2.9 μm for the fine and coarse mode respectively. The real part of the refractive indices exhibited a relatively flat spectral behavior with an average value of 1.48 from 440 to 1020 nm. The imaginary part showed obviously spectral variation with the value at 440 nm (about 0.013) higher than other three wavelengths (e.g. about 0.008 at 675 nm). The chemical composition retrieval results showed that BC, BrC, DU, AS and AW occupied 1%, 2%, 49%, 15% and 33% respectively on average for the investigated haze events. The comparison of these remote sensing results with in situ BC and PM2

  3. Optical, Physical and Chemical Properties of Tar Balls Observed During the Yosemite Aerosol Characterization Study

    SciTech Connect

    Hand, Jenny L.; Malm, W. C.; Laskin, Alexander; Day, D. E.; Lee, Tae-bum; Wang, Chong M.; Carrico, C. E.; Carrillo, John R.; Cowin, James P.; Collett, J. G.; Iedema, Martin J.

    2005-11-09

    The Yosemite Aerosol Characterization Study of summer 2002 (YACS) occurred during an active fire season in the western U. S., and provided an opportunity to investigate many unresolved issues related to the radiative effects of biomass burning aerosols. Single particle analysis was performed on field collected aerosol samples using an array of electron microscopy techniques. Amorphous carbon spheres, or “tar balls”, were present in samples collected during episodes of high particle light scattering coefficients that occurred during the peak of a smoke/haze event. The highest concentrations of light-absorbing carbon from a dual-wavelength aethalometer (λ = 370 and 880 nm) occurred during periods when the particles were predominantly tar balls, indicating they do absorb light in the UV and near-IR range of the solar spectrum. Closure experiments of mass concentrations and light scattering coefficients during periods dominated by tar balls did not require any distinct assumptions of organic carbon molecular weight correction factors, density, or refractive index compared to periods dominated by other types of organic carbon aerosols. Measurements of the hygroscopic behavior of tar balls using an environmental SEM indicate that tar balls do not exhibit deliquescence, but do uptake some water at high (~83 %) relative humidity. The ability of tar balls to efficiently scatter and absorb light, and to absorb water has important implications for their role in regional haze and climate fence.

  4. Chemical and Aerosol Characteristics of Asian Outflow as Observed during INTEX-B and TRACE-P

    NASA Astrophysics Data System (ADS)

    Thornhill, L.; Anderson, B. E.; Winstead, E. L.; Chen, G.; Clarke, A.; Dibb, J.; Scheuer, E.; Sachse, G.; Blake, D.; Fuelberg, H.

    2007-12-01

    The NASA Intercontinental Transport and Chemistry Experiment, phase B (INTEX-B) was conducted in the spring of 2006 to investigate the transport and transformation of gases and aerosols on transcontinental/intercontinental scales and to assess the impacts of the aged pollutants on air quality and climate. To accomplish these goals, the instrumented, North Dakota DC-8 aircraft was deployed during two separate phases to study vastly different pollution and transport phenomena. During the first 3 weeks of March, the aircraft was based in Houston and flew sorties over Mexico City and the western Gulf to examine the composition, outflow pathways, and evolution of pollution from Mexico City. The second phase took place between April 17 and May 15, and involved basing the aircraft at first Hickam AFB, Hawaii, then Anchorage, AK to examine the outflow of pollution from Asia at different points along the transport pathway. In this presentation, we analyze data from the second phase of INTEX-B to characterize the composition of Asian outflow as a function of age (e.g. C2H2/CO ratio) and vertical location (0-2, 2-4, 4-6, 6-8, and >8 km). We use airmass trajectories to identify the primary Asian continental source regions that influence atmospheric composition within the Northeast Pacific region and characterize those source regions using aerosol and gas phase tracers. In addition, we compare INTEX-B vertical profiles of trace gas and aerosol species with similar measurements recorded aboard the DC-8 just off the Asian coast during the 2001 NASA Transport and Chemistry near the Equator - Pacific (TRACE-P) experiment to evaluate changes in species concentrations/characteristics during the approximately 10-day transport period between the two regions.

  5. Characteristics of wintertime polycyclic aromatic hydrocarbon assemblage in aerosol of the Southern Adriatic

    NASA Astrophysics Data System (ADS)

    Jovanović, V. Ž.; Pfendt, P. A.; Filipović, A. J.

    2007-09-01

    Features of polycyclic aromatic hydrocarbon (PAH) assemblage in aerosol samples collected from the atmosphere of Herceg Novi during the winter months of two successive years were studied. The results showed almost the same concentration profiles of identified PAHs for samples from the two periods analyzed, generally suggesting a similar origin. Diagnostic ratios indicated combustion of wood and coal, emissions from petrol and diesel engines, and dust resuspension as sources that predominantly contributed to the atmospheric PAH concentrations. Statistical analysis, principal component analysis (PCA) in particular, allowed us to identify the impact of meteorological parameters on PAH abundance.

  6. Aerosol Abundances and Optical Characteristics in the Pacific Basin Free Troposphere

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Livingston, J. M.; Ferry, G. V.; deFelice, T. E.

    1994-01-01

    During NASA's Global Backscatter Experiment (GLOBE) mission flights in November 1989 and May 1990, a DC-8 research aircraft probed the Pacific Basin free troposphere for about 90 flight hours in each month between +72 and -62 degrees latitude, +130 and -120 degrees longitude, and up to 39,000 feet pressure altitudes. Aerosols were sampled continuously in situ by optical particle counters to measure concentration and particle size, and during 48 10-min intervals during each mission by wire impactors for concentration, size, composition, phase and shape analyses. The optical particle counters cover a particle diameter range between 0.3 and 20 microns; wire impactors extend the range down to 0.03 microns. Results of particle number, size, shape, together with the assumption of a refractive index corresponding to (NH4)2SO4 to account for the prevalence of aerosol sulfur, were utilized in a Mie algorithm to calculate aerosol extinction and backscatter for a range of wavelengths (0.385 less than lambda less than 10.64 microns). Computations for 22 randomly selected size distributions yield coefficients of extinction E(0.525) = (2.03 +/- 1.20) x 10(exp -4) km(exp -1) and backscatter beta(0.525) = (6.45 +/- 3.49) x 10(exp -6) km(exp -1) sr(exp -1) in the visible, and E(10.64) = (8.13 +/- 6.47) x 10(exp -6) km(exp -1) and beta(10.64) = (9.98 +/- 10.69) x 10(exp -8) km(exp -1) sr(exp -1) in the infrared, respectively. Large particles (D greater than 0.3 microns) contribute two-thirds to the total extinction in the visible (lambda = 0.525 microns), and almost 100% in the infrared (lambda = 10.64 microns). These results have been used to define an IR optical aerosol climatology of the Pacific Basin free troposphere, from which it follows that the infrared backscatter coefficient at lambda = 9.25 microns wavelength fluctuates between 5.0 x 10(exp -10) and 2.0 x 10(exp -7) km(exp -1) sr(exp -1) with a modal value 2.0 x 10(exp -8) km(exp -1) sr(exp -1).

  7. Aerosol and gas-phase characteristics in relation to meteorology: Case studies in populated arid settings

    NASA Astrophysics Data System (ADS)

    Crosbie, Ewan Colin

    Atmospheric aerosols and trace gases are a highly relevant component of the climate system affecting atmospheric radiative transfer and the hydrologic cycle. In arid and semi-arid regions, where cloud cover is often low and precipitation is generally scarce and sporadic, the driving processes accounting for the production, loss and transport of atmospheric constituents are often distinctly different from other climates. In arid regions, the same circulation dynamics that suppress cloud formation can be responsible for creating strong subsidence inversions, which cap atmospheric mixing and trap pollutants close to the surface, often placing populated arid regions high on global rankings of air pollution concerns. In addition, low soil moisture can encourage wind-blown dust emissions, which can be a significant fraction of the total aerosol loading in both coarse and fine modes on a mass basis. Three distinct focus regions are investigated over varying time scales, using a diverse set of techniques, and with wide-ranging primary goals. 1) the Tehran metropolitan area in Iran over a ten-year period from 2000-2009, 2) Tucson, Arizona over 2012-2014 with three intensive monitoring periods during summer 2014 and winter 2015 and 3) the San Joaquin Valley in California during the NASA DISCOVER-AQ campaign during Jan-Feb 2013. However, in all cases, local and regional scale meteorology play a significant role in controlling the spatiotemporal variability in trace gas and aerosol concentrations. Particular emphasis is placed on understanding transport pathways due to the local wind patterns and the importance of key meteorological parameters such as temperature, humidity and solar radiation on controlling production and loss mechanisms. While low in magnitude, the precipitation pattern is still an important sink mechanism that modulates gas phase and particle abundances in all three regions, either through scavenging or by promoting vertical mixing. The reported measurements

  8. The Relationship between Physical Therapist Assistant Faculty Characteristics and Program Outcomes on the National Physical Therapy Examination

    ERIC Educational Resources Information Center

    Novak, Malorie Kosht

    2009-01-01

    Background. There is a paucity of published literature regarding the correlation between faculty characteristics and outcomes on the National Physical Therapy Examination for Physical Therapist Assistants (NPTE-PTA). Purpose. To determine if there was a relationship between faculty characteristics in PTA educational programs and program outcomes…

  9. A study of the physical, chemical, and optical properties of ambient aerosol particles in Southeast Asia during hazy and nonhazy days

    NASA Astrophysics Data System (ADS)

    See, S. W.; Balasubramanian, R.; Wang, W.

    2006-05-01

    Many Southeast Asian countries have been constantly plagued by recurring smoke haze episodes as a result of traditional slash-and-burn practices in agricultural areas to clear crop lands or uncontrolled forest fires. However, our current knowledge on the physiochemical and optical properties of ambient aerosols associated with regional haze phenomenon is still fairly limited. Therefore a comprehensive field study was carried out in Singapore from March 2001 to March 2002 under varying weather conditions to gain a better understanding of the characteristics. The physical (size distribution of mass and number concentrations), chemical (mass concentrations of chemical components: 14 ions, 24 metals, elemental carbon (EC) and organic carbon (OC)), and optical (light absorption (bap) and scattering (bsp) by particles) characteristics of ambient aerosol particles were investigated. The results are reported separately for clear and hazy days by categorizing the days as clear or hazy on the basis of visibility data. It was observed that the average concentrations of PM2.5 and most chemical components increased approximately by a factor of 2 on hazy days. Backward air trajectories together with the hot spot distributions in the region indicated that the degradation in Singapore's air quality on hazy days was attributable to large-scale forest fires in Sumatra. This visibility degradation was quantitatively measured on the basis of the light absorption and scattering by particles. As expected, scattering rather than absorption controlled atmospheric visibility, and PM2.5 particles present on hazy days were more efficient at scattering light than those found on clear days.

  10. Summer-winter differences in the relationships among background southeastern U.S. aerosol optical, micro-physical, and chemical properties

    NASA Astrophysics Data System (ADS)

    Sherman, J. P.; Link, M.; Zhou, Y.

    2015-12-01

    Relationships among aerosol optical, micro-physical, and chemical properties are useful for evaluating regional climate models, developing satellite-based aerosol retrievals, and understanding aerosol sources and processes. Since aerosol loading and optical properties vary primarily on seasonal scales in the southeastern U.S., it is important that such studies be carried out over multiple seasons but few (if any) such multi-season studies have been conducted in the region. The high-elevation, semi-rural AppalAIR facility at Appalachian State University in Boone, NC (1080m ASL, 36.210N, 81.690W) is home to the only co-located NOAA-ESRL and AERONET monitoring sites in the eastern U.S. Measurements of size-resolved, non-refractory sub-1μm aerosol composition were also made by a co-located AMS during the 2012-2013 summers and 2013 winter. Systematic relationships among aerosol optical, microphysical, and chemical properties were developed to better understand aerosol sources and processes and for use in higher-dimension aerosol classification schemes. Some of the major findings will be presented. Higher values of lower tropospheric aerosol light scattering coefficient at 550nm (a proxy for aerosol loading) are associated with higher single-scattering albedo (SSA) and lower hemispheric backscatter fraction (b) during both summer and winter. Absorption Angstrom exponent (AAE) is typically well under 1 during summer and near 1.3-1.4 during winter. Lowest summer AAE values coincide with large, highly-reflective particles and higher aerosol light scattering coefficient but summer AAE is only weakly anti-correlated with organic and sulfate mass concentrations. Winter AAE is consistent with a mixture of elemental carbon and light-absorbing organic carbon, possibly influenced by regional residential wood-burning during winter. The hygroscopic dependence of visible light scattering is sensitive to sulfate and organic aerosol mass fractions during both summer and winter

  11. Oak Ridge Reservation Physical Characteristics and Natural Resources

    SciTech Connect

    Parr, P.D.; Hughes, J.F.

    2006-09-19

    The topography, geology, hydrology, vegetation, and wildlife of the Oak Ridge Reservation (ORR) provide a complex and intricate array of resources that directly impact land stewardship and use decisions (Fig. 1). The purpose of this document is to consolidate general information regarding the natural resources and physical characteristics of the ORR. The ORR, encompassing 33,114 acres (13,401 ha) of federally owned land and three Department of Energy (DOE) installations, is located in Roane and Anderson Counties in east Tennessee, mostly within the corporate limits of the city of Oak Ridge and southwest of the population center of Oak Ridge. The ORR is bordered on the north and east by the population center of the city of Oak Ridge and on the south and west by the Clinch River/Melton Hill Lake impoundment. All areas of the ORR are relatively pristine when compared with the surrounding region, especially in the Valley and Ridge Physiographic Province (Fig. 2). From the air, the ORR is clearly a large and nearly continuous island of forest within a landscape that is fragmented by urban development and agriculture. Satellite imagery from 2006 was used to develop a land-use/land-cover cover map of the ORR and surrounding lands (Fig. 3). Following the acquisition of the land comprising the ORR in the early 1940s, much of the Reservation served as a buffer for the three primary facilities: the X-10 nuclear research facility (now known as the Oak Ridge National Laboratory [ORNL]), the first uranium enrichment facility or Y-12 (now known as the Y-12 National Security Complex [Y-12 Complex]), and a gaseous diffusion enrichment facility (now known as the East Tennessee Technology Park [ETTP]). Over the past 60 years, this relatively undisturbed area has evolved into a rich and diverse eastern deciduous forest ecosystem of streams and reservoirs, hardwood forests, and extensive upland mixed forests. The combination of a large land area with complex physical characteristics

  12. Physical Layer Characteristics and Techniques for Visible Light Communications

    NASA Astrophysics Data System (ADS)

    Cui, Kaiyun

    With the rapid development of semiconductor lighting technologies, the light emitting diodes (LEDs) are promising to eventually replace traditional incandescent and fluorescent lamps for their high energy efficiency, environmental friendliness, and long lifetime. Visible light communication (VLC) utilizing lighting LEDs as transmitters has been an emerging research area since its first proposal. Ubiquitous communication coverage will become possible with wide deployment of lighting LEDs. This thesis studies physical layer characteristics of VLC systems based on either indoor LED lighting or outdoor LED traffic signaling infrastructure. Advanced communication techniques are proposed to cope with LED bandwidth limitations and grant multiple accesses. Their performance is comprehensively analyzed in typical lighting and signaling environments. Firstly, communication link issues are studied. A conversion method from photometric parameters for illumination to radiometric parameters for communication is developed. Two typical VLC links, the line-of-sight (LOS) link and non-line-of-sight (NLOS) diffuse link, are characterized both experimentally and numerically. Some optional reverse link provisions are evaluated for a full duplex system. Different noise sources and background interferences are analyzed, and dominant noises are identified under typical application scenarios. With identified signal propagation and noise characteristics, link performance is then evaluated. Secondly, transceiver design techniques to increase the data rate are proposed, including digital pre-equalization techniques and the optical orthogonal frequency division multiplexing (O-OFDM) whose peak to average power ratio (PAPR) issue is investigated. Thirdly, the capacity of the multiple-input multiple-output (MIMO) VLC system exploring inherent multiple LED transmitters and multiple photodetectors is evaluated. The effects of some system parameters involved in non-imaging and imaging transceivers

  13. Physical and chemical characteristics of goldenberry fruit (Physalis peruviana L.).

    PubMed

    Yıldız, Gökçen; İzli, Nazmi; Ünal, Halil; Uylaşer, Vildan

    2015-04-01

    Some physical and chemical characteristics of goldenberry fruit (Physalis peruviana L.) were investigated. These characteristics are necessary for the design of equipments for harvesting, processing, transportation, sorting, separating and packing. The fruit length, diameter, geometric and arithmetic mean diameters, sphericity, surface area, projected areas (vertical-horizontal) and aspect ratio of goldenberries were determined as 17.52 mm, 17.31 mm, 17.33 mm, 17.38 mm, 98.9 %, 0.949 cm(2), 388.67-387.85 mm(2) and 0.988, respectively. The mass of fruit, bulk density, fruit density, porosity and fruit hardness were 3.091 g, 997.3 kg/m(3), 462.3 kg/m(3), 53.61 % and 8.01 N, respectively. The highest static coefficient of friction was observed on rubber surface, followed by stainless steel sheet, aluminum sheet, and plywood materials. The dry matter, water soluble dry matter, ash, protein, oil, carbohydrate, titratable acidity, pH, total sugar, reducing sugar, antioxidant capacity were 18.67 %, 14.17 %, 2.98 %, 1.66 %, 0.18 %, 13.86 %, 1.26 %, 6.07, 63.90 g/kg, 31.99 g/kg and 57.67 %, respectively. The fresh fruits have 145.22 mg gallic acid equivalent (GAE)/100 g total phenol content and skin colour data represented as L*, a*, b*, Chroma (C) and Hue angle (α) were 49.92, 25.11, 50.23, 56.12 and 63.48, respectively. PMID:25829615

  14. Measurement of aerosol chemical, physical and radiative properties in the Yangtze delta region of China

    NASA Astrophysics Data System (ADS)

    Xu, Jin; Bergin, M. H.; Yu, X.; Liu, G.; Zhao, J.; Carrico, C. M.; Baumann, K.

    In order to understand the possible influence of aerosols on the environment in the agricultural Yangtze delta region of China, a one-month field sampling campaign was carried out during November 1999 in Linan, China. Measurements included the aerosol light scattering coefficient at 530 nm, σsp, measured at both dry relative humidity (RH<40%) and under ambient conditions (sample RH=63±19%), and the absorption coefficient at 565 nm, σap, for aerosol particles having diameters <2.5 μm (PM 2.5). At the same time, daily filter samples of PM 2.5 as well as aerosol particles having diameters <10 μm (PM 10) were collected and analyzed for mass, major ion, organic compound (OC), and elemental carbon (EC) concentrations in order to determine which anthropogenic chemical species were primarily responsible for aerosol light extinction. The aerosol loading in the rural Yangtze delta region was comparable to highly polluted urban areas, with mean and standard deviation (S.D.) values for σsp, σap and PM 2.5 of 353 Mm -1 (202 Mm -1), 23 Mm -1 (14 Mm -1) and 90 μg m -3 (47 μg m -3), respectively. A clear diurnal pattern was observed in σsp and σap with minimum values occurring in the middle of the day, most likely associated with the maximum midday mixing height. The ratio of the change in light scattering coefficient at ambient RH to that at controlled RH (RH<40%), Fσsp (RH), indicates that condensed water typically contributed ˜40% to the light scattering budget in this region. The mass scattering efficiency of the dry aerosol, E scat_2.5, and mass absorption efficiency of EC, E abs_2.5, have mean and S.D. values of 4.0 m 2 g -1 (0.4 m 2 g -1) and 8.6 m 2 g -1 (7.0 m 2 g -1), respectively. PM 2.5 concentrations in Linan and two other locations in the Yangtze delta, Sheshan and Changshu (which have monthly mean values ranging from ˜80 to 110 μg m -3), are all significantly higher than the proposed 24-h average US PM 2.5 NAAQS of 65 μg m -3. Organic compounds are

  15. Characteristics of carbonaceous aerosols emitted from peatland fire in Riau, Sumatra, Indonesia (2): Identification of organic compounds

    NASA Astrophysics Data System (ADS)

    Fujii, Yusuke; Kawamoto, Haruo; Tohno, Susumu; Oda, Masafumi; Iriana, Windy; Lestari, Puji

    2015-06-01

    Smoke emitted from Indonesian peatland fires has caused dense haze and serious air pollution in Southeast Asia such as visibility impairment and adverse health impacts. To mitigate the Indonesian peatland fire aerosol impacts, an effective strategy and international framework based on the latest scientific knowledge needs to be established. Although several attempts have been made, limited data exist regarding the chemical characteristics of peatland fire smoke for the source apportionment. In order to identify the key organic compounds of peatland fire aerosols, we conducted intensive field studies based on ground-based and source-dominated sampling of PM2.5 in Riau Province, Sumatra, Indonesia, during the peatland fire seasons in 2012. Levoglucosan was the most abundant compound among the quantified organic compounds at 8.98 ± 2.28% of the PM2.5 mass, followed by palmitic acid at 0.782 ± 0.163% and mannosan at 0.607 ± 0.0861%. Potassium ion was not appropriate for an indicator of Indonesian peatland fires due to extremely low concentrations associated with smoldering fire at low temperatures. The vanillic/syringic acids ratio was 1.06 ± 0.155 in this study and this may be a useful signature profile for peatland fire emissions. Particulate n-alkanes also have potential for markers to identify impact of Indonesian peatland fire source at a receptor site.

  16. Chemical characteristics of ambient aerosols contributed by cooking process at Noorpur village near Delhi (India)

    NASA Astrophysics Data System (ADS)

    Singh, Sudha; Kumar, Bablu; Gupta, Gyan Prakash; Kulshrestha, U. C.

    2013-05-01

    Combustion of fuels such as wood, crop residue and dung cakes etc. is one of the major sources of air pollution in developing countries. These fuels are still used commonly for cooking purpose in rural India. This study investigates the chemical composition of the ambient aerosols during cooking hours at a village called Noorpur (28.470 N, 77.030 E) which lies near Delhi city. Aerosol sampling was carried out during August 2011-May 2012 by using handy sampler (Envirotech model APM 821) installed at the terrace of a building (˜6m). The samples were collected on 8 hourly basis using Teflon filters. The water extract of these filters was analyzed for major anions (F-, Cl-, NO3-, SO42-) and major cations (Na+, NH4+, K+, Ca2+ Mg2+) by ion chromatography (Metrohm 883 Basic IC Plus). Results highlighted that cooking process contributed significant amount of SO42- and K+ṡ. Biomass burning is considered as a potential source of K+ in air. The high concentration of SO42- might be due to oxidation of SO2 contributed by the combustion of dung cakes. Further, the detailed results will be discussed during the conference.

  17. [Study on pollution characteristics of carbonaceous aerosols in Xi'an City during the spring festival].

    PubMed

    Zhou, Bian-Hong; Zhang, Cheng-Zhong; Wang, Ge-Hui

    2013-02-01

    The samples of PM2.5 with 8 times periods were collected using Automated Cartridge Collection Unit (ACCU) of Rupprecht& Patashnick (R&P)Corporation, and monitored by R&P1400a instrument of TEOM series online during 2011 Spring Festival in Xi'an city. The organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and water-insoluble organic carbon (WIOC) contents of 3 h integrated PM2.5 were analyzed to evaluate the influence of firework display on the carbonaceous components in urban air. The mass concentration of PM2.5 was found increased significantly from 00:00 A. M. to 02:59 A. M. at the Chinese Lunar New Year's Eve than the non-firework periods, reaching 1514.8 microg.m-3 at 01:00 A. M. The mass concentrations of OC, EC, WSOC, and WIOC during the same time period were 123.3 microg.m-3, 18.6 microg.m-3, 66.7 microg.m-3, and 56.6 microg.m-3, about 1.7, 1.2, 1.4, and 2.2 times higher than the average in normal days, respectively. Correlation analysis among WSOC, OC, and EC contents in PM25 showed that firework emission was an obvious source of carbonaceous aerosol in the Spring Festival vacation. However, it only contributes to 9. 4% for aerosol in fireworks emission. PMID:23668108

  18. Characteristics of black carbon aerosol from a surface oil burn during the Deepwater Horizon oil spill

    NASA Astrophysics Data System (ADS)

    Perring, A. E.; Schwarz, J. P.; Spackman, J. R.; Bahreini, R.; de Gouw, J. A.; Gao, R. S.; Holloway, J. S.; Lack, D. A.; Langridge, J. M.; Peischl, J.; Middlebrook, A. M.; Ryerson, T. B.; Warneke, C.; Watts, L. A.; Fahey, D. W.

    2011-09-01

    Black carbon (BC) aerosol mass mixing ratio and microphysical properties were measured from the NOAA P-3 aircraft during active surface oil burning subsequent to the Deepwater Horizon oil rig explosion in April 2010. Approximately 4% of the combusted material was released into the atmosphere as BC. The total amount of BC introduced to the atmosphere of the Gulf of Mexico via surface burning of oil during the 9-week spill is estimated to be (1.35 ± 0.72) × 106 kg. The median mass diameter of BC particles observed in the burning plume was much larger than that of the non-plume Gulf background air and previously sampled from a variety of sources. The plume BC particles were internally mixed with very little non-refractory material, a feature typical of fresh emissions from fairly efficient fossil-fuel burning sources and atypical of BC in biomass burning plumes. BC dominated the total accumulation-mode aerosol in both mass and number. The BC mass-specific extinction cross-section was 10.2 ± 4.1 and 7.1 ± 2.8 m2/g at 405 and 532 nm respectively. These results help constrain the properties of BC emissions associated with DWH and other large spills.

  19. Carbonaceous aerosol characteristics over a Pinus taeda plantation: Results from the CELTIC experiment

    NASA Astrophysics Data System (ADS)

    Geron, Chris

    2011-01-01

    Carbonaceous particles smaller than 2.5 μm aerodynamic diameter (PM 2.5) were collected in July, 2003 over a Loblolly Pine plantation at Duke Forest, NC during the Chemical Emission, Loss, Transformation and Interactions within Canopies (CELTIC) field study. Organic (OC) and elemental (EC) carbon in PM 2.5 ranged from 1.4-6.3 and 0.08-0.41 μg C m -3, respectively, and concentrations measured above and below the pine canopy were in good agreement. Ambient OC was lower (<3 μg C m -3) during cooler periods (daytime maximum temperatures < 28 °C) and for periods following precipitation events, and was higher (>3 μg C m -3) during warm humid periods. Radiocarbon analysis indicates that on average 83% (range 78-91%) of the PM 2.5 carbon was derived from contemporary (biogenic VOC and biomass burning) sources. This is higher than previous estimates from urban and suburban sites, and in good agreement with recently published data from other rural sites throughout the U.S. The estimates of contemporary PM 2.5 carbon may represent a lower limit for this site since the sampler was located above the center of a 30 meter diameter plot fumigated with 200 ppm CO 2 derived from fossil carbon sources. However, this effect is likely to be negligible. The regression relationship between OC/EC ratios and percent biogenic carbon in aerosol is very similar to those observed in recent summertime data from Tennessee and Florida. However, our values for both OC/EC and percent biogenic carbon are higher than those observed in the latter studies, likely due to the more rural character of the site. Simple box model estimates indicate that biogenic VOC (BVOC) emissions measured at the site provide sufficient reactive carbon sources to account for the observed levels of aerosol biogenic carbon. The magnitude and temporal pattern in the box model secondary organic aerosol estimates correlate well with the ambient aerosol carbon measurements. The model estimates of the relative contribution

  20. Chemical characteristics of size-resolved aerosols from Asian dust and haze episode in Seoul Metropolitan City

    NASA Astrophysics Data System (ADS)

    Kang, Eunha; Han, Jihyun; Lee, Meehye; Lee, Gangwoong; Kim, Jong Chun

    2013-06-01

    We collected aerosol particles in Seoul using a 10 stage Micro-Orifice Uniform Deposit Impactor (MOUDI) to investigate the size distributions of aerosol mass and water-soluble inorganic ions (Na+, NH4+, K+, Mg2 +, Ca2 +, Cl-, NO3-, and SO42 -) for the two high-mass episodes taking place in February and April, 2009. The former was a heavy Asian dust (AD) event and the latter was a haze episode associated with stagnant condition that prevailed over the Yellow Sea region. In AD plume, the mass peak was noticeable at coarse mode between 1.0 and 1.8 μm but SO42 - and NH4+ were enriched in condensation mode between 0.056 and 0.1 μm. There was little chance for the heavy AD plume to pick up SO2 and water vapor, which are in good accordance with its transport paths and the chemical characteristics of aerosols and gaseous species. These results imply that the heterogeneous reaction of SO2 on dust particles would not be substantial in determining sulfate concentrations for this particular type of dust plume, considering the possibility of loss of large soil particles in MOUDI. During the haze episode, both total aerosol mass and water-soluble inorganic ions showed bimodal size distributions with the droplet (0.32-0.56 μm) and coarse (1.0-1.8 μm) mode peaks. In this haze event, acidic gases tend to be dissolved more efficiently in larger particles, shifting the peaks of SO42 - and NO3- to larger droplet particles. For NH4+, however, the mode change was not observed, which was probably due to the depleted source and high solubility of NH3. These results demonstrated that the availability of precursor gases such as SO2, NO2, and NH3, and the water-vapor contents were important factor to determine the formation of droplet-mode particles and their sizes.

  1. A Physically Based Framework for Modelling the Organic Fractionation of Sea Spray Aerosol from Bubble Film Langmuir Equilibria

    SciTech Connect

    Burrows, Susannah M.; Ogunro, O.; Frossard, Amanda; Russell, Lynn M.; Rasch, Philip J.; Elliott, S.

    2014-12-19

    The presence of a large fraction of organic matter in primary sea spray aerosol (SSA) can strongly affect its cloud condensation nuclei activity and interactions with marine clouds. Global climate models require new parameterizations of the SSA composition in order to improve the representation of these processes. Existing proposals for such a parameterization use remotely-sensed chlorophyll-a concentrations as a proxy for the biogenic contribution to the aerosol. However, both observations and theoretical considerations suggest that existing relationships with chlorophyll-a, derived from observations at only a few locations, may not be representative for all ocean regions. We introduce a novel framework for parameterizing the fractionation of marine organic matter into SSA based on a competitive Langmuir adsorption equilibrium at bubble surfaces. Marine organic matter is partitioned into classes with differing molecular weights, surface excesses, and Langmuir adsorption parameters. The classes include a lipid-like mixture associated with labile dissolved organic carbon (DOC), a polysaccharide-like mixture associated primarily with semi-labile DOC, a protein-like mixture with concentrations intermediate between lipids and polysaccharides, a processed mixture associated with recalcitrant surface DOC, and a deep abyssal humic-like mixture. Box model calculations have been performed for several cases of organic adsorption to illustrate the underlying concepts. We then apply the framework to output from a global marine biogeochemistry model, by partitioning total dissolved organic carbon into several classes of macromolecule. Each class is represented by model compounds with physical and chemical properties based on existing laboratory data. This allows us to globally map the predicted organic mass fraction of the nascent submicron sea spray aerosol. Predicted relationships between chlorophyll-\\textit{a} and organic fraction are similar to existing empirical

  2. Physical characteristics of various lasers used in stapes surgery.

    PubMed

    Frenz, Martin

    2007-01-01

    The invention of modern small-fenestra stapedotomy procedures using a piston-type prosthesis resulted in a remarkable hearing improvement and at the same time in a reduction of complications compared to conventionally performed stapedectomies. These procedures, however, still contain unpredictable risks such as uncontrolled stapes fracturing, luxation of the stapes or creating a floating footplate, which all can cause hearing loss or even deafness. The worldwide use of the small-fenestration techniques led to the observation that most cases of sensorineural hearing loss occurring after surgery were due to intraoperative trauma to the inner ear, most commonly during footplate manipulation. This led to the use of lasers in otological surgery as a possible tool for precise noncontact cutting of bone without any drill vibration. Today, argon, KTP, CO(2) and Er:YAG lasers are clinically used in middle ear surgery. Each laser has its characteristic interaction process with bone with its specific advantages and disadvantages. Therefore, it is not surprising that there are conflicting and controversially discussed experimental and clinical reports. The purpose of this study was to comprehensively compare the physical processes underlying the laser-tissue interaction of the different laser systems in view of safety and efficacy in order to enhance the ability to perform safe minimally invasive surgery on the stapes footplate. PMID:17245054

  3. Triplicity and physical characteristics of Asteroid (216) Kleopatra

    NASA Astrophysics Data System (ADS)

    Descamps, P.; Marchis, F.; Berthier, J.; Emery, J. P.; Duchêne, G.; de Pater, I.; Wong, M. H.; Lim, L.; Hammel, H. B.; Vachier, F.; Wiggins, P.; Teng-Chuen-Yu, J.-P.; Peyrot, A.; Pollock, J.; Assafin, M.; Vieira-Martins, R.; Camargo, J. I. B.; Braga-Ribas, F.; Macomber, B.

    2011-02-01

    To take full advantage of the September 2008 opposition passage of the M-type Asteroid (216) Kleopatra, we have used near-infrared adaptive optics (AO) imaging with the W.M. Keck II telescope to capture unprecedented high resolution images of this unusual asteroid. Our AO observations with the W.M. Keck II telescope, combined with Spitzer/IRS spectroscopic observations and past stellar occultations, confirm the value of its IRAS radiometric radius of 67.5 km as well as its dog-bone shape suggested by earlier radar observations. Our Keck AO observations revealed the presence of two small satellites in orbit about Kleopatra (see Marchis, F. et al. [2008a]. (3749) Balam. In: Green, D.W.E. (Ed.), IAU Circ. 8928; Marchis, F., Descamps, P., Berthier, J., Emery, J.P. [2008b]. S/2008 ((216)) 1 and S/2008 ((216)) 2. In: Green, D.W.E. (Ed.), IAU Circ. 8980). Accurate measurements of the satellite orbits over a full month enabled us to determine the total mass of the system to be 4.64 ± 0.02 × 10 18 kg. This translates into a bulk density of 3.6 ± 0.4 g/cm 3, which implies a macroscopic porosity for Kleopatra of ˜30-50%, typical of a rubble-pile asteroid. From these physical characteristics we measured its specific angular momentum, very close to that of a spinning equilibrium dumbbell.

  4. Physical Properties of Ambient and Laboratory-Generated Secondary Organic Aerosol

    SciTech Connect

    O'Brien, Rachel E.; Neu, Alexander; Epstein, Scott A.; MacMillan, Amanda; Wang, Bingbing; Kelly, Stephen T.; Nizkorodov, Sergey; Laskin, Alexander; Moffet, Ryan C.; Gilles, Mary K.

    2014-06-17

    The size and thickness of organic aerosol particles collected by impaction in five field campaigns were compared to those of laboratory generated secondary organic aerosols (SOA). Scanning transmission x-ray microscopy (STXM) was used to measure the total carbon absorbance (TCA) by individual particles as a function of their projection areas on the substrate. Because they flatten less upon impaction, particles with higher viscosity and surface tension can be identified by a steeper slope on a plot of TCA vs. size. The slopes of the ambient data are statistically similar indicating a small range of average viscosities and surface tensions across five field campaigns. Steeper slopes were observed for the plots corresponding to ambient particles, while smaller slopes were indicative of the laboratory generated SOA. This comparison indicates that ambient organic particles have higher viscosities and surface tensions than those typically generated in laboratory SOA studies.

  5. Physical Investigations of Small Particles: (I) Aerosol Particle Charging and Flux Enhancement and (II) Whispering Gallery Mode Sensing

    NASA Astrophysics Data System (ADS)

    Lopez-Yglesias, Xerxes

    Part I: Particles are a key feature of planetary atmospheres. On Earth they represent the greatest source of uncertainty in the global energy budget. This uncertainty can be addressed by making more measurement, by improving the theoretical analysis of measurements, and by better modeling basic particle nucleation and initial particle growth within an atmosphere. This work will focus on the latter two methods of improvement. Uncertainty in measurements is largely due to particle charging. Accurate descriptions of particle charging are challenging because one deals with particles in a gas as opposed to a vacuum, so different length scales come into play. Previous studies have considered the effects of transition between the continuum and kinetic regime and the effects of two and three body interactions within the kinetic regime. These studies, however, use questionable assumptions about the charging process which resulted in skewed observations, and bias in the proposed dynamics of aerosol particles. These assumptions affect both the ions and particles in the system. Ions are assumed to be point monopoles that have a single characteristic speed rather than follow a distribution. Particles are assumed to be perfect conductors that have up to five elementary charges on them. The effects of three body interaction, ion-molecule-particle, are also overestimated. By revising this theory so that the basic physical attributes of both ions and particles and their interactions are better represented, we are able to make more accurate predictions of particle charging in both the kinetic and continuum regimes. The same revised theory that was used above to model ion charging can also be applied to the flux of neutral vapor phase molecules to a particle or initial cluster. Using these results we can model the vapor flux to a neutral or charged particle due to diffusion and electromagnetic interactions. In many classical theories currently applied to these models, the finite size

  6. Physical and optical properties of mineral dust aerosol during the Dust and Biomass-burning Experiment

    NASA Astrophysics Data System (ADS)

    Osborne, S. R.; Johnson, B. T.; Haywood, J. M.; Baran, A. J.; Harrison, M. A. J.; McConnell, C. L.

    2008-12-01

    We present aircraft measurements of dust aerosol during the Dust and Biomass-burning Experiment (DABEX), a project affiliated with the African Monsoon Multidisciplinary Analysis. DABEX took place between 13 January and 3 February 2006 in Sahelian west Africa, with the aircraft based at Niamey, Niger. The data set is augmented with Aerosol Robotic Network (AERONET) data. A mineral dust layer below 1-2 km (sourced from the north) and an overlying biomass burning (BB) layer (sourced from anthropogenic fires to the south) was observed on all days, although variability was observed in both layers. There is evidence of ozone loss within the dust, but with CO levels between 140 and 170 ppbv some history of combustion has occurred. Size distribution of the dust is compared with that of the BB aerosol and with dust measured near Senegal, during the Dust Outflow and Deposition to the Ocean (DODO-1) experiment. For accurate representation of the optical properties, five log-normals to the size distribution across sizes 0.05-5 μm are required, although two log-normals are adequate. The single scattering albedo was almost purely scattering, with values of 0.99 ± 0.01. During the strongest dust events the dust contribution to the column optical depth was 75-80%, compared to a DABEX mean of 50%. The aircraft-derived optical depth varied between 0.19 and 1.07, with the dust-only contribution between 0.07 and 0.81. AERONET optical depth trends are in good agreement with aircraft during DABEX, albeit with a bias to higher aircraft values. Retrieved AERONET aerosol size distributions show variable agreement with the aircraft. Differences between Versions 1 and 2 of the AERONET algorithm are highlighted.

  7. Development towards a global operational aerosol consensus: basic climatological characteristics of the International Cooperative for Aerosol Prediction Multi-Model Ensemble (ICAP-MME)

    NASA Astrophysics Data System (ADS)

    Sessions, W. R.; Reid, J. S.; Benedetti, A.; Colarco, P. R.; da Silva, A.; Lu, S.; Sekiyama, T.; Tanaka, T. Y.; Baldasano, J. M.; Basart, S.; Brooks, M. E.; Eck, T. F.; Iredell, M.; Hansen, J. A.; Jorba, O. C.; Juang, H.-M. H.; Lynch, P.; Morcrette, J.-J.; Moorthi, S.; Mulcahy, J.; Pradhan, Y.; Razinger, M.; Sampson, C. B.; Wang, J.; Westphal, D. L.

    2015-01-01

    Here we present the first steps in developing a global multi-model aerosol forecasting ensemble intended for eventual operational and basic research use. Drawing from members of the International Cooperative for Aerosol Prediction (ICAP) latest generation of quasi-operational aerosol models, 5-day aerosol optical thickness (AOT) forecasts are analyzed for December 2011 through November 2012 from four institutions: European Centre for Medium-Range Weather Forecasts (ECMWF), Japan Meteorological Agency (JMA), NASA Goddard Space Flight Center (GSFC), and Naval Research Lab/Fleet Numerical Meteorology and Oceanography Center (NRL/FNMOC). For dust, we also include the National Oceanic and Atmospheric Administration-National Geospatial Advisory Committee (NOAA NGAC) product in our analysis. The Barcelona Supercomputing Centre and UK Met Office dust products have also recently become members of ICAP, but have insufficient data to be included in this analysis period. A simple consensus ensemble of member and mean AOT fields for modal species (e.g., fine and coarse mode, and a separate dust ensemble) is used to create the ICAP Multi-Model Ensemble (ICAP-MME). The ICAP-MME is run daily at 00:00 UTC for 6-hourly forecasts out to 120 h. Basing metrics on comparisons to 21 regionally representative Aerosol Robotic Network (AERONET) sites, all models generally captured the basic aerosol features of the globe. However, there is an overall AOT low bias among models, particularly for high AOT events. Biomass burning regions have the most diversity in seasonal average AOT. The Southern Ocean, though low in AOT, nevertheless also has high diversity. With regard to root mean square error (RMSE), as expected the ICAP-MME placed first over all models worldwide, and was typically first or second in ranking against all models at individual sites. These results are encouraging; furthermore, as more global operational aerosol models come online, we expect their inclusion in a robust

  8. Aerosolization characteristics of dry powder inhaler formulations for the excipient enhanced growth (EEG) application: effect of spray drying process conditions on aerosol performance.

    PubMed

    Son, Yoen-Ju; Worth Longest, P; Hindle, Michael

    2013-02-25

    The aim of this study was to develop a spray dried submicrometer powder formulation suitable for the excipient enhanced growth (EEG) application. Combination particles were prepared using the Buchi Nano spray dryer B-90. A number of spray drying and formulation variables were investigated with the aims of producing dry powder formulations that were readily dispersed upon aerosolization and maximizing the fraction of submicrometer particles. Albuterol sulfate, mannitol, L-leucine, and poloxamer 188 were selected as a model drug, hygroscopic excipient, dispersibility enhancer and surfactant, respectively. Formulations were assessed by scanning electron microscopy and aerosol performance following aerosolization using an Aerolizer dry powder inhaler (DPI). In vitro drug deposition was studied using a realistic mouth-throat (MT) model. Based on the in vitro aerosolization results, the best performing submicrometer powder formulation consisted of albuterol sulfate, mannitol, L-leucine and poloxamer 188 in a ratio of 30:48:20:2, containing 0.5% solids in a water:ethanol (80:20%, v/v) solution which was spray dried at 70 °C. The submicrometer particle fraction (FPF(1 μm/ED)) of this final formulation was 28.3% with more than 80% of the capsule contents being emitted during aerosolization. This formulation also showed 4.1% MT deposition. The developed combination formulation delivered a powder aerosol developed for the EEG application with high dispersion efficiency and low MT deposition from a convenient DPI device platform. PMID:23313343

  9. Aerosolization Characteristics of Dry Powder Inhaler Formulations for the Excipient Enhanced Growth (EEG) Application: Effect of Spray Drying Process Conditions on Aerosol Performance

    PubMed Central

    Son, Yoen-Ju; Longest, P. Worth; Hindle, Michael

    2013-01-01

    The aim of this study was to develop a spray dried submicrometer powder formulation suitable for the excipient enhanced growth (EEG) application. Combination particles were prepared using the Buchi Nano spray dryer B-90. A number of spray drying and formulation variables were investigated with the aims of producing dry powder formulations that were readily dispersed upon aerosolization and maximizing the fraction of submicrometer particles. Albuterol sulfate, mannitol, L-leucine, and poloxamer 188 were selected as a model drug, hygroscopic excipient, dispersibility enhancer and surfactant, respectively. Formulations were assessed by scanning electron microscopy and aerosol performance following aerosolization using an Aerolizer® dry powder inhaler (DPI). In vitro drug deposition was studied using a realistic mouth-throat (MT) model. Based on the in vitro aerosolization results, the best performing submicrometer powder formulation consisted of albuterol sulfate, mannitol, L-leucine and poloxamer 188 in a ratio of 30:48:20:2, containing 0.5% solids in a water:ethanol (80:20% v/v) solution which was spray dried at 70 °C. The submicrometer particle fraction (FPF1μm/ED) of this final formulation was 28.3% with more than 80% of the capsule contents being emitted during aerosolization. This formulation also showed 4.1% MT deposition. The developed combination formulation delivered a powder aerosol developed for the EEG application with high dispersion efficiency and low MT deposition from a convenient DPI device platform. PMID:23313343

  10. Overview of the Stratospheric Aerosol and Gas Experiment II water vapor observations - Method, validation, and data characteristics

    NASA Technical Reports Server (NTRS)

    Rind, D.; Chiou, E.-W.; Chu, W.; Oltmans, S.; Lerner, J.; Larsen, J.; Mccormick, M. P.; Mcmaster, L.

    1993-01-01

    Results are presented of water vapor observations in the troposphere and stratosphere performed by the Stratospheric Aerosol and Gas Experiment II solar occultation instrument, and the analysis procedure, the instrument errors, and data characteristics are discussed. The results are compared with correlative in situ measurements and other satellite data. The features of the data set collected between 1985 and 1989 include an increase in middle- and upper-tropospheric water vapor during northern hemisphere summer and autumn; minimum water vapor values of 2.5-3 ppmv in the tropical lower stratosphere; slowly increasing water vapor values with altitude in the stratosphere, reaching 5-6 ppmv or greater near the stratopause; extratropical values with minimum profile amounts occurring above the conventionally defined tropopause; and higher extratropical than tropical water vapor values throughout the stratosphere except in locations of possible polar stratospheric clouds.

  11. Characteristics of size-segregated carbonaceous aerosols in the Beijing-Tianjin-Hebei region.

    PubMed

    Guo, Yuhong

    2016-07-01

    Mass concentrations of organic carbon (OC) and elemental carbon (EC) in size-resolved aerosols were investigated at four sites (three cities and one country) in the Beijing-Tianjin-Hebei region from September 2009 to August 2011. The size distributions of OC and EC presented large evolutions among rural and urban sites, and among four seasons, with highest peaks of OC and EC in fine mode in urban areas during winter. Geometric mean diameters (GMDs) of OC and EC in fine particles at urban sites during winter were lower than those at rural site mainly due to effects of fine particle coagulation and organic compound repartitioning. Fossil fuel emissions were a dominant source of OC and EC in urban areas, while biomass burning was a major source of OC and EC at rural site. Trajectory clustering and CWT analysis showed that regional transport was an important contributor to OC and EC in Beijing. PMID:27040539

  12. AeroCom INSITU Project: Comparing modeled and measured aerosol optical properties

    NASA Astrophysics Data System (ADS)

    Andrews, Elisabeth; Schmeisser, Lauren; Schulz, Michael; Fiebig, Markus; Ogren, John; Bian, Huisheng; Chin, Mian; Easter, Richard; Ghan, Steve; Kokkola, Harri; Laakso, Anton; Myhre, Gunnar; Randles, Cynthia; da Silva, Arlindo; Stier, Phillip; Skeie, Ragnehild; Takemura, Toshihiko; van Noije, Twan; Zhang, Kai

    2016-04-01

    AeroCom, an open international collaboration of scientists seeking to improve global aerosol models, recently initiated a project comparing model output to in-situ, surface-based measurements of aerosol optical properties. The model/measurement comparison project, called INSITU, aims to evaluate the performance of a suite of AeroCom aerosol models with site-specific observational data in order to inform iterative improvements to model aerosol modules. Surface in-situ data has the unique property of being traceable to physical standards, which is an asset in accomplishing the overall goal of bettering the accuracy of aerosols processes and the predicative capability of global climate models. Here we compare dry, in-situ aerosol scattering and absorption data from ~75 surface, in-situ sites from various global aerosol networks (including NOAA, EUSAAR/ACTRIS and GAW) with a simulated optical properties from a suite of models participating in the AeroCom project. We report how well models reproduce aerosol climatologies for a variety of time scales, aerosol characteristics and behaviors (e.g., aerosol persistence and the systematic relationships between aerosol optical properties), and aerosol trends. Though INSITU is a multi-year endeavor, preliminary phases of the analysis suggest substantial model biases in absorption and scattering coefficients compared to surface measurements, though the sign and magnitude of the bias varies with location. Spatial patterns in the biases highlight model weaknesses, e.g., the inability of models to properly simulate aerosol characteristics at sites with complex topography. Additionally, differences in modeled and measured systematic variability of aerosol optical properties suggest that some models are not accurately capturing specific aerosol behaviors, for example, the tendency of in-situ single scattering albedo to decrease with decreasing aerosol extinction coefficient. The endgoal of the INSITU project is to identify specific

  13. Evaluation of IASI derived dust aerosols characteristics over the tropical belt

    NASA Astrophysics Data System (ADS)

    Capelle, Virginie; Chédin, Alain; Pondrom, Marc; Siméon, Mathilde; Tsamalis, Christophe; Pierangelo, Clémence; Armante, Raymond; Crevoisier, Cyril; Crépeau, Laurent; Scott, Noëlle

    2014-05-01

    IASI-derived monthly mean infrared (10 µm) dust aerosol optical depth (AOD) and altitude are evaluated against ground based AERONET measurements of the 500 nm coarse mode AOD and CALIOP measurements of the altitude at 38 AERONET sites (land and sea) within the tropical belt (30°N-30°S). The period covered extends from July 2007 to December 2013. The evaluation goes through the analysis of Taylor diagrams and box and whiskers plots, separating situations over sea and over land. Concerning AOD, the overall correlation for the sites over sea comes to 0.88 for 713 items (IASI and AERONET monthly mean bins). The overall normalized standard deviation is of 0.96. Over land, essentially desert, correlation is of 0.74 for 582 items and the normalized standard deviation is of 0.87. This slight but significant degradation over land most probably results from the greater complexity of the surface (heterogeneity, elevation) and, to a lesser extent, to the episodic presence of dust within the boundary layer (particularly for sites close to active sources) to which IASI, as any thermal infrared sounder, is poorly sensitive contrary to AERONET. Concerning altitude over sea, correlation is of 0.78 for 925 items and the normalized standard deviation is of 1.03. Results over land, essentially over deserts, are not satisfactory for a majority of sites. Extension of the approach to extra-tropical sites, in particular the Mediterranean basin, is in progress and preliminary results will be shown. We conclude that the present results demonstrate the usefulness of IASI data as an additional constraint to a better knowledge of the impact of aerosols on the climate system.

  14. Characteristics of aerosol pollution during heavy haze events in Suzhou, China

    NASA Astrophysics Data System (ADS)

    Tian, Mi; Wang, Huanbo; Chen, Yang; Yang, Fumo; Zhang, Xiaohua; Zou, Qiang; Zhang, Renquan; Ma, Yongliang; He, Kebin

    2016-06-01

    Extremely severe haze weather events occurred in many cities in China, especially in the east part of the country, in January 2013. Comprehensive measurements including hourly concentrations of PM2.5 and its major chemical components (water-soluble inorganic ions, organic carbon (OC), and elemental carbon (EC)) and related gas-phase precursors were conducted via an online monitoring system in Suzhou, a medium-sized city in Jiangsu province, just east of Shanghai. PM2.5 (particulate matter with an aerodynamic diameter of 2.5 µm or less) frequently exceeded 150 µg m-3 on hazy days, with the maximum reaching 324 µg m-3 on 14 January 2013. Unfavorable weather conditions (high relative humidity (RH), and low rainfall, wind speed, and atmospheric pressure) were conducive to haze formation. High concentrations of secondary aerosol species (including SO42-, NO3-, NH4+, and SOC) and gaseous precursors were observed during the first two haze events, while elevated primary carbonaceous species emissions were found during the third haze period, pointing to different haze formation mechanisms. Organic matter (OM), (NH4)2SO4, and NH4NO3 were found to be the major contributors to visibility impairment. High concentrations of sulfate and nitrate might be explained by homogeneous gas-phase reactions under low RH conditions and by heterogeneous processes under relatively high RH conditions. Analysis of air mass trajectory clustering and potential source contribution function showed that aerosol pollution in the studied areas was mainly caused by local activities and surrounding sources transported from nearby cities.

  15. Observations and Inferred Physical Characteristics of Compact Intracloud Discharges

    SciTech Connect

    Argo, P.E.; Eack, K.B.; Holden, D.N.; Massey, R.S.; Shao, X.; Smith, D.A.; Wiens, K.C.

    1999-02-01

    Compact intracloud discharges (CIDS) represent a distinct class of electrical discharges that occur within intense regions of thunderstorms. They are singular discharges that produce brief (typically 3 µs in duration) broadband RF emissions that are 20 to 30 dB more powerful than radiation from all other recorded lightning processes in the HF and VHF radio spectrum. Far field electric field change recordings of CIDS consist of a single, large-amplitude bipolar pulse that begins to rise during the RF-producing phase of the CID and typically lasts for 20 µs. During the summer of 1998 we operated a 4-station array of electric field change meters in New Mexico to support FORTE satellite observations of transient RF and optical sources and to learn more about the phenomenology and physical characteristics of CIDS. Over 800 CIDS were detected and located during the campaign. The events were identified on the basis of their unique field change waveforms. CID source heights determined using the relative delays of ionospherically reflected source emissions were typically between 4 and 11 km above ground level. Events of both positive and negative polarity were observed with events' of initially- negative polarity (indicative of discharges occurring between underlying positive and overlying negative charge) occurring at slightly higher altitudes. Within CID field change waveforms the CID pulse was often followed within a few ms by one or more smaller-amplitude pulses. We associate these subsequent pulses with the initial activity of a "normal" intracloud flash, the inference being that some fraction of the time, a CID initiates an intracloud lightning flash.

  16. Anthropometric Characteristics and Physical Performance of Colombian Elite Male Wrestlers

    PubMed Central

    Ramirez-Velez, Robinson; Argothyd, Rodrigo; Meneses-Echavez, Jose Francisco; Beatriz Sanchez-Puccini, Maria; Lopez-Alban, Carlos Alejandro; Cohen, Daniel Dylan

    2014-01-01

    Background: Wrestling was an important part of the ancient Olympic Games and is still one of the most popular events of the modern Olympic Games. Studies indicate that general physiologic profile of successful wrestlers is high anaerobic power and capacity, muscular strength, above average aerobic power, exceptional flexibility, fat free mass, and a mesomorphic somatotype. Objectives: The objective of the present study was to evaluate anthropometric characteristics and physical performance of elite male wrestlers. Patients and Methods: The Colombian Wrestling Team was evaluated while in preparation for the Olympic Games (n = 21; age, 27.9 ± 6.7 years). Athletes were tested on anthropometric and fitness parameters: body composition, somatotype distribution according to Heath-Carter, aerobic capacity, vertical jump, and anaerobic power. Results: The evaluations showed a mean body fat percentage of 13.6% ± 3.0% (95% CI, 12.2%-15%), muscle mass of 46.4% ± 2.2% (95% CI, 45.4%-47.4%), Ponderal index of 41.0 ± 1.8 (95% CI, 40.2-41.8), body adiposity index (BAI) 25.1 ± 3.6 (95% CI, 23.5-26.8), and somatotype distribution mesomorphic-ectomorph (5.3-1.6-3.8). Mean aerobic capacity was 45.9 ± 6.6 mL/kg/min (95% CI, 42.8-48.9), vertical jump was 36.4 ± 6.6 cm (95% CI, 11.8-16.6), and anaerobic power was 92.6 ± 19.5 kg/s (95% CI, 83.7-101.5). Conclusions: These results provided a profile of elite wrestlers that could be used as training targets for developing athletes. The results may also provide information for training and tactical planning. PMID:25741411

  17. Physical characteristics of five clinical systems for digital mammography

    SciTech Connect

    Lazzari, B.; Belli, G.; Gori, C.; Rosselli Del Turco, M.

    2007-07-15

    The purpose of this study was to evaluate and compare the physical characteristics of five clinical systems for digital mammography (GE Senographe 2000D, Lorad Selenia M-IV, Fischer Senoscan, Agfa DM 1000, and IMS Giotto) currently in clinical use. The basic performances of the mammography systems tested were assessed on the basis of response curve, modulation transfer function (MTF), noise power spectrum, noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) in an experimental setting closely resembling the clinical one. As expected, all the full field digital mammography systems show a linear response curve over a dynamic range from 3.5 to 500 {mu}Gy (0.998

  18. Physical characteristics of five clinical systems for digital mammography.

    PubMed

    Lazzari, B; Belli, G; Gori, C; Rosselli Del Turco, M

    2007-07-01

    The purpose of this study was to evaluate and compare the physical characteristics of five clinical systems for digital mammography (GE Senographe 2000D, Lorad Selenia M-IV, Fischer Senoscan, Agfa DM 1000, and IMS Giotto) currently in clinical use. The basic performances of the mammography systems tested were assessed on the basis of response curve, modulation transfer function (MTF), noise power spectrum, noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) in an experimental setting closely resembling the clinical one. As expected, all the full field digital mammography systems show a linear response curve over a dynamic range from 3.5 to 500 microGy (0.998

  19. Photoelectrochemical and physical properties of tungsten trioxide films obtained by aerosol pyrolysis

    SciTech Connect

    Sadale, S.B.; Chaqour, S.M.; Gorochov, O.; Neumann-Spallart, M.

    2008-06-03

    Aerosol pyrolysis (AP) was used for preparing semiconducting films of tungsten trioxide using peroxotungstic acid as a precursor. The films were characterized by SEM, XRD, and by their photoelectrochemical response. Porous, polycrystalline (monoclinic) films of thickness up to 3 {mu}m were prepared. An incident photon to current efficiency (IPCE) of 0.55 at 365 nm was obtained for films of 1 {mu}m thickness on conducting F:SnO{sub 2}/glass substrates under depletion conditions, in junctions with aqueous electrolytes. The spectral (photocurrent) response extended into the visible region (up to 470 nm) which is of importance for solar applications like photocatalysis.

  20. Thoron concentration, aerosol characteristics of 212Pb and estimation of equivalent dose

    NASA Astrophysics Data System (ADS)

    Mohery, M.; Abdallah, A. M.; Kelany, Adel M.; Yaghmour, S. J.

    2014-08-01

    The thoron gas (220Rn) activity concentration as well as activity size distribution of unattached and attached 212Pb to aerosol particles was measured in the open air of Jeddah City, Kingdom of Saudi Arabia. An electroprecipitation method was applied for measuring the 220Rn concentration. A mean activity concentration of 220Rn was determined to be 1.80±0.47 Bq m-3. The unattached activities of 212Pb were collected using the wire screen diffusion battery technique while a low-pressure cascade impactor collected the attached activities. The mean activity median thermodynamic diameter (AMTD) of unattached 212Pb was determined to be 1.32 nm with a relative mean geometric standard deviation (σg) of 1.45. A mean concentration of unattached activity of 212Pb was found to be 9.48±1.12 mBq m-3. A mean unattached fraction (fp) of 0.028±0.002 was obtained at a mean aerosol particle concentration of 29×103 cm-3. Sometimes, the fp values were less than the detection limit of 0.009. A mean activity median aerodynamic diameter (AMAD) of the accumulation mode of attached 212Pb was determined to be 352 nm with a mean (σg) of 2.6. The mean value of specific air activity concentration of 212Pb associated with that mode was determined to be 310±12 mBq m-3. With a dosimetric model calculation (ICRP, 1994) the total and regional deposition fractions, total and regional equivalent doses could be evaluated considering the obtained parameters of the activity size distributions. At a total deposition fraction of about 97% of unattached activities the total equivalent dose to the human lung was determined to be 0.16 μSv while a total equivalent dose of 0.44 μSv was determined at a total deposition fraction of about 23% for the attached activities. It was found that an unattached fraction of fP≈3% yields to about 27% of the total equivalent dose.

  1. Temporal characteristics of inhalable mercury and arsenic aerosols in the urban atmosphere in southern Taiwan

    NASA Astrophysics Data System (ADS)

    Tsai, Ying I.; Kuo, Su-Ching; Lin, Yi-Hsuan

    Urban aerosol samples for PM 10 and PM 2.5 were collected during summer (August) and winter (December) 2000 in southern Taiwan (Tainan City) to demonstrate the temporal variations of Hg and As in particulate matter (PM). The mean mass concentrations with standard deviations were 80.0±26.8 μg m -3 for PM 10 and 50.6±16.6 μg m -3 for PM 2.5. The average PM 2.5/PM 10 mass ratio for the two periods combined was 63%, indicating that fine particles were a large portion of PM 10. Particulate samples of Hg and As were analyzed within 2 days following sampling and weighing, because of the highly volatile nature of PM Hg and As. The average Hg and As values in PM 10, PM 2.5 and PM 2.5-10 in summer were significantly lower than those in winter. PM 2.5 Hg constituted 0.34 to 5.8 ng m -3 and PM 2.5-10 Hg 0.05 to 3.1 ng m -3. PM 2.5 As constituted 1.09 to 9.51 ng m -3 and PM 2.5-10 As 0.18 to 4.14 ng m -3. In summer and winter PM 10, the Hg contents showed regular daily variation, with the higher values at daytime and lower values at nighttime, indicating conversion of gaseous Hg to the particulate phase by reaction with atmospheric oxidants under strong solar radiation during the daytime in both summer and winter. PM As behaved similar to Hg in the summer, but in the winter higher concentrations were observed during the nighttime than during the daytime, implying that the stable temperature inversion during winter nighttime caused the accumulation of PM As near the ground. In summer, SE-WSW winds carried As from an As-emitting fossil power plant to the sample area. In a similar vein, NE-WNW winter winds contributed to aerosol Hg, especially in PM 2.5, originating from a waste incinerator located NW of Tainan City.

  2. The characteristics of Beijing aerosol during two distinct episodes: impacts of biomass burning and fireworks.

    PubMed

    Cheng, Yuan; Engling, Guenter; He, Ke-bin; Duan, Feng-kui; Du, Zhen-yu; Ma, Yong-liang; Liang, Lin-lin; Lu, Zi-feng; Liu, Jiu-meng; Zheng, Mei; Weber, Rodney J

    2014-02-01

    The chemical composition of Beijing aerosol was measured during summer and winter. Two distinct episodes were identified. Water-soluble potassium (K(+)) increased significantly during the firework episode in winter with an episode to non-episode ratio of 4.97, whereas the biomass burning (BB) episode in summer was characterized by high episode to non-episode ratios of levoglucosan (6.38) and K(+) (6.90). The BB and firework episodes had only a minor influence on the water-soluble OC (organic carbon) to OC ratio. Based on separate investigations of episode and non-episode periods, it was found that: (i) sulfate correlated strongly with both relative humidity and nitrate during the typical winter period presumably indicating the importance of the aqueous-phase oxidation of sulfur dioxide by nitrogen dioxide, (ii) oxalate and WSOC during both winter and summer in Beijing were mainly due to secondary formation, and (iii) high humidity can significantly enhance the formation potential of WSOC in winter. PMID:24275313

  3. Thermal characteristics and mass absorption efficiency of carbonaceous aerosol measured during a post-harvest burning period

    NASA Astrophysics Data System (ADS)

    Batmunkh, T.; Kim, Y. J.; Cayetano, M. G.; Lee, K.; Kim, K.; Park, K.

    2012-12-01

    In order to better understand the characteristics of carbonaceous aerosol time-resolved OC, EC, and BC were measured by a Sunset OC/EC analyzer and an Aethalometer, respectively, during a post-harvest burning period from November 22 to December 20, 2011 at a sub-urban site in Gwangju, Korea. OC and EC were analyzed by the thermal-optical transmittance (TOT) method with NIOSH temperature protocol. The spectral light absorption coefficient (babs) was determined based on the Aethalometer data. Overall average OC and EC concentrations were found to be 5.0±2.4 ugC/ m3 and 1.5±0.9 ugC/ m3, respectively for the sampling period. On average, babs at seven Aethalometer wavelengths was found to be 38.4±27.8 Mm-1, 24.3±17.8 Mm-1, 20.8±15.4 Mm-1, 17.9±13.3 Mm-1, 14.9±11.1 Mm-1, 9.9±7.4 Mm-1, and 8.8±6.6 Mm-1 at 370 nm, 470 nm, 520 nm, 590 nm, 660 nm, 880 nm, and 950 nm, respectively. Clear diurnal variations with morning (7:00 AM~9:00 AM) and evening (7:00 PM~11:00 PM) peaks were observed for OC, EC, and babs mostly due to local burning activities. Based on the 4-day back-trajectory analyses conducted using the HYSPLIT model. Event cases were classified into four categories, based on the 4-day air mass back trajectories, as Clean(C), Stagnant(ST), Continental(CC), and Local Burning(LB) events. In order to better investigate the characteristics of atmospheric carbonaceous aerosol, thermal evolution patterns of carbonaceous aerosol measured by the Sunset analyzer were characterized as OC1, OC2, and EC, which were detected in temperature steps of 600 C, 840 C in an non-oxidizing atmosphere, and 870 C in an oxidizing atmosphere, respectively. High ratio of OC2/OC1; 1.39~1.41 was observed in the evening 9:00~11:00 PM due to local burning event. Concentration of OC2 was higher up to 1.4 times than that of OC1 for the LB cases, showing that higher molecular weight fraction of organic aerosol was dominant for the time. As expected, higher correlation was found between EC and

  4. Insights into characteristics, sources, and evolution of submicron aerosols during harvest seasons in the Yangtze River delta region, China

    NASA Astrophysics Data System (ADS)

    Zhang, Y. J.; Tang, L. L.; Wang, Z.; Yu, H. X.; Sun, Y. L.; Liu, D.; Qin, W.; Canonaco, F.; Prévôt, A. S. H.; Zhang, H. L.; Zhou, H. C.

    2015-02-01

    Atmospheric submicron particulate matter (PM1) is one of the most significant pollution components in China. Despite its current popularity in the studies of aerosol chemistry, the characteristics, sources and evolution of atmospheric PM1 species are still poorly understood in China, particularly for the two harvest seasons, namely, the summer wheat harvest and autumn rice harvest. An Aerodyne Aerosol Chemical Speciation Monitor (ACSM) was deployed for online monitoring of PM1 components during summer and autumn harvest seasons in urban Nanjing, in the Yangtze River delta (YRD) region of China. PM1 components were shown to be dominated by organic aerosol (OA, 39 and 41%) and nitrate (23 and 20%) during the harvest seasons (the summer and autumn harvest). Positive matrix factorization (PMF) analysis of the ACSM OA mass spectra resolved four OA factors: hydrocarbon-like mixed with cooking-related OA (HOA + COA), fresh biomass-burning OA (BBOA), oxidized biomass-burning-influenced OA (OOA-BB), and highly oxidized OA (OOA); in particular the oxidized BBOA contributes ~80% of the total BBOA loadings. Both fresh and oxidized BBOA exhibited apparent diurnal cycles with peak concentration at night, when the high ambient relative humidity and low temperature facilitated the partitioning of semi-volatile organic species into the particle phase. The fresh BBOA concentrations for the harvests are estimated as BBOA = 15.1 × (m/z 60-0.26% × OA), where m/z (mass-to-charge ratio) 60 is a marker for levoglucosan-like species. The (BBOA + OOA-BB)/ΔCO, (ΔCO is the CO minus background CO), decreases as a function of f44 (fraction of m/z 44 in OA signal), which might indicate that BBOA was oxidized to less volatile OOA, e.g., more aged and low volatility OOA (LV-OOA) during the aging process. Analysis of air mass back trajectories indicates that the high BB pollutant concentrations are linked to the air masses from the western (summer harvest) and southern (autumn harvest) areas.

  5. Vegetation damage as a proxy for physical characteristics of PDCs

    NASA Astrophysics Data System (ADS)

    Pollock, N.; Harpp, K. S.; Geist, D.; Dufek, J.; Mothes, P. A.

    2010-12-01

    As one of Ecuador’s most active volcanoes, Tungurahua poses a constant threat to the surrounding area. Pyroclastic density currents (PDCs) are the most significant hazard owing to their mobility and the difficulty of measuring their physical properties during emplacement. We present a study of the deposits from the 2006 eruptions at Tungurahua, which produced PDCs that descended multiple valleys, destroying over a dozen towns and claiming at least six lives. There were two main periods of activity during the summer of 2006: July 14-16, which produced 20 PDC events, and August 16-17, when 32 PDCs descended the flanks in only eight hours. The deposits consist of 3 main facies: scoria-bomb accumulations, ash-rich deposits, and ash cloud surges surrounding the dense flows. The currents were generated by boiling-over activity, and the deposits are characterized by concentrations of juvenile bread crust bombs up to 2 m in diameter predominately in levees and flow snouts. Two of the largest deposits are in Juive Grande and Cusua valleys, which experienced 12 and 26 events, respectively. Despite the petrologic and granulometric similarities of the two valley deposits, they have markedly different emplacement characteristics as recorded by damage to vegetation. In Juive Grande, wood (up to 8 cm diameter) was charred to its center at multiple locations. At Cusua, vegetation is charred only within the outermost few millimeters and has no interior damage; no completely charred wood was found in Cusua. To address this paradox, damaged vegetation was collected from both deposits to examine emplacement temperature, velocity, and particle concentration of the flows using laboratory experiments. Methods include charring wood in lab using materials from PDCs at Tungurahua, abrasion of wood with ash and lapilli, examination of cellular damage to wood using the SEM, and vitrinite reflectance measurements. Charring experiments conducted at varying temperatures with different wood

  6. Description of the Sun as a Star: General Physical Characteristics

    NASA Technical Reports Server (NTRS)

    Kucera, Theresa; Crannell, Carol Jo

    2000-01-01

    Numerical parameters characterizing the size and energy output of the sun are presented. These values are the standard yardstick by which other stars are measured. The large number of significant digits tabulated here serve mainly to illustrate the precision to which these parameters are known. Also listed are parameters characterizing the earth's orbit around the sun and the intensity of the sun's radiation at the mean orbital distance. The appearance of the sun depends critically on how it is observed. Each type of radiation observed carries specific information about the physical processes at work on the sun. Special types of instruments reveal aspects otherwise invisible. Coronagraphs reveal the dimmer outer regions of the sun's atmosphere otherwise visible only during total solar eclipses. Spectroscopy can reveal motions, magnetic field strengths, temperatures and densities. In situ measurements have revealed the characteristics of the solar wind and extended our knowledge of the solar magnetic field both near the earth and beyond the orbits of the planets. As an example, the sun's disk observed almost simultaneously in six different wavelengths of light is shown. In visible light we can see the white disk of the sun with the dark spots known as sunspots. By analyzing the spectral lines produced by the sun we can measure the strength of the sun's magnetic field at its surface, producing a magnetogram. This magnetogram reveals that the sunspots are regions of intense magnetic field. Further images of the sun reveal that the sunspot regions are just the bases of systems of hot loops which emit radio-waves, ultraviolet light and X-rays. The sun imaged in a spectral line of hydrogen known as "H alpha" is shown. In this line we also see the long dark "filaments". These filaments form in long channels between areas of opposing magnetic field. Such channels can be seen in the ultraviolet image. Data concerning the sun are obtained with many different kinds of

  7. The dynamical core, physical parameterizations, and basic simulation characteristics of the atmospheric component AM3 of the GFDL global coupled model CM3

    USGS Publications Warehouse

    Donner, L.J.; Wyman, B.L.; Hemler, R.S.; Horowitz, L.W.; Ming, Y.; Zhao, M.; Golaz, J.-C.; Ginoux, P.; Lin, S.-J.; Schwarzkopf, M.D.; Austin, J.; Alaka, G.; Cooke, W.F.; Delworth, T.L.; Freidenreich, S.M.; Gordon, C.T.; Griffies, S.M.; Held, I.M.; Hurlin, W.J.; Klein, S.A.; Knutson, T.R.; Langenhorst, A.R.; Lee, H.-C.; Lin, Y.; Magi, B.I.; Malyshev, S.L.; Milly, P.C.D.; Naik, V.; Nath, M.J.; Pincus, R.; Ploshay, J.J.; Ramaswamy, V.; Seman, C.J.; Shevliakova, E.; Sirutis, J.J.; Stern, W.F.; Stouffer, R.J.; Wilson, R.J.; Winton, M.; Wittenberg, A.T.; Zeng, F.

    2011-01-01

    The Geophysical Fluid Dynamics Laboratory (GFDL) has developed a coupled general circulation model (CM3) for the atmosphere, oceans, land, and sea ice. The goal of CM3 is to address emerging issues in climate change, including aerosol-cloud interactions, chemistry-climate interactions, and coupling between the troposphere and stratosphere. The model is also designed to serve as the physical system component of earth system models and models for decadal prediction in the near-term future-for example, through improved simulations in tropical land precipitation relative to earlier-generation GFDL models. This paper describes the dynamical core, physical parameterizations, and basic simulation characteristics of the atmospheric component (AM3) of this model. Relative to GFDL AM2, AM3 includes new treatments of deep and shallow cumulus convection, cloud droplet activation by aerosols, subgrid variability of stratiform vertical velocities for droplet activation, and atmospheric chemistry driven by emissions with advective, convective, and turbulent transport. AM3 employs a cubed-sphere implementation of a finite-volume dynamical core and is coupled to LM3, a new land model with ecosystem dynamics and hydrology. Its horizontal resolution is approximately 200 km, and its vertical resolution ranges approximately from 70 m near the earth's surface to 1 to 1.5 km near the tropopause and 3 to 4 km in much of the stratosphere. Most basic circulation features in AM3 are simulated as realistically, or more so, as in AM2. In particular, dry biases have been reduced over South America. In coupled mode, the simulation of Arctic sea ice concentration has improved. AM3 aerosol optical depths, scattering properties, and surface clear-sky downward shortwave radiation are more realistic than in AM2. The simulation of marine stratocumulus decks remains problematic, as in AM2. The most intense 0.2% of precipitation rates occur less frequently in AM3 than observed. The last two decades of

  8. Influence of surface characteristics of modified glass beads as model carriers in dry powder inhalers (DPIs) on the aerosolization performance.

    PubMed

    Zellnitz, Sarah; Schroettner, Hartmuth; Urbanetz, Nora Anne

    2015-01-01

    The aim of this work is to investigate the effect of surface characteristics (surface roughness and specific surface area) of surface-modified glass beads as model carriers in dry powder inhalers (DPIs) on the aerosolization, and thus, the in vitro respirable fraction often referred to as fine particle fraction (FPF). By processing glass beads in a ball mill with different grinding materials (quartz and tungsten carbide) and varying grinding time (4 h and 8 h), and by plasma etching for 1 min, glass beads with different shades of surface roughness and increased surface area were prepared. Compared with untreated glass beads, the surface-modified rough glass beads show increased FPFs. The drug detachment from the modified glass beads is also more reproducible than from untreated glass beads indicated by lower standard deviations for the FPFs of the modified glass beads. Moreover, the FPF of the modified glass beads correlates with their surface characteristics. The higher the surface roughness and the higher the specific surface area of the glass beads the higher is the FPF. Thus, surface-modified glass beads make an ideal carrier for tailoring the performance of DPIs in the therapy of asthma and chronically obstructive pulmonary diseases. PMID:25632978

  9. Aerosols and environmental pollution

    NASA Astrophysics Data System (ADS)

    Colbeck, Ian; Lazaridis, Mihalis

    2010-02-01

    The number of publications on atmospheric aerosols has dramatically increased in recent years. This review, predominantly from a European perspective, summarizes the current state of knowledge of the role played by aerosols in environmental pollution and, in addition, highlights gaps in our current knowledge. Aerosol particles are ubiquitous in the Earth’s atmosphere and are central to many environmental issues; ranging from the Earth’s radiative budget to human health. Aerosol size distribution and chemical composition are crucial parameters that determine their dynamics in the atmosphere. Sources of aerosols are both anthropogenic and natural ranging from vehicular emissions to dust resuspension. Ambient concentrations of aerosols are elevated in urban areas with lower values at rural sites. A comprehensive understanding of aerosol ambient characteristics requires a combination of measurements and modeling tools. Legislation for ambient aerosols has been introduced at national and international levels aiming to protect human health and the environment.

  10. Characteristics of carbonaceous aerosol in PM 2.5: Pearl Delta River Region, China

    NASA Astrophysics Data System (ADS)

    Huang, H.; Ho, K. F.; Lee, S. C.; Tsang, P. K.; Ho, Steven Sai Hang; Zou, C. W.; Zou, S. C.; Cao, J. J.; Xu, H. M.

    2012-02-01

    Simultaneous measurements of atmospheric organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) were made at four sampling sites, namely Guangzhou (GZ), Zhaoqing (ZQ), PolyU Campus (PU) and Hok Tsui (HT), in the Pearl River Delta (PRD) region between 14 August 2006 and 28 August 2007. The highest concentrations of total carbon (TC) were found at the medium-scale roadside site (PU) and the lowest were found at the regional-scale site (HT). Among the four sampling sites, the average WSOC at ZQ showed the highest concentrations, while the lowest were seen at HT. OC and EC concentrations revealed spring/summer minima and autumn/winter maxima at all sites except PU, which had a consistently high EC concentration all over the year. The highest WSOC/OC ratio was found at ZQ with an average of 0.41, suggesting that the OC was more oxidized in the atmosphere of the semi-rural site. The lowest WSOC/OC was found at the roadside site of PU. Moreover, the WSOC/OC ratio increased in autumn, when the photochemical reactions are the most active in the PRD region. This can be attributed to aging and atmospheric processing of the organic compounds during their transportation, or to the formation of secondary organic aerosol (SOA). Average annual secondary organic carbon (SOC) concentrations in PM2.5 were estimated to be 2.2 and 3.5 μg m- 3 for GZ and ZQ, comprising 33.5% and 42.8% of the corresponding OC concentrations, respectively. The results indicate that SOC is significant in the PRD region, and its formation mostly occurs within the region.

  11. Aerosol black carbon characteristics over Central India: Temporal variation and its dependence on mixed layer height

    NASA Astrophysics Data System (ADS)

    Kompalli, Sobhan Kumar; Babu, S. Suresh; Moorthy, K. Krishna; Manoj, M. R.; Kumar, N. V. P. Kiran; Shaeb, K. Hareef Baba; Joshi, Ashok Kumar

    2014-10-01

    In a first of its kind study over the Indian region, concurrent and extensive measurements of black carbon (BC) concentration and atmospheric boundary layer parameters are used to quantify the role of atmospheric boundary layer in producing temporal changes in BC. During this study, 18 months (2011-12) data of continuous measurements of BC aerosols, made over a semi-urban location, Nagpur, in Central India are used along with concurrent measurements of vertical profiles of atmospheric thermodynamics, made using weekly ascents of GPS aided Radiosonde for a period of 1 year. From the balloon data, mixed layer heights and ventilation coefficients are estimated, and the monthly and seasonal changes in BC mass concentration are examined in the light of the boundary layer changes. Seasonally, the BC mass concentration was highest (~ 4573 ± 1293 ng m- 3) in winter (December-February), and lowest (~ 1588 ± 897 ng m- 3) in monsoon (June-September), while remained moderate (~ 3137 ± 1446 ng m- 3) in pre-monsoon (March-May), and post-monsoon (~ 3634 ± 813 ng m- 3) (October-November) seasons. During the dry seasons, when the rainfall is scanty or insignificantly small, the seasonal variations in BC concentrations have a strong inverse relationship with mixed layer height and ventilation coefficient. However, the lowest BC concentrations do not occur during the season when the mixed layer height (MLH) is highest or the ventilation coefficient is the highest; rather it occurs when the rainfall is strong (during summer monsoon season) and airmass changes to primarily of marine origin.

  12. Wintertime aerosol characteristics over the Indo-Gangetic Plain (IGP): Impacts of local boundary layer processes and long-range transport

    NASA Astrophysics Data System (ADS)

    Nair, Vijayakumar S.; Moorthy, K. Krishna; Alappattu, Denny P.; Kunhikrishnan, P. K.; George, Susan; Nair, Prabha R.; Babu, S. Suresh; Abish, B.; Satheesh, S. K.; Tripathi, Sachchida Nand; Niranjan, K.; Madhavan, B. L.; Srikant, V.; Dutt, C. B. S.; Badarinath, K. V. S.; Reddy, R. Ramakrishna

    2007-07-01

    The Indo-Gangetic Plain (IGP) encompasses a vast area, (accounting for ˜21% of the land area of India), which is densely populated (accommodating ˜40% of the Indian population). Highly growing economy and population over this region results in a wide range of anthropogenic activities. A large number of thermal power plants (most of them coal fed) are clustered along this region. Despite its importance, detailed investigation of aerosols over this region is sparse. During an intense field campaign of winter 2004, extensive aerosol and atmospheric boundary layer measurements were made from three locations: Kharagpur (KGP), Allahabad (ALB), and Kanpur (KNP), within the IGP. These data are used (1) to understand the regional features of aerosols and BC over the IGP and their interdependencies, (2) to compare it with features at locations lying at far away from the IGP where the conditions are totally different, (3) to delineate the effects of mesoscale processes associated with changes in the local atmospheric boundary layer (ABL), (4) to investigate the effects of long-range transport or moving weather phenomena in modulating the aerosol properties as well as the ABL characteristics, and (5) to examine the changes as the season changes over to spring and summer. Our investigations have revealed very high concentrations of aerosols along the IGP, the average mass concentrations (MT) of total aerosols being in the range 260 to 300 μg m-3 and BC mass concentrations (MB) in the range 20 to 30 μg m-3 (both ˜5 to 8 times higher than the values observed at off-IGP stations) during December 2004. Despite, BC constituted about 10% to the total aerosol mass concentration, a value quite comparable to those observed elsewhere over India for this season. The dynamics of the local atmospheric boundary layer (ABL) as well as changes in local emissions strongly influence the diurnal variations of MT and MB, both being inversely correlated with the mixed layer height (Zi) and the

  13. Physical and chemical characteristics of Mount St. Helens airborne debris

    NASA Technical Reports Server (NTRS)

    Sedlacek, W. A.; Heiken, G. H.; Mroz, E. J.; Gladney, E. S.; Perrin, D. R.; Leifer, R.; Fisenne, I.; Hinchliffe, L.; Chuan, R. L.

    1982-01-01

    Tephra and aerosols from the May 18, 1980 eruption of Mount St. Helens, Washington were sampled in the lower stratosphere with a WB-57F aircraft. The main body of the plume was intercepted over western Kansas on May 20, 48 hours after the eruption, at an altitude of 15.2 km. Concentrations on filter samples were 26 ng of SO4(-2) of air and 579 ng of ash/g of air. Angular glass pyroclasts ranged in size from 0.5 to 10 microns, with a mean grain of 2 microns. Samples collected at altitudes of 16.7 and 12.5 km had only traces of SO4(-2) and ash. A second flight was flown, 72 hours after the eruption, on May 21. From north Texas to central Wyoming, at an altitude of 15.2 km less than 0.5 to 38 ng of ash/g of air and 1.0 to 2.2 ng of SO4(-2)/g of air were sampled. At an altitude of 18.3 km, from central Wyoming to NW New Mexico, the plume density and character were variable.

  14. Family social characteristics related to physical growth of young children.

    PubMed Central

    Christiansen, N; Mora, J O; Herrera, M G

    1975-01-01

    Altogether 164 poor families who had children of normal and subnormal weight and height were studied in Bogota, Colombia. Physical growth was found to be positively associated with expenditure on food, sanitary conditions in the home, mother's age, birth interval between surviving children, level of parental newspaper reading, aspirations for children, and socioeconomic status. Physical growth was negatively associated with crowded living conditions and family size. Only mother's age, family size, spacing of births, and sanitary conditions were related to weight and height, independent of socioeconomic status. Food expenditure, crowding, parental newspaper reading, and aspirations for children all reflected the influence of socioeconomic status upon physical growth. The findings emphasized the importance of within-class social differences as they affect the physical growth of young children. PMID:1182354

  15. Physics and technical characteristics of ultrasonic sonar systems

    NASA Astrophysics Data System (ADS)

    Maclsaac, Dan; Hämäläinen, Ari

    2002-01-01

    Over the last 20 years, ultrasonic sonar technology has become more prevalent in teaching introductory mechanics laboratories. Hence, an awareness of the physics, measurement constraints, classroom limitations, and pedagogic practices underlying these systems is beneficial professional knowledge for introductory mechanics instructors. This article describes the physics behind these systems at length, discusses Polaroid system technical constraints and behaviors, and suggests solutions for common problematic classroom situations. Alternate classroom sonar systems and sonar-related curricula materials are also addressed.

  16. Microbial quality and physical-chemical characteristics of thermal springs.

    PubMed

    Fazlzadeh, Mehdi; Sadeghi, Hadi; Bagheri, Pari; Poureshg, Yusef; Rostami, Roohollah

    2016-04-01

    Microbial quality and physical-chemical properties of recreational spas were surveyed to investigate the health aspect of the spas' water. A total of 195 samples were collected from pools and springs of the spas in five sites from Ardebil Province of Iran. The effects of an independent factor defined as 'condition' and its component sub-factors (i.e., sampling point, location, and sampling date) on microbial quality and physical-chemical properties of the spas were studied by applying path analysis. The influence of physical-chemical properties on microbial quality was also considered. The percentage of samples exceeding the ISIRI (Swimming pool water microbiological specifications (vol 9412), Institute of Standards and Industrial Research of Iran, Tehran, 2007) limits for Staphylococcus (spp.) was up to 55.8 in the springs and 87.8 in the pools, 58.1 and 99.2 for HPC, 90.7 and 97.8 for total coliform and fecal coliform, and 9.3 and 34.4 for Pseudomonas aeruginosa, respectively. There were significant differences between the pools and springs for both physical-chemical properties and microbial quality. From the path analysis, sampling point was the most effective sub-factor of 'condition' on both the physical-chemical properties and microbial quality. Among the physical-chemical properties, water color had the most enhancing or additive influence on microbial pollution, while EC indicated a reducing or subtractive effect. PMID:26072426

  17. Characteristics of mineral aerosol deposited on the glaciers of Mt. Elbrus, Caucasus, Russia.

    NASA Astrophysics Data System (ADS)

    Kutuzov, Stanislav; Shahgedanova, Maria; Mikhalenko, Vladimir; Ginot, Patrick; Lavrentiev, Ivan; Popov, Gregory

    2014-05-01

    Records of mineral aerosol (desert dust) stored in glaciers provide data on frequency and intensity of deposition events, source regions and atmospheric pathways of mineral dust. We present and discuss a chronology of dust deposition events recorded in the shallow firn and ice cores extracted on the Western Plateau, Mt. Elbrus (5150 m a.s.l.), Caucasus Mountains, Russia and covering the period of 2009-2013. Particle size distribution and chemical analysis (major ions, trace elements) were peformed using Coulter Counter Multisizer III, Abacus particle counter, IC and ICPMS analysis. Sampling was performed using continuous flow analysis (CFA) system. Annual average dust flux (264 μg/cm2 a-1) and average mass concentration (1.7 mg/kg) over the period 2007-2013 were calculated for the first time for this region. A combination of satellite imagery (MSG SEVIRI), trajectory models (FLEXTA, HYSPLIT) and meteorological data were used to accurately date each of the dust layers observed in shallow cores and investigate provenance of the dust and its pathways. Desert dust originating from the Middle East and Sahara was deposited on the Caucasus glaciers 3-6 times a year. Although less frequent, Saharan events are characterized by considerably higher dust loads than the more frequent Middle Eastern events. The mass median diameter of dust particles ranged between 2 and 9 μm. The deposition of dust resulted in elevated concentrations of most ions, especially Ca2+, Mg2+, K+, and sulphates. Dust originated from or passing over the Middle East was characterised by the elevated concentrations of nitrates and ammonia. This may be related to dust emissions from agricultural fields which, if abandoned due to droughts, become important sources of dust. By contrast, samples of the Saharan dust originated from natural sources showed lower concentrations of ammonium. The mean values of crustal enrichment factors for the measured trace elements including metals were calculated. Overall

  18. Characteristics of carbonaceous aerosols at a pair of suburban and downtown sites in Nanjing, China

    NASA Astrophysics Data System (ADS)

    Cui, H.; Zhang, J.; Zhao, Y.

    2014-12-01

    Carbonaceous species in PM2.5 were measured in three seasons (except winter) in downtown and around a year in suburban in Nanjing. In particular, the OC and EC concentrations were continuously measured with 1-h interval at both sites. The mean concentrations of PM2.5, OC, EC were 85.9 μg/m3, 10.4 μg/m3, 4.2 μg/m3 and 63.4 μg/m3, 8.1 μg/m3, 5.3μg/m3 for downtown and suburban respectively. At the suburban site, compared to the lowest average concentration in spring, the relatively higher concentration of carbonaceous aerosol in summer was caused by biomass-burning activities. Significant increasing peaks of OC (up to 122.9 ug/m3) and EC (up to 35.8 ug/m3) in suburban were recorded in the June 10th night, and it is indicated using back trajectory that the air mass came through nearby agriculture areas. On the other hand, the OC and EC concentrations during the 2nd AYG (Asian Youth Games, Aug 16th - 24th in 2013) compared to that in rest days in August reduced by 21% and 10%, respectively, attributing to the effective control measures on reduction of industrial point sources, temporary control of motor vehicle and fugitive dusts. Rations of OC/EC in suburban were much lower than that in downtown. This might be due to the fact that the sampling point in suburban is quite close (in 400 meters) to a main highway. Both OC and EC concentrations in suburban were higher in nighttime than daytime, except OC in summer, indicating the existence of strong SOC and supported by high OC/EC and O3 at noon. The annual average SOC estimated by EC-tracer methods occupied 34.5% and 36.7% of the total OC for the downtown and suburban areas, respectively. OC/EC correlations in suburban were much weaker than those from downtown areas, which shows suburban areas is much more affected by long-range transport of pollution and/or complex sources including domestic coal combustion, biomass burning, industrial and transportation, especially in three other seasons except winter, which is

  19. Size Distribution and Chemical Characteristic of Aerosols in Northwestern Black Sea Region of Turkey

    NASA Astrophysics Data System (ADS)

    Oztürk, Fatma; Keles, Melek; Halif Ngagine, Soulemane

    2016-04-01

    Size segregated PM samples were collected at the city center of Bolu, which is northwestern part of the Black Sea region of Turkey between 2015 and 2016. A cascade impactor was used for the collection of weekly PM samples on pre-fired quartz filters in eight different size ranges (9.0-10.0 μm, 5.8-9.0 μm, 4.7-5.8 μm, 3.3-4.7 μm, 2.1-3.3 μm, 1.1-2.1 μm, 0.65-1.1 μm, 0.43-0.65 μm). The collected samples were divided in three parts and each part was analyzed with different analytical technique. The first part of the filter was analyzed in terms of major ions (SO42-, NO3-, Cl-, NH4+, K+, Ca2+, Mg2+, Na+). A large suit of metals from Li to U were determined in the second fraction of the filter by means of ICPMS. Lastly, the third part of the filter was analyzed in terms of EC and OC. The preliminary results indicated that the PM mass depicted bimodal distribution and the average concentration of PM10 was about 100 μg/m3for a five week period. Both EC and OC showed bi-modal distribution while these two parameters were more enriched on smaller particles. The average concentrations of EC and OC in PM1 were determined as 4.1 and 40.6 μg/m3, respectively, indicating the secondary organic aerosol formation in Bolu ambient air. Among the major ions, SO42- and NH4+ depicted unimodal distribution having significantly higher concentrations in fine particles (< 1 μm) while the rest of the ions present bimodal distribution. Mass closure analysis will be applied to the generated data set and sources will be evaluated by applying PMF. This project was supported financially by Turkish Scientific and Technological Research Council (TÜBİTAK) with a project number 114Y429.

  20. Characteristics of atmospheric organic and elemental carbon aerosols in urban Beijing, China

    NASA Astrophysics Data System (ADS)

    Ji, Dongsheng; Zhang, Junke; He, Jun; Wang, Xiaoju; Pang, Bo; Liu, Zirui; Wang, Lili; Wang, Yuesi

    2016-01-01

    Organic carbon (OC) and elemental carbon (EC) in PM2.5 were measured hourly with a semicontinuous thermal-optical analyzer in urban Beijing, China, from Mar 1, 2013 to Feb 28, 2014. The annual mean concentrations of OC and EC in Beijing were 14.0 ± 11.7 and 4.1 ± 3.2 μg/m3, respectively. The concentrations observed in this study were lower than those of other reports over the past ten years; however, the concentrations were higher than those reported from most of the megacities in North America and Europe. These findings suggest that OC and EC remained at high levels despite the implementation of strict control measures to improve air quality. The OC and EC concentrations exhibited strong seasonality, with high values in the autumn and winter but low values in the spring and summer in Beijing. The diurnal OC and EC cycles were characterized by higher values at night and in the morning because of primary emissions, accumulations and low boundary-layer heights. Due to increasing photochemical activity, a well-defined OC peak was observed at approximately noon. The OC and EC concentrations followed typical lognormal patterns in which more than 75% of the OC samples had concentrations between 0.9 and 18.0 μg/m3 and 75% of the EC samples had concentrations between 0.4 and 5.6 μg/m3. An EC tracer method and combined EC tracer and K+ mass balance methods were used to estimate the contributions from secondary formation and biomass burning, respectively. High secondary organic carbon (SOC) concentrations were found in the autumn and winter due to low temperatures, which are favorable for the absorption and condensation of semi-volatile organic compounds on existing particles. High correlations were found between the estimated SOC in PM2.5 and the observed OOA (oxidized organic aerosol) in PM1; thus, the method proved to be effective and reliable. The annual average OCBiomass burning (OCbb) contribution to the total OC concentration was 18.4%, suggesting that biomass

  1. Revised Land Use Characteristic Dataset for Asia and Southwest Asia for the Navy Aerosol Analysis and Prediction System (NAAPS)

    NASA Astrophysics Data System (ADS)

    Walker, A. L.; Richardson, K.; Westphal, D. L.

    2002-12-01

    Presently, the Navy Aerosol Analysis and Prediction System (NAAPS) uses the U.S. Geological Survey (USGS) land use characteristic dataset to determine global dust emission areas. The USGS dataset was developed from Advanced Very High-Resolution Radiometer 1-km data from April 1992 to March 1993. In the past decade drastic changes in land and water use in Asia and Southwest Asia have quickly outdated this dataset. In China and Mongolia, age-old practices of farming and animal husbandry have been abandoned. Herders have too many animals in one location allowing the grassland to be eaten away and leaving vast areas of topsoil exposed and primed for removal by the wind. In the case of Southwest Asia, a four-year drought is in progress. Many of the wetlands and marshes in the river deltas are drying up from the lack of water runoff. To compound the problem several new dams were and are being built along the major watersheds. In particular, Iraq's dam building in the 1990's and politically driven draining of the Mesopotamian marshes between the Tigris and Euphrates rivers has lead to the near disappearance of this historical marshland. To incorporate these changes we are updating the USGS land use characteristic dataset using GIS-like software named ENVI (Environment for Visualizing Images), 1 km National Geophysical Data Center (NGDC) global topographical data, satellite imagery, and recently released governmental maps and reports. (For example, within the last two years the Chinese and Mongolian governments have released land degradation and desertification maps to satisfy the requirements set forth by United Nations Convention to Combat Desertification.) The steps taken to create the new land use characteristic database will be described in detail. Before (non-dust producing areas) and after (dust producing areas) examples will be shown.

  2. Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Junfeng; Ge, Xinlei; Chen, Yanfang; Shen, Yafei; Zhang, Qi; Sun, Yele; Xu, Jianzhong; Ge, Shun; Yu, Huan; Chen, Mindong

    2016-07-01

    In this work, the Aerodyne soot particle - aerosol mass spectrometer (SP-AMS) was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD) of China, for online characterization of the submicron aerosols (PM1). The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC) simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics). The average PM1 concentration was found to be 28.2 µg m-3, with organics (45 %) as the most abundant component, following by sulfate (19.3 %), nitrate (13.6 %), ammonium (11.1 %), rBC (9.7 %), and chloride (1.3 %). These PM1 species together can reconstruct ˜ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (< 100 nm vacuum aerodynamic diameter) were dominated by organics and rBC, while large particles had significant contributions from secondary inorganic species. Source apportionment of organic aerosols (OA) yielded four OA subcomponents, including hydrocarbon-like OA (HOA), cooking-related OA (COA), semi-volatile oxygenated OA (SV-OOA), and low-volatility oxygenated OA (LV-OOA). Overall, secondary organic aerosol (SOA, equal to the sum of SV-OOA and LV-OOA) dominated the total OA mass (55.5 %), but primary organic aerosol (POA, equal to the sum of HOA and COA) can outweigh SOA in the early morning and evening due to enhanced human activities. High OA concentrations were often associated with high mass fractions of POA and rBC, indicating the important role of anthropogenic emissions during heavy pollution events. The diurnal cycles of nitrate, chloride, and SV-OOA both showed good anti-correlations with air temperatures, suggesting their variations were likely driven by thermodynamic equilibria and gas-to-particle partitioning. On the other hand, in contrast to other species

  3. Physical and chemical characteristics of Mt. St. Helens airborne debris

    SciTech Connect

    Sedlacek, W.A.; Heiken, G.H.; Mroz, E.J.; Gladney, E.S.; Perrin, D.R.; Leifer, R.; Fisenne, I.; Hinchliffe, L.; Chuan, R.L.

    1980-01-01

    Tephra and aerosols from the May 18, 1980 eruption of Mt. St. Helens, Washington were sampled in the lower stratosphere with a WB-57F aircraft. The main body of the plume was intercepted over western Kansas on May 20, 48 hours after the eruption, at an altitude of 15.2 km. Concentrations on filter samples were 26 ng of SO/sub 4//g of air and 579 ng of ash/g of air. Angular glass pyroclasts ranged in size from 0.5 to 10 ..mu..m, with a mean grain size of 2 ..mu..m. Samples collected at altitudes of 16.7 and 12.5 km had only traces of SO/sub 4/ and ash. A second flight was flown, 72 hours after the eruption, on May 21. From north Texas to central Wyoming, at an altitude of 15.2 km, < 0.5 to 38 ng of ash/g of air and 1.0 to 2.2 ng of SO/sub 4//g of air were sampled. At an altitude of 18.3 km, from central Wyoming to NW New Mexico, the plume density and character were variable. Glassy pyroclasts similar to those sampled on the first flight range in size from 0.5 to 4 ..mu..m dia. Trace element analysis revealed some volatile element enrichment, but far less than previously observed in the plume from St. Augustine Volcano, 1976. Values of /sup 210/Po//sup 210/Pb were 0.7 to 1.32 comparable to the secular equilibrium value of 1.0 and far less than ratios previously reported by Lambert.

  4. The Characteristics of the Outdoor School Environment Associated with Physical Activity

    ERIC Educational Resources Information Center

    Haug, Ellen; Torsheim, Torbjorn; Sallis, James F.; Samdal, Oddrun

    2010-01-01

    The school is an important setting for physical activity. The purpose of the present study was to examine the association between physical environmental characteristics and participation in daily physical activity during school breaks. Data from 130 schools and 16 471 students (Grades 4-10) in Norway were obtained in 2004 through self-administered…

  5. PETN: Variation in Physical and Chemical Characteristics Related to Aging.

    SciTech Connect

    Monroe, D. C.; Laintz, K. E.; Kramer, J. F.; Peterson, P. D.

    2006-01-01

    Physical and chemical analyses of five PETN (pentaerythritol tetranitrate) batches have been conducted to assist in defining powder acceptance criteria for qualification of newly manufactured powders, as well as for examination of potential changes related to aging and thus changes in performance. Results showed that (1) repeatable Fisher Sub-Sieve Sizer measurements (which relate well to historic performance data) could be obtained with consistent sample setup and measurement techniques; (2) BET nitrogen adsorption estimates of surface area correlate well with Fisher measurements and appear less variable; (3) PharmaVision particle size analyses show promise in discriminating among PETN batches; and (4) SEMs are extremely useful in semi-quantitative discrimination among batches. Physical and chemical data will be related to performance data (to be obtained) to develop quantitative physical and chemical tests useful in predicting performance over time, i.e., as powders age.

  6. Analysis of the sensitivity of thermal infrared nadir satellite observations to the chemical and micro-physical properties of upper tropospheric-lower stratospheric sulphate aerosols

    NASA Astrophysics Data System (ADS)

    Sellitto, Pasquale; Sèze, Geneviève; Legras, Bernard

    2015-04-01

    Secondary sulphate aerosols are the predominant typology of aerosols in the upper troposphere/lower stratosphere (UTLS), and can have an important impact on radiative transfer and climate, cirrus formation and chemistry in the UTLS. Despite their importance, the satellite observation at the regional scale of sulphate aerosols in the UTLS is limited. In this work, we address the sensitivity of the thermal infrared satellite observations to secondary sulphate aerosols in the UTLS. The absorption properties of sulphuric acid/water droplets, for different sulphuric acid mixing ratios and temperatures, are systematically analysed. The absorption coefficients are derived by means of a Mie code, using refractive indexes taken from the GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques : Management and Study of Spectroscopic Information) spectroscopic database and log-normal size distributions with different effective radii and number concentrations. IASI (Infrared Atmospheric Sounding Interferometer) and SEVIRI (Spinning Enhanced Visible and Infrared Imager) pseudo-observations are generated using forward radiative transfer calculations performed with the 4A (Automatized Atmospheric Absorption Atlas) radiative transfer model, to estimate the impact of the absorption of idealized aerosol layers, at typical UTLS conditions, on the radiance spectra observed by these simulated satellite instruments. We found a marked spectral signature of these aerosol layers between 700 and 1200 cm-1, due to the absorption bands of the sulphate and bi-sulphate ions and the undissociated sulphuric acid, with absorption peaks at 1170 and 905 cm-1. Micro-windows with a sensitivity to chemical and micro-physical properties of the sulphate aerosol layer are identified, and the role of interfering species, and temperature and water vapour profile is discussed.

  7. Spray characteristics affected by physical properties of adjuvants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four drift adjuvants, Array, In-Place, Vector and Control, were tested and physical properties and spray spectrum parameters measured. Array had the highest conductivity, indicating a good potential for the electrostatic charging, and the highest shear viscosity. All adjuvants had very similar neut...

  8. Selected Characteristics of Persons in Physical Science: 1978.

    ERIC Educational Resources Information Center

    Palumbo, Thomas J.; And Others

    1980-01-01

    Statistical information, based on the 1978 survey in a series of biennial surveys known as the National Sample of Scientists and Engineers, sponsored by the National Science Foundation and conducted by the Bureau of the Census is presented. Individuals in the field of physical sciences are profiled, including chemists, physicists and astronomers,…

  9. Income, Family Characteristics, and Physical Violence toward Children

    ERIC Educational Resources Information Center

    Berger, L.M.

    2005-01-01

    Objective:: This paper discusses the ways in which existing microeconomic theories of partner abuse, intra-family bargaining, and distribution of resources within families may contribute to our current understanding of physical child abuse. The empirical implications of this discussion are then tested on data from the 1985 National Family Violence…

  10. Real-time measurements of ambient aerosols in a polluted Indian city: Sources, characteristics, and processing of organic aerosols during foggy and nonfoggy periods

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhishek; Bhattu, Deepika; Gupta, Tarun; Tripathi, Sachchida N.; Canagaratna, Manjula R.

    2015-09-01

    A detailed time-resolved chemical characterization of ambient nonrefractory submicron aerosols (NR-PM1) was conducted for the first time in India. The measurements were performed during the winter (November 2011 to January 2012) in a heavily polluted city of Kanpur, which is situated in the Indo-Gangetic Plain. Real-time measurements provided new insights into the sources and evolution of organic aerosols (OA) that could not be obtained using previously deployed filter-based measurements at this site. The average NR-PM1 loading was very high (>100 µg/m3) throughout the study, with OA contributing approximately 70% of the total aerosol mass. Source apportionment of the OA using positive matrix factorization revealed large contributions from fresh and aged biomass burning OA throughout the entire study period. A back trajectory analysis showed that the polluted air masses were affected by local sources and distant source regions where the burning of paddy residues occurs annually during winter. Several fog episodes were encountered during the study, and the OA composition varied between foggy and nonfoggy periods, with higher oxygen to carbon (O/C) ratios during the foggy periods. The evolution of OA and their elemental ratios (O:C and H:C) were investigated for the possible effects of fog processing.

  11. Physical and chemical properties of the volcanic ash aerosol from the Eyjafjoll volcano eruption (Invited)

    NASA Astrophysics Data System (ADS)

    Baltensperger, U.; Eyjafioll Volcano Atmospheric Observation Consortium

    2010-12-01

    The eruption of the Eyjafjoll volcano in Iceland has stalled flight traffic in large regions of Europe. Decision makers had to base their decisions mainly on model calculations for the volcanic plume dispersion. The damaging potential and thus the corresponding standard of the volcanic ash are related to mass concentration, which is difficult to measure directly in the air. This paper presents data from in situ measurements of the ash at the high mountain site Jungfraujoch, Switzerland (3580 m asl), where, among other variables, the size distribution, the mass concentration, as well as the light scattering and absorption coefficients were continuously determined. Based on these data the mass extinction efficiency, i.e., the relationship between the mass concentration of the volcanic ash and its extinction coefficient was determined for this site. The temporal evolution of the size distribution and mass concentrations with transport distance due to dilution, settling, secondary aerosol formation from SO2 etc. was modeled with a combination of state-of-the-art models, and the results were compared to available aircraft observations. In this way the mass extinction efficiency for numerous lidar sites in Europe were determined, which allowed for calculation of mass concentration profiles at these locations.

  12. A European aerosol phenomenology—2: chemical characteristics of particulate matter at kerbside, urban, rural and background sites in Europe

    NASA Astrophysics Data System (ADS)

    Putaud, Jean-P.; Raes, Frank; Van Dingenen, Rita; Brüggemann, Erika; Facchini, M.-Cristina; Decesari, Stefano; Fuzzi, Sandro; Gehrig, Robert; Hüglin, Cristoph; Laj, Paolo; Lorbeer, Gundi; Maenhaut, Willy; Mihalopoulos, Nikolaos; Müller, Konrad; Querol, Xavier; Rodriguez, Sergio; Schneider, Jürgen; Spindler, Gerald; Brink, Harry ten; Tørseth, Kjetil; Wiedensohler, Alfred

    This paper synthesizes data on aerosol (or particulate matter, PM) chemical characteristics, which were obtained in European aerosol research activities at natural, rural, near-city, urban, and kerbside sites over the past decade. It includes only two (nearby) sites in the semi-arid Mediterranean area, and lacks data from Eastern Europe. PM chemical compositions are compared with the PM mass concentrations in PM10, PM2.5, and further size resolved PM fractions (chemical mass closure). Such data sets are more comprehensive than those currently provided by air quality monitoring networks (e.g. EMEP, EUROAIRNET). Data available from 24 sites in Europe were reviewed. They were processed and plotted to allow comparisons in spite of differences in the sampling and analytical techniques used in various studies. A number of conclusions are drawn among which are the following. Organic matter appears to be the major component of PM10 and PM2.5, except at natural and rural background sites, where sulphate contribution may be larger. Mineral dust shows up as a major component of PM10 at kerbside sites. Black carbon contributes 5-10% to PM2.5 and somewhat less to PM10 at all sites, including the natural background sites. Its contribution seems higher (15-20%) at some of the kerbside sites, but these data may be affected by analytical artefacts. On days when PM10 >50 μg m -3, nitrate concentrations can overtake organic matter concentrations in PM10 and PM2.5. High PM concentration episodes are often observed in cold periods, when the pollutant dispersion is least. Measurements indicate that the condensation in the particle phase of semi-volatile species like nitrate and (unspecified) organics is also favoured by cold temperatures. In particles with a diameter <150 nm (i.e., most atmospheric particles), organic matter and black carbon are by far the major components. More data are known to be available within the scientific community, which could enrich the present data set and

  13. Can basin land use effects on physical characteristics of streams be determined at broad geographic scales?

    PubMed

    Goldstein, Robert M; Carlisle, Daren M; Meador, Michael R; Short, Terry M

    2007-07-01

    The environmental setting (e.g., climate, topography, geology) and land use affect stream physical characteristics singly and cumulatively. At broad geographic scales, we determined the importance of environmental setting and land use in explaining variation in stream physical characteristics. We hypothesized that as the spatial scale decreased from national to regional, land use would explain more of the variation in stream physical characteristics because environmental settings become more homogeneous. At a national scale, stepwise linear regression indicated that environmental setting was more important in explaining variability in stream physical characteristics. Although statistically discernible, the amount of variation explained by land use was not remarkable due to low partial correlations. At level II ecoregion spatial scales (southeastern USA plains, central USA plains, and a combination of the western Cordillera and the western interior basins and ranges), environmental setting variables were again more important predictors of stream physical characteristics, however, as the spatial scale decreased from national to regional, the portion of variability in stream physical characteristics explained by basin land use increased. Development of stream habitat indicators of land use will depend upon an understanding of relations between stream physical characteristics and environmental factors at multiple spatial scales. Smaller spatial scales will be necessary to reduce the confounding effects of variable environmental settings before the effects of land use can be reliably assessed. PMID:17106774

  14. Can basin land use effects on physical characteristics of streams be determined at broad geographic scales?

    USGS Publications Warehouse

    Goldstein, R.M.; Carlisle, D.M.; Meador, M.R.; Short, T.M.

    2007-01-01

    The environmental setting (e.g., climate, topography, geology) and land use affect stream physical characteristics singly and cumulatively. At broad geographic scales, we determined the importance of environmental setting and land use in explaining variation in stream physical characteristics. We hypothesized that as the spatial scale decreased from national to regional, land use would explain more of the variation in stream physical characteristics because environmental settings become more homogeneous. At a national scale, stepwise linear regression indicated that environmental setting was more important in explaining variability in stream physical characteristics. Although statistically discernible, the amount of variation explained by land use was not remarkable due to low partial correlations. At level II ecoregion spatial scales (southeastern USA plains, central USA plains, and a combination of the western Cordillera and the western interior basins and ranges), environmental setting variables were again more important predictors of stream physical characteristics, however, as the spatial scale decreased from national to regional, the portion of variability in stream physical characteristics explained by basin land use increased. Development of stream habitat indicators of land use will depend upon an understanding of relations between stream physical characteristics and environmental factors at multiple spatial scales. Smaller spatial scales will be necessary to reduce the confounding effects of variable environmental settings before the effects of land use can be reliably assessed. ?? Springer Science+Business Media B.V. 2006.

  15. Evaluation of aerosol sizing characteristic of an impactor using imaging plate technique.

    PubMed

    Rahman, Naureen Mahbub; Iida, Takao; Saito, Fumihiro; Koarashi, Jun; Yamasaki, Keizou; Yamazawa, Hiromi; Moriizumi, Jun

    2007-01-01

    The activity-size distribution of radon decay products are normally determined using two approaches: direct and indirect. The present study utilises the direct approach to evaluate sizing information of a low pressure cascade impactor using imaging plate (IP) technique for radon decay products. The experiment verified the use of the collection media as suggested by the manufacturer of impactor and proposed a few improvements toward sizing characteristics of impactor. The obtained relative activity-size distribution of radon decay products presents a sharp unimodal log-normal distribution of the particle characterised by activity median aerodynamic diameter (AMAD) of 268 nm and geometric standard deviation (sigma(g)) of 1.66. The obtained data with all the suggested improvements were evaluated by the data obtained from a scanning mobility particle sizer (SMPS, Model 3934, TSI Inc), as reference data. The verification lead to a derivative area ratio of 0.803 between the reference and experimental data. PMID:16936289

  16. Spectra Aerosol Light Scattering and Absorption for Laboratory and Urban Aerosol

    NASA Astrophysics Data System (ADS)

    Gyawali, Madhu S.

    Atmospheric aerosols considerably influence the climate, reduce visibility, and cause problems in human health. Aerosol light absorption and scattering are the important factors in the radiation transfer models. However, these properties are associated with large uncertainties in climate modeling. In addition, atmospheric aerosols widely vary in composition and size; their optical properties are highly wavelength dependent. This work presents the spectral dependence of aerosol light absorption and scattering throughout the ultraviolet to near-infrared regions. Data were collected in Reno, NV from 2008 to 2010. Also presented in this study are the aerosol optical and physical properties during carbonaceous aerosols and radiative effects study (CARES) conducted in Sacramento area during 2010. Measurements were made using photoacoustic instruments (PA), including a novel UV 355 nm PA of our design and manufacture. Comparative analyses are presented for three main categories: (1) aerosols produced by wildfires and traffic emissions, (2) laboratory-generated and wintertime ambient urban aerosols, and (3) urban plume and biogenic emissions. In these categories, key questions regarding the light absorption by secondary organic aerosols (SOA), so-called brown carbon (BrC), and black carbon (BC) will be discussed. An effort is made to model the emission and aging of urban and biomass burning aerosol by applying shell-core calculations. Multispectral PA measurements of aerosols light absorption and scattering coefficients were used to calculate the Angstrom exponent of absorption (AEA) and single scattering albedo (SSA). The AEA and SSA values were analyzed to differentiate the aerosol sources. The California wildfire aerosols exhibited strong wavelength dependence of aerosol light absorption with AEA as lambda -1 for 405 and 870 nm, in contrast to the relatively weak wavelength dependence of traffic emissions aerosols for which AEA varied approximately as lambda-1. By using

  17. TAGISH LAKE METEORITE FALL : INTERPRETATION OF FIREBALL PHYSICAL CHARACTERISTICS.

    SciTech Connect

    Brown, P. G.; ReVelle, D. O.

    2001-01-01

    We have analyzed available instrumental and eyewitness records associated with the fireball leading to the fall of the Tagish Lake meteorite. Initial chemical and physical studies of this carbonaceous chondrite have shown it to be unique. It is one of the most primitive meteorites yet recovered and extremely friable. By determining the original bodies trajectory, velocity and physical breakup in the atmosphere we can characterise the fireball as intermediate between Type II and Type IIIa, following the classification of Ceplecha et al. Modelling of the object suggests an initial porosity of the pre-atmospheric body in the range 40-60%. The initial fragmentation occurred under less than 0.3 MPa dynamic pressure. Determination of Tagish Lake's orbit suggests a nominal linkage to parent bodies in the main asteroid belt, though association with short-period comets cannot be strictly excluded. It is suggested that Tagish Lake represents an intermediate object between chondritic asteroids and cometary bodies and our results are consistent with a linkage to D-class asteroids based on results from reflectance-spectra work.

  18. Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China during 2014 APEC summit

    NASA Astrophysics Data System (ADS)

    Chen, C.; Sun, Y. L.; Xu, W. Q.; Du, W.; Zhou, L. B.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Gao, Z. Q.; Zhang, Q.; Worsnop, D. R.

    2015-08-01

    The megacity of Beijing has experienced frequent severe fine particle pollution during the last decade. Although the sources and formation mechanisms of aerosol particles have been extensively investigated on the basis of ground measurements, real-time characterization of aerosol particle composition and sources above the urban canopy in Beijing is rare. In this study, we conducted real-time measurements of non-refractory submicron aerosol (NR-PM1) composition at 260 m at the 325 m Beijing Meteorological Tower (BMT) from 10 October to 12 November 2014, by using an aerosol chemical speciation monitor (ACSM) along with synchronous measurements of size-resolved NR-PM1 composition at near ground level using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). The NR-PM1 composition above the urban canopy was dominated by organics (46 %), followed by nitrate (27 %) and sulfate (13 %). The high contribution of nitrate and high NO3-/SO42- mass ratios illustrate an important role of nitrate in particulate matter (PM) pollution during the study period. The organic aerosol (OA) was mainly composed by secondary OA (SOA), accounting for 61 % on an average. Different from that measured at the ground site, primary OA (POA) correlated moderately with SOA, likely suggesting a high contribution from regional transport above the urban canopy. The Asia-Pacific Economic Cooperation (APEC) summit with strict emission controls provides a unique opportunity to study the impacts of emission controls on aerosol chemistry. All aerosol species were shown to have significant decreases of 40-80 % during APEC from those measured before APEC, suggesting that emission controls over regional scales substantially reduced PM levels. However, the bulk aerosol composition was relatively similar before and during APEC as a result of synergetic controls of aerosol precursors such as SO2, NOx, and volatile organic compounds (VOCs). In addition to emission controls, the routine

  19. Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China, during the 2014 APEC summit

    NASA Astrophysics Data System (ADS)

    Chen, C.; Sun, Y. L.; Xu, W. Q.; Du, W.; Zhou, L. B.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Gao, Z. Q.; Zhang, Q.; Worsnop, D. R.

    2015-11-01

    The megacity of Beijing has experienced frequent severe fine particle pollution during the last decade. Although the sources and formation mechanisms of aerosol particles have been extensively investigated on the basis of ground measurements, real-time characterization of aerosol particle composition and sources above the urban canopy in Beijing is rare. In this study, we conducted real-time measurements of non-refractory submicron aerosol (NR-PM1) composition at 260 m at the Beijing 325 m meteorological tower (BMT) from 10 October to 12 November 2014, by using an aerosol chemical speciation monitor (ACSM) along with synchronous measurements of size-resolved NR-PM1 composition near ground level using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The NR-PM1 composition above the urban canopy was dominated by organics (46 %), followed by nitrate (27 %) and sulfate (13 %). The high contribution of nitrate and high NO3- / SO42- mass ratios illustrates an important role of nitrate in particulate matter (PM) pollution during the study period. The organic aerosol (OA) was mainly composed of secondary OA (SOA), accounting for 61 % on an average. Different from that measured at the ground site, primary OA (POA) correlated moderately with SOA, likely suggesting a high contribution from regional transport above the urban canopy. The Asia-Pacific Economic Cooperation (APEC) summit with strict emission controls provides a unique opportunity to study the impacts of emission controls on aerosol chemistry. All aerosol species were shown to have significant decreases of 40-80 % during APEC from those measured before APEC, suggesting that emission controls over regional scales substantially reduced PM levels. However, the bulk aerosol composition was relatively similar before and during APEC as a result of synergetic controls of aerosol precursors. In addition to emission controls, the routine circulations of mountain-valley breezes were also found to play

  20. Comprehensive Mapping and Characteristic Regimes of Aerosol Effects on the Formation and Evolution of Pyro-Convective Clouds

    SciTech Connect

    Chang, Di; Cheng, Yafang; Reutter, Philipp; Trentmann, Jrg; Burrows, Susannah M.; Spichtinger, Peter; Nordmann, Stephan; Andreae, M. O.; Poschl, U.; Su, Hang

    2015-09-21

    A recent parcel model study (Reutter et al., 2009) showed three deterministic regimes of initial cloud droplet formation characterized by ratios of aerosol concentrations (NCN) to updraft velocities. This analysis, however, did not reveal how these regimes evolve during the subsequent development of clouds. To address this issue, we employed the Active Tracer High Resolution Atmospheric Model with full microphysics and extended the model simulation from the cloud base to the entire column of a single pyro-convective mixed-phase cloud. A series of 2-D simulations (over 1000) were performed over a wide range of NCN and dynamic conditions. The integrated concentration of hydrometeors over the full spatial and temporal scales was used to evaluate the aerosol and dynamic effects. The results show that: (1) the three regimes for cloud condensation nuclei (CCN) activation in the parcel model (namely aerosol-limited, updraft-limited, and transitional regimes) still exist within our simulations, but the net production of raindrops and frozen particles occurs mostly within the updraft-limited regime. (2) Generally, elevated aerosols enhance the formation of cloud droplets and frozen particles. The response of raindrops and precipitation to aerosols is more complicated and can be either positive or negative as a function of aerosol concentrations. The most negative effect was found for a value of NCN of ~1000 to 3000 cm-3. (3) The employment of nonlinear (dynamic and microphysical) processes leads to a more complicated and unstable response of clouds to aerosol perturbation compared with the parcel model results. Therefore, conclusions drawn from limited case studies might require caveats regarding their representativeness, and high-resolution sensitivity studies over a wide range of aerosol concentrations and updraft velocities are highly recommended.

  1. Hydro-physical Characteristics of Selected Media Used for Containerized Agriculture Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Containerized plant production represents an extremely intensive agricultural practice with large amounts of water and fertilizer application. Hydro-physical characteristics such as water infiltration, texture and structure, particle size distribution affect the quality of the media used in containe...

  2. High-speed civil transport impact: Role of sulfate, nitric acid trihydrate, and ice aerosols studied with a two-dimensional model including aerosol physics

    SciTech Connect

    Pitari, G.; Ricciardulli, L.; Visconti, G.; Rizi, V.

    1993-12-20

    The authors discuss a two-dimensional model used to study the atmospheric interactions of ozone with exhaust gases from high speed civil transport (HSCT) fleets. Their model encompases the stratosphere and troposphere, includes photochemical reactions as part of the sulfur cycle, and models sulfuric acid aerosols. The inclusion of heterogeneous chemistry effects tempers the impact of nitrogen oxide emissions from HSCT on ozone depletion, in support of previous work from other studies.

  3. Quantification of Optical and Physical Properties of Combustion-Generated Carbonaceous Aerosols (

    PubMed Central

    Perera, Inoka Eranda; Litton, Charles D.

    2016-01-01

    A series of experiments were conducted to quantify and characterize the optical and physical properties of combustion-generated aerosols during both flaming and smoldering combustion of three materials common to underground mines—Pittsburgh Seam coal, Styrene Butadiene Rubber (a common mine conveyor belt material), and Douglas-fir wood—using a combination of analytical and gravimetric measurements. Laser photometers were utilized in the experiments for continuous measurement of aerosol mass concentrations and for comparison to measurements made using gravimetric filter samples. The aerosols of interest lie in the size range of tens to a few hundred nanometers, out of range of the standard photometer calibration. To correct for these uncertainties, the photometer mass concentrations were compared to gravimetric samples to determine if consistent correlations existed. The response of a calibrated and modified combination ionization/photoelectric smoke detector was also used. In addition, the responses of this sensor and a similar, prototype ionization/photoelectric sensor, along with discrete angular scattering, total scattering, and total extinction measurements, were used to define in real time the size, morphology, and radiative transfer properties of these differing aerosols that are generally in the form of fractal aggregates. SEM/TEM images were also obtained in order to compare qualitatively the real-time, continuous experimental measurements with the visual microscopic measurements. These data clearly show that significant differences exist between aerosols from flaming and from smoldering combustion and that these differences produce very different scattering and absorption signatures. The data also indicate that ionization/photoelectric sensors can be utilized to measure continuously and in real time aerosol properties over a broad spectrum of applications related to adverse environmental and health effects.

  4. Characteristics of carbonaceous aerosols: Impact of biomass burning and secondary formation in summertime in a rural area of the North China Plain.

    PubMed

    Yao, Lan; Yang, Lingxiao; Chen, Jianmin; Wang, Xinfeng; Xue, Likun; Li, Weijun; Sui, Xiao; Wen, Liang; Chi, Jianwei; Zhu, Yanhong; Zhang, Junmei; Xu, Caihong; Zhu, Tong; Wang, Wenxing

    2016-07-01

    To determine the characteristics of carbonaceous aerosols in rural areas of the North China Plain, field measurements were conducted at Yucheng (YC) in the summers of 2013 and 2014. The concentrations of carbonaceous aerosols at YC exhibited clear diurnal variation, with higher concentrations in the early morning and at night and lower concentrations during the afternoon hours. The mass-balance method designed for particulate matter smaller than 2.5μm (PM2.5) was used to calculate the organic matter (OM)/organic carbon (OC) ratio. The value obtained, 2.07±0.05, was suggested as a reference to estimate organics in PM2.5 in rural areas of the North China Plain. Biomass burning was identified to be a significant source of carbonaceous aerosols; approximately half of the samples obtained at YC were affected by biomass burning during summer 2013. Case studies revealed that biomass burning accounted for up to 52.6% of the OC and 51.1% of the elemental carbon in PM2.5 samples. The organic coatings observed on sulphur-rich and potassium-rich particles indicated the formation of secondary organic aerosols (SOA) from the oxidation of precursor volatile organic compounds (VOCs) during the aging of smoke released from biomass burning. Based on the evolution of the VOCs, the contribution of VOCs oxidation to SOA concentration was 3.21 and 1.07μgm(-3)ppm(-1) CO under conditions of low nitrogen oxide (NOx) and high NOx, respectively. Aromatics (e.g. benzene, toluene, xylene and ethylbenzene) made the greatest contribution to SOA concentration (88.4% in low-NOx conditions and 80.6% in high-NOx conditions). The results of the study offer novel insights into the effects of biomass burning on the carbonaceous aerosols and SOA formation in polluted rural areas. PMID:27031303

  5. Physical characteristics of a commercial electronic portal imaging device.

    PubMed

    Althof, V G; de Boer, J C; Huizenga, H; Stroom, J C; Visser, A G; Swanenburg, B N

    1996-11-01

    An electronic portal imaging device (EPID) for use in radiotherapy with high energy photons has been under development since 1985 and has been in clinical use since 1988. The x-ray detector consists of a metal plate/fluorescent screen combination, which is monitored by a charge-coupled device (CDD)-camera. This paper discusses the physical quantities governing image quality. A model which describes the signal and noise propagation through the detector is presented. The predicted contrasts and signal-to-noise ratios are found to be in agreement with measurements based on the EPID images. Based on this agreement the visibility of low contrast structures in clinical images has been calculated with the model. Sufficient visibility of relevant structures (4-10 mm water-equivalent thickness) has been obtained down to a delivered dose of 4 cGy at dose maximum. It is found that the described system is not limited by quantum noise but by camera read-out noise. In addition we predict that with a new type of CCD sensor the signal-to-noise ratio can be increased by a factor of 5 at small doses, enabling high quality imaging, for most relevant clinical situations, with a patient dose smaller than 4 cGy. The latter system would be quantum noise limited. PMID:8947896

  6. Physical characteristics of summer sea ice across the Arctic Ocean

    USGS Publications Warehouse

    Tucker, W. B., III; Gow, A.J.; Meese, D.A.; Bosworth, H.W.; Reimnitz, E.

    1999-01-01

    Sea ice characteristics were investigated during July and August on the 1994 transect across the Arctic Ocean. Properties examined from ice cores included salinity, temperature, and ice structure. Salinities measured near zero at the surface, increasing to 3-4??? at the ice-water interface. Ice crystal texture was dominated by columnar ice, comprising 90% of the ice sampled. Surface albedos of various ice types, measured with radiometers, showed integrated shortwave albedos of 0.1 to 0.3 for melt ponds, 0.5 for bare, discolored ice, and 0.6 to 0.8 for a deteriorated surface or snow-covered ice. Aerial photography was utilized to document the distribution of open melt ponds, which decreased from 12% coverage of the ice surface in late July at 76??N to almost none in mid-August at 88??N. Most melt ponds were shallow, and depth bore no relationship to size. Sediment was pervasive from the southern Chukchi Sea to the north pole, occurring in bands or patches. It was absent in the Eurasian Arctic, where it had been observed on earlier expeditions. Calculations of reverse trajectories of the sediment-bearing floes suggest that the southernmost sediment was entrained during ice formation in the Beaufort Sea while more northerly samples probably originated in the East Siberian Sea, some as far west as the New Siberian Islands.

  7. Identifying the Common Characteristics of Comprehensive School Physical Activity Programs in Louisiana

    ERIC Educational Resources Information Center

    Deslatte, Kyrie'; Carson, Russell L.

    2014-01-01

    The purpose of this project was to (a) determine the common characteristics of current comprehensive school physical activity programs (CSPAP) in Louisiana and (b) identify strategies for implementing a CSPAP. Four individuals (i.e., one physical education teacher, one principal, and two classroom teachers) were recruited from three public schools…

  8. How Student Characteristics Affect Girls' and Boys' Verbal Engagement in Physics Instruction

    ERIC Educational Resources Information Center

    Jurik, Verena; Groschner, Alexander; Seidel, Tina

    2013-01-01

    This study investigated how student characteristics predict the nature of girls' and boys' verbal interactions with their teachers in physics classes. The sample included (N = 1378) students from 81 randomly selected high-school physics classrooms in Germany and the German-speaking part of Switzerland. At the beginning of the school year, the…

  9. Levels and Characteristics of Physical Activity among a College Student Cohort

    ERIC Educational Resources Information Center

    Miller, Kim; Staten, Ruth R.; Rayens, Mary Kay; Noland, Melody

    2005-01-01

    The purpose of this study was to assess physical activity levels and the relationships between activity and personal characteristics among a cohort of college students and to determine personal characteristics that predict activity. A sample of 1,700 undergraduates was mailed a survey that requested demographic information and assessed health…

  10. Handwriting Characteristics among Secondary Students with and without Physical Disabilities: A Study with a Computerized Tool

    ERIC Educational Resources Information Center

    Li-Tsang, Cecilia W. P.; Au, Ricky K. C.; Chan, Michelle H. Y.; Chan, Lily W. L.; Lau, Gloria M. T.; Lo, T. K.; Leung, Howard W. H.

    2011-01-01

    The purpose of the present study was to investigate the handwriting characteristics of secondary school students with and without physical disabilities (PD). With the use of a computerized Chinese Handwriting Assessment Tool (CHAT), it was made possible to objectively assess and analyze in detail the handwriting characteristics of individual…

  11. Generation and physical characteristics of the LANDSAT-1, -2 and -3 MSS computer compatible tapes

    NASA Technical Reports Server (NTRS)

    Thomas, V. L.

    1977-01-01

    The generation and format of the LANDSAT 1, 2, and 3 system corrected multispectral scanner computer compatible tapes are discussed. Included in the discussion are the spacecraft sensors, scene characteristics, the transmission of data, and the conversion of the data to computer compatible tapes. Also included in the discussion are geometric and radiometric corrections, tape formats, and the physical characteristics of the tape.

  12. Generation and physical characteristics of the ERTS MSS system corrected computer compatible tapes

    NASA Technical Reports Server (NTRS)

    Thomas, V. L.

    1973-01-01

    The generation and format are discussed of the ERTS system corrected multispectral scanner computer compatible tapes. The discussion includes spacecraft sensors, scene characteristics, data transmission, and conversion of data to computer compatible tapes at the NASA Data Processing Facility. Geometeric and radiometric corrections, tape formats, and the physical characteristics of the tapes are also included.

  13. Global Aerosol Remote Sensing from MODIS

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Kaufman, Yoram J.; Remer, Lorraine A.; Chu, D. Allen; Mattoo, Shana; Tanre, Didier; Levy, Robert; Li, Rong-Rong; Martins, Jose V.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The physical characteristics, composition, abundance, spatial distribution and dynamics of global aerosols are still very poorly known, and new data from satellite sensors have long been awaited to improve current understanding and to give a boost to the effort in future climate predictions. The derivation of aerosol parameters from the MODerate resolution Imaging Spectro-radiometer (MODIS) sensors aboard the Earth Observing System (EOS) Terra and Aqua polar-orbiting satellites ushers in a new era in aerosol remote sensing from space. Terra and Aqua were launched on December 18, 1999 and May 4, 2002 respectively, with daytime equator crossing times of approximately 10:30 am and 1:30 pm respectively. Several aerosol parameters are retrieved at 10-km spatial resolution (level 2) from MODIS daytime data. The MODIS aerosol algorithm employs different approaches to retrieve parameters over land and ocean surfaces, because of the inherent differences in the solar spectral radiance interaction with these surfaces. The parameters retrieved include: aerosol optical thickness (AOT) at 0.47, 0.55 and 0.66 micron wavelengths over land, and at 0.47, 0.55, 0.66, 0.87, 1.2, 1.6, and 2.1 micron over ocean; Angstrom exponent over land and ocean; and effective radii, and the proportion of AOT contributed by the small mode aerosols over ocean. To ensure the quality of these parameters, a substantial part of the Terra-MODIS aerosol products were validated globally and regionally, based on cross correlation with corresponding parameters derived from ground-based measurements from AERONET (AErosol RObotic NETwork) sun photometers. Similar validation efforts are planned for the Aqua-MODIS aerosol products. The MODIS level 2 aerosol products are operationally aggregated to generate global daily, eight-day (weekly), and monthly products at one-degree spatial resolution (level 3). MODIS aerosol data are used for the detailed study of local, regional, and global aerosol concentration

  14. Physical characteristics of bright Class I methanol masers

    NASA Astrophysics Data System (ADS)

    Leurini, S.; Menten, K. M.; Walmsley, C. M.

    2016-07-01

    Context. Class I methanol masers are thought to be tracers of interstellar shock waves. However, they have received relatively little attention mostly as a consequence of their low luminosities compared to other maser transitions. This situation has changed recently and Class I methanol masers are now routinely used as signposts of outflow activity especially in high extinction regions. The recent detection of polarisation in Class I lines now makes it possible to obtain direct observational information about magnetic fields in interstellar shocks. Aims: We make use of newly calculated collisional rate coefficients for methanol to investigate the excitation of Class I methanol masers and to reconcile the observed Class I methanol maser properties with model results. Methods: We performed large velocity gradient calculations with a plane-parallel slab geometry appropriate for shocks to compute the pump and loss rates which regulate the interactions of the different maser systems with the maser reservoir. We study the dependence of the pump rate coefficient, the maser loss rate, and the inversion efficiency of the pumping scheme of several Class I masers on the physics of the emitting gas. Results: We predict inversion in all transitions where maser emission is observed. Bright Class I methanol masers are mainly high-temperature (>100 K) high-density (n(H2) ~ 107-108 cm-3) structures with methanol maser emission measures, ξ, corresponding to high methanol abundances close to the limits set by collisional quenching. Our model predictions reproduce reasonably well most of the observed properties of Class I methanol masers. Class I masers in the 25 GHz series are the most sensitive to the density of the medium and mase at higher densities than other lines. Moreover, even at high density and high methanol abundances, their luminosity is predicted to be lower than that of the 44 GHz and 36 GHz masers. Our model predictions also reflect the observational result that the

  15. Comparison of physical and chemical properties of ambient aerosols during the 2009 haze and non-haze periods in Southeast Asia.

    PubMed

    Xu, Jingsha; Tai, Xuhong; Betha, Raghu; He, Jun; Balasubramanian, Rajasekhar

    2015-10-01

    Recurrent smoke-haze episodes that occur in Southeast Asia (SEA) are of much concern because of their environmental and health impacts. These haze episodes are mainly caused by uncontrolled biomass and peat burning in Indonesia. Airborne particulate matter (PM) samples were collected in the southwest coast of Singapore from 16 August to 9 November in 2009 to assess the impact of smoke-haze episodes on the air quality due to the long-range transport of biomass and peat burning emissions. The physical and chemical characteristics of PM were investigated during pre-haze, smoke-haze, and post-haze periods. Days with PM2.5 mass concentrations of ≥35 μg m(-3) were considered as smoke-haze events. Using this criterion, out of the total 82 sampling days, nine smoke-haze events were identified. The origin of air masses during smoke-haze episodes was studied on the basis of HYSPLIT backward air trajectory analysis for 4 days. In terms of the physical properties of PM, higher particle surface area concentrations and particle gravimetric mass concentrations were observed during the smoke-haze period, but there was no consistent pattern for particle number concentrations during the haze period as compared to the non-haze period except that there was a significant increase at about 08:00, which could be attributed to the entrainment of PM from aloft after the breakdown of the nocturnal inversion layer. As for the chemical characteristics of PM, among the six key inorganic water-soluble ions (Cl(-), NO3(-), nss-SO4(2-), Na(+), NH4(+), and nss-K(+)) measured in this study, NO3(-), nss-SO4(2-), and NH4(+) showed a significant increase in their concentrations during the smoke-haze period together with nss-K(+). These observations suggest that the increased atmospheric loading of PM with higher surface area and increased concentrations of optically active secondary inorganic aerosols [(NH4)2SO4 or NH4HSO4 and NH4NO3] resulted in the atmospheric visibility reduction in SEA due to

  16. Atmospheric Aging and Its Impacts on Physical Properties of Soot Aerosols: Results from the 2009 SHARP/SOOT Campaign

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Khalizov, A. F.; Zheng, J.; Reed, C. C.; Collins, D. R.; Olaguer, E. P.

    2009-12-01

    Atmospheric aerosols impact the Earth energy balance directly by scattering solar radiation back to space and indirectly by changing the albedo, frequency, and lifetime of clouds. Carbon soot (or black carbon) produced from incomplete combustion of fossil fuels and biomass burning represents a major component of primary aerosols. Because of high absorption cross-sections over a broad range of the electromagnetic spectra, black carbon contributes significantly to climate change by direct radiative forcing and is the second most important component causing global warming after carbon dioxide. In areas identified as aerosol hotspots, which include many megacities, solar heating by soot-containing aerosols is roughly comparable to heating due to greenhouse gases. In addition, light absorbing soot aerosols may reduce photolysis rates at the surface level, producing a noticeable impact on photochemistry. Enhanced light absorption and scattering by soot can stabilize the atmosphere, retarding vertical transport and exacerbating accumulation of gaseous and particulate matter (PM) pollutants within the planetary boundary layer. Less surface heating and atmospheric stabilization may decrease formation of clouds, and warming in the atmosphere can evaporate existing cloud droplets by lowering relative humidity. Furthermore, soot-containing aerosols represent a major type of PM that has adverse effects on human health. When first emitted, soot particles are low-density aggregates of loosely connected primary spherules. Freshly emitted soot particles are typically hydrophobic, but may become cloud condensation nuclei (CCN) during atmospheric aging by acquiring hydrophilic coatings. Hygroscopic soot particles, being efficient CCN, can exert indirect forcing on climate. In this talk, results will be presented on measurements of soot properties during the 2009 SHARP/SOOT Campaign. Ambient aerosols and fresh soot particles injected into a captured air chamber were monitored to

  17. Influence of Morphological Characteristics on Physical and Physiological Performances of Tunisian Elite Male Handball Players

    PubMed Central

    Moncef, Cherif; Said, Mohamed; Olfa, Najlaoui; Dagbaji, Gomri

    2012-01-01

    Purpose The purpose of this study was to describe the body structure and morphological characteristics of Tunisian elite handball players, and to determine the effect of these variables on functional and physical performance levels. Methods A sample of 42 male handball players (mean age 21.98±3.24 years; training duration 12 years) at international level was submitted to a test battery comprising morphological, physical and physiological assessments. Tests were yo-yo intermittent recovery test, squat jump test, countermovement jump test, vertical-jump test, and Repeated sprint Ability. Measures for assessment of anthropometric characteristics were age, size, weight, body mass index, body fat, fat mass and thin mass. Results Weight was negatively correlated to the squat jump and the countermovement jump performance. Age, weight, and body composition measures (fat and thin body mass) were additionally negatively related to the maximal oxygen uptake, and to the maximal velocity obtained in the Yo-Yo recovery test. No relationship was found between size, body mass index, body fat and the physical abilities considered. Concerning the effects of physical characteristics on the functional performances, we can note a positive relationship between squat jump, countermovement jump, and the yo-yo recovery test performance. No relationship was found between vertical jump, repeated sprint ability, and the physiological performances. Conclusions Study results point to the existence of strong correlation between morphological and physical characteristics with functional characteristics. In handball, it is possible to have a reliable estimate of anthropometric measurements, physical and physiological performances. PMID:22942992

  18. AeroCom INSITU Project: Comparison of Aerosol Optical Properties from In-situ Surface Measurements and Model Simulations

    NASA Astrophysics Data System (ADS)

    Schmeisser, L.; Andrews, E.; Schulz, M.; Fiebig, M.; Zhang, K.; Randles, C. A.; Myhre, G.; Chin, M.; Stier, P.; Takemura, T.; Krol, M. C.; Bian, H.; Skeie, R. B.; da Silva, A. M., Jr.; Kokkola, H.; Laakso, A.; Ghan, S.; Easter, R. C.

    2015-12-01

    AeroCom, an open international collaboration of scientists seeking to improve global aerosol models, recently initiated a project comparing model output to in-situ, surface-based measurements of aerosol optical properties. The model/measurement comparison project, called INSITU, aims to evaluate the performance of a suite of AeroCom aerosol models with site-specific observational data in order to inform iterative improvements to model aerosol modules. Surface in-situ data have the unique property of being traceable to physical standards, which is a big asset in accomplishing the overarching goal of bettering the accuracy of aerosol processes and predicative capability of global climate models. The INSITU project looks at how well models reproduce aerosol climatologies on a variety of time scales, aerosol characteristics and behaviors (e.g., aerosol persistence and the systematic relationships between aerosol optical properties), and aerosol trends. Though INSITU is a multi-year endeavor, preliminary phases of the analysis, using GOCART and other models participating in this AeroCom project, show substantial model biases in absorption and scattering coefficients compared to surface measurements, though the sign and magnitude of the bias varies with location and optical property. Spatial patterns in the biases highlight model weaknesses, e.g., the inability of models to properly simulate aerosol characteristics at sites with complex topography (see Figure 1). Additionally, differences in modeled and measured systematic variability of aerosol optical properties suggest that some models are not accurately capturing specific aerosol co-dependencies, for example, the tendency of in-situ surface single scattering albedo to decrease with decreasing aerosol extinction coefficient. This study elucidates specific problems with current aerosol models and suggests additional model runs and perturbations that could further evaluate the discrepancies between measured and modeled

  19. An overview of regional and local characteristics of aerosols in South Africa using satellite, ground, and modeling data

    PubMed Central

    Hersey, S. P.; Garland, R. M.; Crosbie, E.; Shingler, T.; Sorooshian, A.; Piketh, S.; Burger, R.

    2015-01-01

    We present a comprehensive overview of particulate air quality across the five major metropolitan areas of South Africa (Cape Town, Bloemfontein, Johannesburg and Tshwane (Gauteng Province), the Industrial Highveld Air Quality Priority Area (HVAPA), and Durban), based on a decadal (1 January 2000 to 31 December 2009) aerosol climatology from multiple satellite platforms and detailed analysis of ground-based data from 19 sites throughout Gauteng Province. Satellite analysis was based on aerosol optical depth (AOD) from MODIS Aqua and Terra (550 nm) and MISR (555 nm) platforms, Ångström Exponent (α) from MODIS Aqua (550/865 nm) and Terra (470/660 nm), ultraviolet aerosol index (UVAI) from TOMS, and results from the Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. At continentally influenced sites, AOD, α, and UVAI reach maxima (0.12–0.20, 1.0–1.8, and 1.0–1.2, respectively) during austral spring (September–October), coinciding with a period of enhanced dust generation and the maximum integrated intensity of close-proximity and subtropical fires identified by MODIS Fire Information for Resource Management System (FIRMS). Minima in AOD, α, and UVAI occur during winter. Results from ground monitoring indicate that low-income township sites experience by far the worst particulate air quality in South Africa, with seasonally averaged PM10 concentrations as much as 136 % higher in townships that in industrial areas. We report poor agreement between satellite and ground aerosol measurements, with maximum surface aerosol concentrations coinciding with minima in AOD, α, and UVAI. This result suggests that remotely sensed data are not an appropriate surrogate for ground air quality in metropolitan South Africa. PMID:26312061

  20. An overview of regional and local characteristics of aerosols in South Africa using satellite, ground, and modeling data

    NASA Astrophysics Data System (ADS)

    Hersey, S. P.; Garland, R. M.; Crosbie, E.; Shingler, T.; Sorooshian, A.; Piketh, S.; Burger, R.

    2015-04-01

    We present a comprehensive overview of particulate air quality across the five major metropolitan areas of South Africa (Cape Town, Bloemfontein, Johannesburg and Tshwane (Gauteng Province), the Industrial Highveld Air Quality Priority Area (HVAPA), and Durban), based on a decadal (1 January 2000 to 31 December 2009) aerosol climatology from multiple satellite platforms and detailed analysis of ground-based data from 19 sites throughout Gauteng Province. Satellite analysis was based on aerosol optical depth (AOD) from MODIS Aqua and Terra (550 nm) and MISR (555 nm) platforms, Ångström Exponent (α) from MODIS Aqua (550/865 nm) and Terra (470/660 nm), ultraviolet aerosol index (UVAI) from TOMS, and results from the Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. At continentally influenced sites, AOD, α, and UVAI reach maxima (0.12-0.20, 1.0-1.8, and 1.0-1.2, respectively) during austral spring (September-October), coinciding with a period of enhanced dust generation and the maximum integrated intensity of close-proximity and subtropical fires identified by MODIS Fire Information for Resource Management System (FIRMS). Minima in AOD, α, and UVAI occur during winter. Results from ground monitoring indicate that low-income township sites experience by far the worst particulate air quality in South Africa, with seasonally averaged PM10 concentrations as much as 136% higher in townships that in industrial areas. We report poor agreement between satellite and ground aerosol measurements, with maximum surface aerosol concentrations coinciding with minima in AOD, α, and UVAI. This result suggests that remotely sensed data are not an appropriate surrogate for ground air quality in metropolitan South Africa.

  1. Measurement of the physical properties of aerosols in a fullerene factory for inhalation exposure assessment.

    PubMed

    Fujitani, Yuji; Kobayashi, Takahiro; Arashidani, Keiichi; Kunugita, Naoki; Suemura, Kouji

    2008-06-01

    Assessment of human exposure is important for the elucidation of potential health risks. However, there is little information available on particle number concentrations and number size distributions, including those of nanoparticles, in the working environments of factories producing engineered nanomaterials. The authors used a scanning mobility particle sizer and an optical particle counter to measure the particle number size distributions of particles ranging in diameter (D(p)) from 10 nm to >5000 nm in a fullerene factory and used scanning electron microscopy to examine the morphology of the particles. Comparisons of particle size distributions and morphology during non-work periods, during work periods, during an agitation process, and in the nearby outdoor air were conducted to identify the sources of the particles and to determine their physical properties. A modal diameter of 25 nm was found in the working area during the non-work period; this result was probably influenced by ingress of outdoor air. During the removal of fullerenes from a storage tank for bagging and/or weighing, the particle number concentration at D(p)<50 nm was no greater than that in the non-work period, but the concentration at D(p)>1000 nm was greater during the non-work period. When a vacuum cleaner was in use, the particle number concentration at D(p)<50 nm was greater than that during the non-work period, but the concentration at D(p)>1000 nm was no greater. Scanning electron microscopy revealed that the coarse particles emitted during bagging and/or weighing were aggregates/agglomerates of fullerenes; although origin of particles with D(p)<50 nm is unclear. PMID:18401789

  2. Chemical and physical processes controlling aerosol compositions during Asian dust in May, 2008

    NASA Astrophysics Data System (ADS)

    Park, I.; Lee, M.; Han, J.; Lee, G.; Han, J.; Lim, S.; Kim, J.

    2008-12-01

    Asian dust events took place on May 29-31, 2008, which was the latest dust event ever observed in the spring. To examine chemical and physical processes controlling compositions of Asian dust particles, PM10, PM2.5 and PM1.0 samples were collected using cyclone along with MOUDI (Micro Orifice Uniform Deposit Impactor) samples from May 29 to June 2, 2008. For these particles, water soluble ions, and elemental and organic carbons were analyzed. Also, the morphology and elemental composition were examined using SEM/EDX. When dust intensity reached the maximum, the mass concentrations of PM10, PM2.5 and PM1.0 were 299.68ug/m3, 42.35ug/m3, 19.01ug/m3, respectively. During that period, all ions except NH4+ showed the maximum concentration for PM10. Particularly, the concentrations of NO3- and Ca2+ were remarkably elevated to 7.83¥ìg/m3 and 2.76¥ìg/m3, respectively. In contrast, NH4+, SO42- and NO3- concentrations of PM2.5 and PM1.0 were the highest on May 29, which was a day before the maximum dust intensity. This elevated levels of NH4+, SO42- and NO3- concentrations suggested the mixed plume of pollutants and dust particles on 29 May. For MOUDI samples, Ca2+ concentration were relatively uniform through the whole size range during the maximum dust intensity (30 May). In the following day, Ca2+ and NO3- concentrations increased noticeably at 0.1~0.18um. Sulfate concentrations were decreased during dust event. Detailed discussion will be presented in the meeting.

  3. Influence of the micro-physical properties of the aerosol on the atmospheric correction of OLI data acquired over desert area

    NASA Astrophysics Data System (ADS)

    Manzo, Ciro; Bassani, Cristiana

    2016-04-01

    This paper focuses on the evaluation of surface reflectance obtained by different atmospheric correction algorithms of the Landsat 8 OLI data considering or not the micro-physical properties of the aerosol when images are acquired in desert area located in South-West of Nile delta. The atmospheric correction of remote sensing data was shown to be sensitive to the aerosol micro-physical properties, as reported in Bassani et al., 2012. In particular, the role of the aerosol micro-physical properties on the accuracy of the atmospheric correction of remote sensing data was investigated [Bassani et al., 2015; Tirelli et al., 2015]. In this work, the OLI surface reflectance was retrieved by the developed OLI@CRI (OLI ATmospherically Corrected Reflectance Imagery) physically-based atmospheric correction which considers the aerosol micro-physical properties available from the two AERONET stations [Holben et al., 1998] close to the study area (El_Farafra and Cairo_EMA_2). The OLI@CRI algorithm is based on 6SV radiative transfer model, last generation of the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) radiative transfer code [Kotchenova et al., 2007; Vermote et al., 1997], specifically developed for Landsat 8 OLI data. The OLI reflectance obtained by the OLI@CRI was compared with reflectance obtained by other atmospheric correction algorithms which do not consider micro-physical properties of aerosol (DOS) or take on aerosol standard models (FLAASH, implemented in ENVI software). The accuracy of the surface reflectance retrieved by different algorithms were calculated by comparing the spatially resampled OLI images with the MODIS surface reflectance products. Finally, specific image processing was applied to the OLI reflectance images in order to compare remote sensing products obtained for same scene. The results highlight the influence of the physical characterization of aerosol on the OLI data improving the retrieved atmospherically corrected

  4. Sensitivity of clear-sky direct radiative effect of the aerosol to micro-physical properties by using 6SV radiative transfer model: preliminary results

    NASA Astrophysics Data System (ADS)

    Bassani, Cristiana; Tirelli, Cecilia; Manzo, Ciro; Pietrodangelo, Adriana; Curci, Gabriele

    2015-04-01

    The aerosol micro-physical properties are crucial to analyze their radiative impact on the Earth's radiation budget [IPCC, 2007]. The 6SV model, last generation of the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) radiative transfer code [Kotchenova et al., 2007; Vermote et al., 1997] has been used to perform physically-based atmospheric correction of hyperspectral airborne and aircraft remote sensing data [Vermote et al., 2009; Bassani et al. 2010; Tirelli et al., 2014]. The atmospheric correction of hyperspectral data has been shown to be sensitive to the aerosol micro-physical properties, as reported in Bassani et al., 2012. The role of the aerosol micro-physical properties on the accuracy of the atmospheric correction of hyperspectral data acquired over water and land targets is investigated within the framework of CLAM-PHYM (Coasts and Lake Assessment and Monitoring by PRISMA HYperspectral Mission) and PRIMES (Synergistic use of PRISMA products with high resolution meteo-chemical simulations and their validation on ground and from satellite) projects, both funded by Italian Space Agency (ASI). In this work, the results of the radiative field of the Earth/Atmosphere coupled system simulated by using 6SV during the atmospheric correction of hyperspectral data are presented. The analysis of the clear-sky direct radiative effect is performed considering the aerosol micro-physical properties used to define the aerosol model during the atmospheric correction process. In particular, the AERONET [Holben et al., 1998] and FLEXAOD [Curci et al., 2014] micro-physical properties are used for each image to evaluate the contribution of the size distribution and refractive index of the aerosol type on the surface reflectance and on the direct radiative forcing. The results highlight the potential of the hyperspectral remote sensing data for atmospheric studies as well as for environmental studies. Currently, the future hyperspectral missions, such as the

  5. Modeling of growth and evaporation effects on the extinction of 1.0-micron solar radiation traversing stratospheric sulfuric acid aerosols

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Deepak, A.

    1981-01-01

    The effects of growth and evaporation of stratospheric sulfuric acid aerosols on the extinction of solar radiation traversing such an aerosol medium are reported for the case of 1.0-micron solar radiation. Modeling results show that aerosol extinction is not very sensitive to the change of ambient water vapor concentration, but is sensitive to ambient temperature changes, especially at low ambient temperatures and high ambient water vapor concentration. A clarification is given of the effects of initial aerosol size distribution and composition on the change of aerosol extinction due to growth and evaporation processes. It is shown that experiments designed to observe solar radiation extinction of aerosols may also be applied to the determination of observed changes in aerosol optical properties, environmental parameters, or the physical and optical characteristics of sulfate aerosols.

  6. Application of laser light scattering for determination of the border aerosol-air in a specialized physical laboratory setup

    NASA Astrophysics Data System (ADS)

    Damov, K. S.; Iliev, M. T.

    2016-02-01

    The current article examines the application of laser light scattering in a specialized laboratory setup. It is used for determination of the kinematic viscosity and mass density of Aerodispersed Systems formed in Limited Volume (High Concentration Aerosols) by the method of free flow out. The measurement chamber is first filled with the investigated aerosol. After a predetermined delay time the aerosol is allowed to flow out through a calibrated pipe with fixed size located few centimetres above the chamber's bottom. The lowering of the upper border aerosol-air is continuously scanned using a laser beam directed along the axis of the cylindrical chamber. The kinematic viscosity and mass density of the investigated aerosol phase are calculated by formulas obtained by the authors. The suggested application of laser light scattering led to higher accuracy of the determination the position of aerosol-air border, thence the certainty of this method. This improvement allowed the use of computer controlled optoelectronic setting. The use of laser light scattering significantly improves the method for determination of the kinematic viscosity and mass density of Aerodispersed Systems formed in Limited Volume.

  7. Characteristics of Urban Sidewalks/Streets and Objectively Measured Physical Activity

    PubMed Central

    Heinrich, Katie M.; Poston, Walker S.C.; Hyder, Melissa; Pyle, Sara

    2007-01-01

    Several studies have found significant relationships between environmental characteristics (e.g., number of destinations, aesthetics) and physical activity. While a few of these studies verified that the physical activities assessed were performed in the environments examined, none have done this in an urban, neighborhood setting. This information will help efforts to inform policy decisions regarding the design of more “physically active” communities. Fourteen environmental characteristics of 60, 305-m-long segments, located in an urban, residential setting, were directly measured using standardized procedures. The number of individuals walking, jogging, and biking in the segments was assessed using an observation technique. The segments were heterogeneous with regards to several of the environmental characteristics. A total of 473 individuals were seen walking, bicycling, or jogging in the segments during 3,600 min of observation (60 min/segment). Of the 473 seen, 315 were walking, 116 bicycling, and 42 jogging. A greater number of individuals were seen walking in segments with more traffic, sidewalk defects, graffiti, and litter and less desirable property aesthetics. Only one environmental characteristic was associated with bicycling and none were significantly related with jogging. This study provides further evidence that environmental characteristics and walking are related. It also adds new information regarding the importance of scale (e.g., micro, macro) and how some environmental characteristics of urban, residential sidewalks and streets relate to physical activity. PMID:18161026

  8. Characteristics of urban sidewalks/streets and objectively measured physical activity.

    PubMed

    Suminski, Richard R; Heinrich, Katie M; Poston, Walker S C; Hyder, Melissa; Pyle, Sara

    2008-03-01

    Several studies have found significant relationships between environmental characteristics (e.g., number of destinations, aesthetics) and physical activity. While a few of these studies verified that the physical activities assessed were performed in the environments examined, none have done this in an urban, neighborhood setting. This information will help efforts to inform policy decisions regarding the design of more "physically active" communities. Fourteen environmental characteristics of 60, 305-m-long segments, located in an urban, residential setting, were directly measured using standardized procedures. The number of individuals walking, jogging, and biking in the segments was assessed using an observation technique. The segments were heterogeneous with regards to several of the environmental characteristics. A total of 473 individuals were seen walking, bicycling, or jogging in the segments during 3,600 min of observation (60 min/segment). Of the 473 seen, 315 were walking, 116 bicycling, and 42 jogging. A greater number of individuals were seen walking in segments with more traffic, sidewalk defects, graffiti, and litter and less desirable property aesthetics. Only one environmental characteristic was associated with bicycling and none were significantly related with jogging. This study provides further evidence that environmental characteristics and walking are related. It also adds new information regarding the importance of scale (e.g., micro, macro) and how some environmental characteristics of urban, residential sidewalks and streets relate to physical activity. PMID:18161026

  9. Inductively coupled plasma spectrometry: Noise characteristics of aerosols, application of generalized standard additions method, and Mach disk as an emission source

    SciTech Connect

    Shen, Luan

    1995-10-06

    This dissertation is focused on three problem areas in the performance of inductively coupled plasma (ICP) source. The noise characteristics of aerosols produced by ICP nebulizers are investigated. A laser beam is scattered by aerosol and detected by a photomultiplier tube and the noise amplitude spectrum of the scattered radiation is measured by a spectrum analyzer. Discrete frequency noise in the aerosol generated by a Meinhard nebulizer or a direct injection nebulizer is primarily caused by pulsation in the liquid flow from the pump. A Scott-type spray chamber suppresses white noise, while a conical, straight-pass spray chamber enhances white noise, relative to the noise seen from the primary aerosol. Simultaneous correction for both spectral interferences and matrix effects in ICP atomic emission spectrometry (AES) can be accomplished by using the generalized standard additions method (GSAM). Results obtained with the application of the GSAM to the Perkin-Elmer Optima 3000 ICP atomic emission spectrometer are presented. The echelle-based polychromator with segmented-array charge-coupled device detectors enables the direct, visual examination of the overlapping lines Cd (1) 228.802 nm and As (1) 228.812 nm. The slit translation capability allows a large number of data points to be sampled, therefore, the advantage of noise averaging is gained. An ICP is extracted into a small quartz vacuum chamber through a sampling orifice in a water-cooled copper plate. Optical emission from the Mach disk region is measured with a new type of echelle spectrometer equipped with two segmented-array charge-coupled-device detectors, with an effort to improve the detection limits for simultaneous multielement analysis by ICP-AES.

  10. Chemical, physical and radiative properties of atmospheric aerosols measured at Mt. Lulin Atmospheric Background Station (LABS) in East Asia during biomass burning seasons (Invited)

    NASA Astrophysics Data System (ADS)

    Lin, N.; Lee, C.; Wang, S.; Chuang, M.; Chia, E.; Andrews, E.; Ogren, J. A.; Lin, J.; Hung, H.; Hsiao, T.; Liang, S.

    2013-12-01

    This paper presents the chemical, physical and radiative properties of atmospheric aerosols measured at the Lulin Atmospheric Background Station (LABS) which is located at Mt. Lulin (2,862 m MSL; 23o 28'07"N, 120o52'25"E) in central Taiwan, East Asia, and has been operated since 13 April, 2006. LABS is unique because its location and altitude enhances the global network of GAW (Global Atmosphere Watch) in the Southeast Asian region, where no high-elevation baseline station is available. Our site is located between the GAW Waliguan station (3,810 m) on the Tibetan plateau and the Mauna Loa Observatory (3,397m) in Hawaii. We will particularly focus on the results obtained during the spring season, when biomass burning activities prevail in northern Southeast Asia. Chemical characterization of fine and coarse aerosol particles, including water-soluble ions, organic and elemental carbon, and trace elements, will be presented. Aerosol optical properties, including scattering, absorption, extinction, single scattering albedo, Ångström exponent, and aerosol optical depth, as well as the derived radiative forcing efficiency, will be discussed. Results of cloud condensation nuclei measurements, made intermittently, will also be presented. Trajectory studies indicate that this site experiences a variety of air masses originating from contaminated and clean source regions, giving a distinctive contrast of atmospheric changes. To summarize the results, the maximum values (and monthly means) of these chemical, physical and radiative parameters generally occurred during spring time, especially in March, corresponding to prevailing biomass burning activities in SE Asia. Besides, LABS is also one of the supersites during the 2010-2013 spring campaigns of the Seven South East Asian Studies (7-SEAS) for studying the impact of biomass burning on cloud, atmospheric radiation, hydrological cycle, and regional climate over Southeast Asian region. Results of source (northern Thailand

  11. Molecular characteristics of urban organic aerosols from Nanjing: a case study of A mega-city in China.

    PubMed

    Wang, Gehui; Kawamura, Kimitaka

    2005-10-01

    Over 90 organic species have been determined in fine aerosols (PM2.5) collected during the summer and winter in Nanjing, a typical mega-city in China, using gas chromatography-mass spectrometry. The organic compounds detected were apportioned to four emission sources (i.e., plant emission, fossil fuel combustion, biomass burning, and soil resuspension) and secondary oxidation products. The most abundant classes of compounds are fatty acids, followed by sugars, dicarboxylic acids excluding oxalic and malonic acids, and n-alkanes, while alcohols, polyols/polyacids and lignin/sterols are less abundant. Total amounts of the seven classes of compounds were on average 938 ng m(-3) in the summer and 1301 ng m(-3) in the winter, respectively, contributing 0.26-1.96% of particle mass (PM2.5). In the summer, n-alkanes were heavily enhanced by vegetation emissions with a maximum carbon number (Cmax) at C29, whereas they were dominated by emissions from fossil fuels combustion with a Cmax at C22/ C23 in the winter. Concentrations of unsaturated fatty acids were lower in the summer than in the winter, being consistent with enhanced photooxidation of unsaturated fatty acids in the summer. Concentrations of dicarboxylic acids for the summer aerosols were much higher in the daytime than in the nighttime, indicating increased photochemical production in the daytime. In the summer, plant emissions were the most significant source of organic aerosols, contributing more than 33% of total compound mass (TCM), followed by fossil fuel combustion or secondary oxidation. In contrast, fossil fuel combustion was the dominant source of winter organic aerosols, contributing more than 51% of TCM, followed by plant emissions and secondary oxidation products. The quantitative results on sugars and lignin pyrolysis products further suggested that biomass burning and soil resuspension are also significant sources of urban organic aerosols. PMID:16245812

  12. Thermogravimetric characteristics of water-soluble organic matter from atmospheric aerosols collected in a rural-coastal area

    NASA Astrophysics Data System (ADS)

    Duarte, Regina M. B. O.; Duarte, Armando C.

    The influence of chemical composition on the thermal degradation behaviour of water-soluble organic compounds (WSOC) from fine atmospheric aerosols collected over a period of 12 months was investigated by using thermogravimetric (TG) analysis. The obtained results were further compared to those of Suwannee River Humic Acid (SRHA) and Fulvic Acid (SRFA) standards, which were obtained from the International Humic Substances Society (IHSS). Prior to the TG analyses, the WSOC samples were separated into hydrophobic acids and hydrophilic acids fractions by using a XAD-8/XAD-4 isolation procedure. The data reported in this study were illustrative of the very complex nature of aerosol WSOC hydrophobic acids samples (three to six peaks of thermal degradation) in comparison to that of SRHA and SRFA standards (two degradation peaks). A pseudo-first order mathematical approach was applied to estimate the apparent activation energy of the different multi-step degradation regions. It was found that the degradation processes of the SRHA and SRFA standards occurred with lower apparent activation energies than those obtained for the aerosol WSOC hydrophobic acids samples, although these latter samples appear to exhibit the most thermally labile structural component. The WSOC hydrophobic acids showed a trend towards high apparent activation energies at high temperatures, thus suggesting the decomposition of very stable structural units with relatively strong bond energies above ca. 460 °C. The thermal profiles presented in this study are unique in showing the annual evolution of the thermal-oxidative properties of the fine aerosol WSOC hydrophobic acids samples, and in providing important supplementary information on the structural stability of the bulk aerosol WSOC.

  13. Aerosol temporal characteristics and its impact on shortwave radiative forcing at a location in the northeast of India

    NASA Astrophysics Data System (ADS)

    Pathak, Binita; Kalita, Gayatry; Bhuyan, K.; Bhuyan, P. K.; Moorthy, K. Krishna

    2010-10-01

    Measurements of aerosol optical depth (AOD) and mass concentration of composite and black carbon (BC) aerosols made with collocated instruments over Dibrugarh in Northeast India are used to estimate the aerosol radiative forcing for the period June 2008 to May 2009. AOD shows seasonal variation with maximum in premonsoon (0.69 ± 0.13 at 500 nm in March 2009) and minimum in the retreating monsoon (0.08 ± 0.01 at 500 nm in October 2008). Ångström coefficients α and β are highest in monsoon and premonsoon season and are lowest in premonsoon and retreating monsoon, respectively. The size segregated mass concentration is minimum in the monsoon season for all the three modes nucleation, accumulation, and coarse and maximum in winter for accumulation and coarse and in premonsoon for nucleation mode. The BC mass concentration is highest 16.3 ± 1.4 μg m-3 in winter and lowest 3.4 ± 0.9 μg m-3 in monsoon. The estimated aerosol radiative forcing of the atmosphere, using Optical Properties of Aerosols and Clouds (OPAC) outputs as inputs for Santa Barbara Discrete Ordinate Atmospheric Radiative Transfer (SBDART), is maximum in premonsoon followed by that in winter and minimum in retreating monsoon. Negative forcing is observed at the surface, whereas the top of the atmosphere (TOA) forcing is nearly zero in retreating monsoon and is negative in rest of the seasons. The forcing efficiency and heating rate were highest during winter and premonsoon, respectively.

  14. Design considerations and performance characteristics of AirSentinel: a new UV-LIF bio-aerosol threat detection trigger

    NASA Astrophysics Data System (ADS)

    DeFreez, Richard; Merrill, Ezra; Albanna, Sam; Davis, Bert; Call, Charles

    2005-10-01

    AirSentinel® is a new low cost, compact ultraviolet-based light induced fluorescence (UV-LIF) bio-aerosol threat detection trigger. Earlier UV-LIF triggers, for example, FLAPS, BARTS, BAWS, Bioni, and BioLert, have used UV laser sources to induce fluorescence of biological aerosols. Two recent developments from the DARPA MTO SUVOS program, BAST and TAC-BIO, use UV LEDs for the same purpose, thereby broadening the term UV-LIF to mean laser or LED induced autofluorescence. All of these earlier triggers interrogate aerosols on a particle-by-particle basis on- the-fly. The major trade-off for these instruments is cost, size, and complexity versus counting efficiency (probability of detection) with the lower size end of the respirable range being most difficult to detect. AirSentinel® employs a different approach to UV-LIF detection: aerosol concentration by collection on a surface, surface interrogation, and surface rejuvenation prior to repeated concentration and interrogation cycles. Aerosol particle concentration via impaction on a surface addresses the issue of small particle counting efficiency since the fluorescence from the sum of the particles is the sum of the fluorescence signals from the collected particles, typically hundreds or thousands in number. Surface interrogation for a LIF signal is accomplished by illumination with a 280 nm and/or a 365 nm LED. As expected, test results show better relative detection performance using 280 nm excitation LEDs for bio-toxin simulants and somewhat better performance at 365 nm for standard Bacillus globigii spore targets. AirSentinel® beta technology is currently in long term testing in a number of public and other government buildings.

  15. Aerosol Indirect Effects on Cirrus Clouds in Global Aerosol-Climate Models

    NASA Astrophysics Data System (ADS)

    Liu, X.; Zhang, K.; Wang, Y.; Neubauer, D.; Lohmann, U.; Ferrachat, S.; Zhou, C.; Penner, J.; Barahona, D.; Shi, X.

    2015-12-01

    Cirrus clouds play an important role in regulating the Earth's radiative budget and water vapor distribution in the upper troposphere. Aerosols can act as solution droplets or ice nuclei that promote ice nucleation in cirrus clouds. Anthropogenic emissions from fossil fuel and biomass burning activities have substantially perturbed and enhanced concentrations of aerosol particles in the atmosphere. Global aerosol-climate models (GCMs) have now been used to quantify the radiative forcing and effects of aerosols on cirrus clouds (IPCC AR5). However, the estimate uncertainty is very large due to the different representation of ice cloud formation and evolution processes in GCMs. In addition, large discrepancies have been found between model simulations in terms of the spatial distribution of ice-nucleating aerosols, relative humidity, and temperature fluctuations, which contribute to different estimates of the aerosol indirect effect through cirrus clouds. In this presentation, four GCMs with the start-of-the art representations of cloud microphysics and aerosol-cloud interactions are used to estimate the aerosol indirect effects on cirrus clouds and to identify the causes of the discrepancies. The estimated global and annual mean anthropogenic aerosol indirect effect through cirrus clouds ranges from 0.1 W m-2 to 0.3 W m-2 in terms of the top-of-the-atmosphere (TOA) net radiation flux, and 0.5-0.6 W m-2 for the TOA longwave flux. Despite the good agreement on global mean, large discrepancies are found at the regional scale. The physics behind the aerosol indirect effect is dramatically different. Our analysis suggests that burden of ice-nucleating aerosols in the upper troposphere, ice nucleation frequency, and relative role of ice formation processes (i.e., homogeneous versus heterogeneous nucleation) play key roles in determining the characteristics of the simulated aerosol indirect effects. In addition to the indirect effect estimate, we also use field campaign

  16. Aerosol-Cloud-Precipitation Interactions in the Climate System

    NASA Astrophysics Data System (ADS)

    Andreae, M. O.

    2015-12-01

    Aerosols serve as cloud condensation nuclei (CCN) and thus have a powerful effect on cloud properties. Increased aerosol concentrations resulting from pollution lead to higher cloud droplet concentrations, but smaller droplet sizes. This in turn affects the physical processes inside clouds that lead to the initiation of precipitation. Depending on a number of factors, including aerosol composition, atmospheric stability, and cloud water content, increasing CCN concentrations may either decrease or increase rainfall. In convective clouds, early rain formation is suppressed, which makes more water and energy available to rise higher in the atmosphere and form ice particles. This may invigorate the dynamics of convection, encourage the formation of hail and lightning, and enhance the transport of materials to the upper troposphere. In turn, cloud processing also affects the concentrations, composition, and distribution of atmospheric aerosols. In order to understand and quantify the effects of air pollution on climate, and precipitation in particular, knowledge of natural abundance and characteristics of aerosols is as essential as the observation of perturbed conditions. I will present recent advances in the conceptual understanding of aerosol-precipitation interactions, as well as results of measurements on aerosol and cloud characteristics in pristine and polluted conditions.

  17. Quantitative physical and handling characteristics of novel antibacterial braided silk suture materials.

    PubMed

    Chen, Xiaojie; Hou, Dandan; Tang, Xiaoqi; Wang, Lu

    2015-10-01

    Surgical braided silk sutures have been widely used because these materials exhibit good handling characteristics, ease of use, and ideal knot security. However, surgical silk sutures likely cause surgical site infections because these sutures are composed of natural protein materials with a braided structure. As such, antibacterial silk sutures for clinical wound closure should be developed. Braided silk suture could be treated and modified with antibacterial agent, provided that excellent physical and handling characteristics of this material should maximize maintained. This study aimed to quantitatively investigate the effect of antibacterial treatment with different parameters on physical and handling characteristics of novel antibacterial braided silk sutures. Physical and handling characteristics, including appearance, knot-pull tensile strength, pullout friction resistance, tissue drag friction resistance, and bending stiffness, were evaluated. After physical and handling tests were conducted, images showed morphological characteristics were obtained and evaluated to investigate the relationship between antibacterial treatment and physical and handling properties. Results showed that suture diameter increased and reached the nearest thick size specification; knot-pull tensile strength decreased but remained higher than the standard value by at least 40.73%. Fracture asynchronism during knot-pull tensile strength test suggested that the fineness ratio of shell and core strands may enhance knot-pull tensile strength. Static and dynamic frictions of suture-to-suture friction behavior were slightly affected by antibacterial treatment, and changed to less than 16.07% and 32.77%, respectively. Suture-to-tissue friction and bending stiffness increased by approximately 50%; the bending stiffness of the proposed suture remained efficient compared with that of synthetic sutures. Therefore, good physical and handling characteristics can be maintained by selecting

  18. Influences of external vs. core-shell mixing on aerosol optical properties at various relative humidities.

    PubMed

    Ramachandran, S; Srivastava, Rohit

    2013-05-01

    aerosol (core)-shell (BC) when compared to their external mixture, while the SSA for maritime aerosols does not vary significantly for different mixing scenarios because of the dominance of sea salt aerosols. Thus, these results confirm that aerosol mixing can modify the physical and optical characteristics of aerosols, which vary as a function of relative humidity. These calculations will be useful in parameterising the effect of core-shell vs. external mixing of aerosols in global climate models, and in the evaluation of aerosol radiative effects. PMID:23563501

  19. The study of physics and safety characteristics for In-Hospital Neutron Irradiator (IHNI)

    SciTech Connect

    Ke Guotu; Sun Zhiyong; Shen Feng; Liu Tiancai; Zheng lv

    2008-07-15

    The IHNI is designed with low-enrichment {sup 235}U (LEU) for Boron Neutron Capture Therapy (BNCT) based on Miniature Neutron Source Reactor (MNSR). The IHNI, operated with thermal power 30kW, is an under-moderated reactor of pool-tank type, and UO{sub 2} as fuel, light water as coolant and moderator, and metallic beryllium as reflector. The paper gives the physics and safety characteristics of IHNI. The physics characteristics include those parameters of the criticality and the beam port used for BNCT. The safety characteristics compare the safety parameters between reactor core of LEU and HEU. The result shows that LEU could meet the requirements of criticality and flux at exit of each beam. Furthermore, the better safety characteristics could approach by adopting the LEU in comparison with HEU. (author)

  20. Physical characteristics of stream subbasins in the Cannon River Basin, southern Minnesota

    USGS Publications Warehouse

    Sanocki, Christopher A.; Winterstein, Thomas A.

    2000-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Cannon River Basin, located in southeastern Minnesota, are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and marsh, the main-channel length, and the main-channel slope. Stream sites include outlets of subbasins of at least 5 square miles, and locations of U.S. Geological Survey high-flow, and continuous-record gaging stations.

  1. Physical characteristics of stream subbasins in the Cottonwood River basin, southwestern Minnesota

    USGS Publications Warehouse

    Sanocki, C.A.

    1995-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected points on streams in the Cottonwood River Basin, located in southwestern Minnesota, are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slop?. The points on the stream include outlets of subbasins of at least 5 square miles, outlets of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  2. Physical Characteristics of Stream Subbasins in the Redeye (Leaf) River Basin, Central Minnesota

    USGS Publications Warehouse

    Sanocki, Christopher A.; Fischer, Brian C.

    2000-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Redeye (Leaf) River Basin, located in central Minnesota, are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slope. Stream sites include outlets of subbasins of at least 5 square miles, and locations of U.S. Geological Survey high-flow, and continuous-record gaging stations.

  3. Generation and physical characteristics of the Landsat 1 and 2 MSS computer compatible tapes

    NASA Technical Reports Server (NTRS)

    Thomas, V. L.

    1975-01-01

    The generation and format is discussed of the Landsat 1 and 2 system corrected multispectral scanner computer compatible tapes. Included in the discussion are the spacecraft sensors, scene characteristics, the transmission of data, and the conversion of the data to computer compatible tapes at the NASA Data Processing Facility. Geometric and radiometric corrections, tape formats, and the physical characteristics of the tape are also described.

  4. Yak dung combustion aerosols in the Tibetan Plateau: Chemical characteristics and influence on the local atmospheric environment

    NASA Astrophysics Data System (ADS)

    Chen, Pengfei; Kang, Shichang; Bai, Jiankun; Sillanpää, Mika; Li, Chaoliu

    2015-04-01

    The study of the source areas of atmospheric pollutants in the Tibetan Plateau (TP) - one of the most remote regions in the world - has raised a great deal of concern. It is generally considered that the majority of pollutants in this region are transported from outside the TP. This research investigated the water soluble elements and carbonaceous matter from aerosols emitted from yak dung combustion by local residents and re-analyzed previous OC and BC data at Nam Co - a remote area of the TP. The compositions of the water soluble elements of the studied aerosols were similar to those in precipitation and snow samples of the region under investigation. Some heavy metal elements (e.g. Cd and As) even had higher enrichment factor (EF) values (1793 and 2355, respectively) compared to those in precipitation and snow samples, implying that previously reported high EF values for precipitation and snow did not completely reflect the long-range transported pollutants from outside the TP. Accordingly, the contributions of local sources needed to be considered. Organic carbon (OC) and black carbon (BC) accounted for 55.2% and 3.63% of the studied aerosol, respectively. The OC/BC ratio of the studied aerosols was close to the corresponding value for the outdoor aerosols, further indicating the influence of local sources on the atmosphere of Nam Co. It was proposed that air masses from South Asia cause high BC concentrations in the Nam Co region. It was, however, discovered that air masses from the TP itself also induce high BC concentrations, suggesting that not all the BC of Nam Co was transported from South Asia. Therefore, it is proposed that pollutants of atmospheric aerosols of the Nam Co region were derived from a variety of sources from both the TP and outside. In other words, the influence of yak dung burning by local residents on the atmosphere of the TP cannot be overlooked. Correspondingly, long-range transported pollutants can penetrate into the inland TP only

  5. Characteristics of aerosols and mass closure study at two WMO GAW regional background stations in eastern China

    NASA Astrophysics Data System (ADS)

    Yan, Peng; Zhang, Renjian; Huan, Ning; Zhou, Xiuji; Zhang, Yangmei; Zhou, Huaigang; Zhang, Leiming

    2012-12-01

    In the summer and winter of 2004 and 2005, size-segregated atmospheric aerosols were sampled with modified Andersen KA200 Multi-stage impactor at two regional background stations in the eastern China, the Shangdianzi station (SDZ) in the suburb of Beijing and the Lin'An station (LA) in the Yangtze river delta region, both are WMO Global Atmospheric Watch station, which represent the regional background of air pollutions of the two rapid developing economical zone of China, the Yangtze River Delta region (YRD) and Beijing-Tianjin region. The aerosol mass size distributions, ionic compositions, organic and elemental carbon (OC and EC), and elemental components were analyzed. The mass concentrations for TSP (total suspend particle), PM11 (aerodynamic diameter less than 11 μm), and PM2.1 (aerodynamic diameter less than 2.1 μm) at both sites showed obviously different between the winter and summer, with higher mass concentrations measured in the winter time. All seasonal mean mass concentrations of PM2.1 accounted for over 50% of PM11 at both sites. The aerosol mass closure study indicated that the total mass concentration reconstructed from the aerosol chemical composition agreed well with the measured gravimetric mass at the two stations. The fine aerosol particles at the two stations were composed mainly of sulfate and organic matter. In the summer, more than half of the PM2.1 mass was sulfate, suggesting a dominant contribution of secondary aerosol to the fine particles in these two regions. In the winter, the contribution of nitrate to the fine particles increased significantly due to the lower volatile losses under the cold weather. The proportions of soil type components in the PM2.1 showed similar magnitude in the winter and summer at Lin'An station but significant seasonal differences with higher fractions in the winter at Shangdianzi station. On average EC accounted for about 2%-6% of the fine particle mass (PM2.1) at both sites with proportionally lower EC

  6. Wintertime characteristics of aerosols at middle Indo-Gangetic Plain: Impacts of regional meteorology and long range transport

    NASA Astrophysics Data System (ADS)

    Kumar, M.; Tiwari, S.; Murari, V.; Singh, A. K.; Banerjee, T.

    2015-03-01

    To develop a coherent picture of possible origin of Asian aerosol, transport and meteorological interaction; wintertime aerosol (January, 1 to March, 31, 2014 (n = 90)) were measured in middle IGP in terms of aerosol mass loading, optical properties, altitudinal distributions and both high and low altitude transportation. Both space-borne passive (Aqua and Terra MODIS) and active sensor (CALIPSO-CALIOP) based measurements were concurrently used over the selected transect (25°10‧-25°19‧N and 82°54‧-83°4‧E). Exceptionally high aerosol mass loading was recorded for PM10 (233 ± 58.37 μg m-3) and PM2.5 (138 ± 47.12 μg m-3). Daily variations of PM2.5/PM10 persist in a range of 0.25-0.97 (mean = 0.60 ± 0.14; n = 90) and were in accordance to computed Angstrom exponent (0.078-1.407; mean: 1.002 ± 0.254) explaining concurrent contribution of both PM2.5 and PM10 for the region. Space borne (Aqua MODIS-AOD: 0.259-2.194) and ground based (MTP-AOD: 0.066-1.239) AODs revealed significant temporal variability and moderate association in terms of PM10 (MODIS-AOD: 0.46; MTP-AOD: 0.56) and PM2.5 (MODIS-AOD: 0.54; MTP-AOD: 0.39). Varying association of AOD and aerosol mass loading was also explained in terms of meteorological variables. CALIPSO altitude-orbit-cross-section profiles revealed presence of non-spherical coarse particulates (altitude: 1.2-5.4 km) and dominance of spherical fine particulates (altitude: 0.1-4.2 km). Contribution of trans-boundary aerosols transportation to mass loadings at middle IGP were recognized through lagrangian particle dispersion model, synoptic vector wind profiles at different geopotential heights and satellite images.

  7. 3D Monte Carlo simulation of solar radiance in the clear-sky and low-cloud atmosphere for retrieval of aerosol and cloud characteristics

    NASA Astrophysics Data System (ADS)

    Zhuravleva, Tatiana; Bedareva, Tatiana; Nasrtdinov, Ilmir

    As is well known, the spectral measurements of direct and diffuse solar radiation can be used to retrieve the optical and microphysical characteristics of atmospheric aerosol and clouds. Most methods of radiation calculations, which are used to solve the inverse problems, are implemented under the assumption of horizontal homogeneity of the atmosphere (clear-sky and overcast conditions). However, it is recognized that the 3D effects of clouds have a significant impact on the transfer of solar radiation in the atmosphere which can be the cause of errors in retrieval of aerosol and cloud properties. In this work, we present the algorithms of the Monte Carlo method for calculating the angular structure of diffuse radiation in the molecular-aerosol atmosphere and the appearance of isolated cloud. The simulation of radiative characteristics with specified spectral resolution is performed in spherical model of the atmosphere for the conditions of observations at the Earth’s surface and at the top of the atmosphere. Cloud is approximated by inverted paraboloid. The molecular absorption is accounted for on the basis of approximation of transmission function by short exponential series (k-distribution method). The specific features of the radiative transfer, caused by the 3D effects of clouds, are considered depending on cloud location in space and its sizes, sensing scheme, and illumination conditions. The simulation results of the brightness fields in the clear sky and in the appearance of isolated cloud are compared. This work was supported in part by the Russian Fund for Basic Research (through the grant no. 12-05-00169).

  8. Sources and characteristics of carbonaceous aerosols at Agra "World heritage site" and Delhi "capital city of India".

    PubMed

    Pipal, A S; Tiwari, S; Satsangi, P G; Taneja, Ajay; Bisht, D S; Srivastava, A K; Srivastava, M K

    2014-01-01

    Agra, one of the oldest cities "World Heritage site", and Delhi, the capital city of India are both located in the border of Indo-Gangetic Plains (IGP) and heavily loaded with atmospheric aerosols due to tourist place, anthropogenic activities, and its topography, respectively. Therefore, there is need for monitoring of atmospheric aerosols to perceive the scenario and effects of particles over northern part of India. The present study was carried out at Agra (AGR) as well as Delhi (DEL) during winter period from November 2011 to February 2012 of fine particulate (PM₂.₅: d < 2.5 μm) as well as associated carbonaceous aerosols. PM₂.₅ was collected at both places using medium volume air sampler (offline measurement) and analyzed for organic carbon (OC) and elemental carbon (EC). Also, simultaneously, black carbon (BC) was measured (online) at DEL. The average mass concentration of PM₂.₅ was 165.42 ± 119.46 μg m(-3) at AGR while at DEL it was 211.67 ± 41.94 μg m(-3) which is ~27% higher at DEL than AGR whereas the BC mass concentration was 10.60 μg m(-3). The PM₂.₅ was substantially higher than the annual standard stipulated by central pollution control board and United States Environmental Protection Agency standards. The average concentrations of OC and EC were 69.96 ± 34.42 and 9.53 ± 7.27 μm m(-3), respectively. Total carbon (TC) was 79.01 ± 38.98 μg m(-3) at AGR, while it was 50.11 ± 11.93 (OC), 10.67 ± 3.56 μg m(-3) (EC), and 60.78 ± 14.56 μg m(-3) (TC) at DEL. The OC/EC ratio was 13.75 at (AGR) and 5.45 at (DEL). The higher OC/EC ratio at Agra indicates that the formation of secondary organic aerosol which emitted from variable primary sources. Significant correlation between PM₂.₅ and its carbonaceous species were observed indicating similarity in sources at both sites. The average concentrations of secondary organic carbon (SOC) and primary organic carbon (POC) at AGR were 48.16 and 26

  9. Chemical characteristics of aerosol particles (PM2.5) at a site of Horqin Sand-land in northeast China.

    PubMed

    Shen, Zhen-xing; Cao, Jun-ji; Li, Xu-xiang; Wang, Ya-qiang; Jie, Dong-mei; Zhang, Xiao-ye

    2006-01-01

    The objective of this study was to characterize the mass concentration and chemical composition of aerosol particles (PM2.5) collected at Tongliao (Inner Mongolia Autonomous Region, China), a site in Horqin Sand-land in northeast China. During spring 2005, the mass concentration for PM2.5 was (126 +/- 71)microg/m3 in average. Five dust storm events were monitored with higher concentration of (255 +/- 77)microg/m3 in average than the non dusty days of (106 +/- 44)microg/m3. Concentrations for 20 elements were obtained by the PIXE method. Mass concentrations of Al, Mg, Si, K, Ca, Ti, Mn, and V, which increased with the PM2.5 concentration, were higher than the pollution elements (S, Cl, Zn, Ar, Se, Br, and Pb). Enrichment factor relative to crust material was also calculated, which showed dust trace elements were mainly from earth upper crust and pollution elements were dominated the anthropogenic aerosols. The Si/Al, Ca/Al, and Fe/Al ratios in PM2.5 samples at Tongliao were 4.07, 0.94, and 0.82, respectively, which were remarkably different with those on other source regions, such as "Western desert source region", "North desert source region" and central Asia source. Air mass back-trajectory analysis identified three kinds of general pathways were associated with the aerosol particle transport to Tongliao, but have the similar elemental ratios, implying that elemental signatures for dust aerosol from Horqin Sand-land were different with other regions. PMID:17078548

  10. Southeast Asian Summer Burning: A Micro Pulse Lidar Network Study of Aerosol Particle Physical Properties near Fires in Borneo and Sumatra

    NASA Astrophysics Data System (ADS)

    Lolli, S.; Welton, E. J.; Holben, B. N.; Campbell, J. R.

    2013-12-01

    In August and September 2012, as part of the continuing Seven South East Asian Studies (7-SEAS) project, three autonomous elastic-scattering 355 nm lidars were deployed by the NASA Micro Pulse Lidar Network (MPLNET) to Sumatra and Borneo, measuring the vertical profile of aerosol particle scattering during peak burning season. In coordination with the Aerosol Robotic Network (AERONET), a regional characterization of aerosol particle physical properties and distribution was performed. In addition to a permanent regional network site at Singapore, the three temporary sites established for this research include Jambi (Sumatra, Indonesia), Kuching (northwest Borneo, Malaysia) and Palangkaraya (south-central Borneo, Indonesia). In this paper, we discuss the mission and instruments, and introduce data products available to the community through the MPLNET online website. We further describe initial results of the study, including a contrast of mean vertical scattering profiles versus those observed near active fire sources at Jambi and Palangkaraya, and resolve longer-range particle evolution at receptor sites, like Kuching, that are most commonly 1-2 days downwind of larger fire complexes.

  11. The Role of Biographical Characteristics in Preservice Classroom Teachers' School Physical Activity Promotion Attitudes

    ERIC Educational Resources Information Center

    Webster, Collin A.; Monsma, Eva; Erwin, Heather E.

    2010-01-01

    Recommendations for increasing children's daily physical activity (PA) call on classroom teachers to assume an activist role at school. This study examined relationships among preservice classroom teachers' (PCT; n = 247) biographical characteristics, perceptions and attitudes regarding school PA promotion (SPAP). Results indicated participants…

  12. The Physical and Technical Characteristics of English Language Teaching Courseware in Malaysia

    ERIC Educational Resources Information Center

    Mukundan, Jayakaran; Nimehchisalem, Vahid; Sayadian, Sima

    2012-01-01

    The present paper reports the findings of a study that investigated the physical and technical characteristics of the English language teaching courseware in Malaysia. A randomly selected group of English language teachers in Malaysia (n = 200) were surveyed to evaluate the courseware. SPSS (18.0) was applied to analyze the data. The results…

  13. Physical Performance Characteristics of Assisted Living Residents and Risk for Adverse Health Outcomes

    ERIC Educational Resources Information Center

    Giuliani, Carol A.; Gruber-Baldini, Ann L.; Park, Nan S.; Schrodt, Lori A.; Rokoske, Franzi; Sloane, Philip D.; Zimmerman, Sheryl

    2008-01-01

    Purpose: Researchers know little about the physical performance ability of residential care/assisted living (RC/AL) residents and its relationship to adverse outcomes such as fracture, nursing home placement, functional decline, and death. The purposes of this article are to (a) describe the functional characteristics of RC/AL residents, (b)…

  14. Status of Physical Education Teachers Employed in Illinois Public Schools--Supply, Characteristics and Trends

    ERIC Educational Resources Information Center

    Razor, Jack E.; Arnold, Donald E.

    1975-01-01

    The study analyzes the extensiveness of the employment of physical education teachers in Illinois and identifies selected characteristics about the population which could prove beneficial in interpreting the supply situation to schools of education and other areas of the educational spectrum. (Editor/RK)

  15. Frequency of Use and Characteristics of People with Intellectual Disabilities Subject to Physical Interventions

    ERIC Educational Resources Information Center

    McGill, Peter; Murphy, Glynis; Kelly-Pike, Amanda

    2009-01-01

    Background: The use of physical intervention (PI) with people with intellectual disabilities continues to cause concern. This study sought to clarify the frequency and circumstances of PI use and gather data on the characteristics of individuals subject to PI. Method: Data on individuals subject to PI were gathered by postal questionnaire…

  16. Influence of disperse phase characteristics on stability, physical and antimicrobial properties of emulsions containing cinnamaldehyde

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cinnamaldehyde was delivered in emulsion form using Acetem 90-50K as a carrier and Tween 60 as emulsifier. Cinnamaldehyde interacted with Acetem 90-50K by forming H-bonds. The effect of disperse phase characteristics on storage stability, physical and antimicrobial properties was investigated. Stora...

  17. Pesticide occurrence in groundwater and the physical characteristics in association with these detections in Ireland.

    PubMed

    McManus, Sarah-Louise; Richards, Karl G; Grant, Jim; Mannix, Anthony; Coxon, Catherine E

    2014-11-01

    This study explores the associations of pesticide occurrence in groundwater to geological characteristics of the monitoring points (MPs) contributing area. Pesticide analyses were undertaken during a 2-year groundwater monitoring campaign which generated 845 samples. MCPA and mecoprop were the most frequently detected pesticides in groundwater. Each MP (n = 158) had a specifically delineated zone of contribution (ZOC) and the dominant physical characteristics present from nine national datasets were recorded for each ZOC. Associations between detections in groundwater and the dominant physical characteristic in each MPs ZOC tested were then statistically analyzed using Fisher's exact test, logistic regression, and multiple logistic regression. The original physical characteristic datasets used that were associated with detections in groundwater were the type of MP, aquifer type, and Quaternary deposit type. Logistic regression revealed that springs, regionally important aquifer types, aquifers with a karstic flow regime, and alkaline Quaternary deposits in existence above karst aquifers in a MP's ZOC were more likely to have a pesticide detection in groundwater. Multiple regression from this exploratory work showed some mutual dependency between soil association, aquifer type, and the Geological Survey of Ireland groundwater vulnerability map. The combination of national monitoring data and physical attribute datasets can be used to explore key areas where groundwater is more vulnerable to pesticide contamination. PMID:25195040

  18. RELATIONSHIP BETWEEN LUNG FUNCTION AND PHYSICAL CHARACTERISTICS IN YOUNG ADULT BLACK AND WHITE MALES AND FEMALES

    EPA Science Inventory

    The relationships of lung function to physical characteristics in young adults have not been adequately described for different gender-race groups in the United States. s part of a study of the effects of ozone exposure upon Black and White men and women, we measured lung volumes...

  19. Development of a Direct Observation Instrument to Measure Environmental Characteristics of Parks for Physical Activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study's purpose is to describe the development and evaluate the reliability (inter-observer agreement) and validity (rater agreement with a gold standard) of a direct observation instrument to assess park characteristics that may be related to physical activity. A direct observation instrument ...

  20. Impact of Policy Environment Characteristics on Physical Activity and Sedentary Behaviors of Children Attending Afterschool Programs

    ERIC Educational Resources Information Center

    Beets, Michael W.; Huberty, Jennifer; Beighle, Aaron; Moore, Justin B.; Webster, Collin; Ajja, Rahma; Weaver, Glenn

    2013-01-01

    State and national organizations recently developed policies focused on increasing physical activity (PA) in afterschool programs (ASPs). These policies emphasize "activity friendly" environment characteristics that, when present, should lead to higher levels of PA and reduce the amount of time children spend sedentary during an ASP. Currently,…

  1. Diagnostic opto-electronic system for measuring physical and biological characteristics of the skin in vivo

    NASA Astrophysics Data System (ADS)

    Makara, Ivanna V.; Kozhukhar, Oleksander T.; Komada, Pawel; Dussembayeva, Shynar

    2015-12-01

    Actuality development of optoelectronic rapid diagnostic system for measuring physical and biological characteristics of the skin in vivo with radiation of electromagnetic radiation in the optical range to obtain objective information on the spatial distribution of biochemical and morphological and anatomical components are different for state standards and pathology.

  2. Physical capsule and seed characteristics impact nutrient densities in cuphea seed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We quantified interrelationships between nutrient densities and their dependencies on weights and physical characteristics of capsules and seeds of indeterminate Cuphea plants subjected to no (GDD0) or to source-sink manipulation by removing the top 25% of plant foliage at 100 and 200 growing degree...

  3. Characteristics of physical activity programs in the Brazilian primary health care system.

    PubMed

    Gomes, Grace Angélica de Oliveira; Kokubun, Eduardo; Mieke, Grégore Iven; Ramos, Luiz Roberto; Pratt, Michael; Parra, Diana C; Simões, Eduardo; Florindo, Alex A; Bracco, Mario; Cruz, Danielle; Malta, Deborah; Lobelo, Felipe; Hallal, Pedro C

    2014-10-01

    The aim of this study was to describe the characteristics of programs that promote physical activity in the public primary care system by region of Brazil, subject to the presence or absence of multidisciplinary primary care teams (NASF). We conducted a cross sectional and population-based telephone survey of the health unit coordinators from 1,251 health care units. Coordinators were asked about the presence and characteristics of physical activity programs. Four out of ten health units reported having a physical activity intervention program, the most common involving walking groups. Most of the activities were performed in the morning, once or twice a week, and in sessions of 30 minutes or more. Physical education professionals were primarily responsible for directing the activities. Interventions occurred in the health unit itself or in adjacent community spaces. In general, these characteristics were similar between units with or without NASF, but varied substantially across regions. These findings will guide future physical activity policies and programs within primary care in Brazil. PMID:25388318

  4. Preliminary aerosol generator design studies

    NASA Technical Reports Server (NTRS)

    Stampfer, J. F., Jr.

    1976-01-01

    The design and construction of a prototype vaporization generator for highly dispersed sodium chloride aerosols is described. The aerosol generating system is to be used in the Science Simulator of the Cloud Physics Laboratory Project and as part of the Cloud Physics Laboratory payload to be flown on the shuttle/spacelab.

  5. [Characteristics of lipid peroxidation and markers of endogenous intoxication in monitoring physical loads during rower training].

    PubMed

    Statsenko, E A

    2011-01-01

    The objective of the present study was to estimate the informative value of characteristics of lipid peroxidation (LOP) and the level of middle molecular weight peptides (MWP) in the blood as indicators to be used for monitoring the training process in 37 rowers. Each athlete was examined in triplicate (a total of 90 observations). Coefficients of correlation between the above characteristics and the total duration of physical exercises performed during a one-month period were calculated for each of the five intensity categories. The relationship between the extent of training and the level of LOP end-products proved to be opposite to the relationship between the extent of training and the plasma MWP level. The latter parameter positively correlated with the total duration of physical exercises for most intensity categories. A similar correlation was established between pedagogical characteristics of the training process and the aldosterone to cortisol ratio. PMID:21834470

  6. [Physical-mechanical and functional characteristics of xenograft during various methods of stabilization and treatment].

    PubMed

    Kondratenko, Zh E; Kostava, V T; Bakuleva, N P; Tereshchenkova, I A; Antipas, D B

    1998-01-01

    The paper gives the results of experimental studies of the elastic-strength and functional characteristics of xenotissue samples (the pericardium of the calf, pig and Glisson's capsule) stabilized with glutaric aldehyde and polyepoxy compounds. The paper discusses various treatments of biological materials (including Glisson's capsule) anticalcified with additives (sodium dodecyl sulfate, complexes of copper and zinc) and shows that their use improves proteolytic and calcinotic resistance without deteriorating the mechanical parameters of xenotissues. Comparative analysis of the physical-mechanic and functional characteristics of xenotissues treated in different ways allows one to make anticalcifying treatment of biological tissues with copper and zinc complexes physical-mechanic and functional characteristics of xenotissues (Glisson's capsule) for clinical application. PMID:9791850

  7. The evaluation of a shuttle borne lidar experiment to measure the global distribution of aerosols and their effect on the atmospheric heat budget

    NASA Technical Reports Server (NTRS)

    Shipley, S. T.; Joseph, J. H.; Trauger, J. T.; Guetter, P. J.; Eloranta, E. W.; Lawler, J. E.; Wiscombe, W. J.; Odell, A. P.; Roesler, F. L.; Weinman, J. A.

    1975-01-01

    A shuttle-borne lidar system is described, which will provide basic data about aerosol distributions for developing climatological models. Topics discussed include: (1) present knowledge of the physical characteristics of desert aerosols and the absorption characteristics of atmospheric gas, (2) radiative heating computations, and (3) general circulation models. The characteristics of a shuttle-borne radar are presented along with some laboratory studies which identify schemes that permit the implementation of a high spectral resolution lidar system.

  8. The stratospheric sulfate aerosol layer - Processes, models, observations, and simulations

    NASA Technical Reports Server (NTRS)

    Whitten, R. C.; Toon, O. B.; Turco, R. P.

    1980-01-01

    After briefly reviewing the observational data on the stratospheric sulfate aerosol layer, the chemical and physical processes that are likely to fix the properties of the layer are discussed. We present appropriate continuity equations for aerosol particles, and show how to solve the equations on a digital computer. Simulations of the unperturbed aerosol layer by various published models are discussed and the sensitivity of layer characteristics to variations in several aerosol model parameters is studied. We discuss model applications to anthropogenic pollution problems and demonstrate that moderate levels of aerospace activity (supersonic transport and Space Shuttle operations) will probably have only a negligible effect on global climate. Finally, we evaluate the possible climatic effect of a ten-fold increase in the atmospheric abundance of carbonyl sulfide.

  9. Correlations between absorption Angström exponent (AAE) of wintertime ambient urban aerosol and its physical and chemical properties

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Filep, Á.; Pintér, M.; Török, Zs.; Bozóki, Z.; Szabó, G.

    2014-07-01

    Based on a two-week measurement campaign in an environment heavily polluted both by transit traffic and household heating in the inner city of Szeged (Hungary), correlations between the absorption Angström exponent (AAE) fitted to the optical absorption coefficients measured with a four wavelength (1064, 532, 355 and 266 nm) photoacoustic aerosol measuring system (4λ-PAS) and various aerosol parameters were identified. AAE was found to depend linearly on OCwb/EC and on NGM100/NGMD20, i.e. on the ratio of mass concentrations of elemental carbon (EC) to the fraction of organic carbon associated with wood burning (OCwb), and on the ratio of aerosol number concentrations in the 20 nm (NGMD20) to 100 nm (NGMD100) modes, with a regression coefficient of R = 0.95 and R = 0.86, respectively. In the daily fluctuation of AAE two minima were identified, which coincide with the morning and afternoon rush hours, during which NGMD20 exhibits maximum values. During the campaign the shape of the aerosol volume size distribution (dV/dlogD) was found to be largely invariant, supporting the assumption that the primary driver for the AAE variation was aerosol chemical composition rather than particle size. Furthermore, when wavelength segregated AAE values were calculated, AAE for the shorter wavelengths (AAE355-266) was also found to depend linearly on the above mentioned ratios with similar regression coefficients but with a much steeper correlation line, while the AAE for the longer wavelengths (AAE1064-532) exhibits only a considerably weaker correlation. These results prove the unique advantages of real time multi-wavelength photoacoustic measurement of optical absorption in case the wavelength range includes the ultra-violet too.

  10. Chemical and physical influences on aerosol activation in liquid clouds: a study based on observations from the Jungfraujoch, Switzerland

    SciTech Connect

    Hoyle, Christopher R.; Webster, Clare S.; Rieder, Harald E.; Nenes, Athanasios; Hammer, Emanuel; Herrmann, Erik; Gysel, Martin; Bukowiecki, Nicolas; Weingartner, Ernest; Steinbacher, Martin; Baltensperger, Urs

    2016-01-01

    A simple statistical model to predict the number of aerosols which activate to form cloud droplets in warm clouds has been established, based on regression analysis of data from four summertime Cloud and Aerosol Characterisation Experiments (CLACE) at the high-altitude site Jungfraujoch (JFJ). It is shown that 79 % of the observed variance in droplet numbers can be represented by a model accounting only for the number of potential cloud condensation nuclei (defined as number of particles larger than 80 nm in diameter), while the mean errors in the model representation may be reduced by the addition of further explanatory variables, such as the mixing ratios of O3, CO, and the height of the measurements above cloud base. The statistical model has a similar ability to represent the observed droplet numbers in each of the individual years, as well as for the two predominant local wind directions at the JFJ (northwest and southeast). Given the central European location of the JFJ, with air masses in summer being representative of the free troposphere with regular boundary layer in-mixing via convection, we expect that this statistical model is generally applicable to warm clouds under conditions where droplet formation is aerosol limited (i.e. at relatively high updraught velocities and/or relatively low aerosol number concentrations). A comparison between the statistical model and an established microphysical parametrization shows good agreement between the two and supports the conclusion that cloud droplet formation at the JFJ is predominantly controlled by the number concentration of aerosol particles.

  11. Chemical and physical influences on aerosol activation in liquid clouds: a study based on observations from the Jungfraujoch, Switzerland

    NASA Astrophysics Data System (ADS)

    Hoyle, Christopher R.; Webster, Clare S.; Rieder, Harald E.; Nenes, Athanasios; Hammer, Emanuel; Herrmann, Erik; Gysel, Martin; Bukowiecki, Nicolas; Weingartner, Ernest; Steinbacher, Martin; Baltensperger, Urs

    2016-03-01

    A simple statistical model to predict the number of aerosols which activate to form cloud droplets in warm clouds has been established, based on regression analysis of data from four summertime Cloud and Aerosol Characterisation Experiments (CLACE) at the high-altitude site Jungfraujoch (JFJ). It is shown that 79 % of the observed variance in droplet numbers can be represented by a model accounting only for the number of potential cloud condensation nuclei (defined as number of particles larger than 80 nm in diameter), while the mean errors in the model representation may be reduced by the addition of further explanatory variables, such as the mixing ratios of O3, CO, and the height of the measurements above cloud base. The statistical model has a similar ability to represent the observed droplet numbers in each of the individual years, as well as for the two predominant local wind directions at the JFJ (northwest and southeast). Given the central European location of the JFJ, with air masses in summer being representative of the free troposphere with regular boundary layer in-mixing via convection, we expect that this statistical model is generally applicable to warm clouds under conditions where droplet formation is aerosol limited (i.e. at relatively high updraught velocities and/or relatively low aerosol number concentrations). A comparison between the statistical model and an established microphysical parametrization shows good agreement between the two and supports the conclusion that cloud droplet formation at the JFJ is predominantly controlled by the number concentration of aerosol particles.

  12. Chemical and physical influences on aerosol activation in liquid clouds: a study based on observations from the Jungfraujoch, Switzerland

    DOE PAGESBeta

    Hoyle, Christopher R.; Webster, Clare S.; Rieder, Harald E.; Nenes, Athanasios; Hammer, Emanuel; Herrmann, Erik; Gysel, Martin; Bukowiecki, Nicolas; Weingartner, Ernest; Steinbacher, Martin; et al

    2016-03-29

    In this study, a simple statistical model to predict the number of aerosols which activate to form cloud droplets in warm clouds has been established, based on regression analysis of data from four summertime Cloud and Aerosol Characterisation Experiments (CLACE) at the high-altitude site Jungfraujoch (JFJ). It is shown that 79 % of the observed variance in droplet numbers can be represented by a model accounting only for the number of potential cloud condensation nuclei (defined as number of particles larger than 80 nm in diameter), while the mean errors in the model representation may be reduced by the additionmore » of further explanatory variables, such as the mixing ratios of O3, CO, and the height of the measurements above cloud base. The statistical model has a similar ability to represent the observed droplet numbers in each of the individual years, as well as for the two predominant local wind directions at the JFJ (northwest and southeast). Given the central European location of the JFJ, with air masses in summer being representative of the free troposphere with regular boundary layer in-mixing via convection, we expect that this statistical model is generally applicable to warm clouds under conditions where droplet formation is aerosol limited (i.e. at relatively high updraught velocities and/or relatively low aerosol number concentrations). Finally, a comparison between the statistical model and an established microphysical parametrization shows good agreement between the two and supports the conclusion that cloud droplet formation at the JFJ is predominantly controlled by the number concentration of aerosol particles.« less

  13. Aerosol Climate Interactions in Climate System Models

    NASA Astrophysics Data System (ADS)

    Kiehl, J. T.

    2002-12-01

    Aerosols are widely recognized as an important process in Earth's climate system. Observations over the past decade have improved our understanding of the physical and chemical properties of aerosols. Recently, field observations have highlighted the pervasiveness of absorbing aerosols in the atmosphere. These aerosols are of particular interest, since they alter the vertical distribution of shortwave radiative heating between the surface and atmosphere. Given this increased knowledge of aerosols from various field programs, interest is focusing on how to integrate this understanding into global climate models. These types of models provide the best tool available to comprehensively study the potential effects of aerosols on Earth's climate system. Results from climate system model simulations that include aerosol effects will be presented to illustrate key aerosol climate interactions. These simulations employ idealized and realistic distributions of absorbing aerosols. The idealized aerosol simulations provide insight into the role of aerosol shortwave absorption on the global hydrologic cycle. The realistic aerosol distributions provide insight into the local response of aerosol forcing in the Indian subcontinent region. Emphasis from these simulations will be on the hydrologic cycle, since water availability is of emerging global environmental concern. This presentation will also consider what more is needed to significantly improve our ability to model aerosol processes in climate system models. Uncertainty in aerosol climate interactions remains a major source of uncertainty in our ability to project future climate change. Focus will be on interactions between aerosols and various physical, chemical and biogeochemical aspects of the Earth system.

  14. Ship diesel emission aerosols: A comprehensive study on the chemical composition, the physical properties and the molecular biological and toxicological effects on human lung cells of aerosols from a ship diesel engine operated with heavy or light diesel fuel oil

    NASA Astrophysics Data System (ADS)

    Zimmermann, R.; Buters, J.; Öder, S.; Dietmar, G.; Kanashova, T.; Paur, H.; Dilger, M.; Mülhopt, S.; Harndorf, H.; Stengel, B.; Rabe, R.; Hirvonen, M.; Jokiniemi, J.; Hiller, K.; Sapcariu, S.; Berube, K.; Sippula, O.; Streibel, T.; Karg, E.; Schnelle-Kreis, J.; Lintelmann, J.; Sklorz, M.; Arteaga Salas, M.; Orasche, J.; Müller, L.; Reda, A.; Passig, J.; Radischat, C.; Gröger, T.; Weiss, C.

    2013-12-01

    The Virtual Helmholtz Institute-HICE (www.hice-vi.eu) addresses chemical & physical properties, transformation processes and health effects of anthropogenic combustion emissions. This is performed by thorough comprehensive chemical and physical characterization of combustion aerosols (including application of advantageous on-line methods) and studying of biological effects on human lung cell-cultures. A new ALI air-liquid-interface (ALI) exposition system and a mobile S2-biological laboratory were developed for the HICE-measurements. Human alveolar basal epithelial cells (A549 etc.) are ALI-exposed to fresh, diluted (1:40-1:100) combustion aerosols and subsequently were toxicologically and molecular-biologically characterized (e.g. proteomics). By using stable isotope labeling technologies (13C-Glucose/metabolomics; 2H-Lysine/SILAC-proteomics), high sensitivity and accuracy for detection of molecular-biological effects is achievable even at sub-toxic effect dose levels. Aerosols from wood combustion and ship diesel engine (heavy/light fuel oil) have been investigated. The effect of wood combustion and ship diesel PM e.g. on the protein expression of ALI-exposed A549 cells was compared. Filtered aerosol is used as gas-reference for the isotope labeling based method (SILAC). Therefore the effects of wood combustion- and shipping diesel-PM can be directly compared. Ship diesel aerosol causes a broader distribution in the observed fold changes (log2), i.e. more proteins are significantly up-/down-regulated in case of shipping diesel PM-exposure. This corresponds to a stronger biological reaction if compared to wood combustion-PM exposure. The chemical analysis results on wood combustion- and ship diesel-PM depict more polycyclic aromatic hydrocarbons (PAH)/oxidized-PAH but less of some transition metals (V, Fe) in the wood combustion case. Interestingly, alkylated PAH are considerably more abundant in shipping PM, suggesting that PAH/Oxy-PAH may be less relevant for

  15. Sources and characteristics of fine particles over the Yellow Sea and Bohai Sea using online single particle aerosol mass spectrometer.

    PubMed

    Fu, Huaiyu; Zheng, Mei; Yan, Caiqing; Li, Xiaoying; Gao, Huiwang; Yao, Xiaohong; Guo, Zhigang; Zhang, Yuanhang

    2015-03-01

    Marine aerosols over the East China Seas are heavily polluted by continental sources. During the Chinese Comprehensive Ocean Experiment in November 2012, size and mass spectra of individual atmospheric particles in the size range from 0.2 to 2.0 μm were measured on board by a single particle aerosol mass spectrometer (SPAMS). The average hourly particle number (PN) was around 4560±3240 in the South Yellow Sea (SYS), 2900±3970 in the North Yellow Sea (NYS), and 1700±2220 in the Bohai Sea (BS). PN in NYS and BS varied greatly over 3 orders of magnitude, while that in SYS varied slightly. The size distributions were fitted with two log-normal modes. Accumulation mode dominated in NYS and BS, especially during episodic periods. Coarse mode particles played an important role in SYS. Particles were classified using an adaptive resonance theory based neural network algorithm (ART-2a). Six particle types were identified with secondary-containing, aged sea-salt, soot-like, biomass burning, fresh sea-salt, and lead-containing particles accounting for 32%, 21%, 18%, 16%, 4%, and 3% of total PN, respectively. Aerosols in BS were relatively enriched in particles from anthropogenic sources compared to SYS, probably due to emissions from more developed upwind regions and indicating stronger influence of continental outflow on marine environment. Variation of source types depended mainly on origins of transported air masses. This study examined rapid changes in PN, size distribution and source types of fine particles in marine atmospheres. It also demonstrated the effectiveness of high-time-resolution source apportionment by ART-2a. PMID:25766014

  16. Fish assemblage relationships with physical characteristics and presence of dams in three eastern Iowa rivers

    USGS Publications Warehouse

    Pierce, Clay; Nicholas L. Ahrens; Anna K. Loan-Wilsey; Gregory A. Simmons; Gregory T. Gelwicks

    2013-01-01

    Fish assemblages in rivers of the Midwestern United States are an important component of the region's natural resources and biodiversity. We characterized the physical environment and presence of dams in a series of reaches in three eastern Iowa rivers tributary to the Mississippi River and related these characteristics to the fish assemblages present. Some physical characteristics were similar among the 12 study reaches, whereas others differed substantially. We found a total of 68 species across the 12 study reaches; 56 in the Turkey River, 51 in the Maquoketa River and 50 in the Wapsipinicon River. Seventeen species could be described as ‘downstream-distributed’; 15 being found only in the lowest reach of one or more rivers and the other two being found only in the lowest reaches or two or more contiguous reaches including the lowest reach. Two species could be described as ‘upstream-distributed’, being found only in an uppermost reach. Non-metric multidimensional scaling ordination illustrated similarities among reaches, and five physical variables were significantly correlated with assemblage similarities. Catchment area and number of dams between reaches and the Mississippi River were strongly correlated with assemblage similarities, but the directions of their effects were opposite. Catchment area and number of dams were confounded. The collective evidence to date suggests that the pervasiveness of dams on rivers significantly alters fish assemblages, making underlying patterns of species change and relationships with naturally varying and human-influenced physical characteristics along a river's course difficult to discern.

  17. Use of high-volume outdoor smog chamber photo-reactors for studying physical and chemical atmospheric aerosol formation and composition

    NASA Astrophysics Data System (ADS)

    Borrás, E.; Ródenas, M.; Vera, T.; Muñoz, A.

    2015-12-01

    The atmospheric particulate matter has a large impact on climate, biosphere behaviour and human health. Its study is complex because of large number of species are present at low concentrations and the continuous time evolution, being not easily separable from meteorology, and transport processes. Closed systems have been proposed by isolating specific reactions, pollutants or products and controlling the oxidizing environment. High volume simulation chambers, such as EUropean PHOtoREactor (EUPHORE), are an essential tool used to simulate atmospheric photochemical reactions. This communication describes the last results about the reactivity of prominent atmospheric pollutants and the subsequent particulate matter formation. Specific experiments focused on organic aerosols have been developed at the EUPHORE photo-reactor. The use of on-line instrumentation, supported by off-line techniques, has provided well-defined reaction profiles, physical properties, and up to 300 different species are determined in particulate matter. The application fields include the degradation of anthropogenic and biogenic pollutants, and pesticides under several atmospheric conditions, studying their contribution on the formation of secondary organic aerosols (SOA). The studies performed at the EUPHORE have improved the mechanistic studies of atmospheric degradation processes and the knowledge about the chemical and physical properties of atmospheric particulate matter formed during these processes.

  18. A technical feasibility study of dornase alfa delivery with eFlow® vibrating membrane nebulizers: aerosol characteristics and physicochemical stability.

    PubMed

    Scherer, Thomas; Geller, David E; Owyang, Laura; Tservistas, Marcus; Keller, Manfred; Boden, Norbert; Kesser, Kenneth C; Shire, Steven J

    2011-01-01

    Dornase alfa (Pulmozyme®) is an inhaled mucus-active drug that decreases viscoelasticity of sputum in vitro, improves lung function and reduces respiratory exacerbations in cystic fibrosis (CF) patients of 5 years age and older. The regulatory approval of dornase alfa 15 years ago stipulated that only certain jet nebulizer-compressor combinations should be used to deliver the drug. Since that time there have been significant advances in aerosol delivery technology, including development of electronic perforated vibrating membrane devices. Three independent laboratories studied aerosol characteristics, nebulization time, dose delivery, and stability of dornase alfa after nebulization to determine the feasibility of using perforated vibrating membrane devices to deliver the drug. These studies determined that the eFlow® vibrating membrane technology delivers dornase alfa more rapidly and efficiently than jet nebulizers, and does not affect the physicochemical properties of the drug. These in vitro results demonstrate only the technical feasibility of using vibrating membrane devices to deliver dornase alfa. Clinical studies will be required before any conclusions can be made regarding clinical safety and efficacy of these drug-device combinations for cystic fibrosis. PMID:20533437

  19. Investigating the frequency and interannual variability in global above-cloud aerosol characteristics with CALIOP and OMI

    NASA Astrophysics Data System (ADS)

    Alfaro-Contreras, R.; Zhang, J.; Campbell, J. R.; Reid, J. S.

    2016-01-01

    Seven and a half years (June 2006 to November 2013) of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aerosol and cloud layer products are compared with collocated Ozone Monitoring Instrument (OMI) aerosol index (AI) data and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) cloud products in order to investigate variability in estimates of biannual and monthly above-cloud aerosol (ACA) events globally. The active- (CALIOP) and passive-based (OMI-MODIS) techniques have their advantages and caveats for ACA detection, and thus both are used to derive a thorough and robust comparison of daytime cloudy-sky ACA distribution and climatology. For the first time, baseline above-cloud aerosol optical depth (ACAOD) and AI thresholds are derived and examined (AI = 1.0, ACAOD = 0.015) for each sensor. Both OMI-MODIS and CALIOP-based daytime spatial distributions of ACA events show similar patterns during both study periods (December-May) and (June-November). Divergence exists in some regions, however, such as Southeast Asia during June through November, where daytime cloudy-sky ACA frequencies of up to 10 % are found from CALIOP yet are non-existent from the OMI-based method. Conversely, annual cloudy-sky ACA frequencies of 20-30 % are reported over northern Africa from the OMI-based method yet are largely undetected by the CALIOP-based method. Using a collocated OMI-MODIS-CALIOP data set, our study suggests that the cloudy-sky ACA frequency differences between the OMI-MODIS- and CALIOP-based methods are mostly due to differences in cloud detection capability between MODIS and CALIOP as well as QA flags used. An increasing interannual variability of ˜ 0.3-0.4 % per year (since 2009) in global monthly cloudy-sky ACA daytime frequency of occurrence is found using the OMI-MODIS-based method. Yet, CALIOP-based global daytime ACA frequencies exhibit a near-zero interannual variability. Further analysis suggests that the OMI-derived interannual variability in

  20. Remote Marine Aerosol: A Characterization of Physical, Chemical and Optical Properties and their Relation to Radiative Transfer in the Troposphere

    NASA Technical Reports Server (NTRS)

    Clarke, Antony D.; Porter, John N.

    1997-01-01

    Our research effort is focused on improving our understanding of aerosol properties needed for optical models for remote marine regions. This includes in-situ and vertical column optical closure and involves a redundancy of approaches to measure and model optical properties that must be self consistent. The model is based upon measured in-situ aerosol properties and will be tested and constrained by the vertically measured spectral differential optical depth of the marine boundary layer, MBL. Both measured and modeled column optical properties for the boundary layer, when added to the free-troposphere and stratospheric optical depth, will be used to establish spectral optical depth over the entire atmospheric column for comparison to and validation of satellite derived radiances (AVHRR).

  1. Physical analysis of intravascular low-reation-lever laser irradiation therapy on improving the hemorheologic characteristics

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoran; Lu, Jian; Wang, Yawei; Ni, Xiaowu

    1999-09-01

    Many clinical results showed that intravascular low-reaction- lever laser irradiation therapy (ILLLI) could improve the hemorheologic characteristics. The red blood cell (RBC) aggregation index, the blood viscosity and the erythrocyte sedimentation rate (ESR) were reduced significantly by treatment with ILLLI. In this paper, a physical process is proposed that laser makes the H-bond parted, which would give rise to a decrease in the RBC aggregation index. According to the principle of hemorheologic characteristics, the blood viscosity and the ESR reduce with the decrease in the RBC aggregation index.

  2. Stratospheric Aerosol and Gas Experiment (SAGE) II and III Aerosol Extinction Measurements in the Arctic Middle and Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Treffeisen, R. E.; Thomason, L. W.; Strom, J.; Herber, A. B.; Burton, S. P.; Yamanouchi, T.

    2006-01-01

    In recent years, substantial effort has been expended toward understanding the impact of tropospheric aerosols on Arctic climate and chemistry. A significant part of this effort has been the collection and documentation of extensive aerosol physical and optical property data sets. However, the data sets present significant interpretive challenges because of the diverse nature of these measurements. Among the longest continuous records is that by the spaceborne Stratospheric Aerosol and Gas Experiment (SAGE) II. Although SAGE tropospheric measurements are restricted to the middle and upper troposphere, they may be able to provide significant insight into the nature and variability of tropospheric aerosol, particularly when combined with ground and airborne observations. This paper demonstrates the capacity of aerosol products from SAGE II and its follow-on experiment SAGE III to describe the temporal and vertical variations of Arctic aerosol characteristics. We find that the measurements from both instruments are consistent enough to be combined. Using this combined data set, we detect a clear annual cycle in the aerosol extinction for the middle and upper Arctic troposphere.

  3. Physical characteristics of stream subbasins in the Chippewa River basin, west-central Minnesota

    USGS Publications Warehouse

    Sanocki, C.A.; Krumrie, J.R.

    1994-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected points on streams in the Chippewa River Basin, located in west-central Minnesota, are presented in this report The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slope. The points on the stream include outlets of subbasins of at least 5 square miles, outlets of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  4. Physical characteristics of a new synthetic fiber mattress in relation to pressure sores.

    PubMed

    Mita, K; Akataki, K; Itoh, K; Yoshida, M; Shinoda, T; Ishida, Y

    1997-01-01

    The purpose of the present investigation was to develop a mattress which was made of the new synthetic fibers called 'Shin-Gosen', and to determine its physical characteristics associated with pressure sores such as pressure distribution, temperature and humidity. The Shin-Gosen mattress consisted of three layers of elastic fibers made of polyester multifilaments, which were mediated by four layers of wave-like fabrics made of nylon monofilaments. The physical characteristics of the mattress were compared with (a) the conventional cotton hospital mattress and (b) the SORELESS MAT made of vacuole gel which effectively eliminated compression forces. The Shin-Gosen mattress was found to provide pressure relief effects similar to that of the SORELESS MAT the desired thermal insulation as well as that of the cotton mattress and a higher level of moisture vapor permeability. These excellent features will not only contribute to preventing pressure sores, but will also enable comfortable resting and sleeping. PMID:9444514

  5. Carbonaceous aerosols of aviation and shipping emissions

    NASA Astrophysics Data System (ADS)

    Popovicheva, O. B.; Kireeva, E. D.; Timofeev, M. A.; Shonija, N. K.; Mogil'Nikov, V. P.

    2010-06-01

    This is a study of the physical and chemical properties of carbonaceous aerosols emitted by transport systems (namely, by aircraft gas turbine engines and large ship diesel engines) into the atmosphere. A comparative analysis of the morphology, size, elemental composition, and surface chemistry between aviation and diesel soot particles reveals the general and characteristic features of emissions from each source. The high pollution rate of diesel soot particles, considerable fraction of metal admixtures, and availability of char particles characterize the specific features of the formation of particles of this type. The main characteristics characterizing the interaction between aviation and shipping emission aerosols in the moist atmosphere (the composition of organic and water-soluble fractions at the surface) have been obtained. Due to high hygroscopicity, the microparticles can generate cloud condensation nuclei and initiate contrails and additional tropospheric cloudiness.

  6. Interpretation of Aerosol Optical and Morphological Properties during the Carbonaceous Aerosols and Radiative Effects Study in Sacramento, June 2010

    NASA Astrophysics Data System (ADS)

    Gorkowski, K.; Mazzoleni, C.; China, S.; Sharma, N.; Flowers, B. A.; Dubey, M. K.; Gyawali, M. S.; Arnott, W. P.; Zaveri, R. A.

    2010-12-01

    The Sacramento Carbonaceous Aerosols and Radiative Effects Study (CARES) utilized two ground sites T0 and T1 along with an aircraft platform to characterize carbonaceous aerosol chemical and physical properties and their evolution. The T0 site was chosen within the Sacramento metropolitan area for measuring primary and secondary aerosols generated in the city. The T1 site was chosen East of Sacramento on the Sierra foothill to study the evolution and processing of the Sacramento aerosol plume and to assess the characteristics of the background air. To reach T1, the Sacramento aerosols traveled often over the Blodgett Forest resulting in significant aging due coagulation, condensation, and photochemical processes. The ground sites were chosen for this unique and reoccurring transport pattern of the aerosols. The campaign took place in June 2010. Six Integrated Photoacoustic/Nephelometer Spectrometers (IPNSs) were installed at the sites to simultaneously record aerosol light scattering and absorption data. The optical properties of the aerosols were measured at 355nm (ultraviolet), 375nm (ultraviolet), 405nm (blue), 532nm (green), and 781nm (red). In conjugation with the IPNSs, aerosol filters for electron microscopy analysis were collected at each site; these were examined using a field emission scanning electron microscope to study the aerosol morphology. The origins of the air masses did vary daily, but a few general trends emerged. The processing of the IPNS data with a wavelet denoising technique greatly enhanced the signal to noise ratio of the measurements enabling a better understanding of the aerosol optical properties for various airmasses with different characteristics. Typically signals at both sites were lower than expected, however the processed signals from T0 clearly showed a daily rise and dilution of the Sacramento plume. Using the processed signals from both sites the transportation of the Sacramento plume was detectable. The IPNS data were

  7. The characteristics and origins of carbonaceous aerosol at a rural site of PRD in summer of 2006

    NASA Astrophysics Data System (ADS)

    Hu, W. W.; Hu, M.; Deng, Z. Q.; Xiao, R.; Kondo, Y.; Takegawa, N.; Zhao, Y. J.; Guo, S.; Zhang, Y. H.

    2012-02-01

    Both organic carbon (OC) and elemental carbon (EC) were measured during PRIDE-PRD 2006 summer campaign by using a semi-continuous thermal-optical carbon analyzer at a rural site, Back Garden (BG), which is located 50 km to the northwest of Guangzhou City. Together with the online EC/OC analyzer, various kinds of instruments related to aerosol chemical properties were employed here, which provided a good opportunity to check data quality. The concentrations of OC correlated well with the mass of organic matter (OM) and water soluble organic carbon (WSOC), implying the reliability of the data measured in this campaign. The average OC concentrations in fine particle for three typical periods during the campaign (local emission influence, typhoon and precipitation and normal days) were 28.1 μgC m-3, 4.0 μgC m-3 and 5.7 μgC m-3, respectively; and EC were 11.6 μgC m-3, 1.8 μgC m-3, and 3.3 μgC m-3, respectively. The diurnal patterns of EC and OC during the campaign were higher at night and in early morning than daytime, which was probably caused by the primary emission and accumulation in the occurrence of low boundary layer. Compared with the constant diurnal enhancement ratios of EC, the enhancement ratio of OC (OC versus (CO-CObackground)) kept in a relative high level in the afternoon, with a similar diurnal profile to oxygenated organic aerosol (OOA), due to the strong photochemical formation of OC. Here, a modified EC tracer method was used to estimate the formation of secondary organic carbon (SOC). These results showed that the average SOC concentration (normal days) at BG site was about 2.0 ± 2.3 μgC m-3, and the SOC fraction in OC could reach up to 80% with the average of 47%. The modified approach in this study proved to be effective and reliable for SOC estimation based on good correlations between estimated SOC versus OOA or WSOC, and estimated POC versus hydrocarbon-like organic aerosol (HOA).

  8. Characteristics and the origins of the carbonaceous aerosol at a rural site of PRD in summer 2006

    NASA Astrophysics Data System (ADS)

    Hu, W. W.; Hu, M.; Deng, Z. Q.; Xiao, R.; Kondo, Y.; Takegawa, N.; Zhao, Y. J.; Guo, S.; Zhang, Y. H.

    2011-07-01

    Both organic carbon (OC) and elemental carbon (EC) were measured at a rural site, Back Garden (BG), 50km northwest of the Guangzhou City, by using a semi-continuous thermal-optical analyzer during PRIDE-PRD 2006 summer intensive campaign. Together with the online EC/OC instrument, multiple instruments were also employed here which provided a good opportunity to check data quality. The regressions between the mass of organic aerosol (OM) and OC, as well as OC and water soluble organic carbon (WSOC) imply reliability of the data measured in this campaign. The average OC concentrations in fine particle for three typical periods during the campaign (local emission influence, typhoon and participation, normal days) were 28.1 μg C m-3, 4.0 μg C m-3 and 5.7 μg C m-3, respectively, and EC were 11.6 μg C m-3, 1.8 μg C m-3, and 3.3 μg C m-3 orderly. Diurnal variations of EC and OC showed that there were two peaks for EC and OC concentrations, i.e. at night and early morning, which were probably caused by the primary emission accumulation when the boundary layer was shallow. Compare to the constant diurnal enhancement ratios of primary EC, the enhancement ratio of OC (OC versus (CO-CObackground)) remained in a relative high level in the afternoon with a similar diurnal variation to oxygenated organic aerosol (OOA), indicating the strong photochemical formation of OC. The traditional EC tracer method was modified to estimate the secondary organic carbon (SOC) formation, which shows that the average SOC concentration in BG site was about 2.0 ± 2.3 μg C m-3.The SOC fraction in OC reached up to 80 % with the average of 47 %. Good correlations between estimated SOC versus measured OOA or WSOC, and estimated POC versus measured hydrocarbon-like organic aerosol (HOA) also proved the reliable results by the modified EC tracer method in this paper.

  9. Biological aerosol background characterization

    NASA Astrophysics Data System (ADS)

    Blatny, Janet; Fountain, Augustus W., III

    2011-05-01

    To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge