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Sample records for aerosol characterization experiments

  1. Source term experiments project (STEP): aerosol characterization system

    SciTech Connect

    Schlenger, B.J.; Dunn, P.F.

    1985-01-01

    A series of four experiments is being conducted at Argonne National Laboratory's TREAT Reactor. They have been designed to provide some of the necessary data regarding magnitude and release rates of fission products from degraded fuel pins, physical and chemical characteristics of released fission products, and aerosol formation and transport phenomena. These are in-pile experiments, whereby the test fuel is heated by neutron induced fission and subsequent clad oxidation in steam environments that simulate as closely as practical predicted reactor accident conditions. The test sequences cover a range of pressure and fuel heatup rate, and include the effect of Ag/In/Cd control rod material.

  2. The Hohenpeissenberg aerosol characterization experiment (HAZE2002): Aerosol composition derived from mass spectrometry

    NASA Astrophysics Data System (ADS)

    Hock, N.; Berresheim, H.; Borrmann, S.; Poeschl, U.; Roempp, A.; Schneider, J.

    2003-04-01

    The HAZE Experiment was conducted between 17.05.2002 and 31.05.2002, at the meteorological observatory of the Deutsche Wetterdienst (DWD) at Hohenpeissenberg (47^o48'N,11^o02'E, 985m). The objective was to make essential progress in understanding of the physical and chemical properties of the atmospheric aerosol, in particular relating to the Gas-To-Particle-Conversion and the interaction with meteorological processes. The measurements included online mass spectrometric analysis using the Aerosol Mass Spectrometer (AMS), filter samples with GC analyses of organic compounds, particle size distribution (Electrical Low Pressure Impactor (ELPI), SMPS, OPC), as well as the total particle concentration (CPC). Additionally, several gas-phase substances were measured (e.g. Benzene, Acetone). The measurements obtained with the AMS show a strong variability of the aerosol composition. The non-refractory aerosol composition was dominated by nitrate, sulphate, and organics, whereas ammonium was surprisingly low. High number concentration of up to 14000 particles/cm^3 were observed. These particles mostly had diameters between 200 nm and 400 nm and were mainly composed of ammonium sulphate and ammonium nitrate. Various meteorological conditions allowed to study their influence on the aerosol. For example, on rainy days the concentrations of ammonium sulphate particles decreased, whereas the concentrations of ammonium nitrate particles increased.

  3. Generation and characterization of aerosols and vapors for inhalation experiments.

    PubMed Central

    Tillery, M I; Wood, G O; Ettinger, H J

    1976-01-01

    Control of aerosol and vapor characteristics that affect the toxicity of inhaled contaminants often determines the methods of generating exposure atmospheres. Generation methods for aerosols and vapors are presented. The characteristics of the resulting exposure atmosphere and the limitations of the various generation methods are discussed. Methods and instruments for measuring the airborne contaminant with respect to various charcteristics are also described. PMID:797565

  4. Rural continental aerosol properties and processes observed during the Hohenpeissenberg Aerosol Characterization Experiment (HAZE2002)

    NASA Astrophysics Data System (ADS)

    Hock, N.; Schneider, J.; Borrmann, S.; Römpp, A.; Moortgat, G.; Franze, T.; Schauer, C.; Pöschl, U.; Plass-Dülmer, C.; Berresheim, H.

    2007-06-01

    Detailed investigations of the chemical and microphysical properties of rural continental aerosols were performed during the HAZE2002 experiment, which was conducted in May 2002 at the Meteorological Observatory Hohenpeissenberg (DWD) in Southern Germany. The online measurement data and techniques included: size-resolved chemical composition of submicron particles by aerosol mass spectrometry (AMS); total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm (CPC, SMPS, OPC); monoterpenes determined by gas chromatography- ion trap mass spectrometry; OH and H2SO4 determined by atmospheric pressure chemical ionization mass spectrometry (CIMS). Filter sampling and offline analytical techniques were used to determine: fine particle mass (PM2.5), organic, elemental and total carbon in PM2.5 (OC2.5, EC2.5, TC2.5), and selected organic compounds (dicarboxylic acids, polycyclic aromatic hydrocarbons, proteins). Overall, the non-refractory components of submicron particles detected by aerosol mass spectrometry (PM1, 6.6±5.4 μg m-3, arithmetic mean and standard deviation) accounted for ~62% of PM2.5 determined by filter gravimetry (10.6±4.7 μg m-3). The relative proportions of non-refractory submicron particle components were: 11% ammonium, 19% nitrate, 20% sulfate, and 50% organics (OM1). In spite of strongly changing meteorological conditions and absolute concentration levels of particulate matter (3-13 μg m-3 PM1), OM1 was closely correlated with PM1 (r2=0.9) indicating a near-constant ratio of non-refractory organics and inorganics. In contrast, the ratio of nitrate to sulfate was highly dependent on temperature (14-32°C) and relative humidity (20-100%), which could be explained by thermodynamic model calculations of NH3/HNO3/NH4NO3 gas-particle partitioning. From the combination of optical and other sizing techniques (OPC, AMS, SMPS), an average refractive index of 1.40-1.45 was inferred for the measured rural aerosol

  5. Rural continental aerosol properties and processes observed during the Hohenpeissenberg Aerosol Characterization Experiment (HAZE2002)

    NASA Astrophysics Data System (ADS)

    Hock, N.; Schneider, J.; Borrmann, S.; Römpp, A.; Moortgat, G.; Franze, T.; Schauer, C.; Pöschl, U.; Plass-Dülmer, C.; Berresheim, H.

    2008-02-01

    Detailed investigations of the chemical and microphysical properties of rural continental aerosols were performed during the HAZE2002 experiment, which was conducted in May 2002 at the Meteorological Observatory Hohenpeissenberg (DWD) in Southern Germany. Online measurements included: Size-resolved chemical composition of submicron particles; total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm; gas-phase concentration of monoterpenes, CO, O3, OH, and H2SO4. Filter sampling and offline analytical techniques were used to determine: Fine particle mass (PM2.5), organic, elemental and total carbon in PM2.5 (OC2.5, EC2.5, TC2.5), and selected organic compounds (dicarboxylic acids, polycyclic aromatic hydrocarbons, proteins). Overall, the non-refractory components of submicron particles detected by aerosol mass spectrometry (PM1, 6.6±5.4 μg m-3, arithmetic mean and standard deviation) accounted for ~62% of PM2.5 determined by filter gravimetry (10.6±4.7 μg m-3). The relative proportions of non-refractory submicron particle components were: (23±39)% ammonium nitrate, (27±23)% ammonium sulfate, and (50±40)% organics (OM1). OM1 was closely correlated with PM1 (r2=0.9) indicating a near-constant ratio of non-refractory organics and inorganics. The average ratio of OM1 to OC2.5 was 2.1±1.4, indicating a high proportion of heteroelements in the organic fraction of the sampled rural aerosol. This is consistent with the high ratio of oxygenated organic aerosol (OOA) over hydrocarbon-like organic aerosol (HOA) inferred from the AMS results (4:1), and also with the high abundance of proteins (~3%) indicating a high proportion of primary biological material (~30%) in PM2.5. This finding was confirmed by low abundance of PAHs (<1 ng m-3) and EC (<1 μg m-3) in PM2.5 and detection of several secondary organic aerosol compounds (dicarboxylic acids) and their precursors (monoterpenes). New particle formation was observed almost

  6. Chemical Characterization of the Aerosol During the CLAMS Experiment Using Aircraft and Ground Stations

    NASA Astrophysics Data System (ADS)

    Castanho, A. D.; Martins, J.; Artaxo, P.; Hobbs, P. V.; Remer, L.; Yamasoe, M.; Fattori, A.

    2002-05-01

    During the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment Nuclepore filters were collected in two ground stations and aboard the University of Wasghington's Convair 580 Reserarch Aircraft. The two ground stations were chosen in strategic positions to characterize the chemical composition, the mass concentration, black carbon (BC) content, and the absorption properties of the aerosol particles at the surface level. One of the stations was located at the Cheasapeake lighthouse (25 km from the coast) and the other one was located at the Wallops Island. Aerosol particles where collected in two stages, fine (d<2.5um) and coarse mode (2.5experiment. Airborne samples were also collected on the UW Convair 580 Aircraft. The aircraft samples where used to characterize the elemental composition, mass concentration, BC content, and absorption properties of the aerosol in the atmospheric column in the CLAMS Experiment area. Some of the filters were also submitted to Scanning Electron Microscopy analysis. The particulate matter mass for all the samples were obtained gravimetrically. The concentration of black carbon in the fine filters was optically determined by a broadband reflectance technique. The spectral (from UV to near IR) reflectance in the fine and coarse mode filter were also obtained with a FieldSpec ASD spectrometer. Aerosol elemental characterization (Na through Pb) was obtained by the PIXE (Particle induced X ray emission) analyses of the nuclepore filters. The sources of the aerosol measured at the ground stations were estimated by principal component analyses mainly in the Wallops Island, where a longer time series was collected. One of the main urban components identified in the aerosol during the experiment was sulfate. Black carbon

  7. Experiment to Characterize Aircraft Volatile Aerosol and Trace-Species Emissions (EXCAVATE)

    NASA Technical Reports Server (NTRS)

    Anderson, B. E.; Branham, H.-S.; Hudgins, C. H.; Plant, J. V.; Ballenthin, J. O.; Miller, T. M.; Viggiano, A. A.; Blake, D. R.; Boudries, H.; Canagaratna, M.

    2005-01-01

    The Experiment to Characterize Aircraft Volatile and Trace Species Emissions (EXCAVATE) was conducted at Langley Research Center (LaRC) in January 2002 and focused upon assaying the production of aerosols and aerosol precursors by a modern commercial aircraft, the Langley B757, during ground-based operation. Remaining uncertainty in the postcombustion fate of jet fuel sulfur contaminants, the need for data to test new theories of particle formation and growth within engine exhaust plumes, and the need for observations to develop air quality models for predicting pollution levels in airport terminal areas were the primary factors motivating the experiment. NASA's Atmospheric Effects of Aviation Project (AEAP) and the Ultra Effect Engine Technology (UEET) Program sponsored the experiment which had the specific objectives of determining ion densities; the fraction of fuel S converted from S(IV) to S(VI); the concentration and speciation of volatile aerosols and black carbon; and gas-phase concentrations of long-chain hydrocarbon and PAH species, all as functions of engine power, fuel composition, and plume age.

  8. Ganges valley aerosol experiment.

    SciTech Connect

    Kotamarthi, V.R.; Satheesh, S.K.

    2011-08-01

    In June 2011, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective of this field campaign is to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region.

  9. Characterizing the impact of urban emissions on regional aerosol particles; airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouch, N.; Pichon, J.-M.; Prévôt, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2013-09-01

    The MEGAPOLI experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS) giving detailed information of the non-refractory submicron aerosol species. The mass concentration of BC, measured by a particle absorption soot photometer (PSAP), was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA), black carbon and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (-log(NOx / NOy). Plotting the equivalent ratios for the Positive Matrix Factorization (PMF) resolved species (LV-OOA, SV-OOA, and HOA) illustrate that the increase in OA is a result of secondary organic aerosol (SOA). Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in Mexico city, Mexico and in New England, USA. Using the measured VOCs species together with recent organic aerosol formation yields we predicted ~ 50% of the measured organics. These airborne measurements during the MEGAPOLI experiment show that urban emissions contribute to the formation of OA

  10. Characterizing the impact of urban emissions on regional aerosol particles: airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouche, N.; Pichon, J.-M.; Bourianne, T.; Gomes, L.; Prevot, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2014-02-01

    The MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris, using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS), giving detailed information on the non-refractory submicron aerosol species. The mass concentration of black carbon (BC), measured by a particle absorption soot photometer (PSAP), was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA), BC, and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (-log(NOx / NOy)). Plotting the equivalent ratios of different organic aerosol species (LV-OOA, SV-OOA, and HOA) illustrate that the increase in OA is a result of secondary organic aerosol (SOA) formation. Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in London, Mexico City, and in New England, USA. Using the measured SOA volatile organic compounds (VOCs) species together with organic aerosol formation

  11. A study on characterization of stratospheric aerosol and gas parameters with the spacecraft solar occultation experiment

    NASA Technical Reports Server (NTRS)

    Chu, W. P.

    1977-01-01

    Spacecraft remote sensing of stratospheric aerosol and ozone vertical profiles using the solar occultation experiment has been analyzed. A computer algorithm has been developed in which a two step inversion of the simulated data can be performed. The radiometric data are first inverted into a vertical extinction profile using a linear inversion algorithm. Then the multiwavelength extinction profiles are solved with a nonlinear least square algorithm to produce aerosol and ozone vertical profiles. Examples of inversion results are shown illustrating the resolution and noise sensitivity of the inversion algorithms.

  12. Ground-based aerosol characterization during the South American Biomass Burning Analysis (SAMBBA) field experiment

    NASA Astrophysics Data System (ADS)

    Brito, J.; Rizzo, L. V.; Morgan, W. T.; Coe, H.; Johnson, B.; Haywood, J.; Longo, K.; Freitas, S.; Andreae, M. O.; Artaxo, P.

    2014-11-01

    This paper investigates the physical and chemical characteristics of aerosols at ground level at a site heavily impacted by biomass burning. The site is located near Porto Velho, Rondônia, in the southwestern part of the Brazilian Amazon rainforest, and was selected for the deployment of a large suite of instruments, among them an Aerosol Chemical Speciation Monitor. Our measurements were made during the South American Biomass Burning Analysis (SAMBBA) field experiment, which consisted of a combination of aircraft and ground-based measurements over Brazil, aimed to investigate the impacts of biomass burning emissions on climate, air quality, and numerical weather prediction over South America. The campaign took place during the dry season and the transition to the wet season in September/October 2012. During most of the campaign, the site was impacted by regional biomass burning pollution (average CO mixing ratio of 0.6 ppm), occasionally superimposed by intense (up to 2 ppm of CO), freshly emitted biomass burning plumes. Aerosol number concentrations ranged from ~1000 cm-3 to peaks of up to 35 000 cm-3 (during biomass burning (BB) events, corresponding to an average submicron mass mean concentrations of 13.7 μg m-3 and peak concentrations close to 100 μg m-3. Organic aerosol strongly dominated the submicron non-refractory composition, with an average concentration of 11.4 μg m-3. The inorganic species, NH4, SO4, NO3, and Cl, were observed, on average, at concentrations of 0.44, 0.34, 0.19, and 0.01 μg m-3, respectively. Equivalent black carbon (BCe) ranged from 0.2 to 5.5 μg m-3, with an average concentration of 1.3 μg m-3. During BB peaks, organics accounted for over 90% of total mass (submicron non-refractory plus BCe), among the highest values described in the literature. We examined the ageing of biomass burning organic aerosol (BBOA) using the changes in the H : C and O : C ratios, and found that throughout most of the aerosol processing (O : C &cong

  13. Analysis of shipboard aerosol optical thickness measurements from multiple sunphotometers aboard the R/V Ronald H. Brown during the Aerosol Characterization Experiment - Asia

    NASA Astrophysics Data System (ADS)

    Miller, Mark A.; Knobelspiesse, Kirk; Frouin, Robert; Bartholomew, Mary Jane; Reynolds, R. Michael; Pietras, Christophe; Fargion, Giulietta; Quinn, Patricia; Thieuleux, François

    2005-06-01

    Marine sunphotometer measurements collected aboard the R/V Ronald H. Brown during the Aerosol Characterization Experiment - Asia (ACE-Asia) are used to evaluate the ability of complementary instrumentation to obtain the best possible estimates of aerosol optical thickness and Ångstrom exponent from ships at sea. A wide range of aerosol conditions, including clean maritime conditions and highly polluted coastal environments, were encountered during the ACE-Asia cruise. The results of this study suggest that shipboard hand-held sunphotometers and fast-rotating shadow-band radiometers (FRSRs) yield similar measurements and uncertainties if proper measurement protocols are used and if the instruments are properly calibrated. The automated FRSR has significantly better temporal resolution (2 min) than the hand-held sunphotometers when standard measurement protocols are used, so it more faithfully represents the variability of the local aerosol structure in polluted regions. Conversely, results suggest that the hand-held sunphotometers may perform better in clean, maritime air masses for unknown reasons. Results also show that the statistical distribution of the Ångstrom exponent measurements is different when the distributions from hand-held sunphotometers are compared with those from the FRSR and that the differences may arise from a combination of factors.

  14. Characterization of mineral dust aerosols during the Saharan Dust Experiment (SHADE)

    NASA Astrophysics Data System (ADS)

    Léon, J.-F.; Tanré, D.; Haywood, J.; Pelon, J.; Kaufman, Y. J.

    2003-04-01

    Aerosols are known to be important in determining the Earth’s radiative balance. Dust aerosols are particularly interesting since, in addition to their scattering and absorbing properties that affect the solar radiation, they also perturb the terrestrial radiation. In addition, recent studies have shown that a significant proportion of mineral dust in the atmosphere may be of anthropogenic origin and therefore they may have an important role in climate change by exerting a significant radiative forcing. The Saharan Dust Experiment was designed to better determine the parameters that are relevant for computing the direct radiative effect of mineral dust. Two aircraft combining in situ measurements and remote sensing instruments were coordinated with satellite overpasses during the experiment which was based in Cape Verde during the period September 20-28, 2000. These in-situ and remotely sensed data provide valuable information on the microphysical, optical properties and radiative effects of a very large mineral dust outbreak with aerosol optical thickness up to 1.5. A new approach based on a synergy between active (lidar) and passive (spaceborne radiometer) remote sensing has been used to investigate the vertical structure of the dust plume. The retrieved profiles of extinction compare well with in situ aircraft measurements. Profiles derived from lidar measurements on September 25 highlight the presence of the so-called Saharan Air Layer, located between 2.2 and 4.5 km. Another dust layer within the sub-Saharan transition layer over the marine boundary layer is also observed. In this second layer, the effective radius of particles is significantly smaller than in the aloft layer. The trajectory analyses and the Total Mapping Ozone Spectrometer Aerosol Index suggest that the aerosols present at 1500m originates from West Mauritania. The higher aerosol layer originates from southern Algeria which confirms the difference of altitude of the dust transport

  15. Morphological characterization of soot aerosol particles during LACIS Experiment in November (LExNo)

    NASA Astrophysics Data System (ADS)

    Kiselev, A.; Wennrich, C.; Stratmann, F.; Wex, H.; Henning, S.; Mentel, T. F.; Kiendler-Scharr, A.; Schneider, J.; Walter, S.; Lieberwirth, I.

    2010-06-01

    Combined mobility and aerodynamic measurements were used to characterize the morphology of soot particles in an experimental campaign on the hygroscopic growth and activation of an artificial biomass burning aerosol. A custom-made, single-stage low-pressure impactor and two aerosol mass spectrometers (AMS) operating in the free molecular regime were used to measure the vacuum aerodynamic diameter of mobility-selected artificial soot particles that were produced in a spark discharge generator and then modified by condensation of ammonium hydrogen sulfate or levoglucosan as a coating to change their hydroscopic activity. Transmission electron microscope images revealed a relationship between the electrical mobility diameter and the diameter of the enveloping sphere, thus enabling evaluation of the effective density of soot agglomerates. A fractal description of the morphology of the soot aggregates allowed for evaluation of the average mass of the hygroscopic material per particle. The average mass of the hygroscopic material per particle was also measured directly with the two AMS instruments, and the agreement between the two methods was found satisfactory. This tandem approach allows detection of small changes in the particle effective density and morphology caused by condensation of organic material.

  16. Aerosol characterization with lidar methods

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Nishizawa, Tomoaki; Shimizu, Atsushi; Matsui, Ichiro

    2014-08-01

    Aerosol component analysis methods for characterizing aerosols were developed for various types of lidars including polarization-sensitive Mie scattering lidars, multi-wavelength Raman scattering lidars, and multi-wavelength highspectral- resolution lidars. From the multi-parameter lidar data, the extinction coefficients for four aerosol components can be derived. The microphysical parameters such as single scattering albedo and effective radius can be also estimated from the derived aerosol component distributions.

  17. Aerosol composition, chemistry, and source characterization during the 2008 VOCALS Experiment

    SciTech Connect

    Lee, Y.; Springston, S.; Jayne, J.; Wang, J.; Senum, G.; Hubbe, J.; Alexander, L.; Brioude, J.; Spak, S.; Mena-Carrasco, M.; Kleinman, L.; Daum, P.

    2010-03-15

    Chemical composition of fine aerosol particles over the northern Chilean coastal waters was determined onboard the U.S. DOE G-1 aircraft during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) field campaign between October 16 and November 15, 2008. SO42-, NO3-, NH4+, and total organics (Org) were determined using an Aerodyne Aerosol Mass Spectrometer, and SO42-, NO3-, NH4+, Na+, Cl-, CH3SO3-, Mg2+, Ca2+, and K+ were determined using a particle-into-liquid sampler-ion chromatography technique. The results show the marine boundary layer (MBL) aerosol mass was dominated by non- sea-salt SO42- followed by Na+, Cl-, Org, NO3-, and NH4+, in decreasing importance; CH3SO3-, Ca2+, and K+ rarely exceeded their respective limits of detection. The SO42- aerosols were strongly acidic as the equivalent NH4+ to SO42- ratio was only {approx}0.25 on average. NaCl particles, presumably of sea-salt origin, showed chloride deficits but retained Cl- typically more than half the equivalency of Na+, and are externally mixed with the acidic sulfate aerosols. Nitrate was observed only on sea-salt particles, consistent with adsorption of HNO3 on sea-salt aerosols, responsible for the Cl- deficit. Dust particles appeared to play a minor role, judging from the small volume differences between that derived from the observed mass concentrations and that calculated based on particle size distributions. Because SO42- concentrations were substantial ({approx}0.5 - {approx}3 {micro}g/m3) with a strong gradient (highest near the shore), and the ocean-emitted dimethylsulfide and its unique oxidation product, CH3SO3-, were very low (i.e., {le} 40 parts per trillion and <0.05 {micro}g/m3, respectively), the observed SO42- aerosols are believed to be primarily of terrestrial origin. Back trajectory calculations indicate sulfur emissions from smelters and power plants along coastal regions of Peru and Chile are the main sources of these SO4- aerosols. However, compared to observations, model

  18. 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 of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

  19. Introduction and Overview of the AMazonian Aerosol characteriZation Experiment (AMAZE-08)

    NASA Astrophysics Data System (ADS)

    Martin, S. T.; Artaxo, P.; Team, A.

    2008-12-01

    The main objectives of AMAZE-08 were to understand the sources and regulators of organic particle mass in a pristine continental environment and the connections between particle chemistry and particle optical and hygroscopic properties. The AMAZE-08 tower measurements were conducted between February 7 and March 14, 2008 during the wet reason. The site was 60 km NNW of Manaus and located within a mostly pristine rainforest. The winds were predominantly from the ENE across 1600 km of mostly undeveloped forest. The site was mostly free of anthropogenic influences and allowed the study of pristine biological aerosol particles, although there were several episodes of long-range transport from Europe and Africa and more infrequent regional transport from Manaus and northerly biomass burning. Particle instrumentation included two high-resolution aerosol mass spectrometers (HR-ToF-AMS) with thermodenuder, two cloud condensation nuclei counters (CCNC), a continuous flow diffusion chamber (CFDC) for ice nuclei measurements, three optical particle counters (OPC), an ultraviolet aerodynamic particle sizer (UV-APS) for measurement of biologically active particles, two tapered element oscillating microbalances (TEOM), two scanning mobility particle sizers (SMPS), two multiwavelength nephelometers, three condensation particle counters (CPC), a multi-angle absorption photometer (MAAP), an athelometer, coarse- and fine-mode filters for elemental and ion analysis as well as particle imaging, an AERONET sun photometer including photosynthetically active radiation (PAR), and LIDAR system. Gas instrumentation included a proton-transfer mass spectrometer (PTR-MS), gas adsorption cartridge for off-line chromatographic analysis, and measurement of O3, CO, CO2, NO, and NOx. This talk will present an overview of AMAZE-08 and will highlight selected results.

  20. Aerosol retrieval experiments in the ESA Aerosol_cci project

    NASA Astrophysics Data System (ADS)

    Holzer-Popp, T.; de Leeuw, G.; Martynenko, D.; Klüser, L.; Bevan, S.; Davies, W.; Ducos, F.; Deuzé, J. L.; Graigner, R. G.; Heckel, A.; von Hoyningen-Hüne, W.; Kolmonen, P.; Litvinov, P.; North, P.; Poulsen, C. A.; Ramon, D.; Siddans, R.; Sogacheva, L.; Tanre, D.; Thomas, G. E.; Vountas, M.; Descloitres, J.; Griesfeller, J.; Kinne, S.; Schulz, M.; Pinnock, S.

    2013-03-01

    Within the ESA Climate Change Initiative (CCI) project Aerosol_cci (2010-2013) algorithms for the production of long-term total column aerosol optical depth (AOD) datasets from European Earth Observation sensors are developed. Starting with eight existing pre-cursor algorithms three analysis steps are conducted to improve and qualify the algorithms: (1) a series of experiments applied to one month of global data to understand several major sensitivities to assumptions needed due to the ill-posed nature of the underlying inversion problem, (2) a round robin exercise of "best" versions of each of these algorithms (defined using the step 1 outcome) applied to four months of global data to identify mature algorithms, and (3) a comprehensive validation exercise applied to one complete year of global data produced by the algorithms selected as mature based on the round robin exercise. The algorithms tested included four using AATSR, three using MERIS and one using PARASOL. This paper summarizes the first step. Three experiments were conducted to assess the potential impact of major assumptions in the various aerosol retrieval algorithms. In the first experiment a common set of four aerosol components was used to provide all algorithms with the same assumptions. The second experiment introduced an aerosol property climatology, derived from a combination of model and sun photometer observations, as a priori information in the retrievals on the occurrence of the common aerosol components and their mixing ratios. The third experiment assessed the impact of using a common nadir cloud mask for AATSR and MERIS algorithms in order to characterize the sensitivity to remaining cloud contamination in the retrievals against the baseline dataset versions. The impact of the algorithm changes was assessed for one month (September 2008) of data qualitatively by visible analysis of monthly mean AOD maps and quantitatively by comparing global daily gridded satellite data against daily

  1. Aerosol Characterization Data from the Asian Pacific Regional Aerosol Characterization Project (ACE-Asia)

    DOE Data Explorer

    The Aerosol Characterization Experiments (ACE) were designed to increase understanding of how atmospheric aerosol particles affect the Earth's climate system. These experiments integrated in-situ measurements, satellite observations, and models to reduce the uncertainty in calculations of the climate forcing due to aerosol particles and improve the ability of models to predict the influences of aerosols on the Earth's radiation balance. ACE-Asia was the fourth in a series of experiments organized by the International Global Atmospheric Chemistry (IGAC) Program (A Core Project of the International Geosphere Biosphere Program). The Intensive Field Phase for ACE-Asia took place during the spring of 2001 (mid-March through early May) off the coast of China, Japan and Korea. ACE-Asia pursued three specific objectives: 1) Determine the physical, chemical, and radiative properties of the major aerosol types in the Eastern Asia and Northwest Pacific region and investigate the relationships among these properties. 2) Quantify the physical and chemical processes controlling the evolution of the major aerosol types and in particular their physical, chemical, and radiative properties. 3) Develop procedures to extrapolate aerosol properties and processes from local to regional and global scales, and assess the regional direct and indirect radiative forcing by aerosols in the Eastern Asia and Northwest Pacific region [Edited and shortened version of summary at http://data.eol.ucar.edu/codiac/projs?ACE-ASIA]. The Ace-Asia collection contains 174 datasets.

  2. Aerosol retrieval experiments in the ESA Aerosol_cci project

    NASA Astrophysics Data System (ADS)

    Holzer-Popp, T.; de Leeuw, G.; Griesfeller, J.; Martynenko, D.; Klüser, L.; Bevan, S.; Davies, W.; Ducos, F.; Deuzé, J. L.; Graigner, R. G.; Heckel, A.; von Hoyningen-Hüne, W.; Kolmonen, P.; Litvinov, P.; North, P.; Poulsen, C. A.; Ramon, D.; Siddans, R.; Sogacheva, L.; Tanre, D.; Thomas, G. E.; Vountas, M.; Descloitres, J.; Griesfeller, J.; Kinne, S.; Schulz, M.; Pinnock, S.

    2013-08-01

    Within the ESA Climate Change Initiative (CCI) project Aerosol_cci (2010-2013), algorithms for the production of long-term total column aerosol optical depth (AOD) datasets from European Earth Observation sensors are developed. Starting with eight existing pre-cursor algorithms three analysis steps are conducted to improve and qualify the algorithms: (1) a series of experiments applied to one month of global data to understand several major sensitivities to assumptions needed due to the ill-posed nature of the underlying inversion problem, (2) a round robin exercise of "best" versions of each of these algorithms (defined using the step 1 outcome) applied to four months of global data to identify mature algorithms, and (3) a comprehensive validation exercise applied to one complete year of global data produced by the algorithms selected as mature based on the round robin exercise. The algorithms tested included four using AATSR, three using MERIS and one using PARASOL. This paper summarizes the first step. Three experiments were conducted to assess the potential impact of major assumptions in the various aerosol retrieval algorithms. In the first experiment a common set of four aerosol components was used to provide all algorithms with the same assumptions. The second experiment introduced an aerosol property climatology, derived from a combination of model and sun photometer observations, as a priori information in the retrievals on the occurrence of the common aerosol components. The third experiment assessed the impact of using a common nadir cloud mask for AATSR and MERIS algorithms in order to characterize the sensitivity to remaining cloud contamination in the retrievals against the baseline dataset versions. The impact of the algorithm changes was assessed for one month (September 2008) of data: qualitatively by inspection of monthly mean AOD maps and quantitatively by comparing daily gridded satellite data against daily averaged AERONET sun photometer

  3. Day and night characterization of smoke aerosols during the BORTAS experiment

    NASA Astrophysics Data System (ADS)

    Saha, Auromeet; Baibakov, Konstantin; Blanchard, Yann; Ivanescu, Liviu; O'Neill, Norman T.; Daou, David; Duck, Thomas J.; Strawbridge, Kevin S.

    2013-04-01

    During the summer of 2011 the BORTAS (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) field campaign was carried out over eastern Canada and the western Atlantic. Both passive and active optical measurements were carried out at Halifax, NS using ground-based sun/star photometry and backscatter (Raman) lidar. We employed these ground-based measurements along with supporting information such as CALIPSO (satellite based) lidar profiles, MODIS imagery, chemical transport modeling and backtrajectories to characterize the day / night transition of smoke plumes over Halifax during an extended series of smoke events that lasted from July 17 to 26 (traceable to forest fires in western Ontario). Preliminary analysis indicates a physical coherence between these diverse data elements including day / night continuity of the submicron (smoke) optical depths derived from the sun and star photometer spectra and covariance between the passively derived optical depths and those from the Raman lidar.

  4. Carbonaceous aerosols over the Indian Ocean during the Indian Ocean Experiment (INDOEX): Chemical characterization, optical properties, and probable sources

    NASA Astrophysics Data System (ADS)

    Mayol-Bracero, O. L.; Gabriel, R.; Andreae, M. O.; Kirchstetter, T. W.; Novakov, T.; Ogren, J.; Sheridan, P.; Streets, D. G.

    2002-10-01

    We measured carbonaceous material and water-soluble ionic species in the fine fraction (Dp < 1.3 μm) of aerosol samples collected on NCAR's C-130 aircraft during the intensive field phase (February-March 1999) of the Indian Ocean Experiment (INDOEX). Polluted layers were present over most of the study region north of the equator at altitudes up to 3.2 km. The estimated aerosol mass (sum of carbonaceous and soluble ionic aerosol components) of fine-mode particles in these layers was 15.3 ± 7.9 μg m-3. The major components were particulate organic matter (POM, 35%), SO42- (34%), black carbon (BC, 14%), and NH4+ (11%). The main difference between the composition of the marine boundary layer (MBL, 0 to ˜1.2 km), and the overlying residual continental boundary layer (1.2 to ˜3.2 km) was a higher abundance of SO42- relative to POM in the MBL, probably due to a faster conversion of SO2 into SO42- in the MBL. Our results show that carbon is a major, and sometimes dominant, contributor to the aerosol mass and that its contribution increases with altitude. Low variability was observed in the optical properties of the aerosol in the two layers. Regression analysis of the absorption coefficient at 565 nm on BC mass (BC < 4.0 μg C m-3) yielded a specific absorption cross section of 8.1 ± 0.7 m2 g-1 for the whole period. The unusually high fraction of BC and the good correlation between the absorption coefficient and BC suggest that BC was responsible for the strong light absorption observed for the polluted layers during INDOEX. High correlation between BC and total carbon (TC) (r2 = 0.86) suggest that TC is predominantly of primary origin. Good correlations were also found between the scattering coefficient at 550 nm and the estimated aerosol mass for the fine fraction. These yielded a specific scattering cross section of 4.9 ± 0.4 m2 g-1. The observed BC/TC, BC/OC, SO42-/BC, and K+/BC ratios were fairly constant throughout the period. These ratios suggest that between

  5. Single-particle characterization of atmospheric aerosols collected at Gosan, Korea, during the Asian Pacific Regional Aerosol Characterization Experiment field campaign using low-Z (atomic number) particle electron probe X-ray microanalysis.

    PubMed

    Geng, Hong; Cheng, Fangqin; Ro, Chul-Un

    2011-11-01

    A quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), namely low-Z (atomic number) particle EPMA, was used to characterize the chemical compositions of the individual aerosol particles collected at the Gosan supersite, Jeju Island, Korea, as a part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). On 4-10 April 2001 just before a severe dust storm arrived, seven sets of aerosol samples were obtained by a seven-stage May cascade impactor with a flow rate of 20 L/min. Overall 11,200 particles on stages 1-6 with cutoff diameters of 16, 8, 4, 2, 1, and 0.5 microm, respectively, were examined and classified based on their secondary electron images and X-ray spectra. In general, sea salt particles were the most frequently encountered, followed by mineral dust, organic carbon (OC)-like, (NH4)2SO4/NH4HSO4-containing, elemental carbon (EC)-like, Fe-rich, and K-rich particles. Sea salt and mineral dust particles had a higher relative abundance on stages 1-5, whereas OC-like, (NH4)2SO4/NH4HSO4-containing, Fe-rich, and K-rich particles were relatively abundant on stage 6. The analysis on relative number abundances of various particle types combined with 72-hr backward air mass trajectories indicated that a lot of reacted sea salt and reacted mineral dust (with airborne NOx and SO2 or their acidic products) and OC-like particles were carried by the air masses passing over the Yellow Sea (for sample "10 April") and many NH4HSO4/ (NH4)2SO4-containing particles were carried by the air masses passing over the Sea of Japan and Korea Strait (for samples "4-9 April"). It was concluded that the atmosphere over Jeju Island was influenced by anthropogenic SO2 and NOx, organic compounds, and secondary aerosols when Asian dust was absent.

  6. Baseline radon detectors for shipboard use: Development and deployment in the First Aerosol Characterization Experiment (ACE 1)

    NASA Astrophysics Data System (ADS)

    Whittlestone, S.; Zahorowski, W.

    1998-01-01

    A new design of two-filter radon detector has been developed for measurement of extremely low levels of radon in the harsh environments on board ships and remote islands. These were needed for the First Aerosol Characterization (ACE 1) multiplatform experiment in the Southern Ocean. By employing an internal recirculation system and a wire mesh screen as the second filter it has been possible to reduce the power consumption by as much as a factor of 10 and the weight and cost by a factor of 2 compared to current designs of comparable sensitivity. A very high efficiency of 0.38 count s-1 Bq-1 radon in the instrument has been achieved by counting while sampling. This is a key parameter because the larger this number, the smaller the volume and power consumption of the detector. Two air flow paths are used to separate the high flow rate needed to prevent loss of radon daughters to the walls of the detector and the lower flow rate needed to change the air sample in the instrument. As a result, the inlet air lines and delay chamber needed to remove thoron are compact. With a volume of 750 L the detectors used on board ships for ACE 1 had a sensitivity of about 0.2 counts s-1 Bq-1 m-3 and a lower limit of detection of 40 mBq m-3 for a 1 hour count. An instrument with a volume of 10 m3 and incorporating improvements made since ACE 1 could be expected to have sensitivity of 3.7 c s-1 Bq-1 m-3 and a lower limit of detection of 2 mBq m-3. At 45 min the time resolution is twice as good as that of instruments using a low internal flow rate, but not as good as instruments with a moving filter, where the sampling period is precisely defined. Dual-flow loop radon detectors with screens have the virtues of simplicity and freedom from routine maintenance. This new technology extends the range of sites at which baseline radon measurements can be made to remote areas with little regular technical support and a harsh environment.

  7. Physical characterization of incense aerosols.

    PubMed

    Mannix, R C; Nguyen, K P; Tan, E W; Ho, E E; Phalen, R F

    1996-12-20

    Experiments were performed to study the physical characteristics of smoke aerosols generated by burning three types of stick incense in a 4 m3 clean room. Sidestream cigarette smoke was also examined under the same conditions to provide a comparison. Among the parameters measured were (a) masses of aerosol, carbon monoxide and nitrogen oxides generated by burning the incense or cigarettes, (b) rates of decay of the particles from the air, and (c) estimates of count median particle size during a 7 h period post-burning. There was variability among the types of incense studied with respect to many of the parameters. Also, as a general trend, the greater the initial particulate mass concentration, the more rapid the rate of decay of the smoke. In relation to the quantity of particulate generated, cigarette smoke was found to produce proportionally larger quantities of carbon monoxide and nitrogen oxides than did incense. Due to the fact that burning incense was found to generate large quantities of particulate (an average of greater than 45 mg/g burned, as opposed to about 10 mg/g burned for the cigarettes), it is likely, in cases in which incense is habitually burned in indoor settings, that such a practice would produce substantial airborne particulate concentrations.

  8. Chemical characterization of secondary organic aerosol constituents from isoprene ozonolysis in the presence of acidic aerosol

    NASA Astrophysics Data System (ADS)

    Riva, Matthieu; Budisulistiorini, Sri Hapsari; Zhang, Zhenfa; Gold, Avram; Surratt, Jason D.

    2016-04-01

    Isoprene is the most abundant non-methane hydrocarbon emitted into Earth's atmosphere and is predominantly derived from terrestrial vegetation. Prior studies have focused largely on the hydroxyl (OH) radical-initiated oxidation of isoprene and have demonstrated that highly oxidized compounds, such as isoprene-derived epoxides, enhance the formation of secondary organic aerosol (SOA) through heterogeneous (multiphase) reactions on acidified sulfate aerosol. However, studies on the impact of acidified sulfate aerosol on SOA formation from isoprene ozonolysis are lacking and the current work systematically examines this reaction. SOA was generated in an indoor smog chamber from isoprene ozonolysis under dark conditions in the presence of non-acidified or acidified sulfate seed aerosol. The effect of OH radicals on SOA chemical composition was investigated using diethyl ether as an OH radical scavenger. Aerosols were collected and chemically characterized by ultra performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) and gas chromatography/electron impact ionization-mass spectrometry (GC/EI-MS). Analysis revealed the formation of highly oxidized compounds, including organosulfates (OSs) and 2-methylterols, which were significantly enhanced in the presence of acidified sulfate seed aerosol. OSs identified in the chamber experiments were also observed and quantified in summertime fine aerosol collected from two rural locations in the southeastern United States during the 2013 Southern Oxidant and Aerosol Study (SOAS).

  9. Characterization of Cooking-Related Aerosols

    NASA Astrophysics Data System (ADS)

    Niedziela, R. F.; Blanc, L. E.

    2010-12-01

    The temperatures at which food is cooked are usually high enough to drive oils and other organic compounds out of materials which are being prepared for consumption. As these compounds move away from the hot cooking surface and into the atmosphere, they can participate in chemical reactions or condense to form particles. Given the high concentration of cooking in urban areas, cooking-related aerosols likely contribute to the overall amount of particulate matter on a local scale. Reported here are results for the mid-infrared optical characterization of aerosols formed during the cooking of several meat and vegetable samples in an inert atmosphere. The samples were heated in a novel aerosol generator that is designed to collect particles formed immediately above the cooking surface and inject them into a laminar aerosol flow cell. Preliminary results for the chemical processing of cooking-related aerosols in synthetic air will also be presented.

  10. Apparatus for sampling and characterizing aerosols

    DOEpatents

    Dunn, P.F.; Herceg, J.E.; Klocksieben, R.H.

    1984-04-11

    Apparatus for sampling and characterizing aerosols having a wide particle size range at relatively low velocities may comprise a chamber having an inlet and an outlet, the chamber including: a plurality of vertically stacked, successive particle collection stages; each collection stage includes a separator plate and a channel guide mounted transverse to the separator plate, defining a labyrinthine flow path across the collection stage. An opening in each separator plate provides a path for the aerosols from one collection stage t

  11. Characterization of aerosols containing microcystin.

    PubMed

    Cheng, Yung Sung; Zhou, Yue; Irvin, C Mitch; Kirkpatrick, Barbara; Backer, Lorraine C

    2007-01-01

    Toxic blooms of cyanobacteria are ubiquitous in both freshwater and brackish water sources throughout the world. One class of cyanobacterial toxins, called microcystins, is cyclic peptides. In addition to ingestion and dermal, inhalation is a likely route of human exposure. A significant increase in reporting of minor symptoms, particularly respiratory symptoms was associated with exposure to higher levels of cyanobacteria during recreational activities. Algae cells, bacteria, and waterborne toxins can be aerosolized by a bubble-bursting process with a wind-driven white-capped wave mechanism. The purposes of this study were to: evaluate sampling and analysis techniques for microcystin aerosol, produce aerosol droplets containing microcystin in the laboratory, and deploy the sampling instruments in field studies. A high-volume impactor and an IOM filter sampler were tried first in the laboratory to collect droplets containing microcystins. Samples were extracted and analyzed for microcystin using an ELISA method. The laboratory study showed that cyanotoxins in water could be transferred to air via a bubble-bursting process. The droplets containing microcystins showed a bimodal size distribution with the mass median aerodynamic diameter (MMAD) of 1.4 and 27.8 mum. The sampling and analysis methods were successfully used in a pilot field study to measure microcystin aerosol in situ. PMID:18463733

  12. Copper oxide aerosol: generation and characterization.

    PubMed

    Peoples, S M; McCarthy, J F; Chen, L C; Eppelsheimer, D; Amdur, M O

    1988-06-01

    Effluent gases from high temperature systems such as fossil fuel combustion and pyrometallurgical processes contain inorganic material which has the potential to interact with sulfur dioxide (SO2) on the surface of particles to form an irritant aerosol. The submicron fraction of this inorganic material is especially important as the fine particles may penetrate deep into the lung and cause serious health effects. A laboratory furnace was designed to produce a submicrometer copper oxide aerosol to stimulate emissions from copper smelters and other pyrometallurgical operations. The ultimate aim of this research is to investigate the interaction of SO2 and the copper oxide aerosol at different temperatures and humidities in order to determine the reaction products and their potential health effects upon inhalation. The initial work, as presented in this paper, was to reproducibly generate a submicrometer copper oxide aerosol and to characterize it in terms of size, morphology and composition. Two experimental regimes were set up. One admitted filtered air, without water vapor, into the furnace, and the other admitted filtered air and water vapor. The size and morphology of the aerosols were determined using an electrical aerosol analyzer and transmission electron microscopy. The particles appear as chain aggregates with a count median diameter of 0.026 micron when no water vapor was added and 0.031 micron when water vapor was added into the furnace. Composition of the aerosol was determined using x-ray photoelectron spectroscopy. The aerosol, with or without water in the furnace, consists of a mixture of copper(I) oxide and copper(II) hydroxide. PMID:3400592

  13. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    SciTech Connect

    Davidovits, Paul

    2015-10-20

    Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

  14. Apparatus for sampling and characterizing aerosols

    DOEpatents

    Dunn, Patrick F.; Herceg, Joseph E.; Klocksieben, Robert H.

    1986-01-01

    Apparatus for sampling and characterizing aerosols having a wide particle size range at relatively low velocities may comprise a chamber having an inlet and an outlet, the chamber including: a plurality of vertically stacked, successive particle collection stages; each collection stage includes a separator plate and a channel guide mounted transverse to the separator plate, defining a labyrinthine flow path across the collection stage. An opening in each separator plate provides a path for the aerosols from one collection stage to the next. Mounted within each collection stage are one or more particle collection frames.

  15. Preparation and characterization of magnetizable aerosols.

    PubMed

    Baumann, Romy; Glöckl, Gunnar; Nagel, Stefan; Weitschies, Werner

    2012-04-11

    Magnetizable aerosols can be used for inhalative magnetic drug targeting in order to enhance the drug concentration at a certain target site within the lung. The aim of the present study was to clarify how a typical ferrofluid can be atomized in a reproducible way. The influence of the atomization principle, the concentration of magnetic nanoparticles within the carrier liquid and the addition of commonly used pharmaceutical excipients on the aerosol droplet size were investigated. Iron oxide (magnetite) nanoparticles were synthesized by alkaline precipitation of mixtures of iron(II)- and iron(III)-chloride and coated with citric acid. The resulting ferrofluid was characterized by photon correlation spectroscopy and vibrating sample magnetometry. Two different nebulizers (Pari Boy and eFlow) with different atomization principles were used to generate ferrofluid aerosols. A range of substances that influence the surface tension, viscosity, density or vapor pressure of the ferrofluid were added to investigate their impact on the generated aerosol droplets. The particle size was determined by laser diffraction. A stable ferrofluid with a magnetic core diameter of 10.7 ± 0.45 nm and a hydrodynamic diameter of 124 nm was nebulized by Pari Boy and eFlow. The aerosol droplet size of Pari Boy was approximately 2.5 μm and remained unaffected by the addition of substances that changed the physical properties of the solvent. The droplet size of aerosols generated by eFlow was approximately 5 μm. It was significantly reduced by the addition of Cremophor RH 40, glycerol, polyvinyl pyrrolidone and ethanol. PMID:22306649

  16. Characterizing the long-range transport of black carbon aerosols during Transport and Chemical Evolution over the Pacific (TRACE-P) experiment.

    PubMed

    Verma, Sunita; Worden, John; Payra, Swagata; Jourdain, Line; Shim, Changsub

    2009-07-01

    A major aircraft experiment Transport and Chemical Evolution over the Pacific (TRACE-P) mission over the NW Pacific in March-April 2001 was conducted to better understand how outflow from the Asian continent affects the composition of the global atmosphere. In this paper, a global climate model, GEOS-Chem is used to investigate possible black carbon aerosol contributions from TRACE-P region. Our result depicts that absorbing black carbon ("soot") significantly outflow during lifting to the free troposphere through warm conveyor belt and convection associated with this lifting. The GEOS-Chem simulation results show significant transport of black carbon aerosols from Asian regions to the Western Pacific region during the spring season. As estimated by GEOS-Chem simulations, approximately 25% of the black carbon concentrations over the western pacific originate from SE Asia in the spring.

  17. Ganges Valley Aerosol Experiment: Science and Operations Plan

    SciTech Connect

    Kotamarthi, VR

    2010-06-21

    The Ganges Valley region is one of the largest and most rapidly developing sections of the Indian subcontinent. The Ganges River, which provides the region with water needed for sustaining life, is fed primarily by snow and rainfall associated with Indian summer monsoons. Impacts of changes in precipitation patterns, temperature, and the flow of the snow-fed rivers can be immense. Recent satellite-based measurements have indicated that the upper Ganges Valley has some of the highest persistently observed aerosol optical depth values. The aerosol layer covers a vast region, extending across the Indo-Gangetic Plain to the Bay of Bengal during the winter and early spring of each year. The persistent winter fog in the region is already a cause of much concern, and several studies have been proposed to understand the economic, scientific, and societal dimensions of this problem. During the INDian Ocean EXperiment (INDOEX) field studies, aerosols from this region were shown to affect cloud formation and monsoon activity over the Indian Ocean. This is one of the few regions showing a trend toward increasing surface dimming and enhanced mid-tropospheric warming. Increasing air pollution over this region could modify the radiative balance through direct, indirect, and semi-indirect effects associated with aerosols. The consequences of aerosols and associated pollution for surface insolation over the Ganges Valley and monsoons, in particular, are not well understood. The proposed field study is designed for use of (1) the ARM Mobile Facility (AMF) to measure relevant radiative, cloud, convection, and aerosol optical characteristics over mainland India during an extended period of 9–12 months and (2) the G-1 aircraft and surface sites to measure relevant aerosol chemical, physical, and optical characteristics in the Ganges Valley during a period of 6–12 weeks. The aerosols in this region have complex sources, including burning of coal, biomass, and biofuels; automobile

  18. OMPS LP Characterization of Stratospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Taha, G.; Bhartia, P. K.; Xu, P.; Loughman, R. P.; Jaross, G. R.; DeLand, M. T.; Colarco, P. R.; Aquila, V.

    2015-12-01

    The Suomi NPP OMPS Limb Profiler (LP) collects limb scattered radiance data over a wide spectral range (290-1000 nm) and altitude range (0-80 km). Retrieval of aerosol extinction coefficient profiles from these measurements is complicated by the need to specify particle size distribution and composition, which may vary along a single orbit, as well as on time scales ranging from hours to months. We have developed a radiance-based product, called the Aerosol Scattering Index (ASI), that allows us to characterize many aspects of stratospheric aerosol behavior directly from LP measurements. ASI data clearly demonstrate seasonal changes in the Junge layer that vary with both altitude and latitude. The ASI data can identify volcanic plumes shortly after an eruption, and track the evolution of these plumes over weeks and months. The LP ASI product shows that polar mesospheric clouds (PMCs), although located at 80-85 km during summer months, can affect LP observations and ozone retrievals down to much lower altitudes. Short-lived phenomena such as bolide plumes and rocket exhaust trails are also captured by this product, providing unique information about perturbations in the stratosphere and mesosphere.

  19. SAGE II inversion algorithm. [Stratospheric Aerosol and Gas Experiment

    NASA Technical Reports Server (NTRS)

    Chu, W. P.; Mccormick, M. P.; Lenoble, J.; Brogniez, C.; Pruvost, P.

    1989-01-01

    The operational Stratospheric Aerosol and Gas Experiment II multichannel data inversion algorithm is described. Aerosol and ozone retrievals obtained with the algorithm are discussed. The algorithm is compared to an independently developed algorithm (Lenoble, 1989), showing that the inverted aerosol and ozone profiles from the two algorithms are similar within their respective uncertainties.

  20. Cloud and Aerosol Characterization During CAEsAR 2014

    NASA Astrophysics Data System (ADS)

    Zieger, P.; Tesche, M.; Krejci, R.; Baumgardner, D.; Walther, A.; Rosati, B.; Widequist, U.; Tunved, P.; O'Connor, E.; Ström, J.

    2015-12-01

    The Cloud and Aerosol Experiment at Åre (CAEsAR 2014) campaign took place from June to October 2014 at Mt. Åreskutan, Sweden, a remote mountain site in Northern Sweden. The campaign was designed to study the physical and chemical properties of clouds and aerosols under orographic forcing. A unique and comprehensive set-up allowed an in-situ characterization of both constituents at a mountain top station at 1200 m a.s.l. including instruments to measure cloud droplet size distribution, meteorological parameters, cloud residual properties (using a counterflow virtual impactor inlet), cloud water composition and various aerosol chemical and microphysical properties (e.g. size, optical and hygroscopic properties). At the same time, a remote sensing site was installed below the mountain site at 420 m a.s.l. in the immediate vicinity (< 3 km horizontally), with vertical profiling from an aerosol lidar, winds and turbulence from a scanning Doppler lidar, a Sun photometer measuring aerosol columnar optical properties, and a precipitation sampler taking rain water for chemical analysis. In addition, regular radiosoundings were performed from the valley. Here, we present the results of this intensive campaign which includes approx. 900 hours of in-cloud sampling. Various unique cloud features were frequently observed such as dynamically-driven droplet growth, bimodal droplet distributions, and the activation of particles down to approx. 20 nm in dry particle diameter. During the campaign, a forest fire smoke plume was transported over the site with measureable impacts on the cloud properties. This data will be used to constrain cloud and aerosol models, as well as to validate satellite retrievals. A first comparison to VIIRS and MODIS satellite retrievals will also be shown.

  1. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration.

    PubMed

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H; Henry, Mike; Baden, Daniel G

    2010-05-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5-10 microg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m(3). The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction.

  2. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration

    PubMed Central

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H.; Henry, Mike; Baden, Daniel G.

    2009-01-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1 h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5–10 μg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m3. The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction. PMID:19879288

  3. Characterizing the formation of secondary organic aerosols

    SciTech Connect

    Lunden, Melissa; Black, Douglas; Brown, Nancy

    2004-02-01

    concentrations of important gas phase nitrogen compounds. Experiments have been ongoing at the Blodgett field site since the fall of 2000, and have included portions of the summer and fall of 2001, 2002, and 2003. Analysis of both the gas and particle phase data from the year 2000 show that the particle loading at the site correlates with both biogenic precursors emitted in the forest and anthropogenic precursors advected to the site from Sacramento and the Central Valley of California. Thus the particles at the site are affected by biogenic processing of anthropogenic emissions. Size distribution measurements show that the aerosol at the site has a geometric median diameter of approximately 100 nm. On many days, in the early afternoon, growth of nuclei mode particles (<20 nm) is also observed. These growth events tend to occur on days with lower average temperatures, but are observed throughout the summer. Analysis of the size resolved data for these growth events, combined with typical measured terpene emissions, show that the particle mass measured in these nuclei mode particles could come from oxidation products of biogenic emissions, and can serve as a significant route for SOA partitioning into the particle phase. During periods of each year, the effect of emissions for forest fires can be detected at the Blodgett field location. During the summer of 2002 emissions from the Biscuit fire, a large fire located in Southwest Oregon, was detected in the aerosol data. The results show that increases in particle scattering can be directly related to increased black carbon concentration and an appearance of a larger mode in the aerosol size distribution. These results show that emissions from fires can have significant impact on visibility over large distances. The results also reinforce the view that forest fires can be a significant source of black carbon in the atmosphere, which has important climate and visibility. Continuing work with the 2002 data set, particularly the

  4. Generation and characterization of biological aerosols for laser measurements

    SciTech Connect

    Cheng, Yung-Sung; Barr, E.B.

    1995-12-01

    Concerns for proliferation of biological weapons including bacteria, fungi, and viruses have prompted research and development on methods for the rapid detection of biological aerosols in the field. Real-time instruments that can distinguish biological aerosols from background dust would be especially useful. Sandia National Laboratories (SNL) is developing a laser-based, real-time instrument for rapid detection of biological aerosols, and ITRI is working with SNL scientists and engineers to evaluate this technology for a wide range of biological aerosols. This paper describes methods being used to generate the characterize the biological aerosols for these tests. In summary, a biosafe system has been developed for generating and characterizing biological aerosols and using those aerosols to test the SNL laser-based real-time instrument. Such tests are essential in studying methods for rapid detection of airborne biological materials.

  5. Aerosol characterization of nebulized intranasal glucocorticoid formulations.

    PubMed

    Berlinski, A; Waldrep, J C

    2001-01-01

    Inhaled glucocorticoids (GCs) are the mainstay of long-term therapy for asthma. The lack of suitable preparations in the United States has induced clinicians to use intranasal (IN) GC formulations as "nebulizer suspensions" for off-label therapy. However, no data are available regarding aerosol production and characteristics. The aim of this study was to characterize drug outputs and aerodynamic profiles of four nebulized IN GC formulations with further analysis of flunisolide (Flu), and to test the influence of different delivery system/formulation combinations. The aerodynamic profiles and drug outputs were determined by impaction and chemical analysis. The solution output was determined by the gravimetric technique. Triamcinole acetonide (TAA), fluticasone propionate (Flut), beclomethasone dipropionate (Bec), and Flu (550, 500, 840, and 250 microg, respectively) diluted to 4 mL with saline solution were tested with the Sidestream (SID) and Aero-Tech II (AT2) nebulizers. Subsequently, Flu was tested with four additional nebulizers (Pari LC + [PARI] Acorn II, Hudson T Up-draft II, and Raindrop). All the aerosols were heterodisperse and had a particle size range optimal for peripheral airway deposition (1.85 to 3.67 microm). Flu had the highest drug output in the respirable range (22.8 and 20.3 microg/min with the AT and SID, respectively). Flu was 5-11 times more efficiently nebulized than the other formulations tested. No differences were detected in the solution outputs (0.25 to 0.3 mL/min). In subsequent testing of Flu, the PARI, AT, and SID showed the best performances. The LC+ achieved the highest drug and solution output (27.4 microg/min and 0.89 mL/min, respectively). In conclusion, Flu showed the best aerosol performance characteristics. These data do not endorse the off-label utilization of nebulized IN GC, but underscores the importance of in vitro testing before selecting any formulation/nebulizer combinations for clinical use.

  6. An overview of the Ice Nuclei Research Unit Jungfraujoch/Cloud and Aerosol Characterization Experiment 2013 (INUIT-JFJ/CLACE-2013)

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes

    2014-05-01

    Ice formation in mixed phase tropospheric clouds is an essential prerequisite for the formation of precipitation at mid-latitudes. Ice formation at temperatures warmer than -35°C is only possible via heterogeneous ice nucleation, but up to now the exact pathways of heterogeneous ice formation are not sufficiently well understood. The research unit INUIT (Ice NUcleation research unIT), funded by the Deutsche Forschungsgemeinschaft (DFG FOR 1525) has been established in 2012 with the objective to investigate heterogeneous ice nucleation by combination of laboratory studies, model calculation and field experiments. The main field campaign of the INUIT project (INUIT-JFJ) was conducted at the High Alpine Research Station Jungfraujoch (Swiss Alps, 3580 m asl) during January and February 2013, in collaboration with several international partners in the framework of CLACE2013. The instrumentation included a large set of aerosol chemical and physical analysis instruments (particle counters, particle sizers, particle mass spectrometers, cloud condensation nuclei counters, ice nucleus counters etc.), that were operated inside the Sphinx laboratory and sampled in mixed phase clouds through two ice selective inlets (Ice-CVI, ISI) as well as through a total aerosol inlet that was used for out-of-cloud aerosol measurements. Besides the on-line measurements, also samples for off-line analysis (ESEM, STXM) have been taken in and out of clouds. Furthermore, several cloud microphysics instruments were operated outside the Sphinx laboratory. First results indicate that a large fraction of ice residues sampled from mixed phase clouds contain organic material, but also mineral dust. Soot and lead were not found to be enriched in ice residues. The concentration of heterogeneous ice nuclei was found to be variable (ranging between < 1 and > 100 per liter) and to be strongly dependent on the operating conditions of the respective IN counter. The number size distribution of ice residues

  7. Optical and Chemical Characterization of Aerosols Produced from Cooked Meats

    NASA Astrophysics Data System (ADS)

    Niedziela, R. F.; Foreman, E.; Blanc, L. E.

    2011-12-01

    Cooking processes can release a variety compounds into the air immediately above a cooking surface. The distribution of compounds will largely depend on the type of food that is being processed and the temperatures at which the food is prepared. High temperatures release compounds from foods like meats and carry them away from the preparation surface into cooler regions where condensation into particles can occur. Aerosols formed in this manner can impact air quality, particularly in urban areas where the amount of food preparation is high. Reported here are the results of laboratory experiments designed to optically and chemically characterize aerosols derived from cooking several types of meats including ground beef, salmon, chicken, and pork both in an inert atmosphere and in synthetic air. The laboratory-generated aerosols are studied using a laminar flow cell that is configured to accommodate simultaneous optical characterization in the mid-infrared and collection of particles for subsequent chemical analysis by gas chromatography. Preliminary optical results in the visible and ultra-violet will also be presented.

  8. Subarctic atmospheric aerosol composition: 1. Ambient aerosol characterization

    SciTech Connect

    Friedman, Beth; Herich, Hanna; Kammermann, Lukas; Gross, Deborah S.; Ameth, Almut; Holst, Thomas; Lohmann, U.; Cziczo, Daniel J.

    2009-07-10

    Sub-Arctic aerosol was sampled during July 2007 at the Abisko Research Station Stordalen field site operated by the Royal Swedish Academy of Sciences. Located in northern Sweden at 68º latitude and 385 meters above sea level (msl), this site is classified as a semi-continuous permafrost mire. Number density, size distribution, cloud condensation nucleus properties, and chemical composition of the ambient aerosol were determined. Backtrajectories showed that three distinct airmasses were present over Stordalen during the sampling period. Aerosol properties changed and correlated with airmass origin to the south, northeast, or west. We observe that Arctic aerosol is not compositionally unlike that found in the free troposphere at mid-latitudes. Internal mixtures of sulfates and organics, many on insoluble biomass burning and/or elemental carbon cores, dominate the number density of particles from ~200 to 2000 nm aerodynamic diameter. Mineral dust which had taken up gas phase species was observed in all airmasses. Sea salt, and the extent to which it had lost volatile components, was the aerosol type that most varied with airmass.

  9. A thermoluminescent method for aerosol characterization

    NASA Technical Reports Server (NTRS)

    Long, E. R., Jr.; Rogowski, R. S.

    1976-01-01

    A thermoluminescent method has been used to study the interactions of aerosols with ozone. The preliminary results show that ozone reacts with many compounds found in aerosols, and that the thermoluminescence curves obtained from ozonated aerosols are characteristic of the aerosol. The results suggest several important applications of the thermoluminescent method: development of a detector for identification of effluent sources; a sensitive experimental tool for study of heterogeneous chemistry; evaluation of importance of aerosols in atmospheric chemistry; and study of formation of toxic, electronically excited species in airborne particles.

  10. Characterization of Speciated Aerosol Direct Radiative Forcing Over California

    SciTech Connect

    Zhao, Chun; Leung, Lai-Yung R.; Easter, Richard C.; Hand, Jenny; Avise, J.

    2013-03-16

    A fully coupled meteorology-chemistry model (WRF-Chem) with added capability of diagnosing the spatial and seasonal distribution of radiative forcings for individual aerosol species over California is used to characterize the radiative forcing of speciated aerosols in California. Model simulations for the year of 2005 are evaluated with various observations including meteorological data from California Irrigation Management Information System (CIMIS), aerosol mass concentrations from US EPA Chemical Speciation Network (CSN) and Interagency Monitoring of Protected Visual Environments (IMPROVE), and aerosol optical depth from AErosol RObotic NETwork (AERONET) and satellites. The model well captures the observed seasonal meteorological conditions over California. Overall, the simulation is able to reproduce the observed spatial and seasonal distribution of mass concentration of total PM2.5 and the relative contribution from individual aerosol species, except the model significantly underestimates the surface concentrations of organic matter (OM) and elemental carbon (EC), potentially due to uncertainty in the anthropogenic emissions of OM and EC and the outdated secondary organic aerosol mechanism used in the model. A sensitivity simulation with anthropogenic EC emission doubled significantly reduces the model low bias of EC. The simulation reveals high anthropogenic aerosol loading over the Central Valley and the Los Angeles metropolitan regions and high natural aerosol (dust) loading over southeastern California. The seasonality of aerosol surface concentration is mainly determined by vertical turbulent mixing, ventilation, and photochemical activity, with distinct characteristics for individual aerosol species and between urban and rural areas. The simulations show that anthropogenic aerosols dominate the aerosol optical depth (AOD). The ratio of AOD to AAOD (aerosol absorption optical depth) shows distinct seasonality with a winter maximum and a summer minimum

  11. Characterization of aerosol particles at the forested site in Lithuania

    NASA Astrophysics Data System (ADS)

    Rimselyte, I.; Garbaras, A.; Kvietkus, K.; Remeikis, V.

    2009-04-01

    . Furthermore, we measured TC ^13C/12C isotopic ratio on each cascade. This ratio contributed to identifying sources of carbonaceous species. References Garbaras, A., Andriejauskiene, J., Bariseviciute, R., Remeikis, V., 2008. Tracing of atmospheric aerosol sources using stable carbon isotopes. Lithuanian J. Phys. 48, 259-264. Jaenicke, R., 1998. Atmospheric aerosol size distribution. In: Harrison, R.M., van Grieken, R.E. (Eds.), Atmospheric Particles. John Wiley & Sons, Chichester, pp. 1-28. Middlebrook, A.M., Murphy, D.M., Thomson, D.S., 1998. Observations of organic material in individual marine particles at Cape Grim during the first aerosol characterization experiment (ACE 1). Journal of Geophysical Research 103, 16475-16483. Norman, A.L., Hopper, J.F., Blanchard, P., Ernst, D., Brice, K., Alexandrou, N., Klouda, G., 1999. The stable carbon isotope composition of atmospheric PAHs. Atmospheric Environment 33 (17), 2807-2814. Samara, C., Voutsa, D., 2005. Size distribution of airborne particulate matter and associated heavy metals in the roadside environment. Chemosphere 59, 1197-1206.

  12. São Paulo aerosol characterization study.

    PubMed

    Alonso, C D; Martins, M H; Romano, J; Godinho, R

    1997-12-01

    The São Paulo Metropolitan area (SPMA) is characterized as having one of the worst air pollution problems in Brazil, with frequent violations of air quality standards for particulate matter. This paper presents the results of a receptor model source apportionment study carried out to develop a quantitative database on which a control strategy could be developed. The study was conducted in four sites with distinct land uses. Fine, coarse (CP), and total suspended particles (TSP) samples were collected on Teflon and glass filters and analyzed by x-ray fluorescence (XRF), ion chromatography, and thermal evolution. The sources were characterized by similar methodology. Chemical mass balance (CMB) receptor modeling indicated that carbonaceous material plays an important role in the aerosol composition; that the three major source categories contributing to the fine particles are vehicles, secondary carbon, and sulfates; and that the main contributors to CP and TSP are road dust and vehicles. All sampling sites presented the same general pattern in terms of source contribution, although this contribution varied from site to site.

  13. Detailed Aerosol Characterization using Polarimetric Measurements

    NASA Astrophysics Data System (ADS)

    Hasekamp, Otto; di Noia, Antonio; Stap, Arjen; Rietjens, Jeroen; Smit, Martijn; van Harten, Gerard; Snik, Frans

    2016-04-01

    Anthropogenic aerosols are believed to cause the second most important anthropogenic forcing of climate change after greenhouse gases. In contrast to the climate effect of greenhouse gases, which is understood relatively well, the negative forcing (cooling effect) caused by aerosols represents the largest reported uncertainty in the most recent assessment of the International Panel on Climate Change (IPCC). To reduce the large uncertainty on the aerosol effects on cloud formation and climate, accurate satellite measurements of aerosol optical properties (optical thickness, single scattering albedo, phase function) and microphysical properties (size distribution, refractive index, shape) are essential. There is growing consensus in the aerosol remote sensing community that multi-angle measurements of intensity and polarization are essential to unambiguously determine all relevant aerosol properties. This presentations adresses the different aspects of polarimetric remote sensing of atmospheric aerosols, including retrieval algorithm development, validation, and data needs for climate and air quality applications. During past years, at SRON-Netherlands Instite for Space Research retrieval algorithms have been developed that make full use of the capabilities of polarimetric measurements. We will show results of detailed aerosol properties from ground-based- (groundSPEX), airborne- (NASA Research Scanning Polarimeter), and satellite (POLDER) measurements. Also we will discuss observational needs for future instrumentation in order to improve our understanding of the role of aerosols in climate change and air quality.

  14. Aerosol effects and corrections in the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Hervig, Mark E.; Russell, James M., III; Gordley, Larry L.; Daniels, John; Drayson, S. Roland; Park, Jae H.

    1995-01-01

    The eruptions of Mt. Pinatubo in June 1991 increased stratospheric aerosol loading by a factor of 30, affecting chemistry, radiative transfer, and remote measurements of the stratosphere. The Halogen Occultation Experiment (HALOE) instrument on board Upper Atmosphere Research Satellite (UARS) makes measurements globally for inferring profiles of NO2, H2O, O3, HF, HCl, CH4, NO, and temperature in addition to aerosol extinction at five wavelengths. Understanding and removing the aerosol extinction is essential for obtaining accurate retrievals from the radiometer channels of NO2, H2O and O3 in the lower stratosphere since these measurements are severely affected by contaminant aerosol absorption. If ignored, aerosol absorption in the radiometer measurements is interpreted as additional absorption by the target gas, resulting in anomalously large mixing ratios. To correct the radiometer measurements for aerosol effects, a retrieved aerosol extinction profile is extrapolated to the radiometer wavelengths and then included as continuum attenuation. The sensitivity of the extrapolation to size distribution and composition is small for certain wavelength combinations, reducing the correction uncertainty. The aerosol corrections extend the usable range of profiles retrieved from the radiometer channels to the tropopause with results that agree well with correlative measurements. In situations of heavy aerosol loading, errors due to aerosol in the retrieved mixing ratios are reduced to values of about 15, 25, and 60% in H2O, O3, and NO2, respectively, levels that are much less than the correction magnitude.

  15. Characterization of aerosols produced by surgical procedures

    SciTech Connect

    Yeh, H.C.; Muggenburg, B.A.; Lundgren, D.L.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K.; Turner, R.S.

    1994-07-01

    In many surgeries, especially orthopedic procedures, power tools such as saws and drills are used. These tools may produce aerosolized blood and other biological material from bone and soft tissues. Surgical lasers and electrocautery tools can also produce aerosols when tissues are vaporized and condensed. Studies have been reported in the literature concerning production of aerosols during surgery, and some of these aerosols may contain infectious material. Garden et al. (1988) reported the presence of papilloma virus DNA in the fumes produced from laser surgery, but the infectivity of the aerosol was not assessed. Moon and Nininger (1989) measured the size distribution and production rate of emissions from laser surgery and found that particles were generally less than 0.5 {mu}m diameter. More recently there has been concern expressed over the production of aerosolized blood during surgical procedures that require power tools. In an in vitro study, the production of an aerosol containing the human immunodeficiency virus (HIV) was reported when power tools were used to cut tissues with blood infected with HIV. Another study measured the size distribution of blood aerosols produced by surgical power tools and found blood-containing particles in a number of size ranges. Health care workers are anxious and concerned about whether surgically produced aerosols are inspirable and can contain viable pathogens such as HIV. Other pathogens such as hepatitis B virus (HBV) are also of concern. The Occupational Safety and Health funded a project at the National Institute for Inhalation Toxicology Research Institute to assess the extent of aerosolization of blood and other tissues during surgical procedures. This document reports details of the experimental and sampling approach, methods, analyses, and results on potential production of blood-associated aerosols from surgical procedures in the laboratory and in the hospital surgical suite.

  16. Capstone Depleted Uranium Aerosols: Generation and Characterization

    SciTech Connect

    Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray; Holmes, Tom; Cheng, Yung-Sung; Kenoyer, Judson L.; Collins, John W.; Sanderson, T. Ellory; Fliszar, Richard W.; Gold, Kenneth; Beckman, John C.; Long, Julie

    2004-10-19

    In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

  17. Discrimination of cloud and aerosol in the Stratospheric Aerosol and Gas Experiment III occultation data.

    PubMed

    Kent, G S; Wang, P H; Skeens, K M

    1997-11-20

    The Stratospheric Aerosol and Gas Experiment (SAGE) III, scheduled for a first launch in mid-1998, will be making measurements of the extinction that is due to aerosols and gases at many wavelengths between 385 and 1550 nm. In the troposphere and wintertime polar stratosphere, extinction will also occur because of the presence of cloud along the optical path from the Sun to the satellite instrument. We describe a method for separating the effects of aerosol and cloud using the extinction at 525, 1020, and 1550 nm and present the results of simulation studies. These studies show that the new method will work well under background nonvolcanic aerosol conditions in the upper troposphere and lower stratosphere. Under conditions of severe volcanic contamination, the error rate for the separation of aerosol and cloud may rise as high as 30%.

  18. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, V.; Subramanian, V.; Baskaran, R.; Venkatraman, B.

    2015-07-01

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

  19. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

    SciTech Connect

    Gopalakrishnan, V.; Subramanian, V.; Baskaran, R.; Venkatraman, B.

    2015-07-15

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

  20. Aged organic aerosol in the Eastern Mediterranean: the Finokalia aerosol measurement experiment-2008

    NASA Astrophysics Data System (ADS)

    Hildebrandt, L.; Engelhart, G. J.; Mohr, C.; Kostenidou, E.; Lanz, V. A.; Bougiatioti, A.; Decarlo, P. F.; Prévôt, A. S. H.; Baltensperger, U.; Mihalopoulos, N.; Donahue, N. M.; Pandis, S. N.

    2010-01-01

    Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008), which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS) was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA) with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA) was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with time of day, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm-3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  1. Aged organic aerosol in the Eastern Mediterranean: the Finokalia Aerosol Measurement Experiment - 2008

    NASA Astrophysics Data System (ADS)

    Hildebrandt, L.; Engelhart, G. J.; Mohr, C.; Kostenidou, E.; Lanz, V. A.; Bougiatioti, A.; Decarlo, P. F.; Prevot, A. S. H.; Baltensperger, U.; Mihalopoulos, N.; Donahue, N. M.; Pandis, S. N.

    2010-05-01

    Aged organic aerosol (OA) was measured at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2008 (FAME-2008), which was part of the EUCAARI intensive campaign of May 2008. The site at Finokalia is influenced by air masses from different source regions, including long-range transport of pollution from continental Europe. A quadrupole aerosol mass spectrometer (Q-AMS) was employed to measure the size-resolved chemical composition of non-refractory submicron aerosol (NR-PM1), and to estimate the extent of oxidation of the organic aerosol. Factor analysis was used to gain insights into the processes and sources affecting the OA composition. The particles were internally mixed and liquid. The largest fraction of the dry NR-PM1 sampled was ammonium sulfate and ammonium bisulfate, followed by organics and a small amount of nitrate. The variability in OA composition could be explained with two factors of oxygenated organic aerosol (OOA) with differing extents of oxidation but similar volatility. Hydrocarbon-like organic aerosol (HOA) was not detected. There was no statistically significant diurnal variation in the bulk composition of NR-PM1 such as total sulfate or total organic aerosol concentrations. However, the OA composition exhibited statistically significant diurnal variation with more oxidized OA in the afternoon. The organic aerosol was highly oxidized, regardless of the source region. Total OA concentrations also varied little with source region, suggesting that local sources had only a small effect on OA concentrations measured at Finokalia. The aerosol was transported for about one day before arriving at the site, corresponding to an OH exposure of approximately 4×1011 molecules cm-3 s. The constant extent of oxidation suggests that atmospheric aging results in a highly oxidized OA at these OH exposures, regardless of the aerosol source.

  2. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering. 1992 Annual summary

    SciTech Connect

    Aker, P.M.

    1993-01-30

    This study is aimed at characterizing the influence of aerosol surface structure on the kinetics of gas-aerosol interactions. Changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol are measured with aerosols having different surface properties due to the composition and/or temperature of the material making up the aerosol. The kinetic data generated can be used directly in atmospheric modeling calculations. The surface structure of the aerosol is using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during, the course of the reaction. This dynamics information can be used to generate kinetic data for systems which are similar in nature to those studied, but are not amenable to laboratory investigation. We show here that increased MDSRS sensitivity is achieved by using an excitation laser source that has a narrow linewidth and we have been able to detect sulfate anion concentrations much lower than previously reported. We have shown that the linewidth of the MDSRS mode excited in a droplet is limited by the laser linewidth. This is a positive result for it eases our ability to quantify the MDSRS gain equation. This result also suggests that MDSRS signal size should be independent of droplet size, and preliminary experiments confirm this hypothesis.

  3. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering

    SciTech Connect

    Aker, P.M.

    1993-01-30

    This study is aimed at characterizing the influence of aerosol surface structure on the kinetics of gas-aerosol interactions. Changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol are measured with aerosols having different surface properties due to the composition and/or temperature of the material making up the aerosol. The kinetic data generated can be used directly in atmospheric modeling calculations. The surface structure of the aerosol is using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during, the course of the reaction. This dynamics information can be used to generate kinetic data for systems which are similar in nature to those studied, but are not amenable to laboratory investigation. We show here that increased MDSRS sensitivity is achieved by using an excitation laser source that has a narrow linewidth and we have been able to detect sulfate anion concentrations much lower than previously reported. We have shown that the linewidth of the MDSRS mode excited in a droplet is limited by the laser linewidth. This is a positive result for it eases our ability to quantify the MDSRS gain equation. This result also suggests that MDSRS signal size should be independent of droplet size, and preliminary experiments confirm this hypothesis.

  4. Chemical properties and outflow patterns of anthropogenic and dust particles on Rishiri Island during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia)

    NASA Astrophysics Data System (ADS)

    Matsumoto, Kiyoshi; Uyama, Yukiko; Hayano, Teruaki; Tanimoto, Hiroshi; Uno, Itsushi; Uematsu, Mitsuo

    2003-12-01

    Investigations of chemical properties and transport mechanisms of continental aerosols are necessary for estimating their influences on global radiative budget and on the global material cycle. Intensive measurements of atmospheric aerosols and the associated species on Rishiri Island, near the northern tip of Japan, were conducted from March to May 2001, in order to understand the chemical properties, source regions, transport pathways, and transport patterns of anthropogenic and mineral aerosols over the east Asian Pacific Rim region during the spring. Mean concentrations of nss-SO42-, NO3-, NH4+, nss-Ca2+ in aerosols were 2.48, 0.64, 0.72, and 0.17 μg m-3, respectively. Elemental carbon and organic carbon in fine particles (d < 2.5 μm) yielded mean concentrations of 0.25 and 0.80 μg m-3, respectively. The concentrations of these species frequently increased to higher values because of outbreaks of continental polluted air masses, whereas under background conditions, they decreased to lower values similar to those observed over the remote ocean. Our results demonstrate that nss-SO42- and NH4+ coexist in fine particles, that NO3- and nss-Ca2+ coexist in coarse particles, and that each set is transported in an alternate manner. Continentally derived NO3- is transported as coarse particle to the east Asian Pacific Rim region. Anthropogenic pollutants and dust particles are not necessarily transported together. It was often found that anthropogenic fine particles containing abundant nss-SO42- appeared first and were then followed by large mineral particles that had absorbed NO3-. Short-term intrusion of the air masses containing abundant particulate carbonaceous compounds, probably due to the influence of biomass burning, also often occurred during the outflow events of continental air masses. Atmospheric behaviors of sulfate, nitrate, and carbonaceous species are different from one another, although they are all derived mainly from combustion processes.

  5. Development and Characterization of a Thermodenuder for Aerosol Volatility Measurements

    SciTech Connect

    Dr. Timothy Onasch

    2009-09-09

    This SBIR Phase I project addressed the critical need for improved characterization of carbonaceous aerosol species in the atmosphere. The proposed work focused on the development of a thermodenuder (TD) system capable of systematically measuring volatility profiles of primary and secondary organic aerosol species and providing insight into the effects of absorbing and nonabsorbing organic coatings on particle absorption properties. This work provided the fundamental framework for the generation of essential information needed for improved predictions of ambient aerosol loadings and radiative properties by atmospheric chemistry models. As part of this work, Aerodyne Research, Inc. (ARI) continued to develop and test, with the final objective of commercialization, an improved thermodenuder system that can be used in series with any aerosol instrument or suite of instruments (e.g., aerosol mass spectrometers-AMS, scanning mobility particle sizers-SMPS, photoacoustic absorption spectrometers-PAS, etc.) to obtain aerosol chemical, physical, and optical properties as a function of particle volatility. In particular, we provided the proof of concept for the direct coupling of our improved TD design with a full microphysical model to obtain volatility profiles for different organic aerosol components and to allow for meaningful comparisons between different TD-derived aerosol measurements. In a TD, particles are passed through a heated zone and a denuding (activated charcoal) zone to remove semi-volatile material. Changes in particle size, number concentration, optical absorption, and chemical composition are subsequently detected with aerosol instrumentation. The aerosol volatility profiles provided by the TD will strengthen organic aerosol emission inventories, provide further insight into secondary aerosol formation mechanisms, and provide an important measure of particle absorption (including brown carbon contributions and identification, and absorption enhancements

  6. Apparatus and method for the characterization of respirable aerosols

    DOEpatents

    Clark, Douglas K.; Hodges, Bradley W.; Bush, Jesse D.; Mishima, Jofu

    2016-05-31

    An apparatus for the characterization of respirable aerosols, including: a burn chamber configured to selectively contain a sample that is selectively heated to generate an aerosol; a heating assembly disposed within the burn chamber adjacent to the sample; and a sampling segment coupled to the burn chamber and configured to collect the aerosol such that it may be analyzed. The apparatus also includes an optional sight window disposed in a wall of the burn chamber such that the sample may be viewed during heating. Optionally, the sample includes one of a Lanthanide, an Actinide, and a Transition metal.

  7. The Stratospheric Aerosol and Gas Experiment III - International Space Station: Extending Long-Term Ozone and Aerosol Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Eckman, R.; Zawodny, J. M.; Cisewski, M.; Gasbarre, J.; Flittner, D. E.; Hill, C.; Roell, M.; Moore, J. R.; Hernandez, G.; McCormick, M. P.

    2013-12-01

    The Stratospheric Aerosol and Gas Experiment III - International Space Station (SAGE III on ISS) will extend the global measurements of vertical profiles of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gases begun with SAGE I in 1979, enabling the detection of long-term trends. SAGE III on ISS is the fourth in a series of instruments developed for monitoring these constituents in the stratosphere and troposphere. The SAGE III instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm, using the heritage occultation technique, utilizing both the sun and the moon. Launch to ISS is planned for early 2015 aboard a Falcon 9 spacecraft. SAGE III will investigate the spatial and temporal variability of the measured species in order to determine their role in climatological processes, biogeochemical cycles, the hydrologic cycle, and atmospheric chemistry. It will characterize tropospheric, as well as stratospheric aerosols and upper tropospheric and stratospheric clouds, and investigate their effects on the Earth's environment including radiative, microphysical, and chemical interactions. The multi-decadal SAGE ozone and aerosol data sets have undergone intense scrutiny and are the international standard for accuracy and stability. SAGE data have been used to monitor the effectiveness of the Montreal Protocol. Amongst its key objectives will be to assess the state of the recovery in the distribution of ozone, to reestablish the aerosol measurements needed by both climate and ozone models, and to gain further insight into key processes contributing to ozone and aerosol variability. The ISS is ideal for Earth observing experiments; its mid-inclination orbit allows for a large range in latitude sampling and nearly continuous communications with payloads. In this presentation, we describe the SAGE III on ISS mission, its implementation, current status, and concentrate on its key science objectives.

  8. Comparison of Aerosol Single Scattering Albedos Derived by Diverse Techniques In Two North Atlantic Experiments

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Redemann, J.; Schmid, B.; Bergstrom, R. W.; Livingston, J. M.; McIntosh, D. M.; Ramirez, S. A.; Hartley, S.; Hobbs, P. V.; Quinn, P. K.

    2002-01-01

    Aerosol single scattering albedo omega (the ratio of scattering to extinction) is important in determining aerosol climatic effects, in explaining relationships between calculated and measured radiative fluxes, and in retrieving aerosol optical depths from satellite radiances. Recently, two experiments in the North Atlantic region, the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the Second Aerosol Characterization Experiment (ACE-2), determined aerosol omega by a variety of techniques. The techniques included fitting of calculated to measured radiative fluxes; retrievals of omega from skylight radiances; best fits of complex refractive index to profiles of backscatter extinction, and size distribution; and in situ measurements of scattering and absorption at the surface and aloft. Both TARFOX and ACE-2 found a fairly wide range of values for omega at midvisable wavelengths approx. 550 nm, with omega(sub midvis) greater than or equal to 0.85 and less than or equal to 0.99 for the marine aerosol impacted by continental pollution. Frequency distributions of omega could usually be approximated by lognormals in omega(sub max) - omega, with some occurrence of bimodality, suggesting the influence of different aerosol sources or processing. In both TARFOX and ACE-2, closure tests between measured and calculated radiative fluxes yielded best-fit values of omega(sub midvis) 0.90 +/- 0.04 for the polluted boundary layer. Although these results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and other uncertainties (e.g., thermal offsets, unknown gas absorption) The other techniques gave larger values for omega(sub midvis) for the polluted boundary layer, with a typical result of omega(sub midvis) = 0.95 +/- 0.04. Current uncertainties in omega are large in terms of climate effects More tests are needed of the consistency among different methods and of

  9. A Global Aerosol Model Forecast for the ACE-Asia Field Experiment

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Ginoux, Paul; Lucchesi, Robert; Huebert, Barry; Weber, Rodney; Anderson, Tad; Masonis, Sarah; Blomquist, Byron; Bandy, Alan; Thornton, Donald

    2003-01-01

    We present the results of aerosol forecast during the Aerosol Characterization Experiment (ACE-Asia) field experiment in spring 2001, using the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model and the meteorological forecast fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS). The aerosol model forecast provides direct information on aerosol optical thickness and concentrations, enabling effective flight planning, while feedbacks from measurements constantly evaluate the model, making successful model improvements. We verify the model forecast skill by comparing model predicted total aerosol extinction, dust, sulfate, and SO2 concentrations with those quantities measured by the C-130 aircraft during the ACE-Asia intensive operation period. The GEOS DAS meteorological forecast system shows excellent skills in predicting winds, relative humidity, and temperature for the ACE-Asia experiment area as well as for each individual flight, with skill scores usually above 0.7. The model is also skillful in forecast of pollution aerosols, with most scores above 0.5. The model correctly predicted the dust outbreak events and their trans-Pacific transport, but it constantly missed the high dust concentrations observed in the boundary layer. We attribute this missing dust source to the desertification regions in the Inner Mongolia Province in China, which have developed in recent years but were not included in the model during forecasting. After incorporating the desertification sources, the model is able to reproduce the observed high dust concentrations at low altitudes over the Yellow Sea. Two key elements for a successful aerosol model forecast are correct source locations that determine where the emissions take place, and realistic forecast winds and convection that determine where the aerosols are transported. We demonstrate that our global model can not only account for the large

  10. Study to perform preliminary experiments to evaluate particle generation and characterization techniques for zero-gravity cloud physics experiments

    NASA Technical Reports Server (NTRS)

    Katz, U.

    1982-01-01

    Methods of particle generation and characterization with regard to their applicability for experiments requiring cloud condensation nuclei (CCN) of specified properties were investigated. Since aerosol characterization is a prerequisite to assessing performance of particle generation equipment, techniques for characterizing aerosol were evaluated. Aerosol generation is discussed, and atomizer and photolytic generators including preparation of hydrosols (used with atomizers) and the evaluation of a flight version of an atomizer are studied.

  11. Characterization of biomass burning aerosols from forest fire in Indonesia

    NASA Astrophysics Data System (ADS)

    Fujii, Y.; Iriana, W.; Okumura, M.; Lestari, P.; Tohno, S.; Akira, M.; Okuda, T.

    2012-12-01

    Biomass burning (forest fire, wild fire) is a major source of pollutants, generating an estimate of 104 Tg per year of aerosol particles worldwide. These particles have adverse human health effects and can affect the radiation budget and climate directly and indirectly. Eighty percent of biomass burning aerosols are generated in the tropics and about thirty percent of them originate in the tropical regions of Asia (Andreae, 1991). Several recent studies have reported on the organic compositions of biomass burning aerosols in the tropical regions of South America and Africa, however, there is little data about forest fire aerosols in the tropical regions of Asia. It is important to characterize biomass burning aerosols in the tropical regions of Asia because the aerosol properties vary between fires depending on type and moisture of wood, combustion phase, wind conditions, and several other variables (Reid et al., 2005). We have characterized PM2.5 fractions of biomass burning aerosols emitted from forest fire in Indonesia. During the dry season in 2012, PM2.5 aerosols from several forest fires occurring in Riau, Sumatra, Indonesia were collected on quartz and teflon filters with two mini-volume samplers. Background aerosols in forest were sampled during transition period of rainy season to dry season (baseline period). Samples were analyzed with several analytical instruments. The carbonaceous content (organic and elemental carbon, OC and EC) of the aerosols was analyzed by a thermal optical reflectance technique using IMPROVE protocol. The metal, inorganic ion and organic components of the aerosols were analyzed by X-ray Fluorescence (XRF), ion chromatography and gas chromatography-mass spectrometry, respectively. There was a great difference of chemical composition between forest fire and non-forest fire samples. Smoke aerosols for forest fires events were composed of ~ 45 % OC and ~ 2.5 % EC. On the other hand, background aerosols for baseline periods were

  12. Characterizing the Spatial and Temporal Distribution of Aerosol Optical Thickness Over the Atlantic Basin Utilizing GOES-8 Multispectral Data

    NASA Technical Reports Server (NTRS)

    Fox, Robert; Prins, Elaine Mae; Feltz, Joleen M.

    2001-01-01

    In recent years, modeling and analysis efforts have suggested that the direct and indirect radiative effects of both anthropogenic and natural aerosols play a major role in the radiative balance of the earth and are an important factor in climate change calculations. The direct effects of aerosols on radiation and indirect effects on cloud properties are not well understood at this time. In order to improve the characterization of aerosols within climate models it is important to accurately parameterize aerosol forcing mechanisms at the local, regional, and global scales. This includes gaining information on the spatial and temporal distribution of aerosols, transport regimes and mechanisms, aerosol optical thickness, and size distributions. Although there is an expanding global network of ground measurements of aerosol optical thickness and size distribution at specific locations, satellite data must be utilized to characterize the spatial and temporal extent of aerosols and transport regimes on regional and global scales. This study was part of a collaborative effort to characterize aerosol radiative forcing over the Atlantic basin associated with the following three major aerosol components in this region: urban/sulfate, Saharan dust, and biomass burning. In-situ ground measurements obtained by a network of sun photometers during the Smoke Clouds and Radiation Experiment in Brazil (SCAR-B) and the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) were utilized to develop, calibrate, and validate a Geostationary Operational Environmental Satellite (GOES)-8 aerosol optical thickness (AOT) product. Regional implementation of the GOES-8 AOT product was used to augment point source measurements to gain a better understanding of the spatial and temporal distributions of Atlantic basin aerosols during SCAR-B and TARFOX.

  13. Characterization of aerosols produced by surgical procedures: A summary

    SciTech Connect

    Yeh, Hsu-Chi; Muggenburg, B.A.; Lundgren, D.L.; Turner, R.S.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K.

    1994-11-01

    In many types of surgery, especially orthopedic procedures, power tools such as saws and drills are used. These tools can impart considerable energy in disrupting tissue and may produce aerosolized blood and material from bone and other tissues. Surgical lasers and electrocautery tools can also produce aerosols due to vaporization of blood and tissues. A number of studies have been reported concerning production of aerosols during surgery, and some of the aerosols produced may contain infectious materials. Health care workers have expressed concern and questions pertaining to the occupational transmission of blood-borne pathogens including the human immunodeficiency virus (HIV) and hepatitis B virus (HBV) via blood aerosols during surgery. Little or no data existed characterizing the aerosols produced performing surgical procedures. Because of this lack of data, the National Institute for Occupational Safety and Health funded a project at ITRI to assess the extent of aerosolization of blood and other tissues during surgical procedures in the laboratory and in a hospital surgical suite.

  14. Chemical characterization of organosulfates in secondary organic aerosol derived from the photooxidation of alkanes

    NASA Astrophysics Data System (ADS)

    Riva, Matthieu; Da Silva Barbosa, Thais; Lin, Ying-Hsuan; Stone, Elizabeth A.; Gold, Avram; Surratt, Jason D.

    2016-09-01

    We report the formation of aliphatic organosulfates (OSs) in secondary organic aerosol (SOA) from the photooxidation of C10-C12 alkanes. The results complement those from our laboratories reporting the formation of OSs and sulfonates from gas-phase oxidation of polycyclic aromatic hydrocarbons (PAHs). Both studies strongly support the formation of OSs from the gas-phase oxidation of anthropogenic precursors, as hypothesized on the basis of recent field studies in which aromatic and aliphatic OSs were detected in fine aerosol collected from several major urban locations. In this study, dodecane, cyclodecane and decalin, considered to be important SOA precursors in urban areas, were photochemically oxidized in an outdoor smog chamber in the presence of either non-acidified or acidified ammonium sulfate seed aerosol. Effects of acidity and relative humidity on OS formation were examined. Aerosols collected from all experiments were characterized by ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS). Most of the OSs identified could be explained by formation of gaseous epoxide precursors with subsequent acid-catalyzed reactive uptake onto sulfate aerosol and/or heterogeneous reactions of hydroperoxides. The OSs identified here were also observed and quantified in fine urban aerosol samples collected in Lahore, Pakistan, and Pasadena, CA, USA. Several OSs identified from the photooxidation of decalin and cyclodecane are isobars of known monoterpene organosulfates, and thus care must be taken in the analysis of alkane-derived organosulfates in urban aerosol.

  15. Ganges Valley Aerosol Experiment (GVAX) Final Campaign Report

    SciTech Connect

    Kotamarthi, VR

    2013-12-01

    In general, the Indian Summer Monsoon (ISM) as well as the and the tropical monsoon climate is influenced by a wide range of factors. Under various climate change scenarios, temperatures over land and into the mid troposphere are expected to increase, intensifying the summer pressure gradient differential between land and ocean and thus strengthening the ISM. However, increasing aerosol concentration, air pollution, and deforestation result in changes to surface albedo and insolation, potentially leading to low monsoon rainfall. Clear evidence points to increasing aerosol concentrations over the Indian subcontinent with time, and several hypotheses regarding the effect on monsoons have been offered. The Ganges Valley Aerosol Experiment (GVAX) field study aimed to provide critical data to address these hypotheses and contribute to developing better parameterizations for tropical clouds, convection, and aerosol-cloud interactions. The primary science questions for the mission were as follows:

  16. Results from simulated upper-plenum aerosol transport and aerosol resuspension experiments

    SciTech Connect

    Wright, A.L.; Pattison, W.L.

    1984-01-01

    Recent calculational results published as part of the Battelle-Columbus BMI-2104 source term study indicate that, for some LWR accident sequences, aerosol deposition in the reactor primary coolant system (PCS) can lead to significant reductions in the radionuclide source term. Aerosol transport and deposition in the PCS have been calculated in this study using the TRAP-MELT 2 computer code, which was developed at Battelle-Columbus; the status of validation of the TRAP-MELT 2 code has been described in an Oak Ridge National Laboratory (ORNL) report. The objective of the ORNL TRAP-MELT Validation Project, which is sponsored by the Fuel Systems Behavior Research Branch of the US Nuclear Regulatory Commission, is to conduct simulated reactor-vessel upper-plenum aerosol deposition and transport tests. The results from these tests will be used in the ongoing effort to validate TRAP-MELT 2. The TRAP-MELT Validation Project includes two experimental subtasks. In the Aerosol Transport Tests, aerosol transport in a vertical pipe is being studied; this geometry was chosen to simulate aerosol deposition and transport in the reactor-vessel upper-plenum. To date, four experiments have been performed; the results from these tests are presented in this paper. 7 refs., 4 figs., 4 tabs.

  17. Acidic sulfate aerosols: characterization and exposure.

    PubMed

    Lioy, P J; Waldman, J M

    1989-02-01

    Exposures to acidic aerosol in the atmosphere are calculated from data reported in the scientific literature. The majority of date was not derived from studies necessarily designed to examine human exposures. Most of the studies were designed to investigate the characteristics of the atmosphere. However, the measurements were useful in defining two potential exposure situations: regional stagnation and transport conditions and local plume impacts. Levels of acidic aerosol in excess of 20 to 40 micrograms/m3 (as H2SO4) have been observed for time durations ranging from 1 to 12 hr. These were associated with high, but not necessarily the highest, atmospheric SO4(2)- levels. Exposures of 100 to 900 micrograms/m3/hr were calculated for the acid events that were monitored. In contrast, earlier London studies indicated that apparent acidity in excess of 100 micrograms/m3 (as H2SO4) was present in the atmosphere, and exposures less than 2000 micrograms/m3/hr were possible. Our present knowledge about the frequency, magnitude, and duration of acidic sulfate aerosol events and episodes is insufficient. Efforts must be made to gather more data, but these should be done in such a way that evaluation of human exposure is the focus of the research. In addition, further data are required on the mechanisms of formation of H2SO4 and on what factors can be used to predict acidic sulfate episodes.

  18. Acidic sulfate aerosols: characterization and exposure.

    PubMed Central

    Lioy, P J; Waldman, J M

    1989-01-01

    Exposures to acidic aerosol in the atmosphere are calculated from data reported in the scientific literature. The majority of date was not derived from studies necessarily designed to examine human exposures. Most of the studies were designed to investigate the characteristics of the atmosphere. However, the measurements were useful in defining two potential exposure situations: regional stagnation and transport conditions and local plume impacts. Levels of acidic aerosol in excess of 20 to 40 micrograms/m3 (as H2SO4) have been observed for time durations ranging from 1 to 12 hr. These were associated with high, but not necessarily the highest, atmospheric SO4(2)- levels. Exposures of 100 to 900 micrograms/m3/hr were calculated for the acid events that were monitored. In contrast, earlier London studies indicated that apparent acidity in excess of 100 micrograms/m3 (as H2SO4) was present in the atmosphere, and exposures less than 2000 micrograms/m3/hr were possible. Our present knowledge about the frequency, magnitude, and duration of acidic sulfate aerosol events and episodes is insufficient. Efforts must be made to gather more data, but these should be done in such a way that evaluation of human exposure is the focus of the research. In addition, further data are required on the mechanisms of formation of H2SO4 and on what factors can be used to predict acidic sulfate episodes. PMID:2651103

  19. Characterization of aerosol transport in a recoil transfer chamber for heavy element chemistry

    NASA Astrophysics Data System (ADS)

    Lopez Morales, Gabriel; Tereshatov, Evgeny; Folden, Charles

    2014-09-01

    Heavy elements (HE) are elements with Z >103 that can be synthesized via target material bombardment by accelerated charged particles. Production and investigation of properties of new elements result in understanding of upper limit of Periodic Table of Elements. Study of chemical behavior of HE is usually based on comparison with their light homologue properties. Such experiments require transportation of elements of interest from a target chamber to a radiochemical laboratory within several seconds. Aerosol transport is a widely known way to transfer non-volatile elements in on-line experiments. This particular project is devoted to design, characterization and optimization of aerosol transport for implementation in future experiments at Cyclotron Institute, Texas A&M University. Different types of aerosol generators and particle parameters such as: size distribution, concentration and charge have been considered. Results showing procedure development will be presented. *Funded by DOE and NSF-REU Program.

  20. Characterizing Aerosolized Particulate As Part Of A Nanoprocess Exposure Assessment

    SciTech Connect

    Jankovic, John Timothy; Ogle, Burton R; Zontek, Tracy L; Hollenbeck, Scott M

    2010-01-01

    The purpose of this effort was to propose important aerosol characterization parameters that should be gathered as part of a nanomaterial hazard assessment and to offer a methodology for applying that data to daily operations. This study documents different ways of characterizing nanoscale materials using an aerosol from a process simulation consisting of a vacuum cleaner motor operating inside an enclosure. The aerosol is composed of insoluble carbon particles plus environmental background constituents. The average air concentration is 2.76E+5 p/cm3. Size measurements of the aerosol indicate > 70% of the particulate is blade-like in shape, 50% of which have a height dimension 100 nm. In terms of an equivalent spherical diameter 0.8% of the particulate is 100 nm in size. The carbon blades are characterized as having a root-mean-square roughness of 75 nm, and average fractal dimension of 2.25. These measures: aerosol chemistry, solubility, shape and size, surface area, number concentration and size distribution are important parameters to collect for current exposure assessment and toxicology and epidemiology studies.

  1. Chemical Characterization of Secondary Organic Aerosol from Oxidation of Isoprene Hydroxyhydroperoxides.

    PubMed

    Riva, Matthieu; Budisulistiorini, Sri H; Chen, Yuzhi; Zhang, Zhenfa; D'Ambro, Emma L; Zhang, Xuan; Gold, Avram; Turpin, Barbara J; Thornton, Joel A; Canagaratna, Manjula R; Surratt, Jason D

    2016-09-20

    Atmospheric oxidation of isoprene under low-NOx conditions leads to the formation of isoprene hydroxyhydroperoxides (ISOPOOH). Subsequent oxidation of ISOPOOH largely produces isoprene epoxydiols (IEPOX), which are known secondary organic aerosol (SOA) precursors. Although SOA from IEPOX has been previously examined, systematic studies of SOA characterization through a non-IEPOX route from 1,2-ISOPOOH oxidation are lacking. In the present work, SOA formation from the oxidation of authentic 1,2-ISOPOOH under low-NOx conditions was systematically examined with varying aerosol compositions and relative humidity. High yields of highly oxidized compounds, including multifunctional organosulfates (OSs) and hydroperoxides, were chemically characterized in both laboratory-generated SOA and fine aerosol samples collected from the southeastern U.S. IEPOX-derived SOA constituents were observed in all experiments, but their concentrations were only enhanced in the presence of acidified sulfate aerosol, consistent with prior work. High-resolution aerosol mass spectrometry (HR-AMS) reveals that 1,2-ISOPOOH-derived SOA formed through non-IEPOX routes exhibits a notable mass spectrum with a characteristic fragment ion at m/z 91. This laboratory-generated mass spectrum is strongly correlated with a factor recently resolved by positive matrix factorization (PMF) of aerosol mass spectrometer data collected in areas dominated by isoprene emissions, suggesting that the non-IEPOX pathway could contribute to ambient SOA measured in the Southeastern United States. PMID:27466979

  2. Multi-wavelength characterization of carbonaceous aerosol

    NASA Astrophysics Data System (ADS)

    Massabò, Dario; Caponi, Lorenzo; Chiara Bove, Maria; Piazzalunga, Andrea; Valli, Gianluigi; Vecchi, Roberta; Prati, Paolo

    2014-05-01

    Carbonaceous aerosol is a major component of the urban PM. It mainly consists of organic carbon (OC) and elemental carbon (EC) although a minor fraction of carbonate carbon could be also present. Elemental carbon is mainly found in the finer PM fractions (PM2.5 and PM1) and it is strongly light absorbing. When determined by optical methods, it is usually called black carbon (BC). The two quantities, EC and BC, even if both related to the refractory components of carbonaceous aerosols, do not exactly define the same PM component (Bond and Bergstrom, 2006; and references therein). Moreover, another fraction of light-absorbing carbon exists which is not black and it is generally called brown carbon (Andreae and Gelencsér, 2006). We introduce a simple, fully automatic, multi-wavelength and non-destructive optical system, actually a Multi-Wavelength Absorbance Analyzer, MWAA, to measure off-line the light absorption in Particulate Matter (PM) collected on filters and hence to derive the black and brown carbon content in the PM This gives the opportunity to measure in the same sample the concentration of total PM by gravimetric analysis, black and brown carbon, metals by, for instance, X Ray Fluorescence, and finally ions by Ion Chromatography. Up to 16 samples can be analyzed in sequence and in an automatic and controlled way within a few hours. The filter absorbance measured by MWAA was successfully validated both against a MAAP, Multi Angle Absorption Photometer (Petzold and Schönlinner, 2004), and the polar photometer of the University of Milan. The measurement of sample absorbance at three wavelengths gives the possibility to apportion different sources of carbonaceous PM, for instance fossil fuels and wood combustion. This can be done following the so called "aethalometer method" (Sandradewi et al., 2008;) but with some significant upgrades that will be discussed together the results of field campaigns in rural and urban sites. Andreae, M.O, and Gelencsér, A

  3. Characterization of selenium in ambient aerosols and primary emission sources.

    PubMed

    De Santiago, Arlette; Longo, Amelia F; Ingall, Ellery D; Diaz, Julia M; King, Laura E; Lai, Barry; Weber, Rodney J; Russell, Armistead G; Oakes, Michelle

    2014-08-19

    Atmospheric selenium (Se) in aerosols was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the oxidation state and elemental associations of Se in common primary emission sources and ambient aerosols collected from the greater Atlanta area. In the majority of ambient aerosol and primary emission source samples, the spectroscopic patterns as well as the absence of elemental correlations suggest Se is in an elemental, organic, or oxide form. XRF microscopy revealed numerous Se-rich particles, or hotspots, accounting on average for ∼16% of the total Se in ambient aerosols. Hotspots contained primarily Se(0)/Se(-II). However, larger, bulk spectroscopic characterizations revealed Se(IV) as the dominant oxidation state in ambient aerosol, followed by Se(0)/Se(-II) and Se(VI). Se(IV) was the only observed oxidation state in gasoline, diesel, and coal fly ash, while biomass burning contained a combination of Se(0)/Se(-II) and Se(IV). Although the majority of Se in aerosols was in the most toxic form, the Se concentration is well below the California Environmental Protection Agency chronic exposure limit (∼20000 ng/m(3)). PMID:25075640

  4. Generation and Characterization of Indoor Fungal Aerosols for Inhalation Studies

    PubMed Central

    Larsen, Søren T.; Koponen, Ismo K.; Kling, Kirsten I.; Barooni, Afnan; Karottki, Dorina Gabriela; Tendal, Kira; Wolkoff, Peder

    2016-01-01

    In the indoor environment, people are exposed to several fungal species. Evident dampness is associated with increased respiratory symptoms. To examine the immune responses associated with fungal exposure, mice are often exposed to a single species grown on an agar medium. The aim of this study was to develop an inhalation exposure system to be able to examine responses in mice exposed to mixed fungal species aerosolized from fungus-infested building materials. Indoor airborne fungi were sampled and cultivated on gypsum boards. Aerosols were characterized and compared with aerosols in homes. Aerosols containing 107 CFU of fungi/m3 air were generated repeatedly from fungus-infested gypsum boards in a mouse exposure chamber. Aerosols contained Aspergillus nidulans, Aspergillus niger, Aspergillus ustus, Aspergillus versicolor, Chaetomium globosum, Cladosporium herbarum, Penicillium brevicompactum, Penicillium camemberti, Penicillium chrysogenum, Penicillium commune, Penicillium glabrum, Penicillium olsonii, Penicillium rugulosum, Stachybotrys chartarum, and Wallemia sebi. They were all among the most abundant airborne species identified in 28 homes. Nine species from gypsum boards and 11 species in the homes are associated with water damage. Most fungi were present as single spores, but chains and clusters of different species and fragments were also present. The variation in exposure level during the 60 min of aerosol generation was similar to the variation measured in homes. Through aerosolization of fungi from the indoor environment, cultured on gypsum boards, it was possible to generate realistic aerosols in terms of species composition, concentration, and particle sizes. The inhalation-exposure system can be used to study responses to indoor fungi associated with water damage and the importance of fungal species composition. PMID:26921421

  5. The Pasadena Aerosol Characterization Observatory (PACO): chemical and physical analysis of the Western Los Angeles Basin aerosol

    NASA Astrophysics Data System (ADS)

    Hersey, S. P.; Craven, J. S.; Schilling, K. A.; Metcalf, A. R.; Sorooshian, A.; Chan, M. N.; Flagan, R. C.; Seinfeld, J. H.

    2011-02-01

    The Pasadena Aerosol Characterization Observatory (PACO) represents the first major aerosol characterization experiment centered in the Western/Central Los Angeles Basin. The sampling site, located on the campus of the California Institute of Technology in Pasadena, was positioned to sample a continuous afternoon influx of transported urban aerosol with a photochemical age of 1-2 h and generally free from major local contributions. Sampling spanned 5 months during the summer of 2009, which were broken into 3 regimes on the basis of distinct meteorological conditions. Regime I was characterized by a series of low pressure systems, resulting in high humidity and rainy periods with clean conditions. Regime II typified early summer meteorology, with significant morning marine layers and warm, sunny afternoons. Regime III was characterized by hot, dry conditions with little marine layer influence. Organic aerosol (OA) is the most significant constituent of Los Angeles aerosol (42, 43, and 55% of total submicron mass in regimes I, II, and III, respectively), and that the overall oxidation state remains relatively constant on timescales of days to weeks (O:C = 0.44 ± 0.08, 0.55 ± 0.05, and 0.48 ± 0.08 during regimes I, II, and III, respectively), with no difference in O:C between morning and afternoon periods. Periods characterized by significant morning marine layer influence followed by photochemically favorable afternoons displayed significantly higher aerosol mass and O:C ratio, suggesting that aqueous processes may be important in the generation of secondary aerosol and oxidized organic aerosol (OOA) in Los Angeles. Water soluble organic mass (WSOM) reaches maxima near 14:00-15:00 local time (LT), but the percentage of AMS organic mass contributed by WSOM remains relatively constant throughout the day. Sulfate and nitrate reside predominantly in accumulation mode aerosol, while afternoon SOA production coincides with the appearance of a distinct fine mode

  6. Comprehensive characterization of PM2.5 aerosols in Singapore

    NASA Astrophysics Data System (ADS)

    Balasubramanian, R.; Qian, W.-B.; Decesari, S.; Facchini, M. C.; Fuzzi, S.

    2003-08-01

    A comprehensive characterization of PM2.5 aerosols collected in Singapore from January through December 2000 is presented. The annual average mass concentration of PM2.5 was 27.2 μg/m3. The atmospheric loading of PM2.5 was elevated sporadically from March through May, mainly due to advection of biomass burning (deliberate fires to clear plantation areas) impacted air masses from Sumatra, Indonesia. Satellite images of the area, trajectory calculations, and surface wind direction data are in support of the transport of pyrogenic products from Sumatra toward Singapore. Aerosol samples collected during the dry season were analyzed for water-soluble ions, water-soluble organic compounds (WSOC), elemental carbon (EC), organic carbon, and trace elements using a number of analytical techniques. The major components were sulfate, EC, water-soluble carbonaceous materials, and water-insoluble carbonaceous materials. Aerosol WSOC were characterized based on a combination of chromatographic separations by ion exchange chromatography, functional group investigation by proton nuclear magnetic resonance, and total organic carbon determination. The comprehensive chemical characterization of PM2.5 particles revealed that both non-sea-salt sufate (nss-SO42-) and carbonaceous aerosols mainly contributed to the increase in the mass concentration of aerosols during the smoke haze period. Using a mass closure test (a mass balance), we determined whether the physical measurement of gravimetric fine PM concentration of a sample is equal to the summed concentrations of the individually identified chemical constituents (measured or inferred) in the sample. The sum of the determined groups of aerosol components and the gravimetrically determined mass agreed reasonably well. Principal component analysis was performed from the combined data set, and five factors were observed: a soil dust component, a metallurgical industry factor, a factor representing emissions from biomass burning and

  7. Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments.

    PubMed

    Gopalakrishnan, V; Subramanian, V; Baskaran, R; Venkatraman, B

    2015-07-01

    Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging. PMID:26233420

  8. Acidic sulfate aerosols: characterization and exposure

    SciTech Connect

    Lioy, P.J.; Waldman, J.M.

    1989-02-01

    Exposures to acidic aerosol in the atmosphere are calculated from data reported in the scientific literature. The majority of date was not derived from studies necessarily designed to examine human exposures. Most of the studies were designed to investigate the characteristics of the atmosphere. However, the measurements were useful in defining two potential exposure situations: regional stagnation and transport conditions and local plume impacts. Levels of acidicaerosol in excess of 20 to 40 micrograms/m/sup 3/ (as H/sub 2/SO/sub 4/) have been observed for time durations ranging from 1 to 12 hr. These were associated with high, but not necessarily the highest, atmospheric SO/sub 4/(2)- levels. Exposures of 100 to 900 micrograms/m/sup 3//hr were calculated for the acid events that were monitored. In contrast, earlier London studies indicated that apparent acidity in excess of 100 micrograms/m/sup 3/ (as H/sub 2/SO/sub 4/) was present in the atmosphere, and exposures less than 2000 micrograms/m/sup 3//hr were possible. Our present knowledge about the frequency, magnitude, and duration of acidic sulfate aerosol events and episodes is insufficient. Efforts must be made to gather more data, but these should be done in such a way that evaluation of human exposure is the focus of the research. In addition, further data are required on the mechanisms of formation of H/sub 2/SO/sub 4/ and on what factors can be used to predict acidic sulfate episodes. 96 references.

  9. The Indian ocean experiment: aerosol forcing obtained from satellite data

    NASA Astrophysics Data System (ADS)

    Rajeev, K.; Ramanathan, V.

    The tropical Indian Ocean provides an ideal and unique natural laboratory to observe and understand the role of anthropogenic aerosols in climate forcing. Since 1996, an international team of American, European and Indian scientists have been collecting aerosol, chemical and radiation data from ships and surface stations, which culminated in a multi-platform field experiment conducted during January to March of 1999. A persistent haze layer that spread over most of the northern Indian Ocean during wintertime was discovered. The layer, a complex mix of organics, black carbon, sulfates, nitrates and other species, subjects the lower atmosphere to a strong radiative heating and a larger reduction in the solar heating of the ocean. We present here the regional distribution of aerosols and the resulting clear sky aerosol radiative forcing at top-of-atmosphere (TOA) observed over the Indian Ocean during the winter months of 1997, 1998 and 1999 based on the aerosol optical depth (AOD) estimated using NOAA14-AVHRR and the TOA radiation budget data from CERES on board TRMM. Using the ratio of surface to TOA clear sky aerosol radiative forcing observed during the same period over the Indian Ocean island of Kaashidhoo (Satheesh and Ramanathan, 2000), the clear sky aerosol radiative forcing at the surface and the atmosphere are discussed. The regional maps of AVHRR derived AOD show abnormally large aerosol concentration during the winter of 1999 which is about 1.5 to 2 times larger than the AOD during the corresponding period of 1997 and 1998. A large latitudinal gradient in AOD is observed during all the three years of observation, with maximum AOD in the northern hemisphere. The diurnal mean clear sky aerosol forcing at TOA in the northern hemisphere Indian Ocean is in the range of -4 to -16 Wm -2 and had large spatio-temporal variations while in the southern hemisphere Indian Ocean it is in the range of 0 to -6Wm -2. The importance of integrating in-situ data with satellite

  10. Characterization of aerosols from eruptions of Mount St. Helens

    SciTech Connect

    Chuan, R.L.; Woods, D.C.; McCormick, M.P.

    1981-01-01

    Measurements of mass concentration and size distribution of aerosols from eruptions of Mount St. Helens as well as morphological and elemental analyses were obtained between 7 April and 7 August 1980. In situ measurements were made in early phreatic and later, minor phreatomagmatic eruption clouds near the vent of the volcano and in plumes injected into the stratosphere from the major eruptions of 18 and 25 May. The phreatic aerosol was characterized by an essentially monomodal size distribution dominated by silicate particles larger than 10 micrometers in diameter. The phreatomagmatic eruption cloud was multimodal; the large size mode consisted of silicate particles and the small size modes were made up of mixtures of sulfuric acid and silicate particles. The stratospheric aerosol from the main eruption exhibited a characteristic narrow single mode with particles less than 1 micrometer in diameter and nearly all of the mass made up of sulfuric acid droplets.

  11. Characterization of aerosols from eruptions of mount st. Helens.

    PubMed

    Chuan, R L; Woods, D C; McCormick, M P

    1981-02-20

    Measurements of mass concentration and size distribution of aerosols from eruptions of Mount St. Helens as well as morphological and elemental analyses were obtained between 7 April and 7 August 1980. In situ measurements were made in early phreatic and later, minor phreatomagmatic eruption clouds near the vent of the volcano and in plumes injected into the stratosphere from the major eruptions of 18 and 25 May. The phreatic aerosol was characterized by an essentially monomodal size distribution dominated by silicate particles larger than 10 micrometers in diameter. The phreatomagmatic eruption cloud was multimodal; the large size mode consisted of silicate particles and the small size modes were made up of mixtures of sulfuric acid and silicate particles. The stratospheric aerosol from the main eruption exhibited a characteristic narrow single mode with particles less than 1 micrometer in diameter and nearly all of the mass made up of sulfuric acid droplets.

  12. Characterization and reconstruction of historical London, England, acidic aerosol concentrations

    SciTech Connect

    Ito, K.; Thurston, G.D.

    1989-02-01

    Several past studies of the historical London air pollution record have reported an association between daily mortality and British Smoke levels. However, this pollution index does not give direct information on particulate mass or its chemical composition. A more specific particulate matter index, aerosol acidity, was measured at a site in central London, and daily data are available for the period 1963-1972. British smoke and SO/sub 2/ were also measured at the same site. Also, meteorological parameters were routinely measured at a nearby British Meteorological Office. Thus, daily fluctuation of the acidic aerosols was characterized in terms of other environmental parameters. Each of the other parameters analyzed seems necessary, but not sufficient to explain a high level of acidic aerosol. Overall, about half of the variance of log-transformed daily fluctuations of acidic aerosols can be explained by a combination of parameters including SO/sub 2/ and British smoke concentrations, temperature, ventilation by wind, and humidity. The rest of the variance cannot be explained by the parameters included in this analysis. Potential factors responsible for this unique variance would be variations in the availability of basic gases to cause neutralization and variation in the availability of catalytic metal salts. Because the acidic aerosol has a unique component of variation, it may be possible to distinguish health effects due to this specific pollutant from other available pollution indices or environmental factors.

  13. Characterization and reconstruction of historical London, England, acidic aerosol concentrations.

    PubMed

    Ito, K; Thurston, G D

    1989-02-01

    Several past studies of the historical London air pollution record have reported an association between daily mortality and British Smoke levels. However, this pollution index does not give direct information on particulate mass or its chemical composition. A more specific particulate matter index, aerosol acidity, was measured at a site in central London, and daily data are available for the period 1963-1972. British Smoke and SO2 were also measured at the same site. Also, meteorological parameters were routinely measured at a nearby British Meteorological Office. Thus, daily fluctuation of the acidic aerosols was characterized in terms of other environmental parameters. Each of the other parameters analyzed seems necessary, but not sufficient to explain a high level of acidic aerosol. Overall, about half of the variance of log-transformed daily fluctuations of acidic aerosols can be explained by a combination of parameters including SO2 and British Smoke concentrations, temperature, ventilation by wind, and humidity. The rest of the variance cannot be explained by the parameters included in this analysis. Potential factors responsible for this unique variance would be variations in the availability of basic gases to cause neutralization and variation in the availability of catalytic metal salts. Because the acidic aerosol has a unique component of variation, it may be possible to distinguish health effects due to this specific pollutant from other available pollution indices or environmental factors.

  14. Aerosol Properties over the Indo-Gangetic Plain: A Mesoscale Perspective from the TIGERZ Experiment

    NASA Technical Reports Server (NTRS)

    Giles, David M.; Holben, Brent N.; Tripathi, Sachchida; Eck, Thomas F.; Newcomb, W. Wayne; Slutsker, Ilya; Dickerson, Russell R.; Thompson, Anne M.; Mattoo, Shana; Wang, Sheng-Hsiang; Singh, Remesh P.; Sinyuk, Aliaksandr; Schafer, Joel S.

    2011-01-01

    High aerosol loading over the northern Indian subcontinent can result in poor air quality leading to human health consequences and climate perturbations. The international 2008 TIGERZ experiment intensive operational period (IOP) was conducted in the Indo \\Gangetic Plain (IGP) around the industrial city of Kanpur (26.51degN, 80.23deg E), India, during the premonsoon (April-June). Aerosol Robotic Network (AERONET) Sun photometers performed frequent measurements of aerosol properties at temporary sites distributed within an area covering 50 sq km around Kanpur to characterize pollution and dust in a region where complex aerosol mixtures and semi \\bright surface effects complicate satellite retrieval algorithms. TIGERZ IOP Sun photometers quantified aerosol optical depth (AOD) increases up to 0.10 within and downwind of the city, with urban emissions accounting for 10 C20% of the IGP aerosol loading on deployment days. TIGERZ IOP area \\averaged volume size distribution and single scattering albedo retrievals indicated spatially homogeneous, uniformly sized, spectrally absorbing pollution and dust particles. Aerosol absorption and size relationships were used to categorize black carbon and dust as dominant absorbers and to identify a third category in which both black carbon and dust dominate absorption.Moderate Resolution Imaging Spectroradiometer (MODIS) AOD retrievals with the lowest quality assurance (QA > or = 0) flags were biased high with respect to TIGERZ IOP area \\averaged measurements. MODIS AOD retrievals with QA 0 had moderate correlation (R(sup 2) = 0.52-69) with the Kanpur AERONET site, whereas retrievals with QA > 0 were limited in number. Mesoscale \\distributed Sun photometers quantified temporal and spatial variability of aerosol properties, and these results were used to validate satellite retrievals.

  15. Aerosol properties over the Indo-Gangetic Plain: A mesoscale perspective from the TIGERZ experiment

    NASA Astrophysics Data System (ADS)

    Giles, David M.; Holben, Brent N.; Tripathi, Sachchida N.; Eck, Thomas F.; Newcomb, W. Wayne; Slutsker, Ilya; Dickerson, Russell R.; Thompson, Anne M.; Mattoo, Shana; Wang, Sheng-Hsiang; Singh, Remesh P.; Sinyuk, Aliaksandr; Schafer, Joel S.

    2011-09-01

    High aerosol loading over the northern Indian subcontinent can result in poor air quality leading to human health consequences and climate perturbations. The international 2008 TIGERZ experiment intensive operational period (IOP) was conducted in the Indo-Gangetic Plain (IGP) around the industrial city of Kanpur (26.51°N, 80.23°E), India, during the premonsoon (April-June). Aerosol Robotic Network (AERONET) Sun photometers performed frequent measurements of aerosol properties at temporary sites distributed within an area covering ˜50 km2 around Kanpur to characterize pollution and dust in a region where complex aerosol mixtures and semi-bright surface effects complicate satellite retrieval algorithms. TIGERZ IOP Sun photometers quantified aerosol optical depth (AOD) increases up to ˜0.10 within and downwind of the city, with urban emissions accounting for ˜10-20% of the IGP aerosol loading on deployment days. TIGERZ IOP area-averaged volume size distribution and single scattering albedo retrievals indicated spatially homogeneous, uniformly sized, spectrally absorbing pollution and dust particles. Aerosol absorption and size relationships were used to categorize black carbon and dust as dominant absorbers and to identify a third category in which both black carbon and dust dominate absorption. Moderate Resolution Imaging Spectroradiometer (MODIS) AOD retrievals with the lowest quality assurance (QA ≥ 0) flags were biased high with respect to TIGERZ IOP area-averaged measurements. MODIS AOD retrievals with QA ≥ 0 had moderate correlation (R2 = 0.52-0.69) with the Kanpur AERONET site, whereas retrievals with QA > 0 were limited in number. Mesoscale-distributed Sun photometers quantified temporal and spatial variability of aerosol properties, and these results were used to validate satellite retrievals.

  16. Continuation of Lithium Aerosol Injection Experiments on NSTX

    NASA Astrophysics Data System (ADS)

    Mansfield, D. K.; Roquemore, A. L.; Kugel, H.; Maingi, R.; Irby, J.; Wang, Z.

    2009-11-01

    During the 2008 run campaign, a Li powder dropper was installed on NSTX that successfully injected up to 35 mg/s of Li aerosol into the SOL. Initial improvements in the plasma performance from these initial experiments warranted the installation of a second Li dropper for the 2009 campaign. Design improvements in the dropper have resulted in accurate control of the flux of Li powder injected. The improved duel-dropper system has injected lithium fluxes of from 30 - 140 mg/s. At the highest flux, plasmas of 950 kA with 6 MW off NBI auxiliary heating have been successfully operated. This flux corresponds to 2.5 x106 - 5.8 x106 aerosol particles/s and is stoichiometrically equivalent 80 - 187 Torr L/s of D2. Operation of the Li dropper and the effects of the Li aerosol on the plasma performance will be discussed.

  17. Complex Aerosol Experiment in Western Siberia (April - October 2013)

    NASA Astrophysics Data System (ADS)

    Matvienko, G. G.; Belan, B. D.; Panchenko, M. V.; Romanovskii, O. A.; Sakerin, S. M.; Kabanov, D. M.; Turchinovich, S. A.; Turchinovich, Yu. S.; Eremina, T. A.; Kozlov, V. S.; Terpugova, S. A.; Pol'kin, V. V.; Yausheva, E. P.; Chernov, D. G.; Zuravleva, T. B.; Bedareva, T. V.; Odintsov, S. L.; Burlakov, V. D.; Arshinov, M. Yu.; Ivlev, G. A.; Savkin, D. E.; Fofonov, A. V.; Gladkikh, V. A.; Kamardin, A. P.; Balin, Yu. S.; Kokhanenko, G. P.; Penner, I. E.; Samoilova, S. V.; Antokhin, P. N.; Arshinova, V. G.; Davydov, D. K.; Kozlov, A. V.; Pestunov, D. A.; Rasskazchikova, T. M.; Simonenkov, D. V.; Sklyadneva, T. K.; Tolmachev, G. N.; Belan, S. B.; Shmargunov, V. P.

    2016-06-01

    The primary project objective was to accomplish the Complex Aerosol Experiment, during which the aerosol properties should be measured in the near-ground layer and free atmosphere. Three measurement cycles were performed during the project implementation: in spring period (April), when the maximum of aerosol generation is observed; in summer (July), when atmospheric boundary layer height and mixing layer height are maximal; and in late summer - early autumn (October), when the secondary particle nucleation period is recorded. Numerical calculations were compared with measurements of fluxes of downward solar radiation. It was shown that the relative differences between model and experimental values of fluxes of direct and total radiation, on the average, do not exceed 1% and 3% respectively.

  18. Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Daellenbach, K. R.; Bozzetti, C.; Křepelová, A.; Canonaco, F.; Wolf, R.; Zotter, P.; Fermo, P.; Crippa, M.; Slowik, J. G.; Sosedova, Y.; Zhang, Y.; Huang, R.-J.; Poulain, L.; Szidat, S.; Baltensperger, U.; Prévôt, A. S. H.; El Haddad, I.

    2015-08-01

    Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS) have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make impractical its deployment at sufficient sites to determine regional characteristics. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM) filter samples (PM1, PM2.5, PM10) collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g. AMS or Aerosol Chemical Speciation Monitor (ACSM). The bulk recoveries of organic aerosol (60-91 %) achieved using this technique, together with low detection limits (0.8 μg of organic aerosol on the analyzed filter fraction) allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon, oxygen containing and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g. filter artifacts and limited time resolution) may be used to enhance the AMS capabilities in measuring size-fractionated, spatially-resolved long-term datasets.

  19. Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Daellenbach, K. R.; Bozzetti, C.; Křepelová, A.; Canonaco, F.; Wolf, R.; Zotter, P.; Fermo, P.; Crippa, M.; Slowik, J. G.; Sosedova, Y.; Zhang, Y.; Huang, R.-J.; Poulain, L.; Szidat, S.; Baltensperger, U.; El Haddad, I.; Prévôt, A. S. H.

    2016-01-01

    Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS) have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make its deployment at sufficient sites to determine regional characteristics impractical. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM) filter samples (PM1, PM2.5, and PM10, i.e., PM with aerodynamic diameters smaller than 1, 2.5, and 10 µm, respectively), collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g., AMS or Aerosol Chemical Speciation Monitor (ACSM). The bulk recoveries of organic aerosol (60-91 %) achieved using this technique, together with low detection limits (0.8 µg of organic aerosol on the analyzed filter fraction) allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon ions, ions containing oxygen, and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning, and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g., filter artifacts and limited time resolution) may be used to enhance the AMS capabilities in measuring size-fractionated, spatially resolved long-term data sets.

  20. Aerosol characterization at the Saharan AERONET site Tamanrasset

    NASA Astrophysics Data System (ADS)

    Guirado, C.; Cuevas, E.; Cachorro, V. E.; Toledano, C.; Alonso-Pérez, S.; Bustos, J. J.; Basart, S.; Romero, P. M.; Camino, C.; Mimouni, M.; Zeudmi, L.; Goloub, P.; Baldasano, J. M.; de Frutos, A. M.

    2014-06-01

    More than two years of columnar atmospheric aerosol measurements (2006-2009) at Tamanrasset site, in the heart of the Sahara desert, are analysed. AERONET level 2.0 data were used. The KCICLO method was applied to a part of level 1.5 data series to improve the quality of the results. The annual variability of aerosol optical depth (AOD) and Angstrom exponent (AE) has been found to be strongly linked to the Convective Boundary Layer (CBL) thermodynamic features. The dry-cool season (autumn and winter time) is characterized by a shallow CBL and very low mean turbidity (AOD ~ 0.09 at 440 nm, AE ~ 0.62). The wet-hot season (spring and summer time) is dominated by high turbidity of coarse dust particles (AE ~ 0.28, AOD ~ 0.39 at 440 nm) and a deep CBL. The aerosol-type characterization shows desert mineral dust as prevailing aerosol. Both pure Saharan dust and very clear sky conditions are observed depending on the season. However, several case studies indicate an anthropogenic fine mode contribution from Libya and Algeria's industrial areas. The Concentration Weighted Trajectory (CWT) source apportionment method was used to identify potential sources of air masses arriving at Tamanrasset at several heights for each season. Microphysical and optical properties and precipitable water vapour were also investigated.

  1. Multi-walled carbon nanotubes: sampling criteria and aerosol characterization

    PubMed Central

    Chen, Bean T.; Schwegler-Berry, Diane; McKinney, Walter; Stone, Samuel; Cumpston, Jared L.; Friend, Sherri; Porter, Dale W.; Castranova, Vincent; Frazer, David G.

    2015-01-01

    This study intends to develop protocols for sampling and characterizing multi-walled carbon nanotube (MWCNT) aerosols in workplaces or during inhalation studies. Manufactured dry powder containing MWCNT’s, combined with soot and metal catalysts, form complex morphologies and diverse shapes. The aerosols, examined in this study, were produced using an acoustical generator. Representative samples were collected from an exposure chamber using filters and a cascade impactor for microscopic and gravimetric analyses. Results from filters showed that a density of 0.008–0.10 particles per µm2 filter surface provided adequate samples for particle counting and sizing. Microscopic counting indicated that MWCNT’s, resuspended at a concentration of 10 mg/m3, contained 2.7 × 104 particles/cm3. Each particle structure contained an average of 18 nanotubes, resulting in a total of 4.9 × 105 nanotubes/cm3. In addition, fibrous particles within the aerosol had a count median length of 3.04 µm and a width of 100.3 nm, while the isometric particles had a count median diameter of 0.90 µm. A combination of impactor and microscopic measurements established that the mass median aerodynamic diameter of the mixture was 1.5 µm. It was also determined that the mean effective density of well-defined isometric particles was between 0.71 and 0.88 g/cm3, and the mean shape factor of individual nanotubes was between 1.94 and 2.71. The information obtained from this study can be used for designing animal inhalation exposure studies and adopted as guidance for sampling and characterizing MWCNT aerosols in workplaces. The measurement scheme should be relevant for any carbon nanotube aerosol. PMID:23033994

  2. Aerosol characterization at the Saharan AERONET site Tamanrasset

    NASA Astrophysics Data System (ADS)

    Guirado, C.; Cuevas, E.; Cachorro, V. E.; Toledano, C.; Alonso-Pérez, S.; Bustos, J. J.; Basart, S.; Romero, P. M.; Camino, C.; Mimouni, M.; Zeudmi, L.; Goloub, P.; Baldasano, J. M.; de Frutos, A. M.

    2014-11-01

    More than 2 years of columnar atmospheric aerosol measurements (2006-2009) at the Tamanrasset site (22.79° N, 5.53° E, 1377 m a.s.l.), in the heart of the Sahara, are analysed. Aerosol Robotic Network (AERONET) level 2.0 data were used. The KCICLO (K is the name of a constant and ciclo means cycle in Spanish) method was applied to a part of the level 1.5 data series to improve the quality of the results. The annual variability of aerosol optical depth (AOD) and Ångström exponent (AE) has been found to be strongly linked to the convective boundary layer (CBL) thermodynamic features. The dry-cool season (autumn and winter) is characterized by a shallow CBL and very low mean turbidity (AOD ~ 0.09 at 440 nm, AE ~ 0.62). The wet-hot season (spring and summer) is dominated by high turbidity of coarse dust particles (AE ~ 0.28, AOD ~ 0.39 at 440 nm) and a deep CBL. The aerosol-type characterization shows desert mineral dust as the prevailing aerosol. Both pure Saharan dust and very clear sky conditions are observed depending on the season. However, several case studies indicate an anthropogenic fine mode contribution from the industrial areas in Libya and Algeria. The concentration weighted trajectory (CWT) source apportionment method was used to identify potential sources of air masses arriving at Tamanrasset at several heights for each season. Microphysical and optical properties and precipitable water vapour were also investigated.

  3. Satellite perspective of aerosol intercontinental transport: From qualitative tracking to quantitative characterization

    NASA Astrophysics Data System (ADS)

    Yu, Hongbin; Remer, Lorraine A.; Kahn, Ralph A.; Chin, Mian; Zhang, Yan

    2013-04-01

    Evidence of aerosol intercontinental transport (ICT) is both widespread and compelling. Model simulations suggest that ICT could significantly affect regional air quality and climate, but the broad inter-model spread of results underscores a need of constraining model simulations with measurements. Satellites have inherent advantages over in situ measurements to characterize aerosol ICT, because of their spatial and temporal coverage. Significant progress in satellite remote sensing of aerosol properties during the Earth Observing System (EOS) era offers the opportunity to increase quantitative characterization and estimates of aerosol ICT beyond the capability of pre-EOS era satellites that could only qualitatively track aerosol plumes. EOS satellites also observe emission strengths and injection heights of some aerosols, aerosol precursors, and aerosol-related gases, which can help characterize aerosol ICT. We review how the current generation of satellite measurements have been used to (1) characterize the evolution of aerosol plumes (e.g., both horizontal and vertical transport, and properties) on an episodic basis, (2) understand the seasonal and inter-annual variations of aerosol ICT and their control factors, (3) estimate the export and import fluxes of aerosols, and (4) evaluate and constrain model simulations. Substantial effort is needed to further explore an integrated approach using measurements from on-orbit satellites (e.g., A-Train synergy) for observational characterization and model constraint of aerosol intercontinental transport and to develop advanced sensors for future missions.

  4. Satellite Perspective of Aerosol Intercontinental Transport: From Qualitative Tracking to Quantitative Characterization

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Remer, Lorraine A.; Kahn, Ralph A.; Chin, Mian; Zhang, Yan

    2012-01-01

    Evidence of aerosol intercontinental transport (ICT) is both widespread and compelling. Model simulations suggest that ICT could significantly affect regional air quality and climate, but the broad inter-model spread of results underscores a need of constraining model simulations with measurements. Satellites have inherent advantages over in situ measurements to characterize aerosol ICT, because of their spatial and temporal coverage. Significant progress in satellite remote sensing of aerosol properties during the Earth Observing System (EOS) era offers opportunity to increase quantitative characterization and estimates of aerosol ICT, beyond the capability of pre-EOS era satellites that could only qualitatively track aerosol plumes. EOS satellites also observe emission strengths and injection heights of some aerosols, aerosol precursors, and aerosol-related gases, which can help characterize aerosol ICT. After an overview of these advances, we review how the current generation of satellite measurements have been used to (1) characterize the evolution of aerosol plumes (e.g., both horizontal and vertical transport, and properties) on an episodic basis, (2) understand the seasonal and inter-annual variations of aerosol ICT and their control factors, (3) estimate the export and import fluxes of aerosols, and (4) evaluate and constrain model simulations. Substantial effort is needed to further explore an integrated approach using measurements from on-orbit satellites (e.g., A-Train synergy) for observational characterization and model constraint of aerosol intercontinental transport and to develop advanced sensors for future missions.

  5. Characterization of aerosol composition and sources in the greater Atlanta area by aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Ng, N. L.; Xu, L.; Suresh, S.; Weber, R. J. J.; Baumann, K.; Edgerton, E. S.

    2014-12-01

    An important and uncertain aspect of biogenic secondary organic aerosol (SOA) formation is that it is often associated with anthropogenic pollution tracers. Prior studies in Atlanta suggested that 70-80% of the carbon in water-soluble organic carbon (WSOC) is modern, yet it is well-correlated with the anthropogenic CO. In this study, we deployed a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) at multiple sites in different seasons (May 2012-February 2013) to characterize the sources and chemical composition of aerosols in the greater Atlanta area. This area in the SE US is ideal to investigate anthropogenic-biogenic interactions due to high natural and anthropogenic emissions. These extensive field studies are part of the Southeastern Center for Air Pollution and Epidemiology study (SCAPE). The HR-ToF-AMS is deployed at four sites (~ 3 weeks each) in rotation: Jefferson Street (urban), Yorkville (rural), roadside site (near Highway 75/85), and Georgia Tech site (campus), with the urban and rural sites being part of the SEARCH network. We obtained seven HR-ToF-AMS datasets in total. During the entire measurement period, the ACSM is stationary at the GIT site and samples continuously. We perform positive matrix factorization (PMF) analysis on the HR-ToF-AMS and ACSM data to deconvolve the OA into different components. While the diurnal cycle of the total OA is flat as what have been previously observed, the OA factors resolved by PMF analysis show distinctively different diurnal trends. We find that the "more-oxidized oxygenated OA" (MO-OOA) constitutes a major fraction of OA at all sites. In summer, OA is dominated by SOA, e.g., isoprene-OA and OOA with different degrees of oxidation. In contrary, biomass burning OA is more prominent in winter data. By comparing HR-ToF-AMS and ACSM data during the same sampling periods, we find that the aerosol time series are highly correlated, indicating the

  6. The Pasadena Aerosol Characterization Observatory (PACO): chemical and physical analysis of the Western Los Angeles basin aerosol

    NASA Astrophysics Data System (ADS)

    Hersey, S. P.; Craven, J. S.; Schilling, K. A.; Metcalf, A. R.; Sorooshian, A.; Chan, M. N.; Flagan, R. C.; Seinfeld, J. H.

    2011-08-01

    The Pasadena Aerosol Characterization Observatory (PACO) represents the first major aerosol characterization experiment centered in the Western/Central Los Angeles Basin. The sampling site, located on the campus of the California Institute of Technology in Pasadena, was positioned to sample a continuous afternoon influx of transported urban aerosol with a photochemical age of 1-2 h and generally free from major local contributions. Sampling spanned 5 months during the summer of 2009, which were broken into 3 regimes on the basis of distinct meteorological conditions. Regime I was characterized by a series of low pressure systems, resulting in high humidity and rainy periods with clean conditions. Regime II typified early summer meteorology, with significant morning marine layers and warm, sunny afternoons. Regime III was characterized by hot, dry conditions with little marine layer influence. Regardless of regime, organic aerosol (OA) is the most significant constituent of nonrefractory submicron Los Angeles aerosol (42, 43, and 55 % of total submicron mass in regimes I, II, and III, respectively). The overall oxidation state remains relatively constant on timescales of days to weeks (O:C = 0.44 ± 0.08, 0.55 ± 0.05, and 0.48 ± 0.08 during regimes I, II, and III, respectively), with no difference in O:C between morning and afternoon periods. Periods characterized by significant morning marine layer influence followed by photochemically favorable afternoons displayed significantly higher aerosol mass and O:C ratio, suggesting that aqueous processes may be important in the generation of secondary aerosol and oxidized organic aerosol (OOA) in Los Angeles. Online analysis of water soluble organic carbon (WSOC) indicates that water soluble organic mass (WSOM) reaches maxima near 14:00-15:00 local time (LT), but the percentage of AMS organic mass contributed by WSOM remains relatively constant throughout the day. Sulfate and nitrate reside predominantly in accumulation

  7. Characterization of an aerosol chamber for human exposures to endotoxin.

    PubMed

    Taylor, L; Reist, P C; Boehlecke, B A; Jacobs, R R

    2000-03-01

    The objective of this study was to develop and characterize an exposure chamber in which human subjects could be exposed to low dust concentrations carrying an endotoxin coating. An exposure chamber, dust dispersion method, and endotoxin characterization technique were developed for inhalation exposures. A 6.27 m3 exposure chamber was designed and constructed from cinder block, glass windows, and Plexiglas. Using an acetone adhesion process, Enterobacter agglomerans were adsorbed onto respirable cellulose particles to create the endotoxin aerosol. The size distribution of the endotoxin-treated particles was verified using light microscopy and cascade impactors. A dry powder dust generator was refined to consistently disperse small quantities of the aerosol into the chamber to maintain dust concentrations at approximately 250 micrograms/m3. Dust levels during the chamber exposures were monitored using a portable continuous aerosol monitor (PCAM). During initial exposure runs, PCAM monitoring stations were positioned at different locations within a 0.5-meter matrix to document mixing patterns. Total dust and cascade impactor samples were collected throughout each exposure period to characterize the chamber operating system and insure the mean airborne dust concentration fulfilled target levels. A one-factor analysis of variance at the 95 percent confidence interval illustrated that there was not a statistically significant difference in the mean dust concentration throughout the exposure runs compared to the individual runs. Together the consistency of the total dust filters, endotoxin concentrations, and aerosol-monitoring instrument were adequate to allow use of the chamber for experimental studies involving human volunteers.

  8. Characterization of aerosols and fibers emitted from composite materials combustion.

    PubMed

    Chivas-Joly, C; Gaie-Levrel, F; Motzkus, C; Ducourtieux, S; Delvallée, A; De Lagos, F; Nevé, S Le; Gutierrez, J; Lopez-Cuesta, J-M

    2016-01-15

    This work investigates the aerosols emitted during combustion of aircraft and naval structural composite materials (epoxy resin/carbon fibers and vinyl ester/glass fibers and carbon nanotubes). Combustion tests were performed at lab-scale using a modified cone calorimeter. The aerosols emitted have been characterized using various metrological devices devoted to the analysis of aerosols. The influence of the nature of polymer matrices, the incorporation of fibers and carbon nanotubes as well as glass reinforcements on the number concentration and the size distribution of airborne particles produced, was studied in the 5 nm-10 μm range. Incorporation of carbon fibers into epoxy resin significantly reduced the total particle number concentration. In addition, the interlaced orientation of carbon fibers limited the particles production compared to the composites with unidirectional one. The carbon nanotubes loading in vinyl ester resin composites influenced the total particles production during the flaming combustion with changes during kinetics emission. Predominant populations of airborne particles generated during combustion of all tested composites were characterized by a PN50 following by PN(100-500). PMID:26348148

  9. Characterization of aerosol emitted by the combustion of nanocomposites

    NASA Astrophysics Data System (ADS)

    Motzkus, C.; Chivas-Joly, C.; Guillaume, E.; Ducourtieux, S.; Saragoza, L.; Lesenechal, D.; Macé, T.

    2011-07-01

    Day after day, new applications using nanoparticles appear in industry, increasing the probability to find these particles in the workplace as well as in ambient air. As epidemiological studies have shown an association between increased particulate air pollution and adverse health effects in susceptible members of the population, it is particularly important to characterize aerosols emitted by different sources of emission, during the combustion of composites charged with nanoparticles for example. The present study is led in the framework of the NANOFEU project, supported by the French Research Agency (ANR), in order to characterize the fire behaviour of polymers charged with suitable nanoparticles and make an alternative to retardant systems usually employed. To determine the impact of these composites on the emission of airborne particles produced during their combustions, an experimental setup has been developed to measure the mass distribution in the range of 30 nm - 10 μm and the number concentration of submicrometric particles of the produced aerosol. A comparison is performed on the aerosol emitted during the combustion of several polymers alone (PMMA, PA-6), polymers containing nanofillers (silica, alumina, and carbon nanotubes) and polymers containing both nanofillers and a conventional flame retardant system (ammonium polyphosphate). The results on the morphology of particles were also investigated using AFM.

  10. Chemical characterization of aerosol particles by laser Raman spectroscopy. Revision

    SciTech Connect

    Fung, K.H.

    1999-12-01

    The importance of aerosol particles in many branches of science, such as atmospheric chemistry, combustion, interfacial science, and material processing, has been steadily growing during the past decades. One of the unique properties of these particles is the very high surface-to-volume ratios, thus making them readily serve as centers for gas-phase condensation and heterogeneous reactions. These particles must be characterized by size, shape, physical state, and chemical composition. Traditionally, optical elastic scattering has been applied to obtain the physical properties of these particle (e.g., particle size, size distribution, and particle density). These physical properties are particularly important in atmospheric science as they govern the distribution and transport of atmospheric aerosols.

  11. Transport of Aerosols from Asia and Their Radiative Effects Over the Western Pacific: A 3-D Model Study for ACE-Asia Experiment During Spring 2001

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Ginoux, Paul; Flatau, Piotr; Anderson, Tad; Masonis, Sarah; Russell, Phil; Schmid, Beat; Livingston, John; Redemann, Jens; Kahn, Ralph; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    The Aerosol Characterization Experiment-Asia (ACE-Asia) took place in Spring 2001 in the East Asia-West Pacific Ocean. During the ACE-Asia intensive field operation period, high concentrations of dust and anthropogenic aerosols were observed over the Yellow Sea and the Sea of Japan, which were transported out from the Asian continent, with the plume often extending to 6-8 km altitude. The multi-component aerosols originated from Asia are expected to exert a significant radiative forcing over the Pacific region. We present here results from the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model of aerosol transport and radiative forcing in the context of ACE-Asia. The model calculated aerosol concentrations, extinctions, optical thickness, size distributions, and vertical profiles are compared with the aircraft and ship measurements, and the distributions of aerosols are compared with satellite data. The model will be used to understand the origins of the aerosols observed in ACE-Asia, estimate the contributions from anthropogenic and natural aerosols to the total aerosol optical thickness, investigate the effects of humidification and clouds on aerosol properties, and assess the radiative forcing of Asian aerosols over the Pacific region and in the northern hemisphere.

  12. Halogen-induced organic aerosol (XOA): a study on ultra-fine particle formation and time-resolved chemical characterization.

    PubMed

    Ofner, Johannes; Kamilli, Katharina A; Held, Andreas; Lendl, Bernhard; Zetzsch, Cornelius

    2013-01-01

    The concurrent presence of high values of organic SOA precursors and reactive halogen species (RHS) at very low ozone concentrations allows the formation of halogen-induced organic aerosol, so-called XOA, in maritime areas where high concentrations of RHS are present, especially at sunrise. The present study combines aerosol smog-chamber and aerosol flow-reactor experiments for the characterization of XOA. XOA formation yields from alpha-pinene at low and high concentrations of chlorine as reactive halogen species (RHS) were determined using a 700 L aerosol smog-chamber with a solar simulator. The chemical transformation of the organic precursor during the aerosol formation process and chemical aging was studied using an aerosol flow-reactor coupled to an FTIR spectrometer. The FTIR dataset was analysed using 2D correlation spectroscopy. Chlorine induced homogeneous XOA formation takes place at even 2.5 ppb of molecular chlorine, which was photolysed by the solar simulator. The chemical pathway of XOA formation is characterized by the addition of chlorine and abstraction of hydrogen atoms, causing simultaneous carbon-chlorine bond formation. During further steps of the formation process, carboxylic acids are formed, which cause a SOA-like appearance of XOA. During the ozone-free formation of secondary organic aerosol with RHS a special kind of particulate matter (XOA) is formed, which is afterwards transformed to SOA by atmospheric aging or degradation pathways.

  13. Computational modeling and experimental characterization of indoor aerosol transport

    SciTech Connect

    Konecni, S.; Whicker, J. J.; Martin, R. A.

    2002-01-01

    When a hazardous aerosol or gas is inadvertently or deliberately released in an occupied facility, the airborne material presents a hazard to people. Inadvertent accidents and exposures continue to occur in Los Alamos and other nuclear facilities despite state-of-art engineering and administrative controls, and heightened diligence. Despite the obvious need in occupational settings and for homeland defense, the body of research in hazardous aerosol dispersion and control in large, complex, ventilated enclosures is extremely limited. The science governing generation, transport, inhalation, and detection of airborne hazards is lacking and must be developed to where it can be used by engineers or safety professionals in the prediction of worker exposure, in the prevention of accidents, or in the mitigation of terrorist actions. In this study, a commercial computational fluid dynamics (CFD) code, CFX5.4, and experiments were used to assess flow field characteristics, and to investigate aerosol release and transport in a large, ventilated workroom in a facility at Savannah River Site. Steady state CFD results illustrating a complex, ventilation-induced, flow field with vortices, velocity gradients, and quiet zones are presented, as are time-dependent CFD and experimental aerosol dispersion results. The comparison of response times between CFD and experimental results was favorable. It is believed that future applications of CFD and experiments can have a favorable impact on the design of ventilation (HVAC) systems and worker safety with consideration to facility costs. Ultimately, statistical methods will be used in conjunction with CFD calculations to determine the optimal number and location of detectors, as well as optimal egress routes in event of a release.

  14. Aerosol Optical Properties During The SAMUM-2 Experiment

    NASA Astrophysics Data System (ADS)

    Toledano, C.; Freudenthaler, V.; Gross, S.; Seefeldner, M.; Gasteiger, J.; Garhammer, M.; Esselborn, M.; Wiegner, M.; Koepke, P.

    2009-03-01

    A field campaign of the Saharan Mineral Dust Experiment (SAMUM-2) took place in the Cape Verde islands in January-February 2008, to investigate the properties of long-range transported dust over the Atlantic. The Meteorological Institute of the University of Munich deployed a set of active and passive remote sensing instruments: one sun photometer, for the measurement of the direct sun irradiance and sky radiances; a broad-band UV radiometer; and 2 tropospheric lidar systems. The measurements were made in close cooperation with the other participating groups. During the measurement period the aerosol scenario over Cape Verde mostly consisted of a dust layer below 2 km and a smoke layer above 2 km height. The Saharan dust arrived in the site from the NE, whereas the smoke originated in the African equatorial region is transported from the SE. The aerosol load was also very variable over this area, with AOD (500 nm) ranging from 0.04 to 0.74. The optical properties of the layers are shown: extinction and particle depolarization ratio profiles at 3 wavelengths, as well as aerosol optical depth (in the range 340-1550 nm), Ångström exponent, size distribution and single scattering albedo.

  15. The polar ozone and aerosol measurement experiment (POAM II)

    SciTech Connect

    Bevilacqua, R.M.; Shettle, E.P.; Hornstein, J.S.

    1994-12-31

    The Polar Ozone and Aerosol Measurement experiment (POAM II), was launched on the SPOT 3 satellite on 25 September, 1993. POAM II is designed to measure the vertical profiles of the polar ozone, aerosols, water vapor, nitrogen dioxide, atmospheric density and temperature in the stratosphere and upper troposphere. It makes solar occultation measurements in nine channels defined by narrow-band filters. The field of view is 0.01 by 1.2 degrees, with an instantaneous vertical resolution of 0.6 km at the tangent point in the earth`s atmosphere. The SPOT 3 satellite is in a 98.7-degree inclined sun-synchronous orbit at an altitude of 833 km. From the measured transmissions, it is possible to determine the density profiles of aerosols, O{sub 3}, H{sub 2}O, and NO{sub 2}. Using the assumption of uniformly mixed oxygen, the authors are also able to determine the temperature. The authors present details of the POAM II instrument design, including the optical configuration, electronics and measurement accuracy. The authors also present preliminary results from the occultation measurements made to date.

  16. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering. Final technical report

    SciTech Connect

    Aker, P.M.

    1992-12-31

    A research program on the influence of aerosol surface structure on the kinetics of gas-aerosol interactions is proposed. The experiments involve measuring changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol. Aerosols with differing surface properties will be generated by changing the composition and/or temperature of the material making up the aerosol. Kinetic data generated can be used directly in atmospheric modelling calculations. The surface structure of the aerosol will be measured, both before and after reaction, using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Information about the detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during the course of the reaction. Studies will focus on the condensation and oxidation of sulfur species (sulfur dioxide and dimethyl sulfide) on water aerosols.

  17. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering

    SciTech Connect

    Aker, P.M.

    1992-01-01

    A research program on the influence of aerosol surface structure on the kinetics of gas-aerosol interactions is proposed. The experiments involve measuring changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol. Aerosols with differing surface properties will be generated by changing the composition and/or temperature of the material making up the aerosol. Kinetic data generated can be used directly in atmospheric modelling calculations. The surface structure of the aerosol will be measured, both before and after reaction, using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Information about the detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during the course of the reaction. Studies will focus on the condensation and oxidation of sulfur species (sulfur dioxide and dimethyl sulfide) on water aerosols.

  18. Seawater mesocosm experiments in the Arctic uncover differential transfer of marine bacteria to aerosols.

    PubMed

    Fahlgren, Camilla; Gómez-Consarnau, Laura; Zábori, Julia; Lindh, Markus V; Krejci, Radovan; Mårtensson, E Monica; Nilsson, Douglas; Pinhassi, Jarone

    2015-06-01

    Biogenic aerosols critically control atmospheric processes. However, although bacteria constitute major portions of living matter in seawater, bacterial aerosolization from oceanic surface layers remains poorly understood. We analysed bacterial diversity in seawater and experimentally generated aerosols from three Kongsfjorden sites, Svalbard. Construction of 16S rRNA gene clone libraries from paired seawater and aerosol samples resulted in 1294 sequences clustering into 149 bacterial and 34 phytoplankton operational taxonomic units (OTUs). Bacterial communities in aerosols differed greatly from corresponding seawater communities in three out of four experiments. Dominant populations of both seawater and aerosols were Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria. Across the entire dataset, most OTUs from seawater could also be found in aerosols; in each experiment, however, several OTUs were either selectively enriched in aerosols or little aerosolized. Notably, a SAR11 clade OTU was consistently abundant in the seawater, but was recorded in significantly lower proportions in aerosols. A strikingly high proportion of colony-forming bacteria were pigmented in aerosols compared with seawater, suggesting that selection during aerosolization contributes to explaining elevated proportions of pigmented bacteria frequently observed in atmospheric samples. Our findings imply that atmospheric processes could be considerably influenced by spatiotemporal variations in the aerosolization efficiency of different marine bacteria. PMID:25682947

  19. Comparative studies of aerosol extinction measurements made by the SAM II and SAGE II satellite experiments

    NASA Technical Reports Server (NTRS)

    Yue, Glenn K.; Mccormick, M. P.; Chu, W. P.; Wang, P.; Osborn, M. T.

    1989-01-01

    Results from the Stratospheric Aerosol Measurement (SAM) II and Stratospheric Aerosol and Gas Experiment (SAGE) II are compared for measurement locations which are coincident in time and space. At 1.0 micron, the SAM II and SAGE II aerosol extinction profiles are similar within their measurement errors. In addition, sunrise and sunset aerosol extinction data at four different wavelengths are compared for occasions when the SAGE II and SAM II measurements are nearly coincident in space and about 12 hours apart.

  20. Characterization of aerosol particles at the forested site in Lithuania

    NASA Astrophysics Data System (ADS)

    Rimselyte, I.; Garbaras, A.; Kvietkus, K.; Remeikis, V.

    2009-04-01

    Atmospheric particulate matter (PM), especially fine particles (particles with aerodynamic diameter less than 1 m, PM1), has been found to play an important role in global climate change, air quality, and human health. The continuous study of aerosol parameters is therefore imperative for better understanding the environmental effects of the atmospheric particles, as well as their sources, formation and transformation processes. The particle size distribution is particularly important, since this physical parameter determines the mass and number density, lifetime and atmospheric transport, or optical scattering behavior of the particles in the atmosphere (Jaenicke, 1998). Over the years several efforts have been made to improve the knowledge about the chemical composition of atmospheric particles as a function of size (Samara and Voutsa, 2005) and to characterize the relative contribution of different components to the fine particulate matter. It is well established that organic materials constitute a highly variable fraction of the atmospheric aerosol. This fraction is predominantly found in the fine size mode in concentrations ranging from 10 to 70% of the total dry fine particle mass (Middlebrook et al., 1998). Although organic compounds are major components of the fine particles, the composition, formation mechanism of organic aerosols are not well understood. This is because particulate organic matter is part of a complex atmospheric system with hundreds of different compounds, both natural and anthropogenic, covering a wide range of chemical properties. The aim of this study was to characterize the forest PM1, and investigate effects of air mass transport on the aerosol size distribution and chemical composition, estimate and provide insights into the sources and characteristics of carbonaceous aerosols through analysis ^13C/12C isotopic ratio as a function of the aerosol particles size. The measurements were performed at the Rugšteliškis integrated

  1. A strategy for characterizing the mixing state of immiscible aerosol components and the formation of multiphase aerosol particles through coagulation.

    PubMed

    Mitchem, Laura; Buajarern, Jariya; Ward, Andrew D; Reid, Jonathan P

    2006-07-20

    We demonstrate that the coagulation of two aerosol droplets of different chemical composition can be studied directly through the unique combination of optical tweezers and Raman spectroscopy. Multiple optical traps can be established, allowing the manipulation of multiple aerosol droplets. Spontaneous Raman scattering allows the characterization of droplet composition and mixing state, permitting the phase segregation of immiscible components in multiphase aerosol to be investigated with spatial resolution. Stimulated Raman scattering allows the integrity of the droplet and uniformity of refractive index to be probed. The combination of these spectroscopic probes with optical tweezers is shown to yield unprecedented detail in studies of the coagulation of decane and water droplets.

  2. Generation and characterization of large-particle aerosols using a center flow tangential aerosol generator with a nonhuman-primate, head-only aerosol chamber

    PubMed Central

    Bohannon, J. Kyle; Lackemeyer, Matthew G.; Kuhn, Jens H.; Wada, Jiro; Bollinger, Laura; Jahrling, Peter B.; Johnson, Reed F.

    2016-01-01

    Aerosol droplets or particles produced from infected respiratory secretions have the potential to infect another host through inhalation. These respiratory particles can be polydisperse and range from 0.05–500 μm in diameter. Animal models of infection are generally established to facilitate the potential licensure of candidate prophylactics and/or therapeutics. Consequently, aerosol-based animal infection models are needed to properly study and counter airborne infections. Ideally, experimental aerosol exposure should reliably result in animal disease that faithfully reproduces the modelled human disease. Few studies have been performed to explore the relationship between exposure particle size and induced disease course for infectious aerosol particles. The center flow tangential aerosol generator (CenTAG™) produces large-particle aerosols capable of safely delivering a variety of infectious aerosols to nonhuman primates within a Class III Biological Safety Cabinet (BSC) for establishment or refinement of nonhuman primate infectious disease models. Here we report the adaptation of this technology to the Animal Biosafety Level 4 (ABSL-4) environment for the future study of high-consequence viral pathogens and the characterization of CenTAG™-created sham (no animal, no virus) aerosols using a variety of viral growth media and media supplements. PMID:25970823

  3. Generation and characterization of large-particle aerosols using a center flow tangential aerosol generator with a non-human-primate, head-only aerosol chamber.

    PubMed

    Bohannon, J Kyle; Lackemeyer, Matthew G; Kuhn, Jens H; Wada, Jiro; Bollinger, Laura; Jahrling, Peter B; Johnson, Reed F

    2015-01-01

    Aerosol droplets or particles produced from infected respiratory secretions have the potential to infect another host through inhalation. These respiratory particles can be polydisperse and range from 0.05 to 500 µm in diameter. Animal models of infection are generally established to facilitate the potential licensure of candidate prophylactics and/or therapeutics. Consequently, aerosol-based animal infection models are needed to properly study and counter airborne infections. Ideally, experimental aerosol exposure should reliably result in animal disease that faithfully reproduces the modeled human disease. Few studies have been performed to explore the relationship between exposure particle size and induced disease course for infectious aerosol particles. The center flow tangential aerosol generator (CenTAG™) produces large-particle aerosols capable of safely delivering a variety of infectious aerosols to non-human primates (NHPs) within a Class III Biological Safety Cabinet (BSC) for establishment or refinement of NHP infectious disease models. Here, we report the adaptation of this technology to the Animal Biosafety Level 4 (ABSL-4) environment for the future study of high-consequence viral pathogens and the characterization of CenTAG™-created sham (no animal, no virus) aerosols using a variety of viral growth media and media supplements. PMID:25970823

  4. 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.

  5. Synergic use of TOMS and AERONET observations for characterization of aerosol absorption

    NASA Astrophysics Data System (ADS)

    Torres, O.; Sinyuk, A.; Bhartia, P. K.; Dubovik, O.; Holben, B.

    2003-04-01

    The role of aerosol absorption on the radiative transfer balance of the earth-atmosphere system is one of the largest sources of uncertainty in the analysis of global climate change. Global measurements of aerosol single scattering albedo are, therefore, necessary to properly assess the radiative forcing effect of aerosols. Remote sensing of aerosol absorption is currently carried out using both ground (Aerosol Robotic Network) and space (Total Ozone Mapping Spectrometer) based observations. The satellite technique uses measurements of backscattered near ultraviolet radiation. Carbonaceous aerosols, resulting from the combustion of biomass, are one of the most predominant absorbing aerosol types in the atmosphere. In this presentation, TOMS and AERONET retrievals of single scattering albedo of carbonaceous aerosols, are compared for different environmental conditions: agriculture related biomass burning in South America and Africa and peat fires in Eastern Europe. The AERONET and TOMS derived aerosol absorption information are in good quantitative agreement. The most absorbing smoke is detected over the African Savanna. Aerosol absorption over the Brazilian rain forest is less absorbing. Absorption by aerosol particles resulting from peat fires in Eastern Europe is weaker than the absorption measured in Africa and South America. This analysis shows that the near UV satellite method of aerosol absorption characterization has the sensitivity to distinguish different levels of aerosol absorption. The analysis of the combined AERONET-TOMS observations shows a high degree of synergy between satellite and ground based observations.

  6. Synergic use of TOMS and Aeronet Observations for Characterization of Aerosol Absorption

    NASA Technical Reports Server (NTRS)

    Torres, O.; Bhartia, P. K.; Dubovik, O.; Holben, B.; Siniuk, A.

    2003-01-01

    The role of aerosol absorption on the radiative transfer balance of the earth-atmosphere system is one of the largest sources of uncertainty in the analysis of global climate change. Global measurements of aerosol single scattering albedo are, therefore, necessary to properly assess the radiative forcing effect of aerosols. Remote sensing of aerosol absorption is currently carried out using both ground (Aerosol Robotic Network) and space (Total Ozone Mapping Spectrometer) based observations. The satellite technique uses measurements of backscattered near ultraviolet radiation. Carbonaceous aerosols, resulting from the combustion of biomass, are one of the most predominant absorbing aerosol types in the atmosphere. In this presentation, TOMS and AERONET retrievals of single scattering albedo of carbonaceous aerosols, are compared for different environmental conditions: agriculture related biomass burning in South America and Africa and peat fires in Eastern Europe. The AERONET and TOMS derived aerosol absorption information are in good quantitative agreement. The most absorbing smoke is detected over the African Savanna. Aerosol absorption over the Brazilian rain forest is less absorbing. Absorption by aerosol particles resulting from peat fires in Eastern Europe is weaker than the absorption measured in Africa and South America. This analysis shows that the near UV satellite method of aerosol absorption characterization has the sensitivity to distinguish different levels of aerosol absorption. The analysis of the combined AERONET-TOMS observations shows a high degree of synergy between satellite and ground based observations.

  7. Molecular Characterization of Nitrogen Containing Organic Compounds in Biomass Burning Aerosols Using High Resolution Mass Spectrometry

    SciTech Connect

    Laskin, Alexander; Smith, Jeffrey S.; Laskin, Julia

    2009-05-13

    Although nitrogen-containing organic compounds (NOC) are important components of atmospheric aerosols, little is known about their chemical compositions. Here we present detailed characterization of the NOC constituents of biomass burning aerosol (BBA) samples using high resolution electrospray ionization mass spectrometry (ESI/MS). Accurate mass measurements combined with MS/MS fragmentation experiments of selected ions were used to assign molecular structures to individual NOC species. Our results indicate that N-heterocyclic alkaloid compounds - species naturally produced by plants and living organisms - comprise a substantial fraction of NOC in BBA samples collected from test burns of five biomass fuels. High abundance of alkaloids in test burns of ponderosa pine - a widespread tree in the western U.S. areas frequently affected by large scale fires - suggests that N-heterocyclic alkaloids in BBA can play a significant role in dry and wet deposition of fixed nitrogen in this region.

  8. Characterization of a Photoacoustic Aerosol Absorption Spectrometer for Aircraft-based Measurements

    NASA Astrophysics Data System (ADS)

    Mason, B. J.; Wagner, N. L.; Richardson, M.; Brock, C. A.; Murphy, D. M.; Adler, G.

    2015-12-01

    Atmospheric aerosol directly impacts the Earth's climate through extinction of incoming and outgoing radiation. The optical extinction is due to both scattering and absorption. In situ measurements of aerosol extinction and scattering are well established and have uncertainties less than 5%. However measurements of aerosol absorption typically have uncertainties of 20-30%. Development and characterization of more accurate and precise instrumentation for measurement of aerosol absorption will enable a deeper understand of significance and spatial distribution of black and brown carbon aerosol, the effect of atmospheric processes on aerosol optical properties, and influence of aerosol optical properties on direct radiative forcing. Here, we present a detailed characterization of a photoacoustic aerosol absorption spectrometer designed for deployment aboard research aircraft. The spectrometer operates at three colors across the visible spectrum and is calibrated in the field using ozone. The field calibration is validated in the laboratory using synthetic aerosol and simultaneous measurements of extinction and scattering. In addition, the sensitivity of the instrument is characterized under conditions typically encountered during aircraft sampling e.g. as a function of changing pressure. We will apply this instrument characterization to ambient aerosol absorption data collected during the SENEX and SEAC4RS aircraft based field campaigns.

  9. 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.

  10. High-Resolution Desorption Electrospray Ionization Mass Spectrometry for Chemical Characterization of Organic Aerosols

    SciTech Connect

    Laskin, Julia; Laskin, Alexander; Roach, Patrick J.; Slysz, Gordon W.; Anderson, Gordon A.; Nizkorodov, Serguei; Bones, David L.; Nguyen, Lucas

    2010-03-01

    Characterization of the chemical composition and chemical transformations of secondary organic aerosol (SOA) is both a major challenge and the area of greatest uncertainty in current aerosol research. This study presents the first application of desorption electrospray ionization combined with high-resolution mass spectrometry (DESI-MS) for detailed chemical characterization and studies of chemical aging of OA collected on Teflon substrates. DESI-MS offers unique advantages both for detailed characterization of chemically labile components in OA that cannot be detected using more traditional electrospray ionization mass spectrometry (ESI-MS) and for studying chemical aging of OA. DESI-MS enables rapid characterization of OA samples collected on substrates by eliminating the sample preparation stage. In addition, it enables detection and structural characterization of chemically labile molecules in OA samples by minimizing the residence time of analyte in the solvent. SOA produced by the ozonolysis of limonene (LSOA) was allowed to react with gaseous ammonia. Chemical aging resulted in measurable changes in the optical properties of LSOA observed using UV- visible spectroscopy. DESI-MS combined with tandem mass spectrometry experiments (MS/MS) enabled identification of species in aged LSOA responsible for absorption of the visible light. Detailed analysis of the experimental data allowed us to identify chemical changes induced by reactions of LSOA constituents with ammonia and distinguish between different mechanisms of chemical aging.

  11. Molecular Characterization of Secondary Aerosol from Oxidation of Cyclic Methylsiloxanes

    NASA Astrophysics Data System (ADS)

    Wu, Yue; Johnston, Murray V.

    2016-03-01

    Cyclic volatile methylsiloxanes (cVMS) have been identified as important gas-phase atmospheric contaminants, but knowledge of the molecular composition of secondary aerosol derived from cVMS oxidation is incomplete. Here, the chemical composition of secondary aerosol produced from the OH-initiated oxidation of decamethylcyclopentasiloxane (D5, C10H30O5Si5) is characterized by high performance mass spectrometry. ESI-MS reveals a large number of monomeric (300 < m/z < 470) and dimeric (700 < m/z < 870) oxidation products. With the aid of high resolution and MS/MS, it is shown that oxidation leads mainly to the substitution of a CH3 group by OH or CH2OH, and that a single molecule can undergo many CH3 group substitutions. Dimers also exhibit OH and CH2OH substitutions and can be linked by O, CH2, and CH2CH2 groups. GC-MS confirms the ESI-MS results. Oxidation of D4 (C8H24O4Si4) exhibits similar substitutions and oligomerizations to D5, though the degree of oxidation is greater under the same conditions and there is direct evidence for the formation of peroxy groups (CH2OOH) in addition to OH and CH2OH.

  12. Molecular Characterization of Secondary Aerosol from Oxidation of Cyclic Methylsiloxanes.

    PubMed

    Wu, Yue; Johnston, Murray V

    2016-03-01

    Cyclic volatile methylsiloxanes (cVMS) have been identified as important gas-phase atmospheric contaminants, but knowledge of the molecular composition of secondary aerosol derived from cVMS oxidation is incomplete. Here, the chemical composition of secondary aerosol produced from the OH-initiated oxidation of decamethylcyclopentasiloxane (D5, C10H30O5Si5) is characterized by high performance mass spectrometry. ESI-MS reveals a large number of monomeric (300 < m/z < 470) and dimeric (700 < m/z < 870) oxidation products. With the aid of high resolution and MS/MS, it is shown that oxidation leads mainly to the substitution of a CH3 group by OH or CH2OH, and that a single molecule can undergo many CH3 group substitutions. Dimers also exhibit OH and CH2OH substitutions and can be linked by O, CH2, and CH2CH2 groups. GC-MS confirms the ESI-MS results. Oxidation of D4 (C8H24O4Si4) exhibits similar substitutions and oligomerizations to D5, though the degree of oxidation is greater under the same conditions and there is direct evidence for the formation of peroxy groups (CH2OOH) in addition to OH and CH2OH. PMID:26729452

  13. Extending the performances of stratospheric aerosol characterization in the 2002-2011 period through data merging of GOMOS and OSIRIS measurements

    NASA Astrophysics Data System (ADS)

    Bingen, Christine; Robert, Charles; Vanhellemont, Filip; Mateshvili, Nina; Dekemper, Emmanuel; Fussen, Didier; Bourassa, Adam

    2016-04-01

    Stratospheric extinction and size information are two important aerosol parameters used to model the role of stratospheric aerosols in the atmospheric system, and to assess the respective importance of volcanic and anthropogenic aerosols. Since the historical aerosol minimum in 1998-2000, several remote sensing experiments have provided radiative aerosol measurements, using various and often challenging measurement principles, and, for each of them, a specific set of spectral channels. This results in a rich patchwork of spectral information presenting gaps and discontinuities in space, time, and wavelength. Acquiring aerosol size information on a global scale is a very challenging task. Such information can be retrieved by radial inversion of the extinction spectrum, but this task is often a struggle due to the reduced number of spectral channels and mainly to a limitation of the spectral range. Combining aerosol radiative measurements from multiple remote experiments seems to be a promising way to provide modellers with an improved characterization of the aerosol extinction and size information they need. This work presents the current status of the development of merged aerosol datasets from the GOMOS and OSIRIS experiments. After presenting the methodology used for the data merging, we will present the latest results obtained in this study and show how the performances of the merged dataset can improve with respect to the ones of each of the individual retrievals.

  14. CURRENT AND EMERGING TECHNIQUES FOR CHARACTERIZING TROPOSPHERIC AEROSOLS

    EPA Science Inventory

    Particulate matter generally includes dust, smoke, soot, or aerosol particles. Environmental research addresses the origin, size, chemical composition, and the formation mechanics of aerosols. In the troposphere, fine aerosols (e.g. with diameters < 2.5 um) remain suspended until...

  15. Aerosol Characterization and New Instrumentation for Better Understanding Snow Radiative Properties

    NASA Astrophysics Data System (ADS)

    Beres, N. D.

    2015-12-01

    Snow albedo is determined by snowpack thickness and grain size, but also affected by contamination with light-absorbing, microscopic (e.g., mineral dust, combustion aerosols, bio-aerosols) and macroscopic (e.g., microalgae, plant debris, sand, organisms) compounds. Most currently available instruments for measuring snow albedo utilize the natural, downward flux of solar radiation and the reflected upward flux. This reliance on solar radiation (and, thus, large zenith angles and clear-sky conditions) leads to severe constraints, preventing characterization of detailed diurnal snow albedo cycles. Here, we describe instrumentation and methodologies to address these limitations with the development and deployment of new snow radiation sensors for measuring surface spectral and in-snow radiative properties. This novel instrumentation will be tested at the CRREL/UCSB Eastern Sierra (CUES) Snow Study Site at Mammoth Mountain, which is extensively instrumented for characterizing snow properties including snow albedo and surface morphology. However, it has been lacking instrumentation for the characterization of aerosols that can be deposited on the snow surface through dry and wet deposition. Currently, we are installing aerosol instrumentation at the CUES site, which are also described. This includes instruments for the multi-wavelength measurement of aerosol scattering and absorption coefficients and for the characterization of aerosol size distribution. Knowledge of aerosol concentration and physical and optical properties will allow for the study of aerosol deposition and modification of snow albedo and for establishing an aerosol climatology for the CUES site.

  16. Laboratory Experiments and Instrument Development for the Study of Atmospheric Aerosols

    SciTech Connect

    Davidovits, Paul

    2011-12-10

    -cost extension period) of our grant, we extended our studies to perform experiments on the controlled production and characterization of secondary organic aerosol.

  17. Characterization of Spectral Absorption Properties of Aerosols Using Satellite Observations

    NASA Technical Reports Server (NTRS)

    Torres, O.; Jethva, H.; Bhartia, P. K.; Ahn, C.

    2012-01-01

    The wavelength-dependence of aerosol absorption optical depth (AAOD) is generally represented in terms of the Angstrom Absorption Exponent (AAE), a parameter that describes the dependence of AAOD with wavelength. The AAE parameter is closely related to aerosol composition. Black carbon (BC) containing aerosols yield AAE values near unity whereas Organic carbon (OC) aerosol particles are associated with values larger than 2. Even larger AAE values have been reported for desert dust aerosol particles. Knowledge of spectral AAOD is necessary for the calculation of direct radiative forcing effect of aerosols and for inferring aerosol composition. We have developed a satellitebased method of determining the spectral AAOD of absorbing aerosols. The technique uses high spectral resolution measurements of upwelling radiation from scenes where absorbing aerosols lie above clouds as indicated by the UV Aerosol Index. For those conditions, the satellite measured reflectance (rho lambda) is approximately given by Beer's law rho lambda = rho (sub 0 lambda) e (exp -mtau (sub abs lambda)) where rho(sub 0 lambda) is the cloud reflectance, m is the geometric slant path and tau (sub abs lambda) is the spectral AAOD. The rho (sub 0 lambda) term is determined by means of radiative transfer calculations using as input the cloud optical depth derived as described in Torres et al. [JAS, 2012] that accounts for the effects of aerosol absorption. In the second step, corrections for molecular and aerosol scattering effects are applied to the cloud reflectance term, and the spectral AAOD is then derived by inverting the equation above. The proposed technique will be discussed in detail and application results will be presented. The technique can be easily applied to hyper-spectral satellite measurements that include UV such as OMI, GOME and SCIAMACHY, or to multi-spectral visible measurements by other sensors provided that the aerosol-above-cloud events are easily identified.

  18. Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

    2012-07-01

    Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

  19. Communications Link Characterization Experiment (CLCE)

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Results of the data which were acquired, reduced, and analyzed from the Communications Link Characterization Experiment (CLCE) while utilizing the CTS satellite are presented. The test data obtained from the stations consisted of the results of various TV tests, attenuation and rain rate data. An additional meteorological parameter was measured and it consists of the back scatter returns of the multifrequency weather radar.

  20. Feasibility of polarized all-sky imaging for aerosol characterization

    NASA Astrophysics Data System (ADS)

    Kreuter, A.; Blumthaler, M.

    2012-12-01

    Polarized all-sky distribution measurements contain radiative information about aerosol properties. We investigate the method of all-sky imaging for aerosol property retrieval and propose a technical frame work for image processing and analysis. Using Zernike polynomials, we decompose the relative Stokes parameter distributions, which efficiently captures the information content. The resulting feature vector is well suited for all-sky imaging, independent of calibration and robust against noise. It can be directly used in existing algorithms or alternative types of retrieval methods of aerosol optical properties in the future. By modeling possible aerosol scenarios we investigate the influence of different aerosol types in terms of the first two principal components describing the maximal variances. In this representation we show that the feature vector from a polarized all-sky imager is suitable for aerosol classification with respect to size and single scatter albedo.

  1. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; Denjean, C.; Brogniez, G.; di Sarra, A.; Alados-Arboledas, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, T.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Waquet, F.; Wenger, J.; Zapf, P.

    2016-01-01

    levels of atmospheric pollutants or intense biomass burning events in the region. However, numerous mineral dust plumes were observed during the campaign, with the main sources located in Morocco, Algeria and Tunisia, leading to aerosol optical depth (AOD) values ranging between 0.2 and 0.6 (at 440 nm) over the western and central Mediterranean basins. One important point of this experiment concerns the direct observations of aerosol extinction onboard the ATR-42, using the CAPS system, showing local maxima reaching up to 150 M m-1 within the dust plume. Non-negligible aerosol extinction (about 50 M m-1) has also been observed within the marine boundary layer (MBL). By combining the ATR-42 extinction coefficient observations with absorption and scattering measurements, we performed a complete optical closure revealing excellent agreement with estimated optical properties. This additional information on extinction properties has allowed calculation of the dust single scattering albedo (SSA) with a high level of confidence over the western Mediterranean. Our results show a moderate variability from 0.90 to 1.00 (at 530 nm) for all flights studied compared to that reported in the literature on this optical parameter. Our results underline also a relatively low difference in SSA with values derived near dust sources. In parallel, active remote-sensing observations from the surface and onboard the F-20 aircraft suggest a complex vertical structure of particles and distinct aerosol layers with sea spray and pollution located within the MBL, and mineral dust and/or aged North American smoke particles located above (up to 6-7 km in altitude). Aircraft and balloon-borne observations allow one to investigate the vertical structure of the aerosol size distribution showing particles characterized by a large size (> 10 µm in diameter) within dust plumes. In most of cases, a coarse mode characterized by an effective diameter ranging between 5 and 10 µm, has been detected above the

  2. Comparison of In Situ Aerosol Data from the ACE-Asia 2001 Experiment

    NASA Astrophysics Data System (ADS)

    Knobelspiesse, K. D.; Pietras, C.; Miller, M. A.; Reynolds, R. M.; Frouin, R.; Quinn, P. K.; Deschamps, P. Y.; Werdell, P. J.; Fargion, G. S.

    2002-05-01

    The Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) is an international, multidisciplinary project to further knowledge about atmospheric aerosols. ACE-Asia included an intensive field measurement campaign during the spring of 2001 off the coasts of China, Japan and Korea. The Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project participated in the ACE-Asia cruise of the R/V Ronald H. Brown, which departed from Hawaii on 2001/03/15, sailed west to the Sea of Japan, and finished in Yokosuka, Japan on 2001/04/19. The SIMBIOS Project compares and merges data projects from multiple ocean color missions. As In Situ data are essential for merger and comparison of satellite ocean color measurements, the Project is interested in instrumentation devopment and data base building. The SeaWiFS Bio-optical Archive and Storage System (SeaBASS) is the database used and maintained by the SIMBIOS project. The ACE-Asia cruise was an excellent opportunity to compare data from a variety of maritime sun photometers, as several aerosol conditions were experienced. These included low Aerosol Optical Thickness (AOT) maritime conditions near Hawaii and extremely high AOT dust conditions in the Sea of Japan. Concurrant measurements were made with the PREDE POM-01 Mark II radiometer, a Laboratoire d'Optique Atmosphérique (LOA) SIMBAD, a Laboratorie d'Optique Atmosphérique (LOA) SIMBAD-a, two Solar Light, Inc. Microtops II's, and Brookhaven National Laboratory's Fast Rotating Shadowband Radiometer (FRSR). In addition, a Micro Pulse Lidar (MPL) was deployed that provides vertical aerosol distributions. Data were processed utilizing new algorithms to screen errors due to improper pointing at the sun, a problem previously recognized for the Microtops II. Comparisons of AOT at 500nm and Angstrom Exponent were made for all the instruments. The hand held, direct solar sun photometers (Microtops II, SIMBAD and SIMBADa

  3. Characterizing the Vertical Distribution of Aerosols Over the ARM SGP Site

    SciTech Connect

    Richard Ferrare, Connor Flynn, David Turner

    2009-05-05

    . Analysis of the aerosol and water vapor data collected by the Raman lidar during the 2003 Aerosol IOP indicated that the sensitivity of the lidar was significantly lower than when the lidar was initially deployed. A detailed analysis after the IOP of the long-term dataset demonstrated that the lidar began degrading in early 2002, and that it lost approximately a factor of 4 in sensitivity between 2002 and 2004. We participated in the development of the remediation plan for the system to restore its initial performance. We conducted this refurbishment and upgrade from May- September 2004. This remediation lead to an increase in the signal-to-noise ratio of 10 and 30 for the Raman lidar's water vapor mixing ratio and aerosol backscatter coefficient data, respectively as compared to the signal strengths when the system was first deployed. The DOE ARM Aerosol Lidar Validation Experiment (ALIVE), which was conducted during September 2005, evaluated the impact of these modifications and upgrades on the SGP Raman lidar measurements of aerosol extinction and optical thickness. The CARL modifications significantly improved the accuracy and temporal resolution of the aerosol measurements. Aerosol extinction profiles measured by the Raman lidar were also used to evaluate aerosol extinction profiles and aerosol optical thickness (AOT) simulated by aerosol models as part of the Aerosol module inter-Comparison in global models (AEROCOM) (http://nansen.ipsl.jussieu.fr/AEROCOM/aerocomhome.html) project. There was a wide range in how the models represent the aerosol extinction profiles over the ARM SGP site, even though the average annual AOT represented by the various models and measured by CARL and the Sun photometer were in general agreement, at least within the standard deviations of the averages. There were considerable differences in the average vertical distributions among the models, even among models that had similar average aerosol optical thickness. Deviations between mean

  4. Characterizing Uncertainty in Global Aerosol Retrievals from Multiple Spaceborne Sensors

    NASA Astrophysics Data System (ADS)

    Petrenko, M.; Smirnov, A.; Ichoku, C. M.

    2014-12-01

    Complementary global aerosol products have been routinely available from multiple spaceborne sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, SeaWiFS, and VIIRS. However, a variety of studies suggest that individual aerosol products have significant differences in the geographic distribution of their retrieval uncertainties. Nonetheless, it can be difficult or impractical to track down relevant product validation studies and invest time in mastering the proprietary file formats of these aerosol products. As a result, many studies are performed using data from one or two most familiar products that, oftentimes, may not be optimal for a given region of interest. In this presentation, we will use Aerosol Robotic Network (AERONET) and Maritime Aerosol Network (MAN) data within the framework of the Multi-sensor Aerosol Products Sampling System (MAPSS) to catalog the accuracy of aerosol retrievals from the spaceborne sensors listed above. We will report our findings in analyzing the spatial and temporal distributions of the uncertainties in the global over-land and maritime retrievals of aerosols based on inter-comparing spaceborne data with coincident ground-based measurements from both AERONET and MAN. We will also explain our vision of how this analysis can be used as a base for a multi-sensor aerosol product package that would help end users to make a more informed choice when selecting data for their regions of interest.

  5. Characterization of particleboard aerosol - size distribution and formaldehyde content

    SciTech Connect

    Stumpf, J.M.; Blehm, K.D.; Buchan, R.M.; Gunter, B.J.

    1986-12-01

    Health hazards unique to particleboard include the generation of urea-formaldehyde resin bound in wood aerosol and release of formaldehyde gas that can be inhaled by the worker. A particleboard aerosol was generated by a sanding process and collected under laboratory conditions that determined the particle size distribution and formaldehyde content. Three side-by-side Marple 296 personal cascade impactors with midget impingers attached downstream collected particleboard aerosol and gaseous formaldehyde for ten sample runs. Gravimetric analysis quantified the collected aerosol mass, and chromotropic acid/spectrophotometric analytical methods were employed for formaldehyde content in particleboard aerosol and gaseous formaldehyde liberated from sanded particleboard. Significant variations (p<.005) were observed for the particleboard mass and gaseous formaldehyde collected between sample runs. No significant differences (..cap alpha.. = .05) were observed for the aerosol size distribution determined and formaldehyde content in particle board aerosol per unit mass for sampling trials. The overall MMAD of particleboard aerosol was 8.26 ..mu..mAED with a sigmag of 2.01. A predictive model was derived for determining the expected formaldehyde content (..mu..g) by particleboard aerosol mass (mg) collected and particulate size (..mu..mAED).

  6. A comparative study of aerosol extinction measurements made by the SAM II and SAGE satellite experiments

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Mccormick, M. P.; Chu, W. P.

    1984-01-01

    SAM II and SAGE are two satellite experiments designed to measure stratospheric aerosol extinction using the technique of solar occultation or limb extinction. Although each sensor is mounted aboard a different satellite, there are occasions when their measurement locations are nearly coincident, thereby providing opportunities for a measurement comparison. In this paper, the aerosol extinction profiles and daily contour plots for some of these events in 1979 are reported. The comparisons shown in this paper demonstrate that SAM II and SAGE are producing similar aerosol extinction profiles within their measurement errors and that since SAM II has been previously validated, these results show the validity of the SAGE aerosol measurements.

  7. Microanalysis of the aerosol collected over south-central New Mexico during the alive field experiment, May-December 1989

    NASA Astrophysics Data System (ADS)

    Sheridan, Patrick J.; Schnell, Russel C.; Kahl, Jonathan D.; Boatman, Joe F.; Garvey, Dennis M.

    Thirty-eight size-segregated aerosol samples were collected in the lower troposphere over the high desert of south-central New Mexico, using cascade impactors mounted onboard two research aircraft. Four of these samples were collected in early May, sixteen in mid-July, and the remaining ones in December 1989, during three segments of the ALIVE field initiative. Analytical electron microscope analyses of aerosol deposits and individual particles from these samples were performed to physically and chemically characterize the major particulate species present in the aerosol. Air-mass trajectories arriving at the sampling area in the May program were quite different from those calculated for the July period. In general, the May trajectories showed strong westerly winds, while the July winds were weaker and southerly, consistently passing over or very near the border cities of El Paso, Texas, and Ciudad Juarez, Mexico. Aerosol samples collected during the May period were predominantly fine (0.1-0.5 μm dia.), liquid H 2SO 4 droplets. Samples from the July experiment were comprised mostly of fine, solid (NH 4) 2SO 4 or mostly neutralized sulfate particles. In both sampling periods, numerous other particle classes were observed, including many types with probable terrestrial or anthropogenic sources. The numbers of these particles, however, were small when compared with the sulfates. Composite particle types, including sulfate/crustal and sulfate/carbonaceous, were also found to be present. The major differences in aerosol composition between the May and July samples (i.e. the extensive neutralization of sulfates in the July samples) can be explained by considering the different aerosol transport pathways and the proximity of the July aerosol to the El Paso/Juarez urban plume. Winds during the December experiment were quite variable, and may have contributed to the widely varying aerosol compositions observed in these samples. When the aircraft sampled the El Paso

  8. Intercomparison and closure calculations using measurements of aerosol species and optical properties during the Yosemite Aerosol Characterization Study

    NASA Astrophysics Data System (ADS)

    Malm, William C.; Day, Derek E.; Carrico, Christian; Kreidenweis, Sonia M.; Collett, Jeffrey L.; McMeeking, Gavin; Lee, Taehyoung; Carrillo, Jacqueline; Schichtel, Bret

    2005-07-01

    Physical and optical properties of inorganic aerosols have been extensively studied, but less is known about carbonaceous aerosols, especially as they relate to the non-urban settings such as our nation's national parks and wilderness areas. Therefore an aerosol characterization study was conceived and implemented at one national park that is highly impacted by carbonaceous aerosols, Yosemite. The primary objective of the study was to characterize the physical, chemical, and optical properties of a carbon-dominated aerosol, including the ratio of total organic matter weight to organic carbon, organic mass scattering efficiencies, and the hygroscopic characteristics of a carbon-laden ambient aerosol, while a secondary objective was to evaluate a variety of semi-continuous monitoring systems. Inorganic ions were characterized using 24-hour samples that were collected using the URG and Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring systems, the micro-orifice uniform deposit impactor (MOUDI) cascade impactor, as well as the semi-continuous particle-into-liquid sampler (PILS) technology. Likewise, carbonaceous material was collected over 24-hour periods using IMPROVE technology along with the thermal optical reflectance (TOR) analysis, while semi-continuous total carbon concentrations were measured using the Rupprecht and Patashnick (R&P) instrument. Dry aerosol number size distributions were measured using a differential mobility analyzer (DMA) and optical particle counter, scattering coefficients at near-ambient conditions were measured with nephelometers fitted with PM10 and PM2.5 inlets, and "dry" PM2.5 scattering was measured after passing ambient air through Perma Pure Nafion® dryers. In general, the 24-hour "bulk" measurements of various aerosol species compared more favorably with each other than with the semi-continuous data. Semi-continuous sulfate measurements correlated well with the 24-hour measurements, but were biased low by

  9. Organic Aerosol Formation in the Humid, Photochemically-Active Southeastern US: SOAS Experiments and Simulations

    NASA Astrophysics Data System (ADS)

    Sareen, N.; Lim, Y. B.; Carlton, A. G.; Turpin, B. J.

    2013-12-01

    Aqueous multiphase chemistry in the atmosphere can lead to rapid transformation of organic compounds, forming highly oxidized low volatility organic aerosol and, in some cases, light absorbing (brown) carbon. Because liquid water is globally abundant, this chemistry could substantially impact climate, air quality, health, and the environment. Gas-phase precursors released from biogenic and anthropogenic sources are oxidized and fragmented forming water-soluble gases that can undergo reactions in the aqueous phase (in clouds, fogs, and wet aerosols) leading to the formation of secondary organic aerosol (SOAAQ). Recent studies have highlighted the role of certain precursors like glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone, and epoxides in the formation of SOAAQ. The goal of this work is to identify other precursors that are atmospherically important. In this study, ambient mixtures of water-soluble gases were scrubbed from the atmosphere at Brent, Alabama during the Southern Oxidant and Aerosol Study (SOAS). Four mist chambers in parallel collected ambient gases in a DI water medium at 20-25 LPM with a 4 hr collection time. Total organic carbon (TOC) values in daily composited samples were 64-180 μM. Aqueous OH radical oxidation experiments were conducted with these mixtures in a newly designed cuvette chamber to understand the formation of SOA through gas followed by aqueous chemistry. OH radicals (3.5E-2 μM [OH] s-1) were formed in-situ in the chamber, continuously by H2O2 photolysis. Precursors and products of these aqueous OH experiments were characterized using ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS), and IC-ESI-MS. ESI-MS results from a June 12th, 2013 sample showed precursors to be primarily odd, positive mode ions, indicative of the presence of non-nitrogen containing alcohols, aldehydes, organic peroxides, or epoxides. Products were seen in the negative mode and included organic acid ions like pyruvate

  10. Molecular Characterization of Organic Aerosols Using Nanospray Desorption/Electrospray Ionization-Mass Spectrometry

    SciTech Connect

    Roach, Patrick J.; Laskin, Julia; Laskin, Alexander

    2010-10-01

    Nanospray desorption electrospray ionization (Nano-DESI) combined with high-resolution mass spectrometry (HR/MS) is a promising approach for detailed chemical characterization of atmospheric organic aerosol (OA) collected in laboratory and field experiments. In Nano-DESI analyte is desorbed into a solvent bridge formed between two capillaries and the analysis surface, which enables fast and efficient characterization of OA collected on substrates without special sample preparation. Stable signals achieved using Nano-DESI make it possible to obtain high-quality HR/MS data using only a small amount of material (<10 ng). Furthermore, Nano-DESI enables efficient detection of chemically labile compounds in OA, which is important for understanding chemical aging phenomena.

  11. Fire aerosol experiment and comparisons with computer code predictions

    NASA Astrophysics Data System (ADS)

    Gregory, W. S.; Nichols, B. D.; White, B. W.; Smith, P. R.; Leslie, I. H.; Corkran, J. R.

    1988-08-01

    Los Alamos National Laboratory, in cooperation with New Mexico State University, has carried on a series of tests to provide experimental data on fire-generated aerosol transport. These data will be used to verify the aerosol transport capabilities of the FIRAC computer code. FIRAC was developed by Los Alamos for the U.S. Nuclear Regulatory Commission. It is intended to be used by safety analysts to evaluate the effects of hypothetical fires on nuclear plants. One of the most significant aspects of this analysis deals with smoke and radioactive material movement throughout the plant. The tests have been carried out using an industrial furnace that can generate gas temperatures to 300 C. To date, we have used quartz aerosol with a median diameter of about 10 microns as the fire aerosol simulant. We also plan to use fire-generated aerosols of polystyrene and polymethyl methacrylate (PMMA). The test variables include two nominal gas flow rates (150 and 300 cu ft/min) and three nominal gas temperatures (ambient, 150 C, and 300 C). The test results are presented in the form of plots of aerosol deposition vs length of duct. In addition, the mass of aerosol caught in a high-efficiency particulate air (HEPA) filter during the tests is reported. The tests are simulated with the FIRAC code, and the results are compared with the experimental data.

  12. The LNA VPH characterization experiment

    NASA Astrophysics Data System (ADS)

    Ribeiro, Flávio F.; Katime-Santrich, Orlando J.; Gneiding, Clemens D.; Castilho, Bruno V.; Campos, Rodrigo P.; Nicolau, Rogério A.

    2008-07-01

    The use of Volume Phase Holographic (VPH) gratings in astronomy is increasing worldwide due to its high efficiency, flexibility in manufacturing and lower costs. For example 3 of 4 SOAR Telescope spectrographs are based on VPH gratings. Following the growth in this technology use, tools are needed to characterize these gratings for their physical and diffraction efficiency properties. We developed, at Laboratorio Nacional de Astrofisica / MCT (LNA), Brazil, an assembly for characterization of VPH gratings. The relative efficiency of the gratings can be measured for specific angles or scanned through the grating operation angles. Furthermore surface flatness and mounting stress effects are measured using interferometric techniques. We present the experiment design and characteristics, describe the measurement procedures and show the characterization results for some gratings of the SOAR Telescope spectrograph STELES.

  13. Recent Improvements to CALIOP Level 3 Aerosol Profile Product for Global 3-D Aerosol Extinction Characterization

    NASA Astrophysics Data System (ADS)

    Tackett, J. L.; Getzewich, B. J.; Winker, D. M.; Vaughan, M. A.

    2015-12-01

    With nine years of retrievals, the CALIOP level 3 aerosol profile product provides an unprecedented synopsis of aerosol extinction in three dimensions and the potential to quantify changes in aerosol distributions over time. The CALIOP level 3 aerosol profile product, initially released as a beta product in 2011, reports monthly averages of quality-screened aerosol extinction profiles on a uniform latitude/longitude grid for different cloud-cover scenarios, called "sky conditions". This presentation demonstrates improvements to the second version of the product which will be released in September 2015. The largest improvements are the new sky condition definitions which parse the atmosphere into "cloud-free" views accessible to passive remote sensors, "all-sky" views accessible to active remote sensors and "cloudy-sky" views for opaque and transparent clouds which were previously inaccessible to passive remote sensors. Taken together, the new sky conditions comprehensively summarize CALIOP aerosol extinction profiles for a broad range of scientific queries. In addition to dust-only extinction profiles, the new version will include polluted-dust and smoke-only extinction averages. A new method is adopted for averaging dust-only extinction profiles to reduce high biases which exist in the beta version of the level 3 aerosol profile product. This presentation justifies the new averaging methodology and demonstrates vertical profiles of dust and smoke extinction over Africa during the biomass burning season. Another crucial advancement demonstrated in this presentation is a new approach for computing monthly mean aerosol optical depth which removes low biases reported in the beta version - a scenario unique to lidar datasets.

  14. Aerosol Effects on Radiation and Climate: Column Closure Experiments with Towers, Aircraft, and Satellites

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.

    1994-01-01

    Many theoretical studies have shown that anthropogenic aerosol particles can change the radiation balance in an atmospheric column and might thereby exert a significant effect on the Earth's climate. In particular, recent calculations have shown that sulfate particles from anthropogenic combustion may already exert a cooling influence on the Earth that partially offsets the warming caused by the greenhouse gases from the same combustion. Despite the potential climatic importance of anthropogenic aerosols, simultaneous measurements of anthropogenic aerosol properties and their effect on atmospheric radiation have been very rare. Successful comparisons of measured radiation fields with those calculated from aerosol measurements - now referred to as column closure comparisons - are required to improve the accuracy and credibility of climate predictions. This paper reviews the column closure experiment performed at the Mt. Sutro Tower in San Francisco in 1975, in which elevated radiometers measured the change in Earth-plus-atmosphere albedo caused by an aerosol layer, while a lidar, sunphotometer, nephelometer, and other radiometers measured properties of the responsible aerosol. The time-dependent albedo calculated from the measured aerosol properties agreed with that measured by the tower radiometers. Also presented are designs for future column closure studies using radiometers and aerosol instruments on the ground, aircraft, and satellites. These designs draw upon algorithms and experience developed in the Sutro Tower study, as well as more recent experience with current measurement and analysis capabilities.

  15. Remote Sensing of Spectral Aerosol Properties: A Classroom Experience

    NASA Technical Reports Server (NTRS)

    Levy, Robert C.; Pinker, Rachel T.

    2006-01-01

    Bridging the gap between current research and the classroom is a major challenge to today s instructor, especially in the sciences where progress happens quickly. NASA Goddard Space Flight Center and the University of Maryland teamed up in designing a graduate class project intended to provide a hands-on introduction to the physical basis for the retrieval of aerosol properties from state-of-the-art MODIS observations. Students learned to recognize spectral signatures of atmospheric aerosols and to perform spectral inversions. They became acquainted with the operational MODIS aerosol retrieval algorithm over oceans, and methods for its evaluation, including comparisons with groundbased AERONET sun-photometer data.

  16. Characterization of the Sunset Semi-Continuous Carbon Aerosol Analyzer

    SciTech Connect

    Bauer, Jace J.; Yu, Xiao-Ying; Cary, R.; Laulainen, Nels S.; Berkowitz, Carl M.

    2009-07-01

    Accurate quantification of carbonaceous aerosols is essential for reducing uncertainty in climate change models and is important for long-term air quality monitoring by government agencies. The field-deployable Sunset Semi-Continuous Organic Carbon/Elemental Carbon Aerosol Analyzer (Sunset OCEC) utilizes a modified National Institute for Occupational Safety and Health thermal-optical method to determine total carbon (TC), organic carbon (OC), and elemental carbon (EC) at near real-time; however, its performance is not yet fully characterized. Two collocated Sunset OCEC Analyzers, Unit A and Unit B, were used to determine the relative standard deviation (RSD) and limit of detection (LOD) between June 23 and July 9, 2007, in Richland, Washington, USA. A high-efficiency particulate air filter was utilized to determine the LODs of both instruments. The RSDs between the two Sunset OCECs were 9.12% for TC, 13.0% for Optical OC, and 8.97% for Thermal OC, indicating good precision between the instruments, although the RSDs for Thermal and Optical EC were higher, 29.0% and 48.3%, respectively. The LOD of Unit A was approximately 0.21 µgC/m3 for TC, Optical OC, and Thermal OC, and ~0.004 µgC/m3 for Optical and Thermal EC. Similarly, Unit B had an LOD of ~0.29 µgC/m3 for TC, Optical OC, and Thermal OC, 0.018 µgC/m3 for Optical EC, and 0.004 µgC/m3 for Thermal EC. Factors that may have contributed to the poor RSDs of Thermal and Optical EC include the low EC mass loading in Richland, minor leakage in the oxygen valve of Unit B, and excessive noise from the non-dispersive infrared (NDIR) laser in Unit B, resulting in scattered Optical EC measurements. Improved RSDs of all OC and EC parameters are expected after the Unit B NDIR is tuned up. Future work should reevaluate the precision of the Sunset OCECs and investigate the differences in various thermal-optical protocols on OCEC quantification.

  17. Characterization of smoke aerosols over the Indochina Peninsula from multi-platform satellite observations

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Multi-faceted near-simultaneous observations from the sensors aboard multiple satellite platforms, so called the A-Train, are utilized to characterize the spatial distributions and the optical properties of smoke aerosols over the Indochina Peninsula. Observations from the A-Train sensors, especially, MODerate resolution Imaging Spectroradiometer (MODIS), Ozone Monitoring Instrument (OMI), and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), are synthesized to retrieve single-scattering albedo (SSA) and effective aerosol layer height (ALH) of BBS aerosols in the region. The retrieval algorithm extracts the absorption and height information about smoke aerosols, which is lumped into ultraviolet spectra at the top of the atmosphere, by taking the most reliable information contents that each satellite measurement can deliver. The results of retrieved SSA and ALH showed reasonable agreements with in-situ measurements, AEROsol Robotic NETwork (AERONET) data, and lidar-based observations. The uncertainty and sensitivity of the retrieval algorithm are also presented. The retrieved quantities are then used together with other satellite datasets to characterize the three-dimensional distributions of smoke aerosols over the Indochina Peninsular during the boreal spring time. Given the frequent horizontal collocations of smoke and clouds in the region, implication of smoke vertical distributions for long-range transports is also discussed. The results of this study are anticipated to advance our understanding on the climatic impacts of the smoke aerosols in the region.

  18. MODIS and AERONET characterization of the global aerosol

    NASA Astrophysics Data System (ADS)

    Kaufman, Y. J.; Remer, L. A.; Tanre, D.

    2002-05-01

    Recently produced daily MODIS aerosol data for the whole year of 2001 are used to show the concentration and dynamics of aerosol over ocean and large parts of the continents. The data were validated against the Aerosol Robotic Network (AERONET) measurements over land and ocean. Monthly averages and a movie based on the daily data are produced and used to demonstrate the spatial and temporal evolution of aerosol. The MODIS wide spectral range is used to distinguish fine smoke and pollution aerosol from coarse dust and salt. The movie produced from the MODIS data provides a new dimension to aerosol observations by showing the dynamics of the system. For example in February smoke and dust emitted from the Sahel and West Africa is shown to travel to the North-East Atlantic. In April heavy dust and pollution from East Asia is shown to travel to North America. In May-June pollution and dust play a dynamical dance in the Arabian Sea and Bay of Bengal. In Aug-September smoke from South Africa and South America is shown to pulsate in tandem and to periodically to be transported to the otherwise pristine Southern part of the Southern Hemisphere. To use the MODIS data for global assessment of aerosol forcing AERONET data are used to answer some key critical questions: - Are MODIS data collected at 10:30 am representative of the daily forcing? - What is the concentration and properties of background aerosol and that of anthropogenic aerosol These questions and more will be answered in the talk

  19. Aromatic organosulfates in atmospheric aerosols: Synthesis, characterization, and abundance

    NASA Astrophysics Data System (ADS)

    Staudt, Sean; Kundu, Shuvashish; Lehmler, Hans-Joachim; He, Xianran; Cui, Tianqu; Lin, Ying-Hsuan; Kristensen, Kasper; Glasius, Marianne; Zhang, Xiaolu; Weber, Rodney J.; Surratt, Jason D.; Stone, Elizabeth A.

    2014-09-01

    Aromatic organosulfates are identified and quantified in fine particulate matter (PM2.5) from Lahore, Pakistan, Godavari, Nepal, and Pasadena, California. To support detection and quantification, authentic standards of phenyl sulfate, benzyl sulfate, 3- and 4-methylphenyl sulfate and 2-, 3-, and 4-methylbenzyl sulfate were synthesized. Authentic standards and aerosol samples were analyzed by ultra-performance liquid chromatography (UPLC) coupled to negative electrospray ionization (ESI) quadrupole time-of-flight (ToF) mass spectrometry. Benzyl sulfate was present in all three locations at concentrations ranging from 4 to 90 pg m-3. Phenyl sulfate, methylphenyl sulfates and methylbenzyl sulfates were observed intermittently with abundances of 4 pg m-3, 2-31 pg m-3, 109 pg m-3, respectively. Characteristic fragment ions of aromatic organosulfates include the sulfite radical (rad SO3-, m/z 80) and the sulfate radical (rad SO4-, m/z 96). Instrumental response factors of phenyl and benzyl sulfates varied by a factor of 4.3, indicating that structurally-similar organosulfates have significantly different instrumental responses and highlighting the need to develop authentic standards for absolute quantitation organosulfates. In an effort to better understand the sources of aromatic organosulfates to the atmosphere, chamber experiments with the precursor toluene were conducted under conditions that form biogenic organosulfates. Aromatic organosulfates were not detected in the chamber samples, suggesting that they form through different pathways, have different precursors (e.g. naphthalene or methylnaphthalene), or are emitted from primary sources.

  20. Chemical characterizations of soluble aerosols in southern China.

    PubMed

    Wu, Dui; Tie, Xuexi; Deng, Xuejiao

    2006-07-01

    Soluble aerosols are measured at Guangdong and Hainan Provinces of southern China. The measured chemical composition of aerosols includes F-, Cl-, NO3-, SO4=, Na+, NH4+, K+, Ca2+, and Mg2+. The locations of measurements include a mega city (Guangzhou), a medium city along the coastline (Haiko), a small city along the coastline (Shanya), and a remote island site in the South China Sea (Yongxing island). The results reveal that aerosols in this region are complex and heterogeneous. Sulfate aerosol (SO4=) has the highest concentrations in Guangzhou (approximately 41% of total soluble aerosol mass), suggesting that anthropogenic activities (e.g., coal burning) play important roles in controlling aerosol concentrations in Guangzhou. By contrast, the concentrations of chlorine (Cl-) and sodium (Na+) are higher in Yongxing than in Guangzhou, indicating that the sea salt is the dominant aerosol in this marine environment site. In the medium (Haiko) and small (Shanya) city sites, the effects of anthropogenic and marine activities on aerosols fall in between the values in the mega city and the remote island site. The measured ratio of Cl-/Na+ shows that the ratio is less than 1.16 in all observation sites. The ratio in the Guangzhou city, the Haiko city, the Shanya city, and the Yongxing island is 0.52, 0.91, 0.24, and 0.53, respectively, indicating that significantly heterogeneous chemical reactions occur on sea salt particles. Unlike those in Europe and North America, there are high concentrations of calcium (Ca+) in all observation sites. The percentage of calcium mass to the measured total soluble aerosols mass is 21, 32, 34, and 30 at Guangzhou, Haiko, Sanya, and Yongxing, respectively. The calculations show that calcium plays an important role in neutralizing aerosols. The calculated "cation/anion" (summation operator[ion+]/summation operator[ion-]) ratio is 2.5, 2.5, 3.2, and 2.1, at Guangzhou, Haiko, Shanya, and Yongxing, respectively. The high "cation/anion" ratios

  1. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; di Sarra, A.; Alados, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Brogniez, G.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Denjean, C.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, J.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Wenger, J.; Zapf, P.

    2015-07-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Forcing on the Mediterranean Climate (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental set-up also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modelling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to produce high level of atmospheric pollutants nor

  2. An Overview of Regional Experiments on Biomass Burning Aerosols and Related Pollutants in Southeast Asia: From BASE-ASIA and the Dongsha Experiment to 7-SEAS

    NASA Technical Reports Server (NTRS)

    Lin, Neng-Huei; Tsay, Si-Chee; Maring, Hal B.; Yen, Ming-Cheng; Sheu, Guey-Rong; Wang, Sheng-Hsiang; Chi, Kai Hsien; Chuang, Ming-Tung; Ou-Yang, Chang-Feng; Fu, Joshua S.; Reid, Jeffrey S.; Lee, Chung-Te; Wang, Lin-Chi; Wang, Jia-Lin; Hsu, Christina N.; Sayer, Andrew M.; Holben, Brent N.; Chu, Yu-Chi; Nguyen, Xuan Anh; Sopajaree, Khajornsak; Chen, Shui-Jen; Cheng, Man-Ting; Tsuang, Ben-Jei; Tsai, Chuen-Jinn; Peng, Chi-Ming; Schnell, Russell C.; Conway, Tom; Chang, Chang-Tang; Lin, Kuen-Song; Tsai, Ying I.; Lee, Wen-Jhy; Chang, Shuenn-Chin; Liu, Jyh-Jian; Chang, Wei-Li; Huang, Shih-Jen; Lin, Tang-Huang; Liu, Gin-Rong

    2013-01-01

    By modulating the Earth-atmosphere energy, hydrological and biogeochemical cycles, and affecting regional-to-global weather and climate, biomass burning is recognized as one of the major factors affecting the global carbon cycle. However, few comprehensive and wide-ranging experiments have been conducted to characterize biomass-burning pollutants in Southeast Asia (SEA) or assess their regional impact on meteorology, the hydrological cycle, the radiative budget, or climate change. Recently, BASEASIA (Biomass-burning Aerosols in South-East Asia: Smoke Impact Assessment) and the 7-SEAS (7- South-East Asian Studies) Dongsha Experiment were conducted during the spring seasons of 2006 and 2010 in northern SEA, respectively, to characterize the chemical, physical, and radiative properties of biomass-burning emissions near the source regions, and assess their effects. This paper provides an overview of results from these two campaigns and related studies collected in this special issue, entitled Observation, modeling and impact studies of biomass burning and pollution in the SE Asian Environment. This volume includes 28 papers, which provide a synopsis of the experiments, regional weatherclimate, chemical characterization of biomass-burning aerosols and related pollutants in source and sink regions, the spatial distribution of air toxics (atmospheric mercury and dioxins) in source and remote areas, a characterization of aerosol physical, optical, and radiative properties, as well as modeling and impact studies. These studies, taken together, provide the first relatively complete dataset of aerosol chemistry and physical observations conducted in the sourcesink region in the northern SEA, with particular emphasis on the marine boundary layer and lower free troposphere (LFT). The data, analysis and modeling included in these papers advance our present knowledge of source characterization of biomass-burning pollutants near the source regions as well as the physical and

  3. 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

    Herein is reported activities to support the characterization of the aerosol in the upper troposphere (UT) and lower stratosphere (LS) collected during the Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft (ASHOE/MAESA) missions in 1994. Through a companion proposal, another group was to measure the size distribution of aerosols in the 0.008 to 2 micrometer diameter range and to collect for us impactor samples of particles larger than about 0.02 gm. In the first year, we conducted laboratory studies related to particulate deposition patterns on our collection substrates, and have performed the analysis of many ASHOE/MAESA aerosol samples from 1994 using analytical electron microscopy (AEM). We have been building an "aerosol climatology" with these data that documents the types and relative abundances of particles observed at different latitudes and altitudes. The second year (and non-funded extension periods) saw continued analyses of impactor aerosol samples, including more ASHOE/MAESA samples, some northern hemisphere samples from the NASA Stratospheric Photochemistry Aerosols and Dynamics Expedition (SPADE) program for comparison, and a few aerosol samples from the NASA Stratospheric TRacers of Atmospheric Transport (STRAT) program. A high-resolution field emission microscope was used for the analysis and re-analysis of a number of samples to determine if this instrument was superior in performance to our conventional electron microscope. In addition, some basic laboratory studies were conducted to determine the minimum detectable and analyzable particle size for different types of aerosols. In all, 61 aerosol samples were analyzed, with a total of over 30,000 individual particle analyses. In all analyzed samples, sulfate particles comprised the major aerosol number fraction. It must be stressed that particles composed of more than one species, for example sulfate and organic carbon, were classified

  4. Tropospheric ozone and aerosols measured by airborne lidar during the 1988 Arctic boundary layer experiment

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Ozone (O3) and aerosol distributions were measured from an aircraft using a differential absorption lidar (DIAL) system as part of the 1988 NASA Global Tropospheric Experiment - Arctic Boundary Layer Experiment (ABLE-3A) to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during the summer. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere. Several cases of continental polar air masses were examined during the experiment. The aerosol scattering associated with these air masses was very low, and the atmospheric distribution of aerosols was quite homogeneous for those air masses that had been transported over the ice for greater than or = 3 days. The transition in O3 and aerosol distributions from tundra to marine conditions was examined several times. The aerosol data clearly show an abrupt change in aerosol scattering properties within the mixed layer from lower values over the tundra to generally higher values over the water. The distinct differences in the heights of the mixed layers in the two regions was also readily apparent. Several cases of enhanced O3 were observed during ABLE-3 in conjunction with enhanced aerosol scattering in layers in the free atmosphere. Examples are presented of the large scale variations of O3 and aerosols observed with the airborne lidar system from near the surface to above the tropopause over the Arctic during ABLE-3.

  5. Thermodynamic Characterization of Mexico City Aerosol during MILAGRO 2006

    SciTech Connect

    Fountoukis, C.; Nenes, A.; Sullivan, A.; Weber, R.; VanReken, T.; Fischer, M.; Matias, E.; Moya, M.; Farmer, D.; Cohen, R.C.

    2008-12-05

    Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM{sub 2.5} is insensitive to changes in ammonia but is to acidic semivolatile species. For particle sizes up to 1 {micro}m diameter, semi-volatile partitioning requires 30-60 min to equilibrate; longer time is typically required during the night and early morning hours. When the aerosol sulfate-to-nitrate molar ratio is less than unity, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as 'equivalent sodium' (rather than explicitly) in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatically. This suggests that explicitly considering crustals in the thermodynamic calculations is required to accurately predict the partitioning and phase state of aerosols.

  6. MODIS and AERONET Characterization of the Global Aerosol

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram; Reme, Lorraine; Tanre, Didier; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Recently produced daily MODIS aerosol data for the whole year of 2001 are used to show the concentration and dynamics of aerosol over ocean and large parts of the continents. The data were validated against the Aerosol Robotic Network (AERONET) measurements over land and ocean. Monthly averages and a movie based on the daily data are produced and used to demonstrate the spatial and temporal evolution of aerosol. The MODIS wide spectral range is used to distinguish fine smoke and pollution aerosol from coarse dust and salt. The movie produced from the MODIS data provides a new dimension to aerosol observations by showing the dynamics of the system. For example in February smoke and dust emitted from the Sahel and West Africa is shown to travel to the North-East Atlantic. In April heavy dust and pollution from East Asia is shown to travel to North America. In May-June pollution and dust play a dynamical dance in the Arabian Sea and Bay of Bengal. In Aug-September smoke from South Africa and South America is shown to pulsate in tandem and to periodically to be transported to the otherwise pristine Southern part of the Southern Hemisphere.

  7. 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.

  8. Characterization of intense aerosol episodes in the Mediterranean basin from satellite observations

    NASA Astrophysics Data System (ADS)

    Gkikas, Antonis; Hatzianastassiou, Nikos; Mihalopoulos, Nikolaos

    2014-05-01

    The properties and distribution of aerosols over the broader Mediterranean region are complex since particles of different nature are either produced within its boundaries or transported from other regions. Thus, coarse dust aerosols are transported primarily from Sahara and secondarily from Middle East, while fine polluted aerosols are either produced locally from anthropogenic activities or they are transported from neighbouring or remote European areas. Also during summer biomass aerosols are transported towards the Mediterranean, originating from massive and extended fires occurring in northern Balkans and Eastern Europe and favoured by the prevailing synoptic conditions. In addition, sea-salt aerosols originate from the Mediterranean Sea or the Atlantic Ocean. Occasionally, aerosols are encountered at very high concentrations (aerosol episodes or events) significantly affecting atmospheric dynamics and climate as well as human health. Given the coexistence of different aerosols as internal and external mixtures characterizing and discriminating between the different types of aerosol episodes is a big challenge. A characterization and classification of intense aerosol episodes in the Mediterranean basin (March 2000 - February 2007) is attempted in the present study. This is achieved by implementing an objective and dynamic algorithm which uses daily aerosol optical properties derived from satellite measurements, namely MODIS-Terra, Earth Probe (EP)-TOMS and OMI-Aura. The aerosol episodes are first classified into strong and extreme ones, according to their intensity, by means of aerosol optical depth at 550nm (AOD550nm). Subsequently, they are discriminated into the following aerosol types: (i) biomass/urban-industrial (BU), (ii) desert dust (DD), (iii) sea-salt like (SS), (iv) mixed (MX) and (v) undetermined (UN). The classification is based on aerosol optical properties accounting for the particles' size (Ångström exponent, Effective radius), the

  9. Characterizing the Hygroscopicity of Nascent Sea Spray Aerosol from Synthetic Blooms

    NASA Astrophysics Data System (ADS)

    Forestieri, S.; Cappa, C. D.; Sultana, C. M.; Lee, C.; Wang, X.; Helgestad, T.; Moore, K.; Prather, K. A.; Cornwell, G.; Novak, G.; Bertram, T. H.

    2015-12-01

    Marine sea spray aerosol (SSA) particles make up a significant portion of natural aerosols and are therefore important in establishing the baseline for anthropogenic aerosol climate impacts. Scattering of solar radiation by aerosols affects Earth's radiative budget and the degree of scattering is size-dependent. Thus, aerosols scatter more light at elevated relative humidities when they grow larger via water uptake. This growth depends critically on chemical composition. SSA can become enriched in organics during phytoplankton blooms, becoming less salty and therefore less hygroscopic. Subsaturated hygroscopic growth factors at 85% relative humidity (GF(85%)) of SSA particles were quantified during two mesocosm experiments in enclosed marine aerosol reference tanks (MARTs). The two experiments were conducted with filtered seawater collected at separate times from the Scripps Institute of Oceanography Pier in La Jolla, CA. Phytoplankton blooms in each tank were induced via the addition of nutrients and photosynthetically active radiation. The "indoor" MART was illuminated with fluorescent light and the other "outdoor" MART was illuminated with sunlight. The peak chlorophyll-a concentrations were 59 micrograms/L and 341 micrograms /L for the indoor and outdoor MARTs, respectively. GF(85%) values for SSA particles were quantified using a humidified cavity ringdown spectrometer and particle size distributions. Particle composition was monitored with a single particle aerosol mass spectrometer (ATOFMS) and an Aerodyne aerosol mass spectrometer (AMS). Relationships between the observed particle GFs and the particle composition markers will be discussed.

  10. Characterization of ambient aerosols at the San Francisco International Airport using BioAerosol Mass Spectrometry

    SciTech Connect

    Steele, P T; McJimpsey, E L; Coffee, K R; Fergenson, D P; Riot, V J; Tobias, H J; Woods, B W; Gard, E E; Frank, M

    2006-03-16

    The BioAerosol Mass Spectrometry (BAMS) system is a rapidly fieldable, fully autonomous instrument that can perform correlated measurements of multiple orthogonal properties of individual aerosol particles. The BAMS front end uses optical techniques to nondestructively measure a particle's aerodynamic diameter and fluorescence properties. Fluorescence can be excited at 266nm or 355nm and is detected in two broad wavelength bands. Individual particles with appropriate size and fluorescence properties can then be analyzed more thoroughly in a dual-polarity time-of-flight mass spectrometer. Over the course of two deployments to the San Francisco International Airport, more than 6.5 million individual aerosol particles were fully analyzed by the system. Analysis of the resulting data has provided a number of important insights relevant to rapid bioaerosol detection, which are described here.

  11. Characterizing interactions between aerosols and cloud droplets in marine boundary layer clouds

    NASA Astrophysics Data System (ADS)

    Andersen, Hendrik; Cermak, Jan

    2016-04-01

    This contribution presents a method to characterize the nonlinearities of interactions between aerosols and cloud droplets in marine boundary layer clouds based on global MODIS observations. Clouds play a crucial role in the climate system as their radiative properties and precipitation patterns significantly impact the Earth's energy balance. Cloud properties are determined by environmental conditions, as cloud formation requires the availability of water vapour ("precipitable water") and condensation nuclei in sufficiently saturated conditions. The ways in which aerosols as condensation nuclei in particular influence the optical, micro- and macrophysical properties of clouds are one of the largest remaining uncertainties in climate-change research. In particular, cloud droplet size is believed to be impacted, and thereby cloud reflectivity, lifetime, and precipitation susceptibility. However, the connection between aerosols and cloud droplets is nonlinear, due to various factors and processes. The impact of aerosols on cloud properties is thought to be strongest with low aerosol loadings, whereas it saturates with high aerosol loadings. To gain understanding of the processes that govern low cloud water properties in order to increase accuracy of climate models and predictions of future changes in the climate system is thus of great importance. In this study, global Terra MODIS L3 data sets are used to characterize the nonlinearities of the interactions between aerosols and cloud droplets in marine boundary layer clouds. MODIS observations are binned in classes of aerosol loading to identify at what loading aerosol impact on cloud droplets is the strongest and at which loading it saturates. Results are connected to ERA-Interim and MACC data sets to identify connections of detected patterns to meteorology and aerosol species.

  12. Atmospheric aerosol characterization combining multi-wavelength Raman lidar and MAX-DOAS measurements in Gwanjgu

    NASA Astrophysics Data System (ADS)

    Chong, Jihyo; Shin, Dong Ho; Kim, Kwang Chul; Lee, Kwon-Ho; Shin, Sungkyun; Noh, Young M.; Müller, Detlef; Kim, Young J.

    2011-11-01

    Integrated approach has been adopted at the ADvanced Environmental Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosol. Various active and passive optical remote sensing techniques such as multi-wavelength (3β+2α+1δ) Raman LIDAR, sun-photometry, MAX-DOAS, and satellite retrieval have been utilized. This integrated monitoring system approach combined with in-situ surface measurement is to allow better characterization of physical and optical properties of atmospheric aerosol. Information on the vertical distribution and microphysical properties of atmospheric aerosol is important for understanding its transport characteristics as well as radiative effect. The GIST multi-wavelength (3β + 2α+1δ) Raman lidar system can measure vertical profiles of optical properties of atmospheric aerosols such as extinction coefficients at 355 and 532nm, particle backscatter coefficients at 355, 532 and 1064 nm, and depolarization ratio at 532nm. The incomplete overlap between the telescope field-of-view and beam divergence of the transmitting laser significantly affects lidar measurement, resulting in higher uncertainty near the surface where atmospheric aerosols of interest are concentrated. Differential Optical Absorption Spectroscopy (DOAS) technique is applied as a complementary tool for the detection of atmospheric aerosols near the surface. The passive Multi-Axis DOAS (MAX-DOAS) technique uses scattered sunlight as a light source from several viewing directions. Recently developed aerosol retrieval algorithm based on O4 slant column densities (SCDs) measured at UV and visible wavelengths has been utilized to derive aerosol information (e.g., aerosol optical depth (AOD) and aerosol extinction coefficients (AECs)) in the lower troposphere. The aerosol extinction coefficient at 356 nm was retrieved for the 0-1 and 1-2 km layers based on the MAX-DOAS measurements using the retrieval algorithm

  13. Aromatic organosulfates in atmospheric aerosols: synthesis, characterization, and abundance

    PubMed Central

    Staudt, Sean; Kundu, Shuvashish; Lehmler, Hans-Joachim; He, Xianran; Cui, Tianqu; Lin, Ying-Hsuan; Kristensen, Kasper; Glasius, Marianne; Zhang, Xiaolu; Weber, Rodney J.; Surratt, Jason D.; Stone1, Elizabeth A.

    2014-01-01

    Aromatic organosulfates are identified and quantified in fine particulate matter (PM2.5) from Lahore, Pakistan, Godavari, Nepal, and Pasadena, California. To support detection and quantification, authentic standards of phenyl sulfate, benzyl sulfate, 3-and 4-methylphenyl sulfate and 2-, 3-, and 4-methylbenzyl sulfate were synthesized. Authentic standards and aerosol samples were analyzed by ultra-performance liquid chromatography (UPLC) coupled to negative electrospray ionization (ESI) quadrupole time-of-flight (ToF) mass spectrometry. Benzyl sulfate was present in all three locations at concentrations ranging from 4 – 90 pg m−3. Phenyl sulfate, methylphenyl sulfates and methylbenzyl sulfates were observed intermittently with abundances of 4 pg m−3, 2-31 pg m−3, 109 pg m−3, respectively. Characteristic fragment ions of aromatic organosulfates include the sulfite radical (•SO3−, m/z 80) and the sulfate radical (•SO4−,m/z 96). Instrumental response factors of phenyl and benzyl sulfates varied by a factor of 4.3, indicating that structurally-similar organosulfates may have significantly different instrumental responses and highlighting the need to develop authentic standards for absolute quantitation organosulfates. In an effort to better understand the sources of aromatic organosulfates to the atmosphere, chamber experiments with the precursor toluene were conducted under conditions that form biogenic organosulfates. Aromatic organosulfates were not detected in the chamber samples, suggesting that they form through different pathways, have different precursors (e.g. naphthalene or methylnaphthalene), or are emitted from primary sources. PMID:24976783

  14. Characterization of aerosols containing Legionella generated upon nebulization

    NASA Astrophysics Data System (ADS)

    Allegra, Séverine; Leclerc, Lara; Massard, Pierre André; Girardot, Françoise; Riffard, Serge; Pourchez, Jérémie

    2016-09-01

    Legionella pneumophila is, by far, the species most frequently associated with Legionnaires’ disease (LD). Human infection occurs almost exclusively by aerosol inhalation which places the bacteria in juxtaposition with alveolar macrophages. LD risk management is based on controlling water quality by applying standardized procedures. However, to gain a better understanding of the real risk of exposure, there is a need (i) to investigate under which conditions Legionella may be aerosolized and (ii) to quantify bacterial deposition into the respiratory tract upon nebulization. In this study, we used an original experimental set-up that enables the generation of aerosol particles containing L. pneumophila under various conditions. Using flow cytometry in combination with qPCR and culture, we determined (i) the size of the aerosols and (ii) the concentration of viable Legionella forms that may reach the thoracic region. We determined that the 0.26–2.5 μm aerosol size range represents 7% of initial bacterial suspension. Among the viable forms, 0.7% of initial viable bacterial suspension may reach the pulmonary alveoli. In conclusion, these deposition profiles can be used to standardize the size of inoculum injected in any type of respiratory tract model to obtain new insights into the dose response for LD.

  15. Characterization of aerosols containing Legionella generated upon nebulization

    PubMed Central

    Allegra, Séverine; Leclerc, Lara; Massard, Pierre André; Girardot, Françoise; Riffard, Serge; Pourchez, Jérémie

    2016-01-01

    Legionella pneumophila is, by far, the species most frequently associated with Legionnaires’ disease (LD). Human infection occurs almost exclusively by aerosol inhalation which places the bacteria in juxtaposition with alveolar macrophages. LD risk management is based on controlling water quality by applying standardized procedures. However, to gain a better understanding of the real risk of exposure, there is a need (i) to investigate under which conditions Legionella may be aerosolized and (ii) to quantify bacterial deposition into the respiratory tract upon nebulization. In this study, we used an original experimental set-up that enables the generation of aerosol particles containing L. pneumophila under various conditions. Using flow cytometry in combination with qPCR and culture, we determined (i) the size of the aerosols and (ii) the concentration of viable Legionella forms that may reach the thoracic region. We determined that the 0.26–2.5 μm aerosol size range represents 7% of initial bacterial suspension. Among the viable forms, 0.7% of initial viable bacterial suspension may reach the pulmonary alveoli. In conclusion, these deposition profiles can be used to standardize the size of inoculum injected in any type of respiratory tract model to obtain new insights into the dose response for LD. PMID:27671446

  16. Characterization of aerosol composition, concentrations, and sources at Baengnyeong Island, Korea using an aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Lee, Taehyoung; Choi, Jinsoo; Lee, Gangwoong; Ahn, Junyoung; Park, Jin Soo; Atwood, Samuel A.; Schurman, Misha; Choi, Yongjoo; Chung, Yoomi; Collett, Jeffrey L.

    2015-11-01

    To improve understanding of the sources and chemical properties of particulate pollutants on the western side of the Korean Peninsula, an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) measured non-refractory fine (PM1) particles from May to November, 2011 at Baengnyeong Island, South Korea. Organic matter and sulfate were generally the most abundant species and exhibited maximum concentrations of 36 μg/m3 and 39 μg/m3, respectively. Nitrate concentrations peaked at 32 μg/m3 but were typically much lower than sulfate and organic matter concentrations. May, September, October, and November featured the highest monthly average concentrations, with lower concentrations typically observed from June through August. Potential source contribution function (PSCF) analysis and individual case studies revealed that transport from eastern China, an area with high SO2 emissions, was associated with high particulate sulfate concentrations at the measurement site. Observed sulfate aerosol sometimes was fully neutralized by ammonium but often was acidic; the average ammonium to sulfate molar ratio was 1.49. Measured species size distributions revealed a range of sulfate particle size distributions with modes between 100 and 600 nm. Organic aerosol source regions were widespread, including contributions from eastern China and South Korea. Positive matrix factorization (PMF) analysis indicated three "factors," or types of organic aerosol, comprising one primary, hydrocarbon-like organic aerosol (HOA) and two oxidized organic aerosol (OOA) components, including a more oxidized (MO-OOA) and a less oxidized (LO-OOA) oxidized organic aerosol. On average, HOA and OOA contributed 21% and 79% of the organic mass (OM), respectively, with the MO-OOA fraction nearly three times as abundant as the LO-OOA fraction. Biomass burning contributions to observed OM were low during the late spring/early summer agricultural burning season in eastern China, since

  17. Formation and characterization of fission-product aerosols under postulated HTGR accident conditions

    SciTech Connect

    Tang, I.N.; Munkelwitz, H.R.

    1982-07-01

    The paper presents the results of an experimental investigation on the formation mechanism and physical characterization of simulated nuclear aerosols that could likely be released during an HTGR core heat-up accident. Experiments were carried out in a high-temperature flow system consisting essentially of an inductively heated release source, a vapor deposition tube, and a filter assembly for collecting particulate matter. Simulated fission products Sr and Ba as oxides are separately impregnated in H451 graphite wafers and released at elevated temperatures into a dry helium flow. In the presence of graphite, the oxides are quantitatively reduced to metals, which subsequently vaporize at temperatures much lower than required for the oxides alone to vaporize in the absence of graphite. A substantial fraction of the released material is associated with particulate matter, which is collected on filters located downstream at ambient temperature. The release and transport of simulated fission product Ag as metal are also investigated.

  18. Characterization of Red Tide Aerosol on the Texas Coast.

    PubMed

    Cheng, Yung Sung; Villareal, Tracy A; Zhou, Yue; Gao, Jun; Pierce, Richard; Naar, Jerome; Baden, Daniel G

    2005-01-01

    The Gulf of Mexico red tide, caused by the dinoflagellate Karenia brevis (= Gymnodinium breve), occurs almost annually and has adverse economic and health effects. Exposure of people to sea spray containing aerosolized brevetoxins (PbTxs, polyether brevetoxins produced by K. brevis) causes irritation of the eyes, nose, and throat. Anecdotal reports suggest that exposed individuals can experience respiratory irritation and exacerbation of existing respiratory illnesses. There has been no systematic study of human exposure to red tide aerosols. In the fall of 2000, during a red tide episode on the Gulf Coast near Corpus Christi, Texas, we sampled at the Marine Science Institute (MSI) at Port Aransas on 25 October. Between 26-27 October we sampled at the Texas State Aquarium (TSA) near Corpus Christi. Two Hi-Vol samplers equipped with a filter and a five-stage impactor gave low concentrations of PbTxs, requiring us to develop methods to improve the minimum detection limit. An LC/MS/MS technique was used combining an HPLC and the API 365 MS/MS. PbTx-2 and PbTx-3 were detected at the TSA sampling location; however, PbTx was not detected in the samples from the MSI. The concentration of PbTx-2 was 1.5-4.9 ng m(-3) but was much lower for PbTx-3. The ratio of PbTx-2 to PbTx-3 was 8.7 +/- 5.2. During the highest exposure period (26-27 October), PbTx-6 was also detected. No one reported respiratory symptoms at the MSI, whereas at the TSA, several field study workers reported symptoms including nose and throat irritation, and itchy skin. A high-volume impactor was used to aerodynamically classify the particles into different size fractions. PbTx-2 was detected in all samples taken at the TSA; however, PbTx-3 was detected only between 26-27 October when the PbTx concentration was high. The mass median aerodynamic diameter (MMAD) was 7-9 mm with a relatively narrow size range (geometric standard deviation [GSD] about 1.6). In this study, much lower airborne concentrations of Pb

  19. Characterization of the Aerosol Instrument Package for the In-service Aircraft Global Observing System IAGOS

    NASA Astrophysics Data System (ADS)

    Bundke, Ulrich; Berg, Marcel; Tettig, Frank; Franke, Harald; Petzold, Andreas

    2015-04-01

    The atmospheric aerosol influences the climate twofold via the direct interaction with solar radiation and indirectly effecting microphysical properties of clouds. The latter has the largest uncertainty according to the last IPPC Report. A measured in situ climatology of the aerosol microphysical properties is needed to reduce the reported uncertainty of the aerosol climate impact. The European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System; www.iagos.org) responds to the increasing requests for long-term, routine in situ observational data by using commercial passenger aircraft as measurement platform. However, scientific instrumentation for the measurement of atmospheric constituents requires major modifications before being deployable aboard in-service passenger aircraft. The IAGOS Aerosol Package (IAGOS-P2C) consists of two modified Butanol based CPCs (Model Grimm 5.410) and one optical particle counter (Model Grimm Sky OPC 1.129). A thermodenuder at 250°C is placed upstream the second CPC, thus the number concentrations of the total aerosol and the non-volatile aerosol fraction is measured. The Sky OPC measures the size distribution in the rage theoretically up to 32 μ m. Because of the inlet cut off diameter of D50=3 μ m we are using the 16 channel mode in the range of 250 nm - 2.5 μ m at 1 Hz resolution. In this presentation the IAGOS Aerosol package is characterized for pressure levels relevant for the planned application, down to cruising level of 150 hPa including the inlet system. In our aerosol lab we have tested the system against standard instrumentation with different aerosol test substances in a long duration test. Particle losses are characterized for the inlet system. In addition first results for airborne measurements are shown from a first field campaign.

  20. Profile and Morphology of Fungal Aerosols Characterized by Field Emission Scanning Electron Microscopy (FESEM)

    PubMed Central

    Afanou, Komlavi Anani; Straumfors, Anne; Skogstad, Asbjørn; Skaar, Ida; Hjeljord, Linda; Skare, Øivind; Green, Brett James; Tronsmo, Arne; Eduard, Wijnand

    2016-01-01

    Fungal aerosols consist of spores and fragments with diverse array of morphologies; however, the size, shape, and origin of the constituents require further characterization. In this study, we characterize the profile of aerosols generated from Aspergillus fumigatus, A. versicolor, and Penicillium chrysogenum grown for 8 weeks on gypsum boards. Fungal particles were aerosolized at 12 and 20 L min−1 using the Fungal Spore Source Strength Tester (FSSST) and the Stami particle generator (SPG). Collected particles were analyzed with field emission scanning electron microscopy (FESEM). We observed spore particle fraction consisting of single spores and spore aggregates in four size categories, and a fragment fraction that contained submicronic fragments and three size categories of larger fragments. Single spores dominated the aerosols from A. fumigatus (median: 53%), while the submicronic fragment fraction was the highest in the aerosols collected from A. versicolor (median: 34%) and P. chrysogenum (median: 31%). Morphological characteristics showed near spherical particles that were only single spores, oblong particles that comprise some spore aggregates and fragments (<3.5 μm), and fiber-like particles that regroup chained spore aggregates and fragments (>3.5 μm). Further, the near spherical particles dominated the aerosols from A. fumigatus (median: 53%), while oblong particles were dominant in the aerosols from A. versicolor (68%) and P. chrysogenum (55%). Fiber-like particles represented 21% and 24% of the aerosols from A. versicolor and P. chrysogenum, respectively. This study shows that fungal particles of various size, shape, and origin are aerosolized, and supports the need to include a broader range of particle types in fungal exposure assessment. PMID:26855468

  1. Combined X-Ray and Raman Spectroscopic Techniques for the Characterization of Sea Spray Aerosol

    NASA Astrophysics Data System (ADS)

    Aller, J. Y.; Alpert, P. A.; Knopf, D. A.; Kilthau, W.; Bothe, D.; Charnawskas, J. C.; Gilles, M. K.; OBrien, R. E.; Moffet, R.; Radway, J.

    2014-12-01

    Sea spray aerosol along with mineral dust dominates the global mass flux of particles to the atmosphere. Marine aerosol particles are of particular interest because of their continual impact on cloud formation, precipitation, atmospheric chemical processes, and thus global climate. Here we report on the physical/chemical characteristics of sub-surface waters, aerosolized sea spray particles, and particles/organic species present in surface microlayer (SML) samples collected during oceanic field campaigns and generated during laboratory experiments, revealing a biogenic primary source of the organic fraction of airborne particles. We also report on ice nucleation experiments with aerosolized particles collected during the May 2014 WACS II North Atlantic cruise and with laboratory generated exudate material from diatom cultures with the potential to impact cirrus and mixed phase clouds. Physicochemical analyses using a multi-modal approach which includes Scanning Transmission X-ray Microscopy coupled with Near-Edge Absorption Fine Structure Spectroscopy (STXM/NEXAFS) and Raman spectroscopy confirm the presence and chemical similarity of polysaccharide-rich transparent exopolymer (TEP) material and proteins in both SML sea spray aerosol and ice forming aerosol particles, regardless of the extent of biological activity in surface waters. Our results demonstrate a direct relationship between the marine environment and composition of marine aerosol through primary particle emission.

  2. Real-Time Characterization of Aerosol Particle Composition above the Urban Canopy in Beijing: Insights into the Interactions between the Atmospheric Boundary Layer and Aerosol Chemistry.

    PubMed

    Sun, Yele; Du, Wei; Wang, Qingqing; Zhang, Qi; Chen, Chen; Chen, Yong; Chen, Zhenyi; Fu, Pingqing; Wang, Zifa; Gao, Zhiqiu; Worsnop, Douglas R

    2015-10-01

    Despite extensive efforts into the characterization of air pollution during the past decade, real-time characterization of aerosol particle composition above the urban canopy in the megacity Beijing has never been performed to date. Here we conducted the first simultaneous real-time measurements of aerosol composition at two different heights at the same location in urban Beijing from December 19, 2013 to January 2, 2014. The nonrefractory submicron aerosol (NR-PM1) species were measured in situ by a high-resolution aerosol mass spectrometer at near-ground level and an aerosol chemical speciation monitor at 260 m on a 325 m meteorological tower in Beijing. Secondary aerosol showed similar temporal variations between ground level and 260 m, whereas much weaker correlations were found for the primary aerosol. The diurnal evolution of the ratios and correlations of aerosol species between 260 m and the ground level further illustrated a complex interaction between vertical mixing processes and local source emissions on aerosol chemistry in the atmospheric boundary layer. As a result, the aerosol compositions at the two heights were substantially different. Organic aerosol (OA), mainly composed of primary OA (62%), at the ground level showed a higher contribution to NR-PM1 (65%) than at 260 m (54%), whereas a higher concentration and contribution (15%) of nitrate was observed at 260 m, probably due to the favorable gas-particle partitioning under lower temperature conditions. In addition, two different boundary layer structures were observed, each interacting differently with the evolution processes of aerosol chemistry.

  3. Real-Time Characterization of Aerosol Particle Composition above the Urban Canopy in Beijing: Insights into the Interactions between the Atmospheric Boundary Layer and Aerosol Chemistry.

    PubMed

    Sun, Yele; Du, Wei; Wang, Qingqing; Zhang, Qi; Chen, Chen; Chen, Yong; Chen, Zhenyi; Fu, Pingqing; Wang, Zifa; Gao, Zhiqiu; Worsnop, Douglas R

    2015-10-01

    Despite extensive efforts into the characterization of air pollution during the past decade, real-time characterization of aerosol particle composition above the urban canopy in the megacity Beijing has never been performed to date. Here we conducted the first simultaneous real-time measurements of aerosol composition at two different heights at the same location in urban Beijing from December 19, 2013 to January 2, 2014. The nonrefractory submicron aerosol (NR-PM1) species were measured in situ by a high-resolution aerosol mass spectrometer at near-ground level and an aerosol chemical speciation monitor at 260 m on a 325 m meteorological tower in Beijing. Secondary aerosol showed similar temporal variations between ground level and 260 m, whereas much weaker correlations were found for the primary aerosol. The diurnal evolution of the ratios and correlations of aerosol species between 260 m and the ground level further illustrated a complex interaction between vertical mixing processes and local source emissions on aerosol chemistry in the atmospheric boundary layer. As a result, the aerosol compositions at the two heights were substantially different. Organic aerosol (OA), mainly composed of primary OA (62%), at the ground level showed a higher contribution to NR-PM1 (65%) than at 260 m (54%), whereas a higher concentration and contribution (15%) of nitrate was observed at 260 m, probably due to the favorable gas-particle partitioning under lower temperature conditions. In addition, two different boundary layer structures were observed, each interacting differently with the evolution processes of aerosol chemistry. PMID:26348650

  4. Overview of Asian Biomass Burning and Dust Aerosols Measured during the Dongsha Experiment in the Spring of 2010

    NASA Astrophysics Data System (ADS)

    Lin, N.; Tsay, S.; Wang, S.; Sheu, G.; Chi, K.; Lee, C.; Wang, J.

    2010-12-01

    The international campaign of Dongsha Experiment was conducted in the northern SE Asian region during March-May 2010. It is a pre-study of the Seven South East Asian Studies (7SEAS) which seeks to perform interdisciplinary research in the field of aerosol-meteorology and climate interaction in the Southeast Asian region, particularly for the impact of biomass burning on cloud, atmospheric radiation, hydrological cycle, and regional climate. Participating countries include Indonesia, Malaysia, Philippines, Singapore, Thailand, Taiwan, Vietnam, and USA (NASA, NRL, and NOAA). The main goals of Dongsha Experiment are (1) to develop the Dongsha Island (about 2 km2, 20°42'52" N, 116°43'51" E) in the South China Sea as an atmospheric observing platform of atmospheric chemistry, radiation and meteorological parameters, and (2) to characterize the chemical and physical properties of biomass burning aerosols in the northern SE Asian region. A monitoring network for ground-based measurements includes the Lulin Atmospheric Background Station (2,862 m MSL) in central Taiwan, Hen-Chun (coastal) in the very southern tip of Taiwan, Dongsha Island in South China Sea, Da Nang (near coastal region) in central Vietnam, and Chiang Mai (about 1,400 m, MSL) in northern Thailand. Besides, the Mobile Air Quality Station of Taiwan EPA and NASA/COMMIT were shipped to Dongsha Island for continuous measurements of CO, SO2, NOx, O3, and PM10, and aerosol optical and vertical profiles. Two Intensive Observation Periods (IOPs) for aerosol chemistry were conducted during 14-30 March and 10-20 April 2010, respectively. Ten aerosol samplers were deployed for each station for characterizing the compositions of PM2.5/PM10 (some for TSP) including water-soluble ions, metal elements, BC/OC, Hg and dioxins. Sampling tubes of VOCs were also deployed. Concurrent measurements with IOP-1, Taiwanese R/V also made a mission to South China Sea during 14-19 March. Enhanced sounding at Dongsha Island was

  5. Characterization of Organic Nitrogen in the Atmosphere Using High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ge, X.; Sun, Y.; Chen, M.; Zhang, Q.

    2015-12-01

    Despite extensive efforts on characterizing organic nitrogen (ON) compounds in atmospheric aerosols and aqueous droplets, knowledge of ON chemistry is still limited, mainly due to its chemical complexity and lack of highly time-resolved measurements. This work is aimed at optimizing the method of using Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) to characterize ON compounds in atmospheric aerosols. Seventy-five pure nitrogen-containing organic compounds covering a variety of functional groups were analyzed with the HR-AMS. Our results show that ON compounds commonly produce NHx+, NOx+, which are usually attributed to inorganic N species such as ammonium and nitrate, and CH2N+ at m/z = 28, which is rarely quantified in ambient aerosol due to large interference from N2+ in the air signal. As a result, using the nitrogen-to-carbon (N/C) calibration factor proposed by Aiken et al. (2008) on average leads to ~ 20% underestimation of N/C in ambient organic aerosol. A new calibration factor of 0.79 is proposed for determining the average N/C in organics. The relative ionization efficiencies (RIEs) of different ON species, on average, are found to be consistent with the default RIE value (1.4) for the total organics. The AMS mass spectral features of various types of ON species (amines, amides, amino acids, etc.) are examined and used for characterizing ON composition in ambient aerosols. Our results indicate that submicron organic aerosol measured during wintertime in Fresno, CA contains significant amounts of amino-compounds whereas more diversified ON species, including N-containing aromatic heterocycle (e.g., imidazoles), are observed in fog waters collected simultaneously. Our findings have important implications for understanding atmospheric ON behaviors via the widespread HR-AMS measurements of ambient aerosols and droplets.

  6. Star Photometry for the Characterization of Columnar Aerosol Properties

    NASA Astrophysics Data System (ADS)

    Perez-Ramirez, D.; Lyamani, H.; Olmo Reyes, F. J.; Alados-Arboledas, L.; Whiteman, D. N.; Aceituno, J.

    2015-12-01

    Knowledge of columnar aerosol particles at nighttime is essential to completely understand aerosol dynamics and so will largely improve aerosol models. However, the current knowledge columnar nighttime aerosol is poor due to the lack of continuous measurements partly associated with previous technological limitations. Here we present the development, set up, calibration and data quality algorithms for the star photometer at the station of Granada (37.16 N, 3.60 W, 680 m a.s.l.) in Spain. The main advantage of this instrument is that make uses of a CCD camera as detector allowing direct star flux measurements. Filters center at 380, 440, 500, 670, 880 and 1020 nm allows spectral aerosol optical depth (AOD) measurements. Among all the stars, only those that are isolated and possess constant extratarrestial flux are considered. Two methods for the calibration of the system at high mountain places are presented. The first one consists of doing a Langley calibration of a selected star together with measurements of other stars. From the Langley calibration, we transferred AOD and get the calibration constants for other stars. The second method is the Astronomical Langley Method that consists of dividing the measurements by the optical air mass and so more stable calibration constant are obtained. On the other hand, the atmospheric turbulence is important for very short exposure times (< 1 s) and so uncertainties in AOD are of ±0.02 for λ < 800nm and ±0.01 for λ > 800nm. The instrument operated continuously for more than four consecutive years and so a large database was created. Cloud screening and data quality algorithms following AERONET inheritance were developed. Basically, moving averages are applied with different temporal-windows combined with a procedure to detect outliers. On the other hand, with quality data guaranteed the analysis of day-to-night columnar aerosol properties is presented. Mean AOD(440 nm) (0.18 ± 0.10 and 0.19 ± 0.11 for daytime and

  7. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; Denjean, C.; Brogniez, G.; di Sarra, A.; Alados-Arboledas, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, T.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Waquet, F.; Wenger, J.; Zapf, P.

    2016-01-01

    levels of atmospheric pollutants or intense biomass burning events in the region. However, numerous mineral dust plumes were observed during the campaign, with the main sources located in Morocco, Algeria and Tunisia, leading to aerosol optical depth (AOD) values ranging between 0.2 and 0.6 (at 440 nm) over the western and central Mediterranean basins. One important point of this experiment concerns the direct observations of aerosol extinction onboard the ATR-42, using the CAPS system, showing local maxima reaching up to 150 M m-1 within the dust plume. Non-negligible aerosol extinction (about 50 M m-1) has also been observed within the marine boundary layer (MBL). By combining the ATR-42 extinction coefficient observations with absorption and scattering measurements, we performed a complete optical closure revealing excellent agreement with estimated optical properties. This additional information on extinction properties has allowed calculation of the dust single scattering albedo (SSA) with a high level of confidence over the western Mediterranean. Our results show a moderate variability from 0.90 to 1.00 (at 530 nm) for all flights studied compared to that reported in the literature on this optical parameter. Our results underline also a relatively low difference in SSA with values derived near dust sources. In parallel, active remote-sensing observations from the surface and onboard the F-20 aircraft suggest a complex vertical structure of particles and distinct aerosol layers with sea spray and pollution located within the MBL, and mineral dust and/or aged North American smoke particles located above (up to 6-7 km in altitude). Aircraft and balloon-borne observations allow one to investigate the vertical structure of the aerosol size distribution showing particles characterized by a large size (> 10 µm in diameter) within dust plumes. In most of cases, a coarse mode characterized by an effective diameter ranging between 5 and 10 µm, has been detected above the

  8. Meeting Review: Airborne Aerosol Inlet Workshop

    NASA Technical Reports Server (NTRS)

    Baumgardner, Darrel; Huebert, Barry; Wilson, Chuck

    1991-01-01

    Proceedings from the Airborne Aerosol Inlet Workshop are presented. The two central topics of discussion were the role of aerosols in atmospheric processes and the difficulties in characterizing aerosols. The following topics were discussed during the working sessions: airborne observations to date; identification of inlet design issues; inlet modeling needs and directions; objectives for aircraft experiments; and future laboratory and wind tunnel studies.

  9. Aerosol Layering Characterization Near the Gobi Desert by a Double Polarization Lidar System

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Boselli, A.; Sannino, A.; Song, C.; Spinelli, N.; Wang, X.

    2016-06-01

    In order to carry out 4-D (space and time) analysis of the atmospheric aerosol distribution and to make a characterization of their properties and time evolution, a transportable multi-wavelength, Elastic/Raman scanning lidar system with angular scanning capability has been realized. The system uses a diode pumped Nd:YAG laser source, specifically designed for this device, and a receiving systems able to detect elastic signals at 355, 532 and 1064 nm and Raman signals at 386, 407 and 607 nm. It also allows to perform aerosol depolarization measurements at both 355nm and 532nm. A first measurement campaign has been carried out in Dunhuang, North-West of China, in the region of the Gobi desert with the aims to study and characterize desert dust at source. Optical properties of aerosol layers developing in the atmosphere have been analyzed and lidar data are discussed in terms of profiles of aerosol backscatter coefficient at 355nm, 532nm, aerosol extinction coefficient at 355nm, aerosol depolarization ratio at 355nm and 532nm and water vapor mixing ratio. Depolarization ratio measured simultaneously at two wavelengths allowed also to study its dependence on the wavelength.

  10. Estimation of aerosol type from airborne hyperspectral data: a new technique designed for industrial plume characterization

    NASA Astrophysics Data System (ADS)

    Deschamps, A.; Marion, R.; Foucher, P.-Y.; Briottet, X.

    2012-11-01

    The determination of the aerosol type in a plume from remotely sensed data without any a priori knowledge is a challenging task. If several methods have already been developed to characterize the aerosols from multi or hyperspectral data, they are not suited for industrial particles, which have specific physical and optical properties, changing quickly and in a complex way with the distance from the source emission. From radiative transfer equations, we have developed an algorithm, based on a Look-Up Table approach, enabling the determination of the type of this kind of particles from hyperspectral data. It consists in the selection of pixels pairs, located at the transitions between two kinds of grounds (or between an illuminated and a shadow area), then in the comparison between normalized estimated Aerosol Optical Thicknesses (AOTs) and pre-calculated AOTs. The application of this algorithm to simulated data leads to encouraging results: the selection of only six pixels pairs allows the algorithm to differentiate aerosols emitted by a metallurgical plant from biomass burning particles, urban aerosols and particles from an oil depot explosion, regardless the size and the aerosol concentration. The algorithm performances are better for a relatively high AOT but the single scattering approximation does not enable the characterization of thick plumes (AOT above 2.0). However, the choice of transitions (type of grounds) does not seem to significantly affect the results.

  11. Exploring Atmospheric Aqueous Chemistry (and Secondary Organic Aerosol Formation) through OH Radical Oxidation Experiments, Droplet Evaporation and Chemical Modeling

    NASA Astrophysics Data System (ADS)

    Turpin, B. J.; Kirkland, J. R.; Lim, Y. B.; Ortiz-Montalvo, D. L.; Sullivan, A.; Häkkinen, S.; Schwier, A. N.; Tan, Y.; McNeill, V. F.; Collett, J. L.; Skog, K.; Keutsch, F. N.; Sareen, N.; Carlton, A. G.; Decesari, S.; Facchini, C.

    2013-12-01

    Gas phase photochemistry fragments and oxidizes organic emissions, making water-soluble organics ubiquitous in the atmosphere. My group and others have found that several water-soluble compounds react further in the aqueous phase forming low volatility products under atmospherically-relevant conditions (i.e., in clouds, fogs and wet aerosols). Thus, secondary organic aerosol can form as a result of gas followed by aqueous chemistry (aqSOA). We have used aqueous OH radical oxidation experiments coupled with product analysis and chemical modeling to validate and refine the aqueous chemistry of glyoxal, methylglyoxal, glycolaldehyde, and acetic acid. The resulting chemical model has provided insights into the differences between oxidation chemistry in clouds and in wet aerosols. Further, we conducted droplet evaporation experiments to characterize the volatility of the products. Most recently, we have conducted aqueous OH radical oxidation experiments with ambient mixtures of water-soluble gases to identify additional atmospherically-important precursors and products. Specifically, we scrubbed water-soluble gases from the ambient air in the Po Valley, Italy using four mist chambers in parallel, operating at 25-30 L min-1. Aqueous OH radical oxidation experiments and control experiments were conducted with these mixtures (total organic carbon ≈ 100 μM-C). OH radicals (3.5E-2 μM [OH] s-1) were generated by photolyzing H2O2. Precursors and products were characterized using electrospray ionization mass spectrometry (ESI-MS), ion chromatography (IC), IC-ESI-MS, and ultra high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Chemical modeling suggests that organic acids (e.g., oxalate, pyruvate, glycolate) are major products of OH radical oxidation at cloud-relevant concentrations, whereas organic radical - radical reactions result in the formation of oligomers in wet aerosols. Products of cloud chemistry and droplet evaporation have

  12. Comparison of cloud residual and background aerosol particle composition during the hill cap cloud experiment HCCT 2010 in Central Germany

    NASA Astrophysics Data System (ADS)

    Roth, A.; Mertes, S.; van Pinxteren, D.; Klimach, T.; Herrmann, H.; Schneider, J.; Borrmann, S.

    2013-12-01

    Physical and chemical characterization of cloud residual and background aerosol particles as well as aerosol-cloud interactions were investigated during the Hill Cap Cloud Thuringia (HCCT) experiment in September and October 2010 on the mountain site Schmücke (938m a.s.l.) in Germany. Background aerosol particles were sampled by an interstitial inlet whereas cloud droplets from orographic clouds were collected by a counter flow virtual impactor (CVI). Chemical composition analysis and sizing of the particles was done by single particle mass spectrometry using the bipolar Aircraft-based Laser Ablation Aerosol Mass Spectrometer (ALABAMA, particle diameter range 150 nm - 900 nm; Brands et al., 2011) and by two Aerodyne Aerosol Mass Spectrometers (C-ToF, HR-ToF). Supplementary, the particle size distribution was measured with an optical particle counter (OPC, size range 0.25 μm - 32 μm). During the field campaign about 21000 positive and negative single particle mass spectra could be obtained from cloud residual particles and about 239000 from background aerosol particles. The data were clustered by means of the fuzzy c-means algorithm. The resulting clusters consisting of mass spectra with similar fragmentation patterns were, dependent on presence and combination of peaks, assigned to certain particle types. For both sampled particle types a large portion is internally mixed with nitrate and/or sulfate. This might be an explanation, why a comparison of the composition shows a higher fraction of soot particles and amine-containing particles among cloud residuals. Furthermore cloud residuals show a decreased fraction of particles being internally mixed only with nitrate (10%) compared to background aerosol particles (19%) of the same air masses, whereas the fraction of particles containing both nitrate and sulfate increases from 39% to 63% indicating cloud processing by uptake and oxidation of SO2 (Harris et al, 2013). Brands, M., Kamphus, M., Böttger, T., Schneider

  13. Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS)

    NASA Technical Reports Server (NTRS)

    Gasbarre, Joseph; Walker, Richard; Cisewski, Michael; Zawodny, Joseph; Cheek, Dianne; Thornton, Brooke

    2015-01-01

    The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) mission will extend the SAGE data record from the ideal vantage point of the International Space Station (ISS). The ISS orbital inclination is ideal for SAGE measurements providing coverage between 70 deg north and 70 deg south latitude. The SAGE data record includes an extensively validated data set including aerosol optical depth data dating to the Stratospheric Aerosol Measurement (SAM) experiments in 1975 and 1978 and stratospheric ozone profile data dating to the Stratospheric Aerosol and Gas Experiment (SAGE) in 1979. These and subsequent data records, notably from the SAGE II experiment launched on the Earth Radiation Budget Satellite in 1984 and the SAGE III experiment launched on the Russian Meteor-3M satellite in 2001, have supported a robust, long-term assessment of key atmospheric constituents. These scientific measurements provide the basis for the analysis of five of the nine critical constituents (aerosols, ozone (O3), nitrogen dioxide (NO2), water vapor (H2O), and air density using O2) identified in the U.S. National Plan for Stratospheric Monitoring. SAGE III on ISS was originally scheduled to fly on the ISS in the same timeframe as the Meteor-3M mission, but was postponed due to delays in ISS construction. The project was re-established in 2009.

  14. Characterization of aerosol properties from polarimetric satellite observations using GRASP algorithm

    NASA Astrophysics Data System (ADS)

    Dubovik, Oleg; Litvinov, Pavel; Lapyonok, Tatyana; Ducos, Fabrice; Huang, Xin; Lopatin, Anton; Fuertes, David; Derimian, Yevgeny

    2016-04-01

    GRASP (Generalized Retrieval of Aerosol and Surface Properties) is recently developed (Dubovik et al. 2011, 2014) sophisticated algorithm of new generation. The algorithm retrieves aerosol and surface properties simultaneously. It realizes statistically optimized fitting using multi-pixel concept when the retrieval is implemented simultaneously for a large group of satellite pixels. This allows for using additional a priori information about limited variability of aerosol of surface properties in time and/or space. GPASP searches in continuous space of solutions and doesn't utilize look-up-tables. GRASP doesn't use any location specific information about aerosol or surface type in the each observed pixel, and the results are essentially driven by observations. However GRASP retrieval takes longer computational time compare to most conventional algorithms. This main practical challenge of employing GRASP has been addressed during last two years and GRASP algorithm has been significantly optimized and adapted to operational needs. As a result of this optimization and GRASP has been accelerated to the level acceptable for processing large volumes of satellite observations. Recently GRASP has been applied to multi-years archives of PARASO/POLDER. The analysis of the results shows that GRASP retrievals provide rather robust and comprehensive aerosol characterization including such properties as absorption and aerosol type even for observations over bright surfaces and for monitoring very high aerosol loading events (with AOD up to 3 or 4). In addition, the attempts to estimate such aerosol characteristics as aerosol height, air quality, radiative forcing, etc. have been made. The results and illustrations will be presented.

  15. 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.

  16. Characterization of ice-nucleating bacteria using on-line electron impact ionization aerosol mass spectrometry.

    PubMed

    Wolf, R; Slowik, J G; Schaupp, C; Amato, P; Saathoff, H; Möhler, O; Prévôt, A S H; Baltensperger, U

    2015-04-01

    The mass spectral signatures of airborne bacteria were measured and analyzed in cloud simulation experiments at the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) facility. Suspensions of cultured cells in pure water were sprayed into the aerosol and cloud chambers forming an aerosol which consisted of intact cells, cell fragments and residual particles from the agar medium in which the bacteria were cultured. The aerosol particles were analyzed with a high-resolution time-of-flight aerosol mass spectrometer equipped with a newly developed PM2.5 aerodynamic lens. Positive matrix factorization (PMF) using the multilinear engine (ME-2) source apportionment was applied to deconvolve the bacteria and agar mass spectral signatures. The bacteria mass fraction contributed between 75 and 95% depending on the aerosol generation, with the remaining mass attributed to agar. We present mass spectra of Pseudomonas syringae and Pseudomonas fluorescens bacteria typical for ice-nucleation active bacteria in the atmosphere to facilitate the distinction of airborne bacteria from other constituents in ambient aerosol, e.g. by PMF/ME-2 source apportionment analyses. Nitrogen-containing ions were the most salient feature of the bacteria mass spectra, and a combination of C4 H8 N(+) (m/z 70) and C5 H12 N(+) (m/z 86) may be used as marker ions. PMID:26149110

  17. Characterization of near-highway submicron aerosols in New York City with a high-resolution aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Sun, Y. L.; Zhang, Q.; Schwab, J. J.; Chen, W.-N.; Bae, M.-S.; Hung, H.-M.; Lin, Y.-C.; Ng, N. L.; Jayne, J.; Massoli, P.; Williams, L. R.; Demerjian, K. L.

    2012-02-01

    Knowledge of the variations of mass concentration, chemical composition and size distributions of submicron aerosols near roadways is of importance for reducing exposure assessment uncertainties in health effects studies. The goal of this study is to deploy and evaluate an Atmospheric Sciences Research Center-Mobile Laboratory (ASRC-ML), equipped with a suite of rapid response instruments for characterization of traffic plumes, adjacent to the Long Island Expressway (LIE) - a high-traffic highway in the New York City Metropolitan Area. In total, four measurement periods, two in the morning and two in the evening were conducted at a location approximately 30 m south of the LIE. The mass concentrations and size distributions of non-refractory submicron aerosol (NR-PM1) species were measured in situ at a time resolution of 1 min by an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer, along with rapid measurements (down to 1 Hz) of gaseous pollutants (e.g. HCHO, NO2, NO, O3, and CO2, etc.), black carbon (BC), and particle number concentrations and size distributions. Particulate organics varied dramatically during periods with high traffic influences from the nearby roadway. The variations were mainly observed in the hydrocarbon-like organic aerosol (HOA), a surrogate for primary OA from vehicle emissions. The inorganic species (sulfate, ammonium, and nitrate) and oxygenated OA (OOA) showed much smoother variations indicating minor impacts from traffic emissions. The concentration and chemical composition of NR-PM1 also varied differently on different days depending on meteorology, traffic intensity and vehicle types. Overall, organics dominated the traffic-related NR-PM1 composition (>60%) with HOA accounting for a major fraction of OA. The traffic-influenced organics showed two distinct modes in mass-weighted size distributions, peaking at ∼120 nm and 500 nm (vacuum aerodynamic diameter, Dva), respectively. OOA and inorganic species appear to be

  18. The Joint Aerosol-Monsoon Experiment: A New Challenge to Monsoon Climate Research

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.

    2008-01-01

    Aerosol and monsoon related droughts and floods are two of the most serious environmental hazards confronting more than 60% of the population of the world living in the Asian monsoon countries. In recent years, thanks to improved satellite and in-situ observations, and better models, great strides have been made in aerosol, and monsoon research respectively. There is now a growing body of evidence suggesting that interaction of aerosol forcing with water cycle dynamics in monsoon regions may substantially alter the redistribution of energy at the earth surface and in the atmosphere, and therefore significantly impact monsoon rainfall variability and long term trends. In this talk, I will describe issues related to societal needs, scientific background, and challenges in studies of aerosol-water cycle interaction in Asian monsoon regions. As a first step towards addressing these issues, the authors call for an integrated observation and modeling research approach aimed at the interactions between aerosol chemistry and radiative effects and monsoon dynamics of the coupled ocean-atmosphere-land system. A Joint Aerosol-Monsoon Experiment (JAMEX) is proposed for 2007-2011, with an enhanced observation period during 2008-09, encompassing diverse arrays of observations from surface, aircraft, unmanned aerial vehicles, and satellites of physical and chemical properties of aerosols, long range aerosol transport as well as meteorological and oceanographic parameters in the Indo-Pacific Asian monsoon region. JAMEX will leverage on coordination among many ongoing and planned national programs on aerosols and monsoon research in China, India, Japan, Nepal, Italy, US, as well as international research programs of the World Climate Research Program (WCRP) and the World Meteorological Organization (WMO).

  19. Multi- year Arctic and Antarctic aerosol chemical characterization

    NASA Astrophysics Data System (ADS)

    Udisti, Roberto; Becagli, Silvia; Caiazzo, Laura; Calzolai, Giulia; Cappelletti, David; Giardi, Fabio; Grotti, Marco; Malandrino, Mery; Nava, Silvia; Severi, Mirko; Traversi, Rita

    2016-04-01

    Long term measurements of aerosol chemical composition in polar region are particularly relevant to investigate potential climatic effects of atmospheric components arising from both natural and anthropogenic emissions. In order to improve our knowledge on the atmospheric load and chemical composition of polar aerosol, several measurements and sampling campaigns were carried out both in Antarctica and in the Arctic since 2005.The main results are here reported. As regard as Antarctica, a continuous all-year-round sampling of size-segregated aerosol was carried from 2005 to 2013 at Dome C (East Antarctica; 75° 60' S, 123° 200' E, 3220 m a.s.l. and 1100 km away from the nearest coast). Aerosol was collected by PM10 and PM2.5 samplers and by multi-stage impactors (Dekati 4-stage impactor). Chemical analysis was carried out by Ion Chromatography (ions composition) and ICP-MS (trace metals). Sea spray showed a sharp seasonal pattern, with winter (Apr-Nov) concentrations about ten times larger than summer (Dec-Mar). Besides, in winter, sea spray particles are mainly sub micrometric, while the summer size-mode is around 1-2 um. Meteorological analysis and air mass back trajectory reconstructions allowed the identification of two major air mass pathways: micrometric fractions for transport from the closer Indian-Pacific sector, and sub-micrometric particles for longer trajectories over the Antarctic Plateau. The markers of oceanic biogenic emission (methanesulfonic acid - MSA, and non-sea-salt sulphate) exhibit a seasonal cycle with summer maxima (Nov-Mar). Their size distributions show two modes (0.4- 0.7 um and 1.1-2.1 um) in early summer and just one sub-micrometric mode in full summer. The two modes are related to different transport pathways. In early summer, air masses came primarily from the Indian Ocean and spent a long time over the continent. The transport of sulphur compounds is related to sea spray aerosols and the resulting condensation of H2SO4 and MSA over

  20. Organic compounds present in the natural Amazonian aerosol: Characterization by gas chromatography-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Graham, Bim; Guyon, Pascal; Taylor, Philip E.; Artaxo, Paulo; Maenhaut, Willy; Glovsky, M. Michael; Flagan, Richard C.; Andreae, Meinrat O.

    2003-12-01

    As part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)-Cooperative LBA Airborne Regional Experiment (CLAIRE) 2001 campaign in July 2001, separate day and nighttime aerosol samples were collected at a ground-based site in Amazonia, Brazil, in order to examine the composition and temporal variability of the natural "background" aerosol. We used a high-volume sampler to separate the aerosol into fine (aerodynamic diameter, AD < 2.5 μm) and coarse (AD > 2.5 μm) size fractions and quantified a range of organic compounds in methanolic extracts of the samples by a gas chromatographic-mass spectrometric technique. The carbon fraction of the compounds could account for an average of 7% of the organic carbon (OC) in both the fine and coarse aerosol fractions. We observed the highest concentrations of sugars, sugar alcohols, and fatty acids in the coarse aerosol samples, which suggests that these compounds are associated with primary biological aerosol particles (PBAP) observed in the forest atmosphere. Of these, trehalose, mannitol, arabitol, and the fatty acids were found to be more prevalent at night, coinciding with a nocturnal increase in PBAP in the 2-10 μm size range (predominantly yeasts and other small fungal spores). In contrast, glucose, fructose, and sucrose showed persistently higher daytime concentrations, coinciding with a daytime increase in large fungal spores, fern spores, pollen grains, and, to a lesser extent, plant fragments (generally >20 μm in diameter), probably driven by lowered relative humidity and enhanced wind speeds/convective activity during the day. For the fine aerosol samples a series of dicarboxylic and hydroxyacids were detected with persistently higher daytime concentrations, suggesting that photochemical production of a secondary organic aerosol from biogenic volatile organic compounds may have made a significant contribution to the fine aerosol. Anhydrosugars (levoglucosan, mannosan, galactosan), which are

  1. Characterization of a head-only aerosol exposure system for nonhuman primates.

    PubMed

    Dabisch, P A; Kline, J; Lewis, C; Yeager, J; Pitt, M L M

    2010-02-01

    A well-characterized exposure chamber is necessary to generate reproducible atmospheres for inhalation toxicology studies. The aim of the present study was to characterize a head-only exposure chamber for non-human primates. Aerosols containing bovine serum albumin (BSA) were used to characterize a 16-L dynamic airflow head-only exposure chamber. A 250-ml plastic bottle with a respirator attached located inside the chamber was used to simulate a breathing head. Chamber leak rate, mixing, and aerosol spatial distributions were quantified. The chamber concentration profile was measured at the chamber exhaust using an aerodynamic particle sizer. Aerosol spatial distribution was determined by collecting filter samples at several chamber locations. The particle size distribution was determined by collecting cascade impactor samples at several chamber locations. The estimated chamber leak rate was within standards suggested in the literature. The measured average aerosol residence time was similar to theoretical aerosol residence time, suggesting that the chamber was mixing well. Additionally, the average concentration measured at each of the sampling locations within the chamber was similar, and the within-run coefficients of variation (CV) across all sampling locations was similar to those reported in previously published studies, again suggesting that the aerosol concentration throughout the chamber was uniform. The particle size distribution was similar throughout the exposure chamber. Additionally, the BSA concentration and particle size distributions measured in the breathing zone of the simulated head were not significantly different from measurements made elsewhere in the chamber, suggesting that respiration does not affect the average aerosol concentration or particle size distribution at the mouth. PMID:20063997

  2. Chemical characterization of springtime submicrometer aerosol in Po Valley, Italy

    NASA Astrophysics Data System (ADS)

    Saarikoski, S.; Carbone, S.; Decesari, S.; Giulianelli, L.; Angelini, F.; Canagaratna, M.; Ng, N. L.; Trimborn, A.; Facchini, M. C.; Fuzzi, S.; Hillamo, R.; Worsnop, D.

    2012-09-01

    The chemistry of submicron particles was investigated at San Pietro Capofiume (SPC) measurement station in the Po Valley, Italy, in spring 2008. The measurements were performed by using both off-line and on-line instruments. Organic carbon (OC) and elemental carbon, organic acids and biomass burning tracers were measured off-line by using a 24-h PM1 filter sampling. More detailed particle chemistry was achieved by using a Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and analyzing the data by positive matrix factorization (PMF). Oxalic acid had the highest concentrations of organic acids (campaign-average 97.4 ng m-3) followed by methane sulfonic, formic, malonic, and malic acids. Samples were also analyzed for glyoxylic, succinic, azelaic and maleic acids. In total, the nine acids composed 1.9 and 3.8% of OC and water-soluble OC, respectively (average), in terms of carbon atoms. Levoglucosan concentration varied from 17.7 to 495 ng m-3 with the concentration decreasing in the course of the campaign most likely due to the reduced use of domestic heating with wood. Six factors were found for organic aerosol (OA) at SPC by PMF: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), nitrogen-containing OA (N-OA) and three different oxygenated OAs (OOA-a, OOA-b and OOA-c). Most of the OA mass was composed of OOA-a, HOA and OOA-c (26, 24 and 22%, respectively) followed by OOA-b (13%), BBOA (8%) and N-OA (7%). As expected, OOAs were the most oxygenated factors with organic matter:organic carbon (OM : OC) ratios ranging from 1.9 to 2.2. The diurnal variability of the aerosol chemical composition was greatly affected by the boundary layer meteorology. Specifically, the effect of the nocturnal layer break-up in morning hours was most evident for nitrate and N-OA indicating that these compounds originated mainly from the local sources in the Po Valley. For sulfate and OOA-a the concentration did not change during the break-up suggesting their

  3. Chemical characterization of springtime submicrometer aerosol in Po Valley, Italy

    NASA Astrophysics Data System (ADS)

    Saarikoski, S.; Carbone, S.; Decesari, S.; Giulianelli, L.; Angelini, F.; Teinilä, K.; Canagaratna, M.; Ng, N. L.; Trimborn, A.; Facchini, M. C.; Fuzzi, S.; Hillamo, R.; Worsnop, D.

    2012-03-01

    The chemistry of submicron particles was investigated at San Pietro Capofiume (SPC) measurement station in the Po Valley, Italy, in spring 2008. The measurements were performed by using both off-line and on-line instruments. Organic carbon (OC) and elemental carbon, organic acids and biomass burning tracers were measured off-line by using a 24-h PM1 filter sampling. More detailed particle chemistry was achieved by using an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and analyzing the data by positive matrix factorization (PMF). Oxalic acid had the highest concentrations of organic acids (campaign-average 97.4 ng m-3) followed by methane sulfonic, formic, malonic, and malic acids. Samples were also analyzed for glyoxylic, succinic, azelaic and maleic acids. In total, the nine acids composed 1.9 and 3.8% of OC and water-soluble OC, respectively (average), in terms of carbon atoms. Levoglucosan concentration varied from 17.7 to 495 ng m-3 with the concentration decreasing in the course of the campaign most likely due to the reduced use of domestic heating with wood. Six factors were found for organic aerosol (OA) at SPC by PMF: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), nitrogen-containing OA (N-OA) and three different oxygenated OAs (OOA-a, OOA-b and OOA-c). Most of the OA mass was composed of OOA-a, HOA and OOA-c (26, 24 and 22%, respectively) followed by OOA-b (13%), BBOA (8%) and N-OA (7%). As expected, OOAs were the most oxygenated factors with organic matter:organic carbon (OM:OC) ratios ranging from 1.9 to 2.2. The diurnal variability of the aerosol chemical composition was greatly affected by the boundary layer meteorology. Specifically, the effect of the nocturnal layer break-up in morning hours was most evident for nitrate and N-OA indicating that these compounds originated mainly from the local sources in the Po Valley. For sulfate and OOA-a the concentration did not change during the break-up suggesting their

  4. Molecular Characterization of Free Tropospheric Aerosol Collected at the Pico Mountain Observatory

    NASA Astrophysics Data System (ADS)

    Dzepina, K.; Mazzoleni, C.; Fialho, P. J.; China, S.; Zhang, B.; Owen, R. C.; Helmig, D.; Jacques, H.; Kumar, S.; Perlinger, J. A.; Kramer, L. J.; Dziobak, M.; Ampadu, M.; Olsen, S. C.; Wuebbles, D. J.; Mazzoleni, L. R.

    2014-12-01

    the two samples was corroborated by the changes in ozone, ethane, propane, morphology of particles, as well as by the FLEXPART retroplumes. In this presentation we will report the first detailed molecular characterization of free tropospheric aged aerosol intercepted at the Pico Mountain Observatory.

  5. Developing a broad spectrum atmospheric aerosol characterization for remote sensing platforms over desert regions

    NASA Astrophysics Data System (ADS)

    Strong, Shadrian B.; Brown, Andrea M.

    2014-05-01

    Remotely sensed imagery of targets embedded in Earth's atmosphere requires characterization of aerosols between the space-borne sensor and ground to accurately analyze observed target signatures. The impact of aerosol microphysical properties on retrieved atmospheric radiances has been shown to negatively affect the accuracy of remotely sensed data collects. Temporally and regionally specific meteorological conditions require exact site atmospheric characterization, involving extensive and timely observations. We present a novel methodology which fuses White Sands New Mexico regional aerosol micro pulse lidar (MPL) observations with sun photometer direct and diffuse products for broad-wavelength (visible - longwave infrared) input into the radiative transfer model MODTRAN5. Resulting radiances are compared with those retreived from the NASA Aqua MODIS instrument.

  6. Characterization of aerosol episodes in the greater Mediterranean Sea area from satellite observations (2000-2007)

    NASA Astrophysics Data System (ADS)

    Gkikas, A.; Hatzianastassiou, N.; Mihalopoulos, N.; Torres, O.

    2016-03-01

    An algorithm able to identify and characterize episodes of different aerosol types above sea surfaces of the greater Mediterranean basin (GMB), including the Black Sea and the Atlantic Ocean off the coasts of Iberia and northwest Africa, is presented in this study. Based on this algorithm, five types of intense (strong and extreme) aerosol episodes in the GMB are identified and characterized using daily aerosol optical properties from satellite measurements, namely MODIS-Terra, Earth Probe (EP)-TOMS and OMI-Aura. These aerosol episodes are: (i) biomass-burning/urban-industrial (BU), (ii) desert dust (DD), (iii) dust/sea-salt (DSS), (iv) mixed (MX) and (v) undetermined (UN). The identification and characterization is made with our algorithm using a variety of aerosol properties, namely aerosol optical depth (AOD), Ångström exponent (α), fine fraction (FF), effective radius (reff) and Aerosol Index (AI). During the study period (2000-2007), the most frequent aerosol episodes are DD, observed primarily in the western and central Mediterranean Sea, and off the northern African coasts, 7 times/year for strong episodes and 4 times/year for extreme ones, on average. The DD episodes yield 40% of all types of strong aerosol episodes in the study region, while they account for 71.5% of all extreme episodes. The frequency of occurrence of strong episodes exhibits specific geographical patterns, for example the BU are mostly observed along the coasts of southern Europe and off the Atlantic coasts of Portugal, the MX episodes off the Spanish Mediterranean coast and over the Adriatic and northern Aegean Sea, while the DSS ones over the western and central Mediterranean Sea. On the other hand, the extreme episodes for all but DD aerosol display more patchy spatial patterns. The strong episodes exhibit AOD at 550 nm as high as 1.6 in the southernmost parts of central and eastern Mediterranean Sea, which rise up to 5 for the extreme, mainly DD and DSS, episodes. Although more

  7. Ultrahigh resolution mass spectrometric characterization of organic aerosol from European and Chinese cities

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Huang, Ru-Jin; Hoffmann, Thorsten

    2016-04-01

    Organic aerosol constitutes a substantial fraction (20-90%) of submicrometer aerosol mass, playing an important role in air quality and human health. Over the past few years, ultra-high resolution mass spectrometry (UHRMS) has been applied to elucidate the chemical composition of ambient aerosols. However, most of the UHRMS studies used direct infusion without prior separation by liquid chromatography, which may cause the loss of individual compound information and interference problems. In the present study, urban ambient aerosol with particle diameter < 2.5 μm was collected in Mainz, Germany and Beijing, China, respectively. Two pretreatment procedures were applied to extract the organic compounds from the filter samples: One method uses a mixture of acetonitrile and water, the other uses pure water and prepared for the extraction of humic-like substances. The extracts were analyzed by ultra-high-performance liquid chromatography coupled with an Orbitrap mass spectrometer in both negative and the positive modes. The effects of pretreatment procedures on the characterization of organic aerosol and the city-wise difference in chemical composition of organic aerosol will be discussed in detail.

  8. Aerosol characterization over the southeastern United States using high resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition, sources, and organic nitrates

    NASA Astrophysics Data System (ADS)

    Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

    2015-04-01

    We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particles (NR-PM1) in the southeastern US. Measurements were performed in both rural and urban sites in the greater Atlanta area, GA and Centreville, AL for approximately one year, as part of Southeastern Center of Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important but not dominant contributions to total OA in urban sites. Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA (Isoprene-OA) is only deconvolved in warmer months and contributes 18-36% of total OA. The presence of Isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79%) of OA in all sites. MO-OOA correlates well with ozone in summer, but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based on the HR-ToF-AMS measurements, we estimate that the nitrate functionality from organic nitrates

  9. ARM Cloud Aerosol Precipitation Experiment (ACAPEX) Science Plan

    SciTech Connect

    Leung, L. R.; Prather, K.; Ralph, R.; Rosenfeld, D.; Spackman, R.; DeMott, P.; Fairall, C.; Fan, J.; Hagos, S.; Hughes, M.; Long, C.; Rutledge, S.; Waliser, D.; Wang, H.

    2014-09-01

    The western U.S. receives precipitation predominantly during the cold season when storms approach from the Pacific Ocean. The snowpack that accumulates during winter storms provides about 70-90% of water supply for the region. Understanding and modeling the fundamental processes that govern the large precipitation variability and extremes in the western U.S. is a critical test for the ability of climate models to predict the regional water cycle, including floods and droughts. Two elements of significant importance in predicting precipitation variability in the western U.S. are atmospheric rivers and aerosols. Atmospheric rivers (ARs) are narrow bands of enhanced water vapor associated with the warm sector of extratropical cyclones over the Pacific and Atlantic oceans. Because of the large lower-tropospheric water vapor content, strong atmospheric winds and neutral moist static stability, some ARs can produce heavy precipitation by orographic enhancement during landfall on the U.S. West Coast. While ARs are responsible for a large fraction of heavy precipitation in that region during winter, much of the rest of the orographic precipitation occurs in post-frontal clouds, which are typically quite shallow, with tops just high enough to pass the mountain barrier. Such clouds are inherently quite susceptible to aerosol effects on both warm rain and ice precipitation-forming processes.

  10. Characterization of aerosols above the Northern Adriatic Sea: Case studies of offshore and onshore wind conditions

    NASA Astrophysics Data System (ADS)

    Piazzola, J.; Mihalopoulos, N.; Canepa, E.; Tedeschi, G.; Prati, P.; Zarmpas, P.; Bastianini, M.; Missamou, T.; Cavaleri, L.

    2016-05-01

    Aerosol particles in coastal areas result from a complex mixing between sea spray aerosols locally generated at the sea surface by the wind-waves interaction processes and a continental component resulting from natural and/or anthropogenic sources. This paper presents a physical and chemical analysis of the aerosol data acquired from May to September 2014 in the Adriatic Sea. Aerosol distributions were measured on the Acqua Alta platform located 15 km off the coast of Venice using two Particle Measuring System probes and a chemical characterization was made using an Ion Chromatography analysis (IC). Our aim is to study both the sea-spray contribution and the anthropogenic influence in the coastal aerosol of this Mediterranean region. To this end, we focus on a comparison between the present data and the aerosol size distributions measured south of the French Mediterranean coast. For air masses of marine origin transported by southern winds on the French coast and by the Sirocco in the Adriatic, we note a good agreement between the concentrations of super-micrometer aerosols measured in the two locations. This indicates a similar sea surface production of sea-spray aerosols formed by bubble bursting processes in the two locations. In contrast, the results show larger concentrations of submicron particles in the North-Western Mediterranean compared to the Adriatic, which result probably from a larger anthropogenic background for marine conditions. In contrast, for a coastal influence, the chemical analysis presented in the present paper seems to indicate a larger importance of the anthropogenic impact in the Northern Adriatic compared to the North-Western Mediterranean.

  11. Characterizations of atmospheric fungal aerosol in Beijing, China

    NASA Astrophysics Data System (ADS)

    Liang, Linlin; Engling, Guenter; He, Kebin; Du, Zhenyu

    2013-04-01

    Fungal aerosols constitute the most abundant fraction of biological aerosols in the atmosphere, influencing human health, the biosphere, atmospheric chemistry and climate. However, the total abundance of fungal spores in the atmosphere is still poorly understood and quantified. PM10 and PM2.5 samples were collected by high volume samplers simultaneously at a rural site (MY) and an urban site (THU) in Beijing, China. Various carbohydrates were quantified by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), including the sugar alcohols mannitol and arabitol, proposed as molecular tracers for fungal aerosol. The annual average concentrations of arabitol in PM2.5 and PM10 at the THU site were 7.4±9.4 ng/m3 and 10.3±9.5 ng/m3, and the respective mannitol concentrations were 21.0±20.4 ng/m3 and 31.9±26.9 ng/m3. Compared to PM10, the monthly average concentrations of arabitol and mannitol in PM2.5 did not vary significantly and were present at nearly consistent levels in the different seasons. Moreover, during summer and autumn higher arabitol and mannitol levels than during spring and winter were observed in coarse particles, probably due to different dominant sources of fungal spores in different seasons. In the dry period (i.e., winter and spring) in Beijing, probably only the suspension from exposed surfaces, (e.g., soil resuspension, transported dust, etc.) can be regarded as the main sources for fungal aerosols. On the other hand, in summer and autumn, fungal spores in the atmosphere can be derived from more complex sources, including plants, vegetation decomposition and agricultural activity, such as ploughing; these fungal spore sources may contribute more to coarse PM. Mannitol and arabitol correlated well with each other, both in PM10 (R2 = 0.71) and PM2.5 (R2 = 0.81). Although fungal spore levels at rural sites were consistently higher than those at urban sites in other studies, the findings in our study were

  12. GC/MS Characterization of Fatty Acids Extracted From Southern African Aerosols

    NASA Astrophysics Data System (ADS)

    Shields, L. G.; Billmark, K. A.; Swap, R. J.; Macko, S. A.

    2001-12-01

    Fatty acids of total suspended particulate aerosol samples, collected in Mongu, Zambia during the Southern African Regional Science Initiative (SAFARI 2000) field campaign, were analyzed to characterize emissions from an important source of aerosols in the southern African region. The sample site was chosen specifically so as to decrease the influence of industrial emissions and to focus primarily on the emissions from biomass burning, of which fatty acids are a significant component. Previous investigations in southern Africa have identified emissions from biomass burning as a significant contributor to the haze layer prevalent across the subcontinent. In order to better understand the origins of the materials within the haze layer, characteristic compounds of different source materials were identified in the aerosols. This characterization may clarify the contributions to total aerosol loads from other sources, including marine aerosols or mineral dust. By determining the distributions and concentrations of distinct organic components, this study enables future investigations to quantify the contribution of emissions from biomass burning at specific geographic locations.

  13. The Stratospheric Aerosol and Gas Experiment III/International Space Station Mission: Science Objectives and Mission Status

    NASA Astrophysics Data System (ADS)

    Eckman, R.; Zawodny, J. M.; Cisewski, M. S.; Flittner, D. E.; McCormick, M. P.; Gasbarre, J. F.; Damadeo, R. P.; Hill, C. A.

    2015-12-01

    The Stratospheric Aerosol and Gas Experiment III/International Space Station (SAGE III/ISS) is a strategic climate continuity mission which was included in NASA's 2010 plan, "Responding to the Challenge of Climate and Environmental Change: NASA's Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space." SAGE III/ISS continues the long-term, global measurements of trace gases and aerosols begun in 1979 by SAGE I and continued by SAGE II and SAGE III on Meteor 3M. Using a well characterized occultation technique, the SAGE III instrument's spectrometer will measure vertical profiles of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gases relevant to ozone chemistry. The mission will launch in 2016 aboard a Falcon 9 spacecraft.The primary objective of SAGE III/ISS is to monitor the vertical distribution of aerosols, ozone, and other trace gases in the Earth's stratosphere and troposphere to enhance our understanding of ozone recovery and climate change processes in the stratosphere and upper troposphere. SAGE III/ISS will provide data necessary to assess the state of the recovery in the distribution of ozone, extend the SAGE III aerosol measurement record that is needed by both climate models and ozone models, and gain further insight into key processes contributing to ozone and aerosol variability. The multi-decadal SAGE ozone and aerosol data sets have undergone intense community scrutiny for accuracy and stability. SAGE ozone data have been used to monitor the effectiveness of the Montreal Protocol.The ISS inclined orbit of 51.6 degrees is ideal for SAGE III measurements because the orbit permits solar occultation measurement coverage to approximately +/- 70 degrees of latitude. SAGE III/ISS will make measurements using the solar occultation measurement technique, lunar occultation measurement technique, and the limb scattering measurement technique. In this presentation, we describe the SAGE III/ISS mission, its

  14. Electron Microscopy Characterization of Aerosols Collected at Mauna Loa Observatory During Asian Dust Storm Event

    EPA Science Inventory

    Atmospheric aerosol particles have a significant influence on global climate due to their ability to absorb and scatter incoming solar radiation. Size, composition, and morphology affect a particle’s radiative properties and these can be characterized by electron microscopy. Lo...

  15. Characterization of novel di- and tricarboxylic acids in fine tropical aerosols.

    PubMed

    Zdráhal, Z; Vermeylen, R; Claeys, M; Maenhaut, W; Guyon, P; Artaxo, P

    2001-04-01

    Three unknown di- and tricarboxylic acids were characterized in the fine size fraction of aerosols which were collected during the wet season in the Amazon basin (Rondonia, Brazil). For the structural characterization of the methyl esters of these unknown compounds, mass spectrometry with electron ionization (EI) and tandem mass spectral techniques combined with gas chromatographic (GC) separation were employed. Fragment and parent ion spectra were recorded during elution of the GC peaks by linked scanning of the B and E sectors in combination with high-energy collision-induced dissociation. The fragmentation patterns of significant ions in the first-order EI spectra were also obtained for nonanedioic acid, which was examined as a model compound. The compounds were tentatively identified as 4-acetyloxyheptanedioic acid and cis and trans isomers of 5-hexene-1,1,6-tricarboxylic acid. Since there were indications of biomass burning during the aerosol sampling the di- and tricarboxylic acids characterized in the present work could be markers for biomass burning. Furthermore, the characterization of di- and tricarboxylic acids in the fine size fraction of atmospheric aerosols may be important for assessing the effects of organic aerosols in cloud formation.

  16. Characterization of indoor cooking aerosol using neutron activation analysis

    SciTech Connect

    Wu, D.; Landsberger, S.; Larson, S. )

    1993-01-01

    Suspended particles in air are potentially harmful to human health, depending on their sizes and chemical composition. Residential indoor particles mainly come from (a) outdoor sources that are transported indoors, (b) indoor dust that is resuspended, and (c) indoor combustion sources, which include cigarette smoking, cooking, and heating. Jedrychowski stated that chronic phlegm in elderly women was strongly related to the cooking exposure. Kamens et al. indicated that cooking could generate small particles (<0.1 [mu]m), and cooking one meal could contribute [approximately]5 to 18% of total daytime particle volume exposure. Although cooking is a basic human activity, there are not many data available on the properties of particles generated by this activity. Some cooking methods, such as stir-frying and frying, which are the most favored for Chinese and other Far East people, generate a large quantity of aerosols. This research included the following efforts: 1. investigating particle number concentrations, distributions, and their variations with four different cooking methods and ventilation conditions; 2. measuring the chemical composition of cooking aerosol samples by instrumental neutron activation analysis.

  17. SPICAV/SOIR mesospheric aerosols observations and characterization

    NASA Astrophysics Data System (ADS)

    Wilquet, Valérie; Fedorova, Anna; Belyaev, Denis; Luginin, Mikhail; Drummond, Rachel; Mahieux, Arnaud; Robert, Séverine; Carine Vandaele, Ann; Montmessin, Franck; Bertaux, Jean-Loup

    2014-05-01

    SPICAV/SOIR on-board Venus Express is able to target the layer of aerosols above the cloud layer at the terminator in the 118-320 nm (SPICAV-UV), the 0.65-1.7 μm (SPICAV-IR) and the 2.2-4.3 μm (SOIR) spectral region. From independent retrievals for the 3 channels of the SPICAV/SOIR instrument, it has been postulated that the upper haze on Venus includes, in some instances, a bimodal population, one type of particle with a radius comprised between ~0.1 and 0.3 μm and the second type, detected in the IR, with a radius varying between ~0.4 and 1 μm [1]. In this work, the retrieval of the size distribution of aerosols in the upper haze of Venus was refined through a unique retrieval procedure combining the data from the 3 channels of the instrument. It is based on Mie theory and on the observed spectral dependence of light extinction in the spectra. A dependence on altitude of the aerosol particles size distribution and of aerosol composition is also investigated. We will present the analysis of a subset of SPICAV/SOIR orbits with simultaneous solar occultation transmission spectra for the 3 channels. The optical model was built using mean radius values (r1 and r2) between 0.01 μm and 1.0 μm. For bimodal size distributions, the ratio between the number of bigger particles and the number of smaller particles can vary between 10-4 and 10-1. Values of the refractive index for H2SO4/water droplets were found in the literature for concentrations between 64% and 87% H2SO4. First results show that the H2SO4 concentration in the particles decreases with increasing altitudes and that in some instances the fit of the extinction over the whole spectral range is improved when using a bimodal size distribution. At the equator, the upper haze is found at higher altitudes than near the North Pole and the H2SO4 concentration found is lower for a given aerosol loading. Next, we plan to extend the analysis to the full data set and to build an H2SO4 concentration gradient with

  18. Aerosol characterization over the North China Plain: Haze life cycle and biomass burning impacts in summer

    NASA Astrophysics Data System (ADS)

    Sun, Yele; Jiang, Qi; Xu, Yisheng; Ma, Yan; Zhang, Yingjie; Liu, Xingang; Li, Weijun; Wang, Fei; Li, Jie; Wang, Pucai; Li, Zhanqing

    2016-03-01

    The North China Plain experiences frequent severe haze pollution during all seasons. Here we present the results from a summer campaign that was conducted at Xianghe, a suburban site located between the megacities of Beijing and Tianjin. Aerosol particle composition was measured in situ by an Aerosol Chemical Speciation Monitor along with a suite of collocated measurements during 1-30 June 2013. Our results showed that aerosol composition at the suburban site was overall similar to that observed in Beijing, which was mainly composed of organics (39%), nitrate (20%), and sulfate (18%). Positive matrix factorization of organic aerosol (OA) identified four OA factors with different sources and processes. While secondary organic aerosol dominated OA, on average accounting for 70%, biomass burning OA (BBOA) was also observed to have a considerable contribution (11%) for the entire study period. The contribution of BBOA was increased to 21% during the BB period in late June, indicating a large impact of agricultural burning on air pollution in summer. Biomass burning also exerted a significant impact on aerosol optical properties. It was estimated that ~60% enhancement of absorption at the ultraviolet spectral region was caused by the organic compounds from biomass burning. The formation mechanisms and sources of severe haze pollution episodes were investigated in a case study. The results highlighted two different mechanisms, i.e., regional transport and local sources, driving the haze life cycles differently in summer in the North China Plain. While secondary aerosol species dominated aerosol composition in the episode from regional transport, organics and black carbon comprised the major fraction in the locally formed haze episode.

  19. Effects of Data Quality on the Characterization of Aerosol Properties from Multiple Sensors

    NASA Technical Reports Server (NTRS)

    Petrenko, Maksym; Ichoku, Charles; Leptoukh, Gregory

    2011-01-01

    Cross-comparison of aerosol properties between ground-based and spaceborne measurements is an important validation technique that helps to investigate the uncertainties of aerosol products acquired using spaceborne sensors. However, it has been shown that even minor differences in the cross-characterization procedure may significantly impact the results of such validation. Of particular consideration is the quality assurance I quality control (QA/QC) information - an auxiliary data indicating a "confidence" level (e.g., Bad, Fair, Good, Excellent, etc.) conferred by the retrieval algorithms on the produced data. Depending on the treatment of available QA/QC information, a cross-characterization procedure has the potential of filtering out invalid data points, such as uncertain or erroneous retrievals, which tend to reduce the credibility of such comparisons. However, under certain circumstances, even high QA/QC values may not fully guarantee the quality of the data. For example, retrievals in proximity of a cloud might be particularly perplexing for an aerosol retrieval algorithm, resulting in an invalid data that, nonetheless, could be assigned a high QA/QC confidence. In this presentation, we will study the effects of several QA/QC parameters on cross-characterization of aerosol properties between the data acquired by multiple spaceborne sensors. We will utilize the Multi-sensor Aerosol Products Sampling System (MAPSS) that provides a consistent platform for multi-sensor comparison, including collocation with measurements acquired by the ground-based Aerosol Robotic Network (AERONET), The multi-sensor spaceborne data analyzed include those acquired by the Terra-MODIS, Aqua-MODIS, Terra-MISR, Aura-OMI, Parasol-POLDER, and CalipsoCALIOP satellite instruments.

  20. Aerosolization, Chemical Characterization, Hygroscopicity and Ice Formation of Marine Biogenic Particles

    NASA Astrophysics Data System (ADS)

    Alpert, P. A.; Radway, J.; Kilthau, W.; Bothe, D.; Knopf, D. A.; Aller, J. Y.

    2013-12-01

    The oceans cover the majority of the earth's surface, host nearly half the total global primary productivity and are a major source of atmospheric aerosol particles. However, effects of biological activity on sea spray generation and composition, and subsequent cloud formation are not well understood. Our goal is to elucidate these effects which will be particularly important over nutrient rich seas, where microorganisms can reach concentrations of 10^9 per mL and along with transparent exopolymer particles (TEP) can become aerosolized. Here we report the results of mesocosm experiments in which bubbles were generated by two methods, either recirculating impinging water jets or glass frits, in natural or artificial seawater containing bacteria and unialgal cultures of three representative phytoplankton species, Thalassiosira pseudonana, Emiliania huxleyi, and Nannochloris atomus. Over time we followed the size distribution of aerosolized particles as well as their hygroscopicity, heterogeneous ice nucleation potential, and individual physical-chemical characteristics. Numbers of cells and the mass of dissolved and particulate organic carbon (DOC, POC), TEP (which includes polysaccharide-containing microgels and nanogels >0.4 μm in diameter) were determined in the bulk water, the surface microlayer, and aerosolized material. Aerosolized particles were also impacted onto substrates for ice nucleation and water uptake experiments, elemental analysis using computer controlled scanning electron microscopy and energy dispersive analysis of X-rays (CCSEM/EDX), and determination of carbon bonding with scanning transmission X-ray microscopy and near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Regardless of bubble generation method, the overall concentration of aerosol particles, TEP, POC and DOC increased as concentrations of bacterial and phytoplankton cells increased, stabilized, and subsequently declined. Particles <100 nm generated by means of jets

  1. A characterization of cloud base aerosol and associated microphysics in southeast Queensland

    NASA Astrophysics Data System (ADS)

    Tessendorf, S. A.; Arnold, C.; Bruintjes, R. T.; Axisa, D.; Peter, J.; Wilson, L.; Siems, S.; Manton, M.; May, P. T.; Stone, R.

    2009-12-01

    each of our cloud base measurements and classified them into four regimes by similar trajectory path (whether it was over land or ocean and north or south of Brisbane). From this we have studied the characteristics of the cloud base aerosol and CCN in each regime. The aerosol measurements in the more maritime regimes are cleaner, less variable, and tend to have more robust coarse mode aerosol sizes than those from continental sources. Furthermore, our preliminary measurements of initial DSDs in each regime suggests that the continental regimes exhibit more narrow droplet spectra, while the maritime regimes exhibit broader, but more variable, droplet spectra. Nonetheless, the total droplet concentrations are similar among all regimes, ranging from 100-800/cc. This paper will present the cloud base aerosol and CCN climatology from the Queensland CSRP field program and the cloud base aerosol measurements will be related to the initial cloud droplet spectra under each observed regime to characterize the influence of the cloud base aerosol on the cloud microphysics.

  2. Aerosol generation and characterization of multi-walled carbon nanotubes exposed to cells cultured at the air-liquid interface.

    PubMed

    Polk, William W; Sharma, Monita; Sayes, Christie M; Hotchkiss, Jon A; Clippinger, Amy J

    2016-04-23

    Aerosol generation and characterization are critical components in the assessment of the inhalation hazards of engineered nanomaterials (NMs). An extensive review was conducted on aerosol generation and exposure apparatus as part of an international expert workshop convened to discuss the design of an in vitro testing strategy to assess pulmonary toxicity following exposure to aerosolized particles. More specifically, this workshop focused on the design of an in vitro method to predict the development of pulmonary fibrosis in humans following exposure to multi-walled carbon nanotubes (MWCNTs). Aerosol generators, for dry or liquid particle suspension aerosolization, and exposure chambers, including both commercially available systems and those developed by independent researchers, were evaluated. Additionally, characterization methods that can be used and the time points at which characterization can be conducted in order to interpret in vitro exposure results were assessed. Summarized below is the information presented and discussed regarding the relevance of various aerosol generation and characterization techniques specific to aerosolized MWCNTs exposed to cells cultured at the air-liquid interface (ALI). The generation of MWCNT aerosols relevant to human exposures and their characterization throughout exposure in an ALI system is critical for extrapolation of in vitro results to toxicological outcomes in humans.

  3. Characterization of sources for southern African aerosols through fatty acid and trajectory analyses

    NASA Astrophysics Data System (ADS)

    Billmark, Kaycie A.; Swap, Robert J.; Macko, Stephen A.

    2003-07-01

    Biogeochemical cycles in southern Africa are affected by emissions from extensive biomass burning. Emitted trace gases and aerosols frequently accumulate and recirculate in the well-defined synoptic pattern that persists for long time periods over southern Africa. The role of organic aerosols during atmospheric transport and the influence of neighboring air masses on biogeochemical dynamics in this nutrient-limited region are insufficiently studied. The Southern African Regional Science Initiative (SAFARI 2000) was conducted in part to investigate the impacts of this large-scale transport and deposition of increasingly anthropogenic emissions on southern African biogeochemical cycling. This study explores the understanding of regional atmospheric transport through the identification of chemical biomarkers to describe aerosols collected during the SAFARI 2000 dry season research campaign. Total suspended particulate aerosol samples were collected diurnally for a period of two weeks in Mongu, Zambia. Mongu is bordered by the Zambezi River on the west and the Miombo woodland savanna in all other directions. It also lies on the northern extent of the Kalahari Desert. This region is characterized by high biomass burning emissions of river floodplain grasses and woodland savanna during the dry season. Fatty acids were extracted from the collected aerosols and analyzed using gas chromatography. The resultant fatty acid compositions were examined for temporal patterns and trends. Furthermore, these results were compared to both synoptic meteorological patterns over the region, as well as to modeled air parcel trajectories, to gain insight into changes in aerosol composition resulting from changes in atmospheric transports from regions of different vegetation. The results of these analyses confirm that abundances of fatty acids are dependent on local and synoptic meteorology and can thus be used as an additional geochemical tracer to better describe aerosol sources and

  4. Characterization of Atmospheric Aerosols in a Costa Rican Premontane Cloud Forest

    NASA Astrophysics Data System (ADS)

    Dennis, A. R.; Guffin, E. C.; Brooks, S. D.

    2012-12-01

    The composition and size of atmospheric aerosols are key to understanding both the direct effects of aerosols on climate and their role as cloud condensation nuclei (CCN). In this study, aerosols in a Costa Rican tropical premontane cloud forest were collected and analyzed by size, chemical composition, and source to determine their role in specific weather events and cloud formation. Particle concentration and size distributions were measured using a TSI AeroTrak spectrometer. A PIXE Cascade Impactor with two sampling stages was used to collect particles in the submicron and supermicron size ranges. To survey the biogenic component of aerosols, pollen particles were collected with a Rotorod Model 20. Aerosol and pollen samples were analyzed on "typical" and "event" days. Collected aerosol samples were analyzed for molecular functional groups present via Raman Microspectroscopy. AeroTrak collection showed particles in all size bins, with the majority of particles in the 0.3 μm bin. Typical days were consistently dominated by submicron particles. Event days were marked by strong and/or unusual wind speeds and directions, or heavy precipitation events. Concentrations of coarse particles were significantly increased during events. Raman analysis showed peaks at 2900, 1550, 1350, 1068, 450, and 141 wavenumbers, which indicate a mixture of organics, humic-like substances, nitrates, sulfates, and inorganic salts. Light microscopy analysis of pollen samples showed a large variability in daily pollen count with the greatest pollen count occurring on wind event days. Prevalent taxa of pollen identified were genus Pourouma in the Moraceae family, and Asteraceae family. Detailed characterization of the biogenic aerosol population present in the remote cloud forest will be presented and atmospheric implications discussed.

  5. Satellite Characterization of Fire Emissions of Aerosols and Gases Relevant to Air-Quality Modeling

    NASA Astrophysics Data System (ADS)

    Ichoku, C. M.; Ellison, L.; Yue, Y.; Wang, J.

    2015-12-01

    Because of the transient and widespread nature of wildfires and other types of open biomass burning, satellite remote sensing has become an indispensable technique for characterizing their smoke emissions for modeling applications, especially at regional to global scales. Fire radiative energy (FRE), whose instantaneous rate of release or fire radiative power (FRP) is measurable from space, has been found to be proportional to both the biomass consumption and emission of aerosol particulate matter. We have leveraged this relationship to generate a global, gridded smoke-aerosol emission coefficients (Ce) dataset based on FRP and aerosol optical thickness (AOT) measurements from the MODIS sensors aboard the Terra and Aqua satellites. Ce is a simple coefficient to convert FRE to smoke aerosol emissions, in the same manner as traditional emission factors are used to convert burned biomass to emissions. The first version of this Fire Energetics and Emissions Research (FEER.v1) global gridded Ce product at 1°x1° resolution is available at http://feer.gsfc.nasa.gov/. Based on published emission ratios, the FEER.v1 Ce product for total smoke aerosol has also been used to generate similar products for specific fire-emitted aerosols and gases, including those that are regulated as 'criteria pollutants' under the US Environmental Protection Agency's National Ambient Air Quality Standards (NAAQS), such as particulate matter (PM) and carbon monoxide (CO). These gridded Ce products were used in conjunction with satellite measurements of FRP to derive emissions of several smoke constituents, which were applied to WRF-Chem fully coupled meteorology-chemistry-aerosol model simulations, with promising results. In this presentation, we analyze WRF-Chem simulations of surface-level concentrations of various pollutants based on FEER.v1 emission products to illustrate their value for air-quality modeling, particularly in parts of Africa and southeast Asia where ground-based air

  6. Design and characterization of a smog chamber for studying gas-phase chemical mechanisms and aerosol formation

    NASA Astrophysics Data System (ADS)

    Wang, X.; Liu, T.; Bernard, F.; Ding, X.; Wen, S.; Zhang, Y.; Zhang, Z.; He, Q.; Lü, S.; Chen, J.; Saunders, S.; Yu, J.

    2014-01-01

    We describe here characterization of a new state-of-the-art smog chamber facility for studying atmospheric gas-phase and aerosol chemistry. The chamber consists of a 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor housed in a temperature-controlled enclosure equipped with black lamps as the light source. Temperature can be set in the range from -10 to 40 °C at accuracy of ±1 °C as measured by eight temperature sensors inside the enclosure and one just inside the reactor. Matrix air can be purified with non-methane hydrocarbons (NMHCs) < 0.5 ppb, NOx/O3/carbonyls < 1 ppb and particles < 1 cm-3. The photolysis rate of NO2 is adjustable between 0 and 0.49 min-1. At 298 K under dry conditions, the average wall loss rates of NO, NO2 and O3 were measured to be 1.41 × 10-4 min-1, 1.39 × 10-4 min-1 and 1.31 × 10-4 min-1, respectively, and the particle number wall loss rate was measured to be 0.17 h-1. Auxiliary mechanisms of this chamber are determined and included in the Master Chemical Mechanism to evaluate and model propene-NOx-air irradiation experiments. The results indicate that this new smog chamber can provide high-quality data for mechanism evaluation. Results of α-pinene dark ozonolysis experiments revealed secondary organic aerosol (SOA) yields comparable to those from other chamber studies, and the two-product model gives a good fit for the yield data obtained in this work. Characterization experiments demonstrate that our Guangzhou Institute of Geochemistry, Chinese Academy Sciences (GIG-CAS), smog chamber facility can be used to provide valuable data for gas-phase chemistry and secondary aerosol formation.

  7. The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment SALTRACE 2013 - Overview and Early Results (Invited)

    NASA Astrophysics Data System (ADS)

    Weinzierl, B.; Ansmann, A.; Reitebuch, O.; Freudenthaler, V.; Müller, T.; Kandler, K.; Althausen, D.; Busen, R.; Dollner, M.; Dörnbrack, A.; Farrell, D. A.; Gross, S.; Heimerl, K.; Klepel, A.; Kristensen, T. B.; Mayol-Bracero, O. L.; Minikin, A.; Prescod, D.; Prospero, J. M.; Rahm, S.; Rapp, M.; Sauer, D. N.; Schaefler, A.; Toledano, C.; Vaughan, M.; Wiegner, M.

    2013-12-01

    Mineral dust is an important player in the global climate system. In spite of substantial progress in the past decade, many questions in our understanding of the atmospheric and climate effects of mineral dust remain open such as the change of the dust size distribution during transport across the Atlantic Ocean and the associated impact on the radiation budget, the role of wet and dry dust removal mechanisms during transport, and the complex interaction between mineral dust and clouds. To close gaps in our understanding of mineral dust in the climate system, the Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE: http://www.pa.op.dlr.de/saltrace) was conducted in June/July 2013. SALTRACE is a German initiative combining ground-based and airborne in-situ and lidar measurements with meteorological data, long-term measurements, satellite remote sensing and modeling. During SALTRACE, the DLR research aircraft Falcon was based on Sal, Cape Verde, between 11 and 17 June, and on Barbados between 18 June and 11 July 2013. The Falcon was equipped with a suite of in-situ instruments for the measurement of microphysical and optical aerosol properties and with a nadir-looking 2-μm wind lidar. Ground-based lidar and in-situ instruments were deployed in Barbados and Puerto Rico. Mineral dust from several dust outbreaks was measured by the Falcon between Senegal and Florida. On the eastern side of the Atlantic, dust plumes extended up to 6 km altitude, while the dust layers in the Caribbean were mainly below 4.5 km. The aerosol optical thickness of the dust outbreaks studied ranged from 0.2 to 0.6 at 500 nm in Barbados. Highlights during SALTRACE included the sampling of a dust plume in the Cape Verde area on 17 June which was again measured with the same instrumentation on 21 and 22 June near Barbados. The event was also captured by the ground-based lidar and in-situ instrumentation. Another highlight was the formation of tropical storm

  8. Comparison of Aerosol Single Scattering Albedos Derived By Diverse Techniques in Two North Atlantic Experiments

    NASA Technical Reports Server (NTRS)

    Russell, P. B.; Redemann, J.; Schmid, B.; Bergstrom, R. W.; Livingston, J. M.; McIntosh, D. M.; Hartley, S.; Hobbs, P. V.; Quinn, P. K.; Carrico, C. M.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    Aerosol single scattering albedo w (the ratio of scattering to extinction) is important in determining aerosol climatic effects, in explaining relationships between calculated and measured radiative fluxes, and in retrieving aerosol optical depths from satellite radiances. Recently, two experiments in the North Atlantic region, TARFOX and ACE-2, determined aerosol w by a variety of techniques. The techniques included fitting of calculated to measured fluxes; retrievals of w from skylight radiances; best fits of complex refractive index to profiles of backscatter, extinction, and size distribution; and in situ measurements of scattering and absorption at the surface and aloft. Both TARFOX and ACE-2 found a fairly wide range of values for w at midvisible wavelengths, with 0.85 less than wmidvis less than 0.99 for the marine aerosol impacted by continental pollution. Frequency distributions of w could usually be approximated by lognormals in wmax-w, with some occurrence of bimodality, suggesting the influence of different aerosol sources or processing. In both TARFOX and ACE-2, closure tests between measured and calculated radiative fluxes yielded best-fit values of wmidvis of 0.90+/-0.04 for the polluted boundary layer. Although these results have the virtue of describing the column aerosol unperturbed by sampling, they are subject to questions about representativeness and possible artifacts (e.g., unknown gas absorption). The other techniques gave larger values for wmidvis for the polluted boundary layer, with a typical result of wmidvis = 0.95+/-0.04, Current uncertainties in vv are large in terms of climate effects. More tests are needed of the consistency among different methods and of humidification effects on w.

  9. Elemental composition of aerosols in fourteen experiments of the Cloud Condensation Nuclei Workshop

    NASA Technical Reports Server (NTRS)

    Mach, W. H.; Hucek, R. R.

    1981-01-01

    Aeosols were collected with two Ci impactors and analyzed with proton induced X-ray emission (PIXE) for chemical composition and to detect if contamination was present. One of the impactors sampled the generated aerosols; the other impactor sampled droplets from a diffusion cloud chamber. The purpose of the experiments was to test the feasibility of a study of the transfer of chemical elements from the fine particle sizes to the coarse particle sizes, after CCN are activated and cloud droplets are formed. The data indicated that sulfur-containing aerosols did exhibit the expected transfer.

  10. Developments and plans for new drifting balloon experiments in the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) project

    NASA Astrophysics Data System (ADS)

    Dulac, François; Durand, Pierre; Verdier, Nicolas; Renard, Jean-Baptiste; Mallet, Marc; Thouret, Valérie; Attié, Jean-Luc

    ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr) is a new integrated project which aims at an assessment of the present state of the atmospheric environment in the Mediterranean basin, of its impacts on air quality, regional climate and marine biogeochemistry, and of their evolution in a regional context of intense climate change and increasing anthropogenic pressure. The Mediterranean is indeed characterized by a long dry and sunny season with high concentrations of aerosols and gaseous pollutants such as ozone. ChArMEx plans large international coordinated field campaigns with surface stations and airborne platforms including drifting balloons for studying the ageing of continental air masses transported over the basin. We are willing to deploy two types of balloons: (i) The Aeroclipper is a low altitude streamlined balloon drifting at 50 m over the sea surface and equipped with a cable and a guide-rope in contact with the surface ocean. It moves on a quasi-Lagrangian trajectory depending on the surface wind and marine current. Its instru-mentation is distributed on one atmospheric gondola and one oceanic gondola with the aim to measure surface physical parameters (air and sea surface temperatures, wind, pressure and humidity) in order to derive turbulent fluxes of moisture, heat and momentum. (ii) The BPCL is a long duration super-pressure balloon designed to drift in the atmospheric boundary layer. It moves on a quasi-Lagrangian trajectory at an adjustable constant atmo-spheric density level which altitude ranges between a few hundreds of m and about 3 km. Its instrumentation includes air pressure, temperature and humidity. Both balloon types are equipped with a positioning system and a data transmission system. In addition we are developing new small instruments to be integrated in the payload of these two balloon types. This includes radiation sensors to measure visible and infrared fluxes, an optical particle counter

  11. Characterization of Electronic Cigarette Aerosol and Its Induction of Oxidative Stress Response in Oral Keratinocytes

    PubMed Central

    Zhao, Tongke; Shu, Shi; Chang, Chong Hyun; Messadi, Diana; Xia, Tian; Zhu, Yifang; Hu, Shen

    2016-01-01

    In this study, we have generated and characterized Electronic Cigarette (EC) aerosols using a combination of advanced technologies. In the gas phase, the particle number concentration (PNC) of EC aerosols was found to be positively correlated with puff duration whereas the PNC and size distribution may vary with different flavors and nicotine strength. In the liquid phase (water or cell culture media), the size of EC nanoparticles appeared to be significantly larger than those in the gas phase, which might be due to aggregation of nanoparticles in the liquid phase. By using in vitro high-throughput cytotoxicity assays, we have demonstrated that EC aerosols significantly decrease intracellular levels of glutathione in NHOKs in a dose-dependent fashion resulting in cytotoxicity. These findings suggest that EC aerosols cause cytotoxicity to oral epithelial cells in vitro, and the underlying molecular mechanisms may be or at least partially due to oxidative stress induced by toxic substances (e.g., nanoparticles and chemicals) present in EC aerosols. PMID:27223106

  12. MELCOR 1.8.2 assessment: Aerosol experiments ABCOVE AB5, AB6, AB7, and LACE LA2

    SciTech Connect

    Souto, F.J.; Haskin, F.E.; Kmetyk, L.N.

    1994-10-01

    The MELCOR computer code has been used to model four of the large-scale aerosol behavior experiments conducted in the Containment System Test Facility (CSTF) vessel. Tests AB5, AB6 and AB7 of the ABCOVE program simulate the dry aerosol conditions during a hypothetical severe accident in an LMFBR. Test LA2 of the LACE program simulates aerosol behavior in a condensing steam environment during a postulated severe accident in an LWR with failure to isolate the containment. The comparison of code results to experimental data show that MELCOR is able to correctly predict most of the thermal-hydraulic results in the four tests. MELCOR predicts reasonably well the dry aerosol behavior of the ABCOVE tests, but significant disagreements are found in the aerosol behavior modelling for the LA2 experiment. These results tend to support some of the concerns about the MELCOR modelling of steam condensation onto aerosols expressed in previous works. During these analyses, a limitation in the MELCOR input was detected for the specification of the aerosol parameters for more than one component. A Latin Hypercube Sampling (LHS) sensitivity study of the aerosol dynamic constants is presented for test AB6. The study shows the importance of the aerosol shape factors in the aerosol deposition behavior, and reveals that MELCOR input/output processing is highly labor intensive for uncertainty and sensitivity analyses based on LHS.

  13. Overview of the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate (ChArMEx/ADRIMED) summer 2013 campaign

    NASA Astrophysics Data System (ADS)

    Mallet, M.; Dulac, F.; Formenti, P.; Nabat, P.; Sciare, J.; Roberts, G.; Pelon, J.; Ancellet, G.; Tanré, D.; Parol, F.; di Sarra, A.; Alados, L.; Arndt, J.; Auriol, F.; Blarel, L.; Bourrianne, T.; Brogniez, G.; Chazette, P.; Chevaillier, S.; Claeys, M.; D'Anna, B.; Denjean, C.; Derimian, Y.; Desboeufs, K.; Di Iorio, T.; Doussin, J.-F.; Durand, P.; Féron, A.; Freney, E.; Gaimoz, C.; Goloub, P.; Gómez-Amo, J. L.; Granados-Muñoz, M. J.; Grand, N.; Hamonou, E.; Jankowiak, I.; Jeannot, M.; Léon, J.-F.; Maillé, M.; Mailler, S.; Meloni, D.; Menut, L.; Momboisse, G.; Nicolas, J.; Podvin, J.; Pont, V.; Rea, G.; Renard, J.-B.; Roblou, L.; Schepanski, K.; Schwarzenboeck, A.; Sellegri, K.; Sicard, M.; Solmon, F.; Somot, S.; Torres, B.; Totems, J.; Triquet, S.; Verdier, N.; Verwaerde, C.; Wenger, J.; Zapf, P.

    2015-07-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx; http://charmex.lsce.ipsl.fr) is a collaborative research program federating international activities to investigate Mediterranean regional chemistry-climate interactions. A special observing period (SOP-1a) including intensive airborne measurements was performed in the framework of the Aerosol Direct Radiative Forcing on the Mediterranean Climate (ADRIMED) project during the Mediterranean dry season over the western and central Mediterranean basins, with a focus on aerosol-radiation measurements and their modeling. The SOP-1a took place from 11 June to 5 July 2013. Airborne measurements were made by both the ATR-42 and F-20 French research aircraft operated from Sardinia (Italy) and instrumented for in situ and remote-sensing measurements, respectively, and by sounding and drifting balloons, launched in Minorca. The experimental set-up also involved several ground-based measurement sites on islands including two ground-based reference stations in Corsica and Lampedusa and secondary monitoring sites in Minorca and Sicily. Additional measurements including lidar profiling were also performed on alert during aircraft operations at EARLINET/ACTRIS stations at Granada and Barcelona in Spain, and in southern Italy. Remote sensing aerosol products from satellites (MSG/SEVIRI, MODIS) and from the AERONET/PHOTONS network were also used. Dedicated meso-scale and regional modelling experiments were performed in relation to this observational effort. We provide here an overview of the different surface and aircraft observations deployed during the ChArMEx/ADRIMED period and of associated modeling studies together with an analysis of the synoptic conditions that determined the aerosol emission and transport. Meteorological conditions observed during this campaign (moderate temperatures and southern flows) were not favorable to produce high level of atmospheric pollutants nor

  14. Aerosol and melt chemistry in the ACE molten core-concrete interaction experiments

    SciTech Connect

    Fink, J.K.; Thompson, D.H.; Spencer, B.W.; Sehgal, B.R.

    1995-01-01

    Experimental results are discussed from the internationally sponsored Advanced Containment Experiments (ACE) Program on the melt behavior and aerosols released during the interaction of molten reactor core material with concrete. A broad range of parameters were addressed in the experimental program: Seven large-scale tests were performed using four types of concrete (siliceous, limestone/sand, serpentine, and limestone) and a range of metal oxidations for both boiling water and pressurized waster reactor core debris. The release aerosols contained mainly constitutents of the concrete. In the tests with metal and limestone/sand siliceous concrete, silicon compounds comprised 50% or more of the aerosol mass. Releases of uranium and low-volatility fission-product elements were small in all tests. Releases of tellurium and neutron absorber materials (silver, indium, and boron from boron carbide) were high.

  15. Analytical pyrolysis experiments of Titan aerosol analogues in preparation for the Cassini Huygens mission

    NASA Technical Reports Server (NTRS)

    Ehrenfreund, P.; Boon, J. J.; Commandeur, J.; Sagan, C.; Thompson, W. R.; Khare, B.

    1995-01-01

    Comparative pyrolysis mass spectrometric data of Titan aerosol analogs, called 'tholins', are presented. The Titan tholins were produced in the laboratory at Cornell by irradiation of simulated Titan atmospheres with high energy electrons in plasma discharge. Mass-spectrometry measurements were performed at FOM of the solid phase of various tholins by Curie-point pyrolysis Gas-Chromatography/Mass-Spectrometry (GCMS) and by temperature resolved in-source Pyrolysis Mass-Spectrometry to reveal the composition and evolution temperature of the dissociation products. The results presented here are used to further define the ACP (Aerosol Collector Pyrolyser)-GCMS experiment and provide a basis for modelling of aerosol composition on Titan and for the iterpretation of Titan atmosphere data from the Huygens probe in the future.

  16. Real-time aerosol data assimilation experiments during the 2014 FRAPPE/DISCOVER-AQ field mission

    NASA Astrophysics Data System (ADS)

    Pierce, R. B.

    2014-12-01

    The Front Range Air Pollution and Photochemistry Experiment (FRAPPE) and Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field missions were conducted over the Front Range of Colorado during July and August, 2014. Prior to, and during this period, much of the continental US were impacted by smoke from Canadian and Pacific Northwest wildfires, including the Front Range. This study assesses the impact of real-time assimilation of Aerosol Optical Depth (AOD) retrievals from the MODIS instrument on NASA's Terra and Aqua satellites within the Real-time Air Quality Modeling System (RAQMS) through comparisons of aerosol predictions with observations for two parallel forecasts that were conducted during FRAPPE/DISCOVER-AQ, one with and one without MODIS AOD assimilation. Results of these real-time assimilation experiments demonstrate that assimilation of MODIS AOD improves the prediction of large-scale smoke events such as those that occurred during July and August, 2014. These assimilation experiments help to guide the development of future operational aerosol forecasting systems within the NOAA Environmental Modeling System (NEMS) Global Forecasting System (GFS) Aerosol Component (NGAC) under development at the National Centers for Environmental Prediction (NCEP).

  17. Stratospheric ozone variations in the equatorial region as seen in Stratiospheric Aerosol and Gas Experiment data

    SciTech Connect

    Shiotani, M.; Hasebe, F. |

    1994-07-01

    An analysis is made of equatorial ozone variations for 5 years, 1984-1989, using the ozone profile data derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. Attention is focused on the annual cycle and also on interannual variability, particularly the quasi-biennial oscillation (QBO) and El Nino-Southern Oscillation (ENSO) variations in the lower stratosphere, where the largest contribution to total column ozone takes place. The annual variation in zonal mean total ozone around the equator is composed of symmetric and asymmetric modes with respect to the equator, with maximum contributions being around 19 km for the symmetric mode and around 25 km for the asymmetric mode. The persistent zonal wavenumber 1 structure observed by the total ozone mapping spectrometer over the equator is almost missing in the SAGE-derived column amounts integrated in the stratosphere, suggesting a significant contribution from tropospheric ozone. Interannual variations in the equatorial ozone are dominated by the QBO above 20 km and the ENSO-related variation below 20 km. The ozone QBO is characterized by zonally uniform phase changes in association with the zonal wind QBO in the equatorial lower stratosphere. The ENSO-related ozone variation consists of both the east-west vacillation and the zonally uniform phase variation. During the El Nino event, the east-west contrast with positive (negative) deviations in the eastern (western) hemisphere is conspicuous, while the decreasing tendency of the zonal mean values is maximum at the same time.

  18. Stratospheric ozone variations in the equatorial region as seen in Stratiospheric Aerosol and Gas Experiment data

    NASA Technical Reports Server (NTRS)

    Shiotani, Masato; Hasebe, Fumio

    1994-01-01

    An analysis is made of equatorial ozone variations for 5 years, 1984-1989, using the ozone profile data derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument. Attention is focused on the annual cycle and also on interannual variability, particularly the quasi-biennial oscillation (QBO) and El Nino-Southern Oscillation (ENSO) variations in the lower stratosphere, where the largest contribution to total column ozone takes place. The annual variation in zonal mean total ozone around the equator is composed of symmetric and asymmetric modes with respect to the equator, with maximum contributions being around 19 km for the symmetric mode and around 25 km for the asymmetric mode. The persistent zonal wavenumber 1 structure observed by the total ozone mapping spectrometer over the equator is almost missing in the SAGE-derived column amounts integrated in the stratosphere, suggesting a significant contribution from tropospheric ozone. Interannual variations in the equatorial ozone are dominated by the QBO above 20 km and the ENSO-related variation below 20 km. The ozone QBO is characterized by zonally uniform phase changes in association with the zonal wind QBO in the equatorial lower stratosphere. The ENSO-related ozone variation consists of both the east-west vacillation and the zonally uniform phase variation. During the El Nino event, the east-west contrast with positive (negative) deviations in the eastern (western) hemisphere is conspicuous, while the decreasing tendency of the zonal mean values is maximum at the same time.

  19. The influence of fog parameters on aerosol depletion measured in the KAEVER experiments

    SciTech Connect

    Poss, G.; Weber, D.; Fritsche, B.

    1995-12-31

    The release of radioactive aerosols in the environment is one of the most serious hazards in case of an accident in nuclear power plant. Many efforts have been made in the past in numerous experimental programs like NSPP, DEMONA, VANAM, LACE, MARVIKEN, others are still underway to improve the knowledge of the aerosol behavior and depletion in a reactor containment in order to estimate the possible source term and to validate computer codes. In the German single compartment KAEVER facility the influence of size distribution, morphology, composition and solubility on the aerosol behavior is investigated. One of the more specific items is to learn about {open_quotes}wet depletion{close_quotes} means, the aerosol depletion behavior in condensing atmospheres. There are no experiments known where the fog parameters like droplet size distribution, volume concentration, respectively airborne liquid water content have been measured in- and on-line explicitly. To the authors knowledge the use of the Battelle FASP photometer, which was developed especially for this reason, for the first time gives insight in condensation behavior under accident typical thermal hydraulic conditions. It delivers a basis for code validation in terms of a real comparison of measurements and calculations. The paper presents results from {open_quotes}wet depletion{close_quotes} aerosol experiments demonstrating how depletion velocity depends on the fog parameters and where obviously critical fog parameter seem to change the regime from a {open_quotes}pseudo dry depletion{close_quotes} at a relative humidity of 100% but quasi no or very low airborne liquid water content to a real {open_quotes}wet depletion{close_quotes} under the presence of fogs with varying densities. Characteristics are outlined how soluble and insoluble particles as well as aerosol mixtures behave under condensing conditions.

  20. The hydrological assessment of aerosol effects by the idealized airborne cloud seeding experiment

    NASA Astrophysics Data System (ADS)

    Lee, K.; Lee, B.; Chae, S.; Lee, C.; Choi, Y.

    2012-12-01

    The main source of aerosols over East Asia including the Korean Peninsula is the anthropogenic emission of atmospheric pollutants transported from Chinese industrial areas. For this reason, the researches of aerosol effects are very active in East Asian countries. In case of South Korea, aircraft measurement campaigns and airborne cloud seeding experiments for the meteorological and environmental research have been conducted over the local area of Korean Peninsula since the year of 2010. This project is related with the weather modification research to build up strategies for the regulation or enhancement of precipitation and snowpack for a severe drought in South Korea during a winter season. For this study, the aerosol effect on precipitation by the airborne cloud seeding was simulated using WRF-CHEM model with RADM2/MADE,SORGAM modules. Emission data of 10000μg/(m2s) of unspeciated primary PM2.5 were input at 0.5km altitude for aerosol scenario cases which is the height of airborne cloud seeding experiment. For the control run, the original WRF model with no chemistry/aerosol modules was used. Also, the hydrological model, SWAT (Soil and Water Assessment Tool, USDA/ARS) is incorporated to evaluate this aerosol effects hydrologically for the enhancement of precipitation or snowfall from the results of WRF-CHEM model. The target area is the Andong dam basin (1,584 km2) which is known as one of the important water resources in southern part of South Korea. The date was chosen based on the conditions of airborne cloud seeding experiment (RH>50%, Low Temp.<-3°C, Wind Speeds<5m/s, etc). During the 24 forecasting hour, the aerosol scenario case showed more amounts of accumulated precipitation (about 12%) than those of control run. According to the analysis of SWAT, the enhancement of precipitation in aerosol scenario cases of WRF-CHEM model could influence the increase of about 1.0×106m3 water resources when we assumed the 10% of effective area over the Andong dam

  1. Characterization and parameterization of aerosol cloud condensation nuclei activation under different pollution conditions.

    PubMed

    Che, H C; Zhang, X Y; Wang, Y Q; Zhang, L; Shen, X J; Zhang, Y M; Ma, Q L; Sun, J Y; Zhang, Y W; Wang, T T

    2016-01-01

    To better understand the cloud condensation nuclei (CCN) activation capacity of aerosol particles in different pollution conditions, a long-term field experiment was carried out at a regional GAW (Global Atmosphere Watch) station in the Yangtze River Delta area of China. The homogeneity of aerosol particles was the highest in clean weather, with the highest active fraction of all the weather types. For pollution with the same visibility, the residual aerosol particles in higher relative humidity weather conditions were more externally mixed and heterogeneous, with a lower hygroscopic capacity. The hygroscopic capacity (κ) of organic aerosols can be classified into 0.1 and 0.2 in different weather types. The particles at ~150 nm were easily activated in haze weather conditions. For CCN predictions, the bulk chemical composition method was closer to observations at low supersaturations (≤0.1%), whereas when the supersaturation was ≥0.2%, the size-resolved chemical composition method was more accurate. As for the mixing state of the aerosol particles, in haze, heavy haze, and severe haze weather conditions CCN predictions based on the internal mixing assumption were robust, whereas for other weather conditions, predictions based on the external mixing assumption were more accurate. PMID:27075947

  2. Characterization and parameterization of aerosol cloud condensation nuclei activation under different pollution conditions

    NASA Astrophysics Data System (ADS)

    Che, H. C.; Zhang, X. Y.; Wang, Y. Q.; Zhang, L.; Shen, X. J.; Zhang, Y. M.; Ma, Q. L.; Sun, J. Y.; Zhang, Y. W.; Wang, T. T.

    2016-04-01

    To better understand the cloud condensation nuclei (CCN) activation capacity of aerosol particles in different pollution conditions, a long-term field experiment was carried out at a regional GAW (Global Atmosphere Watch) station in the Yangtze River Delta area of China. The homogeneity of aerosol particles was the highest in clean weather, with the highest active fraction of all the weather types. For pollution with the same visibility, the residual aerosol particles in higher relative humidity weather conditions were more externally mixed and heterogeneous, with a lower hygroscopic capacity. The hygroscopic capacity (κ) of organic aerosols can be classified into 0.1 and 0.2 in different weather types. The particles at ~150 nm were easily activated in haze weather conditions. For CCN predictions, the bulk chemical composition method was closer to observations at low supersaturations (≤0.1%), whereas when the supersaturation was ≥0.2%, the size-resolved chemical composition method was more accurate. As for the mixing state of the aerosol particles, in haze, heavy haze, and severe haze weather conditions CCN predictions based on the internal mixing assumption were robust, whereas for other weather conditions, predictions based on the external mixing assumption were more accurate.

  3. Characterization and parameterization of aerosol cloud condensation nuclei activation under different pollution conditions

    PubMed Central

    Che, H. C.; Zhang, X. Y.; Wang, Y. Q.; Zhang, L.; Shen, X. J.; Zhang, Y. M.; Ma, Q. L.; Sun, J. Y.; Zhang, Y. W.; Wang, T. T.

    2016-01-01

    To better understand the cloud condensation nuclei (CCN) activation capacity of aerosol particles in different pollution conditions, a long-term field experiment was carried out at a regional GAW (Global Atmosphere Watch) station in the Yangtze River Delta area of China. The homogeneity of aerosol particles was the highest in clean weather, with the highest active fraction of all the weather types. For pollution with the same visibility, the residual aerosol particles in higher relative humidity weather conditions were more externally mixed and heterogeneous, with a lower hygroscopic capacity. The hygroscopic capacity (κ) of organic aerosols can be classified into 0.1 and 0.2 in different weather types. The particles at ~150 nm were easily activated in haze weather conditions. For CCN predictions, the bulk chemical composition method was closer to observations at low supersaturations (≤0.1%), whereas when the supersaturation was ≥0.2%, the size-resolved chemical composition method was more accurate. As for the mixing state of the aerosol particles, in haze, heavy haze, and severe haze weather conditions CCN predictions based on the internal mixing assumption were robust, whereas for other weather conditions, predictions based on the external mixing assumption were more accurate. PMID:27075947

  4. Characterizing Aerosol Distributions and Optical Properties Using the NASA Langley High Spectral Resolution Lidar

    SciTech Connect

    Hostetler, Chris; Ferrare, Richard

    2013-02-14

    The objective of this project was to provide vertically and horizontally resolved data on aerosol optical properties to assess and ultimately improve how models represent these aerosol properties and their impacts on atmospheric radiation. The approach was to deploy the NASA Langley Airborne High Spectral Resolution Lidar (HSRL) and other synergistic remote sensors on DOE Atmospheric Science Research (ASR) sponsored airborne field campaigns and synergistic field campaigns sponsored by other agencies to remotely measure aerosol backscattering, extinction, and optical thickness profiles. Synergistic sensors included a nadir-viewing digital camera for context imagery, and, later in the project, the NASA Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP). The information from the remote sensing instruments was used to map the horizontal and vertical distribution of aerosol properties and type. The retrieved lidar parameters include profiles of aerosol extinction, backscatter, depolarization, and optical depth. Products produced in subsequent analyses included aerosol mixed layer height, aerosol type, and the partition of aerosol optical depth by type. The lidar products provided vertical context for in situ and remote sensing measurements from other airborne and ground-based platforms employed in the field campaigns and was used to assess the predictions of transport models. Also, the measurements provide a data base for future evaluation of techniques to combine active (lidar) and passive (polarimeter) measurements in advanced retrieval schemes to remotely characterize aerosol microphysical properties. The project was initiated as a 3-year project starting 1 January 2005. It was later awarded continuation funding for another 3 years (i.e., through 31 December 2010) followed by a 1-year no-cost extension (through 31 December 2011). This project supported logistical and flight costs of the NASA sensors on a dedicated aircraft, the subsequent

  5. A numerical testbed for the characterization and optimization of aerosol remote sensing

    NASA Astrophysics Data System (ADS)

    Wang, J.; Xu, X.; Ding, S.; Zeng, J.; Spurr, R. J.; Liu, X.; Chance, K.; Holben, B. N.; Dubovik, O.; Mishchenko, M. I.

    2013-12-01

    -Sparse kernels to compute the reflectance and the sensitivities to the kernel weighting factors; a linearized BPDF computes the angular polarized reflectance; (4) a linearized ocean surface model integrating the Cox-Munk glitter model with the chlorophyll-dependent water-leaving contribution; (5) a HITRAN-based gas absorption calculation of trace species cross sections (also linearized with respect to temperature and pressure); (6) the Levenberg-Marquardt inverse algorithm for cost-function minimization and optimal derivation of a posteriori solutions. In this presentation, we introduce our testbed and demonstrate applications to several sensor design and algorithm formulation concepts. This includes an evaluation of the use of polarization in the O2 A band for the retrieval of aerosol height information from space, and an assessment of the potential improvement in the characterization of aerosol scattering properties through the addition of more polarization channels to the AERONET sensors.

  6. Physicochemical Characterization of Lake Spray Aerosol Generated from Great Lakes Water Samples

    NASA Astrophysics Data System (ADS)

    Ault, A. P.; Axson, J. L.; May, N.; Pratt, K.

    2014-12-01

    Wave breaking across bodies of water releases particles into the air which can impact climate and human health. Similar to sea spray aerosols formed through marine wave breaking, freshwater lakes generate lake spray aerosol (LSA). LSA can impact climate directly through scattering/absorption and indirectly through cloud nucleation. In addition, these LSA are suggested to impact human health through inhalation of these particles during algal bloom periods characterized by toxic cyanobacteria. Few studies have been conducted to assess the physical and chemical properties of freshwater LSA. Herein, we discuss constructing a LSA generation system and preliminary physical and chemical characterization of aerosol generated from water samples collected at various sites across Lake Erie, Lake Huron, Lake Superior, and Lake Michigan. Information on aerosol size distributions, number concentrations, and chemical composition will be discussed as a function of lake water blue-green algae concentration, dissolved organic carbon concentration, temperature, conductivity, and dissolved oxygen concentration. These studies represent a first step towards evaluating the potential for LSA to impact climate and health in the Great Lakes region.

  7. Aerosol and Trace Gas Sources in Northern China: Changes in Concentrations Before and After the Official "Heating Season" Help Characterize Emissions From Coal-Fired Boilers

    NASA Astrophysics Data System (ADS)

    Li, C.; Marufu, L. T.; Dickerson, R. R.; Li, Z.; Stehr, J. W.; Chen, H.; Wang, P.

    2006-05-01

    In March 2005, as a part of the project EAST-AIRE (East Asian Study of Tropospheric Aerosols: An International Regional Experiment), in-situ measurements of trace gases and aerosol optical properties were made at Xianghe, a rural surface site about 70 km east-southeast, generally downwind, of Beijing metropolitan area. CO, SO2, NO/NOy, O3, aerosol absorption coefficient, and aerosol scattering coefficients were determined simultaneously using the University of Maryland light aircraft instrument package. Pollutant ratios have been calculated to characterize the emission sources around the site. A dramatic drop in the NOy/CO ratio found around March 13/14 suggesting a sudden shutoff of a large fraction of the high- temperature combustion sources in the region. This observed change in concentrations occurred simultaneously with the transition from "heating season" to "non-heating season" in Northern China. Over the course of just a few days (around March 15), all boilers used to provide heat for cities and towns in this region are shut down in accordance with a governmental guideline. Most of these boilers operate with coal, and by using ratios of NOy/CO, SO2/CO, aerosol scattering/CO, and aerosol absorption/CO during and after the "heating season", emissions from these small to medium sized coal-fired boilers can be characterized. Results indicate that these residential and small-scale industrial heaters are a major source of NOy and SO2. Besides elevating the regional atmospheric pollutant level, the trace gases and aerosols emitted also have potential effects in other aspects such as the biogeochemical cycle of N and the agricultural production in this region.

  8. The Saharan Aerosol Long-range Transport and Aerosol-Cloud Interaction Experiment (SALTRACE 2013) - An overview

    NASA Astrophysics Data System (ADS)

    Weinzierl, Bernadett; Ansmann, Albert; Reitebuch, Oliver; Freudenthaler, Volker; Müller, Thomas; Kandler, Konrad; Althausen, Dietrich; Chouza, Fernando; Dollner, Maximilian; Farrell, David; Groß, Silke; Heinold, Bernd; Kristensen, Thomas B.; Mayol-Bracero, Olga L.; Omar, Ali; Prospero, Joseph; Sauer, Daniel; Schäfler, Andreas; Toledano, Carlos; Tegen, Ina

    2015-04-01

    Saharan mineral dust is regularly transported over long distances impacting air quality, health, weather and climate thousands of kilometers downwind of the Sahara. During transport, the properties of mineral dust may be modified thereby changing the associated impact on the radiation budget. Although mineral dust is of key importance for the climate system many questions such as the change of the dust size distribution during long-range transport, the role of wet and dry removal mechanisms, and the complex interaction between mineral dust and clouds remain open. To investigate the aging and modification of Saharan mineral dust during long-range transport across the Atlantic Ocean, the Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE: http://www.pa.op.dlr.de/saltrace) was conducted in June/July 2013. SALTRACE was designed as a closure experiment combining ground-based lidar, in-situ and sun photometer instruments deployed on Cape Verde, Barbados and Puerto Rico, with airborne measurements of the DLR research aircraft Falcon, satellite observations and model simulations. During SALTRACE, mineral dust from five dust outbreaks was studied under different atmospheric conditions and a unique data set on the chemical, microphysical and optical properties of aged mineral dust was gathered. For the first time, Lagrangian sampling of a dust plume in the Cape Verde area on 17 June 2013 which was again measured with the same instrumentation on 21 and 22 June 2013 near Barbados was realized. Further highlights of SALTRACE include the formation and evolution of tropical storm Chantal in a dusty environment and the interaction of dust with mixed-phase clouds. In our presentation, we give an overview of the SALTRACE study, discuss the meteorological situation and the dust transport during SALTRACE and highlight selected results from SALTRACE.

  9. Aerosol hygroscopicity and cloud droplet activation of extracts of filters from biomass burning experiments

    NASA Astrophysics Data System (ADS)

    Carrico, Christian M.; Petters, Markus D.; Kreidenweis, Sonia M.; Collett, Jeffrey L.; Engling, Guenter; Malm, William C.

    2008-04-01

    In this laboratory closure study, we compare sub- and supersaturated water uptake properties for aerosol particles possessing a range of hygroscopicity. Measurements for water sub-saturated conditions used a hygroscopic tandem differential mobility analyzer (HTDMA). Simultaneously, measurements of particle critical supersaturation were conducted on the same sample stream with a continuous flow cloud condensation nuclei (CCN) counter. For these experiments, we used filter-collected samples of biomass smoke generated in the combustion of two common wildland fire fuels, western sagebrush and Alaskan duff core. Extractions of separate sections of the filter were performed using two solvents, ultrapure water and methanol. The extracts were subsequently atomized, producing aerosols having a range of hygroscopic responses. HTDMA and CCN measurements were fit to a single-parameter model of water uptake, in which the fit parameter is denoted κ, the hygroscopicity parameter. Here, for the four extracts we observed mean values of the hygroscopicity parameter of 0.06 < κ < 0.30, similar to the range found previously for numerous pure organic compounds. Particles generated from the aqueous extracts of the filters had consistently larger κ than methanol extracts, while western sagebrush extract aerosols κ exceeded those from Alaskan duff core. HTDMA- and CCN-derived values of κ for each experiment agreed within approximately 20%. Applicability of the κ-parameterization to other multicomponent aerosols relevant to the atmosphere remains to be tested.

  10. Characterization of submicron aerosols at a suburban site in central China

    NASA Astrophysics Data System (ADS)

    Wang, Qingqing; Zhao, Jian; Du, Wei; Ana, Godson; Wang, Zhenzhu; Sun, Lu; Wang, Yuying; Zhang, Fang; Li, Zhanqing; Ye, Xingnan; Sun, Yele

    2016-04-01

    We have characterized the chemical composition and sources of submicron aerosol (PM1) at a suburban site in Xinzhou in central China using an Aerosol Chemical Speciation Monitor from July 17 to September 5, 2014. The average (±1σ) PM1 concentration was 35.4 (±20.8) μg/m3 for the entire study period, indicating that Xinzhou was less polluted compared to the megacities in the North China Plain (NCP). The PM1 was mainly composed of organic aerosol and sulfate, on average accounting for 33.1% and 32.4%, respectively, followed by nitrate (14.4%) and ammonium (11.8%). Higher sulfate and lower nitrate contributions than those in megacities in the NCP elucidated an important emission source of coal combustion in central China. Three organic aerosol (OA) factors, i.e., hydrocarbon-like OA (HOA), semi-volatile oxygenated OA (SV-OOA) and low-volatility OOA (LV-OOA), were identified using positive matrix factorization. Secondary OA (=SV-OOA + LV-OOA) dominated OA, on average accounting for 82%, indicating that OA at the Xinzhou site was overall oxidized. We also observed relatively similar aerosol bulk composition and OA composition at low and high mass loading periods, and also from the different source areas, indicating that aerosol species were homogeneously distributed over a regional scale near the site for most of the time during this study. Slightly higher mass concentrations and sulfate contributions from the southern air masses were likely due to the transport from the polluted cities, such as Taiyuan to the south. In addition, the daily variation of PM1 in Xinzhou resembled that observed in Beijing, indicating that the wide-scale regional haze pollution often influences both the NCP and the central China.

  11. Characterization of Marine Aerosol for Assessment of Human Exposure to Brevetoxins

    PubMed Central

    Cheng, Yung Sung; Zhou, Yue; Irvin, Clinton M.; Pierce, Richard H.; Naar, Jerome; Backer, Lorraine C.; Fleming, Lora E.; Kirkpatrick, Barbara; Baden, Dan G.

    2005-01-01

    Red tides in the Gulf of Mexico are commonly formed by the fish-killing dinoflagellate Karenia brevis, which produces nine potent polyether brevetoxins (PbTxs). Brevetoxins can be transferred from water to air in wind-powered white-capped waves. Inhalation exposure to marine aerosol containing brevetoxins causes respiratory symptoms. We describe detailed characterization of aerosols during an epidemiologic study of occupational exposure to Florida red tide aerosol in terms of its concentration, toxin profile, and particle size distribution. This information is essential in understanding its source, assessing exposure to people, and estimating dose of inhaled aerosols. Environmental sampling confirmed the presence of brevetoxins in water and air during a red tide exposure period (September 2001) and lack of significant toxin levels in the water and air during an unexposed period May 2002). Water samples collected during a red tide bloom in 2001 showed moderate-to-high concentrations of K. brevis cells and PbTxs. The daily mean PbTx concentration in water samples ranged from 8 to 28 μg/L from 7 to 11 September 2001; the daily mean PbTx concentration in air samples ranged from 1.3 to 27 ng/m3. The daily aerosol concentration on the beach can be related to PbTx concentration in water, wind speed, and wind direction. Personal samples confirmed human exposure to red tide aerosols. The particle size distribution showed a mean aerodynamic diameter in the size range of 6–12 μm, with deposits mainly in the upper airways. The deposition pattern correlated with the observed increase of upper airway symptoms in healthy lifeguards during the exposure periods. PMID:15866777

  12. Physicochemical characterization of Capstone depleted uranium aerosols II: particle size distributions as a function of time.

    PubMed

    Cheng, Yung Sung; Kenoyer, Judson L; Guilmette, Raymond A; Parkhurst, Mary Ann

    2009-03-01

    The Capstone Depleted Uranium (DU) Aerosol Study, which generated and characterized aerosols containing DU from perforation of armored vehicles with large-caliber DU penetrators, incorporated a sampling protocol to evaluate particle size distributions. Aerosol particle size distribution is an important parameter that influences aerosol transport and deposition processes as well as the dosimetry of the inhaled particles. These aerosols were collected on cascade impactor substrates using a pre-established time sequence following the firing event to analyze the uranium concentration and particle size of the aerosols as a function of time. The impactor substrates were analyzed using proportional counting, and the derived uranium content of each served as input to the evaluation of particle size distributions. Activity median aerodynamic diameters (AMADs) of the particle size distributions were evaluated using unimodal and bimodal models. The particle size data from the impactor measurements were quite variable. Most size distributions measured in the test based on activity had bimodal size distributions with a small particle size mode in the range of between 0.2 and 1.2 microm and a large size mode between 2 and 15 microm. In general, the evolution of particle size over time showed an overall decrease of average particle size from AMADs of 5 to 10 microm shortly after perforation to around 1 microm at the end of the 2-h sampling period. The AMADs generally decreased over time because of settling. Additionally, the median diameter of the larger size mode decreased with time. These results were used to estimate the dosimetry of inhaled DU particles. PMID:19204485

  13. The Stratospheric Aerosol and Gas Experiment (SAGE III) on the International Space Station (ISS) Mission

    NASA Technical Reports Server (NTRS)

    Cisewski, Michael; Zawodny, Joseph; Gasbarre, Joseph; Eckman, Richard; Topiwala, Nandkishore; Rodriquez-Alvarez, Otilia; Cheek, Dianne; Hall, Steve

    2014-01-01

    The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) mission will provide the science community with high-vertical resolution and nearly global observations of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gas species in the stratosphere and upper-troposphere. SAGE III/ISS measurements will extend the long-term Stratospheric Aerosol Measurement (SAM) and SAGE data record begun in the 1970s. The multi-decadal SAGE ozone and aerosol data sets have undergone intense scrutiny and are considered the international standard for accuracy and stability. SAGE data have been used to monitor the effectiveness of the Montreal Protocol. Key objectives of the mission are to assess the state of the recovery in the distribution of ozone, to re-establish the aerosol measurements needed by both climate and ozone models, and to gain further insight into key processes contributing to ozone and aerosol variability. The space station mid-inclination orbit allows for a large range in latitude sampling and nearly continuous communications with payloads. The SAGE III instrument is the fifth in a series of instruments developed for monitoring atmospheric constituents with high vertical resolution. The SAGE III instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm. Science data is collected in solar occultation mode, lunar occultation mode, and limb scatter measurement mode. A SpaceX Falcon 9 launch vehicle will provide access to space. Mounted in the unpressurized section of the Dragon trunk, SAGE III will be robotically removed from the Dragon and installed on the space station. SAGE III/ISS will be mounted to the ExPRESS Logistics Carrier-4 (ELC-4) location on the starboard side of the station. To facilitate a nadir view from this location, a Nadir Viewing Platform (NVP) payload was developed which mounts between the carrier and the SAGE III Instrument Payload (IP).

  14. Molecular characterization of polar organosulfates in secondary organic aerosol from the green leaf volatile 3-Z-hexenal

    NASA Astrophysics Data System (ADS)

    Safi Shalamzari, Mohammad; Kahnt, Ariane; Wang, Wu; Vermeylen, Reinhilde; Kleindienst, Tadeusz; Lewandovski, Michael; Maenhaut, Willy; Claeys, Magda

    2014-05-01

    Much information is available about secondary organic aerosol (SOA) formation from terpenes, including mono- and sesquiterpenes, and isoprene. However, information about SOA formation from green leaf volatiles (GLVs), an important class of biogenic volatile organic compounds, which are emitted when plants are wounded or attacked by insects, is very scarce. In the present study, we provide evidence that 3-Z-hexenal is a potential precursor for SOA through formation of organosulfates. Organosulfate formation from 3-Z-hexenal was studied by conducting smog chamber photooxidation experiments in the presence of NO and acidic ammonium seed aerosol, where OH radicals were generated from the NOx mediated photochemical chain reactions. The focus of the study was on the structural characterization of products, i.e., organosulfates (OSs) with a molecular weight (MW) of 226, which are also present in ambient fine aerosol from a forested site (K puszta, Hungary) at a substantial relative abundance that is comparable to that of the MW 216 isoprene-related OSs. Polar OSs are of climatic relevance because of their capacity to increase the hydrophilic properties of aerosols and as such their cloud-condensation nuclei effects. Two different liquid chromatography (LC) techniques were employed to separate the polar OSs: the first technique uses a reversed-phase trifunctionally bonded C18 stationary phase, whereas the second one is based on ion-pairing C18 LC using dibutylammonium acetate as ion-pairing reagent. With regard to mass spectrometry (MS) techniques, use was made of high-resolution MS to determine the accurate mass (measured mass, 225.00809; elemental composition, C6H9O7S) as well as linear ion trap MS to obtain detailed structural information. The MW 226 OSs were structurally characterized as sulfated derivatives of 3,4-dihydroxyhex-2-enoic acid with the sulfate group positioned at C-3 or C-4. The formation of these OSs is explained through photooxidation in the gas phase

  15. [Characterization of photochemical smog chamber and initial experiments].

    PubMed

    Jia, Long; Xu, Yong-Fu; Shi, Yu-Zhen

    2011-02-01

    A self-made new indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosols has been introduced and characterized. The characterization experiments include the measurements of wall effects for reactive species and the determination of chamber dependent * OH radical sources by CO-NO(x) irradiation experiments. Preliminary ethene-NO(x) and benzene-NO(x) experiments were conducted as well. The results of characterization experiments show that the wall effects for O3 and NO2 in a new reactor are not obvious. Relative humidity has a great effect on the wall losses in the old reactor, especially for O3. In the old reactor, the rate constant for O3 wall losses is obtained to be 1.0 x 10(-5) s(-1) (RH = 5%) and 4.0 x10(-5) s(-1) (RH = 91%), whereas for NO2, it is 1.0 x 10(-6) s(-1) (RH = 5%) and 0.6 x 10(-6) s(-1) (RH = 75%). The value for k(NO2 --> HONO) determined by CO-NO(x) irradiation experiments is (4.2-5.2) x 10(-5) s(-1) and (2.3-2.5) x 10(-5) s(-1) at RH = 5% and RH 75% -77%, respectively. The average *OH concentration is estimated to be (2.1 +/- 0.4) x 10(6) molecules/cm3 by using a reaction rate coefficient of CO and * OH. The sensitivity of chamber dependent auxiliary reactions to the O3 formation is discussed. Results show that NO2 --> HONO has the greatest impact on the O3 formation during the initial stage, N2O5 + H2O --> 2HNO3 has a minus effect to maximum O3 concentration, and that the wall losses of both O3 and NO2 have little impact on the O3 formation. The results from the ethene-NO(x) and benzene-NO(x) experiments are in good agreement with those from the MCM simulation, which reflects that the facility for the study of the formation of secondary pollution of ozone and secondary organic aerosols is reliable. This demonstrates that our facility can be further used in the deep-going study of chemical processes in the atmosphere.

  16. Dust and polluted aerosol impacts on diazotrophy during a mesocosm experiment in the Eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Rahav, Eyal; Herut, Barak; Liu, Hongbin; Guo, Cui; Cheung, Isaac; Psarra, Stella; Lagaria, Anna; Tsiola, Anastasia; Tsagaraki, Tanya; Pitta, Paraskevi; Mulholland, Margaret; Berman-Frank, Ilana

    2014-05-01

    Atmospheric inputs of nutrients via dust and aerosols to the surface ocean layer are considered to contribute greatly to dinitrogen (N2) fixation and to primary productivity. N2 fixation rates in the Mediterranean Sea are typically low and the parameters limiting this process are still unclear. Addition of dust analogs to a mesocosm experiment in the Western Mediterranean Sea (DUNE) enhanced N2 fixation by 3 to 5 fold. However, in the Eastern Mediterranean Sea, an area highly exposed to Saharan dust and aerosol, the impact of these inputs on N2 fixation from onboard microcosm experiment are unclear and inconclusive. We examined the influence of Saharan dust (1.6 mg L-1) and polluted aerosol (1 mg L-1) additions on diazotroph populations and N2 fixation rates in nine 3 m3 mesocosms (MESOAQUA project) using the enriched seawater method of 15N uptake. The enrichments induced an immediate 2-4 fold increase in N2 fixation (measured from 6 to 48 h after enrichments). After 4 days, N2 fixation rates returned to their background level and no significant change was observed relative to the control mesocosms. The increase in N2 fixation rates were reflected in the differential composition of diazotrophs. Dust enrichment enhanced the abundance of the filamentous cyanobacterium Trichodesmium spp., while aerosol addition predominantly enhanced the presence of heterotrophic diazotrophs including Pseudomonas and Desulfovibrio. Our results indicate that sources of nutrients supplied via Saharan dust and polluted aerosol pulses to the stratified surface Eastern Mediterranean waters could increase the contribution of diazotrophs and N2 fixation in these ultraoligotrophic waters and impact productivity and biogeochemical cycling.

  17. Characterization of Highly Oxidized Molecules in Fresh and Aged Biogenic Secondary Organic Aerosol.

    PubMed

    Tu, Peijun; Hall, Wiley A; Johnston, Murray V

    2016-04-19

    In this work, highly oxidized multifunctional molecules (HOMs) in fresh and aged secondary organic aerosol (SOA) derived from biogenic precursors are characterized with high-resolution mass spectrometry. Fresh SOA was generated by mixing ozone with a biogenic precursor (β-pinene, limonene, α-pinene) in a flow tube reactor. Aging was performed by passing the fresh SOA through a photochemical reactor where it reacted with hydroxyl radicals. Although these aerosols were as a whole not highly oxidized, molecular analysis identified a significant number of HOMs embedded within it. HOMs in fresh SOA consisted mostly of monomers and dimers, which is consistent with condensation of extremely low-volatility organic compounds (ELVOCs) that have been detected in the gas phase in previous studies and linked to SOA particle formation. Aging caused an increase in the average number of carbon atoms per molecule of the HOMs, which is consistent with particle phase oxidation of (less oxidized) oligomers already existing in fresh SOA. HOMs having different combinations of oxygen-to-carbon ratio, hydrogen-to-carbon ratio and average carbon oxidation state are discussed and compared to low volatility oxygenated organic aerosol (LVOOA), which has been identified in ambient aerosol based on average elemental composition but not fully understood at a molecular level. For the biogenic precursors and experimental conditions studied, HOMs in fresh biogenic SOA have molecular formulas more closely resembling LVOOA than HOMs in aged SOA, suggesting that aging of biogenic SOA is not a good surrogate for ambient LVOOA. PMID:27000653

  18. Characterization and Cytotoxic Assessment of Ballistic Aerosol Particulates for Tungsten Alloy Penetrators into Steel Target Plates

    PubMed Central

    Machado, Brenda I.; Murr, Lawrence E.; Suro, Raquel M.; Gaytan, Sara M.; Ramirez, Diana A.; Garza, Kristine M.; Schuster, Brian E.

    2010-01-01

    The nature and constituents of ballistic aerosol created by kinetic energy penetrator rods of tungsten heavy alloys (W-Fe-Ni and W-Fe-Co) perforating steel target plates was characterized by scanning and transmission electron microscopy. These aerosol regimes, which can occur in closed, armored military vehicle penetration, are of concern for potential health effects, especially as a consequence of being inhaled. In a controlled volume containing 10 equispaced steel target plates, particulates were systematically collected onto special filters. Filter collections were examined by scanning and transmission electron microscopy (SEM and TEM) which included energy-dispersive (X-ray) spectrometry (EDS). Dark-field TEM identified a significant nanoparticle concentration while EDS in the SEM identified the propensity of mass fraction particulates to consist of Fe and FeO, representing target erosion and formation of an accumulating debris field. Direct exposure of human epithelial cells (A549), a model for lung tissue, to particulates (especially nanoparticulates) collected on individual filters demonstrated induction of rapid and global cell death to the extent that production of inflammatory cytokines was entirely inhibited. These observations along with comparisons of a wide range of other nanoparticulate species exhibiting cell death in A549 culture may suggest severe human toxicity potential for inhaled ballistic aerosol, but the complexity of the aerosol (particulate) mix has not yet allowed any particular chemical composition to be identified. PMID:20948926

  19. AATSR Single View Satellite Aerosol Retrievals Over the Persian Gulf During the 2004 United Arabic Emirates Unified Aerosol Experiment (UAE2)

    NASA Astrophysics Data System (ADS)

    Schoemaker, R. M.

    2006-12-01

    During the months of August and September 2004 the United Arabic Emirates Unified Aerosol Experiment (UAE2) mission took place in the marine and desert region of the United Arabic Emirates. One of the primary goals of the mission was to evaluate and improve scientific based satellite aerosol and ocean retrieval products. Important aspect was the calibration and validation of remote sensing systems in order to gain more insight in space-based retrievals over this part of the region. This paper contributes to part of the space-based mission objectives and governs the retrieval of atmospheric aerosol properties over water through data from the AATSR instrument on board the European ENVISAT satellite. At TNO Defence, Security and Safety the retrieval of aerosol properties from AATSR is performed by means of the dual view algorithm for application over land and the single view algorithm for application over ocean. Both algorithms have been merged into a fast and efficient algorithm that allows for near real-time processing and which is suitable for semi-operational use. Data from retrievals over water have been compared with ground-truth measurements from the AERONET sun photometers present for the three water sites in the Persian Gulf during the campaign. The properties retrieved are a) aerosol optical depth for the visible wavelengths of AATSR and b) the Ångström wavelength coefficient α as an indicator for the size distribution. Different aerosol types have been pre-modeled by means of AERONET phase function information, and saved as look-up tables for the retrieval procedure. By comparing the satellite retrieved information with the ground-truth data for each of the modeled aerosol type more insight in the retrieval procedure and in the aerosol make-up in this region is obtained.

  20. Raman lidar and sun photometer measurements of aerosols and water vapor during the ARM RCS experiment

    NASA Technical Reports Server (NTRS)

    Ferrare, R. A.; Whiteman, D. N.; Melfi, S. H.; Evans, K. D.; Holben, B. N.

    1995-01-01

    The first Atmospheric Radiation Measurement (ARM) Remote Cloud Study (RCS) Intensive Operations Period (IOP) was held during April 1994 at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma. This experiment was conducted to evaluate and calibrate state-of-the-art, ground based remote sensing instruments and to use the data acquired by these instruments to validate retrieval algorithms developed under the ARM program. These activities are part of an overall plan to assess general circulation model (GCM) parameterization research. Since radiation processes are one of the key areas included in this parameterization research, measurements of water vapor and aerosols are required because of the important roles these atmospheric constituents play in radiative transfer. Two instruments were deployed during this IOP to measure water vapor and aerosols and study their relationship. The NASA/Goddard Space Flight Center (GSFC) Scanning Raman Lidar (SRL) acquired water vapor and aerosol profile data during 15 nights of operations. The lidar acquired vertical profiles as well as nearly horizontal profiles directed near an instrumented 60 meter tower. Aerosol optical thickness, phase function, size distribution, and integrated water vapor were derived from measurements with a multiband automatic sun and sky scanning radiometer deployed at this site.

  1. Physical and chemical characterization of marine atmospheric aerosols over the North and South Pacific Oceans using single particle mass spectrometry

    NASA Astrophysics Data System (ADS)

    Furutani, H.; Jung, J.; Miura, K.; Uematsu, M.

    2010-12-01

    Physical and chemical properties of marine atmospheric aerosols were characterized and compared over the North and South Pacific Ocean during two trans-Pacific cruises (from Japan to Chile and Australia to Japan) during the period of January-June 2009, which cover broad region of Pacific Ocean from 40°N to 55°S and 140°E to 70°W. The measured parameters of aerosol properties were single particle size-resolved chemical composition (D = 100 ~ 1500 nm), cloud condensation nuclei (CCN) and condensation nuclei (CN) concentrations, size distribution from 10 nm to 5 μm, total aerosol nitrate and sulfate concentrations, and filter-based chemical composition. Trace gas concentrations of O3 and CO were also measured to aid air parcel categorization during the cruises. Reflecting larger anthropogenic emission in the Northern Hemisphere, pronounced concentration gradient between the North and South Pacific Ocean was observed for aerosol nitrate, CO, and O3. Aerosol sulfate also showed a similar concentration drop in the equatorial region, relatively higher sulfate concentration was observed in 30°S-40°S and 55°S regions, which was associated with increased aerosol methanesulfonic acid (MSA) concentration but little increase in local marine chlorophyll concentration, suggesting contribution of long-range transported marine biogenic sulfur from the high primary production area over the South Pacific high latitude region. Aerosol chemical classification by single particle chemical analysis revealed that certain aerosol types, such as biomass burning, elemental carbon, and elemental/organic carbon mixed type, were mainly observed in the North Pacific region, while several specific organic aerosol types with abundant aged organic and disulfur composition were identified in the South Pacific region. Further comparison of aerosol properties, aerosol sources, and atmospheric aerosol processing in the North and South Pacific Oceans will be discussed.

  2. Characterization of aerosol particles from grass mowing by joint deployment of ToF-AMS and ATOFMS instruments

    NASA Astrophysics Data System (ADS)

    Drewnick, Frank; Dall'Osto, Manuel; Harrison, Roy

    During a measurement campaign at a semi-urban/industrial site a grass-cutting event was observed, when the lawn in the immediate surrounding of the measurement site was mowed. Using a wide variety of state-of-the-art aerosol measurement technology allowed a broad characterization of the aerosol generated by the lawn mowing. The instrumentation included two on-line aerosol mass spectrometers: an Aerodyne Time-of-Flight Aerosol Mass Spectrometer (ToF-AMS) and a TSI Aerosol Time-of-Flight Mass Spectrometer (ATOFMS); in addition, a selection of on-line aerosol concentration and size distribution instruments (OPC, APS, SMPS, CPC, FDMS-TEOM, MAAP) was deployed. From comparison of background aerosol measurements during most of the day with the aerosol measured during the lawn mowing, the grass cutting was found to generate mainly two different types of aerosol particles: an intense ultrafine particle mode (1 h average: 4 μg m -3) of almost pure hydrocarbon-like organics and a distinct particle mode in the upper sub-micrometer size range containing particles with potassium and nitrogen-organic compounds. The ultrafine particles are probably lubricating oil particles from the lawn mower exhaust; the larger particles are swirled-up plant debris particles from the mowing process. While these particle types were identified in the data from the two mass spectrometers, the on-line aerosol concentration and size distribution data support these findings. The results presented here show that the combination of quantitative aerosol particle ensemble mass spectrometry (ToF-AMS) and single particle mass spectrometry (ATOFMS) provides much deeper insights into the nature of the aerosol properties than each of the instruments could do alone. Therefore a combined deployment of both types of instruments is strongly recommended.

  3. Development and characterization of an aircraft aerosol time-of-flight mass spectrometer.

    PubMed

    Pratt, Kerri A; Mayer, Joseph E; Holecek, John C; Moffet, Ryan C; Sanchez, Rene O; Rebotier, Thomas P; Furutani, Hiroshi; Gonin, Marc; Fuhrer, Katrin; Su, Yongxuan; Guazzotti, Sergio; Prather, Kimberly A

    2009-03-01

    Vertical and horizontal profiles of atmospheric aerosols are necessary for understanding the impact of air pollution on regional and global climate. To gain further insight into the size-resolved chemistry of individual atmospheric particles, a smaller aerosol time-of-flight mass spectrometer (ATOFMS) with increased data acquisition capabilities was developed for aircraft-based studies. Compared to previous ATOFMS systems, the new instrument has a faster data acquisition rate with improved ion transmission and mass resolution, as well as reduced physical size and power consumption, all required advances for use in aircraft studies. In addition, real-time source apportionment software allows the immediate identification and classification of individual particles to guide sampling decisions while in the field. The aircraft (A)-ATOFMS was field-tested on the ground during the Study of Organic Aerosols in Riverside, CA (SOAR) and aboard an aircraft during the Ice in Clouds Experiment-Layer Clouds (ICE-L). Initial results from ICE-L represent the first reported aircraft-based single-particle dual-polarity mass spectrometry measurements and provide an increased understanding of particle mixing state as a function of altitude. Improved ion transmission allows for the first single-particle detection of species out to approximately m/z 2000, an important mass range for the detection of biological aerosols and oligomeric species. In addition, high time resolution measurements of single-particle mixing state are demonstrated and shown to be important for airborne studies where particle concentrations and chemistry vary rapidly.

  4. Spent fuel sabotage test program, characterization of aerosol dispersal : technical review and analysis supplement.

    SciTech Connect

    Durbin, Samuel G.; Lindgren, Eric Richard

    2009-07-01

    This project seeks to provide vital data required to assess the consequences of a terrorist attack on a spent fuel transportation cask. One such attack scenario involves the use of conical shaped charges (CSC), which are capable of damaging a spent fuel transportation cask. In the event of such an attack, the amount of radioactivity that may be released as respirable aerosols is not known with great certainty. Research to date has focused on measuring the aerosol release from single short surrogate fuel rodlets subjected to attack by a small CSC device in various aerosol chamber designs. The last series of three experiments tested surrogate fuel rodlets made with depleted uranium oxide ceramic pellets in a specially designed double chamber aerosol containment apparatus. This robust testing apparatus was designed to prevent any radioactive release and allow high level radioactive waste disposal of the entire apparatus following testing of actual spent fuel rodlets as proposed. DOE and Sandia reviews of the project to date identified a number of issues. The purpose of this supplemental report is to address and document the DOE review comments and to resolve the issues identified in the Sandia technical review.

  5. Direct containment heating and aerosol generation during high pressure melt ejection experiments

    SciTech Connect

    Tarvell, W.W.; Brockmann, J.E.; Washington, K.E.; Pilch, M.; Marx, K.D.

    1988-01-01

    Containment loading in the form of increased atmosphere pressure and temperature during a severe reactor accident can result from the expulsion of core debris from the reactor cavity. This increase in the pressure and temperature can be accompanied by an aerosol source term that may have enhanced compositions of the more volatile radionuclide. Large scale experiments have been conducted in the Surtsey facility at Sandia National Laboratories to study the energy exchange processes and the generation of aerosols. Test results are reported here and compared to analytical predictions made by an experiment analysis code and a containment response model. The experiments show that the energy exchange and aerosol generation processes are greatly affected by trapping of the debris on the surfaces of the test chamber. Good agreement is achieved between experimental data and model predictions by incorporating models for debris trapping on surfaces and the formation of the retained material into drops that fall through the chamber at late time. 23 refs., 11 figs., 4 tabs.

  6. Toward Developing a New Occupational Exposure Metric Approach for Characterization of Diesel Aerosols

    PubMed Central

    Cauda, Emanuele G.; Ku, Bon Ki; Miller, Arthur L.; Barone, Teresa L.

    2015-01-01

    The extensive use of diesel-powered equipment in mines makes the exposure to diesel aerosols a serious occupational issue. The exposure metric currently used in U.S. underground noncoal mines is based on the measurement of total carbon (TC) and elemental carbon (EC) mass concentration in the air. Recent toxicological evidence suggests that the measurement of mass concentration is not sufficient to correlate ultrafine aerosol exposure with health effects. This urges the evaluation of alternative measurements. In this study, the current exposure metric and two additional metrics, the surface area and the total number concentration, were evaluated by conducting simultaneous measurements of diesel ultrafine aerosols in a laboratory setting. The results showed that the surface area and total number concentration of the particles per unit of mass varied substantially with the engine operating condition. The specific surface area (SSA) and specific number concentration (SNC) normalized with TC varied two and five times, respectively. This implies that miners, whose exposure is measured only as TC, might be exposed to an unknown variable number concentration of diesel particles and commensurate particle surface area. Taken separately, mass, surface area, and number concentration did not completely characterize the aerosols. A comprehensive assessment of diesel aerosol exposure should include all of these elements, but the use of laboratory instruments in underground mines is generally impracticable. The article proposes a new approach to solve this problem. Using SSA and SNC calculated from field-type measurements, the evaluation of additional physical properties can be obtained by using the proposed approach. PMID:26361400

  7. Combining data from lidar and in situ instruments to characterize the vertical structure of aerosol optical properties

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Turco, R. P.; Pueschel, R. F.; Browell, E. V.; Grant, W. B.

    1998-01-01

    Over the last decade, the quantification of tropospheric aerosol abundance, composition and radiative impacts has become an important research endeavor. For the most part, the interest in tropospheric aerosols is derived from questions related to the global and local (instantaneous) radiative forcing of climate due to these aerosols. One approach is to study local forcing under well-defined conditions, and to extrapolate such results to global scales. To estimate local aerosol forcing, appropriate radiative transfer models can be employed (e.g., the Fu-Liou radiative transfer code, [Fu and Liou, 1993]). In general, such models require information on derived aerosol properties [Toon, 1994]; namely the aerosol optical depth, single-scattering albedo, and asymmetry factor (phase function), all of which appear in the equations of radiative transfer. In this paper, we report on a method that utilizes lidar data and in situ aerosol size distribution measurements to deduce the vertical structure of the aerosol complex index of refraction in the near IR, thus identifying the aerosol type. Together with aerosol size distributions obtained in situ, the aerosol refractive index can be used to calculate the necessary derived aerosol properties. The data analyzed here were collected during NASA's PEM West-B (Pacific Exploratory Mission) experiment, which took place in February/March 1994. The platform for the measurements was the NASA DC-8 aircraft. The primary goal of the PEM West missions [Browell et al., 1996] was the assessment of potential anthropogenic perturbations of the chemistry in the Pacific Basin troposphere. For this purpose the timing of PEM West-B corresponded to the seasonal peak in transport from the Asian continent into the Pacific basin [Merrill et al., in press]. This period normally occurs during Northern Hemisphere spring, when the Japan jet is well developed.

  8. Molecular Characterization of Biomass Burning Aerosols Using High Resolution Mass Spectrometry

    SciTech Connect

    Smith, Jeffrey S.; Laskin, Alexander; Laskin, Julia

    2009-02-13

    Chemical characterizations of atmospheric aerosols is a serious analytical challenge because of the complexity of particulate matter analyte composed of a large number of compounds with a wide range of molecular structures, physico-chemical properties, and reactivity. In this study chemical composition of biomass burning organic aerosol (BBOA) samples is characterized by high resolution electrospray ionization mass spectrometry (ESI/MS). Accurate mass measurement combined with Kendrick analysis allowed us to assign elemental composition for hundreds of compounds in the range of m/z values of 50-1000. ESI/MS spectra of different BBOA samples contain a variety of distinct, sample specific, characteristic peaks that can be used as unique markers for different types of biofuels. Our results indicate that a significant number of high-MW organic compounds in BBOA samples are highly oxidized polar species that can be efficiently detected using ESI/MS but are difficult to observe using the conventional GCMS analysis of aerosol samples. The average O:C ratios obtained for each of the BBOA samples studied in this work are in a strikingly good agreement with the previously reported values obtained using STXM/NEXAFS. The degree of unsaturation of detected organic compounds shows a clear decrease with increase in the molecular weight of the anyalyte molecules. The decrease is particularly pronounced for the samples containing a large number of CH2-based homologous series.

  9. Temporal and spatial long-term characterizations of aerosol optical depth and its radiative effects over Spain

    NASA Astrophysics Data System (ADS)

    Cachorro, Victoria E.; Toledano, Carlos; Joao Costa, Maria; Anton, Manuel; Mateos, D.; Alados-Arboledas, L.; Sorribas, M.; Baldasano, Jose M.

    A better understanding of the aerosol radiative properties is a crucial challenge for climate change studies. This study aims to provide a complete characterization of aerosol radiative effects in different spectral ranges within the shortwave (SW) solar spectrum. Six long-term datasets of aerosol properties of AERONET (AErosol RObotic NETwork) over the Iberian Peninsula are analyzed. The aerosol load over the Iberian Peninsula shows a decrease trend between 2004 and 2012 (-0.04 per unit of aerosol optical depth per decade). Continental aerosols are identified as the main type over the peninsula, although desert dust events are phenomena registered at the six sites with a clear South-North gradient, which modulates the aerosol climatology over the analyzed area. Aerosol data are used as input in the libRadtran model to simulate ultraviolet (UV), visible (VIS), near-infrared (NIR), and SW radiation. Then, the aerosol radiative effect (ARE) and aerosol forcing efficiency (AFE) can be evaluated. ARE values at the six stations differ because of the different aerosol types over each station. Considering the whole Iberian Peninsula, ARE is in the ranges: -1.1 < ARE _{UV} < -0.7 W m (-2) , -5.7 < ARE _{VIS} < -3.8 W m (-2) , -2.8 < ARE _{NIR} < -1.7 W m (-2) , and -9.5 < ARE _{SW} < -6.1 W m (-2) . The four variables show positive statistically significant trends between 2004 and 2012 (e.g., ARE _{SW} increased +3.6 W m (-2) per decade). I.e., a reduction of ARE on solar radiation at the surface is observed in this period. The intra-annual ARE cycle exhibits larger values during the spring and summer months when the likelihood of high aerosol loading over the Iberian Peninsula increases. Finally, AFE exhibits a clear dependence on single scattering albedo and a weaker one on Ångström exponent. AFE is larger (in absolute value) for small and absorbing particles. The contributions of the UV, VIS, and NIR ranges to the SW efficiency vary with the aerosol types. Conditions

  10. Design and characterization of a smog chamber for studying gas-phase chemical mechanisms and aerosol chemistry

    NASA Astrophysics Data System (ADS)

    Wang, X.; Liu, T.; Bernard, F.; Ding, X.; Wen, S.; Zhang, Y.; Zhang, Z.; He, Q.; Lü, S.; Chen, J.; Saunders, S.; Yu, J.

    2013-08-01

    We describe here characterization of a new state-of-the-art smog chamber facility for studying atmospheric gas phase and aerosol chemistry. The chamber consists of a 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor suspended in a temperature-controlled enclosure equipped with two banks of black lamps as the light source. Temperature can be set in the range from -10 °C to 40 °C at accuracy of ±1 °C as measured by eight temperature sensors inside the enclosure and one just inside the reactor. Matrix air can be purified with NMHCs < 0.5 ppb, NOx/O3/carbonyls < 1 ppb and particles < 1 cmexperiments. The results indicate that this new smog chamber can provide high quality data for mechanism evaluation. Results of α-pinene dark ozonolysis experiments revealed SOA yields comparable to those from other chamber studies, and the two-product model gives a good fit for the yield data obtained in this work. Characterization experiments demonstrate that our GIG-CAS smog chamber facility can be used to provide valuable data for gas-phase mechanisms and aerosol chemistry.

  11. On the Stratospheric Aerosol and Gas Experiment III on the International Space Station

    NASA Technical Reports Server (NTRS)

    Hernandez, Gloria; Zawodny, Joseph M.; Cisewski, Michael S.; Thornton, Brooke M.; Panetta, Andrew D,; Roell, Marilee M.; Vernier, Jean-Paul

    2014-01-01

    The Stratospheric Aerosol and Gas Experiment III on International Space Station (SAGE3/ISS) is anticipated to be delivered to Cape Canaveral in the spring of 2015. This is the fourth generation, fifth instrument, of visible/near-IR solar occultation instruments operated by the National Aeronautics and Space Agency (NASA) to investigate the Earth's upper atmosphere. The instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. The SAGE3/ISS validation program will be based upon internal consistency of the measurements, detailed analysis of the retrieval algorithm, and comparisons with independent correlative measurements. The Instrument Payload (IP), mission architecture, and major challenges are also discussed.

  12. The Landes experiment: Biosphere-atmosphere exchanges of ozone and aerosol particles above a pine forest

    SciTech Connect

    Lamaud, E.; Labatut, A.; Lopez, A.; Fontan, J.; Druilhet, A.; Brunet, Y.

    1994-08-20

    An experiment to measure the transfer of trace gases in the lower atmosphere was performed in the forested area of {open_quotes} Les Landes {close_quotes} in southwestern France. This region is one of the largest remaining forests in western Europe, and consists predominantly of resinous trees (maritime pines). This experiment involved emission measurements of chemically reactive species, measurement methodologies, mechanisms for flux and the influence of these emissions on boundary layer chemistry. This paper presents preliminary results on the dry deposition of ozone and aerosol particles in the boundary layer. 28 refs., 15 figs.

  13. Aerosols, clouds, and precipitation in the North Atlantic trades observed during the Barbados aerosol cloud experiment - Part 1: Distributions and variability

    NASA Astrophysics Data System (ADS)

    Jung, Eunsil; Albrecht, Bruce A.; Feingold, Graham; Jonsson, Haflidi H.; Chuang, Patrick; Donaher, Shaunna L.

    2016-07-01

    Shallow marine cumulus clouds are by far the most frequently observed cloud type over the Earth's oceans; but they are poorly understood and have not been investigated as extensively as stratocumulus clouds. This study describes and discusses the properties and variations of aerosol, cloud, and precipitation associated with shallow marine cumulus clouds observed in the North Atlantic trades during a field campaign (Barbados Aerosol Cloud Experiment- BACEX, March-April 2010), which took place off Barbados where African dust periodically affects the region. The principal observing platform was the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter (TO) research aircraft, which was equipped with standard meteorological instruments, a zenith pointing cloud radar and probes that measured aerosol, cloud, and precipitation characteristics.The temporal variation and vertical distribution of aerosols observed from the 15 flights, which included the most intense African dust event during all of 2010 in Barbados, showed a wide range of aerosol conditions. During dusty periods, aerosol concentrations increased substantially in the size range between 0.5 and 10 µm (diameter), particles that are large enough to be effective giant cloud condensation nuclei (CCN). The 10-day back trajectories showed three distinct air masses with distinct vertical structures associated with air masses originating in the Atlantic (typical maritime air mass with relatively low aerosol concentrations in the marine boundary layer), Africa (Saharan air layer), and mid-latitudes (continental pollution plumes). Despite the large differences in the total mass loading and the origin of the aerosols, the overall shapes of the aerosol particle size distributions were consistent, with the exception of the transition period.The TO was able to sample many clouds at various phases of growth. Maximum cloud depth observed was less than ˜ 3 km, while most clouds were less than 1 km

  14. Aerosol characterization over Sundarban mangrove forest at the north-east coast of Bay of Bengal, India

    NASA Astrophysics Data System (ADS)

    Chatterjee, Abhijit; Das, Sanat Kumar; Sarkar, Chirantan; Ghosh, Sanjay; Raha, Sibaji; Singh, Soumendra; Roy, Arindam

    2016-07-01

    A comprehensive study was conducted on chemical characterization of size segregated and cumulative aerosols during winter, 2015 and summer 2016 over a remote mangrove forest at Sundarban at the north-east coast of Bay of Bengal. Aerosols originated from the surf zone at the land-ocean boundary of Sundarban mangrove forest and aerosols advected from Kolkata and other metropolitan and urban cities at Indo-Gangetic Plain were characterized in terms of major water soluble inorganic species. Attempt was made to investigate the combined effect of locally generated sea-salt and advected anthropogenic aerosols could change the pristine marine character at this region during the above mentioned periods. Significant chloride depletion from sea-salt aerosols was observed in coarse and ultrafine mode compared to fine mode in winter whereas reverse trend was observed during summer. On an average the chloride to sodium ratio in PM10 aerosol was found to be around 0.6 which was much lower than that in sea-water. It was observed that non-sea-sulphate and nitrate aerosols were the major species depleting chloride from sea-salt aerosols. This supported the interaction between fresh marine and polluted anthropogenic aerosols. The average concentration of PM10 aerosols was 64 μg m-3 in winter and 89 μg m-3 in summer. Major water soluble ionic species were used for the source apportionment of aerosol during the two seasons. On an average it was observed that 60-70 % of total PM10 aerosols were constituted by the major water soluble ionic species. Emission flux and deposition flux of aerosols were also studied over this remote forest region. It was also observed that anthropogenic ionic species were mostly accumulated in the ultrafine and fine mode region both during winter and summer. On the other hand sea-salt species were mostly accumulated in the coarse mode region. Sulphate aerosol showed bimodal distribution with prominent peaks both at ultrafine/fine and coarse mode region

  15. Aerosol Radiative Effects: Expected Variations in Optical Depth Spectra and Climate Forcing, with Implications for Closure Experiment Strategies

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.; Stowe, L. L.; Hobbs, P. V.; Podolske, James R. (Technical Monitor)

    1995-01-01

    We examine measurement strategies for reducing uncertainties in aerosol direct radiative forcing by focused experiments that combine surface, air, and space measurements. Particularly emphasized are closure experiments, which test the degree of agreement among different measurements and calculations of aerosol properties and radiative effects. By combining results from previous measurements of large-scale smokes, volcanic aerosols, and anthropogenic aerosols with models of aerosol evolution, we estimate the spatial and temporal variability in optical depth spectra to be expected in the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX, planned for summer 1996 off the Eastern U.S. seaboard). In particular, we examine the expected changes in the wavelength dependence of optical depth as particles evolve through nucleation, growth by condensation and coagulation, and removal via sedimentation. We then calculate the expected radiative climate forcing (i.e. change in net radiative flux) for typical expected aerosols and measurement conditions (e.g. solar elevations, surface albedos, radiometer altitudes). These calculations use new expressions for flux and albedo changes, which account not only for aerosol absorption, but also for instantaneous solar elevation angles and the dependence of surface albedo on solar elevation. These factors, which are usually ignored or averaged in calculations of global aerosol effects, can have a strong influence on fluxes measured in closure experiments, and hence must be accounted for in calculations if closure is to be convincingly tested. We compare the expected measurement signal to measurement uncertainties expected for various techniques in various conditions. Thereby we derive recommendations for measurement strategies that combine surface, airborne, and spaceborne measurements.

  16. Chemical Characterization of Submicron Aerosol Particles in São Paulo, Brazil

    NASA Astrophysics Data System (ADS)

    Ferreira De Brito, J.; Rizzo, L. V.; Godoy, J.; Godoy, M. L.; de Assunção, J. V.; Alves, N. D.; Artaxo, P.

    2013-12-01

    Megacities, large urban conglomerates with a population of 10 million or more inhabitants, are increasingly receiving attention as strong pollution hotspots with significant global impact. The emissions from such large centers in both the developed and developing parts of the world are strongly impacted by the transportation sector. The São Paulo Metropolitan Area (SPMA), located in the Southeast of Brazil, is a megacity with a population of 18 million people and 7 million vehicles, many of which fuelled by a considerably amount of anhydrous ethanol. Such fleet is considered a unique case of large scale biofuel usage worldwide. Despite the large impact on human health and atmospheric chemistry/dynamics, many uncertainties are found in terms of gas and particulate matter emissions from vehicles and their atmospheric reactivity, e.g. secondary organic aerosol formation. In order to better understand aerosol life cycle on such environment, a suite of instruments for gas and particulate matter characterization has been deployed in two sampling sites within the SPMA, including an Aerosol Chemical Speciation Monitor (ACSM). The instrumentation was deployed at the rooftop of a 45m high building in the University of São Paulo during winter/spring 2012. The site is located roughly 6km downwind of the city center with little influence from local sources. The second site is located in a downtown area, sampling at the top floor of the Public Health Faculty, approximately 10m above ground. The instrumentation was deployed at the Downtown site during summer/fall 2013. The average non-refractory submicron aerosol concentration at the University site was 6.7 μg m-3, being organics the most abundant specie (70%), followed by NO3 (12%), NH4 (8%), SO4 (8%) and Chl (2%). At the Downtown site, average aerosol concentration was 15.1 μg m-3, with Organics composing 65% of the mass, followed by NH4 (12%), NO3 (11%), SO4 (11%) and Chl (1%). The analysis of specific fragmentation

  17. Aerosol Physical and Chemical Properties Before and After the Manaus Plume in the GoAmazon2014 Experiment

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Barbosa, H. M.; Ferreira De Brito, J.; Wurm, F.; Holanda, B. A.; Carbone, S.; Arana, A.; Cirino, G. G.; Souza, R. A. F. D.; Rizzo, L. V.; Martin, S. T.; Andreae, M. O.; Holben, B. N.; Schafer, J.

    2014-12-01

    As part of the GoAmazon2014 experiment, several aerosol and trace gas monitoring stations are being operated for at least one year before and after the Manaus plume. Three sites are being operated in pristine conditions, with atmospheric properties under natural biogenic conditions. These three sites called T0 are: ATTO (Amazon Tall Tower Observatory), ZF2 ecological research site and a third site called EMBRAPA. After the air masses are exposed to the Manaus plume, one site (called T2) is being operated right on the opposite side of the Negro River under the direct influence of the Manaus plume at 5 Km downwind of Manaus. Finally, at about 150 Km downwind of Manaus is the T3 Manacapuru site. Aerosol chemical composition is being analyzed using filters for fine (PM2.5) and coarse mode aerosol as well as three Aerodyne ACSM (Aerosol Chemical Speciation Monitors) instruments. Aerosol absorption is being studied with several aethalometers and MAAP (Multi Angle Absorption Photometers). Aerosol light scattering are being measured at several wavelengths using nephelometers. Aerosol size distribution is determined using scanning mobility particle sizers. The aerosol column is measures using AERONET sunphotometers before and after the Manaus plume, as well as several Lidar systems. The three sites before the Manaus plume show remarkable similar variability in aerosol concentrations and optical properties. This pattern is very different at the T2 site, with large aerosol concentrations enhancing aerosol absorption and scattering significantly. The aerosol is very oxidized before being exposed to the Manaus plume, and this pattern changes significantly for T2 and T3 sites, with a much higher presence of less oxidized aerosol. Typical ozone concentrations at mid-day before Manaus plume is a low 10-12 ppb, value that changes to 50-70 ppb for air masses suffering the influence of Manaus plume. A detailed comparison of aerosol characteristics and composition for the several

  18. Organic compounds in urban aerosols from Gent, Belgium: Characterization, sources, and seasonal differences

    NASA Astrophysics Data System (ADS)

    KubáTová, Alena; Vermeylen, Reinhilde; Claeys, Magda; Cafmeyer, Jan; Maenhaut, Willy

    2002-11-01

    About 100 individual organic compounds were determined in urban aerosols collected at Gent, Belgium. The compounds were identified by gas chromatography-mass spectrometry, and quantitative data were obtained by gas chromatography-flame ionization detection. Measurements of the particulate mass and of organic and elemental carbon mass were also made. Aerosol samples from a winter and a summer campaign were analyzed in order to examine seasonal differences. The major part of the extractable and elutable organic carbon in both winter and summer aerosols was found to correspond to an unresolved complex mixture that is typical for car exhaust. The prevailing resolved organic compounds in both seasons were n-alkanes and fatty acids, but the distribution patterns of individual components within each class showed seasonal differences. The n-alkane pattern for summer aerosols was clearly affected by emissions from the vegetation, while that of fatty acids revealed a lower relative abundance of unsaturated fatty acids in summer than winter that can be related to more extensive atmospheric oxidation of unsaturated fatty acids during summer. Concentrations of dicarboxylic acids and related products that are believed to be oxidation products of hydrocarbons and fatty acids were highest in summer aerosols. Some individual compounds in the latter class could only be detected in summer samples and showed the highest concentrations on hot summer days that were characterized by maximum temperatures above 25°C and increased ozone concentrations. The latter compounds included novel, recently identified glutaric acid derivatives, namely, 3-isopropyl and 3-acetyl pentanedioic acid, likely originating from atmospheric oxidation of reactive monoterpene or sesquiterpene precursors that still need to be identified. Several compounds were found that are markers of wood combustion, including diterpenoic acids, lignin pyrolysis products, and levoglucosan. The quantitative results obtained for

  19. Design and application of a new modular adapter for laser diffraction characterization of inhalation aerosols.

    PubMed

    de Boer, A H; Gjaltema, D; Hagedoorn, P; Schaller, M; Witt, W; Frijlink, H W

    2002-12-01

    An inhaler adapter has been designed for the characterization of the aerosol clouds from medical aerosol generators such as nebulizers, dry powder inhalers (dpis) and metered dose inhalers (mdis) with laser diffraction technology. The adapter has a pre-separator, for separation of large particles (i.e. carrier crystals) from the aerosol cloud before it is exposed to the laser beam. It also has a fine particle collector for measuring the emitted mass fraction of fines by chemical detection methods after laser diffraction sizing. The closed system enables flow control through the aerosol generators and all test conditions, including ambient temperature and relative humidity, are automatically recorded. Counter flows minimize particle deposition onto the two windows for the laser beam, which make successive measurements without cleaning of these windows possible. The adapter has successfully been tested for nebulizers, mdis and dpis. In a comparative study with ten nebulizers it was found that these devices differ considerably in droplet size (distribution) of the aerosol cloud for the same 10% aqueous tobramycin solution (volume median diameters ranging from 1.25 to 3.25 microm) when they are used under the conditions recommended by the manufacturers. The droplet size distribution generated by the Sidestream (with PortaNeb compressor) is very constant during nebulization until dry running of the device. Comparative testing of dpis containing spherical pellet type of formulations for the drug (e.g. the AstraZeneca Turbuhaler) with the adapter is fast and simple. But also formulations containing larger carrier material could successfully be measured. Disintegration efficiency of a test inhaler with carrier retainment (acting as a pre-separator) could be measured quite accurately both for a colistin sulfate formulation with 16.7% of a lactose fraction 106-150 microm and for a budesonide formulation with a carrier mixture of Pharmatose 325 and 150 M. Therefore, it is

  20. Molecular Characterization of Marine Organic Aerosols Collected during a Round-the-World Cruise

    NASA Astrophysics Data System (ADS)

    Fu, P.; Kawamura, K.; Miura, K.

    2010-12-01

    Total suspended particles (TSP) were collected on board the R/V Hakuho Maru during a round-the-world cruise (KH89-2) and were characterized for organic molecular compositions using solvent extraction/derivatization and gas chromatography/mass spectrometry technique. More than 140 organic species were detected in the marine aerosols and were grouped into 11 organic compound classes, including aliphatic lipids, anhydrosugars and sugar alcohols, lignin/resin acids, sterols, hopanes, polycyclic aromatic hydrocarbons, hydroxy-/polyacids, aromatic acids, as well as secondary organic aerosol (SOA) tracers from the photooxidation of biogenic volatile organic compounds. Concentrations of total quantified organics ranged from 0.94 to 98 ng m-3 (average 31 ng m-3) with higher concentrations in coastal regions (California Coast, South China Sea, and Western North Pacific) than in open marine areas (North Pacific and North Atlantic), suggesting that long-range atmospheric transport from the continents is the main source of marine organic aerosols. Isoprene SOA tracers, i.e., 2-methylglyceric acid, C5-alkene triols and 2-methyltetrols, were detected in all the samples (0.11-22 ng m-3, average 3.6 ng m-3) with higher concentrations in the tropical regions. They accounted for 0.48-29% of the total identified organics. Organic compounds were further categorized into several groups to clarify their sources. In the North Pacific and North Atlantic, secondary oxidation products (30-31%), fossil fuel combustion products (27-28%), as well as marine natural emissions (22-34%) were found as major contributors to the marine aerosols. In California Coast, North Indian Ocean and South China Sea, secondary oxidation products can contribute 44-55% of the total identified organics, followed by terrestrial natural emissions (12-27%), while biomass burning emissions were found to contribute only 1-2%. However, in the western North Pacific near the Asian continent, fossil fuel combustion (27%) and

  1. Characterization of Organic Nitrate Formation in Limonene Secondary Organic Aerosol using High-Resolution Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Faxon, Cameron; Hammes, Julia; Peng, Jianfei; Hallquist, Mattias; Pathak, Ravi

    2016-04-01

    Previous work has shown that organic nitrates (RONO2) are prevalent in the boundary layer, and can contribute significantly to secondary organic aerosol formation. Monoterpenes, including limonene, have been shown to be precursors for the formation of these organic nitrates. Limonene has two double bonds, either of which may be oxidized by NO3 or O3. This leads to the generation of products that can subsequently condense or partition into the particle phase, producing secondary organic aerosol. In order to further elucidate the particle and gas phase product distribution of organic nitrates forming from the reactions of limonene and the nitrate radical (NO3), a series of experiments were performed in the Gothenburg Flow Reactor for Oxidation Studies at Low Temperatures (G-FROST), described by previous work. N2O5 was used as the source for NO3 and NO2, and a characterized diffusion source was used to introduce limonene into the flow reactor. All experiments were conducted in the absence of light, and the concentration of limonene was increased step-wise throughout each experiment to modify the ratio of N2O5to limonene. The experiments were conducted such that both limonene- and N2O5-limited regimes were present. Gas and particle phase products were measured using an iodide High-Resolution Time-of-Flight Mass Spectrometer (HR-ToF-CIMS) coupled to a Filter Inlet for Gases and AEROsols (FIGAERO, and particle size and SOA mass concentrations were derived using a Scanning Mobility Particle Sizer (SMPS). CIMS measurement techniques have previously been employed for the measurement of organic nitrate products of such compounds using multiple reagent ions. The use of this instrumentation allowed for the identification of chemical formulas for gas and particle phase species. The findings from the experiments will be presented in terms of the relative gas-particle partitioning of major products and the effects of N2O5/limonene ratios on product distributions. Additionally, a

  2. Advanced spray-dried design, physicochemical characterization, and aerosol dispersion performance of vancomycin and clarithromycin multifunctional controlled release particles for targeted respiratory delivery as dry powder inhalation aerosols.

    PubMed

    Park, Chun-Woong; Li, Xiaojian; Vogt, Frederick G; Hayes, Don; Zwischenberger, Joseph B; Park, Eun-Seok; Mansour, Heidi M

    2013-10-15

    Respirable microparticles/nanoparticles of the antibiotics vancomycin (VCM) and clarithromycin (CLM) were successfully designed and developed by novel organic solution advanced spray drying from methanol solution. Formulation optimization was achieved through statistical experimental design of pump feeding rates of 25% (Low P), 50% (Medium P) and 75% (High P). Systematic and comprehensive physicochemical characterization and imaging were carried out using scanning electron microscopy (SEM), hot-stage microscopy (HSM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Karl Fischer titration (KFT), laser size diffraction (LSD), gravimetric vapor sorption (GVS), confocal Raman microscopy (CRM) and spectroscopy for chemical imaging mapping. These novel spray-dried (SD) microparticulate/nanoparticulate dry powders displayed excellent aerosol dispersion performance as dry powder inhalers (DPIs) with high values in emitted dose (ED), respirable fraction (RF), and fine particle fraction (FPF). VCM DPIs displayed better aerosol dispersion performance compared to CLM DPIs which was related to differences in the physicochemical and particle properties of VCM and CLM. In addition, organic solution advanced co-spray drying particle engineering design was employed to successfully produce co-spray-dried (co-SD) multifunctional microparticulate/nanoparticulate aerosol powder formulations of VCM and CLM with the essential lung surfactant phospholipid, dipalmitoylphosphatidylcholine (DPPC), for controlled release pulmonary nanomedicine delivery as inhalable dry powder aerosols. Formulation optimization was achieved through statistical experimental design of molar ratios of co-SD VCM:DPPC and co-SD CLM:DPPC. XRPD and DSC confirmed that the phospholipid bilayer structure in the solid-state was preserved following spray drying. Co-SD VCM:DPPC and co-SD CLM:DPPC dry powder aerosols demonstrated controlled release of antibiotic drug that was fitted to various

  3. Overview of the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station

    NASA Astrophysics Data System (ADS)

    Flittner, David; Pitts, Michael; Zawodny, Joe; Hill, Charles; Damadeo, Robert; Moore, Randy; Cisewski, Michael

    2012-07-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) III is the fourth generation of solar occultation instruments operated by NASA, the first coming under a different acronym, to investigate the Earth's upper atmosphere. Three flight-ready SAGE III instruments were built by Ball Aerospace in the late 1990s, with one launched aboard the former Russian Avaiation and Space Agency (now known as Roskosmos) Meteor-3M (M3M) platform on 10 December 2001 (continuing until the platform lost power in 2006). Another of the original instruments was manifested for the International Space Station (ISS) in the 2004 time frame, but was delayed because of budgetary considerations. Fortunately, that SAGE III/ISS mission was restarted in 2009 with a major focus upon filling an anticipated gap in ozone and aerosol observations in the second half of this decade. This exciting mission utilizes contributions from both the Science Mission Directorate and the Human Exploration and Operations Mission Directorate within the National Aeronautics and Space Administration and the European Space Agency to enable scientific measurements that will provide the basis for the analysis of five of the nine critical constituents identified in the U.S. National Plan for Stratospheric Monitoring. A related paper by Anderson et al. discusses the. Presented here is an overview of the mission architecture, its implementation and the data that will be produced by SAGE III/ISS, including their expected accuracy and coverage. The 52-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with excellent coverage of low and mid-latitudes. This is similar to that of the SAGE II mission (1985-2005), whose data set has served the international atmospheric science community as a standard for stratospheric ozone and aerosol measurements. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water

  4. Characterization of an aerosol sample from the auxiliary building of the Three Mile Island reactor.

    PubMed

    Kanapilly, G M; Stanley, J A; Newton, G J; Wong, B A; DeNee, P B

    1983-11-01

    Analyses for radioisotopic composition and dissolution characteristics were performed on an aerosol filter sample collected for a week by an air sampler located in the auxiliary building of the Three Mile Island nuclear reactor. The major radioisotopes found on the filter were 89Sr, 90Sr, 134Cs and 137Cs. Greater than 90% of both 89-90Sr and 134-137Cs dissolved within 48 hr in an in vitro test system. Scanning electron microscopic analyses showed the presence of respirable size particles as well as larger particles ranging up to 10 micron in diameter. The major matrix components were Fe, Ca, S, Mg, Al and Si. Although the radionuclides were present in a heterogeneous matrix, they were in a soluble form. This information enables a better evaluation of bioassay data and predictions of dose distribution resulting from an inhalation exposure to this aerosol. Further, the combination of techniques used in this study may be applicable to the characterization of other aerosols of unknown composition. PMID:6643066

  5. Characterization of an aerosol sample from the auxiliary building of the Three Mile Island reactor.

    PubMed

    Kanapilly, G M; Stanley, J A; Newton, G J; Wong, B A; DeNee, P B

    1983-11-01

    Analyses for radioisotopic composition and dissolution characteristics were performed on an aerosol filter sample collected for a week by an air sampler located in the auxiliary building of the Three Mile Island nuclear reactor. The major radioisotopes found on the filter were 89Sr, 90Sr, 134Cs and 137Cs. Greater than 90% of both 89-90Sr and 134-137Cs dissolved within 48 hr in an in vitro test system. Scanning electron microscopic analyses showed the presence of respirable size particles as well as larger particles ranging up to 10 micron in diameter. The major matrix components were Fe, Ca, S, Mg, Al and Si. Although the radionuclides were present in a heterogeneous matrix, they were in a soluble form. This information enables a better evaluation of bioassay data and predictions of dose distribution resulting from an inhalation exposure to this aerosol. Further, the combination of techniques used in this study may be applicable to the characterization of other aerosols of unknown composition.

  6. Final Technical Report for Interagency Agreement No. DE-SC0005453 “Characterizing Aerosol Distributions, Types, and Optical and Microphysical Properties using the NASA Airborne High Spectral Resolution Lidar (HSRL) and the Research Scanning Polarimeter (RSP)”

    SciTech Connect

    Hostetler, Chris; Ferrare, Richard

    2015-01-13

    Measurements of the vertical profile of atmospheric aerosols and aerosol optical and microphysical characteristics are required to: 1) determine aerosol direct and indirect radiative forcing, 2) compute radiative flux and heating rate profiles, 3) assess model simulations of aerosol distributions and types, and 4) establish the ability of surface and space-based remote sensors to measure the indirect effect. Consequently the ASR program calls for a combination of remote sensing and in situ measurements to determine aerosol properties and aerosol influences on clouds and radiation. As part of our previous DOE ASP project, we deployed the NASA Langley airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 King Air aircraft during major field experiments in 2006 (MILAGRO and MaxTEX), 2007 (CHAPS), 2009 (RACORO), and 2010 (CalNex and CARES). The HSRL provided measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm). These measurements were typically made in close temporal and spatial coincidence with measurements made from DOE-funded and other participating aircraft and ground sites. On the RACORO, CARES, and CalNEX missions, we also deployed the NASA Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP). RSP provided intensity and degree of linear polarization over a broad spectral and angular range enabling column-average retrievals of aerosol optical and microphysical properties. Under this project, we analyzed observations and model results from RACORO, CARES, and CalNex and accomplished the following objectives. 1. Identified aerosol types, characterize the vertical distribution of the aerosol types, and partition aerosol optical depth by type, for CARES and CalNex using HSRL data as we have done for previous missions. 2. Investigated aerosol microphysical and macrophysical properties using the RSP. 3. Used the aerosol backscatter and extinction profiles measured by the HSRL

  7. Stratospheric aerosol and gas experiments I and II comparisons with ozonesondes

    SciTech Connect

    Veiga, R.E.; Cunnold, D.M.; Chu, W.P.

    1995-05-20

    Ozone profiles measured by the Stratospheric Aerosol and Gas Experiments (SAGE) I and II are compared with ozonesonde profiles at 24 stations over the period extending from 1979 through 1991. Ozonesonde/satellite differences at 21 stations with SAGE II overpasses were computed down to 11.5 km in the midlatitudes, to 15.5 km in the lower latitudes, and for nine stations with SAGE I overpasses down to 15.5 km. The set of individual satellite and ozonesonde profile comparisons most closely colocated in time and space shows mean absolute differences relative to the satellite measurement of 6 {plus_minus} 2% for SAGE II and 8 {plus_minus}3% for SAGE I. The ensemble of ozonesonde/satellite differences, when averaged over all altitudes, shows that for SAGE II, 70% were less than 5%, whereas for SAGE I, 50% were less than 5%. The best agreement occurred in the altitude region near the ozone density maximum where almost all the relative differences were less than 5%. Most of the statistically significant differences occurred below the ozone maximum down to the tropopause in the region of steepest ozone gradients and typically ranged between 0 and {minus}20%. Correlations between ozone and aerosol extinction in the northern midlatitudes indicate that aerosols had no discernible impact on the ozonesonde/satellite differences and on the stratosphere during 1984 to mid-1991. 42 refs., 8 figs., 1 tab.

  8. Assessment of aerosol optical property and radiative effect for the layer decoupling cases over the northern South China Sea during the 7-SEAS/Dongsha Experiment

    NASA Astrophysics Data System (ADS)

    Pani, Shantanu Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Tsay, Si-Chee; Lolli, Simone; Chuang, Ming-Tung; Lee, Chung-Te; Chantara, Somporn; Yu, Jin-Yi

    2016-05-01

    The aerosol radiative effect can be modulated by the vertical distribution and optical properties of aerosols, particularly when aerosol layers are decoupled. Direct aerosol radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of aerosol optical properties obtained from the Seven South East Asian Studies (7-SEAS)/Dongsha Experiment into a radiative transfer model. Aerosol optical properties for a two-layer structure of aerosol transport were estimated. In the radiative transfer calculations, aerosol variability (i.e., diversity of source region, aerosol type, and vertical distribution) for the complex aerosol environment was also carefully quantified. The column-integrated aerosol optical depth (AOD) at 500 nm was 0.1-0.3 for near-surface aerosols and increased 1-5 times in presence of upper layer biomass-burning aerosols. A case study showed the strong aerosol absorption (single-scattering albedo (ω) ≈ 0.92 at 440 nm wavelength) exhibited by the upper layer when associated with predominantly biomass-burning aerosols, and the ω (≈0.95) of near-surface aerosols was greater than that of the upper layer aerosols because of the presence of mixed type aerosols. The presence of upper level aerosol transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to -13.7 and +9.6 W m-2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low-latitude marginal northern SCS.

  9. MELCOR 1.8.1 assessment: PNL Ice Condenser Aerosol Experiments

    SciTech Connect

    Gross, R.J.

    1993-06-01

    The MELCOR code was used to simulate PNL`s Ice Condenser Experiments 11-6 and 16-11. In these experiments, ZnS was injected into a mixing chamber, and the combined steam/air/aerosol mixture flowed into an ice condenser which was l4.7m tall. Experiment 11-6 was a low flow test; Experiment l6-1l was a high flow test. Temperatures in the ice condenser region and particle retention were measured in these tests. MELCOR predictions compared very well to the experimental data. The MELCOR calculations were also compared to CONTAIN code calculations for the same tests. A number of sensitivity studies were performed. It as found that simulation time step, aerosol parameters such as the number of MAEROS components and sections used and the particle density, and ice condenser parameters such as the energy capacity of the ice, ice heat transfer coefficient multiplier, and ice heat structure characteristic length all could affect the results. Thermal/hydraulic parameters such as control volume equilibrium assumptions, flow loss coefficients, and the bubble rise model were found to affect the results less significantly. MELCOR results were not machine dependent for this problem.

  10. Atmospheric Radiation Measurment (ARM) Data from the Ganges Valley, India for the Ganges Valley Aerosol Experiment (GVAX)

    DOE Data Explorer

    In 2011 and 2012, the Ganges Valley Aerosol Experiment (GVAX) began in the Ganges Valley region of India. The objective was to obtain measurements of clouds, precipitation, and complex aerosols to study their impact on cloud formation and monsoon activity in the region. During the Indian Ocean Experiment (INDOEX) field studies, aerosols from the Ganges Valley region were shown to affect cloud formation and monsoon activity over the Indian Ocean. The complex field study used the ARM Mobile Facility (AMF) to measure radiative, cloud, convection, and aerosol characteristics over the mainland. The resulting data set captured pre-monsoon to post-monsoon conditions to establish a comprehensive baseline for advancements in the study of the effects of atmospheric conditions of the Ganges Valley.

  11. Time-resolved molecular characterization of organic aerosols by PILS + UPLC/ESI-Q-TOFMS

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Dalleska, N. F.; Huang, D. D.; Bates, K. H.; Sorooshian, A.; Flagan, R. C.; Seinfeld, J. H.

    2016-04-01

    Real-time and quantitative measurement of particulate matter chemical composition represents one of the most challenging problems in the field of atmospheric chemistry. In the present study, we integrate the Particle-into-Liquid Sampler (PILS) with Ultra Performance Liquid Chromatography/Electrospray ionization Quadrupole Time-of-Flight High-Resolution/Mass Spectrometry (UPLC/ESI-Q-TOFMS) for the time-resolved molecular speciation of chamber-derived secondary organic aerosol (SOA). The unique aspect of the combination of these two well-proven techniques is to provide quantifiable molecular-level information of particle-phase organic compounds on timescales of minutes. We demonstrate that the application of the PILS + UPLC/ESI-Q-TOFMS method is not limited to water-soluble inorganic ions and organic carbon, but is extended to slightly water-soluble species through collection efficiency calibration together with sensitivity and linearity tests. By correlating the water solubility of individual species with their O:C ratio, a parameter that is available for aerosol ensembles as well, we define an average aerosol O:C ratio threshold of 0.3, above which the PILS overall particulate mass collection efficiency approaches ∼0.7. The PILS + UPLC/ESI-Q-TOFMS method can be potentially applied to probe the formation and evolution mechanism of a variety of biogenic and anthropogenic SOA systems in laboratory chamber experiments. We illustrate the application of this method to the reactive uptake of isoprene epoxydiols (IEPOX) on hydrated and acidic ammonium sulfate aerosols.

  12. A Multi-Year Aerosol Characterization for the Greater Tehran Area Using Satellite, Surface, and Modeling Data

    PubMed Central

    Crosbie, Ewan; Sorooshian, Armin; Monfared, Negar Abolhassani; Shingler, Taylor; Esmaili, Omid

    2014-01-01

    This study reports a multi-year (2000–2009) aerosol characterization for metropolitan Tehran and surrounding areas using multiple datasets (Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging Spectroradiometer (MISR), Total Ozone Mapping Spectrometer (TOMS), Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART), and surface and upper air data from local stations). Monthly trends in aerosol characteristics are examined in the context of the local meteorology, regional and local emission sources, and air mass back-trajectory data. Dust strongly affects the region during the late spring and summer months (May–August) when aerosol optical depth (AOD) is at its peak and precipitation accumulation is at a minimum. In addition, the peak AOD that occurs in July is further enhanced by a substantial number of seasonal wildfires in upwind regions. Conversely, AOD is at a minimum during winter; however, reduced mixing heights and a stagnant lower atmosphere trap local aerosol emissions near the surface and lead to significant reductions in visibility within Tehran. The unique meteorology and topographic setting makes wintertime visibility and surface aerosol concentrations particularly sensitive to local anthropogenic sources and is evident in the noteworthy improvement in visibility observed on weekends. Scavenging of aerosol due to precipitation is evident during the winter when aconsistent increase in surface visibility and concurrent decrease in AOD is observed in the days after rain compared with the days immediately before rain. PMID:25083295

  13. Aerosol and cloud chemistry of amines from CCS - reactivity experiments and numerical modeling

    NASA Astrophysics Data System (ADS)

    Weller, Christian; Tilgner, Andreas; Herrmann, Hartmut

    2013-04-01

    Capturing CO2 from the exhaust of power plants using amine scrubbing is a common technology. Therefore, amines can be released during the carbon capture process. To investigate the tropospheric chemical fate of amines from CO2 capturing processes and their oxidation products, the impact of aqueous aerosol particles and cloud droplets on the amine chemistry has been considered. Aqueous phase reactivity experiments of NO3 radicals and ozone with relevant amines and their corresponding nitrosamines were performed. Furthermore, nitrosamine formation and nitrosamine photolysis was investigated during laboratory experiments. These experiments implicated that aqueous phase photolysis can be an effective sink for nitrosamines and that ozone is unreactive towards amines and nitrosamines. Multiphase phase oxidation schemes of amines, nitrosamines and amides were developed, coupled to the existing multiphase chemistry mechanism CAPRAM and built into the Lagrangian parcel model SPACCIM using published and newly measured data. As a result, both deliquescent particles and cloud droplets are important compartments for the multiphase processing of amines and their products. Amines can be readily oxidised by OH radicals in the gas and cloud phase during daytime summer conditions. However, amine oxidation is restricted during winter conditions with low photochemical activity leading to long lifetimes of amines. The importance of the gas and aqueous phase depends strongly on the partitioning of the different amines. Furthermore, the simulations revealed that the aqueous formation of nitrosamines in aerosol particles and could droplets is not a relevant process under tropospheric conditions.

  14. Enabling the identification, quantification, and characterization of organics in complex mixtures to understand atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Isaacman, Gabriel Avram

    Particles in the atmosphere are known to have negative health effects and important but highly uncertain impacts on global and regional climate. A majority of this particulate matter is formed through atmospheric oxidation of naturally and anthropogenically emitted gases to yield highly oxygenated secondary organic aerosol (SOA), an amalgamation of thousands of individual chemical compounds. However, comprehensive analysis of SOA composition has been stymied by its complexity and lack of available measurement techniques. In this work, novel instrumentation, analysis methods, and conceptual frameworks are introduced for chemically characterizing atmospherically relevant mixtures and ambient aerosols, providing a fundamentally new level of detailed knowledge on their structures, chemical properties, and identification of their components. This chemical information is used to gain insights into the formation, transformation and oxidation of organic aerosols. Biogenic and anthropogenic mixtures are observed in this work to yield incredible complexity upon oxidation, producing over 100 separable compounds from a single precursor. As a first step toward unraveling this complexity, a method was developed for measuring the polarity and volatility of individual compounds in a complex mixture using two-dimensional gas chromatography, which is demonstrated in Chapter 2 for describing the oxidation of SOA formed from a biogenic compound (longifolene: C15H24). Several major products and tens of substantial minor products were produced, but none could be identified by traditional methods or have ever been isolated and studied in the laboratory. A major realization of this work was that soft ionization mass spectrometry could be used to identify the molecular mass and formula of these unidentified compounds, a major step toward a comprehensive description of complex mixtures. This was achieved by coupling gas chromatography to high resolution time-of-flight mass spectrometry with

  15. Characterization of the 3D distribution of ozone and coarse aerosols in the Troposphere using IASI thermal infrared satellite observations

    NASA Astrophysics Data System (ADS)

    Cuesta, J.; Eremenko, M.; Dufour, G.; Hoepfner, M.; Orphal, J.

    2012-04-01

    Both tropospheric ozone and aerosols significantly affect air quality in megacities during pollution events. Moreover, living conditions may be seriously aggravated when such agglomerations are affected by wildfires (e.g. Russian fires over Moscow in 2010), which produce smoke and pollutant precursors, or even during dense desert dust outbreaks (e.g. recurrently over Beijing or Cairo). Moreover, since aerosols diffuse and absorb solar radiation, they have a direct impact on the photochemical production of tropospheric ozone. These interactions during extreme events of high aerosol loads are nowadays poorly known, even though they may significantly affect the tropospheric photochemical equilibrium. In order to address these issues, we have developed a new retrieval technique to jointly characterize the 3D distribution of both tropospheric ozone and coarse aerosols, using spaceborne observations of the infrared spectrometer IASI onboard MetOp-A satellite. Our methodology is based on the inversion of Earth radiance spectra in the atmospheric window from 8 to 12 μm measured by IASI and a «Tikhonov-Philipps»-type regularisation with constraints varying in altitude (as in [Eremenko et al., 2008, GRL; Dufour et al., 2010 ACP]) to simultaneously retrieve ozone profiles, aerosol optical depths at 10 μm and aerosol layer effective heights. Such joint retrieval prevents biases in the ozone profile retrieval during high aerosol load conditions. Aerosol retrievals using thermal infrared radiances mainly account for desert dust and the coarse fraction of biomass burning aerosols. We use radiances from 15 micro-windows within the 8-12 μm atmospheric window, which were carefully chosen (following [Worden et al., 2006 JGR]) for extracting the maximum information on aerosols and ozone and minimizing contamination by other species. We use the radiative transfer code KOPRA, including line-by-line calculations of gas absorption and single scattering for aerosols [Hoepfner et al

  16. Long-term Chemical Characterization of Submicron Aerosol Particles in the Amazon Forest - ATTO Station

    NASA Astrophysics Data System (ADS)

    Carbone, S.; Brito, J.; Rizzo, L. V.; Holanda, B. A.; Cirino, G. G.; Saturno, J.; Krüger, M. L.; Pöhlker, C.; Ng, N. L.; Xu, L.; Andreae, M. O.; Artaxo, P.

    2015-12-01

    The study of the chemical composition of aerosol particles in the Amazon forest represents a step forward to understand the strong coupling between the atmosphere and the forest. For this reason submicron aerosol particles were investigated in the Amazon forest, where biogenic and anthropogenic aerosol particles coexist at the different seasons (wet/dry). The measurements were performed at the ATTO station, which is located about 150 km northeast of Manaus. At ATTO station the Aerosol chemical speciation monitor (ACSM, Aerodyne) and the Multiangle absorption photometer (MAAP, Thermo 5012) have been operated continuously from March 2014 to July 2015. In this study, long-term measurements (near-real-time, ~30 minutes) of PM1 chemical composition were investigated for the first time in this environment.The wet season presented lower concentrations than the dry season (~5 times). In terms of chemical composition, both seasons were dominated by organics (75 and 63%) followed by sulfate (11 and 13%). Nitrate presented different ratio values between the mass-to-charges 30 to 46 (main nitrate fragments) suggesting the presence of nitrate as inorganic and organic nitrate during both seasons. The results indicated that about 75% of the nitrate signal was from organic nitrate during the dry season. In addition, several episodes with elevated amount of chloride, likely in the form of sea-salt from the Atlantic Ocean, were observed during the wet season. During those episodes, chloride comprised up to 7% of the PM1. During the dry season, chloride was also observed; however, with different volatility, which suggested that Chloride was present in different form and source. Moreover, the constant presence of sulfate and BC during the wet season might be related to biomass burning emissions from Africa. BC concentration was 2.5 times higher during the dry season. Further characterization of the organic fraction was accomplished with the positive matrix factorization (PMF), which

  17. SPEAM-II experiment for the measurement of stratospheric NO2, O3 and aerosols

    NASA Technical Reports Server (NTRS)

    Mcelroy, C. T.; Mcarthur, L. J. B.; Kerr, J. B.; Wardle, D. I.; Tarasick, D.; Midwinter, C.

    1994-01-01

    Following the success of the Sunphotometer Earth Atmosphere Measurement (SPEAM-I) experiment, a more involved experiment was developed to fly as part of the second set of Canadian Experiments (CANEX-2) which will fly on the US Space Shuttle in the fall of 1992. The instrument complement includes an IBM-PC compatible control computer, a hand-held diode array spectrophotometer, and an interference-filter, limb imaging radiometer for the measurement of the atmospheric airglow. The hand-held spectrometer will measure nitrogen dioxide, ozone and aerosols. The limb imaging radiometer will observe emissions from the O2(1 DELTA) and O2(1 SIGMA) airglow bands. Only the spectrophotometer will be discussed here.

  18. Physicochemical Characterization of Coarse Lake Spray Aerosol Particle from Lake Michigan

    NASA Astrophysics Data System (ADS)

    Ault, A. P.; Axson, J. L.; May, N.; Pratt, K.; Colon-Bernal, I. D.

    2015-12-01

    Wave breaking across bodies of water releases coarse particles into the air which can impact climate and human health. Freshwater lakes, such as the Great Lakes, can generate lake spray aerosols (LSA), similarly to how sea spray is generated, during periods of high winds and wave action. This LSA has the potential to impact climate through direct and indirect effects (ie. scattering/absorption and cloud nucleation) and are suggested to impact human health via inhalation of these particles during algal bloom periods characterized by toxic cyanobacteria. Very few studies have been conducted to assess the physicochemical properties of freshwater LSA. Prior work in our lab included the construction and characterization of a laboratory based LSA generator. In this work, we examine laboratory generated aerosol particles from laboratory based freshwater standards, freshwater samples collected from Lake Michigan, and ambient particles collected during a wave event on the shores of Lake Michigan in the summer of 2015. Particle size distributions, number concentrations, and chemical composition are presented and discussed as a function of laboratory generated and ambient collected LSA. Results indicate that there are characteristic particles that represent LSA. This study represents the next step towards evaluating and understanding the potential for coarse LSA to impact climate and health in the Great Lakes region.

  19. Characterization of polar organic compounds and source analysis of fine organic aerosols in Hong Kong

    NASA Astrophysics Data System (ADS)

    Li, Yunchun

    Organic aerosols, as an important fraction of airborne particulate mass, significantly affect the environment, climate, and human health. Compared with inorganic species, characterization of individual organic compounds is much less complete and comprehensive because they number in thousands or more and are diverse in chemical structures. The source contributions of organic aerosols are far from being well understood because they can be emitted from a variety of sources as well as formed from photochemical reactions of numerous precursors. This thesis work aims to improve the characterization of polar organic compounds and source apportionment analysis of fine organic carbon (OC) in Hong Kong, which consists of two parts: (1) An improved analytical method to determine monocarboxylic acids, dicarboxylic acids, ketocarboxylic acids, and dicarbonyls collected on filter substrates has been established. These oxygenated compounds were determined as their butyl ester or butyl acetal derivatives using gas chromatography-mass spectrometry. The new method made improvements over the original Kawamura method by eliminating the water extraction and evaporation steps. Aerosol materials were directly mixed with the BF 3/BuOH derivatization agent and the extracting solvent hexane. This modification improves recoveries for both the more volatile and the less water-soluble compounds. This improved method was applied to study the abundances and sources of these oxygenated compounds in PM2.5 aerosol samples collected in Hong Kong under different synoptic conditions during 2003-2005. These compounds account for on average 5.2% of OC (range: 1.4%-13.6%) on a carbon basis. Oxalic acid was the most abundant species. Six C2 and C3 oxygenated compounds, namely oxalic, malonic, glyoxylic, pyruvic acids, glyoxal, and methylglyoxal, dominated this suite of oxygenated compounds. More efforts are therefore suggested to focus on these small compounds in understanding the role of oxygenated

  20. Production, Organic Characterization, and Phase Transformations of Marine Particles Aerosolized from a Laboratory Mesocosm Phytoplankton Bioreactor

    NASA Astrophysics Data System (ADS)

    Alpert, P. A.; Knopf, D. A.; Aller, J. Y.; Radway, J.; Kilthau, W.

    2012-12-01

    Previous studies have shown that particles emitted from bubble bursting and wave breaking of ocean waters with high biological activity can contain sea salts associated with organic material, with smaller particles containing a larger mass fraction of organics than larger particles. This likely indicates a link between phytoplankton productivity in oceans and particulate organic material in marine air. Once aerosolized, particles with significant amount of organic material can affect cloud activation and formation of ice crystals, among other atmospheric processes, thus influencing climate. This is significant for clouds and climate particularly over nutrient rich polar seas, in which concentrations of biological organisms can reach up to 109 cells per ml during spring phytoplankton blooms. Here we present results of bubble bursting aerosol production from a seawater mesocosm containing artificial seawater, natural seawater and unialgal cultures of three representative phytoplankton species. These phytoplankton (Thalassiosira pseudonana, Emilianaia huxleyi, and Nannochloris atomus), possessed siliceous frustules, calcareous frustules and no frustules, respectively. Bubbles were generated employing recirculating impinging water jets or glass frits. Dry and humidified aerosol size distributions and bulk aerosol organic composition were measured as a function of phytoplankton growth, and chlorophyll composition and particulate and dissolved organic carbon in the water were determined. Finally, particles were collected on substrates for ice nucleation and water uptake experiments, their elemental compositions were determined using computer controlled scanning electron microscopy and energy dispersive analysis of X-rays (CCSEMEDAX), and their carbon speciation was determined using scanning transmission X-ray microscopy and near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Particle size distributions exposed to dry and humidified air employing

  1. Characterization of aerosols in East Asia with the Asian Dust and Aerosol Lidar Observation Network (AD-Net)

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Nishizawa, Tomoaki; Shimizu, Atsushi; Matsui, Ichiro; Jin, Yoshitaka

    2014-11-01

    Continuous observations of aerosols are being conducted with the Asian Dust and aerosol lidar observation Network (AD-Net). Currently, two-wavelength (1064 nm and 532 nm) polarization-sensitive (532 nm) lidars are operated at 20 stations in East Asia. At the primary stations (6 stations), nitrogen vibrational Raman scattering is also measured to obtain the extinction coefficient at 532 nm. Recently, continuous observations with a three-wavelength (1064 nm, 532 nm and 355 nm) lidar having a high-spectral-resolution receiver at 532 nm and a Raman receiver at 355 nm and polarization-sensitive receivers at 532 nm and 355 nm) was started in Tsukuba. Also, continuous observations with multi-wavelength Raman lidars are being prepared in Fukuoka, Okinawa Hedo, and Toyama. A data analysis method for deriving distributions of aerosol components (weak absorption fine (such as sulfate), weak absorption coarse (sea salt), strong absorption fine (black carbon), non-spherical (dust)) has been developed for these multi-parameter lidars. Major subjects of the current studies with AD-Net include data assimilation of multi-parameter lidars, mixing states of Asian dust with air pollution particulate matter, and validation of EarthCARE ATLID based on the aerosol component analysis method.

  2. Characterization of particulate products for aging of ethylbenzene secondary organic aerosol in the presence of ammonium sulfate seed aerosol.

    PubMed

    Huang, Mingqiang; Zhang, Jiahui; Cai, Shunyou; Liao, Yingmin; Zhao, Weixiong; Hu, Changjin; Gu, Xuejun; Fang, Li; Zhang, Weijun

    2016-09-01

    Aging of secondary organic aerosol (SOA) particles formed from OH- initiated oxidation of ethylbenzene in the presence of high mass (100-300μg/m(3)) concentrations of (NH4)2SO4 seed aerosol was investigated in a home-made smog chamber in this study. The chemical composition of aged ethylbenzene SOA particles was measured using an aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with a Fuzzy C-Means (FCM) clustering algorithm. Experimental results showed that nitrophenol, ethyl-nitrophenol, 2,4-dinitrophenol, methyl glyoxylic acid, 5-ethyl-6-oxo-2,4-hexadienoic acid, 2-ethyl-2,4-hexadiendioic acid, 2,3-dihydroxy-5-ethyl-6-oxo-4-hexenoic acid, 1H-imidazole, hydrated N-glyoxal substituted 1H-imidazole, hydrated glyoxal dimer substituted imidazole, 1H-imidazole-2-carbaldehyde, N-glyoxal substituted hydrated 1H-imidazole-2-carbaldehyde and high-molecular-weight (HMW) components were the predominant products in the aged particles. Compared to the previous aromatic SOA aging studies, imidazole compounds, which can absorb solar radiation effectively, were newly detected in aged ethylbenzene SOA in the presence of high concentrations of (NH4)2SO4 seed aerosol. These findings provide new information for discussing aromatic SOA aging mechanisms. PMID:27593289

  3. Scanning Backscatter Lidar Observations for Characterizing 4-D Cloud and Aerosol Fields to Improve Radiative Transfer Parameterizations

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Miller, David O.

    2005-01-01

    Clouds have a powerful influence on atmospheric radiative transfer and hence are crucial to understanding and interpreting the exchange of radiation between the Earth's surface, the atmosphere, and space. Because clouds are highly variable in space, time and physical makeup, it is important to be able to observe them in three dimensions (3-D) with sufficient resolution that the data can be used to generate and validate parameterizations of cloud fields at the resolution scale of global climate models (GCMs). Simulation of photon transport in three dimensionally inhomogeneous cloud fields show that spatial inhomogeneities tend to decrease cloud reflection and absorption and increase direct and diffuse transmission, Therefore it is an important task to characterize cloud spatial structures in three dimensions on the scale of GCM grid elements. In order to validate cloud parameterizations that represent the ensemble, or mean and variance of cloud properties within a GCM grid element, measurements of the parameters must be obtained on a much finer scale so that the statistics on those measurements are truly representative. High spatial sampling resolution is required, on the order of 1 km or less. Since the radiation fields respond almost instantaneously to changes in the cloud field, and clouds changes occur on scales of seconds and less when viewed on scales of approximately 100m, the temporal resolution of cloud properties should be measured and characterized on second time scales. GCM time steps are typically on the order of an hour, but in order to obtain sufficient statistical representations of cloud properties in the parameterizations that are used as model inputs, averaged values of cloud properties should be calculated on time scales on the order of 10-100 s. The Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE) provides exceptional temporal (100 ms) and spatial (30 m) resolution measurements of aerosol and cloud backscatter in three

  4. Aerosol chemical characterization and role of carbonaceous aerosol on radiative effect over Varanasi in central Indo-Gangetic Plain

    NASA Astrophysics Data System (ADS)

    Tiwari, S.; Dumka, U. C.; Kaskaoutis, D. G.; Ram, Kirpa; Panicker, A. S.; Srivastava, M. K.; Tiwari, Shani; Attri, S. D.; Soni, V. K.; Pandey, A. K.

    2016-01-01

    This study investigates the chemical composition of PM10 aerosols at Varanasi, in the central Indo-Gangetic Plain (IGP) during April to July 2011, with emphasis on examining the contribution of elemental carbon (EC) to the estimates of direct aerosol radiative effect (DARE). PM10 samples are analysed for carbonaceous aerosols (Organic Carbon, OC and EC) and water-soluble ionic species (WSIS: Cl-, SO42-, NO3-, PO42- NH4+, Na+, K+, Mg2+ and Ca2+) and several diagnostic ratios (OC/EC, K+/EC, etc) have been also used for studying the aerosol sources at Varanasi. PM10 mass concentration varies between 53 and 310 μg m-3 (mean of 168 ± 73 μg m-3), which is much higher than the National and International air quality standards. The OC mass concentration varies from 6 μg m-3 to 24 μg m-3 (mean of 12 ± 5 μg m-3; 7% of PM10 mass), whereas EC ranges between 1.0 and 14.3 μg m-3 (4.4 ± 3.9 μg m-3; ˜3% of PM10 mass). The relative low OC/EC of 3.9 ± 2.0 and strong correlation (R2 = 0.82) between them suggest the dominance of primary carbonaceous aerosols. The contribution of WSIS to PM10 is found to be ˜12%, out of which ˜57% and 43% are anions and cations, respectively. The composite DARE estimates via SBDART model reveal significant radiative effect and atmospheric heating rates (0.9-2.3 K day-1). Although the EC contributes only ˜3% to the PM10 mass, its contribution to the surface and atmospheric forcing is significantly high (37-63% and 54-77%, respectively), thus playing a major role in climate implications over Varanasi.

  5. Temporal Characterization of Marburg Virus Angola Infection following Aerosol Challenge in Rhesus Macaques

    PubMed Central

    Lin, Kenny L.; Twenhafel, Nancy A.; Connor, John H.; Cashman, Kathleen A.; Shamblin, Joshua D.; Donnelly, Ginger C.; Esham, Heather L.; Wlazlowski, Carly B.; Johnson, Joshua C.; Honko, Anna N.; Botto, Miriam A.; Yen, Judy; Hensley, Lisa E.

    2015-01-01

    ABSTRACT Marburg virus (MARV) infection is a lethal hemorrhagic fever for which no licensed vaccines or therapeutics are available. Development of appropriate medical countermeasures requires a thorough understanding of the interaction between the host and the pathogen and the resulting disease course. In this study, 15 rhesus macaques were sequentially sacrificed following aerosol exposure to the MARV variant Angola, with longitudinal changes in physiology, immunology, and histopathology used to assess disease progression. Immunohistochemical evidence of infection and resulting histopathological changes were identified as early as day 3 postexposure (p.e.). The appearance of fever in infected animals coincided with the detection of serum viremia and plasma viral genomes on day 4 p.e. High (>107 PFU/ml) viral loads were detected in all major organs (lung, liver, spleen, kidney, brain, etc.) beginning day 6 p.e. Clinical pathology findings included coagulopathy, leukocytosis, and profound liver destruction as indicated by elevated liver transaminases, azotemia, and hypoalbuminemia. Altered cytokine expression in response to infection included early increases in Th2 cytokines such as interleukin 10 (IL-10) and IL-5 and late-stage increases in Th1 cytokines such as IL-2, IL-15, and granulocyte-macrophage colony-stimulating factor (GM-CSF). This study provides a longitudinal examination of clinical disease of aerosol MARV Angola infection in the rhesus macaque model. IMPORTANCE In this study, we carefully analyzed the timeline of Marburg virus infection in nonhuman primates in order to provide a well-characterized model of disease progression following aerosol exposure. PMID:26202230

  6. The Cloud Aerosol Interactions and Precipitation Enhancement Experiment (CAIPEEX): overview and prominent results

    NASA Astrophysics Data System (ADS)

    Kulkarni, J. R.; Maheskumar, R. S.; Konwar, M.; Deshpande, C. G.; Morwal, S. B.; Padma Kumari, B.; Joshi, R. R.; Pandithurai, G.; Bhalwankar, R. V.; Mujumdar, V. R.; Goswami, B.; Rosenfeld, D.

    2009-12-01

    “Cloud-Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX)”, an Indian national program, funded by Ministry of Earth Sciences, (MoES), Govt. of India is being conducted by Indian Institute of Tropical Meteorology (IITM), Pune during the period 2009-2012. CAIPEEX has two phases. Phase I is devoted for intensive cloud and aerosol observations over different parts of India using an instrumented aircraft. Phase II is devoted for randomized precipitation enhancement experiment. The phase I is being carried out during the period May-September 2009. The main scientific objectives of Phase I are : To measure background concentrations of aerosols and cloud condensation nuclei (CCN) during pre-monsoon and monsoon seasons over different parts of the country. Measurements of the associated differences in convective cloud microstructure and precipitation forming processes. The important preliminary results from the observational studies are: 1) During the pre-monsoon thick layer of brown haze extends to height of about 5-6 km at the foothills of the Himalaya, but does not normally spill over into the Tibetan Plateau. 2) The deep clouds that form in this layer are typically triggered at the slopes of the Himalaya. The clouds are super-continental microphysically, which means that the cloud drops are very small and prevent any warm rain. However, much ice is formed quickly, probably due to the ice nucleating activity of the aerosols. 3) In the pre-monsoon phase over central and southern India the clouds have similar nature as described for the foothills of the Himalaya, but with lower bases. Still, warm rain is substantially suppressed. During the monsoon, the clouds in the Bangalore-Hyderabad rain shadow area lose quickly their ability to produce warm rain with the increasing levels of CCN eastward away from the west coast. 4) A major finding was the dominance of thick haze in the Arabian Sea during the SW monsoon. It appears to be mostly of Arabian and

  7. Comparison of Stratospheric Aerosol and Gas Experiment II and balloon-borne stratospheric water vapor measurements

    NASA Technical Reports Server (NTRS)

    Pruvost, P.; Ovarlez, J.; Lenoble, J.; Chu, W. P.

    1993-01-01

    The Stratospheric Aerosol and Gas Experiment II has one channel at 940 nm related to water vapor. Two inversion procedures were developed independently in order to obtain the water vapor profile: the Chahine method by the Langley Research Center, and the Mill method by the Laboratoire d'Optique Atmospherique. Comparisons were made between these two algorithms and some results are presented at midlatitudes (about 45 deg N) and tropical latitudes (12-25 deg S). They are compared with in situ frost point hygrometer data provided by balloon experiments from the Laboratoire de Meteorologie Dynamique. At +/- 0.5 ppmv, agreement between the inversion results and the experimental results was obtained in the altitude range from 18-19 to 26-27 km. Below 18-19 km and above 26-27 km the error is larger (sometimes 1 ppmv and more).

  8. Initial operation and checkout of stratospheric aerosol gas experiment and Meteor-3M satellite

    NASA Astrophysics Data System (ADS)

    Habib, Shahid; Makridenko, Leonid; Chu, William P.; Salikhov, Rashid; Moore, Alvah S., Jr.; Trepte, Charles R.; Cisewski, Michael S.

    2003-04-01

    Under a joint agreement between the National Aeronautics and Space Agency (NASA) and the Russian Aviation and Space Agency (RASA), the Stratospheric Aerosol Gas Experiment III (SAGE III) instrument was launched in low earth orbit on December 10, 2001 aboard the Russian Meteor-3M(1) satellite from the Baikonur Cosmodrome. SAGE III is a spectrometer that measures attenuated radiation in the 282 nm to 1550 nm wavelength range to obtain the vertical profiles of ozone, aerosols, and other chemical species that are critical in studying the trends for the global climate change phenomena. This instrument version is more advanced than any of the previous versions and has more spectral bands, elaborate data gathering and storage, and intelligent terrestrial software. There are a number of Russian scientific instruments aboard the Meteor satellite in addition to the SAGE III instrument. These instruments deal with land imaging and biomass changes, hydro-meteorological monitoring, and helio-geophysical research. This mission was under development for over a period of six years and offered a number of unique technical and program management challenges for both Agencies. SAGE III has a long space heritage, and four earlier versions of this instrument have flown in space for nearly two decades now. In fact, SAGE II, the fourth instrument, is still flying in space on NASA's Earth Radiation Budget Satellite (ERBS), and has been providing important atmospheric data over the last 18 years. It has provided vital ozone and aerosol data in the mid latitudes and has contributed vastly in ozone depletion research. Ball Aerospace built the instrument under Langley Research Center's (LaRC) management. This paper presents the process and approach deployed by the SAGE III and the Meteor teams in performing the initial on-orbit checkout. It further documents a number of early science results obtained by deploying low risk, carefully coordinated procedures in resolving the serious operational

  9. Enabling the identification, quantification, and characterization of organics in complex mixtures to understand atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Isaacman, Gabriel Avram

    Particles in the atmosphere are known to have negative health effects and important but highly uncertain impacts on global and regional climate. A majority of this particulate matter is formed through atmospheric oxidation of naturally and anthropogenically emitted gases to yield highly oxygenated secondary organic aerosol (SOA), an amalgamation of thousands of individual chemical compounds. However, comprehensive analysis of SOA composition has been stymied by its complexity and lack of available measurement techniques. In this work, novel instrumentation, analysis methods, and conceptual frameworks are introduced for chemically characterizing atmospherically relevant mixtures and ambient aerosols, providing a fundamentally new level of detailed knowledge on their structures, chemical properties, and identification of their components. This chemical information is used to gain insights into the formation, transformation and oxidation of organic aerosols. Biogenic and anthropogenic mixtures are observed in this work to yield incredible complexity upon oxidation, producing over 100 separable compounds from a single precursor. As a first step toward unraveling this complexity, a method was developed for measuring the polarity and volatility of individual compounds in a complex mixture using two-dimensional gas chromatography, which is demonstrated in Chapter 2 for describing the oxidation of SOA formed from a biogenic compound (longifolene: C15H24). Several major products and tens of substantial minor products were produced, but none could be identified by traditional methods or have ever been isolated and studied in the laboratory. A major realization of this work was that soft ionization mass spectrometry could be used to identify the molecular mass and formula of these unidentified compounds, a major step toward a comprehensive description of complex mixtures. This was achieved by coupling gas chromatography to high resolution time-of-flight mass spectrometry with

  10. The POLARBEAR Experiment: Design and Characterization

    NASA Astrophysics Data System (ADS)

    Kermish, Zigmund David

    We present the design and characterization of the POLARBEAR experiment. POLARBEAR is a millimeter-wave polarimeter that will measure the Cosmic Microwave Background (CMB) polarization. It was designed to have both the sensitivity and angular resolution to detect the expected B-mode polarization due to gravitational lensing at small angular scales while still enabling a search for the degree scale B-mode polarization caused by inflationary gravitational waves. The instrument utilizes the Huan Tran Telescope (HTT), a 2.5-meter primary mirror telescope, coupled to a unique focal plane of 1,274 antenna-coupled transition-edge sensor (TES) detectors to achieve unprecedented sensitivity from angular scales of the experiment's 4 arcminute beam to several degrees. This dissertation focuses on the design, integration and characterization of the cryogenic receiver for the POLARBEAR instrument. The receiver cools the ˜20 cm focal plane to 0.25 Kelvin, with detector readout provided by a digital frequency-multiplexed SQUID system. The POLARBEAR receiver was been successfully deployed on the HTT for an engineering run in the Eastern Sierras of California and is currently deployed on Cerro Toco in the Atacama Dessert of Chile. We present results from lab tests done to characterize the instrument, from the engineering run and preliminary results from Chile.

  11. Method for characterization of low molecular weight organic acids in atmospheric aerosols using ion chromatography mass spectrometry.

    PubMed

    Brent, Lacey C; Reiner, Jessica L; Dickerson, Russell R; Sander, Lane C

    2014-08-01

    The structural composition of PM2.5 monitored in the atmosphere is usually divided by the analysis of organic carbon, black (also called elemental) carbon, and inorganic salts. The characterization of the chemical composition of aerosols represents a significant challenge to analysts, and studies are frequently limited to determination of aerosol bulk properties. To better understand the potential health effects and combined interactions of components in aerosols, a variety of measurement techniques for individual analytes in PM2.5 need to be implemented. The method developed here for the measurement of organic acids achieves class separation of aliphatic monoacids, aliphatic diacids, aromatic acids, and polyacids. The selective ion monitoring capability of a triple quadropole mass analyzer was frequently capable of overcoming instances of incomplete separations. Standard Reference Material (SRM) 1649b Urban Dust was characterized; 34 organic acids were qualitatively identified, and 6 organic acids were quantified.

  12. Characterization of a hooded human exposure apparatus for inhalation of gases and aerosols.

    PubMed

    O'Shaughnessy, Patrick T; Mehaffy, John; Watt, Janet; Sigurdarson, Sigurdur; Kline, Joel N

    2004-03-01

    A human exposure apparatus was designed to administer a gas and/or aerosol directly to the subject's face. This apparatus utilized a hood associated with a powered air-purifying respirator. The design criteria included the need to maximize subject comfort, maintain consistent atmospheres of a gas or dust within the hood, and the accurate use of direct-reading instruments to monitor exposure levels. An 83-L drum was used to pre-mix the gas or aerosol with the main dilution air prior to entering the hood worn by the subject. A clear plastic oxygen tent, ventilated with room exhaust air, was used to contain contaminants exiting the hood. Bypass valves were added to allow for a startup period during which contaminant concentration levels were allowed to stabilize prior to exposing the human subject. Results from characterization studies demonstrated that the system adequately contained contaminants within the oxygen tent, provided adequate mixing of contaminant and dilution air, produced stable contaminant concentrations over time, and was responsive to sudden changes in contaminant generation rate. PMID:15204873

  13. Characterization of Microphysical Properties of Saharan Dust Aerosols During Trans-Atlantic Transport

    NASA Astrophysics Data System (ADS)

    Roldan, L.; Morris, V. R.

    2005-12-01

    The NOAA Center in Atmospheric Sciences (NCAS) Trans-Atlantic Saharan Dust AERosol and Ocean Science Expedition (AEROSE) 2004 was a 27 day mission aboard the NOAA Ship Ronald H. Brown (RHB). The AEROSE mission took place during February 29th thru March 26th, departing from Barbados to the Canary Islands and ending in Puerto Rico. The cruise tracks for AEROSE 2004 coincided with one of the biggest dust storms to date for this season. One of the goals of the mission was to provide a set of critical measurements to characterize the impacts and microphysical evolution of Saharan dust aerosol during Trans-Atlantic transport. A Laser Particle Counter (LPC) was used to retrieve in-situ number density distribution. A Quartz Crystal Microbalance Cascade Impactor (QCM) was used to retrieve in-situ mass density distributions. The QCM also provides a sampling platform for post analysis to determine morphological properties and elemental chemical composition. The morphological properties were determined with the use of a Scanning Electron Microscope (SEM). The combination of the SEM with an Energy Dispersive X-Ray Microanalysis system provides the elemental composition details. I will present the evolution of the chemical elements as a function of size as they are transported. The elemental analysis has identified elements such as Fe, Al, Si, Zn, Ti, Co, S, and C all which are characteristics of Saharan dust origin.

  14. Inversion of solar extinction data from the Apollo-Soyuz Test Project Stratospheric Aerosol Measurement (ASTP/SAM) experiment

    NASA Technical Reports Server (NTRS)

    Pepin, T. J.

    1977-01-01

    The inversion methods are reported that have been used to determine the vertical profile of the extinction coefficient due to the stratospheric aerosols from data measured during the ASTP/SAM solar occultation experiment. Inversion methods include the onion skin peel technique and methods of solving the Fredholm equation for the problem subject to smoothing constraints. The latter of these approaches involves a double inversion scheme. Comparisons are made between the inverted results from the SAM experiment and near simultaneous measurements made by lidar and balloon born dustsonde. The results are used to demonstrate the assumptions required to perform the inversions for aerosols.

  15. Secondary organic aerosol (trans)formation through aqueous phase guaiacol photonitration: chemical characterization of the products

    NASA Astrophysics Data System (ADS)

    Grgić, Irena; Kitanovski, Zoran; Kroflič, Ana; Čusak, Alen

    2014-05-01

    One of the largest primary sources of organic aerosol in the atmosphere is biomass burning (BB) (Laskin et al. 2009); in Europe its contribution to annual mean of PM10 is between 3 and 14 % (Maenhaut et al. 2012). During the process of wood burning many different products are formed via thermal degradation of wood lignin. Hardwood burning produces mainly syringol (2,6-dimetoxyphenol) derivatives, while softwood burning exclusively guaiacol (2-methoxyphenol) and its derivatives. Taking into account physical properties of methoxyphenols only, their concentrations in atmospheric waters might be underestimated. So, their aqueous phase reactions can be an additional source of SOA, especially in regions under significant influence of wood combustion. An important class of compounds formed during physical and chemical aging of the primary BBA in the atmosphere is nitrocatechols, known as strong absorbers of UV and Vis light (Claeys et al. 2012). Very recently, methyl-nitrocatechols were proposed as suitable markers for highly oxidized secondary BBA (Iinuma et al. 2010, Kitanovski et al. 2012). In the present work, the formation of SOA through aqueous phase photooxidation and nitration of guaiacol was examined. The key objective was to chemically characterize the main low-volatility products and further to check their possible presence in the urban atmospheric aerosols. The aqueous phase reactions were performed in a thermostated reactor under simulated sunlight in the presence of H2O2 and nitrite. Guaiacol reaction products were first concentrated by solid-phase extraction (SPE) and then subjected to semi-preparative liquid chromatography.The main product compounds were fractionated and isolated as pure solids and their structure was further elucidated by using nuclear magnetic resonance spectroscopy (1H, 13C and 2D NMR) and direct infusion negative ion electro-spray ionization tandem mass spectrometry (( )ESI-MS/MS). The main photonitration products of guaiacol (4

  16. Experience with Aerosol Generation During Rotary Mode Core Sampling in the Hanford Single Shell Waste Tanks

    SciTech Connect

    SCHOFIELD, J.S.

    2000-01-24

    This document provides data on aerosol concentrations in tank head spaces, total mass of aerosols in the tank head space and mass of aerosols sent to the exhauster during Rotary Mode Core Sampling from November 1994 through June 1999. A decontamination factor for the RMCS exhauster filter housing is calculated based on operation data.

  17. Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

    NASA Astrophysics Data System (ADS)

    Forestieri, Sara D.; Cornwell, Gavin C.; Helgestad, Taylor M.; Moore, Kathryn A.; Lee, Christopher; Novak, Gordon A.; Sultana, Camille M.; Wang, Xiaofei; Bertram, Timothy H.; Prather, Kimberly A.; Cappa, Christopher D.

    2016-07-01

    The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA) particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 %)) of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs). One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 %) values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 %) measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer) and single particle (using an aerosol time-of-flight mass spectrometer) measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 %) values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 %) depression and the peak chlorophyll a (Chl a) concentrations by either 1 (indoor MART) or 3-to-6 (outdoor MART) days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 %) values (relative to pure sea salt) is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM) comprising the SSA. The GF(85 %) values exhibited a reasonable negative

  18. CalWater 2 - Precipitation, Aerosols, and Pacific Atmospheric Rivers Experiment

    NASA Astrophysics Data System (ADS)

    Spackman, Ryan; Ralph, Marty; Prather, Kim; Cayan, Dan; DeMott, Paul; Dettinger, Mike; Fairall, Chris; Leung, Ruby; Rosenfeld, Daniel; Rutledge, Steven; Waliser, Duane; White, Allen

    2014-05-01

    Emerging research has identified two phenomena that play key roles in the variability of the water supply and the incidence of extreme precipitation events along the West Coast of the United States. These phenomena include the role of (1) atmospheric rivers (ARs) in delivering much of the precipitation associated with major storms along the U.S. West Coast, and (2) aerosols—from local sources as well as those transported from remote continents—and their modulating effects on western U.S. precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of extreme precipitation and its effects, including the provision of beneficial water supply. This presentation summarizes science gaps associated with (1) the evolution and structure of ARs including cloud and precipitation processes and air-sea interaction, and (2) aerosol interaction with ARs and the impact on precipitation, including locally-generated aerosol effects on orographic precipitation along the U.S. West Coast. Observations are proposed for multiple winter seasons as part of a 5-year broad interagency vision referred to as CalWater 2 to address these science gaps (http://esrl.noaa.gov/psd/calwater). In the near term, a science investigation is being planned including a targeted set of aircraft and ship-based measurements and associated evaluation of data in near-shore regions of California and in the eastern Pacific for an intensive observing period between January 2015 and March 2015. DOE's Atmospheric Radiation Measurement (ARM) program and NOAA are coordinating on deployment of airborne and ship-borne facilities for this period in a DOE-sponsored study called ACAPEX (ARM Cloud Aerosol and Precipitation Experiment) to complement CalWater 2. The motivation for this major study is based on findings that have emerged in the last few years from airborne and ground-based studies including CalWater and NOAA's HydroMeterology Testbed

  19. Lidar Observations of Tropospheric Aerosols Over Northeastern South Africa During the ARREX and SAFARI-2000 Dry Season Experiments

    NASA Technical Reports Server (NTRS)

    Campbell, James R.; Welton, Ellsworth J.; Spinhirne, James D.; Ji, Qiang; Tsay, Si-Chee; Piketh, Stuart J.; Barenbrug, Marguerite; Holben, Brent; Starr, David OC. (Technical Monitor)

    2002-01-01

    During the ARREX-1999 and SAFARI-2000 Dry Season experiments a micropulse lidar (523 nm) instrument was operated at the Skukuza Airport in northeastern South Africa. The Mar was collocated with a diverse array of passive radiometric equipment. For SAFARI-2000 the processed Mar data yields a daytime time-series of layer mean/derived aerosol optical properties, including extinction-to-backscatter ratios and vertical extinction cross-section profile. Combined with 523 run aerosol optical depth and spectral Angstrom exponent calculations from available CIMEL sun-photometer data and normalized broadband flux measurements the temporal evolution of the near surface aerosol layer optical properties is analyzed for climatological trends. For the densest smoke/haze events the extinction-to-backscatter ratio is found to be between 60-80/sr, and corresponding Angstrom exponent calculations near and above 1.75. The optical characteristics of an evolving smoke event from SAFARI-2000 are extensively detailed. The advecting smoke was embedded within two distinct stratified thermodynamic layers, causing the particulate mass to advect over the instrument array in an incoherent manner on the afternoon of its occurrence. Surface broadband flux forcing due to the smoke is calculated, as is the evolution in the vertical aerosol extinction profile as measured by the Han Finally, observations of persistent elevated aerosol during ARREX-1999 are presented and discussed. The lack of corroborating observations the following year makes these observation; both unique and noteworthy in the scope of regional aerosol transport over southern Africa.

  20. The VOCALS Regional Experiment: Aerosol-Cloud-Precipitation Interactions in Marine Boundary Layer Cloud

    NASA Astrophysics Data System (ADS)

    Wood, R.

    2012-12-01

    Robert Wood, C.S. Bretherton, C. R. Mechoso, R. A. Weller, B. J. Huebert, H. Coe, B. A. Albrecht, P. H. Daum, D. Leon, A. Clarke, P. Zuidema, C. W. Fairall, G. Allen, S. deSzoeke, G. Feingold, J. Kazil, S. Yuter, R. George, A. Berner, C. Terai, G. Painter, H. Wang, M. Wyant, D. Mechem The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) is an international field program designed to make observations of poorly understood but critical components of the coupled climate system of the southeast Pacific (SEP), a region dominated by strong coastal upwelling, extensive cold SSTs, and home to the largest subtropical stratocumulus deck on Earth. VOCALS-REx took place during October and November 2008 and involved five research aircraft, two ships and two surface sites in northen Chile. A central theme of VOCALS-REx is the improved understanding of links between aerosols, clouds and precipitation and their impacts on marine stratocumulus radiative properties. In this presentation, we will present a synthesis of results from VOCALS-REx focusing on the following questions: (a) how are aerosols, clouds and precipitation inter-related in the SEP region? (b) what microphysical-macrophysical interactions are necessary for the formation and maintenance of open cells? (c) how do cloud and MBL properties change across the strong microphysical gradients from the South American coast to the remote ocean?

  1. Algorithms and sensitivity analyses for stratospheric aerosol and gas experiment II water vapor retrieval

    SciTech Connect

    Chu, W.P.; Thomason, L.W.; Buglia, J.J.; McCormick, M.P.; McMaster, L.M. ); Chiou, E.W.; Larsen, J.C. ); Rind, D. ); Oltmans, S. )

    1993-03-20

    This paper provides a detailed description of the current operational inversion algorithm for the retrieval of water vapor vertical profiles from the Stratospheric Aerosol and Gas Experiment II (SAGE II) occultation data at the 0.94-[mu]m wavelength channel. This algorithm is different from the algorithm used for the retrieval of the other species such as aerosol, ozone, and nitrogen dioxide because of the nonlinear relationship between the concentration versus the broad band absorption characteristics of water vapor. Included in the discussion of the retrieval algorithm are problems related to the accuracy of the computational scheme, accuracy of the removal of other interfering species, and the expected uncertainty of the retrieved profile. A comparative analysis on the computational schemes used for the calculation of the water vapor transmission at the 0.94-[mu]m wavelength region is presented. Analyses are also presented on the sensitivity of the retrievals to interferences from the other species which contribute to the total signature as observed at the 0.94-[mu]m wavelength channel on SAGE II instrument. Error analyses of the SAGE II water vapor retrieval is shown, indicating that good quality water vapor data are being produced by the SAGE II measurements. 27 refs., 10 figs., 1 tab.

  2. Characterization of organic compounds in the PM2.5 aerosols in winter in an industrial urban area

    NASA Astrophysics Data System (ADS)

    Mikuška, P.; Křůmal, K.; Večeřa, Z.

    2015-03-01

    Urban aerosol particles in the fine fraction (PM2.5) were collected over the sampling interval of 24-hrs on quartz filters in Ostrava (Czech Republic) in winter 2012. The collected aerosols were analysed for selected organic compounds that serve as tracers of the main emission sources. The campaign was carried out under two different meteorological scenarios. During a smog episode due to high concentration of aerosols in the first part of the campaign, high concentrations of PM2.5 aerosols (mean concentration of 159 μg m-3) and PAHs bound to particles were found, while in the second part of the campaign, after the smog episode, much lower concentrations of aerosols (mean concentration of 49.3 μg m-3) were observed. Analysis of the source specific molecular markers and diagnostic ratios of PAHs, hopanes and alkanes imply that combustion of coniferous wood and coal in residential heating and traffic belong to the biggest emission sources of organic compounds associated with the PM2.5 aerosols collected during the winter campaign in Ostrava-Radvanice. The industrial production of coke and iron is another important contributor to the concentrations of BaP and other carcinogenic PAHs. The level of air pollution in Ostrava-Radvanice was considerably determined by the overall meteorological situation during the campaign. The highest concentrations of PM2.5 and bound organic compounds were found during a smog episode characterized by poor dispersion conditions due to temperature inversion and weak north-eastern wind, while during the subsequent period characterized by north-west or west wind, the concentrations of aerosols and bound organic compounds were much lower. Transboundary transport of polluted air from the Silesian Voivodeship could have contributed to the pollution in the Moravian-Silesian region during the smog episode.

  3. Aerosol ultraviolet absorption experiment (2002 to 2004), part 2: absorption optical thickness, refractive index, and single scattering albedo

    NASA Astrophysics Data System (ADS)

    Krotkov, Nickolay A.; Bhartia, Pawan K.; Herman, Jay R.; Slusser, James R.; Scott, Gwendolyn R.; Labow, Gordon J.; Vasilkov, Alexander P.; Eck, Tom; Doubovik, Oleg; Holben, Brent N.

    2005-04-01

    Compared to the visible spectral region, very little is known about aerosol absorption in the UV. Without such information it is impossible to quantify the causes of the observed discrepancy between modeled and measured UV irradiances and photolysis rates. We report results of a 17-month aerosol column absorption monitoring experiment conducted in Greenbelt, Maryland, where the imaginary part of effective refractive index k was inferred from the measurements of direct and diffuse atmospheric transmittances by a UV-multifilter rotating shadowband radiometer [UV-MFRSR, U.S. Department of Agriculture (USDA) UV-B Monitoring and Research Network]. Colocated ancillary measurements of aerosol effective particle size distribution and refractive index in the visible wavelengths [by CIMEL sun-sky radiometers, National Aeronautics and Space Administration (NASA) Aerosol Robotic Network (AERONET)], column ozone, surface pressure, and albedo constrain the forward radiative transfer model input, so that a unique solution for k is obtained independently in each UV-MFRSR spectral channel. Inferred values of k are systematically larger in the UV than in the visible wavelengths. The inferred k values enable calculation of the single scattering albedo ω, which is compared with AERONET inversions in the visible wavelengths. On cloud-free days with high aerosol loadings [τext(440)>0.4], ω is systematically lower at 368 nm (<ω368>=0.94) than at 440 nm (<ω440>=0.96), however, the mean ω differences (0.02) are within expected uncertainties of ω retrievals (~0.03). The inferred ω is even lower at shorter UV wavelengths (<ω325>~<ω332>=0.92), which might suggest the presence of selectively UV absorbing aerosols. We also find that decreases with decrease in aerosol loading. This could be due to real changes in the average aerosol composition between summer and winter months at the Goddard Space Flight Center (GSFC) site.

  4. Preface to special section on East Asian Studies of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE)

    NASA Astrophysics Data System (ADS)

    Li, Zhanqing; Chen, H.; Cribb, M.; Dickerson, R.; Holben, B.; Li, C.; Lu, D.; Luo, Y.; Maring, H.; Shi, G.; Tsay, S.-C.; Wang, P.; Wang, Y.; Xia, X.; Zheng, Y.; Yuan, T.; Zhao, F.

    2007-11-01

    Papers published in this special section report findings from the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE). They are concerned with (1) the temporal and spatial distributions of aerosol loading and precursor gases, (2) aerosol single scattering albedo (SSA), (3) aerosol direct radiative effects, (4) validation of satellite products, (5) transport mechanisms, and (6) the effects of air pollution on ecosystems. Aerosol loading is heaviest in mideastern China with a mean aerosol optical depth (AOD) of 0.5 and increasing to 0.7 around major cities that reduced daily mean surface solar radiation by ˜30-40 W m-2, but barely changed solar reflection at the top of the atmosphere. Aerosol loading, particle size and composition vary considerably with location and season. The MODIS AOD data from Collection 5 (C5) agree much better with ground data than earlier releases, but considerable discrepancies still exist because of treatments of aerosol SSA and surface albedo. Four methods are proposed/adopted to derive the SSA by means of remote sensing and in situ observation, which varies drastically with time and space. The nationwide means of AOD, Ångström exponent, and SSA (0.5 μm) in China are 0.69 ± 0.17, 1.06 ± 0.26, and 0.89 ± 0.04, respectively. Measurements of trace gases reveal substantial uncertainties in emission inventories. An analysis of aircraft measurements revealed that dry convection is an important mechanism uplifting pollutants over northern China. Model simulations of nitrogen deposition and impact of ozone pollution on net primary productivity indicate an increasing threat of air pollution on the ecosystem.

  5. Experiments In Characterizing Vibrations Of A Structure

    NASA Technical Reports Server (NTRS)

    Yam, Yeung; Hadaegh, Fred Y.; Bayard, David S.

    1993-01-01

    Report discusses experiments conducted to test methods of identification of vibrational and coupled rotational/vibrational modes of flexible structure. Report one in series that chronicle development of integrated system of methods, sensors, actuators, analog and digital signal-processing equipment, and algorithms to suppress vibrations in large, flexible structure even when dynamics of structure partly unknown and/or changing. Two prior articles describing aspects of research, "Autonomous Frequency-Domain Indentification" (NPO-18099), and "Automated Characterization Of Vibrations Of A Structure" (NPO-18141).

  6. A Characterization of Arctic Aerosols as Derived from Airborne Observations and their Influence on the Surface Radiation Budget

    NASA Astrophysics Data System (ADS)

    Herber, A.; Stone, R.; Liu, P. S.; Li, S.; Sharma, S.; Neuber, R.; Birnbaumn, G.; Vitale, V.

    2011-12-01

    Arctic climate is influenced by aerosols that affect the radiation balance at the surface and within the atmosphere. Impacts depend on the composition and concentration of aerosols that determine opacity, which is quantified by the measure of aerosol optical depth (AOD). During winter and spring, aerosols are transported into the Arctic from lower latitude industrial regions. Trans-Arctic flight missions PAMARCMiP (Polar Airborne Measurements and Arctic Regional Climate Model Simulation Project) of the German POLAR 5 during spring 2009 and spring 2011 provided opportunities to collect a comprehensive data set from which properties of the aerosol were derived, including AOD. Measurements were made from near the surface to over 4 km in altitude during flights between Svalbard, Norway and Pt. Barrow, Alaska. These, along with measurements of particle size and concentration, and black carbon content (BC) provide a three-dimensional characterization of the aerosols encountered along track. The horizontal and vertical distribution of Arctic haze, in particular, was evaluated. During April 2009, the Arctic atmosphere was variably turbid with total column AOD (at 500 nm) ranging from ~ 0.12 to > 0.35, where clean background values are typically < 0.06 (Stone et al., 2010). The haze was concentrated within and just above the surface-based temperature inversion layer. Few, distinct elevated aerosol layers were observed, also with an aerosol airborne Lidar. The presence of these haze layers in the Arctic atmosphere during spring reduced the diurnally averaged net shortwave irradiance, which can cause cooling of the surface, depending on its Albedo (reflectivity). An overview of both campaigns will be given with results presented in the context of historical observations and current thinking about the impact aerosols have on the Arctic climate. Stone, R.S., A. Herber, V. Vitale, M. Mazzola, A. Lupi, R. Schnell, E.G. Dutton, P. Liu, S.M. Li, K. Dethloff, A. Lampert, C. Ritter

  7. Impact of aftertreatment devices on primary emissions and secondary organic aerosol formation potential from in-use diesel vehicles: results from smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Chirico, R.; Decarlo, P. F.; Heringa, M. F.; Tritscher, T.; Richter, R.; Prévôt, A. S. H.; Dommen, J.; Weingartner, E.; Wehrle, G.; Gysel, M.; Laborde, M.; Baltensperger, U.

    2010-12-01

    Diesel particulate matter (DPM) is a significant source of aerosol in urban areas and has been linked to adverse health effects. Although newer European directives have introduced increasingly stringent standards for primary PM emissions, gaseous organics emitted from diesel cars can still lead to large amounts of secondary organic aerosol (SOA) in the atmosphere. Here we present results from smog chamber investigations characterizing the primary organic aerosol (POA) and the corresponding SOA formation at atmospherically relevant concentrations for three in-use diesel vehicles with different exhaust aftertreatment systems. One vehicle lacked exhaust aftertreatment devices, one vehicle was equipped with a diesel oxidation catalyst (DOC) and the third vehicle used both a DOC and diesel particulate filter (DPF). The experiments presented here were obtained from the vehicles at conditions representative of idle mode, and for one car in addition at a speed of 60 km/h. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to measure the organic aerosol (OA) concentration and to obtain information on the chemical composition. For the conditions explored in this paper, primary aerosols from vehicles without a particulate filter consisted mainly of black carbon (BC) with a low fraction of organic matter (OM, OM/BC < 0.5), while the subsequent aging by photooxidation resulted in a consistent production of SOA only for the vehicles without a DOC and with a deactivated DOC. After 5 h of aging ~80% of the total organic aerosol was on average secondary and the estimated "emission factor" for SOA was 0.23-0.56 g/kg fuel burned. In presence of both a DOC and a DPF, only 0.01 g SOA per kg fuel burned was produced within 5 h after lights on. The mass spectra indicate that POA was mostly a non-oxidized OA with an oxygen to carbon atomic ratio (O/C) ranging from 0.10 to 0.19. Five hours of oxidation led to a more oxidized OA with an O/C range of 0

  8. Impact of aftertreatment devices on primary emissions and secondary organic aerosol formation potential from in-use diesel vehicles: results from smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Chirico, R.; Decarlo, P. F.; Heringa, M. F.; Tritscher, T.; Richter, R.; Prevot, A. S. H.; Dommen, J.; Weingartner, E.; Wehrle, G.; Gysel, M.; Laborde, M.; Baltensperger, U.

    2010-06-01

    Diesel particulate matter (DPM) is a significant source of aerosol in urban areas and has been linked to adverse health effects. Although newer European directives have introduced increasingly stringent standards for primary PM emissions, gaseous organics emitted from diesel cars can still lead to large amounts of secondary organic aerosol (SOA) in the atmosphere. Here we present results from smog chamber investigations characterizing the primary organic aerosol (POA) and the corresponding SOA formation at atmospherically relevant concentrations for three in-use diesel vehicles with different exhaust aftertreatment systems. One vehicle lacked exhaust aftertreatment devices, one vehicle was equipped with a diesel oxidation catalyst (DOC) and the final vehicle used both a DOC and diesel particulate filter (DPF). The experiments presented here were obtained from the vehicles at conditions representative of idle mode, and for one car in addition at a speed of 60 km/h. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to measure the organic aerosol (OA) concentration and to obtain information on the chemical composition. For the conditions explored in this paper, primary aerosols from vehicles without a particulate filter consisted mainly of black carbon (BC) with a low fraction of organic matter (OM, OM/BC<0.5), while the subsequent aging by photooxidation resulted in a consistent production of SOA only for the vehicles without a DOC and with a deactivated DOC. After 5 h of aging ~80% of the total organic aerosol was on average secondary and the estimated "emission factor" for SOA was 0.23-0.56 g/kg fuel burned. In presence of both a DOC and a DPF, primary particles with a mobility diameter above 5 nm were 300±19 cm-3, and only 0.01 g SOA per kg fuel burned was produced within 5 h after lights on. The mass spectra indicate that POA was mostly a non-oxidized OA with an oxygen to carbon atomic ratio (O/C) ranging from 0.097 to 0

  9. The solvent-extractable organic compounds in the Indonesia biomass burning aerosols - characterization studies

    NASA Astrophysics Data System (ADS)

    Fang, M.; Zheng, M.; Wang, F.; To, K. L.; Jaafar, A. B.; Tong, S. L.

    for n-alkanols, and the presence of abundant moretane (17 β(H), 21 α(H)-hopanes). The biomarkers dehydroabietic acid and retene were not found in the samples suggesting there is a difference in the long-distance transport samples of an Asian forest fire and the controlled experiments reported in the literature. Similar to the biomass burning in Amazonia (Abas et al., 1995), the present study also showed an absence of conifer tracers in the smoke aerosols indicating tropical wood sources. Abundant friedelin, a specific biomarker for smoke from oak wood fires (Standley and Simoneit, 1990), was present in the late September samples when the fire was more intense. The results were compared to literature values from an earlier study of the haze episode on 29 September 1991 in Kuala Lumpur, Malaysia (Abas and Simoneit, 1996).

  10. Characterization of atmospheric aerosols from infrared measurements: simulations, testing, and applications.

    PubMed

    Zasetsky, Alexander Yu; Khalizov, Alexei F; Sloan, James J

    2004-10-10

    An inversion method for the characterization of atmospheric condensed phases from infrared (IR) spectra is described. The method is tested with both synthetic IR spectra and the spectra of particles that flow in a cryogenic flow tube. The method is applied to the IR spectra recorded by the Atmospheric Trace Molecule Spectroscopy instrument carried by the Space Shuttle during three missions in 1992, 1993, and 1994. The volume density and particle size distribution for sulfate aerosol are obtained as a function of altitude. The density and size distribution of ice particles in several cirrus clouds are also retrieved. The probable radius of the ice particles in the high-altitude (10-15-km) cirrus clouds is found to be approximately 6-7 microm.

  11. Charged aerosol detection to characterize components of dispersed-phase formulations.

    PubMed

    Fox, Christopher B; Sivananthan, Sandra J; Mikasa, Traci J T; Lin, Susan; Parker, Sarah C

    2013-11-01

    Colloidal formulations based on biocompatible phospholipids, emulsifiers, and oils are employed in a wide range of applications including medicine, food, and cosmetics. However, characterization of these dispersed-phase components may be difficult to analyze by traditional HPLC with UV, visible, or fluorescence detection modalities due to lack of chromophores or fluorophores. Charged aerosol detection (CAD) is increasingly used for analysis of dispersed-phase components due to its broad applicability and high sensitivity for non-chromophore containing components found in many colloidal systems, such as lipid-based molecules. In this review, we summarize the recent applications of CAD reported in the literature as well as our own laboratory for the analysis of widely used components of dispersed-phase systems. In particular, we discuss the advantages and disadvantages of CAD compared to other HPLC detection methods, as well as the various sample preparation methods suitable for colloidal formulations prior to HPLC-CAD analysis. PMID:23855968

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

    NASA Astrophysics Data System (ADS)

    Ro, C.

    2008-12-01

    An electron probe X-ray microanalysis (EPMA) technique using an energy-dispersive X-ray detector with an ultra-thin window, named low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements such as C, N, and O, as well as higher-Z elements that can be analyzed by conventional energy-dispersive EPMA (ED-EPMA). The quantitative determination of low-Z elements (using full Monte Carlo simulations, from the electron impact to the X-ray detection) in individual environmental particles has improved the applicability of single-particle analysis, especially in atmospheric environmental aerosol research; many environmentally important atmospheric particles, e.g. sulfates, nitrates, ammonium, and carbonaceous particles, contain low-Z elements. In addition, an expert system that can perform chemical speciation from the elemental composition data obtained by the low-Z particle EPMA has been developed. The low-Z particle EPMA was applied to characterize K-feldspar particle samples of which the chemical compositions are well defined by the use of various bulk analytical methods. Chemical compositions of the K-feldspar samples obtained from the low-Z particle EPMA turn out to be very close to those from bulk analyses. The low-Z particle EPMA technique has been applied for the characterization of atmospheric aerosol particle samples, including Asian dust, urban, and indoor particulate samples: (1) The extent of chemical modification of Asian dust particles sampled in Chuncheon and Incheon, Korea, during several Asian dust storm events occurred in 2002-2006 was investigated. Mixing of Asian dust with air pollutants and sea-salts strongly depends on the characteristics of Asian dust storm events such as air-mass backward trajectories. For instance, no significant chemical modification of mineral dust corresponded to fast moving air-masses at high altitudes. Inversely, extensive chemical modification was

  13. Micropulse lidar observations of tropospheric aerosols over northeastern South Africa during the ARREX and SAFARI 2000 dry season experiments

    NASA Astrophysics Data System (ADS)

    Campbell, James R.; Welton, Ellsworth J.; Spinhirne, James D.; Ji, Qiang; Tsay, Si-Chee; Piketh, Stuart J.; Barenbrug, Marguerite; Holben, Brent N.

    2003-07-01

    During the Aerosol Recirculation and Rainfall Experiment (ARREX 1999) and Southern African Regional Science Initiative (SAFARI 2000) dry season experiments, a micropulse lidar (523 nm) instrument was operated at the Skukuza Airport in northeastern South Africa. The lidar was colocated with a diverse array of passive radiometric equipment. For SAFARI 2000, a daytime time series of layer mean aerosol optical properties, including layer mean extinction-to-backscatter ratios and vertical extinction cross-section profiles are derived from the synthesis of the lidar data and aerosol optical depths from available AERONET Sun photometer data. Combined with derived spectral Angstrom exponents, normalized broadband flux measurements, and calculated air mass back-trajectories, the temporal evolution of the surface aerosol layer optical properties is analyzed for climatological trends. For dense biomass smoke events the extinction-to-backscatter ratio is between 50 and 90 sr, and corresponding spectral Angstrom exponent values are between 1.50 and 2.00. Observations of an advecting smoke event during SAFARI 2000 are shown. The smoke was embedded within two distinct stratified thermodynamic layers causing the particulate mass to advect over the instrument array in an incoherent manner on the afternoon of 1 September 2000. Significant surface broadband flux forcing of over -50 W/m2 was measured in this event. The evolution of the vertical aerosol extinction profile is profiled using the lidar data. Finally, observations of persistent elevated aerosol layers during ARREX 1999 are presented and discussed. Back-trajectory analyses combined with lidar and Sun photometer measurements indicate the likelihood for these aerosols being the result of long-range particulate transport from the southern and central South America.

  14. Seasonal characterization of submicron aerosol chemical composition and organic aerosol sources in the southeastern United States: Atlanta, Georgia,and Look Rock, Tennessee

    NASA Astrophysics Data System (ADS)

    Hapsari Budisulistiorini, Sri; Baumann, Karsten; Edgerton, Eric S.; Bairai, Solomon T.; Mueller, Stephen; Shaw, Stephanie L.; Knipping, Eladio M.; Gold, Avram; Surratt, Jason D.

    2016-04-01

    A year-long near-real-time characterization of non-refractory submicron aerosol (NR-PM1) was conducted at an urban (Atlanta, Georgia, in 2012) and rural (Look Rock, Tennessee, in 2013) site in the southeastern US using the Aerodyne Aerosol Chemical Speciation Monitor (ACSM) collocated with established air-monitoring network measurements. Seasonal variations in organic aerosol (OA) and inorganic aerosol species are attributed to meteorological conditions as well as anthropogenic and biogenic emissions in this region. The highest concentrations of NR-PM1 were observed during winter and fall seasons at the urban site and during spring and summer at the rural site. Across all seasons and at both sites, NR-PM1 was composed largely of OA (up to 76 %) and sulfate (up to 31 %). Six distinct OA sources were resolved by positive matrix factorization applied to the ACSM organic mass spectral data collected from the two sites over the 1 year of near-continuous measurements at each site: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), semi-volatile oxygenated OA (SV-OOA), low-volatility oxygenated OA (LV-OOA), isoprene-derived epoxydiols (IEPOX) OA (IEPOX-OA) and 91Fac (a factor dominated by a distinct ion at m/z 91 fragment ion previously observed in biogenic influenced areas). LV-OOA was observed throughout the year at both sites and contributed up to 66 % of total OA mass. HOA was observed during the entire year only at the urban site (on average 21 % of OA mass). BBOA (15-33 % of OA mass) was observed during winter and fall, likely dominated by local residential wood burning emission. Although SV-OOA contributes quite significantly ( ˜ 27 %), it was observed only at the urban site during colder seasons. IEPOX-OA was a major component (27-41 %) of OA at both sites, particularly in spring and summer. An ion fragment at m/z 75 is well correlated with the m/z 82 ion associated with the aerosol mass spectrum of IEPOX-derived secondary organic aerosol (SOA). The

  15. Inference of the aerosol Angstrom coefficient from SAGE short-wavelength data. [Stratospheric Aerosol and Gas Experiment

    NASA Technical Reports Server (NTRS)

    Lenoble, J.; Pruvost, P.

    1983-01-01

    SAGE four-channel transmission profiles are inverted to retrieve the extinction profiles from which the aerosol Angstrom coefficient alpha is obtained. The procedure allows one to check the influence of the NO2 absorption profile, which is small below 25 km. The results compare well with those obtained by a completely different procedure at NASA Langley Research Center, and the main features of the alpha profiles seem to be significant, even considering the rather large error bars. The relation between the retrieved Angstrom coefficient, the particle effective radius and the asymmetry factor is considered.

  16. Generation and characterization of condensation aerosols of benzo(a)pyrene

    SciTech Connect

    Tu, K.W.; Kanapilly, G.M.; Mitchell, C.E.

    1981-03-01

    Condensation aerosols of benzo(a)pyrene (BaP) with particle sizes ranging from 0.1 to 2 ..mu..m (aerodynamic diameter) were produced and studied. These aerosols were generated in a glove box by direct vaporization of BaP and homogeneous condensation of the vapor. The aerosol concentration ranged from 50 to 700 ..mu..g/l with aerosol production rates up to 15 mg BaP per minute. The effects of vaporization temperature and flow rate of diluting air on the particle size distribution and aerosol output were studied. The BaP aerosol was produced with relatively constant mass concentration and particle size distribution for more than 5 h. The aerosol was physicochemically and thermally stable. Data on the in vitro dissolution of BaP particles in aqueous solvents and in different dissolution systems suggested that the organic BaP particle does not dissolve in simple aqueous solvents.

  17. Clear Sky Column Closure Studies of Urban-Marine and Mineral-Dust Aerosols Using Aircraft, Ship, Satellite and Ground-Based Measurements in ACE-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Russell, Philip B.; Livingston, John M.; Gasso, Santiago; Hegg, Dean A.; Collins, Donald R.; Flagan, Richard C.; Seinfeld, John H.; Oestroem, Elisabeth; Noone, Kevin J.; Durkee, Philip A.; Jonsson, Haflidi H.; Welton, Ellsworth J.; Voss, Kenneth J.; Gordon, Howard R.; Formenti, Paola; Andreae, Meinrat O.; Kapustin, Vladimir N.; Bates, Timothy S.; Quinn, Patricia K.

    2000-01-01

    As part of the second Aerosol Characterization Experiment (ACE-2), European urban-marine and African mineral-dust aerosols were measured aboard the Pelican aircraft, the Research Vessel Vodyanitskiy from the ground and from satellites.

  18. Characterization of infectious aerosols in health care facilities: an aid to effective engineering controls and preventive strategies.

    PubMed

    Cole, E C; Cook, C E

    1998-08-01

    Assessment of strategies for engineering controls for the prevention of airborne infectious disease transmission to patients and to health care and related workers requires consideration of the factors relevant to aerosol characterization. These factors include aerosol generation, particle size and concentrations, organism viability, infectivity and virulence, airflow and climate, and environmental sampling and analysis. The major focus on attention to engineering controls comes from recent increases in tuberculosis, particularly the multidrug-resistant varieties in the general hospital population, the severely immunocompromised, and those in at-risk and confined environments such as prisons, long-term care facilities, and shelters for the homeless. Many workers are in close contact with persons who have active, undiagnosed, or insufficiently treated tuberculosis. Additionally, patients and health care workers may be exposed to a variety of pathogenic human viruses, opportunistic fungi, and bacteria. This report therefore focuses on the nature of infectious aerosol transmission in an attempt to determine which factors can be systematically addressed to result in proven, applied engineering approaches to the control of infectious aerosols in hospital and health care facility environments. The infectious aerosols of consideration are those that are generated as particles of respirable size by both human and environmental sources and that have the capability of remaining viable and airborne for extended periods in the indoor environment. This definition precludes skin and mucous membrane exposures occurring from splashes (rather than true aerosols) of blood or body fluids containing infectious disease agents. There are no epidemiologic or laboratory studies documenting the transmission of bloodborne virus by way of aerosols. PMID:9721404

  19. A model for the natural and anthropogenic aerosols over the tropical Indian Ocean derived from Indian Ocean Experiment data

    NASA Astrophysics Data System (ADS)

    Satheesh, S. K.; Ramanathan, V.; Li-Jones, Xu; Lobert, J. M.; Podgorny, I. A.; Prospero, J. M.; Holben, B. N.; Loeb, N. G.

    1999-11-01

    The physical, chemical and radiative properties of aerosols are investigated over the tropical Indian Ocean during the first field phase (FFP) of the international Indian Ocean Experiment. The FFP was conducted during February 20 to March 31, 1998. The results shown here are from the Kaashidhoo Climate Observatory (KCO), a new surface observatory established on the tiny island of Kaashidhoo (4.965°N, 73.466°E) in the Republic of Maldives. From simultaneous measurements of aerosol physical, chemical, and radiative properties and the vertical structure from lidar, we have developed an aerosol model which, in conjunction with a Monte Carlo radiative transfer model, successfully explains (within a few percent) the observed solar radiative fluxes at the surface and at the top of the atmosphere. This agreement demonstrates the fundamental importance of measuring aerosol physical and chemical properties for modeling radiative fluxes. KCO, during the northeast monsoon period considered here, is downwind of the Indian subcontinent and undergoes variations in the aerosol visible optical depth τν from ˜0.1 to 0.4, with a monthly mean of ˜0.2. Lidar data suggest that the aerosol is confined largely to the first 3 kms. Sulfate and ammonium contribute ˜29% to τν; sea-salt and nitrate contributes ˜17%; mineral dust contributes ˜15%; and the inferred soot, organics, and fly ash contribute 11%, 20%, and 8% respectively. We estimate that anthropogenic sources may contribute as much as 65% to the observed τν. We consider both an externally and an internally mixed aerosol model with very little difference between the two in the computed radiative forcing. The observed scattering coefficients are in the upper range of those reported for other oceanic regions, the single-scattering albedos are as low as 0.9, and the Angstrom wavelength exponents of ˜1.2 indicate the abundance of submicron aerosols. In summary, the data and the model confirm the large impact of

  20. Molecular Formula Characterization of Biogenic Secondary Organic Aerosol: Descriptive Statistical Evaluation

    NASA Astrophysics Data System (ADS)

    Dalbec, M.; Zhao, Y.; Fisseha, R.; Putman, A.; Kundu, S.; Rahn, T. A.; Mazzoleni, L. R.

    2013-12-01

    The detailed molecular composition of approximately 20 laboratory generated terpene ozonolysis secondary organic aerosol (SOA) samples was studied using ultrahigh resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Individual experiments were conducted with one of four terpene SOA precursors (α-pinene, β-pinene, limonene or β-caryophyllene), varied relative humidity (RH) conditions (0%, 4%, or 30%) and the presence or absence of cyclohexane (serving as a radical scavenger). In this work, we focus on the molecular composition of the SOA experiments conducted at 4% and 30% RH without cyclohexane. In each of the experimental SOA samples, the oxygen number and the DBE values increase with increasing carbon number and three or four distinct groups (aka oligomer groups) were observed in the mass spectra. The overall bulk properties, such as the elemental ratios and the average number of double bond equivalents (DBE), of the SOA were highly similar. Despite the high number of identified species (N ≥ 1000) in each SOA sample, compounds unique to the SOA formed at either 4% or 30% RH conditions were comparatively low (< 200). An exception to this was observed for the D-limonene ozonolysis SOA formed at 4% RH conditions where over 450 unique molecular formulas were observed. Due to the similarity in the bulk properties and composition of the SOA from the experiments, multivariate statistics were used to distinguish the experiments from each other. Hierarchical cluster analysis and principal component analysis was performed using the molecular formulas and their relative abundances for all of the identified species. Slight compositional differences between the experiments showed that experiments with the same terpene SOA precursor were most closely related regardless of the RH or the presence/absence of cyclohexane. Furthermore, SOA experiments with D-limonene and β-caryophyllene as precursors were clearly distinguished from β-pinene and

  1. In situ measurements of trace gases and aerosol optical properties at a rural site in northern China during East Asian Study of Tropospheric Aerosols: An International Regional Experiment 2005

    NASA Astrophysics Data System (ADS)

    Li, Can; Marufu, Lackson T.; Dickerson, Russell R.; Li, Zhanqing; Wen, Tianxue; Wang, Yuesi; Wang, Pucai; Chen, Hongbin; Stehr, Jeffrey W.

    2007-11-01

    In situ measurements of trace gases and aerosol optical properties were made in March 2005 at Xianghe (39.798°N, 116.958°E, 35 m), a rural site about 70 km southeast, and generally downwind of the Beijing metropolitan area. High pollutant levels were observed during the experiment, with CO (1.09 ± 1.02 ppmv, average ± standard deviation), SO2 (17.8 ± 15.7 ppbv), NOy (26.0 ± 24.0 ppbv), aerosol scattering coefficients (bsp, (468 ± 472) × 10-6 m-1), and aerosol absorption coefficients (bap, (65 ± 75) × 10-6 m-1) all much higher than observed at some rural sites in the United States. O3 (29.1 ± 16.5 ppbv) was relatively low during this study, suggesting inactive photochemical processes. Strong synoptic fluctuations in pollutant levels were detected every 4-5 days during the experiment, as cold fronts passing over the region drastically reduced the ground-level pollution. Very little precipitation was measured during the whole observational period, implying pollutant uplift and transport by rain-free cold fronts and dry convection. The single scattering albedo (SSA) observed (0.81 in the morning and 0.85 in the afternoon) indicates strongly absorbing aerosols near surface. The observed CO/SO2 ratio (35.8) is higher than inventory values, but closer to the updated CO inventory of Streets et al. (2006) than to Streets et al. (2003) or Wang et al. (2005). The observed CO/NOy ratio agrees better with inventories. Further analysis suggests that such comparisons may shed some light on the quality of emission inventories, but quantification of any error requires more extensive measurements over longer period and larger areas, as well as direct characterization of emission sources, especially mobile sources and small boilers. Using black carbon (BC)/CO ratio from the experiment, BC emissions from China are estimated at about 1300 Gg (109 g)/yr, but could be as high as 2600 Gg/yr.

  2. Dual carbon isotope characterization of total organic carbon in wintertime carbonaceous aerosols from northern India

    NASA Astrophysics Data System (ADS)

    Bikkina, Srinivas; Andersson, August; Sarin, M. M.; Sheesley, R. J.; Kirillova, E.; Rengarajan, R.; Sudheer, A. K.; Ram, K.; Gustafsson, Örjan

    2016-05-01

    Large-scale emissions of carbonaceous aerosols (CA) from South Asia impact both regional climate and air quality, yet their sources are not well constrained. Here we use source-diagnostic stable and radiocarbon isotopes (δ13C and Δ14C) to characterize CA sources at a semiurban site (Hisar: 29.2°N, 75.2°E) in the NW Indo-Gangetic Plain (IGP) and a remote high-altitude location in the Himalayan foothills (Manora Peak: 29.4°N, 79.5°E, 1950 m above sea level) in northern India during winter. The Δ14C of total aerosol organic carbon (TOC) varied from -178‰ to -63‰ at Hisar and from -198‰ to -1‰ at Manora Peak. The absence of significant differences in the 14C-based fraction biomass of TOC between Hisar (0.81 ± 0.03) and Manora Peak (0.82 ± 0.07) reveals that biomass burning/biogenic emissions (BBEs) are the dominant sources of CA at both sites. Combining this information with δ13C, other chemical tracers (K+/OC and SO42-/EC) and air mass back trajectory analyses indicate similar source regions in the IGP (e.g., Punjab and Haryana). These results highlight that CA from BBEs in the IGP are not only confined to the atmospheric boundary layer but also extend to higher elevations of the troposphere, where the synoptic-scale circulations could substantially influence their abundances both to the Himalayas and over the downwind oceanic regions such as the Indian Ocean. Given the vast emissions of CA from postharvest crop residue combustion practices in the IGP during early Northeast Monsoon, this information is important for both improved process and model understanding of climate and health effects, as well as in guiding policy decision aiming at reducing emissions.

  3. Characterization of inhalation aerosols: a critical evaluation of cascade impactor analysis and laser diffraction technique.

    PubMed

    de Boer, A H; Gjaltema, D; Hagedoorn, P; Frijlink, H W

    2002-12-01

    Cascade impactor analysis is the standard technique for in vitro characterization of aerosol clouds generated by medical aerosol generators. One important reason for using this inertial separation principle is that drug fractions are classified into aerodynamic size ranges that are relevant to the deposition in the respiratory tract. Measurement of these fractions with chemical detection methods enables establishment of the particle size distribution of the drug in the presence of excipients. However, the technique is laborious and time consuming and most of the devices used for inhaler evaluation lack sufficient possibilities for automation. In addition to that, impactors often have to be operated under conditions for which they were not designed and calibrated. Particularly, flow rates through impactors are increased to values at which the flow through the nozzles is highly turbulent. This has an uncontrolled influence on the collection efficiencies and cut-off curves of these nozzles. Moreover, the cut-off value varies with the flow rate through an impactor nozzle. On the other hand, the high air flow resistances of most impactors are rather restricting to the attainable (fixed) inspiratory flow curves through these devices. Especially for breath actuated dry powder inhalers, higher flow rates and flow increase rates may be desirable than can be achieved in combination with a particular type of impactor. In this paper, the applicability of laser diffraction technology is evaluated as a very fast and highly reliable alternative for cascade impactor analysis. With this technique, aerodynamic diameters cannot be measured, but for comparative evaluation and development, comprising most in vitro applications, this is not necessary. Laser diffraction has excellent possibilities for automated recording of data and testing conditions, and the size classes are independent of the flow rate. Practical limitations can be overcome by using a special inhaler adapter which

  4. SAGE ground truth plan: Correlative measurements for the Stratospheric Aerosol and Gas Experiment (SAGE) on the AEM-B satellite

    NASA Technical Reports Server (NTRS)

    Russell, P. B. (Editor); Cunnold, D. M.; Grams, G. W.; Laver, J.; Mccormick, M. P.; Mcmaster, L. R.; Murcray, D. G.; Pepin, T. J.; Perry, T. W.; Planet, W. G.

    1979-01-01

    The ground truth plan is outlined for correlative measurements to validate the Stratospheric Aerosol and Gas Experiment (SAGE) sensor data. SAGE will fly aboard the Applications Explorer Mission-B satellite scheduled for launch in early 1979 and measure stratospheric vertical profiles of aerosol, ozone, nitrogen dioxide, and molecular extinction between 79 N and 79 S. latitude. The plan gives details of the location and times for the simultaneous satellite/correlative measurements for the nominal launch time, the rationale and choice of the correlative sensors, their characteristics and expected accuracies, and the conversion of their data to extinction profiles. In addition, an overview of the SAGE expected instrument performance and data inversion results are presented. Various atmospheric models representative of stratospheric aerosols and ozone are used in the SAGE and correlative sensor analyses.

  5. Ozone and aerosol distributions measured by airborne lidar during the 1988 Arctic Boundary Layer Experiment

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Consideration is given to O3 and aerosol distributions measured from an aircraft using a DIAL system in order to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during summer 1988. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere.

  6. Retrieval of composition and size distribution of stratospheric aerosols with the SAGE II satellite experiment

    NASA Technical Reports Server (NTRS)

    Yue, Glenn K.; Mccormick, M. P.; Chu, W. P.

    1986-01-01

    The SAGE II satellite system was launched on October 5, 1984. It has seven radiometric channels and is beginning to provide water vapor, NO2, and O3 concentration profiles and aerosol extinction profiles at a minimum of three wavelengths. A simple, fast and operational method of retrieving characteristics of stratospheric aerosols from the water vapor and three-wavelength aerosol extinction profiles is proposed. Some examples are given to show the practicality of the scheme. Possible sources of error for the retrieved values and the limitation of the proposed method are discussed. This method may also prove applicable to the study of aerosol characteristics in other multispectral extinction measurements.

  7. Halogen Occultation Experiment (HALOE) optical filter characterization

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.

    1989-01-01

    The Halogen Occultation Experiment (HALOE) is a solar occultation experiment that will fly on the Upper Atmosphere Research Satellite to measure mixing ratio profiles of O3, H2O, NO2, NO, CH4, HCl, and HF. The inversion of the HALOE data will be critically dependent on a detailed knowledge of eight optical filters. A filter characterization program was undertaken to measure in-band transmissions, out-of-band transmissions, in-band transmission shifts with temperature, reflectivities, and age stability. Fourier Transform Infrared Spectrometers were used to perform measurements over the spectral interval 400/cm to 6300/cm (25 micrometers to 1.6 micrometers). Very high precision (0.1 percent T) in-band measurements and very high resolution (0.0001 percent T) out-of-band measurements have been made. The measurements revealed several conventional leaks at 0.01 percent transmission and greatly enhanced (1,000) leaks to the 2-element filters when placed in a Fabry-Perot cavity. Filter throughput changes by 5 percent for a 25 C change in filter temperature.

  8. Aerosol Models for the CALIPSO Lidar Inversion Algorithms

    NASA Technical Reports Server (NTRS)

    Omar, Ali H.; Winker, David M.; Won, Jae-Gwang

    2003-01-01

    We use measurements and models to develop aerosol models for use in the inversion algorithms for the Cloud Aerosol Lidar and Imager Pathfinder Spaceborne Observations (CALIPSO). Radiance measurements and inversions of the AErosol RObotic NETwork (AERONET1, 2) are used to group global atmospheric aerosols using optical and microphysical parameters. This study uses more than 105 records of radiance measurements, aerosol size distributions, and complex refractive indices to generate the optical properties of the aerosol at more 200 sites worldwide. These properties together with the radiance measurements are then classified using classical clustering methods to group the sites according to the type of aerosol with the greatest frequency of occurrence at each site. Six significant clusters are identified: desert dust, biomass burning, urban industrial pollution, rural background, marine, and dirty pollution. Three of these are used in the CALIPSO aerosol models to characterize desert dust, biomass burning, and polluted continental aerosols. The CALIPSO aerosol model also uses the coarse mode of desert dust and the fine mode of biomass burning to build a polluted dust model. For marine aerosol, the CALIPSO aerosol model uses measurements from the SEAS experiment 3. In addition to categorizing the aerosol types, the cluster analysis provides all the column optical and microphysical properties for each cluster.

  9. Premonsoon Aerosol Characterization and Radiative Effects Over the Indo-Gangetic Plains: Implications for Regional Climate Warming

    NASA Technical Reports Server (NTRS)

    Gautam, Ritesh; Hsu, N. Christina; Lau, K.-M.

    2010-01-01

    The Himalayas have a profound effect on the South Asian climate and the regional hydrological cycle, as it forms a barrier for the strong monsoon winds and serves as an elevated heat source, thus controlling the onset and distribution of precipitation during the Indian summer monsoon. Recent studies have suggested that radiative heating by absorbing aerosols, such as dust and black carbon over the Indo-Gangetic Plains (IGP) and slopes of the Himalayas, may significantly accelerate the seasonal warming of the Hindu Kush-Himalayas-Tibetan Plateau (HKHT) and influence the subsequent evolution of the summer monsoon. This paper presents a detailed characterization of aerosols over the IGP and their radiative effects during the premonsoon season (April-May-June) when dust transport constitutes the bulk of the regional aerosol loading, using ground radiometric and spaceborne observations. During the dust-laden period, there is a strong response of surface shortwave flux to aerosol absorption indicated by the diurnally averaged forcing efficiency of -70 W/sq m per unit optical depth. The simulated aerosol single-scattering albedo, constrained by surface flux and aerosol measurements, is estimated to be 0.89+/- 0.01 (at approx.550 nm) with diurnal mean surface and top-of-atmosphere forcing values ranging from -11 to -79.8 W/sq m and +1.4 to +12 W/sq m, respectively, for the premonsoon period. The model-simulated solar heating rate profile peaks in the lower troposphere with enhanced heating penetrating into the middle troposphere (5-6 km), caused by vertically extended aerosols over the IGP with peak altitude of approx.5 km as indicated by spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization observations. On a long-term climate scale, our analysis, on the basis of microwave satellite measurements of tropospheric temperatures from 1979 to 2007, indicates accelerated annual mean warming rates found over the Himalayan-Hindu Kush region (0.21 C/decade+/-0.08 C

  10. A System to Create Stable Nanoparticle Aerosols from Nanopowders.

    PubMed

    Ding, Yaobo; Riediker, Michael

    2016-01-01

    Nanoparticle aerosols released from nanopowders in workplaces are associated with human exposure and health risks. We developed a novel system, requiring minimal amounts of test materials (min. 200 mg), for studying powder aerosolization behavior and aerosol properties. The aerosolization procedure follows the concept of the fluidized-bed process, but occurs in the modified volume of a V-shaped aerosol generator. The airborne particle number concentration is adjustable by controlling the air flow rate. The system supplied stable aerosol generation rates and particle size distributions over long periods (0.5-2 hr and possibly longer), which are important, for example, to study aerosol behavior, but also for toxicological studies. Strict adherence to the operating procedures during the aerosolization experiments ensures the generation of reproducible test results. The critical steps in the standard protocol are the preparation of the material and setup, and the aerosolization operations themselves. The system can be used for experiments requiring stable aerosol concentrations and may also be an alternative method for testing dustiness. The controlled aerosolization made possible with this setup occurs using energy inputs (may be characterized by aerosolization air velocity) that are within the ranges commonly found in occupational environments where nanomaterial powders are handled. This setup and its operating protocol are thus helpful for human exposure and risk assessment. PMID:27501179

  11. The FLAME Deluge: organic aerosol emission ratios from combustion chamber experiments

    NASA Astrophysics Data System (ADS)

    Jolleys, Matthew; Coe, Hugh; McFiggans, Gordon; McMeeking, Gavin; Lee, Taehyoung; Sullivan, Amy; Kreidenweis, Sonia; Collett, Jeff

    2014-05-01

    A high level of variability has been identified amongst organic aerosol (OA) emission ratios (ER) from biomass burning (BB) under ambient conditions. However, it is difficult to assess the influences of potential drivers for this variability, given the wide range of conditions associated with wildfire measurements. Chamber experiments performed under controlled conditions provide a means of examining the effects of different fuel types and combustion conditions on OA emissions from biomass fuels. ERs have been characterised for 67 burns during the second Fire Laboratory at Missoula Experiment (FLAME II), involving 19 different species from 6 fuel types widely consumed in BB events in the US each year. Average normalised dOA/dCO ratios show a high degree of variability, both between and within different fuel types and species, typically exceeding variability between separate plumes in ambient measurements. Relationships with source conditions were found to be complex, with little consistent influence from fuel properties and combustion conditions for the entire range of experiments. No strong correlation across all fires was observed between dOA/dCO and modified combustion efficiency (MCE), which is used as an indicator of the proportional contributions of flaming and smouldering combustion phases throughout each burn. However, a negative correlation exists between dOA/dCO and MCE for some coniferous species, most notably Douglas fir, for which there is also an apparent influence from fuel moisture content. Significant contrasts were also identified between combustion emissions from different fuel components of additional coniferous species. Changes in fire efficiency were also shown to dramatically alter emissions for fires with very similar initial conditions. Although the relationship with MCE is variable between species, there is greater consistency with the level of oxygenation in OA. The ratio of the m/z 44 fragment to total OA mass concentration (f44) as

  12. Atmospheric aerosol monitoring and characterization: An emission control strategy to protect tropical forests

    NASA Astrophysics Data System (ADS)

    Mateus, V. L.; do Valles, T. V.; de Oliveira, T. B.; de Almeida, A. C.; Maia, L. F. P. G.; Saint'Pierre, T. D.; Gioda, A.

    2013-12-01

    .87) than at Flonamax (r = 0.46), suggesting a marked anthropogenic influence in the former. WSOC and nss-SO42- showed a moderate correlation ( r = 0.3-0.5) at both sites suggesting secondary aerosol formation. The dissimilarity between the areas regarding to water-soluble species are probably due to the particle size. However, both sites are influenced by highways, which, at first glance, is the highest anthropogenic input. In the conference, we will provide more data related to chemical characterization as well as the enrichment factor (EF) and principal component analysis (PCA), to better understand the source apportionment.

  13. Characterization of the Source Physics Experiment Site

    NASA Astrophysics Data System (ADS)

    Sussman, A. J.; Schultz-Fellenz, E. S.; Broome, S. T.; Townsend, M.; Abbott, R. E.; Snelson, C. M.; Cogbill, A. H.; Conklin, G.; Mitra, G.; Sabbeth, L.

    2012-12-01

    Designed to improve long-range treaty monitoring capabilities, the Source Physics Experiments, conducted at the Nevada National Security Site, also provide an opportunity to advance near-field monitoring and field-based investigations of suspected underground test locations. In particular, features associated with underground testing can be evaluated using Source Physics Experiment activities as analogs, linking on-site inspections with remote sensing technologies. Following a calibration shot (SPE 1), SPE 2 (10/2011) and SPE 3 (07/2012) were performed in the same emplacement hole with 1.0 ton of explosives at 150 ft depth. Because one of the goals of the Source Physics Experiments is to determine damage effects on seismic wave propagation and improve modeling capabilities, a key component in the predictive component and ultimate validation of the models is a full understanding of the intervening geology between the source and instrumented bore holes. Ground-based LIDAR and fracture mapping, mechanical properties determined via laboratory testing of rock core, discontinuity analysis and optical microscopy of the core rocks were performed prior to and following each experiment. In addition, gravity and magnetic data were collected between SPE 2 and 3. The source region of the explosions was also characterized using cross-borehole seismic tomography and vertical seismic profiling utilizing two sets of two boreholes within 40 meters of ground zero. The two sets of boreholes are co-linear with the explosives hole in two directions. Results of the LIDAR collects from both SPE 2 and 3 indicate a permanent ground displacement of up to several centimeters aligning along the projected surface traces of two faults observed in the core and fractures mapped at the surface. Laboratory testing and optical work show a difference in the characteristics of the rocks below and above 40 feet and within the fault zones.The estimated near-surface densities from the gravity survey show

  14. Tropospheric water vapor and aerosol measurements obtained during LASE validation experiment

    SciTech Connect

    Browell, E.V.; Ismail, S.; Hall, W.M.; Moore, A.S.

    1996-10-01

    The Lidar Atmospheric Sensing Experiment (LASE) is a Differential Absorption Lidar (DIAL) system flown on the NASA ER-2 aircraft to remotely measure distributions of tropospheric water vapor, aerosols, and clouds. LASE was developed at the NASA Langley Research Center (LaRC) to demonstrate autonomous operation of a DIAL system from a high-altitude aircraft as an important step towards developing a spaceborne DIAL system. LASE uses a double pulsed Ti:sapphire laser operating in the 815-nm absorption band of water vapor to generate the on- and off-line DIAL laser pulses. The system has two avalanche photodiode detectors and three signal digitizers to preserve the lidar backscatter signals over a large dynamic range. In September 1995, LASE completed a comprehensive validation program at the NASA Wallops Flight Facility. The system was flown on the ER-2 during ten flights for a total of 60 hours. LASE measurements of tropospheric water vapor were compared with other remote and in situ measurements of water vapor from the ground and from aircraft which underflew the ER-2. Besides making intercomparisons with a number of water vapor sensors, this experiment incorporated a number of case studies related to atmospheric events including flights over and around Hurricane Luis over the Atlantic ocean, sea breeze development along the east coast of Virginia, and stratosphere-troposphere exchange. This paper presents data taken during this field experiment that demonstrate the accuracy of LASE for tropospheric water vapor measurements. The paper also discusses results from several of the atmospheric case studies conducted during this experiment and the potential future uses of LASE.

  15. A global aerosol classification algorithm incorporating multiple satellite data sets of aerosol and trace gas abundances

    NASA Astrophysics Data System (ADS)

    Penning de Vries, M. J. M.; Beirle, S.; Hörmann, C.; Kaiser, J. W.; Stammes, P.; Tilstra, L. G.; Tuinder, O. N. E.; Wagner, T.

    2015-09-01

    Detecting the optical properties of aerosols using passive satellite-borne measurements alone is a difficult task due to the broadband effect of aerosols on the measured spectra and the influences of surface and cloud reflection. We present another approach to determine aerosol type, namely by studying the relationship of aerosol optical depth (AOD) with trace gas abundance, aerosol absorption, and mean aerosol size. Our new Global Aerosol Classification Algorithm, GACA, examines relationships between aerosol properties (AOD and extinction Ångström exponent from the Moderate Resolution Imaging Spectroradiometer (MODIS), UV Aerosol Index from the second Global Ozone Monitoring Experiment, GOME-2) and trace gas column densities (NO2, HCHO, SO2 from GOME-2, and CO from MOPITT, the Measurements of Pollution in the Troposphere instrument) on a monthly mean basis. First, aerosol types are separated based on size (Ångström exponent) and absorption (UV Aerosol Index), then the dominating sources are identified based on mean trace gas columns and their correlation with AOD. In this way, global maps of dominant aerosol type and main source type are constructed for each season and compared with maps of aerosol composition from the global MACC (Monitoring Atmospheric Composition and Climate) model. Although GACA cannot correctly characterize transported or mixed aerosols, GACA and MACC show good agreement regarding the global seasonal cycle, particularly for urban/industrial aerosols. The seasonal cycles of both aerosol type and source are also studied in more detail for selected 5° × 5° regions. Again, good agreement between GACA and MACC is found for all regions, but some systematic differences become apparent: the variability of aerosol composition (yearly and/or seasonal) is often not well captured by MACC, the amount of mineral dust outside of the dust belt appears to be overestimated, and the abundance of secondary organic aerosols is underestimated in comparison

  16. Characterizing the influence of anthropogenic emissions and transport variability on sulfate aerosol concentrations at Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Potter, Lauren E.

    Sulfate aerosol in the atmosphere has substantial impacts on human health and environmental quality. Most notably, atmospheric sulfate has the potential to modify the earth's climate system through both direct and indirect radiative forcing mechanisms (Meehl et al., 2007). Emissions of sulfur dioxide, the primary precursor of sulfate aerosol, are now globally dominated by anthropogenic sources as a result of widespread fossil fuel combustion. Economic development in Asian countries since 1990 has contributed considerably to atmospheric sulfur loading, particularly China, which currently emits approximately 1/3 of global anthropogenic SO2 (Klimont et al., 2013). Observational and modeling studies have confirmed that anthropogenic pollutants from Asian sources can be transported long distances with important implications for future air quality and global climate change. Located in the remote Pacific Ocean (19.54°N, 155.58°W) at an elevation of 3.4 kilometers above sea level, Mauna Loa Observatory (MLO) is an ideal measurement site for ground-based, free tropospheric observations and is well situated to experience influence from springtime Asian outflow. This study makes use of a 14-year data set of aerosol ionic composition, obtained at MLO by the University of Hawaii at Manoa. Daily filter samples of total aerosol concentrations were made during nighttime downslope (free-tropospheric) transport conditions, from 1995 to 2008, and were analyzed for aerosol-phase concentrations of the following species: nitrate (NO3-), sulfate (SO42-), methanesulfonate (MSA), chloride (Cl-), oxalate, sodium (Na+), ammonium (NH 4+), potassium (K+), magnesium (Mg 2+), and calcium (Ca2+). An understanding of the factors controlling seasonal and interannual variations in aerosol speciation and concentrations at this site is complicated by the relatively short lifetimes of aerosols, compared with greenhouse gases which have also been sampled over long time periods at MLO. Aerosol filter

  17. Development and Use of Particle into Liquid Sampling Time-of-Flight Mass Spectrometry (PILS-ToF) for Characterization of Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Clark, Christopher Holmes

    This dissertation introduces and makes use of the Particle-into-Liquid-Sampler coupled to a Time-of-Flight mass spectrometer (PILS-ToF), a new instrumental method used here to provide new chemical characterization information on secondary organic aerosol (SOA). The PILS-ToF instrument improves upon drawbacks found in current state-of-the-art mass spectral chemical characterization methods to include lack of time resolution and ion fragmentation by electron impact ionization in the Aerodyne Aerosol Mass Spectrometer (AMS). The functionality of the PILS-ToF for collection and response to SOA particle formation is validated against a scanning mobility particle sizer (SMPS), a widely accepted and standardized physical chemical characterization instrument, for a well characterized SOA formation experiment, dark ozonolysis of α-pinene. The PILS-ToF is also used to lend insight into oligomer growth during the NO photo-oxidation of isoprene. It is of atmospheric importance to study SOA formation from isoprene as it is globally the most abundant non-methane hydrocarbon in the ambient. SOA from isoprene is further studied using the PILS-ToF as part of the suite instrumentation at the University of California, Riverside, College of Engineering, Center for Environmental Research and Technology (CE-CERT) atmospheric chamber providing a complete chemical and physical characterization of SOA formed by isoprene with various oxidants under a myriad of oxidant concentration conditions. In addition, the PILS-ToF is used, again in tandem with other chemical and physical characterization methods at CE-CERT, to probe temperature effects on SOA formation from isoprene under many different oxidizing conditions. Finally, the PILS-ToF is used to provide new mechanistic information on SOA formation from trimethylamine and tributylamine, two tertiary amines emitted from anthropogenic and animal husbandry processes. For these two teriary amines the PILS-ToF provides evidence of

  18. ABOVE03, The 2003 AIRS BBAERI Ocean Validation Experiment: AIRS Validation and Aerosols

    NASA Astrophysics Data System (ADS)

    McMillan, W. W.; Hoff, R.; Strow, L. L.; Desouza-Machado, S.; Lightner, K.; McCourt, M. L.; Maddy, E.; Kolb, N.; McCann, K.; Comer, J.; Russo, F.; Rutledge, C. K.

    2003-12-01

    From May 28 to July 9, 2003, a complementary set of instruments was deployed to the United States Coast Guard (USCG) Chesapeake Light lighthouse platform to provide correlative measurements characterizing the atmosphere and sea surface over the ocean for validation of NASA's Atmospheric InfraRed Sounder (AIRS) onboard the Aqua satellite. Located 25 km due east of Virginia Beach, VA, Chesapeake Light offers a relatively convenient site for measurements over the ocean while being far enough offshore for water only AIRS fields of view. In addition to the UMBC Baltimore Bomem Atmospheric Emitted Radiance Interferometer (BBAERI), the UMBC Elastic Lidar Facility (ELF), and Vaisala RS-90 rawinsondes used during ABOVE02, we deployed in situ O3 and CO gas analyzers and during the first three weeks, flew 18 ozonesondes in collaboration with Dr. Mike Newchurch, UAH. A total of 140 Vaisala RS-90 radiosondes were launched covering 61 Aqua and 12 Terra overpasses. Preliminary comparisons of ABOVE03 data products to AIRS observations and retrievals will be presented. Particular attention will be paid to both AIRS and ground-based aerosol observations.

  19. Using Single-Scattering Albedo Spectral Curvature to Characterize East Asian Aerosol Mixtures

    NASA Technical Reports Server (NTRS)

    Li, Jing; Carlson, Barbara E.; Lacis, Andrew A.

    2015-01-01

    Spectral dependence of aerosol single-scattering albedo (SSA) has been used to infer aerosol composition. In particular, aerosol mixtures dominated by dust absorption will have monotonically increasing SSA with wavelength while that dominated by black carbon absorption has monotonically decreasing SSA spectra. However, by analyzing SSA measured at four wavelengths, 440, 675, 870, and 1020 nm from the Aerosol Robotic Network data set, we find that the SSA spectra over East Asia are frequently peaked at 675 nm. In these cases, we suggest that SSA spectral curvature, defined as the negative of the second derivative of SSA as a function of wavelength, can provide additional information on the composition of these aerosol mixtures. Aerosol SSA spectral curvatures for East Asia during fall and winter are considerably larger than those found in places primarily dominated by biomass burning or dust aerosols. SSA curvature is found to increase as the SSA magnitude decreases. The curvature increases with coarse mode fraction (CMF) to a CMF value of about 0.4, then slightly decreases or remains constant at larger CMF. Mie calculations further verify that the strongest SSA curvature occurs at approx. 40% dust fraction, with 10% scattering aerosol fraction. The nonmonotonic SSA spectral dependence is likely associated with enhanced absorption in the shortwave by dust, absorption by black carbon at longer wavelengths, and also the flattened absorption optical depth spectral dependence due to the increased particle size.

  20. Characterization of the seasonal cycle of south Asian aerosols: A Regional-Scale Modeling Analysis.

    SciTech Connect

    Adhikary, Bhupesh; Carmichael, Gregory; Tang, Youhua; Leung, Lai-Yung R.; Qian, Yun; Schauer, James J.; Stone, Elizabeth A.; Ramanathan, Veerabhadran; Ramana, Muvva V.

    2007-11-07

    The STEM chemical transport model is used to study the aerosol distribution, composition and seasonality over South Asia from September 2004 to August 2005. Model predictions of sulfate, black carbon, primary organic carbon, other anthropogenic particulate matter, wind blown mineral dusts and sea salt are compared at two sites in South Asia where year long experimental observations are available from the Atmospheric Brown Cloud (ABC) Project. The model predictions are able to capture both the magnitude and seasonality of aerosols over Hanimaadhoo Observatory, Maldives. However, the model is not able to explain the seasonality at the Kathmandu Observatory; but the model does capture Kathmandu’s observed annual mean concentration. The absence of seasonal brick kiln emissions within Kathmandu valley in the current inventory is a probable reason for this problem. This model study reveals high anthropogenic aerosol loading over the Ganges valley even in the monsoonal months, which needs to be corroborated by experimental observations. Modeling results also show a high dust loading over South Asia with a distinct seasonality. Model results of aerosol monthly composition are also presented at 5 cities in South Asia. Total and fine mode aerosol optical depth along with contribution from each aerosol species is presented; the results show that the anthropogenic fraction dominates in the dry season with major contributions from sulfate and absorbing aerosols. Finally comparison with observations show that model improvements are needed in the treatment of aerosol dry and wet removal processes and increase in sulfate production via heterogeneous pathways.

  1. MODIS Satellite Data and GOCART Model Characterization of the Global Aerosol

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram; Chin, Mian; Remer, Lorraine; Tanre, Didier; Lau, William K.-M. (Technical Monitor)

    2003-01-01

    Recently produced daily MODIS aerosol data for the whole year of 2001 are used to show the concentration and dynamics of aerosol over ocean and large parts of the continents. The data were validated against the Aerosol Robotic Network (AERONET) measurements over land and ocean. Monthly averages and a movie based on the daily data are produced and used to demonstrate the spatial and temporal evolution of aerosol. The MODIS wide spectral range is used to distinguish fine smoke and pollution aerosol from coarse dust and salt. The aerosol is observed above ocean and land. The movie produced from the MODIS data provides a new dimension to aerosol observations by showing the dynamics of the system. For example in February smoke and dust emitted from the Sahel and West Africa is shown to travel to the North-East Atlantic. In April heavy dust and pollution from East Asia is shown to travel to North America. In May-June pollution and dust play a dynamical dance in the Arabian Sea and Bay of Bengal. In Aug-September smoke from South Africa and South America is shown to pulsate in tandem and to periodically to be transported to the otherwise pristine Southern part of the Southern Hemisphere. The MODIS data are compared with the GOCART model and used to estimate the first observation based direct anthropogenic radiative forcing of climate by aerosol.

  2. Aerosol characteristics over Bay of Bengal during winter: Results from W-ICARB experiment

    NASA Astrophysics Data System (ADS)

    Sinha, P. R.; Manchanda, R. K.; Shankarnarayan, Sreenivasan; Babu, S. Suresh; Krishna Moorthy, K.; Kaskaoutis, D. G.

    2012-07-01

    The measurements of aerosol physical optical properties were carried out over placeBay of Bengal (BoB) during the period 27 December 2008--30 January 2009 as part of Winter Integrated Campaign on Aerosols, Gases and Radiation Budget (W-ICARB). The aerosol number size distribution at the surface was found to be bi-modal in the 72% of the cases with mode radius for the submicron aerosol of 0.13±0.01 μ m and 0.72±0.10μ m for the super-micron aerosol and the highest NT (350-550 cm{-3}), AOD500 (0.7}) and α 380-870 values were observed in western and northern BoB with lower values in the southern and parts of central BoB. The eastern part of BoB which was investigated for the first time showed concurrently high values of NT (200 and 300 cm-3), AOD500 (0.39±0.07) and α 380-870 (1.27±0.09). The aerosol types are examined using a classification scheme based on the relationship between aerosol load (AOD500) and particle size (α 380-870). The classification scheme indicated an extremely large fraction of fine-mode aerosols in turbid atmospheres, which is even larger than 90% in the western part of BoB and approaches 100% over eastern BoB. Furthermore, there is also an evidence of aerosol-size growth under more turbid conditions indicative of coagulation and/or humidification over specific BoB regions. The altitude variation of aerosol number density made for the first time over five different locations in BoB is found to be nearly steady at all locations within the convective boundary layer (up to 400 m), while above the aerosol concentration is found to decrease except for far east BoB. Examination of the air-mass back trajectories and the aerosol size distribution indicates that the aerosols advected from continental country-regionIndia have a pronounced natural (coarse mode) component, while those originating from placeEast Asia are in general accumulation origin.

  3. An overview of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx)

    NASA Astrophysics Data System (ADS)

    Dulac, François

    2014-05-01

    The Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr) is a French initiative of the MISTRALS meta-programme (Mediterranean Integrated Studies at Regional And Locals Scales, http://www.mistrals-home.org). It federates a great number of national and international cooperative research actions aiming at a scientific assessment of the present and future state of the atmospheric environment in the Mediterranean Basin, and of its impacts on the regional climate, air quality, and marine biogeochemistry. The target is short-lived particulate and gaseous tropospheric trace species which are the cause of poor air quality events, have two-way interactions with climate, or impact the marine biogeochemistry, in a context of strong regional anthropogenic and climatic pressures. The six ChArMEx work packages include Emissions, Chemical processes and ageing, Transport processes and air quality, Aerosol-radiation-climate interactions, Deposition, and Present and future variability and trends. For several years, efforts have been deployed in several countries to develop (i) a network of relevant stations for atmospheric chemistry at background sites on islands and continental coasts around the basin and (ii) several intensive field campaigns including the operation of surface supersites and various instrumented mobile platforms (large and ultra-light aircraft, sounding and drifting balloons, ZeroCO2 sailboat). This presentation is an attempt to provide an overview of the various experimental, remote sensing and modelling efforts produced and to highlight major findings, by referencing more detailed ChArMEx presentations given in this conference and recently published or submitted papers. During the first phase of the project experimental efforts have been mainly concentrated on the western basin. Plans for the 2nd phase of ChArMEx, more dedicated towards the eastern basin, will also be given. In particular we plan to develop monitoring activities at

  4. A three-dimensional characterization of Arctic aerosols from airborne Sun photometer observations: PAM-ARCMIP, April 2009

    NASA Astrophysics Data System (ADS)

    Stone, R. S.; Herber, A.; Vitale, V.; Mazzola, M.; Lupi, A.; Schnell, R. C.; Dutton, E. G.; Liu, P. S. K.; Li, S.-M.; Dethloff, K.; Lampert, A.; Ritter, C.; Stock, M.; Neuber, R.; Maturilli, M.

    2010-07-01

    The Arctic climate is modulated, in part, by atmospheric aerosols that affect the distribution of radiant energy passing through the atmosphere. Aerosols affect the surface-atmosphere radiation balance directly through interactions with solar and terrestrial radiation and indirectly through interactions with cloud particles. Better quantification of the radiative forcing by different types of aerosol is needed to improve predictions of future climate. During April 2009, the airborne campaign Pan-Arctic Measurements and Arctic Regional Climate Model Inter-comparison Project (PAM-ARCMIP) was conducted. The mission was organized by Alfred Wegener Institute for Polar and Marine Research of Germany and utilized their research aircraft, Polar-5. The goal was to obtain a snapshot of surface and atmospheric conditions over the central Arctic prior to the onset of the melt season. Characterizing aerosols was one objective of the campaign. Standard Sun photometric procedures were adopted to quantify aerosol optical depth AOD, providing a three-dimensional view of the aerosol, which was primarily haze from anthropogenic sources. Independent, in situ measurements of particle size distribution and light extinction, derived from airborne lidar, are used to corroborate inferences made using the AOD results. During April 2009, from the European to the Alaskan Arctic, from sub-Arctic latitudes to near the pole, the atmosphere was variably hazy with total column AOD at 500 nm ranging from ˜0.12 to >0.35, values that are anomalously high compared with previous years. The haze, transported primarily from Eurasian industrial regions, was concentrated within and just above the surface-based temperature inversion layer. Extinction, as measured using an onboard lidar system, was also greatest at low levels, where particles tended to be slightly larger than at upper levels. Black carbon (BC) (soot) was observed at all levels sampled, but at moderate to low concentrations compared with

  5. Characterization of indoor aerosol temporal variations for the real-time management of indoor air quality

    NASA Astrophysics Data System (ADS)

    Ciuzas, Darius; Prasauskas, Tadas; Krugly, Edvinas; Sidaraviciute, Ruta; Jurelionis, Andrius; Seduikyte, Lina; Kauneliene, Violeta; Wierzbicka, Aneta; Martuzevicius, Dainius

    2015-10-01

    The study presents the characterization of dynamic patterns of indoor particulate matter (PM) during various pollution episodes for real-time IAQ management. The variation of PM concentrations was assessed for 20 indoor activities, including cooking related sources, other thermal sources, personal care and household products. The pollution episodes were modelled in full-scale test chamber representing a standard usual living room with the forced ventilation of 0.5 h-1. In most of the pollution episodes, the maximum concentration of particles in exhaust air was reached within a few minutes. The most rapid increase in particle concentration was during thermal source episodes such as candle, cigarette, incense stick burning and cooking related sources, while the slowest decay of concentrations was associated with sources, emitting ultrafine particle precursors, such as furniture polisher spraying, floor wet mopping with detergent etc. Placement of the particle sensors in the ventilation exhaust vs. in the centre of the ceiling yielded comparable results for both measured maximum concentrations and temporal variations, indicating that both locations were suitable for the placement of sensors for the management of IAQ. The obtained data provides information that may be utilized considering measurements of aerosol particles as indicators for the real-time management of IAQ.

  6. Characterization of biological aerosol exposure risks from automobile air conditioning system.

    PubMed

    Li, Jing; Li, Mingzhen; Shen, Fangxia; Zou, Zhuanglei; Yao, Maosheng; Wu, Chang-yu

    2013-09-17

    Although use of automobile air conditioning (AC) was shown to reduce in-vehicle particle levels, the characterization of its microbial aerosol exposure risks is lacking. Here, both AC and engine filter dust samples were collected from 30 automobiles in four different geographical locations in China. Biological contents (bacteria, fungi, and endotoxin) were studied using culturing, high-throughput gene sequence, and Limulus amebocyte lysate (LAL) methods. In-vehicle viable bioaerosol concentrations were directly monitored using an ultraviolet aerodynamic particle sizer (UVAPS) before and after use of AC for 5, 10, and 15 min. Regardless of locations, the vehicle AC filter dusts were found to be laden with high levels of bacteria (up to 26,150 CFU/mg), fungi (up to 1287 CFU/mg), and endotoxin (up to 5527 EU/mg). More than 400 unique bacterial species, including human opportunistic pathogens, were detected in the filter dusts. In addition, allergenic fungal species were also found abundant. Surprisingly, unexpected fluorescent peaks around 2.5 μm were observed during the first 5 min use of AC, which was attributed to the reaerosolization of those filter-borne microbial agents. The information obtained here can assist in minimizing or preventing the respiratory allergy or infection risk from the use of automobile AC system.

  7. Airborne Fungi in Sahara Dust Aerosols Reaching the Eastern Caribbean: I. Taxonomic Characterization by Morphological Features

    NASA Astrophysics Data System (ADS)

    Rivera-Denizard, O.; Betancourt, C.; Armstrong, R. A.; Detres, Y.

    2003-12-01

    A wide variety of microorganisms are dispersed into the Caribbean region due to the input of Saharan dust aerosols during the summer months. These microorganisms can cause diseases in plants and animals, and might be responsible for an increase incidence of asthma and respiratory diseases in this region. A PM 2.5 air sampling station was installed in Castle Bruce, Dominica from March through July of 2002. Fourteen filters were obtained by running the air sampler continuously for 24 hour periods. The samples were collected in sterile Teflon filters (47 mm in diameter, 0.2 um pore size), inoculated in Malt Extract Agar (MEA) with lactic acid and incubated at 29° C. Colonies were counted, isolated and cultured on separate Petri dishes. Fungal classification to the genus level used macroscopic features and microscopic evaluation. The Nomarski light microscopy technique was used for identification of reproductive structures. A total of 105 colonies were isolated. Six genera including Aspergillus, Penicillium, Cladosporium, Fusarium, Curvularia,and Nigrospora were identified. The protocol for the molecular characterization to species level is presented as the second part of this work.

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

    NASA Astrophysics Data System (ADS)

    Baltensperger, Urs

    2015-03-01

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

  9. Characterization of a real-time tracer for isoprene epoxydiols-derived secondary organic aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

    NASA Astrophysics Data System (ADS)

    Hu, W. W.; Campuzano-Jost, P.; Palm, B. B.; Day, D. A.; Ortega, A. M.; Hayes, P. L.; Krechmer, J. E.; Chen, Q.; Kuwata, M.; Liu, Y. J.; de Sá, S. S.; McKinney, K.; Martin, S. T.; Hu, M.; Budisulistiorini, S. H.; Riva, M.; Surratt, J. D.; St. Clair, J. M.; Isaacman-Van Wertz, G.; Yee, L. D.; Goldstein, A. H.; Carbone, S.; Brito, J.; Artaxo, P.; de Gouw, J. A.; Koss, A.; Wisthaler, A.; Mikoviny, T.; Karl, T.; Kaser, L.; Jud, W.; Hansel, A.; Docherty, K. S.; Alexander, M. L.; Robinson, N. H.; Coe, H.; Allan, J. D.; Canagaratna, M. R.; Paulot, F.; Jimenez, J. L.

    2015-10-01

    large variations in its detailed molecular composition. The low fC5H6O (< 3 ‰) reported in non-IEPOX-derived isoprene-SOA from chamber studies indicates that this tracer ion is specifically enhanced from IEPOX-SOA, and is not a tracer for all SOA from isoprene. We introduce a graphical diagnostic to study the presence and aging of IEPOX-SOA as a triangle plot of fCO2 vs. fC5H6O. Finally, we develop a simplified method to estimate ambient IEPOX-SOA mass concentrations, which is shown to perform well compared to the full PMF method. The uncertainty of the tracer method is up to a factor of ~ 2, if the fC5H6O of the local IEPOX-SOA is not available. When only unit mass-resolution data are available, as with the aerosol chemical speciation monitor (ACSM), all methods may perform less well because of increased interferences from other ions at m/z 82. This study clarifies the strengths and limitations of the different AMS methods for detection of IEPOX-SOA and will enable improved characterization of this OA component.

  10. Seasonal characterization of submicron aerosol chemical composition and organic aerosol sources in the southeastern United States: Atlanta, Georgia and Look Rock, Tennessee

    NASA Astrophysics Data System (ADS)

    Budisulistiorini, S. H.; Baumann, K.; Edgerton, E. S.; Bairai, S. T.; Mueller, S.; Shaw, S. L.; Knipping, E. M.; Gold, A.; Surratt, J. D.

    2015-08-01

    A yearlong near-real-time characterization of non-refractory submicron aerosol (NR-PM1) was conducted at an urban (Atlanta, Georgia) and rural (Look Rock, Tennessee) site in the southeastern US using the Aerodyne aerosol chemical speciation monitor (ACSM) collocated with established air-monitoring network measurements. Seasonal variations in organic aerosol (OA) and inorganic aerosol species are attributed to meteorological conditions as well as anthropogenic and biogenic emissions in this region. The highest concentrations of NR-PM1 were observed during winter and fall seasons at the urban site and during spring and summer at the rural site. Across all seasons and at both sites, NR-PM1 was composed largely of OA (50-76 %) and inorganic sulfate (12-31 %). Six distinct OA sources were resolved by positive matrix factorization applied to the ACSM organic mass spectral data collected from the two sites over the one year of near-continuous measurements at each site: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), semi-volatile oxygenated OA (SV-OOA), low-volatility oxygenated OA (OOA), isoprene-derived epoxydiol (IEPOX) OA (IEPOX-OA), and 91Fac OA (a factor dominated by a distinct ion at m/z 91 fragment ion previously observed in biogenic influenced areas). LV-OOA was observed throughout the year at both sites and contributed 30-66 % of total OA mass. HOA was also observed during the entire year only at the urban site (15-24 % of OA mass). BBOA (15-33 % of OA mass) was observed during winter and fall, likely dominated by local residential wood burning emission. Although SV-OOA contributes quite significantly (∼ 27 %), it was observed only at the urban site during colder seasons. IEPOX-OA was a major component (27-41 %) of OA at both sites, particularly in spring and summer. An ion fragment at m/z 75 is proposed as an additional marker for IEPOX-OA, as it is shown to correlate well with the m/z 82 ion shown to be associated with the aerosol mass spectrum of

  11. Characterization of a real-time tracer for isoprene epoxydiols-derived secondary organic aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

    DOE PAGES

    Hu, W. W.; Campuzano-Jost, P.; Palm, B. B.; Day, D. A.; Ortega, A. M.; Hayes, P. L.; Krechmer, J. E.; Chen, Q.; Kuwata, M.; Liu, Y. J.; et al

    2015-10-23

    to reflect large variations in its detailed molecular composition. The low fC5H6O (< 3 ‰) reported in non-IEPOX-derived isoprene-SOA from chamber studies indicates that this tracer ion is specifically enhanced from IEPOX-SOA, and is not a tracer for all SOA from isoprene. We introduce a graphical diagnostic to study the presence and aging of IEPOX-SOA as a triangle plot of fCO2 vs. fC5H6O. Finally, we develop a simplified method to estimate ambient IEPOX-SOA mass concentrations, which is shown to perform well compared to the full PMF method. The uncertainty of the tracer method is up to a factor of ~ 2, if the fC5H6O of the local IEPOX-SOA is not available. When only unit mass-resolution data are available, as with the aerosol chemical speciation monitor (ACSM), all methods may perform less well because of increased interferences from other ions at m/z 82. This study clarifies the strengths and limitations of the different AMS methods for detection of IEPOX-SOA and will enable improved characterization of this OA component.« less

  12. Comparison of stratospheric aerosol and gas experiment I (SAGE I) and Umkehr ozone profiles including a search for Umkehr aerosol effects

    SciTech Connect

    Newchurch, M.J.

    1986-01-01

    After briefly reviewing ozone depletion predictions from atmospheric models and results from trend analysis of Umkehr data, this paper outlines the Umkehr method for deducing the vertical profile of ozone and reviews the theoretical and empirical studies of the aerosol effect on Umkehr measurements. A brief description of the Stratospheric Aerosol and Gas Experiment I (SAGE I) is followed by a method for approximating the best representation of the conditions over the Umkehr ground site as seen by the SAGE I satellite. Using a spatially weighted average of SAGE I events derived from an autocorrelation analysis, the authors find 337 co-located SAGE I and Umkehr events. The approximate total column ozone measured by SAGE I is 5% higher than that measured by Umkehr on average. Most of this difference resides in Umkehr layer two, three, and four, while layers seven, eight, and nine contain small differences in average ozone content. Intercomparison with four other ozone studies indicates agreement between SAGE I and SBUV in most layers and at most Umkehr stations north of 30/sup 0/. However, significant differences in Umkehr layer eight between SAGE I and SBUV remain. Ozone differences between SAGE I and Umkehr are strong functions of both total column ozone and season in the lower layers but not in the upper layers.

  13. Development and characterization of a resistance spot welding aerosol generator and inhalation exposure system.

    PubMed

    Afshari, Aliakbar; Zeidler-Erdely, Patti C; McKinney, Walter; Chen, Bean T; Jackson, Mark; Schwegler-Berry, Diane; Friend, Sherri; Cumpston, Amy; Cumpston, Jared L; Leonard, H Donny; Meighan, Terence G; Frazer, David G; Antonini, James M

    2014-10-01

    Limited information exists regarding the health risks associated with inhaling aerosols that are generated during resistance spot welding of metals treated with adhesives. Toxicology studies evaluating spot welding aerosols are non-existent. A resistance spot welding aerosol generator and inhalation exposure system was developed. The system was designed by directing strips of sheet metal that were treated with an adhesive to two electrodes of a spot welder. Spot welds were made at a specified distance from each other by a computer-controlled welding gun in a fume collection chamber. Different target aerosol concentrations were maintained within the exposure chamber during a 4-h exposure period. In addition, the exposure system was run in two modes, spark and no spark, which resulted in different chemical profiles and particle size distributions. Complex aerosols were produced that contained both metal particulates and volatile organic compounds (VOCs). Size distribution of the particles was multi-modal. The majority of particles were chain-like agglomerates of ultrafine primary particles. The submicron mode of agglomerated particles accounted for the largest portion of particles in terms of particle number. Metal expulsion during spot welding caused the formation of larger, more spherical particles (spatter). These spatter particles appeared in the micron size mode and accounted for the greatest amount of particles in terms of mass. With this system, it is possible to examine potential mechanisms by which spot welding aerosols can affect health, as well as assess which component of the aerosol may be responsible for adverse health outcomes.

  14. Characterization of near-highway submicron aerosols in New York City with a high-resolution time-of-flight aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Sun, Y. L.; Zhang, Q.; Schwab, J. J.; Chen, W.-N.; Bae, M.-S.; Hung, H.-M.; Lin, Y.-C.; Ng, N. L.; Jayne, J.; Massoli, P.; Williams, L. R.; Demerjian, K. L.

    2011-11-01

    Knowledge of the variations of mass concentration, chemical composition and size distributions of submicron aerosols near roadways is of importance for reducing exposure assessment uncertainties in health effects studies. The goal of this study is to deploy and evaluate an Atmospheric Sciences Research Center-Mobile Laboratory (ASRC-ML), equipped with a suite of rapid response instruments for characterization of traffic plumes, adjacent to the Long Island Expressway (LIE) - a high-traffic highway in the New York City Metropolitan Area. In total, four measurement periods, two in the morning and two in the evening were conducted at a location approximately 30 m south of the LIE. The mass concentrations and size distributions of non-refractory submicron aerosol (NR-PM1) species were measured in situ at a time resolution of 1 min by an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer, along with rapid measurements (down to 1 Hz) of gaseous pollutants (e.g., HCHO, NO2, NO, O3, and CO2, etc.), black carbon (BC), and particle number concentrations and size distributions. The particulate organics varied dramatically during periods with highest traffic influences from the nearby roadway. The variations were mainly observed in the hydrocarbon-like organic aerosol (HOA), a surrogate for primary OA from vehicle emissions. The inorganic species (sulfate, ammonium, and nitrate) and oxygenated OA (OOA) showed much smoother variations - with minor impacts from traffic emissions. The concentration and chemical composition of NR-PM1 also varied differently on different days depending on meteorology, traffic intensity and vehicle types. Overall, organics dominated the traffic-related NR-PM1 composition (>60%) with HOA being the major fraction of OA. The traffic-influenced organics showed two distinct modes in mass-weighted size distributions, peaking at ~120 nm and 500 nm (vacuum aerodynamic diameter, Dva), respectively. OOA and inorganic species appear to be

  15. Urban aerosol in Oporto, Portugal: Chemical characterization of PM10 and PM2.5

    NASA Astrophysics Data System (ADS)

    Custódio, Danilo; Ferreira, Catarina; Alves, Célia; Duarte, Mácio; Nunes, Teresa; Cerqueira, Mário; Pio, Casimiro; Frosini, Daniele; Colombi, Cristina; Gianelle, Vorne; Karanasiou, Angeliki; Querol, Xavier

    2014-05-01

    Several urban and industrial areas in Southern Europe are not capable of meeting the implemented EU standards for particulate matter. Efficient air quality management is required in order to ensure that the legal limits are not exceeded and that the consequences of poor air quality are controlled and minimized. Many aspects of the direct and indirect effects of suspended particulate matter on climate and public health are not well understood. The temporal variation of the chemical composition is still demanded, since it enables to adopt off-set strategies and to better estimate the magnitude of anthropogenic forcing on climate. This study aims to provide detailed information on concentrations and chemical composition of aerosol from Oporto city, an urban center in Southern Europe. This city is located near the coast line in the North of Portugal, being the country's second largest urban area. Moreover, Oporto city economic prospects depend heavily on a diversified industrial park, which contribute to air quality degradation. Another strong source of air pollution is traffic. The main objectives of this study are: 1) to characterize the chemical composition of PM10 and PM2.5 by setting up an orchestra of aerosol sampling devices in a strategic place in Oporto; 2) to identify the sources of particles exploring parameters such as organic and inorganic markers (e.g. sugars as tracers for biomass burning; metals and elemental carbon for industrial and vehicular emissions); 3) to evaluate long range transport of pollutants using back trajectory analysis. Here we present data obtained between January 2013 and January 2014 in a heavy traffic roadside sampling site located in the city center. Different PM10 and PM2.5 samplers were operated simultaneously in order to collect enough mass on different filter matrixes and to fulfill the requirements of analytical methodologies. More than 100 aerosol samples were collected and then analysed for their mass concentration and

  16. Characterization of secondary organic aerosol generated from ozonolysis of α-pinene mixtures

    NASA Astrophysics Data System (ADS)

    Amin, Hardik S.; Hatfield, Meagan L.; Huff Hartz, Kara E.

    2013-03-01

    In the atmosphere, multiple volatile organic compounds (VOCs) co-exist, and they can be oxidized concurrently and generate secondary organic aerosol (SOA). In this work, SOA is formed by the oxidation (in presence of excess ozone) of mixtures containing α-pinene and other VOCs. The VOC mixtures were made so their composition approached a commercially-available α-pinene-based essential oil, Siberian fir needle oil. The SOA products were sampled using filters, solvent extracted and analyzed by gas chromatography/mass spectrometry with trimethylsilyl derivatization. The individual product yields for SOA generated from α-pinene changed upon the addition of other VOCs. An increase in concentration of non-reactive VOCs (bornyl acetate, camphene, and borneol) lead to a decrease in individual product yields of characteristic α-pinene SOA products. Although these experiments were carried out under higher VOC and ozone concentrations in comparison to the atmosphere, this work suggests that the role of non-reactive VOCs should be explored in SOA products formation.

  17. Particle Morphology and Size Results from the Smoke Aerosol Measurement Experiment-2

    NASA Technical Reports Server (NTRS)

    Urban, David L.; Ruff, Gary A.; Greenberg, Paul S.; Fischer, David; Meyer, Marit; Mulholland, George; Yuan, Zeng-Guang; Bryg, Victoria; Cleary, Thomas; Yang, Jiann

    2012-01-01

    Results are presented from the Reflight of the Smoke Aerosol Measurement Experiment (SAME-2) which was conducted during Expedition 24 (July-September 2010). The reflight experiment built upon the results of the original flight during Expedition 15 by adding diagnostic measurements and expanding the test matrix. Five different materials representative of those found in spacecraft (Teflon, Kapton, cotton, silicone rubber and Pyrell) were heated to temperatures below the ignition point with conditions controlled to provide repeatable sample surface temperatures and air flow. The air flow past the sample during the heating period ranged from quiescent to 8 cm/s. The smoke was initially collected in an aging chamber to simulate the transport time from the smoke source to the detector. This effective transport time was varied by holding the smoke in the aging chamber for times ranging from 11 to 1800 s. Smoke particle samples were collected on Transmission Electron Microscope (TEM) grids for post-flight analysis. The TEM grids were analyzed to observe the particle morphology and size parameters. The diagnostics included a prototype two-moment smoke detector and three different measures of moments of the particle size distribution. These moment diagnostics were used to determine the particle number concentration (zeroth moment), the diameter concentration (first moment), and the mass concentration (third moment). These statistics were combined to determine the diameter of average mass and the count mean diameter and, by assuming a log-normal distribution, the geometric mean diameter and the geometric standard deviations can also be calculated. Overall the majority of the average smoke particle sizes were found to be in the 200 nm to 400 nm range with the quiescent cases producing some cases with substantially larger particles.

  18. LASE measurements of water vapor and aerosol profiles during the Plains Elevated Convection at Night (PECAN) field experiment

    NASA Astrophysics Data System (ADS)

    Nehrir, A. R.; Ferrare, R. A.; Kooi, S. A.; Butler, C. F.; Notari, A.; Hair, J. W.; Collins, J. E., Jr.; Ismail, S.

    2015-12-01

    The Lidar Atmospheric Sensing Experiment (LASE) system was deployed on the NASA DC-8 aircraft during the Plains Elevated Convection At Night (PECAN) field experiment, which was conducted during June-July 2015 over the central and southern plains. LASE is an active remote sensor that employs the differential absorption lidar (DIAL) technique to measure range resolved profiles of water vapor and aerosols above and below the aircraft. The DC-8 conducted nine local science flights from June 30- July 14 where LASE sampled water vapor and aerosol fields in support of the PECAN primary science objectives relating to better understanding nocturnal Mesoscale Convective Systems (MCSs), Convective Initiation (CI), the Low Level Jet (LLJ), bores, and to compare different airborne and ground based measurements. LASE observed large spatial and temporal variability in water vapor and aerosol distributions in advance of nocturnal MCSs, across bores resulting from MCS outflow boundaries, and across the LLJ associated with the development of MCSs and CI. An overview of the LASE data collected during the PECAN field experiment will be presented where emphasis will be placed on variability of water vapor profiles in the vicinity of severe storms and intense convection in the central and southern plains. Preliminary comparisons show good agreement between coincident LASE and radiosonde water vapor profiles. In addition, an advanced water vapor DIAL system being developed at NASA Langley will be discussed.

  19. The Joint Aerosol-Monsoon Experiment (JAMEX): A Core Element for the Asian Monsoon Year (2008-2009)

    NASA Technical Reports Server (NTRS)

    Lau, WIlliam K. M.

    2007-01-01

    The objective of the Joint Aerosol-Monsoon Experiment (JAMEX) is to unravel the physical mechanisms and multi-scale interactions associated with aerosol-monsoon water cycle in the Asian Indo-Paczj?c region towards improved prediction of rainfall in land regions of the Asian monsoon. JAMEX will be planned as a five-year (2007-201 1) multi-national aerosol-monsoon research project, aimed at promoting collaboration, partnership and alignment of ongoing and planned national and international programs. Two coordinated special observing periods (SOP), covering the pre-monsoon (April-May) and the monsoon (June-August) periods is tentatively targeted for 2008 and 2009. The major work on validation and reference site coordination will take place in 2007 through the spring of 2008. A major science workshop is planned after SOP-I1 in 2010. Modeling and satellite data utilization studies will continue throughout the entire period to help in design of the observation arrays and measurement platforms for SOPS. The tentative time schedule, including milestones and research activities is shown in Fig. 1. One of the unique aspects of JAMEX is that it stems from grass-root scientific and societal imperatives, and it bridges a gap in existing national and international research programs. Currently we have identified 10 major national and international projects/programs separately for aerosols and monsoon research planned in the next five years in China, India, Japan, Italy, and the US, that could be potential contributors or partners with JAMEX. These include the Asian-Indo- Pacific Ocean (AIPO) Project and Aerosol Research Project from China, Monsoon Asian Hydro- Atmospheric Science Research and predication Initiative (MAHASRI) from Japan, Continental Tropical Convergence Zone (CTCZ) and Severe Thunderstorm: Observations and Regional Modeling (STORM) from India, Share-Asia from Italy, Atmospheric Brown Cloud (ABC), Pacific Aerosol-Cloud-Dust Experiment (PACDEX), East Asia Study of

  20. The Joint Aerosol-Monsoon Experiment (JAMEX): A Core Element for the Asian Monsoon Year (2008-2009)

    NASA Technical Reports Server (NTRS)

    Lau, William K.M.

    2007-01-01

    The objective of the Joint Aerosol-Monsoon Experiment (JAMEX) is to unravel the physical mechanisms and multi-scale interactions associated with aerosol-monsoon water cycle in the Asian Indo-Pacific region towards improved prediction of rainfall in land regions of the Asian monsoon. JAMEX will be planned as a five-year (2007-201 1) multi-national aerosol-monsoon research project, aimed at promoting collaboration, partnership and alignment of ongoing and planned national and international programs. Two coordinated special observing periods (SOP), covering the pre-monsoon (April-May) and the monsoon (June-August) periods is tentatively targeted for 2008 and 2009. The major work on validation and reference site coordination will take place in 2007 through the spring of 2008. A major science workshop is planned after SOP-I1 in 2010. Modeling and satellite data utilization studies will continue throughout the entire period to help in design of the observation arrays and measurement platforms for SOPS. The tentative time schedule, including milestones and research activities is shown in Fig. 1. One of the unique aspects of JAMEX is that it stems from grass-root scientific and societal imperatives, and it bridges a gap in existing national and international research programs. Currently we have identified 10 major national and international projects/programs separately for aerosols and monsoon research planned in the next five years in China, India, Japan, Italy, and the US, that could be potential contributors or partners with JAMEX. These include the Asian-Indo- Pacific Ocean (AIPO) Project and Aerosol Research Project from China, Monsoon Asian Hydro- Atmospheric Science Research and predication Initiative (MAHASRI) from Japan, Continental Tropical Convergence Zone (CTCZ) and Severe Thunderstorm: Observations and Regional Modeling (STORM) from India, Share-Asia from Italy, Atmospheric Brown Cloud (ABC), Pacific Aerosol-Cloud-Dust Experiment (PACDEX), East Asia Study of

  1. Atmospheric aerosol characterization during Saharan dust outbreaks at Naples EARLINET station

    NASA Astrophysics Data System (ADS)

    Pisani, Gianluca; Armenante, Mario; Boselli, Antonella; Frontoso, Maria Grazia; Spinelli, Nicola; Wang, Xuan

    2007-10-01

    The optical properties and the spatial distribution of the tropospheric aerosols over Naples under Saharan dust outbreaks conditions have been studied by means of lidar measurements performed between May 2000 and August 2003 in the frame of the EARLINET project. Climatological analysis of sand plume has been done by comparing normal and dust affected conditions. Results in terms of backscattering and extinction coefficient as well as their integrated quantities show that the aerosol load from the ground level up to 2 Km during Saharan dust transport events is almost the same of normal conditions. This is probably due to the relevant widespread of local aerosol sources, such as vehicular traffic, industrial activities, etc. Nevertheless, when sand outbreaks occur, the extinction to backscattering ratio, i.e. the lidar ratio, clearly shows that the aerosol type in the lowest atmospheric layer changes. Moreover, Saharan dust transport events strong increase both integrated backscatter and optical dept above 2 km.

  2. The ambient organic aerosol soluble in water: Measurements, chemical characterization, and an investigation of sources

    NASA Astrophysics Data System (ADS)

    Sullivan, Amy P.

    This thesis characterizes the ambient fine organic carbon (OC) aerosol and investigates its sources through the development and deployment of new analytical measurement techniques. Recognizing that OC is highly chemically complex, the approach was to develop methods capable of quantitatively measuring a large chemical fraction of the aerosol instead of specific chemical speciation. The focus is on organic compounds that are soluble in water (WSOC) since little is known about its chemical nature. The results from this thesis show that WSOC has mainly two sources: biomass burning and secondary organic aerosol (SOA). In urban areas, WSOC increases with plume age, and tracks other photochemically produced compounds. Chemical analysis of WSOC suggests that in urban Atlanta, the SOA is mainly small-chain aliphatic compounds indirectly linked to vehicle emissions. A method was first developed for quantitative on-line measurements of WSOC by extending the application of the Particle-into-Liquid Sampler (PILS) from inorganic to organic aerosol measurements. In this approach a PILS captures ambient particles into a flow of purified water, which is then forced through a liquid filter and the carbonaceous content quantified on-line by a Total Organic Carbon (TOC) analyzer. An instrument was first developed for ground-based measurements and then modified for airborne deployment. Ground-based measurements at the St. Louis - Midwest Supersite during the summer of 2003 showed that the fraction of OC that is water-soluble can have a highly diurnal pattern with WSOC to OC ratios reaching 0.80 during the day and lows of 0.40 during the night. During extended periods under stagnation pollution events, this pattern was well correlated with ozone concentrations. The results are consistent with formation of SOA. Airborne PILS-TOC measurements from the NOAA WP-3D during the New England Air Quality Study/Intercontinental Transport and Chemical Transformation (NEAQS/ITCT) 2004 program

  3. Characterization of aerosols over oceanic regions around India during pre-monsoon 2006

    NASA Astrophysics Data System (ADS)

    Kalapureddy, M. C. R.; Devara, P. C. S.

    Ship cruise observations of aerosol optical properties have been carried out over oceanic areas around India during pre-monsoon season of 2006. The results reveal rather significant day-to-day variability in aerosol optical thickness (AOT). Aerosol loading is found to be relatively high over the Bay of Bengal (BoB) i.e., AOT at 500 nm is 0.36 ± 0.12 which is higher than those over Arabian Sea (AS) i.e., 0.23 ± 0.09 and North Indian Ocean (NIO) i.e., 0.26 ± 0.10. Dominance of fine-mode ( α = 1.21 ± 0.11) and coarse-mode ( α = 0.86 ± 0.20) aerosol particles has been observed, respectively, over the BoB and AS regions. Second order Angstrom exponent shows predominant positive and negative curvatures over BoB and AS, respectively. High fine-mode aerosol loading over BoB is found to be associated with air masses originating from northeastern Indo-Gangetic plains and southeastern Myanmar. The observed short wave solar flux decrease due to aerosol extinction is found to be 24, 19 and 21 W m -2 for the BoB, AS and NIO, respectively.

  4. Characterization of a Quadrotor Unmanned Aircraft System for Aerosol-Particle-Concentration Measurements.

    PubMed

    Brady, James M; Stokes, M Dale; Bonnardel, Jim; Bertram, Timothy H

    2016-02-01

    High-spatial-resolution, near-surface vertical profiling of atmospheric chemical composition is currently limited by the availability of experimental platforms that can sample in constrained environments. As a result, measurements of near-surface gradients in trace gas and aerosol particle concentrations have been limited to studies conducted from fixed location towers or tethered balloons. Here, we explore the utility of a quadrotor unmanned aircraft system (UAS) as a sampling platform to measure vertical and horizontal concentration gradients of trace gases and aerosol particles at high spatial resolution (1 m) within the mixed layer (0-100 m). A 3D Robotics Iris+ autonomous quadrotor UAS was outfitted with a sensor package consisting of a two-channel aerosol optical particle counter and a CO2 sensor. The UAS demonstrated high precision in both vertical (±0.5 m) and horizontal positions (±1 m), highlighting the potential utility of quadrotor UAS drones for aerosol- and trace-gas measurements within complex terrain, such as the urban environment, forest canopies, and above difficult-to-access areas such as breaking surf. Vertical profiles of aerosol particle number concentrations, acquired from flights conducted along the California coastline, were used to constrain sea-spray aerosol-emission rates from coastal wave breaking. PMID:26730457

  5. Characterization of a Quadrotor Unmanned Aircraft System for Aerosol-Particle-Concentration Measurements.

    PubMed

    Brady, James M; Stokes, M Dale; Bonnardel, Jim; Bertram, Timothy H

    2016-02-01

    High-spatial-resolution, near-surface vertical profiling of atmospheric chemical composition is currently limited by the availability of experimental platforms that can sample in constrained environments. As a result, measurements of near-surface gradients in trace gas and aerosol particle concentrations have been limited to studies conducted from fixed location towers or tethered balloons. Here, we explore the utility of a quadrotor unmanned aircraft system (UAS) as a sampling platform to measure vertical and horizontal concentration gradients of trace gases and aerosol particles at high spatial resolution (1 m) within the mixed layer (0-100 m). A 3D Robotics Iris+ autonomous quadrotor UAS was outfitted with a sensor package consisting of a two-channel aerosol optical particle counter and a CO2 sensor. The UAS demonstrated high precision in both vertical (±0.5 m) and horizontal positions (±1 m), highlighting the potential utility of quadrotor UAS drones for aerosol- and trace-gas measurements within complex terrain, such as the urban environment, forest canopies, and above difficult-to-access areas such as breaking surf. Vertical profiles of aerosol particle number concentrations, acquired from flights conducted along the California coastline, were used to constrain sea-spray aerosol-emission rates from coastal wave breaking.

  6. Intercomparison of stratospheric water vapor observed by satellite experiments - Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    A comparison is made of the stratospheric water vapor measurements made by the satellite sensors of the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus-7 LIMS, and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. It was found that, despite differences in the measurement techniques, sampling bias, and observational periods, the three experiments have disclosed a generally consistent pattern of stratospheric water vapor distribution. The only significant difference occurs at high southern altitudes in May below 18 km, where LIMS measurements were 2-3 ppmv greater than those of SAGE II and ATMOS.

  7. Southern Great Plains Ice Nuclei Characterization Experiment Final Campaign Summary

    SciTech Connect

    DeMott, PJ; Suski, KJ; Hill, TCJ; Levin, EJT

    2015-03-01

    The first ever ice nucleating particle (INP) measurements to be collected at the Southern Great Plains site were made during a period from late April to June 2014, as a trial for possible longer-term measurements at the site. These measurements will also be used to lay the foundation for understanding and parameterizing (for cloud resolving modeling) the sources of these climatically important aerosols as well as to augment the existing database containing this knowledge. Siting the measurements during the spring was intended to capture INP sources in or to this region from plant, soil, dust transported over long distances, biomass burning, and pollution aerosols at a time when they may influence warm-season convective clouds and precipitation. Data have been archived of real-time measurements of INP number concentrations as a function of processing conditions (temperature and relative humidity) during 18 days of sampling that spanned two distinctly different weather situations: a warm, dry and windy period with regional dust and biomass burning influences in early May, and a cooler period of frequent precipitation during early June. Precipitation delayed winter wheat harvesting, preventing intended sampling during that perturbation on atmospheric aerosols. INP concentrations were highest and most variable at all temperatures in the dry period, where we attribute the INP activity primarily to soil dust emissions. Additional offline INP analyses are underway to extend the characterization of INP to cover the entire mixed phase cloud regime from -5°C to -35°C during the full study. Initial comparisons between methods on four days show good agreement and excellent future promise. The additional offline immersion freezing data will be archived as soon as completed under separate funding. Analyses of additional specialized studies for specific attribution of INP to biological and smoke sources are continuing via the National Science Foundation and National Aeronautics

  8. Characterization of Atmospheric Aerosol Particles from a Mining City in Southwest China Using Electron Probe microanalysis

    NASA Astrophysics Data System (ADS)

    Cheng, X.; Huang, Y.; Lu, H., III; Liu, Z., IV; Wang, N. V.

    2015-12-01

    Xin Cheng1, Yi Huang1*, Huilin Lu2, Zaidong Liu2, Ningming Wang21 Key Laboratory of Geological Nuclear Technology of Sichuan Province, College of Earth Science, Chengdu University of Technology, Chengdu 610059, China. ; E-mail:chengxin_cdut@163.com 2 College of Earth Science, Chengdu University of Technology, Chengdu 610059, China. ; *Corresponding author: E-mail: huangyi@cdut.cn Panzhihua is a mining city located at Pan-Xi Rift valley, southwest China. It has a long industrial history of vanadium-titanium magnetite mining, iron and steel smelting, and coal-fired power plants. Atomospheric environment has been seriously contaminated with airborne paticles, which is threatening human health.The harmful effects of aerosols are dependent on certain characteristics such as microphysical properties. However, few studsies have been carried out on morphological information contained on single atmospheric particles in this area. In this study, we provide a detailed morphologically and chemically characterization of airborne particles collected at Panzhihua city in October, 2014, using a quantitative single particle analysis based on EPXMA. The results indicate that based on their chemical composition, five major types of particles were identified. Among these, aluminosilicate particles have typical spherical shapes and are produced during the high-temperature combustion; Fe-containing particles contains high level of Mn, and more likely originated from mineralogical and steel industry; Si-containing particles can originate from mineralogical source; V-Ti-Mn-containing particles are also produced by steel industry; Ca-containing particles,these particles are CaCO3, mainly from the mining of limestone mine. The results help us on tracing and partitioning different sources of atomospheric particles in the industrial area. Fig.1 Fe-rich shperical particles

  9. A comparison of the Stratospheric Aerosol and Gas Experiment II tropospheric water vapor to radiosonde measurements

    SciTech Connect

    Larsen, J.C.; Chiou, E.W. ); Chu, W.P.; McCormick, M.P.; McMaster, L.R. ); Oltmans, S. ); Rind, D. )

    1993-03-20

    Upper tropospheric Stratospheric Aerosol and Gas Experiment II (SAGE II) water vapor observations are compared to correlative radiosonde observations and radiosonde based climatologies. The SAGE II 1987 monthly zonal mean water vapor climatology is compared to both the Global Atmospheric Circulation Statistics (1963-1973) climatology and to the 1987 radiosonde climatology. The clear sky SAGE II climatology is found to be approximately half the level of both the clear/cloudy sky radiosonde climatologies. To determine whether this is realistic for these two different climatologies or includes additional observational and instrumental biases, the authors took the 1987 radiosonde data set and identified approximately 800 correlative profile pairs. The observational biases inherent to SAGE II and the radiosondes produce a set of profile pairs characteristic of clear sky, land conditions. A critical review of the radiosonde measurement capability was carried out to establish the operating range and accuracy in the upper troposphere. The authors show that even with tight coincidence criterion, the quality of the profile pair comparisons varies considerably because of strong water vapor variability occurring on small time and space scales. Annual zonal means calculated from the set of profile pairs again finds SAGE II significantly drier in many latitude bands. Resolving the radiosonde data base by hygrometer type shows this to be true for all hygrometers except for the thin film capacitive type (Vaisala Humicap). For this hygrometer, between 4.5 and 6.5 km SAGE II is drier by approximately 25.%, and from 8.5 to 11.5 km they are nearly equivalent when global annual means are compared. The good agreement with the Vaisala Humicap, currently the most accurate and responsive hygrometer in operational use, suggests existing radiosonde climatologies contain a significant moist bias in the upper troposphere. 31 refs., 16 figs., 6 tabs.

  10. Thermally sensitive block copolymer particles prepared via aerosol flow reactor method: Morphological characterization and behavior in water

    PubMed Central

    Nykänen, Antti; Rahikkala, Antti; Hirvonen, Sami-Pekka; Aseyev, Vladimir; Tenhu, Heikki; Mezzenga, Raffaele; Raula, Janne; Kauppinen, Esko; Ruokolainen, Janne

    2012-01-01

    This work describes properties of thermo-sensitive submicron sized particles having the same chemical composition but different morphologies. These particles have been prepared with an aerosol technique using dimethylformamide solutions of linear polystyrene-block-poly(N-isopropylacrylamide-block-polystyrene, PS-b-PNIPAM-b-PS. The particles were characterized by cryo-electron microscopy, microcalorimetry, and light scattering. Block-copolymers self-assembled within the particles forming onion-like, gyroid-like, and spherical morphologies having poly(N-isopropylacrylamide) matrix and physically cross-linking polystyrene domains. The particles were dispersed in aqueous media and their behavior in water was studied both below and above the lower critical solution temperature of poly(N-isopropylacrylamide). We found out that the particles with spherical and gyroid-like morphologies swell considerably in water at 20 °C, whereas at 40 °C the particles resemble more of those studied without water treatment. Light scattering experiments showed that the particles gradually aggregate and precipitate with time at 40 °C. Microcalorimetric studies revealed for all three studied morphologies that PNIPAM undergoes a two-step transition due to the different hydration levels of PNIPAM inside and outside the particles. Thicknesses of the PS and PNIPAM layers within the onion-like particles were analyzed using the TEM micrographs by fitting a model of electron density to the integrated electron intensity data. The surface layer of the particles was found out to be PNIPAM, which was supported by light scattering and microcalorimetry. It was also found out from the TEM micrograph analysis that the width of the outmost PS layer is considerably thinner than the one in the dry state prior to immersion in water, and a degradation scheme is proposed to explain these results. PMID:23150721

  11. Organic Composition of Size-Segregated Aerosols Sampled During the 2002 Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA

    NASA Astrophysics Data System (ADS)

    Tremblay, R. T.; Zika, R. G.

    2003-04-01

    Aerosol samples were collected for the analysis of organic source markers using non-rotating Micro Orifice Uniform Deposit Impactors (MOUDI) as part of the Bay Regional Atmospheric Chemistry Experiment (BRACE) in Tampa, FL, USA. Daily samples were collected 12 m above ground at a flow rate of 30 lpm throughout the month of May 2002. Aluminum foil discs were used to sample aerosol size fractions with aerodynamic cut diameter of 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.17 and 0.093 um. Samples were solvent extracted using a mixture of dichloromethane/acetone/hexane, concentrated and then analyzed using gas chromatography-mass spectrometry (GC/MS). Low detection limits were achieved using a HP Programmable Temperature Vaporizing inlet (PTV) and large volume injections (80ul). Excellent chromatographic resolution was obtained using a 60 m long RTX-5MS, 0.25 mm I.D. column. A quantification method was built for over 90 organic compounds chosen as source markers including straight/iso/anteiso alkanes and polycyclic aromatic hydrocarbons (PAH). The investigation of potential aerosol sources for different particle sizes using known organic markers and source profiles will be presented. Size distributions of carbon preference indices (CPI), percent wax n-alkanes (%WNA) and concentration of selected compounds will be discussed. Also, results will be compared with samples acquired in different environments including the 1999 Atlanta SuperSite Experiment, GA, USA.

  12. 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

  13. Discrimination of water, ice and aerosols by light polarisation in the CLOUD experiment

    NASA Astrophysics Data System (ADS)

    Nichman, L.; Fuchs, C.; Järvinen, E.; Ignatius, K.; Höppel, N. F.; Dias, A.; Heinritzi, M.; Simon, M.; Tröstl, J.; Wagner, A. C.; Wagner, R.; Williamson, C.; Yan, C.; Bianchi, F.; Connolly, P. J.; Dorsey, J. R.; Duplissy, J.; Ehrhart, S.; Frege, C.; Gordon, H.; Hoyle, C. R.; Kristensen, T. B.; Steiner, G.; Donahue, N. M.; Flagan, R.; Gallagher, M. W.; Kirkby, J.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Stratmann, F.; Tomé, A.

    2015-11-01

    Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather and General Circulation Models (GCMs). The simultaneous detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud-particle size range below 50 μm, remains challenging in mixed phase, often unstable ice-water phase environments. The Cloud Aerosol Spectrometer with Polarisation (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure their effects on the backscatter polarisation state. Here we operate the versatile Cosmics-Leaving-OUtdoor-Droplets (CLOUD) chamber facility at the European Organisation for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water and ice particles. In this paper, optical property measurements of mixed phase clouds and viscous Secondary Organic Aerosol (SOA) are presented. We report observations of significant liquid - viscous SOA particle polarisation transitions under dry conditions using CASPOL. Cluster analysis techniques were subsequently used to classify different types of particles according to their polarisation ratios during phase transition. A classification map is presented for water droplets, organic aerosol (e.g., SOA and oxalic acid), crystalline substances such as ammonium sulphate, and volcanic ash. Finally, we discuss the benefits and limitations of this classification approach for atmospherically relevant concentration and mixtures with respect to the CLOUD 8-9 campaigns and its potential contribution to Tropical Troposphere Layer (TTL) analysis.

  14. A study on the extent of neutralization of sulphate aerosol through laboratory and field experiments using an ATOFMS and a GPIC

    NASA Astrophysics Data System (ADS)

    Yao, Xiaohong; Rehbein, Peter J. G.; Lee, Colin J.; Evans, Greg J.; Corbin, Joel; Jeong, Cheol-Heon

    2011-11-01

    Extent of neutralization (EoN) of atmospheric aerosol is an important parameter in understanding related nucleation mechanisms, acid-catalyzed reactions and gas-aerosol partitioning. Ion m/ z -195 (HSOHSO4-) detected by the Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) has been used as an indicator of incompletely-neutralized sulphate aerosol, but there are no laboratory data to support this assumption. In this study, experiments using artificially generated sulphuric acid nucleated aerosol and metal sulphate aerosol across a range of EoN found that the peak area ratio and hit ratio of ion m/ z -195 (HSOHSO4-) to ion m/ z -97 (HSO4-) detected by the ATOFMS increased with decreasing EoN. Area ratio and hit ratio are sensitive to EoN at the low and high value zones, respectively. In ambient air measured by the ATOFMS and a Gas Particle Ion Chromatograph (GPIC) in Toronto, Canada, ion m/ z -195 was always detected in ammonium sulphate aerosol, and its hit number and peak area varied widely, regardless of EoN indicated by the equivalent ratio of NH4+ to (SO42-+NO3-). Thus, ion m/ z -195 alone is not an indicator of acidic sulphate aerosol. The combined approach using the ATOFMS and the GPIC found that cloud-processing formed incompletely-neutralized acidic sulphate aerosol in 2 out of 35 days sampled in winter in Toronto, Canada. It is interesting that the two episodes both occurred at night. Formation of incompletely-neutralized acidic sulphate aerosol caused a decrease in the concentration of particulate nitrate. This can be explained by acidic sulphate aerosol reacting with ammonium nitrate, leading to the release of HNO 3 to the gas phase. It was also found that the GPIC results occasionally suffered a positive artifact of NH4+ concentration caused by the clogging-induced high back-pressure in the instrument.

  15. Long- and/or short-range transportation of local Asian aerosols in DRAGON-Osaka Experiment

    NASA Astrophysics Data System (ADS)

    Nakata, M.; Sano, I.; Mukai, S.; Holben, B. N.

    2013-12-01

    This work intends to demonstrate the spatial and temporal variation of atmospheric particles in East Asia, especially around AERONET (Aerosol Robotics Network) -Osaka site during Dragon Asia period in the spring of 2012, named Dragon-Osaka. It is known that the air pollution in East Asia becomes to be severe due to both the increasing emissions of the anthropogenic aerosols associated with economic growth and the complicated behavior of natural aerosols. Thus the precise observations of atmospheric particles in East Asia are desired. Osaka is the second big city in Japan and a typical Asian urban area. The population of the region is around 20 millions including neighbor prefectures. Therefore, air quality in the region is slightly bad compared to remote area due to industries and auto mobiles. In recent years, Asian dusts and anthropogenic small particles transported from China and cover those cities throughout year. AERONET Osaka site was established in 2002 on the campus of Kinki University. Nowadays, LIDAR (Light Detection and Ranging), an SPM sampler (SPM-613D, Kimoto Electric, Japan) and others are available on the roof of a building. The site data are useful for algorithm development of aerosol retrieval over busy city. On the other hand, human activities in this region also emit the huge amount of pollutions, thus it is needed to investigate the local distribution of aerosols in this region. In order to investigate change of aerosol properties, PM-individual analysis is made with scanning electron microscope (SEM) coupled with energy dispersive X-ray analyzer (EDX). SEM/EDX is an effective instrument to observe the surface microstructure and analyze the chemical composition of such materials as metals, powders, biological specimens, etc. We used sampling data from the SPM sampler at AERONET Osaka site. During a period of DRAGON-Asia, high concentrations of air pollutant were observed on the morning of March 11 in Fukue Island in the East China Sea. On the

  16. Mass spectrometric characterization of isomeric terpenoic acids from the oxidation of α-pinene, β-pinene, d-limonene, and Δ3-carene in fine forest aerosol.

    PubMed

    Yasmeen, Farhat; Szmigielski, Rafal; Vermeylen, Reinhilde; Gómez-González, Yadian; Surratt, Jason D; Chan, Arthur W H; Seinfeld, John H; Maenhaut, Willy; Claeys, Magda

    2011-04-01

    In this study, we present liquid chromatographic and mass spectral data for predominant terpenoic acids formed through oxidation of α-pinene, β-pinene, d-limonene, and Δ(3)-carene that occur in fine forest aerosol from K-puszta, Hungary, a rural site with coniferous vegetation. Characterization of these secondary organic aerosol tracers in fine ambient aerosol is important because it allows one to gain information on monoterpene precursors and source processes such as oxidation and aging processes. The mass spectral data were obtained using electrospray ionization in the negative ion mode, accurate mass measurements, and linear ion trap tandem mass spectrometric experiments. Emphasis is given to the mass spectrometric differentiation of isobaric terpenoic acids, such as, e.g. the molecular weight (MW) 186 terpenoic acids, cis-pinic, cis-caric, homoterpenylic, ketolimononic, and limonic acids. Other targeted isobaric terpenoic acids are the MW 184 terpenoic acids, cis-pinonic and cis-caronic acids, and the MW 204 tricarboxylic acids, 3-methyl-1,2,3-butanetricarboxylic and 3-carboxyheptanedioic acids. Fragmentation pathways are proposed to provide a rational explanation for the observed isomeric differences and/or to support the suggested tentative structures. For the completeness of the data set, data obtained for recently reported lactone-containing terpenoic acids (i.e. terpenylic and terebic acids), related or isobaric compounds (i.e. norpinic acid, diaterpenylic acid acetate, and unknown MW 188 compounds) are also included, the rationale being that other groups working on this topic could use this data compilation as a reference.

  17. Generation and characterization of sodium sulfite aerosols for applications in inhalation toxicologic research

    SciTech Connect

    Dasgupta, P.K.; Raabe, O.G.; Duvall, T.R.; Tarkington, B.K.

    1980-09-01

    A method was developed for generation of submicrometer aerosols of sodium sulfite suitable for use in inhalation toxicologic research. Concentrations ranging up to about 30 mg/m/sup 3/Na/sub 2/SO/sub 3/ were achieved in a 0.44 m/sup 3/ exposure chamber with an air flow rate of 0.20 m/sup 3//min for periods up to 16 days. The coefficient of variation of the sulfite aerosol mass concentration was about 4% during a typical exposure period. The measured mass median aerodynamic diameters (MMAD/sub ar/) of the generated aerosols were 1.2 (+-0.2SD) ..mu..m with a geometric standard deviation (sigma g) of 1.9 (+-0.3SD). The chamber was sampled for gas phase SO/sub 2/ concentration, and aerosol samples were analyzed for particulate sulfite and sulfate. The fraction of sulfur as sulfite in the aerosol was usually 95% and was always greater than 90%. Gas phase SO/sub 2/ amounted to less than 2% of the total S(IV) present in the chamber.

  18. Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

    NASA Astrophysics Data System (ADS)

    Weschler, Charles J.; Shields, Helen C.

    Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution of their particle size distributions. The experiments were performed in a manipulated office setting containing a constant source of d-limonene and an ozone generator that was remotely turned "on" or "off" at 6 h intervals. The particle number concentrations were monitored using an optical particle counter with eight-channels ranging from 0.1-0.2 to>2.0 μm diameter. The air exchange rates during the experiments were either high (working hours) or low (non-working hours) and ranged from 1.6 to>12 h -1, with intermediate exchange rates. Given the emission rates of ozone and d-limonene used in these studies, at an air exchange rate of 1.6 h -1 particle number concentration in the 0.1-0.2 μm size-range peaked 1.2 h after the ozone generator was switched on. In the ensuing 4.8 h particle counts increased in successive size-ranges up to the 0.5-0.7 μm diameter range. At higher air exchange rates, the resulting concentrations of total particles and particle mass (calculated from particle counts) were smaller, and at exchange rates exceeding 12 h -1, no excess particle formation was detectable with the instrument used in this study. Particle size evolved through accretion and, in some cases, coagulation. There was evidence for coagulation among particles in the smallest size-range at low air exchange rates (high particle concentrations) but no evidence of coagulation was apparent at higher air exchange rates (lower particle concentrations). At higher air exchange rates the particle count or size distributions were shifted towards smaller particle diameters and less time was required to achieve the maximum concentration in each of the size-ranges where discernable particle growth

  19. Smog chamber experiments to investigate Henry's law constants of glyoxal using different seed aerosols

    NASA Astrophysics Data System (ADS)

    Jakob, Ronit

    2014-05-01

    Aerosols play an important role in the chemistry and physics of the atmosphere. Hence, they have a direct as well as an indirect impact on the earth's climate. Depending on their formation, one distinguishes between primary and secondary aerosols[1]. Important groups within the secondary aerosols are the secondary organic aerosols (SOAs). In order to improve predictions about these impacts on the earth's climate the existing models need to be optimized, because they still underestimate SOA formation[2]. Glyoxal, the smallest α-dicarbonyl, not only acts as a tracer for SOA formation but also as a direct contributor to SOA. Because glyoxal has such a high vapour pressure, it was common knowledge that it does not take part in gas-particle partitioning and therefore has no impact on direct SOA formation. However, the Henry's law constant for glyoxal is surprisingly high. This has been explained by the hydration of the aldehyde groups, which means that a species with a lower vapour pressure is produced. Therefore the distribution of glyoxal between gas- and particle phase is atmospherically relevant and the direct contribution of glyoxal to SOA can no longer be neglected. A high salt concentration present in chamber seed aerosols leads to an enhanced glyoxal uptake into the particle. This effect is called "salting-in". The salting effect depends on the composition of the seed aerosol as well as the soluble compound. For very polar compounds, like glyoxal, a "salting-in" is observed[3]. Glyoxal particle formation during a smog chamber campaign at Paul-Scherrer-Institut (PSI) in Switzerland was examined using different seed aerosols such as ammonium sulfate, sodium chloride and sodium nitrate. The aim of this campaign was to investigate Henry's law constants for different seed aerosols. During the campaign filter samples were taken to investigate the amount of glyoxal in the particle phase. After filter extraction, the analyte was derivatized and measured using UHPLC

  20. Generation of Mie size microdroplet aerosols with applications in laser-driven fusion experiments.

    PubMed

    Higginbotham, A P; Semonin, O; Bruce, S; Chan, C; Maindi, M; Donnelly, T D; Maurer, M; Bang, W; Churina, I; Osterholz, J; Kim, I; Bernstein, A C; Ditmire, T

    2009-06-01

    We have developed a tunable source of Mie scale microdroplet aerosols that can be used for the generation of energetic ions. To demonstrate this potential, a terawatt Ti:Al2O3 laser focused to 2 x 10(19) W/cm2 was used to irradiate heavy water (D2O) aerosols composed of micron-scale droplets. Energetic deuterium ions, which were generated in the laser-droplet interaction, produced deuterium-deuterium fusion with approximately 2 x 10(3) fusion neutrons measured per joule of incident laser energy. PMID:19566203

  1. Climatology of Aerosol Optical Properties in Southern Africa

    NASA Technical Reports Server (NTRS)

    Queface, Antonio J.; Piketh, Stuart J.; Eck, Thomas F.; Tsay, Si-Chee

    2011-01-01

    A thorough regionally dependent understanding of optical properties of aerosols and their spatial and temporal distribution is required before we can accurately evaluate aerosol effects in the climate system. Long term measurements of aerosol optical depth, Angstrom exponent and retrieved single scattering albedo and size distribution, were analyzed and compiled into an aerosol optical properties climatology for southern Africa. Monitoring of aerosol parameters have been made by the AERONET program since the middle of the last decade in southern Africa. This valuable information provided an opportunity for understanding how aerosols of different types influence the regional radiation budget. Two long term sites, Mongu in Zambia and Skukuza in South Africa formed the core sources of data in this study. Results show that seasonal variation of aerosol optical thicknesses at 500 nm in southern Africa are characterized by low seasonal multi-month mean values (0.11 to 0.17) from December to May, medium values (0.20 to 0.27) between June and August, and high to very high values (0.30 to 0.46) during September to November. The spatial distribution of aerosol loadings shows that the north has high magnitudes than the south in the biomass burning season and the opposite in none biomass burning season. From the present aerosol data, no long term discernable trends are observable in aerosol concentrations in this region. This study also reveals that biomass burning aerosols contribute the bulk of the aerosol loading in August-October. Therefore if biomass burning could be controlled, southern Africa will experience a significant reduction in total atmospheric aerosol loading. In addition to that, aerosol volume size distribution is characterized by low concentrations in the non biomass burning period and well balanced particle size contributions of both coarse and fine modes. In contrast high concentrations are characteristic of biomass burning period, combined with

  2. Characterization of oxygenated derivatives of isoprene related to 2-methyltetrols in Amazonian aerosols using trimethylsilylation and gas chromatography/ion trap mass spectrometry.

    PubMed

    Wang, Wu; Kourtchev, Ivan; Graham, Bim; Cafmeyer, Jan; Maenhaut, Willy; Claeys, Magda

    2005-01-01

    In the present study, we have tentatively identified the structures of three oxygenated derivatives of isoprene in Amazonian rain forest aerosols as the C(5) alkene triols, 2-methyl-1,3,4-trihydroxy-1-butene (cis and trans) and 3-methyl-2,3,4-trihydroxy-1-butene. The formation of these oxygenated derivatives of isoprene can be explained by acid-catalyzed ring opening of epoxydiol derivatives of isoprene, namely, 1,2-epoxy-2-methyl-3,4-dihydroxybutane and 1,2-dihydroxy-2-methyl-3,4-epoxybutane. The structural proposals of the C(5) alkene triols were based on chemical derivatization reactions and detailed interpretation of electron and chemical ionization mass spectral data, including data obtained from first-order mass spectra, deuterium labeling of the trimethylsilyl methyl groups, and MS(2) ion trap experiments. The characterization of 2-methyl-1,3,4-trihydroxy-1-butene (cis and trans) and 3-methyl-2,3,4-trihydroxy-1-butene in forest aerosols is important from an atmospheric chemistry viewpoint in that these compounds hint at the formation of intermediate isomeric epoxydiol derivatives of isoprene and as such provide mechanistic insights into the formation of the previously reported 2-methyltetrols through photooxidation of isoprene.

  3. Functional characterization of the water-soluble organic carbon of size fractionated aerosol in the Southern Mississippi Valley

    NASA Astrophysics Data System (ADS)

    Chalbot, M.-C. G.; Brown, J.; Chitranshi, P.; Gamboa da Costa, G.; Pollock, E. D.; Kavouras, I. G.

    2014-02-01

    The chemical content of the water soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to: (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for the period when carbonaceous aerosol was the most abundant particulate component. The WSOC accounted for 5% of particle mass for particles with dp > 0.96 μm and 10% of particle mass for particles with dp < 0.96 μm. Non-exchangeable aliphatic (H-C), unsaturated aliphatic (H-C-C=), oxygenated saturated aliphatic (H-C-O), acetalic (O-CH-O) and aromatic (Ar-H) protons were determined by proton nuclear magnetic resonance. The total non-exchangeable organic hydrogen concentrations varied from 4.1 ± 0.1 nmol m-3 for particles with 0.96 < dp < 1.5 μm to 73.9 ± 12.3 nmol m-3 for particles with dp < 0.49 μm, resulting in molar H / C ratios of 0.48 ± 0.05 to 0.92 ± 0.09 observed in combustion-related organic aerosol. The R-H was the most abundant group representing about 45% of measured total non-exchangeable organic hydrogen concentration followed by H-C-O (27%) and H-C-C= (26%). Levoglucosan, amines, ammonium and methanosulfonate were tentatively identified in NMR fingerprints of fine particles. Sucrose, fructose, glucose, formate and acetate were associated with coarse particles. These qualitative differences of 1H-NMR profiles for different particle sizes indicated the possible contribution of biological aerosol and a mixture of aliphatic and oxygenated compounds from biomass burning and traffic exhausts. The concurrent presence of ammonium and amines also suggested the presence of ammonium/aminium nitrate and sulfate secondary aerosol. The size-dependent origin of WSOC was further corroborated by the increasing δ13C abundance from -26.81 ± 0.18‰ for the smallest particles to -25.93 ± 0.31‰ for the largest particles and the relative

  4. Functional characterization of the water-soluble organic carbon of size-fractionated aerosol in the southern Mississippi Valley

    NASA Astrophysics Data System (ADS)

    Chalbot, M.-C. G.; Brown, J.; Chitranshi, P.; Gamboa da Costa, G.; Pollock, E. D.; Kavouras, I. G.

    2014-06-01

    The chemical content of water-soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for periods when carbonaceous aerosol was the most abundant particulate component. The WSOC accounted for 5% of particle mass for particles with dp > 0.96 μm and 10% of particle mass for particles with dp < 0.96 μm. Non-exchangeable aliphatic (H-C), unsaturated aliphatic (H-C-C=), oxygenated saturated aliphatic (H-C-O), acetalic (O-CH-O) and aromatic (Ar-H) protons were determined by proton nuclear magnetic resonance (1H-NMR). The total non-exchangeable organic hydrogen concentrations varied from 4.1 ± 0.1 nmol m-3 for particles with 1.5 < dp < 3.0 μm to 73.9 ± 12.3 nmol m-3 for particles with dp < 0.49 μm. The molar H / C ratios varied from 0.48 ± 0.05 to 0.92 ± 0.09, which were comparable to those observed for combustion-related organic aerosol. The R-H was the most abundant group, representing about 45% of measured total non-exchangeable organic hydrogen concentrations, followed by H-C-O (27%) and H-C-C= (26%). Levoglucosan, amines, ammonium and methanesulfonate were identified in NMR fingerprints of fine particles. Sucrose, fructose, glucose, formate and acetate were associated with coarse particles. These qualitative differences of 1H-NMR profiles for different particle sizes indicated the possible contribution of biological aerosols and a mixture of aliphatic and oxygenated compounds from biomass burning and traffic exhausts. The concurrent presence of ammonium and amines also suggested the presence of ammonium/aminium nitrate and sulfate secondary aerosol. The size-dependent origin of WSOC was further corroborated by the increasing δ13C abundance from -26.81 ± 0.18‰ for the smallest particles to -25.93 ± 0.31‰ for the largest

  5. Size-Resolved Identification, Characterization, and Quantification of Primary Biological Organic Aerosol at a European Rural Site.

    PubMed

    Bozzetti, Carlo; Daellenbach, Kaspar R; Hueglin, Christoph; Fermo, Paola; Sciare, Jean; Kasper-Giebl, Anneliese; Mazar, Yinon; Abbaszade, Gülcin; El Kazzi, Mario; Gonzalez, Raquel; Shuster-Meiseles, Timor; Flasch, Mira; Wolf, Robert; Křepelová, Adéla; Canonaco, Francesco; Schnelle-Kreis, Jürgen; Slowik, Jay G; Zimmermann, Ralf; Rudich, Yinon; Baltensperger, Urs; El Haddad, Imad; Prévôt, André S H

    2016-04-01

    Primary biological organic aerosols (PBOA) represent a major component of the coarse organic matter (OMCOARSE, aerodynamic diameter > 2.5 μm). Although this fraction affects human health and the climate, its quantification and chemical characterization currently remain elusive. We present the first quantification of the entire PBOACOARSE mass and its main sources by analyzing size-segregated filter samples collected during the summer and winter at the rural site of Payerne (Switzerland), representing a continental Europe background environment. The size-segregated water-soluble OM was analyzed by a newly developed offline aerosol mass spectrometric technique (AMS). Collected spectra were analyzed by three-dimensional positive matrix factorization (3D-PMF), showing that PBOA represented the main OMCOARSE source during summer and its contribution to PM10 was comparable to that of secondary organic aerosol. We found substantial cellulose contributions to OMCOARSE, which in combination with gas chromatography mass spectrometry molecular markers quantification, underlined the predominance of plant debris. Quantitative polymerase chain reaction (qPCR) analysis instead revealed that the sum of bacterial and fungal spores mass represented only a minor OMCOARSE fraction (<0.1%). X-ray photoelectron spectroscopic (XPS) analysis of C and N binding energies throughout the size fractions revealed an organic N increase in the PM10 compared to PM1 consistent with AMS observations. PMID:26900965

  6. Size-Resolved Identification, Characterization, and Quantification of Primary Biological Organic Aerosol at a European Rural Site.

    PubMed

    Bozzetti, Carlo; Daellenbach, Kaspar R; Hueglin, Christoph; Fermo, Paola; Sciare, Jean; Kasper-Giebl, Anneliese; Mazar, Yinon; Abbaszade, Gülcin; El Kazzi, Mario; Gonzalez, Raquel; Shuster-Meiseles, Timor; Flasch, Mira; Wolf, Robert; Křepelová, Adéla; Canonaco, Francesco; Schnelle-Kreis, Jürgen; Slowik, Jay G; Zimmermann, Ralf; Rudich, Yinon; Baltensperger, Urs; El Haddad, Imad; Prévôt, André S H

    2016-04-01

    Primary biological organic aerosols (PBOA) represent a major component of the coarse organic matter (OMCOARSE, aerodynamic diameter > 2.5 μm). Although this fraction affects human health and the climate, its quantification and chemical characterization currently remain elusive. We present the first quantification of the entire PBOACOARSE mass and its main sources by analyzing size-segregated filter samples collected during the summer and winter at the rural site of Payerne (Switzerland), representing a continental Europe background environment. The size-segregated water-soluble OM was analyzed by a newly developed offline aerosol mass spectrometric technique (AMS). Collected spectra were analyzed by three-dimensional positive matrix factorization (3D-PMF), showing that PBOA represented the main OMCOARSE source during summer and its contribution to PM10 was comparable to that of secondary organic aerosol. We found substantial cellulose contributions to OMCOARSE, which in combination with gas chromatography mass spectrometry molecular markers quantification, underlined the predominance of plant debris. Quantitative polymerase chain reaction (qPCR) analysis instead revealed that the sum of bacterial and fungal spores mass represented only a minor OMCOARSE fraction (<0.1%). X-ray photoelectron spectroscopic (XPS) analysis of C and N binding energies throughout the size fractions revealed an organic N increase in the PM10 compared to PM1 consistent with AMS observations.

  7. Earth Science With the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station

    NASA Technical Reports Server (NTRS)

    Zawodny, Joe; Vernier, Jean-Paul; Thomason, Larry; Roell, Marilee; Pitts, Mike; Moore, Randy; Hill, Charles; Flittner, David; Damadeo, Rob; Cisewski, Mike

    2015-01-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) III is the fourth generation of solar occultation instruments operated by NASA, the first coming under a different acronym, to investigate the Earth's upper atmosphere. Three flight-ready SAGE III instruments were built by Ball Aerospace in the late 1990s, with one launched aboard the former Russian Aviation and Space Agency (now known as Roskosmos) Meteor-3M platform on 10 December 2001 (continuing until the platform lost power in 2006). Another of the original instruments was manifested for the ISS in the 2004 time frame, but was delayed because of budgetary considerations. Fortunately, that SAGE III/ISS mission was restarted in 2009 with a major focus upon filling an anticipated gap in ozone and aerosol observation in the second half of this decade. Here we discuss the mission architecture, its implementation, and data that will be produced by SAGE III/ISS, including their expected accuracy and coverage. The 52-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with excellent coverage of low and mid-latitudes. This is similar to that of the SAGE II mission (1985-2005), whose data set has served the international atmospheric science community as a standard for stratospheric ozone and aerosol measurements. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. Though in the visible portion of the spectrum the brightness of the Sun is one million times that of the full Moon, the SAGE III instrument is designed to cover this large dynamic range and also perform lunar occultations on a routine basis to augment the solar products. The standard lunar products were demonstrated during the SAGE III/M3M mission and include ozone, nitrogen dioxide & nitrogen trioxide. The operational flexibility of the SAGE III spectrometer accomplishes

  8. Aerosol acidity characterization of large metropolitan areas: Pilot and planning for Philadelphia

    SciTech Connect

    Waldman, J.M.; Koutrakis, P.; Burton, R.; Wilson, W.E.; Purdue, L.J.

    1993-01-01

    The report described the EPA's multi-year program to investigate the specific issues surrounding human exposures to aerosol activity. Philadelphia, a large metropolitan area in the heart of the northeastern seaboard afflicted with photochemical regional smog during the summertime, was chosen as the first city in the program. A pilot study of ambient concentrations was conducted in July 1991. An annular denuder system (ADS) sampler was operated for two weeks near downtown Philadelphia, with a second unit operated in central, suburban New Jersey, the same location of measurements in past years. The Philadelphia site was found to have higher concentrations of most major aerosol species, ammonia and acidic particles than in New Jersey, showing that aerosol neutralization within the urban center will not necessarily totally eliminate acidic particle exposures.

  9. Characterization of tropospheric desert aerosols at solar wavelengths by multispectral radiometry from Landsat

    USGS Publications Warehouse

    Otterman, Joseph; Fraser, R. S.; Bahethi, O. P.

    1982-01-01

    Characteristics of tropospheric desert aerosols are derived by comparing nadir spectral reflectivities computed from the radiative transfer models with reflectivities measured from Landsat. Over the ocean, reflectivities are compared, but over land the comparison is carried out by determining the ratios of the nadir reflectivity of the surface-atmosphere system over heavy aerosol concentration to the reflectivity of the underlying surface. This remote sensing technique is found to be a sensitive approach for measuring n2, the imaginary part of the refractive index. The desert aerosols under study, in the Iran and Pakistan area, are essentially pure scatterers, inasmuch as an n2 value of 0.001±0.001 was determined for each of the four Landsat spectral bands, that is, for a spectral interval from 0.5 to 1.1 μm.

  10. Aerosol characterization study using multi-spectrum remote sensing measurement techniques.

    SciTech Connect

    Glen, Crystal Chanea; Sanchez, Andres L.; Lucero, Gabriel Anthony; Schmitt, Randal L.; Johnson, Mark S.; Tezak, Matthew S; Servantes, Brandon Lee

    2013-09-01

    A unique aerosol flow chamber coupled with a bistatic LIDAR system was implemented to measure the optical scattering cross sections and depolarization ratio of common atmospheric particulates. Each of seven particle types (ammonium sulfate, ammonium nitrate, sodium chloride, potassium chloride, black carbon and Arizona road dust) was aged by three anthropogenically relevant mechanisms: 1. Sulfuric acid deposition, 2. Toluene ozonolysis reactions, and 3. m-Xylene ozonolysis reactions. The results of pure particle scattering properties were compared with their aged equivalents. Results show that as most particles age under industrial plume conditions, their scattering cross sections are similar to pure black carbon, which has significant impacts to our understanding of aerosol impacts on climate. In addition, evidence emerges that suggest chloride-containing aerosols are chemically altered during the organic aging process. Here we present the direct measured scattering cross section and depolarization ratios for pure and aged atmospheric particulates.

  11. Special issue: Chemical characterization of secondary organic aerosol - Dedication to Professor Magda Claeys

    NASA Astrophysics Data System (ADS)

    Surratt, Jason D.; Szmigielski, Rafal; Faye McNeill, V.

    2016-04-01

    Atmospheric aerosols are suspensions of liquid and solid particles that have diameters ranging from a few nanometers to several micrometers (μm). Atmospheric fine particulate matter (PM2.5, aerosols with aerodynamic diameters of 2.5 μm or less) are especially important since they can adversely affect air quality and human health as well as play a critical role in Earth's climate system. In terms of aerosol climate effects, PM2.5 can directly affect climate by scattering or absorbing incoming solar radiation or indirectly by acting as nuclei on which cloud droplets and ice particles form. As a result, a better understanding of processes that determine the formation and sinks of PM2.5 is needed for developing effective policies that improve air quality and public health as well as to accurately predict the response of the climate system due to changes in anthropogenic emissions.

  12. Characterization of vehicle emissions in São Paulo and the impacts on atmospheric chemistry and secondary aerosol formation

    NASA Astrophysics Data System (ADS)

    Ferreira De Brito, J.; Godoy, M.; Godoy, J.; Varanda Rizzo, L.; Artaxo, P.

    2012-12-01

    Megacities emissions are increasingly becoming a global issue, where emissions from the transportation sector play an important role. São Paulo, located in Southeast of Brazil, is a megacity with a population of 18 million people, 7 million cars and large-scale industrial emissions. As a result of the vehicular and industrial emissions, the air quality in São Paulo is considered one of the worst worldwide. Despite the large impact on human health and atmospheric chemistry/dynamics, many uncertainties are found on gas- and particulate matter vehicular emission factors and their following atmospheric processes, e.g. secondary organic aerosol formation. Due to the uniqueness of the vehicular fuel in Brazil, largely based on ethanol use, such characterization currently holds further uncertainties. To improve the understanding of the role of this unique emission pattern, we are running a source apportionment study in São Paulo. One of the goals of this study is a quantitative aerosol source apportionment focused on vehicular emissions, including ethanol and gasohol (both fuels used by light-duty vehicles) and diesel (heavy-duty vehicles). Whereas the latter shows usually much higher emission factors compared with ethanol or gasohol, heavy-duty vehicles have increasingly limited access within the São Paulo city limits, thus increasing the importance of light duty vehicles on air quality degradation. This study comprises four sampling sites, where trace elements and organic aerosol are being measured for PM2.5 and PM10 along with real-time NOx, ozone, PM10 and CO measurements. Aerosol optical properties and size distribution are being measured on a rotation basis between sampling stations. Furthermore, a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) and an Aerosol Chemical Speciation Monitor (ACSM) are used to real-time VOC analysis and aerosol composition, respectively. Results show aerosol number concentrations ranging between 10^4 and 3.10^4 cm-3, mostly

  13. Characterization of the sources and processes of organic and inorganic aerosols in New York city with a high-resolution time-of-flight aerosol mass apectrometer

    NASA Astrophysics Data System (ADS)

    Sun, Y.-L.; Zhang, Q.; Schwab, J. J.; Demerjian, K. L.; Chen, W.-N.; Bae, M.-S.; Hung, H.-M.; Hogrefe, O.; Frank, B.; Rattigan, O. V.; Lin, Y.-C.

    2011-02-01

    Submicron aerosol particles (PM1) were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer during the summer 2009 Field Intensive Study at Queens College in New York, NY. Organic aerosol (OA) and sulfate are the two dominant species, accounting for 54% and 24%, respectively, of the total PM1 mass. The average mass-based size distribution of OA presents a small mode peaking at ~150 nm (Dva) and an accumulation mode (~550 nm) that is internally mixed with sulfate, nitrate, and ammonium. The diurnal cycles of both sulfate and OA peak between 01:00-02:00 p.m. EST due to photochemical production. The average (±σ) oxygen-to-carbon (O/C), hydrogen-to-carbon (H/C), and nitrogen-to-carbon (N/C) ratios of OA in NYC are 0.36 (±0.09), 1.49 (±0.08), and 0.012 (±0.005), respectively, corresponding to an average organic mass-to-carbon (OM/OC) ratio of 1.62 (±0.11). Positive matrix factorization (PMF) of the high resolution mass spectra identified two primary OA (POA) sources, traffic and cooking, and three secondary OA (SOA) components including a highly oxidized, regional low-volatility oxygenated OA (LV-OOA; O/C = 0.63), a less oxidized, semi-volatile SV-OOA (O/C = 0.38) and a unique nitrogen-enriched OA (NOA; N/C = 0.053) characterized with prominent CxH2x + 2N+ peaks likely from amino compounds. Our results indicate that cooking and traffic are two distinct and mass-equivalent POA sources in NYC, together contributing ~30% of the total OA mass during this study. The OA composition is dominated by secondary species, especially during high PM events. SV-OOA and LV-OOA on average account for 34% and 30%, respectively, of the total OA mass. The chemical evolution of SOA in NYC appears to progress with a continuous oxidation from SV-OOA to LV-OOA, which is further supported by a gradual increase of O/C ratio and a simultaneous decrease of H/C ratio in total OOA. Detailed analysis of NOA (5.8% of OA) presents evidence that organic nitrogen

  14. Characterization of a real-time tracer for Isoprene Epoxydiols-derived Secondary Organic Aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

    NASA Astrophysics Data System (ADS)

    Hu, W. W.; Campuzano-Jost, P.; Palm, B. B.; Day, D. A.; Ortega, A. M.; Hayes, P. L.; Krechmer, J. E.; Chen, Q.; Kuwata, M.; Liu, Y. J.; de Sá, S. S.; Martin, S. T.; Hu, M.; Budisulistiorini, S. H.; Riva, M.; Surratt, J. D.; St. Clair, J. M.; Isaacman-Van Wertz, G.; Yee, L. D.; Goldstein, A. H.; Carbone, S.; Artaxo, P.; de Gouw, J. A.; Koss, A.; Wisthaler, A.; Mikoviny, T.; Karl, T.; Kaser, L.; Jud, W.; Hansel, A.; Docherty, K. S.; Robinson, N. H.; Coe, H.; Allan, J. D.; Canagaratna, M. R.; Paulot, F.; Jimenez, J. L.

    2015-04-01

    isoprene. We introduce a graphical diagnostic to study the presence and aging of IEPOX-SOA as a "triangle plot" of fCO2 vs. fC5H6O. Finally, we develop a simplified method to estimate ambient IEPOX-SOA mass concentrations, which is shown to perform well compared to the full PMF method. The uncertainty of the tracer method is up to a factor of ~ 2 if the fC5H6O of the local IEPOX-SOA is not available. When only unit mass resolution data is available, as with the aerosol chemical speciation monitor (ACSM), all methods may perform less well because of increased interferences from other ions at m/z 82. This study clarifies the strengths and limitations of the different AMS methods for detection of IEPOX-SOA and will enable improved characterization of this OA component.

  15. Characterization of the sources and processes of organic and inorganic aerosols in New York City with a high-resolution time-of-flight aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Sun, Y.-L.; Zhang, Q.; Schwab, J. J.; Demerjian, K. L.; Chen, W.-N.; Bae, M.-S.; Hung, H.-M.; Hogrefe, O.; Frank, B.; Rattigan, O. V.; Lin, Y.-C.

    2010-10-01

    peaking around local lunch and dinner times. In addition, NOA is characterized with prominent CxH2x+2N+ peaks likely from amine compounds. Our results indicate that cooking-related activities are a major source of POA in NYC, releasing comparable amounts of POA as traffic emissions. POA=HOA+COA) on average accounts for ~30% of the total OA mass during this study while SOA dominates the OA composition with SV-OOA and LV-OOA on average accounting for 34% and 30%, respectively, of the total OA mass. The chemical evolution of SOA in NYC involves a~continuous oxidation from SV-OOA to LV-OOA, which is further supported by a gradual increase of O/C ratio and a simultaneous decrease of H/C ratio in total OOA. Detailed analysis of NOA (5.8% of OA) presents evidence that nitrogen-containing organic species such as amines might have played an important role in the atmospheric processing of OA in NYC, likely involving acid-base chemistry. Analysis of air mass trajectories and satellite imagery of aerosol optical depth (AOD) indicates that the high potential source regions of secondary sulfate and aged OA are mainly located in regions to the west and southwest of the city.

  16. Characterization of a real-time tracer for Isoprene Epoxydiols-derived Secondary Organic Aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

    DOE PAGES

    Hu, W. W.; Campuzano-Jost, P.; Palm, B. B.; Day, D. A.; Ortega, A. M.; Hayes, P. L.; Krechmer, J. E.; Chen, Q.; Kuwata, M.; Liu, Y. J.; et al

    2015-04-16

    from isoprene. We introduce a graphical diagnostic to study the presence and aging of IEPOX-SOA as a "triangle plot" of fCO2 vs. fC5H6O. Finally, we develop a simplified method to estimate ambient IEPOX-SOA mass concentrations, which is shown to perform well compared to the full PMF method. The uncertainty of the tracer method is up to a factor of ~ 2 if the fC5H6O of the local IEPOX-SOA is not available. When only unit mass resolution data is available, as with the aerosol chemical speciation monitor (ACSM), all methods may perform less well because of increased interferences from other ions at m/z 82. This study clarifies the strengths and limitations of the different AMS methods for detection of IEPOX-SOA and will enable improved characterization of this OA component.« less

  17. Characterization of the physical, chemical, and optical properties of atmospheric aerosol particles in New Hampshire

    NASA Astrophysics Data System (ADS)

    Slater, John Frederick

    Tropospheric aerosol particles directly affect the radiative budget of the Earth, and degrade visibility, by scattering and absorbing short-wavelength solar radiation. However, the radiative effect of aerosols is highly uncertain due to the non-uniform spatial distribution of the particles over Earth, their heterogeneous chemical composition, and their variable size. This dissertation quantifies some of the physical, chemical, and optical (radiative) properties of aerosols at different locations within New Hampshire (NH) from spring 2000 to fall 2001. During spring 2000, a 1-month study conducted at a mountaintop location adjacent to the White Mountain National Forest in northern NH showed that synoptic-scale air mass transport heavily influenced aerosol properties, and hence regional visibility. During W/SW flow, aerosol parameters and haziness were generally twice as high as times of N/NE flow. Similar transport dependent results were observed in October 2000 during a regional pollution event. Pollutants built-up in concentration during 22--28 October, culminated on 28 October, and then dropped 10-fold to background levels within a 6-hour period. Synoptic weather conditions during the transition from high to low pollutant levels indicated that an intense frontal boundary traversed the region, serving as a divide between a warm, humid, and polluted air mass from the W/SW, and a cold, dry, and clean air mass advancing out of Canada. Further work connecting air mass transport and aerosol variability in southern NH revealed that maximum aerosol optical depth (AOD) occurred in summer and was primarily associated with W/SW flow. Minimum AOD occurred in winter and was generally associated with N/NE flow. Mass scattering and absorption efficiencies of PM2.5 did not vary significantly between times of transport from different source regions and were very close to theoretical values. Maximum positive values of aerosol direct radiative forcing occurred in winter and maximum

  18. Use of Cavity Ring Down Spectroscopy to Characterize Organic Acids and Aerosols Emitted in Biomass Burning

    NASA Astrophysics Data System (ADS)

    Bililign, Solomon; Fiddler, Marc; Singh, Sujeeta

    2012-02-01

    One poorly understood, but significant class of volatile organic compounds (VOC) present in biomass burning is gas-phase organic acids and inorganic acids. These acids are extremely difficult to measure because of their adsorptive nature. Particulates and aerosols are also produced during biomass burning and impact the radiation budget of the Earth and, hence, impact global climate. Use cavity ring down spectroscopy (CRD) to measure absorption cross sections for OH overtone induced photochemistry in some organic acids (acetic acid and peracetic acid) will be presented and planed measurements of optical properties of aerosols composed of mixtures of different absorbing and non-absorbing species using CRD will be discussed.

  19. A new comprehensive approach to characterizing carbonaceous aerosol with an application to wintertime Fresno, California PM2.5

    USGS Publications Warehouse

    Herckes, P.; Leenheer, J.A.; Collett, J.L.

    2007-01-01

    Fine particulate matter (PM2.5) samples were collected during a three week winter period in Fresno (CA). A composite sample was characterized by isolating several distinct fractions and characterizing them by infrared and nuclear magnetic resonance (NMR) spectroscopy. More than 80% of the organic matter in the aerosol samples was recovered and characterized. Only 35% of the organic matter was water soluble with another third soluble in dichloromethane and the remainder insoluble. Within the isolated water soluble material, hydro