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Sample records for atmospheric aerosol desarrollo

  1. Atmospheric and aerosol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    McNeill, V. Faye [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering; Ariya, Parisa A. (ed.) [McGill Univ. Montreal, QC (Canada). Dept. of Chemistry; McGill Univ. Montreal, QC (Canada). Dept. of Atmospheric and Oceanic Sciences

    2014-09-01

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  2. Development of Methodologies from Determination of Organic Components from Atmospheric Aerosol; Desarrollo de Metodologias para la Determinacion de Componentes Organicos del Aerosol Atmosferico

    Energy Technology Data Exchange (ETDEWEB)

    Pindado, O.; Perez, R.; Garcia, R.; Barrado, A. I.; Sevillano, M. L.; Gonzalez, D.

    2006-07-01

    It is presented method for the organic compound determination, such as n-alkanes, PAH's, alcohols and fatty acids that are comprised the particulate matter of aerosol. The procedure is based on sampling the particulate matter over quartz fibre filters that will be extracted by means of the Soxhiet technique, and later they will be divided by means of silicagel column. PAH's is analyzed by means of HPLCm whereas the rest is analyzed by GC-MS and for it, acids and alcohol must be previously derivatized with BSTFA.12 samples took shelter of fractions PMIO and PM2.5 of the aerosol of country side like application of the method. (Author) 60 refs.

  3. Atmosphere aerosol satellite project Aerosol-UA

    Science.gov (United States)

    Milinevsky, Gennadi; Yatskiv, Yaroslav; Syniavskyi, Ivan; Bovchaliuk, Andrii; Degtyaryov, Oleksandr; Sosonkin, Mikhail; Mishchenko, Michael; Danylevsky, Vassyl; Ivanov, Yury; Oberemok, Yevgeny; Masley, Volodymyr; Rosenbush, Vera; Moskalev, Sergii

    2017-04-01

    The experiment Aerosol-UA is Ukrainian space mission aimed to the terrestrial atmospheric aerosol spatial distribution and microphysics investigations. The experiment concept is based on idea of Glory/APS mission of precise orbital measurements of polarization and intensity of the sunlight scattered by the atmosphere, aerosol and the surface the multichannel Scanning Polarimeter (ScanPol) with narrow field-of-view. ScanPol measurements will be accompanied by the wide-angle MultiSpectral Imager-Polarimeter (MSIP). The ScanPol is designed to measure Stokes parameters I, Q, U within the spectral range from the UV to the SWIR in a wide range of phase angles along satellite ground path. Expected ScanPol polarimetric accuracy is 0.15%. A high accuracy measurement of the degree of linear polarization is provided by on-board calibration of the ScanPol polarimeter. On-board calibration is performed for each scan of the mirror scanning system. A set of calibrators is viewed during the part of the scan range when the ScanPol polarimeter looks in the direction opposite to the Earth's surface. These reference assemblies provide calibration of the zero of the polarimetric scale (unpolarized reference assembly) and the scale factor for the polarimetric scale (polarized reference assembly). The zero of the radiometric scale is provided by the dark reference assembly.The spectral channels of the ScanPol are used to estimate the tropospheric aerosol absorption, the aerosol over the ocean and the land surface, the signals from cirrus clouds, stratospheric aerosols caused by major volcanic eruptions, and the contribution of the Earth's surface. The imager-polarimeter MSIP will collect 60°x60° field-of-view images on the state of the atmosphere and surface in the area, where the ScanPol polarimeter will measure, to retrieve aerosol optical depth and polarization properties of aerosol by registration of three Stokes parameters simultaneously in three spectral channels. The two more

  4. SMEX02 Atmospheric Aerosol Optical Properties Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of observations of atmospheric parameters including spectral aerosol optical depths, precipitable water, sky radiance distributions and...

  5. Toxicity of atmospheric aerosols on marine phytoplankton.

    Science.gov (United States)

    Paytan, Adina; Mackey, Katherine R M; Chen, Ying; Lima, Ivan D; Doney, Scott C; Mahowald, Natalie; Labiosa, Rochelle; Post, Anton F

    2009-03-24

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus. We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere-ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia.

  6. Atmospheric aerosol light scattering and polarization peculiarities

    CERN Document Server

    Patlashenko, Zh I

    2015-01-01

    This paper considers environmental problems of natural and anthropogenic atmospheric aerosol pollution and its global and regional monitoring. Efficient aerosol investigations may be achieved by spectropolarimetric measurements. Specifically second and fourth Stokes parameters spectral dependencies carry information on averaged refraction and absorption indexes and on particles size distribution functions characteristics.

  7. Improvements in Aerosol Retrieval for Atmospheric Correction

    Science.gov (United States)

    2008-07-01

    spherical albedo of the atmosphere from the ground, L*a is the radiance backscattered by the atmosphere, and a and b are coefficients that solely...extinction, the scattering albedo for each scattering event and the value of the scattering phase function. For a stratified atmosphere, the phase function...The MODIS 2.1-μm Channel-Correlation with Visible Reflectance for Use in Remote Sensing of Aerosol,” IEEE Trans. Geosci. Remote Sens., 35, 1286

  8. Aerosolization and Atmospheric Transformation of Engineered Nanoparticles

    Science.gov (United States)

    Tiwari, Andrea J.

    While research on the environmental impacts of engineered nanoparticles (ENPs) is growing, the potential for them to be chemically transformed in the atmosphere has been largely ignored. The overall objective of this work was to assess the atmospheric transformation of carbonaceous nanoparticles (CNPs). The research focuses on C60 fullerene because it is an important member of the carbonaceous nanoparticle (CNP) family and is used in a wide variety of applications. The first specific objective was to review the potential of atmospheric transformations to alter the environmental impacts of CNPs. We described atmospheric processes that were likely to physically or chemically alter aerosolized CNPs and demonstrated their relevance to CNP behavior and toxicity in the aqueous and terrestrial environment. In order to investigate the transformations of CNP aerosols under controlled conditions, we developed an aerosolization technique that produces nano-scale aerosols without using solvents, which can alter the surface chemistry of the aerosols. We demonstrated the technique with carbonaceous (C60) and metal oxide (TiO2, CeO2) nanoparticle powders. All resulting aerosols exhibited unimodal size distributions and mode particle diameters below 100 nm. We used the new aerosolization technique to investigate the reaction between aerosolized C60 and atmospherically realistic levels of ozone (O3) in terms of reaction products, reaction rate, and oxidative stress potential. We identified C60O, C60O2, and C60O3 as products of the C60-O3 reaction. We demonstrated that the oxidative stress potential of C 60 may be enhanced by exposure to O3. We found the pseudo-first order reaction rate to be 9 x 10-6 to 2 x 10 -5 s-1, which is several orders of magnitude lower than the rate for several PAH species under comparable conditions. This research has demonstrated that a thorough understanding of atmospheric chemistry of ENPs is critical for accurate prediction of their environmental

  9. Ionic Surface Active Compounds in Atmospheric Aerosols

    Directory of Open Access Journals (Sweden)

    Jariya Sukhapan

    2002-01-01

    Full Text Available Surfactants in the atmosphere have several potential roles in atmospheric chemistry. They can form films on aqueous surfaces, which lowers the surface tension and possibly delays water evaporation and gaseous transportation across the aqueous interface. They can also increase the solubility of organic compounds in the aqueous phase. Recently, the decrease of surface tension in cloud growing droplets has been suggested as relevant to increases in the number of droplets of smaller size, potentially enhancing cloud albedo. Natural surfactants in the lung aid gas transfer and influence the dissolution rate of aerosol particles, so surfactants in atmospheric aerosols, once inhaled, may interact with pulmonary surfactants. Ambient aerosols were collected from the edge of Norwich, a small city in a largely agricultural region of England, and analysed for surfactants. Methylene blue, a conventional dye for detecting anionic surfactants, has been used as a colorimetric agent. The concentration of surfactants expressed as methylene blue active substances (MBAS is in the range of 6–170 pmol m-3(air. A negative correlation with chloride aerosol indicates that these surfactants are probably not the well-known surfactants derived from marine spray. A more positive correlation with aerosol nitrate and gaseous NOx supports an association with more polluted inland air masses. The surfactants found in aerosols seem to be relatively strong acids, compared with weaker acids such as the long-chain carboxylic acids previously proposed as atmospheric surfactants. Surfactants from the oxidation of organic materials (perhaps vegetation- or soil-derived seem a likely source of these substances in the atmosphere.

  10. Modification of combustion aerosols in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Weingartner, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-07-01

    Combustion aerosols particles are released on large scale into the atmosphere in the industrialized regions as well as in the tropics (by wood fires). The particles are subjected to various aging processes which depend on the size, morphology, and chemical composition of the particles. The interaction of combustion particles with sunlight and humidity as well as adsorption and desorption of volatile material to or from the particles considerably changes their physical and chemical properties and thus their residence time in the atmosphere. This is of importance because combustion particles are known to have a variety of health effects on people. Moreover, atmospheric aerosol particles have an influence on climate, directly through the reflection and absorption of solar radiation and indirectly through modifying the optical properties and lifetime of clouds. In a first step, a field experiment was carried out to study the sources and characteristics of combustion aerosols that are emitted from vehicles in a road tunnel. It was found that most of the fine particles were tail pipe emissions of diesel powered vehicles. The calculation shows that on an average these vehicles emit about 300 mg fine particulate matter per driven kilometer. This emission factor is at least 100 times higher than the mean emission factor estimated for gasoline powered vehicles. Furthermore, it is found that during their residence time in the tunnel, the particles undergo significant changes: The particles change towards a more compact structure. The conclusion is reached that this is mainly due to adsorption of volatile material from the gas phase to the particle surface. In the atmosphere, the life cycle as well as the radiative and chemical properties of an aerosol particle is strongly dependent on its response to humidity. Therefore the hygroscopic behavior of combustion particles emitted from single sources (i.e. from a gasoline and a diesel engine) were studied in laboratory experiments.

  11. SMEX05 Atmospheric Aerosol Optical Properties Data: Iowa

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains observations of atmospheric parameters from aerosol optical property measurements collected during the Soil Moisture Experiment 2005 (SMEX05)...

  12. SMEX03 Atmospheric Aerosol Optical Properties Data: Oklahoma

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of observations of atmospheric parameters including spectral aerosol optical depths, precipitable water, sky radiance distributions and...

  13. SMEX04 Atmospheric Aerosol Optical Properties Data: Arizona

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains observations of atmospheric parameters from aerosol optical property measurements collected during the Soil Moisture Experiment 2004 (SMEX04)...

  14. Ultrafine atmospheric aerosols, clouds and climate

    Science.gov (United States)

    Pierce, Jeffrey Robert

    Changes in atmospheric aerosol due to anthropogenic emissions are the most uncertain factors that have contributed to recent climate change. Much of this uncertainty is from the effect that particles have on cloud radiative properties, the aerosol indirect effect. Particles on which cloud droplets form are called cloud condensation nuclei (CCN). Particles larger than about 80--100 nm dry diameter typically act as CCN in stratus clouds. In order to predict how cloud radiative properties have changed since pre-industrial times, the CCN concentrations in both present-day and pre-industrial times must be known. Much of the uncertainty in CCN predictions is from uncertainty in the sources of ultrafine particles (particles with diameter smaller than 100 nm) as well as the processes that grow these particles to CCN sizes. This thesis explores various aspects of the how uncertainties in ultrafine particles affect predictions of CCN. First, we explore the uncertainty in CCN due to uncertain sea-salt emissions and also the affect of recently quantified ultrafine sea-salt on CCN. In the Southern Ocean, uncertainty in sea-salt emissions contributed to uncertainties in CCN(0.2%) by a factor of 2. Ultrafine sea-salt aerosol increased CCN(0.2%) in remote marine regions by more than 20%. Next, we look at how primary carbonaceous particles affect CCN as well as how uncertainties in their chemical properties affect CCN. The addition of primary carbonaceous aerosol increased CCN(0.2%) concentrations by 65--90% in the globally averaged surface layer. A sensitivity study showed that approximately half of this increase occurs even if all carbonaceous aerosols are completely insoluble. To study the growth of ultrafine particles to CCN sizes, we develop the Probability of Ultrafine Growth (PUG) model. It was found in most cases that condensation is the dominant growth mechanism and coagulation with larger particles is the dominant sink mechanism for ultrafine particles. We found that the

  15. Determination of atmospheric aerosol properties over land using satellite measurements

    NARCIS (Netherlands)

    Kokhanovsky, A.A.; Leeuw, G. de

    2009-01-01

    Mostly, aerosol properties are poorly understood because the aerosol properties are very sparse. The first workshop on the determination of atmospheric aerosol properties over land using satellite measurements is convened in Bremen, Germany. In this workshop, the topics of discussions included a

  16. Vapor scavenging by atmospheric aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, E.

    1996-05-01

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

  17. Spectroscopic Studies of Atmospheric Aerosol Chemistry

    Science.gov (United States)

    Wamsley, R.; Leather, K.; Horn, A. B.; Percival, C.

    2008-12-01

    Particles are ubiquitous in the troposphere and are involved in chemical and physical processes affecting the composition of the atmosphere, climate, cloud albedo and human health (Finlayson-Pitts and Pitts, 2000). Organic species, such as alcohols, carboxylic acids, ketones, aldehydes, aromatics, alkenes and alkanes, originate both from anthropogenic and natural sources and comprise a large component of atmospheric particles. Gas-phase species, such as ozone, can oxidize these organics, changing the particle's oxygen-to carbon ratio and potentially altering its hygroscopicity, viscosity, morphology and reactivity. One reaction in particular, that between ozone and oleic acid, has been the focus of several recent studies and extensively researched by Ziemann (2005). Oleic acid reacts readily with ozone and has a low vapor pressure making this reaction convenient to study in the laboratory and has become the benchmark for studying heterogeneous reactions representing the oxidative processing of atmospheric organic aerosols. A critical source of uncertainty in reactivity estimates is a lack of understanding of the mechanism through which some VOCs are oxidized. This knowledge gap is especially critical for aromatic compounds. Because the intermediate reaction steps and products of aromatics oxidation are unknown, chemical mechanisms incorporate parameters estimated from environmental chamber experiments to represent their overall contribution to ozone formation, e.g. Volkamer et al. ( 2006). Previous studies of uncertainties in incremental reactivity estimates for VOCs found that the representation of aromatics chemistry contributed significantly to the estimated 40 - 50% uncertainties in the incremental reactivities of common aromatic compounds Carter et al. (2002). This study shows development of an effective IR method that can monitor the reaction and hence obtain the kinetics of the ozonolysis of an aromatic compound in the aerosol phase. The development of such

  18. Procedure Development to Determine Organic Compounds in the PM{sub 1}-2.5 and PM{sub 2}.5-10 Fractions of Atmospheric Aerosols; Desarrollo de la Metodologia para la Determinacion de los Compuestos Organicos en las Fracciones PM{sub 1}-2.5 y PM{sub 2}.5-10 del Aerosol Atmosferico

    Energy Technology Data Exchange (ETDEWEB)

    Pindado, O.; Perez, R. M.

    2011-07-28

    An analytical procedure development to measure organic compounds such as aliphatic hydrocarbons, polycyclic aromatic compounds, n-alcohols and fatty acids in PM{sub 1}-2.5 and PM{sub 2}.5-10 of atmospheric aerosol is accomplished. The development encompasses an optimization of extraction step, derivatization step and chromatographic analysis. The method developed consists in a microwave extraction, followed by a stage of fractionation and analysis by GC/MS. (Author) 20 refs.

  19. Origins of atmospheric aerosols. Basic concepts on aerosol main physical properties; L`aerosol atmospherique: ses origines quelques notions sur les principales proprietes physiques des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Renoux, A. [Paris-12 Univ., 94 - Creteil (France). Laboratoire de Physique des aerosols et de transferts des contaminations

    1996-12-31

    Natural and anthropogenic sources of atmospheric aerosols are reviewed and indications of their concentrations and granulometry are given. Calculation of the lifetime of an atmospheric aerosol of a certain size is presented and the various modes of aerosol granulometry and their relations with photochemical and physico-chemical processes in the atmosphere are discussed. The main physical, electrical and optical properties of aerosols are also presented: diffusion coefficient, dynamic mobility and relaxation time, Stokes number, limit rate of fall, electrical mobility, optical diffraction

  20. SPEX: a highly accurate spectropolarimeter for atmospheric aerosol characterization

    Science.gov (United States)

    Rietjens, J. H. H.; Smit, J. M.; di Noia, A.; Hasekamp, O. P.; van Harten, G.; Snik, F.; Keller, C. U.

    2017-11-01

    Global characterization of atmospheric aerosol in terms of the microphysical properties of the particles is essential for understanding the role aerosols in Earth climate [1]. For more accurate predictions of future climate the uncertainties of the net radiative forcing of aerosols in the Earth's atmosphere must be reduced [2]. Essential parameters that are needed as input in climate models are not only the aerosol optical thickness (AOT), but also particle specific properties such as the aerosol mean size, the single scattering albedo (SSA) and the complex refractive index. The latter can be used to discriminate between absorbing and non-absorbing aerosol types, and between natural and anthropogenic aerosol. Classification of aerosol types is also very important for air-quality and health-related issues [3]. Remote sensing from an orbiting satellite platform is the only way to globally characterize atmospheric aerosol at a relevant timescale of 1 day [4]. One of the few methods that can be employed for measuring the microphysical properties of aerosols is to observe both radiance and degree of linear polarization of sunlight scattered in the Earth atmosphere under different viewing directions [5][6][7]. The requirement on the absolute accuracy of the degree of linear polarization PL is very stringent: the absolute error in PL must be smaller then 0.001+0.005.PL in order to retrieve aerosol parameters with sufficient accuracy to advance climate modelling and to enable discrimination of aerosol types based on their refractive index for air-quality studies [6][7]. In this paper we present the SPEX instrument, which is a multi-angle spectropolarimeter that can comply with the polarimetric accuracy needed for characterizing aerosols in the Earth's atmosphere. We describe the implementation of spectral polarization modulation in a prototype instrument of SPEX and show results of ground based measurements from which aerosol microphysical properties are retrieved.

  1. The color of carbonaceous aerosols in the ambient atmosphere

    Science.gov (United States)

    Liu, C.; Chung, C.; Zhang, F.; Yin, Y.; Zhao, D.

    2016-12-01

    Biomass burning aerosols, i.e. carbonaceous aerosols, mainly consist of black carbon (BC) and organic aerosols (OAs). Most OAs are non-absorptive, whereas some, e.g. brown carbon (BrC), can also significantly absorb solar radiation. However, the BC and BrC show quite different spectral habits on the absorption, and, thus, different colors. This presentation reveals the colors of carbonaceous aerosols in the ambient atmosphere. A combination of the particle scattering simulations, radiative transfer and RGB color model is used to display the color of an aerosol layer in the atmosphere, and BrC, BC and their mixture with scattering OAs are considered. Numerical results indicate that the color of the aerosol layer is substantially influenced by their absorption Ångström Exponent (AAE), not the species. Both the BCs and tar balls (TBs, a class of BrC) appear brownish at small particle sizes and becomes blackish at large sizes. At realistic size distributions, BCs look more blackish than TBs, but still exhibit some brown color. Meanwhile, if the aerosol layer absorbs over approximately 80% of the incident light (at green), all biomass burning aerosols become black in the atmosphere. The colors for mixture of purely scattering and absorptive carbonaceous aerosol layers in the atmosphere are also investigated. This study suggests that the brownishness of biomass burning aerosols indicates the amount of BC/BrC as well as the ratio of BC to BrC.

  2. Organic aerosol formation during the atmospheric degradation of toluene.

    Science.gov (United States)

    Hurley, M D; Sokolov, O; Wallington, T J; Takekawa, H; Karasawa, M; Klotz, B; Barnes, I; Becker, K H

    2001-04-01

    Organic aerosol formation during the atmospheric oxidation of toluene was investigated using smog chamber systems. Toluene oxidation was initiated by the UV irradiation of either toluene/air/NOx or toluene/air/CH3ONO/NO mixtures. Aerosol formation was monitored using scanning mobility particle sizers and toluene loss was monitored by in-situ FTIR spectroscopy or GC-FID techniques. The experimental results show that the reaction of OH radicals, NO3 radicals and/or ozone with the first generation products of toluene oxidation are sources of organic aerosol during the atmospheric oxidation of toluene. The aerosol results fall into two groups, aerosol formed in the absence and presence of ozone. An analytical expression for aerosol formation is developed and values are obtained for the yield of the aerosol species. In the absence of ozone the aerosol yield, defined as aerosol formed per unit toluene consumed once a threshold for aerosol formation has been exceeded, is 0.075 +/- 0.004. In the presence of ozone the aerosol yield is 0.108 +/- 0.004. This work provides experimental evidence and a simple theory confirming the formation of aerosol from secondary reactions.

  3. Atmospheric aerosol monitoring at the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Cester, R.; Chiosso, M.; Chirin, J.; Clay, R.; Dawson, B.; Fick, B.; Filipcic, A.; Garcia, B.; Grillo, A.; Horvat, M.; Iarlori, M.; Malek, M.; Matthews, J.; Matthews,; Melo, D.; Meyhandan, R.; Mostafa, M.; Mussa, R.; Prouza, M.; Raefert, B.; Rizi, V.

    2005-07-01

    For a ground based cosmic-ray observatory the atmosphere is an integral part of the detector. Air fluorescence detectors (FDs) are particularly sensitive to the presence of aerosols in the atmosphere. These aerosols, consisting mainly of clouds and dust, can strongly affect the propagation of fluorescence and Cherenkov light from cosmic-ray induced extensive air showers. The Pierre Auger Observatory has a comprehensive program to monitor the aerosols within the atmospheric volume of the detector. In this paper the aerosol parameters that affect FD reconstruction will be discussed. The aerosol monitoring systems that have been deployed at the Pierre Auger Observatory will be briefly described along with some measurements from these systems.

  4. A machine learning approach for predicting atmospheric aerosol size distributions

    Science.gov (United States)

    Rudiger, Joshua J.; Book, Kevin; deGrassie, John Stephen; Hammel, Stephen; Baker, Brooke

    2017-09-01

    An accurate model and parameterization of aerosol concentration is needed to predict the performance of electro-optical imaging systems. Current models have been shown to vary widely in their ability to accurately predict aerosol size distributions and subsequent scattering properties of the atmosphere. One of the more prevalent methods for modeling particle size spectra consists of fitting a modified gamma function to measurement data, however this limits the distribution to a single mode. Machine learning models have been shown to predict complex multimodal aerosol particle size spectra. Here we establish an empirical model for predicting aerosol size spectra using machine learning techniques. This is accomplished through measurements of aerosols size distributions over the course of eight months. The machine learning models are shown to extend the functionality of Advanced Navy Aerosol Model (ANAM), developed to model the size distribution of aerosols in the maritime environment.

  5. Physical and optical characteristics of atmospheric aerosols during ...

    Indian Academy of Sciences (India)

    seen in low altitude stations. These are attributed to the dynamics of the atmospheric boundary layer. ... 15 channels of composite aerosols, in the size range 0.3 to 20.0 µm. Automatic, portable, bat- ..... 6043–6058. Latha K M and Badarinath K V S 2003 Black carbon aerosols over tropical urban environment – A case study;.

  6. Physical and optical characteristics of atmospheric aerosols during ...

    Indian Academy of Sciences (India)

    Physical and optical characteristics of atmospheric aerosols during ICARB at Manora Peak, Nainital: A sparsely inhabited, high-altitude location in the Himalayas ... Total aerosol number concentration and BC mass concentration showed diurnal variation with a midnight and early morning minimum and a late afternoon ...

  7. Elemental analysis of atmospheric aerosols in Gaborone | Verma ...

    African Journals Online (AJOL)

    Aerosols are mixture of solid and liquid particles and have considerable variation in terms of their chemical composition and size. In this study the elemental composition of aerosol particles in the atmosphere of a city, Gaborone, was carried out. The elemental analysis was done by environmental scanning electron ...

  8. Mobile Atmospheric Aerosol and Radiation Characterization Observatory (MAARCO)

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: MAARCO is designed as a stand-alone facility for basic atmospheric research and the collection of data to assist in validating aerosol and weather models....

  9. Fractionation of Stable Isotopes in Atmospheric Aerosol Reactions

    DEFF Research Database (Denmark)

    Meusinger, Carl

    Aerosols - particles suspended in air - are the single largest uncertainty in our current understanding of Earth's climate. They also affect human health, infrastructure and ecosystems. Aerosols are emitted either directly into the atmosphere or are formed there for instance in response to chemical...... reactions and undergo complex chemical and physical changes during their lifetimes. In order to assess processes that form and alter aerosols, information provided by stable isotopes can be used to help constrain estimates on the strength of aerosol sources and sinks. This thesis studies (mass......-independent) fractionation processes of stable isotopes of C, N, O and S in order to investigate three different systems related to aerosols: 1. Post-depositional processes of nitrate in snow that obscure nitrate ice core records 2. Formation and aging of secondary organic aerosol generated by ozonolysis of X...

  10. Remote sensing for studying atmospheric aerosols in Malaysia

    Science.gov (United States)

    Kanniah, Kasturi D.; Kamarul Zaman, Nurul A. F.

    2015-10-01

    The aerosol system is Southeast Asia is complex and the high concentrations are due to population growth, rapid urbanization and development of SEA countries. Nevertheless, only a few studies have been carried out especially at large spatial extent and on a continuous basis to study atmospheric aerosols in Malaysia. In this review paper we report the use of remote sensing data to study atmospheric aerosols in Malaysia and document gaps and recommend further studies to bridge the gaps. Satellite data have been used to study the spatial and seasonal patterns of aerosol optical depth (AOD) in Malaysia. Satellite data combined with AERONET data were used to delineate different types and sizes of aerosols and to identify the sources of aerosols in Malaysia. Most of the aerosol studies performed in Malaysia was based on station-based PM10 data that have limited spatial coverage. Thus, satellite data have been used to extrapolate and retrieve PM10 data over large areas by correlating remotely sensed AOD with ground-based PM10. Realising the critical role of aerosols on radiative forcing numerous studies have been conducted worldwide to assess the aerosol radiative forcing (ARF). Such studies are yet to be conducted in Malaysia. Although the only source of aerosol data covering large region in Malaysia is remote sensing, satellite observations are limited by cloud cover, orbital gaps of satellite track, etc. In addition, relatively less understanding is achieved on how the atmospheric aerosol interacts with the regional climate system. These gaps can be bridged by conducting more studies using integrated approach of remote sensing, AERONET and ground based measurements.

  11. Carbonaceous aerosols influencing atmospheric radiation: Black and organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Penner, J.E. [Lawrence Livermore National Lab., CA (United States). Global Climate Research Div.

    1994-09-01

    Carbonaceous particles in the atmosphere may both scatter and absorb solar radiation. The fraction associated with the absorbing component is generally referred to as black carbon (BC) and is mainly produced from incomplete combustion processes. The fraction associated with condensed organic compounds is generally referred to as organic carbon (OC) or organic matter and is mainly scattering. Absorption of solar radiation by carbonaceous aerosols may heat the atmosphere, thereby altering the vertical temperature profile, while scattering of solar radiation may lead to a net cooling of the atmosphere/ocean system. Carbonaceous aerosols may also enhance the concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the fine particle (D < 2.5 {mu}m) source rates of both OC and BC. The source rates for anthropogenic organic aerosols may be as large as the source rates for anthropogenic sulfate aerosols, suggesting a similar magnitude of direct forcing of climate. The role of BC in decreasing the amount of reflected solar radiation by OC and sulfates is discussed. The total estimated forcing depends on the source estimates for organic and black carbon aerosols which are highly uncertain. The role of organic aerosols acting as cloud condensation nuclei (CCN) is also described.

  12. An investigation of aerosol optical properties: Atmospheric implications and influences

    Science.gov (United States)

    Penaloza-Murillo, Marcos A.

    An experimental, observational, and theoretical investigation of aerosol optical properties has been made in this work to study their implications and influences on the atmosphere. In the laboratory the scientific and instrumental methodology consisted of three parts, namely, aerosol generation, optical and mass concentration measurements, and computational calculations. In particular the optical properties of ammonium sulfate and caffeine aerosol were derived from measurements made with a transmissometer cell-reciprocal- integrating nephelometer (TCRIN), equipped with a laser beam at 632.8 nm, and by applying a Mie theory computer code The aerosol generators, optical equipment and calibration procedures were reviewed. The aerosol shape and size distribution were studied by means of scanning electron microscopy and the Gumprecht- Sliepcevich/Lipofsky-Green extinction-sedimentation method. In particular the spherical and cylindrical shape were considered. During this investigation, an alternative method for obtaining the optical properties of monodisperse spherical non-absorbing aerosol using a cell-transmissometer, which is based on a linearisation of the Lambert-Beer law, was found. In addition, adapting the TCRIN to electrooptical aerosol studies, the optical properties of a circular-cylindrical aerosol of caffeine were undertaken under the condition of random orientation in relation with the laser beam, and perpendicular orientation to it. A theoretical study was conducted to assess the sensitivity of aerosol to a change of shape under different polarisation modes. The aerosol optical properties, obtained previously in the laboratory, were then used to simulate the direct radiative forcing. The calculations and results were obtained by applying a one- dimensional energy-balance box model. The influence of atmospheric aerosol on the sky brightness due to a total solar eclipse was studied using the photometric and meteorological observations made during the

  13. Pathways, Impacts, and Policies on Severe Aerosol Injections into the Atmosphere: 2011 Severe Atmospheric Aerosols Events Conference

    KAUST Repository

    Weil, Martin

    2012-09-01

    The 2011 severe atmospheric events conference, held on August 11-12, 2011, Hamburg, Germany, discussed climatic and environmental changes as a result of various kinds of huge injections of aerosols into the atmosphere and the possible consequences for the world population. Various sessions of the conference dealt with different aspects of large aerosol injections and severe atmospheric aerosol events along the geologic time scale. A presentation about radiative heating of aerosols as a self-lifting mechanism in the Australian forest fires discussed the question of how the impact of tropical volcanic eruptions depends on the eruption season. H.-F. Graf showed that cloud-resolving plume models are more suitable to predict the volcanic plume height and dispersion than one-dimensional models. G. Stenchikov pointed out that the absorbing smoke plumes in the upper troposphere can be partially mixed into the lower stratosphere because of the solar heating and lofting effect.

  14. Secondary aerosol formation from atmospheric reactions of aliphatic amines

    Directory of Open Access Journals (Sweden)

    S. M. Murphy

    2007-01-01

    Full Text Available Although aliphatic amines have been detected in both urban and rural atmospheric aerosols, little is known about the chemistry leading to particle formation or the potential aerosol yields from reactions of gas-phase amines. We present here the first systematic study of aerosol formation from the atmospheric reactions of amines. Based on laboratory chamber experiments and theoretical calculations, we evaluate aerosol formation from reaction of OH, ozone, and nitric acid with trimethylamine, methylamine, triethylamine, diethylamine, ethylamine, and ethanolamine. Entropies of formation for alkylammonium nitrate salts are estimated by molecular dynamics calculations enabling us to estimate equilibrium constants for the reactions of amines with nitric acid. Though subject to significant uncertainty, the calculated dissociation equilibrium constant for diethylammonium nitrate is found to be sufficiently small to allow for its atmospheric formation, even in the presence of ammonia which competes for available nitric acid. Experimental chamber studies indicate that the dissociation equilibrium constant for triethylammonium nitrate is of the same order of magnitude as that for ammonium nitrate. All amines studied form aerosol when photooxidized in the presence of NOx with the majority of the aerosol mass present at the peak of aerosol growth consisting of aminium (R3NH+ nitrate salts, which repartition back to the gas phase as the parent amine is consumed. Only the two tertiary amines studied, trimethylamine and triethylamine, are found to form significant non-salt organic aerosol when oxidized by OH or ozone; calculated organic mass yields for the experiments conducted are similar for ozonolysis (15% and 5% respectively and photooxidation (23% and 8% respectively. The non-salt organic aerosol formed appears to be more stable than the nitrate salts and does not quickly repartition back to the gas phase.

  15. Atmospheric DMS and Biogenic Sulfur aerosol measurements in the Arctic

    Science.gov (United States)

    Ghahremaninezhadgharelar, R.; Norman, A. L.; Wentworth, G.; Burkart, J.; Leaitch, W. R.; Abbatt, J.; Sharma, S.; Desiree, T. S.

    2014-12-01

    Dimethyl Sulfide (DMS) and its oxidation products were measured on the board of the Canadian Coast Guard Ship (CCGS) Amundsen and above melt ponds in the Arctic during July 2014 in the context of the NETCARE study which seeks to understand the effect of DMS and its oxidation products with respect to aerosol nucleation, as well as its effect on cloud and precipitation properties. The objective of this study is to quantify the role of DMS in aerosol growth and activation in the Arctic atmosphere. Atmospheric DMS samples were collected from different altitudes, from 200 to 9500 feet, aboard the POLAR6 aircraft expedition to determine variations in the DMS concentration and a comparison was made to shipboard DMS measurements and its effects on aerosol size fractions. The chemical and isotopic composition of sulfate aerosol size fractions was studied. Sulfur isotope ratios (34S/32S) offer a way to determine the oceanic DMS contribution to aerosol growth. The results are expected to address the contribution of anthropogenic as well as biogenic sources of aerosols to the growth of the different aerosol size fractions. In addition, aerosol sulfate concentrations were measured at the same time within precipitation and fogs to compare with the characteristics of aerosols in each size fraction with the characteristics of the sulfate in each medium. This measurement is expected to explain the contribution of DMS oxidation in aerosol activation in the Arctic summer. Preliminary results from the measurement campaign for DMS and its oxidation products in air, fog and precipitation will be presented.

  16. Stratospheric benzene and hydrocarbon aerosols observed in Saturn's upper atmosphere

    Science.gov (United States)

    Guerlet, S.; Koskinen, T.

    2017-09-01

    We review recent observations of benzene and hydrocarbon aerosols in Saturn's middle and upper atmosphere by Cassini/CIRS and Cassini/UVIS. These results support the link between the precipitation of energetic electrons (ion chemistry) and the production of benzene and aerosols in Saturn's polar regions, and that solar-driven ion chemistry could also play a significant role in producing benzene at low and mid-latitudes. We also evaluate the radiative impact of the haze on Saturn's stratospheric temperatures.

  17. Volatile properties of atmospheric aerosols during nucleation events ...

    Indian Academy of Sciences (India)

    Continuous measurements of aerosol size distributions in the mid-point diameter range 20.5–500 nm were made from October 2005 to March 2006 at Pune (18° 32′N, 73° 51′E), India using Scanning Mobility Particle Sizer (SMPS). Volatilities of atmospheric aerosols were also measured at 40°, 125°, 175°, 300° and ...

  18. Elemental analysis of atmospheric aerosols in Gaborone

    African Journals Online (AJOL)

    ELO

    Aerosols are mixture of solid and liquid particles and have considerable variation in terms of their chemical composition and size. In this ... The elemental analysis was done by environmental scanning electron microscope .... the various conditions in order to identify similarities and characteristic differences in their shapes.

  19. New satellite project Aerosol-UA: Remote sensing of aerosols in the terrestrial atmosphere

    Science.gov (United States)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Mishchenko, M.; Rosenbush, V.; Ivanov, Yu.; Makarov, A.; Bovchaliuk, A.; Danylevsky, V.; Sosonkin, M.; Moskalov, S.; Bovchaliuk, V.; Lukenyuk, A.; Shymkiv, A.; Udodov, E.

    2016-06-01

    We discuss the development of the Ukrainian space project Aerosol-UA which has the following three main objectives: (1) to monitor the spatial distribution of key characteristics of terrestrial tropospheric and stratospheric aerosols; (2) to provide a comprehensive observational database enabling accurate quantitative estimates of the aerosol contribution to the energy budget of the climate system; and (3) quantify the contribution of anthropogenic aerosols to climate and ecological processes. The remote sensing concept of the project is based on precise orbital measurements of the intensity and polarization of sunlight scattered by the atmosphere and the surface with a scanning polarimeter accompanied by a wide-angle multispectral imager-polarimeter. Preparations have already been made for the development of the instrument suite for the Aerosol-UA project, in particular, of the multi-channel scanning polarimeter (ScanPol) designed for remote sensing studies of the global distribution of aerosol and cloud properties (such as particle size, morphology, and composition) in the terrestrial atmosphere by polarimetric and spectrophotometric measurements of the scattered sunlight in a wide range of wavelengths and viewing directions from which a scene location is observed. ScanPol is accompanied by multispectral wide-angle imager-polarimeter (MSIP) that serves to collect information on cloud conditions and Earth's surface image. Various components of the polarimeter ScanPol have been prototyped, including the opto-mechanical and electronic assemblies and the scanning mirror controller. Preliminary synthetic data simulations for the retrieval of aerosol parameters over land surfaces have been performed using the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm. Methods for the validation of satellite data using ground-based observations of aerosol properties are also discussed. We assume that designing, building, and launching into orbit a multi

  20. Formation of nitrogenated organic aerosols in the Titan upper atmosphere

    Science.gov (United States)

    Imanaka, Hiroshi; Smith, Mark A.

    2010-01-01

    Many aspects of the nitrogen fixation process by photochemistry in the Titan atmosphere are not fully understood. The recent Cassini mission revealed organic aerosol formation in the upper atmosphere of Titan. It is not clear, however, how much and by what mechanism nitrogen is incorporated in Titan’s organic aerosols. Using tunable synchrotron radiation at the Advanced Light Source, we demonstrate the first evidence of nitrogenated organic aerosol production by extreme ultraviolet–vacuum ultraviolet irradiation of a N2/CH4 gas mixture. The ultrahigh-mass-resolution study with laser desorption ionization-Fourier transform-ion cyclotron resonance mass spectrometry of N2/CH4 photolytic solid products at 60 and 82.5 nm indicates the predominance of highly nitrogenated compounds. The distinct nitrogen incorporations at the elemental abundances of H2C2N and HCN, respectively, are suggestive of important roles of H2C2N/HCCN and HCN/CN in their formation. The efficient formation of unsaturated hydrocarbons is observed in the gas phase without abundant nitrogenated neutrals at 60 nm, and this is confirmed by separately using 13C and 15N isotopically labeled initial gas mixtures. These observations strongly suggest a heterogeneous incorporation mechanism via short lived nitrogenated reactive species, such as HCCN radical, for nitrogenated organic aerosol formation, and imply that substantial amounts of nitrogen is fixed as organic macromolecular aerosols in Titan’s atmosphere. PMID:20616074

  1. Aerosol scattering of ultraviolet sunlight in the tropical maritime atmosphere

    Science.gov (United States)

    Ghazi, A.; Krueger, A. J.; Fraser, R. S.

    1973-01-01

    The effects of atmospheric aerosol scattering on the vertical profile of solar ultraviolet radiation are investigated. Measurements of diffuse and total ultraviolet radiation were made using a rocketborne optical sonde in the marine atmosphere of Antigua. During observations, the sun was at zenith. Vertical profiles of directly transmitted solar radiation were calculated by subtraction of the diffuse component from the total radiance. Using these values of direct downward solar UV-flux, the optical thickness of the atmosphere was derived as a function of altitude. Absorption by ozone was also considered. In the troposphere the values of observed optical thickness were in general equal to or lower than those expected theoretically from Rayleigh scattering alone. The measured radiation profiles were compared with those computed for a multiple scattering model atmosphere. Some computations regarding the interaction of UV-sunlight with maritime aerosols are presented.

  2. Chemical composition of atmospheric aerosols resolved via positive matrix factorization

    Science.gov (United States)

    Äijälä, Mikko; Junninen, Heikki; Heikkinen, Liine; Petäjä, Tuukka; Kulmala, Markku; Worsnop, Douglas; Ehn, Mikael

    2017-04-01

    Atmospheric particulate matter is a complex mixture of various chemical species such as organic compounds, sulfates, nitrates, ammonia, chlorides, black carbon and sea salt. As aerosol chemical composition strongly influences aerosol climate effects (via cloud condensation nucleus activation, hygroscopic properties, aerosol optics, volatility and condensation) as well as health effects (toxicity, carcinogenicity, particle morphology), detailed understanding of atmospheric fine particle composition is widely beneficial for understanding these interactions. Unfortunately the comprehensive, detailed measurement of aerosol chemistry remains difficult due to the wide range of compounds present in the atmosphere as well as for the miniscule mass of the particles themselves compared to their carrier gas. Aerosol mass spectrometer (AMS; Canagaratna et al., 2007) is an instrument often used for characterization of non-refractive aerosol types: the near-universal vaporization and ionisation technique allows for measurement of most atmospheric-relevant compounds (with the notable exception of refractory matter such as sea salt, black carbon, metals and crustal matter). The downside of the hard ionisation applied is extensive fragmentation of sample molecules. However, the apparent loss of information in fragmentation can be partly offset by applying advanced statistical methods to extract information from the fragmentation patterns. In aerosol mass spectrometry statistical analysis methods, such as positive matrix factorization (PMF; Paatero, 1999) are usually applied for aerosol organic component only, to keep the number of factors to be resolved manageable, to retain the inorganic components for solution validation via correlation analysis, and to avoid inorganic species dominating the factor model. However, this practice smears out the interactions between organic and inorganic chemical components, and hinders the understanding of the connections between primary and

  3. Accelerator-based chemical and elemental analysis of atmospheric aerosols

    Science.gov (United States)

    Mentes, Besim

    Aerosol particles have always been present in the atmosphere, arising from natural sources. But it was not until recently when emissions from anthropogenic (man made) sources began to dominate, that atmospheric aerosols came into focus and the aerosol science in the environmental perspective started to grow. These sources emit or produce particles with different elemental and chemical compositions, as well as different sizes of the individual aerosols. The effects of increased pollution of the atmosphere are many, and have different time scales. One of the effects known today is acid rain, which causes problems for vegetation. Pollution is also a direct human health risk, in many cities where traffic driven by combustion engines is forbidden at certain times when the meteorological conditions are unfavourable. Aerosols play an important role in the climate, and may have both direct and indirect effect which cause cooling of the planet surface, in contrast to the so-called greenhouse gases. During this work a technique for chemical and elemental analysis of atmospheric aerosols and an elemental analysis methodology for upper tropospheric aerosols have been developed. The elemental analysis is performed by the ion beam analysis (IBA) techniques, PIXE (elements heavier than Al). PESA (C, N and O), cPESA (H) and pNRA (Mg and Na). The chemical speciation of atmospheric aerosols is obtained by ion beam thermography (IBT). During thermography the sample temperature is stepwise increased and the IBA techniques are used to continuously monitor the elemental concentration. A thermogram is obtained for each element. The vaporisation of the compounds in the sample appears as a concentration decrease in the thermograms at characteristic vaporisation temperatures (CVTs). Different aspects of IBT have been examined in Paper I to IV. The features of IBT are: almost total elemental speciation of the aerosol mass, chemical speciation of the inorganic compounds, carbon content

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

    Science.gov (United States)

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

    2014-05-01

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

  5. Enhancement of atmospheric radiation by an aerosol layer

    Science.gov (United States)

    Michelangeli, Diane V.; Yung, Yuk L.; Shia, Run-Lie; Eluszkiewicz, Janusz; Allen, Mark; Crisp, David

    1992-01-01

    The presence of a stratospheric haze layer may produce increases in both the actinic flux and the irradiance below this layer. Such haze layers result from the injection of aerosol-forming material into the stratosphere by volcanic eruptions. Simple heuristic arguments show that the increase in flux below the haze layer, relative to a clear sky case, is a consequence of 'photon trapping'. The magnitude of these flux perturbations, as a function of aerosol properties and illumination conditions, is explored with a new radiative transfer model that can accurately compute fluxes in an inhomogeneous atmosphere with nonconservative scatterers having arbitrary phase function. One calculated consequence of the El Chichon volcanic eruption is an increase in the midday surface actinic flux at 20 deg N latitude, summer, by as much as 45 percent at 2900 A. This increase in flux in the UV-B wavelength range was caused entirely by aerosol scattering, without any reduction in the overhead ozone column.

  6. Organic compounds in atmospheric aerosols from a Finnish coniferous forest

    Energy Technology Data Exchange (ETDEWEB)

    Anttila, P.; Rissanen, T.; Shimmo, M.; Kallio, M.; Hyoetylaeinen, T.; Riekkola, M.L. [Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki (Finland); Kulmala, M. [Department of Physical Sciences, University of Helsinki (Finland)

    2005-07-01

    Atmospheric aerosol particles were collected with a high-volume sampler in a Finnish coniferous forest during the field campaign Quantification of Aerosol Nucleation in the European Boundary Layer (QUEST) in March-April 2003. Four chromatographic techniques were applied to characterise the organic composition of the samples, and to study variations in the concentrations of identified compounds. Among the nearly 160 organic compounds identified were n-alkanes, nalkanals, n-alkan-2-ones, n- alkanols, n-alkanoic acids, n-alkenoic acids, dicarboxylic acids, polyaromatic hydrocarbons, hopanes, streranes, terpenes and terpenoids. The observed variations in the concentrations of certain compounds were mostly explained by ambient temperature. Comparison of days when atmospheric new particle formation took place with days when the formation did not occur, however, revealed higher concentrations of long-chain n- alkanes (> C{sub 22}) and < C{sub 18} n-alkanoic acids on the particle formation days. (orig.)

  7. Unintended consequences of atmospheric injection of sulphate aerosols.

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Patrick Vane; Kobos, Peter Holmes; Goldstein, Barry

    2010-10-01

    Most climate scientists believe that climate geoengineering is best considered as a potential complement to the mitigation of CO{sub 2} emissions, rather than as an alternative to it. Strong mitigation could achieve the equivalent of up to -4Wm{sup -2} radiative forcing on the century timescale, relative to a worst case scenario for rising CO{sub 2}. However, to tackle the remaining 3Wm{sup -2}, which are likely even in a best case scenario of strongly mitigated CO{sub 2} releases, a number of geoengineering options show promise. Injecting stratospheric aerosols is one of the least expensive and, potentially, most effective approaches and for that reason an examination of the possible unintended consequences of the implementation of atmospheric injections of sulphate aerosols was made. Chief among these are: reductions in rainfall, slowing of atmospheric ozone rebound, and differential changes in weather patterns. At the same time, there will be an increase in plant productivity. Lastly, because atmospheric sulphate injection would not mitigate ocean acidification, another side effect of fossil fuel burning, it would provide only a partial solution. Future research should aim at ameliorating the possible negative unintended consequences of atmospheric injections of sulphate injection. This might include modeling the optimum rate and particle type and size of aerosol injection, as well as the latitudinal, longitudinal and altitude of injection sites, to balance radiative forcing to decrease negative regional impacts. Similarly, future research might include modeling the optimum rate of decrease and location of injection sites to be closed to reduce or slow rapid warming upon aerosol injection cessation. A fruitful area for future research might be system modeling to enhance the possible positive increases in agricultural productivity. All such modeling must be supported by data collection and laboratory and field testing to enable iterative modeling to increase the

  8. Atmospheric Optical Properties and Spectral Analysis of Desert Aerosols

    Science.gov (United States)

    Yvgeni, D.; Karnieli, A.; Kaufman, Y. J.; Andreae, M. O.; Holben, B. N.; Maenhaut, W.

    2002-05-01

    Scientific background Aerosols can interact directly with solar and terrestrial radiation by scattering as well as absorption. In addition, they can indirectly alter the planetary albedo by modifying the properties of clouds. Objectives Investigations have been devoted to two main areas: (1) Aerosol climatology situation in the Negev desert, investigations of physical and chemical characteristics of aerosols, and study of the local and long-range transport trajectory of polluted air masses over the Negev desert; and (2) An estimation of the optical properties throughout the atmospheric column by surface measurements via performance of spectral and statistical analysis of the data received from two measurement systems. Results and conclusions Analyzed data from the Sede Boker site, in the Negev Desert of Israel, shows an increase in aerosol optical depth during the summer seasons and a decrease during winter. One of the possible reasons for this characteristic is an increase of the precipitable water (reaches 3.0-3.5 cm) due to a constant wind stream from the Mediterranean Sea in same time. The highest probability distribution of the aerosol optical depth is in the range of 0.15-0.20; and of the Angstrom parameter is in range of 0.83 - 1.07. During dust storm events, the scattering coefficient range at 670 nm and 440 nm wavelengths were inverted. It was discovered that the dust particles in this case had non-spherical character. Comparison between optical depth, measured through all atmospheric column, and scattering coefficient from surface measurements provides correlation coefficient (r) equal to 0.64. The Angstrom parameter, calculated via optical depth and via scattering coefficient, provides a correlation coefficient of 0.66. Thus we can obtain an estimate of the influence of the surface aerosol situation on column optical properties. The combined analysis of dust cloud altitude and optical depth as a function of the time indicates long-term transport and

  9. Mode resolved density of atmospheric aerosol particles

    Directory of Open Access Journals (Sweden)

    P. Aalto

    2008-09-01

    Full Text Available In this study, we investigate the mode resolved density of ultrafine atmospheric particles measured in boreal forest environment. The method used here enables us to find the distinct density information for each mode in atmospheric fine particle population: the density values for nucleation, Aitken, and accumulation mode particles are presented. The experimental data was gained during 2 May 2005–19 May 2005 at the boreal forest measurement station "SMEAR II" in Hyytiälä, Southern Finland. The density values for accumulation mode varied from 1.1 to 2 g/cm3 (average 1.5 g/cm3 and for Aitken mode from 0.4 to 2 g/cm3 (average 0.97 g/cm3. As an overall trend during the two weeks campaign, the density value of Aitken mode was seen to gradually increase. With the present method, the time dependent behaviour of the particle density can be investigated in the time scale of 10 min. This allows us to follow the density evolution of the nucleation mode particles during the particle growth process following the nucleation burst. The density of nucleation mode particles decreased during the growth process. The density values for 15 nm particles were 1.2–1.5 g/cm3 and for grown 30 nm particles 0.5–1 g/cm3. These values are consistent with the present knowledge that the condensing species are semi-volatile organics, emitted from the boreal forest.

  10. Microbiology and atmospheric processes: chemical interactions of primary biological aerosols

    Directory of Open Access Journals (Sweden)

    L. Deguillaume

    2008-07-01

    Full Text Available This paper discusses the influence of primary biological aerosols (PBA on atmospheric chemistry and vice versa through microbiological and chemical properties and processes. Several studies have shown that PBA represent a significant fraction of air particulate matter and hence affect the microstructure and water uptake of aerosol particles. Moreover, airborne micro-organisms, namely fungal spores and bacteria, can transform chemical constituents of the atmosphere by metabolic activity. Recent studies have emphasized the viability of bacteria and metabolic degradation of organic substances in cloud water. On the other hand, the viability and metabolic activity of airborne micro-organisms depend strongly on physical and chemical atmospheric parameters such as temperature, pressure, radiation, pH value and nutrient concentrations. In spite of recent advances, however, our knowledge of the microbiological and chemical interactions of PBA in the atmosphere is rather limited. Further targeted investigations combining laboratory experiments, field measurements, and modelling studies will be required to characterize the chemical feedbacks, microbiological activities at the air/snow/water interface supplied to the atmosphere.

  11. Chemistry of Atmospheric Aerosols at Pacifichem 2015 Congress

    Energy Technology Data Exchange (ETDEWEB)

    Nizkorodov, Sergey [Univ. of California, Irvine, CA (United States)

    2016-12-28

    This grant was used to provide participant support for a symposium entitled “Chemistry of Atmospheric Aerosols” at the 2015 International Chemical Congress of Pacific Basin Societies (Pacifichem) that took place in Honolulu, Hawaii, USA, on December 15-20, 2015. The objective was to help attract both distinguished scientists as well as more junior researchers, including graduate students, to this international symposium by reducing the financial barrier for its attendance. It was the second time a symposium devoted to Atmospheric Aerosols was part of the Pacifichem program. This symposium provided a unique opportunity for the scientists from different countries to gather in one place and discuss the cutting edge advances in the cross-disciplinary areas of aerosol research. To achieve the highest possible impact, the PI and the symposium co-organizers actively advertised the symposium by e-mail and by announcements at other conferences. A number of people responded, and the end result was a very busy program with about 100 oral and poster presentation described in the attached PDF file. Presentations by invited speakers occupied approximately 30% of time in each of the sessions. In addition to the invited speakers, each session also had contributed presentations, including those by graduate students and postdoctoral researchers. This symposium gathered established aerosol chemists from a number of countries including United States, Canada, China, Japan, Korea, Australia, Brazil, Hongkong, Switzerland, France, and Germany. There were plenty of time for the attendees to discuss new ideas and potential collaborations both during the oral sessions and at the poster sessions of the symposium. The symposium was very beneficial to graduate student researchers, postdoctoral fellows, and junior researchers whose prior exposure to international aerosol chemistry science had been limited. The symposium provided junior researchers with a much broader perspective of aerosol

  12. Application of the variability-size relationship to atmospheric aerosol studies: estimating aerosol lifetimes and ages

    Directory of Open Access Journals (Sweden)

    J. Williams

    2002-01-01

    Full Text Available Aerosol variability is examined as function of particle size for data collected over the Northern Indian Ocean in February 1999 as part of the INDOEX experiment. It was found that for particles believed to be of terrestrial or oceanic origin, the variability correlated with the average number concentration. For particles that are thought to be formed and grow in the atmosphere through coagulation and condensation an anticorrelation was observed, the minimum in variability coinciding with the maximum in the number concentration. Three altitude ranges were examined (0--1, 4--8 and 8--13 km and the minimum in variability was found to occur at lower particle sizes in the free troposphere (0.065 mm than in the boundary layer (0.165 mm. The observed variability has been compared to that generated by a numerical model in order to determine the relative importance of the physical processes. Modelled variability of 0.02 mm particles caused by nucleation was not observed in the measurements. A previously derived empirical relationship for aerosol residence time was compared with the measured variability as a function of bin size. The aerosol variability / residence time relationship was characterised by a coefficient (b at all altitudes and for both correlating and anticorrelating regimes. By combining the derived coefficient with the model predicted lifetime for 0.020 mm particles we estimated residence times and ages as a function of particle size and altitude. General agreement was found with previous estimates of aerosol residence time. In the upper atmosphere aerosols of 0.065 mm in size have residence times of approximately 1 month and can be transported on a hemispheric scale. The same size aerosol has a lifetime one order of magnitude less in the boundary layer and therefore will not be transported far from the source regions.

  13. Remote sensing of atmospheric aerosols with the SPEX spectropolarimeter

    Science.gov (United States)

    van Harten, G.; Rietjens, J.; Smit, M.; Snik, F.; Keller, C. U.; di Noia, A.; Hasekamp, O.; Vonk, J.; Volten, H.

    2013-12-01

    Characterizing atmospheric aerosols is key to understanding their influence on climate through their direct and indirect radiative forcing. This requires long-term global coverage, at high spatial (~km) and temporal (~days) resolution, which can only be provided by satellite remote sensing. Aerosol load and properties such as particle size, shape and chemical composition can be derived from multi-wavelength radiance and polarization measurements of sunlight that is scattered by the Earth's atmosphere at different angles. The required polarimetric accuracy of ~10^(-3) is very challenging, particularly since the instrument is located on a rapidly moving platform. Our Spectropolarimeter for Planetary EXploration (SPEX) is based on a novel, snapshot spectral modulator, with the intrinsic ability to measure polarization at high accuracy. It exhibits minimal instrumental polarization and is completely solid-state and passive. An athermal set of birefringent crystals in front of an analyzer encodes the incoming linear polarization into a sinusoidal modulation in the intensity spectrum. Moreover, a dual beam implementation yields redundancy that allows for a mutual correction in both the spectrally and spatially modulated data to increase the measurement accuracy. A partially polarized calibration stimulus has been developed, consisting of a carefully depolarized source followed by tilted glass plates to induce polarization in a controlled way. Preliminary calibration measurements show an accuracy of SPEX of well below 10^(-3), with a sensitivity limit of 2*10^(-4). We demonstrate the potential of the SPEX concept by presenting retrievals of aerosol properties based on clear sky measurements using a prototype satellite instrument and a dedicated ground-based SPEX. The retrieval algorithm, originally designed for POLDER data, performs iterative fitting of aerosol properties and surface albedo, where the initial guess is provided by a look-up table. The retrieved aerosol

  14. Chemistry in the clouds: the role of aerosols in atmospheric chemistry.

    Science.gov (United States)

    Reid, Jonathan P; Sayer, Robert M

    2002-01-01

    Ever since the discovery of the ozone hole over the Antarctic and the recognition of the damaging effects of acid rain, the role of atmospheric aerosol particles in determining the chemical balance of the atmosphere has received much attention. Aerosol particles produced in combustion can also have a deleterious effect on human health. In this article we review the chemistry that can occur on aerosol particles, particularly on aqueous based aerosols in the troposphere. The sources, transformation and loss mechanisms of atmospheric aerosol will be discussed. In particular, we will focus on the role of chemical transformation on aerosol particles in promoting reactions that would otherwise be too slow in the homogeneous atmospheric gas phase. Heterogeneous reaction mechanisms of some key chemical reactions will be described. Recent observations of a high organic content of tropospheric aerosol particles will be described and a model of organic coated aerosols will be reviewed.

  15. Atmospheric aerosol over Vermont: chemical composition and sources

    Energy Technology Data Exchange (ETDEWEB)

    Polissar, A.V.; Hopke, P.K. [Clarkson University, Potsdam, NY (United States). Dept. of Chemical Engineering

    2001-12-01

    Aerosol chemical composition data for PM{sub 2.5} samples collected during the period from 1988 to 1995 at Underhill, VT were analyzed. The six sources representing wood burning, coal and oil combustion, coal combustion emissions plus photochemical sulfate production, metal production plus municipal wastes incineration, and emissions from motor vehicles were identified. Emissions from smelting of nonferrous metal ores, arsenic smelting, and soil particles and particles with high concentrations of Na were also identified by PMF. Potential source contribution function (PSCF) analysis for the black carbon factor shows high probabilities in the area surrounding the sampling wood combustion in northern New England and southwestern Quebec. Similar large potential source areas in the midwestern United States were identified for the coal combustion factors. The oil combustion factor was associated with the east coast of the United States. canadian Ni smelters are the main sources for the As factor, although there is some contribution from coal-fired power plants to the south and west of Underhill, VT. It is concluded that the combination of the two receptor modeling methods, PMF and PSCF, provides an effective way in identifying atmospheric aerosol sources and their likely locations. Emissions from different anthropogenic activities as well as secondary aerosol production are the main sources of aerosol measured in Vermont. Fuel combustion, local wood smoke, municipal waste incineration and the secondary sulfate production collectively accounted for about 87% of the fine mass concentrations measured in Vermont. 29 refs., 18 figs., 2 tabs.

  16. Near-infrared laser desorption/ionization aerosol mass spectrometry for measuring organic aerosol at atmospherically relevant aerosol mass loadings

    Directory of Open Access Journals (Sweden)

    S. Geddes

    2010-08-01

    Full Text Available A new method, near-infrared laser desorption/ionization aerosol mass spectrometry (NIR-LDI-AMS, is described for the real time analysis of organic aerosols at atmospherically relevant total mass loadings. Particles are sampled with an aerodynamic lens onto an aluminum probe. A moderate energy NIR laser pulse at 1064 nm is directed onto the probe to vaporize and ionize particle components. Delayed pulse extraction is then used to sample the ions into a reflectron time of flight mass spectrometer for chemical analysis. The soft ionization afforded by the NIR photons results in minimal fragmentation (loss of a hydrogen atom producing intact pseudo-molecular anions at [M-H]. The limit of detection measured for pure oleic acid particles (geometric mean diameter and standard deviation of 180 nm and 1.3, respectively was 140 fg (or 1.7 ng m−3 per minute sampling time. As an example of the utility of NIR-LDI-AMS to measurements of atmospheric importance, the method was applied to laboratory chamber measurements of the secondary organic aerosol formation from ozonolysis of α-pinene. High quality mass spectra were recorded with a 2-min time resolution for total aerosol mass loadings ranging from 1.5 to 8.7 μg m−3. These results demonstrate the potential of NIR-LDI-AMS to allow for more accurate measurements of the organic fraction of atmospheric particulate at realistic mass loadings. Measurements at ambient-levels of SOA mass loading are important to improve parameterizations of chamber-based SOA formation for modeling regional and global SOA fluxes and to aid in remediating the discrepancy between modeled and observed atmospheric total SOA production rates and concentrations.

  17. Thermodynamic modeling of atmospheric aerosols: 0-100% relative humidity

    Science.gov (United States)

    Dutcher, Cari S.; Ge, Xinlei; Asato, Caitlin; Wexler, Anthony S.; Clegg, Simon L.

    2013-05-01

    Accurate models of water and solute activities in aqueous atmospheric aerosols are central to predicting aerosol size, optical properties and cloud formation. A powerful method has been recently developed (Dutcher et al. JPC 2011, 2012, 2013) for representing the thermodynamic properties of multicomponent aerosols at low and intermediate levels of RH (adjustable model parameters, allowing for a unified thermodynamic treatment for a wider range of atmospheric systems. The long-range interactions due to electrostatic screening of ions in solution are included as a mole fraction based Pitzer-Debye-Hückel (PDH) term. Equations for the Gibbs free energy, solvent and solute activity, and solute concentration are derived, yielding remarkable agreement between measured and fitted solute concentration and osmotic coefficients for solutions over the entire 0 to 100% RH range. By relating the values of the energy of sorption in each hydration layer to known short-range Coulombic electrostatic relationships governed by the size and dipole moment of the solute and solvent molecules, it may be possible to reduce the number of parameters for each solute. Modified equations for mixtures that take into account the long range PDH term will also be presented; these equations include no additional parameters.

  18. Sulfuric acid aerosols in the atmospheres of the terrestrial planets

    Science.gov (United States)

    McGouldrick, Kevin; Toon, Owen B.; Grinspoon, David H.

    2011-08-01

    Clouds and hazes composed of sulfuric acid are observed to exist or postulated to have once existed on each of the terrestrial planets with atmospheres in our solar system. Venus today maintains a global cover of clouds composed of a sulfuric acid/water solution that extends in altitude from roughly 50 km to roughly 80 km. Terrestrial polar stratospheric clouds (PSCs) form on stratospheric sulfuric acid aerosols, and both PSCs and stratospheric aerosols play a critical role in the formation of the ozone hole. Stratospheric aerosols can modify the climate when they are enhanced following volcanic eruptions, and are a current focus for geoengineering studies. Rain is made more acidic by sulfuric acid originating from sulfur dioxide generated by industry on Earth. Analysis of the sulfur content of Martian rocks has led to the hypothesis that an early Martian atmosphere, rich in SO 2 and H 2O, could support a sulfur-infused hydrological cycle. Here we consider the plausibility of frozen sulfuric acid in the upper clouds of Venus, which could lead to lightning generation, with implications for observations by the European Space Agency's Venus Express and the Japan Aerospace Exploration Agency's Venus Climate Orbiter (also known as Akatsuki). We also present simulations of a sulfur-rich early Martian atmosphere. We find that about 40 cm/yr of precipitation having a pH of about 2.0 could fall in an early Martian atmosphere, assuming a surface temperature of 273 K, and SO 2 generation rates consistent with the formation of Tharsis. This modeled acid rain is a powerful sink for SO 2, quickly removing it and preventing it from having a significant greenhouse effect.

  19. Infrared Absorption by Atmospheric Aerosols in Mexico City during MILAGRO.

    Science.gov (United States)

    Kelley, K. L.; Mangu, A.; Gaffney, J. S.; Marley, N. A.

    2007-12-01

    found as colloidal materials in surface and groundwaters (4). Examples of the IR spectra obtained and variance as a function of time at the two sites will be presented. The spectra are taken in Kubelka - Munk format, which also allows the infrared absorption strengths to be evaluated as function of wavelength. The wavelength dependence of the aerosol complex refractive index (m = n + ik) in the infrared spectral region is determined by application of the Kramers Kronig function. The importance of the aerosol absorption in the infrared spectral region to radiative forcing will be discussed. 1. N.A. Marley, J.S. Gaffney, and M.M. Cunningham,Environ. Sci. Technol. 27 2864-2869 (1993). 2. N.A. Marley, J.S. Gaffney, and M.M. Cunningham, Spectroscopy 7 44-53 (1992). 3. J.S. Gaffney and N.A. Marley, Atmospheric Environment, New Directions contribution, 32, 2873-2874 (1998). 4. N.A. Marley, J.S. Gaffney, and K.A. Orlandini, Chapter 7 in Humic/Fulvic Acids and Organic Colloidal Materials in the Environment, ACS Symposium Series 651, American Chemical Society, Washington, D.C., pp. 96-107, 1996. This work was performed as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX- Mex) under the support of the Atmospheric Science Program. This research was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64328.

  20. Upper-atmosphere Aerosols: Properties and Natural Cycles

    Science.gov (United States)

    Turco, Richard P.

    1992-01-01

    The middle atmosphere is rich in its variety of particulate matter, which ranges from meteorite debris, to sulfate aerosols, to polar stratospheric ice clouds. Volcanic eruptions strongly perturb the stratospheric sulfate (Junge) layer. High-altitude 'noctilucent' ice clouds condense at the summer mesopause. The properties of these particles, including their composition, sizes, and geographical distribution, are discussed, and their global effects, including chemical, radiative, and climatic roles, are reviewed. Polar stratospheric clouds (PSCs) are composed of water and nitric acid in the form of micron-sized ice crystals. These particles catalyze reactions of chlorine compounds that 'activate' otherwise inert chlorine reservoirs, leading to severe ozone depletions in the southern polar stratosphere during austral spring. PSCs also modify the composition of the polar stratosphere through complex physiocochemical processes, including dehydration and denitrification, and the conversion of reactive nitrogen oxides into nitric acid. If water vapor and nitric acid concentrations are enhanced by high-altitude aircraft activity, the frequency, geographical range, and duration of PSCs might increase accordingly, thus enhancing the destruction of the ozone layer (which would be naturally limited in geographical extent by the same factors that confine the ozone hole to high latitudes in winter). The stratospheric sulfate aerosol layer reflects solar radiation and increases the planetary albedo, thereby cooling the surface and possibly altering the climate. Major volcanic eruptions, which increase the sulfate aerosol burden by a factor of 100 or more, may cause significant global climate anomalies. Sulfate aerosols might also be capable of activating stratospheric chlorine reservoirs on a global scale (unlike PCSs, which represent a localized polar winter phenomenon), although existing evidence suggests relatively minor perturbations in chlorine chemistry. Nevertheless, if

  1. The influence of ions on atmospheric aerosol processes

    DEFF Research Database (Denmark)

    Enghoff, Martin

    2008-01-01

    Ice Age, the Medieval Warmth, and other climate phenomena going further back in time, is that of Ion Induced Nucleation { the ability of ions to enhance the formation of aerosol particles in the atmosphere. Several nucleation events that cannot be explained with the standard theory of homogeneous......Considering the big climate changes of the recent centuries and the predictions of future changes, it becomes increasingly important to understand what mechanisms drive climate. One such mechanism, that has been held responsible for changes in cloud cover during the last 25 years, for the Little...

  2. Characterizations of atmospheric fungal aerosol in Beijing, China

    Science.gov (United States)

    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

  3. Lidar Atmospheric Sensing Experiment (LASE) Data Obtained During the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lidar Atmospheric Sensing Experiment (LASE) Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) data set was collected over the Western...

  4. Physical and optical properties of Atmospheric aerosols measured from a Coastal site

    Science.gov (United States)

    2017-06-01

    PSAP) ...........................................................................................19  3.  Passive Cavity Aerosol Spectrometer Probe...atmospheric boundary layer NASU NPS Aerosol Sampling Unit NEPH TSI Integrating 3563 Nephelometer PCASP Passive Cavity Aerosol Spectrometer Probe PSAP...liquid surfaces, such as rocks, road surfaces or machinery,” as described by Twomey (1977). Dusts, fumes, smoke , smog, and haze are all forms of land

  5. High spectral resolution lidar to measure optical scattering properties of atmospheric aerosols. I - Theory and instrumentation

    Science.gov (United States)

    Shipley, S. T.; Tracy, D. H.; Eloranta, E. W.; Roesler, F. L.; Weinman, J. A.; Trauger, J. T.; Sroga, J. T.

    1983-01-01

    A high spectral resolution lidar technique to measure optical scattering properties of atmospheric aerosols is described. Light backscattered by the atmosphere from a narrowband optically pumped oscillator-amplifier dye laser is separated into its Doppler broadened molecular and elastically scattered aerosol components by a two-channel Fabry-Perot polyetalon interferometer. Aerosol optical properties, such as the backscatter ratio, optical depth, extinction cross section, scattering cross section, and the backscatter phase function, are derived from the two-channel measurements.

  6. Multielemental composition of atmospheric aerosol in the South of West Siberia

    CERN Document Server

    Koutsenogii, K P; Smirnova, A I; Makarov, V I; Kirov, E I

    2000-01-01

    The data on the multielemental composition of atmospheric aerosols for the typical landscapes of Novosibirsk region have been obtained using SR XRF. The peculiarities of seasonal variations in the multielemental composition of atmospheric aerosols in the South of West Siberia have been analyzed.

  7. Sugars in atmospheric aerosols over the Eastern Mediterranean

    Science.gov (United States)

    Theodosi, Christina; Panagiotopoulos, Christos; Nouara, Amel; Zarmpas, Pavlos; Nicolaou, Panagiota; Violaki, Kalliopi; Kanakidou, Maria; Sempéré, Richard; Mihalopoulos, Nikolaos

    2017-04-01

    The role of biomass combustion and primary bio-particles in atmospheric PM10 aerosols in the Eastern Mediterranean over a two-year period was estimated by studying sugar tracers. Sugar concentrations ranged from 6 to 334 ng m-3, while their contributions to the organic carbon (OC) and water soluble organic carbon (WSOC) pools were 3 and 11%, respectively. Over the studied period, glucose and levoglucosan were the two most abundant sugars accounting equally about 25% of the total sugar concentration in PM10 aerosols whereas fructose, sucrose, and mannitol represented 18%, 15% and 10%, respectively. Primary saccharides (glucose, fructose, and sucrose) peaked at the beginning of spring (21, 17 and 15 ng m-3, respectively), indicating significant contributions of bioaerosols to the total organic aerosol mass. On the other hand, higher concentrations of anhydrosugars (burning biomass tracers including levoglucosan, mannosan and galactosan) were recorded in winter (19, 1.4 and 0.2 ng m-3, respectively) than in summer (9.1, 1.1 and 0.5 ng m-3, respectively). Levoglucosan was the dominant monosaccharide in winter (37% of total sugars) with less contribution in summer (19%) probably in relation with enhanced photochemical oxidation reactions by hydroxyl (ṡOH) radicals impacting anhydrosugars. We estimate that atmospheric oxidation by ṡOH decreases levoglucosan levels by 54% during summer. Biomass burning, based on levoglucosan observations, was estimated to contribute up to 13% to the annual average OC measured at Finokalia. Annual OC, WSOC, and carbohydrate dry deposition fluxes for the studied period were estimated to 414, 175, and 9 mg C m-2 y-1, respectively. Glucose and levoglucosan accounted for 34% and 2% of the total sugar fluxes. According to our estimations, atmospheric OC and WSOC inputs account for ˜0.70% of the carbon produced by annual primary production (PP) in the Cretan Sea. Considering the entire Mediterranean, dry deposition of OC could provide at

  8. Atmospheric aerosol over Vermont: chemical composition and sources.

    Science.gov (United States)

    Polissar, A V; Hopke, P K; Poirot, R L

    2001-12-01

    areas in the midwestern United States were identified for the two coal combustion factors. The midwestern United States was also identified as the source region for the Zn-Pb factor. The oil combustion factor was associated with the east coast of the United States. The results for the Pb-Mn factor suggests high probability over the nearby Montreal urban area and the areas in the midwestern United States. The windblown dust emissions from the areas to the north are significant contributors for the soil factor. Canadian Ni smelters are the main sources for the As factor, although there is some contribution from coal-fired power plants to the south and west of Underhill, VT. It is concluded that the combination of the two receptor modeling methods, PMF and PSCF, provides an effective way in identifying atmospheric aerosol sources and their likely locations. Emissions from different anthropogenic activities as well as secondary aerosol production are the main sources of aerosol measured in Vermont. Fuel combustion, local wood smoke, municipal waste incineration, and the secondary sulfate production collectively accounted for about 87% of the fine mass concentrations measured in Vermont.

  9. Easy Aerosol - Robust and non-robust circulation responses to aerosol radiative forcing in comprehensive atmosphere models

    Science.gov (United States)

    Voigt, Aiko; Bony, Sandrine; Stevens, Bjorn; Boucher, Olivier; Medeiros, Brian; Pincus, Robert; Wang, Zhili; Zhang, Kai; Lewinschal, Anna; Bellouin, Nicolas; Yang, Young-Min

    2015-04-01

    A number of recent studies illustrated the potential of aerosols to change the large-scale atmospheric circulation and precipitation patterns. It remains unclear, however, to what extent the proposed aerosol-induced changes reflect robust model behavior or are affected by uncertainties in the models' treatment of parametrized physical processes, such as those related to clouds. "Easy Aerosol", a model-intercomparison project organized within the Grand Challenge on Clouds, Circulation and Climate Sensitivity of the World Climate Research Programme, addresses this question by subjecting a suite of comprehensive atmosphere general circulation models with prescribed sea-surface temperatures (SSTs) to the same set of idealized "easy" aerosol perturbations. This contribution discusses the aerosol perturbations as well as their impact on the model's precipitation and surface winds. The aerosol perturbations are designed based on a global aerosol climatology and mimic the gravest mode of the anthropogenic aerosol. Specifically, the meridional and zonal distributions of total aerosol optical depth are approximated by a superposition of Gaussian plumes; the vertical distribution is taken as constant within the lowest 1250m of the atmosphere followed by an exponential decay with height above. The aerosol both scatters and absorbs shortwave radiation, but in order to focus on direct radiative effects aerosol-cloud interactions are omitted. Each model contributes seven simulations. A clean control case with no aerosol-radiative effects at all is compared to six perturbed simulations with differing aerosol loading, zonal aerosol distributions, and SSTs. To estimate the role of natural variability, one of the models, MPI-ESM, contributes a 5-member ensemble for each simulation. If the observed SSTs from years 1979-2005 are prescribed, the aerosol leads to a local depression of precipitation at the Northern Hemisphere center of the aerosol and a northward shift of the

  10. Small molecules as tracers in atmospheric secondary organic aerosol

    Science.gov (United States)

    Yu, Ge

    Secondary organic aerosol (SOA), formed from in-air oxidation of volatile organic compounds, greatly affects human health and climate. Although substantial research has been devoted to SOA formation and evolution, the modeled and lab-generated SOA are still low in mass and degree of oxidation compared to ambient measurements. In order to compensate for these discrepancies, the aqueous processing pathway has been brought to attention. The atmospheric waters serve as aqueous reaction media for dissolved organics to undergo further oxidation, oligomerization, or other functionalization reactions, which decreases the vapor pressure while increasing the oxidation state of carbon atoms. Field evidence for aqueous processing requires the identification of tracer products such as organosulfates. We synthesized the standards for two organosulfates, glycolic acid sulfate and lactic acid sulfate, in order to measure their aerosol-state concentration from five distinct locations via filter samples. The water-extracted filter samples were analyzed by LC-MS. Lactic acid sulfate and glycolic acid sulfate were detected in urban locations in the United States, Mexico City, and Pakistan with varied concentrations, indicating their potential as tracers. We studied the aqueous processing reaction between glyoxal and nitrogen-containing species such as ammonium and amines exclusively by NMR spectrometry. The reaction products formic acid and several imidazoles along with the quantified kinetics were reported. The brown carbon generated from these reactions were quantified optically by UV-Vis spectroscopy. The organic-phase reaction between oxygen molecule and alkenes photosensitized by alpha-dicarbonyls were studied in the same manner. We observed the fast kinetics transferring alkenes to epoxides under simulated sunlight. Statistical estimations indicate a very effective conversion of aerosol-phase alkenes to epoxides, potentially forming organosulfates in a deliquescence event and

  11. MATRIX (Multiconfiguration Aerosol TRacker of mIXing state: an aerosol microphysical module for global atmospheric models

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2008-10-01

    Full Text Available A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS climate model (ModelE are described. This module, which is based on the quadrature method of moments (QMOM, represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol population, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble aerosol populations.

    A detailed model description and results of box-model simulations of various aerosol population configurations are presented. The box model experiments demonstrate the dependence of cloud activating aerosol number concentration on the aerosol population configuration; comparisons to sectional models are quite favorable. MATRIX is incorporated into the GISS climate model and simulations are carried out primarily to assess its performance/efficiency for global-scale atmospheric model application. Simulation results were compared with aircraft and station measurements of aerosol mass and number concentration and particle size to assess the ability of the new method to yield data suitable for such comparison. The model accurately captures the observed size distributions in the Aitken and accumulation modes up to particle diameter 1 μm, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment

  12. Volatility measurement of atmospheric submicron aerosols in an urban atmosphere in southern China

    Directory of Open Access Journals (Sweden)

    L.-M. Cao

    2018-02-01

    Full Text Available Aerosol pollution has been a very serious environmental problem in China for many years. The volatility of aerosols can affect the distribution of compounds in the gas and aerosol phases, the atmospheric fates of the corresponding components, and the measurement of the concentration of aerosols. Compared to the characterization of chemical composition, few studies have focused on the volatility of aerosols in China. In this study, a thermodenuder aerosol mass spectrometer (TD-AMS system was deployed to study the volatility of non-refractory submicron particulate matter (PM1 species during winter in Shenzhen. To our knowledge, this paper is the first report of the volatilities of aerosol chemical components based on a TD-AMS system in China. The average PM1 mass concentration during the experiment was 42.7±20.1 µg m−3, with organic aerosol (OA being the most abundant component (43.2 % of the total mass. The volatility of chemical species measured by the AMS varied, with nitrate showing the highest volatility, with a mass fraction remaining (MFR of 0.57 at 50 °C. Organics showed semi-volatile characteristics (the MFR was 0.88 at 50 °C, and the volatility had a relatively linear correlation with the TD temperature (from the ambient temperature to 200 °C, with an evaporation rate of 0.45 % °C−1. Five subtypes of OA were resolved from total OA using positive matrix factorization (PMF for data obtained under both ambient temperature and high temperatures through the TD, including a hydrocarbon-like OA (HOA, accounting for 13.5 %, a cooking OA (COA, 20.6 %, a biomass-burning OA (BBOA, 8.9 %, and two oxygenated OAs (OOAs: a less-oxidized OOA (LO-OOA, 39.1 % and a more-oxidized OOA (MO-OOA, 17.9 %. Different OA factors presented different volatilities, and the volatility sequence of the OA factors at 50 °C was HOA (MFR of 0.56  >  LO-OOA (0.70  >  COA (0.85  ≈  BBOA (0.87

  13. Sentinel-5 Precursor: Global Monitoring of Atmospheric Trace Gases & Aerosols

    Science.gov (United States)

    Nett, Herbert; McMullan, Kevin; Ingmann, Paul

    2013-04-01

    ESA's Sentinel 5 Precursor (S5P) Mission will form part of the Space Component under the Global Monitoring for Environment and Security (GMES) initiative. It represents a preparatory project for the GMES atmospheric missions that comprise both a geo-stationary (Sentinel-4 / part of MTG-S payload) and a polar orbiting (Sentinel-5 / MetOp Second Generation) component. In view of the planned launch date of around 2020 for the first S-4 MTG-S and MetOp-SG spacecrafts, respectively, S5P (launch: mid 2015) shall minimize gaps in the availability of global atmospheric data products as provided by its predecessor missions SCIAMACHY (Envisat) and OMI (AURA). The satellite's single payload instrument, TROPOMI (TROPOspheric Monitoring Instrument), is jointly developed by The Netherlands and ESA. Covering spectral channels located in the UV, visible, near- and short-wave infrared it will measure various key species including stratospheric ozone, as well as NO2, SO2, CO, CH4, CH2O and aerosols, specifically in the lower Troposphere. The envisaged formation flying with NASA's Suomi NPP satellite will allow use of high spatial resolution imager data for enhanced cloud clearing of the observational data specifically in the short-wave infrared range. An outline of the Sentinel-5P mission objectives will be given. The status of development activities, covering Spacecraft and the Ground Segment will be presented.

  14. Competing Atmospheric and Surface-Driven Impacts of Absorbing Aerosols on the East Asian Summer Monsoon

    Science.gov (United States)

    Persad, G.; Paynter, D.; Ming, Y.; Ramaswamy, V.

    2015-12-01

    Absorbing aerosols, by attenuating shortwave radiation within the atmosphere and reemitting it as longwave radiation, redistribute energy both vertically within the surface-atmosphere column and horizontally between polluted and unpolluted regions. East Asia has the largest concentrations of anthropogenic absorbing aerosols globally, and these, along with the region's scattering aerosols, have both reduced the amount of solar radiation reaching the Earth's surface regionally ("solar dimming") and increased shortwave absorption within the atmosphere, particularly during the peak months of the East Asian Summer Monsoon (EASM). We here analyze how atmospheric absorption and surface solar dimming compete in driving the response of EASM circulation to anthropogenic absorbing aerosols, which dominates, and why—issues of particular importance for predicting how the EASM will respond to projected changes in absorbing and scattering aerosol emissions in the future. We probe these questions in a state-of-the-art general circulation model (GCM) using a combination of realistic and idealized aerosol perturbations that allow us to analyze the relative influence of absorbing aerosols' atmospheric and surface-driven impacts on EASM circulation. In combination, our results make clear that, although absorption-driven dimming has a less detrimental effect on EASM circulation than purely scattering-driven dimming, aerosol absorption is still a net impairment to EASM strength when both its atmospheric and surface effects are considered. Because atmospheric heating is not efficiently conveyed to the surface, the surface dimming and associated cooling from even a pure absorber is sufficient to counteract its atmospheric heating, resulting in a net reduction in EASM strength. These findings elevate the current understanding of the impacts of aerosol absorption on the EASM, improving our ability to diagnose EASM responses to current and future regional changes in aerosol emissions.

  15. Atmospheric Aerosol Analysis using Lightweight Mini GC Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The major components of manmade aerosols are created by the burning of coal and oil. These aerosols are recognized to have a significant climatic impact through...

  16. Atmospheric Aerosol Analysis using Lightweight Mini GC Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The major components of manmade aerosols are created by the burning of coal and oil. Aerosols are recognized to significantly impact the climate through their...

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

    Science.gov (United States)

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

    2013-12-17

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

  18. Remote Sensing of Aerosol in the Terrestrial Atmosphere from Space: New Missions

    Science.gov (United States)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Ivanov, Yu.; Bovchaliuk, A.; Mishchenko, M.; Danylevsky, V.; Sosonkin, M.; Bovchaliuk, V.

    2015-01-01

    The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project Aerosol-UA that obtains data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The project is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

  19. Ångström coefficient as an indicator of the atmospheric aerosol type for a well-mixed atmospheric boundary layer : Part 1: Model development

    NARCIS (Netherlands)

    Kuśmierczyk-Michulec, J.T.

    2009-01-01

    The physical and optical properties of an atmospheric aerosol mixture depend on a number of factors. The relative humidity influences the size of hydroscopic particles and the effective radius of an aerosol mixture. In consequence, values of the aerosol extinction, the aerosol optical thickness and

  20. Vertical profiles of atmospheric fluorescent aerosols observed by a mutil-channel lidar spectrometer system

    Science.gov (United States)

    Huang, Z.; Huang, J.; Zhou, T.; Sugimoto, N.; Bi, J.

    2015-12-01

    Zhongwei Huang1*, Jianping Huang1, Tian Zhou1, Nobuo Sugimoto2, Jianrong Bi1 and Jinsen Shi11Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, China. 2Atmospheric Environment Division, National Institutes for Environmental Studies, Tsukuba, Japan Email: huangzhongwei@lzu.edu.cn Abstract Atmospheric aerosols have a significant impact on regional and globe climate. The challenge in quantifying aerosol direct radiative forcing and aerosol-cloud interactions arises from large spatial and temporal heterogeneity of aerosol concentrations, compositions, sizes, shape and optical properties (IPCC, 2007). Lidar offers some remarkable advantages for determining the vertical structure of atmospheric aerosols and their related optical properties. To investigate the characterization of atmospheric aerosols (especially bioaerosols) with high spatial and temporal resolution, we developed a Raman/fluorescence/polarization lidar system employed a multi-channel spectrometer, with capabilities of providing measurements of Raman scattering and laser-induced fluorescence excitation at 355 nm from atmospheric aerosols. Meanwhile, the lidar system operated polarization measurements both at 355nm and 532nm wavelengths, aiming to obtain more information of aerosols. It employs a high power pulsed laser and a received telescope with 350mm diameter. The receiver could simultaneously detect a wide fluorescent spectrum about 178 nm with spectral resolution 5.7 nm, mainly including an F/3.7 Crossed Czerny-Turner spectrograph, a grating (1200 gr/mm) and a PMT array with 32 photocathode elements. Vertical structure of fluorescent aerosols in the atmosphere was observed by the developed lidar system at four sites across northwest China, during 2014 spring field observation that conducted by Lanzhou University. It has been proved that the developed lidar could detect the fluorescent aerosols with high temporal and

  1. Some results of an experimental study of the atmospheric aerosol in Tomsk: A combined approach

    Energy Technology Data Exchange (ETDEWEB)

    Zuev, V.V. [Institute of Atmospheric Optics, Tomsk (Russian Federation)

    1996-04-01

    As widely accepted, aerosols strongly contribute to the formation of the earth`s radiation balance through the absorption and scattering of solar radiation. In addition, aerosols, being active condensation nuclei, also have a role in the cloud formation process. In this paper, results are presented of aerosol studies undertaken at the field measurement sites of the Institute of Atmospheric Optics in Tomsk and the Tomsk region.

  2. Aerosol influence on energy balance of the middle atmosphere of Jupiter

    Science.gov (United States)

    Zhang, Xi; West, Robert A.; Irwin, Patrick G. J.; Nixon, Conor A.; Yung, Yuk L.

    2015-12-01

    Aerosols are ubiquitous in planetary atmospheres in the Solar System. However, radiative forcing on Jupiter has traditionally been attributed to solar heating and infrared cooling of gaseous constituents only, while the significance of aerosol radiative effects has been a long-standing controversy. Here we show, based on observations from the NASA spacecraft Voyager and Cassini, that gases alone cannot maintain the global energy balance in the middle atmosphere of Jupiter. Instead, a thick aerosol layer consisting of fluffy, fractal aggregate particles produced by photochemistry and auroral chemistry dominates the stratospheric radiative heating at middle and high latitudes, exceeding the local gas heating rate by a factor of 5-10. On a global average, aerosol heating is comparable to the gas contribution and aerosol cooling is more important than previously thought. We argue that fractal aggregate particles may also have a significant role in controlling the atmospheric radiative energy balance on other planets, as on Jupiter.

  3. Aerosol influence on energy balance of the middle atmosphere of Jupiter.

    Science.gov (United States)

    Zhang, Xi; West, Robert A; Irwin, Patrick G J; Nixon, Conor A; Yung, Yuk L

    2015-12-22

    Aerosols are ubiquitous in planetary atmospheres in the Solar System. However, radiative forcing on Jupiter has traditionally been attributed to solar heating and infrared cooling of gaseous constituents only, while the significance of aerosol radiative effects has been a long-standing controversy. Here we show, based on observations from the NASA spacecraft Voyager and Cassini, that gases alone cannot maintain the global energy balance in the middle atmosphere of Jupiter. Instead, a thick aerosol layer consisting of fluffy, fractal aggregate particles produced by photochemistry and auroral chemistry dominates the stratospheric radiative heating at middle and high latitudes, exceeding the local gas heating rate by a factor of 5-10. On a global average, aerosol heating is comparable to the gas contribution and aerosol cooling is more important than previously thought. We argue that fractal aggregate particles may also have a significant role in controlling the atmospheric radiative energy balance on other planets, as on Jupiter.

  4. Assessment of CNRM coupled ocean-atmosphere model sensitivity to the representation of aerosols

    Science.gov (United States)

    Watson, Laura; Michou, Martine; Nabat, Pierre; Saint-Martin, David

    2017-12-01

    Atmospheric aerosols can significantly affect the Earth's radiative balance due to absorption, scattering and aerosol-cloud interactions. Although our understanding of aerosol properties has improved over recent decades, aerosol radiative forcing remains as one of the largest uncertainties when attributing recent and projecting future anthropogenic climate change. Ensembles of a coupled ocean-atmosphere general circulation model were used to investigate how the representation of aerosols within the model can affect climate. The control simulation consisted of a 30-year simulation with an interactive aerosol scheme and aerosol emissions that evolve from 1980-2009. The sensitivity tests included using constant 1980 emissions, using prescribed 2-D monthly mean AODs, modifying the aerosol vertical distribution, altering aerosol optical properties, and changing the parameters used for calculating the aerosol first indirect effect. The results of these sensitivity studies show how modifying certain aspects of the aerosol scheme can significantly affect radiative flux and temperature. In particular, it was shown that compared to the control simulation the use of constant 1980 aerosol emissions decreased the average winter surface temperature of the Arctic by 0.2 K and that the use of prescribed 2-D monthly mean AODs reduced the annual global surface temperature by 0.3 K. Increasing the vertical distribution of anthropogenic aerosols in the model and altering aerosol optical properties modified localised radiative fluxes and temperatures, but the most significant change in global surface temperature (1.3 K) was caused by removing sea salt and organic matter from the calculation of cloud droplet number concentration.

  5. Impact of aerosol heat radiation absorption on the dynamics of an atmospheric boundary layer in equilibrium

    NARCIS (Netherlands)

    Barbaro, E.W.; Vilà-Guerau de Arellano, J.; Krol, M.C.; Holtslag, A.A.M.

    2012-01-01

    The objective of this work is to investigate the influence of the shortwave radiation (SW) absorption by aerosols on the dynamics and heat budget of the atmospheric boundary layer (ABL). This study is relevant for areas characterized by large concentrations of light-absorbing aerosol, which are

  6. Atmospheric aerosol characterization with the Dutch-Chinese FAST formation flying mission

    NARCIS (Netherlands)

    Gill, E.; Maessen, D.; Laan, E.C.; Kraft, S.; Zheng, G.

    2010-01-01

    Large current uncertainties in the characteristics of aerosols in the Earth's atmosphere preclude meaningful climate model evaluation. The FAST mission will contribute to the characterization of aerosols and their relation to climate change through a synoptic evaluation of local, regional and global

  7. An on-line modelling study of the direct effect of atmospheric aerosols over Europe

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, L.; Baro, R.; Jimenez-Guerrero, P.

    2015-07-01

    Atmospheric aerosols affect human health, ecosystems, materials, visibility and Earth’s climate. Those effects are studied in this present work and depend mainly on the aerosol optical properties and how they influence the Earth’s radiation budget. Such properties can be divided on direct and semi-direct effect, produced by the scattering and absorption of radiation; and indirect effect, which influences the aerosols-cloud interactions. The aim of this work is to assess the direct effect through the study of the mean temperature; the radiation that reaches the Earth’s surface and at the top of the atmosphere; and the interaction of these meteorological variables with particulate matter (PM10). Results indicate decreases in temperature and radiation that reaches the Earth's surface, together with increases in the outgoing radiation at top of the atmosphere, and changes in the particulate matter, thus proving a colder climate due to the direct effect of atmospheric aerosols. (Author)

  8. An on-line modelling study of the direct effect of atmospheric aerosols over Europe

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, L.; Baro, R.; Jimenez-Guerrero, P.

    2015-07-01

    Atmospheric aerosols affect human health, ecosystems, materials, visibility and Earths climate. Those effects are studied in this present work and depend mainly on the aerosol optical properties and how they influence the Earths radiation budget. Such properties can be divided on direct and semi-direct effect, produced by the scattering and absorption of radiation; and indirect effect, which influences the aerosols-cloud interactions. The aim of this work is to assess the direct effect through the study of the mean temperature; the radiation that reaches the Earths surface and at the top of the atmosphere; and the interaction of these meteorological variables with particulate matter (PM10). Results indicate decreases in temperature and radiation that reaches the Earth's surface, together with increases in the outgoing radiation at top of the atmosphere, and changes in the particulate matter, thus proving a colder climate due to the direct effect of atmospheric aerosols. (Author)

  9. Regional effects of atmospheric aerosols on temperature: an evaluation of an ensemble of online coupled models

    Science.gov (United States)

    Baró, Rocío; Palacios-Peña, Laura; Baklanov, Alexander; Balzarini, Alessandra; Brunner, Dominik; Forkel, Renate; Hirtl, Marcus; Honzak, Luka; Pérez, Juan Luis; Pirovano, Guido; San José, Roberto; Schröder, Wolfram; Werhahn, Johannes; Wolke, Ralf; Žabkar, Rahela; Jiménez-Guerrero, Pedro

    2017-08-01

    The climate effect of atmospheric aerosols is associated with their influence on the radiative budget of the Earth due to the direct aerosol-radiation interactions (ARIs) and indirect effects, resulting from aerosol-cloud-radiation interactions (ACIs). Online coupled meteorology-chemistry models permit the description of these effects on the basis of simulated atmospheric aerosol concentrations, although there is still some uncertainty associated with the use of these models. Thus, the objective of this work is to assess whether the inclusion of atmospheric aerosol radiative feedbacks of an ensemble of online coupled models improves the simulation results for maximum, mean and minimum temperature at 2 m over Europe. The evaluated models outputs originate from EuMetChem COST Action ES1004 simulations for Europe, differing in the inclusion (or omission) of ARI and ACI in the various models. The cases studies cover two important atmospheric aerosol episodes over Europe in the year 2010: (i) a heat wave event and a forest fire episode (July-August 2010) and (ii) a more humid episode including a Saharan desert dust outbreak in October 2010. The simulation results are evaluated against observational data from the E-OBS gridded database. The results indicate that, although there is only a slight improvement in the bias of the simulation results when including the radiative feedbacks, the spatiotemporal variability and correlation coefficients are improved for the cases under study when atmospheric aerosol radiative effects are included.

  10. Constraining the atmospheric composition of the day-night terminators of HD 189733b: Atmospheric retrieval with aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Min [Institute for Computational Science, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Irwin, Patrick G. J.; Fletcher, Leigh N.; Barstow, Joanna K. [Department of Atmospheric, Oceanic, and Planetary Physics, University of Oxford, OX1 3PU Oxford (United Kingdom); Heng, Kevin, E-mail: lee@physik.uzh.ch [Center for Space and Habitability, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2014-07-01

    A number of observations have shown that Rayleigh scattering by aerosols dominates the transmission spectrum of HD 189733b at wavelengths shortward of 1 μm. In this study, we retrieve a range of aerosol distributions consistent with transmission spectroscopy between 0.3-24 μm that were recently re-analyzed by Pont et al. To constrain the particle size and the optical depth of the aerosol layer, we investigate the degeneracies between aerosol composition, temperature, planetary radius, and molecular abundances that prevent unique solutions for transit spectroscopy. Assuming that the aerosol is composed of MgSiO{sub 3}, we suggest that a vertically uniform aerosol layer over all pressures with a monodisperse particle size smaller than about 0.1 μm and an optical depth in the range 0.002-0.02 at 1 μm provides statistically meaningful solutions for the day/night terminator regions of HD 189733b. Generally, we find that a uniform aerosol layer provide adequate fits to the data if the optical depth is less than 0.1 and the particle size is smaller than 0.1 μm, irrespective of the atmospheric temperature, planetary radius, aerosol composition, and gaseous molecules. Strong constraints on the aerosol properties are provided by spectra at wavelengths shortward of 1 μm as well as longward of 8 μm, if the aerosol material has absorption features in this region. We show that these are the optimal wavelengths for quantifying the effects of aerosols, which may guide the design of future space observations. The present investigation indicates that the current data offer sufficient information to constrain some of the aerosol properties of HD189733b, but the chemistry in the terminator regions remains uncertain.

  11. SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western...

  12. Infrared remote sensing of atmospheric aerosols; Apports du sondage infrarouge a l'etude des aerosols atmospheriques

    Energy Technology Data Exchange (ETDEWEB)

    Pierangelo, C.

    2005-09-15

    The 2001 report from the Intergovernmental Panel on Climate Change emphasized the very low level of understanding of atmospheric aerosol effects on climate. These particles originate either from natural sources (dust, volcanic aerosols...) or from anthropogenic sources (sulfates, soot...). They are one of the main sources of uncertainty on climate change, partly because they show a very high spatio-temporal variability. Observation from space, being global and quasi-continuous, is therefore a first importance tool for aerosol studies. Remote sensing in the visible domain has been widely used to obtain a better characterization of these particles and their effect on solar radiation. On the opposite, remote sensing of aerosols in the infrared domain still remains marginal. Yet, not only the knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing, but also infrared remote sensing provides a way to retrieve other aerosol characteristics (observations are possible at night and day, over land and sea). In this PhD dissertation, we show that aerosol optical depth, altitude and size can be retrieved from infrared sounder observations. We first study the sensitivity of aerosol optical properties to their micro-physical properties, we then develop a radiative transfer code for scattering medium adapted to the very high spectral resolution of the new generation sounder NASA-Aqua/AIRS, and we finally focus on the inverse problem. The applications shown here deal with Pinatubo stratospheric volcanic aerosol, observed with NOAA/HIRS, and with the building of an 8 year climatology of dust over sea and land from this sounder. Finally, from AIRS observations, we retrieve the optical depth at 10 {mu}m, the average altitude and the coarse mode effective radius of mineral dust over sea. (author)

  13. Climate-Relevant Properties of Atmospheric Aerosols Over Megacity Regions in China

    Science.gov (United States)

    Andreae, M. O.; Garland, R.; Gunthe, S.; Poeschl, U.; Rose, D.; Schmid, O.; Yang, H.; Zhang, Y.; Zhu, T.

    2007-12-01

    We conducted measurements of optical and cloud-nucleating properties of the atmospheric aerosol over urban and peri-urban regions in northern and southern China (Beijing and Guangzhou areas). We measured light scattering with a nephelometer at several wavelengths and light absorption with a photoacoustic spectrometer at 532 nm. Because the latter instrument measures the absorption on airborne particles, it is free from filter artefacts and provides high accuracy. The cloud-nucleating properties of size-selected aerosol were determined with a DMT CCN counter. Urban aerosols were found to be highly absorbing, as a result of strong emissions of soot particles mostly from vehicular sources. Regional aerosols were somewhat less absorbing due to the continued production of secondary inorganic (sulfate, nitrate) and organic aerosol. Aerosol from biomass burning also made substantial contributions to the atmospheric burden. Absolute values of the scattering and absorption coefficients were very high, especially during the northeastern monsoon in Guangzhou. A negative correlation between single scattering albedo and backscatter fraction was observed and found to have a strong non-linear effect on aerosol radiative forcing efficiency. High CCN concentrations were present over both regions. In spite of the relatively young age of the aerosols, most of the particles contained enough soluble material to be able to activate at intermediate supersaturations. The hygroscopicity of the particles was in general similar or higher than that observed in regional aerosol from Europe or other polluted regions.

  14. [A review of atmospheric aerosol research by using polarization remote sensing].

    Science.gov (United States)

    Guo, Hong; Gu, Xing-Fa; Xie, Dong-Hai; Yu, Tao; Meng, Qing-Yan

    2014-07-01

    In the present paper, aerosol research by using polarization remote sensing in last two decades (1993-2013) was reviewed, including aerosol researches based on POLDER/PARASOL, APS(Aerosol Polarimetry Sensor), Polarized Airborne camera and Ground-based measurements. We emphasize the following three aspects: (1) The retrieval algorithms developed for land and marine aerosol by using POLDER/PARASOL; The validation and application of POLDER/PARASOL AOD, and cross-comparison with AOD of other satellites, such as MODIS AOD. (2) The retrieval algorithms developed for land and marine aerosol by using MICROPOL and RSP/APS. We also introduce the new progress in aerosol research based on The Directional Polarimetric Camera (DPC), which was produced by Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (CAS). (3) The aerosol retrieval algorithms by using measurements from ground-based instruments, such as CE318-2 and CE318-DP. The retrieval results from spaceborne sensors, airborne camera and ground-based measurements include total AOD, fine-mode AOD, coarse-mode AOD, size distribution, particle shape, complex refractive indices, single scattering albedo, scattering phase function, polarization phase function and AOD above cloud. Finally, based on the research, the authors present the problems and prospects of atmospheric aerosol research by using polarization remote sensing, and provide a valuable reference for the future studies of atmospheric aerosol.

  15. Organic Mass to Organic Carbon ratio in Atmospheric Aerosols: Observations and Global Simulations

    Science.gov (United States)

    Tsigaridis, K.; Kanakidou, M.; Daskalakis, N.

    2012-12-01

    Organic compounds play an important role in atmospheric chemistry and affect Earth's climate through their impact on oxidants and aerosol formation (e.g. O3 and organic aerosols (OA)). Due to the complexity of the mixture of organics in the atmosphere, the organic-mass-to-organic-carbon ratio (OM/OC) is often used to characterize the organic component in atmospheric aerosols. This ratio varies dependant on the aerosol origin and the chemical processing in the atmosphere. Atmospheric observations have shown that as OA and its precursor gases age in the atmosphere, it leads to the formation of more oxidized (O:C atomic ratio 0.6 to 0.8), less volatile and less hydrophobic compounds (particle growth factor at 95% relative humidity of 0.16 to 0.20) that have more similar properties than fresh aerosols. While reported OM:OC ratios observed over USA range between 1.29 and 1.95, indicating significant contribution of local pollution sources to the OC in that region, high O/C ratio associated with a high OM/OC ratio of 2.2 has been also observed for the summertime East Mediterranean aged aerosol. In global models, the OM/OC ratio is either calculated for specific compounds or estimated for compound groups. In the present study, we review OM/OC observations and compare them with simulations from a variety of models that contributed to the AEROCOM exercise. We evaluate the chemical processing level of atmospheric aerosols simulated by the models. A total of 32 global chemistry transport models are considered in this study with variable complexity of the representation of OM/OC ratio in the OA. The analysis provides an integrated view of the OM/OC ratio in the global atmosphere and of the accuracy of its representation in the global models. Implications for atmospheric chemistry and climate simulations are discussed.

  16. Aerosol detection using lidar-based atmospheric profiling

    Science.gov (United States)

    Elbakary, Mohamed I.; Abdelghaffar, Hossam M.; Afrifa, Kwasi; Rakha, Hesham A.; Cetin, Mecit; Iftekharuddin, Khan M.

    2017-08-01

    A compact light detection and ranging (LiDAR) is a system that provides aerosols profile measurements by identifying the aerosol scattering ratio as function of the altitude. The aerosol scattering ratios are used to obtain multiple aerosol intensive ratio parameters known as backscatter color ratio, depolarization ratio, and lidar ratio. The aerosol ratio parameters are known to vary with aerosol type, size, and shape. In this paper, we employed lidar measurements to detect the potential source of the aerosol in the neighborhood of the campus of Old Dominion University. The lidar is employed to collect measurements at several locations in the area of study. Then, the lidar ratio and the color ratio are retrieved from collected measurements. To find the source of aerosol in the measurements, a tracking algorithm is implemented and employed to track the concentration of that pollution in the data. The results show that the source of soot pollution in the area of study is Hampton Blvd, a major street, in the area of the campus where the diesel trucks travel between the ports in the city of Norfolk.

  17. Volatile properties of atmospheric aerosols during nucleation events ...

    Indian Academy of Sciences (India)

    C temperatures. Averaged monthly aerosol concen- tration is at its maximum in November and gradually decreases to its minimum at the end of March. The diurnal variations of aerosol concentrations gradually decrease in the night and in early morning hours (0400–0800 hr). However, concentration attains minimum in its ...

  18. Study of total column atmospheric aerosol optical depth, ozone and ...

    Indian Academy of Sciences (India)

    Extensive observations of the columnar aerosol optical depth (AOD), total column ozone (TCO) and precipitable water content (PWC) have been carried out using the on-line, multi-band solar radiometers onboard ORV Sagar Kanya (Cruise#SK 147B) over Bay of Bengal during 11th-28th August 1999. Aerosol optical and ...

  19. The EOF method applied to approximate the atmospheric aerosol PSD

    NARCIS (Netherlands)

    Kusmierczyk-Michulec J.T.

    2008-01-01

    Examples of the approximation of the aerosol size distributions with EOFs are given here by using data from a set of 2449 aerosol size distribution profiles measured during the Rough Evaporation Duck (RED) experiment that took place off Oahu, Hawaii, from 26 August to 15 September 2001. The

  20. Global atmospheric sulfur budget under volcanically quiescent conditions: Aerosol-chemistry-climate model predictions and validation

    Science.gov (United States)

    Sheng, Jian-Xiong; Weisenstein, Debra K.; Luo, Bei-Ping; Rozanov, Eugene; Stenke, Andrea; Anet, Julien; Bingemer, Heinz; Peter, Thomas

    2015-01-01

    The global atmospheric sulfur budget and its emission dependence have been investigated using the coupled aerosol-chemistry-climate model SOCOL-AER. The aerosol module comprises gaseous and aqueous sulfur chemistry and comprehensive microphysics. The particle distribution is resolved by 40 size bins spanning radii from 0.39 nm to 3.2 μm, including size-dependent particle composition. Aerosol radiative properties required by the climate model are calculated online from the aerosol module. The model successfully reproduces main features of stratospheric aerosols under nonvolcanic conditions, including aerosol extinctions compared to Stratospheric Aerosol and Gas Experiment II (SAGE II) and Halogen Occultation Experiment, and size distributions compared to in situ measurements. The calculated stratospheric aerosol burden is 109 Gg of sulfur, matching the SAGE II-based estimate (112 Gg). In terms of fluxes through the tropopause, the stratospheric aerosol layer is due to about 43% primary tropospheric aerosol, 28% SO2, 23% carbonyl sulfide (OCS), 4% H2S, and 2% dimethyl sulfide (DMS). Turning off emissions of the short-lived species SO2, H2S, and DMS shows that OCS alone still establishes about 56% of the original stratospheric aerosol burden. Further sensitivity simulations reveal that anticipated increases in anthropogenic SO2 emissions in China and India have a larger influence on stratospheric aerosols than the same increase in Western Europe or the U.S., due to deep convection in the western Pacific region. However, even a doubling of Chinese and Indian emissions is predicted to increase the stratospheric background aerosol burden only by 9%. In contrast, small to moderate volcanic eruptions, such as that of Nabro in 2011, may easily double the stratospheric aerosol loading.

  1. Monitoring and characterization of atmospheric aerosols with Raman and dual-polarization lidars

    Science.gov (United States)

    Royer, P.; Sauvage, L.; Bizard, A.; Thobois, L.

    2013-10-01

    Atmospheric aerosols play a key role on climate balance (direct, semi-direct and indirect effects), on human health (increase of breathing problems and lung cancer for pollution aerosols) and human activities (damage to aircraft engines by volcanic ashes, reduction of visibility by dust or pollution aerosols). In order to monitor and characterize this threat it is necessary to localize, characterize and possibly quantify the presence of aerosols in the atmosphere from the lowest layers (~100 m) up to the tropopause (18 km). We use here an approach based on measurements of the new Raman and dual-polarization LiDAR R-Man510. We present in this paper how it is possible to detect atmospheric layers, to retrieve their optical properties and to classify these layers with this sensor.

  2. Scanning Transmission X-ray Microscopy: Applications in Atmospheric Aerosol Research

    Energy Technology Data Exchange (ETDEWEB)

    Moffet, Ryan C.; Tivanski, Alexei V.; Gilles, Mary K.

    2011-01-20

    Scanning transmission x-ray microscopy (STXM) combines x-ray microscopy and near edge x-ray absorption fine structure spectroscopy (NEXAFS). This combination provides spatially resolved bonding and oxidation state information. While there are reviews relevant to STXM/NEXAFS applications in other environmental fields (and magnetic materials) this chapter focuses on atmospheric aerosols. It provides an introduction to this technique in a manner approachable to non-experts. It begins with relevant background information on synchrotron radiation sources and a description of NEXAFS spectroscopy. The bulk of the chapter provides a survey of STXM/NEXAFS aerosol studies and is organized according to the type of aerosol investigated. The purpose is to illustrate the current range and recent growth of scientific investigations employing STXM-NEXAFS to probe atmospheric aerosol morphology, surface coatings, mixing states, and atmospheric processing.

  3. CCN activity of secondary aerosols from terpene ozonolysis under atmospheric relevant conditions

    Science.gov (United States)

    Yuan, Cheng; Ma, Yan; Diao, Yiwei; Yao, Lei; Zhou, Yaoyao; Wang, Xing; Zheng, Jun

    2017-04-01

    Gas-phase ozonolysis of terpenes is an important source of atmospheric secondary organic aerosol. The contribution of terpene-derived aerosols to the atmospheric cloud condensation nucleus (CCN) burden under atmospheric conditions, however, remains highly uncertain. The results obtained in previous studies under simple laboratory conditions may not be applicable to atmospheric relevant conditions. Here we present that CCN activities of aerosols from terpene ozonolysis can be significantly affected by atmospheric relevant species that can act as stabilized Criegee intermediate (SCI) or OH scavengers. Ozonolysis reactions of α-pinene, limonene, α-cedrene, and α-humulene were conducted in a 4.5 m3 collapsible fluoropolymer chamber at near-atmospheric concentrations in the presence of different OH scavengers (cyclohexane, 2-butanol, or CO) and SCI scavengers (CH3COOH, H2O, or SO2). The number size distribution and CCN activity of aerosol particles formed during ozonolysis were simultaneously determined. Additionally, particulate products were chemically analyzed by using a Filter Inlet for Gases and AEROsols High-Resolution Time-of-Flight Chemical-Ionization Mass Spectrometer. Results showed that aerosol CCN activity following monoterpene ozonolysis was more sensitive to the choice of OH scavengers, while that from sesquiterpene ozonolysis was significantly affected by SCI scavengers. Combined with chemical analysis results, it was concluded that the unimolecular decomposition of CIs giving hygroscopic organic products can be largely suppressed by bimolecular reactions during sesquiterpene ozonolysis but was not significantly impacted in monoterpene ozonolysis. Our study underscores the key role of CIs in the CCN activity of terpene ozonolysis-derived aerosols. The effects of atmospheric relevant species (e.g., SO2, H2O, and CO) need to be considered when assessing the contribution of biogenic terpenes to the atmospheric CCN burden under ambient conditions.

  4. Atmospheric sulphuric acid and aerosol formation: implications from atmospheric measurements for nucleation and early growth mechanisms

    Directory of Open Access Journals (Sweden)

    S.-L. Sihto

    2006-01-01

    Full Text Available We have investigated the formation and early growth of atmospheric secondary aerosol particles building on atmospheric measurements. The measurements were part of the QUEST 2 campaign which took place in spring 2003 in Hyytiälä (Finland. During the campaign numerous aerosol particle formation events occurred of which 15 were accompanied by gaseous sulphuric acid measurements. Our detailed analysis of these 15 events is focussed on nucleation and early growth (to a diameter of 3 nm of fresh particles. It revealed that new particle formation seems to be a function of the gaseous sulphuric acid concentration to the power from one to two when the time delay between the sulphuric acid and particle number concentration is taken into account. From the time delay the growth rates of freshly nucleated particles from 1 nm to 3 nm were determined. The mean growth rate was 1.2 nm/h and it was clearly correlated with the gaseous sulphuric acid concentration. We tested two nucleation mechanisms – recently proposed cluster activation and kinetic type nucleation – as possible candidates to explain the observed dependences, and determined experimental nucleation coefficients. We found that some events are dominated by the activation mechanism and some by the kinetic mechanism. Inferred coefficients for the two nucleation mechanisms are the same order of magnitude as chemical reaction coefficients in the gas phase and they correlate with the product of gaseous sulphuric acid and ammonia concentrations. This indicates that besides gaseous sulphuric acid also ammonia has a role in nucleation.

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

    Science.gov (United States)

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

    2006-12-01

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

  6. SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

    Data.gov (United States)

    National Aeronautics and Space Administration — In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western Zambia from...

  7. Distribution of atmospheric aerosols and CO2 lidar backscatter simulation

    Science.gov (United States)

    Kent, G. S.; Wang, P. H.; Deepak, A.; Farrukh, U. O.

    1985-01-01

    Development of a Global Wind Measurement Satellite System (WINDSAT) (NOAA, 1981) requires a knowledge of the global characteristics of the free tropospheric and lower stratospheric aerosol. In particular, there is a need to document the behavior of the aerosol backscattering function, at CO2 laser wavelengths, beta sub CO2, as a function of space and time. There is, however, a relative lack of data for the free troposphere, particularly over the remoter regions of the globe, as compared with that for the boundary layer and the stratosphere. Moreover, because of variations in concentration that occur as a function of space and time, large data sets are required to obtain meaningful averages. A recent study by Kent et al. (1985) uses three distinct tropospheric aerosol data sets in order to obtain an improved global model of the general aerosol characteristics, including variation of beta sub CO2 with latitude, season, and altitude. The more important findings are summarized.

  8. Aerosol Type Constraints Required for Ocean Color Atmospheric Correction

    Science.gov (United States)

    Kahn, R.; Ahmad, Z.; Franz, B.; Massie, S.; Sayer, A.

    2014-01-01

    Organizers of the Aerosol Cloud Ecosystem (ACE) Science Working Group held a workshop at Goddard Space Flight Center June 16-18, 2014; speaker presentations will be made available on the ACE public website.

  9. A new climatology for atmospheric correction based on the aerosol inherent optical properties

    Science.gov (United States)

    Zagolski, Francis; Santer, Richard; Aznay, Ouahid

    2007-07-01

    In the aerosol remote sensing algorithms over ocean, the aerosol models are deduced from the spectral dependence of the path radiances in the near-infrared region. In the classical scheme of atmospheric corrections, the key point is the derivation of atmospheric signals in the visible part of the solar spectrum using these aerosol models. The aerosol climatology generally includes the standard aerosol models. Nevertheless, the latter may not be representative enough of the variety of aerosols encountered over coastal areas. One way to extend this climatology is to generate additional aerosol models. The latters will be described by their micro-physical properties and their inherent optical properties (IOPs) can then be computed with the Mie's theory. Coastal and inland stations of CIMEL sun-photometers from the AERONET (AErosol RObotic NETwork) offer an extensive and representative data set of aerosol characteristics (i.e., the apparent optical properties from which can be derived the IOPs) in the marine environment through solar extinction and sky radiance measurements. An iterative method, developed at the ≪ Laboratoire Interdisciplinaire des Sciences de l'Environnement ≫ (LISE, Wimereux-France), allows to extract the aerosol phase function from these ground-based measurements. CIMEL data, collected over 25 stations during several years, were processed to build-up a database with more than 7000 sequences including single scattering albedos and phase functions at two wavelengths (675 nm and 870 nm). Statistical methods have been applied on this data set to discard the wrong sequences and to suggest a classification in aerosol models through their IOPs.

  10. A Decade of Field Changing Atmospheric Aerosol Research: Outcomes of EPA’s STAR Program

    Science.gov (United States)

    Conference: Gordon Research Conference in Atmospheric Chemistry, July 28 – August 2, 2013, VermontPresentation Type: PosterTitle: An Analysis of EPA’s STAR Program and a Decade of Field Changing Research in Atmospheric AerosolsAuthors: Kristina M. Wagstrom1,2, Sherri ...

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

    Science.gov (United States)

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

    2015-05-14

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

  12. Distributions and climate effects of atmospheric aerosols from the preindustrial era to 2100 along Representative Concentration Pathways (RCPs simulated using the global aerosol model SPRINTARS

    Directory of Open Access Journals (Sweden)

    T. Takemura

    2012-12-01

    Full Text Available Global distributions and associated climate effects of atmospheric aerosols were simulated using a global aerosol climate model, SPRINTARS, from 1850 to the present day and projected forward to 2100. Aerosol emission inventories used by the Coupled Model Intercomparison Project Phase 5 (CMIP5 were applied to this study. Scenarios based on the Representative Concentration Pathways (RCPs were used for the future projection. Aerosol loading in the atmosphere has already peaked and is now reducing in Europe and North America. However, in Asia where rapid economic growth is ongoing, aerosol loading is estimated to reach a maximum in the first half of this century. Atmospheric aerosols originating from the burning of biomass have maintained high loadings throughout the 21st century in Africa, according to the RCPs. Evolution of the adjusted forcing by direct and indirect aerosol effects over time generally correspond to the aerosol loading. The probable future pathways of global mean forcing differ based on the aerosol direct effect for different RCPs. Because aerosol forcing will be close to the preindustrial level by the end of the 21st century for all RCPs despite the continuous increases in greenhouse gases, global warming will be accelerated with reduced aerosol negative forcing.

  13. Aerosols in the Convective Boundary Layer: Radiation Effects on the Coupled Land-Atmosphere System

    Science.gov (United States)

    Barbaro, E.; Vila-Guerau Arellano, J.; Ouwersloot, H. G.; Schroter, J.; Donovan, D. P.; Krol, M. C.

    2013-12-01

    We investigate the responses of the surface energy budget and the convective boundary-layer (CBL) dynamics to the presence of aerosols using a combination of observations and numerical simulations. A detailed observational dataset containing (thermo)dynamic variables observed at CESAR (Cabauw Experimental Site for Atmospheric Research) and aerosol information from the European Integrated Project on Aerosol, Cloud, Climate, and Air Quality Interactions (IMPACT/EUCAARI) campaign is employed to design numerical experiments reproducing two prototype clear-sky days characterized by: (i) a well-mixed residual layer above a ground inversion and (ii) a continuously growing CBL. A large-eddy simulation (LES) model and a mixed-layer (MXL) model, both coupled to a broadband radiative transfer code and a land-surface model, are used to study the impacts of aerosol scattering and absorption of shortwave radiation on the land-atmosphere system. We successfully validate our model results using the measurements of (thermo)dynamic variables and aerosol properties for the two different CBL prototypes studied here. Our findings indicate that in order to reproduce the observed surface energy budget and CBL dynamics, information of the vertical structure and temporal evolution of the aerosols is necessary. Given the good agreement between the LES and the MXL model results, we use the MXL model to explore the aerosol effect on the land-atmosphere system for a wide range of optical depths and single scattering albedos. Our results show that higher loads of aerosols decrease irradiance, imposing an energy restriction at the surface. Over the studied well-watered grassland, aerosols reduce the sensible heat flux more than the latent heat flux. As a result, aerosols increase the evaporative fraction. Moreover, aerosols also delay the CBL morning onset and anticipate its afternoon collapse. If also present above the CBL during the morning transition, aerosols maintain a persistent near

  14. Atmospheric aerosols versus greenhouse gases in the twenty-first century.

    Science.gov (United States)

    Andreae, Meinrat O

    2007-07-15

    Looked at in a simplistic way, aerosols have counteracted the warming effects of greenhouse gases (GHG) over the past century. This has not only provided some 'climate protection', but also prevented the true magnitude of the problem from becoming evident. In particular, it may have resulted in an underestimation of the sensitivity of the climate system to the effect of GHG. Over the present century, the role of aerosols in opposing global warming will wane, as there are powerful policy reasons to reduce their emissions and their atmospheric lifetimes are short in contrast to those of the GHG. On the other hand, aerosols will continue to play a role in regional climate change, especially with regard to the water cycle. The end of significant climate protection by atmospheric aerosols, combined with the potentially very high sensitivity of the climate system, makes sharp and prompt reductions in greenhouse gas emissions, especially CO2, very urgent.

  15. Regional effects of atmospheric aerosols on temperature: an evaluation of an ensemble of online coupled models

    Directory of Open Access Journals (Sweden)

    R. Baró

    2017-08-01

    Full Text Available The climate effect of atmospheric aerosols is associated with their influence on the radiative budget of the Earth due to the direct aerosol–radiation interactions (ARIs and indirect effects, resulting from aerosol–cloud–radiation interactions (ACIs. Online coupled meteorology–chemistry models permit the description of these effects on the basis of simulated atmospheric aerosol concentrations, although there is still some uncertainty associated with the use of these models. Thus, the objective of this work is to assess whether the inclusion of atmospheric aerosol radiative feedbacks of an ensemble of online coupled models improves the simulation results for maximum, mean and minimum temperature at 2 m over Europe. The evaluated models outputs originate from EuMetChem COST Action ES1004 simulations for Europe, differing in the inclusion (or omission of ARI and ACI in the various models. The cases studies cover two important atmospheric aerosol episodes over Europe in the year 2010: (i a heat wave event and a forest fire episode (July–August 2010 and (ii a more humid episode including a Saharan desert dust outbreak in October 2010. The simulation results are evaluated against observational data from the E-OBS gridded database. The results indicate that, although there is only a slight improvement in the bias of the simulation results when including the radiative feedbacks, the spatiotemporal variability and correlation coefficients are improved for the cases under study when atmospheric aerosol radiative effects are included.

  16. Modeling the evolution of the aerosol cloud of toxicants in the atmosphere

    Directory of Open Access Journals (Sweden)

    Bondarchuk Ivan

    2017-01-01

    Full Text Available Using the methods of mathematical modeling, the formation and evolution of aerosol clouds of toxicants in the atmosphere from the chemical industry enterprises, thermal power engineering and rocket carriers of space vehicles is analyzed. The processes of dynamic interaction of drops between themselves and a two-phase flow, processes of agglomeration, crushing and evaporation of aerosol particles are taken into account. The results of numerical calculations are presented.

  17. Relay transport of aerosols to Beijing-Tianjin-Hebei region by multi-scale atmospheric circulations

    Science.gov (United States)

    Miao, Yucong; Guo, Jianping; Liu, Shuhua; Liu, Huan; Zhang, Gen; Yan, Yan; He, Jing

    2017-09-01

    The Beijing-Tianjin-Hebei (BTH) region experiences heavy aerosol pollution, which is found to have close relationships with the synoptic- and local-scale atmospheric circulations. However, how and to what extent these multi-scale circulations interplay to modulate aerosol transport have not been fully understood. To this end, this study comprehensively investigated the impacts of these circulations on aerosol transport in BTH by focusing on an episode occurred on 1 June 2013 through combining both observations and three-dimensional simulations. It was found that during this episode, the Bohai Sea acted as a transfer station, and the high-pressure system over the Yellow Sea and sea-breeze in BTH took turns to affect the transport of aerosols. In the morning, influenced by the high-pressure system, lots of aerosols emitted from Shandong and Jiangsu provinces were first transported to the Bohai Sea. After then, these aerosols were brought to the BTH region in the afternoon through the inland penetration of sea-breeze, significantly exacerbating the air quality in BTH. The inland penetration of sea-breeze could be identified by the sharp changes in ground-based observed temperature, humidity, and wind when the sea-breeze front (SBF) passed by. Combining observations with model outputs, the SBF was found to be able to advance inland more than ∼150 km till reaching Beijing. This study has important implications for better understanding the aerosol transport in BTH, and improving the forecast of such aerosol pollution.

  18. pH of Aerosols in a Polluted Atmosphere: Source Contributions to Highly Acidic Aerosol.

    Science.gov (United States)

    Shi, Guoliang; Xu, Jiao; Peng, Xing; Xiao, Zhimei; Chen, Kui; Tian, Yingze; Guan, Xinbei; Feng, Yinchang; Yu, Haofei; Nenes, Athanasios; Russell, Armistead G

    2017-04-18

    Acidity (pH) plays a key role in the physical and chemical behavior of PM2.5. However, understanding of how specific PM sources impact aerosol pH is rarely considered. Performing source apportionment of PM2.5 allows a unique link of sources pH of aerosol from the polluted city. Hourly water-soluble (WS) ions of PM2.5 were measured online from December 25th, 2014 to June 19th, 2015 in a northern city in China. Five sources were resolved including secondary nitrate (41%), secondary sulfate (26%), coal combustion (14%), mineral dust (11%), and vehicle exhaust (9%). The influence of source contributions to pH was estimated by ISORROPIA-II. The lowest aerosol pH levels were found at low WS-ion levels and then increased with increasing total ion levels, until high ion levels occur, at which point the aerosol becomes more acidic as both sulfate and nitrate increase. Ammonium levels increased nearly linearly with sulfate and nitrate until approximately 20 μg m-3, supporting that the ammonium in the aerosol was more limited by thermodynamics than source limitations, and aerosol pH responded more to the contributions of sources such as dust than levels of sulfate. Commonly used pH indicator ratios were not indicative of the pH estimated using the thermodynamic model.

  19. Nucleation and Atmospheric Aerosols 17th International Conference, Galway, Ireland, 2007

    CERN Document Server

    O'Dowd, Colin D

    2007-01-01

    Atmospheric particles are ubiquitous in the atmosphere: they form the seeds for cloud droplets and they form haze layers, blocking out incoming radiation and contributing to a partial cooling of our climate. They also contribute to poor air quality and health impacts. A large fraction of aerosols are formed from nucleation processes – that is a phase transition from vapour to liquid or solid particles. Examples are the formation of stable clusters about 1 nm in size from molecular collisions and these in turn can grow into larger (100 nm or more) haze particles via condensation to the formation of ice crystals in mixed phase or cold clouds. This book brings together the leading experts from the nucleation and atmospheric aerosols research communities to present the current state-of-the-art knowledge in these related fields. Topics covered are: Nucleation Experiment & Theory, Binary, Homogeneous and Heterogeneous Nucleation, Ion & Cluster Properties During Nucleation, Aerosol Characterisation & P...

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

    Science.gov (United States)

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

    2013-12-01

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

  1. Possible sources of atmospheric aerosol during 2005/06 Harmattan ...

    African Journals Online (AJOL)

    ... higher contribution of black carbon particles than the coarse fraction. Two source profiles were identified in the fine fraction of the aerosol and four source profiles in the coarse fraction. The experimental and modeled particulate mass correlated well, with 0.93 ≤ R2 ≤ 0.95. Journal of Applied Science and Technology Vol.

  2. Distribution of Atmospheric Aerosol over the South China Sea

    Directory of Open Access Journals (Sweden)

    Shih-Jen Huang

    2015-01-01

    Full Text Available The satellite-derived aerosol optical depth (AOD data is used to investigate the distribution of aerosol over the South China Sea (SCS. High correlation coefficients are found between in situ AERONET data and satellite AOD measurements around the SCS with the highest coefficient of 0.9 on the Dongsha Island (i.e., Pratas Island. The empirical orthogonal function (EOF analysis of AOD over the SCS shows that high AOD is always found around offshore areas of China, Indochina, Sumatra, and Borneo. Besides, spring is the major season of occurring coarse aerosol particles (AOT_C but fine aerosol particles (AOT_F occur yearly. The biomass burning is found in Indochina during March and April, and so it is in Sumatra and Borneo from August to October. The results also show that the AOT_F are higher during El Niño events, but higher AOT_C are found in La Niña years.

  3. Fractionation of Stable Isotopes in Atmospheric Aerosol Reactions

    DEFF Research Database (Denmark)

    Meusinger, Carl

    as required. The kndings provide important results for the studies' respective felds, including a description of the isotopic fractionation and quantum yield of nitrate photolysis in snow, equilibrium fractionation in secondary organic aerosol and fractionation constants of different oxidation pathways of SO2....

  4. Study of total column atmospheric aerosol optical depth, ozone and ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    total column ozone (TCO) and precipitable water content (PWC) have been carried out using the on-line, multi-band solar radiometers onboard ORV Sagar Kanya (Cruise # SK 147B) over Bay of Bengal during 11th–28th August 1999. Aerosol optical and physical properties (optical depth and angstrom parameter) have ...

  5. Modelling iodide – iodate speciation in atmospheric aerosol: Contributions of inorganic and organic iodine chemistry

    Directory of Open Access Journals (Sweden)

    S. Pechtl

    2007-01-01

    Full Text Available The speciation of iodine in atmospheric aerosol is currently poorly understood. Models predict negligible iodide concentrations but accumulation of iodate in aerosol, both of which is not confirmed by recent measurements. We present an updated aqueous phase iodine chemistry scheme for use in atmospheric chemistry models and discuss sensitivity studies with the marine boundary layer model MISTRA. These studies show that iodate can be reduced in acidic aerosol by inorganic reactions, i.e., iodate does not necessarily accumulate in particles. Furthermore, the transformation of particulate iodide to volatile iodine species likely has been overestimated in previous model studies due to negligence of collision-induced upper limits for the reaction rates. However, inorganic reaction cycles still do not seem to be sufficient to reproduce the observed range of iodide – iodate speciation in atmospheric aerosol. Therefore, we also investigate the effects of the recently suggested reaction of HOI with dissolved organic matter to produce iodide. If this reaction is fast enough to compete with the inorganic mechanism, it would not only directly lead to enhanced iodide concentrations but, indirectly via speed-up of the inorganic iodate reduction cycles, also to a decrease in iodate concentrations. Hence, according to our model studies, organic iodine chemistry, combined with inorganic reaction cycles, is able to reproduce observations. The presented chemistry cycles are highly dependent on pH and thus offer an explanation for the large observed variability of the iodide – iodate speciation in atmospheric aerosol.

  6. Thermodynamic Modeling of Atmospheric Aerosols: Predicting Water Content and Solute Activities

    Science.gov (United States)

    Dutcher, C. S.; Ge, X.; Wexler, A. S.; Clegg, S.

    2012-12-01

    Accurate predictions of water and solute activities in atmospheric aerosols to very low equilibrium relative humidities (RH) are central to predications of aerosol size, optical properties and cloud formation. A powerful method has been recently developed (Dutcher et al. JPC C, 2011, 2012) for capturing the thermodynamic properties of multicomponent aerosols at low and intermediate levels of RH (adjustable model parameters, allowing for a unified thermodynamic treatment for a wider range of atmospheric systems. The long-range interactions due to electrostatic screenings of ions in solution are included through a mole fraction based Pitzer-Debye-Hückel (PDH) term. Equations for the Gibbs free energy, solvent and solute activity, and solute concentration are derived, yielding remarkable agreement of the solute concentration and osmotic coefficients for solutions over the entire 0 to 100% RH range. The number of adjustable model parameters is reduced by relating the values of the energy of adsorption to each hydration layer to known short-range Coulombic electrostatic relationships. The effect of the PDH long-range and Coulombic short-range electrostatics on the mixing relationship is explored and new insights into the molecular relationships within atmospheric aerosols is discussed. Fields beyond atmospheric aerosol science, including geological and ocean solution thermodynamics, may benefit from the models developed in this work.

  7. The electrical charging of inactive aerosols in high ionised atmosphere, the electrical charging of artificial beta radioactive aerosols; Le processus de charge electrique: des aerosols non radioactifs en milieu fortement ionise, des aerosols radioactifs artificiels emetteurs beta

    Energy Technology Data Exchange (ETDEWEB)

    Gensdarmes, F

    2000-07-01

    The electrical properties of aerosols greatly influence their transport and deposition in a containment. In a bipolar ionic atmosphere, a neutral electric charge on aerosols is commonly assumed. However, many studies report a different charge distribution in some situations, like highly ionised atmosphere or in the case of radioactive aerosols. Such situations could arise from a hypothetical accident in a nuclear power plant. Within the framework of safety studies which are carried out at IPSN, our aims were the study of electrical properties of aerosols in highly ionised atmosphere, and the study of artificial radioactive aerosols, in order to suggest experimental validation of available theories. For this purpose, we designed an experimental device that allows us to measure non-radioactive aerosol charge distribution under high gamma irradiation, up to 10{sup 4} Gy/h. With our experimental device we also studied the properties of small ions in the medium. Our results show a variation of the charge distribution in highly ionised atmosphere. The charge increases with the dose of gamma ray. We have related this variation with the one of the small ions in the gases, according to theoretical prediction. However, the model overestimates slightly our experimental results. In the case of the radioactive aerosols, we have designed an original experimental device, which allows us to study the charge distribution of a {sup 137}Cs aerosol. Our results show that the electric charging of such aerosols is strongly dependent on evolution parameters in a containment. So, our results underline a great enhancement of self-charging of particles which are sampled in a confined medium. Our results are qualitatively in agreement with the theoretical model; nevertheless the latter underestimates appreciably the self-charging, owing to the fact that wall effects are not taken into account. (author)

  8. The Formation of Hydrochloric Acid Aerosol from the Interaction of the Space Shuttle Rocket Exhaust with the Atmosphere

    Science.gov (United States)

    Rhein, R. A.

    1973-01-01

    A description is given of conditions of atmospheric temperature and relative humidity under which hydrochloric acid aerosol is expected upon interaction of the proposed space shuttle rocket exhaust products with the atmosphere.

  9. Optical and microphysical properties of atmospheric aerosols in Moldova

    Science.gov (United States)

    Aculinin, Alexandr; Smicov, Vladimir

    2010-05-01

    Measurements of aerosol properties in Kishinev, Moldova are being carried out within the framework of the international AERONET program managed by NASA/GSFC since 1999. Direct solar and sky diffuse radiances are measured by using of sunphotometer Cimel-318. Aerosol optical properties are retrieved from measured radiances by using of smart computational procedures developed by the AERONET's team. The instrument is situated at the ground-based solar radiation monitoring station giving the opportunity to make simultaneous spectral (win sunphotometer) and broadband (with the set of sensors from radiometric complex) solar radiation. Detailed description of the station and investigations in progress can be found at the http://arg.phys.asm.md. Ground station is placed in an urban environment of Kishinev city (47.00N; 28.56E; 205 m a.s.l). Summary of aerosol optical and microphysical properties retrieved from direct solar and diffuse sky radiance observations at Moldova site from September 1999 to June 2009 are presented below. Number of measurements (total): 1695 Number of measurements (for ?o, n, k): 223 Range of aerosol optical depth (AOD) @440 nm: 0.03 =0.25 Range of Ångström parameter : 0.14 (440/670/870/1020): 0.93/0.92/0.90/0.89 ±0.04 Parameters of volume particle size distribution function: (fine mode) volume median radius r v,f , μm: 0.17 ± 0.06 particle volume concentration Cv,f, μm3/μm2: 0.04 ± 0.03 (coarse mode) volume median radius rv,c , μm: 3.08 ± 0.64 particle volume concentration Cv,c, μm3/μm2: 0.03 ± 0.03 Climatic norms of AOD@500 nm and Ångström parameter at the site of observation are equal to 0.21 ± 0.06 and 1.45 ± 0.14, respectively. The aerosol type in Moldova may be considered as 'urban-industrial and mixed' in accordance with the classification of aerosol type models systematized and developed by AERONET team (O.Dubovik et al., 2002, J. Atmosph. Sci., 59, 590-608) on the basis of datasets acquired from worldwide observations at the

  10. Dependence of atmospheric refractive index structure parameter (Cn2) on the residence time and vertical distribution of aerosols.

    Science.gov (United States)

    Anand, N; Satheesh, S K; Krishna Moorthy, K

    2017-07-15

    Effects of absorbing atmospheric aerosols in modulating the tropospheric refractive index structure parameter (Cn2) are estimated using high resolution radiosonde and multi-satellite data along with a radiative transfer model. We report the influence of variations in residence time and vertical distribution of aerosols in modulating Cn2 and why the aerosol induced atmospheric heating needs to be considered while estimating a free space optical communication link budget. The results show that performance of the link is seriously affected if large concentrations of absorbing aerosols reside for a long time in the atmospheric path.

  11. Volatile properties of atmospheric aerosols during nucleation events at Pune, India

    Science.gov (United States)

    Murugavel, P.; Chate, D. M.

    2011-06-01

    Continuous measurements of aerosol size distributions in the mid-point diameter range 20.5-500 nm were made from October 2005 to March 2006 at Pune (18°32'N, 73°51'E), India using Scanning Mobility Particle Sizer (SMPS). Volatilities of atmospheric aerosols were also measured at 40°, 125°, 175°, 300° and 350°C temperatures with Thermodenuder-SMPS coupled system to determine aerosol volatile fractions. Aerosols in nucleated, CCN and accumulated modes are characterized from the measured percentage of particles volatized at 40°, 125°, 175°, 300° and 350°C temperatures. Averaged monthly aerosol concentration is at its maximum in November and gradually decreases to its minimum at the end of March. The diurnal variations of aerosol concentrations gradually decrease in the night and in early morning hours (0400-0800 hr). However, concentration attains minimum in its variations in the noon (1400-1600 hr) due to higher ventilation factor (product of mixing height and wind speed). The half an hour averaged diurnal variation of aerosol number concentration shows about 5 to 10-fold increase despite the ventilation factor at higher side before 1200 hr. This sudden increase in aerosol concentrations is linked with prevailing conditions for nucleation bursts. The measurement of volatile fraction of ambient aerosols reveals that there are large number of highly volatile particles in the Aitken mode in the morning hours and these volatile fractions of aerosols at temperatures <150°C are of ammonium chloride and ammonium sulfate, acetic and formic acids.

  12. Effects of continental anthropogenic sources on organic aerosols in the coastal atmosphere of East China.

    Science.gov (United States)

    Shang, Dongjie; Hu, Min; Guo, Qingfeng; Zou, Qi; Zheng, Jing; Guo, Song

    2017-10-01

    Although organic compounds in marine atmospheric aerosols have significant effects on climate and marine ecosystems, they have rarely been studied, especially in the coastal regions of East China. To assess the origins of the organic aerosols in the East China coastal atmosphere, PM 2.5 samples were collected from the atmospheres of the Yellow Sea, the East China Sea, and Changdao Island during the CAPTAIN (Campaign of Air PolluTion At INshore Areas of Eastern China) field campaign in the spring of 2011. The marine atmospheric aerosol samples that were collected were grouped based on the backward trajectories of their air masses. The organic carbon concentrations in the PM 2.5 samples from the marine and Changdao Island atmospheres were 5.5 ± 3.1 μgC/m 3 and 6.9 ± 2.4 μgC/m 3 , respectively, which is higher than in other coastal water atmospheres. The concentration of polycyclic aromatic hydrocarbons (PAHs) in the marine atmospheric PM 2.5 samples was 17.0 ± 20.2 ng/m 3 , indicating significant continental anthropogenic influences. The influences of fossil fuels and biomass burning on the composition of organic aerosols in the coastal atmosphere of East China were found to be highly dependent on the origins of the air masses. Diesel combustion had a strong impact on air masses from the Yangtze River Delta (YRD), and gasoline emissions had a more significant impact on the "North China" marine atmospheric samples. The "Northeast China" marine atmospheric samples were most impacted by biomass burning. Coal combustion contributed significantly to the compositions of all of the atmospheric samples. The proportions of secondary compounds increased as samples aged in the marine atmosphere indicating that photochemical oxidation occured during transport. Our results quantified ecosystem effects on marine atmospheric aerosols and highlighted the uncertainties that arise when modeling marine atmospheric PM 2.5 without considering high spatial resolution source

  13. Significant Atmospheric Aerosol Pollution Caused by World Food Cultivation

    Science.gov (United States)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2016-01-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  14. Significant atmospheric aerosol pollution caused by world food cultivation

    Science.gov (United States)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2017-04-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to it s sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  15. Atmospheric Aqueous Aerosol Surface Tensions: Isotherm-Based Modeling and Biphasic Microfluidic Measurements.

    Science.gov (United States)

    Boyer, Hallie C; Dutcher, Cari S

    2017-06-29

    Surface properties of atmospheric aerosol particles are crucial for accurate assessments of the fates of liquid particles in the atmosphere. Surface tension directly influences predictions of particle activation to clouds, as well as indirectly acting as a proxy for chemical surface partitioning. Challenges to accounting for surface effects arise from surface tension dependence on solution concentration and the presence of complex aqueous mixtures in aerosols, including both surface-active organic solutes and inorganic electrolytes. Also, the interface itself is varied, in that it may be a liquid-vapor interface, as in the surface of an aerosol particle with ambient air, or a liquid-liquid interface between two immiscible liquids, as in the interior surfaces that exist in multiphase particles. In this Feature Article, we highlight our previous work entailing thermodynamic modeling of liquid-vapor surfaces to predict surface tension and microscopic examinations of liquid-liquid interfacial phenomena to measure interfacial tension using biphasic microscale flows. New results are presented for binary aqueous organic acids and their ternary solutions with ammonium sulfate. Ultimately, improved understanding of aerosol particle surfaces would enhance treatment of aerosol particle-to-cloud activation states and aerosol effects on climate.

  16. Atmospheric aerosol in an urban area: Comparison of measurement instruments and methodologies and pulmonary deposition assessment; Aerosol atmosferico in area urbanae di misura e valutazione di deposizione polmonare

    Energy Technology Data Exchange (ETDEWEB)

    Berico, M.; Luciani, A.; Formignani, M. [ENEA, Centro Ricerche Bologna (Italy). Dip. Ambiente

    1996-07-01

    In March 1995 a measurement campaign of atmospheric aerosol in the Bologna urban area (Italy) was carried out. A transportable laboratory, set up by ENEA (Italian national Agency for New Technologies, Energy and the Environment) Environmental Department (Bologna), was utilized with instruments for measurement of atmospheric aerosol and meteorological parameters. The aim of this campaign was of dual purpose: to characterize aerosol in urban area and to compare different instruments and methodologies of measurements. Mass concentrations measurements, evaluated on a 23-hour period with total filter, PM10 dichotomous sampler and low pressure impactor (LPI Berner), have provided information respectively about total suspended particles, respirable fraction and granulometric parameters of aerosol. Eight meteorologic parameters, number concentration of submicromic fraction of aerosol and mass concentration of micromic fraction have been continually measured. Then, in a daytime period, several number granulometries of atmospheric aerosol have also been estimated by means of diffusion battery system. Results related to different measurement methodologies and granulometric characteristics of aerosol are presented here. Pulmonary deposition of atmospheric aerosol is finally calculated, using granulometries provided by LPI Brener and ICRP 66 human respiratory tract model.

  17. Atmospheric aerosol deposition influences marine microbial communities in oligotrophic surface waters of the western Pacific Ocean

    Science.gov (United States)

    Maki, Teruya; Ishikawa, Akira; Mastunaga, Tomoki; Pointing, Stephen B.; Saito, Yuuki; Kasai, Tomoaki; Watanabe, Koichi; Aoki, Kazuma; Horiuchi, Amane; Lee, Kevin C.; Hasegawa, Hiroshi; Iwasaka, Yasunobu

    2016-12-01

    Atmospheric aerosols contain particulates that are deposited to oceanic surface waters. These can represent a major source of nutrients, trace metals, and organic compounds for the marine environment. The Japan Sea and the western Pacific Ocean are particularly affected by aerosols due to the transport of desert dust and industrially derived particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) from continental Asia. We hypothesized that supplementing seawater with aerosol particulates would lead to measurable changes in surface water nutrient composition as well as shifts in the marine microbial community. Shipboard experiments in the Pacific Ocean involved the recovery of oligotrophic oceanic surface water and subsequent supplementation with aerosol particulates obtained from the nearby coastal mountains, to simulate marine particulate input in this region. Initial increases in nitrates due to the addition of aerosol particulates were followed by a decrease correlated with the increase in phytoplankton biomass, which was composed largely of Bacillariophyta (diatoms), including Pseudo-nitzschia and Chaetoceros species. This shift was accompanied by changes in the bacterial community, with apparent increases in the relative abundance of heterotrophic Rhodobacteraceae and Colwelliaceae in aerosol particulate treated seawater. Our findings provide empirical evidence revealing the impact of aerosol particulates on oceanic surface water microbiology by alleviating nitrogen limitation in the organisms.

  18. Field observations linking organic carbon content to optical properties in atmospheric aerosols

    Science.gov (United States)

    Flowers, B. A.; Dubey, M. K.; Mazzoleni, C.; Zelenyuk, A.; Schauer, J. J.

    2009-12-01

    Ground and airborne measurements of aerosol optical properties and chemical composition are reported from the fall 2008 Cheju Atmospheric Brown Cloud Plume-Asian Monsoon Experiment (CAPMEX; www-ramanathan.ucsd.edu/capmex.html) and spring 2007 Indirect and Semi-direct Aerosol Campaign (ISDAC; acrf-campaign.arm.gov/isdac/) field campaigns. Correlation between increased short wavelength absorption, measured by a 3-laser photoacoustic soot spectrometer (LANL), and increased brown carbon content, measured by single particle laser ablation aerosol mass spectrometry (PNNL) and filter based thermo-optical methods (UW), are observed in both Asian continental outflow and Arctic Haze aerosols. In both campaigns, we observe significant darkening in single scatter albedo at 405 nm (down to ~0.7) relative to 532 and 781 nm for aerosols with larger brown carbon (soot + organic) mass fractions. We investigate the nature of optical property/composition correlations and their implications for radiative forcing; determination of the wavelength dependence of mass absorption cross sections for brown carbon aerosols; and the utility of diagnosing aerosol sources using the wavelength dependence of their optical properties.

  19. Inverse atmospheric radiative transfer problems - A nonlinear minimization search method of solution. [aerosol pollution monitoring

    Science.gov (United States)

    Fymat, A. L.

    1976-01-01

    The paper studies the inversion of the radiative transfer equation describing the interaction of electromagnetic radiation with atmospheric aerosols. The interaction can be considered as the propagation in the aerosol medium of two light beams: the direct beam in the line-of-sight attenuated by absorption and scattering, and the diffuse beam arising from scattering into the viewing direction, which propagates more or less in random fashion. The latter beam has single scattering and multiple scattering contributions. In the former case and for single scattering, the problem is reducible to first-kind Fredholm equations, while for multiple scattering it is necessary to invert partial integrodifferential equations. A nonlinear minimization search method, applicable to the solution of both types of problems has been developed, and is applied here to the problem of monitoring aerosol pollution, namely the complex refractive index and size distribution of aerosol particles.

  20. The Impact of Biogenic and Anthropogenic Atmospheric Aerosol on Climate in Egypt

    Science.gov (United States)

    Ibrahim, A. I.; Zakey, A.; Steiner, A. L.; Shokr, M. E.; El-Raey, M.; Ahmed, Y.; Al-Hadidi, A.; Zakey, A.

    2014-12-01

    Aerosols are indicators of air quality as they reduce visibility and adversely affect public health. Aerosol optical depth (AOD) is a measure of the radiation extinction due to interaction of radiation with aerosol particles in the atmosphere. Using this optical measure of atmospheric aerosols we explore the seasonal and annual patterns of aerosols from both anthropogenic and biogenic sources over Egypt. Here, we use an integrated environment-climate-aerosol model in conjunction with inversion technique to identify the aerosol particle size distribution over different locations in Egypt. The online-integrated Environment-Climate-Aerosol model (EnvClimA), which is based on the International Center for Theoretical Physics Regional Climate Model (ICTP-RegCM), is used to study the emission of different aerosols and their impact on climate parameters for a long-term base line simulation run over Egypt and North Africa. The global emission inventory is downscaled and remapping them over Egypt using local factors such as population, traffic and industrial activities to identify the sources of anthropogenic and biogenic emission from local emission over Egypt. The results indicated that the dominant natural aerosols over Egypt are dust emissions that frequently occur during the transitional seasons (Spring and Autumn). From the local observation we identify the number of dust and sand storm occurrences over Egypt. The Multiangle Imaging SpectroRadiometer (MISR) is used to identify the optical characterizations of different types of aerosols over Egypt. Modeled aerosol optical depth and MISR observed (at 555 nm) are compared from March 2000 through November 2013. The results identify that the MISR AOD captures the maximum peaks of AOD in March/April that coincide with the Khamasin dust storms. However, peaks in May are either due to photochemical reactions or anthropogenic activities. Note: This presentation is for a Partnerships for Enhanced Engagement in Research (PEER

  1. Improvements of organic aerosol representations and their effects in large-scale atmospheric models

    Directory of Open Access Journals (Sweden)

    H. Tost

    2012-09-01

    Full Text Available Organics dominate the composition of the atmospheric aerosol, especially in the fine mode, influencing some of its characteristics such as the hygroscopicity, which is of climatic relevance for the Earth system. This study targets an improvement in the description of organic aerosols suitable for large-scale modelling, making use of recent developments based on laboratory and field measurements. In addition to the organic mass and particle number distribution, the proposed method keeps track of the oxidation state of the aerosol based on the OH exposure time, describing some of its chemical characteristics. This study presents the application of the method in a global chemistry climate model, investigates the sensitivity to process formulations and emission assignments, provides a comparison with observations and analyses the climate impact.

    Even though the organic aerosol mass distribution is hardly affected by the new formulation, it shows impacts (regionally of the order of 10 % to 20 % on parameters directly influencing climate via the direct and indirect aerosol effects. Furthermore, the global distribution of the organic O:C ratio is analysed in detail, leading to different regimes in the oxidation state: low O:C ratios over the tropical continents due to small OH concentrations caused by OH depletion in chemical reactions, and enhanced oxidation states over the tropical oceans based on less OH scavengers and at high altitudes due to longer atmospheric residence time. Due to the relation between O:C ratio and the aerosol hygroscopicity the ageing results in a more physically and chemically consistent description of aerosol water uptake by the organic aerosol. In comparison with observations reasonable agreement for the O:C ratio within the limits of a global model of the simulations is achieved.

  2. Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol.

    Science.gov (United States)

    Kroll, Jesse H; Donahue, Neil M; Jimenez, Jose L; Kessler, Sean H; Canagaratna, Manjula R; Wilson, Kevin R; Altieri, Katye E; Mazzoleni, Lynn R; Wozniak, Andrew S; Bluhm, Hendrik; Mysak, Erin R; Smith, Jared D; Kolb, Charles E; Worsnop, Douglas R

    2011-02-01

    A detailed understanding of the sources, transformations and fates of organic species in the environment is crucial because of the central roles that they play in human health, biogeochemical cycles and the Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here, we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state, a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of the average carbon oxidation state, using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number.

  3. Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Massachusetts Institute of Technology; Kroll, Jesse H.; Donahue, Neil M.; Jimenez, Jose L.; Kessler, Sean H.; Canagaratna, Manjula R.; Wilson, Kevin R.; Altieri, Katye E.; Mazzoleni, Lynn R.; Wozniak, Andrew S.; Bluhm, Hendrik; Mysak, Erin R.; Smith, Jared D.; Kolb, Charles E.; Worsnop, Douglas R.

    2010-11-05

    A detailed understanding of the sources, transformations, and fates of organic species in the environment is crucial because of the central roles that organics play in human health, biogeochemical cycles, and Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state (OSC), a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of OSC , using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number (nC).

  4. Aerosol Constraints on the Atmosphere of the Hot Saturn-mass Planet WASP-49b

    Science.gov (United States)

    Cubillos, Patricio E.; Fossati, Luca; Erkaev, Nikolai V.; Malik, Matej; Tokano, Tetsuya; Lendl, Monika; Johnstone, Colin P.; Lammer, Helmut; Wyttenbach, Aurélien

    2017-11-01

    The strong, nearly wavelength-independent absorption cross section of aerosols produces featureless exoplanet transmission spectra, limiting our ability to characterize their atmospheres. Here, we show that even in the presence of featureless spectra, we can still characterize certain atmospheric properties. Specifically, we constrain the upper and lower pressure boundaries of aerosol layers, and present plausible composition candidates. We study the case of the bloated Saturn-mass planet WASP-49 b, where near-infrared observations reveal a flat transmission spectrum between 0.7 and 1.0 μm. First, we use a hydrodynamic upper-atmosphere code to estimate the pressure reached by the ionizing stellar high-energy photons at {10}-8 bar, setting the upper pressure boundary where aerosols could exist. Then, we combine HELIOS and Pyrat Bay radiative-transfer models to constrain the temperature and photospheric pressure of atmospheric aerosols, in a Bayesian framework. For WASP-49 b, we constrain the transmission photosphere (hence, the aerosol deck boundaries) to pressures above {10}-5 bar (100× solar metallicity), {10}-4 bar (solar), and {10}-3 bar (0.1× solar) as the lower boundary, and below {10}-7 bar as the upper boundary. Lastly, we compare condensation curves of aerosol compounds with the planet’s pressure-temperature profile to identify plausible condensates responsible for the absorption. Under these circumstances, we find these candidates: {{Na}}2{{S}} (at 100× solar metallicity); Cr and MnS (at solar and 0.1× solar) and forsterite, enstatite, and alabandite (at 0.1× solar).

  5. Impacts of Aerosol Shortwave Radiation Absorption on the Dynamics of an Idealized Convective Atmospheric Boundary Layer

    NARCIS (Netherlands)

    Wilde Barbaro, E.; Vilà-Guerau de Arellano, J.; Krol, M.C.; Holtslag, A.A.M.

    2013-01-01

    We investigated the impact of aerosol heat absorption on convective atmospheric boundary-layer (CBL) dynamics. Numerical experiments using a large-eddy simulation model enabled us to study the changes in the structure of a dry and shearless CBL in depthequilibrium for different vertical profiles of

  6. Application of a commercial lidar-ceilometer to studies of aerosols in the atmospheric boundary layer

    CSIR Research Space (South Africa)

    Ramkilowan, A

    2015-09-01

    Full Text Available has therefore become of great interest. CSIR/DPSS has acquired and deployed a Vaisala CL51 ceilometer chiefly for the purpose of investigating the vertical distribution of aerosols in the Atmospheric Boundary Layer (ABL) and cloud base height...

  7. Conversion function between the Linke turbidity and the atmospheric water vapor and aerosol content

    OpenAIRE

    Ineichen, Pierre

    2008-01-01

    This technical note presents a conversion function between the widely used Linke turbidity coefficient TL, the atmospheric water vapor and urban aerosol content. It takes into account the altitude of the application site. The function is based on radiative transfer calculations and validated with the help of an independent clear sky model. Its precision is around 0.12 units of TL.

  8. Semicontinuous automated measurement of organic carbon in atmospheric aerosol samples.

    Science.gov (United States)

    Lu, Chao; Rashinkar, Shilpa M; Dasgupta, Purnendu K

    2010-02-15

    A fully automated measurement system for ambient aerosol organic carbon, capable of unattended operation over extended periods, is described. Particles are collected in a cyclone with water as the collection medium. The collected sample is periodically aspirated by a syringe pump into a holding loop and then delivered to a wet oxidation reactor (WOR). Acid is added, and the WOR is purged to measure dissolved CO(2) or inorganic carbonates (IC) as evolved CO(2). The IC background can often be small and sufficiently constant to be corrected for, without separate measurement, by a blank subtraction. The organic material is now oxidized stepwise or in one step to CO(2). The one-step oxidation involves UV-persulfate treatment in the presence of ozone. This treatment converts organic carbon (OC) to CO(2), but elemental carbon is not oxidized. The CO(2) is continuously purged from solution and collected by two sequential miniature diffusion scrubbers (DSs), a short DS preceding a longer one. Each DS consists of a LiOH-filled porous hydrophobic membrane tube with terminal stainless steel tubes that function as conductance-sensing electrodes. As CO(2) is collected by the LiOH-filled DSs, hydroxide is converted into carbonate and the resulting decrease in conductivity is monitored. The simultaneous use of the dual short and long DS units bearing different concentrations of LiOH permits both good sensitivity and a large dynamic range. The limit of detection (LOD, S/N = 3) is approximately 140 ng of C. With a typical sampling period of 30 min at a sampling rate of 30 L/min, this corresponds to an LOD of 160 ng/m(3). The approach also provides information on the ease of oxidation of the carbonaceous aerosol and hence the nature of the carbon contained therein. Ambient aerosol organic carbon data are presented.

  9. Optimal eigenanalysis for the treatment of aerosols in the retrieval of atmospheric composition from transmission measurements.

    Science.gov (United States)

    Timofeyev, Yuriy M; Polyakov, Alexander V; Steele, Helen M; Newchurch, Michael J

    2003-05-20

    The separation of the individual contributions of aerosol and gases to the total attenuation of radiation through the atmosphere has been the subject of much scientific investigation since remote sensing experiments first began. We describe a new scheme to account for the spectral variation of the aerosol extinction in the inversion of transmission data from occultation measurements. Because the spectral variation of the aerosol extinction is generally unknown,the inversion problem is underdetermined and cannot be solved without a reduction in the number of unknowns in the set of equations used to describe the attenuation at each wavelength. This reduction can be accomplished by a variety of methods, including use of a priori information, the parameterization of the aerosol spectral attenuation, and the specification of the form of the aerosol size distribution. We have developed and implemented a parameterization scheme based on existing empirical and modeled information about the microphysical properties of aerosols. This scheme employs the eigenvectors from an extensive set of simulations to parameterize the aerosol extinction coefficient for incorporation into the inversion algorithm. We examine the accuracy of our method using data sets containing over 24,000 extinction spectra and compare it with that of another scheme that is currently implemented in the Polar Ozone and Aerosol Measurement (POAM) satellite experiment. In simulations using 80 wavelengths in the UV-visible-near-IR spectral range of the Stratospheric Aerosol and Gas Experiment III (SAGE) instrument, we show that, for our optimal parameterization, errors below 1% are observed in 80% of cases, whereas only approximately 20% of all cases are as accurate as this in a quadratic parameterization employing the logarithm of the wavelength.

  10. The dynamic surface tension of atmospheric aerosol surfactants reveals new aspects of cloud activation

    Science.gov (United States)

    Nozière, Barbara; Baduel, Christine; Jaffrezo, Jean-Luc

    2014-01-01

    The activation of aerosol particles into cloud droplets in the Earth’s atmosphere is both a key process for the climate budget and a main source of uncertainty. Its investigation is facing major experimental challenges, as no technique can measure the main driving parameters, the Raoult’s term and surface tension, σ, for sub-micron atmospheric particles. In addition, the surfactant fraction of atmospheric aerosols could not be isolated until recently. Here we present the first dynamic investigation of the total surfactant fraction of atmospheric aerosols, evidencing adsorption barriers that limit their gradient (partitioning) in particles and should enhance their cloud-forming efficiency compared with current models. The results also show that the equilibration time of surfactants in sub-micron atmospheric particles should be beyond the detection of most on-line instruments. Such instrumental and theoretical shortcomings would be consistent with atmospheric and laboratory observations and could have limited the understanding of cloud activation until now. PMID:24566451

  11. Reformulating atmospheric aerosol thermodynamics and hygroscopic growth into fog, haze and clouds

    Directory of Open Access Journals (Sweden)

    S. Metzger

    2007-06-01

    Full Text Available Modeling atmospheric aerosol and cloud microphysics is rather complex, even if chemical and thermodynamical equilibrium is assumed. We show, however, that the thermodynamics can be considerably simplified by reformulating equilibrium to consistently include water, and transform laboratory-based concepts to atmospheric conditions. We generalize the thermodynamic principles that explain hydration and osmosis – merely based on solute solubilities – to explicitly account for the water mass consumed by hydration. As a result, in chemical and thermodynamical equilibrium the relative humidity (RH suffices to determine the saturation molality, including solute and solvent activities (and activity coefficients, since the water content is fixed by RH for a given aerosol concentration and type. As a consequence, gas/liquid/solid aerosol equilibrium partitioning can be solved analytically and non-iteratively. Our new concept enables an efficient and accurate calculation of the aerosol water mass and directly links the aerosol hygroscopic growth to fog, haze and cloud formation.

    We apply our new concept in the 3rd Equilibrium Simplified Aerosol Model (EQSAM3 for use in regional and global chemistry-transport and climate models. Its input is limited to the species' solubilities from which a newly introduced stoichiometric coefficient for water is derived. Analogously, we introduce effective stoichiometric coefficients for the solutes to account for complete or incomplete dissociation. We show that these coefficients can be assumed constant over the entire activity range and calculated for various inorganic, organic and non-electrolyte compounds, including alcohols, sugars and dissolved gases. EQSAM3 calculates the aerosol composition and gas/liquid/solid partitioning of mixed inorganic/organic multicomponent solutions and the associated water uptake for almost 100 major compounds. It explicitly accounts for particle hygroscopic growth by

  12. Ångström coefficient as an indicator of the atmospheric aerosol type for a well-mixed atmospheric boundary layer: Part 1: Model development

    Directory of Open Access Journals (Sweden)

    Jolanta Kuśmierczyk-Michulec

    2009-03-01

    Full Text Available The physical and optical properties of an atmospheric aerosol mixture depend on a number of factors. The relative humidity influences the size of hydroscopic particles and the effective radius of an aerosol mixture. In consequence, values of the aerosol extinction, the aerosol optical thickness and the Ångström coefficient are modified. A similar effect is observed when the aerosol composition changes. A higher content of small aerosol particles causes the effective radius of an aerosol mixture to decrease and the Ångström coefficient to increase. Both effects are analysed in this paper. The parameters of the size distribution and the type of components used to represent natural atmospheric aerosol mixtures are based on experimental data. The main components are sea-salts (SSA, anthropogenic salts (WS, e.g. NH4HSO4, NH4NO3, (NH42 SO4, organic carbon (OC and black carbon (BC. The aerosol optical thickness is modelled using the external mixing approach. The influence of relative humidity on the optical and physical properties of the following aerosol mixtures is investigated: (SSA & WS, (SSA & OC, (SSA & BC, (SSA, WS & OC and (WS, OC & BC. It is demonstrated that the Ängström coefficient can be used as a rough indicator of the aerosol type.

  13. Investigation of aerosol radiative forcing and atmosphere-ocean remote sensing in Northern Norway

    Science.gov (United States)

    Chen, Yi-Chun; Hamre, Børge; Stamnes, Snorre; Frette, Øyvind; Stamnes, Kunt; Stamnes, Jakob J.

    2013-04-01

    We examine aerosol optical properties and radiative forcing at Andenes, Northern Norway (69N, 16E, 379 m altitude) during a two-year period (2008-2010) using AERONET data, radiative transfer modelling (C-DISORT), and Mie-scattering computations. We show that the mean value of the aerosol optical thickness at 500 nm derived from AERONET measurements is close to that obtained from Mie-scattering computations with input of aerosol size distribution and refractive index as derived from AERONET measurements. Also, different models for the ground reflectance used as input to the radiative transfer computations are shown to have little impact on the aerosol radiative forcing both at the top and bottom of the atmosphere. The coupled atmosphere-surface system accounted for by C-DISORT is suitable for radiative transfer calculations over open ocean and coastal water areas, and we discuss how it can be used to make simultaneous retrieval of aerosol and marine parameters from ocean colour data.

  14. Spatial and Temporal Variations of Atmospheric Aerosol in Osaka

    Directory of Open Access Journals (Sweden)

    Sonoyo Mukai

    2013-05-01

    Full Text Available It is well known that the aerosol distribution in Asia is complex due to both the increasing emissions of the anthropogenic aerosols associated with economic growth and the behavior of natural dusts. Therefore, detailed observations of atmospheric particles in Asian urban cities are important. In this work, we focus on the spatial and temporal variations of atmospheric particles around Higashi-Osaka in Japan. Higashi-Osaka is located in the eastern part of Osaka, the second-largest city in Japan, and is famous for small- and medium-sized manufacturing enterprises. For this study, we placed various ground measurement devices around the Higashi-Osaka campus of Kinki University including a Cimel sunphotometer supported by NASA/AERONET (Aerosol robotics network, suspended particulate matter (SPM sampler and LIDAR (light detection and ranging. Individual particle analyses with a SEM (scanning electron microscope/EDX (energy-dispersive X-ray analyzer show the temporal variations of particle properties, such as size, shape and components, during a dust event on 21 March 2010. The simultaneous measurement using a portable sun photometer with AERONET was conducted from April to November 2011. A comparison of the data at each site and the combination of the observed LIDAR data and model simulations indicate the difference in the transportation processes between dust and anthropogenic particles. We suppose this difference is attributed to the differences in the vertical aerosol profiles, where one aerosol is transported over Mount Ikoma and the other is blocked by it.

  15. Oxidation of c60 aerosols by atmospherically relevant levels of o3.

    Science.gov (United States)

    Tiwari, Andrea J; Morris, John R; Vejerano, Eric P; Hochella, Michael F; Marr, Linsey C

    2014-01-01

    Atmospheric processing of carbonaceous nanoparticles (CNPs) may play an important role in determining their fate and environmental impacts. This work investigates the reaction between aerosolized C60 and atmospherically relevant mixing ratios of O3 at differing levels of humidity. Results indicate that C60 is oxidized by O3 and forms a variety of oxygen-containing functional groups on the aerosol surface, including C60O, C60O2, and C60O3. The pseudo-first-order reaction rate between C60 and O3 ranges from 9 × 10(-6) to 2 × 10(-5) s(-1). The reaction is likely to be limited to the aerosol surface. Exposure to O3 increases the oxidative stress exerted by the C60 aerosols as measured by the dichlorofluorescein acellular assay but not by the uric acid, ascorbic acid, glutathione, or dithiothreitol assays. The initial prevalence of C60O and C60O2 as intermediate products is enhanced at higher humidity, as is the surface oxygen content of the aerosols. These results show that C60 can be oxidized when exposed to O3 under ambient conditions, such as those found in environmental, laboratory, and industrial settings.

  16. Atmospheric aerosols in Amazonia and land use change: from natural biogenic to biomass burning conditions.

    Science.gov (United States)

    Artaxo, Paulo; Rizzo, Luciana V; Brito, Joel F; Barbosa, Henrique M J; Arana, Andrea; Sena, Elisa T; Cirino, Glauber G; Bastos, Wanderlei; Martin, Scot T; Andreae, Meinrat O

    2013-01-01

    In the wet season, a large portion of the Amazon region constitutes one of the most pristine continental areas, with very low concentrations of atmospheric trace gases and aerosol particles. However, land use change modifies the biosphere-atmosphere interactions in such a way that key processes that maintain the functioning of Amazonia are substantially altered. This study presents a comparison between aerosol properties observed at a preserved forest site in Central Amazonia (TT34 North of Manaus) and at a heavily biomass burning impacted site in south-western Amazonia (PVH, close to Porto Velho). Amazonian aerosols were characterized in detail, including aerosol size distributions, aerosol light absorption and scattering, optical depth and aerosol inorganic and organic composition, among other properties. The central Amazonia site (TT34) showed low aerosol concentrations (PM2.5 of 1.3 +/- 0.7 microg m(-3) and 3.4 +/- 2.0 microg m(-3) in the wet and dry seasons, respectively), with a median particle number concentration of 220 cm(-3) in the wet season and 2200 cm(-3) in the dry season. At the impacted site (PVH), aerosol loadings were one order of magnitude higher (PM2.5 of 10.2 +/- 9.0 microg m(-3) and 33.0 +/- 36.0 microg m(-3) in the wet and dry seasons, respectively). The aerosol number concentration at the impacted site ranged from 680 cm(-3) in the wet season up to 20 000 cm(-3) in the dry season. An aerosol chemical speciation monitor (ACSM) was deployed in 2013 at both sites, and it shows that organic aerosol account to 81% to the non-refractory PM1 aerosol loading at TT34, while biomass burning aerosols at PVH shows a 93% content of organic particles. Three years of filter-based elemental composition measurements shows that sulphate at the impacted site decreases, on average, from 12% of PM2.5 mass during the wet season to 5% in the dry season. This result corroborates the ACSM finding that the biomass burning contributed overwhelmingly to the organic

  17. In Situ Single Particle Measurement of Atmospheric Aging of Carbonaceous Aerosols During CARES

    Science.gov (United States)

    Cahill, J. F.; Suski, K.; Hubbe, J.; Shilling, J.; Zaveri, R. A.; Springston, S. R.; Prather, K. A.

    2011-12-01

    Atmospheric aging of aerosols through photochemistry, heterogeneous reactions and aqueous processing can change their physical and chemical properties, impacting their gas uptake, radiative forcing, and activation of cloud nuclei. Understanding the timescale and magnitude of this aging process is essential for accurate aerosol-climate modeling and predictions. An aircraft aerosol time-of-flight mass spectrometer (A-ATOFMS) measured single particle mixing state during the Carbonaceous Aerosols and Radiative Effects Study (CARES) in the summer of 2010 over Sacramento, CA. On 6/23/10, flights in the morning and afternoon performed pseudo-Lagrangian sampling of the Sacramento urban plume. Carbonaceous particles from these flights were classified into 'aged' and 'fresh' classes based on their mixing state, with aged particles having more secondary species, such as nitrate and sulfate. In the morning flight, a clear decreasing trend in the ratio of fresh/aged particle types was seen as the flight progressed, whereas in the afternoon flight, the ratio was essentially constant. These data show that in the morning carbonaceous aerosols can become heavily oxidized in a few hours. Further analysis of particle mixing state and the timescale of carbonaceous aerosol aging will be presented

  18. The global impact of the transport sectors on atmospheric aerosol in 2030 – Part 2: Aviation

    Directory of Open Access Journals (Sweden)

    M. Righi

    2016-04-01

    Full Text Available We use the EMAC (ECHAM/MESSy Atmospheric Chemistry global climate–chemistry model coupled to the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications to simulate the impact of aviation emissions on global atmospheric aerosol and climate in 2030. Emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare our findings with the results of a previous study with the same model configuration focusing on year 2000 emissions. We also characterize the aviation results in the context of the other transport sectors presented in a companion paper. In spite of a relevant increase in aviation traffic volume and resulting emissions of aerosol (black carbon and aerosol precursor species (nitrogen oxides and sulfur dioxide, the aviation effect on particle mass concentration in 2030 remains quite negligible (on the order of a few ng m−3, about 1 order of magnitude less than the increase in concentration due to other emission sources. Due to the relatively small size of the aviation-induced aerosol, however, the increase in particle number concentration is significant in all scenarios (about 1000 cm−3, mostly affecting the northern mid-latitudes at typical flight altitudes (7–12 km. This largely contributes to the overall change in particle number concentration between 2000 and 2030, which also results in significant climate effects due to aerosol–cloud interactions. Aviation is the only transport sector for which a larger impact on the Earth's radiation budget is simulated in the future: the aviation-induced radiative forcing in 2030 is more than doubled with respect to the year 2000 value of −15 mW m−2 in all scenarios, with a maximum value of −63 mW m−2 simulated for RCP2.6.

  19. iSPEX: everybody can measure atmospheric aerosols with a smartphone spectropolarimeter

    Science.gov (United States)

    Snik, F.; Heikamp, S.; de Boer, J.; Keller, C. U.; van Harten, G.; Smit, J. M.; Rietjens, J. H. H.; Hasekamp, O.; Stam, D. M.; Volten, H.; iSPEX Team

    2012-04-01

    An increasing amount people carry a mobile phone with internet connection, camera and large computing power. iSPEX, a spectropolarimetric add-on with complementary app, instantly turns a smartphone into a scientific instrument to measure dust and other aerosols in our atmosphere. A measurement involves scanning the blue sky, which yields the angular behavior of the degree of linear polarization as a function of wavelength, which can unambiguously be interpreted in terms of size, shape and chemical composition of the aerosols in the sky directly above. The measurements are tagged with location and pointing information, and submitted to a central database where they will be interpreted and compiled into an aerosol map. Through crowdsourcing, many people will thus be able to contribute to a better assessment of health risks of particulate matter and of whether or not volcanic ash clouds are dangerous for air traffic. It can also contribute to the understanding of the relationship between atmospheric aerosols and climate change. We will give a live presentation of the first iSPEX prototype. Furthermore, we will present the design and the plans for producing the iSPEX add-on, app and website. We aim to distribute thousands of iSPEX units, such that a unique network of aerosol measurement equipment is created. Many people will thus contribute to the solution of several urgent social and scientific problems, and learn about the nature of light, remote sensing and the issues regarding atmospheric aerosols in the process. In particular we focus on school classes where smartphones are usually considered a nuisance, whereas now they can be a crucial part of various educational programs in science class.

  20. Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation

    CERN Document Server

    Kirkby, Jasper; Almeida, João; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Franchin, Alessandro; Gagné, Stéphanie; Ickes, Luisa; Kürten, Andreas; Kupc, Agnieszka; Metzger, Axel; Riccobono, Francesco; Rondo, Linda; Schobesberger, Siegfried; Tsagkogeorgas, Georgios; Wimmer, Daniela; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Downard, Andrew; Ehn, Mikael; Flagan, Richard C; Haider, Stefan; Hansel, Armin; Hauser, Daniel; Jud, Werner; Junninen, Heikki; Kreissl, Fabian; Kvashin, Alexander; Laaksonen, Ari; Lehtipalo, Katrianne; Lima, Jorge; Lovejoy, Edward R; Makhmutov, Vladimir; Mathot, Serge; Mikkilä, Jyri; Minginette, Pierre; Mogo, Sandra; Nieminen, Tuomo; Onnela, Antti; Pereira, Paulo; Petäjä, Tuukka; Schnitzhofer, Ralf; Seinfeld, John H; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Vanhanen, Joonas; Viisanen, Yrjo; Vrtala, Aron; Wagner, Paul E; Walther, Hansueli; Weingartner, Ernest; Wex, Heike; Winkler, Paul M; Carslaw, Kenneth S; Worsnop, Douglas R; Baltensperger, Urs; Kulmala, Markku

    2011-01-01

    Atmospheric aerosols exert an important influence on climate1 through their effects on stratiform cloud albedo and lifetime2 and the invigoration of convective storms3. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours4, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small5, 6. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia7. Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100–1,000-fold. Time-resolved molecular measurements reveal that n...

  1. Secondary organic aerosol from atmospheric photooxidation of indole

    Science.gov (United States)

    Montoya-Aguilera, Julia; Horne, Jeremy R.; Hinks, Mallory L.; Fleming, Lauren T.; Perraud, Véronique; Lin, Peng; Laskin, Alexander; Laskin, Julia; Dabdub, Donald; Nizkorodov, Sergey A.

    2017-09-01

    Indole is a heterocyclic compound emitted by various plant species under stressed conditions or during flowering events. The formation, optical properties, and chemical composition of secondary organic aerosol (SOA) formed by low-NOx photooxidation of indole were investigated. The SOA yield (1. 3 ± 0. 3) was estimated from measuring the particle mass concentration with a scanning mobility particle sizer (SMPS) and correcting it for wall loss effects. The high value of the SOA mass yield suggests that most oxidized indole products eventually end up in the particle phase. The SOA particles were collected on filters and analysed offline with UV-vis spectrophotometry to measure the mass absorption coefficient (MAC) of the bulk sample. The samples were visibly brown and had MAC values of ˜ 2 m2 g-1 at λ = 300 nm and ˜ 0. 5 m2 g-1 at λ = 400 nm, comparable to strongly absorbing brown carbon emitted from biomass burning. The chemical composition of SOA was examined with several mass spectrometry methods. Direct analysis in real-time mass spectrometry (DART-MS) and nanospray desorption electrospray high-resolution mass spectrometry (nano-DESI-HRMS) were both used to provide information about the overall distribution of SOA compounds. High-performance liquid chromatography, coupled to photodiode array spectrophotometry and high-resolution mass spectrometry (HPLC-PDA-HRMS), was used to identify chromophoric compounds that are responsible for the brown colour of SOA. Indole derivatives, such as tryptanthrin, indirubin, indigo dye, and indoxyl red, were found to contribute significantly to the visible absorption spectrum of indole SOA. The potential effect of indole SOA on air quality was explored with an airshed model, which found elevated concentrations of indole SOA during the afternoon hours contributing considerably to the total organic aerosol under selected scenarios. Because of its high MAC values, indole SOA can contribute to decreased visibility and poor air

  2. Aerosol model development for environmental monitoring in the coastal atmosphere surface layer

    Science.gov (United States)

    Kaloshin, Gennady A.; Matvienko, Gennady G.

    2007-06-01

    Extinction of radiation in the marine boundary layer is dominated by scattering and absorption due to atmospheric aerosol. It is known, that the extinction of optical radiation visible and near IR spectra in the marine surface layer is determined mainly by scattering and absorption atmospheric aerosol. It influences on a dependence of spectral transmission and extinction both natural, and artificial light that is of interest for a wide range of problems, in particular for radiating problems at studying laws of climate formation, and for lines of the applications connected to the forecast of a signal power in coastal conditions at an estimation of EO systems characteristics. This is important to optical retrievals from satellite, remote sensing at environmental monitoring, backscatter of light to space (including climate forcing), cloud properties etc. In unpolluted regions the greatest effects on near shore scattering extinction will be a result of sea-salt from breaking waves and variations in relative humidity. The role of breaking waves appears to be modulated by wind, tide, swell, wave spectra and coastal conditions. These influences will be superimposed upon aerosol generated by open ocean sea-salt aerosol that varies with wind speed. The focus of our study is the extinction and optical effects due to aerosol in a specific coastal region. This involves linking coastal physical properties to oceanic and meteorological parameters in order to develop predictive algorithms that describe 3-D aerosol structure and variability. The aerosol microphysical model of the marine and coastal atmosphere surface layer is considered. The model distinctive feature is parameterization of amplitude and width of the modes as functions of fetch and wind speed. In the paper the dN/dr behavior depending at change meteorological parameters, heights above sea level, fetch, wind speed and RH is show. On the basis of the developed model with usage of Mie theory for spheres the

  3. Current Research in Lidar Technology Used for the Remote Sensing of Atmospheric Aerosols.

    Science.gov (United States)

    Comerón, Adolfo; Muñoz-Porcar, Constantino; Rocadenbosch, Francesc; Rodríguez-Gómez, Alejandro; Sicard, Michaël

    2017-06-20

    Lidars are active optical remote sensing instruments with unique capabilities for atmospheric sounding. A manifold of atmospheric variables can be profiled using different types of lidar: concentration of species, wind speed, temperature, etc. Among them, measurement of the properties of aerosol particles, whose influence in many atmospheric processes is important but is still poorly stated, stands as one of the main fields of application of current lidar systems. This paper presents a review on fundamentals, technology, methodologies and state-of-the art of the lidar systems used to obtain aerosol information. Retrieval of structural (aerosol layers profiling), optical (backscatter and extinction coefficients) and microphysical (size, shape and type) properties requires however different levels of instrumental complexity; this general outlook is structured following a classification that attends these criteria. Thus, elastic systems (detection only of emitted frequencies), Raman systems (detection also of Raman frequency-shifted spectral lines), high spectral resolution lidars, systems with depolarization measurement capabilities and multi-wavelength instruments are described, and the fundamentals in which the retrieval of aerosol parameters is based is in each case detailed.

  4. Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing

    Science.gov (United States)

    Zhang, Renyi; Khalizov, Alexei F.; Pagels, Joakim; Zhang, Dan; Xue, Huaxin; McMurry, Peter H.

    2008-01-01

    The atmospheric effects of soot aerosols include interference with radiative transfer, visibility impairment, and alteration of cloud formation and are highly sensitive to the manner by which soot is internally mixed with other aerosol constituents. We present experimental studies to show that soot particles acquire a large mass fraction of sulfuric acid during atmospheric aging, considerably altering their properties. Soot particles exposed to subsaturated sulfuric acid vapor exhibit a marked change in morphology, characterized by a decreased mobility-based diameter but an increased fractal dimension and effective density. These particles experience large hygroscopic size and mass growth at subsaturated conditions (hygroscopic growth enhance the optical properties of soot aerosols, increasing scattering by ≈10-fold and absorption by nearly 2-fold at 80% relative humidity relative to fresh particles. In addition, condensation of sulfuric acid is shown to occur at a similar rate on ambient aerosols of various types of a given mobility size, regardless of their chemical compositions and microphysical structures. Representing an important mechanism of atmospheric aging, internal mixing of soot with sulfuric acid has profound implications on visibility, human health, and direct and indirect climate forcing. PMID:18645179

  5. Potentialities and Limits of ICESAT-2 Observation for Atmospheric Aerosol Investigation

    Directory of Open Access Journals (Sweden)

    Mona L.

    2016-01-01

    Full Text Available ICESat-2(Ice, Cloud, and land Elevation Satellite-2, slated for launch in 2017, will continue the important observations of ice-sheet elevation change, sea-ice freeboard, and vegetation canopy height begun by ICESat in 2003. Among the other potential applications, ICESat-2 could provide some information about atmospheric aerosol over Polar Regions thanks to the lidar instrument. In this context, it is essential to demonstrate the ICESat-2 capability of providing vertical profiles of the aerosol backscatter coefficient and to define its potentialities and limits. First results of this investigation are reported and will be presented at the conference.

  6. Atmospheric aerosol dispersion models and their applications to environmental risk assessment

    Directory of Open Access Journals (Sweden)

    Andrzej Mazur

    2014-03-01

    Full Text Available Introduction. Numerical models of dispersion of atmospheric pollutants are widely used to forecast the spread of contaminants in the air and to analyze the effects of this phenomenon. The aim of the study is to investigate the possibilities and the quality of diagnosis and prediction of atmospheric transport of aerosols in the air using the dispersion model of atmospheric pollutants, developed at the Institute of Meteorology and Water Management (IMWM in Warsaw. Material and methods. A model of the dispersion of atmospheric pollutants, linked with meteorological models in a diagnostic mode, was used to simulate the transport of the cloud of aerosols released during the crash near the town of Ożydiw (Ukraine and of volcanic ash – during the volcanic eruption of Eyjafjallajökull in Iceland. Results. Possible directions of dispersion of pollutants in the air and its concentration in the atmosphere and deposition to the soil were assessed. The analysis of temporal variability of concentrations of aerosols in the atmosphere confirmed that the model developed at IMWM is an effective tool for diagnosis of air quality in the area of Poland as well as for determination of exposure duration to the aerosol clouds for different weather scenarios. Conclusions. The results are a confirmation of the thesis, that because in the environmental risk assessment, an important element is not only current information on the level of pollution concentrations, but also the time of exposure to pollution and forecast of these elements, and consequently the predicted effects on man or the environment in general; so it is necessary to use forecasting tools, similar to presented application. The dispersion model described in the paper is an operational tool for description, analysis and forecasting of emergency situations in case of emissions of hazardous substances.

  7. Receptor modeling of atmospheric aerosols in Federal Capital ...

    African Journals Online (AJOL)

    The air quality of Abuja urban air shed was investigated with a view to establishing sources of pollution in the city. Forty samples of coarse atmospheric particulates (PM2.5-10) were collected at different categories of spatially distributed receptor locations; high (High-dra) and low (Low-dra) density residential, commercial ...

  8. Atmospheric aerosol formation and its growth during the cold ...

    Indian Academy of Sciences (India)

    mid-point diameter 13 nm and it is due to photo-chemical nucleation, coagulation and coalescence among nucleated clusters. The ratios of real to ... Atmospheric new particle formation processes contribute significantly to the global ..... It is desirable to quantify the influence of mole- cular mass and diffusivity of vapours of ...

  9. Impact of Atmospheric Aerosols on Solar Photovoltaic Electricity Generation in China

    Science.gov (United States)

    Li, X.; Mauzerall, D. L.; Wagner, F.; Peng, W.; Yang, J.

    2016-12-01

    Solar photovoltaic (PV) electricity generation has been expanding rapidly in China. Total capacity quintupled from 8 to 43 GW between 2012 and 2015. The Chinese government aims to increase total capacity to 400 GW, fulfilling about 10% of total electricity demand, by 2030. However, severe aerosol pollution in China reduces solar radiation reaching the surface by scattering and absorbing sunlight. We estimate the aerosol impact on solar PV electricity generation in China by examining the 12-year (2003-2014) average reduction in surface solar irradiance due to aerosols in the atmosphere. We apply the PVLIB-Python model, a PV performance tool, to calculate point-of-array irradiance (POAI), radiation incident on a PV panel of 220W and 1.7 m2, and the capacity factor (CF) every 3 hours from 2003-2014 at spatial resolution of 1° latitude x 1° longitude. For model input, we use (1) satellite-derived surface irradiance data from the NASA Clouds and the Earth's Radiant Energy System (CERES) -SYN1deg for POAI, and (2) observation-constrained reanalysis weather data (temperature and wind speed at 2 meters) from the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2) for system operating temperature that affects power output. We use the CERES irradiance data for multiple aerosol and cloud conditions to evaluate the impact of aerosols versus clouds on power output. Our results show that removing aerosols over Northern and Eastern China, the most polluted regions, increases annual average POAI on a fixed panel by up to 1.5 kWh/m2/day relative to current aerosol levels. This corresponds to an increase up to 35%. Over Northern China, aerosols, which influence POAI by up to 20%, are as important as clouds, and annually reduce POAI by about 25%. We evaluate the seasonal and diurnal variability of the impact and find that aerosols outperform clouds in reducing surface radiation in early morning and late afternoon during winter over both Northern and

  10. Laboratory Studies of Processing of Carbonaceous Aerosols by Atmospheric Oxidants/Hygroscopicity and CCN Activity of Secondary & Processed Primary Organic Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Ziemann, P.J.; Arey, J.; Atkinson, R.; Kreidenweis, S.M.; Petters, M.D.

    2012-06-13

    The atmosphere is composed of a complex mixture of gases and suspended microscopic aerosol particles. The ability of these particles to take up water (hygroscopicity) and to act as nuclei for cloud droplet formation significantly impacts aerosol light scattering and absorption, and cloud formation, thereby influencing air quality, visibility, and climate in important ways. A substantial, yet poorly characterized component of the atmospheric aerosol is organic matter. Its major sources are direct emissions from combustion processes, which are referred to as primary organic aerosol (POA), or in situ processes in which volatile organic compounds (VOCs) are oxidized in the atmosphere to low volatility reaction products that subsequent condense to form particles that are referred to as secondary organic aerosol (SOA). POA and VOCs are emitted to the atmosphere from both anthropogenic and natural (biogenic) sources. The overall goal of this experimental research project was to conduct laboratory studies under simulated atmospheric conditions to investigate the effects of the chemical composition of organic aerosol particles on their hygroscopicity and cloud condensation nucleation (CCN) activity, in order to develop quantitative relationships that could be used to more accurately incorporate aerosol-cloud interactions into regional and global atmospheric models. More specifically, the project aimed to determine the products, mechanisms, and rates of chemical reactions involved in the processing of organic aerosol particles by atmospheric oxidants and to investigate the relationships between the chemical composition of organic particles (as represented by molecule sizes and the specific functional groups that are present) and the hygroscopicity and CCN activity of oxidized POA and SOA formed from the oxidation of the major classes of anthropogenic and biogenic VOCs that are emitted to the atmosphere, as well as model hydrocarbons. The general approach for this project was

  11. External-beam PIGE for fluorine determination in atmospheric aerosol

    Science.gov (United States)

    Calastrini, F.; Del Carmine, P.; Lucarelli, F.; Mandò, P. A.; Prati, P.; Zucchiatti, A.

    1998-03-01

    Air pollution measurements have been performed at Montelupo, a town about 20 km west of Florence, characterised by the presence of a large number of ceramic and glass factories just inside the inhabited area. Both filters collecting aerosols during 24 h and streaker filters with 1-h resolution capability have been analysed, using external Particle Induced X-ray Emission (PIXE) and Proton-Induced Gamma-Ray Emission (PIGE) simultaneously. The best operating conditions for getting quantitative information from the PIGE analysis of fluorine in the external beam set-up have been investigated. The minimum detection limit for the concentration of fluorine in air is in the order of 10 ng/m 3. Some specific results concerning fluorine determination in both the 24 and 1-h resolution measurements are finally presented. While the average detected concentrations in air come out to be well below the air quality limits, time episodes of relatively higher concentration have been detected and thanks to the time correlation with the other elements the origin of these pollution episodes can be hypothesised with a good degree of confidence.

  12. Aerosol composition and microstructure in the smoky atmosphere of Moscow during the August 2010 extreme wildfires

    Science.gov (United States)

    Popovicheva, O. B.; Kistler, M.; Kireeva, E. D.; Persiantseva, N. M.; Timofeev, M. A.; Shoniya, N. K.; Kopeikin, V. M.

    2017-01-01

    This is a comprehensive study of the physicochemical characterization of multicomponent aerosols in the smoky atmosphere of Moscow during the extreme wildfires of August 2010 and against the background atmosphere of August 2011. Thermal-optical analysis, liquid and ion chromatography, IR spectroscopy, and electron microscopy were used to determine the organic content (OC) and elemental content (EC) of carbon, organic/inorganic and ionic compounds, and biomass burning markers (anhydrosaccharides and the potassium ion) and study the morphology and elemental composition of individual particles. It has been shown that the fires are characterized by an increased OC/EC ratio and high concentrations of ammonium, potassium, and sulfate ions in correlation with an increased content of levoglucosan as a marker of biomass burning. The organic compounds containing carbonyl groups point to the process of photochemical aging and the formation of secondary organic aerosols in the urban atmosphere when aerosols are emitted from forest fires. A cluster analysis of individual particles has indicated that when the smokiest atmosphere is characterized by prevailing soot/tar ball particles, which are smoke-emission micromarkers.

  13. Implementation of aerosol-cloud interactions in the regional atmosphere-aerosol model COSMO-MUSCAT(5.0) and evaluation using satellite data

    Science.gov (United States)

    Dipu, Sudhakar; Quaas, Johannes; Wolke, Ralf; Stoll, Jens; Mühlbauer, Andreas; Sourdeval, Odran; Salzmann, Marc; Heinold, Bernd; Tegen, Ina

    2017-06-01

    The regional atmospheric model Consortium for Small-scale Modeling (COSMO) coupled to the Multi-Scale Chemistry Aerosol Transport model (MUSCAT) is extended in this work to represent aerosol-cloud interactions. Previously, only one-way interactions (scavenging of aerosol and in-cloud chemistry) and aerosol-radiation interactions were included in this model. The new version allows for a microphysical aerosol effect on clouds. For this, we use the optional two-moment cloud microphysical scheme in COSMO and the online-computed aerosol information for cloud condensation nuclei concentrations (Cccn), replacing the constant Cccn profile. In the radiation scheme, we have implemented a droplet-size-dependent cloud optical depth, allowing now for aerosol-cloud-radiation interactions. To evaluate the models with satellite data, the Cloud Feedback Model Intercomparison Project Observation Simulator Package (COSP) has been implemented. A case study has been carried out to understand the effects of the modifications, where the modified modeling system is applied over the European domain with a horizontal resolution of 0.25° × 0.25°. To reduce the complexity in aerosol-cloud interactions, only warm-phase clouds are considered. We found that the online-coupled aerosol introduces significant changes for some cloud microphysical properties. The cloud effective radius shows an increase of 9.5 %, and the cloud droplet number concentration is reduced by 21.5 %.

  14. Geographical Distribution and Sources of Nutrients in Atmospheric Aerosol Over the Pacific Ocean

    Science.gov (United States)

    Uematsu, M.

    2016-12-01

    The Pacific Ocean, the world's largest (occupying about 30% of the Earth's total surface area) has several distinguishing biogeochemical features. In the western Pacific, dust particles originating from arid and semi-arid regions in Asia and Australia are transported to the north and south, respectively. Biomass burning emissions from Southeast Asia are exported to the tropical Pacific, and anthropogenic substances flowing out of Asia and Eurasia spread both regionally and globally. Over high primary productive areas such as the subarctic North Pacific, the equatorial Pacific and the Southern Ocean, biogenic gasses are released to the atmosphere and transported to other areas. These processes may affect cloud and rainfall patterns, air quality, and the radiative balance of downwind regions. The deposition of atmospheric aerosols containing iron and other essential nutrients is important for biogeochemical cycles in the oceans because this source of nutrients helps sustain primary production and affects food-web structure; these effects in turn influence the chemical properties of marine atmosphere. From an atmospheric chemistry standpoint, sea-salt aerosols produced by strong winds and marine biogenic gases emitted from highly productive waters affect the physicochemical characteristics of marine aerosols. As phytoplankton populations are patchy and atmospheric processes sporadic, the interactions between atmospheric chemical constituents and marine biota vary for different regions as well as seasonally and over longer timescales. To address these and other emerging issues, and more generally to better understand the important biogeochemical processes and interactions occurring over the open oceans, more long-term recurrent research cruises with standardized atmospheric shipboard measurements will be needed in the future.

  15. Atmospheric aerosol characterization with a ground-based SPEX spectropolarimetric instrument

    Science.gov (United States)

    van Harten, G.; de Boer, J.; Rietjens, J. H. H.; Di Noia, A.; Snik, F.; Volten, H.; Smit, J. M.; Hasekamp, O. P.; Henzing, J. S.; Keller, C. U.

    2014-12-01

    Characterization of atmospheric aerosols is important for understanding their impact on health and climate. A wealth of aerosol parameters can be retrieved from multi-angle, multi-wavelength radiance and polarization measurements of the clear sky. We developed a ground-based SPEX instrument (groundSPEX) for accurate spectropolarimetry, based on the passive, robust, athermal, and snapshot spectral polarization modulation technique, and is hence ideal for field deployment. It samples the scattering phase function in the principal plane in an automated fashion, using a motorized pan/tilt unit and automatic exposure time detection. Extensive radiometric and polarimetric calibrations were performed, yielding values for both random noise and systematic uncertainties. The absolute polarimetric accuracy at low degrees of polarization is established to be ~5 × 10-3. About 70 measurement sequences have been performed throughout four clear-sky days at Cabauw, the Netherlands. Several aerosol parameters were retrieved: aerosol optical thickness, effective radius, and complex refractive index for fine and coarse mode. The results are in good agreement with the colocated AERONET products, with a correlation coefficient of ρ = 0.932 for the total aerosol optical thickness at 550 nm.

  16. 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.

    Science.gov (United States)

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

    2015-10-06

    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.

  17. The System of the Calibration for Visibility Measurement Instrument Under the Atmospheric Aerosol Simulation Environment

    Directory of Open Access Journals (Sweden)

    Shu Zhifeng

    2016-01-01

    Full Text Available Visibility is one of the most important parameters for meteorological observation and numerical weather prediction (NWP.It is also an important factor in everyday life, mainly for surface and air traffic especially in the Aeronautical Meteorology. The visibility decides the taking off and landing of aircraft. If the airport visibility is lower than requirement for aircraft taking off stipulated by International Civil Aviation Administration, then the aircraft must be parked at the airport. So the accurate measurement of visibility is very important. Nowadays, many devices can be measured the visibility or meteorological optical range (MOR such as Scatterometers, Transmissometers and visibility lidar. But there is not effective way to verify the accuracy of these devices expect the artificial visual method. We have developed a visibility testing system that can be calibration and verification these devices. The system consists of laser transmitter, optical chopper, phase-locking amplifier, the moving optic receiving system, signal detection and data acquisition system, atmospheric aerosol simulation chamber. All of them were placed in the atmosphere aerosol simulation chamber with uniform aerosol concentration. The Continuous wave laser, wavelength 550nm, has been transmitted into the collimation system then the laser beam expanded into 40mm diameter for compressing the laser divergence angle before modulated by optical chopper. The expanding beam transmitting in the atmosphere aerosol cabin received by the optic receiving system moving in the 50m length precision guide with 100mm optical aperture. The data of laser signal has been acquired by phase-locking amplifier every 5 meter range. So the 10 data points can be detected in the 50 meters guide once. The slope of the fitting curve can be obtained by linear fitting these data using the least square method. The laser extinction coefficient was calculated from the slope using the Koschmieder

  18. Organic Aerosol Volatility Parameterizations and Their Impact on Atmospheric Composition and Climate

    Science.gov (United States)

    Tsigaridis, Konsta; Bauer, Susanne E.

    2015-01-01

    Despite their importance and ubiquity in the atmosphere, organic aerosols are still very poorly parameterized in global models. This can be explained by two reasons: first, a very large number of unconstrained parameters are involved in accurate parameterizations, and second, a detailed description of semi-volatile organics is computationally very expensive. Even organic aerosol properties that are known to play a major role in the atmosphere, namely volatility and aging, are poorly resolved in global models, if at all. Studies with different models and different parameterizations have not been conclusive on whether the additional complexity improves model simulations, but the added diversity of the different host models used adds an unnecessary degree of variability in the evaluation of results that obscures solid conclusions.

  19. Modeling Greenland's Climate Response to the Presence of Biomass Burning Aerosols in the Atmosphere and Snow

    Science.gov (United States)

    Ward, J. L.; Flanner, M.; Bergin, M. H.; Courville, Z.; Dibb, J. E.; Polashenski, C.; Soja, A. J.; Strellis, B. M.

    2015-12-01

    Biomass burning events are known to produce large emissions of aerosol particles, including light-absorbing black carbon (BC) and brown carbon. Once exported from fire-based source regions to the Arctic via atmospheric transport mechanisms, these particles can change the regional climate through solar absorption while suspended at various heights in the atmosphere or once deposited onto the terrain (through the reduction of surface albedo). Greenland is particularly vulnerable to positive aerosol forcing due to its perennial ice cover and high surface albedo. Surface measurements and remote sensing observations indicate that Greenland is occasionally impacted by smoke from North American and Eurasian wildfires, including during the summer of 2011 when aerosol optical depth (AOD) over central Greenland exceeded 0.20 and aerosol single scattering albedo (SSA) dropped below 0.90. Measurements of impurities in snow pits also indicate that wildfires exerted transient influence on surface albedo during the summers of 2012 and 2013, with average peak BC concentrations of 4 and 15 ng/g, respectively. Here, we apply idealized climate simulations to study how Greenland surface temperature and melt are affected by elevated levels of light-absorbing particles above and on the ice sheet. We apply the Community Earth System Model (CESM) in a configuration with prescribed sea surface temperatures and active atmosphere and land model components. In one set of experiments, we prescribe constant values of AOD and SSA in the troposphere over Greenland, informed by measurements from 2011. In a second set of experiments we prescribe constant mass mixing ratios of BC and dust in surface snow based on measurements of snow that fell during 2012-2014. These simulations will inform on the amount of excess snow melt that may occur on Greenland due to biomass burning, and on the relative impacts of atmospheric and snow-deposited smoke.

  20. Cosmic ray decreases affect atmospheric aerosols and clouds

    DEFF Research Database (Denmark)

    Svensmark, Henrik; Bondo, Torsten; Svensmark, J.

    2009-01-01

    Close passages of coronal mass ejections from the sun are signaled at the Earth's surface by Forbush decreases in cosmic ray counts. We find that low clouds contain less liquid water following Forbush decreases, and for the most influential events the liquid water in the oceanic atmosphere can...... diminish by as much as 7%. Cloud water content as gauged by the Special Sensor Microwave/Imager (SSM/I) reaches a minimum ≈7 days after the Forbush minimum in cosmic rays, and so does the fraction of low clouds seen by the Moderate Resolution Imaging Spectroradiometer (MODIS) and in the International......, and liquid-water clouds appears to exist on a global scale....

  1. Simulated nutrient dissolution of Asian aerosols in various atmospheric waters: Potential links to marine primary productivity

    Science.gov (United States)

    Wang, Lingyan; Bi, Yanfeng; Zhang, Guosen; Liu, Sumei; Zhang, Jing; Xu, Zhaomeng; Ren, Jingling; Zhang, Guiling

    2017-09-01

    To probe the bioavailability and environmental mobility of aerosol nutrient elements (N, P, Si) in atmospheric water (rainwater, cloud and fog droplets), ten total suspended particulate (TSP) samples were collected at Fulong Mountain, Qingdao from prevailing air mass trajectory sources during four seasons. Then, a high time-resolution leaching experiment with simulated non-acidic atmospheric water (non-AAW, Milli-Q water, pH 5.5) and subsequently acidic atmospheric water (AAW, hydrochloric acid solution, pH 2) was performed. We found that regardless of the season or source, a monotonous decreasing pattern was observed in the dissolution of N, P and Si compounds in aerosols reacted with non-AAW, and the accumulated dissolved curves of P and Si fit a first-order kinetic model. No additional NO3- + NO2- dissolved out, while a small amount of NH4+ in Asian dust (AD) samples was released in AAW. The similar dissolution behaviour of P and Si from non-AAW to AAW can be explained by the Transition State Theory. The sources of aerosols related to various minerals were the natural reasons that affected the amounts of bioavailable phosphorus and silicon in aerosols (i.e., solubility), which can be explained by the dissolution rate constant of P and Si in non-AAW with lower values in mineral aerosols. The acid/particle ratio and particle/liquid ratio also have a large effect on the solubility of P and Si, which was implied by Pearson correlation analysis. Acid processing of aerosols may have great significance for marine areas with limited P and Si and post-acidification release increases of 1.1-10-fold for phosphorus and 1.2-29-fold for silicon. The decreasing mole ratio of P and Si in AAW indicates the possibility of shifting from a Si-limit to a P-limit in aerosols in the ocean, which promotes the growth of diatoms prior to other algal species.

  2. Simple aerosol correction technique based on the spectral relationships of the aerosol multiple-scattering reflectances for atmospheric correction over the oceans.

    Science.gov (United States)

    Ahn, Jae-Hyun; Park, Young-Je; Kim, Wonkook; Lee, Boram

    2016-12-26

    An estimation of the aerosol multiple-scattering reflectance is an important part of the atmospheric correction procedure in satellite ocean color data processing. Most commonly, the utilization of two near-infrared (NIR) bands to estimate the aerosol optical properties has been adopted for the estimation of the effects of aerosols. Previously, the operational Geostationary Color Ocean Imager (GOCI) atmospheric correction scheme relies on a single-scattering reflectance ratio (SSE), which was developed for the processing of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data to determine the appropriate aerosol models and their aerosol optical thicknesses. The scheme computes reflectance contributions (weighting factor) of candidate aerosol models in a single scattering domain then spectrally extrapolates the single-scattering aerosol reflectance from NIR to visible (VIS) bands using the SSE. However, it directly applies the weight value to all wavelengths in a multiple-scattering domain although the multiple-scattering aerosol reflectance has a non-linear relationship with the single-scattering reflectance and inter-band relationship of multiple scattering aerosol reflectances is non-linear. To avoid these issues, we propose an alternative scheme for estimating the aerosol reflectance that uses the spectral relationships in the aerosol multiple-scattering reflectance between different wavelengths (called SRAMS). The process directly calculates the multiple-scattering reflectance contributions in NIR with no residual errors for selected aerosol models. Then it spectrally extrapolates the reflectance contribution from NIR to visible bands for each selected model using the SRAMS. To assess the performance of the algorithm regarding the errors in the water reflectance at the surface or remote-sensing reflectance retrieval, we compared the SRAMS atmospheric correction results with the SSE atmospheric correction using both simulations and in situ match-ups with the

  3. Reconstruction of Holocene and LGM atmospheric dust aerosol concentrations from paleoclimatic archives

    Science.gov (United States)

    Lambert, F.; Kug, J. S.; Park, R. J.; Mahowald, N.; Abe-Ouchi, A.; O'Ishi, R.; Winckler, G.; Takemura, T.

    2012-04-01

    Atmospheric mineral dust aerosols affect the global climate by scattering and absorbing solar and thermal radiation, as well as providing micronutrients to primary production regions. Present and past global atmospheric dust concentrations have so far been deduced from model simulations. We present a new estimate of atmospheric dust concentrations and dust aerosol radiative forcing based on measurements of dust deposition in paleoclimate archives (mainly the DIRTMAP 3 dataset). Using a kriging technique, the dust deposition data from terrestrial, marine, and ice core records was interpolated to a global grid for both average Holocene and Last Glacial Maximum climatic conditions. By combining the data with some parameters from dust models we reconstructed Holocene and LGM surface and atmospheric dust concentrations. This new dataset's dust concentrations and radiative forcing is compared to the results from dust model simulations. We show how this new dataset can be used by calculating dust radiative forcing in polar areas. Dust appears to play an important role in the polar amplification phenomenon during dusty times by cooling down the surface and heating the upper atmospheric layers.

  4. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India

    Energy Technology Data Exchange (ETDEWEB)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Kotalo, Rama Gopal, E-mail: krgverma@yahoo.com [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Rajuru Ramakrishna, Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Srinivasa Ramanujan Institute of Technology, B.K. Samudram Mandal, Anantapur 515 701, Andhra Pradesh (India); Surendranair, Suresh Babu [Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum 695 022, Kerala (India)

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500 nm are found to be 0.47 ± 0.09, 0.34 ± 0.08, 0.29 ± 0.06 and 0.30 ± 0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α{sub 380–1020}) value is observed maximum in March (1.25 ± 0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33 ± 0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00–08:00 (IST) and evening 19:00–21:00 (IST) hours and one minima noticed during afternoon (13:00–16:00). The highest monthly mean BC concentration is observed in the month of January (3.4 ± 1.2 μg m{sup −3}) and the lowest in July (1.1 ± 0.2 μg m{sup −3}). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be + 36.8 ± 1.7 W m{sup −2}, + 26.9 ± 0.2 W m{sup −2}, + 18.0 ± 0.6 W m{sup −2} and + 18.5 ± 3.1 W m{sup −2} during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80 W m{sup −2}) which contributes more increase in atmospheric heating by ~ 1 K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. - Highlights: • The mean values of AOD{sub 500} are found to be high during summer whereas low in monsoon. • The highest values of BC are observed in January and the lowest in the month of July. • The annual mean

  5. Variation of atmospheric aerosol components and sources during smog episodes in Debrecen, Hungary

    Energy Technology Data Exchange (ETDEWEB)

    Angyal, A.; Kertész, Zs.; Szoboszlai, Z.; Szikszai, Z. [lnstitute of Nuclear Research of the Hungarian Academy of Sciences (Atomki), Laboratory of lon Beam Applications, Debrecen (Hungary); Ferenczi, Z. [Hungarian Meteorological Service, Budapest (Hungary); Furu, E.; Tõrõk, Zs. [University of Debrecen, Debrecen (Hungary)

    2013-07-01

    Full text: Atmospheric particulate matter (APM) pollution is one of the leading environmental problems in densely populated urban environments. In most cities all around the world high aerosol pollution levels occurs regularly. Debrecen, an average middle-European city is no exception. Every year there are several days when the aerosol pollution level exceeds the alarm threshold value (100 μ-g/m{sup 3} for PM10 in 24- hours average). When the PM10 pollution level remains over this limit value for days, it is called 'smog' by the authorities. In this work we studied the variation of the elemental components and sources of PM10, PM2.5 and PM coarse and their dependence on meteorological conditions in Debrecen during two smog episodes occurred in November 2011. Aerosol samples were collected with 2-hours time resolution with a PIXE International sequential streaker in an urban background site in the downtown of Debrecen. In order to get information about the size distribution of the aerosol elemental components 9-stage cascade impactors were also employed during the sampling campaigns. The elemental composition (Z ≥ 13) were determined by Particle Induced X-Ray Emission (PIXE) at the IBA Laboratory of Atomki. Concentrations of elemental carbon were measured with a smoke stain reflectometer. On this data base source apportionment was carried out by using the positive matrix factorisation (PMF) method. Four factors were identified for both size fractions, including soil dust, traffic, domestic heating, and oil combustion. The time pattern of the aerosol elemental components and PM sources exhibited strong dependence on the mixing layer thickness. We showed that domestic heating had a major contribution to the aerosol pollution. (This work was carried out in the frame of the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and TÁMOP-4.2.2/B-10/1-2010-0024 project). (author)

  6. The effects of heterogeneous reactions on atmospheric chemistry and aerosol properties

    Science.gov (United States)

    Wei, Chao; Carmichael, Gregory; Su, Hang; Cheng, Yafang

    2017-04-01

    A new aerosol module is developed for the STEM model (the Sulfur Transport and dEposition Model) to better understand the chemical aging of dust during long range transport and assess the impact of heterogeneous reactions on tropospheric chemistry. The new aerosol module is verified and first applied in a box model, and then coupled into the 3-Dimentional STEM model. In the new aerosol model, a nonequilibrium (dynamic or kinetic) approach to treat gas-to-particle conversion is employed to replace the equilibrium method in STEM model. Meanwhile, a new numerical method solving the aerosol dynamics equation is introduced into the dynamic aerosol model for its improved computational efficiency and high accuracy. Compared with the equilibrium method, the new dynamic approach is found to provide better results on predicating the different hygroscopicity and chemical aging patterns as a function of size. The current modeling study also takes advantage of new findings from laboratory experiments about heterogeneous reactions on mineral oxides and dust particles, in order to consider the complexity of surface chemistry (such as surface saturation, coating and relative humidity). Modeling results show that the impacts of mineralogy and relative humidity on heterogeneous reactions are significant and should be considered in atmospheric chemistry modeling with first priority. The new dynamic approach for gas-to-particle conversion and RH-dependent heterogeneous uptake of HNO3 improve the model performance in term of aerosol predictions under different conditions. It is shown that these improvements change the modeled nitrate and sulfate concentrations, but also modify their size distributions significantly.

  7. Evaluation of the atmospheric significance of multiphase reactions in atmospheric secondary organic aerosol formation

    Directory of Open Access Journals (Sweden)

    Gelencsér

    2005-01-01

    Full Text Available In a simple conceptual cloud-aerosol model the mass of secondary organic aerosol (SOA that may be formed in multiphase reaction in an idealized scenario involving two cloud cycles separated with a cloud-free period is evaluated. The conditions are set to those typical of continental clouds, and each parameter used in the model calculations is selected as a mean of available observational data of individual species for which the multiphase SOA formation route has been established. In the idealized setting gas and aqueous-phase reactions are both considered, but only the latter is expected to yield products of sufficiently low volatility to be retained by aerosol particles after the cloud dissipates. The key variable of the model is the Henry-constant which primarily determines how important multiphase reactions are relative to gas-phase photooxidation processes. The precursor considered in the model is assumed to already have some affinity to water, i.e. it is a compound having oxygen-containing functional group(s. As a principal model output an aerosol yield parameter is calculated for the multiphase SOA formation route as a function of the Henry-constant, and has been found to be significant already above H~103 M atm-1. Among the potential precursors that may be eligible for this mechanism based on their Henry constants, there are a suite of oxygenated compounds such as primary oxidation products of biogenic and anthropogenic hydrocarbons, including, for example, pinonaldehyde. Finally, the analogy of multiphase SOA formation to in-cloud sulfate production is exploited.

  8. A sub-decadal trend in diacids in atmospheric aerosols in eastern Asia

    Directory of Open Access Journals (Sweden)

    S. Kundu

    2016-01-01

    Full Text Available Change in secondary organic aerosols (SOAs has been predicted to be highly uncertain in the future atmosphere in Asia. To better quantify the SOA change, we examine the sub-decadal (2001–2008 trend in major surrogate compounds (C2–C10 diacids of SOA in atmospheric aerosols from Gosan site on Cheju Island, South Korea. The Gosan site is influenced by pollution outflows from eastern Asia. The molecular distributions of diacids were characterized by the predominance of oxalic (C2 acid followed by malonic (C3 and succinic (C4 acids in each year. The seasonal variations in diacids in each year were characterized by the highest concentrations of saturated diacids in spring and unsaturated diacids in winter. The consistent molecular distributions and seasonal variations along with significantly similar air mass transport patterns are indicative of similar pollution sources for diacids in eastern Asia on a sub-decadal scale. However, the intensity of the pollution sources has increased as evidenced by the increases in major diacids at the rate of 3.9–47.4 % per year, particularly in April. The temporal variations in atmospheric tracer compounds (carbon monoxide, levoglucosan, 2-methyltetrols, pinic acid, glyoxylic acid, glyoxal and methylglyoxal suggest that the increases in diacids are due to enhanced precursor emissions associated with more anthropogenic than biogenic activities followed by the compounds' chemical processing in the atmosphere. The trends in diacids contrast with the reported decreases in sulfate, nitrate and ammonium in recent years in eastern Asia. This study demonstrates that recent pollution control strategies in eastern Asia were not able to decrease organic acidic species in the atmosphere. The increases in water-soluble organic acid fraction could modify the aerosol organic composition and its sensitivity to climate relevant physical properties.

  9. Atmospheric Aerosols: Cloud Condensation Nucleus Activity of Selected Organic Molecules

    Science.gov (United States)

    Rosenorn, T.; Henning, S.; Hartz, K. H.; Kiss, G.; Pandis, S.; Bilde, M.

    2005-12-01

    Gas/particle partitioning of vapors in the atmosphere plays a major role in both climate through micro meteorology and in the physical and chemical processes of a single particle. This work has focused on the cloud droplet activation of a number of pure and mixed compounds. The means used to investigate these processes have been the University of Copenhagen cloud condensation nucleus counter setup and the Carnegie Mellon University CCNC setup. The importance of correct water activity modeling has been addressed and it has been pointed out that the molecular mass is an important parameter to consider when choosing model compounds for cloud activation models. It was shown that both traditional Kohler theory and Kohler theory modified to account for limited solubility reproduce measurements of soluble compounds well. For less soluble compounds it is necessary to use Kohler theory modified to account for limited solubility. It was also shown that this works for mixtures of compounds containing both inorganic salts and dicarboxylic acids. It has also been shown that particle phase and humidity history is important for activation behavior of particles consisting of two slightly soluble organic substances (succinic and adipic acid) and a soluble salt (NaCl). Model parameters for terpene oxidation product cloud activation have been derived. These are based on two sets of average parameters covering monoterpene oxidation products and sesquiterpene oxidation products. All parameters except the solubility were estimated and an effective solubility was calculated as the fitting parameter. The average solubility of the model compound found for mono terpene oxidation products is similar to those of sodium chloride and ammonium sulfate; however the higher molecular weight leads to a slightly higher activation diameter at fixed supersaturation. On a molar basis the monoterpene oxidation products show a 1.5 times higher effective solubility than the sesquiterpene oxidation products.

  10. The Influence of High Aerosol Concentration on Atmospheric Boundary Layer Temperature Stratification

    Energy Technology Data Exchange (ETDEWEB)

    Khaykin, M.N.; Kadygrove, E.N.; Golitsyn, G.S.

    2005-03-18

    Investigations of the changing in the atmospheric boundary layer (ABL) radiation balance as cased by natural and anthropogenic reasons is an important topic of the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program. The influence of aerosol on temperature stratification of ABL while its concentration was extremely high within a long period of time was studied experimentally. The case was observed in Moscow region (Russia) with the transport of combustion products from peat-bog and forest fires in July-September, 2002. At this time the visibility was some times at about 100-300 m. Aerosol concentration measured by Moscow University Observatory and A.M. Obukhov Institute of Atmospheric Physics field station in Zvenigorod (55.7 N; 36.6 E) for several days was in 50-100 times more than background one (Gorchakov at al 2003). The high aerosol concentration can change the radiation balance at ABL, and so to change thermal stratification in ABL above the mega lopolis. For the analysis the data were used of synchronous measurements by MTP-5 (Microwave Temperature Profiler operating at wavelength 5 mm) in two locations, namely: downtown Moscow and country-side which is 50 km apart to the West (Zvenigorod station). (Kadygrov and Pick 1998; Westwater at al 1999; Kadygrov at al 2002). Zvenigorod station is located in strongly continental climate zone which is in between of the climates of ARM sites (NSANorth Slope of Alaska and SGP-Southern Great Plains). The town of Zvenigorod has little industry, small traffic volume and topography conductive to a good air ventilation of the town. For these reasons Zvenigorod can be considered as an undisturbed rural site. For the analysis some days were chosen with close meteorological parameters (average temperature, humidity, wind, pressure and cloud form) but strongly differing in aerosol concentration level.

  11. Radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer and its feedback on the haze formation

    Science.gov (United States)

    Wei, Chao; Su, Hang; Cheng, Yafang

    2016-04-01

    Planetary boundary layer (PBL) plays a key role in air pollution dispersion and influences day-to-day air quality. Some studies suggest that high aerosol loadings during severe haze events may modify PBL dynamics by radiative effects and hence enhance the development of haze. This study mainly investigates the radiative effects of tropospheric aerosols on the evolution of the atmospheric boundary layer by conducting simulations with Weather Research and Forecasting single-column model (WRF-SCM). We find that high aerosol loading in PBL depressed boundary layer height (PBLH). But the magnitude of the changes of PBLH after adding aerosol loadings in our simulations are small and can't explain extreme high aerosol concentrations observed. We also investigate the impacts of the initial temperature and moisture profiles on the evolution of PBL. Our studies show that the impact of the vertical profile of moisture is comparable with aerosol effects.

  12. Atmospheric configurations of aerosols loading and retention over Bolgatanga-Ghana

    Science.gov (United States)

    Emetere, M. E.; Sanni, S. E.; Tunji-Olayeni, P.

    2017-05-01

    Bolgatanga is located on latitude of 10.78 °N and longitude 0.85 °W. This research is aimed to estimate the aerosols loading and retention over Bolgatanga-Ghana through a conceptual model that is made up of analytical, statistical and Matlab curve-fitting tool. The model’s accuracy was established over the aerosol optical depth for a thirteen-year satellite data set from the Multi-angle imaging specto-reflectometer (MISR). The maximum aerosol retention was 31.73%. Its atmospheric constants, tunning constants and the phase difference over Bolgatanga was found to 0.67, 0.24 and ±π/4 respectively. The phase difference expresses the different kinds of network topologies and beam forming methods for measuring devices that may be used in Bolgatanga. Therefore a good estimation of the aerosols loading and retention over Bolgatanga, we may be in the best position to controlling its effect on health, farming, rainfall pattern, cloud formation and regional climate.

  13. Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST

    Directory of Open Access Journals (Sweden)

    K. Sellegri

    2005-01-01

    Full Text Available Biogenic VOCs are important in the growth and possibly also in the early stages of formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic trace gases at Hyytiälä, Finland during March 2002. The measurements were part of the project QUEST (Quantification of Aerosol Nucleation in the European Boundary Layer and took place during a two-week period when nucleation events occurred with various intensities nearly every day. Using a ground-based Chemical Ionization Mass Spectrometer (CIMS instrument, the following trace gases were detected: acetone, TMA, DMA, mass 68amu (candidate=isoprene, monoterpenes, methyl vinyl ketone (MVK and methacrolein (MaCR and monoterpene oxidation products (MTOP. For all of them except for the amines, we present daily variations during different classes of nucleation events, and non-event days. BVOC oxidation products (MVK, MaCR and MTOP show a higher ratio to the CS on event days compared to non-event days, indicating that their abundance relative to the surface of aerosol available is higher on nucleation days. Moreover, BVOC oxidation products are found to show significant correlations with the condensational sink (CS on nucleation event days, which indicates that they are representative of less volatile organic compounds that contribute to the growth of the nucleated particles and generally secondary organic aerosol formation. Behaviors of BVOC on event and non event days are compared to the behavior of CO.

  14. Biomonitoring of atmospheric pollution: a novel approach for the evaluation of natural and anthropogenic contribution to atmospheric aerosol particles.

    Science.gov (United States)

    Caggiano, Rosa; Calamita, Giuseppe; Sabia, Serena; Trippetta, Serena

    2017-03-01

    The investigation of the potential natural and anthropogenic contribution to atmospheric aerosol particles by using lichen-bag technique was performed in the Agri Valley (Basilicata region, southern Italy). This is an area of international concern since it houses one of the largest European on-shore reservoirs and the biggest oil/gas pre-treatment plant (i.e., Centro Olio Val d'Agri (COVA)) within an anthropized context. In particular, the concentrations of 17 trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Ti, and Zn) were measured in lichen bags exposed in 59 selected monitoring points over periods of 6 months (from October 2011 to April 2012) and 12 months (from October 2011 to October 2012). The general origin of the main air masses affecting the sampling site during the study period was assessed by the back trajectories clustering calculated using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results allowed the identification and characterization of the crustal material, smoke, sea salt, sulfate, and anthropogenic trace element contributions to the atmospheric aerosol particles in the study area. Finally, the application of the trend surface analysis (TSA) allowed the study of the spatial distribution of the considered contributions highlighting the existence of a continuous broad variation of these contributions in the area of interest.

  15. Interactions of liquid lithium with various atmospheres, concretes, and insulating materials; and filtration of lithium aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Jeppson, D W

    1979-06-01

    This report describes the facilities and experiments and presents test results of a program being conducted at the hanford Engineering Development Laboratory (HEDL) in support of the fusion reactor development effort. This experimental program is designed to characterize the interaction of liquid lithium with various atmospheres, concretes, and insulating materials. Lithium-atmosphere reaction tests were conducted in normal humidity air, pure nitrogen, and carbon dioxide. These tests are described and their results, such as maximum temperatures, aerosol generated, and reaction rates measured, are reported. Initial lithium temperatures for these tests ranged between 224/sup 0/C and 843/sup 0/C. A lithium-concrete reaction test, using 10 kg of lithium at 327/sup 0/C, and lithium-insulating materials reaction tests, using a few grams of lithium at 350/sup 0/C and 600/sup 0/C, are also described and results are presented. In addition, a lithium-aerosol filter loading test was conducted to determine the mass loading capacity of a commercial high efficiency particulate air (HEPA) filter. The aerosol was characterized, and the loading-capacity-versus-pressure-buildup across the filter is reported.

  16. Measurements of profiles of aerosol/cloud in the lower atmosphere using a lidar system

    Science.gov (United States)

    Gasmi, Khaled

    2016-10-01

    Preliminary measurements of profiles of aerosol/cloud in the lower atmosphere using a homemade stationary groundbased lidar system will be presented. In addition, information on basic characteristics and performance of the lidar system will be provided. Aerosol/Cloud lidar system in monostatic coaxial configuration uses the fundamental (1064 nm) and the second harmonic (532 nm) of a pulsed solid state Nd:YAG laser to provide information on the relative concentration and spatial distribution of aerosol particles and cloud water droplets. Beam expander is used to reduce the laser beam divergence before to be transmitted into the atmosphere. In this study, high-resolution vertical profiles from the near ground up to 15 km altitude are obtained. A Newtonian telescope of diameter 400 mm with an adjustable field of view (FOV) is used to collect the elastic backscattered signal. A photomultiplier tube (PMT) is used for the 532 nm wavelength detection channel, while an avalanche photodiode (APD) is used for the 1064 nm wavelength detection channel. The optoelectronic detection channels use two similar very high frequency preamplification circuit. Data are acquired with a nominal spatial resolution of 7.5 m using a 12-bit 20 MHz analog-to-digital converter (ADC) for each channel. Many functions, such as, range determination, background subtraction, digitization, and averaging are performed by the receiver subsystem. In addition, spatial resolution and linear dynamic range were optimized during signal processing.

  17. Chemical composition of aerosol in the atmospheric surface layer of the East Antarctica coastal zone

    Directory of Open Access Journals (Sweden)

    L. P. Golobokova

    2016-01-01

    Full Text Available Chemical composition of aerosol in the ground layer of the coastal zone in East Antarctica is analyzed in the article. The aerosol samples were taken in 2006–2015 during seasonal works of the Russian Antarctic Expeditions (RAE, namely, these were 52nd–53rd, 55th, and 58th–60th expeditions. Samples were taken in the 200‑km band of the sea-shore zone along routes of the research vessels (REV «Akademik Fedorov» and «Akademik Treshnikov» as well as on territories of the Russian stations Molodezhnaya and Mirny. Although the results obtained did show the wide range of the aerosol concentrations and a certain variability of their chemical composition, some common features of the variability were revealed. Thus, during the period from 2006 to 2014 a decrease of average values of the sums were noted. Spatially, a tendency of decreasing of the ion concentrations was found in the direction from the station Novolazarevskaya to the Molodezhnaya one, but the concentrations increased from the Molodezhnaya to the station Mirny. The sum of ions of the aerosol in the above mentioned coastal zone was, on the average, equal to 2.44 μg/m3, and it was larger than that on the territory of the Antarctic stations Molodezhnaya (0,29 μg/m3 and Mirny (0,50 ág / m3. The main part to the sum of the aerosol ions on the Antarctic stations was contributed by Na+, Ca2+, Cl−, SO4 2−. The main ions in aerosol composition in the coastal zone are ions Na+ and Cl−. The dominant contribution of the sea salt and SO4 2− can be traced in not only the composition of atmospheric aerosols, but also in the chemical composition of the fresh snow in the coastal areas of East Antarctica: at the Indian station Maitri, on the Larsemann Hills, and in a boring located in 55.3 km from the station Progress (K = 1.4÷6.1. It was noted that values of the coefficient of enrichment K of these ions decreases as someone moves from a shore to inland. Estimation of

  18. he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study

    Energy Technology Data Exchange (ETDEWEB)

    Keene, William C. [University of Virginia; Long, Michael S. [University of Virginia

    2013-05-20

    This project examined the potential large-scale influence of marine aerosol cycling on atmospheric chemistry, physics and radiative transfer. Measurements indicate that the size-dependent generation of marine aerosols by wind waves at the ocean surface and the subsequent production and cycling of halogen-radicals are important but poorly constrained processes that influence climate regionally and globally. A reliable capacity to examine the role of marine aerosol in the global-scale atmospheric system requires that the important size-resolved chemical processes be treated explicitly. But the treatment of multiphase chemistry across the breadth of chemical scenarios encountered throughout the atmosphere is sensitive to the initial conditions and the precision of the solution method. This study examined this sensitivity, constrained it using high-resolution laboratory and field measurements, and deployed it in a coupled chemical-microphysical 3-D atmosphere model. First, laboratory measurements of fresh, unreacted marine aerosol were used to formulate a sea-state based marine aerosol source parameterization that captured the initial organic, inorganic, and physical conditions of the aerosol population. Second, a multiphase chemical mechanism, solved using the Max Planck Institute for Chemistry's MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) system, was benchmarked across a broad set of observed chemical and physical conditions in the marine atmosphere. Using these results, the mechanism was systematically reduced to maximize computational speed. Finally, the mechanism was coupled to the 3-mode modal aerosol version of the NCAR Community Atmosphere Model (CAM v3.6.33). Decadal-scale simulations with CAM v.3.6.33, were run both with and without reactive-halogen chemistry and with and without explicit treatment of particulate organic carbon in the marine aerosol source function. Simulated results were interpreted (1) to evaluate influences

  19. Aqueous organic chemistry in the atmosphere: sources and chemical processing of organic aerosols.

    Science.gov (United States)

    McNeill, V Faye

    2015-02-03

    Over the past decade, it has become clear that aqueous chemical processes occurring in cloud droplets and wet atmospheric particles are an important source of organic atmospheric particulate matter. Reactions of water-soluble volatile (or semivolatile) organic gases (VOCs or SVOCs) in these aqueous media lead to the formation of highly oxidized organic particulate matter (secondary organic aerosol; SOA) and key tracer species, such as organosulfates. These processes are often driven by a combination of anthropogenic and biogenic emissions, and therefore their accurate representation in models is important for effective air quality management. Despite considerable progress, mechanistic understanding of some key aqueous processes is still lacking, and these pathways are incompletely represented in 3D atmospheric chemistry and air quality models. In this article, the concepts, historical context, and current state of the science of aqueous pathways of SOA formation are discussed.

  20. Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry

    Science.gov (United States)

    Farmer, D. K.; Matsunaga, A.; Docherty, K. S.; Surratt, J. D.; Seinfeld, J. H.; Ziemann, P. J.; Jimenez, J. L.

    2010-01-01

    Organonitrates (ON) are important products of gas-phase oxidation of volatile organic compounds in the troposphere; some models predict, and laboratory studies show, the formation of large, multifunctional ON with vapor pressures low enough to partition to the particle phase. Organosulfates (OS) have also been recently detected in secondary organic aerosol. Despite their potential importance, ON and OS remain a nearly unexplored aspect of atmospheric chemistry because few studies have quantified particulate ON or OS in ambient air. We report the response of a high-resolution time-of-flight aerosol mass spectrometer (AMS) to aerosol ON and OS standards and mixtures. We quantify the potentially substantial underestimation of organic aerosol O/C, commonly used as a metric for aging, and N/C. Most of the ON-nitrogen appears as ions in the AMS, which are typically dominated by inorganic nitrate. Minor organonitrogen ions are observed although their identity and intensity vary between standards. We evaluate the potential for using fragment ratios, organonitrogen ions, ions, the ammonium balance of the nominally inorganic ions, and comparison to ion-chromatography instruments to constrain the concentrations of ON for ambient datasets, and apply these techniques to a field study in Riverside, CA. OS manifests as separate organic and sulfate components in the AMS with minimal organosulfur fragments and little difference in fragmentation from inorganic sulfate. The low thermal stability of ON and OS likely causes similar detection difficulties for other aerosol mass spectrometers using vaporization and/or ionization techniques with similar or larger energy, which has likely led to an underappreciation of these species. PMID:20194777

  1. Do organic surface films on sea salt aerosols influence atmospheric chemistry? ─ a model study

    Directory of Open Access Journals (Sweden)

    R. von Glasow

    2007-11-01

    Full Text Available Organic material from the ocean's surface can be incorporated into sea salt aerosol particles often producing a surface film on the aerosol. Such an organic coating can reduce the mass transfer between the gas phase and the aerosol phase influencing sea salt chemistry in the marine atmosphere. To investigate these effects and their importance for the marine boundary layer (MBL we used the one-dimensional numerical model MISTRA. We considered the uncertainties regarding the magnitude of uptake reduction, the concentrations of organic compounds in sea salt aerosols and the oxidation rate of the organics to analyse the possible influence of organic surfactants on gas and liquid phase chemistry with a special focus on halogen chemistry. By assuming destruction rates for the organic coating based on laboratory measurements we get a rapid destruction of the organic monolayer within the first meters of the MBL. Larger organic initial concentrations lead to a longer lifetime of the coating but lead also to an unrealistically strong decrease of O3 concentrations as the organic film is destroyed by reaction with O3. The lifetime of the film is increased by assuming smaller reactive uptake coefficients for O3 or by assuming that a part of the organic surfactants react with OH. With regard to tropospheric chemistry we found that gas phase concentrations for chlorine and bromine species decreased due to the decreased mass transfer between gas phase and aerosol phase. Aqueous phase chlorine concentrations also decreased but aqueous phase bromine concentrations increased. Differences for gas phase concentrations are in general smaller than for liquid phase concentrations. The effect on gas phase NO2 or NO is very small (reduction less than 5% whereas liquid phase NO2 concentrations increased in some cases by nearly 100%. We list suggestions for further laboratory studies which are needed for improved model studies.

  2. Simulation of the Aerosol-Atmosphere Interaction in the Dead Sea Area with COSMO-ART

    Science.gov (United States)

    Vogel, Bernhard; Bangert, Max; Kottmeier, Christoph; Rieger, Daniel; Schad, Tobias; Vogel, Heike

    2014-05-01

    The Dead Sea is a unique environment located in the Dead Sea Rift Valley. The fault system of the Dead Sea Rift Valley marks the political borders between Israel, Jordan, and Palestine. The Dead Sea region and the ambient Eastern Mediterranean coastal zone provide a natural laboratory for studying atmospheric processes ranging from the smallest scale of cloud processes to regional weather and climate. The virtual institute DESERVE is designed as a cross-disciplinary and cooperative international project of the Helmholtz Centers KIT, GFZ, and UFZ with well-established partners in Israel, Jordan and Palestine. One main focus of one of the work packages is the role of aerosols in modifying clouds and precipitation and in developing the Dead Sea haze layer as one of the most intriguing questions. The haze influences visibility, solar radiation, and evaporation and may even affect economy and health. We applied the online coupled model system COSMO-ART, which is able to treat the feedback processes between aerosol, radiation, and cloud formation, for a case study above the Dead Sea and adjacent regions. Natural aerosol like mineral dust and sea salt as well as anthropogenic primary and secondary aerosol is taken into account. Some of the observed features like the vertical double structure of the haze layer are already covered by the simulation. We found that absorbing aerosol like mineral dust causes a temperature increase in parts of the model domain. In other areas a decrease in temperature due to cirrus clouds modified by elevated dust layers is simulated.

  3. Forecasting of aerosol extinction of the sea and coastal atmosphere surface layer

    Science.gov (United States)

    Kaloshin, G. A.

    2010-04-01

    The focus of our study is the extinction and optical effects due to aerosol in a specific coastal region. The aerosol microphysical model of the marine and coastal atmosphere surface layer is considered. The model is made on the basis of the long-term experimental data received at researches of aerosol sizes distribution function (dN/dr) in the band particles sizes in 0.01 - 100 μk. The model is developed by present time for the band of heights is 0 - 25 m. Bands of wind speed is 3 - 18 km/s, sizes fetch is up to 120 km, RH = 40 - 98 %. Key feature of model is parameterization of amplitude and width of the modes as functions of fetch and wind speed. In the paper the dN/dr behavior depending at change meteorological parameters, heights above sea level, fetch (X), wind speed (U) and RH is show. On the basis of the developed model with usage of Mie theory for spheres the description of last version of developed code MaexPro (Marine Aerosol Extinction Profiles) for spectral profiles of aerosol extinction coefficients α(λ) calculations in the wavelength band, equal λ = 0.2 - 12 μm is presented. The received results are compared models NAN and ANAM. Also α(λ) profiles for various wind modes (combinations X and U) calculated by MaexPro code are given. The calculated spectrums of α(λ) profiles are compared with experimental data of α(λ) received by a transmission method in various geographical areas.

  4. Is Distant Pollution Contaminating Local Air? Analyzing the Origins of Atmospheric Aerosols

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    David Geng

    2012-01-01

    Full Text Available Understanding the origin of aerosols in the atmosphere is important because of visual pollution, climate impacts, and deleterious health effects due to the inhalation of fine particles. This research analyzed aerosols characterized by their chloride, sulfate, and nitrate content as a function of size over a 3-month period. Due to wind patterns over coal-burning power plants, a higher concentration of local sulfate pollution was expected. Aerosols were harvested on the Purdue University campus using a high-volume air sampler with glass fiber filters and a five-stage impactor that separates the aerosols into five sizes. The filters were extracted in water to dissolve anions and the solution was analyzed using high-pressure liquid ion chromatography. Only trace amounts of chloride with no distinct patterns in size were detected. In total, nitrate content ranged from 0.12 to 2.10 μg/m3 and sulfate content ranged from 0.44 to 6.45 μg/m3 over a 3-month period. As for fine particles, a higher concentration of sulfate was observed. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT model determines air mass origin, and in this study, higher total sulfate content was observed when the air mass moved out of the southwest, and higher total nitrate content was observed when the air mass originated from the southeast. The author concluded that small particles resulted in sulfate from sulfur dioxide, typically from gas to particle conversion. High sulfur dioxide levels are directly correlated with coal-burning power plant density. Small particulate sulfate found in West Lafayette, Indiana, was determined to originate primarily from power plants in southwest Indiana. Though the results do show a significant amount of potentially harmful aerosols in West Lafayette, there is still further research to be done concerning isotopic composition of those particles in attempts to better explain the chemical pathways.

  5. Natural versus anthropogenic inhalable aerosol chemistry of transboundary East Asian atmospheric outflows into western Japan.

    Science.gov (United States)

    Moreno, Teresa; Kojima, Tomoko; Querol, Xavier; Alastuey, Andrés; Amato, Fulvio; Gibbons, Wes

    2012-05-01

    The eastward transport of aerosols exported from mainland Asia strongly influences air quality in the Japanese archipelago. The bulk of the inhalable particulate matter (PM(10)) in these intrusions comprises either natural, desert-derived minerals (mostly supermicron silicates) or anthropogenic pollutants (mostly submicron sulphates), in various states of mixing. We analyse PM(10) collected in Kumamoto, SW Japan, during three contrasting types of aerosol intrusions, the first being dominated by desert PM which became increasingly mixed with anthropogenic components as time progressed, the second being a relatively minor event mixing fine, distal desert PM with anthropogenic materials, and the third being dominated by anthropogenic pollutants. Whereas the chemistry of the natural mineral component is characterised by "crustal" elements (Si, Al, Fe, Mg, K, Li, P, Sc, V, Rb, Sr, Zr, Th, lanthanoids), the anthropogenic component is rich in secondary inorganic compounds and more toxic metallic elements (NH(4)(+), SO(4)(2-), As, Pb, Cd, Cu, Zn, Sn, Bi, Sb, and Ge). Some desert-dust (Kosa) intrusions are more calcareous than others, implicating geologically different source areas, and contain enhanced levels of NO(3)(-), probably as supermicron Ca(NO(3))(2) particles produced by chemical reaction between NOx pollutants (mostly from industry and traffic) and carbonate during atmospheric transport. The overall trace element chemistry of aerosol intrusions into Kumamoto shows low V/Rb, low NO(3)(-)/SO(4)(2-), enhanced As levels, and unfractionated La/Ce values, which are all consistent with anthropogenic sources including coal emissions rather than those derived from the refining and combustion of oil fractionates. Geographically dispersed, residual sulphatic plumes of this nature mix with local traffic (revealed by OC and EC concentrations) and industrial emissions and dissipate only slowly, due to the dominance of submicron accumulation mode PM which is atmospherically

  6. Ice nucleation properties of atmospheric aerosol particles collected during a field campaign in Cyprus

    Science.gov (United States)

    Yordanova, Petya; Maier, Stefanie; Lang-Yona, Naama; Tamm, Alexandra; Meusel, Hannah; Pöschl, Ulrich; Weber, Bettina; Fröhlich-Nowoisky, Janine

    2017-04-01

    Atmospheric aerosol particles, including desert and soil dust as well as marine aerosols, are well known to act as ice nuclei (IN) and thus have been investigated in numerous ice nucleation studies. Based on their cloud condensation nuclei potential and their impacts on radiative properties of clouds (via scattering and absorption of solar radiation), aerosol particles may significantly affect the cloud and precipitation development. Atmospheric aerosols of the Eastern Mediterranean have been described to be dominated by desert dust, but only little is known on their composition and ice nucleating properties. In this study we investigated the ice nucleating ability of total suspended particles (TSP), collected at the remote site Agia Marina Xyliatou on Cyprus during a field campaign in April 2016. Airborne TSP samples containing air masses of various types such as African (Saharan) and Arabian dust and European and Middle Eastern pollution were collected on glass fiber filters at 24 h intervals. Sampling was performed ˜5 m above ground level and ˜521 m above sea level. During the sampling period, two major dust storms (PM 10max 118 μg/m3 and 66 μg/m3) and a rain event (rainfall amount: 3.4 mm) were documented. Chemical and physical characterizations of the particles were analyzed experimentally through filtration, thermal, chemical and enzyme treatments. Immersion freezing experiments were performed at relatively high subzero temperatures (-1 to -15˚ C) using the mono ice nucleation array. Preliminary results indicate that highest IN particle numbers (INPs) occurred during the second dust storm event with lower particle concentrations. Treatments at 60˚ C lead to a gradual IN deactivation, indicating the presence of biological INPs, which were observed to be larger than 300 kDa. Additional results originating from this study will be shown. Acknowledgement: This work was funded by the DFG Ice Nuclei Research Unit (INUIT).

  7. Continuous standalone controllable aerosol/cloud droplet dryer for atmospheric sampling

    Science.gov (United States)

    Sjogren, S.; Frank, G. P.; Berghof, M. I. A.; Martinsson, B. G.

    2012-08-01

    We describe a general-purpose dryer designed for continuous sampling of atmospheric aerosol, where a specified relative humidity (RH) of the sample flow (lower than the atmospheric humidity) is required. It is often prescribed to measure the properties of dried aerosol, for instance for monitoring networks. The specific purpose of our dryer is to dry highly charged cloud droplets (maximum diameter approximately 25 μm) with minimum losses from the droplet size distribution entering the dryer as well as on the residual dry particle size distribution exiting the dryer. This is achieved by using a straight vertical downwards path from the aerosol inlet mounted above the dryer, and removing humidity to a dry closed loop airflow on the other side of a semi-permeable GORE-TEX membrane (total area 0.134 m2). The water vapour transfer coefficient, k, was measured to 4.6 × 10-7 kg m-2 s-1% RH-1 in the laboratory and is used for design purposes. A net water vapour transfer rate of up to 1.2 × 10-6 kg s-1 was achieved in the field. This corresponds to drying a 5.7 L min-1 (0.35 m3 h-1) aerosol sample flow from 100% RH to 27% RH at 293 K (with a drying air total flow of 8.7 L min-1). The system was used outdoors from 9 May until 20 October 2010, on the mountain Brocken (51.80° N, 10.67° E, 1142 m a.s.l.) in the Harz region in central Germany. Sample air relative humidity of less than 30% was obtained 72% of the time period. The total availability of the measurement system was > 94% during these five months.

  8. Continuous stand-alone controllable aerosol/cloud droplet dryer for atmospheric sampling

    Science.gov (United States)

    Sjogren, S.; Frank, G. P.; Berghof, M. I. A.; Martinsson, B. G.

    2013-02-01

    We describe a general-purpose dryer designed for continuous sampling of atmospheric aerosol, where a specified relative humidity (RH) of the sample flow (lower than the atmospheric humidity) is required. It is often prescribed to measure the properties of dried aerosol, for instance for monitoring networks. The specific purpose of our dryer is to dry cloud droplets (maximum diameter approximately 25 μm, highly charged, up to 5 × 102 charges). One criterion is to minimise losses from the droplet size distribution entering the dryer as well as on the residual dry particle size distribution exiting the dryer. This is achieved by using a straight vertical downwards path from the aerosol inlet mounted above the dryer, and removing humidity to a dry, closed loop airflow on the other side of a semi-permeable GORE-TEX membrane (total area 0.134 m2). The water vapour transfer coefficient, k, was measured to be 4.6 × 10-7 kg m-2 s-1% RH-1 in the laboratory (temperature 294 K) and is used for design purposes. A net water vapour transfer rate of up to 1.2 × 10-6 kg s-1 was achieved in the field. This corresponds to drying a 5.7 L min-1 (0.35 m3 h-1) aerosol sample flow from 100% RH to 27% RH at 293 K (with a drying air total flow of 8.7 L min-1). The system was used outdoors from 9 May until 20 October 2010, on the mountain Brocken (51.80° N, 10.67° E, 1142 m a.s.l.) in the Harz region in central Germany. Sample air relative humidity of less than 30% was obtained 72% of the time period. The total availability of the measurement system was >94% during these five months.

  9. Aerosol size and chemical composition measurements at the Polar Environment Atmospheric Research Lab (PEARL) in Eureka, Nunavut

    Science.gov (United States)

    Hayes, P. L.; Tremblay, S.; Chang, R. Y. W.; Leaitch, R.; Kolonjari, F.; O'Neill, N. T.; Chaubey, J. P.; AboEl Fetouh, Y.; Fogal, P.; Drummond, J. R.

    2016-12-01

    This study presents observations of aerosol chemical composition and particle number size distribution at the Polar Environment Atmospheric Research Laboratory (PEARL) in the Canadian High Arctic (80N, 86W). The current aerosol measurement program at PEARL has been ongoing for more than a year providing long-term observations of Arctic aerosol size distributions for both coarse and fine modes. Particle nucleation events were frequently observed during the summers of 2015 and 2016. The size distribution data are also compared against similar measurements taken at the Alert Global Atmospheric Watch Observatory (82N, 62W) for July and August 2015. The nucleation events are correlated at the two sites, despite a distance of approximately 500 km, suggesting regional conditions favorable for particle nucleation and growth during this period. Size resolved chemical composition measurements were also carried out using an aerosol mass spectrometer. The smallest measured particles between 40 and 60 nm are almost entirely organic aerosol (OA) indicating that the condensation of organic vapors is responsible for particle growth events and possibly particle nucleation. This conclusion is further supported by the relatively high oxygen content of the OA, which is consistent with secondary formation of OA via atmospheric oxidation.Lastly, surface measurements of the aerosol scattering coefficient are compared against the coefficient values calculated using Mie theory and the measured aerosol size distribution. Both the actual and the calculated scattering coefficients are then compared to sun photometer measurements to understand the relationship between surface and columnar aerosol optical properties. The measurements at PEARL provide a unique combination of surface and columnar data sets on aerosols in the High Arctic, a region where such measurements are scarce despite the important impact of aerosols on Arctic climate.PEARL research is supported by the Natural Sciences and

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

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, Paul

    2011-12-10

    Soot particles are generated by incomplete combustion of fossil and biomass fuels. Through direct effects clear air aerosols containing black carbon (BC) such as soot aerosols, absorb incoming light heating the atmosphere, while most other aerosols scatter light and produce cooling. Even though BC represents only 1-2% of the total annual emissions of particulate mass to the atmosphere, it has been estimated that the direct radiative effect of BC is the second-most important contributor to global warming after absorption by CO2. Ongoing studies continue to underscore the climate forcing importance of black carbon. However, estimates of the radiative effects of black carbon on climate remain highly uncertain due to the complexity of particles containing black carbon. Quantitative measurement of BC is challenging because BC often occurs in highly non-spherical soot particles of complex morphology. Freshly emitted soot particles are typically fractal hydrophobic aggregates. The aggregates consist of black carbon spherules with diameters typically in the range of about 15-40 nm, and they are usually coated by adsorbed polyaromatic hydrocarbons (PAHs) produced during combustion. Diesel-generated soot particles are often emitted with an organic coating composed primarily of lubricating oil and unburned fuel, as well as well as PAH compounds. Sulfuric acid has also been detected in diesel and aircraft-emitted soot particles. In the course of aging, these particle coatings may be substantially altered by chemical reactions and/or the deposition of other materials. Such processes transform the optical and CCN properties of the soot aerosols in ways that are not yet well understood. Our work over the past seven years consisted of laboratory research, instrument development and characterization, and field studies with the central focus of improving our understanding of the black carbon aerosol climate impacts. During the sixth year as well as during this seventh year (no

  11. Factors controlling the solubility of trace metals in atmospheric aerosols over the Eastern Mediterranean

    Science.gov (United States)

    Nikolaou, Panagiota; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2015-04-01

    Atmospheric input of aerosols is recognized, as an important source of nutrients, for the oceans. The chemical interactions between aerosols and varying composition of air masses lead to different coating of their surfaces with sulfate, nitrate and organic compounds, increasing their solubility and their role as a carrier of nutrients and pollutants in ecosystems. Recent works have highlighted that atmospheric inputs of nutrients and trace metals can considerably influence the marine ecosystem functioning at semi-enclosed or enclosed water bodies such as the eastern Mediterranean. The current work aims to determine the sources and the factors controlling the variability of nutrients in the eastern Mediterranean. Special focus has been given on trace elements solubility, considered either as key nutrients for phytoplankton growth such as iron (Fe), phosphorus (P) or inhibitors such as copper (Cu). This has been accomplished by analyzing size segregated aerosol samples collected at the background site of Finokalia in Crete for an entire year. Phosphorus concentrations indicate important increases in air masses influenced both by anthropogenic activities in the northeast European countries and by dust outbreaks. The last is confirmed by the correlation observed between total P and dust concentrations and by the air mass backward trajectories computed by running the NOAA Hysplit Model (Hybrid Single - Particle Langrangian Integrated Trajectory (http://www.arl.noaa.gov/ready/hysplit4.html). Overall 73% of total P has been found to be associated with anthropogenic sources. The solubility of P and Fe has been found to be closely related to the acidity (pH) and dust amount in aerosols. The aerosol pH was predicted using thermodynamic modeling (ISORROPIA-II), meteorological observations (RH, T), and gas/particle observations. More specifically P and Fe solubility appears to be inversely related to the crustal elements levels, while it increases in acidic environment. The

  12. The global impact of the transport sectors on atmospheric aerosol: simulations for year 2000 emissions

    Directory of Open Access Journals (Sweden)

    M. Righi

    2013-10-01

    Full Text Available We use the EMAC (ECHAM/MESSy Atmospheric Chemistry global model with the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications to quantify the impact of transport emissions (land transport, shipping and aviation on the global aerosol. We consider a present-day (2000 scenario according to the CMIP5 (Climate Model Intercomparison Project Phase 5 emission data set developed in support of the IPCC (Intergovernmental Panel on Climate Change Fifth Assessment Report. The model takes into account particle mass and number emissions: The latter are derived from mass emissions under different assumptions on the size distribution of particles emitted by the three transport sectors. Additional sensitivity experiments are performed to quantify the effects of the uncertainties behind such assumptions. The model simulations show that the impact of the transport sectors closely matches the emission patterns. Land transport is the most important source of black carbon (BC pollution in the USA, Europe and the Arabian Peninsula, contributing up to 60–70% of the total surface-level BC concentration in these regions. Shipping contributes about 40–60% of the total aerosol sulfate surface-level concentration along the most-traveled routes of the northern Atlantic and northern Pacific oceans, with a significant impact (~ 10–20% along the coastlines. Aviation mostly affects aerosol number, contributing about 30–40% of the particle number concentration in the northern midlatitudes' upper troposphere (7–12 km, although significant effects are also simulated at the ground, due to the emissions from landing and take-off cycles. The transport-induced perturbations to the particle number concentrations are very sensitive to the assumptions on the size distribution of emitted particles, with the largest uncertainties (about one order of magnitude obtained for the land transport sector. The simulated climate impacts, due to

  13. Massive-scale aircraft observations of giant sea-salt aerosol particle size distributions in atmospheric marine boundary layers

    Science.gov (United States)

    Jensen, J. B.

    2015-12-01

    iant sea-salt aerosol particles (dry radius, rd > 0.5 μm) occur nearly everywhere in the marine boundary layer and frequently above. This study presents observations of atmospheric sea-salt size distributions in the range 0.7 Chile and the 2011 ICE-T in the Caribbean. In each deployment, size distributions using hundreds of slides are used to relate fitted log-normal size distributions parameters to wind speed, altitude and other atmospheric conditions. The size distributions provide a unique observational set for initializing cloud models with coarse-mode aerosol particle observations for marine atmospheres.

  14. The Aerosol Index and Land Cover Class Based Atmospheric Correction Aerosol Optical Depth Time Series 1982–2014 for the SMAC Algorithm

    Directory of Open Access Journals (Sweden)

    Emmihenna Jääskeläinen

    2017-10-01

    Full Text Available Atmospheric effects, especially aerosols, are a significant source of uncertainty for optical remote sensing of surface parameters, such as albedo. Also to achieve a homogeneous surface albedo time series, the atmospheric correction has to be homogeneous. However, a global homogeneous aerosol optical depth (AOD time series covering several decades did not previously exist. Therefore, we have constructed an AOD time series 1982–2014 using aerosol index (AI data from the satellite measurements of the Total Ozone Mapping Spectrometer (TOMS and the Ozone Monitoring Instrument (OMI, together with the Solar zenith angle and land use classification data. It is used as input for the Simplified Method for Atmospheric Correction (SMAC algorithm when processing the surface albedo time series CLARA-A2 SAL (the Surface ALbedo from the Satellite Application Facility on Climate Monitoring project cLoud, Albedo and RAdiation data record, the second release. The surface reflectance simulations using the SMAC algorithm for different sets of satellite-based AOD data show that the aerosol-effect correction using the constructed TOMS/OMI based AOD data is comparable to using other satellite-based AOD data available for a shorter time range. Moreover, using the constructed TOMS/OMI based AOD as input for the atmospheric correction typically produces surface reflectance [-20]values closer to those obtained using in situ AOD values than when using other satellite-based AOD data.

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

    Science.gov (United States)

    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

  16. Marine sediment tolerances for remote sensing of atmospheric aerosols over water

    Science.gov (United States)

    Whitlock, C. H.

    1982-01-01

    In surveying the literature, it is pointed out that there is a need to quantify the turbidity below which reflectance from the water column is negligible in comparison with atmospheric effects to allow the monitoring of aerosol optical depth over water bodies. Data that partially satisfy this need are presented. Laboratory measurements of reflectance upwelled from the water column are given for mixtures with various types of sediment at wavelengths between 400 and 1600 nm. The results of the study described here are a quantitative endorsement of the recommendations of Morell and Gordon (1980).

  17. Particle size distribution of major inorganic species in atmospheric aerosols from Majorca (Spain).

    Science.gov (United States)

    Mateu, J.; Forteza, R.; Cerdà, V.; Colom-Altés, M.

    1995-09-01

    Atmospheric aerosols collected by means of a cascade impaction system at the campus of the University of the Balearic Islands (Majorca, Spain) from November 1993 to February 1994 were analysed for chloride, nitrate, sulphate, ammonium, calcium, magnesium, sodium and potassium. Based on particle size distribution, the species studied were classified into three groups: (a) concentration decrease with particle size (sulphate and ammonium), (b) concentration increase with particle size (chloride, calcium, magnesium and sodium), and ( c) independent of particle size (nitrate and potassium). A principal component analysis (PCA) revealed a clear relationship between particle size and analyte origin. Also, the origin of sulphate and potassium fine and coarse particles was found to be different.

  18. Evaluation of Vapor Pressure Estimation Methods for Use in Simulating the Dynamic of Atmospheric Organic Aerosols

    Directory of Open Access Journals (Sweden)

    A. J. Komkoua Mbienda

    2013-01-01

    Lee and Kesler (LK, and Ambrose-Walton (AW methods for estimating vapor pressures ( are tested against experimental data for a set of volatile organic compounds (VOC. required to determine gas-particle partitioning of such organic compounds is used as a parameter for simulating the dynamic of atmospheric aerosols. Here, we use the structure-property relationships of VOC to estimate . The accuracy of each of the aforementioned methods is also assessed for each class of compounds (hydrocarbons, monofunctionalized, difunctionalized, and tri- and more functionalized volatile organic species. It is found that the best method for each VOC depends on its functionality.

  19. Atmospheric Aerosol Sampling with Unmanned Aircraft Systems (UAS) in Alaska: Instrument Development, Payload Integration, and Measurement Campaigns

    Science.gov (United States)

    Barberie, S. R.; Saiet, E., II; Hatfield, M. C.; Cahill, C. F.

    2014-12-01

    Atmospheric aerosols remain one of biggest variables in understanding global climate. The number of feedback loops involved in aerosol processes lead to nonlinear behavior at the systems level, making confident modeling and prediction difficult. It is therefore important to ground-truth and supplement modeling efforts with rigorous empirical measurements. To this end, the Alaska Center for Unmanned Aircraft Systems Integration (ACUASI) at the University of Alaska Fairbanks has developed a new cascade DRUM-style impactor to be mounted aboard a variety of unmanned aircraft and work in tandem with an optical particle counter for the routine collection of atmospheric aerosols. These UAS-based aerosol samplers will be employed for measurement campaigns in traditionally hazardous conditions such as volcanic plumes and over forest fires. Here we report on the development and laboratory calibration of the new instrument, the integration with UAS, and the vertical profiling campaigns being undertaken.

  20. Palmitic Acid on Salt Subphases and in Mixed Monolayers of Cerebrosides: Application to Atmospheric Aerosol Chemistry

    Directory of Open Access Journals (Sweden)

    Ellen M. Adams

    2013-10-01

    Full Text Available Palmitic acid (PA has been found to be a major constituent in marine aerosols, and is commonly used to investigate organic containing atmospheric aerosols, and is therefore used here as a proxy system. Surface pressure-area isotherms (π-A, Brewster angle microscopy (BAM, and vibrational sum frequency generation (VSFG were used to observe a PA monolayer during film compression on subphases of ultrapure water, CaCl2 and MgCl2 aqueous solutions, and artificial seawater (ASW. π-A isotherms indicate that salt subphases alter the phase behavior of PA, and BAM further reveals that a condensation of the monolayer occurs when compared to pure water. VSFG spectra and BAM images show that Mg2+ and Ca2+ induce ordering of the PA acyl chains, and it was determined that the interaction of Mg2+ with the monolayer is weaker than Ca2+. π-A isotherms and BAM were also used to monitor mixed monolayers of PA and cerebroside, a simple glycolipid. Results reveal that PA also has a condensing effect on the cerebroside monolayer. Thermodynamic analysis indicates that attractive interactions between the two components exist; this may be due to hydrogen bonding of the galactose and carbonyl headgroups. BAM images of the collapse structures show that mixed monolayers of PA and cerebroside are miscible at all surface pressures. These results suggest that the surface morphology of organic-coated aerosols is influenced by the chemical composition of the aqueous core and the organic film itself.

  1. Single-particle chemical characterization and source apportionment of iron-containing atmospheric aerosols in Asian outflow

    Science.gov (United States)

    Furutani, Hiroshi; Jung, Jinyoung; Miura, Kazuhiko; Takami, Akinori; Kato, Shungo; Kajii, Yoshizumi; Uematsu, Mitsuo

    2011-09-01

    Using a single-particle mass spectrometer, the size and chemical composition of individual Fe-containing atmospheric aerosols (Fe aerosols) with diameter from 100 to 1800 nm were characterized during Asian outflow season (spring of 2008) in Okinawa Island, Japan and their sources were determined. Fe aerosols were classified into five unique particle types which were mixed with specific compound(s) and related to their sources (crustal, fly ash/K-biomass burning, elemental carbon, metals, and vanadium). Particle number-based contribution of the crustal particle type, which has been thought to be the main source of aerosol Fe, was quite small (2 ˜ 10%) in all size ranges, while anthropogenic Fe aerosols were the dominant contributor in this study. Fly ash/K-biomass burning type was the most abundant particle types, which contributed ˜50%. Metals and elemental carbon types contributed ˜20% and ˜10%, respectively. Contribution of vanadium type was variable (5 ˜ 50%), which is attributed to ship emission. The frequent appearance of lithium ion peak in the fly ash/K-biomass burning type strongly suggests that large fraction of the type is coal combustion origin, reflecting high coal usage in China. These results show that anthropogenic sources contributes significant portion of Fe aerosols in Asian outflow. Excluding the vanadium type, relative contribution of the remaining four particle types was constant over the course of study, which remained even when the total concentration of Fe aerosols changed and fraction of the Fe aerosols among atmospheric aerosols decreased significantly by the switch of air mass type into marine type. We concluded that the observed constant relative abundance reflected the relative source strength of Fe aerosols in Asian outflow, particularly emphasizing the importance of coal combustion source in East Asia.

  2. An Observing System Simulation Experiment (OSSE) Investigating the OMI Aerosol Products Using Simulated Aerosol and Atmospheric Fields from the NASA GEOS-5 Model

    Science.gov (United States)

    Colarco, P. R.; Gasso, S.; Jethva, H. T.; Buchard, V.; Ahn, C.; Torres, O.; daSilva, A.

    2016-12-01

    Output from the NASA Goddard Earth Observing System, version 5 (GEOS-5) Earth system model is used to simulate the top-of-atmosphere 354 and 388 nm radiances observed by the Ozone Monitoring Instrument (OMI) onboard the Aura spacecraft. The principle purpose of developing this simulator tool is to compute from the modeled fields the so-called OMI Aerosol Index (AI), which is a more fundamental retrieval product than higher level products such as the aerosol optical depth (AOD) or absorbing aerosol optical depth (AAOD). This lays the groundwork for eventually developing a capability to assimilate either the OMI AI or its radiances, which would provide further constraint on aerosol loading and absorption properties for global models. We extend the use of the simulator capability to understand the nature of the OMI aerosol retrieval algorithms themselves in an Observing System Simulation Experiment (OSSE). The simulated radiances are used to calculate the AI from the modeled fields. These radiances are also provided to the OMI aerosol algorithms, which return their own retrievals of the AI, AOD, and AAOD. Our assessment reveals that the OMI-retrieved AI can be mostly harmonized with the model-derived AI given the same radiances provided a common surface pressure field is assumed. This is important because the operational OMI algorithms presently assume a fixed pressure field, while the contribution of molecular scattering to the actual OMI signal in fact responds to the actual atmospheric pressure profile, which is accounted for in our OSSE by using GEOS-5 produced atmospheric reanalyses. Other differences between the model and OMI AI are discussed, and we present a preliminary assessment of the OMI AOD and AAOD products with respect to the known inputs from the GEOS-5 simulation.

  3. Bistatic imaging lidar measurements of aerosols, fogs, and clouds in the lower atmosphere

    Science.gov (United States)

    Lin, Jinming; Mishima, Hidetsugu; Kawahara, Takuya D.; Saito, Yasunori; Nomura, Akio; Yamaguchi, Kenji; Morikawa, Kimio

    1998-08-01

    We have been developing a bistatic imaging lidar using a high sensitive CCD camera with an image intensifier as a high speed shutter for measuring spatial distributions of aerosols, fogs and clouds in the lower atmosphere at daytime as well as at nighttime. The bistatic imaging lidar was applied to two field observation campaigns. One was made cooperatively with a wind profiler and a radiosonde at Moriya (36 km north of Tokyo) for five days from May 26 to 30, 1997 and another cooperatively with a monostatic lidar at Hakuba alpine ski area of Nagano for 10 days from February 7 to 16, 1998 during the period of the 18th Winter Olympic Games in Japan. We report the results obtained at both campaigns and discuss the ability of this system in measuring the meteorological features of the local lower atmosphere under different conditions.

  4. Soot Aerosol In The Atmosphere: Pole-to-Pole Distribution And Contributions by Aircraft

    Science.gov (United States)

    Pueschel, R. F.; Verma, S.; Howard, S. D.; Ferry, G. V.; Goodman, J.; Allen, D. A.; Strawa, Anthony W. (Technical Monitor)

    1995-01-01

    Interest in the distribution of black carbon (soot) aerosol (BCA) in the atmosphere is warranted for the following reasons: (1) BCA has the highest absorption cross section of any compound known, thus it can absorb solar radiation to cause atmospheric warming; (2) BCA is a strong adsorber of gases, thus it can catalyze heterogeneous chemical reactions to modify the chemical composition of the atmosphere; (3) If aircraft emission is the major source of atmospheric BCA, it can serve as an atmospheric tracer of aircraft exhaust. We collect BCA particles greater than or equal to 0.02 micrometer diameter by wires mounted on both the DC-8 and ER-2 aircraft. After return to the laboratory, the wires are examined with a field emission scanning electron microscope to identify BCA particles by their characteristic morphology. Typically, BCA exists in the atmosphere as small particles of complex morphology. The particle sizes at the source are measured in tens of Angstrom units; after a short residence time in the atmosphere, individual particles coalesce to loosely packed agglomerates of typical dimensions 0.01 to 0.1 micrometer. We approximate the size of each BCA aggregate by that of a sphere of equivalent volume. This is done by computing the volume of a sphere whose diameter is the mean between averaged minimum and maximum dimensions of the BCA particle. While this procedure probably underestimates the actual surface area, it permits us to compare BCA size distributions among themselves and with other types of aerosols. When statistically justified, we fit lognormal distributions to the data points to determine number concentrations, geometric mean radii, standard deviations, BCA surface areas and volumes. Results to date permit the following conclusions: (1) BCA concentration in the northern stratosphere averages 0.6 ng per cubic meters. This amount is one part in 10(exp 4) after a volcanic eruption (e.g., Pinatubo) increasing to about one percent during volcanic

  5. The importance of plume rise on the concentrations and atmospheric impacts of biomass burning aerosol

    Directory of Open Access Journals (Sweden)

    C. Walter

    2016-07-01

    Full Text Available We quantified the effects of the plume rise of biomass burning aerosol and gases for the forest fires that occurred in Saskatchewan, Canada, in July 2010. For this purpose, simulations with different assumptions regarding the plume rise and the vertical distribution of the emissions were conducted. Based on comparisons with observations, applying a one-dimensional plume rise model to predict the injection layer in combination with a parametrization of the vertical distribution of the emissions outperforms approaches in which the plume heights are initially predefined. Approximately 30 % of the fires exceed the height of 2 km with a maximum height of 8.6 km. Using this plume rise model, comparisons with satellite images in the visible spectral range show a very good agreement between the simulated and observed spatial distributions of the biomass burning plume. The simulated aerosol optical depth (AOD with data of an AERONET station is in good agreement with respect to the absolute values and the timing of the maximum. Comparison of the vertical distribution of the biomass burning aerosol with CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation retrievals also showed the best agreement when the plume rise model was applied. We found that downwelling surface short-wave radiation below the forest fire plume is reduced by up to 50 % and that the 2 m temperature is decreased by up to 6 K. In addition, we simulated a strong change in atmospheric stability within the biomass burning plume.

  6. Measuring atmospheric aerosols of organic origin on multirotor Unmanned Aerial Vehicles (UAVs).

    Science.gov (United States)

    Crazzolara, Claudio; Platis, Andreas; Bange, Jens

    2017-04-01

    In-situ measurements of the spatial distribution and transportation of atmospheric organic particles such as pollen and spores are of great interdisciplinary interest such as: - In agriculture to investigate the spread of transgenetic material, - In paleoclimatology to improve the accuracy of paleoclimate models derived from pollen grains retrieved from sediments, and - In meteorology/climate research to determine the role of spores and pollen acting as nuclei in cloud formation processes. The few known state of the art in-situ measurement systems are using passive sampling units carried by fixed wing UAVs, thus providing only limited spatial resolution of aerosol concentration. Also the passively sampled air volume is determined with low accuracy as it is only calculated by the length of the flight path. We will present a new approach, which is based on the use of a multirotor UAV providing a versatile platform. On this UAV an optical particle counter in addition to a particle collecting unit, e.g. a conventional filter element and/or a inertial mass separator were installed. Both sampling units were driven by a mass flow controlled blower. This allows not only an accurate determination of the number and size concentration, but also an exact classification of the type of collected aerosol particles as well as an accurate determination of the sampled air volume. In addition, due to the application of a multirotor UAV with its automated position stabilisation system, the aerosol concentration can be measured with a very high spatial resolution of less than 1 m in all three dimensions. The combination of comprehensive determination of number, type and classification of aerosol particles in combination with the very high spatial resolution provides not only valuable progress in agriculture, paleoclimatology and meteorology, but also opens up the application of multirotor UAVs in new fields, for example for precise determination of the mechanisms of generation and

  7. Aerosol hygroscopicity and its impact on atmospheric visibility and radiative forcing in Guangzhou during the 2006 PRIDE-PRD campaign

    Science.gov (United States)

    Liu, Xingang; Zhang, Yuanhang; Cheng, Yafang; Hu, Min; Han, Tingting

    2012-12-01

    The objective of this study is to quantify the relation of aerosol chemical compositions and optical properties, and to assess the impact of relative humidity (RH) on atmospheric visibility and aerosol direct radiative forcing (ADRF). Mass concentration and size distribution of aerosol chemical compositions as well as aerosol optical properties were concurrently measured at Guangzhou urban site during the PRD (Pearl River Delta) campaign from 1 to 31 July, 2006. Gaseous pollutant NO2 and meteorological parameter were simultaneously monitored. Compared with its dry condition, atmospheric ambient extinction coefficient σext(RH) averagely increased about 51% and atmospheric visibility deceased about 35%, among which RH played an important role on the optical properties of water soluble inorganic salts. (NH4)2SO4 is the most important component responsible for visibility degradation at Guangzhou. In addition, the asymmetry factor g increased from 0.64 to 0.74 with the up-scatter fraction β decreasing from 0.24 to 0.19 when RH increasing from 40% to 90%. At 80% RH, the ADRF increased about 280% compared to that at dry condition and it averagely increased about 100% during the campaign under ambient conditions. It can be inferred that aerosol water content is a key factor and could not be ignored in assessing the role of aerosols in visibility impairment and radiative forcing, especially in the regions with high RH.

  8. Reactivity of liquid and semisolid secondary organic carbon with chloride and nitrate in atmospheric aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bingbing [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); O' Brien, Rachel E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of the Pacific, Stockton, CA (United States); Kelly, Stephen T. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shilling, John E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moffet, Ryan C. [Univ. of the Pacific, Stockton, CA (United States); Gilles, Mary K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Laskin, Alexander [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-05-14

    Constituents of secondary organic carbon (SOC) in atmospheric aerosols are often mixed with inorganic components and compose a significant mass fraction of fine particulate matter in the atmosphere. Interactions between SOC and other condensed-phase species are not well understood. Here, we investigate the reactions of liquid-like and semi-solid SOC from ozonolysis of limonene (LSOC) and α-pinene (PSOC) with NaCl using a set of complementary micro-spectroscopic analyses. These reactions result in chloride depletion in the condensed phase, release of gaseous HCl, and formation of organic salts. The reactions attributed to acid displacement by SOC acidic components are driven by the high volatility of HCl. Similar reactions can take place in SOC/NaNO₃ particles. The results show that an increase in SOC mass fraction in the internally mixed SOC/NaCl particles leads to higher chloride depletion. Glass transition temperatures and viscosity of PSOC were estimated for atmospherically relevant conditions. Data show that the reaction extent depends on SOC composition, particle phase state and viscosity, mixing state, temperature, relative humidity (RH), and reaction time. LSOC shows slightly higher potential to deplete chloride than PSOC. Higher particle viscosity at low temperatures and RH can hinder these acid displacement reactions. Formation of organic salts from these overlooked reactions can alter particle physiochemical properties and may affect their reactivity and ability to act as cloud condensation and ice nuclei. The release and potential recycling of HCl and HNO₃ from reacted aerosol particles may have important implications for atmospheric chemistry.

  9. Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation.

    Science.gov (United States)

    Kirkby, Jasper; Curtius, Joachim; Almeida, João; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Franchin, Alessandro; Gagné, Stéphanie; Ickes, Luisa; Kürten, Andreas; Kupc, Agnieszka; Metzger, Axel; Riccobono, Francesco; Rondo, Linda; Schobesberger, Siegfried; Tsagkogeorgas, Georgios; Wimmer, Daniela; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Downard, Andrew; Ehn, Mikael; Flagan, Richard C; Haider, Stefan; Hansel, Armin; Hauser, Daniel; Jud, Werner; Junninen, Heikki; Kreissl, Fabian; Kvashin, Alexander; Laaksonen, Ari; Lehtipalo, Katrianne; Lima, Jorge; Lovejoy, Edward R; Makhmutov, Vladimir; Mathot, Serge; Mikkilä, Jyri; Minginette, Pierre; Mogo, Sandra; Nieminen, Tuomo; Onnela, Antti; Pereira, Paulo; Petäjä, Tuukka; Schnitzhofer, Ralf; Seinfeld, John H; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Vanhanen, Joonas; Viisanen, Yrjo; Vrtala, Aron; Wagner, Paul E; Walther, Hansueli; Weingartner, Ernest; Wex, Heike; Winkler, Paul M; Carslaw, Kenneth S; Worsnop, Douglas R; Baltensperger, Urs; Kulmala, Markku

    2011-08-24

    Atmospheric aerosols exert an important influence on climate through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100-1,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H(2)SO(4)-H(2)O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.

  10. The critical assessment of vapour pressure estimation methods for use in modelling the formation of atmospheric organic aerosol

    Directory of Open Access Journals (Sweden)

    M. H. Barley

    2010-01-01

    Full Text Available A selection of models for estimating vapour pressures have been tested against experimental data for a set of compounds selected for their particular relevance to the formation of atmospheric aerosol by gas-liquid partitioning. The experimental vapour pressure data (all <100 Pa of 45 multifunctional compounds provide a stringent test of the estimation techniques, with a recent complex group contribution method providing the best overall results. The effect of errors in vapour pressures upon the formation of organic aerosol by gas-liquid partitioning in an atmospherically relevant example is also investigated. The mass of organic aerosol formed under typical atmospheric conditions was found to be very sensitive to the variation in vapour pressure values typically present when comparing estimation methods.

  11. Clays as mineral dust aerosol: An integrated approach to studying climate, atmospheric chemistry, and biogeochemical effects of atmospheric clay minerals in an undergraduate research laboratory

    Science.gov (United States)

    Hatch, C. D.; Crane, C. C.; Harris, K. J.; Thompson, C. E.; Miles, M. K.; Weingold, R. M.; Bucuti, T.

    2011-12-01

    Entrained mineral dust aerosol accounts for 45% of the global annual atmospheric aerosol load and can have a significant influence on important environmental issues, including climate, atmospheric chemistry, cloud formation, biogeochemical processes, visibility, and human health. 70% of all mineral aerosol mass originating from Africa consists of layered aluminosilicates, including illite, kaolinite, and montmorillonite clays. Clay minerals are a largely neglected component of mineral aerosol, yet they have unique physiochemical properties, including a high reactive surface area, large cation exchange capacities, small particle sizes, and a relatively large capacity to take up adsorbed water, resulting in expansion of clay layers (and a larger reactive surface area for heterogeneous interactions) in some cases. An integrated laboratory research approach has been implemented at Hendrix College, a Primarily Undergraduate Institution, in which undergraduate students are involved in independent and interdisciplinary research projects that relate the chemical aging processes (heterogeneous chemistry) of clay minerals as a major component of mineral aerosol to their effects on climate (water adsorption), atmospheric chemistry (trace gas uptake), and biogeochemistry (iron dissolution and phytoplankton biomarker studies). Preliminary results and future directions will be reported.

  12. Modelling atmospheric aerosol backscatter at CO2 laser wavelengths. I - Aerosol properties, modeling techniques, and associated problems. II - Modeled values in the atmosphere. III - Effects of changes in wavelength and ambient conditions

    Science.gov (United States)

    Kent, G.S.; Yue, G. K.; Farrukh, U. O.; Deepak, A.

    1983-01-01

    The various methods of calculating the atmospheric aerosol backscattering function, beta(CO2), both from measured aerosol characteristics and from optical measurements made at other wavelengths, are discussed in detail, with limits placed on their accuracy. The most significant factor in determining beta(CO2) is found to be the aerosol size distribution and concentration; this should be known accurately for particle radii up to at least 1 micron for stratospheric particles and 5 microns for tropospheric particles. Results are then presented from the modeling of the aerosol backscattering function at a wavelength of 10.6 microns in the lowest 20 km of the atmosphere. It is found that beta(CO2) varies from 10 to the -6th per m per sr in the planetary boundary layer to less than 10 to the -11th per m per sr in the stratosphere. It is next shown that, with the exception of (NH4)2SO4-containing aerosols, whose size distributions have relatively large numbers of small particles, the variation of backscattering with CO2 wavelength is less than a factor of approximately 3. For such (NH4)2SO4 aerosol distributions, however, the variation of backscatter function with CO2 wavelengths between 9.1 and 11.1 microns may reach one order of magnitude.

  13. Response of middle atmosphere chemistry and dynamics to volcanically elevated sulfate aerosol: Three-dimensional coupled model simulations

    Science.gov (United States)

    Al-Saadi, Jassim A.; Pierce, R. Bradley; Fairlie, T. Duncan; Kleb, Mary M.; Eckman, Richard S.; Grose, William L.; Natarajan, Murali; Olson, Jennifer R.

    2001-11-01

    The NASA Langley Research Center Interactive Modeling Project for Atmospheric Chemistry and Transport (IMPACT) model has been used to examine the response of the middle atmosphere to a large tropical stratospheric injection of sulfate aerosol, such as that following the June 1991 eruption of Mount Pinatubo. The influence of elevated aerosol on heterogeneous chemical processing was simulated using a three-dimensional climatology of surface area density (SAD)developed using observations made from the Halogen Occultation Experiment, Stratospheric Aerosol and Gas Experiment II, and Stratospheric Aerosol Measurement satellite instruments beginning in June 1991. Radiative effects of the elevated aerosol were represented by monthly mean zonally averaged heating perturbations obtained from a study conducted with the European Center/Hamburg (ECHAM4) general circulation model combined with an observationally derived set of aerosol parameters. Two elevated-aerosol simulations were integrated for 31/2 years following the volcanic injection. One simulation included only the aerosol radiative perturbation, and one simulation included both the radiative perturbation and the elevated SAD. These perturbation simulations are compared with multiple-year control simulations to isolate relative contributions of transport and heterogeneous chemical processing. Significance of modeled responses is assessed through comparison with interannual variability. Dynamical and photochemical contributions to ozone decreases are of comparable magnitude. Important stratospheric chemical/dynamical feedback effects are shown, as ozone reductions modulate aerosol-induced heating by up to 10% in the lower stratosphere and 25% in the middle stratosphere. Dynamically induced changes in chemical constituents which propagate into the upper stratosphere are still pronounced at the end of the simulations.

  14. The global impact of the transport sectors on atmospheric aerosol in 2030 – Part 1: Land transport and shipping

    Directory of Open Access Journals (Sweden)

    M. Righi

    2015-01-01

    Full Text Available Using the EMAC (ECHAM/MESSy Atmospheric Chemistry global climate-chemistry model coupled to the aerosol module MADE (Modal Aerosol Dynamics model for Europe, adapted for global applications, we simulate the impact of land transport and shipping emissions on global atmospheric aerosol and climate in 2030. Future emissions of short-lived gas and aerosol species follow the four Representative Concentration Pathways (RCPs designed in support of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. We compare the resulting 2030 land-transport- and shipping-induced aerosol concentrations to the ones obtained for the year 2000 in a previous study with the same model configuration. The simulations suggest that black carbon and aerosol nitrate are the most relevant pollutants from land transport in 2000 and 2030 and their impacts are characterized by very strong regional variations during this time period. Europe and North America experience a decrease in the land-transport-induced particle pollution, although in these regions this sector remains a major source of surface-level pollution in 2030 under all RCPs. In Southeast Asia, however, a significant increase is simulated, but in this region the surface-level pollution is still controlled by other sources than land transport. Shipping-induced air pollution is mostly due to aerosol sulfate and nitrate, which show opposite trends towards 2030. Sulfate is strongly reduced as a consequence of sulfur reduction policies in ship fuels in force since 2010, while nitrate tends to increase due to the excess of ammonia following the reduction in ammonium sulfate. The aerosol-induced climate impact of both sectors is dominated by aerosol-cloud effects and is projected to decrease between 2000 and 2030, nevertheless still contributing a significant radiative forcing to Earth's radiation budget.

  15. Modeling coastal aerosol transport and effects of surf-produced aerosols on processes in the marine atmospheric boundary layer

    NARCIS (Netherlands)

    Vignati, E.; Leeuw, G. de; Berkowicz, R.

    2001-01-01

    The Coastal Aerosol Transport (CAT) model was developed to study the evolution of aerosol particle size distributions and composition in the coastal environment. The model simulates such processes as particle production at the sea surface, mixing of particles through the boundary layer by turbulent

  16. The Dedicated Aerosol Retrieval Experiment (DARE): scientific requirements for a dedicated satellite instrument to measure atmospheric aerosols

    NARCIS (Netherlands)

    Decae, R.; Courrèges-Lacoste, G.B.; Leeuw, G. de

    2004-01-01

    DARE (Dedicated Aerosol Retrieval Experiment) is a study to design an instrument for accurate remote sensing of aerosol properties from space. DARE combines useful properties of several existing instruments like TOMS, GOME, ATSR and POLDER. It has a large wavelength range, 330 to 1000 nm, to

  17. Origins and composition of fine atmospheric carbonaceous aerosol in the Sierra Nevada Mountains, California

    Directory of Open Access Journals (Sweden)

    D. R. Worton

    2011-10-01

    Full Text Available In this paper we report chemically resolved measurements of organic aerosol (OA and related tracers during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX at the Blodgett Forest Research Station, California from 15 August–10 October 2007. OA contributed the majority of the mass to the fine atmospheric particles and was predominately oxygenated (OOA. The highest concentrations of OA were during sporadic wildfire influence when aged plumes were impacting the site. In situ measurements of particle phase molecular markers were dominated by secondary compounds and along with gas phase compounds could be categorized into six factors or sources: (1 aged biomass burning emissions and oxidized urban emissions, (2 oxidized urban emissions (3 oxidation products of monoterpene emissions, (4 monoterpene emissions, (5 anthropogenic emissions and (6 local methyl chavicol emissions and oxidation products. There were multiple biogenic components that contributed to OA at this site whose contributions varied diurnally, seasonally and in response to changing meteorological conditions, e.g. temperature and precipitation events. Concentrations of isoprene oxidation products were larger when temperatures were higher during the first half of the campaign (15 August–12 September due to more substantial emissions of isoprene and enhanced photochemistry. The oxidation of methyl chavicol, an oxygenated terpene emitted by ponderosa pine trees, contributed similarly to OA throughout the campaign. In contrast, the abundances of monoterpene oxidation products in the particle phase were greater during the cooler conditions in the latter half of the campaign (13 September–10 October, even though emissions of the precursors were lower, although the mechanism is not known. OA was correlated with the anthropogenic tracers 2-propyl nitrate and carbon monoxide (CO, consistent with previous observations, while being comprised of mostly non-fossil carbon

  18. Spatiotemporal patterns of correlation between atmospheric nitrogen dioxide and aerosols over South Asia

    Science.gov (United States)

    ul-Haq, Zia; Tariq, Salman; Ali, Muhammad

    2017-10-01

    An accurate knowledge is needed on the complex relation between atmospheric trace gasses and aerosol variability and their sources to explain trace gases-aerosols-climate interaction and next-generation modeling of climate change and air quality. In this regard, we have used tropospheric Nitrogen Dioxide (NO2), Aerosol Optical Depth (AOD) and Angstrom Exponent (AE) obtained from satellite-based Ozone Monitoring Instrument (OMI)/Aura and Moderate-Resolution Imaging Spectroradiometer (MODIS)/Aqua over South Asia. NO2-AOD correlation with coefficient r = 0.49 is determined over the landmass of South Asia during 2005-2015. Yearly mean NO2-AOD correlation over South Asia shows large variations ranging from r = 0.32 to 0.86 in 2008 and 2009, respectively. The highest correlation ( r = 0.66) is seen over eastern regions of Bangladesh and India, as well as adjoining areas of western Myanmar mostly linked to anthropogenic activities. A significant correlation ( r = 0.59) associated with natural causes is found over some parts of Sistan region, located at the borders of Iran, Pakistan and Afghanistan, and adjoining territory. We find significant positive correlations for monsoon and post-monsoon seasons with r = 0.50 and r = 0.61, respectively. A linear regression on the annual correlation coefficients data suggests that NO2-AOD correlation is strengthening with an increase of 12.9% over South Asia during the study period. The spatial distribution of data slopes reveals positive trends in NO2-AOD correlation over megacities Lahore, Dhaka, Mumbai and Kolkata linked to growing anthropogenic activities. Singrauli city (India) has the highest correlation ( r = 0.62) and 35% increase in correlation coefficient value per year. A negative correlation is observed for megacity Karachi ( r = -0.37) suggesting the non-commonality of NO2 and aerosols emission sources. AE has also been used to discuss its correlation with NO2 over the areas with dominance of fine-mode aerosols.

  19. Continuous stand-alone controllable aerosol/cloud droplet dryer for atmospheric sampling

    Directory of Open Access Journals (Sweden)

    S. Sjogren

    2013-02-01

    Full Text Available We describe a general-purpose dryer designed for continuous sampling of atmospheric aerosol, where a specified relative humidity (RH of the sample flow (lower than the atmospheric humidity is required. It is often prescribed to measure the properties of dried aerosol, for instance for monitoring networks. The specific purpose of our dryer is to dry cloud droplets (maximum diameter approximately 25 μm, highly charged, up to 5 × 102 charges. One criterion is to minimise losses from the droplet size distribution entering the dryer as well as on the residual dry particle size distribution exiting the dryer. This is achieved by using a straight vertical downwards path from the aerosol inlet mounted above the dryer, and removing humidity to a dry, closed loop airflow on the other side of a semi-permeable GORE-TEX membrane (total area 0.134 m2.

    The water vapour transfer coefficient, k, was measured to be 4.6 × 10-7 kg m−2 s−1% RH−1 in the laboratory (temperature 294 K and is used for design purposes. A net water vapour transfer rate of up to 1.2 × 10-6 kg s−1 was achieved in the field. This corresponds to drying a 5.7 L min−1 (0.35 m3 h−1 aerosol sample flow from 100% RH to 27% RH at 293 K (with a drying air total flow of 8.7 L min−1. The system was used outdoors from 9 May until 20 October 2010, on the mountain Brocken (51.80° N, 10.67° E, 1142 m a.s.l. in the Harz region in central Germany. Sample air relative humidity of less than 30% was obtained 72% of the time period. The total availability of the measurement system was >94% during these five months.

  20. Dissolution process of atmospheric aerosol particles into cloud droplets; Processus de dissolution des aerosols atmospheriques au sein des gouttes d'eau nuageuses

    Energy Technology Data Exchange (ETDEWEB)

    Desboeufs, K.

    2001-01-15

    Clouds affect both climate via the role they play in the Earth's radiation balance and tropospheric chemistry since they are efficient reaction media for chemical transformation of soluble species. Cloud droplets are formed in the atmosphere by condensation of water vapour onto aerosol particles, the cloud condensation nuclei (CCN). The water soluble fraction of these CCN governs the cloud micro-physics, which is the paramount factor playing on the radiative properties of clouds. Moreover, this soluble fraction is the source of species imply in the oxidation/reduction reactions in the aqueous phase. Thus, it is of particular importance to understand the process controlling the solubilization of aerosols in the cloud droplets. The main purpose of this work is to investigate experimentally and theoretically the dissolution of particles incorporated in the aqueous phase. From the studies conducted up to now, we have identify several factors playing on the dissolution reaction of aerosols. However, the quantification of the effects of these factors is difficult since the current means of study are not adapted to the complexity of cloud systems. First, this work consisted to perform a experimental system, compound by an open flow reactor, enabling to follow the kinetic of dissolution in conditions representative of cloud. This experimental device is used to a systematic characterisation of the known factors playing on the dissolution, i.e. pH, aerosol nature, aerosol weathering... and also for the identification and the quantification of the effects of other factors: ionic strength, acid nature, clouds processes. These experiments gave quantitative results, which are used to elaborate a simple model of aerosol dissolution in the aqueous phase. This model considers the main factors playing on the dissolution and results in a general mechanism of aerosol dissolution extrapolated to the cloud droplets. (author)

  1. Impact of the smoke aerosol from Russian forest fires on the atmospheric environment over Korea during May 2003

    Science.gov (United States)

    Lee, Kwon H.; Kim, Jeong E.; Kim, Young J.; Kim, Jhoon; von Hoyningen-Huene, Wolfgang

    Extensive forest fire activities occurred in May 2003 across Siberia, Russia, particularly in the area between the Amur and Lena rivers east of Lake Baikal. These forest fires released large amounts of particulates and gases into the atmosphere, resulting in adverse effects on regional air quality and radiation budget. On certain occasions, a smoke pollution plume from these forest fires was transported through Mongolia and eastern China, down to the Korean peninsula. In this study, satellite data and ground-based radiation measurement data were analyzed to estimate the smoke aerosol's impact on the local atmospheric environment over Korea. Aerosol optical depth (AOD) values retrieved using the Bremen Aerosol Retrieval method from Moderate Resolution Imaging Spectroradiometer data were compared with those derived from ground-based radiation measurements. Large AOD values in the range 2.0-4.0 were observed on 20 May 2003 over Korea due to the influence of the long-range transported smoke aerosol plume from the Russian fires, resulting in a surface-observed short-wavelength direct aerosol radiative forcing efficiency of -90 to -200 W m -2. This smoke aerosol plume also resulted in a decrease in the solar visible irradiance of up to 57%, and increased the surface PM10 concentration by up to 258 μg m -3.

  2. Determination of saccharide markers in atmospheric aerosols. IC with subsequent pulsed amperometric detection; Bestimmung von Saccharidmarkern in atmosphaerischen Aerosolen. IC mit anschliessender gepulster amperometrischer Detektion

    Energy Technology Data Exchange (ETDEWEB)

    Wille, A.; Steinbach, A. [Metrohm International Headquarters, Herisau (Switzerland); Rick, Silke [Leibniz-Zentrum fuer Marine Tropenoekologie (ZMT), Bremen (Germany)

    2010-11-15

    The anhydrous sugars levoglucosan, mannosan and galactosan arise from the combustion of cellulose and hemicellulose. This anhydrous sugars are proven in atmospheric aerosols and are an important marker for the combustion of biomass. In contrast to this, the sugar alcohols arabitol and mannitol serve as aerosol markers for primary bio particles such as fungal spores. A fast and robust analysis method for the determination of saccharide markers in aerosols is of great interest for the chemistry of atmosphere, meteorology and health matters.

  3. Uncertainty evaluation in correlated quantities: application to elemental analysis of atmospheric aerosols;Evaluacion de la incertidumbre en cantidades correlacionadas: aplicacion al analisis elemental de aerosoles atmosfericos

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, A.; Miranda, J.; Pineda, J. C., E-mail: miranda@fisica.unam.m [UNAM, Instituto de Fisica, Circuito de la Investigacion Cientifica s/n, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-07-01

    One of the aspects that are frequently overlooked in the evaluation of uncertainty in experimental data is the possibility that the involved quantities are correlated among them, due to different causes. An example in the elemental analysis of atmospheric aerosols using techniques like X-ray Fluorescence (X RF) or Particle Induced X-ray Emission (PIXE). In these cases, the measured elemental concentrations are highly correlated, and then are used to obtain information about other variables, such as the contribution from emitting sources related to soil, sulfate, non-soil potassium or organic matter. This work describes, as an example, the method required to evaluate the uncertainty in variables determined from correlated quantities from a set of atmospheric aerosol samples collected in the Metropolitan Area of the Mexico Valley and analyzed with PIXE. The work is based on the recommendations of the Guide for the Evaluation of Uncertainty published by the International Organization for Standardization. (Author)

  4. Global measurements of coarse-mode aerosol size distributions - first results from the Atmospheric Tomography Mission (ATom)

    Science.gov (United States)

    Weinzierl, B.; Dollner, M.; Schuh, H.; Brock, C. A.; Bui, T. V.; Gasteiger, J.; Froyd, K. D.; Schwarz, J. P.; Spanu, A.; Murphy, D. M.; Katich, J. M.; Kupc, A.; Williamson, C.

    2016-12-01

    Although coarse-mode aerosol (>1 µm diameter), composed mainly of mineral dust and sea-salt, is highly abundant over large regions of the world, these particles form a particularly poorly understood and characterized subset of atmospheric aerosol constituents. The NASA-sponsored Atmospheric Tomography Mission (ATom) is an unprecedented field program that investigates how human emissions affect air quality and climate change. ATom provides a singular opportunity to characterize the global coarse-mode size distribution by continuously profiling between 0.2 and 13 km with the NASA DC-8 research aircraft while traveling from the high Arctic down south the middle of the Pacific Ocean, to the Southern Ocean and back north over the Atlantic Ocean basin in four seasons. For ATom, the DC-8 aircraft has been equipped with multiple instruments to observe the composition of the air. The coarse mode and cloud particle size distribution is measured in-situ with a Cloud, Aerosol, and Precipitation Spectrometer (CAPS) mounted under the wing of the DC-8 research aircraft. The CAPS consists of an optical spectrometer providing size distributions in the size range between 0.5 and 50 µm and an imager detecting number concentration, size and shape of particles between 15 and 930 µm diameter. Early ATom flights indicated complicated vertical layering: over the sea, we regularly observed sea salt aerosol which extended from the ground up to 0.6-1 km altitude. In addition - depending on the location of the measurements - we frequently found layers with coarse mode aerosol originating from deserts and biomass burning aerosol aloft. In this study, we will present first results of coarse mode aerosol observations from the entire first ATom deployment in summer 2016. We will show vertical profiles of coarse mode aerosol number concentration, discuss their interhemispheric differences, and look into the question how frequently coarse-mode aerosol is externally mixed with submicron black

  5. Atmospheric washout of radioactive aerosol for different types of precipitation events

    Energy Technology Data Exchange (ETDEWEB)

    Bernauer, Felix

    2015-12-15

    Ionizing radiation is widely used in many applications such as medical diagnostics and radiotherapy, where the beneficial aspect of radiation exposure is obvious. However, the exposure of human beings to ionizing radiation may also have some negative effects on human health. After the Fukushima Dai-Ichi nuclear power plant accident measured deposition patterns did not match to patterns predicted by atmospheric transport models used in decision support systems. It was suggested that one reason for these discrepancies might be that these models do not differentiate between deposition by rain and snow. Up to now much effort has been spent on the theoretical and experimental investigation of the washout of atmospheric aerosol particles by rain. In contrast, only limited knowledge is available on the washout efficiency of snow, due to the complexity of the process. Therefore, the aim of the presented work was to analyze wet deposition of aerosol particles and particle bound radionuclides in different types of precipitation events. The thesis focused on below-cloud scavenging of aerosol particles in a size range from 10 nm to 510 nm in solid phase precipitation events. It is based on measurements of natural precipitation and natural aerosol particle concentration that were performed in the free atmosphere, at the Environmental Research Station Schneefernerhaus. For this purpose, a method was developed to characterize and classify precipitation events, which goes beyond the common differentiation between liquid, mixed and solid phase precipitation. The method included use of a 2D-Video Disdrometer (2DVD), that was adapted for the detection of mixed and solid phase hydrometeors (e.g. snowflakes). A new matching algorithm, that was developed for this thesis, allowed detection of solid, mixed and liquid phase hydrometeors with a maximum dimension larger than 0.5 mm. On the basis of shape and velocity descriptors, a classification algorithm that differentiates between three

  6. The sources, properties, and evolution of organic aerosols in the atmosphere

    Science.gov (United States)

    Jimenez, J. L.

    2015-12-01

    Organic aerosols (OA) account for about 1/2 of the submicron particle mass in the atmosphere leading to important impacts on climate, human health, and other issues, but their sources, properties, and evolution are poorly understood. OA is comprised of primary OA (POA, emitted in the particle phase) and secondary OA (SOA, formed by gas-to-particle conversion). Together with others in the community and contrary to the understanding at the time, we demonstrated in the mid-2000s that SOA dominates over POA at most locations. This paradigm shift has led to intense research on the sources, processing, properties, and fate of SOA. Because pre-existing and commercial instruments were very limited for the analysis of the complex mixtures of highly oxidized species comprising real OA, we developed or co-developed several experimental and data analysis techniques aimed at extracting more information out of ambient and laboratory air, and pioneered their application in field experiments. We proposed a new paradigm (Jimenez et al., Science, 2009) that is consistent with worldwide measurements and in which OA and OA precursor gases evolve continuously by becoming increasingly oxidized, less volatile, and more hygroscopic, leading to the formation of oxygenated organic aerosol (OOA), with concentrations comparable to those of sulfate aerosol throughout the Northern Hemisphere. The amount of SOA formed from urban air is remarkably consistent across the world, although the contributions of different sources remain a subject of debate. Biomass burning emissions rarely form additional OA mass after emission, although rapid chemical aging is always observed. Global model-measurement comparisons suggest the need for a large (100 Tg/yr) "anthropogenically-controlled" SOA source, thought to be dominated by anthropogenically-enhanced biogenic SOA. SOA formed from several pathways from biogenic emissions is starting to be better characterized, as are key SOA properties such as

  7. Chemical Characterization of Secondary Organic Aerosol Formed from Atmospheric Aqueous-phase Reactions of Phenolic Compounds

    Science.gov (United States)

    Yu, L.; Smith, J.; Anastasio, C.; Zhang, Q.

    2012-12-01

    Phenolic compounds, which are released in significant amounts from biomass burning, may undergo fast aqueous-phase reactions to form secondary organic aerosol (SOA) in the atmosphere. Understanding the aqueous-phase reaction mechanisms of these compounds and the composition of their reaction products is thus important for constraining SOA sources and predicting organic aerosol properties in models. In this study, we investigate the aqueous-phase reactions of three phenols (phenol, guaiacol and syringol) with two oxidants - excited triplet states (3C*) of non-phenolic aromatic carbonyls and hydroxyl radical (OH). By employing four analytical methods including high-resolution aerosol mass spectrometry, total organic carbon analysis, ion chromatography, and liquid chromatography-mass spectrometry, we thoroughly characterize the chemical compositions of the low volatility reaction products of phenols and propose formation mechanisms based on this information. Our results indicate that phenolic SOA is highly oxygenated, with O/C ratios in the range of 0.83-1.03, and that the SOA of phenol is usually more oxidized than those of guaiacol and syringol. Among the three precursors, syringol generates the largest fraction of higher molecular weight (MW) products. For the same precursor, the SOA formed via reaction with 3C* is less oxidized than that formed via reaction with OH. In addition, oxidation by 3C* enhances the formation of higher MW species, including phenolic dimers, higher oligomers and hydroxylated products, compared to reactions initiated by OH, which appear to favor the formation of organic acids. However, our results indicate that the yields of small organic acids (e.g., formate, acetate, oxalate, and malate) are low for both reaction pathways, together accounting for less than 5% of total SOA mass.

  8. Generation and size classification of single-walled carbon nanotube aerosol using atmospheric pressure pulsed laser ablation (AP-PLA)

    Science.gov (United States)

    Klanwan, Jiraporn; Seto, Takafumi; Furukawa, Takuma; Otani, Yoshio; Charinpanitkul, Tawatchai; Kohno, Masamichi; Hirasawa, Makoto

    2010-10-01

    Gas suspended single-walled carbon nanotubes (SWCNTs) with single tube diameter smaller than 2 nm and length of longer than 500 nm were generated by simple and continuous system using laser ablation technique under atmospheric conditions. Graphite target containing 0.5 wt%-nickel and 0.5 wt%-cobalt was ablated by Nd:YAG laser in an electrical furnace under atmospheric pressure of nitrogen flow that allowed one step and continuous synthesis of the SWCNTs. Size distribution of the gas suspended SWCNTs aerosol was measured using size-classification by a differential mobility analyzer (DMA) coupled with a condensation particle counter (CPC) used as a detector. Characteristics of SWCNT aerosol generated under the different temperature were also investigated using scanning and transmission electron microscopes and Raman scattering. Mono-mobility SWCNT aerosol with mobility diameter of 100 and 200 nm was successfully prepared after the size separation using a DMA.

  9. Generation and size classification of single-walled carbon nanotube aerosol using atmospheric pressure pulsed laser ablation (AP-PLA)

    Energy Technology Data Exchange (ETDEWEB)

    Klanwan, Jiraporn; Seto, Takafumi, E-mail: seto@t.kanazawa-u.ac.jp; Furukawa, Takuma; Otani, Yoshio [Kanazawa University, Department of Chemical and Material Engineering (Japan); Charinpanitkul, Tawatchai [Chulalongkorn University, Center of Excellence in Particle Technology, Faculty of Engineering (Thailand); Kohno, Masamichi [Kyushu University, Department of Mechanical Engineering (Japan); Hirasawa, Makoto [National Institute of Advanced Industrial Science and Technology (AIST), Advanced Manufacturing Research Institute (Japan)

    2010-10-15

    Gas suspended single-walled carbon nanotubes (SWCNTs) with single tube diameter smaller than 2 nm and length of longer than 500 nm were generated by simple and continuous system using laser ablation technique under atmospheric conditions. Graphite target containing 0.5 wt%-nickel and 0.5 wt%-cobalt was ablated by Nd:YAG laser in an electrical furnace under atmospheric pressure of nitrogen flow that allowed one step and continuous synthesis of the SWCNTs. Size distribution of the gas suspended SWCNTs aerosol was measured using size-classification by a differential mobility analyzer (DMA) coupled with a condensation particle counter (CPC) used as a detector. Characteristics of SWCNT aerosol generated under the different temperature were also investigated using scanning and transmission electron microscopes and Raman scattering. Mono-mobility SWCNT aerosol with mobility diameter of 100 and 200 nm was successfully prepared after the size separation using a DMA.

  10. Urban light pollution - The effect of atmospheric aerosols on astronomical observations at night

    Science.gov (United States)

    Joseph, Joachim H.; Mekler, Yuri; Kaufman, Yoram J.

    1991-01-01

    The transfer of diffuse city light from a localized source through a dust-laden atmosphere with optical depth less than 0.5 has been analyzed in the source-observer plane on the basis of an approximate treatment. The effect on several types of astronomical observation at night has been studied, considering different size distributions and amounts as well as particle shapes of the aerosols. The analysis is made in terms of the signal-to-noise ratios for a given amount of aerosol. The model is applied to conditions at the Wise Astronomical Observatory in the Negev desert, and limiting backgrounds for spectroscopy, photometry, and photography of stars and extended objects have been calculated for a variety of signal-to-noise ratios. Applications to observations with different equipment at various distances from an urban area of any size are possible. Due to the use of signal-to-noise ratios, the conclusions are different for the different experimental techniques used in astronomy.

  11. Do aerosols act as catalysts in the OH radical initiated atmospheric oxidation of volatile organic compounds?

    Science.gov (United States)

    Sørensen, M.; Hurley, M. D.; Wallington, T. J.; Dibble, T. S.; Nielsen, O. J.

    Smog chamber/FTIR techniques were used to study the relative reactivity of OH radicals with methanol, ethanol, phenol, C 2H 4, C 2H 2, and p-xylene in 750 Torr of air diluent at 296±2 K. Experiments were performed with, and without, 500-8000 μg m -3 (4000-50 000 μm 2 cm -3 surface area per volume) of NaCl, (NH 4) 2SO 4 or NH 4NO 3 aerosol. In contrast to the recent findings of Oh and Andino (Atmospheric Environment 34 (2000) 2901, 36 (2002) 149; International Journal of Chemical Kinetics 33 (2001) 422) there was no discernable effect of aerosol on the rate of loss of the organic compounds via reaction with OH radicals. Gas kinetic theory arguments cast doubt upon the findings of Oh and Andino. The available data suggest that the answer to the title question is "No". As part of this work the rate constants for reactions of OH radicals with methanol, ethanol, and phenol in 750 Torr of air at 296 K were determined to be: kOH+CH 3OH =(8.12±0.54)×10 -13, kOH+C 2H 5OH =(3.47±0.32)×10 -12 and kOH+phenol=(3.27±0.31)×10 -11 cm 3 molecule -1 s -1.

  12. Dispersion of aerosol particles in the free atmosphere using ensemble forecasts

    Directory of Open Access Journals (Sweden)

    T. Haszpra

    2013-10-01

    Full Text Available The dispersion of aerosol particle pollutants is studied using 50 members of an ensemble forecast in the example of a hypothetical free atmospheric emission above Fukushima over a period of 2.5 days. Considerable differences are found among the dispersion predictions of the different ensemble members, as well as between the ensemble mean and the deterministic result at the end of the observation period. The variance is found to decrease with the particle size. The geographical area where a threshold concentration is exceeded in at least one ensemble member expands to a 5–10 times larger region than the area from the deterministic forecast, both for air column "concentration" and in the "deposition" field. We demonstrate that the root-mean-square distance of any particle from its own clones in the ensemble members can reach values on the order of one thousand kilometers. Even the centers of mass of the particle cloud of the ensemble members deviate considerably from that obtained by the deterministic forecast. All these indicate that an investigation of the dispersion of aerosol particles in the spirit of ensemble forecast contains useful hints for the improvement of risk assessment.

  13. The role of catchment vegetation in reducing atmospheric inputs of pollutant aerosols in Ganga river.

    Science.gov (United States)

    Shubhashish, Kumar; Pandey, Richa; Pandey, Jitendra

    2012-08-01

    The role of woody perennials in the Ganga river basin in modifying the run-off quality as influenced by atmospheric deposition of pollutant aerosols was investigated. The concentration of seven nutrients and eight metals were measured in atmospheric deposits as well as in run-off water under the influence of five woody perennials. Nutrient retention was recorded maximum for Bougainvillea spectabilis ranged from 4.30 % to 33.70 %. Metal retention was recorded highest for Ficus benghalensis ranged from 5.15 % to 36.98 %. Although some species showed nutrient enrichment, all the species considered in the study invariably contribute to reduce nutrients and metal concentration in run-off water. Reduction in run off was recorded maximum for B. spectabilis (nutrient 6.48 %-40.66 %; metal 7.86 %-22.85 %) and minimum for Ficus religiosa (nutrient 1.68 %-27.19 %; metal 6.55 %-31.55 %). The study forms the first report on the use of woody perennials in reducing input of atmospheric pollutants to Ganga river and has relevance in formulating strategies for river basin management.

  14. Atmospheric emitted radiance interferometer (AERI): Status and the aerosol explanation for extra window region emissions

    Energy Technology Data Exchange (ETDEWEB)

    Revercomb, H.E.; Knuteson, R.O.; Best, F.A.; Dirkx, T.P. [Univ. of Wisconsin, Madison, WI (United States)] [and others

    1996-04-01

    High spectral resolution observations of downwelling emission from 3 to 19 microns have been made by the Atmospheric Emitted Radiance Interferometer (AERI) Prototype at the Southern Great Plains (SGP) Cloud and Radiative Testbed (CART) site for over two years. The spectral data set from AERI provides a basis for improving clear sky radiative transfer; determining the radiative impact of clouds, including the derivation of cloud radiative properties; defining the influences of aerosols in the window regions; and retrieving boundary layer state properties, including temperature, water vapor, and other trace gases. The data stream of radiometrically and spectrally calibrated radiances is routinely provided by Pacific Northwest Laboratory (PNL) to those science teams requesting it, and further information on the instrument and data characteristics is available in the ARM Science Team proceedings for 1993 and 1994 and in several conference publications. This paper describes the AERI status, calibration, field experiment wit a new AERI-01 and schedule, window region emissions, and future AERI plans.

  15. The optical constants of several atmospheric aerosol species - Ammonium sulfate, aluminum oxide, and sodium chloride

    Science.gov (United States)

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

    1976-01-01

    An investigation is conducted of problems which are related to a use of measured optical constants in the simulation of the optical constants of real atmospheric aerosols. The techniques of measuring optical constants are discussed, taking into account transmission measurements through homogeneous and inhomogeneous materials, the immersion of a material in a liquid of a known refractive index, the consideration of the minimum deviation angle of prism measurement, the interference of multiply reflected light, reflectivity measurements, and aspects of mathematical analysis. Graphs show the real and the imaginary part of the refractive index as a function of wavelength for aluminum oxide, NaCl, and ammonium sulfate. Tables are provided for the dispersion parameters and the optical constants.

  16. Comparison of on-line and off-line methods to quantify reactive oxygen species (ROS) in atmospheric aerosols

    Science.gov (United States)

    Fuller, S. J.; Wragg, F. P. H.; Nutter, J.; Kalberer, M.

    2014-08-01

    Atmospheric aerosol particle concentrations have been linked with a wide range of pulmonary and cardio-vascular diseases but the particle properties responsible for these negative health effects are largely unknown. It is often speculated that reactive oxygen species (ROS) present in atmospheric particles lead to oxidative stress in, and ultimately disease of, the human lung. The quantification of ROS is highly challenging because some ROS components such as radicals are highly reactive and therefore short-lived. Thus, fast analysis methods are likely advantageous over methods with a long delay between aerosol sampling and ROS analysis. We present for the first time a detailed comparison of conventional off-line and fast on-line methods to quantify ROS in organic aerosols. For this comparison a new and fast on-line instrument was built and characterized to quantify ROS in aerosol particles with high sensitivity and a limit of detection of 4 nmol H2O2 equivalents per m3 air. ROS concentrations are measured with a time resolution of approximately 15 min, which allows the tracking of fast changing atmospheric conditions. The comparison of the off-line and on-line method shows that, in oxidized organic model aerosol particles, the majority of ROS have a very short lifetime of a few minutes whereas a small fraction is stable for a day or longer. This indicates that off-line techniques, where there is often a delay of hours to days between particle collection and ROS analysis, may severely underestimate true ROS concentrations and that fast on-line techniques are necessary for a reliable ROS quantification in atmospheric aerosol particles and a meaningful correlation with health outcomes.

  17. Bioactive and total endotoxins in atmospheric aerosols in the Pearl River Delta region, China

    Science.gov (United States)

    Cheng, Jessica Y. W.; Hui, Esther L. C.; Lau, Arthur P. S.

    2012-02-01

    Endotoxin, a toxic and pyrogenic substance in gram-negative bacteria in atmospheric aerosols was measured over a period of one year at Nansha, Guangzhou and Hong Kong in the Pearl River Delta region, China. Atmospheric aerosols were collected by high-volume samplers. The bioactive endotoxin levels in the samples were determined using the Limulus Amebocyte Lysate (LAL) assay after extraction with pyrogen-free water while the total endotoxin levels were measured by quantifying the biomarker, 3-hydroxy fatty acids (3-OHFAs) with GC-MS. Results showed that there was no significant difference (0.19 endotoxin level in PM 10 among sites (average concentrations ranged from 0.34 to 0.39 EU m -3). However, Hong Kong showed a significantly lower ( p endotoxin level in PM 10 (average of 17.4 ng m -3) compared with Nansha's 29.4 ng m -3 and Guangzhou's 32.7 ng m -3. The bioactive endotoxins were found to be associated with the coarse mode (PM 2.5-10) of the particulates of natural origins while the total endotoxins were associated more with the fine mode (PM 2.5) of the particulates of anthropogenic origins. When normalized with particulate mass, the endotoxin loading is much higher in summer as a result of the increased growth of the bacteria when climatic conditions are favorable. The chemically determined total endotoxins were 3-4 orders of magnitude higher than the bioactive endotoxins quantified using the LAL assay. Correlation analyses between the bioactive endotoxins and 3-OHFAs with different carbon length were analyzed. Results showed that the correlations detected vary among sites and particulate sizes. Although no generalization between the total and bioactive endotoxins can be drawn from the study, the levels reported in this study suggests that the discrepancies between the two measurement approaches, and the bioactive potential of 3-OHFAs with individual carbon chains deserve further investigation.

  18. Toward a Minimal Representation of Aerosols in Climate Models: Description and Evaluation in the Community Atmosphere Model CAM5

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaohong; Easter, Richard C.; Ghan, Steven J.; Zaveri, Rahul A.; Rasch, Philip J.; Shi, Xiangjun; Lamarque, J.-F.; Gettelman, A.; Morrison, H.; Vitt, Francis; Conley, Andrew; Park, S.; Neale, Richard; Hannay, Cecile; Ekman, A. M.; Hess, Peter; Mahowald, N.; Collins, William D.; Iacono, Michael J.; Bretherton, Christopher S.; Flanner, M. G.; Mitchell, David

    2012-05-21

    A modal aerosol module (MAM) has been developed for the Community Atmosphere Model version 5 (CAM5), the atmospheric component of the Community Earth System Model version 1 (CESM1). MAM is capable of simulating the aerosol size distribution and both internal and external mixing between aerosol components, treating numerous complicated aerosol processes and aerosol physical, chemical and optical properties in a physically based manner. Two MAM versions were developed: a more complete version with seven-lognormal modes (MAM7), and a three-lognormal mode version (MAM3) for the purpose of long-term (decades to centuries) simulations. Major approximations in MAM3 include assuming immediate mixing of primary organic matter (POM) and black carbon (BC) with other aerosol components, merging of the MAM7 fine dust and fine sea salt modes into the accumulation mode, merging of the MAM7 coarse dust and coarse sea salt modes into the single coarse mode, and neglecting the explicit treatment of ammonia and ammonium cycles. Simulated sulfate and secondary organic aerosol (SOA) mass concentrations are remarkably similar between MAM3 and MAM7 as most ({approx}90%) of these aerosol species are in the accumulation mode. Differences of POM and BC concentrations between MAM3 and MAM7 are also small (mostly within 10%) because of the assumed hygroscopic nature of POM, so that freshly emitted POM and BC are wet-removed before mixing internally with soluble aerosol species. Sensitivity tests with the POM assumed to be hydrophobic and with slower aging process increase the POM and BC concentrations, especially at high latitudes (by several times). The mineral dust global burden differs by 10% and sea salt burden by 30-40% between MAM3 and MAM7 mainly due to the different size ranges for dust and sea salt modes and different standard deviations of log-normal size distribution for sea salt modes between MAM3 and MAM7. The model is able to qualitatively capture the observed geographical and

  19. Atmospheric aerosols size distribution properties in winter and pre-monsoon over western Indian Thar Desert location

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, Chhagan, E-mail: chhaganpanwar@gmail.com; Vyas, B. M. [Department of Physics, M.L. Sukhadia University, Udaipur-313001 (India)

    2016-05-06

    The first ever experimental results over Indian Thar Desert region concerning to height integrated aerosols size distribution function in particles size ranging between 0.09 to 2 µm such as, aerosols columnar size distribution (CSD), effective radius (R{sub eff}), integrated content of total aerosols (N{sub t}), columnar content of accumulation and coarse size aerosols particles concentration (N{sub a}) (size < 0.5 µm) and (N{sub c}) (size between 0.5 to 2 µm) have been described specifically during winter (a stable weather condition and intense anthropogenic pollution activity period) and pre-monsoon (intense dust storms of natural mineral aerosols as well as unstable atmospheric weather condition period) at Jaisalmer (26.90°N, 69.90°E, 220 m above surface level (asl)) located in central Thar desert vicinity of western Indian site. The CSD and various derived other aerosols size parameters are retrieved from their average spectral characteristics of Aerosol Optical Thickness (AOT) from UV to Infrared wavelength spectrum measured from Multi-Wavelength solar Radiometer (MWR). The natures of CSD are, in general, bio-modal character, instead of uniformly distributed character and power law distributions. The observed primary peaks in CSD plots are seen around about 10{sup 13} m{sup 2} μm{sup −1} at radius range 0.09-0.20 µm during both the seasons. But, in winter months, secondary peaks of relatively lower CSD values of 10{sup 10} to 10{sup 11} m{sup 2}/μm{sup −1} occur within a lower radius size range 0.4 to 0.6 µm. In contrast to this, while in dust dominated and hot season, the dominated secondary maxima of the higher CSD of about 10{sup 12} m{sup 2}μm{sup −3} is found of bigger aerosols size particles in a rage of 0.6 to 1.0 µm which is clearly demonstrating the characteristics of higher aerosols laden of bigger size aerosols in summer months relative to their prevailed lower aerosols loading of smaller size aerosols particles (0

  20. A long-term study of aerosol modulation of atmospheric and surface solar heating over Pune, India

    Directory of Open Access Journals (Sweden)

    Sumit Kumar

    2012-12-01

    Full Text Available Implications of aerosol characteristics, observed during a five-year (2004–2009 period over Pune (a tropical urban location, to short-wave radiation budget are reported. A discrete ordinate radiative transfer (DISORT model with a code, namely, Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART, has been used to carry out the radiative transfer computations. The validity of the method is demonstrated using independent ground-based remote sensing observations. Uncertainties in the estimates are also quantified. Clear-sky forcing reveals the points that include (1 Large negative bottom-of-the-atmosphere (BOA forcing (more than−30 Wm−2 in all the months with peaks during October, December and March when the surface forcing exceeds~−40 Wm−2, and (2 Surface forcing values are higher for pre-monsoon months, while they are comparable for winter and post-monsoon months. The top-of-the-atmosphere (TOA forcing is found to be negative during all the seasons. Large differences between TOA and BOA forcing during pre-monsoon, winter and post-monsoon indicate large absorption of radiant energy (~30 Wm−2 within the atmosphere during these seasons, thus increasing atmospheric heating by~1 K/d. These values imply that aerosols have considerable impact on the atmosphere–surface system by causing substantial warming/cooling at the atmosphere/surface. This persistent trend in strong atmospheric absorption is likely to alter atmospheric thermodynamic conditions and thus affects circulation considerably.

  1. Impact of absorbing aerosols on the simulation of climate over the Indian region in an atmospheric general circulation model

    Directory of Open Access Journals (Sweden)

    A. Chakraborty

    2004-04-01

    Full Text Available The impact of anthropogenic absorbing aerosols (such as soot on the climate over the Indian region has been studied using the NCMRWF general circulation model. The absorbing aerosols increase shortwave radiative heating of the lower troposphere and reduce the heating at the surface. These effects have been incorporated as heating of the lower troposphere (up to 700hPa and cooling over the continental surface based on INDOEX measurements. The heating effect is constant in the pre-monsoon season and reduces to zero during the monsoon season. It is shown that even in the monsoon season when the aerosol forcing is zero, there is an overall increase in rainfall and a reduction in surface temperature over the Indian region. The rainfall averaged over the Tropics shows a small reduction in most of the months during the January to September period. The impact of aerosol forcing, the model's sensitivity to this forcing and its interaction with model-physics has been studied by changing the cumulus parameterization from the Simplified Arakawa-Schubert (SAS scheme to the Kuo scheme. During the pre-monsoon season the major changes in precipitation occur in the oceanic Inter Tropical Convergence Zone (ITCZ, where both the schemes show an increase in precipitation. This result is similar to that reported in Chung2002. On the other hand, during the monsoon season the changes in precipitation in the continental region are different in the SAS and Kuo schemes. It is shown that the heating due to absorbing aerosols changes the vertical moist-static stability of the atmosphere. The difference in the precipitation changes in the two cumulus schemes is on account of the different responses in the two parameterization schemes to changes in vertical stability. Key words. Atmospheric composition and structure (aerosols and particles – Meteorology and atmospheric dynamics (tropical meteorology; precipitation

  2. A Compact Mobile Ozone Lidar for Atmospheric Ozone and Aerosol Profiling

    Science.gov (United States)

    De Young, Russell; Carrion, William; Pliutau, Denis

    2014-01-01

    A compact mobile differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone air quality campaigns. This lidar is integrated into the Tropospheric Ozone Lidar Network (TOLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver with associated Licel photon counting and analog channels. The laser transmitter consist of a Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. The system has been configured to enable mobile operation from a trailer and was deployed to Denver, CO July 15-August 15, 2014 supporting the DISCOVER-AQ campaign. Ozone curtain plots and the resulting science are presented.

  3. A compact mobile ozone lidar for atmospheric ozone and aerosol profiling

    Science.gov (United States)

    De Young, Russell; Carrion, William; Pliutau, Denis

    2014-10-01

    A compact mobile differential absorption lidar (DIAL) system has been developed at NASA Langley Research Center to provide ozone, aerosol and cloud atmospheric measurements in a mobile trailer for ground-based atmospheric ozone air quality campaigns. This lidar is integrated into the Tropospheric Ozone Lidar Network (TOLNet) currently made up of four other ozone lidars across the country. The lidar system consists of a UV and green laser transmitter, a telescope and an optical signal receiver with associated Licel photon counting and analog channels. The laser transmitter consists of a Q-switched Nd:YLF inter-cavity doubled laser pumping a Ce:LiCAF tunable UV laser with all the associated power and lidar control support units on a single system rack. The system has been configured to enable mobile operation from a trailer and was deployed to Denver, CO July 15-August 15, 2014 supporting the DISCOVER-AQ campaign. Ozone curtain plots and the resulting science are presented.

  4. Surface aerosol and rehabilitation properties of ground-level atmosphere in the mountains of the North Caucasus

    Science.gov (United States)

    Reps, Valentina; Efimenko, Natalia; Povolotskaya, Nina; Abramtsova, Anna; Ischenko, Dmitriy; Senik, Irina; Slepikh, Victor

    2017-04-01

    The rehabilitative properties (RP) of ground-level atmosphere (GA) of Russian resorts are considered as natural healing resources and received state legal protection [1]. Due to global urbanization the chemical composition and particle size distribution of the surface aerosol are changing rapidly. However, the influence of surface aerosol on the RP of GA has been insufficiently studied. At the resort region of the North Caucasus complex monitoring (aerosol, trace gases NOx, CO, O3, CH4; periodically - heavy metals) is performed at two high levels (860 masl - a park zone of a large mountain resort, 2070 masl - alpine grassland, the net station). The results of the measurements are used in programs of bioclimatic, landscape and medical monitoring to specify the influence of aerosol on rehabilitation properties of the environment and human adaptative reserves. The aerosol particles of size range 500-1000 nm are used as a marker of the pathogenic effect of aerosol [2]. In the conditions of regional urbanization and complicated mountain atmospheric circulation the influence of aerosol on RP of GA and the variability of heart rhythm with the volunteers at different heights were investigated. At the height of 860 masl (urbanized resort) there have been noticed aerosol variations in the range of 0,04-0,35 particles/cm3 (slightly aerosol polluted), in mountain conditions - background pollution aerosol level. The difference of bioclimatic conditions at the specified high-rise levels has been referred to the category of contrasts. The natural aero ionization ∑(N+)+(N-) varied from 960 ion/cm3 to 1460 ion/cm3 in the resort park (860 m); from 1295 ion/cm3 to 4850 ion/cm3 on the Alpine meadow (2070 m); from 1128 ion/cm3 to 3420 ion/cm3 - on the tested site near the edge of the pinewood (1720 m). In the group of volunteers the trip from low-hill terrain zone (860 m) to the lower zone of highlands (2070 m) caused the activation of neuro and humoral regulation, vegetative and

  5. Laboratory Studies of Planetary Hazes: composition of cool exoplanet atmospheric aerosols with very high resolution mass spectrometry

    Science.gov (United States)

    Moran, Sarah E.; Horst, Sarah; He, Chao; Flandinet, Laurene; Moses, Julianne I.; Orthous-Daunay, Francois-Regis; Vuitton, Veronique; Wolters, Cedric; Lewis, Nikole

    2017-10-01

    We present first results of the composition of laboratory-produced exoplanet haze analogues. With the Planetary HAZE Research (PHAZER) Laboratory, we simulated nine exoplanet atmospheres of varying initial gas phase compositions representing increasing metallicities (100x, 1000x, and 10000x solar) and exposed them to three different temperature regimes (600, 400, and 300 K) with two different “instellation” sources (a plasma source and a UV lamp). The PHAZER exoplanet experiments simulate a temperature and atmospheric composition phase space relevant to the expected planetary yield of the Transiting Exoplanet Survey Satellite (TESS) mission as well as recently discovered potentially habitable zone exoplanets in the TRAPPIST-1, LHS-1140, and Proxima Centauri systems. Upon exposure to the energy sources, all of these experiments produced aerosol particles, which were collected in a dry nitrogen glove box and then analyzed with an LTQ Orbitrap XL™ Hybrid Ion Trap-Orbitrap Mass Spectrometer utilizing m/z ranging from 50 to 1000. The collected aerosol samples were found to contain complex organics. Constraining the composition of these aerosols allows us to better understand the photochemical and dynamical processes ongoing in exoplanet atmospheres. Moreover, these data can inform our telescope observations of exoplanets, which is of critical importance as we enter a new era of exoplanet atmosphere observation science with the upcoming launch of the James Webb Space Telescope. The molecular makeup of these haze particles provides key information for understanding exoplanet atmospheric spectra, and constraining the structure and behavior of clouds, hazes, and other aerosols is at the forefront of exoplanet atmosphere science.

  6. Characteristics of size-resolved atmospheric inorganic and carbonaceous aerosols in urban Shanghai

    Science.gov (United States)

    Ding, X. X.; Kong, L. D.; Du, C. T.; Zhanzakova, A.; Fu, H. B.; Tang, X. F.; Wang, L.; Yang, X.; Chen, J. M.; Cheng, T. T.

    2017-10-01

    Size-segregated aerosol particles were collected with a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) at an urban site in Shanghai, China for four non-consecutive months representing four seasons from 2015 to 2016. Chemical composition, including water-soluble ions as well as organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC) of size-resolved (0.056-18 μm) atmospheric aerosols in four seasons and in different polluted cases were studied. The size distributions of sulfate, nitrate and ammonium (SNA) and carbonaceous aerosol (OC, EC and SOC) were discussed and the potential sources of PM1.8-associated secondary species (SO42-, NO3-, SNA and SOC) in different seasons were identified by potential source contribution function (PSCF) model. Results showed that atmospheric ultrafine and fine particle pollution in Shanghai were very serious during the study period. Most of the water-soluble ions tended to be enriched in fine particles, especially being abundant in the droplet mode in polluted cases. Compared with sulfate, size distributions of nitrate and ammonium presented more significant seasonal variations and showed distinctive characteristics in polluted days. Abundant nitrate was concentrated in fine particles in cold seasons (spring and winter), whereas it was enriched in coarse mode during summer and autumn. The droplet mode sulfate with high concentration did not result in the aggravation of air pollution, while the nucleation mode sulfate may have made a great contribution to the air pollution in urban Shanghai. It was also found that the formation of air pollution in urban Shanghai had a significant link with nitrate and ammonium, especially with nitrate and ammonium in condensation mode and droplet mode, and the contribution of sulfate to the pollution formation in Shanghai would somehow be surpassed by the increasing nitrate and ammonium. OC and EC concentrations from spring to winter were found to be 11.10, 7.10, 12

  7. ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

    2004-04-01

    This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of September 2003 through February 2004. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. Results highlighted in this report include chemical fractionation of the organic fraction to quantify the ratio of organic mass to organic carbon (OM/OC). The average OM/OC ratio for the 31 samples analyzed so far is 1.89, ranging between 1.62 and 2.53, which is consistent with expectations for an atmospherically processed regional aerosol. Analysis of the single particle data reveals that a on a particles in Pittsburgh consist of complex mixture of primary and secondary components. Approximately 79% of all particles measured with the instrument containing some form of carbon, with Carbonaceous Ammonium Nitrate (54.43%) being the dominant particle class. PMCAMx predictions were compared with data from more than 50 sites of the STN network located throughout the Eastern United States for the July 2001 period. OC and sulfate concentrations predicted by PMCAMx are within {+-}30% of the observed concentration at most of these sites. Spherical Aluminum Silicate particle concentrations (SAS) were used to estimate the contribution of primary coal emissions to fine particle levels at the central monitoring site. Primary emissions from coal combustion contribute on average 0.44 {+-} 0.3 {micro}g/m{sup 3} to PM{sub 2.5} at the site or 1.4 {+-} 1.3% of the total PM{sub 2.5} mass. Chemical mass balance analysis was performed to apportion the primary organic aerosol. About 70% of the primary OC emissions are from vehicular sources, with the gasoline contribution being on average three times greater than the diesel emissions in the summer.

  8. Aerosol lidar observations of atmospheric mixing in Los Angeles: Climatology and implications for greenhouse gas observations

    Science.gov (United States)

    Ware, John; Kort, Eric A.; DeCola, Phil; Duren, Riley

    2016-08-01

    Atmospheric observations of greenhouse gases provide essential information on sources and sinks of these key atmospheric constituents. To quantify fluxes from atmospheric observations, representation of transport—especially vertical mixing—is a necessity and often a source of error. We report on remotely sensed profiles of vertical aerosol distribution taken over a 2 year period in Pasadena, California. Using an automated analysis system, we estimate daytime mixing layer depth, achieving high confidence in the afternoon maximum on 51% of days with profiles from a Sigma Space Mini Micropulse LiDAR (MiniMPL) and on 36% of days with a Vaisala CL51 ceilometer. We note that considering ceilometer data on a logarithmic scale, a standard method, introduces, an offset in mixing height retrievals. The mean afternoon maximum mixing height is 770 m Above Ground Level in summer and 670 m in winter, with significant day-to-day variance (within season σ = 220m≈30%). Taking advantage of the MiniMPL's portability, we demonstrate the feasibility of measuring the detailed horizontal structure of the mixing layer by automobile. We compare our observations to planetary boundary layer (PBL) heights from sonde launches, North American regional reanalysis (NARR), and a custom Weather Research and Forecasting (WRF) model developed for greenhouse gas (GHG) monitoring in Los Angeles. NARR and WRF PBL heights at Pasadena are both systematically higher than measured, NARR by 2.5 times; these biases will cause proportional errors in GHG flux estimates using modeled transport. We discuss how sustained lidar observations can be used to reduce flux inversion error by selecting suitable analysis periods, calibrating models, or characterizing bias for correction in post processing.

  9. Aerosol lidar observations of atmospheric mixing in Los Angeles: Climatology and implications for greenhouse gas observations.

    Science.gov (United States)

    Ware, John; Kort, Eric A; DeCola, Phil; Duren, Riley

    2016-08-27

    Atmospheric observations of greenhouse gases provide essential information on sources and sinks of these key atmospheric constituents. To quantify fluxes from atmospheric observations, representation of transport-especially vertical mixing-is a necessity and often a source of error. We report on remotely sensed profiles of vertical aerosol distribution taken over a 2 year period in Pasadena, California. Using an automated analysis system, we estimate daytime mixing layer depth, achieving high confidence in the afternoon maximum on 51% of days with profiles from a Sigma Space Mini Micropulse LiDAR (MiniMPL) and on 36% of days with a Vaisala CL51 ceilometer. We note that considering ceilometer data on a logarithmic scale, a standard method, introduces, an offset in mixing height retrievals. The mean afternoon maximum mixing height is 770 m Above Ground Level in summer and 670 m in winter, with significant day-to-day variance (within season σ = 220m≈30%). Taking advantage of the MiniMPL's portability, we demonstrate the feasibility of measuring the detailed horizontal structure of the mixing layer by automobile. We compare our observations to planetary boundary layer (PBL) heights from sonde launches, North American regional reanalysis (NARR), and a custom Weather Research and Forecasting (WRF) model developed for greenhouse gas (GHG) monitoring in Los Angeles. NARR and WRF PBL heights at Pasadena are both systematically higher than measured, NARR by 2.5 times; these biases will cause proportional errors in GHG flux estimates using modeled transport. We discuss how sustained lidar observations can be used to reduce flux inversion error by selecting suitable analysis periods, calibrating models, or characterizing bias for correction in post processing.

  10. Satellite-Observed Urbanization Characters in Shanghai, China: Aerosols, Urban Heat Island Effect, and Land–Atmosphere Interactions

    Directory of Open Access Journals (Sweden)

    Gary Pereira

    2011-01-01

    Full Text Available Urbanization reflects how human-activities affect natural climate system. Accurately assessing the urban system by comparing it with the nearby rural regions helps to identify the impacts of urbanization. This work uses the recent satellite observed aerosol, skin temperature, land cover, albedo, cloud fraction and water vapor measurements to reveal how the city of Shanghai, one of the biggest, dense urban areas in East Asia, affects land surface and atmosphere conditions. In addition, the National Aeronautics and Space Administration (NASA ground observations from AErosol RObotic NETwork (AERONET is also used to reveal diurnal, seasonal, and interannual variations of the heavy aerosol load over Shanghai region. Furthermore, Shanghai reduces surface albedo, total column water vapor, cloud fraction and increases land skin temperature than rural region. These observations prove that Shanghai significantly modifies local and regional land surface physical properties as well as physical processes, which lead to the urban heat island effect (UHI.

  11. Interpreting the Ultraviolet Aerosol Index Observed with the OMI Satellite Instrument to Understand Absorption by Organic Carbon Aerosols and Implications for Atmospheric Oxidation

    Science.gov (United States)

    Hammer, M. S.; Martin, R.; van Donkelaar, A.; Buchard, V.; Torres, O.; Ridley, D. A.; Spurr, R. J. D.

    2015-12-01

    Absorption of solar radiation by aerosols plays a major role in radiative forcing and atmospheric photochemistry. Many atmospheric chemistry models tend to overestimate tropospheric OH concentrations compared to observations. Accurately representing aerosol absorption in the UV could help rectify the discrepancies between simulated and observed OH concentrations. We develop a simulation of the Ultraviolet Aerosol Index (UVAI), using the 3-D chemical transport model GEOS-Chem coupled with the Vector Linearized Discrete Ordinate Radiative Transfer model (VLIDORT). The simulation is applied to interpret UVAI observations from the Ozone Monitoring Instrument (OMI). Simulated and observed values are highly consistent in regions where mineral dust dominates the UVAI, but a large negative bias (-0.4 to -1.0) exists between simulated and observed values in biomass burning regions. We implement optical properties for absorbing organic aerosol, known as brown carbon (BrC), into GEOS-Chem and evaluate the simulation with observed UVAI values over biomass burning regions. The spectral dependence of absorption after adding BrC to the model is broadly consistent with reported observations for biomass burning aerosol, with Absorbing Angstrom Exponent (AAE) values ranging from 2.7 in the UV to 1.3 across the UV-Near IR spectrum. The addition of absorbing BrC decreases the mean bias between simulated and OMI UVAI values from -0.60 to -0.08 over North Africa in January, from -0.40 to -0.003 over South Asia in April, from -1.0 to -0.24 over southern Africa in July, and from -0.50 to +0.34 over South America in September. We assess the effect of the additional UV absorption by BrC on atmospheric photochemistry by examining ozone photolysis frequencies (J(O(1D))) and tropospheric OH concentrations in GEOS-Chem. The inclusion of BrC decreases J(O(1D)) and OH by up to 35% over biomass burning regions, and reduces the global bias in OH.

  12. Daily and seasonal variation of aerosol concentration in the atmosphere near the surface in continental climate of Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Koutsenogii, P. [Inst. of Chemical Kinetics and Combustion, Novosibirsk (Russian Federation)

    1995-12-31

    Novosibirsk region is the area in southern part of West-Siberian lowland, covering about 200,000 km{sup 2}. The properties of atmospheric aerosol in Novosibirsk region were studied during few campaigns in the years 1992 and 1993, one complex expedition in Summer of 1994 and durable observations in Akademgorodok in the years 1993, 1994. Akademgorodok is situated 25 km S from the city Novosibirsk, has population of about 100,000 and no industry. Three different locations in remote areas of Novosibirsk region were used for the measurements. The first was situated 12 km E from Akademgorodok, and 30 km from Novosibirsk near the village Kljutchi. The second location was situated close to Lake Tchany in western part of Novosibirsk region. The third location was situated in south-western part of Novosibirsk region, 12 km from the town Karasuk. The total aerosol light scattering by aerosol particles was measured by commercially available nephelometer FAN-A in terms of units, related to the molecular scattering of clean air, measured by the same nephelometer. Aerosol samples in which the content of sulfate-, nitrate-, and cloride-anions was determined, using ion liquid chromatography, were collected with Whatman 41 or AFA-HA filters. Aerosol mass concentration was measured by weighting of AFA-HA filters. Aerosol particles were sampled on the filters with the volume velocity of about 500 l/min for Whatman 41 and 120 l/min for AFA-HA and mean sampling duration of 24 hours. The total aerosol number concentration was measured with a condensation nuclei counter TSI 3020

  13. Determination of total and non-water soluble iodine in atmospheric aerosols by thermal extraction and spectrometric detection (TESI).

    Science.gov (United States)

    Gilfedder, B S; Chance, R; Dettmann, U; Lai, S C; Baker, A R

    2010-09-01

    Iodine has recently been of interest in atmospheric chemistry due to its role in tropospheric ozone depletion, modification of the HO/HO(2) ratio and aerosol nucleation. Gas-phase iodine chemistry is tightly coupled to the aerosol phase through heterogeneous reactions, which are dependent on iodine concentrations and speciation in the aerosol. To date, the only method available for total iodine determination in aerosols is collection on filters by impaction and quantification by neutron activation analysis (NAA). NAA is not widely available to all working groups and is costly to commission. Here, we present a method to determine total iodine concentrations in aerosol impact filter samples by combustion of filter sub-samples (approximately 5 cm(2)) at 1,000 degrees C, trapping in deionised water and quantification by UV/Vis spectroscopy. Both quartz and cellulose filters were analysed from four separate sampling campaigns. The method proved to be sensitive (3sigma = 6 ng absolute iodine approximately 3 pmol m(-3)) precise (RSD approximately 5%) and accurate, as determined by external and standard addition calibrations. Total iodine concentrations ranged from 10 pmol m(-3) over the Southern Ocean to 100 pmol m(-3) over the tropical Atlantic, in agreement with previous estimates. The soluble iodine concentration (extracted with water and measured by ICP-MS) was then subtracted from the total iodine to yield non-water-soluble iodine (NSI). The NSI fraction ranged from 20% to 53% of total iodine, and thus can be significant in some cases.

  14. An automated analyzer to measure surface-atmosphere exchange fluxes of water soluble inorganic aerosol compounds and reactive trace gases.

    Science.gov (United States)

    Thomas, Rick M; Trebs, Ivonne; Otjes, René; Jongejan, Piet A C; Ten Brink, Harry; Phillips, Gavin; Kortner, Michael; Meixner, Franz X; Nemitz, Eiko

    2009-03-01

    Here, we present a new automated instrument for semicontinuous gradient measurements of water-soluble reactive trace gas species (NH3, HNO3, HONO, HCl, and SO2) and their related aerosol compounds (NH4+, NO3-, Cl-, SO4(2-)). Gas and aerosol samples are collected simultaneously at two heights using rotating wet-annular denuders and steam-jet aerosol collectors, respectively. Online (real-time) analysis using ion chromatography (IC) for anions and flow injection analysis (FIA) for NH4+ and NH3 provide a half-hourly averaged gas and aerosol gradients within each hour. Through the use of syringe pumps, IC preconcentration columns, and high-quality purified water, the system achieves detection limits (3sigma-definition) under field conditions of typically: 136/207,135/114, 29/ 22,119/92, and 189/159 ng m(-3) for NH3/NH4+, HNO3/NO3-, HONO/ NO2-, HCl/Cl- and SO2/SO4(2-), respectively. The instrument demonstrates very good linearity and accuracy for liquid and selected gas phase calibrations over typical ambient concentration ranges. As shown by examples from field experiments, the instrument provides sufficient precision (3-9%), even at low ambient concentrations, to resolve vertical gradients and calculate surface-atmosphere exchange fluxes undertypical meteorological conditions of the atmospheric surface layer using the aerodynamic gradient technique.

  15. Application of several activity coefficient models to water-organic-electrolyte aerosols of atmospheric interest

    Directory of Open Access Journals (Sweden)

    T. Raatikainen

    2005-01-01

    Full Text Available In this work, existing and modified activity coefficient models are examined in order to assess their capabilities to describe the properties of aqueous solution droplets relevant in the atmosphere. Five different water-organic-electrolyte activity coefficient models were first selected from the literature. Only one of these models included organics and electrolytes which are common in atmospheric aerosol particles. In the other models, organic species were solvents such as alcohols, and important atmospheric ions like NH4+ could be missing. The predictions of these models were compared to experimental activity and solubility data in aqueous single electrolyte solutions with 31 different electrolytes. Based on the deviations from experimental data and on the capabilities of the models, four predictive models were selected for fitting of new parameters for binary and ternary solutions of common atmospheric electrolytes and organics. New electrolytes (H+, NH4+, Na+, Cl-, NO3- and SO42- and organics (dicarboxylic and some hydroxy acids were added and some modifications were made to the models if it was found useful. All new and most of the existing parameters were fitted to experimental single electrolyte data as well as data for aqueous organics and aqueous organic-electrolyte solutions. Unfortunately, there are very few data available for organic activities in binary solutions and for organic and electrolyte activities in aqueous organic-electrolyte solutions. This reduces model capabilities in predicting solubilities. After the parameters were fitted, deviations from measurement data were calculated for all fitted models, and for different data types. These deviations and the calculated property values were compared with those from other non-electrolyte and organic-electrolyte models found in the literature. Finally, hygroscopic growth factors were calculated for four 100 nm organic-electrolyte particles and these predictions were compared to

  16. Determination of the concentration of aerosol particles in a vertical atmospheric column from satellite measurements of the spectral optical depth

    Science.gov (United States)

    Lysenko, S. A.; Kugeiko, M. M.

    2011-11-01

    We propose a method for fast retrieval of the inhalable particle concentration (PM2.5 and PM10) in a vertical atmospheric column from satellite measurements of the aerosol optical depth (AOD) without using a priori assumptions concerning the refractive index and the aerosol particle size distribution function. The method is based on a polynomial regression between PM2.5, PM10, and AOD at the wavelengths 466 nm and 644 nm, established from AERONET data. We have studied the sensitivity of the method to errors in the optical measurements and have estimated the errors in retrieval of PM2.5 and PM10 for different atmospheric situations. We carry out parametrization of the regressions on the value of the integrated air moisture content.

  17. Atmospheric trace elements in aerosols observed over the Southern Ocean and coastal East Antarctica

    Directory of Open Access Journals (Sweden)

    Guojie Xu

    2014-11-01

    Full Text Available Atmospheric aerosol samples were collected over the Southern Ocean (SO and coastal East Antarctica (CEA during the austral summer of 2010/11. Samples were analysed for trace elements, including Na, Mg, K, Al, Fe, Mn, Ni, Cd and Se, by inductively coupled plasma mass spectrometry (ICP-MS. The mean atmospheric concentrations over the SO were 1100 ng m−3 for Na, 190 ng m−3 for Mg, 150 ng m−3 for Al, 14 ng m−3 for Fe, 0.46 ng m−3 for Mn and 0.25 ng m−3 for Se. Over CEA, the mean concentrations were 990 ng m−3 for Na, 180 ng m−3 for Mg, 190 ng m−3 for Al, 26 ng m−3 for Fe, 0.70 ng m−3 for Mn and 0.29 ng m−3 for Se. Particle size distributions, enrichment factors (EFs and correlation analysis indicate that Na, Mg and K mainly came from the marine source, while Al, Fe and Mn were mainly from the crustal source, which also contributed to Mg and K over CEA. High EFs were associated with Ni, Cd and Se, suggesting likely contributions from mixed sources from the Antarctic continent, long-range transport, marine biogenic emissions and anthropogenic emissions. Sea-salt elements (Na, Mg, K were mainly accumulated in the coarse mode, and crustal elements (Al, Fe, Mn presented a bimodal size distribution pattern. Bioactive elements (Fe, Ni, Cd were enriched in the fine mode, especially with samples collected over the SO, possibly affecting biogeochemical cycles in this oceanic region.

  18. Evaluation of the multi-angle implementation of atmospheric correction (MAIAC) aerosol algorithm through intercomparison with VIIRS aerosol products and AERONET

    Science.gov (United States)

    Superczynski, Stephen D.; Kondragunta, Shobha; Lyapustin, Alexei I.

    2017-03-01

    The multi-angle implementation of atmospheric correction (MAIAC) algorithm is under evaluation for use in conjunction with the Geostationary Coastal and Air Pollution Events mission. Column aerosol optical thickness (AOT) data from MAIAC are compared against corresponding data from the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument over North America during 2013. Product coverage and retrieval strategy, along with regional variations in AOT through comparison of both matched and unmatched seasonally gridded data, are reviewed. MAIAC shows extended coverage over parts of the continent when compared to VIIRS, owing to its pixel selection process and ability to retrieve aerosol information over brighter surfaces. To estimate data accuracy, both products are compared with Aerosol Robotic Network level 2 measurements to determine the amount of error present and discover if there is any dependency on viewing geometry and/or surface characteristics. Results suggest that MAIAC performs well over this region with a relatively small bias of -0.01; however, there is a tendency for greater negative biases over bright surfaces and at larger scattering angles. Additional analysis over an expanded area and longer time period are likely needed to determine a comprehensive assessment of the products' capability over the Western Hemisphere.

  19. An Algorithm for the Vertical Structure of Aerosol Extinction in the Lowest Kilometer of the Atmosphere: Rev. 1

    Science.gov (United States)

    2017-11-01

    to be used. The statement of sky conditions can contain three pieces of information: the cloud ceiling height (or absence of a cloud ceiling), the...function of altitude. The statement of sky conditions can contain the following pieces of information: cloud ceiling height (or lack of a cloud ceiling...Structure ofAerosol Extinction in the Lowest Kilometerof the Atmosphere: Rev. 1 by Melvin G Heaps and Robert D Johnson US Army Electronics Research and

  20. Review and uncertainty assessment of size-resolved scavenging coefficient formulations for below-cloud snow scavenging of atmospheric aerosols

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2013-10-01

    Full Text Available Theoretical parameterizations for the size-resolved scavenging coefficient for atmospheric aerosol particles scavenged by snow (Λsnow need assumptions regarding (i snow particle–aerosol particle collection efficiency E, (ii snow-particle size distribution N(Dp, (iii snow-particle terminal velocity VD, and (iv snow-particle cross-sectional area A. Existing formulas for these parameters are reviewed in the present study, and uncertainties in Λsnow caused by various combinations of these parameters are assessed. Different formulations of E can cause uncertainties in Λsnow of more than one order of magnitude for all aerosol sizes for typical snowfall intensities. E is the largest source of uncertainty among all the input parameters, similar to rain scavenging of atmospheric aerosols (Λrain as was found in a previous study by Wang et al. (2010. However, other parameters can also cause significant uncertainties in Λsnow, and the uncertainties from these parameters are much larger than for Λrain. Specifically, different N(Dp formulations can cause one-order-of-magnitude uncertainties in Λsnow for all aerosol sizes, as is also the case for a combination of uncertainties from both VD and A. Assumptions about dominant snow-particle shape (and thus different VD and A will cause an uncertainty of up to one order of magnitude in the calculated scavenging coefficient. In comparison, uncertainties in Λrain from N(Dp are smaller than a factor of 5, and those from VD are smaller than a factor of 2. As expected, Λsnow estimated from empirical formulas generated from field measurements falls in the upper range of, or is higher than, the theoretically estimated values, which can be explained by additional processes/mechanisms that influence field-derived Λsnow but that are not considered in the theoretical Λsnow formulas. Predicted aerosol concentrations obtained by using upper range vs. lower range of Λsnow values (a difference of around two orders

  1. Aqueous-Phase Reactions of Isoprene with Sulfoxy Radical Anions as a way of Wet Aerosol Formation in the Atmosphere

    Science.gov (United States)

    Kuznietsova, I.; Rudzinski, K. J.; Szmigielski, R.; Laboratory of the Environmental Chemistry

    2011-12-01

    Atmospheric aerosols exhibit an important role in the environment. They have implications on human health and life, and - in the larger scale - on climate, the Earth's radiative balance and the cloud's formation. Organic matter makes up a significant fraction of atmospheric aerosols (~35% to ~90%) and may originate from direct emissions (primary organic aerosol, POA) or result from complex physico-chemical processes of volatile organic compounds (secondary organic aerosol, SOA). Isoprene (2-methyl-buta-1,3-diene) is one of the relevant volatile precursor of ambient SOA in the atmosphere. It is the most abundant non-methane hydrocarbon emitted to the atmosphere as a result of living vegetation. According to the recent data, the isoprene emission rate is estimated to be at the level of 500 TgC per year. While heterogeneous transformations of isoprene have been well documented, aqueous-phase reactions of this hydrocarbon with radical species that lead to the production of new class of wet SOA components such as polyols and their sulfate esters (organosulfates), are still poorly recognized. The chain reactions of isoprene with sulfoxy radical-anions (SRA) are one of the recently researched route leading to the formation of organosulfates in the aqueous phase. The letter radical species originate from the auto-oxidation of sulfur dioxide in the aqueous phase and are behind the phenomenon of atmospheric acid rain formation. This is a complicated chain reaction that is catalyzed by transition metal ions, such as manganese(II), iron(III) and propagated by sulfoxy radical anions . The presented work addresses the chemical interaction of isoprene with sulfoxy radical-anions in the water solution in the presence of nitrite ions and nitrous acid, which are important trace components of the atmosphere. We showed that nitrite ions and nitrous acid significantly altered the kinetics of the auto-oxidation of SO2 in the presence of isoprene at different solution acidity from 2 to 8

  2. Aqueous-phase aerosols on the air-water interface: Response of fatty acid Langmuir monolayers to atmospheric inorganic ions.

    Science.gov (United States)

    Li, Siyang; Du, Lin; Wei, Zhongming; Wang, Wenxing

    2017-02-15

    Atmospheric aerosol particles composed of a mixture of organic and inorganic compounds are common and constitute an important fraction of air pollutants. In this study, the activities of common atmospheric inorganic ions (Ag+, Zn2+, Fe3+, Fe2+, Ca2+ and Al3+) and fatty acid molecules (stearic acid and arachidic acid) at air-aqueous interface were investigated by Langmuir methods and infrared reflection-absorption spectroscopy (IRRAS). In the presence of different inorganic ions, surface pressure-area isotherms of the Langmuir films showed compressed or expanded characteristics. IRRAS spectra confirmed that the existence of inorganic ions in the fatty acid monolayer changes the surface properties of aqueous-phase aerosols. Formation of different coordination types of carboxylates at the air-water interface alters the dissolution and partitioning behavior, which has significant influence of Raoult effect on nucleating cloud droplets. Our work displays the relationship between structure and surface properties for aqueous-phase aerosols and implies an efficient method for further understanding of their formation mechanism and potential atmospheric implications. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Evaluation of trace elemental composition of aerosols in the atmosphere of Rawalpindi and Islamabad using radio analytical methods.

    Science.gov (United States)

    Qadir, Muhammad Abdul; Zaidi, Jamshaid Hussain; Ahmad, Shaikh Asrar; Gulzar, Asad; Yaseen, Muhammad; Atta, Sadia; Tufail, Asma

    2012-05-01

    Geological and anthropogenic contributions to air pollution were monitored by analyzing aerosol particulates present in the atmosphere of Rawalpindi and Islamabad, Pakistan, using instrumental neutron activation for trace elemental analysis. A scanning electron microscope was used to study particulate size distribution and morphology. Twenty two elements were analyzed and their likely sources were identified. It was found that 69% of the suspended particulate matter in the atmosphere of Islamabad, and 52% in Rawalpindi, were of a diameter less than 3 μm. The presence of Yb, Cs, Sc, Rb, Co, Eu, La, Ba, Zn and Hf indicates that a major portion of the trace elements in the aerosol particulates was due to the geological nature of the land, while Sc was considered to be arising from coal burning. The presence of Cr, Fe, Ce, Pb and Cd was attributed to anthropogenic activities at Rawalpindi and Islamabad. Unusually high concentrations of Mo and Nb were found in the atmosphere of Islamabad, based on soil derived aerosols. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Development of a methodology for the determination of radionuclides by Icp-SFMS; Desarrollo de una metodologia para la determinacion de radionuclidos en aerosoles por ICP-SFMS

    Energy Technology Data Exchange (ETDEWEB)

    Mendez G, C. G.; Romero G, E. T.; Hernandez M, H. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Solis R, C.; Chavez L, E. R., E-mail: griselmendez@fisica.unam.mx [UNAM, Instituto de Fisica, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico)

    2016-09-15

    A methodology was established for the determination of {sup 75}As, {sup 202}Hg, {sup 208}Pb, {sup 60}Ni, {sup 232}Th, {sup 234}U, {sup 235}U, {sup 238}U, by magnetic field inductive coupling mass spectrometry (Icp-SFMS) of various samples at the National Laboratory of Nuclear Forensic Research of the Instituto Nacional de Investigaciones Nucleares (ININ) in order to determine radionuclides in aerosol samples. The concentrations calculation of {sup 75}As, {sup 202}Hg, {sup 208}Pb and {sup 60}Ni allowed to validate the reliability of the proposed methodology when comparing the concentrations obtained with the application of the same and the concentrations of the same elements reported for the Certified Reference Material (CRM) of particulate atmospheric material of an urban area (Nist 1648-a), the comparison showed that the proposed methodology is feasible for the determination of not only radionuclides, but also for these trace elements. Detection and quantification limits of the order of microns of ng L{sup -1} were reached, corroborating with this the acceptance of the proposed methodology. Concentrations of the radionuclides of interest for CRM could be calculated. The concentrations of the radionuclides found in white samples and of the reagents used in the processing of the aerosol filters indicated that the calculations found belong to or correspond to the calculations that are reflected in the background measurement. Concentrations of {sup 232}Th, {sup 234}U, {sup 235}U and {sup 238}U in aerosols of the Cuernavaca City, Morelos (Mexico) showed higher values than those established by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), however the concentration of the radioisotopes per unit volume are within the typical values reported for the northern hemisphere; the value of isotopic ratios greater than unity point to the influence of anthropogenic activities or environmental factors such as the direction of the wind or the

  5. Emission or atmospheric processes? An attempt to attribute the source of large bias of aerosols in eastern China simulated by global climate models

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Tianyi; Liu, Xiaohong; Ma, Po Lun; Zhang, Qiang; Li, Zhanqing; Jiang, Yiquan; Zhang, Fang; Zhao, C.; Yang, Xin; Wu, Fang; Wang, Yuying

    2018-02-01

    Global climate models often underestimate aerosol loadings in China and these biases can have significant implications for anthropogenic aerosol radiative forcing and climate effects. The biases may be caused either by the emission inventory or the treatment of aerosol processes in the models, or both, but so far no consensus has been reached. In this study, a relatively new emission inventory based on energy-statistics and technology, Multi-resolution Emission Inventory for China (MEIC), is used to drive the Community Atmosphere Model version 5 (CAM5) to evaluate aerosol distribution and radiative effects against observations in China. The model results are compared with the model simulations with the widely used IPCC AR5 emission inventory. We find that the new MEIC emission improves the aerosol optical depth (AOD) simulations in eastern China and explains 22%-28% of the AOD low bias simulated with the AR5 emission. However, AOD is still low biased in eastern China. Seasonal variation of the MEIC emission leads to a better agreement with the observed seasonal variation of primary aerosols than the AR5 emission, but the concentrations are still underestimated. This implies that the atmospheric loadings of primary aerosols are closely related to the emission, which may still be underestimated over eastern China. In contrast, the seasonal variations of secondary aerosols depend more on aerosol processes (e.g., gas and aqueous phase production from precursor gases) that are associated with meteorological conditions and to a less extent on the emission. It indicates that the emissions of precursor gases for the secondary aerosols alone cannot explain the low bias in the model. Aerosol secondary production processes in CAM5 should also be revisited. The simulation using MEIC estimates the annual averaged aerosol direct radiative effects (ADREs) at the top of atmosphere (TOA), surface, and atmosphere to be -5.02, -18.47, and 13.45 W m-2 respectively over eastern China

  6. Physico-chemical characterization and mass closure of size- segregated atmospheric aerosols in Hyytiaelae, Finland

    Energy Technology Data Exchange (ETDEWEB)

    Saarikoski, S.; Maekelae, T.; Hillamo, R.; Kerminen, V.M. [Finnish Meteorological Institute, Research and Development, Helsinki (Finland); Aalto, P.P.; Kulmala, M. [Division of Atmospheric Sciences, Department of Physical Sciences, University of Helsinki (Finland)

    2005-07-01

    A size-segregated chemical composition of atmospheric aerosols was investigated in May 2004 at the SMEAR II station, southern Finland. Aerosols were collected using two 12-stage low pressure impactors (SDI) and two virtual impactors (VI). The samples were analyzed for mass, inorganic ions and organic (OC) and elemental carbon (EC). By comparing the gravimetric mass and the results from the chemical analyses, a chemical mass closure was constructed. In addition to the impactors an Electrical Low Pressure Impactor (ELPI), Differential Mobility Particle Sizer (DMPS) and Aerodynamic Particle Sizer (APS) were used to measure the mass size distribution continuously. The chemical composition of fine particles (particle diameter < 1 {mu}m) was very similar over the whole measurement campaign with 40% of mass composed of ammonium sulfate, 35% of OC and 5% of EC. In the submicron range the chemical mass closure of the collected samples was reached within a few percent on average. The chemical mass to gravimetric mass ratio was 0.98 {+-} 0.10 and 1.05 {+-} 0.13 (average {+-} S.D.) for the VI and SDI, respectively. Also, quite a good agreement was obtained between the mass size distributions measured with the ELPI and that measured with the DMPS-APS combination. When the total mass concentration of the fine particles was calculated, the mass concentration of the ELPI was found to be larger than that of the SDI and VI (ELPI/VI ratio 1.11{+-} 0.13). This may be due to the semivolatile components lost in impactors. For the SDI and DMPS-APS the concentration of the fine particles was smaller than that of the VI with the SDI/VI and DMPS-APS/VI ratios of 0.70 {+-} 0.11 and 0.92 {+-} 0.08, respectively. For the DMPS and APS the mass concentration was calculated from the number concentration by estimating the particle density. The particle density was assessed in two ways; from the chemical composition of the particles (composite density) and by comparing the mass obtained from the

  7. Interactions of mineral dust with pollution and clouds: An individual-particle TEM study of atmospheric aerosol from Saudi Arabia

    Science.gov (United States)

    Pósfai, Mihály; Axisa, Duncan; Tompa, Éva; Freney, Evelyn; Bruintjes, Roelof; Buseck, Peter R.

    2013-03-01

    Aerosol particles from desert dust interact with clouds and influence climate on regional and global scales. The Riyadh (Saudi Arabia) aerosol campaign was initiated to study the effects of dust particles on cloud droplet nucleation and cloud properties. Here we report the results of individual-particle studies of samples that were collected from an aircraft in April 2007. We used analytical transmission electron microscopy, including energy-dispersive X-ray spectrometry, electron diffraction, and imaging techniques for the morphological, chemical, and structural characterization of the particles. Dust storms and regional background conditions were encountered during four days of sampling. Under dusty conditions, the coarse (supermicrometer) fraction resembles freshly crushed rock. The particles are almost exclusively mineral dust grains and include common rock-forming minerals, among which clay minerals, particularly smectites, are most abundant. Unaltered calcite grains also occur, indicating no significant atmospheric processing. The particles have no visible coatings but some contain traces of sulfur. The fine (submicrometer) fraction is dominated by particles of anthropogenic origin, primarily ammonium sulfate (with variable organic coating and some with soot inclusions) and combustion-derived particles (mostly soot). In addition, submicrometer, iron-bearing clay particles also occur, many of which are internally mixed with ammonium sulfate, soot, or both. We studied the relationships between the properties of the aerosol and the droplet microphysics of cumulus clouds that formed above the aerosol layer. Under dusty conditions, when a large concentration of coarse-fraction mineral particles was in the aerosol, cloud drop concentrations were lower and droplet diameters larger than under regional background conditions, when the aerosol was dominated by submicrometer sulfate particles.

  8. Towards a quasi-complete reconstruction of past atmospheric aerosol load and composition (organic and inorganic over Europe since 1920 inferred from Alpine ice cores

    Directory of Open Access Journals (Sweden)

    S. Preunkert

    2013-07-01

    Full Text Available Seasonally resolved chemical ice core records available from the Col du Dôme glacier (4250 m elevation, French Alps, are here used to reconstruct past aerosol load and composition of the free European troposphere from before World War II to present. Available ice core records include inorganic (Na+, Ca2+, NH4+, Cl−, NO3−, and SO42− and organic (carboxylates, HCHO, humic-like substances, dissolved organic carbon, water-insoluble organic carbon, and black carbon compounds and fractions that permit reconstructing the key aerosol components and their changes over the past. It is shown that the atmospheric load of submicron aerosol has been increased by a factor of 3 from the 1921–1951 to 1971–1988 years, mainly as a result of a large increase of sulfate (a factor of 5, ammonium and water-soluble organic aerosol (a factor of 3. Thus, not only growing anthropogenic emissions of sulfur dioxide and ammonia have caused the enhancement of the atmospheric aerosol load but also biogenic emissions producing water-soluble organic aerosol. This unexpected change of biospheric source of organic aerosol after 1950 needs to be considered and further investigated in scenarios dealing with climate forcing by atmospheric aerosol.

  9. Development of an aerosol-chemistry transport model coupled to non-hydrostatic icosahedral atmospheric model (NICAM) through applying a stretched grid system to regional simulations around Japan

    Science.gov (United States)

    Goto, D.; Nakajima, T.; Masaki, S.

    2014-12-01

    Air pollution has a great impact on both climate change and human health. One effective way to tackle with these issues is a use of atmospheric aerosol-chemistry models with high-resolution in a global scale. For this purpose, we have developed an aerosol-chemistry model based on a global cloud-resolving model (GCRM), Nonhydrostatic Icosahedral Atmospheric Model (NICAM; Tomita and Satoh, Fluid. Dyn. Res. 2004; Satoh et al., J. Comput. Phys. 2008, PEPS, 2014) under MEXT/RECCA/SALSA project. In the present study, we have simulated aerosols and tropospheric ozone over Japan by our aerosol-chemistry model "NICAM-Chem" with a stretched-grid system of approximately 10 km resolution, for saving the computer resources. The aerosol and chemistry modules are based on Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS; Takemura et al., J. Geophys. Res., 2005) and Chemical AGCM for Study of Atmospheric Environment and Radiative Forcing (CHASER; Sudo et al., J. Geophys. Res., 2002). We found that our model can generally reproduce both aerosols and ozone, in terms of temporal variations (daily variations of aerosols and diurnal variations of ozone). Under MEXT/RECCA/SALSA project, we also have used these results obtained by NICAM-Chem for the assessment of their impact on human health.

  10. Evaluation of trace elemental composition of aerosols in the atmosphere of Rawalpindi and Islamabad using radio analytical methods

    Energy Technology Data Exchange (ETDEWEB)

    Qadir, Muhammad Abdul, E-mail: mabdulqadir@gmail.com [Institute of Chemistry, University of the Punjab, Lahore-54590 (Pakistan); Zaidi, Jamshaid Hussain [Pakistan Institute of Nuclear Science and Technology, Nilore, Islamabad Capital Territory (Pakistan); Ahmad, Shaikh Asrar; Gulzar, Asad [Division of Science and Technology, University of Education, Township, Lahore (Pakistan); Yaseen, Muhammad [Department of Chemistry, Gugrat University, Gugrat (Pakistan); Atta, Sadia; Tufail, Asma [Institute of Chemistry, University of the Punjab, Lahore-54590 (Pakistan)

    2012-05-15

    Geological and anthropogenic contributions to air pollution were monitored by analyzing aerosol particulates present in the atmosphere of Rawalpindi and Islamabad, Pakistan, using instrumental neutron activation for trace elemental analysis. A scanning electron microscope was used to study particulate size distribution and morphology. Twenty two elements were analyzed and their likely sources were identified. It was found that 69% of the suspended particulate matter in the atmosphere of Islamabad, and 52% in Rawalpindi, were of a diameter less than 3 {mu}m. The presence of Yb, Cs, Sc, Rb, Co, Eu, La, Ba, Zn and Hf indicates that a major portion of the trace elements in the aerosol particulates was due to the geological nature of the land, while Sc was considered to be arising from coal burning. The presence of Cr, Fe, Ce, Pb and Cd was attributed to anthropogenic activities at Rawalpindi and Islamabad. Unusually high concentrations of Mo and Nb were found in the atmosphere of Islamabad, based on soil derived aerosols. - Highlights: Black-Right-Pointing-Pointer Discussion is made on Total suspended Particulate (TSP) matter in the atmosphere. Black-Right-Pointing-Pointer Measurement of Radio active elements in the TSP by using SSNTD which was found non significant. Black-Right-Pointing-Pointer 23 Trace element analysis of the TSPs in the atmosphere of twin cities i.e. Rawalpindi and Islamabad and their relation to their sources by using Neutron activation analysis. Black-Right-Pointing-Pointer The mountain of Islamabad has some unique and important deposits of Nb and Gd , this paper will help the Geological survey of Pakistan to explore their deposits. Black-Right-Pointing-Pointer There is high level of TSPs>10 um, which is a great threat to the peoples of Islamabad.

  11. Hygroscopic properties of submicrometer atmospheric aerosol particles measured with H-TDMA instruments in various environments-a review

    Science.gov (United States)

    Swietlicki, E.; Hansson, H.-C.; Hämeri, K.; Svenningsson, B.; Massling, A.; McFiggans, G.; McMurry, P. H.; Petäjä, T.; Tunved, P.; Gysel, M.; Topping, D.; Weingartner, E.; Baltensperger, U.; Rissler, J.; Wiedensohler, A.; Kulmala, M.

    2008-07-01

    The hygroscopic properties play a vital role for the direct and indirect effects of aerosols on climate, as well as the health effects of particulate matter (PM) by modifying the deposition pattern of inhaled particles in the humid human respiratory tract. Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA) instruments have been used in field campaigns in various environments globally over the last 25 yr to determine the water uptake on submicrometre particles at subsaturated conditions. These investigations have yielded valuable and comprehensive information regarding the particle hygroscopic properties of the atmospheric aerosol, including state of mixing. These properties determine the equilibrium particle size at ambient relative humidities and have successfully been used to calculate the activation of particles at water vapour supersaturation. This paper summarizes the existing published H-TDMA results on the size-resolved submicrometre aerosol particle hygroscopic properties obtained from ground-based measurements at multiple marine, rural, urban and free tropospheric measurement sites. The data is classified into groups of hygroscopic growth indicating the external mixture, and providing clues to the sources and processes controlling the aerosol. An evaluation is given on how different chemical and physical properties affect the hygroscopic growth.

  12. Quantification of environmentally persistent free radicals and reactive oxygen species in atmospheric aerosol particles

    Science.gov (United States)

    Arangio, Andrea M.; Tong, Haijie; Socorro, Joanna; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-10-01

    Fine particulate matter plays a central role in the adverse health effects of air pollution. Inhalation and deposition of aerosol particles in the respiratory tract can lead to the release of reactive oxygen species (ROS), which may cause oxidative stress. In this study, we have detected and quantified a wide range of particle-associated radicals using electron paramagnetic resonance (EPR) spectroscopy. Ambient particle samples were collected using a cascade impactor at a semi-urban site in central Europe, Mainz, Germany, in May-June 2015. Concentrations of environmentally persistent free radicals (EPFR), most likely semiquinone radicals, were found to be in the range of (1-7) × 1011 spins µg-1 for particles in the accumulation mode, whereas coarse particles with a diameter larger than 1 µm did not contain substantial amounts of EPFR. Using a spin trapping technique followed by deconvolution of EPR spectra, we have also characterized and quantified ROS, including OH, superoxide (O2-) and carbon- and oxygen-centered organic radicals, which were formed upon extraction of the particle samples in water. Total ROS amounts of (0.1-3) × 1011 spins µg-1 were released by submicron particle samples and the relative contributions of OH, O2-, C-centered and O-centered organic radicals were ˜ 11-31, ˜ 2-8, ˜ 41-72 and ˜ 0-25 %, respectively, depending on particle sizes. OH was the dominant species for coarse particles. Based on comparisons of the EPR spectra of ambient particulate matter with those of mixtures of organic hydroperoxides, quinones and iron ions followed by chemical analysis using liquid chromatography mass spectrometry (LC-MS), we suggest that the particle-associated ROS were formed by decomposition of organic hydroperoxides interacting with transition metal ions and quinones contained in atmospheric humic-like substances (HULIS).

  13. Thermal degradation of organics for pyrolysis in space: Titan's atmospheric aerosol case study

    Science.gov (United States)

    He, Jing; Buch, Arnaud; Carrasco, Nathalie; Szopa, Cyril

    2015-03-01

    Pyrolysis coupled with mass spectry is among the instrumentation the most implemented in planetary exploration probes to analyze the chemical composition of extraterrestrial solid samples. It is used to analyze the volatile species which can be thermally extracted from the samples, including the organic fraction which is of primary interest for astrobiological purposes. However the thermal degradation of these organic materials, which can be very complex in nature or very different from organics commonly present on Earth, is badly known. This leads to a restriction in the optimization of space instrumentation, and in the interpretation of the measurements. In the present work we propose a complete overview of the thermal degradation processes studied on a model of complex organic material produced in an extraterrestrial environment, i.e. laboratory analogues of Titan's atmospheric aerosols. The thermal evolution of the studied analogues is monitored by following their mass loss, the emitted heating flux, and the evolution of their chemical composition through infrared spectroscopy and elemental analysis. The gaseous products released from the material are also analyzed by mass spectrometry, allowing to better constrain the mechanisms of chemical evolution of the samples. The complex organic material analyzed is found not to be fully decomposed when heated up to about 800 °C, with the evidence that nitrogen is still deeply incorporated in the remaining graphitic carbon nitride residue. The most appropriate pyrolysis temperature to chemically probe the studied material is found to be about 450 °C because at this temperature are detected the largest gaseous molecules which should be the most representative ones of the material pyrolyzed.

  14. Occurrence of aerosol-bound fullerenes in the Mediterranean Sea atmosphere.

    Science.gov (United States)

    Sanchís, Josep; Berrojalbiz, Naiara; Caballero, Gemma; Dachs, Jordi; Farré, Marinella; Barceló, Damià

    2012-02-07

    This work describes the assessment of a selection of fullerenes including C(60) and C(70) fullerene, N-methylfulleropyrrolidine, C(60) pyrrolidine tris-acid ethyl ester, [6,6]-Phenyl-C(61) butyric acid butyl ester and [6,6]-Thienyl C(61) butyric acid methyl ester, in airborne particulate from the Mediterranean Sea collected during two sampling campaigns from Barcelona to Istanbul and Alexandria, respectively. The analysis of the samples was carried out using a new method based on liquid chromatography coupled to mass spectrometry (LC-MS) presenting sensitivities between 5.4 and 20.9 pg/m(3). A total number of 43 samples covering the different basins of Mediterranean Sea were analyzed. Fullerenes were detected in all analyzed samples and quantifiable concentrations were found in 28 of the analyzed samples. The median of C(60) and C(70) fullerenes aerosol phase concentrations were 0.06 ng/m(3) and 0.48 ng/m(3) respectively for the Mediterranean Sea atmosphere. C(70) fullerene was the most frequently detected compound and also it was found in the higher concentrations for most samples, reaching 233.8 ng/m(3). The modeled back-trajectories disclose that those samples with higher concentrations of fullerenes were related to air masses which had been circulating over regions with an intense industrial activity, but the variability of the C(70)/C(60) ratio suggests multiple different sources. These results are related to the incidental emissions from urban and industrial development, underpinning the need of studying the possible risks associated to carbon nanoparticles in the environment and the need of evaluating the possible consequences of their ubiquitous occurrence.

  15. The composition and variability of atmospheric aerosol over Southeast Asia during 2008

    Science.gov (United States)

    Trivitayanurak, W.; Palmer, P. I.; Barkley, M. P.; Robinson, N. H.; Coe, H.; Oram, D. E.

    2012-01-01

    We use a nested version of the GEOS-Chem global 3-D chemistry transport model to better understand the composition and variation of aerosol over Borneo and the broader Southeast Asian region in conjunction with aircraft and satellite observations. Our focus on Southeast Asia reflects the importance of this region as a source of reactive organic gases and aerosols from natural forests, biomass burning, and food and fuel crops. We particularly focus on July 2008 when the UK BAe-146 research aircraft was deployed over northern Malaysian Borneo as part of the ACES/OP3 measurement campaign. During July 2008 we find using the model that Borneo (defined as Borneo Island and the surrounding Indonesian islands) was a net exporter of primary organic aerosol (42 kT) and black carbon aerosol (11 kT). We find only 13% of volatile organic compound oxidation products partition to secondary organic aerosol (SOA), with Borneo being a net exporter of SOA (15 kT). SOA represents approximately 19% of the total organic aerosol over the region. Sulphate is mainly from aqueous-phase oxidation (68%), with smaller contributions from gas-phase oxidation (15%) and advection into the regions (14%). We find that there is a large source of sea salt, as expected, but this largely deposits within the region; we find that dust aerosol plays only a relatively small role in the aerosol burden. In contrast to coincident surface measurements over Northern Borneo that find a pristine environment with evidence for substantial biogenic SOA formation we find that the free troposphere is influenced by biomass burning aerosol transported from the northwest of the Island and further afield. We find several transport events during July 2008 over Borneo associated with elevated aerosol concentrations, none of which coincide with the aircraft flights. We use MODIS aerosol optical depths (AOD) data and the model to put the July campaign into a longer temporal perspective. We find that Borneo is where the model

  16. The composition and variability of atmospheric aerosol over Southeast Asia during 2008

    Directory of Open Access Journals (Sweden)

    W. Trivitayanurak

    2012-01-01

    Full Text Available We use a nested version of the GEOS-Chem global 3-D chemistry transport model to better understand the composition and variation of aerosol over Borneo and the broader Southeast Asian region in conjunction with aircraft and satellite observations. Our focus on Southeast Asia reflects the importance of this region as a source of reactive organic gases and aerosols from natural forests, biomass burning, and food and fuel crops. We particularly focus on July 2008 when the UK BAe-146 research aircraft was deployed over northern Malaysian Borneo as part of the ACES/OP3 measurement campaign. During July 2008 we find using the model that Borneo (defined as Borneo Island and the surrounding Indonesian islands was a net exporter of primary organic aerosol (42 kT and black carbon aerosol (11 kT. We find only 13% of volatile organic compound oxidation products partition to secondary organic aerosol (SOA, with Borneo being a net exporter of SOA (15 kT. SOA represents approximately 19% of the total organic aerosol over the region. Sulphate is mainly from aqueous-phase oxidation (68%, with smaller contributions from gas-phase oxidation (15% and advection into the regions (14%. We find that there is a large source of sea salt, as expected, but this largely deposits within the region; we find that dust aerosol plays only a relatively small role in the aerosol burden. In contrast to coincident surface measurements over Northern Borneo that find a pristine environment with evidence for substantial biogenic SOA formation we find that the free troposphere is influenced by biomass burning aerosol transported from the northwest of the Island and further afield. We find several transport events during July 2008 over Borneo associated with elevated aerosol concentrations, none of which coincide with the aircraft flights. We use MODIS aerosol optical depths (AOD data and the model to put the July campaign into a longer temporal perspective. We find that Borneo is where

  17. Determination of the atmospheric optical depth due to the El Chichon stratospheric aerosol cloud in the polluted atmosphere of Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, Ignacio [Centro Universitario de Investigaciones en Ciencia del Ambiente, Universidad de Colima, Colima, Colima, (Mexico); Kondratyev, Kirill Ya. [Academician, Counsellor Center for Ecological Safety, Russian Academy of Sciences, St. Petersburg (Russian Federation); Zenteno, Gerardo [Instituto de Geofisica, UNAM, Mexico, D.F. (Mexico)

    1996-01-01

    Direct solar radiation measurements were used to determine the aerosol optical depth (AOD) increase associated with the presence of aerosol and large particles (ash) originating from the 28 March to 4 April 1982 El Chichon eruptions (17.5 degrees N, 93.3 degrees W; Mexico) on Mexico City's polluted atmospheric aerosol layer. The results are compared with those obtained at Vancouver, British Columbia, revealing that a first AOD increase occurred in both locations during May, June, and July 1982, the Mexico City AOD decay is more extended, not reaching normal climatological values until February 1983. Meanwhile, Vancouver's AOD reached minimum values in September 1982, which subsequently increased over a period from October 1982 to September 1983. This secondary maximum was recorded in Mexico City from March to August 1983. Results suggest that the first AOD increases in May, June and July 1982, both at Vancouver and Mexico City, are due chiefly to short life-time volcanic ash particles being located near the surface. However, the second AOD increases, associated with anomalously colored twilights, corresponds to stratospheric volcanic aerosols. [Spanish] Se utilizaron mediciones de radiacion solar directa para determinar el incremento de la profundidad optica del aerosol (AOD) asociada a la presencia de aerosoles y particulas grandes (cenizas) organizadas por las erupciones de El Chichon (17.5 grados N, 93.3 grados W; Mexico) del 28 de marzo al 4 de abril de 1982 sobre la capa atmosferica contaminada de la Ciudad de Mexico. Los resultados se comparan con los obtenidos en Vancouver, Colombia Britanica, relevando que un primer aumento de AOD ocurrio en ambos lugares durante mayo, junio y julio de 1982. Sin embargo, la AOD decayo en Ciudad de Mexico mas lentamente, alcanzando los valores climatologicos normales hasta febrero de 1983. Mientras tanto la AOD para Vancouver alcanzo valores minimos en septiembre de 1982; estos subsecuentemente se incrementaron en

  18. Coupling non-linear optical spectroscopy and surface chemistry: Towards new insights in atmospheric chemistry and aerosols

    Science.gov (United States)

    Abdelmonem, Ahmed; Lützenkirchen, Johannes

    2017-04-01

    For decades, the observation of atmospheric processes in general and ice nucleation in particular bridged the scales from macroscopic to microscopic levels. They delivered a wide variety of results in cloud microphysics, particularly concerning the ice nucleation ability of atmospheric aerosol particles [1]. The surface properties of an ice-nucleating particle (INP) play a major role in its ice nucleation ability. This role is not well explored in terms of water/INP-surface molecular-level interactions. For example, we found recently that surface-charge induced templating hampers ice nucleation [2]. Aging of an INP in a cloud may change its surface properties and hence its ice nucleation efficiency. To improve our understanding of heterogeneous ice nucleation, we combine chemical and optical surface techniques to probe the change in surface properties of an INP and the corresponding water structuring on it, respectively. The presentation will show the different scenarios after aging of an INP in a cloud and the impact on its ice nucleation ability. References 1. Hoose, C. and O. Mohler, Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments. Atmospheric Chemistry and Physics, 2012. 12(20): p. 9817-9854. 2. Abdelmonem, A., et al., Surface charge-induced orientation of interfacial water suppresses heterogeneous ice nucleation on α-alumina (0001). Angewandte Chemie (Submitted), 2017.

  19. Plasma-based techniques applied to the determination of metals and metalloids in atmospheric aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Smichowski, Patricia, E-mail: smichows@cnea.gov.ar [Comision Nacional de Energia Atomica, Gerencia Quimica, Pcia de Buenos Aires (Argentina)

    2011-07-01

    Full text: This lecture presents an overview of the research carried out by our group during the last decade on the determination of metals, metalloids, ions and species in atmospheric aerosols and related matrices using plasma-based techniques. In our first studies we explored the application of a size fractionation procedure and the subsequent determination of minor, major and trace elements in samples of deposited particles collected one day after the eruption of the Copahue Volcano, located in the Chile-Argentina border to assess the content of relevant elements with respect of the environment and the local population health. We employed a multi-technique approach (ICP-MS, XRD and NAA) to gain complete information of the characteristics of the sample. In addition to the study of ashes emitted for natural sources we also studied ashes of anthropogenic origin such as those arising from coal combustion in thermal power plants. For estimating the behavior and fate of elements in atmospheric particles and ashes we applied in this case a chemical fractionation procedure in order to establish the distribution of many elements amongst soluble, bound to carbonates, bound to oxides and bound to organic matter and environmental immobile fraction. Studies on the air quality of the mega-city of Buenos Aires were scarce and fragmentary and our objective was, and still is, to contribute to clarify key issues related to levels of crustal, toxic and potentially toxic elements in this air basin. Our findings were compared with average concentrations of metals and metalloids with results reported for other Latin American cities such as Sao Paulo, Mexico and Santiago de Chile. In this context, a series of studies were carried out since 2004 considering different sampling strategies to reflect local aspects of air pollution sources. In the last years, our interest was focused on the levels of traffic-related elements in the urban atmosphere. We have contributed with the first data

  20. Fluorescence from atmospheric aerosol detected by a lidar indicates biogenic particles in the lowermost stratosphere

    Directory of Open Access Journals (Sweden)

    F. Immler

    2005-01-01

    Full Text Available With a lidar system that was installed in Lindenberg/Germany, we observed in June 2003 an extended aerosol layer at 13km altitude in the lowermost stratosphere. This layer created an inelastic backscatter signal that we detected with a water vapour Raman channel, but that was not produced by Raman scattering. Also, we find evidence for inelastic scattering from a smoke plume from a forest fire that we observed in the troposphere. We interpret the unexpected properties of these aerosols as fluorescence induced by the laser beam at organic components of the aerosol particles. Fluorescence from ambient aerosol had not yet been considered detectable by lidar systems. However, organic compounds such as polycyclic aromatic hydrocarbons sticking to the aerosol particles, or bioaerosol such as bacteria, spores or pollen fluoresce when excited with UV-radiation in a way that is detectable by our lidar system. Therefore, we conclude that fluorescence from organic material released by biomass burning creates, inelastic backscatter signals that we measured with our instrument and thus demonstrate a new and powerful way to characterize aerosols by a remote sensing technique. The stratospheric aerosol layer that we have observed in Lindenberg for three consecutive days is likely to be a remnant from Siberian forest fire plumes lifted across the tropopause and transported around the globe.

  1. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    Science.gov (United States)

    Strada, Susanna; Unger, Nadine

    2016-04-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning) are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and phenology. On a global scale, our results show that global land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ˜ 9 %. At a regional scale, GPP and isoprene emission show a robust but opposite sensitivity to pollution aerosols in regions where forested canopies dominate. In eastern North America and Eurasia, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +5-8 % on an annual average. In the northwestern Amazon Basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the northwestern Amazon Basin during the dry-fire season (+5-8 %). The prevailing mechanism varies across regions: light scattering dominates in eastern North America, while a reduction in direct radiation dominates in Europe and China. Aerosol-induced GPP productivity increases in the Amazon and central Africa include an additional positive feedback from reduced canopy temperatures in response to increases in canopy conductance. In Eurasia and northeastern China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on an annual average. Future research needs to incorporate the indirect effects of aerosols and possible feedbacks from dynamic carbon allocation and phenology.

  2. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    Directory of Open Access Journals (Sweden)

    S. Strada

    2016-04-01

    Full Text Available A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and phenology. On a global scale, our results show that global land carbon fluxes (GPP and isoprene emission are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse by  ∼ 9 %. At a regional scale, GPP and isoprene emission show a robust but opposite sensitivity to pollution aerosols in regions where forested canopies dominate. In eastern North America and Eurasia, anthropogenic pollution aerosols (mainly from non-biomass burning sources enhance GPP by +5–8 % on an annual average. In the northwestern Amazon Basin and central Africa, biomass burning aerosols increase GPP by +2–5 % on an annual average, with a peak in the northwestern Amazon Basin during the dry-fire season (+5–8 %. The prevailing mechanism varies across regions: light scattering dominates in eastern North America, while a reduction in direct radiation dominates in Europe and China. Aerosol-induced GPP productivity increases in the Amazon and central Africa include an additional positive feedback from reduced canopy temperatures in response to increases in canopy conductance. In Eurasia and northeastern China, anthropogenic pollution aerosols drive a decrease in isoprene emission of −2 to −12 % on an annual average. Future research needs to incorporate the indirect effects of aerosols and possible feedbacks from dynamic carbon allocation and phenology.

  3. Lidar-measurement of the atmospheric aerosols' extinction based on the field study SAMUM-1; Lidar-Messung der Extinktion des atmosphaerischen Aerosols am Beispiel der Feldstudie SAMUM-1

    Energy Technology Data Exchange (ETDEWEB)

    Esselborn, Michael

    2008-07-01

    In the frame of this thesis a high-resolution spectral LIDAR (HSRL) was used for the field study SAMUM during May/June 2006 and January/February 2008 on board of the research aircraft Falcon. The intensity of the LIDAR signals are mainly influences by backscattering and extinction of atmospheric particles (aerosols). Using a narrow-band optical filter the HSRL allows the measurement of the molecular backscattering besides the total atmospheric backscattering. During SAMUM-1 the optical properties of the Sahara dust aerosols were measured for the first time, esp. its extinction, the ratio extinction/backscattering and the depolarization close to the source region. The results of the optical density of the aerosols were compared with satellite-based data. South of the Atlas-mountains optical aerosol densities in the range of 0.50 to 0.60 were measured.

  4. Determination of water vapor and aerosol densities in the tropospheric atmosphere from nitrogen and water vapor raman signals

    CERN Document Server

    Kim, D H; Lee, J M; Yeon, K H; Choi, S C

    1998-01-01

    A Raman lidar system has been developed for the measurement of the water-vapor mixing ratio and the aerosol backscatter and extinction coefficients. To suppress the elastic scattering from the XeCl excimer laser, an acetone edge filter and narrow-band interference filters are used. By using independently calculated backscatter and extinction coefficients, we calculate the lidar ratios (extinction coefficient divided by the backscatter coefficient). The obtained ratios between 30 and 50 sr explain the special characteristics of the aerosol existing in the atmosphere. These ratios are also used as important parameters in the lidar inversion program. We have also obtained the water-vapor mixing ratio and find that big differences exist between the ratios inside the boundary layer and those of other regions.

  5. A review on the importance of metals and metalloids in atmospheric dust and aerosol from mining operations.

    Science.gov (United States)

    Csavina, Janae; Field, Jason; Taylor, Mark P; Gao, Song; Landázuri, Andrea; Betterton, Eric A; Sáez, A Eduardo

    2012-09-01

    Contaminants can be transported rapidly and over relatively long distances by atmospheric dust and aerosol relative to other media such as water, soil and biota; yet few studies have explicitly evaluated the environmental implications of this pathway, making it a fundamental but understudied transport mechanism. Although there are numerous natural and anthropogenic activities that can increase dust and aerosol emissions and contaminant levels in the environment, mining operations are notable with respect to the quantity of particulates generated, the global extent of area impacted, and the toxicity of contaminants associated with the emissions. Here we review (i) the environmental fate and transport of metals and metalloids in dust and aerosol from mining operations, (ii) current methodologies used to assess contaminant concentrations and particulate emissions, and (iii) the potential health and environmental risks associated with airborne contaminants from mining operations. The review evaluates future research priorities based on the available literature and suggest that there is a particular need to measure and understand the generation, fate and transport of airborne particulates from mining operations, specifically the finer particle fraction. More generally, our findings suggest that mining operations play an important but underappreciated role in the generation of contaminated atmospheric dust and aerosol and the transport of metal and metalloid contaminants, and highlight the need for further research in this area. The role of mining activities in the fate and transport of environmental contaminants may become increasingly important in the coming decades, as climate change and land use are projected to intensify, both of which can substantially increase the potential for dust emissions and transport. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Atmospheric aerosol load morphological classification and retrieved visibility based on lidar backscatter measurements

    CSIR Research Space (South Africa)

    Tesfaye, M

    2010-01-01

    Full Text Available In this paper, the tropospheric aerosol load morphological classification and its impact on temporal variation of visibility are investigated using a continuous 23-hour single channel CSIR-NLC mobile LIDAR backscatter measurement. The trajectory...

  7. Aerosol Observability and Data Assimilation Investigations in Support of Atmospheric Composition Forecasts

    Science.gov (United States)

    2013-09-30

    elevated Aqua MODIS aerosol optical depth retrievals over the mid-latitude Southern Oceans through intercomparison with co-located CALIOP, MAN, and...AERONET datasets, J. Geophys. Res, in press Eck, T. F., B. N. Holben, J. S. Reid, et al., (2013), A seasonal trend of single scattering albedo in...Hsu, N. C., (2013), Critical evaluation of the MODIS Deep Blue aerosol optical depth product for data assimilation over North Africa, Atmos. Meas

  8. Design of a new multi-phase experimental simulation chamber for atmospheric photosmog, aerosol and cloud chemistry research

    Directory of Open Access Journals (Sweden)

    J. Wang

    2011-11-01

    Full Text Available A new simulation chamber has been built at the Interuniversitary Laboratory of Atmospheric Systems (LISA. The CESAM chamber (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber is designed to allow research in multiphase atmospheric (photo- chemistry which involves both gas phase and condensed phase processes including aerosol and cloud chemistry. CESAM has the potential to carry out variable temperature and pressure experiments under a very realistic artificial solar irradiation. It consists of a 4.2 m3 stainless steel vessel equipped with three high pressure xenon arc lamps which provides a controlled and steady environment. Initial characterization results, all carried out at 290–297 K under dry conditions, concerning lighting homogeneity, mixing efficiency, ozone lifetime, radical sources, NOy wall reactivity, particle loss rates, background PM, aerosol formation and cloud generation are given. Photolysis frequencies of NO2 and O3 related to chamber radiation system were found equal to (4.2 × 10−3 s−1 for JNO2 and (1.4 × 10−5 s−1 for JO1D which is comparable to the solar radiation in the boundary layer. An auxiliary mechanism describing NOy wall reactions has been developed. Its inclusion in the Master Chemical Mechanism allowed us to adequately model the results of experiments on the photo-oxidation of propene-NOx-Air mixtures. Aerosol yields for the α-pinene + O3 system chosen as a reference were determined and found in good agreement with previous studies. Particle lifetime in the chamber ranges from 10 h to 4 days depending on particle size distribution which indicates that the chamber can provide high quality data on aerosol aging processes and their effects. Being evacuable, it is possible to generate in this new chamber

  9. Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols

    Directory of Open Access Journals (Sweden)

    N. Hodas

    2016-10-01

    Full Text Available Discontinuities in apparent hygroscopicity below and above water saturation have been observed for organic and mixed organic–inorganic aerosol particles in both laboratory studies and in the ambient atmosphere. However, uncertainty remains regarding the factors that contribute to observations of low hygroscopic growth below water saturation but enhanced cloud condensation nuclei (CCN activity for a given aerosol population. Utilizing laboratory surrogates for oligomers in atmospheric aerosols, we explore the extent to which such discontinuities are influenced by organic component molecular mass and viscosity, non-ideal thermodynamic interactions between aerosol components, and the combination of these factors. Measurements of hygroscopic growth under subsaturated conditions and the CCN activity of aerosols comprised of polyethylene glycol (PEG with average molecular masses ranging from 200 to 10 000 g mol−1 and mixtures of PEG with ammonium sulfate (AS were conducted. Experimental results are compared to calculations of hygroscopic growth at thermodynamic equilibrium conducted with the Aerosol Inorganic Organic Mixtures Functional groups Activity Coefficients (AIOMFAC model, and the potential influence of kinetic limitations on observed water uptake was further explored through estimations of water diffusivity in the PEG oligomers. Particle-phase behavior, including the prevalence of liquid–liquid phase separation (LLPS, was also modeled with AIOMFAC. Under subsaturated relative humidity (RH conditions, we observed little variability in hygroscopic growth across PEG systems with different molecular masses; however, an increase in CCN activity with increasing PEG molecular mass was observed. This effect is most pronounced for PEG–AS mixtures, and, in fact, an enhancement in CCN activity was observed for the PEG10000–AS mixture as compared to pure AS, as evidenced by a 15 % reduction in critical activation diameter at a

  10. The direct effect of aerosols on the radiation budget and climate of the Earth-atmosphere system: its variability in space and time

    Science.gov (United States)

    Hatzianastassiou, N.

    2009-04-01

    Atmospheric aerosols, these tiny particles suspended in the air, play a very important role for the Earth-atmosphere climate system on both global and regional scales through various mechanisms and physical processes. The climatic effects of aerosols are determined by modifications they induce on the various components of the Earth's radiation budget. Despite the progress that has been made lately, there is still much to learn about the climatic role of aerosols in various aspects. One of the most important issues that has to be addressed is the spatial and temporal variability, especially the temporal variability of aerosol properties and their consequent radiative effects. For example, there is uncertainty with regard to aerosol radiative properties and whether or not aerosol loads are increasing or decreasing with time, and what the consequences are. Moreover, the extent to which aerosols cool or warm the planet is not clear, as well as the contribution to this cooling/warming by aerosols of natural and anthropogenic origin. Given that the aerosol radiative effects, especially on radiation reaching the Earth's surface and in the atmosphere, cannot be directly measured/observed, models are necessary to overcome this problem. Specifically, radiative transfer models (RTMs) are able to calculate the radiation fluxes within the entire Earth-atmosphere system from regional to planetary scale, and the flux changes caused by aerosols. Yet, what is more interesting for models is that they allow us to study in detail the space and time resolved aerosol radiative effects and their sensitivity to various physical parameters. Using RTMs the aerosol direct effect on solar radiation can be determined at the top of the atmosphere (DRETOA) in the atmosphere (DREatm) and at the Earth's surface (DREsurf). Using a detailed radiative transfer model together with climatological input data for surface and atmospheric variables, the direct radiative effects of aerosols (DREs) were

  11. The Role of Atmospheric Aerosol Concentration on Deep Convective Precipitation: Cloud-Resolving Model Simulations

    Science.gov (United States)

    Tao, Wei-Kuo; Li, Xiaowen; Khain, Alexander; Matsui, Toshihisa; Lang, Stephen; Simpson, Joanne

    2010-01-01

    Aerosols and especially their effect on clouds are one of the key components of the climate system and the hydrological cycle [Ramanathan et al., 2001]. Yet, the aerosol effect on clouds remains largely unknown and the processes involved not well understood. A recent report published by the National Academy of Science states "The greatest uncertainty about the aerosol climate forcing - indeed, the largest of all the uncertainties about global climate forcing - is probably the indirect effect of aerosols on clouds NRC [2001]." The aerosol effect on Clouds is often categorized into the traditional "first indirect (i.e., Twomey)" effect on the cloud droplet sizes for a constant liquid water path and the "semi-direct" effect on cloud coverage. The aerosol effect on precipitation processes, also known as the second type of aerosol indirect effect, is even more complex, especially for mixed-phase convective clouds. In this paper, a cloud-resolving model (CRM) with detailed spectral-bin microphysics was used to examine the effect of aerosols on three different deep convective cloud systems that developed in different geographic locations: South Florida, Oklahoma and the Central Pacific, In all three cases, rain reaches the ground earlier for the low CCN (clean) case. Rain suppression is also evident in all three cases with high CCN (dirty) case. However, this suppression only occurs during the first hour of the simulations. During the mature stages of the simulations, the effects of increasing aerosol concentration range from rain suppression in the Oklahoma case, to almost no effect in the Florida case, to rain enhancement in the Pacific case. These results show the complexity of aerosol interactions with convection. The model results suggest that evaporative cooling is a key process in determining whether high CCN reduces or enhances precipitation. Stronger evaporative cooling can produce a stronger cold pool and thus stronger low-level convergence through interactions

  12. Evaluation of the impact of atmospheric ozone and aerosols on the horizontal global/diffuse UV Index at Livorno (Italy)

    Science.gov (United States)

    Scaglione, Daniele; Giulietti, Danilo; Morelli, Marco

    2016-08-01

    A study was conducted at Livorno (Italy) to evaluate the impact of atmospheric aerosols and ozone on the solar UV radiation and its diffuse component at ground in clear sky conditions. Solar UV radiation has been quantified in terms of UV Index (UVI), following the ISO 17166:1999/CIE S007/E-1998 international standard. UVI has been calculated by exploiting the libRadtran radiative transfer modelling software as a function of both the Aerosols Optical Depth (AOD) and the Total Ozone Column (TOC). In particular AOD and TOC values have been remotely sensed by the Ozone Monitoring Instrument (OMI) on board the NASA's EOS (Earth Observing System) satellites constellation. An experimental confirmation was also obtained by exploiting global UVI ground-based measurements from the 26/9/14 to 12/8/15 and diffuse UVI ground-based measurements from the 17/5/15 to 12/8/15. For every considered value of Solar Zenith Angle (SZA) and atmospheric condition, estimates and measurements confirm that the diffuse component contributes for more than 50% on the global UV radiation. Therefore an exposure of human skin also to diffuse solar UV radiation can be potentially harmful for health and need to be accurately monitored, e.g. by exploiting innovative applications such as a mobile app with a satellite-based UV dosimeter that has been developed. Global and diffuse UVI variations due to the atmosphere are primarily caused by the TOC variations (typically cyclic): the maximum TOC variation detected by OMI in the area under study leads to a corresponding variation in global and diffuse UVI of about 50%. Aerosols in the area concerned, mainly of maritime nature, have instead weaker effects causing a maximum variation of the global and diffuse UVI respectively of 9% and 35% with an SZA of 20° and respectively of 13% and 10% with an SZA of 60°.

  13. Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions

    Science.gov (United States)

    Elbert, W.; Taylor, P. E.; Andreae, M. O.; Pöschl, U.

    2007-09-01

    Biogenic aerosols play important roles in atmospheric chemistry physics, the biosphere, climate, and public health. Here, we show that fungi which actively discharge their spores with liquids into the air, in particular actively wet spore discharging Ascomycota (AAM) and actively wet spore discharging Basidiomycota (ABM), are a major source of primary biogenic aerosol particles and components. We present the first estimates for the global average emission rates of fungal spores. Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001) indicate that the spores of AAM and ABM may account for a large proportion of coarse particulate matter in tropical rainforest regions during the wet season (0.7-2.3 μg m-3). For the particle diameter range of 1-10 μm, the estimated proportions are ~25% during day-time, ~45% at night, and ~35% on average. For the sugar alcohol mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively wet discharged basidiospores (ABS). ABM emissions seem to account for most of the atmospheric abundance of mannitol (10-68 ng m-3), and can explain the observed diurnal cycle (higher abundance at night). ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter (7-49 ng m-3), but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night). AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season (17-43 ng m-3), and they can also explain the observed diurnal cycle (higher abundance at night). The results of our investigations and budget calculations for tropical rainforest aerosols are consistent with measurements performed at other locations. Based on the average abundance of mannitol reported for extratropical continental boundary layer air

  14. Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions

    Directory of Open Access Journals (Sweden)

    W. Elbert

    2007-09-01

    Full Text Available Biogenic aerosols play important roles in atmospheric chemistry physics, the biosphere, climate, and public health. Here, we show that fungi which actively discharge their spores with liquids into the air, in particular actively wet spore discharging Ascomycota (AAM and actively wet spore discharging Basidiomycota (ABM, are a major source of primary biogenic aerosol particles and components. We present the first estimates for the global average emission rates of fungal spores.

    Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001 indicate that the spores of AAM and ABM may account for a large proportion of coarse particulate matter in tropical rainforest regions during the wet season (0.7–2.3 μg m−3. For the particle diameter range of 1–10 μm, the estimated proportions are ~25% during day-time, ~45% at night, and ~35% on average. For the sugar alcohol mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively wet discharged basidiospores (ABS. ABM emissions seem to account for most of the atmospheric abundance of mannitol (10–68 ng m−3, and can explain the observed diurnal cycle (higher abundance at night. ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter (7–49 ng m−3, but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night. AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season (17–43 ng m−3, and they can also explain the observed diurnal cycle (higher abundance at night. The results of our investigations and budget calculations for tropical rainforest aerosols are consistent with measurements performed at other locations.

    Based on

  15. Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO2

    Directory of Open Access Journals (Sweden)

    Z. Yu

    2017-08-01

    Full Text Available The photocatalytic ability of airborne mineral dust particles is known to heterogeneously promote SO2 oxidation, but prediction of this phenomenon is not fully taken into account by current models. In this study, the Atmospheric Mineral Aerosol Reaction (AMAR model was developed to capture the influence of air-suspended mineral dust particles on sulfate formation in various environments. In the model, SO2 oxidation proceeds in three phases including the gas phase, the inorganic-salted aqueous phase (non-dust phase, and the dust phase. Dust chemistry is described as the absorption–desorption kinetics of SO2 and NOx (partitioning between the gas phase and the multilayer coated dust. The reaction of absorbed SO2 on dust particles occurs via two major paths: autoxidation of SO2 in open air and photocatalytic mechanisms under UV light. The kinetic mechanism of autoxidation was first leveraged using controlled indoor chamber data in the presence of Arizona Test Dust (ATD particles without UV light, and then extended to photochemistry. With UV light, SO2 photooxidation was promoted by surface oxidants (OH radicals that are generated via the photocatalysis of semiconducting metal oxides (electron–hole theory of ATD particles. This photocatalytic rate constant was derived from the integration of the combinational product of the dust absorbance spectrum and wave-dependent actinic flux for the full range of wavelengths of the light source. The predicted concentrations of sulfate and nitrate using the AMAR model agreed well with outdoor chamber data that were produced under natural sunlight. For seven consecutive hours of photooxidation of SO2 in an outdoor chamber, dust chemistry at the low NOx level was attributed to 55 % of total sulfate (56 ppb SO2, 290 µg m−3 ATD, and NOx less than 5 ppb. At high NOx ( >  50 ppb of NOx with low hydrocarbons, sulfate formation was also greatly promoted by dust chemistry, but it was suppressed by

  16. Modeling atmospheric mineral aerosol chemistry to predict heterogeneous photooxidation of SO2

    Science.gov (United States)

    Yu, Zechen; Jang, Myoseon; Park, Jiyeon

    2017-08-01

    The photocatalytic ability of airborne mineral dust particles is known to heterogeneously promote SO2 oxidation, but prediction of this phenomenon is not fully taken into account by current models. In this study, the Atmospheric Mineral Aerosol Reaction (AMAR) model was developed to capture the influence of air-suspended mineral dust particles on sulfate formation in various environments. In the model, SO2 oxidation proceeds in three phases including the gas phase, the inorganic-salted aqueous phase (non-dust phase), and the dust phase. Dust chemistry is described as the absorption-desorption kinetics of SO2 and NOx (partitioning between the gas phase and the multilayer coated dust). The reaction of absorbed SO2 on dust particles occurs via two major paths: autoxidation of SO2 in open air and photocatalytic mechanisms under UV light. The kinetic mechanism of autoxidation was first leveraged using controlled indoor chamber data in the presence of Arizona Test Dust (ATD) particles without UV light, and then extended to photochemistry. With UV light, SO2 photooxidation was promoted by surface oxidants (OH radicals) that are generated via the photocatalysis of semiconducting metal oxides (electron-hole theory) of ATD particles. This photocatalytic rate constant was derived from the integration of the combinational product of the dust absorbance spectrum and wave-dependent actinic flux for the full range of wavelengths of the light source. The predicted concentrations of sulfate and nitrate using the AMAR model agreed well with outdoor chamber data that were produced under natural sunlight. For seven consecutive hours of photooxidation of SO2 in an outdoor chamber, dust chemistry at the low NOx level was attributed to 55 % of total sulfate (56 ppb SO2, 290 µg m-3 ATD, and NOx less than 5 ppb). At high NOx ( > 50 ppb of NOx with low hydrocarbons), sulfate formation was also greatly promoted by dust chemistry, but it was suppressed by the competition between NO2 and SO2

  17. Interpreting the Ultraviolet Aerosol Index Observed with the OMI Satellite Instrument to Understand Absorption by Organic Aerosols: Implications for Atmospheric Oxidation and Direct Radiative Effects

    Science.gov (United States)

    Hammer, Melanie S.; Martin, Randall V.; Donkelaar, Aaron van; Buchard, Virginie; Torres, Omar; Ridley, David A.; Spurr, Robert J. D.

    2016-01-01

    Satellite observations of the ultraviolet aerosol index (UVAI) are sensitive to absorption of solar radiation by aerosols; this absorption affects photolysis frequencies and radiative forcing. We develop a global simulation of the UVAI using the 3-D chemical transport model GEOSChem coupled with the Vector Linearized Discrete Ordinate Radiative Transfer model (VLIDORT). The simulation is applied to interpret UVAI observations from the Ozone Monitoring Instrument (OMI) for the year 2007. Simulated and observed values are highly consistent in regions where mineral dust dominates the UVAI, but a large negative bias (-0.32 to -0.97) exists between simulated and observed values in biomass burning regions. We determine effective optical properties for absorbing organic aerosol, known as brown carbon (BrC), and implement them into GEOS-Chem to better represent observed UVAI values over biomass burning regions. The inclusion of absorbing BrC decreases the mean bias between simulated and OMI UVAI values from -0.57 to -0.09 over West Africa in January, from -0.32 to +0.0002 over South Asia in April, from -0.97 to -0.22 over southern Africa in July, and from -0.50 to +0.33 over South America in September. The spectral dependence of absorption after including BrC in the model is broadly consistent with reported observations for biomass burning aerosol, with absorbing Angstrom exponent (AAE) values ranging from 2.9 in the ultraviolet (UV) to 1.3 across the UV-Near IR spectrum. We assess the effect of the additional UV absorption by BrC on atmospheric photochemistry by examining tropospheric hydroxyl radical (OH) concentrations in GEOS-Chem. The inclusion of BrC decreases OH by up to 30% over South America in September, up to 20% over southern Africa in July, and up to 15% over other biomass burning regions. Global annual mean OH concentrations in GEOS-Chem decrease due to the presence of absorbing BrC, increasing the methyl chloroform lifetime from 5.62 to 5.68 years, thus

  18. Interpreting the ultraviolet aerosol index observed with the OMI satellite instrument to understand absorption by organic aerosols: implications for atmospheric oxidation and direct radiative effects

    Directory of Open Access Journals (Sweden)

    M. S. Hammer

    2016-03-01

    Full Text Available Satellite observations of the ultraviolet aerosol index (UVAI are sensitive to absorption of solar radiation by aerosols; this absorption affects photolysis frequencies and radiative forcing. We develop a global simulation of the UVAI using the 3-D chemical transport model GEOS-Chem coupled with the Vector Linearized Discrete Ordinate Radiative Transfer model (VLIDORT. The simulation is applied to interpret UVAI observations from the Ozone Monitoring Instrument (OMI for the year 2007. Simulated and observed values are highly consistent in regions where mineral dust dominates the UVAI, but a large negative bias (−0.32 to −0.97 exists between simulated and observed values in biomass burning regions. We determine effective optical properties for absorbing organic aerosol, known as brown carbon (BrC, and implement them into GEOS-Chem to better represent observed UVAI values over biomass burning regions. The inclusion of absorbing BrC decreases the mean bias between simulated and OMI UVAI values from −0.57 to −0.09 over West Africa in January, from −0.32 to +0.0002 over South Asia in April, from −0.97 to −0.22 over southern Africa in July, and from −0.50 to +0.33 over South America in September. The spectral dependence of absorption after including BrC in the model is broadly consistent with reported observations for biomass burning aerosol, with absorbing Ångström exponent (AAE values ranging from 2.9 in the ultraviolet (UV to 1.3 across the UV–Near IR spectrum. We assess the effect of the additional UV absorption by BrC on atmospheric photochemistry by examining tropospheric hydroxyl radical (OH concentrations in GEOS-Chem. The inclusion of BrC decreases OH by up to 30 % over South America in September, up to 20 % over southern Africa in July, and up to 15 % over other biomass burning regions. Global annual mean OH concentrations in GEOS-Chem decrease due to the presence of absorbing BrC, increasing the methyl chloroform

  19. Interpreting the ultraviolet aerosol index observed with the OMI satellite instrument to understand absorption by organic aerosols: implications for atmospheric oxidation and direct radiative effects

    Science.gov (United States)

    Hammer, Melanie S.; Martin, Randall V.; van Donkelaar, Aaron; Buchard, Virginie; Torres, Omar; Ridley, David A.; Spurr, Robert J. D.

    2016-03-01

    Satellite observations of the ultraviolet aerosol index (UVAI) are sensitive to absorption of solar radiation by aerosols; this absorption affects photolysis frequencies and radiative forcing. We develop a global simulation of the UVAI using the 3-D chemical transport model GEOS-Chem coupled with the Vector Linearized Discrete Ordinate Radiative Transfer model (VLIDORT). The simulation is applied to interpret UVAI observations from the Ozone Monitoring Instrument (OMI) for the year 2007. Simulated and observed values are highly consistent in regions where mineral dust dominates the UVAI, but a large negative bias (-0.32 to -0.97) exists between simulated and observed values in biomass burning regions. We determine effective optical properties for absorbing organic aerosol, known as brown carbon (BrC), and implement them into GEOS-Chem to better represent observed UVAI values over biomass burning regions. The inclusion of absorbing BrC decreases the mean bias between simulated and OMI UVAI values from -0.57 to -0.09 over West Africa in January, from -0.32 to +0.0002 over South Asia in April, from -0.97 to -0.22 over southern Africa in July, and from -0.50 to +0.33 over South America in September. The spectral dependence of absorption after including BrC in the model is broadly consistent with reported observations for biomass burning aerosol, with absorbing Ångström exponent (AAE) values ranging from 2.9 in the ultraviolet (UV) to 1.3 across the UV-Near IR spectrum. We assess the effect of the additional UV absorption by BrC on atmospheric photochemistry by examining tropospheric hydroxyl radical (OH) concentrations in GEOS-Chem. The inclusion of BrC decreases OH by up to 30 % over South America in September, up to 20 % over southern Africa in July, and up to 15 % over other biomass burning regions. Global annual mean OH concentrations in GEOS-Chem decrease due to the presence of absorbing BrC, increasing the methyl chloroform lifetime from 5.62 to 5.68 years

  20. Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation.

    Science.gov (United States)

    Percival, Carl J; Welz, Oliver; Eskola, Arkke J; Savee, John D; Osborn, David L; Topping, David O; Lowe, Douglas; Utembe, Steven R; Bacak, Asan; McFiggans, Gordon; Cooke, Michael C; Xiao, Ping; Archibald, Alexander T; Jenkin, Michael E; Derwent, Richard G; Riipinen, Ilona; Mok, Daniel W K; Lee, Edmond P F; Dyke, John M; Taatjes, Craig A; Shallcross, Dudley E

    2013-01-01

    Carbonyl oxides ("Criegee intermediates"), formed in the ozonolysis of alkenes, are key species in tropospheric oxidation of organic molecules and their decomposition provides a non-photolytic source of OH in the atmosphere (Johnson and Marston, Chem. Soc. Rev., 2008, 37, 699, Harrison et al, Sci, Total Environ., 2006, 360, 5, Gäb et al., Nature, 1985, 316, 535, ref. 1-3). Recently it was shown that small Criegee intermediates, C.I.'s, react far more rapidly with SO2 than typically represented in tropospheric models, (Welz, Science, 2012, 335, 204, ref. 4) which suggested that carbonyl oxides could have a substantial influence on the atmospheric oxidation of SO2. Oxidation of 502 is the main atmospheric source of sulphuric acid (H2SO4), which is a critical contributor to aerosol formation, although questions remain about the fundamental nucleation mechanism (Sipilä et al., Science, 2010, 327, 1243, Metzger et al., Proc. Natl. Acad. Sci. U. S. A., 2010 107, 6646, Kirkby et al., Nature, 2011, 476, 429, ref. 5-7). Non-absorbing atmospheric aerosols, by scattering incoming solar radiation and acting as cloud condensation nuclei, have a cooling effect on climate (Intergovernmental Panel on Climate Change (IPCC), Climate Change 2007: The Physical Science Basis, Cambridge University Press, 2007, ref. 8). Here we explore the effect of the Criegees on atmospheric chemistry, and demonstrate that ozonolysis of alkenes via the reaction of Criegee intermediates potentially has a large impact on atmospheric sulphuric acid concentrations and consequently the first steps in aerosol production. Reactions of Criegee intermediates with SO2 will compete with and in places dominate over the reaction of OH with SO2 (the only other known gas-phase source of H2SO4) in many areas of the Earth's surface. In the case that the products of Criegee intermediate reactions predominantly result in H2SO4 formation, modelled particle nucleation rates can be substantially increased by the improved

  1. The new sample preparation line for radiocarbon measurements on atmospheric aerosol at LABEC

    Energy Technology Data Exchange (ETDEWEB)

    Calzolai, G., E-mail: calzolai@fi.infn.i [Department of Physics and Astronomy, Universita degli Studi di Firenze, Florence (Italy); INFN - Istituto Nazionale di Fisica Nucleare, Florence (Italy); Bernardoni, V. [Department of Physics, Universita degli Studi di Milano and INFN, Milan (Italy); Chiari, M.; Fedi, M.E. [INFN - Istituto Nazionale di Fisica Nucleare, Florence (Italy); Lucarelli, F. [Department of Physics and Astronomy, Universita degli Studi di Firenze, Florence (Italy); INFN - Istituto Nazionale di Fisica Nucleare, Florence (Italy); Nava, S. [INFN -Istituto Nazionale di Fisica Nucleare, Florence (Italy); Riccobono, F. [Department of Physics, Universita degli Studi di Milano and INFN, Milan (Italy); Taccetti, F. [INFN - Istituto Nazionale di Fisica Nucleare, Florence (Italy); Valli, G.; Vecchi, R. [Department of Physics, Universita degli Studi di Milano and INFN, Milan (Italy)

    2011-02-01

    Research highlights: {yields} A new sample preparation line for {sup 14}C analysis on aerosol samples was set up at LABEC. {yields} Effective combustion, selection and collection of the CO{sub 2} were achieved. {yields} The efficiency of the line is consistent with 100%. {yields} AMS tests of samples: reproducibility better than 3 per mille ; good background and accuracy.The line is designed to allow future {sup 14}C measurements on OC/EC. -- Abstract: Radiocarbon measurements on the carbonaceous aerosol fractions have been demonstrated as an effective tool for aerosol source apportionment. For these measurements, a new sample preparation facility was installed at the INFN-LABEC laboratory of Florence (Italy). The line was designed to allow the preparation of samples from different carbonaceous fractions: the combustion of the aerosol samples can be performed in helium or oxygen flows, according to thermal sequences. The evolved CO{sub 2} is cryogenically trapped and reduced to graphite, which is the target material for following Accelerator Mass Spectrometry (AMS) {sup 14}C measurements. This preparation line is described in detail in the paper. As a first step, the line was tested by means of AMS measurements performed on standards to check the reproducibility and the accuracy of the system; moreover, preliminary measurements on the total carbon fraction in aerosol samples were made. Results of these measurements are also reported.

  2. Origin of atmospheric aerosols at the Pierre Auger Observatory using studies of air mass trajectories in South America

    Science.gov (United States)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bardenet, R.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Foerster, N.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giammarchi, M.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kadija, K.; Kambeitz, O.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Pontz, M.; Porcelli, A.; Preda, T.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Thao, N. T.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Curci, G.

    2014-11-01

    The Pierre Auger Observatory is making significant contributions towards understanding the nature and origin of ultra-high energy cosmic rays. One of its main challenges is the monitoring of the atmosphere, both in terms of its state variables and its optical properties. The aim of this work is to analyse aerosol optical depth τa(z) values measured from 2004 to 2012 at the observatory, which is located in a remote and relatively unstudied area of Pampa Amarilla, Argentina. The aerosol optical depth is in average quite low - annual mean τa(3.5 km) ∼ 0.04 - and shows a seasonal trend with a winter minimum - τa(3.5 km) ∼ 0.03 -, and a summer maximum - τa(3.5 km) ∼ 0.06 -, and an unexpected increase from August to September - τa(3.5 km) ∼ 0.055. We computed backward trajectories for the years 2005 to 2012 to interpret the air mass origin. Winter nights with low aerosol concentrations show air masses originating from the Pacific Ocean. Average concentrations are affected by continental sources (wind-blown dust and urban pollution), whilst the peak observed in September and October could be linked to biomass burning in the northern part of Argentina or air pollution coming from surrounding urban areas.

  3. Instrument development and characterization of atmospheric aerosol physical properties through airborne measurement

    Science.gov (United States)

    Wang, Jian

    To increase the speed of submicron aerosol size distribution measurements, a mixing condensation nucleus counter (MCNC) has been developed. By carefully designing the mixing chamber and condenser, the response time of the MCNC was significantly reduced. Our experiments demonstrate that a differential mobility analyzer (DMA) coupled with the developed MCNC can measure complete aerosol size distributions in as little as 2 seconds. The effects of bends and elbows on the diffusional losses of particle in nanometer range were studied. The results show that the effect of bends and elbows on particle diffusion loss is significant, and for Reynolds number smaller than 250, the enhancement of diffusion losses due to bends and elbows is sensitive to both the relative orientations of the bends and elbows and the lengths of straight tubing between them. When the Reynolds number exceeds 250, the enhancement is insensitive to the actual flow configurations. Experimental results are presented, which can be used for design of aerosol flow systems at Reynolds number larger than 250. To minimize the airborne sampling bias, an advanced differential mobility analyzer (DMA) system for measuring submicron aerosol size distribution at ambient relative humidity, with special attention to implementation on aircraft, has been developed. The system includes an active RH controller, a cylindrical differential mobility analyzer (CDMA), and a condensation nucleus counter. A cascade controller maintains the RH inside the CDMA at ambient RH by actively adding or removing water vapor from the air stream. The flows are controlled with feedback PID controllers, which compensate for the variation of pressure as the aircraft changes altitude. During the ACE-Asia experiment, the above DMA system, together with an aerodynamic particle sizer (APS), was used to characterize aerosol size distributions in East Asia on board of CIRPAS Twin Otter aircraft. Besides providing the aerosol size characteristics

  4. Measuring and modeling the hygroscopic growth of two humic substances in mixed aerosol particles of atmospheric relevance

    Directory of Open Access Journals (Sweden)

    I. R. Zamora

    2013-09-01

    Full Text Available The hygroscopic growth of atmospheric particles affects atmospheric chemistry and Earth's climate. Water-soluble organic carbon (WSOC constitutes a significant fraction of the dry submicron mass of atmospheric aerosols, thus affecting their water uptake properties. Although the WSOC fraction is comprised of many compounds, a set of model substances can be used to describe its behavior. For this study, mixtures of Nordic aquatic fulvic acid reference (NAFA and Fluka humic acid (HA, with various combinations of inorganic salts (sodium chloride and ammonium sulfate and other representative organic compounds (levoglucosan and succinic acid, were studied. We measured the equilibrium water vapor pressure over bulk solutions of these mixtures as a function of temperature and solute concentration. New water activity (aw parameterizations and hygroscopic growth curves at 25 °C were calculated from these data for particles of equivalent composition. We examined the effect of temperature on the water activity and found a maximum variation of 9% in the 0–30 °C range, and 2% in the 20–30 °C range. Five two-component mixtures were studied to understand the effect of adding a humic substance (HS, such as NAFA and HA, to an inorganic salt or a saccharide. The deliquescence point at 25 °C for HS-inorganic mixtures did not change significantly from that of the pure inorganic species. However, the hygroscopic growth of HA / inorganic mixtures was lower than that exhibited by the pure salt, in proportion to the added mass of HA. The addition of NAFA to a highly soluble solute (ammonium sulfate, sodium chloride or levoglucosan in water had the same effect as the addition of HA to the inorganic species for most of the water activity range studied. Yet, the water uptake of these NAFA mixtures transitioned to match the growth of the pure salt or saccharide at high aw values. The remaining four mixtures were based on chemical composition data for different

  5. Vertical Structure and Optical Properties of Titans Aerosols from Radiance Measurements Made Inside and Outside the Atmosphere

    Science.gov (United States)

    Doose, Lyn R.; Karkoschka, Erich; Tomasko, Martin G.; Anderson, Carrie M.

    2017-01-01

    Prompted by the detection of stratospheric cloud layers by Cassini's Composite Infrared Spectrometer (CIRS; see Anderson, C.M., Samuelson, R.E. [2011]. Icarus 212, 762-778), we have re-examined the observations made by the Descent Imager/Spectral Radiometer (DISR) in the atmosphere of Titan together with two constraints from measurements made outside the atmosphere. No evidence of thin layers (albedo measured from outside the atmosphere the decrease in the single scattering albedo of Titan's aerosols at high altitudes, noted in earlier studies of DISR data, must continue to much higher altitudes. The altitude of Titan's limb as a function of wavelength requires that the scale height of the aerosols decrease with altitude from the 65 km value seen in the DISR observations below 140 km to the 45 km value at higher altitudes. We compared the variation of radiance with nadir angle observed in the DISR images to improve our aerosol model. Our new aerosol model fits the altitude and wavelength variations of the observations at small and intermediate nadir angles but not for large nadir angles, indicating an effect that is not reproduced by our radiative transfer model. The volume extinction profiles are modeled by continuous functions except near the enhancement level near 55 km altitude. The wavelength dependence of the extinction optical depth is similar to earlier results at wavelengths from 500 to 700 nm, but is smaller at shorter wavelengths and larger toward longer wavelengths. A Hapke-like model is used for the ground reflectivity, and the variation of the Hapke single scattering albedo with wavelength is given. Fits to the visible spectrometers looking upward and downward are achieved except in the methane bands longward of 720 nm. This is possibly due to uncertainties in extrapolation of laboratory measurements from 1 km-am paths to much longer paths at lower pressures. It could also be due to changes in the single scattering phase functions at low altitudes

  6. Laboratory studies of reactions of atmospheric gases with components of mineral dust aerosol and research in chemical education

    Science.gov (United States)

    Schuttlefield, Jennifer Dianne

    Mineral dust aerosol surfaces provide a medium in the atmosphere for heterogeneous chemistry to occur, which can alter the chemical balance of the Earth's atmosphere. It is becoming increasingly clear that the heterogeneous chemistry of these aerosols is a function of relative humidity (RH), as water on the surface of these particles can enhance or inhibit reactivity depending on the reaction. In this thesis, the uptake of water on clays and oxides was investigated, as well as phase transitions for atmospherically relevant salts. Reactions of carbon dioxide and nitric acid on oxide particles in the presence and absence of water were also examined. Following the reaction of HNO 3 on an alumina surface, photoirradiation experiments were preformed to determine the effect of irradiation on the adsorbed nitrate. The results presented in this thesis provide insight into the heterogeneous reactivity of mineral dust aerosol in the presence and absence of co-adsorbed water, as well as a fundamental understanding of water uptake on soluble and insoluble aerosols. A new method, using a quartz crystal microbalance, was developed to attempt to obtain a better fundamental understanding of different mineral dust components. In addition to the laboratory research, research in chemical education is also presented in this thesis. Two different types of work being done in the area of chemical education are shown. First a new experiment was implemented into an undergraduate physical chemistry course. The technique, ATR-FTIR spectroscopy, was chosen for its ability to expose students to a technique that is commonly used in laboratory research as well as the ease for which high quality results can be obtained. Students used ATR-FTIR spectroscopy to monitor sulfate, SO 42-, adsorption on TiO2 thin films. Second, the role of cognitive load and problem difficulty was accessed with data acquired while students completed an introductory-level chemistry word problem using a web-based tool

  7. Atomic Force Microscopy-Infrared Spectroscopy of Individual Atmospheric Aerosol Particles: Subdiffraction Limit Vibrational Spectroscopy and Morphological Analysis.

    Science.gov (United States)

    Bondy, Amy L; Kirpes, Rachel M; Merzel, Rachel L; Pratt, Kerri A; Banaszak Holl, Mark M; Ault, Andrew P

    2017-09-05

    Chemical analysis of atmospheric aerosols is an analytical challenge, as aerosol particles are complex chemical mixtures that can contain hundreds to thousands of species in attoliter volumes at the most abundant sizes in the atmosphere (∼100 nm). These particles have global impacts on climate and health, but there are few methods available that combine imaging and the detailed molecular information from vibrational spectroscopy for individual particles <500 nm. Herein, we show the first application of atomic force microscopy with infrared spectroscopy (AFM-IR) to detect trace organic and inorganic species and probe intraparticle chemical variation in individual particles down to 150 nm. By detecting photothermal expansion at frequencies where particle species absorb IR photons from a tunable laser, AFM-IR can study particles smaller than the optical diffraction limit. Combining strengths of AFM (ambient pressure, height, morphology, and phase measurements) with photothermal IR spectroscopy, the potential of AFM-IR is shown for a diverse set of single-component particles, liquid-liquid phase separated particles (core-shell morphology), and ambient atmospheric particles. The spectra from atmospheric model systems (ammonium sulfate, sodium nitrate, succinic acid, and sucrose) had clearly identifiable features that correlate with absorption frequencies for infrared-active modes. Additionally, molecular information was obtained with <100 nm spatial resolution for phase separated particles with a ∼150 nm shell and 300 nm core. The subdiffraction limit capability of AFM-IR has the potential to advance understanding of particle impacts on climate and health by improving analytical capabilities to study water uptake, heterogeneous reactivity, and viscosity.

  8. Gas-particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology.

    Science.gov (United States)

    Shiraiwa, Manabu; Zuend, Andreas; Bertram, Allan K; Seinfeld, John H

    2013-07-21

    Atmospheric aerosols, comprising organic compounds and inorganic salts, play a key role in air quality and climate. Mounting evidence exists that these particles frequently exhibit phase separation into predominantly organic and aqueous electrolyte-rich phases. As well, the presence of amorphous semi-solid or glassy particle phases has been established. Using the canonical system of ammonium sulfate mixed with organics from the ozone oxidation of α-pinene, we illustrate theoretically the interplay of physical state, non-ideality, and particle morphology affecting aerosol mass concentration and the characteristic timescale of gas-particle mass transfer. Phase separation can significantly affect overall particle mass and chemical composition. Semi-solid or glassy phases can kinetically inhibit the partitioning of semivolatile components and hygroscopic growth, in contrast to the traditional assumption that organic compounds exist in quasi-instantaneous gas-particle equilibrium. These effects have significant implications for the interpretation of laboratory data and the development of improved atmospheric air quality and climate models.

  9. Atmospheric Aerosol Chemical Composition Measurements for the Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS)

    Science.gov (United States)

    Talbot, Robert W.; Dibb, Jack E.

    1998-01-01

    We received funding to provide measurements of the chemical composition of aerosols aboard the NASA Ames DC-8 research aircraft during the SUCCESS mission. These measurements were successfully completed and the final data resides in the Cloud I computer archive at NASA Ames Research Center. The interpretation of the data obtained on this mission over the central United States has been published in special issues of Geophysical Research Letters. The papers with the University of New Hampshire as first author constitute this report and summarize the salient features of our data. The paper by Talbot et al. discusses the impact of vertical transport on free tropospheric chemistry over the the central USA in springtime. This transport was a dominant feature of the aerosol chemistry during SUCCESS. The paper by Dibb et al. discusses aerosol chemistry specifically as it related to free tropospheric sulfate related to jet exhaust and surface sources. Somewhat surprisingly, we found that surface sources appeared to dominant the distribution of aerosol sulfate in the free troposphere. In addition to these first authored papers, researchers from the University of New Hampshire were co-authors on numerous other companion papers in the special issues.

  10. Natural versus anthropogenic inhalable aerosol chemistry of transboundary East Asian atmospheric outflows into western Japan

    NARCIS (Netherlands)

    Moreno, T.; Kojima, T.; Querol, X.; Alastuey, A.; Amato, F.; Gibbons, W.

    2012-01-01

    The eastward transport of aerosols exported from mainland Asia strongly influences air quality in the Japanese archipelago. The bulk of the inhalable particulate matter (PM10) in these intrusions comprises either natural, desert-derived minerals (mostly supermicron silicates) or anthropogenic

  11. Chemical properties and morphology of Marine Aerosol in the Mediterranean atmosphere: a mesocosm study

    Science.gov (United States)

    D'Anna, Barbara; Sellegri, Karine; Charrière, Bruno; Sempéré, Richard; Mas, Sébastien; Marchand, Nicolas; George, Christian; Même, Aurèlie; R'mili, Badr; Delmont, Anne; Schwier, Allison; Rose, Clémence; Colomb, Aurèlie; Pey, Jorge; Langley Dewitt, Helen

    2014-05-01

    The Mediterranean Sea is a special marine environment characterized by low biological activity and high anthropogenic pressure. It is often difficult to discriminate the contribution of Primary Sea Salt Aerosol formed at the sea surface from background level of the aerosol. An alternative tool to study the sea-air exchanges in a controlled environment is provided by the mesocosms, which represent an important link between field studies and laboratory experiments. The sea-air transfer of particles and gases was investigated in relation to water chemical composition and biological activity during a mesocosm experiment within the SAM project (Sources of marine Aerosol in the Mediterranean) at the Oceanographic and Marine Station STARESO in Western Corsica (May 2013). Three 2 m mesocosms were filled with screened (virus, phytoplankton and zooplankton) analyses. Both dissolved and gaseous VOCs were also analyzed. In addition, few liters of seawater from each mesocosm were daily and immediately collected and transferred to a bubble-bursting apparatus to simulate nascent sea spray aerosol. On-line chemical analysis of the sub-micrometer fraction was performed by a TOF-AMS (Aerodyne). Off-line analysis included TEM-EDX for morphology and size distribution studies and a hybrid quadrupole-orbitrap mass spectrometer (Thermo Fischer) for molecular identification of the organic fraction.

  12. Impacts of aerosol direct effects on tropospheric ozone through changes in atmospheric dynamics and photolysis rates

    Science.gov (United States)

    Aerosol direct effects (ADE), i.e., scattering and absorption of incoming solar radiation, reduce radiation reaching the ground and the resultant photolysis attenuation can decrease O3 formation in polluted areas. One the other hand, evidence also suggests that ADE associated coo...

  13. Modeling aerosol impacts on atmospheric visibility in Beijing with RAMS-CMAQ

    Science.gov (United States)

    Han, Xiao; Zhang, Meigen; Tao, Jinhua; Wang, Lili; Gao, Jian; Wang, Shulan; Chai, Fahe

    2013-06-01

    A typical heavy air pollution episode occurred over the North China Plain (NCP) in December 2010. The air quality in Beijing and its surrounding regions worsened during the period December 17 to 22, and local visibility became significantly affected by the high pollution levels. The air quality modeling system RAMS-CMAQ coupled with an aerosol optical property scheme was applied to simulate the trace gases and major aerosol components in the NCP to obtain an in-depth understanding of the relationship between regional low visibility and aerosol particles. The model performance was evaluated using various observation data, such as meteorological factors (temperature, relative humidity, and wind field), gaseous pollutants (SO2, NO2, and O3), PM2.5, PM10, and visibility at several measurement stations. The modeled meteorological field and visibility were in good agreement with observations from December 2010. The modeled mass concentrations of gaseous pollutants and aerosol particles also suitably captured the magnitude and variation features of the observation data, especially during the air pollution episode. The simulated results showed that during this pollution episode, low visibility (lower than 10 km) occurred mainly in Beijing, Tianjin, Hebei, and Shandong. The analysis and sensitivity test indicated that the aerosol particles larger than PM2.5 and the water uptake effect of aerosol optical properties could not significantly influence visibility. Thus, the low visibility was primarily caused by the high mass burden of PM2.5as a result of the local pollutant accumulation and long-range transport. Statistics showed that the visibility variation was closely inversely related to the variation in PM2.5 in most regions in the NCP. Visibility decreased lower than 10 km when the mass concentration of PM2.5 exceeded 75 μg m-3 to 85 μg m-3 in the NCP. Sulfate and nitrate were the two major inorganic aerosol components of PM2.5 that evidently decreased visibility by

  14. A lidar study of atmospheric aerosols during two contrasting monsoon seasons

    Energy Technology Data Exchange (ETDEWEB)

    Devara, P.C.S.; Raj, P.E. [Indian Institute of Tropical Meteorology (India)

    1998-10-01

    The vertical profiles of the boundary-layer aerosols obtained with a bistatic argon ion lidar system at the Indian Institute of Tropical Meteorology (IITM), Pune, India, during two contrasting, successive south-west (summer) monsoon seasons of 1987 (weak monsoon year) and 1988 (active monsoon year) have been examined. The concurrent meteorological parameters such as temperature, relative humidity and rainfall over Pune have also been studied. It is noticed that the aerosol columnar content (integration of vertical profile throughout the height range) is greater during the active monsoon months and less during the weak monsoon months. Thus the monsoon season total rainfall during 1987 and 1988, apart from other meteorological parameters, shows close correspondence with the aerosol columnar content over the experimental station. A brief description of the lidar experimental setup and the database is given. The observed association between the aerosol columnar content and the monsoon activity is explained in terms of the environmental and meteorological conditions prevailing over Pune. [Spanish] Los perfiles verticales de los aerosoles de la capa fronteriza obtenidos mediante un sistema de Lidar biestatico de iones de argon en el Instituto de Meteorologia Tropical (IITM) en Pune, India, durante dos estaciones contrastantes y suscesivas del monzon del SW (verano) de 1987 (ano de monzon debil) y 1988 (ano activo de monzon) han sido estudiados. Los parametros meteorologicos concurrentes tales como temperatura, humedad relativa y lluvia en Pune, han sido tambien estudiados. Se observa que el contenido columnar de aerosoles (integracion del perfil vertical en toda la gama de alturas) es mayor durante los meses del monzon activo y menor en los meses del monzon debil. De manera que, el total de la lluvia monzonica durante 1987 y 1988, aparte de otros parametros meteorologicos, muestran una correspondencia intima con el contenido columnar de a erosoles sobre la estacion

  15. Atmospheric lifetime of caesium-137 as an estimate of aerosol lifetime -quantified from global measurements in the months after the Fukushima Dai-ichi nuclear accident

    Science.gov (United States)

    Iren Kristiansen, Nina; Stohl, Andreas; Wotawa, Gerhard

    2013-04-01

    Radionuclides like caesium-137 (137Cs) can be emitted to the atmosphere in great quantities during nuclear accidents and are of significant health impact. A global set of radionuclide measurements collected over several months after the accidental release from the Fukushima Dai-ichi nuclear power plant in March 2011 has been used to estimate the atmospheric lifetime of 137Cs. Lifetime is here defined as the e-folding time scale (the time interval in which the exponential decay of the 137Cs quantity has decreased by factor of e). The estimated atmospheric lifetime of 137Cs can also be used as an estimate of the lifetime of aerosols in the atmosphere. This is based on the fact that 137Cs attaches to the ambient accumulation-mode (AM) aerosols and trace their fate in the atmosphere. The 137Cs "tags" the AM aerosols and both the 137Cs and AM aerosols are removed simultaneously from the atmosphere by scavenging within clouds, precipitation and dry deposition. The 137Cs emitted from Fukushima attached mainly to sulphate aerosols in the size range 0.1-2 μm diameter. Measured 137Cs activity concentrations from several stations spread mostly over the Northern Hemisphere were evaluated, and the decrease in activity concentrations over time (after correction for radioactive decay) reflects the removal of aerosols by wet and dry deposition. Corrections for air mass transport were made using measurements of the noble gas xenon-133 (133Xe) which was also released during the accident. This noble gas does not attach to the aerosols and was thus used as a passive tracer of air mass transport. The atmospheric lifetime of 137Cs was estimated to 10.0-13.9 days during April and May 2011. This represents the atmospheric lifetime of a "background" AM aerosol well mixed in the extratropical northern hemisphere troposphere. It is expected that the lifetime of this vertically mixed background aerosol is longer than the lifetime of fresh AM aerosols directly emitted from surface sources

  16. Toward Quantifying the Mass-Based Hygroscopicity of Individual Submicron Atmospheric Aerosol Particles with STXM/NEXAFS and SEM/EDX

    Science.gov (United States)

    Yancey Piens, D.; Kelly, S. T.; OBrien, R. E.; Wang, B.; Petters, M. D.; Laskin, A.; Gilles, M. K.

    2014-12-01

    The hygroscopic behavior of atmospheric aerosols influences their optical and cloud-nucleation properties, and therefore affects climate. Although changes in particle size as a function of relative humidity have often been used to quantify the hygroscopic behavior of submicron aerosol particles, it has been noted that calculations of hygroscopicity based on size contain error due to particle porosity, non-ideal volume additivity and changes in surface tension. We will present a method to quantify the hygroscopic behavior of submicron aerosol particles based on changes in mass, rather than size, as a function of relative humidity. This method results from a novel experimental approach combining scanning transmission x-ray microscopy with near-edge x-ray absorption fine spectroscopy (STXM/NEXAFS), as well as scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDX) on the same individual particles. First, using STXM/NEXAFS, our methods are applied to aerosol particles of known composition ‒ for instance ammonium sulfate, sodium bromide and levoglucosan ‒ and validated by theory. Then, using STXM/NEXAFS and SEM/EDX, these methods are extended to mixed atmospheric aerosol particles collected in the field at the DOE Atmospheric Radiation Measurement (ARM) Climate Research Facility at the Southern Great Planes sampling site in Oklahoma, USA. We have observed and quantified a range of hygroscopic behaviors which are correlated to the composition and morphology of individual aerosol particles. These methods will have implications for parameterizing aerosol mixing state and cloud-nucleation activity in atmospheric models.

  17. Final Report "Nucleation and Growth of Atmospheric Aerosols" DOE Grant No. DE-FG02-98ER62556

    Energy Technology Data Exchange (ETDEWEB)

    McMurry, Peter H. [Univ. of Minnesota, Minneapolis, MN (United States); Eisele, Fred L. [Univ. of Minnesota, Minneapolis, MN (United States)

    2005-06-02

    observed when L was less than one and not when L was greater than one; (3) growth rates of freshly nucleated particles could be explained by condensation of sulfuric acid and coagulation of the newly formed nucleation mode in the mornings when particles were small (<20 nm), but at midday when particles had growth to larger sizes measured growth rates were often five times greater than calculated growth rates suggesting that species in addition to sulfuric acid were contributing to growth. This contract also supported TDCIMS and aerosol physical property measurements performed at NCAR's Mesa Laboratory in Boulder, CO, intermittently since the Spring of 2002. The TDCIMS measurements were made on sub-20 nm diameter atmospheric particles, and have uncovered many intriguing questions that warrant further investigation. For example, unlike the case in Atlanta where primarily ammonium was observed in the positive ion spectrum for ambient aerosol, Boulder aerosols appear to be composed of a variety of compounds most of which have not been identified. In the negative ion spectrum, Boulder sub-20 nm diameter particles are characterized by large nitrate peaks, with integrated areas up to 3 orders of magnitude greater than aerosol sulfate.

  18. Regional and local variations in atmospheric aerosols using ground-based sun photometry during Distributed Regional Aerosol Gridded Observation Networks (DRAGON in 2012

    Directory of Open Access Journals (Sweden)

    I. Sano

    2016-11-01

    Full Text Available Aerosol mass concentrations are affected by local emissions as well as long-range transboundary (LRT aerosols. This work investigates regional and local variations of aerosols based on Distributed Regional Aerosol Gridded Observation Networks (DRAGON. We constructed DRAGON-Japan and DRAGON-Osaka in spring of 2012. The former network covers almost all of Japan in order to obtain aerosol information in regional scale over Japanese islands. It was determined from the DRAGON-Japan campaign that the values of aerosol optical thickness (AOT decrease from west to east during an aerosol episode. In fact, the highest AOT was recorded at Fukue Island at the western end of the network, and the value was much higher than that of urban areas. The latter network (DRAGON-Osaka was set as a dense instrument network in the megalopolis of Osaka, with a population of 12 million, to better understand local aerosol dynamics in urban areas. AOT was further measured with a mobile sun photometer attached to a car. This transect information showed that aerosol concentrations rapidly changed in time and space together when most of the Osaka area was covered with moderate LRT aerosols. The combined use of the dense instrument network (DRAGON-Osaka and high-frequency measurements provides the motion of aerosol advection, which coincides with the wind vector around the layer between 700 and 850 hPa as provided by the reanalysis data of the National Centers for Environmental Prediction (NCEP.

  19. European isotopic signatures for lead in atmospheric aerosols. A source apportionment based upon 206Pb/207Pb ratios

    Energy Technology Data Exchange (ETDEWEB)

    Flament, Pascal; Deboudt, Karine [Laboratoire de Biogeochimie et Environnement du Littoral (LABEL), Universite du Littoral-Cote d' Opale, CNRS/INSU 8013 ' ELICO' , 32 Avenue Foch, F-62930 Wimereux (France); Bertho, Marie-Laure; Puskaric, Emile [Laboratoire Interdisciplinaire en Sciences de l' Environnement (LISE), Universite du Littoral-Cote d' Opale, CNRS/INSU 8013 ' ELICO' , 32 Avenue Foch, F-62930 Wimereux (France); Veron, Alain [Universite d' Aix-Marseille III, Geosciences de l' Environnement (UMR CNRS 6536) CEREGE, BP 80, F-13545 Cedex 4 Aix en Provence (France)

    2002-09-16

    To investigate the capability of the lead isotope signature technique to support a source apportionment study at a Continental scale, atmospheric particulate matter was collected at Cap Gris-Nez (Eastern Channel, northern France), over one year (1995-1996). Four days retrospective trajectories of air masses were available during each sampling experiment. Twenty-eight samples, for which the origin of aerosols was unambiguously determined, were selected for isotopic measurements. Considering the Enrichment Factors, EF{sub Crust} of lead and its size distribution, we show that lead is mostly from anthropogenic origin and mainly associated with [0.4aerosols is exhibited by considering both the lead concentration and the origin of air masses. Lead concentration is higher by a factor of approximately seven, when air masses are derived from Continental Europe, by comparison with marine air masses. Taking into account these concentrations and the vertical movements of air masses, we compare the different isotopic compositions using a statistical non-parametric test (Kolmogorov-Smirnov). We produce evidence that, for most of the cases, air masses originating from Continental Europe exhibit a more radiogenic composition (1.134<{sup 206}Pb/207Pb<1.172) than air masses coming from the United Kingdom (1.106<{sup 206}Pb/207Pb<1.124). Generally, lead isotopic compositions in aerosols are clearly distinct from the gasoline signatures in European countries, strongly suggesting that automotive lead is no longer the major component of this metal in the air. Gasoline and industrial isotopic signatures could explain the origin of lead in our aerosol samples. A source apportionment based upon 206Pb/207Pb ratios, suggests that the difference between British (206Pb/207Pb=1.122{+-}0.038) and Continental (206Pb/207Pb=1.155{+-}0.022) signatures may be largely explained by

  20. Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Enggrob, Kirsten L.; King, S. M.

    2013-01-01

    products cis-pinic and terpenylic acids, but similar to the second-generation oxidation products 3-methyl-1,2,3-butane tricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). Dimer esters were observed within the first 30 min, indicating rapid production simultaneous to their structural......The formation of carboxylic acids and dimer esters from alpha-pinene oxidation was investigated in a smog chamber and in ambient aerosol samples collected during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX). Chamber experiments of alpha-pinene ozonolysis in dry air...... times higher during the warmer 2009 campaign relative to 2007, while the concentration of cis-pinic acid was approximately the same during both periods, and lack of correlation with levels of cis-pinic and terpenylic acids for both campaigns indicate that the formation of the pinyl-diaterpenyl ester...

  1. A novel single-cavity three-wavelength photoacoustic spectrometer for atmospheric aerosol research

    OpenAIRE

    Linke, Claudia; Ibrahim, Inas; Schleicher, Nina; Hitzenberger, Regina; Andreae, Meinrat O.; Leisner, Thomas; Schnaiter, Martin

    2016-01-01

    The spectral light-absorbing behavior of carbonaceous aerosols varies depending on the chemical composition and structure of the particles. A new single-cavity three-wavelength photoacoustic spectrometer was developed and characterized for measuring absorption coefficients at three wavelengths across the visible spectral range. In laboratory studies, several types of soot with different organic content were generated by a diffusion flame burner and were investigated for chan...

  2. Atmospheric impact of the 1783–1784 Laki Eruption: Part II Climatic effect of sulphate aerosol

    Directory of Open Access Journals (Sweden)

    E.-J. Highwood

    2003-01-01

    Full Text Available The long 1783-1784 eruption of Laki in southern Iceland, was one of the first eruptions to have been linked to an observed climate anomaly, having been held responsible for cold temperatures over much of the Northern Hemisphere in the period 1783-1785. Results from the first climate model simulation of the impact of a similar eruption to that of 1783-1784 are presented. Using sulphate aerosol fields produced in a companion chemical transport model simulation by Stevenson et al. (2003, the radiative forcing and climate response due to the aerosol are calculated here using the Reading Intermediate General Circulation Model (IGCM. The peak Northern Hemisphere mean direct radiative forcing is -5.5 Wm-2 in August 1783. The radiative forcing dies away quickly as the emissions from the volcano decrease; however, a small forcing remains over the Mediterranean until March 1784. There is little forcing in the Southern Hemisphere. There is shown to be an uncertainty of at least 50% in the direct radiative forcing due to assumptions concerning relative humidity and the sophistication of the radiative transfer code used. The indirect effects of the Laki aerosol are potentially large but essentially unquantifiable at the present time. In the IGCM at least, the aerosol from the eruption produces a climate response that is spatially very variable. The Northern Hemisphere mean temperature anomaly averaged over the whole of the calendar year containing most of the eruption is -0.21 K, statistically significant at the 95% level and in reasonable agreement with the available observations of the temperature during 1783.

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

    Science.gov (United States)

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

    2013-12-01

    The Mediterranean Sea is a special marine environment characterized by low biological activity and high anthropogenic pressure. It is often difficult to discriminated the contribution of Primary Sea Salt Aerosol (SSA) formed at the sea-air interface from background level of the aerosol. An alternative tool to study the sea-air exchanges in a controlled environment is provided by the mesocosms, which represent an important link between field studies and laboratory experiments. A mesocosms experiment was performed in May 2013 at the Oceanographic and Marine Station STARESO in Western Corsica. Three mesocosms were simultaneously filled with pooled and screened (virus, phytoplankton and zooplankton concentration) analyses. Finally, few liters of sea-water from each mesocosms were sampled daily and immediately transferred to a bubble-bursting apparatus to simulate SSA. Size distribution and particle number were followed by SMPS and APS in the range of 10nm to 10μm. The hygroscopic properties were investigated by a CCN device. On-line chemical analysis of the sub-micrometer fraction was performed by a c-TOF-AMS. Off-line analysis of the SSA generated included TEM-EDX , LC-MS and IC, Thermo-optical analysis of EC-OC. The objective of the present study is to investigate the influence of water chemical and biological composition and biological activity on physical and chemical properties of the primary generated aerosol.

  4. A novel single-cavity three-wavelength photoacoustic spectrometer for atmospheric aerosol research

    Directory of Open Access Journals (Sweden)

    C. Linke

    2016-11-01

    Full Text Available The spectral light-absorbing behavior of carbonaceous aerosols varies depending on the chemical composition and structure of the particles. A new single-cavity three-wavelength photoacoustic spectrometer was developed and characterized for measuring absorption coefficients at three wavelengths across the visible spectral range. In laboratory studies, several types of soot with different organic content were generated by a diffusion flame burner and were investigated for changes in mass-specific absorption cross section (MAC values, absorption and scattering Ångström exponents (αabs and αsca, and single scattering albedo (ω. By increasing the organic carbonaceous (OC content of the aerosol from 50 to 90 % of the total carbonaceous mass, for 660 nm nearly no change of MAC was found with increasing OC content. In contrast, for 532 nm a significant increase, and for 445 nm a strong increase of MAC was found with increasing OC content of the aerosol. Depending on the OC content, the Ångström exponents of absorption and scattering as well as the single scattering albedo increased. These laboratory results were compared to a field study at a traffic-dominated urban site, which was also influenced by residential wood combustion. For this site a daily average value of αabs(445–660 of 1.9 was found.

  5. A novel single-cavity three-wavelength photoacoustic spectrometer for atmospheric aerosol research

    Science.gov (United States)

    Linke, Claudia; Ibrahim, Inas; Schleicher, Nina; Hitzenberger, Regina; Andreae, Meinrat O.; Leisner, Thomas; Schnaiter, Martin

    2016-11-01

    The spectral light-absorbing behavior of carbonaceous aerosols varies depending on the chemical composition and structure of the particles. A new single-cavity three-wavelength photoacoustic spectrometer was developed and characterized for measuring absorption coefficients at three wavelengths across the visible spectral range. In laboratory studies, several types of soot with different organic content were generated by a diffusion flame burner and were investigated for changes in mass-specific absorption cross section (MAC) values, absorption and scattering Ångström exponents (αabs and αsca), and single scattering albedo (ω). By increasing the organic carbonaceous (OC) content of the aerosol from 50 to 90 % of the total carbonaceous mass, for 660 nm nearly no change of MAC was found with increasing OC content. In contrast, for 532 nm a significant increase, and for 445 nm a strong increase of MAC was found with increasing OC content of the aerosol. Depending on the OC content, the Ångström exponents of absorption and scattering as well as the single scattering albedo increased. These laboratory results were compared to a field study at a traffic-dominated urban site, which was also influenced by residential wood combustion. For this site a daily average value of αabs(445-660) of 1.9 was found.

  6. Reactions of SIV species with organic compounds: formation mechanisms of organo-sulfur derivatives in atmospheric aerosols

    Science.gov (United States)

    Passananti, Monica; Shang, Jing; Dupart, Yoan; Perrier, Sébastien; George, Christian

    2015-04-01

    Secondary organic aerosol (SOA) have an important impact on climate, air quality and human health. However the chemical reactions involved in their formation and growth are not fully understood or well-constrained in climate models. It is well known that inorganic sulfur (mainly in oxidation states (+IV) and (+VI)) plays a key role in aerosol formation, for instance sulfuric acid is known to be a good nucleating gas. In addition, acid-catalyzed heterogeneous reactions of organic compounds has shown to produce new particles, with a clear enhancement in the presence of ozone (Iinuma 2013). Organosulfates have been detected in tropospheric particles and aqueous phases, which suggests they are products of secondary organic aerosol formation process (Tolocka 2012). Originally, the production of organosulfates was explained by the esterification reaction of alcohols, but this reaction in atmosphere is kinetically negligible. Other formation pathways have been suggested such as hydrolysis of peroxides and reaction of organic matter with sulfite and sulfate radical anions (SO3-, SO4-) (Nozière 2010), but it remains unclear if these can completely explain atmospheric organo-sulfur aerosol loading. To better understand the formation of organo-sulfur compounds, we started to investigate the reactivity of SIV species (SO2 and SO32-) with respect to specific functional groups (organic acids and double bonds) on atmospherically relevant carboxylic acids and alkenes. The experiments were carried out in the homogeneous aqueous phase and at the solid-gas interface. A custom built coated-wall flow tube reactor was developed to control relativity humidity, SO2 concentration, temperature and gas flow rate. Homogeneous and heterogeneous reaction kinetics were measured and resulting products were identified using liquid chromatography coupled with an orbitrap mass spectrometer (LC-HR-MS). The experiments were performed with and without the presence of ozone in order to evaluate any

  7. Optical properties and chemical composition of the atmospheric aerosol in urban Guangzhou, China

    Science.gov (United States)

    Andreae, Meinrat O.; Schmid, Otmar; Yang, Hong; Chand, Duli; Zhen Yu, Jian; Zeng, Li-Min; Zhang, Yuan-Hang

    During the Pearl River Delta measurement campaign (Program of Regional Integrated Experiments of Air Quality over Pearl River Delta 2004, PRIDE-PRD2004, 4 October-5 November 2004), we measured aerosol light absorption and scattering (PM2.5) in urban Guangzhou, using a photoacoustic spectrometer and two integrating nephelometers (at ambient and dry humidity). In addition, 12-h averages of elemental carbon (EC a), organic carbon (OC), and inorganic species concentrations were determined. Aerosol concentrations in urban Guangzhou were extremely high, with average PM2.5, OC, and EC a concentrations of 103, 22.4, and 7.1 μg m -3, respectively. The chemical composition of the aerosol was dominated by particulate organic matter, EC a, sulfate and ammonium. Elevated levels of potassium indicated significant contributions from biomass burning to the regional haze. The high average OC/EC a ratio of 3.6±1.1 resulted from a mixture of regional haze with high OC content and local emissions with low OC/EC a, mostly from vehicular sources. The average scattering and absorption coefficients for dry aerosol were 418 and 91 Mm -1 ( λ˜540 nm), and the mean mass scattering and absorption efficiencies 4.2±1.0 and 0.78±0.19 m 2 g -1. During some episodes resulting from the trapping of local emissions in a nocturnal boundary layer, extreme values of aerosol absorption were reached (up to 490 Mm -1). The average single scattering albedo ( ω0, λ˜540 nm) at dry conditions was about 0.83, representing a mixture of fresh, strongly absorbing, urban pollution, and a more scattering regional haze. Because of the prevailing low humidity, the ambient ω0 was not significantly higher. The mass absorption efficiency of EC a was 7.7 m 2 g -1; an additional contribution to absorption was associated with OC, either as a result of light absorption by OC or the effects of internal mixing. The observed diurnal trends of the optical and chemical properties are consistent with aged regional haze

  8. Gas/Aerosol partitioning: a simplified method for global modeling

    NARCIS (Netherlands)

    Metzger, S.M.

    2000-01-01

    The main focus of this thesis is the development of a simplified method to routinely calculate gas/aerosol partitioning of multicomponent aerosols and aerosol associated water within global atmospheric chemistry and climate models. Atmospheric aerosols are usually multicomponent mixtures,

  9. Comparative study of pretreatment methods for the determination of metals in atmospheric aerosol by electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Karanasiou, A A; Thomaidis, N S; Eleftheriadis, K; Siskos, P A

    2005-03-15

    A comparative study of pretreatment methods for the determination of 10 elements (As, Cd, Pb, V, Ni, Mn, Cr, Cu, Fe, Al) in atmospheric aerosols by electrothermal atomic absorption spectrometry (ETAAS) was conducted. For the digestion of the particulates collected in filters, six methods were compared using a mixture of HNO(3) and HF with or without the addition of various oxidative agents (HClO(4) or H(2)O(2)) or acids (HCl). The comparative study was performed using loaded cellulose filter samples, which were digested in Parr bombs and heated in a conventional oven at 170 degrees C for 5h. The extraction efficiency and blanks were compared and it was proved that the digestion method using only HNO(3)-HF extracted most of the metals and gave the lowest blanks. The HNO(3)-HF mixture was selected for the development of an improved microwave digestion method specific for aerosol-loaded filters. The operating parameters were optimized, so that quantitative recovery of the reference materials NIST 1649a urban dust and NIST 1648 urban particulate matter was achieved. The blank of cellulose and teflon filters were also determined and compared. Teflon filters present the lowest blanks for all the elements. The obtained limits of detection for each type of filters were adequate for environmental monitoring purposes. ETAAS instrumental operation was also optimized for the compensation and the elimination of interferences. The temperature optimization was performed for each metal in every type of filter and optimized parameters are proposed for 10 elements.

  10. DMS atmospheric concentrations and sulphate aerosol indirect radiative forcing: a sensitivity study to the DMS source representation and oxidation

    Directory of Open Access Journals (Sweden)

    O. Boucher

    2003-01-01

    Full Text Available The global sulphur cycle has been simulated using a general circulation model with a focus on the source and oxidation of atmospheric dimethylsulphide (DMS. The sensitivity of atmospheric DMS to the oceanic DMS climatology, the parameterisation of the sea-air transfer and to the oxidant fields have been studied. The importance of additional oxidation pathways (by O3 in the gas- and aqueous-phases and by BrO in the gas phase not incorporated in global models has also been evaluated. While three different climatologies of the oceanic DMS concentration produce rather similar global DMS fluxes to the atmosphere at 24-27 Tg S yr -1, there are large differences in the spatial and seasonal distribution. The relative contributions of OH and NO3 radicals to DMS oxidation depends critically on which oxidant fields are prescribed in the model. Oxidation by O3 appears to be significant at high latitudes in both hemispheres. Oxidation by BrO could be significant even for BrO concentrations at sub-pptv levels in the marine boundary layer. The impact of such refinements on the DMS chemistry onto the indirect radiative forcing by anthropogenic sulphate aerosols is also discussed.

  11. Lead isotopic fingerprinting of aerosols to characterize the sources of atmospheric lead in an industrial city of India

    Science.gov (United States)

    Sen, Indra S.; Bizimis, Michael; Tripathi, Sachchida Nand; Paul, Debajyoti

    2016-03-01

    Anthropogenic Pb in the environment is primarily sourced from combustion of fossil fuel and high-temperature industries such as smelters. Identifying the sources and pathways of anthropogenic Pb in the environment is important because Pb toxicity is known to have adverse effects on human health. Pb pollution sources for America, Europe, and China are well documented. However, sources of atmospheric Pb are unknown in India, particularly after leaded gasoline was phased out in 2000. India has a developing economy with a rapidly emerging automobile and high temperature industry, and anthropogenic Pb emission is expected to rise in the next decade. In this study, we report on the Pb-isotope compositions and trace metal ratios of airborne particulates collected in Kanpur, a large city in northern part of India. The study shows that the PM10 aerosols had elevated concentration of Cd, Pb, Zn, As, and Cu in the Kanpur area, however their concentrations are well below the United States Environmental Protection Agency chronic exposure limit. Lead isotopic and trace metal data reveal industrial emission as the plausible source of anthropogenic Pb in the atmosphere in Kanpur. However, Pb isotopic compositions of potential source end-members are required to fully evaluate Pb contamination in India over time. This is the first study that characterizes the isotopic composition of atmospheric Pb in an Indian city after leaded gasoline was phased out by 2000.

  12. Lidar Observation of Aerosol and Temperature Stratification over Urban Area During the Formation of a Stable Atmospheric PBL

    Science.gov (United States)

    Kolev, I.; Parvanov, O.; Kaprielov, B.; Mitev, V.; Simeonov, V.; Grigorov, I.

    1992-01-01

    In recent years, the processes in the atmospheric planetary boundary layer (PBL) over urban areas were intensely investigated, due to ecological problems related to the air, soil, and water pollution. New pollution sources in new residential districts, when in contradiction to the microclimate and topography requirements of that region, create a number of considerable hazards and problems. The present study is a continuation of our preceding investigations and aims at revealing the aerosol structure and stratification during the transition after sunset as measured by two lidars. Such observation of the nocturnal, stable PBL formation over an urban area in Bulgaria has not been reported before. The lidars' high time and spatial resolutions allow the changes of the internal structure of the PBL's part located above the surface layer to be observed.

  13. Impact of Manaus City on the Amazon Green Ocean atmosphere: ozone production, precursor sensitivity and aerosol load

    Science.gov (United States)

    Kuhn, U.; Ganzeveld, L.; Thielmann, A.; Dindorf, T.; Schebeske, G.; Welling, M.; Sciare, J.; Roberts, G.; Meixner, F. X.; Kesselmeier, J.; Lelieveld, J.; Kolle, O.; Ciccioli, P.; Lloyd, J.; Trentmann, J.; Artaxo, P.; Andreae, M. O.

    2010-10-01

    As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001) field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry season transition period in July 2001. During the flights, we performed vertical stacks of crosswind transects in the urban outflow downwind of Manaus City, measuring a comprehensive set of trace constituents including O3, NO, NO2, CO, VOC, CO2, and H2O. Aerosol loads were characterized by concentrations of total aerosol number (CN) and cloud condensation nuclei (CCN), and by light scattering properties. Measurements over pristine rainforest areas during the campaign showed low levels of pollution from biomass burning or industrial emissions, representative of wet season background conditions. The urban plume of Manaus City was found to be joined by plumes from power plants south of the city, all showing evidence of very strong photochemical ozone formation. One episode is discussed in detail, where a threefold increase in ozone mixing ratios within the atmospheric boundary layer occurred within a 100 km travel distance downwind of Manaus. Observation-based estimates of the ozone production rates in the plume reached 15 ppb h-1. Within the plume core, aerosol concentrations were strongly enhanced, with ΔCN/ΔCO ratios about one order of magnitude higher than observed in Amazon biomass burning plumes. ΔCN/ΔCO ratios tended to decrease with increasing transport time, indicative of a significant reduction in particle number by coagulation, and without substantial new particle nucleation occurring within the time/space observed. While in the background atmosphere a large fraction of the total particle number served as CCN (about 60-80% at 0.6% supersaturation), the CCN/CN ratios within the plume indicated that only a small fraction (16±12%) of the plume particles were CCN

  14. Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry in the identification of organic compounds in atmospheric aerosols from coniferous forest

    NARCIS (Netherlands)

    Kallio, M.; Jussila, M.; Rissanen, T.; Anttila, P.; Hartonen, K.; Reissell, A.; Vreuls, R.J.J.; Adahchour, M.; Hyotylainen, T.

    2006-01-01

    Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF-MS) was applied in the identification of organic compounds in atmospheric aerosols from coniferous forest. The samples were collected at Hyytiälä, Finland, as part of the QUEST campaign, in

  15. Elemental and Organic Carbon in Atmospheric Aerosols at Two Urban Background Sites in Prague

    Czech Academy of Sciences Publication Activity Database

    Schwarz, Jaroslav; Chi, X.; Maenhaut, W.; Civiš, M.; Hovorka, J.; Smolík, Jiří

    2008-01-01

    Roč. 99, 2-4 (2008), s. 287-302 ISSN 0169-8095 R&D Projects: GA ČR GA205/03/1560; GA MŠk OC 106; GA MŠk ME 941; GA MŽP(CZ) SM/9/86/05 Institutional research plan: CEZ:AV0Z40720504 Keywords : organic and elemental carbon * urban aerosols * air mass trajectory Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.456, year: 2008

  16. Contribution of carbonyl photochemistry to aging of atmospheric secondary organic aerosol

    DEFF Research Database (Denmark)

    Mang, Stephen A.; Henricksen, Dana K.; Bateman, Adam P.

    2008-01-01

    The photodegradation of secondary organic aerosol (SOA) material by actinic UV radiation was investigated. SOA was generated via the dark reaction of ozone and d-limonene, collected onto quartz-fiber filters, and exposed to wavelength-tunable radiation. Photochemical production of CO was monitored...... was measured and compared with the photolysis action spectrum for the release of CO, a marker for Norrish type-1 photocleavage of carbonyls. Both spectra had a band at similar to 300 nm corresponding to the overlapping n -> pi* transitions in nonconjugated carbonyls. The effective extinction coefficient...

  17. Effect of surface albedo, water vapour, and atmospheric aerosols on the cloud-free shortwave radiative budget in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Di Biagio, C. [ENEA, Laboratory for Earth Observations and Analyses, Rome (Italy); University of Siena, Department of Earth Science, Siena (Italy); Di Sarra, A. [ENEA, Laboratory for Earth Observations and Analyses, Rome (Italy); Eriksen, P. [Danish Climate Centre, DMI, Danish Meteorological Institute, Copenhagen (Denmark); Ascanius, S.E. [DMI, Danish Meteorological Institute, Qaanaaq (Greenland); Muscari, G. [INGV, Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy); Holben, B. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2012-08-15

    This study is based on ground-based measurements of downward surface shortwave irradiance (SW), columnar water vapour (wv), and aerosol optical depth ({tau}) obtained at Thule Air Base (Greenland) in 2007-2010, together with MODIS observations of the surface shortwave albedo (A). Radiative transfer model calculations are used in combination with measurements to separate the radiative effect of A ({Delta}SW{sub A}), wv ({Delta}SW{sub wv}), and aerosols ({Delta}SW{sub {tau}}) in modulating SW in cloud-free conditions. The shortwave radiation at the surface is mainly affected by water vapour absorption, which produces a reduction of SW as low as -100 Wm{sup -2} (-18%). The seasonal change of A produces an increase of SW by up to +25 Wm{sup -2} (+4.5%). The annual mean radiative effect is estimated to be -(21-22) Wm{sup -2} for wv, and +(2-3) Wm{sup -2} for A. An increase by +0.065 cm in the annual mean wv, to which corresponds an absolute increase in {Delta}SW{sub wv} by 0.93 Wm{sup -2} (4.3%), has been observed to occur between 2007 and 2010. In the same period, the annual mean A has decreased by -0.027, with a corresponding decrease in {Delta}SW{sub A} by 0.41 Wm{sup -2} (-14.9%). Atmospheric aerosols produce a reduction of SW as low as -32 Wm{sup -2} (-6.7%). The instantaneous aerosol radiative forcing (RF{sub {tau}}) reaches values of -28 Wm{sup -2} and shows a strong dependency on surface albedo. The derived radiative forcing efficiency (FE{sub {tau}}) for solar zenith angles between 55 and 70 is estimated to be (-120.6 {+-} 4.3) for 0.1 < A < 0.2, and (-41.2 {+-} 1.6) Wm{sup -2} for 0.5 < A < 0.6. (orig.)

  18. Evaluation of a global aerosol microphysics model against size-resolved particle statistics in the marine atmosphere

    Directory of Open Access Journals (Sweden)

    D. V. Spracklen

    2007-01-01

    Full Text Available A statistical synthesis of marine aerosol measurements from experiments in four different oceans is used to evaluate a global aerosol microphysics model (GLOMAP. We compare the model against observed size resolved particle concentrations, probability distributions, and the temporal persistence of different size particles. We attempt to explain the observed sub-micrometre size distributions in terms of sulfate and sea spray and quantify the possible contributions of anthropogenic sulfate and carbonaceous material to the number and mass distribution. The model predicts a bimodal size distribution that agrees well with observations as a grand average over all regions, but there are large regional differences. Notably, observed Aitken mode number concentrations are more than a factor 10 higher than in the model for the N Atlantic but a factor 7 lower than the model in the NW Pacific. We also find that modelled Aitken mode and accumulation mode geometric mean diameters are generally smaller in the model by 10–30%. Comparison with observed free tropospheric Aitken mode distributions suggests that the model underpredicts growth of these particles during descent to the marine boundary layer (MBL. Recent observations of a substantial organic component of free tropospheric aerosol could explain this discrepancy. We find that anthropogenic continental material makes a substantial contribution to N Atlantic MBL aerosol, with typically 60–90% of sulfate across the particle size range coming from anthropogenic sources, even if we analyse air that has spent an average of >120 h away from land. However, anthropogenic primary black carbon and organic carbon particles (at the emission size and quantity assumed here do not explain the large discrepancies in Aitken mode number. Several explanations for the discrepancy are suggested. The lack of lower atmospheric particle formation in the model may explain low N Atlantic particle concentrations. However, the

  19. Effects of aerosol phase function and other atmospheric parameters in radiometric calibration of hyperspectral visible/NIR satellite instruments above test sites of different altitudes

    Science.gov (United States)

    Postylyakov, Oleg; Borovski, Alexander

    2017-10-01

    To verify data obtained by a satellite instrument a systematic calibration of the instrument is carried out. In addition to an internal calibration using on-board lamp or reflected solar radiation, the external calibration based on a comparison of radiance measurements above special ground test sites and calculated radiances is often employed. Radiances at the top of the atmosphere can be calculated using a radiative transfer model basing on measurement of the atmospheric properties and surface characteristics at the test sites. External calibration of hyperspectral instrument is sensitive to the spectral structure of absorbing and scattering of atmospheric species and, as a consequence, has a specific spectral structure of errors. We compared theoretical errors of a satellite hyperspectral instrument radiometric calibration using two test sites one of which is located in downcountry at 200 m a.s.l. and another one in highlands at 2000 m a.s.l. We suppose that both stations are equipped by the same set of instruments for measurements of the properties of the atmosphere and surface reflectance. The aerosol vertical profile and the aerosol phase function are supposed as not measured characteristics. The analysis is performed for an instrument with the spectral resolution of 1-8 nm which is typical for special regime of payload GSA of Russian satellite Resurs-P. The errors related with the atmospheric composition (including possible scenarios of the aerosol phase function and the aerosol vertical profile) and albedo measurement errors were theoretically examined. The errors strongly depend on aerosol loading. In case of low aerosol loading (corresponding to aerosol optical depth of 0.1 at 0 m a.s.l.) errors are less than 10% at both sites for all the wavelengths between 400 nm and 1000 nm with the exception of the absorption band of water vapor about 950 nm, where errors reach 35% at downcountry and 14% at highlands. For aerosol optical depth of 1 at 0 m a.s.l. the

  20. Formation and occurrence of dimer esters of pinene oxidation products in atmospheric aerosols

    Directory of Open Access Journals (Sweden)

    K. Kristensen

    2013-04-01

    Full Text Available The formation of carboxylic acids and dimer esters from α-pinene oxidation was investigated in a smog chamber and in ambient aerosol samples collected during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX. Chamber experiments of α-pinene ozonolysis in dry air and at low NOx concentrations demonstrated formation of two dimer esters, pinyl-diaterpenyl (MW 358 and pinonyl-pinyl dimer ester (MW 368, under both low- and high-temperature conditions. Concentration levels of the pinyl-diaterpenyl dimer ester were lower than the assumed first-generation oxidation products cis-pinic and terpenylic acids, but similar to the second-generation oxidation products 3-methyl-1,2,3-butane tricarboxylic acid (MBTCA and diaterpenylic acid acetate (DTAA. Dimer esters were observed within the first 30 min, indicating rapid production simultaneous to their structural precursors. However, the sampling time resolution precluded conclusive evidence regarding formation from gas- or particle-phase processes. CCN activities of the particles formed in the smog chamber displayed a modest variation during the course of experiments, with κ values in the range 0.06–0.09 (derived at a supersaturation of 0.19%. The pinyl-diaterpenyl dimer ester was also observed in ambient aerosol samples collected above a ponderosa pine forest in the Sierra Nevada Mountains of California during two seasonally distinct field campaigns in September 2007 and July 2009. The pinonyl-pinyl ester was observed for the first time in ambient air during the 2009 campaign, and although present at much lower concentrations, it was correlated with the abundance of the pinyl-diaterpenyl ester, suggesting similarities in their formation. The maximum concentration of the pinyl-diaterpenyl ester was almost 10 times higher during the warmer 2009 campaign relative to 2007, while the concentration of cis-pinic acid was approximately the same during both periods, and lack of correlation

  1. Pulmonary deposition of urban atmospheric aerosol. Assessments of the mass, number and surface of the deposited particles; Deposizione polmonare dell'aerosol atmosferico urbano in termini di massa, numero e superficie delle particelle

    Energy Technology Data Exchange (ETDEWEB)

    Luciani, A.; Berico, M.; Castellani, C.M. [ENEA, Centro Ricerche Ezio Clementel, Bologna (Italy). Dipt. Ambiente

    1998-07-01

    Pulmonary deposition of urban atmospheric aerosol has been calculated by means of the data derived from March 1995 measurement campaign of urban aerosol. The human respiratory tract model of the International Commission on Radiological Protection (n. 66) developed for radiation protection purposes has been used. The number and surface of the deposited particles, as well as the mass, have been also evaluated. [Italian] I dati relativi alla campagna di misure effettuata nel marzo 1995 sono stati rielaborati al fine di valutare la deposizione polmonare dell'aerosol atmosferico in area urbana. Le valutazioni di deposizione nel tratto respiratorio umano sono state condotte mediante l'utilizzo del modello del tratto respiratorio umano presentato per fini radioprotezionistici dalla International Commission on Radiological Protection (n. 66). Sono state effettuate valutazioni di deposizione in massa e in termini di numero e superficie delle particelle.

  2. Speciation of 127I and 129I in atmospheric aerosols at Risø, Denmark: insight into sources of iodine isotopes and their species transformations

    DEFF Research Database (Denmark)

    Zhang, Luyuan; Hou, Xiaolin; Xu, Sheng

    2015-01-01

    in the aerosols are found to be strongly related to their sources and atmospheric pathways. Aerosols that were transported over the contaminated ocean, contained higher amounts of 129I than aerosols transported over the European continent. The high 129I concentrations of the marine aerosols are attributed...... to secondary emission from heavily 129I-contaminated seawater rather than primary gaseous release from nuclear reprocessing plants. Water-soluble iodine was found to be a minor fraction to total iodine for both 127I (7.8–13.7 %) and 129I (6.5–14.1 %) in ocean-derived aerosols, but accounted for 20...

  3. Speciation of 127I and 129I in atmospheric aerosols at Risø, Denmark: insight into sources of iodine isotopes and their species transformations

    DEFF Research Database (Denmark)

    Zhang, Luyuan; Hou, Xiaolin; Xu, Sheng

    2016-01-01

    in the aerosols are found to be strongly related to their sources and atmospheric pathways. Aerosols that were transported over the contaminated ocean, contained higher amounts of 129I than aerosols transported over the European continent. The high 129I concentrations of the marine aerosols are attributed...... to secondary emission from heavily 129I-contaminated seawater rather than primary gaseous release from nuclear reprocessing plants. Water-soluble iodine was found to be a minor fraction to total iodine for both 127I (7.8–13.7 %) and 129I (6.5–14.1 %) in ocean-derived aerosols, but accounted for 20...

  4. Development of an online radiative module for the computation of aerosol optical properties in 3-D atmospheric models: validation during the EUCAARI campaign

    Directory of Open Access Journals (Sweden)

    B. Aouizerats

    2010-10-01

    Full Text Available Obtaining a good description of aerosol optical properties for a physically and chemically complex evolving aerosol is computationally very expensive at present. The goal of this work is to propose a new numerical module computing the optical properties for complex aerosol particles at low numerical cost so that it can be implemented in atmospheric models. This method aims to compute the optical properties online as a function of a given complex refractive index deduced from the aerosol chemical composition and the size parameters corresponding to the particles.

    The construction of look-up tables from the imaginary and the real part of the complex refractive index and size parameters will also be explained. This approach is validated for observations acquired during the EUCAARI (European integrated project on aerosol cloud climate air quality interactions campaign on the Cabauw tower during May 2008 and its computing cost is also estimated.

    These comparisons show that the module manages to reproduce the scattering and absorbing behaviour of the aerosol during most of the fifteen-day period of observation with a very cheap computationally cost.

  5. Langley Mobile Ozone Lidar: Ozone and Aerosol Atmospheric Profiling for Air Quality Research

    Science.gov (United States)

    De Young, Russell; Carrion, William; Ganoe, Rene; Pliutau, Denis; Gronoff, Guillaume; Berkoff, Timothy; Kuang, Shi

    2017-01-01

    The Langley mobile ozone lidar (LMOL) is a mobile ground-based ozone lidar system that consists of a pulsed UV laser producing two UV wavelengths of 286 and 291 nm with energy of approximately 0.2 mJ/pulse 0.2 mJ/pulse and repetition rate of 1 kHz. The 527 nm pump laser is also transmitted for aerosol measurements. The receiver consists of a 40 cm parabolic telescope, which is used for both backscattered analog and photon counting. The lidar is very compact and highly mobile. This demonstrates the utility of very small lidar systems eventually leading to space-based ozone lidars. The lidar has been validated by numerous ozonesonde launches and has provided ozone curtain profiles from ground to approximately 4 km in support of air quality field missions.

  6. Metal fractionation of atmospheric aerosols via sequential chemical extraction: a review

    Energy Technology Data Exchange (ETDEWEB)

    Smichowski, Patricia; Gomez, Dario [Unidad de Actividad Quimica, Comision Nacional de Energia Atomica, San Martin (Argentina); Polla, Griselda [Unidad de Actividad Fisica, Comision Nacional de Energia Atomica, San Martin (Argentina)

    2005-01-01

    This review surveys schemes used to sequentially chemically fractionate metals and metalloids present in airborne particulate matter. It focuses mainly on sequential chemical fractionation schemes published over the last 15 years. These schemes have been classified into five main categories: (1) based on Tessier's procedure, (2) based on Chester's procedure, (3) based on Zatka's procedure, (4) based on BCR procedure, and (5) other procedures. The operational characteristics as well as the state of the art in metal fractionation of airborne particulate matter, fly ashes and workroom aerosols, in terms of applications, optimizations and innovations, are also described. Many references to other works in this area are provided. (orig.)

  7. Atmospheric inversion of SO2 and primary aerosol emissions for the year 2010

    Directory of Open Access Journals (Sweden)

    N. Huneeus

    2013-07-01

    Full Text Available Natural and anthropogenic emissions of primary aerosols and sulphur dioxide (SO2 are estimated for the year 2010 by assimilating daily total and fine mode aerosol optical depth (AOD at 550 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS satellite instrument into a global aerosol model of intermediate complexity. The system adjusts monthly emission fluxes over a set of predefined regions tiling the globe. The resulting aerosol emissions improve the model performance, as measured from usual skill scores, both against the assimilated observations and a set of independent ground-based measurements. The estimated emission fluxes are 67 Tg S yr−1 for SO2, 12 Tg yr−1 for black carbon (BC, 87 Tg yr−1 for particulate organic matter (POM, 17 000 Tg yr−1 for sea salt (SS, estimated at 80 % relative humidity and 1206 Tg yr−1 for desert dust (DD. They represent a difference of +53, +73, +72, +1 and −8%, respectively, with respect to the first guess (FG values. Constant errors throughout the regions and the year were assigned to the a priori emissions. The analysis errors are reduced with respect to the a priori ones for all species and throughout the year, they vary between 3 and 18% for SO2, 1 and 130% for biomass burning, 21 and 90 % for fossil fuel, 1 and 200% for DD and 1 and 5% for SS. The maximum errors on the global-yearly scale for the estimated fluxes (considering temporal error dependence are 3% for SO2, 14% for BC, 11% for POM, 14% for DD and 2% for SS. These values represent a decrease as compared to the global-yearly errors from the FG of 7% for SO2, 40% for BC, 55% for POM, 81% for DD and 300% for SS. The largest error reduction, both monthly and yearly, is observed for SS and the smallest one for SO2. The sensitivity and robustness of the inversion system to the choice of the first guess emission inventory is investigated by using different combinations of inventories for industrial, fossil fuel and biomass burning

  8. Variability of atmospheric aerosols at urban, regional and continental backgrounds in the western mediterranean basin

    OpenAIRE

    Pérez Lozano, Noemí

    2010-01-01

    Descripció del recurs: el 14 de febrer de 2011 El estudio de los niveles y composición del material particulado atmosférico (PM) medido simultáneamente en diferentes ambientes a escala regional se llevó a cabo en la cuenca del Mediterráneo Occidental con el fin de entender las fuentes y patrones de transformación y transporte de aerosoles en esta zona. Para esto, la medida de niveles y caracterización química de PM10, PM2.5 y PM1 se llevó a cabo en tres estaciones de monitoreo: Montsec (MS...

  9. Critical assessment of the current state of scientific knowledge, terminology, and research needs concerning the role of organic aerosols in the atmosphere, climate, and global change

    Directory of Open Access Journals (Sweden)

    S. Fuzzi

    2006-01-01

    Full Text Available In spite of impressive advances in recent years, our present understanding of organic aerosol (OA composition, physical and chemical properties, sources and transformation characteristics is still rather limited, and their environmental effects remain highly uncertain. This paper discusses and prioritizes issues related to organic aerosols and their effects on atmospheric processes and climate, providing a basis for future activities in the field. Four main topical areas are addressed: i sources of OA; ii formation transformation and removal of OA; iii physical, chemical and mixing state of OA; iv atmospheric modelling of OA. Key questions and research priorities regarding these four areas are synthesized in this paper, and outstanding issues for future research are presented for each topical area. In addition, an effort is made to formulate a basic set of consistent and universally applicable terms and definitions for coherent description of atmospheric OA across different scales and disciplines.

  10. How much information do extinction and backscattering measurements contain about the chemical composition of atmospheric aerosol?

    Science.gov (United States)

    Kahnert, Michael; Andersson, Emma

    2017-03-01

    We theoretically and numerically investigate the problem of assimilating multiwavelength lidar observations of extinction and backscattering coefficients of aerosols into a chemical transport model. More specifically, we consider the inverse problem of determining the chemical composition of aerosols from these observations. The main questions are how much information the observations contain to determine the particles' chemical composition, and how one can optimize a chemical data assimilation system to make maximum use of the available information. We first quantify the information content of the measurements by computing the singular values of the scaled observation operator. From the singular values we can compute the number of signal degrees of freedom, Ns, and the reduction in Shannon entropy, H. As expected, the information content as expressed by either Ns or H grows as one increases the number of observational parameters and/or wavelengths. However, the information content is strongly sensitive to the observation error. The larger the observation error variance, the lower the growth rate of Ns or H with increasing number of observations. The right singular vectors of the scaled observation operator can be employed to transform the model variables into a new basis in which the components of the state vector can be partitioned into signal-related and noise-related components. We incorporate these results in a chemical data assimilation algorithm by introducing weak constraints that restrict the assimilation algorithm to acting on the signal-related model variables only. This ensures that the information contained in the measurements is fully exploited, but not overused. Numerical tests show that the constrained data assimilation algorithm provides a solution to the inverse problem that is considerably less noisy than the corresponding unconstrained algorithm. This suggests that the restriction of the algorithm to the signal-related model variables suppresses

  11. Changes in the lead content of atmospheric aerosols above the Eastern Channel between 1982/83 and 1994

    Energy Technology Data Exchange (ETDEWEB)

    Flament, Pascal; Bertho, Marie-Laure; Deboudt, Karine; Puskaric, Emile [Universitedu Littoral, Laboratoire de Chimie Analytique Appliquee al`Environnement, URA CNRS 1363, Wimereux (France)

    1996-11-01

    Lead concentrations in atmospheric particulate matter, along the southern coast of the Strait of Dover have been measured during two sampling campaigns, over a 10 year period. The results point out that lead concentrations have been decreased by a factor of two, from 1982/83 to 1994. This evolution is in good agreement with a general trend to the diminution of lead in atmospheric aerosols above the Eastern Channel and the Southern Bight of the North Sea. It appears that, from 1972 to 1994, lead concentrations have decreased by an order of magnitude, despite the uncertainty of the oldest values. As established in a similar coastal environment, this decrease in the lead concentrations can be explained by the reduction in the emissions of automotive lead. The evolution of the mass-size distribution is consistent with this last factor; assuming that automotive lead is essentially present in particles smaller than 0.33 {mu}m, the observed decrease of this granulometric class between 1983 and 1994 (7 ng/m{sup 3}) is close to the measured decrease in the lead concentrations (9 ng/m{sup 3}). A slight decrease (14%) of the related dry deposition flux has been calculated for the same period. But, if part of the fall-out due to particles larger than 1 {mu}m is approximately constant over the same period (about 430 g/km{sup 2} per year), the submicronic flux exhibits a decrease of 70%

  12. Competing effects of viscosity and surface-tension depression on the hygroscopicity and CCN activity of laboratory surrogates for oligomers in atmospheric aerosol

    Science.gov (United States)

    Hodas, N.; Zuend, A.; Shiraiwa, M.; Flagan, R. C.; Seinfeld, J.; Schilling, K.; Berkemeier, T.

    2015-12-01

    The presence of oligomers in biomass burning aerosol, as well as secondary organic aerosol derived from other sources, influences particle viscosity and can introduce kinetic limitations to water uptake. This, in turn, impacts aerosol optical properties and the efficiency with which these particles serve as cloud condensation nuclei (CCN). To explore the influence of organic-component viscosity on aerosol hygroscopicity, the water-uptake behavior of aerosol systems comprised of polyethylene glycol (PEG) and mixtures of PEG and ammonium sulfate (AS) was measured under sub- and supersaturated relative humidity (RH) conditions. Experiments were conducted with systems containing PEG with average molecular weights ranging from 200 to 10,000 g/mol, corresponding to a range in viscosity of 0.004 - 4.5 Pa s under dry conditions. While evidence suggests that viscous aerosol components can suppress water uptake at RH activity with increasing PEG molecular weight was observed. We attribute this to an increase in the efficiency with which PEG serves as a surfactant with increasing molecular weight. This effect is most pronounced for PEG-AS mixtures and, in fact, a modest increase in CCN activity is observed for the PEG 10,000-AS mixture as compared to pure AS, as evidenced by a 4% reduction in critical activation diameter. Experimental results are compared with calculations of hygroscopic growth at thermodynamic equilibrium using the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients model and the potential influence of kinetic limitations to observed water uptake is further explored with the Kinetic Multi-Layer Model of Gas-Particle Interactions. Results suggest the competing effects of organic-component viscosity and surface-tension depression may lead to RH-dependent differences in hygroscopicity for oligomers and other surface-active compounds present in atmospheric aerosols, for which PEG serves as a surrogate in these experiments.

  13. Radioactive isotopes in atmospheric aerosols over Russia and the Sea of Japan following nuclear accident at Fukushima Nr. 1 Daiichi Nuclear Power Station in March 2011.

    Science.gov (United States)

    Neroda, Andrey S; Mishukov, Vasily F; Goryachev, Vladimir A; Simonenkov, Denis V; Goncharova, Anna A

    2014-04-01

    Artificial radionuclides, such as iodine-131 ((131)I), cesium-134 ((134)Cs), and cesium-137 ((137)Cs), as well as natural isotopes of beryllium-7 ((7)Be) and potassium-40 ((40)K) have been registered in atmospheric aerosols over Vladivostok selected from 11 March to 17 June 2011. Additionally, (134)Cs and (137)Cs were detected in atmospheric aerosols over Tomsk selected from 16 March to 17 June 2011. Artificial radionuclides were also discovered in atmospheric wet depositions sampled in Vladivostok from 3 to 17 May 2011. Moreover, these radionuclides have been registered in atmospheric aerosols over the sea surface of the Sea of Japan selected from 3 to 31 May 2011 during an expedition of the "Nadezhda" sailing ship. From 18 March to 15 April, an increase in concentrations of atmospheric aerosols over Vladivostok from 108.8 to 321.5 μg/m(3) has been registered. It was accompanied by increased activity concentrations of (134)Cs, (137)Cs, and the (131)I. During the period from 18 March to 15 April, activity concentrations of (137)Cs and (134)Cs in atmospheric aerosols increased 100 times compared with the minimum detectable concentration (MDC) level and peaked in the weekly sample gathered from 8 to 15 April (145.0 and 105.3 μBq/m(3), respectively). Variability of concentrations of natural isotopes of (7)Be and (40)K was not greater than 1 order of magnitude throughout the sampling period. Maximal values of (137)Cs and (134)Cs concentrations (1,281.5 ± 141 and 384.4 ± 42.3 μBq/m(3), respectively) in Tomsk were reached in samples taken from 1 to 2 April. For the atmospheric aerosol samples from the Sea of Japan, the largest concentration of (131)I (392.3 ± 215.7 μBq/m(3)) was detected from 13 to 19 May, while all other samples had much lower concentration values. Synoptic analysis of back trajectories movement of air masses showed that the radioactive cloud came to Vladivostok from the regions of Siberia and northeastern part of China. Synoptic

  14. Program and Poster Abstracts from the Workshop on the Formation and Growth of Atmospheric Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    McMurry, Peter H. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Mechanical Engineering; Kulmala, Markku [Univ. of Helsinki (Finland). Dept. of Physics. Division of Atmospheric Sciences

    2006-09-09

    DOE provided $11,000 to sponsor the Workshop on New Particle Formation in the Atmosphere, which was held at The Riverwood Inn and Conference Center near Minneapolis, MN from September 7 to 9, 2006. Recent work has shown that new particle formation is an important atmospheric process that must be better understood due to its impact on cloud cover and the Earth's radiation balance. The conference was an informal gathering of atmospheric and basic scientists with expertise pertinent to this topic. The workshop included discussions of: • atmospheric modeling; • computational chemistry pertinent to clustering; • ions and ion induced nucleation; • basic laboratory and theoretical studies of nucleation; • studies on neutral molecular clusters; • interactions of organic compounds and sulfuric acid; • composition of freshly nucleated particles. Fifty six scientists attended the conference. They included 27 senior scientists, 9 younger independent scientists (assistant professor or young associate professor level), 7 postdocs, 13 graduate students, 10 women, 35 North Americans (34 from the U.S.), 1 Asian, and 20 Europeans. This was an excellent informal workshop on an important topic. An effort was made to include individuals from communities that do not regularly interact. A number of participants have provided informal feedback indicating that the workshop led to research ideas and possible future collaborations. This document includes abstracts from this workshop.

  15. Long-Term, High-Resolution Survey of Atmospheric Aerosols over Egypt with NASA’s MODIS Data

    Directory of Open Access Journals (Sweden)

    Mohammed Shokr

    2017-10-01

    Full Text Available A decadal survey of atmospheric aerosols over Egypt and selected cities and regions is presented using daily aerosol optical depth (AOD data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS at 550 nm wavelength onboard the Aqua satellite. We explore the AOD spatio-temporal variations over Egypt during a 12-year record (2003 to 2014 using the MODIS high-resolution (10 km Level 2 data product. Five cities and two geographic regions that feature different landscape and human activities were selected for detailed analysis. For most of the examined areas, AOD is found to be most frequent in the 0.2–0.3 range, and the highest mean AOD was found to be over Cairo, Alexandria, and the Nile Delta region. Severe events are identified based on AOD higher than a selected threshold. Most of these events are engendered by sand and dust storms that originate from the Western Desert during January–April. Spatial analysis indicates that they cover the Nile Delta region, including cities of Cairo and Alexandria, on the same day. Examination of the spatial gradient of AOD along the four cardinal directions originating from the city’s center reveals seasonally dependent gradients in some cases. The gradients have been linked to locations of industrial activity. No trend of AOD has been observed in the studied areas during the study period, though data from Cairo and Asyut reveal a slight linear increase of AOD. Considering Cairo is commonly perceived as a city of poor air quality, the results show that local events are fairly constrained. The study highlights spatial and seasonal distributions of AOD and links them to geographic and climatic conditions across the country.

  16. Changes in concentration, composition and source contribution of atmospheric organic aerosols by shifting coal to natural gas in Urumqi

    Science.gov (United States)

    Ren, Yanqin; Wang, Gehui; Wu, Can; Wang, Jiayuan; Li, Jianjun; Zhang, Lu; Han, Yanni; Liu, Lang; Cao, Cong; Cao, Junji; He, Qing; Liu, Xinchun

    2017-01-01

    Size-segregated aerosols were collected in Urumqi, a megacity in northwest China, during two heating seasons, i.e., before (heating season І: January-March 2012) and after (heating season II: January-March 2014) the project "shifting coal to natural gas", and determined for n-alkanes, PAHs and oxygenated PAHs to investigate the impact of replacement of coal by natural gas on organic aerosols in the urban atmosphere. Our results showed that compared to those in heating season I concentrations of n-alkanes, PAHs and OPAHs decreased by 74%, 74% and 82% in heating season II, respectively. Source apportionment analysis suggested that coal combustion, traffic emission and biomass burning are the major sources of the determined organics during the heating seasons in Urumqi. Traffic emission is the main source for n-alkanes in the city. Coal combustion is the dominant source of PAHs and OPAHs in heating season І, but traffic emission becomes their major source in heating season ІI. Relative contributions of coal combustion to n-alkanes, PAHs and OPAHs in Urumqi decreased from 21 to 75% in heating season I to 4.0-21% in heating season II due to the replacement of coal with natural gas for house heating. Health risk assessment further indicated that compared with that in heating season I the number of lung cancer related to PAHs exposure in Urumqi decreased by 73% during heating season II due to the project implementation. Our results suggest that replacing coal by clean energy sources for house heating will significantly mitigate air pollution and improve human health in China.

  17. Light Absorption of Black Carbon Aerosol and Its Radiative Forcing Effect in an Megacity Atmosphere in South China

    Science.gov (United States)

    Lan, Zijuan

    2013-04-01

    The effects of black carbon (BC) aerosol on climate warming have been the study focus in the recent decade, the regional effect of BC light absorption is more significant. The reduction of BC is now expected to have significant near-term climate change mitigation. Mass absorption efficient (MAE) was one of the important optical properties of BC aerosol for evaluating the BC on its radiative forcing effect, while BC mixing state is one main influencing factor for MAE. Models have estimated that BC radiative forcing can be increased by a factor of ~2 for internally versus externally mixed BC. On the other hand, some organic carbon had been found to significantly absorb light at UV or shorter wavelengths in the most recent studies, with strong spectral dependence. But large uncertainties still remain in determining the positive forcing effect of BC on global clime change due to the technical limitations. In this study, advanced instrumentation (a three-wavelength photoacoustic soot spectrometer (PASS-3) and a single particle soot photometer (SP2)) were used to measure black carbon aerosol and analyze its optical properties in a megacity in South China, Shenzhen, during the summer of 2011. It is in the southeast corner of the Pearl River Delta (PRD) region, neighboring Hong Kong to the south. During the campaign, the average BC mass concentration was 4.0±3.1 μg m-3, accounting for about 11% of PM2.5 mass concentration, which mainly came from fossil fuel combustion rather than biomass burning. The MAE of BC ranged from 5.0 to 8.5 m2 g-1, with an average value of 6.5±0.5 m2 g-1. The percentage of internally mixed BC was averagely 24.3±7.9% and positively correlated with the MAE. It is estimated that the internally mixed BC amplified MAE by about 7% during the campaign, suggesting that the BC absorption enhancement due to internal mixing in the real atmosphere is relatively low in comparison with the predictions by theoretical models, which stands in accordance with

  18. Secondary organic aerosol from atmospheric photooxidation of indole

    Directory of Open Access Journals (Sweden)

    J. Montoya-Aguilera

    2017-09-01

    Full Text Available Indole is a heterocyclic compound emitted by various plant species under stressed conditions or during flowering events. The formation, optical properties, and chemical composition of secondary organic aerosol (SOA formed by low-NOx photooxidation of indole were investigated. The SOA yield (1. 3 ± 0. 3 was estimated from measuring the particle mass concentration with a scanning mobility particle sizer (SMPS and correcting it for wall loss effects. The high value of the SOA mass yield suggests that most oxidized indole products eventually end up in the particle phase. The SOA particles were collected on filters and analysed offline with UV–vis spectrophotometry to measure the mass absorption coefficient (MAC of the bulk sample. The samples were visibly brown and had MAC values of  ∼ 2 m2 g−1 at λ = 300 nm and  ∼ 0. 5 m2 g−1 at λ = 400 nm, comparable to strongly absorbing brown carbon emitted from biomass burning. The chemical composition of SOA was examined with several mass spectrometry methods. Direct analysis in real-time mass spectrometry (DART-MS and nanospray desorption electrospray high-resolution mass spectrometry (nano-DESI-HRMS were both used to provide information about the overall distribution of SOA compounds. High-performance liquid chromatography, coupled to photodiode array spectrophotometry and high-resolution mass spectrometry (HPLC-PDA-HRMS, was used to identify chromophoric compounds that are responsible for the brown colour of SOA. Indole derivatives, such as tryptanthrin, indirubin, indigo dye, and indoxyl red, were found to contribute significantly to the visible absorption spectrum of indole SOA. The potential effect of indole SOA on air quality was explored with an airshed model, which found elevated concentrations of indole SOA during the afternoon hours contributing considerably to the total organic aerosol under selected scenarios. Because of its high MAC values

  19. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    Aerosols are important climactically. Their specific emissions are key to reducing the uncertainty in global climate models. Marine aerosols make up the largest source of primary aerosols to the Earth's atmosphere. Uncertainty in marine aerosol mass and number flux lies in separating primary emis...... with decreasing temperature. Unique surface images of bubble size distributions allow the investigation of temperature, bubble size, and particle production......Aerosols are important climactically. Their specific emissions are key to reducing the uncertainty in global climate models. Marine aerosols make up the largest source of primary aerosols to the Earth's atmosphere. Uncertainty in marine aerosol mass and number flux lies in separating primary...... entrainment may account for the large discrepancy in energy input for the two systems. In the third study, the temperature dependence of sea spray aerosol production is probed with the use of a highly stable temperature controlled plunging jet. Similar to previous studies, particle production increases...

  20. Contribution of carbonyl photochemistry to aging of atmospheric secondary organic aerosol.

    Science.gov (United States)

    Mang, Stephen A; Henricksen, Dana K; Bateman, Adam P; Andersen, Mads P Sulbaek; Blake, Donald R; Nizkorodov, Sergey A

    2008-09-11

    The photodegradation of secondary organic aerosol (SOA) material by actinic UV radiation was investigated. SOA was generated via the dark reaction of ozone and d-limonene, collected onto quartz-fiber filters, and exposed to wavelength-tunable radiation. Photochemical production of CO was monitored in situ by infrared cavity ring-down spectroscopy. A number of additional gas-phase products of SOA photodegradation were observed by gas chromatography, including methane, ethene, acetaldehyde, acetone, methanol, and 1-butene. The absorption spectrum of SOA material collected onto CaF2 windows was measured and compared with the photolysis action spectrum for the release of CO, a marker for Norrish type-I photocleavage of carbonyls. Both spectra had a band at approximately 300 nm corresponding to the overlapping n --> pi* transitions in nonconjugated carbonyls. The effective extinction coefficient of freshly prepared SOA was estimated to be on the order of 15 L mol(-1) cm(-1) at 300 nm, implying one carbonyl group in every SOA constituent. The absorption by the SOA material slowly increased in the visible and near-UV during storage of SOA in open air in the dark, presumably as a result of condensation reactions that increased the degree of conjugation in the SOA constituents. These observations suggest that photolysis of carbonyl functional groups represents a significant sink for monoterpene SOA compounds in the troposphere, with an estimated lifetime of several hours over the continental United States.

  1. Temporal Variation of Atmospheric Aerosol Particulate Matters and Heavy Metal Concentrations in Dhaka, Bangladesh

    Directory of Open Access Journals (Sweden)

    Tanzir Al Mahmud, , and *

    2008-06-01

    Full Text Available Aerosol particulate matters and heavy metal concentrations were measured for the period of August and September 2005 in Dhaka a Southeast Asian Mega City. Particulate matters (PM of different size fractions (TSP, PM10 and PM2.5 were collected on the micro fiber filters by placing the PM sampler on the roof of the Mohkarram Hossain Khundhkar Biggan Bhaban at the Department of Chemistry, University of Dhaka, Bangladesh. The overall average concentrations of TSP, PM10 and PM2.5 were 68, 43 and 35 µg m-3, respectively. About 82% particles were from fine fraction (PM2.5 and 18% were from coarse fraction (PM10-2.5, which indicates mechanical processes are one of the main sources for the particulate matters in Dhaka. Heavy metals (lead, copper, zinc, and iron concentrations were determined by using atomic absorption spectrophotometer (AAS for the size fraction of PM10 with highest concentrations recorded for iron (2360 ng m-3 and lowest for copper (28 ng m-3. The average concentration for lead (96 ng m-3 was lower than the WHO guideline value and also lower than the previous measurements in Dhaka. The lower concentration of lead was found presumably due to the official ban of leaded gasoline in Dhaka, Bangladesh.

  2. Dust signatures observed in atmospheric aerosols and related to radiative transfer algorithms

    OpenAIRE

    Boccone, Marzia

    2012-01-01

    The Natural Sources of pollutants, such as Sahara desert dust outbreaks or ashes from vulcanoes, in many cases, could grow the bad air quality forecast and PM limits values measured could exeed the European Law recomendations, in that case the country have to pay to the Community if an evidence of that is a Natural Pollutant is not brought to the European Court. The goal to control air quality could be reached studying the pollution sources, the dispersion with atmospheric model, the chemical...

  3. Aerosol scattering and absorption during the EUCAARI-LONGREX flights of the Facility for Airborne Atmospheric Measurements (FAAM BAe-146: can measurements and models agree?

    Directory of Open Access Journals (Sweden)

    E. J. Highwood

    2012-08-01

    Full Text Available Scattering and absorption by aerosol in anthropogenically perturbed air masses over Europe has been measured using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA operated by the Facility for Airborne Atmospheric Measurements (FAAM on 14 flights during the EUCAARI-LONGREX campaign in May 2008. The geographical and temporal variations of the derived shortwave optical properties of aerosol are presented. Values of single scattering albedo of dry aerosol at 550 nm varied considerably from 0.86 to near unity, with a campaign average of 0.93 ± 0.03. Dry aerosol optical depths ranged from 0.030 ± 0.009 to 0.24 ± 0.07. An optical properties closure study comparing calculations from composition data and Mie scattering code with the measured properties is presented. Agreement to within measurement uncertainties of 30% can be achieved for both scattering and absorption, but the latter is shown to be sensitive to the refractive indices chosen for organic aerosols, and to a lesser extent black carbon, as well as being highly dependent on the accuracy of the absorption measurements. Agreement with the measured absorption can be achieved either if organic carbon is assumed to be weakly absorbing, or if the organic aerosol is purely scattering and the absorption measurement is an overestimate due to the presence of large amounts of organic carbon. Refractive indices could not be inferred conclusively due to this uncertainty, despite the enhancement in methodology compared to previous studies that derived from the use of the black carbon measurements. Hygroscopic growth curves derived from the wet nephelometer indicate moderate water uptake by the aerosol with a campaign mean f(RH value (ratio in scattering of 1.5 (range from 1.23 to 1.63 at 80% relative humidity. This value is qualitatively consistent with the major chemical components of the aerosol measured by the aerosol mass spectrometer, which are primarily

  4. Describing the direct and indirect radiative effects of atmospheric aerosols over Europe by using coupled meteorology-chemistry simulations: a contribution from the AQMEII-Phase II exercise

    Science.gov (United States)

    Jimenez-Guerrero, Pedro; Balzarini, Alessandra; Baró, Rocío; Curci, Gabriele; Forkel, Renate; Hirtl, Marcus; Honzak, Luka; Langer, Matthias; Pérez, Juan L.; Pirovano, Guido; San José, Roberto; Tuccella, Paolo; Werhahn, Johannes; Zabkar, Rahela

    2014-05-01

    The study of the response of the aerosol levels in the atmosphere to a changing climate and how this affects the radiative budget of the Earth (direct, semi-direct and indirect effects) is an essential topic to build confidence on climate science, since these feedbacks involve the largest uncertainties nowadays. Air quality-climate interactions (AQCI) are, therefore, a key, but uncertain contributor to the anthropogenic forcing that remains poorly understood. To build confidence in the AQCI studies, regional-scale integrated meteorology-atmospheric chemistry models (i.e., models with on-line chemistry) that include detailed treatment of aerosol life cycle and aerosol impacts on radiation (direct effects) and clouds (indirect effects) are in demand. In this context, the main objective of this contribution is the study and definition of the uncertainties in the climate-chemistry-aerosol-cloud-radiation system associated to the direct radiative forcing and the indirect effect caused by aerosols over Europe, using an ensemble of fully-coupled meteorology-chemistry model simulations with the WRF-Chem model run under the umbrella of AQMEII-Phase 2 international initiative. Simulations were performed for Europe for the entire year 2010. According to the common simulation strategy, the year was simulated as a sequence of 2-day time slices. For better comparability, the seven groups applied the same grid spacing of 23 km and shared common processing of initial and boundary conditions as well as anthropogenic and fire emissions. With exception of a simulation with different cloud microphysics, identical physics options were chosen while the chemistry options were varied. Two model set-ups will be considered here: one sub-ensemble of simulations not taking into account any aerosol feedbacks (the baseline case) and another sub-ensemble of simulations which differs from the former by the inclusion of aerosol-radiation feedback. The existing differences for meteorological

  5. Coagulation effect on the activity size distributions of long lived radon progeny aerosols and its application to atmospheric residence time estimation techniques.

    Science.gov (United States)

    Anand, S; Mayya, Y S

    2015-03-01

    The long lived naturally occurring radon progeny species in the atmosphere, namely (210)Pb, (210)Bi and (210)Po, have been used as important tracers for understanding the atmospheric mixing processes and estimating aerosol residence times. Several observations in the past have shown that the activity size distribution of these species peaks at larger particle sizes as compared to the short lived radon progeny species - an effect that has been attributed to the process of coagulation of the background aerosols to which they are attached. To address this issue, a mathematical equation is derived for the activity-size distribution of tracer species by formulating a generalized distribution function for the number of tracer atoms present in coagulating background particles in the presence of radioactive decay and removal. A set of these equations is numerically solved for the progeny chain using Fuchs coagulation kernel combined with a realistic steady-state aerosol size spectrum that includes nucleation, accumulation and coarse mode components. The important findings are: (i) larger shifts in the modal sizes of (210)Pb and (210)Po at higher aerosol concentrations such as that found in certain Asian urban regions (ii) enrichment of tracer specific activity on particles as compared to that predicted by pure attachment laws (iii) sharp decline of daughter-to-parent activity ratios for decreasing particle sizes. The implication of the results to size-fractionated residence time estimation techniques is highlighted. A coagulation corrected graphical approach is presented for estimating the residence times from the size-segregated activity ratios of (210)Bi and (210)Po with respect to (210)Pb. The discrepancy between the residence times predicted by conventional formula and the coagulation corrected approach for specified activity ratios increases at higher atmospheric aerosol number concentrations (>10(10) #/m(3)) for smaller sizes (<1 μm). The results are further

  6. Chemical speciation of vanadium in particulate matter emitted from diesel vehicles and urban atmospheric aerosols.

    Science.gov (United States)

    Shafer, Martin M; Toner, Brandy M; Overdier, Joel T; Schauer, James J; Fakra, Sirine C; Hu, Shaohua; Herner, Jorn D; Ayala, Alberto

    2012-01-03

    We report on the development and application of an integrated set of analytical tools that enable accurate measurement of total, extractable, and, importantly, the oxidation state of vanadium in sub-milligram masses of environmental aerosols and solids. Through rigorous control of blanks, application of magnetic-sector-ICPMS, and miniaturization of the extraction/separation methods we have substantially improved upon published quantification limits. The study focused on the application of these methods to particulate matter (PM) emissions from diesel vehicles, both in baseline configuration without after-treatment and also equipped with advanced PM and NO(x) emission controls. Particle size-resolved vanadium speciation data were obtained from dynamometer samples containing total vanadium pools of only 0.2-2 ng and provide some of the first measurements of the oxidation state of vanadium in diesel vehicle PM emissions. The emission rates and the measured fraction of V(V) in PM from diesel engines running without exhaust after-treatment were both low (2-3 ng/mile and 13-16%, respectively). The V(IV) species was measured as the dominant vanadium species in diesel PM emissions. A significantly greater fraction of V(V) (76%) was measured in PM from the engine fitted with a prototype vanadium-based selective catalytic reductors (V-SCR) retrofit. The emission rate of V(V) determined for the V-SCR equipped vehicle (103 ng/mile) was 40-fold greater than that from the baseline vehicle. A clear contrast between the PM size-distributions of V(V) and V(IV) emissions was apparent, with the V(V) distribution characterized by a major single mode in the ultrafine (vanadium-containing fine-particle PM from the V-SCR identified V(2)O(5) as the dominant vanadium species.

  7. Parameterization of aerosol scavenging due to atmospheric ionization under varying relative humidity

    Science.gov (United States)

    Zhang, Liang; Tinsley, Brian A.

    2017-05-01

    Simulations and parameterizations of the modulation of aerosol scavenging by electric charges on particles and droplets for different relative humidities have been made for 3 μm radii droplets and a wide range of particle radii. For droplets and particles with opposite-sign charges, the attractive Coulomb force increases the collision rate coefficients above values due to other forces. With same-sign charges, the repulsive Coulomb force decreases the rate coefficients, and the short-range attractive image forces become important. The phoretic forces are attractive for relative humidity less than 100% and repulsive for relative humidity greater than 100% and have increasing overall effect for particle radii up to about 1 μm. There is an analytic solution for rate coefficients if only inverse square forces are present, but due to the presence of image forces, and for larger particles the intercept, weight, and the flow around the particle affecting the droplet trajectory, the simulated results usually depart far from the analytic solution. We give simple empirical parameterization formulas for some cases and more complex parameterizations for more exact fits to the simulated results. The results can be used in cloud models with growing droplets, as in updrafts, as well as with evaporating droplets in downdrafts. There is considered to be little scavenging of uncharged ice-forming nuclei in updrafts, but with charged ice-forming nuclei it is possible for scavenging in updrafts in cold clouds to produce contact ice nucleation. Scavenging in updrafts below the freezing level produces immersion nuclei that promote enhanced freezing as droplets rise above it.

  8. Atmospheric Aerosol Source-Receptor Relationships: The Role of Coal-Fired Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

    2005-12-01

    This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2005 through August 2005. Significant progress was made this project period on the source characterization, source apportionment, and deterministic modeling activities. This report highlights new data on road dust, vegetative detritus and motor vehicle emissions. For example, the results show significant differences in the composition in urban and rural road dust. A comparison of the organic of the fine particulate matter in the tunnel with the ambient provides clear evidence of the significant contribution of vehicle emissions to ambient PM. The source profiles developed from this work are being used by the source-receptor modeling activities. The report presents results on the spatial distribution of PMF-factors. The results can be grouped into three different categories: regional sources, local sources, or potentially both regional and local sources. Examples of the regional sources are the sulfate and selenium PMF-factors which most likely-represent coal fired power plants. Examples of local sources are the specialty steel and lead factors. There is reasonable correspondence between these apportionments and data from the EPA TRI and AIRS emission inventories. Detailed comparisons between PMCAMx predictions and measurements by the STN and IMPROVE measurements in the Eastern US are presented. Comparisons were made for the major aerosol components and PM{sub 2.5} mass in July 2001, October 2001, January 2002, and April 2002. The results are encouraging with average fraction biases for most species less than 0.25. The improvement of the model performance during the last two years was mainly due to the comparison of the model predictions with the continuous measurements in the Pittsburgh Supersite. Major improvements have included the descriptions: of ammonia emissions (CMU inventory), night time nitrate chemistry, EC emissions and their diurnal

  9. Fossil Fuel Combustion-Related Emissions Dominate Atmospheric Ammonia Sources during Severe Haze Episodes: Evidence from 15N-Stable Isotope in Size-Resolved Aerosol Ammonium

    Science.gov (United States)

    Pan, Y.; Tian, S.; Liu, D.; Fang, Y.; Zhu, X.; Zhang, Q.; Zheng, B.; Michalski, G. M.; Wang, Y.

    2016-12-01

    The reduction of ammonia (NH3) emissions is urgently needed due to its major contributions to nitrogen deposition and particle pollution. However, the relative contributions of individual NH3 sources are unclear, and debate remains over whether agricultural emissions dominate atmospheric NH3 in urban areas. Based on the chemical and isotopic measurements of size-resolved aerosols in urban Beijing, China, we find that the natural abundance of 15N (expressed using δ15N values) of ammonium (NH4+) in fine particles varies with the development of haze episodes, ranging from -37.1‰ to -21.7‰ during clean/dusty days (relative humidity: ˜ 40%), to -13.1‰ to +5.8‰ during hazy days (relative humidity: 70-90%). After factoring the isotope exchange between NH3 gas and aerosol NH4+, the δ15N value of the initial NH3 during hazy days is found to be -14.5‰ to -1.6‰, which indicates fossil fuel-based emissions. These emissions contribute 90% of the total NH3 during hazy days in urban Beijing. This work demonstrates the analysis of δ15N values of aerosol NH4+ to be a promising new tool for partitioning atmospheric NH3 sources, providing policy makers with insights into NH3 emissions and secondary aerosols for regulation in urban environments. This work also shed lights on the sources of nitrogen deposition in downwind ecosystems.

  10. Combining external and internal mixing representation of atmospheric aerosol for optical properties calculations: focus on absorption properties over Europe and North America using AERONET observations and AQMEII simulations

    Science.gov (United States)

    Curci, Gabriele

    2017-04-01

    The calculation of optical properties from knowledge of the composition and abundance of atmospheric aerosol implies a certain number of assumptions. First and if not known or explicitly simulated, a size distribution must be assigned to each aerosol component (e.g. sulfate-like inorganic ions, organic and back carbon, soil dust, sea salt). Second, physical-chemical properties such as the shape, density, complex refractive index, and hygroscopic factors must be associated to each aerosol species. Third, a representation of how the aerosol species combine together must be made: among those, the most popular are the assumptions of external mixing, in which each particle is assumed to be formed of a single compound and the optical properties may be calculated separately for each species, or of internal core-shell arrangement, in which each particle consists of a water-insoluble core coated with a water-soluble shell and that requires more elaborate calculations for optical properties. Previous work found that the assumption on the mixing state (external or core-shell internal) is the one that introduces the highest uncertainty, quantified in about 30% uncertainty on the calculation of monthly mean aerosol optical depth (AOD) and single-scattering albedo (SSA). The external mixing assumption is generally more reasonable for freshly emitted aerosol, while the internal mixing case is associated with aged aerosol that had the time to form the coating around the core. Both approximations are thus regarded as valid, but in general a combination of the two mixing states may be expected in a given air mass. In this work, we test a simple empirical parameterization of the fraction of internally mixed particles (F_in) in a generic air mass. The F_in fraction is calculated in two alternative ways, one exploiting the NOz to NOx ratio (proxy of the photochemical aging), and the other using the relative abundance of black carbon with respect to other aerosol components (proxy of

  11. Estimation of aerosol water and chemical composition from AERONET Sun-sky radiometer measurements at Cabauw, the Netherlands

    NARCIS (Netherlands)

    Van Beelen, A. J.; Roelofs, G. J H; Hasekamp, O. P.; Henzing, J. S.; Röckmann, T.

    2014-01-01

    Remote sensing of aerosols provides important information on atmospheric aerosol abundance. However, due to the hygroscopic nature of aerosol particles observed aerosol optical properties are influenced by atmospheric humidity, and the measurements do not unambiguously characterize the aerosol dry

  12. Molecular dynamics simulation of the local concentration and structure in multicomponent aerosol nanoparticles under atmospheric conditions.

    Science.gov (United States)

    Karadima, Katerina S; Mavrantzas, Vlasis G; Pandis, Spyros N

    2017-06-28

    Molecular dynamics (MD) simulations were employed to investigate the local structure and local concentration in atmospheric nanoparticles consisting of an organic compound (cis-pinonic acid or n-C30H62), sulfate and ammonium ions, and water. Simulations in the isothermal-isobaric (NPT) statistical ensemble under atmospheric conditions with a prespecified number of molecules of the abovementioned compounds led to the formation of a nanoparticle. Calculations of the density profiles of all the chemical species in the nanoparticle, the corresponding radial pair distribution functions, and their mobility inside the nanoparticle revealed strong interactions developing between sulfate and ammonium ions. However, sulfate and ammonium ions prefer to populate the central part of the nanoparticle under the simulated conditions, whereas organic molecules like to reside at its outer surface. Sulfate and ammonium ions were practically immobile; in contrast, the organic molecules exhibited appreciable mobility at the outer surface of the nanoparticle. When the organic compound was a normal alkane (e.g. n-C30H62), a well-organized (crystalline-like) phase was rapidly formed at the free surface of the nanoparticle and remained separate from the rest of the species.

  13. Analytical Models of Exoplanetary Atmospheres. IV. Improved Two-stream Radiative Transfer for the Treatment of Aerosols

    Science.gov (United States)

    Heng, Kevin; Kitzmann, Daniel

    2017-10-01

    We present a novel generalization of the two-stream method of radiative transfer, which allows for the accurate treatment of radiative transfer in the presence of strong infrared scattering by aerosols. We prove that this generalization involves only a simple modification of the coupling coefficients and transmission functions in the hemispheric two-stream method. This modification originates from allowing the ratio of the first Eddington coefficients to depart from unity. At the heart of the method is the fact that this ratio may be computed once and for all over the entire range of values of the single-scattering albedo and scattering asymmetry factor. We benchmark our improved two-stream method by calculating the fraction of flux reflected by a single atmospheric layer (the reflectivity) and comparing these calculations to those performed using a 32-stream discrete-ordinates method. We further compare our improved two-stream method to the two-stream source function (16 streams) and delta-Eddington methods, demonstrating that it is often more accurate at the order-of-magnitude level. Finally, we illustrate its accuracy using a toy model of the early Martian atmosphere hosting a cloud layer composed of carbon dioxide ice particles. The simplicity of implementation and accuracy of our improved two-stream method renders it suitable for implementation in three-dimensional general circulation models. In other words, our improved two-stream method has the ease of implementation of a standard two-stream method, but the accuracy of a 32-stream method.

  14. The importance of aerosol mixing state and size-resolved composition on CCN concentration and the variation of the importance with atmospheric aging of aerosols

    Directory of Open Access Journals (Sweden)

    J. Wang

    2010-08-01

    Full Text Available Aerosol microphysics, chemical composition, and CCN concentrations were measured at the T0 urban supersite in Mexico City during Megacity Initiative: Local and Global Research Observations (MILAGRO in March 2006. The aerosol size distribution and composition often showed strong diurnal variation associated with traffic emissions and aging of aerosols through coagulation and local photochemical production of secondary aerosol species. CCN concentrations (NCCN are derived using Köhler theory from the measured aerosol size distribution and various simplified aerosol mixing state and chemical composition, and are compared to concurrent measurements at five supersaturations ranging from 0.11% to 0.35%. The influence of assumed mixing state on calculated NCCN is examined using both aerosols observed during MILAGRO and representative aerosol types. The results indicate that while ambient aerosols often consist of particles with a wide range of compositions at a given size, NCCN may be derived within ~20% assuming an internal mixture (i.e., particles at a given size are mixtures of all participating species, and have the identical composition if great majority of particles has an overall κ (hygroscopicity parameter value greater than 0.1. For a non-hygroscopic particle with a diameter of 100 nm, a 3 nm coating of sulfate or nitrate is sufficient to increase its κ from 0 to 0.1. The measurements during MILAGRO suggest that the mixing of non-hygroscopic primary organic aerosol (POA and black carbon (BC particles with photochemically produced hygroscopic species and thereby the increase of their κ to 0.1 take place in a few hours during daytime. This rapid process suggests that during daytime, a few tens of kilometers away for POA and BC sources, NCCN may be derived with sufficient accuracy by assuming an internal mixture, and using bulk chemical composition. The rapid mixing also

  15. The importance of aerosol mixing state and size-resolved composition on CCN concentration and the variation of the importance with atmospheric aging of aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Cubison, M. J.; Aiken, A. C.; Jimenez, J. L.; Collins, D. R.

    2010-05-01

    Aerosol microphysics, chemical composition, and CCN concentrations were measured at the T0 urban supersite in Mexico City during Megacity Initiative: Local and Global Research Observations (MILAGRO) in March 2006. The aerosol size distribution and composition often showed strong diurnal variation associated with traffic emissions and aging of aerosols through coagulation and local photochemical production of secondary aerosol species. CCN concentrations (N{sub CCN}) are derived using Kohler theory from the measured aerosol size distribution and various simplified aerosol mixing state and chemical composition, and are compared to concurrent measurements at five supersaturations ranging from 0.11% to 0.35%. The influence of assumed mixing state on calculated N{sub CCN} is examined using both aerosols observed during MILAGRO and representative aerosol types. The results indicate that while ambient aerosols often consist of particles with a wide range of compositions at a given size, N{sub CCN} may be derived within {approx}20% assuming an internal mixture (i.e., particles at a given size are mixtures of all participating species, and have the identical composition) if great majority of particles has an overall {kappa} (hygroscopicity parameter) value greater than 0.1. For a non-hygroscopic particle with a diameter of 100 nm, a 3 nm coating of sulfate or nitrate is sufficient to increase its {kappa} from 0 to 0.1. The measurements during MILAGRO suggest that the mixing of non-hygroscopic primary organic aerosol (POA) and black carbon (BC) particles with photochemically produced hygroscopic species and thereby the increase of their {kappa} to 0.1 take place in a few hours during daytime. This rapid process suggests that during daytime, a few tens of kilometers away for POA and BC sources, N{sub CCN} may be derived with sufficient accuracy by assuming an internal mixture, and using bulk chemical composition. The rapid mixing also indicates that, at least for very active

  16. PM source apportionment and trace metallic aerosol affinities during atmospheric pollution episodes: a case study from Puertollano, Spain.

    Science.gov (United States)

    Moreno, Teresa; Querol, Xavier; Alastuey, Andrés; García do Santos, Saúl; Fernández Patier, Rosalia; Artiñano, Begoña; Gibbons, Wes

    2006-10-01

    Source apportionment study was performed, applying principal component analysis to the results of 221 chemical analyses of PM10 and PM2.5 samples collected daily from the industrial (but low traffic) Spanish town of Puertollano over a 14-month period during 2004-2005. Results reveal compositional variations attributable to different mixtures of natural and anthropogenic materials, mainly soil and rock dust (crustal), marine salt (only in PM10), petrochemical refinery emissions, and particles attributed to the combustion of local coal, which is unusually rich in Pb and Sb. During the study period there were 34 pollution episodes when PM10 exceeded 50 tg m(-3), mostly due to winter air temperature inversions, regional atmospheric stagnation, or African dust incursions (North African, NAF days: usually in summer). Whereas the crustal component during NAF episodes averaged 52% with a PM2.5/PM10 ratio of 0.54, this dropped to 29% and a PM2.5/PM10 of 0.67 during non-NAF days when anthropogenic materials predominated. Abnormally enhanced concentrations of pathfinder metallic trace elements provide additional evidence for source apportionment: thus aerosols with raised levels of Pb and Sb are associated with local coal combustion, Ni and V can be linked to petrochemical PM emissions, and Ti, Mn, Rb, and Ce are particularly characteristic of crustal dust incursions.

  17. Sources identification of the atmospheric aerosol at urban and suburban sites in Indonesia by positive matrix factorization.

    Science.gov (United States)

    Santoso, Muhayatun; Hopke, Philip K; Hidayat, Achmad; Diah Dwiana L

    2008-07-01

    Samples of fine and coarse fractions of airborne particulate matter were collected in Indonesia (west central Java) at an urban site in Bandung and in suburban Lembang from January 2002 to December 2004. The samples were collected using a Gent stacked filter sampler in two size fractions of Stain Reflectometer. The data sets were then analyzed using positive matrix factorization to identify the possible sources of fine and coarse atmospheric aerosols in both areas. The best solutions were found to be seven factors and five factors for elemental compositions of fine and coarse particulate matter in the urban area of Bandung and six factors and five factors for elemental compositions of fine and coarse particulate matter in the suburban area of Lembang, respectively. The sources are soil dust, motor vehicles, biomass burning, sea salt, and road dust. The PMF results showed that more than 50% of the PM2.5-10 mass at both sites comes from soil dust and road dust. The biomass burning factor contributes about 40% of the PM2.5 mass in case of suburban Lembang and about 20% in urban Bandung.

  18. Impact of Manaus City on the Amazon Green Ocean atmosphere: ozone production, precursor sensitivity and aerosol load

    Directory of Open Access Journals (Sweden)

    U. Kuhn

    2010-10-01

    Full Text Available As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001 field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry season transition period in July 2001. During the flights, we performed vertical stacks of crosswind transects in the urban outflow downwind of Manaus City, measuring a comprehensive set of trace constituents including O3, NO, NO2, CO, VOC, CO2, and H2O. Aerosol loads were characterized by concentrations of total aerosol number (CN and cloud condensation nuclei (CCN, and by light scattering properties. Measurements over pristine rainforest areas during the campaign showed low levels of pollution from biomass burning or industrial emissions, representative of wet season background conditions. The urban plume of Manaus City was found to be joined by plumes from power plants south of the city, all showing evidence of very strong photochemical ozone formation. One episode is discussed in detail, where a threefold increase in ozone mixing ratios within the atmospheric boundary layer occurred within a 100 km travel distance downwind of Manaus. Observation-based estimates of the ozone production rates in the plume reached 15 ppb h−1.

    Within the plume core, aerosol concentrations were strongly enhanced, with ΔCN/ΔCO ratios about one order of magnitude higher than observed in Amazon biomass burning plumes. ΔCN/ΔCO ratios tended to decrease with increasing transport time, indicative of a significant reduction in particle number by coagulation, and without substantial new particle nucleation occurring within the time/space observed. While in the background atmosphere a large fraction of the total particle number served as CCN (about 60–80% at 0.6% supersaturation, the CCN/CN ratios within the

  19. Monitoring of atmospheric particulate matter around sources of secondary inorganic aerosol

    Science.gov (United States)

    Alastuey, A.; Querol, X.; Rodríguez, S.; Plana, F.; Lopez-Soler, A.; Ruiz, C.; Mantilla, E.

    2004-09-01

    A physicochemical characterisation of airborne particulate matter (PM) was performed in a region affected by the emissions from a source of precursors of secondary inorganic aerosols (SIA, 1050 MW power plant). This characterisation sought to study the interferences of other possible natural and anthropogenic sources when monitoring PM10, PM2.5 and PM1 around this emission source. The study was performed in the semi-arid Ebro basin and Catalan and Iberian ranges (Eastern Spain) and consisted in (1) monitoring the transport and impacts on the ground of the SO2 plume (fumigation), (2) chemically characterising (25 PM components) of TSP-size fractions, and diurnal and nocturnal PM10 and PM2.5 samples, and (3) in measuring the PM mass size distribution. This PM characterisation was undertaken in ambient air, during fumigations of the SO2 plume on the ground and around other local PM sources. PM1 was found to be the best parameter for monitoring PM pollution derived from the SO2 emissions owing to the formation of ammonium-sulphate in the finest PM fractions. Three PM1 & PM2.5 events were recorded during the field measurement campaign: two events were caused by ammonium-sulphate episodes, the third was due to an African dust outbreak. PM-mass size distribution and the high correlation of PM1 with SO2 during the SO2 fumigation events suggest that a significant fraction of sulphate is formed by means of `new particle formation' processes (nucleation). PM10 presents a much higher variability (noise) than PM1 & PM2.5 owing to the re-suspension of coarse (2.5- 10 μm) mineral dust particles. The PM1 load in PM10 undergoes significant variations: 60-80% during plume fumigations, 20-60% in ambient air, and down to 10% in areas affected by mineral dust re-suspension. The daily cycles observed in some PM components (sulphate, nitrate and mineral dust elements) and the chemical features of PM are also described in detail.

  20. Aerosols and Climate

    Indian Academy of Sciences (India)

    How do Aerosols Influence Climate? Although making up only one part in a billion of the mass of the atmosphere, aerosols have the potential to significantly influ- ence the climate. The global impact of aerosol is assessed as the change imposed on planetary radiation measured in Wm-2, which alters the global temperature ...

  1. Atmospheric electricity by the radioactive aerosol after the Fukushima nuclear accident: an overview

    Science.gov (United States)

    Yamauchi, Masatoshi; Takeda, Masahiko; Makino, Masahiko; Nagamachi, Shingo

    2017-04-01

    The vertical (downward) component of the DC atmospheric electric field, or potential gradient (PG) at Kakioka, that is located 150 km southwest of the Fukushima Dai-ichi Nuclear Power Plant (FNPP1), was highly affected by the radionuclides from the FNPP1 accident. We summarize the observed effects both under clear sky and under electrified clouds. The effect by floating radionuclide (including re-suspension) continued first 40-50 days for both weather conditions, while the effect by the settled radionuclide continued a longer period. The unique features on this event that have not been detected in previous accidents/experiments are: (a) PG value recovered shortly after the initial deposition, indicating a dry deposition and blow up; (b) daily variation after the wet deposition, indicating re-suspension, and (c) short time scale for PG peaks that are relevant to cloud electricity, indicating electrostatic shielding effect by extra ions.

  2. Biological aerosol particles in the atmosphere and their impact on clouds (BIOCLOUDS)

    Science.gov (United States)

    Amato, Pierre; Attard, Eleonore; Deguillaume, Laurent; Delort, Anne-Marie; Flossmann, Andrea; Good, Nicholas; Joly, Muriel; Koop, Thomas; Möhler, Ottmar; Monier, Marie; Morris, Cindy; Oehm, Caroline; Pöschl, Ulrich; Sancelme, Martine

    2015-04-01

    The project BIOCLOUDS aimed at investigating and quantifying the role of bioaerosols in tropospheric clouds. We focused on the studies on microorganisms, mainly bacteria. To reach our objective we (1) isolated and identified INA bacterial strains in cloud waters, (2) studied in more details IN properties of bacteria isolated from cloud waters in laboratories and cloud chamber, (3) used new data as input to cloud models. 1. Isolation and Identification of INA bacterial strains in cloud waters Cloud water samples were collected at the puy de Dôme station under sterile conditions, microorganisms were cultured on agar plates and further identified by DNA sequencing coding for16SrRNA. 257 bacterial strains isolated from 25 cloud events were screened and 44 isolates were selected as they belonged to Pseudomonas, Xanthomonas and Erwinia genera which are potential INA candidates. Using the classical "Droplet Freezing method" as ice nucleation test, 7 strains were shown INA+. Their cumulative IN frequency profiles were established and showed that some of them are very efficient, for example the strain Pseudomonas syringae 13b74 started to nucleate a t-3°C and 4% of the cells were active at- 5°C. 2. Further laboratory investigations of IN properties of cloud bacterial strains All the experiments presented in this section were carried out with 3 Pseudomonas syringae strains. We tested the influence of O3, NO, UV and pH, which are atmospheric markers of anthropogenic activity, on the IN activity of the Pseudomonas strains. It was clearly shown that pH had a main influence, acidic pHs decreased the IN activity of the strains. This suggests a negative impact of human emissions on the natural capacity of bacteria to precipitate with rain. The 3 Pseudomas strains were sprayed in the AIDA cloud chamber. The survival of these strains with time before cloud formation was measured and will be used in the future to parameterize models for bacterial transport. After cloud formation

  3. Characterization of free amino acids, bacteria and fungi in size-segregated atmospheric aerosols in boreal forest: seasonal patterns, abundances and size distributions

    Science.gov (United States)

    Helin, Aku; Sietiö, Outi-Maaria; Heinonsalo, Jussi; Bäck, Jaana; Riekkola, Marja-Liisa; Parshintsev, Jevgeni

    2017-11-01

    Primary biological aerosol particles (PBAPs) are ubiquitous in the atmosphere and constitute ˜ 30 % of atmospheric aerosol particle mass in sizes > 1 µm. PBAP components, such as bacteria, fungi and pollen, may affect the climate by acting as cloud-active particles, thus having an effect on cloud and precipitation formation processes. In this study, size-segregated aerosol samples ( 10 µm) were collected in boreal forest (Hyytiälä, Finland) during a 9-month period covering all seasons and analysed for free amino acids (FAAs), DNA concentration and microorganism (bacteria, Pseudomonas and fungi). Measurements were performed using tandem mass spectrometry, spectrophotometry and qPCR, respectively. Meteorological parameters and statistical analysis were used to study their atmospheric implication for results. Distinct annual patterns of PBAP components were observed, late spring and autumn being seasons of dominant occurrence. Elevated abundances of FAAs and bacteria were observed during the local pollen season, whereas fungi were observed at the highest level during autumn. Meteorological parameters such as air and soil temperature, radiation and rainfall were observed to possess a close relationship with PBAP abundances on an annual scale.

  4. Light absorption of black carbon aerosol and its enhancement by mixing state in an urban atmosphere in South China

    Science.gov (United States)

    Lan, Zi-Juan; Huang, Xiao-Feng; Yu, Kuang-You; Sun, Tian-Le; Zeng, Li-Wu; Hu, Min

    2013-04-01

    The effects of black carbon (BC) aerosol on climate warming have been the study focus in the recent decade, and the reduction of BC is now expected to have significant near-term climate change mitigation. Large uncertainties of BC optical properties, however, still exist and seriously restrict the ability to quantify BC's climate effects. In this study, advanced instrumentation (a three-wavelength photoacoustic soot spectrometer (PASS-3) and a single particle soot photometer (SP2)) were used to measure black carbon aerosol and analyze its optical properties in a mega-city in South China, Shenzhen, during the summer of 2011. The results indicated that the average BC mass concentration was 4.0 ± 3.1 μg m-3 during the campaign, accounting for ˜11% of the total PM2.5 mass concentration. The PM2.5 light absorption at 405, 532 and 781 nm was 37.1 ± 28.1, 25.4 ± 19.0 and 17.6 ± 12.9 Mm-1, respectively. The average absorption Angstrom exponent of PM2.5 in visual spectrum (AAE405-781 nm) was 1.1 ± 0.1 during the campaign, indicating that the light absorbing carbon mainly came from vehicular emissions, with little contributions from biomass burning emissions. The mass absorption efficiency (MAE) of BC at 532 nm ranged from 5.0 to 8.5 m2 g-1 during the campaign, with an average of 6.5 ± 0.5 m2 g-1, and showed an obvious diurnal pattern with high values in the daytime. The average percentage of internally mixed BC was 24.3 ± 7.9% during the campaign, showing significant positive correlation relationship with the MAE of BC. More quantitative data analysis indicated that the internally mixed BC would amplify MAE by about 7% during the campaign, which stands in accordance with the new finding of a very recent Science magazine paper (Cappa et al., 2012) that the BC absorption enhancement due to internal mixing in the real atmosphere is relatively low, in apparent contrast to theoretical model predictions.

  5. Particulate matter and heavy metals in the atmospheric aerosol from Cartagena, Spain

    Science.gov (United States)

    Moreno-Grau, S.; Pérez-Tornell, A.; Bayo, J.; Moreno, J.; Angosto, J. M.; Moreno-Clavel, J.

    Total suspended particulate matter (TSP) and lead (Pb) concentrations were monitored at three sampling stations in Cartagena, Spain, from February 1990 to December 1998, and copper (Cu), zinc (Zn), and cadmium (Cd) atmospheric concentrations were measured from January 1991 to December 1998. TSP and Pb values were analysed from samples collected on glassfibre filters, and the concentrations of Pb, Cu, Zn, and Cd were calculated from cellulose ester filters, showing no statistically significant difference (95% C.L.) for Pb analysed in both filter types. The geographical and temporal distribution patterns were investigated. There was a trend to find the highest TSP levels during winter and autumn, and the highest Pb concentrations during the winter season. The Pb/Cd average ratios for each sampling point showed a direct anthropogenic contribution for the industrial areas, when compared with Pb/Cd ratio reported for global natural emissions. The correlation among heavy metals displayed similar results, differing from the residential area to the urban and industrial ones.

  6. Characterization of aerosol in the atmosphere at Syowa Station by X-ray fluorescence spectrometry (XRF

    Directory of Open Access Journals (Sweden)

    Tomoki Aoyama

    2010-12-01

    Full Text Available The particle size distribution has been continuously measured by optical particle counter at Syowa Station. Physical and chemical properties of particulate matter have been analyzed in the laboratory after arriving in Japan. However, the properties of particles may be changed in this case. In the present work, the atmospheric particulate matter at Syowa Station, Antarctica was characterized by X-ray fluorescence spectroscopy (XRF at Syowa Station. The advantages of this method have non destructive, rapid and simple analysis. The particle samples were collected on a Teflon filter; the obtained particles were measured by XRF (HORIBA, X-ray Analytical Microscope XGT-5000 on site soon for elemental analysis. The obtained results show that collected particles mainly contain sea salt (Na, Mg, Cl, K, Ca and soil (Si, Fe origin components. The particles from sea salt and soil origin increased under blizzard and strong wind condition. Sulfur increased in summer, and decreased in winter while particles from sea salt decreased in summer.

  7. Ship impacts on the marine atmosphere: insights into the contribution of shipping emissions to the properties of marine aerosol and clouds

    Science.gov (United States)

    Coggon, M. M.; Sorooshian, A.; Wang, Z.; Metcalf, A. R.; Frossard, A. A.; Lin, J. J.; Craven, J. S.; Nenes, A.; Jonsson, H. H.; Russell, L. M.; Flagan, R. C.; Seinfeld, J. H.

    2012-09-01

    We report properties of marine aerosol and clouds measured in the shipping lanes between Monterey Bay and San Francisco off the coast of Central California. Using a suite of aerosol instrumentation onboard the CIRPAS Twin Otter aircraft, these measurements represent a unique set of data contrasting the properties of clean and ship-impacted marine air masses in dry aerosol and cloud droplet residuals. Below-cloud aerosol exhibited average mass and number concentrations of 2 μg m-3 and 510 cm-3, respectively, which are consistent with previous studies performed off the coast of California. Enhancements in vanadium and cloud droplet number concentrations are observed concurrently with a decrease in cloud water pH, suggesting that periods of high aerosol loading are primarily linked to increased ship influence. Mass spectra from a compact time-of-flight Aerodyne aerosol mass spectrometer reveal an enhancement in the fraction of organic at m/z 42 (f42) and 99 (f99) in ship-impacted clouds. These ions are well correlated to each other (R2>0.64) both in and out of cloud and constitute 14% (f44) and 3% (f99) of organic mass during periods of enhanced sulfate. High-resolution mass spectral analysis of these masses from ship measurements suggests that the ions responsible for this variation were oxidized, possibly due to cloud processing. We propose that the organic fractions of these ions be used as a metric for determining the extent to which cloud-processed ship emissions impact the marine atmosphere where (f42 > 0.15; f99 > 0.04) would imply heavy influence from shipping emissions, (0.05 < f42 < 0.15; 0.01 < f99 < 0.04) would imply moderate, but persistent, influences from ships, and (f42 < 0.05; f99 < 0.01) would imply clean, non-ship-influenced air.

  8. Determination of Cr(III, Cr(VI and total chromium in atmospheric aerosol samples

    Directory of Open Access Journals (Sweden)

    Catrambone M.

    2013-04-01

    Full Text Available This study addresses the optimization and validation of an analytical method based on the ultrasound-assisted extraction of soluble Cr from atmospheric particulate matter (PM and subsequent determination of Cr(III and Cr(VI by catalytic adsorptive stripping voltammetry (CAdSV by using diethylenetriammino pentaacetic acid (DTPA as complexing agent in the presence of nitrate. We evaluated the influence of various filter materials and of extracting conditions and validated the method on both reference material and real PM10 samples. The accuracy of total extractable Cr determination was checked by parallel ICP-OES measurements. The determination of total chromium was performed by ED-XRF. Results of field campaigns carried out in two industrial areas (North Italy and Tunis and at a peri-urban site near Rome are reported. At the peri-urban site, the total Cr concentration in PM10 ranged from 2 to 5 ng/m3, with a soluble fraction of 5-13%, and Cr(VI concentration was always below the detection limits (50 pg/m3. In the industrial area of Northern Italy, total Cr concentration ranged between 6 and 11 ng/m3, the soluble fraction was about 11-28% and detectable amounts of Cr(VI were found, with a Cr(VI/Cr(III ratio ranging from 0.5 to 2.5. A further increase of Cr(VI concentration was evidenced at the industrial site of Tunis, where the total Cr concentration ranged from 6 to 26 ng/m3, with a soluble fraction accounting for about 8-44% and a Cr(VI/Cr(III ranging from 1.6 to 3.6. The results of size-segregated samples, collected in Northen Italy by a 10-stage cascade impactor, indicate a relevant fine fraction of Cr(VI, with Cr(VI/Cr(III ratios increasing with the decrease of particle size.

  9. Influence of atmospheric parameters on vertical profiles and horizontal transport of aerosols generated in the surf zone

    NARCIS (Netherlands)

    Kusmierczyk-Michulec, J.; Tedeschi, G.; Eijk, A.M.J. van; Piazzolac, J.

    2013-01-01

    The vertical and horizontal transport of aerosols generated over the surf zone is discussed. Experimental data were collected during the second campaign of the Surf Zone Aerosol Experiment that took place in Duck NC (USA) in November 2007. The Empirical Orthogonal Function (EOF) method was used to

  10. Tropospheric Aerosols

    Science.gov (United States)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    It is widely believed that "On a clear day you can see forever," as proclaimed in the 1965 Broadway musical of the same name. While an admittedly beautiful thought, we all know that this concept is only figurative. Aside from Earth's curvature and Rayleigh scattering by air molecules, aerosols - colloidal suspensions of solid or liquid particles in a gas - limit our vision. Even on the clearest day, there are billions of aerosol particles per cubic meter of air.Atmospheric aerosols are commonly referred to as smoke, dust, haze, and smog, terms that are loosely reflective of their origin and composition. Aerosol particles have arisen naturally for eons from sea spray, volcanic emissions, wind entrainment of mineral dust, wildfires, and gas-to-particle conversion of hydrocarbons from plants and dimethylsulfide from the oceans. However, over the industrial period, the natural background aerosol has been greatly augmented by anthropogenic contributions, i.e., those produced by human activities. One manifestation of this impact is reduced visibility (Figure 1). Thus, perhaps more than in other realms of geochemistry, when considering the composition of the troposphere one must consider the effects of these activities. The atmosphere has become a reservoir for vast quantities of anthropogenic emissions that exert important perturbations on it and on the planetary ecosystem in general. Consequently, much recent research focuses on the effects of human activities on the atmosphere and, through them, on the environment and Earth's climate. For these reasons consideration of the geochemistry of the atmosphere, and of atmospheric aerosols in particular, must include the effects of human activities. (201K)Figure 1. Impairment of visibility by aerosols. Photographs at Yosemite National Park, California, USA. (a) Low aerosol concentration (particulate matter of aerodynamic diameter less than 2.5 μm, PM2.5=0.3 μg m-3; particulate matter of aerodynamic diameter less than 10

  11. Influence of the micro-physical properties of the aerosol on the atmospheric correction of OLI data acquired over desert area

    Science.gov (United States)

    Manzo, Ciro; Bassani, Cristiana

    2016-04-01

    This paper focuses on the evaluation of surface reflectance obtained by different atmospheric correction algorithms of the Landsat 8 OLI data considering or not the micro-physical properties of the aerosol when images are acquired in desert area located in South-West of Nile delta. The atmospheric correction of remote sensing data was shown to be sensitive to the aerosol micro-physical properties, as reported in Bassani et al., 2012. In particular, the role of the aerosol micro-physical properties on the accuracy of the atmospheric correction of remote sensing data was investigated [Bassani et al., 2015; Tirelli et al., 2015]. In this work, the OLI surface reflectance was retrieved by the developed OLI@CRI (OLI ATmospherically Corrected Reflectance Imagery) physically-based atmospheric correction which considers the aerosol micro-physical properties available from the two AERONET stations [Holben et al., 1998] close to the study area (El_Farafra and Cairo_EMA_2). The OLI@CRI algorithm is based on 6SV radiative transfer model, last generation of the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) radiative transfer code [Kotchenova et al., 2007; Vermote et al., 1997], specifically developed for Landsat 8 OLI data. The OLI reflectance obtained by the OLI@CRI was compared with reflectance obtained by other atmospheric correction algorithms which do not consider micro-physical properties of aerosol (DOS) or take on aerosol standard models (FLAASH, implemented in ENVI software). The accuracy of the surface reflectance retrieved by different algorithms were calculated by comparing the spatially resampled OLI images with the MODIS surface reflectance products. Finally, specific image processing was applied to the OLI reflectance images in order to compare remote sensing products obtained for same scene. The results highlight the influence of the physical characterization of aerosol on the OLI data improving the retrieved atmospherically corrected

  12. Stable hydrogen isotope composition of n-alkanes in urban atmospheric aerosols in Taiyuan, China

    Science.gov (United States)

    Bai, Huiling; Li, Yinghui; Peng, Lin; Liu, Xiangkai; Liu, Xiaofeng; Song, Chongfang; Mu, Ling

    2017-03-01

    The hydrogen isotope compositions (δD) of n-alkanes associated with particulate matter with a diameter of ≤10 μm from Taiyuan, China, during heating and non-heating periods were measured via gas chromatography-isotope ratio mass spectrometry to reveal the spatial and temporal characteristics of five functional zones and to provide another constraint on atmospheric pollutants. The δD values of n-C16 to n-C31 during the heating and non-heating periods ranged from -235.9‰ to -119.8‰ and from -231.3‰ to -129.2‰, respectively, but these similar spans had different distribution features. During the heating period, the δD distributions between non-central heating and commercial districts were consistent, as were those between residential and industrial districts; the n-alkanes came from two or more types of emission sources. Coal soot might be the primary local emission source, but not the only source. During the non-heating period, the n-alkanes of n-C16 to n-C20 were more depleted in D with the increasing carbon number in all functional zones, but there was no rule for n-C21 to n-C31. Specifically, coal soot and vehicle exhaust might be the primary sources of n-alkanes for non-central heating districts in the heating and non-heating periods, respectively, according to the δD distribution of n-C18 to n-C22; gasoline vehicle exhaust might be an n-alkane source, and the hydrogen isotope fractionation effect during the condensation process should be a pollution mechanism for the commercial district during the heating period; the δD distribution difference of n-C16 to n-C18 between the two periods in the residential and industrial districts was consistent, which indicates a similar source of fossil fuel combustion and a similar isotope fractionation effect during the non-heating period.

  13. Impact of atmospheric boundary layer depth variability and wind reversal on the diurnal variability of aerosol concentration at a valley site

    Energy Technology Data Exchange (ETDEWEB)

    Pal, S., E-mail: sp5hd@Virginia.EDU; Lee, T.R.; Phelps, S.; De Wekker, S.F.J.

    2014-10-15

    The development of the atmospheric boundary layer (ABL) plays a key role in affecting the variability of atmospheric constituents such as aerosols, greenhouse gases, water vapor, and ozone. In general, the concentration of any tracers within the ABL varies due to the changes in the mixing volume (i.e. ABL depth). In this study, we investigate the impact on the near-surface aerosol concentration in a valley site of 1) the boundary layer dilution due to vertical mixing and 2) changes in the wind patterns. We use a data set obtained during a 10-day field campaign in which a number of remote sensing and in-situ instruments were deployed, including a ground-based aerosol lidar system for monitoring of the ABL top height (z{sub i}), a particle counter to determine the number concentration of aerosol particles at eight different size ranges, and tower-based standard meteorological instruments. Results show a clearly visible decreasing trend of the mean daytime z{sub i} from 2900 m AGL (above ground level) to 2200 m AGL during a three-day period which resulted in increased near-surface pollutant concentrations. An inverse relationship exists between the z{sub i} and the fine fraction (0.3–0.7 μm) accumulation mode particles (AMP) on some days due to the dilution effect in a well-mixed ABL. These days are characterized by the absence of daytime upvalley winds and the presence of northwesterly synoptic-driven winds. In contrast, on the days with an onset of an upvalley wind circulation after the morning transition, the wind-driven local transport mechanism outweighs the ABL-dilution effect in determining the variability of AMP concentration. The interplay between the ABL depth evolution and the onset of the upvalley wind during the morning transition period significantly governs the air quality in a valley and could be an important component in the studies of mountain meteorology and air quality. - Highlights: • Role of atmospheric boundary layer depth on particle

  14. Infrared studies of temperature-dependent phase transitions in ammonium sulfate aerosol and the development of a visible light scattering technique to measure atmospheric particle compositions

    Science.gov (United States)

    Onasch, Timothy Bruce

    1999-10-01

    Sulfate containing particles exist globally throughout the atmosphere and impact its chemistry and radiative properties. Under the low temperature conditions found in the upper troposphere and lower stratosphere, sulfate particles act as nuclei for cirrus clouds and facilitate heterogeneous reactions which affect ozone chemistry. Both of these processes are dependent upon the chemical composition and phase of the background aerosol, and thus the behavior of these particles at low temperatures. This thesis represents two approaches undertaken to investigate the composition and phase of atmospheric aerosols. First, a flow tube system has been developed to study the low temperature behavior of atmospherically relevant particles within a controlled laboratory environment. Second, a visible light scattering technique has been developed to characterize the physical properties of particles in situ from an aircraft platform. The relative humidities of temperature-dependent phase transitions in ammonium sulfate aerosols were measured within a flow tube system. A chilled-mirror hygrometer measured the relative humidity and Fourier transform infrared spectroscopy was utilized to probe the phase of the particles and to characterize their microphysical properties. The relative humidity of deliquescence changed from 80% to 82% over the temperature range from 294.8 K to 258.0 K, in agreement with thermodynamic theory. The efflorescence relative humidity of submicron ammonium sulfate particles increased slightly from 32% to 39% as the temperature decreased from 294.8 K to 234.3 K. The latter result suggests that salt particles may exist as metastable solution droplets under low relative humidity conditions for significant time periods in the upper troposphere. To measure particle refractive indices in situ, a visible light scattering technique based on NCAR's Multiangle Aerosol Spectrometer Probe (MASP) was developed. The MASP was calibrated with monodisperse particles having

  15. Interactions of Gas-Phase Nitric/Nitrous Acids and Primary Organic Aerosol in the Atmosphere of Houston, TX

    Science.gov (United States)

    Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Whitlow, S. I.; Lefer, B. L.; Flynn, J.; Rappenglück, B.

    2007-12-01

    Concentrations of aerosol and gas-phase pollutants were measured on the roof of an 18-story building during the Texas Air Quality Study II Radical and Aerosol Measurement Project (TRAMP) from August 15 through September 28, 2006. Aerosol measurements included size-resolved, non-refractory mass concentrations of ammonium, nitrate, sulfate, chloride, and organic aerosol in submicron particles using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS). Particulate water-soluble organic carbon (PWSOC) was quantified using a mist chamber/total organic carbon analysis system. Concentration data for gas-phase pollutants included those for nitric acid (HNO3), nitrous acid (HONO), and hydrochloric acid (HCl) collected using a mist chamber/ion chromatographic technique, oxides of nitrogen (NOx) collected using a chemiluminescent method, and carbon monoxide (CO) collected using an infrared gas correlation wheel instrument. Coincident increases in nitrate and organic aerosol mass concentrations were observed on many occasions throughout the measurement campaign, most frequently during the morning rush hour. Based on the lack of organic aerosol processing (defined by the ratio of m/z = 44/57 in the Q-AMS spectra), strong correlation with NOx and CO, and a lack of significant increase in PWSOC concentration, the spikes in organic aerosol were likely associated with primary organic aerosol (POA). During these events, gas-phase HNO3 concentration decreases were observed simultaneously with increases in gas-phase HONO concentrations. These data likely indicate uptake of HNO3 and subsequent heterogeneous conversion to HONO involving POA. Preliminary calculations show that HNO3 partitioning could account for the majority of the observed HONO and aerosol nitrate concentrations during these events. Q-AMS chloride and HCl data also indicate uptake of chloride by particles during these events. This phenomenon was also observed during the night, but these nocturnal events were less

  16. Nonlinear relationships between atmospheric aerosol and its gaseous precursors: Analysis of long-term air quality monitoring data by means of neural networks

    Directory of Open Access Journals (Sweden)

    I. B. Konovalov

    2003-01-01

    Full Text Available The nonlinear features of the relationships between concentrations of aerosol and volatile organic compounds (VOC and nitrogen oxides (NOx in urban environments are revealed directly from data of long-term routine measurements of NOx, VOC, and total suspended particulate matter (PM. The main idea of the method is development of special empirical models based on artificial neural networks. These models, that are basically, the nonlinear extension of the commonly used linear statistical models provide the best fit for the real (nonlinear PM-NOx-VOC relationships under different atmospheric conditions. Such models may be useful in the context of various scientific and practical problems related to atmospheric aerosols. The method is demonstrated on an example of two empirical models based on independent data-sets collected at two air quality monitoring stations at South Coast Air Basin, California. It is shown that in spite of a rather large distance between the monitoring stations (more than 50 km and thus substantially different environmental conditions, the empirical models demonstrate several common qualitative features. Specifically, under definite conditions, a decrease in the level of NOx or VOC may lead to an increase in mass concentration of aerosol. It is argued that these features are due to the nonlinear dependence of hydroxyl radical on VOC and NOx.

  17. Solid-phase extraction of organic compounds in atmospheric aerosol particles collected with the particle-into-liquid sampler and analysis by liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Parshintsev, Jevgeni; Hyötyläinen, Tuulia; Hartonen, Kari; Kulmala, Markku; Riekkola, Marja-Liisa

    2010-01-15

    Atmospheric aerosol particles, collected with the particle-into-liquid sampler at SMEARII station in Finland in mid-August 2007, were analysed for biogenic acids. The sample pretreatment method, comprising solid-phase extraction with anion exchange and hydrophilic-lipophilic balance materials, was optimized. Extraction efficiencies of solid-phase extraction from 10 and 20ml samples were about 100%, with average relative standard deviation of 8.9%, in concentration range from 12.5 to 50ng/ml of the acid. Extraction of aldehydes was less successful, with efficiencies from 69 to 163% and average 10% deviation. Pretreated samples were analysed by reversed phase high performance liquid chromatography with ion trap mass spectrometric detection. Limits of detection achieved for organic acids with the analytical procedure developed ranged from 9 to 27microg/l of extracted sample, while limits of quantitation were from 31 to 90microg/l. Oxidation with ozone was used for the preparation of the acid of beta-caryophyllene (beta-caryophyllinic acid), which was also studied in aerosol samples. MS(2) experiments were used to confirm the identification of trans-pinic, trans-pinonic and beta-caryophyllinic acids. Azelaic, hexadecanoic, cis-pinonic, and cis- and trans-pinic acids were quantitated in the samples with use of authentic standards, while the concentrations of trans-pinonic and beta-caryophyllinic acids were determined with cis-pinonic acid as surrogate. Also, the contribution of beta-caryophyllene oxidation products to aerosol organic carbon was evaluated. Aldehydes could not be analysed in real samples due to the insufficient extraction. The particle-into-liquid sampler proved to be suitable for the collection of aerosol particles for the elucidation of daily and diurnal variation of selected species. The optimized sample pretreatment, together with the analysis method, offer a promising approach for the study of aerosol chemical composition, where artifact formation is

  18. Sources of atmospheric aerosol from long-term measurements (5 years) of chemical composition in Athens, Greece.

    Science.gov (United States)

    Paraskevopoulou, D; Liakakou, E; Gerasopoulos, E; Mihalopoulos, N

    2015-09-15

    To identify the sources of aerosols in Greater Athens Area (GAA), a total of 1510 daily samples of fine (PM 2.5) and coarse (PM 10-2,5) aerosols were collected at a suburban site (Penteli), during a five year period (May 2008-April 2013) corresponding to the period before and during the financial crisis. In addition, aerosol sampling was also conducted in parallel at an urban site (Thissio), during specific, short-term campaigns during all seasons. In all these samples mass and chemical composition measurements were performed, the latest only at the fine fraction. Particulate organic matter (POM) and ionic masses (IM) are the main contributors of aerosol mass, equally contributing by accounting for about 24% of the fine aerosol mass. In the IM, nss-SO4(-2) is the prevailing specie followed by NO3(-) and NH4(+) and shows a decreasing trend during the 2008-2013 period similar to that observed for PM masses. The contribution of water in fine aerosol is equally significant (21 ± 2%), while during dust transport, the contribution of dust increases from 7 ± 2% to 31 ± 9%. Source apportionment (PCA and PMF) and mass closure exercises identified the presence of six sources of fine aerosols: secondary photochemistry, primary combustion, soil, biomass burning, sea salt and traffic. Finally, from winter 2012 to winter 2013 the contribution of POM to the urban aerosol mass is increased by almost 30%, reflecting the impact of wood combustion (dominant fuel for domestic heating) to air quality in Athens, which massively started in winter 2013. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Using a moving measurement platform for determining the chemical composition of atmospheric aerosols between Moscow and Vladivostok

    Directory of Open Access Journals (Sweden)

    S. Kuokka

    2007-09-01

    Full Text Available The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements of aerosol physical and chemical properties were made from an observatory carriage connected to a passenger train. Black carbon (BC concentrations in fine particles (PM2.5, aerodynamic diameter <2.5 μm were measured with an aethalometer using a five-minute time resolution. Concentrations of inorganic ions and some organic compounds (Cl, NO3, SO42−, Na+, NH4+, K+, Ca2+, Mg2+, oxalate and methane sulphonate were measured continuously by using an on-line system with a 15-min time resolution. In addition, particle volume size distributions were determined for particles in the diameter range 3–850 nm using a 10-min time resolution. The continuous measurements were completed with 24-h PM2.5 filter samples stored in a refrigerator and analyzed later in a chemical laboratory. The analyses included the mass concentrations of PM2.5, ions, monosaccharide anhydrides (levoglucosan, galactosan and mannosan and trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V and Zn. The mass concentrations of PM2.5 varied in the range of 4.3–34.8 μg m−3 with an average of 21.6 μg m−3. Fine particle mass consisted mainly of BC (average 27.6%, SO42− (13.0%, NH4+ (4.1% and NO3 (1.4%. One of the major constituents was obviously organic carbon which was not determined. The contribution of BC was high compared with other studies made in Europe and Asia. High concentrations of ions, BC and particle volume were observed between Moscow and roughly 4000 km east of it, as well as close to Vladivostok

  20. Estimation of atmospheric aerosol composition from ground-based remote sensing measurements of Sun-sky radiometer

    Science.gov (United States)

    Xie, Y. S.; Li, Z. Q.; Zhang, Y. X.; Zhang, Y.; Li, D. H.; Li, K. T.; Xu, H.; Zhang, Y.; Wang, Y. Q.; Chen, X. F.; Schauer, J. J.; Bergin, M.

    2017-01-01

    Remote sensing provides aerosol loading information, but to address climate and air quality model validation, there are additional needs to acquire aerosol composition information. In this study, a comprehensive aerosol composition model is established to quantify black carbon (BC), brown carbon (BrC), mineral dust (DU), particulate organic matters, ammonium sulfate like (AS), sea salt, and aerosol water uptake. We develop forward modeling of aerosol components, including microphysical parameters (real and imaginary refractive indices, volume fraction ratio of fine to coarse mode, and sphericity) and hygroscopic growth models, and propose an optimization scheme to estimate the components. The uncertainties caused by input parameters are also assessed. Sun-sky radiometer measurements and meteorological data obtained during a campaign in Huairou, Beijing, are processed to estimate aerosol components, which are further compared with synchronous in situ chemical measurements. The results show generally good consistencies between remotely estimated and measured components (e.g., correlation coefficients for BC, BrC, AS, and PM2.5 lie in about 0.8-0.9). The comparisons between modeled and observed microphysical parameters also show good agreements, with the exception of sphericity, which is likely caused by high uncertainties of this parameter. Sensitivity studies show that BC and BrC are highly sensitive to imaginary refractive index, while DU is strongly correlated to both volume size and sphericity. The performance of composition retrieval is expected to be improved when the sphericity uncertainty is significantly reduced.

  1. Retrieval of aerosol mass load (PM10) from MERIS/Envisat top of atmosphere spectral reflectance measurements

    Science.gov (United States)

    Rohen, G. J.; von Hoyningen-Huene, W.; Kokhanovsky, A.; Dinter, T.; Vountas, M.; Burrows, J. P.

    2010-12-01

    A retrieval of particulate matter concentration (PM10) from satellite data is presented as well as improvements of the aerosol optical depth retrieval by the Bremen aerosol algorithm. The add-on retrieval of particulate matter uses the derivation of the effective radii from the Ångstroem exponents and an assumed log-normal size distribution function. The Ångstroem exponent is derived through the multi-channel approach using MERIS/Envisat data, and benefits from the fitting of a smooth spectral slope of aerosol optical depth and the surface reflectance. The advantage of the retrieval is that this retrieval of the aerosol mass, i.e., in particular the effective radius, is exclusively based on spectral information from satellite measurements, global aerosol models, and meteorological parameters. ECMWF Boundary layer height, humidity, temperature, and pressure data are used in the retrieval; a retrieval of PM inferred without meteorological information and a proper BRDF is shown to be not very promising. Over the city of Hamburg, the aerosol optical depths agree within a standard deviation of 0.03 and 0.068 for all thirteen wavelengths between 412 and 885 nm, compared with AERONET and ground based air quality measurements; the particulate matter concentrations show agreement with a correlation factor of 0.64. In addition to the urban site of Hamburg, comparisons of PM10 measurements over rural sites in Germany exhibit a correlation coefficient of 0.75.

  2. Atmospheric aerosol variability above the Paris Area during the 2015 heat wave - Comparison with the 2003 and 2006 heat waves

    Science.gov (United States)

    Chazette, Patrick; Totems, Julien; Shang, Xiaoxia

    2017-12-01

    The aerosol layers during the heat wave of July 2015 over Paris Area have been studied using a N2-Raman lidar with co- and cross-polarized channels. The lidar observations are examined to allow the identification of main aerosol types and their origins, in synergy with measurements of the AERONET sunphotometer network and back trajectory studies from the HYSPLIT model. The results are compatible with spaceborne observations of MODIS and CALIOP. As for previous heat waves of August 2003 and July 2006 occurring in France, the aerosol optical thickness is very large, up to 0.8 at the lidar wavelength of 355 nm (between 0.5 and 0.7 at 550 nm). However, air mass trajectories highlight that the observed aerosol layers may have multiple and diverse origins during the 2015 heat wave (North America, Northwest Africa, Southern and Northern Europe). Biomass burning, pollution and desert dust aerosols have been identified, using linear particle depolarization ratio, lidar ratio and analysis of back trajectories initiated at the altitudes and arrival times of the plumes. These layers are elevated and are shown to have little impact on surface aerosol concentrations (PM10 albedo distributions at 550 nm: 0.90 ± 0.03, 0.95 ± 0.02 and 0.93 ± 0.04 for 2003, 2006 and 2015, respectively.

  3. The potential importance of non-local, deep transport on the energetics, momentum, chemistry, and aerosol distributions in the atmospheres of Earth, Mars, and Titan

    Science.gov (United States)

    Rafkin, Scot C. R.

    2012-01-01

    A review of non-local, deep transport mechanisms in the atmosphere of Earth provides a good foundation for examining whether similar mechanisms are operating in the atmospheres of Mars and Titan. On Earth, deep convective clouds in the tropics constitute the upward branch of the Hadley Cell and provide a conduit through which energy, moisture, momentum, aerosols, and chemical species are moved from the boundary layer to the upper troposphere and lower stratosphere. This transport produces mid-tropospheric minima in quantities such as water vapor and moist static energy and maxima where the clouds detrain. Analogs to this terrestrial transport are found in the strong and deep thermal circulations associated with topography on Mars and with Mars dust storms. Observations of elevated dust layers on Mars further support the notion that non-local deep transport is an important mechanism in the atmosphere of Mars. On Titan, the presence of deep convective clouds almost assures that non-local, deep transport is occurring and these clouds may play a role in global cycling of energy, momentum, and methane. Based on the potential importance of non-local deep transport in Earth's atmosphere and supported by evidence for such transport in the atmospheres of Mars and Titan, greater attention to this mechanism in extraterrestrial atmospheres is warranted.

  4. Variability of Atmospheric Radon-222 and Secondary Aerosol Components in Accordance with Air Mass Transport Pathways at Jeju Island, Korea, during 2011-2014

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Jun-Oh; Song, Jung-Min; Kim, Won-Hyung; Kang, Chang-Hee [Jeju National University, Jeju (Korea, Republic of); Chambers, Scott D.; Williams, Alastair G. [Australian Nuclear Science and Technology Organisation, Kirrawee DC (Australia); Lee, Chulkyu [Korea Meteorological Administration, Seoul (Korea, Republic of)

    2016-06-15

    Real-time monitoring of hourly atmospheric Radon-222 concentration and three daily monitoring of the secondary aerosol components of PM{sub 10} were performed throughout 2011-2014 at Gosan station, Jeju Island, in order to characterize their background levels and temporal variation. The annual mean radon and PM{sub 10} mass concentrations were 2326 ± 1198 mBq/m{sup 3} and 37.1 ± 19.5 μg/m{sup 3}, respectively. Based on cluster analyses of air mass back trajectories, the frequencies of air masses originating from continental China, the Korean Peninsula, and North Pacific Ocean routes were 53, 28, and 19%, respectively. When the air masses were transported to Jeju Island from continental China, the concentrations of radon and secondary aerosol components (nss-SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, NH{sub 4}{sup +}) were relatively high: 2577 mBq/m{sup 3} and 14.4 μg/m{sup 3}, respectively. In cases when the air masses have moved from the Korean Peninsula, the corresponding concentrations were 2247 mBq/m{sup 3} and 11.4 μg/m{sup 3}, respectively. On the other hand, when the air masses came from the North Pacific Ocean, their radon and secondary aerosol concentrations decreased much further, 1372 mBq/m{sup 3} and 10.5 μg/m{sup 3}, respectively. Consequently, the variability of atmospheric radon concentrations at Gosan station might be characterized by synoptic changes in air mass fetch as well as diurnal changes in atmospheric mixing depth.

  5. Scattering by Atmospheric Particles: From Aerosols to Clouds with the Point-Spread Function ... using Water, Milk, Plastic Cups, and a Laser Pointer

    Science.gov (United States)

    Davis, A. B.

    2015-12-01

    Planetary atmospheres are made primarily of molecules, and their optical properties are well known. They scatter sunlight across the spectrum, but far more potently at shorter wavelengths. Consequently, they redden the Sun as it sets and, at the same time, endow the daytime sky with its characteristic blue hue. There are also microscopic atmospheric particulates that are equally omnipresent because small enough (up to ~10s of microns) to remain lofted for long periods of time. However, in contrast with molecules of the major gases, their concentrations are highly variable in space and time. Their optical properties are also far more interesting. These airborne particles are either solid---hence the word "aerosols"---or liquid, most notably in the form of cloud droplets. Needless to say that both aerosols and clouds have major impacts on the balance of the Earth's climate system. Harder to understand, but nonetheless true, is that their climate impacts are much harder to assess by Earth system modelers than those of greenhouse gases such as CO2. That makes them prime targets of study by multiple approaches, including ground- and space-based remote sensing. To characterize aerosols and clouds quantitatively by optical remote sensing methods, either passive (sunlight-based) or active (laser-based), we need predictive capability for the signals recorded by sensors, whether ground-based, airborne, or carried by satellites. This in turn draws on the physical theory of "radiative transfer" that describes how the light propagates and scatters in the molecular-and-particulate atmosphere. This is a challenge for remote sensing scientists. I will show why by simulating with simple means the point spread function or "PSF" of scattering particulate atmospheres with varying opacity, thus covering tabletop analogs of the pristine air, the background aerosol, all the way to optically thick cloudy airmasses. I will also show PSF measurements of real clouds over New Mexico and

  6. Analysis of Atmospheric Aerosols Collected in an Urban Area in Upstate NY Using Proton Induced X-ray Emission (PIXE) Spectroscopy

    Science.gov (United States)

    Smith, Jeremy; Ali, Salina; Nadareski, Benjamin; Safiq, Alexandrea; Yoskowitz, Joshua; Labrake, Scott; Vineyard, Michael

    2013-10-01

    We examined atmospheric aerosol samples collected in Schenectady NY for evidence of pollution. We collected aerosol samples using a nine stage cascade impactor which distributes the particulate matter by aerodynamic size onto 7.5 μm Kapton foils. We then used a 1MV electrostatic Pelletron accelerator to produce a 2.2 MeV proton beam to hit the impacted foils. X-ray intensity versus energy spectra were collected using an Amptek x-ray detector where the x-rays are produced from the proton beam interacting with the sample. This is called PIXE. The elemental composition and concentrations of the elements present in the aerosol samples were determined using a software package called GUPIX. We have found elements ranging from Al to Pb and in particular have found significant amounts of Pb and Br on some of our impacted foils, with a Br/Pb ratio of 0.6 +/- 0.2 which agrees with previous studies. This result suggests the presence of leaded aviation fuel perhaps due to the proximity of the collection site to a small airport with a significant amount of general aviation traffic. Union College.

  7. Contribution of fungi to primary biogenic aerosols in the atmosphere: active discharge of spores, carbohydrates, and inorganic ions by Asco- and Basidiomycota

    Science.gov (United States)

    Elbert, W.; Taylor, P. E.; Andreae, M. O.; Pöschl, U.

    2006-11-01

    Spores and related chemical compounds from actively spore-discharging Ascomycota (AAM) and actively spore-discharging Basidiomycota (ABM) are primary biogenic components of air particulate matter (characteristic size range 1-10 μm). Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001) indicate that the forcible discharge of fungal spores may account for a large proportion of coarse air particulate matter in tropical rainforest regions during the wet season. For the particle diameter range of 1-10 μm, the estimated proportions are ~25% during day-time, ~45% at night, and ~35% on average. For the sugar alcohol, mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively discharged basidiospores (ABS), and that the literature-derived emission ratio of about 5 pg per ABS may be taken as a representative average. ABM emissions may account for most of the atmospheric abundance of mannitol, and can explain the observed diurnal cycle (higher abundance at night). ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter, but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night). AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season, and they can also explain the observed diurnal cycle (higher abundance at night). The results of our investigations and budget calculations for tropical rainforest aerosols are consistent with measurements performed at other locations. Based on the average abundance of mannitol in particulate matter, which is consistent with the above emission ratio and the observed abundance of ABS, we have also calculated a value of ~17 Tg yr-1 as a first estimate for the global average emission rate of ABS over land surfaces

  8. Two year-long continuous monitoring of PM1 aerosol chemical composition at the Cyprus Atmospheric Observatory. Source apportionment of the Organic content and geographic origins.

    Science.gov (United States)

    Stavroulas, Iasonas; Pikridas, Michael; Oikonomou, Kostantina; Vasiliadou, Emily; Savvides, Chrysanthos; Vrekoussis, Mihalis; Mihalopoulos, Nikolaos; Gros, Valerie; Sciare, Jean

    2017-04-01

    Particulate matter with diameter smaller than 1{μ}m (PM1) induces direct and indirect effects on local and regional pollution, global climate and health. As of the beginning of 2015, the chemical composition of submicron aerosols, is continuously being monitored at the newly established Cyprus Atmospheric Observatory (CAO, http://www.cyi.ac.cy/index.php/cao.html), a national facility of the ACTRIS Research Infrastructure operated by The Cyprus Institute. Cyprus, an island located in the Eastern Mediterranean Middle East region and influenced by diverse air masses throughout the year, is ideal for monitoring photochemically aged aerosols and gaseous pollutants of both natural and anthropogenic origin. Furthermore this is a unique dataset for this area in such proximity to the Middle East, a poorly documented area in terms of atmospheric aerosol observations. An Aerodyne Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) is currently deployed at the CAO premises (35.04N - 33.06E) situated at the rural area of Agia Marina Xyliatou on the foothill of mount Troodos at an elevation of 532m above sea level (asl). The ACSM delivers chemical composition of the major non-refractory aerosol (PM1) chemical constituents (organics, sulfate, nitrate, ammonium, chloride) with an effective (close to 100{%}) collection efficiency for particles in the diameter range of 65-700 nm at a 30 minute temporal resolution. Black Carbon (BC) was also monitored using both Magee Scientific AE-31 and AE-33 aethalometers. Quality control of the PM chemical dataset was conducted by comparison with chemical analysis performed on collocated 24-h filter samples (PM1) and comparison with 1-h PM2.5 derived from a Thermo Scientific TEOM (1400a) Monitor. Positive Matrix Factorization (PMF) was conducted and different organic aerosol factors were distinguished using the Igor based SoFi toolkit utilizing the ME-2 multilinear engine. Air mass origin was investigated for each measurement day using the

  9. Hygroscopic properties of atmospheric aerosol particles over the Eastern Mediterranean: implications for regional direct radiative forcing under clean and polluted